Observation of vapor pressure enhancement of rare-earth metal-halide salts in the temperature range relevant to metal-halide lamps

Energy Technology Data Exchange (ETDEWEB)

Curry, J. J.; Henins, A.; Hardis, J. E. [National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Estupinan, E. G. [Osram Sylvania Inc., Beverly, Massachusetts 01915 (United States); Lapatovich, W. P. [Independent Consultant, 51 Pye Brook Lane, Boxford, Massachusetts 01921 (United States); Shastri, S. D. [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

2012-02-20

Total vapor-phase densities of Dy in equilibrium with a DyI{sub 3}/InI condensate and Tm in equilibrium with a TmI{sub 3}/TlI condensate have been measured for temperatures between 900 K and 1400 K. The measurements show strong enhancements in rare-earth vapor densities compared to vapors in equilibrium with the pure rare-earth metal-halides. The measurements were made with x-ray induced fluorescence on the sector 1-ID beam line at the Advanced Photon Source. The temperature range and salt mixtures are relevant to the operation of metal-halide high-intensity discharge lamps.

Metal vapor vacuum arc ion sources

International Nuclear Information System (INIS)

Brown, I.G.; Dickinson, M.R.; Galvin, J.E.; Godechot, X.; MacGill, R.A.

1990-06-01

We have developed a family of metal vapor vacuum are (MEVVA) high current metal ion sources. The sources were initially developed for the production of high current beams of metal ions for heavy ion synchrotron injection for basic nuclear physics research; more recently they have also been used for metal ion implantation. A number of different embodiments of the source have been developed for these specific applications. Presently the sources operate in a pulsed mode, with pulse width of order 1 ms and repetition rate up to 100 pps. Beam extraction voltage is up to 100 kV, and since the ions produced in the vacuum arc plasma are in general multiply ionized the ion energy is up to several hundred keV. Beam current is up to several Amperes peak and around 10 mA time averaged delivered onto target. Nearly all of the solid metals of the Periodic Table have been use to produce beam. A number of novel features have been incorporated into the sources, including multiple cathodes and the ability to switch between up to 18 separate cathode materials simply and quickly, and a broad beam source version as well as miniature versions. here we review the source designs and their performance. 45 refs., 7 figs

Considerations of particle vaporization and analyte diffusion in single-particle inductively coupled plasma-mass spectrometry

International Nuclear Information System (INIS)

Ho, Koon-Sing; Lui, Kwok-On; Lee, Kin-Ho; Chan, Wing-Tat

2013-01-01

The intensity of individual gold nanoparticles with nominal diameters of 80, 100, 150, and 200 nm was measured using single-particle inductively coupled plasma-mass spectrometry (ICP-MS). Since the particles are not perfectly monodisperse, a distribution of ICP-MS intensity was obtained for each nominal diameter. The distribution of particle mass was determined from the transmission electron microscopy (TEM) image of the particles. The distribution of ICP-MS intensity and the distribution of particle mass for each nominal diameter were correlated to give a calibration curve. The calibration curves are linear, but the slope decreases as the nominal diameter increases. The reduced slope is probably due to a smaller degree of vaporization of the large particles. In addition to the degree of particle vaporization, the rate of analyte diffusion in the ICP is an important factor that determines the measured ICP-MS intensity. Simulated ICP-MS intensity versus particle size was calculated using a simple computer program that accounts for the vaporization rate of the gold nanoparticles and the diffusion rate and degree of ionization of the gold atoms. The curvature of the simulated calibration curves changes with sampling depth because the effects of particle vaporization and analyte diffusion on the ICP-MS intensity are dependent on the residence time of the particle in the ICP. Calibration curves of four hypothetical particles representing the four combinations of high and low boiling points (2000 and 4000 K) and high and low analyte diffusion rates (atomic masses of 10 and 200 Da) were calculated to further illustrate the relative effects of particle vaporization and analyte diffusion. The simulated calibration curves show that the sensitivity of single-particle ICP-MS is smaller than that of the ICP-MS measurement of continuous flow of standard solutions by a factor of 2 or more. Calibration using continuous flow of standard solution is semi-quantitative at best. An

Structure of metal β-diketonates and their enthalpies of vaporization

International Nuclear Information System (INIS)

Domrachev, G.A.; Sevast'yanov, V.G.; Zakharov, L.N.; Krasnodubskaya, S.V.; AN SSSR, Moscow. Inst. Obshchej i Neorganicheskoj Khimii)

1987-01-01

Using the method of additive schemes in combinaion with the structural estimation of the degree of screening of the central atom and other elements of β-diketonate molecule while analyzing the experimental enthalpies of vaporization, the contributions of separate fragments of complexes into the enthalpy of vaporization are found. It is shown that energies of intermolecular interaction in a condensed phase of monomeric metal β-diketonates with identical substituents do not depend on the central atom type. The enthalpies of dimer dissociation in a series of rare earth dipivaloylmethanates calculated. The proposed approach is advisable fo selecting forms of metal β-diketonates, the most suitable for the purposes of deep purificaion, which are characterized by maximum chemical and physico-chemical selectivity with respect to impurities, chemical inertness to equipment material, container, etc

A low aspect ratio electrothermal gun for metal plasma vapor discharge and ceramic nanopowder production

International Nuclear Information System (INIS)

Kim, Kyoung Jin; Peterson, Dennis R.

2008-01-01

Traditionally, the electrothermal gun design has the bore of a large aspect ratio: however, a low aspect ratio design with a shorter bore length has been employed for efficient production of metal plasma vapors and synthesis of nanomaterials. In a comparison of the arc resistance-current relationship, a low aspect ratio design is found to exhibit distinctively different characteristics compared to a high aspect ratio design, and this trend is explained by the scaling law of plasma properties including theory of plasma electrical conductivity. A one-dimensional isothermal model has been applied to the present experiments to confirm the scaling laws, and it was found that the present modification of the electrothermal gun is able to produce fully ionized metal plasma vapor, while the plasma vapor produced in a conventional design is partially ionized. Also, by reacting metal plasma vapors with the controlled gases in the reaction chamber, nanoscale materials such as aluminum oxide, aluminum nitride, and titanium oxide were synthesized successfully

Mechanical properties of vapor-deposited thin metallic films: a status report

International Nuclear Information System (INIS)

Adler, P.H.

1982-01-01

The mechanical properties of vapor-deposited thin metallic films are being studied in conjunction with the target fabrication group associated with the laser-fusion energy program. The purpose of the work is to gain an understanding as to which metals are structurally best suited to contain a glass microsphere filled with deuterium-tritium (D-T) gas at large internal pressures

Metal halides vapor lasers with inner reactor and small active volume.

Science.gov (United States)

Shiyanov, D. V.; Sukhanov, V. B.; Evtushenko, G. S.

2018-04-01

Investigation of the energy characteristics of copper, manganese, lead halide vapor lasers with inner reactor and small active volume 90 cm3 was made. The optimal operating pulse repetition rates, temperatures, and buffer gas pressure for gas discharge tubes with internal and external electrodes are determined. Under identical pump conditions, such systems are not inferior in their characteristics to standard metal halide vapor lasers. It is shown that the use of a zeolite halogen generator provides lifetime laser operation.

Chemical vapor deposition of refractory metals and ceramics III

International Nuclear Information System (INIS)

Gallois, B.M.; Lee, W.Y.; Pickering, M.A.

1995-01-01

The papers contained in this volume were originally presented at Symposium K on Chemical Vapor Deposition of Refractory Metals and Ceramics III, held at the Fall Meeting of the Materials Research Society in Boston, Massachusetts, on November 28--30, 1994. This symposium was sponsored by Morton International Inc., Advanced Materials, and by The Department of Energy-Oak Ridge National Laboratory. The purpose of this symposium was to exchange scientific information on the chemical vapor deposition (CVD) of metallic and ceramic materials. CVD technology is receiving much interest in the scientific community, in particular, to synthesize new materials with tailored chemical composition and physical properties that offer multiple functionality. Multiphase or multilayered films, functionally graded materials (FGMs), ''smart'' material structures and nanocomposites are some examples of new classes of materials being produced via CVD. As rapid progress is being made in many interdisciplinary research areas, this symposium is intended to provide a forum for reporting new scientific results and addressing technological issues relevant to CVD materials and processes. Thirty four papers have been processed separately for inclusion on the data base

Metal components analysis of metallothionein-III in the brain sections of metallothionein-I and metallothionein-II null mice exposed to mercury vapor with HPLC/ICP-MS

Energy Technology Data Exchange (ETDEWEB)

Kameo, Satomi; Nakai, Kunihiko; Kurokawa, Naoyuki; Satoh, Hiroshi [Tohoku University, Graduate School of Medicine, Aoba-ku, Sendai (Japan); Kanehisa, Tomokazu; Naganuma, Akira [Tohoku University, Graduate School of Pharmaceutical Sciences, Sendai (Japan)

2005-04-01

Mercury vapor is effectively absorbed via inhalation and easily passes through the blood-brain barrier; therefore, mercury poisoning with primarily central nervous system symptoms occurs. Metallothionein (MT) is a cysteine-rich metal-binding protein and plays a protective role in heavy-metal poisoning and it is associated with the metabolism of trace elements. Two MT isoforms, MT-I and MT-II, are expressed coordinately in all mammalian tissues, whereas MT-III is a brain-specific member of the MT family. MT-III binds zinc and copper physiologically and is seemed to have important neurophysiological and neuromodulatory functions. The MT functions and metal components of MTs in the brain after mercury vapor exposure are of much interest; however, until now they have not been fully examined. In this study, the influences of the lack of MT-I and MT-II on mercury accumulation in the brain and the changes of zinc and copper concentrations and metal components of MTs were examined after mercury vapor exposure by using MT-I, II null mice and 129/Sv (wild-type) mice as experimental animals. MT-I, II null mice and wild-type mice were exposed to mercury vapor or an air stream for 2 h and were killed 24 h later. The brain was dissected into the cerebral cortex, the cerebellum, and the hippocampus. The concentrations of mercury in each brain section were determined by cold vapor atomic absorption spectrometry. The concentrations of mercury, copper, and zinc in each brain section were determined by inductively coupled plasma mass spectrometry (ICP-MS). The mercury accumulated in brains after mercury vapor exposure for MT-I, II null mice and wild-type mice. The mercury levels of MT-I, II null mice in each brain section were significantly higher than those of wild-type mice after mercury vapor exposure. A significant change of zinc concentrations with the following mercury vapor exposure for MT-I, II null mice was observed only in the cerebellum analyzed by two-way analysis of

Wireless Metal Detection and Surface Coverage Sensing for All-Surface Induction Heating

Directory of Open Access Journals (Sweden)

Veli Tayfun Kilic

2016-03-01

Full Text Available All-surface induction heating systems, typically comprising small-area coils, face a major challenge in detecting the presence of a metallic vessel and identifying its partial surface coverage over the coils to determine which of the coils to power up. The difficulty arises due to the fact that the user can heat vessels made of a wide variety of metals (and their alloys. To address this problem, we propose and demonstrate a new wireless detection methodology that allows for detecting the presence of metallic vessels together with uniquely sensing their surface coverages while also identifying their effective material type in all-surface induction heating systems. The proposed method is based on telemetrically measuring simultaneously inductance and resistance of the induction coil coupled with the vessel in the heating system. Here, variations in the inductance and resistance values for an all-surface heating coil loaded by vessels (made of stainless steel and aluminum at different positions were systematically investigated at different frequencies. Results show that, independent of the metal material type, unique identification of the surface coverage is possible at all freqeuncies. Additionally, using the magnitude and phase information extracted from the coupled coil impedance, unique identification of the vessel effective material is also achievable, this time independent of its surface coverage.

Charge transfer between hydrogen(deuterium) ions and atoms in metal vapors

International Nuclear Information System (INIS)

Alvarez T, I.; Cisneros G, C.

1981-01-01

The current state of the experiments on charge transfer between hydrogen (deuterium) ions and atoms in metal vapors are given. Emphasis is given to describing different experimental techniques. The results of calculations if available, are compared with existing experimental data. (author)

Ultra high frequency induction welding of powder metal compacts

Energy Technology Data Exchange (ETDEWEB)

Cavdar, U.; Gulsahin, I.

2014-10-01

The application of the iron based Powder Metal (PM) compacts in Ultra High Frequency Induction Welding (UHFIW) were reviewed. These PM compacts are used to produce cogs. This study investigates the methods of joining PM materials enforceability with UHFIW in the industry application. Maximum stress and maximum strain of welded PM compacts were determined by three point bending and strength tests. Microhardness and microstructure of induction welded compacts were determined. (Author)

Ultra high frequency induction welding of powder metal compacts

International Nuclear Information System (INIS)

Cavdar, U.; Gulsahin, I.

2014-01-01

The application of the iron based Powder Metal (PM) compacts in Ultra High Frequency Induction Welding (UHFIW) were reviewed. These PM compacts are used to produce cogs. This study investigates the methods of joining PM materials enforceability with UHFIW in the industry application. Maximum stress and maximum strain of welded PM compacts were determined by three point bending and strength tests. Microhardness and microstructure of induction welded compacts were determined. (Author)

The Corrosion Protection of Metals by Ion Vapor Deposited Aluminum

Science.gov (United States)

Danford, M. D.

1993-01-01

A study of the corrosion protection of substrate metals by ion vapor deposited aluminum (IVD Al) coats has been carried out. Corrosion protection by both anodized and unanodized IVD Al coats has been investigated. Base metals included in the study were 2219-T87 Al, 7075-T6 Al, Titanium-6 Al-4 Vanadium (Ti-6Al-4V), 4130 steel, D6AC steel, and 4340 steel. Results reveal that the anodized IVD Al coats provide excellent corrosion protection, but good protection is also achieved by IVD Al coats that have not been anodized.

Theoretical study of adsorption of water vapor on surface of metallic uranium

CERN Document Server

Xiong Bi Tao; Xue Wei Dong; Zhu Zheng He; Jiang Gang; Wang Hong Yan; Gao Tao

2002-01-01

According to the experimental data, there is an intermediate substance that formed in the initial stage of oxidation reaction when water vapor is absorbed onto the metallic uranium. The minimum energy of UOH sub 2 witch C sub 2 subupsilon configuration is obtained in the state of sup 5 A sub 1 by B3LYP method of the density function theory (DFT), which is consistent with that by statics of atoms and molecules reaction (AMRS) and group theory. The results from calculations indicate that the adsorption of water vapor on the metallic uranium is an exothermic reaction and that the adsorbed amount decreases with the elevated temperatures. The adsorptive heat at 1 atm is -205.4747 kJ centre dot mol sup - sup 1 , which indicates a typical chemical adsorption

Ultra high frequency induction welding of powder metal compacts

Directory of Open Access Journals (Sweden)

Çavdar, Uǧur

2014-06-01

Full Text Available The application of the iron based Powder Metal (PM compacts in Ultra High Frequency Induction Welding (UHFIW were reviewed. These PM compacts are used to produce cogs. This study investigates the methods of joining PM materials enforceability with UHFIW in the industry application. Maximum stress and maximum strain of welded PM compacts were determined by three point bending and strength tests. Microhardness and microstructure of induction welded compacts were determined.Soldadura por inducción de ultra alta frecuencia de polvos de metal compactados. Se ha realizado un estudio de la aplicación de polvos de metal (PM de base hierro compactados por soldadura por inducción de ultra alta frecuencia (UHFIW. Estos polvos de metal compactados se utilizan para producir engranajes. Este estudio investiga los métodos de uni.n de los materiales de PM con UHFIW en su aplicación en la industria. La máxima tensión y la máxima deformación de los polvos de metal compactados soldados fueron determinadas por flexión en tres puntos y prueba de resistencia. Se determinó la microdureza y la microestructura de los polvos compactados por soldadura por inducción.

Thomson scattering diagnostics of steady state and pulsed welding processes without and with metal vapor

International Nuclear Information System (INIS)

Kühn-Kauffeldt, M; Schein, J; Marqués, J-L

2015-01-01

Thomson scattering is applied to measure temperature and density of electrons in the arc plasma of the direct current gas tungsten arc welding (GTAW) process and pulsed gas metal arc welding (GMAW) process. This diagnostic technique allows to determine these plasma parameters independent from the gas composition and heavy particles temperature. The experimental setup is adapted to perform measurements on stationary as well as transient processes. Spatial and temporal electron temperature and density profiles of a pure argon arc in the case of the GTAW process and argon arc with the presence of aluminum metal vapor in the case of the GMAW process were obtained. Additionally the data is used to estimate the concentration of the metal vapor in the GMAW plasma. (fast track communication)

Experimental and theoretical studies of metal vapor atoms

International Nuclear Information System (INIS)

Whitfield, S.B.; Wehlitz, Ralf; Martins, Michael

2004-01-01

Employing electron spectrometry in conjunction with tuneable synchrotron radiation, we will present a detailed examination of the photoionization dynamics of selected metal vapor atoms. In particular, this paper will focus on the relative partial cross sections of the atomic Li K-shell main and satellite (ionization with excitation) photoelectron lines in the region of the strong 1snln'l' autoionizing transitions, the atomic Sc 3d, 4s main and satellite photoelectron lines in the region of the 3p→3d giant resonance, and also the atomic Fe 3d, 4s main and satellite photoelectron lines in the same resonance region. Our experimental data for Sc and Fe will be compared to our state-of-the-art calculations based on the superposition of configuration method developed by Cowan (The Theory of Atomic Structure and Spectra. University of California Berkeley Press, Berkeley and Los Angeles, 1981). Our partial cross section measurements for Li and Sc will be complemented with measurements of the angular distribution parameter, β. In addition, our Li data will also be compared with recent R-matrix calculations (Phys. Rev. 57 (1998) 1045). In the case of Fe, we will also address the term dependent behavior of the partial cross sections on resonance. These results will highlight what can be achieved with today's technology and point the way towards future endeavors in the study of the photoionization dynamics of open-shell metal vapor atoms

Cross sections and equilibrium fractions of deuterium ions and atoms in metal vapors. Progress report, June 1, 1978-May 31, 1979

International Nuclear Information System (INIS)

Morgan, T.J.

1979-01-01

The purpose of this program is to measure cross sections and equilibrium fractions of deuterium ions and atoms in metal vapors. In particular, in connection with double charge exchange D - ion sources, there is concern with D - formation in alkaline-earth vapor targets. Also, in connection with possible metal vapor contamination in the system, there is concern with cross sections for high energy D + , D 0 and D - collisions with these metal vapors. Results from this research will fill in a gap in knowledge of single and double charge transfer and multiple collision processes in alkaline-earth targets and provide a better understanding of D - formation mechanisms. A list of publications is included. 6 references

Apoptosis induction in human lymphocytes after in vitro exposure to cobalt/hard metal compounds

International Nuclear Information System (INIS)

Boeck, M. de; Decordier, I.; Lombaert, N.; Cundari, E.; Kirsch-Volders, M.; Lison, D.

2001-01-01

Full text: An increased risk of lung cancer is associated with occupational exposure to mixtures of cobalt metal (Co) and tungsten carbide (WC) particles, but apparently not when exposure is to cobalt alone. The mechanism for this increased cancer risk is not fully understood. The evaluation of the in vitro genotoxic effects in lymphocytes exposed to varying cobalt species demonstrated that the WC-Co hard metal mixture is more genotoxic (DNA damage, chromosome/genome mutations) than metallic Co alone. WC alone was not genotoxic. Thus, WC-Co represents a specific (geno)toxic entity. In order to assess the survival of human lymphocytes after in vitro exposure to metallic Co, CoCl 2 , WC and the WC-Co mixture, two apoptosis/necrosis detection methods were applied (annexin V staining and flow cytometry). Annexin-V staining of early apoptotic cells demonstrated a dose- and time dependent induction of apoptosis by metallic Co, CoCl 2 , WC and the WC-Co mixture. The time course of the process varied according to the metal species tested. Metallic Co and CoCl 2 caused a gradually increasing frequency of apoptotic cells with time (up to 24 h). WC-induced apoptosis displayed a typical 6 hour peak, which was not the case for the WC-Co mixture or for Co. Apoptosis induction by the WC-Co mixture was intermediate between that induced by Co and WC separately. Analysis of propidium iodide stained cells by flow cytometry was performed as a later marker for apoptosis induction. Preliminary data indicate similar tendencies of apoptosis induction as those detected by annexin-V. Identification of the apoptotic pathway triggered by the metal compounds was studied by inhibition of the ceramide-apoptosis pathway by fumonisin causing reduction of apoptosis induction for all compounds, but strongest after 6 hour exposure to WC. The use of specific caspase inhibitors will allow to further elucidate the different pathways involved. The current data demonstrating in vitro the apoptosis

Apoptosis induction in human lymphocytes after in vitro exposure to cobalt/hard metal compounds

Energy Technology Data Exchange (ETDEWEB)

Boeck, M de; Decordier, I; Lombaert, N; Cundari, E; Kirsch-Volders, M [Vrije Universiteit Brussel, Laboratorium voor Cellulaire Genetica, Brussel (Belgium); Lison, D [Universite catholique de Louvain, Unite de Toxicologie industrielle et Medecine du Travail, Bruxelles (Belgium)

2001-07-01

Full text: An increased risk of lung cancer is associated with occupational exposure to mixtures of cobalt metal (Co) and tungsten carbide (WC) particles, but apparently not when exposure is to cobalt alone. The mechanism for this increased cancer risk is not fully understood. The evaluation of the in vitro genotoxic effects in lymphocytes exposed to varying cobalt species demonstrated that the WC-Co hard metal mixture is more genotoxic (DNA damage, chromosome/genome mutations) than metallic Co alone. WC alone was not genotoxic. Thus, WC-Co represents a specific (geno)toxic entity. In order to assess the survival of human lymphocytes after in vitro exposure to metallic Co, CoCl{sub 2}, WC and the WC-Co mixture, two apoptosis/necrosis detection methods were applied (annexin V staining and flow cytometry). Annexin-V staining of early apoptotic cells demonstrated a dose- and time dependent induction of apoptosis by metallic Co, CoCl{sub 2}, WC and the WC-Co mixture. The time course of the process varied according to the metal species tested. Metallic Co and CoCl{sub 2} caused a gradually increasing frequency of apoptotic cells with time (up to 24 h). WC-induced apoptosis displayed a typical 6 hour peak, which was not the case for the WC-Co mixture or for Co. Apoptosis induction by the WC-Co mixture was intermediate between that induced by Co and WC separately. Analysis of propidium iodide stained cells by flow cytometry was performed as a later marker for apoptosis induction. Preliminary data indicate similar tendencies of apoptosis induction as those detected by annexin-V. Identification of the apoptotic pathway triggered by the metal compounds was studied by inhibition of the ceramide-apoptosis pathway by fumonisin causing reduction of apoptosis induction for all compounds, but strongest after 6 hour exposure to WC. The use of specific caspase inhibitors will allow to further elucidate the different pathways involved. The current data demonstrating in vitro the

An approach to calculating metal particle detection in lubrication oil based on a micro inductive sensor

Science.gov (United States)

Wu, Yu; Zhang, Hongpeng

2017-12-01

A new microfluidic chip is presented to enhance the sensitivity of a micro inductive sensor, and an approach to coil inductance change calculation is introduced for metal particle detection in lubrication oil. Electromagnetic knowledge is used to establish a mathematical model of an inductive sensor for metal particle detection, and the analytic expression of coil inductance change is obtained by a magnetic vector potential. Experimental verification is carried out. The results show that copper particles 50-52 µm in diameter have been detected; the relative errors between the theoretical and experimental values are 7.68% and 10.02% at particle diameters of 108-110 µm and 50-52 µm, respectively. The approach presented here can provide a theoretical basis for an inductive sensor in metal particle detection in oil and other areas of application.

Electric conductivity of alkali metal vapors in the region of critical point

International Nuclear Information System (INIS)

Likal'ter, A.A.

1982-01-01

A behaviour of alkali metal conductivity in the vicinity of a critical point has been analyzed on the base of deVeloped representations on a vapor state. A phenomenological conductivity theory has been developed, which is in a good agreement with experimental data obtained

Modeling film uniformity and symmetry in ionized metal physical vapor deposition with cylindrical targets

International Nuclear Information System (INIS)

Lu Junqing; Yang Lin; Yoon, Jae Hong; Cho, Tong Yul; Tao Guoqing

2008-01-01

Severe asymmetry of the metal deposits on the trench sidewalls occurs near the wafer edge during low pressure ionized metal physical vapor deposition of Cu seed layer for microprocessor interconnects. To investigate this process and mitigate the asymmetry, an analytical view factor model based on the analogy between metal sputtering and diffuse thermal radiation was constructed to investigate deposition uniformity and symmetry for cylindrical target sputtering in low pressure (below 0.1 Pa) ionized Cu physical vapor deposition. The model predictions indicate that as the distance from the cylindrical target to wafer increases, the metal film thickness becomes more uniform across the wafer and the asymmetry of the metal deposits at the wafer edge increases significantly. These trends are similar to those for planar targets. To minimize the asymmetry, the height of the cylindrical target should be kept at a minimum. For cylindrical targets, the outward-facing sidewall of the trench could receive more direct Cu fluxes than the inward-facing one when the target to wafer distance is short. The predictions also indicate that increasing the diameter of the cylindrical target could significantly reduce the asymmetry in metal deposits at the wafer edge and make the film thickness more uniform across the wafer

Application of Discharges in Vapor of Evaporated Metals for the Film Deposition from the Ionized Stream

International Nuclear Information System (INIS)

Kostin, E.G.

2006-01-01

results of researches of the discharge device for ionization of the vapor of solid materials are presented. Evaporation of a material was made by an electron gun with a deviation of a beam on 180 degree. Diode type discharge device for ionization was placed above a surface of evaporated metal and was in a longitudinal adjustable magnetic field. Discharge was carried out in crossed electric and magnetic fields. Partial ionization of the vapor was made by primary and secondary electrons of the gun in a vapor cloud above evaporated substance. Physical properties and structure of the films. The comparative analysis of the films properties, besieged in conditions of influence of bombardment by ions of evaporated metal were studied depending on energy and the contents of ions in a stream of particles on a substrate

The theory of temporal compression of intense pulses in a metal vapor

Energy Technology Data Exchange (ETDEWEB)

Shaw, M.J.; Crane, J.K.

1990-11-16

We examine compression of near-resonant pulses in metal vapor in the nonlinear regime. Our calculations examine nonlinear effects on compression of optimally-chirped pulses of various fluences. In addition, we compare model predictions with experimental results for compression of 4 nsec Nd:YAG pumped dye pulses.

Catalytic activation of molecular hydrogen in alkyne hydrogenation reactions by lanthanide metal vapor reaction products

International Nuclear Information System (INIS)

Evans, W.J.; Bloom, I.; Engerer, S.C.

1983-01-01

A rotary metal vapor was used in the synthesis of Lu, Er, Nd, Sm, Yb, and La alkyne, diene, and phosphine complexes. A typical catalytic hydrogenation experiment is described. The lanthanide metal vapor product is dissolved in tetrahydrofuran or toluene and placed in a pressure reaction vessel 3-hexyne (or another substrate) is added, the chamber attached to a high vacuum line, cooled to -196 0 C, evacuated, warmed to ambient temperature and hydrogen is added. The solution is stirred magnetically while the pressure in monitored. The reaction products were analyzed by gas chromatography. Rates and products of various systems are listed. This preliminary survey indicates that catalytic reaction chemistry is available to these metals in a wide range of coordination environments. Attempts to characterize these compounds are hampered by their paramagnetic nature and their tendency to polymerize

Effect of melt surface depression on the vaporization rate of a metal heated by an electron beam

International Nuclear Information System (INIS)

Guilbaud, D.

1995-01-01

In order to produce high density vapor, a metal confined in a water cooled crucible is heated by an electron beam (eb). The energy transfer to the metal causes partial melting, forming a pool where the flow is driven by temperature induced buoyancy and capillary forces. Furthermore, when the vaporization rate is high, the free surface is depressed by the thrust of the vapor. The main objective of this paper is to analyse the combined effects of liquid flow and vapor condensation back on the liquid surface. This is done with TRIO-EF, a general purpose fluid mechanics finite element code. A suitable iterative scheme is used to calculate the free surface flow and the temperature field. The numerical simulation gives an insight about the influence of the free surface in heat transfer. The depression of the free surface induces strong effects on both liquid and vapor. As liquid is concerned, buoyancy convection in the pool is enhanced, the energy flux from electron beam is spread and constriction of heat flux under the eb spot is weakened. It results that heat transfer towards the crucible is reinforced. As vapor is concerned, its fraction that condenses back on the liquid surface is increased. These phenomena lead to a saturation of the net vaporization rate as the eb spot radius is reduced, at constant eb power. (author). 8 refs., 13 figs., 2 tabs

Recovery of Platinum Group Metals from Spent Catalysts Using Iron Chloride Vapor Treatment

Science.gov (United States)

Taninouchi, Yu-ki; Okabe, Toru H.

2018-05-01

The recovery of platinum group metals (PGMs) from spent automobile catalysts is a difficult process because of their relatively low contents in the scrap. In this study, to improve the efficiency of the existing recycling techniques, a novel physical concentration method involving treatment with FeCl2 vapor has been examined. The reactions occurring between typical catalyst components and FeCl2 vapor are discussed from the thermodynamic point of view, and the validity of the proposed technique was experimentally verified. The obtained results indicate that the vapor treatment at around 1200 K (927 °C) can effectively alloy PGMs (Pt, Pd, and Rh) with Fe, resulting in the formation of a ferromagnetic alloy. It was also confirmed that cordierite and alumina (the major catalyst components) remained unreacted after the vapor treatment, while ceria species were converted into oxychlorides. The samples simulating the automobile catalyst were also subjected to magnetic separation after the treatment with FeCl2 vapor; as a result, PGMs were successfully extracted and concentrated in the form of a magnetic powder. Thus, the FeCl2 vapor treatment followed by magnetic separation can be utilized for recovering PGMs directly from spent catalysts as an effective pretreatment for the currently used recycling methods.

Optimization of a single-drop microextraction method for multielemental determination by electrothermal vaporization inductively coupled plasma mass spectrometry following in situ vapor generation

International Nuclear Information System (INIS)

Gil, Sandra; Loos-Vollebregt, Margaretha T.C. de; Bendicho, Carlos

2009-01-01

A headspace single-drop microextraction (HS-SDME) method has been developed in combination with electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) for the simultaneous determination of As, Sb, Bi, Pb, Sn and Hg in aqueous solutions. Vapor generation is carried out in a 40 mL volume closed-vial containing a solution with the target analytes in hydrochloric acid and potassium ferricyanide medium. Hydrides (As, Sb, Bi, Pb, Sn) and Hg vapor are trapped onto an aqueous single drop (3 μL volume) containing Pd(II), followed by the subsequent injection in the ETV. Experimental variables such as medium composition, sodium tetrahydroborate (III) volume and concentration, stirring rate, extraction time, sample volume, ascorbic acid concentration and palladium amount in the drop were fully optimized. The limits of detection (LOD) (3σ criterion) of the proposed method for As, Sb, Bi, Pb, Sn and Hg were 0.2, 0.04, 0.01, 0.07, 0.09 and 0.8 μg/L, respectively. Enrichment factors of 9, 85, 138, 130, 37 and 72 for As, Sb, Bi, Pb, Sn and Hg, respectively, were achieved in 210 s. The relative standard deviations (N = 5) ranged from 4 to 8%. The proposed HS-SDME-ETV-ICP-MS method has been applied for the determination of As, Sb, Bi, Pb, Sn and Hg in NWRI TM-28.3 certified reference material.

Scoping studies of vapor behavior during a severe accident in a metal-fueled reactor

International Nuclear Information System (INIS)

Spencer, B.W.; Marchaterre, J.F.

1985-01-01

Scoping calculations have been performed examining the consequences of fuel melting and pin failures for a reactivity-insertion type accident in a sodium-cooled, pool-type reactor fueled with a metal alloy fuel. The principal gas and vapor species released are shown to be Xe, Cs,and bond sodium contained within the fuel porosity. Fuel vapor pressure is insignificant, and there is no energetic fuel-coolant interaction for the conditions considered. Condensation of sodium vapor as it expands into the upper sodium pool in a jet mixing regime may occur as rapidly as the vapor emerges from the disrupted core (although reactor-material experiments are needed to confirm these high condensation rates). If the predictions of rapid direct-contact condensation can be verified experimentally for the sodium system, the implication is that the ability of vapor expansion to perform appreciable work on the system is largely eliminated. Furthermore, the ability of an expanding vapor bubble to transport fuel and fission product species to the cover gas region where they may be released to the containment is also largely eliminated. The radionuclide species except for fission gas are largely retained within the core and sodium pool

Using laser absorption spectroscopy to monitor composition and physical properties of metal vapors

International Nuclear Information System (INIS)

Berzins, L.V.

1993-01-01

The Atomic Vapor Laser Isotope Separation (AVLIS) program has been using laser absorption spectroscopy to monitor vapor densities for over 15 years. Laser absorption spectroscopy has proven itself to be an accurate and reliable method to monitor both density and composition. During this time the diagnostic has moved from a research tool toward a robust component of a process control system. The hardware used for this diagnostic is discussed elsewhere at this symposium. This paper describes how the laser absorption spectroscopy diagnostic is used as a component of a process control system as well as supplying detailed measurements on vapor densities, composition, flow velocity, internal and kinetic temperatures, and constituent distributions. Examples will be drawn from the uranium AVLIS program. In addition potential applications such as composition control in the production of metal matrix composites or aircraft alloys will be discussed

High temperature vapor pressures of stainless steel type 1.4970 and of some other pure metals from laser evaporation

International Nuclear Information System (INIS)

Bober, M.; Singer, J.

1984-10-01

For the safety analysis of nuclear reactors vapor pressure data of stainless steel are required up to temperatures exceeding 4000 K. In analogy to the classic boiling point method a new technique was developed to measure the high-temperature vapor pressures of stainless steel and other metals from laser vaporization. A fast pyrometer, an ion current probe and an image converter camera are used to detect incipient boiling from the time-temperature curve. The saturated-vapor pressure curves of stainless steel (Type 1.4970), being a cladding material of the SNR 300 breeder reactor, and of molybdenum are experimentally determined in the temperature ranges of 2800-3900 K and 4500-5200 K, respectively. The normal boiling points of iron, nickel, titanium, vanadium and zirconium are verified. Besides, spectral emissivity values of the liquid metals are measured at the pyrometer wavelengths of 752 nm and/or 940 nm. (orig.) [de

Improving visibility of rear surface cracks during inductive thermography of metal plates using Autoencoder

Science.gov (United States)

Xie, Jing; Xu, Changhang; Chen, Guoming; Huang, Weiping

2018-06-01

Inductive thermography is one kind of infrared thermography (IRT) technique, which is effective in detection of front surface cracks in metal plates. However, rear surface cracks are usually missed due to their weak indications during inductive thermography. Here we propose a novel approach (AET: AE Thermography) to improve the visibility of rear surface cracks during inductive thermography by employing the Autoencoder (AE) algorithm, which is an important block to construct deep learning architectures. We construct an integrated framework for processing the raw inspection data of inductive thermography using the AE algorithm. Through this framework, underlying features of rear surface cracks are efficiently extracted and new clearer images are constructed. Experiments of inductive thermography were conducted on steel specimens to verify the efficacy of the proposed approach. We visually compare the raw thermograms, the empirical orthogonal functions (EOFs) of the prominent component thermography (PCT) technique and the results of AET. We further quantitatively evaluated AET by calculating crack contrast and signal-to-noise ratio (SNR). The results demonstrate that the proposed AET approach can remarkably improve the visibility of rear surface cracks and then improve the capability of inductive thermography in detecting rear surface cracks in metal plates.

Heteroepitaxial growth of 3-5 semiconductor compounds by metal-organic chemical vapor deposition for device applications

Science.gov (United States)

Collis, Ward J.; Abul-Fadl, Ali

1988-01-01

The purpose of this research is to design, install and operate a metal-organic chemical vapor deposition system which is to be used for the epitaxial growth of 3-5 semiconductor binary compounds, and ternary and quaternary alloys. The long-term goal is to utilize this vapor phase deposition in conjunction with existing current controlled liquid phase epitaxy facilities to perform hybrid growth sequences for fabricating integrated optoelectronic devices.

Induction melting for volume reduction of metallic TRU wastes

International Nuclear Information System (INIS)

Westsik, J.H. Jr.; Montgomery, D.R.; Katayama, Y.B.; Ross, W.A.

1986-01-01

Volume reduction of metallic transuranic wastes offers economic and safety incentives for treatment of wastes generated at a hypothetical commercial fuel reprocessing facility. Induction melting has been identified as the preferred process for volume reduction of spent fuel hulls, fuel assembly hardware, and failed equipment from a reprocessing plant. Bench-scale melting of Zircaloy and stainless steel mixtures has been successfully conducted in a graphite crucible inside a large vacuum chamber. A low-melting-temperature alloy forms that has demonstrated excellent leach resistance. The alloy can be used to encapsulate other metallic wastes that cannot be melted using the existing equipment design

Vapor-Phase Deposition and Modification of Metal-Organic Frameworks: State-of-the-Art and Future Directions.

Science.gov (United States)

Stassen, Ivo; De Vos, Dirk; Ameloot, Rob

2016-10-04

Materials processing, and thin-film deposition in particular, is decisive in the implementation of functional materials in industry and real-world applications. Vapor processing of materials plays a central role in manufacturing, especially in electronics. Metal-organic frameworks (MOFs) are a class of nanoporous crystalline materials on the brink of breakthrough in many application areas. Vapor deposition of MOF thin films will facilitate their implementation in micro- and nanofabrication research and industries. In addition, vapor-solid modification can be used for postsynthetic tailoring of MOF properties. In this context, we review the recent progress in vapor processing of MOFs, summarize the underpinning chemistry and principles, and highlight promising directions for future research. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Experimental and theoretical investigations about the vaporization of laser-produced aerosols and individual particles inside inductively-coupled plasmas — Implications for the extraction efficiency of ions prior to mass spectrometry

International Nuclear Information System (INIS)

Flamigni, Luca; Koch, Joachim; Günther, Detlef

2012-01-01

Current quantification capabilities of laser ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS) are known to be restricted by elemental fractionation as a result of LA-, transport-, and ICP-induced effects which, particularly, may provoke inaccuracies whenever calibration strategies on the basis of non-matrix matched standard materials are applied. The present study is dealing with the role of ICP in this complex scenario. Therefore, the vaporization process of laser-produced aerosols and subsequent diffusion losses occurring inside ICP sources were investigated using 2-D optical emission spectrometry (OES) and ICP-quadrupole (Q)MS of individual particles. For instance, Na- and Ca-specific OES of aerosols produced by LA of silicate glasses or metals revealed axial shifts in the onset and maximum position of atomic emission which were in the range of a few millimeters. The occurrence of these shifts was found to arise from composition-dependent particle/aerosol penetration depths, i.e. the displacement of axial vaporization starting points controlling the ion extraction efficiency through the ICP-MS vacuum interface due to a delayed, diffusion-driven expansion of oxidic vs. metallic aerosols. Furthermore, ICP-QMS of individual particles resulted in 1/e half-value signal durations of approximately 100 μs, which complies with modeled values if OES maxima are assumed to coincide with positions of instantaneous vaporization and starting points for atomic diffusion. To prove phenomena observed for their consistency, in addition, “ab initio” as well as semi-empirical simulations of particle/aerosol penetration depths followed by diffusion-driven expansion was accomplished indicating differences of up to 15% in the relative ion extraction efficiency depending on whether analytes are supplied as metals or oxides. Implications of these findings on the accuracy achievable by state-of-the-art LA-ICP-MS systems are outlined. - Highlights: ► Specification

Suitable alkaline for graphene peeling grown on metallic catalysts using chemical vapor deposition

Science.gov (United States)

Karamat, S.; Sonuşen, S.; Çelik, Ü.; Uysallı, Y.; Oral, A.

2016-04-01

In chemical vapor deposition, the higher growth temperature roughens the surface of the metal catalyst and a delicate method is necessary for the transfer of graphene from metal catalyst to the desired substrates. In this work, we grow graphene on Pt and Cu foil via ambient pressure chemical vapor deposition (AP-CVD) method and further alkaline water electrolysis was used to peel off graphene from the metallic catalyst. We used different electrolytes i.e., sodium hydroxide (NaOH), potassium hydroxide (KOH), lithium hydroxide (LiOH) and barium hydroxide Ba(OH)2 for electrolysis, hydrogen bubbles evolved at the Pt cathode (graphene/Pt/PMMA stack) and as a result graphene layer peeled off from the substrate without damage. The peeling time for KOH and LiOH was ∼6 min and for NaOH and Ba(OH)2 it was ∼15 min. KOH and LiOH peeled off graphene very efficiently as compared to NaOH and Ba(OH)2 from the Pt electrode. In case of copper, the peeling time is ∼3-5 min. Different characterizations like optical microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and atomic force microscopy were done to analyze the as grown and transferred graphene samples.

Henry's Law vaporization studies and thermodynamics of einsteinium-253 metal dissolved in ytterbium

International Nuclear Information System (INIS)

Kleinschmidt, P.D.; Ward, J.W.; Matlack, G.M.; Haire, R.G.

1984-01-01

The cohesive energy of metallic einsteinium determines whether einsteinium is a trivalent or divalent metal. The enthalpy of sublimation, a measure of the cohesive energy, is calculated from the partial pressures of einsteinium over an alloy. The partial pressure of 253 Es has been measured over the range 470--870 K, using combined target and mass spectrometric Knudsen effusion techniques. An alloy was prepared with einsteinium dissolved in a ytterbium solvent to produce a very dilute solution. Partial pressure measurements on the alloy were amenable to the experimental technique and a data analysis using a Henry's law treatment of the data. Vapor pressure data are combined with an estimated crystal entropy S 0 298 and ΔC 0 /sub p/ for ytterbium, to produce enthalpy, entropy, and free energy functions from 298 to 1300 K. The vapor pressure of einsteinium in a dilute einsteinium--ytterbium alloy is described by the equation log P(atm) = -(6815 +- 216)/T+2.576 +- 0.337, from which we calculate for the enthalpy of sublimation of pure einsteinium ΔH 0 298 (second law) = 31.76 kcal/mol. The value of the enthalpy of sublimation is consistent with the conclusion that Es is a divalent metal

Metal vapor micro-jet controls material redistribution in laser powder bed fusion additive manufacturing

OpenAIRE

Ly, Sonny; Rubenchik, Alexander M.; Khairallah, Saad A.; Guss, Gabe; Matthews, Manyalibo J.

2017-01-01

The results of detailed experiments and finite element modeling of metal micro-droplet motion associated with metal additive manufacturing (AM) processes are presented. Ultra high speed imaging of melt pool dynamics reveals that the dominant mechanism leading to micro-droplet ejection in a laser powder bed fusion AM is not from laser induced recoil pressure as is widely believed and found in laser welding processes, but rather from vapor driven entrainment of micro-particles by an ambient gas...

A study on vapor explosions

International Nuclear Information System (INIS)

Takagi, N.; Shoji, M.

1979-01-01

An experimental study was carried out for vapor explosions of molten tin falling in water. For various initial metal temperatures and subcooling of water, transient pressure of the explosions, relative frequency of the explosions and the position where the explosions occur were measured in detail. The influence of ambient pressure was also investigated. From the results, it was concluded that the vapor explosion is closely related to the collapse of a vapor film around the molten metal. (author)

Mutual inductance appliance for measuring the level of a molten metal

International Nuclear Information System (INIS)

Zbinden, Marc.

1982-01-01

The invention concerns an appliance for measuring the level of a molten metal of the kind using the variation of the mutual inductance between two imbricated windings depending on the level of the free area of the molten metal in the range of levels taken up by the windings. It has a particularly significant use in measuring the level of liquid sodium, especially in nuclear facilities where sodium is used as coolant [fr

High index of refraction films for dielectric mirrors prepared by metal-organic chemical vapor deposition

International Nuclear Information System (INIS)

Brusasco, R.M.

1989-01-01

A wide variety of metal oxides with high index of refraction can be prepared by Metal-Organic Chemical Vapor Deposition. We present some recent optical and laser damage results on oxide films prepared by MOCVD which could be used in a multilayer structure for highly reflecting (HR) dielectric mirror applications. The method of preparation affects both optical properties and laser damage threshold. 10 refs., 8 figs., 4 tabs

Acceleration of Vaporization, Atomization, and Ionization Efficiencies in Inductively Coupled Plasma by Merging Laser-Ablated Particles with Hydrochloric Acid Gas.

Science.gov (United States)

Nakazawa, Takashi; Izumo, Saori; Furuta, Naoki

2016-01-01

To accelerate the vaporization, atomization, and ionization efficiencies in laser ablation inductively coupled plasma mass spectrometry, we merged HCl gas with laser-ablated particles before introduction into the plasma, to convert their surface constituents from oxides to lower-melting chlorides. When particles were merged with HCl gas generated from a HCl solution at 200°C, the measured concentrations of elements in the particles were 135% higher on average than the concentrations in particles merged with ultrapure water vapor. Particle corrosion and surface roughness were observed by scanning electron microscopy, and oxide conversion to chlorides was confirmed by X-ray photoelectron spectroscopy. Under the optimum conditions, the recoveries of measured elements improved by 23% on average, and the recoveries of elements with high-melting oxides (Sr, Zr, and Th) improved by as much as 36%. These results indicate that vaporization, atomization, and ionization in the ICP improved when HCl gas was merged with the ablated particles.

Induction melting for volume reduction of metallic TRU wastes

International Nuclear Information System (INIS)

Westsik, J.H. Jr.; Montgomery, D.R.; Katayama, Y.B.; Ross, W.A.

1986-02-01

Volume reduction of metallic transuranic wastes offers economic and safety incentives for treatment of wastes generated at a hypothetical commercial fuel reprocessing facility. Induction melting has been identified as the preferred process for volume reduction of spent fuel hulls, fuel assembly hardware, and failed equipment from a reprocessing plant. Bench-scale melting of Zircaloy and stainless steel mixtures has been successfully conducted in a graphite crucible inside a large vacuum chamber. A low-melting-temperature alloy forms that has demonstrated excellent leach resistance. The alloy can be used to encapsulate other metallic wastes that cannot be melted using the existing equipment design. 18 refs., 4 figs., 3 tabs

Fractionation of families of major, minor, and trace metals across the melt-vapor interface in volcanic exhalations

Science.gov (United States)

Hinkley, T.K.; Le Cloarec, M.-F.; Lambert, G.

1994-01-01

Chemical families of metals fractionate systematically as they pass from a silicate melt across the interface with the vapor phase and on into a cooled volcanic plume. We measured three groups of metals in a small suite of samples collected on filters from the plumes of Kilauea (Hawaii, USA), Etna (Sicily), and Merapi (Java) volcanoes. These were the major, minor, and trace metals of the alkali and alkaline earth families (K, Rb, Cs, Ca, Sr, Ba), a group of ordinarily rare metals (Cd, Cu, In, Pb, Tl) that are related by their chalcophile affinities, and the radon daughter nuclides 210Po, 210Bi, and 210Pb. The measurements show the range and some details of systematic melt-vapor fractionation within and between these groups of metals. In the plumes of all three volcanoes, the alkali metals are much more abundant than the alkaline earth metals. In the Kilauea plume, the alkali metals are at least six times more abundant than the alkaline earth metals, relative to abundances in the melt; at Etna, the factor is at least 300. Fractionations within each family are, commonly, also distinctive; in the Kilauea plume, in addition to the whole alkaline earth family being depleted, the heaviest metals of the family (Sr, Ba) are progressively more depleted than the light metal Ca. In plumes of fumaroles at Merapi, K/Cs ratios were approximately three orders of magnitude smaller than found in other earth materials. This may represent the largest observed enrichment of the "light ion lithophile" (LIL) metals. Changes in metal ratios were seen through the time of eruption in the plumes of Kilauea and Etna. This may reflect degree of degassing of volatiles, with which metals complex, from the magma bodies. At Kilauea, the changes in fractionation were seen over about three years; fractionation within the alkaline earth family increased, and that between the two families decreased, over that time. All of the ordinarily rare chalcophile metals measured are extremely abundant in

Induction apparatus monitoring structural strains in liquid-metal-cooled nuclear reactor

International Nuclear Information System (INIS)

Dean, S.A.; Evans, R.A.

1981-01-01

An improved method of monitoring induced torsional and linear strains in the internal structures of liquid metal cooled nuclear reactors is described. An electrical induction apparatus indicates the variation of magnetic coupling caused by a ferromagnetic member of the apparatus being subjected to such strains. (U.K.)

Saturated vapor pressure over molten mixtures of GaCl3 and alkali metal chlorides

International Nuclear Information System (INIS)

Salyulev, A.B.; Smolenskij, V.V.; Moskalenko, N.I.

2004-01-01

Volatilities of GaCl 3 and alkali metal chlorides over diluted (up to 3 mol %) solutions of GaCl 3 in LiCl, NaCl, KCl, RbCl, and CsCl were measured at 1100 K by dynamic and indirect static methods. Chemical composition of saturated vapor over the mixed melts was determined. Partial pressures of the components were calculated. Their values depend essentially on specific alkali metal cation and on concentration of GaCl 3 ; their variation permits altering parameters of GaCl 3 distillation from the salt melt in a wide range [ru

Comparison of plastic single-use and metal reusable laryngoscope blades for orotracheal intubation during rapid sequence induction of anesthesia.

Science.gov (United States)

Amour, Julien; Marmion, Frédéric; Birenbaum, Aurélie; Nicolas-Robin, Armelle; Coriat, Pierre; Riou, Bruno; Langeron, Olivier

2006-01-01

Plastic single-use laryngoscope blades are inexpensive and carry a lower risk of infection compared with metal reusable blades, but their efficiency during rapid sequence induction remains a matter of debate. The authors therefore compared plastic and metal blades during rapid sequence induction in a prospective randomized trial. Two hundred eighty-four adult patients undergoing general anesthesia requiring rapid sequence induction were randomly assigned on a weekly basis to either plastic single-use or reusable metal blades (cluster randomization). After induction, a 60-s period was allowed to complete intubation. In the case of failed intubation, a second attempt was performed using metal blade. The primary endpoint of the study was the rate of failed intubations, and the secondary endpoint was the incidence of complications (oxygen desaturation, lung aspiration, and oropharynx trauma). Both groups were similar in their main characteristics, including risk factors for difficult intubation. On the first attempt, the rate of failed intubation was significantly increased in plastic blade group (17 vs. 3%; P < 0.01). In metal blade group, 50% of failed intubations were still difficult after the second attempt. In plastic blade group, all initial failed intubations were successfully intubated using metal blade, with an improvement in Cormack and Lehane grade. There was a significant increase in the complication rate in plastic group (15 vs. 6%; P < 0.05). In rapid sequence induction of anesthesia, the plastic laryngoscope blade is less efficient than a metal blade and thus should not be recommended for use in this clinical setting.

Collision cross sections and equilibrium fractions of ions and atoms in metal vapor targets. Project progress report, June 1, 1979-May 31, 1980

International Nuclear Information System (INIS)

Morgan, T.J.

1980-01-01

The objective of this program is to measure atomic collision cross sections and equilibrium fractions of ions and atoms in metal vapor targets. The goal is to obtain experimental information on atomic collision processes relevant to the Magnetic Fusion Energy Program. In particular, in connection with the development of double charge exchange D - ion sources, we are measuring D - formation cross sections in alkaline-earth metal vapor targets. During the period covered in this report we have measured electron transfer cross sections for 3-40 keV D + ions and D 0 atoms in collision with calcium vapor

Determination of Cu, Mn, Ni and Sn in gasoline by electrothermal vaporization inductively coupled plasma mass spectrometry, and emulsion sample introduction

International Nuclear Information System (INIS)

Saint'Pierre, Tatiana D.; Dias, Lucia Felicidade; Pozebon, Dirce; Aucelio, Ricardo Q.; Curtius, Adilson J.; Welz, Bernhard

2002-01-01

Trace metals in fuels, except in the case of additives, are usually undesirable and normally they occur in very low concentrations in gasoline, requiring sensitive techniques for their determination. Coupling of electrothermal vaporization with inductively coupled plasma mass spectrometry minimizes the problems related to the introduction of organic solvents into the plasma. Furthermore, sample preparation as oil-in-water emulsions reduces problems related to gasoline analysis. In this work, a method for determination of Cu, Mn, Ni and Sn in gasoline is proposed. Samples were prepared by forming a 10-fold diluted emulsion with a surfactant (Triton X-100), after treatment with concentrated HNO 3 . The sample emulsion was pre-concentrated in the graphite tube by repeated pipetting and drying. External calibration was used with aqueous standards in a purified gasoline emulsion. Six samples from different gas stations were analyzed, and the analyte concentrations were found to be in the μg l -1 range or below. The limits of detection were 0.22, 0.02, 0.38 and 0.03 μg l -1 for Cu, Mn, Ni and Sn, respectively. The accuracy of the method was estimated using a recovery test

Sensing and capture of toxic and hazardous gases and vapors by metal-organic frameworks.

Science.gov (United States)

Wang, Hao; Lustig, William P; Li, Jing

2018-03-13

Toxic and hazardous chemical species are ubiquitous, predominantly emitted by anthropogenic activities, and pose serious risks to human health and the environment. Thus, the sensing and subsequent capture of these chemicals, especially in the gas or vapor phase, are of extreme importance. To this end, metal-organic frameworks have attracted significant interest, as their high porosity and wide tunability make them ideal for both applications. These tailorable framework materials are particularly promising for the specific sensing and capture of targeted chemicals, as they can be designed to fit a diverse range of required conditions. This review will discuss the advantages of metal-organic frameworks in the sensing and capture of harmful gases and vapors, as well as principles and strategies guiding the design of these materials. Recent progress in the luminescent detection of aromatic and aliphatic volatile organic compounds, toxic gases, and chemical warfare agents will be summarized, and the adsorptive removal of fluorocarbons/chlorofluorocarbons, volatile radioactive species, toxic industrial gases and chemical warfare agents will be discussed.

Vapor-transport of tungsten and its geologic application

Energy Technology Data Exchange (ETDEWEB)

Shibue, Y [Hyogo Univ. of Teacher Education, Hyogo (Japan)

1988-11-10

The volatility of tungsten in a hydrous system at elevated temperatures and pressures was examined, and a tentative model for the enrichment of tungsten in hydrothermal solutions for the deposits related to granitic activities was proposed. To produce vapor-saturated solution, 17 or 15ml of 20wt% NaCl solution was introduced into an autoclave. Ca(OH){sub 2} for tungsten and H{sub 2}WO{sub 4} for base metals were used as vapor-captures, and run products were identified by X-ray powder diffractometry. The results suggested that the ratio of tungsten to base metals was higher in a vapor phase than in a liquid phase, and more enrichment of tungsten in the vapor phase occurred at higher temperature and pressure under the coexistence of the vapor and liquid phase. The tentative model emphasizing the vapor-transport of tungsten could explain the presence of tungsten deposits without large mineralization of base metals. Geological schematic model for the generation of the hydrothermal solution enriched in tungsten compared with base metals was illustrated based on above mentioned results. 21 refs., 3 figs.

Direct Growth of Graphene on Silicon by Metal-Free Chemical Vapor Deposition

Science.gov (United States)

Tai, Lixuan; Zhu, Daming; Liu, Xing; Yang, Tieying; Wang, Lei; Wang, Rui; Jiang, Sheng; Chen, Zhenhua; Xu, Zhongmin; Li, Xiaolong

2018-06-01

The metal-free synthesis of graphene on single-crystal silicon substrates, the most common commercial semiconductor, is of paramount significance for many technological applications. In this work, we report the growth of graphene directly on an upside-down placed, single-crystal silicon substrate using metal-free, ambient-pressure chemical vapor deposition. By controlling the growth temperature, in-plane propagation, edge-propagation, and core-propagation, the process of graphene growth on silicon can be identified. This process produces atomically flat monolayer or bilayer graphene domains, concave bilayer graphene domains, and bulging few-layer graphene domains. This work would be a significant step toward the synthesis of large-area and layer-controlled, high-quality graphene on single-crystal silicon substrates. [Figure not available: see fulltext.

Runaway electron beam control for longitudinally pumped metal vapor lasers

Science.gov (United States)

Kolbychev, G. V.; Kolbycheva, P. D.

1995-08-01

Physics and techniques for producing of the pulsed runaway electron beams are considered. The main obstacle for increasing electron energies in the beams is revealed to be a self- breakdown of the e-gun's gas-filled diode. Two methods to suppress the self-breakdown and enhance the volumetric discharge producing the e-beam are offered and examined. Each of them provides 1.5 fold increase of the ceiling potential on the gun. The methods also give the ways to control several guns simultaneously. Resulting in the possibility of realizing the powerful longitudinal pumping of metal-vapor lasers on self-terminated transitions of atoms or ions.

High mobility single-crystalline-like GaAs thin films on inexpensive flexible metal substrates by metal-organic chemical vapor deposition

International Nuclear Information System (INIS)

Dutta, P.; Rathi, M.; Gao, Y.; Yao, Y.; Selvamanickam, V.; Zheng, N.; Ahrenkiel, P.; Martinez, J.

2014-01-01

We demonstrate heteroepitaxial growth of single-crystalline-like n and p-type doped GaAs thin films on inexpensive, flexible, and light-weight metal foils by metal-organic chemical vapor deposition. Single-crystalline-like Ge thin film on biaxially textured templates made by ion beam assisted deposition on metal foil served as the epitaxy enabling substrate for GaAs growth. The GaAs films exhibited strong (004) preferred orientation, sharp in-plane texture, low grain misorientation, strong photoluminescence, and a defect density of ∼10 7  cm −2 . Furthermore, the GaAs films exhibited hole and electron mobilities as high as 66 and 300 cm 2 /V-s, respectively. High mobility single-crystalline-like GaAs thin films on inexpensive metal substrates can pave the path for roll-to-roll manufacturing of flexible III-V solar cells for the mainstream photovoltaics market.

High mobility single-crystalline-like GaAs thin films on inexpensive flexible metal substrates by metal-organic chemical vapor deposition

Energy Technology Data Exchange (ETDEWEB)

Dutta, P., E-mail: pdutta2@central.uh.edu; Rathi, M.; Gao, Y.; Yao, Y.; Selvamanickam, V. [Department of Mechanical Engineering, University of Houston, Houston, Texas 77204 (United States); Zheng, N.; Ahrenkiel, P. [Department of Nanoscience and Nanoengineering, South Dakota School of Mines and Technology, Rapid City, South Dakota 57701 (United States); Martinez, J. [Materials Evaluation Laboratory, NASA Johnson Space Center, Houston, Texas 77085 (United States)

2014-09-01

We demonstrate heteroepitaxial growth of single-crystalline-like n and p-type doped GaAs thin films on inexpensive, flexible, and light-weight metal foils by metal-organic chemical vapor deposition. Single-crystalline-like Ge thin film on biaxially textured templates made by ion beam assisted deposition on metal foil served as the epitaxy enabling substrate for GaAs growth. The GaAs films exhibited strong (004) preferred orientation, sharp in-plane texture, low grain misorientation, strong photoluminescence, and a defect density of ∼10{sup 7 }cm{sup −2}. Furthermore, the GaAs films exhibited hole and electron mobilities as high as 66 and 300 cm{sup 2}/V-s, respectively. High mobility single-crystalline-like GaAs thin films on inexpensive metal substrates can pave the path for roll-to-roll manufacturing of flexible III-V solar cells for the mainstream photovoltaics market.

Method for producing metallic nanoparticles

Science.gov (United States)

Phillips, Jonathan; Perry, William L.; Kroenke, William J.

2004-02-10

Method for producing metallic nanoparticles. The method includes generating an aerosol of solid metallic microparticles, generating non-oxidizing plasma with a plasma hot zone at a temperature sufficiently high to vaporize the microparticles into metal vapor, and directing the aerosol into the hot zone of the plasma. The microparticles vaporize in the hot zone to metal vapor. The metal vapor is directed away from the hot zone and to the plasma afterglow where it cools and condenses to form solid metallic nanoparticles.

Genetic toxicology of metal compounds: I. Induction of lambda prophage in E coli WP2/sub s/(lambda)

Energy Technology Data Exchange (ETDEWEB)

Rossman, T.G.; Molina, M.; Meyer, L.W.

1984-01-01

A number of metal compounds have been shown to be human carcinogens. Others, while not proven human carcinogens, are able to cause tumors in laboratory animals. Short-term bacterial assays for genotoxic effects have not been successful in predicting the carcinogenicity of metal compounds. The ability of some metal compounds to cause the induction of lambda prophage in E coli WP2/sub s/(lambda) is reported. By far the strongest inducing ability was observed with K/sub 2/CrO/sub 4/. With the exception of chromate, long-term exposures in a narrow, subtoxic dose range were required in order to demonstrate phage induction. A new microtiter assay for lambda prophage induction, which incorporates these features, is described. This system also was able to detect very small amounts of organic carcinogens.

Toward high value sensing: monolayer-protected metal nanoparticles in multivariable gas and vapor sensors.

Science.gov (United States)

Potyrailo, Radislav A

2017-08-29

For detection of gases and vapors in complex backgrounds, "classic" analytical instruments are an unavoidable alternative to existing sensors. Recently a new generation of sensors, known as multivariable sensors, emerged with a fundamentally different perspective for sensing to eliminate limitations of existing sensors. In multivariable sensors, a sensing material is designed to have diverse responses to different gases and vapors and is coupled to a multivariable transducer that provides independent outputs to recognize these diverse responses. Data analytics tools provide rejection of interferences and multi-analyte quantitation. This review critically analyses advances of multivariable sensors based on ligand-functionalized metal nanoparticles also known as monolayer-protected nanoparticles (MPNs). These MPN sensing materials distinctively stand out from other sensing materials for multivariable sensors due to their diversity of gas- and vapor-response mechanisms as provided by organic and biological ligands, applicability of these sensing materials for broad classes of gas-phase compounds such as condensable vapors and non-condensable gases, and for several principles of signal transduction in multivariable sensors that result in non-resonant and resonant electrical sensors as well as material- and structure-based photonic sensors. Such features should allow MPN multivariable sensors to be an attractive high value addition to existing analytical instrumentation.

Experimental study on vapor explosion induced by pressure pulse in coarse mixing of hot molten metal and water

International Nuclear Information System (INIS)

Inoue, A.; Tobita, Y.; Aritomi, M.; Takahashi, M.; Matsuzaki, M.

