Mo-containing tetrahedral amorphous carbon deposited by dual filtered cathodic vacuum arc with selective pulsed bias voltage

International Nuclear Information System (INIS)

Pasaja, Nitisak; Sansongsiri, Sakon; Intarasiri, Saweat; Vilaithong, Thiraphat; Anders, Andre

2007-01-01

Metal-containing tetrahedral amorphous carbon films were produced by dual filtered cathodic vacuum arc plasma sources operated in sequentially pulsed mode. Negatively pulsed bias was applied to the substrate when carbon plasma was generated, whereas it was absent when the molybdenum plasma was presented. Film thickness was measured after deposition by profilometry. Glass slides with silver pads were used as substrates for the measurement of the sheet resistance. The microstructure and composition of the films were characterized by Raman spectroscopy and Rutherford backscattering, respectively. It was found that the electrical resistivity decreases with an increase of the Mo content, which can be ascribed to an increase of the sp 2 content and an increase of the sp 2 cluster size

Effects of ion implantation on the microstructure and residual stress of filter arc CrN films

International Nuclear Information System (INIS)

Weng, K.-W.; Chen, Y.-C.; Han Sheng; Hsu, C.-S.; Chen, Y.-L.; Wang, D.-Y.

2008-01-01

Chromium nitride coatings were deposited using a hybrid physical vapor deposition (PVD) system containing a filter arc deposition (FAD) and a metal plasma ion implantation source (MPII). Exactly how surface residual stress affects film characteristics is investigated using glancing incident X-ray diffraction (GIXRD) and pole figure analyses. Compared with unimplanted CrN, implanted carbon typically increases compressive residual stress and hardness. Wear resistance was also improved by implanted carbon

Influence of substrate bias on the structure and properties of (Ti, Al)N films deposited by filtered cathodic vacuum arc

International Nuclear Information System (INIS)

Cheng, Y.H.; Tay, B.K.; Lau, S.P.; Shi, X.

2001-01-01

(Ti, Al)N films were deposited by an off-plane, double-bend, filtered cathodic vacuum arc technique in N 2 atmosphere at room temperature. The (Ti, Al)N films deposited are atomically smooth. The influence of substrate negative bias at the wide range (0-1000 V) on the deposition rate, surface morphology, crystal structure, internal stress, and mechanical properties of (Ti, Al)N films were systematically studied. Increasing substrate bias results in the decrease of deposition rate and the increase of surface roughness monotonically. At the bias of 0 V, (Ti, Al)N films are amorphous, and the internal stress, hardness, and Young's modulus for the deposited films are fairly low. With increasing substrate bias to 200 V, single-phase face-centered cubic-type nanocrystalline (Ti, Al)N films can be obtained, and the internal stress, hardness, and Young's modulus increase to the maximum of 7 GPa, 28 GPa, and 240 GPa, respectively. Further increase of substrate bias results in the decrease of intensity and the broadening of x-ray diffraction lines, and the gradual decrease of internal stress, hardness, and Young's modulus in (Ti, Al)N films

Nanodiamond embedded ta-C composite film by pulsed filtered vacuum arc deposition from a single target

Science.gov (United States)

Iyer, Ajai; Etula, Jarkko; Ge, Yanling; Liu, Xuwen; Koskinen, Jari

2016-11-01

Detonation Nanodiamonds (DNDs) are known to have sp3 core, sp2 shell, small size (few nm) and are gaining importance as multi-functional nanoparticles. Diverse methods have been used to form composites, containing detonation nanodiamonds (DNDs) embedded in conductive and dielectric matrices for various applications. Here we show a method, wherein DND-ta-C composite film, consisting of DNDs embedded in ta-C matrix have been co-deposited from the same cathode by pulsed filtered cathodic vacuum arc method. Transmission Electron Microscope analysis of these films revel the presence of DNDs embedded in the matrix of amorphous carbon. Raman spectroscopy indicates that the presence of DNDs does not adversely affect the sp3 content of DND-ta-C composite film compared to ta-C film of same thickness. Nanoindentation and nanowear tests indicate that DND-ta-C composite films possess improved mechanical properties in comparison to ta-C films of similar thickness.

Detection of arcing location on photovoltaic systems using filters

Science.gov (United States)

Johnson, Jay

2018-02-20

The present invention relates to photovoltaic systems capable of identifying the location of an arc-fault. In particular, such systems include a unique filter connected to each photovoltaic (PV) string, thereby providing a unique filtered noise profile associated with a particular PV string. Also described herein are methods for identifying and isolating such arc-faults.

Structural, nanomechanical and variable range hopping conduction behavior of nanocrystalline carbon thin films deposited by the ambient environment assisted filtered cathodic jet carbon arc technique

Energy Technology Data Exchange (ETDEWEB)

Panwar, O.S., E-mail: ospanwar@mail.nplindia.ernet.in [Polymorphic Carbon Thin Films Group, Physics of Energy Harvesting Division, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi - 110 012 (India); Rawal, Ishpal; Tripathi, R.K. [Polymorphic Carbon Thin Films Group, Physics of Energy Harvesting Division, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi - 110 012 (India); Srivastava, A.K. [Electron and Ion Microscopy, Sophisticated and Analytical Instruments, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi - 110 012 (India); Kumar, Mahesh [Ultrafast Opto-Electronics and Tetrahertz Photonics Group, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi - 110 012 (India)

2015-04-15

Highlights: • Nanocrystalline carbon thin films are grown by filtered cathodic jet carbon arc process. • Effect of gaseous environment on the properties of carbon films has been studied. • The structural and nanomechanical properties of carbon thin films have been studied. • The VRH conduction behavior in nanocrystalline carbon thin films has been studied. - Abstract: This paper reports the deposition and characterization of nanocrystalline carbon thin films by filtered cathodic jet carbon arc technique assisted with three different gaseous environments of helium, nitrogen and hydrogen. All the films are nanocrystalline in nature as observed from the high resolution transmission electron microscopic (HRTEM) measurements, which suggests that the nanocrystallites of size ∼10–50 nm are embedded though out the amorphous matrix. X-ray photoelectron spectroscopic studies suggest that the film deposited under the nitrogen gaseous environment has the highest sp{sup 3}/sp{sup 2} ratio accompanied with the highest hardness of ∼18.34 GPa observed from the nanoindentation technique. The film deposited under the helium gaseous environment has the highest ratio of the area under the Raman D peak to G peak (A{sub D}/A{sub G}) and the highest conductivity (∼2.23 S/cm) at room temperature, whereas, the film deposited under the hydrogen environment has the lowest conductivity value (2.27 × 10{sup −7} S/cm). The temperature dependent dc conduction behavior of all the nanocrystalline carbon thin films has been analyzed in the light of Mott’s variable range hopping (VRH) conduction mechanism and observed that all the films obey three dimension VRH conduction mechanism for the charge transport.

Ion kinetic energy distribution in a pulsed vacuum arc with a straight magnetic filter

International Nuclear Information System (INIS)

Giuliani, L; Grondona, D; Kelly, H; Minotti, F

2008-01-01

In vacuum arcs of interest for film deposition the ion kinetic energy is of importance because it influences the coating properties. In this kind of discharge, the ions come out from the cathode spots with a high kinetic energy (20-150 eV). In the present work, we present measurements of vacuum arc ion energy distributions in a pulsed vacuum arc with a straight magnetic filter. A retarding field analyser (RFA) was used to perform the measurements that were carried out with a variable magnetic field strength (of the order of 10 mT). Since the interpretation of the results obtained from the RFA lies in the knowledge of the plasma and floating potential values, we have employed also Langmuir probes for determining those quantities. The obtained results for the ion kinetic energy are similar to those reported by other authors, but they were also found to be independent of the magnetic field strength. The electron temperature was also found to be independent of the magnetic field strength and of the axial position along the filter, indicating the absence of collisions.

Interface control of atomic layer deposited oxide coatings by filtered cathodic arc deposited sublayers for improved corrosion protection

Energy Technology Data Exchange (ETDEWEB)

Härkönen, Emma, E-mail: emma.harkonen@helsinki.fi [Laboratory of Inorganic Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki (Finland); Tervakangas, Sanna; Kolehmainen, Jukka [DIARC-Technology Inc., Espoo (Finland); Díaz, Belén; Światowska, Jolanta; Maurice, Vincent; Seyeux, Antoine; Marcus, Philippe [Laboratoire de Physico-Chimie des Surfaces, CNRS (UMR 7075) – Chimie ParisTech (ENSCP), F-75005 Paris (France); Fenker, Martin [FEM Research Institute, Precious Metals and Metals Chemistry, D-73525 Schwäbisch Gmünd (Germany); Tóth, Lajos; Radnóczi, György [Research Centre for Natural Sciences HAS, (MTA TKK), Budapest (Hungary); Ritala, Mikko [Laboratory of Inorganic Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki (Finland)

2014-10-15

Sublayers grown with filtered cathodic arc deposition (FCAD) were added under atomic layer deposited (ALD) oxide coatings for interface control and improved corrosion protection of low alloy steel. The FCAD sublayer was either Ta:O or Cr:O–Ta:O nanolaminate, and the ALD layer was Al{sub 2}O{sub 3}–Ta{sub 2}O{sub 5} nanolaminate, Al{sub x}Ta{sub y}O{sub z} mixture or graded mixture. The total thicknesses of the FCAD/ALD duplex coatings were between 65 and 120 nm. Thorough analysis of the coatings was conducted to gain insight into the influence of the FCAD sublayer on the overall coating performance. Similar characteristics as with single FCAD and ALD coatings on steel were found in the morphology and composition of the duplex coatings. However, the FCAD process allowed better control of the interface with the steel by reducing the native oxide and preventing its regrowth during the initial stages of the ALD process. Residual hydrocarbon impurities were buried in the interface between the FCAD layer and steel. This enabled growth of ALD layers with improved electrochemical sealing properties, inhibiting the development of localized corrosion by pitting during immersion in acidic NaCl and enhancing durability in neutral salt spray testing. - Highlights: • Corrosion protection properties of ALD coatings were improved by FCAD sublayers. • The FCAD sublayer enabled control of the coating-substrate interface. • The duplex coatings offered improved sealing properties and durability in NSS. • The protective properties were maintained during immersion in a corrosive solution. • The improvements were due to a more ideal ALD growth on the homogeneous FCAD oxide.

Preparation and investigation of diamond-like carbon stripper foils by filtered cathodic vacuum arc

International Nuclear Information System (INIS)

Fan, Qiwen; Du, Yinghui; Zhang, Rong; Xu, Guoji

2013-01-01

Thin diamond-like carbon (DLC) stripper foils ∼5μg/cm 2 in thickness were produced and evaluated as heavy-ion strippers for the Beijing HI-13 Tandem Accelerator. The DLC layers ∼4μg/cm 2 in thickness were produced by the filtered cathodic vacuum arc technology onto glass slides coated with betaine–saccharose as releasing agent, which were previously covered with evaporated carbon layers ∼1μg/cm 2 in thickness by the controlled ac arc-discharge method. Irradiation lifetimes of the DLC stripper foils were tested using the heavy-ion beams at the terminal of the Beijing HI-13 Tandem Accelerator, and compared with those of the standard carbon stripper foils made by the combined dc and ac arc-discharge method. The measurements indicate that the DLC stripper foils outlast the standard combined dc and ac arc-discharge carbon stripper foils by a factor of at least 13 and 4 for the 197 Au − (∼9MeV, ∼1μA) and 63 Cu − (∼9MeV, ∼1μA) ion beams, respectively. The structure and properties of the DLC foils deposited onto silicon substrates by the filtered cathodic vacuum arc technology were also evaluated and analyzed by scanning electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. The scanning electron microscopy images show that the DLC foils contain hardly droplets through the double 90° filters. The X-ray photoelectron spectrum indicates that sp 3 bonds of the DLC foils exceed 70%. The integral intensity ratio of the D peak to the G peak (I D /I G ) measured by the Raman spectroscopy is 0.78

MeV-ion beam analysis of the interface between filtered cathodic arc-deposited a-carbon and single crystalline silicon

International Nuclear Information System (INIS)

Kamwanna, T.; Pasaja, N.; Yu, L.D.; Vilaithong, T.; Anders, A.; Singkarat, S.

2008-01-01

Amorphous carbon (a-C) films were deposited on Si(1 0 0) wafers by a filtered cathodic vacuum arc (FCVA) plasma source. A negative electrical bias was applied to the silicon substrate in order to control the incident energy of carbon ions. Effects of the electrical bias on the a-C/Si interface characteristics were investigated by using standard Rutherford backscattering spectrometry (RBS) in the channeling mode with 2.1-MeV He 2+ ions. The shape of the Si surface peaks of the RBS/channeling spectra reflects the degree of interface disorder due to atomic displacement from the bulk position of the Si crystal. Details of the analysis method developed are described. It was found that the width of the a-C/Si interface increases linearly with the substrate bias voltage but not the thickness of the a-C film.

Influence of thermal heating on diamond-like carbon film properties prepared by filtered cathodic arc

International Nuclear Information System (INIS)

Khamnualthong, N.; Siangchaew, K.; Limsuwan, P.

2013-01-01

Tetrahedral amorphous diamond-like carbon (ta-DLC) films were deposited on magnetic recording heads using the filtered cathodic arc method. The deposited film thickness was on the order of several nanometers. The DLC films were then annealed to 100 °C–300 °C for 30 and 60 min, and the structure of the ta-DLC films was investigated using Raman spectroscopy, where the gross changes were observed in the Raman D and G peaks. Detailed interpretation concluded that there was sp 2 clustering as a function of temperature, and there was no sp 3 -to-sp 2 conversion after heating up to 300 °C. Furthermore, X-ray photoelectron spectroscopy suggested that oxidation of both the ta-DLC film and the adhesion layer occurs at 300 °C. Additionally, more film wear was observed with heating as measured by a nanoindenter. - Highlights: • Tetrahedral-amorphous diamond-like carbon (ta-DLC) by filtered cathodic arc • ta-DLC used in magnetic recording head as head overcoat • ta-DLC thickness range of less than 2 nm • ta-DLC property dependence on heating • Temperature effect range of up to 300 °C

Direct-current cathodic vacuum arc system with magnetic-field mechanism for plasma stabilization.

Science.gov (United States)

Zhang, H-S; Komvopoulos, K

2008-07-01

Filtered cathodic vacuum arc (FCVA) deposition is characterized by plasma beam directionality, plasma energy adjustment via substrate biasing, macroparticle filtering, and independent substrate temperature control. Between the two modes of FCVA deposition, namely, direct current (dc) and pulsed arc, the dc mode yields higher deposition rates than the pulsed mode. However, maintaining the dc arc discharge is challenging because of its inherent plasma instabilities. A system generating a special configuration of magnetic field that stabilizes the dc arc discharge during film deposition is presented. This magnetic field is also part of the out-of-plane magnetic filter used to focus the plasma beam and prevent macroparticle film contamination. The efficiency of the plasma-stabilizing magnetic-field mechanism is demonstrated by the deposition of amorphous carbon (a-C) films exhibiting significantly high hardness and tetrahedral carbon hybridization (sp3) contents higher than 70%. Such high-quality films cannot be produced by dc arc deposition without the plasma-stabilizing mechanism presented in this study.

Direct-current cathodic vacuum arc system with magnetic-field mechanism for plasma stabilization

International Nuclear Information System (INIS)

Zhang, H.-S.; Komvopoulos, K.

2008-01-01

Filtered cathodic vacuum arc (FCVA) deposition is characterized by plasma beam directionality, plasma energy adjustment via substrate biasing, macroparticle filtering, and independent substrate temperature control. Between the two modes of FCVA deposition, namely, direct current (dc) and pulsed arc, the dc mode yields higher deposition rates than the pulsed mode. However, maintaining the dc arc discharge is challenging because of its inherent plasma instabilities. A system generating a special configuration of magnetic field that stabilizes the dc arc discharge during film deposition is presented. This magnetic field is also part of the out-of-plane magnetic filter used to focus the plasma beam and prevent macroparticle film contamination. The efficiency of the plasma-stabilizing magnetic-field mechanism is demonstrated by the deposition of amorphous carbon (a-C) films exhibiting significantly high hardness and tetrahedral carbon hybridization (sp 3 ) contents higher than 70%. Such high-quality films cannot be produced by dc arc deposition without the plasma-stabilizing mechanism presented in this study

Fabrication of nitrogen-containing diamond-like carbon film by filtered arc deposition as conductive hard-coating film

Science.gov (United States)

Iijima, Yushi; Harigai, Toru; Isono, Ryo; Imai, Takahiro; Suda, Yoshiyuki; Takikawa, Hirofumi; Kamiya, Masao; Taki, Makoto; Hasegawa, Yushi; Tsuji, Nobuhiro; Kaneko, Satoru; Kunitsugu, Shinsuke; Habuchi, Hitoe; Kiyohara, Shuji; Ito, Mikio; Yick, Sam; Bendavid, Avi; Martin, Phil

2018-01-01

Diamond-like carbon (DLC) films, which are amorphous carbon films, have been used as hard-coating films for protecting the surface of mechanical parts. Nitrogen-containing DLC (N-DLC) films are expected as conductive hard-coating materials. N-DLC films are expected in applications such as protective films for contact pins, which are used in the electrical check process of integrated circuit chips. In this study, N-DLC films are prepared using the T-shaped filtered arc deposition (T-FAD) method, and film properties are investigated. Film hardness and film density decreased when the N content increased in the films because the number of graphite structures in the DLC film increased as the N content increased. These trends are similar to the results of a previous study. The electrical resistivity of N-DLC films changed from 0.26 to 8.8 Ω cm with a change in the nanoindentation hardness from 17 to 27 GPa. The N-DLC films fabricated by the T-FAD method showed high mechanical hardness and low electrical resistivity.

Incidence Angle Effect of Energetic Carbon Ions on Deposition Rate, Topography, and Structure of Ultrathin Amorphous Carbon Films Deposited by Filtered Cathodic Vacuum Arc

KAUST Repository

Wang, N.; Komvopoulos, K.

2012-01-01

The effect of the incidence angle of energetic carbon ions on the thickness, topography, and structure of ultrathin amorphous carbon (a-C) films synthesized by filtered cathodic vacuum arc (FCVA) was examined in the context of numerical

Effect of Coil Current on the Properties of Hydrogenated DLC Coatings Fabricated by Filtered Cathodic Vacuum Arc Technique

Science.gov (United States)

Liao, Bin; Ouyang, Xiaoping; Zhang, Xu; Wu, Xianying; Bian, Baoan; Ying, Minju; Jianwu, Liu

2018-01-01

We successfully prepared hydrogenated DLC (a-C:H) with a thickness higher than 25 μm on stainless steel using a filtered cathode vacuum arc (FCVA) technique. The structural and mechanical properties of DLC were systematically analyzed using different methods such as x-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy, Vickers hardness, nanohardness, and friction and wear tests. The effect of coil current on the arc voltage, ion current, and mechanical properties of resultant films was systematically investigated. The novelty of this study is the fabrication of DLC with Vickers hardness higher than 1500 HV, in the meanwhile with the thickness higher than 30 μm through varying the coil current with FCVA technique. The results indicated that the ion current, deposition rate, friction coefficient, and Vickers hardness of DLC were significantly affected by the magnetic field inside the filtered duct.

Synthesis and characterization of Ti-Si-C-N nanocomposite coatings prepared by a filtered vacuum arc method

Energy Technology Data Exchange (ETDEWEB)

Thangavel, Elangovan, E-mail: t.elangophy@gmail.com [Advanced Thin Film Research Group, Materials Processing Division, Korea Institute of Materials Science, Changwon 641-831 (Korea, Republic of); Center for Nano-Wear, Yonsei University, Seoul 120-749 (Korea, Republic of); Lee, Seunghun; Nam, Kee-Seok; Kim, Jong-Kuk [Advanced Thin Film Research Group, Materials Processing Division, Korea Institute of Materials Science, Changwon 641-831 (Korea, Republic of); Kim, Do-Geun, E-mail: dogeunkim@kims.re.kr [Advanced Thin Film Research Group, Materials Processing Division, Korea Institute of Materials Science, Changwon 641-831 (Korea, Republic of)

2013-01-15

Highlights: Black-Right-Pointing-Pointer Preparation method was used as filtered vacuum arc (FVA) deposition. Black-Right-Pointing-Pointer Ternary coating obtained by using single carbon source with TMS gas. Black-Right-Pointing-Pointer Detailed discussion of chemical nature for these coating by using XPS. - Abstract: Ti-Si-C-N nanocomposite coatings were synthesized by a filtered vacuum arc (FVA) technique. A metal organic precursor, tetramethylsilane (TMS), was used as a source for silicon and carbon to deposit the Ti-Si-C-N nanocomposite coating with a Ti cathode source. The chemical and microstructural properties of the as-deposited coatings were systematically investigated using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and transmission electron microscopy (TEM). Nanoindentation and scratch tests were carried out to evaluate the mechanical and adhesion properties of the coatings. From the XPS analysis, it was found that the Si content in the coating increased from 2 to 16 at.% as the TMS flow rate was increased from 5 to 20 sccm. The TEM analysis clearly demonstrated that the coatings were composed of crystalline TiCN along with amorphous Si{sub 3}N{sub 4} as a secondary phase. From the XRD results, it was found that the crystallite size of TiCN increased with increasing Si content. The microstructure and mechanical properties of the TiSiCN coatings prepared by this method exhibited strong dependencies on the silicon content. A maximum hardness of 49 GPa and a coefficient of friction of 0.17 were obtained for the film with a silicon content of 3 at.%.

Raman Spectroscopy of DLC/a-Si Bilayer Film Prepared by Pulsed Filtered Cathodic Arc

Directory of Open Access Journals (Sweden)

C. Srisang

2012-01-01

Full Text Available DLC/a-Si bilayer film was deposited on germanium substrate. The a-Si layer, a seed layer, was firstly deposited on the substrate using DC magnetron sputtering and DLC layer was then deposited on the a-Si layer using pulsed filtered cathodic arc method. The bilayer films were deposited with different DLC/a-Si thickness ratios, including 2/2, 2/6, 4/4, 6/2, and 9/6. The effect of DLC/a-Si thickness ratios on the sp3 content of DLC was analyzed by Raman spectroscopy. The results show that a-Si layer has no effect on the structure of DLC film. Furthermore, the upper shift in G wavenumber and the decrease in ID/IG inform that sp3 content of the film is directly proportional to DLC thickness. The plot modified from the three-stage model informed that the structural characteristics of DLC/a-Si bilayer films are located close to the tetrahedral amorphous carbon. This information may be important for analyzing and developing bilayer protective films for future hard disk drive.

Incidence Angle Effect of Energetic Carbon Ions on Deposition Rate, Topography, and Structure of Ultrathin Amorphous Carbon Films Deposited by Filtered Cathodic Vacuum Arc

KAUST Repository

Wang, N.

2012-07-01

The effect of the incidence angle of energetic carbon ions on the thickness, topography, and structure of ultrathin amorphous carbon (a-C) films synthesized by filtered cathodic vacuum arc (FCVA) was examined in the context of numerical and experimental results. The thickness of a-C films deposited at different incidence angles was investigated in the light of Monte Carlo simulations, and the calculated depth profiles were compared with those obtained from high-resolution transmission electron microscopy (TEM). The topography and structure of the a-C films were studied by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS), respectively. The film thickness decreased with the increase of the incidence angle, while the surface roughness increased and the content of tetrahedral carbon hybridization (sp 3) decreased significantly with the increase of the incidence angle above 45° , measured from the surface normal. TEM, AFM, and XPS results indicate that the smoothest and thinnest a-C films with the highest content of sp 3 carbon bonding were produced for an incidence angle of 45°. The findings of this study have direct implications in ultrahigh-density magnetic recording, where ultrathin and smooth a-C films with high sp 3 contents are of critical importance. © 2012 IEEE.

Influences of arc current on composition and properties of MgO thin films prepared by cathodic vacuum arc deposition

International Nuclear Information System (INIS)

Zhu Daoyun; Zheng Changxi; Wang Mingdong; Liu Yi; Chen Dihu; He Zhenhui; Wen Lishi; Cheung, W.Y.

2010-01-01

MgO thin films with high optical transmittances (more than 90%) were prepared by cathodic vacuum arc deposition technique. With the increase of arc current from 40 to 80 A, the deposition pressure decreases and the film thickness increases; the atomic ratio of Mg/O in MgO thin films (obtained by RBS) increases from 0.97 to 1.17, giving that deposited at 50 A most close to the stoichiometric composition of the bulk MgO; the grains of MgO thin films grow gradually as shown in SEM images. XRD patterns show that MgO (1 1 0) orientation is predominant for films prepared at the arc currents ranged from 50 to 70 A. The MgO (1 0 0) orientation is much enhanced and comparable to that of MgO (1 1 0) for films prepared at the arc current of 80 A. The secondary electron emission coefficient of MgO thin film increases with arc current ranged from 50 to 70 A.

Physical-mechanical properties of Ti-Al-N films, deposited from mixed two-component vacuum arc plasma stream

International Nuclear Information System (INIS)

Aksenov, D.S.; Aksenov, I.I.; Luchaninov, A.A.; Reshetnyak, E.N.; Strel'nitskij, V.E.; Tolmacheva, G.N.; Yurkov, S.A.

2011-01-01

Ti-Al-N films were obtained by vacuum arc system equipped with two-channel T-shaped magnetic filter. The films were deposited by mixing of filtered plasma streams from two sources with cathodes made of aluminium and titanium in nitrogen environment. An influence of aluminium concentration and substrate bias on structure, hardness and elastic modulus of deposited films was studied by X-ray diffraction analysis and nanoindentation techniques. It was found that coatings with aluminium content in range from 13 to 47 at. % are characterized by cubic nitride based on TiN with NaCl structure. An increase of Al content to 71 at. % leads to the formation of hexagonal AlN-based nitride with wurtzite-like structure. Maximum hardness of 35 GPa is observed in films with 47 at. % aluminium concentration and -100 V substrate bias. Elastic modulus falls off along with increase of Al content and negative substrate bias.

Effect of high substrate bias and hydrogen and nitrogen incorporation on filtered cathodic vacuum arc deposited tetrahedral amorphous carbon films

International Nuclear Information System (INIS)

Panwar, O.S.; Khan, Mohd. Alim; Kumar, Mahesh; Shivaprasad, S.M.; Satyanarayana, B.S.; Dixit, P.N.; Bhattacharyya, R.; Khan, M.Y.

2008-01-01

The application of a sufficiently high negative substrate bias, during the growth of tetrahedral amorphous carbon (ta-C), is usually associated with low sp 3 bonding configuration and stressed films. However, in an effort to understand and utilize the higher pseudo thermo dynamical conditions during the film growth, at high negative substrate bias (- 300 V), reported here is a study on ta-C films grown under different hydrogen and nitrogen concentration. As grown ta-C films were studied under different negative substrate bias conditions. The variation of the sp 3 content and sp 3 /sp 2 ratio in the ta-C films exhibits a trend similar to those reported in literature, with a subtle variation in this report being the substrate bias voltage, which was observed to be around - 200 V, for obtaining the highest sp 3 (80%) bonding and sp 3 /sp 2 (3.95) ratio. The hydrogen and nitrogen incorporated ta-C films studied, at a bias of - 300 V, show an increase in sp 3 (87-91%) bonding and sp 3 /sp 2 (7-10) ratio in the range of studies reported. The inference is drawn on the basis of the set of data obtained from measurements carried out using X-ray photoelectron spectroscopy, X-ray induced Auger electron spectroscopy and Raman spectroscopy of as grown and hydrogen and nitrogen incorporated ta-C films deposited using an S bend filtered cathodic vacuum arc system. The study indicates the possibility of further tailoring ta-C film properties and also extending capabilities of the cathodic arc system for developing carbon based films for electronics and tribological applications

Effect of high substrate bias and hydrogen and nitrogen incorporation on filtered cathodic vacuum arc deposited tetrahedral amorphous carbon films

Energy Technology Data Exchange (ETDEWEB)

Panwar, O.S. [Plasma Processed Materials Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi-110 012 (India)], E-mail: ospanwar@mail.nplindia.ernet.in; Khan, Mohd. Alim [Plasma Processed Materials Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi-110 012 (India); Kumar, Mahesh; Shivaprasad, S.M. [Surface Physics and Nanostructures Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi-110 012 (India); Satyanarayana, B.S. [MIT Innovation Centre and Electronics and Communication Department, Manipal Institute of Technology, Manipal-579104 (India); Dixit, P.N. [Plasma Processed Materials Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi-110 012 (India); Bhattacharyya, R. [Emeritus Scientist, National Physical Laboratory, New Delhi-110012 (India); Khan, M.Y. [Department of Physics, Jamia Millia Islamia, Central University, New Delhi-110025 (India)

2008-02-29

The application of a sufficiently high negative substrate bias, during the growth of tetrahedral amorphous carbon (ta-C), is usually associated with low sp{sup 3} bonding configuration and stressed films. However, in an effort to understand and utilize the higher pseudo thermo dynamical conditions during the film growth, at high negative substrate bias (- 300 V), reported here is a study on ta-C films grown under different hydrogen and nitrogen concentration. As grown ta-C films were studied under different negative substrate bias conditions. The variation of the sp{sup 3} content and sp{sup 3}/sp{sup 2} ratio in the ta-C films exhibits a trend similar to those reported in literature, with a subtle variation in this report being the substrate bias voltage, which was observed to be around - 200 V, for obtaining the highest sp{sup 3} (80%) bonding and sp{sup 3}/sp{sup 2} (3.95) ratio. The hydrogen and nitrogen incorporated ta-C films studied, at a bias of - 300 V, show an increase in sp{sup 3} (87-91%) bonding and sp{sup 3}/sp{sup 2} (7-10) ratio in the range of studies reported. The inference is drawn on the basis of the set of data obtained from measurements carried out using X-ray photoelectron spectroscopy, X-ray induced Auger electron spectroscopy and Raman spectroscopy of as grown and hydrogen and nitrogen incorporated ta-C films deposited using an S bend filtered cathodic vacuum arc system. The study indicates the possibility of further tailoring ta-C film properties and also extending capabilities of the cathodic arc system for developing carbon based films for electronics and tribological applications.

ZrN coatings deposited by high power impulse magnetron sputtering and cathodic arc techniques

Energy Technology Data Exchange (ETDEWEB)

Purandare, Yashodhan, E-mail: Y.Purandare@shu.ac.uk; Ehiasarian, Arutiun; Hovsepian, Papken [Nanotechnology Centre for PVD Research, Materials and Engineering Research Institute, Sheffield Hallam University, Sheffield S1 1WB (United Kingdom); Santana, Antonio [Ionbond AG Olten, Industriestrasse 211, CH-4600 Olten (Switzerland)

2014-05-15

Zirconium nitride (ZrN) coatings were deposited on 1 μm finish high speed steel and 316L stainless steel test coupons. Cathodic Arc (CA) and High Power Impulse Magnetron Sputtering (HIPIMS) + Unbalanced Magnetron Sputtering (UBM) techniques were utilized to deposit coatings. CA plasmas are known to be rich in metal and gas ions of the depositing species as well as macroparticles (droplets) emitted from the arc sports. Combining HIPIMS technique with UBM in the same deposition process facilitated increased ion bombardment on the depositing species during coating growth maintaining high deposition rate. Prior to coating deposition, substrates were pretreated with Zr{sup +} rich plasma, for both arc deposited and HIPIMS deposited coatings, which led to a very high scratch adhesion value (L{sub C2}) of 100 N. Characterization results revealed the overall thickness of the coatings in the range of 2.5 μm with hardness in the range of 30–40 GPa depending on the deposition technique. Cross-sectional transmission electron microscopy and tribological experiments such as dry sliding wear tests and corrosion studies have been utilized to study the effects of ion bombardment on the structure and properties of these coatings. In all the cases, HIPIMS assisted UBM deposited coating fared equal or better than the arc deposited coatings, the reasons being discussed in this paper. Thus H+U coatings provide a good alternative to arc deposited where smooth, dense coatings are required and macrodroplets cannot be tolerated.

Geochronology of the Thompson Creek Mo Deposit: Evidence for the Formation of Arc-related Mo Deposits

Science.gov (United States)

Lawrence, C. D.; Coleman, D. S.; Stein, H. J.

2016-12-01

The Thompson Creek Mo deposit in central ID, has been categorized as an arc-related Mo deposit due to the location, grade of Mo, and relative lack of enrichments in F, Rb, and Nb, compared to the Climax-type Mo deposits. Geochronology from this arc-related deposit provides an opportunity to compare and contrast magmatism, and mineralization to that in Climax-type deposits. Distinct pulses of magmatism were required to form the Thompson Creek Mo deposit, which is consistent with recent geochronology from Climax-type deposits. Molybdenite Re-Os geochronology from five veins requires at least three pulses of magmatism and mineralization between 89.39 +/- 0.37 and 88.47 +/- 0.16 Ma. Zircon U-Pb ages from these mineralized samples overlap with molybdenite mineralization, but show a much wider range (91.01 +/- 0.37 to 87.27 +/- 0.69). Previous work from Climax-type Mo deposits suggest a correlation between a super eruption, and the subsequent rapid (<1 Ma) onset, and completion of Mo mineralizing intrusions. The longer life (3-4 Ma) for the Thompson Creek Mo deposit suggests that the mineralizing intrusions for arc-related Mo deposits may not need to have as high [Mo] as the Climax-type deposits. This study also finds a shift in the source of magmatism from the pre- to syn-mineralizing intrusions. Zircons from pre-mineralizing intrusions have much higher (15-60 pg) concentrations of radiogenic Pb than zircons from mineralized intrusions, which all have less than 15 pg, though whole rock [U] are similar.

Regression Analysis of the Effect of Bias Voltage on Nano- and Macrotribological Properties of Diamond-Like Carbon Films Deposited by a Filtered Cathodic Vacuum Arc Ion-Plating Method

Directory of Open Access Journals (Sweden)

Shojiro Miyake

2014-01-01

Full Text Available Diamond-like carbon (DLC films are deposited by bend filtered cathodic vacuum arc (FCVA technique with DC and pulsed bias voltage. The effects of varying bias voltage on nanoindentation and nanowear properties were evaluated by atomic force microscopy. DLC films deposited with DC bias voltage of −50 V exhibited the greatest hardness at approximately 50 GPa, a low modulus of dissipation, low elastic modulus to nanoindentation hardness ratio, and high nanowear resistance. Nanoindentation hardness was positively correlated with the Raman peak ratio Id/Ig, whereas wear depth was negatively correlated with this ratio. These nanotribological properties highly depend on the films’ nanostructures. The tribological properties of the FCVA-DLC films were also investigated using a ball-on-disk test. The average friction coefficient of DLC films deposited with DC bias voltage was lower than that of DLC films deposited with pulse bias voltage. The friction coefficient calculated from the ball-on-disk test was correlated with the nanoindentation hardness in dry conditions. However, under boundary lubrication conditions, the friction coefficient and specific wear rate had little correlation with nanoindentation hardness, and wear behavior seemed to be influenced by other factors such as adhesion strength between the film and substrate.

Low pressure chemical vapour deposition of temperature resistant colour filters

International Nuclear Information System (INIS)

Verheijen, J.; Bongaerts, P.; Verspui, G.

1987-01-01

The possibility to deposit multilayer colour filters, based on optical inference, by means of Low Pressure Chemical Vapour Deposition (LPCVD) was investigated. The filters were made in a standard LPCVD system by alternate deposition of Si/sub 3/N/sub 4/ and SiO/sub 2/ layers. This resulted in filters with excellent colour uniformity on glass and quartz substrates. No difference was measured between theoretically calculated transmission and the transmission of the filters deposited by LPCVD. Temperature treatment at 600 0 C in air air showed no deterioration of filter quality and optical properties

Ultra-small platinum and gold nanoparticles by arc plasma deposition

International Nuclear Information System (INIS)

Kim, Sang Hoon; Jeong, Young Eun; Ha, Heonphil; Byun, Ji Young; Kim, Young Dok

2014-01-01

Highlights: • Ultra-small (<2 nm) and bigger platinum and gold nanoparticles were produced by arc plasma deposition (APD). • Size and coverage of deposited nanoparticles were easily controlled with APD parameters. • Crystalline structures of deposited nanoparticles emerged only when the particle size was bigger than ∼2 nm. - Abstract: Ultra-small (<2 nm) nanoparticles of platinum and gold were produced by arc plasma deposition (APD) in a systematic way and the deposition behavior was studied. Nanoparticles were deposited on two dimensional amorphous carbon and amorphous titania thin films and characterized by transmission electron microscopy (TEM). Deposition behavior of nanoparticles by APD was studied with discharge voltage (V), discharge condenser capacitance (C), and the number of plasma pulse shots (n) as controllable parameters. The average size of intrinsic nanoparticles generated by APD process was as small as 0.9 nm and deposited nanoparticles began to have crystal structures from the particle size of about 2 nm. V was the most sensitive parameter to control the size and coverage of generated nanoparticles compared to C and n. Size of APD deposited nanoparticles was also influenced by the nature of evaporating materials and substrates

Comparison of Several Modes in Simple ARC Second-Order Filter

Directory of Open Access Journals (Sweden)

A. I. Rybin

1994-07-01

Full Text Available In this paper the popular, multiple-feedback, ARC single opamp, highpass second-order filter is proposed in several types of modes, namely voltage, current and hybrid ones. These modes are studied and compared in detail. Computer experimental results are given supporting the theory.

Arc-related porphyry molybdenum deposit model: Chapter D in Mineral deposit models for resource assessment

Science.gov (United States)

Taylor, Ryan D.; Hammarstrom, Jane M.; Piatak, Nadine M.; Seal, Robert R.

2012-01-01

This report provides a descriptive model for arc-related porphyry molybdenum deposits. Presented within are geological, geochemical, and mineralogical characteristics that differentiate this deposit type from porphyry copper and alkali-feldspar rhyolite-granite porphyry molybdenum deposits. The U.S. Geological Survey's effort to update existing mineral deposit models spurred this research, which is intended to supplement previously published models for this deposit type that help guide mineral-resource and mineral-environmental assessments.

Effect of modulation periods on the microstructure and mechanical properties of DLC/TiC multilayer films deposited by filtered cathodic vacuum arc method

International Nuclear Information System (INIS)

Xu, Zhaoying; Sun, H.; Leng, Y.X.; Li, Xueyuan; Yang, Wenmao; Huang, N.

2015-01-01

Highlights: • DLC/TiC multilayer films with different modulation periods at same modulation ratio 1:1 were deposited by FCVA. • The residual stress of DLC/TiC multilayer films decreases with the modulation periods decrease. • The hardness of the multilayer DLC films decreases with modulation periods increasing. - Abstract: The high stress of diamond-like carbon (DLC) film limits its thickness and adhesion on substrate. Multilayer structure is one approach to overcome this disadvantage. In this paper, the DLC/TiC multilayer films with different modulation periods (80 nm, 106 nm or 160 nm) at same modulation ratio of 1:1 were deposited on Si(1 0 0) wafer and Ti-6Al-4V substrate by filtered cathodic vacuum arc (FCVA) technology. X-ray diffraction (XRD), transmission electron microscopy (TEM), nanoindention and wear test were employed to investigate the effect of modulation periods on the microstructure and mechanical properties of the multilayer films. The results showed that the residual stress of the DLC/TiC multilayer films could be effectively reduced and the residual stress decreased with the modulation periods decreasing. The hardness of the DLC/TiC multilayer films increased with modulation periods decreasing. The DLC/TiC multilayer film with modulation period of 106 nm had the best wear resistance due to the good combination of hardness, ductility and low compressive stress

LARGE AREA FILTERED ARC DEPOSITION OF CARBON AND BORON BASED HARD COATINGS

Energy Technology Data Exchange (ETDEWEB)

Bhattacharya, Rabi S.

2003-12-05

This document is a final report covering work performed under Contract No. DE-FG02-99ER82911 from the Department of Energy under a SBIR Phase II Program. Wear resistant, hard coatings can play a vital role in many engineering applications. The primary goal of this project was to develop coatings containing boron and carbon with hardness greater than 30 GPa and evaluate these coatings for machining applications. UES has developed a number of carbon and boron containing coatings with hardness in the range of 34 to 65 GPa using a combination of filtered cathodic arc and magnetron sputtering. The boron containing coatings were based on TiB2, TiBN, and TiBCN, while the carbon containing coatings ere TiC+C and hydrogen free diamond-like-carbon. Machining tests were performed with single and multilayer coated tools. The turning and milling tests were run at TechSolve Inc., under a subcontract at Ohio State University. Significant increases in tool lives were realized in end milling of H-13 die steel (8X) and titanium alloy (80%) using the TiBN coating. A multilayer TiBN/TiN performed the best in end-milling of highly abrasive Al-Si alloys. A 40% increase in life over the TiAlN benchmark coating was found. Further evaluations of these coatings with commercialization partners are currently in progress.

SU-E-T-153: Burst-Mode Modulated Arc Therapy with Flattening-Filter-Free Beams Versus Flattening-Filtered Beams

Energy Technology Data Exchange (ETDEWEB)

Kainz, K; Lawton, C; Li, X [Medical College of Wisconsin, Milwaukee, WI (United States)

2015-06-15

Purpose: To compare the dosimetry and delivery of burst-mode modulated arc radiotherapy using flattening-filter-free (FFF) and flattening-filtered (FF) beams. Methods: Burst-mode modulated arc therapy (mARC, Siemens) plans were generated for six prostate cases with FFF and FF beam models, using the Elekta Monaco v. 5.00 planning system. One 360-degree arc was used for five cases, and for one case two 360-degree coplanar arcs were used. The maximum number of optimization points (OPs) per arc was set to 91, and OPs with less than 4 MU were disregarded. All plans were delivered on the Siemens Artiste linear accelerator with 6MV FF (300 MU/min) and comparable-energy FFF (2000 MU/min, labeled as 7UF) beams. Results: For all cases studied, the plans with FFF beams exhibited DVHs for the PTV, rectum, and bladder that were nearly identical to those for the plans with FF beams. The FFF plan yielded reduced dose to the right femoral head for 5 cases, and lower mean dose to the left femoral head for 4 cases. For all but the two-arc case, the FFF and FF plans resulted in an identical number of segments. The total number of MUs was slightly lower for the FF plans for five cases. The total delivery time per fraction was substantially lower for the FFF plans, ranging from 25 to 50 percent among all cases, as compared to the FF plans. Conclusion: For mARC plans, FFF and FF beams provided comparable PTV coverage and rectum and bladder sparing. For the femoral heads, the mean dose was slightly lower in most cases when using the FFF beam. Although the flat beam plans typically required slightly fewer MUs, FFF beams required substantially less time to deliver a plan of similar quality. This work was supported by Siemens Medical Solutions and the MCW Cancer Center Fotsch Foundation.

Behaviour of gas conditions during vacuum arc discharges used for deposition of thin films

International Nuclear Information System (INIS)

Strzyzewski, J.; Langner, J.; Sadowski, M.; Witkowski, J.; Mirowski, R.; Catani, L.; Cianchi, A.; Russo, R.; Tazzari, S.

2005-01-01

The vacuum arc, which is one of the oldest techniques used for the deposition of thin films, is now widely used for the Plasma Immersion Ion Implantation and Deposition (PIII and D) in laboratory and industry. Despite of high progress in this field observed during last three decades, involving e.g. magnetic filters for the elimination of micro-droplets, some problems have not been resolved so far. The paper concerns an important problem which is connected with the inclusion of some impurities in the deposited metal film. It was found that appearance of contaminants in the film is induced mainly by water vapour remnants inside the vacuum chamber. The high adsorption of such contaminants by the deposited thin films is observed particularly in so-called getter materials, as niobium and titanium. Such materials can absorb impurities from the surrounding and dissolve them inside the layer. In order to eliminate this problem, in 2000 a new approach was proposed to perform arc discharges at the ultra-high vacuum (UHV) conditions. It was demonstrated experimentally that the deposited pure Nb-films have similar properties to the bulk-Nb samples. These results are very promising from the point of the application of such coating processes in super-conducting RF cavities of future charged-particle accelerators. The paper describes different methods used for the reduction of the background pressure in the UHV stand below 10 -10 hPa. The most important methods involve the selection of appropriate materials and the backing of whole vacuum system. In order to reduce the contaminants a laser triggering system has been applied instead of a common system, which used high-voltage discharges along the surface of an insulated trigger electrode. Particular attention is paid to a comparison of different gas conditions during arc discharges at high-vacuum conditions (background pressure in the range of 10 -8 -10 -7 hPa) and at UHV experiments (background pressure within the range of 10 -11

DC switch power supply for vacuum-arc coatings deposition

International Nuclear Information System (INIS)

Zalesskij, D.Yu.; Volkov, Yu.Ya.; Vasil'ev, V.V.; Kozhushko, V.V.; Luchaninov, A.A.; Strel'nitskij, V.E.

2008-01-01

Special DC Switch Power Supply for vacuum-arc deposition was developed and tested in the mode of depositing Al and AlN films. Maximum output power was 6 kW, maximum output current - 120 A, open-circuit voltage - 150 V. The Power Supply allows to adjust and stabilize output current in a wide range. Testing of the Power Supply revealed an advantages over the standard 'Bulat-6' power supply, especially for deposition of non-conductive AlN films.

Phase transitions of doped carbon in CrCN coatings with modified mechanical and tribological properties via filtered cathodic vacuum arc deposition

International Nuclear Information System (INIS)

Guan, J.J.; Wang, H.Q.; Qin, L.Z.; Liao, B.; Liang, H.; Li, B.

2017-01-01

The CrCN coatings were fabricated onto Si (1 1 1) wafers and SUS304 stainless steel plates using filtered cathodic vacuum arc deposition (FCVAD) technique under different flow ratios of N_2/C_2H_2 gas mixture. The morphology, crystalline structure and chemical composition of the coatings were characterized. It was found that the grain size reduce with increasing carbon content, which makes the CrCN coatings refined and smooth. The quasi-one-dimensional carbolite phase was also found in CrN host lattice with C_2H_2 content ranging from 5% to 20%, and it will be evolved into amorphous carbon and amorphous CN_x phases as C_2H_2 content exceeds 20%. Moreover, we examined the mechanical and tribological properties of the CrCN coatings, and the experimental results confirmed that the friction coefficient of the coatings descend to the lowest value as 0.39 with 30% C_2H_2 content, due to the graphite (sp"2 C−C) phase embed in CrN host lattice; while the chromium carbon (Cr_3C_2) and diamond (sp"3 C−C) phases may give rise to the increase of the coating hardness with the highest value at 23.97 GPa under 20% C_2H_2 content.

Phase transitions of doped carbon in CrCN coatings with modified mechanical and tribological properties via filtered cathodic vacuum arc deposition

Science.gov (United States)

Guan, J. J.; Wang, H. Q.; Qin, L. Z.; Liao, B.; Liang, H.; Li, B.

2017-04-01

The CrCN coatings were fabricated onto Si (1 1 1) wafers and SUS304 stainless steel plates using filtered cathodic vacuum arc deposition (FCVAD) technique under different flow ratios of N2/C2H2 gas mixture. The morphology, crystalline structure and chemical composition of the coatings were characterized. It was found that the grain size reduce with increasing carbon content, which makes the CrCN coatings refined and smooth. The quasi-one-dimensional carbolite phase was also found in CrN host lattice with C2H2 content ranging from 5% to 20%, and it will be evolved into amorphous carbon and amorphous CNx phases as C2H2 content exceeds 20%. Moreover, we examined the mechanical and tribological properties of the CrCN coatings, and the experimental results confirmed that the friction coefficient of the coatings descend to the lowest value as 0.39 with 30% C2H2 content, due to the graphite (sp2 Csbnd C) phase embed in CrN host lattice; while the chromium carbon (Cr3C2) and diamond (sp3 Csbnd C) phases may give rise to the increase of the coating hardness with the highest value at 23.97 GPa under 20% C2H2 content.

Deposition of Aerosol Particles in Electrically Charged Membrane Filters

Energy Technology Data Exchange (ETDEWEB)

Stroem, L

1972-05-15

A theory for the influence of electric charge on particle deposition on the surface of charged filters has been developed. It has been tested experimentally on ordinary membrane filters and Nuclepore filters of 8 mum pore size, with a bipolar monodisperse test aerosol of 1 mum particle diameter, and at a filter charge up to 20 muC/m2. Agreement with theory was obtained for the Coulomb force between filter and particle for both kinds of filters. The image force between charged filter and neutral particles did not result in the predicted deposition in the ordinary membrane filter, probably due to lacking correspondence between the filter model employed for the theory, and the real filter. For the Nuclepore filter a satisfactory agreement with theory was obtained, also at image interaction

Review of cathodic arc deposition technology at the start of the new millennium

International Nuclear Information System (INIS)

Sanders, D M; Anders, A

2000-01-01

The vacuum cathodic arc has been known to provide a means of producing coatings since the second half of the 19th century. This makes it one of the oldest known means for making coatings in a vacuum. In the last century it has been recognized that the copious quantities of ions produced by the process offers certain advantages in terms of coating properties. Specifically, ions can be steered and/or accelerated toward the parts to be coated. This, in turn, can provide enhanced adhesion, film density, and composition stoichiometry in the case of compound coatings. The ions generated by the cathodic arc have high ''natural'' kinetic energy values in the range 20-200 eV, leading to enhanced surface mobility during the deposition process and even ion subplantation. In many cases, dense coatings are achieved even when non-normal arrival angles are involved. The ion energy can further manipulated by the plasma immersion biasing technique. The issue of macroparticle contamination has been addressed by a variety of novel plasma filters. In spite of all of these advantages, this deposition technique has not been widely adopted in the western nations for commercial coating except in the case of enhancing the performance of cutting tools. The purpose of the this review is to explore reasons for this lack of general use of the technology and to point out some encouraging recent developments which may lead to its accelerated adoption for a much wider variety of applications in the near future

Characterization of SiC in DLC/a-Si films prepared by pulsed filtered cathodic arc using Raman spectroscopy and XPS

International Nuclear Information System (INIS)

Srisang, C.; Asanithi, P.; Siangchaew, K.; Pokaipisit, A.; Limsuwan, P.

2012-01-01

DLC/a-Si films were deposited on germanium substrates. a-Si film was initially deposited as a seed layer on the substrate using DC magnetron sputtering. DLC film was then deposited on the a-Si layer via a pulsed filtered cathodic arc (PFCA) system. In situ ellipsometry was used to monitor the thicknesses of the growth films, allowing a precise control over the a-Si and DLC thicknesses of 6 and 9 nm, respectively. It was found that carbon atoms implanting on a-Si layer act not only as a carbon source for DLC formation, but also as a source for SiC formation. The Raman peak positions at 796 cm -1 and 972 cm -1 corresponded to the LO and TO phonon modes of SiC, respectively, were observed. The results were also confirmed using TEM, XPS binding energy and XPS depth profile analysis.

Thermionic vacuum arc (TVA) technique for magnesium thin film deposition

Energy Technology Data Exchange (ETDEWEB)

Balbag, M.Z., E-mail: zbalbag@ogu.edu.t [Eskisehir Osmangazi University, Education Faculty, Primary Education, Meselik Campus, Eskisehir 26480 (Turkey); Pat, S.; Ozkan, M.; Ekem, N. [Eskisehir Osmangazi University, Art and Science Faculty, Physics Department, Eskisehir 26480 (Turkey); Musa, G. [Ovidius University, Physics Department, Constanta (Romania)

2010-08-15

In this study, magnesium thin films were deposited on glass substrate by the Thermionic Vacuum Arc (TVA) technique for the first time. We present a different technique for deposition of high-quality magnesium thin films. By means of this technique, the production of films is achieved by condensing the plasma of anode material generated using Thermionic Vacuum Arc (TVA) under high vacuum conditions onto the surface to be coated. The crystal orientation and morphology of the deposited films were investigated by using XRD, EDX, SEM and AFM. The aim of this study is to search the use of TVA technique to coat magnesium thin films and to determine some of the physical properties of the films generated. Furthermore, this study will contribute to the scientific studies which search the thin films of magnesium or the compounds containing magnesium. In future, this study will be preliminary work to entirely produce magnesium diboride (MgB{sub 2}) superconductor thin film with the TVA technique.

Phase transitions of doped carbon in CrCN coatings with modified mechanical and tribological properties via filtered cathodic vacuum arc deposition

Energy Technology Data Exchange (ETDEWEB)

Guan, J.J. [Faculty of Materials and Energy, Southwest University, Chongqing 400715 (China); Wang, H.Q. [College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Qin, L.Z., E-mail: qin8394@163.com [Faculty of Materials and Energy, Southwest University, Chongqing 400715 (China); Liao, B.; Liang, H. [College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Li, B. [Faculty of Materials and Energy, Southwest University, Chongqing 400715 (China)

2017-04-15

The CrCN coatings were fabricated onto Si (1 1 1) wafers and SUS304 stainless steel plates using filtered cathodic vacuum arc deposition (FCVAD) technique under different flow ratios of N{sub 2}/C{sub 2}H{sub 2} gas mixture. The morphology, crystalline structure and chemical composition of the coatings were characterized. It was found that the grain size reduce with increasing carbon content, which makes the CrCN coatings refined and smooth. The quasi-one-dimensional carbolite phase was also found in CrN host lattice with C{sub 2}H{sub 2} content ranging from 5% to 20%, and it will be evolved into amorphous carbon and amorphous CN{sub x} phases as C{sub 2}H{sub 2} content exceeds 20%. Moreover, we examined the mechanical and tribological properties of the CrCN coatings, and the experimental results confirmed that the friction coefficient of the coatings descend to the lowest value as 0.39 with 30% C{sub 2}H{sub 2} content, due to the graphite (sp{sup 2} C−C) phase embed in CrN host lattice; while the chromium carbon (Cr{sub 3}C{sub 2}) and diamond (sp{sup 3} C−C) phases may give rise to the increase of the coating hardness with the highest value at 23.97 GPa under 20% C{sub 2}H{sub 2} content.

OES control of a low-pressure DC arc at TiN layer deposition

International Nuclear Information System (INIS)

Andreev, M.A.; Maksimenko, V.N.; Ershov-Pavlov, E.A.

1995-01-01

Results are presented of a low-pressure DC arc study as applied for a deposition of TiN wear-resistant coatings in a commercial plant. Plasma parameters of the arc have been measured by optical emission spectroscopy. The plasma emission spectra have been recorded using a grating spectrometer equipped with an on line computer. Changes in the resulting layers due to a difference in working conditions have been determined by metallography and X-ray analysis giving composition, microstructure and thickness of the resulting layers. Using the data, a correlation between emission spectra of the arc and the TiN layer characteristics has been found. The results allow monitoring parameters of the deposition process to obtain necessary quality of the layer and to increase the process efficiency

Magmatism and Epithermal Gold-Silver Deposits of the Southern Ancestral Cascade Arc, Western Nevada and Eastern California

Science.gov (United States)

John, David A.; du Bray, Edward A.; Henry, Christopher D.; Vikre, Peter

2015-01-01

Many epithermal gold-silver deposits are temporally and spatially associated with late Oligocene to Pliocene magmatism of the southern ancestral Cascade arc in western Nevada and eastern California. These deposits, which include both quartz-adularia (low- and intermediate-sulfidation; Comstock Lode, Tonopah, Bodie) and quartz-alunite (high-sulfidation; Goldfield, Paradise Peak) types, were major producers of gold and silver. Ancestral Cascade arc magmatism preceded that of the modern High Cascades arc and reflects subduction of the Farallon plate beneath North America. Ancestral arc magmatism began about 45 Ma, continued until about 3 Ma, and extended from near the Canada-United States border in Washington southward to about 250 km southeast of Reno, Nevada. The ancestral arc was split into northern and southern segments across an inferred tear in the subducting slab between Mount Shasta and Lassen Peak in northern California. The southern segment extends between 42°N in northern California and 37°N in western Nevada and was active from about 30 to 3 Ma. It is bounded on the east by the northeast edge of the Walker Lane. Ancestral arc volcanism represents an abrupt change in composition and style of magmatism relative to that in central Nevada. Large volume, caldera-forming, silicic ignimbrites associated with the 37 to 19 Ma ignimbrite flareup are dominant in central Nevada, whereas volcanic centers of the ancestral arc in western Nevada consist of andesitic stratovolcanoes and dacitic to rhyolitic lava domes that mostly formed between 25 and 4 Ma. Both ancestral arc and ignimbrite flareup magmatism resulted from rollback of the shallowly dipping slab that began about 45 Ma in northeast Nevada and migrated south-southwest with time. Most southern segment ancestral arc rocks have oxidized, high potassium, calc-alkaline compositions with silica contents ranging continuously from about 55 to 77 wt%. Most lavas are porphyritic and contain coarse plagioclase �

Hypergravity synthesis of graphitic carbon nanomaterial in glide arc plasma

NARCIS (Netherlands)

Šperka, J.; Soucek, P.; van Loon, J.J.W.A.; Dowson, A.; Schwarz, C.; Krause, J.; Butenko, Y.; Kroesen, G.; Kudrle, V.

2014-01-01

A nanostructured carbon material was synthesized using a methane/helium glide arc plasma under standard and increased gravity. Material analysis performed on samples collected from an effluent gas filter showed that the deposited material was present in the form of carbon nanoparticles. They

Directly-deposited blocking filters for high-performance silicon x-ray detectors

Science.gov (United States)

Bautz, M.; Kissel, S.; Masterson, R.; Ryu, K.; Suntharalingam, V.

2016-07-01

Silicon X-ray detectors often require blocking filters to mitigate noise and out-of-band signal from UV and visible backgrounds. Such filters must be thin to minimize X-ray absorption, so direct deposition of filter material on the detector entrance surface is an attractive approach to fabrication of robust filters. On the other hand, the soft (E OD 6) care must be taken to prevent light from entering the sides and mounting surfaces of the detector. Our methods have been used to deposit filters on the detectors of the REXIS instrument scheduled to fly on OSIRIS-ReX later this year.

Hydrothermal manganese oxide deposits from the Izu-Ogasawara (Bonin)-Mariana Arc and adjacent areas

Energy Technology Data Exchange (ETDEWEB)

Usui, A.; Nishimura, A. (Geological Survey of Japan, Tsukuba (Japan))

1992-04-27

Modern and fossil hydrothermal manganese oxide deposits were discovered from a number of locations in the Izu-Ogasawara(Bonin)-Mariana Arc and adjacent areas during the Hakurei-Maru cruises from 1984 to 1989. This paper describes the occurrence and characteristics of these manganese deposits and their geological significance. It was found that the mineralogical and chemical composition and microstructure of the deposits are typically different from manganese nodules and crusts of hydrogenetic or diagenetic origin. Hardpans, veinlets, sheets, and irregular mass of the hydrothermal manganese deposits often cover a large area of sea bed, which suggests possible high-temperature hydrothermal sulfide deposits in their vicinity. On the other hand, the manganese minerals sometimes occur as substrate of younger hydrogenetic crusts and as nucleus of hydrogenetic nodules, which can provide a geological history of low-temperature hydrothermal activity on the past island arcs. 45 refs., 19 figs., 3 tabs.

A high-current pulsed cathodic vacuum arc plasma source

International Nuclear Information System (INIS)

Oates, T.W.H.; Pigott, J.; Mckenzie, D.R.; Bilek, M.M.M.

2003-01-01

Cathodic vacuum arcs (CVAs) are well established as a method for producing metal plasmas for thin film deposition and as a source of metal ions. Fundamental differences exist between direct current (dc) and pulsed CVAs. We present here results of our investigations into the design and construction of a high-current center-triggered pulsed CVA. Power supply design based on electrolytic capacitors is discussed and optimized based on obtaining the most effective utilization of the cathode material. Anode configuration is also discussed with respect to the optimization of the electron collection capability. Type I and II cathode spots are observed and discussed with respect to cathode surface contamination. An unfiltered deposition rate of 1.7 nm per pulse, at a distance of 100 mm from the source, has been demonstrated. Instantaneous plasma densities in excess of 1x10 19 m -3 are observed after magnetic filtering. Time averaged densities an order of magnitude greater than common dc arc densities have been demonstrated, limited by pulse repetition rate and filter efficiency

Structure of MoCN films deposited by cathodic arc evaporation

Energy Technology Data Exchange (ETDEWEB)

Gilewicz, A., E-mail: adam.gilewicz@tu.koszalin.pl [Koszalin University of Technology, Faculty of Technology and Education, Sniadeckich 2, 75-453 Koszalin (Poland); Jedrzejewski, R.; Kochmanska, A.E. [West Pomeranian University of Technology Szczecin, Faculty of Mechanical Engineering and Mechatronics, 19 Piastów Ave., 70-313 Szczecin (Poland); Warcholinski, B. [Koszalin University of Technology, Faculty of Technology and Education, Sniadeckich 2, 75-453 Koszalin (Poland)

2015-02-27

Molybdenum carbonitride (MoCN) coatings were deposited onto HS6-5-2 steel substrate using pure Mo targets in mixed acetylene and nitrogen atmosphere by cathodic arc evaporation. The structural properties of MoCN coatings with different carbon contents (as an effect of the C{sub 2}H{sub 2} flow rate) were investigated systematically. Phase and chemical composition evolution of the coatings were characterized both by the glancing angle of X-ray diffraction (XRD) and wavelength dispersive spectrometry, respectively. These analyses have been supplemented by estimates of grain sizes and stress in the coatings. The XRD results show that the increase in acetylene flow rate causes the formation of molybdenum carbide (MoC) hexagonal phase in the coatings, a reduction of grain size and an increase in internal stress. - Highlights: • MoN and MoCN coatings were deposited by cathodic arc evaporation in nitrogen atmosphere. • MoCN coatings were formed using different acetylene flow rates. • Phase composition evolution was observed. • Crystallite size and stress were calculated.

