WorldWideScience

Sample records for plasma process parameters

  1. Plasma Processes : Sheath and plasma parameters in a magnetized plasma system

    Indian Academy of Sciences (India)

    Bornali Singha; A Sharma; J Chutia

    2000-11-01

    The variation of electron temperature and plasma density in a magnetized 2 plasma is studied experimentally in presence of a grid placed at the middle of the system. Plasma leaks through the negatively biased grid from the source region into the diffused region. It is observed that the electron temperature increases with the magnetic field in the diffused region whereas it decreases in the source region of the system for a constant grid biasing voltage. Also, investigation is done to see the change of electron temperature with grid biasing voltage for a constant magnetic field. This is accompanied by the study of the variation of sheath structure across the grid for different magnetic field and grid biasing voltage as well. It reveals that with increasing magnetic field and negative grid biasing voltage, the sheath thickness expands.

  2. Effect of process parameters on induction plasma reactive deposition of tungsten carbide from tungsten metal powder

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Tungsten carbide deposit was made directly from tungsten metal powder through the reaction with methane in radio frequency induction plasma. Effect of major process parameters on the induction plasma reactive deposition of tungsten carbide was studied by optical microscopy, scanning electron microscopy, X-ray diffraction analysis, water displacement method, and microhardness test. The results show that methane flow rate, powder feed rate, particle size, reaction chamber pressure and deposition distance have significant influences on the phase composition, density, and microhardness of the deposit. Extra carbon is necessary to ensure the complete conversion of tungsten metal into the carbide.

  3. Self-bias Dependence on Process Parameters in Asymmetric Cylindrical Coaxial Capacitively Coupled Plasma

    CERN Document Server

    Upadhyay, J; Popović, S; Valente-Feliciano, A -M; Phillips, L; Vušković, L

    2015-01-01

    An rf coaxial capacitively coupled Ar/Cl2 plasma is applied to processing the inner wall of superconducting radio frequency cavities. A dc self-bias potential is established across the inner electrode sheath due to the surface area difference between inner and outer electrodes of the coaxial plasma. The self-bias potential measurement is used as an indication of the plasma sheath voltage asymmetry. The understanding of the asymmetry in sheath voltage distribution in coaxial plasma is important for the modification of the inner surfaces of three dimensional objects. The plasma sheath voltages were tailored to process the outer wall by providing an additional dc current to the inner electrode with the help of an external dc power supply. The dc self-bias potential is measured for different diameter electrodes and its variation on process parameters such as gas pressure, rf power and percentage of chlorine in the Ar/Cl2 gas mixture is studied. The dc current needed to overcome the self-bias potential to make it ...

  4. Parameters Optimization of Plasma Hardening Process Using Genetic Algorithm and Neural Network

    Institute of Scientific and Technical Information of China (English)

    LIU Gu; WANG Liu-ying; CHEN Gui-ming; HUA Shao-chun

    2011-01-01

    Plasma surface hardening process was performed to improve the performance of the AISI 1045 carbon steel.Experiments were carried out to characterize the hardening qualities.A predicting and optimizing model using genetic algorithm-back propagation neural network(GA-BP) was developed based on the experimental results.The non-linear relationship between properties of hardening layers and process parameters was established.The results show that the GA-BP predicting model is reliable since prediction results are in rather good agreement with measured results.The optimal properties of the hardened layer were deduced from GA.And through multi optimizations,the optimum comprehensive performances of the hardened layer were as follows:plasma arc current is 90 A,hardening speed is 2.2 m/min,plasma gas flow rate is 6.0 L/min and hardening distance is 4.3 mm.It concludes that GA-BP mode developed in this study provides a promising method for plasma hardening parameters prediction and optimization.

  5. Effect of process parameters on coating composition of cathodic-plasma-electrolysis-treated copper

    Indian Academy of Sciences (India)

    ASIYEH HABIBI; S MOHAMMAD MOUSAVI KHOIE; FARZAD MAHBOUBI; MUSTAFA URGEN

    2017-04-01

    Cathodic plasma electrolysis is a novel technique to form nanostructured layers on metallic surfaces by application of high voltage in a suitable aqueous electrolyte. In the present study, copper is treated by plasma electrolysisin 50 vol% ethanol electrolyte and coatings comprising carbon nanostructure and copper oxide are formed on the copper. The effect of some process parameters such as electrical conductivity, volume and temperature of electrolyte and ratio of anode to cathode surface area on current–voltage behaviour and subsequently coating compositions are investigated at 150V deposition voltage. The composition and morphology of these coatings are characterized by X-ray diffraction, Raman spectroscopy and scanning electron microscopy. Different current–voltage behaviours, temperatures of substrate and the contents and energies of radicals and ions around the substrate by changes in the mentioned parameters cause different compositions from 100 vol% copper oxide to different ratios of copper oxide to carbon, the structure changing from amorphous to graphitic structure in carbon and amorphous to cubic morphology in copper oxide on the substrate. Therefore, the understanding of cathodic plasma electrolysiscan be developed.

  6. Plasma polymers deposited in atmospheric pressure dielectric barrier discharges: Influence of process parameters on film properties

    Energy Technology Data Exchange (ETDEWEB)

    Fricke, Katja, E-mail: k.fricke@inp-greifswald.de [Leibniz Institute for Plasma Science and Technology e.V. (INP Greifswald), Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany); Girard-Lauriault, Pierre-Luc [Plasma Processing Laboratory, Department of Chemical Engineering, McGill University, 3610 rue University, Montreal, QC H3A 0C5 (Canada); Weltmann, Klaus-Dieter [Leibniz Institute for Plasma Science and Technology e.V. (INP Greifswald), Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany); Wertheimer, Michael R. [Department of Engineering Physics, École Polytechnique de Montréal, Box 6079, Station Centre-Ville, Montreal, QC H3C 3A7 (Canada)

    2016-03-31

    We present results on the deposition of plasma polymer (PP) films in a dielectric barrier discharge system fed with mixtures of argon or nitrogen carrier gas plus different hydrocarbon precursors, where the latter possess different carbon-to-hydrogen ratios: CH{sub 4} < C{sub 2}H{sub 6} < C{sub 2}H{sub 4} = C{sub 3}H{sub 6} < C{sub 2}H{sub 2}. The influence of precursor gas mixture and flow rate, excitation frequency, and absorbed power on PP film compositions and properties has been investigated. The discharge was characterized by electrical measurements, while the chemical compositions and structures of coatings were analysed by X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, total combustion, and elastic recoil detection analyses, the latter two for determining carbon-to-hydrogen ratios. Scanning electron microscopy was used to study the coatings' morphology, and profilometry for evaluating deposition rates. - Highlights: • Atmospheric pressure DBD is used to deposit organic hydrocarbon films. • High deposition rates can be achieved by varying the power and/or gas mixture ratio. • Process parameters affect the films' surface chemical composition and morphology. • Deposited films are not soluble in aqueous environment. • No delamination of coatings produced from argon plasma.

  7. Plasma diagnostics discharge parameters and chemistry

    CERN Document Server

    Auciello, Orlando

    1989-01-01

    Plasma Diagnostics, Volume 1: Discharge Parameters and Chemistry covers seven chapters on the important diagnostic techniques for plasmas and details their use in particular applications. The book discusses optical diagnostic techniques for low pressure plasmas and plasma processing; plasma diagnostics for electrical discharge light sources; as well as Langmuir probes. The text also describes the mass spectroscopy of plasmas, microwave diagnostics, paramagnetic resonance diagnostics, and diagnostics in thermal plasma processing. Electrical engineers, nuclear engineers, microwave engineers, che

  8. The effects of process parameters on yield and properties of iron nanoparticles from ferrocene in a low-pressure plasma

    Science.gov (United States)

    Panchal, V.; Lahoti, G.; Bhandarkar, U.; Neergat, M.

    2011-08-01

    The effects of process parameters on iron nanoparticle formation and properties while using ferrocene as a precursor in a low-pressure capacitively coupled plasma are investigated. The L18 array of the Taguchi method, followed by the L4 array, is used with the notional objective of increasing the yield of nanoparticles. A study of the size, shape and composition of the particles (using transmission electron microscopy, high-resolution transmission electron microscopy, Raman spectroscopy, x-ray diffraction, CHON and inductively coupled plasma-atomic emission spectroscopy analysis) gives an insight into the role played by various process parameters. Pressure is the most critical parameter in increasing nanoparticle yield, whereas hydrogen flow plays a key role in determining the nanoparticle size and composition. Atomic hydrogen helps in removing amorphous carbon and reducing the nanoparticle size. RF power plays an important role in the dissociation of ferrocene thus also affecting the composition. Nanoparticles obtained using optimized conditions are a mixture of Fe3O4 and Fe2O3 with cluster size 25-40 nm in diameter that are further made up of 2-4 nm crystallites. Magnetic property measurements indicate that the nanoparticles are super-paramagnetic in nature.

  9. The effects of process parameters on yield and properties of iron nanoparticles from ferrocene in a low-pressure plasma

    Energy Technology Data Exchange (ETDEWEB)

    Panchal, V; Neergat, M [Department of Energy Science and Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076 (India); Lahoti, G; Bhandarkar, U, E-mail: bhandarkar@iitb.ac.in [Department of Mechanical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076 (India)

    2011-08-31

    The effects of process parameters on iron nanoparticle formation and properties while using ferrocene as a precursor in a low-pressure capacitively coupled plasma are investigated. The L{sub 18} array of the Taguchi method, followed by the L{sub 4} array, is used with the notional objective of increasing the yield of nanoparticles. A study of the size, shape and composition of the particles (using transmission electron microscopy, high-resolution transmission electron microscopy, Raman spectroscopy, x-ray diffraction, CHON and inductively coupled plasma-atomic emission spectroscopy analysis) gives an insight into the role played by various process parameters. Pressure is the most critical parameter in increasing nanoparticle yield, whereas hydrogen flow plays a key role in determining the nanoparticle size and composition. Atomic hydrogen helps in removing amorphous carbon and reducing the nanoparticle size. RF power plays an important role in the dissociation of ferrocene thus also affecting the composition. Nanoparticles obtained using optimized conditions are a mixture of Fe{sub 3}O{sub 4} and Fe{sub 2}O{sub 3} with cluster size 25-40 nm in diameter that are further made up of 2-4 nm crystallites. Magnetic property measurements indicate that the nanoparticles are super-paramagnetic in nature.

  10. The Effect of Processing Parameters on the Performance of Spark Plasma Sintered cBN-WC-Co Composites

    Science.gov (United States)

    Mao, Cong; Zhang, Mingjun; Zhang, Jian; Tang, Kun; Gan, Hangyu; Zhang, Gaofeng

    2015-12-01

    Cubic boron nitride (cBN) particles were mixed into superfine tungsten carbide (WC), and then cBN-WC-cobalt (Co) composites were prepared using spark plasma sintering method. The influence of the processing parameters on the microstructures and the mechanical properties of the cBN-WC-Co composites were investigated. The results indicated that the cBN particles arranged uniformly and had an excellent adhesion with WC matrix. There was no evidence of phase transformation from cBN to hBN. With the increasing of the sintering temperature, the liquid-phase Co was increased and entered the micro-pores between WC and cBN particles easily. Correspondingly, the density, the flexural strength, and the hardness of the cBN-WC-Co composites also increased. With the further increasing of the sintering temperature, WC grains grew leading to the reduction of the hardness. Therefore, the hardness of the samples increased to a maximum value of 2978 HV at 1250 °C, and then decreased with the sintering temperature. The experimental results also showed that the density, the flexural strength, and the hardness of cBN-WC-Co composites increased with the holding time, whereas the hardness presented a decreasing tendency when the holding time exceeded 7 min.

  11. Plasma processing for VLSI

    CERN Document Server

    Einspruch, Norman G

    1984-01-01

    VLSI Electronics: Microstructure Science, Volume 8: Plasma Processing for VLSI (Very Large Scale Integration) discusses the utilization of plasmas for general semiconductor processing. It also includes expositions on advanced deposition of materials for metallization, lithographic methods that use plasmas as exposure sources and for multiple resist patterning, and device structures made possible by anisotropic etching.This volume is divided into four sections. It begins with the history of plasma processing, a discussion of some of the early developments and trends for VLSI. The second section

  12. Plasma diagnostics in plasma processing for nanotechnology and nanolevel chemistry

    Directory of Open Access Journals (Sweden)

    Hiroshi Akatsuka

    2004-01-01

    Full Text Available The author reviews the role of various plasma diagnostics in plasma processing for nanotechnology, and points out some essential methods of spectroscopic methods to diagnose plasmas for nanoprocessing. Two experimental examples are discussed between the characteristics of nanomaterials and plasma parameters. One is measurement of rotation temperature in processing of carbon nanotube. The other is that of vibrational temperature in surface nitriding of titanium by nitrogen plasma processing. We summarize what to measure and how to measure them from the technical viewpoint of plasma diagnostics.

  13. Ellagitannins and Flavan-3-ols from Raspberry Pomace Modulate Caecal Fermentation Processes and Plasma Lipid Parameters in Rats

    Directory of Open Access Journals (Sweden)

    Bartosz Fotschki

    2015-12-01

    Full Text Available Raspberry pomace is a source of polyphenols, which nutritional and health promoting properties are not sufficiently known. The aim of this 8-weeks study was to scrutinize if raspberry extracts (REs with different ellagitannins to flavan-3-ols ratios might favorably affect the caecal fermentation processes and blood lipid profile in rats. Forty male Wistar rats were fed with a standard diet or its modification with two types of REs (E1 and E2 characterized by different ratios of ellagitannins to flavan-3-ols (7.7 and 3.1 for E1 and E2, respectively and added to a diet at two dosages of polyphenolic compounds (0.15 and 0.30% of a diet; L and H treatments, respectively. Irrespective of polyphenols dietary level, both REs reduced the activity of bacterial β-glucuronidase, increased production of butyric acid in the caecum and reduced triacylglycerols in blood plasma. The E1 treatment at both dosages caused more effective reduction in the concentration of ammonia and elevated acetate level in the caecal digesta than E2. On the other hand, only the E2 treatment lowered value of the atherogenic index when compared with control group. When comparing dosages of REs, a higher one was more potent to reduce the activity of bacterial β-glucosidase, β-, α-galactosidase and lowered value of the HDL profile in plasma. To conclude, REs may favorably modulate the activity of the caecal microbiota and blood lipid profile in rats; however, the intensity of these effects may be related to the dosages of dietary polyphenols and to their profile, e.g., ellagitannins to flavan-3-ols ratio.

  14. Ellagitannins and Flavan-3-ols from Raspberry Pomace Modulate Caecal Fermentation Processes and Plasma Lipid Parameters in Rats.

    Science.gov (United States)

    Fotschki, Bartosz; Juśkiewicz, Jerzy; Sójka, Michał; Jurgoński, Adam; Zduńczyk, Zenon

    2015-12-21

    Raspberry pomace is a source of polyphenols, which nutritional and health promoting properties are not sufficiently known. The aim of this 8-weeks study was to scrutinize if raspberry extracts (REs) with different ellagitannins to flavan-3-ols ratios might favorably affect the caecal fermentation processes and blood lipid profile in rats. Forty male Wistar rats were fed with a standard diet or its modification with two types of REs (E1 and E2) characterized by different ratios of ellagitannins to flavan-3-ols (7.7 and 3.1 for E1 and E2, respectively) and added to a diet at two dosages of polyphenolic compounds (0.15 and 0.30% of a diet; L and H treatments, respectively). Irrespective of polyphenols dietary level, both REs reduced the activity of bacterial β-glucuronidase, increased production of butyric acid in the caecum and reduced triacylglycerols in blood plasma. The E1 treatment at both dosages caused more effective reduction in the concentration of ammonia and elevated acetate level in the caecal digesta than E2. On the other hand, only the E2 treatment lowered value of the atherogenic index when compared with control group. When comparing dosages of REs, a higher one was more potent to reduce the activity of bacterial β-glucosidase, β-, α-galactosidase and lowered value of the HDL profile in plasma. To conclude, REs may favorably modulate the activity of the caecal microbiota and blood lipid profile in rats; however, the intensity of these effects may be related to the dosages of dietary polyphenols and to their profile, e.g., ellagitannins to flavan-3-ols ratio.

  15. Influence of Plasma Transferred Arc Process Parameters on Structure and Mechanical Properties of Wear Resistive NiCrBSi-WC/Co Coatings

    Directory of Open Access Journals (Sweden)

    Eitvydas GRUZDYS

    2011-07-01

    Full Text Available Self-fluxing NiCrBSi and related coatings received considerable interest due to their good wear as well as corrosion resistance at moderate and elevated temperatures. Hard tungsten carbide (WC particles can be included in NiCrBSi for further increase of the coating hardness and abrasive wear resistance. Flame spray technique is widely used for fabrication of NiCrBSi films. However, in such a case, subsequent remelting of the deposited coatings by flame, arc discharge or high power laser beam is necessary. In present study NiCrBSi-WC/Co coatings were formed using plasma transferred arc process. By adjusting plasma parameters, such as current, plasma gas flow, shielding gas flow, a number of coatings were formed on steel substrates. Structure of the coatings was investigated using X-ray diffractometry. Microstructure of cross-sectioned coatings was examined using scanning electron microscopy. Hardness of the coating was evaluated by means of the Vickers hardness tests. Wear tests were also performed on specimens to determine resistance to abrasive wear. Acquired results allowed estimating the influence of the deposition process parameters on structure and mechanical properties of the coatings.http://dx.doi.org/10.5755/j01.ms.17.2.482

  16. Processing Parameter Effects and Thermal Properties of Y2Si2O7 Nanostructured Environmental Barrier Coatings Synthesized by Solution Precursor Induction Plasma Spraying

    Science.gov (United States)

    Darthout, Émilien; Laduye, Guillaume; Gitzhofer, François

    2016-09-01

    The solution precursor plasma spray process, in which a solution of metal salts is axially injected into an induction thermal plasma, is suitable for deposition of nanostructured environmental barrier coatings. The effects of main processing parameters, namely the solution precursor concentration, spraying distance, reactor pressure, and atomization gas flow rate, have been analyzed using D-optimal design of experiments regarding the deposition rate and coating porosity responses. Among these four parameters, the solution precursor concentration had the greatest influent on the coating structure, followed by the spraying distance and reactor pressure, and finally the atomization gas flow rate with a small contribution. It is pointed out that the species that impact on the substrate are agglomerates of nanoparticles. The equivalent thermal conductivity of selected coatings was computed from experimental temperature evolution curves obtained by laser flash thermal diffusivity analysis, using two methods: a multilayer finite-element model with optimization, and a multilayer thermal diffusion model. The results of the two models agree, with coatings exhibiting low thermal conductivity between 0.7 and 1 W/(m K) at 800 °C.

  17. Processing Parameter Effects and Thermal Properties of Y2Si2O7 Nanostructured Environmental Barrier Coatings Synthesized by Solution Precursor Induction Plasma Spraying

    Science.gov (United States)

    Darthout, Émilien; Laduye, Guillaume; Gitzhofer, François

    2016-10-01

    The solution precursor plasma spray process, in which a solution of metal salts is axially injected into an induction thermal plasma, is suitable for deposition of nanostructured environmental barrier coatings. The effects of main processing parameters, namely the solution precursor concentration, spraying distance, reactor pressure, and atomization gas flow rate, have been analyzed using D-optimal design of experiments regarding the deposition rate and coating porosity responses. Among these four parameters, the solution precursor concentration had the greatest influent on the coating structure, followed by the spraying distance and reactor pressure, and finally the atomization gas flow rate with a small contribution. It is pointed out that the species that impact on the substrate are agglomerates of nanoparticles. The equivalent thermal conductivity of selected coatings was computed from experimental temperature evolution curves obtained by laser flash thermal diffusivity analysis, using two methods: a multilayer finite-element model with optimization, and a multilayer thermal diffusion model. The results of the two models agree, with coatings exhibiting low thermal conductivity between 0.7 and 1 W/(m K) at 800 °C.

  18. Plasma Processing of Materials

    Science.gov (United States)

    1985-02-22

    used in France. In this case, three ’ movable electrodes arranged about the central axis with a coaxial sheath gas are employed. Initially the...Demiocratic Republic plasma furnace. chrome -magnesite; the bottom section is lined with rammed chrome -magnesite refractory. Due to the high heat loads... sheath injector design, cathode tip shape, and degree of water cooling are important parameters in providing a stable, uncontaminating, long-lifetime

  19. Sensor for monitoring plasma parameters

    CERN Document Server

    Bolshakov, A A; Sharma, S P; Bol'shakov, Alexander A.; Cruden, Brett A.; Sharma, Surendra P.

    2004-01-01

    A spectrally tunable VCSEL (vertical cavity surface-emitting laser) was used as part of sensing hardware for measurements of the radial-integrated gas temperature inside an inductively coupled plasma reactor. The data were obtained by profiling the Doppler-broadened absorption of metastable Ar atoms at 763.51 nm in argon and argon/nitrogen plasmas (3, 45, and 90% N2 in Ar) at pressure 0.5-70 Pa and inductive power of 100 and 300 W. The results were compared to rotational temperature derived from the N2 emission at the (0,0) transition of the C - B system. The differences in integrated rotational and Doppler temperatures were attributed to non-uniform spatial distributions of both temperature and thermometric species (Ar* and N2*) that varied depending on conditions. A two-dimensional, two-temperature fluid plasma simulation was employed to explain these differences. This work should facilitate further development of a miniature sensor for non-intrusive acquisition of data (temperature and densities of multipl...

  20. Spark Plasma Sintering constrained process parameters of sintered silver paste for connection in power electronic modules: Microstructure, mechanical and thermal properties

    Energy Technology Data Exchange (ETDEWEB)

    Alayli, N. [Université Paris 13, Sorbonne Paris Cité, Laboratoire des Sciences des Procédés et des Matériaux, Centre National de la Recherche Scientifique, Unité Propre de Recherche 3407, 99 avenue Jean Baptiste Clément, F-93430 Villetaneuse (France); Université de Versailles-Saint-Quentin-en-Yvelines, Sorbonne Universités, Université Pierre et Marie Curie, Université Paris 06, Centre National de la Recherche Scientifique/INSU, Laboratoire Atmosphères Milieux Observations Spatiales-IPSL, Quartier des Garennes, 11 Boulevard d' Alembert, F-78280 Guyancourt (France); Schoenstein, F., E-mail: frederic.schoenstein@univ-paris13.fr [Université Paris 13, Sorbonne Paris Cité, Laboratoire des Sciences des Procédés et des Matériaux, Centre National de la Recherche Scientifique, Unité Propre de Recherche 3407, 99 avenue Jean Baptiste Clément, F-93430 Villetaneuse (France); Girard, A. [Office National d' Étude et de Recherches Aérospatiales, Laboratoire d' Étude des Microstructures, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 104, 29 avenue de la Division Leclerc, F-92322 Châtillon (France); and others

    2014-11-14

    Processing parameters of Spark Plasma Sintering (SPS) technique were constrained to process nano sized silver particles bound in a paste for interconnection in power electronic devices. A novel strategy combining debinding step and consolidation processes (SPS) in order to elaborate nano-structured silver bulk material is investigated. Optimum parameters were sought for industrial power electronics packaging from the microstructural and morphological properties of the sintered material. The latter was studied by Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD) to determine the density and the grain size of crystallites. Two types of samples, termed S1 (bulk) and S2 (multilayer) were elaborated and characterized. They are homogeneous with a low degree of porosity and a good adhesion to the substrate and the process parameters are compatible with industrial constraints. As the experimental results show, the mean crystallite size is between 60 nm and 790 nm with a density between 50% and 92% resulting in mechanical and thermal properties that are better than that of lead free solder. The best SPS sintering parameters, the applied pressure, the temperature and the processing time were determined as being 3 MPa, 300 °C and 1 min respectively when the desizing time of the preprocessing step was kept below 5 min at 150 °C. Using these processing parameters, acceptable for automotive packaging industry, a semi-conductor power chip was successfully connected to a metalized substrate by sintered silver with thermal and electrical properties better than those of current solders and with thermomechanical properties allowing absorption of thermoplastic stresses. - Highlights: • The sintered silver joints have nanometric structure. • The grain growth was controlled by the SPS sintering parameters. • New connection material improve thermal and electrical properties of current solders. • Interconnection's plastic strain can absorb thermo

  1. Effects of various power process parameters on deposition efficiency of plasma-sprayed Al2O3-40% wt.TiO2 coatings

    Science.gov (United States)

    Wang, Y. J.; Xu, J. Y.; Zhao, Q. H.; Wang, Y.; Gao, B.

    2017-06-01

    To investigate effects of various power process parameters on deposition efficiency, Al2O3-40% wt. TiO2 is selected as raw material to be coated on Q235 steel substrate by air plasma spraying. Different variables of spraying current and voltage are designed, whose spraying power is from 12.8 KW to 16.8 KW and increment step is 0.8 KW. Deposition thickness is proposed as a simple method to characterize the deposition efficiency of coatings. Analysis of variance is used to observe the difference between two adjacent groups. It is shown that deposition efficiency increases with the increase of spraying current; by and large, it firstly rises and then decreases with the increment of spraying voltage. However, the effects of increasing the latter are much stronger on deposition efficiency.

  2. Optimization of audio - ultrasonic plasma system parameters

    Science.gov (United States)

    Haleem, N. A.; Abdelrahman, M. M.; Ragheb, M. S.

    2016-10-01

    The present plasma is a special glow plasma type generated by an audio ultrasonic discharge voltage. A definite discharge frequency using a gas at a narrow band pressure creates and stabilizes this plasma type. The plasma cell is a self-extracted ion beam; it is featured with its high output intensity and its small size. The influence of the plasma column length on the output beam due to the variation of both the audio discharge frequency and the power applied to the plasma electrodes is investigated. In consequence, the aim of the present work is to put in evidence the parameters that influence the self-extracted collected ion beam and to optimize the conditions that enhance the collected ion beam. The experimental parameters studied are the nitrogen gas, the applied frequency from 10 to 100 kHz, the plasma length that varies from 8 to 14 cm, at a gas pressure of ≈ 0.25 Torr and finally the discharge power from 50 to 500 Watt. A sheet of polyethylene of 5 micrometer covers the collector electrode in order to confirm how much ions from the beam can go through the polymer and reach the collector. To diagnose the occurring events of the beam on the collector, the polymer used is analyzed by means of the FTIR and the XRF techniques. Optimization of the plasma cell parameters succeeded to enhance and to identify the parameters that influence the output ion beam and proved that its particles attaining the collector are multi-energetic.

  3. Avaliação da influência dos parâmetros de spray a plasma sobre a cristalinidade de recobrimentos de hidroxiapatita Effect of plasma spray process parameters on the crystallinity of hydroxyapatite coatings

    Directory of Open Access Journals (Sweden)

    S. N. da Silva

    1999-05-01

    Full Text Available Os parâmetros de spray a plasma influenciam na cristalinidade do recobrimento na medida em que determinadas condições de operação alteram a entalpia da tocha, produzindo variado grau de fusão das partículas do pó, além em de poder ainda causar modificações nas condições de resfriamento e solidificação. Neste trabalho, os efeitos dos principais parâmetros - corrente elétrica de ionização do plasma, proporção da mistura dos gases de reação e distância do bico da tocha (anodo até o substrato - sobre a cristalinidade de recobrimentos de hidroxiapatita foram avaliados. Os experimentos foram conduzidos utilizando o planejamento fatorial a três variáveis em dois níveis, com réplicas. O pó de hidroxiapatita utilizado foi da Calcitek-USA. O índice de cristalinidade dos recobrimentos nas diferentes condições foi determinado com base em método de análise quantitativa utilizando espectros de difração de raios X. O parâmetro de processo que mostrou ter maior efeito sobre a cristalinidade foi a distância tocha-substrato. O índice de cristalinidade medido para os recobrimentos produzidos variou de 20-68%. O tratamento térmico dos recobrimentos elevou o índice de cristalinidade para 99%.Plasma spraying process parameters greatly affect the coatings crystallinity since they can change the torch enthalpy, causing substantial melting of the particles and also affecting their cooling and solidification processes. In this work, the effect of the process parameters - current, proportion of primary/secondary gases and distance torch-substrate - on the crystallinity of hydroxyapatite coatings were evaluated. The experiments were carried out using a complete factorial design, with three parameters in two levels. The hydroxyapatite powder used was from Calcitek-USA. The crystallinity index was determined based on a quantitative procedure using the x-ray diffraction spectra. The process parameter which had the major effect on the

  4. Sensitivity of transient synchrotron radiation to tokamak plasma parameters

    Energy Technology Data Exchange (ETDEWEB)

    Fisch, N.J.; Kritz, A.H.

    1988-12-01

    Synchrotron radiation from a hot plasma can inform on certain plasma parameters. The dependence on plasma parameters is particularly sensitive for the transient radiation response to a brief, deliberate, perturbation of hot plasma electrons. We investigate how such a radiation response can be used to diagnose a variety of plasma parameters in a tokamak. 18 refs., 13 figs.

  5. Study on Performance Parameters of the Plasma Source for a Short-Conduction-Time Plasma Opening Switch

    Institute of Scientific and Technical Information of China (English)

    LUO Weixi; ZENG Zhengzhong; WANG Liangping; LEI Tianshi; HU Yixiang; HUANG Tao; SUN Tieping

    2012-01-01

    Plasma source performance parameters, including plasma ejection density and velocity, greatly affect the operation of a short-conduction-time plasma opening switch (POS). In this paper, the plasma source used in the POS of Qiangguang I generator is chosen as the study object. At first the POS working process is analyzed. The result shows that the opening performance of the POS can be improved by increasing the plasma ejection velocity and decreasing the plasma density. The influence of the cable plasma gun structure and number on the plasma ejection parameters is experimentally investigated with two charge collectors. Finally a semi-empirical model is proposed to describe the experimental phenomenon.

  6. Correlation between optical emission spectra and the process parameters of a 915 MHz microwave plasma CVD reactor used for depositing polycrystalline diamond coatings

    Indian Academy of Sciences (India)

    Awadesh Kumar Mallik; Sandip Bysakh; Someswar Dutta; Debabrata Basu

    2014-08-01

    In this paper, the hydrogen and hydrogen-methane mixed plasma have been generated inside a 33 cm diameter quartz bell jar with a low power (9 KW) and lower frequency 915 MHz microwave plasma chemical vapor deposition system. The reactor is being used for growing polycrystalline diamond (PCD) over large area (100 mm). The generated plasma is diagnosed by in situ optical emission spectroscopy method with wave length ranging from 200 to 900 nm. The effects of microwave power, chamber pressure and gas concentration on plasma characteristics have been studied in this work. Within the optical range, Balmer H, H, C2swan band and CH lines have been detected at the wavelengths of 655.95, 485.7, 515.82 and 430.17 nm, respectively. It has been observed that for hydrogen plasma, the amount of transition from hydrogen atom inner shell 3 to 2 (H) is almost constant with increasing microwave (MW) power (from 2000 to 2800 W) and pressure (from 15 to 30 Torr) initially, after that it increases with further increase of MW power and pressure, whereas, the transition from 4 to 2 (H) is slowly increased with increasing MW power and pressure. For hydrogen-methane plasma, intensities of C2 swan band, i.e., the transitions from D$^3\\Pi_\\text{g}$ to A$^3\\Pi_{\\mu}$ energy levels, are also increased with the increasing microwave power and reactor pressure. It has been observed that the radicals present in the plasma are affected by variation of different reactor parameters like pressure, MW power, CH4 concentration, etc.

  7. Atomic processes in optically thin plasmas

    Science.gov (United States)

    Kaastra, Jelle S.; Gu, Liyi; Mao, Junjie; Mehdipour, Missagh; Raassen, Ton; Urdampilleta, Igone

    2016-10-01

    The Universe contains a broad range of plasmas with quite different properties depending on distinct physical processes. In this contribution we give an overview of recent developments in modeling such plasmas with a focus on X-ray emission and absorption. Despite the fact that such plasmas have been investigated already for decades, and that overall there is a good understanding of the basic processes, there are still areas, where improvements have to be made that are important for the analysis of astrophysical plasmas. We present recent work on the update of atomic parameters in the codes that describe the emission from collisional plasmas, where older approximations are being replaced now by more accurate data. Further we discuss the development of models for photo-ionised plasmas in the context of outflows around supermassive black holes and models for charge transfer that are needed for analyzing the data from the upcoming ASTRO-H satellite.

  8. Advanced plasma diagnostics for plasma processing

    Science.gov (United States)

    Malyshev, Mikhail Victorovich

    1999-10-01

    A new, non-intrusive, non-perturbing diagnostic method was developed that can be broadly applied to low pressure, weakly ionized plasmas and glow discharges-trace rare gases optical emission spectroscopy (TRG-OES). The method is based on a comparison of intensities of atomic emission from trace amounts of inert gases (He, Ne, Ar, Kr, and Xe) that are added to the discharge to intensities calculated from the theoretical model. The model assumes a Maxwellian electron energy distribution function (EEDF), computes the population of emitting levels both from the ground state and the metastable states of rare gases, and from the best fit between theory and experiment determines electron temperature (Te). Subject to conditions, TRG-OES can also yield electron density or its upper or lower limit. From the comparison of the emission from levels excited predominantly by high energy electrons to that excited by low energy electrons, information about the EEDF can be obtained. The use of TRG-OES also allows a traditionally qualitative actinometry technique (determination of concentration of radical species in plasma through optical emission) to become a precise quantitative method by including Te and rare gases metastables effects. A combination of TRG-OES, advanced actinometry, and Langmuir probe measurements was applied to several different plasma reactors and regimes of operation. Te measurements and experiments to correct excitation cross section were conducted in a laboratory helical resonator. Two chamber configuration of a commercial (Lam Research) metal etcher were studied to determine the effects of plasma parameters on plasma-induced damage. Two different methods (RF inductive coupling and ultra-high frequency coupling) for generating a plasma in a prototype reactor were also studied. Pulsed plasmas, a potential candidate to eliminate the plasma-induced damage to microelectronics devices that occurs in manufacturing due to differential charging of the wafer, have

  9. Effect of pulsed current micro plasma arc welding process parameters on fusion zone grain size and ultimate tensile strength of Inconel 625 sheets

    Institute of Scientific and Technical Information of China (English)

    Kondapalli Siva Prasad; Chalamalasetti Srinivasa Rao; Damera Nageswara Rao

    2012-01-01

    The paper focuses on developing mathematical models to predict grain size and ultimate tensile strength of pulsed current micro plasma arc welded Inconel 625 nickel alloy.Four factors,five levels,central composite rotatable design matrix is used to optimize the number of experiments.The mathematical models have been developed by response surface method.The adequacy of the models is checked by analysis of variance technique.By using the developed mathematical models,grain size and ultimate tensile strength of the joints can be predicted with 99%0 confidence level.Contour plots are drawn to study the interaction effect of pulsed current micro plasma arc welding parameters on fusion zone grain size and ultimate tensile strength of Inconel 625 weld ioints.

  10. A plasma process monitor/control system

    Energy Technology Data Exchange (ETDEWEB)

    Stevenson, J.O.; Ward, P.P.; Smith, M.L. [Sandia National Labs., Albuquerque, NM (United States); Markle, R.J. [Advanced Micro Devices, Inc., Austin, TX (United States)

    1997-08-01

    Sandia National Laboratories has developed a system to monitor plasma processes for control of industrial applications. The system is designed to act as a fully automated, sand-alone process monitor during printed wiring board and semiconductor production runs. The monitor routinely performs data collection, analysis, process identification, and error detection/correction without the need for human intervention. The monitor can also be used in research mode to allow process engineers to gather additional information about plasma processes. The plasma monitor can perform real-time control of support systems known to influence plasma behavior. The monitor can also signal personnel to modify plasma parameters when the system is operating outside of desired specifications and requires human assistance. A notification protocol can be selected for conditions detected in the plasma process. The Plasma Process Monitor/Control System consists of a computer running software developed by Sandia National Laboratories, a commercially available spectrophotometer equipped with a charge-coupled device camera, an input/output device, and a fiber optic cable.

  11. Investigation of plasma parameters in an active screen cage-pulsed dc plasma used for plasma nitriding

    Science.gov (United States)

    Naeem, M.; Khattak, Z. I.; Zaka-ul-Islam, M.; Shabir, S.; Khan, A. W.; Zakaullah, M.

    2014-11-01

    Active screen cage-pulsed dc plasmas are widely used in the material processing applications such as plasma nitriding, carburizing and nitrocarburizing. Specifically for plasma nitriding applications, a H2-N2 mixture is used. In this article, a study of the electron number density (ne), atomic nitrogen density ([N]), electron temperature ? and the excitation temperature ? is reported in the presence of an active screen cage-pulsed dc plasma. The ne and ? are determined here by a triple Langmuir probe, while [N] and ? are estimated by optical emission spectroscopy (OES). The two temperatures and their ratio ? are compared for different input parameters (such as applied power, gas pressure and H2 percentage). This study is useful in active screen cage plasma nitriding applications where only few plasma diagnostic measurements have been reported.

  12. Variation of plasma parameters in a modified mode of plasma production in a double plasma device

    Indian Academy of Sciences (India)

    A Phukan; M K Mishra; B K Saikia; M Chakraborty

    2010-03-01

    A modified mode of plasma production in a double plasma device is presented and plasma parameters are controlled in this configuration. Here plasma is produced by applying a discharge voltage between the hot filaments in the source (cathode) and the target magnetic cage (anode) of the device. In this configuration, the hot electron emitting filaments are present only in the source and the magnetic cage of this is kept at a negative bias such that due to the repulsion of the cage bias, the primary electrons can go to the grounded target and produce plasma there. The plasma parameters can be controlled by varying the voltages applied to the source magnetic cage and the separation grid of the device.

  13. Saturn Plasma Sources and Associated Transport Processes

    Science.gov (United States)

    Blanc, M.; Andrews, D. J.; Coates, A. J.; Hamilton, D. C.; Jackman, C. M.; Jia, X.; Kotova, A.; Morooka, M.; Smith, H. T.; Westlake, J. H.

    2015-10-01

    This article reviews the different sources of plasma for Saturn's magnetosphere, as they are known essentially from the scientific results of the Cassini-Huygens mission to Saturn and Titan. At low and medium energies, the main plasma source is the H2O cloud produced by the "geyser" activity of the small satellite Enceladus. Impact ionization of this cloud occurs to produce on the order of 100 kg/s of fresh plasma, a source which dominates all the other ones: Titan (which produces much less plasma than anticipated before the Cassini mission), the rings, the solar wind (a poorly known source due to the lack of quantitative knowledge of the degree of coupling between the solar wind and Saturn's magnetosphere), and the ionosphere. At higher energies, energetic particles are produced by energy diffusion and acceleration of lower energy plasma produced by the interchange instabilities induced by the rapid rotation of Saturn, and possibly, for the highest energy range, by contributions from the CRAND process acting inside Saturn's magnetosphere. Discussion of the transport and acceleration processes acting on these plasma sources shows the importance of rotation-induced radial transport and energization of the plasma, and also shows how much the unexpected planetary modulation of essentially all plasma parameters of Saturn's magnetosphere remains an unexplained mystery.

  14. Plasma processing of superconducting radio frequency cavities

    Science.gov (United States)

    Upadhyay, Janardan

    The development of plasma processing technology of superconducting radio frequency (SRF) cavities not only provides a chemical free and less expensive processing method, but also opens up the possibility for controlled modification of the inner surfaces of the cavity for better superconducting properties. The research was focused on the transition of plasma etching from two dimensional flat surfaces to inner surfaces of three dimensional (3D) structures. The results could be applicable to a variety of inner surfaces of 3D structures other than SRF cavities. Understanding the Ar/Cl2 plasma etching mechanism is crucial for achieving the desired modification of Nb SRF cavities. In the process of developing plasma etching technology, an apparatus was built and a method was developed to plasma etch a single cell Pill Box cavity. The plasma characterization was done with the help of optical emission spectroscopy. The Nb etch rate at various points of this cavity was measured before processing the SRF cavity. Cylindrical ring-type samples of Nb placed on the inner surface of the outer wall were used to measure the dependence of the process parameters on plasma etching. The measured etch rate dependence on the pressure, rf power, dc bias, temperature, Cl2 concentration and diameter of the inner electrode was determined. The etch rate mechanism was studied by varying the temperature of the outer wall, the dc bias on the inner electrode and gas conditions. In a coaxial plasma reactor, uniform plasma etching along the cylindrical structure is a challenging task due to depletion of the active radicals along the gas flow direction. The dependence of etch rate uniformity along the cylindrical axis was determined as a function of process parameters. The formation of dc self-biases due to surface area asymmetry in this type of plasma and its variation on the pressure, rf power and gas composition was measured. Enhancing the surface area of the inner electrode to reduce the

  15. Programmable physical parameter optimization for particle plasma simulations

    Science.gov (United States)

    Ragan-Kelley, Benjamin; Verboncoeur, John; Lin, Ming-Chieh

    2012-10-01

    We have developed a scheme for interactive and programmable optimization of physical parameters for plasma simulations. The simulation code Object-Oriented Plasma Device 1-D (OOPD1) has been adapted to a Python interface, allowing sophisticated user or program interaction with simulations, and detailed numerical analysis via numpy. Because the analysis/diagnostic interface is the same as the input mechanism (the Python programming language), it is straightforward to optimize simulation parameters based on analysis of previous runs and automate the optimization process using a user-determined scheme and criteria. An example use case of the Child-Langmuir space charge limit in bipolar flow is demonstrated, where the beam current is iterated upon by measuring the relationship of the measured current and the injected current.

  16. A secondary fuel removal process: plasma processing

    Energy Technology Data Exchange (ETDEWEB)

    Min, J. Y.; Kim, Y. S. [Hanyang Univ., Seoul (Korea, Republic of); Bae, K. K.; Yang, M. S. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1997-07-01

    Plasma etching process of UO{sub 2} by using fluorine containing gas plasma is studied as a secondary fuel removal process for DUPIC (Direct Use of PWR spent fuel Into Candu) process which is taken into consideration for potential future fuel cycle in Korea. CF{sub 4}/O{sub 2} gas mixture is chosen for reactant gas and the etching rates of UO{sub 2} by the gas plasma are investigated as functions of CF{sub 4}/O{sub 2} ratio, plasma power, substrate temperature, and plasma gas pressure. It is found that the optimum CF{sub 4}/O{sub 2} ratio is around 4:1 at all temperatures up to 400 deg C and the etching rate increases with increasing r.f. power and substrate temperature. Under 150W r.f. power the etching rate reaches 1100 monolayers/min at 400 deg C, which is equivalent to about 0.5mm/min. (author).

  17. Plasma Arc Cutting Dimensional Accuracy Optimization employing the Parameter Design approach

    Directory of Open Access Journals (Sweden)

    Kechagias John

    2017-01-01

    Full Text Available Plasma Arc Cutting (PAC is a thermal manufacturing process used for metal plates cutting. This work experimentally investigates the influence of process parameters onto the dimensional accuracy performance of the plasma arc cutting process. The cutting parameters studied were cutting speed (mm/min, torch standoff distance (mm, and arc voltage (volts. Linear dimensions of a rectangular workpiece were measured after PAC cutting following the full factorial design experimental approach. For each one of the three process parameters, three parameter levels were used. Analysis of means (ANOM and analysis of variances (ANOVA were performed in order for the effect of each parameter on the leaner dimensional accuracy to be assessed.

  18. Plasma detachment with molecular processes in divertor plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Ohno, N.; Ezumi, N.; Nishijima, D.; Takamura, S. [Dept. of Energy Engineering and Science, Graduate School of Engineering, Nagoya Univ., Nagoya, Aichi (Japan); Krasheninnikov, S.I.; Pigarov, A.Yu. [MIT Plasma Science and Fusion Center, Cambridge, MA (United States)

    2000-01-01

    Molecular processes in detached recombining plasmas are briefly reviewed. Several reactions with vibrationally excited hydrogen molecule related to recombination processes are described. Experimental evidence of molecular activated recombination observed in a linear divertor plasma simulator is also shown. (author)

  19. Status and challenges in electrical diagnostics of processing plasmas

    DEFF Research Database (Denmark)

    Stamate, Eugen

    2014-01-01

    Dry processing based on reactive plasmas was the main driven force for micro- and recently nano-electronic industry. Once with the increasing in plasma complexity new diagnostics methods have been developed to ensure a proper process control during etching, thin film deposition, ion implantation...... or other steps in device fabrication. This work reviews some of the unconventional methods developed in the last two decays to measure the parameters of reactive plasmas including, the test function method, thermal probes, and plasma-sheath-lens probes. The negative ion detection and surface contamination...... in plasmas with a high degree of contamination are also addressed. (C) 2014 Elsevier B.V. All rights reserved....

  20. Taguchi Analysis on the Effect of Process Parameters on Densification During Spark Plasma Sintering of HfB2-20SiC (Preprint)

    Science.gov (United States)

    2011-11-01

    pressing and spark plasma sintering. J Alloys Compd 2007; 428:197–05. 2. Van Wie D.M., Drewry Jr. D.G., King D.E., Hudson C.M. The hypersonic environment...spark plasma sintering of HfB2/SiC and HfB2/HfC/SiC composite powders obtained by self-propagating high-temperature synthesis. J Alloys Compd 2009...2008; 91:10:3448-50. 9. Carmen M Carney. Oxidation resistance of hafnium diboride—silicon carbide from 1400 to 2000 °C. J Mater Sci 2009; 44:20:5673-81

  1. Parameters of atmospheric plasmas produced by electrosurgical devices

    Science.gov (United States)

    Keidar, Michael; Shashurin, Alexey; Canady, Jerome

    2013-10-01

    Electrosurgical systems are extensively utilized in general surgery, surgical oncology, plastic and reconstructive surgery etc. In this work we study plasma parameters created by electrosurgical system SS-200E/Argon 2 of US Medical Innovations. The maximal length of the discharge plasma column at which the discharge can be sustained was determined as function of discharge power and argon flow rate. Electrical parameters including discharge current and voltage were measured. Recently proposed Rayleigh microwave scattering method for temporally resolved density measurements of small-size atmospheric plasmas was utilized. Simultaneously, evolution of plasma column was observed using intensified charge-coupled device (ICCD) camera.

  2. Numerical Simulation of Basic Parameters in Plasma Spray

    Institute of Scientific and Technical Information of China (English)

    范群波; 王鲁; 王富耻

    2004-01-01

    On the basis of energy balance in the plasma gas, a new, simplified but effective mathematical model is developed to predict the temperature, velocity and ionization degrees of different species at the torch exit, which can be directly calculated just by inputting the general spraying parameters, such as current, voltage, flow rates of gases, etc. Based on this method, the effects of plasma current and the flow rate of Ar on the basic parameters at the torch exit are discussed. The results show that the temperature, velocity and ionization degrees of gas species will increase with increasing the plasma current; while increasing Ar flow rate can increase the velocity at the exit but decrease the temperature and ionization degrees of plasma species. The method would be helpful to predict the temperature and velocity fields in a plasma jet in future, and direct the practical plasma spray operations.

  3. Plasma parameters controlled by remote electron shower in a double plasma device

    Science.gov (United States)

    Mishra, M. K.; Phukan, A.

    2012-07-01

    The principal feature of this experiment is the electron showers consisting of three tungsten wires embedded by the plasma, which are heated up consequently emitting electrons inside the diffused plasma to control the plasma parameters in the discharge section of a double plasma device. These cold electrons emitted by the heated filament are free from maintenance of discharge which is sustained in the source section. The target plasma, where electrons are injected is produced as a result of diffusion from the source section. It is found that, plasma density and plasma potential can be effectively controlled in this way.

  4. A study on plasma parameters in Ar/SF6 inductively coupled plasma

    Science.gov (United States)

    Oh, Seung-Ju; Lee, Hyo-Chang; Chung, Chin-Wook

    2017-01-01

    Sulfur hexafluoride (SF6) gas or Ar/SF6 mixing gas is widely used in plasma processes. However, there are a little experimental studies with various external parameters such as gas pressure and mixing ratio. In this work, a study of the plasma parameters by changing the gas mixing ratio was done in an Ar/SF6 inductively coupled plasma from the measurement of the electron energy distribution function. At a low gas pressure, as the mixing ratio of SF6 gas increased at a fixed inductively coupled plasma (ICP) power, the electron density decreased and the electron temperature increased, while they were not changed drastically. At a high gas pressure, a remarkable increase in the electron temperature was observed with the decrease in the electron density. These variations are due to the electron loss reactions such as the electron attachment. It was also found that at a fixed ICP power, the negative ion creation with the diluted SF6 gas can change the discharge mode transition from an inductive mode to a capacitive mode at the high gas pressure. The electron attachment reactions remove the low energy electrons and change the mean electron energy towards higher energies with diluting SF6 gas at high pressure. The measured results were compared with the simplified global model, and the global model is in relatively good agreement with the measured plasma parameters except for the result in the case of the large portion of SF6 gas at the high pressure and the capacitive mode, which causes strong negative ion formation by the electron attachment reactions.

  5. Study of parameters of a facility generating compressive plasma flows

    Science.gov (United States)

    Leyvi, A. Ya

    2017-05-01

    The prosperity of plasma technologies stimulates making of a facility generating compressive plasma flows at the South Ural State University. The facility is a compact-geometry magnetoplasma compressor with the following parameters: stored energy up to 15 kJ, voltage of a bank from 3 to 5 kV; nitrogen, air, and other gases can serve as its operating gas. The investigation of parameters of the facility showed the following parameters of compressive plasma flows: impulse duration of up to 120 μs, discharge current of 50-120 kA, speed of plasma flow of 15-30 km/s. By contrast to the available facilities, the parameters of the developed facility can be adjusted in a wide range of voltage from 2 kV to 10 kV, its design permits generating CPF in horizontal and vertical positions.

  6. Collisionless expansion of pulsed radio frequency plasmas. II. Parameter study

    Science.gov (United States)

    Schröder, T.; Grulke, O.; Klinger, T.; Boswell, R. W.; Charles, C.

    2016-01-01

    The plasma parameter dependencies of the dynamics during the expansion of plasma are studied with the use of a versatile particle-in-cell simulation tailored to a plasma expansion experiment [Schröder et al., J. Phys. D: Appl. Phys. 47, 055207 (2014); Schröder et al., Phys. Plasmas 23, 013511 (2016)]. The plasma expansion into a low-density ambient plasma features a propagating ion front that is preceding a density plateau. It has been shown that the front formation is entangled with a wave-breaking mechanism, i.e., an ion collapse [Sack and Schamel, Plasma Phys. Controlled Fusion 27, 717 (1985); Sack and Schamel, Phys. Lett. A 110, 206 (1985)], and the launch of an ion burst [Schröder et al., Phys. Plasmas 23, 013511 (2016)]. The systematic parameter study presented in this paper focuses on the influence on this mechanism its effect on the maximum velocity of the ion front and burst. It is shown that, apart from the well known dependency of the front propagation on the ion sound velocity, it also depends sensitively on the density ratio between main and ambient plasma density. The maximum ion velocity depends further on the initial potential gradient, being mostly influenced by the plasma density ratio in the source and expansion regions. The results of the study are compared with independent numerical studies.

  7. INTRODUCTION: Nonequilibrium Processes in Plasmas

    Science.gov (United States)

    Petrović, Zoran; Marić, Dragana; Malović, Gordana

    2009-07-01

    This book aims to give a cross section from a wide range of phenomena that, to different degrees, fall under the heading of non-equilibrium phenomenology. The selection is, of course, biased by the interests of the members of the scientific committee and of the FP6 Project 026328 IPB-CNP Reinforcing Experimental Centre for Non-equilibrium Studies with Application in Nano-technologies, Etching of Integrated Circuits and Environmental Research. Some of the papers included here are texts based on selected lectures presented at the Second International Workshop on Non-equilibrium Processes in Plasmas and Environmental Science. However, this volume is not just the proceedings of that conference as it contains a number of papers from authors that did not attend the conference. The goal was to put together a volume that would cover the interests of the project and support further work. It is published in the Institute of Physics journal Journal of Physics: Conference Series to ensure a wide accessibility of the articles. The texts presented here range from in-depth reviews of the current status and past achievements to progress reports of currently developed experimental devices and recently obtained still unpublished results. All papers have been refereed twice, first when speakers were selected based on their reputation and recently published results, and second after the paper was submitted both by the editorial board and individual assigned referees according to the standards of the conference and of the journal. Nevertheless, we still leave the responsibility (and honours) for the contents of the papers to the authors. The papers in this book are review articles that give a summary of the already published work or present the work in progress that will be published in full at a later date (or both). In the introduction to the first volume, in order to show how far reaching, ubiquitous and important non-equilibrium phenomena are, we claimed that ever since the early

  8. Study on plasma parameters and dust charging in an electrostatically plugged multicusp plasma device

    Science.gov (United States)

    Kakati, B.; Kausik, S. S.; Saikia, B. K.; Bandyopadhyay, M.

    2011-06-01

    The effect of the electrostatic confinement potential on the charging of dust grains and its relationship with the plasma parameters has been studied in an electrostatically plugged multicusp dusty plasma device. Electrostatic plugging is implemented by biasing the electrically isolated magnetic multicusp channel walls. The experimental results show that voltage applied to the channel walls can be a controlling parameter for dust charging.

  9. Effect of plasma processing reactor circuitry on plasma characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Rauf, S.; Kushner, M.J. [Univ. of Illinois, Urbana, IL (United States). Dept. of Electrical and Computer Engineering

    1997-12-31

    It is well known that external circuitry greatly influences the performance of plasma processing reactors. Simulation of external circuits difficult since the time in which the external circuit attains the steady-state is several orders of magnitude longer than typical plasma simulation time scales. In this paper, the authors present a technique to simulate the external circuit concurrently with the plasma, and implement it into the Hybrid Plasma Equipment Model (HPEM). The resulting model is used to investigate the influence of external circuitry on plasma behavior.

  10. Atomic and molecular processes in fusion plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Janev, R.K. [International Atomic Energy Agency, Vienna (Austria)

    1997-01-01

    The role of atomic and molecular processes in achieving and maintaining the conditions for thermonuclear burn in a magnetically confined fusion plasma is described. Emphasis is given to the energy balance and power and particle exhaust issues. The most important atomic and molecular processes which affect the radiation losses and impurity transport in the core plasma, the neutral particle transport in the plasma edge and the radiative cooling of divertor plasmas are discussed in greater detail. (author)

  11. Roughness parameter selection for novel manufacturing processes.

    Science.gov (United States)

    Ham, M; Powers, B M

    2014-01-01

    This work proposes a method of roughness parameter (RP) selection for novel manufacturing processes or processes where little knowledge exists about which RPs are important. The method selects a single parameter to represent a group of highly correlated parameters. Single point incremental forming (SPIF) is used as the case study for the manufacturing process. This methodology was successful in reducing the number of RPs investigated from 18 to 8 in the case study. © Wiley Periodicals, Inc.

  12. Langmuir probe Diagnostic for local parameter measurement in Magnetized Plasma using LabVIEW

    Directory of Open Access Journals (Sweden)

    Bijal Vara

    2014-03-01

    Full Text Available In recent years, plasma technology is used by Semiconductor, thin film industries for deposit layers, etching process and surface modification. So it is necessary to understanding internal plasma parameter. Langmuir probe is one of the simplest techniques which is used to measure wide range of plasma parameter like plasma potential, floating potential, electron temperature, electron energy distribution function (EEDF etc. Langmuir current voltage characteristic is obtained by varying bias voltage of the probe. LabVIEW is most powerful Microsoft window compatible software which is used to immediate data acquisition and analysis. In this paper describes analysis of Langmuir data using LabVIEW software which automatically measure I-V Plasma probe Characteristics and obtain EEDF of plasma.

  13. Study on the ignition process of a segmented plasma torch

    Science.gov (United States)

    Cao, Xiuquan; Yu, Deping; Xiang, Yong; Li, Chao; Jiang, Hui; Yao, Jin

    2017-07-01

    Direct current plasma torches have been applied to generate unique sources of thermal energy in many industrial applications. Nevertheless, the successful ignition of a plasma torch is the key process to generate the unique source (plasma jet). However, there has been little study on the underlying mechanism of this key process. A thorough understanding of the ignition process of a plasma torch will be helpful for optimizing the design of the plasma torch structure and selection of the ignition parameters to prolong the service life of the ignition module. Thus, in this paper, the ignition process of a segmented plasma torch (SPT) is theoretically and experimentally modeled and analyzed. Corresponding electrical models of different stages of the ignition process are set up and used to derive the electrical parameters, e.g. the variations of the arc voltage and arc current between the cathode and anode. In addition, the experiments with different ignition parameters on a home-made SPT have been conducted. At the same time, the variations of the arc voltage and arc current have been measured, and used to verify the ones derived in theory and to determine the optimal ignition parameters for a particular SPT.

  14. Plasma Processes : Arc root dynamics in high power plasma torches – Evidence of chaotic behavior

    Indian Academy of Sciences (India)

    A K Das

    2000-11-01

    Although plasma torches have been commercially available for about 50 years, areas such as plasma gun design, process efficiency, reproducibility, plasma stability, torch lives etc. have remained mostly unattended. Recent torch developments have been focusing on the basic understanding of the plasma column and its dynamics inside the plasma torch, the interaction of plasma jet and the powders, the interaction of the plasma jet with surroundings and the impingement of the jet on the substrate. Two of the major causes of erratic and poor performance of a variety of thermal plasma processes are currently identified as the fluctuations arising out of the arc root movement on the electrodes inside the plasma torch and the fluid dynamic instabilities arising out of entrainment of the air into the plasma jet. This paper reviews the current state of understanding of these fluctuations as well as the dynamics of arc root movement in plasma torches. The work done at the author’s laboratory on studying the fluctuations in arc voltage, arc current, acoustic emissions and optical emissions are also presented. These fluctuations are observed to be chaotic and interrelated. Real time monitoring and controlling the arc instabilities through chaos characterization parameters can greatly contribute to the understanding of electrode erosion as well as improvement of plasma torch lifetime.

  15. Development of Expert Controller for Plasma Spraying Process

    Institute of Scientific and Technical Information of China (English)

    LIChun-xu; CHENKe-xuan; LIHe-qi; LIDe-wu

    2004-01-01

    Aiming at the plasma spraying process control, the control system model is developed on the basis of analyzing control parameters and coating properties and their correlation, and the corresponding control method and regulations are also given. With the developed expert controller for plasma spraying process, stable spraying can be realized using ordinary spraying powder and the coating of compaction, homogeneity and high bonding strength can be obtained.

  16. Plasma chemistry study of PLAD processes

    Energy Technology Data Exchange (ETDEWEB)

    Qin Shu; Brumfield, Kyle; Liu, Lequn Jennifer; Hu, Yongjun Jeff; McTeer, Allen; Hsu, Wei Hui; Wang Maoying [Nanya Technology Inc., Santa Clara, CA 95054 (United States); Micron Technology Inc., Boise, ID 83707 (United States)

    2012-11-06

    Plasma doping (PLAD) shows very different impurity profiles compared to the conventional beam-line-based ion implantations due to its non-mass separation property and plasma environment. There is no simulation for PLAD process so far due to a lack of a dopant profile model. Several factors determine impurity profiles of PLAD process. The most significant factors are: plasma chemistry and deposition/etching characteristics of multi-ion species plasmas. In this paper, we present plasma chemistry and deposition/etching characteristics of PLAD processes versus co-gas dilutions. Four dopant plasmas including B{sub 2}H{sub 6}, BF{sub 3}, AsH{sub 3}, and PH{sub 3}, and two non-dopant plasmas including CH{sub 4} and GeH{sub 4} are studied and demonstrated.

  17. Influence of direct current plasma magnetron sputtering parameters on the material characteristics of polycrystalline copper films

    Energy Technology Data Exchange (ETDEWEB)

    Chan, K.-Y. [Thin Film Laboratory, Faculty of Engineering, Multimedia University, Jalan Multimedia, 63100 Cyberjaya, Selangor (Malaysia)], E-mail: k.y.chan@fz-juelich.de; Luo, P.-Q.; Zhou, Z.-B. [Department of Physics, Shanghai Jiao Tong University, 800 Dongchuan Road, 200240 Shanghai (China); Tou, T.-Y.; Teo, B.-S. [Thin Film Laboratory, Faculty of Engineering, Multimedia University, Jalan Multimedia, 63100 Cyberjaya, Selangor (Malaysia)

    2009-03-01

    Physical vapor processes using glow plasma discharge are widely employed in microelectronic industry. In particular magnetron sputtering is a major technique employed for the coating of thin films. This paper addresses the influence of direct current (DC) plasma magnetron sputtering parameters on the material characteristics of polycrystalline copper (Cu) thin films coated on silicon substrates. The influence of the sputtering parameters including DC plasma power and argon working gas pressure on the electrical and structural properties of the thin Cu films was investigated by means of surface profilometer, four-point probe and atomic force microscopy.

  18. Synthesis of Single Wall Carbon Nanotubes by Plasma Arc: Role of Plasma Parameters

    Science.gov (United States)

    Farhart, Samir; Scott, Carl D.

    2000-01-01

    Single wall carbon nanotubes (SWNT) are porous objects on the molecular scale and have a low density, which gives them potential applications as adsorbent for molecular hydrogen. Their H2 absorption capacity published in the literature varies from 4 to 10% by mass according to the purity of the materials and storage conditions. Optimization of production methods of SWNTs should permit improving these new materials for storage of hydrogen. In this article, we show the potential of using SWNTs in hydrogen storage. In particular, we pose problems associated with synthesis, purification, and opening up of the nanotubes. We present an electric arc process currently used at laboratory scale to produce single wall carbon nanotubes. We discuss, in particular, operating conditions that permit growth of nanotubes and some plasma parameters that assure control of the material. Analysis of the process is carried out with the aid of local measurements of temperature and scanning and transmission electron microscopy of the materials.

  19. Atmospheric Pressure Plasma Process And Applications

    Energy Technology Data Exchange (ETDEWEB)

    Peter C. Kong; Myrtle

    2006-09-01

    This paper provides a general discussion of atmospheric-pressure plasma generation, processes, and applications. There are two distinct categories of atmospheric-pressure plasmas: thermal and nonthermal. Thermal atmospheric-pressure plasmas include those produced in high intensity arcs, plasma torches, or in high intensity, high frequency discharges. Although nonthermal plasmas are at room temperatures, they are extremely effective in producing activated species, e.g., free radicals and excited state atoms. Thus, both thermal and nonthermal atmosphericpressure plasmas are finding applications in a wide variety of industrial processes, e.g. waste destruction, material recovery, extractive metallurgy, powder synthesis, and energy conversion. A brief discussion of recent plasma technology research and development activities at the Idaho National Laboratory is included.

  20. Atmospheric pressure plasmas for aerosols processes in materials and environment

    Science.gov (United States)

    Borra, J. P.; Jidenko, N.; Bourgeois, E.

    2009-08-01

    The paper highlights applications of some atmospheric pressure plasmas (dc-corona, streamer and spark and ac-Dielectric Barrier Discharges) to aerosol processes for Materials and Environment (filtration, diagnostics). The production of vapor i.e. condensable gaseous species, leads to nano-sized particles by physical and chemical routes of nucleation in these AP plasmas: (i) when dc streamer and spark filamentary discharges as well as ac filamentary dielectric barrier discharges interact with metal or dielectric surfaces, and (ii) when discharges induce reactions with gaseous precursors in volume. It is shown how composition, size and structure of primary nano-particles are related to plasma parameters (energy, number per unit surface and time and thermal gradients). Then the growth by coagulation controls the final size of agglomerates versus plasma parameters and transit time in and after the plasma. Charging and electro-thermal collection are depicted to account for the related potential applications of controlled kinematics of charged aerosol.

  1. Cold plasma processing to improve food safety

    Science.gov (United States)

    Cold plasma is an antimicrobial process being developed for application as a food processing technology. This novel intervention is the subject of an expanding research effort by groups around the world. A variety of devices can be used to generate cold plasma and apply it to the food commodity bein...

  2. State and parameter estimation in bio processes

    Energy Technology Data Exchange (ETDEWEB)

    Maher, M.; Roux, G.; Dahhou, B. [Centre National de la Recherche Scientifique (CNRS), 31 - Toulouse (France)]|[Institut National des Sciences Appliquees (INSA), 31 - Toulouse (France)

    1994-12-31

    A major difficulty in monitoring and control of bio-processes is the lack of reliable and simple sensors for following the evolution of the main state variables and parameters such as biomass, substrate, product, growth rate, etc... In this article, an adaptive estimation algorithm is proposed to recover the state and parameters in bio-processes. This estimator utilizes the physical process model and the reference model approach. Experimentations concerning estimation of biomass and product concentrations and specific growth rate, during batch, fed-batch and continuous fermentation processes are presented. The results show the performance of this adaptive estimation approach. (authors) 12 refs.

  3. Plasma Processing of Large Curved Surfaces for SRF Cavity Modification

    CERN Document Server

    Upadhyay, J; Popović, S; Valente-Feliciano, A -M; Phillips, L; Vušković, L

    2014-01-01

    Plasma based surface modification of niobium is a promising alternative to wet etching of superconducting radio frequency (SRF) cavities. The development of the technology based on Cl2/Ar plasma etching has to address several crucial parameters which influence the etching rate and surface roughness, and eventually, determine cavity performance. This includes dependence of the process on the frequency of the RF generator, gas pressure, power level, the driven (inner) electrode configuration, and the chlorine concentration in the gas mixture during plasma processing. To demonstrate surface layer removal in the asymmetric non-planar geometry, we are using a simple cylindrical cavity with 8 ports symmetrically distributed over the cylinder. The ports are used for diagnosing the plasma parameters and as holders for the samples to be etched. The etching rate is highly correlated with the shape of the inner electrode, radio-frequency (RF) circuit elements, chlorine concentration in the Cl2/Ar gas mixtures, residence...