2004-01-01

An experimental study was done to investigate characteristics of metal-water interaction, when a mount of hot liquid metal is injected into the water. The test section is a vertical shock tube of 60mm in inner diameter and 1200mm in length. A special injector which is designed to inject hot metal of controlled volume and flow rate is attached at the top of the tube. When the hot metal is injected in the water and comes down at a position of the test vessel, a trigger pressure pulse is generated at the bottom of the test tube. Local transient pressures along the tube are measured by piezo pressure transducers. The following items were investigated in the experiment; 1) The criteria to cause a vapor explosion, 2) Transient behaviors and propagation characteristics of pressure wave in the mixing region. 3) Effects of triggering pulse, injection temperature and mass of hot molten metal on the peak pressure. The probability of the vapor explosion jumped when the interface temperature at the molten metal-water direct contact is higher than the homogeneous nucleation temperature of water and the triggering pulse becomes larger than 0.9MPa. Two types of the pressure propagation modes are observed, one is the detonative mode with a sharp rise and other is usual pressure mode with a mild rise. (author)

An evaluation of absorption spectroscopy to monitor YBa2Cu3O7-x precursors for metal organics chemical vapor deposition processing

International Nuclear Information System (INIS)

Matthew Edward Thomas

1999-01-01

Absorption spectroscopy was evaluated as a technique to monitor the metal organics chemical vapor deposition (MOCVD) process for forming YBa 2 Cu 3 O 7-x superconducting coated conductors. Specifically, this study analyzed the feasibility of using absorption spectroscopy to monitor the MOCVD supply vapor concentrations of the organic ligand 2,2,6,6-tetramethyl-3,5-heptanedionate (TMHD) metal chelates of barium, copper, and yttrium. Ba(TMHD) 2 , Cu(TMHD) 2 , and Y(TMHD) 3 compounds have successfully been vaporized in the MOCVD processing technique to form high temperature superconducting ''coated conductors,'' a promising technology for wire fabrication. The absorption study of the barium, copper, and yttrium (TMHD) precursors was conducted in the ultraviolet wavelength region from 200nm to 400nm. To simulate the MOCVD precursor flows the Ba(TMHD) 2 , Cu(TMHD) 2 , and Y(TMHD) 3 complexes were vaporized at vacuum pressures of (0.03--10)Torr. Spectral absorption scans of each precursor were conducted to examine potential measurement wavelengths for determining vapor concentrations of each precursor via Beer's law. The experimental results show that under vacuum conditions the barium, copper, and yttrium (TMHD) precursors begin to vaporize between 90 C and 135 C, which are considerably lower vaporization temperatures than atmospheric thermal gravimetric analyses indicate. Additionally, complete vaporization of the copper and yttrium (TMHD) precursors occurred during rapid heating at temperatures between 145 C and 195 C and after heating at constant temperatures between 90 C and 125 C for approximately one hour, whereas the Ba(TMHD) 2 precursor did not completely vaporize. At constant temperatures, near constant vaporization levels for each precursor were observed for extended periods of time. Detailed spectroscopic scans at stable vaporization conditions were conducted

ANALYSIS OF NONMAGNETIC METAL INDUCTION HEATING PROCESSES BY FLAT-TYPE CIRCULAR SOLENOIDAL FIELD

Directory of Open Access Journals (Sweden)

Yu. Batygin

2016-12-01

Full Text Available The article analyzes the electromagnetic processes in the system of induction heating with estimating the main characteristics of heating the non-magnetic sheet metal. The analytical expressions for numerical estimates of the induced current in terms of the phase of the excitation signal are presented. The dependence for the heating temperature of the considered circular sheet metal area for the time corresponding to the interval phase has been determined.

Cd(1-x)Zn(x)O [0.05 ≤x≤ 0.26] synthesized by vapor-diffusion induced hydrolysis and co-nucleation from aqueous metal salt solutions.

Science.gov (United States)

Schwenzer, Birgit; Neilson, James R; Jeffries, Stacie M; Morse, Daniel E

2011-02-14

Nanoparticulate Cd(1-x)Zn(x)O (x = 0, 0.05-0.26, 1) is synthesized in a simple two-step synthesis approach. Vapor-diffusion induced catalytic hydrolysis of two molecular precursors at low temperature induces co-nucleation and polycondensation to produce bimetallic layered hydroxide salts (M = Cd, Zn) as precursor materials which are subsequently converted to Cd(1-x)Zn(x)O at 400 °C. Unlike ternary materials prepared by standard co-precipitation procedures, all products presented here containing < 30 mol% Zn(2+) ions are homogeneous in elemental composition on the micrometre scale. This measured compositional homogeneity within the samples, as determined by energy dispersive spectroscopy and inductively coupled plasma spectroscopy, is a testimony to the kinetic control achieved by employing slow hydrolysis conditions. In agreement with this observation, the optical properties of the materials obey Vegard's Law for a homogeneous solid solution of Cd(1-x)Zn(x)O, where x corresponds to the values determined by inductively coupled plasma analysis, even though powder X-ray diffraction shows phase separation into a cubic mixed metal oxide phase and a hexagonal ZnO phase at all doping levels.

D- production by multiple charge-transfer collisions in metal-vapor targets. [1 to 50 keV D/sup +/

Energy Technology Data Exchange (ETDEWEB)

Schlachter, A.S.

1977-09-01

A beam of D/sup -/ions can be produced by multiple charge-transfer collisions of a D/sup +/ beam in a thick metal-vapor target. Cross sections and equilibrium charge-state fractions are presented and discussed.

TVA - Thermionic Vacuum Arc - A new type of discharge generating pure metal vapor plasma

International Nuclear Information System (INIS)

Musa, G.; Popescu, A.; Mustata, I.; Borcoman, I.; Cretu, M.; Leu, G.F.; Salambas, A.; Ehrich, H.; Schumann, I.

1996-01-01

In this paper it is presented a new type of discharge in vacuum conditions generating pure metal vapor plasma with energetic metal ions content. The peculiarities of this heated cathode discharge are described and the dependence of the measured ion energy of the working parameters are established. The ion energy value can be easily and smoothly changed. A nearly linear dependence between energy of ions and arc voltage drop has been observed. The ion energy can be increased by the increase of the interelectrode distance, decrease of cathode temperature, change of the relative position of the electrodes and by the decrease of the arc discharge current. A special configuration with cylindrical geometry has been used to develop a small size and compact metal vapour plasma gun. Due to the mentioned peculiarities, this discharge offers new openings for important applications. (author)

Suitable alkaline for graphene peeling grown on metallic catalysts using chemical vapor deposition

Energy Technology Data Exchange (ETDEWEB)

Karamat, S., E-mail: shumailakaramat@gmail.com [Department of Physics, Middle East Technical University, Ankara 06800 (Turkey); COMSATS Institute of Information Technology, Islamabad 54000 (Pakistan); Sonuşen, S. [Sabancı Üniversitesi (SUNUM), İstanbul 34956 (Turkey); Çelik, Ü. [Nanomagnetics Instruments, Ankara (Turkey); Uysallı, Y. [Department of Physics, Middle East Technical University, Ankara 06800 (Turkey); Oral, A., E-mail: orahmet@metu.edu.tr [Department of Physics, Middle East Technical University, Ankara 06800 (Turkey)

2016-04-15

Graphical abstract: - Highlights: • Graphene layers were grown on Pt and Cu foil via ambient pressure chemical vapor deposition method and for the delicate removal of graphene from metal catalysts, electrolysis method was used by using different alkaline (sodium hydroxide, potassium hydroxide, lithium hydroxide and barium hydroxide). • The delamination speed of PMMA/graphene stack was higher during the KOH and LiOH electrolysis as compare to NaOH and Ba(OH){sub 2}. Ba(OH){sub 2} is not advisable because of the residues left on the graphene surface which would further trapped in between graphene and SiO{sub 2}/Si surface after transfer. The average peeling time in case of Pt electrode is ∼6 min for KOH and LiOH and ∼15 min for NaOH and Ba(OH){sub 2}. • Electrolysis method also works for the Cu catalyst. The peeling of graphene was faster in the case of Cu foil due to small size of bubbles which moves faster between the stack and the electrode surface. The average peeling time was ∼3–5 min. • XPS analysis clearly showed that the Pt substrates can be re-used again. Graphene layer was transferred to SiO{sub 2}/Si substrates and to the flexible substrate by using the same peeling method. - Abstract: In chemical vapor deposition, the higher growth temperature roughens the surface of the metal catalyst and a delicate method is necessary for the transfer of graphene from metal catalyst to the desired substrates. In this work, we grow graphene on Pt and Cu foil via ambient pressure chemical vapor deposition (AP-CVD) method and further alkaline water electrolysis was used to peel off graphene from the metallic catalyst. We used different electrolytes i.e., sodium hydroxide (NaOH), potassium hydroxide (KOH), lithium hydroxide (LiOH) and barium hydroxide Ba(OH){sub 2} for electrolysis, hydrogen bubbles evolved at the Pt cathode (graphene/Pt/PMMA stack) and as a result graphene layer peeled off from the substrate without damage. The peeling time for KOH and Li

Suitable alkaline for graphene peeling grown on metallic catalysts using chemical vapor deposition

International Nuclear Information System (INIS)

Karamat, S.; Sonuşen, S.; Çelik, Ü.; Uysallı, Y.; Oral, A.

2016-01-01

Graphical abstract: - Highlights: • Graphene layers were grown on Pt and Cu foil via ambient pressure chemical vapor deposition method and for the delicate removal of graphene from metal catalysts, electrolysis method was used by using different alkaline (sodium hydroxide, potassium hydroxide, lithium hydroxide and barium hydroxide). • The delamination speed of PMMA/graphene stack was higher during the KOH and LiOH electrolysis as compare to NaOH and Ba(OH)_2. Ba(OH)_2 is not advisable because of the residues left on the graphene surface which would further trapped in between graphene and SiO_2/Si surface after transfer. The average peeling time in case of Pt electrode is ∼6 min for KOH and LiOH and ∼15 min for NaOH and Ba(OH)_2. • Electrolysis method also works for the Cu catalyst. The peeling of graphene was faster in the case of Cu foil due to small size of bubbles which moves faster between the stack and the electrode surface. The average peeling time was ∼3–5 min. • XPS analysis clearly showed that the Pt substrates can be re-used again. Graphene layer was transferred to SiO_2/Si substrates and to the flexible substrate by using the same peeling method. - Abstract: In chemical vapor deposition, the higher growth temperature roughens the surface of the metal catalyst and a delicate method is necessary for the transfer of graphene from metal catalyst to the desired substrates. In this work, we grow graphene on Pt and Cu foil via ambient pressure chemical vapor deposition (AP-CVD) method and further alkaline water electrolysis was used to peel off graphene from the metallic catalyst. We used different electrolytes i.e., sodium hydroxide (NaOH), potassium hydroxide (KOH), lithium hydroxide (LiOH) and barium hydroxide Ba(OH)_2 for electrolysis, hydrogen bubbles evolved at the Pt cathode (graphene/Pt/PMMA stack) and as a result graphene layer peeled off from the substrate without damage. The peeling time for KOH and LiOH was ∼6 min and for NaOH and

(abstract) Experimental and Modeling Studies of the Exchange Current at the Alkali Beta'-Alumina/Porous Electrode/Alkali Metal Vapor Three Phase Boundary

Science.gov (United States)

Williams, R. M.; Jeffries-Nakamura, B.; Ryan, M. A.; Underwood, M. L.; O'Connor, D.; Kikkert, S.

1993-01-01

The microscopic mechanism of the alkali ion-electron recombination reaction at the three phase boundary zone formed by a porous metal electrode in the alkali vapor on the surface of an alkali beta'-alumina solid electrolyte (BASE) ceramic has been studied by comparison of the expected rates for the three simplest reaction mechanisms with known temperature dependent rate data; and the physical parameters of typical porous metal electrode/BASE/alkali metal vapor reaction zones. The three simplest reactions are tunneling of electrons from the alkali coated electrode to a surface bound alkali metal ion; emission of an electron from the electrode with subsequent capture by a surface bound alkali metal ion; and thermal emission of an alkali cation from the BASE and its capture on the porous metal electrode surface where it may recombine with an electron. Only the first reaction adequately accounts for both the high observed rate and its temperature dependence. New results include crude modeling of simple, one step, three phase, solid/solid/gas electrochemical reaction.

Genetic toxicology of metal compounds. I. Induction of lambda prophage in E coli WP2/sub s/(lambda)

Energy Technology Data Exchange (ETDEWEB)

Rossman, T.G.; Molina, M.; Meyer, L.W.

1984-01-01

A number of metal compounds have been shown to be human carcinogens. Others, while not proven human carcinogens, are able to cause tumors in laboratory animals. Short-term bacterial assays for genotoxic effects have not been successful in predicting the carcinogenicity of metal compounds. The authors report here the ability of some metal compounds to cause the induction of lambda prophage in E coli WP2/sub s/(lambda). By far the strongest inducing ability was observed with K/sub 2/CrO/sub 4/, followed by Pb(NO/sub 3/)/sub 2/ > Ni(OOCCH/sub 3/)/sub 2/ > CrCl/sub 2/ > NaWO/sub 4/ > Na/sub 2/MoO/sub 4/ > KMnO/sub 4/. With the exception of chromate, long-term exposures in a narrow, subtoxic dose range were required in order to demonstrate phage induction. A new microtiter assay for lambda prophage induction, which incorporates these features, is described. This system also was able to detect very small amounts of organic carcinogens.

Vapor phase carbonylation of dimethyl ether and methyl acetate with supported transition metal catalysts

International Nuclear Information System (INIS)

Shikada, T.; Fujimoto, K.; Tominaga, H.O.

1986-01-01

The synthesis of acetic acid (AcOH) from methanol (MeOH) and carbon monoxide has been performed industrially in the liquid phase using a rhodium complex catalyst and an iodide promoter. The selectivity to AcOH is more than 99% under mild conditions (175 0 C, 28 atm). The homogeneous rhodium catalyst has been also effective for the synthesis of acetic anhydride (Ac 2 O) by carbonylation of dimethyl ether (DME) or methyl acetate (AcOMe). However, rhodium is one of the most expensive metals and its proved reserves are quite limited. It is highly desired, therefore, to develop a new catalyst as a substitute for rhodium. The authors have already reported that nickel supported on active carbon exhibits an excellent activity for the vapor phase carbonylation of MeOh in the presence of iodide promoter and under moderately pressurized conditions. In addition, corrosive attack on reactors by iodide compounds is expected to be negligible in the vapor phase system. In the present work, vapor phase carbonylation of DME and AcOMe on nickel-active carbon (Ni/A.C.) and molybdenum-active carbon (Mo/A.C.) catalysts was studied

Structured nanocarbon on various metal foils by microwave plasma enhanced chemical vapor deposition

International Nuclear Information System (INIS)

Rius, G; Yoshimura, M

2013-01-01

We present a versatile process for the engineering of nanostructures made of crystalline carbon on metal foils. The single step process by microwave plasma-enhance chemical vapor deposition is demonstrated for various substrate materials, such as Ni or Cu. Either carbon nanotubes (CNT) or carbon nanowalls (CNW) are obtained under same growth conditions and without the need of additional catalyst. The use of spacer and insulator implies a certain control over the kind of allotropes that are obtained. High density and large surface area are morphological characteristics of the thus obtained C products. The possibility of application on many metals, and in the alloy composition, on as-delivered commercially available foils indicates that this strategy can be adapted to a bunch of specific applications, while the production of C nanostructures is of remarkable simplicity.

Problems of hydrogen - water vapor - inert gas mixture use in heavy liquid metal coolant technology

International Nuclear Information System (INIS)

Ul'yanov, V.V.; Martynov, P.N.; Gulevskij, V.A.; Teplyakov, Yu.A.; Fomin, A.S.

2014-01-01

The reasons of slag deposit formation in circulation circuits with heavy liquid metal coolants, which can cause reactor core blockage, are considered. To prevent formation of deposits hydrogen purification of coolant and surfaces of circulation circuit is used. It consists in introduction of gaseous mixtures hydrogen - water vapor - rare gas (argon or helium) directly into coolant flow. The principle scheme of hydrogen purification and the processes occurring during it are under consideration. Measures which make it completely impossible to overlap of the flow cross section of reactor core, steam generators, pumps and other equipment by lead oxides in reactor facilities with heavy liquid metal coolants are listed [ru

Toxicological responses of environmental mixtures: Environmental metal mixtures display synergistic induction of metal-responsive and oxidative stress genes in placental cells

Energy Technology Data Exchange (ETDEWEB)

Adebambo, Oluwadamilare A. [Department of Biological Sciences, North Carolina State University (United States); Ray, Paul D. [Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill (United States); Shea, Damian [Department of Biological Sciences, North Carolina State University (United States); Fry, Rebecca C., E-mail: rfry@unc.edu [Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill (United States)

2015-12-15

Exposure to elevated levels of the toxic metals inorganic arsenic (iAs) and cadmium (Cd) represents a major global health problem. These metals often occur as mixtures in the environment, creating the potential for interactive or synergistic biological effects different from those observed in single exposure conditions. In the present study, environmental mixtures collected from two waste sites in China and comparable mixtures prepared in the laboratory were tested for toxicogenomic response in placental JEG-3 cells. These cells serve as a model for evaluating cellular responses to exposures during pregnancy. One of the mixtures was predominated by iAs and one by Cd. Six gene biomarkers were measured in order to evaluate the effects from the metal mixtures using dose and time-course experiments including: heme oxygenase 1 (HO-1) and metallothionein isoforms (MT1A, MT1F and MT1G) previously shown to be preferentially induced by exposure to either iAs or Cd, and metal transporter genes aquaporin-9 (AQP9) and ATPase, Cu{sup 2+} transporting, beta polypeptide (ATP7B). There was a significant increase in the mRNA expression levels of ATP7B, HO-1, MT1A, MT1F, and MT1G in mixture-treated cells compared to the iAs or Cd only-treated cells. Notably, the genomic responses were observed at concentrations significantly lower than levels found at the environmental collection sites. These data demonstrate that metal mixtures increase the expression of gene biomarkers in placental JEG-3 cells in a synergistic manner. Taken together, the data suggest that toxic metals that co-occur may induce detrimental health effects that are currently underestimated when analyzed as single metals. - Highlights: • Toxicogenomic responses of environmental metal mixtures assessed • Induction of ATP7B, HO-1, MT1A, MT1F and MT1G by metal mixtures observed in placental cells • Higher gene induction in response to metal mixtures versus single metal treatments.

Toxicological responses of environmental mixtures: Environmental metal mixtures display synergistic induction of metal-responsive and oxidative stress genes in placental cells

International Nuclear Information System (INIS)

Adebambo, Oluwadamilare A.; Ray, Paul D.; Shea, Damian; Fry, Rebecca C.

2015-01-01

Exposure to elevated levels of the toxic metals inorganic arsenic (iAs) and cadmium (Cd) represents a major global health problem. These metals often occur as mixtures in the environment, creating the potential for interactive or synergistic biological effects different from those observed in single exposure conditions. In the present study, environmental mixtures collected from two waste sites in China and comparable mixtures prepared in the laboratory were tested for toxicogenomic response in placental JEG-3 cells. These cells serve as a model for evaluating cellular responses to exposures during pregnancy. One of the mixtures was predominated by iAs and one by Cd. Six gene biomarkers were measured in order to evaluate the effects from the metal mixtures using dose and time-course experiments including: heme oxygenase 1 (HO-1) and metallothionein isoforms (MT1A, MT1F and MT1G) previously shown to be preferentially induced by exposure to either iAs or Cd, and metal transporter genes aquaporin-9 (AQP9) and ATPase, Cu 2+ transporting, beta polypeptide (ATP7B). There was a significant increase in the mRNA expression levels of ATP7B, HO-1, MT1A, MT1F, and MT1G in mixture-treated cells compared to the iAs or Cd only-treated cells. Notably, the genomic responses were observed at concentrations significantly lower than levels found at the environmental collection sites. These data demonstrate that metal mixtures increase the expression of gene biomarkers in placental JEG-3 cells in a synergistic manner. Taken together, the data suggest that toxic metals that co-occur may induce detrimental health effects that are currently underestimated when analyzed as single metals. - Highlights: • Toxicogenomic responses of environmental metal mixtures assessed • Induction of ATP7B, HO-1, MT1A, MT1F and MT1G by metal mixtures observed in placental cells • Higher gene induction in response to metal mixtures versus single metal treatments

Induction skull melting facility: an advanced system for electromagnetic processing of metals and alloys

International Nuclear Information System (INIS)

Sugilal, G.; Agarwal, K.

2017-01-01

Induction Skull Melting (ISM) is an advanced technology for processing highly refractory and extremely reactive metals and their alloys to produce ultra-high purity products. In ISM, the metallic charge is melted in a water-cooled, copper crucible. The crucible is segmented so that the magnetic field can penetrate into the metallic charge to be melted. By virtue of the strong electromagnetic stirring, the ISM technology can also be used to homogenize alloys of metals, which are difficult to be combined uniformly in composition due to large difference in specific gravity. In view of various important applications in frontier areas of material research, development and production, Bhabha Atomic Research Centre developed the ISM technology indigenously

Direct determination of trace rare earth elements in ancient porcelain samples with slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry

International Nuclear Information System (INIS)

Xiang Guoqiang; Jiang Zucheng; He Man; Hu Bin

2005-01-01

A method for the direct determination of trace rare earth elements in ancient porcelain samples by slurry sampling fluorinating electrothermal vaporization inductively coupled plasma mass spectrometry was developed with the use of polytetrafluoroethylene as fluorinating reagent. It was found that Si, as a main matrix element in ancient porcelain sample, could be mostly removed at the ashing temperature of 1200 deg. C without considerable losses of the analytes. However, the chemical composition of ancient porcelain sample is very complicated, which makes the influences resulting from other matrix elements not be ignored. Therefore, the matrix effect of ancient porcelain sample was also investigated, and it was found that the matrix effect is obvious when the matrix concentration was larger than 0.8 g l -1 . The study results of particle size effect indicated that when the sample particle size was less than 0.057 mm, the particle size effect is negligible. Under the optimized operation conditions, the detection limits for rare earth elements by fluorinating electrothermal vaporization inductively coupled plasma mass spectrometry were 0.7 ng g -1 (Eu)-33.3 ng g -1 (Nd) with the precisions of 4.1% (Yb)-10% (La) (c = 1 μg l -1 , n = 9). The proposed method was used to directly determine the trace rare earth elements in ancient porcelain samples produced in different dynasty (Sui, Ming and Qing), and the analytical results are satisfactory

The evaluation of different environments in ultra-high frequency induction sintered powder metal compacts

International Nuclear Information System (INIS)

Cavdar, P. S.; Cavdar, U.

2015-01-01

The application of the iron based Powder Metal (PM) compacts in Ultra-High Frequency Induction Sintering (UHFIS) was reviewed for different environments. The three different environments: atmosphere, argon and vacuum were applied to the PM compacts. Iron based PM compacts were sintered at 1120 degree centigrade for a total of 550 seconds by using induction sintering machines with 2.8 kW power and 900 kHz frequency. Micro structural properties, densities, roughness and micro hardness values were obtained for all environments. The results were compared with each other. (Author)

Magnetron target designs to improve wafer edge trench filling in ionized metal physical vapor deposition

International Nuclear Information System (INIS)

Lu Junqing; Yoon, Jae-Hong; Shin, Keesam; Park, Bong-Gyu; Yang Lin

2006-01-01

Severe asymmetry of the metal deposits on the trench sidewalls occurs near the wafer edge during low pressure ionized metal physical vapor deposition of Cu seed layer for microprocessor interconnects. To investigate this process and mitigate the asymmetry, an analytical view factor model based on the analogy between metal sputtering and diffuse thermal radiation was constructed. The model was validated based on the agreement between the model predictions and the reported experimental values for the asymmetric metal deposition at trench sidewalls near the wafer edge for a 200 mm wafer. This model could predict the thickness of the metal deposits across the wafer, the symmetry of the deposits on the trench sidewalls at any wafer location, and the angular distributions of the metal fluxes arriving at any wafer location. The model predictions for the 300 mm wafer indicate that as the target-to-wafer distance is shortened, the deposit thickness increases and the asymmetry decreases, however the overall uniformity decreases. Up to reasonable limits, increasing the target size and the sputtering intensity for the outer target portion significantly improves the uniformity across the wafer and the symmetry on the trench sidewalls near the wafer edge

Immunoelectron microscopic studies on metallothionein induction in Nile cichlid due to heavy metal stress

International Nuclear Information System (INIS)

Chatterjee, S.; Singh, L.; Das, T.K.; Mukhopadhyay, S.K.

2010-01-01

Heavy metals are important environmental pollutants and many of them are toxic even in low concentrations. The uncontrolled input of such elements in milieu is undesirable because once accumulated, are hard to remove. The release of toxic metals in biologically available forms by human activity may damage or alter both natural and man-made ecosystems. The cellular adaptation to toxicity of metals is one of the important factors for organisms living in the stressful conditions. The major type of cellular effect at the cytoplasmic level involves binding of metals through specific metal binding proteins. One of these metalloproteins is metallothionein (MT), MT is a low-molecular-weight (6-7 kDa) cysteine rich protein ubiquitous in the animal kingdom and can bind with essential (Cu + and Zn 2+ ) and nonessential (Cd 2+ , Hg 2+ and Ag + ) metals with a high thermodynamic and low kinetic stability. Again, the induction of MT by other heavy metals such as Cr, Mn and Pb was also reported by several workers

Reduced water vapor transmission rates of low-temperature solution-processed metal oxide barrier films via ultraviolet annealing

Energy Technology Data Exchange (ETDEWEB)

Park, Seonuk; Jeong, Yong Jin; Baek, Yonghwa; Kim, Lae Ho; Jang, Jin Hyuk; Kim, Yebyeol [POSTECH Organic Electronics Laboratory, Polymer Research Institute, Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, 790-784 (Korea, Republic of); An, Tae Kyu [Department of Polymer Science & Engineering, Korea National University of Transportation, 50 Daehak-Ro, Chungju (Korea, Republic of); Nam, Sooji, E-mail: sjnam15@etri.re.kr [Information Control Device Section, Electronics and Telecommunications Research Institute, Daejeon, 305-700 (Korea, Republic of); Kim, Se Hyun, E-mail: shkim97@yu.ac.kr [School of Chemical Engineering, Yeungnam University, Gyeongsan, North Gyeongsang 712-749 (Korea, Republic of); Jang, Jaeyoung, E-mail: jyjang15@hanyang.ac.kr [Department of Energy Engineering, Hanyang University, Seoul, 133-791 (Korea, Republic of); Park, Chan Eon, E-mail: cep@postech.ac.kr [POSTECH Organic Electronics Laboratory, Polymer Research Institute, Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, 790-784 (Korea, Republic of)

2017-08-31

Highlights: • Sol-gel-derived aluminum oxide thin films were prepared using ultraviolet (UV) annealing. • UV irradiation dramatically promoted the densification of AlO{sub x} during the annealing stage, thereby forming a close-packed AlO{sub x} film. • The resulting AlO{sub x} films deposited on polymer substrates exhibited good water vapor blocking properties with low water vapor transmission rates (WVTRs). - Abstract: Here, we report the fabrication of low-temperature sol-gel-derived aluminum oxide (AlO{sub x}) films via ultraviolet (UV) annealing and the investigation of their water vapor blocking properties by measuring the water vapor transmission rates (WVTRs). The UV annealing process induced the formation of a dense metal-oxygen-metal bond (Al-O-Al structure) at low temperatures (<200 °C) that are compatible with commercial plastic substrates. The density of the UV-annealed AlO{sub x} thin film at 180 °C was comparable to that of AlO{sub x} thin films that have been thermally annealed at 350 °C. Furthermore, the UV-annealed AlO{sub x} thin films exhibited a high optical transparency in the visible region (>99%) and good electrical insulating properties (∼10{sup −7} A/cm{sup 2} at 2 MV/cm). Finally, we confirmed that a dense AlO{sub x} thin film was successfully deposited onto the plastic substrate via UV annealing at low temperatures, leading to a substantial reduction in the WVTRs. The Ca corrosion test was used to measure the WVTRs of AlO{sub x} thin films deposited onto polyethylene naphthalate or polyimide substrates, determined to be 0.0095 g m{sup −2} day{sup −1} (25 °C, 50% relative humidity) and 0.26 g m{sup −2} day{sup −1}, respectively.

INDUCTION HEATING OF NON-MAGNETIC SHEET METALS IN THE FIELD OF A FLAT CIRCULAR MULTITURN SOLENOID

Directory of Open Access Journals (Sweden)

Y. Batygin

2016-06-01

Full Text Available The theoretical analysis of electromagnetic processes in the system for induction heating presented by a flat circular multiturn solenoid positioned above a plane of thin sheet non-magnetic metal has been conducted. The calculated dependences for the current induced in a metal sheet blank and ratio of transformation determined have been obtained. The maximal value of the transformation ratio with regard to spreading the eddy-currents over the whole area of the sheet metal has been determined.

Non-catalytic direct synthesis of graphene on Si (111) wafers by using inductively-coupled plasma chemical vapor deposition

Science.gov (United States)

Hwang, Sung Won; Shin, Hyunho; Lee, Bongsoo; Choi, Suk-Ho

2016-08-01

We employ inductively-coupled plasma chemical vapor deposition for non-catalytic growth of graphene on a Si (111) wafer or glass substrate, which is useful for practical device applications of graphene without transfer processes. At a RF power (P) of 500 W under C2H2 flow, defect-free 3 ˜ 5-layer graphene is grown on Si (111) wafers, but on glass substrate, the layer is thicker and defective, as characterized by Raman spectroscopy and electron microscopy. The graphene is produced on Si (111) for P down to 190 W whereas it is almost not formed on glass for P < 250 W, possibly resulting from the weak catalytic-reaction-like effect on glass. These results are discussed based on possible growth mechanisms.

Coupling scales for modelling heavy metal vaporization from municipal solid waste incineration in a fluid bed by CFD

Energy Technology Data Exchange (ETDEWEB)

Soria, José, E-mail: jose.soria@probien.gob.ar [Institute for Research and Development in Process Engineering, Biotechnology and Alternative Energies (PROBIEN, CONICET – UNCo), 1400 Buenos Aires St., 8300 Neuquén (Argentina); Gauthier, Daniel; Flamant, Gilles [Processes, Materials and Solar Energy Laboratory (PROMES-CNRS, UPR 8521), 7 Four Solaire Street, Odeillo, 66120 Font-Romeu (France); Rodriguez, Rosa [Chemical Engineering Institute, National University of San Juan, 1109 Libertador (O) Avenue, 5400 San Juan (Argentina); Mazza, Germán [Institute for Research and Development in Process Engineering, Biotechnology and Alternative Energies (PROBIEN, CONICET – UNCo), 1400 Buenos Aires St., 8300 Neuquén (Argentina)

2015-09-15

Highlights: • A CFD two-scale model is formulated to simulate heavy metal vaporization from waste incineration in fluidized beds. • MSW particle is modelled with the macroscopic particle model. • Influence of bed dynamics on HM vaporization is included. • CFD predicted results agree well with experimental data reported in literature. • This approach may be helpful for fluidized bed reactor modelling purposes. - Abstract: Municipal Solid Waste Incineration (MSWI) in fluidized bed is a very interesting technology mainly due to high combustion efficiency, great flexibility for treating several types of waste fuels and reduction in pollutants emitted with the flue gas. However, there is a great concern with respect to the fate of heavy metals (HM) contained in MSW and their environmental impact. In this study, a coupled two-scale CFD model was developed for MSWI in a bubbling fluidized bed. It presents an original scheme that combines a single particle model and a global fluidized bed model in order to represent the HM vaporization during MSW combustion. Two of the most representative HM (Cd and Pb) with bed temperatures ranging between 923 and 1073 K have been considered. This new approach uses ANSYS FLUENT 14.0 as the modelling platform for the simulations along with a complete set of self-developed user-defined functions (UDFs). The simulation results are compared to the experimental data obtained previously by the research group in a lab-scale fluid bed incinerator. The comparison indicates that the proposed CFD model predicts well the evolution of the HM release for the bed temperatures analyzed. It shows that both bed temperature and bed dynamics have influence on the HM vaporization rate. It can be concluded that CFD is a rigorous tool that provides valuable information about HM vaporization and that the original two-scale simulation scheme adopted allows to better represent the actual particle behavior in a fluid bed incinerator.

Coupling scales for modelling heavy metal vaporization from municipal solid waste incineration in a fluid bed by CFD

International Nuclear Information System (INIS)

Soria, José; Gauthier, Daniel; Flamant, Gilles; Rodriguez, Rosa; Mazza, Germán

2015-01-01

Highlights: • A CFD two-scale model is formulated to simulate heavy metal vaporization from waste incineration in fluidized beds. • MSW particle is modelled with the macroscopic particle model. • Influence of bed dynamics on HM vaporization is included. • CFD predicted results agree well with experimental data reported in literature. • This approach may be helpful for fluidized bed reactor modelling purposes. - Abstract: Municipal Solid Waste Incineration (MSWI) in fluidized bed is a very interesting technology mainly due to high combustion efficiency, great flexibility for treating several types of waste fuels and reduction in pollutants emitted with the flue gas. However, there is a great concern with respect to the fate of heavy metals (HM) contained in MSW and their environmental impact. In this study, a coupled two-scale CFD model was developed for MSWI in a bubbling fluidized bed. It presents an original scheme that combines a single particle model and a global fluidized bed model in order to represent the HM vaporization during MSW combustion. Two of the most representative HM (Cd and Pb) with bed temperatures ranging between 923 and 1073 K have been considered. This new approach uses ANSYS FLUENT 14.0 as the modelling platform for the simulations along with a complete set of self-developed user-defined functions (UDFs). The simulation results are compared to the experimental data obtained previously by the research group in a lab-scale fluid bed incinerator. The comparison indicates that the proposed CFD model predicts well the evolution of the HM release for the bed temperatures analyzed. It shows that both bed temperature and bed dynamics have influence on the HM vaporization rate. It can be concluded that CFD is a rigorous tool that provides valuable information about HM vaporization and that the original two-scale simulation scheme adopted allows to better represent the actual particle behavior in a fluid bed incinerator

A Compact Ionic Polymer Metal Composite (IPMC System with Inductive Sensor for Closed Loop Feedback

Directory of Open Access Journals (Sweden)

Jiaqi Wang

2015-05-01

Full Text Available Ionic polymer metal composite (IPMC, of which a low actuating voltage (<5 V, high power efficiency and biocompatibility makes it a proven candidate for low power devices. However, due to its inherent nonlinear behaviour and time-variance, feedback control, as well as reliable sensing means, are required for accurate operations. This paper presents an IPMC actuator implemented with an inductive sensor to enhance the reliability and compactness of the overall device. A practical, low cost and importantly, compact inductive sensor fabricated on a printed circuit board (PCB is proposed here. Target material selections and coil design considerations are discussed. It is experimentally determined that the inductive sensor has comparable performance to a laser sensor. Based on a proportional-integral-derivative (PID control results the inductive sensor has demonstrated to be an alternative to a laser sensor allowing devices using IPMC actuators to be compact.

Growth kinetics and mass transport mechanisms of GaN columns by selective area metal organic vapor phase epitaxy

Science.gov (United States)

Wang, Xue; Hartmann, Jana; Mandl, Martin; Sadat Mohajerani, Matin; Wehmann, Hergo-H.; Strassburg, Martin; Waag, Andreas

2014-04-01

Three-dimensional GaN columns recently have attracted a lot of attention as the potential basis for core-shell light emitting diodes for future solid state lighting. In this study, the fundamental insights into growth kinetics and mass transport mechanisms of N-polar GaN columns during selective area metal organic vapor phase epitaxy on patterned SiOx/sapphire templates are systematically investigated using various pitch of apertures, growth time, and silane flow. Species impingement fluxes on the top surface of columns Jtop and on their sidewall Jsw, as well as, the diffusion flux from the substrate Jsub contribute to the growth of the GaN columns. The vertical and lateral growth rates devoted by Jtop, Jsw and Jsub are estimated quantitatively. The diffusion length of species on the SiOx mask surface λsub as well as on the sidewall surfaces of the 3D columns λsw are determined. The influences of silane on the growth kinetics are discussed. A growth model is developed for this selective area metal organic vapor phase epitaxy processing.

Collision Welding of Dissimilar Materials by Vaporizing Foil Actuator: A Breakthrough Technology for Dissimilar Metal Joining

Energy Technology Data Exchange (ETDEWEB)

Daehn, Glenn S. [The Ohio State Univ., Columbus, OH (United States). Dept. of Materials Science and Engineering; Vivek, Anupam [The Ohio State Univ., Columbus, OH (United States). Dept. of Materials Science and Engineering; Liu, Bert C. [The Ohio State Univ., Columbus, OH (United States). Dept. of Materials Science and Engineering

2016-09-30

This work demonstrated and further developed Vaporizing Foil Actuator Welding (VFAW) as a viable technique for dissimilar-metal joining for automotive lightweighting applications. VFAW is a novel impact welding technology, which uses the pressure developed from electrically-assisted rapid vaporization of a thin aluminum foil (the consumable) to launch and ultimately collide two of more pieces of metal to create a solid-state bond between them. 18 dissimilar combinations of automotive alloys from the steel, aluminum and magnesium alloy classes were screened for weldability and characterized by metallography of weld cross sections, corrosion testing, and mechanical testing. Most combinations, especially a good number of Al/Fe pairs, were welded successfully. VFAW was even able to weld combinations of very high strength materials such as 5000 and 6000 series aluminum alloys to boron and dual phase steels, which is difficult to impossible by other joining techniques such as resistance spot welding, friction stir welding, or riveting. When mechanically tested, the samples routinely failed in a base metal rather than along the weld interface, showing that the weld was stronger than either of the base metals. As for corrosion performance, a polymer-based protective coating was used to successfully combat galvanic corrosion of 5 Al/Fe pairs through a month-long exposure to warm salt fog. In addition to the technical capabilities, VFAW also consumes little energy compared to conventional welding techniques and requires relatively light, flexible tooling. Given the technical and economic advantages, VFAW can be a very competitive joining technology for automotive lightweighting. The success of this project and related activities has resulted in substantial interest not only within the research community but also various levels of automotive supply chain, which are collaborating to bring this technology to commercial use.

An efficient laser vaporization source for chemically modified metal clusters characterized by thermodynamics and kinetics

Science.gov (United States)

Masubuchi, Tsugunosuke; Eckhard, Jan F.; Lange, Kathrin; Visser, Bradley; Tschurl, Martin; Heiz, Ulrich

2018-02-01

A laser vaporization cluster source that has a room for cluster aggregation and a reactor volume, each equipped with a pulsed valve, is presented for the efficient gas-phase production of chemically modified metal clusters. The performance of the cluster source is evaluated through the production of Ta and Ta oxide cluster cations, TaxOy+ (y ≥ 0). It is demonstrated that the cluster source produces TaxOy+ over a wide mass range, the metal-to-oxygen ratio of which can easily be controlled by changing the pulse duration that influences the amount of reactant O2 introduced into the cluster source. Reaction kinetic modeling shows that the generation of the oxides takes place under thermalized conditions at less than 300 K, whereas metal cluster cores are presumably created with excess heat. These characteristics are also advantageous to yield "reaction intermediates" of interest via reactions between clusters and reactive molecules in the cluster source, which may subsequently be mass selected for their reactivity measurements.

Ultra-trace determination of gold nanoparticles in environmental water by surfactant assisted dispersive liquid liquid microextraction coupled with electrothermal vaporization-inductively coupled plasma-mass spectrometry

Science.gov (United States)

Liu, Ying; He, Man; Chen, Beibei; Hu, Bin

2016-08-01

A new method by coupling surfactant assisted dispersive liquid liquid microextraction (SA-DLLME) with electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) was proposed for the analysis of gold nanoparticles (AuNPs) in environmental water samples. Effective separation of AuNPs from ionic gold species was achieved by using sodium thiosulphate as a complexing agent. Various experimental parameters affecting SA-DLLME of AuNPs, such as the organic solvent, organic solvent volume, pH of the sample, the kind of surfactant, surfactant concentration, vortex time, speed of centrifugation, centrifugation time, and different coating as well as sizes of AuNPs were investigated carefully. Furthermore, the interference of coexisting ions, dissolved organic matter (DOM) and other metal nanoparticles (NPs) were studied. Under the optimal conditions, a detection limit of 2.2 ng L- 1 and an enrichment factor of 152-fold was achieved for AuNPs, and the original morphology of the AuNPs could be maintained during the extraction process. The developed method was successfully applied for the analysis of AuNPs in environmental water samples, including tap water, the East Lake water, and the Yangtze River water, with recoveries in the range of 89.6-102%. Compared with the established methods for metal NPs analysis, the proposed method has the merits of simple and fast operation, low detection limit, high selectivity, good tolerance to the sample matrix and no digestion or dilution required. It provides an efficient quantification methodology for monitoring AuNPs' pollution in the environmental water and evaluating its toxicity.

Vapor deposition of tantalum and tantalum compounds

International Nuclear Information System (INIS)

Trkula, M.

1996-01-01

Tantalum, and many of its compounds, can be deposited as coatings with techniques ranging from pure, thermal chemical vapor deposition to pure physical vapor deposition. This review concentrates on chemical vapor deposition techniques. The paper takes a historical approach. The authors review classical, metal halide-based techniques and current techniques for tantalum chemical vapor deposition. The advantages and limitations of the techniques will be compared. The need for new lower temperature processes and hence new precursor chemicals will be examined and explained. In the last section, they add some speculation as to possible new, low-temperature precursors for tantalum chemical vapor deposition

Comparison of single-use and reusable metal laryngoscope blades for orotracheal intubation during rapid sequence induction of anesthesia: a multicenter cluster randomized study.

Science.gov (United States)

Amour, Julien; Le Manach, Yannick Le; Borel, Marie; Lenfant, François; Nicolas-Robin, Armelle; Carillion, Aude; Ripart, Jacques; Riou, Bruno; Langeron, Olivier

2010-02-01

Single-use metal laryngoscope blades are cheaper and carry a lower risk of infection than reusable metal blades. The authors compared single-use and reusable metal blades during rapid sequence induction of anesthesia in a multicenter cluster randomized trial. One thousand seventy-two adult patients undergoing general anesthesia under emergency conditions and requiring rapid sequence induction were randomly assigned on a weekly basis to either single-use or reusable metal blades (cluster randomization). After induction, a 60-s period was allowed to complete intubation. In the case of failed intubation, a second attempt was performed using the opposite type of blade. The primary endpoint was the rate of failed intubation, and the secondary endpoints were the incidence of complications (oxygen desaturation, lung aspiration, and/or oropharynx trauma) and the Cormack and Lehane score. Both groups were similar in their main characteristics, including the risk factors for difficult intubation. The rate of failed intubation was significantly decreased with single-use metal blades at the first attempt compared with reusable blades (2.8 vs. 5.4%, P < 0.05). In addition, the proportion of grades III and IV in Cormack and Lehane score were also significantly decreased with single-use metal blades (6 vs. 10%, P < 0.05). The global complication rate did not reach statistical significance, although the same trend was noted (6.8% vs. 11.5%, P = not significant). An investigator survey and a measure of illumination pointed that illumination might have been responsible for this result. The single-use metal blade was more efficient than a reusable metal blade in rapid sequence induction of anesthesia.

Effect of Pre-Gamma Irradiation Induction of Metallothionein on potentially Radiation-Induced Toxic Heavy Metals Ions In Rats

International Nuclear Information System (INIS)

El-Shamy, El.

2004-01-01

Metallothionein, which is a cystein-rich metal binding protein, can act as free radical scavenger and involved in resistance to heavy metal toxicity. The induction of synthesis has been shown to protect organs from the toxic effect of radiation. This study aimed to stud the effects of pre-irradiation induction of by heavy metal (Zinc sulfate) on potentially gamma radiation-induced toxic heavy metals ions in rate liver and kidney tissues. Forty eight albino rats were included in this study. They were divided into eight groups each of six animals. Two control groups injected with saline. Two Zinc sulfate-treated groups injected with zinc sulfate, two Irradiated groups exposed to a single dose level (7 Gy) of whole body gamma irradiation and two combined zinc sulfate and irradiation groups injected with zinc sulfate and exposed to whole body gamma irradiation (at dose 7 Gy). Animals of all groups were sacrificed 24 and 48 hours after last either zinc sulfate dose or irradiation. Samples of liver and kidney's tissues were subjected to the following investigations: Estimation of tissue heavy Metals (Zinc, Iron and Copper), and tissue (MT). After irradiation, liver and kidney MT were increased approximately 10-fold and 2-fold respectively after irradiation. Accumulation of zinc and iron in both liver and kidney tissues were detected, while accumulation of copper only in the liver tissues. The pre-irradiation treatment with zinc sulfate (Zn SO4) resulted in highly significant decrease in zinc, iron, and copper levels in both liver and kidney tissues in comparison with irradiation groups. Conclusion, it can be supposed that pre-irradiation injection of ZnSO 4 exerted protective effect against the potentially radiation-induced toxic heavy metals ions through MT induction

Organo-Functionalization of Silicon Nanocrystals Synthesized by Inductively Coupled Plasma Chemical Vapor Deposition

Energy Technology Data Exchange (ETDEWEB)

Lee, Don-Sung; Choe, Dong-Hoe; Jeong, Hyun-Dam [Chonnam National University, Gwangju (Korea, Republic of); Yoo, Seung-Wan; Kim, Jung-Hyung [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

2016-05-15

Octadecyl-terminated silicon nanocrystals (ODE-Si NCs) are obtained via a surface-initiated thermal hydrosilylation reaction on hydride-terminated Si NCs (H-Si NCs). Pristine Si NCs were synthesized at the gram scale by using inductively coupled plasma chemical vapor deposition (ICP-CVD) . The H-Si NCs were produced through a chemical etching process with hydrofluoric acid (HF), ethanol (EtOH), and distilled water (d-H{sub 2}O). The results obtained from X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) indicate that the synthesized Si NCs obtained via ICP-CVD have diamond cubic-structured silicon with a grain size of 10 nm and a densely packed Si NC array consisting of individual NCs. Organo-functionalized Si NCs, i.e., ODE-Si NCs, are well soluble in organic solvent whereas pristine Si NCs synthesized through ICP-CVD are not. The surface chemistry of the ODE-Si NCs was confirmed via Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy ({sup 1}H-NMR), and field emission transmission electron microscopy (FE-TEM). Thereby, these newly synthesized and scalable organo-functionalized Si NCs are applicable as raw materials for practical use in devices by tuning the surface chemistry with various capping molecules.

Magneto-inductive Sensors for Metallic Ropes in Lift Application

Directory of Open Access Journals (Sweden)

Aldo CANOVA

2010-12-01

Full Text Available In this paper an innovative system for the contemporary, selective and reliable control of integrity of multiple rope plants is presented. The system is based on magneto-inductive technology and is composed by a magnetic detector connected to an acquisition system. The core of the detector is constituted by an array of Hall sensors properly placed inside the instrument. After a brief introduction to the Non Destructive Techniques applied to the control of metallic ropes, the first part paper deals with the design and behavior of the detector and the acquisition system. In the second part of the paper a performance analysis for different rope size and experimental results on an elevator plants is presented and discussed.

Radioisotope labeling technique for vapor density measurements of volatile inorganic species

International Nuclear Information System (INIS)

Peterson, E.J.; Caird, J.A.; Hessler, J.P.; Hoekstra, H.R.; Williams, C.W.

1979-01-01

A new method for complexed metal ion vapor density measurement involving labeling the metal ions of interest with a radioactive isotope is described. The isotope chosen in the present work is unstable and leads to emission of a characteristic γ ray. Thus the γ-counting rate was related to the number density of complexed metal ions in the vapor phase. This technique is applicable to the study of any volatile inorganic species, but in the present study has been used to measure vapor densities of complex species in the TbCl 3 -AlCl 3 system by using tracer 160 Tb. 4 figures, 2 tables

Functional speciation of metal-dissolved organic matter complexes by size exclusion chromatography coupled to inductively coupled plasma mass spectrometry and deconvolution analysis

International Nuclear Information System (INIS)

Laborda, Francisco; Ruiz-Begueria, Sergio; Bolea, Eduardo; Castillo, Juan R.

2009-01-01

High performance size exclusion chromatography coupled to inductively coupled plasma mass spectrometry (HP-SEC-ICP-MS), in combination with deconvolution analysis, has been used to obtain multielemental qualitative and quantitative information about the distributions of metal complexes with different forms of natural dissolved organic matter (DOM). High performance size exclusion chromatography coupled to inductively coupled plasma mass spectrometry chromatograms only provide continuous distributions of metals with respect to molecular masses, due to the high heterogeneity of dissolved organic matter, which consists of humic substances as well as biomolecules and other organic compounds. A functional speciation approach, based on the determination of the metals associated to different groups of homologous compounds, has been followed. Dissolved organic matter groups of homologous compounds are isolated from the aqueous samples under study and their high performance size exclusion chromatography coupled to inductively coupled plasma mass spectrometry elution profiles fitted to model Gaussian peaks, characterized by their respective retention times and peak widths. High performance size exclusion chromatography coupled to inductively coupled plasma mass spectrometry chromatograms of the samples are deconvoluted with respect to these model Gaussian peaks. This methodology has been applied to the characterization of metal-dissolved organic matter complexes in compost leachates. The most significant groups of homologous compounds involved in the complexation of metals in the compost leachates studied have been hydrophobic acids (humic and fulvic acids) and low molecular mass hydrophilic compounds. The environmental significance of these compounds is related to the higher biodegradability of the low molecular mass hydrophilic compounds and the lower mobility of humic acids. In general, the hydrophilic compounds accounted for the complexation of around 50% of the leached

Metal-boride phase formation on tungsten carbide (WC-Co) during microwave plasma chemical vapor deposition

Energy Technology Data Exchange (ETDEWEB)

Johnston, Jamin M.; Catledge, Shane A., E-mail: catledge@uab.edu

2016-02-28

Graphical abstract: - Highlights: • A detailed phase analysis after PECVD boriding shows WCoB, CoB and/or W{sub 2}CoB{sub 2}. • EDS of PECVD borides shows boron diffusion into the carbide grain structure. • Nanoindentation hardness and modulus of borides is 23–27 GPa and 600–780 GPa. • Scratch testing shows hard coating with cracking at 40N and spallation at 70N. - Abstract: Strengthening of cemented tungsten carbide by boriding is used to improve the wear resistance and lifetime of carbide tools; however, many conventional boriding techniques render the bulk carbide too brittle for extreme conditions, such as hard rock drilling. This research explored the variation in metal-boride phase formation during the microwave plasma enhanced chemical vapor deposition process at surface temperatures from 700 to 1100 °C. We showed several well-adhered metal-boride surface layers consisting of WCoB, CoB and/or W{sub 2}CoB{sub 2} with average hardness from 23 to 27 GPa and average elastic modulus of 600–730 GPa. The metal-boride interlayer was shown to be an effective diffusion barrier against elemental cobalt; migration of elemental cobalt to the surface of the interlayer was significantly reduced. A combination of glancing angle X-ray diffraction, electron dispersive spectroscopy, nanoindentation and scratch testing was used to evaluate the surface composition and material properties. An evaluation of the material properties shows that plasma enhanced chemical vapor deposited borides formed at substrate temperatures of 800 °C, 850 °C, 900 °C and 1000 °C strengthen the material by increasing the hardness and elastic modulus of cemented tungsten carbide. Additionally, these boride surface layers may offer potential for adhesion of ultra-hard carbon coatings.

Metal-boride phase formation on tungsten carbide (WC-Co) during microwave plasma chemical vapor deposition

International Nuclear Information System (INIS)

Johnston, Jamin M.; Catledge, Shane A.

2016-01-01

Graphical abstract: - Highlights: • A detailed phase analysis after PECVD boriding shows WCoB, CoB and/or W_2CoB_2. • EDS of PECVD borides shows boron diffusion into the carbide grain structure. • Nanoindentation hardness and modulus of borides is 23–27 GPa and 600–780 GPa. • Scratch testing shows hard coating with cracking at 40N and spallation at 70N. - Abstract: Strengthening of cemented tungsten carbide by boriding is used to improve the wear resistance and lifetime of carbide tools; however, many conventional boriding techniques render the bulk carbide too brittle for extreme conditions, such as hard rock drilling. This research explored the variation in metal-boride phase formation during the microwave plasma enhanced chemical vapor deposition process at surface temperatures from 700 to 1100 °C. We showed several well-adhered metal-boride surface layers consisting of WCoB, CoB and/or W_2CoB_2 with average hardness from 23 to 27 GPa and average elastic modulus of 600–730 GPa. The metal-boride interlayer was shown to be an effective diffusion barrier against elemental cobalt; migration of elemental cobalt to the surface of the interlayer was significantly reduced. A combination of glancing angle X-ray diffraction, electron dispersive spectroscopy, nanoindentation and scratch testing was used to evaluate the surface composition and material properties. An evaluation of the material properties shows that plasma enhanced chemical vapor deposited borides formed at substrate temperatures of 800 °C, 850 °C, 900 °C and 1000 °C strengthen the material by increasing the hardness and elastic modulus of cemented tungsten carbide. Additionally, these boride surface layers may offer potential for adhesion of ultra-hard carbon coatings.

Effect of electric arc, gas oxygen torch and induction melting techniques on the marginal accuracy of cast base-metal and noble metal-ceramic crowns.

Science.gov (United States)

Gómez-Cogolludo, Pablo; Castillo-Oyagüe, Raquel; Lynch, Christopher D; Suárez-García, María-Jesús

2013-09-01

The aim of this study was to identify the most appropriate alloy composition and melting technique by evaluating the marginal accuracy of cast metal-ceramic crowns. Seventy standardised stainless-steel abutments were prepared to receive metal-ceramic crowns and were randomly divided into four alloy groups: Group 1: palladium-gold (Pd-Au), Group 2: nickel-chromium-titanium (Ni-Cr-Ti), Group 3: nickel-chromium (Ni-Cr) and Group 4: titanium (Ti). Groups 1, 2 and 3 were in turn subdivided to be melted and cast using: (a) gas oxygen torch and centrifugal casting machine (TC) or (b) induction and centrifugal casting machine (IC). Group 4 was melted and cast using electric arc and vacuum/pressure machine (EV). All of the metal-ceramic crowns were luted with glass-ionomer cement. The marginal fit was measured under an optical microscope before and after cementation using image analysis software. All data was subjected to two-way analysis of variance (ANOVA). Duncan's multiple range test was run for post-hoc comparisons. The Student's t-test was used to investigate the influence of cementation (α=0.05). Uncemented Pd-Au/TC samples achieved the best marginal adaptation, while the worst fit corresponded to the luted Ti/EV crowns. Pd-Au/TC, Ni-Cr and Ti restorations demonstrated significantly increased misfit after cementation. The Ni-Cr-Ti alloy was the most predictable in terms of differences in misfit when either torch or induction was applied before or after cementation. Cemented titanium crowns exceeded the clinically acceptable limit of 120μm. The combination of alloy composition, melting technique, casting method and luting process influences the vertical seal of cast metal-ceramic crowns. An accurate use of the gas oxygen torch may overcome the results attained with the induction system concerning the marginal adaptation of fixed dental prostheses. Copyright © 2013 Elsevier Ltd. All rights reserved.

The tracking of interfaces in an electron-beam vaporizer

International Nuclear Information System (INIS)

Westerberg, K.W.; McClelland, M.A.; Finlayson, B.A.

1993-03-01

A numerical analysis is made of the material and energy flow in an electron beam vaporizer. In this system the energy from an electron beam heats metal confined in a water-cooled crucible. Metal is vaporized from a liquid pool circulating in a shell of its own solid. A modified Galerkin finite element method is used to calculate the flow and temperature fields along with the interface locations. The mesh is parameterized with spines which stretch and pivot as the phase boundaries move. The discretized equations are arranged in an ''arrow'' matrix and solved using the Newton-Raphson method. Results are given for an experimental aluminum vaporizer. The effects of buoyancy and capillary driven flow are included along with the surface contributions of vapor thrust, latent heat, thermal radiation, and crucible contact resistance

Shocked plate metal atom oxidation laser

International Nuclear Information System (INIS)

De Koker, J.G.; Rice, W.W. Jr.; Jensen, R.J.

1975-01-01

A method and apparatus for producing metal atom oxidation lasing wherein an explosively shocked grooved metal plate produces metal vapor jets directed through an appropriate gaseous oxidizer are described. Reaction of the metal vapor with the oxidizer produces molecular species having a population inversion therein. (U.S.)

Apparatus and method for removing mercury vapor from a gas stream

Science.gov (United States)

Ganesan, Kumar [Butte, MT

2008-01-01

A metallic filter effectively removes mercury vapor from gas streams. The filter captures the mercury which then can be released and collected as product. The metallic filter is a copper mesh sponge plated with a six micrometer thickness of gold. The filter removes up to 90% of mercury vapor from a mercury contaminated gas stream.

Catalyst-free growth of InN nanorods by metal-organic chemical vapor deposition

International Nuclear Information System (INIS)

Kim, Min Hwa; Moon, Dae Young; Park, Jinsub; Nanishi, Yasushi; Yi, Gyu-Chul; Yoon, Euijoon

2012-01-01

We demonstrated the growth of catalyst-free InN nanostructures including nanorods on (0001) Al 2 O 3 substrates using metal-organic chemical vapor deposition. As the growth time increased, growth rate along c-direction increased superlinearly with decreasing c-plane area fractions and increasing side wall areas. It was also found that desorption from the sidewalls of InN nanostructures during the InN nanorods formation was one of essential key parameters of the growth mechanism. We propose a growth model to explain the InN nanostructure evolution by considering the side wall desorption and re-deposition of indium at top c-plane surfaces. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

The gas phase emitter effect of lanthanum within ceramic metal halide lamps and its dependence on the La vapor pressure and operating frequency

Energy Technology Data Exchange (ETDEWEB)

Ruhrmann, C.; Hoebing, T.; Bergner, A.; Groeger, S.; Awakowicz, P.; Mentel, J. [Electrical Engineering and Plasma Technology, Ruhr University Bochum, D-44780 Bochum (Germany); Denissen, C.; Suijker, J. [Philips Lighting, Category Professional Lamps, P.O. Box 80020, NL-5600JM Eindhoven (Netherlands)

2015-08-07

The gas phase emitter effect increases the lamp lifetime by lowering the work function and, with it, the temperature of the tungsten electrodes of metal halide lamps especially for lamps in ceramic vessels due to their high rare earth pressures. It is generated by a monolayer on the electrode surface of electropositive atoms of certain emitter elements, which are inserted into the lamp bulb by metal iodide salts. They are vaporized, dissociated, ionized, and deposited by an emitter ion current onto the electrode surface within the cathodic phase of lamp operation with a switched-dc or ac-current. The gas phase emitter effect of La and the influence of Na on the emitter effect of La are studied by spatially and phase-resolved pyrometric measurements of the electrode tip temperature, La atom, and ion densities by optical emission spectroscopy as well as optical broadband absorption spectroscopy and arc attachment images by short time photography. An addition of Na to the lamp filling increases the La vapor pressure within the lamp considerably, resulting in an improved gas phase emitter effect of La. Furthermore, the La vapor pressure is raised by a heating of the cold spot. In this way, conditions depending on the La vapor pressure and operating frequency are identified, at which the temperature of the electrodes becomes a minimum.

A radiotracer study on the volatilization and transport effects of thermochemical reagents used in the analysis of alumina powders by slurry electrothermal vaporization inductively coupled plasma mass spectrometry

International Nuclear Information System (INIS)

Peschel, Birgit U.; Herdering, Wilhelm; Broekaert, Jose A.C.

2007-01-01

A neutron-activated Al 2 O 3 powder SRM 699 (NIST) containing the γ-radiation emitting radionuclides 51 Cr, 59 Fe, 60 Co and 65 Zn has been used to study the influence of thermochemical reagents on the volatilization and transport efficiency for these trace elements in electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) of Al 2 O 3 powders. From the signals in the γ-spectra for the radiotracers it has been found that less than 2% of the elements Cr, Fe, Co and Zn is left back in a graphite furnace from Al 2 O 3 powders at 2200 deg. C even without addition of a thermochemical reagent and the latter even was found to decrease the volatilization efficiencies. The recovery for the radiotracers on filters at the end of the transport tube as measured from the signals in the γ-spectra, however, was found to increase in most cases (i.e. from about 10% to more than 20%) when Pd(NO 3 ) 2 , Pd(NO 3 ) 2 + Mg(NO 3 ) 2 , PdCl 2 , IrCl 3 , SnCl 2 , AgCl, NaF, NH 4 Cl and NH 4 F were added at amounts generally used in electrothermal vaporization inductively coupled plasma mass spectrometry. However, when adding higher amounts as stoichiometrically required for a complete halogenation of the sample matrix in the case of AgCl, C 8 F 15 O 2 Na, IrCl 3 or PdCl 2 the transport efficiencies considerably decrease again. As shown in the case of NH 4 Cl the amount of thermochemical reagent used has to be optimized so as to obtain maximum analyte transport efficiencies. A comparison of the influence of NH 4 Cl on the transport efficiencies with its influence on the ETV-ICP-MS signals for Fe demonstrates the importance of transport efficiency changes for the effects of thermochemical reagents in electrothermal vaporization inductively coupled plasma mass spectrometry

Profiling metals in Cordyceps sinensis by using inductively coupled plasma mass spectrometry.

Science.gov (United States)

Wei, Xin; Hu, Hankun; Zheng, Baogeng; Arslan, Zikri; Huang, Hung-Chung; Mao, Weidong; Liu, Yi-Ming

2017-01-28

Cordyceps sinensis ( C. sinensis ) is a natural product that has diverse nutritional and medicinal values. Since the availability of natural C. sinensis becomes limited its authentication and quality control is of high significance. Herein we report on profiling of metals in C. sinensis by using inductively coupled plasma mass spectrometry (ICP-MS). The analysis reveals that C. sinensis contains a wide array of essential elements, including P, Mg, Zn, Cu, Fe, etc. Toxic metals detected are Cd, Pb, and As. In all five samples analyzed Pb contents are below 2.0 ppm. Arsenic level in C. sinensis caterpillar is significantly higher than that in its mycelium and varies from 3.0 to 32 ppm likely due to soil contamination. It's for the first time demonstrated in this work that clustering analysis on the proposed metal profiles consisting of 24 elements is very useful to identify "abnormal" C. sinensis samples, thus adding another dimension to the effective means for authentication and quality assessment of this highly demanded previous natural product.

Determination of mercury in coal by isotope dilution cold-vapor generation inductively coupled plasma mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Long, S.E.; Kelly, W.R.

