WorldWideScience

Sample records for thermal oxidation tester

  1. Thermally exfoliated graphite oxide

    Science.gov (United States)

    Prud'Homme, Robert K. (Inventor); Aksay, Ilhan A. (Inventor); Abdala, Ahmed (Inventor)

    2011-01-01

    A modified graphite oxide material contains a thermally exfoliated graphite oxide with a surface area of from about 300 sq m/g to 2600 sq m/g, wherein the thermally exfoliated graphite oxide displays no signature of the original graphite and/or graphite oxide, as determined by X-ray diffraction.

  2. Thermal and oxidation effects

    Energy Technology Data Exchange (ETDEWEB)

    Adamcova, J.; Kolaoikova, I. [Prague Univ., Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles (Czech Republic); Adamcova, J. [Czech Geological Survey, Geologicka 6, Prague (Czech Republic); Kaufhold, S.; Dohrmann, R. [BGR, Federal Institute for Geoscience and Natural Resources, Hannover (Germany); Dohrmann, R. [LBEG, State Authority for Mining, Energy, and Geology, Hannover (Germany); Craen, M. de; Van Geet, M.; Honty, M.; Wang, L.; Weetjens, E. [CK-CEN - Belgian Nuclear Research Centre - Environment, Healt and Safety Institute, Mol (Belgium); Van Geet, M. [ONDRAF/NIRAS - Belgian Agency for Radioactive Waste and Enriched Fissile Materials, Brussel (Belgium); Pozzi, J.P.; Janots, D. [Ecole Normale Paris, CNRS Lab. de Geologie, 75 - Paris (France); Aubourg, C. [Universite Cergy Pontoise, CNRS Lab. de Tectonique, 95 (France); Cathelineau, M.; Rousset, D.; Ruck, R. [Nancy-1 Univ. Henri Poincare, CNRS G2R, 54 (France); Clauer, N. [Strasbourg-1 Univ., CNRS CGS, 67 (France); Liewig, N. [Institut Pluridisciplinaire Hubert Curien, CNRS, 67 - Strasbourg (France); Techer, I. [Nimes Univ., CNRS Cerege, 30 (France)

    2007-07-01

    This session gathers 4 articles dealing with: the alteration processes in bentonites: mineralogical and structural changes during long-term and short-term experiments (J. Adamcov, I. Kolarikova); the implications from the lot experiment regarding the selection of an optimum HLRW bentonite (S. Kaufhold, R. Dohrmann); the extent of oxidation in Boom clay as a result of excavation and ventilation of the HADES URF: Experimental and modelling assessments (M. De Craen, M. Van Geet, M. Honty, L. Wang, E. Weetjens); and the magnetic and mineralogical alterations under thermal stress at 95 deg. C of Callovo-Oxfordian clay-stones (Bure, France) and lower Dogger Mont Terri clay-stones, Switzerland (J.P. Pozzi, C. Aubourg, D. Janots, M. Cathelineau, N. Clauer, D. Rousset, R. Ruck, N. Liewig, I. Techer)

  3. Thermal expansion of beryllium oxide

    International Nuclear Information System (INIS)

    Solodukhin, A.V.; Kruzhalov, A.V.; Mazurenko, V.G.; Maslov, V.A.; Medvedev, V.A.; Polupanova, T.I.

    1987-01-01

    Precise measurements of temperature dependence of the coefficient of linear expansion in the 22-320 K temperature range on beryllium oxide monocrystals are conducted. A model of thermal expansion is suggested; the range of temperature dependence minimum of the coefficient of thermal expansion is well described within the frames of this model. The results of the experiment may be used for investigation of thermal stresses in crystals

  4. Poppet valve tester

    Science.gov (United States)

    Tellier, G. F.

    1973-01-01

    Tester investigates fundamental factors affecting cyclic life and sealing performance of valve seats and poppets. Tester provides for varying impact loading of poppet against seat and rate of cycling, and controls amount and type of relative motion between sealing faces of seat and poppet. Relative motion between seat and poppet can be varied in three modes.

  5. Comparative mutability of the Ames tester strains of Salmonella typhimurium by ultraviolet radiation and by 4-nitroquinoline I-oxide

    International Nuclear Information System (INIS)

    Nakano, E.; Ichikawa-Ryo, H.; Kondo, S.

    1982-01-01

    A standard method for determining mutant frequencies per survivor was used to study the detailed kinetics of reverse mutations of Ames tester strains of Salmonella typhimurium induced by UV and by 4NQO. After UV irradiation, strain TA1538 was non-mutable, but its plasmid-containing derivative TA98 was mutable, whereas TA1535 was mutable and its plasmid-bearing derivative TA100 was about 10-fold more mutable. After treatment with 4NQO, TA98 was less mutable than TA1538, whereas TA100 was more mutable than TA1535 by a factor of 10-50. TA1537 was slightly less mutable than TA1535 by either UV or 4NQO. The differential mutabilities of these strains are briefly discussed in relation to the 'hot spot' base sequences for reversion and the nature of DNA damage caused by UV and 4NQO. (orig.)

  6. UW VLSI chip tester

    Science.gov (United States)

    McKenzie, Neil

    1989-12-01

    We present a design for a low-cost, functional VLSI chip tester. It is based on the Apple MacIntosh II personal computer. It tests chips that have up to 128 pins. All pin drivers of the tester are bidirectional; each pin is programmed independently as an input or an output. The tester can test both static and dynamic chips. Rudimentary speed testing is provided. Chips are tested by executing C programs written by the user. A software library is provided for program development. Tests run under both the Mac Operating System and A/UX. The design is implemented using Xilinx Logic Cell Arrays. Price/performance tradeoffs are discussed.

  7. Separation medium containing thermally exfoliated graphite oxide

    Science.gov (United States)

    Prud'homme, Robert K. (Inventor); Aksay, Ilhan A. (Inventor); Herrera-Alonso, Margarita (Inventor)

    2012-01-01

    A separation medium, such as a chromatography filling or packing, containing a modified graphite oxide material, which is a thermally exfoliated graphite oxide with a surface area of from about 300 m.sup.2/g to 2600 m.sup.2/g, wherein the thermally exfoliated graphite oxide has a surface that has been at least partially functionalized.

  8. Common tester platform concept.

    Energy Technology Data Exchange (ETDEWEB)

    Hurst, Michael James

    2008-05-01

    This report summarizes the results of a case study on the doctrine of a common tester platform, a concept of a standardized platform that can be applicable across the broad spectrum of testing requirements throughout the various stages of a weapons program, as well as across the various weapons programs. The common tester concept strives to define an affordable, next-generation design that will meet testing requirements with the flexibility to grow and expand; supporting the initial development stages of a weapons program through to the final production and surveillance stages. This report discusses a concept investing key leveraging technologies and operational concepts combined with prototype tester-development experiences and practical lessons learned gleaned from past weapons programs.

  9. Thermal Oxidation of Structured Silicon Dioxide

    DEFF Research Database (Denmark)

    Christiansen, Thomas Lehrmann; Hansen, Ole; Jensen, Jørgen Arendt

    2014-01-01

    The topography of thermally oxidized, structured silicon dioxide is investigated through simulations, atomic force microscopy, and a proposed analytical model. A 357 nm thick oxide is structured by removing regions of the oxide in a masked etch with either reactive ion etching or hydrofluoric acid....... Subsequent thermal oxidation is performed in both dry and wet ambients in the temperature range 950◦C to 1100◦C growing a 205 ± 12 nm thick oxide in the etched mask windows. Lifting of the original oxide near the edge of the mask in the range 6 nm to 37 nm is seen with increased lifting for increasing...

  10. Advanced TCA Backplane Tester

    CERN Document Server

    Oltean, Alexandra Dana

    2004-01-01

    At the beginning of 2003, the PICMG group adopted the AdvancedTCA (Advanced Telecom Computing Architecture) standard. The 10Gb/s backplane of the AdvancedTCA chassis is well specified in the standard but it remains however a high end product, which can be itself subject to printed circuit board manufacturing control problems that could greatly affect its quality control. In order to study the practical aspects of high speed Ethernet switching at 10Gb/s and to validate the signal integrity of the AdvancedTCA backplane, we developed a Backplane Tester. The tester system is able of running monitored PRBS traffic at 3.125Gb/s over every link on the AdvancedTCA backplane simultaneously and to monitor any possible connectivity failure immediately in terms of link and slot position inside the chassis. The present report presents the architectural hardware design, the control structure and software aspects of the AdvancedTCA Backplane Tester design.

  11. Multimodal Friction Ignition Tester

    Science.gov (United States)

    Davis, Eddie; Howard, Bill; Herald, Stephen

    2009-01-01

    The multimodal friction ignition tester (MFIT) is a testbed for experiments on the thermal and mechanical effects of friction on material specimens in pressurized, oxygen-rich atmospheres. In simplest terms, a test involves recording sensory data while rubbing two specimens against each other at a controlled normal force, with either a random stroke or a sinusoidal stroke having controlled amplitude and frequency. The term multimodal in the full name of the apparatus refers to a capability for imposing any combination of widely ranging values of the atmospheric pressure, atmospheric oxygen content, stroke length, stroke frequency, and normal force. The MFIT was designed especially for studying the tendency toward heating and combustion of nonmetallic composite materials and the fretting of metals subjected to dynamic (vibrational) friction forces in the presence of liquid oxygen or pressurized gaseous oxygen test conditions approximating conditions expected to be encountered in proposed composite material oxygen tanks aboard aircraft and spacecraft in flight. The MFIT includes a stainless-steel pressure vessel capable of retaining the required test atmosphere. Mounted atop the vessel is a pneumatic cylinder containing a piston for exerting the specified normal force between the two specimens. Through a shaft seal, the piston shaft extends downward into the vessel. One of the specimens is mounted on a block, denoted the pressure block, at the lower end of the piston shaft. This specimen is pressed down against the other specimen, which is mounted in a recess in another block, denoted the slip block, that can be moved horizontally but not vertically. The slip block is driven in reciprocating horizontal motion by an electrodynamic vibration exciter outside the pressure vessel. The armature of the electrodynamic exciter is connected to the slip block via a horizontal shaft that extends into the pressure vessel via a second shaft seal. The reciprocating horizontal

  12. Thermal oxidation for air toxics control

    International Nuclear Information System (INIS)

    Pennington, R.L.

    1991-01-01

    The Administration projects annual expenditures of $1.1 billion by 1995, increasing to $6.7 billion by 2005, in order to comply with the new Clean Air Act Title III hazardous air pollutant requirements. The Title III requirements include 189 hazardous air pollutants which must be reduced or eliminated by 2003. Twenty of the 189 listed pollutants account for approximately 75 percent of all hazardous air pollutant emissions. Ninety percent of these 20 pollutants can be effectively controlled through one or mote of the thermal oxidation technologies. This paper reports that the advantages and disadvantages of each thermal oxidation technology vary substantially and must be reviewed for each application in order to establish the most effective thermal oxidation solution. Effective thermal oxidation will meet MACT (maximum achievable control technology) emission standards

  13. Tire containing thermally exfoliated graphite oxide

    Science.gov (United States)

    Prud'homme, Robert K. (Inventor); Aksay, Ilhan A. (Inventor)

    2011-01-01

    A tire, tire lining or inner tube, containing a polymer composite, made of at least one rubber and/or at least one elastomer and a modified graphite oxide material, which is a thermally exfoliated graphite oxide with a surface area of from about 300 sq m/g to 2600 sq m/g.