  4. Mirror-field confined compact plasma source using permanent magnet for plasma processings

    Science.gov (United States)

    Goto, Tetsuya; Sato, Kei-ichiro; Yabuta, Yuki; Sugawa, Shigetoshi

    2016-12-01

    A mirror-field confined compact electron cyclotron resonance (ECR) plasma source using permanent magnets was developed, aiming for the realization of high-quality plasma processings where high-density reactive species are supplied to a substrate with minimizing the ion bombardment damages. The ECR position was located between a microwave transmissive window and a quartz limiter, and plasmas were transported from the ECR position to a midplane of the magnetic mirror field through the quartz limiter. Thus, a radius of core plasma could be determined by the limiter, which was 15 mm in this study. Plasma parameters were investigated by the Langmuir probe measurement. High-density plasma larger than 1011 cm-3 could be produced by applying 5.85-GHz microwave power of 10 W or more. For the outside region of the core plasma where a wafer for plasma processings will be set at, the ion current density was decreased dramatically with distance from the core plasma and became smaller by approximately two orders of magnitude that in the core plasma region for the radial position of 40 mm, suggesting the realization of reduction in ion bombardment damages.

  5. Mirror-field confined compact plasma source using permanent magnet for plasma processings.

    Science.gov (United States)

    Goto, Tetsuya; Sato, Kei-Ichiro; Yabuta, Yuki; Sugawa, Shigetoshi

    2016-12-01

    A mirror-field confined compact electron cyclotron resonance (ECR) plasma source using permanent magnets was developed, aiming for the realization of high-quality plasma processings where high-density reactive species are supplied to a substrate with minimizing the ion bombardment damages. The ECR position was located between a microwave transmissive window and a quartz limiter, and plasmas were transported from the ECR position to a midplane of the magnetic mirror field through the quartz limiter. Thus, a radius of core plasma could be determined by the limiter, which was 15 mm in this study. Plasma parameters were investigated by the Langmuir probe measurement. High-density plasma larger than 10(11) cm(-3) could be produced by applying 5.85-GHz microwave power of 10 W or more. For the outside region of the core plasma where a wafer for plasma processings will be set at, the ion current density was decreased dramatically with distance from the core plasma and became smaller by approximately two orders of magnitude that in the core plasma region for the radial position of 40 mm, suggesting the realization of reduction in ion bombardment damages.

  6. Status and challenges in electrical diagnostics of processing plasmas

    DEFF Research Database (Denmark)

    Stamate, Eugen

    Reactive plasmas produced in oxygen, nitrogen, hydrogen and other complex gas mixture are used for various applications including thin films, etching, ion implantation, ashing, particles growth, oxidation and other surface functionalization processes. Most of the reactive gases are also...... the possibility to control and use these plasmas for processing. Development of reactive plasma sources for both applications and basic science is rather challenging and some of these efforts will be presented in direct correlation with diagnostic approaches....... electronegative so that, the role of negative ions cannot be neglected. The continuous decrease of the features size in micro- and nanoelectronic industry requires a precise control of plasma parameters including the negative ions. Despite of a good progress in plasma diagnostics, yet more is to be done...

  7. Antireflection coatings on plastics deposited by plasma polymerization process

    Indian Academy of Sciences (India)

    K M K Srivatsa; M Bera; A Basu; T K Bhattacharya

    2008-08-01

    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 industry, plastic lenses are rapidly displacing glass lenses due to several advantageous features. However, the deposition of ARCs on plastic lenses is a challenging task, because the plastic surface needs treatment for adhesion improvement and surface hardening before depositing the ARC. This surface treatment is usually done in a multi-stage process—exposure to energetic radiations, followed by deposition of a carbonyl hard coating by spin or dip coating processes, UV curing, etc. However, this treatment can also be done by plasma processes. Moreover, the plasma polymerization process allows deposition of optical films at room temperature, essential for plastics. The energetic ions in plasma processes provide similar effects as in ion assisted physical deposition processes to produce hard coatings, without requiring sophisticated ion sources. The plasma polymerization process is more economical than ion-assisted physical vapour deposition processes as regards equipment and source materials and is more cost-effective, enabling the surface treatment and deposition of the ARC in the same deposition system in a single run by varying the system parameters at each step. Since published results of the plasma polymerization processes developed abroad are rather sketchy and the techniques are mostly veiled in commercial secrecy, innovative and indigenous plasma-based techniques have been developed in this work for depositing the complete ARCs on plastic substrates.

  8. Surface studies of plasma processed Nb samples

    Energy Technology Data Exchange (ETDEWEB)

    Tyagi, Puneet V. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Doleans, Marc [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Hannah, Brian S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Afanador, Ralph [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Stewart, Stephen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Mammosser, John [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Howell, Matthew P [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Saunders, Jeffrey W [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Degraff, Brian D [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Kim, Sang-Ho [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)

    2015-01-01

    Contaminants present at top surface of superconducting radio frequency (SRF) cavities can act as field emitters and restrict the cavity accelerating gradient. A room temperature in-situ plasma processing technology for SRF cavities aiming to clean hydrocarbons from inner surface of cavities has been recently developed at the Spallation Neutron Source (SNS). Surface studies of the plasma-processed Nb samples by Secondary ion mass spectrometry (SIMS) and Scanning Kelvin Probe (SKP) showed that the NeO2 plasma processing is very effective to remove carbonaceous contaminants from top surface and improves the surface work function by 0.5 to 1.0 eV.

  9. Space plasma physics: I - Stationary processes

    Science.gov (United States)

    Hasegawa, Akira; Sato, Tetsuya

    1989-01-01

    The physics of stationary processes in space plasmas is examined theoretically in an introduction intended for graduate students. The approach involves the extensive use of numerical simulations. Chapters are devoted to fundamental principles, small-amplitude waves, and the stationary solar plasma system; typical measurement data and simulation results are presented graphically.

  10. Developments in Plasma Processes for Extractive Metallurgy

    Science.gov (United States)

    Gauvin, W. H.; Drouet, M. G.; Munz, R. J.

    1987-12-01

    With the recent availability of commercial plasma-generating devices capable of reliable performance at powers as high as 30 MW, the applications of plasma technology in high-temperature extractive metallurgy are rapidly increasing. Some of the more promising process developments are reviewed in this paper, as are newer reactor designs.

  11. Effect of gasification parameter on coal gasification in thermal plasma

    Energy Technology Data Exchange (ETDEWEB)

    Shen, S.; Pang, X.; Bao, W.; Lo, Y.; Zhu, S. [Taiyuan University of Technology, Taiyuan (China)

    2004-12-01

    The influence of several parameters such as the power input of plasma jet, vapor and air input etc on gas composition and carbon conversion from coal gasification in an air-steam plasma jet was studied. The main gaseous products are H{sub 2}, CO, CO{sub 2}, CH{sub 2}4 and tar was discovered. Results show that the concentration of H{sub 2}, CO and carbon conversion increases, and the concentration of CO{sub 2} significantly decreases, when the power input of plasma jet is raised. The concentration of H{sub 2} increases when the vapor flux is increased, but excessive steam can decrease carbon conversion. The carbon conversion is enhanced by decreasing feed rate. The air flux should be reduced to improve the quality of coal gas in a certain range. The carbon conversion of Datong coal can exceed 95% at appropriate condition. 18 refs., 4 figs., 2 tabs.

  12. Effect of Substrate Potential on Plasma Parameters of Magnetic Multicusp Plasma Source

    Science.gov (United States)

    Ueda, Yoshio; Goto, Masahiro

    1998-06-01

    The effect of substrate potential on plasmas produced in a magnetic multicusp plasma source has been studied experimentally. Plasma parameters such as electron temperature and plasma potential are estimated from electron energy distribution function numerically calculated from probe current-voltage characteristics. For a substrate potential of -150 V with respect to the source chamber, which is much lower than substrate floating potentials, the plasma parameters are not affected by the application of the potential. However, for the case where the substrate is shorted with the source chamber, the high energy component of electrons significantly decreases in comparison with the floating case leading to the reduction of electron temperature. In this case, plasma potential is positive with respect to the substrate to suppress electron loss but its absolute value is only of the order of electron temperature in eV, which is much lower than the potential between the plasma and the substrate in the floating case. This discharge mode could be advantageous in significantly reducing the ion impact energy to the substrate plate.

  13. Prediction of plasma simulation data with the Gaussian process method

    Energy Technology Data Exchange (ETDEWEB)

    Preuss, R.; Toussaint, U. von, E-mail: udo.v.toussaint@ipp.mpg.de [Max-Planck-Institute for Plasma Physics, EURATOM Association, 85748 Garching (Germany)

    2014-12-05

    The simulation of plasma-wall interactions of fusion plasmas is extremely costly in computer power and time - the running time for a single parameter setting is easily in the order of weeks or months. We propose to exploit the already gathered results in order to predict the outcome for parametric studies within the high dimensional parameter space. For this we utilize Gaussian processes within the Bayesian framework and perform validation with one and two dimensional test cases from which we learn how to assess the outcome. Finally, the newly implemented method is applied to simulated data from the scrape-off layer of a fusion plasma. Uncertainties of the predictions are provided which point the way to parameter settings of further (expensive) simulations.

  14. Fundamental Processes in Plasmas. Final report

    Energy Technology Data Exchange (ETDEWEB)

    O' Neil, Thomas M.; Driscoll, C. Fred

    2009-11-30

    This research focuses on fundamental processes in plasmas, and emphasizes problems for which precise experimental tests of theory can be obtained. Experiments are performed on non-neutral plasmas, utilizing three electron traps and one ion trap with a broad range of operating regimes and diagnostics. Theory is focused on fundamental plasma and fluid processes underlying collisional transport and fluid turbulence, using both analytic techniques and medium-scale numerical simulations. The simplicity of these systems allows a depth of understanding and a precision of comparison between theory and experiment which is rarely possible for neutral plasmas in complex geometry. The recent work has focused on three areas in basic plasma physics. First, experiments and theory have probed fundamental characteristics of plasma waves: from the low-amplitude thermal regime, to inviscid damping and fluid echoes, to cold fluid waves in cryogenic ion plasmas. Second, the wide-ranging effects of dissipative separatrices have been studied experimentally and theoretically, finding novel wave damping and coupling effects and important plasma transport effects. Finally, correlated systems have been investigated experimentally and theoretically: UCSD experients have now measured the Salpeter correlation enhancement, and theory work has characterized the 'guiding center atoms of antihydrogen created at CERN.

  15. Impact of plasma parameter on self-organization of electron temperature gradient driven turbulence

    Science.gov (United States)

    Kawai, C.; Idomura, Y.; Maeyama, S.; Ogawa, Y.

    2017-04-01

    Self-organization in the slab electron temperature gradient driven (ETG) turbulence is investigated based on gyrokinetic simulations and the Hasegawa-Mima (HM) equation. The scale and the anisotropy of self-organized turbulent structures vary depending on the Rhines scale and the characteristic scale given by the adiabatic response term in the HM equation. The former is determined by competition between the linear wave dispersion and the nonlinear turbulent cascade, while the latter is given as the scale, at which the turbulent cascade is impeded. These scales are controlled by plasma parameters such as the density and temperature gradient, and the temperature ratio of ion to electron. It is found that depending on the plasma parameters, the ETG turbulence shows either isotropic turbulence or zonal flows, which give significantly different transport levels. Although the modulational instability excites zonal modes regardless of the plasma parameters, the final turbulent structure is determined by the self-organization process.

  16. Hydrogen Plasma Processing of Iron Ore

    Science.gov (United States)

    Sabat, Kali Charan; Murphy, Anthony B.

    2017-06-01

    Iron is currently produced by carbothermic reduction of oxide ores. This is a multiple-stage process that requires large-scale equipment and high capital investment, and produces large amounts of CO2. An alternative to carbothermic reduction is reduction using a hydrogen plasma, which comprises vibrationally excited molecular, atomic, and ionic states of hydrogen, all of which can reduce iron oxides, even at low temperatures. Besides the thermodynamic and kinetic advantages of a hydrogen plasma, the byproduct of the reaction is water, which does not pose any environmental problems. A review of the theory and practice of iron ore reduction using a hydrogen plasma is presented. The thermodynamic and kinetic aspects are considered, with molecular, atomic and ionic hydrogen considered separately. The importance of vibrationally excited hydrogen molecules in overcoming the activation energy barriers, and in transferring energy to the iron oxide, is emphasized. Both thermal and nonthermal plasmas are considered. The thermophysical properties of hydrogen and argon-hydrogen plasmas are discussed, and their influence on the constriction and flow in the of arc plasmas is considered. The published R&D on hydrogen plasma reduction of iron oxide is reviewed, with both the reduction of molten iron ore and in-flight reduction of iron ore particles being considered. Finally, the technical and economic feasibility of the process are discussed. It is shown that hydrogen plasma processing requires less energy than carbothermic reduction, mainly because pelletization, sintering, and cokemaking are not required. Moreover, the formation of the greenhouse gas CO2 as a byproduct is avoided. In-flight reduction has the potential for a throughput at least equivalent to the blast furnace process. It is concluded that hydrogen plasma reduction of iron ore is a potentially attractive alternative to standard methods.

  17. Hydrogen Plasma Processing of Iron Ore

    Science.gov (United States)

    Sabat, Kali Charan; Murphy, Anthony B.

    2017-03-01

    Iron is currently produced by carbothermic reduction of oxide ores. This is a multiple-stage process that requires large-scale equipment and high capital investment, and produces large amounts of CO2. An alternative to carbothermic reduction is reduction using a hydrogen plasma, which comprises vibrationally excited molecular, atomic, and ionic states of hydrogen, all of which can reduce iron oxides, even at low temperatures. Besides the thermodynamic and kinetic advantages of a hydrogen plasma, the byproduct of the reaction is water, which does not pose any environmental problems. A review of the theory and practice of iron ore reduction using a hydrogen plasma is presented. The thermodynamic and kinetic aspects are considered, with molecular, atomic and ionic hydrogen considered separately. The importance of vibrationally excited hydrogen molecules in overcoming the activation energy barriers, and in transferring energy to the iron oxide, is emphasized. Both thermal and nonthermal plasmas are considered. The thermophysical properties of hydrogen and argon-hydrogen plasmas are discussed, and their influence on the constriction and flow in the of arc plasmas is considered. The published R&D on hydrogen plasma reduction of iron oxide is reviewed, with both the reduction of molten iron ore and in-flight reduction of iron ore particles being considered. Finally, the technical and economic feasibility of the process are discussed. It is shown that hydrogen plasma processing requires less energy than carbothermic reduction, mainly because pelletization, sintering, and cokemaking are not required. Moreover, the formation of the greenhouse gas CO2 as a byproduct is avoided. In-flight reduction has the potential for a throughput at least equivalent to the blast furnace process. It is concluded that hydrogen plasma reduction of iron ore is a potentially attractive alternative to standard methods.

  18. Pulsed Plasma Methods in Materials Processing

    Science.gov (United States)

    Rej, D. J.

    1996-05-01

    Plasmas are routinely used to synthesize advanced materials, because of their ability to produce reactant species that enable a wide variety of chemical reactions. For example, in microelectronics manufacturing, plasmas are used to etch, clean, ash photoresist, implant, deposit, polymerize, and metalize. The use of pulsed power may extend the utility of plasma processing. Pulsed devices such as coaxial plasma guns, cathodic arcs, pseudosparks have been employed to synthesize materials ranging from novel steel alloys and high-temperature superconductors to diamond coatings. In this talk, we will highlight plasma immersion ion implantation and deposition, methods that improve conventional steady-state chemical and physical vapor deposition techniques. Pulsed power enables energetic ion bombardment before plasma deposition to promote better film adhesion through the formation of a graded interface. Ion bombardment during deposition reduces residual stress in the deposited film, thereby enabling formation of thick layers. Also, pulsed plasma sources have advantages over steady-state devices in that they conserve electrical power and can produce high-density, fully-dissociated plasmas. As an example, we will review recent experiments on the formation of adherent diamond-like carbon films deposited onto relatively large batches of automotive components.

  19. Plasma characterization studies for materials processing

    Energy Technology Data Exchange (ETDEWEB)

    Pfender, E.; Heberlein, J. [Univ. of Minnesota, Minneapolis, MN (United States)

    1995-12-31

    New applications for plasma processing of materials require a more detailed understanding of the fundamental processes occurring in the processing reactors. We have developed reactors offering specific advantages for materials processing, and we are using modeling and diagnostic techniques for the characterization of these reactors. The emphasis is in part set by the interest shown by industry pursuing specific plasma processing applications. In this paper we report on the modeling of radio frequency plasma reactors for use in materials synthesis, and on the characterization of the high rate diamond deposition process using liquid precursors. In the radio frequency plasma torch model, the influence of specific design changes such as the location of the excitation coil on the enthalpy flow distribution is investigated for oxygen and air as plasma gases. The diamond deposition with liquid precursors has identified the efficient mass transport in form of liquid droplets into the boundary layer as responsible for high growth, and the chemical properties of the liquid for the film morphology.

  20. Cluster processes in gases and plasmas

    CERN Document Server

    Smirnov, Boris M

    2009-01-01

    Boris M. Smirnov received his Ph.D. in physics from Leningrad State University in 1968. After working in different research positions, he finally accepted a post as head of one of the divisions of the Institute for High Temperatures at the Russian Academy of Sciences in Moscow in 1986. Professor Smirnov is the author and co-author of approximately 50 books as well as 400 research articles in plasma physics, atomic physics, and atomic clusters. He is Vice Chairman of the National Council for Low Temperature Plasma and Chairman ofa Section on Elementary Processes in Plasma. Professor Smirnov`s r

  1. Ultrasonic Plasma Spray--A New Plasma Spray Process

    Institute of Scientific and Technical Information of China (English)

    LU Zhi-qing; ZHANG Hua-tang; WEN Xiong-wei; LI Lu-ming

    2004-01-01

    The method of arc- ultrasonic is introduced into plasma spray process. The process of spray ZrO2-NiCoCr AlY thermal barrier coatings (TBCs) using air plasma spray (APS) process is studied. A exciting source which can be adjusted from audio frequency to several hundred thousand Hertz is designed successfully. The ultrasonic exciting source is coupled with conventional DC spraying power supply. A few ultrasonic frequencies are selected in the testing. Several parts of the coatings with the coupling arc- ultrasonic are compared with the coatings without it. The results show: with 50 kHz and 80 kHz ultrasound, the coating qualities are improved, whereas 30 kHz has an opposite effect.

  2. Study on spatial distribution of plasma parameters in a magnetized inductively coupled plasma

    Energy Technology Data Exchange (ETDEWEB)

    Cheong, Hee-Woon; Lee, Woohyun; Kim, Ji-Won; Whang, Ki-Woong, E-mail: kwhang@snu.ac.kr [Plasma Laboratory, Inter-University Semiconductor Research Center, Department of Electrical and Computer Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of); Kim, Hyuk [Samsung Electronics Co., Banwol-dong, Hwaseong 445-701 (Korea, Republic of); Park, Wanjae [Tokyo Electron Miyagi Ltd., Taiwa-cho, Kurokawa-gun, Miyagi 981-3629 (Japan)

    2015-07-15

    Spatial distributions of various plasma parameters such as plasma density, electron temperature, and radical density in an inductively coupled plasma (ICP) and a magnetized inductively coupled plasma (M-ICP) were investigated and compared. Electron temperature in between the rf window and the substrate holder of M-ICP was higher than that of ICP, whereas the one just above the substrate holder of M-ICP was similar to that of ICP when a weak (<8 G) magnetic field was employed. As a result, radical densities in M-ICP were higher than those in ICP and the etch rate of oxide in M-ICP was faster than that in ICP without severe electron charging in 90 nm high aspect ratio contact hole etch.

  3. Atmospheric plasma processes for environmental applications

    OpenAIRE

    Shapoval, Volodymyr

    2012-01-01

    Plasma chemistry is a rapidly growing field which covers applications ranging from technological processing of materials, including biological tissues, to environmental remediation and energy production. The so called atmospheric plasma, produced by electric corona or dielectric barrier discharges in a gas at atmospheric pressure, is particularly attractive for the low costs and ease of operation and maintenance involved. The high concentrations of energetic and chemically active species (e.g...

  4. Atmospheric plasma processes for environmental applications

    OpenAIRE

    Shapoval, Volodymyr

    2012-01-01

    Plasma chemistry is a rapidly growing field which covers applications ranging from technological processing of materials, including biological tissues, to environmental remediation and energy production. The so called atmospheric plasma, produced by electric corona or dielectric barrier discharges in a gas at atmospheric pressure, is particularly attractive for the low costs and ease of operation and maintenance involved. The high concentrations of energetic and chemically active species (e.g...

  5. Analysis and Optimization of Central Processing Unit Process Parameters

    Science.gov (United States)

    Kaja Bantha Navas, R.; Venkata Chaitana Vignan, Budi; Durganadh, Margani; Rama Krishna, Chunduri

    2017-05-01

    The rapid growth of computer has made processing more data capable, which increase the heat dissipation. Hence the system unit CPU must be cooled against operating temperature. This paper presents a novel approach for the optimization of operating parameters on Central Processing Unit with single response based on response graph method. These methods have a series of steps from of proposed approach which are capable of decreasing uncertainty caused by engineering judgment in the Taguchi method. Orthogonal Array value was taken from ANSYS report. The method shows a good convergence with the experimental and the optimum process parameters.

  6. Modeling Approach and Analysis of the Structural Parameters of an Inductively Coupled Plasma Etcher Based on a Regression Orthogonal Design

    Institute of Scientific and Technical Information of China (English)

    CHENG Jia; ZHU Yu; JI Linhong

    2012-01-01

    The geometry of an inductively coupled plasma (ICP) etcher is usually considered to be an important factor for determining both plasma and process uniformity over a large wafer. During the past few decades, these parameters were determined by the "trial and error" method, resulting in wastes of time and funds. In this paper, a new approach of regression orthogonal design with plasma simulation experiments is proposed to investigate the sensitivity of the structural parameters on the uniformity of plasma characteristics. The tool for simulating plasma is CFD-ACE+, which is commercial multi-physical modeling software that has been proven to be accurate for plasma simulation. The simulated experimental results are analyzed to get a regression equation on three structural parameters. Through this equation, engineers can compute the uniformity of the electron number density rapidly without modeling by CFD-ACE+. An optimization performed at the end produces good results.

  7. The expansion of a plasma into a vacuum - Basic phenomena and processes and applications to space plasma physics

    Science.gov (United States)

    Wright, K. H., Jr.; Stone, N. H.; Samir, U.

    1983-01-01

    In this review attention is called to basic phenomena and physical processes involved in the expansion of a plasma into a vacuum, or the expansion of a plasma into a more tenuous plasma, in particular the fact that upon the expansion, ions are accelerated and reach energies well above their thermal energy. Also, in the process of the expansion a rarefaction wave propagates into the ambient plasma, an ion front moves into the expansion volume, and discontinuities in plasma parameters occur. The physical processes which cause the above phenomena are discussed, and their possible application is suggested for the case of the distribution of ions and electrons (hence plasma potential and electric fields) in the wake region behind artificial and natural obstacles moving supersonically in a rarefied space plasma. To illustrate this, some in situ results are reexamined. Directions for future work in this area via the utilization of the Space Shuttle and laboratory work are also mentioned.

  8. Space plasma physics stationary processes

    CERN Document Server

    Hasegawa, Akira

    1989-01-01

    During the 30 years of space exploration, important discoveries in the near-earth environment such as the Van Allen belts, the plasmapause, the magnetotail and the bow shock, to name a few, have been made. Coupling between the solar wind and the magnetosphere and energy transfer processes between them are being identified. Space physics is clearly approaching a new era, where the emphasis is being shifted from discoveries to understanding. One way of identifying the new direction may be found in the recent contribution of atmospheric science and oceanography to the development of fluid dynamics. Hydrodynamics is a branch of classical physics in which important discoveries have been made in the era of Rayleigh, Taylor, Kelvin and Helmholtz. However, recent progress in global measurements using man-made satellites and in large scale computer simulations carried out by scientists in the fields of atmospheric science and oceanography have created new activities in hydrodynamics and produced important new discover...

  9. Signal processing methods for MFE plasma diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Candy, J.V.; Casper, T.; Kane, R.

    1985-02-01

    The application of various signal processing methods to extract energy storage information from plasma diamagnetism sensors occurring during physics experiments on the Tandom Mirror Experiment-Upgrade (TMX-U) is discussed. We show how these processing techniques can be used to decrease the uncertainty in the corresponding sensor measurements. The algorithms suggested are implemented using SIG, an interactive signal processing package developed at LLNL.

  10. Effects of process parameters on hydrothermal carbonization

    Science.gov (United States)

    Uddin, Md. Helal

    In recent years there has been increased research activity in renewable energy, especially upgrading widely available lignicellulosic biomass, in a bid to counter the increasing environmental concerns related with the use of fossil fuels. Hydrothermal carbonization (HTC), also known as wet torrefaction or hot water pretreatment, is a process for pretreatment of diverse lignocellulosic biomass feedstocks, where biomass is treated under subcritical water conditions in short contact time to produce high-value products. The products of this process are: a solid mass characterized as biochar/biocoal/biocarbon, which is homogeneous, energy dense, and hydrophobic; a liquid stream composed of five and six carbon sugars, various organic acids, and 5-HMF; and a gaseous stream, mainly CO2. A number of process parameters are considered important for the extensive application of the HTC process. Primarily, reaction temperature determines the characteristics of the products. In the solid product, the oxygen carbon ratio decreases with increasing reaction temperature and as a result, HTC biochar has the similar characteristics to low rank coal. However, liquid and gaseous stream compositions are largely correlated with the residence time. Biomass particle size can also limit the reaction kinetics due to the mass transfer effect. Recycling of process water can help to minimize the utility consumption and reduce the waste treatment cost as a result of less environmental impact. Loblolly pine was treated in hot compressed water at 200 °C, 230 °C, and 260 °C with 5:1 water:biomass mass ratio to investigate the effects of process parameters on HTC. The solid product were characterized by their mass yields, higher heating values (HHV), and equilibrium moisture content (EMC), while the liquid were characterized by their total organic carbon content and pH value.

  11. Nonthermal Radiation Processes in Interplanetary Plasmas

    Science.gov (United States)

    Chian, A. C. L.

    1990-11-01

    RESUMEN. En la interacci6n de haces de electrones energeticos con plasmas interplanetarios, se excitan ondas intensas de Langmuir debido a inestabilidad del haz de plasma. Las ondas Langmuir a su vez interaccio nan con fluctuaciones de densidad de baja frecuencia para producir radiaciones. Si la longitud de las ondas de Langmujr exceden las condicio nes del umbral, se puede efectuar la conversi5n de modo no lineal a on- das electromagneticas a traves de inestabilidades parametricas. As se puede excitar en un plasma inestabilidades parametricas electromagneticas impulsadas por ondas intensas de Langmuir: (1) inestabilidades de decaimiento/fusi5n electromagnetica impulsadas por una bomba de Lang- muir que viaja; (2) inestabilidades dobles electromagneticas de decai- miento/fusi5n impulsadas por dos bombas de Langrnuir directamente opues- tas; y (3) inestabilidades de dos corrientes oscilatorias electromagne- ticas impulsadas por dos bombas de Langmuir de corrientes contrarias. Se concluye que las inestabilidades parametricas electromagneticas in- ducidas por las ondas de Langmuir son las fuentes posibles de radiacio- nes no termicas en plasmas interplanetarios. ABSTRACT: Nonthermal radio emissions near the local electron plasma frequency have been detected in various regions of interplanetary plasmas: solar wind, upstream of planetary bow shock, and heliopause. Energetic electron beams accelerated by solar flares, planetary bow shocks, and the terminal shock of heliosphere provide the energy source for these radio emissions. Thus, it is expected that similar nonthermal radiation processes may be responsible for the generation of these radio emissions. As energetic electron beams interact with interplanetary plasmas, intense Langmuir waves are excited due to a beam-plasma instability. The Langmuir waves then interact with low-frequency density fluctuations to produce radiations near the local electron plasma frequency. If Langmuir waves are of sufficiently large

  12. General collision branching processes with two parameters

    Institute of Scientific and Technical Information of China (English)

    CHEN AnYue; LI JunPing

    2009-01-01

    A new class of branching models, the general collision branching processes with two parameters, is considered in this paper. For such models, it is necessary to evaluate the absorbing probabilities and mean extinction times for both absorbing states. Regularity and uniqueness criteria are firstly established. Explicit expressions are then obtained for the extinction probability vector, the mean extinction times and the conditional mean extinction times. The explosion behavior of these models is investigated and an explicit expression for mean explosion time is established. The mean global holding time is also obtained. It is revealed that these properties are substantially different between the super-explosive and sub-explosive cases.

  13. Research of Plasma Spraying Process on Aluminum-Magnesium Alloy

    Directory of Open Access Journals (Sweden)

    Patricija Kavaliauskaitė

    2016-04-01

    Full Text Available The article examines plasma sprayed 95Ni-5Al coatings on alu-minum-magnesium (Mg ≈ 2,6‒3,6 % alloy substrate. Alumi-num-magnesium samples prior spraying were prepared with mechanical treatment (blasting with Al2O3. 95Ni-5Al coatings on aluminum-magnesium alloys were sprayed with different parameters of process and coating‘s thickness, porosity, micro-hardness and microstructure were evaluated. Also numerical simulations in electric and magnetic phenomena of plasma spray-ing were carried out.

  14. Effect of Plasma Nitriding Parameters on the Wear Resistance of Alloy Inconel 718

    Science.gov (United States)

    Kovací, Halim; Ghahramanzadeh ASL, Hojjat; Albayrak, Çigdem; Alsaran, Akgün; Çelik, Ayhan

    2016-11-01

    The effect of the temperature and duration of plasma nitriding on the microstructure and friction and wear parameters of Inconel 718 nickel alloy is investigated. The process of plasma nitriding is conducted in a nitrogen-hydrogen gaseous mixture at a temperature of 400, 500 and 600°C for 1 and 4 h. The modulus of elasticity of the nitrided layer, the micro- and nanohardness, the surface roughness, the friction factor and the wear resistance of the alloy are determined prior to and after the nitriding. The optimum nitriding regime providing the best tribological characteristics is determined.

  15. Evolution of plasma parameters in a He - N2/Ar magnetic pole enhanced inductive plasma source

    Science.gov (United States)

    Younus, Maria; Rehman, N. U.; Shafiq, M.; Zakaullah, M.; Abrar, M.

    2016-02-01

    A magnetic pole enhanced inductively coupled H e - N2/A r plasma is studied at low pressure, to monitor the effects of helium mixing on plasma parameters like electron number density (ne) , electron temperature (Te) , plasma potential (Vp ) , and electron energy probability functions (EEPFs). An RF compensated Langmuir probe is employed to measure these plasma parameters. It is noted that electron number density increases with increasing RF power and helium concentration in the mixture, while it decreases with increase in filling gas pressure. On the other hand, electron temperature shows an increasing trend with helium concentration in the mixture. At low RF powers and low helium concentration in the mixture, EEPFs show a "bi-Maxwellian" distribution with pressure. While at RF powers greater than 50 W and higher helium concentration in the mixture, EEPFs evolve into "Maxwellian" distribution. The variation of skin depth with RF power and helium concentration in the mixture, and its relation with EEPF are also studied. The effect of helium concentrations on the temperatures of two electron groups ( Tb u l k and Tt a i l ) in the "bi-Maxwellian" EEPFs is also observed. The temperature of low energy electron group ( Tb u l k) shows significant increase with helium addition, while the temperature of tail electrons ( Tt a i l) increases smoothly as compared to ( Tb u l k).

  16. Versatile particle collection concept for correlation of particle growth and discharge parameters in dusty plasmas

    Science.gov (United States)

    Hinz, A. M.; von Wahl, E.; Faupel, F.; Strunskus, T.; Kersten, H.

    2015-02-01

    The feasibility of collecting nanoparticles from a dusty plasma by means of the neutral drag force is investigated. The nanoparticles are formed in a capacitively coupled asymmetric discharge running in an Ar/C2H2—mixture at a frequency of 13.56 MHz and an RF-power of 9 W. By opening a gate valve between the plasma reactor and a vacuum chamber at a lower pressure at any desired point of the growth cycle of the dust particles a neutral gas flux is induced that drags the particles out of the plasma onto a substrate. By changing the parameters of the collection process, e.g. the substrate positioning or the substrate temperature, the efficiency of the collection process can be adjusted. Information about the particle size distributions is obtained by performing ex situ SEM measurements. As the collection process creates a time stamp in the in situ recorded control parameters, e.g. the self-bias voltage or the process gas pressure, a direct and precise correlation between the control parameters and the particle size distribution is obtained.

  17. Methods for characterising microphysical processes in plasmas

    CERN Document Server

    de Wit, T Dudok; Furno, I; Sorriso-Valvo, L; Zimbardo, G

    2013-01-01

    Advanced spectral and statistical data analysis techniques have greatly contributed to shaping our understanding of microphysical processes in plasmas. We review some of the main techniques that allow for characterising fluctuation phenomena in geospace and in laboratory plasma observations. Special emphasis is given to the commonalities between different disciplines, which have witnessed the development of similar tools, often with differing terminologies. The review is phrased in terms of few important concepts: self-similarity, deviation from self-similarity (i.e. intermittency and coherent structures), wave-turbulence, and anomalous transport.

  18. Analysis of Physics Processes in the AC Plasma Torch Discharge under High Pressure

    Science.gov (United States)

    Safronov, A. A.; Vasilieva, O. B.; Dudnik, J. D.; E Kuznetsov, V.; Kuchina, J. A.; Shiryaev, V. N.; Pavlov, A. V.

    2017-04-01

    The paper is devoted to investigation of electrophysical processes in the electric discharge generated by a three-phase AC plasma torch when using a high pressure inert working gas. AC plasma torch design with end electrodes intended for work on inert gases at pressures up to 81 bar is studied. Current-voltage characteristics for different gas flow rates and pressures are presented. Physical processes characteristics of the arising voltage ripples which depend on various working parameters of the plasma torch have been investigated. Arc burning processes in the electric discharge chamber of the three-phase AC plasma torch at various working parameters were photographed.

  19. The effect of plasma operating parameters on analyte signals in inductively coupled plasma-mass spectrometry

    Science.gov (United States)

    Horlick, G.; Tan, S. H.; Vaughan, M. A.; Rose, C. A.

    Utilizing the SCIEX ICP-MS an extensive study of the effects that plasma operating parameters have on analyte ion signals in ICP-MS has been carried out. Parameters studied included aerosol flow rate (nebulizer pressure), auxiliary flow rate, power and sampling depth (sampling position from the load coil). The two key parameters are aerosol flow rate (nebulizer pressure) and power. Elements can be grouped into characteristic behaviour patterns based on the overall dependence of their ion count signal on these two parameters. The nebulizer pressure-power behavior patterns allow a sensible selection of compromise operating conditions and significantly clarify single parameter observations which often indicate confusing trends in behavior. In addition to characterizing analyte ion signals the parameter behavior plots have also been used to study oxide species and plus two ions in ICP-MS. While aerosol flow rate and power appear to be the key ICP parameters in ICP-MS, ion signals are dependent on sampling depth and auxiliary flow rate and some data are also presented illustrating the signal dependence on these two parameters.

  20. Plasma Processes : Microwave plasma deposition of diamond like carbon coatings

    Indian Academy of Sciences (India)

    D S Patil; K Ramachandran; N Venkatramani; M Pandey; R D'Cunha

    2000-11-01

    The promising applications of the microwave plasmas have been appearing in the fields of chemical processes and semiconductor manufacturing. Applications include surface deposition of all types including diamond/diamond like carbon (DLC) coatings, etching of semiconductors, promotion of organic reactions, etching of polymers to improve bonding of the other materials etc. With a 2.45 GHz, 700 W, microwave induced plasma chemical vapor deposition (CVD) system set up in our laboratory we have deposited diamond like carbon coatings. The microwave plasma generation was effected using a wave guide single mode applicator. We have deposited DLC coatings on the substrates like stainless steel, Cu–Be, Cu and Si. The deposited coatings have been characterized by FTIR, Raman spectroscopy and ellipsometric techniques. The results show that we have achieved depositing ∼ 95% sp3 bonded carbon in the films. The films are uniform with golden yellow color. The films are found to be excellent insulators. The ellipsometric measurements of optical constant on silicon substrates indicate that the films are transparent above 900 nm.

  1. Plasma Processing of Lunar and Planetary Materials

    Science.gov (United States)

    Currier, R.; Blacic, J.

    2000-01-01

    Space exploration and colonization must include oxygen for propulsion and life support, as well as, structural materials for construction. To the extent possible, these should be derived from locally available planetary resources. We propose an extractive metallurgy and oxygen recovery process well-suited for resource utilization in space. Locally available minerals are placed in a radio frequency-generated hydrogen plasma. This is accomplished using a fluidized bed contacting device. Electromagnetic energy is coupled to the hydrogen gas forming a non-equilibrium plasma. The plasma produces the ideal reducing agent - atomic hydrogen - in direct and intimate contact with the solid particles. When using oxide minerals as a feed, atomic hydrogen extracts oxygen from the matrix through the formation of water. The water is subsequently split into oxygen and hydrogen (the hydrogen is then recycled back to the plasma reactor). The processed solids could then be refined to produce structural materials. A conceptual process flow diagram, which requires an initial charge of hydrogen, is given.

  2. Microwave plasma torch for processing hydrocarbon gases

    Directory of Open Access Journals (Sweden)

    Alex G. Zherlitsyn

    2016-03-01

    Full Text Available We designed and developed an ultrahigh-frequency (microwave plasma torch with a combined (nitrogen, methane plasma-forming environment, and microwave output of up to 2 kW, continuously. We demonstrate the possibility of using it in order to process natural and associated petroleum (APG gas into valuable products (hydrogen and carbon nanomaterial CNM with up to 70% efficiency. Based on the developed microwave plasma torch, we developed an apparatus capable of converting hydrocarbon feedstock at a capacity of 50 g/h yielding CNM and hydrogen of up to 70 vol. %. In its mobile small-tonnage version, this technology can be used on gas-condensate fields.

  3. Solar terrestrial coupling through space plasma processes

    Energy Technology Data Exchange (ETDEWEB)

    Birn, J. [and others

    2000-12-01

    This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project investigates plasma processes that govern the interaction between the solar wind, charged particles ejected from the sun, and the earth's magnetosphere, the region above the ionosphere governed by the terrestrial magnetic field. Primary regions of interest are the regions where different plasma populations interact with each other. These are regions of particularly dynamic plasma behavior, associated with magnetic flux and energy transfer and dynamic energy release. The investigations concerned charged particle transport and energization, and microscopic and macroscopic instabilities in the magnetosphere and adjacent regions. The approaches combined space data analysis with theory and computer simulations.

  4. Use of a probing pulsed magnetic field for determining plasma parameters

    Science.gov (United States)

    Rousskikh, A. G.; Oreshkin, V. I.; Zhigalin, A. S.; Yushkov, G. Yu.

    2016-11-01

    A novel, simple, and readily usable method is proposed for measuring the electrical conductivity and temperature of a plasma. The method is based on the interaction of the test plasma with a pulsed magnetic field. The electric signals induced by the magnetic field in the circuits of two probes (miniature solenoids), one immersed in the test plasma and the other placed outside the plasma, provide data for estimating the plasma parameters. The method was verified experimentally by determining the parameters of the plasma flows generated in the cathode spots high-current pulsed vacuum arcs that were used to form cylindrical shells of bismuth Z-pinch plasma.

  5. General collision branching processes with two parameters

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A new class of branching models,the general collision branching processes with two parameters,is considered in this paper.For such models,it is necessary to evaluate the absorbing probabilities and mean extinction times for both absorbing states.Regularity and uniqueness criteria are firstly established.Explicit expressions are then obtained for the extinction probability vector,the mean extinction times and the conditional mean extinction times.The explosion behavior of these models is investigated and an explicit expression for mean explosion time is established.The mean global holding time is also obtained.It is revealed that these properties are substantially different between the super-explosive and sub-explosive cases.

  6. Plasma process control for improved PEO coatings on magnesium alloys

    Science.gov (United States)

    Hussein, Riyad Omran

    Plasma Electrolytic Oxidation (PEO) is a high voltage plasma-assisted oxidation process uses an environmentally-friendly aqueous electrolyte to oxidize the metal surfaces to form ceramic oxide coatings which impart a high corrosion and wear resistance. One of the main advantages of PEO process is that it can be applied to treat samples with complex shapes, and surfaces with different composition and microstructure. The PEO process of Mg alloys is strongly influenced by such parameters as electrolyte composition and concentration, current or voltage applied and substrate alloy. Generally, these parameters have a direct influence on the discharging behavior. The discharges play an essential role in the formation and resulting composition of the 3-layer oxide structure. A detailed knowledge of the coating mechanisms is extremely important in order to produce a desired coating quality to reach the best performance of the PEO coatings in terms of corrosion resistance and tribological properties (wear rate, COF). During PEO processing of magnesium, some of the metal cations are transferred outwards from the substrate and react with anions to form ceramic coatings. Also, due to the high electric field in the discharge channels, oxygen anions transfer towards the magnesium substrate and react with Mg2+ cations to form a ceramic coating. Although, in general, PEO coating of Mg alloys produces the three-layered structure, the relative proportions of the three-layers are strongly influenced by the PEO processing parameters. In PEO process, the ceramic coating grows inwards to the alloy substrate and outwards to the coating surface simultaneously. For the coating growth, there are three simultaneous processes taking place, namely the electrochemical, the plasma chemical reactions and thermal diffusion. Optical emission spectroscopy (OES) was employed for the discharge characterization by following the substrate and electrolyte element present in the plasma discharge during the

  7. Generation of low-temperature air plasma for food processing

    Science.gov (United States)

    Stepanova, Olga; Demidova, Maria; Astafiev, Alexander; Pinchuk, Mikhail; Balkir, Pinar; Turantas, Fulya

    2015-11-01

    The project is aimed at developing a physical and technical foundation of generating plasma with low gas temperature at atmospheric pressure for food industry needs. As known, plasma has an antimicrobial effect on the numerous types of microorganisms, including those that cause food spoilage. In this work an original experimental setup has been developed for the treatment of different foods. It is based on initiating corona or dielectric-barrier discharge in a chamber filled with ambient air in combination with a certain helium admixture. The experimental setup provides various conditions of discharge generation (including discharge gap geometry, supply voltage, velocity of gas flow, content of helium admixture in air and working pressure) and allows for the measurement of the electrical discharge parameters. Some recommendations on choosing optimal conditions of discharge generation for experiments on plasma food processing are developed.

  8. Revisiting linear plasma waves for finite value of the plasma parameter

    Science.gov (United States)

    Grismayer, Thomas; Fahlen, Jay; Decyk, Viktor; Mori, Warren

    2010-11-01

    We investigate through theory and PIC simulations the Landau-damping of plasma waves with finite plasma parameter. We concentrate on the linear regime, γφB, where the waves are typically small and below the thermal noise. We simulate these condition using 1,2,3D electrostatic PIC codes (BEPS), noting that modern computers now allow us to simulate cases where (nλD^3 = [1e2;1e6]). We study these waves by using a subtraction technique in which two simulations are carried out. In the first, a small wave is initialized or driven, in the second no wave is excited. The results are subtracted to provide a clean signal that can be studied. As nλD^3 is decreased, the number of resonant electrons can be small for linear waves. We show how the damping changes as a result of having few resonant particles. We also find that for small nλD^3 fluctuations can cause the electrons to undergo collisions that eventually destroy the initial wave. A quantity of interest is the the life time of a particular mode which depends on the plasma parameter and the wave number. The life time is estimated and then compared with the numerical results. A surprising result is that even for large values of nλD^3 some non-Vlasov discreteness effects appear to be important.

  9. Process efficiency simulation for key process parameters in biological methanogenesis

    Directory of Open Access Journals (Sweden)

    Sébastien Bernacchi

    2014-09-01

    Full Text Available New generation biofuels are a suitable approach to produce energy carriers in an almost CO2 neutral way. A promising reaction is the conversion of CO2 and H2 to CH4. This contribution aims at elucidating a bioprocess comprised of a core reaction unit using microorganisms from the Archaea life domain, which metabolize CO2 and H2 to CH4, followed by a gas purification step. The process is simulated and analyzed thermodynamically using the Aspen Plus process simulation environment. The goal of the study was to quantify effects of process parameters on overall process efficiency using a kinetic model derived from previously published experimental results. The used empirical model links the production rate of CH4 and biomass to limiting reactant concentrations. In addition, Aspen Plus was used to improve bioprocess quantification. Impacts of pressure as well as dilution of reactant gas with up to 70% non-reactive gas on overall process efficiency was evaluated. Pressure in the reactor unit of 11 bar at 65℃ with a pressure of 21 bar for gas purification led to an overall process efficiency comprised between 66% and 70% for gaseous product and between 73% and 76% if heat of compression is considered a valuable product. The combination of 2 bar pressure in the reactor and 21 bar for purification was the most efficient combination of parameters. This result shows Aspen Plus potential for similar bioprocess development as it accounts for the energetic aspect of the entire process. In fact, the optimum for the overall process efficiency was found to differ from the optimum of the reaction unit. High efficiency of over 70% demonstrates that biological methanogenesis is a promising alternative for a chemical methanation reaction.

  10. Modeling a short cold cathode DC discharge device with controllable plasma parameters

    Science.gov (United States)

    Kudryavtsev, Anatoly; Adams, Steven; Demidov, Vladimir; Bogdanov, Yevgeny

    2009-11-01

    A short (without positive column) DC gas-discharge device with a cold cathode has been modeled. The device consists of the plane disk-shaped cathode and anode while the inter-electrode gap is bounded by a cylindrical wall. The cathode and anode are each 2.5 cm in diameter, and the inter-electrode gap is 12 mm. The wall is made of conducting parts divided by an insulator. The modeling has been performed for argon plasma at 1 Torr pressure. It is demonstrated in the model that spatial distributions of electron density and temperature and argon metastable atom density depend on the DC voltage applied to different conducting parts of the wall. Applied voltage can trap within the device volume energetic electrons arising from atomic and molecular processes in the plasma. This leads to a modification in the heating of slow electrons by energetic electrons and as a result modifies the controlling plasma parameters.

  11. Frequency dependent plasma characteristics in a capacitively coupled 300 mm wafer plasma processing chamber

    Energy Technology Data Exchange (ETDEWEB)

    Hebner, Gregory A [Sandia National Laboratories, Albuquerque NM 87185-1423 (United States); Barnat, Edward V [Sandia National Laboratories, Albuquerque NM 87185-1423 (United States); Miller, Paul A [Sandia National Laboratories, Albuquerque NM 87185-1423 (United States); Paterson, Alex M [Applied Materials, 974 Arques Avenue, Sunnyvale CA, 94086 (United States); Holland, John P [Applied Materials, 974 Arques Avenue, Sunnyvale CA, 94086 (United States)

    2006-11-01

    Argon plasma characteristics in a dual-frequency, capacitively coupled, 300 mm-wafer plasma processing system were investigated for rf drive frequencies between 10 and 190 MHz. We report spatial and frequency dependent changes in plasma parameters such as line-integrated electron density, ion saturation current, optical emission and argon metastable density. For the conditions investigated, the line-integrated electron density was a nonlinear function of drive frequency at constant rf power. In addition, the spatial distribution of the positive ions changed from uniform to peaked in the centre as the frequency was increased. Spatially resolved optical emission increased with frequency and the relative optical emission at several spectral lines depended on frequency. Argon metastable density and spatial distribution were not a strong function of drive frequency. Metastable temperature was approximately 400 K.

  12. Analyses of plasma parameter profiles in JT-60U

    Energy Technology Data Exchange (ETDEWEB)

    Shirai, Hiroshi; Shimizu, Katsuhiro; Hayashi, Nobuhiko [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Itakura, Hirofumi; Takase, Keizou [CSK Co. Ltd., Tokyo (Japan)

    2001-01-01

    The methods how diagnostics data are treated as the surface quantity of magnetic surface and processed to the profile data in the JT-60U plasmas are summarized. The MHD equilibrium obtained by solving Grad-Shafranov equation on the MHD equilibrium calculation and registration software FBEQU are saved shot by shot as a database. Various experimental plasma data measured at various geometrical positions on JT-60 are mapped onto the MHD equilibrium and treated as functions of the volume averaged minor radius {rho} on the experimental data time slice monitoring software SLICE. Experimental data are integrated and edited on SLICE. The experimental data measured as the line integral values are transformed by Able inversion. The mapped data are fitted to a functional form and saved to the profile database MAP-DB. SLICE can also read data from MAP-DB and redisplay and transform them. In addition, SLICE can generate the profile data TOKRD as run data for orbit following Monte-Carlo (OFMC) code, analyzer for current drive consistent with MHD equilibrium (ACCOME) code and tokamak predictive and interpretive code system (TOPICS). (author)

  13. Life Prediction of Atmospheric Plasma-Sprayed Thermal Barrier Coatings Using Temperature-Dependent Model Parameters

    Science.gov (United States)

    Zhang, B.; Chen, Kuiying; Baddour, N.; Patnaik, P. C.

    2017-06-01

    The failure analysis and life prediction of atmospheric plasma-sprayed thermal barrier coatings (APS-TBCs) were carried out for a thermal cyclic process. A residual stress model for the top coat of APS-TBC was proposed and then applied to life prediction. This residual stress model shows an inversion characteristic versus thickness of thermally grown oxide. The capability of the life model was demonstrated using temperature-dependent model parameters. Using existing life data, a comparison of fitting approaches of life model parameters was performed. A larger discrepancy was found for the life predicted using linearized fitting parameters versus temperature compared to those using non-linear fitting parameters. A method for integrating the residual stress was proposed by using the critical time of stress inversion. The role of the residual stresses distributed at each individual coating layer was explored and their interplay on the coating's delamination was analyzed.

  14. Optimization of the process of plasma ignition of coal

    Energy Technology Data Exchange (ETDEWEB)

    Peregudov, V.S. [Russian Academy of Sciences, Novosibirsk (Russian Federation)

    2009-04-15

    Results are given of experimental and theoretical investigations of plasma ignition of coal as a result of its thermochemical preparation in application to the processes of firing up a boiler and stabilizing the flame combustion. The experimental test bed with a commercial-scale burner is used for determining the conditions of plasma ignition of low-reactivity high-ash anthracite depending on the concentration of coal in the air mixture and velocity of the latter. The calculations produce an equation (important from the standpoint of practical applications) for determining the energy expenditure for plasma ignition of coal depending on the basic process parameters. The tests reveal the difficulties arising in firing up a boiler with direct delivery of pulverized coal from the mill to furnace. A scheme is suggested, which enables one to reduce the energy expenditure for ignition of coal and improve the reliability of the process of firing up such a boiler. Results are given of calculation of plasma thermochemical preparation of coal under conditions of lower concentration of oxygen in the air mixture.

  15. The effect of thermophoresis on the discharge parameters in complex plasma experiments

    CERN Document Server

    Land, Victor; Creel, James; Schmoke, Jimmy; Cook, Mike; Matthews, Lorin; Hyde, Truell

    2010-01-01

    Thermophoresis is a tool often applied in complex plasma experiments. One of the usual stated benefits over other experimental tools is that changes induced by thermophoresis neither directly depend on, nor directly influence, the plasma parameters. From electronic data, plasma emission profiles in the sheath, and Langmuir probe data in the plasma bulk, we conclude that this assumption does not hold. An important effect on the levitation of dust particles in argon plasma is observed as well. The reason behind the changes in plasma parameters seems to be the change in neutral atom density accompanying the increased gas temperature while running at constant pressure.

  16. The effect of electrode heating on the discharge parameters in complex plasma experiments

    Energy Technology Data Exchange (ETDEWEB)

    Land, Victor; Carmona-Reyes, Jorge; Creel, James; Schmoke, Jimmy; Cook, Mike; Matthews, Lorin; Hyde, Truell, E-mail: victor_land@baylor.edu [Center for Astrophysics, Space Physics, and Engineering Research, Baylor University, Waco, TX, 76798-7316 (United States)

    2011-02-15

    Thermophoresis is a tool often applied in complex plasma experiments. One of the usual stated benefits over other experimental tools is that electrode temperature changes required to induce thermophoresis do not directly influence the plasma parameters. From electronic data, plasma emission profiles in the sheath, and Langmuir probe data in the plasma bulk, we conclude that this assumption does not hold. An important effect on the levitation of dust particles in argon plasma is observed as well. The reason behind the changes in plasma parameters seems to be the change in neutral atom density accompanying the increased gas temperature while running at constant pressure.

  17. Rocket measurements within a polar cap arc - Plasma, particle, and electric circuit parameters

    Science.gov (United States)

    Weber, E. J.; Ballenthin, J. O.; Basu, S.; Carlson, H. C.; Hardy, D. A.; Maynard, N. C.; Kelley, M. C.; Fleischman, J. R.; Pfaff, R. F.

    1989-01-01

    Results are presented from the Polar Ionospheric Irregularities Experiment (PIIE), conducted from Sondrestrom, Greenland, on March 15, 1985, designed for an investigation of processes which lead to the generation of small-scale (less than 1 km) ionospheric irregularities within polar-cap F-layer auroras. An instrumented rocket was launched into a polar cap F layer aurora to measure energetic electron flux, plasma, and electric circuit parameters of a sun-aligned arc, coordinated with simultaneous measurements from the Sondrestrom incoherent scatter radar and the AFGL Airborne Ionospheric Observatory. Results indicated the existence of two different generation mechanisms on the dawnside and duskside of the arc. On the duskside, parameters are suggestive of an interchange process, while on the dawnside, fluctuation parameters are consistent with a velocity shear instability.

  18. Nonlinear Optical Parameters of Magnetoactive Semiconductor-Plasmas

    Science.gov (United States)

    Singh, M.; Joseph, D.; Duhan, S.

    The nonlinear optical parameters (absorption coefficient and refractive index) of semiconductor-plasmas subjected to a transverse magnetic field have been investigated analytically. By employing the coupled-mode scheme, an expression of third-order optical susceptibility and resultant nonlinear absorption and refractive index of the medium are obtained. The analysis has been applied to both cases, viz., centrosymmetric (β = 0) and noncentrosymmetric (β ≠ 0) in the presence of magnetic field. The numerical estimates are made for InSb crystal at liquid nitrogen temperature duly irradiated by a 10-nanosecond pulsed 10.6 μm CO2 laser. The influence of doping concentration and magnetic field on both the nonlinear absorption and refractive index has been explored, and the results are found to be well in agreement with theory and experiment. Analysis further establishes that absorption coefficient and refractive index can be controlled with precision in semiconductors by the proper selection of doping concentration and an external magnetic field, and hence these media may be used for fabrication of fast cubic nonlinear optical devices under off-resonant transition regime.

  19. The variable polarity plasma arc welding process: Characteristics and performance

    Science.gov (United States)

    Hung, R. J.; Zhu, G. J.

    1991-01-01

    Significant advantages of the Variable Polarity Plasma Arc (VPPA) Welding Process include faster welding, fewer repairs, less joint preparation, reduced weldment distortion, and absence of porosity. The power distribution was analyzed for an argon plasma gas flow constituting the fluid in the VPPA Welding Process. The major heat loss at the torch nozzle is convective heat transfer; in the space between the outlet of the nozzle and the workpiece; radiative heat transfer; and in the keyhole in the workpiece, convective heat transfer. The power absorbed at the workpiece produces the molten puddle that solidifies into the weld bead. Crown and root widths, and crown and root heights of the weld bead are predicted. The basis is provided for an algorithm for automatic control of VPPA welding machine parameters to obtain desired weld bead dimensions.

  20. Spectroscopic studies of the parameters of plasma jets during their propagation in the background plasma on the PF-3 facility

    Science.gov (United States)

    Dan’ko, S. A.; Ananyev, S. S.; Kalinin, Yu G.; Krauz, V. I.; Myalton, V. V.

    2017-04-01

    This paper presents measurement results of neon and helium plasma parameters in axial jets generated in plasma focus discharge. They were obtained in the course of experiments on laboratory modeling of astrophysical jets performed at the PF-3 facility. The plasma concentration was determined according to Stark broadening of spectral lines; the ionization temperature was determined by the average ion charge. The values of the concentration and temperature of jet plasma and background plasma at two distances from the pinch are also presented. In addition, an estimation was made of the heat content losses of the neon and helium jets during their movement through the surrounding medium.

  1. Evolution of plasma parameters in an Ar-N2/He inductive plasma source with magnetic pole enhancement

    Science.gov (United States)

    Maria, Younus; N, U. Rehman; M, Shafiq; M, Naeem; M, Zaka-Ul-Islam; M, Zakaullah

    2017-02-01

    Magnetic pole enhanced inductively coupled plasmas (MaPE-ICPs) are a promising source for plasma-based etching and have a wide range of material processing applications. In the present study Langmuir probe and optical emission spectroscopy were used to monitor the evolution of plasma parameters in a MaPE-ICP Ar-N2/He mixture plasma. Electron density ({n}{{e}}) and temperature ({T}{{e}}), excitation temperature ({T}{{exc}}), plasma potential ({V}{{p}}), skin depth (δ ) and the evolution of the electron energy probability function (EEPF) are reported as a function of radiofrequency (RF) power, pressure and argon concentration in the mixture. It is observed that {n}{{e}} increases while {T}{{e}} decreases with increase in RF power and argon concentration in the mixture. The emission intensity of the argon line at 750.4 nm is also used to monitor the variation of the ‘high-energy tail’ of the EEPF with RF power and gas pressure. The EEPF has a ‘bi-Maxwellian’ distribution at low RF powers and higher pressure in a pure {{{N}}}2 discharge. However, it evolves into a ‘Maxwellian’ distribution at RF powers greater than 70 W for pure {{{N}}}2, and at 50 W for higher argon concentrations in the mixture. The effect of argon concentration on the temperatures of two electron groups in the ‘bi-Maxwellian’ EEPF is examined. The temperature of the low-energy electron group {T}{{L}} shows a decreasing trend with argon addition until the ‘thermalization’ of the two temperatures occurs, while the temperature of high-energy electrons {T}{{H}} decreases continuously.

  2. Parameters influencing plasma column potential in a reflex discharge

    Science.gov (United States)

    Liziakin, G. D.; Gavrikov, A. V.; Murzaev, Y. A.; Usmanov, R. A.; Smirnov, V. P.

    2016-12-01

    Distribution of electrostatic potential in direct current reflex discharge plasma has been studied experimentally. Measurements have been conducted by the single floating probe method. The influence of 0-0.2 T magnetic field, 1-200 mTorr pressure, 0-2 kV discharge voltage, and electrodes geometry on plasma column electrostatic potential was investigated. The possibility for the formation of a preset potential profile required for the realization of plasma separation of spent nuclear fuel was demonstrated.

  3. Spatial control of processing plasmas in a multicusp plasma source equipped with a movable magnetic filter

    Energy Technology Data Exchange (ETDEWEB)

    Fukumasa, O.; Naitou, H.; Sakiyama, S. (Yamaguchi Univ., Yamaguchi (Japan))

    1991-12-20

    The plasma chemical vapor deposition (p-CVD) method has been used in the preparation of various sorts of thin films such as hydrogenated amorphous silicon films and hydrogenated amorphous carbon films, etc. and the application feasibility of a magnetically filtered multicusp plasma source has been studied. In this paper, it is confirmed that plasma parameters (H {sub 2} - ch {sub 4} or Ar-CH {sub 4} plasmas) are spatially well controlled by using both a movable magnetic filter and a plasma grid. Plasma parameters change sharply across the magnetic filter at any filter position and the whole plasma is divided clearly into the region of source plasma with high-energy electrons and the region of diffused plasma without high-energy electrons. Concerning the role of the magnetic filter which reflects preferentially high-energy electrons, a study is made through computer simulation. 7 refs., 9 figs.

  4. Relationship between process parameters and properties of multifunctional needlepunched geotextiles

    CSIR Research Space (South Africa)

    Rawal, A

    2006-04-01

    Full Text Available , and filtration. In this study, the effect of process parameters, namely, feed rate, stroke frequency, and depth of needle penetration has been investigated on various properties of needlepunched geotextiles. These process parameters are then empirically related...

  5. Real-Time Fault Classification for Plasma Processes

    OpenAIRE

    Yang, Ryan; Chen, Rongshun

    2011-01-01

    Plasma process tools, which usually cost several millions of US dollars, are often used in the semiconductor fabrication etching process. If the plasma process is halted due to some process fault, the productivity will be reduced and the cost will increase. In order to maximize the product/wafer yield and tool productivity, a timely and effective fault process detection is required in a plasma reactor. The classification of fault events can help the users to quickly identify fault processes, ...

  6. Radiant-and-plasma technology for coal processing

    OpenAIRE

    Vladimir Messerle; Alexander Ustimenko

    2012-01-01

    Radiant-and-plasma technology for coal processing is presented in the article. Thermodynamic computation and experiments on plasma processing of bituminous coal preliminary electron-beam activated were fulfilled in comparison with plasma processing of the coal. Positive influence of the preliminary electron-beam activation of coal on synthesis gas yield was found. Experiments were carried out in the plasma gasifier of 100 kW power. As a result of the measurements of material and heat balance ...

  7. Multi-parameter gradient procedure for polarimetry data inversion in tokamak plasma

    Energy Technology Data Exchange (ETDEWEB)

    Chrzanowski, J., E-mail: j.chrzanowski@am.szczecin.pl [Maritime University, Szczecin Wały Chrobrego 1/2 (Poland); Kravtsov, Yu. A. [Maritime University, Szczecin Wały Chrobrego 1/2 (Poland); Mazon, D. [Association Euratom/CEA, CEA Cadarache DSM/IRFM, 13108 St. Paul lez Durance Cedex (France); JET, Culham (United Kingdom)

    2013-10-15

    Highlights: ► We use gradient procedure to fit plasma parameters to polarimetric data. ► Calculations are performed in developed by authors angular variables technique. ► Numerical results are compared with experimentally measured angular parameters. ► We observe satisfied accuracy of inversion procedure after several iterations. -- Abstract: Multi-parameter gradient procedure is suggested which allows fitting tokamak plasma model to polarimetric data. One of the simplest version of gradient procedure deals with four parameters model: maximum values of electron density, maximum value of electric current density in plasma, common radius of electron density, electric current distributions and increment of the safety factor inside plasma. Using recently developed by authors angular variables technique (AVT) in plasma polarimetry we may compute angular parameters of polarization ellipse for a given set of four plasma parameters and compare them with experimentally measured angular parameters. With angular parameters, measured in two channels polarimetric system (two azimuthal and two ellipticity angles, totally four experimental values). Applying then gradient procedure for squared difference between computed and measured parameters, we find four parameters of plasma model and thereby perform inversion of polarimetric data. Numerical simulations have approved that gradient procedure provides acceptable accuracy of inversion already after several iterations.

  8. Investigation of the electron capture process in semiclassical plasma

    Directory of Open Access Journals (Sweden)

    Seisembayeva Madina M.

    2016-06-01

    Full Text Available In this work, the process of electron capture in partially ionized plasma is considered. Electron-atom interaction was described by the effective interaction potential, which takes into account the screening effect at large distances and the diffraction effect at the small distances. The results of numerical calculations of the electron capture radius, differential cross-section for different values of the coupling and density parameters are presented. The differential cross-section was obtained on the basis of perturbation theory and also by solving of the equation of motion of the projectile electron.

  9. Advanced plasma etching processes for dielectric materials in VLSI technology

    Science.gov (United States)

    Wang, Juan Juan

    Manufacturable plasma etching processes for dielectric materials have played an important role in the Integrated Circuits (IC) industry in recent decades. Dielectric materials such as SiO2 and SiN are widely used to electrically isolate the active device regions (like the gate, source and drain from the first level of metallic interconnects) and to isolate different metallic interconnect levels from each other. However, development of new state-of-the-art etching processes is urgently needed for higher aspect ratio (oxide depth/hole diameter---6:1) in Very Large Scale Integrated (VLSI) circuits technology. The smaller features can provide greater packing density of devices on a single chip and greater number of chips on a single wafer. This dissertation focuses on understanding and optimizing of several key aspects of etching processes for dielectric materials. The challenges are how to get higher selectivity of oxide/Si for contact and oxide/TiN for vias; tight Critical Dimension (CD) control; wide process margin (enough over-etch); uniformity and repeatability. By exploring all of the parameters for the plasma etch process, the key variables are found and studied extensively. The parameters investigated here are Power, Pressure, Gas ratio, and Temperature. In particular, the novel gases such as C4F8, C5F8, and C4F6 were studied in order to meet the requirements of the design rules. We also studied CF4 that is used frequently for dielectric material etching in the industry. Advanced etch equipment was used for the above applications: the medium-density plasma tools (like Magnet-Enhanced Reactive Ion Etching (MERIE) tool) and the high-density plasma tools. By applying the Design of Experiments (DOE) method, we found the key factors needed to predict the trend of the etch process (such as how to increase the etch rates, selectivity, etc.; and how to control the stability of the etch process). We used JMP software to analyze the DOE data. The characterization of the

  10. Effect of plasma parameters on characteristics of silicon nitride film deposited by single and dual frequency plasma enhanced chemical vapor deposition

    Science.gov (United States)

    Sahu, B. B.; Yin, Yongyi; Han, Jeon G.

    2016-03-01

    This work investigates the deposition of hydrogenated amorphous silicon nitride films using various low-temperature plasmas. Utilizing radio-frequency (RF, 13.56 MHz) and ultra-high frequency (UHF, 320 MHz) powers, different plasma enhanced chemical vapor deposition processes are conducted in the mixture of reactive N2/NH3/SiH4 gases. The processes are extensively characterized using different plasma diagnostic tools to study their plasma and radical generation capabilities. A typical transition of the electron energy distribution function from single- to bi-Maxwellian type is achieved by combining RF and ultra-high powers. Data analysis revealed that the RF/UHF dual frequency power enhances the plasma surface heating and produces hot electron population with relatively low electron temperature and high plasma density. Using various film analysis methods, we have investigated the role of plasma parameters on the compositional, structural, and optical properties of the deposited films to optimize the process conditions. The presented results show that the dual frequency power is effective for enhancing dissociation and ionization of neutrals, which in turn helps in enabling high deposition rate and improving film properties.

  11. Plasma arc cutting optimization parameters for aluminum alloy with two thickness by using Taguchi method

    Science.gov (United States)

    Abdulnasser, B.; Bhuvenesh, R.