2002-04-01

A method based on isotope dilution cold-vapor inductively coupled plasma mass spectrometry (ID-CV-ICPMS) has been developed for high-accuracy determinations of mercury in bituminous and sub-bituminous coals. A closed-system digestion process employing a Carius tube is used to completely oxidize the coal matrix and chemically equilibrate the mercury in the sample with a Hg-201 isotopic spike. The digestates are diluted with high-purity quartz-distilled water, and the mercury is released as a vapor by reduction with tin chloride. Measurements of Hg-201/Hg-202 isotope ratios are made using a quadrupole ICPMS system in time-resolved analysis mode. The new method has some significant advantages over existing methods. The instrument detection limit is less than 1 pg/mL. The average blank (n = 17) is 30 pg, which is roughly 1 order of magnitude lower than the equivalent microwave digestion procedure. The detection limit in coal is blank limited and is similar to 40 pg/g. Memory effects are very low. The relative reproducibility of the analytical measurements is similar to 0.5% for mercury concentrations in the range 10-150 ng/g. The method has been used to measure mercury concentrations in six coal reference materials, SRM 1632b (77.4 ng/g), SRM 1632c (94.3 ng/g), BCR 40 (433.2 ng/g), BCR 180 (125.0 ng/g), BCR 181 (135.8 ng/g), and SARM 20 (252.6 ng/g), as well as a coal fly ash, SRM 1633b (143.1 ng/g). The method is equally applicable to other types of fossil fuels including both crude and refined oils.

Surface engineering glass-metal coatings designed for induction heating of ceramic components

International Nuclear Information System (INIS)

Khan, Amir Azam; Labbe, Jean Claude

2014-01-01

The term Surface Engineering is of relatively recent origin and use, however, the use of coatings and treatments to render surfaces of materials more suitable for certain application or environment is not new. With the advent of Vacuum Technology, Surface Engineering has gained a whole new impetus, whereby expensive materials with adequate mechanical, chemical and thermal properties are being coated or treated on their surfaces in order to achieve what is called as Surface Engineered materials. The present paper presents an overview of recent achievements in Surface Engineering and gives a detailed view of a specific application where glass-metal composite coatings were deposited on ceramic components in order to render them sensitive to induction heating. Sintered glaze coatings containing silver particles in appropriate concentration can be used for the induction heating of porcelain. Mixtures of glass ceramic powders with silver are used to prepare self-transfer patterns, which are deposited over porcelain. Several configurations of these coatings, which are aesthetic to start with, are employed and heating patterns are recorded. The microstructure of these coatings is discussed in relation to the heating ability by a classical household induction system. The results show that this technique is practical and commercially viable

Direct determination of cadmium in foods by solid sampling electrothermal vaporization inductively coupled plasma mass spectrometry using a tungsten coil trap

Science.gov (United States)

Zhang, Ying; Mao, Xuefei; Liu, Jixin; Wang, Min; Qian, Yongzhong; Gao, Chengling; Qi, Yuehan

2016-04-01

In this work, a solid sampling device consisting of a tungsten coil trap, porous carbon vaporizer and on-line ashing furnace of a Ni-Cr coil was interfaced with inductively coupled plasma mass spectrometry (ICP-MS). A modified double gas circuit system was employed that was composed of carrier and supplemental gas lines controlled by separate gas mass flow controllers. For Cd determination in food samples using the assembled solid sampling ICP-MS, the optimal ashing and vaporization conditions, flow rate of the argon-hydrogen (Ar/H2) (v:v = 24:1) carrier gas and supplemental gas, and minimum sampling mass were investigated. Under the optimized conditions, the limit of quantification was 0.5 pg and the relative standard deviation was within a 10.0% error range (n = 10). Furthermore, the mean spiked recoveries for various food samples were 99.4%-105.9% (n = 6). The Cd concentrations measured by the proposed method were all within the certified values of the reference materials or were not significantly different (P > 0.05) from those of the microwave digestion ICP-MS method, demonstrating the good accuracy and precision of the solid sampling ICP-MS method for Cd determination in food samples.

Induction by mercury compounds of brain metallothionein in rats: Hg{sup 0} exposure induces long-lived brain metallothionein

Energy Technology Data Exchange (ETDEWEB)

Yasutake, Akira; Nakano, Atsuhiro [Biochemistry Section, National Institute for Minamata Disease, Kumamoto (Japan); Hirayama, Kimiko [Kumamoto University, College of Medical Science (Japan)

1998-03-01

Metallothionein (MT) is one of the stress proteins which can easily be induced by various kind of heavy metals. However, MT in the brain is difficult to induce because of blood-brain barrier impermeability to most heavy metals. In this paper, we have attempted to induce brain MT in rats by exposure to methylmercury (MeHg) or metallic mercury vapor, both of which are known to penetrate the blood-brain barrier and cause neurological damage. Rats treated with MeHg (40 {mu}mol/kg per day x 5 days, p.o.) showed brain Hg levels as high as 18 {mu}g/g with slight neurological signs 10 days after final administration, but brain MT levels remained unchanged. However, rats exposed to Hg vapor for 7 days showed 7-8 {mu}g Hg/g brain tissue 24 h after cessation of exposure. At that time brain MT levels were about twice the control levels. Although brain Hg levels fell gradually with a half-life of 26 days, MT levels induced by Hg exposure remained unchanged for >2 weeks. Gel fractionation revealed that most Hg was in the brain cytosol fraction and thus bound to MT. Hybridization analysis showed that, despite a significant increase in MT-I and -II mRNA in brain, MT-III mRNA was less affected. Although significant Hg accumulation and MT induction were observed also in kidney and liver of Hg vapor-exposed rats, these decreased more quickly than in brain. The long-lived MT in brain might at least partly be accounted for by longer half-life of Hg accumulated there. The present results showed that exposure to Hg vapor might be a suitable procedure to provide an in vivo model with enhanced brain MT. (orig.) With 4 figs., 1 tab., 27 refs.

Induction Brazing

DEFF Research Database (Denmark)

Henningsen, Poul

, or if the hottest area is located outside the joint interface, a number of defects may appear: the braze metal may flow away from the joint, the flux may burn off, poor binding of the braze metal may appear or the braze metal may be overheated. Joint geometry as well as electro-magnetic properties of the work piece...... presents a combined numerical and experimental method for determination of appropriate/optimiged coil geometry and position in induction brazing tube-to-plate joints of different ratios between tube and plate thickness and different combinations of the materials stainless steel, brass and copper....... The method has proven to give successful results in brazing tube-plate joints of copper-brass, copper-stainless steel, stainless steel-brass, and stainless steel-stainless steel. A new design of an adjustable flux concentrator for induction heating tube-to-plate joints is proposed and tested on a variety...

Induction of temperate cyanophage AS-1 by heavy metal – copper

Directory of Open Access Journals (Sweden)

Chu Tin-Chun

2006-02-01

Full Text Available Abstract Background It has been reported that some marine cyanophage are temperate and can be induced from a lysogenic phase to a lytic phase by different agents such as heavy metals. However, to date no significant reports have focused on the temperate nature of freshwater cyanophage/cyanobacteria. Previous experiments with cyanophage AS-1 and cyanobacteria Anacystis nidulans have provided some evidence that AS-1 may have a lysogenic life cycle in addition to the characterized lytic cycle. Results In this study, the possible temperate A. nidulans was treated with different concentrations of heavy metal-copper. CuSO4 with concentrations of 3.1 × 10-3 M, 3.1 × 10-4 M, 3.1 × 10-5 M and 3.1 × 10-6 M were used to detect the induction of AS-1 from A. nidulans. The population of the host, unicellular cyanobacteria Anacystis nidulans, was monitored by direct count and turbidity while the amount of virus produced was derived from plaque forming units (PFU by a direct plating method. The ratio of AS-1 release from A. nidulans was also determined. From these results it appears that AS-1 lysogenic phage can be induced by copper at concentrations from 3.1 × 10-6 M to 3.1 × 10-4 M. Maximal phage induction occurred at 6 hours after addition of copper, with an optimal concentration of 3.1 × 10-6 M. Conclusion Cu2+ is a significant inducer for lysogenic cyanobacterial cells and consequently would be a potential control agent in the cyanobacteria population in fresh water ecosystems.

InAs film grown on Si(111) by metal organic vapor phase epitaxy

International Nuclear Information System (INIS)

Caroff, P; Jeppsson, M; Mandl, B; Wernersson, L-E; Wheeler, D; Seabaugh, A; Keplinger, M; Stangl, J; Bauer, G

2008-01-01

We report the successful growth of high quality InAs films directly on Si(111) by Metal Organic Vapor Phase Epitaxy. A nearly mirror-like and uniform InAs film is obtained at 580 0 C for a thickness of 2 μm. We measured a high value of the electron mobility of 5100 cm 2 /Vs at room temperature. The growth is performed using a standard two-step procedure. The influence of the nucleation layer, group V flow rate, and layer thickness on the electrical and morphological properties of the InAs film have been investigated. We present results of our studies by Atomic Force Microscopy, Scanning Electron Microscopy, electrical Hall/van der Pauw and structural X-Ray Diffraction characterization

Homostructured ZnO-based metal-oxide-semiconductor field-effect transistors deposited at low temperature by vapor cooling condensation system

Energy Technology Data Exchange (ETDEWEB)

Lin, Tzu-Shun [Institute of Nanotechnology and Microsystems Engineering, National Cheng Kung University, 701 Tainan, Taiwan, ROC (China); Lee, Ching-Ting, E-mail: ctlee@ee.ncku.edu.tw [Institute of Nanotechnology and Microsystems Engineering, National Cheng Kung University, 701 Tainan, Taiwan, ROC (China); Institute of Microelectronics, Department of Electrical Engineering, Advanced Optoelectronic Technology Center, National Cheng Kung University, 701 Tainan, Taiwan, ROC (China)

2015-11-01

Highlights: • The vapor cooling condensation system was designed and used to deposit homostructured ZnO-based metal-oxide-semiconductor field-effect transistors. • The resulting homostructured ZnO-based MOSFETs operated at a reverse voltage of −6 V had a very low gate leakage current of 24 nA. • The associated I{sub DSS} and the g{sub m(max)} were 5.64 mA/mm and 1.31 mS/mm, respectively. - Abstract: The vapor cooling condensation system was designed and used to deposit homostructured ZnO-based metal-oxide-semiconductor field-effect transistors (MOSFETs) on sapphire substrates. Owing to the high quality of the deposited, various ZnO films and interfaces, the resulting MOSFETs manifested attractive characteristics, such as the low gate leakage current of 24 nA, the low average interface state density of 2.92 × 10{sup 11} cm{sup −2} eV{sup −1}, and the complete pinch-off performance. The saturation drain–source current, the maximum transconductance, and the gate voltage swing of the resulting homostructured ZnO-based MOSFETs were 5.64 mA/mm, 1.31 mS/mm, and 3.2 V, respectively.

Contamination spike simulation and measurement in a clean metal vapor laser

International Nuclear Information System (INIS)

Lin, C.E.; Yang, C.Y.

1990-01-01

This paper describes a new method for the generation of contamination-induced voltage spikes in a clean metal vapor laser. The method facilitates the study of the characteristics of this troublesome phenomenon in laser systems. Analysis of these artificially generated dirt spikes shows that the breakdown time of the laser tube is increased when these spike appear. The concept of a Townsend discharge is used to identify the parameter which changes the breakdown time of the discharges. The residual ionization control method is proposed to generate dirt spikes in a clean laser. Experimental results show that a wide range of dirt spike magnitudes can be obtained by using the proposed method. The method provides easy and accurate control of the magnitude of the dirt spike, and the laser tube does not become polluted. Results based on the measurements can be used in actual laser systems to monitor the appearance of dirt spikes and thus avoid the danger of thyratron failure

Optical emission spectroscopy of metal vapor dominated laser-arc hybrid welding plasma

International Nuclear Information System (INIS)

Ribic, B.; DebRoy, T.; Burgardt, P.

2011-01-01

During laser-arc hybrid welding, plasma properties affect the welding process and the weld quality. However, hybrid welding plasmas have not been systematically studied. Here we examine electron temperatures, species densities, and electrical conductivity for laser, arc, and laser-arc hybrid welding using optical emission spectroscopy. The effects of arc currents and heat source separation distances were examined because these parameters significantly affect weld quality. Time-average plasma electron temperatures, electron and ion densities, electrical conductivity, and arc stability decrease with increasing heat source separation distance during hybrid welding. Heat source separation distance affects these properties more significantly than the arc current within the range of currents considered. Improved arc stability and higher electrical conductivity of the hybrid welding plasma result from increased heat flux, electron temperatures, electron density, and metal vapor concentrations relative to arc or laser welding.

Deposition of controllable preferred orientation silicon films on glass by inductively coupled plasma chemical vapor deposition

International Nuclear Information System (INIS)

Li Junshuai; Wang Jinxiao; Yin Min; Gao Pingqi; He Deyan; Chen Qiang; Li Yali; Shirai, Hajime

2008-01-01

An inductively coupled plasma (ICP) system with the adjustable distance between the inductance coil and substrates was designed to effectively utilize the spatial confinement of ICP discharge, and then control the gas-phase transport process. The effects of the gas phase processes on the crystallinity and preferred orientation of silicon films deposited on glass were systematically investigated. The investigation was conducted in the ICP-chemical vapor deposition process with the precursor gas of a SiH 4 /H 2 mixture at a substrate temperature of 350 deg. Highly crystallized silicon films with different preferred orientations, (111) or (220), could be selectively deposited by adjusting the SiH 4 dilution ratio [R=[SiH 4 ]/([SiH 4 ]+[H 2 ])] or total working pressure. When the total working pressure is 20 Pa, the crystallinity of the silicon films increases with the increase of the SiH 4 dilution ratio, while the preferred orientation was changed from (111) to (220). In the case of the fixed SiH 4 dilution (10%), the silicon film with I (220) /I (111) of about 3.5 and Raman crystalline fraction of about 89.6% has been deposited at 29.7 nm/min when the total working pressure was increased to 40 Pa. At the fixed SiH 4 partial pressure of 2 Pa, the film crystallinity decreases and the preferred orientation is always (111) with increasing the H 2 partial pressure from 18 to 58 Pa. Atomic force microscope reveals that the film deposited at a relatively high H 2 partial pressure has a very rough surface caused by the devastating etching of H atoms to the silicon network

Tuning of electrical and structural properties of indium oxide films grown by metal organic chemical vapor deposition

International Nuclear Information System (INIS)

Wang, Ch.Y.; Cimalla, V.; Romanus, H.; Kups, Th.; Niebelschuetz, M.; Ambacher, O.

2007-01-01

Tuning of structural and electrical properties of indium oxide (In 2 O 3 ) films by means of metal organic chemical vapor deposition is demonstrated. Phase selective growth of rhombohedral In 2 O 3 (0001) and body-centered cubic In 2 O 3 (001) polytypes on (0001) sapphire substrates was obtained by adjusting the substrate temperature and trimethylindium flow rate. The specific resistance of the as-grown films can be tuned by about two orders of magnitude by varying the growth conditions

Some novel design features of the LBL metal vapor vacuum arc ion sources

International Nuclear Information System (INIS)

MacGill, R.A.; Brown, I.G.; Galvin, J.E.

1990-01-01

The family of MEVVA (metal vapor vacuum arc) high current metal ion sources developed at LBL over the past several years has grown to include a number of different source versions with a wide range of some of the design and operational parameters. The MicroMEVVA source is a particularly compact version, about 2 cm diam and 10 cm long, while the MEVVA IV weighs some 30 kG. MEVVAs IV and V incorporate multiple cathode assemblies (16 and 18 separate cathodes, respectively), and the operating cathode can be switched rapidly and without downtime. The new MEVVA V embodiment is quite compact considering its broad beam (10 cm), high voltage (100 kV), and multiple cathode features. The large-area extractor grids used in MEVVA V were fabricated using a particularly simple technique, and they are clamped into position and can thus be changed simply and quickly. The electrical system used to drive the arc is particularly simple and incorporates several attractive features. In this article we review and describe a number of the mechanical and electrical design features that have been developed for these sources

Metal impurity injection into DIVA plasmas with a Q-switched laser beam

International Nuclear Information System (INIS)

Yamauchi, Toshihiko; Nagami, Masayuki; Sengoku, Seio; Kumagai, Katsuaki

1978-08-01

Metal impurity injection into DIVA plasmas with a Q-switched ruby laser beam is described. Metal materials used are aluminium and gold. The Q-switched laser beam is incident onto a thin metal film thickness about 0.2 μm coated on pyrex glass plate surface. The metal film is vaporized by the laser beam and injected into DIVA plasma. The laser-beam injection method has advantages of sharp profile of vaporized metal, easy control of vaporized metal quantity and injection rate control of metal vapor. (author)

Vertically aligned Si nanocrystals embedded in amorphous Si matrix prepared by inductively coupled plasma chemical vapor deposition (ICP-CVD)

Energy Technology Data Exchange (ETDEWEB)

Nogay, G. [Department of Physics, Middle East Technical University (METU), Ankara 06800 (Turkey); Center of Solar Energy Research and Application (GÜNAM), Middle East Technical University (METU), Ankara 06800 (Turkey); Saleh, Z.M., E-mail: zaki.saleh@aauj.edu [Center of Solar Energy Research and Application (GÜNAM), Middle East Technical University (METU), Ankara 06800 (Turkey); Department of Physics, Arab American University–Jenin (AAUJ), Jenin, Palestine (Country Unknown); Özkol, E. [Center of Solar Energy Research and Application (GÜNAM), Middle East Technical University (METU), Ankara 06800 (Turkey); Department of Chemical Engineering, Middle East Technical University (METU), Ankara 06800 (Turkey); Turan, R. [Department of Physics, Middle East Technical University (METU), Ankara 06800 (Turkey); Center of Solar Energy Research and Application (GÜNAM), Middle East Technical University (METU), Ankara 06800 (Turkey)

2015-06-15

Highlights: • Inductively-coupled plasma is used for nanostructured silicon at room temperature. • Low temperature deposition allows device processing on various substrates. • Deposition pressure is the most effective parameter in controlling nanostructure. • Films consist of quantum dots in a-Si matrix and exhibit columnar vertical growth. • Films are porous to oxygen infusion along columnar grain boundaries. - Abstract: Vertically-aligned nanostructured silicon films are deposited at room temperature on p-type silicon wafers and glass substrates by inductively-coupled, plasma-enhanced chemical vapor deposition (ICPCVD). The nanocrystalline phase is achieved by reducing pressure and increasing RF power. The crystalline volume fraction (X{sub c}) and the size of the nanocrystals increase with decreasing pressure at constant power. Columnar growth of nc-Si:H films is observed by high resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM). The films exhibit cauliflower-like structures with high porosity that leads to slow but uniform oxidation after exposure to air at room temperature. Films deposited at low pressures exhibit photoluminescence (PL) signals that may be deconvoluted into three distinct Gaussian components: 760–810, 920–935, and 990–1000 nm attributable to the quantum confinement and interface defect states. Hydrogen dilution is manifested in significant enhancement of the PL, but it has little effect on the nanocrystal size and X{sub c}.

On the relation between the ratio of energy of vaporization to activation energy for flow and physical properties of liquid metals

International Nuclear Information System (INIS)

Dutt, N.V.K.; Ravikumar, Y.V.L.; Prasad, D.H.L.

1993-01-01

A relation between the ratio of energy of vaporization (Esub(vap) to the activation energy for flow (Esub(vis)) and the ratio of melting point (T m ) to the critical temperature (T c ) has been developed for liquid metals, and is shown to be superior to the examinations from Eyring theory. (author). 12 refs

Determination of metals content from wines by inductively coupled plasma mass spectrometry

International Nuclear Information System (INIS)

Iordache, Andreea-Maria; Geana, Elisabeta-Irina

2009-01-01

Full text: Wine is a widely consumed beverage with thousands of years of tradition. Wine composition strongly determines its quality besides having a great relevance on wine characterization, tipyfication and frauds detection. Wine composition is influenced by many and diverse factors corresponding to the specific production area, such as grape variety, soil and climate, culture, yeast, winemaking practices, transport and storage. Daily consumption of wine in moderate quantities contributes significantly to the requirements of the human organism for essential elements such as Cr, Cu, Zn, Fe, Mn, Co, Ni and Sr. On the other hand, several metals, such as Pb and Cd , are known to be potentially toxic. The objective of this work was to develop a method to determine the metals content in wine samples from Romania. Three samples of difference white wines available in the supermarket was analyzed for identify the presence of: Cr, Cu, Zn, Fe, Mn, Pb, Cd, Co, Ni and Sr by inductively coupled plasma mass spectrometry (ICP-MS). (authors)

High power uv metal vapor ion lasers pumped by thermal energy charge exchange

International Nuclear Information System (INIS)

Kan, T.

1975-01-01

The requirement for efficient and scalable laser sources for laser isotope separation (LIS) has recently been brought into sharp focus. The lack of suitable coherent sources is particularly severe in the uv, a spectral region of interest for more efficient and advanced isotope separation schemes. This report explores the general class of metal vapor ion lasers pumped by thermal energy charge exchange (TECX) as possible scalable coherent sources for LIS with the following potential characteristics: (1) availability of discrete wavelengths spanning the wavelength region between 2000 A less than lambda less than 8000 A, (2) pulsed or cw operation in the multi-kilowatt average power levels, (3) overall device efficiencies approaching one percent, and (4) the engineering of practical laser devices using relatively benign electron beam technology. (U.S.)

Properties of amorphous silicon thin films synthesized by reactive particle beam assisted chemical vapor deposition

International Nuclear Information System (INIS)

Choi, Sun Gyu; Wang, Seok-Joo; Park, Hyeong-Ho; Jang, Jin-Nyoung; Hong, MunPyo; Kwon, Kwang-Ho; Park, Hyung-Ho

2010-01-01

Amorphous silicon thin films were formed by chemical vapor deposition of reactive particle beam assisted inductively coupled plasma type with various reflector bias voltages. During the deposition, the substrate was heated at 150 o C. The effects of reflector bias voltage on the physical and chemical properties of the films were systematically studied. X-ray diffraction and Raman spectroscopy results showed that the deposited films were amorphous and the films under higher reflector voltage had higher internal energy to be easily crystallized. The chemical state of amorphous silicon films was revealed as metallic bonding of Si atoms by using X-ray photoelectron spectroscopy. An increase in reflector voltage induced an increase of surface morphology of films and optical bandgap and a decrease of photoconductivity.

Thin films of mixed metal compounds

Science.gov (United States)

Mickelsen, Reid A.; Chen, Wen S.

1985-01-01

A compositionally uniform thin film of a mixed metal compound is formed by simultaneously evaporating a first metal compound and a second metal compound from independent sources. The mean free path between the vapor particles is reduced by a gas and the mixed vapors are deposited uniformly. The invention finds particular utility in forming thin film heterojunction solar cells.

Theoretical and Experimental Analysis of an Induction Planar Actuator with Different Secondaries—A Planar Driver Application for Metallic Surface Inspection

Science.gov (United States)

Treviso, Felipe; Silveira, Marilia A.; Flores Filho, Aly F.; Dorrell, David G.

2016-01-01

This paper presents a study on an induction planar actuator concept. The device uses the same principles as a linear induction motor in which the interaction between a travelling magnetic field and a conducting surface produces eddy currents that leads to the generation of a thrust force and can result in movement over a metallic surface. This can benefit the inspection of metallic surfaces based on the driving platform provided by the induction planar actuator. Equations of the magnetic and electric fields are presented and, by means of these equations, the forces involved were calculated. The behaviour of thrust and normal forces was analysed through the equations and by numerical models, and compared with the results obtained by measurements on a device prototype built in the laboratory as part of the study. With relation to the surface under inspection that forms the secondary, three cases were analysed: (1) a double-layered secondary formed by aluminium and ferromagnetic slabs; (2) a single aluminium layer and (3) a single ferromagnetic layer. Theoretical and measured values of thrust and normal forces showed good correlation. PMID:27007377

Mercury uptake in vivo by normal and acatalasemic mice exposed to metallic mercury vapor (203Hg degrees) and injected with metallic mercury or mercuric chloride (203HgCl2)

International Nuclear Information System (INIS)

Ogata, M.; Kenmotsu, K.; Hirota, N.; Meguro, T.; Aikoh, H.

1985-01-01

Levels of mercury in the brain and liver of acatalasemic mice immediately following exposure to metallic mercury vapor or injection of metallic mercury were higher than those found in normal mice. Acatalasemic mice had decreased levels of mercury in the blood and kidneys when the levels were compared with those of normal mice, which indicated that catalase plays a role in oxidizing and taking up mercury. Thus, the brain/blood or liver/blood ratio of mercury concentration in acatalasemic mice was significantly higher than that of normal mice. These results suggest that metallic mercury in the blood easily passed through the blood-brain or blood-liver barrier. The levels of mercury distribution to the kidneys of normal and acatalasemic mice, 1 hr after injection of mercuric chloride solution, were higher than that of normal and acatalasemic mice, respectively, 1 hr after injection of metallic mercury

Water Vapor Permeation of Metal Oxide/Polymer Coated Plastic Films

Science.gov (United States)

Numata, Yukihiro; Oya, Toshiyuki; Kuwahara, Mitsuru; Ito, Katsuya

Barrier performance to water vapor permeation of ceramic coated layers deposited on flexible polymer films is of great interest to food packaging, medical device packaging and flat panel display industries. In this study, a new type film in which a ceramic layer is deposited on a polymer coated film was proposed for lower water vapor permeation. It is important how to control interfacial properties between each layer and film for good barrier performance. Several kinds of polymer coated materials were prepared for changing surface free energy of the films before and after depositing the ceramic layer. The ceramic layer, which is composed of mixed material of SiO2 and Al2O3, was adopted under the same conditions. The following results were obtained; 1) Water vapor permeation is not related to the surface energy of polymer coated films, 2) After depositing the ceramic layer, however, a strong correlation is observed between the water vapor permeation and surface free energy. 3) The phenomenon is considered that the polarity of the polymer layers plays a key role in changing the structure of ceramic coated layers.

Statistical analysis of dimer formation in supersaturated metal vapor based on molecular dynamics simulation

Science.gov (United States)

Korenchenko, Anna E.; Vorontsov, Alexander G.; Gelchinski, Boris R.; Sannikov, Grigorii P.

2018-04-01

We discuss the problem of dimer formation during the homogeneous nucleation of atomic metal vapor in an inert gas environment. We simulated nucleation with molecular dynamics and carried out the statistical analysis of double- and triple-atomic collisions as the two ways of long-lived diatomic complex formation. Close pair of atoms with lifetime greater than the mean time interval between atom-atom collisions is called a long-lived diatomic complex. We found that double- and triple-atomic collisions gave approximately the same probabilities of long-lived diatomic complex formation, but internal energy of the resulted state was essentially lower in the second case. Some diatomic complexes formed in three-particle collisions are stable enough to be a critical nucleus.

Matrix effects in inductively coupled plasma mass spectrometry

International Nuclear Information System (INIS)

Chen, Xiaoshan.

1995-01-01

The inductively coupled plasma is an electrodeless discharge in a gas (usually Ar) at atmospheric pressure. Radio frequency energy generated by a RF power source is inductively coupled to the plasma gas through a water cooled load coil. In ICP-MS the open-quotes Fasselclose quotes TAX quartz torch commonly used in emission is mounted horizontally. The sample aerosol is introduced into the central flow, where the gas kinetic temperature is about 5000 K. The aerosol is vaporized, atomized, excited and ionized in the plasma, and the ions are subsequently extracted through two metal apertures (sampler and skimmer) into the mass spectrometer. In ICP-MS, the matrix effects, or non-spectroscopic interferences, can be defined as the type of interferences caused by dissolved concomitant salt ions in the solution. Matrix effects can be divided into two categories: (1) signal drift due to the deposition of solids on the sampling apertures; and/or (2) signal suppression or enhancement by the presence of the dissolved salts. The first category is now reasonably understood. The dissolved salts, especially refractory oxides, tend to deposit on the cool tip of the sampling cone. The clogging of the orifices reduces the ion flow into the ICP-MS, lowers the pressure in the first stage of ICP-MS, and enhances the level of metal oxide ions. Because the extent of the clogging increases with the time, the signal drifts down. Even at the very early stage of the development of ICP-MS, matrix effects had been observed. Houk et al. found out that the ICP-MS was not tolerant to solutions containing significant amounts of dissolved solids

Use of oxidative and reducing vapor generation for reducing the detection limits of iodine in biological samples by inductively coupled plasma atomic emission spectrometry

International Nuclear Information System (INIS)

Vtorushina, Eh.A.; Saprykin, A.I.; Knapp, G.

2009-01-01

Procedures of microwave combustion in an oxygen flow and microwave acid decomposition of biological samples were optimized for the subsequent determination of iodine. A new method was proposed for the generation of molecular iodine from periodate iona using hydrogen peroxide as a reductant. Procedures were developed for determining iodine in biological samples by inductively coupled plasma atomic emission spectrometry (ICP-AES) using oxidative and reducing vapor generation; these allowed the detection limit for iodine to be lowered by 3-4 orders of magnitude. The developed procedures were used to analyze certified reference materials of milk (Skim Milk Powder BCR 150) and seaweed (Sea Lettuce BCR 279) and a Supradyn vitamin complex

Thermodynamic analysis of trimethylgallium decomposition during GaN metal organic vapor phase epitaxy

Science.gov (United States)

Sekiguchi, Kazuki; Shirakawa, Hiroki; Chokawa, Kenta; Araidai, Masaaki; Kangawa, Yoshihiro; Kakimoto, Koichi; Shiraishi, Kenji

2018-04-01

We analyzed the decomposition of Ga(CH3)3 (TMG) during the metal organic vapor phase epitaxy (MOVPE) of GaN on the basis of first-principles calculations and thermodynamic analysis. We performed activation energy calculations of TMG decomposition and determined the main reaction processes of TMG during GaN MOVPE. We found that TMG reacts with the H2 carrier gas and that (CH3)2GaH is generated after the desorption of the methyl group. Next, (CH3)2GaH decomposes into (CH3)GaH2 and this decomposes into GaH3. Finally, GaH3 becomes GaH. In the MOVPE growth of GaN, TMG decomposes into GaH by the successive desorption of its methyl groups. The results presented here concur with recent high-resolution mass spectroscopy results.

Metallic 1T phase source/drain electrodes for field effect transistors from chemical vapor deposited MoS{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Kappera, Rajesh; Voiry, Damien; Jen, Wesley; Acerce, Muharrem; Torrel, Sol; Chhowalla, Manish, E-mail: manish1@rci.rutgers.edu [Materials Science and Engineering, Rutgers University, 607 Taylor Road, Piscataway, New Jersey 08854 (United States); Yalcin, Sibel Ebru; Branch, Brittany; Gupta, Gautam; Mohite, Aditya D. [MPA-11 Materials Synthesis and Integrated Devices, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Lei, Sidong; Chen, Weibing; Najmaei, Sina; Lou, Jun; Ajayan, Pulickel M. [Mechanical Engineering and Materials Science Department, Rice University, Houston, Texas 77005 (United States)

2014-09-01

Two dimensional transition metal dichalcogenides (2D TMDs) offer promise as opto-electronic materials due to their direct band gap and reasonably good mobility values. However, most metals form high resistance contacts on semiconducting TMDs such as MoS{sub 2}. The large contact resistance limits the performance of devices. Unlike bulk materials, low contact resistance cannot be stably achieved in 2D materials by doping. Here we build on our previous work in which we demonstrated that it is possible to achieve low contact resistance electrodes by phase transformation. We show that similar to the previously demonstrated mechanically exfoliated samples, it is possible to decrease the contact resistance and enhance the FET performance by locally inducing and patterning the metallic 1T phase of MoS{sub 2} on chemically vapor deposited material. The device properties are substantially improved with 1T phase source/drain electrodes.

Laterally Stitched Heterostructures of Transition Metal Dichalcogenide: Chemical Vapor Deposition Growth on Lithographically Patterned Area

KAUST Repository

Li, Henan

2016-10-31

Two-dimensional transition metal dichalcogenides (TMDCs) have shown great promise in electronics and optoelectronics due to their unique electrical and optical properties. Heterostructured TMDC layers such as the laterally stitched TMDCs offer the advantages of better electronic contact and easier band offset tuning. Here, we demonstrate a photoresist-free focused ion beam (FIB) method to pattern as-grown TMDC monolayers by chemical vapor deposition, where the exposed edges from FIB etching serve as the seeds for growing a second TMDC material to form desired lateral heterostructures with arbitrary layouts. The proposed lithographic and growth processes offer better controllability for fabrication of the TMDC heterostrucuture, which enables the construction of devices based on heterostructural monolayers. © 2016 American Chemical Society.

An inverted cylindrical sputter magnetron as metal vapor supply for electron cyclotron resonance ion sources

Energy Technology Data Exchange (ETDEWEB)

Weichsel, T., E-mail: tim.weichsel@fep.fraunhofer.de; Hartung, U.; Kopte, T. [Fraunhofer Institute for Electron Beam and Plasma Technology, 01277 Dresden (Germany); Zschornack, G. [Institute of Solid State Physics, Dresden University of Technology, 01062 Dresden, Germany and Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Ion Beam Physics and Materials Research, Dresden (Germany); Kreller, M.; Silze, A. [DREEBIT GmbH, 01900 Grossroehrsdorf (Germany)

2014-05-15

An inverted cylindrical sputter magnetron device has been developed. The magnetron is acting as a metal vapor supply for an electron cyclotron resonance (ECR) ion source. FEM simulation of magnetic flux density was used to ensure that there is no critical interaction between both magnetic fields of magnetron and ECR ion source. Spatially resolved double Langmuir probe and optical emission spectroscopy measurements show an increase in electron density by one order of magnitude from 1 × 10{sup 10} cm{sup −3} to 1 × 10{sup 11} cm{sup −3}, when the magnetron plasma is exposed to the magnetic mirror field of the ECR ion source. Electron density enhancement is also indicated by magnetron plasma emission photography with a CCD camera. Furthermore, photographs visualize the formation of a localized loss-cone - area, when the magnetron is operated at magnetic mirror field conditions. The inverted cylindrical magnetron supplies a metal atom load rate of R > 1 × 10{sup 18} atoms/s for aluminum, which meets the demand for the production of a milliampere Al{sup +} ion beam.

Vapor pressures and vapor compositions in equilibrium with hypostoichiometric plutonium dioxide at high temperatures

International Nuclear Information System (INIS)

Green, D.W.; Fink, J.K.; Leibowitz, L.

1982-01-01

Vapor pressures and vapor compositions have been calculated for 1500 less than or equal to T less than or equal to 4000 0 K. Thermodynamic functions for the condensed phase and for each of the gaseous species were combined with an oxygen-potential model extended into the liquid region to obtain the partial pressures of O 2 , O, Pu, PuO and PuO 2 . The calculated oxygen pressures increase very rapidly as stoichiometry is approached. At least part of this increase is a consequence of the exclusion of Pu 6 + from the oxygen-potential model. No reliable method was found to estimate the importance of this ion. As a result of large oxygen potentials at high temperatures, extremely high total pressures that produced unreasonably high vapor densities were calculated. The highest temperature was therefore limited to 400 K, and the range of oxygen-to-metal ratios was limited to 1.994 to 1.70. These calculations show that vapor in equilibrium with hypostoichiometric plutonium dioxide is poorly approximated as PuO 2 for most of the temperture and composition range of interest. The vapor is much more oxygen-rich than the condensed phase. Implications for the (U,Pu)O/sub 2-x/ system are discussed

Metal organic vapor phase epitaxy growth of (Al)GaN heterostructures on SiC/Si(111) templates synthesized by topochemical method of atoms substitution

DEFF Research Database (Denmark)

Rozhavskaya, Mariia M.; Kukushkin, Sergey A.; Osipov, Andrey V.

2017-01-01

We report a novel approach for metal organic vapor phase epitaxy of (Al)GaN heterostructures on Si substrates. An approximately 90–100 nm thick SiC buffer layer is synthesized using the reaction between Si substrate and CO gas. Highresolution transmission electron microscopy reveals sharp...

Noble metal (NM) behavior during simulated HLLW vitrification in induction melter with cold crucible

International Nuclear Information System (INIS)

Demin, A.V.; Matyunin, Y.I.; Fedorova, M.I.

1995-01-01

The investigation of noble metal (Ru, Rh, Pd) properties in, glass melts are connected with their specific behaviors during HLLW vitrification. Ruthenium, rhodium and palladium volatilities and heterogeneous platinoid phases forming on melts are investigated in reasonable details conformably to Joule's heating ceramic melters. The vitrification conditions in melters with induction heating of melts are differ from the vitrification ones in ceramic melters on some numbers of parameters (the availability of significant temperature gradients and convection flows in melts, short time of molten mass updating in melter and probability of definite interaction between high-frequency field and melt inhomogeneities). The results of simulated HLLW solidification modelling of the vitrification process in induction melter with cold crucible to produce phosphate and boron-silicate materials are presented. The properties of received glasses and behavior of platinoids are shown to have analogies and distinctions in comparison with compounds, synthesized in ceramic melter. The structures of dispersed particles of NM heterogeneous phases forming in glass melts prepared in induction melter with cold crucible are identified. The results of investigations show, that the marked distinctions between two processes can influence (in definite degree) as on property of synthesized materials, as on behavior of platinoid during vitrifications

Vacuum spark breakdown model based on exploding metal wire phenomena

International Nuclear Information System (INIS)

Haaland, J.

1984-06-01

Spark source mass spectra (SSMS) indicates that ions are extracted from an expanding and decaying plasma. The intensity distribution shows no dependance on vaporization properties of individual elements which indicates explosive vapour formation. This seems further to be a requirement for bridging a vacuum gap. A model including plasma ejection from a superheated anode spot by a process similar to that of an exploding metal wire is proposed. The appearance of hot plasma points in low inductance vacuum sparks can then be explained as exploding micro particles ejected from a final central anode spot. The phenomenological model is compared with available experimental results from literature, but no extensive quantification is attempted

Chemical vapor deposition of yttria stabilized zirconia in porous substrates

International Nuclear Information System (INIS)

Carolan, M.F.; Michaels, J.N.

1987-01-01

Electrochemical vapor deposition (EVD) of yttria stabilized zirconia (YSZ) is the preferred route to the production of thin films of YSZ on porous substrates. This process has been used in the construction of both fuel cells and steam electrolyzers. A critical aspect of the EVD process is an initial chemical vapor deposition phase in which the pores of a porous substrate are plugged by YSZ. In this process, water vapor and a mixture of gaseous zirconium chloride and yttrium chloride diffuse into the porous substrate from opposite sides and react to form YSZ and HCl ga. During the second stage of the process a continuous dense film of electrolyte is formed by a tarnishing-type process. Experimentally it is observed that the pores plug within a few pore diameters of the metal chloride face of the substrate. A kinetic rate expression that is first order in metal chloride but zero order in water is best able to explain this phenomenon. With this rate expression, the pores always plug near the metal chloride face. The model predicts less pore narrowing to occur as the ratio of the reaction rate to the diffusion rate of the metal chloride is increased. A kinetic rate expression that is first order in both water and metal chloride predicts that the pores plug much deeper in the substrate

Theoretical and Experimental Analysis of an Induction Planar Actuator with Different Secondaries—A Planar Driver Application for Metallic Surface Inspection

Directory of Open Access Journals (Sweden)

Felipe Treviso

2016-03-01

Full Text Available This paper presents a study on an induction planar actuator concept. The device uses the same principles as a linear induction motor in which the interaction between a travelling magnetic field and a conducting surface produces eddy currents that leads to the generation of a thrust force and can result in movement over a metallic surface. This can benefit the inspection of metallic surfaces based on the driving platform provided by the induction planar actuator. Equations of the magnetic and electric fields are presented and, by means of these equations, the forces involved were calculated. The behaviour of thrust and normal forces was analysed through the equations and by numerical models, and compared with the results obtained by measurements on a device prototype built in the laboratory as part of the study. With relation to the surface under inspection that forms the secondary, three cases were analysed: (1 a double-layered secondary formed by aluminium and ferromagnetic slabs; (2 a single aluminium layer and (3 a single ferromagnetic layer. Theoretical and measured values of thrust and normal forces showed good correlation.

Infrared transmission study of lanthanide fullerides SmxC60 prepared by metal vapor synthesis

International Nuclear Information System (INIS)

Zhao, W.; Simmons, W.B. Jr.; Sweany, R.L.

1997-01-01

Lanthanide fulleride Sm x C 60 films were prepared by metal vapor synthesis and the valence state of the C 60 cage in the films was investigated by infrared transmission spectroscopy. Three films with different doping contents of Sm showed red-shift frequencies of F 1u (4) at 1347, 1362 and 1392 (1411) cm -1 , respectively, indicating that the major phase with corresponding valence state n∼-5, -3 and -1 might exist in the films. The other major additional feature of activated pentagonal pinch mode A g (2) was observed at 1445 or 1448 cm -1 in the films, which suggested that the Sm atoms might bond to the five-membered ring of the C 60 cage and ferrocene-like Sm x C 60 complexes might be formed. (orig.)

Coplanar UHF RFID tag antenna with U-shaped inductively coupled feed for metallic applications.

Directory of Open Access Journals (Sweden)

Karrar Naji Salman

Full Text Available In this paper, we present a novel compact, coplanar, tag antenna design for metallic objects. Electrically small antenna has designed for a UHF RFID (860-960 MHz based on a proximity-coupled feed through. Furthermore, two symmetrical Via-loaded coplanar grounds fed by a U-shaped inductively coupled feed through an embedded transmission line. This configuration results in an antenna with dimensions of 31 × 19.5 × 3.065 mm3 at 915 MHz, and the total gain for the antenna is 0.12 dBi. The Via-loaded coplanar and U-shaped inductively coupled feeds allow the antenna to provide flexible tuning in terms of antenna impedance. In addition, a figure of merit is applied for the proposed tag antenna, and the results are presented. The read range is measured to be 4.2 m, which is very close to simulated values. This antenna measurement shows very good agreement with simulations.

Mass-spectrometric study of ion clustering in alkali-metal hydroxide vapor: cluster-ion energy and structural characteristics

International Nuclear Information System (INIS)

Kudin, L.S.; Butman, M.F.; Krasnov, K.S.

1986-01-01

Various positive and negative ions have been recorded in the equilibrium vapors from alkali-metal hydroxides: M/sup +/-/, OH - , O - , MO - , MOH - , and X/sup +/-/ (MOH)/sub n/, where X = M/sup +/-/, OH - , n = 1-6. The equilibrium constants have been measured for X/sup +/-/(MOH)/sub n/ = x/sup +/-/ + nMOH(k), n = 1-3, and the enthalpies of reaction have been determined, from which the enthalpies of formation and dissociation energies of X/sup +/-/ (MOH)/sub n/ have been calculated. The relative stabilities of the ions in the series from Na to Cs are examined

High-voltage vertical GaN Schottky diode enabled by low-carbon metal-organic chemical vapor deposition growth

Science.gov (United States)

Cao, Y.; Chu, R.; Li, R.; Chen, M.; Chang, R.; Hughes, B.

2016-02-01

Vertical GaN Schottky barrier diode (SBD) structures were grown by metal-organic chemical vapor deposition on free-standing GaN substrates. The carbon doping effect on SBD performance was studied by adjusting the growth conditions and spanning the carbon doping concentration between ≤3 × 1015 cm-3 and 3 × 1019 cm-3. Using the optimized growth conditions that resulted in the lowest carbon incorporation, a vertical GaN SBD with a 6-μm drift layer was fabricated. A low turn-on voltage of 0.77 V with a breakdown voltage over 800 V was obtained from the device.

UHF-plasma torch emission spectrometry for cadmium, lead and zinc by vaporization introduction

International Nuclear Information System (INIS)

Nakashima, Ryozo

1978-01-01

As the introduction technique of aerosol into the plasma torch, vaporization introduction of metals was studied. An aliquot of metal nitrates was pipetted in a graphite crucible and dried with a vacuum pump. The dried sample was heated in a high-frequency induction furnace under inert gas carrier such as argon or nitrogen (reduction introduction). Chlorination introduction with hydrogen chloride was also studied. High-purity grade of argon, nitrogen and hydrogen chloride was used as carrier. Intensities were based on the peak area of intensity-time curves at 228.8 nm (cadmium), 405.8 nm (lead), and 213.9 nm (zinc). In the reduction introduction, the minimum temperatures to attain a constant peak area, which means a complete vaporization were 700 0 C (cadmium), 1500 0 C (lead), and 1100 0 C (zinc), respectively. In the chlorination, this temperature was 500 0 C (cadmium), 700 0 C (lead), and 300 0 C (zinc) respectively. For two introduction techniques, the latter was more sensitive than the former for cadmium and zinc, while the former was more sensitive for lead. The optimum temperature, detection limits, and the coefficients of variance calculated from the measurements of 1.0 μg of metals were as follows: Cadmium: chlorination at 850 0 C, D.L. 5ng, C.V. 10%. Lead: reduction at 1600 0 C, D.L. 10ng, C.V. 15%. Zinc: chlorination at 850 0 C, D.L. 5ng, C.V. 9%. Linear calibration lines having 45 0 slope at log-log plots, were obtained over the range from 0.05 to 6 μg for cadmium and zinc, 0.06 to 6 μg for lead on the conditions above. These techniques were also applied for analyses of biological materials for three metals without prior separations. Although the sensitivity of the chlorination introduction technique for lead was rather poor compared with that of reduction technique, the chlorination technique was applied to minimize the introduction of coexisting materials such as alkali and alkaline earth metals. The analytical results agreed reasonably with the

Development of halide copper vapor laser (the characteristics of using Cul)

International Nuclear Information System (INIS)

Oouti, Kazumi; Wada, Yukio; Sasao, Nobuyuki

1990-01-01

We are developing halide copper vapor laser that is high efficiency and high reputation rate visible laser. Halide copper vapor laser uses halide copper of copper vapor source. It melts low temperature in comporison with metal copper, because laser tube structure is very simple and it can operate easy. This time, we experiment to use Cul for copper vapor source. We resulted maximum output energy 17.8 (W) and maximum efficiency 0.78 (%) when operate condition was reputation rate 30 (kHz), gas pressure 90 (Torr), charging voltage 13 (kV). (author)

Phenomenological modeling of the drying of a thin cloth with a rotating cylinder heated by electromagnetic induction; Modelisation phenomenologique du sechage d'une nappe mince avec un cylindre rotatoire chauffe par induction electromagnetique

Energy Technology Data Exchange (ETDEWEB)

Perez, S. [Universidad de Carabobo, Facultad de Ingenieria, Valencia (Venezuela); Therien, N.; Broadbent, A.D. [Sherbrooke Univ., Faculte de Genie, Quebec (Canada)

2001-07-01

A phenomenological model of the evolution of the humidity and temperature during the drying of a thin fiber cloth in contact with a metal surface heated by electric induction is presented. The model calculates also the temperature inside the cylinder with respect to its position. Differential mass and energy statuses are established and the concept of substantial derivative is used to bind the state variables with respect to the time and position. The conduction, convection, radiant heat transfer, thermal induction, and energy transfer due to water vaporization are explicitly considered. The model takes into consideration the disturbances due to the variations of the humidity of the cloth at the input of the process. It calculates the response of the process in front of these disturbances and in front of the rotation speed of the cylinder and the electric power supplied to the system. Multiple experiments performed on a bench test have permitted to characterize the response of the drying process (temperature of the cylinder, humidity and temperature of the cloth) under different combinations of conditions. (J.S.)

Technology and equipment based on induction melters with ''cold'' crucible for reprocessing active metal waste

International Nuclear Information System (INIS)

Pastushkov, V.G.; Molchanov, A.V.; Serebryakov, V.P.; Smelova, T.V.; Shestoperov, I.N.

2000-01-01

The operation and, particularly, the decommissioning of NPPs and radiochemical plants result in substantial arisings of radioactive metal waste (RAMW) having different activity levels (from 5 x 10 -4 to ∼ 40 Ci/kg). The paper reviews the specific features of the technology and equipment used to melt RAMW in electric arc and induction furnaces with ceramic or 'cold' crucibles. The experimentally determined and calculated data are given on the level to which RAMW is decontaminated from the main radionuclides as well as on the distribution of the latter in the products of melting (ingot, slag, gaseous phase). Special attention is focused on the process and the facility for the induction-slag melting of RAMW in furnaces equipped with 'cold' crucibles. The work is described that is under way at SSC RF VNIINM to master the technology of melting simulated high activity level Zr-alloy and stainless steel waste. (authors)

Development of metal oxide gas sensors for very low concentration (ppb) of BTEX vapors

Science.gov (United States)

Favard, A.; Aguir, K.; Contaret, T.; Caris, L.; Bendahan, M.

2017-12-01

The control and analysis of air quality have become a major preoccupation of the last twenty years. In 2008, the European Union has introduced a Directive (2008/50/EC) to impose measurement obligations and thresholds to not exceed for some pollutants, including BTEX gases, in view of their adverse effects on the health. In this paper, we show the ability to detect very low concentrations of BTEX using a gas microsensor based on metal oxide thin-film. A test bench able to generate very low vapors concentrations has been achieved and fully automated. Thin metal oxides layers have been realized by reactive magnetron sputtering. The sensitive layers are functionalized with gold nanoparticles by thermal evaporation technique. Our sensors have been tested on a wide range of concentrations of BTEX (5 - 500 ppb) and have been able to detect concentrations of a few ppb for operating temperatures below 593 K. These results are very promising for detection of very low BTEX concentration for indoor as well as outdoor application. We showed that the addition of gold nanoparticles on the sensitive layers decreases the sensors operating temperature and increases the response to BTEX gas. The best results are obtained with a sensitive layer based on ZnO.

Low temperature vapor phase digestion of graphite

Energy Technology Data Exchange (ETDEWEB)

Pierce, Robert A.

2017-04-18

A method for digestion and gasification of graphite for removal from an underlying surface is described. The method can be utilized to remove graphite remnants of a formation process from the formed metal piece in a cleaning process. The method can be particularly beneficial in cleaning castings formed with graphite molding materials. The method can utilize vaporous nitric acid (HNO.sub.3) or vaporous HNO.sub.3 with air/oxygen to digest the graphite at conditions that can avoid damage to the underlying surface.

Electrothermal vaporization inductively coupled plasma mass spectrometry for the determination of trace amount of lanthanides and yttrium in soil with polytetrafluroethylene emulsion as a chemical modifier

International Nuclear Information System (INIS)

He Man; Hu, Bin; Jiang Zucheng

2005-01-01

A method of electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) for the determination of trace lanthanides and yttrium in soil samples with a polytetrafluorethylene (PTFE) emulsion as chemical modifier to promote the vaporization of the analytes from the graphite furnace was developed in this paper. The analytical characteristics, spectral interference and matrix effect of the analytical method were evaluated and critically compared with those of pneumatic nebulization inductively coupled plasma mass spectrometry (PN-ICP-MS). Under the optimized operation conditions, the relative detection limits of lanthanides (La-Lu) and yttrium for ETV-ICP-MS and PN-ICP-MS were 0.4-20 ng l -1 and 1.0-21 ng l -1 , respectively, the absolute detection limits for ETV-ICP-MS were 4-200 fg, which were improved by 1-2 orders of magnitude compared with PN-ICP-MS. While the analytical precision of ETV-ICP-MS is worse than that of PN-ICP-MS, with the R.S.D.s (%) of 4.1-10% for the former and 2.9-7.8% for the latter. Regarding to the matrix effect, both conventional method and stepwise dilution method were employed to observe the effect of matrix and the very similar results were obtained. It was found that the highest tolerance concentration of the matrix is 1000 mg l -1 and 800 mg l -1 for ETV-ICP-MS and PN-ICP-MS, respectively. To assess the accuracy, the proposed method was applied to the determination of trace lanthanides and yttrium in three different soil standard reference materials and one soil sample, and the determined values are in good agreement with the certified values or reference values

Simultaneous electrothermal vaporization and nebulizer sample introduction system for inductively coupled plasma mass spectrometry

International Nuclear Information System (INIS)

Arnquist, Isaac J.; Kreschollek, Thomas E.; Holcombe, James A.

2011-01-01

The novel analytical application of the combination of an inline electrothermal vaporization (ETV) and nebulization source for inductively coupled plasma mass spectrometry (ICP-MS) has been studied. Wet plasma conditions are sustained during ETV introduction by 200 mL/min gas flow through the nebulizer, which is merged with the ETV transport line at the torch. The use of a wet plasma with ETV introduction avoided the need to change power settings and torch positions that normally accompany a change from wet to dry plasma operating conditions. This inline-ETV source is shown to have good detection limits for a variety of elements in both HNO 3 and HCl matrices. Using the inline-ETV source, improved limits of detection (LOD) were obtained for elements typically suppressed by polyatomic interferences using a nebulizer. Specifically, improved LODs for 51 V and 53 Cr suffering from Cl interferences ( 51 ClO + and 53 ClO + respectively) in a 1% HCl matrix were obtained using the inline-ETV source. LODs were improved by factors of 65 and 22 for 51 V and 53 Cr, respectively, using the inline-ETV source compared to a conventional concentric glass nebulizer. For elements without polyatomic interferences, LODs from the inline-ETV were comparable to conventional dry plasma ETV-ICP time-of-flight mass spectrometry results. Lastly, the inline-ETV source offers a simple means of changing from nebulizer introduction to inline-ETV introduction without extinguishing the plasma. This permits, for example, the use of the time-resolved ETV-ICP-MS signals to distinguish between an analyte ion and polyatomic isobar.

Microcomponents manufacturing for precise devices by copper vapor laser

Science.gov (United States)

Gorny, Sergey; Nikonchuk, Michail O.; Polyakov, Igor V.

2001-06-01

This paper presents investigation results of drilling of metal microcomponents by copper vapor laser. The laser consists of master oscillator - spatial filter - amplifier system, electronics switching with digital control of laser pulse repetition rate and quantity of pulses, x-y stage with computer control system. Mass of metal, removed by one laser pulse, is measured and defined by means of diameter and depth of holes. Interaction of next pulses on drilled material is discussed. The difference between light absorption and metal evaporation processes is considered for drilling and cutting. Efficiency of drilling is estimated by ratio of evaporation heat and used laser energy. Maximum efficiency of steel cutting is calculated with experimental data of drilling. Applications of copper vapor laser for manufacturing is illustrated by such microcomponents as pin guide plate for printers, stents for cardio surgery, encoded disks for security systems and multiple slit masks for spectrophotometers.

Composition and Morphology Control of Metal Dichalcogenides via Chemical Vapor Deposition for Photovoltaic and Nanoelectronic Applications

Science.gov (United States)

Samad, Leith L. J.

The body of work reviewed here encompasses a variety of metal dichalcogenides all synthesized using chemical vapor deposition (CVD) for solar and electronics applications. The first reported phase-pure CVD synthesis of iron pyrite thin films is presented with detailed structural and electrochemical analysis. The phase-pure thin film and improved crystal growth on a metallic backing material represents one of the best options for potential solar applications using iron pyrite. Large tin-sulfur-selenide solid solution plates with tunable bandgaps were also synthesized via CVD as single-crystals with a thin film geometry. Solid solution tin-sulfur-selenide plates were demonstrated to be a new material for solar cells with the first observed solar conversion efficiencies up to 3.1%. Finally, a low temperature molybdenum disulfide vertical heterostructure CVD synthesis with layered controlled growth was achieved with preferential growth enabled by Van der Waals epitaxy. Through recognition of additional reaction parameters, a fully regulated CVD synthesis enabled the controlled growth of 1-6 molybdenum disulfide monolayers for nanoelectronic applications. The improvements in synthesis and materials presented here were all enabled by the control afforded by CVD such that advances in phase purity, growth, and composition control of several metal dichalcogenides were achieved. Further work will be able to take full advantage of these advances for future solar and electronics technologies.

Accurate determination of non-metallic impurities in high purity tetramethylammonium hydroxide using inductively coupled plasma tandem mass spectrometry

Science.gov (United States)

Fu, Liang; Xie, Hualin; Shi, Shuyun; Chen, Xiaoqing

2018-06-01

The content of non-metallic impurities in high-purity tetramethylammonium hydroxide (HPTMAH) aqueous solution has an important influence on the yield, electrical properties and reliability of the integrated circuit during the process of chip etching and cleaning. Therefore, an efficient analytical method to directly quantify the content of non-metallic impurities in HPTMAH aqueous solutions is necessary. The present study was aimed to develop a novel method that can accurately determine seven non-metallic impurities (B, Si, P, S, Cl, As, and Se) in an aqueous solution of HPTMAH by inductively coupled plasma tandem mass spectrometry (ICP-MS/MS). The samples were measured using a direct injection method. In the MS/MS mode, oxygen and hydrogen were used as reaction gases in the octopole reaction system (ORS) to eliminate mass spectral interferences during the analytical process. The detection limits of B, Si, P, S, Cl, As, and Se were 0.31, 0.48, 0.051, 0.27, 3.10, 0.008, and 0.005 μg L-1, respectively. The samples were analyzed by the developed method and the sector field inductively coupled plasma mass spectrometry (SF-ICP-MS) was used for contrastive analysis. The values of these seven elements measured using ICP-MS/MS were consistent with those measured by SF-ICP-MS. The proposed method can be utilized to analyze non-metallic impurities in HPTMAH aqueous solution. Table S2 Multiple potential interferences on the analytes. Table S3 Parameters of calibration curve and the detection limit (DL). Table S4 Results obtained for 25% concentration high-purity grade TMAH aqueous solution samples (μg L-1, mean ± standard deviation, n = 10).

High levels of heavy metal accumulation in dental calculus of smokers: a pilot inductively coupled plasma mass spectrometry study.

Science.gov (United States)

Yaprak, E; Yolcubal, I; Sinanoğlu, A; Doğrul-Demiray, A; Guzeldemir-Akcakanat, E; Marakoğlu, I

2017-02-01

Various trace elements, including toxic heavy metals, may exist in dental calculus. However, the effect of environmental factors on heavy metal composition of dental calculus is unknown. Smoking is a major environmental source for chronic toxic heavy metal exposition. The aim of this study is to compare toxic heavy metal accumulation levels in supragingival dental calculus of smokers and non-smokers. A total of 29 supragingival dental calculus samples were obtained from non-smoker (n = 14) and smoker (n = 15) individuals. Subjects with a probability of occupational exposure were excluded from the study. Samples were analyzed by inductively coupled plasma mass spectrometry in terms of 26 metals and metalloids, including toxic heavy metals. Toxic heavy metals, arsenic (p 0.05). Within the limitations of this study, it can be concluded that the elementary composition of dental calculus may be affected by environmental factors such as tobacco smoke. Therefore, dental calculus may be utilized as a non-invasive diagnostic biological material for monitoring chronic oral heavy metal exposition. However, further studies are required to evaluate its diagnostic potential. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Dynamically Babinet-invertible metasurface: a capacitive-inductive reconfigurable filter for terahertz waves using vanadium-dioxide metal-insulator transition

Science.gov (United States)

Urade, Yoshiro; Nakata, Yosuke; Okimura, Kunio; Nakanishi, Toshihiro; Miyamaru, Fumiaki; Takeda, Mitsuo W.; Kitano, Masao

2016-03-01

This paper proposes a reconfigurable planar metamaterial that can be switched between capacitive and inductive responses using local changes in the electrical conductivity of its constituent material. The proposed device is based on Babinet's principle and exploits the singular electromagnetic responses of metallic checkerboard structures, which are dependent on the local electrical conductivity. Utilizing the heating-induced metal-insulator transition of vanadium dioxide ($\\mathrm{VO}_2$), the proposed metamaterial is designed to compensate for the effect of the substrate and is experimentally characterized in the terahertz regime. This reconfigurable metamaterial can be utilized as a switchable filter and as a switchable phase shifter for terahertz waves.

Mobile vapor recovery and vapor scavenging unit

International Nuclear Information System (INIS)

Stokes, C.A.; Steppe, D.E.

1991-01-01

This patent describes a mobile anti- pollution apparatus, for the recovery of hydrocarbon emissions. It comprises a mobile platform upon which is mounted a vapor recovery unit for recovering vapors including light hydrocarbons, the vapor recovery unit having an inlet and an outlet end, the inlet end adapted for coupling to an external source of hydrocarbon vapor emissions to recover a portion of the vapors including light hydrocarbons emitted therefrom, and the outlet end adapted for connection to a means for conveying unrecovered vapors to a vapor scavenging unit, the vapor scavenging unit comprising an internal combustion engine adapted for utilizing light hydrocarbon in the unrecovered vapors exiting from the vapor recovery unit as supplemental fuel

Chemical vapor deposited fiber coatings and chemical vapor infiltrated ceramic matrix composites

Energy Technology Data Exchange (ETDEWEB)

Kmetz, M.A.

1992-01-01

Conventional Chemical Vapor Deposition (CVD) and Organometallic Chemical Vapor Deposition (MOCVD) were employed to deposit a series of interfacial coatings on SiC and carbon yarn. Molybdenum, tungsten and chromium hexacarbonyls were utilized as precursors in a low temperature (350[degrees]C) MOCVD process to coat SiC yarn with Mo, W and Cr oxycarbides. Annealing studies performed on the MoOC and WOC coated SiC yarns in N[sub 2] to 1,000[degrees]C establish that further decomposition of the oxycarbides occurred, culminating in the formation of the metals. These metals were then found to react with Si to form Mo and W disilicide coatings. In the Cr system, heating in N[sub 2] above 800[degrees]C resulted in the formation of a mixture of carbides and oxides. Convention CVD was also employed to coat SiC and carbon yarn with C, Bn and a new interface designated BC (a carbon-boron alloy). The coated tows were then infiltrated with SiC, TiO[sub 2], SiO[sub 2] and B[sub 4]C by a chemical vapor infiltration process. The B-C coatings were found to provide advantageous interfacial properties over carbon and BN coatings in several different composite systems. The effectiveness of these different coatings to act as a chemically inert barrier layer and their relationship to the degree of interfacial debonding on the mechanical properties of the composites were examined. The effects of thermal stability and strength of the coated fibers and composites were also determined for several difference atmospheres. In addition, a new method for determining the tensile strength of the as-received and coated yarns was also developed. The coated fibers and composites were further characterized by AES, SEM, XPS, IR and X-ray diffraction analysis.

Slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry for steelmaking flue dust analysis

Science.gov (United States)

Coedo, A. G.; Dorado, T.; Padilla, I.; Maibusch, R.; Kuss, H.-M.

2000-02-01

A commercial atomic absorption graphite furnace (AAGF), with a self-made adapter and valve system, was used as a slurry sampling cell for electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS). The system was applied to the determination of As, Sn, Sb, Se, Te, Bi, Cd, V, Ti and Mo in steelmaking flue dusts. Experimental conditions with respect to ETV and ICP-MS operating parameters were optimized. Compared to aqueous solutions, slurry samples were found to present better analyte transport. Microgram amounts of Rh were used to reduce the difference in analyte response in sensitivity for aqueous solutions of the tested analytes. No such increasing effect was observed for slurry samples and aqueous standards. An added quantity of Rh acting as modifier/carrier resulted in an increase for the same analytes in matrix-slurry solutions, even the addition of an extra Rh quantity has resulted in a decrease in the signals. The effect of Triton X-100 (used as a dispersant agent) on analyte intensity and precision was also studied. External calibration from aqueous standards spiked with 100 μg ml -1 Rh was performed to quantified 0.010 g/100 ml slurry samples. Results are presented for a certified reference electrical arc furnace flue dust (EAF): CRM-876-1 (Bureau of Analysis Samples Ltd., Cleveland, UK), a reference sample of coke ashes X-3705 (from AG der Dillinger Hüttenwerke, Germany), and a representative sample of EAF flue dust from a Spanish steelmaking company (CENIM-1). For the two reference materials an acceptable agreement with certificate values was achieved, and the results for the CENIM sample matched with those obtained from conventional nebulization solution.