  14. Thermal oxidation of silicon with two oxidizing species

    International Nuclear Information System (INIS)

    Vild-Maior, A.A.; Filimon, S.

    1979-01-01

    A theoretical model for the thermal oxidation of silicon in wet oxygen is presented. It is shown that the presence of oxygen in the oxidation furnace has an important effect when the water temperature is not too high (less than about 65 deg C). The model is in good agreement with the experimental data. (author)

  15. Advanced TCA BAckplane Tester

    CERN Document Server

    Oltean, Alexandra Dana; PGNet2005

    2005-01-01

    The “Advanced Telecom Computing Architecture” (AdvancedTCA) is a modular standard chassis based system designed to support the needs of carrier class telecommunication applications. It is defined by a set of industry standards under the direction of the PICMG group. One early deployment of the standard technology has been a 10 Gigabit Ethernet switch developed in the framework of the EU funded ESTA project. In order to study the practical aspects of high speed Ethernet switching at 10 Gigabit and above and to validate the signal integrity of the AdvancedTCA backplane, we developed a Backplane Tester. This system is able to run pseudo-random bit sequence (PRBS) traffic at 3.125 Gbps over every link on the AdvancedTCA backplane simultaneously, and to monitor any possible connectivity failure immediately in terms of the link and slot positions inside the chassis. In this paper, we describe the design and the practical architectural hardware and software aspects of the AdvancedTCA Backplane Tester. We also pr...

  16. Microcontroller based Integrated Circuit Tester

    OpenAIRE

    Yousif Taha Yousif Elamin; Abdelrasoul Jabar Alzubaidi

    2015-01-01

    The digital integrated circuit (IC) tester is implemented by using the ATmega32 microcontroller . The microcontroller processes the inputs and outputs and displays the results on a Liquid Crystal Display (LCD). The basic function of the digital IC tester is to test a digital IC for correct logical functioning as described in the truth table and/or function table. The designed model can test digital ICs having 14 pins. Since it is programmable, any number of ICs can be tested . Thi...

  17. Spring performance tester for miniature extension springs

    Science.gov (United States)

    Salzbrenner, Bradley; Boyce, Brad

    2017-05-16

    A spring performance tester and method of testing a spring are disclosed that has improved accuracy and precision over prior art spring testers. The tester can perform static and cyclic testing. The spring tester can provide validation for product acceptance as well as test for cyclic degradation of springs, such as the change in the spring rate and fatigue failure.

  18. Thermal oxidation of III-V compounds

    International Nuclear Information System (INIS)

    Monteiro, O.R.; Evans, J.W.

    1988-01-01

    The thermal oxidation of two important III-V compound semiconductor materials, namely GaAs and InP, has been studied between 300 and 600 0 C. In-situ TEM, cross-sectional TEM (XTEM) and SIMS analyses were used to characterize the reaction products. The first technique allows us to access the reactions at the very moment they are occurring. XTEM provides a clearer picture of the distribution of phases in the oxidized samples. SIMS gives us information on the dopant redistribution after oxidation as well as enrichment of group V element at the oxide semiconductor interface. Based on those results, the reaction products were characterized and reaction mechanisms proposed

  19. Oxidation and thermal behavior of Jatropha curcas biodiesel ...

    African Journals Online (AJOL)

    The thermal and oxidation behavior is also affected adversely by the container metal. The present paper is dealing with the study of oxidation and thermal behavior of JCB with respect to different metal contents. It was found that influence of metal was detrimental to thermal and oxidation stability. Even small concentrations ...

  20. Non-thermal Plasma and Oxidative Stress

    Science.gov (United States)

    Toyokuni, Shinya

    2015-09-01

    Thermal plasmas and lasers have been used in medicine to cut and ablate tissues and for coagulation. Non-equilibrium atmospheric pressure plasma (NEAPP; non-thermal plasma) is a recently developed, non-thermal technique with possible biomedical applications. Although NEAPP reportedly generates reactive oxygen/nitrogen species, electrons, positive ions, and ultraviolet radiation, few research projects have been conducted to merge this technique with conventional free radical biology. Recently, Prof. Masaru Hori's group (Plasma Nanotechnology Research Center, Nagoya University) developed a NEAPP device with high electron density. Here electron spin resonance revealed hydroxyl radicals as a major product. To merge non-thermal plasma biology with the preexisting free radical biology, we evaluated lipid peroxidation and DNA modifications in various in vitro and ex vivo experiments. Conjugated dienes increased after exposure to linoleic and alfa-linolenic acids. An increase in 2-thiobarbituric acid-reactive substances was also increased after exposure to phosphatidylcholine, liposomes or liver homogenate. Direct exposure to rat liver in medium produced immunohistochemical evidence of 4-hydroxy-2-nonenal- and acrolein-modified proteins. Exposure to plasmid DNA induced dose-dependent single/double strand breaks and increased the amounts of 8-hydroxy-2'-deoxyguanosine and cyclobutane pyrimidine dimers. These results indicate that oxidative biomolecular damage by NEAPP is dose-dependent and thus can be controlled in a site-specific manner. Simultaneous oxidative and UV-specific DNA damage may be useful in cancer treatment. Other recent advancements in the related studies of non-thermal plasma in Nagoya University Graduate School of Medicine will also be discussed.

  1. Hydrogen fracture toughness tester completion

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, Michael J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-09-30

    The Hydrogen Fracture Toughness Tester (HFTT) is a mechanical testing machine designed for conducting fracture mechanics tests on materials in high-pressure hydrogen gas. The tester is needed for evaluating the effects of hydrogen on the cracking properties of tritium reservoir materials. It consists of an Instron Model 8862 Electromechanical Test Frame; an Autoclave Engineering Pressure Vessel, an Electric Potential Drop Crack Length Measurement System, associated computer control and data acquisition systems, and a high-pressure hydrogen gas manifold and handling system.

  2. Penetration Tester's Open Source Toolkit

    CERN Document Server

    Faircloth, Jeremy

    2011-01-01

    Great commercial penetration testing tools can be very expensive and sometimes hard to use or of questionable accuracy. This book helps solve both of these problems. The open source, no-cost penetration testing tools presented do a great job and can be modified by the user for each situation. Many tools, even ones that cost thousands of dollars, do not come with any type of instruction on how and in which situations the penetration tester can best use them. Penetration Tester's Open Source Toolkit, Third Edition, expands upon existing instructions so that a professional can get the most accura

  3. Oxide growth and damage evolution in thermal barrier coatings

    NARCIS (Netherlands)

    Hille, T.S.; Turteltaub, S.R.; Suiker, A.S.J.

    2011-01-01

    Cracking in thermal barrier coatings (TBC) is triggered by the development of a thermally-grown oxide (TGO) layer that develops during thermal cycling from the oxidation of aluminum present in the bond coat (BC). In the present communication a numerical model is presented that describes the

  4. Thermal properties of graphite oxide, thermally reduced graphene and chemically reduced graphene

    Science.gov (United States)

    Jankovský, Ondřej; Sedmidubský, David; Lojka, Michal; Sofer, Zdeněk

    2017-07-01

    We compared thermal behavior and other properties of graphite oxide, thermally reduced graphene and chemically reduced graphene. Graphite was oxidized according to the Hofmann method using potassium chlorate as oxidizing agent in strongly acidic environment. In the next step, the formed graphite oxide was chemically or thermally reduced yielding graphene. The mechanism of thermal reduction was studied using STA-MS. Graphite oxide and both thermally and chemically reduced graphenes were analysed by SEM, EDS, elemental combustion analysis, XPS, Raman spectroscopy, XRD and BET. These findings will help for the large scale production of graphene with appropriate chemical composition.

  5. Development of the tyre tester

    CSIR Research Space (South Africa)

    Kuduntwane, P

    2012-10-01

    Full Text Available of the tyre tester P KUDUNTWANE1, DU PLESSIS2 AND PROF. S ELS3 1CSIR Defence, Peace, Safety and Security, PO Box 395, Pretoria, South Africa, 0001 2Department of Mechanical Engineering, Central University of Technology, Private Bag X20539, Bloemfontein...

  6. Preparation and investigations of thermal properties of copper oxide ...

    Indian Academy of Sciences (India)

    The effects of copper oxide, aluminium oxide and graphite on the thermal and structural properties of the organic ... solar energy, and heat regulation of electronics, biomedical ..... We gratefully acknowledge the financial support provided by.

  7. Oxidation phase growth diagram of vanadium oxides film fabricated by rapid thermal annealing

    Institute of Scientific and Technical Information of China (English)

    Tamura KOZO; Zheng-cao LI; Yu-quan WANG; Jie NI; Yin HU; Zheng-jun ZHANG

    2009-01-01

    Thermal evaporation deposited vanadium oxide films were annealed in air by rapid thermal annealing (RTP). By adjusting the annealing temperature and time, a series of vanadium oxide films with various oxidation phases and surface morphologies were fabricated, and an oxidation phase growth diagram was established. It was observed that different oxidation phases appear at a limited and continuous annealing condition range, and the morphologic changes are related to the oxidation process.

  8. Influence of creep and cyclic oxidation in thermal barrier coatings

    Energy Technology Data Exchange (ETDEWEB)

    Seiler, Philipp; Baeker, Martin; Roesler, Joachim [Technische Univ. Braunschweig (Germany). Inst. fuer Werkstoffe

    2012-01-15

    The lifetime of thermal barrier coating systems is limited by cracks close to the interfaces, causing delamination. To study the failure mechanisms, a simplified model system is analysed which consists of a bond-coat bulk material, a thermally grown oxide, and an yttria-stabilised zirconia topcoat. The stresses in the model system are calculated using a finite element model which covers the simulation of full thermal cycles, creep in all layers, and the anisotropic oxidation during dwelling. Creep in the oxide and the thermal barrier coating is varied with the use of different creep parameter sets. The influence of creep in the bondcoat is analysed by using two different bond-coat materials: fast creeping Fecralloy and slow creeping oxide dispersion strengthened MA956. It is shown that creep in the bondcoat influences the lifetime of the coatings. Furthermore, a fast creeping thermally grown oxide benefits the lifetime of the coating system. (orig.)

  9. Thermal Oxidation Resistance of Rare Earth-Containing Composite Elastomer

    Institute of Scientific and Technical Information of China (English)

    邱关明; 张明; 周兰香; 中北里志; 井上真一; 冈本弘

    2001-01-01

    The rare earth-containing composite elastomer was obtained by the reaction of vinyl pyridine-SBR (PSBR) latex with rare earth alkoxides, and its thermal oxidation resistance was studied. After aging test, it is found that its retention rate of mechanical properties is far higher than that of the control sample. The results of thermogravimetric analysis show that its thermal-decomposing temperature rises largely. The analysis of oxidation mechanisms indicates that the main reasons for thermal oxidation resistance are that rare earth elements are of the utility to discontinue autoxidation chain reaction and that the formed complex structure has steric hindrance effect on oxidation.

  10. Rapidly Adaptable Instrumentation Tester (RAIT)

    International Nuclear Information System (INIS)

    Vargo, Timothy D.