    2016-07-01

    Manufacturing companies define the qualities of thermal removing process based on the dimension and physical appearance of the cutting material surface. The surface roughness of the cutting area for the material and the material removal rate being removed during the manual plasma arc cutting process were importantly considered. Plasma arc cutter machine model PS-100 was used to cut the specimens made from aluminium alloy 1100 manually based on the selected parameters setting. Two different thicknesses of specimens, 3mm and 6mm were used. The material removal rate (MRR) was measured by determining the difference between the weight of specimens before and after the cutting process. The surface roughness (Ra) was measured by using MITUTOYO CS-3100 machine and analysis was conducted to determine the average roughness (Ra) value, Taguchi method was utilized as an experimental layout to obtain MRR and Ra values. The results indicate that the current and cutting speed is the most significant parameters, followed by the arc gap for both rate of material removal and surface roughness.

  12. Molecular processes in plasmas collisions of charged particles with molecules

    CERN Document Server

    Itikawa, Yukikazu

    2007-01-01

    Molecular Processes in Plasmas describes elementary collision processes in plasmas, particularly those involving molecules or molecular ions. Those collision processes (called molecular processes) maintain plasmas, produce reactive species and emissions, and play a key role in energy balance in plasmas or more specifically in determining the energy distribution of plasma particles. Many books on plasma physics mention the elementary processes, but normally rather briefly. They only touch upon the general feature or fundamental concept of the collision processes. On the other hand, there are many books on atomic and molecular physics, but most of them are too general or too detailed to be useful to people in the application fields. The present book enumerates all the possible processes in the collisions of electrons, as well as ions, with molecules. For each process, a compact but informative description of its characteristics is given together with illustrative examples. Since the author has much experience a...

  13. Lagrangian coherent structures and plasma transport processes

    CERN Document Server

    Falessi, M V; Schep, T J

    2015-01-01

    A dynamical system framework is used to describe transport processes in plasmas embedded in a magnetic field. For periodic systems with one degree of freedom the Poincar\\'e map provides a splitting of the phase space into regions where particles have different kinds of motion: periodic, quasi-periodic or chaotic. The boundaries of these regions are transport barriers; i.e., a trajectory cannot cross such boundaries during the whole evolution of the system. Lagrangian Coherent Structure (LCS) generalize this method to systems with the most general time dependence, splitting the phase space into regions with different qualitative behaviours. This leads to the definition of finite-time transport barriers, i.e. trajectories cannot cross the barrier for a finite amount of time. This methodology can be used to identify fast recirculating regions in the dynamical system and to characterize the transport between them.

  14. Plasma Discharge Process in a Pulsed Diaphragm Discharge System

    Science.gov (United States)

    Duan, Jianjin; Hu, Jue; Zhang, Chao; Wen, Yuanbin; Meng, Yuedong; Zhang, Chengxu

    2014-12-01

    As one of the most important steps in wastewater treatment, limited study on plasma discharge process is a key challenge in the development of plasma applications. In this study, we focus on the plasma discharge process of a pulsed diaphragm discharge system. According to the analysis, the pulsed diaphragm discharge proceeds in seven stages: (1) Joule heating and heat exchange stage; (2) nucleated site formation; (3) plasma generation (initiation of the breakdown stage); (4) avalanche growth and plasma expansion; (5) plasma contraction; (6) termination of the plasma discharge; and (7) heat exchange stage. From this analysis, a critical voltage criterion for breakdown is obtained. We anticipate this finding will provide guidance for a better application of plasma discharges, especially diaphragm plasma discharges.

  15. Physical processes associated with current collection by plasma contactors

    Science.gov (United States)

    Katz, Ira; Davis, Victoria A.

    1990-01-01

    Recent flight data confirms laboratory observations that the release of neutral gas increases plasma sheath currents. Plasma contactors are devices which release a partially ionized gas in order to enhance the current flow between a spacecraft and the space plasma. Ionization of the expellant gas and the formation of a double layer between the anode plasma and the space plasma are the dominant physical processes. A theory is presented of the interaction between the contactor plasma and the background plasma. The conditions for formation of a double layer between the two plasmas are derived. Double layer formation is shown to be a consequence of the nonlinear response of the plasmas to changes in potential. Numerical calculations based upon this model are compared with laboratory measurements of current collection by hollow cathode-based plasma contactors.

  16. Numerical simulation of distributed parameter processes

    CERN Document Server

    Colosi, Tiberiu; Unguresan, Mihaela-Ligia; Muresan, Vlad

    2013-01-01

    The present monograph defines, interprets and uses the matrix of partial derivatives of the state vector with applications for the study of some common categories of engineering. The book covers broad categories of processes that are formed by systems of partial derivative equations (PDEs), including systems of ordinary differential equations (ODEs). The work includes numerous applications specific to Systems Theory based on Mpdx, such as parallel, serial as well as feed-back connections for the processes defined by PDEs. For similar, more complex processes based on Mpdx with PDEs and ODEs as components, we have developed control schemes with PID effects for the propagation phenomena, in continuous media (spaces) or discontinuous ones (chemistry, power system, thermo-energetic) or in electro-mechanics (railway – traction) and so on. The monograph has a purely engineering focus and is intended for a target audience working in extremely diverse fields of application (propagation phenomena, diffusion, hydrodyn...

  17. Atmospheric Pressure Plasma Processing for Polymer Adhesion: A Review

    DEFF Research Database (Denmark)

    Kusano, Yukihiro

    2014-01-01

    Atmospheric pressure plasma processing has attracted significant interests over decades due to its usefulness and a variety of applications. Adhesion improvement of polymer surfaces is among the most important applications of atmospheric pressure plasma treatment. Reflecting recent significant de...... development of the atmospheric pressure plasma processing, this work presents its fundamental aspects, applications, and characterization techniques relevant to adhesion.......Atmospheric pressure plasma processing has attracted significant interests over decades due to its usefulness and a variety of applications. Adhesion improvement of polymer surfaces is among the most important applications of atmospheric pressure plasma treatment. Reflecting recent significant...

  18. Microbial adherence to a nonprecious alloy after plasma nitriding process.

    Science.gov (United States)

    Sonugelen, Mehmet; Destan, Uhmut Iyiyapici; Lambrecht, Fatma Yurt; Oztürk, Berran; Karadeniz, Süleyman

    2006-01-01

    To investigate the microbial adherence to the surfaces of a nonprecious metal alloy after plasma nitriding. The plasma-nitriding process was performed to the surfaces of metals prepared from a nickel-chromium alloy. The microorganisms were labeled with technetium-99m. After the labeling procedure, 60 metal disks were treated with a microorganism for each use. The results revealed that the amount of adherence of all microorganisms on surfaces was changed by plasma-nitriding process; adherence decreased substantially (P plasma nitriding time were not significant (P> .05) With the plasma-nitriding process, the surface properties of nonprecious metal alloys can be changed, leading to decreased microbial adherence.

  19. Parameter optimization model in electrical discharge machining process

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Electrical discharge machining (EDM) process, at present is still an experience process, wherein selected parameters are often far from the optimum, and at the same time selecting optimization parameters is costly and time consuming. In this paper,artificial neural network (ANN) and genetic algorithm (GA) are used together to establish the parameter optimization model. An ANN model which adapts Levenberg-Marquardt algorithm has been set up to represent the relationship between material removal rate (MRR) and input parameters, and GA is used to optimize parameters, so that optimization results are obtained. The model is shown to be effective, and MRR is improved using optimized machining parameters.

  20. Integral electrical characteristics and local plasma parameters of a RF ion thruster

    Energy Technology Data Exchange (ETDEWEB)

    Masherov, P. E.; Riaby, V. A., E-mail: riaby2001@yahoo.com [Research Institute of Applied Mechanics and Electrodynamics of the Moscow Aviation Institute (National Research University), Moscow (Russian Federation); Godyak, V. A. [Electrical Engineering and Computer Science Department, University of Michigan, Ann Arbor, Michigan 48109, USA and RF Plasma Consulting, Brookline, Massachusetts 02446 (United States)

    2016-02-15

    Comprehensive diagnostics has been carried out for a RF ion thruster based on inductively coupled plasma (ICP) source with an external flat antenna coil enhanced by ferrite core. The ICP was confined within a cylindrical chamber with low aspect ratio to minimize plasma loss to the chamber wall. Integral diagnostics of the ICP electrical parameters (RF power balance and coil current) allowed for evaluation of the antenna coils, matching networks, and eddy current loss and the true RF power deposited to plasma. Spatially resolved electron energy distribution functions, plasma density, electron temperatures, and plasma potentials were measured with movable Langmuir probes.

  1. Preliminary Hazards Analysis Plasma Hearth Process

    Energy Technology Data Exchange (ETDEWEB)

    Aycock, M.; Coordes, D.; Russell, J.; TenBrook, W.; Yimbo, P. [Science Applications International Corp., Pleasanton, CA (United States)

    1993-11-01

    This Preliminary Hazards Analysis (PHA) for the Plasma Hearth Process (PHP) follows the requirements of United States Department of Energy (DOE) Order 5480.23 (DOE, 1992a), DOE Order 5480.21 (DOE, 1991d), DOE Order 5480.22 (DOE, 1992c), DOE Order 5481.1B (DOE, 1986), and the guidance provided in DOE Standards DOE-STD-1027-92 (DOE, 1992b). Consideration is given to ft proposed regulations published as 10 CFR 830 (DOE, 1993) and DOE Safety Guide SG 830.110 (DOE, 1992b). The purpose of performing a PRA is to establish an initial hazard categorization for a DOE nuclear facility and to identify those processes and structures which may have an impact on or be important to safety. The PHA is typically performed during and provides input to project conceptual design. The PRA then is followed by a Preliminary Safety Analysis Report (PSAR) performed during Title I and II design. This PSAR then leads to performance of the Final Safety Analysis Report performed during construction, testing, and acceptance and completed before routine operation. Radiological assessments indicate that a PHP facility, depending on the radioactive material inventory, may be an exempt, Category 3, or Category 2 facility. The calculated impacts would result in no significant impact to offsite personnel or the environment. Hazardous material assessments indicate that a PHP facility will be a Low Hazard facility having no significant impacts either onsite or offsite to personnel and the environment.

  2. Plasma generated during underwater pulsed laser processing

    Science.gov (United States)

    Hoffman, Jacek; Chrzanowska, Justyna; Moscicki, Tomasz; Radziejewska, Joanna; Stobinski, Leszek; Szymanski, Zygmunt

    2017-09-01

    The plasma induced during underwater pulsed laser ablation of graphite is studied both experimentally and theoretically. The results of the experiment show that the maximum plasma temperature of 25000 K is reached 20 ns from the beginning of the laser pulse and decreases to 6500 K after 1000 ns. The observed OH absorption band shows that the plasma plume is surrounded by the thin layer of dissociated water vapour at a temperature around 5500 K. The hydrodynamic model applied shows similar maximum plasma temperature at delay times between 14 ns and 30 ns. The calculations show also that already at 14th ns, the plasma electron density reaches 0.97·1027 m-3, which is the critical density for 1064 nm radiation. At the same time the plasma pressure is 2 GPa, which is consisted with earlier measurements of the peak pressure exerted on a target in similar conditions.

  3. Dependence of the source performance on plasma parameters at the BATMAN test facility

    Energy Technology Data Exchange (ETDEWEB)

    Wimmer, C.; Fantz, U. [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany)

    2015-04-08

    The investigation of the dependence of the source performance (high j{sub H{sup −}}, low j{sub e}) for optimum Cs conditions on the plasma parameters at the BATMAN (Bavarian Test MAchine for Negative hydrogen ions) test facility is desirable in order to find key parameters for the operation of the source as well as to deepen the physical understanding. The most relevant source physics takes place in the extended boundary layer, which is the plasma layer with a thickness of several cm in front of the plasma grid: the production of H{sup −}, its transport through the plasma and its extraction, inevitably accompanied by the co-extraction of electrons. Hence, a link of the source performance with the plasma parameters in the extended boundary layer is expected. In order to characterize electron and negative hydrogen ion fluxes in the extended boundary layer, Cavity Ring-Down Spectroscopy and Langmuir probes have been applied for the measurement of the H{sup −} density and the determination of the plasma density, the plasma potential and the electron temperature, respectively. The plasma potential is of particular importance as it determines the sheath potential profile at the plasma grid: depending on the plasma grid bias relative to the plasma potential, a transition in the plasma sheath from an electron repelling to an electron attracting sheath takes place, influencing strongly the electron fraction of the bias current and thus the amount of co-extracted electrons. Dependencies of the source performance on the determined plasma parameters are presented for the comparison of two source pressures (0.6 Pa, 0.45 Pa) in hydrogen operation. The higher source pressure of 0.6 Pa is a standard point of operation at BATMAN with external magnets, whereas the lower pressure of 0.45 Pa is closer to the ITER requirements (p ≤ 0.3 Pa)

  4. Dependence of the source performance on plasma parameters at the BATMAN test facility

    Science.gov (United States)

    Wimmer, C.; Fantz, U.

    2015-04-01

    The investigation of the dependence of the source performance (high jH-, low je) for optimum Cs conditions on the plasma parameters at the BATMAN (Bavarian Test MAchine for Negative hydrogen ions) test facility is desirable in order to find key parameters for the operation of the source as well as to deepen the physical understanding. The most relevant source physics takes place in the extended boundary layer, which is the plasma layer with a thickness of several cm in front of the plasma grid: the production of H-, its transport through the plasma and its extraction, inevitably accompanied by the co-extraction of electrons. Hence, a link of the source performance with the plasma parameters in the extended boundary layer is expected. In order to characterize electron and negative hydrogen ion fluxes in the extended boundary layer, Cavity Ring-Down Spectroscopy and Langmuir probes have been applied for the measurement of the H- density and the determination of the plasma density, the plasma potential and the electron temperature, respectively. The plasma potential is of particular importance as it determines the sheath potential profile at the plasma grid: depending on the plasma grid bias relative to the plasma potential, a transition in the plasma sheath from an electron repelling to an electron attracting sheath takes place, influencing strongly the electron fraction of the bias current and thus the amount of co-extracted electrons. Dependencies of the source performance on the determined plasma parameters are presented for the comparison of two source pressures (0.6 Pa, 0.45 Pa) in hydrogen operation. The higher source pressure of 0.6 Pa is a standard point of operation at BATMAN with external magnets, whereas the lower pressure of 0.45 Pa is closer to the ITER requirements (p ≤ 0.3 Pa).

  5. Increasing plasma parameters using sheared flow stabilization of a Z-pinch

    Science.gov (United States)

    Shumlak, U.; Nelson, B. A.; Claveau, E. L.; Forbes, E. G.; Golingo, R. P.; Hughes, M. C.; Oberto, R. J.; Ross, M. P.; Weber, T. R.

    2017-05-01

    The ZaP and ZaP-HD Flow Z-pinch experiments at the University of Washington have successfully demonstrated that sheared plasma flows can be used as a stabilization mechanism over a range of parameters that has not previously been accessible to long-lived Z-pinch configurations. The stabilization is effective even when the plasma column is compressed to small radii, producing predicted increases in magnetic field and electron temperature. The flow shear value, extent, and duration are shown to be consistent with theoretical models of the plasma viscosity, which places a design constraint on the maximum axial length of a sheared flow stabilized Z-pinch. Measurements of the magnetic field topology indicate simultaneous azimuthal symmetry and axial uniformity along the entire 100 cm length of the Z-pinch plasma. Separate control of plasma acceleration and compression has increased the accessible plasma parameters and has generated stable plasmas with radii of 0.3 cm, as measured with a high resolution digital holographic interferometer. Compressing the plasma with higher pinch currents has produced high magnetic fields (8.5 T) and electron temperatures (1 keV) with an electron density of 2 ×1017 cm-3, while maintaining plasma stability for many Alfvén times (approximately 50 μs). The results suggest that sheared flow stabilization can be applied to extend Z-pinch plasma parameters to high energy densities.

  6. Two-Step Plasma Process for Cleaning Indium Bonding Bumps

    Science.gov (United States)

    Greer, Harold F.; Vasquez, Richard P.; Jones, Todd J.; Hoenk, Michael E.; Dickie, Matthew R.; Nikzad, Shouleh

    2009-01-01

    A two-step plasma process has been developed as a means of removing surface oxide layers from indium bumps used in flip-chip hybridization (bump bonding) of integrated circuits. The two-step plasma process makes it possible to remove surface indium oxide, without incurring the adverse effects of the acid etching process.

  7. Plasma diagnostics in a pulsed accelerator used for material processing

    Energy Technology Data Exchange (ETDEWEB)

    Zhukeshov, A [Science Research Institute of Experimental and Theoretical Physics, al-Farabi Kazakh National University, 96a Tole bi str., 050012 Almaty (Kazakhstan)

    2007-04-15

    Results of research work of a pulsed plasma accelerator, designed as diagnostic and material science stands in SRIETP are presented. We present results on the development of electric and magnetic probes used for measurement of plasma parameters. The physical properties and changes in structure of vanadium alloy, common quality carbon and stainless steels have been investigated as well.

  8. Atomic processes in high-density plasmas

    Energy Technology Data Exchange (ETDEWEB)

    More, R.M.

    1982-12-21

    This review covers dense atomic plasmas such as that produced in inertial confinement fusion. The target implosion physics along with the associated atomic physics, i.e., free electron collision phenomena, electron states I, electron states II, and nonequilibrium plasma states are described. (MOW)

  9. Determination of Some Biochemical Parameters in the Seminal Plasma of German Shepherd Dogs

    OpenAIRE

    GÜNAY, Ülgen

    2003-01-01

    In this study, we aimed to determine the levels of some biochemical parameters in the seminal plasma of German Shepherd dogs. Seven German Shepherd dogs were used as materials. A total of 35 ejaculates, five from each dog, were collected. The seminal plasma of each ejaculate was separated by centrifugation at 5000 rpm for 10 min. Biochemical analyses of the seminal plasma were performed. In conclusion, the average concentrations of total protein, calcium, phosphorus, magnesium, sodium and pot...

  10. Thermomechanical processing of plasma sprayed intermetallic sheets

    Energy Technology Data Exchange (ETDEWEB)

    Hajaligol, Mohammad R. (Midlothian, VA); Scorey, Clive (Cheshire, CT); Sikka, Vinod K. (Oak Ridge, TN); Deevi, Seetharama C. (Midlothian, VA); Fleischhauer, Grier (Midlothian, VA); Lilly, Jr., A. Clifton (Chesterfield, VA); German, Randall M. (State College, PA)

    2001-01-01

    A powder metallurgical process of preparing a sheet from a powder having an intermetallic alloy composition such as an iron, nickel or titanium aluminide. The sheet can be manufactured into electrical resistance heating elements having improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The iron aluminide has an entirely ferritic microstructure which is free of austenite and can include, in weight %, 4 to 32% Al, and optional additions such as .ltoreq.1% Cr, .gtoreq.0.05% Zr .ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Ni, .ltoreq.0.75% C, .ltoreq.0.1% B, .ltoreq.1% submicron oxide particles and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1% rare earth metal, and/or .ltoreq.3% Cu. The process includes forming a non-densified metal sheet by consolidating a powder having an intermetallic alloy composition such as by roll compaction, tape casting or plasma spraying, forming a cold rolled sheet by cold rolling the non-densified metal sheet so as to increase the density and reduce the thickness thereof and annealing the cold rolled sheet. The powder can be a water, polymer or gas atomized powder which is subjecting to sieving and/or blending with a binder prior to the consolidation step. After the consolidation step, the sheet can be partially sintered. The cold rolling and/or annealing steps can be repeated to achieve the desired sheet thickness and properties. The annealing can be carried out in a vacuum furnace with a vacuum or inert atmosphere. During final annealing, the cold rolled sheet recrystallizes to an average grain size of about 10 to 30 .mu.m. Final stress relief annealing can be carried out in the B2 phase temperature range.

  11. Understanding plasma spraying process and characteristics of DC-arc plasma gun (PJ-100

    Directory of Open Access Journals (Sweden)

    Jovana Ružić

    2012-12-01

    Full Text Available The thermal spray processes are a group of coating processes used to apply metallic or non-metallic coatings. In these processes energy sources are used to heat the coating material (in the form of powder, wire, or rod form to a molten or semi-molten state and accelerated towards a prepared surface by either carrier gases or atomization jets. In plasma spraying process, the spraying material is generally in the form of powder and requires a carrier gas to feed the powder into the plasma jet, which is passing between the hot cathode and the cylindrical nozzle-shaped anode. The design of DC plasma gun (PJ - 100 is designed and manufactured in Serbia. Plasma spaying process, the powder injection with the heat, momentum and mass transfers between particles and plasma jet, and the latest developments related to the production of DC plasma gun are described in this article.

  12. Monitoring and Improving the Reliability of Plasma Spray Processes

    Science.gov (United States)

    Mauer, Georg; Rauwald, Karl-Heinz; Mücke, Robert; Vaßen, Robert

    2017-06-01

    Monitoring and improving of process reliability are prevalent issues in thermal spray technology. They are intended to accomplish specific quality characteristics by controlling the process. For this, implicit approaches are in demand to rapidly conclude on relevant coating properties, i.e., they are not directly measured, but it is assumed that the monitored variables are in fact suggestive for them. Such monitoring can be performed in situ (during the running process) instead of measuring coating characteristics explicitly (directly) and ex situ (after the process). Implicit approaches can be based on extrinsic variables (set from outside) as well as on intrinsic parameters (internal, not directly adjustable) having specific advantages and disadvantages, each. In this work, the effects of atmospheric plasma spray process variables are systemized in process schemes. On this basis, different approaches to contribute to improved process reliability are described and assessed paying particular attention to in-flight particle diagnostics. Finally, a new test applying spray bead analysis is introduced and first results are presented.

  13. EFFECT OF PLASMA CUTTING PARAMETERS UPON SHAPES OF BEARING CURVE OF C45 STEEL SURFACE

    Directory of Open Access Journals (Sweden)

    Agnieszka Skoczylas

    2015-08-01

    Full Text Available The article presents the results of studies on the effect of plasma cutting technological parameters upon the shape of bearing curves and the parameters of the curve. The topography of surface formed by plasma cutting were analyzed. For measuring surface roughness and determining the bearing curve the appliance T8000 RC120 – 400 by Hommel-Etamic was used together with software.

  14. Alteration of Lysophosphatidylcholine-Related Metabolic Parameters in the Plasma of Mice with Experimental Sepsis.

    Science.gov (United States)

    Ahn, Won-Gyun; Jung, Jun-Sub; Kwon, Hyeok Yil; Song, Dong-Keun

    2017-04-01

    Plasma concentration of lysophosphatidylcholine (LPC) was reported to decrease in patients with sepsis. However, the mechanisms of sepsis-induced decrease in plasma LPC levels are not currently well known. In mice subjected to cecal ligation and puncture (CLP), a model of polymicrobial peritoneal sepsis, we examined alterations in LPC-related metabolic parameters in plasma, i.e., the plasma concentration of LPC-related substances (i.e., phosphatidylcholine (PC) and lysophosphatidic acid (LPA)), and activities or levels in the plasma of some enzymes that can be involved in the regulation of plasma LPC concentration (i.e., secretory phospholipase A2 (sPLA2), lecithin:cholesterol acyltransferase (LCAT), acyl-CoA:lysophosphatidylcholine acyltransferase (LPCAT), and autotaxin (ATX)), as well as plasma albumin concentration. We found that levels of LPC and albumin and enzyme activities of LCAT, ATX, and sPLA2 were decreased, whereas levels of PC, LPA, and LPCAT1-3 were increased in the plasma of mice subjected to CLP. Bacterial peritonitis led to alterations in all the measured LPC-related metabolic parameters in the plasma, which could potentially contribute to sepsis-induced decrease in plasma LPC levels. These findings could lead to the novel biomarkers of sepsis.

  15. Influence of Processing Parameters on Granularity Distribution of Superalloy Powders during PREP

    Institute of Scientific and Technical Information of China (English)

    Huanming CHEN; Benfu HU; Yiwen ZHANG; Huiying LI; Quanmao YU

    2003-01-01

    In order to investigate the influence of processing parameters on the granularity distribution of superalloy powders during the atomization of plasma rotating electrode processing (PREP), in this paper FGH95 superalloy powders is prepared under different processing conditions by PREP and the influence of PREP processing parameters on the granularity distribution of FGH95 superalloy powders is discussed based on fractal geometry theory. The results show that with the increase of rotating velocity of the self-consuming electrode, the fractal dimension of the granularity distribution increases linearly, which results in the increase of the proportion of smaller powders. The change of interval between plasma gun and the self-consuming electrode has a little effect on the granularity distribution, also the fractal dimension of the granularity distribution changed a little correspondingly.

  16. Reliability of plasma-sprayed coatings: monitoring the plasma spray process and improving the quality of coatings

    Science.gov (United States)

    Fauchais, P.; Vardelle, M.; Vardelle, A.

    2013-06-01

    As for every coating technology, the reliability and reproducibility of coatings are essential for the development of the plasma spraying technology in industrial manufacturing. They mainly depend on the process reliability, equipment and spray booth maintenance, operator training and certification, implementation and use of consistent production practices and standardization of coating testing. This paper deals with the first issue, that is the monitoring and control of the plasma spray process; it does not tackle the coating characterization and testing methods. It begins with a short history of coating quality improvement under plasma spray conditions over the last few decades, details the plasma spray torches used in the industry, the development of the measurements of in-flight and impacting particle parameters and then of sensors. It concludes with the process maps that describe the interrelations between the operating parameters of the spray process, in-flight particle characteristics and coating properties and with the potential of in situ monitoring of the process by artificial neural networks and fuzzy logic methods.

  17. Transformation of state space for two-parameter Markov processes

    Institute of Scientific and Technical Information of China (English)

    周健伟

    1996-01-01

    Let X=(X) be a two-parameter *-Markov process with a transition function (p1, p2, p), where X, takes values in the state space (Er,), T=[0,)2. For each r T, let f, be a measurable transformation of (E,) into the state space (E’r, ). Set Y,=f,(X,), r T. A sufficient condition is given for the process Y=(Yr) still to be a two-parameter *-Markov process with a transition function in terms of transition function (p1, p2, p) and fr. For *-Markov families of two-parameter processes with a transition function, a similar problem is also discussed.

  18. Nova tocha de plasma híbrida para o processamento de materiais New hybrid plasma torch for materials processing

    Directory of Open Access Journals (Sweden)

    Richard Thomas Lermen

    2012-12-01

    Full Text Available O principal objetivo deste artigo foi apresentar um novo dispositivo para o processamento de materiais. Ele consiste em uma tocha de plasma híbrida, a qual é caracterizada pela formação simultânea de dois arcos plasma em apenas um dispositivo, gerando jato (de plasma com elevada densidade de energia. A tocha foi submetida aos seguintes testes experimentais: de funcionamento para verificar possíveis problemas de projeto e seus limites de operação; de caracterização, consistindo em determinar o comprimento do jato de plasma; de sua viabilidade para processamento de materiais (soldagem e corte. Com base nestes testes iniciais, alguns problemas de isolamento elétrico e térmico foram encontrados e resolvidos. Quanto aos resultados dos testes de caracterização, os parâmetros de funcionamento da tocha de plasma híbrida apresentaram influência significativa sobre o comprimento do jato de plasma. Os resultados obtidos nos testes de processamento de materiais foram satisfatórios, ou seja, é possível realizar soldagem e corte com esta tocha de plasma híbrida.The main aim of this paper was to present a new device for materials processing. It consist of a hybrid plasma torch which is characterized by the simultaneous formation of two plasma arcs in one device only, generating a (plasma jet with high energy density. The torch was submitted to the following trials: of operation to identify possible design problems and its operational torch limits; of characterization, consisting in plasma jet length determination; and of viability for materials processing (welding and cutting. Based on these initial trials, some electrical and thermal insulation problems were found and solved. Concerning the results of the characterization trials, the hybrid plasma torch parameters had a significant influence over the plasma jet length. The results obtained in the materials processing trials were satisfactory, i.e., it is possible to carry out welding and

  19. Downstream plasma parameters in laminar shocks from ion kinetics

    Science.gov (United States)

    Gedalin, M.

    2016-10-01

    Ion dynamics in oblique shocks is governed by the macroscopic electric and magnetic fields of the shock front. In laminar shocks, these fields are time-independent and depend only on the coordinate along the shock normal. The shock ramp is narrow and the ion motion across the shock is manifestly non-adiabatic. The ion distribution just behind the ramp is significantly non-gyrotropic. Gyrotropy is achieved well behind the ramp mainly due to the gyrophase mixing. The asymptotic values of the ion density and temperature are determined by the eventual collisionless relaxation of the gyrating ion distribution. Given a distribution at the downstream edge of the ramp, the moments of the distribution after gyrophase mixing are derived using proper spatial averaging. The obtained expressions can be used for independent determination of the downstream plasma state and implementation in Rankine-Hugoniot relations.

  20. Effect of impurities on kinetic transport processes in fusion plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Braun, Stefanie

    2010-12-10

    Within the framework of this thesis, different problems arising in connection with impurities have been investigated. Collisional damping of zonal flows in tokamaks: Since the Coulomb collision frequency increases with increasing ion charge, heavy, highly charged impurities play an important role in this process. The effect of such impurities on the linear response of the plasma to an external potential perturbation, as caused by zonal flows, is calculated with analytical methods. In comparison with a pure plasma, the damping of the flows occurs, as expected, considerably faster; for experimentally relevant parameters, the enhancement exceeds the effective charge Z{sub eff} of the plasma. Impurity transport driven by microturbulence in tokamaks: With regard to impurities, it is especially important whether the resulting flows are directed inwards or outwards, since they are deleterious for core energy confinement on the one hand, but on the other hand help protecting plasma-facing components from too high energy fluxes in the edge region. A semi-analytical model is presented describing the resulting impurity fluxes and the stability boundary of the underlying mode. The main goal is to bridge the gap between, on the one hand, costly numerical simulations, which are applicable to a broad range of problems but yield scarcely traceable results, and, on the other hand, analytical theory, which might ease the interpretation of the results but is so far rather rudimentary. The model is based on analytical formulae whenever possible but resorts to a numerical treatment when the approximations necessary for an analytical solution would lead to a substantial distortion of the results. Both the direction of the impurity flux and the stability boundary are found to depend sensitively on the plasma parameters such as the impurity density and the temperature gradient. Pfirsch-Schlueter transport in stellarators: Due to geometry effects, collisional transport plays a much more

  1. Two-parameter Levy processes along decreasing paths

    CERN Document Server

    Covo, Shai

    2010-01-01

    Let {X_{t_1,t_2}: t_1,t_2 >= 0} be a two-parameter L\\'evy process on R^d. We study basic properties of the one-parameter process {X_{x(t),y(t)}: t \\in T} where x and y are, respectively, nondecreasing and nonincreasing nonnegative continuous functions on the interval T. We focus on and characterize the case where the process has stationary increments.

  2. Analytical estimation of particle shape formation parameters in a plasma-chemical reactor

    Directory of Open Access Journals (Sweden)

    Zhukov Ilya A.

    2017-01-01

    Full Text Available Analytical estimation of particle shape formation parameters in a plasma-chemical reactor implementing the process of thermochemical decomposition of liquid droplet agents (precursors in the flow of a high-temperature gaseous heat-transfer medium was obtained. The basic factor which determines the process is the increase of concentration of a dissolved salt precursor component at the surface of a liquid particle due to solvent evaporation. According to the physical concept of the method of integral balance the diffusion process of concentration change is divided into two stages: the first stage is when the size of gradient layer does not reach the center of a spherical droplet and the second stage when the concentration at the center of a liquid droplet begins to change. The solutions for concentration fields were found for each stage using the method of integral balance taking into account the formation of salt precipitate when the concentration at the surface of the droplet reaches certain equilibrium value. The results of estimation of the influence of various reactor operation parameters and characteristics of initial solution (precursor on the morphology of particles formed – mass fraction and localization of salt precipitate for various levels of evaporation.

  3. Seminal plasma zinc level may be associated with the effect of cigarette smoking on sperm parameters.

    Science.gov (United States)

    Liu, R-Z; Gao, J-C; Zhang, H-G; Wang, R-X; Zhang, Z-H; Liu, X-Y

    2010-01-01

    The aim of this study was to investigate the effect of cigarette smoking on seminal plasma zinc levels and sperm parameters, and to examine the role of seminal plasma zinc. Semen samples from 79 non-smokers and 68 smokers were obtained. There was a significant decrease in seminal plasma zinc in smokers and a clear correlation between seminal plasma zinc levels and the extent of smoking. Sperm parameters (concentration, motility and morphology) among smokers were significantly lower in comparison to non-smokers. These parameters were also significantly decreased among smokers with abnormal zinc levels, while there was no significant difference between non-smokers with normal zinc and non-smokers with abnormal zinc levels. As previous studies have shown that seminal plasma zinc is associated with a decrease of anti-oxidant defences, seminal plasma zinc could be a contributor to the effects of cigarette smoking on sperm parameters. In conclusion, cigarette smoking can affect sperm parameters and this study may help towards providing a mechanistic explanation.

  4. Synthesis and texturization processes of (super)-hydrophobic fluorinated surfaces by atmospheric plasma

    CERN Document Server

    Hubert, Julie; Dufour, Thierry; Vandencasteele, Nicolas; Reniers, François; Viville, Pascal; Lazzaroni, Roberto; Raes, M; Terryn, Herman

    2016-01-01

    The synthesis and texturization processes of fluorinated surfaces by means of atmospheric plasma are investigated and presented through an integrated study of both the plasma phase and the resulting material surface. Three methods enhancing the surface hydrophobicity up to the production of super-hydrophobic surfaces are evaluated: (i) the modification of a polytetrafluoroethylene (PTFE) surface, (ii) the plasma deposition of fluorinated coatings and (iii) the incorporation of nanoparticles into those fluorinated films. In all the approaches, the nature of the plasma gas appears to be a crucial parameter for the desired property. Although a higher etching of the PTFE surface can be obtained with a pure helium plasma, the texturization can only be created if O2 is added to the plasma, which simultaneously decreases the total etching. The deposition of CxFy films by a dielectric barrier discharge leads to hydrophobic coatings with water contact angles (WCAs) of 115{\\textdegree}, but only the filamentary argon d...

  5. T3PS: Tool for Parallel Processing in Parameter Scans

    CERN Document Server

    Maurer, Vinzenz

    2015-01-01

    T3PS is a program that can be used to quickly design and perform parameter scans while easily taking advantage of the multi-core architecture of current processors. It takes an easy to read and write parameter scan definition file format as input. Based on the parameter ranges and other options contained therein, it distributes the calculation of the parameter space over multiple processes and possibly computers. The derived data is saved in a plain text file format readable by most plotting software. The supported scanning strategies include: grid scan, random scan, Markov Chain Monte Carlo, numerical optimization. Several example parameter scans are shown and compared with results in the literature.

  6. Plasma Processes : Minimum dissipative relaxed states in toroidal plasmas

    Indian Academy of Sciences (India)

    R Bhattacharyya; M S Janaki; B Dasgupta

    2000-11-01

    Relaxation of toroidal discharges is described by the principle of minimum energy dissipation together with the constraint of conserved global helicity. The resulting Euler-Lagrange equation is solved in toroidal coordinates for an axisymmetric torus by expressing the solutions in terms of Chandrasekhar-Kendall (C-K) eigenfunctions analytically continued in the complex domain. The C-K eigenfunctions are obtained as hypergeometric functions that are solutions of scalar Helmholtz equation in toroidal coordinates in the large aspect-ratio approximation. Equilibria are constructed by assuming the current to vanish at the edge of plasma. For the = 0; = 0 ( and are the poloidal and toroidal mode numbers respectively) relaxed states, the magnetic field, current, (safety factor) and pressure profiles are calculated for a given value of aspect-ratio of the torus and for different values of the eigenvalue 0. The new feature of the present model is that solutions allow for both tokamak as well as RFP-like behaviour with increase in the values of 0, which is related directly to volt-sec in the experiment.

  7. Plasma Processes : Plasma sprayed alumina coatings for radiation detector development

    Indian Academy of Sciences (India)

    Mary Alex; V Balagi; K R Prasad; K P Sreekumar; P V Ananthapadmanabhan

    2000-11-01

    Conventional design of radiation detectors uses sintered ceramic insulating modules. The major drawback of these ceramic components is their inherent brittleness. Ion chambers, in which these ceramic spacers are replaced by metallic components with plasma spray coated alumina, have been developed in our Research Centre. These components act as thin spacers that have good mechanical strength as well as high electrical insulation and replace alumina insulators with the same dimensions. As a result, the design of the beam loss monitor ion chamber for CAT could be simplified by coating the outer surface of the HT electrode with alumina. One of the chambers developed for isotope calibrator for brachytherapy gamma sources has its outer aluminium electrode (60 mm dia × 220 mm long) coated with 250 thick alumina (97%) + titania (3%). In view of potential applications in neutron-sensitive ion chambers used in reactor control instrumentation, studies were carried out on alumina 100 to 500 thick coatings on copper, aluminium and SS components. The electrical insulation varied from 108 ohms to 1012 ohms for coating thicknesses above 200 . The porosity in the coating resulted in some fall in electrical insulation due to moisture absorption. An improvement could be achieved by providing the ceramic surface with moisture-repellent silicone oil coating. Irradiation at Apsara reactor core location showed that the coating on aluminium was found to be unaffected after exposure to 1017 nvt fluence.

  8. Use of Hansen Solubility Parameters in Fuel Treatment Processes

    Science.gov (United States)

    2014-03-17

    Charts 3. DATES COVERED (From - To) Jan 2014- Mar 2014 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER In-House Use of Hansen Solubility Parameters in...distribution is unlimited. AFRL Public Affairs Clearance # USE OF HANSEN SOLUBILITY PARAMETERS IN FUEL TREATMENT PROCESSES 17 March 2014 Andrew J...Treatment Needs – Hansen Solubility Parameters • Dyes – Experimental HSP Determination – Extrapolation to Other Dyes • Predictions for Extraction Fluids

  9. GA based CNC turning center exploitation process parameters optimization

    Directory of Open Access Journals (Sweden)

    Z. Car

    2009-01-01

    Full Text Available This paper presents machining parameters (turning process optimization based on the use of artificial intelligence. To obtain greater efficiency and productivity of the machine tool, optimal cutting parameters have to be obtained. In order to find optimal cutting parameters, the genetic algorithm (GA has been used as an optimal solution finder. Optimization has to yield minimum machining time and minimum production cost, while considering technological and material constrains.

  10. Process characteristics of fibre-laser-assisted plasma arc welding

    OpenAIRE

    Mahrle, A; SCHNICK, M; Rose, S; Demuth, C; Beyer, E.; Füssel, U

    2011-01-01

    Abstract Experimental and theoretical investigations on fibre-laser assisted plasma arc welding (LAPW) have been performed. Welding experiments were carried out on aluminium and steel sheets. In case of a highly focused laser beam and a separate arrangement of plasma torch and laser beam, high-speed video recordings of the plasma arc and corresponding measurements of the time-dependent arc voltage revealed differences in the process behaviour for both materials. In case of aluminium weldin...

  11. Effects of cigarette smoking on hemorheologic parameters, plasma osmolality and lung function.

    Science.gov (United States)

    Ergun, Dilek Duzgun; Karis, Denizhan; Alkan, Fatma Ates; Cakmak, Gulfidan; Yenigun, Mustafa; Ercan, Meltem

    2016-10-05

    Cigarette smoking deteriorates human health via vascular disorders, cancer and especially respiratory diseases. The aim of this study is to investigate effects of cigarette smoking on hemorheologic parameters, plasma osmolality and lung function in individuals without diagnosis of chronic obstructive pulmonary disease (COPD). Patients diagnosed without COPD utilizing respiratory function test were enrolled in the study with three groups, ex-smokers (n = 21), current-smokers (n = 35) and never-smokers (n = 43). Hemorheologic parameters and plasma osmolality were measured in hemorheology laboratory. SPSS 17.0 was used for statistical analysis. Blood and plasma viscosity, fibrinogen and hematocrit levels, mean corpuscular volume and mean corpuscular hemoglobin concentration were significantly elevated in ex-smokers and current-smokers compared to never-smokers. The standardized red blood cell deformability and oxygen delivery index and lung function were statistically lower in current-smokers than never-smokers. Pulmonary blood flow rate was statistically lower in current-smokers and ex-smokers than never-smokers. Plasma osmolality was statistically significantly higher in ex-smokers and current-smokers than never-smokers. Our findings clearly show that cigarette smoking has severe effects on hemorheologic parameters, plasma osmolality and lung function even in individuals without COPD. Blood and plasma viscosity with plasma osmolality might be useful markers to detect early hemorheologic-hemodynamic alterations in cigarette smokers.

  12. Laser initiation and decay processes in an organic vapor plasma

    Science.gov (United States)

    Ding, Guowen

    A large volume organic molecular plasma (hundreds of cm3) is created by a 193 nm laser ionizing an organic molecule, Tetrakis-(dimethylamino)-ethylene (TMAE). The plasma is found to be characterized by high electron density (10 13-1011cm-3), low electron temperature (~0.1 eV), fast creation (~10 ns) and rapid decaying (electron-ion recombination coefficient ~10-6 cm3/s). Fast Langmuir probe (LP) techniques are developed for diagnosing this plasma, including a novel probe design and fabrication, a fast detection system, sampling, indirect probe heating, electro-magnetic shielding and dummy probe techniques. Plasma physical processes regarding fast LP diagnostics for different time scales (t> and <100 ns) are studied. A theory for the correction due to a rapidly decaying plasma to LP measurements is developed. The mechanisms responsible for the plasma decay are studied, and a delayed ionization process is found to be important in interpreting the decay processes. It is also found that nitrogen can enhance the delayed emission of a TMAE Rydberg state from the TMAE plasma. This result strongly suggests that a long-lifetime highly-excited state is important in the TMAE plasma decay process. This result supports the delayed ionization mechanism. A model combining electron-ion recombination and delayed ionization processes is developed to calculate the delayed ionization lifetime.

  13. Use of cold plasma in food processing

    NARCIS (Netherlands)

    Mastwijk, H.C.; Nierop Groot, M.N.

    2010-01-01

    Application of cold plasma has been reported in agriculture, food, and bioscience literature as an effective, non-chemical, gas-phase disinfection agent that can be applied at moderate temperatures. The unusual thermodynamic properties of these gases are discussed with focus on nitrogen-based

  14. Parameter tuning of PVD process based on artificial intelligence technique

    Science.gov (United States)

    Norlina, M. S.; Diyana, M. S. Nor; Mazidah, P.; Rusop, M.

    2016-07-01

    In this study, an artificial intelligence technique is proposed to be implemented in the parameter tuning of a PVD process. Due to its previous adaptation in similar optimization problems, genetic algorithm (GA) is selected to optimize the parameter tuning of the RF magnetron sputtering process. The most optimized parameter combination obtained from GA's optimization result is expected to produce the desirable zinc oxide (ZnO) thin film from the sputtering process. The parameters involved in this study were RF power, deposition time and substrate temperature. The algorithm was tested to optimize the 25 datasets of parameter combinations. The results from the computational experiment were then compared with the actual result from the laboratory experiment. Based on the comparison, GA had shown that the algorithm was reliable to optimize the parameter combination before the parameter tuning could be done to the RF magnetron sputtering machine. In order to verify the result of GA, the algorithm was also been compared to other well known optimization algorithms, which were, particle swarm optimization (PSO) and gravitational search algorithm (GSA). The results had shown that GA was reliable in solving this RF magnetron sputtering process parameter tuning problem. GA had shown better accuracy in the optimization based on the fitness evaluation.

  15. Metal cutting analogy for establishing Friction Stir Welding process parameters

    Science.gov (United States)

    Stafford, Sylvester Allen

    A friction stir weld (FSW) is a solid state joining operation whose processing parameters are currently determined by lengthy trial and error methods. To implement FSWing rapidly in various applications will require an approach for predicting process parameters based on the physics of the process. Based on hot working conditions for metals, a kinematic model has been proposed for calculating the shear strain and shear strain rates during the FSW process, validation of the proposed model with direct measuring is difficult however. Since the shear strain and shear strain rates predicted for the FSW process, are similar to those predicted in metal cutting, validation of the FSW algorithms with microstructural studies of metal chips may be possible leading to the ability to predict FSW processing parameters.

  16. Plasma processing methods for hydrogen production

    Science.gov (United States)

    Mizeraczyk, Jerzy; Jasiński, Mariusz

    2016-08-01

    In the future a transfer from the fossil fuel-based economy to hydrogen-based economy is expected. Therefore the development of systems for efficient H2 production becomes important. The several conventional methods of mass-scale (or central) H2 production (methane, natural gas and higher hydrocarbons reforming, coal gasification reforming) are well developed and their costs of H2 production are acceptable. However, due to the H2 transport and storage problems the small-scale (distributed) technologies for H2 production are demanded. However, these new technologies have to meet the requirement of producing H2 at a production cost of (1-2)/kg(H2) (or 60 g(H2)/kWh) by 2020 (the U.S. Department of Energy's target). Recently several plasma methods have been proposed for the small-scale H2 production. The most promising plasmas for this purpose seems to be those generated by gliding, plasmatron and nozzle arcs, and microwave discharges. In this paper plasma methods proposed for H2 production are briefly described and critically evaluated from the view point of H2 production efficiency. The paper is aiming at answering a question if any plasma method for the small-scale H2 production approaches such challenges as the production energy yield of 60 g(H2)/kWh, high production rate, high reliability and low investment cost. Contribution to the topical issue "6th Central European Symposium on Plasma Chemistry (CESPC-6)", edited by Nicolas Gherardi, Ester Marotta and Cristina Paradisi

  17. Optimization of underwater wet welding process parameters using neural network

    National Research Council Canada - National Science Library

    Omajene, Joshua Emuejevoke; Martikainen, Jukka; Wu, Huapeng; Kah, Paul

    2014-01-01

    .... The soundness of a weld can be predicted from the weld bead geometry.This paper illustrates the application of artificial neural network approach in the optimization of the welding process parameter and the influence of the water environment...

  18. An experimental study on effect of process parameters in deep ...

    African Journals Online (AJOL)

    DR OKE

    Literature review reveals that the research on various aspects of modeling, simulation and process optimization of deep .... methodology is valuable only when the design parameters are qualitative and discrete. .... Work hardening exponent.

  19. Finding efficient frontier of process parameters for plastic injection molding

    National Research Council Canada - National Science Library

    Chen, Wu-Lin; Huang, Chin-Yin; Huang, Ching-Ya

    2013-01-01

    .... To find the settings for the process parameters such that the multiple quality indices can be simultaneously optimized is becoming a research issue and is now known as finding the efficient frontier...

  20. Towards predictive food process models: A protocol for parameter estimation.

    Science.gov (United States)

    Vilas, Carlos; Arias-Méndez, Ana; Garcia, Miriam R; Alonso, Antonio A; Balsa-Canto, E

    2016-05-31

    Mathematical models, in particular, physics-based models, are essential tools to food product and process design, optimization and control. The success of mathematical models relies on their predictive capabilities. However, describing physical, chemical and biological changes in food processing requires the values of some, typically unknown, parameters. Therefore, parameter estimation from experimental data is critical to achieving desired model predictive properties. This work takes a new look into the parameter estimation (or identification) problem in food process modeling. First, we examine common pitfalls such as lack of identifiability and multimodality. Second, we present the theoretical background of a parameter identification protocol intended to deal with those challenges. And, to finish, we illustrate the performance of the proposed protocol with an example related to the thermal processing of packaged foods.

  1. Synthesis of functional nanocrystallites through reactive thermal plasma processing

    Directory of Open Access Journals (Sweden)

    Takamasa Ishigaki and Ji-Guang Li

    2007-01-01

    Full Text Available A method of synthesizing functional nanostructured powders through reactive thermal plasma processing has been developed. The synthesis of nanosized titanium oxide powders was performed by the oxidation of solid and liquid precursors. Quench gases, either injected from the shoulder of the reactor or injected counter to the plasma plume from the bottom of the reactor, were used to vary the quench rate, and therefore the particle size, of the resultant powders. The experimental results are well supported by numerical analysis on the effects of the quench gas on the flow pattern and temperature field of the thermal plasma as well as on the trajectory and temperature history of the particles. The plasma-synthesized TiO2 nanoparticles showed phase preferences different from those synthesized by conventional wet-chemical processes. Nanosized particles of high crystallinity and nonequilibrium chemical composition were formed in one step via reactive thermal plasma processing.

  2. Automatic measurements of plasma parameters in the PUPR mirror and cusp plasma machine

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, S; Colmenares, F; Gonzalez-Lizardo, A; Leal-Quiros, E [Plasma Engineering Laboratory, Polytechnic University of Puerto Rico, San Juan, PR 00918 (Puerto Rico)

    2008-10-15

    This paper presents an ongoing effort to develop an automatic measurement system for plasma diagnostics at the Plasma Engineering Laboratory of the Polytechnic University of Puerto Rico (PUPR), along with an example of its operation. The system is intended to be used with electrostatic probes such as single and double Langmuir probes, emissive probes, ion and electron energy analyzers, etc. The automatic measurement system includes automatic positioning of the probes inside the plasma chamber, automatic voltage sweep of the probes for each position, and automatic analysis of the probe I-V characteristic. The results of measurements obtained by using this automatic measurement system during a particular experiment are shown and compared with a traditional method with satisfactory results.

  3. LIKELIHOOD ESTIMATION OF PARAMETERS USING SIMULTANEOUSLY MONITORED PROCESSES

    DEFF Research Database (Denmark)

    Friis-Hansen, Peter; Ditlevsen, Ove Dalager

    2004-01-01

    The topic is maximum likelihood inference from several simultaneously monitored response processes of a structure to obtain knowledge about the parameters of other not monitored but important response processes when the structure is subject to some Gaussian load field in space and time. The consi......The topic is maximum likelihood inference from several simultaneously monitored response processes of a structure to obtain knowledge about the parameters of other not monitored but important response processes when the structure is subject to some Gaussian load field in space and time....... The considered example is a ship sailing with a given speed through a Gaussian wave field....

  4. INVESTIGATION OF MODIFICATION PROCESSES IN RESPECT OF WEAR-RESISTANT PLASMA COATINGS USING PULSE-PLASMA MACHINING

    Directory of Open Access Journals (Sweden)

    V. A. Okovity

    2009-01-01

    Full Text Available The paper contains information on the investigated processes and optimized technological parameters  of  highly-energy  machining of plasma  coatings  made  of  cladding  composite  powders obtained as a result of self-spreading high-temperature synthesis. Metallographic analysis has been carried out and coating properties machined at optimum regimes have been investigated in the paper

  5. An approach for parameter estimation of biotechnological processes

    Energy Technology Data Exchange (ETDEWEB)

    Ljubenova, V. (Central Lab. of Bioinstrumentation and Automation, Bulgarian Academy of Sciences, Sofia (Bulgaria)); Ignatova, M.

    1994-08-01

    An approach for parameter estimators design of biotechnological processes (BTP) is presented in case of lack of real time information about state variables. It is based on general reaction rate models and measurements of at least one reaction rate. A general parameter estimator of BTP is designed with the help of which specific rate estimators are synthesized. Stability and convergence of an estimator of specific growth rate for a class of aerobic batch processes are proved. Its effectiveness is illustrated by simulation results. The proposed on-line parameter estimation approach can be used for design of BTP on-line variable estimation algorithms (variable observers of BTP). (orig.)

  6. Plasma Processing with Fluorine Chemistry for Modification of Surfaces Wettability

    Directory of Open Access Journals (Sweden)

    Veronica Satulu

    2016-12-01

    Full Text Available Using plasma in conjunction with fluorinated compounds is widely encountered in material processing. We discuss several plasma techniques for surface fluorination: deposition of fluorocarbon thin films either by magnetron sputtering of polytetrafluoroethylene targets, or by plasma-assisted chemical vapor deposition using tetrafluoroethane as a precursor, and modification of carbon nanowalls by plasma treatment in a sulphur hexafluoride environment. We showed that conformal fluorinated thin films can be obtained and, according to the initial surface properties, superhydrophobic surfaces can be achieved.

  7. Effect of magnetic barrier on the plasma parameters in a Trimix-M galatea

    Science.gov (United States)

    Morozov, A. I.; Bugrova, A. I.; Bishaev, A. M.; Lipatov, A. S.; Kozintseva, M. V.

    2006-11-01

    The parameters of plasma trapped in a Trimix-M galatea with increased values of the magnetic barrier and the energy of a hydrogen plasma bunch injected in the trap have been determined. For a barrier magnetic field of B b ˜ 0.1 T, the plasma confinement time in the trap is τp ≈ 300 μs (which agrees with estimates obtained using formulas describing the classical transfer), the maximum electron density is n e ˜ 5 × 1013 cm-3, and the electron and ion temperatures are T e ≈ 20 eV and T i ˜ 2T e, respectively. The energy of trapped plasma is ˜110 J, and the ratio of the gaskinetic to magnetic pressure in the plasma is β0 ˜ 0.2.

  8. Plasma Processing of Large Surfaces with Application to SRF Cavity Modification

    Energy Technology Data Exchange (ETDEWEB)

    Upadhyay, Janardan; Popovic, Svetozar; Vuskovic, Leposova; Im, Do; Valente, Anne-Marie; Phillips, H

    2013-09-01

    Plasma based surface modifications of SRF cavities present promising alternatives to the wet etching technology currently applied. To understand and characterize the plasma properties and chemical kinetics of plasma etching processes inside a single cell cavity, we have built a specially-designed cylindrical cavity with 8 observation ports. These ports can be used for holding niobium samples and diagnostic purposes simultaneously. Two frequencies (13.56 MHz and 2.45 GHz) of power source are used for different pressure, power and gas compositions. The plasma parameters were evaluated by a Langmuir probe and by an optical emission spectroscopy technique based on the relative intensity of two Ar 5p-4s lines at 419.8 and 420.07 nm. Argon 5p-4s transition is chosen to determine electron temperature in order to optimize parameters for plasma processing. Chemical kinetics of the process was observed using real-time mass spectroscopy. The effect of these parameters on niobium surface would be measured, presented at this conference, and used as guidelines for optimal design of SRF etching process.

  9. Plasma parameter characterization of a dc multicusp plasma chamber operating in He, Ar and Xe gas

    Energy Technology Data Exchange (ETDEWEB)

    Suanpoot, Pradoong; Vilaithong, Thiraphat; Boonyawan, Dheerawan [Fast Neutron Research Facility, Dept. of Physics, Faculty of Science, Chiang Mai Univ. (Thailand); Rhodes, M.W.

    1998-12-31

    A large dc multicusp plasma chamber has been constructed and installed at Chiang Mai University. The first prototype has a 31.2 cm diameter and a 42.5 cm length and is surrounded by 632 ceramic permanent magnet buttons with a maximum magnetic field of about 2.2 kG for each. The magnetic field at the stainless steel wall with a thickness of 2 mm is about 670 G. A tungsten (W) filament was used as a source of primary electrons. The estimated discharge voltage for helium gas (He), argon gas (Ar), and xenon gas (Xe) was 40 V and the discharge operating current varies from 500 mA to 1 A. Plasmas can be confined within a 20 cm diameter region which are uniformly distributed along the axial path. The plasma density was measured by a single cylindrical Langmuir probe to be between 4.8 x 10{sup 8} - 4.9 x 10{sup 9} cm{sup -3} with 650 watts of power applied to the tungsten filament and the gas pressure inside the chamber of 3.8 x 10{sup -4} Torr. Results of the ion density measurements are described. The proportionality constants in the relation between the ion current density arriving at the plasma electrode and the maximum plasma density and the ion sound speed for helium, argon and xenon are found to be 0.42 {+-} 0.07, 0.59 {+-} 0.08, and 0.46 {+-} 0.06, respectively. (author)

  10. Variation of plasma parameters of vacuum arc column with gap distance

    Science.gov (United States)

    Han, Wen; Yuan, Zhao; He, Junjia

    2016-07-01

    On the basis of a two-dimensional (2D) magneto-hydrodynamic model, we studied long-gap-distance vacuum arcs in a uniform axial magnetic field and determined the effect of gap distance varying in a large range on plasma parameters. Simulation results showed that with increasing gap distance, the parameters of the plasma near the cathode are almost invariant, except for ion number density, but the parameters of the plasma in front of the anode clearly vary; meanwhile, joule heat gradually becomes the main source of energy for the arc column. In a short gap, a clear current constriction can be found in the entire arc column. Whereas when the gap distance exceeds a certain value, a sharp contraction of the current only arises in front of the anode.

  11. Numerical simulation of nonlinear processes in a beam-plasma system

    Energy Technology Data Exchange (ETDEWEB)

    Efimova, A. A., E-mail: anna.an.efimova@gmail.com; Berendeev, E. A.; Vshivkov, V. A. [Institute of Computational Mathematics and Mathematical Geophysics SB RAS 6 Acad. Lavrentyev Ave., Novosibirsk 630090 (Russian Federation); Dudnikova, G. I. [University of Maryland, College Park, MD 20742 (United States); Institute of Computational Technologies SB RAS, 6 Acad. Lavrentyev Ave., Novosibirsk 630090 (Russian Federation)

    2015-10-28

    In the present paper we consider the efficiency of the electromagnetic radiation generation due to various nonlinear processes in the beam-plasma system. The beam and plasma parameters were chosen close to the parameters in the experiment on the GOL-3 facility (BINP SB RAS). The model of the collisionless plasma is described by system of the Vlasov-Maxwell equations with periodic boundary conditions. The parallel numerical algorithm is based on the particles-in-cell method (PIC) with mixed Euler-Lagrangian domain decomposition. Various scenarios of nonlinear evolution in the beam-plasma system under the influence of an external magnetic field in case of a low density beam were studied. The energy transfer from one unstable mode to the others modes was observed.

  12. Internal oscillating current-sustained RF plasmas: Parameters, stability, and potential for surface engineering

    DEFF Research Database (Denmark)

    Ostrikov, K.; Tsakadze, E.L.; Tsakadze, Z.L.;

    2005-01-01

    plasma parameters by the optical and Langmuir probes are presented. It is shown that the spatial profiles of the electron density, the effective electron temperature and plasma potential feature a great deal of the radial and axial uniformity compared with conventional sources of inductively coupled......A new source of low-frequency (0.46 MHz) inductively coupled plasmas sustained by the internal planar "unidirectional" RF current driven through a specially designed internal antenna configuration has been developed. The experimental results of the investigation of the optical and global argon...... applications and surface engineering. (c) 2005 Elsevier B.V. All rights reserved....

  13. Ni/Al Intermetallics Plasma Transferred Arc Processing

    Institute of Scientific and Technical Information of China (English)

    VeronicaA.B.Almeida; AnaSofiaC.M.D'Oliveira

    2004-01-01

    In-situ alloy development during surface processing allows for a limitless materials selection to protect components exposed to severe service conditions. In fact surface alloying offers the possibility to strengthen surface components with alloys that would not be possible to process otherwise. This work used Plasma transferred arc (PTA) hardfacing for surface alloying. Different amounts of aluminium powder, 5-25%, were added to a Ni based superalloy, from Hastealloy C family, in the atomized form. The mixture was homogeneized in a ball mill and PTA deposited on carbon steel substrate. The influence of different processing parameters on the final surface alloy was evaluated as current intensity and depositing velocity were varied. Coatings were characterized by optical and scanning electronic microscopy, X-ray diffraction and Vickers microhardness profiles, under a 500g load. Results showed that PTA hardfacing is an adequate surface alloying. For the conditions tested increasing hardness was obtained by solid solution for the lower amounts of Al added and due to the new intermetallic phases for the richer Al mixture.

  14. Ni/Al Intermetallics Plasma Transferred Arc Processing

    Institute of Scientific and Technical Information of China (English)

    Ver(o)nica A. B. Almeida; Ana Sofia C. M. D'Oliveira

    2004-01-01

    In-situ alloy development during surface processing allows for a limitless materials selection to protect components exposed to severe service conditions. In fact surface alloying offers the possibility to strengthen surface components with alloys that would not be possible to process otherwise. This work used Plasma transferred arc (PTA) hardfacing for surface alloying. Different amounts of aluminium powder, 5-25%, were added to a Ni based superalloy, from Hastealloy C family, in the atomized form. The mixture was homogeneized in a ball mill and PTA deposited on carbon steel substrate. The influence of different processing parameters on the final surface alloy was evaluated as current intensity and depositing velocity were varied. Coatings were characterized by optical and scanning electronic microscopy, X-ray diffraction and Vickers microhardness profiles, under a 500g load. Results showed that PTA hardfacing is an adequate surface alloying. For the conditions tested increasing hardness was obtained by solid solution for the lower amounts of Al added and due to the new intermetallic phases for the richer Al mixture.

  15. Fluorophore-based sensor for oxygen radicals in processing plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Choudhury, Faraz A.; Shohet, J. Leon, E-mail: shohet@engr.wisc.edu [Plasma Processing and Technology Laboratory and Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Sabat, Grzegorz; Sussman, Michael R. [Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Nishi, Yoshio [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States)

    2015-11-15

    A high concentration of radicals is present in many processing plasmas, which affects the processing conditions and the properties of materials exposed to the plasma. Determining the types and concentrations of free radicals present in the plasma is critical in order to determine their effects on the materials being processed. Current methods for detecting free radicals in a plasma require multiple expensive and bulky instruments, complex setups, and often, modifications to the plasma reactor. This work presents a simple technique that detects reactive-oxygen radicals incident on a surface from a plasma. The measurements are made using a fluorophore dye that is commonly used in biological and cellular systems for assay labeling in liquids. Using fluorometric analysis, it was found that the fluorophore reacts with oxygen radicals incident from the plasma, which is indicated by degradation of its fluorescence. As plasma power was increased, the quenching of the fluorescence significantly increased. Both immobilized and nonimmobilized fluorophore dyes were used and the results indicate that both states function effectively under vacuum conditions. The reaction mechanism is very similar to that of the liquid dye.

  16. Method and system for nanoscale plasma processing of objects

    Science.gov (United States)

    Oehrlein, Gottlieb S.; Hua, Xuefeng; Stolz, Christian

    2008-12-30

    A plasma processing system includes a source of plasma, a substrate and a shutter positioned in close proximity to the substrate. The substrate/shutter relative disposition is changed for precise control of substrate/plasma interaction. This way, the substrate interacts only with a fully established, stable plasma for short times required for nanoscale processing of materials. The shutter includes an opening of a predetermined width, and preferably is patterned to form an array of slits with dimensions that are smaller than the Debye screening length. This enables control of the substrate/plasma interaction time while avoiding the ion bombardment of the substrate in an undesirable fashion. The relative disposition between the shutter and the substrate can be made either by moving the shutter or by moving the substrate.

  17. Apparatus and method for plasma processing of SRF cavities

    CERN Document Server

    Upadhyay, J; Peshl, J; Bašović, M; Popović, S; Valente-Feliciano, A -M; Phillips, L; Vuškovića, L

    2015-01-01

    An apparatus and a method are described for plasma etching of the inner surface of superconducting radio frequency (SRF) cavities. Accelerator SRF cavities are formed into a variable-diameter cylindrical structure made of bulk niobium, for resonant generation of the particle accelerating field. The etch rate non-uniformity due to depletion of the radicals has been overcome by the simultaneous movement of the gas flow inlet and the inner electrode. An effective shape of the inner electrode to reduce the plasma asymmetry for the coaxial cylindrical rf plasma reactor is determined and implemented in the cavity processing method. The processing was accomplished by moving axially the inner electrode and the gas flow inlet in a step-wise way to establish segmented plasma columns. The test structure was a pillbox cavity made of steel of similar dimension to the standard SRF cavity. This was adopted to experimentally verify the plasma surface reaction on cylindrical structures with variable diameter using the segment...

  18. Radiant-and-plasma technology for coal processing

    Directory of Open Access Journals (Sweden)

    Vladimir Messerle

    2012-12-01

    Full Text Available Radiant-and-plasma technology for coal processing is presented in the article. Thermodynamic computation and experiments on plasma processing of bituminous coal preliminary electron-beam activated were fulfilled in comparison with plasma processing of the coal. Positive influence of the preliminary electron-beam activation of coal on synthesis gas yield was found. Experiments were carried out in the plasma gasifier of 100 kW power. As a result of the measurements of material and heat balance of the process gave the following integral indicators: weight-average temperature of 2200-2300 K, and carbon gasification degree of 82,4-83,2%. Synthesis gas yield at thermochemical preparation of raw coal dust for burning was 24,5% and in the case of electron-beam activation of coal synthesis gas yield reached 36,4%, which is 48% higher.

  19. SOME COLLISION PROCESSES IN PLASMAS WITH HIGHER TEMPERATURE AND DENSITY

    Institute of Scientific and Technical Information of China (English)

    KazuoTakayanagi

    1990-01-01

    Some collision processes important in hot and dense plasmas are discussed.Recent calculation of secondary electron velocity distribution in ionizing collision between an electron and a multiply-charged ion is reported.

  20. Reactive Atom Plasma Processing of Slumped Glass Wedges Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Reactive Atom Plasma (RAPTM) process will be evaluated as a rapid and practical method for fabricating precision wedges in glass sheets. The glass sheets are to...

  1. Selection of parameters for advanced machining processes using firefly algorithm

    Directory of Open Access Journals (Sweden)

    Rajkamal Shukla

    2017-02-01

    Full Text Available Advanced machining processes (AMPs are widely utilized in industries for machining complex geometries and intricate profiles. In this paper, two significant processes such as electric discharge machining (EDM and abrasive water jet machining (AWJM are considered to get the optimum values of responses for the given range of process parameters. The firefly algorithm (FA is attempted to the considered processes to obtain optimized parameters and the results obtained are compared with the results given by previous researchers. The variation of process parameters with respect to the responses are plotted to confirm the optimum results obtained using FA. In EDM process, the performance parameter “MRR” is increased from 159.70 gm/min to 181.6723 gm/min, while “Ra” and “REWR” are decreased from 6.21 μm to 3.6767 μm and 6.21% to 6.324 × 10−5% respectively. In AWJM process, the value of the “kerf” and “Ra” are decreased from 0.858 mm to 0.3704 mm and 5.41 mm to 4.443 mm respectively. In both the processes, the obtained results show a significant improvement in the responses.