Superhard nanocomposite nc-TiC/a-C:H film fabricated by filtered cathodic vacuum arc technique

International Nuclear Information System (INIS)

Wang Yaohui; Zhang Xu; Wu Xianying; Zhang Huixing; Zhang Xiaoji

2008-01-01

Superhard nanocomposite nc-TiC/a-C:H films, with an excellent combination of high elastic recovery, low friction coefficient and good H/E ratio, were prepared by filtered cathodic vacuum arc technique using the C 2 H 2 gas as the precursor. The effect of C 2 H 2 flow rate on the microstructure, phase composition, mechanical and tribological properties of nanocomposite nc-TiC/a-C:H films have been investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy disperse spectroscopy (EDS), microindentation and tribotester measurements. It was observed that the C 2 H 2 flow rate significantly affected the Ti content and hardness of films. Furthermore, by selecting the proper value for C 2 H 2 flow rate, 20 sccm, one can deposit the nanocomposite film nc-TiC/a-C:H with excellent properties such as superhardness (66.4 GPa), high elastic recovery (83.3%) and high H/E ratio (0.13)

Dynamics of particle loading in deep-bed filter. Transport, deposition and reentrainment

Directory of Open Access Journals (Sweden)

Przekop Rafał

2016-09-01

Full Text Available Deep bed filtration is an effective method of submicron and micron particle removal from the fluid stream. There is an extensive body of literature regarding particle deposition in filters, often using the classical continuum approach. However, the approach is not convenient for studying the influence of particle deposition on filter performance (filtration efficiency, pressure drop when non-steady state boundary conditions have to be introduced. For the purposes of this work the lattice-Boltzmann model describes fluid dynamics, while the solid particle motion is modeled by the Brownian dynamics. For aggregates the effect of their structure on displacement is taken into account. The possibility of particles rebound from the surface of collector or reentrainment of deposits to fluid stream is calculated by energy balanced oscillatory model derived from adhesion theory. The results show the evolution of filtration efficiency and pressure drop of filters with different internal structure described by the size of pores. The size of resuspended aggregates and volume distribution of deposits in filter were also analyzed. The model enables prediction of dynamic filter behavior. It can be a very useful tool for designing filter structures which optimize maximum lifetime with the acceptable values of filtration efficiency and pressure drop.

Achieving high mobility ZnO : Al at very high growth rates by dc filtered cathodic arc deposition

International Nuclear Information System (INIS)

Mendelsberg, R J; Lim, S H N; Wallig, J; Anders, A; Zhu, Y K; Milliron, D J

2011-01-01

Achieving a high growth rate is paramount for making large-area transparent conducting oxide coatings at a low cost. Unfortunately, the quality of thin films grown by most techniques degrades as the growth rate increases. Filtered dc cathodic arc is a lesser known technique which produces a stream of highly ionized plasma, in stark contrast to the neutral atoms produced by standard sputter sources. Ions bring a large amount of potential energy to the growing surface which is in the form of heat, not momentum. By minimizing the distance from cathode to substrate, the high ion flux gives a very high effective growth temperature near the film surface without causing damage from bombardment. The high surface temperature is a direct consequence of the high growth rate and allows for high-quality crystal growth. Using this technique, 500-1300 nm thick and highly transparent ZnO : Al films were grown on glass at rates exceeding 250 nm min -1 while maintaining resistivity below 5 x 10 -4 Ω cm with electron mobility as high as 60 cm 2 V -1 s -1 . (fast track communication)

Arc-discharge and magnetron sputtering combined equipment for nanocomposite coating deposition

International Nuclear Information System (INIS)

Koval, N.N.; Borisov, D.P.; Savostikov, V.M.

2005-01-01

It is known that characteristics of nanocomposite coatings produced by reactive magnetron sputtering undergo an essential influence on the following parameters such as original component composition of targets being sputtered, as well as abundance ratio of such components in the coatings deposited, relative content of inert and reactionary gases in a gas mixture used and a value of operating pressure in a chamber, substrate temperature, and a value of substrate bias potential, determining energy of ionized atoms, ionized atoms flow density, i.e. ion current density on a substrate. The multifactor character of production process of nanocomposite coatings with certain physical and mechanical properties demands a purposeful and complex control on all above-mentioned parameters. To solve such a problem, an arc-discharge and magnetron sputtering combined equipment including a vacuum chamber of approximately ∼ 0.5 m 3 with a built-in low-pressure plasma generator made on the basis of non-self-sustained discharge with a thermal cathode and a planar magnetron combined with two sputtered targets has been created. Construction of such a complex set-up provides both an autonomous mode of operation and simultaneous operation of an arc plasma generator and magnetron sputtering system. Magnetron sputtering of either one or two targets simultaneously is provided as well. An arc plasma generator enables ions current density control on a substrate in a wide range due to discharge current varying from 1 to 100 A. Energy of ions is also being controlled in a wide range by a negative bias potential from 0 to 1000 V applied to a substrate. The wide control range of gas plasma density of a arc discharge of approximately 10 9 -10 11 cm -3 and high uniformity of its distribution over the total volume of an operating chamber (about 15% error with regard to the mean value) provides a purposeful and simultaneous control either of magnetron discharge characteristics (operating pressure of

Protective coating of inner surface of steel tubes via vacuum arc deposition

Energy Technology Data Exchange (ETDEWEB)

Maile, K.; Roos, E.; Lyutovich, A.; Boese, J.; Itskov, M. [Stuttgart Univ. (DE). Materialpruefungsanstalt (MPA); Ashurov, Kh.; Mirkarimov, A.; Kazantsev, S.; Kadirov, Kh. [Uzbek Academy of Science, Tashkent (Uzbekistan). Arifov Inst. of Electronics

2010-07-01

The Vacuum Arc Deposition (VAD) technique based on sputtering a chosen electrode material and its deposition via plasma allows highly-productive technology for creating a wide class of protecting coatings on complex structures. In this work, VAD was applied as a method for the protection of the inner surface of tubes for power-plant boilers against steam oxidation. For this aim, a source cathode of an alloy with high chromium and nickel content was employed in two different VAD treatment systems: a horizontal vacuum chamber (MPA) and a vertical system where the work-piece of the tubes to be protected served as a vacuum changer (Arifov Institute of Electronics). Surface coating with variation of deposition parameters and layer thickness was performed. Characterisation of coated tubes has shown that the method realised in this work allows attainment of material transfer from the cathode to the inner surface with nearly equal chemical composition. It was demonstrated that the initial martensitic structure of the tubes was kept after the vacuum-arc treatment which can provide for both the high mechanical robustness and the corrosion-resistance of the final material. (orig.)

Amorphous boron coatings produced with vacuum arc deposition technology

CERN Document Server

Klepper, C C; Yadlowsky, E J; Carlson, E P; Keitz, M D; Williams, J M; Zuhr, R A; Poker, D B

2002-01-01

In principle, boron (B) as a material has many excellent surface properties, including corrosion resistance, very high hardness, refractory properties, and a strong tendency to bond with most substrates. The potential technological benefits of the material have not been realized, because it is difficult to deposit it as coatings. B is difficult to evaporate, does not sputter well, and cannot be thermally sprayed. In this article, first successful deposition results from a robust system, based on the vacuum (cathodic) arc technology, are reported. Adherent coatings have been produced on 1100 Al, CP-Ti, Ti-6Al-4V, 316 SS, hard chrome plate, and 52 100 steel. Composition and thickness analyses have been performed by Rutherford backscattering spectroscopy. Hardness (H) and modules (E) have been evaluated by nanoindentation. The coatings are very pure and have properties characteristic of B suboxides. A microhardness of up to 27 GPa has been measured on a 400-nm-thick film deposited on 52 100 steel, with a corresp...

Deposition of titanium nitride layers by electric arc – Reactive plasma spraying method

International Nuclear Information System (INIS)

Şerban, Viorel-Aurel; Roşu, Radu Alexandru; Bucur, Alexandra Ioana; Pascu, Doru Romulus

2013-01-01

Highlights: ► Titanium nitride layers deposited by electric arc – reactive plasma spraying method. ► Deposition of titanium nitride layers on C45 steel at different spraying distances. ► Characterization of the coatings hardness as function of the spraying distances. ► Determination of the corrosion behavior of titanium nitride layers obtained. - Abstract: Titanium nitride (TiN) is a ceramic material which possesses high mechanical properties, being often used in order to cover cutting tools, thus increasing their lifetime, and also for covering components which are working in corrosive environments. The paper presents the experimental results on deposition of titanium nitride coatings by a new combined method (reactive plasma spraying and electric arc thermal spraying). In this way the advantages of each method in part are combined, obtaining improved quality coatings in the same time achieving high productivity. Commercially pure titanium wire and C45 steel as substrate were used for experiments. X-ray diffraction analysis shows that the deposited coatings are composed of titanium nitride (TiN, Ti 2 N) and small amounts of Ti 3 O. The microstructure of the deposited layers, investigated both by optical and scanning electron microscopy, shows that the coatings are dense, compact, without cracks and with low porosity. Vickers microhardness of the coatings presents maximum values of 912 HV0.1. The corrosion tests in 3%NaCl solution show that the deposited layers have a high corrosion resistance compared to unalloyed steel substrate.

Two-dimensional modelling of internal arc effects in an enclosed MV cell provided with a protection porous filter

International Nuclear Information System (INIS)

Rochette, D; Clain, S; Andre, P; Bussiere, W; Gentils, F

2007-01-01

Medium voltage (MV) cells have to respect standards (for example IEC ones (IEC TC 17C 2003 IEC 62271-200 High Voltage Switchgear and Controlgear-Part 200 1st edn)) that define security levels against internal arc faults such as an accidental electrical arc occurring in the apparatus. New protection filters based on porous materials are developed to provide better energy absorption properties and a higher protection level for people. To study the filter behaviour during a major electrical accident, a two-dimensional model is proposed. The main point is the use of a dedicated numerical scheme for a non-conservative hyperbolic problem. We present a numerical simulation of the process during the first 0.2 s when the safety valve bursts and we compare the numerical results with tests carried out in a high power test laboratory on real electrical apparatus

Two-dimensional modelling of internal arc effects in an enclosed MV cell provided with a protection porous filter

Science.gov (United States)

Rochette, D.; Clain, S.; André, P.; Bussière, W.; Gentils, F.

2007-05-01

Medium voltage (MV) cells have to respect standards (for example IEC ones (IEC TC 17C 2003 IEC 62271-200 High Voltage Switchgear and Controlgear—Part 200 1st edn)) that define security levels against internal arc faults such as an accidental electrical arc occurring in the apparatus. New protection filters based on porous materials are developed to provide better energy absorption properties and a higher protection level for people. To study the filter behaviour during a major electrical accident, a two-dimensional model is proposed. The main point is the use of a dedicated numerical scheme for a non-conservative hyperbolic problem. We present a numerical simulation of the process during the first 0.2 s when the safety valve bursts and we compare the numerical results with tests carried out in a high power test laboratory on real electrical apparatus.

Two-dimensional modelling of internal arc effects in an enclosed MV cell provided with a protection porous filter

Energy Technology Data Exchange (ETDEWEB)

Rochette, D [Laboratoire Arc Electrique et Plasmas Thermiques, CNRS UMR 6069, Universite Blaise Pascal, IUT de Montlucon, Avenue Aristide Briand, BP 2235, 03101 Montlucon Cedex (France); Clain, S [Laboratoire de Mathematiques pour l' Industrie et la Physique, CNRS UMR 5640, Universite Paul Sabatier Toulouse 3, 118 route de Narbonne, 31062 Toulouse Cedex 4 (France); Andre, P [Laboratoire Arc Electrique et Plasmas Thermiques, CNRS UMR 6069, Universite Blaise Pascal, IUT de Montlucon, Avenue Aristide Briand, BP 2235, 03101 Montlucon Cedex (France); Bussiere, W [Laboratoire Arc Electrique et Plasmas Thermiques, CNRS UMR 6069, Universite Blaise Pascal, IUT de Montlucon, Avenue Aristide Briand, BP 2235, 03101 Montlucon Cedex (France); Gentils, F [Schneider Electric-Science and Technology Division-Research Center A2, 38050 Grenoble Cedex 9 (France)

2007-05-21

Medium voltage (MV) cells have to respect standards (for example IEC ones (IEC TC 17C 2003 IEC 62271-200 High Voltage Switchgear and Controlgear-Part 200 1st edn)) that define security levels against internal arc faults such as an accidental electrical arc occurring in the apparatus. New protection filters based on porous materials are developed to provide better energy absorption properties and a higher protection level for people. To study the filter behaviour during a major electrical accident, a two-dimensional model is proposed. The main point is the use of a dedicated numerical scheme for a non-conservative hyperbolic problem. We present a numerical simulation of the process during the first 0.2 s when the safety valve bursts and we compare the numerical results with tests carried out in a high power test laboratory on real electrical apparatus.

Nitrogen doping for adhesion improvement of DLC film deposited on Si substrate by Filtered Cathodic Vacuum Arc (FCVA) technique

Energy Technology Data Exchange (ETDEWEB)

Bootkul, D., E-mail: mo_duangkhae@hotmail.com [Department of General Science, Faculty of Science, Srinakharinwirot University, Bangkok 10110 (Thailand); Supsermpol, B.; Saenphinit, N. [Western Digital Company, Ayutthaya 13160 (Thailand); Aramwit, C. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50202 (Thailand); Intarasiri, S., E-mail: saweat@gmail.com [Science and Technology Research Institute, Chiang Mai University, Chiang Mai 50202 (Thailand)

2014-08-15

Diamond-like carbon (DLC) films have been used in many applications due to their attractive combination of properties including chemical inertness, corrosion protection, biocompatibility, high hardness, and low wear rates. However, they still have some limitations such as high internal stresses and low toughness which lead to poor adhesion of films. Synthesis of nitrogen-doped DLC (N-DLC) offers the possibility of overcoming these limitations. In this study, DLC films, namely tetrahedral amorphous carbon (ta-C) and nitrogen doped tetrahedral amorphous carbon (ta-C:N) were deposited on single crystalline Si wafer substrates using the Filtered Cathodic Vacuum Arc (FCVA) technique. Film characterizations were carried out by Raman spectroscopy, atomic force microscopy (AFM), scanning electron microscopy (SEM), triboindenter tester and nano-scratch tester. Measurement results showed that intentionally doping with nitrogen reduced the carbon sp{sup 3} content and increased the surface roughness in comparison with that of pure ta-C films. The hardness measurement confirmed the Raman and AFM analyses that adding nitrogen in ta-C films decreased the hardness, especially with high nitrogen content. However, the nano-scratch test revealed the increasing of the critical load with nitrogen. This work, then, extended its scope to investigate the properties of double-layer ta-C films which were composed of ta-C:N interlayer of various thickness around 10–30 nm and ta-C top-layer with thickness of around 80 nm. Microstructure characterization demonstrated that a ta-C:N interlayer gradually decreased the sp{sup 3} fraction in the films and increased film roughness whenever the ta-C:N interlayer thickness increased. In this structure, the tribological property in terms of adhesion to the Si substrate was significantly improved by about 20–90%, but the mechanical property in terms of hardness was gradually degraded by about 2–10%, compared to pure ta-C film, when the ta

The Chahnaly low sulfidation epithermal gold deposit, western Makran volcanic arc, southeastern Iran

Science.gov (United States)

Sholeh, Ali; Rastad, Ebrahim; Huston, David L.; Gemmell, J. Bruce; Taylor, Ryan D.

2016-01-01

The Chahnaly low-sulfidation epithermal Au deposit and nearby Au prospects are located northwest of the intermittently active Bazman stratovolcano on the western end of the Makran volcanic arc, which formed as the result of subduction of the remnant Neo-Tethyan oceanic crust beneath the Lut block. The arc hosts the Siah Jangal epithermal and Kharestan porphyry prospects, near Taftan volcano, as well as the Saindak Cu-Au porphyry deposit and world-class Reko Diq Cu-Au porphyry deposit, near Koh-i-Sultan volcano to the east-northeast in Pakistan. The host rocks for the Chahnaly deposit include early Miocene andesite and andesitic volcaniclastic rocks that are intruded by younger dacitic domes. Unaltered late Miocene dacitic ignimbrites overlie these rocks. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) U-Pb zircon geochronology data yield ages between 21.8 and 9.9 Ma for the acidic-intermediate regional volcanism. The most recent volcanic activity of the Bazman stratovolcano involved extrusion of an olivine basalt during Pliocene to Quaternary times. Interpretation of geochemical data indicate that the volcanic rocks are synsubduction and calc-alkaline to subalkaline. The lack of a significant negative Eu anomaly, a listric-shaped rare earth element pattern, and moderate La/Yb ratios of host suites indicate a high water content of the source magma.

Deposition of thin layers of boron nitrides and hydrogenated microcrystalline silicon assisted by high current direct current arc plasma; Deposition assistee par un plasma a arc a haut courant continu de couches minces de Nitrure de Bore et de Silicium microcristallin hydrogene

Energy Technology Data Exchange (ETDEWEB)

Franz, D. [Ecole Polytechnique Federale de Lausanne, Centre de Recherches en Physique des Plasmas (CRPP), CH-1015 Lausanne (Switzerland)

1999-09-01

In the frame of this thesis, a high current direct current arc (HCDCA) used for the industrial deposition of diamond, has been adapted to study the deposition of two types of coatings: a) boron nitride, whose cubic phase is similar to diamond, for tribological applications, b) hydrogenated microcrystalline silicon, for applications in the semiconductor fields (flat panel displays, solar cells,...). For the deposition of these coatings, the substrates were placed in the diffusion region of the arc. The substrate heating is mainly due to atomic species recombining on its surface. The deposition temperature, varying from 300 to 900 {sup o}C according to the films deposited, is determined by the substrate position, the arc power and the injected gas fluxes, without the use of any external heating or cooling system. Measurements performed on the arc plasma show that the electronic temperature is around 2 eV (23'000 K) while the gas temperature is lower than 5500 K. Typical electronic densities are in the range of 10{sup 12}-10{sup 1'}3 cm{sup -3}. For the deposition of boron nitride films, different boron precursors were used and a wide parameter range was investigated. The extreme difficulty of synthesising cubic boron nitride films by chemical vapour deposition (CVD) did not allow to stabilize the cubic phase of boron nitride in HCDCA. Coatings resulted in hexagonal or amorphous boron nitride with a chemical composition close to stoichiometric. The presence of hydrogen leads to the deposition of rough and porous films. Negative biasing of the samples, for positive ion bombardment, is commonly used to stabilize the cubic phase. In HCDCA and in our biasing range, only a densification of the films could be observed. A boron nitride deposition plasma study by infrared absorption spectroscopy in a capacitive radio frequency reactor has demonstrated the usefulness of this diagnostic for the understanding of the various chemical reactions which occur in this kind

Thick CrN/NbN multilayer coating deposited by cathodic arc technique

Energy Technology Data Exchange (ETDEWEB)

Araujo, Juliano Avelar; Tschiptschin, Andre Paulo; Souza, Roberto Martins, E-mail: antschip@usp.br [Universidade de Sao Paulo (USP), SP (Brazil); Lima, Nelson Batista de [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2017-01-15

The production of tribological nanoscale multilayer CrN/NbN coatings up to 6 μm thick by Sputtering/HIPIMS has been reported in literature. However, high demanding applications, such as internal combustion engine parts, need thicker coatings (>30 μm). The production of such parts by sputtering would be economically restrictive due to low deposition rates. In this work, nanoscale multilayer CrN/NbN coatings were produced in a high-deposition rate, industrial-size, Cathodic Arc Physical Vapor Deposition (ARC-PVD) chamber, containing three cathodes in alternate positions (Cr/ Nb/Cr). Four 30 μm thick NbN/CrN multilayer coatings with different periodicities (20, 10, 7.5 and 4 nm) were produced. The coatings were characterized by X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). The multilayer coating system was composed of alternate cubic rock salt CrN and NbN layers, coherently strained due to lattice mismatch. The film grew with columnar morphology through the entire stratified structure. The periodicities adopted were maintained throughout the entire coating. The 20 nm periodicity coating showed separate NbN and CrN peaks in the XRD patterns, while for the lower periodicity (≤10nm) coatings, just one intermediate lattice (d-spacing) was detected. An almost linear increase of hardness with decreasing bilayer period indicates that interfacial effects can dominate the hardening mechanisms. (author)

Effect of duct bias on transport of vacuum arc plasmas through curved magnetic filters

International Nuclear Information System (INIS)

Anders, A.; Anders, S.; Brown, I.G.

1994-01-01

The plasma output of a 90 degree magnetic macroparticle filter of vacuum arc plasma was monitored by a Langmuir probe as a function of bias of the duct wall and guiding magnetic field. Maximum plasma transport through the filter was found at a positive bias of about 20 V. A relatively small magnetic field of 10--30 mT is sufficient for effective guiding of the plasma, and further increase of the guiding field improves the filter efficiency only gradually. The potential of a floating duct changes from negative to positive when the guiding field is increased. This can be explained by the balance of electron and ion flux transverse to the magnetic field. Saturation in the plasma output at high guiding field (>120 mT) is observed for carbon but not for heavy elements. The transport of plasma through bent ducts is made possible by the magnetic pressure of the guiding field, and by sheath and space-charge electric fields

Influence of deposition rate on the properties of tin coatings deposited on tool steels using arc method

International Nuclear Information System (INIS)

Akhtar, P.; Abbas, M.

2007-01-01

Titanium nitride (TiN) widely used as hard coating material, was coated on tool steels, namely on high-speed steel (HSS) and D2 tool steel by physical vapour deposition method. The study concentrated on cathodic arc physical vapour deposition (CAPVD), a technique used for the deposition of hard coatings for tooling applications, and which has many advantages. The main drawback of this technique, however, is the formation of macrodroplets (MD's) during deposition, resulting in films with rougher morphology. Various standard characterization techniques and equipment, such as electron microscopy, atomic force microscopy, hardness testing machine, scratch tester and pin-on-disc machine, were used to analyze and quantify the following properties and parameters, surface morphology, thickness, hardness, adhesion and coefficient of friction (COF) of the deposited coatings. Surface morphology revealed that the MD's produced during the etching stage, protruded through the thin film, resulting in film with deteriorated surface features. Both coating thickness and indentation loads influenced the hardness of the deposited coatings. The coatings deposited on HSS exhibit better adhesion compared to those on D2 tool steel. Standard deviation indicates that the coating deposited with thickness around 6.7 macro m showed the most stable trend of COF versus sliding distance. (author)

Device quality ZnO grown using a Filtered Cathodic Vacuum Arc

International Nuclear Information System (INIS)

Elzwawi, Salim; Kim, Hyung Suk; Heinhold, Robert; Lynam, Max; Turner, Gary; Partridge, Jim G.; McCulloch, Dougal G.

2012-01-01

In this paper we report on the structural, electrical and optical characteristics of unintentionally doped ZnO films grown on a-plane sapphire substrates using the Filtered Cathodic Vacuum Arc (FCVA) technique. The resulting films showed considerable promise for device applications with properties including high transparency, moderate intrinsic carrier concentrations (10 17 -10 19 cm -3 ), electron mobilities up to 30 cm 2 /Vs, low surface roughness (typically <2% of film thickness) and well-structured photoluminescence. Post-annealing in oxygen at temperatures up to 800 °C produced significant improvements in the properties of these films. Silver oxide Schottky diodes fabricated on FCVA ZnO showed ideality factors as low as 1.20 and good sensitivity to ultraviolet light.

Synthesis of aluminum nitride films by plasma immersion ion implantation-deposition using hybrid gas-metal cathodic arc gun

International Nuclear Information System (INIS)

Shen Liru; Fu, Ricky K.Y.; Chu, Paul K.

2004-01-01

Aluminum nitride (AlN) is of interest in the industry because of its excellent electronic, optical, acoustic, thermal, and mechanical properties. In this work, aluminum nitride films are deposited on silicon wafers (100) by metal plasma immersion ion implantation and deposition (PIIID) using a modified hybrid gas-metal cathodic arc plasma source and with no intentional heating to the substrate. The mixed metal and gaseous plasma is generated by feeding the gas into the arc discharge region. The deposition rate is found to mainly depend on the Al ion flux from the cathodic arc source and is only slightly affected by the N 2 flow rate. The AlN films fabricated by this method exhibit a cubic crystalline microstructure with stable and low internal stress. The surface of the AlN films is quite smooth with the surface roughness on the order of 1/2 nm as determined by atomic force microscopy, homogeneous, and continuous, and the dense granular microstructures give rise to good adhesion with the substrate. The N to Al ratio increases with the bias voltage applied to the substrates. A fairly large amount of O originating from the residual vacuum is found in the samples with low N:Al ratios, but a high bias reduces the oxygen concentration. The compositions, microstructures and crystal states of the deposited films are quite stable and remain unchanged after annealing at 800 deg. C for 1 h. Our hybrid gas-metal source cathodic arc source delivers better AlN thin films than conventional PIIID employing dual plasmas

Shielding and filtering techniques to protect sensitive instrumentation from electromagnetic interference caused by arc welding

International Nuclear Information System (INIS)

Kalechstein, W.

1997-01-01

Electromagnetic interference (EMI) caused by arc welding is a concern for sensitive CANDU instrumentation and control equipment, especially start-up instrumentation (SUI) and ion chamber instruments used to measure neutron flux at low power. Measurements of the effectiveness of simple shielding and filtering techniques that may be applied to limit arc welding electromagnetic emissions below the interference threshold are described. Shielding configurations investigated include an arrangement in which the welding power supply, torch (electrode holder), interconnecting cables and welder operator were housed in a single enclosure and a more practical configuration of separate shields for the power supply, cables and operator with torch. The two configuration were found to provide 30 dB and 26 dB attenuation, respectively, for arc welder electric-field emissions and were successful in preventing EMI in SUI set up just outside the shielding enclosures. Practical improvements that may be incorporated in the shielding arrangement to facilitate quick setup in the field in a variety of application environments, while maintaining adequate EMI protection, are discussed. (author)

Phase formation and microstructure evolution of arc ion deposited Cr2AlC coating after heat treatment

International Nuclear Information System (INIS)

Li, J.J.; Qian, Y.H.; Niu, D.; Zhang, M.M.; Liu, Z.M.; Li, M.S.

2012-01-01

Highlights: ► Cr 2 AlC coating was prepared by arc ion plating combined with post annealing. ► The coating deposited by arc ion plating without heating was amorphous. ► Amorphous coating transformed to crystalline Cr 2 AlC after annealing at 620 °C in Ar. - Abstract: Due to the excellent oxidation and hot corrosion resistance and matched thermal expansion coefficient to normal alloys, Cr 2 AlC has potential applications as high-temperature protective coating. In the present work, the preparation of Cr 2 AlC coating has been achieved through cathodic arc deposition method combined with heat post-treatment. It was found that the coating, deposited from Cr 2 AlC compound target in the unintentional heating condition, was amorphous. After annealing at 620 °C in Ar for 20 h, the amorphous Cr–Al–C coating happened to crystallize and transformed to crystalline Cr 2 AlC as the major phase. It is obvious that the formation temperature of Cr 2 AlC was decreased from about 1050 °C for sintered bulk to around 620 °C for the as-deposited coating, resulting from the homogeneous mixture of the Cr, Al and C at atomic level in the Cr–Al–C coating. Apart from crystalline Cr 2 AlC, the annealed coating also contained AlCr 2 and little Cr 7 C 3 . AlCr 2 formed due to the loss of C during deposition, and little Cr 7 C 3 always existed in the sintered Cr 2 AlC compound target as impurity phase.

Deposition of indium tin oxide thin films by cathodic arc ion plating

International Nuclear Information System (INIS)

Yang, M.-H.; Wen, J.-C.; Chen, K.-L.; Chen, S.-Y.; Leu, M.-S.

2005-01-01

Indium tin oxide (ITO) thin films have been deposited by cathodic arc ion plating (CAIP) using sintered oxide target as the source material. In an oxygen atmosphere of 200 deg. C, ITO films with a lowest resistivity of 2.2x10 -4 Ω-cm were obtained at a deposition rate higher than 450 nm/min. The carrier mobility of ITO shows a maximum at some medium pressures. Although morphologically ITO films with a very fine nanometer-sized structure were observed to possess the lowest resistivity, more detailed analyses based on X-ray diffraction are attempted to gain more insight into the factors that govern electron mobility in this investigation

Filter construction technology in mining drilling hole for in-situ leaching of multilayer deposit

International Nuclear Information System (INIS)

Jiang Yan; Hu Baishi; Tan Yahui; Yang Lizhi; Li Xiaojian; Wang Xiaodong; Chang Jingtao; Qin Hao

2014-01-01

Taking a typical multilayer sandstone uranium deposit as example, study was carried out on filter construction technology in mining drilling hole for in-situ leaching of multilayer deposit. According to the character of multilayer sandstone, four injecting holes and one drawning hole were designed between the P13-P15 exploration lines, five different methods were used to construct filter. Construction technology by different methods was introduced and the advantages and disadvantages of the construction filter with five methods were analysed. As far as five experimental drilling holes, layered gravel-filling hole construction technology is a suitable method for construction multilayer filter with continuous construction, simple operation and good effect of well completion. (authors)

On the properties of nanocomposite amorphous carbon films prepared by off-plane double bend filtered cathodic vacuum arc

International Nuclear Information System (INIS)

Tay, B.K.; Zhang, P.

2002-01-01

It is known to deposit hard thin films, such as tetrahedral amorphous carbon (ta-C), using a filtered cathode vacuum arc (FCVA). These ta-C films have interesting and useful properties because of the high sp 3 fraction of carbon atoms (up to 87%) in the film. However, the high internal stress in the films can limit their applications as the film may flake away from the substrate. In order to reduce the internal stress of the ta-C films and in an attempt to improve adhesion of thick films of this type, growth modifications such as incorporating metal into the ta-C films have been carried out. Nanocomposite amorphous carbon films were deposited by FCVA technique using metal-carbon composite target. Atomic force microscopy, Raman, and X-ray photoelectron spectroscopy were used to characterize the morphology and structure of the films. Nanoindenter and surface profilometer were used to determine the hardness, Young's modulus, and internal stress. The same metal composition targets for different elements results in different metal composition in the corresponding nanocomposite amorphous carbon films. We attribute this observation to the dynamic balance deposition effect of the FCVA deposition process. The influence of the type of metallic elements and its composition in the films on the structural, mechanical properties, surface energy and field emission (FE) performance was studied. The incorporation of metal into the films results in the decrease of sp 3 fraction, internal stress in the films, but the hardness and Young's modulus remains at high level. The surface energy of the films increases with incorporating Ni atoms, but decreases after incorporating Fe and Al atoms into the films. After heat-treatment, the incorporation of metal into ta-C films can greatly improve the FE performance

High rate deposition of transparent conducting oxide thin films by vacuum arc plasma evaporation

International Nuclear Information System (INIS)

Minami, Tadatsugu; Ida, Satoshi; Miyata, Toshihiro

2002-01-01

Transparent conducting oxide (TCO) thin films have been deposited at a high rate above 370 nm/min by vacuum arc plasma evaporation (VAPE) using sintered oxide fragments as the source material. It was found that the deposition rate of TCO films was strongly dependent on the deposition pressure, whereas the obtained electrical properties were relatively independent of the pressure. Resistivities of 5.6x10 -4 and 2.3x10 -4 Ω·cm and an average transmittance above 80% (with substrate included) in the visible range were obtained in Ga-doped ZnO (GZO) thin films deposited at 100 and 350 deg. C, respectively. In addition, a resistivity as low as 1.4x10 -4 Ω·cm and an average transmittance above 80% were also obtained in indium-tin-oxide (ITO) films deposited at 300 deg. C. The deposited TCO films exhibited uniform distributions of resistivity and thickness on large area substrates

High rate deposition of transparent conducting oxide thin films by vacuum arc plasma evaporation

Energy Technology Data Exchange (ETDEWEB)

Minami, Tadatsugu; Ida, Satoshi; Miyata, Toshihiro

2002-09-02

Transparent conducting oxide (TCO) thin films have been deposited at a high rate above 370 nm/min by vacuum arc plasma evaporation (VAPE) using sintered oxide fragments as the source material. It was found that the deposition rate of TCO films was strongly dependent on the deposition pressure, whereas the obtained electrical properties were relatively independent of the pressure. Resistivities of 5.6x10{sup -4} and 2.3x10{sup -4} {omega}{center_dot}cm and an average transmittance above 80% (with substrate included) in the visible range were obtained in Ga-doped ZnO (GZO) thin films deposited at 100 and 350 deg. C, respectively. In addition, a resistivity as low as 1.4x10{sup -4} {omega}{center_dot}cm and an average transmittance above 80% were also obtained in indium-tin-oxide (ITO) films deposited at 300 deg. C. The deposited TCO films exhibited uniform distributions of resistivity and thickness on large area substrates.

Early Depositional History of the Eocene Izu-Bonin Mariana Arc, Western Pacific Ocean

Science.gov (United States)

Waldman, R.; Marsaglia, K. M.; Tepley, F. J., III

2015-12-01

Expedition 351 of the International Ocean Discovery Program cored an Eocene section at Site U1438 in the Philippine Sea that provides insight into the early history of the Izu-Bonin arc. Subduction here is hypothesized to have initiated spontaneously, leaving a characteristic depositional sequence of post-subduction-initiation localized extension and volcanism. We conducted detailed macroscopic and microscopic study of the cores of the lowermost 100m of volcaniclastic and sedimentary rocks (Unit IV) directly overlying subduction initiation igneous basement, to identify depositional facies and trends. We subdivided Unit IV into three subunits based on lithologic characteristics. Transitions between the subunits are relatively abrupt, occurring within the length of a single core. The lowermost subunit (IVA) consists of 4 meters of laminated pelagic claystone with thin beds of graded volcaniclastic siltstone, and fine-grained tuff laminae composed of plagioclase feldspar and green-brown amphibole. The middle subunit (IVB) comprises 51 meters of texturally variable, thick-bedded, coarse-grained gravity flow deposits. These are composed of volcaniclastic sandstone and conglomerate containing glassy and tachylitic volcanic grains as well as sedimentary lithic fragments, along with traces of shallow-water carbonate bioclasts. Subunit IVB sediments are poorer in feldspar than IVA and contain only trace amphibole. They show variable grain rounding and an upsection increase in vitric components. Tachylite grains range from sub-angular to well rounded throughout, and other volcanic grain types show upward increases in angularity and vesicularity. The abrupt transition from pelagic sediments in subunit IVA to shallow-water-sourced gravity flows in subunit IVB suggests a rapid emergence of shallow-water to subaerial volcanic center early in the arc's development. The upper part of subunit IVB also contains igneous intrusions, providing possible evidence for more proximal

Slope-apron deposition in an ordovician arc-related setting: The Vuelta de Las Tolas Member (Suri Formation), Famatina Basin, northwest Argentina

Science.gov (United States)

Mangano, M.G.; Buatois, L.A.

1997-01-01

The Ordovician Suri Formation is part of the infill of the Famatina Basin of northwest Argentina, which formed in an active setting along the western margin of early Paleozoic Gondwana. The lower part of this formation, the Vuelta de Las Tolas Member, records sedimentation on a slope apron formed in an intra-arc basin situated on a flooded continental arc platform. The coincidence of a thick Arenig-Llanvirn sedimentary succession and volcanic-plutonic arc rocks suggests an extensional or transtensional arc setting, and is consistent with evidence of an extensional regime within the volcanic arc in the northern Puna region. The studied stratigraphic sections consist of volcanic rocks and six sedimentary facies. The facies can be clustered into four facies associations. Association 1, composed of facies A (laminated siltstones and mudstones) and B (massive mudstones and siltstones), is interpreted to have accumulated from silty-muddy high-and low-density turbidity currents and highly fluid, silty debris flows, with subsequent reworking by bottom currents, and to a lesser extent, hemipelagic suspension in an open-slope setting. Facies association 2 is dominated by facies C (current-rippled siltstones) strata. These deposits are interpreted to record overbank sedimentation from fine-grained turbidity currents. Facies E (matrix-supported volcanic breccias) interbedded with andesitic lava units comprises facies association 3. Deposition was contemporaneous with subaqueous volcanic activity, and accumulated from cohesive debris flows in a coarse-grained wedge at the base of slope. Facies association 4 is typified by facies D (vitric fine-grained sandstones and siltstones) and F (channelized and graded volcanic conglomerates and breccias) deposits. These strata commonly display thinning-and fining-upward trends, indicating sedimentation from highly-concentrated volcaniclastic turbidity currents in a channelized system. The general characteristics of these deposits of fresh

Nanašanje trdih zaščitnih prevlek s katodnim lokom: Cathodic arc plasma deposition of hard protective coatings:

OpenAIRE

Panjan, Peter

2002-01-01

The cathodic arc evaporation process is based upon the vacuum arc, the physics of which is still under investigation. This method is using almost exclusively for the deposition of wear-resistant coatings onto cutting and forming tools. The method is fast, effective, and relatively cost efficient. This paper reviews the arc evaporation process. Naparevanje s katodnim lokom temelji na plazemskem loku, ki ga prižegmo v vakuumu. Postopek se uporablja skoraj izključno za pripravo trdih zaščitni...

Quantification of amyloid deposits and oxygen extraction fraction in the brain with multispectral optoacoustic imaging in arcAβ mouse model of Alzheimer's disease

Science.gov (United States)

Ni, Ruiqing; Vaas, Markus; Rudin, Markus; Klohs, Jan

2018-02-01

Beta-amyloid (Aβ) deposition and vascular dysfunction are important contributors to the pathogenesis in Alzheimer's disease (AD). However, the spatio-temporal relationship between an altered oxygen metabolism and Aβ deposition in the brain remains elusive. Here we provide novel in-vivo estimates of brain Aβ load with Aβ-binding probe CRANAD-2 and measures of brain oxygen saturation by using multi-spectral optoacoustic imaging (MSOT) and perfusion imaging with magnetic resonance imaging (MRI) in arcAβ mouse models of AD. We demonstrated a decreased cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) in the cortical region of the arcAβ mice compared to wildtype littermates at 24 months. In addition, we showed proof-of-concept for the detection of cerebral Aβ deposits in brain from arcAβ mice compared to wild-type littermates.

Plasma streams mixing in two-channel t-shaped magnetic filter

International Nuclear Information System (INIS)

Aksyonov, D.S.; Aksenov, I.I.; Luchaninov, A.A.; Reshetnyak, E.N.; Strel'nitskij, V.E.

2011-01-01

Ti-Al-N films were deposited by vacuum arc method. T-shaped magnetic filter with two channels was used for films preparation. Deposition was performed after aluminum and titanium separate plasma streams from two plasma sources were mixed into single one inside plasma duct having weakened magnetic field near its output. Obtained films have uniform distribution of composition and thickness on 180 mm diameter substrate surface. It was found that mixing and homogenization degree depends on nitrogen pressure, output magnetic field intensity and output- to-substrate distance. Film self-sputtering and aluminum preferential sputtering were observed for elevated negative substrate bias potentials.

Heat treatment of cathodic arc deposited amorphous hard carbon films

Energy Technology Data Exchange (ETDEWEB)

Anders, S.; Ager, J.W. III; Brown, I.G. [and others

1997-02-01

Amorphous hard carbon films of varying sp{sup 2}/sp{sup 3} fractions have been deposited on Si using filtered cathodic are deposition with pulsed biasing. The films were heat treated in air up to 550 C. Raman investigation and nanoindentation were performed to study the modification of the films caused by the heat treatment. It was found that films containing a high sp{sup 3} fraction sustain their hardness for temperatures at least up to 400 C, their structure for temperatures up to 500 C, and show a low thickness loss during heat treatment. Films containing at low sp{sup 3} fraction graphitize during the heat treatment, show changes in structure and hardness, and a considerable thickness loss.

PM10 sampler deposited air particulates: Ascertaining uniformity of sample on filter through rotated exposure to radiation

International Nuclear Information System (INIS)

Owoade, Oyediran K.; Olise, Felix S.; Obioh, Imoh B.; Olaniyi, Hezekiah B.; Bolzacchini, Ezio; Ferrero, Luca; Perrone, Grazia

2006-01-01

For reproducibility of analytical results of samples deposited on filters using PM 10 sampler, homogeneity of the sample on the filter is very important especially when the size of the X-ray beam for the analysis is less than the size of filter. It is against this background that the air particulate samples collected on using PM 10 samplers are analysed to determine the elemental concentrations. Each sample was divided into four quadrants and each was analysed under same conditions to determine if the particles were deposited uniformly over the filter. Each analysis was done using EDXRF technique. The spectrometer consists of four secondary targets, which are automatically switched to in sequence in analysing each sample. The concentration of various elements detected was determined using TURBOQUANT (a brand name for a SPECTRO method which is used for screening analysis). Sixteen elements were detected in every sample. Results show that there was less than 10% deviation in the concentrations in different quadrants. There were a few elements like Ba, Cs, etc., which have deviation greater than 20%. The concentrations of these latter elements were close to detection limits of the spectrometer. We conclude that the analytical result of particulate samples deposited on filters by the PM 10 sampler can be reliable in terms of the homogeneity of the deposition. For such analytes with low concentrations, it would be important that the sampling time be increased to allow for higher mass deposition on the filter

Effect of arc behaviour on the temperature fluctuation of carbon electrode in DC arc discharge

International Nuclear Information System (INIS)

Liang, F; Tanaka, M; Choi, S; Watanabe, T

2014-01-01

Diffuse and multiple arc-anode attachment modes were observed in a DC arc discharge with a carbon electrode. During the arc discharge, the surface temperature of the electrode was successfully measured by two-colour pyrometry combined with a high-speed camera which employs appropriate band-pass filters. The relationship between the arc-anode attachment mode and the temperature fluctuation of electrode surface was investigated. The diffuse arc-anode attachment mode leads to relatively large temperature fluctuation on anode surface due to the rotation of the arc spot. In the case of diffuse mode, the purity of synthesized multi-wall carbon nanotube was deteriorated with temperature fluctuation

Study on effect of plasma surface treatments for diamond deposition by DC arc plasmatron.

Science.gov (United States)

Kang, In-Je; Joa, Sang-Beom; Lee, Heon-Ju

2013-11-01

To improve the thermal conductivity and wear resistance of ceramic materials in the field of renewable energy technologies, diamond coating by plasma processing has been carried out in recent years. This study's goal is to improve diamond deposition on Al2O3 ceramic substrates by plasma surface treatments. Before diamond deposition was carried out in a vacuum, plasma surface treatments using Ar gas were conducted to improve conditions for deposition. We also conducted plasma processing for diamond deposition on Al2O3 ceramic substrates using a DC arc Plasmatron. The Al2O3 ceramic substrates with diamond film (5 x 15 mm2), were investigated by SEM (Scanning Electron Microscopy), AFM (Atomic Force Microscopy) and XRD (X-ray Diffractometer). Then, the C-H stretching of synthetic diamond films by FTIR (Fourier Transform Infrared Spectroscopy) was studied. We identified nanocrystalline diamond films on the Al2O3 ceramic substrates. The results showed us that the deposition rate of diamond films was 2.3 microm/h after plasma surface treatments. Comparing the above result with untreated ceramic substrates, the deposition rate improved with the surface roughness of the deposited diamond films.

Numerical modelling of the erosion and deposition of sand inside a filter layer

DEFF Research Database (Denmark)

Jacobsen, Niels Gjøl; van Gent, Marcel R. A.; Fredsøe, Jørgen

2017-01-01

This paper treats the numerical modelling of the behaviour of a sand core covered by rocks and exposed to waves. The associated displacement of the rock is also studied. A design that allows for erosion and deposition of the sand core beneath a rock layer in a coastal structure requires an accurate...... prediction method to assure that the amount of erosion remains within acceptable limits. This work presents a numerical model that is capable of describing the erosion and deposition patterns inside of an open filter of rock on top of sand. The hydraulic loading is that of incident irregular waves...... and the open filters are surface piercing. Due to the few experimental data sets on sediment transport inside of rock layers, a sediment transport formulation has been proposed based on a matching between the numerical model and experimental data on the profile deformation inside an open filter. The rock layer...

PM{sub 10} sampler deposited air particulates: Ascertaining uniformity of sample on filter through rotated exposure to radiation

Energy Technology Data Exchange (ETDEWEB)

Owoade, Oyediran K. [Environmental Research Laboratory (ERL), Physics Department, Obafemi Awolowo University, Ile-Ife (Nigeria)]. E-mail: oowoade2001@yahoo.com; Olise, Felix S. [Environmental Research Laboratory (ERL), Physics Department, Obafemi Awolowo University, Ile-Ife (Nigeria); Obioh, Imoh B. [Centre for Energy Research, Development (Cerd), Obafemi Awolowo University, Ile-Ife (Nigeria); Olaniyi, Hezekiah B. [Environmental Research Laboratory (ERL), Physics Department, Obafemi Awolowo University, Ile-Ife (Nigeria); Bolzacchini, Ezio [Universita Milano-Bicocca, Dipartimento di Scienze-Ambientali, Pizza della Scienza, Milan (Italy); Ferrero, Luca [Universita Milano-Bicocca, Dipartimento di Scienze-Ambientali, Pizza della Scienza, Milan (Italy); Perrone, Grazia [Universita Milano-Bicocca, Dipartimento di Scienze-Ambientali, Pizza della Scienza, Milan (Italy)

2006-08-01

For reproducibility of analytical results of samples deposited on filters using PM{sub 10} sampler, homogeneity of the sample on the filter is very important especially when the size of the X-ray beam for the analysis is less than the size of filter. It is against this background that the air particulate samples collected on using PM{sub 10} samplers are analysed to determine the elemental concentrations. Each sample was divided into four quadrants and each was analysed under same conditions to determine if the particles were deposited uniformly over the filter. Each analysis was done using EDXRF technique. The spectrometer consists of four secondary targets, which are automatically switched to in sequence in analysing each sample. The concentration of various elements detected was determined using TURBOQUANT (a brand name for a SPECTRO method which is used for screening analysis). Sixteen elements were detected in every sample. Results show that there was less than 10% deviation in the concentrations in different quadrants. There were a few elements like Ba, Cs, etc., which have deviation greater than 20%. The concentrations of these latter elements were close to detection limits of the spectrometer. We conclude that the analytical result of particulate samples deposited on filters by the PM{sub 10} sampler can be reliable in terms of the homogeneity of the deposition. For such analytes with low concentrations, it would be important that the sampling time be increased to allow for higher mass deposition on the filter.

The application of imperialist competitive algorithm for optimization of deposition rate in submerged arc welding process using TiO2 nano particle

International Nuclear Information System (INIS)

Ghaderi, Mohammad Reza; Eslampanah, Amirhossein; Ghaderi, Kianoosh; Aghakhani, Masood

2015-01-01

We used a novel optimization algorithm based on the imperialist competitive algorithm (ICA) to optimize the deposition rate in the submerged arc welding (SAW) process. This algorithm offers some advantages such as simplicity, accuracy and time saving. Experiments were conducted based on a five factor, five level rotatable central composite design (RCCD) to collect welding data for deposition rate as a function of welding current, arc voltage, contact tip to plate distance, welding speed and thickness of TiO 2 nanoparticles coated on the plates of mild steel. Furthermore, regression equation for deposition rate was obtained using least squares method. The regression equation as the cost function was optimized using ICA. Ultimately, the levels of input variables to achieve maximum deposition rate were obtained using ICA. Computational results indicate that the proposed algorithm is quite effective and powerful in optimizing the cost function.

Vacuum arc plasma generation and thin film deposition from a TiB{sub 2} cathode

Energy Technology Data Exchange (ETDEWEB)

Zhirkov, Igor, E-mail: igozh@ifm.liu.se; Petruhins, Andrejs; Naslund, Lars-Ake; Rosen, Johanna [Thin Film Physics Division, Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-581 83 Linköping (Sweden); Kolozsvári, Szilard; Polcik, Peter [PLANSEE Composite Materials GmbH, Siebenbürgerstraße 23, 86983 Lechbruck am See (Germany)

2015-11-02

We have studied the utilization of TiB{sub 2} cathodes for thin film deposition in a DC vacuum arc system. We present a route for attaining a stable, reproducible, and fully ionized plasma flux of Ti and B by removal of the external magnetic field, which leads to dissipation of the vacuum arc discharge and an increased active surface area of the cathode. Applying a magnetic field resulted in instability and cracking, consistent with the previous reports. Plasma analysis shows average energies of 115 and 26 eV, average ion charge states of 2.1 and 1.1 for Ti and B, respectively, and a plasma ion composition of approximately 50% Ti and 50% B. This is consistent with measured resulting film composition from X-ray photoelectron spectroscopy, suggesting a negligible contribution of neutrals and macroparticles to the film growth. Also, despite the observations of macroparticle generation, the film surface is very smooth. These results are of importance for the utilization of cathodic arc as a method for synthesis of metal borides.

Carbon nanotubes and nanofibers synthesized by CVD on nickel coatings deposited with a vacuum arc

Energy Technology Data Exchange (ETDEWEB)

Escobar, M. [LP and MC, Dep. de Fisica-FCEyN-UBA, Cdad. Universitaria Pab.1, (1428), Buenos Aires (Argentina); DQIAQF-FCEyN-UBA, Cdad. Universitaria Pab.1, (1428), Buenos Aires (Argentina); Giuliani, L. [INFIP, CONICET, Dep. de Fisica, FCEyN-UBA, Cdad. Univ. Pab.1, (1428), Buenos Aires (Argentina); Candal, R.J. [INQUIMAE-FCEyN-UBA, Cdad. Universitaria Pab.2, (1428), Buenos Aires (Argentina); Lamas, D.G. [CINSO, CITEFA, CONICET, J.B. de La Salle 4397, (1603) V.Martelli, Buenos Aires (Argentina); Caso, A. [LP and MC, Dep. de Fisica-FCEyN-UBA, Cdad. Universitaria Pab.1, (1428), Buenos Aires (Argentina); Rubiolo, G. [LP and MC, Dep. de Fisica-FCEyN-UBA, Cdad. Universitaria Pab.1, (1428), Buenos Aires (Argentina); UAM-CNEA, Av. Gral Paz 1499, (1650) San Martin, Buenos Aires (Argentina); Grondona, D. [INFIP, CONICET, Dep. de Fisica, FCEyN-UBA, Cdad. Univ. Pab.1, (1428), Buenos Aires (Argentina); Goyanes, S. [LP and MC, Dep. de Fisica-FCEyN-UBA, Cdad. Universitaria Pab.1, (1428), Buenos Aires (Argentina); Marquez, A., E-mail: amarquez@df.uba.a [INFIP, CONICET, Dep. de Fisica, FCEyN-UBA, Cdad. Univ. Pab.1, (1428), Buenos Aires (Argentina)

2010-04-16

Nanotubes and nanofibers were grown on Ni coatings deposited by plasma generated with a pulsed vacuum arc on silicon wafers using three different bias conditions: at floating potential (approximately +30 V respect to the grounded cathode); at ground potential; and at -60 V. An atomic force microscopy study showed that the Ni film morphology was affected by the bias condition of the substrate. The morphology of carbonaceous species depended on Ni-films characteristics. FE-SEM and TEM analyses have shown that nanofibers growth was favoured on Ni coatings deposited at -60 V whereas nanotubes grew mainly on Ni coatings obtained at floating and ground potentials. Hence, this new method to produce the precursor can be optimized to obtain nanotubes or nanofibers varying the substrate bias for the Ni deposition.

The application of imperialist competitive algorithm for optimization of deposition rate in submerged arc welding process using TiO{sub 2} nano particle

Energy Technology Data Exchange (ETDEWEB)

Ghaderi, Mohammad Reza; Eslampanah, Amirhossein; Ghaderi, Kianoosh [Islamic Azad University, Sanandaj (Iran, Islamic Republic of); Aghakhani, Masood [Razi University, Kermanshah (Iran, Islamic Republic of)

2015-01-15

We used a novel optimization algorithm based on the imperialist competitive algorithm (ICA) to optimize the deposition rate in the submerged arc welding (SAW) process. This algorithm offers some advantages such as simplicity, accuracy and time saving. Experiments were conducted based on a five factor, five level rotatable central composite design (RCCD) to collect welding data for deposition rate as a function of welding current, arc voltage, contact tip to plate distance, welding speed and thickness of TiO{sub 2} nanoparticles coated on the plates of mild steel. Furthermore, regression equation for deposition rate was obtained using least squares method. The regression equation as the cost function was optimized using ICA. Ultimately, the levels of input variables to achieve maximum deposition rate were obtained using ICA. Computational results indicate that the proposed algorithm is quite effective and powerful in optimizing the cost function.

CrAlN coatings deposited by cathodic arc evaporation at different substrate bias

International Nuclear Information System (INIS)

Romero, J.; Gomez, M.A.; Esteve, J.; Montala, F.; Carreras, L.; Grifol, M.; Lousa, A.

2006-01-01

CrAlN is a good candidate as an alternative to conventional CrN coatings especially for high temperature oxidation-resistance applications. Different CrAlN coatings were deposited on hardened steel substrates by cathodic arc evaporation (CAE) from chromium-aluminum targets in a reactive nitrogen atmosphere at negative substrate bias between - 50 and - 400 V. The negative substrate bias has important effects on the deposition growth rate and crystalline structure. All our coatings presented hardness higher than conventional CrN coatings. The friction coefficient against alumina and tungsten carbide balls was around 0.6. The sliding wear coefficient of the CrAlN coatings was very low while an important wear was observed in the balls before a measurable wear were produced in the coatings. This effect was more pronounced as the negative substrate bias was increased

Sphagnum can 'filter' N deposition, but effects on the plant and pore water depend on the N form.

Science.gov (United States)

Chiwa, Masaaki; Sheppard, Lucy J; Leith, Ian D; Leeson, Sarah R; Tang, Y Sim; Cape, J Neil

2016-07-15

The ability of Sphagnum moss to efficiently intercept atmospheric nitrogen (N) has been assumed to be vulnerable to increased N deposition. However, the proposed critical load (20kgNha(-1)yr(-1)) to exceed the capacity of the Sphagnum N filter has not been confirmed. A long-term (11years) and realistic N manipulation on Whim bog was used to study the N filter function of Sphagnum (Sphagnum capillifolium) in response to increased wet N deposition. On this ombrotrophic peatland where ambient deposition was 8kgNha(-1)yr(-1), an additional 8, 24, and 56kgNha(-1)yr(-1) of either ammonium (NH4(+)) or nitrate (NO3(-)) has been applied for 11years. Nutrient status of Sphagnum and pore water quality from the Sphagnum layer were assessed. The N filter function of Sphagnum was still active up to 32kgNha(-1)yr(-1) even after 11years. N saturation of Sphagnum and subsequent increases in dissolved inorganic N (DIN) concentration in pore water occurred only for 56kgNha(-1)yr(-1) of NH4(+) addition. These results indicate that the Sphagnum N filter is more resilient to wet N deposition than previously inferred. However, functionality will be more compromised when NH4(+) dominates wet deposition for high inputs (56kgNha(-1)yr(-1)). The N filter function in response to NO3(-) uptake increased the concentration of dissolved organic N (DON) and associated organic anions in pore water. NH4(+) uptake increased the concentration of base cations and hydrogen ions in pore water though ion exchange. The resilience of the Sphagnum N filter can explain the reported small magnitude of species change in the Whim bog ecosystem exposed to wet N deposition. However, changes in the leaching substances, arising from the assimilation of NO3(-) and NH4(+), may lead to species change. Copyright © 2016 Elsevier B.V. All rights reserved.

Production of thin carbon stripper foils using heated-substrates in a cathodic arc deposition system

International Nuclear Information System (INIS)

Merchant, A.R.; Lobanov, N.; Elliman, R.G.; Ophel, T.R.; Rode, A.; Weisser, D.C.; Turkentine, R.B.

1998-01-01

The lifetime of carbon stripper foil can have a marked impact on the successful running of a beam line. Standard techniques for production of carbon stripper foils include evaporation of carbon (ec) and laser-pulsed ablation (Ipa). Recent work by a using Ipa has been successful in substantially increasing the lifetime of a very thin foil. The suspected mechanism for the increased lifetime of the foil is that the amorphous carbon foil is density-matched to that of graphite (around 2.26g/cc). In this work, we attempt to reproduce this result by producing carbon stripper foils with a mass-density similar to graphite using a cathodic arc deposition system. The cathodic arc is well known for the production of tetrahedral amorphous carbon: a high density, high stress form of carbon with over 90% sp 3 -like bonds; to reduce the density of the carbon and promote more graphitic structure, a high bias was initially attempted but this proved unsuccessful. Another method is to use a heated-substrate holder to reduce compressive stress within the deposited film. The performance of the density-matched carbon stripper foils and the implications for future production of high-quality carbon stripper foils in our laboratory will be discussed. (authors)

In-situ deposition of sacrificial layers during ion implantation

International Nuclear Information System (INIS)

Anders, A.; Anders, S.; Brown, I.G.; Yu, K.M.

1995-02-01

The retained dose of implanted ions is limited by sputtering. It is known that a sacrificial layer deposited prior to ion implantation can lead to an enhanced retained dose. However, a higher ion energy is required to obtain a similar implantation depth due to the stopping of ions in the sacrificial layer. It is desirable to have a sacrificial layer of only a few monolayers thickness which can be renewed after it has been sputtered away. We explain the concept and describe two examples: (i) metal ion implantation using simultaneously a vacuum arc ion source and filtered vacuum arc plasma sources, and (ii) Metal Plasma Immersion Ion Implantation and Deposition (MePIIID). In MePIIID, the target is immersed in a metal or carbon plasma and a negative, repetitively pulsed bias voltage is applied. Ions are implanted when the bias is applied while the sacrificial layer suffers sputtering. Low-energy thin film deposition - repair of the sacrificial layer -- occurs between bias pulses. No foreign atoms are incorporated into the target since the sacrificial film is made of the same ion species as used in the implantation phase

Deposition Uniformity of Coal Dust on Filters and Its Effect on the Accuracy of FTIR Analyses for Silica.

Science.gov (United States)

Miller, Arthur L; Drake, Pamela L; Murphy, Nathaniel C; Cauda, Emanuele G; LeBouf, Ryan F; Markevicius, Gediminas

Miners are exposed to silica-bearing dust which can lead to silicosis, a potentially fatal lung disease. Currently, airborne silica is measured by collecting filter samples and sending them to a laboratory for analysis. Since this may take weeks, a field method is needed to inform decisions aimed at reducing exposures. This study investigates a field-portable Fourier transform infrared (FTIR) method for end-of-shift (EOS) measurement of silica on filter samples. Since the method entails localized analyses, spatial uniformity of dust deposition can affect accuracy and repeatability. The study, therefore, assesses the influence of radial deposition uniformity on the accuracy of the method. Using laboratory-generated Minusil and coal dusts and three different types of sampling systems, multiple sets of filter samples were prepared. All samples were collected in pairs to create parallel sets for training and validation. Silica was measured by FTIR at nine locations across the face of each filter and the data analyzed using a multiple regression analysis technique that compared various models for predicting silica mass on the filters using different numbers of "analysis shots." It was shown that deposition uniformity is independent of particle type (kaolin vs. silica), which suggests the role of aerodynamic separation is negligible. Results also reflected the correlation between the location and number of shots versus the predictive accuracy of the models. The coefficient of variation (CV) for the models when predicting mass of validation samples was 4%-51% depending on the number of points analyzed and the type of sampler used, which affected the uniformity of radial deposition on the filters. It was shown that using a single shot at the center of the filter yielded predictivity adequate for a field method, (93% return, CV approximately 15%) for samples collected with 3-piece cassettes.

Dosimetric Impact of the Interplay Effect During Stereotactic Lung Radiation Therapy Delivery Using Flattening Filter-Free Beams and Volumetric Modulated Arc Therapy

International Nuclear Information System (INIS)

Ong, Chin Loon; Dahele, Max; Slotman, Ben J.; Verbakel, Wilko F.A.R.