Acoustic imaging of vapor bubbles through optically non-transparent media

International Nuclear Information System (INIS)

Kolbe, W.F.; Turko, B.T.; Leskovar, B.

1983-10-01

A preliminary investigation of the feasibility of acoustic imaging of vapor bubbles through optically nontransparent media is described. Measurements are reported showing the echo signals produced by air filled glass spheres of various sizes positioned in an aqueous medium as well as signals produced by actual vapor bubbles within a water filled steel pipe. In addition, the influence of the metallic wall thickness and material on the amplitude of the echo signals is investigated. Finally several examples are given of the imaging of spherical bubbles within metallic pipes using a simulated array of acoustic transducers mounted circumferentially around the pipe. The measurement procedures and a description of the measuring system are also given

Induction of heat shock proteins (hsp70) in the zebra mussel (Dreissena polymorpha) following exposure to platinum group metals (platinum, palladium and rhodium): Comparison with lead and cadmium exposures

Energy Technology Data Exchange (ETDEWEB)

Singer, Christoph [Zoologisches Institut I-Oekologie, Universitaet Karlsruhe, Geb. 07.01, Kornblumenstrasse 13, D-76131 Karlsruhe (Germany); Zimmermann, Sonja [Zoologisches Institut I-Oekologie, Universitaet Karlsruhe, Geb. 07.01, Kornblumenstrasse 13, D-76131 Karlsruhe (Germany); Sures, Bernd [Zoologisches Institut I-Oekologie, Universitaet Karlsruhe, Geb. 07.01, Kornblumenstrasse 13, D-76131 Karlsruhe (Germany)]. E-mail: dc11@rz.uni-karlsruhe.de

2005-10-05

An increasing number of papers concentrate on the availability and uptake of platinum group elements (PGE) by different organisms. These metals are discharged into the environment from different anthropogenic sources, such as automobile catalytic converters, hospitals and other medical institutions. As the effects of these precious metals on organisms remain unclear, the induction of heat shock proteins (hsp70) in zebra mussels (Dreissena polymorpha) following exposure to soluble salts of platinum, palladium and rhodium was compared with the hsp70 induction in mussels following exposure to cadmium and lead. Mussels were sampled weekly during a period of 10 weeks and analyzed for their metal concentration and their hsp70 level. Highest metal uptake was found for Cd, followed by Pt, Pb and Pd. Rh demonstrated the lowest uptake rate. A clear time-dependent increase of hsp70 levels occurred in all exposed mussels. Concentrations of hsp70 started to rise between days 18 and 25, except for the Pt-exposed group, where the initial increase was between days 25 and 32. All groups reached maximal hsp70 concentrations at day 39. Subsequently, hsp70 levels decreased to initial levels for the remaining exposure period. Threshold metal levels for the hsp70 induction varied among the metals and increased in the order: Rh < Pd {<=} Pb < Pt < Cd. Highest hsp70 values were found for mussels exposed to Pd, with a 25-fold higher level than in the controls, followed by Pt- and Rh-exposed mussels, which showed a 19-fold increase. The hsp70 levels of the mussels exposed to Cd and Pb were much lower, showing 6- and 12-fold higher values than the control, respectively. The clear induction of hsp70 due to exposure to Pt, Pd and Rh gives evidence for strong cellular effects of these metals, especially, when compared with lead and cadmium. Among the metals tested, Pd seems to have the highest potential as inducer for hsp70 production due to its low threshold level in combination with the

Induction of heat shock proteins (hsp70) in the zebra mussel (Dreissena polymorpha) following exposure to platinum group metals (platinum, palladium and rhodium): Comparison with lead and cadmium exposures

International Nuclear Information System (INIS)

Singer, Christoph; Zimmermann, Sonja; Sures, Bernd

2005-01-01

An increasing number of papers concentrate on the availability and uptake of platinum group elements (PGE) by different organisms. These metals are discharged into the environment from different anthropogenic sources, such as automobile catalytic converters, hospitals and other medical institutions. As the effects of these precious metals on organisms remain unclear, the induction of heat shock proteins (hsp70) in zebra mussels (Dreissena polymorpha) following exposure to soluble salts of platinum, palladium and rhodium was compared with the hsp70 induction in mussels following exposure to cadmium and lead. Mussels were sampled weekly during a period of 10 weeks and analyzed for their metal concentration and their hsp70 level. Highest metal uptake was found for Cd, followed by Pt, Pb and Pd. Rh demonstrated the lowest uptake rate. A clear time-dependent increase of hsp70 levels occurred in all exposed mussels. Concentrations of hsp70 started to rise between days 18 and 25, except for the Pt-exposed group, where the initial increase was between days 25 and 32. All groups reached maximal hsp70 concentrations at day 39. Subsequently, hsp70 levels decreased to initial levels for the remaining exposure period. Threshold metal levels for the hsp70 induction varied among the metals and increased in the order: Rh < Pd ≤ Pb < Pt < Cd. Highest hsp70 values were found for mussels exposed to Pd, with a 25-fold higher level than in the controls, followed by Pt- and Rh-exposed mussels, which showed a 19-fold increase. The hsp70 levels of the mussels exposed to Cd and Pb were much lower, showing 6- and 12-fold higher values than the control, respectively. The clear induction of hsp70 due to exposure to Pt, Pd and Rh gives evidence for strong cellular effects of these metals, especially, when compared with lead and cadmium. Among the metals tested, Pd seems to have the highest potential as inducer for hsp70 production due to its low threshold level in combination with the

Inductive coupling between overhead power lines and nearby metallic pipelines. A neural network approach

Directory of Open Access Journals (Sweden)

Levente Czumbil

2015-12-01

Full Text Available The current paper presents an artificial intelligence based technique applied in the investigation of electromagnetic interference problems between high voltage power lines (HVPL and nearby underground metallic pipelines (MP. An artificial neural network (NN solution has been implemented by the authors to evaluate the inductive coupling between HVPL and MP for different constructive geometries of an electromagnetic interference problem considering a multi-layer soil structure. Obtained results are compared to solutions provided by a finite element method (FEM based analysis and considered as reference. The advantage of the proposed method yields in a simplified computation model compared to FEM, and implicitly a lower computational time.

A Local Propagation for Vapor Explosions

International Nuclear Information System (INIS)

Ochiai, M.; Bankoff, S.G.

1976-01-01

explosion can be made. Both theories postulate that spontaneous nucleation is a necessary requirement for vapor explosions. In the case of Freon-oil, which can be considered to be a 'well-wetted' system, this implies homogeneous nucleation. For metal-water systems, however, vapor-free heterogeneous nucleation may take place, in view of the unique surface properties of water. Indeed, for aqueous systems it is difficult to suppress very small pre-existing surface nuclei. The practical effect, however, is the same in that nucleation may occur in metal-water systems at liquid-liquid interfacial temperatures somewhat below the homogeneous nucleation temperature of water, but with comparable time scales and vapor pressures. Another important requirement common to both the splash and capture theories, as well as the Freon-oil data, is the necessity for film boiling to occur when the two liquids are initially mixed. This requirement is not satisfied by the sodium-UO 2 system, based on the Henry film bailing correlation. Rapid breakup therefore occurs as the two liquids are mixed, preventing a highly energetic interaction. Our current assessment, therefore, is that a sodium-UO 2 vapor explosion in a reactor environment is extremely unlikely

Coupling scales for modelling heavy metal vaporization from municipal solid waste incineration in a fluid bed by CFD.

Science.gov (United States)

Soria, José; Gauthier, Daniel; Flamant, Gilles; Rodriguez, Rosa; Mazza, Germán

2015-09-01

Municipal Solid Waste Incineration (MSWI) in fluidized bed is a very interesting technology mainly due to high combustion efficiency, great flexibility for treating several types of waste fuels and reduction in pollutants emitted with the flue gas. However, there is a great concern with respect to the fate of heavy metals (HM) contained in MSW and their environmental impact. In this study, a coupled two-scale CFD model was developed for MSWI in a bubbling fluidized bed. It presents an original scheme that combines a single particle model and a global fluidized bed model in order to represent the HM vaporization during MSW combustion. Two of the most representative HM (Cd and Pb) with bed temperatures ranging between 923 and 1073K have been considered. This new approach uses ANSYS FLUENT 14.0 as the modelling platform for the simulations along with a complete set of self-developed user-defined functions (UDFs). The simulation results are compared to the experimental data obtained previously by the research group in a lab-scale fluid bed incinerator. The comparison indicates that the proposed CFD model predicts well the evolution of the HM release for the bed temperatures analyzed. It shows that both bed temperature and bed dynamics have influence on the HM vaporization rate. It can be concluded that CFD is a rigorous tool that provides valuable information about HM vaporization and that the original two-scale simulation scheme adopted allows to better represent the actual particle behavior in a fluid bed incinerator. Copyright © 2015 Elsevier Ltd. All rights reserved.

Consolidation of simulated nuclear metallic waste by vacuum coreless induction melting

International Nuclear Information System (INIS)

Montgomery, D.R.

1984-10-01

Vacuum coreless induction melting with bottom pouring has exceeded expectations for simplicity, reliability, and versatility when melting the zirconium and iron eutectic alloy. The melting tests have established that: the eutectic mixture of oxidized Zircaloy 4 hulls mixed with Type 316 stainless steel hulls can be melted at 41 kg/h at 40 kW with a power consumption of 1.03 kWh/kg and a melting temperature of 1260 0 C; the life of a graphite crucible can be expected to be longer by a factor of 4 than was previously projected; the bottom-pour water-cooled copper freeze plug was 100% reliable; a 24-in.-tall stainless steel canister with 1/4-in.-thick walls (6-in. inside diameter) was satisfactory in every respect; an ingot formed from 4 consecutive heats poured into a stainless steel canister appeared to be approx. 99% dense after sectioning; preplaced scrap in the canister can be encapsulated with molten metal to about 99% density; large pieces of Zircaloy 4 and stainless steel scrap can be melted, but have differing melting parameters; the pouring nozzle requires further development to prevent solidified drops from forming at the hole exit after a pour. It is recommended that a large-scale cold mock-up facility be established to refine and test a full-scale vacuum coreless induction melting system. Other options might include further scaled-down experiments to test other alloys and crucible materials under different atmospheric conditions (i.e., air melting). 1 reference, 18 figures, 1 table

Heavy metals in aromatic spices by inductively coupled plasma-mass spectrometry.

Science.gov (United States)

Bua, Daniel Giuseppe; Annuario, Giovanni; Albergamo, Ambrogina; Cicero, Nicola; Dugo, Giacomo

2016-09-01

Objective of this study was to determine the content of Cd, Hg, As and Pb in common spices traded in the Italian market, using inductively coupled plasma-mass spectrometry (ICP-MS). The results were compared with the maximum limits established by the national Legislative Decree (LD) no. 107 implementing the Council Directive 88/388/EEC and by international organisations, such as Food and Agriculture Organization (FAO) and World Health Organization (WHO). Food safety for spices was assessed considering the tolerable weekly intake (TWI) and the provisional tolerable weekly intake (PTWI), respectively, for Cd and Hg and the 95% lower confidence limit of the benchmark dose of 1% extra risk (BMDL01) for As and Pb. Investigated elements in all samples were within the maximum limits as set by the national and international normative institutions. Nevertheless, the heavy metal content of some spices exceeded the PTWI, TWI and BMDL01, which needs attention when considering consumer's health.

Epitaxial Oxide Thin Films Grown by Solid Source Metal-Organic Chemical Vapor Deposition.

Science.gov (United States)

Lu, Zihong

1995-01-01

The conventional liquid source metal-organic chemical vapor deposition (MOCVD) technique is capable of producing large area, high quality, single crystal semiconductor films. However, the growth of complex oxide films by this method has been hampered by a lack of suitable source materials. While chemists have been actively searching for new source materials, the research work reported here has demonstrated the successful application of solid metal-organic sources (based on tetramethylheptanedionate) to the growth of high quality thin films of binary compound cerium dioxide (CeO_2), and two more complex materials, the ternary compound lithium niobate (LiNbO_3), with two cations, and the quaternary compound strontium barium niobate (SBN), with three cations. The growth of CeO_2 thin films on (1012)Al_2O_3 substrates has been used as a model to study the general growth behavior of oxides. Factors affecting deposition rate, surface morphology, out-of-plane mosaic structure, and film orientation have been carefully investigated. A kinetic model based on gas phase prereaction is proposed to account for the substrate temperature dependence of film orientation found in this system. Atomically smooth, single crystal quality cerium dioxide thin films have been obtained. Superconducting YBCO films sputtered on top of solid source MOCVD grown thin cerium dioxide buffer layers on sapphire have been shown to have physical properties as good as those of YBCO films grown on single crystal MgO substrates. The thin film growth of LiNbO_3 and Sr_{1-x}Ba _{x}Nb_2 O_6 (SBN) was more complex and challenging. Phase purity, transparency, in-plane orientation, and the ferroelectric polarity of LiNbO _3 films grown on sapphire substrates was investigated. The first optical quality, MOCVD grown LiNbO _3 films, having waveguiding losses of less than 2 dB/cm, were prepared. An important aspect of the SBN film growth studies involved finding a suitable single crystal substrate material. Mg

Effect of degree of subcooling on vapor explosion

International Nuclear Information System (INIS)

Xu Zhihong; Yang Yanhua; Li Tianshu

2010-01-01

In order to investigate the mechanism of the vapor explosion, an observable experiment equipment for low-temperature molten materials to be dropped into water was designed. In the experiment, molten material jet was injected into water to experimentally obtain the visualized information. This experiment results show that the degree of subcooling restrains the explosion. In order to validate the result by other aspects, the breakup experiment was conducted. Results show that the degree of water subcooling is important to melt breakup. High temperature of water is easy to increase the vapor generation during molten material falling, which decrease the drag and accelerated the molten material falling. At the same time, more vapor appear around the molten metal decrease the heat transfer amount between water and molten materials. The two experimental results coincide. (authors)

First report of phytochelatins in a mushroom: induction of phytochelatins by metal exposure in Boletus edulis.

Science.gov (United States)

Collin-Hansen, Christian; Pedersen, Sindre A; Andersen, Rolf A; Steinnes, Eiliv

2007-01-01

Some species of macromycetes (mushrooms) consistently are found to contain high concentrations of toxic metals such as cadmium (Cd) and mercury (Hg), and consumption of wild-growing mushrooms is acknowledged as a significant source for Cd and Hg in humans. Yet little is known about the speciation of Cd and Hg in mushroom tissues. Here we present the first evidence of peptides of the phytochelatin family being responsible for binding a large fraction of Cd in caps of the macromycete Boletus edulis exposed to excess metals. Concentrations of Cd, Zn, Cu and Hg, as well as cytosolic Cd-binding capacity (CCBC), glutathione (GSH) and free proline (Pro) were quantified in fruiting bodies of B. edulis differentially exposed to a wide range of metals. Metal distribution among cytosolic compounds were investigated by size exclusion chromatography (SEC), followed by metal determinations with atomic absorption chromatography (AAS) and HR-ICP-MS. Cd-binding compounds in SEC elutates were investigated further by high performance liquid chromatography-mass spectrometry (HPLC-MS). CCBC was >90 times higher in the exposed group relative to the reference group (Mann-Whitney's P < 0.001), whereas concentrations of free Pro were almost identical for the two groups. For the whole study selection, CCBC correlated positively with metal exposure (Spearman's P < 0.001 for all four metals), suggesting dose-dependent induction of Cd-binding compounds by exposure to these metals, possibly as a defense mechanism. The presence of phytochelatins (PCs), a family of cystein-rich oligopeptides, was confirmed in Cd-containing SEC fractions by HPLC-MS. The appearance of more complex PCs was coupled to declining concentrations of GSH. To our knowledge this is the first report demonstrating the presence of PCs in a macromycete.

Metal assessment in sediments from the Guarapiranga Reservoir

International Nuclear Information System (INIS)

Coutinho, Suellen N.; Figueiredo, Ana Maria G.; Quináglia, Gilson A.

2017-01-01

The study of the distribution of metals in sediments is very important from the point of view of environmental pollution once the sediment concentrates metals in aquatic systems and represents a relevant contamination monitor. The analysis of sediments has been used to evaluate the quality of aquatic systems in relation to the concentration of metals. This study aimed to assess sediment contamination by metals in the Guarapiranga Reservoir. Sediment and water samples were analyzed by ICP OES (Inductively Coupled Plasma Optical Emission Spectrometry) for As, Cd, Cr, Cu, Ni, Pb and Zn and by CV AAS (Cold Vapor Atomic Absorption Spectrophotometry) for Hg. The sediment samples results were compared to TEL (Threshold Effect Level) and PEL (Probable Effect Level) guidance values and RRV (Reference Regional Values). Geoaccumulation Index (I geo ) was calculated to evaluate metals pollution degree using reference values established for metals and metalloids in sediments from the Upper Tietê Basin and E H -pH diagrams were applied to explain chemical forms and bioavailability of toxic metals in sediment samples. In general, most of the analyzed elements exceeded TEL values and Cr, Cu and Zn exceeded RRV guidelines. The high concentrations of Cu found in this reservoir can be explained by the frequent application of CuSO 4 algicide, mainly at sampling site S-03. The I geo indicated moderated polluted sediments by Zn and moderately to extremely polluted sediments by Cu, especially at S-03, in agreement with the TEL, PEL and RRV values comparison. These results may indicate potential risk of the reservoir water quality. (author)

Development of Y-BA-CU-O Coated Conductor Using Metal Organic Chemical Vapor Deposition

National Research Council Canada - National Science Library

Selvamanickam, V

2003-01-01

.... The program includes a study of the a) influence of MOCVD processing conditions such as the flow rate of precursor vapors, precursor vaporization temperatures, oxygen partial pressure, reactor pressure, and the deposition temperature...

Inductively coupled plasma--atomic emission spectrometry: trace elements in oil matrices

Energy Technology Data Exchange (ETDEWEB)

Peterson, Charlie Albert [Iowa State Univ., Ames, IA (United States)

1977-12-01

The simultaneous determination of up to 20 trace elements in various oil matrices by inductively coupled plasma-atomic emission spectrometry is reported. The oil matrices investigated were lubricating oils (for wear metals), fuel oil, centrifuged coal liquefaction product, crude soybean oil, and commercial edible oils. The samples were diluted with appropriate organic solvents and injected into the plasma as an aerosol generated by a pneumatic nebulization technique. Detection limits of the 28 elements studied ranged from 0.0006 to 9 μg/g with the majority falling in the 0.01 to 0.1 μg/g range. Analytical calibration curves were linear over at least two orders of magnitude and for some elements this linearity extended over 4.5 orders of magnitude. Relevant data on precision and accuracy are included. Because metals often occur as particles in lubricating oil and coal liquefaction products, the effect of particles on the analytical results was examined. Wear metal particles in used oil did not appear to affect the analytical results. However, incomplete recovery relative to organometallic reference solutions was obtained for iron particles with a nominal mean diameter of 3.0 μm suspended in oil. It was shown that the following factors contributed to incomplete recovery for the particles: settling of the suspended particles in the flask, a difference in nebulization efficiency between particle suspensions and organometallic solutions, and indications of incomplete vaporization of the larger particles in the plasma.

Chemical modeling of a high-density inductively-coupled plasma reactor containing silane

NARCIS (Netherlands)

Kovalgin, Alexeij Y.; Boogaard, A.; Brunets, I.; Holleman, J.; Schmitz, Jurriaan

We carried out the modeling of chemical reactions in a silane-containing remote Inductively Coupled Plasma Enhanced Chemical Vapor Deposition (ICPECVD) system, intended for deposition of silicon, silicon oxide, and silicon nitride layers. The required electron densities and Electron Energy

[Determination of Heavy Metal Elements in Diatomite Filter Aid by Inductively Coupled Plasma Mass Spectrometry].

Science.gov (United States)

Nie, Xi-du; Fu, Liang

2015-11-01

This study established a method for determining Be, Cr, Ni, As, Cd, Sb, Sn, Tl, Hg and Pb, total 10 heavy metals in diatomite filter aid. The diatomite filter aid was digested by using the mixture acid of HNO₃ + HF+ H₃PO₄ in microwave system, 10 heavy metals elements were determined by inductively coupled plasma mass spectrometry (ICP-MS). The interferences of mass spectrometry caused by the high silicon substrate were optimized, first the equipment parameters and isotopes of test metals were selected to eliminate these interferences, the methane was selected as reactant gas, and the mass spectral interferences were eliminated by dynamic reaction cell (DRC). Li, Sc, Y, In and Bi were selected as the internal standard elements to correct the interferences caused by matrix and the drift of sensitivity. The results show that the detection limits for analyte is in the range of 3.29-15.68 ng · L⁻¹, relative standard deviations (RSD) is less than 4.62%, and the recovery is in the range of 90.71%-107.22%. The current method has some advantages such as, high sensitivity, accurate, and precision, which can be used in diatomite filter aid quality control and safety estimations.

Study of hard diamond-like carbon films deposited in an inductively coupled plasma source

International Nuclear Information System (INIS)

Yu Shiji; Ma Tengcai

2003-01-01

Chemical vapor deposition of the hard diamond-like carbon (DLC) films was achieved using an inductively coupled plasma source (ICPS). The microscopy, microhardness, deposition rate and structure characteristic of the DLC films were analyzed. It is shown that the ICPS is suitable for the hard DLC film deposition at relatively low substrate negative bias voltage, and the substrate negative bias voltage greatly affects chemical vapor deposition of the DLC film and its quality

Volcanic sulfur degassing and the role of sulfides in controlling volcanic metal emissions

Science.gov (United States)

Edmonds, M.; Liu, E.

2017-12-01

Volcanoes emit prodigious quantities of sulfur and metals, their behaviour inextricably linked through pre-eruptive sulfide systematics and through degassing and speciation in the volcanic plume. Fundamental differences exist in the metal output of ocean island versus arc volcanoes, with volcanoes in Hawaii and Iceland outgassing large fluxes of gaseous and particulate chalcophiles; and arc volcanoes' plumes, in contrast, enriched in Zn, Cu, Tl and Pb. Metals and metalloids partition into a magmatic vapor phase from silicate melt at crustal pressures. Their abundance in magmatic vapor is influenced strongly by sulfide saturation and by the composition of the magmatic vapor phase, particularly with respect to chloride. These factors are highly dependent on tectonic setting. Metal outgassing is controlled by magma water content and redox: deep saturation in vapor and minimal sulfide in arc basalts yields metal-rich vapor; shallow degassing and resorption of sulfides feeds the metal content of volcanic gas in ocean islands. We present a detailed study of the sulfide systematics of the products of the 2014-2015 Holuhraun basaltic fissure eruption (Bárðarbunga volcanic system, Iceland) to illustrate the interplay between late water and sulfur outgassing; sulfide saturation and breakdown; and metal partitioning into a vapor phase. Sulfide globules, representing quenched droplets of an immiscible sulfide liquid, are preserved within erupted tephra. Sulfide globules in rapidly quenched tephra are preserved within both matrix glass and as inclusions in crystals. The stereologically-corrected 3D size distribution of sulfide globules ranges from importance in supplying sulfur and metals to the atmosphere during eruption.

Production of metal waste forms from spent fuel treatment

International Nuclear Information System (INIS)

Westphal, B.R.; Keiser, D.D.; Rigg, R.H.; Laug, D.V.

1995-01-01

Treatment of spent nuclear fuel at Argonne National Laboratory consists of a pyroprocessing scheme in which the development of suitable waste forms is being advanced. Of the two waste forms being proposed, metal and mineral, the production of the metal waste form utilizes induction melting to stabilize the waste product. Alloying of metallic nuclear materials by induction melting has long been an Argonne strength and thus, the transition to metallic waste processing seems compatible. A test program is being initiated to coalesce the production of the metal waste forms with current induction melting capabilities

Determination of Pt, Pd and Rh in Brassica Napus using solid sampling electrothermal vaporization inductively coupled plasma optical emission spectrometry

International Nuclear Information System (INIS)

Nischkauer, Winfried; Herincs, Esther; Puschenreiter, Markus; Wenzel, Walter; Limbeck, Andreas

2013-01-01

Conventional approaches for the analysis of platinum group elements (PGEs) in plant material suffer from sample digestion which results in sample dilution and therefore requires high sample intakes to maintain the sensitivity. The presented solid-sampling method avoids sample digestion while improving sensitivity when compared to digestion-based inductively coupled plasma optical emission spectrometry (ICP-OES) methods and allows the analysis of sample masses of 5 mg or less. Detection limits of 0.38 μg g −1 , 0.14 μg g −1 and 0.13 μg g −1 were obtained for Pt, Pd and Rh, respectively using a sample intake of 5 mg. The reproducibility of the procedure ranged between 4.7% (Pd) relative standard deviation (RSD, n = 7) and 7.1% (Rh) RSD for 25 ng analytes. For quantification, aqueous standards were applied on paper filter strips and dried. Only the dried filters were introduced into the electrothermal vaporization unit. This approach successfully removed memory-effects observed during analysis of platinum which occurred only if liquid standards came into contact with the graphite material of the furnace. The presented method for overcoming the Pt-memory-effects may be of further interest for the analysis of other carbide-forming analytes as it does not require any technical modification of the graphite furnace (e.g., metal inlays, pyrolytic coating). Owing to lack of suitable certified reference materials, the proposed method was compared with conventional ICP-OES analysis of digested samples and a good agreement was obtained. As a result of the low sample consumption, it was possible to determine the spatial distribution of PGEs within a single plant. Significant differences in PGE concentrations were observed between the shoots (stem, leaves) and the roots. Pd was mainly found in the roots, whereas Pt and Rh were also found in higher concentrations in the shoots. - Highlights: • The uptake of Pt, Pd and Rh by hydroponically grown plants was investigated

Determination of Pt, Pd and Rh in Brassica Napus using solid sampling electrothermal vaporization inductively coupled plasma optical emission spectrometry

Energy Technology Data Exchange (ETDEWEB)

Nischkauer, Winfried [Vienna University of Technology, Institute of Chemical Technologies and Analytics, Division of Instrumental Analytical Chemistry, Getreidemarkt 9/164-IAC, A-1060 Vienna (Austria); Herincs, Esther [Vienna University of Technology, Institute of Chemical Technologies and Analytics, Division of Instrumental Analytical Chemistry, Getreidemarkt 9/164-IAC, A-1060 Vienna (Austria); University of Natural Resources and Life Sciences, Department of Forest and Soil Sciences, Institute of Soil Research, Konrad Lorenz Straße 24, A-3430 Tulln (Austria); Puschenreiter, Markus; Wenzel, Walter [University of Natural Resources and Life Sciences, Department of Forest and Soil Sciences, Institute of Soil Research, Konrad Lorenz Straße 24, A-3430 Tulln (Austria); Limbeck, Andreas, E-mail: A.Limbeck@tuwien.ac.at [Vienna University of Technology, Institute of Chemical Technologies and Analytics, Division of Instrumental Analytical Chemistry, Getreidemarkt 9/164-IAC, A-1060 Vienna (Austria)

2013-11-01

Conventional approaches for the analysis of platinum group elements (PGEs) in plant material suffer from sample digestion which results in sample dilution and therefore requires high sample intakes to maintain the sensitivity. The presented solid-sampling method avoids sample digestion while improving sensitivity when compared to digestion-based inductively coupled plasma optical emission spectrometry (ICP-OES) methods and allows the analysis of sample masses of 5 mg or less. Detection limits of 0.38 μg g{sup −1}, 0.14 μg g{sup −1} and 0.13 μg g{sup −1} were obtained for Pt, Pd and Rh, respectively using a sample intake of 5 mg. The reproducibility of the procedure ranged between 4.7% (Pd) relative standard deviation (RSD, n = 7) and 7.1% (Rh) RSD for 25 ng analytes. For quantification, aqueous standards were applied on paper filter strips and dried. Only the dried filters were introduced into the electrothermal vaporization unit. This approach successfully removed memory-effects observed during analysis of platinum which occurred only if liquid standards came into contact with the graphite material of the furnace. The presented method for overcoming the Pt-memory-effects may be of further interest for the analysis of other carbide-forming analytes as it does not require any technical modification of the graphite furnace (e.g., metal inlays, pyrolytic coating). Owing to lack of suitable certified reference materials, the proposed method was compared with conventional ICP-OES analysis of digested samples and a good agreement was obtained. As a result of the low sample consumption, it was possible to determine the spatial distribution of PGEs within a single plant. Significant differences in PGE concentrations were observed between the shoots (stem, leaves) and the roots. Pd was mainly found in the roots, whereas Pt and Rh were also found in higher concentrations in the shoots. - Highlights: • The uptake of Pt, Pd and Rh by hydroponically grown plants was

Complete long-term corrosion protection with chemical vapor deposited graphene

DEFF Research Database (Denmark)

Yu, Feng; Camilli, Luca; Wang, Ting

2018-01-01

Despite numerous reports regarding the potential of graphene for corrosion protection, examples of chemical vapor deposited (CVD) graphene-based anticorrosive coatings able to provide long-term protection (i.e. several months) of metals have so far been absent. Here, we present a polymer-graphene......Despite numerous reports regarding the potential of graphene for corrosion protection, examples of chemical vapor deposited (CVD) graphene-based anticorrosive coatings able to provide long-term protection (i.e. several months) of metals have so far been absent. Here, we present a polymer......-graphene hybrid coating, comprising two single layers of CVD graphene sandwiched by three layers of polyvinyl butyral, which provides complete corrosion protection of commercial aluminum alloys even after 120 days of exposure to simulated seawater. The essential role played by graphene in the hybrid coating...

The detection of sodium vapor bubble collapse in a liquid metal fast breeder reactor

International Nuclear Information System (INIS)

Carey, W.M.; Gavin, A.P.; Bobis, J.P.; Sheen, S.H.; Anderson, T.T.; Doolittle, R.D.; Albrecht, R.W.

1977-01-01

Sodium boiling detection utilizing the sound pressure emanated during the collapse of a sodium vapour bubble in a subcooled media is discussed in terms of the sound characteristic, the reactor ambient noise background, transmission loss considerations and performance criteria. Data obtained in several loss of flow experiments on Fast Test Reactor Fuel Elements indicate that the collapse of the sodium vapour bubble depends on the presence of a subcooled structure or sodium. The collapse pressure pulse was observed in all cases to be on the order of a kPa, indicating a soft type of cavitational collapse. Spectral examination of the pulses indicates the response function of the test structure and geometry is important. The sodium boiling observed in these experiments was observed to occur at a low ( 0 C) liquid superheat with the rate of occurrence of sodium vapor bubble collapse in the 3 to 30 Hz range. Reactor ambient noise data were found to be due to machinery induced vibrations flow induced vibrations, and flow noise. These data were further found to be weakly stationary enhancing the possibility of acoustic surveillance of an operating Liquid Metal Fast Breeder Reactor. Based on these noise characteristics and extrapolating the noise measurements from the Fast Flux Test Facility Pump (FFTP), one would expect a signal to noise ratio of up to 20 dB in the absence of transmission loss. The requirement of a low false alarm probability is shown to necessitate post detection analysis of the collapse event sequence and the cross correlation with the second derivative of the neutronic boiling detection signal. Sodium boiling detection using the sounds emitted during sodium vapor bubble collapse are shown to be feasible but a need for in-reactor demonstration is necessary. (author)

Evidence for extreme partitioning of copper into a magmatic vapor phase

International Nuclear Information System (INIS)

Lowenstern, J.B.; Mahood, G.A.; Rivers, M.L.; Sutton, S.R.

1991-01-01

The discovery of copper sulfides in carbon dioxide- and chlorine-bearing bubbles in phenocryst-hosted melt inclusions shows that copper resides in a vapor phase in some shallow magma chambers. Copper is several hundred times more concentrated in magmatic vapor than in coexisting pantellerite melt. The volatile behavior of copper should be considered when modeling the volcanogenic contribution of metals to the atmosphere and may be important in the formation of copper porphyry ore deposits

Elastomeric Sensing of Pressure with Liquid Metal and Wireless Inductive Coupling

Science.gov (United States)

Dick, Jacob; Zou, Xiyue; Hogan, Ben; Tumalle, Jonathan; Etikyala, Sowmith; Fung, Diego; Charles, Watley; Gu, Tianye; Hull, Patrick V.; Mazzeo, Aaron D.

2017-01-01

This project describes resistance-based soft sensors filled with liquid metal, which permit measurements of large strains (0 percent to 110 percent), associated with small forces of less than 30 Newtons. This work also demonstrates a methodology for wireless transfer of these strain measurements without connected electrodes. These sensors allow intermittent detection of pressure on soft membranes with low force. Adapting these sensors for passive wireless pressure sensing will eliminate the need for embedded batteries, and will allow the sensors to transmit pressure data through non-conductive materials including glass and acrylic. The absence of batteries allows us to embed these sensors into materials for long-term use because the sensors only use passive analog circuit elements. We found the oxidation of the liquid metal (eutectic gallium indium) plays a role in the repeatability of the soft sensors. We investigated how the oxidation layer affected the behavior of the sensor by encapsulating materials (silicone, fluorosilicone, and PVC) with varied permeabilities to oxygen. We measured the effects of mechanical loading on the oxidation layer and the effects of wireless inductive coupling on the oxidation layer. We concluded our research by investigating the effects of embedding self-resonant circuits into polydimethylsiloxane (PDMS). Efforts to design engineered systems with soft materials are a growing field with progress in soft robotics, epidermal electronics, and wearable electronics. In the field of soft robotics, PDMS-based grippers are capable of picking up delicate objects because their form-fitting properties allow them to conform to the shape of objects more easily than conventional robotic grippers. Epidermal devices also use PDMS as a substrate to hold electronic components such as radios, sensors, and power supply circuits. Additionally, PDMS-based soft sensors can monitor human motion with liquid metal embedded within micro-channels. Passive

In situ synchrotron X-ray studies during metal-organic chemical vapor deposition of semiconductors

Energy Technology Data Exchange (ETDEWEB)

Thompson, Carol [Northern Illinois Univ., DeKalb, IL (United States); Argonne National Lab., Argonne, IL (United States); Highland, Matthew J.; Perret, Edith; Fuoss, Paul H.; Streiffer, Stephen K.; Stephenson, G. Brian [Argonne National Lab., Argonne, IL (United States); Richard, Marie-Ingrid [Universite Paul Cezanne Aix-Marseille, Marseille (France)

2012-07-01

In-situ, time-resolved techniques provide valuable insight into the complex interplay of surface structural and chemical evolution occurring during materials synthesis and processing of semiconductors. Our approach is to observe the evolution of surface structure and morphology at the atomic scale in real-time during metal organic vapor phase deposition (MOCVD) by using grazing incidence x-ray scattering and X-ray fluorescence, coupled with visible light scattering. Our vertical-flow MOCVD chamber is mounted on a 'z-axis' surface diffractometer designed specifically for these studies of the film growth, surface evolution and the interactions within a controlled growth environment. These techniques combine the ability of X-rays to penetrate a complex environment for measurements during growth and processing, with the sensitivity of surface scattering techniques to atomic and nanoscale structure. In this talk, we outline our program and discuss examples from our in-situ and real-time X-ray diffraction and fluorescence studies of InN, GaN, and InGaN growth on GaN(0001).

Uptake of mercury vapor by wheat. An assimilation model

International Nuclear Information System (INIS)

Browne, C.L.; Fang, S.C.

1978-01-01

Using a whole-plant chamber and 203 Hg-labeled mercury, a quantitative study was made of the effect of environmental parameters on the uptake, by wheat (Triticum aestivum), of metallic mercury vapor, an atmospheric pollutant. Factors were examined in relation to their influence on components of the gas-assimilation model, U(Hg) = (C/sub A' -- C/sub L')/(r/sub L.Hg/ + r/sub M.Hg/) where U(Hg) is the rate of mercury uptake per unit leaf surface, C/sub A'/ is the ambient mercury vapor concentration, C/sub L'/ is the mercury concentration at immobilization sites within the plant (assumed to be zero), r/sub L.Hg/ is the total leaf resistance to mercury vapor exchange, and r/sub M.Hg/ is a residual term to account for unexplained physical and biochemical resistances to mercury vapor uptake. Essentially all mercury vapor uptake was confined to the leaves. r/sub L.Hg/ was particularly influenced by illumination (0 to 12.8 klux), but unaffected by ambient temperature (17 to 33 0 C) and mercury vapor concentration (0 to 40 μg m -3 ). The principal limitation to mercury vapor uptake was r/sub M.Hg/, which was linearly related to leaf temperature, but unaffected by mercury vapor concentration and illumination, except for apparent high values in darkness. Knowing C/sub A'/ and estimating r/sub L.Hg/ and r/sub M.Hg/ from experimental data, mercury vapor uptake by wheat in light was accurately predicted for several durations of exposure using the above model

Induction melting of simulated transuranic waste

International Nuclear Information System (INIS)

Tenaglia, R.D.; McCall, J.L.

1983-06-01

Coreless induction melting was investigated as a method to melt and consolidate waste material representative of the transuranic waste (TRU) stored at the Idaho National Engineering Laboratory (INEL). Waste material was introduced onto the surface of a molten cast iron bath in a coreless induction furnace. Waste metallics were incorporated into the bath. Noncombustibles formed a slag which was poured or skimmed from the bath surface. Stack sampling was performed to characterize the off-gas and particulate matter evolved. Experimental melting tests were performed for a variety of types of wastes including metallics, chemical sludge, soil, concrete, and glass. Each test also included a representative level of combustible materials consisting of paper, wood, cloth, polyvinyl chloride and polyethylene. Metallic wastes were readily processed by induction melting with a minimum of slag production. Test waste consisting primarily of chemical sludge provided fluid slags which could be poured from the bath surface. Processing of wastes consisting of soil, concrete, or glass was limited by the inability to achieve fluid slags. It appears from test results that coreless induction melting is a feasible method to process INEL-type waste materials if two problems can be resolved. First, slag fluidity must be improved to facilitate the collection of slags formed from soil, concrete, or glass containing wastes. Secondly, refractory life must be further optimized to permit prolonged processing of the waste materials. The use of a chrome-bearing high-alumina refractory was found to resist slag line attach much better than a magnesia refractory, although some attack was still noted

Method of purifying zirconium tetrachloride and hafnium tetrachloride in a vapor stream

International Nuclear Information System (INIS)

Snyder, T.S.; Stolz, R.A.

1992-01-01

This patent describes a method of purifying zirconium tetrachloride and hafnium tetrachloride in a vapor stream from a sand chlorinator in which the silicon and metals present in sand fed to the chlorinator are converted to chlorides at temperatures over about 800 degrees C. It comprises cooling a vapor stream from a sand chlorinator, the vapor stream containing principally silicon tetrachloride, zirconium tetrachloride, and hafnium tetrachloride contaminated with ferric chloride, to a temperature of from about 335 degrees C to about 600 degrees C; flowing the vapor stream through a gaseous diffusion separative barrier to produce a silicon tetrachloride-containing vapor stream concentrated in zirconium tetrachloride and hafnium tetrachloride and a silicon tetrachloride-containing vapor stream depleted in zirconium tetrachloride and hafnium tetrachloride; adsorbing the ferric chloride in the separative barrier; and recovering the silicon tetrachloride stream concentrated in zirconium tetrachloride and hafnium tetrachloride separately from the silicon tetrachloride stream depleted in zirconium tetrachloride and hafnium tetrachloride

Vapor pressures and enthalpies of vaporization of azides

International Nuclear Information System (INIS)

Verevkin, Sergey P.; Emel'yanenko, Vladimir N.; Algarra, Manuel; Manuel Lopez-Romero, J.; Aguiar, Fabio; Enrique Rodriguez-Borges, J.; Esteves da Silva, Joaquim C.G.

2011-01-01

Highlights: → We prepared and measured vapor pressures and vaporization enthalpies of 7 azides. → We examined consistency of new and available in the literature data. → Data for geminal azides and azido-alkanes selected for thermochemical calculations. - Abstract: Vapor pressures of some azides have been determined by the transpiration method. The molar enthalpies of vaporization Δ l g H m of these compounds were derived from the temperature dependencies of vapor pressures. The measured data sets were successfully checked for internal consistency by comparison with vaporization enthalpies of similarly structured compounds.

PULSAR: an inductive pulse power source

International Nuclear Information System (INIS)

Cnare, E.C.; Brooks, W.P.; Cowan, M.

1979-01-01

The PULSAR concept of inductive pulsed power source uses a flux-compressing metallic or plasma armature rather than a fast opening switch to transfer magnetic flux to a load. The inductive store may be a relatively unsophisticated dc superconducting magnet since no magnetic energy is taken from it, and no large current transients are induced in it. Initial experimental efforts employed either expendable or reusable metallic armatures with a 200 kJ, 450 mm diameter superconducting magnet. Attention is now being focused on the development of much faster plasma armatures for use in larger systems of one and two meters diameter. Techniques used to generate the required high magnetic Reynolds number flow will be described and initial experimental results will be presented

Cu-Al alloy formation by thermal annealing of Cu/Al multilayer films deposited by cyclic metal organic chemical vapor deposition

Science.gov (United States)

Moon, Hock Key; Yoon, Jaehong; Kim, Hyungjun; Lee, Nae-Eung

2013-05-01

One of the most important issues in future Cu-based interconnects is to suppress the resistivity increase in the Cu interconnect line while decreasing the line width below 30 nm. For the purpose of mitigating the resistivity increase in the nanoscale Cu line, alloying Cu with traces of other elements is investigated. The formation of a Cu alloy layer using chemical vapor deposition or electroplating has been rarely studied because of the difficulty in forming Cu alloys with elements such as Al. In this work, Cu-Al alloy films were successfully formed after thermal annealing of Cu/Al multilayers deposited by cyclic metal-organic chemical vapor deposition (C-MOCVD). After the C-MOCVD of Cu/Al multilayers without gas phase reaction between the Cu and Al precursors in the reactor, thermal annealing was used to form Cu-Al alloy films with a small Al content fraction. The resistivity of the alloy films was dependent on the Al precursor delivery time and was lower than that of the aluminum-free Cu film. No presence of intermetallic compounds were detected in the alloy films by X-ray diffraction measurements and transmission electron spectroscopy.

Metal assessment in sediments from the Guarapiranga Reservoir

Energy Technology Data Exchange (ETDEWEB)

Coutinho, Suellen N.; Figueiredo, Ana Maria G. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Quináglia, Gilson A., E-mail: sncoutinho@usp.br, E-mail: anamaria@ipen.br, E-mail: gquinaglia@sp.gov.br [Companhia Ambiental do Estado de São Paulo (CETESB), São Paulo, SP (Brazil)

2017-07-01

The study of the distribution of metals in sediments is very important from the point of view of environmental pollution once the sediment concentrates metals in aquatic systems and represents a relevant contamination monitor. The analysis of sediments has been used to evaluate the quality of aquatic systems in relation to the concentration of metals. This study aimed to assess sediment contamination by metals in the Guarapiranga Reservoir. Sediment and water samples were analyzed by ICP OES (Inductively Coupled Plasma Optical Emission Spectrometry) for As, Cd, Cr, Cu, Ni, Pb and Zn and by CV AAS (Cold Vapor Atomic Absorption Spectrophotometry) for Hg. The sediment samples results were compared to TEL (Threshold Effect Level) and PEL (Probable Effect Level) guidance values and RRV (Reference Regional Values). Geoaccumulation Index (I{sub geo}) was calculated to evaluate metals pollution degree using reference values established for metals and metalloids in sediments from the Upper Tietê Basin and E{sub H}-pH diagrams were applied to explain chemical forms and bioavailability of toxic metals in sediment samples. In general, most of the analyzed elements exceeded TEL values and Cr, Cu and Zn exceeded RRV guidelines. The high concentrations of Cu found in this reservoir can be explained by the frequent application of CuSO{sub 4} algicide, mainly at sampling site S-03. The I{sub geo} indicated moderated polluted sediments by Zn and moderately to extremely polluted sediments by Cu, especially at S-03, in agreement with the TEL, PEL and RRV values comparison. These results may indicate potential risk of the reservoir water quality. (author)

Ion spectra of the metal vapor vacuum arc ion source with compound and alloy cathodes

Science.gov (United States)

Sasaki, Jun; Brown, Ian G.

1990-01-01

In metal vapor vacuum arc (MEVVA) ion sources, vacuum arc plasma with cathodes of single, pure elements has been utilized for the production of metal ions. In this study, we have investigated the charge state distributions of ions produced in vacuum arc plasmas in a MEVVA ion source for the case when the cathode is an alloy or a compound material. The ion charge state spectra were analyzed by means of a time-of-flight apparatus. We have compared the ion spectra for a cathode of an alloy or a compound material with its constituent elements: TiC/TiN/TiO2/Ti/C, SiC/Si/C, WC/W/C U/UN/(UN-ZrC)/Zr/C, and brass/Zn/Cu. We find that the MEVVA produces ions of all constituent elements in the compound and the alloy cathodes. The charge state distribution of each element differs, however, from the charge state distribution obtained in the vacuum arc with a cathode made of the pure, single constituent element. Fractional values of the total ion numbers of each constituent element in the extracted beam depart from the stoichiometry of the elements in the cathode material. In an operation with a TiC cathode, we irradiated a 304 stainless-steel plate with the extracted beam. Results from glow-discharge spectroscopy (GDS) of the surface show that both titanium and carbon are implanted in the substrate after the irradiation.

Recoverying device for sodium vapor in inert gas

Energy Technology Data Exchange (ETDEWEB)

Nakagawa, Tamotsu; Nagashima, Ikuo

1992-11-06

A multi-pipe type heat exchanger for cooling an inert gas and a mist trap connected to the inert gas exit of the heat exchanger are disposed. A mist filter having bottomed pipes made of an inert gas-permeable sintered metal is disposed in the mist trap, and an inert gas discharge port is disposed at the upper side wall. With such a constitution, a high temperature inert gas containing sodium vapors can be cooled efficiently by the multi-pipe type heat exchanger capable of easy temperature control, thereby converting sodium vapors into mists, and the inert gas containing sodium mists can be flown into the mist trap. Sodium mists are collected by the mist filter and sodium mists flown down are discharged from the discharge port. With such procedures, a great amount of the inert gas containing sodium vapors can be processed continuously. (T.M.).

Container for liquid metal

International Nuclear Information System (INIS)

Abe, Yoshihito; Imazu, Takayuki; Ueda, Sabuo; Ueya, Katsumi.

1980-01-01

Purpose: To arrange a vapor trapping member of a specific structure at the inlet part of a cylindrical gap formed by the inner peripheral surface of the circular opening of a container and the outer peripheral surface of a rotary plug thereby to prevent ingress of vapor in the upper part of the cylindrical gap for a long period of time. Constitution: A sealing material receiving tray is fitted to the container side of the inlet part of a cylindrical gap, and a partition plate is fitted to the rotary plug side. The tray is filled with a sealing material consisting of a large number of steel balls, mesh wire gages and the like, and the partition plate is placed in the tray thereby to carry out sealing of the container. Liquid metal vapor evaporating from the liquid level of the liquid metal adheres to the sealing material to fill the gap, and therefore ingress of vapor to the upper part of the cylindrical gap is prevented, and there is no possibility of causing seal cutting due to the use for a long period. (Sekiya, K.)

Collapsing criteria for vapor film around solid spheres as a fundamental stage leading to vapor explosion

Energy Technology Data Exchange (ETDEWEB)

Freud, Roy [Nuclear Research Center - Negev, Beer-Sheva (Israel)], E-mail: freud@bgu.ac.il; Harari, Ronen [Nuclear Research Center - Negev, Beer-Sheva (Israel); Sher, Eran [Pearlstone Center for Aeronautical Studies, Department of Mechanical Engineering, Ben-Gurion University, Beer-Sheva (Israel)

2009-04-15

Following a partial fuel-melting accident, a Fuel-Coolant Interaction (FCI) can result with the fragmentation of the melt into tiny droplets. A vapor film is then formed between the melt fragments and the coolant, while preventing a contact between them. Triggering, propagation and expansion typically follow the premixing stage. In the triggering stage, vapor film collapse around one or several of the fragments occurs. This collapse can be the result of fragments cooling, a sort of mechanical force, or by any other means. When the vapor film collapses and the coolant re-establishes contact with the dry surface of the hot melt, it may lead to a very rapid and rather violent boiling. In the propagation stage the shock wave front leads to stripping of the films surrounding adjacent droplets which enhance the fragmentation and the process escalates. During this process a large quantity of liquid vaporizes and its expansion can result in destructive mechanical damage to the surrounding structures. This multiphase thermal detonation in which high pressure shock wave is formed is regarded as 'vapor explosion'. The film boiling and its possible collapse is a fundamental stage leading to vapor explosion. If the interaction of the melt and the coolant does not result in a film boiling, no explosion occurs. Many studies have been devoted to determine the minimum temperature and heat flux that is required to maintain a film boiling. The present experimental study examines the minimum temperature that is required to maintain a film boiling around metal spheres immersed into a liquid (subcooled distilled water) reservoir. In order to simulate fuel fragments that are small in dimension and has mirror-like surface, small spheres coated with anti-oxidation layer were used. The heat flux from the spheres was calculated from the sphere's temperature profiles and the sphere's properties. The vapor film collapse was associated with a sharp rise of the heat flux

Collapsing criteria for vapor film around solid spheres as a fundamental stage leading to vapor explosion

International Nuclear Information System (INIS)

Freud, Roy; Harari, Ronen; Sher, Eran

2009-01-01

Following a partial fuel-melting accident, a Fuel-Coolant Interaction (FCI) can result with the fragmentation of the melt into tiny droplets. A vapor film is then formed between the melt fragments and the coolant, while preventing a contact between them. Triggering, propagation and expansion typically follow the premixing stage. In the triggering stage, vapor film collapse around one or several of the fragments occurs. This collapse can be the result of fragments cooling, a sort of mechanical force, or by any other means. When the vapor film collapses and the coolant re-establishes contact with the dry surface of the hot melt, it may lead to a very rapid and rather violent boiling. In the propagation stage the shock wave front leads to stripping of the films surrounding adjacent droplets which enhance the fragmentation and the process escalates. During this process a large quantity of liquid vaporizes and its expansion can result in destructive mechanical damage to the surrounding structures. This multiphase thermal detonation in which high pressure shock wave is formed is regarded as 'vapor explosion'. The film boiling and its possible collapse is a fundamental stage leading to vapor explosion. If the interaction of the melt and the coolant does not result in a film boiling, no explosion occurs. Many studies have been devoted to determine the minimum temperature and heat flux that is required to maintain a film boiling. The present experimental study examines the minimum temperature that is required to maintain a film boiling around metal spheres immersed into a liquid (subcooled distilled water) reservoir. In order to simulate fuel fragments that are small in dimension and has mirror-like surface, small spheres coated with anti-oxidation layer were used. The heat flux from the spheres was calculated from the sphere's temperature profiles and the sphere's properties. The vapor film collapse was associated with a sharp rise of the heat flux during the cooling

A review of refractory materials for vapor-anode AMTEC cells

Science.gov (United States)

King, Jeffrey C.; El-Genk, M. S.

2000-01-01

Recently, refractory alloys have been considered as structural materials for vapor-anode Alkali Metal Thermal-to-Electric Conversion (AMTEC) cells, for extended (7-15 years) space missions. This paper reviewed the existing database for refractory metals and alloys of potential use as structural materials for vapor-anode sodium AMTEC cells. In addition to requiring that the vapor pressure of the material be below 10-9 torr (133 nPa) at a typical hot side temperature of 1200 K, other screening considerations were: (a) low thermal conductivity, low thermal radiation emissivity, and low linear thermal expansion coefficient; (b) low ductile-to-brittle transition temperature, high yield and rupture strengths and high strength-to-density ratio; and (c) good compatibility with the sodium AMTEC operating environment, including high corrosion resistance to sodium in both the liquid and vapor phases. Nb-1Zr (niobium-1% zirconium) alloy is recommended for the hot end structures of the cell. The niobium alloy C-103, which contains the oxygen gettering elements zirconium and hafnium as well as titanium, is recommended for the colder cell structure. This alloy is stronger and less thermally conductive than Nb-1Zr, and its use in the cell wall reduces parasitic heat losses by conduction to the condenser. The molybdenum alloy Mo-44.5Re (molybdenum-44.5% rhenium) is also recommended as a possible alternative for both structures if known problems with oxygen pick up and embrittlement of the niobium alloys proves to be intractable. .

Mass spectrometric study of vaporization of (U,Pu)O2 fuel simulating high burnup

International Nuclear Information System (INIS)

Maeda, Atsushi; Ohmichi, Toshihiko; Fukushima, Susumu; Handa, Muneo

1985-08-01

The vaporization behavior of (U,Pu)O 2 fuel simulatig high burnup was studied in the temperature range of 1,573 -- 2,173 K by high temperature mass spectrometry. The phases in the simulated fuel were examined by X-ray microprobe analysis. The relationship between chemical form and vaporization behavior of simulated fission product elements was discussed. Pd, Sr, Ba, Ce and actinide-bearing vapor species were observed, and it was clarified that Pd vapor originated from metallic inclusion and Sr and Ce vapors, from mixed oxide fuel matrix. The vaporization behavior of the actinide elements was somewhat similar to that of hypostoichiometric mixed oxide fuel. The behavior of Ba-bearing vapor species changed markedly over about 2,000 K. From the determination of BaO vapor pressures over simulated fuel and BaZrO 3 , it was revealed thermodynamically that the transformation of the chemical form of Ba about 2,000 K, i.e., dissolution of BaZrO 3 phase into fuel matrix, might be the reason of the observed vapor pressure change. (author)

Epitaxial Pb(Mg1/3Nb2/3)O3 thin films synthesized by metal-organic chemical vapor deposition

International Nuclear Information System (INIS)

Bai, G. R.; Streiffer, S. K.; Baumann, P. K.; Auciello, O.; Ghosh, K.; Stemmer, S.; Munkholm, A.; Thompson, Carol; Rao, R. A.; Eom, C. B.

2000-01-01

Metal-organic chemical vapor deposition was used to prepare Pb(Mg 1/3 Nb 2/3 )O 3 (PMN) thin films on (001) SrTiO 3 and SrRuO 3 /SrTiO 3 substrates, using solid Mg β-diketonate as the Mg precursor. Parameters including the precursor ratio in the vapor phase, growth temperature, growth rate, and reaction pressure in the reactor chamber were varied in order to determine suitable growth conditions for producing phase-pure, epitaxial PMN films. A cube-on-cube orientation relationship between the thin film and the SrTiO 3 substrate was found, with a (001) rocking curve width of 0.1 degree sign , and in-plane rocking-curve width of 0.8 degree sign . The root-mean-square surface roughness of a 200-nm-thick film on SrTiO 3 was 2 to 3 nm as measured by scanning probe microscopy. The zero-bias dielectric constant and loss measured at room temperature and 10 kHz for a 200-nm-thick film on SrRuO 3 /SrTiO 3 were approximately 1100 and 2%, respectively. The remnant polarization for this film was 16 μC/cm 2 . (c) 2000 American Institute of Physics

On-line system for preconcentration and determination of metals in vegetables by Inductively Coupled Plasma Optical Emission Spectrometry

International Nuclear Information System (INIS)

Bezerra, Marcos A.; Santos, Walter N.L. dos; Lemos, Valfredo A.; Korn, Maria das Gracas A.; Ferreira, Sergio L.C.

2007-01-01

A procedure has been developed for the simultaneous determination of trace amounts of cadmium, copper, chromium, nickel and lead in digested vegetable samples. The method involves solid-phase extraction of the metals using a minicolumn of Amberlite XAD-4 modified with dihydroxybenzoic acid (DHB) and detection by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The elution of the metals from minicolumn was performed with 1.0 mol L -1 hydrochloric acid. Variables associated with flow preconcentration system performance, such as pH, buffer concentration, eluent concentration and sampling flow rate, were optimized. The developed procedure provides enrichment factors of 100, 72, 16, 91 and 53, for cadmium, copper, chromium, nickel and lead, respectively. Detection limits (3σ B ) were 0.02 (Cd), 0.23 (Cu), 0.58 (Cr), 0.060 (Ni) and 0.54 (Pb) μg L -1 . The procedure was applied for determination of metals in samples of guarana and cabbage. The accuracy of the method was checked by the analysis of a certified reference material (NIST 1571, Orchard leaves). Results found were in agreement with certified values

Colorimetric Detection of Water Vapor Using Metal-Organic Framework Composites.

Energy Technology Data Exchange (ETDEWEB)

Allendorf, Mark D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-12-01

Purpose: Water vapor trapped in encapsulation materials or enclosed volumes leads to corrosion issues for critical NW components. Sandia National Laboratories has created a new diagnostic to indicate the presence of water in weapon systems. Impact: Component exposure to water now can be determined instantly, without need for costly, time-consuming analytical methods.

Theoretical Investigation of the Structural Stabilities of Ceria Surfaces and Supported Metal Nanocluster in Vapor and Aqueous Phases

Energy Technology Data Exchange (ETDEWEB)

Ren, Zhibo [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China; Institute for Integrated Catalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Liu, Ning [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China; Institute for Integrated Catalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Chen, Biaohua [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China; Li, Jianwei [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China; Mei, Donghai [Institute for Integrated Catalysis, Pacific Northwest National Laboratory, Richland, Washington 99352, United States

2018-01-25

Understanding the structural stability and dynamics at the interface between the solid metal oxide and aqueous phase is significant in a variety of industrial applications including heterogeneous catalysis and environmental remediation. In the present work, the stabilities of three low-index ceria (CeO2) surfaces, i.e., (111), (110) and (100) in vapor and aqueous phases were studied using ab initio molecular dynamics simulations and density functional theory (DFT) calculations. Gibbs surface free energies as a function of temperature, water partial pressure, and water coverages were calculated using DFT based atomistic thermodynamic approach. On the basis of surface free energies, the morphology and exposed surface structures of the CeO2 nanoparticle were predicted using Wulff construction principle. It is found that the partially hydroxylated (111) and (100) are two major surface structures of CeO2 nanoparticles in vapor phase at ambient temperature (300 K). As the temperature increases, the fully dehydrated (111) surface gradually becomes the most dominant surface structure. While in aqueous phase, the exposed surface of the CeO2 nanoparticle is dominated by the hydroxylated (110) structure at 393 K. Finally, the morphology and stability of a cuboctahedron Pt13 nanocluster supported on CeO2 surfaces in both gas and aqueous phases were investigated. In gas phase, the supported Pt13 nanocluster has the tendency to wetting the CeO2 surface due to the strong metal-support interaction. The calculated interaction energies suggest the CeO2(110) surface provides the best stability for the Pt13 nanocluster. The CeO2 supported Pt13 nanoclusters are oxidized. Compared to the gas phase, the morphology of the CeO2 supported Pt13 nanocluster is less distorted due to the solvation effect provided by surrounding water molecules in aqueous phase. More electrons are transferred from the Pt13 nanocluster to the CeO2 support, implying the supported Pt13 nanocluster is further

Modelling of gas-metal arc welding taking into account metal vapour

Energy Technology Data Exchange (ETDEWEB)

Schnick, M; Fuessel, U; Hertel, M; Haessler, M [Institute of Surface and Manufacturing Technology, Technische Universitaet Dresden, D-01062 Dresden (Germany); Spille-Kohoff, A [CFX Berlin Software GmbH, Karl-Marx-Allee 90, 10243 Berlin (Germany); Murphy, A B [CSIRO Materials Science and Engineering, PO Box 218, Lindfield NSW 2070 (Australia)

2010-11-03

The most advanced numerical models of gas-metal arc welding (GMAW) neglect vaporization of metal, and assume an argon atmosphere for the arc region, as is also common practice for models of gas-tungsten arc welding (GTAW). These models predict temperatures above 20 000 K and a temperature distribution similar to GTAW arcs. However, spectroscopic temperature measurements in GMAW arcs demonstrate much lower arc temperatures. In contrast to measurements of GTAW arcs, they have shown the presence of a central local minimum of the radial temperature distribution. This paper presents a GMAW model that takes into account metal vapour and that is able to predict the local central minimum in the radial distributions of temperature and electric current density. The influence of different values for the net radiative emission coefficient of iron vapour, which vary by up to a factor of hundred, is examined. It is shown that these net emission coefficients cause differences in the magnitudes, but not in the overall trends, of the radial distribution of temperature and current density. Further, the influence of the metal vaporization rate is investigated. We present evidence that, for higher vaporization rates, the central flow velocity inside the arc is decreased and can even change direction so that it is directed from the workpiece towards the wire, although the outer plasma flow is still directed towards the workpiece. In support of this thesis, we have attempted to reproduce the measurements of Zielinska et al for spray-transfer mode GMAW numerically, and have obtained reasonable agreement.

Saturated vapor pressure over molten mixtures of GaCl{sub 3} and alkali metal chlorides; Davlenie nasyshchennykh parov rasplavlennykh smesej CaCl{sub 3} s khloridami shchelochnykh metallov

Energy Technology Data Exchange (ETDEWEB)

Salyulev, A B; Smolenskij, V V; Moskalenko, N I [UrO RAN, Inst. Vysokotemperaturnoj Ehlektrokhimii, Elaterinburg (Russian Federation)

2004-07-01

Volatilities of GaCl{sub 3} and alkali metal chlorides over diluted (up to 3 mol %) solutions of GaCl{sub 3} in LiCl, NaCl, KCl, RbCl, and CsCl were measured at 1100 K by dynamic and indirect static methods. Chemical composition of saturated vapor over the mixed melts was determined. Partial pressures of the components were calculated. Their values depend essentially on specific alkali metal cation and on concentration of GaCl{sub 3}; their variation permits altering parameters of GaCl{sub 3} distillation from the salt melt in a wide range.

Systematic approach to optimal design of induction heating installations for aluminum extrusion process

Science.gov (United States)

Zimin, L. S.; Sorokin, A. G.; Egiazaryan, A. S.; Filimonova, O. V.

2018-03-01

An induction heating system has a number of inherent benefits compared to traditional heating systems due to a non-contact heating process. It is widely used in vehicle manufacture, cast-rolling, forging, preheating before rolling, heat treatment, galvanizing and so on. Compared to other heating technologies, induction heating has the advantages of high efficiency, fast heating rate and easy control. The paper presents a new systematic approach to the design and operation of induction heating installations (IHI) in aluminum alloys production. The heating temperature in industrial complexes “induction heating - deformation” is not fixed in advance, but is determined in accordance with the maximization or minimization of the total economic performance during the process of metal heating and deformation. It is indicated that the energy efficient technological complex “IHI – Metal Forming (MF)” can be designed only with regard to its power supply system (PSS). So the task of designing systems of induction heating is to provide, together with the power supply system and forming equipment, the minimum energy costs for the metal retreating.