  2. Spray drying technique. I: Hardware and process parameters.

    Science.gov (United States)

    Cal, Krzysztof; Sollohub, Krzysztof

    2010-02-01

    Spray drying is a transformation of feed from a fluid state into a dried particulate form by spraying the feed into a hot drying medium. The main aim of drying by this method in pharmaceutical technology is to obtain dry particles with desired properties. This review presents the hardware and process parameters that affect the properties of the dried product. The atomization devices, drying chambers, air-droplet contact systems, the collection of dried product, auxiliary devices, the conduct of the spray drying process, and the significance of the individual parameters in the drying process, as well as the obtained product, are described and discussed.

  3. Uniform dimension results of multi-parameter stable processes

    Institute of Scientific and Technical Information of China (English)

    林火南

    1999-01-01

    The problem of uniform dimensions for multi-parameter processes, which may not possess the uniform stochastic H(?)lder condition, is investigated. The problem of uniform dimension for multi-parameter stable processes is solved. That is, if Z is a stable (N, d, α)-process and αN≤d, then (?)E(?)R_+~N, dimZ(E)=α·dimE holds with probability 1, where Z(E)={x:(?)t∈E, Z_t=x} is the image set of Z on E. The uniform upper bounds for multi-parameter processes with independent increments under general conditions are also given. Most conclusions about uniform dimension can be considered as special cases of our results.

  4. Time dependent atomic processes in discharge produced low Z plasma

    Science.gov (United States)

    Yuyama, M.; Sasaki, T.; Horioka, K.; Kawamura, T.

    2008-05-01

    The z-pinch simulation have been performed with magneto-hydro dynamics and atomic population kinetics codes. A factor associated with transient atomic processes was proposed. The atomic transient degrees of dopant lithium in hydrogen plasma were calculated with initial plasma densities of 1.0 × 1016 ~ 5.0 × 1017cm-3. The higher initial plasma density is, the lower is the transient degree generally. It is also found that the transient properties of the atomic processes are sensitive to ionization energy and electron temperature.

  5. Global parameter optimization of Mather type plasma focus in the framework of the Gratton-Vargas two-dimensional snowplow model

    CERN Document Server

    Auluck, S K H

    2014-01-01

    Dense Plasma Focus (DPF) is known to produce highly energetic ions, electrons and plasma environment which can be used for breeding of short-lived isotopes, plasma nanotechnology and other material processing applications. Commercial utilization of DPF in such areas would need a design tool which can be deployed in an automatic search for the best possible device configuration for a given application. The recently revisited [S K H Auluck, Physics of Plasmas 20, 112501 (2013)] Gratton-Vargas (GV) two-dimensional analytical snowplow model of plasma focus provides a numerical formula for dynamic inductance of a Mather type plasma focus fitted to thousands of automated computations, which enables construction of such design tool. This inductance formula is utilized in the present work to explore global optimization, based on first-principles optimality criteria, in a 4-dimensional parameter-subspace of the zero-resistance GV model. The optimization process is shown to reproduce the empirically observed constancy ...

  6. Prediction of Electrochemical Machining Process Parameters using Artificial Neural Networks

    Directory of Open Access Journals (Sweden)

    Hoda Hosny Abuzied

    2012-01-01

    Full Text Available Electrochemical machining (ECM is a non-traditional machining process used mainly to cut hard or difficult to cut metals, where the application of a more traditional process is not convenient. It offers several special advantages including higher machining rate, better precision and control, and a wider range of materials that can be machined. A suitable selection of machining parameters for the ECM process relies heavily on the operator’s technologies and experience because of their numerous and diverse range. Machining parameters provided by the machine tool builder cannot meet the operator’s requirements. So, artificial neural networks were introduced as an efficient approach to predict the values of resulting surface roughness and material removal rate. Many researchers usedartificial neural networks (ANN in improvement of ECM process and also in other nontraditional machining processes as well be seen in later sections. The present study is, initiated to predict values of some of resulting process parameters such as metal removal rate(MRR, and surface roughness (Ra using artificial neural networks based on variation of certain predominant parameters of an electrochemical broaching process such as applied voltage, feed rate and electrolyte flow rate. ANN was found to be an efficient approach as it reduced time & effort required to predict material removal rate & surface roughness if they were found experimentally using trial & error method. To validate the proposed approach the predicted values of surface roughness and material removal rate were compared with a previously obtained ones from the experimental work.

  7. Initial damage processes for diamond film exposure to hydrogen plasma

    Energy Technology Data Exchange (ETDEWEB)

    Deslandes, A., E-mail: acd@ansto.gov.au [Institute for Environmental Research, Australian Nuclear Science and Technology Organisation, Sydney (Australia); Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, Sydney (Australia); Guenette, M.C. [Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, Sydney (Australia); Samuell, C.M. [Plasma Research Laboratory, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia); Karatchevtseva, I. [Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, Sydney (Australia); Ionescu, M.; Cohen, D.D. [Institute for Environmental Research, Australian Nuclear Science and Technology Organisation, Sydney (Australia); Blackwell, B. [Plasma Research Laboratory, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia); Corr, C., E-mail: cormac.corr@anu.edu.au [Plasma Research Laboratory, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia); Riley, D.P., E-mail: dry@ansto.gov.au [Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, Sydney (Australia)

    2013-12-15

    Graphical abstract: -- Highlights: • Exposing chemical vapour deposited (CVD) diamond films in a recently constructed device, MAGPIE, specially commissioned to simulate fusion plasma conditions. • Non-diamond material is etched from the diamond. • There is no hydrogen retention observed, which suggests diamond is an excellent candidate for plasma facing materials. • Final structure of the surface is dependent on synergistic effects of etching and ion-induced structural change. -- Abstract: Diamond is considered to be a possible alternative to other carbon based materials as a plasma facing material in nuclear fusion devices due to its high thermal conductivity and resistance to chemical erosion. In this work CVD diamond films were exposed to hydrogen plasma in the MAGnetized Plasma Interaction Experiment (MAGPIE): a linear plasma device at the Australian National University which simulates plasma conditions relevant to nuclear fusion. Various negative sample stage biases of magnitude less than 500 V were applied to control the energies of impinging ions. Characterisation results from SEM, Raman spectroscopy and ERDA are presented. No measureable quantity of hydrogen retention was observed, this is either due to no incorporation of hydrogen into the diamond structure or due to initial incorporation as a hydrocarbon followed by subsequent etching back into the plasma. A model is presented for the initial stages of diamond erosion in fusion relevant hydrogen plasma that involves chemical erosion of non-diamond material from the surface by hydrogen radicals and damage to the subsurface region from energetic hydrogen ions. These results show that the initial damage processes in this plasma regime are comparable to previous studies of the fundamental processes as reported for less extreme plasma such as in the development of diamond films.

  8. Learning the Parameters of Determinantal Point Process Kernels

    OpenAIRE

    Affandi, Raja Hafiz; Fox, Emily; Adams, Ryan Prescott; Taskar, Ben

    2014-01-01

    Determinantal point processes (DPPs) are well-suited for modeling repulsion and have proven useful in many applications where diversity is desired. While DPPs have many appealing properties, such as efficient sampling, learning the parameters of a DPP is still considered a difficult problem due to the non-convex nature of the likelihood function. In this paper, we propose using Bayesian methods to learn the DPP kernel parameters. These methods are applicable in large-scale and continuous DPP ...

  9. What can we learn about HiPIMS process from the multidimensional plasma modeling?

    Science.gov (United States)

    Minea, Tiberiu

    2016-09-01

    The modeling of PVD process and especially magnetron plasma is widely reported. The novel way to excite the plasma applying to the cathode very high power pulses brings the temporal dimension to the system together with new phenomena. From the kinetic model of the dense plasma region, so called Ionization Region - IR, one can quantify the global behavior of the plasma parameters during the pulse. The most significant are the plasma composition, especially in the case of reactive gases, the fraction of back-attracted sputtered ions, the rarefaction due to wind effect, but also the discharge heating mechanisms and contribution to the discharge current. From the 2D particle modeling of the plasma new insights are revealed concerning the shape of the dense plasma region, the time evolution of the sheath, the electron energy distribution function, but also the characteristics of the diffusion plasma facing the substrate. Adding the third dimension to the model, the results reveal the complex transport of electrons especially in the azimuthal direction (instabilities and drifts), the formation of spokes and flares, and the strong relation between the secondary emission of electrons from the target and the plasma structuring. Warm thanks to Peter Awakowicz and Ante Hecimovic for inviting me to this GEC edition.

  10. Real-Time Fault Classification for Plasma Processes

    Directory of Open Access Journals (Sweden)

    Ryan Yang

    2011-07-01

    Full Text Available Plasma process tools, which usually cost several millions of US dollars, are often used in the semiconductor fabrication etching process. If the plasma process is halted due to some process fault, the productivity will be reduced and the cost will increase. In order to maximize the product/wafer yield and tool productivity, a timely and effective fault process detection is required in a plasma reactor. The classification of fault events can help the users to quickly identify fault processes, and thus can save downtime of the plasma tool. In this work, optical emission spectroscopy (OES is employed as the metrology sensor for in-situ process monitoring. Splitting into twelve different match rates by spectrum bands, the matching rate indicator in our previous work (Yang, R.; Chen, R.S. Sensors 2010, 10, 5703-5723 is used to detect the fault process. Based on the match data, a real-time classification of plasma faults is achieved by a novel method, developed in this study. Experiments were conducted to validate the novel fault classification. From the experimental results, we may conclude that the proposed method is feasible inasmuch that the overall accuracy rate of the classification for fault event shifts is 27 out of 28 or about 96.4% in success.

  11. Real-time fault classification for plasma processes.

    Science.gov (United States)

    Yang, Ryan; Chen, Rongshun

    2011-01-01

    Plasma process tools, which usually cost several millions of US dollars, are often used in the semiconductor fabrication etching process. If the plasma process is halted due to some process fault, the productivity will be reduced and the cost will increase. In order to maximize the product/wafer yield and tool productivity, a timely and effective fault process detection is required in a plasma reactor. The classification of fault events can help the users to quickly identify fault processes, and thus can save downtime of the plasma tool. In this work, optical emission spectroscopy (OES) is employed as the metrology sensor for in-situ process monitoring. Splitting into twelve different match rates by spectrum bands, the matching rate indicator in our previous work (Yang, R.; Chen, R.S. Sensors 2010, 10, 5703-5723) is used to detect the fault process. Based on the match data, a real-time classification of plasma faults is achieved by a novel method, developed in this study. Experiments were conducted to validate the novel fault classification. From the experimental results, we may conclude that the proposed method is feasible inasmuch that the overall accuracy rate of the classification for fault event shifts is 27 out of 28 or about 96.4% in success.

  12. Impact of processing parameters on the LTCC channels geometry*

    Directory of Open Access Journals (Sweden)

    Macioszczyk Jan

    2015-12-01

    Full Text Available A great advantage of Low Temperature Co-fired Ceramics (LTCC yields the possibility of channel and air cavity fabrication. Such empty spaces have numerous applications, for example, in microfluidics, microwave techniques and integrated packaging. However, improper geometry of these structures can degrade the performance of the final device. The processing parameters recommended by the LTCC tape supplier are relevant for the production of multilayer circuits but not surface embedded channels and/or cavities. Thus, it is important to examine which factors of the fabrication process are the most significant. In our study, special attention has been paid to the geometric performance of the channel structure resulting from the applied processing parameters. Laser cutting parameters were checked to obtain the structures with great fidelity. The impact of an isostatic lamination on the quality of the final structure was analyzed. The influence of pressure and temperature of the lamination process on the channel geometry and tape shrinkage were examined. The performed experiments showed that some improvements in channel/cavity geometry may be achieved by optimizing the processing procedures. The microscopic observations combined with the Analysis of Variance (ANOVA showed which combinations of the processing parameters are the best for achieving a channel/cavity structure with the desired geometry.

  13. Proceedings of the international seminar on atomic processes in plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Takako; Murakami, Izumi [eds.

    2000-01-01

    The International Seminar on Atomic Processes in Plasmas (ISAPP), a satellite meeting to the ICPEAC was held July 28-29 at the National Institute for Fusion Science in Toki, Gifu, Japan. About 110 scientists attended the ISAPP meeting and discussed atomic processes and atomic data required for fusion research. This Proceedings book includes the papers of the talks, posters and panel discussion given at the meeting. The invited talks described the super configuration array method for complex spectra, near-LTE atomic kinetics, R-matrix calculations, the binary-encounter dipole model for electron-impact ionization of molecules, other calculations of molecular processes, the ADAS project and the NIFS atomic data-base, and a survey of the role of molecular processes in divertor plasmas. On the experimental side crossed-beam ion-ion collision-experiments for charge transfer, and storage-ring and EBIT measurements of ionization, excitation and dielectronic recombination cross-sections were presented, and atomic processes important for x-ray laser experiments and x-ray spectroscopy of astrophysical plasmas were described. The new method of plasma polarization spectroscopy was outlined. There was also a spectroscopic study of particle transport in JT-60U, new results for detached plasmas, and a sketch of the first hot plasma experiments with the Large Helical Device recently completed at NIFS. The 63 of the presented papers are indexed individually. (J.P.N.)

  14. Spectroscopic diagnostics of plasma during laser processing of aluminium

    Science.gov (United States)

    Lober, R.; Mazumder, J.

    2007-10-01

    The role of the plasma in laser-metal interaction is of considerable interest due to its influence in the energy transfer mechanism in industrial laser materials processing. A 10 kW CO2 laser was used to study its interaction with aluminium under an argon environment. The objective was to determine the absorption and refraction of the laser beam through the plasma during the processing of aluminium. Laser processing of aluminium is becoming an important topic for many industries, including the automobile industry. The spectroscopic relative line to continuum method was used to determine the electron temperature distribution within the plasma by investigating the 4158 Å Ar I line emission and the continuum adjacent to it. The plasmas are induced in 1.0 atm pure Ar environment over a translating Al target, using f/7 and 10 kW CO2 laser. Spectroscopic data indicated that the plasma composition and behaviour were Ar-dominated. Experimental results indicated the plasma core temperature to be 14 000-15 300 K over the incident range of laser powers investigated from 5 to 7 kW. It was found that 7.5-29% of the incident laser power was absorbed by the plasma. Cross-section analysis of the melt pools from the Al samples revealed the absence of any key-hole formation and confirmed that the energy transfer mechanism in the targets was conduction dominated for the reported range of experimental data.

  15. Bioactive Glass-Ceramic Coatings Synthesized by the Liquid Precursor Plasma Spraying Process

    Science.gov (United States)

    Xiao, Yanfeng; Song, Lei; Liu, Xiaoguang; Huang, Yi; Huang, Tao; Chen, Jiyong; Wu, Yao; Wu, Fang

    2011-03-01

    In this study, the liquid precursor plasma spraying process was used to manufacture P2O5-Na2O-CaO-SiO2 bioactive glass-ceramic coatings (BGCCs), where sol and suspension were used as feedstocks for plasma spraying. The effect of precursor and spray parameters on the formation and crystallinity of BGCCs was systematically studied. The results indicated that coatings with higher crystallinity were obtained using the sol precursor, while nanostructured coatings predominantly consisting of amorphous phase were synthesized using the suspension precursor. For coatings manufactured from suspension, the fraction of the amorphous phase increased with the increase in plasma power and the decrease in liquid precursor feed rate. The coatings synthesized from the suspension plasma spray process also showed a good in vitro bioactivity, as suggested by the fast apatite formation when soaking into SBF.

  16. Thomson Scattering Process in Laser-Produced Plasmas

    Institute of Scientific and Technical Information of China (English)

    YU Quan-Zhi; JIANG Xiao-Hua; LI Wen-Hong; LIU Shen-Ye; ZHENG Zhi-Jian; ZHANG Jie; LI Yu-Tong; ZHENG Jun; YAN Fei; LU Xin; WANG Zhe-Bin; ZHENG Jian; YU Chang-Xuan

    2005-01-01

    @@ We present the evolutions of the electron temperature and plasma expansion velocity with Thomson scattering experiment. The observed time-resolved ion-acoustic image is reproduced by a numerical code which couples the Thomson scattering theory with the output parameters of the one-dimensional hydrocode MEDUSA.

  17. Optimization of Gas Metal Arc Welding Process Parameters

    Science.gov (United States)

    Kumar, Amit; Khurana, M. K.; Yadav, Pradeep K.

    2016-09-01

    This study presents the application of Taguchi method combined with grey relational analysis to optimize the process parameters of gas metal arc welding (GMAW) of AISI 1020 carbon steels for multiple quality characteristics (bead width, bead height, weld penetration and heat affected zone). An orthogonal array of L9 has been implemented to fabrication of joints. The experiments have been conducted according to the combination of voltage (V), current (A) and welding speed (Ws). The results revealed that the welding speed is most significant process parameter. By analyzing the grey relational grades, optimal parameters are obtained and significant factors are known using ANOVA analysis. The welding parameters such as speed, welding current and voltage have been optimized for material AISI 1020 using GMAW process. To fortify the robustness of experimental design, a confirmation test was performed at selected optimal process parameter setting. Observations from this method may be useful for automotive sub-assemblies, shipbuilding and vessel fabricators and operators to obtain optimal welding conditions.

  18. Diagnostics of recombining laser plasma parameters based on He-like ion resonance lines intensity ratios

    Science.gov (United States)

    Ryazantsev, S. N.; Skobelev, I. Yu; Faenov, A. Ya; Pikuz, T. A.; Grum-Grzhimailo, A. N.; Pikuz, S. A.

    2016-11-01

    While the plasma created by powerful laser expands from the target surface it becomes overcooled, i.e. recombining one. Improving of diagnostic methods applicable for such plasma is rather important problem in laboratory astrophysics nowadays because laser produced jets are fully scalable to young stellar objects. Such scaling is possible because of the plasma hydrodynamic equations invariance under some transformations. In this paper it is shown that relative intensities of the resonance transitions in He-like ions can be used to measure the parameters of recombining plasma. Intensity of the spectral lines corresponding to these transitions is sensitive to the density in the range of 1016-1020 cm-3 while the temperature ranges from 10 to 100 eV for ions with nuclear charge Zn ∼ 10. Calculations were carried out for F VIII ion and allowed to determine parameters of plasma jets created by nanosecond laser system ELFIE (Ecole Polytechnique, France) for astrophysical phenomenon modelling. Obtained dependencies are quite universal and can be used for any recombining plasma containing He-like fluorine ions.

  19. Characteristics and plasma parameters of a short-wavelength low-pressure discharge lamp

    Science.gov (United States)

    Shuaibov, A. K.; Shevera, I. V.; Malinina, A. A.

    2008-10-01

    We have studied the working optical characteristics and electron kinetic coefficients of a short-wavelength, electric discharge exciplex-halogen UV-VUV lamp employing a mixture of argon and chlorine with a total pressure of P = 0.5 10 kPa. The lamp operates on a system of broadened electron-vibrational bands of ArCl (175 nm) and chlorine (200, 258 nm) molecules, which overlap to form a continuum in the spectral range of 160 260 nm. It is established that the optimum mixtures are those with p(Ar) - p(Cl2) = (2 4)-(0.15 0.30) kPa. The average output power of the short-wavelength radiation is 1 2 W at an efficiency of ˜5%. The electron energy distribution functions (EDFs) and the discharge plasma parameters have been calculated by solving the Boltzmann equation for a gas mixture with the experimentally determined optimum composition in the range of E/ P values from 1 to 200 V/(cm Torr), where E is the electric field strength and P is the total gas pressure. Using the obtained EDFs, the electron transport characteristics, specific discharge power losses for the main elementary processes, and rate constants of electron processes are determined.

  20. Parameter Study of Plasma-Induced Atmospheric Sputtering and Heating at Mars

    Science.gov (United States)

    Williamson, Hayley N.; Johnson, Robert E.; Leblanc, Francois

    2014-11-01

    Atoms and molecules in Mars’ upper atmosphere are lost predominately through sputtering, caused by the impact of ions into the exosphere, dissociative recombination, and thermal escape. While all three processes are thought to occur on Mars, a detailed understanding must ascertain the relative importance of each process, due to time variations in pick-up and solar wind ions. In this project, using case studies of an oxygen atmosphere modeled with Direct Simulation Monte Carlo techniques, we have endeavored to categorize when the momentum transfer or thermal escape is more likely to occur. To do this, we vary the incident plasma flux and energy based on models of the interaction of the solar wind with the Martian atmosphere. We first repeat the heating and sputtering rates due to a flux of pick-up O+ examined previously (Johnson et al. 2000; Michael and Johnson 2005; Johnson et al 2013). We have used multiple examples of particle fluxes for various solar wind conditions, from steady solar wind conditions (Luhmann et al. 1992; Chaufray et al. 2007) to more extreme cases (Fang et al. 2013; Wang et al. 2014), which are thought to increase escape by several orders of magnitude. The goal is to explore the escape parameter space in preparation for the expected data from MAVEN on hot atoms and molecules in the Martian exosphere.

  1. Measurements of egg shell plasma parameters using laser-induced breakdown spectroscopy

    Indian Academy of Sciences (India)

    Wenfeng Luo; Xiaoxia Zhao; Shuyuan Lv; Haiyan Zhu

    2015-07-01

    Measurements of 1064 nm laser-induced egg shell plasma parameters are presented in this paper. Of special interests were its elemental identification and the determination of spectroscopic temperature and electron density. The electron temperature of 5956 K was inferred using an improved iterative Boltzmann plot method with six calcium atomic emission lines, and the electron number density of 6.1 × 1016 cm−3 was determined by measuring the width of Stark-broadened once-ionized calcium line at 393.37 nm. Based on the experimental results, the laser-induced egg shell plasma was verified to be optically thin and satisfy local thermodynamic equilibrium (LTE). Furthermore, experiments also demonstrated that the loss of energy due to the reflection of the laser beam from the plasma can be neglected and the inverse bremsstrahlung (IB) absorption was the dominant mechanism of plasma heating at the IR wavelength.

  2. Lindhard's polarization parameter and atomic sum rules in the local plasma approximation

    DEFF Research Database (Denmark)

    Cabrera-Trujillo, R.; Apell, P.; Oddershede, J.

    2017-01-01

    In this work, we analyze the effects of Lindhard polarization parameter, χ, on the sum rule, Sp, within the local plasma approximation (LPA) as well as on the logarithmic sum rule Lp = dSp/dp, in both cases for the system in an initial excited state. We show results for a hydrogenic atom with nuc...

  3. Measurement Of Plasma Parameters In Micro-Discharge By Wall Probe

    Science.gov (United States)

    Saifutdinov, Almaz; Kudryavtsev, Anatoly; Sysoev, Sergey

    2016-09-01

    The increasing scientific and practical interest for glow discharge at high pressure is largely determined by the fact that their use does not require expensive and huge vacuum equipment. The analysis shows that, in contrast to the well-studied positive column (PC), the basic parameters of the plasma negative glow (NG) and Faraday dark space (FDS) of micro-discharges are studied insufficiently. The difficulties of the experimental diagnostics are associated with the fact that for the fixed values of pL with the increasing gas pressure the length of the micro-discharge decreases. And a small size is extremely difficult to diagnose spatial parameters distribution of micro discharges. Since at a small size introducing traditional Langmuir probe into the plasma capacity is not possible technically, it was proposed to use an additional measuring electrode (wall probe) disposed between the cathode and the anode for measurement of the fast EEDF. With its use we have registered EEDF fast electrons produced in the reaction of Penning ionization out of earlier reach range of high-pressure gas (from 20 to 200 Torr). In this paper by using wall probe we measured the basic parameters of NG plasma in micro-discharge in helium in a wide range of pressures. It is shown that the electrons temperature in the NG plasma is low and amounts to few fraction of 1 eV, which differs from the electron temperature in PC plasma. This allows the use of NG plasma for analysis by gas plasma electron spectroscopy. Authors thanks RNF (Grant 14-19-00311) for the support.

  4. Investigation of Normalization Methods using Plasma Parameters for Laser Induced Breakdown Spectroscopy (LIBS) under simulated Martian Conditions

    OpenAIRE

    Vogt, David; Schröder, Susanne; Hübers, H.-W.

    2017-01-01

    Laser Induced Breakdown Spectroscopy data need to be normalized, especially in the field of planetary exploration We investigated plasma parameters as temperature and electron density for this purpose.

  5. Linear and Nonlinear MHD Wave Processes in Plasmas. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Tataronis, J. A.

    2004-06-01

    This program treats theoretically low frequency linear and nonlinear wave processes in magnetized plasmas. A primary objective has been to evaluate the effectiveness of MHD waves to heat plasma and drive current in toroidal configurations. The research covers the following topics: (1) the existence and properties of the MHD continua in plasma equilibria without spatial symmetry; (2) low frequency nonresonant current drive and nonlinear Alfven wave effects; and (3) nonlinear electron acceleration by rf and random plasma waves. Results have contributed to the fundamental knowledge base of MHD activity in symmetric and asymmetric toroidal plasmas. Among the accomplishments of this research effort, the following are highlighted: Identification of the MHD continuum mode singularities in toroidal geometry. Derivation of a third order ordinary differential equation that governs nonlinear current drive in the singular layers of the Alfvkn continuum modes in axisymmetric toroidal geometry. Bounded solutions of this ODE implies a net average current parallel to the toroidal equilibrium magnetic field. Discovery of a new unstable continuum of the linearized MHD equation in axially periodic circular plasma cylinders with shear and incompressibility. This continuum, which we named “accumulation continuum” and which is related to ballooning modes, arises as discrete unstable eigenfrequency accumulate on the imaginary frequency axis in the limit of large mode numbers. Development of techniques to control nonlinear electron acceleration through the action of multiple coherent and random plasmas waves. Two important elements of this program aye student participation and student training in plasma theory.

  6. Decay parameter and related properties of 2-type branching processes

    Institute of Scientific and Technical Information of China (English)

    LI JunPing

    2009-01-01

    We consider the decay parameter, invariant measures/vectors and quasi-stationary dis-tributions for 2-type Markov branching processes. Investigating such properties is crucial in realizing life period of branching models. In this paper, some important properties of the generating functions for 2-type Markov branching q-matrix are firstly investigated in detail. The exact value of the decay parameter λC of such model is given for the communicating class C = Z+2\\ 0. It is shown that this λC can be directly obtained from the generating functions of the corresponding q-matrix. Moreover, the λC-invariant measures/vectors and quasi-distributions of such processes are deeply considered. A λC-invariant vector for the q-matrix (or for the process) on C is given and the generating functions of λC-invariant measures and quasi-stationary distributions for the process on C are presented.

  7. Decay parameter and related properties of 2-type branching processes

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    We consider the decay parameter, invariant measures/vectors and quasi-stationary dis- tributions for 2-type Markov branching processes. Investigating such properties is crucial in realizing life period of branching models. In this paper, some important properties of the generating functions for 2-type Markov branching q-matrix are firstly investigated in detail. The exact value of the decay parameter λC of such model is given for the communicating class C = Z+2 \\ 0. It is shown that this λC can be directly obtained from the generating functions of the corresponding q-matrix. Moreover, the λC-invariant measures/vectors and quasi-distributions of such processes are deeply considered. A λC-invariant vector for the q-matrix (or for the process) on C is given and the generating functions of λC-invariant measures and quasi-stationary distributions for the process on C are presented.

  8. Impact of Modal Parameters on Milling Process Chatter Stability Lobes

    Institute of Scientific and Technical Information of China (English)

    LI Zhongqun; LIU Qiang

    2006-01-01

    Modals of the machine/tool and machine/part system are the principal factors affecting the stability of a milling process. Based on the modeling of chatter stability of milling process, the influence of modal parameters on chatter stability lobes independently or jointly has been analyzed by simulation. Peak-to-valley specific value, lobe coefficient and the corresponding calculation formula have been put forward. General laws and steps of modal simplification for multimodality system have been summarized.

  9. Influence of argon fraction on plasma parameters in H2-N2 mixture discharge with cathodic cage

    Science.gov (United States)

    Naeem, Muhammad; Zaka-ul-Islam, Mujahid; Khattak, Zahid Iqbal; Shafiq, Muhammad; Zakaullah, Muhammad

    2017-01-01

    Low-pressure H2-N2 mixture pulsed DC plasmas with a cathodic cage (active screen) are widely used for plasma nitriding applications. In this study, the low-pressure H2-N2 mixture plasma with a cathodic cage generated by 50 Hz pulsed DC source is investigated with triple Langmuir probe and optical emission spectroscopy. The electron temperature (TeLP T e LP ) and electron number density (ne) are measured using a triple Langmuir probe (TLP). The excitation temperature (TexcOES T e xc OES ) is calculated spectroscopically using Boltzmann plot method whereas nitrogen dissociation fraction is estimated using actinometry as well as the intensity ratio method (IN (746.83 nm)/IN2(337.1 nm)). The results show that the electron and excitation temperatures, electron density and nitrogen atomic species density [N] all increase with the argon admixture, however, the important molecular ionized species density [N2+ N 2 + ] significantly decreases beyond 30% addition. This study provides useful information about the influence of the argon addition on plasma parameters and active species generation. As a result it helps to optimize the plasma nitriding system as a function of argon admixture to avoid random trials in the processing.

  10. Determination of SATI Instrument Filter Parameters by Processing Interference Images

    CERN Document Server

    Atanassov, Atanas Marinov

    2010-01-01

    This paper presents a method for determination of interference filter parameters such as the effective refraction index and the maximal transmittance wavelength on the basis of image processing of a spectrogram produced by Spectrometer Airglow Temperature Imager instrument by means of data processing. The method employs the radial sections for determination of points from the crests and valleys in the spectrograms. These points are involved in the least square method for determination of the centres and radii of the crests and valleys. The use of the image radial sections allows to determine the maximal number of crests and valleys in the spectrogram. The application of the least square fitting leads to determination of the image centers and radii of the crests and valleys with precision higher than one pixel. The nocturnal course of the filter parameters produced by this method is presented and compared with that of the known ones. The values of the filter parameters thus obtained are closer to the laborator...

  11. Local times of N-parameter Gaussian processes

    Institute of Scientific and Technical Information of China (English)

    LIN Zhengyan; CHENG Zongmao

    2005-01-01

    An N-parameter Gaussian stationary process X = { X ( t ): t ∈ RN+ } is introduced and the existence and joint continuity of its local times is presented. And the moments of local times are estimated. Furthermore moduli of continuity and large increment results for the local times are established.

  12. The effect of degeneracy parameter on Weibel instability in dense plasma

    Energy Technology Data Exchange (ETDEWEB)

    Mahdavi, M. [Physics Department, Mazandaran University, P.O. Box 47415-416 Babolsar (Iran, Islamic Republic of); Khodadadi Azadboni, F. [Physics Department, Mazandaran University, P.O. Box 47415-416 Babolsar (Iran, Islamic Republic of); Young Researchers Club, Sari Branch, Islamic Azad University, P.O. Box 48161-194 Sari (Iran, Islamic Republic of)

    2013-12-15

    In this paper, the role of degeneracy parameter, in both directions parallel and perpendicular with propagation direction of the laser beam in plasma, on the growth rate of Weibel instability, is studied. Calculations show that with the temperature anisotropy, β = T{sub ∥}/T{sub ⊥} = 0.2 and a 0.75 times reduction of the degeneracy parameter, the increased rate of the the Weibel instability growth rate is 72%. The degeneracy required for minimal growth rate in interaction laser plasma with a density of 1.2 × 10{sup 32}m{sup −3}, is larger than 3. The reduction of temperature and the degeneracy parameter of plasma in parallel direction will also increase growth rate about 30% more than incrossing degeneracy parameter in transverse direction. With the minimum pressure costs of cold compression, subsequent degeneracy parameters, and the minimum value of electron quiver energy, we can expect growth rate of Weibel instability order 0.01.

  13. Modelling of the arc reattachment process in plasma torches

    Energy Technology Data Exchange (ETDEWEB)

    Trelles, J P; Pfender, E; Heberlein, J V R [Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455 (United States)

    2007-09-21

    The need to improve plasma spraying processes has motivated the development of computational models capable of describing the arc dynamics inside plasma torches. Although progress has been made in the development of such models, the realistic simulation of the arc reattachment process, a central part of the arc dynamics inside plasma torches, is still an unsolved problem. This study presents a reattachment model capable of mimicking the physical reattachment process as part of a local thermodynamic equilibrium description of the plasma flow. The fluid and electromagnetic equations describing the plasma flow are solved in a fully-coupled approach by a variational multi-scale finite element method, which implicitly accounts for the multi-scale nature of the flow. The effectiveness of our modelling approach is demonstrated by simulations of a commercial plasma spraying torch operating with Ar-He under different operating conditions. The model is able to match the experimentally measured peak frequencies of the voltage signal, arc lengths and anode spot sizes, but produces voltage drops exceeding those measured. This finding, added to the apparent lack of a well-defined cold boundary layer all around the arc, points towards the importance of non-equilibrium effects inside the torch, especially in the anode attachment region.

  14. A Course on Plasma Processing in Integrated Circuit Fabrication.

    Science.gov (United States)

    Sawin, Herbert H.; Reif, Rafael

    1983-01-01

    Describes a course, taught jointly by electrical/chemical engineering departments at the Massachusetts Institute of Technology, designed to teach the fundamental science of plasma processing as well as to give an overview of the present state of industrial processes. Provides rationale for course development, texts used, class composition, and…

  15. Deep silicon etch for biology MEMS fabrication: review of process parameters influence versus chip design

    Science.gov (United States)

    Magis, T.; Ballerand, S.; Bellemin Comte, A.; Pollet, Olivier

    2013-03-01

    Micro-system for biology is a growing market, especially for micro-fluidic applications (environment and health). Key part for the manufacturing of biology MEMS is the deep silicon etching by plasma to create microstructures. Usual etching process as an alternation of etching and passivation steps is a well-known method for MEMS fabrication, nowadays used in high volume production for devices like sensors and actuators. MEMS for biology applications are very different in design compared to more common micro-systems like accelerometers for instance. Indeed, their design includes on the same chip structures of very diverse size like narrow pillars, large trenches and wide cavities. This makes biology MEMS fabrication very challenging for DRIE, since each type of feature considered individually would require a specific etch process. Furthermore process parameters suited to match specifications on small size features (vertical profile, low sidewall roughness) induce issues and defects on bigger structures (undercut, micro-masking) and vice versa. Thus the process window is constrained leading to trade-offs in process development. In this paper process parameters such as source and platen powers, pressure, etching and passivation gas flows and steps duration were investigated to achieve all requirements. As well interactions between those different factors were characterized at different levels, from individual critical feature up to chip scale and to wafer scale. We will show the plasma process development and tuning to reach all these specifications. We also compared different chambers configurations of our ICP tool (source wafer distance, plasma diffusion) in order to obtain a good combination of hardware and process. With optimized etching we successfully fabricate micro-fluidic devices like micro-pumps.

  16. Atomic and molecular processes in JT-60U divertor plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Takenaga, H.; Shimizu, K.; Itami, K. [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment] [and others

    1997-01-01

    Atomic and molecular data are indispensable for the understanding of the divertor characteristics, because behavior of particles in the divertor plasma is closely related to the atomic and molecular processes. In the divertor configuration, heat and particles escaping from the main plasma flow onto the divertor plate along the magnetic field lines. In the divertor region, helium ash must be effectively exhausted, and radiation must be enhanced for the reduction of the heat load onto the divertor plate. In order to exhaust helium ash effectively, the difference between behavior of neutral hydrogen (including deuterium and tritium) and helium in the divertor plasma should be understood. Radiation from the divertor plasma generally caused by the impurities which produced by the erosion of the divertor plate and/or injected by gas-puffing. Therefore, it is important to understand impurity behavior in the divertor plasma. The ions hitting the divertor plate recycle through the processes of neutralization, reflection, absorption and desorption at the divertor plates and molecular dissociation, charge-exchange reaction and ionization in the divertor plasma. Behavior of hydrogen, helium and impurities in the divertor plasmas can not be understood without the atomic and molecular data. In this report, recent results of the divertor study related to the atomic and molecular processes in JT-60U were summarized. Behavior of neural deuterium and helium was discussed in section 2. In section 3, the comparisons between the modelling of the carbon impurity transport and the measurements of C II and C IV were discussed. In section 4, characteristics of the radiative divertor using Ne puffing were reported. The new diagnostic method for the electron density and temperature in the divertor plasmas using the intensity ratios of He I lines was described in section 5. (author)

  17. The optimization of operating parameters on microalgae upscaling process planning.

    Science.gov (United States)

    Ma, Yu-An; Huang, Hsin-Fu; Yu, Chung-Chyi

    2016-03-01

    The upscaling process planning developed in this study primarily involved optimizing operating parameters, i.e., dilution ratios, during process designs. Minimal variable cost was used as an indicator for selecting the optimal combination of dilution ratios. The upper and lower mean confidence intervals obtained from the actual cultured cell density data were used as the final cell density stability indicator after the operating parameters or dilution ratios were selected. The process planning method and results were demonstrated through three case studies of batch culture simulation. They are (1) final objective cell densities were adjusted, (2) high and low light intensities were used for intermediate-scale cultures, and (3) the number of culture days was expressed as integers for the intermediate-scale culture.

  18. Synchronous pulsing plasma utilization in dummy poly gate removal process

    Science.gov (United States)

    Huang, Ruixuan; Meng, Xiao-Ying; Han, Qiu-Hua; Zhang, Hai-Yang

    2015-03-01

    When CMOS technology reaches 28/20nm node and beyond, several new schemes are implemented such as High K metal gate (HKMG) which can enhance the device performance and has better control of device current leakage. Dummy poly gate removal (DPGR) process is introduced for HKMG, and works as a key process to control the work function of metal gate and threshold voltage (Vt) shift. In dry etch technology, conventional continuous wave (CW) plasma process has been widely used, however, it may not be capable for some challenging process in 28nm node and beyond. In DPGR process for HKMG scheme, CW scheme may result in plasma damage of gate oxide/capping layer for its inherent high electron temperature (Te) and ion energy while synchronous pulsing scheme is capable to simultaneously pulse both source and bias power, which could achieve lower Te, independent control of ion and radical flux, well control the loading of polymer deposition on dense/ isolate features. It's the first attempt to utilize synchronous pulsing plasma in DPGR process. Experiment results indicate that synchronous pulsing could provide less silicon recess under thin gate oxide which is induced by the plasma oxidation. Furthermore, the loading of HK capping layer loss between long channel and short channel can be well controlled which plays a key role on transistor performance, such as leakage and threshold voltage shift. Additionally, it has been found that synchronous pulsing could distinctly improve ILD loss when compared with CW, which is helpful to broaden the whole process window.

  19. Process Parameters Optimization in Single Point Incremental Forming

    Science.gov (United States)

    Gulati, Vishal; Aryal, Ashmin; Katyal, Puneet; Goswami, Amitesh

    2016-04-01

    This work aims to optimize the formability and surface roughness of parts formed by the single-point incremental forming process for an Aluminium-6063 alloy. The tests are based on Taguchi's L18 orthogonal array selected on the basis of DOF. The tests have been carried out on vertical machining center (DMC70V); using CAD/CAM software (SolidWorks V5/MasterCAM). Two levels of tool radius, three levels of sheet thickness, step size, tool rotational speed, feed rate and lubrication have been considered as the input process parameters. Wall angle and surface roughness have been considered process responses. The influential process parameters for the formability and surface roughness have been identified with the help of statistical tool (response table, main effect plot and ANOVA). The parameter that has the utmost influence on formability and surface roughness is lubrication. In the case of formability, lubrication followed by the tool rotational speed, feed rate, sheet thickness, step size and tool radius have the influence in descending order. Whereas in surface roughness, lubrication followed by feed rate, step size, tool radius, sheet thickness and tool rotational speed have the influence in descending order. The predicted optimal values for the wall angle and surface roughness are found to be 88.29° and 1.03225 µm. The confirmation experiments were conducted thrice and the value of wall angle and surface roughness were found to be 85.76° and 1.15 µm respectively.

  20. RILL EROSION PROCESS AND RILL FLOW HYDRAULIC PARAMETERS

    Institute of Scientific and Technical Information of China (English)

    Fen-li ZHENG; Pei-qing XIAO; Xue-tian GAO

    2004-01-01

    In the rill erosion process,run-on water and sediment from upslope areas,and rill flow hydraulic parameters have significant effects on sediment detachment and transport.However,there is a lack of data to quantify the effects of run-on water and sediment and rill flow hydraulic parameters on rill erosion process at steep hillslopes,especially in the Loess Plateau of China.A dual-box system,consisting of a 2-m-long feeder box and a 5-m-long test box with 26.8% slope gradient was used to quantify the effects of upslope runoff and sediment,and of rill flow hydraulic parameters on the rill erosion process.The results showed that detachment-transport was dominated in rill erosion processes; upslope runoff always caused the net rill detachment at the downslope rill flow channel,and the net rill detachment caused by upslope runoff increased with a decrease of runoff sediment concentration from the feeder box or an increase of rainfall intensity.Upslope runoff discharging into the rill flow channel or an increase of rainfall intensity caused the rill flow to shift from a stratum flow into a turbulent flow.Upslope runoff had an important effect on rill flow hydraulic parameters,such as rill flow velocity,hydraulic radius,Reynolds number,Froude number and the Darcy-Weisbach resistance coefficient.The net rill detachment caused by upslope runoff increased as the relative increments of rill flow velocity,Reynolds number and Froude number caused by upslope runoff increased.In contrast,the net rill detachment decreased with an increase of the relative decrement of the Darcy-Weisbach resistance coefficient caused by upslope runoff.These findings will help to improve the understanding of the effects of run-on water and sediment on the erosion process and to find control strategies to minimize the impact of run-on water.

  1. Numerical simulation of chemical processes in atmospheric plasmas

    Institute of Scientific and Technical Information of China (English)

    Ouyang Jian-Ming; Guo Wei; Wang Long; Shao Fu-Qiu

    2004-01-01

    A model is built to study chemical processes in atmospheric plasmas at low altitude (high pressure) and at high altitude (low pressure). The plasma lifetime and the temporal evolution of the main charged species are presented.The electron number density does not strictly obey the exponential damping law in a long period. The heavy charged species are dominant at low altitude in comparison with the light species at high altitude. Some species of small amount in natural air play an important role in the processes.

  2. Evaluation of control parameters of the activated sludge process

    Energy Technology Data Exchange (ETDEWEB)

    Stall, T.R.; Sherrard, J.H.

    1978-03-01

    The evaluation of control parameters of the activated sludge process was effected with a laboratory-scale, completely mixed process employing internal cell recycle and an artificial wasterwater over a wide spectrum of conditions at full-scale facilities. The parameters: food-microorganism ratio, specific utilization rate, COD or BOD sludge age, and aeration and total system mean cell residence time can all be used to control an activated sludge wastewater treatment plant. Because of the sensitivity of the COD or BOD sludge age (when compared with measures of mean cell residence time), its use may be of limited value. The aeration basin cell residence time may be favored over the total system mean cell residence time because of the ease in measuring aeration basin solids and the difficulty in measuring solids concentration at the bottom of the secondary clarifier and in the recycle line.

  3. From pulsed power to processing: Plasma initiated chemical process intensification

    NARCIS (Netherlands)

    Heesch, E.J.M. van; Yan, K.; Pemen, A.J.M.; Winands, G.J.J.; Beckers, F.J.C.M.; Hoeben, W.F.L.M.

    2012-01-01

    Smart electric power for process intensification is a challenging research field that integrates power engineering, chemistry and green technology. Pulsed power technology is offering elegant solutions. This work focuses on backgrounds of matching the power source to the process. Important items are

  4. Dynamics of electronegative plasmas for materials processing. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Lichtenberg, A.J.; Lieberman, M.A.

    1996-12-31

    Purpose was to study equilibrium particle and energy balance and heating mechanisms in electronegative rf discharges. Attention is given to formation of non-Maxwellian electron distributions and their effect on macroscopic parameters. Research includes theory, particle- in-cell simulation, and experimental investigations. Sheath heating theory and simulation results for electropositive plasmas are used as guide. The investigation was centered on, but not limited to, study of oxygen feedstock gas in capacitively and inductively coupled rf discharges.

  5. Estimation of the Processing Parameters in Electron Beam Thermal Treatments

    Directory of Open Access Journals (Sweden)

    DULAU Mircea

    2014-05-01

    Full Text Available Electron beam have many special properties which make them particularly well suited for use in materials handling through melting, welding, surface treatment, etc., taking into account that this manufacturing is performed in vacuum. The use of electron beam for surface limited heat treatment of workpiece has brought about a noticeable extension of the beam technologies. Some theoretical aspects and simulation results are presented in this paper, considering a high power electron beam processing system and Matlab facilities. This paper can be used in power engineering and electro-technologies fields as a guideline, in order to simulate and analyse the process parameters.

  6. Optimization of vibratory welding process parameters using response surface methodology

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Pravin Kumar; Kumar, S. Deepak; Patel, D.; Prasad, S. B. [National Institute of Technology Jamshedpur, Jharkhand (India)

    2017-05-15

    The current investigation was carried out to study the effect of vibratory welding technique on mechanical properties of 6 mm thick butt welded mild steel plates. A new concept of vibratory welding technique has been designed and developed which is capable to transfer vibrations, having resonance frequency of 300 Hz, into the molten weld pool before it solidifies during the Shielded metal arc welding (SMAW) process. The important process parameters of vibratory welding technique namely welding current, welding speed and frequency of the vibrations induced in molten weld pool were optimized using Taguchi’s analysis and Response surface methodology (RSM). The effect of process parameters on tensile strength and hardness were evaluated using optimization techniques. Applying RSM, the effect of vibratory welding parameters on tensile strength and hardness were obtained through two separate regression equations. Results showed that, the most influencing factor for the desired tensile strength and hardness is frequency at its resonance value, i.e. 300 Hz. The micro-hardness and microstructures of the vibratory welded joints were studied in detail and compared with those of conventional SMAW joints. Comparatively, uniform and fine grain structure has been found in vibratory welded joints.

  7. Parameters Optimization of Low Carbon Low Alloy Steel Annealing Process

    Institute of Scientific and Technical Information of China (English)

    Maoyu ZHAO; Qianwang CHEN

    2013-01-01

    A suitable match of annealing process parameters is critical for obtaining the fine microstructure of material.Low carbon low alloy steel (20CrMnTi) was heated for various durations near Ac temperature to obtain fine pearlite and ferrite grains.Annealing temperature and time were used as independent variables,and material property data were acquired by orthogonal experiment design under intercritical process followed by subcritical annealing process (IPSAP).The weights of plasticity (hardness,yield strength,section shrinkage and elongation) of annealed material were calculated by analytic hierarchy process,and then the process parameters were optimized by the grey theory system.The results observed by SEM images show that microstructure of optimization annealing material are consisted of smaller lamellar pearlites (ferrite-cementite)and refining ferrites which distribute uniformly.Morphologies on tension fracture surface of optimized annealing material indicate that the numbers of dimple fracture show more finer toughness obviously comparing with other annealing materials.Moreover,the yield strength value of optimization annealing material decreases apparently by tensile test.Thus,the new optimized strategy is accurate and feasible.

  8. 14th High-Tech Plasma Processes Conference (HTPP 14)

    Science.gov (United States)

    2017-04-01

    Preface The High-Tech Plasma Processes Conference (HTPP) is a bi-annual international conference based in Europe with topics encompassing the whole area of plasma processing science. This conference is open to all the international community in the world involved in plasma science and plasma technology. The aim of the conference is to bring different scientific communities together, facilitate the contacts between science, technology and industry and provide a platform for the exploration of both fundamental topics and new applications of plasmas. For this edition of HTPP, as was the case for the last, we have achieved a well balanced participation from the communities of both thermal and non-thermal plasma researchers. 75 people from 17 countries attended the conference with the total number of contributions being 74, consisting of 19 invited talks and 55 poster contributions. As a HTPP tradition a poster competition has been carried out during the conference. The winner of the poster competition was Fabrice Mavier from Université de Limoges, France with his paper “Pulsed arc plasma jet synchronized with drop-on-demand dispenser” All the participants also ejoyed the social program including an “unconventional” tour of the city, the visit to the famous Hofbräuhaus and the dinner at the Blutenburg, a beautiful inner-city castle. We have received papers corresponding to the contributions of HTPP-2014 that have been submitted for publication in this volume of Journal of Physics: Conference Series. Each submitted contribution has been peer reviewed and the Editors are very grateful to the referees for their careful support in improving the original manuscripts. In total, 18 manuscripts have been accepted for publication covering a range of topics of plasma processing science from plasma fundamentals to process applications through to experiments, diagnostics and modelling. We deeply thank the authors for their enthusiastic and high-grade contributions and we

  9. Simulation of polyatomic discharges for thin film deposition processes in low-pressure plasma reactors

    Science.gov (United States)

    Bera, Kallol

    conditions of experimental reactors. The discharge models were used to investigate the effects of operating and design parameters of the reactors on plasma process characteristics to obtain better process characteristics on the wafer. These parameters can be used to design new reactors for the deposition/etching process. The models can be modified for different feed gases for other applications like plasma etching or sputtering.

  10. The possible role of hydrogen sulfide as a modulator of hemostatic parameters of plasma.

    Science.gov (United States)

    Olas, Beata; Kontek, Bogdan

    2014-09-05

    Hydrogen sulfide (H2S) is a well known toxic gas at high levels. However, at physiological levels, H2S may play a role in the pathogenesis of various cardiovascular diseases. The objective was to study the effects of exogenous H2S on the hemostatic parameters (coagulation and fibrinolytic activity) of human plasma. Human plasma was incubated (5, 15 and 30 min) with NaHS as a H2S donor at the final concentration of 0.01-100 μM. Hemostatic factors, such as maximum velocity of clot formation, fibrin lysis half-time, the activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT) were estimated. Moreover, the aim of our study was to establish the influence of NaHS (10 μM; 5, 15 and 30 min) on the clot formation using the purified fibrinogen. We demonstrated that coagulation/fibrinolytic properties of human plasma incubated with NaHS were changed. APPT, PT and TT of plasma treated with NaHS at tested concentrations--0.01-100 μM were prolonged. We observed that NaHS (0.01-100 μM) reduced fibrin polymerization in whole plasma and 10 μM NaHS also reduced polymerization of purified fibrinogen. In the presence of NaHS (at the low tested concentration--1 μM) the decrease was about 18% (in plasma, p<0.05). Our experiments also showed that NaHS (0.01-100 μM) stimulated the fibrin lysis in whole plasma. However, the time-dependent (5, 15 and 30 min) reduction of fibrin/fibrinogen polymerization and stimulation of fibrin lysis by NaHS (10 μM) was not observed. In conclusion, the present study demonstrates the anticoagulant properties of exogenous H2S in vitro.

  11. Influence of renormalization shielding on the electron-impact ionization process in dense partially ionized plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Song, Mi-Young; Yoon, Jung-Sik [Plasma Technology Research Center, National Fusion Research Institute, 814-2 Osikdo-Dong, Gunsan-City, Jeollabuk-Do 573-540 (Korea, Republic of); Jung, Young-Dae, E-mail: ydjung@hanyang.ac.kr [Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180-3590 (United States); Department of Applied Physics and Department of Bionanotechnology, Hanyang University, Ansan, Kyunggi-Do 426-791 (Korea, Republic of)

    2015-04-15

    The renormalization shielding effects on the electron-impact ionization of hydrogen atom are investigated in dense partially ionized plasmas. The effective projectile-target interaction Hamiltonian and the semiclassical trajectory method are employed to obtain the transition amplitude as well as the ionization probability as functions of the impact parameter, the collision energy, and the renormalization parameter. It is found that the renormalization shielding effect suppresses the transition amplitude for the electron-impact ionization process in dense partially ionized plasmas. It is also found that the renormalization effect suppresses the differential ionization cross section in the peak impact parameter region. In addition, it is found that the influence of renormalization shielding on the ionization cross section decreases with an increase of the relative collision energy. The variations of the renormalization shielding effects on the electron-impact ionization cross section are also discussed.

  12. On the iodine doping process of plasma polymerised thiophene layers

    NARCIS (Netherlands)

    Groenewoud, L.M.H.; Engbers, G.H.M.; White, R.; Feijen, Jan

    2002-01-01

    To make a fair comparison of the conductive properties of plasma polymerised thiophene (PPT) layers deposited under different conditions, optimal doping procedures should be applied. The iodine doping process of PPT layers deposited at high (HP) and low (LP) pressure has been studied in detail.

  13. Cold plasma as a nonthermal food processing technology

    Science.gov (United States)

    Contamination of meats, seafood, poultry, eggs, and fresh and fresh-cut fruits and vegetables is an ongoing concern. Although well-established in non-food applications for surface treatment and modification, cold plasma is a relatively new food safety intervention. As a nonthermal food processing te...

  14. Electron beam generated plasmas for the processing of graphene

    Science.gov (United States)

    Walton, S. G.; Hernández, S. C.; Boris, D. R.; Petrova, Tz B.; Petrov, G. M.

    2017-09-01

    The Naval Research Laboratory (NRL) has developed a processing system based on an electron beam-generated plasma and applied it to the processing of graphene. Unlike conventional discharges produced by electric fields (DC, RF, microwave, etc), the plasma is driven by a high-energy (~few keV) electron beam, an approach that simplifies the relative production of species while providing comparatively high ion-to-radical production rates. The resulting plasmas are characterized by high charged particle densities (1010-1011 cm-3) and electron temperatures that are typically about 1.0 eV or lower. Accordingly, the flux to adjacent surfaces is generally dominated by ions with kinetic energies in the range of 1-5 eV, a value at or near the bond strength of most materials. This provides the potential for controllably engineering materials with monolayer precision, an attribute attractive for the processing of atomically thin material systems. This work describes the attributes of electron beam driven plasma processing system and its use in modification of graphene.

  15. On the iodine doping process of plasma polymerised thiophene layers

    NARCIS (Netherlands)

    Groenewoud, L.M.H.; Engbers, G.H.M.; White, R.; Feijen, J.

    2001-01-01

    To make a fair comparison of the conductive properties of plasma polymerised thiophene (PPT) layers deposited under different conditions, optimal doping procedures should be applied. The iodine doping process of PPT layers deposited at high (HP) and low (LP) pressure has been studied in detail. Dopi

  16. Electroacoustic Process Study of Plasma Sparker Under Different Water Depth

    KAUST Repository

    Huang, Yifan

    2015-01-05

    The plasma sparker has been applied in oceanic high-resolution seismic exploration for decades. Normally it is towed on the water surface. This is suitable for shallow water, but if the water depth is great, the resolution will decrease dramatically, especially in the horizontal direction. This paper proposes the concept of a deep-towed plasma sparker and presents an experimental study of plasma sparker performance in terms of electric parameters, bubble behavior, and acoustic characteristics. The results show that hydrostatic pressure at a source depth ranging from 1 to 2000 m has a negligible influence on the electric parameters but a strong influence on bubble behavior, wherein both the maximum bubble radius and oscillation period are decreased. The collapse pulse vanishes when the source depth reaches 1000 m or deeper, and no bubble oscillation can be distinguished. The source level (evaluated by the expansion pulse) is also decreased as the source depth increases; moreover, the greater the discharge energy, the smaller the source level loss. The discharge energy per electrode should be greater than 20 J for the deep-towed plasma sparker, which can make the source level loss induced by hydrostatic pressure smaller than the transmission loss. The fast Fourier transform (FFT) results show that the dominant energy is around 20 kHz, which is mainly induced by the expansion pulse and its oscillation. According to the simulation results, the fundamental frequency of the acoustic waveform increases with source depth in accord with a log linear trend, and also reaches tens of kilohertz in deep water. So, before the development of deep-towed plasma sparker, a new technical solution will need to be developed to solve this problem. © 1976-2012 IEEE.

  17. Global parameter optimization of a Mather-type plasma focus in the framework of the Gratton-Vargas two-dimensional snowplow model

    Science.gov (United States)

    Auluck, S. K. H.

    2014-12-01

    Dense plasma focus (DPF) is known to produce highly energetic ions, electrons and plasma environment which can be used for breeding short-lived isotopes, plasma nanotechnology and other material processing applications. Commercial utilization of DPF in such areas would need a design tool that can be deployed in an automatic search for the best possible device configuration for a given application. The recently revisited (Auluck 2013 Phys. Plasmas 20 112501) Gratton-Vargas (GV) two-dimensional analytical snowplow model of plasma focus provides a numerical formula for dynamic inductance of a Mather-type plasma focus fitted to thousands of automated computations, which enables the construction of such a design tool. This inductance formula is utilized in the present work to explore global optimization, based on first-principles optimality criteria, in a four-dimensional parameter-subspace of the zero-resistance GV model. The optimization process is shown to reproduce the empirically observed constancy of the drive parameter over eight decades in capacitor bank energy. The optimized geometry of plasma focus normalized to the anode radius is shown to be independent of voltage, while the optimized anode radius is shown to be related to capacitor bank inductance.

  18. Preparation of ion-exchange thin film using plasma processes. Plasma process wo mochiita ion kokansei usumaku no sakusei

    Energy Technology Data Exchange (ETDEWEB)

    Ogumi, Z.; Uchimoto, Y. (Kyoto University, Kyoto (Japan). Faculty of Engineering)

    1992-10-31

    The present report describes a study which aims at preparation of a new functional film by plasma polymerization. For this purpose, 4-vinylpyridine monomer is plasma-polymerized to obtain a thin film, which is quaternarized with 1-bromopropane to produce an anion exchange thin film, which is laminated on the surface of a cation-exchange film to make a mono-valent cation perm-selective film. In plasma-polymerization, the relations of polymerizing pressure, as parameter, to the deposition rate of the polymerizerd film and the characteristics of compound were clarified. In preparing the anion-exchange thin film, the preparation of uniform ultrathin films with no pinhole was attempted. For this purpose, the transference number of Cl[sup -] was measured so as to confirm that Cl[sup -] is uniformly distributed and fixed cation groups are distributed uniformly in the film. The perm-selective film exhibited a high mono-valent cation perm-selectivity while its film resistance was increased. This increase is found to be broken down to the resistance of the plasma-polymerization film layer and the resistance of the film interface. The latter arises from the implantation of nitrogen-cointaining species in the plasma onto the surface of the cation exchange film. 26 refs., 10 figs., 2 tabs.

  19. Plasma Processes and Polymers: 16th International Symposium on Plasma Chemistry Taormina, Italy June 22-27, 2003

    Science.gov (United States)

    D'Agostino, Riccardo; Favia, Pietro; Oehr, Christian; Wertheimer, Michael R.

    2005-04-01

    This volume compiles essential contributions to the most innovative fields of Plasma Processes and Polymers. High-quality contributions cover the fields of plasma deposition, plasma treatment of polymers and other organic compounds, plasma processes under partial vacuum and at atmospheric pressure, biomedical, textile, automotive, and optical applications as well as surface treatment of bulk materials, clusters, particles and powders. This unique collection of refereed papers is based on the best contributions presented at the 16th International Symposium on Plasma Chemistry in Taormina, Italy (ISPC-16, June 2003). A high class reference of relevance to a large audience in plasma community as well as in the area of its industrial applications.

  20. Optimization of Process Parameters of Tool Wear in Turning Operation

    Directory of Open Access Journals (Sweden)

    Manik Barman

    2015-04-01

    Full Text Available Tool Wear is of great apprehension in machining industries since itaffects the surface quality, dimensional accuracy and production cost of the materials / components. In the present study twenty seven experiments were conducted as per 3 parameter 3 level full factorial design for turning operation of a mild steel specimen with high speed steel (HSS cutting tool. An experimental investigation on cutting tool wear and a mathematical model for tool wear estimation is reported in this paper where the model was simulated by computer programming and it has been found that this model is capable of estimating the wear rate of cutting tool and it provides an optimum set of process parameters for minimum tool wear.

  1. Improving gravitational-wave parameter estimation using Gaussian process regression

    CERN Document Server

    Moore, Christopher J; Chua, Alvin J K; Gair, Jonathan R

    2015-01-01

    Folding uncertainty in theoretical models into Bayesian parameter estimation is necessary in order to make reliable inferences. A general means of achieving this is by marginalising over model uncertainty using a prior distribution constructed using Gaussian process regression (GPR). Here, we apply this technique to (simulated) gravitational-wave signals from binary black holes that could be observed using advanced-era gravitational-wave detectors. Unless properly accounted for, uncertainty in the gravitational-wave templates could be the dominant source of error in studies of these systems. We explain our approach in detail and provide proofs of various features of the method, including the limiting behaviour for high signal-to-noise, where systematic model uncertainties dominate over noise errors. We find that the marginalised likelihood constructed via GPR offers a significant improvement in parameter estimation over the standard, uncorrected likelihood. We also examine the dependence of the method on the ...

  2. Raw material changes and their processing parameters in an extrusion cooking process

    DEFF Research Database (Denmark)

    Cheng, Hongyuan; Friis, Alan

    In this work, the effects of raw material and process parameters on product expansion in a fish feed extrusion process were investigated. Four different recipes were studied with a pilot-scale twin-screw co-rotating extruder according to a set of pre-defined processing conditions. In the four...

  3. Intrahippocampal Infusion of Crotamine Isolated from Crotalus durissus terrificus Alters Plasma and Brain Biochemical Parameters

    Directory of Open Access Journals (Sweden)

    Rithiele Gonçalves

    2014-11-01

    Full Text Available Crotamine is one of the main constituents of the venom of the South American rattlesnake Crotalus durissus terrificus. Here we sought to investigate the inflammatory and toxicological effects induced by the intrahippocampal administration of crotamine isolated from Crotalus whole venom. Adult rats received an intrahippocampal infusion of crotamine or vehicle and were euthanized 24 h or 21 days after infusion. Plasma and brain tissue were collected for biochemical analysis. Complete blood count, creatinine, urea, glutamic oxaloacetic transaminase (GOT, glutamic pyruvic transaminase (GPT, creatine-kinase (CK, creatine kinase-muscle B (CK-MB and oxidative parameters (assessed by DNA damage and micronucleus frequency in leukocytes, lipid peroxidation and protein carbonyls in plasma and brain were quantified. Unpaired and paired t-tests were used for comparisons between saline and crotamine groups, and within groups (24 h vs. 21 days, respectively. After 24 h crotamine infusion promoted an increase of urea, GOT, GPT, CK, and platelets values (p ≤ 0.01, while red blood cells, hematocrit and leukocytes values decreased (p ≤ 0.01. Additionally, 21 days after infusion crotamine group showed increased creatinine, leukocytes, TBARS (plasma and brain, carbonyl (plasma and brain and micronucleus compared to the saline-group (p ≤ 0.01. Our findings show that crotamine infusion alter hematological parameters and cardiac markers, as well as oxidative parameters, not only in the brain, but also in the blood, indicating a systemic pro-inflammatory and toxicological activity. A further scientific attempt in terms of preserving the beneficial activity over toxicity is required.

  4. Ignitor Plasma Physics Performance in the H-Regime at Various Parameters

    Science.gov (United States)

    Detragiache, P.; Coppi, B.

    2010-11-01

    The plasma physics performance of Ignitor at full (BT = 13 T, Ip = 10 MA) as well as at reduced parameters (BT = 8 T, Ip = 5 MA) in the high confinement mode (H-regime) is assessed using global 0-D modelling. At full parameters, high-Q operation is possible if the heating power (a combination of Ohmic, α and limited ICRF power) is above the threshold value Pthr for H-regime confinement. Different scaling expressions for Pthr yield significantly different results when used with Ignitor parameters. Even with the most pessimistic among the proposed scalingsootnotetextY. R. Martin et al., Journal of Physics: Conference Series, 123, 012033 (2008). the access to H-regime confinement is possible for Ignitor at full field when the ICRH system is operated at the highest frequency and the generated power is less than at lower frequencies. At reduced parameters, the lower Pthr and the augmented ICRF power available (about 10 MW) facilitate access to H-regime confinement, while the plasma performance remains respectable.

  5. Reconstruction of the ion plasma parameters from the current measurements: mathematical tool

    Directory of Open Access Journals (Sweden)

    E. Séran

    Full Text Available Instrument d’Analyse du Plasma (IAP is one of the instruments of the newly prepared ionospheric mission Demeter. This analyser was developed to measure flows of thermal ions at the altitude of ~ 750 km and consists of two parts: (i retarding potential analyser (APR, which is utilised to measure the energy distribution of the ion plasma along the sensor look direction, and (ii velocity direction analyser (ADV, which is used to measure the arrival angle of the ion flow with respect to the analyser axis. The necessity to obtain quick and precise estimates of the ion plasma parameters has prompted us to revise the existing mathematical tool and to investigate different instrumental limitations, such as (i finite angular aperture, (ii grid transparency, (iii potential depression in the space between the grid wires, (iv losses of ions during their passage between the entrance diaphragm and the collector. Simple analytical expressions are found to fit the currents, which are measured by the APR and ADV collectors, and show a very good agreement with the numerical solutions. It was proven that the fitting of the current with the model functions gives a possibility to properly resolve even minor ion concentrations and to find the arrival angles of the ion flow in the multi-species plasma. The discussion is illustrated by an analysis of the instrument response in the ionospheric conditions which are predicted by the International Reference Ionosphere (IRI model.