2013-01-01

Purpose: We investigated the dosimetric impact of the interplay effect during RapidArc stereotactic body radiation therapy for lung tumors using flattening filter-free (FFF) beams with different dose rates. Methods and Materials: Seven tumors with motion ≤20 mm, treated with 10-MV FFF RapidArc, were analyzed. A programmable phantom with sinusoidal longitudinal motion (30-mm diameter “tumor” insert; period = 5 s; individualized amplitude from planning 4-dimensional computed tomography) was used for dynamic dose measurements. Measurements were made with GafChromic EBT III films. Plans delivered the prescribed dose to 95% of the planning target volume, created by a 5-mm expansion of the internal target volume. They comprised 2 arcs and maximum dose rates of 400 and 2400 MU/min. For 2400 MU/min plans, measurements were repeated at 3 different initial breathing phases to model interplay over 2 to 3 fractions. For 3 cases, 2 extra plans were created using 1 full rotational arc (with contralateral lung avoidance sector) and 1 partial arc of 224° to 244°. Dynamic and convolved static measurements were compared by use of gamma analysis of 3% dose difference and 1 mm distance-to-agreement. Results: For 2-arc 2400 MU/min plans, maximum dose deviation of 9.4% was found in a single arc; 7.4% for 2 arcs (single fraction) and 99% of the area within the region of interest passed the gamma criteria when all 3 measurements with different initial phases were combined. Single-fraction single-arc plans showed higher dose deviations, which diminished when dose distributions were summed over 2 fractions. All 400 MU/min plans showed good agreement in a single fraction measurement. Conclusion: Under phantom conditions, single-arc and single-fraction 2400 MU/min FFF RapidArc lung stereotactic body radiation therapy is susceptible to interplay. Two arcs and ≥2 fractions reduced the effect to a level that appeared unlikely to be clinically significant

Vacuum arc plasma deposition of thin titanium dioxide films on silicone elastomer as a functional coating for medical applications

Energy Technology Data Exchange (ETDEWEB)

Boudot, Cécile, E-mail: cecile.boudot@tum.de [Technical University of Munich, Department of Mechanical Engineering, Boltzmannstraße 15, D-85748 Garching bei München (Germany); Kühn, Marvin; Kühn-Kauffeldt, Marina; Schein, Jochen [Institute for Plasma Technology and Mathematics, University of Federal Armed Forces Munich, Werner-Heisenberg-Weg 39, D-85577 Neubiberg (Germany)

2017-05-01

Silicone elastomer is a promising material for medical applications and is widely used for implants with blood and tissue contact. However, its strong hydrophobicity limits adhesion of tissue cells to silicone surfaces, which can impair the healing process. To improve the biological properties of silicone, a triggerless pulsed vacuum cathodic arc plasma deposition technique was applied to deposit titanium dioxide (TiO{sub 2}) films onto the surface. Scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and contact angle measurements were used for coating characterization. Deposited films were about 150 nm thick and exhibited good adhesion to the underlying silicone substrate. Surface wettability and roughness both increased after deposition of the TiO{sub 2} layer. In addition, cell-biological investigations demonstrated that the in-vitro cytocompatibility of TiO{sub 2}-coated samples was greatly improved without impacting silicone's nontoxicity. For validation of use in medical devices, further investigations were conducted and demonstrated stability of surface properties in an aqueous environment for a period of 68 days and the coating's resistance to several sterilization methods. - Highlights: • Vacuum arc plasma was applied to deposit titanium dioxide films onto silicone. • Thickness, roughness and composition of the films were determined. • Cytocompatibility of coated silicone elastomer is greatly improved. • Films have good adhesion to the substrate and are stable, non-toxic and sterilizable.

Age and geochemistry of host rocks of the Cobre Panama porphyry Cu-Au deposit, central Panama: Implications for the Paleogene evolution of the Panamanian magmatic arc

Science.gov (United States)

Baker, Michael J.; Hollings, Peter; Thompson, Jennifer A.; Thompson, Jay M.; Burge, Colin

2016-04-01

The Cobre Panama porphyry Cu-Au deposit, located in the Petaquilla district of central Panama, is hosted by a sequence of medium- to high-K calc-alkaline volcanic and sub-volcanic rocks. New crystallisation ages obtained from a granodiorite Petaquilla batholith and associated mineralised diorite to granodiorite porphyry stocks and dikes at Cobre Panama indicate that the batholith was emplaced as a multi-phase intrusion, over a period of 4 million years from 32.20 ± 0.76 Ma to 28.26 ± 0.61 Ma, while the porphyritic rocks were emplaced over a 2 million year period from 28.96 ± 0.62 Ma to 27.48 ± 0.68 Ma. Both the volcanic to sub-volcanic host rocks and intrusive rocks of the Cobre Panama deposit evolved via fractional crystallisation processes, as demonstrated by the major elements (e.g. Al2O3, Fe2O3, TiO2 and MgO) displaying negative trends with increasing SiO2. The Petaquilla intrusive rocks, including the diorite-granodiorite porphyries and granodiorite batholith, are geochemically evolved and appear to have formed from more hydrous magmas than the preceding host volcanic rocks, as evidenced by the presence of hornblende phenocrysts, higher degrees of large-ion lithophile element (LILE) and light rare earth element (LREE) enrichment and heavy rare earth element (HREE) depletion, and higher Sr/Y and La/Yb values. However, the degree of LREE enrichment, HREE depletion and La/Yb values are insufficient for the intrusive rocks to be considered as adakites. Collectively, the volcanic and intrusive rocks have LILE, REE and mobile trace element concentrations similar to enriched Miocene-age Cordilleran arc magmatism found throughout central and western Panama. Both the Petaquilla and Cordilleran arc magmatic suites are geochemically more evolved than the late Cretaceous to Eocene Chagres-Bayano arc magmas from northeastern Panama, as they display higher degrees of LILE and LREE enrichment. The geochemical similarities between the Petaquilla and Cordilleran arc magmas

Multilayer Ti-Cr-N Coatings Produced by the Vacuum-Arc Deposition

International Nuclear Information System (INIS)

Kunchenko, Yu.V.; Kunchenko, V.V.; Neklyudov, I.M.; Kartmazov, G.N.; Andreev, A.A.

2007-01-01

A possibility is demonstrated for nanolayer TiN x /CrN x coating formation by the method of vacuum-arc deposition on the substrate, which being rotated around the 'Bulat'-type chamber axis intercepts sequentially the plasma flows generated by three evaporators. The model for calculating the coating deposition rate (thickness) was used to determine the geometrical parameters that provide the formation of layer structures in the nanometer range. The variations of phase-structure characteristics, compression microstresses (σ) microhardness (H v ) of the coating formed have been investigated as functions of nitrogen pressure (P N =0.001...1.0 Pa), bias voltage (U=-100...-300 V) and condensation temperature (T C =330...750 degree C) at focusing magnetic field strength H F =0; 35 and 100 Oe. The mentioned field strengths were responsible for the ion current densities (j∼5,8...10 and ≥15 mA/cm 2 ). A nonmonotonic behaviour of H v as a function of condensation temperature and of vacuum annealing temperature has been established. The maximum H v values (∼35...37 GPa) were observed in the 450...500 degree C range

Effect of deposition strategy on the microstructure and mechanical properties of Inconel 625 superalloy fabricated by pulsed plasma arc deposition

International Nuclear Information System (INIS)

Xu, F.J.; Lv, Y.H.; Xu, B.S.; Liu, Y.X.; Shu, F.Y.; He, P.

2013-01-01

Highlights: ► PPAD Inconel 625 sample deposited with ICS strategy exhibits improved surface quality. ► ICS sample exhibits finer microstructure and improved mechanical properties. ► Higher level γ′ and γ″ phases are precipitated in the ICS sample. ► STA heat treatment reduced the concentration of Nb element. ► STA heat treatment improved the mechanical properties of PPAD Inconel 625. -- Abstract: Pulsed plasma arc deposition (PPAD), which combines pulsed plasma cladding with rapid prototyping, is a promising technology for manufacturing near net shape components due to its superiority in cost and convenience of processing. The aim of this study was to investigate the influences of interpass cooling strategy (ICS) and continuous deposition strategy (CDS) on microstructure and mechanical properties of the PPAD Inconel 625 non-ferrous alloy. The as-deposited samples in the two conditions were subjected to the post heat treatment: 980 °C solution treatment + direct aging (STA). The microstructures and mechanical properties of the samples were characterized by means of scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS), transmission electron microscopy (TEM), micro-hardness and tensile testers. It was found that the as-deposited microstructure exhibited homogenous cellular dendrite structure, which grew epitaxially along the deposition direction. The as-deposited microstructure of ICS sample revealed smaller dendritic arm spacing, less niobium segregation and discontinuous finer Laves phase in the interdendritic regions compared to the case of continuous deposition strategy (CDS). The ICS sample exhibited better mechanical properties than CDS sample. After STA heat treatment, a large amount of Laves particles in the interdendritic regions were dissolved, resulting in the reduction of Nb segregation and the precipitation of needle-like δ (Ni 3 Nb). The tensile and yield strength of the as-deposited samples were

An apparatus for sequential pulsed plasma beam treatment in combination with Arc PVD deposition

International Nuclear Information System (INIS)

Stanislawski, J.; Werner, Z.; Piekoszewski, J.; Richter, E.

2002-01-01

A hybrid type of apparatus is described which enables one to form a thin multi-layer film on the surface of any kind of solid substrate. In one process, the surface is treated with a high intensity pulse plasma beam which introduces the chosen kind of atoms into the near-surface layer of the substrate. In the second process, following the first without breaking the vacuum, the coating is formed by arc PVD (physics vapour deposition) process. Two examples of coatings formed on metallic and ceramic substrates are presented. (author)

Investigation and control of dc arc jet instabilities to obtain a self-sustained pulsed laminar arc jet

International Nuclear Information System (INIS)

Krowka, J; Rat, V; Coudert, J F

2013-01-01

The uncontrolled arc plasma instabilities in suspension plasma spraying or solution precursor plasma spraying cause non-homogeneous plasma treatments of material during their flight and also on coatings during their formation. This paper shows that the arc motion in dc plasma torches mainly originates in two main modes of oscillation (Helmholtz and restrike modes). The emphasis is put on the restrike mode in which the time component is extracted after building up and applying a numerical filter to raw arc voltage signals. The dependence of re-arcing events on experimental parameters is analysed in the frame of a phenomenological restrike model. It is shown that when the restrike frequency reaches the Helmholtz one, both modes are locked together and a pulsed arc jet is generated. (paper)

Influence of bias voltage on properties of AlCrN coatings prepared by cathodic arc deposition

International Nuclear Information System (INIS)

Lomello, F.; Sanchette, F.; Schuster, F.; Tabarant, M.; Billard, A.

2013-01-01

AlCrN coatings were prepared by vacuum cathodic arc deposition. This low-temperature technique has been chosen due to its versatility, allowing the industrial up-scaling. In this study, the attention was focused on the correlation of the bias voltage with the resulting mechanical-tribological properties. For this purpose, the bias voltage was varied from 0 to -150 V. Indeed, the variation of grain sizes from 24 to 16 nm as well as the residual stresses from -0.68 to -8.94 GPa lead to obtain different mechanical-tribological properties. In this context, the sample deposited at -100 V exhibited an enhanced hardness (50 ± 2 GPa) and an acceptable wear resistance. (authors)

Surface hardening of optic materials by deposition of diamond like carbon coatings from separated plasma of arc discharge

Science.gov (United States)

Osipkov, A. S.; Bashkov, V. M.; Belyaeva, A. O.; Stepanov, R.; Mironov, Y. M.; Galinovsky, A. L.

2015-02-01

This article considers the issue of strengthening of optic materials used in the IR spectrum by deposition of diamond like carbon coatings from separated plasma arc discharge. The report shows results of tests of bare and strengthened optical materials such as BaF2, MgF2, Si, Ge, including the testing of their strength and spectral characteristics. Results for the determination of optical constants for the DLC coatings deposited on substrates of Ge and Si, by using separated plasma, are also presented. Investigations showed that surface hardening of optical materials operable in the IR range, by the deposition of diamond like carbon coating onto their surface, according to this technology, considerably improves operational properties and preserves or improves their optic properties.

Numerical Prediction of the Influence of Process Parameters on Large Area Diamond Deposition by DC Arcjet with ARC Roots Rotating and Operating at Gas Recycling Mode

Science.gov (United States)

Lu, F. X.; Huang, T. B.; Tang, W. Z.; Song, J. H.; Tong, Y. M.

A computer model have been set up for simulation of the flow and temperature field, and the radial distribution of atomic hydrogen and active carbonaceous species over a large area substrate surface for a new type dc arc plasma torch with rotating arc roots and operating at gas recycling mode A gas recycling radio of 90% was assumed. In numerical calculation of plasma chemistry, the Thermal-Calc program and a powerful thermodynamic database were employed. Numerical calculations to the computer model were performed using boundary conditions close to the experimental setup for large area diamond films deposition. The results showed that the flow and temperature field over substrate surface of Φ60-100mm were smooth and uniform. Calculations were also made with plasma of the same geometry but no arc roots rotation. It was clearly demonstrated that the design of rotating arc roots was advantageous for high quality uniform deposition of large area diamond films. Theoretical predictions on growth rate and film quality as well as their radial uniformity, and the influence of process parameters on large area diamond deposition were discussed in detail based on the spatial distribution of atomic hydrogen and the carbonaceous species in the plasma over the substrate surface obtained from thermodynamic calculations of plasma chemistry, and were compared with experimental observations.

Sedimentary processes in modern and ancient oceanic arc settings: evidence from the Jurassic Talkeetna Formation of Alaska and the Mariana and Tonga Arcs, western Pacific

Science.gov (United States)

Draut, Amy E.; Clift, Peter D.

2006-01-01

Sediment deposited around oceanic volcanic ares potentially provides the most complete record of the tectonic and geochemical evolution of active margins. The use of such tectonic and geochemical records requires an accurate understanding of sedimentary dynamics in an arc setting: processes of deposition and reworking that affect the degree to which sediments represent the contemporaneous volcanism at the time of their deposition. We review evidence from the modern Mariana and Tonga arcs and the ancient arc crustal section in the Lower Jurassic Talkeetna Formation of south-central Alaska, and introduce new data from the Mariana Arc, to produce a conceptual model of volcaniclastic sedimentation processes in oceanic arc settings. All three arcs are interpreted to have formed in tectonically erosive margin settings, resulting in long-term extension and subsidence. Debris aprons composed of turbidites and debris flow deposits occur in the immediate vicinity of arc volcanoes, forming relatively continuous mass-wasted volcaniclastic records in abundant accommodation space. There is little erosion or reworking of old volcanic materials near the arc volcanic front. Tectonically generated topography in the forearc effectively blocks sediment flow from the volcanic front to the trench; although some canyons deliver sediment to the trench slope, most volcaniclastic sedimentation is limited to the area immediately around volcanic centers. Arc sedimentary sections in erosive plate margins can provide comprehensive records of volcanism and tectonism spanning arc may be best reconstructed from sediments of the debris aprons for intervals up to ~ 20 My but no longer, because subduction erosion causes migration of the forearc basin crust and its sedimentary cover toward the trench, where there is little volcaniclastic sedimentation and where older sediments are dissected and reworked along the trench slope.

Can volumetric modulated arc therapy with flattening filter free beams play a role in stereotactic body radiotherapy for liver lesions? A volume-based analysis

International Nuclear Information System (INIS)

Reggiori, Giacomo; Mancosu, Pietro; Castiglioni, Simona; Alongi, Filippo; Pellegrini, Chiara; Lobefalo, Francesca; Catalano, Maddalena; Fogliata, Antonella; Arcangeli, Stefano; Navarria, Piera; Cozzi, Luca; Scorsetti, Marta

2012-01-01

Purpose: To compare volumetric modulated arc therapy with flattening filter free (FFF) and flattening filter (FF) beams in patients with hepatic metastases subject to hypofractionated radiotherapy (RT). Methods: A planning study on 13 virtual lesions of increasing volume was performed. Two single arc plans were optimized with the RapidArc technique using either FFF or FF beams. A second planning study was performed on ten patients treated for liver metastases to validate conclusions. In all cases, a dose of 75 Gy in 3 fractions was prescribed to the planning target volume (PTV) and plans were evaluated in terms of coverage, homogeneity, conformity, mean dose to healthy liver and to healthy tissue. For each parameter, results were expressed in relative terms as the percentage ratio between FFF and FF data. Results: In terms of PTV coverage, conformity index favored FFF for targets of intermediate size while FF resulted more suitable for small ( 3 ) and large (>300 cm 3 ) targets. Plans optimized with FFF beams resulted in increased sparing of healthy tissue in ≅85% of cases. Despite the qualitative results, no statistically significant differences were found between FFF and FF results. Plans optimized with un-flattened beams resulted in higher average MU/Gy than plans with FF beams. A remarkable and significant difference was observed in the beam-on time (BOT) needed to deliver plans. The BOT for FF plans was 8.2 ± 1.0 min; for FFF plans BOT was 2.2 ± 0.2 min. Conclusions: RapidArc plans optimized using FFF were dosimetrically equivalent to those optimized using FF beams, showing the feasibility of SBRT treatments with FFF beams. Some improvement in healthy tissue sparing was observed when using the FFF modality due to the different beam's profile. The main advantage was a considerable reduction of beam-on time, relevant for SBRT techniques.

Dosimetric study of RapidArc plans with flattened beam (FB and flattening filter-free (FFF beam for localized prostate cancer based on physical indices

Directory of Open Access Journals (Sweden)

Birendra Kumar Rout

2014-12-01

Full Text Available Purpose: To identify the continual diversity between flattening photon beam (FB and Flattening Filter Free (FFF photon beams for localized prostate cancer; and to determine potential benefits and drawbacks of using unflattened beam for this type of treatment.Methods: Eight prostate cases including seminal vesicles selected for this study. The primary planning target volume (PTVP and boost planning target volume (PTVB were contoured. The total prescription dose was 78 Gy (56 Gy to PTVP and an additional 22 Gy to PTVB. For all cases, treatment plans using 6MV with FB and FFF beams with identical dose-volume constraints, arc angles and number of arcs were developed. The dose volume histograms for both techniques were compared for primary target volume and critical structures.Results: A low Sigma index (FFF: 1.65 + 0.361; FB: 1.725 + 0.39 indicating improved dose homogeneity in FFF beam. Conformity index (FFF: 0.994 + 0.01; FB: 0.993 + 0.01 is comparable for both techniques. Minimal difference of Organ at risk mean dose was observed. Normal tissue integral dose in FB plan resulted 1.5% lower than FFF plan. All the plans displayed significant increase (1.18 times for PTVP and 1.11 for PTBB in the average number of necessary MU with FFF beam.Conclusion: Diversity between FB and FFF beam plans were found. FFF beam accelerator has been utilized to develop clinically acceptable Rapid Arc treatment plans for prostate cancer with 6 MV.---------------------------------Cite this article as: Rout BK, Muralidhar KR, Ali M, Shekar MC, Kumar A. Dosimetric study of RapidArc plans with flattened beam (FB and flattening filter-free (FFF beam for localized prostate cancer based on physical indices. Int J Cancer Ther Oncol 2014; 2(4:02046.  DOI: 10.14319/ijcto.0204.6

The application of magnetic self-filter to optimization of AIN film growth process during the impulse plasma deposition synthesis

Directory of Open Access Journals (Sweden)

Chodun Rafal

2016-03-01

Full Text Available This work presents the very first results of the application of plasma magnetic filtering achieved by a coil coupled with an electrical circuit of a coaxial accelerator during the synthesis of A1N thin films by use of Impulse Plasma Deposition method (IPD. The uniqueness of this technical solution lies in the fact that the filter is not supplied, controlled and synchronized from any external device. Our solution uses the energy from the electrical circuit of plasma accelerator. The plasma state was described on the basis of OES studies. Estimation of the effects of plasma filtering on the film quality was carried out on the basis of characterization of structure morphology (SEM, phase and chemical composition (vibrational spectroscopy. Our work has shown that the use of the developed magnetic self-filter improved the structure of the AlN coatings synthesized under the condition of impulse plasma, especially by the minimization of the tendency to deposit metallic aluminum droplets and columnar growth.

Structure and corrosion properties of Cr coating deposited on aerospace bearing steel

Science.gov (United States)

Wang, Fangfang; Zhang, Fengxiang; Zheng, Lijing; Zhang, Hu

2017-11-01

The corrosion protection of chromium coating deposited on aerospace bearing steels by using the Filtered Cathodic Vacuum Arc deposition- Metal Evaporation Vacuum Arc duplex technique (MEVVA-FCVA) had been investigated. The protection efficiency of chromium coating on different substrate materials had also been evaluated. The chromium coating was mainly composed of nanocrystallineα-Cr in a range of 50-200 nm. The orientation distributions of α-Cr film on substrates with different composition had a certain difference to each other. Electrochemical experimental results indicated that the chromium coating significantly improved the corrosion resistance of experimental bearing steels in 3.5% NaCl solution. The protective efficiency of chromium films were all over 98%. The corrosion resistance of chromium coating was influenced by the chemical composition of substrate material. The chromium coatings on higher Cr-containing substrate displayed lower corrosion current density and more positive corrosion potential. The increase of passive film thickness and the formation of a mass of chromium oxide and hydroxide on the surface are responsible for the improved corrosion properties.

THE REAL ISSUE WITH WALL DEPOSITS IN CLOSED FILTER CASSETTES - WHAT'S THE SAMPLE?

Energy Technology Data Exchange (ETDEWEB)

Brisson, M.

2009-09-12

The measurement of aerosol dusts has long been utilized to assess the exposure of workers to metals. Tools used to sample and measure aerosol dusts have gone through many transitions over the past century. In particular, there have been several different techniques used to sample for beryllium, not all of which might be expected to produce the same result. Today, beryllium samples are generally collected using filters housed in holders of several different designs, some of which are expected to produce a sample that mimics the human capacity for dust inhalation. The presence of dust on the interior walls of cassettes used to hold filters during metals sampling has been discussed in the literature for a number of metals, including beryllium, with widely varying data. It appears that even in the best designs, particulates can enter the sampling cassette and deposit on the interior walls rather than on the sampling medium. The causes are not well understood but are believed to include particle bounce, electrostatic forces, particle size, particle density, and airflow turbulence. Historically, the filter catch has been considered to be the sample, but the presence of wall deposits, and the potential that the filter catch is not representative of the exposure to the worker, puts that historical position into question. This leads to a fundamental question: What is the sample? This article reviews the background behind the issue, poses the above-mentioned question, and discusses options and a possible path forward for addressing that question.

View of an intact oceanic arc, from surficial to mesozonal levels: Cretaceous Alisitos arc, Baja California

Science.gov (United States)

Busby, Cathy; Fackler Adams, Benjamin; Mattinson, James; Deoreo, Stephen

2006-01-01

The Alisitos arc is an approximately 300 × 30 km oceanic arc terrane that lies in the western wall of the Peninsular Ranges batholith south of the modern Agua Blanca fault zone in Baja California. We have completed detailed mapping and dating of a 50 × 30 km segment of this terrane in the El Rosario to Mission San Fernando areas, as well as reconnaissance mapping and dating in the next 50 × 30 km segment to the north, in the San Quintin area. We recognize two evolutionary phases in this part of the arc terrane: (I) extensional oceanic arc, characterized by intermediate to silicic explosive and effusive volcanism, culminating in caldera-forming silicic ignimbrite eruptions at the onset of arc rifting, and (II) rifted oceanic arc, characterized by mafic effusive and hydroclastic rocks and abundant dike swarms. Two types of units are widespread enough to permit tentative stratigraphic correlation across much of this 100-km-long segment of the arc: a welded dacite ignimbrite (tuff of Aguajito), and a deepwater debris-avalanche deposit. New U-Pb zircon data from the volcanic and plutonic rocks of both phases indicate that the entire 4000-m-thick section accumulated in about 1.5 MY, at 111-110 MY. Southwestern North American sources for two zircon grains with Proterozoic 206Pb / 207Pb ages support the interpretation that the oceanic arc fringed North America rather than representing an exotic terrane. The excellent preservation and exposure of the Alistos arc terrane makes it ideal for three-dimensional study of the structural, stratigraphic and intrusive history of an oceanic arc terrane. The segment mapped and dated in detail has a central major subaerial edifice, flanked by a down-faulted deepwater marine basin to the north, and a volcano-bounded shallow-water marine basin to the south. The rugged down-faulted flank of the edifice produced mass wasting, plumbed large-volume eruptions to the surface, and caused pyroclastic flows to disintegrate into turbulent

Durable superhydrophobic and superoleophilic filter paper for oil–water separation prepared by a colloidal deposition method

International Nuclear Information System (INIS)

Du, Chuan; Wang, Jiadao; Chen, Zhifu; Chen, Darong

2014-01-01

Graphical abstract: - Highlights: • A method for fabricating durable superhydrophobic filter paper was developed. • Oil–water separation efficiency exceeds 99% using the as-prepared filter paper. • The as-prepared filter paper has good recyclability and durability. • The method is easy, low cost and can be industrialized. - Abstract: A method for manufacturing durable superhydrophobic and superoleophilic filter paper for oil–water separation was developed via colloidal deposition. A porous film composed of PTFE nanoparticles was formed on filter paper, which was superhydrophobic with a water contact angle of 155.5° and superoleophilic with an oil contact angle of 0°. The obtained filter paper could separate a series of oil–water mixtures effectively with high separation efficiencies over 99%. Besides, the as-prepared filter paper kept stable superhydrophobicity and high separation efficiency even after 30 cycle times and could also work well under harsh environmental conditions like strong acidic or alkaline solutions, high temperature and ultraviolet irradiation. Compared with other approaches for fabricating oil–water materials, this approach is able to fabricate full-scale durable and practical oil–water materials easily and economically. The as-prepared filter paper is a promising candidate for oil–water separation

The conjunction of factors that lead to formation of giant gold provinces and deposits in non-arc settings

Science.gov (United States)

Groves, David I.; Goldfarb, Richard J.; Santosh, M.

2016-01-01

It is quite evident that it is not anomalous metal transport, nor unique depositional conditions, nor any single factor at the deposit scale, that dictates whether a mineral deposit becomes a giant or not. A hierarchical approach thus is required to progressively examine controlling parameters at successively decreasing scales in the total mineral system to understand the location of giant gold deposits in non-arc environments. For giant orogenic, intrusion-related gold systems (IRGS) and Carlin-type gold deposits and iron oxide-copper-gold (IOCG) deposits, there are common factors among all of these at the lithospheric to crustal scale. All are sited in giant gold provinces controlled by complex fundamental fault or shear zones that follow craton margins or, in the case of most Phanerozoic orogenic giants, define the primary suture zones between tectonic terranes. Giant provinces of IRGS, IOCG, and Carlin-type deposits require melting of metasomatized lithosphere beneath craton margins with ascent of hybrid lamprophyric to granitic magmas and associated heat flux to generate the giant province. The IRGS and IOCG deposits require direct exsolution of volatile-rich magmatic-hydrothermal fluids, whereas the association of such melts with Carlin-type ores is more indirect and enigmatic. Giant orogenic gold provinces show no direct relationship to such magmatism, forming from metamorphic fluids, but show an indirect relationship to lamprophyres that reflect the mantle connectivity of controlling first-order structures.

Automatic production of fullerenes by a JxB arc jet discharge

International Nuclear Information System (INIS)

Mieno, Tetsu

1995-01-01

Effective production of many kinds of fullerenes including higher fullerenes and endohedral metallo-fullerenes are necessary to advance fullerene science and technology. Currently, the DC arc discharge method is the most effective method to produce fullerenes. However, carbon atoms evaporated from the anode tend to deposit on the cathode, which grow towards the anode, and obstruct the control of the arc discharge. Furthermore, deposited carbon should be removed to maintain continuous fullerene production. Here, to reduce the deposition of carbon on the cathode, a new discharge method is introduced and the experiment performed. When steady magnetic field is applied perpendicular to the DC current of the arc, ions and electrons are accelerated by JxB force as a plasma jet in the vertical direction. This plasma flow also accelerates helium convection due to the viscosity effect. Therefore, the carbon atoms and carbon neutrals are both blown up by the arc jet before arriving at the cathode. The arc flame in the experiment is actually observed to extend upwards, which dearly indicates the effect of the JxB force

Carbon deposition using an expanding cascaded arc d.c. plasma

NARCIS (Netherlands)

Beulens, J.J.; Buuron, A.J.M.; Schram, D.C.

1991-01-01

In this work a strongly flowing cascaded arc burning on an argon-hydrogen mixture is used to dissociate and ionize hydrocarbons which are injected inside a nozzle which is mounted in the anode of the arc. The thermal plasma (T ˜ 10 000 K, p ˜ 0.5 bar) will then expand supersonically into a vessel

Native gold and gold-rich sulfide deposits in a submarine basaltic caldera, Higashi-Aogashima hydrothermal field, Izu-Ogasawara frontal arc, Japan

Science.gov (United States)

Iizasa, Kokichi; Asada, Akira; Mizuno, Katsunori; Katase, Fuyuki; Lee, Sangkyun; Kojima, Mitsuhiro; Ogawa, Nobuhiro

2018-04-01

Sulfide deposits with extremely high Au concentrations (up to 275 ppm; avg. 102 ppm, n = 15), high Au/Ag ratios (0.24, n = 15), and low Cu/(Cu + Zn) ratios (0.03, n = 15) were discovered in 2015 in active hydrothermal fields at a water depth of 760 m in a basalt-dominated submarine caldera in the Izu-Ogasawara frontal arc, Japan. Native gold grains occur in massive sulfide fragments, concretions, and metalliferous sediments from a sulfide mound (40 m across and 20 m high) with up to 30-m-high black smoker chimneys. Tiny native gold grains up to 14 μm in diameter are mainly present in sulfide fallouts from chimney orifices and plumes. Larger native gold grains up to 150 μm long occur mostly as discrete particles and/or with amorphous silica and sulfides. The larger gold grains are interpreted to represent direct precipitation from Au-bearing hydrothermal fluids circulating in and/or beneath the unconsolidated sulfide mound deposits. Sulfur isotope compositions from a limited number of sulfide separates (n = 4) range from 4.3 to 5.8‰ δ34S, similar to the quaternary volcanic rocks of the arc. Barite separates have values of 22.2 and 23.1‰, close to modern seawater values, and indicate probable seawater sulfate origin. The Cu, Zn, and Pb concentrations in bulk samples of sulfide-rich rocks are similar to those of volcanogenic massive sulfides formed in continental crustal environments. The gold is interpreted to have formed by low-temperature hydrothermal activity, perhaps genetically different from systems with documented magmatic contributions or from seafloor hydrothermal systems in other island arc settings. Its presence suggests that basalt-dominated submarine calderas situated on relatively thick continental crust in an intraoceanic arc setting such as the Higashi-Aogashima knoll caldera may be perspective for gold mineralization.

Characterization of n and p-type ZnO thin films grown by pulsed filtered cathodic vacuum arc system

International Nuclear Information System (INIS)

Kavak, H.; Erdogan, E.N.; Ozsahin, I.; Esen, R.

2010-01-01

Full text : Semiconductor ZnO thin films with wide band gap attract much interest due to their properties such as chemical stability in hydrogen plasma, high optical transparency in the visible and nearinfrared region. Due to these properties ZnO oxide is a promising materials for electronic or optoelectronic applications such as solar cell (as an antireflecting coating and a transparent conducting material), gas sensors, surface acoustic wave devices. The purpose of this research is to improve the properties of n and p-type ZnO thin films for device applications. Polycrystalline ZnO is naturally n-type and very difficult to dope to make p-type. Therefore nowadays hardly produced p-type ZnO attracts a lot of attention. Nitrogen considered as the best dopant for p-type ZnO thin films.The transparent, conductive and very precise thickness controlled n and p-type semiconducting nanocrystalline ZnO thin films were prepared by pulsed filtered cathodic vacuum arc deposition (PFCVAD) method. Structural, optical and electrical properties of these films were investigated. And also photoluminescence properties of these films were investigated. Transparent p-type ZnO thin films were produced by oxidation of PFCVAD deposited zinc nitride. Zinc nitride thin films were deposited with various thicknesses and under different oxygen pressures on glass substrates. Zinc nitride thin films, which were deposited at room temperatures, were amorphous and the optical transmission was below 70%. For oxidation zinc nitride, the sample was annealed in air starting from 350 degrees Celsium up to 550 degrees Celsium for one hour duration. These XRD patterns imply that zinc nitride thin films converted to zinc oxide thin films with the same hexagonal crystalline structures of ZnO. The optical measurements were made for each annealing temperature and the optical transmissions of ZnO thin films were found better than 90 percent in visible range after annealing over 350 degrees Celsium. By

Characterization of diamond-like carbon coatings prepared by pulsed bias cathodic vacuum arc deposition

International Nuclear Information System (INIS)

Wu Jinbao; Chang, J.-J.; Li, M.-Y.; Leu, M.-S.; Li, A.-K.

2007-01-01

Hydrogen free diamond-like carbon (DLC) coatings have been deposited on Si(100) and stainless steel substrates by cathodic vacuum arc plasma deposition with pulse voltage. Adherent deposits on silicon can be obtained through applying gradient Ti/TiC/DLC layers. A pulse bias of - 100 V was applied to the substrate in order to obtain a denser structure of DLC coating approximately 1 μm thick. The microstructure and hardness value of DLC films were analyzed by using X-ray photoelectron spectroscopy and nano-indenter. The experimental results show that the duty cycle strongly influenced the hardness and sp 3 content of the DLC coatings. We observed that when the duty cycle was raised from 2.5% to 12.5%, the hardness increased from 26 GPa to 49 GPa, and the sp 3 fraction of the DLC films measured by XPS increased from 39% to 50.8 % as well. But at constant duty cycle, say 12.5%, the hardness is dropped from 49 to 14 GPa in proportion to the increase of residual gas pressure from 3 x 10 -3 Pa to 1 Pa. As the residual gas pressure increased, collisional phenomenon will decrease the energy of the ions. Ions with low energy make more graphitic carbon links and result in a low hardness value

Variation in forearc basin development along the Sunda Arc, Indonesia

Science.gov (United States)

van der Werff, W.

The present forearc basin configuration along the Sunda Arc initially appears to have been controlled by extension and differential subsidence of basement blocks in response to the late Eocene collision of India with Asia. The late Oligocene increase in convergence between the South-east Asian and Indian Plates associated with a new pulse of subduction, resulted in basement uplift and the formation of a regional unconformity that can be recognized along the entire Sunda Arc. From the early to late Miocene, the Sumba and Savu forearc sectors along the eastern Sunda Arc may have been characterized by forearc extension. Submarine fan deposition on the arcward side of the evolving accretionary prism represents the first phase in forearc basin deposition. These fans were subsequently covered by basin and slope sediments derived from the evolving magmatic arc. Structural response to increased late Miocene compression varied along strike of the Sunda Arc. North of Bali, Lombok and Sumbawa, the incipient collision between Australia and the western Banda Arc caused back-arc thrusting and basin inversion. Towards the south of Java, an increase in both the size of the accretionary prism and convergence rates resulted in uplift and large scale folding of the outer forearc basin strata. Along the west coast of Sumatra, increased compression resulted in uplift along the inner side of the forearc along older transcurrent faults. Uplift of West Sumatra was followed by the deposition of a westward prograding sequence of terrigenous sediments that resulted in the development of a broad shelf. Initial forearc basin subsidence relates to the age of the subducting oceanic lithosphere, on top of which the basin is situated. Along the western Sunda Arc, both fexural loading of the evolving accretionary prism, and across arc strike-slip faulting represent additional factors that result in forearc subsidence.

Optical arc sensor using energy harvesting power source

Energy Technology Data Exchange (ETDEWEB)

Choi, Kyoo Nam, E-mail: knchoi@inu.ac.kr; Rho, Hee Hyuk, E-mail: rdoubleh0902@inu.ac.kr [Dept. of Information and Telecommunication Engineering Incheon National University Incheon 22012 (Korea, Republic of)

2016-06-03

Wireless sensors without external power supply gained considerable attention due to convenience both in installation and operation. Optical arc detecting sensor equipping with self sustaining power supply using energy harvesting method was investigated. Continuous energy harvesting method was attempted using thermoelectric generator to supply standby power in micro ampere scale and operating power in mA scale. Peltier module with heat-sink was used for high efficiency electricity generator. Optical arc detecting sensor with hybrid filter showed insensitivity to fluorescent and incandescent lamps under simulated distribution panel condition. Signal processing using integrating function showed selective arc discharge detection capability to different arc energy levels, with a resolution below 17 J energy difference, unaffected by bursting arc waveform. The sensor showed possibility for application to arc discharge detecting sensor in power distribution panel. Also experiment with proposed continuous energy harvesting method using thermoelectric power showed possibility as a self sustainable power source of remote sensor.

Optical arc sensor using energy harvesting power source

Science.gov (United States)

Choi, Kyoo Nam; Rho, Hee Hyuk

2016-06-01

Wireless sensors without external power supply gained considerable attention due to convenience both in installation and operation. Optical arc detecting sensor equipping with self sustaining power supply using energy harvesting method was investigated. Continuous energy harvesting method was attempted using thermoelectric generator to supply standby power in micro ampere scale and operating power in mA scale. Peltier module with heat-sink was used for high efficiency electricity generator. Optical arc detecting sensor with hybrid filter showed insensitivity to fluorescent and incandescent lamps under simulated distribution panel condition. Signal processing using integrating function showed selective arc discharge detection capability to different arc energy levels, with a resolution below 17J energy difference, unaffected by bursting arc waveform. The sensor showed possibility for application to arc discharge detecting sensor in power distribution panel. Also experiment with proposed continuous energy harvesting method using thermoelectric power showed possibility as a self sustainable power source of remote sensor.

Proceedings of the workshop on vacuum arc ion sources

International Nuclear Information System (INIS)

Brown, I.

1996-08-01

Topics included in the papers presented at this conference are: vacuum arc ion source development at GSI (Gesellschaft fuer Schwerionenforschung, Germany), ITEP (Institute for Theoretical and Experimental Physics, Russia), Lawrence Berkeley Laboratory, and ANSTO (Australian Nuclear Science and Technology Organization); triggers for vacuum arc sources; plasma distribution of cathodic arc deposition system; high ion charge states in vacuum arc ion sources; and gas and metal ion sources. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database

Design of arc power supply for neutral beam injection system based on super capacitor energy storage

International Nuclear Information System (INIS)

Yang Puqiong; Xuan Weimin; Cao Jianyong; Li Qing; Liu Xiaolong

2015-01-01

The arc power supply is one of the most important equipment for neutral beam injection system. The stability of arc discharge and the quality of ion beam extraction were determined by its performance. For improving stability of the arc discharge, reducing the power network capacity and decreasing impulse on power network, the topology of the arc power supply applied the structure of DC/DC converter based on technology of super capacitor energy storage and switching power supply. Several IGBT power modules are operated in parallel, and it can improve the arc power supply's operating frequency and dynamic response. A filter circuit and a current fast transferring circuit were designed based on a detailed analysis on working process of the arc power sup- ply. According to the requirements and parameters of the arc power supply, and the current response of RL first order circuit, the minimum filter inductances were accurately calculated. Finally, using the model and Matlab, the performance of the arc power supply was simulated and verified, and it meets the design requirement. (authors)

IODP Expedition 351 Izu-Bonin-Mariana Arc Origins: Preliminary Results

Science.gov (United States)

Ishizuka, O.; Arculus, R. J.; Bogus, K.

2014-12-01

Understanding how subduction zones initiate and continental crust forms in intraoceanic arcs requires knowledge of the inception and evolution of a representative intraoceanic arc, such as the Izu-Bonin-Mariana (IBM) Arc system. This can be obtained by exploring regions adjacent to an arc, where unequivocal pre-arc crust overlain by undisturbed arc-derived materials exists. IODP Exp. 351 (June-July 2014) specifically targeted evidence for the earliest evolution of the IBM system following inception. Site U1438 (4711 m water depth) is located in the Amami Sankaku Basin (ASB), west of the Kyushu-Palau Ridge (KPR), a paleo-IBM arc. Primary objectives of Exp. 351 were: 1) determine the nature of the crust and mantle pre-existing the IBM arc; 2) identify and model the process of subduction initiation and initial arc crust formation; 3) determine the compositional evolution of the IBM arc during the Paleogene; 4) establish geophysical properties of the ASB. Seismic reflection profiles indicate a ~1.3 km thick sediment layer overlying ~5.5 km thick igneous crust, presumed to be oceanic. This igneous crust seemed likely to be the basement of the IBM arc. Four holes were cored at Site U1438 spanning the entire sediment section and into basement. The cored interval comprises 5 units: uppermost Unit I is hemipelagic sediment with intercalated ash layers, presumably recording explosive volcanism mainly from the Ryukyu and Kyushu arcs; Units II and III host a series of volcaniclastic gravity-flow deposits, likely recording the magmatic history of the IBM Arc from arc initiation until 25 Ma; Siliceous pelagic sediment (Unit IV) underlies these deposits with minimal coarse-grained sediment input and may pre-date arc initiation. Sediment-basement contact occurs at 1461 mbsf. A basaltic lava flow section dominantly composed of plagioclase and clinopyroxene with rare chilled margins continues to the bottom of the Site (1611 mbsf). The expedition successfully recovered pre-IBM Arc

Effect of Coating Thickness on the Properties of TiN Coatings Deposited on Tool Steels Using Cathodic Arc Pvd Technique

Science.gov (United States)

Mubarak, A.; Akhter, Parvez; Hamzah, Esah; Mohd Toff, Mohd Radzi Hj.; Qazi, Ishtiaq A.

Titanium nitride (TiN) widely used as hard coating material, was coated on tool steels, namely on high-speed steel (HSS) and D2 tool steel by physical vapor deposition method. The study concentrated on cathodic arc physical vapor deposition (CAPVD), a technique used for the deposition of hard coatings for tooling applications, and which has many advantages. The main drawback of this technique, however, is the formation of macrodroplets (MDs) during deposition, resulting in films with rougher morphology. Various standard characterization techniques and equipment, such as electron microscopy, atomic force microscopy, hardness testing machine, scratch tester, and pin-on-disc machine, were used to analyze and quantify the following properties and parameters: surface morphology, thickness, hardness, adhesion, and coefficient of friction (COF) of the deposited coatings. Surface morphology revealed that the MDs produced during the etching stage, protruded through the TiN film, resulting in film with deteriorated surface features. Both coating thickness and indentation loads influenced the hardness of the deposited coatings. The coatings deposited on HSS exhibit better adhesion compared to those on D2 tool steel. Standard deviation indicates that the coating deposited with thickness around 6.7 μm showed the most stable trend of COF versus sliding distance.

Maintaining Arc Consistency in Non-Binary Dynamic CSPs using Simple Tabular Reduction

DEFF Research Database (Denmark)

Queva, Matthieu Stéphane Benoit; Probst, Christian W.; Ricci, Laurent

2010-01-01

CSPs use filtering techniques such as arc consistency, which also have been adapted to handle DCSPs with binary constraints. However, there exists only one algorithm targeting non-binary DCSPs (DnGAC4). In this paper we present a new algorithm DnSTR for maintaining arc consistency in DCSPs with non-binary...

Arc generation from sputtering plasma-dielectric inclusion interactions

CERN Document Server

Wickersham, C E J; Fan, J S

2002-01-01

Arcing during sputter deposition and etching is a significant cause of particle defect generation during device fabrication. In this article we report on the effect of aluminum oxide inclusion size, shape, and orientation on the propensity for arcing during sputtering of aluminum targets. The size, shape, and orientation of a dielectric inclusion plays a major role in determining the propensity for arcing and macroparticle emission. In previous studies we found that there is a critical inclusion size required for arcing to occur. In this article we used high-speed videos, electric arc detection, and measurements of particle defect density on wafers to study the effect of Al sub 2 O sub 3 inclusion size, shape, and orientation on arc rate, intensity, and silicon wafer particle defect density. We found that the cross-sectional area of the inclusion exposed to the sputtering plasma is the critical parameter that determines the arc rate and rate of macroparticle emission. Analysis of the arc rate, particle defect...

Gold nanoparticle formation in diamond-like carbon using two different methods: Gold ion implantation and co-deposition of gold and carbon

International Nuclear Information System (INIS)

Salvadori, M. C.; Teixeira, F. S.; Araújo, W. W. R.; Sgubin, L. G.; Cattani, M.; Spirin, R. E.; Brown, I. G.

2012-01-01

We describe work in which gold nanoparticles were formed in diamond-like carbon (DLC), thereby generating a Au-DLC nanocomposite. A high-quality, hydrogen-free DLC thin film was formed by filtered vacuum arc plasma deposition, into which gold nanoparticles were introduced using two different methods. The first method was gold ion implantation into the DLC film at a number of decreasing ion energies, distributing the gold over a controllable depth range within the DLC. The second method was co-deposition of gold and carbon, using two separate vacuum arc plasma guns with suitably interleaved repetitive pulsing. Transmission electron microscope images show that the size of the gold nanoparticles obtained by ion implantation is 3-5 nm. For the Au-DLC composite obtained by co-deposition, there were two different nanoparticle sizes, most about 2 nm with some 6-7 nm. Raman spectroscopy indicates that the implanted sample contains a smaller fraction of sp 3 bonding for the DLC, demonstrating that some sp 3 bonds are destroyed by the gold implantation.

Synthesis of graphene-like transparent conductive films on dielectric substrates using a modified filtered vacuum arc system

Energy Technology Data Exchange (ETDEWEB)

Lux, Helge, E-mail: lux@th-wildau.de; Schrader, Sigurd [Technical University of Applied Sciences Wildau, Hochschulring 1, Wildau 15745 (Germany); Siemroth, Peter [Arc Precision GmbH, Schwartzkopffstraße 2, Wildau 15745 (Germany); Sgarlata, Anna [Department of Physics, University of Roma - Tor Vergata, Via della Ricerca Scientifica 1, Roma 00133 (Italy); Prosposito, Paolo; Casalboni, Mauro [Department of Industrial Engineering, University of Roma - Tor Vergata, and Italian Interuniversity Consortium on Materials Science and Technology (INSTM), Research Unit Roma Tor Vergata Via del Politecnico 1, Roma 00133 (Italy); Schubert, Markus Andreas [IHP Innovations for High Performance Microelectronics, Im Technologiepark 25, Frankfurt (Oder) 15236 (Germany)

2015-05-21

Here, we present a reliable process to deposit transparent conductive films on silicon oxide, quartz, and sapphire using a solid carbon source. This layer consists of partially ordered graphene flakes with a lateral dimension of about 5 nm. The process does not require any catalytic metal and exploits a high current arc evaporation (Φ-HCA) to homogeneously deposit a layer of carbon on heated substrates. A gas atmosphere consisting of Argon or Argon/Hydrogen blend acting as a buffer influences the morphology of the growing film. scanning tunneling microscopy, transmission electron microscopy, and Raman spectra were used for a thorough characterization of the samples in order to optimize the growth parameters. The best carbon layers have a surface resistance of 5.7 × 10{sup 3} Ω{sub ◻} whereas the optical transparency of the coatings is 88% with an excellent homogeneity over areas of several cm{sup 2}. Such results are compatible with most semiconductor fabrication processes and make this method very promising for various industrial applications.

The Electron-Cloud Effect in the Arcs of the LHC

CERN Document Server

Furman, M A

1998-01-01

We present an update of our estimates for the power deposition arising from the electron-cloud effect in the dipole bending magnets in the arcs of the LHC. In addition, we present the estimate of the power deposition in the field-free regions in the arcs. We hold the number of particles per bunch and the bunch spacing fixed at their nominal values, and we assume throughout a high photon reflectivi ty. We explore the dependence of the power deposition on the photoelectric efficiency and on secondary emission yield parameters. We find a marked sensitivity to parameters that characterize secondary emission on the scale of 5 - 10 eV.

Back-arc with frontal-arc component origin of Triassic Karmutsen basalt, British Columbia, Canada

Science.gov (United States)

Barker, F.; Sutherland, Brown A.; Budahn, J.R.; Plafker, G.

1989-01-01

The largely basaltic, ???4.5-6.2-km-thick, Middle to Upper Triassic Karmutsen Formation is a prominent part of the Wrangellian sequence. Twelve analyses of major and minor elements of representative samples of pillowed and massive basalt flows and sills from Queen Charlotte and Vancouver Islands are ferrotholeiites that show a range of 10.2-3.8% MgO (as normalized, H2O- and CO2-free) and related increases in TiO2 (1.0-2.5%), Zr (43-147 ppm) and Nb (5-16 ppm). Other elemental abundances are not related simply to MgO: distinct groupings are evident in Al2O3, Na2O and Cr, but considerable scatter is present in FeO* (FeO + 0.9Fe2O3) and CaO. Some of the variation is attributed to alteration during low-rank metamorphism or by seawater - including variation of Ba, Rb, Sr and Cu, but high-field-strength elements (Sc, Ti, Y, Zr and Nb) as well as Cr, Ni, Cu and rare-earth elements (REE's) were relatively immobile. REE's show chondrite-normalized patterns ranging from light-REE depleted to moderately light-REE enriched. On eleven discriminant plots these analyses fall largely into or across fields of within-plate basalt (WIP), normal or enriched mid-ocean-ridge tholeiite (MORB) and island-arc tholeiite (IAT). Karmutsen basalts are chemically identical to the stratigraphically equivalent Nikolai Greenstone of southern Alaska and Yukon Territory. These data and the fact that the Karmutsen rests on Sicker Group island-arc rocks of Paleozoic age suggest to us that: 1. (1) the basal arc, after minor carbonate-shale deposition, underwent near-axial back-arc rifting (as, e.g., the Mariana arc rifted at different times); 2. (2) the Karmutsen basalts were erupted along this rift or basin as "arc-rift" tholeiitite; and 3. (3) after subsequent deposition of carbonates and other rocks, and Jurassic magmatism, a large fragment of this basalt-sediment-covered island arc was accreted to North America as Wrangellia. The major- and minor-elemental abundances of Karmutsen basalt is modeled

TIG Wire and Arc Additive Manufacturing of 5A06 Aluminum Alloy

Directory of Open Access Journals (Sweden)

HUANG Dan

2017-03-01

Full Text Available Wire and arc additive manufacturing(WAAM was investigated by tungsten inert gas arc welding method(TIG, in which φ1.2mm filler wire of aluminum alloy 5A06(Al-6Mg-Mn-Si was selected as deposition metal. The prototyping process was conducted by a TIG power source(working in AC mode manipulated by a four-axis linkage CNC machine. Backplate preheating temperature and arc current on deposited morphologies of single layer and multi-layer were researched. The microstructure was observed and the sample tensile strength was tested. For single layer, a criterion that describes the correlation between backplate preheating temperature and arc peak current, of which both contribute to the smoothening of the deposited layer. The results show that the layer height drops sharply from the first layer of 3.4mm and keeps at 1.7mm after the 8th layer. Fine dendrite grain and equiaxed grain are found inside a layer and coarsest columnar dendrite structure at layer boundary zone; whereas the microstructure of top region of the deposited sample changes from fine dendrite grain to equiaxed grain that turns to be the finest structure. Mechanical property of the deposited sample is isotropic, in which the tensile strength is approximately 295MPa with the elongation around 36%.

Temperature dependence of the residual stresses and mechanical properties in TiN/CrN nano-layered coatings processed by cathodic arc deposition

International Nuclear Information System (INIS)

Lomello, F.; Arab Pour Yazdi; Sanchette, F.; Schuster, F.; Tabarant, M.; Billard, A.

2014-01-01

Nano-layered TiN-CrN coatings were synthesized by cathodic arc deposition (CAD) on M2 tool steel substrates. The aim of this study was to establish a double-correlation between the influence of the bilayer period and the deposition temperature on the resulting mechanical-tribological properties. The superlattice hardening enhancement was observed in samples deposited at different temperatures - i.e. without additional heating, 300 C and 400 C. Nonetheless, the residual compressive stresses are believed to be the responsible for reducing the hardness enhancement when the deposition temperature was increased. For instance, sample deposited without additional heating presented a hardness of 48.5 ± 1.3 GPa, while by increasing the processing temperature up to 400 C it was reduced down to 31.2 ± 4.1 GPa due to the stress relaxation. Indeed, the sample deposited at low temperature which possesses the thinnest bilayer period (13 nm) exhibited better mechanical properties. On the contrary, the role of the interfaces introduced when the period is decreased seems to rule the wear resistance. (authors)

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.

properties of Cr(C,N) hard coatings deposited in Ar-C2H2-N2 plasma

International Nuclear Information System (INIS)

Macek, M.; Cekada, M.; Kek, D.; Panjan, P.

2002-01-01

Mechanical properties, microstructure and the average chemical composition of Cr(C,N) hard coatings deposited in Ar-C 2 H 2 -N 2 plasma strongly depends on the partial pressure of the reactive gases (N 2 , C 2 H 2 ) and on the type of the deposition equipment. In this study we report on the properties of Cr(C,N) hard coatings deposited by means of the triode ion plating in the BAI 730 apparatus and those prepared by sputter deposition in Balzers Sputron in the pressure range from 0.12 Pa (pure Ar) up to 0.35 Pa with different ratios (0-100%) between C 2 H 2 and N 2 . At first mechanical properties (microhardness and adhesion) of coatings were analyzed on the common way. Internal stress was measured by the radius of substrate curvature. Chemical composition of coatings was analyzed by means of AES while the Raman and XPS spectroscopy was used to determined the nature of carbon bonding in the Cr(C,N) films. Microstructure was determined by XRD as well as by means of TEM and TED. Chemical state of various elements in the coating has been studied by XPS. The ratio of the carbide bond (C-Cr) against the C-C and C-H bonds was calculated. The existence of the graphite phase in some Cr(C,N) coatings was confirmed by Raman spectroscopy. (Authors)

Evaluating optical hazards from plasma arc cutting.

Science.gov (United States)

Glassford, Eric; Burr, Gregory

2018-01-01

The Health Hazard Evaluation Program of the National Institute for Occupational Safety and Health evaluated a steel building materials manufacturer. The employer requested the evaluation because of concerns about optical radiation hazards from a plasma arc cutting system and the need to clarify eye protection requirements for plasma operators, other employees, and visitors. The strength of the ultraviolet radiation, visible radiation (light), and infrared radiation generated by the plasma arc cutter was measured at various distances from the source and at different operating amperages. Investigators also observed employees performing the plasma arc cutting. Optical radiation above safe levels for the unprotected eyes in the ultraviolet-C, ultraviolet-B, and visible light ranges were found during plasma arc cutting. In contrast, infrared and ultraviolet-A radiation levels during plasma arc cutting were similar to background levels. The highest non-ionizing radiation exposures occurred when no welding curtains were used. A plasma arc welding curtain in place did not eliminate optical radiation hazards to the plasma arc operator or to nearby employees. In most instances, the measured intensities for visible light, UV-C, and UV-B resulted in welding shade lens numbers that were lower than those stipulated in the OSHA Filter Lenses for Protection Against Radiant Energy table in 29 CFR 1910.133(a)(5). [1] Investigators recommended using a welding curtain that enclosed the plasma arc, posting optical radiation warning signs in the plasma arc cutter area, installing audible or visual warning cues when the plasma arc cutter was operating, and using welding shades that covered the plasma arc cutter operator's face to protect skin from ultraviolet radiation hazards.

Vacuum arc plasma deposition of thin titanium dioxide films on silicone elastomer as a functional coating for medical applications.

Science.gov (United States)

Boudot, Cécile; Kühn, Marvin; Kühn-Kauffeldt, Marina; Schein, Jochen

2017-05-01

Silicone elastomer is a promising material for medical applications and is widely used for implants with blood and tissue contact. However, its strong hydrophobicity limits adhesion of tissue cells to silicone surfaces, which can impair the healing process. To improve the biological properties of silicone, a triggerless pulsed vacuum cathodic arc plasma deposition technique was applied to deposit titanium dioxide (TiO 2 ) films onto the surface. Scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and contact angle measurements were used for coating characterization. Deposited films were about 150nm thick and exhibited good adhesion to the underlying silicone substrate. Surface wettability and roughness both increased after deposition of the TiO 2 layer. In addition, cell-biological investigations demonstrated that the in-vitro cytocompatibility of TiO 2 -coated samples was greatly improved without impacting silicone's nontoxicity. For validation of use in medical devices, further investigations were conducted and demonstrated stability of surface properties in an aqueous environment for a period of 68days and the coating's resistance to several sterilization methods. Copyright © 2016 Elsevier B.V. All rights reserved.

Investigations Of A Pulsed Cathodic Vacuum Arc

Science.gov (United States)

Oates, T. W. H.; Pigott, J.; Denniss, P.; Mckenzie, D. R.; Bilek, M. M. M.

2003-06-01

Cathodic vacuum arcs are well established as a method for producing thin films for coatings and as a source of metal ions. Research into DC vacuum arcs has been going on for over ten years in the School of Physics at the University of Sydney. Recently a project was undertaken in the school to design and build a pulsed CVA for use in the investigation of plasma sheaths and plasma immersion ion implantation. Pulsed cathodic vacuum arcs generally have a higher current and plasma density and also provide a more stable and reproducible plasma density than their DC counterparts. Additionally it has been shown that if a high repetition frequency can be established the deposition rate of pulsed arcs is equal to or greater than that of DC arcs with a concomitant reduction in the rate of macro-particle formation. We present here results of our investigations into the building of a center-triggered pulsed cathodic vacuum arc. The design of the power supply and trigger mechanism and the geometry of the anode and cathode are examined. Observations of type I and II arc spots using a CCD camera, and cathode spot velocity dependence on arc current will be presented. The role of retrograde motion in a high current pulsed arc is discussed.

Investigations Of A Pulsed Cathodic Vacuum Arc

International Nuclear Information System (INIS)

Oates, T.W.H.; Pigott, J.; Denniss, P.; Mckenzie, D.R.; Bilek, M.M.M.

2003-01-01

Cathodic vacuum arcs are well established as a method for producing thin films for coatings and as a source of metal ions. Research into DC vacuum arcs has been going on for over ten years in the School of Physics at the University of Sydney. Recently a project was undertaken in the school to design and build a pulsed CVA for use in the investigation of plasma sheaths and plasma immersion ion implantation. Pulsed cathodic vacuum arcs generally have a higher current and plasma density and also provide a more stable and reproducible plasma density than their DC counterparts. Additionally it has been shown that if a high repetition frequency can be established the deposition rate of pulsed arcs is equal to or greater than that of DC arcs with a concomitant reduction in the rate of macro-particle formation. We present here results of our investigations into the building of a center-triggered pulsed cathodic vacuum arc. The design of the power supply and trigger mechanism and the geometry of the anode and cathode are examined. Observations of type I and II arc spots using a CCD camera, and cathode spot velocity dependence on arc current will be presented. The role of retrograde motion in a high current pulsed arc is discussed

Osteoblast Adhesion on Cathodic Arc Plasma Deposited Nano-Multilayered TiCrAlSiN Thin Films

Energy Technology Data Exchange (ETDEWEB)

Kim, Sun Kyu [University of Ulsan, Ulsan (Korea, Republic of); Pham, Vuong Hung [Hanoi University of Science and Technology (HUST), Hanoi (Viet Nam)

2014-03-15

Adhesion of osteoblast cells to TiCrAlSiN thin films was evaluated in vitro. Ti and TiCrAlSiN thin films were deposited on glass substrates by cathodic arc deposition. Surface roughness and chemistry of the TiCrAlSiN thin films was characterized by AFM and EPMA, respectively. Ti and TiCrAlSiN thin films and glass coverslips were cultured with human osteoblast cells (hFOB 1.19). The cell cytoskeleton was analyzed by observing the organization of actin stress fibers and microtubules. Cell proliferation was investigated by MTT assay and visualization. Focal contact adhesion was studied by observing the vinculin density. The results indicated that the TiCrAlSiN coating significantly influenced the actin cytoskeleton and microtubule organization. Human osteoblasts hFOB attached and proliferated better on TiCrAlSiN thin films with more focal contact adhesions than on Ti thin films or glass surfaces. These results suggest that TiCrAlSiN thin films can be an implantable material where the maximum cell adhesion is required.

Functional Blocks and Biquadratic ARC Filters using Transimpedance Amplifiers

Directory of Open Access Journals (Sweden)

R. Sarman

1997-04-01

Full Text Available The aims of the article are design and analysis of modern circuits including high performance functional blocks and biquadratic filters using transimpedance amplifiers. Here are given various types of these circuits, that works in classical voltage, current or hybrid mode. In this paper are also compared various possibilities of connection of single amplifier filters as for reduction of influence of transimpedance amplifier parasitic elements.

Functional Blocks and Biquadratic ARC Filters using Transimpedance Amplifiers

OpenAIRE

R. Sarman; R. Prokop; T. Dostal

1997-01-01

The aims of the article are design and analysis of modern circuits including high performance functional blocks and biquadratic filters using transimpedance amplifiers. Here are given various types of these circuits, that works in classical voltage, current or hybrid mode. In this paper are also compared various possibilities of connection of single amplifier filters as for reduction of influence of transimpedance amplifier parasitic elements.

The vacuum-arc plasma motion in a toroidal magnetic field

International Nuclear Information System (INIS)

Timoshenko, A.I.; Gnybida, M.V.; Taran, V.S.; Tereshin, V.I.; Chechelnitskij, O.G.

2005-01-01

The separation of the vacuum-arc plasma from macro-particles in the curvilinear plasma filters allows obtaining coatings with especially high characteristics. However, inside such filters the significant plasma losses also have been occurred. At the same time, increasing in the filter's efficiency is a difficult task without an effective mathematical model that really would describe the vacuum-arc plasma motion in a toroidal magnetic field. The description based on the flax-tube model was in fact only the first approximation in the decision of this problem. According to detailed flax-tube analysis of ions passage through the quarter torus plasma guide, the efficiency of the filter should grow up to 85% as the positive potential U, applied to the body of the plasma guide, is on the increase. However, the experiment showed that maximum of transparency reach up to ∼ 12%, at potential about of +18 Volts, and comes down under the further increase in potential. Such big digression from experiment does not justify the use of flux-tube model for designing of curvilinear plasma filters. We offer the new approach to the description of the vacuum-arc plasma motion in a toroidal magnetic field based on the solutions of steady-state (∂/∂t=0) Vlasov-Maxwell equations for the long plasma column aligned parallel to a constant axial magnetic field. The relations for the self-consistent electric polarization fields, which appear due to displacement of the electron component from ionic one on the curvilinear part of motion, were derived within a framework of the drift approximation. The dynamics of the central part of the plasma flow in the electric polarization fields was considered in detail. The displacement of the plasma flow at the output of the plasma guide was calculated for the carbon and titanium plasmas. The good agreement with the experimental data was obtained. (author)

X-ray filter for x-ray powder diffraction

Science.gov (United States)

Sinsheimer, John Jay; Conley, Raymond P.; Bouet, Nathalie C. D.; Dooryhee, Eric; Ghose, Sanjit

2018-01-23

Technologies are described for apparatus, methods and systems effective for filtering. The filters may comprise a first plate. The first plate may include an x-ray absorbing material and walls defining first slits. The first slits may include arc shaped openings through the first plate. The walls of the first plate may be configured to absorb at least some of first x-rays when the first x-rays are incident on the x-ray absorbing material, and to output second x-rays. The filters may comprise a second plate spaced from the first plate. The second plate may include the x-ray absorbing material and walls defining second slits. The second slits may include arc shaped openings through the second plate. The walls of the second plate may be configured to absorb at least some of second x-rays and to output third x-rays.