Nanoscale leakage current measurements in metal organic chemical vapor deposition crystalline SrTiO3 films

International Nuclear Information System (INIS)

Rozier, Y.; Gautier, B.; Hyvert, G.; Descamps, A.; Plossu, C.; Dubourdieu, C.; Ducroquet, F.

2009-01-01

The properties of SrTiO 3 thin films, grown by liquid injection metal organic chemical vapor deposition on Si/SiO 2 , using a mixture of precursors, have been investigated at the nanoscale using an Atomic Force Microscope in the so-called Conductive Atomic Force Microscopy mode. Maps of the leakage currents with a nanometric resolution have been obtained on films elaborated at different temperatures and stoichiometries in order to discriminate the role of each parameter on the onset of leakage currents in the resulting layers. It appears that the higher the deposition temperature, the higher the leakage currents of the films. The mapping with a nanometric precision allows to show a heterogeneous behaviour of the surface with leaky grains and insulating boundaries. The study of films elaborated at the same temperature with different compositions supports the assumption that the leakage currents on Ti-rich layers are far higher than on Sr-rich layers

Growth of InAs Quantum Dots on Germanium Substrate Using Metal Organic Chemical Vapor Deposition Technique

Directory of Open Access Journals (Sweden)

Tyagi Renu

2009-01-01

Full Text Available Abstract Self-assembled InAs quantum dots (QDs were grown on germanium substrates by metal organic chemical vapor deposition technique. Effects of growth temperature and InAs coverage on the size, density, and height of quantum dots were investigated. Growth temperature was varied from 400 to 450 °C and InAs coverage was varied between 1.40 and 2.35 monolayers (MLs. The surface morphology and structural characteristics of the quantum dots analyzed by atomic force microscope revealed that the density of the InAs quantum dots first increased and then decreased with the amount of InAs coverage; whereas density decreased with increase in growth temperature. It was observed that the size and height of InAs quantum dots increased with increase in both temperature and InAs coverage. The density of QDs was effectively controlled by growth temperature and InAs coverage on GaAs buffer layer.

Investigation of anti-Relaxation coatings for alkali-metal vapor cells using surface science techniques

Energy Technology Data Exchange (ETDEWEB)

Seltzer, S. J.; Michalak, D. J.; Donaldson, M. H.; Balabas, M. V.; Barber, S. K.; Bernasek, S. L.; Bouchiat, M.-A.; Hexemer, A.; Hibberd, A. M.; Jackson Kimball, D. F.; Jaye, C.; Karaulanov, T.; Narducci, F. A.; Rangwala, S. A.; Robinson, H. G.; Shmakov, A. K.; Voronov, D. L.; Yashchuk, V. V.; Pines, A.; Budker, D.

2010-10-11

Many technologies based on cells containing alkali-metal atomic vapor benefit from the use of antirelaxation surface coatings in order to preserve atomic spin polarization. In particular, paraffin has been used for this purpose for several decades and has been demonstrated to allow an atom to experience up to 10?000 collisions with the walls of its container without depolarizing, but the details of its operation remain poorly understood. We apply modern surface and bulk techniques to the study of paraffin coatings in order to characterize the properties that enable the effective preservation of alkali spin polarization. These methods include Fourier transform infrared spectroscopy, differential scanning calorimetry, atomic force microscopy, near-edge x-ray absorption fine structure spectroscopy, and x-ray photoelectron spectroscopy. We also compare the light-induced atomic desorption yields of several different paraffin materials. Experimental results include the determination that crystallinity of the coating material is unnecessary, and the detection of C=C double bonds present within a particular class of effective paraffin coatings. Further study should lead to the development of more robust paraffin antirelaxation coatings, as well as the design and synthesis of new classes of coating materials.

Ultra-fast boriding of metal surfaces for improved properties

Science.gov (United States)

Timur, Servet; Kartal, Guldem; Eryilmaz, Osman L.; Erdemir, Ali

2015-02-10

A method of ultra-fast boriding of a metal surface. The method includes the step of providing a metal component, providing a molten electrolyte having boron components therein, providing an electrochemical boriding system including an induction furnace, operating the induction furnace to establish a high temperature for the molten electrolyte, and boriding the metal surface to achieve a boride layer on the metal surface.

Direct synthesis of metal complexes starting from zero-valent metals

Energy Technology Data Exchange (ETDEWEB)

Gojon-Zorrilla, Gabriel; Kharisov, Boris I. [Universidad Autonoma de Nuevo Leon, Monterrey, Nuevo Leon (Mexico); Garnovskii, Alexander D. [Institute of Physical and Organic Chemistry (Russian Federation)

1996-06-01

The recent (1980-1994) literature on metal-vapor synthesis of coordination and organometallic compounds is reviewed. An account is given of the high-and low-temperature reactions between free metal atoms and a large variety of substrates, mainly alkenes, alkynes, dienes, arenes, funtionalized arenes, alkyl halides {beta}-diketones and simple inorganic molecules. The main experimental methods are described, as well as the results obtained thereby. It is shown that in many instances these methods present significant advantages over conventional synthetic procedures, offering unique access to some metal complexes. [Spanish] Se reviso la literatura reciente (1980-1994) sobre la sintesis de compuestos de coordinacion y compuestos organometalicos a partir de vapores metalicos. Se examinan las reacciones de los atomos metalicos libres con una gran variedad de substratos, principalmente alquenos, alquinos, dienos, hidrocarburos aromaticos y sus derivados, haluros de alquilo y arilo, {beta}-dicetonas y moleculas inorganicas simples. Se presentan los principales metodos experimentales, asi como los resultados obtenidos; se concluye que la crisintesis presenta en muchos casos ventajas significativas sobre los procedimientos sinteticos tradicionales, constituyendo frecuentemente la unica opcion disponible.

Microstructure of vapor deposited coatings on curved substrates

Energy Technology Data Exchange (ETDEWEB)

Rodgers, Theron M.; Zhao, Hengbei; Wadley, Haydn N. G., E-mail: haydn@virginia.edu [Department of Materials Science and Engineering, University of Virginia, 395 McCormick Rd., P.O. Box 400745, Charlottesville, Virginia 22904 (United States)

2015-09-15

Thermal barrier coating systems consisting of a metallic bond coat and ceramic over layer are widely used to extend the life of gas turbine engine components. They are applied using either high-vacuum physical vapor deposition techniques in which vapor atoms rarely experience scattering collisions during propagation to a substrate, or by gas jet assisted (low-vacuum) vapor deposition techniques that utilize scattering from streamlines to enable non-line-of-sight deposition. Both approaches require substrate motion to coat a substrate of complex shape. Here, direct simulation Monte Carlo and kinetic Monte Carlo simulation methods are combined to simulate the deposition of a nickel coating over the concave and convex surfaces of a model airfoil, and the simulation results are compared with those from experimental depositions. The simulation method successfully predicted variations in coating thickness, columnar growth angle, and porosity during both stationary and substrate rotated deposition. It was then used to investigate a wide range of vapor deposition conditions spanning high-vacuum physical vapor deposition to low-vacuum gas jet assisted vapor deposition. The average coating thickness was found to increase initially with gas pressure reaching a maximum at a chamber pressure of 8–10 Pa, but the best coating thickness uniformity was achieved under high vacuum deposition conditions. However, high vacuum conditions increased the variation in the coatings pore volume fraction over the surface of the airfoil. The simulation approach was combined with an optimization algorithm and used to investigate novel deposition concepts to tailor the local coating thickness.

Microstructure of vapor deposited coatings on curved substrates

International Nuclear Information System (INIS)

Rodgers, Theron M.; Zhao, Hengbei; Wadley, Haydn N. G.

2015-01-01

Thermal barrier coating systems consisting of a metallic bond coat and ceramic over layer are widely used to extend the life of gas turbine engine components. They are applied using either high-vacuum physical vapor deposition techniques in which vapor atoms rarely experience scattering collisions during propagation to a substrate, or by gas jet assisted (low-vacuum) vapor deposition techniques that utilize scattering from streamlines to enable non-line-of-sight deposition. Both approaches require substrate motion to coat a substrate of complex shape. Here, direct simulation Monte Carlo and kinetic Monte Carlo simulation methods are combined to simulate the deposition of a nickel coating over the concave and convex surfaces of a model airfoil, and the simulation results are compared with those from experimental depositions. The simulation method successfully predicted variations in coating thickness, columnar growth angle, and porosity during both stationary and substrate rotated deposition. It was then used to investigate a wide range of vapor deposition conditions spanning high-vacuum physical vapor deposition to low-vacuum gas jet assisted vapor deposition. The average coating thickness was found to increase initially with gas pressure reaching a maximum at a chamber pressure of 8–10 Pa, but the best coating thickness uniformity was achieved under high vacuum deposition conditions. However, high vacuum conditions increased the variation in the coatings pore volume fraction over the surface of the airfoil. The simulation approach was combined with an optimization algorithm and used to investigate novel deposition concepts to tailor the local coating thickness

Molten metal feed system controlled with a traveling magnetic field

Science.gov (United States)

Praeg, Walter F.

1991-01-01

A continuous metal casting system in which the feed of molten metal is controlled by means of a linear induction motor capable of producing a magnetic traveling wave in a duct that connects a reservoir of molten metal to a caster. The linear induction motor produces a traveling magnetic wave in the duct in opposition to the pressure exerted by the head of molten metal in the reservoir so that p.sub.c =p.sub.g -p.sub.m where p.sub.c is the desired pressure in the caster, p.sub.g is the gravitational pressure in the duct exerted by the force of the head of molten metal in the reservoir, and p.sub.m is the electromagnetic pressure exerted by the force of the magnetic field traveling wave produced by the linear induction motor. The invention also includes feedback loops to the linear induction motor to control the casting pressure in response to measured characteristics of the metal being cast.

Liquid metals. Coexistence line, critical parameters, compressibility

International Nuclear Information System (INIS)

Filippov, L.P.

1986-01-01

Formulae to calculate four characteristic parameters of liquid metals (density, compressibility, critical temperature and individual parameter) according to four initial data are obtained: two values of vapor density and two values of vapor pressure. Comparison between experimental and calculation results are presented for liquid Cs, Na, Li, K, Rb

Liquid-liquid contact in vapor explosion. [LMFBR

Energy Technology Data Exchange (ETDEWEB)

Segev, A.

1978-08-01

The contact of two liquid materials, one of which is at a temperature substantially above the boiling point of the other, can lead to fast energy conversion and a subsequent shock wave. This phenomenon is called a vapor explosion. One method of producing intimate, liquid-liquid contact (which is known to be a necessary condition for vapor explosion) is a shock tube configuration. Such experiments in which water was impacted upon molten aluminum showed that very high pressures, even larger than the thermodynamic critical pressure, could occur. The mechanism by which such sharp pressure pulses are generated is not yet clear. The report describes experiments in which cold liquids (Freon-11, Freon-22, water, or butanol) were impacted upon various hot materials (mineral oil, silicone oil, water, mercury, molten Wood's metal or molten salt mixture).

Induction of mouthpart deformities in chironomid larvae exposed to contaminated sediments

Energy Technology Data Exchange (ETDEWEB)

Di Veroli, Alessandra [Dipartimento di Biologia Cellulare e Ambientale, Universita degli Studi di Perugia, Via Elce Di Sotto, 06123 Perugia (Italy); Goretti, Enzo [Dipartimento di Biologia Cellulare e Ambientale, Universita degli Studi di Perugia, Via Elce Di Sotto, 06123 Perugia (Italy); Paumen, Miriam Leon; Kraak, Michiel H.S.; Admiraal, Wim [Department of Aquatic Ecology and Ecotoxicology, Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, Sciencepark 904, 1098 XH Amsterdam (Netherlands)

2012-07-15

The aim of the present study was to improve the cause-effect relationship between toxicant exposure and chironomid mouthpart deformities, by linking induction of mouthpart deformities to contaminated field sediments, metal mixtures and a mutagenic polycyclic aromatic compound metabolite (acridone). Mouthpart deformities in Chironomus riparius larvae were induced by both the heavy metal mixture and by acridone. A clear correlation between metal concentrations in the sediment and deformities incidence was only observed when the contaminated field sediments were left out of the analysis, probably because these natural sediments contained other toxic compounds, which could be responsible for a higher incidence of deformities than predicted by the measured metal concentrations only. The present study clearly improved the cause-effect relationship between toxicant exposure and the induction of mouthpart deformities. It is concluded that the incidence of mouthpart deformities may better reflect the potential toxicity of contaminated sediments than chemical analysis. - Highlights: Black-Right-Pointing-Pointer We tested the induction of deformities in C. riparius in laboratory toxicity experiments. Black-Right-Pointing-Pointer We used field sediments and spiked sediments with heavy metals and mutagenic PAC. Black-Right-Pointing-Pointer Mouthpart deformities were induced both by heavy metal mixtures and by acridone. Black-Right-Pointing-Pointer A correlation between metal concentrations in the sediment and deformities was found. Black-Right-Pointing-Pointer Mouthpart deformities better reflect the toxicity of sediments than chemical analysis. - Mouthpart deformities of Chironomus riparius larvae better reflect the toxicity of sediments than chemical analysis.

Liquid metal cooling of synchrotron optics

International Nuclear Information System (INIS)

Smither, R.K.

1993-01-01

The installation of insertion devices at existing synchrotron facilities around the world has stimulated the development of new ways to cool the optical elements in the associated x-ray beamlines. Argonne has been a leader in the development of liquid metal cooling for high heat load x-ray optics for the next generation of synchrotron facilities. The high thermal conductivity, high volume specific heat, low kinematic viscosity, and large working temperature range make liquid metals a very efficient heat transfer fluid. A wide range of liquid metals were considered in the initial phase of this work. The most promising liquid metal cooling fluid identified to date is liquid gallium, which appears to have all the desired properties and the fewest number of undesired features of the liquid metals examined. Besides the special features of liquid metals that make them good heat transfer fluids, the very low vapor pressure over a large working temperature range make liquid gallium an ideal cooling fluid for use in a high vacuum environment. A leak of the liquid gallium into the high vacuum and even into very high vacuum areas will not result in any detectable vapor pressure and may even improve the vacuum environment as the liquid gallium combines with any water vapor or oxygen present in the system. The practical use of a liquid metal for cooling silicon crystals and other high heat load applications depends on having a convenient and efficient delivery system. The requirements for a typical cooling system for a silicon crystal used in a monochromator are pumping speeds of 2 to 5 gpm (120 cc per sec to 600 cc per sec) at pressures up to 100 psi. No liquid metal pump with these capabilities was available commercially when this project was started, so it was necessary to develop a suitable pump in house

Resistorless Electronically Tunable Grounded Inductance Simulator Design

OpenAIRE

Herencsár, Norbert; Kartci, Aslihan

2017-01-01

A new realization of grounded lossless positive inductance simulator (PIS) using simple inverting voltage buffer and unity-gain current follower/inverter (CF±) is reported. Considering the input intrinsic resistance of CF± as useful active parameter, the proposed PIS can be considered as resistorless circuit and it only employs in total 16 Metal-Oxide-Semiconductor (MOS) transistors and a grounded capacitor. The resulting equivalent inductance value of the proposed simulator can be adjusted v...

Ultracentrifugation and inductively coupled plasma mass spectrometry for metal-protein equilibrium studies

Energy Technology Data Exchange (ETDEWEB)

Arnquist, Isaac J.; Holcombe, James A., E-mail: holcombe@mail.utexas.edu

2012-10-15

The coupling of separation by preparative ultracentrifugation and metal detection by inductively coupled plasma mass spectrometry (ICP-MS) has been explored for metal-protein equilibrium determinations. This study characterizes the stoichiometry as well as apparent (K{sub app}) and intrinsic (K{sub int}) binding affinities of the metal-protein association for a model protein. In particular, the affinity of Cu{sup 2+} for the high affinity binding site in bovine serum albumin (BSA) is determined. Once equilibrium is established between Cu{sup 2+} and BSA, preparative ultracentrifugation moves the metalloprotein away from the meniscus, leaving unbound equilibrium copper in the protein free solution. Since the initial (total) concentrations of purified BSA and Cu{sup 2+} can be determined, the free copper concentration at equilibrium can also be determined by taking a small aliquot above the sedimenting boundary for analysis using ICP-MS. This analysis allows for the determination of free Cu{sup 2+} ion, which is identical to the equilibrium concentration prior to ultracentrifugation. From these data K{sub app} and K{sub int} were determined at two different conditions, 100 mM Tris(hydroxymethyl)aminomethane (Tris) at pH 9.53 and pH 7.93. log K{sub app} values of 17.6 and 14.6 were determined at pH 9.53 and pH 7.93, respectively. Furthermore, pH-independent log K{sub int} values of - 1.43 and - 1.04 were determined at pH 9.53 and 7.93, respectively. While the log K{sub int} at pH 9.53 was in good agreement with literature values obtained from alternative methods, K{sub int} at pH 7.93 was about 2.5 Multiplication-Sign larger than previously reported. BSA undergoes a structural rearrangement between pH 7-9, and the generally accepted pH-dependency of protein tertiary structure may be responsible for the variations in the 'intrinsic' binding constant. The Cu-BSA binding affinity was also monitored in 100 mM Tris 0.1% sodium dodecyl sulfate (SDS) solution at p

An Induction Heating Method with Traveling Magnetic Field for Long Structure Metal

Science.gov (United States)

Sekine, Takamitsu; Tomita, Hideo; Obata, Shuji; Saito, Yukio

A novel dismantlable adhesion method for recycling operation of interior materials is proposed. This method is applied a high frequency induction heating and a thermoplastic adhesive. For an adhesion of interior material to long steel stud, a conventional spiral coil as like IH cooking heater gives inadequateness for uniform heating to the stud. Therefore, we have proposed an induction heating method with traveling magnetic field for perfect long structures bonding. In this paper, we describe on the new adhesion method using the 20kHz, three-phase 200V inverter and linear induction coil. From induction heating characteristics to thin steel plates and long studs, the method is cleared the usefulness for uniform heating to long structures.

Alkali metal for ultraviolet band-pass filter

Science.gov (United States)

Mardesich, Nick (Inventor); Fraschetti, George A. (Inventor); Mccann, Timothy A. (Inventor); Mayall, Sherwood D. (Inventor); Dunn, Donald E. (Inventor); Trauger, John T. (Inventor)

1993-01-01

An alkali metal filter having a layer of metallic bismuth deposited onto the alkali metal is provided. The metallic bismuth acts to stabilize the surface of the alkali metal to prevent substantial surface migration from occurring on the alkali metal, which may degrade optical characteristics of the filter. To this end, a layer of metallic bismuth is deposited by vapor deposition over the alkali metal to a depth of approximately 5 to 10 A. A complete alkali metal filter is described along with a method for fabricating the alkali metal filter.

Beryllium doped p-type GaN grown by metal-organic chemical vapor depostion

International Nuclear Information System (INIS)

Al-Tahtamouni, T.M.; Sedhain, A.; Lin, J.Y.; Jiang, H.X.

2010-01-01

The authors report on the growth of Be-doped p-type GaN epilayers by metal-organic chmical vapor deposition (MOCVD). The electrical and optical properties of the Be-doped GaN epilayers were studied by Hall-effect measurements and photoluminescence (PL) spectroscopy. The PL spectra of Be-doped GaN epilayers ethibited two emission lines at 3.36 and 2.71 eV, which were obsent in undoped epilayers. The transition at 3.36 eV was at 3.36 and 2.71eV, which were absent in undoped epilayers. The transition at 3.36 eV was assigned to the transition of free electrons to the neutral Be acceptor Be d eg.. The transition at 2.71 eV was assigned to the transition of electrons bound to deep level donors to the Be d eg. acceptors. Three independent measurements: (a) resistivity vs. temperature, (b) PL peak positions between Be doped and undoped GaN and (c) activation energy of 2.71 eV transition all indicate that the Be energy level is between 120 and 140 meV above the valence band. This is about 20-40 meV shallower than the Mg energy level (160 meV) in GaN. It is thus concluded that Be could be an excellent acceptor dopant in nitride materials. (authors).

Vapor pressure and enthalpy of vaporization of aliphatic propanediamines

International Nuclear Information System (INIS)

Verevkin, Sergey P.; Chernyak, Yury

2012-01-01

Highlights: ► We measured vapor pressure of four aliphatic 1,3-diamines. ► Vaporization enthalpies at 298 K were derived. ► We examined consistency of new and available data in the literature. ► A group-contribution method for prediction was developed. - Abstract: Vapor pressures of four aliphatic propanediamines including N-methyl-1,3-propanediamine (MPDA), N,N-dimethyl-1,3-propanediamine (DMPDA), N,N-diethyl-1,3-propanediamine (DEPDA) and N,N,N′,N′-tetramethyl-1,3-propanediamine (4MPDA) were measured using the transpiration method. The vapor pressures developed in this work and reported in the literature were used to derive molar enthalpy of vaporization values at the reference temperature 298.15 K. An internal consistency check of the enthalpy of vaporization was performed for the aliphatic propanediamines studied in this work. A group-contribution method was developed for the validation and prediction vaporization enthalpies of amines and diamines.

Supersonic induction plasma jet modeling

International Nuclear Information System (INIS)

Selezneva, S.E.; Boulos, M.I.

2001-01-01

Numerical simulations have been applied to study the argon plasma flow downstream of the induction plasma torch. It is shown that by means of the convergent-divergent nozzle adjustment and chamber pressure reduction, a supersonic plasma jet can be obtained. We investigate the supersonic and a more traditional subsonic plasma jets impinging onto a normal substrate. Comparing to the subsonic jet, the supersonic one is narrower and much faster. Near-substrate velocity and temperature boundary layers are thinner, so the heat flux near the stagnation point is higher in the supersonic jet. The supersonic plasma jet is characterized by the electron overpopulation and the domination of the recombination over the dissociation, resulting into the heating of the electron gas. Because of these processes, the supersonic induction plasma permits to separate spatially different functions (dissociation and ionization, transport and deposition) and to optimize each of them. The considered configuration can be advantageous in some industrial applications, such as plasma-assisted chemical vapor deposition of diamond and polymer-like films and in plasma spraying of nanoscaled powders

Continuous condensation device for vapors in the atmosphere

International Nuclear Information System (INIS)

Tricot, M.

1983-01-01

The continuous condensation device for vapors from the atmosphere is such those in which this atmosphere circulates in contact with a cold source involving the condensation of these vapors. It includes a thermoelectric module using the Peltier effect; the hot side is bonded to a heat sink and the cold side is in contact with an insulated condensation chamber in which flows the atmosphere charged with vapors to be condensated. The condensation chamber has a metallic structure through which a low voltage direct current is passed; this structure has small blades with holes, through which the condensate flows under gravity in the lower part of the chamber which have a hole to evacuate this liquid. The thermoelectric module comprises an assembly of thermocouples made of an array of alloy plates. The temperature inside the condensation chamber is maintained at just above 0 0 C. This device is used for the sampling of atmosphere water especially in the determination of tritium content of the atmosphere around nuclear installations [fr

Influence of the interface on growth rates in AlN/GaN short period superlattices via metal organic vapor phase epitaxy

Science.gov (United States)

Rodak, L. E.; Korakakis, D.

2011-11-01

AlN/GaN short period superlattices are well suited for a number of applications including, but not limited to, digital alloys, intersubband devices, and emitters. In this work, AlN/GaN superlattices with periodicities ranging from 10 to 20 Å have been grown via metal organic vapor phase epitaxy in order to investigate the influence of the interface on the binary alloy growth rates. The GaN growth rate at the interface was observed to decrease with increasing GaN thickness while the AlN growth rate remained constant. This has been attributed to a decrease in the decomposition rate of GaN at the hetero-interface as seen in other III-V hetero-structures.

Molten metal feed system controlled with a traveling magnetic field

International Nuclear Information System (INIS)

Praeg, W.F.

1991-01-01

This patent describes a continuous metal casting system in which the feed of molten metal controlled by means of a linear induction motor capable of producing a magnetic traveling wave in a duct that connects a reservoir of molten metal to a caster. The linear induction motor produces a traveling magnetic wave in the duct in opposition to the pressure exerted by the head of molten metal in the reservoir

Vapor pressure and enthalpy of vaporization of linear aliphatic alkanediamines

International Nuclear Information System (INIS)

Pozdeev, Vasiliy A.; Verevkin, Sergey P.

2011-01-01

Highlights: → We measured vapor pressure of diamines H 2 N-(CH 2 ) n -NH 2 with n = 3 to 12. → Vaporization enthalpies at 298 K were derived. → We examined consistency of new and available in the literature data. → Enthalpies of vaporization show linear dependence on numbers n. → Enthalpies of vaporization correlate linearly with Kovat's indices. - Abstract: Vapor pressures and the molar enthalpies of vaporization of the linear aliphatic alkanediamines H 2 N-(CH 2 ) n -NH 2 with n = (3 to 12) have been determined using the transpiration method. A linear correlation of enthalpies of vaporization (at T = 298.15 K) of the alkanediamines with the number n and with the Kovat's indices has been found, proving the internal consistency of the measured data.

Development of the methodology for the MHD analysis in a linear induction electro-magnetic pump

International Nuclear Information System (INIS)

Seong, Seung Hwan; Hur, Seop; Kim, Seong O; Choi, Seok Ki; Wi, Myung Hwan; Jeon, Won Dae

2004-01-01

Generally, fast breeder reactors have adopted a liquid metal as a coolant for the heat transfer from the reactor to the heat exchangers. Since a liquid metal has an electrical conductivity, the pumping of the liquid metal may use an induction electro-magnetic (EM) pump which induces electrical current and body force on the metal flow. These linear induction pumps use a traveling magnetic field wave created by poly-phase currents and the induced currents and their associated magnetic field generate the Lorentz force whose effect can be actually the pumping of the liquid metal. The flow behaviors in the pump are very complex such as the existence of a rotational force, pulsation and so on, because the induction EM pump has time-varying magnetic fields and the induced convective currents which originate form the flow of the liquid metal. These phenomena generate a stability problem in the pump and depend on the changes of the magnetic field and fluid flow field due to the induced currents and the fluid flow of the liquid metal with time and complex pump geometry. Therefore, an exact flow analysis is required for designing and evaluating the stability of a pump

Leaching of heavy metals from contaminated soils using inductively coupled plasma optical emission spectrometer (ICP-OES) and atomic absorption spectrometer (AAS)

International Nuclear Information System (INIS)

Hussain, Z.; Islam, M.

2010-01-01

The clean-up of soils contaminated with heavy metals is one of the most difficult tasks for environmental engineering. Heavy metals are highly persistent in soil and a number of techniques have been developed that aim to remove heavy metals from contaminated soil. A method has been adopted to evaluate dynamic leaching of metal contaminants from industrial soil samples obtained from textile industrial sites in Lahore, Pakistan. In the extraction procedures employed five different leaching liquors were used: 0.01 M CaCl/sub 2/, 1 M HNO/sub 3/, a 1:1 mixture of 0.1M HCl and 0.1M NaCl, 0.01 M EDTA and pH controlled 0.5 M acetic acid. The qualitative and quantitative analyses were carried out by Atomic Absorption Spectroscopy (AAS) and Inductively Coupled Plasma-Optical Emission Spectrometer (ICP-OES). The results indicate that Cu, Zn, Cd, Ni, Pb, Fe and As were extracted in the soil samples in varying concentration when using the different leach liquors. The predominant metals which were leached were As 78.7 ng/ml in 0.01 M EDTA; Zn 1.81 mu g/ml and Fe 898.96 macro g/ml in HNO/sub 3/. (author)

Study of film boiling collapse behavior during vapor explosion

International Nuclear Information System (INIS)

Yagi, Masahiro; Yamano, Norihiro; Sugimoto, Jun; Abe, Yutaka; Adachi, Hiromichi; Kobayashi, Tomoyoshi.

1996-06-01

Possible large scale vapor explosions are safety concern in nuclear power plants during severe accident. In order to identify the occurrence of the vapor explosion and to estimate the magnitude of the induced pressure pulse, it is necessary to investigate the triggering condition for the vapor explosion. As a first step of this study, scooping analysis was conducted with a simulation code based on thermal detonation model. It was found that the pressure at the collapse of film boiling much affects the trigger condition of vapor explosion. Based on this analytical results, basic experiments were conducted to clarify the collapse conditions of film boiling on a high temperature solid ball surface. Film boiling condition was established by flooding water onto a high temperature stainless steel ball heated by a high frequency induction heater. After the film boiling was established, the pressure pulse generated by a shock tube was applied to collapse the steam film on the ball surface. As the experimental boundary conditions, materials and size of the balls, magnitude of pressure pulse and initial temperature of the carbon and stainless steel balls were varied. The transients of pressure and surface temperature were measured. It was found that the surface temperature on the balls sharply decreased when the pressure wave passed through the film on balls. Based on the surface temperature behavior, the film boiling collapse pattern was found to be categorized into several types. Especially, the pattern for stainless steel ball was categorized into three types; no collapse, collapse and reestablishment after collapse. It was thus clarified that the film boiling collapse behavior was identified by initial conditions and that the pressure required to collapse film boiling strongly depended on the initial surface temperature. The present results will provide a useful information for the analysis of vapor explosions based on the thermal detonation model. (J.P.N.)

The influence of water vapor and sulfur dioxide on the catalytic decomposition of nitrous oxide

Energy Technology Data Exchange (ETDEWEB)

Yalamas, C.; Heinisch, R.; Barz, M. [Technische Univ. Berlin (Germany). Inst. fuer Energietechnik; Cournil, M. [Ecole Nationale Superieure des Mines, 42 - Saint-Etienne (France)

2001-03-01

For the nitrous oxide decomposition three groups of catalysts such as metals on support, hydrotalcites, and perovskites were studied relating to their activity in the presence of vapor or sulfur dioxide, in the temperature range from 200 to 500 C. It was found that the water vapor strongly inhibates the nitrous oxide decomposition at T=200-400 C. The sulfur dioxide poisons the catalysts, in particular the perovskites. (orig.)

PROCESS FOR PREPARING URANIUM METAL

Science.gov (United States)

Prescott, C.H. Jr.; Reynolds, F.L.

1959-01-13

A process is presented for producing oxygen-free uranium metal comprising contacting iodine vapor with crude uranium in a reaction zone maintained at 400 to 800 C to produce a vaporous mixture of UI/sub 4/ and iodine. Also disposed within the maction zone is a tungsten filament which is heated to about 1600 C. The UI/sub 4/, upon contacting the hot filament, is decomposed to molten uranium substantially free of oxygen.

Metal-halide lamp design: atomic and molecular data needed

International Nuclear Information System (INIS)

Lapatovich, Walter P

2009-01-01

Metal-halide lamps are a subset of high intensity discharge (HID) lamps so named because of their high radiance. These lamps are low temperature (∼0.5 eV), weakly ionized plasmas sustained in refractory but light transmissive envelopes by the passage of electric current through atomic and molecular vapors. For commercial applications, the conversion of electric power to light must occur with good efficiency and with sufficient spectral content throughout the visible (380-780 nm) to permit the light so generated to render colors comparable to natural sunlight. This is achieved by adding multiple metals to a basic mercury discharge. Because the vapor pressure of most metals is very much lower than mercury itself, metal-halide salts of the desired metals, having higher vapor pressures, are used to introduce the material into the basic discharge. The metal compounds are usually polyatomic iodides, which vaporize and subsequently dissociate as they diffuse into the bulk plasma. Metals with multiple visible transitions are necessary to achieve high photometric efficiency (efficacy) and good color. Compounds of Sc, Dy, Ho, Tm, Ce, Pr, Yb and Nd are commonly used. The electrons, atoms and radicals are in local thermodynamic equilibrium (LTE), but not with the radiation field. Strong thermal (10 6 K m -1 ) and density gradients are sustained in the discharge. Atomic radiation produced in the high-temperature core transits through colder gas regions where it interacts with cold atoms and un-dissociated molecules before exiting the lamp. Power balance and spectral output of the lamp are directly affected by the strength of atomic transitions. Attempts to simulate the radiative output of functional metal-halide lamps have been successful only in very simple cases. More data (e.g. the atomic transition probabilities of Ce i) are necessary to improve lamp performance, to select appropriate radiators and in scaling the lamp geometry to various wattages for specific applications.

New approaches to the study of lanthanide/actinide chloride: aluminum chloride vapor phase complexes

International Nuclear Information System (INIS)

Peterson, E.J.; Caird, J.A.; Carnall, W.T.; Hessler, J.P.; Hoekstra, H.R.; Williams, C.W.

1979-01-01

The spectrophotometric technique for vapor density measurements of complexed metal ions has been reformulated to account for temperature dependent effects and multi-species systems. Analysis of vapor pressure information indicates that the NdCl 3 --AlCl 3 and HoCl 3 --AlCl 3 systems are adequately explained by the existence of three vapor species. The two higher molecular weight complexes LnAl 4 Cl 15 and LnAl 3 Cl 12 were first proposed by Oeye and Gruen. The newly identified higher temperature species, HoAl 2 Cl 9 , contributes significantly to the vapor density above 750 0 K and below 3 atm of dimer pressure. In view of the consistency of the Nd +3 and Ho +3 chemistry the data for the Sm +3 system should be viewed with reservation. A new method for vapor density measurements involving use of radioactive tracers has been discussed in terms of its applicability to the study of (Ln,An)Cl 3 (AlCl 3 )/sub x/ systems

Generalized modeling of multi-component vaporization/condensation phenomena for multi-phase-flow analysis

International Nuclear Information System (INIS)

Morita, K.; Fukuda, K.; Tobita, Y.; Kondo, Sa.; Suzuki, T.; Maschek, W.

2003-01-01

A new multi-component vaporization/condensation (V/C) model was developed to provide a generalized model for safety analysis codes of liquid metal cooled reactors (LMRs). These codes simulate thermal-hydraulic phenomena of multi-phase, multi-component flows, which is essential to investigate core disruptive accidents of LMRs such as fast breeder reactors and accelerator driven systems. The developed model characterizes the V/C processes associated with phase transition by employing heat transfer and mass-diffusion limited models for analyses of relatively short-time-scale multi-phase, multi-component hydraulic problems, among which vaporization and condensation, or simultaneous heat and mass transfer, play an important role. The heat transfer limited model describes the non-equilibrium phase transition processes occurring at interfaces, while the mass-diffusion limited model is employed to represent effects of non-condensable gases and multi-component mixture on V/C processes. Verification of the model and method employed in the multi-component V/C model of a multi-phase flow code was performed successfully by analyzing a series of multi-bubble condensation experiments. The applicability of the model to the accident analysis of LMRs is also discussed by comparison between steam and metallic vapor systems. (orig.)

Thermohydraulic behavior of liquid metal pool submitted to electronic bombardment

International Nuclear Information System (INIS)

Brun, Patrice

1998-01-01

This thesis deals with the thermohydraulics of liquid metal molten by an electron beam. We study the relationship between the liquid metal pool and the vapor rate. The aim is to find good conditions increasing the metal vapor rate. In first place, energy losses are identified. Mains are convection (buoyancy and thermo-capillary) strengthen by the deformation of the molten pool. The first action is to reduce the liquid interface deformation with a transient spot realized by scanning the electron beam. I find that in this case, the optimum vapor rate is obtained when the crossing time of the beam is smaller than characteristic time of formation of the cavity, but greater than the heating time of the surface. Secondly, I impose forces to change the morphology of the flow. Two actions are tried: magnetic field application and rotating motion of the crucible. External magnetic field application may reduce convective flow, by the creation of a magnetic brake. But in my experiment, magnetic field deteriorates electron beam before to be effective. Results obtained by the rotating motion of the crucible approve this choice to reduce energy losses and increase vapor rate. This growth of vapor rate is due to an expansion of the emitted vapor source and an increase of the central temperature of the molten pool. Nevertheless with the increase of the rotation velocity and after the optimum vapor rate, I note that the flow is not axisymmetric. My observation give to think about instabilities that are developed by baroclinic waves. The comparison of my works with the Eady's linear theory gives good results. (author) [fr

Study of TiO{sub 2} nanomembranes obtained by an induction heated MOCVD reactor

Energy Technology Data Exchange (ETDEWEB)

Crisbasan, A., E-mail: andreea.crisbasan@yahoo.com [NANOFORM Group, ICB, Université de Bourgogne, BP 47 870, 21078 Dijon (France); Chaumont, D. [NANOFORM Group, ICB, Université de Bourgogne, BP 47 870, 21078 Dijon (France); Sacilotti, M. [NANOFORM Group, ICB, Université de Bourgogne, BP 47 870, 21078 Dijon (France); Departamento de Fisica – Universidade Federal de Pernambuco, Recife (Brazil); Crisan, A.; Lazar, A.M.; Ciobanu, I. [Science and Materials Engineering Faculty, University of Transilvania, Brasov (Romania); Lacroute, Y.; Chassagnon, R. [Université de Bourgogne, BP 47 870, 21078 Dijon (France)

2015-12-15

Highlights: • The TiO{sub 2} structures have been obtained by the MOCVD technique using ferrocene, cobalt layer (annealed at 350 °C) and Ti(OC{sub 3}H{sub 7}){sub 4}. • The TiO{sub 2} growth at 550 °C, during 20 min on the cobalt layer (obtained by electron beam evaporation method) on soda-lime glass has as result TiO{sub 2} nanomembranes. • The TiO{sub 2} nanomembranes grow on the cobalt nuclei. • The TiO{sub 2} nanomembranes are polycrystalline, built from TiO{sub 2} anatase and rutile crystals. - Abstract: Nanostructures of TiO{sub 2} were grown using the metal oxide chemical vapor deposition (MOCVD) technique. The procedure used induction heating on a graphite susceptor. This specific feature and the use of cobalt and ferrocene catalysts resulted in nanomembranes never obtained by common MOCVD reactors. The present study discusses the preparation of TiO{sub 2} nanomembranes and the dependence of nanomembrane structure and morphology on growth parameters.

Radioactive scrap metal decontamination technology assessment report

International Nuclear Information System (INIS)

Buckentin, J.M.; Damkroger, B.K.; Schlienger, M.E.

1996-04-01

Within the DOE complex there exists a tremendous quantity of radioactive scrap metal. As an example, it is estimated that within the gaseous diffusion plants there exists in excess of 700,000 tons of contaminated stainless steel. At present, valuable material is being disposed of when it could be converted into a high quality product. Liquid metal processing represents a true recycling opportunity for this material. By applying the primary production processes towards the material's decontamination and re-use, the value of the strategic resource is maintained while drastically reducing the volume of material in need of burial. Potential processes for the liquid metal decontamination of radioactively contaminated metal are discussed and contrasted. Opportunities and technology development issues are identified and discussed. The processes compared are: surface decontamination; size reduction, packaging and burial; melting technologies; electric arc melting; plasma arc centrifugal treatment; air induction melting; vacuum induction melting; and vacuum induction melting and electroslag remelting

Induction brazing of complex joints

DEFF Research Database (Denmark)

Henningsen, Poul; Zhang, Wenqi; Bay, Niels

2003-01-01

, or if the hottest area is located outside the joint interface, a number of defects may appear: the braze metal may flow away from the joint, the flux may burn off, poor binding of the braze metal may appear or the braze metal may be overheated. Joint geometry as well as electro-magnetic properties of the work piece...... presents a combined numerical and experimental method for fast determination of appropriate coil geometry and position in induction brazing tube-to-plate joints of different ratios between tube and plate thickness and different combinations of the materials stainless steel, brass and copper. The method has...... proven to give successful results in brazing tube-plate joints of copper-brass, copper-stainless steel, stainless steel-brass, and stainless steel-stainless steel....

Volatilization of heavy metals and radionuclides from soil heated in an induction ''cold'' crucible melter

International Nuclear Information System (INIS)

Aloy, A.S.; Belov, V.Z.; Trofimenko, A.S.; Dmitriev, S.A.; Stefanovsky, S.V.; Gombert, D.; Knecht, D.A.

1997-01-01

The behavior of heavy metals and radionuclides during high-temperature treatment is very important for the design and operational capabilities of the off-gas treatment system, as well as for a better understanding of the nature and forms of the secondary waste. In Russia, a process for high-temperature melting in an induction heated cold crucible system is being studied for vitrification of Low Level Waste (LLW) flyash and SYNROC production with simulated high level waste (HLW). This work was done as part of a Department of Energy (DOE) funded research project for thermal treatment of mixed low level waste (LLW). Soil spiked with heavy metals (Cd, Pb) and radionuclides (Cs-137, U-239, Pu-239) was used as a waste surrogate. The soil was melted in an experimental lab-scale system that consisted of a high-frequency generator (1.76 MHz, 60 kW), a cold crucible melter (300 mm high and 90 mm in diameter), a shield box, and an off-gas system. The process temperature was 1,350--1,400 C. Graphite and silicon carbide were used as sacrificial conductive materials to start heating and initial melting of the soil batch. The off-gas system was designed in such a manner that after each experiment, it can be disconnected to collect and analyze all deposits to determine the mass balance. The off-gases were also sampled during an experiment to analyze for hydrogen, NO x , carbon dioxide, carbon monoxide and chlorine formation. This paper describes distribution and mass balance of metals and radionuclides in various parts of the off-gas system. The leach rate of the solidified blocks identified by the PCT method is also reported

Thermo-hydrodynamic and inductive modelling of a glass melt elaborated in cold inductive crucible

International Nuclear Information System (INIS)

Sauvage, E.

2009-11-01

Within the context of a search for a new vitrification process for nuclear wastes with a replacement of the presently used metallic pot by an inductive cold crucible, this research thesis deals with the numerical modelling of this technology. After having recalled the interest of nuclear waste vitrification, this report presents the new process based on the use of a cold crucible, describing principles and objectives of this method, and the characteristic physical phenomena associated with the flow and the thermodynamics of the glassy melt in such a crucible. It also recalls and comments the existing works on modelling. The main objective of this research is then to demonstrate the feasibility of 3D thermo-hydraulic and inductive simulations. He describes and analyses the glass physical properties (electrical properties, viscosity, thermal properties), the electromagnetic, hydrodynamic and thermal phenomena. He presents in detail the bubbling mixing modelling, reports 3D induction and fluid mechanical coupling calculations, and specific thermal investigations (radiating transfers, thermal limit conditions)

VAPOR PRESSURES AND HEATS OF VAPORIZATION OF PRIMARY COAL TARS

Energy Technology Data Exchange (ETDEWEB)

Eric M. Suuberg; Vahur Oja

1997-07-01

This project had as its main focus the determination of vapor pressures of coal pyrolysis tars. It involved performing measurements of these vapor pressures and from them, developing vapor pressure correlations suitable for use in advanced pyrolysis models (those models which explicitly account for mass transport limitations). This report is divided into five main chapters. Each chapter is a relatively stand-alone section. Chapter A reviews the general nature of coal tars and gives a summary of existing vapor pressure correlations for coal tars and model compounds. Chapter B summarizes the main experimental approaches for coal tar preparation and characterization which have been used throughout the project. Chapter C is concerned with the selection of the model compounds for coal pyrolysis tars and reviews the data available to us on the vapor pressures of high boiling point aromatic compounds. This chapter also deals with the question of identifying factors that govern the vapor pressures of coal tar model materials and their mixtures. Chapter D covers the vapor pressures and heats of vaporization of primary cellulose tars. Chapter E discusses the results of the main focus of this study. In summary, this work provides improved understanding of the volatility of coal and cellulose pyrolysis tars. It has resulted in new experimentally verified vapor pressure correlations for use in pyrolysis models. Further research on this topic should aim at developing general vapor pressure correlations for all coal tars, based on their molecular weight together with certain specific chemical characteristics i.e. hydroxyl group content.

The growth of mid-infrared emitting InAsSb/InAsP strained-layer superlattices using metal-organic chemical vapor deposition

International Nuclear Information System (INIS)

Biefeld, R.M.; Allerman, A.A.; Kurtz, S.R.; Burkhart, J.H.

1997-01-01

We describe the metal-organic chemical vapor deposition os InAsSb/InAsP strained-layer superlattice (SLS) active regions for use in mid-infrared emitters. These SLSs were grown at 500 degrees C, and 200 torr in a horizontal quartz reactor using trimethylindium, triethylantimony, AsH 3 , and PH 3 . By changing the layer thickness and composition we have prepared structures with low temperature (≤20K) photoluminescence wavelengths ranging from 3.2 to 5.0 μm. Excellent performance was observed for an SLS light emitting diode (LED) and both optically pumped and electrically injected SLS layers. An InAsSb/InAsP SLS injection laser emitted at 3.3 μm at 80 K with peak power of 100 mW

Removal of toxic and alkali/alkaline earth metals during co-thermal treatment of two types of MSWI fly ashes in China.

Science.gov (United States)

Yu, Jie; Qiao, Yu; Jin, Limei; Ma, Chuan; Paterson, Nigel; Sun, Lushi

2015-12-01

This study aims to vaporize heavy metals and alkali/alkaline earth metals from two different types of fly ashes by thermal treatment method. Fly ash from a fluidized bed incinerator (HK fly ash) was mixed with one from a grate incinerator (HS fly ash) in various proportions and thermally treated under different temperatures. The melting of HS fly ash was avoided when treated with HK fly ash. Alkali/alkaline earth metals in HS fly ash served as Cl-donors to promote the vaporization of heavy metals during thermal treatment. With temperature increasing from 800 to 900°C, significant amounts of Cl, Na and K were vaporized. Up to 1000°C in air, less than 3% of Cl and Na and less than 5% of K were retained in ash. Under all conditions, Cd can be vaporized effectively. The vaporization of Pb was mildly improved when treated with HS fly ash, while the effect became less pronounced above 900°C. Alkali/alkaline earth metals can promote Cu vaporization by forming copper chlorides. Comparatively, Zn vaporization was low and only slightly improved by HS fly ash. The low vaporization of Zn could be caused by the formation of Zn2SiO4, ZnFe2O4 and ZnAl2O4. Under all conditions, less than 20% of Cr was vaporized. In a reductive atmosphere, the vaporization of Cd and Pb were as high as that in oxidative atmosphere. However, the vaporization of Zn was accelerated and that of Cu was hindered because the formation of Zn2SiO4, ZnFe2O4 and ZnAl2O4 and copper chloride was depressed in reductive atmosphere. Copyright © 2015. Published by Elsevier Ltd.

Characterization of Pb(Zr, Ti)O sub 3 thin films prepared by metal-organic chemical-vapor deposition using a solid delivery system

CERN Document Server

Shin, J C; Hwang, C S; Kim, H J; Lee, J M

1999-01-01

Pb(Zr, Ti)O sub 3 (PZT) thin films were deposited on Pt/SiO sub 2 /Si substrates by metal-organic chemical-vapor deposition technique using a solid delivery system to improve the reproducibility of the deposition. The self-regulation mechanism, controlling the Pb-content of the film, was observed to work above a substrate temperature of 620 .deg. C. Even with the self-regulation mechanism, PZT films having low leakage current were obtained only when the molar mixing ratio of the input precursors was 1

Formation and characterization of the MgO protecting layer deposited by plasma-enhanced metal-organic chemical-vapor deposition

CERN Document Server

Kang, M S; Byun, J C; Kim, D S; Choi, C K; Lee, J Y; Kim, K H

1999-01-01

MgO films were prepared on Si(100) and soda-lime glass substrates by using plasma-enhanced metal-organic chemical-vapor deposition. Various ratios of the O sub 2 /CH sub 3 MgO sup t Bu gas mixture and various gas flow rates were tested for the film fabrications. Highly (100)-oriented MgO films with good crystallinity were obtained with a 10 sccm CH sub 3 MgO sup t Bu flow without an O sub 2 gas flow. About 5 % carbon was contained in all the MgO films. The refractive index and the secondary electron emission coefficient for the best quality film were 1.43 and 0.45, respectively. The sputtering rate was about 0.2 nm/min for 10 sup 1 sup 1 cm sup - sup 3 Ar sup + ion density. Annealing at 500 .deg. C in an Ar ambient promoted the grain size without inducing a phase transition.

Effect of Water Vapor and Surface Morphology on the Low Temperature Response of Metal Oxide Semiconductor Gas Sensors

Directory of Open Access Journals (Sweden)

Konrad Maier

2015-09-01

Full Text Available In this work the low temperature response of metal oxide semiconductor gas sensors is analyzed. Important characteristics of this low-temperature response are a pronounced selectivity to acid- and base-forming gases and a large disparity of response and recovery time constants which often leads to an integrator-type of gas response. We show that this kind of sensor performance is related to the trend of semiconductor gas sensors to adsorb water vapor in multi-layer form and that this ability is sensitively influenced by the surface morphology. In particular we show that surface roughness in the nanometer range enhances desorption of water from multi-layer adsorbates, enabling them to respond more swiftly to changes in the ambient humidity. Further experiments reveal that reactive gases, such as NO2 and NH3, which are easily absorbed in the water adsorbate layers, are more easily exchanged across the liquid/air interface when the humidity in the ambient air is high.

Laser induced explosive vapor and cavitation resulting in effective irrigation of the root canal. Part 1: a visualization study

NARCIS (Netherlands)

Blanken, J.; de Moor, R.J.G.; Meire, M.; Verdaasdonk, R.

2009-01-01

Background and Objectives: Limited information exists regarding the induction of explosive vapor and cavitation bubbles in an endodontic rinsing solution. It is also not clear whether a fiber has to be moved in the irrigation solution or can be kept stationary. No information is available on safe

Laser Induced Explosive Vapor and Cavitation Resulting in Effective Irrigation of the Root Canal. Part 1 : A Visualization Study

NARCIS (Netherlands)

Blanken, Jan; De Moor, Roeland Jozef Gentil; Meire, Maarten; Verdaasdonk, Rudolf

Background and Objectives: Limited information exists regarding the induction of explosive vapor and cavitation bubbles in an endodontic rinsing solution. It is also not clear whether a fiber has to be moved in the irrigation solution or can be kept stationary. No information is available on safe

A Tightly Coupled Non-Equilibrium Magneto-Hydrodynamic Model for Inductively Coupled RF Plasmas

Science.gov (United States)

2016-02-29

development a tightly coupled magneto-hydrodynamic model for Inductively Coupled Radio- Frequency (RF) Plasmas. Non Local Thermodynamic Equilibrium (NLTE...for Inductively Coupled Radio-Frequency (RF) Plasmas. Non Local Thermodynamic Equilibrium (NLTE) effects are described based on a hybrid State-to-State...Inductively Coupled Plasma (ICP) torches have wide range of possible applications which include deposition of metal coatings, synthesis of ultra-fine powders

Enthalpy of Vaporization and Vapor Pressures: An Inexpensive Apparatus

Science.gov (United States)

Battino, Rubin; Dolson, David A.; Hall, Michael A.; Letcher, Trevor M.

2007-01-01

A simple and inexpensive method to determine the enthalpy of vaporization of liquids by measuring vapor pressure as a function of temperature is described. The vapor pressures measured with the stopcock cell were higher than the literature values and those measured with the sidearm rubber septum cell were both higher and lower than literature…

Observations of Metallic Species in Mercury's Exosphere

Science.gov (United States)

Killen, Rosemary M.; Potter, Andrew E.; Vervack, Ronald J., Jr.; Bradley, E. Todd; McClintock, William E.; Anderson, Carrie M.; Burger, Matthew H.

2010-01-01

From observations of the metallic species sodium (Na), potassium (K), and magnesium (Mg) in Mercury's exosphere, we derive implications for source and loss processes. All metallic species observed exhibit a distribution and/or line width characteristic of high to extreme temperature - tens of thousands of degrees K. The temperatures of refractory species, including magnesium and calcium, indicate that the source process for the atoms observed in the tail and near-planet exosphere are consistent with ion sputtering and/or impact vaporization of a molecule with subsequent dissociation into the atomic form. The extended Mg tail is consistent with a surface abundance of 5-8% Mg by number, if 30% of impact-vaporized Mg remains as MgO and half of the impact vapor condenses. Globally, ion sputtering is not a major source of Mg, but locally the sputtered source can be larger than the impact vapor source. We conclude that the Na and K in Mercury's exosphere can be derived from a regolith composition similar to that of Luna 16 soil (or Apollo 17 orange glass), in which the abundance by number is 0.0027 (0.0028) for Na and 0.0006 (0.0045) for K.

Separating and recycling metals from mixed metallic particles of crushed electronic wastes by vacuum metallurgy.

Science.gov (United States)

Zhan, Lu; Xu, Zhenming

2009-09-15

During the treatment of electronic wastes, a crushing process is usually used to strip metals from various base plates. Several methods have been applied to separate metals from nonmetals. However, mixed metallic particles obtained from these processes are still a mixture of various metals, including some toxic heavy metals such as lead and cadmium. With emphasis on recovering copper and other precious metals, there have hitherto been no satisfactory methods to recover these toxic metals. In this paper, the criterion of separating metals from mixed metallic particles by vacuum metallurgy is built. The results show that the metals with high vapor pressure have been almost recovered completely, leading to a considerable reduction of environmental pollution. In addition, the purity of copper in mixed particles has been improved from about 80 wt % to over 98 wt %.

Vapor pressures and vaporization enthalpy of codlemone by correlation gas chromatography

International Nuclear Information System (INIS)

Schultz, Shannon M.; Harris, Harold H.; Chickos, James S.

2015-01-01

Highlights: • The vaporization enthalpy of codlemone has been evaluated. • The vapor pressure of codlemone has been evaluated from T = (298.15 to T b ) K. • Vapor pressures for the 1-alkanols standards are available from T = (298.15 to 500) K. - Abstract: The vapor pressure and vaporization enthalpy of codlemone (trans, trans 8,10-dodecadien-1-ol), the female sex hormone of the codling moth is evaluated by correlation gas chromatography using a series of saturated primary alcohols as standards. A vaporization enthalpy of (92.3 ± 2.6) kJ · mol −1 and a vapor pressure, p/Pa = (0.083 ± 0.012) were evaluated at T = 298.15 K. An equation for the evaluation of vapor pressure from ambient temperature to boiling has been derived by correlation for codlemone. The calculated boiling temperature of T B = 389 K at p = 267 Pa is within the temperature range reported in the literature. A normal boiling temperature of T B = (549.1 ± 0.1) K is also estimated by extrapolation

Volcanic Metal Emissions and Implications for Geochemical Cycling and Mineralization

Science.gov (United States)

Edmonds, M.; Mather, T. A.

2016-12-01

Volcanoes emit substantial fluxes of metals to the atmosphere in volcanic gas plumes in the form of aerosol, adsorbed onto silicate particles and even in some cases as gases.. A huge database of metal emissions has been built over the preceding decades, which shows that volcanoes emit highly volatile metals into the atmosphere, such as As, Bi, Cd, Hg, Re, Se, Tl, among others. Understanding the cycling of metals through the Solid Earth system has importance for tackling a wide range of Earth Science problems, e.g. (1) the environmental impacts of metal emissions; (2) the sulfur and metal emissions of volcanic eruptions; (3) the behavior of metals during subduction and slab devolatilization; (4) the influence of redox on metal behavior in subduction zones; (5) the partitioning of metals between magmatic vapor, brines and melts; and (6) the relationships between volcanism and ore deposit formation. It is clear, when comparing the metal composition and flux in the gases and aerosols emitted from volcanoes, that they vary with tectonic setting. These differences allow insights into how the magmatic vapor was generated and how it interacted with melts and sulfides during magma differentiation and decompression. Hotspot volcanoes (e.g. Kilauea, Hawaii; volcanoes in Iceland) outgas a metal suite that mirrors the sulfide liquid-silicate melt partitioning behaviors reconstructed from experiments (as far as they are known), suggesting that the aqueous fluids (that will later be outgassed from the volcano) receive metals directly from oxidation of sulfide liquids during degassing and ascent of magmas towards the surface. At arc volcanoes, the gaseous fluxes of metals are typically much higher; and there are greater enrichments in elements that partition strongly into vapor or brine from silicate melts such as Cu, Au, Zn, Pb, W. We collate and present data on volcanic metal emissions from volcanoes worldwide and review the implications of the data array for metal cycling

Selective epitaxial growth of Ge1-xSnx on Si by using metal-organic chemical vapor deposition

Science.gov (United States)

Washizu, Tomoya; Ike, Shinichi; Inuzuka, Yuki; Takeuchi, Wakana; Nakatsuka, Osamu; Zaima, Shigeaki

2017-06-01

Selective epitaxial growth of Ge and Ge1-xSnx layers on Si substrates was performed by using metal-organic chemical vapor deposition (MOCVD) with precursors of tertiary-butyl-germane (t-BGe) and tri-butyl-vinyl-tin (TBVSn). We investigated the effects of growth temperature and total pressure during growth on the selectivity and the crystallinity of the Ge and Ge1-xSnx epitaxial layers. Under low total pressure growth conditions, the dominant mechanism of the selective growth of Ge epitaxial layers is the desorption of the Ge precursors. At a high total pressure case, it is needed to control the surface migration of precursors to realize the selectivity because the desorption of Ge precursors was suppressed. The selectivity of Ge growth was improved by diffusion of the Ge precursors on the SiO2 surfaces when patterned substrates were used at a high total pressure. The selective epitaxial growth of Ge1-xSnx layer was also realized using MOCVD. We found that the Sn precursors less likely to desorb from the SiO2 surfaces than the Ge precursors.

Effect of the substrate on the properties of ZnO-MgO thin films grown by atmospheric pressure metal-organic chemical vapor deposition

Energy Technology Data Exchange (ETDEWEB)

Torres-Huerta, A.M., E-mail: atohuer@hotmail.com [Instituto Politecnico Nacional, Grupo de Ingenieria en Procesamiento de Materiales CICATA-IPN, Unidad Altamira, km 14.5, Carretera Tampico-Puerto Industrial Altamira. C. P. 89600, Altamira, Tamps (Mexico); Dominguez-Crespo, M.A. [Instituto Politecnico Nacional, Grupo de Ingenieria en Procesamiento de Materiales CICATA-IPN, Unidad Altamira, km 14.5, Carretera Tampico-Puerto Industrial Altamira. C. P. 89600, Altamira, Tamps (Mexico); Brachetti-Sibaja, S.B. [Alumna del postgrado en Tecnologia Avanzada del CICATA-IPN, Unidad Altamira IPN, km 14.5, Carretera Tampico-Puerto Industrial Altamira. C. P. 89600, Altamira, Tamps (Mexico); Arenas-Alatorre, J. [Instituto de Fisica, UNAM, Apartado Postal 20-364, 01000, D.F. (Mexico); Rodriguez-Pulido, A. [Unidad Profesional Adolfo Lopez Mateos, Luis Enrique Erro s/n, 07738, D. F. (Mexico)

2011-07-01

The ZnO-MgO alloys possess attractive properties for possible applications in optoelectronic and display devices; however, the optical properties are strongly dependent on the deposition parameters. In this work, the effect of the glassy and metallic substrates on the structural, morphological and optical properties of ZnO-MgO thin films using atmospheric pressure metal-organic chemical vapor deposition was investigated at relatively low deposition temperature, 500 deg. C. Magnesium and zinc acetylacetonates were used as the metal-organic source. X-ray diffraction experiments provided evidence that the kind of substrates cause a deviation of c-axis lattice constant due to the constitution of a oxide mixture (ZnO and MgO) in combination with different intermetallic compounds(Mg{sub 2}Zn{sub 11} and Mg{sub 4}Zn{sub 7}) in the growth films. The substitutional and interstitial sites of Mg{sup 2+} instead of Zn{sup 2+} ions in the lattice are the most probable mechanism to form intermetallic compounds. The optical parameters as well as thickness of the films were calculated by Spectroscopic Ellipsometry using the classical dispersion model based on the sum of the single and double Lorentz and Drude oscillators in combination with Kato-Adachi equations, as well as X-ray reflectivity.

Self-Catalyzed Growth and Characterization of In(As)P Nanowires on InP(111)B Using Metal-Organic Chemical Vapor Deposition.

Science.gov (United States)

Park, Jeung Hun; Pozuelo, Marta; Setiawan, Bunga P D; Chung, Choong-Heui

2016-12-01

We report the growth of vertical -oriented InAs x P1-x (0.11 ≤ x ≤ 0.27) nanowires via metal-organic chemical vapor deposition in the presence of indium droplets as catalysts on InP(111)B substrates at 375 °C. Trimethylindium, tertiarybutylphosphine, and tertiarybutylarsine are used as the precursors, corresponding to P/In and As/In molar ratios of 29 and 0.01, respectively. The as-grown nanowire growth morphologies, crystallinity, composition, and optical characteristics are determined using a combination of scanning and transmission electron microscopies, electron diffraction, and X-ray photoelectron, energy dispersive X-ray, and Raman spectroscopies. We find that the InAs x P1-x nanowires are tapered with narrow tops, wider bases, and In-rich In-As alloy tips, characteristic of vapor-liquid-solid process. The wires exhibit a mixture of zinc blende and wurtzite crystal structures and a high density of structural defects such as stacking faults and twins. Our results suggest that the incorporation of As into InP wires decreases with increasing substrate temperature. The Raman spectra obtained from the In(As)P nanowires reveal a red-shift and lower intensity of longitudinal optical mode relative to both InP nanowires and InP(111)B bulk, due to the incorporation of As into the InP matrix.

MEMS Lubrication by In-Situ Tribochemical Reactions From the Vapor Phase.

Energy Technology Data Exchange (ETDEWEB)

Dugger, Michael Thomas; Asay, David B.; Kim, Seong H.

2008-01-01

Vapor Phase Lubrication (VPL) of silicon surfaces with pentanol has been demonstrated. Two potential show stoppers with respect to application of this approach to real MEMS devices have been investigated. Water vapor was found to reduce the effectiveness of VPL with alcohol for a given alcohol concentration, but the basic reaction mechanism observed in water-free environments is still active, and devices operated much longer in mixed alcohol and water vapor environments than with chemisorbed monolayer lubricants alone. Complex MEMS gear trains were successfully lubricated with alcohol vapors, resulting in a factor of 104 improvement in operating life without failure. Complex devices could be made to fail if operated at much higher frequencies than previously used, and there is some evidence that the observed failure is due to accumulation of reaction products at deeply buried interfaces. However, if hypothetical reaction mechanisms involving heated surfaces are valid, then the failures observed at high frequency may not be relevant to operation at normal frequencies. Therefore, this work demonstrates that VPL is a viable approach for complex MEMS devices in conventional packages. Further study of the VPL reaction mechanisms are recommended so that the vapor composition may be optimized for low friction and for different substrate materials with potential application to conventionally fabricated, metal alloy parts in weapons systems. Reaction kinetics should be studied to define effective lubrication regimes as a function of the partial pressure of the vapor phase constituent, interfacial shear rate, substrate composition, and temperature.

Method development for the determination of cadmium, copper, lead, selenium and thallium in sediments by slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry and isotopic dilution calibration

International Nuclear Information System (INIS)

Dias, Lucia Felicidade; Miranda, Gilson R.; Saint'Pierre, Tatiana D.; Maia, Sandra M.; Frescura, Vera L.A.; Curtius, Adilson J.