    1999-01-01

    Emerging technologies in the field of ''Test ampersand Measurement'' have recently enabled the development of the Rapidly Adaptable Instrumentation Tester (RAIT). Based on software developed with LabVIEW, the RAIT design enables quick reconfiguration to test and calibrate a wide variety of telemetry systems. The consequences of inadequate testing could be devastating if a telemetry system were to fail during an expensive flight mission. Supporting both open-bench testing as well as automated test sequences, the RAIT has significantly lowered total time required to test and calibrate a system. This has resulted in an overall lower per unit testing cost than has been achievable in the past

  11. Enhanced Master Controller Unit Tester

    Science.gov (United States)

    Benson, Patricia; Johnson, Yvette; Johnson, Brian; Williams, Philip; Burton, Geoffrey; McCoy, Anthony

    2007-01-01

    The Enhanced Master Controller Unit Tester (EMUT) software is a tool for development and testing of software for a master controller (MC) flight computer. The primary function of the EMUT software is to simulate interfaces between the MC computer and external analog and digital circuitry (including other computers) in a rack of equipment to be used in scientific experiments. The simulations span the range of nominal, off-nominal, and erroneous operational conditions, enabling the testing of MC software before all the equipment becomes available.

  12. Electronic properties of thermally formed thin iron oxide films

    International Nuclear Information System (INIS)

    Wielant, J.; Goossens, V.; Hausbrand, R.; Terryn, H.

    2007-01-01

    The oxide layer, present between an organic coating and the substrate, guarantees adhesion of the coating and plays a determinating role in the delamination rate of the organic coating. The purpose of this study is to compare the resistive and semiconducting properties of thermal oxides formed on steel in two different atmospheres at 250 deg. C: an oxygen rich atmosphere, air, and an oxygen deficient atmosphere, N 2 . In N 2 , a magnetite layer grows while in air a duplex oxide film forms composed by an inner magnetite layer and a thin outer hematite scale. The heat treatment for different amounts of time at high temperature was used as method to sample the thickness variation and change in electronic and semiconducting properties of the thermal oxide layers. Firstly, linear voltammetric measurements were performed to have a first insight in the electrochemical behavior of the thermal oxides in a borate buffer solution. Electrochemical impedance spectroscopy in the same buffer combined with the Mott-Schottky analysis were used to determine the semiconducting properties of the thermal oxides. By spectroscopic ellipsometry (SE) and atomic force microscopy (AFM), respectively, the thickness and roughness of the oxide layers were determined supporting the physical interpretation of the voltammetric and EIS data. These measurements clearly showed that oxide layers with different constitution, oxide resistance, flatband potential and doping concentration can be grown by changing the atmosphere

  13. Tester-assisted built in test

    Science.gov (United States)

    Guntheroth, Kurt

    It is noted that board makers invest considerable time and money writing extensive self-tests and that this investment can be multiplied by selecting ATE (automatic test equipment) that complements and extends the power of the self-test. The tester can diagnose boards in situations where a fault prevents the self-test from running. If the tester monitors such resources as processor, memory, and I/O, confidence in test results is improved. The tester can be used during development of the self-test and to turn on prototypes before the self-test is complete. The author argues that emulative functional testers outperform other types of ATE on boards with BIST (built-in self-test) and lists features of emulative functional testers that are most important to users of BIST.

  14. Automotive body panel containing thermally exfoliated graphite oxide

    Science.gov (United States)

    Prud'Homme, Robert K. (Inventor); Aksay, Ilhan A. (Inventor); Adamson, Douglas (Inventor); Abdala, Ahmed (Inventor)

    2011-01-01

    An automotive body panel containing a polymer composite formed of at least one polymer and a modified graphite oxide material, which is a thermally exfoliated graphite oxide with a surface area of from about 300 m.sup.2/g to 2600 m.sup.2/g.

  15. Synthesis and characterization of thermally oxidized ZnO films

    Indian Academy of Sciences (India)

    Administrator

    Synthesis and characterization of thermally oxidized ZnO films. A P RAMBU1,* and N IFTIMIE2 .... R. −. Δ. = = (1) where Ra is the sensor resistance in the air and Rg is the .... ple, Aida and coworkers (2006) reported that the total oxidation is ...

  16. Effects of Thermal Annealing Conditions on Cupric Oxide Thin Film

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyo Seon; Oh, Hee-bong; Ryu, Hyukhyun [Inje University, Gimhae (Korea, Republic of); Lee, Won-Jae [Dong-Eui University, Busan (Korea, Republic of)

    2015-07-15

    In this study, cupric oxide (CuO) thin films were grown on fluorine doped tin oxide(FTO) substrate by using spin coating method. We investigated the effects of thermal annealing temperature and thermal annealing duration on the morphological, structural, optical and photoelectrochemical properties of the CuO film. From the results, we could find that the morphologies, grain sizes, crystallinity and photoelectrochemical properties were dependent on the annealing conditions. As a result, the maximum photocurrent density of -1.47 mA/cm{sup 2} (vs. SCE) was obtained from the sample with the thermal annealing conditions of 500 ℃ and 40 min.

  17. Isotope Fuels Impact Tester (IFIT)

    International Nuclear Information System (INIS)

    Frantz, C.E.; Taylor, J.W.; Court, D.B.

    1975-07-01

    The Isotope Fuels Impact Tester (IFIT) is used for safely impacting 238 PuO 2 heat sources that have been heated to 2000 0 C. Impact velocities reach 300 m/s (1000 ft/s). A gas gun with a 178-mm (7-in.) bore is used to accelerate the heat source, which is heated by a furnace built into the projectile. Double containment of the impacted heat source is obtained by two vessels that are sealed directly to the gun muzzle. The impact occurs in the inner vessel, and parts of the projectile jam into and thereby close each vessel. The inner vessel, containing the impacted heat source, is removed from the gun and is placed inside a glovebox for disassembly and heat-source recovery. IFIT's modular structure makes it versatile and adaptable to many types of tests. Many applications have demonstrated its versatility and, more important, its capability for impacting 238 PuO 2 heat sources safely. An approximate theoretical relation is used to predict proper conditions for achieving desired impact velocities. Bore lubricants and projectile-seal design are also important for achieving proper impact velocities

  18. 24 CFR 125.107 - Testers.

    Science.gov (United States)

    2010-04-01

    ... perjury. (b) Testers must receive training or be experienced in testing procedures and techniques. (c...; (3) Have had any employment or other affiliation, within one year, with the person or organization to...

  19. Tester status report: April-June 1979

    Energy Technology Data Exchange (ETDEWEB)

    Draut, C.F.

    1979-08-31

    This report details tester status and activities in support of testing of timers, actuators, detonators, firing sets, transducers, isolators, and pyrospacers for the period of April through June 1979.

  20. Ultrathin Oxide Passivation Layer by Rapid Thermal Oxidation for the Silicon Heterojunction Solar Cell Applications

    OpenAIRE

    Lee, Youngseok; Oh, Woongkyo; Dao, Vinh Ai; Hussain, Shahzada Qamar; Yi, Junsin

    2012-01-01

    It is difficult to deposit extremely thin a-Si:H layer in heterojunction with intrinsic thin layer (HIT) solar cell due to thermal damage and tough process control. This study aims to understand oxide passivation mechanism of silicon surface using rapid thermal oxidation (RTO) process by examining surface effective lifetime and surface recombination velocity. The presence of thin insulating a-Si:H layer is the key to get high Voc by lowering the leakage current (I0) which improves the efficie...

  1. Structural evolution of tunneling oxide passivating contact upon thermal annealing.

    Science.gov (United States)

    Choi, Sungjin; Min, Kwan Hong; Jeong, Myeong Sang; Lee, Jeong In; Kang, Min Gu; Song, Hee-Eun; Kang, Yoonmook; Lee, Hae-Seok; Kim, Donghwan; Kim, Ka-Hyun

    2017-10-16

    We report on the structural evolution of tunneling oxide passivating contact (TOPCon) for high efficient solar cells upon thermal annealing. The evolution of doped hydrogenated amorphous silicon (a-Si:H) into polycrystalline-silicon (poly-Si) by thermal annealing was accompanied with significant structural changes. Annealing at 600 °C for one minute introduced an increase in the implied open circuit voltage (V oc ) due to the hydrogen motion, but the implied V oc decreased again at 600 °C for five minutes. At annealing temperature above 800 °C, a-Si:H crystallized and formed poly-Si and thickness of tunneling oxide slightly decreased. The thickness of the interface tunneling oxide gradually decreased and the pinholes are formed through the tunneling oxide at a higher annealing temperature up to 1000 °C, which introduced the deteriorated carrier selectivity of the TOPCon structure. Our results indicate a correlation between the structural evolution of the TOPCon passivating contact and its passivation property at different stages of structural transition from the a-Si:H to the poly-Si as well as changes in the thickness profile of the tunneling oxide upon thermal annealing. Our result suggests that there is an optimum thickness of the tunneling oxide for passivating electron contact, in a range between 1.2 to 1.5 nm.

  2. Thermal oxidation vitrification flue gas elimination system

    International Nuclear Information System (INIS)

    Kephart, W.; Angelo, F.; Clemens, M.

    1995-01-01

    With minor modifications to a Best Demonstrated Available Technology hazardous waste incinerator, it is possible to obtain combustion without potentially toxic emissions by using technology currently employed in similar applications throughout industry. Further, these same modifications will reduce waste handling over an extended operating envelope while minimizing energy consumption. Three by-products are produced: industrial grade carbon dioxide, nitrogen, and a final waste form that will exceed Toxicity Characteristics Leaching Procedures requirements and satisfy nuclear waste product consistency tests. The proposed system utilizes oxygen rather than air as an oxidant to reduce the quantities of total emissions, improve the efficiency of the oxidation reactions, and minimize the generation of toxic NO x emissions. Not only will less potentially hazardous constituents be generated; all toxic substances can be contained and the primary emission, carbon dioxide -- the leading ''greenhouse gas'' contributing to global warming -- will be converted to an industrial by-product needed to enhance the extraction of energy feedstocks from maturing wells. Clearly, the proposed configuration conforms to the provisions for Most Achievable Control Technology as defined and mandated for the private sector by the Clear Air Act Amendments of 1990 to be implemented in 1997 and still lacking definition

  3. Solid Waste Decontamination by Thermal Desorption and Catalytic Oxidation Methods

    Czech Academy of Sciences Publication Activity Database

    Šolcová, Olga; Topka, Pavel; Soukup, Karel; Jirátová, Květa; Váňová, H.; Kaštánek, František

    2014-01-01

    Roč. 68, č. 9 (2014), s. 1279-1282 ISSN 0366-6352 R&D Projects: GA MPO FR-TI1/059 Institutional support: RVO:67985858 Keywords : thermal desorption * catalytic oxidation * soil decontamination Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.468, year: 2014

  4. Thermal diffusivity and conductivity of thorium- uranium mixed oxides

    Science.gov (United States)

    Saoudi, M.; Staicu, D.; Mouris, J.; Bergeron, A.; Hamilton, H.; Naji, M.; Freis, D.; Cologna, M.

    2018-03-01

    Thorium-uranium oxide pellets with high densities were prepared at the Canadian Nuclear Laboratories (CNL) by co-milling, pressing, and sintering at 2023 K, with UO2 mass contents of 0, 1.5, 3, 8, 13, 30, 60 and 100%. At the Joint Research Centre, Karlsruhe (JRC-Karlsruhe), thorium-uranium oxide pellets were prepared using the spark plasma sintering (SPS) technique with 79 and 93 wt. % UO2. The thermal diffusivity of (Th1-xUx)O2 (0 ≤ x ≤ 1) was measured at CNL and at JRC-Karlsruhe using the laser flash technique. ThO2 and (Th,U)O2 with 1.5, 3, 8 and 13 wt. % UO2 were found to be semi-transparent to the infrared wavelength of the laser and were coated with graphite for the thermal diffusivity measurements. This semi-transparency decreased with the addition of UO2 and was lost at about 30 wt. % of UO2 in ThO2. The thermal conductivity was deduced using the measured density and literature data for the specific heat capacity. The thermal conductivity for ThO2 is significantly higher than for UO2. The thermal conductivity of (Th,U)O2 decreases rapidly with increasing UO2 content, and for UO2 contents of 60% and higher, the conductivity of the thorium-uranium oxide fuel is close to UO2. As the mass difference between the Th and U atoms is small, the thermal conductivity decrease is attributed to the phonon scattering enhanced by lattice strain due to the introduction of uranium in ThO2 lattice. The new results were compared to the data available in the literature and were evaluated using the classical phonon transport model for oxide systems.