Deposition and diagenesis of the Hibernia member, Jeanne d'Arc Basin, offshore Newfoundland

Energy Technology Data Exchange (ETDEWEB)

Fitzgerald, C E

1987-01-01

The Jeanne d'Arc Basin was formed during Late Triassic to Early Cretaceous time by two episodes of rifting that caused repeated movement on one set of basin-forming faults. This resulted in up to 14 km of sediments, some of which contain huge reserves of hydrocarbons. The Hibernia member, the subject of this thesis, is a sandstone dominated zone within this basin-fill that contains a high proportion of the discovered hydrocarbons. Deposition of the Hibernia member is a result of two simultaneous and related events during Tithonian to Berriasian time: deep erosion of upthrown sides of the fault blocks, and a global eustatic rise of sea level. The provenance and depositional environment are interpreted from the examination of cores, cuttings, microfossils, and thin sections. The siliciclastics were derived from a southern source of sediments and sedimentary rocks that had an original metamorphic origin. They were deposited in a non-marine to brackish water environment of channels and associated floodplains in an anastomosed fluvial system. Rates of sedimentation and subsidence were high, and coupled with a contemporaneous eustatic sea level rise resulted in rapid aggradation and a thick sequence. The center of the basin currently has the highest geothermal gradient and thinnest oil window. Burial and thermal history curves show that the source rocks reached maturity first at the Ben Nevis well; early-formed hydrocarbons may have been lost during tectonic movements in Albian time. The source rocks underlying the Hibernia field are presently at peak oil-generating capability. Organic acids formed during the maturation of organic matter have produced excellent secondary porosity in the sandstones of the Hibernia field. However, at Ben Nevis, subsequent thermal degradation of carboxylic acids allowed late-stage cementation by ferroan calcite cement, destroying the reservoir porosity. 63 refs., 79 figs., 1 tab

Improving the conductance of ZnO thin film doping with Ti by using a cathodic vacuum arc deposition process

International Nuclear Information System (INIS)

Wu, Chun-Sen; Lin, Bor-Tsuen; Jean, Ming-Der

2011-01-01

The Ti-doped ZnO films compared to un-doped ZnO films were deposited onto Corning XG glass substrates by using a cathodic vacuum arc deposition process in a mixture of oxygen and argon gases. The structural, electrical and optical properties of un-doped and Ti-doped ZnO films have been investigated. When the Ti target power is about 750 W, the incorporation of titanium atoms into zinc oxide films is obviously effective. Additionally, the resistivity of un-doped ZnO films is high and reduces to a value of 3.48 x 10 -3 Ω-cm when Ti is incorporated. The Ti doped in the ZnO films gave rise to the improvement of the conductivity of the films obviously. The Ti-doped ZnO films have > 85% transmittance in a range of 400-700 nm.

Influence of Plasma Jet Temperature Profiles in Arc Discharge Methods of Carbon Nanotubes Synthesis.

Science.gov (United States)

Raniszewski, Grzegorz; Wiak, Slawomir; Pietrzak, Lukasz; Szymanski, Lukasz; Kolacinski, Zbigniew

2017-02-23

One of the most common methods of carbon nanotubes (CNTs) synthesis is application of an electric-arc plasma. However, the final product in the form of cathode deposit is composed of carbon nanotubes and a variety of carbon impurities. An assay of carbon nanotubes produced in arc discharge systems available on the market shows that commercial cathode deposits contain about 10% CNTs. Given that the quality of the final product depends on carbon-plasma jet parameters, it is possible to increase the yield of the synthesis by plasma jet control. Most of the carbon nanotubes are multiwall carbon nanotubes (MWCNTs). It was observed that the addition of catalysts significantly changes the plasma composition, effective ionization potential, the arc channel conductance, and in effect temperature of the arc and carbon elements flux. This paper focuses on the influence of metal components on plasma-jet forming containing carbon nanotubes cathode deposit. The plasma jet temperature control system is presented.

Influence of Plasma Jet Temperature Profiles in Arc Discharge Methods of Carbon Nanotubes Synthesis

Directory of Open Access Journals (Sweden)

Grzegorz Raniszewski

2017-02-01

Full Text Available One of the most common methods of carbon nanotubes (CNTs synthesis is application of an electric-arc plasma. However, the final product in the form of cathode deposit is composed of carbon nanotubes and a variety of carbon impurities. An assay of carbon nanotubes produced in arc discharge systems available on the market shows that commercial cathode deposits contain about 10% CNTs. Given that the quality of the final product depends on carbon–plasma jet parameters, it is possible to increase the yield of the synthesis by plasma jet control. Most of the carbon nanotubes are multiwall carbon nanotubes (MWCNTs. It was observed that the addition of catalysts significantly changes the plasma composition, effective ionization potential, the arc channel conductance, and in effect temperature of the arc and carbon elements flux. This paper focuses on the influence of metal components on plasma-jet forming containing carbon nanotubes cathode deposit. The plasma jet temperature control system is presented.

The arc power supply for the TEXTOR neutral injectors

International Nuclear Information System (INIS)

Schwarz, U.; Pfister, U.; Goll, O.; Wurslin, R.; Scherer, J.; Haubmann, S.

1986-01-01

The 24 single arcs in the plasma source of the TEXTOR neutral injector are supplied with an overall current of 1800 A at an arc voltage of 150 V DC. The current is switched on and off in less than 1 msec. The paper presents a new modular solution for such a power supply. Each arc is powered by a separately switched mode supply module. One single module consists of a diode rectifier bridge with a filter, a fast semiconductor switch, an inductance in series for stabilizing the current and a free-wheeling path. The layout of this power supply system is described in detail based on test results. Design features and technical data are given

A 4 MV flattening filter-free beam: commissioning and application to conformal therapy and volumetric modulated arc therapy

International Nuclear Information System (INIS)

Stevens, S W; Rosser, K E; Bedford, J L

2011-01-01

Recent studies have indicated that radiotherapy treatments undertaken on a flattening filter-free (FFF) linear accelerator have a number of advantages over treatments undertaken on a conventional linear accelerator. In addition, 4 MV photon beams may give improved isodose coverage for some treatment volumes at air/tissue interfaces, compared to when utilizing the clinical standard of 6 MV photons. In order to investigate these benefits, FFF beams were established on an Elekta Beam Modulator linear accelerator for 4 MV photons. Commissioning beam data were obtained for open and wedged fields. The measured data were then imported into a treatment planning system and a beam model was commissioned. The beam model was optimized to improve dose calculations at shallow, clinically relevant depths. Following verification, the beam model was utilized in a treatment planning study, including volumetric modulated arc therapy, for a selection of lung, breast/chest wall and larynx patients. Increased dose rates of around 800 MU min -1 were recorded for open fields (relative to 320 MU min -1 for filtered open fields) and reduced head scatter was inferred from output factor measurements. Good agreement between planned and delivered dose was observed in verification of treatment plans. The planning study indicated that with a FFF beam, equivalent (and in some cases improved) isodose profiles could be achieved for small lung and larynx treatment volumes relative to 4 MV filtered treatments. Furthermore, FFF treatments with wedges could be replicated using open fields together with an 'effective wedge' technique and isocentre shift. Clinical feasibility of a FFF beam was therefore demonstrated, with beam modelling, treatment planning and verification being successfully accomplished.

Etching Effect of an Atmospheric DC Arc Plasmatron

International Nuclear Information System (INIS)

Chun, Se Min; Kim, Ji Hun; Kang, In Je; Lee, Heon Ju

2010-01-01

Thermal plasmas (especially arc plasma) were extensively industrialized, principally by aeronautic sector. Cold plasma technologies have been developed in the microelectronics but their vacuum equipment limits their implantation. Plasmas used in dry etching, thin film deposition and surface treatment for display or semiconductor industries are operating at low pressures in very costly due to the use of vacuum equipment and vacuum components. Use of DC arc plasmatrons in welding, soldering, and cutting of metals is well known. A DC-arc plasmatron with high durability was reported to be a suitable device for etching silicon and photo-resist surfaces

SU-E-T-493: Influence of Filtered and Flatting Filter Free Photon Beam of 10 Megavolts Energy On Rapid Arc Radiotherapy Planning for Cervix Carcinoma

Energy Technology Data Exchange (ETDEWEB)

Girigesh, Y; Kumar, L; Raman, K; Mishra, M [Rajiv Gandhi Cancer Institute and Research Centre, New Delhi, Delhi (India)

2015-06-15

Purpose: Aim of this study is to determine the dosimetric influence of Filtered and Flatting Filter Free Photon Beam of 10 MV energy on RA planning for Ca. Cervix. Methods: CT data sets of eleven patients reported with carcinoma cervix were used for RA planning for 10MV -FFB and 10MV-FFFB. RA plans were generated using two full arcs.All RA plans were generated to deliver a dose of 50.4Gy in 28 fractions for PTV and ALARA for OAR’s. All plans were analysed for PTV Coverage, conformity Index, homogeneity index, dose to OAR’s, integral dose to normal tissue and total monitor units were studied. Results: DVH was used to evaluate RA plans for both 10MV-FFB and 10MV-FFFB photon beam. Planning results show a comparable PTV coverage for both energies. Results shows volume of PTV receiving prescription dose were 95.10+ 0.09% and 95.09 +0.11%, and volume of PTV receiving a dose of 107% is 0.45+0.96% and 5.25+8.9%, homogeneity index (HI) were 1.051+0.007 and 1.066+0.008, Conformity Index(CI) were 1.003+0.019 and 1.012+0.013, Mean Integral dose were 2.65+0.34 and 2.60+0.33(*10−5Gy.cm3) for 10MV-FFB and 10MV-FFFB respectively. 10MV-FB shows statistically significant (p<0.05) improvement in mean doses to bladder, rectum, bowel and mean total number of MU’s and also shows remarkable decrease in mean total no. of MU’s by 43.7% in comparison to 10MV-FFFB. There is statistically significant (p<0.05) difference found in CI and HI for 10MV-FB in comparison to 10MV -FFF beam. 10MV-FFFB shows statistically significant (p<0.05) for mean NTID and delivers 1.65 % less NTID in comparison to 10 MV- FB. Conclusion: 10MV-FB is superior to 10MV-FFFB for rapid arc planning in case of Cervix carcinomas, it offers better target coverage and OAR’s sparing, comparable mean Integral dose to normal tissues and 10 MV- FB also produced highly conformal and homogeneous dose distribution in comparison to 10MV-FFFB.

Recent advances in vacuum arc ion sources

International Nuclear Information System (INIS)

Brown, I.G.; Anders, A.; Anders, S.; Dickinson, M.R.; MacGill, R.A.; Oks, E.M.

1995-07-01

Intense beams of metal ions can be formed from a vacuum arc ion source. Broadbeam extraction is convenient, and the time-averaged ion beam current delivered downstream can readily be in the tens of milliamperes range. The vacuum arc ion source has for these reasons found good application for metallurgical surface modification--it provides relatively simple and inexpensive access to high dose metal ion implantation. Several important source developments have been demonstrated recently, including very broad beam operation, macroparticle removal, charge state enhancement, and formation of gaseous beams. The authors have made a very broad beam source embodiment with beam formation electrodes 50 cm in diameter, producing a beam of width ∼35 cm for a nominal beam area of ∼1,000 cm 2 , and a pulsed Ti beam current of about 7 A was formed at a mean ion energy of ∼100 keV. Separately, they've developed high efficiency macroparticle-removing magnetic filters and incorporated such a filter into a vacuum arc ion source so as to form macroparticle-free ion beams. Jointly with researchers at the High Current Electronics Institute at Tomsk, Russia, and the Gesellschaft fuer Schwerionenforschung at Darmstadt, Germany, they've developed a compact technique for increasing the charge states of ions produced in the vacuum arc plasma and thus providing a simple means of increasing the ion energy at fixed extractor voltage. Finally, operation with mixed metal and gaseous ion species has been demonstrated. Here, they briefly review the operation of vacuum marc ion sources and the typical beam and implantation parameters that can be obtained, and describe these source advances and their bearing on metal ion implantation applications

Comparison of carbon stripper foils produced by ARC discharge and laser ablation

Energy Technology Data Exchange (ETDEWEB)

Ophel, T.R.; Rhode, A.; Lobanov, N.; Weisser, D.C.; Turkentine, R.; Wolf, B.; Wlliman, R.G. [Australian National Univ. Canberra, ACT (Australia). Research School of Physical Sciences and Engineering

1998-06-01

The present work describes a series of investigations which compared the arc-deposited foils, prepared at ANU with a batch of foils from Munich, prepared by laser-ablation. The two foil types were bombarded with a beam of 6.8 MeV of {sup 197}Au recording their behaviour and monitoring the total stripped current. Optical and electron spectroscopy was carried out and indicate that the arc-deposited foils were relatively amorphous and smooth, while the laser-ablated foils appears to be much more crystalline. It was found that the average useful lifetimes of the Munich foils were at least ten times longer than arc-deposited foils. Furthermore, they maintained a constant beam output during the time in marked contrast to the arc-deposited foils, for which the output decreased quite rapidly. The longevity, and no less importantly, the constant beam output of the laser-ablated foils have emerged as critical to the continuance of the ERDA program. More significantly though, such qualities have provoked re-examination of likely energies for heavy beams that could be obtained with the Linac booster if foil stripping were used in the 14UD terminal, rather than gas that had previously been considered the only viable option. A program is in progress to explore the means to produce laser-ablated foils, or their equivalent, locally. Extended abstract. 1 ref., 2 figs.

Comparison of carbon stripper foils produced by ARC discharge and laser ablation

International Nuclear Information System (INIS)

Ophel, T.R.; Rhode, A.; Lobanov, N.; Weisser, D.C.; Turkentine, R.; Wolf, B.; Wlliman, R.G.

1998-01-01

The present work describes a series of investigations which compared the arc-deposited foils, prepared at ANU with a batch of foils from Munich, prepared by laser-ablation. The two foil types were bombarded with a beam of 6.8 MeV of 197 Au recording their behaviour and monitoring the total stripped current. Optical and electron spectroscopy was carried out and indicate that the arc-deposited foils were relatively amorphous and smooth, while the laser-ablated foils appears to be much more crystalline. It was found that the average useful lifetimes of the Munich foils were at least ten times longer than arc-deposited foils. Furthermore, they maintained a constant beam output during the time in marked contrast to the arc-deposited foils, for which the output decreased quite rapidly. The longevity, and no less importantly, the constant beam output of the laser-ablated foils have emerged as critical to the continuance of the ERDA program. More significantly though, such qualities have provoked re-examination of likely energies for heavy beams that could be obtained with the Linac booster if foil stripping were used in the 14UD terminal, rather than gas that had previously been considered the only viable option. A program is in progress to explore the means to produce laser-ablated foils, or their equivalent, locally

Influence of pulsed substrate bias on the structure and properties of Ti-Al-N films deposited by cathodic vacuum arc

Energy Technology Data Exchange (ETDEWEB)

Zhang, G.P., E-mail: princeterry@163.com [Institute of Physics, Chinese Academy of Science, Beijing 100080 (China); Gao, G.J. [Changchun University of Science and Technology, College of Science, Changchun 130000 (China); Wang, X.Q.; Lv, G.H.; Zhou, L.; Chen, H.; Pang, H.; Yang, S.Z. [Institute of Physics, Chinese Academy of Science, Beijing 100080 (China)

2012-07-15

Ti-Al-N films were deposited by cathodic vacuum arc (CVA) technique in N{sub 2} atmosphere with different pulsed substrate bias. The influence of pulsed substrate bias (0 to -800 V) on the deposition rate, surface morphology, crystal structure, and mechanical properties of the Ti-Al-N films were systematically investigated. Increasing pulsed bias voltage resulted in the decrease of deposition rate but the increase of surface roughness. It was found that there was a strong correlation between the pulsed bias and film structure. All the films studied in this paper were composed of TiN, AlN, and Ti-Al-N ternary phases. The grains changed from equiaxial to columnar and exhibited preferred orientation when the pulsed bias increased. With the increase of pulsed bias voltage, the atomic ratio of Ti to Al element increased gradually, while the N to (Ti + Al) ratio decreased. The composite films present an enhanced nanohardness compared with binary TiN and ZrN films. The film deposited with pulsed bias of -200 V possessed the maximum scratch critical load and nanohardness. The minimum friction coefficient with pulsed bias of -300 V was obtained.

Welding robot package; Arc yosetsu robot package

Energy Technology Data Exchange (ETDEWEB)

Nishikawa, S. [Yaskawa Electric Corp., Kitakyushu (Japan)

1998-09-01

For the conventional high-speed welding robot, the welding current was controlled mainly for reducing the spatters during short circuits and for stabilizing the beads by the periodic short circuits. However, an increase of deposition amount in response to the speed is required for the high-speed welding. Large-current low-spatter welding current region control was added. Units were integrated into a package by which the arc length is kept in short without dispersion of arc length for welding without defects such as undercut and unequal beads. In automobile industry, use of aluminum parts is extended for the light weight. The welding is very difficult, and automation is not so progressing in spite of the poor environment. Buckling of welding wire is easy to occur, and supply of wire is obstructed by the deposition of chipped powders on the torch cable, which stay within the contact chip resulting in the deposition. Dislocation of locus is easy to occur at the corner of rectangular pipe during the welding. By improving these troubles, an aluminum MIG welding robot package has been developed. 13 figs.

Effect of performance of Zr-Y alloy target on thin film deposition technology

International Nuclear Information System (INIS)

Pan Qianfu; Liu Chaohong; Jiang Mingzhong; Yin Changgeng

2011-01-01

Yttria-stabilized zirconia (YSZ) films are synthesized on corrosion resistant plates by pulsed bias arc ion plating. The arc starting performance and the stability of thin film deposition is explored by improving the uniformity and compactibility of Zr-Y alloy target. The property of Zr-Y alloy target and depositional thin films were measured with the optical microscope, scanning electron microscope, X-ray diffractometer. The result shows that the target with hot rolling and annealing has a good arc starting performance and stability of thin film deposition, and the depositional thin films made of Yttria and amorphous zirconia are homogeneous and compact. (authors)

Weld metal microstructures of hardfacing deposits produced by self-shielded flux-cored arc welding

International Nuclear Information System (INIS)

Dumovic, M.; Monaghan, B.J.; Li, H.; Norrish, J.; Dunne, D.P.

2015-01-01

The molten pool weld produced during self-shielded flux-cored arc welding (SSFCAW) is protected from gas porosity arising from oxygen and nitrogen by reaction ('killing') of these gases by aluminium. However, residual Al can result in mixed micro-structures of δ-ferrite, martensite and bainite in hardfacing weld metals produced by SSFCAW and therefore, microstructural control can be an issue for hardfacing weld repair. The effect of the residual Al content on weld metal micro-structure has been examined using thermodynamic modeling and dilatometric analysis. It is concluded that the typical Al content of about 1 wt% promotes δ-ferrite formation at the expense of austenite and its martensitic/bainitic product phase(s), thereby compromising the wear resistance of the hardfacing deposit. This paper also demonstrates how the development of a Schaeffler-type diagram for predicting the weld metal micro-structure can provide guidance on weld filler metal design to produce the optimum microstructure for industrial hardfacing applications.

Structure of MeCrAlY + AlSi coatings deposited by Arc-PVD method on CMSX4 single crystal alloy

International Nuclear Information System (INIS)

Swadzba, L.; Hetmanczyk, M.; Mendala, B.; Saunders, S.R.J.

2002-01-01

Investigations of depositing high temperature resistant coatings on the Ni base superalloys by Arc-PVD method using exothermic reaction processes between Ni and Al with NiAl intermetallic formation are presented in the article. By the diffusion heating at 1050 o C in vacuum, NiAl diffusion coating containing 21% at. Al and 50 μm thick were obtained. In the next stage coatings with more complex chemical composition - MeCrAlY were formed. The MeCrAlY coatings were made from two targets. Good correlation between the chemical composition of the targets and a uniform distribution of elements in the coatings was shown. Then the surface was also covered with aluminium by the Arc-PVD method . In the vacuum chamber of the equipment a synthesis reaction between NiCoCrAlY and Al with the formation of NiAl intermetallics of high Co, Cr, Y content was initiated. The final heat treatment of coatings was conducted in vacuum at 1323 K. Strong segregation of yttrium into the oxide scale in the specimens heated in the air was shown. It was possible to form NiAl and intermetallics phase coatings modified by Co, Cr and Y by the Arc-PVD method. The coatings were formed on a single crystal CMSX-4. The structure, morphology and phase composition of coatings was carried out. (author)

Effect of Heat Treatment on Microstructure and Mechanical Properties of Inconel 625 Alloy Fabricated by Pulsed Plasma Arc Deposition

Science.gov (United States)

Xu, Fujia; Lv, Yaohui; Liu, Yuxin; Xu, Binshi; He, Peng

Pulsed plasma arc deposition (PPAD) was successfully used to fabricate the Ni-based superalloy Inconel 625 samples. The effects of three heat treatment technologies on microstructure and mechanical properties of the as-deposited material were investigated. It was found that the as-deposited structure exhibited homogenous cellular dendrite structure, which grew epitaxially along the deposition direction. Moreover, some intermetallic phases including Laves phase and MC carbides were precipitated in the interdendritic region as a result of Nb segregation. Compared with the as-deposited microstructure, the direct aged (DA) microstructure changed little except the precipitation of hardening phases γ' and γ" (Ni3Nb), which enhanced the hardness and tensile strength. But the plastic property was inferior due to the existence of brittle Laves phase. After solution and aging heat treatment (STA), a large amount of Laves particles in the interdendritic regions were dissolved, resulting in the reduction of Nb segregation and the precipitation of needle-like δ (Ni3Nb) in the interdendritic regions and grain boundaries. The hardness and tensile strength were improved without sacrificing the ductility. By homogenization and STA heat treatment (HSTA), Laves particles were dissolved into the matrix completely and resulted in recrystallized large grains with bands of annealing twins. The primary MC particles and remaining phase still appeared in the matrix and grain boundaries. Compared with the as-deposited sample, the mechanical properties decreased severely as a result of the grain growth coarsening. The failure modes of all the tensile specimens were analyzed with fractography.

Mathematical Modeling of Metal Active Gas (MAG) Arc Welding

Institute of Scientific and Technical Information of China (English)

无

2001-01-01

In the present paper, a numerical model for MAG (metal active gas) arc welding of thin plate has been developed. In MAG arc welding, the electrode wire is melted and supplied into the molten pool intermittently. Accordingly, it is assumed on the modeling that the thermal energy enters the base-plates through two following mechanisms, i.e., direct heating from arc plasma and “indirect” heating from the deposited metal. In the second part of the paper, MAG arc welding process is numerically analyzed by using the model, and the calculated weld bead dimension and surface profile have been compared with the experimental MAG welds on steel plate. As the result, it is made clear that the model is capable of predicting the bead profile of thin-plate MAG arc welding , including weld bead with undercutting.

Industry-relevant magnetron sputtering and cathodic arc ultra-high vacuum deposition system for in situ x-ray diffraction studies of thin film growth using high energy synchrotron radiation

OpenAIRE

Schroeder, Jeremy; Thomson, W.; Howard, B.; Schell, N.; Näslund, Lars-Åke; Rogström, Lina; Johansson-Jöesaar, Mats P.; Ghafoor, Naureen; Odén, Magnus; Nothnagel, E.; Shepard, A.; Greer, J.; Birch, Jens

2015-01-01

We present an industry-relevant, large-scale, ultra-high vacuum (UHV) magnetron sputtering and cathodic arc deposition system purposefully designed for time-resolved in situ thin film deposition/annealing studies using high-energy (greater than50 keV), high photon flux (greater than10(12) ph/s) synchrotron radiation. The high photon flux, combined with a fast-acquisition-time (less than1 s) two-dimensional (2D) detector, permits time-resolved in situ structural analysis of thin film formation...

Three-dimensional modelling of arc behaviour and gas shield quality in tandem gas-metal arc welding using anti-phase pulse synchronization

International Nuclear Information System (INIS)

Schnick, M; Lohse, M; Fuessel, U; Wilhelm, G; Murphy, A B

2011-01-01

The paper presents a transient three-dimensional model of an anti-phase-synchronized pulsed tandem gas-metal arc welding process, which is used to analyse arc interactions and their influence on the gas shield flow. The shielding gases considered are pure argon and a mixture of argon with 18% CO 2 . Comparison of the temperature fields predicted by the model with high-speed images indicates that the essential features of the interactions between the arcs are captured. The paper demonstrates strong arc deflection and kinking, especially during the low-current phase of the pulse, in agreement with experimental observations. These effects are more distinct for the argon mixture with 18% CO 2 . The second part of the paper demonstrates the effects of arc deflection and instabilities on the shielding gas flow and the occurrence of air contamination in the process region. The results allow an improved understanding of the causes of periodic instabilities and weld seam imperfections such as porosity, spatter, heat-tint oxidation and fume deposits.

Domino Platform: PVD Coaters for Arc Evaporation and High Current Pulsed Magnetron Sputtering

International Nuclear Information System (INIS)

Vetter, J; Müller, J; Erkens, G

2012-01-01

AlTiN and CrN coatings were deposited in hybrid DOMINO platforms by magnetron sputtering (DC-MS, DC-MS+HCP-MS, HCP-MS) and vacuum arc evaporation. The ion cleaning was done by the AEGD process. The coating rates and the energy efficiency of both deposition processes were compared. The roughness effects of the different coating types were discussed. Preliminary results of the change of pulse characteristics during simultaneously running of HCP-MS plus vacuum arc evaporation are shown.

Low-fluorine Stockwork Molybdenite Deposits

Science.gov (United States)

Ludington, Steve; Hammarstrom, Jane; Piatak, Nadine M.

2009-01-01

Low-fluorine stockwork molybdenite deposits are closely related to porphyry copper deposits, being similar in their tectonic setting (continental volcanic arc) and the petrology (calc-alkaline) of associated igneous rock types. They are mainly restricted to the Cordillera of western Canada and the northwest United States, and their distribution elsewhere in the world may be limited. The deposits consist of stockwork bodies of molybdenite-bearing quartz veinlets that are present in and around the upper parts of intermediate to felsic intrusions. The deposits are relatively low grade (0.05 to 0.2 percent Mo), but relatively large, commonly >50 million tons. The source plutons for these deposits range from granodiorite to granite in composition; the deposits primarily form in continental margin subduction-related magmatic arcs, often concurrent with formation of nearby porphyry copper deposits. Oxidation of pyrite in unmined deposits or in tailings and waste rock during weathering can lead to development of acid-rock drainage and limonite-rich gossans. Waters associated with low-fluorine stockwork molybdenite deposits tend to be nearly neutral in pH; variable in concentrations of molybdenum (10,000 ug/L); below regulatory guidelines for copper, iron, lead, zinc, and mercury; and locally may exceed guidelines for arsenic, cadmium, and selenium.

Arc generation from sputtering plasma-dielectric inclusion interactions

International Nuclear Information System (INIS)

Wickersham, C.E. Jr.; Poole, J.E.; Fan, J.S.

2002-01-01

Arcing during sputter deposition and etching is a significant cause of particle defect generation during device fabrication. In this article we report on the effect of aluminum oxide inclusion size, shape, and orientation on the propensity for arcing during sputtering of aluminum targets. The size, shape, and orientation of a dielectric inclusion plays a major role in determining the propensity for arcing and macroparticle emission. In previous studies we found that there is a critical inclusion size required for arcing to occur. In this article we used high-speed videos, electric arc detection, and measurements of particle defect density on wafers to study the effect of Al 2 O 3 inclusion size, shape, and orientation on arc rate, intensity, and silicon wafer particle defect density. We found that the cross-sectional area of the inclusion exposed to the sputtering plasma is the critical parameter that determines the arc rate and rate of macroparticle emission. Analysis of the arc rate, particle defect density, and the intensity of the optical emission from the arcing plasma indicates that the critical aluminum oxide inclusion area for arcing is 0.22±0.1 mm2 when the sputtering plasma sheath dark-space λ d , is 0.51 mm. Inclusions with areas greater than this critical value readily induce arcing and macroparticle ejection during sputtering. Inclusions below this critical size do not cause arcing or macroparticle ejection. When the inclusion major axis is longer than 2λ d and lies perpendicular to the sputter erosion track tangent, the arcing activity increases significantly over the case where the inclusion major axis lies parallel to the erosion track tangent

Laser surface melting of 10 wt% Mo alloyed hardfacing Stellite 12 plasma transferred arc deposits: Structural evolution and high temperature wear performance

Science.gov (United States)

Dilawary, Shaikh Asad Ali; Motallebzadeh, Amir; Afzal, Muhammad; Atar, Erdem; Cimenoglu, Huseyin

2018-05-01

Laser surface melting (LSM) process has been applied on the plasma transferred arc (PTA) deposited Stellite 12 and 10 wt% Mo alloyed Stellite 12 in this study. Following the LSM process, structural and mechanical property comparison of the LSM'ed surfaces has been made. Hardness of the LSM'ed surfaces was measured as 549 HV and 623 HV for the Stellite 12 and Stellite 12 + 10 wt% Mo deposits, respectively. Despite their different hardness and structural features, the LSM'ed surfaces exhibited similar tribological performance at room temperature (RT), where fatigue wear mechanism operates. However, the wear at 500 °C promotes tribo-oxide layer formation whose composition depended on the alloying with Mo. Thus, addition of 10 wt% Mo into Stellite 12 PTA deposit has remarkably enhanced the high temperature wear performance of the LSM'ed surface as a result of participation of complex oxide (CoMoO4) in tribo-oxide layer.

An Alternative Cu-Based Bond Layer for Electric Arc Coating Process

Science.gov (United States)

Fadragas, Carlos R.; Morales, E. V.; Muñoz, J. A.; Bott, I. S.; Lariot Sánchez, C. A.

2011-12-01

A Cu-Al alloy has been used as bond coat between a carbon steel substrate and a final coating deposit obtained by applying the twin wire electric arc spraying coating technique. The presence of a copper-based material in the composite system can change the overall temperature profile during deposition because copper exhibits a thermal conductivity several times higher than that of the normally recommended bond coat materials (such as nickel-aluminum alloys or nickel-chromium alloys). The microstructures of 420 and 304 stainless steels deposited by the electric arc spray process have been investigated, focusing attention on the deposit homogeneity, porosity, lamellar structure, and microhardness. The nature of the local temperature gradient during deposition can strongly influence the formation of the final coating deposit. This study presents a preliminary study, undertaken to investigate the changes in the temperature profile which occur when a Cu-Al alloy is used as bond coat, and the possible consequences of these changes on the microstructure and adhesion of the final coating deposit. The influence of the thickness of the bond layer on the top coating temperature has also been also evaluated.

Development of membrane filters with nanostructured porous layer by coating of metal nanoparticles sintered onto a micro-filter

International Nuclear Information System (INIS)

Park, Seok Joo; Park, Young Ok; Lee, Dong Geun; Ryu, Jeong In

2008-01-01

The membrane filter adhered with nanostructured porous layer was made by heat treatment after deposition of nanoparticle-agglomerates sintered in aerosol phase onto a conventional micron-fibrous metal filter as a substrate filter. The Sintered-Nanoparticle-Agglomerates-coated NanoStructured porous layer Membrane Filter (SNA-NSMF), whose the filtration performance was improved compared with the conventional metal membrane filters, was developed by adhesion of nanoparticle-agglomerates of dendrite structure sintered onto the micron-fibrous metal filter. The size of nanoparticle-agglomerates of dendrite structure decreased with increasing the sintering temperature because nanoparticle-agglomerates shrank. When shrinking nanoparticle-agglomerates were deposited and treated with heat onto the conventional micron-fibrous metal filter, pore size of nanostructured porous layer decreased. Therefore, pressure drops of SNA-NSMFs increased from 0.3 to 0.516 KPa and filtration efficiencies remarkably increased from 95.612 to 99.9993%

Use of pulsed arc welding for butt joint fabrication

International Nuclear Information System (INIS)

Merkulov, B.A.

1977-01-01

A technology of pulsed-arc butt welding with periodic wire feed to the welding zone has been developed. The pulsed arc is suitable both for submerged and gas-shielded weldings. The technology proposed has some advantages over the stationary-arc welding. Control of the amplitude-frequency characteristics of the process enables one to affect melting and crystallization conditions of the welding crater, weld shape, relation between melting and deposited metal section areas, etc., as well as to reduce heat contribution to the base metal. The new process is shown to be applicable in power engineering. Automatic submerged welding conditions are given for low-carbon and pearlitic heat-resistant steels

Sci—Sat AM: Stereo — 08: Stereotactic Ablative Radiotherapy (SABR) for low, intermediate and high risk prostate cancer using Volumetric Modulated Arc Therapy (VMAT) with a 10x Flattening Filter Free (FFF) beam

International Nuclear Information System (INIS)

Mestrovic, A; Fortin, D; Alexander, A

2014-01-01

Purpose: To determine the feasibility of using Volumetric Modulated Arc Therapy (VMAT) with a 10x Flattening Filter Free (FFF) beam for Stereotactic Ablative Radiotherapy (SABR) for low, intermediate and high risk prostate cancer. Methods and Materials: Ten anonymized patient CT data sets were used in this planning study. For each patient CT data set, three sets of contours were generated: 1) low risk, 2) intermediate risk, and 3) high risk scenarios. For each scenario, a single-arc and a double-arc VMAT treatment plans were created. Plans were generated with the Varian Eclipse™ treatment planning system for a Varian TrueBeam™ linac equipped with Millenium 120 MLC. Plans were created using a 10x-FFF beam with a maximum dose rate of 2400 MU/min. Dose prescription was 36.25Gy/5 fractions with the planning objective of covering 99% of the Planning Target Volume with the 95% of the prescription dose. Normal tissue constraints were based on provincial prostate SABR planning guidelines, derived from national and international prostate SABR protocols. Plans were evaluated and compared in terms of: 1) dosimetric plan quality, and 2) treatment delivery efficiency. Results: Both single-arc and double-arc VMAT plans were able to meet the planning goals for low, intermediate and high risk scenarios. No significant dosimetric differences were observed between the plans. However, the treatment time was significantly lower for a single-arc VMAT plans. Conclusions: Prostate SABR treatments are feasible with 10x-FFF VMAT technique. A single-arc VMAT offers equivalent dosimetric plan quality and a superior treatment delivery efficiency, compared to a double-arc VMAT

Use of an arc plasma rotating in a magnetic field for metal coating glass substrates

International Nuclear Information System (INIS)

Vukanovic, V.; Butler, S.; Kapur, S.; Krakower, E.; Allston, T.; Belfield, K.; Gibson, G.

1983-01-01

First results are reported about deposition of metals on glass substrate using a low current arc plasma source at atmospheric pressure. The arc source consists of a graphite cathode rod placed on the axis of a graphite anode cylinder aligned in a magnetic field. The carrier gas is argon. The deposition material, zinc or gold, is evaporated from a reservoir in the cathode. Depositions on flat substrates positioned on the periphery of the rotating plasma within the anode tube and in a jet outside the anode have been investigated. The investigations are planned to lead towards laser fusion target pusher layer fabrication. This fabrication would be facilitated by a high pressure deposition process where target levitation is readily performed

High-Temperature Oxidation and Smelt Deposit Corrosion of Ni-Cr-Ti Arc-Sprayed Coatings

Science.gov (United States)

Matthews, S.; Schweizer, M.

2013-08-01

High Cr content Ni-Cr-Ti arc-sprayed coatings have been extensively applied to mitigate corrosion in black liquor recovery boilers in the pulp and paper industry. In a previous article, the effects of key spray parameters on the coating's microstructure and its composition were investigated. Three coating microstructures were selected from that previous study to produce a dense, oxidized coating (coating A), a porous, low oxide content coating (coating B), and an optimized coating (coating C) for corrosion testing. Isothermal oxidation trials were performed in air at 550 and 900 °C for 30 days. Additional trials were performed under industrial smelt deposits at 400 and 800 °C for 30 days. The effect of the variation in coating microstructure on the oxidation and smelt's corrosion response was investigated through the characterization of the surface corrosion products, and the internal coating microstructural developments with time at high temperature. The effect of long-term, high-temperature exposure on the interaction between the coating and substrate was characterized, and the mechanism of interdiffusion was discussed.

Modified IRC bench-scale arc melter for waste processing

International Nuclear Information System (INIS)

Eddy, T.L.; Sears, J.W.; Grandy, J.D.; Kong, P.C.; Watkins, A.D.

1994-03-01

This report describes the INEL Research Center (IRC) arc melter facility and its recent modifications. The arc melter can now be used to study volatilization of toxic and high vapor pressure metals and the effects of reducing and oxidizing (redox) states in the melt. The modifications include adding an auger feeder, a gas flow control and monitoring system, an offgas sampling and exhaust system, and a baghouse filter system, as well as improving the electrode drive, slag sampling system, temperature measurement and video monitoring and recording methods, and oxidation lance. In addition to the volatilization and redox studies, the arc melter facility has been used to produce a variety of glass/ceramic waste forms for property evaluation. Waste forms can be produced on a daily basis. Some of the melts performed are described to illustrate the melter's operating characteristics

Deposition and characterization of titania-silica optical multilayers by asymmetric bipolar pulsed dc sputtering of oxide targets

Energy Technology Data Exchange (ETDEWEB)

Sagdeo, P R; Shinde, D D; Misal, J S [Optics and Thin Film Laboratory, Autonagar, BARC-Vizag, Visakhapatnam -530012 (India); Kamble, N M; Tokas, R B; Biswas, A; Poswal, A K; Thakur, S; Bhattacharyya, D; Sahoo, N K; Sabharwal, S C, E-mail: nksahoo@barc.gov.i, E-mail: sahoonk@gmail.co [Spectroscopy Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

2010-02-03

Titania-silica (TiO{sub 2}/SiO{sub 2}) optical multilayer structures have been conventionally deposited by reactive sputtering of metallic targets. In order to overcome the problems of arcing, target poisoning and low deposition rates encountered there, the application of oxide targets was investigated in this work with asymmetric bipolar pulsed dc magnetron sputtering. In order to evaluate the usefulness of this deposition methodology, an electric field optimized Fabry Perot mirror for He-Cd laser ({lambda} = 441.6 nm) spectroscopy was deposited and characterized. For comparison, this mirror was also deposited by the reactive electron beam (EB) evaporation technique. The mirrors developed by the two complementary techniques were investigated for their microstructural and optical reflection properties invoking atomic force microscopy, ellipsometry, grazing incidence reflectometry and spectrophotometry. From these measurements the layer geometry, optical constants, mass density, topography, surface and interface roughness and disorder parameters were evaluated. The microstructural properties and spectral functional characteristics of the pulsed dc sputtered multilayer mirror were found to be distinctively superior to the EB deposited mirror. The knowledge gathered during this study has been utilized to develop a 21-layer high-pass edge filter for radio photoluminescence dosimetry.

Deposition and characterization of titania-silica optical multilayers by asymmetric bipolar pulsed dc sputtering of oxide targets

International Nuclear Information System (INIS)

Sagdeo, P R; Shinde, D D; Misal, J S; Kamble, N M; Tokas, R B; Biswas, A; Poswal, A K; Thakur, S; Bhattacharyya, D; Sahoo, N K; Sabharwal, S C

2010-01-01

Titania-silica (TiO 2 /SiO 2 ) optical multilayer structures have been conventionally deposited by reactive sputtering of metallic targets. In order to overcome the problems of arcing, target poisoning and low deposition rates encountered there, the application of oxide targets was investigated in this work with asymmetric bipolar pulsed dc magnetron sputtering. In order to evaluate the usefulness of this deposition methodology, an electric field optimized Fabry Perot mirror for He-Cd laser (λ = 441.6 nm) spectroscopy was deposited and characterized. For comparison, this mirror was also deposited by the reactive electron beam (EB) evaporation technique. The mirrors developed by the two complementary techniques were investigated for their microstructural and optical reflection properties invoking atomic force microscopy, ellipsometry, grazing incidence reflectometry and spectrophotometry. From these measurements the layer geometry, optical constants, mass density, topography, surface and interface roughness and disorder parameters were evaluated. The microstructural properties and spectral functional characteristics of the pulsed dc sputtered multilayer mirror were found to be distinctively superior to the EB deposited mirror. The knowledge gathered during this study has been utilized to develop a 21-layer high-pass edge filter for radio photoluminescence dosimetry.

Geometrical and electromagnetic effects on arc propagation in a railplug ignitor

Energy Technology Data Exchange (ETDEWEB)

Ekici, O; Matthews, R D; Ezekoye, O A [Department of Mechanical Engineering, University of Texas at Austin, Austin, TX 78712-106 (United States)

2007-12-21

Three-dimensional simulation of arc motion is presented for conditions representative of those for a railplug ignitor. A railplug ignitor is a miniature rail-gun used to deliver an arc ignition source for internal combustion engine applications. Computations explored the influence of the railplug geometry, effects of an external magnetic field, and impact of the circuit current on arc velocity. One underlying question about arc motion in railplug systems has been the influence of the expansion velocity associated with energy deposition on arc motion. A single open end muzzle would result in higher velocities if the expansion effects are dominant. This was tested by simulating two types of geometries, single open end and double open end muzzles. The double open end configuration was shown to have faster arc propagation velocities. A discussion of the mechanisms is presented. A simple scaling analysis was found to explain the increased arc propagation velocity associated with application of an external magnetic field. Increasing the circuit current was found to increase the final arc propagation velocity, although the early time velocities were slower for larger currents.

Geometrical and electromagnetic effects on arc propagation in a railplug ignitor

International Nuclear Information System (INIS)

Ekici, O; Matthews, R D; Ezekoye, O A

2007-01-01

Three-dimensional simulation of arc motion is presented for conditions representative of those for a railplug ignitor. A railplug ignitor is a miniature rail-gun used to deliver an arc ignition source for internal combustion engine applications. Computations explored the influence of the railplug geometry, effects of an external magnetic field, and impact of the circuit current on arc velocity. One underlying question about arc motion in railplug systems has been the influence of the expansion velocity associated with energy deposition on arc motion. A single open end muzzle would result in higher velocities if the expansion effects are dominant. This was tested by simulating two types of geometries, single open end and double open end muzzles. The double open end configuration was shown to have faster arc propagation velocities. A discussion of the mechanisms is presented. A simple scaling analysis was found to explain the increased arc propagation velocity associated with application of an external magnetic field. Increasing the circuit current was found to increase the final arc propagation velocity, although the early time velocities were slower for larger currents

Dissolution behaviour of 238U, 234U and 230Th deposited on filters from personal dosemeters

International Nuclear Information System (INIS)

Beckova, V.; Malatova, I.

2008-01-01

Kinetics of dissolution of 238 U, 234 U and 230 Th dust deposited on filters from personal alpha dosemeters was studied by means of a 26-d in vitro dissolution test with a serum ultra-filtrate simulant. Dosemeters had been used by miners at the uranium mine 'Dolni Rozinka' at Rozna, Czech Republic. The sampling flow-rate as declared by the producer is 4 l h -1 and the sampling period is typically 1 month. Studied filters contained 125 ± 6 mBq 238 U in equilibrium with 234 U and 230 Th; no 232 Th series nuclides were found. Half-time of rapid dissolution of 1.4 d for 238 U and 234 U and slow dissolution half-times of 173 and 116 d were found for 238 U and 234 U, respectively. No detectable dissolution of 230 Th was found. (authors)

Industry-relevant magnetron sputtering and cathodic arc ultra-high vacuum deposition system for in situ x-ray diffraction studies of thin film growth using high energy synchrotron radiation.

Science.gov (United States)

Schroeder, J L; Thomson, W; Howard, B; Schell, N; Näslund, L-Å; Rogström, L; Johansson-Jõesaar, M P; Ghafoor, N; Odén, M; Nothnagel, E; Shepard, A; Greer, J; Birch, J

2015-09-01

We present an industry-relevant, large-scale, ultra-high vacuum (UHV) magnetron sputtering and cathodic arc deposition system purposefully designed for time-resolved in situ thin film deposition/annealing studies using high-energy (>50 keV), high photon flux (>10(12) ph/s) synchrotron radiation. The high photon flux, combined with a fast-acquisition-time (film formation processes. The high-energy synchrotron-radiation based x-rays result in small scattering angles (industry-relevant processes. We openly encourage the materials research community to contact us for collaborative opportunities using this unique and versatile scientific instrument.

Simulation of Rn-222 decay products concentration deposited on a filter. Description of radon1.pas computer program

International Nuclear Information System (INIS)

Machaj, B.

1996-01-01

A computer program allowing simulation of activity distribution of 222 Rn short lived decay products deposited on a filter against time is presented, for any radiation equilibrium degree of the decay products. Deposition of the decay products is simulated by summing discrete samples every 1/10 min in the sampling time from 1 to 10 min. The concentration (activity) of the decay products is computed in one minute intervals in the range 1 - 100 min. The alpha concentration and the total activity of 218 Po + 214 Po produced are computed in the range 1 to 100 min as well. (author). 10 refs, 4 figs

The emotional arcs of stories are dominated by six basic shapes

Directory of Open Access Journals (Sweden)

Andrew J Reagan

2016-11-01

Full Text Available Abstract Advances in computing power, natural language processing, and digitization of text now make it possible to study a culture’s evolution through its texts using a ‘big data’ lens. Our ability to communicate relies in part upon a shared emotional experience, with stories often following distinct emotional trajectories and forming patterns that are meaningful to us. Here, by classifying the emotional arcs for a filtered subset of 1,327 stories from Project Gutenberg’s fiction collection, we find a set of six core emotional arcs which form the essential building blocks of complex emotional trajectories. We strengthen our findings by separately applying matrix decomposition, supervised learning, and unsupervised learning. For each of these six core emotional arcs, we examine the closest characteristic stories in publication today and find that particular emotional arcs enjoy greater success, as measured by downloads.

Development of data processing system for regional geophysical and geochemical exploration of sandstone-hosted uranium deposits based on ArcGIS Engine

International Nuclear Information System (INIS)

Han Shaoyang; Ke Dan; Hou Huiqun; Hu Shuiqing

2010-01-01

According to the data processing need of geophysical and geochemical exploration of sandstone-hosted uranium deposits, the function design of the regional geophysical and geochemical data processing system is completed in the paper. The geophysical and geochemical data processing software with powerful functions is also developed based on ArcGIS Engine which remedies the shortage of GIS software for performing the geophysical and geochemical data processing. The development technique route of system software and key techniques are introduced, and the development processes of system software are showed through some development examples. Application practices indicate that the interface of developed system software with friendly interface and utility functions, may quickly perform the data processing of regional geophysical and geochemical exploration and provide the helpful deep information for predicting metallogenic prospective areas of sandstone-hosted uranium deposits. The system software is of a great application foreground. (authors)

Lithospheric Contributions to Arc Magmatism: Isotope Variations Along Strike in Volcanoes of Honshu, Japan

Science.gov (United States)

Kersting; Arculus; Gust

1996-06-07

Major chemical exchange between the crust and mantle occurs in subduction zone environments, profoundly affecting the chemical evolution of Earth. The relative contributions of the subducting slab, mantle wedge, and arc lithosphere to the generation of island arc magmas, and ultimately new continental crust, are controversial. Isotopic data for lavas from a transect of volcanoes in a single arc segment of northern Honshu, Japan, have distinct variations coincident with changes in crustal lithology. These data imply that the relatively thin crustal lithosphere is an active geochemical filter for all traversing magmas and is responsible for significant modification of primary mantle melts.

SU-E-T-311: Dosimetric Comparison of Volumetric Modulated Arc Therapy Plans for Preoperative Radiotherapy Rectal Cancer Using Flattening Filter-Free and Flattening Filter Modes

Energy Technology Data Exchange (ETDEWEB)

Zhang, W; Zhang, J; Lu, J; Chen, C [Cancer Hospital of Shantou University Medical College, Shantou, Guangdong (China)

2015-06-15

Purpose: To compare the dosimetric difference of volumetric modulated arc therapy(VMAT) for preoperative radiotherapy rectal cancer using 6MV X-ray flattening filter free(FFF) and flattening filter(FF) modes. Methods: FF-VMAT and FFF-VMAT plans were designed to 15 rectal cancer patients with preoperative radiotherapy by planning treatment system(Eclipse 10.0),respectively. Dose prescription was 50 Gy in 25 fractions. All plans were normalized to 50 Gy to 95% of PTV. The Dose Volume Histogram (DVH), target and risk organ doses, conformity indexes (CI), homogeneity indexes (HI), low dose volume of normal tissue(BP), monitor units(MU) and treatment time (TT) were compared between the two kinds of plans. Results: FF-VMAT provided the lower Dmean, V105, HI, and higher CI as compared with FFF-VMAT. The small intestine of D5, Bladder of D5, Dmean, V40, V50, L-femoral head of V40, R-femoral head of Dmean were lower in FF-VMAT than in FFF-VMAT. FF-VMAT had higher BP of V5, but no significantly different of V10, V15, V20, V30 as compared with FFF-VMAT. FF-VMAT reduceed the monitor units(MU) by 21%(P<0.05), as well as the treatment time(TT) was no significantly different(P>0.05), as compared with FFF-VMAT. Conclusion: The plan qualities of FF and FFF VMAT plans were comparable and both clinically acceptable. FF-VMAT as compared with FFF-VMAT, showing better target coverage, some of OARs sparing, the MUs of FFF-VMAT were higher than FF-VMAT, yet were delivered within the same time. This work was supported by the Medical Scientific Research Foundation of Guangdong Procvince (A2014455 to Changchun Ma)

Arc tracking energy balance for copper and aluminum aeronautic cables

International Nuclear Information System (INIS)

André, T; Valensi, F; Teulet, P; Cressault, Y; Zink, T; Caussé, R

2017-01-01

Arc tracking tests have been carried out between two voluntarily damaged aeronautic cables. Copper or aluminum conductors have been exposed to short circuits under alternating current. Various data have been recorded (arc voltage and current, radiated power and ablated mass), enabling to determine a power balance, in which every contribution is estimated. The total power is mainly transferred to the cables (between 50 and 65%, depending on the current and the cable type), and causes the melting and partial vaporization of the metallic core and insulating material, or is conducted or radiated. The other part is deposited into the arc column, being either radiated, convected or conducted. (paper)

Architecture and mineral deposit settings of the Altaid orogenic collage: a revised model

Science.gov (United States)

Yakubchuk, Alexander

2004-09-01

The Altaids are an orogenic collage of Neoproterozoic-Paleozoic rocks located in the center of Eurasia. This collage consists of only three oroclinally bent Neoproterozoic-Early Paleozoic magmatic arcs (Kipchak, Tuva-Mongol, and Mugodzhar-Rudny Altai), separated by sutures of their former backarc basins, which were stitched by new generations of overlapping magmatic arcs. In addition, the Altaids host accreted fragments of the Neoproterozoic to Early Paleozoic oceanic island chains and Neoproterozoic to Cenozoic plume-related magmatic rocks superimposed on the accreted fragments. All these assemblages host important, many world-class, Late Proterozoic to Early Mesozoic gold, copper-molybdenum, lead-zinc, nickel and other deposits of various types. In the Late Proterozoic, during breakup of the supercontinent Rodinia, the Kipchak and Tuva-Mongol magmatic arcs were rifted off Eastern Europe-Siberia and Laurentia to produce oceanic backarc basins. In the Late Ordovician, the Siberian craton began its clockwise rotation with respect to Eastern Europe and this coincides with the beginning of formation of the Mugodzhar-Rudny Altai arc behind the Kipchak arc. These earlier arcs produced mostly Cu-Pb-Zn VMS deposits, although some important intrusion-related orogenic Au deposits formed during arc-arc collision events in the Middle Cambrian and Late Ordovician. The clockwise rotation of Siberia continued through the Paleozoic until the Early Permian producing several episodes of oroclinal bending, strike-slip duplication and reorganization of the magmatic arcs to produce the overlapping Kazakh-Mongol and Zharma-Saur-Valerianov-Beltau-Kurama arcs that welded the extinct Kipchak and Tuva-Mongol arcs. This resulted in amalgamation of the western portion of the Altaid orogenic collage in the Late Paleozoic. Its eastern portion amalgamated only in the early Mesozoic and was overlapped by the Transbaikal magmatic arc, which developed in response to subduction of the oceanic crust

Microstructure and mechanical performance of depositing CuSi3 Cu alloy onto 30CrMnSi steel plate by the novel consumable and non-consumable electrodes indirect arc welding

International Nuclear Information System (INIS)

Wang, Jun; Cao, Jian; Feng, Jicai

2010-01-01

A novel consumable and non-consumable electrodes indirect arc welding (CNC-IAW) with low heat input was successfully applied in depositing CuSi 3 Cu alloy onto 30CrMnSi steel plate. The indirect arc was generated between the consumable and non-consumable welding torch. The microstructure of the deposited weld was analyzed by means of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and optical microscopy (OM). The results showed that the dilution ratio of the bead-on-plate weld was controlled no higher than 5% and the deleterious iron picking up was effectively restrained. The deposited metal mainly consisted of ε-Cu solid solution and a small amount of Fe 2 Si phase. In the interfacial zone between the deposited metal and base metal, the thickness of the zone changed from thick to thin and the microstructure changed from complex to simple from the middle to both sides. In the middle of the interfacial zone, the microstructure presented three sub-layers consisting of Fe 3 Si (L)/Fe 3 Si (S) + ε-Cu/α-Fe. In the both sides of the interfacial zone, the microstructure presented single α-Fe layer. The formation mechanism of the interfacial zone could be successfully explained by the formation of the Fe liquid-solid phase zone adjacent to the Fe base metal and the interfusion between Fe and Si. The average compressive shear strength reached 321 MPa and its fracture morphology mainly belonged to ductile fracture.

Feasibility of arc-discharge and plasma-sputtering methods in cleaning plasma-facing and diagnostics components of fusion reactors

Energy Technology Data Exchange (ETDEWEB)

Hakola, Antti, E-mail: antti.hakola@vtt.fi [VTT Technical Research Centre of Finland, VTT (Finland); Likonen, Jari [VTT Technical Research Centre of Finland, VTT (Finland); Karhunen, Juuso; Korhonen, Juuso T. [Department of Applied Physics, Aalto University (Finland); Aints, Märt; Laan, Matti; Paris, Peeter [Department of Physics, University of Tartu (Estonia); Kolehmainen, Jukka; Koskinen, Mika; Tervakangas, Sanna [DIARC-Technology Oy, Espoo (Finland)

2015-10-15

Highlights: • Feasibility of the arc-discharge and plasma-sputtering techniques in removing deposited layers from ITER-relevant samples demonstrated. • Samples with the size of an A4 paper can be cleaned from 1-μm thick deposited layers in 10–20 minutes by the arc-discharge method. • The plasma-sputtering method is 5–10 times slower but the resulting surfaces are very smooth. • Arc-discharge method could be used for rapid cleaning of plasma-facing components during maintenance shutdowns of ITER, plasma sputtering is preferred for diagnostics mirrors. - Abstract: We have studied the feasibility of arc-discharge and plasma-sputtering methods in removing deposited layers from ITER-relevant test samples. Prototype devices have been designed and constructed for the experiments and the cleaning process is monitored by a spectral detection system. The present version of the arc-discharge device is capable of removing 1-μm thick layers from 350-mm{sup 2} areas in 4–8 s, but due to the increased roughness of the cleaned surfaces and signs of local melting, mirror-like surfaces cannot be treated by this technique. The plasma-sputtering approach, for its part, is some 5–10 times slower in removing the deposited layers but no changes in surface roughness or morphology of the samples could be observed after the cleaning phase. The arc-discharge technique could therefore be used for rapid cleaning of plasma-facing components during maintenance shutdowns of ITER while in the case of diagnostics mirrors plasma sputtering is preferred.

Selective formation of diamond-like carbon coating by surface catalyst patterning

DEFF Research Database (Denmark)

Palnichenko, A.V.; Mátéfi-Tempfli, M.; Mátéfi-Tempfli, Stefan

2004-01-01

The selective formation of diamond-like carbon coating by surface catalyst patterning was studied. DLC films was deposited using plasma enhanced chemical vapor deposition, filtered vacuum arc deposition, laser ablation, magnetron sputtering and ion-beam lithography methods. The DLC coatings were...

Preparation and characterization of micro-arc-induced Pd/TM(TM = Ni, Co and Ti) catalysts and comparison of their electrocatalytic activities toward ethanol oxidation

International Nuclear Information System (INIS)

Wang, Xiaoguang; Ma, Guanshui; Zhu, Fuchun; Lin, Naiming; Tang, Bin; Zhang, Zhonghua

2013-01-01

Using the electro-spark deposition technique, a novel kind of Pd/TM (TM = Ni, Co and Ti) electrode was successfully prepared by arc-depositing Pd on the transition metal substrates. The structure, morphology and chemical composition of the arc-deposited films were investigated using thin-film X-ray diffraction (TF-XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The results show that, a coarsening topographical morphology can be obtained, being composed of numerous craters/spots with sizes ranging from nano-scales to several microns. The electrochemical measurements indicate that the arc-deposited Pd/TM electrodes exhibit distinct electrochemical behaviors and the catalytic activity toward ethanol electro-oxidation reaction (EOR) is highly dependent upon the nature of substrate. Among the Pd/TM electrodes investigated, the arc-deposited Pd/Co reveals the best activity and superior poisoning tolerance towards ethanol oxidation and will find promising applications as a candidate for the anode catalyst of direct ethanol fuel cells (DEFCs)

Atmospheric pressure arc discharge with ablating graphite anode

International Nuclear Information System (INIS)

Nemchinsky, V A; Raitses, Y

2015-01-01

The anodic carbon arc discharge is used to produce carbon nanoparticles. Recent experiments with the carbon arc at atmospheric pressure helium demonstrated the enhanced ablation rate for narrow graphite anodes resulting in high deposition rates of carbonaceous products on the copper cathode (Fetterman et al 2008 Carbon 46 1322–6). The proposed model explains these results with interconnected steady-state models of the cathode and the anode processes. When considering cathode functioning, the model predicts circulation of the particles in the near-cathode region: evaporation of the cathode material, ionization of evaporated atoms and molecules in the near-cathode plasma, return of the resulting ions to the cathode, surface recombination of ions and electrons followed again by cathode evaporation etc. In the case of the low anode ablation rate, the ion acceleration in the cathode sheath provides the major cathode heating mechanism. In the case of an intensive anode ablation, an additional cathode heating is due to latent fusion heat of the atomic species evaporated from the anode and depositing at the cathode. Using the experimental arc voltage as the only input discharge parameter, the model allows us to calculate the anode ablation rate. A comparison of the results of calculations with the available experimental data shows reasonable agreement. (paper)

Atmospheric pressure arc discharge with ablating graphite anode

Science.gov (United States)

Nemchinsky, V. A.; Raitses, Y.

2015-06-01

The anodic carbon arc discharge is used to produce carbon nanoparticles. Recent experiments with the carbon arc at atmospheric pressure helium demonstrated the enhanced ablation rate for narrow graphite anodes resulting in high deposition rates of carbonaceous products on the copper cathode (Fetterman et al 2008 Carbon 46 1322-6). The proposed model explains these results with interconnected steady-state models of the cathode and the anode processes. When considering cathode functioning, the model predicts circulation of the particles in the near-cathode region: evaporation of the cathode material, ionization of evaporated atoms and molecules in the near-cathode plasma, return of the resulting ions to the cathode, surface recombination of ions and electrons followed again by cathode evaporation etc. In the case of the low anode ablation rate, the ion acceleration in the cathode sheath provides the major cathode heating mechanism. In the case of an intensive anode ablation, an additional cathode heating is due to latent fusion heat of the atomic species evaporated from the anode and depositing at the cathode. Using the experimental arc voltage as the only input discharge parameter, the model allows us to calculate the anode ablation rate. A comparison of the results of calculations with the available experimental data shows reasonable agreement.

Dissolution behaviour of 238U, 234U and 230Th deposited on filters from personal dosemeters.

Science.gov (United States)

Becková, Vera; Malátová, Irena

2008-01-01

Kinetics of dissolution of (238)U, (234)U and (230)Th dust deposited on filters from personal alpha dosemeters was studied by means of a 26-d in vitro dissolution test with a serum ultrafiltrate simulant. Dosemeters had been used by miners at the uranium mine 'Dolní Rozínka' at Rozná, Czech Republic. The sampling flow-rate as declared by the producer is 4 l h(-1) and the sampling period is typically 1 month. Studied filters contained 125 +/- 6 mBq (238)U in equilibrium with (234)U and (230)Th; no (232)Th series nuclides were found. Half-time of rapid dissolution of 1.4 d for (238)U and (234)U and slow dissolution half-times of 173 and 116 d were found for (238)U and (234)U, respectively. No detectable dissolution of (230)Th was found.