2005-01-01

A procedure for the determination of Cd, Cu, Pb, Se and Tl by slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) with calibration by isotopic dilution is proposed. The slurry is prepared by mixing the sample with diluted nitric and hydrofluoric acids in an ultrasonic bath and then in a water bath at 60 deg C for 120 min. The slurries were let to stand at least for 12 h, manually shaken before poured into the autosampler cups and homogenized by passing through an argon flow, just before pipetting it into the furnace. The analytes were determined in two groups, according to their thermal behaviors. The furnace temperature program was optimized and the selected compromised pyrolysis temperatures were: 400 deg C for Cd, Se and Tl and 700 deg C for Cu and Pb. The vaporization temperature was 2300 deg C. The analyses were carried out without modifier as no significant effect was observed for different tested modifiers. Different sample particle sizes did not affect the sensitivity significantly, then a particle size ≤50 μm was adopted. The accuracy was checked by analyzing five certified reference sediments, with analytes concentrations from sub-μg g -1 to a few hundreds μg g -1 . The great majority of the obtained concentrations were in agreement with the certified values. The detection limits, determined for the MESS-2 certified sediment, were, in μg g -1 : 0.01 for Cd; 0.8 for Cu; 0.4 for Pb; 0.4 for Se and 0.06 for Tl. The precision was adequate with relative standard deviations lower than 12%. Isotopic dilution showed to be an efficient calibration technique for slurry, as the extraction of the analyte to the liquid phase of the slurry and the reactions in the vaporizer must help the equilibration between the added isotope and the isotope in the sample

Petroleum Vapor Intrusion

Science.gov (United States)

One type of vapor intrusion is PVI, in which vapors from petroleum hydrocarbons such as gasoline, diesel, or jet fuel enter a building. Intrusion of contaminant vapors into indoor spaces is of concern.

Promising technology for the melting and decontamination of dismantled metal by an induction cold crucible

International Nuclear Information System (INIS)

Suzuki, M.; Tsurumaki, K.; Akiyama, T.; Fukumura, N.; Tanaka, T.; Yoshida, M.; Ikenaga, Y.

1998-01-01

An induction cold crucible melting is one of the most promising technology for the reuse and decontamination of the radioactively contaminated metallic materials generated during the dismantling of nuclear facilities, because the crucible ensures a long life operation without generating the secondary wastes. Based on the knowledge obtained through the fundamental study using the crucible of 45 mm in diameter, the MERC(Melting and Recycling of Metals by -Cold Crucible) process was designed, manufactured and scaled up to 100-140 mm in diameter. Not only cylindrical sectional crucibles but also rectangular slab sectional crucibles were developed. The maximum power of the high frequency generator is 150 kW and the frequency is 25 kHz. In the MERC, either fragments of stainless steel or tubing and pipings with small section, which were the surrogates of contaminated metallic materials, were continuously supplied together with the flux for the decontamination, followed by melting in the crucible and pulling down by the precise withdrawal system ensuring the melt dome to be kept at a suitable level for the melting. The maximal withdrawal velocity employed was 12 mm/min. The Ingot and slab were cut in every 300 mm length by the mechanical saw. They were automatically transported to the outlet of the equipment by the conveying system. Heat efficiency of the MERC was more than 26%. The ingot surface was smooth and crack free, facilitating the removal of radioactive elements concentrated in a slag stuck on the ingot surface. There was no macro segregation inside. Tracer elements of Sr and Hf transferred to the slag, Cs and Zn to the dust. Co and Mn mostly remained in the ingot. However, up to 10% of Co could transfer to the slag. This work was done under the sponsorship of Science and Technology Agency of Japan. (author)

Metal/Carbon Hybrid Nanostructures Produced from Plasma-Enhanced Chemical Vapor Deposition over Nafion-Supported Electrochemically Deposited Cobalt Nanoparticles

Directory of Open Access Journals (Sweden)

Mohammad Islam

2018-04-01

Full Text Available In this work, we report development of hybrid nanostructures of metal nanoparticles (NP and carbon nanostructures with strong potential for catalysis, sensing, and energy applications. First, the etched silicon wafer substrates were passivated for subsequent electrochemical (EC processing through grafting of nitro phenyl groups using para-nitrobenzene diazonium (PNBT. The X-ray photoelectron spectroscope (XPS and atomic force microscope (AFM studies confirmed presence of few layers. Cobalt-based nanoparticles were produced over dip or spin coated Nafion films under different EC reduction conditions, namely CoSO4 salt concentration (0.1 M, 1 mM, reduction time (5, 20 s, and indirect or direct EC reduction route. Extensive AFM examination revealed NP formation with different attributes (size, distribution depending on electrochemistry conditions. While relatively large NP with >100 nm size and bimodal distribution were obtained after 20 s EC reduction in H3BO3 following Co2+ ion uptake, ultrafine NP (<10 nm could be produced from EC reduction in CoSO4 and H3BO3 mixed solution with some tendency to form oxides. Different carbon nanostructures including few-walled or multiwalled carbon nanotubes (CNT and carbon nanosheets were grown in a C2H2/NH3 plasma using the plasma-enhanced chemical vapor deposition technique. The devised processing routes enable size controlled synthesis of cobalt nanoparticles and metal/carbon hybrid nanostructures with unique microstructural features.

Fabrication of 100 A class, 1 m long coated conductor tapes by metal organic chemical vapor deposition and pulsed laser deposition

Energy Technology Data Exchange (ETDEWEB)

Selvamanickam, V.; Lee, H.G.; Li, Y.; Xiong, X.; Qiao, Y.; Reeves, J.; Xie, Y.; Knoll, A.; Lenseth, K

2003-10-15

SuperPower has been scaling up YBa{sub 2}Cu{sub 3}O{sub x}-based second-generation superconducting tapes by techniques such as pulsed laser deposition (PLD) using industrial laser and metal organic chemical vapor deposition (MOCVD). Both techniques offer advantage of high deposition rates, which is important for high throughput. Using highly-polished substrates produced in a reel-to-reel polishing facility and buffer layers deposited in a pilot ion beam assisted deposition facility, meter-long second-generation high temperature superconductor tapes have been produced. 100 A class, meter-long coated conductor tapes have been reproducibly demonstrated in this work by both MOCVD and PLD. The best results to date are 148 A over 1.06 m by MOCVD and 135 A over 1.1 m by PLD using industrial laser.

Surfactant effects of indium on cracking in AlN/GaN distributed Bragg reflectors grown via metal organic vapor phase epitaxy

Science.gov (United States)

Rodak, L. E.; Miller, C. M.; Korakakis, D.

2011-01-01

Aluminum Nitride (AlN) and Gallium Nitride (GaN) superlattice structures are often characterized by a network of cracks resulting from the large lattice mismatch and difference in thermal expansion coefficients, especially as the thickness of the layers increases. This work investigates the influence of indium as a surfactant on strain and cracking in AlN/GaN DBRs grown via Metal Organic Vapor Phase Epitaxy (MOVPE). DBRs with peak reflectivities ranging from 465 nm to 540 nm were grown and indium was introduced during the growth of the AlN layer. Image processing techniques were used to quantify the crack length per square millimeter and it was observed that indium has a significant effect on the crack formation and reduced the total crack length in these structures by a factor of two.

Substrate Effect on Plasma Clean Efficiency in Plasma Enhanced Chemical Vapor Deposition System

Directory of Open Access Journals (Sweden)

Shiu-Ko JangJian

2007-01-01

Full Text Available The plasma clean in a plasma-enhanced chemical vapor deposition (PECVD system plays an important role to ensure the same chamber condition after numerous film depositions. The periodic and applicable plasma clean in deposition chamber also increases wafer yield due to less defect produced during the deposition process. In this study, the plasma clean rate (PCR of silicon oxide is investigated after the silicon nitride deposited on Cu and silicon oxide substrates by remote plasma system (RPS, respectively. The experimental results show that the PCR drastically decreases with Cu substrate compared to that with silicon oxide substrate after numerous silicon nitride depositions. To understand the substrate effect on PCR, the surface element analysis and bonding configuration are executed by X-ray photoelectron spectroscopy (XPS. The high resolution inductively coupled plasma mass spectrometer (HR-ICP-MS is used to analyze microelement of metal ions on the surface of shower head in the PECVD chamber. According to Cu substrate, the results show that micro Cu ion and the CuOx bonding can be detected on the surface of shower head. The Cu ion contamination might grab the fluorine radicals produced by NF3 ddissociation in the RPS and that induces the drastic decrease on PCR.

A high selective cataluminescence sensor for the determination of tetrahydrofuran vapor

Science.gov (United States)

Cao, Xiaoan; Dai, Huimei; Chen, Suilin; Zeng, Jiayi; Zhang, Keke; Sun, Yan

2013-02-01

A novel tetrahydrofuran (THF) vapor sensor was designed based on the cataluminescence (CTL) of THF on nanosized γ-Al2O3/MgO (mol ratio = 1.5:1). SEM and XRD were applied for its characterization. We found that the CTL was strongly produced when THF vapor flowed through a nanosized Al-Mg mixed-metal oxide surface, while the CTL was weakly generated when THF vapor flowed through a single nanosized γ-Al2O3 or MgO surface. Quantitative analysis was performed at an optimal temperature of 279 °C, a wavelength of 460 nm and a flow rate of 360 mL min-1. The linear range of the CTL intensity versus concentrations of THF vapor was 1.0-3000 mL m-3 with a detection limit of 0.67 mL m-3. No (or only very low) interference was observed by formaldehyde, methanol, ethanol, benzene, toluene, ethyl acetate, ammonia, cyclohexane, chloroform, glycol armour ether, glycol ether, isopropyl ether and n-butyl ether or acetic acid. Since the response of the sensor was rapid and the system was easy to handle, we believe that the sensor has great potential for real-world use.

Characterization of N-polar AlN in GaN/AlN/(Al,Ga)N heterostructures grown by metal-organic chemical vapor deposition

Science.gov (United States)

Li, Haoran; Mazumder, Baishakhi; Bonef, Bastien; Keller, Stacia; Wienecke, Steven; Speck, James S.; Denbaars, Steven P.; Mishra, Umesh K.

2017-11-01

In GaN/(Al,Ga)N high-electron-mobility transistors (HEMT), AlN interlayer between GaN channel and AlGaN barrier suppresses alloy scattering and significantly improves the electron mobility of the two-dimensional electron gas. While high concentrations of gallium were previously observed in Al-polar AlN interlayers grown by metal-organic chemical vapor deposition, the N-polar AlN (Al x Ga1-x N) films examined by atom probe tomography in this study exhibited aluminum compositions (x) equal to or higher than 95% over a wide range of growth conditions. The also investigated AlN interlayer in a N-polar GaN/AlN/AlGaN/ S.I. GaN HEMT structure possessed a similarly high x content.

Low temperature synthesis of Zn nanowires by physical vapor deposition

Energy Technology Data Exchange (ETDEWEB)

Schroeder, Philipp; Kast, Michael; Brueckl, Hubert [Austrian Research Centers GmbH ARC, Nano- Systemtechnologies, Donau-City-Strasse 1, A-1220 Wien (Austria)

2007-07-01

We demonstrate catalytic growth of zinc nanowires by physical vapor deposition at modest temperatures of 125-175 C on various substrates. In contrast to conventional approaches using tube furnaces our home-built growth system allows to control the vapor sources and the substrate temperature separately. The silicon substrates were sputter coated with a thin gold layer as metal catalyst. The samples were heated to the growth temperature and subsequently exposed to the zinc vapor at high vacuum conditions. The work pressure was adjusted by the partial pressure of oxygen or argon flow gas. Scanning electron microscopy and atomic force microscopy characterizations revealed that the nanowires exhibit straight, uniform morphology and have diameters in the range of 50-350 nm and lengths up to 70 {mu}m. The Zn nanowires grow independently of the substrates crystal orientation via a catalytic vapor-solid growth mechanism. Since no nanowire formation was observed without gold coating, we expect that the onedimensional growth is initiated by a surface reactive Au seed. ZnO nanowires can be produced in the same preparation chamber by oxidation at 500 C in 1atm (80% Ar, 20% O{sub 2}) for 1 hour. ZnO is highly attractive for sensor applications.

Aerosol - assisted Chemical Vapor Deposition of Metal Oxide Structures: Zinc Oxide Rods

Czech Academy of Sciences Publication Activity Database

Vallejos, S.; Pizúrová, Naděžda; Čechal, J.; Grácia, I.; Cané, C.

2017-01-01

Roč. 2017, Č. 127 (2017), č. článku e56127. ISSN 1940-087X Institutional support: RVO:68081723 Keywords : Zinc oxide * columnar structures * rods * AACVD * non-catalyzed growth * vapor-solid mechanism Subject RIV: CA - Inorganic Chemistry OBOR OECD: Polymer science Impact factor: 1.232, year: 2016 https://www.jove.com/video/56127

Dispersion-Engineered Traveling Wave Kinetic Inductance Parametric Amplifier

Science.gov (United States)

Zmuidzinas, Jonas (Inventor); Day, Peter K. (Inventor)

2014-01-01

A traveling wave kinetic inductance parametric amplifier comprises a superconducting transmission line and a dispersion control element. The transmission line can include periodic variations of its dimension along its length. The superconducting material can include a high normal state resistivity material. In some instances the high normal state resistivity material includes nitrogen and a metal selected from the group consisting of titanium, niobium and vanadium. The traveling wave kinetic inductance parametric amplifier is expected to exhibit a noise temperature below 100 mK/GHz.

Hydrolytically stable fluorinated metal-organic frameworks for energy-efficient dehydration

KAUST Repository

Cadiau, Amandine; Belmabkhout, Youssef; Adil, Karim; Bhatt, Prashant; Pillai, Renjith S.; Shkurenko, Aleksander; Martineau-Corcos, Charlotte; Maurin, Guillaume; Eddaoudi, Mohamed

2017-01-01

fluorinated metal-organic framework, AlFFIVE-1-Ni (KAUST-8), with a periodic array of open metal coordination sites and fluorine moieties within the contracted square-shaped one-dimensional channel. This material selectively removed water vapor from gas

Numerical analysis of fragmentation mechanisms in vapor explosions

Energy Technology Data Exchange (ETDEWEB)

Koshizuka, Seiichi; Ikeda, Hirokazu; Oka, Yoshiaki [Tokyo Univ., Tokai, Ibaraki (Japan). Nuclear Engineering Research Lab.

1998-01-01

Fragmentation of molten metal is the key process in vapor explosions. However this process is so rapid that the mechanisms have not been clarified yet in the experimental studies. Besides, numerical simulation is difficult because we have to analyze water, steam and molten metal simultaneously with evaporation and fragmentation. The authors have been developing a new numerical method, the Moving Particle Semi-implicit (MPS) method, based on moving particles and their interactions. Grids are not necessary. Incompressible flows with fragmentation on free surfaces have been calculated successfully using the MPS method. In the present study numerical simulation of the fragmentation processes using the MPS method is carried out to investigate the mechanisms. A numerical model to calculate evaporation from water to steam is developed. In this model, new particles are generated on water-steam interfaces. Effect of evaporation is also investigated. Growth of the filament is not accelerated when the normal evaporation is considered. This is because the normal evaporation needs a longer time than the moment of the jet impingement, though the filament growth is decided in this moment. Next, rapid evaporation based on spontaneous nucleation is considered. The filament growth is markedly accelerated. This result is consistent with the experimental fact that the spontaneous nucleation temperature is a necessary condition of small-scale vapor explosions. (J.P.N.)

Evidence for the direct ejection of clusters from non-metallic solids during laser vaporization

International Nuclear Information System (INIS)

Bloomfield, L.A.; Yang, Y.A.; Xia, P.; Junkin, A.L.

1991-01-01

This paper reports on the formation of molecular scale particles or clusters of alkali halides and semiconductors during laser vaporization of solids. By measuring the abundances of cluster ions produced in several different source configurations, the authors have determined that clusters are ejected directly from the source sample and do not need to grow from atomic or molecular vapor. Using samples of mixed alkali halide powders, the authors have found that unalloyed clusters are easily produced in a source that prevents growth from occurring after the clusters leave the sample surface. However, melting the sample or encouraging growth after vaporization lead to the production of alloyed cluster species. The sizes of the ejected clusters are initially random, but the population spectrum quickly becomes structured as hot, unstable-sized clusters decay into smaller particles. In carbon, large clusters with odd number of atoms decay almost immediately. The hot even clusters also decay, but much more slowly. The longest lived clusters are the magic C 50 and C 60 fullerenes. The mass spectrum of large carbon clusters evolves in time from structureless, to only the even clusters, to primarily C 50 and C 60 . If cluster growth is encouraged, the odd clusters reappear and the population spectrum again becomes relatively structureless

Annular linear induction pump with an externally supported duct

International Nuclear Information System (INIS)

1980-01-01

An annular linear induction pump of increased efficiency is described, capable of being readily disassembled for repair or replacement of parts, and having one pass flow of the liquid metal through the pump. (U.K.)

Organometallic vapor-phase epitaxy theory and practice

CERN Document Server

Stringfellow, Gerald B

1989-01-01

Here is one of the first single-author treatments of organometallic vapor-phase epitaxy (OMVPE)--a leading technique for the fabrication of semiconductor materials and devices. Also included are metal-organic molecular-beam epitaxy (MOMBE) and chemical-beam epitaxy (CBE) ultra-high-vacuum deposition techniques using organometallic source molecules. Of interest to researchers, students, and people in the semiconductor industry, this book provides a basic foundation for understanding the technique and the application of OMVPE for the growth of both III-V and II-VI semiconductor materials and the

Rapid and highly efficient growth of graphene on copper by chemical vapor deposition of ethanol

Energy Technology Data Exchange (ETDEWEB)

Lisi, Nicola, E-mail: nicola.lisi@enea.it [ENEA, Materials Technology Unit, Surface Technology Laboratory, Casaccia Research Centre, Via Anguillarese 301, 00123 Rome (Italy); Buonocore, Francesco; Dikonimos, Theodoros; Leoni, Enrico [ENEA, Materials Technology Unit, Surface Technology Laboratory, Casaccia Research Centre, Via Anguillarese 301, 00123 Rome (Italy); Faggio, Giuliana; Messina, Giacomo [Dipartimento di Ingegneria dell' Informazione, delle Infrastrutture e dell' Energia Sostenibile (DIIES), Università “Mediterranea” di Reggio Calabria, 89122 Reggio Calabria (Italy); Morandi, Vittorio; Ortolani, Luca [CNR-IMM Bologna, Via Gobetti 101, 40129 Bologna (Italy); Capasso, Andrea [ENEA, Materials Technology Unit, Surface Technology Laboratory, Casaccia Research Centre, Via Anguillarese 301, 00123 Rome (Italy)

2014-11-28

The growth of graphene by chemical vapor deposition on metal foils is a promising technique to deliver large-area films with high electron mobility. Nowadays, the chemical vapor deposition of hydrocarbons on copper is the most investigated synthesis method, although many other carbon precursors and metal substrates are used too. Among these, ethanol is a safe and inexpensive precursor that seems to offer favorable synthesis kinetics. We explored the growth of graphene on copper from ethanol, focusing on processes of short duration (up to one min). We investigated the produced films by electron microscopy, Raman and X-ray photoemission spectroscopy. A graphene film with high crystalline quality was found to cover the entire copper catalyst substrate in just 20 s, making ethanol appear as a more efficient carbon feedstock than methane and other commonly used precursors. - Highlights: • Graphene films were grown by fast chemical vapor deposition of ethanol on copper. • High-temperature/short-time growth produced highly crystalline graphene. • The copper substrate was entirely covered by a graphene film in just 20 s. • Addition of H{sub 2} had a negligible effect on the crystalline quality.

Concentrations of metals in blood and feathers of nestling ospreys (Pandion haliaetus) in Chesapeake and Delaware Bays

Science.gov (United States)

Rattner, B.A.; Golden, N.H.; Toschik, P.C.; McGowan, P.C.; Custer, T.W.

2008-01-01

In 2000, 2001, and 2002, blood and feather samples were collected from 40-45-day-old nestling ospreys (Pandion haliaetus) from Chesapeake Bay and Delaware Bay and River. Concentrations of 18 metals, metalloids, and other elements were determined in these samples by inductively coupled plasma-mass spectroscopy, and Hg concentrations were measured by cold vapor atomic absorption spectroscopy. When compared to concurrent reference areas (South, West, and Rhode Rivers), mean As and Hg concentrations in blood were greater (p nestlings from the highly industrialized Elizabeth River compared to the rural reference area. When compared to the concurrent reference area, mean Al, Ba, Hg, Mn, and Pb concentrations in feathers were substantially greater (p nestlings from northern Delaware Bay and River had greater concentrations (p nestling feathers from Delaware were frequently greater than in the Chesapeake. The present findings and those of related reproductive studies suggest that concentrations of several heavy metals (e.g., Cd, Hg, Pb) in nestling blood and feathers from Chesapeake and Delaware Bays were below toxicity thresholds and do not seem to be affecting chick survival during the nestling period.

Controllable chemical vapor deposition of large area uniform nanocrystalline graphene directly on silicon dioxide

DEFF Research Database (Denmark)

Sun, Jie; Lindvall, Niclas; Cole, Matthew T.

2012-01-01

Metal-catalyst-free chemical vapor deposition (CVD) of large area uniform nanocrystalline graphene on oxidized silicon substrates is demonstrated. The material grows slowly, allowing for thickness control down to monolayer graphene. The as-grown thin films are continuous with no observable pinholes...

Ultratrace determination of Pb, Se and As in wine samples by electrothermal vaporization inductively coupled plasma mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Grindlay, Guillermo, E-mail: guillermo.grindlay@ua.es [Department of Analytical Chemistry, Nutrition and Food Sciences, University of Alicante, PO Box 99, 03080 - Alicante (Spain); Mora, Juan; Gras, Luis [Department of Analytical Chemistry, Nutrition and Food Sciences, University of Alicante, PO Box 99, 03080 - Alicante (Spain); de Loos-Vollebregt, M.T.C. [Delft University of Technology, Fac. Applied Sciences, Julianalaan 67, 2628 BC - Delft (Netherlands)

2009-10-12

The determination of Pb, Se and As in wine has a great interest due to health risks and legal requirements. To perform the analysis of wine, two considerations must be taken into account: (i) the low concentration level of the analytes; and (ii) the risk of interferences due to wine matrix components. The goal of this work is to evaluate electrothermal vaporization (ETV) sample introduction for ultratrace determination of Pb, Se and As in wine samples by inductively coupled plasma mass spectrometry (ICP-MS). The results obtained with ETV-ICP-MS were compared to those obtained with conventional liquid sample introduction in ICP-MS and electrothermal atomic absorption spectrometry (ETAAS). Analytical figures of merit of ETV sample introduction strongly depend on the amount of wine sample, on the modifier nature (i.e. Pd, ascorbic acid or citric acid) and concentration and on the temperature program. Wine matrix components exert a great influence on analyte transport efficiency. Due to this fact, the analysis of wine cannot be performed by means of external calibration but the standard addition methodology should be used. The determination of Pb and Se in wine by ETV-ICP-MS provides similar results as conventional liquid sample introduction ICP-MS. For As, the concentration values obtained with ETV sample introduction were between two and four times lower than with the conventional system. These differences are related to the lower intensity of polyatomic interferences (i.e. {sup 40}Ar{sup 35}Cl{sup +} vs. {sup 75}As{sup +}) obtained for ETV sample introduction when compared to the conventional system. Finally, no differences for Pb determination were observed between ETV sample introduction and ETAAS. Unfortunately, the limits of detection for As and Se in ETAAS were not low enough to quantify these elements in the wine samples tested.

Ultratrace determination of Pb, Se and As in wine samples by electrothermal vaporization inductively coupled plasma mass spectrometry

International Nuclear Information System (INIS)

Grindlay, Guillermo; Mora, Juan; Gras, Luis; de Loos-Vollebregt, M.T.C.

2009-01-01

The determination of Pb, Se and As in wine has a great interest due to health risks and legal requirements. To perform the analysis of wine, two considerations must be taken into account: (i) the low concentration level of the analytes; and (ii) the risk of interferences due to wine matrix components. The goal of this work is to evaluate electrothermal vaporization (ETV) sample introduction for ultratrace determination of Pb, Se and As in wine samples by inductively coupled plasma mass spectrometry (ICP-MS). The results obtained with ETV-ICP-MS were compared to those obtained with conventional liquid sample introduction in ICP-MS and electrothermal atomic absorption spectrometry (ETAAS). Analytical figures of merit of ETV sample introduction strongly depend on the amount of wine sample, on the modifier nature (i.e. Pd, ascorbic acid or citric acid) and concentration and on the temperature program. Wine matrix components exert a great influence on analyte transport efficiency. Due to this fact, the analysis of wine cannot be performed by means of external calibration but the standard addition methodology should be used. The determination of Pb and Se in wine by ETV-ICP-MS provides similar results as conventional liquid sample introduction ICP-MS. For As, the concentration values obtained with ETV sample introduction were between two and four times lower than with the conventional system. These differences are related to the lower intensity of polyatomic interferences (i.e. 40 Ar 35 Cl + vs. 75 As + ) obtained for ETV sample introduction when compared to the conventional system. Finally, no differences for Pb determination were observed between ETV sample introduction and ETAAS. Unfortunately, the limits of detection for As and Se in ETAAS were not low enough to quantify these elements in the wine samples tested.

Numerical Simulation of the Moving Induction Heating Process with Magnetic Flux Concentrator

Directory of Open Access Journals (Sweden)

Feng Li

2013-01-01

Full Text Available The induction heating with ferromagnetic metal powder bonded magnetic flux concentrator (MPB-MFC demonstrates more advantages in surface heating treatments of metal. However, the moving heating application is mostly applied in the industrial production. Therefore, the analytical understanding of the mechanism, efficiency, and controllability of the moving induction heating process becomes necessary for process design and optimization. This paper studies the mechanism of the moving induction heating with magnetic flux concentrator. The MPB-MFC assisted moving induction heating for Inconel 718 alloy is studied by establishing the finite element simulation model. The temperature field distribution is analyzed, and the factors influencing the temperature are studied. The conclusion demonstrates that the velocity of the workpiece should be controlled properly and the heat transfer coefficient (HTC has little impact on the temperature development, compared with other input parameters. In addition, the validity of the static numerical model is verified by comparing the finite element simulation with experimental results on AISI 1045 steel. The numerical model established in this work can provide comprehensive understanding for the process control in production.

Fabrication of single-phase ε-GaSe films on Si(100) substrate by metal organic chemical vapor deposition

Energy Technology Data Exchange (ETDEWEB)

Chang, Chia-Chen; Zeng, Jia-Xian; Lan, Shan-Ming [Department of Electronic Engineering, College of Electrical Engineering and Computer Science, Chung Yuan Christian University, Chung-Li 32023, Taiwan (China); Uen, Wu-Yih, E-mail: uenwuyih@ms37.hinet.net [Department of Electronic Engineering, College of Electrical Engineering and Computer Science, Chung Yuan Christian University, Chung-Li 32023, Taiwan (China); Liao, Sen-Mao [Department of Electronic Engineering, College of Electrical Engineering and Computer Science, Chung Yuan Christian University, Chung-Li 32023, Taiwan (China); Yang, Tsun-Neng; Ma, Wei-Yang [Institute of Nuclear Energy Research, P.O. Box 3-11, Lungtan 32500, Taiwan (China); Chang, Kuo-Jen [Chung-Shan Institute of Science and Technology, No.15, Shi Qi Zi, Gaoping Village, Longtan Township, Taoyuan County, Taiwan (China)

2013-09-02

Single-phase ε-gallium selenide (GaSe) films were fabricated on Si(100) substrate by metal organic chemical vapor deposition using dual-source precursors: triethylgallium (TEG) and hydrogen selenide (H{sub 2}Se) with the flow ratio of [H{sub 2}Se]/[TEG] being maintained at 1.2. In particular, an arsine (AsH{sub 3}) flow was introduced to the Si substrate before the film deposition to induce an arsenic (As)-passivation effect on the substrate. The crystalline structure of GaSe films prepared was analyzed using X-ray diffraction and the surface morphology of them was characterized by scanning electron microscopy. It was found that the film quality could be improved by the As-passivation effect. The optical properties of the films were studied by temperature dependent photoluminescence (PL) measurements. PL spectra obtained with different distributions and intensities favored for resolving the superior material quality of the films produced on the substrate with As-passivation compared to those produced on the substrate without As-passivation. The former was dominated by the excitonic emissions for the whole temperature range of 20–300 K examined, while the latter was initially dominated by the defect-related emission at 1.907 eV for a low-temperature range ≦ 80 K and then became dominated by the weak excitonic emission band instead. The ε modification of GaSe films prepared was further recognized by the Raman scattering measurements conducted at room temperature. - Highlights: • Gallium selenide (GaSe) layered structures are fabricated on Si(100) substrate. • Metal–organic chemical vapor deposition is used for film fabrication. • Arsenic-passivation effects of Si substrate on the GaSe film quality are analyzed. • Photoluminescence measurements of GaSe polycrystals are reported.

水和丙酮工质的金属纤维毡蒸气腔热管的传热性能%Thermal performance of vapor chamber heat pipe with metal felt wick of water or acetone working fluid

Institute of Scientific and Technical Information of China (English)

徐鹏程; 陶汉中; 张红

2015-01-01

通过实验研究了金属纤维毡吸液芯蒸气腔热管的传热特性，测试了在单一热源下，不同热通量、风速以及工质种类时蒸气腔热管的启动性能与均温特性，并使用红外热像仪对蒸气腔热管冷凝端拍摄。实验中蒸气腔热管使用的工质分别为水与丙酮。实验结果表明：金属纤维毡蒸气腔热管的启动时间基本在3000 s左右；蒸气腔热管的蒸发端与冷凝端的等温性能良好，其中水工质的冷热端最小温差为1.35℃，因此使用金属纤维毡吸液芯蒸气腔热管可以避免电子器件的局部高温。%The heat transfer characteristics of the vapor chamber heat pipe with metal fiber felt wick were studied by experiments. Under different conditions, the isothermal characteristics and startup performance of the vapor chamber heat pipe using a single heat source were tested. The variables were heat flux, cooling wind speed and working fluid. The condenser section of the vapor chamber heat pipe was filmed by infrared thermography. The working fluid used in the vapor chamber heat pipe was water or acetone. The vapor chamber heat pipe could startup smoothly from ambient temperature at different heating powers, and startup time was about 3000 s. Both evaporator and condenser sections of the vapor chamber heat pipe had good isothermal performance, and the minimum temperature difference of the heat pipe using water as working fluid was 1.35℃. So electronic devices could avoid local high temperature by using the vapor chamber heat pipe with metal fiber felt wick.

Evaluation of pyrolysis curves for volatile elements in aqueous standards and carbon-containing matrices in electrothermal vaporization inductively coupled plasma mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Silva, A.F. [Delft University of Technology, Faculty of Applied Sciences, DelftChemTech, Julianalaan 136, 2628 BL Delft (Netherlands); Universidade Federal de Santa Catarina, Departamento de Quimica, 88040-900 Florianopolis, SC (Brazil); Welz, B. [Universidade Federal de Santa Catarina, Departamento de Quimica, 88040-900 Florianopolis, SC (Brazil); Loos-Vollebregt, M.T.C. de [Delft University of Technology, Faculty of Applied Sciences, DelftChemTech, Julianalaan 136, 2628 BL Delft (Netherlands)], E-mail: m.t.c.deloos-vollebregt@tudelft.nl

2008-07-15

Pyrolysis curves in electrothermal atomic absorption spectrometry (ET AAS) and electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) have been compared for As, Se and Pb in lobster hepatopancreas certified reference material using Pd/Mg as the modifier. The ET AAS pyrolysis curves confirm that the analytes are not lost from the graphite furnace up to a pyrolysis temperature of 800 deg. C. Nevertheless, a downward slope of the pyrolysis curve was observed for these elements in the biological material using ETV-ICP-MS. This could be related to a gain of sensitivity at low pyrolysis temperatures due to the matrix, which can act as carrier and/or promote changes in the plasma ionization equilibrium. Experiments with the addition of ascorbic acid to the aqueous standards confirmed that the higher intensities obtained in ETV-ICP-MS are related to the presence of organic compounds in the slurry. Pyrolysis curves for As, Se and Pb in coal and coal fly ash were also investigated using the same Pd/Mg modifier. Carbon intensities were measured in all samples using different pyrolysis temperatures. It was observed that pyrolysis curves for the three analytes in all slurry samples were similar to the corresponding graphs that show the carbon intensity for the same slurries for pyrolysis temperatures from 200 deg. C up to 1000 deg. C.

Application of direct solid sample analysis for the determination of chlorine in biological materials using electrothermal vaporization inductively coupled plasma mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Santos de Gois, Jefferson; Pereira, Éderson R. [Departamento de Química, Universidade Federal de Santa Catarina, 88040-970 Florianópolis, SC (Brazil); Welz, Bernhard [Departamento de Química, Universidade Federal de Santa Catarina, 88040-970 Florianópolis, SC (Brazil); INCT de Energia e Ambiente do CNPq (Brazil); Borges, Daniel L.G., E-mail: daniel.borges@ufsc.br [Departamento de Química, Universidade Federal de Santa Catarina, 88040-970 Florianópolis, SC (Brazil); INCT de Energia e Ambiente do CNPq (Brazil)

2015-03-01

This work describes a methodology developed to carry out Cl determination in biological materials using electrothermal vaporization inductively coupled plasma mass spectrometry and direct solid sample analysis. The solid samples were directly weighed into graphite ‘cups’ and inserted into the graphite furnace. The RF power and the carrier gas flow rate were optimized at 1300 W and 0.7 L min{sup −1}, respectively. Calibration could be carried out using aqueous standard solutions with pre-dried modifiers (Pd + Nd or Pd + Ca) or using solid certified reference materials with the same pre-dried modifiers or without the use of modifiers. The limit of quantification was determined as 5 μg g{sup −1} under optimized conditions and the Cl concentration was determined in five certified reference materials with certified concentrations for Cl, in addition to three certified reference materials, for which certified values for Cl were unavailable; in the latter case, the results were compared with those obtained using high-resolution continuum source molecular absorption spectrometry. Good agreement at a 95% statistical confidence level was achieved between determined and certified or reference values. - Highlights: • Direct determination of chlorine in solid biological materials is described for the first time using ICP-MS. • Calibration against aqueous standards is feasible. • The method is accurate and sensitive, regardless of the composition of the solid sample.

Point of net vapor generation and vapor void fraction in subcooled boiling

International Nuclear Information System (INIS)

Saha, P.; Zuber, N.

1974-01-01

An analysis is presented directed at predicting the point of net vapor generation and vapor void fraction in subcooled boiling. It is shown that the point of net vapor generation depends upon local conditions--thermal and fluid dynamic. Thus, at low mass flow rates the net vapor generation is determined by thermal conditions, whereas at high mass flow rates the phenomenon is hydrodynamically controlled. Simple criteria are derived which can be used to predict these local conditions for net vapor generation. These criteria are used to determine the vapor void fraction is subcooled boiling. Comparison between the results predicted by this analysis and experimental data presently available shows good agreement for wide range of operating conditions, fluids and geometries. (U.S.)

Parameters study on the growth of GaAs nanowires on indium tin oxide by metal-organic chemical vapor deposition

Energy Technology Data Exchange (ETDEWEB)

Wu, Dan; Tang, Xiaohong, E-mail: exhtang@ntu.edu.sg, E-mail: wangk@sustc.edu.cn; Li, Xianqiang [OPTIMUS, Photonics Centre of Excellence, School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore); Wang, Kai, E-mail: exhtang@ntu.edu.sg, E-mail: wangk@sustc.edu.cn [Department of Electrical & Electronic Engineering, South University of Science and Technology of China, 1088 Xueyuan Avenue, Shenzhen 518055 (China); Olivier, Aurelien [CINTRA UMI 3288, School of Electrical and Electronic Engineering, Nanyang Technological University, Research Techno Plaza, 50 Nanyang Drive, Border X Block, Level 6, 637553 Singapore (Singapore)

2016-03-07

After successful demonstration of GaAs nanowire (NW) epitaxial growth on indium tin oxide (ITO) by metal organic chemical vapor deposition, we systematically investigate the effect of growth parameters' effect on the GaAs NW, including temperature, precursor molar flow rates, growth time, and Au catalyst size. 40 nm induced GaAs NWs are observed with zinc-blende structure. Based on vapor-liquid-solid mechanism, a kinetic model is used to deepen our understanding of the incorporation of growth species and the role of various growth parameters in tuning the GaAs NW growth rate. Thermally activated behavior has been investigated by variation of growth temperature. Activation energies of 40 nm Au catalyst induced NWs are calculated at different trimethylgallium (TMGa) molar flow rates about 65 kJ/mol. The GaAs NWs growth rates increase with TMGa molar flow rates whereas the growth rates are almost independent of growth time. Due to Gibbs-Thomson effect, the GaAs NW growth rates increase with Au nanoparticle size at different temperatures. Critical radius is calculated as 2.14 nm at the growth condition of 430 °C and 1.36 μmol/s TMGa flow rate. It is also proved experimentally that Au nanoparticle below the critical radius such as 2 nm cannot initiate the growth of NWs on ITO. This theoretical and experimental growth parameters investigation enables great controllability over GaAs NWs grown on transparent conductive substrate where the methodology can be expanded to other III–V material NWs and is critical for potential hybrid solar cell application.

Doping characteristics of Si-doped n-GaN Epilayers grown by low-pressure metal-organic chemical-vapor deposition

CERN Document Server

Noh, S K; Park, S E; Lee, I H; Choi, I H; Son, S J; Lim, K Y; Lee, H J

1998-01-01

We studied doping behaviors through analysis of the electronic properties of a series of undoped and Si-doped GaN epilayers grown on (0001) sapphire substrates by the low-pressure metal-organic chemical-vapor deposition (LP-MOCVD) technique. The doping efficiency was in the range of 0.4 - 0.8, and an empirical relation expressed as eta = 0.45 log[Si] - 8.1 was obtained. The temperature dependence of carrier concentration showed that the donor activation energy monotonically decreased from 17.6 meV to almost zero as the doping level increased. We suggest that the reduction in the activation energy is related not to autodoped defect centers but to doped Si donors and that the behavior originates from the formation of an impurity band. On the basis of an abrupt change in the compensation ratio from 0.9 to 0.5 by Si-doping, an exceptional difference in the Hall mobility between the undoped and the Si-doped films is explained by a mixed conduction mechanism of electrons and holes.

Effect of gas flow on the selective area growth of gallium nitride via metal organic vapor phase epitaxy

Science.gov (United States)

Rodak, L. E.; Kasarla, K. R.; Korakakis, D.

2007-08-01

The effect of gas flow on the selective area growth (SAG) of gallium nitride (GaN) grown via metal organic vapor phase epitaxy (MOVPE) has been investigated. In this study, the SAG of GaN was carried out on a silicon dioxide striped pattern along the GaN direction. SAG was initiated with the striped pattern oriented parallel and normal to the incoming gas flow in a horizontal reactor. The orientation of the pattern did not impact cross section of the structure after re-growth as both orientations resulted in similar trapezoidal structures bounded by the (0 0 0 1) and {1 1 2¯ n} facets ( n≈1.7-2.2). However, the growth rates were shown to depend on the orientation of the pattern as the normally oriented samples exhibited enhanced vertical and cross-sectional growth rates compared to the parallel oriented samples. All growths occurred under identical conditions and therefore the difference in growth rates must be attributed to a difference in mass transport of species.

Research Update: A minimal region of squid reflectin for vapor-induced light scattering

Directory of Open Access Journals (Sweden)

Patrick B. Dennis

2017-12-01

Full Text Available Reflectins are a family of proteins found in the light manipulating cells of cephalopods. These proteins are made up of a series of conserved repeats that contain highly represented amino acids thought to be important for function. Previous studies demonstrated that recombinant reflectins cast into thin films produced structural colors that could be dynamically modulated via changing environmental conditions. In this study, we demonstrate light scattering from reflectin films following exposure to a series of water vapor pulses. Analysis of film surface topography shows that the induction of light scatter is accompanied by self-assembly of reflectins into micro- and nanoscale features. Using a reductionist strategy, we determine which reflectin repeats and sub-repeats are necessary for these events following water vapor pulsing. With this approach, we identify a singly represented, 23-amino acid region in reflectins as being sufficient to recapitulate the light scattering properties observed in thin films of the full-length protein. Finally, the aqueous stability of reflectin films is leveraged to show that pre-exposure to buffers of varying pH can modulate the ability of water vapor pulses to induce light scatter and protein self-assembly.

Research Update: A minimal region of squid reflectin for vapor-induced light scattering

Science.gov (United States)

Dennis, Patrick B.; Singh, Kristi M.; Vasudev, Milana C.; Naik, Rajesh R.; Crookes-Goodson, Wendy J.

2017-12-01

Reflectins are a family of proteins found in the light manipulating cells of cephalopods. These proteins are made up of a series of conserved repeats that contain highly represented amino acids thought to be important for function. Previous studies demonstrated that recombinant reflectins cast into thin films produced structural colors that could be dynamically modulated via changing environmental conditions. In this study, we demonstrate light scattering from reflectin films following exposure to a series of water vapor pulses. Analysis of film surface topography shows that the induction of light scatter is accompanied by self-assembly of reflectins into micro- and nanoscale features. Using a reductionist strategy, we determine which reflectin repeats and sub-repeats are necessary for these events following water vapor pulsing. With this approach, we identify a singly represented, 23-amino acid region in reflectins as being sufficient to recapitulate the light scattering properties observed in thin films of the full-length protein. Finally, the aqueous stability of reflectin films is leveraged to show that pre-exposure to buffers of varying pH can modulate the ability of water vapor pulses to induce light scatter and protein self-assembly.

Inductive shearing of drilling pipe

Science.gov (United States)

Ludtka, Gerard M.; Wilgen, John; Kisner, Roger; Mcintyre, Timothy

2016-04-19

Induction shearing may be used to cut a drillpipe at an undersea well. Electromagnetic rings may be built into a blow-out preventer (BOP) at the seafloor. The electromagnetic rings create a magnetic field through the drillpipe and may transfer sufficient energy to change the state of the metal drillpipe to shear the drillpipe. After shearing the drillpipe, the drillpipe may be sealed to prevent further leakage of well contents.

Electrothermal vaporization inductively coupled plasma-mass spectrometry for the determination of Cr, Cu, Cd, Hg and Pb in rice flour

International Nuclear Information System (INIS)

Li, P.-C.; Jiang, S.-J.

2003-01-01

Ultrasonic slurry sampling (USS)-electrothermal vaporization (ETV) dynamic reaction cell TM (DRC) inductively coupled plasma-mass spectrometry (ICP-MS) has been applied to determine Cr, Cu, Cd, Hg and Pb in rice samples. The influences of instrument operating conditions and slurry preparation on the ion signals were reported. Ascorbic acid was used as a modifier to enhance the ion signals. The background ions at the chromium masses were reduced in intensity significantly by using 0.4 ml min -1 NH 3 as reaction cell gas in the dynamic reaction cell while a q value of 0.6 was used. Since the sensitivities of Cr, Cu, Cd, Hg and Pb in rice flour slurry and aqueous solution were quite different, standard addition and isotope dilution methods were used for the determination of Cr, Cu, Cd, Hg and Pb in these rice samples. This method has been applied to the determination of Cr, Cu, Cd, Hg and Pb in NIST SRM 1568a rice flour reference material and two rice samples purchased from the market. The analytical results for the reference material agreed with the certified values. The results for the rice samples for which no reference values were available were also found to be in good agreement between the isotope dilution and standard addition methods. The method's detection limits estimated from the standard addition plots were about 0.44, 1.7, 0.4, 0.53 and 0.69 ng g -1 for Cr, Cu, Cd, Hg and Pb, respectively, in the original rice flour

The vapor pressure and enthalpy of vaporization of M-xylene

International Nuclear Information System (INIS)

Rothenberg, S.J.; Seiler, F.A.; Bechtold, W.E.; Eidson, A.F.

1988-01-01

We measured the vapor pressure of m-xylene over the temperature range 273 to 293 deg K with a single-sided capacitance manometer. The enthalpy of vaporization was 42.2 ± 0.1 (SE) kj/ g·mol. Combining our own data with previously published data, we recommend using the values 42.0, 40.6, and 39.1 (± 0.1) (SE) kjg·mol for the enthalpy of vaporization of m-xylene at 300, 340, and 380 deg. K, respectively, and a value for the change in heat capacity on vaporization (ΔCpdeg.) of 35 ± 3 (SE) J/g·mol·K over the temperature range studied. (author)

Metal carbonyl vapor generation coupled with dielectric barrier discharge to avoid plasma quench for optical emission spectrometry.

Science.gov (United States)

Cai, Yi; Li, Shao-Hua; Dou, Shuai; Yu, Yong-Liang; Wang, Jian-Hua

2015-01-20

The scope of dielectric barrier discharge (DBD) microplasma as a radiation source for optical emission spectrometry (OES) is extended by nickel carbonyl vapor generation. We proved that metal carbonyl completely avoids the extinguishing of plasma, and it is much more suitable for matching the DBD excitation and OES detection with respect to significant DBD quenching by concomitant hydrogen when hydride generation is used. A concentric quartz UV reactor allows sample solution to flow through the central channel wherein to efficiently receive the uniformly distributed UV irradiation in the confined cylindrical space between the concentric tubes, which facilitates effective carbonyl generation in a nickel solution. The carbonyl is transferred into the DBD excitation chamber by an argon stream for nickel excitation, and the characteristic emission of nickel at 232.0 nm is detected by a charge-coupled device (CCD) spectrometer. A 1.0 mL sample solution results in a linear range of 5-100 μg L(-1) along with a detection limit of 1.3 μg L(-1) and a precision of 2.4% RSD at 50 μg L(-1). The present DBD-OES system is validated by nickel in certified reference materials.

Energy Conversion Alternatives Study (ECAS), Westinghouse phase 1. Volume 7: Metal vapor Rankine topping-steam bottoming cycles. [energy conversion efficiency in electric power plants

Science.gov (United States)

Deegan, P. B.

1976-01-01

Adding a metal vapor Rankine topper to a steam cycle was studied as a way to increase the mean temperature at which heat is added to the cycle to raise the efficiency of an electric power plant. Potassium and cesium topping fluids were considered. Pressurized fluidized bed or pressurized (with an integrated low-Btu gasifier) boilers were assumed. Included in the cycles was a pressurizing gas turbine with its associated recuperator, and a gas economizer and feedwater heater. One of the ternary systems studied shows plant efficiency of 42.3% with a plant capitalization of $66.7/kW and a cost of electricity of 8.19 mills/MJ (29.5 mills/kWh).

Polysulfide intercalated layered double hydroxides for metal capture applications

Energy Technology Data Exchange (ETDEWEB)

Kanatzidis, Mercouri G.; Ma, Shulan

2017-04-04

Polysulfide intercalated layered double hydroxides and methods for their use in vapor and liquid-phase metal capture applications are provided. The layered double hydroxides comprise a plurality of positively charged host layers of mixed metal hydroxides separated by interlayer spaces. Polysulfide anions are intercalated in the interlayer spaces.

Liquid--liquid contact in vapor explosion

International Nuclear Information System (INIS)

Segev, A.

1978-08-01

The contact of two liquid materials, one of which is at a temperature substantially above the boiling point of the other, can lead to fast energy conversion and a subsequent shock wave. This well-known phenomenon is called a ''vapor explosion.'' One method of producing intimate, liquid--liquid contact (which is known to be a necessary condition for vapor explosion) is a shock tube configuration. Such experiments in which water was impacted upon molten aluminum showed that very high pressures, even larger than the thermodynamic critical pressure, could occur. The mechanism by which such sharp pressure pulses are generated is not yet clear. In this experiment cold liquids (Freon-11, Freon-22, water, or butanol) were impacted upon various hot materials (mineral oil, silicone oil, water, mercury, molten Wood's metal or molten salt mixture). The main conclusion from the experimental study is that hydrodynamic effects may be very significant in any shock tube analyses, especially when multiple interactions are observed. A theoretical study was performed to check the possibility of vapor film squeezing (between a drop in film boiling and a surface) as a controlling mechanism for making liquid--liquid contact. Using experimental data, the film thickness was calculated and it was found to be too thick for any conceivable film rupture mechanism. It was suggested that the coalescence is a two-stage process, in which the controlling stage depends mainly on temperature and surface properties and can be described as the ability of cold liquid to spread on a hot surface

The vapor pressure and enthalpy of vaporization of M-xylene

Energy Technology Data Exchange (ETDEWEB)

Rothenberg, S J; Seiler, F A; Bechtold, W E; Eidson, A F

1988-12-01

We measured the vapor pressure of m-xylene over the temperature range 273 to 293 deg K with a single-sided capacitance manometer. The enthalpy of vaporization was 42.2 {+-} 0.1 (SE) kj/ g{center_dot}mol. Combining our own data with previously published data, we recommend using the values 42.0, 40.6, and 39.1 ({+-} 0.1) (SE) kjg{center_dot}mol for the enthalpy of vaporization of m-xylene at 300, 340, and 380 deg. K, respectively, and a value for the change in heat capacity on vaporization ({delta}Cpdeg.) of 35 {+-} 3 (SE) J/g{center_dot}mol{center_dot}K over the temperature range studied. (author)

Metal Detector By Using PIC Microcontroller Interfacing With PC

Directory of Open Access Journals (Sweden)

Yin Min Theint

2015-06-01

Full Text Available Abstract This system proposes metal detector by using PIC microcontroller interfacing with PC. The system uses PIC microcontroller as the main controller whether the detected metal is ferrous metal or non-ferrous metal. Among various types of metal sensors and various types of metal detecting technologies concentric type induction coil sensor and VLF very low frequency metal detecting technology are used in this system. This system consists of two configurations Hardware configuration and Software configuration. The hardware components include induction coil sensors which senses the frequency changes of metal a PIC microcontroller personal computer PC buzzer light emitting diode LED and webcam. The software configuration includes a program controller interface. PIC MikroCprogramming language is used to implement the control system. This control system is based on the PIC 16F887 microcontroller.This system is mainly used in mining and high security places such as airport plaza shopping mall and governmental buildings.

Mercury accumulation and its distribution to metallothionein in mouse brain after sub-chronic pulse exposure to mercury vapor

Energy Technology Data Exchange (ETDEWEB)

Yasutake, A. [Biochemistry Section, National Institute for Minamata Disease, Minamata, Kumamoto 867-0008 (Japan); Sawada, M.; Shimada, A. [Department of Veterinary Pathology, Tottori University, 4-101 Koyamacho, Minami, Tottori 680-0945 (Japan); Satoh, M. [Department of Hygienics, Gifu Pharmaceutical University, 5-6-1 Mitahora-higashi, Gifu 502-8585 (Japan); Tohyama, C. [Environmental Health Sciences Division, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506 (Japan)

2004-09-01

Previously we found that exposure to mercury vapor effectively induced metallothionein (MT) biosynthesis in rat brain. Although the induction of not only MT-I/II but also MT-III was evident, the induction rate of the latter was much lower than that of the former. The brain of an MT-null mouse lacks MT-I/II, but has MT-III. Here we examined the effects of sub-chronic pulse exposure to mercury vapor on the brain MT in MT-null mice and their wild type controls. MT-null and wild type mice were preliminarily exposed to mercury vapor for 2 weeks at 0.1 mg Hg/m{sup 3} for 1 h/day for 3 days a week, and then exposed for 11 weeks at 4.1 mg Hg/m{sup 3} for 30 min/day for 3 days a week. This exposure caused no toxic signs such as abnormal behavior or loss of body weight gain in the mice of either strain throughout the experimental period. Twenty-four hours after the termination of the exposure, mice were sacrificed and brain samples were subjected to mercury analysis, MT assay, and pathological examination. The MT-null mice showed lower accumulation of mercury in the brain than the wild type mice. Mercury exposure resulted in a 70% increase of brain MT in the wild type mice, which was mostly accounted for by the increase in MT-I/II. On the other hand, the brain MT in the MT-null mice increased by 19%, suggesting less reactivity of the MT-III gene to mercury vapor. Although histochemical examination revealed silver-mercury grains in the cytoplasm of nerve cells and glial cells throughout the brains of both strains, no significant difference was observed between the two strains. (orig.)

Magmatic-vapor expansion and the formation of high-sulfidation gold deposits: Chemical controls on alteration and mineralization

Science.gov (United States)

Henley, R.W.; Berger, B.R.

2011-01-01

Large bulk-tonnage high-sulfidation gold deposits, such as Yanacocha, Peru, are the surface expression of structurally-controlled lode gold deposits, such as El Indio, Chile. Both formed in active andesite-dacite volcanic terranes. Fluid inclusion, stable isotope and geologic data show that lode deposits formed within 1500. m of the paleo-surface as a consequence of the expansion of low-salinity, low-density magmatic vapor with very limited, if any, groundwater mixing. They are characterized by an initial 'Sulfate' Stage of advanced argillic wallrock alteration ?? alunite commonly with intense silicification followed by a 'Sulfide' Stage - a succession of discrete sulfide-sulfosalt veins that may be ore grade in gold and silver. Fluid inclusions in quartz formed during wallrock alteration have homogenization temperatures between 100 and over 500 ??C and preserve a record of a vapor-rich environment. Recent data for El Indio and similar deposits show that at the commencement of the Sulfide Stage, 'condensation' of Cu-As-S sulfosalt melts with trace concentrations of Sb, Te, Bi, Ag and Au occurred at > 600 ??C following pyrite deposition. Euhedral quartz crystals were simultaneously deposited from the vapor phase during crystallization of the vapor-saturated melt occurs to Fe-tennantite with progressive non-equilibrium fractionation of heavy metals between melt-vapor and solid. Vugs containing a range of sulfides, sulfosalts and gold record the changing composition of the vapor. Published fluid inclusion and mineralogical data are reviewed in the context of geological relationships to establish boundary conditions through which to trace the expansion of magmatic vapor from source to surface and consequent alteration and mineralization. Initially heat loss from the vapor is high resulting in the formation of acid condensate permeating through the wallrock. This Sulfate Stage alteration effectively isolates the expansion of magmatic vapor in subsurface fracture arrays

Application of vacuum metallurgy to separate pure metal from mixed metallic particles of crushed waste printed circuit board scraps.

Science.gov (United States)

Zhan, Lu; Xu, Zhenming

2008-10-15

The principle of separating pure metal from mixed metallic particles (MMPs) byvacuum metallurgy is that the vapor pressures of various metals at the same temperature are different As a result, the metal with high vapor pressure and low boiling point can be separated from the mixed metals through distillation or sublimation, and then it can be recycled through condensation under a certain condition. The vacuum metallurgy separation (VMS) of MMPs of crushed waste printed circuit boards (WPCBs) has been studied in this paper. Theoretical analyses show that the MMPs (copper, zinc, bismuth, lead, and indium, for example) can be separated by vacuum metallurgy. The copper particles (0.15-0.20 mm) and zinc particles (<0.30 mm) were chosen to simulate the MMPs of crushed WPCBs. Experimental results show that the separated efficiency of zinc in the copper-rich particles achieves 96.19 wt % when the vacuum pressure is 0.01-0.10 Pa, the heating temperature is 1123 K, and the heating time is 105 min. Under this operation condition, the separated efficiency of zinc in the copper-rich particles from crushed WPCBs achieves 97.00 wt % and the copper purity increases from 90.68 to 99.84 wt %.

Vaporization study on lanthanum-neodymium alloys by mass-spectrometry

International Nuclear Information System (INIS)

Shoji, Y.; Matsui, T.

1999-01-01

Partial vapor pressure of Nd(g) over La x Nd 1-x alloys (x = 0.10, 0.20, 0.30, 0.40, 0.50, 0.60, 0.70, 0.80 and 0.90) was measured with a time-of-flight mass-spectrometer equipped with a tungsten Knudsen cell over the temperature range of 1474-1767 K. Thermodynamic activity of neodymium in the liquid alloys was determined by comparing the partial vapor pressure of Nd(g) over the alloys with that over the pure metal. The thermodynamic activity of lanthanum in the alloys was calculated from that of neodymium obtained experimentally in this study by graphic integration using the Gibbs-Duhem equation. Both activities for each element, thus obtained, showed positive deviations from Raoult's law over the entire compositional range. Thermodynamic quantities such as Gibbs free energy of formation, excess enthalpy etc. were also calculated from the thermodynamic activities. (orig.)

Induction of Heavy-Metal-Transporting CPX-Type ATPases during Acid Adaptation in Lactobacillus bulgaricus▿

Science.gov (United States)

Penaud, S.; Fernandez, A.; Boudebbouze, S.; Ehrlich, S. D.; Maguin, E.; van de Guchte, M.

2006-01-01

Lactobacillus bulgaricus is a lactic acid bacteria (LAB) that, through the production of lactic acid, gradually acidifies its environment during growth. In the course of this process, L. bulgaricus acquires an improved tolerance to acidity. A survey of the recently established genome sequence shows that this bacterium possesses few of the pH control functions that have been described in other LAB and raises the question of what other mechanisms could be involved in its adaptation to the decreasing environmental pH. In some bacteria other than LAB, ion transport systems have been implicated in acid adaptation. We therefore studied the expression of this type of transport system during acid adaptation in L. bulgaricus by reverse transcription and real-time quantitative PCR and mapped transcription start sites. Intriguingly, the most significantly induced were three ATPases carrying the CPX signature of heavy-metal transporters. Protein homology and the presence of a conserved sequence motif in the promoter regions of the genes encoding these proteins strongly suggest that they are involved in copper homeostasis. Induction of this system is thought to assist in avoiding indirect damage that could result from medium acidification. PMID:16997986

Dynamics of vapor plume in transient keyhole during laser welding of stainless steel: Local evaporation, plume swing and gas entrapment into porosity

Science.gov (United States)

Pang, Shengyong; Chen, Xin; Shao, Xinyu; Gong, Shuili; Xiao, Jianzhong

2016-07-01

In order to better understand the local evaporation phenomena of keyhole wall, vapor plume swing above the keyhole and ambient gas entrapment into the porosity defects, the 3D time-dependent dynamics of the metallic vapor plume in a transient keyhole during fiber laser welding is numerically investigated. The vapor dynamical parameters, including the velocity and pressure, are successfully predicted and obtain good agreements with the experimental and literature data. It is found that the vapor plume flow inside the keyhole has complex multiple directions, and this various directions characteristic of the vapor plume is resulted from the dynamic evaporation phenomena with variable locations and orientations on the keyhole wall. The results also demonstrate that because of this dynamic local evaporation, the ejected vapor plume from the keyhole opening is usually in high frequency swinging. The results further indicate that the oscillation frequency of the plume swing angle is around 2.0-8.0 kHz, which is of the same order of magnitude with that of the keyhole depth (2.0-5.0 kHz). This consistency clearly shows that the swing of the ejected vapor plume is closely associated with the keyhole instability during laser welding. Furthermore, it is learned that there is usually a negative pressure region (several hundred Pa lower than the atmospheric pressure) of the vapor flow around the keyhole opening. This pressure could lead to a strong vortex flow near the rear keyhole wall, especially when the velocity of the ejected metallic vapor from the keyhole opening is high. Under the effect of this flow, the ambient gas is involved into the keyhole, and could finally be entrapped into the bubbles within a very short time (keyhole.

Vaporization study on vanadium monoxide and two-phase mixture of vanadium and vanadium monoxide by mass-spectrometric method

International Nuclear Information System (INIS)

Banchorndhevakul, W.; Matsui, Tsuneo; Naito, Keiji

1986-01-01

The vapor pressures over single phase vanadium monoxide VO 1.022 (s) and the two-phase mixture of vanadium metal (β phase) and vanadium monoxide were measured by mass-spectrometric method in the temperature range of 1,803 ∼ 1,990 and 1,703 ∼ 1,884 K, respectively. The main gas species over both systems were found to be VO(g) and V(g). The vapor pressure of VO(g) over the two-phase mixture of V(s) and VO(s) was a little lower than that over single phase VO(s). The vapor pressure of V(g) over the two-phase mixture was nearly equal to that over single phase. From the vapor pressure data, the enthalpies of vaporization, the enthalpies of formation for VO(g) and V(g) and the dissociation energy of VO(g) were determined. The oxygen partial pressure was calculated as a function of temperature from the vapor pressures of VO(g) and V(g), from which the partial molar enthalpies and entropies of oxygen in both systems were obtained. (author)

Atmospheric pressure plasma enhanced chemical vapor deposition of zinc oxide and aluminum zinc oxide

International Nuclear Information System (INIS)

Johnson, Kyle W.; Guruvenket, Srinivasan; Sailer, Robert A.; Ahrenkiel, S. Phillip; Schulz, Douglas L.

2013-01-01

Zinc oxide (ZnO) and aluminum-doped zinc oxide (AZO) thin films were deposited via atmospheric pressure plasma enhanced chemical vapor deposition. A second-generation precursor, bis(1,1,1,5,5,5-hexafluoro-2,4-pentanedionato)(N,N′-diethylethylenediamine) zinc, exhibited significant vapor pressure and good stability at one atmosphere where a vaporization temperature of 110 °C gave flux ∼ 7 μmol/min. Auger electron spectroscopy confirmed that addition of H 2 O to the carrier gas stream mitigated F contamination giving nearly 1:1 metal:oxide stoichiometries for both ZnO and AZO with little precursor-derived C contamination. ZnO and AZO thin film resistivities ranged from 14 to 28 Ω·cm for the former and 1.1 to 2.7 Ω·cm for the latter. - Highlights: • A second generation precursor was utilized for atmospheric pressure film growth. • Addition of water vapor to the carrier gas stream led to a marked reduction of ZnF 2 . • Carbonaceous contamination from the precursor was minimal

An induction-based magnetohydrodynamic 3D code for finite magnetic Reynolds number liquid-metal flows in fusion blankets

International Nuclear Information System (INIS)

Kawczynski, Charlie; Smolentsev, Sergey; Abdou, Mohamed

2016-01-01

Highlights: • A new induction-based magnetohydrodynamic code was developed using a finite difference method. • The code was benchmarked against purely hydrodynamic and MHD flows for low and finite magnetic Reynolds number. • Possible applications of the new code include liquid-metal MHD flows in the breeder blanket during unsteady events in the plasma. - Abstract: Most numerical analysis performed in the past for MHD flows in liquid-metal blankets were based on the assumption of low magnetic Reynolds number and involved numerical codes that utilized electric potential as the main electromagnetic variable. One limitation of this approach is that such codes cannot be applied to truly unsteady processes, for example, MHD flows of liquid-metal breeder/coolant during unsteady events in plasma, such as major plasma disruptions, edge-localized modes and vertical displacements, when changes in plasmas occur at millisecond timescales. Our newly developed code MOONS (Magnetohydrodynamic Object-Oriented Numerical Solver) uses the magnetic field as the main electromagnetic variable to relax the limitations of the low magnetic Reynolds number approximation for more realistic fusion reactor environments. The new code, written in Fortran, implements a 3D finite-difference method and is capable of simulating multi-material domains. The constrained transport method was implemented to evolve the magnetic field in time and assure that the magnetic field remains solenoidal within machine accuracy at every time step. Various verification tests have been performed including purely hydrodynamic flows and MHD flows at low and finite magnetic Reynolds numbers. Test results have demonstrated very good accuracy against known analytic solutions and other numerical data.