  5. Thermal imaging of solid oxide fuel cell anode processes

    Energy Technology Data Exchange (ETDEWEB)

    Pomfret, Michael B.; Kidwell, David A.; Owrutsky, Jeffrey C. [Chemistry Division, U.S. Naval Research Laboratory, Washington, DC 20375 (United States); Steinhurst, Daniel A. [Nova Research Inc., Alexandria, VA 22308 (United States)

    2010-01-01

    A Si-charge-coupled device (CCD), camera-based, near-infrared imaging system is demonstrated on Ni/yttria-stabilized zirconia (YSZ) fragments and the anodes of working solid oxide fuel cells (SOFCs). NiO reduction to Ni by H{sub 2} and carbon deposition lead to the fragment cooling by 5 {+-} 2 C and 16 {+-} 1 C, respectively. When air is flowed over the fragments, the temperature rises 24 {+-} 1 C as carbon and Ni are oxidized. In an operational SOFC, the decrease in temperature with carbon deposition is only 4.0 {+-} 0.1 C as the process is moderated by the presence of oxides and water. Electrochemical oxidation of carbon deposits results in a {delta}T of +2.2 {+-} 0.2 C, demonstrating that electrochemical oxidation is less vigorous than atmospheric oxidation. While the high temperatures of SOFCs are challenging in many respects, they facilitate thermal imaging because their emission overlaps the spectral response of inexpensive Si-CCD cameras. Using Si-CCD cameras has advantages in terms of cost, resolution, and convenience compared to mid-infrared thermal cameras. High spatial ({proportional_to}0.1 mm) and temperature ({proportional_to}0.1 C) resolutions are achieved in this system. This approach provides a convenient and effective analytical technique for investigating the effects of anode chemistry in operating SOFCs. (author)

  6. Thermal imaging of solid oxide fuel cell anode processes

    Science.gov (United States)

    Pomfret, Michael B.; Steinhurst, Daniel A.; Kidwell, David A.; Owrutsky, Jeffrey C.

    A Si-charge-coupled device (CCD), camera-based, near-infrared imaging system is demonstrated on Ni/yttria-stabilized zirconia (YSZ) fragments and the anodes of working solid oxide fuel cells (SOFCs). NiO reduction to Ni by H 2 and carbon deposition lead to the fragment cooling by 5 ± 2 °C and 16 ± 1 °C, respectively. When air is flowed over the fragments, the temperature rises 24 ± 1 °C as carbon and Ni are oxidized. In an operational SOFC, the decrease in temperature with carbon deposition is only 4.0 ± 0.1 °C as the process is moderated by the presence of oxides and water. Electrochemical oxidation of carbon deposits results in a Δ T of +2.2 ± 0.2 °C, demonstrating that electrochemical oxidation is less vigorous than atmospheric oxidation. While the high temperatures of SOFCs are challenging in many respects, they facilitate thermal imaging because their emission overlaps the spectral response of inexpensive Si-CCD cameras. Using Si-CCD cameras has advantages in terms of cost, resolution, and convenience compared to mid-infrared thermal cameras. High spatial (∼0.1 mm) and temperature (∼0.1 °C) resolutions are achieved in this system. This approach provides a convenient and effective analytical technique for investigating the effects of anode chemistry in operating SOFCs.

  7. Role of high-temperature creep stress in thermally grown oxide growth of thermal barrier coatings

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, K.; Nakao, Y.; Seo, D.; Miura, H.; Shoji, T. [Tohoku Univ., Sendai (Japan)

    2008-07-01

    Thermally grown oxide (TGO) grows at the top / bond coating interface of the thermal barrier coating (TBC) in service. It is supposed that the failures of the TBC occur due to thermal stress and the decrease of adhesive strength caused by the TGO growth. Recently, large local stress has been found to change both the diffusion constant of oxygen through an existing oxide and the rate of chemical reaction at the oxide / oxidized material interface. Since high thermal stress occurs in the TBC, the volume expansion of the newly grown oxide, and centrifugal force, the growth rate of the TGO may change depending on not only temperature but also the stress. The aim of this study is to make clear the influence of stress on the growth rate of the TGO quantitatively. As a result, the thickness of the TGO clearly increases with increase of the amplitude of the applied stress and temperature. The increase rate of the TGO thickness is approximately 23% when the applied stress is increased from 0 to 205 MPa at 900 C, and approximately 29% when the stress is increased from 0 to 150 MPa at 950 C. (orig.)

  8. Detection of thermally grown oxides in thermal barrier coatings by nondestructive evaluation

    Science.gov (United States)

    Fahr, A.; Rogé, B.; Thornton, J.

    2006-03-01

    The thermal-barrier coatings (TBC) sprayed on hot-section components of aircraft turbine engines commonly consist of a partially stabilized zirconia top-coat and an intermediate bond-coat applied on the metallic substrate. The bond-coat is made of an aluminide alloy that at high engine temperatures forms thermally grown oxides (TGO). Although formation of a thin layer of aluminum oxide at the interface between the ceramic top-coat and the bond-coat has the beneficial effect of protecting the metallic substrate from hot gases, oxide formation at splat boundaries or pores within the bond-coat is a source of weakness. In this study, plasma-sprayed TBC specimens are manufactured from two types of bond-coat powders and exposed to elevated temperatures to form oxides at the ceramic-bond-coat boundary and within the bond-coat. The specimens are then tested using nondestructive evaluation (NDE) and destructive metallography and compared with the as-manufactured samples. The objective is to determine if NDE can identify the oxidation within the bond-coat and give indication of its severity. While ultrasonic testing can provide some indication of the degree of bond-coat oxidation, the eddy current (EC) technique clearly identifies severe oxide formation within the bond-coat. Imaging of the EC signals as the function of probe location provides information on the spatial variations in the degree of oxidation, and thereby identifies which components or areas are prone to premature damage.

  9. Comparative investigations of tablet crushing force testers

    DEFF Research Database (Denmark)

    Sonnergaard, Jørn; Jensen, C.G.; Poulsen, L.

    2005-01-01

    The performance of 16 tablet breaking force testers was evaluated in terms of accuracy, reproducibility and repeatability. Three tablet formulations with different plastic or brittle deformation mechanisms and with target breaking forces of 50, 100 and 150 N were tested. Statistically significant...... by the concept of components of variance was 5-7 % depending on the model tablet excipient. The standard deviation within testers (repeatability) was affected by the type of model formulation showing increasing variability with increasing brittleness of the compressed material. No specific effect of altering...

  10. Armstrong Laboratory Space Visual Function Tester Program

    Science.gov (United States)

    Oneal, Melvin R.; Task, H. Lee; Gleason, Gerald A.

    1992-01-01

    Viewgraphs on space visual function tester program are presented. Many astronauts and cosmonauts have commented on apparent changes in their vision while on-orbit. Comments have included descriptions of earth features and objects that would suggest enhanced distance visual acuity. In contrast, some cosmonaut observations suggest a slight loss in their object discrimination during initial space flight. Astronauts have also mentioned a decreased near vision capability that did not recover to normal until return to earth. Duntley space vision experiment, USSR space vision experiments, and visual function testers are described.

  11. Thermal gradient effects on the oxidation of Zircaloy fuel cladding

    International Nuclear Information System (INIS)

    Klein, A.C.; Reyes, J.N. Jr.; Maguire, M.A.

    1990-01-01

    A Thermal Gradient Test Facility (TGTF) has been designed and constructed to measure the thermal gradient effect on pressurized water reactor (PWR) fuel rod cladding. The TGTF includes a heat flux simulator assembly capable of producing a wide range of PWR operating conditions including water flow velocities and temperatures, water chemistry conditions, cladding temperatures, and heat fluxes ranging to 160 W/cm 2 . It is fully instrumented including a large number of thermocouples both inside the water flow channel and inside the cladding. Two test programs are in progress. First, cladding specimens are pre-oxidized in air at 500 deg. C and in 400 deg. C steam for various lengths of time to develop a range of uniform oxide thicknesses from 1 to 60 micrometers. The pre-oxidized specimens are placed in the TGTF to characterize the oxide thermal conductivity under a variety of water flow and heat flux conditions. Second, to overcome the long exposure times required under typical PWR conditions a series of tests with the addition of high concentrations of lithium hydroxide to the water are being considered. Static autoclave tests have been conducted with lithium hydroxide concentrations ranging from 0 to 2 moles per liter at 300, 330, and 360 deg. C for up to 36 hours. Results for zircaloy-4 show a considerable increase in the weight gain for the exposed samples with oxidation rate enhancement factors as high as 70 times that of pure water. Operation of the TGTF with elevated lithium hydroxide levels will yield real-time information concerning the effects of a heat flux on the oxidation kinetics of zircaloy fuel rod cladding. (author). 5 refs, 5 figs, 2 tabs

  12. Ultrasound assisted, thermally activated persulfate oxidation of coal tar DNAPLs.

    Science.gov (United States)

    Peng, Libin; Wang, Li; Hu, Xingting; Wu, Peihui; Wang, Xueqing; Huang, Chumei; Wang, Xiangyang; Deng, Dayi

    2016-11-15

    The feasibility of ultrasound assisted, thermally activated persulfate for effective oxidation of twenty 2-6 ringed coal tar PAHs in a biphasic tar/water system and a triphasic tar/soil/water system were investigated and established. The results indicate that ultrasonic assistance, persulfate and elevated reaction temperature are all required to achieve effective oxidation of coal tar PAHs, while the heating needed can be provided by ultrasonic induced heating as well. Further kinetic analysis reveals that the oxidation of individual PAH in the biphasic tar/water system follows the first-order kinetics, and individual PAH oxidation rate is primary determined by the mass transfer coefficients, tar/water interfacial areas, the aqueous solubility of individual PAH and its concentration in coal tar. Based on the kinetic analysis and experimental results, the contributions of ultrasound, persulfate and elevated reaction temperature to PAHs oxidation were characterized, and the effects of ultrasonic intensity and oxidant dosage on PAHs oxidation efficiency were investigated. In addition, the results indicate that individual PAH degradability is closely related to its reactivity as well, and the high reactivity of 4-6 ringed PAHs substantially improves their degradability. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Effect of thermal annealing of lead oxide film

    International Nuclear Information System (INIS)

    Hwang, Oh Hyeon; Kim, Sang Su; Suh, Jong Hee; Cho, Shin Hang; Kim, Ki Hyun; Hong, Jin Ki; Kim, Sun Ung

    2011-01-01

    Oxygen partial pressure in a growth process of lead oxide determines chemical and physical properties as well as crystalline structure. In order to supply oxygen, two ring-shape suppliers have been installed in a growth chamber. Films have been deposited using vacuum thermal evaporation from a raw material of yellow lead oxide powder (5N). Growth rate is controlled to be about 400 A/s, and film thickness more than 50 μm has been achieved. After deposition, the film is annealed at various temperatures under an oxygen atmosphere. In this study, an optimum growth condition for a good X-ray detector has been achieved by fine control of oxygen flow-rate and by thermal treatment. An electrical resistivity of 4.5x10 12 Ω cm is measured, and is comparable with the best data of PbO.