Structural evolution of Ti destroyable interlayer in large-size diamond film deposition by DC arc plasma jet

Science.gov (United States)

Guo, Jianchao; Li, Chengming; Liu, Jinlong; Wei, Junjun; Chen, Liangxian; Hua, Chenyi; Yan, Xiongbo

2016-05-01

The addition of titanium (Ti) interlayer was verified to reduce the residual stress of diamond films by self-fracturing and facilitate the harvest of a crack-free free-standing diamond film prepared by direct current (DC) arc plasma jet. In this study, the evolution of the Ti interlayer between large-area diamond film and substrate was studied and modeled in detail. The evolution of the interlayer was found to be relevant to the distribution of the DC arc plasma, which can be divided into three areas (arc center, arc main, and arc edge). The formation rate of titanium carbide (TiC) in the arc main was faster than in the other two areas and resulted in the preferred generation of crack in the diamond film in the arc main during cooling. Sandwich structures were formed along with the growth of TiC until the complete transformation of the Ti interlayer. The interlayer released stress via self-fracture. Avoiding uneven fragile regions that formed locally in the interlayer and achieving cooperatively released stress are crucial for the preparation of large crack-free diamond films.

Sedimentary Record of the Back-Arc Basins of South-Central Mexico: an Evolution from Extensional Basin to Carbonate Platform.

Science.gov (United States)

Sierra-Rojas, M. I.; Molina-Garza, R. S.; Lawton, T. F.

2015-12-01

The Lower Cretaceous depositional systems of southwestern Oaxaquia, in south-central Mexico, were controlled by tectonic processes related to the instauration of a continental arc and the accretion of the Guerrero arc to mainland Mexico. The Atzompa Formation refers to a succession of conglomerate, sandstone, siltstone, and limestone that crop out in southwestern Mexico with Early Cretaceous fauna and detrital zircon maximum depositional ages. The sedimentary record shows a transition from early fluvial/alluvial to shallow marine depositional environments. The first stage corresponds to juvenile fluvial/alluvial setting followed by a deep lacustrine depositional environment, suggesting the early stages of an extensional basin. The second stage is characterized by anabranched deposits of axial fluvial systems flowing to the NE-SE, showing deposition during a period of rapid subsidence. The third and final stage is made of tidal deposits followed, in turn, by abrupt marine flooding of the basin and development of a Barremian-Aptian carbonate ramp. We interpret the Tentzo basin as a response to crustal extension in a back-arc setting, with high rates of sedimentation in the early stages of the basin (3-4 mm/m.y), slower rates during the development of starved fluvial to tidal systems and carbonate ramps, and at the top of the Atzompa Formation an abrupt deepening of the basin due to flexural subsidence related to terrane docking and attendant thrusting to the west. These events were recorded in the back-arc region of a continental convergent margin (Zicapa arc) where syn-sedimentary magmatism is indicated by Early Cretaceous detrital and volcanic clasts from alluvial fan facies west of the basin. Finally, and as a response to the accretion of the Guerrero superterrane to Oaxaquia during the Aptian, a carbonate platform facing toward the Gulf of Mexico was established in central to eastern Oaxaquia.

Modernization of serial facility 'BULAT-6' for synthesis of vacuum-arc coatings by the method of plasma-based ion implantation and deposition as well as ion hydrogen-free nitriding

International Nuclear Information System (INIS)

Shulaev, V.M.; Andreev, A.A.; Rudenko, V.P.

2008-01-01

The model of laboratory vacuum-arc facility for realization of the method of plasma-based ion implantation and deposition is worked out by means modernization of serial industrial facility 'BULAT-6'. The facility is suitable for surface modification of instrumental steel items, including the low-alloyed steels with low temperatures of tempering. The low-temperature deposition of coatings on the preliminary nitrided surface of instrument permits obtaining dense coating with minimum maintenance of macroparticles, as well as with coatings superhigh adhesion to the substrate and with superhardness. The coatings possess high property stableness in time.

Effects of hydrogenation on thermal conductivity of ultrananocrystalline diamond/amorphous carbon composite films prepared via coaxial arc plasma deposition

Science.gov (United States)

Takeichi, Satoshi; Nishiyama, Takashi; Tabara, Mitsuru; Kawawaki, Shuichi; Kohno, Masamichi; Takahashi, Koji; Yoshitake, Tsuyoshi

2018-06-01

Ultrananocrystalline diamond (UNCD)/hydrogenated amorphous carbon (a-C:H) composite (UNCD/a-C:H) and UNCD/non-hydrogenated amorphous carbon (a-C) composite (UNCD/a-C) films were prepared via coaxial arc plasma deposition, and their thermal conductivity and interfacial conductance in grain boundaries were measured using a time-domain thermoreflectance method. The interfacial conductance was estimated to be 1,010 and 4,892 MW/(m2·K) for UNCD/a-C:H and UNCD/a-C films, respectively. The reasons for the hydrogenated film having lower interfacial conductance than the non-hydrogenated film are 1) the reduced number of carriers that contribute to heat transport and 2) the hydrogen atoms, which are preferentially located at the grain boundaries and enhance phonon scattering.

Characterization of duplex stainless steel weld metals obtained by hybrid plasma-gas metal arc welding

OpenAIRE

Yurtisik,Koray; Tirkes,Suha; Dykhno,Igor; Gur,C. Hakan; Gurbuz,Riza

2013-01-01

Despite its high efficiency, autogenous keyhole welding is not well-accepted for duplex stainless steels because it causes excessive ferrite in as-welded duplex microstructure, which leads to a degradation in toughness and corrosion properties of the material. Combining the deep penetration characteristics of plasma arc welding in keyhole mode and metal deposition capability of gas metal arc welding, hybrid plasma - gas metal arc welding process has considered for providing a proper duplex mi...

Deposition of Coating to Protect Waste Water Reservoir in Acidic Solution by Arc Thermal Spray Process

Directory of Open Access Journals (Sweden)

Han-Seung Lee

2018-01-01

Full Text Available The corrosion characteristics of 304 stainless steel (SS and titanium (Ti coatings deposited by the arc thermal spray process in pH 4 solution were assessed. The Ti-sprayed coating exhibits uniform, less porous, and adherent coating morphology compared to the SS-sprayed coating. The electrochemical study, that is, electrochemical impedance spectroscopy (EIS, revealed that as exposure periods to solution were increased, the polarization resistance (Rp decreased and the charge transfer resistance (Rct increased owing to corrosion of the metallic surface and simultaneously at the same time the deposition of oxide films/corrosion on the SS-sprayed surface, while Ti coating transformed unstable oxides into the stable phase. Potentiodynamic studies confirmed that both sprayed coatings exhibited passive tendency attributed due to the deposition of corrosion products on SS samples, whereas the Ti-sprayed sample formed passive oxide films. The Ti coating reduced the corrosion rate by more than six times compared to the SS coating after 312 h of exposure to sulfuric acid- (H2SO4- contaminated water solution, that is, pH 4. Scanning electron microscope (SEM results confirmed the uniform and globular morphology of the passive film on the Ti coating resulting in reduced corrosion. On the other hand, the corrosion products formed on SS-sprayed coating exhibit micropores with a net-like microstructure. X-ray diffraction (XRD revealed the presence of the composite oxide film on Ti-sprayed samples and lepidocrocite (γ-FeOOH on the SS-coated surface. The transformation of TiO and Ti3O into TiO2 (rutile and anatase and Ti3O5 after 312 h of exposure to H2SO4 acid reveals the improved corrosion resistance properties of Ti-sprayed coating.

MO-H-19A-02: Investigation of Modulated Electron Arc (MeArc) Therapy for the Treatment of Scalp Tumors

Energy Technology Data Exchange (ETDEWEB)

Eldib, A [Fox Chase Cancer Center, Philadelphia, PA (United States); Al-Azhar University, Cairo (Egypt); Jin, L; Martin, J; Li, J; Chibani, O; Galloway, T; Ma, C [Fox Chase Cancer Center, Philadelphia, PA (United States)

2014-06-15

Purpose: Electron arc therapy has long been proposed as the most suitable technique for the treatment of superficial tumors that follow circularly curved surfaces. However it was challenged by unsuitability of the conventional applicators and the lack of adequate 3-D dose calculation tools for arc electron beams in the treatment planning systems (TPS). Now with the availability of an electron specific multi-leaf collimator (eMLC) and an in-house Monte Carlo (MC) based TPS, we were motivated to investigate more advanced modulated electron arc (MeARC) therapy and its beneficial outcome. Methods: We initiated the study by a film measurement conducted in a head and neck phantom, where we delivered electron arcs in a step and shoot manner using the light field as a guide to avoid fields abutments. This step was done to insure enough clearance for the arcs with eMLC. MCBEAM and MCPLAN MC codes were used for the treatment head simulation and phantom dose calculation, respectively. Treatment plans were generated for targets drawn in real patient CTs and head and neck phantom. We utilized beams eye view available from a commercial planning system to create beamlets having same isocenter and adjoined at the scalp surface. Then dose-deposition coefficients from those beamlets were calculated for all electron energies using MCPLAN. An in-house optimization code was then used to find the optimum weights needed from individual beamlets. Results: MeARC showed a nicely tailored dose distribution around the circular curved target on the scalp. Some hot spots were noticed and could be attributed to fields abutment problem owing to the bulging nature of electron profiles. Brain dose was shown to be at lower levels compared to photon treatment. Conclusion: MeARC was shown to be a promising modality for treating scalp cases and could be beneficial to all superficial tumors with a circular curvature.

Hot-wire chemical vapour deposition of carbon nanotubes

CSIR Research Space (South Africa)

Cummings, FR

2006-07-01

Full Text Available ablation of graphite, carbon-arc discharge and chemical vapour deposition (CVD). However, some of these techniques have been shown to be expensive due to high deposition temperatures and are not easily controllable. Recently hot-wire chemical vapour...

The electrocatalytic oxidation of carbohydrates at a nickel/carbon paper electrode fabricated by the filtered cathodic vacuum arc technique

International Nuclear Information System (INIS)

Fu, Yingyi; Wang, Tong; Su, Wen; Yu, Yanan; Hu, Jingbo

2015-01-01

The direct electrochemical behaviour of carbohydrates at a nickel/carbon paper electrode with a novel fabrication method is investigated. The investigation is used for verification the feasibility of using monosaccharides and disaccharides in the application of fuel cell. The selected monosaccharides are glucose, fructose and galactose; the disaccharides are sucrose, maltose and lactose. The modified nickel/carbon paper electrode was prepared using a filtered cathodic vacuum arc technique. The morphology image of the nickel thin film on the carbon paper surface was characterized by scanning electron microscopy (SEM). The existence of nickel was verified by X-ray photoelectron spectroscopy (XPS). The contact angle measurement was also used to characterize the modified electrode. Cyclic voltammetry (CV) was employed to evaluate the electrochemical behaviour of monosaccharides and disaccharides in an alkaline aqueous solution. The modified electrode exhibits good electrocatalytic activities towards carbohydrates. In addition, the stability of the nickel/carbon paper electrode with six sugars was also investigated. The good catalytic effects of the nickel/carbon paper electrode allow for the use of carbohydrates as fuels in fuel cell applications

Design and fabrication of broadband rugate filter

International Nuclear Information System (INIS)

Zhang Jun-Chao; Fang Ming; Shao Yu-Chuan; Jin Yun-Xia; He Hong-Bo

2012-01-01

The design and the deposition of a rugate filter for broadband applications are discussed. The bandwidth is extended by increasing the rugate period continuously with depth. The width and the smoothness of the reflection band with the distribution of the periods are investigated. The improvement of the steepness of the stopband edges and the suppression of the side lobes in the transmission zone are realized by adding two apodized rugate structures with fixed periods at the external broadband rugate filter interfaces. The rapidly alternating deposition technology is used to fabricate a rugate filter sample. The measured transmission spectrum with a reflection bandwidth of approximately 505 nm is close to that of the designed broadband rugate filter except a transmittance peak in the stopband. Based on the analysis of the cross-sectional scanning electron microscopic image of the sample, it is found that the transmission peak is most likely to be caused by the instability of the deposition rate. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

Predicting the efficiency of deposit removal during filter backwash

African Journals Online (AJOL)

Abstract. The long-term performance of granular media filters used in drinking water treatment is ultimately limited by the efficiency ... efficiency) within each set of experiments appeared to affect the efficiency of backwash in addition to the parameters varied ... anisms involved in filter cleaning (Amirtharajah, 1978; Amirth-.

Diode-rectified multiphase AC arc for the improvement of electrode erosion characteristics

Science.gov (United States)

Tanaka, Manabu; Hashizume, Taro; Saga, Koki; Matsuura, Tsugio; Watanabe, Takayuki

2017-11-01

An innovative multiphase AC arc (MPA) system was developed on the basis of a diode-rectification technique to improve electrode erosion characteristics. Conventionally, electrode erosion in AC arc is severer than that in DC arc. This originated from the fact that the required properties for the cathode and anode are different, although an AC electrode works as the cathode and the anode periodically. To solve this problem, a separation of AC electrodes into pairs of thoriated tungsten cathode and copper anode by diode-rectification was attempted. A diode-rectified multiphase AC arc (DRMPA) system was then successfully established, resulting in a drastic improvement of the erosion characteristics. The electrode erosion rate in the DRMPA was less than one-third of that in the conventional MPA without the diode rectification. In order to clarify its erosion mechanism, electrode phenomena during discharge were visualized by a high-speed camera system with appropriate band-pass filters. Fluctuation characteristics of the electrode temperature in the DRMPA were revealed.

Truncation correction for oblique filtering lines

International Nuclear Information System (INIS)

Hoppe, Stefan; Hornegger, Joachim; Lauritsch, Guenter; Dennerlein, Frank; Noo, Frederic

2008-01-01

State-of-the-art filtered backprojection (FBP) algorithms often define the filtering operation to be performed along oblique filtering lines in the detector. A limited scan field of view leads to the truncation of those filtering lines, which causes artifacts in the final reconstructed volume. In contrast to the case where filtering is performed solely along the detector rows, no methods are available for the case of oblique filtering lines. In this work, the authors present two novel truncation correction methods which effectively handle data truncation in this case. Method 1 (basic approach) handles data truncation in two successive preprocessing steps by applying a hybrid data extrapolation method, which is a combination of a water cylinder extrapolation and a Gaussian extrapolation. It is independent of any specific reconstruction algorithm. Method 2 (kink approach) uses similar concepts for data extrapolation as the basic approach but needs to be integrated into the reconstruction algorithm. Experiments are presented from simulated data of the FORBILD head phantom, acquired along a partial-circle-plus-arc trajectory. The theoretically exact M-line algorithm is used for reconstruction. Although the discussion is focused on theoretically exact algorithms, the proposed truncation correction methods can be applied to any FBP algorithm that exposes oblique filtering lines.

A Field Study on the Respiratory Deposition of the Nano-Sized Fraction of Mild and Stainless Steel Welding Fume Metals.

Science.gov (United States)

Cena, L G; Chisholm, W P; Keane, M J; Chen, B T

2015-01-01

A field study was conducted to estimate the amount of Cr, Mn, and Ni deposited in the respiratory system of 44 welders in two facilities. Each worker wore a nanoparticle respiratory deposition (NRD) sampler during gas metal arc welding (GMAW) of mild and stainless steel and flux-cored arc welding (FCAW) of mild steel. Several welders also wore side-by-side NRD samplers and closed-face filter cassettes for total particulate samples. The NRD sampler estimates the aerosol's nano-fraction deposited in the respiratory system. Mn concentrations for both welding processes ranged 2.8-199 μg/m3; Ni concentrations ranged 10-51 μg/m3; and Cr concentrations ranged 40-105 μg/m3. Cr(VI) concentrations ranged between 0.5-1.3 μg/m3. For the FCAW process the largest concentrations were reported for welders working in pairs. As a consequence this often resulted in workers being exposed to their own welding fumes and to those generated from the welding partner. Overall no correlation was found between air velocity and exposure (R2 = 0.002). The estimated percentage of the nano-fraction of Mn deposited in a mild-steel-welder's respiratory system ranged between 10 and 56%. For stainless steel welding, the NRD samplers collected 59% of the total Mn, 90% of the total Cr, and 64% of the total Ni. These results indicate that most of the Cr and more than half of the Ni and Mn in the fumes were in the fraction smaller than 300 nm.

Plasma flow in a pressure pulsed argon cascade arc

NARCIS (Netherlands)

de Haas, J.C.M.; Bol, L.; Kroesen, G.M.W.; Timmermans, C.J.; Timmermans, C.J.

1985-01-01

Flowing thermal plasmas are frequently used e . g. in welding, cutting, plasma deposition and testing materials at high temperatures . In most of the applications the geometry is complex . In the cascade arc the argon plasma flows through a straight circular channel with a constant area. The study

Filter media expansion during backwash: The effect of biological ...

African Journals Online (AJOL)

provided by the designer or that the mechanical behaviour of the media gradually changes after being placed in the filters. A number of media tests confirmed that the biological fraction of the specific deposit on the filter media (after backwashing) is relatively high – about 50% of the total specific deposit. This led to the ...

Effect of Pore Structure on Soot Deposition in Diesel Particulate Filter

Directory of Open Access Journals (Sweden)

Kazuhiro Yamamoto

2016-12-01

Full Text Available Nowadays, in the after-treatment of diesel exhaust gas, a diesel particulate filter (DPF has been used to trap nano-particles of the diesel soot. However, as there are more particles inside the filter, the pressure which corresponds to the filter backpressure increases, which worsens the fuel consumption rate, together with the abatement of the available torque. Thus, a filter with lower backpressure would be needed. To achieve this, it is necessary to utilize the information on the phenomena including both the soot transport and its removal inside the DPF, and optimize the filter substrate structure. In this paper, to obtain useful information for optimization of the filter structure, we tested seven filters with different porosities and pore sizes. The porosity and pore size were changed systematically. To consider the soot filtration, the particle-laden flow was simulated by a lattice Boltzmann method (LBM. Then, the flow field and the pressure change were discussed during the filtration process.

Technological plasma source equipped with combined system of vacuum-arc discharge initiation

International Nuclear Information System (INIS)

Sysoev, Yu.O.

2013-01-01

The construction and the operation principle of erosion plasma source with a three-stage system of vacuum-arc discharge excitation is described. As first two step was used the modified contactless start system with plasma injector, which was widely used in standard plasma sources of the ''Bulat'' systems. The operation principle of the third stage was based on the transition of glow discharge to arc discharge. Coordinated operation of three stages during various stages of coating deposition provided significant increasing of service life and reliability of the system of vacuum-arc discharge initiation and extended the functionality of the plasma source

Metal halide arc discharge lamp having short arc length

Science.gov (United States)

Muzeroll, Martin E. (Inventor)

1994-01-01

A metal halide arc discharge lamp includes a sealed light-transmissive outer jacket, a light-transmissive shroud located within the outer jacket and an arc tube assembly located within the shroud. The arc tube assembly includes an arc tube, electrodes mounted within the arc tube and a fill material for supporting an arc discharge. The electrodes have a spacing such that an electric field in a range of about 60 to 95 volts per centimeter is established between the electrodes. The diameter of the arc tube and the spacing of the electrodes are selected to provide an arc having an arc diameter to arc length ratio in a range of about 1.6 to 1.8. The fill material includes mercury, sodium iodide, scandium tri-iodide and a rare gas, and may include lithium iodide. The lamp exhibits a high color rendering index, high lumen output and high color temperature.

Photo-dynamic therapy (pdt) for skin cancer using a xenon arc lamp with interference filters

International Nuclear Information System (INIS)

Hagekyriakou, J.

2004-01-01

Full text: Phototherapy involves the production of photochemical reactions in cells by the direct action of light, including Ultra Violet, leading to biological effects, including cell death. Photo Dynamic Therapy involves the application of light, at wavelengths and intensity which has no biological effects, in combination with a photosensitizing compound, which is biologically inert in the absence of light, which once located in cells, can produce cellular damage when activated by light of certain wavelengths. The active compound produced during PDT is singlet Oxygen which has a half life of 3 microseconds. This necessitates the use of very powerful light sources, such as lasers, in order to achieve treatment delivery within a reasonable time, say minutes. Even though PDT is very effective in the treatment of skin cancer using topically applied photosensitizing drugs, the cost of powerful lasers, required to produce light in the red part of the spectrum, has been prohibitively expensive for widespread application of the above technique. A 300 Watt Xenon arc light source, with tuneable wavelength and bandwidth, used predominantly for Forensic Science applications, manufactured by Rofin Australia Pty, Ltd, has been modified by the manufacturer, boosting the power to 500 Watts. A group of Interference filters have been specifically made to facilitate irradiation at 670nm, 620nm and 600 nm, at relatively narrow bandwidth, typically 50 nm. This would provide adequate penetration of the light, for a variety of skin cancers, depending on the thickness of the lesion and the skin type involved. A relatively broad band Ultra Violet interference filter has also been inserted in the instrument for observation of Fluorescence of the lesion prior to treatment, as an indicator of photosensitizing drug uptake by the lesion involved. Patients with skin cancers such as Basal Cell Carcinoma (BCC) and Paget's Extramammary disease were treated at the Peter MacCallum Cancer Centre

Experimental study of filter cake formation on different filter media

International Nuclear Information System (INIS)

Saleem, M.

2009-01-01

Removal of particulate matter from gases generated in the process industry is important for product recovery as well as emission control. Dynamics of filtration plant depend on operating conditions. The models, that predict filter plant behaviour, involve empirical resistance parameters which are usually derived from limited experimental data and are characteristics of the filter media and filter cake (dust deposited on filter medium). Filter cake characteristics are affected by the nature of filter media, process parameters and mode of filter regeneration. Removal of dust particles from air is studied in a pilot scale jet pulsed bag filter facility resembling closely to the industrial filters. Limestone dust and ambient air are used in this study with two widely different filter media. All important parameters like pressure drop, gas flow rate, dust settling, are recorded continuously at 1s interval. The data is processed for estimation of the resistance parameters. The pressure drop rise on test filter media is compared. Results reveal that the surface of filter media has an influence on pressure drop rise (concave pressure drop rise). Similar effect is produced by partially jet pulsed filter surface. Filter behaviour is also simulated using estimated parameters and a simplified model and compared with the experimental results. Distribution of cake area load is therefore an important aspect of jet pulse cleaned bag filter modeling. Mean specific cake resistance remains nearly constant on thoroughly jet pulse cleaned membrane coated filter bags. However, the trend can not be confirmed without independent cake height and density measurements. Thus the results reveal the importance of independent measurements of cake resistance. (author)

MeCrAl coatings obtained by arc PVD and pack cementation processes on nickel base superalloys

International Nuclear Information System (INIS)

Swadzba, L.; Maciejny, A.; Formanek, B.; Mendala, B.

1997-01-01

The paper presents the results of researches on obtaining and structure of high temperature resistance coatings on superalloys. The coatings were deposited on nickel and nickel base superalloys in two stages. During the first stage, the NiCr and NiCrHf coatings were obtained by arc-PVD method. Basic technology, bias, arc current, rotation, parameters of deposition of NiCr and MeCrHf coatings were defined. The high efficiency of deposition of both single and two sources was observed. The targets were made by vacuum melting and machining. An influence of targets chemical composition on coating structure and chemical coatings composition was described. The second stage was made by pack cementation HTLA (high temperature low activity) on 1323 K chromoaluminizing process. These arc-PVD and diffusion (pack cementation) connected processes permitted to obtain MeCrAl and MeCrAlHf type of coatings. The morphology, structure and microchemical composition were characterized by scanning electron microscopy, X-ray microanalysis, energy dispersive X-ray spectroscopy and X-ray diffraction methods. (orig.)

Electric-Arc Plasma Installation for Preparing Nanodispersed Carbon Structures

International Nuclear Information System (INIS)

Stefanov, P.; Garlanov, D.; Vissokov, G.

2008-01-01

An electric-arc plasma installation operated in the hidden anode arrangement is constructed and used for the preparation of carbon nanostructures. A contracted plasma arc generated by a plasma torch using an inert gas is used as heat source. The average mass temperature of arc is higher than 10 4 K, while its power density, which is directly transferred onto the electrode (anode), is ∼ 2 kW/mm 2 . The anode contact area formed on the electrode moves against the arc by way of shifting the electrode and is hidden completely in the interior of plasma gas stream moving towards it. As a result of both the direct plasma attack and the opposite movement of streams in the hidden anode contact area, a temperature higher than 6000 K is reached. Thus, intensive vaporization takes place, which forms a saturated plasma-gas-aerosol phase of the initial material of electrode (anode). This gas phase is mixed in and carried by the plasma stream. Over that mixed plasma stream, a controlled process of quenching (fixation) is carried out by twisted turbulent fluid streams. After the fixation, the resultant carbon nano-structures are caught by a filter and collected in a bunker.

Monitoring ARC services with GangliARC

International Nuclear Information System (INIS)

Cameron, D; Karpenko, D

2012-01-01

Monitoring of Grid services is essential to provide a smooth experience for users and provide fast and easy to understand diagnostics for administrators running the services. GangliARC makes use of the widely-used Ganglia monitoring tool to present web-based graphical metrics of the ARC computing element. These include statistics of running and finished jobs, data transfer metrics, as well as showing the availability of the computing element and hardware information such as free disk space left in the ARC cache. Ganglia presents metrics as graphs of the value of the metric over time and shows an easily-digestable summary of how the system is performing, and enables quick and easy diagnosis of common problems. This paper describes how GangliARC works and shows numerous examples of how the generated data can quickly be used by an administrator to investigate problems. It also presents possibilities of combining GangliARC with other commonly-used monitoring tools such as Nagios to easily integrate ARC monitoring into the regular monitoring infrastructure of any site or computing centre.

Effects of bias voltage on the corrosion resistance of titanium nitride thin films fabricated by dynamic plasma immersion ion implantation-deposition

International Nuclear Information System (INIS)

Tian Xiubo; Fu, Ricky K. Y.; Chu, Paul K.

2002-01-01

Dynamic plasma-based thin-film deposition incorporating ion mixing and plasma immersion is an effective technique to synthesize nitride-based hard films. We have fabricated TiN films using a filtered titanium vacuum arc in a nitrogen plasma environment. A pulsed high voltage is applied to the target for a short time when the metallic arc is fired to attain simultaneous plasma deposition and ion mixing. We investigate the dependence of the corrosion resistance and interfacial structure of the treated samples on the applied voltage. Our Auger results reveal an oxygen-rich surface film due to the non-ultra-high-vacuum conditions and high affinity of oxygen to titanium. The corrosion current is reduced by two orders of magnitude comparing the sample processed at 8 kV to the untreated sample, but the 23 kV sample unexpectedly shows worse results. The pitting potential diminishes substantially although the corrosion current is similar to that observed in the 8 kV sample. The polarization test data are consistent with our scanning electron microscopy observation, corroborating the difference in the pitting distribution and appearance. This anomalous behavior is believed to be due to the change in the chemical composition as a result of high-energy ion bombardment

Arc Interference Behavior during Twin Wire Gas Metal Arc Welding Process

Directory of Open Access Journals (Sweden)

Dingjian Ye

2013-01-01

Full Text Available In order to study arc interference behavior during twin wire gas metal arc welding process, the synchronous acquisition system has been established to acquire instantaneous information of arc profile including dynamic arc length variation as well as relative voltage and current signals. The results show that after trailing arc (T-arc is added to the middle arc (M-arc in a stable welding process, the current of M arc remains unchanged while the agitation increases; the voltage of M arc has an obvious increase; the shape of M arc changes, with increasing width, length, and area; the transfer frequency of M arc droplet increases and the droplet itself becomes smaller. The wire extension length of twin arc turns out to be shorter than that of single arc welding.

Atmospheric deposition 2000. NOVA 2003; Atmosfaerisk deposition 2000. NOVA 2003

Energy Technology Data Exchange (ETDEWEB)

Ellermann, T.; Hertel, O.; Hovmand, M.F.; Kemp, K.; Skjoeth, C.A.

2001-11-01

This report presents measurements and calculations from the atmospheric part of NOVA 2003 and covers results for 2000. It summarises the main results concerning concentrations and depositions of nitrogen, phosphorus and sulphur compounds related to eutrophication and acidification. Depositions of atmospheric compounds to Danish marine waters as well as land surface are presented. Measurements: In 2000 the monitoring program consisted of eight stations where wet deposition of ammonium, nitrate, phosphate (semi quantitatively) and sulphate were measured using bulk precipitation samplers. Six of the stations had in addition measurements of atmospheric content of A, nitrogen, phosphorus, and sulphur compounds in gas and particulate phase carried out by use of filter pack samplers. Filters were analysed at the National Environmental Research Institute. Furthermore nitrogen dioxide were measured using nitrogen dioxide filter samplers and monitors. Model calculations: The measurements in the monitoring program were supplemented with model calculations of concentrations and depositions of nitrogen and sulphur compounds to Danish land surface, marine waters, fjords and bays using the ACDEP model (Atmospheric Chemistry and Deposition). The model is a so-called trajectory model and simulates the physical and chemical processes in the atmosphere using meteorological and emission data as input. The advantage of combining measurements with model calculations is that the strengths of both methods is obtained. Conclusions concerning: 1) actual concentration levels at the monitoring stations, 2) deposition at the monitoring stations, 3) seasonal variations and 4) long term trends in concentrations and depositions are mainly based on the direct measurements. These are furthermore used to validate the results of the model calculations. Calculations and conclusions concerning: 1) depositions to land surface and to the individual marine water, 2) contributions from different emission

Arc Shape Characteristics with Ultra-High-Frequency Pulsed Arc Welding

Directory of Open Access Journals (Sweden)

Mingxuan Yang

2017-01-01

Full Text Available Arc plasma possesses a constriction phenomenon with a pulsed current. The constriction is created by the Lorentz force, the radial electromagnetic force during arc welding, which determines the energy distribution of the arc plasma. Welding experiments were carried out with ultra-high-frequency pulsed arc welding (UHFP-AW. Ultra-high-speed camera observations were produced for arc surveillance. Hue-saturation-intensity (HSI image analysis was used to distinguish the regions of the arc plasma that represented the heat energy distribution. The measurement of arc regions indicated that, with an ultra-high-frequency pulsed arc, the constriction was not only within the decreased arc geometry, but also within the constricted arc core region. This can be checked by the ratio of the core region to the total area. The arc core region expanded significantly at 40 kHz at 60 A. A current level of 80 A caused a decrease in the total region of the arc. Meanwhile, the ratio of the core region to the total increased. It can be concluded that arc constriction depends on the increased area of the core region with the pulsed current (>20 kHz.

Particulate removal processes and hydraulics of porous gravel media filters

Science.gov (United States)

Minto, J. M.; Phoenix, V. R.; Dorea, C. C.; Haynes, H.; Sloan, W. T.

2013-12-01

Sustainable urban Drainage Systems (SuDS) are rapidly gaining acceptance as a low-cost tool for treating urban runoff pollutants close to source. Road runoff water in particular requires treatment due to the presence of high levels of suspended particles and heavy metals adsorbed to these particles. The aim of this research is to elucidate the particle removal processes that occur within gravel filters that have so far been considered as 'black-box' systems. Based on these findings, a better understanding will be attained on what influences gravel filter removal efficiency and how this changes throughout their design life; leading to a more rational design of this useful technology. This has been achieved by tying together three disparate research elements: tracer residence time distribution curves of filters during clogging; 3D magnetic resonance imaging (MRI) of clogging filters and computational fluid dynamics (CFD) modelling of complex filter pore networks. This research relates column average changes in particle removal efficiency and tracer residence time distributions (RTDs) due to clogging with non-invasive measurement of the spatial variability in particle deposition. The CFD modelling provides a link between observed deposition patterns, flow velocities and wall shear stresses as well as the explanations for the change in RTD with clogging and the effect on particle transport. Results show that, as a filter clogs, particles take a longer, more tortuous path through the filter. This is offset by a reduction in filter volume resulting in higher flow velocities and more rapid particle transport. Higher velocities result in higher shear stresses and the development of preferential pathways in which the velocity exceeds the deposition threshold and the overall efficiency of the filter decreases. Initial pore geometry is linked to the pattern of deposition and subsequent formation of preferential pathways. These results shed light on the 'black-box' internal

Ionized physical vapor deposition (IPVD): A review of technology and applications

International Nuclear Information System (INIS)

Helmersson, Ulf; Lattemann, Martina; Bohlmark, Johan; Ehiasarian, Arutiun P.; Gudmundsson, Jon Tomas

2006-01-01

In plasma-based deposition processing, the importance of low-energy ion bombardment during thin film growth can hardly be exaggerated. Ion bombardment is an important physical tool available to materials scientists in the design of new materials and new structures. Glow discharges and in particular, the magnetron sputtering discharge have the advantage that the ions of the discharge are abundantly available to the deposition process. However, the ion chemistry is usually dominated by the ions of the inert sputtering gas while ions of the sputtered material are rare. Over the last few years, various ionized sputtering techniques have appeared that can achieve a high degree of ionization of the sputtered atoms, often up to 50% but in some cases as much as approximately 90%. This opens a complete new perspective in the engineering and design of new thin film materials. The development and application of magnetron sputtering systems for ionized physical vapor deposition (IPVD) is reviewed. The application of a secondary discharge, inductively coupled plasma magnetron sputtering (ICP-MS) and microwave amplified magnetron sputtering, is discussed as well as the high power impulse magnetron sputtering (HIPIMS), the self-sustained sputtering (SSS) magnetron, and the hollow cathode magnetron (HCM) sputtering discharges. Furthermore, filtered arc-deposition is discussed due to its importance as an IPVD technique. Examples of the importance of the IPVD-techniques for growth of thin films with improved adhesion, improved microstructures, improved coverage of complex shaped substrates, and increased reactivity with higher deposition rate in reactive processes are reviewed

Geochemical and modal data for igneous rocks associated with epithermal mineral deposits

Science.gov (United States)

du Bray, Edward A.

2014-01-01

The purposes of this report are to (1) present available geochemical and modal data for igneous rocks associated with epithermal mineral deposits and (2) to make those data widely and readily available for subsequent, more in-depth consideration and interpretation. Epithermal precious and base-metal deposits are commonly associated with subduction-related calc-alkaline to alkaline arc magmatism as well as back-arc continental rift magmatism. These deposits form in association with compositionally diverse extrusive and intrusive igneous rocks. Temperature and depth regimes prevailing during deposit formation are highly variable. The deposits form from hydrothermal fluids that range from acidic to near-neutral pH, and they occur in a variety of structural settings. The disparate temperature, pressure, fluid chemistry, and structural controls have resulted in deposits with wide ranging characteristics. Economic geologists have employed these characteristics to develop classification schemes for epithermal deposits and to constrain the important genetic processes responsible for their formation.

The electrodynamic, thermal, and energetic character of intense sun-aligned arcs in the polar cap

International Nuclear Information System (INIS)

Valladares, C.E.; Carlson, H.C. Jr.

1991-01-01

The authors report here measurements of two intense Sun-aligned arcs. The two arcs were diagnosed on two different nights (February 26 and March 1, 1987) using the Sondre Stromfjord radar as a stand-alone diagnostic. Repeatable patterns are found in mesoscale area (order 10 3 km by 10 3 km) maps of altitude profiles for observed electron and ion gas number densities, temperatures and line-of-sight velocities, and projected mesoscale area maps of derived electric fields, Pedersen and Hall conductivities (N e , T e , T i , V, E, Σ p , Σ H ), horizontal and field-aligned currents, joule heating rate, and Poynting flux. They confirm, for the first time with continuous mesoscale area maps, that the arcs have the anticipated simple arc electrodynamics. That is, the visual and enhanced ionization signatures of the arc are produced by incoming energetic electrons carrying the outgoing current from the electric field convergence in the arc. Strong electron temperature enhancements (>2,000 K) are found as expected within the sheets of ionizing particle precipitation. Dawn to dusk decreases in the antisunward plasma flow of order 1 km s -1 , across order 100 km, correspond to peak electron densities of order 10 5 cm -3 down to altitudes as low as 120 km, and upward currents of order 1 μA m -2 . These data also lead to important implications for the physics of polar cap arcs. The high-velocity (antisunward flow on the dawnside) edge of the arc marks the location of strong persistent Joule heating driven by downward Poynting flux. The deposition rate into the atmosphere of the net electromagnetic energy well exceeds the net particle energy deposited by the ionizing energetic electron flux. This heating is a substantial source of heat into the polar thermosphere

Volumetric modulated arc therapy with flattening filter free beams for isolated abdominal/pelvic lymph nodes: report of dosimetric and early clinical results in oligometastatic patients

Directory of Open Access Journals (Sweden)

Alongi Filippo

2012-12-01

Full Text Available Abstract Background SBRT is a safe and efficient strategy to locally control multiple metastatic sites. While research in the physics domain for Flattening Filter Free Beams (FFF beams is increasing, there are few clinical data of FFF beams in clinical practice. Here we reported dosimentric and early clinical data of SBRT and FFF delivery in isolated lymph node oligometastatic patients. Methods Between October 2010 and March 2012, 34 patients were treated with SBRT for oligometastatic lymph node metastasis on a Varian TrueBeamTM treatment machine using Volumetric Modulated Arc Therapy (RapidArc. We retrospectively evaluated a total of 25 patients for isolated lymph node metastases in abdomen and/or pelvis treated with SBRT and FFF (28 treatments. Acute toxicity was recorded. Local control evaluation was scored by means of CT scan and/or PET scan. Results All dosimetric results are in line with what published for the same type of stereotactic abdominal lymph node metastases treatments and fractionation, using RapidArc. All 25 FFF SBRT patients completed the treatment. Acute gastrointestinal toxicity was minimal: one patient showed Grade 1 gastrointestinal toxicity. Three other patients presented Grade 2 toxicity. No Grade 3 or higher was recorded. All toxicities were recovered within one week. The preliminary clinical results at the median follow up of 195 days are: complete response in 12 cases, partial response in 11, stable disease in 5, with an overall response rate of 82%; no local progression was recorded. Conclusions Data of dosimetrical findings and acute toxicity are excellent for patients treated with SBRT with VMAT using FFF beams. Preliminary clinical results showed a high rate of local control in irradiated lesion. Further data and longer follow up are needed to assess late toxicity and definitive clinical outcomes.

Submarine Landslides and Mass-Transport Deposition in the Nankai fore-arc

Science.gov (United States)

Strasser, M.; Henry, P.; Kanamatsu, T.; Moe, K.; Moore, G. F.; IODP Expedition 333 Scientists

2011-12-01

Multiple lines of evidence exist for a range of sediment mass movement processes within the shallow megasplay fault zone (MSFZ) area and the adjacent slope basin in the outer fore-arc of the Nankai subduction zone, Japan. Diagnostic features observed in 3-D reflection seismic data and in cores from Integrated Ocean Drilling Program (IODP) Expedition 316 document a complex mass movement history spanning at least ˜2.87 million years. Various modes and scales of sediment remobilization can be related to the different morphotectonic settings in which they occurred and allow integration of knowledge on the spatial and temporal distribution of submarine landslides into a holistic reconstruction of the tectonostratigraphic evolution. New data from the most-recent Nankai IODP Expedition 333, which drilled and cored a Pleistocene-to-Holocene succession of the slope-basin seaward of the MSFZ, provides unprecedented details on submarine landslide processes occurring over the last Million year. The slope-basin represents the depocentre for downslope sediment transport and is characterized in 3-D reflection seismic data by several mass-transport deposits (MTDs), including an up to 180 m thick MTD. Here we present D/V Chikyu shipboard results and first post cruise results from Site C0018, including litho- bio- magneto- tephra- and stable isotope-stratigraphy, X-ray computed tomography analysis and physical properties data. Six MTDs were identified from visual core description and X-ray CT-scans. The thickest MTD is also the oldest (emplaced between 0.85 and 1.05 Ma) and it coincides with a lithological transition between a sandy turbidite sequence below, and ash-bearing hemipelagites comprising several MTDs above. Deformation styles within the MTD are heterogeneous: intervals of disturbed sediments are interbedded within intervals inferred to retain original, coherent bedding. In three occurrences the base of the MTD is defined by a shear zone within fine-grained sediments

Numerical simulation of DPF filter for selected regimes with deposited soot particles

Science.gov (United States)

Lávička, David; Kovařík, Petr

2012-04-01

For the purpose of accumulation of particulate matter from Diesel engine exhaust gas, particle filters are used (referred to as DPF or FAP filters in the automotive industry). However, the cost of these filters is quite high. As the emission limits become stricter, the requirements for PM collection are rising accordingly. Particulate matters are very dangerous for human health and these are not invisible for human eye. They can often cause various diseases of the respiratory tract, even what can cause lung cancer. Performed numerical simulations were used to analyze particle filter behavior under various operating modes. The simulations were especially focused on selected critical states of particle filter, when engine is switched to emergency regime. The aim was to prevent and avoid critical situations due the filter behavior understanding. The numerical simulations were based on experimental analysis of used diesel particle filters.

RF characteristic of MESFET on H-terminated DC arc jet CVD diamond film

International Nuclear Information System (INIS)

Liu, J.L.; Li, C.M.; Zhu, R.H.; Guo, J.C.; Chen, L.X.; Wei, J.J.; Hei, L.F.; Wang, J.J.; Feng, Z.H.; Guo, H.; Lv, F.X.

2013-01-01

Diamond has been considered to be a potential material for high-frequency and high-power electronic devices due to the excellent electrical properties. In this paper, we reported the radio frequency (RF) characteristic of metal-semiconductor field effect transistor (MESFET) on polycrystalline diamond films prepared by direct current (DC) arc jet chemical vapor deposition (CVD). First, 4 in polycrystalline diamond films were deposited by DC arc jet CVD in gas recycling mode with the deposition rate of 14 μm/h. Then the polished diamond films were treated by microwave hydrogen plasma and the 0.2 μm-gate-length MESFET was fabricated by using Au mask photolithography and electron beam (EB) lithography. The surface conductivity of the H-terminated diamond film and DC and RF performances of the MESFET were characterized. The results demonstrate that, the carrier mobility of 24.6 cm 2 /V s and the carrier density of 1.096 × 10 13 cm −2 are obtained on the surface of H-terminated diamond film. The FET shows the maximum transition frequency (f T ) of 5 GHz and the maximum oscillation frequency (f max ) of 6 GHz at V GS = −0.5 V and V DS = −8 V, which indicates that H-terminated DC arc jet CVD polycrystalline diamond is suitable for the development of high frequency devices.

Pulmón del soldador de arco Arc welder's lung

Directory of Open Access Journals (Sweden)

Luciana Molinari

2010-12-01

Full Text Available La siderosis del soldador o neumoconiosis siderótica fue descripta por Doig y McLaughlin en 1936 como una enfermedad pulmonar causada por la inhalación crónica de polvo de hierro en soldadores de arco eléctrico. Presentamos un caso de siderosis del soldador asociada a aumento de los niveles de ferritina, sin hallazgo de depósito de hierro en otros órganos y sin causas evidentes de hemosiderosis secundaria.Pneumoconiosis of electric arc welder or siderotic pneumoconiosis was described by Doig and McLaughlin in 1936 as a lung disease caused by chronic inhalation of iron fumes in electric arc welders. We present a case report of electric arc welder siderosis associated with high levels of ferritin, without findings of iron deposit in any other organ.

Quick-change filter cartridge

Science.gov (United States)

Rodgers, John C.; McFarland, Andrew R.; Ortiz, Carlos A.

1995-01-01

A quick-change filter cartridge. In sampling systems for measurement of airborne materials, a filter element is introduced into the sampled airstream such that the aerosol constituents are removed and deposited on the filter. Fragile sampling media often require support in order to prevent rupture during sampling, and careful mounting and sealing to prevent misalignment, tearing, or creasing which would allow the sampled air to bypass the filter. Additionally, handling of filter elements may introduce cross-contamination or exposure of operators to toxic materials. Moreover, it is desirable to enable the preloading of filter media into quick-change cartridges in clean laboratory environments, thereby simplifying and expediting the filter-changing process in the field. The quick-change filter cartridge of the present invention permits the application of a variety of filter media in many types of instruments and may also be used in automated systems. The cartridge includes a base through which a vacuum can be applied to draw air through the filter medium which is located on a porous filter support and held there by means of a cap which forms an airtight seal with the base. The base is also adapted for receiving absorbing media so that both particulates and gas-phase samples may be trapped for investigation, the latter downstream of the aerosol filter.

Contrasting sedimentary processes along a convergent margin: the Lesser Antilles arc system

Science.gov (United States)

Picard, Michel; Schneider, Jean-Luc; Boudon, Georges

2006-12-01

Sedimentation processes occurring in an active convergent setting are well illustrated in the Lesser Antilles island arc. The margin is related to westward subduction of the North and/or the South America plates beneath the Caribbean plate. From east to west, the arc can be subdivided into several tectono-sedimentary depositional domains: the accretionary prism, the fore-arc basin, the arc platform and inter-arc basin, and the Grenada back-arc basin. The Grenada back-arc basin, the fore-arc basin (Tobago Trough) and the accretionary prism on the east side of the volcanic arc constitute traps for particles derived from the arc platform and the South American continent. The arc is volcanically active, and provides large volumes of volcaniclastic sediments which accumulate mainly in the Grenada basin by volcaniclastic gravity flows (volcanic debris avalanches, debris flows, turbiditic flows) and minor amounts by fallout. By contrast, the eastern side of the margin is fed by ash fallout and minor volcaniclastic turbidites. In this area, the dominant component of the sediments is pelagic in origin, or derived from South America (siliciclastic turbidites). Insular shelves are the locations of carbonate sedimentation, such as large platforms which develop in the Limestone Caribbees in the northern part of the margin. Reworking of carbonate material by turbidity currents also delivers lesser amounts to eastern basins of the margin. This contrasting sedimentation on both sides of the arc platform along the margin is controlled by several interacting factors including basin morphology, volcanic productivity, wind and deep-sea current patterns, and sea-level changes. Basin morphology appears to be the most dominant factor. The western slopes of the arc platform are steeper than the eastern ones, thus favouring gravity flow processes.

Arc-based smoothing of ion beam intensity on targets

International Nuclear Information System (INIS)

Friedman, Alex

2012-01-01

By manipulating a set of ion beams upstream of a target, it is possible to arrange for a smoother deposition pattern, so as to achieve more uniform illumination of the target. A uniform energy deposition pattern is important for applications including ion-beam-driven high energy density physics and heavy-ion beam-driven inertial fusion energy (“heavy-ion fusion”). Here, we consider an approach to such smoothing that is based on rapidly “wobbling” each of the beams back and forth along a short arc-shaped path, via oscillating fields applied upstream of the final pulse compression. In this technique, uniformity is achieved in the time-averaged sense; this is sufficient provided the beam oscillation timescale is short relative to the hydrodynamic timescale of the target implosion. This work builds on two earlier concepts: elliptical beams applied to a distributed-radiator target [D. A. Callahan and M. Tabak, Phys. Plasmas 7, 2083 (2000)] and beams that are wobbled so as to trace a number of full rotations around a circular or elliptical path [R. C. Arnold et al., Nucl. Instrum. Methods 199, 557 (1982)]. Here, we describe the arc-based smoothing approach and compare it to results obtainable using an elliptical-beam prescription. In particular, we assess the potential of these approaches for minimization of azimuthal asymmetry, for the case of a ring of beams arranged on a cone. It is found that, for small numbers of beams on the ring, the arc-based smoothing approach offers superior uniformity. In contrast with the full-rotation approach, arc-based smoothing remains usable when the geometry precludes wobbling the beams around a full circle, e.g., for the X-target [E. Henestroza, B. G. Logan, and L. J. Perkins, Phys. Plasmas 18, 032702 (2011)] and some classes of distributed-radiator targets.

Operation and Applications of the Boron Cathodic Arc Ion Source

International Nuclear Information System (INIS)

Williams, J. M.; Freeman, J. H.; Klepper, C. C.; Chivers, D. J.; Hazelton, R. C.

2008-01-01

The boron cathodic arc ion source has been developed with a view to several applications, particularly the problem of shallow junction doping in semiconductors. Research has included not only development and operation of the boron cathode, but other cathode materials as well. Applications have included a large deposition directed toward development of a neutron detector and another deposition for an orthopedic coating, as well as the shallow ion implantation function. Operational experience is described and information pertinent to commercial operation, extracted from these experiments, is presented.

Improving the technology of deposition using strip electrode

Directory of Open Access Journals (Sweden)

Сергій Володимирович Гулаков

2017-07-01

Full Text Available The behavior of the arc at the strip electrode tip is studied. It is shown that the arc is moving along the electrode tip due to periodic short-circuits of the arc gap. Thus, a new arc is excited at the point where short circuit occurred after a conductive bridge formed by molten metal is vanished due to a high welding current. This leads to an increase in the probability of defect formation in the deposited layer of workpiece under treatment. To improve deposited layer quality, it is suggested to identify the moments of short-circuits of the electrode to the base metal and to discharge the pre-charged capacitorat these instants, connecting it between the electrode and the product. High discharge current pulse speeds up the destruction of the molten metal bridge between electrode tip and workpiece, thus lowering the time needed for arc re-ignition and improving depostion process stability. A special automated equipment has been developed to implement this process. Capacitor discharge is done using power thyristor with series-connected inductance for limiting discharging current rate of rise and for limiting discharge current peak value such that it is not impairing thyristor reliability. The pre-charging of the capacitor is done by an auxiliary power supply. Several thyristor-capacitor networks can be used in parallel to allow for multiple current pulses mode and to reduce RMS currents in capacitors

In Vitro Analysis of Electrophoretic Deposited Fluoridated Hydroxyapatite Coating on Micro-arc Oxidized AZ91 Magnesium Alloy for Biomaterials Applications

Science.gov (United States)

Razavi, Mehdi; Fathi, Mohammadhossein; Savabi, Omid; Vashaee, Daryoosh; Tayebi, Lobat

2015-03-01

Magnesium (Mg) alloys have been recently introduced as a biodegradable implant for orthopedic applications. However, their fast corrosion, low bioactivity, and mechanical integrity have limited their clinical applications. The main aim of this research was to improve such properties of the AZ91 Mg alloy through surface modifications. For this purpose, nanostructured fluoridated hydroxyapatite (FHA) was coated on AZ91 Mg alloy by micro-arc oxidation and electrophoretic deposition method. The coated alloy was characterized through scanning electron microscopy, transmission electron microscopy, X-ray diffraction, in vitro corrosion tests, mechanical tests, and cytocompatibility evaluation. The results confirmed the improvement of the corrosion resistance, in vitro bioactivity, mechanical integrity, and the cytocompatibility of the coated Mg alloy. Therefore, the nanostructured FHA coating can offer a promising way to improve the properties of the Mg alloy for orthopedic applications.

High-Power 365 nm UV LED Mercury Arc Lamp Replacement for Photochemistry and Chemical Photolithography

OpenAIRE

H?lz, K.; Lietard, J.; Somoza, M. M.

2016-01-01

Ultraviolet light emitting diodes (UV LEDs) have become widespread in chemical research as highly efficient light sources for photochemistry and photopolymerization. However, in more complex experimental setups requiring highly concentrated light and highly spatially resolved patterning of the light, high-pressure mercury arc lamps are still widely used because they emit intense UV light from a compact arc volume that can be efficiently coupled into optical systems. Advances in the deposition...

Compositional Variations of Paleogene and Neogene Tephra From the Northern Izu-Bonin-Mariana Arc

Science.gov (United States)

Tepley, F. J., III; Barth, A. P.; Brandl, P. A.; Hickey-Vargas, R.; Jiang, F.; Kanayama, K.; Kusano, Y.; Li, H.; Marsaglia, K. M.; McCarthy, A.; Meffre, S.; Savov, I. P.; Yogodzinski, G. M.

2014-12-01

A primary objective of IODP Expedition 351 was to evaluate arc initiation processes of the Izu-Bonin-Mariana (IBM) volcanic arc and its compositional evolution through time. To this end, a single thick section of sediment overlying oceanic crust was cored in the Amami Sankaku Basin where a complete sediment record of arc inception and evolution is preserved. This sediment record includes ash and pyroclasts, deposited in fore-arc, arc, and back-arc settings, likely associated with both the ~49-25 Ma emergent IBM volcanic arc and the evolving Ryukyu-Kyushu volcanic arc. Our goal was to assess the major element evolution of the nascent and evolving IBM system using the temporally constrained record of the early and developing system. In all, more than 100 ash and tuff layers, and pyroclastic fragments were selected from temporally resolved portions of the core, and from representative fractions of the overall core ("core catcher"). The samples were prepared to determine major and minor element compositions via electron microprobe analyses. This ash and pyroclast record will allow us to 1) resolve the Paleogene evolutionary history of the northern IBM arc in greater detail; 2) determine compositional variations of this portion of the IBM arc through time; 3) compare the acquired data to an extensive whole rock and tephra dataset from other segments of the IBM arc; 4) test hypotheses of northern IBM arc evolution and the involvement of different source reservoirs; and 5) mark important stratigraphic markers associated with the Neogene volcanic history of the adjacent evolving Ryukyu-Kyushu arc.

On arc efficiency in gas tungsten arc welding

Directory of Open Access Journals (Sweden)

Nils Stenbacka

2013-12-01

Full Text Available The aim of this study was to review the literature on published arc efficiency values for GTAW and, if possible, propose a narrower band. Articles between the years 1955 - 2011 have been found. Published arc efficiency values for GTAW DCEN show to lie on a wide range, between 0.36 to 0.90. Only a few studies covered DCEP - direct current electrode positive and AC current. Specific information about the reproducibility in calorimetric studies as well as in modeling and simulation studies (considering that both random and systematic errors are small was scarce. An estimate of the average arc efficiency value for GTAW DCEN indicates that it should be about 0.77. It indicates anyway that the GTAW process with DCEN is an efficient welding method. The arc efficiency is reduced when the arc length is increased. On the other hand, there are conflicting results in the literature as to the influence of arc current and travel speed.

Jurassic ash-flow sheets, calderas, and related intrusions of the Cordilleran volcanic arc in southeastern Arizona: implications for regional tectonics and ore deposits

Science.gov (United States)

Lipman, P.W.; Hagstrum, J.T.

1992-01-01

Volcanologic, petrologic, and paleomagnetic studies of widespread Jurassic ash-flow sheets in the Huachuca-southern Dragoon Mountains area have led to identification of four large source calderas and associated comagnetic intracaldera intrusions. Stratigraphic, facies, and contact features of the caldera-related tuffs also provide constraints on the locations, lateral displacements, and very existence for some major northwest-trending faults and inferred regional thrusts in southeastern Arizona. Silicic alkalic compositions of the Jurassic caldera-related, ash-flow tuffs; bimodal associated mafic magmatism; and interstratified coarse sedimentary deposits provide evidence for synvolcanic extension and rifting within the Cordilleran magmatic arc. Gold-copper mineralization is associated with subvolcanic intrusions at several of the Jurassic calderas. -from Authors

Comparison of hydrothermal alteration patterns associated with porphyry Cu deposits hosted by granitoids and intermediate-mafic volcanic rocks, Kerman Magmatic Arc, Iran: Application of geological, mineralogical and remote sensing data

Science.gov (United States)

Yousefi, Seyyed Jabber; Ranjbar, Hojjatollah; Alirezaei, Saeed; Dargahi, Sara; Lentz, David R.

2018-06-01

The southern section of the Cenozoic Urumieh-Dokhtar Magmatic Arc (UDMA) of Iran, known as Kerman Magmatic Arc (KMA) or Kerman copper belt, is a major host to porphyry Cu ± Mo ± Au deposits, collectively known as PCDs. In this study, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data and spectral angle mapper (SAM) method, combined with field data, mineralogical studies, and spectral analysis are used to determine hydrothermal alteration patterns related to PCDs in the KMA. Gossans developed over some of these porphyry type deposits were mapped using Landsat 8 data. In the NKMA gossans are more developed than in the SKMA due to comparatively lower rate of erosion. The hydrothermal alteration pattern mapped by ASTER data were evaluated using mineralogical and spectral data. ASTER data proved to be useful for mapping the hydrothermal alteration in this semi-arid type of climate. Also Landsat 8 was useful for mapping the iron oxide minerals in the gossans that are associated with the porphyry copper deposits. Our multidisciplinary approach indicates that unlike the PCDs in the northern KMA that are associated with distinct and widespread propylitic alteration, those in the granitoid country rocks lack propylitic alteration or the alteration is only weakly and irregularly developed. The porphyry systems in southern KMA are further distinguished by development of quartz-rich phyllic alteration zones in the outer parts of the PCDs that could be mapped using remote sensing data. Consideration of variations in alteration patterns and specific alteration assemblages are critical in regional exploration for PCDs.

Ceramic fiber reinforced filter

Science.gov (United States)

Stinton, David P.; McLaughlin, Jerry C.; Lowden, Richard A.

1991-01-01

A filter for removing particulate matter from high temperature flowing fluids, and in particular gases, that is reinforced with ceramic fibers. The filter has a ceramic base fiber material in the form of a fabric, felt, paper of the like, with the refractory fibers thereof coated with a thin layer of a protective and bonding refractory applied by chemical vapor deposition techniques. This coating causes each fiber to be physically joined to adjoining fibers so as to prevent movement of the fibers during use and to increase the strength and toughness of the composite filter. Further, the coating can be selected to minimize any reactions between the constituents of the fluids and the fibers. A description is given of the formation of a composite filter using a felt preform of commercial silicon carbide fibers together with the coating of these fibers with pure silicon carbide. Filter efficiency approaching 100% has been demonstrated with these filters. The fiber base material is alternately made from aluminosilicate fibers, zirconia fibers and alumina fibers. Coating with Al.sub.2 O.sub.3 is also described. Advanced configurations for the composite filter are suggested.

High Pass Filtering of Satellite Altimeter Data,

Science.gov (United States)

1982-10-01

bathymetry [7] and filtered data tracks (N = 3, X = 200 km) near the Clipperton Fracture Zone just East of the Christmas Island Ridge. Along the multiple...We also notice a negative signature associated with the Clipperton Fracture Zone and extending over all the tracks. It may indicate a trough covered...in Mid-Pacific Seamount Province..Mid-Iat tic and near the Western Clipperton Fracture Zone respectively. These charts arc to he overlaid by Figures

Scandium/carbon filters for soft x rays

NARCIS (Netherlands)

Artioukov, IA; Kasyanov, YS; Kopylets, IA; Pershin, YP; Romanova, SA

2003-01-01

This Note deals with thin-film soft x-ray filters for operation at the wavelengths near carbon K edge (similar to4.5 nm). The filters were fabricated by magnetron sputtering deposition of thin layers of scandium (total thickness 0.1-0.2 mum) onto films of polypropylene (thickness 1.5 mum) and

On a multiscale approach for filter efficiency simulations

KAUST Repository

Iliev, Oleg

2014-07-01

Filtration in general, and the dead end depth filtration of solid particles out of fluid in particular, is intrinsic multiscale problem. The deposition (capturing of particles) essentially depends on local velocity, on microgeometry (pore scale geometry) of the filtering medium and on the diameter distribution of the particles. The deposited (captured) particles change the microstructure of the porous media what leads to change of permeability. The changed permeability directly influences the velocity field and pressure distribution inside the filter element. To close the loop, we mention that the velocity influences the transport and deposition of particles. In certain cases one can evaluate the filtration efficiency considering only microscale or only macroscale models, but in general an accurate prediction of the filtration efficiency requires multiscale models and algorithms. This paper discusses the single scale and the multiscale models, and presents a fractional time step discretization algorithm for the multiscale problem. The velocity within the filter element is computed at macroscale, and is used as input for the solution of microscale problems at selected locations of the porous medium. The microscale problem is solved with respect to transport and capturing of individual particles, and its solution is postprocessed to provide permeability values for macroscale computations. Results from computational experiments with an oil filter are presented and discussed.

Annealing effect of thermal spike in MgO thin film prepared by cathodic vacuum arc deposition

Energy Technology Data Exchange (ETDEWEB)

Zhu, Daoyun, E-mail: zhudy@gdut.edu.cn [Experiment Teaching Department, Guangdong University of Technology, Guangzhou 510006 (China); State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Zhao, Shoubai [School of Physics and Electronic Engineering, Guangzhou University, Guangzhou 510400 (China); Zheng, Changxi; Chen, Dihu [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); He, Zhenhui, E-mail: stshzh@mail.sysu.edu.cn [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China)

2013-12-16

MgO films were prepared by using pulsed cathodic vacuum arc deposition technique. The substrate bias voltage was in the range of −150 to −750 V. Film structure was investigated by X-ray diffraction (XRD). The annealing effect of thermal spike produced by the impacting of energetic ions was analyzed. The calculated results showed that the lifetime of a thermal spike generated by an energetic ion with the energy of 150 eV was less than one picosecond and it was sufficient to allow Mg{sup 2+} or O{sup 2-} to move one bond length to satisfy the intrinsic stress relief in the affected volume. The MgO(200) lattice spacings of the films deposited at different bias voltages were all larger than the ideal value of 2.1056 Å. As the bias amplitude increased the lattice spacing decreased, which indicated that the compressive stress in the film was partially relieved with increasing impacting ion energy. The stress relief also could be reflected from the film orientation with bias voltage. The biaxial elastic modulus for MgO(100), MgO(110) and MgO(111) planes were calculated and they were M{sub (100)} = 199 GPa, M{sub (110)} = 335 GPa and M{sub (111)} = 340 GPa, respectively. The M values indicated that the preferred orientation will be MgO(200) due to the minimum energy configuration when the lattice strain was large. It was confirmed by the XRD results in our experiments. - Highlights: • MgO thin films with preferred orientation were obtained by CVAD technique. • Annealing effect of a thermal spike in MgO film was discussed. • Lattice spacing of MgO film decreased with the increase of bias voltage. • Film preferred orientation changed from (200) to (220) as the bias voltage increased.

A study of uniformity of elements deposition on glass fiber filters after collection of airborne particulate matter (PM-10), using a high-volume sampler.