    Key words. Ionosphere (plasma convection; instruments and techniques – Space plasma physics (experimental and mathematical techniques

  6. Influence of plasma parameters on the growth and properties of magnetron sputtered CNx thin films

    Science.gov (United States)

    Hellgren, Niklas; Macák, Karol; Broitman, Esteban; Johansson, Mats P.; Hultman, Lars; Sundgren, Jan-Eric

    2000-07-01

    Carbon nitride CNx thin films were grown by unbalanced dc magnetron sputtering from a graphite target in a pure N2 discharge, and with the substrate temperature Ts kept between 100 and 550 °C. A solenoid coil positioned in the vicinity of the substrate was used to support the magnetic field of the magnetron, so that the plasma could be increased near the substrate. By varying the coil current and gas pressure, the energy distribution and fluxes of N2+ ions and C neutrals could be varied independently of each other over a wide range. An array of Langmuir probes in the substrate position was used to monitor the radial ion flux distribution over the 75-mm-diam substrate, while the flux and energy distribution of neutrals was estimated through Monte Carlo simulations. The structure, surface roughness, and mechanical response of the films are found to be strongly dependent on the substrate temperature, and the fluxes and energies of the deposited particles. By controlling the process parameters, the film structure can thus be selected to be amorphous, graphite-like or fullerene-like. When depositing at 3 mTorr N2 pressure, with Ts>200 °C, a transition from a disordered graphite-like to a hard and elastic fullerene-like structure occurred when the ion flux was increased above ˜0.5-1.0 mA/cm2. The nitrogen-to-carbon concentration ratio in the films ranged from ˜0.1 to 0.65, depending on substrate temperature and gas pressure. The nitrogen film concentration did, however, not change when varying the nitrogen ion-to-carbon atom flux ratios from ˜1 to 20.

  7. Unraveling the Processing Parameters in Friction Stir Welding

    Science.gov (United States)

    Schneider, Judy; Nunes, Arthur C., Jr.

    2005-01-01

    In friction stir welding (FSW), a rotating threaded pin tool is translated along a weld seam, literally stirring the edges of the seam together. To determine optimal processing parameters for producing a defect free weld, a better understanding of the resulting metal deformation flow path or paths is required. In this study, various markers are used to trace the flow paths of the metal. X-ray radiographs record the segmentation and position of the wire. Several variations in the trajectories can be differentiated within the weld zone.

  8. Intelligent Industrial Transmitters of Pressure and Other Process Parameters

    Directory of Open Access Journals (Sweden)

    B. L. Miljković

    2009-11-01

    Full Text Available An overview is given of industrial measurement instruments (transmitters of pressure and other process parameters. It is followed by a description of the technology used in the current generation of intelligent transmitters featuring two-way digital communication. A recently developed product of IHTM–CMTM, the intelligent pressure transmitter is presented, including a description of the software temperature compensation method for the used pressure sensor. Features and application possibilities of the developed hardware and software platform are discussed, as well as its suitability for the realization of wireless sensors.

  9. Nonlinear processes in the strong wave-plasma interaction

    Science.gov (United States)

    Pegoraro, Francesco; Califano, Francesco; Attico, Nicola; Bulanov, Sergei

    2000-10-01

    Nonlinear interactions in hot laboratory and/or astrophysical plasmas are a very efficient mechanism able to transfer the energy from the large to the small spatial scales of the system. As a result, kinetic processes are excited and play a key role in the plasma dynamics since the typical fluid dissipative length scales (where the nonlinear cascade is stopped) are (much) smaller then the kinetic length scales. Then, the key point is the role of the kinetic effects in the global plasma dynamics, i.e. whether the kinetic effects remains confined to the small scales of the system or whether there is a significant feedback on the large scales. Here we will address this problem by discussing the nonlinear kinetic evolution of the electromagnetic beam plasma instability where phase space vortices, as well as large scale vortex like magnetic structures in the physical space, are generated by wave - particle interactions. The role and influence of kinetic effects on the large scale plasma dynamics will be also discussed by addressing the problem of collisionless magnetic reconection.

  10. Process characteristics of fibre-laser-assisted plasma arc welding

    Energy Technology Data Exchange (ETDEWEB)

    Mahrle, A; Schnick, M; Rose, S; Demuth, C; Beyer, E; Fuessel, U, E-mail: achim.mahrle@iws.fraunhofer.de [Dresden University of Technology, Institute of Surface and Manufacturing Technology, PO Box, D-01062 Dresden (Germany)

    2011-08-31

    Experimental and theoretical investigations on fibre-laser-assisted plasma arc welding (LAPW) were performed. Welding experiments were carried out on aluminium and steel sheets. In the case of a highly focused laser beam and a separate arrangement of plasma torch and laser beam, high-speed video recordings of the plasma arc and corresponding measurements of the time-dependent arc voltage revealed differences in the process behaviour for both materials. In the case of aluminium welding, a sharp decline in arc voltage and stabilization and guiding of the anodic arc root was observed whereas in steel welding the arc voltage was slightly increased after the laser beam was switched on. However, significant improvement of the melting efficiency with the combined action of plasma arc and laser beam was achieved for both types of material. Theoretical results of additional numerical simulations of the arc behaviour suggest that the properties of the arc plasma are mainly influenced not by a direct interaction with the laser radiation but by the laser-induced evaporation of metal. Arc stabilization with increased current densities is predicted for moderate rates of evaporated metal only whereas metal vapour rates above a certain threshold causes a destabilization of the arc and reduced current densities along the arc axis.

  11. Plasma process optimization for N-type doping applications

    Energy Technology Data Exchange (ETDEWEB)

    Raj, Deven; Persing, Harold; Salimian, Siamak; Lacey, Kerry; Qin Shu; Hu, Jeff Y.; McTeer, Allen [Applied Materials, Inc., Varian Semiconductor Business Unit, 35 Dory Road, Gloucester, MA 01930 (United States); Micron Technology, Inc., 8000 S. Federal Way, Boise, ID 83707 (United States)

    2012-11-06

    Plasma doping (PLAD) has been adopted across the implant technology space and into high volume production for both conventional DRAM and NAND doping applications. PLAD has established itself as an alternative to traditional ion implantation by beamline implantation. The push for high doping concentration, shallow doping depth, and conformal doping capability expand the need for a PLAD solution to meet such requirements. The unique doping profile and doping characteristics at high dose rates allow for PLAD to deliver a high throughput, differentiated solution to meet the demand of evolving transistor technology. In the PLAD process, ions are accelerated to the wafer as with a negative wafer bias applied to the wafer. Competing mechanisms, such as deposition, sputtering, and etching inherent in plasma doping require unique control and process optimization. In this work, we look at the distinctive process tool control and characterization features which enable an optimized doping process using n-type (PH{sub 3} or AsH{sub 3}) chemistries. The data in this paper will draw the relationship between process optimization through plasma chemistry study to the wafer level result.

  12. Characteristic Features of the Formation of a Combined Magnetron-Laser Plasma in the Processes of Deposition of Film Coatings

    Science.gov (United States)

    Burmakov, A. P.; Kuleshov, V. N.; Prokopchik, K. Yu.

    2016-09-01

    A block diagram of a facility for combined magnetron-laser deposition of coatings and of the systems of controlling and managing this process is considered. The results of analysis of the influence of the gas medium and of laser radiation parameters on the emission-optical properties of laser plasma are considered. The influence of the laser plasma on the electric characteristics of a magnetron discharge is analyzed. The formation of the laser plasma-initiated pulse arc discharge has been established and the influence of the laser radiation parameters on the electric characteristics of this discharge has been determined. The emission optical spectra of the magnetron discharge plasma and of erosion laser plasma are compared separately and in combination.

  13. On-line estimation of concentration parameters in fermentation processes

    Institute of Scientific and Technical Information of China (English)

    XIONG Zhi-hua; HUANG Guo-hong; SHAO Hui-he

    2005-01-01

    It has long been thought that bioprocess, with their inherent measurement difficulties and complex dynamics, posed almost insurmountable problems to engineers. A novel software sensor is proposed to make more effective use of those measurements that are already available, which enable improvement in fermentation process control. The proposed method is based on mixtures of Gaussian processes (GP) with expectation maximization (EM) algorithm employed for parameter estimation of mixture of models. The mixture model can alleviate computational complexity of GP and also accord with changes of operating condition in fermentation processes, i.e., it would certainly be able to examine what types of process-knowledge would be most relevant for local models' specific operating points of the process and then combine them into a global one. Demonstrated by on-line estimate of yeast concentration in fermentation industry as an example, it is shown that soft sensor based state estimation is a powerful technique for both enhancing automatic control performance of biological systems and implementing on-line monitoring and optimization.

  14. DYNAMIC OF CHANGES OF BLOOD PLASMA ENERGY METABOLISM PARAMETERS IN SUCKLING COWS DURING CALVING INTERVAL

    Directory of Open Access Journals (Sweden)

    Ales Pavlik

    2015-02-01

    Full Text Available In this study, effect of environmental condition changes during gazing period on energy metabolism parameters was investigated. Totally 40 Aberdeen Angus cows were selected for observation. Calving all of cows was situated into March. The feeding ration for the animals was comprised by pasture during the grazing period and corn silage, hay and granulated distiller’s grains during the winter period. At average age 9 days before calving, and subsequently 10, 81, 151, 189 and 273 days after calving, blood was sampled and analysed for glucose and NEFA (non-esterified fatty acid concentrations on KONELAB T20xt automatic analyser (Thermo Fisher Scientific, Finland and currently available commercial kits (Biovendor-Laboratorni medicina, Czech Republic. A rapid increase (p < 0.05 of glucose concentration was detected in blood plasma of cows in period before calving to 81 days post partum. Average value of glucose concentration at 273 days postpartum was significant (p < 0.05 lower comparing to day 189. The highest concentrations of NEFA in blood plasma of cows were found at 10 day postpartum. After that, during the persisted higher temperature period the NEFA concentration decreased significantly (p < 0.01 till 189 days postpartum. At the end of monitored period concentration of NEFA in blood plasma significantly decreased (p < 0.05. Changes of hot and cold season during the grazing period probably according to forage quality and had significant effects on blood plasma NEFA and glucose concentrations.

  15. Educational software for the visualization of space plasma processes

    Science.gov (United States)

    Russell, C. T.; Le, G.; Luhmann, J. G.; Littlefield, B.

    1995-01-01

    The UCLA Space Physics Group has developed educational software composed of a series of modules to assist students with understanding basic concepts of space plasmas and charged particle motion. Present modules cover planetary magnetospheres, charged particle motion, cold plasma waves, collisionless shock waves, and solar wind. The software is designed around the principle that students can learn more by doing rather than by reading or listening. The programs provide a laboratory-like environment in which the student can control, observe, and measure complex behavior. The interactive graphics environment allows the student to visualize the results of his or her experimentation and to try different parameters as desired. The current version of the software runs on UNIX-based operating systems in an X-Windows environment. It has been used in a classroom setting at both UCLA and the University of California at San Diego.

  16. Double Glow Plasma Surface Alloying Process Modeling Using Artificial Neural Networks

    Institute of Scientific and Technical Information of China (English)

    Jiang XU; Xishan XIE; Zhong XU

    2003-01-01

    A model is developed for predicting the correlation between processing parameters and the technical target of double glowby applying artificial neural network (ANN). The input parameters of the neural network (NN) are source voltage, workpiecevoltage, working pressure and distance between source electrode and workpiece. The output of the NN model is three importanttechnical targets, namely the gross element content, the thickness of surface alloying layer and the absorption rate (the ratioof the mass loss of source materials to the increasing mass of workpiece) in the processing of double glow plasma surfacealloying. The processing parameters and technical target are then used as a training set for an artificial neural network. Themodel is based on multiplayer feedforward neural network. A very good performance of the neural network is achieved and thecalculated results are in good agreement with the experimental ones.

  17. Parameters for viable process combinations; Randbedingungen fuer sinnvolle Verfahrenskombinationen

    Energy Technology Data Exchange (ETDEWEB)

    Lahl, U.; Zeschmar-Lahl, B. [BZL Kommunikation und Projektsteuerung GmbH, Oyten (Germany)

    1998-09-01

    The following parameters merit examination in determining the viability of process combinations: conceptual and technical soundness, environmental acceptability, energy balance, flexibility, costs, economic risk potential. The present contribution on this subject is not intended to take the place of or cover the scope of single-case studies. In practice, viability studies on process combinations have to deal with concrete plans involving precisely defined material flow balances, emissions, costs etc. The present paper therefore only presents the basic principles of this type of study. [Deutsch] Folgende Randbedingungen fuer sinnvolle Verfahrenskombinationen sind zu untersuchen: - konzeptionelle und technische Stimmigkeit, - Umweltvertraeglichkeit, - energetische Bilanz, - Flexibilitaet, - Kosten, - oekonomisches Risikopotential. Nun kann dieser Beitrag zum Thema keine Einzelfallbetrachtung ersetzen bzw. abdecken. Im Rahmen einer echten Pruefung auf `Sinnhaftigkeit` einer Kombinationsloesung stehen sich ganz konkrete Planungen gegenueber, die wiederum mit definierten Stoffflussbilanzen, Emissionen, Kosten usw. verbunden sind. Im Rahmen dieser Betrachtung koennen nur die Grundzuege einer derartigen Pruefung dargestellt werden. (orig.)

  18. Characteristics, Process Parameters, and Inner Components of Anaerobic Bioreactors

    Science.gov (United States)

    Abdelgadir, Awad; Chen, Xiaoguang; Liu, Jianshe; Xie, Xuehui; Zhang, Jian; Zhang, Kai; Wang, Heng; Liu, Na

    2014-01-01

    The anaerobic bioreactor applies the principles of biotechnology and microbiology, and nowadays it has been used widely in the wastewater treatment plants due to their high efficiency, low energy use, and green energy generation. Advantages and disadvantages of anaerobic process were shown, and three main characteristics of anaerobic bioreactor (AB), namely, inhomogeneous system, time instability, and space instability were also discussed in this work. For high efficiency of wastewater treatment, the process parameters of anaerobic digestion, such as temperature, pH, Hydraulic retention time (HRT), Organic Loading Rate (OLR), and sludge retention time (SRT) were introduced to take into account the optimum conditions for living, growth, and multiplication of bacteria. The inner components, which can improve SRT, and even enhance mass transfer, were also explained and have been divided into transverse inner components, longitudinal inner components, and biofilm-packing material. At last, the newly developed special inner components were discussed and found more efficient and productive. PMID:24672798

  19. 工艺参数对激光重熔等离子喷涂Ni基WC复合涂层影响%Effect of Process Parameters on Plasma-Sprayed Ni-Based and WC Composited Coatings by Laser Remelting

    Institute of Scientific and Technical Information of China (English)

    王东生; 田宗军; 屈光; 杨斌; 沈理达; 黄因慧

    2012-01-01

    The effects of laser remelting parameters on microstructure and properties of nickel (Ni) -based and tungsten carbide (WC) composited coatings prepared by plasma spraying were studied. The microstructural characteristics, microhardness, fiction and wear behaviour of the coatings were investigated using scanning electron microscopy (SEM), microhardness measurement and a ball—on-disk tribometer. The results show that the defects of as -sprayed coating like lamellar stacking microstructure and pores were eliminated by laser remelting, and the remelted coating possessed a denser microstructure. With the increase of the laser power, the burning loss and dissolve of the WC particles is increased, while the dilution of the coating becomes large. The laser-remelted samples had higher hardness, better wear resistance than the as-sprayed coating. Laser power has a great impact on the coating and an optimized process parameter is help to achieve appropriate melting of WC particles, which lead to retain a high proportion of hard phase in the coating, good combination between the WC particles and the Ni-base matrix alloy, so that the coating owns high microhardness and wear resistance.%采用激光重熔工艺对等离子喷涂预置Ni基WC复合涂层进行处理,研究了激光工艺参数对涂层微观组织和性能的影响.用扫描电镜(SEM)、显微硬度计和球-盘式摩擦磨损机分析了涂层微观结构、显微硬度和高温摩擦磨损特性.结果表明,激光重熔消除了等离子喷涂层的片层状结构、孔隙等缺陷,涂层致密性提高;随着激光功率的增加,WC颗粒烧损和溶解增多,同时涂层稀释率变大;激光重熔处理后涂层的显微硬度和磨损性能显著高于原等离子喷涂层,但激光功率对其有较大的影响,工艺参数的合理选择有利于WC颗粒适当熔化,从而在涂层中保留较高比例的硬质相,同时使WC颗粒与Ni基体的结合较强,达到较高的显微硬度和耐磨性能.

  20. Laser plasma simulations of the generation processes of Alfven and collisionless shock waves in space plasma

    Science.gov (United States)

    Prokopov, P. A.; Zakharov, Yu P.; Tishchenko, V. N.; Shaikhislamov, I. F.; Boyarintsev, E. L.; Melekhov, A. V.; Ponomarenko, A. G.; Posukh, V. G.; Terekhin, V. A.

    2016-11-01

    Generation of Alfven waves propagating along external magnetic field B0 and Collisionless Shock Waves propagating across B0 are studied in experiments with laser- produced plasma and magnetized background plasma. The collisionless interaction of interpenetrating plasma flows takes place through a so-called Magnetic Laminar Mechanism (MLM) or Larmor Coupling. At the edge of diamagnetic cavity LP-ions produce induction electric field Eφ which accelerates BP-ions while LP-ions rotate in opposite direction. The ions movement generates sheared azimuthal magnetic field Bφ which could launches torsional Alfven wave. In previous experiments at KI-1 large scale facility a generation of strong perturbations propagating across B0 with magnetosonic speed has been studied at a moderate value of interaction parameter δ∼0.3. In the present work we report on experiments at conditions of 5∼R2 and large Alfven-Mach number MA∼10 in which strong transverse perturbations traveling at a scale of ∼1 m in background plasma at a density of ∼3*1013 cm-3 is observed. At the same conditions but smaller MA ∼ 2 a generation, the structure and dynamic of Alfven wave with wavelength ∼0.5 m propagating along fields B0∼100÷500 G for a distance of ∼2.5 m is studied.

  1. Parameter and Process Significance in Mechanistic Modeling of Cellulose Hydrolysis

    Science.gov (United States)

    Rotter, B.; Barry, A.; Gerhard, J.; Small, J.; Tahar, B.

    2005-12-01

    The rate of cellulose hydrolysis, and of associated microbial processes, is important in determining the stability of landfills and their potential impact on the environment, as well as associated time scales. To permit further exploration in this field, a process-based model of cellulose hydrolysis was developed. The model, which is relevant to both landfill and anaerobic digesters, includes a novel approach to biomass transfer between a cellulose-bound biofilm and biomass in the surrounding liquid. Model results highlight the significance of the bacterial colonization of cellulose particles by attachment through contact in solution. Simulations revealed that enhanced colonization, and therefore cellulose degradation, was associated with reduced cellulose particle size, higher biomass populations in solution, and increased cellulose-binding ability of the biomass. A sensitivity analysis of the system parameters revealed different sensitivities to model parameters for a typical landfill scenario versus that for an anaerobic digester. The results indicate that relative surface area of cellulose and proximity of hydrolyzing bacteria are key factors determining the cellulose degradation rate.

  2. Sensitivity analysis on parameters and processes affecting vapor intrusion risk.

    Science.gov (United States)

    Picone, Sara; Valstar, Johan; van Gaans, Pauline; Grotenhuis, Tim; Rijnaarts, Huub

    2012-05-01

    A one-dimensional numerical model was developed and used to identify the key processes controlling vapor intrusion risks by means of a sensitivity analysis. The model simulates the fate of a dissolved volatile organic compound present below the ventilated crawl space of a house. In contrast to the vast majority of previous studies, this model accounts for vertical variation of soil water saturation and includes aerobic biodegradation. The attenuation factor (ratio between concentration in the crawl space and source concentration) and the characteristic time to approach maximum concentrations were calculated and compared for a variety of scenarios. These concepts allow an understanding of controlling mechanisms and aid in the identification of critical parameters to be collected for field situations. The relative distance of the source to the nearest gas-filled pores of the unsaturated zone is the most critical parameter because diffusive contaminant transport is significantly slower in water-filled pores than in gas-filled pores. Therefore, attenuation factors decrease and characteristic times increase with increasing relative distance of the contaminant dissolved source to the nearest gas diffusion front. Aerobic biodegradation may decrease the attenuation factor by up to three orders of magnitude. Moreover, the occurrence of water table oscillations is of importance. Dynamic processes leading to a retreating water table increase the attenuation factor by two orders of magnitude because of the enhanced gas phase diffusion.

  3. Optimization of polyetherimide processing parameters for optical interconnect applications

    Science.gov (United States)

    Zhao, Wei; Johnson, Peter; Wall, Christopher

    2015-10-01

    ULTEM® polyetherimide (PEI) resins have been used in opto-electronic markets since the optical properties of these materials enable the design of critical components under tight tolerances. PEI resins are the material of choice for injection molded integrated lens applications due to good dimensional stability, near infrared (IR) optical transparency, low moisture uptake and high heat performance. In most applications, parts must be produced consistently with minimal deviations to insure compatibility throughout the lifetime of the part. With the large number of lenses needed for this market, injection molding has been optimized to maximize the production rate. These optimized parameters for high throughput may or may not translate to an optimized optical performance. In this paper, we evaluate and optimize PEI injection molding processes with a focus on optical property performance. A commonly used commercial grade was studied to determine factors and conditions which contribute to optical transparency, color, and birefringence. Melt temperature, mold temperature, injection speed and cycle time were varied to develop optimization trials and evaluate optical properties. These parameters could be optimized to reduce in-plane birefringence from 0.0148 to 0.0006 in this study. In addition, we have studied an optically smooth, sub-10nm roughness mold to re-evaluate material properties with minimal influence from mold quality and further refine resin and process effects for the best optical performance.

  4. Sensitivity analysis on parameters and processes affecting vapor intrusion risk

    KAUST Repository

    Picone, Sara

    2012-03-30

    A one-dimensional numerical model was developed and used to identify the key processes controlling vapor intrusion risks by means of a sensitivity analysis. The model simulates the fate of a dissolved volatile organic compound present below the ventilated crawl space of a house. In contrast to the vast majority of previous studies, this model accounts for vertical variation of soil water saturation and includes aerobic biodegradation. The attenuation factor (ratio between concentration in the crawl space and source concentration) and the characteristic time to approach maximum concentrations were calculated and compared for a variety of scenarios. These concepts allow an understanding of controlling mechanisms and aid in the identification of critical parameters to be collected for field situations. The relative distance of the source to the nearest gas-filled pores of the unsaturated zone is the most critical parameter because diffusive contaminant transport is significantly slower in water-filled pores than in gas-filled pores. Therefore, attenuation factors decrease and characteristic times increase with increasing relative distance of the contaminant dissolved source to the nearest gas diffusion front. Aerobic biodegradation may decrease the attenuation factor by up to three orders of magnitude. Moreover, the occurrence of water table oscillations is of importance. Dynamic processes leading to a retreating water table increase the attenuation factor by two orders of magnitude because of the enhanced gas phase diffusion. © 2012 SETAC.

  5. Highly Segmented Thermal Barrier Coatings Deposited by Suspension Plasma Spray: Effects of Spray Process on Microstructure

    Science.gov (United States)

    Chen, Xiaolong; Honda, Hiroshi; Kuroda, Seiji; Araki, Hiroshi; Murakami, Hideyuki; Watanabe, Makoto; Sakka, Yoshio

    2016-12-01

    Effects of the ceramic powder size used for suspension as well as several processing parameters in suspension plasma spraying of YSZ were investigated experimentally, aiming to fabricate highly segmented microstructures for thermal barrier coating (TBC) applications. Particle image velocimetry (PIV) was used to observe the atomization process and the velocity distribution of atomized droplets and ceramic particles travelling toward the substrates. The tested parameters included the secondary plasma gas (He versus H2), suspension injection flow rate, and substrate surface roughness. Results indicated that a plasma jet with a relatively higher content of He or H2 as the secondary plasma gas was critical to produce highly segmented YSZ TBCs with a crack density up to 12 cracks/mm. The optimized suspension flow rate played an important role to realize coatings with a reduced porosity level and improved adhesion. An increased powder size and higher operation power level were beneficial for the formation of highly segmented coatings onto substrates with a wider range of surface roughness.

  6. Temporal evolution of the spectral lines emission and temperatures in laser induced plasmas through characteristic parameters

    Energy Technology Data Exchange (ETDEWEB)

    Bredice, F., E-mail: faustob@ciop.unlp.edu.ar [Centro de Investigaciones Ópticas, P.O. Box 3 C. P.1897 Gonnet, La Plata (Argentina); Pacheco Martinez, P. [Grupo de Espectroscopía Óptica de Emisión y Láser, Universidad del Atlántico, Barranquilla (Colombia); Sánchez-Aké, C.; Villagrán-Muniz, M. [Laboratorio de Fotofísica, Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, Apartado Postal 70-186, México D.F. 04510 (Mexico)

    2015-05-01

    In this work, we propose an extended Boltzmann plot method to determine the usefulness of spectral lines for plasma parameter calculations. Based on the assumption that transient plasmas are under ideal conditions during an specific interval of time Δt, (i.e. thin, homogeneous and in local thermodynamic equilibrium (LTE)), the associated Boltzmann plots describe a surface in the space defined by the coordinates X = Energy, Y = Time and Z = ln (λ{sub jl}I{sub j}/g{sub j}A{sub jl}), where I{sub j} is the integrated intensity of the spectral line, g{sub j} is the statistical weight of the level j, λ{sub jl} is the wavelength of the considered line and A{sub jl} is its transition rate. In order to express the Boltzmann plot surface in terms of a reduced set of constants B{sub i}, and δ{sub i}, we developed as a power series of time, the logarithm of I{sub n}(t)/I{sub n}(t{sub 0}), where I{sub n}(t) is the integrated intensity of any spectral line at time t, and I{sub n}(t{sub 0}) at initial time. Moreover, the temporal evolution of the intensity of any spectral line and consequently the temperature of the plasma can be also expressed with these constants. The comparison of the temporal evolution of the line intensity calculated using these constants with their experimental values, can be used as a criterion for selecting useful lines in plasma analysis. Furthermore, this method can also be applied to determine self-absorption or enhancement of the spectral lines, to evaluate a possible departure of LTE, and to check or estimate the upper level energy value of any spectral line. An advantage of this method is that the value of these constants does not depend on the spectral response of the detection system, the uncertainty of the transition rates belonging to the analyzed spectral lines or any other time-independent parameters. In order to prove our method, we determined the constants B{sub i} and δ{sub i} and therefore the Boltzmann plot surface from the temporal

  7. Thermal plasma processed ferro-magnetically ordered face-centered cubic iron at room temperature

    Science.gov (United States)

    Raut, Suyog A.; Kanhe, Nilesh S.; Bhoraskar, S. V.; Das, A. K.; Mathe, V. L.

    2014-10-01

    Here, we report tailor made phase of iron nanoparticles using homogeneous gas phase condensation process via thermal plasma route. It was observed that crystal lattice of nano-crystalline iron changes as a function of operating parameters of the plasma reactor. In the present investigation iron nanoparticles have been synthesized in presence of argon at operating pressures of 125-1000 Torr and fixed plasma input DC power of 6 kW. It was possible to obtain pure fcc, pure bcc as well as the mixed phases for iron nanoparticles in powder form as a function of operating pressure. The as synthesized product was characterized for understanding the structural and magnetic properties by using X-ray diffraction, vibrating sample magnetometer, and Mössbauer spectroscopy. The data reveal that fcc phase is ferromagnetically ordered with high spin state, which is unusual whereas bcc phase is found to be ferromagnetic as usual. Finally, the structural and magnetic properties are co-related.

  8. Predicting parameters of degradation succession processes of Tibetan Kobresia grasslands

    Science.gov (United States)

    Lin, L.; Li, Y. K.; Xu, X. L.; Zhang, F. W.; Du, Y. G.; Liu, S. L.; Guo, X. W.; Cao, G. M.

    2015-11-01

    In the past two decades, increasing human activity (i.e., overgrazing) in the Tibetan Plateau has strongly influenced plant succession processes, resulting in the degradation of alpine grasslands. Therefore, it is necessary to diagnose the degree of degradation to enable implementation of appropriate management for sustainable exploitation and protection of alpine grasslands. Here, we investigated environmental factors and plant functional group (PFG) quantity factors during the alpine grassland succession processes. Principal component analysis (PCA) was used to identify the parameters indicative of degradation. We divided the entire degradation process into six stages. PFG types shifted from rhizome bunchgrasses to rhizome plexus and dense-plexus grasses during the degradation process. Leguminosae and Gramineae plants were replaced by sedges during the advanced stages of degradation. The PFGs were classified into two reaction groups: the grazing-sensitive group, containing Kobresia humilis Mey, and Gramineae and Leguminosae plants, and the grazing-insensitive group, containing Kobresia pygmaea Clarke. The first group was correlated with live root biomass in the surface soil (0-10 cm), whereas the second group was strongly correlated with mattic epipedon thickness and K. pygmaea characteristics. The degree of degradation of alpine meadows may be delineated by development of mattic epipedon and PFG composition. Thus, meadows could be easily graded and their use adjusted based on our scaling system, which would help prevent irreversible degradation of important grasslands. Because relatively few environmental factors are investigated, this approach can save time and labor to formulate a conservation management plan for degraded alpine meadows.

  9. Dynamics of electronegative plasmas for materials processing. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Lichtenberg, A.J.; Lieberman, M.A.

    1996-12-31

    The purpose of this project is to study the equilibrium particle and energy balance and the heating mechanisms in electronegative r.f. discharges. Particular attention is given to the formation of non-Maxwellian electron distributions and their effect on the macroscopic parameters. The research includes theory, particle-in-cell simulation, and experimental investigations. The sheath heating theory and the simulation results developed for electropositive plasmas are used to guide the investigations. The investigation was centered on, but is not limited to, the study of oxygen feedstock gas in capacitively and inductively coupled r.f. discharges. 15 refs.

  10. The Influence of Parameters Affecting Boron Removal by Electrocoagulation Process

    KAUST Repository

    Zeboudji, B.

    2013-04-01

    Boron removal in seawater desalination presents a particular challenge. In seawater reverse osmosis (SWRO) systems boron removal at low concentration (<0.5 mg/L) is usually achieved by a second pass using brackish water RO membranes. However, this process requires chemical addition and important additional investment, operation and maintenance, and energy costs. Electrocoagulation (EC) process can be used to achieve such low boron concentration. In this work, the removal of boron from aqueous solution was carried out by EC process using aluminum and iron electrodes. Several operating parameters on the removal efficiency such as initial pH, current density, initial boron ion concentration, feed concentration, gap between electrodes, and electrode material, were investigated. In the case of bipolar electrocoagulation (BEC), an optimum removal efficiency of 96% corresponding to a final boron concentration of 0.4 mg/L was achieved at a current density of 6 mA/cm2 and pH = 8 using aluminum electrodes. The concentration of NaCl was 2,500 mg/L and the gap between the electrodes of 0.5 cm. Furthermore, a comparison between monopolar electrocoagulation (MEC) and BEC using both aluminum and iron electrodes was carried out. Results showed that the BEC process has reduced the current density applied to obtain high level of boron removal in a short reaction time compared to MEC process. The high performance of the EC showed that the process could be used to reduce boron concentration to acceptable levels at low-cost and more environmentally friendly. © 2013 Copyright Taylor and Francis Group, LLC.

  11. Plasma nitriding monitoring reactor: A model reactor for studying plasma nitriding processes using an active screen

    Energy Technology Data Exchange (ETDEWEB)

    Hamann, S., E-mail: hamann@inp-greifswald.de; Röpcke, J. [INP-Greifswald, Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany); Börner, K.; Burlacov, I.; Spies, H.-J. [TU Bergakademie Freiberg, Institute of Materials Engineering, Gustav-Zeuner-Str. 5, 09599 Freiberg (Germany); Strämke, M.; Strämke, S. [ELTRO GmbH, Arnold-Sommerfeld-Ring 3, 52499 Baesweiler (Germany)

    2015-12-15

    A laboratory scale plasma nitriding monitoring reactor (PLANIMOR) has been designed to study the basics of active screen plasma nitriding (ASPN) processes. PLANIMOR consists of a tube reactor vessel, made of borosilicate glass, enabling optical emission spectroscopy (OES) and infrared absorption spectroscopy. The linear setup of the electrode system of the reactor has the advantages to apply the diagnostic approaches on each part of the plasma process, separately. Furthermore, possible changes of the electrical field and of the heat generation, as they could appear in down-scaled cylindrical ASPN reactors, are avoided. PLANIMOR has been used for the nitriding of steel samples, achieving similar results as in an industrial scale ASPN reactor. A compact spectrometer using an external cavity quantum cascade laser combined with an optical multi-pass cell has been applied for the detection of molecular reaction products. This allowed the determination of the concentrations of four stable molecular species (CH{sub 4}, C{sub 2}H{sub 2}, HCN, and NH{sub 3}). With the help of OES, the rotational temperature of the screen plasma could be determined.

  12. Plasma nitriding monitoring reactor: A model reactor for studying plasma nitriding processes using an active screen

    Science.gov (United States)

    Hamann, S.; Börner, K.; Burlacov, I.; Spies, H.-J.; Strämke, M.; Strämke, S.; Röpcke, J.

    2015-12-01

    A laboratory scale plasma nitriding monitoring reactor (PLANIMOR) has been designed to study the basics of active screen plasma nitriding (ASPN) processes. PLANIMOR consists of a tube reactor vessel, made of borosilicate glass, enabling optical emission spectroscopy (OES) and infrared absorption spectroscopy. The linear setup of the electrode system of the reactor has the advantages to apply the diagnostic approaches on each part of the plasma process, separately. Furthermore, possible changes of the electrical field and of the heat generation, as they could appear in down-scaled cylindrical ASPN reactors, are avoided. PLANIMOR has been used for the nitriding of steel samples, achieving similar results as in an industrial scale ASPN reactor. A compact spectrometer using an external cavity quantum cascade laser combined with an optical multi-pass cell has been applied for the detection of molecular reaction products. This allowed the determination of the concentrations of four stable molecular species (CH4, C2H2, HCN, and NH3). With the help of OES, the rotational temperature of the screen plasma could be determined.

  13. Plasma nitriding monitoring reactor: A model reactor for studying plasma nitriding processes using an active screen.

    Science.gov (United States)

    Hamann, S; Börner, K; Burlacov, I; Spies, H-J; Strämke, M; Strämke, S; Röpcke, J

    2015-12-01

    A laboratory scale plasma nitriding monitoring reactor (PLANIMOR) has been designed to study the basics of active screen plasma nitriding (ASPN) processes. PLANIMOR consists of a tube reactor vessel, made of borosilicate glass, enabling optical emission spectroscopy (OES) and infrared absorption spectroscopy. The linear setup of the electrode system of the reactor has the advantages to apply the diagnostic approaches on each part of the plasma process, separately. Furthermore, possible changes of the electrical field and of the heat generation, as they could appear in down-scaled cylindrical ASPN reactors, are avoided. PLANIMOR has been used for the nitriding of steel samples, achieving similar results as in an industrial scale ASPN reactor. A compact spectrometer using an external cavity quantum cascade laser combined with an optical multi-pass cell has been applied for the detection of molecular reaction products. This allowed the determination of the concentrations of four stable molecular species (CH4, C2H2, HCN, and NH3). With the help of OES, the rotational temperature of the screen plasma could be determined.

  14. Typical Profiles and Distributions of Plasma and Magnetic Field Parameters in Magnetic Clouds at 1 AU

    Science.gov (United States)

    Rodriguez, L.; Masías-Meza, J. J.; Dasso, S.; Démoulin, P.; Zhukov, A. N.; Gulisano, A. M.; Mierla, M.; Kilpua, E.; West, M.; Lacatus, D.; Paraschiv, A.; Janvier, M.

    2016-08-01

    Magnetic clouds (MCs) are a subset of interplanetary coronal mass ejections (ICMEs). They are important because of their simple internal magnetic field configuration, which resembles a magnetic flux rope, and because they represent one of the most geoeffective types of solar transients. In this study, we analyze their internal structure using a superposed epoch method on 63 events observed at L1 by the Advance Composition Explorer (ACE), between 1998 and 2006. In this way, we obtain an average profile for each plasma and magnetic field parameter at each point of the cloud. Furthermore, we take a fixed time-window upstream and downstream from the MC to also sample the regions preceding the cloud and the wake trailing it. We then perform a detailed analysis of the internal characteristics of the clouds and their surrounding solar wind environments. We find that the parameters studied are compatible with log-normal distribution functions. The plasma β and the level of fluctuations in the magnetic field vector are the best parameters to define the boundaries of MCs. We find that one third of the events shows a peak in plasma density close to the trailing edge of the flux ropes. We provide several possible explanations for this result and investigate if the density peak is of a solar origin ( e.g. erupting prominence material) or formed during the magnetic cloud travel from the Sun to 1 AU. The most plausible explanation is the compression due to a fast overtaking flow, coming from a coronal hole located to the east of the solar source region of the magnetic cloud.

  15. Penentuan Efektifitas Oksitetrasiklin Melalui Parameter Farmakokinetik/farmakodinamik pada Plasma dan Jaringan Ayam Broiler

    Directory of Open Access Journals (Sweden)

    Agustina Dwi Wijayanti

    2010-06-01

    Full Text Available A study was conducted to determine the effectiveness of oxytetracycline on the basis of itspharmacokinetic/pharmacodynamic (PK/PD parameters in the plasma and tissues of broiler following a50 mg/kg single dose of intravenous administration. The male broiler were injected with oxytetracycline attarsal medial venous. The blood, liver, kidney and abdominal muscle were collected at 14 points of timesamplings. Blood was centrifuged to obtain plasma and all tissues were extracted with Mc Ilvine buffer.Drug concentration in samples was determined by High Performance Liquid Chromatography (HPLCusing AOAC standard reference for tetracycline. The pharmacokinetic parameters of oxytetracycline werecalculated using non compartment method. The results were as follows. For plasma: the AUC was 790,615,5 ?g/mL minute , Clearance was 63,242 mL/min/kg bb, Tmax/Cmax was 1 minute/0,7 ?g/mL, T1/2elimination was 6,4, hours, Vd was 37 L/kg. For liver ; AUC was 36418,89, minute , Tmax/Cmax was 16hours/17,15 ?g/g, and T1/2 elimination was 24,5, hours. For kidney; AUC6808,41 ?g/g minute , Tmax/Cmax 1 minute/16,73 ?g/g, , T1/2 elimination was 11,55 hours. For muscle; AUC was 3502 ?g/g minute,Tmax/Cmax was 1 minute/2,58 ?g/g, T1/2 elimination was 167,39 hours. The ratio of AUC/MIC inplasma and tissues appeared to a good pharmacokinetic/pharmacodynamic parameter to determine theeffectiveness of oxytetracycline.

  16. A Taguchi approach on optimal process control parameters for HDPE pipe extrusion process

    Science.gov (United States)

    Sharma, G. V. S. S.; Rao, R. Umamaheswara; Rao, P. Srinivasa

    2016-12-01

    High-density polyethylene (HDPE) pipes find versatile applicability for transportation of water, sewage and slurry from one place to another. Hence, these pipes undergo tremendous pressure by the fluid carried. The present work entails the optimization of the withstanding pressure of the HDPE pipes using Taguchi technique. The traditional heuristic methodology stresses on a trial and error approach and relies heavily upon the accumulated experience of the process engineers for determining the optimal process control parameters. This results in setting up of less-than-optimal values. Hence, there arouse a necessity to determine optimal process control parameters for the pipe extrusion process, which can ensure robust pipe quality and process reliability. In the proposed optimization strategy, the design of experiments (DoE) are conducted wherein different control parameter combinations are analyzed by considering multiple setting levels of each control parameter. The concept of signal-to-noise ratio (S/N ratio) is applied and ultimately optimum values of process control parameters are obtained as: pushing zone temperature of 166 °C, Dimmer speed at 08 rpm, and Die head temperature to be 192 °C. Confirmation experimental run is also conducted to verify the analysis and research result and values proved to be in synchronization with the main experimental findings and the withstanding pressure showed a significant improvement from 0.60 to 1.004 Mpa.

  17. EXAFS investigation of nanoparticles produced in a thermal plasma process

    Energy Technology Data Exchange (ETDEWEB)

    Luetzenkirchen-Hecht, D.; Frahm, R. [Heinrich-Heine-Univ. Duesseldorf, Inst. fuer Angewandte Physik (Germany); Buchner, P. [Heinrich-Heine-Univ. Duesseldorf, Inst. fuer Laser- und Plasmaphysik (Germany); Strehblow, H.H. [Heinrich-Heine-Univ., Inst. fuer Physikalische Chemie (Germany)

    1999-11-01

    Nanosized ceramic powders (Cu/SiC, Y{sub 2}O{sub 3}-stabilized cubic ZrO{sub 2}) were produced by evaporation of coarsely grained powders of the respective materials in an inductively coupled thermal plasma process and rapid quenching of the vapor. The atomic short range order of these nanoparticles with an average diameter of about 10 nm was investigated ex situ with EXAFS. The results are compared to crystalline reference materials. (au) 10 refs.

  18. Selenium, copper and zinc in seminal plasma of men with varicocele, relationship with seminal parameters.

    Science.gov (United States)

    Camejo, María Isabel; Abdala, Lyzeth; Vivas-Acevedo, Giovanny; Lozano-Hernández, Ricardo; Angeli-Greaves, Miriam; Greaves, Eduardo D

    2011-12-01

    Varicocele has been associated with decrease in seminal parameters. Selenium (Se), copper (Cu), and zinc (Zn) are trace elements essential for normal spermatogenesis of mammals and play a critical role as antioxidant defense system enzymes. Se, Cu, and Zn are associated with sperm quality in fertile and infertile men. However, there is little information about Se, Cu, and Zn concentrations in semen in patients with varicocele and its association with seminal parameters. The purpose of this study was to determine the concentrations of Se, Cu, and Zn in semen of patients with varicocele and the relationship with seminal parameters. Total Reflection X-Ray Fluorescence was used for the fist time in the seminal fluid analysis. The concentration of selenium in men with varicocele was smaller than the normozoospermic group, while no differences were observed for both concentrations of zinc and copper. A significant positive correlation between zinc and selenium concentration was observed. Selenium in seminal plasma correlates with a good spermatozoa concentrations, motility, and morphology. Additionally, a significant positive correlation was observed between zinc levels and sperm count. In conclusion, a decrease in selenium concentration was associated with detriment of seminal parameters. A study should be conducted to evaluate the benefits of both zinc and selenium supplementation to improve seminal parameters in patients with varicocele.

  19. Deposição por plasma com arco transferido Hardfacing by plasma transfer arc process

    Directory of Open Access Journals (Sweden)

    Víctor Vergara Díaz

    2010-03-01

    Full Text Available Em virtude do Processo de Soldagem Plasma com Alimentação de Pó ter similaridades com o Processo de Soldagem Plasma com Alimentação de Arame, foi realizado um estudo comparativo entre ambos os processos utilizando-se a liga a base de cobalto comercialmente conhecida como Stellite 6, como material de adição na forma de pó e arame. A pesquisa foi realizada com a expectativa de ser aplicada nas operações de revestimentos de superfícies, em especial em pás de turbinas hidráulicas desgastadas por cavitação. A seleção do material de adição a ser empregado depende da natureza do mecanismo de desgaste encontrado. No Labsolda, a liga Stellite 6 vem sendo uma das mais utilizadas, por apresentar uma excelente resistência ao desgaste erosivo por cavitação. Foi avaliada a influência da vazão de gás de plasma a partir dos valores de diluição, dimensões do cordão, dureza e microestrutura. O Processo de Soldagem Plasma com Alimentação de Pó foi o que produziu o melhor acabamento superficial, menor diluição, melhor molhamento e maior largura. Com isto abre-se uma nova perspectiva para revestimentos metálicos e neste contexto se insere a recuperação por soldagem de partes erodidas de turbinas hidráulicas.The Plasma powder transferred arc welding process, which uses feed stock in the powder form, has similarities with Plasma wire transferred arc welding. This work describes a comparative study of the two processes using a Cobalt-based alloy commercially known as Stellite 6. This Co-based alloy is recognized for its superior cavitation erosion resistance. The aim of this work is to investigate the potential of PTA coatings for the protection and refurbishiment hydraulic turbine blades. Coatings were evaluated for the influence of Plasma gas flow rate on coating dilution, geometry, hardness and microstructure. Coatings processed with the atomized Stellite 6 powder feestock showed a superior surface quality, lower dilution

  20. Exploring control parameters of two photon processes in solutions

    Indian Academy of Sciences (India)

    Debabrata Goswami; Amit Nag

    2012-01-01

    Two-photon microscopy depends extensively on the two-photon absorption cross-sections of biologically relevant chromophores. High repetition rate (HRR) lasers are essential in multiphoton microscopy for generating satisfactory signal to noise at low average powers. However, HRR lasers generate thermal distortions in samples even with the slightest single photon absorption. We use an optical chopper with HRR lasers to intermittently `blank’ irradiation and effectively minimize thermal effects to result in a femtosecond z-scan setup that precisely measures the two-photon absorption (TPA) cross-sections of chromophores. Though several experimental factors impact such TPA measurements, a systematic effort to modulate and influence TPA characteristics is yet to evolve. Here, we present the effect of several control parameters on the TPA process that are independent of chromophore characteristics for femtosecond laser pulse based measurements; and demonstrate how the femtosecond laser pulse repetition rate, chromophore environment and incident laser polarization can become effective control parameters for such nonlinear optical properties.

  1. Process parameter optimization for fly ash brick by Taguchi method

    Energy Technology Data Exchange (ETDEWEB)

    Prabir Kumar Chaulia; Reeta Das [Central Mechanical Engineering Research Institute, Durgapur (India)

    2008-04-15

    This paper presents the results of an experimental investigation carried out to optimize the mix proportions of the fly ash brick by Taguchi method of parameter design. The experiments have been designed using an L9 orthogonal array with four factors and three levels each. Small quantity of cement has been mixed as binding materials. Both cement and the fly ash used are indicated as binding material and water binder ratio has been considered as one of the control factors. So the effects of water/binder ratio, fly ash, coarse sand, and stone dust on the performance characteristic are analyzed using signal-to-noise ratios and mean response data. According to the results, water/binder ratio and stone dust play the significant role on the compressive strength of the brick. Furthermore, the estimated optimum values of the process parameters are corresponding to water/binder ratio of 0.4, fly ash of 39%, coarse sand of 24% and stone dust of 30%. The mean value of optimal strength is predicted as 166.22 kg.cm{sup -2} with a tolerance of 10.97 kg.cm{sup -2}. The confirmatory experimental result obtained for the optimum conditions is 160.17 kg.cm{sup -2}. 13 refs., 3 figs., 7 tabs.

  2. Effect of processing parameters on coconut oil expression efficiencies.

    Science.gov (United States)

    Mpagalile, Joseph Jeremiah; Clarke, Brian

    2005-03-01

    The effect of process parameters on oil expression efficiency from freshly dried coconut gratings was investigated. The range of parameters investigated were: pressing time, 4 and 8 min; particle size, fine (0.6 - 1.18 mm) and coarse (1.18 - 2.36 mm); pressure, 3-33 MPa; moisture content, 3%, 7%, 11% and 15%; and temperature, 30 degrees C, 60 degrees C and 90 degrees C. Results showed that 8 min of pressing and finer particles both led to significantly (P oil expression efficiency. The pressure increase within the range 3-13 MPa led to significantly higher oil yields, with yields leveling off thereafter. The effect of pressure increase was highly associated with the moisture content of the gratings, and the optimum moisture content under low-pressure pressing was found to be 11%. A pressing temperature of 60 degrees C led to higher oil expression efficiency, whereas a further increase of temperature to 90 degrees C did not lead to a significant increase in oil yield.

  3. BACTERIAL LEACHING OF ELECTRONIC SCRAP: INFLUENCE OF PROCESS PARAMETERS

    Directory of Open Access Journals (Sweden)

    Luciana Harue Yamane

    2013-03-01

    Full Text Available The application of bacterial leaching in the ore treatment is already known and also can be applied such as treatment of electronic waste to copper recovery. This paper investigates the influence of process parameters (pulp density, inoculums volume, rotation speed and initial concentration of ferrous iron on bacterial leaching of copper from printed circuit board of computers using the bacterium Acidithiobacillus ferrooxidans–LR. Printed circuit boards from computers were comminuted using a hammer mill. The powder obtained was magnetically separated and the non-magnetic material used in this study. A shake flask study was carried out on the non-magnetic material using a shaker. The results show that Acidithiobacillus ferrooxidans–LR can leach 99% of copper from printed circuit boards (non–magnetic material under the determined conditions through of the studies.

  4. Surface temperature: A key parameter to control the propanethiol plasma polymer chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Thiry, Damien, E-mail: damien.thiry@umons.ac.be; Aparicio, Francisco J. [Chimie des Interactions Plasma Surface (ChIPS), CIRMAP, Université de Mons, 23 Place du Parc, B-7000 Mons (Belgium); Laha, Priya; Terryn, Herman [Research Group Electrochemical and Surface Engineering (SURF), Department of Materials and Chemistry (MACH), Pleinlaan 2, 1050 Brussel (Belgium); Snyders, Rony [Chimie des Interactions Plasma Surface (ChIPS), CIRMAP, Université de Mons, 23 Place du Parc, B-7000 Mons, Belgium and Materia Nova Research Center, Parc Initialis, B-7000 Mons (Belgium)

    2014-09-01

    In this work, the influence of the substrate temperature (T{sub s}) on the chemical composition of propanethiol plasma polymers was investigated for a given set of plasma conditions. In a first study, a decrease in the atomic sulfur content (at. %S) with the deposition time (t{sub d}) was observed. This behavior is explained by the heating of the growing film during deposition process, limiting the incorporation of stable sulfur-based molecules produced in the plasma. Experiments carried out by controlling the substrate temperature support this hypothesis. On the other hand, an empirical law relating the T{sub s} and the at. %S was established. This allows for the formation of gradient layer presenting a heterogeneous chemical composition along the thickness, as determined by depth profile analysis combining X-ray photoelectron spectroscopy and C{sub 60} ion gun sputtering. The experimental data fit with the one predicted from our empiric description. The whole set of our results provide new insights in the relationship between the substrate temperature and the sulfur content in sulfur-based plasma polymers, essential for future developments.

  5. Design of a uranium-dioxide powder spheroidization system by plasma processing

    Science.gov (United States)

    Cavender, Daniel

    The plasma spheroidization system (PSS) is the first process in the development of a tungsten-uranium dioxide (W-UO2) ceramic-metallic (cermet) fuel for nuclear thermal rocket (NTR) propulsion. For the purposes of fissile fuel retention, UO2 spheroids ranging in size from 50 - 100 micrometers (μm) in diameter will be encapsulated in a tungsten shell. The PSS produces spherical particles by melting angular stock particles in an argon-hydrogen plasma jet where they become spherical due to surface tension. Surrogate CeO 2 powder was used in place of UO2 for system and process parameter development. Stock and spheroidized powders were micrographed using optical and scanning electron microscopy and evaluated by statistical methods to characterize and compare the spherocity of pre and post process powders. Particle spherocity was determined by irregularity parameter. Processed powders showed a statistically significant improvement in spherocity, with greater that 60% of the examined particles having an irregularity parameter of equal to or lower than 1.2, compared to stock powder.

  6. Grey fuzzy logic approach for the optimization of DLC thin film coating process parameters using PACVD technique

    Science.gov (United States)

    Ghadai, R. K.; Das, P. P.; Shivakoti, I.; Mondal, S. C.; Swain, B. P.

    2017-07-01

    Diamond-like carbon (DLC) coatings are widely used in medical, manufacturing and aerospace industries due to their excellent mechanical, biological, optical and tribological properties. The selection of optimal process parameters for efficient characteristics of DLC film is always a challenging issue for the materials science researchers. The optimal combination of the process parameters involved in the deposition of DLC films provide a better result, which subsequently help other researchers to choose the process parameters. In the present work Grey Relation Analysis (GRA) and Fuzzy-logic are being used for the optimization of process parameters in DLC film coating by using plasma assist chemical vapour deposition (PACVD) technique. The bias voltage, bias frequency, deposition pressure, gas composition are considered as input process parameters and hardness (GPa), Young's modulus (GPa), ratio between diamond to graphic fraction, (Id/Ig) ratio are considered as response parameters. The input parameters are optimized by grey fuzzy analysis. The contribution of individual input parameter is done by ANOVA. In this analysis found that bias voltage having the least influence and gas composition has highest influence in the PACVD deposited DLC films. The grey fuzzy analysis results indicated that optimum results for bias voltage, bias frequency, deposition pressure, gas composition for the DLC thin films are -50 V, 6 kHz, 4 μbar and 60:40 % respectively.

  7. Influence of geometrical parameters on performance of plasma synthetic jet actuator

    Science.gov (United States)

    Zong, Hao-hua; Wu, Yun; Jia, Min; Song, Hui-min; Liang, Hua; Li, Ying-hong; Zhang, Zhi-bo

    2016-01-01

    Plasma synthetic jet actuator (PSJA) has shown wide and promising application prospects in a high speed flow control field, due to its rapid response, high exhaust velocity, and non-moving components. In this paper, the total pressure profile of a plasma synthetic jet (PSJ) is measured and a new method is developed to evaluate the pulsed thrust of the PSJA. The influence of geometrical parameters including the electrode distance, the orifice diameter, and the throat length on PSJA performance is analyzed based on the pulsed thrust, the discharge characteristics, and the schlieren images. When varying the electrode distance, the dominant factor determining the jet intensity is the heating volume instead of the discharge energy. For the arc discharge, the electrode distance should be extended to increase both the jet velocity and the jet duration time. The design of the orifice diameter should be based on the controlled flow field. A large orifice diameter produces a strong perturbation with short time duration, while a small orifice diameter induces a lasting jet with low mass flux. In order to obtain better high frequency performance, the throat length should be shortened on the condition that the structural strength of the PSJA is maintained, while there is almost no influence of the throat length on the single cycle performance of the PSJA. Once the discharge energy is fixed, the pulsed thrust remains almost unchanged with different orifice diameters and throat lengths. These three geometrical parameters are independent to some extent and can be optimized separately.

  8. Performance Testing of Suspension Plasma Sprayed Thermal Barrier Coatings Produced with Varied Suspension Parameters

    Directory of Open Access Journals (Sweden)

    Nicholas Curry

    2015-07-01

    Full Text Available Suspension plasma spraying has become an emerging technology for the production of thermal barrier coatings for the gas turbine industry. Presently, though commercial systems for coating production are available, coatings remain in the development stage. Suitable suspension parameters for coating production remain an outstanding question and the influence of suspension properties on the final coatings is not well known. For this study, a number of suspensions were produced with varied solid loadings, powder size distributions and solvents. Suspensions were sprayed onto superalloy substrates coated with high velocity air fuel (HVAF -sprayed bond coats. Plasma spray parameters were selected to generate columnar structures based on previous experiments and were maintained at constant to discover the influence of the suspension behavior on coating microstructures. Testing of the produced thermal barrier coating (TBC systems has included thermal cyclic fatigue testing and thermal conductivity analysis. Pore size distribution has been characterized by mercury infiltration porosimetry. Results show a strong influence of suspension viscosity and surface tension on the microstructure of the produced coatings.

  9. GROWTH PROCESS OF LOW-TEMPERATURE PLASMA-NITRIDING LAYER ON AUSTENITIC STAINLESS STEEL

    Institute of Scientific and Technical Information of China (English)

    Z.W.Yu; L.Wang; X.L.Xu; J.B.Qiang

    2004-01-01

    The growth process of low-temperature plasma-nitriding layer was investigated by scanning electron microscopy(SEM)and X-ray diffraction(XRD).The layer is composed of expanded fcc phase(γN),whose lattice parameter of the layer increases with process time resulting from increasing the nitrogen content.The layer hardness increases gradually with nitrogen content.The high slip band density on the layer surface observed in situ by SEM shows that the surface yield occurs when supersaturated nitrogen content in the layer attains to some value,which is also responsible for the increase in layer hardness.

  10. Relevant parameter space and stability of spherical tokamaks with a plasma center column

    Science.gov (United States)

    Lampugnani, L. G.; Garcia-Martinez, P. L.; Farengo, R.

    2017-02-01

    A spherical tokamak (ST) with a plasma center column (PCC) can be formed inside a simply connected chamber via driven magnetic relaxation. From a practical perspective, the ST-PCC could overcome many difficulties associated with the material center column of the standard ST reactor design. Besides, the ST-PCC concept can be regarded as an advanced helicity injected device that would enable novel experiments on the key physics of magnetic relaxation and reconnection. This is because the concept includes not only a PCC but also a coaxial helicity injector (CHI). This combination implies an improved level of flexibility in the helicity injection scheme required for the formation and sustainment phases. In this work, the parameter space determining the magnetic structure of the ST-PCC equilibria is studied under the assumption of fully relaxed plasmas. In particular, it is shown that the effect of the external bias field of the PCC and the CHI essentially depends on a single parameter that measures the relative amount of flux of these two entities. The effect of plasma elongation on the safety factor profile and the stability to the tilt mode are also analyzed. In the first part of this work, the stability of the system is explained in terms of the minimum energy principle, and relevant stability maps are constructed. While this picture provides an adequate insight into the underlying physics of the instability, it does not include the stabilizing effect of line-tying at the electrodes. In the second part, a dynamical stability analysis of the ST-PCC configurations, including the effect of line-tying, is performed by numerically solving the magnetohydrodynamic equations. A significant stability enhancement is observed when the PCC contains more than the 70% of the total external bias flux, and the elongation is not higher than two.

  11. Effect of transient scrotal hyperthermia on sperm parameters, seminal plasma biochemical markers, and oxidative stress in men

    Directory of Open Access Journals (Sweden)

    Meng Rao

    2015-01-01

    Full Text Available In this experimental prospective study, we aimed to analyze the effect of transient scrotal hyperthermia on the male reproductive organs, from the perspective of sperm parameters, semen plasma biochemical markers, and oxidative stress, to evaluate whether different frequencies of heat exposure cause different degrees of damage to spermatogenesis. Two groups of volunteers (10 per group received testicular warming in a 43°C water bath 10 times, for 30 min each time: group 1: 10 consecutive days; group 2: once every 3 days. Sperm parameters, epididymis and accessory sex gland function, semen plasma oxidative stress and serum sex hormones were tested before treatment and in the 16-week recovery period after treatment. At last, we found an obvious reversible decrease in sperm concentration (P = 0.005 for Group 1 and P= 0.008 for Group 2 when the minimums were compared with baseline levels, the same below, motility (P = 0.009 and 0.021, respectively, the hypoosmotic swelling test score (P = 0.007 and 0.008, respectively, total acrosin activity (P = 0.018 and 0.009, respectively, and an increase in the seminal plasma malondialdehyde concentration (P = 0.005 and 0.017, respectively. The decrease of sperm concentration was greater for Group 2 than for Group 1 (P = 0.031. We concluded that transient scrotal hyperthermia seriously, but reversibly, negatively affected the spermatogenesis, oxidative stress may be involved in this process. In addition, intermittent heat exposure more seriously suppresses the spermatogenesis compared to consecutive heat exposure. This may be indicative for clinical infertility etiology analysis and the design of contraceptive methods based on heat stress.

  12. Advanced Plasma Pyrolysis Assembly (PPA) Reactor and Process Development

    Science.gov (United States)

    Wheeler, Richard R., Jr.; Hadley, Neal M.; Dahl, Roger W.; Abney, Morgan B.; Greenwood, Zachary; Miller, Lee; Medlen, Amber

    2012-01-01

    Design and development of a second generation Plasma Pyrolysis Assembly (PPA) reactor is currently underway as part of NASA's Atmosphere Revitalization Resource Recovery effort. By recovering up to 75% of the hydrogen currently lost as methane in the Sabatier reactor effluent, the PPA helps to minimize life support resupply costs for extended duration missions. To date, second generation PPA development has demonstrated significant technology advancements over the first generation device by doubling the methane processing rate while, at the same time, more than halving the required power. One development area of particular interest to NASA system engineers is fouling of the PPA reactor with carbonaceous products. As a mitigation plan, NASA MSFC has explored the feasibility of using an oxidative plasma based upon metabolic CO2 to regenerate the reactor window and gas inlet ports. The results and implications of this testing are addressed along with the advanced PPA reactor development.

  13. Process fuel equivalent (PFE)-a new parameter for process and energy audit

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharyyu, S.

    1983-04-01

    Process fuel equivalent (PFE) is an energy audit parameter which takes care of all the factors involved in the manufacturing process. In this parameter, all energy items--direct or indirect including those of purchased reagents, fluxes and other raw materials--are converted into a single variable fuel equivalent, and indicated the same in appropriate energy units. PFE value is an inverse order of efficiency--a low value corresponds to high efficiency. In this article, the PFE method has been used for production of copper from mine to wire bar.

  14. Magnetic Reconnection: A Fundamental Process in Space Plasmas

    Science.gov (United States)

    Hesse, Michael

    2010-01-01

    For many years, collisionless magnetic reconnect ion has been recognized as a fundamental process, which facilitates plasma transport and energy release in systems ranging from the astrophysical plasmas to magnetospheres and even laboratory plasma. Beginning with work addressing solar dynamics, it has been understood that reconnection is essential to explain solar eruptions, the interaction of the solar wind with the magnetosphere, and the dynamics of the magnetosphere. Accordingly, the process of magnetic reconnection has been and remains a prime target for space-based and laboratory studies, as well as for theoretical research. Much progress has been made throughout the years, beginning with indirect verifications by studies of processes enabled by reconnection, such as Coronal Mass Ejections, Flux Transfer Events, and Plasmoids. Theoretical advances have accompanied these observations, moving knowledge beyond the Sweet-Parker theory to the recognition that other, collisionless, effects are available and likely to support much faster reconnect ion rates. At the present time we are therefore near a break-through in our understanding of how collisionless reconnect ion works. Theory and modeling have advanced to the point that two competing theories are considered leading candidates for explaining the microphysics of this process. Both theories predict very small spatial and temporal scales. which are. to date, inaccessible to space-based or laboratory measurements. The need to understand magnetic reconnect ion has led NASA to begin the implementation of a tailored mission, Magnetospheric MultiScale (MMS), a four spacecraft cluster equipped to resolve all relevant spatial and temporal scales. In this presentation, we present an overview of current knowledge as well as an outlook towards measurements provided by MMS.

  15. Enhancement of the neutral-beam stopping cross section in fusion plasmas due to multistep collision processes

    Energy Technology Data Exchange (ETDEWEB)

    Boley, C.D.; Janev, R.K.; Post, D.E.

    1983-10-01

    Multistep processes involving excited atomic states are found to produce a substantial increase in the stopping cross section for a neutral hydrogen beam injected into a plasma, and thus to reduce the beam penetration. For typical plasma and beam parameters of current large tokamak experiments, the stopping cross-sectional enhancement is found to vary from 25% to 50% depending on the beam energy, plasma density, and impurity level. For neutral hydrogen beams with energies greater than or equal to 500 keV, envisioned in tokamak amd mirror reactor designs, the enhancement can be as large as 80 to 90%.

  16. Evaluation of the Effect of Different Plasma-Nitriding Parameters on the Properties of Low-Alloy Steel

    Science.gov (United States)

    Zdravecká, Eva; Slota, Ján; Solfronk, Pavel; Kolnerová, Michaela

    2017-07-01

    This work is concerned with the surface treatment (ion nitriding) of different plasma-nitriding parameters on the characteristics of DIN 1.8519 low-alloy steel. The samples were nitrided from 500 to 570 °C for 5-40 h using a constant 25% N2-75% H2 gaseous mixture. Lower temperature (500-520 °C) favors the formation of compound layers of γ' and ɛ iron nitrides in the surface layers, whereas a monophase γ'-Fe4 N layer can be obtained at a higher temperature. The hardness of this layer can be obtained when nitriding is performed at a higher temperature, and the hardness decreases when the temperature increases to 570 °C. These results indicate that pulsed plasma nitriding is highly efficient at 550 °C and can form thick and hard nitrided layers with satisfactory mechanical properties. The results show the optimized nitriding process at 540 °C for 20 h. This process can be an interesting means of enhancing the surface hardness of tool steels to forge dies compared to stamped steels with zinc coating with a reduced coefficient of friction and improving the anti-sticking properties of the tool surface.

  17. The influence of active screen plasma nitriding parameters on corrosion behavior of a low-alloy steel

    Energy Technology Data Exchange (ETDEWEB)

    Ahangarani, Sh., E-mail: ahangarani@irost.i [Department of Advanced Materials and Renewable Energies, Iranian Research Organization for Science and Technology (IROST), P.O. Box 15815-3538, Tehran (Iran, Islamic Republic of); Sabour, A.R. [Department of Materials Engineering, Tarbiat Modarres University, Tehran (Iran, Islamic Republic of); Mahboubi, F. [Department of Mining and Metallurgical Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Shahrabi, T. [Department of Materials Engineering, Tarbiat Modarres University, Tehran (Iran, Islamic Republic of)

    2009-09-18

    This work presents a comparative study of low-alloy steel nitriding for different possible techniques. Active screen plasma nitriding (ASPN) is a successful surface modification method that has many advantages over the conventional DC plasma nitriding (CPN). The corrosion behavior of 30CrNiMo8 low-alloy steel has been examined using anodic polarization tests in 3.5% NaCl solution under varying conditions of ASPN and CPN processes. The process variables included active screen setup parameters, treatment temperature (550 and 580 deg. C), gas mixture (25/75 and 75/25 of N{sub 2}/H{sub 2}) and treatment time (5 and 10 h) in 500 Pa pressure. The structure and phases composition of the compound layer was studied by X-ray diffraction (XRD), microhardness tests, optical microscopy and scanning electron microscopy (SEM). It was observed that ASPN treated samples surface enhanced corrosion resistance while the temperature and/or hole size of screen setup increased.

  18. Mechanism and operation parameters of a plasma-driven micro-particle accelerator

    Institute of Scientific and Technical Information of China (English)

    HUANG JianGuo; FENG ChunHua; HAN dianWei; LI HongWei; CAI MingHui; LI XiaoYin; ZHANG ZhenLong; CHEN ZhaoFeng; WANG Long; YANG XuanZong

    2009-01-01

    There is a large amount of micro debris ranging between millimeters and micrometers in space, which has significant influence on the reliability and life of spacecrafts through long-duration integrated im-pacts and has to be considered in designing a vehicle's suitability to the space environment. In order to simulate the micro-impacts on exposed materials, a plasma-driven micro-particle accelerator was de-veloped. The major processes, including the acceleration, compression and ejection of plasmas, were modeled. By comparing the theoretical simulations with the experimental results, the acceleration mechanism was clarified. Moreover, through a series of experiments, the optimum operation range was investigated, and the acceleration ability was primarily determined.