  14. Thermal neutron detectors based on complex oxide crystals

    CERN Document Server

    Ryzhikov, V; Volkov, V; Chernikov, V; Zelenskaya, O

    2002-01-01

    The ways of improvement of spectrometric quality of CWO and GSO crystals have been investigated with the aim of their application in thermal neutron detectors based on radiation capture reactions. The efficiency of the neutron detection by these crystals was measured, and the obtained data were compared with the results for sup 6 LiI(Tl) crystals. It is shown that the use of complex oxide crystals and neutron-absorption filters for spectrometry of thermal and resonance neutrons could be a promising method in combination with computer data processing. Numerical calculations are reported for spectra of gamma-quanta due to radiation capture of the neutrons. To compensate for the gamma-background lines, we used a crystal pair of heavy complex oxides with different sensitivity to neutrons.

  15. Studies of physicochemical properties of graphite oxide and thermally exfoliated/reduced graphene oxide

    Directory of Open Access Journals (Sweden)

    Drewniak Sabina Elżbieta

    2015-12-01

    Full Text Available The aim of the experimental research studies was to determine some electrical properties of graphite oxide and thermally exfoliated/reduced graphene oxide. The authors tried to interpret the obtained physicochemical results. For that purpose, both resistance measurements and investigation studies were carried out in order to characterize the samples. The resistance was measured at various temperatures in the course of composition changes of gas atmospheres (which surround the samples. The studies were also supported by such methods as: scanning electron microscopy (SEM, Raman spectroscopy (RS, atomic force microscopy (AFM and thermogravimetry (TG. Moreover, during the experiments also the elemental analyses (EA of the tested samples (graphite oxide and thermally exfoliated/reduced graphene oxide were performed.

  16. Ultrathin Oxide Passivation Layer by Rapid Thermal Oxidation for the Silicon Heterojunction Solar Cell Applications

    Directory of Open Access Journals (Sweden)

    Youngseok Lee

    2012-01-01

    Full Text Available It is difficult to deposit extremely thin a-Si:H layer in heterojunction with intrinsic thin layer (HIT solar cell due to thermal damage and tough process control. This study aims to understand oxide passivation mechanism of silicon surface using rapid thermal oxidation (RTO process by examining surface effective lifetime and surface recombination velocity. The presence of thin insulating a-Si:H layer is the key to get high Voc by lowering the leakage current (I0 which improves the efficiency of HIT solar cell. The ultrathin thermal passivation silicon oxide (SiO2 layer was deposited by RTO system in the temperature range 500–950°C for 2 to 6 minutes. The thickness of the silicon oxide layer was affected by RTO annealing temperature and treatment time. The best value of surface recombination velocity was recorded for the sample treated at a temperature of 850°C for 6 minutes at O2 flow rate of 3 Lpm. A surface recombination velocity below 25 cm/s was obtained for the silicon oxide layer of 4 nm thickness. This ultrathin SiO2 layer was employed for the fabrication of HIT solar cell structure instead of a-Si:H, (i layer and the passivation and tunneling effects of the silicon oxide layer were exploited. The photocurrent was decreased with the increase of illumination intensity and SiO2 thickness.

  17. 21 CFR 870.3720 - Pacemaker electrode function tester.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pacemaker electrode function tester. 870.3720... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3720 Pacemaker electrode function tester. (a) Identification. A pacemaker electrode function tester is a device which is...

  18. Two ankle joint laxity testers: reliability and validity

    NARCIS (Netherlands)

    Kerkhoffs, Gino M. M. J.; Blankevoort, Leendert; Sierevelt, Inger N.; Corvelein, Ruby; Janssen, Guido H. W.; van Dijk, C. Niek

    2005-01-01

    Two test devices were manufactured to objectively measure ankle joint laxity: the dynamic anterior ankle tester (DAAT) and the quasi-static anterior ankle tester (QAAT). The primary aim was to analyse the reliability of both testers; The secondary aim was to assess validity in correlation with TELOS

  19. Microstructural evolution and growth kinetics of thermally grown oxides in plasma sprayed thermal barrier coatings

    Directory of Open Access Journals (Sweden)

    Xiaoju Liu

    2016-02-01

    Full Text Available The formation of thermally grown oxide (TGO during high temperature is a key factor to the degradation of thermal barrier coatings (TBCs applied on hot section components. In the present study both the CoNiCrAlY bond coat and ZrO2-8 wt.% Y2O3 (8YSZ ceramic coat of TBCs were prepared by air plasma spraying (APS. The composition and microstructure of TGO in TBCs were investigated using scanning electron microscopy (SEM, energy dispersive spectroscopy (EDS and X-ray diffraction (XRD analysis. The growth rate of TGO for TBC and pure BC were gained after isothermal oxidation at 1100 °C for various times. The results showed that as-sprayed bond coat consisted of β and γ/γ′phases, β phase reducesd as the oxidation time increased. The TGO comprised α-Al2O3 formed in the first 2 h. CoO, NiO, Cr2O3 and spinel oxides appeared after 20 h of oxidation. Contents of CoO and NiO reduced while that of Cr2O3 and spinel oxides increased in the later oxidation stage. The TGO eventually consisted of a sub-Al2O3 layer with columnar microstructure and the upper porous CS clusters. The TGO growth kinetics for two kinds of samples followed parabolic laws, with oxidation rate constant of 0.344 μm/h0.5 for TBCs and 0.354 μm/h0.5 for pure BCs.

  20. Dall-Null tester for spaceborne applications

    Science.gov (United States)

    Wingler, R. L.

    1984-12-01

    This is a study to design a self correcting primary mirror system for a space telescope. The design is centered around a Dall-Null tester (a Foucault knife-edge tester with compensating lens). An indepth study of the theory of the Foucault test from Foucault's original publications to current work is presented. Also short comings of the diffraction approach are shown. The findings of a simple experiment showed the way to the correct explanation as to the workings of the test. Based on this new explanation, a computer program to find the error in the surface of the mirror from the irradiance pattern provided by the Dall-Null tester was developed. The computer program with a sample run is included in the appendixes A and B. The basic design of an adaptive optic system for a spaceborne application is also presented in the paper. This design has the desired quality of being able to correct the mirror while the telescope is in use. The equations being independent of wavelength allows for the design to be applied to systems working outside of the visible spectrum as well as the systems working in the visible.

  1. Corrosive environment tester for filter media

    International Nuclear Information System (INIS)

    Petit, G.S.; Weber, C.W.; Keinberger, C.A.; Rivers, R.D.

    1977-02-01

    Two continuous dynamic systems have been designed and fabricated for testing filter media in humid, corrosive environments--one for fluorine or fluoride exposures, and the other for nitrogen dioxide exposures. The tester using fluorine or fluoride atmospheres was constructed of nickel and the one using nitrogen dioxide was fabricated of stainless steel. Other corrosive gases could be used with the appropriate choice of system. For example, chlorine or hydrogen chloride could be used in the system fabricated of nickel, and sulfur dioxides or ammonia could be used in the stainless steel testing apparatus. Each tester is comprised of four equivalent dynamic systems designed for diluting a corrosive reagent with dry air, then with humidified air to provide a humid-corrosive environment for filter media testing. Auxiliary equipment includes a water injection system, corrosive reagent supply systems, and an automatic pressure differential (ΔP) monitoring and recording system. The testers are relatively maintenance-free and have operated continuously for periods as long as 96 h without requiring any attention, during total exposures of materials exceeding 600 h

  2. Role of thermal analysis in uranium oxide fuel fabrication process

    International Nuclear Information System (INIS)

    Balaji Rao, Y.; Yadav, R.B.

    2006-01-01

    The present paper discusses the application of thermal analysis, particularly, differential thermal analysis (Dta) at various stages of fuel fabrication process. The useful role of Dta in knowing the decomposition pattern and calcination temperature of Adu along with de-nitration temperature is explained. The decomposition pattern depends upon the type of drying process adopted for wet ADU cake (ADU C). Also, the paper highlights the utility of DTA in determining the APS and SSA of UO 2+x and U 3 O 8 powders as an alternate technique. Further, the temperature difference (ΔT max ) between the two exothermic peaks obtained in UO 2+x powder oxidation is related to sintered density of UO 2 pellets. (author)

  3. Upgrading non-oxidized carbon nanotubes by thermally decomposed hydrazine

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Pen-Cheng, E-mail: wangpc@ess.nthu.edu.tw [Department of Engineering and System Science, National Tsing Hua University, 101 Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan (China); Graduate Program for Science and Technology of Synchrotron Light Source, National Tsing Hua University, 101 Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan (China); Liao, Yu-Chun [Department of Engineering and System Science, National Tsing Hua University, 101 Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan (China); Graduate Program for Science and Technology of Synchrotron Light Source, National Tsing Hua University, 101 Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan (China); National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan (China); Liu, Li-Hung [Department of Engineering and System Science, National Tsing Hua University, 101 Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan (China); Lai, Yu-Ling; Lin, Ying-Chang [National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan (China); Hsu, Yao-Jane [Graduate Program for Science and Technology of Synchrotron Light Source, National Tsing Hua University, 101 Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan (China); National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan (China)

    2014-06-01

    We found that the electrical properties of conductive thin films based on non-oxidized carbon nanotubes (CNTs) could be further improved when the CNTs consecutively underwent a mild hydrazine adsorption treatment and then a sufficiently effective thermal desorption treatment. We also found that, after several rounds of vapor-phase hydrazine treatments and baking treatments were applied to an inferior single-CNT field-effect transistor device, the device showed improvement in I{sub on}/I{sub off} ratio and reduction in the extent of gate-sweeping hysteresis. Our experimental results indicate that, even though hydrazine is a well-known reducing agent, the characteristics of our hydrazine-exposed CNT samples subject to certain treatment conditions could become more graphenic than graphanic, suggesting that the improvement in the electrical and electronic properties of CNT samples could be related to the transient bonding and chemical scavenging of thermally decomposed hydrazine on the surface of CNTs.

  4. Upgrading non-oxidized carbon nanotubes by thermally decomposed hydrazine

    Science.gov (United States)

    Wang, Pen-Cheng; Liao, Yu-Chun; Liu, Li-Hung; Lai, Yu-Ling; Lin, Ying-Chang; Hsu, Yao-Jane

    2014-06-01

    We found that the electrical properties of conductive thin films based on non-oxidized carbon nanotubes (CNTs) could be further improved when the CNTs consecutively underwent a mild hydrazine adsorption treatment and then a sufficiently effective thermal desorption treatment. We also found that, after several rounds of vapor-phase hydrazine treatments and baking treatments were applied to an inferior single-CNT field-effect transistor device, the device showed improvement in Ion/Ioff ratio and reduction in the extent of gate-sweeping hysteresis. Our experimental results indicate that, even though hydrazine is a well-known reducing agent, the characteristics of our hydrazine-exposed CNT samples subject to certain treatment conditions could become more graphenic than graphanic, suggesting that the improvement in the electrical and electronic properties of CNT samples could be related to the transient bonding and chemical scavenging of thermally decomposed hydrazine on the surface of CNTs.

  5. Zero and low coefficient of thermal expansion polycrystalline oxides

    International Nuclear Information System (INIS)

    Skaggs, S.R.