Science.gov (United States)

Marrero, Julieta; Rebagliati, Raúl Jiménez; Gómez, Darío; Smichowski, Patricia

2005-12-15

A study was conducted to evaluate the homogeneity of the distribution of metals and metalloids deposited on glass fiber filters collected using a high-volume sampler equipped with a PM-10 sampling head. The airborne particulate matter (APM)-loaded glass fiber filters (with an active surface of about 500cm(2)) were weighed and then each filter was cut in five small discs of 6.5cm of diameter. Each disk was mineralized by acid-assisted microwave (MW) digestion using a mixture of nitric, perchloric and hydrofluoric acids. Analysis was performed by axial view inductively coupled plasma optical emission spectrometry (ICP OES) and the elements considered were: Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Sb, Ti and V. The validation of the procedure was performed by the analysis of the standard reference material NIST 1648, urban particulate matter. As a way of comparing the possible variability in trace elements distribution in a particular filter, the mean concentration for each element over the five positions (discs) was calculated and each element concentration was normalized to this mean value. Scatter plots of the normalized concentrations were examined for all elements and all sub-samples. We considered that an element was homogeneously distributed if its normalized concentrations in the 45 sub-samples were within +/-15% of the mean value ranging between 0.85 and 1.15. The study demonstrated that the 12 elements tested showed different distribution pattern. Aluminium, Cu and V showed the most homogeneous pattern while Cd and Ni exhibited the largest departures from the mean value in 13 out of the 45 discs analyzed. No preferential deposition was noticed in any sub-sample.

Chemical vapour deposition of carbon nanotubes

CSIR Research Space (South Africa)

Arendse, CJ

2006-02-01

Full Text Available , effective, more versatile and easily scalable to large substrate sizes. In this paper, we present a design of the hot-wire CVD system constructed at the CSIR for the deposition of CNTs. Additionally, we will report on the structure of CNTs deposited... exhibit exceptional chemical and physical properties related to toughness, chemical inertness, magnetism, and electrical and thermal conductivity. A variety of preparation methods to synthesise CNTs are known, e.g. carbon-arc discharge, laser ablation...

Influence of Deposition Conditions on Fatigue Properties of Martensitic Stainless Steel with Tin Film Coated by Arc Ion Plating Method

Science.gov (United States)

Fukui, Satoshi; Yonekura, Daisuke; Murakami, Ri-Ichi

The surface properties like roughness etc. strongly influence the fatigue strength of high-tensile steel. To investigate the effect of surface condition and TiN coating on the fatigue strength of high-strength steel, four-point bending fatigue tests were carried out for martensitic stainless steel with TiN film coated using arc ion plating (AIP) method. This study, using samples that had been polished under several size of grind particle, examines the influence of pre-coating treatment on fatigue properties. A 2-µm-thick TiN film was deposited onto the substrate under three kinds of polishing condition. The difference of the hardness originated in the residual stress or thin deformation layer where the difference of the size of grinding particle of the surface polishing. And it leads the transformation of the interface of the substrate and the TiN film and improves fatigue limit.

Protection system for 11kV network using arc noise

International Nuclear Information System (INIS)

Burdi, M.K.; Memon, A.S.; Shaikh, S.A.

2000-01-01

Extensive research work is being done on protecting devices for 11KV network using arc noise and fault noise frequencies in relay to operate a circuit breaker; The relay works on the principle of detecting fault and extracting voltage signal output from the noise frequencies across filter. The voltage development without amplification, is enough to operate the circuit breaker. Sensitivity of the circuit breaker. In this paper design, operation and application of the relay are described. (author)

Alleviation of process-induced cracking of the antireflection TiN coating (ARC-TiN) in Al-Cu and Al-Cu-Si films

CERN Document Server

Peng, Y C; Yang, Y R; Hsieh, W Y; Hsieh, Y F

1999-01-01

The alleviation of cracking of the TiN-ARC layer on Al-Cu and Al-Cu-Si films after the development process has been achieved. For the TiN-ARC/Al-Cu system, the stress-induced defects decreased with increasing TiN-ARC layer thickness. In contrast, for the TiN-ARC/Al-Cu-Si system, Si nodules formed during cooling, thereby inducing poor coverage with high aspect-ratio holes. As a result, the photoresist developer penetrated through the films. Chemical vapor deposition of TiN-ARC or predeposition of a Ti Interposing layer was used to eliminate the formation of Si nodules.

Clustering of arc volcanoes caused by temperature perturbations in the back-arc mantle.

Science.gov (United States)

Lee, Changyeol; Wada, Ikuko

2017-06-29

Clustering of arc volcanoes in subduction zones indicates along-arc variation in the physical condition of the underlying mantle where majority of arc magmas are generated. The sub-arc mantle is brought in from the back-arc largely by slab-driven mantle wedge flow. Dynamic processes in the back-arc, such as small-scale mantle convection, are likely to cause lateral variations in the back-arc mantle temperature. Here we use a simple three-dimensional numerical model to quantify the effects of back-arc temperature perturbations on the mantle wedge flow pattern and sub-arc mantle temperature. Our model calculations show that relatively small temperature perturbations in the back-arc result in vigorous inflow of hotter mantle and subdued inflow of colder mantle beneath the arc due to the temperature dependence of the mantle viscosity. This causes a three-dimensional mantle flow pattern that amplifies the along-arc variations in the sub-arc mantle temperature, providing a simple mechanism for volcano clustering.

Investigation of plasma arc welding as a method for the additive manufacturing of titanium-(6)aluminum-(4)vanadium alloy components

Science.gov (United States)

Stavinoha, Joe N.

The process of producing near net-shape components by material deposition is known as additive manufacturing. All additive manufacturing processes are based on the addition of material with the main driving forces being cost reduction and flexibility in both manufacturing and product design. With wire metal deposition, metal is deposited as beads side-by-side and layer-by-layer in a desired pattern to build a complete component or add features on a part. There are minimal waste products, low consumables, and an efficient use of energy and feedstock associated with additive manufacturing processes. Titanium and titanium alloys are useful engineering materials that possess an extraordinary combination of properties. Some of the properties that make titanium advantageous for structural applications are its high strength-to-weight ratio, low density, low coefficient of thermal expansion, and good corrosion resistance. The most commonly used titanium alloy, Ti-6Al-4V, is typically used in aerospace applications, pressure vessels, aircraft gas turbine disks, cases and compressor blades, and surgical implants. Because of the high material prices associated with titanium alloys, the production of near net-shape components by additive manufacturing is an attractive option for the manufacturing of Ti-6Al-4V alloy components. In this thesis, the manufacturing of cylindrical Ti-6Al-4V alloy specimens by wire metal deposition utilizing the plasma arc welding process was demonstrated. Plasma arc welding is a cost effective additive manufacturing technique when compared to other current additive manufacturing methods such as laser beam welding and electron beam welding. Plasma arc welding is considered a high-energy-density welding processes which is desirable for the successful welding of titanium. Metal deposition was performed using a constant current plasma arc welding power supply, flow-purged welding chamber, argon shielding and orifice gas, ERTi-5 filler metal, and Ti-6Al

Surface PIXE analysis of phosphorus in a thin SiO2 (P, B) CVD layer deposited onto Si substrate

International Nuclear Information System (INIS)

Roumie, M.; Nsouli, B.

2001-01-01

Phosphorus determination, at level of percent, in Si matrix is not an easy analytical task. The analyzed materials arc Borophosphosilicate glass which are an important component of silicon based semiconductor technology. It's a thin SiO2 layer (400 nm) doped with boron and phosphorus using, in general, CVD (Chemical Vapor Deposition) process, in order to improve its plasticity, and deposited onto Si substrate. Therefore, the mechanical behaviour of the CVD SiO2 (P, B) layer is very sensitive to the phosphorus concentration. In this work we explore the capability of FIXE (Particle Induced X-ray Emission) to monitor a rapid and accurate quantification of P which is usually very low in such materials (few percent of the thin CVD layer deposited onto a silicon substrate). A systematic study is undertaken using Proton (0.5-3 MeV energy) and helium (1-3 MeV energy) beams, different thickness of X-ray absorber (131 and 146 μm of Kapton filter) and different tilting angles (0,45,60 and 80 deg.). The optimized measurement conditions should improve the P signal detection comparing to the Si and Background ones

Constraints on the source of Cu in a submarine magmatic-hydrothermal system, Brothers volcano, Kermadec island arc

Science.gov (United States)

Keith, Manuel; Haase, Karsten M.; Klemd, Reiner; Smith, Daniel J.; Schwarz-Schampera, Ulrich; Bach, Wolfgang

2018-05-01

Most magmatic-hydrothermal Cu deposits are genetically linked to arc magmas. However, most continental or oceanic arc magmas are barren, and hence new methods have to be developed to distinguish between barren and mineralised arc systems. Source composition, melting conditions, the timing of S saturation and an initial chalcophile element-enrichment represent important parameters that control the potential of a subduction setting to host an economically valuable deposit. Brothers volcano in the Kermadec island arc is one of the best-studied examples of arc-related submarine magmatic-hydrothermal activity. This study, for the first time, compares the chemical and mineralogical composition of the Brothers seafloor massive sulphides and the associated dacitic to rhyolitic lavas that host the hydrothermal system. Incompatible trace element ratios, such as La/Sm and Ce/Pb, indicate that the basaltic melts from L'Esperance volcano may represent a parental analogue to the more evolved Brothers lavas. Copper-rich magmatic sulphides (Cu > 2 wt%) identified in fresh volcanic glass and phenocryst phases, such as clinopyroxene, plagioclase and Fe-Ti oxide suggest that the surrounding lavas that host the Brothers hydrothermal system represent a potential Cu source for the sulphide ores at the seafloor. Thermodynamic calculations reveal that the Brothers melts reached volatile saturation during their evolution. Melt inclusion data and the occurrence of sulphides along vesicle margins indicate that an exsolving volatile phase extracted Cu from the silicate melt and probably contributed it to the overlying hydrothermal system. Hence, the formation of the Cu-rich seafloor massive sulphides (up to 35.6 wt%) is probably due to the contribution of Cu from a bimodal source including wall rock leaching and magmatic degassing, in a mineralisation style that is hybrid between Cyprus-type volcanic-hosted massive sulphide and subaerial epithermal-porphyry deposits.

Fuel filter device, particularly for Diesel fuel. Kraftstoffiltriereinrichtung, insbesondere fuer Dieselkraftstoff

Energy Technology Data Exchange (ETDEWEB)

Copeland, S.B.

1981-01-22

The purpose of the invention is to describe a fuel filter device, particularly for Diesel fuel, where dirt is deposited in the expansion chamber without causing turbulence. In order to solve the problem the device is characterized by the fact that there are radial fins, which guide the fuel in laminar flow. These fins ensure that dirt can be deposited in the expansion chamber without causing turbulence. In order to avoid stuttering of the internal combustion engine due to the formation of air pockets in the filter, suitable inlets and outlets are provided for the filter chamber.

IODP Expedition 351 Lithostratigraphy: Volcaniclastic Record of Izu-Bonin-Mariana (IBM) Arc Initiation

Science.gov (United States)

Barth, A. P.; Brandl, P. A.; Li, H.; Hickey-Vargas, R.; Jiang, F.; Kanayama, K.; Kusano, Y.; Marsaglia, K. M.; McCarthy, A.; Meffre, S.; Savov, I. P.; Tepley, F. J., III; Yogodzinski, G. M.

2014-12-01

The destruction of lithospheric plates by subduction is a fundamentally important process leading to arc magmatism and the creation of continental crust, yet subduction initiation and early magmatic arc evolution remain poorly understood. For many arc systems, onset of arc volcanism and early evolution are obscured by metamorphism or the record is deeply buried; however, initial products of arc systems may be preserved in forearc and backarc sedimentary records. IODP Expedition 351 recovered this history from the dispersed ash and pyroclast record in the proximal rear-arc of the northern IBM system west of the Kyushu-Palau Ridge. Drilling at Site U1438 in the Amami Sankaku Basin recovered a thick volcaniclastic record of subduction initiation and the early evolution of the Izu-Bonin Arc. A 160-m thick section of Neogene sediment overlies 1.3 kilometers of Paleogene volcaniclastic rocks with andesitic average composition; this volcaniclastic section was deposited on mafic volcanic basement rocks. The thin upper sediment layer is primarily terrigenous, biogenic and volcaniclastic mud and ooze with interspersed ash layers. The underlying Eocene to Oligocene volcaniclastic rocks are 33% tuffaceous mudstone, 61% tuffaceous sandstone, and 6% conglomerate with volcanic and rare sedimentary clasts commonly up to pebble and rarely to cobble size. The clastic section is characterized by repetitive conglomerate and sandstone-dominated intervals with intervening mudstone-dominated intervals, reflecting waxing and waning of coarse arc-derived sediment inputs through time. Volcanic lithic clasts in sandstones and conglomerates range from basalt to rhyolite in composition and include well-preserved pumice, reflecting a lithologically diverse and compositionally variable arc volcanic source.

ALVIN-SeaBeam studies of the Sumisu Rift, Izu-Bonin arc

Science.gov (United States)

Taylor, B.; Brown, G.; Fryer, P.; Gill, J. B.; Hochstaedter, A. G.; Hotta, H.; Langmuir, C. H.; Leinen, M.; Nishimura, A.; Urabe, T.

1990-10-01

Bimodal volcanism, normal faulting, rapid sedimentation, and hydrothermal circulation characterize the rifting of the Izu-Bonin arc at 31°N. Analysis of the zigzag pattern, in plan view, of the normal faults that bound Sumisu Rift indicates that the extension direction (080° ± 10°) is orthogonal to the regional trend of the volcanic front. Normal faults divide the rift into an inner rift on the arc side, which is the locus for maximum subsidence and sedimentation, and an outer rift further west. Transfer zones that link opposing master faults and/or rift flank uplifts further subdivide the rift into three segments along strike. Volcanism is concentrated along the ENE-trending transfer zone which separates the northern and central rift segments. The differential motion across the zone is accommodated by interdigitating north-trending normal faults rather than by ENE-trending oblique-slip faults. Volcanism in the outer rift has built 50-700 m high edifices without summit craters whereas in the inner rift it has formed two multi-vent en echelon ridges (the largest is 600 m high and 16 km long). The volcanism is dominantly basaltic, with compositions reflecting mantle sources little influenced by arc components. An elongate rhyolite dome and low-temperature hydrothermal deposits occur at the en echelon step in the larger ridge, which is located at the intersection of the transfer zone with the inner rift. The chimneys, veins, and crusts are composed of silica, barite and iron oxide, and are of similar composition to the ferruginous chert that mantles the Kuroko deposits. A 1.2-km transect of seven ALVIN heat flow measurements at 30°48.5'N showed that the inner-rift-bounding faults may serve as water recharge zones, but that they are not necessarily areas of focussed hydrothermal outflow, which instead occurs through the thick basin sediments. The rift basin and arc margin sediments are probably dominated by permeable rhyolitic pumice and ash erupted from submarine

Corrosion behaviour of Arc-PVD coatings and hybrid systems

International Nuclear Information System (INIS)

Reichel, K.

1992-01-01

To achieve a comprehensive protective effect against corrosion and wear stresses, coating systems are increasingly being developed, in which there is a separation of the tasks of the coating materials regarding the protective effect. On the one hand, pure PVD coating systems are used, on the other hand hybrid coatings are examined, where galvanic processes are combined with PVD technique. The results of experiments introduced in this article were determined on Arc-PVD coatings. By this process, titanium nitride and chromium nitride coatings are both deposited directly on the basic material and are also deposited as combination coatings of Ti/TiN and chemical nickel/TiN. (orig.) [de

Critical Length Criterion and the Arc Chain Model for Calculating the Arcing Time of the Secondary Arc Related to AC Transmission Lines

International Nuclear Information System (INIS)

Cong Haoxi; Li Qingmin; Xing Jinyuan; Li Jinsong; Chen Qiang

2015-01-01

The prompt extinction of the secondary arc is critical to the single-phase reclosing of AC transmission lines, including half-wavelength power transmission lines. In this paper, a low-voltage physical experimental platform was established and the motion process of the secondary arc was recorded by a high-speed camera. It was found that the arcing time of the secondary arc rendered a close relationship with its arc length. Through the input and output power energy analysis of the secondary arc, a new critical length criterion for the arcing time was proposed. The arc chain model was then adopted to calculate the arcing time with both the traditional and the proposed critical length criteria, and the simulation results were compared with the experimental data. The study showed that the arcing time calculated from the new critical length criterion gave more accurate results, which can provide a reliable criterion in term of arcing time for modeling and simulation of the secondary arc related with power transmission lines. (paper)

Catalytic property of an indium-deposited powder-type material containing silicon and its dependence on the dose of indium nano-particles irradiated by a pulse arc plasma process

Directory of Open Access Journals (Sweden)

Satoru Yoshimura

2017-06-01

Full Text Available Indium nano-particle irradiations onto zeolite powders were carried out using a pulse arc plasma source system. X-ray photoelectron spectroscopic and scanning electron microscopic studies of an indium irradiated zeolite sample revealed that indium nano-particles were successfully deposited on the sample. Besides, the sample was found to be capable of catalyzing an organic chemical reaction (i.e., Friedel-Crafts alkylation. Then, we examined whether or not the catalytic ability depends on the irradiated indium dose, having established the optimal indium dose for inducing the catalytic effect.

Multi-Canister overpack internal HEPA filters

International Nuclear Information System (INIS)

SMITH, K.E.

1998-01-01

The rationale for locating a filter assembly inside each Multi-Canister Overpack (MCO) rather than include the filter in the Cold Vacuum Drying (CVD) process piping system was to eliminate the potential for contamination to the operators, processing equipment, and the MCO. The internal HEPA filters provide essential protection to facility workers from alpha contamination, both external skin contamination and potential internal depositions. Filters installed in the CVD process piping cannot mitigate potential contamination when breaking the process piping connections. Experience with K-Basin material has shown that even an extremely small release can result in personnel contamination and costly schedule disruptions to perform equipment and facility decontamination. Incorporating the filter function internal to the MCO rather than external is consistent with ALARA requirements of 10 CFR 835. Based on the above, the SNF Project position is to retain the internal HEPA filters in the MCO design

Collection of aerosols in high efficiency particulate air filters

International Nuclear Information System (INIS)

Pratt, R.P.; Green, B.L.

1987-01-01

The investigation of the performance of HEPA filters of both minipleat and conventional deep pleat designs has continued at Harwell. Samples of filters from several manufacturers have been tested against the UKAEA/BNF plc filter purchasing specification. No unexpected problems have come to light in these tests, apart from some evidence to suggest that although meeting the specification minipleat filters are inherently weaker in burst strength terms than conventional filters. In addition tests have been carried out to investigate the dust loading versus pressure drop characteristics of both designs of filters using a range of test dusts - ASHRAE dust, carbon black, BS 2831 No. 2 test dust and sodium chloride. In parallel with laboratory test work a more fundamental study on the effects of geometric arrangement of filter media within the filter frame has been carried out on behalf of the UKAEA by Loughborough University. The results of this study has been the development of a mathematical model to predict the dust load versus pressure drop characteristic as a function of filter media geometry. This has produced good agreement with laboratory test results using a challenge aerosol in the 1-5 μm size range. Further observations have been made to enhance understanding of the deposition of aerosols within the filter structure. The observations suggest that the major influence on dust loading is the depth of material collected in the flow channel as a surface deposition, and this explains the relatively poor performance of the minipleat design of filter

Arc saw development report

International Nuclear Information System (INIS)

Deichelbohrer, P.R.; Beitel, G.A.

1981-01-01

The arc saw is one of the key components of the Contaminated Equipment Volume Reduction (CEVR) Program. This report describes the progress of the arc saw from its inception to its current developmental status. History of the arc saw and early contributors are discussed. Particular features of the arc saw and their advantages for CEVR are detailed. Development of the arc saw including theory of operation, pertinent experimental results, plans for the large arc saw and advanced control systems are covered. Associated topics such as potential applications for the arc saw and other arc saw installations in the world is also touched upon

The effect of flux on properties of weld in submerged arc welding with filler metal

International Nuclear Information System (INIS)

Fattahpour, Iran.

1984-01-01

In the submerged-arc welding, the electrode wire is shielded by a blanket of granular fusible material called a flux. This granular material, flux, must ensure the deposition of weld metal of given chemical composition and specified mechanical properties. The flux must also ensure stable burning of the welding arc and contribute to the formation of a dense weld of required shape and size, and free from pores, cracks and slag inclusions. As the deposited molten metal solidifies, the flux must form a slag crust, easily separable from the surface of the weld. This material must be of a certain chemical composition and possess definite physical properties, such as melting point, viscosity, bulk weight. The chemical composition of the flux is chosen, depending on the composition of the welded metal and electrode wire used. (Author)

Evaluation of mechanical properties of Aluminum-Copper cold sprayed and alloy 625 wire arc sprayed coatings

Science.gov (United States)

Bashirzadeh, Milad

This study examines microstructural-based mechanical properties of Al-Cu composite deposited by cold spraying and wire arc sprayed nickel-based alloy 625 coating using numerical modeling and experimental techniques. The microhardness and elastic modulus of samples were determined using the Knoop hardness technique. Hardness in both transverse and longitudinal directions on the sample cross-sections has been measured. An image-based finite element simulation algorithm was employed to determine the mechanical properties through an inverse analysis. In addition mechanical tests including, tensile, bending, and nano-indentation tests were performed on alloy 625 wire arc sprayed samples. Overall, results from the experimental tests are in relatively good agreement for deposited Al-Cu composites and alloy 625 coating. However, results obtained from numerical simulation are significantly higher in value than experimentally obtained results. Examination and comparison of the results are strong indications of the influence of microstructure characteristics on the mechanical properties of thermally spray deposited coatings.

Interelectrode plasma evolution in a hot refractory anode vacuum arc: Theory and comparison with experiment

International Nuclear Information System (INIS)

Beilis, I.I.; Goldsmith, S.; Boxman, R.L.

2002-01-01

In this paper a theoretical study of a hot refractory anode vacuum arc, which was previously investigated experimentally [Phys. Plasmas 7, 3068 (2000)], is presented. The arc was sustained between a thermally isolated refractory anode and a water-cooled copper cathode. The arc started as a multicathode-spot (MCS) vacuum arc and then switched to the hot refractory anode vacuum arc (HRAVA) mode. In the MCS mode, the cathodic plasma jet deposits a film of the cathode material on the anode. Simultaneously, the temperature of the thermally isolated anode begins to rise, reaching eventually a sufficiently high temperature to re-evaporate the deposited material, which is subsequently ionized in the interelectrode gap. The transition to the HRAVA mode is completed when the density of the interelectrode plasma consists mostly of ionized re-evaporated atoms--the anode plasma. The evolution of the HRAVA mode is characterized by the propagation of a luminous plasma plume from the anode to the cathode. The time dependent model of the various physical processes taking place during the transition to the HRAVA mode is represented by a system of equations describing atom re-evaporation, atom ionization through the interaction of the cathode jet and the interelectrode plasma with the anode vapor, plasma plume propagation, plasma radial expansion, plasma energy, and heavy particle density balance. The time dependence of the anode heat flux and the effective anode voltage were obtained by solving these equations. In addition, the time dependent plasma electron temperature, plasma density, anode potential drop, arc voltage, and anode temperature distribution were calculated and compared with previous measurements. It was shown that the observed decrease of the effective anode voltage with time during the mode transition is due to decrease of the heat flux incident on the anode surface from the cathode spot jets

Auroral arc classification scheme based on the observed arc-associated electric field pattern

International Nuclear Information System (INIS)

Marklund, G.

1983-06-01

Radar and rocket electric field observations of auroral arcs have earlier been used to identify essentially four different arc types, namely anticorrelation and correlation arcs (with, respectively, decreased and increased arc-assocaited field) and asymmetric and reversal arcs. In this paper rocket double probe and supplementary observations from the literature, obtained under various geophysical conditions, are used to organize the different arc types on a physical rather than morphological basis. This classification is based on the relative influence on the arc electric field pattern from the two current continuity mechanisms, polarisation electric fields and Birkeland currents. In this context the tangential electric field plays an essential role and it is thus important that it can be obtained with both high accuracy and resolution. In situ observations by sounding rockets are shown to be better suited for this specific task than monostatic radar observations. Depending on the dominating mechanism, estimated quantitatively for a number of arc-crossings, the different arc types have been grouped into the following main categories: Polarisation arcs, Birkeland current arcs and combination arcs. Finally the high altitude potential distributions corresponding to some of the different arc types are presented. (author)

Synthesis of Ti-doped DLC film on SS304 steels by Filtered Cathodic Vacuum Arc (FCVA) technique for tribological improvement

Science.gov (United States)

Bootkul, D.; Saenphinit, N.; Supsermpol, B.; Aramwit, C.; Intarasiri, S.

2014-08-01

Currently, stainless steels are widely used in various industrial applications due to their excellence in toughness and corrosion resistance. But their resistance to wear needs to be improved for appropriate use in tribological applications. The Filtered Cathodic Vacuum Arc (FCVA) is a superior technique for forming a high-density film structure of amorphous carbon, especially for a tetrahedral amorphous carbon (ta-C) type, because it can produce a plasma of highly energetic ions that can penetrate into a growing coating, resulting in densification of the film. However, this technique tends to generate high internal stress, due to serious accumulation of energy in the film structure that then leads to film delamination. In general, there are numerous solutions that have been used to reduce the internal stress. DLC with various additive elements such as Ti, Cr or W as strong-carbide-forming (SCF) metals is one of the popular methods to provide attractive combinations of properties of wear resistance and film adhesion as well as reducing the internal stress. The present study was focused on investigation of titanium-doped DLC coating on SS304 steel, mainly for adhesion improvement in optimizing for tribological applications. The synthesized films were formed by the FCVA technique at normal substrate temperature. In the experimental set-up, the films were produced by mixing the titanium and carbon ions generated by dual cathode plasma source operating in synchronous pulsed mode. Their compositions were adjusted by varying the relative duration of the pulse length from each cathode. Titanium doping concentration was varied from pure DLC deposition as the control group to titanium and graphite trigger pulses ratios of 1:16, 1:12, 1:10, 1:8 and 1:4, as the Ti-doped DLC group. The results showed that by increasing titanium trigger pulses ratio from 1:16, 1:12, 1:10 and 1:8, respectively, the film adhesion was increased while the wear rate did not change significantly as

Superhydrophobic hybrid membranes by grafting arc-like macromolecular bridges on graphene sheets: Synthesis, characterization and properties

Science.gov (United States)

Mo, Zhao-Hua; Luo, Zheng; Huang, Qiang; Deng, Jian-Ping; Wu, Yi-Xian

2018-05-01

Grafting single end-tethered polymer chains on the surface of graphene is a conventional way to modify the surface properties of graphene oxide. However, grafting arc-like macromolecular bridges on graphene surfaces has been barely reported. Herein, a novel arc-like polydimethylsiloxane (PDMS) macromolecular bridges grafted graphene sheets (GO-g-Arc PDMS) was successfully synthesized via a confined interface reaction at 90 °C. Both the hydrophilic α- and ω-amino groups of linear hydrophobic NH2-PDMS-NH2 macromolecular chains rapidly reacted with epoxy and carboxyl groups on the surfaces of graphene oxide in water suspension to form arc-like PDMS macromolecular bridges on graphene sheets. The grafting density of arc-like PDMS bridges on graphene sheets can reach up to 0.80 mmol g-1 or 1.32 arc-like bridges per nm2 by this confined interface reaction. The water contact angle (WCA) of the hybrid membrane could be increased with increasing both the grafting density and content of covalent arc-like bridges architecture. The superhydrophobic hybrid membrane with a WCA of 153.4° was prepared by grinding of the above arc-like PDMS bridges grafted graphene hybrid, dispersing in ethanol and filtrating by organic filter membrane. This superhydrophobic hybrid membrane shows good self-cleaning and complete oil-water separation properties, which provides potential applications in anticontamination coating and oil-water separation. To the best of our knowledge, this is the first report on the synthesis of functional hybrid membranes by grafting arc-like PDMS macromolecular bridges on graphene sheets via a confined interface reaction.

Across-arc versus along-arc Sr-Nd-Pb isotope variations in the Ecuadorian volcanic arc

Science.gov (United States)

Ancellin, Marie-Anne; Samaniego, Pablo; Vlastélic, Ivan; Nauret, François; Gannoun, Adbelmouhcine; Hidalgo, Silvana

2017-03-01

Previous studies of the Ecuadorian arc (1°N-2°S) have revealed across-arc geochemical trends that are consistent with a decrease in mantle melting and slab dehydration away from the trench. The aim of this work is to evaluate how these processes vary along the arc in response to small-scale changes in the age of the subducted plate, subduction angle, and continental crustal basement. We use an extensive database of 1437 samples containing 71 new analyses, of major and trace elements as well as Sr-Nd-Pb isotopes from Ecuadorian and South Colombian volcanic centers. Large geochemical variations are found to occur along the Ecuadorian arc, in particular along the front arc, which encompasses 99% and 71% of the total variations in 206Pb/204Pb and 87Sr/86Sr ratios of Quaternary Ecuadorian volcanics, respectively. The front arc volcanoes also show two major latitudinal trends: (1) the southward increase of 207Pb/204Pb and decrease of 143Nd/144Nd reflect more extensive crustal contamination of magma in the southern part (up to 14%); and (2) the increase of 206Pb/204Pb and decrease of Ba/Th away from ˜0.5°S result from the changing nature of metasomatism in the subarc mantle wedge with the aqueous fluid/siliceous slab melt ratio decreasing away from 0.5°S. Subduction of a younger and warmer oceanic crust in the Northern part of the arc might promote slab melting. Conversely, the subduction of a colder oceanic crust south of the Grijalva Fracture Zone and higher crustal assimilation lead to the reduction of slab contribution in southern part of the arc.

Microstructural characterisation of Inconel 718 gas tungsten arc welds

International Nuclear Information System (INIS)

Ram, G.D.J.; Reddy, A.V.; Rao, K.P.

2005-01-01

The presence of Nb-rich, brittle, intermetallic Laves phase in Inconel 718 weld fusion zones is detrimental to weld mechanical properties. In the current work, autogenous bead-on-plate gas tungsten-arc welds were deposited in 2 mm thick IN 718 sheets. The welds were subjected to the following heat treatments: i) direct aging, ii) solution treatment at 980 C followed by aging, and iii) solution treatment at 1080 C followed by aging. Detailed microstructural characterisation was carried out using optical, scanning electron and transmission electron microscopes and electron probe microanalysis. The microstructural features in as-welded and post-weld heat treated conditions are discussed. The results show that post-weld heat treatments alone cannot provide satisfactory solution to the Laves problem in Inconel 718 gas tungsten-arc welds

Thin-film X-ray filters on microstructured substrates and their thermophysical properties

Science.gov (United States)

Mitrofanov, A. V.

2018-02-01

It is shown that structured substrates having micron- or submicron-sized through holes and coated with an ultrathin organic film can be used for the fabrication of thin-film X-ray filters via direct growth of functional layers on a substrate by sputter deposition, without additional complex processing steps. An optimised process is considered for the fabrication of X-ray filters on support structures in the form of electroplated fine nickel grids and on track-etched polymer membranes with micron- and submicrondiameter through pores. 'Optimisation' is here taken to mean matching the sputter deposition conditions with the properties of substrates so as to avoid overheating. The filters in question are intended for both imaging and single-channel detectors operating in the soft X-ray and vacuum UV spectral regions, at wavelengths from 10 to 60 nm. Thermal calculations are presented for the heating of ultrathin layers of organic films and thin-film support substrates during the sputter deposition of aluminium or other functional materials. The paper discusses approaches for cooling thinfilm composites during the sputter deposition process and the service of the filters in experiments and gives a brief overview of the works that utilised filters produced by the described technique on microstructured substrates, including orbital solar X-ray research in the framework of the CORONAS programme and laboratory laser plasma experiments.

A New Method for the Deposition of Metallic Silver on Porous Ceramic Water Filters

Directory of Open Access Journals (Sweden)

Kathryn N. Jackson

2018-01-01

Full Text Available A new method of silver application to a porous ceramic water filter used for point-of-use water treatment is developed. We evaluated filter performance for filters manufactured by the conventional method of painting an aqueous suspension of silver nanoparticles onto the filter and filters manufactured with a new method that applies silver nitrate to the clay-water-sawdust mixture prior to pressing and firing the filter. Filters were evaluated using miscible displacement flow-through experiments with pulse and continuous-feed injections of E. coli. Flow characteristics were quantified by tracer experiments using [3H]H2O. Experiments using pulse injections of E. coli showed similar performance in breakthrough curves between the two application methods. Long-term challenge tests performed with a continuous feed of E. coli and growth medium resulted in similar log removal rates, but the removal rate by nanosilver filters decreased over time. Silver nitrate filters provided consistent removal with lower silver levels in the effluent and effective bacterial disinfection. Results from continued use with synthetic groundwater over 4 weeks, with a pulse injection of E. coli at 2 and 4 weeks, support similar conclusions—nanosilver filters perform better initially, but after 4 weeks of use, nanosilver filters suffer larger decreases in performance. Results show that including silver nitrate in the mixing step may effectively reduce costs, improve silver retention in the filter, increase effective lifespan, and maintain effective pathogen removal while also eliminating the risk of exposure to inhalation of silver nanoparticles by workers in developing-world filter production facilities.

Metallogenesis of Precambrian gold deposits in the Wutai greenstone belt: Constrains on the tectonic evolution of the North China Craton

Directory of Open Access Journals (Sweden)

Ju-Quan Zhang

2018-03-01

Full Text Available The Wutai greenstone belt in central North China Craton (NCC hosts a number of Precambrian gold deposits and ore occurrences. Based on the host rock association, these can be divided into Banded Iron Formation (BIF, meta-volcano-sedimentary and meta-conglomerate types. The two former types formed during ∼2.5–2.3 Ga and the third one at ∼1.85 Ga. The characteristics of these Precambrian gold deposits are broadly similar with those of the orogenic gold deposits. Based on available geochronological data, here we reconstruct the major tectonic events and their relationship with gold mineralization in the Wutai-Hengshan-Fuping region during Neoarchean to Paleoproterozoic as follows. (1 ∼2.6–2.5 Ga: widespread intrusion of tonalite-trondhjemite-granodiorite (TTG magmas in the Hengshan terrane and Fuping continental arc, formation of the Wutai volcanic arc in the southern margin of Hengshan terrane with granitoids emplacement, and the Hengshan-Wutai intra-oceanic arc accretion to the Fuping arc at the end of Neoarchean. (2 ∼2.5–2.3 Ga: the subduction of Hengshan arc from north leading to persistent magmatism and orogenic gold mineralization. (3 ∼2.2–2.1 Ga: extension leading to the formation of graben structure in the Wutai and Fuping region, deposition of the Hutuo and Wanzi Group sediments, formation of placer gold through erosion of the orogenic gold deposits. (4 ∼2.2–2.0 Ga: widespread magmatism in the Wutai-Hengshan-Fuping region. (5 ∼1.95–1.8 Ga: regional metamorphism associated with collision of the Western and Eastern Blocks of the NCC and associated orogenic gold deposits. The multiple subduction-accretion-collision history and subsequent deep erosion has significantly affected most of the Precambrian gold deposits in the Wutai greenstone belt.

Method and apparatus for a self-cleaning filter

Science.gov (United States)

Diebold, James P.; Lilley, Arthur; Browne, III, Kingsbury; Walt, Robb Ray; Duncan, Dustin; Walker, Michael; Steele, John; Fields, Michael

2010-11-16

A method and apparatus for removing fine particulate matter from a fluid stream without interrupting the overall process or flow. The flowing fluid inflates and expands the flexible filter, and particulate is deposited on the filter media while clean fluid is permitted to pass through the filter. This filter is cleaned when the fluid flow is stopped, the filter collapses, and a force is applied to distort the flexible filter media to dislodge the built-up filter cake. The dislodged filter cake falls to a location that allows undisrupted flow of the fluid after flow is restored. The shed particulate is removed to a bin for periodic collection. A plurality of filter cells can operate independently or in concert, in parallel, or in series to permit cleaning the filters without shutting off the overall fluid flow. The self-cleaning filter is low cost, has low power consumption, and exhibits low differential pressures.

Method and apparatus for a self-cleaning filter

Science.gov (United States)

Diebold, James P.; Lilley, Arthur; Browne, III, Kingsbury; Walt, Robb Ray; Duncan, Dustin; Walker, Michael; Steele, John; Fields, Michael

2013-09-10

A method and apparatus for removing fine particulate matter from a fluid stream without interrupting the overall process or flow. The flowing fluid inflates and expands the flexible filter, and particulate is deposited on the filter media while clean fluid is permitted to pass through the filter. This filter is cleaned when the fluid flow is stopped, the filter collapses, and a force is applied to distort the flexible filter media to dislodge the built-up filter cake. The dislodged filter cake falls to a location that allows undisrupted flow of the fluid after flow is restored. The shed particulate is removed to a bin for periodic collection. A plurality of filter cells can operate independently or in concert, in parallel, or in series to permit cleaning the filters without shutting off the overall fluid flow. The self-cleaning filter is low cost, has low power consumption, and exhibits low differential pressures.

Influence of arc current and pressure on non-chemical equilibrium air arc behavior

Science.gov (United States)

Yi, WU; Yufei, CUI; Jiawei, DUAN; Hao, SUN; Chunlin, WANG; Chunping, NIU

2018-01-01

The influence of arc current and pressure on the non-chemical equilibrium (non-CE) air arc behavior of a nozzle structure was investigated based on the self-consistent non-chemical equilibrium model. The arc behavior during both the arc burning and arc decay phases were discussed at different currents and different pressures. We also devised the concept of a non-equilibrium parameter for a better understanding of non-CE effects. During the arc burning phase, the increasing current leads to a decrease of the non-equilibrium parameter of the particles in the arc core, while the increasing pressure leads to an increase of the non-equilibrium parameter of the particles in the arc core. During the arc decay phase, the non-CE effect will decrease by increasing the arc burning current and the nozzle pressure. Three factors together—convection, diffusion and chemical reactions—influence non-CE behavior.

Fundamentals studies of a magnetically steered vacuum arc

Science.gov (United States)

Walke, Paul

In recent years demand from production industry for high performance cutting tools, aero and automobile engine parts has prompted research into both existing and novel methods of laying down hard, low friction coatings . A key process for the production of such coatings has been Physical Vapour Deposition (PVD) which has proved to be a consistent and reliable tool for industry. For this technique to continue to be improved and more advanced coatings to be produced, research at the fundamental level is required. This thesis describes research investigating the behaviour of the steered arc cathode spot and methods of improving existing steered arc coating technology.The majority of existing steered arc systems use either permanent magnets or a combination of permanent and electromagnets to steer the arc. Described here is a novel system which employs a pair of electromagnetic coils of cylindrical geometry which enable the arc to be positioned on a circular orbit through a range of continuously variable radii. In addition to this the coils are capable of controlling the transverse and normal magnetic field profiles independently of the steering radius selected. This enables the behaviour of the arc spot to be investigated under a range of magnetic field conditions thus allowing the comparison of measured arc behaviour with a new model of arc motion. Care has described the motion of the arc spot as a biased random walk and has derived an analytical solution to describe the time dependent, probability density function for the arc position in two dimensions. Two distributions are proposed (one in each dimension); the first describes the probability density for the arc position in the direction of driven motion, the second the probability density in the direction of arc confinement. The shape of these distributions is dependent upon the transverse and normal components of the applied magnetic field.A series of experiments are described here that measure the shape of these

Investigation of Combined High-Frequency and Arc Discharges

International Nuclear Information System (INIS)

Taran, V.S.; Nezovibatko, Yu.N.; Marinin, V.G.; Shvets, O.M.; Ridozub, V.N.; Gasilin, V.V.

2001-01-01

In this paper we analyze experiment with arc and high-frequency (HF) plasma sources carried out in modified devise of the ''Bulat'' type. The HF-sources and combined discharges have attracted considerable attention for surface cleaning and coating. The utilization of such discharges allows decreasing droplet fraction formation and providing better adhesion and microhardness values. The existence of HF-field in plasma allows obtaining either conductive or dielectric coatings and they can be deposited on any substrates. (author)

Hot-Gas Filter Ash Characterization Project

Energy Technology Data Exchange (ETDEWEB)

Swanson, M.L.; Hurley, J.P.; Dockter, B.A.; O`Keefe, C.A.

1997-07-01

Large-scale hot-gas filter testing over the past 10 years has revealed numerous cases of cake buildup on filter elements that has been difficult, if not impossible, to remove. At times, the cake can blind or bridge between candle filters, leading to filter failure. Physical factors, including particle-size distribution, particle shape, the aerodynamics of deposition, and system temperature, contribute to the difficulty in removing the cake, but chemical factors such as surface composition and gas-solid reactions also play roles in helping to bond the ash to the filters or to itself. This project is designed to perform the research necessary to determine the fuel-, sorbent-, and operations-related conditions that lead to blinding or bridging of hot-gas particle filters. The objectives of the project are threefold: (1) Determine the mechanisms by which a difficult-to-clean ash is formed and how it bridges hot-gas filters (2) Develop a method to determine the rate of bridging based on analyses of the feed coal and sorbent, filter properties, and system operating conditions and (3) Suggest and test ways to prevent filter bridging.

Structural, mechanical, electrical and wetting properties of ZrNx films deposited by Ar/N2 vacuum arc discharge: Effect of nitrogen partial pressure

Science.gov (United States)

Abdallah, B.; Naddaf, M.; A-Kharroub, M.

2013-03-01

Non-stiochiometric zirconium nitride (ZrNx) thin films have been deposited on silicon substrates by vacuum arc discharge of (N2 + Ar) gas mixtures at different N2 partial pressure ratio. The microstructure, mechanical, electrical and wetting properties of these films are studied by means of X-ray diffraction (XRD), micro-Raman spectroscopy, Rutherford back scattering (RBS) technique, conventional micro-hardness testing, electrical resistivity, atomic force microscopy (AFM) and contact angle (CA) measurements. RBS results and analysis show that the (N/Zr) ratio in the film increases with increasing the N2 partial pressure. A ZrNx film with (Zr/N) ratio in the vicinity of stoichiometric ZrN is obtained at N2 partial pressure of 10%. XRD and Raman results indicate that all deposited films have strained cubic crystal phase of ZrN, regardless of the N2 partial pressure. On increasing the N2 partial pressure, the relative intensity of (1 1 1) orientation with respect to (2 0 0) orientation is seen to decrease. The effect of N2 partial pressure on micro-hardness and the resistivity of the deposited film is revealed and correlated to the alteration of grain size, crystallographic texture, stoichiometry and residual stress developed in the film. In particular, it is found that residual stress and nitrogen incorporation in the film play crucial role in the alteration of micro-hardness and resistivity respectively. In addition, CA and AFM results demonstrate that as N2 partial pressure increases, both the surface hydrophobicity and roughness of the deposited film increase, leading to a significant decrease in the film surface free energy (SFE).

Electrostatic air filters generated by electric fields

International Nuclear Information System (INIS)

Bergman, W.; Biermann, A.H.; Hebard, H.D.; Lum, B.Y.; Kuhl, W.D.

1981-01-01

This paper presents theoretical and experimental findings on fibrous filters converted to electrostatic operation by a nonionizing electric field. Compared to a conventional fibrous filter, the electrostatic filter has a higher efficiency and a longer, useful life. The increased efficiency is attributed to a time independent attraction between polarized fibers and charged, polarized particles and a time dependent attraction between charged fibers and charged, polarized particles. The charge on the fibers results from a dynamic process of charge accumulation due to the particle deposits and a charge dissipation due to the fiber conductivity

Harmonic filter design consideration for a tire-rubber factory

Energy Technology Data Exchange (ETDEWEB)

Zebardast, A. [Azad Univ., Tehran (Iran, Islamic Republic of). Abhar Branch]|[Sharif Univ., Tehran (Iran, Islamic Republic of); Mokhtari, H. [Azad Univ., Tehran (Iran, Islamic Republic of)

2005-07-01

Nonlinear loads and arc furnace loads are the main sources of harmonic currents in power distribution systems. Harmonic currents can cause reductions in system efficiency, and shorten the lifespan of transformers and capacitor banks. This paper provided details of a filter designed to attenuate harmonic currents at a tire company in Iran. The tire company was supplied by 3 distribution transformers and an emergency transformer. Main supply was through a 132 kV/20 kV transformer, which was connected to 2 A and B stations. The AC/DC drivers generated harmonics. Harmonic measurements were performed to determine the type and size of the required filters. A summary of site harmonic measurements was provided. A passive filter was placed at a medium voltage location. A sensitivity analysis was then performed in order to assess loading effects on filter performance. The analysis was performed on all possible configurations in the plant, including load change, capacitor bank step change, and transformer energization. Resonance conditions were also examined. Results showed that attention must be paid to the filter component rating in addition to potential resonant conditions. It was concluded that resonant conditions alter when system operating conditions change. 5 refs., 7 figs.

The dual-electrode DC arc furnace-modelling brush arc conditions

OpenAIRE

Reynolds, Q.G.

2012-01-01

The dual-electrode DC arc furnace, an alternative design using an anode and cathode electrode instead of a hearth anode, was studied at small scale using computational modelling methods. Particular attention was paid to the effect of two key design variables, the arc length and the electrode separation, on the furnace behaviour. It was found that reducing the arc length to brush arc conditions was a valid means of overcoming several of the limitations of the dual-electrode design, namely high...

Analysis of local regions near the interfaces in nanostructured multicomponent cathodic – arc – vapor – deposition (CAVD) coatings (Ti-Zr-Hf-V-Nb)N

International Nuclear Information System (INIS)

Kraus-Rekhberg, R.; Pogrebnyak, A. D.; Borisyuk, V. N.; Kaverin, M. V.; Belokur, M.A.; Ponomarev, G.; Ojoshi, K.; Takeda, J.; Beresnev, V. M.; Sobol', O. V.

2013-01-01

Multicomponent, nanostructure (Ti- Zr-Hf-V-Nb)N coatings derived using cathodic – Arc – Vapor – Deposition method, were characterized by applying SPB, (μ-PIXE), EDS and SEM-analysis), XRD methods, including ''a-sin 2 φ'' procedure. It was found that through the creation of high elastic strains of compression in coating it is possible to a significant extent enhance its oxidation resistance under high-temperature annealing. During the characterization of coatings the elements and defects’ redistribution was discovered, its segregation through thermally-stimulated diffusion and the spinoidal segregation process end, in the neighborhood of the interfaces, around grains and subgrains, without substantial change of the average nanograin dimension. (authors)

Direct quantification of airborne nanoparticles composition by TXRF after collection on filters

Energy Technology Data Exchange (ETDEWEB)

Motellier, S; Lhaute, K; Guiot, A; Golanski, L; Tardif, F [CEA Grenoble, DRT, LITEN, DTNM, Laboratory of Nanochemistry and Nanosafety, 17 Avenue des Martyrs, Cedex 9, F-38054 Grenoble (France); Geoffroy, C, E-mail: sylvie.motellier@cea.fr [Elexience, 9 rue des petits ruisseaux, BP 61, 91371 Verrieres-le-Buisson Cedex (France)

2011-07-06

Direct TXRF analysis of nanoparticles deposited on filters was evaluated. Standard filters spiked with known amounts of NP were produced using an atomizer which generates an aerosol from a NP containing-liquid suspension. Polycarbonate filters provided the highest fluorescence signals and black polycarbonate filters containing chromium were further selected, Cr being used as internal standard for elemental quantification of the filter contaminants. Calibration curves were established for various NP (TiO{sub 2}, ZnO, CeO{sub 2}, Al{sub 2}O{sub 3}). Good linearity was observed. Low limits of detection were in the tens to the hundreds of ngs per filter, the method being less adapted to Al{sub 2}O{sub 3} due to the poor TXRF sensitivity for light elements. The analysis of MW-CNTs was attempted by quantification of their metal (Fe) catalyst impurities. Problems like CNT dispersion in liquids, quantification of the deposited quantity and high Fe-background contamination.

World Distribution of Uranium Deposits (UDEPO) with uranium deposit classification. 2009 ed

International Nuclear Information System (INIS)

2009-10-01

The World Distribution of Uranium Deposits (UDEPO) database provides general, technical and geological information, including references, about the worldwide uranium deposits. UDEPO has been published on the internet which allows the users to register freely and to work with datasets (http://www-nfcis.iaea.org). The UDEPO web site is designed to allow users to retrieve data sets on a variety of deposit related topics ranging from specific information on individual uranium deposits to statistical information on uranium deposits worldwide. The basic building blocks for the UDEPO database are the more than 900 individual deposits for which information is available in the database. The database is arranged in a relational database format which has one main table and a number of associated tables. Structured nature of the database allows filtering and querying the database in more systematic way. The web site provides filtering and navigation to the data from the database. It has also a statistical tool which provides summary information on number of deposits and uranium resources by type and status, and by country and status. In this respect and with regard to the data presented, the UDEPO database is a unique database which provides freely accessible information on worldwide uranium deposits. Although a great effort is spent to have complete and accurate database, the users should take into consideration that there still might be missing or outdated data for individual deposits due to the rapid changes in the uranium industry due to the new exploration works which are ongoing everyday. This document and its supplementary CD-ROM represent a snapshot of the status of the database as of the end of 2008. However, the database is being continuously updated and the latest updates and additions can be accessed from the database web site (http://wwwnfcis.iaea.org)

Gravity-Driven Deposits in an Active Margin (Ionian Sea) Over the Last 330,000 Years

Science.gov (United States)

Köng, Eléonore; Zaragosi, Sébastien; Schneider, Jean-Luc; Garlan, Thierry; Bachèlery, Patrick; Sabine, Marjolaine; San Pedro, Laurine

2017-11-01

In the Ionian Sea, the subduction of the Nubia plate underneath the Eurasia plate leads to an important sediment remobilization on the Calabrian Arc and the Mediterranean Ridge. These events are often associated with earthquakes and tsunamis. In this study, we analyze gravity-driven deposits in order to establish their recurrence time on the Calabrian Arc and the western Mediterranean Ridge. Four gravity cores collected on ridges and slope basins of accretionary prisms record turbidites, megaturbidites, slumping and micro-faults over the last 330,000 years. These turbidites were dated by correlation with a hemipelagic core with a multi-proxy approach: radiometric dating, δ18O, b* colour curve, sapropels and tephrochronology. The origin of the gravity-driven deposits was studied with a sedimentary approach: grain-size, lithology, thin section, geochemistry of volcanic glass. The results suggest three periods of presence/absence of gravity-driven deposits: a first on the western lobe of the Calabrian Arc between 330,000 and 250,000 years, a second between 120,000 years and present day on the eastern lobe of the Calabrian Arc and over the last 60,000 years on the western lobe, and a third on the Mediterranean Ridge over the last 37,000 years. Return times for gravity-driven deposits are around 1,000 years during the most important record periods. The turbidite activity also highlights the presence of volcaniclastic turbidites that seems to be link to the Etna changing morphology over the last 320,000 years.

Effects of uniformities of deposition of respirable particles on filters on determining their quartz contents by using the direct on-filter X-ray diffraction (DOF XRD) method

International Nuclear Information System (INIS)

Chen, Ching-Hwa; Tsaia, Perng-Jy; Lai, Chane-Yu; Peng, Ya-Lian; Soo, Jhy-Charm; Chen, Cheng-Yao; Shih, Tung-Sheng

2010-01-01

In this study, field samplings were conducted in three workplaces of a foundry plant, including the molding, demolding, and bead blasting, respectively. Three respirable aerosol samplers (including a 25-mm aluminum cyclone, nylon cyclone, and IOSH cyclone) were used side-by-side to collect samples from each selected workplace. For each collected sample, the uniformity of the deposition of respirable dusts on the filter was measured and its free silica content was determined by both the DOF XRD method and NIOSH 7500 XRD method (i.e., the reference method). A same trend in measured uniformities can be found in all selected workplaces: 25-mm aluminum cyclone > nylon cyclone > IOSH cyclone. Even for samples collected by the sampler with the highest uniformity (i.e., 25-mm aluminum cyclone), the use of the DOF XRD method would lead to the measured free silica concentrations 1.15-2.89 times in magnitude higher than that of the reference method. A new filter holder should be developed with the minimum uniformity comparable to that of NIOSH 7500 XRD method (=0.78) in the future. The use of conversion factors for correcting quartz concentrations obtained from the DOF XRD method based on the measured uniformities could be suitable for the foundry industry at this stage.

corrosion and wear resistant ternary Cr-C-N coatings deposited by the ARC PVD process for machining tools and machining parts

International Nuclear Information System (INIS)

Knotek, O.; Lugscheider, E.; Zimmermann, H.; Bobzin, K.

1997-01-01

With the deposition of PVD hard coatings on the tools applied in machining operations it is possible to achieve significant improvements in the performance and quality of the machining processes. Depending on the machined material and the operating principle, e.g. turning, milling or drilling, not only different machining parameters but also different coating materials are necessary. In interrupted cut machining of tempered steel, for example, the life time of Ti-C-N coated inserts is several times greater than the Ti-C-N coated ones. This is a result of the favourable thermophysical and tribological properties of Ti-N-C. The potential for tool protection by CrN coatings is a result of the high ductility and low internal stress of this coating materials. CrN films can be deposited with greater film thickness, still maintaining very good adhesion. This paper presents the development of new arc PVD coatings in the system Cr-C-N. Owing to the carbon content in the coating an increased hardness and a better wear behavior in comparison to CrN was expected. The effects of various carbon carrier gases on the coating properties were examined. The coating properties were investigated by mechanical tests. X-ray diffraction, SEM analysis and corrosion tests. Some of the coatings were tested in machining tests. The results of these tests are presented in this paper. (author)

Optical Protection Filters for Harmful Laser Beams and UV Radiation

Science.gov (United States)

Azim M., Osama A.

2007-02-01

Due to the rapid growth of radiation protection applications in various devices and instruments, it is essential to use suitable filters for eye protection of the personal working in the radiation field. Different protection filters were produced to protect from four laser beam wavelengths (at 532nm, 632.8nm, 694nm and 1064nm) and block three UV bands (UVA, UVB, and UVC). The design structure of the required dielectric multilayer filters used optical thin film technology. The computer analyses of the multilayer filter formulas were prepared using Macleod Software for the production filter processes. The deposition technique was achieved on optical substrates (Glass BK-7 and Infrasil 301) by dielectric material combinations including Dralo (mixture of oxides TiO2/Al2O3), and Lima (mixture of oxides SiO2/Al2O3); deposition by an electron beam gun. The output transmittance curves for both theoretical and experimental values of all filters are presented. To validate the suitability for use in a `real world', rather than laboratory test application, full environmental assessment was also carried out. These filters exhibited high endurance after exposing them to the durability tests (adhesion, abrasion resistance and humidity) according to military standards MIL-C-675C and MIL-C-48497A.

Optical Protection Filters for Harmful Laser Beams and UV Radiation

International Nuclear Information System (INIS)

Azim M, Osama A.

2007-01-01

Due to the rapid growth of radiation protection applications in various devices and instruments, it is essential to use suitable filters for eye protection of the personal working in the radiation field. Different protection filters were produced to protect from four laser beam wavelengths (at 532nm, 632.8nm, 694nm and 1064nm) and block three UV bands (UVA, UVB, and UVC). The design structure of the required dielectric multilayer filters used optical thin film technology. The computer analyses of the multilayer filter formulas were prepared using Macleod Software for the production filter processes. The deposition technique was achieved on optical substrates (Glass BK-7 and Infrasil 301) by dielectric material combinations including Dralo (mixture of oxides TiO2/Al2O3), and Lima (mixture of oxides SiO2/Al2O3); deposition by an electron beam gun. The output transmittance curves for both theoretical and experimental values of all filters are presented. To validate the suitability for use in a 'real world', rather than laboratory test application, full environmental assessment was also carried out. These filters exhibited high endurance after exposing them to the durability tests (adhesion, abrasion resistance and humidity) according to military standards MIL-C-675C and MIL-C-48497A

Electroless nickel plating of arc discharge synthesized carbon nanotubes for metal matrix composites

Science.gov (United States)

Jagannatham, M.; Sankaran, S.; Prathap, Haridoss

2015-01-01

Electroless nickel (EN) plating was performed on arc discharge synthesized multiwalled carbon nanotubes for various deposition times. X-ray diffraction (XRD), Transmission electron microscopy (TEM), and Raman spectroscopy characterization techniques are used to identify the presence of nickel deposition on the carbon nanotubes (CNTs) and the degree of graphitization. The results indicate that impurities are less in the purified CNTs as compared to raw carbon soot. Increasing deposition time up to 60 min increases uniform deposition of nickel throughout the length of the CNTs. However, for deposition time longer than 60 min, nickel particles are seen separated from the surface of the CNTs. Uniformly coated nickel CNTs throughout their length are potential candidates for reinforcements in composite materials. Magnetic properties of the nickel coated CNTs, with deposition time of 30 and 60 min were also evaluated. The magnetic saturation of nickel coated CNTs with deposition time of 30 min is less compared to nickel coated CNTs with deposition time of 60 min.

Effects of fixture rotation on coating uniformity for high-performance optical filter fabrication

Science.gov (United States)

Rubin, Binyamin; George, Jason; Singhal, Riju

2018-04-01

Coating uniformity is critical in fabricating high-performance optical filters by various vacuum deposition methods. Simple and planetary rotation systems with shadow masks are used to achieve the required uniformity [J. B. Oliver and D. Talbot, Appl. Optics 45, 13, 3097 (2006); O. Lyngnes, K. Kraus, A. Ode and T. Erguder, in `Method for Designing Coating Thickness Uniformity Shadow Masks for Deposition Systems with a Planetary Fixture', 2014 Technical Conference Proceedings, Optical Coatings, August 13, 2014, DOI: 10.14332/svc14.proc.1817.]. In this work, we discuss the effect of rotation pattern and speed on thickness uniformity in an ion beam sputter deposition system. Numerical modeling is used to determine statistical distribution of random thickness errors in coating layers. The relationship between thickness tolerance and production yield are simulated theoretically and demonstrated experimentally. Production yields for different optical filters produced in an ion beam deposition system with planetary rotation are presented. Single-wavelength and broadband optical monitoring systems were used for endpoint monitoring during filter deposition. Limitations of thickness tolerances that can be achieved in systems with planetary rotation are shown. Paths for improving production yield in an ion beam deposition system are described.

Plasma sprayed and electrospark deposited zirconium metal diffusion barrier coatings

International Nuclear Information System (INIS)

Hollis, Kendall J.; Pena, Maria I.

2010-01-01

Zirconium metal coatings applied by plasma spraying and electrospark deposition (ESD) have been investigated for use as diffusion barrier coatings on low enrichment uranium fuel for research nuclear reactors. The coatings have been applied to both stainless steel as a surrogate and to simulated nuclear fuel uranium-molybdenum alloy substrates. Deposition parameter development accompanied by coating characterization has been performed. The structure of the plasma sprayed coating was shown to vary with transferred arc current during deposition. The structure of ESD coatings was shown to vary with the capacitance of the deposition equipment.

Residual stress determination in thermally sprayed metallic deposits by neutron diffraction

International Nuclear Information System (INIS)

Keller, Thomas; Margadant, Nikolaus; Pirling, Thilo; Riegert-Escribano, Maria J.; Wagner, Werner

2004-01-01

Neutron diffraction was used to obtain spatially resolved strain and stress profiles in thermally sprayed metallic 'NiCrAlY' deposits (chemical composition 67 wt.% Ni, 22 wt.% Cr, 10 wt.% Al, 1 wt.% Y) and the underlying steel substrates. Samples of four different spray techniques were analyzed: atmospheric and water stabilized plasma spraying (APS and WSP), flame spraying (FS) and wire arc spraying (WAS). The results are quantitatively compared with the average in-plane residual stress determined by complementary bending tests and the hole drilling technique. While the stress profiles from the surface to the interface in the deposits are similar for all investigated spray techniques, their absolute values and gradients vary strongly. This is attributed to different quenching stresses from the impinging particles, different thermal histories the deposit/substrate systems undergo during the spraying and subsequent cooling, and also to different coating properties. In the water stabilized plasma sprayed and the wire arc sprayed deposits, a gradient in the stress-free lattice parameter was observed. Crack formation is found to be a dominant mechanism for stress relaxation in the surface plane

THE REDSHIFT DISTRIBUTION OF GIANT ARCS IN THE SLOAN GIANT ARCS SURVEY

International Nuclear Information System (INIS)

Bayliss, Matthew B.; Gladders, Michael D.; Koester, Benjamin P.; Oguri, Masamune; Hennawi, Joseph F.; Sharon, Keren; Dahle, Haakon

2011-01-01

We measure the redshift distribution of a sample of 28 giant arcs discovered as a part of the Sloan Giant Arcs Survey. Gemini/GMOS-North spectroscopy provides precise redshifts for 24 arcs, and 'redshift desert' constrains for the remaining 4 arcs. This is a direct measurement of the redshift distribution of a uniformly selected sample of bright giant arcs, which is an observable that can be used to inform efforts to predict giant arc statistics. Our primary giant arc sample has a median redshift z = 1.821 and nearly two-thirds of the arcs, 64%, are sources at z ∼> 1.4, indicating that the population of background sources that are strongly lensed into bright giant arcs resides primarily at high redshift. We also analyze the distribution of redshifts for 19 secondary strongly lensed background sources that are not visually apparent in Sloan Digital Sky Survey imaging, but were identified in deeper follow-up imaging of the lensing cluster fields. Our redshift sample for the secondary sources is not spectroscopically complete, but combining it with our primary giant arc sample suggests that a large fraction of all background galaxies that are strongly lensed by foreground clusters reside at z ∼> 1.4. Kolmogorov-Smirnov tests indicate that our well-selected, spectroscopically complete primary giant arc redshift sample can be reproduced with a model distribution that is constructed from a combination of results from studies of strong-lensing clusters in numerical simulations and observational constraints on the galaxy luminosity function.