  19. GeV electron acceleration by a Gaussian field laser with effect of beam width parameter in magnetized plasma

    Science.gov (United States)

    Ghotra, Harjit Singh; Kant, Niti

    2017-01-01

    Electron acceleration due to a circularly polarized (CP) Gaussian laser field has been investigated theoretically in magnetized plasma. A Gaussian laser beam possesses trapping forces on electrons during its propagation through plasma. A single particle simulation indicates a resonant enhancement of electron acceleration with a Gaussian laser beam. The plasma is magnetized with an axial magnetic field in same direction as that of laser beam propagation. The dependence of laser beam width parameter on electron energy gain with propagation distance has been presented graphically for different values of laser intensity. Electron energy gain is relatively high where the laser beam parameter is at its minimum value. Enhanced energy gain of the order of GeV is reported with magnetic field under 20 MG in plasma. It is also seen that the axial magnetic field maintains the electron acceleration for large propagation distance even with an increasing beam width parameter.

  20. Relationship between Lipids Levels of Serum and Seminal Plasma and Semen Parameters in 631 Chinese Subfertile Men.

    Directory of Open Access Journals (Sweden)

    Jin-Chun Lu

    Full Text Available This prospective study was designed to investigate the relationship between lipids levels in both serum and seminal plasma and semen parameters.631 subfertile men were enrolled. Their obesity-associated markers were measured, and semen parameters were analyzed. Also, seminal plasma and serum TC, TG, HDL and LDL and serum FFA, FSH, LH, total testosterone (TT, estradiol (E2 and SHBG levels were detected.Seminal plasma and serum TG, TC and LDL levels were positively related to age. Serum TC, TG and LDL were positively related to obesity-associated markers (P < 0.001, while only seminal plasma TG was positively related to them (P < 0.05. For lipids levels in serum and seminal plasma, only TG level had slightly positive correlation between them (r = 0.081, P = 0.042. There was no significant correlation between serum lipids levels and semen parameters. However, seminal plasma TG, TC, LDL and HDL levels were negatively related to one or several semen parameters, including semen volume (SV, sperm concentration (SC, total sperm count (TSC, sperm motility, progressive motility (PR and total normal-progressively motile sperm counts (TNPMS. Moreover, seminal plasma TG, TC, LDL and HDL levels in patients with oligospermatism, asthenospermia and teratozoospermia were higher than those with normal sperm concentration, motility or morphology. After adjusting age and serum LH, FSH, TT, E2 and SHBG levels, linear regression analysis showed that SV was still significantly correlated with seminal plasma LDL (P = 0.012, both of SC and TSC with seminal plasma HDL (P = 0.028 and 0.002, and both of PR and sperm motility with seminal plasma TC (P = 0.012 and 0.051.The abnormal metabolism of lipids in male reproductive system may contribute to male factor infertility.

  1. Optimisation of shock absorber process parameters using failure mode and effect analysis and genetic algorithm

    Science.gov (United States)

    Mariajayaprakash, Arokiasamy; Senthilvelan, Thiyagarajan; Vivekananthan, Krishnapillai Ponnambal

    2013-07-01

    The various process parameters affecting the quality characteristics of the shock absorber during the process were identified using the Ishikawa diagram and by failure mode and effect analysis. The identified process parameters are welding process parameters (squeeze, heat control, wheel speed, and air pressure), damper sealing process parameters (load, hydraulic pressure, air pressure, and fixture height), washing process parameters (total alkalinity, temperature, pH value of rinsing water, and timing), and painting process parameters (flowability, coating thickness, pointage, and temperature). In this paper, the process parameters, namely, painting and washing process parameters, are optimized by Taguchi method. Though the defects are reasonably minimized by Taguchi method, in order to achieve zero defects during the processes, genetic algorithm technique is applied on the optimized parameters obtained by Taguchi method.

  2. Review of relaxation oscillations in plasma processing discharges

    Institute of Scientific and Technical Information of China (English)

    Zhou Zhu-Wen; M.A.Lieberman; Sungjin Kim

    2007-01-01

    Relaxation oscillations due to plasma instabilities at frequencies ranging from a few Hz to tens of kHz have been observed in various types of plasma processing discharges.Relaxation oscillations have been observed in electropositive capacitive discharges between a powered anode and a metallic chamber whose periphery iS grounded through a slot with dielectric spacers.The oscillations of time-varying optical emission from the main discharge chamber show,for example,a high-frequency (~40 kHz) relaxation oscillation at 13.33Pa,with an absorbed power being nearly the peripheral breakdown power,and a low-frequency (~3 Hz) oscillation,with an even higher absorbed power.The high-frequency oscillation is found to ignite plasma in the slot,but usually not in the peripheral chamber.The kilohertz oscillations are modelled using an electromagnetic model of the slot impedance,coupled to a circuit analysis of the system including the matching network.The model results are in general agreement with the experimental observations,and indicate a variety of behaviours dependent on the matching conditions.In low-pressure inductive discharges,oscillations appear in the transition between low-density capacitively driven and high-density inductively driven discharges when attaching gases such as SF6 and Ar/SF6 mixtures are used.Oscillations of charged particles,plasma potential,and light,at frequencies ranging from a few Hz to tens of kHz,are seen for gas pressures between 0.133 Pa and 13.33 Pa and discharge powers in a range of 75-1200 W.The region of instability increases as the plasma becomes more electronegative,and the frequency of plasma oscillation increases as the power,pressure,and gas flow rate increase.A volume-averaged (global) model of the kilohertz instability has been developed;the results obtained from the model agree well with the experimental observations.

  3. Plasma aided coal gasification and the variables in this process

    Energy Technology Data Exchange (ETDEWEB)

    Pang, X.; Lu, Y.; Zhu, S. [Taiyuan University of Technology, Taiyuan (China)

    2005-12-15

    In order to investigate the characters of plasma aided coal gasification in the industry-scale equipment, the tests with changing feeding rate, steam output pressure, feeding gas flux, input power of plasma generator and the additives were carried out with Datong coal. The produced gas components were analyzed by gas chromatography. And the optimal process conditions, such as, the feeding rate of 150 g/min, the feeding gas flow of 18 m{sup 3}/h, the output power of plasma generator of 100 kW, the steam output pressure of 0.3 MPa are obtained. When the contents of CaO and CaCO{sub 3} in the whole feed are 10 and 5% respectively, the experimental data show their catalytic effect is the best. Considering the molar mass of CaO and CaCO{sub 3}, it is concluded that the catalytic effect of CaO is more important than the reduction of CO{sub 2} in the gasification. 12 refs., 2 figs., 3 tabs.

  4. Electron-silane scattering cross section for plasma assisted processes

    Science.gov (United States)

    Verma, Pankaj; Kaur, Jaspreet; Antony, Bobby

    2017-03-01

    Silane is an important molecule with numerous applications to natural and technological plasmas. In such environments, where plasma assisted processes are vital, electron induced reactions play a major role in its chemistry. In view of this, electron induced scattering of molecules such as silane finds significance. This article reports a comprehensive study of electron impact cross sections for silane over a wide energy range. In particular, the emphasis is given in providing a complete dataset for various electron scattering events possible with silane. Such dataset is the need for the plasma modeling community. Moreover, literature survey shows that the cross section database for silane is fragmentary. To fill this void, we have computed the differential elastic, total, rotational excitation, and momentum transfer cross sections. Two formalisms that are reliable in their energy domain are employed to accomplish the task: the R-matrix method through QUANTEMOL-N at low incident energies and the spherical complex optical potential formalism at intermediate to high energies. Interestingly, the comparison of the present cross section exhibits a good concurrence with the previous data, wherever available.

  5. Nuclear magnetic resonance-based metabonomics reveals strong sex effect on plasma metabolism in 17-year-old Scandinavians and correlation to retrospective infant plasma parameters.

    Science.gov (United States)

    Bertram, Hanne Christine; Duus, Jens Ø; Petersen, Bent O; Hoppe, Camilla; Larnkjaer, Anni; Schack-Nielsen, Lene; Mølgaard, Christian; Michaelsen, Kim F

    2009-07-01

    Nuclear magnetic resonance (NMR)-based metabonomics was carried out on plasma samples from a total of seventy-five 17-year-old Danes to investigate the impact of key parameters such as sex, height, weight, and body mass index on the plasma metabolite profile in a normal, healthy population. Principal component analysis identified sex to have a large impact on the NMR plasma metabolome, whereas no apparent effects of height, weight, and body mass index were found. Partial least square regression discriminant analysis and quantification of relative metabolite concentrations by integration of NMR signals revealed that the sex effect included differences in plasma lipoproteins (mainly high-density lipoprotein), glucose, choline, and amino acid content. Accordingly, the present study suggests a higher lipid synthesis in young women than young men and a higher protein turnover in young men compared with women. Data on plasma content of triglyceride, lipoprotein fractions, and cholesterol at an age of 9 months were available for selected individuals (n = 40); and partial least square regressions revealed correlations between these infant parameters and the NMR plasma metabolome at an age of 17 years. In conclusion, the present study demonstrates the feasibility of NMR-based metabonomics for obtaining a deeper insight into interindividual differences in metabolism and for exploring relationships between parameters measured early in life and metabolic status at a later stage.

  6. Efficiency of the Inertia Friction Welding Process and Its Dependence on Process Parameters

    Science.gov (United States)

    Senkov, O. N.; Mahaffey, D. W.; Tung, D. J.; Zhang, W.; Semiatin, S. L.

    2017-07-01

    It has been widely assumed, but never proven, that the efficiency of the inertia friction welding (IFW) process is independent of process parameters and is relatively high, i.e., 70 to 95 pct. In the present work, the effect of IFW parameters on process efficiency was established. For this purpose, a series of IFW trials was conducted for the solid-state joining of two dissimilar nickel-base superalloys (LSHR and Mar-M247) using various combinations of initial kinetic energy ( i.e., the total weld energy, E o), initial flywheel angular velocity ( ω o), flywheel moment of inertia ( I), and axial compression force ( P). The kinetics of the conversion of the welding energy to heating of the faying sample surfaces ( i.e., the sample energy) vs parasitic losses to the welding machine itself were determined by measuring the friction torque on the sample surfaces ( M S) and in the machine bearings ( M M). It was found that the rotating parts of the welding machine can consume a significant fraction of the total energy. Specifically, the parasitic losses ranged from 28 to 80 pct of the total weld energy. The losses increased (and the corresponding IFW process efficiency decreased) as P increased (at constant I and E o), I decreased (at constant P and E o), and E o (or ω o) increased (at constant P and I). The results of this work thus provide guidelines for selecting process parameters which minimize energy losses and increase process efficiency during IFW.

  7. Relationships between organohalogen contaminants and blood plasma clinical–chemical parameters in chicks of three raptor species from Northern Norway

    DEFF Research Database (Denmark)

    Sonne, Christian; Bustnes, Jan Ove; Herzke, Dorte

    2010-01-01

    Organohalogen contaminants (OHCs) may affect various physiological parameters in birds including blood chemistry. We therefore examined blood plasma clinical-chemical parameters and OHCs in golden eagle, white-tailed eagle and goshawk chicks from Northern Norway. Correlation analyses on pooled da...

  8. High Temperature Epoxy Foam: Optimization of Process Parameters

    Directory of Open Access Journals (Sweden)

    Samira El Gazzani

    2016-06-01

    Full Text Available For many years, reduction of fuel consumption has been a major aim in terms of both costs and environmental concerns. One option is to reduce the weight of fuel consumers. For this purpose, the use of a lightweight material based on rigid foams is a relevant choice. This paper deals with a new high temperature epoxy expanded material as substitution of phenolic resin, classified as potentially mutagenic by European directive Reach. The optimization of thermoset foam depends on two major parameters, the reticulation process and the expansion of the foaming agent. Controlling these two phenomena can lead to a fully expanded and cured material. The rheological behavior of epoxy resin is studied and gel time is determined at various temperatures. The expansion of foaming agent is investigated by thermomechanical analysis. Results are correlated and compared with samples foamed in the same temperature conditions. The ideal foaming/gelation temperature is then determined. The second part of this research concerns the optimization of curing cycle of a high temperature trifunctional epoxy resin. A two-step curing cycle was defined by considering the influence of different curing schedules on the glass transition temperature of the material. The final foamed material has a glass transition temperature of 270 °C.

  9. Relation of Plasma Uric Acid Levels and the Lipid Parameters in Han and Uygur Ethnicity

    Institute of Scientific and Technical Information of China (English)

    Sun Yuping; Yao Hua; Yao Wenhai; Li Qing; You Lan; Wang Qiuyun; Jiang Yan

    2006-01-01

    Objectives Hyperuricemia is a common finding in hypertension and hyperlipidemia,they are all correlated to cardiovascular diseases. The aim of this study was to find the relationship of uric acid and plasma lipid parameters of Han and Uygur ethnicity in Xinjiang. Methods This cross-sectional health examination survey was based on a population random sample from the Urumchi, It included 1166 subjects aged from 20 to 70 years. Serum biochemical testing by Automatic Analyzer (HITACHI 7600-010).Results The uric acid in Han was higher than in Uygur(P< 0.05), men were higher than women in two ethnicities; For lipid parameters men were higher than women, in TG and HDL women were higher than in men in two ethnicity (P < 0.05). Serum uric acid was strongly related to serum triglycerides in Han as well as Uygur ethnicity ( P < 0.001); Compared with the normal group, UA, TG, CHOL, VLDL had ascending trend and HDL had descending trend (P <0.05 ) among groups in Han and Uygur ethnicity,especially Hyperuricemia-hypertriglyceridemia group,uric acid and most some lipid parameters was higher than Hyperuricemia and hypertriglyceridemia group,The prevalence of different groups in Han and Urgur was significantly different (P < 0.05). Conclusions This study shows that the UA and some lipid parameters are different in Han and Uygur ethnicity and show sexual difference; serum uric acid is markedly related to serum triglycerides; Hyperuricemia and hypertriglyceridemia show cooperated effect in uric acid and most lipid parameters. Considering the growing incidence of the potential link between hyperuricemia/hypertriglyceridemia and cardiovascular diseases, more emphasis should be put on the evolving prevalence of hyperuricemia and hypertriglyceridemia in Xinjiang.

  10. Scattering processes and electrical conductivity of partially ionized hydrogen plasma

    Energy Technology Data Exchange (ETDEWEB)

    Ramazanov, T. [Fachbereich Physik, Universitaet Rostock, D-18051 Rostock (Germany); SRIETP, Al Farabi Kazakh National University, Tole bi, 96a, 480012, Almaty (Kazakhstan); Galiyev, K.; Dzhumagulova, K.N. [SRIETP, Al Farabi Kazakh National University, Tole bi, 96a, 480012, Almaty (Kazakhstan); Roepke, G.; Redmer, R. [Fachbereich Physik, Universitaet Rostock, D-18051 Rostock (Germany)

    2003-07-01

    We consider partially ionized hydrogen plasma for the density region n{sub e} = (10{sup 18} / 10{sup 22}) cm{sup -} {sup 3}. The cross sections for scattering processes between the particles are calculated within the partial wave method. Charged particles in the system (electrons, protons) interact via an effective potential that takes into account three-particle correlations. The Buckingham polarization potential is used to describe electron-atom and proton-atom interactions. The electrical conductivity is determined using the Chapman-Enskog method. The results are compared with other available data. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  11. Lupin seeds lower plasma lipid concentrations and normalize antioxidant parameters in rats

    Directory of Open Access Journals (Sweden)

    Osman, M.

    2011-06-01

    Full Text Available This study was designed to test bitter and sweet lupin seeds for lipid-lowering and for their antioxidative activities in hypercholesterolemic rats. The levels of plasma lipid, malondialdehyde (MDA and whole blood reduced glutathione (GSH, as well as the activities of transaminases (ALT and AST, lactate dehydrogenase (LDH in plasma, superoxide dismutase (SOD, glutathione peroxidase (GPx in erythrocytes and plasma glutathione reductase (GR, glutathione-S-transferase (GST and catalase (CAT were examined. A hypercholesterolemia-induced diet manifested in the elevation of total lipids (TL, total cholesterol (TC, triglycerides (TG, LDL-C and MDA levels, ALT, AST, LDH activities and the depletion of GSH and enzymic antioxidants. The supplementation of a hypercholesterolemia-induced diet with bitter and sweet lupin seeds significantly lowered the plasma levels of TL, TC, TG and LDL-C. ALT, AST and LDH activities slightly decreased in treated groups compared with the hypercholesterolemic group (HC. Furthermore, the content of GSH significantly increased while MDA significantly decreased in treated groups compared with the HC group. In addition, the bitter lupin seed group improved enzymic antioxidants compared with the HC group. In general, the results indicated that the bitter lupin seed supplements are better than those containing sweet lupin seeds. These results suggested that the hypocholesterolemic effect of bitter and sweet lupin seed supplements might be due to their abilities to lower the plasma cholesterol level as well as to slow down the lipid peroxidation process and to enhance the antioxidant enzyme activity.

    Este estudio fue diseñado para evaluar semillas de altramuces dulces y amargas como agentes que bajan los lípidos y estudiar su efecto en la actividad antioxidante en ratas hipercolesterolémicas. El nivel de lípidos en plasma, malondialdehido (MDA y glutatión reducido (GSH, así como la actividad transaminasa (ALT y AST

  12. Real-Time Plasma Process Condition Sensing and Abnormal Process Detection

    Directory of Open Access Journals (Sweden)

    Ryan Yang

    2010-06-01

    Full Text Available The plasma process is often used in the fabrication of semiconductor wafers. However, due to the lack of real-time etching control, this may result in some unacceptable process performances and thus leads to significant waste and lower wafer yield. In order to maximize the product wafer yield, a timely and accurately process fault or abnormal detection in a plasma reactor is needed. Optical emission spectroscopy (OES is one of the most frequently used metrologies in in-situ process monitoring. Even though OES has the advantage of non-invasiveness, it is required to provide a huge amount of information. As a result, the data analysis of OES becomes a big challenge. To accomplish real-time detection, this work employed the sigma matching method technique, which is the time series of OES full spectrum intensity. First, the response model of a healthy plasma spectrum was developed. Then, we defined a matching rate as an indictor for comparing the difference between the tested wafers response and the health sigma model. The experimental results showed that this proposal method can detect process faults in real-time, even in plasma etching tools.

  13. Relationship between Lipids Levels of Serum and Seminal Plasma and Semen Parameters in 631 Chinese Subfertile Men

    Science.gov (United States)

    Yao, Qi; Fan, Kai; Wang, Guo-Hong; Feng, Rui-Xiang; Liang, Yuan-Jiao; Chen, Li; Ge, Yi-Feng; Yao, Bing

    2016-01-01

    Objective This prospective study was designed to investigate the relationship between lipids levels in both serum and seminal plasma and semen parameters. Methods 631 subfertile men were enrolled. Their obesity-associated markers were measured, and semen parameters were analyzed. Also, seminal plasma and serum TC, TG, HDL and LDL and serum FFA, FSH, LH, total testosterone (TT), estradiol (E2) and SHBG levels were detected. Results Seminal plasma and serum TG, TC and LDL levels were positively related to age. Serum TC, TG and LDL were positively related to obesity-associated markers (P lipids levels in serum and seminal plasma, only TG level had slightly positive correlation between them (r = 0.081, P = 0.042). There was no significant correlation between serum lipids levels and semen parameters. However, seminal plasma TG, TC, LDL and HDL levels were negatively related to one or several semen parameters, including semen volume (SV), sperm concentration (SC), total sperm count (TSC), sperm motility, progressive motility (PR) and total normal-progressively motile sperm counts (TNPMS). Moreover, seminal plasma TG, TC, LDL and HDL levels in patients with oligospermatism, asthenospermia and teratozoospermia were higher than those with normal sperm concentration, motility or morphology. After adjusting age and serum LH, FSH, TT, E2 and SHBG levels, linear regression analysis showed that SV was still significantly correlated with seminal plasma LDL (P = 0.012), both of SC and TSC with seminal plasma HDL (P = 0.028 and 0.002), and both of PR and sperm motility with seminal plasma TC (P = 0.012 and 0.051). Conclusion The abnormal metabolism of lipids in male reproductive system may contribute to male factor infertility. PMID:26726884

  14. Multi-objective process parameter optimization for energy saving in injection molding process

    Institute of Scientific and Technical Information of China (English)

    Ning-yun LU; Gui-xia GONG; Yi YANG; Jian-hua LU

    2012-01-01

    This paper deals with a multi-objective parameter optimization framework for energy saving in injection molding process.It combines an experimental design by Taguchi's method,a process analysis by analysis of variance (ANOVA),a process modeling algorithm by artificial neural network (ANN),and a multi-objective parameter optimization algorithm by genetic algorithm (GA)-based lexicographic method.Local and global Pareto analyses show the trade-off between product quality and energy consumption.The implementation of the proposed framework can reduce the energy consumption significantly in laboratory scale tests,and at the same time,the product quality can meet the pre-determined requirements.

  15. Feed gas humidity: a vital parameter affecting a cold atmospheric-pressure plasma jet and plasma-treated human skin cells

    Science.gov (United States)

    Winter, J.; Wende, K.; Masur, K.; Iseni, S.; Dünnbier, M.; Hammer, M. U.; Tresp, H.; Weltmann, K.-D.; Reuter, S.

    2013-07-01

    In this study, the effect of feed gas humidity on the reactive component generation of an atmospheric-pressure argon plasma jet and its effect on human skin cells are investigated. Feed gas humidity is identified as one key parameter that strongly influences stability and reproducibility of plasma medical studies. The plasma jet is investigated by absorption spectroscopy in the ultraviolet and infrared spectral region for its ozone production depending on the humidity concentration in the feed gas. By optical emission spectroscopy the dependence of present excited plasma species such as hydroxyl radicals, molecular nitrogen, argon and atomic oxygen on the feed gas humidity is investigated. As an interface layer between the plasma jet effluent and the biological cell, a buffer solution is treated and the hydrogen peroxide (H2O2) production is studied with two independent colorimetric assays as a function of humidity admixture to the feed gas. Ultimately, the effect of varying feed gas humidity on the cell viability of indirect plasma treated adherent HaCAT cells is investigated. The highest viability is found for the driest feed gas condition. Furthermore, this work shows answers for the relevance of unwanted—or intended—feed gas humidity in plasma medical experiments and their comparatively large relevance with respect to ambient humidity. The findings will lead to more reproducible experiments in the field of plasma medicine.

  16. Processing of bulk Al7075 alloy by spark plasma sintering

    Science.gov (United States)

    Málek, P.; Molnárová, O.; Cinert, J.; Lukáč, F.; Chráska, T.

    2017-02-01

    The main advantages of powder metallurgy processing route are the possibility to produce near-net-shape compacts and to minimize the finish machining and material loss. The main problem in particle consolidation process is to suppress porosity, to remove oxide layers, and to retain the microstructure of powder materials. Spark plasma sintering (SPS) combines concurrent uniaxial pressure and direct heating by a pulsed DC current. Sintering occurs at relatively low temperatures for a short time and does not influence significantly the microstructure in the interiors of original powder particles. The efficiency of SPS in producing compacts with low porosity might be dependent on the distribution of particle size in original powder material. The gas atomized Al7075 powder was sieved to several charges and then sintered by SPS. Microstructure of sintered compacts was studied by light and scanning electron microscopy. The phase composition was investigated using X-ray diffraction. The mechanical behaviour was tested by bending tests.

  17. Dusty plasma processes in Earth's polar summer mesosphere

    Science.gov (United States)

    Popel, S. I.; Dubinsky, A. Yu.; Dubinsky

    2013-08-01

    A self-consistent model for the description of dusty plasma structures, such as noctilucent clouds (NLC) and polar mesosphere summer echoes (PMSE), which are frequently grouped together under the common term polar mesospheric clouds, is presented. The model takes into account the processes of condensation of water vapor, ionization, recombination, action of solar radiation, sedimentation, dust particle growth, dust particle charging, electric fields, etc. Using the model, we explain the basic data of observations on the behavior of charged component in polar summer mesosphere. Furthermore, we show the influence of initial distributions of fine particles as well as that of the processes of condensation and water molecule absorption by fine particles on the formation of NLC and PMSE. We also illustrate the possibility of the formation of layered structure and sharp boundaries of NLC.

  18. Optimized process parameters for fabricating metal particles reinforced 5083 Al composite by friction stir processing.

    Science.gov (United States)

    Bauri, Ranjit; Yadav, Devinder; Shyam Kumar, C N; Janaki Ram, G D

    2015-12-01

    Metal matrix composites (MMCs) exhibit improved strength but suffer from low ductility. Metal particles reinforcement can be an alternative to retain the ductility in MMCs (Bauri and Yadav, 2010; Thakur and Gupta, 2007) [1,2]. However, processing such composites by conventional routes is difficult. The data presented here relates to friction stir processing (FSP) that was used to process metal particles reinforced aluminum matrix composites. The data is the processing parameters, rotation and traverse speeds, which were optimized to incorporate Ni particles. A wide range of parameters covering tool rotation speeds from 1000 rpm to 1800 rpm and a range of traverse speeds from 6 mm/min to 24 mm/min were explored in order to get a defect free stir zone and uniform distribution of particles. The right combination of rotation and traverse speed was found from these experiments. Both as-received coarse particles (70 μm) and ball-milled finer particles (10 μm) were incorporated in the Al matrix using the optimized parameters.

  19. Optimized process parameters for fabricating metal particles reinforced 5083 Al composite by friction stir processing

    Directory of Open Access Journals (Sweden)

    Ranjit Bauri

    2015-12-01

    Full Text Available Metal matrix composites (MMCs exhibit improved strength but suffer from low ductility. Metal particles reinforcement can be an alternative to retain the ductility in MMCs (Bauri and Yadav, 2010; Thakur and Gupta, 2007 [1,2]. However, processing such composites by conventional routes is difficult. The data presented here relates to friction stir processing (FSP that was used to process metal particles reinforced aluminum matrix composites. The data is the processing parameters, rotation and traverse speeds, which were optimized to incorporate Ni particles. A wide range of parameters covering tool rotation speeds from 1000 rpm to 1800 rpm and a range of traverse speeds from 6 mm/min to 24 mm/min were explored in order to get a defect free stir zone and uniform distribution of particles. The right combination of rotation and traverse speed was found from these experiments. Both as-received coarse particles (70 μm and ball-milled finer particles (10 μm were incorporated in the Al matrix using the optimized parameters.

  20. Solar Cluster: multipoint magnetic field and plasma parameter measurements in the solar wind

    Science.gov (United States)

    Vieira, L. E.; Echer, E.; dal Lago, A.; Schuch, N. J.

    This paper has the objective to discus the technical-scientific feasibility of a deep space mission to be proposed to the Brazilian Space Agency (AEB). This mission will be proposed to study the interplanetary magnetic field and the plasma structure of the solar wind. It will consist of a set of identical spacecraft flying in formation in the inner heliosphere during the ascending and maximum phase of the solar cycle 24. It is know that the primary cause of magnetic storms are intense, long duration southward interplanetary magnetic field structures which interconnect with the earth's magnetic field and allow solar wind energy transport into the Earth's magnetotail/magnetosphere. During the most active phase of the solar cycle, solar maximum, the sun's activity is dominated by flares and disappearing filaments, and their concomitant Coronal Mass Ejections (CMEs). Coronal Holes are present, but the holes are small and do not extend from the poles to the equator as often happens in the descending phase of the solar cycle. The fast (>500 km/s) CMEs coming from the sun into the interplanetary space are the solar/coronal features that contain high magnetic fields. These intense southward magnetic fields are observed in the sheath, in the ejection itself and in the rear of the ejection. The interaction between CMEs and the background solar wind, fast co rotating streams and other CMEs are also very important sources of intense southward magnetic fields. In order to study the interplanetary origin of intense geomagnetic storms, several studies have analyzed plasma parameters, composition, ionization state and the interplanetary magnetic field measured by instruments on board of spacecraft as ISEE3, IMP8, Helios, Ulysses, Wind, SOHO and ACE. Great advance on the understanding of the CME structure and interaction with the background solar wind have been reached. However, the spatial scale of these structures could be greater than 0.2 AU, and this kind of observation usually

  1. Theoretical study of nanoparticle formation in thermal plasma processing: Nucleation, coagulation and aggregation

    Science.gov (United States)

    Mendoza Gonzalez, Norma Yadira

    This work presents a mathematical modeling study of the synthesis of nanoparticles in radio frequency (RF) inductively coupled plasma (ICP) reactors. The purpose is to further investigate the influence of process parameters on the final size and morphology of produced particles. The proposed model involves the calculation of flow and temperature fields of the plasma gas. Evaporation of raw particles is also accounted with the particle trajectory and temperature history calculated with a Lagrangian approach. The nanoparticle formation is considered by homogeneous nucleation and the growth is caused by condensation and Brownian coagulation. The growth of fractal aggregates is considered by introducing a power law exponent Df. Transport of nanoparticles occurs by convection, thermophoresis and Brownian diffusion. The method of moments is used to solve the particle dynamics equation. The model is validated using experimental results from plasma reactors at laboratory scale. The results are presented in the following manner. First, use is made of the computational fluid dynamics software (CFD), Fluent 6.1 with a commercial companion package specifically developped for aerosols named: Fine Particle Model (FPM). This package is used to study the relationship between the operating parameters effect and the properties of the end products at the laboratory scale. Secondly, a coupled hybrid model for the synthesis of spherical particles and fractal aggregates is developped in place of the FPM package. Results obtained from this model will allow to identify the importance of each parameter in defining the morphology of spherical primary particles and fractal aggregates of nanoparticles. The solution of the model was made using the geometries and operating conditions of existing reactors at the Centre de Recherche en Energie, Plasma et Electrochimie (CREPE) of the Universite de Sherbrooke, for which experimental results were obtained experimentally. Additionally, this study

  2. Processing Parameters Influence on Wear Resistance Behaviour of Friction Stir Processed Al-TiC Composites

    Directory of Open Access Journals (Sweden)

    E. T. Akinlabi

    2014-01-01

    Full Text Available Friction stir processing (FSP being a novel process is employed for the improvement of the mechanical properties of a material and the production of surface layer composites. The vital role of the integrity of surface characteristics in the mechanical properties of materials has made the research studies into surface modification important in order to improve the performance in practical applications. This study investigates the effect of processing parameters on the wear resistance behavior of friction stir processed Al-TiC composites. This was achieved through microstructural characterization by using both the optical and scanning electron microscope (SEM, microhardness profiling, and tribological characterization by means of the wear. The microhardness profiling of the processed samples revealed an increased hardness value, which was a function of the TiC particles incorporated when compared to the parent material. The wear resistance property was also found to increase as a result of the TiC powder addition. The right combination of processing parameters was found to improve the wear resistance property of the composites produced.

  3. Multi responses optimization of wire EDM process parameters using ...

    African Journals Online (AJOL)

    International Journal of Engineering, Science and Technology .... considering input parameters peak current, pulse on time, pulse off time & wire tension for En31 tool steel ..... International Journal of Multidisciplinary and Current Research Vol.

  4. Optimization of process and solution parameters in electrospinning polyethylene oxide

    CSIR Research Space (South Africa)

    Jacobs, V

    2011-11-01

    Full Text Available , applied voltage and polyallylamine hydrochloride (PAH) concentration in the spinning solution and its influence on nanofiber diameter. The selected parameters were varied at three levels using Box and Behnken factorial design. The interaction effect...

  5. Analysis of suprathermal nuclear processes in the solar core plasma

    Science.gov (United States)

    Voronchev, Victor T.; Nakao, Yasuyuki; Watanabe, Yukinobu

    2017-04-01

    A consistent model for the description of suprathermal processes in the solar core plasma naturally triggered by fast particles generated in exoergic nuclear reactions is formulated. This model, based on the formalism of in-flight reaction probability, operates with different methods of treating particle slow-down in the plasma, and allows for the influence of electron degeneracy and electron screening on processes in the matter. The model is applied to examine slowing-down of 8.7 MeV α-particles produced in the {}7{Li}(p,α )α reaction of the pp chain, and to analyze suprathermal processes in the solar CNO cycle induced by them. Particular attention is paid to the suprathermal {}14{{N}}{(α ,{{p}})}17{{O}} reaction unappreciated in standard solar model simulations. It is found that an appreciable non-standard (α ,p) nuclear flow due to this reaction appears in the matter and modifies running of the CNO cycle in ∼95% of the solar core region. In this region at R> 0.1{R}ȯ , normal branching of nuclear flow {}14{{N}}≤ftarrow {}17{{O}}\\to {(}18{{F}})\\to {}18{{O}} transforms to abnormal sequential flow {}14{{N}}\\to {}17{{O}}\\to {(}18{{F}})\\to {}18{{O}}, altering some element abundances. In particular, nuclear network calculations reveal that in the outer core the abundances of 17O and 18O isotopes can increase by a factor of 20 as compared with standard estimates. A conjecture is made that other CNO suprathermal (α ,p) reactions may also affect abundances of CNO elements, including those generating solar neutrinos.

  6. Influence of processing parameters on lattice parameters in laser deposited tool alloy steel

    Energy Technology Data Exchange (ETDEWEB)

    Sun, G.F., E-mail: gfsun82@gmail.com [Center for Laser-Aided Intelligent Manufacturing, University of Michigan, Ann Arbor, MI, 48109 (United States); School of Mechanical Engineering, Jiangsu University, Zhenjiang, Jiangsu, 212013 (China); Bhattacharya, S. [Center for Laser-Aided Intelligent Manufacturing, University of Michigan, Ann Arbor, MI, 48109 (United States); Dinda, G.P.; Dasgupta, A. [Center for Advanced Technologies, Focus: Hope, Detroit, MI, 48238 (United States); Mazumder, J. [Center for Laser-Aided Intelligent Manufacturing, University of Michigan, Ann Arbor, MI, 48109 (United States)

    2011-06-15

    Highlights: {yields} Orientation relationships among phases in the DMD are given. {yields} Martensite lattice parameters increased with laser specific energy. {yields} Austenite lattice parameters decreased with laser specific energy. - Abstract: Laser aided direct metal deposition (DMD) has been used to form AISI 4340 steel coating on the AISI 4140 steel substrate. The microstructural property of the DMD coating was analyzed by means of scanning electron microscopy, transmission electron microscopy and X-ray diffractometry. Microhardness of the DMD was measured with a Vickers microhardness tester. Results indicate that DMD can be used to form dense AISI 4340 steel coatings on AISI 4140 steel substrate. The DMD coating is mainly composed of martensite and retained austenite. Consecutive thermal cycles have a remarkable effect on the microstructure of the plan view of the DMD coating and on the corresponding microhardness distribution. Orientation relationships among austenite, martensite and cementite in the DMD coating followed the ones in conventional heat treated steels. As the laser specific energy decreased, cooling rate increased, and martensite peaks broadened and shifted to a lower Bragg's angle. Also martensite lattice parameters increased and austenite lattice parameters decreased due to the above parameter change.

  7. Secondary electron emission from plasma processed accelerating cavity grade niobium

    Science.gov (United States)

    Basovic, Milos

    by different techniques. Specifically, this work provides the results of SEY from the plasma cleaned cavity grade niobium (Nb) samples. Pure niobium is currently the material of choice for the fabrication of Superconducting Radio Frequency (SRF) cavities. The effect of plasma processing with two different gases will be examined in two groups of samples. The first group of samples is made from cavity grade niobium. The second group of samples is made from the same material, but include a welded joint made by electron beam welding, since in niobium SRF cavities the peak electric and magnetic field are seen in close proximity to the welded joints. Both groups of samples will be exposed to nitrogen (N2) and a mixture of argon with oxygen (Ar/O2) plasma. It is the goal of this research to determine the SEY on these two groups of samples before and after plasma processing as a function of the energy of primary electrons. The SEY as a function of the angle of incidence of the primary electrons is tested on the samples treated with Ar/O2 plasma.

  8. Secondary Electron Emission from Plasma Processed Accelerating Cavity Grade Niobium

    Energy Technology Data Exchange (ETDEWEB)

    Basovic, Milos [Old Dominion Univ., Norfolk, VA (United States)

    2016-05-01

    by different techniques. Specifically, this work provides the results of SEY from the plasma cleaned cavity grade niobium (Nb) samples. Pure niobium is currently the material of choice for the fabrication of Superconducting Radio Frequency (SRF) cavities. The effect of plasma processing with two different gases will be examined in two groups of samples. The first group of samples is made from cavity grade niobium. The second group of samples is made from the same material, but include a welded joint made by electron beam welding, since in niobium SRF cavities the peak electric and magnetic field are seen in close proximity to the welded joints. Both groups of samples will be exposed to nitrogen (N2) and a mixture of argon with oxygen (Ar/O2) plasma. It is the goal of this research to determine the SEY on these two groups of samples before and after plasma processing as a function of the energy of primary electrons. The SEY as a function of the angle of incidence of the primary electrons is tested on the samples treated with Ar/O2 plasma.

  9. Form control in atmospheric pressure plasma processing of ground fused silica

    Science.gov (United States)

    Li, Duo; Wang, Bo; Xin, Qiang; Jin, Huiliang; Wang, Jun; Dong, Wenxia

    2014-08-01

    Atmospheric Pressure Plasma Processing (APPP) using inductively coupled plasma has demonstrated that it can achieve comparable removal rate on the optical surface of fused silica under the atmosphere pressure and has the advantage of inducing no sub-surface damage for its non-contact and chemical etching mechanism. APPP technology is a cost effective way, compared with traditional mechanical polishing, magnetorheological finishing and ion beam figuring. Thus, due to these advantages, this technology is being tested to fabricate large aperture optics of fused silica to help shorten the polishing time in optics fabrication chain. Now our group proposes to use inductively coupled plasma processing technology to fabricate ground surface of fused silica directly after the grinding stage. In this paper, form control method and several processing parameters are investigated to evaluate the removal efficiency and the surface quality, including the robustness of removal function, velocity control mode and tool path strategy. However, because of the high heat flux of inductively coupled plasma, the removal depth with time can be non-linear and the ground surface evolvement will be affected. The heat polishing phenomenon is founded. The value of surface roughness is reduced greatly, which is very helpful to reduce the time of follow-up mechanical polishing. Finally, conformal and deterministic polishing experiments are analyzed and discussed. The form error is less 3%, before and after the APPP, when 10μm depth of uniform removal is achieved on a 60×60mm ground fused silica. Also, a basin feature is fabricated to demonstrate the figuring capability and stability. Thus, APPP is a promising technology in processing the large aperture optics.

  10. A study of evolution/suppression parameters of equatorial postsunset plasma instability

    Directory of Open Access Journals (Sweden)

    O. S. Oyekola

    2009-01-01

    Full Text Available Evening equatorial pre-reversal vertical ion E×B drift (VZP and the peak of the ionospheric F2 maximum altitude (hmF2P of the postsunset equatorial F-layer, which are the essential parameters requisite for the generation or inhibition of postsunset bottomside equatorial irregularities were deduced from ionosonde observations made in the Africa region (Ouagadougou: ~3° N dip latitude between January 1987 and December 1990 for solar activity minimum, medium, and maxima (F10.7=85, 141, 214, and 190, respectively for quiet geomagnetic conditions. We investigate variations of evening equatorial pre-reversal drift and the corresponding altitude at four levels of solar activity. Our observations show strong variations with solar variability. Correlation analysis between these parameters indicates that the correlation coefficient value between hmF2P versus VZP decreases considerably with increasing solar flux value. There seems to be no significant link between these parameters under high solar activity, especially for solar intensity F10.7>200 units. We conclude that meridional neutral wind in the F-region contributes substantially to the variations of the pre-reversal vertical plasma drifts enhancement and the peak hmF2, particularly the electrodynamics during twilight high solar flux conditions.

  11. Adhesion properties of inverted polymer solarcells: Processing and film structure parameters

    KAUST Repository

    Dupont, Stephanie R.

    2013-05-01

    We report on the adhesion of weak interfaces in inverted P3HT:PCBM-based polymer solar cells (OPV) with either a conductive polymer, PEDOT:PSS, or a metal oxide, molybdenum trioxide (MoO3), as the hole transport layer. The PEDOT:PSS OPVs were prepared by spin or spray coating on glass substrates, or slot-die coating on flexible PET substrates. In all cases, we observed adhesive failure at the interface between the P3HT:PCBM with PEDOT:PSS layer. The adhesion energy measured for the solar cells made on glass substrates was about 1.8 J/m2, but only 0.5 J/m2 for the roll-to-roll processed flexible solar cells. The adhesion energy was insensitive to the PEDOT:PSS layer thickness in the range of 10-40 nm. A marginal increase in adhesion energy was measured with increased O2 plasma power. Compared to solution processed PEDOT:PSS, we found that thermally evaporated MoO 3 adheres less to the P3HT:PCBM layer, which we attributed to the reduced mixing at the MoO3/P3HT:PCBM interface during the thermal evaporation process. Insights into the mechanisms of delamination and the effect of different material properties and processing parameters yield general guidelines for the design of more reliable organic photovoltaic devices.© 2013 Elsevier B.V. All rights reserved.

  12. Sensor Data Acquisition and Processing Parameters for Human Activity Classification

    Directory of Open Access Journals (Sweden)

    Sebastian D. Bersch

    2014-03-01

    Full Text Available It is known that parameter selection for data sampling frequency and segmentation techniques (including different methods and window sizes has an impact on the classification accuracy. For Ambient Assisted Living (AAL, no clear information to select these parameters exists, hence a wide variety and inconsistency across today’s literature is observed. This paper presents the empirical investigation of different data sampling rates, segmentation techniques and segmentation window sizes and their effect on the accuracy of Activity of Daily Living (ADL event classification and computational load for two different accelerometer sensor datasets. The study is conducted using an ANalysis Of VAriance (ANOVA based on 32 different window sizes, three different segmentation algorithm (with and without overlap, totaling in six different parameters and six sampling frequencies for nine common classification algorithms. The classification accuracy is based on a feature vector consisting of Root Mean Square (RMS, Mean, Signal Magnitude Area (SMA, Signal Vector Magnitude (here SMV, Energy, Entropy, FFTPeak, Standard Deviation (STD. The results are presented alongside recommendations for the parameter selection on the basis of the best performing parameter combinations that are identified by means of the corresponding Pareto curve.

  13. Optical characteristics and parameters of gas-discharge plasma in a mixture of mercury dibromide vapor with argon

    Energy Technology Data Exchange (ETDEWEB)

    Malinina, A. A., E-mail: alexandr-malinin@rambler.ru; Malinin, A. N. [Uzhhorod National University (Ukraine)

    2015-03-15

    Results are presented from studies of the optical characteristics and parameters of the plasma of a dielectric barrier discharge in a mixture of mercury dibromide vapor with argon—the working medium of an exciplex gas-discharge emitter. It is established that the partial pressures of mercury dibromide vapor and argon at which the average and pulsed emission intensities in the blue—green spectral region (λ{sub max} = 502 nm) reach their maximum values are 0.6 and 114.4 kPa, respectively. The electron energy distribution function, the transport characteristics, the specific power spent on the processes involving electrons, the electron density and temperature, and the rate constants for the processes of elastic and inelastic electron scattering from the molecules and atoms of the working mixture are determined by numerical simulation, and their dependences on the reduced electric field strength are analyzed. The rate constant of the process leading to the formation of exciplex mercury monobromide molecules for a reduced electric field of E/N = 20 Td, at which the maximum emission intensity in the blue—green spectral region was observed in this experiment, is found to be 8.1 × 10{sup −15} m{sup 3}/s.

  14. Behavior of Plasma and Field Parameters and their Relationship with Geomagnetic Indices during Intense Geomagnetic Storms of Solar Cycle 23

    CERN Document Server

    Joshi, Navin Chandra; Pande, Seema; Pande, Bimal; Pandey, Kavita

    2010-01-01

    A correlative study between the geomagnetic indices and the peak values of various plasma and field parameters during rising, maximum and decay phases as well as during complete solar cycle 23 have been presented. We have also presented the lag/lead analysis between the maximum of Dst and peak values of plasma and field parameters and found that peak values of lag/lead time lies in the +/-10 hr interval. Three geomagnetic storms (GMSs) and associated solar sources observed during these phases of this solar cycle have also been studied and found that GMSs are associated with large flares and halo CMEs.

  15. Surface modification by electrolytic plasma processing for high Nb-TiAl alloys

    Science.gov (United States)

    Gui, Wanyuan; Hao, Guojian; Liang, Yongfeng; Li, Feng; Liu, Xiao; Lin, Junpin

    2016-12-01

    Metal surface modification by electrolytic plasma processing (EPP) is an innovative treatment widely commonly applied to material processing and pretreatment process of coating and galvanization. EPP involves complex processes and a great deal of parameters, such as preset voltage, current, solution temperature and processing time. Several characterization methods are presented in this paper for evaluating the micro-structure surfaces of Ti45Al8Nb alloys: SEM, EDS, XRD and 3D topography. The results showed that the oxide scale and other contaminants on the surface of Ti45Al8Nb alloys can be effectively removed via EPP. The typical micro-crater structure of the surface of Ti45Al8Nb alloys were observed by 3D topography after EPP to find that the mean diameter of the surface structure and roughness value can be effectively controlled by altering the processing parameters. The mechanical properties of the surface according to nanomechanical probe testing exhibited slight decrease in microhardness and elastic modulus after EPP, but a dramatic increase in surface roughness, which is beneficial for further processing or coating.

  16. Levels of oxidative stress biomarkers in seminal plasma and their relationship with seminal parameters

    Directory of Open Access Journals (Sweden)

    Zarghami Nosratollah

    2007-06-01

    Full Text Available Abstract Background There is growing evidence that damage to spermatozoa by reactive oxygen species (ROS play a key role in male infertility. The aim of the present study was to assess seminal plasma levels of total antioxidant capacity (TAC, free 8-Isoprostane and activities of catalase and superoxide dismutase (SOD in men with asthenozoospermia, asthenoteratozoospermia and oligoasthenoteratozoospermia compared with normozoospermic males. Methods The patients consisted of 46 men with seminal parameters abnormalities. The patients were grouped into asthenozoospermic (n = 15, asthenoteratozoospermic (n = 16 and oligoasthenoteratozoospermic (n = 15. The control group consisted of 16 healthy males with normozoospermia. Catalase activity was measured by Aebi spectrophotometeric method. Levels of TAC and SOD were measured by commercially available colorimetric assays. Level of free 8-Isoprostane was assessed by commercially available enzyme immunoassay (EIA method. Differences between groups were assessed using Mann-Whitney U test and Kruskal-Wallis test. Coefficients of correlation were calculated using Spearman's correlation analysis. All hypothesis tests were two-tailed with statistical significance assessed at the p value Results Levels of catalase and TAC were significantly lower in patients than the control group. No significant changes were seen in SOD activities. Levels of free 8-Isoprostane were significantly higher in patients than the control group. Furthermore, asthenozoospermic, asthenoteratozoospermic and oligoasthenoteratozoospermic groups had significantly lower values of catalase activity and TAC when compared to normozoospermic males. Levels of free 8-Isoprostane were significantly higher in all patients subgroups than the control group. Levels of catalase and TAC were positively correlated with sperm motility and morphology. Free 8-Isoprostane levels showed an inverse correlation with sperm motility and morphology. Conclusion

  17. Control of Groundwater Remediation Process as Distributed Parameter System

    Directory of Open Access Journals (Sweden)

    Mendel M.

    2014-12-01

    Full Text Available Pollution of groundwater requires the implementation of appropriate solutions which can be deployed for several years. The case of local groundwater contamination and its subsequent spread may result in contamination of drinking water sources or other disasters. This publication aims to design and demonstrate control of pumping wells for a model task of groundwater remediation. The task consists of appropriately spaced soil with input parameters, pumping wells and control system. Model of controlled system is made in the program MODFLOW using the finitedifference method as distributed parameter system. Control problem is solved by DPS Blockset for MATLAB & Simulink.

  18. Catalyst materials based on plasma-processed alumina nanopowder

    Directory of Open Access Journals (Sweden)

    Dubencovs Konstantins

    2012-01-01

    Full Text Available A platinum catalyst for glycerol oxidation by molecular oxygen has been developed applying the extractive-pyrolytic method and using, as a support, a fine alumina powder with an average particle size of 30-60 nm processed by plasma technology. The extractive-pyrolytic method (EPM allows affixing small amounts of catalytic metals (1-5% with the particle size ranging from several nanometers to several tens of nanometers onto the surface of the support. The prepared material - 4.8 wt. % platinum on nano-sized alumina - can be used as a catalyst for glycerol oxidation by oxygen with conversion up to 84%, in order to produce some organic acids (glyceric and lactic acid with a selectivity of about 60%.

  19. Dimension reduction of multivariable optical emission spectrometer datasets for industrial plasma processes.

    Science.gov (United States)

    Yang, Jie; McArdle, Conor; Daniels, Stephen

    2013-12-19

    A new data dimension-reduction method, called Internal Information Redundancy Reduction (IIRR), is proposed for application to Optical Emission Spectroscopy (OES) datasets obtained from industrial plasma processes. For example in a semiconductor manufacturing environment, real-time spectral emission data is potentially very useful for inferring information about critical process parameters such as wafer etch rates, however, the relationship between the spectral sensor data gathered over the duration of an etching process step and the target process output parameters is complex. OES sensor data has high dimensionality (fine wavelength resolution is required in spectral emission measurements in order to capture data on all chemical species involved in plasma reactions) and full spectrum samples are taken at frequent time points, so that dynamic process changes can be captured. To maximise the utility of the gathered dataset, it is essential that information redundancy is minimised, but with the important requirement that the resulting reduced dataset remains in a form that is amenable to direct interpretation of the physical process. To meet this requirement and to achieve a high reduction in dimension with little information loss, the IIRR method proposed in this paper operates directly in the original variable space, identifying peak wavelength emissions and the correlative relationships between them. A new statistic, Mean Determination Ratio (MDR), is proposed to quantify the information loss after dimension reduction and the effectiveness of IIRR is demonstrated using an actual semiconductor manufacturing dataset. As an example of the application of IIRR in process monitoring/control, we also show how etch rates can be accurately predicted from IIRR dimension-reduced spectral data.

  20. Subclinical hypocalcemia, plasma biochemical parameters, lipid metabolism, postpartum disease, and fertility in postparturient dairy cows.

    Science.gov (United States)

    Chamberlin, W G; Middleton, J R; Spain, J N; Johnson, G C; Ellersieck, M R; Pithua, P

    2013-01-01

    A study was conducted to evaluate the potential association between Ca status at calving and postpartum energy balance, liver lipid infiltration, disease occurrence, milk yield and quality parameters, and fertility in Holstein cows. One hundred cows were assigned to 1 of 2 groups based on whole-blood ionized Ca concentration ([iCa]) on the day of calving [d 0; hypocalcemic [iCa] Cows were blocked based on calving date and parity. Blood samples were collected approximately 14 d from expected calving date (d -14), the day of calving (d 0), and on d 3, 7, 14, 21, and 35 postpartum for measurement of plasma nonesterified fatty acid, iCa, total Ca, glucose, and total and direct bilirubin concentrations, and plasma aspartate aminotransferase and gamma glutamyl transferase activities. Liver biopsies were obtained from a subset of cows on d 0, 7, and 35 for quantification of lipid content. Milk samples were collected on d 3, 7, 14, 21, and 35 postpartum for measurement of somatic cell count and percentages of protein, fat, and solids-not-fat. Data for peak test-day milk yield, services per conception, and days open were obtained from Dairy Herd Improvement Association herd records. Disease occurrence was determined based on herd treatment records. Hypocalcemic cows had significantly higher nonesterified fatty acids on d 0. Hypocalcemic cows also had significantly more lipid in hepatocytes on d 7 and 35 postpartum. However, no statistically significant differences were observed between groups for plasma aspartate aminotransferase and gamma glutamyl transferase activities or total and direct bilirubin concentrations. Milk protein percentage was lower in hypocalcemic cows on d 21 and 35. However other milk quality variables (somatic cell count, milk fat percentage, and solids-not-fat) and milk yield variables (peak test-day milk yield and 305-d mature-equivalent 4% fat-corrected milk yield) did not differ between groups. No differences were observed between groups in the

  1. In vivo triglyceride synthesis in subcutaneous adipose tissue of humans correlates with plasma HDL parameters

    Science.gov (United States)

    Tuvdendorj, Demidmaa; Munoz, Alejandro O.; Ruiz-Barros, Viviana; Schwarz, Jean-Marc; Montalto, Giuseppe; Chandalia, Manisha; Sowers, Lawrence C.; Rizzo, Manfredi; Murphy, Elizabeth J; Abate, Nicola

    2016-01-01

    Backgrounds and aims Low concentrations of plasma HDL-C are associated with the development of atherosclerotic cardiovascular diseases and type 2 diabetes. Here we aimed to explore the relationship between the in vivo fractional synthesis of triglycerides (fTG) in subcutaneous (s.q.) abdominal adipose tissue (AT), HDL-C concentrations and HDL particle size composition in non-diabetic humans. Methods The fTG in s.q. abdominal AT was measured in 16 non-diabetic volunteers (7 women, 9 men; Age: 49±20 years; BMI: 31±5 kg/m; Fasting Plasma Glucose: 90±10 mg/dl) after 2H2O labeling. HDL-C concentration and subclasses, large (L-HDL), intermediate (I-HDL) and small (S-HDL) were measured. Results Linear regression analyses demonstrated significant associations of fTG with plasma concentration of HDL-C (r=0.625,p=0.009) and percent contribution of L-HDL (r=0.798,pHDL (r=−0.765,pHDL (r=−0.629, p=0.009). When analyses were performed by gender, the associations remained significant in women (HDL-C: r=0.822,p=0.023; L-HDL: r=0.892,p=0.007; I-HDL: r=−0.927,p=0.003) but not men. Conclusions Our study demonstrated an in vivo association between subcutaneous abdominal adipose tissue lipid dynamics and HDL parameters in humans, but this was true for women not men. Positive association with L-HDL and negative with I-HDL suggest that subcutaneous abdominal adipose tissue lipid dynamics may play an important role in production of mature functional HDL particles. Further studies evaluating the mechanism responsible for these associations and the observed gender differences are important and warranted to identify potential novel targets of intervention to increase the production of atheroprotective subclasses of HDL-Cs and thus decreasing the risks of development of atherosclerotic conditions. PMID:27323227

  2. The role of spatial confinement for improvement of laser-induced Mg plasma parameters and growth of surface features

    Science.gov (United States)

    Hayat, Asma; Bashir, Shazia; Rafique, Muhammad Shahid; Ahmad, Riaz; Akram, Mahreen; Mahmood, Khaliq; Zaheer, Ali

    2017-08-01

    The role of spatial confinement for improvement of laser-induced Mg plasma parameters and growth of surface features is investigated by introducing a metallic blocker. Nd: YAG laser at various fluences ranging from 7 to 28 J cm-2 was employed as an irradiation source. All measurements were performed in the presence of Ar under different pressures. Confinement effects offered by metallic blocker are investigated by placing the blocker at different distances of 6, 8 and 10 mm from the target surface. It is revealed from laser-induced breakdown spectroscopy analysis that both plasma parameters, i.e., excitation temperature and electron number density initially increase with increasing laser fluence due to enhancement in energy deposition. With further increase in laser fluence, a decreasing trend followed by saturation is observed which is attributable to shielding effect and self-regulating regime. It is also observed that spatial confinement offered by metallic blocker is responsible for the significant enhancement of both electron temperature and electron number density of Mg plasma. This is true for all laser fluences and pressures of Ar. Maximum values of electron temperature and electron number density without blocker are 8335 K and 2.4 × 1016 cm-3, respectively, whereas these values are enhanced to 12,200 K and 4 × 1016 cm-3 in the presence of the blocker. The physical mechanisms responsible for the enhancement of Mg plasma parameters are plasma compression, confinement and pronounced collisional excitations due to reflection of shock waves. Scanning electron microscope analysis was performed to explore the surface morphology of laser-ablated Mg. It reveals the formation of cones, cavities and ripples. These features become more distinct and well defined in the presence of the blocker due to plasma confinement. The optimum combination of blocker distance, fluence and Ar pressure can identify the suitable conditions for defining the role of plasma parameters

  3. Retrieval and processing of atmospheric parameters from satellite data

    Digital Repository Service at National Institute of Oceanography (India)

    Sathe, P.V.; Muraleedharan, P.M.

    Remote sensing of each of passive microwave channels enables one to estimate the atmospheric parameters over oceans on a repetitive basis throughout the year. Such a data base forms a useful tool in the study of complex weather phenomena. With India...

  4. Effect of Process Parameters on Porosity in Aluminum Lost Foam Process

    Institute of Scientific and Technical Information of China (English)

    Kiyoung KIM; Kyongwhoan LEE

    2005-01-01

    Porosity is a main defect in aluminum alloy castings, which is also thought to be severe in aluminum alloy castings produced by lost foam process due to the pyrolysis of the polystyrene foam pattern during pouring. Fundamental experiments were carried out to evaluate the effect of process parameters such as the melt treatment, the cooling rate and the density of expanded polystyrene (EPS) foam on porosity in A356.2 bar casting. The effect of melt treatment including degassing and refining was investigated. The effect of cooling rate was also evaluated by changing the mold packing material such as the silica sand, the zircon sand and the steel shots. Gas entrapment due to the turbulent metal flow during mold filling in conventional molding process results in porosity. Mold filling sequence in lost foam process is different from that in conventional molding process. The effect of molten metal flow was estimated by comparing the density of the casting by conventional sodium silicate molding with that by lost foam process. Density measurement was conducted to analyze the extent of porosity in the casting. Source of the porosity in lost foam process can be divided into two factors, i.e. turbulence in molten metal flow and entraining residue or gas from the pattern during pouring.

  5. Influence of the initial parameters of the magnetic field and plasma on the spatial structure of the electric current and electron density in current sheets formed in helium

    Energy Technology Data Exchange (ETDEWEB)

    Ostrovskaya, G. V., E-mail: galya-ostr@mail.ru [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation); Markov, V. S.; Frank, A. G., E-mail: annfrank@fpl.gpi.ru [Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation)

    2016-01-15

    The influence of the initial parameters of the magnetic field and plasma on the spatial structure of the electric current and electron density in current sheets formed in helium plasma in 2D and 3D magnetic configurations with X-type singular lines is studied by the methods of holographic interferometry and magnetic measurements. Significant differences in the structures of plasma and current sheets formed at close parameters of the initial plasma and similar configurations of the initial magnetic fields are revealed.

  6. Effects of Atomization Injection on Nanoparticle Processing in Suspension Plasma Spray

    Directory of Open Access Journals (Sweden)

    Hong-bing Xiong

    2016-05-01

    Full Text Available Liquid atomization is applied in nanostructure dense coating technology to inject suspended nano-size powder materials into a suspension plasma spray (SPS torch. This paper presents the effects of the atomization parameters on the nanoparticle processing. A numerical model was developed to simulate the dynamic behaviors of the suspension droplets, the solid nanoparticles or agglomerates, as well as the interactions between them and the plasma gas. The plasma gas was calculated as compressible, multi-component, turbulent jet flow in Eulerian scheme. The droplets and the solid particles were calculated as discrete Lagrangian entities, being tracked through the spray process. The motion and thermal histories of the particles were given in this paper and their release and melting status were observed. The key parameters of atomization, including droplet size, injection angle and velocity were also analyzed. The study revealed that the nanoparticle processing in SPS preferred small droplets with better atomization and less aggregation from suspension preparation. The injection angle and velocity influenced the nanoparticle release percentage. Small angle and low initial velocity might have more nanoparticles released. Besides, the melting percentage of nanoparticles and agglomerates were studied, and the critical droplet diameter to ensure solid melting was drawn. Results showed that most released nanoparticles were well melted, but the agglomerates might be totally melted, partially melted, or even not melted at all, mainly depending on the agglomerate size. For better coating quality, the suspension droplet size should be limited to a critical droplet diameter, which was inversely proportional to the cubic root of weight content, for given critical agglomerate diameter of being totally melted.

  7. Effect of basic physical parameters to control plasma meniscus and beam halo formation in negative ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Miyamoto, K. [Naruto University of Education, 748 Nakashima, Takashima, Naruto-cho, Naruto-shi, Tokushima 772-8502 (Japan); Okuda, S.; Nishioka, S.; Hatayama, A. [Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan)

    2013-09-14

    Our previous study shows that the curvature of the plasma meniscus causes the beam halo in the negative ion sources: the negative ions extracted from the periphery of the meniscus are over-focused in the extractor due to the electrostatic lens effect, and consequently become the beam halo. In this article, the detail physics of the plasma meniscus and beam halo formation is investigated with two-dimensional particle-in-cell simulation. It is shown that the basic physical parameters such as the H{sup −} extraction voltage and the effective electron confinement time significantly affect the formation of the plasma meniscus and the resultant beam halo since the penetration of electric field for negative ion extraction depends on these physical parameters. Especially, the electron confinement time depends on the characteristic time of electron escape along the magnetic field as well as the characteristic time of electron diffusion across the magnetic field. The plasma meniscus penetrates deeply into the source plasma region when the effective electron confinement time is short. In this case, the curvature of the plasma meniscus becomes large, and consequently the fraction of the beam halo increases.

  8. Influence of Process Parameters on Nitrogen Oxide Formation in

    DEFF Research Database (Denmark)

    Lans, Robert Pieter Van Der; Glarborg, Peter; Dam-Johansen, Kim

    1997-01-01

    This paper describes the influence of burner operating conditions, burner geometry and fuel parameters on the formation of nitrogen oxide during combustion of pulverized coal. Main attention has been paid to combustion test facilities with self-sustaining flames, while extensions have been made...... to full scale boilers and furnace modeling. Since coal combustion and flame aerodynamics have been reviewed earlier, these phenomena are only treated briefly....

  9. Updating parameters of the chicken processing line model

    DEFF Research Database (Denmark)

    Kurowicka, Dorota; Nauta, Maarten; Jozwiak, Katarzyna

    2010-01-01

    A mathematical model of chicken processing that quantitatively describes the transmission of Campylobacter on chicken carcasses from slaughter to chicken meat product has been developed in Nauta et al. (2005). This model was quantified with expert judgment. Recent availability of data allows...... of the chicken processing line model....

  10. Experimental measurements of the hollow cathode DC glow discharge parameters in Ar and He plasmas

    Science.gov (United States)

    Omrani, M.; Amrollahi, R.; Iraji, D.

    2016-12-01

    In this article, we focus on some of the fundamental parameters of SS316L hollow cathode glow discharge. Four SS316L samples are placed at different locations on the cathode surface and the current passed through them is measured in Ar and He glow discharge plasmas. The wall current densities of Ar and He are in the range of 8-25 µA cm-2 and 8-35 µA cm-2, respectively. Results also show that with decreasing working pressure, the ion flux and current density distribution on the wall surface becomes more uniform. The ion flux of the Ar and He is in the range of 1013 to 1014 ~\\text{ion} \\text{c}{{\\text{m}}-2} . Total energy losses of Ar and He are measured at the pressure range of 1.4-5.5  ×  10-2 torr and 3.2-7.1  ×  10-1, respectively. In both Ar and He, total energy losses decreased with increasing pressure. The secondary electron emission coefficients of Ar and He, which are evaluated for the hallow cathode configuration, are about 0.42 and 0.26, respectively, and are higher in comparison with the plate cathode configuration.

  11. Effect of dietary protein sources on production performance, egg quality, and plasma parameters of laying hens

    Science.gov (United States)

    Wang, Xiaocui; Zhang, Haijun; Wang, Hao; Wang, Jing; Wu, Shugeng; Qi, Guanghai

    2017-01-01

    Objective This study was conducted to evaluate the effects of dietary protein sources (soybean meal, SBM; low-gossypol cottonseed meal, LCSM; double-zero rapeseed meal, DRM) on laying performance, egg quality, and plasma parameters of laying hens. Methods A total of 432 32-wk-old laying hens were randomly divided into 6 treatments with 6 replicates of 12 birds each. The birds were fed diets containing SBM, LCSM100, or DRM100 individually or in combination with an equal amount of crude protein (CP) (LCSM50, DRM50, and LCSM50-DRM50). The experimental diets, which were isocaloric (metabolizable energy, 11.11 MJ/kg) and isonitrogenous (CP, 16.5%), had similar digestible amino acid profile. The feeding trial lasted 12 weeks. Results The daily egg mass was decreased in the LCSM100 and LCSM50-DRM50 groups (p0.05) and showed increased yolk color at the end of the trial (p0.05). Conclusion Together, our results suggest that the LCSM100 or DRM100 diets may produce the adverse effects on laying performance and egg quality after feeding for 8 more weeks. The 100.0 g/kg LCSM diet or the148.7 g/kg DRM diet has no adverse effects on laying performance and egg quality. PMID:27608634

  12. Production of stable isotopes utilizing the plasma separation process

    Science.gov (United States)

    Bigelow, T. S.; Tarallo, F. J.; Stevenson, N. R.

    2005-12-01

    A plasma separation process (PSP) is being operated at Theragenics Corporation's®, Oak Ridge, TN, facility for the enrichment of stable isotopes. The PSP utilizes ion cyclotron mass discrimination to separate isotopes on a relatively large scale. With a few exceptions, nearly any metallic element could be processed with PSP. Output isotope enrichment factor depends on natural abundance and mass separation and can be fairly high in some cases. The Theragenics™ PSP facility is believed to be the only such process currently in operation. This system was developed and formerly operated under the US Department of Energy Advanced Isotope Separation program. Theragenics™ also has a laboratory at the PSP site capable of harvesting the isotopes from the process and a mass spectrometer system for analyzing enrichment and product purity. Since becoming operational in 2002, Theragenics™ has utilized the PSP to separate isotopes of several elements including: dysprosium, erbium, gadolinium, molybdenum and nickel. Currently, Theragenics™ is using the PSP for the separation of 102Pd, which is used as precursor for the production of 103Pd. The 103Pd radioisotope is the active ingredient in TheraSeed®, which is used in the treatment of early stage prostate cancer and being investigated for other medical applications. New industrial, medical and research applications are being investigated for isotopes that can be enriched on the PSP. Pre-enrichment of accelerator or reactor targets offers improved radioisotope production. Theragenics operates 14 cyclotrons for proton activation and has access to HFIR at ORNL for neutron activation of radioisotopes.