    1977-09-01

    Polycrystalline oxide systems with zero to low coefficient of thermal expansion (CTE) investigated by the author include hafnia-titania and hafnia. The CTE for 30 to 40 mol% TiO 2 in HfO 2 is less than or equal to 1 x 10 -6 / 0 C, while for other compositions in the range 25 to 60 mol% it is approximately 4 x 10 -6 / 0 C. An investigation of the CTE of 99.999% HfO 2 yielded a value of 4.6 x 10 -6 / 0 C from room temperature to 1000 0 C. Correlation with data on HfO 2 by other investigators shows a definite relationship between the CTE and the amount of ZrO 2 present. Data are listed for comparison of the CTE of several other polycrystalline oxides investigated by Holcombe at Oak Ridge

  6. Zero and low coefficient of thermal expansion polycrystalline oxides

    International Nuclear Information System (INIS)

    Skaggs, S.R.

    1977-01-01

    Polycrystalline oxide systems with zero to low coefficient of thermal expansion (CTE) investigated by the author include hafnia-titania and hafnia. The CTE for 30 to 40 mol percent TiO 2 in HfO 2 is less than or equal to 1 x 10 -6 / 0 C, while for other compositions in the range 25 to 60 mol percent approximately 4 x 10 -6 / 0 C. An investigation of the CTE of 99.999 percent HfO 2 yielded a value of 4.6 x 10 -6 / 0 C from room temperature to 1000 0 C. Correlation with data on HfO 2 by other investigators shows a definite relationship between the CTE and the amount of ZrO 2 present. Data are listed for comparison of the CTE of several other polycrystalline oxides investigated by Holcombe at Oak Ridge

  7. Studies on Thermal Oxidation Stability of Aviation Lubricating Oils

    Directory of Open Access Journals (Sweden)

    Wu Nan

    2017-01-01

    Full Text Available Simulating the operating condition of aviation engine via autoclave experiment of high temperature and pressure, we studied the physic-chemical property of poly-α-olefin base oil samples mixed with antioxidants of 2,6-di-tert-butyl-4-methylphenol and p,p’-diisooctyl diphenylamine at different temperature. The mechanism of degradation of PAO aviation lubricating oil was analyzed according to the oxidized products by modern analytical instruments. The results showed that the aviation lubricating oil produced a large number of low molecule compounds while increasing the temperature, and resulted in the viscosity decreasing and acid value increasing which indicated that the thermal oxidation of the oil sample underwent a radical process.

  8. SO2 oxidation catalyst model systems characterized by thermal methods

    DEFF Research Database (Denmark)

    Hatem, G; Eriksen, Kim Michael; Gaune-Escard, M

    2002-01-01

    The molten salts M2S2O7 and MHSO4, the binary molten salt Systems M2S2O7-MHSO4 and the molten salt-gas systems M2S2O7 V2O5 and M2S2O7-M2SO4 V2O5 (M = Na, K, Rb, Cs) in O-2, SO2 and At atmospheres have been investigated by thermal methods like calorimetry, Differential Enthalpic Analysis (DEA) and...... to the mechanism Of SO2 oxidation by V2O5 based industrial catalysts....

  9. Thermal deoxygenation of graphite oxide at low temperature

    International Nuclear Information System (INIS)

    Kampars, V; Legzdina, M

    2015-01-01

    Synthesis of graphene via the deoxygenation of the graphite oxide (GO) is a method for the large-scale production of this nanomaterial possessing exceptional mechanical, electrical and translucent properties. Graphite oxide sheet contains at least four different oxygen atoms connected to the Csp 3 and Csp 2 atoms of the sheet in the form of hydroxyl, epoxy, carboxyl or carbonyl groups. Some of these functional groups are located at the surface but others situated at the edges of the platelets. To obtain the graphene nanoplatelets or the few-layer graphene the oxygen functionalities must be removed. Exfoliation and deoxygenation can be accomplished by the use of chemical reductants or heat. Thermal deoxygenation as greener and simpler approach is more preferable over chemical reduction approach. Usually a considerable mass loss of GO observed upon heating at temperatures starting at 200 °C and is attributed to the deoxygenation process. In order to avoid the defects of the obtained graphene sheets it is very important to find the methods for lowering the deoxygenation temperature of GO. Herein, we have investigated the way treatment of the Hummer's synthesis product with acetone and methyl tert-butyl ether under ultrasonication in order to lower the thermal stability of the graphite oxide and its deoxygenation temperature. The obtained results indicate that treatment of the graphite oxide with solvents mentioned above substantially reduces the reduction and exfoliation temperature (130 °C) under ambient atmosphere. The investigation of the composition of evolved gases by hyphenated Pyr/GC/MS method at different experimental conditions under helium atmosphere shows that without the expected H 2 O, CO and CO 2 also sulphur dioxide and acetone has been released

  10. Comparison of radiation-induced and thermal oxidative aging of polyethylene in the presence of inhibitors

    International Nuclear Information System (INIS)

    Dalinkevich, A.A.; Piskarev, I.M.

    1996-01-01

    Thermal oxidative and radiation-induced oxidative aging of inhibited polyethylene of commercial brands with known properties was studied at 60, 80 and 140 deg C. Radiation-induced oxidative aging was carried out under X-ray radiation with E max = 25 keV at dose rates providing specimen oxidation in kinetic conditions. The value of activation energy of thermal oxidative destruction of inhibited polyethylene under natural conditions of its employment at 60-140 deg C (E a = 60 kJ/mol) was obtained by comparison of data for radiation-induced and thermal oxidative destruction

  11. Modeling of thermal expansion coefficient of perovskite oxide for solid oxide fuel cell cathode

    Science.gov (United States)

    Heydari, F.; Maghsoudipour, A.; Alizadeh, M.; Khakpour, Z.; Javaheri, M.

    2015-09-01

    Artificial intelligence models have the capacity to eliminate the need for expensive experimental investigation in various areas of manufacturing processes, including the material science. This study investigates the applicability of adaptive neuro-fuzzy inference system (ANFIS) approach for modeling the performance parameters of thermal expansion coefficient (TEC) of perovskite oxide for solid oxide fuel cell cathode. Oxides (Ln = La, Nd, Sm and M = Fe, Ni, Mn) have been prepared and characterized to study the influence of the different cations on TEC. Experimental results have shown TEC decreases favorably with substitution of Nd3+ and Mn3+ ions in the lattice. Structural parameters of compounds have been determined by X-ray diffraction, and field emission scanning electron microscopy has been used for the morphological study. Comparison results indicated that the ANFIS technique could be employed successfully in modeling thermal expansion coefficient of perovskite oxide for solid oxide fuel cell cathode, and considerable savings in terms of cost and time could be obtained by using ANFIS technique.

  12. Development of a second generation rolling contact fatigue tester

    Science.gov (United States)

    Deshmukh, Satyam U.

    Contact fatigue failure has been in research since the early twentieth century. The need for a second generation sliding-rolling contact fatigue tester was proposed by Gregory Dvorak and Dr. Marcellin Zahui. The first generation RCF tester was used for testing super finishing processes for gear surfaces. The second generation RCF tester was funded by the Advanced Engineering Materials lab of University of North Dakota. Verification of the second generation Rolling Contact Fatigue Tester will be discussed in this thesis including the design details, assembly and testing procedure and to discuss its different parameters. The tester will have the capability of testing hollow specimens using a bobbin eddy current testing probe. This tester will allow a wide range of experiments and is not built for one specific purpose. An eddy current device is used for detecting cracks. The loading force is applied using hydraulic cylinders and a hydraulic power unit. Before testing began, the machine was run for some time at full speed. A lot of minor problems were detected and fixed. Three specimens of AISI 8620 were tested in this tester. All tests gave results matching with some of the other well-known RCF testers. These tests were performed to evaluate mechanical limits of the tester and to evaluate the software performance of the tester.

  13. Thermal oxidative degradation of wood modified with aminophenylborates

    Directory of Open Access Journals (Sweden)

    Klyachenkova Olga

    2016-01-01

    Full Text Available Comparative thermal analysis in the presence of oxygen was carried out for samples of native pine wood and wood samples modified with aminophenylborates. Significant decrease in the amount of heat released during thermal decomposition of the modified samples was established, which is due to the increase of carbonaceous residues on the surface. Reduction of heat release during decomposition of the modified samples may be explained by the lower yield of combustible volatile products as well as by thin film of boron oxide, formed on the surface of the modified wood, that partially reflects heat flow. Produced upon the modifier decomposition water vapor and inert nitrogen oxides dilute gaseous mixture near the wood surface and isolate it from oxygen. This enhances fire-resistance of wood modified with mono- and diethanolamine(N→Bphenylborates. Hydroxyl group at the sixth carbon atom of the glucopyranose ring of cellulose participates in reactions of cellulose modification, which prevents formation of flammable levoglucosan and, consequently, improves the fire-resistance of the modified wood.

  14. Effects of pressure on thermal transport in plutonium oxide powder

    International Nuclear Information System (INIS)

    Bielenberg, Patricia; Prenger, F. Coyne; Veirs, Douglas Kirk; Jones, Jerry

    2004-01-01

    Radial temperature profiles in plutonium oxide (PuO 2 ) powder were measured in a cylindrical vessel over a pressure range of 0.055 to 334.4 kPa with two different fill gases, helium and argon. The fine PuO 2 powder provides a very uniform self-heating medium amenable to relatively simple mathematical descriptions. At low pressures ( 2 powder has small particle sizes (on the order of 1 to 10 μm), random particle shapes, and high porosity so a more general model was required for this system. The model correctly predicts the temperature profiles of the powder over the wide pressure range for both argon and helium as fill gases. The effective thermal conductivity of the powder bed exhibits a pressure dependence at higher pressures because the pore sizes in the interparticle contact area are relatively small (less than 1 μm) and the Knudsen number remains above the continuum limit at these conditions for both fill gases. Also, the effective thermal conductivity with argon as a fill gas is higher than expected at higher pressures because the solid pathways account for over 80% of the effective powder conductivity. The results obtained from this model help to bring insight to the thermal conductivity of very fine ceramic powders with different fill gases.

  15. Growth and thermal oxidation of Ru and ZrO2 thin films as oxidation protective layers

    NARCIS (Netherlands)

    Coloma Ribera, R.

    2017-01-01

    This thesis focuses on the study of physical and chemical processes occurring during growth and thermal oxidation of Ru and ZrO2 thin films. Acting as oxidation resistant capping materials to prevent oxidation of layers underneath, these films have several applications, i.e., in microelectronics

  16. Packaging material and flexible medical tubing containing thermally exfoliated graphite oxide

    Science.gov (United States)

    Prud'homme, Robert K. (Inventor); Aksay, Ilhan A. (Inventor)

    2011-01-01

    A packaging material or flexible medical tubing containing a modified graphite oxide material, which is a thermally exfoliated graphite oxide with a surface area of from about 300 m.sup.2/g to 2600 m.sup.2/g.

  17. Research on characteristics measurement of infrared defect tester

    Science.gov (United States)

    Zhang, Ke-jia; Zhang, Bi-feng; Xiong, Li-min; Zhou, Tao-geng; Zhang, Jun-chao; Meng, Hai-feng; Cai, Chuan; He, Ying-wei; Li, Xiao-hui; Wang, Chang-shi

    2017-10-01

    Based on a testing method of spatial frequency response(SFR), a setup for characteristics measurements of the infrared defect tester,which can also be called electroluminescence tester(EL tester), a machine examining defects of photovoltaic (PV) panel, was built. The influences of focusing plane adjustments and infrared light box arrangements on resolution measurement of EL tester in full field of view were analyzed. For different types of EL testers, portable and fixed, testing methods and procedures were presented. Especially, a novel testing method for portable EL was claimed, which could do the work well without reference background. Based on method claimed and setup built, the resolutions of different types of EL testers were obtained and stable results were achieved. This setup is portable designed to meet online measurements requirements of PV industry.