Adjustable Grazing Incidence X-ray Optics with 0.5 Arc Second Resolution

Science.gov (United States)

Reid, Paul

We seek to develop adjustable grazing incidence optics for x-ray astronomy. The goal of this development is thin, lightweight mirrors with angular resolution of 0.5 arc seconds, comparable to the Chandra X-ray Observatory. The new mirror design consists of thin segments of a Wolter-I grazing incidence mirror, with piezo-electric material deposited directly on the back surface of the mirror. Depositing a pattern of independently addressable electrodes on top of the piezoelectric material produces an array of independent piezo cells. Energizing a particular cell introduces a localized deformation in the mirror without the need for a reaction structure. By applying the appropriate voltage to the piezo cells, it is possible to correct mirror figure errors that result from mirror fabrication, gravity release, mounting, and thermal effects. Because the thin mirrors segments are lightweight, they can be densely nested to produce collecting area thirty times that of Chandra, on an affordably priced mission. This Supporting Technology program is a follow-on to an existing APRA program. In the existing program we demonstrated the first successful deposition of piezoelectric material on thermally formed glass substrates. We showed that the localized deformations produced by the piezo cells match finite element predictions, and the piezo cell adjustment range meets requirements necessary to achieve the desired figure correction. We have also shown through simulation that representative mirror figure errors can be corrected via modeled influence functions to achieve 0.5 arc sec imaging performance. This provides a firm foundation on which to develop further the technology. We will continue to optimize the deposition of thin piezoelectric films onto thermally formed glass and electroplated metal mirror segments to improve yield and manufacturability. We will deposit piezoelectric material onto conical mirror segments and demonstrate figure correction in agreement with prediction

Formation of chemical compounds under vacuum plasma-arc deposition of nickel and its alloy onto piezoceramics

International Nuclear Information System (INIS)

Grinchenko, V.T.; Lyakhovich, T.K.; Prosina, N.I.; Khromov, S.M.

1988-01-01

The phase composition of the transition layer appearing during vacuum-arc coating of nickel and nickel alloy with copper on barium titanate and lead zirconate-titanate is identified. During vacuum plasma-arc coating of nickel and its alloy at the boundary with barium titanate and lead zirconate-titanate the Ni 2 Ti 4 O compound appears which has the crystal lattice type identical with substrate with the parity of lattice parameters. The transition layer contains nickel oxides and NiTiO 3 in the case of barium titanate. When titanate content in substrate increases the zone of reaction diffusion increases in value and becomes more complicate in composition

Plan quality comparison between 4-arc and 6-arc noncoplanar volumetric modulated arc stereotactic radiotherapy for the treatment of multiple brain metastases.

Science.gov (United States)

Yoshio, Kotaro; Mitsuhashi, Toshiharu; Wakita, Akihisa; Kitayama, Takahiro; Hisazumi, Kento; Inoue, Daisaku; Shiode, Tsuyoki; Akaki, Shiro; Kanazawa, Susumu

2018-01-04

To compare the plans of 4-arc and 6-arc noncoplanar volumetric modulated arc stereotactic radiotherapy (VMA-SRT) for multiple brain metastases and to investigate the cutoff value for the tumor number and volume for 6-arc rather than 4-arc VMA-SRT. We identified 24 consecutive multiple-target cases (3 to 19 targets in each case) with 189 total targets. We constructed plans using both 4- and 6-arc noncoplanar VMA-SRT. The prescribed dose was 36 Gy/6 fr, and it was delivered to 95% of the planning target volume (PTV). The plans were evaluated for the dose conformity using the Radiation Therapy Oncology Group and Paddick conformity indices (RCI and PCI), fall-off (Paddick gradient index [PGI]), and the normal brain dose. The median (range) RCI, PCI, and PGI was 0.94 (0.92 to 0.99), 0.89 (0.77 to 0.94), and 3.75 (2.24 to 6.54) for the 4-arc plan and 0.94 (0.91 to 0.98), 0.89 (0.76 to 0.94), and 3.65 (2.24 to 6.5) for the 6-arc plan, respectively. The median (range) of the normal brain dose was 910.3 cGy (381.4 to 1268.9) for the 4-arc plan and 898.8 cGy (377 to 1252.9) for the 6-arc plan. The PGI of the 6-arc plan was significantly superior to that of the 4-arc plan (p = 0.0076), and the optimal cutoff values for the tumor number and volume indicative of 6-arc (and not 4-arc) VMA-SRT were cases with ≥ 5 metastases and a PTV of ≥ 12.9 mL, respectively. The PCI values, however, showed no significant difference between the 2 plans. We believe these results will help in considering the use of 6-arc VMA-SRT for multiple brain metastases. Copyright © 2017 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

Assessment of the Biological Effects of Welding Fumes Emitted From Metal Active Gas and Manual Metal Arc Welding in Humans.

Science.gov (United States)

Dewald, Eva; Gube, Monika; Baumann, Ralf; Bertram, Jens; Kossack, Veronika; Lenz, Klaus; Reisgen, Uwe; Kraus, Thomas; Brand, Peter

2015-08-01

Emissions from a particular welding process, metal inert gas brazing of zinc-coated steel, induce an increase in C-reactive protein. In this study, it was investigated whether inflammatory effects could also be observed for other welding procedures. Twelve male subjects were separately exposed to (1) manual metal arc welding fumes, (2) filtered air, and (3) metal active gas welding fumes for 6 hours. Inflammatory markers were measured in serum before, and directly, 1 and 7 days after exposure. Although C-reactive protein concentrations remained unchanged, neutrophil concentrations increased directly after exposure to manual metal arc welding fumes, and endothelin-1 concentrations increased directly and 24 hours after exposure. After exposure to metal active gas and filtered air, endothelin-1 concentrations decreased. The increase in the concentrations of neutrophils and endothelin-1 may characterize a subclinical inflammatory reaction, whereas the decrease of endothelin-1 may indicate stress reduction.

Arc dynamics of a pulsed DC nitrogen rotating gliding arc discharge

Science.gov (United States)

Zhu, Fengsen; Zhang, Hao; Li, Xiaodong; Wu, Angjian; Yan, Jianhua; Ni, Mingjiang; Tu, Xin

2018-03-01

In this study, a novel pulsed direct current (DC) rotating gliding arc (RGA) plasma reactor co-driven by an external magnetic field and a tangential gas flow has been developed. The dynamic characteristics of the rotating gliding arc have been investigated by means of numerical simulation and experiment. The simulation results show that a highly turbulent vortex flow can be generated at the bottom of the RGA reactor to accelerate the arc rotation after arc ignition, whereas the magnitude of gas velocity declined significantly along the axial direction of the RGA reactor. The calculated arc rotation frequency (14.4 Hz) is reasonably close to the experimental result (18.5 Hz) at a gas flow rate of 10 l min-1. In the presence of an external magnet, the arc rotation frequency is around five times higher than that of the RGA reactor without using a magnet, which suggests that the external magnetic field plays a dominant role in the maintenance of the arc rotation in the upper zone of the RGA reactor. In addition, when the magnet is placed outside the reactor reversely to form a reverse external magnetic field, the arc can be stabilized at a fixed position in the inner wall of the outer electrode at a critical gas flow rate of 16 l min-1.

Underestimated risks of recurrent long-range ash dispersal from northern Pacific Arc volcanoes.

Science.gov (United States)

Bourne, A J; Abbott, P M; Albert, P G; Cook, E; Pearce, N J G; Ponomareva, V; Svensson, A; Davies, S M

2016-07-21

Widespread ash dispersal poses a significant natural hazard to society, particularly in relation to disruption to aviation. Assessing the extent of the threat of far-travelled ash clouds on flight paths is substantially hindered by an incomplete volcanic history and an underestimation of the potential reach of distant eruptive centres. The risk of extensive ash clouds to aviation is thus poorly quantified. New evidence is presented of explosive Late Pleistocene eruptions in the Pacific Arc, currently undocumented in the proximal geological record, which dispersed ash up to 8000 km from source. Twelve microscopic ash deposits or cryptotephra, invisible to the naked eye, discovered within Greenland ice-cores, and ranging in age between 11.1 and 83.7 ka b2k, are compositionally matched to northern Pacific Arc sources including Japan, Kamchatka, Cascades and Alaska. Only two cryptotephra deposits are correlated to known high-magnitude eruptions (Towada-H, Japan, ca 15 ka BP and Mount St Helens Set M, ca 28 ka BP). For the remaining 10 deposits, there is no evidence of age- and compositionally-equivalent eruptive events in regional volcanic stratigraphies. This highlights the inherent problem of under-reporting eruptions and the dangers of underestimating the long-term risk of widespread ash dispersal for trans-Pacific and trans-Atlantic flight routes.

Fabrication of a Cryogenic Bias Filter for Ultrasensitive Focal Plane

Science.gov (United States)

Chervenak, James; Wollack, Edward

2012-01-01

A fabrication process has been developed for cryogenic in-line filtering for the bias and readout of ultrasensitive cryogenic bolometers for millimeter and submillimeter wavelengths. The design is a microstripline filter that cuts out, or strongly attenuates, frequencies (10 50 GHz) that can be carried by wiring staged at cryogenic temperatures. The filter must have 100-percent transmission at DC and low frequencies where the bias and readout lines will carry signal. The fabrication requires the encapsulation of superconducting wiring in a dielectric-metal envelope with precise electrical characteristics. Sufficiently thick insulation layers with high-conductivity metal layers fully surrounding a patterned superconducting wire in arrayable formats have been demonstrated. A degenerately doped silicon wafer has been chosen to provide a metallic ground plane. A metallic seed layer is patterned to enable attachment to the ground plane. Thick silicon dioxide films are deposited at low temperatures to provide tunable dielectric isolation without degrading the metallic seed layer. Superconducting wiring is deposited and patterned using microstripline filtering techniques to cut out the relevant frequencies. A low Tc superconductor is used so that it will attenuate power strongly above the gap frequency. Thick dielectric is deposited on top of the circuit, and then vias are patterned through both dielectric layers. A thick conductive film is deposited conformally over the entire circuit, except for the contact pads for the signal and bias attachments to complete the encapsulating ground plane. Filters are high-aspect- ratio rectangles, allowing close packing in one direction, while enabling the chip to feed through the wall of a copper enclosure. The chip is secured in the copper wall using a soft metal seal to make good thermal and electrical contact to the outer shield.

arcControlTower: the System for Atlas Production and Analysis on ARC

International Nuclear Information System (INIS)

Filipcic, Andrej

2011-01-01

PanDA, the Atlas management and distribution system for production and analysis jobs on EGEE and OSG clusters, is based on pilot jobs to increase the throughput and stability of the job execution on grid. The ARC middleware uses a specific approach which tightly connects the job requirements with cluster capabilities like resource usage, software availability and caching of input files. The pilot concept renders the ARC features useless. The arcControlTower is the job submission system which merges the pilot benefits and ARC advantages. It takes the pilot payload from the panda server and submits the jobs to the Nordugrid ARC clusters as regular jobs, with all the job resources known in advance. All the pilot communication with the PanDA server is done by the arcControlTower, so it plays the role of a pilot factory and the pilot itself. There are several advantages to this approach: no grid middleware is needed on the worker nodes, the fair-share between the production and user jobs is tuned with the arcControlTower load parameters, the jobs can be controlled by ARC client tools. The system could be extended to other submission systems using central distribution.

Characterization of duplex stainless steel weld metals obtained by hybrid plasma-gas metal arc welding

Directory of Open Access Journals (Sweden)

Koray Yurtisik

2013-09-01

Full Text Available Despite its high efficiency, autogenous keyhole welding is not well-accepted for duplex stainless steels because it causes excessive ferrite in as-welded duplex microstructure, which leads to a degradation in toughness and corrosion properties of the material. Combining the deep penetration characteristics of plasma arc welding in keyhole mode and metal deposition capability of gas metal arc welding, hybrid plasma - gas metal arc welding process has considered for providing a proper duplex microstructure without compromising the welding efficiency. 11.1 mm-thick standard duplex stainless steel plates were joined in a single-pass using this novel technique. Same plates were also subjected to conventional gas metal arc and plasma arc welding processes, providing benchmarks for the investigation of the weldability of the material. In the first place, the hybrid welding process enabled us to achieve less heat input compared to gas metal arc welding. Consequently, the precipitation of secondary phases, which are known to be detrimental to the toughness and corrosion resistance of duplex stainless steels, was significantly suppressed in both fusion and heat affected zones. Secondly, contrary to other keyhole techniques, proper cooling time and weld metal chemistry were achieved during the process, facilitating sufficient reconstructive transformation of austenite in the ferrite phase.

Magmatic evolution of Panama Canal volcanic rocks: A record of arc processes and tectonic change.

Directory of Open Access Journals (Sweden)

David W Farris

Full Text Available Volcanic rocks along the Panama Canal present a world-class opportunity to examine the relationship between arc magmatism, tectonic forcing, wet and dry magmas, and volcanic structures. Major and trace element geochemistry of Canal volcanic rocks indicate a significant petrologic transition at 21-25 Ma. Oligocene Bas Obispo Fm. rocks have large negative Nb-Ta anomalies, low HREE, fluid mobile element enrichments, a THI of 0.88, and a H2Ocalc of >3 wt. %. In contrast, the Miocene Pedro Miguel and Late Basalt Fm. exhibit reduced Nb-Ta anomalies, flattened REE curves, depleted fluid mobile elements, a THI of 1.45, a H2Ocalc of <1 wt. %, and plot in mid-ocean ridge/back-arc basin fields. Geochemical modeling of Miocene rocks indicates 0.5-0.1 kbar crystallization depths of hot (1100-1190°C magmas in which most compositional diversity can be explained by fractional crystallization (F = 0.5. However, the most silicic lavas (Las Cascadas Fm. require an additional mechanism, and assimilation-fractional-crystallization can reproduce observed compositions at reasonable melt fractions. The Canal volcanic rocks, therefore, change from hydrous basaltic pyroclastic deposits typical of mantle-wedge-derived magmas, to hot, dry bi-modal magmatism at the Oligocene-Miocene boundary. We suggest the primary reason for the change is onset of arc perpendicular extension localized to central Panama. High-resolution mapping along the Panama Canal has revealed a sequence of inward dipping maar-diatreme pyroclastic pipes, large basaltic sills, and bedded silicic ignimbrites and tuff deposits. These volcanic bodies intrude into the sedimentary Canal Basin and are cut by normal and subsequently strike-slip faults. Such pyroclastic pipes and basaltic sills are most common in extensional arc and large igneous province environments. Overall, the change in volcanic edifice form and geochemistry are related to onset of arc perpendicular extension, and are consistent with the

Magmatic evolution of Panama Canal volcanic rocks: A record of arc processes and tectonic change

Science.gov (United States)

Cardona, Agustin; Montes, Camilo; Foster, David; Jaramillo, Carlos

2017-01-01

Volcanic rocks along the Panama Canal present a world-class opportunity to examine the relationship between arc magmatism, tectonic forcing, wet and dry magmas, and volcanic structures. Major and trace element geochemistry of Canal volcanic rocks indicate a significant petrologic transition at 21–25 Ma. Oligocene Bas Obispo Fm. rocks have large negative Nb-Ta anomalies, low HREE, fluid mobile element enrichments, a THI of 0.88, and a H2Ocalc of >3 wt. %. In contrast, the Miocene Pedro Miguel and Late Basalt Fm. exhibit reduced Nb-Ta anomalies, flattened REE curves, depleted fluid mobile elements, a THI of 1.45, a H2Ocalc of arc basin fields. Geochemical modeling of Miocene rocks indicates 0.5–0.1 kbar crystallization depths of hot (1100–1190°C) magmas in which most compositional diversity can be explained by fractional crystallization (F = 0.5). However, the most silicic lavas (Las Cascadas Fm.) require an additional mechanism, and assimilation-fractional-crystallization can reproduce observed compositions at reasonable melt fractions. The Canal volcanic rocks, therefore, change from hydrous basaltic pyroclastic deposits typical of mantle-wedge-derived magmas, to hot, dry bi-modal magmatism at the Oligocene-Miocene boundary. We suggest the primary reason for the change is onset of arc perpendicular extension localized to central Panama. High-resolution mapping along the Panama Canal has revealed a sequence of inward dipping maar-diatreme pyroclastic pipes, large basaltic sills, and bedded silicic ignimbrites and tuff deposits. These volcanic bodies intrude into the sedimentary Canal Basin and are cut by normal and subsequently strike-slip faults. Such pyroclastic pipes and basaltic sills are most common in extensional arc and large igneous province environments. Overall, the change in volcanic edifice form and geochemistry are related to onset of arc perpendicular extension, and are consistent with the idea that Panama arc crust fractured during collision

Structure and Distribution of Components in the Working Layer Upon Reconditioning of Parts by Electric-Arc Metallization

Science.gov (United States)

Skoblo, T. S.; Vlasovets, V. M.; Moroz, V. V.

2001-11-01

Reliable data on the structure of the deposited layer are very important due to the considerable instability of the process of deposition of coatings by the method of electric-arc metallization and the strict requirements for reconditioned crankshafts. The present paper is devoted to the structure of coatings obtained from powder wire based on ferrochrome-aluminum with additional alloying elements introduced into the charge.

Physically based arc-circuit interaction

International Nuclear Information System (INIS)

Zhong-Lie, L.

1984-01-01

An integral arc model is extended to study the interaction of the gas blast arc with the test circuit in this paper. The deformation in the waveshapes of arc current and voltage around the current zero has been formulated to first approximation by using a simple model of arc voltage based on the arc core energy conservation. By supplementing with the time scale for the radiation, the time rates of arc processes were amended. Both the contributions of various arc processes and the influence of circuit parameters to the arc-circuit interaction have been estimated by this theory. Analysis generated a new method of calculating test circuit parameters which improves the accurate simulation of arc-circuit interaction. The new method agrees with the published experimental results

Plasma source ion implantation of metal ions: Synchronization of cathodic-arc plasma production and target bias pulses

International Nuclear Information System (INIS)

Wood, B.P.; Reass, W.A.; Henins, I.

1995-01-01

An erbium cathodic-arc has been installed on a Plasma Source Ion Implantation (PSII) experiment to allow the implantation of erbium metal and the growth of adherent erbia (erbium oxide) films on a variety of substrates. Operation of the PSII pulser and the cathodic-arc are synchronized to achieve pure implantation, rather than the hybrid implantation/deposition being investigated in other laboratories. The relative phase of the 20 μs PSII and cathodic-arc pulses can to adjusted to tailor the energy distribution of implanted ions and suppress the initial high-current drain on the pulse modulator. The authors present experimental data on this effect and make a comparison to results from particle-in-cell simulations

Antimicrobial Air Filters Using Natural Euscaphis japonica Nanoparticles.

Directory of Open Access Journals (Sweden)

Gi Byoung Hwang

Full Text Available Controlling bioaerosols has become more important with increasing participation in indoor activities. Treatments using natural-product nanomaterials are a promising technique because of their relatively low toxicity compared to inorganic nanomaterials such as silver nanoparticles or carbon nanotubes. In this study, antimicrobial filters were fabricated from natural Euscaphis japonica nanoparticles, which were produced by nebulizing E. japonica extract. The coated filters were assessed in terms of pressure drop, antimicrobial activity, filtration efficiency, major chemical components, and cytotoxicity. Pressure drop and antimicrobial activity increased as a function of nanoparticle deposition time (590, 855, and 1150 µg/cm2(filter at 3-, 6-, and 9-min depositions, respectively. In filter tests, the antimicrobial efficacy was greater against Staphylococcus epidermidis than Micrococcus luteus; ~61, ~73, and ~82% of M. luteus cells were inactivated on filters that had been coated for 3, 6, and 9 min, respectively, while the corresponding values were ~78, ~88, and ~94% with S. epidermidis. Although statistically significant differences in filtration performance were not observed between samples as a function of deposition time, the average filtration efficacy was slightly higher for S. epidermidis aerosols (~97% than for M. luteus aerosols (~95%. High-performance liquid chromatography (HPLC and electrospray ionization-tandem mass spectrometry (ESI/MS analyses confirmed that the major chemical compounds in the E. japonica extract were 1(ß-O-galloyl pedunculagin, quercetin-3-O-glucuronide, and kaempferol-3-O-glucoside. In vitro cytotoxicity and disk diffusion tests showed that E. japonica nanoparticles were less toxic and exhibited stronger antimicrobial activity toward some bacterial strains than a reference soluble nickel compound, which is classified as a human carcinogen. This study provides valuable information for the development of a

PC-based arc ignition and arc length control system for gas tungsten arc welding

International Nuclear Information System (INIS)

Liu, Y.; Cook, G.E.; Barnett, R.J.; Springfield, J.F.

1992-01-01

In this paper, a PC-based digital control system for gas tungsten arc welding (GTAW) is presented. This system controls the arc ignition process, the arc length, and the process of welding termination. A DT2818 made by Data Translation is used for interface and A/D and D/A conversions. The digital I/O ports of the DT2818 are used for control of wirefeed, shield gas, cooling water, welding power supply, etc. The DT2818 is housed in a PC. The welding signals and status are displayed on the screen for in-process monitoring. A user can control the welding process by the keyboard

Particle loading rates for HVAC filters, heat exchangers, and ducts.

Science.gov (United States)

Waring, M S; Siegel, J A

2008-06-01

The rate at which airborne particulate matter deposits onto heating, ventilation, and air-conditioning (HVAC) components is important from both indoor air quality (IAQ) and energy perspectives. This modeling study predicts size-resolved particle mass loading rates for residential and commercial filters, heat exchangers (i.e. coils), and supply and return ducts. A parametric analysis evaluated the impact of different outdoor particle distributions, indoor emission sources, HVAC airflows, filtration efficiencies, coils, and duct system complexities. The median predicted residential and commercial loading rates were 2.97 and 130 g/m(2) month for the filter loading rates, 0.756 and 4.35 g/m(2) month for the coil loading rates, 0.0051 and 1.00 g/month for the supply duct loading rates, and 0.262 g/month for the commercial return duct loading rates. Loading rates are more dependent on outdoor particle distributions, indoor sources, HVAC operation strategy, and filtration than other considered parameters. The results presented herein, once validated, can be used to estimate filter changing and coil cleaning schedules, energy implications of filter and coil loading, and IAQ impacts associated with deposited particles. The results in this paper suggest important factors that lead to particle deposition on HVAC components in residential and commercial buildings. This knowledge informs the development and comparison of control strategies to limit particle deposition. The predicted mass loading rates allow for the assessment of pressure drop and indoor air quality consequences that result from particle mass loading onto HVAC system components.

The effect of ambient ozone and humidity on the performance of nylon and Teflon filters used in ambient air monitoring filter-pack systems

Science.gov (United States)

PE Padgett

2010-01-01

Nylon and Teflon filter media are frequently used for monitoring ambient air pollutants. These media are subject to many environmental factors that may influence adsorption and retention of particulate and gaseous nitrogenous pollutants. This study evaluated the effects of ozone and humidity on the efficacy of nylon and Teflon filters used in the US dry deposition...

Tectonic and sedimentological environments of sandstone-hosted uranium deposits, with special reference to the Karoo Basin of South Africa

International Nuclear Information System (INIS)

Le Roux, J.P.

1985-01-01

The principal tectonic and sedimentological settings for sandstone-hosted uranium deposits are described. Back-arc basins filled with post-Silurian, fluvial sediments bordering subduction zone magmatic arcs of calc-alkaline composition are considered favourable tectonic environments. The basins should be closed to prevent excessive oxidation of the sediments. Uranium deposits are concentrated near basin rims in the transition zone between uplift and basin subsidence, because of favourable sedimentary facies in those areas. Syn- and post-depositional deformation could have affected the localisation of uranium ore-bodies, while intrusive centres or uplifted arcs commonly have surrounding aprons of potential host rocks. Stratigraphic zoning is also related to source area tectonics and can be used to predict favourable sedimentary environments. Sedimentological processes had a direct influence on the permeability and carbonaceous matter content of sandstones and therefore have often controlled the localisation of ore-bodies. (author)

Sheath and arc-column voltages in high-pressure arc discharges

International Nuclear Information System (INIS)

Benilov, M S; Benilova, L G; Li Heping; Wu Guiqing

2012-01-01

Electrical characteristics of a 1 cm-long free-burning atmospheric-pressure argon arc are calculated by means of a model taking into account the existence of a near-cathode space-charge sheath and the discrepancy between the electron and heavy-particle temperatures in the arc column. The computed arc voltage exhibits a variation with the arc current I similar to the one revealed by the experiment and exceeds experimental values by no more than approximately 2 V in the current range 20-175 A. The sheath contributes about two-thirds or more of the arc voltage. The LTE model predicts a different variation of the arc voltage with I and underestimates the experimental values appreciably for low currents but by no more than approximately 2 V for I ≳ 120 A. However, the latter can hardly be considered as a proof of unimportance of the space-charge sheath at high currents: the LTE model overestimates both the resistance of the bulk of the arc column and the resistance of the part of the column that is adjacent to the cathode, and this overestimation to a certain extent compensates for the neglect of the voltage drop in the sheath. Furthermore, if the latter resistance were evaluated in the framework of the LTE model in an accurate way, then the overestimation would be still much stronger and the obtained voltage would significantly exceed those observed in the experiment.

Biocompatible Silver-containing a-C:H and a-C coatings: AComparative Study

Energy Technology Data Exchange (ETDEWEB)

Endrino, Jose Luis; Allen, Matthew; Escobar Galindo, Ramon; Zhang, Hanshen; Anders, Andre; Albella, Jose Maria

2007-04-01

Hydrogenated diamond-like-carbon (a-C:H) and hydrogen-free amorphous carbon (a-C) coatings are known to be biocompatible and have good chemical inertness. For this reason, both of these materials are strong candidates to be used as a matrix that embeds metallic elements with antimicrobial effect. In this comparative study, we have incorporated silver into diamond-like carbon (DLC) coatings by plasma based ion implantation and deposition (PBII&D) using methane (CH4) plasma and simultaneously depositing Ag from a pulsed cathodic arc source. In addition, we have grown amorphous carbon - silver composite coatings using a dual-cathode pulsed filtered cathodic-arc (FCA) source. The silver atomic content of the deposited samples was analyzed using glow discharge optical spectroscopy (GDOES). In both cases, the arc pulse frequency of the silver cathode was adjusted in order to obtain samples with approximately 5 at.% of Ag. Surface hardness of the deposited films was analyzed using the nanoindentation technique. Cell viability for both a-C:H/Ag and a-C:/Ag samples deposited on 24-well tissue culture plates has been evaluated.

Evaluation of an aSi-EPID with flattening filter free beams: Applicability to the GLAaS algorithm for portal dosimetry and first experience for pretreatment QA of RapidArc

International Nuclear Information System (INIS)

Nicolini, G.; Clivio, A.; Vanetti, E.; Cozzi, L.; Fogliata, A.; Krauss, H.; Fenoglietto, P.

2013-01-01

Purpose: To demonstrate the feasibility of portal dosimetry with an amorphous silicon mega voltage imager for flattening filter free (FFF) photon beams by means of the GLAaS methodology and to validate it for pretreatment quality assurance of volumetric modulated arc therapy (RapidArc).Methods: The GLAaS algorithm, developed for flattened beams, was applied to FFF beams of nominal energy of 6 and 10 MV generated by a Varian TrueBeam (TB). The amorphous silicon electronic portal imager [named mega voltage imager (MVI) on TB] was used to generate integrated images that were converted into matrices of absorbed dose to water. To enable GLAaS use under the increased dose-per-pulse and dose-rate conditions of the FFF beams, new operational source-detector-distance (SDD) was identified to solve detector saturation issues. Empirical corrections were defined to account for the shape of the profiles of the FFF beams to expand the original methodology of beam profile and arm backscattering correction. GLAaS for FFF beams was validated on pretreatment verification of RapidArc plans for three different TB linacs. In addition, the first pretreatment results from clinical experience on 74 arcs were reported in terms of γ analysis.Results: MVI saturates at 100 cm SDD for FFF beams but this can be avoided if images are acquired at 150 cm for all nominal dose rates of FFF beams. Rotational stability of the gantry-imager system was tested and resulted in a minimal apparent imager displacement during rotation of 0.2 ± 0.2 mm at SDD = 150 cm. The accuracy of this approach was tested with three different Varian TrueBeam linacs from different institutes. Data were stratified per energy and machine and showed no dependence with beam quality and MLC model. The results from clinical pretreatment quality assurance, provided a gamma agreement index (GAI) in the field area for six and ten FFF beams of (99.8 ± 0.3)% and (99.5 ± 0.6)% with distance to agreement and dose difference criteria

Streaming metal plasma generation by vacuum arc plasma guns

International Nuclear Information System (INIS)

MacGill, R.A.; Dickinson, M.R.; Anders, A.; Monteiro, O.R.; Brown, I.G.

1998-01-01

We have developed several different embodiments of repetitively pulsed vacuum arc metal plasma gun, including miniature versions, multicathode versions that can produce up to 18 different metal plasma species between which one can switch, and a compact high-duty cycle well-cooled version, as well as a larger dc gun. Plasma guns of this kind can be incorporated into a vacuum arc ion source for the production of high-energy metal ion beams, or used as a plasma source for thin film formation and for metal plasma immersion ion implantation and deposition. The source can also be viewed as a low-energy metal ion source with ion drift velocity in the range 20 - 200 eV depending on the metal species used. Here we describe the plasma sources that we have developed, the properties of the plasma generated, and summarize their performance and limitations. copyright 1998 American Institute of Physics

Effects of uniformities of deposition of respirable particles on filters on determining their quartz contents by using the direct on-filter X-ray diffraction (DOF XRD) method.

Science.gov (United States)

Chen, Ching-Hwa; Tsaia, Perng-Jy; Lai, Chane-Yu; Peng, Ya-Lian; Soo, Jhy-Charm; Chen, Cheng-Yao; Shih, Tung-Sheng

2010-04-15

In this study, field samplings were conducted in three workplaces of a foundry plant, including the molding, demolding, and bead blasting, respectively. Three respirable aerosol samplers (including a 25-mm aluminum cyclone, nylon cyclone, and IOSH cyclone) were used side-by-side to collect samples from each selected workplace. For each collected sample, the uniformity of the deposition of respirable dusts on the filter was measured and its free silica content was determined by both the DOF XRD method and NIOSH 7500 XRD method (i.e., the reference method). A same trend in measured uniformities can be found in all selected workplaces: 25-mm aluminum cyclone>nylon cyclone>IOSH cyclone. Even for samples collected by the sampler with the highest uniformity (i.e., 25-mm aluminum cyclone), the use of the DOF XRD method would lead to the measured free silica concentrations 1.15-2.89 times in magnitude higher than that of the reference method. A new filter holder should be developed with the minimum uniformity comparable to that of NIOSH 7500 XRD method (=0.78) in the future. The use of conversion factors for correcting quartz concentrations obtained from the DOF XRD method based on the measured uniformities could be suitable for the foundry industry at this stage. 2009 Elsevier B.V. All rights reserved.

Real-time mass measurement of dust particles deposited on vessel wall in a divertor simulator using quartz crystal microbalances

International Nuclear Information System (INIS)

Tateishi, Mizuki; Koga, Kazunori; Katayama, Ryu; Yamashita, Daisuke; Kamataki, Kunihiro; Seo, Hyunwoong; Itagaki, Naho; Shiratani, Masaharu; Ashikawa, Naoko; Masuzaki, Suguru; Nishimura, Kiyohiko; Sagara, Akio

2015-01-01

We are developing a dust monitoring method using quartz crystal microbalances (QCMs) equipped with a dust eliminating filter. Here we report a dust eliminating ratio of the filter and first measurement results of the QCMs in a divertor simulator. The volume of spherical dust in unit area on the filter and QCM under the filter were 2.09 × 10 −9 and 1.22 × 10 −10 m 3 m −2 , respectively. Thus, the dust eliminating ratio of the filter is 94.2%. The QCM without the filter gives deposition rate due to radicals and dust particles, whereas the QCM with the filter gives deposition rate predominantly due to radicals. From the results, we deduce information of mass fraction of dust particles in deposits

Microscopic characterisation of TIG-deposition and -welding

International Nuclear Information System (INIS)

Groot, P.

1992-11-01

In the framework of the European Fusion Technology Programme austenitic RVS AISI 316LN is considered as candidate material for the First Wall. In this report, among others, tungsten-arc (TIG) welding connections are investigated as a part of the ECN project 1.653. It concerns respectively; the deposition of TIG-electrode-material and the welding connection. The connections are fabricated by the Danish Welding Institute Svejsecentrals in Broendby. This study is supposed to give a welding qualification by microscopic characterisation of a TIG-deposition and a TIG-weld. 3 refs., 33 figs., 5 tabs

Stresses and Temperature Stability of Dense Wavelength Division Multiplexing Filters Prepared by Reactive Ion-Assisted E-Gun Evaporation

Science.gov (United States)

Wei, Chao-Tsang; Shieh, Han-Ping D.

2005-10-01

In this paper, we report the in situ measurement of the temperature stability of narrow-band-pass filters on different types of substrate, for dense wavelength division multiplexing (DWDM) filters in optical-fiber transmission systems. The DWDM filters were designed as all-dielectric Fabry-Perot filters and fabricated by reactive ion-assisted deposition. Ta2O5 and SiO2 were used as high- and low-refractive-index layers, respectively, for constructing the DWDM filters. The accuracy and stability of the coating process were evaluated for fabricating the DWDM filters for the temperature stability of the center wavelength. The center wavelength shift was determined to be greatly dependent on the coefficient of thermal expansion of the substrate on which the filter is deposited.

Cobalt—Styles of deposits and the search for primary deposits

Science.gov (United States)

Hitzman, Murray W.; Bookstrom, Arthur A.; Slack, John F.; Zientek, Michael L.

2017-11-30

Cobalt (Co) is a potentially critical mineral. The vast majority of cobalt is a byproduct of copper and (or) nickel production. Cobalt is increasingly used in magnets and rechargeable batteries. More than 50 percent of primary cobalt production is from the Central African Copperbelt. The Central African Copperbelt is the only sedimentary rock-hosted stratiform copper district that contains significant cobalt. Its presence may indicate significant mafic-ultramafic rocks in the local basement. The balance of primary cobalt production is from magmatic nickel-copper and nickel laterite deposits. Cobalt is present in several carbonate-hosted lead-zinc and copper districts. It is also variably present in Besshi-type volcanogenic massive sulfide and siliciclastic sedimentary rock-hosted deposits in back arc and rift environments associated with mafic-ultramafic rocks. Metasedimentary cobalt-copper-gold deposits (such as Blackbird, Idaho), iron oxide-copper-gold deposits, and the five-element vein deposits (such as Cobalt, Ontario) contain different amounts of cobalt. None of these deposit types show direct links to mafic-ultramafic rocks; the deposits may result from crustal-scale hydrothermal systems capable of leaching and transporting cobalt from great depths. Hydrothermal deposits associated with ultramafic rocks, typified by the Bou Azzer district of Morocco, represent another type of primary cobalt deposit.In the United States, exploration for cobalt deposits may focus on magmatic nickel-copper deposits in the Archean and Proterozoic rocks of the Midwest and the east coast (Pennsylvania) and younger mafic rocks in southeastern and southern Alaska; also, possibly basement rocks in southeastern Missouri. Other potential exploration targets include—The Belt-Purcell basin of British Columbia (Canada), Idaho, Montana, and Washington for different styles of sedimentary rock-hosted cobalt deposits;Besshi-type VMS deposits, such as the Greens Creek (Alaska) deposit and

Development of a double-layered ceramic filter for aerosol filtration at high-temperatures: the filter collection efficiency.

Science.gov (United States)

de Freitas, Normanda L; Gonçalves, José A S; Innocentini, Murilo D M; Coury, José R

2006-08-25

The performance of double-layered ceramic filters for aerosol filtration at high temperatures was evaluated in this work. The filtering structure was composed of two layers: a thin granular membrane deposited on a reticulate ceramic support of high porosity. The goal was to minimize the high pressure drop inherent of granular structures, without decreasing their high collection efficiency for small particles. The reticulate support was developed using the technique of ceramic replication of polyurethane foam substrates of 45 and 75 pores per inch (ppi). The filtering membrane was prepared by depositing a thin layer of granular alumina-clay paste on one face of the support. Filters had their permeability and fractional collection efficiency analyzed for filtration of an airborne suspension of phosphatic rock in temperatures ranging from ambient to 700 degrees C. Results revealed that collection efficiency decreased with gas temperature and was enhanced with filtration time. Also, the support layer influenced the collection efficiency: the 75 ppi support was more effective than the 45 ppi. Particle collection efficiency dropped considerably for particles below 2 microm in diameter. The maximum collection occurred for particle diameters of approximately 3 microm, and decreased again for diameters between 4 and 8 microm. Such trend was successfully represented by the proposed correlation, which is based on the classical mechanisms acting on particle collection. Inertial impaction seems to be the predominant collection mechanism, with particle bouncing/re-entrainment acting as detachment mechanisms.

Experimental and numerical study of pleated filters clogging

International Nuclear Information System (INIS)

Gervais, Pierre-Colin

2013-01-01

Pleated filters are widely used in air treatments because of the advantageous effective surface to overall dimension ratio they offer. Their major drawback though resides in their reduced lifetime which still needs to be controlled. Indeed, when clogging, the pressure drop considerably increases, the filtration flow is then no longer maintained which might lead to the deterioration of the media. It is then crucial to characterize the evolution of the pressure drop under operating conditions in order to best design these equipments. Part of our work consisted in studying how the operating conditions influence the geometry of the deposit. To do so, we used Single- Photon Emission Computed Tomography (SPECT), a non-destructive imaging technique that keeps intact the particle structuring. The visualization of aerosol deposit at the beginning of the filtration process allows observing preferential particle deposition on the whole height of the pleat. A numerical approach was used to study the permeability of bimodal fibrous media and we experimentally studied the local velocity as well as the biphasic flow inside pleated filter media. Comparison between experiments and simulations allowed us to validate the Geodict code for a wide range of media properties and velocities. Regarding bimodal fibrous media, the fast data acquisition has allowed testing several existing models which resulted in classifying them in a unique way. If the experimental results on the initial deposition in pleated filters are encouraging, those related to beforehand clogging point to several improvements regarding the technique we used. (author) [fr

Residual stress determination in thermally sprayed metallic deposits by neutron diffraction

Energy Technology Data Exchange (ETDEWEB)

Keller, Thomas; Margadant, Nikolaus; Pirling, Thilo; Riegert-Escribano, Maria J.; Wagner, Werner

2004-05-25

Neutron diffraction was used to obtain spatially resolved strain and stress profiles in thermally sprayed metallic 'NiCrAlY' deposits (chemical composition 67 wt.% Ni, 22 wt.% Cr, 10 wt.% Al, 1 wt.% Y) and the underlying steel substrates. Samples of four different spray techniques were analyzed: atmospheric and water stabilized plasma spraying (APS and WSP), flame spraying (FS) and wire arc spraying (WAS). The results are quantitatively compared with the average in-plane residual stress determined by complementary bending tests and the hole drilling technique. While the stress profiles from the surface to the interface in the deposits are similar for all investigated spray techniques, their absolute values and gradients vary strongly. This is attributed to different quenching stresses from the impinging particles, different thermal histories the deposit/substrate systems undergo during the spraying and subsequent cooling, and also to different coating properties. In the water stabilized plasma sprayed and the wire arc sprayed deposits, a gradient in the stress-free lattice parameter was observed. Crack formation is found to be a dominant mechanism for stress relaxation in the surface plane.

Development of amorphous silicon based EUV hardmasks through physical vapor deposition

Science.gov (United States)

De Silva, Anuja; Mignot, Yann; Meli, Luciana; DeVries, Scott; Xu, Yongan; Seshadri, Indira; Felix, Nelson M.; Zeng, Wilson; Cao, Yong; Phan, Khoi; Dai, Huixiong; Ngai, Christopher S.; Stolfi, Michael; Diehl, Daniel L.

2017-10-01

Extending extreme ultraviolet (EUV) single exposure patterning to its limits requires more than photoresist development. The hardmask film is a key contributor in the patterning stack that offers opportunities to enhance lithographic process window, increase pattern transfer efficiency, and decrease defectivity when utilizing very thin film stacks. This paper introduces the development of amorphous silicon (a-Si) deposited through physical vapor deposited (PVD) as an alternative to a silicon ARC (SiARC) or silicon-oxide-type EUV hardmasks in a typical trilayer patterning scheme. PVD offers benefits such as lower deposition temperature, and higher purity, compared to conventional chemical vapor deposition (CVD) techniques. In this work, sub-36nm pitch line-space features were resolved with a positive-tone organic chemically-amplified resist directly patterned on PVD a-Si, without an adhesion promotion layer and without pattern collapse. Pattern transfer into the underlying hardmask stack was demonstrated, allowing an evaluation of patterning metrics related to resolution, pattern transfer fidelity, and film defectivity for PVD a-Si compared to a conventional tri-layer patterning scheme. Etch selectivity and the scalability of PVD a-Si to reduce the aspect ratio of the patterning stack will also be discussed.

Antireflection coatings on plastics deposited by plasma ...

Indian Academy of Sciences (India)

Wintec

Antireflection coatings (ARCs) are deposited on the surfaces of optical elements like spectacle lenses to increase light transmission and improve their performance. In the ophthalmic .... silica layer (Zajickova et al 1998, 2001; Benitez et al. 2000; Kuhr et al 2003 .... by the contact angle of a water drop on the surface. Due to its ...

Single-Arc IMRT?

International Nuclear Information System (INIS)

Bortfeld, Thomas; Webb, Steve

2009-01-01

The idea of delivering intensity-modulated radiation therapy (IMRT) with a multileaf collimator in a continuous dynamic mode during a single rotation of the gantry has recently gained momentum both in research and industry. In this note we investigate the potential of this Single-Arc IMRT technique at a conceptual level. We consider the original theoretical example case from Brahme et al that got the field of IMRT started. Using analytical methods, we derive deliverable intensity 'landscapes' for Single-Arc as well as standard IMRT and Tomotherapy. We find that Tomotherapy provides the greatest flexibility in shaping intensity landscapes and that it allows one to deliver IMRT in a way that comes close to the ideal case in the transverse plane. Single-Arc and standard IMRT make compromises in different areas. Only in relatively simple cases that do not require substantial intensity modulation will Single-Arc be dosimetrically comparable to Tomotherapy. Compared with standard IMRT, Single-Arc could be dosimetrically superior in certain cases if one is willing to accept the spreading of low dose values over large volumes of normal tissue. In terms of treatment planning, Single-Arc poses a more challenging optimization problem than Tomotherapy or standard IMRT. We conclude that Single-Arc holds potential as an efficient IMRT technique especially for relatively simple cases. In very complex cases, Single-Arc may unduly compromise the quality of the dose distribution, if one tries to keep the treatment time below 2 min or so. As with all IMRT techniques, it is important to explore the tradeoff between plan quality and the efficiency of its delivery carefully for each individual case. (note)

A novel implementation of mARC treatment for non-dedicated planning systems using converted IMRT plans

International Nuclear Information System (INIS)

Dzierma, Yvonne; Nuesken, Frank; Licht, Norbert; Ruebe, Christian

2013-01-01

The modulated arc (mARC) technique has recently been introduced by Siemens as an analogue to VMAT treatment. However, up to now only one certified treatment planning system supports mARC planning. We therefore present a conversion algorithm capable of converting IMRT plans created by any treatment planning system into mARC plans, with the hope of expanding the availability of mARC to a larger range of clinical users and researchers. As additional advantages, our implementation offers improved functionality for planning hybrid arcs and provides an equivalent step-and-shoot plan for each mARC plan, which can be used as a back-up concept in institutions where only one linac is equipped with mARC. We present a feasibility study to outline a practical implementation of mARC plan conversion using Philips Pinnacle and Prowess Panther. We present examples for three different kinds of prostate and head-and-neck plans, for 6 MV and flattening-filter-free (FFF) 7 MV photon energies, which are dosimetrically verified. It is generally more difficult to create good quality IMRT plans in Pinnacle using a large number of beams and few segments. We present different ways of optimization as examples. By careful choosing the beam and segment arrangement and inversion objectives, we achieve plan qualities similar to our usual IMRT plans. The conversion of the plans to mARC format yields functional plans, which can be irradiated without incidences. Absolute dosimetric verification of both the step-and-shoot and mARC plans by point dose measurements showed deviations below 5% local dose, mARC plans deviated from step-and-shoot plans by no more than 1%. The agreement between GafChromic film measurements of planar dose before and after mARC conversion is excellent. The comparison of the 3D dose distribution measured by PTW Octavius 729 2D-Array with the step-and-shoot plans and with the TPS is well above the pass criteria of 90% of the points falling within 5% local dose and 3 mm distance

FEATURES OF THE REGENERATION PROCESS OF THE FILTER

Directory of Open Access Journals (Sweden)

S. Yu. Panov

2015-01-01

Full Text Available The regeneration system exercises significant influence on the efficiency and reliability of the filters. During operation of the filter it continuously increases the hydraulic resistance and the gas permeability of the filter material decreases as the deposition of the disperse phase capturable on the filter element, and to maintain the bandwidth of the filter in the filter element within the set must be periodically changed or regenerated. Thus, regeneration of a process of removing part of the dust layer with the purpose of full or partial reduction of the initial filter partitioning properties. On the basis of theoretical synthesis, physico-chemical effects of dust in layers, analysis of energy effects, developed methods of intensification of the process of regeneration of particulate filters. Pneumopulse regeneration of bag filter has been investigated, and based on it a regression equation for regeneration efficiency has been derived. It has been shown that pulse pressure exerts the dominant influence on the regeneration efficiency. The obtained model was used for assessment and prediction of the efficiency of the pneumopulse system of regeneration of bag filters at a number of structural materials producing enterprises in the Voronezh region.

Potential building sand deposits in Songkhla province area

Directory of Open Access Journals (Sweden)

Kooptarnond, K.

2002-10-01

Full Text Available An investigation of potential building sand deposits in Songkhla province area subdivided them into four regions according to their accumulation in various alluvial plains, meanders throughout alluvial deposits and residual soils. Four selected deposits, were Rattaphum-Khuan Niang, U-Taphao river, Na Mom, and Chana-Thepha regions. Information obtained from these deposits revealed a good correlation between the geomorphological features as interpreted from aerial photographs and those identified from vertical electrical resistivity sounding results. Sand samples were analysed for their physical and chemical properties. Petrographic studies were also undertaken to characterize the composition types, texture and shapes. An overview of the sand properties was used them to be within the acceptable limits for building sand. However, relatively high organic impurities and soundness were found in sand from Khuan Niang and Na Mom deposits. The result indicated a potential reconnaissance mineral resource of about 46 square kilometres.A reserve evaluation for natural building sand was carried out by using Geographic Information System (GIS. Maps of the various parameters considered were constructed in digital database format with the aid of Arc/Info and ArcView software. Overlay mapping and buffer zone modules were performed to evaluate inferred resources of building sand. The key parameters of analysis included the distance from transportation, distance from streams, lithology and thickness of sand layers. The remaining inferred sand total was of about 386 million cubic metres or about 1,021 million metric tons was therefore estimated, of which 60 percent lies in the Rattaphum-Khuan Niang region and 40 percent in the other regions.

Deposition of a conductive near-infrared cutoff filter by radio-frequency magnetron sputtering

International Nuclear Information System (INIS)

Lee, Jang-Hoon; Lee, Seung-Hyu; Yoo, Kwang-Lim; Kim, Nam-Young; Hwangbo, Chang Kwon

2002-01-01

We have designed a conductive near-infrared (NIR) cutoff filter for display application, i.e., a modified low-emissivity filter based on the three periods of the basic design of [TiO2|Ti|Ag| TiO2] upon a glass substrate and investigated the optical, structural, chemical, and electrical properties of the conductive NIR cutoff filter prepared by a radio frequency magnetron sputtering system. The results show that the average transmittance is 61.1% in the visible, that the transmittance in the NIR is less than 6.6%, and that the sheet resistance and emissivity are 0.9 Ω/□ (where □ stands for a square film) and 0.012, respectively, suggesting that the conductive NIR cutoff filter can be employed as a shield against the hazard of electromagnetic waves as well as to cut off the NIR

Miocene-Recent sediment flux in the south-central Alaskan fore-arc basin governed by flat-slab subduction

Science.gov (United States)

Finzel, Emily S.; Enkelmann, Eva

2017-04-01

The Cook Inlet in south-central Alaska contains the early Oligocene to Recent stratigraphic record of a fore-arc basin adjacent to a shallowly subducting oceanic plateau. Our new measured stratigraphic sections and detrital zircon U-Pb geochronology and Hf isotopes from Neogene strata and modern rivers illustrate the effects of flat-slab subduction on the depositional environments, provenance, and subsidence in fore-arc sedimentary systems. During the middle Miocene, fluvial systems emerged from the eastern, western, and northern margins of the basin. The axis of maximum subsidence was near the center of the basin, suggesting equal contributions from subsidence drivers on both margins. By the late Miocene, the axis of maximum subsidence had shifted westward and fluvial systems originating on the eastern margin of the basin above the flat-slab traversed the entire width of the basin. These mud-dominated systems reflect increased sediment flux from recycling of accretionary prism strata. Fluvial systems with headwaters above the flat-slab region continued to cross the basin during Pliocene time, but a change to sandstone-dominated strata with abundant volcanogenic grains signals a reactivation of the volcanic arc. The axis of maximum basin subsidence during late Miocene to Pliocene time is parallel to the strike of the subducting slab. Our data suggest that the character and strike-orientation of the down-going slab may provide a fundamental control on the nature of depositional systems, location of dominant provenance regions, and areas of maximum subsidence in fore-arc basins.

Evaluation of volumetric modulated arc therapy for cranial radiosurgery using multiple noncoplanar arcs

International Nuclear Information System (INIS)

Audet, Chantal; Poffenbarger, Brett A.; Chang, Pauling; Jackson, Paul S.; Lundahl, Robert E.; Ryu, Stephen I.; Ray, Gordon R.

2011-01-01

Purpose: To evaluate a commercial volumetric modulated arc therapy (VMAT), using multiple noncoplanar arcs, for linac-based cranial radiosurgery, as well as evaluate the combined accuracy of the VMAT dose calculations and delivery. Methods: Twelve patients with cranial lesions of variable size (0.1-29 cc) and two multiple metastases patients were planned (Eclipse RapidArc AAA algorithm, v8.6.15) using VMAT (1-6 noncoplanar arcs), dynamic conformal arc (DCA, ∼4 arcs), and IMRT (nine static fields). All plans were evaluated according to a conformity index (CI), healthy brain tissue doses and volumes, and the dose to organs at risk. A 2D dose distribution was measured (Varian Novalis Tx, HD120 MLC, 1000 MU/min, 6 MV beam) for the ∼4 arc VMAT treatment plans using calibrated film dosimetry. Results: The CI (0-1 best) average for all plans was best for ∼4 noncoplanar arc VMAT at 0.86 compared with ∼0.78 for IMRT and a single arc VMAT and 0.68 for DCA. The volumes of healthy brain receiving 50% of the prescribed target coverage dose or more (V 50% ) were lowest for the four arc VMAT [RA(4)] and DCA plans. The average ratio of the V 50% for the other plans to the RA(4) V 50% were 1.9 for a single noncoplanar arc VMAT [RA(1nc)], 1.4 for single full coplanar arc VMAT [RA(1f)] and 1.3 for IMRT. The V 50% improved significantly for single isocenter multiple metastases plan when two noncoplanar VMAT arcs were added to a full single coplanar one. The maximum dose to 5 cc of the outer 1 cm rim of healthy brain which one may want to keep below nonconsequential doses of 300-400 cGy, was 2-3 times greater for IMRT, RA(1nc) and RA(1f) plans compared with the multiple noncoplanar arc DCA and RA(4) techniques. Organs at risk near (0-4 mm) to targets were best spared by (i) single noncoplanar arcs when the targets are lateral to the organ at risk and (ii) by skewed nonvertical planes of IMRT fields when the targets are not lateral to the organ at risk. The highest dose gradient

Hybrid laser-arc welding

DEFF Research Database (Denmark)

Hybrid laser-arc welding (HLAW) is a combination of laser welding with arc welding that overcomes many of the shortfalls of both processes. This important book gives a comprehensive account of hybrid laser-arc welding technology and applications. The first part of the book reviews...... the characteristics of the process, including the properties of joints produced by hybrid laser-arc welding and ways of assessing weld quality. Part II discusses applications of the process to such metals as magnesium alloys, aluminium and steel as well as the use of hybrid laser-arc welding in such sectors as ship...... building and the automotive industry. With its distinguished editor and international team of contributors, Hybrid laser-arc welding, will be a valuable source of reference for all those using this important welding technology. Professor Flemming Ove Olsen works in the Department of Manufacturing...

Niobium-based catalysts prepared by reactive radio-frequency magnetron sputtering and arc plasma methods as non-noble metal cathode catalysts for polymer electrolyte fuel cells

International Nuclear Information System (INIS)

Ohnishi, Ryohji; Katayama, Masao; Takanabe, Kazuhiro; Kubota, Jun; Domen, Kazunari

2010-01-01

Two vacuum methods, reactive radio-frequency (RF) magnetron sputtering and arc plasma deposition, were used to prepare niobium-based catalysts for an oxygen reduction reaction (ORR) as non-noble metal cathodes for polymer electrode fuel cells (PEFCs). Thin films with various N and O contents, denoted as NbO x and Nb-O-N, were prepared on glassy carbon plates by RF magnetron sputtering with controlled partial pressures of oxygen and nitrogen. Electrochemical measurements indicated that the introduction of the nitrogen species into the thin film resulted in improved ORR activity compared to the oxide-only film. Using an arc plasma method, niobium was deposited on highly oriented pyrolytic graphite (HOPG) substrates, and the sub-nanoscale surface morphology of the deposited particles was investigated using scanning tunneling microscopy (STM). To prepare practical cathode catalysts, niobium was deposited on carbon black (CB) powders by arc plasma method. STM and transmission electron microscopy observations of samples on HOPG and CB indicated that the prepared catalysts were highly dispersed at the atomic level. The onset potential of oxygen reduction on Nb-O-N/CB was 0.86 V vs. a reversible hydrogen electrode, and the apparent current density was drastically improved by the introduction of nitrogen.

Deposition and retention of air pollutants on vegetation and other atmospheric interfaces

International Nuclear Information System (INIS)

Jonas, R.

1984-09-01

The question of the deposition of aerosols and gases are applied to biological and ecological problems concerning the filtering aspect of atmospheric interfaces, especially vegetation, with respect to air pollution, and also the resulting pollutant effect. In order to determine the deposition of aerosols, numerous field experiments were carried out. The deposition of gases was treated on the basis of current literature data. The experiments indicate that the deposition of aerosols on grass largely depends on aerosol diameter, dry weight per unit area and the wind velocity or turbulence of the air layer near the ground. Of the interfaces studied, namely soil without vegetation, water, filter paper, smooth and structured metals, grass, clover and trees, the latter had the greatest dust collecting capability. It is recommended that in the afforestation of areas in the close proximity of industrial regions the common beech, silver birch and Japanese larch should be taken into particular consideration due to their great deposition effectiveness with respect to dusts and their comparatively high resistance to pollutant gases. Silver birch and moreover red horse chestnut should be considered for filtering the air in urban regions because of the high aerosol deposition. (orig./HP) [de

Electric Arc Furnace Modeling with Artificial Neural Networks and Arc Length with Variable Voltage Gradient

Directory of Open Access Journals (Sweden)

Raul Garcia-Segura

2017-09-01

Full Text Available Electric arc furnaces (EAFs contribute to almost one third of the global steel production. Arc furnaces use a large amount of electrical energy to process scrap or reduced iron and are relevant to study because small improvements in their efficiency account for significant energy savings. Optimal controllers need to be designed and proposed to enhance both process performance and energy consumption. Due to the random and chaotic nature of the electric arcs, neural networks and other soft computing techniques have been used for modeling EAFs. This study proposes a methodology for modeling EAFs that considers the time varying arc length as a relevant input parameter to the arc furnace model. Based on actual voltages and current measurements taken from an arc furnace, it was possible to estimate an arc length suitable for modeling the arc furnace using neural networks. The obtained results show that the model reproduces not only the stable arc conditions but also the unstable arc conditions, which are difficult to identify in a real heat process. The presented model can be applied for the development and testing of control systems to improve furnace energy efficiency and productivity.

Method to reduce arc blow during DC arc welding of pipelines

Energy Technology Data Exchange (ETDEWEB)

Espina-Hernandez, J. H.; Rueda-Morales, G.L.; Caleyo, F.; Hallen, J. M. [Instituto Politecnico Nacional, Mexico, (Mexico); Lopez-Montenegro, A.; Perz-Baruch, E. [Pemex Exploracion y Produccion, Tabasco, (Mexico)

2010-07-01

Steel pipelines are huge ferromagnetic structures and can be easily subjected to arc blow during the DC arc welding process. The development of methods to avoid arc blow during pipeline DC arc welding is a major objective in the pipeline industry. This study developed a simple procedure to compensate the residual magnetic field in the groove during DC arc welding. A Gaussmeter was used to perform magnetic flux density measurements in pipelines in southern Mexico. These data were used to perform magnetic finite element simulations using FEMM. Different variables were studied such as the residual magnetic field in the groove or the position of the coil with respect to the groove. An empirical predictive equation was developed from these trials to compensate for the residual magnetic field. A new method of compensating for the residual magnetic field in the groove by selecting the number of coil turns and the position of the coil with respect to the groove was established.

Using arc voltage to locate the anode attachment in plasma arc cutting

International Nuclear Information System (INIS)

Osterhouse, D J; Heberlein, J V R; Lindsay, J W

2013-01-01

Plasma arc cutting is a widely used industrial process in which an electric arc in the form of a high velocity plasma jet is used to melt and blow away metal. The arc attaches inside the resulting cut slot, or kerf, where it both provides a large heat flux and determines the flow dynamics of the plasma. Knowledge of the position of the arc attachment is essential for understanding the phenomena present at the work piece. This work presents a new method of measuring the location of the arc attachment in which the arc voltage is measured during the cutting of a range of work piece thicknesses. The attachment location is then interpreted from the voltages. To support the validity of this method, the kerf shape, dross particle size and dross adhesion to the work piece are also observed. While these do not conclusively give an attachment location, they show patterns which are consistent with the attachment location found from the voltage measurements. The method is demonstrated on the cutting of mild steel, where the arc attachment is found to be stationary in the upper portion of the cut slot and in reasonable agreement with existing published findings. For a process optimized for the cutting of 12.7 mm mild steel, the attachment is found at a depth of 1.5–3.4 mm. For a slower process optimized for the cutting of 25.4 mm mild steel, the attachment is found at a depth of 3.4–4.8 mm, which enhances heat transfer further down in the kerf, allowing cutting of the thicker work piece. The use of arc voltage to locate the position of the arc attachment is unique when compared with existing methods because it is entirely independent of the heat distribution and visualization techniques. (paper)

Cathode deposits in fullerene formation — microstructural evidence for independent pathways of pyrolytic carbon and nanobody formation

Science.gov (United States)

Taylor, G. H.; Gerald, J. D. Fitz; Pang, L.; Wilson, M. A.

1994-01-01

Microstructures in cathode deposits formed during fullerene production by electrical arcing in helium have been examined in detail. This has provided new information about the mechanisms by which nanobodies (nanotubes and nanoparticles) and pyrolytic carbon are deposited. Nanobodies and pyrolytic carbon form independently; the former probably grow in the plasma then deposit on the electrode but much of the latter deposits directly on the electrode surface.

Loss of collected particles from the filter of the stack monitor, the Ringhals-1 power reactor

International Nuclear Information System (INIS)

Stroem, L.

1993-01-01

The function of the filter holder was examined in the laboratory and in the Ringhals measurement installation. It was concluded that a loss of sample could occur, if the filter has a heavy particle deposit. An approximate relation between deposits thickness and loss of sample could be determined. Particle concentration in the stack air is sometimes so high, that loss of sample can occur. The test have also revealed that the sample air stream can by-pass the filter, without proper indication of the defect. Control instrumentation is proposed

Crustal growth of the Izu-Ogasawara arc estimated from structural characteristics of Oligocene arc

Science.gov (United States)

Takahashi, N.; Yamashita, M.; Kodaira, S.; Miura, S.; Sato, T.; No, T.; Tatsumi, Y.