  13. Plasma parameters in the vicinity of the quartz window of a low pressure surface wave discharge produced in O2

    DEFF Research Database (Denmark)

    Nakao, S.; Stamate, Eugen; Sugai, H.

    2007-01-01

    Plasma parameters in the vicinity of the dielectric window of a low density, microwave discharge produced in 0, at 915 N/FHz are investigated by a spherical probe and optical emission spectroscopy while the microwave field distribution is measured by a spectrum analyzer. The electron energy...

  14. Thermal compression chip interconnection using organic solderability preservative etched substrate by plasma processing.

    Science.gov (United States)

    Cho, Sung-Won; Choi, JoonYoung; Chung, Chin-Wook

    2014-12-01

    The solderability of copper organic solderbility preservative (CuOSP) finished substrate was enhanced by the plasma etching. To improve the solderability of TC interconnection with the CuOSP finished substrate, the plasma etching process is used. An Oxygen-Hydrogen plasma treatment process is performed to remove OSP material. To prevent the oxidation by oxygen plasma treatment, hydrogen reducing process is also performed before TC interconnection process. The thickness of OSP material after plasma etching is measured by optical reflection method and the component analysis by Auger Electron Spectroscopy is performed. From the lowered thickness, the bonding force of TC interconnection after OSP etching process is lowered. Also the electrical open/short test was performed after assembling the completed semiconductor packaging. The improved yield due to the plasma etching process is achieved.

  15. Research progress of laser welding process dynamic monitoring technology based on plasma characteristics signal

    Directory of Open Access Journals (Sweden)

    Teng WANG

    2017-02-01

    Full Text Available During the high-power laser welding process, plasmas are induced by the evaporation of metal under laser radiation, which can affect the coupling of laser energy and the workpiece, and ultimately impact on the reliability of laser welding quality and process directly. The research of laser-induced plasma is a focus in high-power deep penetration welding field, which provides a promising research area for realizing the automation of welding process quality inspection. In recent years, the research of laser welding process dynamic monitoring technology based on plasma characteristics is mainly in two aspects, namely the research of plasma signal detection and the research of laser welding process modeling. The laser-induced plasma in the laser welding is introduced, and the related research of laser welding process dynamic monitoring technology based on plasma characteristics at home and abroad is analyzed. The current problems in the field are summarized, and the future development trend is put forward.

  16. Plasma protein-binding parameters of prednisolone in immune disease patients receiving long-term prednisone therapy.

    Science.gov (United States)

    Wagner, J G; Wexler, D; Ağabeyoğlu, I T; Bergstrom, R F; Sakmar, E; Kay, D R

    1981-04-01

    Prednisone and prednisolone bind in plasma to albumin and transcortin. In am attempt to determine whether prednisone side effects and/or type of disease correlated with prednisolone plasma protein binding, multiple plasma samples from 17 patients (three asthma, eight SLE, three RA, two PSS, one PAN) receiving long-term prednisone therapy were monitored during an interval between two prednisone doses. Prednisolone plasma protein binding was nonlinear and exhibited large intrapatient and interpatient variability. For the group, mean association constants of the prednisolone-albumin complex and the prednisolone-transcortin complex were 2.3 X 10(3) M-1 and 2.9 X 10(7) M-1, with coefficients of variation of 82% and 127%, respectively. SLE patients tended to have lower mean prednisolone association constants for albumin and transcortin than did other patients. The presence of corticosteroid side effects did not correlate with prednisolone plasma protein-binding parameters. The wide range of prednisolone free fraction noted in plasma from patients who achieved comparable total prednisolone plasma concentrations implies that administration of a uniform prednisone dose will not lead to a predictable clinical response.

  17. NUMERICAL SIMULATION OF RESIDUAL STRESSES GENERATED IN THE WIRE DRAWING PROCESS FOR DIFFERENT PROCESS PARAMETERS

    Directory of Open Access Journals (Sweden)

    Juliana Zottis

    2014-03-01

    Full Text Available The drawing process of steel bars is usually used to check better dimensional accuracy and mechanical properties to the material. In the other hand, the major concern found in manufacturing axes through this process is the appearance of distortion of shape. Such distortions are directly linked to the accumulation of residual stresses generated during the processes. As a result, this paper aims to study the influence of process parameters such as shape of puller, speed and lubrication used in wire drawing analyzing the accumulation of residual stress after the process. The stress analysis was performed by FEM being used two simulation software: Simufact.formingGP and DeformTM. Through these analyzes, it was found that the shape of how the bar is pulled causes a reduction of up to 100 MPa in residual stresses in the center of the bar, which represents an important factor in the study of the possible causes of the distortion. As well as factors speed and homogeneity of lubrication significantly altered the profile of residual stresses in the bar.

  18. A study of process parameters on workpiece anisotropy in the laser engineered net shaping (LENSTM) process

    Science.gov (United States)

    Chandra, Shubham; Rao, Balkrishna C.

    2017-06-01

    The process of laser engineered net shaping (LENSTM) is an additive manufacturing technique that employs the coaxial flow of metallic powders with a high-power laser to form a melt pool and the subsequent deposition of the specimen on a substrate. Although research done over the past decade on the LENSTM processing of alloys of steel, titanium, nickel and other metallic materials typically reports superior mechanical properties in as-deposited specimens, when compared to the bulk material, there is anisotropy in the mechanical properties of the melt deposit. The current study involves the development of a numerical model of the LENSTM process, using the principles of computational fluid dynamics (CFD), and the subsequent prediction of the volume fraction of equiaxed grains to predict process parameters required for the deposition of workpieces with isotropy in their properties. The numerical simulation is carried out on ANSYS-Fluent, whose data on thermal gradient are used to determine the volume fraction of the equiaxed grains present in the deposited specimen. This study has been validated against earlier efforts on the experimental studies of LENSTM for alloys of nickel. Besides being applicable to the wider family of metals and alloys, the results of this study will also facilitate effective process design to improve both product quality and productivity.

  19. Effect of Processing Conditions on the Anelastic Behavior of Plasma Sprayed Thermal Barrier Coatings

    Science.gov (United States)

    Viswanathan, Vaishak

    2011-12-01

    Plasma sprayed ceramic materials contain an assortment of micro-structural defects, including pores, cracks, and interfaces arising from the droplet based assemblage of the spray deposition technique. The defective architecture of the deposits introduces a novel "anelastic" response in the coatings comprising of their non-linear and hysteretic stress-strain relationship under mechanical loading. It has been established that this anelasticity can be attributed to the relative movement of the embedded defects under varying stresses. While the non-linear response of the coatings arises from the opening/closure of defects, hysteresis is produced by the frictional sliding among defect surfaces. Recent studies have indicated that anelastic behavior of coatings can be a unique descriptor of their mechanical behavior and related to the defect configuration. In this dissertation, a multi-variable study employing systematic processing strategies was conducted to augment the understanding on various aspects of the reported anelastic behavior. A bi-layer curvature measurement technique was adapted to measure the anelastic properties of plasma sprayed ceramic. The quantification of anelastic parameters was done using a non-linear model proposed by Nakamura et.al. An error analysis was conducted on the technique to know the available margins for both experimental as well as computational errors. The error analysis was extended to evaluate its sensitivity towards different coating microstructure. For this purpose, three coatings with significantly different microstructures were fabricated via tuning of process parameters. Later the three coatings were also subjected to different strain ranges systematically, in order to understand the origin and evolution of anelasticity on different microstructures. The last segment of this thesis attempts to capture the intricacies on the processing front and tries to evaluate and establish a correlation between them and the anelastic

  20. Effects of Dietary Supplementation of Some Antioxidants on Liver Antioxidant Status and Plasma Biochemistry Parameters of Heat-Stressed Quail

    Directory of Open Access Journals (Sweden)

    Senay Sarıca

    2017-07-01

    Full Text Available This study aimed to compare the dietary supplementation of oleuropein (O and α-tocopherol acetate (TA alone or with organic selenium (Se on liver antioxidant status and some plasma biochemistry parameters in Japanese quails reared under heat stress (HS. A total of 800, two-weeks old quails were kept in wire cages in the temperature-controlled rooms at either 22°C or 34°C for 8 h/d and fed on a basal diet (NC or the diets supplemented with TA (TA200 or O (O200 at 200 mg/kg alone or with OSe (TA200+OSe and O200+OSe to the NC diet. HS decreased the total antioxidant status (TAS and increased the total oxidative stress (TOS and oxidative stress index (OSI of liver compared to thermoneutral temperature (TN. The TA200, O200, TA200+OSe and O200+OSe diets increased TAS and decreased TOS of liver compared to those of quails fed NC. OSI was decreased by the TA200, O200 and TA200+OSe diets compared to NC and O200+OSe diets. HS reduced plasma albumin (A and total protein (TP concentrations, on the other hand, increased plasma glucose (G, total cholesterol (CHO and triglyceride (TG levels compared to TN. The TA200, O200, TA200+OSe and O200+OSe diets reduced plasma total CHO and TG levels and increased plasma A level. The TA200 and TA200+OSe diets reduced plasma G level and increased plasma TP levels compared to those of quails fed the other diets. In conclusion, dietary supplementation of vitamin E and oleuropein alone or with organic selenium is necessary to remove the negative effects of heat stress on liver antioxidant status and some plasma parameters of quails.

  1. Determining the optimum process parameter for grinding operations using robust process

    Energy Technology Data Exchange (ETDEWEB)

    Neseli, Suley Man; Asilturk, Ilhan; Celik, Levent [Univ. of Selcuk, Konya (Turkmenistan)

    2012-11-15

    We applied combined response surface methodology (RSM) and Taguchi methodology (TM) to determine optimum parameters for minimum surface roughness (Ra) and vibration (Vb) in external cylindrical grinding. First, an experiment was conducted in a CNC cylindrical grinding machine. The TM using L{sup 27} orthogonal array was applied to the design of the experiment. The three input parameters were workpiece revolution, feed rate and depth of cut; the outputs were vibrations and surface roughness. Second, to minimize wheel vibration and surface roughness, two optimized models were developed using computer aided single objective optimization. The experimental and statistical results revealed that the most significant grinding parameter for surface roughness and vibration is workpiece revolution followed by the depth of cut. The predicted values and measured values were fairly close, which indicates 2 ( 94.99 R{sup 2Ra}=and 2 92.73) R{sup 2Vb}=that the developed models can be effectively used to predict surface roughness and vibration in the grinding. The established model for determination of optimal operating conditions shows that a hybrid approach can lead to success of a robust process.

  2. Imaging of the Staphylococcus aureus Inactivation Process Induced by a Multigas Plasma Jet.

    Science.gov (United States)

    Takamatsu, Toshihiro; Kawano, Hiroaki; Sasaki, Yota; Uehara, Kodai; Miyahara, Hidekazu; Matsumura, Yuriko; Iwasawa, Atsuo; Azuma, Takeshi; Okino, Akitoshi

    2016-12-01

    To identify mechanisms underlying the bacterial inactivation process by atmospheric nonthermal plasma using a unique plasma jet that can generate various gas plasmas, Staphylococcus aureus were irradiated with carbon dioxide plasma, which produces a large amount of singlet oxygens, and nitrogen plasma, which produces a large amount of OH radicals. And damaged areas of plasma-treated bacteria were observed by field emission scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. As a result, bacteria were damaged by both gas plasmas, but the site of damage differed according to gas species. Therefore, it suggests that singlet oxygen generated by carbon dioxide plasma or other reactive species caused by singlet oxygen contributes to the damage of internal structures of bacteria through the cell wall and membrane, and OH radicals generated by nitrogen plasma or other reactive species derived from OH radicals contribute to damage of the cell wall and membrane.

  3. OPTIMIZATION OF PROCESSING PARAMETERS DURING ISM PROCESS OF Ti-15-3

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Based on the direct finite difference method, a numerical model for simulating the temperature field in the charge during Induction Skull Melting (ISM) process has been developed. By use of the simulation program, the temperature field in the charge of Ti-15V-3Cr-3Sn-3Al(Ti-15-3) has been calculated under the condition of various melting powers and charge weights. Furthermore, the relationship between the ultimate temperature in the melt and the melting power, charge weight has been set up. On the basis of the relationship, the parameters during the ISM process of Ti-15-3 (the principle is adaptable to other titanium alloys) would be optimized, consequently, much man-power and finance would be saved and the quality of the melt would be improved.

  4. Transferred plasma jet from a dielectric barrier discharge for processing of poly(dimethylsiloxane) surfaces

    CERN Document Server

    Nascimento, Fellype do; Canesqui, Mara A; Moshkalev, Stanislav

    2016-01-01

    In this work we studied processing of poly(dimethylsiloxane) (PDMS) surfaces using dielectric barrier discharge (DBD) plasma in two different assemblies, one using the primary plasma jet obtained from a conventional DBD and the other using a DBD plasma jet transfer. The evolution of water contact angle (WCA) in function of plasma processing time and in function of aging time as well as the changes in the surface roughness of PDMS samples for both plasma treatments have been studied. We also compared vibrational and rotational temperatures for both plasmas and for the first time the vibrational temperature (T_vib) for the transferred plasma jet has been shown to be higher as compared with the primary jet. The increment in the T_vib value seems to be the main reason for the improvements in adhesion properties and surface wettability for the transferred plasma jet. Possible explanations for the increase in the vibrational temperature are presented.

  5. Statistics on the parameters of nonisothermal ionospheric plasma in large mesospheric electric fields

    Science.gov (United States)

    Martynenko, S.; Rozumenko, V.; Tyrnov, O.; Manson, A.; Meek, C.

    The large V/m electric fields inherent in the mesosphere play an essential role in lower ionospheric electrodynamics. They must be the cause of large variations in the electron temperature and the electron collision frequency at D region altitudes, and consequently the ionospheric plasma in the lower part of the D region undergoes a transition into a nonisothermal state. This study is based on the databases on large mesospheric electric fields collected with the 2.2-MHz radar of the Institute of Space and Atmospheric Studies, University of Saskatchewan, Canada (52°N geographic latitude, 60.4°N geomagnetic latitude) and with the 2.3-MHz radar of the Kharkiv V. Karazin National University (49.6°N geographic latitude, 45.6°N geomagnetic latitude). The statistical analysis of these data is presented in Meek, C. E., A. H. Manson, S. I. Martynenko, V. T. Rozumenko, O. F. Tyrnov, Remote sensing of mesospheric electric fields using MF radars, Journal of Atmospheric and Solar-Terrestrial Physics, in press. The large mesospheric electric fields is experimentally established to follow a Rayleigh distribution in the interval 0 processes coupling the electrically active mesosphere and the lower ionospheric plasma.

  6. Influence of laser design parameters on the hydrodynamics of microfusion plasmas; Influencia de los parametros basicos del laser sobre la hidrodinamica de plasmas para microfusion

    Energy Technology Data Exchange (ETDEWEB)

    Sanmartin, J. A.; Barrero, A.

    1976-07-01

    The quasi neutral, one dimensional motion generated in a cold, infinite, uniform plasma of density n{sub 0}, by the absorption, In a given plane, of a linear pulse of energy per unit time and area {phi} - {phi}{sub 0}t/{tau}, 0< t {<=} {tau}, is considered; the analysis allows for thermal conduction and viscosity of ions and electrons, their energy exchange, and an electron thermal flux limiter. The motion is found to be self similar and governed by single non dimensional parameter {alpha} similar{sub t}o(n{sup 2}{sub 0} {tau}/{phi}{sub 0}){sup 2}/3. Detailed asymptotic results are obtained for both {alpha}<<1and {alpha}>>1; the general (behaviour of the solution for arbitrary {alpha} is discussed. The analysis can be easily extended to the case of a plasma initially occupying a half-space, and throws light on the hydrodynamics of laser fusion plasmas. (Author) 51 refs.

  7. Imploding process and x-ray emission of shotgun z-pinch plasma

    Energy Technology Data Exchange (ETDEWEB)

    Muto, Ryusuke [Nihon University, College of Science and Technology, Tokyo (Japan); Takasugi, Keiichi; Miyamoto, Tetsu [Nihon University, Atomic Energy Research Institute, Tokyo (Japan)

    2001-09-01

    Rayleigh-Taylor instability was observed on the surface of a contracting z-pinch plasma. Wavelength of the instability was analyzed from the envelope of the profile, and it increased with implosion. Analysis with finite Larmor radius effect shows that there is some acceleration of ions during the contraction process. A suggestion to obtain macroscopically uniform plasma is to increase plasma current without heating the plasma. (author)

  8. Numerical simulation of chemical processes in helium plasmas in atmosphere environment

    Institute of Scientific and Technical Information of China (English)

    欧阳建明; 郭伟; 王龙; 邵福球

    2005-01-01

    A model is built to study chemical processes in plasmas generated in helium with trace amounts of air at atmospheric pressure or low pressures. The plasma lifetimes and the temporal evolutions of the main charged species are presented. The plasma lifetimes are longer than that in air plasma at atmospheric pressure, but this is not true at low pressures. The electron number density does not strictly obey the exponential damping law in a longer period.

  9. Effect of the initial plasma parameters on the structure of the current sheets developing in two-dimensional magnetic fields with a null line

    Science.gov (United States)

    Ostrovskaya, G. V.; Frank, A. G.; Bogdanov, S. Yu.

    2010-07-01

    The effect of the initial plasma parameters on the structure of the plasma of the current sheets that form in two-dimensional magnetic fields with a null line is studied by holographic interferometry. The evolution of the plasma sheets that develop in an initial low-density plasma, where a gas is mainly ionized by a pulse current passing through the plasma and initiating the formation of a current sheet, has been comprehensively studied for the first time. At the early stage of evolution, the spatial structure of such a plasma sheet differs substantially from the classic current sheets forming in a dense plasma. Nevertheless, extended plasma sheets with similar parameters form eventually irrespective of the initial plasma density.

  10. Optimization Of Pulsed Current Parameters To Minimize Pitting Corrosion İn Pulsed Current Micro Plasma Arc Welded Aısı 304l Sheets Using Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Kondapalli Siva Prasad

    2013-06-01

    Full Text Available Austenitic stainless steel sheets have gathered wide acceptance in the fabrication of components, which require high temperature resistance and corrosion resistance, such as metal bellows used in expansion joints in aircraft, aerospace and petroleum industry. In case of single pass welding of thinner sections of this alloy, Pulsed Current Micro Plasma Arc Welding (PCMPAW was found beneficial due to its advantages over the conventional continuous current process. This paper highlights the development of empirical mathematical equations using multiple regression analysis, correlating various process parameters to pitting corrosion rates in PCMPAW of AISI 304L sheets in 1 Normal HCl. The experiments were conducted based on a five factor, five level central composite rotatable design matrix. A Genetic Algorithm (GA was developed to optimize the process parameters for minimizing the pitting corrosion rates.

  11. Liquid Feedstock Plasma Spraying: An Emerging Process for Advanced Thermal Barrier Coatings

    Science.gov (United States)

    Markocsan, Nicolaie; Gupta, Mohit; Joshi, Shrikant; Nylén, Per; Li, Xin-Hai; Wigren, Jan

    2017-08-01

    Liquid feedstock plasma spraying (LFPS) involves deposition of ultrafine droplets of suspensions or solution precursors (typically ranging from nano- to submicron size) and permits production of coatings with unique microstructures that are promising for advanced thermal barrier coating (TBC) applications. This paper reviews the recent progress arising from efforts devoted to development of high-performance TBCs using the LFPS approach. Advancements in both suspension plasma spraying and solution precursor plasma spraying, which constitute the two main variants of LFPS, are presented. Results illustrating the different types of the microstructures that can be realized in LFPS through appropriate process parameter control, model-assisted assessment of influence of coating defects on thermo-mechanical properties and the complex interplay between pore coarsening, sintering and crystallite growth in governing thermal conductivity are summarized. The enhancement in functional performances/lifetime possible in LFPS TBCs with multilayered architectures and by incorporating new pyrochlore chemistries such as gadolinium zirconate, besides the conventional single 8 wt.% yttria-stabilized zirconia insulating ceramic layer, is specifically highlighted.

  12. Thermal plasma processed ferro-magnetically ordered face-centered cubic iron at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Raut, Suyog A.; Kanhe, Nilesh S.; Bhoraskar, S. V.; Mathe, V. L., E-mail: vlmathe@physics.unipune.ac.in [Department of Physics, Savitribai Phule Pune University, Pune 411007 (India); Das, A. K. [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

    2014-10-28

    Here, we report tailor made phase of iron nanoparticles using homogeneous gas phase condensation process via thermal plasma route. It was observed that crystal lattice of nano-crystalline iron changes as a function of operating parameters of the plasma reactor. In the present investigation iron nanoparticles have been synthesized in presence of argon at operating pressures of 125–1000 Torr and fixed plasma input DC power of 6 kW. It was possible to obtain pure fcc, pure bcc as well as the mixed phases for iron nanoparticles in powder form as a function of operating pressure. The as synthesized product was characterized for understanding the structural and magnetic properties by using X-ray diffraction, vibrating sample magnetometer, and Mössbauer spectroscopy. The data reveal that fcc phase is ferromagnetically ordered with high spin state, which is unusual whereas bcc phase is found to be ferromagnetic as usual. Finally, the structural and magnetic properties are co-related.

  13. Effects of the Process Parameters on Austenitic Stainless Steel by TIG-Flux Welding

    Institute of Scientific and Technical Information of China (English)

    Heryueh HUANG; Shengwen SHYU; Kuanghung TSENG; Changpin CHOU

    2006-01-01

    The effects of the process parameters of TIG (tungsten inset gas)-flux welding on the welds morphology,angular distortion, ferrite content and hot cracking in austenitic stainless steel were investigated. Autogenous TIG welding process was applied to the type 304 stainless steel through a thin layer of activating flux to produce a bead on plate welded joint. TiO2, SiO2, Fe2O3, Cr2O3, ZnO and MnO2 were used as the activating fluxes. The experimental results indicated that the TIG-flux welding can increase the weld depth/width ratio and reduce the HAZ (heat affected zone) range, and therefore the angular distortion of the weldment can be reduced. It was also found that the retained ferrite content within the TIG-flux welds is increased, and has a beneficial effect in reducing hot cracking tendency for stainless steels of the austenitic type weld metals. A plasma column constriction increases the current density at the anode spot and then a substantial increase in penetration of the TIG-flux welds can be obtained.

  14. Manufacturing of anode supported SOFCs: Processing parameters and their influence

    DEFF Research Database (Denmark)

    Ramousse, Severine; Menon, Mohan; Brodersen, Karen;

    2007-01-01

    The establishment of low cost, highly reliable and reproducible manufacturing processes has been focused for commercialization of SOFC technology. A major challenge in the production chain is the manufacture of anode-supported planar SOFC's single cells in which each layer in a layered structure ...

  15. Sensitivity analysis on parameters and processes affecting vapor intrusion risk

    NARCIS (Netherlands)

    Picone, S.; Valstar, J.R.; Gaans, van P.; Grotenhuis, J.T.C.; Rijnaarts, H.H.M.

    2012-01-01

    A one-dimensional numerical model was developed and used to identify the key processes controlling vapor intrusion risks by means of a sensitivity analysis. The model simulates the fate of a dissolved volatile organic compound present below the ventilated crawl space of a house. In contrast to the v

  16. Measuring the parameters of a high flux plasma in Proto-MPEX

    Science.gov (United States)

    Skeen, C.; Biewer, T. M.; Cantrell, C. L.; Klemm, J. C.; Musick, R. A.; Nunley, G.; Salazar Sanchez, J. S.; Sawyer, D. J.; Ray, H.; Shaw, G.; Showers, M.

    2016-10-01

    The Prototype Material Plasma Exposure Experiment (Proto-MPEX) is a linear, magnetically confined plasma production device, utilizing a helicon antenna. The plasma column interacts with a material target at the end of the device, creating plasma-material interaction conditions that are relevant to the conditions that are expected in future fusion reactors. Moreover, helicon antenna plasma sources have been proposed as propulsion devices for spacecraft. It has been observed that in some circumstances the Proto-MPEX plasma exerts sufficient force on the target plate to cause the target to recoil. A ballistic probe has been designed to measure the force and heat flux profile of the plasma. The probe response has been calibrated, using scales, thermocouples, and fast camera imaging. The ballistic probe has been inserted into Proto-MPEX plasmas and the heat flux profile of the plasma has been measured. Also the maximum force that is exerted on the probe has been estimated. This work was supported by the US. D.O.E. contract DE-AC05-00OR22725, and the Oak Ridge Associated Universities ARC program.

  17. The formation mechanism of CO2 and its conversion in the process of coal gasification under arc plasma conditions

    Science.gov (United States)

    He, Xiaojun; Zheng, Mingdong; Qiu, Jieshan; Zhao, Zongbin; Ma, Tengcai

    2006-05-01

    The carbon dioxide (CO2) formation mechanism and co-conversion of CO2 with coal was investigated in the process of coal gasification in a steam medium at atmospheric pressure under arc plasma conditions in a tube-type setup. The arc plasma was diagnosed in situ by optical emission spectroscopy and the gas products were analysed by gas chromatography. CO2 yields are correlated with the quantitative emission peak intensity of the active species in plasma when the operating parameter is changed. The results show that the greater the emission peak intensity of the CH radicals, C2 radicals, OH radicals or O atoms, the smaller the CO2 yield is, which means that the CO2 formation process is inhibited by increasing the concentration of the mentioned active species under arc plasma conditions. On the basis of the diagnosis results, co-conversion of CO2 and coal in a steam medium under plasma conditions was carried out in the same setup and the results show that CO2 conversion reaches 88.6% while the concentration of CO + H2 reaches 87.4%; at the same time, coal conversion is in the range 54.7-68.7%, which proves that co-conversion of CO2 and coal in a steam medium under plasma conditions might be a prospective way to utilize CO2 and the production of synthesis gas.

  18. Simulation of Main Plasma Parameters of a Cylindrical Asymmetric Capacitively Coupled Plasma Micro-Thruster using Computational Fluid Dynamics

    Directory of Open Access Journals (Sweden)

    Amelia eGreig

    2015-01-01

    Full Text Available Computational fluid dynamics (CFD simulations of a radio-frequency (13.56 MHz electro-thermal capacitively coupled plasma (CCP micro-thruster have been performed using the commercial CFD-ACE+ package. Standard operating conditions of a 10 W, 1.5 Torr argon discharge were used to compare with previously obtained experimental results for validation. Results show that the driving force behind plasma production within the thruster is ion-induced secondary electrons ejected from the surface of the discharge tube, accelerated through the sheath to electron temperatures up to 33.5 eV. The secondary electron coefficient was varied to determine the effect on the discharge, with results showing that full breakdown of the discharge did not occur for coefficients coefficients less than or equal to 0.01.

  19. Performance analysis of RDF gasification in a two stage fluidized bed-plasma process.

    Science.gov (United States)

    Materazzi, M; Lettieri, P; Taylor, R; Chapman, C

    2016-01-01

    The major technical problems faced by stand-alone fluidized bed gasifiers (FBG) for waste-to gas applications are intrinsically related to the composition and physical properties of waste materials, such as RDF. The high quantity of ash and volatile material in RDF can provide a decrease in thermal output, create high ash clinkering, and increase emission of tars and CO2, thus affecting the operability for clean syngas generation at industrial scale. By contrast, a two-stage process which separates primary gasification and selective tar and ash conversion would be inherently more forgiving and stable. This can be achieved with the use of a separate plasma converter, which has been successfully used in conjunction with conventional thermal treatment units, for the ability to 'polish' the producer gas by organic contaminants and collect the inorganic fraction in a molten (and inert) state. This research focused on the performance analysis of a two-stage fluid bed gasification-plasma process to transform solid waste into clean syngas. Thermodynamic assessment using the two-stage equilibrium method was carried out to determine optimum conditions for the gasification of RDF and to understand the limitations and influence of the second stage on the process performance (gas heating value, cold gas efficiency, carbon conversion efficiency), along with other parameters. Comparison with a different thermal refining stage, i.e. thermal cracking (via partial oxidation) was also performed. The analysis is supported by experimental data from a pilot plant.

  20. A Multiresolution Method for Parameter Estimation of Diffusion Processes.

    Science.gov (United States)

    Kou, S C; Olding, Benjamin P; Lysy, Martin; Liu, Jun S

    2012-12-01

    Diffusion process models are widely used in science, engineering and finance. Most diffusion processes are described by stochastic differential equations in continuous time. In practice, however, data is typically only observed at discrete time points. Except for a few very special cases, no analytic form exists for the likelihood of such discretely observed data. For this reason, parametric inference is often achieved by using discrete-time approximations, with accuracy controlled through the introduction of missing data. We present a new multiresolution Bayesian framework to address the inference difficulty. The methodology relies on the use of multiple approximations and extrapolation, and is significantly faster and more accurate than known strategies based on Gibbs sampling. We apply the multiresolution approach to three data-driven inference problems - one in biophysics and two in finance - one of which features a multivariate diffusion model with an entirely unobserved component.

  1. Titanium Metal Powder Production by the Plasma Quench Process

    Energy Technology Data Exchange (ETDEWEB)

    R. A. Cordes; A. Donaldson

    2000-09-01

    The goals of this project included the scale-up of the titanium hydride production process to a production rate of 50 kg/hr at a purity level of 99+%. This goal was to be achieved by incrementally increasing the production capability of a series of reactor systems. This methodic approach was designed to allow Idaho Titanium Technologies to systematically address the engineering issues associated with plasma system performance, and powder collection system design and performance. With quality powder available, actual fabrication with the titanium hydride was to be pursued. Finally, with a successful titanium production system in place, the production of titanium aluminide was to be pursued by the simultaneously injection of titanium and aluminum precursors into the reactor system. Some significant accomplishments of the project are: A unique and revolutionary torch/reactor capable of withstanding temperatures up to 5000 C with high thermal efficiency has been operated. The dissociation of titanium tetrachloride into titanium powder and HC1 has been demonstrated, and a one-megawatt reactor potentially capable of producing 100 pounds per hour has been built, but not yet operated at the powder level. The removal of residual subchlorides and adsorbed HC1 and the sintering of powder to form solid bodies have been demonstrated. The production system has been operated at production rates up to 40 pounds per hour. Subsequent to the end of the project, Idaho Titanium Technologies demonstrated that titanium hydride powder can indeed be sintered into solid titanium metal at 1500 C without sintering aids.

  2. The effects of forming parameters on conical ring rolling process.

    Science.gov (United States)

    Meng, Wen; Zhao, Guoqun; Guan, Yanjin

    2014-01-01

    The plastic penetration condition and biting-in condition of a radial conical ring rolling process with a closed die structure on the top and bottom of driven roll, simplified as RCRRCDS, were established. The reasonable value range of mandrel feed rate in rolling process was deduced. A coupled thermomechanical 3D FE model of RCRRCDS process was established. The changing laws of equivalent plastic strain (PEEQ) and temperature distributions with rolling time were investigated. The effects of ring's outer radius growth rate and rolls sizes on the uniformities of PEEQ and temperature distributions, average rolling force, and average rolling moment were studied. The results indicate that the PEEQ at the inner layer and outer layer of rolled ring are larger than that at the middle layer of ring; the temperatures at the "obtuse angle zone" of ring's cross-section are higher than those at "acute angle zone"; the temperature at the central part of ring is higher than that at the middle part of ring's outer surfaces. As the ring's outer radius growth rate increases at its reasonable value ranges, the uniformities of PEEQ and temperature distributions increase. Finally, the optimal values of the ring's outer radius growth rate and rolls sizes were obtained.

  3. The Effects of Forming Parameters on Conical Ring Rolling Process

    Directory of Open Access Journals (Sweden)

    Wen Meng

    2014-01-01

    Full Text Available The plastic penetration condition and biting-in condition of a radial conical ring rolling process with a closed die structure on the top and bottom of driven roll, simplified as RCRRCDS, were established. The reasonable value range of mandrel feed rate in rolling process was deduced. A coupled thermomechanical 3D FE model of RCRRCDS process was established. The changing laws of equivalent plastic strain (PEEQ and temperature distributions with rolling time were investigated. The effects of ring’s outer radius growth rate and rolls sizes on the uniformities of PEEQ and temperature distributions, average rolling force, and average rolling moment were studied. The results indicate that the PEEQ at the inner layer and outer layer of rolled ring are larger than that at the middle layer of ring; the temperatures at the “obtuse angle zone” of ring’s cross-section are higher than those at “acute angle zone”; the temperature at the central part of ring is higher than that at the middle part of ring’s outer surfaces. As the ring’s outer radius growth rate increases at its reasonable value ranges, the uniformities of PEEQ and temperature distributions increase. Finally, the optimal values of the ring’s outer radius growth rate and rolls sizes were obtained.

  4. The Main Plasma Chemical Process of Nitric Oxide Production by Arc Discharge%The Main Plasma Chemical Process of Nitric Oxide Production by Arc Discharge

    Institute of Scientific and Technical Information of China (English)

    杨旗; 胡辉; 陈卫鹏; 许杰; 张锦丽; 吴双

    2011-01-01

    By adopting the optical multi-channel analyzer combined with fourier transform infrared (FTIR) spectrometer, the dominant free radicals and products generated by arc discharge were measured and studied, and the main plasma chemical reaction process in the nitric oxide production by arc discharge was identified. Plasma chemical kinetic curves of O, O2, N2, N and NO were simulated by using CHEMKIN and MATLAB. The results show that the main plasma chemical reaction process of nitric oxide production by arc discharge is a replacement reaction between O and N2, where NO can be generated instantaneously when discharging reaches stable.

  5. The Influence of the RF PACVD MS Process Parameters on the Physicochemical Properties of Hydroxyapatite Coatings

    Directory of Open Access Journals (Sweden)

    Niedzielska A.

    2015-12-01

    Full Text Available Hydroksyapatite (HAp as the coating, is produced using different methods of deposition, among others: laser ablation method, sol-gel, electrophoresis, thermal sputtering or magnetron spraying with the usage of high frequency. Attempts to benefit from such a wide spectrum of existing methods are related to the fact that this material possesses many advantages. We have to distinguish, among others, proper biological properties, i.e. both - high bio-tolerance and high osteo-inductivity [1,2]. However, it is worth mentioning that the material also presents disadvantages, i.e. it indicates too quick resorption within the biological environment, depending on its obtained form. In case when HAp is in the amorphous form, it undergoes a very rapid process of dissolving in the tissue environment. [3] In order to prevent the above, it is important to produce the coatings with a regulative level of cristallinity. In the presented research the hydroxyapatite coating produced using RF PACVD MS plasma method (Radio Frequency Plasma Assisted Chemical Vapor Deposition Magnetron Sputtering possesses the above mentioned amorphous form. Nevertheless, due to the usage of ‘bubbler’, allowing for delivery of hydroxyl groups into the operating chamber, it was possible to receive the Hap coatings in a crystalline form. Changing the operating pressure (the amount of bonds - OH, during sputtering, it was checked what is the influence of that parameter on the physicochemical properties of obtained coatings. Scanning electron microscopy (SEM was used for the founding research as well as the Roentgen Apparatus Analyser (EDS. The Phase composition of a created coating was researched using the Roentgen diffract-meter (XRD. The measures of thickness were conducted using contact-profilometry. Nano-indentation technique was used to assess the mechanical properties. Obtained results of research encourage for further researches related to the influence of hydroxyl groups on the

  6. Investigation of the atomic emission spectroscopy of F atoms and CF2 molecules in CF4 plasma processing

    Science.gov (United States)

    Jin, Huiliang; Li, Jie; Tang, Caixue; Deng, Wenhui; Chen, Xianhua

    2016-10-01

    The surface chemistry reaction involved in the processing of Atmospheric Pressure Plasma Jet (APPJ) produced from CF4 precursor has been explored. The atomic emission spectroscopy of F atoms and CF2 molecules was investigated as they contribute to substrate etching and FC film formation during APPJ processing. Optical emission spectroscopy (OES) spectra were acquired for CF4 plasma, relative concentrations of excited state species of F atoms and CF2 molecules were also dependent upon plasma parameters. The densities of F atoms increased dramatically with increasing applied RF power, whereas CF2 molecules decreased monotonically over the same power range, the subsequent electron impacted decomposition of plasma species after CF4 precursor fragmentation. The spectrum of the F atoms and CF2 molecules fallowed the same tendency with the increasing concentration of gas CF4, reaching the maximum at the 20sccm and 15sccm respectively, and then the emission intensity of reactive atoms decreased with more CF4 molecules participating. Addition certain amount O2 into CF4 plasma resulted in promoting CF4 dissociation, O2 can easily react with the dissociation product of CF2 molecules, which inhibit the compound of the F atoms, so with the increasing concentration of O2, the concentration of the CF2 molecules decreased and the emission intensities of F atoms showed the maximum at the O2/CF4 ratio of 20%. These results have led to the development of a scheme that illustrates the mechanisms of surface chemistry reaction and the affection of plasma parameters in CF4 plasma systems with respect to F and CF2 gas-phase species.

  7. Parameter Sensitivity of the Microdroplet Vacuum Freezing Process

    Directory of Open Access Journals (Sweden)

    Zhijun Zhang

    2015-01-01

    Full Text Available The vacuum freezing process of microdroplets (1 mm. Pressure and droplet diameter have an effect on cooling and freezing stages, but initial temperature only affects the cooling stage. The thermal conductivity coefficient kl affected the cooling stage, whereas ki affected the freezing stage. Heat capacity Cl affected the cooling stage, but Ci has virtually no effect on all stages. The actual latent heat of freezing ΔH was also affected. Higher density corresponds to lower cooling rate in the cooling stage.

  8. Instrument maintenance of ultrasonic influences parameters measurement in technological processes

    Directory of Open Access Journals (Sweden)

    Tomal V. S.

    2008-04-01

    Full Text Available The contact and non-contact vibration meters for intermittent and continuous control of the vibration amplitude in the ultrasonic technological equipment have been developed. And in order to estimate the cavitation intensity in liquids the authors have developed cavitation activity indicators and cavitation sensitivity meters, allowing to measure the magnitude of the signal level in the range of maximum spectral density of cavitation noise. The developed instruments allow to improve the quality of products, reduce the defect rate and power consumption of equipment by maintaining optimum conditions of the process.

  9. Nicotine, cotinine, and trans-3-hydroxycotinine levels in seminal plasma of smokers: effects on sperm parameters.

    Science.gov (United States)

    Pacifici, R; Altieri, I; Gandini, L; Lenzi, A; Pichini, S; Rosa, M; Zuccaro, P; Dondero, F

    1993-10-01

    Sperm samples from 44 cigarette smokers and 50 nonsmokers attending an infertility clinic were examined by high-performance liquid chromatography (HPLC) assay and HPLC-mass spectrometry for the presence of nicotine (NIC), cotinine (COT), and trans-3'-hydroxycotinine (THOC) in seminal plasma. Smokers were found to have levels of COT and THOC in seminal plasma that were similar to those found in serum. The level of NIC was significantly increased in seminal plasma compared to serum. Total motility of spermatozoa was significantly and negatively correlated to COT and THOC levels in seminal plasma. Forward motility of spermatozoa was correlated only with cotinine semen levels. On the basis of these results, we suggest that the presence of tobacco smoke constituents in seminal plasma could provide a warning of the adverse effects of cigarette smoke on the physiology of reproduction.

  10. Experimental approach for thermal parameters estimation during glass forming process

    Science.gov (United States)

    Abdulhay, B.; Bourouga, B.; Alzetto, F.; Challita, C.

    2016-10-01

    In this paper, an experimental device designed and developedto estimate thermal conditions at the Glass / piston contact interface is presented. This deviceis made of two parts: the upper part contains the piston made of metal and a heating device to raise the temperature of the piston up to 500 °C. The lower part is composed of a lead crucible and a glass sample. The assembly is provided with a heating system, an induction furnace of 6 kW for heating the glass up to 950 °C.The developed experimental procedure has permitted in a previous published study to estimate the Thermal Contact ResistanceTCR using the inverse technique developed by Beck [1]. The semi-transparent character of the glass has been taken into account by an additional radiative heat flux and an equivalent thermal conductivity. After the set-up tests, reproducibility experiments for a specific contact pressure have been carried outwith a maximum dispersion that doesn't exceed 6%. Then, experiments under different conditions for a specific glass forming process regarding the application (Packaging, Buildings and Automobile) were carried out. The objective is to determine, experimentallyfor each application,the typical conditions capable to minimize the glass temperature loss during the glass forming process.

  11. A Stochastic Process Approach of the Drake Equation Parameters

    CERN Document Server

    Glade, Nicolas; Bastien, Olivier

    2011-01-01

    The number N of detectable (i.e. communicating) extraterrestrial civilizations in the Milky Way galaxy is usually done by using the Drake equation. This equation was established in 1961 by Frank Drake and was the first step to quantifying the SETI field. Practically, this equation is rather a simple algebraic expression and its simplistic nature leaves it open to frequent re-expression An additional problem of the Drake equation is the time-independence of its terms, which for example excludes the effects of the physico-chemical history of the galaxy. Recently, it has been demonstrated that the main shortcoming of the Drake equation is its lack of temporal structure, i.e., it fails to take into account various evolutionary processes. In particular, the Drake equation doesn't provides any error estimation about the measured quantity. Here, we propose a first treatment of these evolutionary aspects by constructing a simple stochastic process which will be able to provide both a temporal structure to the Drake e...

  12. Target rotation parameter estimation for ISAR imaging via frame processing

    Institute of Scientific and Technical Information of China (English)

    Xuezhi Wang; Yajing Huang; Weiping Yang; Bill Moran

    2016-01-01

    Frame processing method offers a model-based approach to Inverse Synthetic Aperture Radar (ISAR) imaging. It also provides a way to estimate the rotation rate of a non-cooperative target from radar returns via the frame operator properties. In this paper, the relationship between the best achievable ISAR image and the reconstructed image from radar returns was derived in the framework of Finite Frame Processing theory. We show that image defocusing caused by the use of an incorrect target rotation rate is interpreted under the FP method as a frame operator mismatch problem which causes energy dispersion. The unknown target rotation rate may be computed by optimizing the frame operator via a prominent point. Consequently, a prominent intensity maximization method in FP framework was proposed to estimate the underlying target rotation rate from radar returns. In addition, an image filtering technique was implemented to assist searching for a prominent point in practice. The proposed method is justified via a simulation analysis on the performance of FP imaging versus target rotation rate error. Effectiveness of the proposed method is also confirmed from real ISAR data experiments.

  13. Parameter Optimization of Nitriding Process Using Chemical Kinetics

    Science.gov (United States)

    Özdemir, İ. Bedii; Akar, Firat; Lippmann, Nils

    2016-09-01

    Using the dynamics of chemical kinetics, an investigation to search for an optimum condition for a gas nitriding process is performed over the solution space spanned by the initial temperature and gas composition of the furnace. For a two-component furnace atmosphere, the results are presented in temporal variations of gas concentrations and the nitrogen coverage on the surface. It seems that the exploitation of the nitriding kinetics can provide important feedback for setting the model-based control algorithms. The present work shows that when the nitrogen gas concentration is not allowed to exceed 6 pct, the Nad coverage can attain maximum values as high as 0.97. The time evolution of the Nad coverage also reveals that, as long as the temperature is above the value where nitrogen poisoning of the surface due to the low-temperature adsorption of excess nitrogen occurs, the initial ammonia content in the furnace atmosphere is much more important in the nitriding process than is the initial temperature.

  14. Process Parameter Optimization of the Pulsed Current Argon Tungsten Arc Welding of Titanium Alloy

    Institute of Scientific and Technical Information of China (English)

    M.Balasubramanian; V.Jayabalan; V.Balasubramanian

    2008-01-01

    The selection of process parameters for obtaining optimal tensile properties in the pulsed current gas tungsten arc welding is presented. The tensile properties include ultimate tensile strength, yield strength and notch tensile strength. All these characteristics are considered together in the selection of process parameters by modified taguchi method to analyse the effect of each welding process parameter on tensile properties. Experimental results are furnished to illustrate the approach.

  15. Modelling and optimization of film thickness variation for plasma enhanced chemical vapour deposition processes

    Science.gov (United States)

    Waddell, Ewan; Gibson, Des; Lin, Li; Fu, Xiuhua

    2011-09-01

    This paper describes a method for modelling film thickness variation across the deposition area within plasma enhanced chemical vapour deposition (PECVD) processes. The model enables identification and optimization of film thickness uniformity sensitivities to electrode configuration, temperature, deposition system design and gas flow distribution. PECVD deposition utilizes a co-planar 300mm diameter electrodes with separate RF power matching to each electrode. The system has capability to adjust electrode separation and electrode temperature as parameters to optimize uniformity. Vacuum is achieved using dry pumping with real time control of butterfly valve position for active pressure control. Comparison between theory and experiment is provided for PECVD of diamond-like-carbon (DLC) deposition onto flat and curved substrate geometries. The process utilizes butane reactive feedstock with an argon carrier gas. Radiofrequency plasma is used. Deposited film thickness sensitivities to electrode geometry, plasma power density, pressure and gas flow distribution are demonstrated. Use of modelling to optimise film thickness uniformity is demonstrated. Results show DLC uniformity of 0.30% over a 200 mm flat zone diameter within overall electrode diameter of 300mm. Thickness uniformity of 0.75% is demonstrated over a 200mm diameter for a non-conformal substrate geometry. Use of the modelling method for PECVD using metal-organic chemical vapour deposition (MOCVD) feedstock is demonstrated, specifically for deposition of silica films using metal-organic tetraethoxy-silane. Excellent agreement between experimental and theory is demonstrated for conformal and non-conformal geometries. The model is used to explore scalability of PECVD processes and trade-off against film thickness uniformity. Application to MEMS, optical coatings and thin film photovoltaics is discussed.

  16. The kinetic studies of direct methane oxidation to methanol in the plasma process

    Institute of Scientific and Technical Information of China (English)

    INDARTO Antonius; CHOI Jae-Wook; LEE Hwaung; SONG Hyung Keun

    2008-01-01

    The research outlined here includes a study of methanol production from direct methane conversion by means of thermal and plasma method. The kinetic study, derived from thermal-based approach, was carried out to investigate thoroughly the possible intermediate species likely to be presented in the process. A set of plasma experiments was undertaken by using dielectric barrier discharge (DBD), classified as non-thermal plasma, done at atmospheric pressure and room temperature. Plasma proc-ess yields more methanol than thermal process at the same methane conversion rates and methane to oxygen feed ratios. Oxidation reaction of thermal process resulted CO and CO2 as the most dominant products and the selectivity reached 19% and 68%, respectively. Moreover, more CO and less CO2 were produced in plasma process than in thermal process. The selectivity of CO and CO2 by plasma was 47% and 20%, respectively. Ethane (C2H6) was detected as the only higher hydrocarbon with a signifi-cant concentration. The concentration of ethane reached 9% of the total products in plasma process and 17% in thermal process. The maximum selectivity of methanol, the target material of this research, was 12% obtained by plasma method and less than 5% by thermal process. In some certain points, the kinetic model closely matched with the experimental results.

  17. Effect of applying static electric field on the physical parameters and dynamics of laser-induced plasma

    Directory of Open Access Journals (Sweden)

    Asmaa Elhassan

    2010-04-01

    Full Text Available In order to improve the performance of the LIBS technique – in particular its sensitivity, reproducibility and limit of detection – we studied the effect of applying a static electric field with different polarities on the emission spectra obtained in a typical LIBS set-up. The physical parameters of the laser-induced plasma, namely the electron density Ne and the plasma temperature Te, were studied under such circumstances. In addition to the spectroscopic analysis of the plasma plume emission, the laser-induced shock waves were exploited to monitor the probable changes in the plasma plume dynamics due to the application of the electric field. The study showed a pronounced enhancement in the signal-to-noise (S/N ratio of different Al, neutral and ionic lines under forward biasing voltage (negative target and positive electrode. On the other hand, a clear deterioration of the emission line intensities was observed under conditions of reversed polarity. This negative effect may be attributed to the reduction in electron-ion recombinations due to the stretched plasma plume. The plasma temperature showed a constant value in the average with the increasing electric field in both directions. This effect may be due to the fact that the measured values of Te were averaged over the whole plasma emission volume. The electron density was observed to decrease slightly in the case of forward biasing while no significant effect was noticed in the case of reversed biasing. This slight decrease in Ne can be interpreted in view of the increase in the rate of electron–ion recombinations due to the presence of the electric field. No appreciable effects of the applied electric field on the plasma dynamics were noticed.

  18. Applications and challenges of plasma processes in nanobiotechnology

    Energy Technology Data Exchange (ETDEWEB)

    Rossi, F; Colpo, P, E-mail: francois.rossi@jrc.ec.europa.eu [European Commission, Joint Research Centre, Institute for Health and Consumer Protection (IHCP), I-21020, Ispra (Italy)

    2011-05-04

    We present an overview of the possibilities offered by plasma technologies, in particular the combination plasma polymers deposition, colloidal lithography, e-beam lithography and microcontact printing, to produce micro- and nanostructured surfaces with chemical and topographical contrast for applications in nanobiotechnology. It is shown that chemical and topographical patterns can be obtained on different substrates, with dimensions down to a few tenths of 10 nm. The applications of these nanostructured surfaces in biology, biochemistry and biodetection are presented and the advantages and limitation of the plasma techniques in this context underlined.

  19. Influence of Process Parameters on Coal Combustion Performance

    DEFF Research Database (Denmark)

    Lans, Robert Pieter Van Der

    The objective of this study is to improve the understanding of nitrogen oxide formation and carbon burnout during the combustion of pulverized coal, and to contribute to addressing the potential of chemical engineering models for the prediction of furnace temperatures, NO emissions and the amount...... study has been performed in order to initiate an investigation of the potential of chemical engineering models to predict NO from pulverized fuel burners. The success of chemical engineering modeling is strongly connected to the simplification of the flow pattern into a reactor configuration...... and swirl number on the flow pattern in the near burner zone of the laboratory furnace-model were studied. Experimentally obtained residence time distributions have been used to derive a chemical reaction engineering model for the mixing process. The model is based on a combination of plug flow reactors...

  20. Influence of Process Parameters on Coal Combustion Performance

    DEFF Research Database (Denmark)

    Lans, Robert Pieter Van Der

    The objective of this study is to improve the understanding of nitrogen oxide formation and carbon burnout during the combustion of pulverized coal, and to contribute to addressing the potential of chemical engineering models for the prediction of furnace temperatures, NO emissions and the amount...... of carbon in ash. To this purpose, the effect of coal quality on NO and burnout has been investigated experimentally, a radiation heat balance has been developed based on simple chemical engineering methodology, and a mixing study has been conducted in order to describe the near burner macro mixing in terms...... with self-sustaining flames, while extensions are made to full scale boilers and furnace modeling. Since coal combustion and flame aerodynamics are reviewed elsewhere, these phenomena are only treated briefly. The influence of coal type and process conditions on NO formation and carbon burnout has been...

  1. Parameters influencing polymer particle layering of the dry coating process.

    Science.gov (United States)

    Kablitz, Caroline Désirée; Kappl, Michael; Urbanetz, Nora Anne

    2008-06-01

    The dry coating process is an emerging coating technology using neither organic solvents nor water. In contrast to liquid-borne coatings, coating material application and film formation are divided into two phases, the coating phase where the powdery coating material is applied together with the liquid plasticizer, and the curing phase. In this study the coating phase was characterized with respect to the forces acting between the polymer particles during material application. Atomic force microscopy was conducted measuring the interparticle forces which were related to the coating efficiency. The influence of different liquid additives on the interparticle forces and the coating efficiency were evaluated. HPMCAS was used as enteric resistant polymer, triethylcitrate (TEC), Myvacet (diacetylated monoglyceride) and a mixture of both as liquid additives. Interparticle forces were found to be similar when using TEC or a mixture of TEC and Myvacet. In contrast, interparticle forces were higher when using solely Myvacet. This is attributed to the fact that Myvacet does not penetrate into the polymer without TEC which is acting as a penetration enhancer. As Myvacet remains predominantly on the particle surface, capillary forces act between the particles explaining high interparticle forces. The highest interparticle force determined by AFM is in accordance to the highest coating efficiency which has been found for the corresponding coating formulation containing HPMCAS and Myvacet. Consequently, it is demonstrated that the ability of the liquid to remain on the surface of the polymer and to build up capillary forces is crucial for the material application.

  2. Impacts of Ambient and Ablation Plasmas on Short- and Ultrashort-Pulse Laser Processing of Surfaces

    Directory of Open Access Journals (Sweden)

    Nadezhda M. Bulgakova

    2014-12-01

    Full Text Available In spite of the fact that more than five decades have passed since the invention of laser, some topics of laser-matter interaction still remain incompletely studied. One of such topics is plasma impact on the overall phenomenon of the interaction and its particular features, including influence of the laser-excited plasma re-radiation, back flux of energetic plasma species, and massive material redeposition, on the surface quality and processing efficiency. In this paper, we analyze different plasma aspects, which go beyond a simple consideration of the well-known effect of plasma shielding of laser radiation. The following effects are considered: ambient gas ionization above the target on material processing with formation of a “plasma pipe”; back heating of the target by both laser-driven ambient and ablation plasmas through conductive and radiative heat transfer; plasma chemical effects on surface processing including microstructure growth on liquid metals; complicated dynamics of the ablation plasma flow interacting with an ambient gas that can result in substantial redeposition of material around the ablation spot. Together with a review summarizing our main to-date achievements and outlining research directions, we present new results underlining importance of laser plasma dynamics and photoionization of the gas environment upon laser processing of materials.

  3. Dynamic Control of Microwave Plasma Sources for Material Processing by Using Hyper-Simulation

    Science.gov (United States)

    Yasaka, Yasuyoshi; Tsuji, Akihiro

    2010-11-01

    Uniformity of etching or deposition over a wafer is one of the key features for plasma processing with large-size wafers. The uniformity can be measured as a result of a process, and correction or improvement of the uniformity is made by changing device parameters such as power levels, gas flow rates, timings, and so on. Evaluation and control are, however, not combined or unified as a problem of plasma physics. They are assigned as the input and output of a black box of empirical transfer function obtained by expert systems or neural networks. We are going to establish a novel control system based on physics, in which a fluid simulation is used to obtain a power deposition profile necessary to produce the two-dimensional density distribution of desire. A control system of a microwave slot antenna then changes power distribution dynamically according to the output of the simulation. It should be noted that this simulation has inputs and outputs opposite to conventional ones, which, we call hyper-simulation, is one of the novel features of the control system.

  4. Hybrid processing of Ti-6Al-4V using plasma immersion ion implantation combined with plasma nitriding

    Directory of Open Access Journals (Sweden)

    Silva Maria Margareth da

    2006-01-01

    Full Text Available Based on the fact that the Ti-6Al-4V alloy has good mechanical properties, excellent resistance to corrosion and also excellent biocompatibility, however with low wear resistance, this work aims to test plasma processes or combination of plasma and ion implantation processes to improve these characteristics. Two types of processing were used: two steps PIII (Plasma Immersion Ion Implantation combined with PN (Plasma Nitriding and single step PIII treatment. According to Auger Electron Spectroscopy (AES results, the best solution was obtained by PIII for 150 minutes resulting in ~ 65 nm of nitrogen implanted layer, while the sample treated with PIII (75 minutes and PN (75 minutes reached ~ 35 nm implanted layer. The improvement of surface properties could also be confirmed by the nanoindentation technique, with values of hardness increasing for both processes. AFM (Atomic Force Microscopy characterization showed that the single step PIII process presented greater efficiency than the duplex process (PIII + PN, probably due to the sputtering occurring during the second step (PN removing partially the implanted layer of first step (PIII.

  5. Effect of magnetic configuration on plasma parameters in the H-1 heliac

    Energy Technology Data Exchange (ETDEWEB)

    Blackwell, B.D.; Pretty, D.G.; Harris, J.H.; Howard, J.; Shats, M.G.; Collis, S.M.; Gardner, H.J.; Michael, C.A.; Punzmann, H. [Plasma Research Laboratory, Research School of Physical Sciences and Engineering Australian National University, ACT (Australia)

    2003-07-01

    The H-1 heliac is a current-free stellarator with a helical magnetic axis which twists around the machine axis (a circular ring conductor, radius 1m) three times in one toroidal rotation. It us a ''flexible'' heliac composed almost entirely of circular coils with the exception of the helical control winding, which also wraps around the ring conductor, in phase with the magnetic axis of the plasma, but with a smaller swing radius (95 mm c.f. {proportional_to} 230 mm). In addition to indicating particle confinement times, this phenomenon may be sensitive to plasma generation efficiency. There may be some interaction between configuration and impurity generation, as plasma boundaries and strike points are varied. Various plasma conditions and formation techniques are compared. (orig.)

  6. Influence of instrumental parameters on the kinetic energy of ions and plasma temperature for a hexapole collision/reaction-cell-based inductively coupled plasma quadrupole mass spectrometer.

    Science.gov (United States)

    Favre, Georges; Brennetot, René; Chartier, Frédéric; Tortajada, Jeanine

    2009-02-01

    Inductively coupled plasma mass spectrometry (ICP-MS) is widely used in inorganic analytical chemistry for element and/or isotope ratio measurements. The presence of interferences, which is one of the main limitations of this method, has been addressed in recent years with the introduction of collision/reaction cell devices on ICP-MS apparatus. The study of ion-molecule reactions in the gas phase then became of great importance for the development of new analytical strategies. Knowing the kinetic energy and the electronic states of the ions prior to their entrance into the cell, i.e., just before they react, thereby constitutes crucial information for the interpretation of the observed reactivities. Such studies on an ICP-MS commonly used for routine analyses require the determination of the influence of different instrumental parameters on the energy of the ions and on the plasma temperature from where ions are sampled. The kinetic energy of ions prior to their entrance into the cell has been connected to the voltage applied to the hexapole according to a linear relationship determined from measurements of ion energy losses due to collisions with neutral gas molecules. The effects of the plasma forward power, sampling depth, and the addition of a torch shield to the ICP source were then examined. A decrease of the plasma potential due to the torch shielding, already mentioned in the literature, has been quantified in this study at about 3 V.

  7. Microstructure and mechanical properties of nickel-chrome-bor-silicon layers produced by the atmospheric plasma spray process

    Directory of Open Access Journals (Sweden)

    Mihailo R. Mrdak

    2012-01-01

    Full Text Available This paper analyzes the influence of plasma spray parameters on the microstructure and mechanical properties of NiCrBSi coatings deposited by the atmospheric plasma spray (APS process. The microstructure and mechanical properties of plasma spray coatings are determined by the interaction of plasma ions with powder particles when the rate and temperature of plasma particles are transferred to powder particles. The interaction effect directly depends on the time the powder particles spend in plasma, and that time is defined by the deposition distance for each type of powder, depending on the grain size, melting temperature and specific mass. In order to obtain homogeneous and dense coatings, three distances (70,120 and 170 mm from the substrate were used in the research. The coating of the best structural and mechanical characteristics was remelted and fused to the base in order to obtain a better structure. Self - fluxing NiCrBSi alloys are widely used because of the good resistance of boride, carbide and silicide solid phases to wear and corrosion. The morphology of powder particles was examined in the SEM (Scanning Electron Microscope, while the microstructure of the layers was assessed using a light microscope. The microstructural analysis of the deposited layers was performed in accordance with the Pratt-Whitney standard. The mechanical properties of the layers were assessed by applying the HV0.3 method for microhardness testing and tensile testing was applied to test bond strength.

  8. Relationship between Microcellular Foaming Injection Molding Process Parameters and Cell Size

    Institute of Scientific and Technical Information of China (English)

    HU Guang-hong; JIANG Chao-dong; CUI Zhen-shan

    2008-01-01

    In order to study the relationship between the main process parameters and the cell size, the mathematical model of cell growth of microcellular foaming injection process is built. Then numeric simulation is employed as experimental method, and the Taguchi method is used to analyze significance of effect of process parameters on the cell size. At last the process parameters are focused on melt temperature, injection time, mold temperature and pre- filled volume. The significance order from big to small of the effect of each process parameters on cell size is melt temperature, pre-filled volume, injection time, and mold temperature. On the basis of above research, the effect of each process parameter on cell size is further researched.Appropriate reduction of the melt temperature and increase of the we-filled volume can optimize the cell size effectively, while the effects of injection time and mold temperature on cell size are less significant.

  9. An improved model to analyze Langmuir probe assisted photo-detachment signal for measuring electronegative plasma parameters

    Science.gov (United States)

    Sirse, Nishant; Oudini, Noureddine; Bendib, Abderrezeg; Ellingboe, Albert R.

    2016-09-01

    A diagnostic technique for measuring negative ion parameters based on Langmuir probe assisted laser photo-detachment relies on a theoretical model which relates the rise in the electron saturation current to electronegativity in the plasma. The existing model depend on various assumptions and neglect electrostatic potential barrier formed between the laser column (electropositive column) and the surrounding electronegative plasma in order to prevent the outward flow of electrons from the electropositive plasma column. These assumptions leads to erroneous estimation of the plasma electronegativity. In the present work, we present an analytical model to analyze Langmuir probe assisted photo-detachment signal in order to improve the accuracy of measured electronegativity and extended this technique for measuring electron temperature and charged species density. The analytical model is validated using both experiments and particle-in-cell simulation. The results shows improved accuracy in the measured parameters when compared to existing model. This work was supported by the Korea Institute for the Advancement of Technology and Ministry of Knowledge Economy (L-2010-1438-000), Republic of Korea, Enterprise Ireland and the European Regional Development Fund (ERDF) under NSRF 2007-2013.

  10. Evaluation of the operational parameters for NBI-driven fusion in low-gain tokamaks with two-component plasma

    Science.gov (United States)

    Chirkov, A. Yu.

    2015-09-01

    Low gain (Q ~ 1) fusion plasma systems are of interest for concepts of fusion-fission hybrid reactors. Operational regimes of large modern tokamaks are close to Q  ≈  1. Therefore, they can be considered as prototypes of neutron sources for fusion-fission hybrids. Powerful neutral beam injection (NBI) can support the essential population of fast particles compared with the Maxwellial population. In such two-component plasma, fusion reaction rate is higher than for Maxwellian plasma. Increased reaction rate allows the development of relatively small-size and relatively inexpensive neutron sources. Possible operating regimes of the NBI-heated tokamak neutron source are discussed. In a relatively compact device, the predictions of physics of two-component fusion plasma have some volatility that causes taking into account variations of the operational parameters. Consequent parameter ranges are studied. The feasibility of regimes with Q  ≈  1 is shown for the relatively small and low-power system. The effect of NBI fraction in total heating power is analyzed.

  11. Real time measurement of plasma macroscopic parameters on RFX-mod using a limited set of sensors

    Science.gov (United States)

    Kudlacek, Ondrej; Zanca, Paolo; Finotti, Claudio; Marchiori, Giuseppe; Cavazzana, Roberto; Marrelli, Lionello

    2015-10-01

    A method to estimate the plasma boundary and global parameters such as βp+li/2 and the edge safety factor q95 is described. The method is based on poloidal flux extrapolation in the vacuum region between the plasma and the magnetic measurements, and it is efficient and accurate even if a limited set of sensors is used. The discrepancy between the plasma boundary provided by this method and the boundary computed by the Grad-Shafranov solver MAXFEA is lower than 8 mm in all the considered cases. Moreover, the method is robust against the noise level present in the RFX-mod measurements. The difference between the estimated global parameters and the MAXFEA simulation results is lower than 4%. The method was finally implemented in the RFX-mod shape control system, working at 5 kHz cycle frequency, to provide a reliable set of plasma-wall distances (gaps) used as feedback signals. Experimental results obtained in one year of RFX-mod operation are shown.

  12. Optimization of the tape placement process parameters for carbon–PPS composites

    NARCIS (Netherlands)

    Grouve, W.J.B.; Warnet, L.; Rietman, B.; Visser, H.A.; Akkerman, R.

    2013-01-01

    The interrelation between process parameters, material properties and interlaminar bond strength is investigated for the laser assisted tape placement process. Unidirectionally carbon reinforced poly(phenylene sulfide) (PPS) tapes were welded onto carbon woven fabric reinforced PPS laminates. The la

  13. Kinetic parameters and intraindividual fluctuations of ochratoxin A plasma levels in humans

    Energy Technology Data Exchange (ETDEWEB)

    Studer-Rohr, I. [Inst. of Toxicology, Swiss Federal Inst. of Tech. and Univ. of Zurich, Schwerzenbach (Switzerland); Dept. of Food Science, Swiss Federal Inst. of Tech., Zurich (Switzerland); Schlatter, J. [Toxicology Section, Div. of Food Science, Swiss Federal Office of Public Health, Zurich (Switzerland); Dietrich, D.R. [Dept. of Environmental Toxicology, Univ. of Konstanz, Konstanz (Germany); Inst. of Toxicology, Swiss Federal Inst. of Tech. and Univ. of Zurich, Schwerzenbach (Switzerland)

    2000-11-01

    The mycotoxin ochratoxin A (OTA) is a rodent carcinogen produced by species of the ubiquitous fungal genera Aspergillus and Penicillium. OTA is found in a variety of food items and as a consequence is also found in human plasma (average concentrations found in this study: 0.1-1 ng OTA/ml plasma). To improve the scientific basis for cancer risk assessment the toxicokinetic profile of OTA was studied in one human volunteer following ingestion of 395 ng {sup 3}H-labeled OTA (3.8 {mu}Ci). A two-compartment open model consisting of a central compartment was found to best describe the in vivo data. This two-compartment model consisted of a fast elimination and distribution phase (T{sub 1/2} about 20 h) followed by a slow elimination phase (renal clearance about 0.11 ml/min.) and a calculated plasma half-life of 35.55 days. This half-life was approximately eight times longer than that determined previously in rats. In addition, the intraindividual fluctuation of OTA plasma levels was investigated in eight individuals over a period of 2 months. The concentrations determined ranged between 0.2 and 0.9 ng OTA/ml plasma. The plasma levels in some individuals remained nearly constant over time, while others varied considerably (e.g. increase of 0.4 ng/ml within 3 days, decrease of 0.3 ng/ml within 5 days) during the observation period. This intraindividual fluctuation in OTA plasma levels, which may represent differences in OTA exposure and/or metabolism, as well as the large difference in plasma half-life in humans compared to rats must be taken into consideration when the results of rat cancer study data are extrapolated to humans for risk assessment purposes. (orig.)