  18. Thermal neutron scattering cross sections of beryllium and magnesium oxides

    International Nuclear Information System (INIS)

    Al-Qasir, Iyad; Jisrawi, Najeh; Gillette, Victor; Qteish, Abdallah

    2016-01-01

    Highlights: • Neutron thermalization in BeO and MgO was studied using Ab initio lattice dynamics. • The BeO phonon density of states used to generate the current ENDF library has issues. • The BeO cross sections can provide a more accurate ENDF library than the current one. • For MgO an ENDF library is lacking: a new accurate one can be built from our results. • BeO is a better filter than MgO, especially when cooled down to 77 K. - Abstract: Alkaline-earth beryllium and magnesium oxides are fundamental materials in nuclear industry and thermal neutron scattering applications. The calculation of the thermal neutron scattering cross sections requires a detailed knowledge of the lattice dynamics of the scattering medium. The vibrational properties of BeO and MgO are studied using first-principles calculations within the frame work of the density functional perturbation theory. Excellent agreement between the calculated phonon dispersion relations and the experimental data have been obtained. The phonon densities of states are utilized to calculate the scattering laws using the incoherent approximation. For BeO, there are concerns about the accuracy of the phonon density of states used to generate the current ENDF/B-VII.1 libraries. These concerns are identified, and their influences on the scattering law and inelastic scattering cross section are analyzed. For MgO, no up to date thermal neutron scattering cross section ENDF library is available, and our results represent a potential one for use in different applications. Moreover, the BeO and MgO efficiencies as neutron filters at different temperatures are investigated. BeO is found to be a better filter than MgO, especially when cooled down, and cooling MgO below 77 K does not significantly improve the filter’s efficiency.

  19. Building instructions: a motorcar battery tester

    Energy Technology Data Exchange (ETDEWEB)

    Kunz, K

    1975-02-01

    The circuit diagram of a motor car battery tester is given, intended for dashboard mounting. The condition of the battery is indicated by means of a light-emitting diode, which may be off (below 11 V), red (11 to 12.5 V), green (12.5 to 14.8 V) or flashing red (voltage exceeding 14.8 V). The circuit uses two transistors and a single integrated circuit (four-way comparator). Details of the layout, assembly, and testing procedures are included.

  20. Small-Bolt Torque-Tension Tester

    Science.gov (United States)

    Posey, Alan J.

    2009-01-01

    The device described here measures the torque-tension relationship for fasteners as small as #0. The small-bolt tester consists of a plate of high-strength steel into which three miniature load cells are recessed. The depth of the recess is sized so that the three load cells can be shimmed, the optimum height depending upon the test hardware. The three miniature load cells are arranged in an equilateral triangular configuration with the test bolt aligned with the centroid of the three. This is a kinematic arrangement.

  1. Oxidation kinetics of Si and SiGe by dry rapid thermal oxidation, in-situ steam generation oxidation and dry furnace oxidation

    Science.gov (United States)

    Rozé, Fabien; Gourhant, Olivier; Blanquet, Elisabeth; Bertin, François; Juhel, Marc; Abbate, Francesco; Pribat, Clément; Duru, Romain

    2017-06-01

    The fabrication of ultrathin compressively strained SiGe-On-Insulator layers by the condensation technique is likely a key milestone towards low-power and high performances FD-SOI logic devices. However, the SiGe condensation technique still requires challenges to be solved for an optimized use in an industrial environment. SiGe oxidation kinetics, upon which the condensation technique is founded, has still not reached a consensus in spite of various studies which gave insights into the matter. This paper aims to bridge the gaps between these studies by covering various oxidation processes relevant to today's technological needs with a new and quantitative analysis methodology. We thus address oxidation kinetics of SiGe with three Ge concentrations (0%, 10%, and 30%) by means of dry rapid thermal oxidation, in-situ steam generation oxidation, and dry furnace oxidation. Oxide thicknesses in the 50 Å to 150 Å range grown with oxidation temperatures between 850 and 1100 °C were targeted. The present work shows first that for all investigated processes, oxidation follows a parabolic regime even for thin oxides, which indicates a diffusion-limited oxidation regime. We also observe that, for all investigated processes, the SiGe oxidation rate is systematically higher than that of Si. The amplitude of the variation of oxidation kinetics of SiGe with respect to Si is found to be strongly dependent on the process type. Second, a new quantitative analysis methodology of oxidation kinetics is introduced. This methodology allows us to highlight the dependence of oxidation kinetics on the Ge concentration at the oxidation interface, which is modulated by the pile-up mechanism. Our results show that the oxidation rate increases with the Ge concentration at the oxidation interface.

  2. Effect of the top coat on the phase transformation of thermally grown oxide in thermal barrier coatings

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, X. [Materials Science Centre, School of Materials, University of Manchester, Manchester M1 7HS (United Kingdom); Hashimoto, T. [Materials Science Centre, School of Materials, University of Manchester, Manchester M1 7HS (United Kingdom); Xiao, P. [Materials Science Centre, School of Materials, University of Manchester, Manchester M1 7HS (United Kingdom)]. E-mail: ping.xiao@manchester.ac.uk

    2006-12-15

    The phase transformation of the thermally grown oxide (TGO) formed on a Pt enriched {gamma} + {gamma}' bond coat in electron beam physical vapour deposited thermal barrier coatings (TBCs) was studied by photo-stimulaluminescence spectroscopy. The presence of the TBC retards the {theta} to {alpha} transformation of the TGO and leads to a higher oxidation rate. The reasons for these phenomena are discussed.

  3. Thermal stress analysis of sulfur deactivated solid oxide fuel cells

    Science.gov (United States)

    Zeng, Shumao; Parbey, Joseph; Yu, Guangsen; Xu, Min; Li, Tingshuai; Andersson, Martin

    2018-03-01

    Hydrogen sulfide in fuels can deactivate catalyst for solid oxide fuel cells, which has become one of the most critical challenges to stability. The reactions between sulfur and catalyst will cause phase changes, leading to increase in cell polarization and mechanical mismatch. A three-dimensional computational fluid dynamics (CFD) approach based on the finite element method (FEM) is thus used to investigate the polarization, temperature and thermal stress in a sulfur deactivated SOFC by coupling equations for gas-phase species, heat, momentum, ion and electron transport. The results indicate that sulfur in fuels can strongly affect the cell polarization and thermal stresses, which shows a sharp decrease in the vicinity of electrolyte when 10% nickel in the functional layer is poisoned, but they remain almost unchanged even when the poisoned Ni content was increased to 90%. This investigation is helpful to deeply understand the sulfur poisoning effects and also benefit the material design and optimization of electrode structure to enhance cell performance and lifetimes in various hydrocarbon fuels containing impurities.

  4. Thermal and radiation induced polymerisation of carbon sub-oxide

    International Nuclear Information System (INIS)

    Schmidt, Michel

    1964-03-01

    This research thesis addresses the study of the polymerisation of carbon sub-oxide (C 3 O 2 ) in gaseous phase. As this work is related to other researches dealing with the reactions of the graphite-CO 2 system which occur in graphite-moderated nuclear reactors, a first intention was to study the behaviour of C 3 O 2 when submitted to radiations. Preliminary tests showed that the most remarkable result of this action was the formation of a polymer. It was also noticed that the polymerisation of this gas was spontaneous however slower at room temperature. The research thus focused on this polymerisation, and on the formula of the obtained polymer. After some generalities, the author reports the preparation, purification and storage and conservation of the carbon sub-oxide. The next parts report the kinetic study of thermal polymerisation, the study of polymerisation under γ rays, the study of the obtained polymer by using visible, UV and infrared spectroscopy, electronic paramagnetic resonance, and semi-conductivity measurements [fr

  5. Evaluation of bearing configurations using the single bearing tester in liquid nitrogen

    Science.gov (United States)

    Jett, T.; Hall, P.; Thom, R.

    1991-01-01

    Various bearing configurations were tested using the Marshall Space Flight Center single bearing tester with LN2 as the cryogenic coolant. The baseline was one Rocketdyne phase one high pressure oxidizer turbopump (HPOTP) pump end 45-mm bore bearing. The bearing configurations that were tested included a Salox/M cage configuration, a silicon nitride ball configuration, an elongated cage configuration, and a Bray 601 grease configuration.

  6. 7 CFR 801.4 - Tolerances for dockage testers.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Tolerances for dockage testers. 801.4 Section 801.4 Agriculture Regulations of the Department of Agriculture (Continued) GRAIN INSPECTION, PACKERS AND STOCKYARD... FOR GRAIN INSPECTION EQUIPMENT § 801.4 Tolerances for dockage testers. The maintenance tolerances for...

  7. Oxidation and thermal shock behavior of thermal barrier coated 18/10CrNi alloy with coating modifications

    Energy Technology Data Exchange (ETDEWEB)

    Guergen, Selim [Vocational School of Transportation, Anadolu University, Eskisehir (Turkmenistan); Diltemiz, Seyid Fehmi [Turkish Air Force1st Air Supply and Maintenance Center Command, Eskisehir (Turkmenistan); Kushan, Melih Cemal [Dept. of Mechanical Engineering, Eskisehir Osmangazi University, Eskisehir (Turkmenistan)

    2017-01-15

    In this study, substrates of 18/10CrNi alloy plates were initially sprayed with a Ni-21Cr-10Al-1Y bond coat and then with an yttria stabilized zirconia top coat by plasma spraying. Subsequently, plasma-sprayed Thermal barrier coatings (TBCs) were treated with two different modification methods, namely, vacuum heat treatment and laser glazing. The effects of modifications on the oxidation and thermal shock behavior of the coatings were evaluated. The effect of coat thickness on the bond strength of the coats was also investigated. Results showed enhancement of the oxidation resistance and thermal shock resistance of TBCs following modifications. Although vacuum heat treatment and laser glazing exhibited comparable results as per oxidation resistance, the former generated the best improvement in the thermal shock resistance of the TBCs. Bond strength also decreased as coat thickness increased.