2011-12-01

Japan Agency for Marine-Earth Science and Technology (JAMSTEC) carried out seismic surveys using a multichannel reflection system and ocean bottom seismographs, and we have clarified crustal structures of whole Izu-Ogasawara (Bonin)-Marina (IBM) arc since 2002. These refection images and velocity structures suggest that the crustal evolution in the intra-oceanic island arc accompanies with much interaction of materials between crust and mantle. Slow mantle velocity identified beneath the thick arc crusts suggests that dense crustal materials transformed into the mantle. On the other hand, high velocity lower crust can be seen around the bottom of the crust beneath the rifted region, and it suggests that underplating of mafic materials occurs there. Average crustal production rate of the entire arc is larger than expected one and approximately 200 km3/km/Ma. The production rate of basaltic magmas corresponds to that of oceanic ridge. Repeated crustal differentiation is indispensable to produce much light materials like continental materials, however, the real process cannot still be resolved yet. We, therefore, submitted drilling proposals to obtain in-situ middle crust with P-wave velocity of 6 km/s. In the growth history of the IBM arc, it is known by many papers that boninitic volcanisms preceded current bimodal volcanisms based on basaltic magmas. The current volcanisms accompanied with basaltic magmas have been occurred since Oligocene age, however, the tectonic differences to develop crustal architecture between Oligocene and present are not understood yet. We obtained new refraction/reflection data along an arc strike of N-S in fore-arc region. Then, we estimate crustal structure with severe change of the crustal thickness from refraction data, which are similar to that along the volcanic front. Interval for location of the thick arc crust along N-S is very similar to that along the volcanic front. The refection image indicates that the basement of the fore-arc

Influence of Post-treatment Methods on Pressure Change of Filter Bag

Directory of Open Access Journals (Sweden)

Yihua Yin

2016-01-01

Full Text Available The PPS needle-punched non-woven filters with different post-treatments were studied by filter testing system. The pressure drop was measured at various filtration velocity, dust deposition time and the temperature during the experiment; and the effect of dust-cleaning as the consequence of pressure of filter bag was measured. The results showed that post-treatments transformed the surfaces of filters, and the dust formation differed greatly. Excessively high filtration velocity decreased the peak pressure in the process of dust-cleaning. The pressure of filter bag was increased as the dust layers were thickened. The higher temperature in filtration rose the peak pressure of filter bag, but decreased the rate of rising.

Diffuse and spot mode of cathode arc attachments in an atmospheric magnetically rotating argon arc

International Nuclear Information System (INIS)

Chen, Tang; Wang, Cheng; Liao, Meng-Ran; Xia, Wei-Dong

2016-01-01

A model including the cathode, near-cathode region, and arc column was constructed. Specifically, a thermal perturbation layer at the arc fringe was calculated in order to couple sheath/presheath modelling with typical arc column modelling. Comparative investigation of two modes of attachment of a dc (100, 150, 200 A) atmospheric-pressure arc in argon to a thermionic cathode made of pure tungsten was conducted. Computational data revealed that there exists two modes of arc discharge: the spot mode, which has an obvious cathode surface temperature peak in the arc attachment centre; and the diffuse mode, which has a flat cathode surface temperature distribution and a larger arc attachment area. The modelling results of the arc attachment agree with previous experimental observations for the diffuse mode. A further 3D simulation is obviously needed to investigate the non-axisymmetrical features, especially for the spot mode. (paper)

On a multiscale approach for filter efficiency simulations

KAUST Repository

Iliev, Oleg; Lakdawala, Zahra; Printsypar, Galina

2014-01-01

geometry) of the filtering medium and on the diameter distribution of the particles. The deposited (captured) particles change the microstructure of the porous media what leads to change of permeability. The changed permeability directly influences

Interactions between laser and arc plasma during laser-arc hybrid welding of magnesium alloy

Science.gov (United States)

Liu, Liming; Chen, Minghua

2011-09-01

This paper presents the results of the investigation on the interactions between laser and arc plasma during laser-arc hybrid welding on magnesium alloy AZ31B using the spectral diagnose technique. By comparably analyzing the variation in plasma information (the shape, the electron temperature and density) of single tungsten inert gas (TIG) welding with the laser-arc hybrid welding, it is found that the laser affects the arc plasma through the keyhole forming on the workpiece. Depending on the welding parameters there are three kinds of interactions taking place between laser and arc plasma.

Quantitative Assessment of Spray Deposition with Water-Sensitive Paper

Science.gov (United States)

Spray droplets, discharged from the lower six nozzles of an airblast sprayer, were sampled on pairs of absorbent filter and water-sensitive papers at nine distances from sprayer. Spray deposition on filter targets were measured by fluorometry and spray distribution on WSP targets were assessed by t...

Arc-to-arc mini-sling 1999: a critical analysis of concept and technology

Directory of Open Access Journals (Sweden)

Paulo Palma

2011-04-01

Full Text Available PURPOSE: The aim of this study was to critically review the Arc-to-Arc mini-sling (Palma's technique a less invasive mid-urethral sling using bovine pericardium as the sling material. MATERIALS AND METHODS: The Arc-to-Arc mini-sling, using bovine pericardium, was the first published report of a mini-sling, in 1999. The technique was identical to the "tension-free tape" operation, midline incision and dissection of the urethra. The ATFP (white line was identified by blunt dissection, and the mini-sling was sutured to the tendinous arc on both sides with 2 polypropylene 00 sutures. RESULTS: The initial results were encouraging, with 9/10 patients cured at the 6 weeks post-operative visit. However, infection and extrusion of the mini-sling resulted in sling extrusion and removal, with 5 patients remaining cured at 12 months. CONCLUSION: The Arc-to-Arc mini-sling was a good concept, but failed because of the poor technology available at that time. Further research using new materials and better technology has led to new and safer alternatives for the management of stress urinary incontinence.

Carbon nanotube filters

Science.gov (United States)

Srivastava, A.; Srivastava, O. N.; Talapatra, S.; Vajtai, R.; Ajayan, P. M.

2004-09-01

Over the past decade of nanotube research, a variety of organized nanotube architectures have been fabricated using chemical vapour deposition. The idea of using nanotube structures in separation technology has been proposed, but building macroscopic structures that have controlled geometric shapes, density and dimensions for specific applications still remains a challenge. Here we report the fabrication of freestanding monolithic uniform macroscopic hollow cylinders having radially aligned carbon nanotube walls, with diameters and lengths up to several centimetres. These cylindrical membranes are used as filters to demonstrate their utility in two important settings: the elimination of multiple components of heavy hydrocarbons from petroleum-a crucial step in post-distillation of crude oil-with a single-step filtering process, and the filtration of bacterial contaminants such as Escherichia coli or the nanometre-sized poliovirus (~25 nm) from water. These macro filters can be cleaned for repeated filtration through ultrasonication and autoclaving. The exceptional thermal and mechanical stability of nanotubes, and the high surface area, ease and cost-effective fabrication of the nanotube membranes may allow them to compete with ceramic- and polymer-based separation membranes used commercially.

A kuroko-type polymetallic sulfide deposit in a submarine silicic caldera

Science.gov (United States)

Iizasa; Fiske; Ishizuka; Yuasa; Hashimoto; Ishibashi; Naka; Horii; Fujiwara; Imai; Koyama

1999-02-12

Manned submersible studies have delineated a large and actively growing Kuroko-type volcanogenic massive sulfide deposit 400 kilometers south of Tokyo in Myojin Knoll submarine caldera. The sulfide body is located on the caldera floor at a depth of 1210 to 1360 meters, has an area of 400 by 400 by 30 meters, and is notably rich in gold and silver. The discovery of a large Kuroko-type polymetallic sulfide deposit in this arc-front caldera raises the possibility that the numerous unexplored submarine silicic calderas elsewhere might have similar deposits.

New Raman-peak at 1850 cm(-1) observed in multiwalled carbon nanotubes produced by hydrogen arc discharge.

Science.gov (United States)

Chen, B; Kadowaki, Y; Inoue, S; Ohkohchi, M; Zhao, X; Ando, Y

2010-06-01

The new peak (near 1850 cm(-1)) assigned to carbon linear chain included in the centre of very thin innermost multiwalled carbon nanotubes (MWNTs) has been verified by Raman spectroscopy. These MWNTs were produced by dc arc discharge of pure graphite rods in pure hydrogen gas and existed in the cathode deposit. In this paper, we clarified that the new Raman-peaks could also be observed in the cathode deposit including MWNTs produced by hydrogen dc arc discharge using graphite electrode with added Y or La. By changing the quantity of addition (Y or La), dc arc current and pressure of ambient hydrogen gas, the optimum condition to get maximum intensity of the new Raman-peaks was obtained. For the case of 1 wt% La, dc 50 A, H2 pressure of 50 Torr was found to be optimum, and the intensity of new Raman-peak was even higher than the G-band peak. For the case of 1 wt% Y, dc 50 A, H2 pressure of 50 Torr was optimum, but the intensity of new Raman-peak was weaker than the G-band peak. Transmission electron microscopy observation revealed that the crystallinity of MWNTs produced with pure graphite rod was better than those produced with added Y or La.

Shunting arc plasma source for pure carbon ion beam

Energy Technology Data Exchange (ETDEWEB)

Koguchi, H.; Sakakita, H.; Kiyama, S.; Shimada, T.; Sato, Y.; Hirano, Y. [Energy Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan)

2012-02-15

A plasma source is developed using a coaxial shunting arc plasma gun to extract a pure carbon ion beam. The pure carbon ion beam is a new type of deposition system for diamond and other carbon materials. Our plasma device generates pure carbon plasma from solid-state carbon material without using a hydrocarbon gas such as methane gas, and the plasma does not contain any hydrogen. The ion saturation current of the discharge measured by a double probe is about 0.2 mA/mm{sup 2} at the peak of the pulse.

Shunting arc plasma source for pure carbon ion beam.

Science.gov (United States)

Koguchi, H; Sakakita, H; Kiyama, S; Shimada, T; Sato, Y; Hirano, Y

2012-02-01

A plasma source is developed using a coaxial shunting arc plasma gun to extract a pure carbon ion beam. The pure carbon ion beam is a new type of deposition system for diamond and other carbon materials. Our plasma device generates pure carbon plasma from solid-state carbon material without using a hydrocarbon gas such as methane gas, and the plasma does not contain any hydrogen. The ion saturation current of the discharge measured by a double probe is about 0.2 mA∕mm(2) at the peak of the pulse.

Genesis of Pb-Zn-Cu-Ag Deposits within Permian Carboniferous-Carbonate Rocks in Madina Regency, North Sumatra

Directory of Open Access Journals (Sweden)

Bhakti Hamonangan Harahap

2015-09-01

Full Text Available DOI:10.17014/ijog.2.3.167-184Strong mineralized carbonate rock-bearing Pb-Zn-Cu-Ag-(Au ores are well exposed on the Latong River area, Madina Regency, North Sumatra Province. The ore deposit is hosted within the carbonate rocks of the Permian to Carboniferous Tapanuli Group. It is mainly accumulated in hollows replacing limestone in the forms of lensoidal, colloform, veins, veinlets, cavity filling, breccia, and dissemination. The ores dominantly consist of galena (126 000 ppm Pb and sphalerite (2347 ppm Zn. The other minerals are silver, azurite, covellite, pyrite, marcasite, and chalcopyrite. This deposit was formed by at least three phases of mineralization, i.e. pyrite and then galena replaced pyrite, sphalerite replaced galena, and pyrite. The last phase is the deposition of chalcopyrite that replaced sphalerite. The Latong sulfide ore deposits posses Pb isotope ratio of 206Pb/204Pb = 19.16 - 20.72, 207Pb/204Pb = 16.16 - 17.29, and 208Pb/204Pb = 42.92 - 40.78. The characteristic feature of the deposit indicates that it is formed by a sedimentary process rather than an igneous activity in origin. This leads to an interpretation that the Latong deposit belongs to the Sedimentary Hosted Massive Sulfide (SHMS of Mississippi Valley-Type (MVT. The presence of SHMS in the island arc such as Sumatra has become controversial. For a long time, ore deposits in the Indonesian Island Arc are always identical with the porphyry and hydrothermal processes related to arc magmatism. This paper is dealing with the geology of Latong and its base metal deposits. This work is also to interpret their genesis as well as general relationship to the regional geology and tectonic setting of Sumatra.

[Filtering facepieces: effect of oily aerosol load on penetration through the filtering material].

Science.gov (United States)

Plebani, Carmela; Listrani, S; Di Luigi, M

2010-01-01

Electrostatic filters are widely used in applications requiring high filtration efficiency and low pressure drop. However various studies showed that the penetration through electrostatic filters increases during exposure to an aerosol flow. This study investigates the effects of prolonged exposure to an oily aerosol on the penetration through filtering facepieces available on the market. Some samples of FFP1, FFP2 and FFP3 filtering facepieces were exposed for 8 hours consecutively to a paraffin oil polydisperse aerosol. At the end of the exposure about 830 mg of paraffin oil were deposited in the facepiece. All the examined facepieces showed penetration values that increased with paraffin oil load while pressure drop values were substantially the same before and after exposure. The measured maximum penetration values did not exceed the maximum penetration values allowed by the European technical standards, except in one case. According to the literature, 830 mg of oil load in a facepiece is not feasible in workplaces over an eight- hour shift. However, the trend of the penetration versus exposure mass suggests that if the load increases, the penetration may exceed the maximum allowed values. For comparison a mechanical filter was also studied. This showed an initial pressure drop higher than FFP2 filtering facepieces characterized by comparable penetration values. During exposure the pressure drop virtually doubled while penetration did not change. The increase in penetration with no increase in pressure drop in the analyzed facepieces indicates that it is necessary to comply with the information supplied by the manufacturer that restricts their use to a single shift.

Studies of steered arc motion and macroparticle production in PVD processing

International Nuclear Information System (INIS)

Craven, A.L.

2000-03-01

During the past decade the production industry has constantly strived to improve performance and cut costs, this has been aided by the development of high performance tools. The advancement of these tools has been accomplished by the application of hard wearing, low friction, coatings. A key process in the production of such coatings is Physical Vapour Deposition (PVD). Interest in such thin films has led to much research effort, both academic and industrial, being devoted to the area. In order that these advancements in technology continue, research into the fundamental aspects of PVD is required. This thesis describes research and experimental studies which have been performed to study the effect of 'steering' an electric arc on various aspects of its behaviour. 'Steering' of the arc is achieved by applying external magnetic fields which allow the guidance of the path of the arc. Work by earlier authors has aimed to control the arc more fully. The research presented here is based of a novel electromagnetic three coil steering array of cylindrical geometry. With such coils it is possible to vary the field profiles to a greater degree than has been previously achieved, permitting a greater range of steering arrangements/fields to be applied. The research presented is divided into two distinct areas: Firstly a number of experiments were performed to assess the effectiveness of the new steering coils on the motion of the arc. A personal computer was used here along with new arc motion monitoring electronics. This enabled the simultaneous measurement of the orbital transit times and also the degree of travel perpendicular to the steered direction of motion of the arc, as it traversed the surface of the cathode. Such information was then used to produce values for standard deviation of the arc from its steered path, velocity of the arc and a diffusion constant related to the motion of the are. Such values then allowed evaluation of the stochastic model of arc motion

Development of an intense negative hydrogen ion source with a wide-range of external magnetic filter field

International Nuclear Information System (INIS)

Takeiri, Y.; Ando, A.; Kaneko, O.

1994-09-01

An intense negative hydrogen ion source has been developed, which has a strong external magnetic filter field in the wide area of 35 cm x 62 cm produced by a pair of permanent magnet rows located with 35.4 cm separation. The filter strength is 70 G in the center and the line-integrated filter strength is 850 G cm, which keeps the low electron temperature in the extraction region. Strong cusp magnetic field, 1.8 kG on the chamber surface, is generated for improvement of the plasma confinement. These resulted in the high arc efficiency at the low operational gas pressure. A 16.2 A of the H - ion current with the energy of 47 keV was obtained at the arc efficiency of 0.1 A/kW at the gas pressure of 3.8 mTorr in the cesium-mode operation. The magnetic field in the extraction gap is also strong, 450 G, for the electron suppression. The ratio of the extraction to the negative ion currents was less than 2.2 at the gas pressure of 3 mTorr. The two-stage acceleration was tried, and a 13.6 A of the H - ion beam was accelerated to 125 keV. (author)

Unzipping of the volcano arc, Japan

Science.gov (United States)

Stern, R.J.; Smoot, N.C.; Rubin, M.

1984-01-01

A working hypothesis for the recent evolution of the southern Volcano Arc, Japan, is presented which calls upon a northward-progressing sundering of the arc in response to a northward-propagating back-arc basin extensional regime. This model appears to explain several localized and recent changes in the tectonic and magrnatic evolution of the Volcano Arc. Most important among these changes is the unusual composition of Iwo Jima volcanic rocks. This contrasts with normal arc tholeiites typical of the rest of the Izu-Volcano-Mariana and other primitive arcs in having alkaline tendencies, high concentrations of light REE and other incompatible elements, and relatively high silica contents. In spite of such fractionated characteristics, these lavas appear to be very early manifestations of a new volcanic and tectonic cycle in the southern Volcano Arc. These alkaline characteristics and indications of strong regional uplift are consistent with the recent development of an early stage of inter-arc basin rifting in the southern Volcano Arc. New bathymetric data are presented in support of this model which indicate: 1. (1) structural elements of the Mariana Trough extend north to the southern Volcano Arc. 2. (2) both the Mariana Trough and frontal arc shoal rapidly northwards as the Volcano Arc is approached. 3. (3) rugged bathymetry associated with the rifted Mariana Trough is replaced just south of Iwo Jima by the development of a huge dome (50-75 km diameter) centered around Iwo Jima. Such uplifted domes are the immediate precursors of rifts in other environments, and it appears that a similar situation may now exist in the southern Volcano Arc. The present distribution of unrifted Volcano Arc to the north and rifted Mariana Arc to the south is interpreted not as a stable tectonic configuration but as representing a tectonic "snapshot" of an arc in the process of being rifted to form a back-arc basin. ?? 1984.

Tokamak ARC damage

International Nuclear Information System (INIS)

Murray, J.G.; Gorker, G.E.

1985-01-01

Tokamak fusion reactors will have large plasma currents of approximately 10 MA with hundreds of megajoules stored in the magnetic fields. When a major plasma instability occurs, the disruption of the plasma current induces voltage in the adjacent conducting structures, giving rise to large transient currents. The induced voltages may be sufficiently high to cause arcing across sector gaps or from one protruding component to another. This report reviews a tokamak arcing scenario and provides guidelines for designing tokamaks to minimize the possibility of arc damage

Tokamak ARC damage

Energy Technology Data Exchange (ETDEWEB)

Murray, J.G.; Gorker, G.E.

1985-01-01

Tokamak fusion reactors will have large plasma currents of approximately 10 MA with hundreds of megajoules stored in the magnetic fields. When a major plasma instability occurs, the disruption of the plasma current induces voltage in the adjacent conducting structures, giving rise to large transient currents. The induced voltages may be sufficiently high to cause arcing across sector gaps or from one protruding component to another. This report reviews a tokamak arcing scenario and provides guidelines for designing tokamaks to minimize the possibility of arc damage.

1000-kVA arc power supply

International Nuclear Information System (INIS)

Wright, R.E.; Barber, G.C.; Ponte, N.S.

1979-01-01

Because of ever-increasing power demands for the development of the Oak Ridge duoPIGatron ion source, a continuous-duty arc power supply was constructed for the Medium Energy Test Facility (METF) to furnish power for the plasma generator of experimental ion sources. The power supply utilizes 12-pulse rectification with half-wave switching in a delta and wye full-wave bridge that may be connected in series or parallel. It will deliver 340 V dc, 2500 A to an ion source when series connected and 170 V dc, 5000 A when paralleled connected. Silicon-controlled rectifiers (SCR) in each rectifier bridge can be switched for pulses as short as 10 ms through continuous duty. The filter section that reduces the ripple in the output consists of an inductor-to-capacitor (L-C) filter to smooth the 720-Hz pulses. The power transformer serves as an isolation transformer allowing the secondary to be elevated to the accelerating potential of the ion source. The dc output level is controlled with a 1000-kVA auto transformer connected to the primary of the power transformer. All elevated voltages and currents are monitored at ground potential with an optical telemetry system. This paper describes the power supply in detail, including block diagrams, component specifications, and waveforms when supplying power to an ion source

High-speed cinematography of gas-tungsten arc welding: theory and application

Energy Technology Data Exchange (ETDEWEB)

Reynolds, L.D.; Key, J.F.

1981-06-01

High-speed photo-instrumentation theory and application are reviewed, with particular emphasis on high-speed cinematography, for the engineer who has not acquired an extensive background in scientific photography. Camera systems, optics, timing system, lighting, photometric equipment, filters, and camera mounts are covered. Manufacturers and other resource material are listed in the Appendices. The properties and processing of photosensitive materials suitable for high-speed photography are reviewed, and selected film data are presented. Methods are described for both qualitative and quantitative film analysis. This technology is applied to the problem of analyzing plasma dynamics in a gas-tungsten welding arc.

Characteristics of CrAlSiN + DLC coating deposited by lateral rotating cathode arc PVD and PACVD process

Energy Technology Data Exchange (ETDEWEB)

Lukaszkowicz, Krzysztof, E-mail: krzysztof.lukaszkowicz@polsl.pl [Institute of Engineering Materials and Biomaterials, Silesian University of Technology, Konarskiego St. 18A, 44-100 Gliwice (Poland); Sondor, Jozef, E-mail: j.sondor@liss.cz [LISS, a.s., Dopravni 2603, 756 61 Roznov p.R. (Czech Republic); Balin, Katarzyna, E-mail: katarzyna.balin@us.edu.pl [A. Chełkowski Institute of Physic, University of Silesia, Uniwersytecka 4, 40-007 Katowice (Poland); Kubacki, Jerzy, E-mail: jerzy.kubacki@us.edu.pl [A. Chełkowski Institute of Physic, University of Silesia, Uniwersytecka 4, 40-007 Katowice (Poland)

2014-09-01

Highlights: • The chemical composition of the CrAlSiN + DLC coatings was studied. • The coatings have nanostructural character with fine crystallites. • Their average size grain is less than 10 nm. • The coatings demonstrate friction coefficient within the range 0.05–0.07. • The coating demonstrated a dense cross-sectional morphology as well as good adhesion to the substrate. - Abstract: Coating system composed of CrAlSiN film covered by diamond-like carbon (DLC)-based lubricant, deposited on hot work tool steel substrate was the subject of the research. The CrAlSiN and DLC layers were deposited by PVD lateral rotating ARC-cathodes (LARC) and PACVD technology on the X40CrMoV5-1 respectively. HRTEM investigation shows an amorphous character of DLC layer. It was found that the tested CrAlSiN layer has a nanostructural character with fine crystallites while their average size is less than 10 nm. Based on the XRD pattern of the CrAlSiN, the occurrence of fcc phase was only observed in the coating, the texture direction 〈3 1 1〉 is perpendicular to the sample surface. Combined SEM, AES and ToF-SIMS studies confirmed assumed chemical composition and layered structure of the coating. The chemical distribution of the elements inside the layers and at the interfaces was analyzed by SEM and AES methods. It was shown that additional CrN layer is present between substrate and CrAlSiN coating. The atomic concentration of the particular elements of DLC and CrAlSiN layer was calculated from the XPS measurements. In sliding dry friction conditions the friction coefficient for the investigated elements is set in the range between 0.05 and 0.07. The investigated coating reveals high wear resistance. The coating demonstrated a dense cross-sectional morphology as well as good adhesion to the substrate.

Geology and metallogeny of the Ar Rayn terrane, eastern Arabian shield: Evolution of a Neoproterozoic continental-margin arc during assembly of Gondwana within the East African orogen

Science.gov (United States)

Doebrich, J.L.; Al-Jehani, A. M.; Siddiqui, A.A.; Hayes, T.S.; Wooden, J.L.; Johnson, P.R.

2007-01-01

The Neoproterozoic Ar Rayn terrane is exposed along the eastern margin of the Arabian shield. The terrane is bounded on the west by the Ad Dawadimi terrane across the Al Amar fault zone (AAF), and is nonconformably overlain on the east by Phanerozoic sedimentary rocks. The terrane is composed of a magmatic arc complex and syn- to post-orogenic intrusions. The layered rocks of the arc, the Al Amar group (>689 Ma to ???625 Ma), consist of tholeiitic to calc-alkaline basaltic to rhyolitic volcanic and volcaniclastic rocks with subordinate tuffaceous sedimentary rocks and carbonates, and are divided into an eastern and western sequence. Plutonic rocks of the terrane form three distinct lithogeochemical groups: (1) low-Al trondhjemite-tonalite-granodiorite (TTG) of arc affinity (632-616 Ma) in the western part of the terrane, (2) high-Al TTG/adakite of arc affinity (689-617 Ma) in the central and eastern part of the terrane, and (3) syn- to post-orogenic alkali granite (607-583 Ma). West-dipping subduction along a trench east of the terrane is inferred from high-Al TTG/adakite emplaced east of low-Al TTG. The Ar Rayn terrane contains significant resources in epithermal Au-Ag-Zn-Cu-barite, enigmatic stratiform volcanic-hosted Khnaiguiyah-type Zn-Cu-Fe-Mn, and orogenic Au vein deposits, and the potential for significant resources in Fe-oxide Cu-Au (IOCG), and porphyry Cu deposits. Khnaiguiyah-type deposits formed before or during early deformation of the Al Amar group eastern sequence. Epithermal and porphyry deposits formed proximal to volcanic centers in Al Amar group western sequence. IOCG deposits are largely structurally controlled and hosted by group-1 intrusions and Al Amar group volcanic rocks in the western part of the terrane. Orogenic gold veins are largely associated with north-striking faults, particularly in and near the AAF, and are presumably related to amalgamation of the Ar Rayn and Ad Dawadimi terranes. Geologic, structural, and metallogenic

Electroless nickel plating of arc discharge synthesized carbon nanotubes for metal matrix composites

International Nuclear Information System (INIS)

Jagannatham, M.; Sankaran, S.; Prathap, Haridoss

2015-01-01

Highlights: • Electroless Ni coatings have been performed on CNTs for various deposition times. • The deposition of nickel increased with increase in deposition time. • A deposition time of 60 min has been optimum for uniform coating of Ni on CNTs. • The CNTs with uniform coating of Ni are potential for reinforcements in composites. • Electroless nickel coatings are determined to be super paramagnetic behavior. - Abstract: Electroless nickel (EN) plating was performed on arc discharge synthesized multiwalled carbon nanotubes for various deposition times. X-ray diffraction (XRD), Transmission electron microscopy (TEM), and Raman spectroscopy characterization techniques are used to identify the presence of nickel deposition on the carbon nanotubes (CNTs) and the degree of graphitization. The results indicate that impurities are less in the purified CNTs as compared to raw carbon soot. Increasing deposition time up to 60 min increases uniform deposition of nickel throughout the length of the CNTs. However, for deposition time longer than 60 min, nickel particles are seen separated from the surface of the CNTs. Uniformly coated nickel CNTs throughout their length are potential candidates for reinforcements in composite materials. Magnetic properties of the nickel coated CNTs, with deposition time of 30 and 60 min were also evaluated. The magnetic saturation of nickel coated CNTs with deposition time of 30 min is less compared to nickel coated CNTs with deposition time of 60 min

Electroless nickel plating of arc discharge synthesized carbon nanotubes for metal matrix composites

Energy Technology Data Exchange (ETDEWEB)

Jagannatham, M.; Sankaran, S.; Prathap, Haridoss, E-mail: prathap@iitm.ac.in

2015-01-01

Highlights: • Electroless Ni coatings have been performed on CNTs for various deposition times. • The deposition of nickel increased with increase in deposition time. • A deposition time of 60 min has been optimum for uniform coating of Ni on CNTs. • The CNTs with uniform coating of Ni are potential for reinforcements in composites. • Electroless nickel coatings are determined to be super paramagnetic behavior. - Abstract: Electroless nickel (EN) plating was performed on arc discharge synthesized multiwalled carbon nanotubes for various deposition times. X-ray diffraction (XRD), Transmission electron microscopy (TEM), and Raman spectroscopy characterization techniques are used to identify the presence of nickel deposition on the carbon nanotubes (CNTs) and the degree of graphitization. The results indicate that impurities are less in the purified CNTs as compared to raw carbon soot. Increasing deposition time up to 60 min increases uniform deposition of nickel throughout the length of the CNTs. However, for deposition time longer than 60 min, nickel particles are seen separated from the surface of the CNTs. Uniformly coated nickel CNTs throughout their length are potential candidates for reinforcements in composite materials. Magnetic properties of the nickel coated CNTs, with deposition time of 30 and 60 min were also evaluated. The magnetic saturation of nickel coated CNTs with deposition time of 30 min is less compared to nickel coated CNTs with deposition time of 60 min.

ALICE-ARC integration

International Nuclear Information System (INIS)

Anderlik, C; Gregersen, A R; Kleist, J; Peters, A; Saiz, P

2008-01-01

AliEn or Alice Environment is the Grid middleware developed and used within the ALICE collaboration for storing and processing data in a distributed manner. ARC (Advanced Resource Connector) is the Grid middleware deployed across the Nordic countries and gluing together the resources within the Nordic Data Grid Facility (NDGF). In this paper we will present our approach to integrate AliEn and ARC, in the sense that ALICE data management and job processing can be carried out on the NDGF infrastructure, using the client tools available in AliEn. The inter-operation has two aspects, one is the data management part and the second the job management aspect. The first aspect was solved by using dCache across NDGF to handle data. Therefore, we will concentrate on the second part. Solving it, was somewhat cumbersome, mainly due to the different computing models employed by AliEn and ARC. AliEN uses an Agent based pull model while ARC handles jobs through the more 'traditional' push model. The solution comes as a module implementing the functionalities necessary to achieve AliEn job submission and management to ARC enabled sites

Influence factors of photocatalytic activity of the filter media modified by TiO2

Directory of Open Access Journals (Sweden)

Shen Rongyan

2014-01-01

Full Text Available The gangue filter media was modified by the titanium dioxide (TiO2 through the liquid phase deposition method. Some influence factors of photocatalytic activity were investigated, including the mole ratio of initial solution, the water bath temperature, the deposition time, the calcination temperature, and the heat preservation time of calcination. The morphology of the film was examined by SEM, EDS, and crystallite structure by X-Ray Diffraction (XRD. The SEM, EDS, and XRD data showed that new TiO2 crystal was found in the modified filter media. And the specific surface area of the modified filter media greatly increased. By the orthogonal experiment, the optimum parameters of modification were (NH42TiF6:H3BO3=1:2, water bath temperature of 80ºC, deposition time of 5h, calcination temperature of 500ºC, and 1h heat preservation time of calcination. Under above conditions, the heavy nitrogen wastewater of 1589.94 mg/L COD and 18750 times chroma was treated by the modified filter media. After 1h catalytic reaction, the decolorization rate and COD removal rate reached 65.89% and 47.87%, respectively.

Data assimilation in the early phase: Kalman filtering RIMPUFF

International Nuclear Information System (INIS)

Astrup, P.; Turcanu, C.; Puch, R.O.; Palma, C.R.; Mikkelsen, T.

2004-09-01

In the framework of the DAONEM project (Data Assimilation for Off-site Nuclear Emergency Management), a data assimilation module, ADUM (Atmospheric Dispersion Updating Module), for the mesoscale atmospheric dispersion program RIMPUFF (Risoe Mesoscale Puff model) part of the early-phase programs of RODOS (Realtime Online DecisiOn Support system for nuclear emergencies) has been developed. It is built on the Kalman filtering algorithm and it assimilates 10-minute averaged gamma dose rates measured at ground level stations. Since the gamma rates are non-linear functions of the state vector variables, the applied Kalman filter is the so-called Extended Kalman filter. In more ways the implementation is non standard: 1) the number of state vector variables varies with time, and 2) the state vector variables are prediction updated with 1-minute time steps but only Kalman filtered every 10 minutes, and this based on time averaged measurements. Given reasonable conditions, i.e. a spatially dense distribution of gamma monitors and a realistic wind field, the developed ADUM module is found to be able to enhance the prediction of the gamma dose field. Based on some of the Kalman filtering parameters, another module, ToDeMM, has been developed for providing the late-phase DeMM (Deposition Monitoring Module) of RODOS with an ensemble of fields of ground level air concentrations and wet deposited material. This accounts for the uncertainty estimation of this kind of quantities as calculated by RIMPUFF for use by DeMM. (au)

Dry deposition study using filter packs at a rural and an urban monitoring sites

International Nuclear Information System (INIS)

Siti Mariam Sumari; Rusdin Laiman; Kantasamy, Nesamalar; Sinyaw, S.U.

2008-01-01

Air samples were collected from 2004 to 2005 using four-staged filter packs at an urban site Petaling Jaya (PJ) and a rural-agricultural site Tanah Rata (TR). The samples were analysed for reactive gases consisting of NH 3 , HNO 3 , HCL and SO 2 while the aerosol components were analysed for SO 4 2- , NO 3 - , Cl - , Na + , K + , Ca 2+ , Mg 2+ and NH 4 + . For both PJ and TR, analysis indicates the dry deposition was dominated by the gaseous components. They range from about 78 % to 80 % of total compositions for urban PJ and 59 % to 63 % for rural TR. Among the four reactive gases, NH 3 is the most dominating component at both sites. Elevated NH 3 concentration in TR was mainly attributed to the use of nitrogenous fertilizer. For PJ high NH 3 could be due to local air pollution created by industries as well as agricultural activities. The acidic species associated with SO x and NO x are typically more abundant at PJ than TR. Their presence, and for most other chemical species, show similar increasing trend, and this reflect the growing use of fossil fuels associated with urbanization and industrialization, especially for PJ. (author)

High-Power 365 nm UV LED Mercury Arc Lamp Replacement for Photochemistry and Chemical Photolithography.

Science.gov (United States)

Hölz, K; Lietard, J; Somoza, M M

2017-01-03

Ultraviolet light emitting diodes (UV LEDs) have become widespread in chemical research as highly efficient light sources for photochemistry and photopolymerization. However, in more complex experimental setups requiring highly concentrated light and highly spatially resolved patterning of the light, high-pressure mercury arc lamps are still widely used because they emit intense UV light from a compact arc volume that can be efficiently coupled into optical systems. Advances in the deposition and p -type doping of gallium nitride have recently permitted the manufacture of UV LEDs capable of replacing mercury arc lamps also in these applications. These UV LEDs exceed the spectral radiance of mercury lamps even at the intense I-line at 365 nm. Here we present the successful exchange of a high-pressure mercury arc lamp for a new generation UV LED as a light source in photolithographic chemistry and its use in the fabrication of high-density DNA microarrays. We show that the improved light radiance and efficiency of these LEDs offer substantial practical, economic and ecological advantages, including faster synthesis, lower hardware costs, very long lifetime, an >85-fold reduction in electricity consumption and the elimination of mercury waste and contamination.

Influence of Nitrogen Flow Rate on Friction Coefficient and Surface Roughness of TiN Coatings Deposited on Tool Steel Using Arc Method

Science.gov (United States)

Hamzah, Esah; Ourdjini, Ali; Ali, Mubarak; Akhter, Parvez; Hj. Mohd Toff, Mohd Radzi; Abdul Hamid, Mansor

In the present study, the effect of various N2 gas flow rates on friction coefficient and surface roughness of TiN-coated D2 tool steel was examined by a commercially available cathodic arc physical vapor deposition (CAPVD) technique. A Pin-on-Disc test was carried out to study the Coefficient of friction (COF) versus sliding distance. A surface roughness tester measured the surface roughness parameters. The minimum values for the COF and surface roughness were recorded at a N2 gas flow rate of 200 sccm. The increase in the COF and surface roughness at a N2 gas flow rate of 100 sccm was mainly attributed to an increase in both size and number of titanium particles, whereas the increase at 300 sccm was attributed to a larger number of growth defects generated during the coating process. These ideas make it possible to optimize the coating properties as a function of N2 gas flow rate for specific applications, e.g. cutting tools for automobiles, aircraft, and various mechanical parts.

Silica nanoparticles produced by DC arc plasma from a solid raw materials

Science.gov (United States)

Kosmachev, P. V.; Vlasov, V. A.; Skripnikova, N. K.

2017-05-01

Plasma synthesis of SiO2 nanoparticles in experimental atmospheric pressure plasma reactor on the basis of DC arc plasma generator was presented in this paper. Solid high-silica raw materials such as diatomite from Kamyshlovskoye deposit in Russia, quartzite from Chupinskoye deposit in Russia and milled window glass were used. The obtained nanoparticles were characterized based on their morphology, chemical composition and size distribution. Scanning electron microscopy, laser diffractometry, nitrogen absorption (Brunauer-Emmett-Teller method), X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy were used to characterize the synthesized products. The obtained silica nanoparticles are agglomerated, have spherical shape and primary diameters between 10-300 nm. All samples of synthesized nanopowders were compared with commercial nanopowders.

Potential for Sulfide Mineral Deposits in Australian Waters

Science.gov (United States)

McConachy, Timothy F.

The world is witnessing a paradigm shift in relation to marine mineral resources. High-value seafloor massive sulfides at active convergent plate boundaries are attracting serious commercial attention. Under the United Nations Convention on the Law of the Sea, maritime jurisdictional zones will increase by extending over continental margins and ocean basins. For Australia, this means a possible additional 3.37 million km2 of seabed. Australia's sovereign responsibility includes, amongst other roles, the management of the exploitation of nonliving resources and sea-bed mining. What, therefore, is the potential in Australia's marine jurisdiction for similar deposits to those currently attracting commercial attention in neighboring nations and for other types/styles of sulfide deposits? A preliminary review of opportunities suggests the following: (i) volcanogenic copper—lead—zinc—silver—gold mineralization in fossil arcs and back arcs in eastern waters Norfolk Ridge and the Three Kings Ridge; (ii) Mississippi Valley-type lead—zinc—silver mineralization in the NW Shelf area; (iii) ophiolite-hosted copper mineralization in the Macquarie Ridge Complex in the Southern Ocean; and (iv) submerged extensions of prospective land-based terranes, one example being offshore Gawler Craton for iron oxide—copper—gold deposits. These areas would benefit from pre-competitive surveys of detailed swath bathymetry mapping, geophysical surveys, and sampling to help build a strategic inventory of future seafloor mineral resources for Australia.

Long-term passive restoration following fluvial deposition of sulphidic copper tailings: nature filters out the solutions.

Science.gov (United States)

Nikolic, Nina; Böcker, Reinhard; Nikolic, Miroslav

2016-07-01

Despite the growing popularity of ecological restoration approach, data on primary succession on toxic post-mining substrates, under site environmental conditions which considerably differ from the surrounding environment, are still scarce. Here, we studied the spontaneous vegetation development on an unusual locality created by long-term and large-scale fluvial deposition of sulphidic tailings from a copper mine in a pronouncedly xerothermic, calcareous surrounding. We performed multivariate analyses of soil samples (20 physical and chemical parameters) and vegetation samples (floristic and structural parameters in three types of occurring forests), collected along the pollution gradients throughout the affected floodplain. The nature can cope with two types of imposed constraints: (a) excessive Cu concentrations and (b) very low pH, combined with nutrient deficiency. The former will still allow convergence to the original vegetation, while the latter will result in novel, depauperate assemblages of species typical for cooler and moister climate. Our results for the first time demonstrate that with the increasing severity of environmental filtering, the relative importance of the surrounding vegetation for primary succession strongly decreases.

Arc-weld pool interactions

International Nuclear Information System (INIS)

Glickstein, S.S.

1978-08-01

The mechanisms involved in arc-weld pool interactions are extremely complex and no complete theory is presently available to describe much of the phenomena observed during welding. For the past several years, experimental and analytical studies have been undertaken at the Bettis Atomic Power Laboratory to increase basic understanding of the gas tungsten arc welding process. These studies have included experimental spectral analysis of the arc in order to determine arc temperature and analytical modeling of the arc and weld puddle. The investigations have been directed toward determining the cause and effects of variations in the energy distribution incident upon the weldment. In addition, the effect of weld puddle distortion on weld penetration was investigated, and experimental and analytical studies of weld process variables have been undertaken to determine the effects of the variables upon weld penetration and configuration. A review of the results and analysis of these studies are presented

Volcanism in slab tear faults is larger than in island-arcs and back-arcs.

Science.gov (United States)

Cocchi, Luca; Passaro, Salvatore; Tontini, Fabio Caratori; Ventura, Guido

2017-11-13

Subduction-transform edge propagators are lithospheric tears bounding slabs and back-arc basins. The volcanism at these edges is enigmatic because it is lacking comprehensive geological and geophysical data. Here we present bathymetric, potential-field data, and direct observations of the seafloor on the 90 km long Palinuro volcanic chain overlapping the E-W striking tear of the roll-backing Ionian slab in Southern Tyrrhenian Sea. The volcanic chain includes arc-type central volcanoes and fissural, spreading-type centers emplaced along second-order shears. The volume of the volcanic chain is larger than that of the neighbor island-arc edifices and back-arc spreading center. Such large volume of magma is associated to an upwelling of the isotherms due to mantle melts upraising from the rear of the slab along the tear fault. The subduction-transform edge volcanism focuses localized spreading processes and its magnitude is underestimated. This volcanism characterizes the subduction settings associated to volcanic arcs and back-arc spreading centers.

Effect of arc suppression on the physical properties of low temperature dc magnetron sputtered tantalum thin films

International Nuclear Information System (INIS)

Subrahmanyam, A.; Valleti, Krishna; Joshi, Srikant V.; Sundararajan, G.

2007-01-01

Arcing is a common phenomenon in the sputtering process. Arcs and glow discharges emit electrons which may influence the physical properties of films. This article reports the properties of tantalum (Ta) thin films prepared by continuous dc magnetron sputtering in normal and arc-suppression modes. The substrate temperature was varied in the range of 300-673 K. The tantalum films were ∼1.8 μm thick and have good adherence to 316 stainless steel and single-crystal silicon substrates. The phase of the Ta thin film determines the electrical and tribological properties. The films deposited at 300 K using both methods were crystallized in a tetragonal structure (β phase) with a smooth surface (grain size of ∼10 nm) and exhibited an electrical resistivity of ∼194 μΩ cm and a hardness of ∼20 GPa. When the substrate temperature was 473 K and higher, the arc-suppression mode appears to influence the films to crystallize in the α phase with a grain size of ∼40 nm, whereas the normal power mode gave mixed phases β and α beyond 473 K, the arc-suppression mode yields larger grain sizes in the Ta thin films and the hardness decreases. These changes in the physical properties in arc-suppression mode are attributed to either the change in plasma characteristics or the energetic particle bombardment onto the substrate, or both

The deposition of gold nanoparticles in MWCNT forests

Science.gov (United States)

de Jong, Franciscus; Buffet, Adeline; Schlueter, Michael

2015-11-01

The deposition, i.e. transport and attachment, of small-sized particles is a basic process, on which many applications are based. The innumerable applications range from biology and medicine to engineering. Due to their promising mechanical properties multi-walled carbon nanotubes (MWCNTs) have gained increasing popularity in the past decade. A large number of dense packed vertically aligned MWCNTs form a so-called MWCNT forest. In our study we functionalized the MWCNT forest to filter gold nanoparticles from a colloidal suspension. An experimental investigation was carried out in which the particle deposition kinetics was locally determined with small-angle X-ray scattering (SAXS). Furthermore, inductively coupled plasma atomic emission spectroscopy (ICP-AES) was used to verify the local observations. It was concluded that both, SAXS and ICP-AES investigations shows very good agreement. Furthermore, an analytical deposition model was developed based on the DLVO-theory. The experimental and theoretical investigation presented here give insight in the deposition kinetics within a MWCNT forest. The results open up pathways to optimize MWCNT forests for filtering purposes.

Electric arc hydrogen heaters

International Nuclear Information System (INIS)

Zasypin, I.M.

2000-01-01

The experimental data on the electric arc burning in hydrogen are presented. Empirical and semiempirical dependences for calculating the arc characteristics are derived. An engineering method of calculating plasma torches for hydrogen heating is proposed. A model of interaction of a hydrogen arc with a gas flow is outlined. The characteristics of plasma torches for heating hydrogen and hydrogen-bearing gases are described. (author)

Oxidation State of Iron in the Izu-Bonin Arc Initial Magma and Its Influence Factors

Science.gov (United States)

Li, H.; Arculus, R. J.; Brandl, P. A.; Hamada, M.; Savov, I. P.; Zhu, S.; Hickey-Vargas, R.; Tepley, F. J., III; Meffre, S.; Yogodzinski, G. M.; McCarthy, A.; Barth, A. P.; Kanayama, K.; Kusano, Y.; Sun, W.

2014-12-01

The redox state of mantle-derived magmas is a controversial issue, especially whether island arc basalts are more oxidized than those from mid-ocean ridges. Usually, arc magmas have higher Fe3+/Fe2+ and calculated oxygen fugacity (fO2) than mid-ocean ridge basalts (MORB). It is the high fO2 of arc magma that apparently delays onset of sulfide fractionation and sequestration of precious/base metals thereby facilitating the formation of many giant gold-copper deposits typically associated with subduction zones. But due to a paucity of Fe3+/Fe2+ data for primary mantle-derived arc magmas, the cause for high fO2 of these magma types is still controversial; causes may include inter alia subduction-released oxidized material addition to the mantle wedge source of arc magma, partial melting of subducted slab, and redox changes occurring during ascent of the magma. Fortunately, IODP expedition 351 drilling at IODP Site U1438 in the Amami-Sankaku Basin of the northwestern Philipine Sea, adjacent to the proto-Izu-Bonin Arc at the Kyushu-Palau Ridge (KPR), recovered not only volcaniclastics derived from the inception of Izu-Bonin Mariana (IBM) arc in the Eocene, but also similar materials for the Arc's subsequent evolution through to the Late Oligocene and abandonment of the KPR as a remnant arc. Samples of the pre-Arc oceanic crustal basement were also recovered enabling us to determine the fO2of the mantle preceding arc inception. As the oxidation state of iron in basaltic glass directly relates to the fO2 , the Fe3+/∑Fe ratio [Fe3+/(Fe3++ Fe2+)] of basaltic glass are quantified by synchrotron-facilitated micro X-ray Absorption Near Edge Structure (XANES) spectroscopy to reflect its fO2. Fe K-edge µ-XANES spectra were recorded in fluorescence mode at Beamline 15U1, Shanghai Synchrotron Radiation Facility (SSRF). Synthetic silicate glass with known Fe3+/∑Fe ratio was used in data handling. The experimental results as well as preliminary data from IODP Expedition 351

1020 steel coated with Ti/TiN by Cathodic Arc and Ion Implantation

International Nuclear Information System (INIS)

Bermeo, F; Quintana, J P; Kleiman, A; Márquez, A; Sequeda, F

2017-01-01

TiN coatings have been widely studied in order to improve mechanical properties of steels. In this work, thin Ti/TiN films were prepared by plasma based immersion ion implantation and deposition (PBII and D) with a cathodic arc on AISI 1020 steel substrates. Substrates were exposed to the discharge during 1 min in vacuum for the deposition of a Tiunderlayer with the aim of improving the adhesion to the substrate. Then, a TiN layer was deposited during 6 min in a nitrogen environment at a pressure of 3xl0 -4 mbar. Samples were obtained at room temperature and at 300 °C, and with or without ion implantation in order to analyze differences between the effects of each treatment on the tribological properties. The mechanical and tribological properties of the films were characterized. The coatings deposited by PBII and D at 300 °C presented the highest hardness and young modulus, the best wear resistance and corrosion performance. (paper)

Plasma and Ion Assistance in Physical Vapor Deposition: A Historical Perspective

International Nuclear Information System (INIS)

Anders, Andre

2007-01-01

Deposition of films using plasma or plasma-assist can be traced back surprisingly far, namely to the 18th century for arcs and to the 19th century for sputtering. However, only since the 1960s the coatings community considered other processes than evaporation for large scale commercial use. Ion Plating was perhaps the first important process, introducing vapor ionization and substrate bias to generate a beam of ions arriving on the surface of the growing film. Rather independently, cathodic arc deposition was established as an energetic condensation process, first in the former Soviet Union in the 1970s, and in the 1980s in the Western Hemisphere. About a dozen various ion-based coating technologies evolved in the last decades, all characterized by specific plasma or ion generation processes. Gridded and gridless ion sources were taken from space propulsion and applied to thin film deposition. Modeling and simulation have helped to make plasma and ions effects to be reasonably well understood. Yet--due to the complex, often non-linear and non-equilibrium nature of plasma and surface interactions--there is still a place for the experience plasma 'sourcerer'

Preliminary Analytical Reviews on the Performance of Fibrous Filter

International Nuclear Information System (INIS)

Choi, Yu Jung; Hong, Tae Hyub; Kim, Hyeong-Taek

2015-01-01

The wet type Containment Filtered Vent System (CFVS) is composed of a tank including nozzles in a liquid pool, moisture separators, and a few dry filters such as a metal fiber filter and a molecular sieve. After injecting gases from the containment into the CFVS under severe accident conditions, the CFVS will release decontaminated radioactive materials to the environment. To protect against the release of uncontrolled fission products to the environment, we need to confirm the performance of the CFVS in terms of not only the integral capability but also the capabilities of the individual components. It is crucial to confirm the performance of the metal fiber filter in both analytical and experimental ways. Pressure drop across a filter and collection efficiency are ways to explain the performance of a fibrous filter. Based on data from the literature survey, pressure drop and collection efficiency for a single filter were calculated. The trends of pressure drop and collection efficiencies due to various deposition mechanisms of particles onto the fiber of the filters were roughly confirmed. Therefore, to obtain better quantitative predictions of the performance of the metal fiber filter, a new model able to evaluate the performance of fibrous filters under severe conditions should be developed

Direct trace-elemental analysis of urine samples by laser ablation-inductively coupled plasma mass spectrometry after sample deposition on clinical filter papers.

Science.gov (United States)

Aramendía, Maite; Rello, Luis; Vanhaecke, Frank; Resano, Martín

2012-10-16

Collection of biological fluids on clinical filter papers shows important advantages from a logistic point of view, although analysis of these specimens is far from straightforward. Concerning urine analysis, and particularly when direct trace elemental analysis by laser ablation-inductively coupled plasma mass spectrometry (LA-ICPMS) is aimed at, several problems arise, such as lack of sensitivity or different distribution of the analytes on the filter paper, rendering obtaining reliable quantitative results quite difficult. In this paper, a novel approach for urine collection is proposed, which circumvents many of these problems. This methodology consists on the use of precut filter paper discs where large amounts of sample can be retained upon a single deposition. This provides higher amounts of the target analytes and, thus, sufficient sensitivity, and allows addition of an adequate internal standard at the clinical lab prior to analysis, therefore making it suitable for a strategy based on unsupervised sample collection and ulterior analysis at referral centers. On the basis of this sampling methodology, an analytical method was developed for the direct determination of several elements in urine (Be, Bi, Cd, Co, Cu, Ni, Sb, Sn, Tl, Pb, and V) at the low μg L(-1) level by means of LA-ICPMS. The method developed provides good results in terms of accuracy and LODs (≤1 μg L(-1) for most of the analytes tested), with a precision in the range of 15%, fit-for-purpose for clinical control analysis.

Geological principles of exploration for sandstone-hosted uranium deposits

International Nuclear Information System (INIS)

Le Roux, J.P.

1982-10-01

Although the importance of sandstone-hosted uranium deposits has seemingly faded in recent years due to the discovery of large, high -grade deposits elsewhere, a forecasted energy shortage in the near future will probably necessitate a new look at sedimentary basins as a source of uranium. Back-arc basins adjacent to calcalkaline source areas are especially favourable if they are filled with fluvial, post-Devonian sediments. Syn- and post-depositional tectonics play an important role in the sedimentation-mineralisation process and should be investigated. The oxidation-reduction state of the sandstones is a valid prospecting tool. Sedimentological environments govern the permeability and vegetal matter content of sandstones and directly control uranium mineralisation

Conversion of Methane to C2 Hydrocarbons and Hydrogen Using a Gliding Arc Reactor

International Nuclear Information System (INIS)

Hu Shuanghui; Wang Baowei; Lv Yijun; Yan Wenjuan

2013-01-01

Methane conversion has been studied using gliding arc plasma in the presence of argon. The process was conducted at atmospheric pressure and ambient temperature. The focus of this research was to develop a process of converting methane to C 2 hydrocarbons and hydrogen. The main parameters, including the CH 4 /Ar mole ratio, the CH 4 flow rate, the input voltage, and the minimum electrode gap, were varied to investigate their effects on methane conversion rate, product distribution, energy consumption, carbon deposit, and reaction stability. The specific energy requirement (SER) was used to express the energy utilization efficiency of the process and provided a practical guidance for optimizing reaction conditions for improving energy efficiency. It was found that the carbon deposition was not conducive to methane conversion, and the gliding arc plasma discharge reached a stable state twelve minutes later. Optimum conditions for methane conversion were suggested. The maximum methane conversion rate of 43.39% was obtained under the optimum conditions. Also, C 2 hydrocarbons selectivity, C 2 hydrocarbons yield, H 2 selectivity, H 2 yield and SER were 87.20%, 37.83%, 81.28%, 35.27%, and 2.09 MJ/mol, respectively.

Highly zone-dependent synthesis of different carbon nanostructures using plasma-enhanced arc discharge technique

Energy Technology Data Exchange (ETDEWEB)

Kumar, Rajesh, E-mail: rajeshbhu1@gmail.com [Yonsei University, Department of Materials Science & Engineering (Korea, Republic of); Singh, Rajesh Kumar, E-mail: rksbhu@gmail.com [Banaras Hindu University, Department of Applied Physics, Indian Institute of Technology (India); Dubey, Pawan Kumar [University of Allahabad, Nanotechnology Application Centre (India); Yadav, Ram Manohar [Rice University, Department of Materials Science and Nano Engineering (United States); Singh, Dinesh Pratap [Universidad de Santiago de Chile, Departamento de Física (Chile); Tiwari, R. S.; Srivastava, O. N. [Banaras Hindu University, Department of Physics (India)

2015-01-15

Three kinds of carbon nanostructures, i.e., graphene nanoflakes (GNFs), multi walled carbon nanotubes (MWCNTs), and spherical carbon nanoparticles (SCNPs) were comparatively investigated in one run experiment. These carbon nanostructures are located at specific location inside the direct current plasma-assisted arc discharge chamber. These carbon nanomaterials have been successfully synthesized using graphite as arcing electrodes at 400 torr in helium (He) atmosphere. The SCNPs were found in the deposits formed on the cathode holder, in which highly curled graphitic structure are found in majority. The diameter varies from 20 to 60 nm and it also appears that these particles are self-assembled to each other. The MWCNTs with the diameter of 10–30 nm were obtained which were present inside the swelling portion of cathode deposited. These MWCNTs have 14–18 graphitic layers with 3.59 Å interlayer spacing. The GNFs have average lateral sizes of 1–5 μm and few of them are stacked layers and shows crumpled like structure. The GNFs are more stable at low temperature (low mass loss) but SCNPs have low mass loss at high temperature.

Space-qualified optical thin films by ion-beam-assisted deposition

International Nuclear Information System (INIS)

Hsiao, C.N.; Chen, H.P.; Chiu, P.K.; Lin, Y.W.; Chen, F.Z.; Tsai, D.P.

2013-01-01

Optical interference coatings designed for use in a space-grade multispectral assembly in a complementary metal-oxide‐semiconductor sensor were deposited on glass by ion-beam-assisted deposition for a Cassegrain-type space-based remote-sensing platform. The patterned multispectral assembly containing blue, green, red, near infrared, and panchromatic multilayer high/low alternated dielectric band-pass filter arrays in a single chip was fabricated by a mechanical mask and the photolithography process. The corresponding properties of the films were investigated by in situ optical monitoring and spectrometry. It was found that the optical properties were significantly improved by employing ion-beam-assisted deposition. The average transmittances were above 88% for the multispectral assembly, with a rejection transmittance of less than 1% in the spectral range 350–1100 nm. To estimate the optical stability of optical coatings for aerospace applications, a space environment assuming a satellite orbiting the Earth at an altitude of near 800 km was simulated by a Co 60 gamma (γ) radiation test. - Highlights: ►Parameters of optical filters were optimized by using admittance loci analysis. ►Higher index of refraction of films prepared by ion beam assisted deposition. ►The dielectric filters have acceptable resistance after γ radiation exposure

Study of the ionization rate of the released deuterium in vacuum arc discharges with metal deuteride cathodes

Science.gov (United States)

Liu, Fei-Xiang; Long, Ji-Dong; Zheng, Le; Dong, Pan; Li, Chen; Chen, Wei

2018-02-01

The ionization rate of the released deuterium from a metal deuteride cathode in vacuum arc discharges is investigated by both experiments and modeling analysis. Experimental results show that the deuterium ionization rate increases from 2% to 30% with the increasing arc current in the range of 2-100 A. Thus the full ionization assumption, as is widely used in arc plasma simulations, is not satisfied for the released deuterium at low discharge current. According to the modeling results, the neutral-to-ion conversion efficiency for the deuterium traveling across the cathodic spot region can be significantly less than one, due to the fast plasma expansion and rarefaction in the vacuum. In addition, the model also reveals that, unlike the metal atoms which are mainly ionized in the sheath region and flow back to the cathode, the deuterium ionization primarily occurs in the quasi-neutral region and moves towards the anode. Consequently, the cathodic sheath layer acts like a filter that increases the deuterium fraction beyond the sheath region.

An analysis of the ArcCHECK-MR diode array's performance for ViewRay quality assurance.

Science.gov (United States)

Ellefson, Steven T; Culberson, Wesley S; Bednarz, Bryan P; DeWerd, Larry A; Bayouth, John E

2017-07-01

The ArcCHECK-MR diode array utilizes a correction system with a virtual inclinometer to correct the angular response dependencies of the diodes. However, this correction system cannot be applied to measurements on the ViewRay MR-IGRT system due to the virtual inclinometer's incompatibility with the ViewRay's multiple simultaneous beams. Additionally, the ArcCHECK's current correction factors were determined without magnetic field effects taken into account. In the course of performing ViewRay IMRT quality assurance with the ArcCHECK, measurements were observed to be consistently higher than the ViewRay TPS predictions. The goals of this study were to quantify the observed discrepancies and test whether applying the current factors improves the ArcCHECK's accuracy for measurements on the ViewRay. Gamma and frequency analysis were performed on 19 ViewRay patient plans. Ion chamber measurements were performed at a subset of diode locations using a PMMA phantom with the same dimensions as the ArcCHECK. A new method for applying directionally dependent factors utilizing beam information from the ViewRay TPS was developed in order to analyze the current ArcCHECK correction factors. To test the current factors, nine ViewRay plans were altered to be delivered with only a single simultaneous beam and were measured with the ArcCHECK. The current correction factors were applied using both the new and current methods. The new method was also used to apply corrections to the original 19 ViewRay plans. It was found the ArcCHECK systematically reports doses higher than those actually delivered by the ViewRay. Application of the current correction factors by either method did not consistently improve measurement accuracy. As dose deposition and diode response have both been shown to change under the influence of a magnetic field, it can be concluded the current ArcCHECK correction factors are invalid and/or inadequate to correct measurements on the ViewRay system. © 2017 The

Flat panel detector-based cone beam computed tomography with a circle-plus-two-arcs data acquisition orbit: Preliminary phantom study

International Nuclear Information System (INIS)

Ning Ruola; Tang Xiangyang; Conover, David; Yu Rongfeng

2003-01-01

Cone beam computed tomography (CBCT) has been investigated in the past two decades due to its potential advantages over a fan beam CT. These advantages include (a) great improvement in data acquisition efficiency, spatial resolution, and spatial resolution uniformity, (b) substantially better utilization of x-ray photons generated by the x-ray tube compared to a fan beam CT, and (c) significant advancement in clinical three-dimensional (3D) CT applications. However, most studies of CBCT in the past are focused on cone beam data acquisition theories and reconstruction algorithms. The recent development of x-ray flat panel detectors (FPD) has made CBCT imaging feasible and practical. This paper reports a newly built flat panel detector-based CBCT prototype scanner and presents the results of the preliminary evaluation of the prototype through a phantom study. The prototype consisted of an x-ray tube, a flat panel detector, a GE 8800 CT gantry, a patient table and a computer system. The prototype was constructed by modifying a GE 8800 CT gantry such that both a single-circle cone beam acquisition orbit and a circle-plus-two-arcs orbit can be achieved. With a circle-plus-two-arcs orbit, a complete set of cone beam projection data can be obtained, consisting of a set of circle projections and a set of arc projections. Using the prototype scanner, the set of circle projections were acquired by rotating the x-ray tube and the FPD together on the gantry, and the set of arc projections were obtained by tilting the gantry while the x-ray tube and detector were at the 12 and 6 o'clock positions, respectively. A filtered backprojection exact cone beam reconstruction algorithm based on a circle-plus-two-arcs orbit was used for cone beam reconstruction from both the circle and arc projections. The system was first characterized in terms of the linearity and dynamic range of the detector. Then the uniformity, spatial resolution and low contrast resolution were assessed using

Consolidating NASA's Arc Jets

Science.gov (United States)

Balboni, John A.; Gokcen, Tahir; Hui, Frank C. L.; Graube, Peter; Morrissey, Patricia; Lewis, Ronald

2015-01-01

The paper describes the consolidation of NASA's high powered arc-jet testing at a single location. The existing plasma arc-jet wind tunnels located at the Johnson Space Center were relocated to Ames Research Center while maintaining NASA's technical capability to ground-test thermal protection system materials under simulated atmospheric entry convective heating. The testing conditions at JSC were reproduced and successfully demonstrated at ARC through close collaboration between the two centers. New equipment was installed at Ames to provide test gases of pure nitrogen mixed with pure oxygen, and for future nitrogen-carbon dioxide mixtures. A new control system was custom designed, installed and tested. Tests demonstrated the capability of the 10 MW constricted-segmented arc heater at Ames meets the requirements of the major customer, NASA's Orion program. Solutions from an advanced computational fluid dynamics code were used to aid in characterizing the properties of the plasma stream and the surface environment on the calorimeters in the supersonic flow stream produced by the arc heater.

Estimation of the upper limit of aerosol nanoparticles penetration through inhomogeneous fibrous filters