An induction-based magnetohydrodynamic 3D code for finite magnetic Reynolds number liquid-metal flows in fusion blankets

Energy Technology Data Exchange (ETDEWEB)

Kawczynski, Charlie; Smolentsev, Sergey, E-mail: sergey@fusion.ucla.edu; Abdou, Mohamed

2016-11-01

Highlights: • A new induction-based magnetohydrodynamic code was developed using a finite difference method. • The code was benchmarked against purely hydrodynamic and MHD flows for low and finite magnetic Reynolds number. • Possible applications of the new code include liquid-metal MHD flows in the breeder blanket during unsteady events in the plasma. - Abstract: Most numerical analysis performed in the past for MHD flows in liquid-metal blankets were based on the assumption of low magnetic Reynolds number and involved numerical codes that utilized electric potential as the main electromagnetic variable. One limitation of this approach is that such codes cannot be applied to truly unsteady processes, for example, MHD flows of liquid-metal breeder/coolant during unsteady events in plasma, such as major plasma disruptions, edge-localized modes and vertical displacements, when changes in plasmas occur at millisecond timescales. Our newly developed code MOONS (Magnetohydrodynamic Object-Oriented Numerical Solver) uses the magnetic field as the main electromagnetic variable to relax the limitations of the low magnetic Reynolds number approximation for more realistic fusion reactor environments. The new code, written in Fortran, implements a 3D finite-difference method and is capable of simulating multi-material domains. The constrained transport method was implemented to evolve the magnetic field in time and assure that the magnetic field remains solenoidal within machine accuracy at every time step. Various verification tests have been performed including purely hydrodynamic flows and MHD flows at low and finite magnetic Reynolds numbers. Test results have demonstrated very good accuracy against known analytic solutions and other numerical data.

Preconcentration of heavy metals on activated carbon and their determination in fruits by inductively coupled plasma optical emission spectrometry.

Science.gov (United States)

Feist, Barbara; Mikula, Barbara

2014-03-15

A method of separation and preconcentration of cadmium, cobalt, copper, nickel, lead, and zinc at trace level using activated carbon is proposed. Activated carbon with the adsorbed trace metals was mineralised using a high-pressure microwave mineraliser. The heavy metals were determined after preconcentration by inductively coupled plasma optical emission spectrometry (ICP-OES). The influence of several parameters, such as pH, sorbent mass, shaking time was examined. Moreover, effects of inorganic matrix on recovery of the determined elements were studied. The experiment shows that foreign ions did not influence recovery of the determined elements. The detection limits (DL) of Cd, Co, Cu, Ni, Pb, and Zn were 0.17, 0.19, 1.60, 2.60, 0.92 and 1.50 μg L(-)(1), respectively. The recovery of the method for the determined elements was better than 95% with relative standard deviation from 1.3% to 3.7%. The preconcentration factor was 80. The proposed method was applied for determination of Cd, Co, Cu, Ni, Pb, and Zn in fruits materials. Accuracy of the proposed method was verified using certified reference material (NCS ZC85006 Tomato). Copyright © 2013 Elsevier Ltd. All rights reserved.

Slurry sampling flow injection chemical vapor generation inductively coupled plasma mass spectrometry for the determination of trace Ge, As, Cd, Sb, Hg and Bi in cosmetic lotions

Energy Technology Data Exchange (ETDEWEB)

Chen, Wei-Ni [Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (China); Jiang, Shiuh-Jen, E-mail: sjjiang@faculty.nsysu.edu.tw [Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (China); Department of Medical Laboratory Science and Biotechnology, Kaohsiung Medical University, Kaohsiung 80708, Taiwan (China); Chen, Yen-Ling [Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, Kaohsiung 80708, Taiwan (China); Sahayam, A.C. [National Centre for Compositional Characterisation of Materials (CCCM), Hyderabad (India)

2015-02-20

Highlights: • Determination of Ge, As, Cd, Sb, Hg and Bi in cosmetic lotions in a single run. • Accurate analysis using isotope dilution and standard addition methods. • Vapor generation ICP-MS yielded superior detection limits compared to ETV-ICP-MS. • No sample dissolution increased sample through put. • Analysis of GBW09305 Cosmetic (Cream) reference material for accuracy. - Abstract: A slurry sampling inductively coupled plasma mass spectrometry (ICP-MS) method has been developed for the determination of Ge, As, Cd, Sb, Hg and Bi in cosmetic lotions using flow injection (FI) vapor generation (VG) as the sample introduction system. A slurry containing 2% m/v lotion, 2% m/v thiourea, 0.05% m/v L-cysteine, 0.5 μg mL{sup −1} Co(II), 0.1% m/v Triton X-100 and 1.2% v/v HCl was injected into a VG-ICP-MS system for the determination of Ge, As, Cd, Sb, Hg and Bi without dissolution and mineralization. Because the sensitivities of the analytes in the slurry and that of aqueous solution were quite different, an isotope dilution method and a standard addition method were used for the determination. This method has been validated by the determination of Ge, As, Cd, Sb, Hg and Bi in GBW09305 Cosmetic (Cream) reference material. The method was also applied for the determination of Ge, As, Cd, Sb, Hg and Bi in three cosmetic lotion samples obtained locally. The analysis results of the reference material agreed with the certified value and/or ETV-ICP-MS results. The detection limit estimated from the standard addition curve was 0.025, 0.1, 0.2, 0.1, 0.15, and 0.03 ng g{sup −1} for Ge, As, Cd, Sb, Hg and Bi, respectively, in original cosmetic lotion sample.

Slurry sampling flow injection chemical vapor generation inductively coupled plasma mass spectrometry for the determination of trace Ge, As, Cd, Sb, Hg and Bi in cosmetic lotions

International Nuclear Information System (INIS)

Chen, Wei-Ni; Jiang, Shiuh-Jen; Chen, Yen-Ling; Sahayam, A.C.

2015-01-01

Highlights: • Determination of Ge, As, Cd, Sb, Hg and Bi in cosmetic lotions in a single run. • Accurate analysis using isotope dilution and standard addition methods. • Vapor generation ICP-MS yielded superior detection limits compared to ETV-ICP-MS. • No sample dissolution increased sample through put. • Analysis of GBW09305 Cosmetic (Cream) reference material for accuracy. - Abstract: A slurry sampling inductively coupled plasma mass spectrometry (ICP-MS) method has been developed for the determination of Ge, As, Cd, Sb, Hg and Bi in cosmetic lotions using flow injection (FI) vapor generation (VG) as the sample introduction system. A slurry containing 2% m/v lotion, 2% m/v thiourea, 0.05% m/v L-cysteine, 0.5 μg mL −1 Co(II), 0.1% m/v Triton X-100 and 1.2% v/v HCl was injected into a VG-ICP-MS system for the determination of Ge, As, Cd, Sb, Hg and Bi without dissolution and mineralization. Because the sensitivities of the analytes in the slurry and that of aqueous solution were quite different, an isotope dilution method and a standard addition method were used for the determination. This method has been validated by the determination of Ge, As, Cd, Sb, Hg and Bi in GBW09305 Cosmetic (Cream) reference material. The method was also applied for the determination of Ge, As, Cd, Sb, Hg and Bi in three cosmetic lotion samples obtained locally. The analysis results of the reference material agreed with the certified value and/or ETV-ICP-MS results. The detection limit estimated from the standard addition curve was 0.025, 0.1, 0.2, 0.1, 0.15, and 0.03 ng g −1 for Ge, As, Cd, Sb, Hg and Bi, respectively, in original cosmetic lotion sample

Enthalpy of vaporization and vapor pressure of whiskey lactone and menthalactone by correlation gas chromatography

International Nuclear Information System (INIS)

Simmons, Daniel; Chickos, James

2017-01-01

Highlights: • The vapor pressure and vaporization enthalpies of cis and trans-whiskey lactone have been evaluated. • Enthalpies of vaporization and vapor pressures of (+)-isomintlactone and (−)-mintlactone were also evaluated. • The sublimation enthalpy and corresponding vapor pressure of (+) -isomintlactone at T = 298.15 K is estimated. - Abstract: Enthalpies of vaporization at T = 298.15 K of cis and trans-whiskey lactone have been evaluated by correlation gas chromatography to be (68.4 ± 1.7) kJ·mol −1 and (67.5 ± 1.7) kJ·mol −1 , respectively. The enthalpies of vaporization of isomintlactone and mintlactone also evaluated by correlation gas chromatography have been found to have vaporization enthalpies of (74.2 ± 1.8) kJ·mol −1 and (73.2 ± 1.8) kJ·mol −1 respectively. The vapor pressures for cis and trans-whiskey lactone at T = 298.15 K have been evaluated as (1.5 ± 0.09) Pa and (2.0 ± 0.1) Pa using vapor pressures of a series of lactones as standards. Vapor pressures for isomintlactone and mintlactone were evaluated as (0.26 ± 0.012) Pa and (0.33 ± 0.02) Pa, respectively. Fusion and sublimation enthalpies for (+)-isomintlactone as well as the vapor pressure of the solid have been estimated.

ZnO Nanowires Synthesized by Vapor Phase Transport Deposition on Transparent Oxide Substrates

Directory of Open Access Journals (Sweden)

Taylor Curtis

2010-01-01

Full Text Available Abstract Zinc oxide nanowires have been synthesized without using metal catalyst seed layers on fluorine-doped tin oxide (FTO substrates by a modified vapor phase transport deposition process using a double-tube reactor. The unique reactor configuration creates a Zn-rich vapor environment that facilitates formation and growth of zinc oxide nanoparticles and wires (20–80 nm in diameter, up to 6 μm in length, density <40 nm apart at substrate temperatures down to 300°C. Electron microscopy and other characterization techniques show nanowires with distinct morphologies when grown under different conditions. The effect of reaction parameters including reaction time, temperature, and carrier gas flow rate on the size, morphology, crystalline structure, and density of ZnO nanowires has been investigated. The nanowires grown by this method have a diameter, length, and density appropriate for use in fabricating hybrid polymer/metal oxide nanostructure solar cells. For example, it is preferable to have nanowires no more than 40 nm apart to minimize exciton recombination in polymer solar cells.

Raman scattering studies of YBa2Cu3O7-x thin films grown by chemical vapor deposition and metal-organic deposition

International Nuclear Information System (INIS)

Lee, E.; Yoon, S.; Um, Y.M.; Jo, W.; Seo, C.W.; Cheong, H.; Kim, B.J.; Lee, H.G.; Hong, G.W.

2007-01-01

We present results of Raman scattering studies of superconducting YBa 2 Cu 3 O 7-x (YBCO) films grown by chemical vapor deposition and metal-organic deposition methods. It is shown by X-ray diffraction that all the as-grown YBCO films have a highly c-axis oriented and in-plane aligned texture. Raman scattering measurements were used to investigate optical phonon modes, oxygen contents, structural properties, and second-phases of the YBCO coated conductors. Raman spectra of YBCO films with lower-transport qualities exhibit additional phonon modes at ∼300 cm -1 , ∼600 cm -1 , and ∼630 cm -1 , which are related to second-phases such as Ba 2 Cu 3 O 5.9 and BaCuO 2 . Our results strongly suggest that Raman scattering be useful for optimizing YBCO film growth conditions

Optimization of processing parameters in induction hardening using ...

Indian Academy of Sciences (India)

Technology, Kabir Nagar, Jalandhar City, Punjab 144 008, India ... applied design of experiment and neural network approach in case of the induction ... Lai et al (2009) studied large-sized slewing bearings sub- ..... Miller D A and Lagoudas D C 1980 Trends in the development of heat-treatment technology, J. Metal.

Influence of the temperature, volume and type of solution in the mercury vaporization of dental amalgam residue

Energy Technology Data Exchange (ETDEWEB)

Costa, Raquel dalla [Department of Chemical Engineering, State University of Maringa, Maringa - PR (Brazil)], E-mail: raqueldc_eng@yahoo.com.br; Cossich, Eneida Sala; Tavares, Celia Regina Granhen [Department of Chemical Engineering, State University of Maringa, Maringa - PR (Brazil)

2008-12-15

One of the qualitative methods for the identification of mercury vapor is what it occurs as a way of chemical reaction between palladium chloride and metallic mercury. Palladium chloride ribbons with yellowish coloration put in contact with the vaporized mercury of dental amalgam residue, liberates palladium and forms mercury chloride in your surface, and starts to have black coloration; this form identify the presence of the mercury vapor in the system. This work studies the influence of temperature, volume and type of barrier-solution in the vaporization of mercury during the period of storage of dental amalgam residues, aiming to establish the best conditions for storage of these residues. It was found that for all tested solutions, the longest storage times without any occurrence of mercury vaporization were obtained in the lowest temperatures tested and the largest solution volumes of barrier-solution. The radiographic effluent presented bigger efficacy in the reduction of the volatilization, increasing the period when the residue was stored, however the analysis of this solution after the vaporization test showed the presence of organic mercury. These results show that water is the most efficient barrier against the vaporization of mercury, since it did not result in organic mercury formation in the effluent solution from the storage process.

Influence of the temperature, volume and type of solution in the mercury vaporization of dental amalgam residue

International Nuclear Information System (INIS)

Costa, Raquel dalla; Cossich, Eneida Sala; Tavares, Celia Regina Granhen

2008-01-01

One of the qualitative methods for the identification of mercury vapor is what it occurs as a way of chemical reaction between palladium chloride and metallic mercury. Palladium chloride ribbons with yellowish coloration put in contact with the vaporized mercury of dental amalgam residue, liberates palladium and forms mercury chloride in your surface, and starts to have black coloration; this form identify the presence of the mercury vapor in the system. This work studies the influence of temperature, volume and type of barrier-solution in the vaporization of mercury during the period of storage of dental amalgam residues, aiming to establish the best conditions for storage of these residues. It was found that for all tested solutions, the longest storage times without any occurrence of mercury vaporization were obtained in the lowest temperatures tested and the largest solution volumes of barrier-solution. The radiographic effluent presented bigger efficacy in the reduction of the volatilization, increasing the period when the residue was stored, however the analysis of this solution after the vaporization test showed the presence of organic mercury. These results show that water is the most efficient barrier against the vaporization of mercury, since it did not result in organic mercury formation in the effluent solution from the storage process

Preparation of Hydrophobic Metal-Organic Frameworks via Plasma Enhanced Chemical Vapor Deposition of Perfluoroalkanes for the Removal of Ammonia

Science.gov (United States)

DeCoste, Jared B.; Peterson, Gregory W.

2013-01-01

Plasma enhanced chemical vapor deposition (PECVD) of perfluoroalkanes has long been studied for tuning the wetting properties of surfaces. For high surface area microporous materials, such as metal-organic frameworks (MOFs), unique challenges present themselves for PECVD treatments. Herein the protocol for development of a MOF that was previously unstable to humid conditions is presented. The protocol describes the synthesis of Cu-BTC (also known as HKUST-1), the treatment of Cu-BTC with PECVD of perfluoroalkanes, the aging of materials under humid conditions, and the subsequent ammonia microbreakthrough experiments on milligram quantities of microporous materials. Cu-BTC has an extremely high surface area (~1,800 m2/g) when compared to most materials or surfaces that have been previously treated by PECVD methods. Parameters such as chamber pressure and treatment time are extremely important to ensure the perfluoroalkane plasma penetrates to and reacts with the inner MOF surfaces. Furthermore, the protocol for ammonia microbreakthrough experiments set forth here can be utilized for a variety of test gases and microporous materials. PMID:24145623

Evaluation of slurry preparation procedures for the determination of mercury by axial view inductively coupled plasma optical emission spectrometry using on-line cold vapor generation

International Nuclear Information System (INIS)

Santos, Eder Jose dos; Herrmann, Amanda Beatriz; Antunes Vieira, Mariana; Azzolin Frescura, Vera Lucia; Curtius, Adilson Jose

2005-01-01

Five different slurry preparation procedures were tested, after grinding the solid samples to a particle size ≤53 μm: (1) using aqua regia plus HF, 30 min of sonication, standing time of 24 h followed by another 30 min of sonication; (2) same as the previous one, except that the standing time and the second ultrasound treatment were omitted; (3) same as the previous one, except that HF was not used; (4) same as the previous one, except that the aqua regia was replaced by nitric acid; (5) same as the previous one, except that the acid nitric was replaced by tetramethylammonium hydroxide (TMAH). The Hg vapor was generated on-line, and the emission signal intensity measured at 253.652 nm by axial view inductively coupled plasma optical emission spectrometry. Initially, four experimental conditions were optimized using a multivariate factorial analysis: the concentrations of HCl and of the reducing agent, NaBH 4 , used in the cold vapor generation, and two instrumental parameters, the plasma radiofrequency power and the carrier gas flow rate. The radiofrequency power was statistically significant, but limited to 1.2 kW for practical reasons. The procedures were applied to 11 biological and environmental materials. Both, the slurries and the filtrates were analyzed, using calibration solutions in the same medium as in the slurries. The first three procedures produced results in agreement with the certified values. The two last procedures, using nitric acid or TMHA could not be used for quantitative analysis. For practical reasons, Procedure 3, with a detection limit (3s, n=10) of 0.06 μg g -1 for a sample mass of 20 mg in a final volume of 15 mL is recommended. The relative standard deviations for mercury in the investigated materials, using the recommended procedure, were lower than 12.5%, indicating a good precision for slurry sampling. The recommended procedure is simple, rapid and robust

Determination of Cd, Hg, Pb and Tl in coal and coal fly ash slurries using electrothermal vaporization inductively coupled plasma mass spectrometry and isotopic dilution

Energy Technology Data Exchange (ETDEWEB)

Maia, S.M.; Pozebon, D.; Curtius, A.J. [Univ. Federal de Santa Catarina, Florianopolis, SC (Brazil)

2003-07-01

A method has been investigated for the determination of Cd, Hg, Pb and Tl in coal and in coal fly ash, using slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry and isotope dilution. The slurry, 25 mg ml{sup -1}, was prepared by mixing the powdered sample (less than or equal to 36 - 45 mm) with acid solutions (nitric acid for coal and nitric and hydrofluoric acids for coal fly ash) and submitting the mixture to an ultrasonic agitation, letting it stand afterwards in a water bath at 60{sup o}C for 2 h. An ultrasonic probe was used to homogenize the slurry in the autosampler cup just before its introduction into the graphite tube. The best conditions were determined regarding analyte sensitivity, furnace temperature program, amount of modifier, acid concentration, gas flow rate and particle size. For Hg, the pyrolysis stage was omitted and a low vaporization temperature was used (450 - 1000{sup o}C); the residual matrix was eliminated in the first step of the following cycle. The modifiers used were: Pd for Cd and Tl; Au, Ir or Pd for Hg; Ir or Pd for Pb. The accuracy of the method was checked by analyzing six certified coal reference materials (SARM 20, SARM 19, BCR No. 40, BCR No. 180, BCR No. 181 and NIST 1630a) and one certified coal fly ash (NIST 1633b). With one exception (Hg in BCR No. 180), the found concentrations were typically within 95% confidence interval of the certified values, or close enough to the recommended values, as long as the samples were ground to a small enough particle size. The limits of detection were typically around 0.08 {mu}g g{sup -1}, 0.03 {mu}g g{sup -1}, 1 {mu}g g{sup -1} and 0.02 {mu}g g{sup -1} for Cd, Hg, Pb and Tl, respectively. The precision was also adequate with relative standard deviations of usually < 5%.

Chemical metallization of KMPR photoresist polymer in aqueous solutions

Science.gov (United States)

Zeb, Gul; Duong, Xuan Truong; Vu, Ngoc Pi; Phan, Quang The; Nguyen, Duc Tuong; Ly, Viet Anh; Salimy, Siamak; Le, Xuan Tuan

2017-06-01

While conventional methods for preparing thin films of metals and metallic alloys on insulating substrates in the field of microelectromechanical systems (MEMS) include vapor deposition techniques, we demonstrate here that electroless deposition can be considered as an alternate efficient approach to metallize the surface of insulating substrates, such as KMPR epoxy photoresist polymer. In comparison with the physical and chemical vapor deposition methods, which are well-established for metallization of photoresist polymers, our electroless nickel plating requires only immersing the substrates into aqueous solutions in open air at low temperatures. Thin films of nickel alloy have been deposited electrolessly on KMPR surface, through a cost-effective and environmental chromium-free process, mediated through direct grafting of amine palladium complexes in aqueous medium. This covalent organic coating provides excellent adhesion between KMPR and the nickel film and allows better control of the palladium catalyst content. Covalent grafting and characterization of the deposited nickel film have been carried out by means of Fourier-transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy techniques.

Experiences of marijuana-vaporizer users.

Science.gov (United States)

Malouff, John M; Rooke, Sally E; Copeland, Jan

2014-01-01

Using a marijuana vaporizer may have potential harm-reduction advantages on smoking marijuana, in that the user does not inhale smoke. Little research has been published on use of vaporizers. In the first study of individuals using a vaporizer on their own initiative, 96 adults anonymously answered questions about their experiences with a vaporizer and their use of marijuana with tobacco. Users identified 4 advantages to using a vaporizer over smoking marijuana: perceived health benefits, better taste, no smoke smell, and more effect from the same amount of marijuana. Users identified 2 disadvantages: inconvenience of setup and cleaning and the time it takes to get the device operating for each use. Only 2 individuals combined tobacco in the vaporizer mix, whereas 15 combined tobacco with marijuana when they smoked marijuana. Almost all participants intended to continue using a vaporizer. Vaporizers seem to have appeal to marijuana users, who perceive them as having harm-reduction and other benefits. Vaporizers are worthy of experimental research evaluating health-related effects of using them.

Reversible light-controlled conductance switching of azobenzene-based metal/polymer nanocomposites

International Nuclear Information System (INIS)

Pakula, Christina; Zaporojtchenko, Vladimir; Strunskus, Thomas; Faupel, Franz; Zargarani, Dordaneh; Herges, Rainer

2010-01-01

We present a new concept of light-controlled conductance switching based on metal/polymer nanocomposites with dissolved chromophores that do not have intrinsic current switching ability. Photoswitchable metal/PMMA nanocomposites were prepared by physical vapor deposition of Au and Pt clusters, respectively, onto spin-coated thin poly(methylmethacrylate) films doped with azo-dye molecules. High dye concentrations were achieved by functionalizing the azo groups with tails and branches, thus enhancing solubility. The composites show completely reversible optical switching of the absorption bands upon alternating irradiation with UV and blue light. We also demonstrate reversible light-controlled conductance switching. This is attributed to changes in the metal cluster separation upon isomerization based on model experiments where analogous conductance changes were induced by swelling of the composite films in organic vapors and by tensile stress.

The effect of atoms excited by electron beam on metal evaporation

CERN Document Server

Xie Guo Feng; Ying Chun Tong

2002-01-01

In atomic vapor laser isotope separation (AVLIS), the metal is heated to melt by electron beams. The vapor atoms may be excited by electrons when flying through the electron beam. The excited atoms may be deexcited by inelastic collision during expansion. The electronic energy transfers translational energy. In order to analyse the effect of reaction between atoms and electron beams on vapor physical parameters, such as density, velocity and temperature, direct-simulation Monte Carlo method (DSMC) is used to simulate the 2-D gadolinium evaporation from long and narrow crucible. The simulation results show that the velocity and temperature of vapor increase, and the density decreases

Determination of some inorganic metals in edible vegetable oils by inductively coupled plasma atomic emission spectroscopy (ICP-AES

Directory of Open Access Journals (Sweden)

Musa Özcan, M.

2008-09-01

Full Text Available Seventeen edible vegetable oils were analyzed spectrometrically for their metal (Cu, Fe, Mn, Co, Cr, Pb, Cd, Ni, and Zn contents. Toxic metals in edible vegetable oils were determined by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES. The highest metal concentrations were measured as 0.0850, 0.0352, 0.0220, 0.0040, 0.0010, 0.0074, 0.0045, 0.0254 and 0.2870 mg/kg for copper in almond oil, for iron in corn oil-(c, for manganese in soybean oil, for cobalt in sunflower oil-(b and almond oil, for chromium in almond oil, for lead in virgin olive oil, for cadmium in sunflower oil-(e, for nickel almond oil and for zinc in almond oil respectively. The method for determining toxic metals in edible vegetable oils by using ICP-AES is discussed. The metals were extracted from low quantities of oil (2-3 g with a 10% nitric acid solution. The extracted metal in acid solution can be injected into the ICPAES. The proposed method is simple and allows the metals to be determined in edible vegetable oils with a precision estimated below 10% relative standard deviation (RSD for Cu, 5% for Fe, 15% for Mn, 8% for Co, 10% for Cr, 20% for Pb, 5% for Cd, 16% for Ni and 11% for Zn.En este estudio se analizó espectrométricamente el contenido en metales (Cu, Fe, Mn, Co, Cr, Pb, Cd, Ni, and Zn de 17 aceites vegetales comestibles mediante ICP-AES. Las concentaciones más elevadas se encontraron para el cobre en el aceite de almendra (0.0850 mg/kg, para el hierro en el aceite de maiz(c,(0.0352 mg/kg, para el manganeso en el aceite de soja (0.0220 mg/kg, para el cobalto en el aceite de girasol (b (0.0040 mg/kg, para el cromo en el aceite de almendra (0.0010 mg/kg, para el plomo en el aceite de oliva virgen (0.0074 mg/kg, para el cadmio en el aceite de girasol (e (0.0045 mg/kg, para el niquel en el aceite de almendra (0.0254 mg/kg y para el zincen el aceite de almendra (0.2870 mg/kg. Los metales se extrajeron a partir de bajas cantidades de aceite (2-3 g, con

Metallic Contact Formation for Molecular Electronics : Interactions between Vapor-Deposited Metals and Self-Assembled Monolayers of Conjugated Mono- and Dithiols

NARCIS (Netherlands)

Boer, Bert de; Frank, Martin M.; Chabal, Yves J.; Jiang, Weirong; Garfunkel, Eric; Bao, Zhenan

2004-01-01

We present grazing-incidence Fourier transform infrared and AFM data of Au, Al, and Ti vapor-deposited onto self-assembled monolayers (SAMs) of conjugated mono- and dithiols. SAMs of 4,4'''-dimercapto-p-quaterphenyl, 4,4''-dimercapto-p-terphenyl, and 4,4'-dimercapto-p-biphenyl have reactive thiols

In-depth agglomeration of d-metals at Si-on-Mo interfaces

NARCIS (Netherlands)

T. Tsarfati,; Zoethout, E.; van de Kruijs, R.; F. Bijkerk,

2009-01-01

Reflective Si/Mo multilayer mirrors with protective d-metal surfaces onto a range of upper Mo and Si layer thicknesses have been grown with physical vapor deposition and investigated on diffusion and in-depth compound formation. Laterally inhomogeneous upward Si and downward d-metal diffusion occurs

Metallic vapor supplying by the electron bombardment for a metallic ion production with an ECR ion source

Energy Technology Data Exchange (ETDEWEB)

Kitagawa, Atsushi; Sasaki, Makoto; Muramatsu, Masayuki [National Inst. of Radiological Sciences, Chiba (Japan); Jincho, Kaoru; Sasaki, Noriyuki; Sakuma, Tetsuya; Takasugi, Wataru; Yamamoto, Mitsugu [Accelerator Engineering Corporation, Chiba (Japan)

2001-11-19

To produce the metallic ion beam for the injection into the Heavy Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Sciences (NIRS), a new gas supply method has been developed for an 18 GHz ECR ion source (NIRS-HEC). A metallic target rod at a high positive potential is melted by the electron bombardment technique. The evaporated gas with a maximum flow rate of 50A/sec is supplied into the ECR plasma in case of Fe metal. (author)

Metallic vapor supplying by the electron bombardment for a metallic ion production with an ECR ion source

International Nuclear Information System (INIS)

Kitagawa, Atsushi; Sasaki, Makoto; Muramatsu, Masayuki; Jincho, Kaoru; Sasaki, Noriyuki; Sakuma, Tetsuya; Takasugi, Wataru; Yamamoto, Mitsugu

2001-01-01

To produce the metallic ion beam for the injection into the Heavy Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Sciences (NIRS), a new gas supply method has been developed for an 18 GHz ECR ion source (NIRS-HEC). A metallic target rod at a high positive potential is melted by the electron bombardment technique. The evaporated gas with a maximum flow rate of 50A/sec is supplied into the ECR plasma in case of Fe metal. (author)

Metal Detector By Using PIC Microcontroller Interfacing With PC

OpenAIRE

Yin Min Theint; Myo Maung Maung; Hla Myo Tun

2015-01-01

Abstract This system proposes metal detector by using PIC microcontroller interfacing with PC. The system uses PIC microcontroller as the main controller whether the detected metal is ferrous metal or non-ferrous metal. Among various types of metal sensors and various types of metal detecting technologies concentric type induction coil sensor and VLF very low frequency metal detecting technology are used in this system. This system consists of two configurations Hardware configuration and Sof...

Zirconium based bulk metallic glasses

International Nuclear Information System (INIS)

Dey, G.K.; Neogy, S.; Savalia, R.T.; Tewari, R.; Srivastava, D.; Banerjee, S.

2006-01-01

Metallic glasses have come into prominence in recent times because their nanocrystalline atomic arrangement imparts many useful and unusual properties to these metallic solids. In this study, bulk glasses have been obtained in Zr based multicomponent alloy by induction melting these alloys in silica crucibles and casting these in form of rods 3 and 6 mm in diameter in a copper mould

Method validation for determination of metals in Vitis labrusca L. grapevine leaf extracts by inductively coupled plasma mass spectrometry (ICP-MS

Directory of Open Access Journals (Sweden)

LIANE V.V. BOKOWSKI

Full Text Available ABSTRACT Vitis labrusca L. is the main species used for wine and juice production in Brazil. The grapevine leaves can be used both as functional foods and as cheapest sources for the extraction of phenolic compounds. Besides the antioxidant activity, grapevine leaves exhibited significant anti-inflammatory activity. Therefore, the aim of this study was to develop and validate an analytical methodology to determine the metals selenium (96Se, chromium (53Cr, nickel (62Ni, cadmium (111Cd and lead (206Pb in 30 samples of grapevine leaf extracts (Vitis labrusca, Bordo cultivar using inductively coupled plasma mass spectrometry (ICP-MS. To obtain the grapevine leaf extracts the samples were milled, weighed and digested in microwave oven with nitric acid. The method showed linearity, precision, accuracy and limits of quantification and detection acceptable for INMETRO protocol validation of analytical methods. Therefore, the method using ICP-MS was developed and validated to determine metals concentrations in grapevine leaves of Vitis labrusca L. and the proposed method could be applied in routine analytical laboratory.

Metals on graphene and carbon nanotube surfaces: From mobile atoms to atomtronics to bulk metals to clusters and catalysts

KAUST Repository

Sarkar, Santanu C.; Moser, Matthew L.; Tian, Xiaojuan; Zhang, Xixiang; Al-Hadeethi, Yas Fadel; Haddon, Robert C.

2014-01-01

, and the next generation energy devices. We touch on chemical vapor deposition (CVD) graphene grown on metals, the reactivity of its surface, and its use as a template for asymmetric graphene functionalization chemistry (ultrathin Janus discs). We highlight some

Prospects for trivalent rare earth molecular vapor lasers for fusion

International Nuclear Information System (INIS)

Krupke, W.F.

1976-01-01

The dynamical properties of three types of RE 3+ molecular vapors were considered: (1) rare earth trihalogens, (2) rare earth trihalogens complexed with transition metal trihalogens, and (3) rare earth chelates. Radiative and nonradiative (unimolecular and bimolecular) transition probabilities have been calculated using phenomenological models predicted on the unique electronic structure of the triply ionized RE ion (well shielded ground electronic configuration of equivalent of electrons). Although all the lanthanide ions have been treated in some detail, specific results are presented for the Nd 3+ and Tb 3+ ions to illustrate the systematics of these vapors as a class of new laser media. Once verified, these phenomenological models will provide a powerful tool for the directed experimental exploration of these systems. Because of the structural similarity to the triply ionized actinides, comments offered here for the lanthanide rare earth series generally apply to gaseous actinide lasers which are also under consideration

Fate of alkali and trace metals in biomass gasification

International Nuclear Information System (INIS)

Salo, K.; Mojtahedi, W.

1998-01-01

The fate of alkali metals (Na, K) and eleven toxic trace elements (Hg, Cd, Be, Se, Sb, As, Pb, Zn, Cr, Co, Ni) in biomass gasification have been extensively investigated in Finland in the past ten years. The former due to the gas turbine requirements and the latter to comply with environmental regulations. In this paper the results of several experimental studies to measure Na and K in the vapor phase after the gas cooler of a simplified (air-blown) Integrated Gasification Combined-Cycle (IGCC) system are reported. Also, trace element emissions from an IGCC plant using alfalfa as the feedstock are discussed and the concentration of a few toxic trace metals in the vapor phase in the gasifier product gas are reported. (author)

Waste Tank Vapor Project: Tank vapor database development

International Nuclear Information System (INIS)

Seesing, P.R.; Birn, M.B.; Manke, K.L.

1994-09-01

The objective of the Tank Vapor Database (TVD) Development task in FY 1994 was to create a database to store, retrieve, and analyze data collected from the vapor phase of Hanford waste tanks. The data needed to be accessible over the Hanford Local Area Network to users at both Westinghouse Hanford Company (WHC) and Pacific Northwest Laboratory (PNL). The data were restricted to results published in cleared reports from the laboratories analyzing vapor samples. Emphasis was placed on ease of access and flexibility of data formatting and reporting mechanisms. Because of time and budget constraints, a Rapid Application Development strategy was adopted by the database development team. An extensive data modeling exercise was conducted to determine the scope of information contained in the database. a A SUN Sparcstation 1000 was procured as the database file server. A multi-user relational database management system, Sybase reg-sign, was chosen to provide the basic data storage and retrieval capabilities. Two packages were chosen for the user interface to the database: DataPrism reg-sign and Business Objects trademark. A prototype database was constructed to provide the Waste Tank Vapor Project's Toxicology task with summarized and detailed information presented at Vapor Conference 4 by WHC, PNL, Oak Ridge National Laboratory, and Oregon Graduate Institute. The prototype was used to develop a list of reported compounds, and the range of values for compounds reported by the analytical laboratories using different sample containers and analysis methodologies. The prototype allowed a panel of toxicology experts to identify carcinogens and compounds whose concentrations were within the reach of regulatory limits. The database and user documentation was made available for general access in September 1994

The vapor pressures of explosives

Energy Technology Data Exchange (ETDEWEB)

Ewing, Robert G.; Waltman, Melanie J.; Atkinson, David A.; Grate, Jay W.; Hotchkiss, Peter

2013-01-05

The vapor pressures of many explosive compounds are extremely low and thus determining accurate values proves difficult. Many researchers, using a variety of methods, have measured and reported the vapor pressures of explosives compounds at single temperatures, or as a function of temperature using vapor pressure equations. There are large variations in reported vapor pressures for many of these compounds, and some errors exist within individual papers. This article provides a review of explosive vapor pressures and describes the methods used to determine them. We have compiled primary vapor pressure relationships traceable to the original citations and include the temperature ranges for which they have been determined. Corrected values are reported as needed and described in the text. In addition, after critically examining the available data, we calculate and tabulate vapor pressures at 25 °C.

Separation of magnesium from magnesium chloride and zirconium and/or hafnium subchlorides in the production of zirconium and/or hafnium sponge metal

International Nuclear Information System (INIS)

Abodishish, H.A.M.; Adams, R.J.; Kearl, S.R.

1992-01-01

This patent describes the producing of a refractory metal wherein a sponge refractory metal is produced as an intermediate product by the use of magnesium with the incidental production of magnesium chloride, and wherein residual magnesium is separated from the magnesium chloride and from refractory metal to a vacuum distillation step which fractionally distills the magnesium, the magnesium chloride, and the metal sub-chlorides; the steps of: recovering fractionally distilled vapors of magnesium chloride and metal sub-chlorides from a sponge refractory metal; separately condensing the vapors as separately recovered; and recycling the separately recovered magnesium at a purity of at least about 96%

Inductive Cross Shaped Metal Meshes in Silicon Substrate

National Research Council Canada - National Science Library

Sternberg, O; Moller, K. D; Grebel, H; Stewart, K. P; Henry, R. M

2002-01-01

.... The Micro-Stripes program was used for the calculation of resonance wavelength and width of resonance of cross shaped metal meshes and best- fit formulas were developed for the presentation of the data...

Metallic coating of microspheres

International Nuclear Information System (INIS)

Meyer, S.F.

1980-01-01

Extremely smooth, uniform metal coatings of micrometer thicknesses on microscopic glass spheres (microspheres) are often needed as targets for inertial confinement fusion (ICF) experiments. The first part of this paper reviews those methods used successfully to provide metal coated microspheres for ICF targets, including magnetron sputtering, electro- and electroless plating, and chemical vapor pyrolysis. The second part of this paper discusses some of the critical aspects of magnetron sputter coating of microspheres, including substrate requirements, the sticking of microspheres during coating (preventing a uniform coating), and the difficulties in growing the desired dense, smooth, uniform microstructure on continuously moving spherical substrates

Microwave measurements of water vapor partial pressure at high temperatures

International Nuclear Information System (INIS)

Latorre, V.R.

1991-01-01

One of the desired parameters in the Yucca Mountain Project is the capillary pressure of the rock comprising the repository. This parameter is related to the partial pressure of water vapor in the air when in equilibrium with the rock mass. Although there are a number of devices that will measure the relative humidity (directly related to the water vapor partial pressure), they generally will fail at temperatures on the order of 150C. Since thee author has observed borehole temperatures considerably in excess of this value in G-Tunnel at the Nevada Test Site (NTS), a different scheme is required to obtain the desired partial pressure data at higher temperatures. This chapter presents a microwave technique that has been developed to measure water vapor partial pressure in boreholes at temperatures up to 250C. The heart of the system is a microwave coaxial resonator whose resonant frequency is inversely proportional to the square root of the real part of the complex dielectric constant of the medium (air) filling the resonator. The real part of the dielectric constant of air is approximately equal to the square of the refractive index which, in turn, is proportional to the partial pressure of the water vapor in the air. Thus, a microwave resonant cavity can be used to measure changes in the relative humidity or partial pressure of water vapor in the air. Since this type of device is constructed of metal, it is able to withstand very high temperatures. The actual limitation is the temperature limit of the dielectric material in the cable connecting the resonator to its driving and monitoring equipment-an automatic network analyzer in our case. In the following sections, the theory of operation, design, construction, calibration and installation of the microwave diagnostics system is presented. The results and conclusions are also presented, along with suggestions for future work

Building blocks for ionic liquids: Vapor pressures and vaporization enthalpies of 1-(n-alkyl)-imidazoles

International Nuclear Information System (INIS)

Emel'yanenko, Vladimir N.; Portnova, Svetlana V.; Verevkin, Sergey P.; Skrzypczak, Andrzej; Schubert, Thomas

2011-01-01

Highlights: → We measured vapor pressures of the 1-(n-alkyl)-imidazoles by transpiration method. → Variations on the alkyl chain length n were C 3 , C 5 -C 7 , and C 9 -C 10 . → Enthalpies of vaporization were derived from (p, T) dependencies. → Enthalpies of vaporization at 298.15 K were linear dependent on the chain length. - Abstract: Vapor pressures of the linear 1-(n-alkyl)-imidazoles with the alkyl chain C 3 , C 5 -C 7 , and C 9 -C 10 have been measured by the transpiration method. The molar enthalpies of vaporization Δ l g H m of these compounds were derived from the temperature dependencies of vapor pressures. A linear correlation of enthalpies of vaporization Δ l g H m (298.15 K) of the 1-(n-alkyl)-imidazoles with the chain length has been found.

A Review on Metal Nanoparticles Nucleation and Growth on/in Graphene

OpenAIRE

Francesco Ruffino; Filippo Giannazzo

2017-01-01

In this review, the fundamental aspects (with particular focus to the microscopic thermodynamics and kinetics mechanisms) concerning the fabrication of graphene-metal nanoparticles composites are discussed. In particular, the attention is devoted to those fabrication methods involving vapor-phase depositions of metals on/in graphene-based materials. Graphene-metal nanoparticles composites are, nowadays, widely investigated both from a basic scientific and from several technological point of v...

Melting of contaminated metallic waste

International Nuclear Information System (INIS)

Lee, Y.-S.; Cheng, S.-Y.; Kung, H.-T.; Lin, L.-F.

2004-01-01

Approximately 100 tons of contaminated metallic wastes were produced each year due to maintenance for each TPC's nuclear power reactor and it was roughly estimated that there will be 10,000 tons of metallic scraps resulted from decommissioning of each reactor in the future. One means of handling the contaminated metal is to melt it. Melting process owns not only volume reduction which saves the high cost of final disposal but also resource conservation and recycling benefits. Melting contaminated copper and aluminum scraps in the laboratory scale have been conducted at INER. A total of 546 kg copper condenser tubes with a specific activity of about 2.7 Bq/g was melted in a vacuum induction melting facility. Three types of products, ingot, slag and dust were derived from the melting process, with average activities of 0.10 Bq/g, 2.33 Bq/g and 84.3 Bq/g respectively. After the laboratory melting stage, a pilot plant with a 500 kg induction furnace is being designed to melt the increasingly produced contaminated metallic scraps from nuclear facilities and to investigate the behavior of different radionuclides during melting. (author)

Fiber optic humidity sensor using water vapor condensation.

Science.gov (United States)

Limodehi, Hamid E; Légaré, François

2017-06-26

The rate of vapor condensation on a solid surface depends on the ambient relative humidity (RH). Also, surface plasmon resonance (SPR) on a metal layer is sensitive to the refractive index change of its adjacent dielectric. The SPR effect appears as soon as a small amount of moisture forms on the sensor, resulting in a decrease in the amount of light transmitted due to plasmonic loss. Using this concept, we developed a fiber optic humidity sensor based on SPR. It can measure the ambient RH over a dynamic range from 10% to 85% with an accuracy of 3%.

Vapor pressure and enthalpy of vaporization of oil of catnip by correlation gas chromatography

International Nuclear Information System (INIS)

Simmons, Daniel; Gobble, Chase; Chickos, James

2016-01-01

Highlights: • Vaporization enthalpies of the nepetalactones from oil of catnip have been evaluated. • Vapor pressures from T = (298.15 to 350) K have been evaluated. • Oil of catnip has a vapor pressure similar to DEET at T = 298.15 K. - Abstract: The vaporization enthalpy and vapor pressure of the two nepetalactones found in Nepeta cataria have been evaluated by correlation gas chromatography. Vaporization enthalpies at T = 298.15 K of {(68.0 ± 1.9) and (69.4 ± 1.9)} kJ ⋅ mol"−"1 have been derived for the minor diastereomer, (4aS,7S,7aS)-nepetalactone, and major one, (4aS,7S,7aR)-nepetalactone, respectively. Vapor pressures also at T = 298.15 K of p = (1.2 ± 0.04) Pa and (0.91 ± 0.03) Pa have been evaluated for the minor and the major stereoisomer. In addition to being of interest because of the remarkable effect it has on various felids, oil of catnip is also quite effective in repelling mosquitoes, comparable to diethyl-m-toluamide (DEET). The vapor pressures evaluated in this work suggest that the two stereoisomers have similar volatility to DEET at ambient temperatures.

Polonium (²¹⁰Po), uranium (²³⁴U, ²³⁸U) isotopes and trace metals in mosses from Sobieszewo Island, northern Poland.

Science.gov (United States)

Boryło, Alicja; Nowicki, Waldemar; Olszewski, Grzegorz; Skwarzec, Bogdan

2012-01-01

The activity of polonium (210)Po and uranium (234)U, (238)U radionuclides, as well as trace metals in mosses, collected from Sobieszewo Island area (northern Poland), were determined using the alpha spectrometry, AAS (atomic absorption spectrometry) and OES-ICP (atomic emission spectrometry with inductively coupled plasma). The concentrations of mercury (directly from the solid sample) were determined by the cold vapor technique of CV AAS. The obtained results revealed that the concentrations of (210)Po, (234)U, and (238)U in the two analyzed kinds of mosses: schrebers big red stem moss (Pleurozium schreberi) and broom moss (Dicranum scoparium) were similar. The higher polonium concentrations were found in broom moss (Dicranum scoparium), but uranium concentrations were relatively low for both species of analyzed mosses. Among the analyzed trace metals the highest concentration in mosses was recorded for iron, while the lowest for nickel, cadmium and mercury. The obtained studies showed that the sources of polonium and uranium isotopes, as well as trace metals in analyzed mosses are air city contaminations transported from Gdańsk and from existing in the vicinity the phosphogypsum waste heap in Wiślinka (near Gdańsk).

Thermodynamic state, specific heat, and enthalpy function of saturated UO2 vapor between 3,000 K and 5,000 K

International Nuclear Information System (INIS)

Karow, H.U.

1977-02-01

The properties have been determined by means of statistical mechanics. The discussion of the thermodynamic state includes the evaluation of the plasma state and its contribution to the caloric variables-of-state of saturated oxide fuel vapor. Because of the extremely high ion and electron density due to thermal ionization, the ionized component of the fuel vapor does no more represent a perfect kinetic plasma. At temperatures around 5,000 K, UO 2 vapor reaches the collective plasma state and becomes increasingly 'metallic'. - Moreover, the nonuniform molecular equilibrium composition of UO 2 vapor has been taken into account in calculating its caloric functions-of-state. The contribution to specific heat and enthalpy of thermally excited electronic states of the vapor molecules has been derived by means of a Rydberg orbital model of the UO 2 molecule. The resulting enthalpy functions and specific heats for saturated UO 2 vapor of equilibrium composition and that for pure UO 2 gas are compared with the enthalpy and specific heat data of gaseous UO 2 at lower temperatures known from literature. (orig./HP) [de

Oxygen partial pressure: a key to alloying and discovery in metal oxide--metal eutectic systems

International Nuclear Information System (INIS)

Holder, J.D.; Clark, G.W.; Oliver, B.F.

1978-01-01

Control of oxygen partial pressure is essential in the directional solidification of oxide--metal eutectic composites by techniques involving gas-solid and gas-liquid interactions. The existence of end components in the eutectic composite is Po 2 sensitive as are melt stoichiometry, solid phase compositions, and vapor losses due to oxidation-volatilization. Simple criteria are postulated which can aid the experimentalist in selecting the proper gas mixture for oxide--metal eutectic composite growth. The Cr 2 O 3 --Mo--Cr systems was used to verify certain aspects of the proposed criteria

Purification of uranium metal

International Nuclear Information System (INIS)

Suzuki, Kenji; Shikama, Tatsuo; Ochiai, Akira.

1993-01-01

We developed the system for purifying uranium metal and its metallic compounds and for growing highly pure uranium compounds to study their intrinsic physical properties. Uranium metal was zone refined under low contamination conditions as far as possible. The degree of the purity of uranium metal was examined by the conventional electrical resistivity measurement and by the chemical analysis using the inductive coupled plasma emission spectrometry (ICP). The results show that some metallic impurities evaporated by the r.f. heating and other usual metallic impurities moved to the end of a rod with a molten zone. Therefore, we conclude that the zone refining technique is much effective to the removal of metallic impurities and we obtained high purified uranium metal of 99.99% up with regarding to metallic impurities. The maximum residual resistivity ratio, the r.r.r., so far obtained was about 17-20. Using the purified uranium, we are attempting to grow a highly pure uranium-titanium single crystals. (author)

Reduction of eddy current losses in inductive transmission systems with ferrite sheets.

Science.gov (United States)

Maaß, Matthias; Griessner, Andreas; Steixner, Viktor; Zierhofer, Clemens

2017-01-05

Improvements in eddy current suppression are necessary to meet the demand for increasing miniaturization of inductively driven transmission systems in industrial and biomedical applications. The high magnetic permeability and the simultaneously low electrical conductivity of ferrite materials make them ideal candidates for shielding metallic surfaces. For systems like cochlear implants the transmission of data as well as energy over an inductive link is conducted within a well-defined parameter set. For these systems, the shielding can be of particular importance if the properties of the link can be preserved. In this work, we investigate the effect of single and double-layered substrates consisting of ferrite and/or copper on the inductance and coupling of planar spiral coils. The examined link systems represent realistic configurations for active implantable systems such as cochlear implants. Experimental measurements are complemented with analytical calculations and finite element simulations, which are in good agreement for all measured parameters. The results are then used to study the transfer efficiency of an inductive link in a series-parallel resonant topology as a function of substrate size, the number of coil turns and coil separation. We find that ferrite sheets can be used to shield the system from unwanted metallic surfaces and to retain the inductive link parameters of the unperturbed system, particularly its transfer efficiency. The required size of the ferrite plates is comparable to the size of the coils, which makes the setup suitable for practical implementations. Since the sizes and geometries chosen for the studied inductive links are comparable to those of cochlear implants, our conclusions apply in particular to these systems.

Vapor pressures and vaporization enthalpy of (−) α-bisabolol and (dl) menthol by correlation gas chromatography

International Nuclear Information System (INIS)

Keating, Leasa; Harris, Harold H.; Chickos, James S.

2017-01-01

Highlights: • The vaporization enthalpy and vapor pressure of (−) α-bisabolol and (dl)-menthol have been measured as a function of temperature. • Vapor pressures, vaporization enthalpies and boiling temperatures have been compared to available literature data. • Vapor pressures of (l)-menthol are compared to (dl)-menthol. - Abstract: The vapor pressures and vaporization enthalpies of (−) α-bisabolol and (dl)-menthol, two GRAS chemicals (generally recognized as safe) are evaluated by correlation gas chromatography using a series of saturated primary alcohols as standards. Vaporization enthalpies of (96.6 ± 2.4) and (74.2 ± 2.8) kJ mol −1 and vapor pressures of p/Pa = (0.020 ± 0.003) and (4.5 ± 0.44) were evaluated at T = 298.15 K for (−) α-bisabolol and (dl)-menthol, respectively, and compared to literature values. The vapor pressures of both compounds from T = (298.15 to 500) K have been derived from correlations using vapor pressures of a series of 1-alkanols and corresponding gas chromatographic retention times at 10 K intervals. The results were fit to a second order polynomial. Calculated normal boiling temperatures of T B = (574.8 and 492.7) K are calculated for (−) α-bisabolol and (dl)-menthol, respectively. A normal boiling temperature of T B = (485.2, and 489.7) K has previously been reported for (dl)-menthol. Vapor pressures for both (l)-menthol and (dl)-menthol from a previous study and (dl)-menthol from this study are compared with literature values.

Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry for the determination of Cr, Fe, Cu, Zn and Se in cereals

Science.gov (United States)

Huang, Shih-Yi; Jiang, Shiuh-Jen; Sahayam, A. C.

2014-11-01

Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry (USS-ETV-ICP-MS) has been applied to determine Cr, Fe, Cu, Zn and Se in several cereal samples. Thioacetamide was used as the modifier to enhance the ion signals. The background ions at the masses of interest were reduced in intensity significantly by using 1.0 mL min- 1 methane (CH4) as reaction cell gas in the dynamic reaction cell (DRC). Since the sensitivities of Cr, Fe, Cu, Zn and Se in different matrices were quite different, standard addition and isotope dilution methods were used for the determination of Cr, Fe, Cu, Zn and Se in these cereal samples. The method detection limits estimated from standard addition curves were about 1, 10, 4, 12 and 2 ng g- 1 for Cr, Fe, Cu, Zn and Se, respectively, in original cereal samples. This procedure has been applied to the determination of Cr, Fe, Cu, Zn and Se whose concentrations are in μg g- 1 (except Cr and Se) in standard reference materials (SRM) of National institute of standards and technology (NIST), NIST SRM 1568a Rice Flour and NIST SRM 1567a Wheat Flour and two cereal samples purchased from a local market. The analysis results of reference materials agreed with certified values at 95% confidence level according to Student's T-test. The results for the real world cereal samples were also found to be in good agreement with the pneumatic nebulization DRC ICP-MS results of the sample solutions.

Melting temperature, vapor density, and vapor pressure of molybdenum pentafluoride

Energy Technology Data Exchange (ETDEWEB)

Krause, Jr, R F; Douglas, T B [National Bureau of Standards, Washington, D.C. (USA). Inst. for Materials Research

1977-12-01

A sample of MoF/sub 5/ was prepared by reaction of MoF/sub 6/(g) and Mo(c). Melting curves of temperature against time established the melting temperature at zero impurity to be 318.85 K, the enthalpy of fusion to be 6.1 kJ mol/sup -1/ (+ - 5 per cent), and the cryoscopic impurity of the sample to be 0.15 mole per cent. In the presence of MoF/sub 6/(g) which was added to suppress disproportionation, the vapor density of MoF/sub 5/ over the liquid was measured by the transpiration method at 343, 363, and 383 K, the total MoF/sub 5/ that evaporated being determined by permanganate titration. The total vapor pressure of MoF/sub 5/ oligomers over the liquid was measured by a simple static method at 373 and 392 K, while melting temperatures were taken alternately to monitor possible contamination of the sample. Although the vapor pressures were adjusted for disproportionation, solution of MoF/sub 6/ in MoF/sub 5/ (1), and wall adsorption of MoF/sub 6/ their percentage uncertainty is probably several times that of the vapor densities. A combination of the two properties indicates the average extent of association of the saturated vapor to be near 2, which is the value for the dimer species (MoF/sub 5/)/sub 2/.

Chemical vapor deposition. Volume 2. 1975--July, 1978 (a bibliography with abstracts). Report for 1975--July 1978

International Nuclear Information System (INIS)

Smith, M.F.

1978-07-01

Research on chemical vapor deposition of carbon, carbides, ceramics, metals, and glasses are cited. Applications of this process include optical coatings, semiconducting films, laser materials, solar cells, composite fabrication, and nuclear reactor material fabrication. The physical, mechanical, and chemical properties of these coatings are covered

Modeling of velocity field for vacuum induction melting process

Institute of Scientific and Technical Information of China (English)

CHEN Bo; JIANG Zhi-guo; LIU Kui; LI Yi-yi

2005-01-01

The numerical simulation for the recirculating flow of melting of an electromagnetically stirred alloy in a cylindrical induction furnace crucible was presented. Inductive currents and electromagnetic body forces in the alloy under three different solenoid frequencies and three different melting powers were calculated, and then the forces were adopted in the fluid flow equations to simulate the flow of the alloy and the behavior of the free surface. The relationship between the height of the electromagnetic stirring meniscus, melting power, and solenoid frequency was derived based on the law of mass conservation. The results show that the inductive currents and the electromagnetic forces vary with the frequency, melting power, and the physical properties of metal. The velocity and the height of the meniscus increase with the increase of the melting power and the decrease of the solenoid frequency.

The role of surface chemical analysis in a study to select replacement processes for TCA vapor degreasing

Science.gov (United States)

Lesley, Michael W.; Davis, Lawrence E.; Moulder, John F.; Carlson, Brad A.

1995-01-01

The role of surface-sensitive chemical analysis (ESCA, AES, and SIMS) in a study to select a process to replace 1, 1, 1-trichloroethane (TCA) vapor degreasing as a steel and aluminum bonding surface preparation method is described. The effort was primarily concerned with spray-in-air cleaning processes involving aqueous alkaline and semi-aqueous cleaners and a contamination sensitive epoxy-to-metal bondline. While all five cleaners tested produced bonding strength results equal to or better than those produced by vapor degreasing, the aqueous alkaline cleaners yielded results which were superior to those produced by the semi-aqueous cleaners. The main reason for the enhanced performance appears to be a silicate layer left behind by the aqueous alkaline cleaners. The silicate layer increases the polarity of the surface and enhances epoxy-to-metal bonding. On the other hand, one of the semi-aqueous cleaners left a nonpolar carbonaceous residue which appeared to have a negative effect on epoxy-to-metal bonding. Differences in cleaning efficiency between cleaners/processes were also identified. These differences in surface chemistry, which were sufficient to affect bonding, were not detected by conventional chemical analysis techniques.

R-22 vapor explosions

International Nuclear Information System (INIS)

Anderson, R.P.; Armstrong, D.R.

1977-01-01

Previous experimental and theoretical studies of R-22 vapor explosions are reviewed. Results from two experimental investigations of vapor explosions in a medium scale R-22/water system are reported. Measurements following the drop of an unrestrained mass of R-22 into a water tank demonstrated the existence of two types of interaction behavior. Release of a constrained mass of R-22 beneath the surface of a water tank improved the visual resolution of the system thus allowing identification of two interaction mechansims: at low water temperatures, R-22/water contact would produce immediate violent boiling; at high water temperatures a vapor film formed around its R-22 as it was released, explosions were generated by a surface wave which initiated at a single location and propagated along the vapor film as a shock wave. A new vapor explosion model is proposed, it suggests explosions are the result of a sequence of three independent steps: an initial mixing phase, a trigger and growth phase, and a mature phase where a propagating shock wave accelerates the two liquids into a collapsing vapor layer causing a high velocity impact which finely fragments and intermixes the two liquids

Effect of AlN growth temperature on trap densities of in-situ metal-organic chemical vapor deposition grown AlN/AlGaN/GaN metal-insulator-semiconductor heterostructure field-effect transistors

Directory of Open Access Journals (Sweden)

Joseph J. Freedsman

2012-06-01

Full Text Available The trapping properties of in-situ metal-organic chemical vapor deposition (MOCVD grown AlN/AlGaN/GaN metal-insulator-semiconductor heterostructure field-effect transistors (MIS-HFETs with AlN layers grown at 600 and 700 °C has been quantitatively analyzed by frequency dependent parallel conductance technique. Both the devices exhibited two kinds of traps densities, due to AlN (DT-AlN and AlGaN layers (DT-AlGaN respectively. The MIS-HFET grown at 600 °C showed a minimum DT-AlN and DT-AlGaN of 1.1 x 1011 and 1.2 x 1010 cm-2eV-1 at energy levels (ET -0.47 and -0.36 eV. Further, the gate-lag measurements on these devices revealed less degradation ∼ ≤ 5% in drain current density (Ids-max. Meanwhile, MIS-HFET grown at 700 °C had more degradation in Ids-max ∼26 %, due to high DT-AlN and DT-AlGaN of 3.4 x 1012 and 5 x 1011 cm-2eV-1 positioned around similar ET. The results shows MIS-HFET grown at 600 °C had better device characteristics with trap densities one order of magnitude lower than MIS-HFET grown at 700 °C.

Induction of mouthpart deformities in chironomid larvae exposed to contaminated sediments.

NARCIS (Netherlands)

Di Veroli, A.; Goretti, E.; León Paumen, M.; Kraak, M.H.S.; Admiraal, W.

2012-01-01

The aim of the present study was to improve the cause-effect relationship between toxicant exposure and chironomid mouthpart deformities, by linking induction of mouthpart deformities to contaminated field sediments, metal mixtures and a mutagenic polycyclic aromatic compound metabolite (acridone).

Study of dryout heat fluxes in beds of inductively heated particles

International Nuclear Information System (INIS)

Dhir, V.K.; Catton, I.

1977-02-01

Experimental observations of the dryout heat fluxes for inductively heated particulate beds have been made. The data were obtained when steel and lead particles in the size distribution 295-787 microns were placed in a 4.7 cm diameter pyrex glass jar and inductively heated by passing radio frequency current through a 13.3 cm diameter multi-turn work coil encircling the jar. Distilled water, methanol and acetone were used as coolants in the experiments, while the bed height was varied from 1.0 to 8.9 cm. Different mechanisms for the dryout in deep and shallow beds have been identified. Dryout in shallow beds is believed to occur when the vapor velocity in the gas jets exceeds a certain critical velocity at which choking of the vapor occurs, leading to obstruction in the flow of the liquid toward the bed. However, deep beds dry out when gravitational force can no longer maintain a downward coolant flow rate necessary to dissipate the heat generated in the bed. The heat flux data of the investigation and that from two previous investigations made at Argonne Laboratory and at UCLA have been correlated with semi-theoretical correlations based on the proposed hydrodynamic models. The deep and shallow bed correlations are used to predict the bed height at which transition from deep to shallow bed would occur. An application of the study has been made to determine the maximum coolable depths of the core debris as a function of the particle size, bed porosity and decay heat

EVALUATION OF INDUCTANCE WITH ELECTRICAL WIRES

Directory of Open Access Journals (Sweden)

V. Kudry

2016-08-01

Full Text Available In this paper proved the possibility of developing passive electronic inductive elements based replace metal wire that is wound inductor, the wire is made of electret. The relative permeability of the electret S  10 000, several orders of magnitude greater than the permeability of conventional insulation materials, i < 10, resulting current in the wire acquires properties bias current. The essence of innovation is to replace the source of of magnetic induction flow that pervades the core of the coil. According to the theory of electrodynamics, current bias, in contrast to conduction current, generated no movement of charge along the wire, but the change of the charge in the local volume.Equivalence bias current and conduction current is manifested in the possibility of forming a magnetic field. The flow through magnetic induction coil core regardless of the current it generates, creates voltage at its ends.The paper also shows the numeric characteristics that determine the effective frequency range, specified the reason why electric a wire with і < 10 can not generate magnetic flux through the core and serve as a passive reactive component.

Design of Circular, Square, Single, and Multi-layer Induction Coils for Electromagnetic Priming Using Inductance Estimates

Science.gov (United States)

Fritzsch, Robert; Kennedy, Mark W.; Aune, Ragnhild E.

2018-02-01

Special induction coils used for electro magnetic priming of ceramic foam filters in liquid metal filtration have been designed using a combination of analytical and finite element modeling. Relatively simple empirical equations published by Wheeler in 1928 and 1982 have been used during the design process. The equations were found to accurately predict the z-component of the magnetic flux densities of both single- and multi-layer coils as verified both experimentally and by using COMSOL® 5.1 multiphysics simulations.