  14. STUDY ON THE PRESSURE IN PLASMA ARC

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The axial pressure in plasma arc is measured under different conditions. The effects of the parameters, such as welding current, plasma gas flow rate, electrode setback and arc length, on the pressure in plasma arc are investigated and quantitative analyzed to explain the relationship between the quality of weld and the matching of parameters in plasma arc welding process.

  15. Atmospheric-Pressure Plasma Interaction with Soft Materials as Fundamental Processes in Plasma Medicine.

    Science.gov (United States)

    Takenaka, Kosuke; Miyazaki, Atsushi; Uchida, Giichiro; Setsuhara, Yuichi

    2015-03-01

    Molecular-structure variation of organic materials irradiated with atmospheric pressure He plasma jet have been investigated. Optical emission spectrum in the atmospheric-pressure He plasma jet has been measured. The spectrum shows considerable emissions of He lines, and the emission of O and N radicals attributed to air. Variation in molecular structure of Polyethylene terephthalate (PET) film surface irradiated with the atmospheric-pressure He plasma jet has been observed via X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR). These results via XPS and FT-IR indicate that the PET surface irradiated with the atmospheric-pressure He plasma jet was oxidized by chemical and/or physical effect due to irradiation of active species.

  16. Batch processing of overlapping molecular spectra as a tool for spatio-temporal diagnostics of power modulated microwave plasma jet

    Science.gov (United States)

    Voráč, Jan; Synek, Petr; Potočňáková, Lucia; Hnilica, Jaroslav; Kudrle, Vít

    2017-02-01

    Power modulated microwave plasma jet operating in argon at atmospheric pressure was studied by spatio-temporally resolved optical emission spectroscopy (OES) in order to clarify the influence of modulation on plasma parameters. OES was carried out in OH, NH, N2 and {{{N}}}2+ spectral regions using a spectrometer with intensified CCD detector synchronised with 101–103 Hz sine modulating signal. A special software, able to fit even the overlapping spectra, was developed to batch process the massive datasets produced by this spatio-temporal study. Results show that studied species with the exception of {{{N}}}2+ have balanced rotational and vibrational temperatures across the modulation frequencies. Significant influence of modulation can be clearly observed on temperature spatial gradients. Whereas for low modulation frequencies where the temperatures reach sharp maxima upon discharge tip, the high frequency modulation produces thermally homogeneous plasma.

  17. Process of commutation of a vacuum electric-discharge gap by laser plasma

    Energy Technology Data Exchange (ETDEWEB)

    Davydov, S. G., E-mail: asvi@mail.ru; Dolgov, A. N.; Kozlovskaya, T. I.; Revazov, V. O.; Seleznev, V. P.; Yakubov, R. Kh. [Dukhov All-Russian Research Institute of Automatics (Russian Federation)

    2016-01-15

    The temporal parameters of a process of vacuum gap commutation under exposure to a nanosecond pulse of laser radiation incident on the cathode has been studied depending on the radiation energy. Based on the experiment data, it is suggested that a glow discharge is initially ignited in electrode erosion products under exposure to the laser pulse, which due to development of the ionization-overheating instability undergoes the contraction of current channel and transits to an arc discharge. With the radiation energy exceeding a threshold value, the radiation (incident on the cathode) accelerates directly the instability development and the glow discharge transition to the arc discharge due to the radiation absorption in the discharge plasma.

  18. Prediction of chemical, physical and sensory data from process parameters for frozen cod using multivariate analysis

    DEFF Research Database (Denmark)

    Bechmann, Iben Ellegaard; Jensen, H.S.; Bøknæs, Niels

    1998-01-01

    Physical, chemical and sensory quality parameters were determined for 115 cod (Gadus morhua) samples stored under varying frozen storage conditions. Five different process parameters (period of frozen storage, frozen storage. temperature, place of catch, season for catching and state of rigor) were...... varied systematically at two levels. The data obtained were evaluated using the multivariate methods, principal component analysis (PCA) and partial least squares (PLS) regression. The PCA models were used to identify which process parameters were actually most important for the quality of the frozen cod....... PLS models that were able to predict the physical, chemical and sensory quality parameters from the process parameters of the frozen raw material were generated. The prediction abilities of the PLS models were good enough to give reasonable results even when the process parameters were characterised...

  19. Effect of q-nonextensive parameter and saturation time on electron density steepening in electron-positron-ion plasmas

    Science.gov (United States)

    Hashemzadeh, M.

    2015-11-01

    The effect of q-nonextensive parameter and saturation time on the electron density steepening in electron-positron-ion plasmas is studied by particle in cell method. Phase space diagrams show that the size of the holes, and consequently, the number of trapped particles strongly depends on the q-parameter and saturation time. Furthermore, the mechanism of the instability and exchange of energy between electron-positron and electric field is explained by the profiles of the energy density. Moreover, it is found that the q-parameter, saturation time, and electron and positron velocities affect the nonlinear evolution of the electron density which leads to the steepening of its structure. The q-nonextensive parameter or degree of nonextensivity is the relation between temperature gradient and potential energy of the system. Therefore, the deviation of q-parameter from unity indicates the degree of inhomogeneity of temperature or deviation from equilibrium. Finally, using the kinetic theory, a generalized q-dispersion relation is presented for electron-positron-ion plasma systems. It is found that the simulation results in the linear regime are in good agreement with the growth rate results obtained by the kinetic theory.

  20. Atmospheric pressure plasma processing of polymeric materials utilizing close proximity indirect exposure

    Energy Technology Data Exchange (ETDEWEB)

    Paulauskas, Felix L.; Bonds, Truman

    2016-09-20

    A plasma treatment method that includes providing treatment chamber including an intermediate heating volume and an interior treatment volume. The interior treatment volume contains an electrode assembly for generating a plasma and the intermediate heating volume heats the interior treatment volume. A work piece is traversed through the treatment chamber. A process gas is introduced to the interior treatment volume of the treatment chamber. A plasma is formed with the electrode assembly from the process gas, wherein a reactive species of the plasma is accelerated towards the fiber tow by flow vortices produced in the interior treatment volume by the electrode assembly.

  1. Design Rules and Electrical Parameters for a 90nm CMOS process

    DEFF Research Database (Denmark)

    Stassen, Flemming

    2007-01-01

    A set of fictitious simplified geometrical design rules and tables of electrical parameters are presented describing a 90nm CMOS process for educational purposes only.......A set of fictitious simplified geometrical design rules and tables of electrical parameters are presented describing a 90nm CMOS process for educational purposes only....

  2. OPTIMIZATION OF OPERATING PARAMETERS FOR EDM PROCESS BASED ON THE TAGUCHI METHOD AND ARTIFICIAL NEURAL NETWORK

    OpenAIRE

    A.Thillaivanan,; P. Asokan,; K.N.Srinivasan,; Saravanan, R.

    2010-01-01

    In this paper the complexity of electrical discharge machining process which is very difficult to determine optimal cutting parameters for improving cutting performance has been reported. Optimization of operating parameters is an important step in machining, particularly for operating unconventional machiningprocedure like EDM. A suitable selection of machining parameters for the electrical discharge machining process relies heavily on the operators’ technologies and experience because of th...

  3. Comparative analysis of the processing accuracy of high strength metal sheets by AWJ, laser and plasma

    Science.gov (United States)

    Radu, M. C.; Schnakovszky, C.; Herghelegiu, E.; Tampu, N. C.; Zichil, V.

    2016-08-01

    Experimental tests were carried out on two high-strength steel materials (Ramor 400 and Ramor 550). Quantification of the dimensional accuracy was achieved by measuring the deviations from some geometric parameters of part (two lengths and two radii). It was found that in case of Ramor 400 steel, at the jet inlet, the deviations from the part radii are quite small for all the three analysed processes. Instead for the linear dimensions, the deviations are small only in case of laser cutting. At the jet outlet, the deviations raised in small amount compared to those obtained at the jet inlet for both materials as well as for all the three processes. Related to Ramor 550 steel, at the jet inlet the deviations from the part radii are very small in case of AWJ and laser cutting but larger in case of plasma cutting. At the jet outlet, the deviations from the part radii are very small for all processes; in case of linear dimensions, there was obtained very small deviations only in the case of laser processing, the other two processes leading to very large deviations.

  4. Modeling of the coal gasification processes in a hybrid plasma torch

    Energy Technology Data Exchange (ETDEWEB)

    Matveev, I.B.; Serbin, S.I. [Applied Plasma Technology, Mclean, VA (USA)

    2007-12-15

    The major advantages of plasma treatment systems are cost effectiveness and technical efficiency. A new efficient electrodeless 1-MW hybrid plasma torch for waste disposal and coal gasification is proposed. This product merges several solutions such as the known inductive-type plasma torch, innovative reverse-vortex (RV) reactor and the recently developed nonequilibrium plasma pilot and plasma chemical reactor. With the use of the computational-fluid-dynamics-computational method, preliminary 3-D calculations of heat exchange in a 1-MW plasma generator operating with direct vortex and RV have been conducted at the air flow rate of 100 g/s. For the investigated mode and designed parameters, reduction of the total wall heat transfer for the reverse scheme is about 65 kW, which corresponds to an increase of the plasma generator efficiency by approximately 6.5%. This new hybrid plasma torch operates as a multimode, high power plasma system with a wide range of plasma feedstock gases and turn down ratio, and offers convenient and simultaneous feeding of several additional reagents into the discharge zone.

  5. Effects of process parameters on numerical control bending process for large diameter thin-walled aluminum alloy tubes

    Institute of Scientific and Technical Information of China (English)

    LI Cheng; YANG He; ZHAN Mei; XU Xu-dong; LI Guang-jun

    2009-01-01

    Numerical control(NC) bending experiments with different process parameters were carried out for 5052O aluminum alloy tubes with outer diameter of 70 mm, wall thickness of 1.5 mm, and centerline bending radius of 105 mm. And the effects of process parameters on tube wall thinning and cross section distortion were investigated. Meanwhile, acceptable bending of the 5052O aluminum tubes was accomplished based on the above experiments. The results show that the effects of process parameters on bending process for large diameter thin-walled aluminum alloy tubes are similar to those for small diameter thin-walled tubes, but the forming quality of the large diameter thin-walled aluminum alloy tubes is much more sensitive to the process parameters and thus it is more difficult to form.

  6. Plasma processes and applications in NanoBiotechnology

    Energy Technology Data Exchange (ETDEWEB)

    Rossi, F; Colpo, P, E-mail: francois.rossi@jrc.ec.europa.eu [European Commission, Joint Research Centre, Institute for Health and Consumer Protection (IHCP), I-21020, Ispra (Italy)

    2010-11-01

    Nanostructured surfaces presenting chemical or topographical patterns are now being increasingly developed in nanobiotechnology. Major applications are related to cell culture models and biodetection. We show that plasma technologies, in particular the combination plasma polymers deposition and etching, together with colloidal lithography, e-beam lithography and microcontact printing, are essential tools to produce nanostructured surfaces. We show that chemical and topographical patterns can be obtained on different substrates, with dimensions down to some 10 nm. The applications of these nanostructured surfaces in biology and bio-detection are reviewed and the advantages and limitation of the techniques underlined.

  7. Plasma Surface Treatment of Powder Materials — Process and Application

    Directory of Open Access Journals (Sweden)

    Monika Pavlatová

    2012-01-01

    Full Text Available Polyolefin particles are hydrophobic, and this prevents their use for various applications. Plasma treatment is an environment-friendly polyolefin hydrophilisation method. We developed an industrial-scale plant for plasma treatment of particles as small as micrometers in diameter. Materials such as PE waxes, UHMWPE and powders for rotomolding production were tested to verify their new surface properties. We achieved significantly increased wettability of the particles, so that they are very easily dispersive in water without agglomeration, and their higher surface energy is retained even after sintering in the case of rotomolding powders.

  8. Plasma proteins as biomarkers of the aging process.

    Science.gov (United States)

    Vranckx, R; Savu, L; Lambert, N; de Conchard, G V; Grosse, R; Mourey, M S; Corman, B

    1995-02-01

    This study was designed to characterize the rat serum proteins as biomarkers of the normal aging process. Crossed immunoelectrophoresis or electroimmunodiffusion quantitation of proteins was performed in rats aged 6, 12, 24, and 30 mo. Selection of healthy animals was based on confrontation of crossed immunoelectrophoresis patterns with those of experimentally inflamed young adults and with individual anatomopathological data. Convergence of inflammatory patterns and severe histological lesions was the exclusion criterion. Senescence-induced decrease was demonstrated for eight proteins [negative senescence reactants (SRs-)] and increase for six proteins [positive SRs (SRs+)]. Most SRs belonged to the class of proteins responsive to acute inflammation [acute phase reactants (APRs)]. One SR+, the thyroxine-binding globulin, a high-affinity thyroid hormone binder, emerged as a particularly reliable senescence biomarker, showing the highest aging-related variation (8-fold increase from 6 to 30 mo) and not belonging to the APR class. Chronic treatment with perindopril, an angiotensin I-converting enzyme inhibitor used in heart and renal disease therapy, significantly enhanced thyroxine-binding capacity, possibly by preventing age-related alterations of serum lipids. Serum protein patterns prove valuable both as indexes for selecting aging animals free from superimposed pathologies and as parameters of senescence-induced changes in protein biosynthesis.

  9. Interaction of CLAM Steel with Plasma in HT-7 Tokamak During High Parameter Operation

    Institute of Scientific and Technical Information of China (English)

    LI Chunjing; HUANG Qunying; FENG Yan; LI Jiangang; KONG Mingguang

    2007-01-01

    A Plasma Surface Interaction(PSI)experiment on China Low Activation Martensitic(CLAM)steel was done to check if CLAM steel could be used as a Plasma Facing Material (PFM).A specimen with a diameter of 45 mm was exposed to 897 shots of deuterium plasmas with a total duration of 712 sec at a minor radius of 30 cm in HT-7 tokamak.During the exposure experiment,no observable influence Was found on plasma performance.After exposure,the surface of the specimen seemed as smooth as before but with some colour change at the margin of the specimen.Even though some micro-damage,such as dense blisters,melting,splashing,depositions,and dust,Was found on local surfaces with Scanning Electron Microscopic(SEM)observation.The reflectivity of the specimen decreased only slightly.All of these shows CLAM steel has good stability and irradiation resistance.With further optimization,it could possibly be used as the first mirror material for plasma diagnostics in tokamaks.

  10. Research on the Plasma Spray Process Applying the Finite Element Method

    Directory of Open Access Journals (Sweden)

    Raimonda Lukauskaitė

    2015-03-01

    Full Text Available The article investigates the physical processes of plasma spraying. The application of the finite element method has assisted in establishing the distribution of the voltage of the plasma arc and current density in the plasma stream during numerical simulation. With reference to the results of experimental data, the real location of an anode spot of the electric arc in the plasma spray process has been evaluated. The paper has calculated the values of electromagnetic Lorentz forces and established their influence on plasma flow. With the help of the two-layer model for the semi-molten nickel particle, contact between the particle and substrate during plasma spraying has been simulated.

  11. Influence of radiative processes on the ignition of deuterium–tritium plasma containing inactive impurities

    Energy Technology Data Exchange (ETDEWEB)

    Gus’kov, S. Yu., E-mail: guskov@sci.lebedev.ru [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation); Sherman, V. E. [Peter the Great St. Petersburg Polytechnic University (Russian Federation)

    2016-08-15

    The degree of influence of radiative processes on the ignition of deuterium–tritium (DT) plasma has been theoretically studied as dependent on the content of inactive impurities in plasma. The analytic criterion of plasma ignition in inertial confinement fusion (ICF) targets is modified taking into account the absorption of intrinsic radiation from plasma in the ignition region. The influence of radiative processes on the DT plasma ignition has been analytically and numerically studied for plasma that contains a significant fraction of inactive impurities either as a result of DT fuel mixing with ICF target ablator material or as a result of using light metal DT-hydrides as solid noncryogenic fuel. It has been shown that the effect of the absorption of intrinsic radiation leads to lower impurity-induced increase in the ignition energy as compared to that calculated in the approximation of optically transparent ignition region.

  12. Influence of radiative processes on the ignition of deuterium-tritium plasma containing inactive impurities

    Science.gov (United States)

    Gus'kov, S. Yu.; Sherman, V. E.

    2016-08-01

    The degree of influence of radiative processes on the ignition of deuterium-tritium (DT) plasma has been theoretically studied as dependent on the content of inactive impurities in plasma. The analytic criterion of plasma ignition in inertial confinement fusion (ICF) targets is modified taking into account the absorption of intrinsic radiation from plasma in the ignition region. The influence of radiative processes on the DT plasma ignition has been analytically and numerically studied for plasma that contains a significant fraction of inactive impurities either as a result of DT fuel mixing with ICF target ablator material or as a result of using light metal DT-hydrides as solid noncryogenic fuel. It has been shown that the effect of the absorption of intrinsic radiation leads to lower impurity-induced increase in the ignition energy as compared to that calculated in the approximation of optically transparent ignition region.

  13. Application of Atmospheric-Pressure Microwave Line Plasma for Low Temperature Process

    Science.gov (United States)

    Suzuki, Haruka; Nakano, Suguru; Itoh, Hitoshi; Sekine, Makoto; Hori, Masaru; Toyoda, Hirotaka

    2015-09-01

    Atmospheric pressure (AP) plasmas have been given much attention because of its high cost benefit and a variety of possibilities for industrial applications. In various kinds of plasma production technique, pulsed-microwave discharge plasma using slot antenna is attractive due to its ability of high-density and stable plasma production. In this plasma source, however, size of the plasma has been limited up to a few cm in length due to standing wave inside a waveguide. To solve this, we have proposed a newly-developed AP microwave plasma source that utilizes not standing wave but travelling wave. By using this plasma source, spatially-uniform AP line plasma with 40 cm in length was realized by pure helium discharge in 60 cm slot and with nitrogen gas additive of 1%. Furthermore, gas temperature as low as 400 K was realized in this device. In this study, as an example of low temperature processes, hydrophilic treatment of PET films was performed. Processing speed increased with pulse frequency and a water contact angle of ~20° was easily obtained within 5 s with no thermal damage to the substrate. To evaluate treatment-uniformity of long line length, PET films were treated by 90 cm slot-antenna plasma and uniform treatment performance was confirmed.

  14. Relationships Between Process Parameters, Microstructure, and Adhesion Strength of HVOF Sprayed IN718 Coatings

    Science.gov (United States)

    Lyphout, Christophe; Nylén, Per; Östergren, Lars

    2011-01-01

    Fundamental understanding of relationships between process parameters, particle in-flight characteristics, and adhesion strength of HVOF sprayed coatings is important to achieve the high coating adhesion that is needed in aeronautic repair applications. In this study, statistical Design of Experiments (DoE) was used to identify the most important process parameters that influence adhesion strength of IN718 coatings sprayed on IN718 substrates. Special attention was given to the parameters combustion ratio, total gas mass flow, stand-off distance and external cooling, since these parameters were assumed to have a significant influence on particle temperature and velocity. Relationships between these parameters and coating microstructure were evaluated to fundamentally understand the relationships between process parameters and adhesion strength.

  15. Comparison endpoint study of process plasma and secondary electron beam exciter optical emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Stephan Thamban, P. L.; Yun, Stuart; Padron-Wells, Gabriel; Hosch, Jimmy W.; Goeckner, Matthew J. [Department of Mechanical Engineering, University of Texas at Dallas, 800W Campbell Road, Richardson, Texas 75080 (United States); Department of Electrical Engineering, University of Texas at Dallas, 800W Campbell Road, Richardson, Texas 75080 (United States); Verity Instruments, Inc., 2901 Eisenhower Street, Carrollton, Texas 75007 (United States); Department of Mathematical Sciences, University of Texas at Dallas, 800 W Campbell Road, Richardson, Texas 75080 (United States)

    2012-11-15

    Traditionally process plasmas are often studied and monitored by optical emission spectroscopy. Here, the authors compare experimental measurements from a secondary electron beam excitation and direct process plasma excitation to discuss and illustrate its distinctiveness in the study of process plasmas. They present results that show excitations of etch process effluents in a SF{sub 6} discharge and endpoint detection capabilities in dark plasma process conditions. In SF{sub 6} discharges, a band around 300 nm, not visible in process emission, is observed and it can serve as a good indicator of etch product emission during polysilicon etches. Based on prior work reported in literature the authors believe this band is due to SiF{sub 4} gas phase species.

  16. Elementary Processes and Kinetic Modeling for Hydrogen and Helium Plasmas

    Directory of Open Access Journals (Sweden)

    Roberto Celiberto

    2017-05-01

    Full Text Available We report cross-sections and rate coefficients for excited states colliding with electrons, heavy particles and walls useful for the description of H 2 /He plasma kinetics under different conditions. In particular, the role of the rotational states in resonant vibrational excitations of the H 2 molecule by electron impact and the calculation of the related cross-sections are illustrated. The theoretical determination of the cross-section for the rovibrational energy exchange and dissociation of H 2 molecule, induced by He atom impact, by using the quasi-classical trajectory method is discussed. Recombination probabilities of H atoms on tungsten and graphite, relevant for the determination of the nascent vibrational distribution, are also presented. An example of a state-to-state plasma kinetic model for the description of shock waves operating in H 2 and He-H 2 mixtures is presented, emphasizing also the role of electronically-excited states in affecting the electron energy distribution function of free electrons. Finally, the thermodynamic properties and the electrical conductivity of non-ideal, high-density hydrogen plasma are finally discussed, in particular focusing on the pressure ionization phenomenon in high-pressure high-temperature plasmas.

  17. Plasma processing of fibre materials for enhanced impact protection

    NARCIS (Netherlands)

    Creyghton, Y.L.M.; Simor, M.

    2009-01-01

    The performance of lightweight impact protective clothing depends on the constituting materials, their assembly in a system and interaction under various dynamic impact conditions. In this paper an overview of options for improved impact protective clothing systems based on a new plasma technology i

  18. Plasma processing of fibre materials for enhanced impact protection

    NARCIS (Netherlands)

    Creyghton, Y.L.M.; Simor, M.

    2009-01-01

    The performance of lightweight impact protective clothing depends on the constituting materials, their assembly in a system and interaction under various dynamic impact conditions. In this paper an overview of options for improved impact protective clothing systems based on a new plasma technology i

  19. Plasma processing of fibre materials for enhanced impact protection

    NARCIS (Netherlands)

    Creyghton, Y.L.M.; Simor, M.

    2009-01-01

    The performance of lightweight impact protective clothing depends on the constituting materials, their assembly in a system and interaction under various dynamic impact conditions. In this paper an overview of options for improved impact protective clothing systems based on a new plasma technology

  20. Instability Parameters of Optical Oscillation Frequency in Plasma Central Discharge and Periphery Region

    Institute of Scientific and Technical Information of China (English)

    ZHOU Zhu-Wen; M.A.LIEBERMAN; Sungjin KIM

    2006-01-01

    @@ We have observed relaxation oscillations in a capacitive discharge in Ar gas, connected to a peripheral ground chamber. The plasma oscillations observed from time-varying optical emission from the main discharge chamber show, for example, a high frequency (75.37kHz) relaxation oscillation, at 100mTorr and 8 W absorbed power,and a low frequency (2.72 Hz) relaxation oscillation, 100mTorr and 325 W absorbed power. Time-varying optical emission intensity and plasma density are also detected with a Langmuir probe. The theoretical result agrees well with experiments.

  1. Characterization of Nuclease Activity in Human Seminal Plasma and its Relationship to Semen Parameters, Sperm DNA Fragmentation and Male Infertility.

    Science.gov (United States)

    Fernandez-Encinas, Alba; García-Peiró, Agustí; Ribas-Maynou, Jordi; Abad, Carlos; Amengual, María José; Navarro, Joaquima; Benet, Jordi

    2016-01-01

    Some studies have shown that complementary biomarkers are needed in semen analysis to provide a more accurate diagnosis for couples with infertility problems. To our knowledge no study has been done to determine the relationships among nuclease activity in seminal plasma, semen parameters, sperm DNA fragmentation and male infertility. A total of 94 semen samples were collected according to WHO 2010 semen analysis parameters. Samples were analyzed using the single radial enzyme diffusion method for nuclease activity in seminal plasma, and alkaline and neutral Comet assay for sperm DNA fragmentation. Samples were obtained from 11 fertile donors with proven fertility, 17 patients with normozoospermia in an infertile couple, and 16 patients with asthenozoospermia, 19 with teratozoospermia, 21 with asthenoteratozoospermia and 10 with azoospermia. Nuclease activity analyzed in seminal plasma was higher in patients than in controls. It correlated with sperm motility and morphology, and sperm DNA fragmentation measured by the alkaline Comet assay. No correlation with sperm DNA fragmentation was measured by the neutral Comet assay. ROC curves to determine male infertility revealed 0.658 sensitivity, 0.727 specificity and 0.705 cm(2) AUC for the single radial enzyme diffusion method, 0.918, 1 and 0.994 cm(2) for the alkaline Comet assay, and 0.917, 0.250 and 0.373 cm(2), respectively, for the neutral Comet assay. Nuclease activity in seminal plasma corrected by sperm count is a good variable to predict male infertility. Results indicate that it could be a useful complementary parameter for male infertility diagnosis. Copyright © 2016 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  2. Optimization of Friction Welding Process Parameters for Joining Carbon Steel and Stainless Steel%Optimization of Friction Welding Process Parameters for Joining Carbon Steel and Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    R Paventhan; P R Lakshminarayanan; V Balasubramanian

    2012-01-01

    Friction weIding is a solid state joining process used extensively currently owing to its advantages such as low heat input, high production efficiency, ease of manufacture, and environment friendliness. Materials difficult to be welded by fusion welding processes can be successfully welded by friction welding. An attempt was made to develop an empirical relationship to predict the tensile strength of friction welded AISI 1040 grade medium carbon steel and AISI 304 austenitic stainless steel, incorporating the process parameters such as friction pressure, forging pressure, friction time and forging time, which have great influence on strength of the joints. Response surface methodology was applied to optimize the friction welding process parameters to attain maximum tensile strength of the joint. The maximum tensile strength of 543 MPa could be obtained for the joints fabricated under the welding conditions of friction pressure of 90 MPa, forging pressure of 90 MPa, friction time of 6 s and forging time of 6 s.

  3. Scrutiny of plasma spraying complexities with case study on the optimized conditions toward coating process control

    Directory of Open Access Journals (Sweden)

    Ridha Djebali

    2015-09-01

    Full Text Available In the present study, we investigate a PSP using the Jets&Poudres soft. The plasma gas understanding is given to highlight the effects of gas mixtures proportions on diffusion parameters. An overview on the process complexities at main subsystems is given with focus on Argon plasma and optimal mixing; the powder acceleration and heat-up modeling are also presented. Under literature conditions and for He–Ar–H2 65–30–5% gas, it was found that the droplet's primary way is to coat. The used ternary mixture gives superior efficiency compared to the pure Argon which shows a prior way to rebound. Moreover, medium particles (dp≈45 µm present the high deposited rate among the splashed mass, a 100% molten ratio is observed for the small powder and only particles of size below 40.3 µm have evaporated, particles of initial diameter between 40.3 and 49 µm are fully molten and all particles above 71.9 µm are fully solid. The coat formed by the deposited mass will transfer a large amount of heat to the substrate (9–58 MW/m2. The crushed particle's rate is about 4% from the investigated number and the average fully molten particle's rate is about 72% and the rest of particles arrive in solid sate.

  4. Investigation of physical processes limiting plasma density in H-mode on DIII-D

    Energy Technology Data Exchange (ETDEWEB)

    Maingi, R.; Mahdavi, M.A. [General Atomics, San Diego, CA (United States); Jernigan, T.C. [Oak Ridge National Lab., TN (United States)] [and others

    1996-12-01

    A series of experiments was conducted on the DIII-D tokamak to investigate the physical processes which limit density in high confinement mode (H-mode) discharges. The typical H-mode to low confinement mode (L-mode) transition limit at high density near the empirical Greenwald density limit was avoided by divertor pumping, which reduced divertor neutral pressure and prevented formation of a high density, intense radiation zone (MARFE) near the X-point. It was determined that the density decay time after pellet injection was independent of density relative to the Greenwald limit and increased non-linearly with the plasma current. Magnetohydrodynamic (MHD) activity in pellet-fueled plasmas was observed at all power levels, and often caused unacceptable confinement degradation, except when the neutral beam injected (NBI) power was {le} 3 MW. Formation of MARFEs on closed field lines was avoided with low safety factor (q) operation but was observed at high q, qualitatively consistent with theory. By using pellet fueling and optimizing discharge parameters to avoid each of these limits, an operational space was accessed in which density {approximately} 1.5 {times} Greenwald limit was achieved for 600 ms, and good H-mode confinement was maintained for 300 ms of the density flattop. More significantly, the density was successfully increased to the limit where a central radiative collapse was observed, the most fundamental density limit in tokamaks.

  5. Nonlinear plasma processes and the formation of electron kappa distribution

    Science.gov (United States)

    Yoon, Peter

    2016-07-01

    The goal of nonequilibrium statistical mechanics is to establish fundamental relationship between the time irreversible macroscopic dynamics and the underlying time reversible behavior of microscopic system. The paradigm of achieving this seemingly paradoxical goal is through the concept of probability. For classical systems Boltzmann accomplished this through his H theorem and his kinetic equation for dilute gas. Boltzmann's H function is the same as classical extensive entropy aside from the minus sign, and his kinetic equation is applicable for short-range molecular interaction. For plasmas, the long-range electromagnetic force dictates the inter-particular interaction, and the underlying entropy is expected to exhibit non-extensive, or non-additive behavior. Among potential models for the non-additive entropy, the celebrated Tsallis entropy is the most well known. One of the most useful fundamental kinetic equations that governs the long-range plasma interaction is that of weak turbulence kinetic theory. At present, however, there is no clear-cut connection between the Tsallis entropy and the kinetic equations that govern plasma behavior. This can be contrasted to Boltzmann's H theorem, which is built upon his kinetic equation. The best one can do is to show that the consequences of Tsallis entropy and plasma kinetic equation are the same, that is, they both imply kappa distribution. This presentation will overview the physics of electron acceleration by beam-generated Langmuir turbulence, and discuss the asymptotic solution that rigorously can be shown to correspond to the kappa distribution. Such a finding is a strong evidence, if not water-tight proof, that there must be profound inter-relatioship between the Tsallis thermostatistical theory and the plasma kinetic theory.

  6. Achieving atomistic control in materials processing by plasma-surface interactions

    Science.gov (United States)

    Chang, Jeffrey; Chang, Jane P.

    2017-06-01

    The continuous down-scaling of electronic devices and the introduction of functionally improved novel materials require a greater atomic level controllability in the synthesis and patterning of thin film materials, especially with regards to deposition uniformity and conformality as well as etching selectivity and anisotropy. The richness of plasma chemistry and the corresponding plasma-surface interactions provide the much needed processing flexibility and efficacy. To achieve the integration of the novel materials into devices, plasma-enhanced atomic layer processing techniques are emerging as the enabling factors to obtain atomic scale control of complex materials and nanostructures. This review focuses on an overview of the role of respective plasma species involved in plasma-surface interactions, addressing their respective and synergistic effects, which is followed by two distinct applications: plasma-enhanced atomic layer deposition (ALD) and atomic layer etching (ALE). For plasma-enhanced ALD, this review emphasizes the use of plasma chemistry to enable alternative pathways to synthesize complex materials at low temperatures and the challenges associated with deposition conformality. For plasma enabled ALE processes, the review focuses on the surface-specific chemical reactions needed to achieve desirable selectivity and anisotropy.

  7. Tech-X Corporation releases simulation code for solving complex problems in plasma physics : VORPAL code provides a robust environment for simulating plasma processes in high-energy physics, IC fabrications and material processing applications

    CERN Multimedia

    2005-01-01

    Tech-X Corporation releases simulation code for solving complex problems in plasma physics : VORPAL code provides a robust environment for simulating plasma processes in high-energy physics, IC fabrications and material processing applications

  8. Synthetically quantitative evaluation function of characteristic parameters on CO2 arc welding process

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The statistical probability and their variation regularity of the measurable characteristic parameters in the CO2 arc welding droplet short-circuiting transfer process have been studied. The statistical analysis shows that the sensitivity of each characteristic parameter with regard to the variation of the short-circuiting transfer process is different. The sensitivity of 4 kinds among these characteristic parameters is more intense than that of the short-circuiting transfer frequency. In order to take account of the synthetic influence of these characteristic parameters, by means of the characteristic parameters synthetic value, a quantitative evaluation function is built up to describe and evaluate the short-circuiting transfer process of CO2 arc welding in real time. The testing shows that the evaluation function can give a suitable synthetic valuation for the short-circuiting transfer process with a variety of welding variables.

  9. Relationships between the Processing Parameters of Melt Blown Nonwoven Fabric and Its Structure and Filtration Property

    Institute of Scientific and Technical Information of China (English)

    潘莺; 王善元

    2001-01-01

    Based on the processing experiment and sodium flame test this paper deals with the relationship between processing parameters, structure, and filtration property of melt blown fabric. Through the image analysis of Questar micro-images in combination with the SEM observation and the measurement of some macrostructure indices, the relationship between the processing parameters and the structure especially the microstructure is emphasized Finally the effect of somestructure factors on filtration properties is discussed theoretically.

  10. Up-scaling the production of modified a-C:H coatings in the framework of plasma polymerization processes

    Science.gov (United States)

    Corbella, C.; Bialuch, I.; Kleinschmidt, M.; Bewilogua, K.

    2009-10-01

    Hydrogenated amorphous carbon (a-C:H) films with silicon and oxygen additions, which exhibit mechanical, tribological and wetting properties adequate for protective coating performance, have been synthesized at room temperature in a small- (0.1 m 3) and a large-scale (1 m 3) coaters by low-pressure Plasma-Activated Chemical Vapour Deposition (PACVD). Hence, a-C:H:Si and a-C:H:Si:O coatings were produced in atmospheres of tetramethylsilane (TMS) and hexamethyldisiloxane (HMDSO), respectively, excited either by radiofrequency (RF - small scale) or by pulsed-DC power (large scale). Argon was employed as a carrier gas to stabilize the glow discharge. Several series of 2-5 μm thick coatings have been prepared at different mass deposition rates, Rm, by varying total gas flow, F, and input power, W. Arrhenius-type plots of Rm/ F vs. ( W/ F) -1 show linear behaviours for both plasma reactors, as expected for plasma polymerization processes at moderated energies. The calculation of apparent activation energy, Ea, in each series permitted us to define the regimes of energy-deficient and monomer-deficient PACVD processes as a function of the key parameter W/ F. Moreover, surface properties of the modified a-C:H coatings, such as contact angle, abrasive wear rate and hardness, appear also correlated to this parameter. This work shows an efficient methodology to scale up PACVD processes from small, lab-scale plasma machines to industrial plants by the unique evaluation of macroscopic parameters of deposition.

  11. VUV diagnostic of electron impact processes in low temperature molecular hydrogen plasma

    CERN Document Server

    Komppula, J

    2015-01-01

    Novel methods for diagnostics of molecular hydrogen plasma processes, such as ionization, production of high vibrational levels, dissociation of molecules via excitation to singlet and triplet states and production of metastable states, are presented for molecular hydrogen plasmas in corona equilibrium. The methods are based on comparison of rate coefficients of plasma processes and optical emission spectroscopy of lowest singlet and triplet transitions, i.e. Lyman-band ($B^1\\Sigma^+_u \\rightarrow X^1\\Sigma^+_g$) and molecular continuum ($a^3\\Sigma^+_g \\rightarrow b^3\\Sigma^+_u$), of the hydrogen molecule in VUV wavelength range. Comparison of rate coefficients of spin-allowed and/or spin-forbidden excitations reduces the uncertainty caused by the non-equilibrium distributions of electron energy and molecular vibrational level, which are typically known poorly in plasma sources. The described methods are applied to estimate the rates of various plasma processes in a filament arc discharge.

  12. A Multi-Parameter Optimization of Plasma Density for an Advanced Linear Collider*

    CERN Document Server

    Muggli, P; Hillenbrand, S

    2011-01-01

    Recent plasma wakefield accelerator (PWFA) experiments showed that an accelerating gradient as high as 50 GV/m can be driven and sustained over a meter-long plasma [1]. Based on this result, a straw man design for a future, multi-stage, PWFA-based electron/positron collider with an energy gain of ~ 25 GeV/stage has been generated [2]. However, the choice of plasma density remains open. On one hand, high density means large accelerating gradients and possibly a shorter collider. On the other it means that the accelerating structure dimensions become very small, on the order of the plasma wavelength. Operating at high gradient and with such small structure imposes very strong constraints on the particle bunches: small dimensions and spacing, large current or limited charge, etc. These constraints result is challenges in producing the bunches (compression, shaping for optimum loading, etc.) and could limit the achievable collider luminosity. We explore the global implications of operating at a lower accelerating...

  13. The effect of plasma fluctuations on parallel transport parameters in the SOL

    DEFF Research Database (Denmark)

    Havlíčková, E.; Fundamenski, W.; Naulin, Volker

    2011-01-01

    in the scrape-off layer (SOL) taking into account these fluctuations is presented. Plasma transport in the SOL along the magnetic field between two targets is calculated by a one-dimensional fluid code in order to estimate the response to transient conditions along the SOL and the attention is given...

  14. Evolution of the plasma parameters in the expanding laser ablation plume of silver

    DEFF Research Database (Denmark)

    Christensen, Bo Toftmann; Schou, Jørgen; Hansen, T.N.;

    2002-01-01

    The angular and radial variation of the ion density and electron temperature in the plasma plume produced by laser ablation of silver at fluences of 0.8-1.3 J cm(-2) at 355 nm have been studied using a time-resolving Langmuir probe. The angular dependence of the electron temperature and the magni...

  15. T3PS v1.0: Tool for Parallel Processing in Parameter Scans

    Science.gov (United States)

    Maurer, Vinzenz

    2016-01-01

    T3PS is a program that can be used to quickly design and perform parameter scans while easily taking advantage of the multi-core architecture of current processors. It takes an easy to read and write parameter scan definition file format as input. Based on the parameter ranges and other options contained therein, it distributes the calculation of the parameter space over multiple processes and possibly computers. The derived data is saved in a plain text file format readable by most plotting software. The supported scanning strategies include: grid scan, random scan, Markov Chain Monte Carlo, numerical optimization. Several example parameter scans are shown and compared with results in the literature.

  16. Comparisons of Simulated and Observed Stormtime Magnetic Intensities and Ion Plasma Parameters in the Ring Current

    Science.gov (United States)

    Chen, M. W.; Guild, T. B.; Lemon, C.; Roeder, J. L.; Le, G.; Schulz, M.

    2009-12-01

    Recent progress in ring current and plasma sheet modeling has shown the importance of a self-consistent treatment of particle transport and magnetic and electric fields in the inner magnetosphere. Models with and without self-consistency can lead to significantly different magnitudes and spatial distributions of plasma pressure and magnetic intensity during disturbed times. In this study we compare simulated and observed stormtime magnetic intensities (GOES and Polar/MFE) and ion densities (LANL/MPA and Polar/CAMMICE) to test how well self-consistent simulations can simultaneously reproduce these quantities. We simulate the ring current and plasma sheet for conditions corresponding to the 11 August 2000 storm using the self-consistent Rice Convection Model-Equilibrium (RCM-E) [Lemon et al., JGR, 2004] with a constant magnetopause location. Using the empirical IMF-dependent model of Tsyganenko and Mukai [JGR, 2003], we specify the plasma sheet pressure and density at 10 RE as the plasma boundary location in the RCM-E. The simulated ion densities at different magnetic local times agree fairly well with those from the re-analysis model of LANL/MPA densities of O’Brien and Lemon [Space Weather, 2007]. We compare the simulated magnetic intensity with the magnetic intensity measured by magnetometers on the GOES satellites at geosynchronous altitude (6.6 RE) and on the Polar satellite. Agreement between the simulated and observed magnetic intensities tends to agree better on the nightside than on the dayside in the inner magnetosphere. In particular, the model cannot account for observed drops in the dayside magnetic intensity during decreases in the solar wind pressure. We will modify the RCM-E to include a time-varying magnetopause location to simulate compressions and expansions associated with variations in the solar wind pressure. We investigate whether this will lead to improved agreement between the simulated and model magnetic intensities.

  17. Association of Irisin Plasma Levels with Anthropometric Parameters in Children with Underweight, Normal Weight, Overweight, and Obesity

    Directory of Open Access Journals (Sweden)

    Leticia Elizondo-Montemayor

    2017-01-01

    Full Text Available The correlations between irisin levels, physical activity, and anthropometric measurements have been extensively described in adults with considerable controversy, but little evidence about these relationships has been found in children. The objective of this study is to correlate the plasma levels of irisin in underweight, normal weight, overweight, and obese children with anthropometric parameters and physical activity levels. A cross-sample of 40 children was divided into the following groups on the basis of body mass index (BMI percentile. The correlations of plasma irisin levels with physical activity, anthropometric, and metabolic measurements were determined. Plasma irisin levels (ng/mL were lower for the underweight group (164.2 ± 5.95 than for the normal weight and obese groups (182.8 ± 5.58; p<0.05. Irisin levels correlated positively with BMI percentile (0.387, waist circumference (0.373, and fat-free mass (0.353; p<0.05, but not with body muscle mass (−0.027. After a multiple linear regression analysis, only BMI percentile (0.564; p<0.008 showed a positive correlation with irisin. Our results indicated no association with metabolic parameters. A negative correlation with physical activity was observed. Interrelationships among body components might influence irisin levels in children.

  18. Development of atmospheric pressure plasma processing machine tool for large aperture optics

    Science.gov (United States)

    Su, Xing; Wu, Yangong; Zhang, Peng; Xin, Qiang; Wang, Bo

    2016-10-01

    In recent years, major projects, such as National Ignition Facility and Laser Mégajoule, have generated great demands for large aperture optics with high surface accuracy and low Subsurface Damage (SSD) at the mean time. In order to remove SSD and improve surface quality, optics is fabricated by sub-aperture polishing. However, the efficiency of the sub-aperture polishing has been a bottleneck step for the optics manufacturing. Atmospheric Pressure Plasma Processing (APPP) as an alternate method offers high potential for speeding up the polishing process. This technique is based on chemical etching, hence there is no physical contact and no damage is induced. In this paper, a fast polishing machine tool is presented which is designed for fast polishing of the large aperture optics using APPP. This machine tool employs 3PRS-XY hybrid structure as its framework. There is a platform in the 3PRS parallel module to support the plasma generating system. And the large work piece is placed on the XY stage. In order to realize the complex motion trajectory for polishing the freeform optics, five axis of the tool operate simultaneously. To overcome the complexity of inverse kinematics calculation, a dedicated motion control system is also designed for speeding up the motion response. For high removal rate, the individual influence of several key processing parameters is investigated. And under specific production condition, this machine tool offers a high material over 30mm3/min for fused silica substrates. This results shows that APPP machine tool has a strong potential for fast polishing large optics without introducing SSD.

  19. Numerical simulation of the coal combustion process initiated by a plasma source

    Science.gov (United States)

    Askarova, A. S.; Messerle, V. E.; Ustimenko, A. B.; Bolegenova, S. A.; Maksimov, V. Yu.

    2014-12-01

    Numerical experiments on the torch combustion of the coal dust prepared by a plasma-thermochemical treatment for combustion have been done using the method of three-dimensional simulation. It is shown that the plasma preparation of coal for combustion enables one to optimize the process, improve the conditions for inflammation and combustion and minimize the emissions of harmful substances.

  20. Data processing of absorption spectra from photoionized plasma experiments at Z

    Energy Technology Data Exchange (ETDEWEB)

    Hall, I. M.; Durmaz, T.; Mancini, R. C. [Department of Physics, University of Nevada, Reno, Nevada 89557 (United States); Bailey, J. E.; Rochau, G. A. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1196 (United States)

    2010-10-15

    We discuss the processing of x-ray absorption spectra from photoionized plasma experiments at Z. The data was recorded with an imaging spectrometer equipped with two elliptically bent potassium acid phthalate (KAP) crystals. Both time-integrated and time-resolved data were recorded. In both cases, the goal is to obtain the transmission spectra for quantitative analysis of plasma conditions.

  1. Influence of Discharge Parameters on Tuned Substrate Self-Bias in an Radio-Frequency Inductively Coupled Plasma

    Institute of Scientific and Technical Information of China (English)

    Ding Zhenfeng; Sun Jingchao; Wang Younian

    2005-01-01

    The tuned substrate self-bias in an rf inductively coupled plasma source is controlled by means of varying the impedance of an external LC network inserted between the substrate and the ground. The influencing parameters such as the substrate axial position, different coupling coils and inserted resistance are experimentally studied. To get a better understanding of the experimental results, the axial distributions of the plasma density, electron temperature and plasma potential are measured with an rf compensated Langmuir probe; the coil rf peak-to-peak voltage is measured with a high voltage probe. As in the case of changing discharge power, it is found that continuity, instability and bi-stability of the tuned substrate bias can be obtained by means of changing the substrate axial position in the plasma source or the inserted resistance. Additionally,continuity can not transit directly into bi-stability, but evolves via instability. The inductance of the coupling coil has a substantial effect on the magnitude and the property of the tuned substrate bias.

  2. Probabilistic parameter estimation of activated sludge processes using Markov Chain Monte Carlo.

    Science.gov (United States)

    Sharifi, Soroosh; Murthy, Sudhir; Takács, Imre; Massoudieh, Arash

    2014-03-01

    One of the most important challenges in making activated sludge models (ASMs) applicable to design problems is identifying the values of its many stoichiometric and kinetic parameters. When wastewater characteristics data from full-scale biological treatment systems are used for parameter estimation, several sources of uncertainty, including uncertainty in measured data, external forcing (e.g. influent characteristics), and model structural errors influence the value of the estimated parameters. This paper presents a Bayesian hierarchical modeling framework for the probabilistic estimation of activated sludge process parameters. The method provides the joint probability density functions (JPDFs) of stoichiometric and kinetic parameters by updating prior information regarding the parameters obtained from expert knowledge and literature. The method also provides the posterior correlations between the parameters, as well as a measure of sensitivity of the different constituents with respect to the parameters. This information can be used to design experiments to provide higher information content regarding certain parameters. The method is illustrated using the ASM1 model to describe synthetically generated data from a hypothetical biological treatment system. The results indicate that data from full-scale systems can narrow down the ranges of some parameters substantially whereas the amount of information they provide regarding other parameters is small, due to either large correlations between some of the parameters or a lack of sensitivity with respect to the parameters.

  3. INFLUENCE OF PROCESS PARAMETERS ON DIMENSIONAL ACCURACY OF PARTS MANUFACTURED USING FUSED DEPOSITION MODELLING TECHNOLOGY

    Directory of Open Access Journals (Sweden)

    Filip Górski

    2013-09-01

    Full Text Available The paper presents the results of experimental study – part of research of additive technology using thermoplastics as a build material, namely Fused Deposition Modelling (FDM. Aim of the study was to identify the relation between basic parameter of the FDM process – model orientation during manufacturing – and a dimensional accuracy and repeatability of obtained products. A set of samples was prepared – they were manufactured with variable process parameters and they were measured using 3D scanner. Significant differences in accuracy of products of the same geometry, but manufactured with different set of process parameters were observed.

  4. Effect of Nozzle Design and Processing Parameter on Characteristics of Glass/Polypropylene Hybrid Yarns

    Directory of Open Access Journals (Sweden)

    Dr Hireni Mankodi

    2014-12-01

    Full Text Available Among the various methods commingling process is comparatively better alternative to produce hybrid yarns. The required properties of hybrid yarns can be obtained by controlling main processing parameters such as air pressure, overfeed and take-up speed along with proper selection of nozzle (jet design. The commingling machine has been fabricated to study the commingling parameters. The nozzle is the most important element of the commingling machine. The design specification of commingling jet along with the processing parameters decides the final characteristics of yarn. In the present study two different types of jets have been selected to investigate commingling characteristics of glass/polypropylene hybrid yarn.

  5. Direct Slicing Based on Material Performance and Process Parameters for Selective Laser Sintering

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Direct slicing from CAD models to generate sectional contours of thepart to be sintered for Selective Laser Sintering (SLS) may overcome inherent disadvantages of using a Stereo Lithography ( STL ) format. In this paper, a direct slicing procedure is proposed for Selective Laser Sintering based on material performance and process parameters. Slicing thickness depends on the 3 D geometric model,material performance and process parameters. The relationship among material performance, process parameters and the largest slicing thickness is established using analysis of a sintering temperature field. A dynamic linked library is developed to realize direct slicing from a CAD model.

  6. Process Parameter Optimization for Wobbling Laser Spot Welding of Ti6Al4V Alloy

    Science.gov (United States)

    Vakili-Farahani, F.; Lungershausen, J.; Wasmer, K.

    Laser beam welding (LBW) coupled with "wobble effect" (fast oscillation of the laser beam) is very promising for high precision micro-joining industry. For this process, similarly to the conventional LBW, the laser welding process parameters play a very significant role in determining the quality of a weld joint. Consequently, four process parameters (laser power, wobble frequency, number of rotations within a single laser pulse and focused position) and 5 responses (penetration, width, heat affected zone (HAZ), area of the fusion zone, area of HAZ and hardness) were investigated for spot welding of Ti6Al4V alloy (grade 5) using a design of experiments (DoE) approach. This paper presents experimental results showing the effects of variating the considered most important process parameters on the spot weld quality of Ti6Al4V alloy. Semi-empirical mathematical models were developed to correlate laser welding parameters to each of the measured weld responses. Adequacies of the models were then examined by various methods such as ANOVA. These models not only allows a better understanding of the wobble laser welding process and predict the process performance but also determines optimal process parameters. Therefore, optimal combination of process parameters was determined considering certain quality criteria set.

  7. Short-time plasma surface modification of HDPE powder in a Plasma Downer Reactor - process, wettability improvement and ageing effects

    Energy Technology Data Exchange (ETDEWEB)

    Arpagaus, C. [ETH Swiss Federal Institute of Technology Zurich, Institute of Process Engineering, Department of Mechanical and Process Engineering, ETH Zentrum, Sonneggstrasse 3, CH-8092 Zurich (Switzerland); Rossi, A. [ETH Swiss Federal Institute of Technology Zurich, Laboratory for Surface Science and Technology, Department of Materials, ETH Hoenggerberg, Wolfgang-Pauli-Strasse 10, CH-8093 Zurich (Switzerland); Universita degli Studi di Cagliari, Dipartimento di Chimica Inorganica ed Analitica, UdR INSTM I-09100 Cagliari (Italy); Rudolf von Rohr, Ph. [ETH Swiss Federal Institute of Technology Zurich, Institute of Process Engineering, Department of Mechanical and Process Engineering, ETH Zentrum, Sonneggstrasse 3, CH-8092 Zurich (Switzerland)]. E-mail: vonrohr@ipe.mavt.ethz.ch

    2005-12-15

    The effectiveness of improving the wettability of HDPE powders within less than 0.1 s by plasma surface modification in a Plasma Downer Reactor is investigated. A correlation is revealed between the XPS results (O/C-ratio) and the wettability (contact angle, polar surface tension by capillary rise method). The O{sub 2}-content in the plasma feed gas has been adjusted for best wettability properties. XPS results indicate the formation of C=O and COOH functional groups on the powder surface. The O/C-ratio increased from 0.0 (no oxygen on the non-treated powder) up to 0.15 for the plasma treated HDPE powder surface. With pure O{sub 2}-plasma treatment, a water contact angle reduction from >90{sup o} (no water penetration into the untreated PE powder) down to 65{sup o} was achieved. The total surface free energy increased from 31.2 to 45 mN/m. Ageing of treated powders occurs and proceeds mostly within the first 7 days of storage. Contact angle measurements and O1s/O2s intensity ratio data support that ageing is mainly a diffusion-controlled process. Nevertheless, XPS results show the presence of oxygen functional groups even after 40 days, which explains why the powder is still dispersible in water without any addition of surfactants.

  8. Optimization of process parameters in drilling of fibre hybrid composite using Taguchi and grey relational analysis

    Science.gov (United States)

    Vijaya Ramnath, B.; Sharavanan, S.; Jeykrishnan, J.

    2017-03-01

    Nowadays quality plays a vital role in all the products. Hence, the development in manufacturing process focuses on the fabrication of composite with high dimensional accuracy and also incurring low manufacturing cost. In this work, an investigation on machining parameters has been performed on jute-flax hybrid composite. Here, the two important responses characteristics like surface roughness and material removal rate are optimized by employing 3 machining input parameters. The input variables considered are drill bit diameter, spindle speed and feed rate. Machining is done on CNC vertical drilling machine at different levels of drilling parameters. Taguchi’s L16 orthogonal array is used for optimizing individual tool parameters. Analysis Of Variance is used to find the significance of individual parameters. The simultaneous optimization of the process parameters is done by grey relational analysis. The results of this investigation shows that, spindle speed and drill bit diameter have most effect on material removal rate and surface roughness followed by feed rate.

  9. Temperature of hydrogen radio frequency plasma under dechlorination process of polychlorinated biphenyls

    Science.gov (United States)

    Inada, Y.; Abe, K.; Kumada, A.; Hidaka, K.; Amano, K.; Itoh, K.; Oono, T.

    2014-10-01

    It has been reported that RF (radio frequency) hydrogen plasmas promote the dechlorination process of PCBs (polychlorinated biphenyls) under irradiation of MW (microwave). A relative emission intensity spectroscope system was used for single-shot imaging of two-dimensional temperature distributions of RF hydrogen plasmas generated in chemical solutions with several mixing ratios of isopropyl alcohol (IPA) and insulation oil under MW irradiation. Our experimental results showed that the plasma generation frequencies for the oil-contaminating solutions were higher than that for the pure IPA solution. In addition, the plasma temperature in the compound liquids including both oil and IPA was higher than that in the pure IPA and oil solutions. A combination of the plasma temperature measurements and plasma composition analysis indicated that the hydrogen radicals generated in a chemical solution containing the equal volumes of IPA and oil were almost the same amounts of H and H+, while those produced in the other solutions were mainly H.

  10. OPTIMIZATION OF OPERATING PARAMETERS FOR EDM PROCESS BASED ON THE TAGUCHI METHOD AND ARTIFICIAL NEURAL NETWORK

    Directory of Open Access Journals (Sweden)

    A.Thillaivanan,

    2010-12-01

    Full Text Available In this paper the complexity of electrical discharge machining process which is very difficult to determine optimal cutting parameters for improving cutting performance has been reported. Optimization of operating parameters is an important step in machining, particularly for operating unconventional machiningprocedure like EDM. A suitable selection of machining parameters for the electrical discharge machining process relies heavily on the operators’ technologies and experience because of their numerous and diverse range. Machining parameters tables provided by the machine tool builder can not meet the operators’ requirements, since for anarbitrary desired machining time for a particular job, they do not provide the optimal machining conditions. An approach to determine parameters setting is proposed. Based on the Taguchi parameter design method and the analysis of variance, the significant factors affecting the machining performance such as total machining time, oversize and taper for a hole machined by EDM process, are determined.Artificial neural networks are highly flexible modeling tools with an ability to learn the mapping between input variables and output feature spaces. The superiority of using artificial neural networks inmodeling machining processes make easier to model the EDM process with dimensional input and output spaces. On the basis of the developed neural network model, for a required total machining time, oversize and taper the corresponding process parameters to be set in EDM by using the developed and trained ANN are determined.

  11. Comparison between measured scrape-off layer plasma parameters and 2D model calculations for JET X-point discharges

    Energy Technology Data Exchange (ETDEWEB)

    Loarte, A. [JET Joint Undertaking, Abingdon, Oxon, OX14 3EA (United Kingdom); Chankin, A. [JET Joint Undertaking, Abingdon, Oxon, OX14 3EA (United Kingdom); Clement, S. [JET Joint Undertaking, Abingdon, Oxon, OX14 3EA (United Kingdom); Corrigan, G. [JET Joint Undertaking, Abingdon, Oxon, OX14 3EA (United Kingdom); Harbour, P. [JET Joint Undertaking, Abingdon, Oxon, OX14 3EA (United Kingdom); Horton, L. [JET Joint Undertaking, Abingdon, Oxon, OX14 3EA (United Kingdom); Janeschitz, G. [JET Joint Undertaking, Abingdon, Oxon, OX14 3EA (United Kingdom); Lingertat, J. [JET Joint Undertaking, Abingdon, Oxon, OX14 3EA (United Kingdom); Matthews, G. [JET Joint Undertaking, Abingdon, Oxon, OX14 3EA (United Kingdom); Simonini, R. [JET Joint Undertaking, Abingdon, Oxon, OX14 3EA (United Kingdom); Tagle, J.A. [JET Joint Undertaking, Abingdon, Oxon, OX14 3EA (United Kingdom); Taroni, A. [JET Joint Undertaking, Abingdon, Oxon, OX14 3EA (United Kingdom); Vlases, G. [JET Joint Undertaking, Abingdon, Oxon, OX14 3EA (United Kingdom)

    1995-04-01

    Modelling with the EDGE2D/U-NIMBUS code of the measured scrape-off layer plasma parameters for JET divertor discharges is presented. Model results agree with the experiment if very small values (< or {approx}0.1 m{sup 2}/s in H-modes and low power L-modes) for the anomalous particle transport diffusion coefficient in the SOL are used. While the assumption of the power flow out of the main plasma being carried equally by the electrons and the ions describes satisfactorily the global power balance for Ohmic and L-mode discharges, more power flowing out through the ion channel is consistent with the power balance in hot ion H-modes. Some sensitivity studies of the code results on the modelling hypothesis are discussed. ((orig.)).

  12. Effects of Processing Parameters on the Forming Quality of C-Shaped Thermosetting Composite Laminates in Hot Diaphragm Forming Process

    Science.gov (United States)

    Bian, X. X.; Gu, Y. Z.; Sun, J.; Li, M.; Liu, W. P.; Zhang, Z. G.

    2013-10-01

    In this study, the effects of processing temperature and vacuum applying rate on the forming quality of C-shaped carbon fiber reinforced epoxy resin matrix composite laminates during hot diaphragm forming process were investigated. C-shaped prepreg preforms were produced using a home-made hot diaphragm forming equipment. The thickness variations of the preforms and the manufacturing defects after diaphragm forming process, including fiber wrinkling and voids, were evaluated to understand the forming mechanism. Furthermore, both interlaminar slipping friction and compaction behavior of the prepreg stacks were experimentally analyzed for showing the importance of the processing parameters. In addition, autoclave processing was used to cure the C-shaped preforms to investigate the changes of the defects before and after cure process. The results show that the C-shaped prepreg preforms with good forming quality can be achieved through increasing processing temperature and reducing vacuum applying rate, which obviously promote prepreg interlaminar slipping process. The process temperature and forming rate in hot diaphragm forming process strongly influence prepreg interply frictional force, and the maximum interlaminar frictional force can be taken as a key parameter for processing parameter optimization. Autoclave process is effective in eliminating voids in the preforms and can alleviate fiber wrinkles to a certain extent.

  13. Plasma parameters and electromagnetic forces induced by the magneto hydro dynamic interaction in a hypersonic argon flow experiment

    Science.gov (United States)

    Cristofolini, Andrea; Neretti, Gabriele; Borghi, Carlo A.

    2012-08-01

    This work proposes an experimental analysis on the magneto hydro dynamic (MHD) interaction induced by a magnetic test body immersed into a hypersonic argon flow. The characteristic plasma parameters are measured. They are related to the voltages arising in the Hall direction and to the variation of the fluid dynamic properties induced by the interaction. The tests have been performed in a hypersonic wind tunnel at Mach 6 and Mach 15. The plasma parameters are measured in the stagnation region in front of the nozzle of the wind tunnel and in the free stream region at the nozzle exit. The test body has a conical shape with the cone axis in the gas flow direction and the cone vertex against the flow. It is placed at the nozzle exit and is equipped with three permanent magnets. In the configuration adopted, the Faraday current flows in a closed loop completely immersed into the plasma of the shock layer. The electric field and the pressure variation due to MHD interaction have been measured on the test body walls. Microwave adsorption measurements have been used for the determination of the electron number density and the electron collision frequency. Continuum recombination radiation and line radiation emissions have been detected. The electron temperature has been determined by means of the spectroscopic data by using different methods. The electron number density has been also determined by means of the Stark broadening of Hα and the Hβ lines. Optical imaging has been utilized to visualize the pattern of the electric current distribution in the shock layer around the test body. The experiments show a considerable effect of the electromagnetic forces produced by the MHD interaction acting on the plasma flow around the test body. A comparison of the experimental data with simulation results shows a good agreement.

  14. Parameters of the plasma of a dc pulsating discharge in a supersonic air flow

    Energy Technology Data Exchange (ETDEWEB)

    Shibkov, V. M., E-mail: shibkov@phys.msu.ru; Shibkova, L. V.; Logunov, A. A. [Moscow State University, Faculty of Physics (Russian Federation)

    2017-03-15

    A dc discharge in a cold (T = 200 K) supersonic air flow at a static pressure of 200–400 Torr was studied experimentally. The excited unsteady pulsating discharge has the form of a thin plasma channel with a diameter of ≤1 mm, stretched downstream the flow. Depending on the discharge current, the pulsation frequency varies from 800 to 1600 Hz and the electron temperature varies from 8000 to 15000 K.

  15. Plasma Oxytocin in Children with Autism and Its Correlations with Behavioral Parameters in Children and Parents

    OpenAIRE

    Husarova, Veronika Marcincakova; Lakatosova, Silvia; Pivovarciova, Anna; Babinska, Katarina; Bakos, Jan; Durdiakova, Jaroslava; Kubranska, Aneta; Ondrejka, Igor; Ostatnikova, Daniela

    2016-01-01

    Objective Oxytocin (OT) has been implicated to play an important role in autism spectrum disorders (ASD) etiology. We aimed to find out the differences in plasma OT levels between children with autism and healthy children, the associations of OT levels with particular autism symptoms and the associations of particular parental autistic traits with their ASD children OT levels. Methods We included 19 boys with autism and 44 healthy age-matched boys. OT levels were analyzed by ELISA method. Chi...

  16. A Study on the Influence of Process Parameters on the Viscoelastic Properties of ABS Components Manufactured by FDM Process

    Science.gov (United States)

    Dakshinamurthy, Devika; Gupta, Srinivasa

    2016-06-01

    Fused Deposition Modelling (FDM) is a fast growing Rapid Prototyping (RP) technology due to its ability to build parts having complex geometrical shape in reasonable time period. The quality of built parts depends on many process variables. In this study, the influence of three FDM process parameters namely, slice height, raster angle and raster width on viscoelastic properties of Acrylonitrile Butadiene Styrene (ABS) RP-specimen is studied. Statistically designed experiments have been conducted for finding the optimum process parameter setting for enhancing the storage modulus. Dynamic Mechanical Analysis has been used to understand the viscoelastic properties at various parameter settings. At the optimal parameter setting the storage modulus and loss modulus of the ABS-RP specimen was 1008 and 259.9 MPa respectively. The relative percentage contribution of slice height and raster width on the viscoelastic properties of the FDM-RP components was found to be 55 and 31 % respectively.

  17. Determination of Stark parameters by cross-calibration in a multi-element laser-induced plasma

    Science.gov (United States)

    Liu, Hao; Truscott, Benjamin S.; Ashfold, Michael N. R.

    2016-05-01

    We illustrate a Stark broadening analysis of the electron density Ne and temperature Te in a laser-induced plasma (LIP), using a model free of assumptions regarding local thermodynamic equilibrium (LTE). The method relies on Stark parameters determined also without assuming LTE, which are often unknown and unavailable in the literature. Here, we demonstrate that the necessary values can be obtained in situ by cross-calibration between the spectral lines of different charge states, and even different elements, given determinations of Ne and Te based on appropriate parameters for at least one observed transition. This approach enables essentially free choice between species on which to base the analysis, extending the range over which these properties can be measured and giving improved access to low-density plasmas out of LTE. Because of the availability of suitable tabulated values for several charge states of both Si and C, the example of a SiC LIP is taken to illustrate the consistency and accuracy of the procedure. The cross-calibrated Stark parameters are at least as reliable as values obtained by other means, offering a straightforward route to extending the literature in this area.

  18. Plant parameters for plant functional groups of western rangelands to enable process-based simulation modeling

    Science.gov (United States)

    Regional environmental assessments with process-based models require realistic estimates of plant parameters for the primary plant functional groups in the region. “Functional group” in this context is an operational term, based on similarities in plant type and in plant parameter values. Likewise...

  19. Introduction to Plasma Physics

    Science.gov (United States)

    Gurnett, Donald A.; Bhattacharjee, Amitava

    2017-03-01

    Preface; 1. Introduction; 2. Characteristic parameters of a plasma; 3. Single particle motions; 4. Waves in a cold plasma; 5. Kinetic theory and the moment equations; 6. Magnetohydrodynamics; 7. MHD equilibria and stability; 8. Discontinuities and shock waves; 9. Electrostatic waves in a hot unmagnetized plasma; 10. Waves in a hot magnetized plasma; 11. Nonlinear effects; 12. Collisional processes; Appendix A. Symbols; Appendix B. Useful trigonometric identities; Appendix C. Vector differential operators; Appendix D. Vector calculus identities; Index.

  20. Feature profile evolution in plasma processing using on-wafer monitoring system

    CERN Document Server

    Samukawa, Seiji

    2014-01-01

    This book provides for the first time a good understanding of the etching profile technologies that do not disturb the plasma. Three types of sensors are introduced: on-wafer UV sensors, on-wafer charge-up sensors and on-wafer sheath-shape sensors in the plasma processing and prediction system of real etching profiles based on monitoring data. Readers are made familiar with these sensors, which can measure real plasma process surface conditions such as defect generations due to UV-irradiation, ion flight direction due to charge-up voltage in high-aspect ratio structures and ion sheath conditions at the plasma/surface interface. The plasma etching profile realistically predicted by a computer simulation based on output data from these sensors is described.