Local CFD kinetic model of cadmium vaporization during fluid bed incineration of municipal solid waste

Energy Technology Data Exchange (ETDEWEB)

Soria, J. [Instituto Multidisciplinario de Investigación y Desarrollo de la Patagonia Norte (IDEPA, CONICET-UNCo) y Facultad de Ingeniería, Universidad Nacional del Comahue, Buenos Aires 1400, 8300 Neuquén (Argentina); Laboratoire Procédés, Matériaux et Energie Solaire (CNRS-PROMES), 7 Rue du Four Solaire, Odeillo, 66120 Font-Romeu (France); Gauthier, D., E-mail: Daniel.Gauthier@promes.cnrs.fr [Laboratoire Procédés, Matériaux et Energie Solaire (CNRS-PROMES), 7 Rue du Four Solaire, Odeillo, 66120 Font-Romeu (France); Falcoz, Q.; Flamant, G. [Laboratoire Procédés, Matériaux et Energie Solaire (CNRS-PROMES), 7 Rue du Four Solaire, Odeillo, 66120 Font-Romeu (France); Mazza, G. [Instituto Multidisciplinario de Investigación y Desarrollo de la Patagonia Norte (IDEPA, CONICET-UNCo) y Facultad de Ingeniería, Universidad Nacional del Comahue, Buenos Aires 1400, 8300 Neuquén (Argentina)

2013-03-15

Highlights: ► A 2-D local CFD model for simulating the Cd vaporization process is presented. ► It includes a kinetic expression of Cd vaporization into the incineration process. ► Pyrolysis, volatiles’ combustion and residual carbon combustion are also taken into account. ► It fits very well the experimental results obtained on a lab-scale fluidized bed reported in literature. ► It also compares favorably with a model developed previously by the group. -- Abstract: The emissions of heavy metals during incineration of Municipal Solid Waste (MSW) are a major issue to health and the environment. It is then necessary to well quantify these emissions in order to accomplish an adequate control and prevent the heavy metals from leaving the stacks. In this study the kinetic behavior of Cadmium during Fluidized Bed Incineration (FBI) of artificial MSW pellets, for bed temperatures ranging from 923 to 1073 K, was modeled. FLUENT 12.1.4 was used as the modeling framework for the simulations and implemented together with a complete set of user-defined functions (UDFs). The CFD model combines the combustion of a single solid waste particle with heavy metal (HM) vaporization from the burning particle, and it takes also into account both pyrolysis and volatiles’ combustion. A kinetic rate law for the Cd release, derived from the CFD thermal analysis of the combusting particle, is proposed. The simulation results are compared with experimental data obtained in a lab-scale fluidized bed incinerator reported in literature, and with the predicted values from a particulate non-isothermal model, formerly developed by the authors. The comparison shows that the proposed CFD model represents very well the evolution of the HM release for the considered range of bed temperature.

Piezoelectric trace vapor calibrator

International Nuclear Information System (INIS)

Verkouteren, R. Michael; Gillen, Greg; Taylor, David W.

2006-01-01

The design and performance of a vapor generator for calibration and testing of trace chemical sensors are described. The device utilizes piezoelectric ink-jet nozzles to dispense and vaporize precisely known amounts of analyte solutions as monodisperse droplets onto a hot ceramic surface, where the generated vapors are mixed with air before exiting the device. Injected droplets are monitored by microscope with strobed illumination, and the reproducibility of droplet volumes is optimized by adjustment of piezoelectric wave form parameters. Complete vaporization of the droplets occurs only across a 10 deg. C window within the transition boiling regime of the solvent, and the minimum and maximum rates of trace analyte that may be injected and evaporated are determined by thermodynamic principles and empirical observations of droplet formation and stability. By varying solution concentrations, droplet injection rates, air flow, and the number of active nozzles, the system is designed to deliver--on demand--continuous vapor concentrations across more than six orders of magnitude (nominally 290 fg/l to 1.05 μg/l). Vapor pulses containing femtogram to microgram quantities of analyte may also be generated. Calibrated ranges of three explosive vapors at ng/l levels were generated by the device and directly measured by ion mobility spectrometry (IMS). These data demonstrate expected linear trends within the limited working range of the IMS detector and also exhibit subtle nonlinear behavior from the IMS measurement process

Determination of Metals Present in Textile Dyes Using Laser-Induced Breakdown Spectroscopy and Cross-Validation Using Inductively Coupled Plasma/Atomic Emission Spectroscopy

Directory of Open Access Journals (Sweden)

K. Rehan

2017-01-01

Full Text Available Laser-induced breakdown spectroscopy (LIBS was used for the quantitative analysis of elements present in textile dyes at ambient pressure via the fundamental mode (1064 nm of a Nd:YAG pulsed laser. Three samples were collected for this purpose. Spectra of textile dyes were acquired using an HR spectrometer (LIBS2000+, Ocean Optics, Inc. having an optical resolution of 0.06 nm in the spectral range of 200 to 720 nm. Toxic metals like Cr, Cu, Fe, Ni, and Zn along with other elements like Al, Mg, Ca, and Na were revealed to exist in the samples. The %-age concentrations of the detected elements were measured by means of standard calibration curve method, intensities of every emission from every species, and calibration-free (CF LIBS approach. Only Sample 3 was found to contain heavy metals like Cr, Cu, and Ni above the prescribed limit. The results using LIBS were found to be in good agreement when compared to outcomes of inductively coupled plasma/atomic emission spectroscopy (ICP/AES.

Line profile analyses of rhodium metal obtained by decomposition of rhodium carbonyl

International Nuclear Information System (INIS)

Chandra, D.; Mandalia, H.; Garner, M.L.; Blakely, M.K.; Lau, K.H.

1995-01-01

Metal carbonyls are important for chemical vapor deposition (CVD) of metals and alloys and formation of high surface area metallic particles which have potential applications as catalysts. Rhodium carbonyl [Rh 6 (CO) 16 ] produces high surface area metallic particles whose structure has been reported as monoclinic (I2/a) with lattice dimensions, a=17.00(±0.03)Angstrom, b=9.78(±0.02)Angstrom, c=17.53(±0.03)Angstrom and Β=121 degrees 45' ± 30' at room temperature. Generally, metal carbonyl crystals dissociate under vacuum as carbonyl gas and decompose to metallic crystals and carbon monoxide at higher temperatures. However, the behavior of rhodium carbonyl crystals is different; they decompose directly to metallic rhodium without the formation of rhodium carbonyl gas in vacuum. Several residual fine grains of rhodium metal are found after the decomposition in vacuum at relatively low temperatures. The metallic samples of rhodium were obtained from vapor pressure experiments using torsion Knudsen-effusion apparatus. X-ray diffraction analyses performed on these gains showed severely broadened Bragg reflections indicative of small particle size and/or lattice microgram. In this study, a comparison of lattice strains and domain sizes obtained by integral breadth and Fourier methods has been made. In addition a comparison of the lattice strains and domain sizes has been made between the Cauchy, Gaussian, Cauchy-Gaussian and Aqua integral breadth methods

High-resistivity unintentionally carbon-doped GaN layers with nitrogen as nucleation layer carrier gas grown by metal-organic chemical vapor deposition

Directory of Open Access Journals (Sweden)

Fu Chen

2017-12-01

Full Text Available In this letter, high-resistivity unintentionally carbon-doped GaN layers with sheet resistivity greater than 106 Ω/□ have been grown on c-plane sapphire substrates by metal-organic chemical vapor deposition (MOCVD. We have observed that the growth of GaN nucleation layers (NLs under N2 ambient leads to a large full width at half maximum (FWHM of (102 X-ray diffraction (XRD line in the rocking curve about 1576 arc sec. Unintentional carbon incorporation can be observed in the secondary ion mass spectroscopy (SIMS measurements. The results demonstrate the self-compensation mechanism is attributed to the increased density of edge-type threading dislocations and carbon impurities. The AlGaN/GaN HEMT grown on the high-resistivity GaN template has also been fabricated, exhibiting a maximum drain current of 478 mA/mm, a peak transconductance of 60.0 mS/mm, an ON/OFF ratio of 0.96×108 and a breakdown voltage of 621 V.

High-resistivity unintentionally carbon-doped GaN layers with nitrogen as nucleation layer carrier gas grown by metal-organic chemical vapor deposition

Science.gov (United States)

Chen, Fu; Sun, Shichuang; Deng, Xuguang; Fu, Kai; Yu, Guohao; Song, Liang; Hao, Ronghui; Fan, Yaming; Cai, Yong; Zhang, Baoshun

2017-12-01

In this letter, high-resistivity unintentionally carbon-doped GaN layers with sheet resistivity greater than 106 Ω/□ have been grown on c-plane sapphire substrates by metal-organic chemical vapor deposition (MOCVD). We have observed that the growth of GaN nucleation layers (NLs) under N2 ambient leads to a large full width at half maximum (FWHM) of (102) X-ray diffraction (XRD) line in the rocking curve about 1576 arc sec. Unintentional carbon incorporation can be observed in the secondary ion mass spectroscopy (SIMS) measurements. The results demonstrate the self-compensation mechanism is attributed to the increased density of edge-type threading dislocations and carbon impurities. The AlGaN/GaN HEMT grown on the high-resistivity GaN template has also been fabricated, exhibiting a maximum drain current of 478 mA/mm, a peak transconductance of 60.0 mS/mm, an ON/OFF ratio of 0.96×108 and a breakdown voltage of 621 V.

A Review on Metal Nanoparticles Nucleation and Growth on/in Graphene

Directory of Open Access Journals (Sweden)

Francesco Ruffino

2017-07-01

Full Text Available In this review, the fundamental aspects (with particular focus to the microscopic thermodynamics and kinetics mechanisms concerning the fabrication of graphene-metal nanoparticles composites are discussed. In particular, the attention is devoted to those fabrication methods involving vapor-phase depositions of metals on/in graphene-based materials. Graphene-metal nanoparticles composites are, nowadays, widely investigated both from a basic scientific and from several technological point of views. In fact, these graphene-based systems present wide-range tunable and functional electrical, optical, and mechanical properties which can be exploited for the design and production of innovative and high-efficiency devices. This research field is, so, a wide and multidisciplinary section in the nanotechnology field of study. So, this review aims to discuss, in a synthetic and systematic framework, the basic microscopic mechanisms and processes involved in metal nanoparticles formation on graphene sheets by physical vapor deposition methods and on their evolution by post-deposition processes. This is made by putting at the basis of the discussions some specific examples to draw insights on the common general physical and chemical properties and parameters involved in the synergistic interaction processes between graphene and metals.

Fuel vapor pressure (FVAPRS)

International Nuclear Information System (INIS)

Mason, R.E.

1979-04-01

A subcode (FVAPRS) is described which calculates fuel vapor pressure. This subcode was developed as part of the fuel rod behavior modeling task performed at EG and G Idaho, Inc. The fuel vapor pressure subcode (FVAPRS), is presented and a discussion of literature data, steady state and transient fuel vapor pressure equations and estimates of the standard error of estimate to be expected with the FVAPRS subcode are included

Study of near-critical states of liquid-vapor phase transition of magnesium

International Nuclear Information System (INIS)

Emelyanov, A N; Shakhray, D V; Golyshev, A A

2015-01-01

Study of thermodynamic parameters of magnesium in the near-critical point region of the liquid-vapor phase transition and in the region of metal-nonmetal transition was carried out. Measurements of the electrical resistance of magnesium after shock compression and expansion into gas (helium) environment in the process of isobaric heating was carried out. Heating of the magnesium surface by heat transfer with hot helium was performed. The registered electrical resistance of expanded magnesium was about 10 4 -10 5 times lower than the electrical resistance of the magnesium under normal condition at the density less than the density of the critical point. Thus, metal-nonmetal transition was found in magnesium. (paper)

Aluminum Nitride Micro-Channels Grown via Metal Organic Vapor Phase Epitaxy for MEMs Applications

Energy Technology Data Exchange (ETDEWEB)

Rodak, L.E.; Kuchibhatla, S.; Famouri, P.; Ting, L.; Korakakis, D.

2008-01-01

Aluminum nitride (AlN) is a promising material for a number of applications due to its temperature and chemical stability. Furthermore, AlN maintains its piezoelectric properties at higher temperatures than more commonly used materials, such as Lead Zirconate Titanate (PZT) [1, 2], making AlN attractive for high temperature micro and nanoelectromechanical (MEMs and NEMs) applications including, but not limited to, high temperature sensors and actuators, micro-channels for fuel cell applications, and micromechanical resonators. This work presents a novel AlN micro-channel fabrication technique using Metal Organic Vapor Phase Epitaxy (MOVPE). AlN easily nucleates on dielectric surfaces due to the large sticking coefficient and short diffusion length of the aluminum species resulting in a high quality polycrystalline growth on typical mask materials, such as silicon dioxide and silicon nitride [3,4]. The fabrication process introduced involves partially masking a substrate with a silicon dioxide striped pattern and then growing AlN via MOVPE simultaneously on the dielectric mask and exposed substrate. A buffered oxide etch is then used to remove the underlying silicon dioxide and leave a free standing AlN micro-channel. The width of the channel has been varied from 5 ìm to 110 ìm and the height of the air gap from 130 nm to 800 nm indicating the stability of the structure. Furthermore, this versatile process has been performed on (111) silicon, c-plane sapphire, and gallium nitride epilayers on sapphire substrates. Reflection High Energy Electron Diffraction (RHEED), Atomic Force Microscopy (AFM), and Raman measurements have been taken on channels grown on each substrate and indicate that the substrate is influencing the growth of the AlN micro-channels on the SiO2 sacrificial layer.

Highly stable [mambf6-n(o/h2o)n(ligand)2(solvent)x]n metal organic frameworks

KAUST Repository

Eddaoudi, Mohamed

2016-10-13

Provided herein are metal organic frameworks having high selectivity and stability in the present of gases and vapors including H2S, H2O, and CO2. Metal organic frameworks can comprise metal nodes and N-donor organic ligands. Further provided are methods of making metal organic frameworks.

Investigation of the fragmentation of molten metals dropped into cold water

International Nuclear Information System (INIS)

Shiralkar, G.S.

1976-11-01

The physical mechanism by which small quantities of molten metal fragment extensively when dropped into a pool of cold water was investigated. Since this subject has been the focus of considerable research in the past, some of the more prominent theories are briefly discussed. Experiments were conducted dropping small solid spheres at a high temperature instead of molten metal drops, and indicate a significant difference from the latter. Several hypotheses were proposed based on the hydrodynamics of the molten drop and tested analytically. The theory that the drop fragmentation is caused by the violent release of dissolved gas from within the drop was investigated experimentally and lead to the conclusion that tin fragmentation probably does not occur in this way. It is felt that a calculation of the dynamics of the vapor film that would be expected to surround the hot drop is needed. This calculation was not performed but several suggestions and estimates have been made. It would seem that the possibility of metal fragmentation by rapid vaporization of water entrapped within the metal drop is well worth investigating

Assessment of the microscreen phage-induction assay for screening hazardous wastes (1989)

Energy Technology Data Exchange (ETDEWEB)

Houk, V.S.; DeMarini, D.M.

1989-01-01

The Microscreen phage-induction assay, which quantitatively measures the induction of prophage Lambda in Escherichia coli WP2s(Lambda), was used to test 14 crude (unfractionated) hazardous industrial-waste samples for genotoxic activity in the presence and absence of metabolic activation. Eleven of the 14 wastes induced prophage, and induction was observed at concentrations as low as 0.4 picograms per ml. Comparisons of the mutagenic activity of these waste samples in Salmonella and their ability to induce prophage Lambda indicate that the phage-induction assay was a more-sensitive indicator of genetic damage for this group of wastes. All but one of the wastes that were mutagenic to Salmonella were detected by the phage-induction assay, and 5 wastes not mutagenic to Salmonella were genetically active in the phage assay. The enhanced ability of the phage-induction assay to detect genotoxic activity may be related to the constituents comprising these waste samples. Partial chemical characterizations of the wastes showed high concentrations of carcinogenic metals, solvents, and chlorinated compounds, most of which are detected poorly by the Salmonella assay.

Total mercury, methyl mercury, and heavy metal concentrations in Hyeongsan River and its tributaries in Pohang city, South Korea.

Science.gov (United States)

Bailon, Mark Xavier; David, Anneschel Sheehan; Park, Yeongeon; Kim, Eunhee; Hong, Yongseok

2018-04-11

Heavy metal contamination in aquatic systems is a big problem in many areas around the world. In 2016, high mercury concentrations were reported in bivalves (Corbicula leana) and sediments near the confluence of the Hyeongsan River and Chilseong Creek located in Pohang, a steel industrial city in the south-east coast of the Korean peninsula. Given that both the Chilseong and Gumu creeks run through the Pohang industrial complex and ultimately flow to the Hyeongsan River, it is imperative to determine if the industrial effluents have any impact on the mercury contamination in these two streams and the Hyeongsan River. In this work, we investigated the concentration levels of different heavy metals using cold vapor atomic fluorescence spectroscopy and inductively coupled plasma-mass spectroscopy. The metal concentration in the water samples from the Hyeongsan River, Gumu Creek, and Chilseong Creek did not exceed the limits for drinking water quality set by the US EPA and World Health Organization. However, the sediment samples were found to be heavily contaminated by Hg with levels exceeding the toxic effect threshold. Gumu Creek was found to be heavily contaminated. The concentrations of the different heavy metals increased downstream, and the samples collected from the sites in the Hyeongsan River near the Gumu Creek, an open channel for wastewater discharge of companies in the Pohang Industrial Complex, showed higher contamination levels, indicating that the effluents from the industrial complex are a possible source of contamination in the river.

Device for removing alkali metal residues from heat exchanger

International Nuclear Information System (INIS)

Matal, O.

1987-01-01

The main parts of the facility consists of a condensing vessel and a vacuum pump unit interconnected via a vacuum pipe. The heat exchanger is heated to a temperature at which the alkali metal residues evaporate. Metal vapors are collected in the condensing vessel where they condense. The removal of the alkali metal residues from the heat exchanger pipes allows thorough inspection of the pipe inside during scheduled nuclear power plant shutdowns. The facility can be used especially with reverse steam generators. (E.S.). 1 fig

Characterization of Heavy Metals in Vegetables Using Inductive ...

African Journals Online (AJOL)

Journal of Applied Sciences and Environmental Management ... Cauliflower and Onion showed high amount of Pb. On the other hand, Cucumber and Cauliflower registered maximum content of Zn. The heavy metal concentration in vegetables was within the prescribed safety limits except Fe owing to iron-rich soil of the ...

Numerical simulation on the explosive boiling phenomena on the surface of molten metal

International Nuclear Information System (INIS)

Chen Deqi; Peng Cheng; Wang Qinghua; Pan Liangming

2014-01-01

In this paper, numerical simulation was carried out to investigate the explosive boiling phenomenon on high temperature surface also the influence of vapor growth rate during explosive boiling, vapor condensation in sub-cooled water and the subsequent effect on flowing and heat transfer. The simulation result indicates that the steam on the molten metal surface grows with very high speed, and it pushes away the sub-cooled water around and causes severe flowing. The steam clusters which block the sub-cooled water to rewet the molten metal surface are appearing at the same time. During the growth, lifting off as well as condensation of the steam clusters, the sub-cooled water around is strongly disturbed, and obvious vortexes appear. Conversely, the vortex will influence the steam cluster detachment and cub-cooled water rewetting the metal surface. This simulation visually displays the complex explosive boiling phenomena on the molten metal surface with high temperature. (authors)

Fundamental study on metal plating removal using pulsed power technology

International Nuclear Information System (INIS)

Imasaka, Kiminobu; Gnapowski, Sebastian; Akiyama, Hidenori

2013-01-01

A novel method for the metal removal from metal-plated substrate using pulsed power technology is proposed. A metal-plated substrate with three metal-layers structure (Cu, Ni and Au) is used as the sample substrate. Repetitive pulsed arc discharge plasma is generated between a rod electrode and the surface of substrate. Effect of the type of electrode system on metal plating removal was investigated. The removal region is produced by the moving phenomena of the pulsed arc discharge. A part of Au layer, which is the tompost metal surface of the substrate is vaporized and removed by the repetitive pulsed arc discharges. The proposed method can be used for recycle of metal-plated substrate. (author)

Phenomenological modeling of the thermal dynamics of a rotating cylinder heated by electromagnetic induction; Modelisation phenomenologique de la dynamique thermique d'un cylindre rotatoire chauffe par induction electromagnetique

Energy Technology Data Exchange (ETDEWEB)

Perez, S. [Universidad de Carabobo, Facultad de Ingenieria, Valencia (Venezuela); Therien, N.; Broadbent, A.D. [Sherbrooke Univ., Faculte de Genie, Quebec (Canada)

2001-07-01

This work concerns the development of a phenomenological model describing the temperature dynamics of a metal cylinder heated by electric induction. The model used takes into consideration in an explicit way the different mechanisms of energy transfer from the cylinder towards the environment, in particular the convection and radiant heat transfers. The conduction process, which takes place inside the cylinder as a response to the temperature gradient at the periphery of the cylinder, has been characterized too. The process of energy induction inside the cylinder has been characterized in a precise way. The experiments show that the induction is localized in the part of the cylinder facing the inductors and that the induction presents a distributed feature in the induction section. The model proposed is based on the concept of substantial derivative. It calculates the response of the process with respect to these disturbances and with respect to the rotation speed of the cylinder and to the electric power supplied to the system. (J.S.)

Nucleation and growth of vapor bubbles in the liquid bulk and at a solid surface

International Nuclear Information System (INIS)

Yagov, V.V.

1977-01-01

The main achievements in the study of the vapor phase origin in liquid and the subsequent growth of the vapor bubbles are presented briefly, and a number of issues on which there is no single opinion as yet are also outlined. The theory of homogeneous nucleation and a great number of experiments make it possible not only to explain qualitatively the causes of spontaneous formation of vapor nucleation centers in the metastable liquid but provides a simple computational relation for the estimating the intensity of this process. None of the existing hypotheses, however, can give a complete answer to the question of the mechanism of the vapor phase nucleation on a solid surface under ''pure conditions'', although this is a more pressing problem. At the same time, the role of cavities of reservoir type (with a narrow orifice) on the surface under heating as reliable stabilizers of the vapor formation (especially in liquid metals) is clarified from the practical point of view. Thus, the identification of technology for production of such cavities would make it possible to increase substantially the efficiency of heat transferring surfaces. Any computational relations for the growth of bubbles on the heating surface also are (and, according to the author, necessarily will be) approximate ones, although considerable success has been achieved in this field

Induction detection of concealed bulk banknotes

International Nuclear Information System (INIS)

Fuller, Christopher; Chen, Antao

2011-01-01

Bulk cash smuggling is a serious issue that has grown in volume in recent years. By building on the magnetic characteristics of paper currency, induction sensing is found to be capable of quickly detecting large masses of banknotes. The results show that this method is effective in detecting bulk cash through concealing materials such as plastics, cardboards, fabrics and aluminum foil. The significant difference in the observed phase between the received signals caused by conducting materials and ferrite compounds, found in banknotes, provides a good indication that this process can overcome the interference by metal objects in a real sensing application. This identification strategy has the potential to not only detect the presence of banknotes, but also the number, while still eliminating false positives caused by metal objects

Vapor generation methods for explosives detection research

Energy Technology Data Exchange (ETDEWEB)

Grate, Jay W.; Ewing, Robert G.; Atkinson, David A.

2012-12-01

The generation of calibrated vapor samples of explosives compounds remains a challenge due to the low vapor pressures of the explosives, adsorption of explosives on container and tubing walls, and the requirement to manage (typically) multiple temperature zones as the vapor is generated, diluted, and delivered. Methods that have been described to generate vapors can be classified as continuous or pulsed flow vapor generators. Vapor sources for continuous flow generators are typically explosives compounds supported on a solid support, or compounds contained in a permeation or diffusion device. Sources are held at elevated isothermal temperatures. Similar sources can be used for pulsed vapor generators; however, pulsed systems may also use injection of solutions onto heated surfaces with generation of both solvent and explosives vapors, transient peaks from a gas chromatograph, or vapors generated by s programmed thermal desorption. This article reviews vapor generator approaches with emphasis on the method of generating the vapors and on practical aspects of vapor dilution and handling. In addition, a gas chromatographic system with two ovens that is configurable with up to four heating ropes is proposed that could serve as a single integrated platform for explosives vapor generation and device testing. Issues related to standards, calibration, and safety are also discussed.

Highly stable [mambf6-n(o/h2o)n(ligand)2(solvent)x]n metal organic frameworks

KAUST Repository

Eddaoudi, Mohamed; Adil, Karim; Belmabkhout, Youssef; Shekhah, Osama; Bhatt, Prashant M.; Cadiau, Amandine

2016-01-01

Provided herein are metal organic frameworks having high selectivity and stability in the present of gases and vapors including H2S, H2O, and CO2. Metal organic frameworks can comprise metal nodes and N-donor organic ligands. Further provided

Low-Temperature Preparation of (111)-oriented Pb(Zr,Ti)O3 Films Using Lattice-Matched (111)SrRuO3/Pt Bottom Electrode by Metal-Organic Chemical Vapor Deposition

Science.gov (United States)

Kuwabara, Hiroki; Sumi, Akihiro; Okamoto, Shoji; Hoko, Hiromasa; Cross, Jeffrey S.; Funakubo, Hiroshi

2009-04-01

Pb(Zr0.35Ti0.65)O3 (PZT) films 170 nm thick were prepared at 415 °C by pulsed metal-organic chemical vapor deposition. The (111)-oriented PZT films with local epitaxial growth were obtained on (111)SrRuO3/(111)Pt/TiO2/SiO2/Si substrates and their ferroelectricities were ascertained. Ferroelectricity was improved by postannealing under O2 gas flow up to 550 °C. Larger remanent polarization and better fatigue endurance were obtained using a SrRuO3 top electrode compared to a Pt top electrode for PZT films after annealing at 500 °C.

Uranium metal production by molten salt electrolysis

International Nuclear Information System (INIS)

Takasawa, Yutaka

1999-01-01

Atomic vapor laser isotope separation (AVLIS) is a promising uranium enrichment technology in the next generation. Electrolytic reduction of uranium oxides into uranium metal is proposed for the preparation of uranium metal as a feed material for AVLIS plant. Considering economical performance, continuos process concept and minimizing the amount of radioactive waste, an electrolytic process for producing uranium metal directly from uranium oxides will offer potential advantages over the existing commercial process. Studies of uranium metal by electrolysis in fluoride salts (BaF 2 -LiF-UF 4 (74-11-15 w/o) at 1150-1200degC, using both a laboratory scale apparatus and an engineering scale one, and continuous casting of uranium metal were carried out in order to decide the optimum operating conditions and the design of the industrial electrolytic cells. (author)

Investigation into the behavior of metal-argon polyatomic ions (MAr+) in the extraction region of inductively coupled plasma-mass spectrometry

International Nuclear Information System (INIS)

Ebert, Chris H.; Witte, Travis M.; Houk, R.S.

2012-01-01

The abundances of metal-argon polyatomic ions (MAr + ) are determined in inductively coupled plasma-mass spectrometry (ICP-MS). The ratios of MAr + abundance to that for M + ions are measured experimentally. These ratios are compared to expected values, calculated for typical plasma conditions using spectroscopic data. For all metals studied (Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn), the measured ratios are significantly lower than the calculated ratios. Increasing the plasma potential (and thereby increasing the ion kinetic energy) by means of a homemade guard electrode with a wide gap further reduces the MAr + /M + ratio. Implementing a skimmer cone designed for high transmission of light ions increases the MAr + abundance. Considering this evidence, the scarcity of MAr + ions is attributed to collision induced dissociation (CID), likely due to a shock wave at the tip of or in the throat of the skimmer cone. - Highlights: ► MAr + ions are less abundant in the mass spectrum than expected from the ICP. ► Increasing the plasma potential reduces their abundance further. ► The extraction lens voltage does not greatly affect the MAr + abundances. ► The weakly-bound MAr + ions are probably dissociated by collisions during extraction.

Application of induction heating in food processing and cooking: A Review

Science.gov (United States)

Induction heating is an electromagnetic heating technology that has several advantages such as high safety, scalability, and high energy efficiency. It has been applied for a long time in metal processing, medical applications, and cooking. However, the application of this technology in the food pro...

40 CFR Appendix C to Part 438 - Metal-Bearing Operations Definitions

Science.gov (United States)

2010-07-01

... is rotated in a drum containing a water-based solution, glass beads, and metal powder. In vapor... interference shielding; thermal barriers for rocket engines; nuclear moderators; films for hot isostatic...

Chemical metallization of KMPR photoresist polymer in aqueous solutions

Energy Technology Data Exchange (ETDEWEB)

Zeb, Gul [MiQro Innovation Collaborative Centre (C2MI), 45, boul. de l' Aéroport, Bromont, QC, J2L 1S8 (Canada); Mining & Materials Engineering, McGill University, 3610,University Street, Montreal, QC, H3A 0C5 (Canada); Duong, Xuan Truong [Department of Mechanical Engineering, Ecole polytechnique de Montréal, Montréal, QC, H3C 3T5 (Canada); Thai Nguyen University of Technology, 3-2 Street, Thai Nguyen City (Viet Nam); Vu, Ngoc Pi; Phan, Quang The; Nguyen, Duc Tuong; Ly, Viet Anh [Thai Nguyen University of Technology, 3-2 Street, Thai Nguyen City (Viet Nam); Salimy, Siamak [ePeer Review LLC, 145 Pine Haven Shores Rd, Suite 1000-X, Shelburne, VT 05482 (United States); Le, Xuan Tuan, E-mail: xuantuan.le@teledyne.com [MiQro Innovation Collaborative Centre (C2MI), 45, boul. de l' Aéroport, Bromont, QC, J2L 1S8 (Canada); Thai Nguyen University of Technology, 3-2 Street, Thai Nguyen City (Viet Nam)

2017-06-15

Highlights: • Electroless deposition of Ni-B film on KMPR photoresist polymer insulator with excellent adhesion has been achieved. • This metallization has been carried out in aqueous solutions at low temperature. • Polyamine palladium complexes grafts serve as seeds for the electroless plating on KMPR. • This electroless metallization process is simple, industrially feasible, chromium-free and environment-friendly. - Abstract: While conventional methods for preparing thin films of metals and metallic alloys on insulating substrates in the field of microelectromechanical systems (MEMS) include vapor deposition techniques, we demonstrate here that electroless deposition can be considered as an alternate efficient approach to metallize the surface of insulating substrates, such as KMPR epoxy photoresist polymer. In comparison with the physical and chemical vapor deposition methods, which are well-established for metallization of photoresist polymers, our electroless nickel plating requires only immersing the substrates into aqueous solutions in open air at low temperatures. Thin films of nickel alloy have been deposited electrolessly on KMPR surface, through a cost-effective and environmental chromium-free process, mediated through direct grafting of amine palladium complexes in aqueous medium. This covalent organic coating provides excellent adhesion between KMPR and the nickel film and allows better control of the palladium catalyst content. Covalent grafting and characterization of the deposited nickel film have been carried out by means of Fourier-transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy techniques.

Quantitative analysis of some important metals and metalloids in tobacco products by inductively coupled plasma-mass spectrometry (ICP-MS)

Science.gov (United States)

2012-01-01

Background Large scale usage of tobacco causes a lot of health troubles in human. Various formulations of tobacco are extensively used by the people particularly in developing world. Besides several toxic tobacco constituents some metals and metalloids are also believed to pose health risks. This paper describes inductively coupled plasma-mass spectrometric (ICP-MS) quantification of some important metals and metalloids in various brands of smoked, sniffed, dipped and chewed tobacco products. Results A microwave-assisted digestion method was used for sample preparation. The method was validated by analyzing a certified reference material. Percentage relative standard deviation (% R.S.D.) between recovered and certified values was  r > 0.999. Improved limits of detection (LODs) were in range of ng/L for all elements. Fe, Al and Mn were found to be in the highest concentration in all types of tobacco products, while Zn, Cu, Ni and Cr were below the average concentration of 40 μg/g, and Pb, Co, As, Se and Cd were below 5 μg/g. All elements, apart from Pb, were high in concentration in dipping tobacco in comparison to other tobacco products. Generally, the order of all elemental concentration can be expressed in different tobacco products as chewing metalloids in a wide spectrum of tobacco formulations. The outcome of this study would be beneficial for health authorities and individuals. PMID:22709464

The vaporization enthalpy and vapor pressure of S (+)-methamphetamine at T = 298.15 K by correlation gas chromatography

International Nuclear Information System (INIS)

Thornton, Melissa; Gobble, Chase; Chickos, James

2014-01-01

Highlights: • The vaporization enthalpy of (d)-methamphetamine was measured. • The vapor pressure of (d)-methamphetamine as a function of temperature was evaluated. • The vapor pressure of 4-benzylpiperidine as a function of temperature was evaluated. - Abstract: The vaporization enthalpy and vapor pressure of S (+)-methamphetamine is evaluated by correlation-gas chromatography. A vaporization enthalpy of (58.7 ± 4.3) kJ · mol −1 and a vapor pressure, p = (38 ± 9) Pa has been obtained using a variety of secondary aliphatic amines as standards. In addition, equations describing the vapor pressure temperature dependence are provided for standards and S (+)-methamphetamine covering the temperature range from T = 298.15 K to the boiling temperature. Boiling temperatures are reproduced within an interval of 8 K or less

Diatomaceous earth and activated bauxite used as granular sorbents for the removal of sodium chloride vapor from hot flue gas

Energy Technology Data Exchange (ETDEWEB)

Lee, S.H.D.; Swift, W.M.; Johnson, I.

1980-01-01

Diatomaceous earth and activated bauxite were tested as granular sorbents for use as filter media in granular-bed filters for the removal of gaseous alkali metal compounds from the hot (800/sup 0/C) flue gas of PFBC. Tests were performed at atmospheric pressure, using NaCl vapor transported in relatively dry simulated flue gas of PFBC. Either a fixed-bed combustor or a high-temperature sorption test rig was used. The effects of sorbent bed temperature, superficial gas velocity, gas hourly space velocity, and NaCl-vapor concentration in flue gas on the sorption behavior of these two sorbents and their ultimate sorption capacities were determined. Both diatomaceous earth and activated bauxite were found to be very effective in removing NaCl vapor from flue gas. Preliminary cost evaluations showed that they are economically attractive as granular sorbents for cleaning alkali vapor from simulated flue gas.

Observation and particle simulation of vaporized W, Mo, and Be in PISCES-B plasma for vapor-shielding studies

Directory of Open Access Journals (Sweden)

K. Ibano

2017-08-01

Full Text Available Interactions of Tungsten (W, Molybdenum (Mo, and Beryllium (Be vapors with a steady-state plasma were studied by the PISCES-B liner plasma experiments as well as Particle-In-Cell (PIC simulations for the understanding of vapor-shielding phenomena. Effective cooling of the plasma by laser-generated Be vapor was observed in PISCES-B. On the other hand, no apparent cooling was observed for W and Mo vapors. The PIC simulation explains these experimental observations of the difference between low-Z and high-Z vapors. Decrease of electron temperature due to the vapor ejection was observed in case of a simulation of the Be vapor. As for the W vapor, it was found that the plasma cooling is localized only near the wall at a higher electron density plasma (∼1019m−3. On the other hand, the appreciable plasma cooling can be observed in a lower density plasma (∼1018m−3 for the W vapor.

Determination of arsenic, lead, selenium and tin in sediments by slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry using Ru as permanent modifier and NaCl as a carrier

International Nuclear Information System (INIS)

Dias, Lucia Felicidade; Saint'Pierre, Tatiana D.; Maia, Sandra M.; Mesquita da Silva, Marcia A.; Frescura, Vera L.A.; Welz, Bernhard; Curtius, Adilson J.

2002-01-01

A procedure for the determination of As, Pb, Se and Sn in sediment slurries by electrothermal vaporization inductively coupled plasma mass spectrometry is proposed. The slurry, 1 mg ml -1 , is prepared by mixing the sample ground to a particle size ≤50 μm with 5% v/v nitric and 1% v/v hydrofluoric acids in an ultrasonic bath. The slurry was homogenized with a constant flow of argon in the autosampler cup, just before transferring an aliquot to the graphite furnace. The tube was treated with Ru as a permanent modifier, and an optimized mass of 1 μg of NaCl was added as a physical carrier. The pyrolysis temperature was optimized through pyrolysis curves, and a compromised temperature of 800 deg. C was used; the vaporization temperature was 2300 deg. C. The effect of different acid concentrations in the slurry on the analyte signal intensities was also evaluated. The accuracy of the method was assured by the analysis of certified reference sediments MESS-2, PACS-2 and HISS-1 from the National Research Council Canada, SRM 2704 and SRM 1646a from the National Institute of Standards and Technology and RS-4 from a round robin test, using external calibration with aqueous standards prepared in the same medium as the slurries. The obtained concentrations were in agreement with the certified values according to the Student's t-test for a confidence level of 95%. The detection limits in the samples were: 0.17 μg g -1 for As; 0.3 μg g -1 for Pb; 0.05 μg g -1 for Se and 0.28 μg g -1 for Sn. The precision found for the different sediment samples, expressed as R.S.D. was 1-8% for As, 2-9% for Pb, 6-12% for Se and 3-8% for Sn (n=5)

Passive vapor extraction feasibility study

International Nuclear Information System (INIS)

Rohay, V.J.

1994-01-01

Demonstration of a passive vapor extraction remediation system is planned for sites in the 200 West Area used in the past for the disposal of waste liquids containing carbon tetrachloride. The passive vapor extraction units will consist of a 4-in.-diameter pipe, a check valve, a canister filled with granular activated carbon, and a wind turbine. The check valve will prevent inflow of air that otherwise would dilute the soil gas and make its subsequent extraction less efficient. The granular activated carbon is used to adsorb the carbon tetrachloride from the air. The wind turbine enhances extraction rates on windy days. Passive vapor extraction units will be designed and operated to meet all applicable or relevant and appropriate requirements. Based on a cost analysis, passive vapor extraction was found to be a cost-effective method for remediation of soils containing lower concentrations of volatile contaminants. Passive vapor extraction used on wells that average 10-stdft 3 /min air flow rates was found to be more cost effective than active vapor extraction for concentrations below 500 parts per million by volume (ppm) of carbon tetrachloride. For wells that average 5-stdft 3 /min air flow rates, passive vapor extraction is more cost effective below 100 ppm

Electrical properties of metal/Al2O3/In0.53Ga0.47As capacitors grown on InP

Science.gov (United States)

Ferrandis, Philippe; Billaud, Mathilde; Duvernay, Julien; Martin, Mickael; Arnoult, Alexandre; Grampeix, Helen; Cassé, Mikael; Boutry, Hervé; Baron, Thierry; Vinet, Maud; Reimbold, Gilles

2018-04-01

To overcome the Fermi-level pinning in III-V metal-oxide-semiconductor capacitors, attention is usually focused on the choice of dielectric and surface chemical treatments prior to oxide deposition. In this work, we examined the influence of the III-V material surface cleaning and the semiconductor growth technique on the electrical properties of metal/Al2O3/In0.53Ga0.47As capacitors grown on InP(100) substrates. By means of the capacitance-voltage measurements, we demonstrated that samples do not have the same total oxide charge density depending on the cleaning solution used [(NH4)2S or NH4OH] prior to oxide deposition. The determination of the interface trap density revealed that a Fermi-level pinning occurs for samples grown by metalorganic chemical vapor deposition but not for similar samples grown by molecular beam epitaxy. Deep level transient spectroscopy analysis explained the Fermi-level pinning by an additional signal for samples grown by metalorganic chemical vapor deposition, attributed to the tunneling effect of carriers trapped in oxide toward interface states. This work emphasizes that the choice of appropriate oxide and cleaning treatment is not enough to prevent a Fermi-level pinning in III-V metal-oxide-semiconductor capacitors. The semiconductor growth technique needs to be taken into account because it impacts the trapping properties of the oxide.

Electrical resistivity of ceramic-metal composite materials in the percolation region: application in crucibles for induction furnaces; Resistividade eletrica de materiais compositos do tipo ceramica-metal na regiao de percolacao: aplicacao em cadinhos para fornos de inducao

Energy Technology Data Exchange (ETDEWEB)

Sene, Frank Ferrer

1997-07-01

Ceramic composite materials were produced by mixing powders of Partially Stabilized (PSZ) with titanium, niobium or nickel, and cristobalite with titanium. Pellets were produced by uniaxially pressing the material followed by cold isostatic pressing and finally sintering at 1600 deg C for 1,5 hours in argon. The metal content was varied in the range of 0-40 volume percent (v/o). Electrical resistivity measurements were performed in the temperature range of 25 - 700 deg C. Samples containing metallic inclusions above 25 v/o show the predominance of electronic type conducting. For samples with metallic inclusion below 25 v/o, a typically ionic conduction behavior has been observed. PSZ-Ti and PSZ-Ni samples containing 25 v/o of metallic inclusions show an insulator - conductor transition in a given temperature range. Cristobalite samples containing 30 v/o of titanium show a conductor - insulator transition also in a specific temperature range. Tests performed in an induction furnace showed that samples containing metallic inclusions above 25 v/o had self-heated when exposed to electro magnetic fields in the range of radio frequency (r.f.) Crucibles of PSZ-Ti were made by slip casting followed by sintering at 1600 deg C for 1.5 hours in argon. These crucibles were exposed to electromagnetic fields in the r.f. range and the maximum temperature reached was 1350 deg C. Microstructure characterization was performed on those materials by X-ray diffraction, EDS, optical and scanning electron microscopy. (author)

A heated vapor cell unit for dichroic atomic vapor laser lock in atomic rubidium.

Science.gov (United States)

McCarron, Daniel J; Hughes, Ifan G; Tierney, Patrick; Cornish, Simon L

2007-09-01

The design and performance of a compact heated vapor cell unit for realizing a dichroic atomic vapor laser lock (DAVLL) for the D(2) transitions in atomic rubidium is described. A 5 cm long vapor cell is placed in a double-solenoid arrangement to produce the required magnetic field; the heat from the solenoid is used to increase the vapor pressure and correspondingly the DAVLL signal. We have characterized experimentally the dependence of important features of the DAVLL signal on magnetic field and cell temperature. For the weaker transitions both the amplitude and gradient of the signal are increased by an order of magnitude.

A heated vapor cell unit for dichroic atomic vapor laser lock in atomic rubidium

International Nuclear Information System (INIS)

McCarron, Daniel J.; Hughes, Ifan G.; Tierney, Patrick; Cornish, Simon L.

2007-01-01

The design and performance of a compact heated vapor cell unit for realizing a dichroic atomic vapor laser lock (DAVLL) for the D 2 transitions in atomic rubidium is described. A 5 cm long vapor cell is placed in a double-solenoid arrangement to produce the required magnetic field; the heat from the solenoid is used to increase the vapor pressure and correspondingly the DAVLL signal. We have characterized experimentally the dependence of important features of the DAVLL signal on magnetic field and cell temperature. For the weaker transitions both the amplitude and gradient of the signal are increased by an order of magnitude

Detection of organic vapors on sputtered and annealed thin Au films

Science.gov (United States)

Kvitek, O.; Kopacek, V.; Reznickova, A.; Svorcik, V.

2018-03-01

Unique optical properties of metal nanostructures enable construction of new types of chemical sensors. Nanostructures composed of Au on glass substrate were prepared by annealing of 2-20 nm thick sputtered Au films at 300 °C for 1 h. The annealing leads to transformation of the as sputtered continuous Au layers to a nanoisland structure. The forming nanostructure shows a strong, well defined surface plasmon resonance absorption band in UV-Vis spectrum, which is useful for construction of a chemical sensor. The samples were used to detect vapors of acetone and water in an experimental testing apparatus. The achieved signal-to-noise ratio was 583 and 386 for acetone and water vapors, respectively on the nanostructure prepared from 4 nm thick Au layer. The nanostructured sensitive layers, however, showed poor signal stability; therefore a polymer overlayer was introduced to protect it. The employed polystyrene film prepared by spin-coating improved sensitivity and selectivity of the sensor, while the dynamic properties of the sensing influenced only slightly.

Induction of Cellular Metallothionein in Irradiated Rats Supplemented with Egyptian Propolis Extract

International Nuclear Information System (INIS)

Nada, A.SH.; Azab, KH.SH.

2005-01-01

Proplis, a resinous yellow to dark substance collected by worker honeybees has been extensively used in folk medicine for management of a wide spectrum of disorders. The current study was conducted to evaluate the role of Egyptian propolis extract in modification of metallothionen (MT) induction in rats exposed to whole body fractionated gamma irradiation (delivered as 1.5 Gy every day up to 7.5 Gy total dose) and the relevance of certain metals (Cu, Zn, Mg, Mn and Fe) for metallothionein induction. In addition, lipid peroxides (thiobarbituric acid reactive substance; TEARS) and reduced glutathione (GSH) concentrations were observed in different subjected tissues. Metal content of crude propolis and certain related natural forms (bee pollen and honey) were also identified. Propolis extract was supplemented daily to rats (10 ml/kg body wt/day) by stomach tube, 15 days before and during exposure to gamma radiation. Experimental investigations were carried out on the 1st and 10th days after the last irradiation fraction in liver, kidney, brain, heart, lung and spleen tissues. The results obtained reveal that the administration of propolis extract increased significantly the metallothionein (MT) concentration in all examined tissues as compared with control rats. Records on all subjected tissues imparted that propolis extract supplementation has significantly minimized the radiation-induced increases in the amount of TBARS, maintained GSH con centration within normal levels except for lung and spleen and increased MT levels comparing to irradiated rats. Furthermore, significant amelioration in the levels of trace metals was observed such as zinc and copper in liver, kidney and brain. It could be postulated that the prolonged administration of Egyptian propolis extract attenuates the lipid peroxidation process in different rat's tissues and that might attributed to its antioxidant potency partially expressed through MT induction, maintenance of GSH levels and the

Effects of Induction Heat Bending Process on Microstructure and Corrosion Properties of ASME SA312 Gr.TP304 Stainless Steel Pipes

International Nuclear Information System (INIS)

Kim, Nam In; Kim, Young Sik; Kim, Kyung Soo; Chang, Hyun Young; Park, Heung Bae; Sung, Gi Ho; Sung, Gi Ho

2015-01-01

The usage of bending products recently have increased since many industries such as automobile, aerospace, shipbuilding, and chemical plants need the application of pipings. Bending process is one of the inevitable steps to fabricate the facilities. Induction heat bending is composed of compressive bending process by local heating and cooling. This work focused on the effect of induction heat bending process on the properties of ASME SA312 Gr. TP304 stainless steel pipes. Tests were performed for base metal and bended area including extrados, intrados, crown up, and down parts. Microstructure was analyzed using an optical microscope and SEM. In order to determine intergranular corrosion resistance, Double Loop Electrochemical Potentiokinetic Reactivation (DL-EPR) test and ASTM A262 practice A and C tests were done. Every specimen revealed non-metallic inclusion free under the criteria of 1.5i of the standard and the induction heat bending process did not affect the non-metallic inclusion in the alloys. Also, all the bended specimens had finer grain size than ASTM grain size number 5 corresponding to the grain sizes of the base metal and thus the grain size of the pipe bended by induction heat bending process is acceptable. Hardness of transition start, bend, and transition end areas of ASME SA312 TP304 stainless steel was a little higher than that of base metal. Intergranular corrosion behavior was determined by ASTM A262 practice A and C and DL-EPR test, and respectively step structure, corrosion rate under 0.3 mm/y, and Degree of Sensitization (DOS) of 0.001 - 0.075 % were obtained. That is, the induction heat bending process didn't affect the intergranular corrosion behavior of ASME SA312 TP304 stainless steel

High temperature vapors science and technology

CERN Document Server

Hastie, John

2012-01-01

High Temperature Vapors: Science and Technology focuses on the relationship of the basic science of high-temperature vapors to some areas of discernible practical importance in modern science and technology. The major high-temperature problem areas selected for discussion include chemical vapor transport and deposition; the vapor phase aspects of corrosion, combustion, and energy systems; and extraterrestrial high-temperature species. This book is comprised of seven chapters and begins with an introduction to the nature of the high-temperature vapor state, the scope and literature of high-temp

Copper-vapor-catalyzed chemical vapor deposition of graphene on dielectric substrates

Science.gov (United States)

Yang, Chao; Wu, Tianru; Wang, Haomin; Zhang, Xuefu; Shi, Zhiyuan; Xie, Xiaoming

2017-07-01

Direct synthesis of high-quality graphene on dielectric substrates is important for its application in electronics. In this work, we report the process of copper-vapor-catalyzed chemical vapor deposition of high-quality and large graphene domains on various dielectric substrates. The copper vapor plays a vital role on the growth of transfer-free graphene. Both single-crystal domains that are much larger than previous reports and high-coverage graphene films can be obtained by adjusting the growth duration. The quality of the obtained graphene was verified to be comparable with that of graphene grown on Cu foil. The progress reported in this work will aid the development of the application of transfer-free graphene in the future.

Estimated vapor pressure for WTP process streams

Energy Technology Data Exchange (ETDEWEB)

Pike, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Poirier, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2015-01-01

Design assumptions during the vacuum refill phase of the Pulsed Jet Mixers (PJMs) in the Hanford Waste Treatment and Immobilization Plant (WTP) equate the vapor pressure of all process streams to that of water when calculating the temperature at which the vacuum refill is reduced or eliminated. WTP design authority asked the authors to assess this assumption by performing calculations on proposed feed slurries to calculate the vapor pressure as a function of temperature. The vapor pressure was estimated for each WTP waste group. The vapor pressure suppression caused by dissolved solids is much greater than the increase caused by organic components such that the vapor pressure for all of the waste group compositions is less than that of pure water. The vapor pressure for each group at 145°F ranges from 81% to 98% of the vapor pressure of water. If desired, the PJM could be operated at higher temperatures for waste groups with high dissolved solids that suppress vapor pressure. The SO4 group with the highest vapor pressure suppression could be operated up to 153°F before reaching the same vapor pressure of water at 145°F. However, most groups would reach equivalent vapor pressure at 147 to 148°F. If any of these waste streams are diluted, the vapor pressure can exceed the vapor pressure of water at mass dilution ratios greater than 10, but the overall effect is less than 0.5%.

Examination of Organic Vapor Adsorption onto Alkali Metal and Halide Atomic Ions by using Ion Mobility Mass Spectrometry.

Science.gov (United States)

Maiβer, Anne; Hogan, Christopher J

2017-11-03

We utilize ion mobility mass spectrometry with an atmospheric pressure differential mobility analyzer coupled to a time-of-flight mass spectrometer (DMA-MS) to examine the formation of ion-vapor molecule complexes with seed ions of K + , Rb + , Cs + , Br - , and I - exposed to n-butanol and n-nonane vapor under subsaturated conditions. Ion-vapor molecule complex formation is indicated by a shift in the apparent mobility of each ion. Measurement results are compared to predicted mobility shifts based upon the Kelvin-Thomson equation, which is commonly used in predicting rates of ion-induced nucleation. We find that n-butanol at saturation ratios as low as 0.03 readily binds to all seed ions, leading to mobility shifts in excess of 35 %. Conversely, the binding of n-nonane is not detectable for any ion for saturation ratios in the 0-0.27 range. An inverse correlation between the ionic radius of the initial seed and the extent of n-butanol uptake is observed, such that at elevated n-butanol concentrations, the smallest ion (K + ) has the smallest apparent mobility and the largest (I - ) has the largest apparent mobility. Though the differences in behavior of the two vapor molecules types examined and the observed effect of ionic seed radius are not accounted for by the Kelvin-Thomson equation, its predictions are in good agreement with measured mobility shifts for Rb + , Cs + , and Br - in the presence of n-butanol (typically within 10 % of measurements). © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

A numerical investigation of vapor intrusion--the dynamic response of contaminant vapors to rainfall events.

Science.gov (United States)

Shen, Rui; Pennell, Kelly G; Suuberg, Eric M

2012-10-15

The U.S. government and various agencies have published guidelines for field investigation of vapor intrusion, most of which suggest soil gas sampling as an integral part of the investigation. Contaminant soil gas data are often relatively more stable than indoor air vapor concentration measurements, but meteorological conditions might influence soil gas values. Although a few field and numerical studies have considered some temporal effects on soil gas vapor transport, a full explanation of the contaminant vapor concentration response to rainfall events is not available. This manuscript seeks to demonstrate the effects on soil vapor transport during and after different rainfall events, by applying a coupled numerical model of fluid flow and vapor transport. Both a single rainfall event and seasonal rainfall events were modeled. For the single rainfall event models, the vapor response process could be divided into three steps: namely, infiltration, water redistribution, and establishment of a water lens atop the groundwater source. In the infiltration step, rainfall intensity was found to determine the speed of the wetting front and wash-out effect on the vapor. The passage of the wetting front led to an increase of the vapor concentration in both the infiltration and water redistribution steps and this effect is noted at soil probes located 1m below the ground surface. When the mixing of groundwater with infiltrated water was not allowed, a clean water lens accumulated above the groundwater source and led to a capping effect which can reduce diffusion rates of contaminant from the source. Seasonal rainfall with short time intervals involved superposition of the individual rainfall events. This modeling results indicated that for relatively deeper soil that the infiltration wetting front could not flood, the effects were damped out in less than a month after rain; while in the long term (years), possible formation of a water lens played a larger role in determining

Magnetic activity at infrared frequencies in structured metallic photonic crystals

International Nuclear Information System (INIS)

O'Brien, S.; Pendry, J.P.

2002-01-01

We derive the effective permeability and permittivity of a nanostructured metallic photonic crystal by analysing the complex reflection and transmission coefficients for slabs of various thicknesses. These quantities were calculated using the transfer matrix method. Our results indicate that these structures could be used to realize a negative effective permeability, at least up to infrared frequencies. The origin of the negative permeability is a resonance due to the internal inductance and capacitance of the structure. We also present an analytic model for the effective permeability of the crystal. The model reveals the importance of the inertial inductance due to the finite mass of the electrons in the metal. We find that this contribution to the inductance has implications for the design of metallic magnetic structures in the optical region of the spectrum. We show that the magnetic activity in the structure is accompanied by the concentration of the incident field energy into very small volumes within the structure. This property will allow us to considerably enhance non-linear effects with minute quantities of material. (author)

Interaction of alkali metal nitrates with calcium carbonate and kyanite

International Nuclear Information System (INIS)

Protsyuk, A.P.; Malakhov, A.I.; Karabanov, V.P.; Lebedeva, L.P.

1978-01-01

Thermographic, thermodynamic and X-ray phase studies have been made into the interaction of alkali metal nitrates with calcium carbonate and kyanite. Examined among other things was the effect of water vapor and carbon dioxide on the interaction between alkali metal nitrates and kyanite. The chemical mechanism of the occurring processes has been established. The interaction with calcium carbonates results in the formation of alkali metal carbonates and calcium oxide with liberation of nitrogen oxide and oxygen. The products of the interaction with kyanite are shown to be identical with the compounds forming when alkali metal carbonates are used

A high-throughput solid-phase extraction microchip combined with inductively coupled plasma-mass spectrometry for rapid determination of trace heavy metals in natural water.

Science.gov (United States)

Shih, Tsung-Ting; Hsieh, Cheng-Chuan; Luo, Yu-Ting; Su, Yi-An; Chen, Ping-Hung; Chuang, Yu-Chen; Sun, Yuh-Chang

2016-04-15

Herein, a hyphenated system combining a high-throughput solid-phase extraction (htSPE) microchip with inductively coupled plasma-mass spectrometry (ICP-MS) for rapid determination of trace heavy metals was developed. Rather than performing multiple analyses in parallel for the enhancement of analytical throughput, we improved the processing speed for individual samples by increasing the operation flow rate during SPE procedures. To this end, an innovative device combining a micromixer and a multi-channeled extraction unit was designed. Furthermore, a programmable valve manifold was used to interface the developed microchip and ICP-MS instrumentation in order to fully automate the system, leading to a dramatic reduction in operation time and human error. Under the optimized operation conditions for the established system, detection limits of 1.64-42.54 ng L(-1) for the analyte ions were achieved. Validation procedures demonstrated that the developed method could be satisfactorily applied to the determination of trace heavy metals in natural water. Each analysis could be readily accomplished within just 186 s using the established system. This represents, to the best of our knowledge, an unprecedented speed for the analysis of trace heavy metal ions. Copyright © 2016 Elsevier B.V. All rights reserved.

Dynamic interactions of Leidenfrost droplets on liquid metal surface

Science.gov (United States)

Ding, Yujie; Liu, Jing

2016-09-01

Leidenfrost dynamic interaction effects of the isopentane droplets on the surface of heated liquid metal were disclosed. Unlike conventional rigid metal, such conductive and deformable liquid metal surface enables the levitating droplets to demonstrate rather abundant and complex dynamics. The Leidenfrost droplets at different diameters present diverse morphologies and behaviors like rotation and oscillation. Depending on the distance between the evaporating droplets, they attract and repulse each other through the curved surfaces beneath them and their vapor flows. With high boiling point up to 2000 °C, liquid metal offers a unique platform for testing the evaporating properties of a wide variety of liquid even solid.

Low-leakage-current AlGaN/GaN HEMTs on Si substrates with partially Mg-doped GaN buffer layer by metal organic chemical vapor deposition

International Nuclear Information System (INIS)

Li Ming; Wang Yong; Wong Kai-Ming; Lau Kei-May

2014-01-01

High-performance low-leakage-current AlGaN/GaN high electron mobility transistors (HEMTs) on silicon (111) substrates grown by metal organic chemical vapor deposition (MOCVD) with a novel partially Magnesium (Mg)-doped GaN buffer scheme have been fabricated successfully. The growth and DC results were compared between Mg-doped GaN buffer layer and a unintentionally one. A 1-μm gate-length transistor with Mg-doped buffer layer exhibited an OFF-state drain leakage current of 8.3 × 10 −8 A/mm, to our best knowledge, which is the lowest value reported for MOCVD-grown AlGaN/GaN HEMTs on Si featuring the same dimension and structure. The RF characteristics of 0.25-μm gate length T-shaped gate HEMTs were also investigated

Improved crystal quality of a-plane GaN with high- temperature 3-dimensional GaN buffer layers deposited by using metal-organic chemical vapor deposition

International Nuclear Information System (INIS)

Park, Sung Hyun; Moon, Dae Young; Kim, Bum Ho; Kim, Dong Uk; Chang, Ho Jun; Jeon, Heon Su; Yoon, Eui Joon; Joo, Ki Su; You, Duck Jae; Nanishi, Yasushi

2012-01-01

a-plane GaN on r-plane sapphire substrates suffers from high density defects and rough surfaces. To obtain pit-free a-plane GaN by metal-organic chemical vapor deposition, we intentionally grew high-temperature (HT) 3-dimensional (3D) GaN buffer layers on a GaN nucleation layer. The effects of the HT 3D GaN buffer layers on crystal quality and the surface morphology of a-plane GaN were studied. The insertion of a 3D GaN buffer layer with an optimum thickness was found to be an effective method to obtain pit-free a-plane GaN with improved crystalline quality on r-plane sapphire substrates. An a-plane GaN light emitting diode (LED) at an emission wavelength around 480 nm with negligible peak shift was successfully fabricated.

Inductively coupled plasma source mass spectrometry

International Nuclear Information System (INIS)

Price Russ, G. III

1993-01-01

Inductively coupled plasma source mass spectrometry (ICP-MS) is a relatively new (5 y commercial availability) technique for simultaneously determining the concentration and isotopic composition of a large number of elements at trace levels. The principle advantages of ICP-MS are the ability to measure essentially all the metallic elements at concentrations as low as 1 part in 10 12 by weight, to analyse aqueous samples directly, to determine the isotopic composition of essentially all the metallic elements, and to analyse samples rapidly (minutes). The history of the development of ICP-MS and discussions of a variety of applications have been discussed in detail in Date and Gray (1988). Koppenaal (1988, 1990) has reviewed the ICP-MS literature. In that ICP-MS is a relatively new and still evolving technique, this chapter will discuss potential capability more than proven performance. (author). 24 refs

Investigation into metal contamination of the Berg River, Western ...

African Journals Online (AJOL)

The nitric acid digestion technique was used to extract metals from water, sediment and biofilm samples collected at various points (Site A . agricultural area, Site B . informal settlement and Site C . Newton pumping station) along the Berg River. Metal concentrations were determined using inductively coupled plasma atomic ...

Formation of amorphous metal alloys by chemical vapor deposition

Science.gov (United States)

Mullendore, A.W.

1988-03-18

Amorphous alloys are deposited by a process of thermal dissociation of mixtures of organometallic compounds and metalloid hydrides,e.g., transition metal carbonyl, such as nickel carbonyl and diborane. Various sizes and shapes of deposits can be achieved, including near-net-shape free standing articles, multilayer deposits, and the like. Manipulation or absence of a magnetic field affects the nature and the structure of the deposit. 1 fig.

Boron-doped zinc oxide thin films for large-area solar cells grown by metal organic chemical vapor deposition

International Nuclear Information System (INIS)

Chen, X.L.; Xu, B.H.; Xue, J.M.; Zhao, Y.; Wei, C.C.; Sun, J.; Wang, Y.; Zhang, X.D.; Geng, X.H.

2007-01-01

Boron-doped zinc oxide (ZnO:B) films were grown by metal organic chemical vapor deposition using diethylzinc (DEZn), and H 2 O as reactant gases and diborane (B 2 H 6 ) as an n-type dopant gas. The structural, electrical and optical properties of ZnO films doped at different B 2 H 6 flow rates were investigated. X-ray diffraction spectra and scanning electron microscopy images indicate that boron-doping plays an important role on the microstructure of ZnO films, which induced textured morphology. With optimized conditions, low sheet resistance (∼ 30 Ω/□), high transparency (> 85% in the visible light and infrared range) and high mobility (17.8 cm 2 V -1 s -1 ) were obtained for 700-nm ZnO:B films deposited on 20 cm x 20 cm glass substrates at the temperature of 443 K. After long-term exposure in air, the ZnO:B films also showed a better electrical stability than the un-doped samples. With the application of ZnO:B/Al back contacts, the short circuit current density was effectively enhanced by about 3 mA/cm 2 for a small area a-Si:H cell and a high efficiency of 9.1% was obtained for a large-area (20 cm x 20 cm) a-Si solar module

Plasma-enhanced chemical vapor deposition for YBCO film fabrication of superconducting fault-current limiter

Energy Technology Data Exchange (ETDEWEB)

Jun, Byung Hyuk; Kim, Chan Joong

2006-05-15

Since the high-temperature superconductor of oxide type was founded, many researches and efforts have been performed for finding its application field. The YBCO superconducting film fabricated on economic metal substrate with uniform critical current density is considered as superconducting fault-current limiter (SFCL). There are physical and chemical processes to fabricate superconductor film, and it is understood that the chemical methods are more economic to deposit large area. Among them, chemical vapor deposition (CVD) is a promising deposition method in obtaining film uniformity. To solve the problems due to the high deposition temperature of thermal CVD, plasma-enhanced chemical vapor deposition (PECVD) is suggested. This report describes the principle and fabrication trend of SFCL, example of YBCO film deposition by PECVD method, and principle of plasma deposition.

Vapor Pressure Data Analysis and Statistics

Science.gov (United States)

2016-12-01

near 8, 2000, and 200, respectively. The A (or a) value is directly related to vapor pressure and will be greater for high vapor pressure materials...1, (10) where n is the number of data points, Yi is the natural logarithm of the i th experimental vapor pressure value, and Xi is the...VAPOR PRESSURE DATA ANALYSIS AND STATISTICS ECBC-TR-1422 Ann Brozena RESEARCH AND TECHNOLOGY DIRECTORATE