  8. Thin copper oxide films prepared by ion beam sputtering with subsequent thermal oxidation: Application in chemiresistors

    Energy Technology Data Exchange (ETDEWEB)

    Horak, P., E-mail: phorak@ujf.cas.cz [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, 250 68 Řež (Czech Republic); Bejsovec, V.; Vacik, J.; Lavrentiev, V. [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, 250 68 Řež (Czech Republic); Vrnata, M. [Department of Physics and Measurements, The University of Chemistry and Technology, Prague, Technická 5, 166 28 Prague 6 (Czech Republic); Kormunda, M. [Department of Physics, Jan Evangelista Purkyně University in Ústí nad Labem, České mládeže 8, 400 96 Ústí nad Labem (Czech Republic); Danis, S. [Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 5, 121 16 Prague 2 (Czech Republic)

    2016-12-15

    Highlights: • A rapid oxidation process of thin copper films. • Sheet resistance up to 10{sup 9} Ω/◊. • Mixed oxide phase at 200 °C with significant hydroxide presence. • Gas sensing response to 1000 ppm of hydrogen and methanol vapours. • Increased sensitivity with Pd and Au catalyst to hydrogen and methanol, respectively. - Abstract: Copper oxide films were prepared by thermal oxidation of thin Cu films deposited on substrates by ion beam sputtering. The subsequent oxidation was achieved in the temperature range of 200 °C–600 °C with time of treatment from 1 to 7 h (with a 1-h step) in a furnace open to air. At temperatures 250 °C–600 °C, the dominant phase formed was CuO, while at 200 °C mainly the Cu{sub 2}O phase was identified. However, the oxidation at 200 °C led to a more complicated composition − in the depth Cu{sub 2}O phase was observed, though in the near-surface layer the CuO dominant phase was found with a significant presence of Cu(OH){sub 2}. A limited amount of Cu{sub 2}O was also found in samples annealed at 600 °C. The sheet resistance R{sub S} of the as-deposited Cu sample was 2.22 Ω/□, after gradual annealing R{sub S} was measured in the range 2.64 MΩ/□–2.45 GΩ/□. The highest R{sub S} values were obtained after annealing at 300 °C and 350 °C, respectively. Oxygen depth distribution was studied using the {sup 16}O(α,α) nuclear reaction with the resonance at energy 3032 keV. It was confirmed that the higher oxidation degree of copper is located in the near-surface region. Preliminary tests of the copper oxide films as an active layer of a chemiresistor were also performed. Hydrogen and methanol vapours, with a concentration of 1000 ppm, were detected by the sensor at an operating temperature of 300 °C and 350 °C, respectively. The response of the sensors, pointed at the p-type conductivity, was improved by the addition of thin Pd or Au catalytic films to the oxidic film surface. Pd-covered films showed

  9. Development of a Portable Torque Wrench Tester

    Science.gov (United States)

    Wang, Y.; Zhang, Q.; Gou, C.; Su, D.

    2018-03-01

    A portable torque wrench tester (PTWT) with calibration range from 0.5 Nm to 60 Nm has been developed and evaluated for periodic or on-site calibration of setting type torque wrenches, indicating type torque wrenches and hand torque screwdrivers. The PTWT is easy to carry with weight about 10 kg, simple and efficient operation and energy saving with an automatic loading and calibrating system. The relative expanded uncertainty of torque realized by the PTWT was estimated to be 0.8%, with the coverage factor k=2. A comparison experiment has been done between the PTWT and a reference torque standard at our laboratory. The consistency between these two devices under the claimed uncertainties was verified.

  10. Alternative method for steam generation for thermal oxidation of silicon

    Science.gov (United States)

    Spiegelman, Jeffrey J.

    2010-02-01

    Thermal oxidation of silicon is an important process step in MEMS device fabrication. Thicker oxide layers are often used as structural components and can take days or weeks to grow, causing high gas costs, maintenance issues, and a process bottleneck. Pyrolytic steam, which is generated from hydrogen and oxygen combustion, was the default process, but has serious drawbacks: cost, safety, particles, permitting, reduced growth rate, rapid hydrogen consumption, component breakdown and limited steam flow rates. Results from data collected over a 24 month period by a MEMS manufacturer supports replacement of pyrolytic torches with RASIRC Steamer technology to reduce process cycle time and enable expansion previously limited by local hydrogen permitting. Data was gathered to determine whether Steamers can meet or exceed pyrolytic torch performance. The RASIRC Steamer uses de-ionized water as its steam source, eliminating dependence on hydrogen and oxygen. A non-porous hydrophilic membrane selectively allows water vapor to pass. All other molecules are greatly restricted, so contaminants in water such as dissolved gases, ions, total organic compounds (TOC), particles, and metals can be removed in the steam phase. The MEMS manufacturer improved growth rate by 7% over the growth range from 1μm to 3.5μm. Over a four month period, wafer uniformity, refractive index, wafer stress, and etch rate were tracked with no significant difference found. The elimination of hydrogen generated a four-month return on investment (ROI). Mean time between failure (MTBF) was increased from 3 weeks to 32 weeks based on three Steamers operating over eight months.

  11. Oxidative reduction of glove box wipers with a downdraft thermal oxidation system

    International Nuclear Information System (INIS)

    Phelps, M.R.; Wilcox, W.A.

    1996-04-01

    Wipers (rags) used for decontamination and glove box cleanup in the Plutonium Finishing Plant often become soaked with acid and plutonium-rich solutions. After use, these wipers are rinsed in a dilute NaOH solution and dried, but the formation of unstable nitrates and the hydrogen gas caused by hydrolysis are concerns that still must be addressed. This report gives the results of testing with a small downdraft thermal oxidation system that was constructed by Pacific Northwest National Laboratory to stabilize glove wiper waste, reduce the waste volume, and reclaim plutonium. Proof-of-principle testing was conducted with eight runs using various combinations of rag moisture and chemical pretreatment. All runs went to planned completion. Results of these tests indicate that the thermal oxidation system has the potential for providing significant reductions in waste volume. Weight reductions of 150:1 were easily obtainable during this project. Modifications could result in weight reductions of over 200:1, with possible volume reductions of 500:1

  12. Surface and sub-surface thermal oxidation of thin ruthenium films

    Energy Technology Data Exchange (ETDEWEB)

    Coloma Ribera, R.; Kruijs, R. W. E. van de; Yakshin, A. E.; Bijkerk, F. [MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands); Kokke, S.; Zoethout, E. [FOM Dutch Institute for Fundamental Energy Research (DIFFER), P.O. Box 1207, 3430 BE Nieuwegein (Netherlands)

    2014-09-29

    A mixed 2D (film) and 3D (nano-column) growth of ruthenium oxide has been experimentally observed for thermally oxidized polycrystalline ruthenium thin films. Furthermore, in situ x-ray reflectivity upon annealing allowed the detection of 2D film growth as two separate layers consisting of low density and high density oxides. Nano-columns grow at the surface of the low density oxide layer, with the growth rate being limited by diffusion of ruthenium through the formed oxide film. Simultaneously, with the growth of the columns, sub-surface high density oxide continues to grow limited by diffusion of oxygen or ruthenium through the oxide film.

  13. Control of nitrogen oxides at thermal power plants

    Energy Technology Data Exchange (ETDEWEB)

    Kotler, V.R.; Hall, R.E.

    1991-01-01

    Reviews reports presented at the International symposium on reduction of NO{sub x} emissions from stationary pollutant sources, held in San Francisco (USA) in March 1989. Topics concentrated on the latest trends in power engineering in the USA and Europe. Reports were dedicated to test results of pilot plant equipment employing the increasingly popular LNB, OFA, Reburn, SNCR, and SCR technologies. The following conclusions are drawn on the basis of the symposium proceedings: The nitric oxide problem may be considered exaggerated in regard to thermal power plants because of errors made during flue gas composition analysis. The combination of new combustion chambers and staged air input with simultaneous redesigning of equipment is most widely employed in the USA (achieving a 50% NO{sub x} reduction with minimum effect on power plant operation and maintenance costs). Economic sense demands that primary methods of NO{sub x} removal be used prior to SCR implementation. The SCR technology reducing NO{sub x} emission by 60-80% with ammonia to less than 5 ppm is the most popular flue gas denitrification method. 15 refs.

  14. Thin copper oxide films prepared by ion beam sputtering with subsequent thermal oxidation: Application in chemiresistors

    Science.gov (United States)

    Horak, P.; Bejsovec, V.; Vacik, J.; Lavrentiev, V.; Vrnata, M.; Kormunda, M.; Danis, S.

    2016-12-01

    Copper oxide films were prepared by thermal oxidation of thin Cu films deposited on substrates by ion beam sputtering. The subsequent oxidation was achieved in the temperature range of 200 °C-600 °C with time of treatment from 1 to 7 h (with a 1-h step) in a furnace open to air. At temperatures 250 °C-600 °C, the dominant phase formed was CuO, while at 200 °C mainly the Cu2O phase was identified. However, the oxidation at 200 °C led to a more complicated composition - in the depth Cu2O phase was observed, though in the near-surface layer the CuO dominant phase was found with a significant presence of Cu(OH)2. A limited amount of Cu2O was also found in samples annealed at 600 °C. The sheet resistance RS of the as-deposited Cu sample was 2.22 Ω/□, after gradual annealing RS was measured in the range 2.64 MΩ/□-2.45 GΩ/□. The highest RS values were obtained after annealing at 300 °C and 350 °C, respectively. Oxygen depth distribution was studied using the 16O(α,α) nuclear reaction with the resonance at energy 3032 keV. It was confirmed that the higher oxidation degree of copper is located in the near-surface region. Preliminary tests of the copper oxide films as an active layer of a chemiresistor were also performed. Hydrogen and methanol vapours, with a concentration of 1000 ppm, were detected by the sensor at an operating temperature of 300 °C and 350 °C, respectively. The response of the sensors, pointed at the p-type conductivity, was improved by the addition of thin Pd or Au catalytic films to the oxidic film surface. Pd-covered films showed an increased response to hydrogen at 300 °C, while Au-covered films were more sensitive to methanol vapours at 350 °C.

  15. Effect of thermal treatment conditions on properties of vanadium molybdenum oxide catalyst in acrolein oxidation reaction to acrylic acid

    International Nuclear Information System (INIS)

    Gorshkova, T.P.; Tarasova, D.V.; Olen'kova, I.P.; Andrushkevich, T.V.; Nikoro, T.A.

    1984-01-01

    The effect of thermal treatment conditions (temperature and gas medium) on properties of vanadium molybdenum oxide catalyst in acrolein oxidation reaction to acrylic acid is investigated. It is shown that active and selective catalysts are formed in the course of thermal decomposition of the drying product of ammonium metavanadate and paramolybdate under the conditions ensuring the vanadium ion reduction up to tetravalent state with conservation of molybdenum oxidation degree equal to 6. It is possible to realize it either by treatment of the catalyst calcinated in the air flow at 300 deg by the reaction mixture at the activation stage or by gas-reducer flow treatment at 280 deg. Thermal treatment in the reducing medium of the oxidized catalyst does not lead to complete regeneration of its properties

  16. Thermal-treatment effect on the photoluminescence and gas-sensing properties of tungsten oxide nanowires

    International Nuclear Information System (INIS)

    Sun, Shibin; Chang, Xueting; Li, Zhenjiang

    2010-01-01

    Single-crystalline non-stoichiometric tungsten oxide nanowires were initially prepared using a simple solvothermal method. High resolution transmission electron microscopy (HRTEM) investigations indicate that the tungsten oxide nanowires exhibit various crystal defects, including stacking faults, dislocations, and vacancies. A possible defect-induced mechanism was proposed to account for the temperature-dependent morphological evolution of the tungsten oxide nanowires under thermal processing. Due to the high specific surface areas and non-stoichiometric crystal structure, the original tungsten oxide nanowires were highly sensitive to ppm level ethanol at room temperature. Thermal treatment under dry air condition was found to deteriorate the selectivity of room-temperature tungsten oxide sensors, and 400 o C may be considered as the top temperature limit in sensor applications for the solvothermally-prepared nanowires. The photoluminescence (PL) characteristics of tungsten oxide nanowires were also strongly influenced by thermal treatment.

  17. Thermal-treatment effect on the photoluminescence and gas-sensing properties of tungsten oxide nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Shibin [College of Electromechanical Engineering, Qingdao University of Science and Technology, Qingdao 266061, Shandong (China); Chang, Xueting [Institute of Materials Science and Engineering, Ocean University of China, Qingdao 266100, Shandong (China); Li, Zhenjiang, E-mail: zjli126@126.com [College of Electromechanical Engineering, Qingdao University of Science and Technology, Qingdao 266061, Shandong (China)

    2010-09-15

    Single-crystalline non-stoichiometric tungsten oxide nanowires were initially prepared using a simple solvothermal method. High resolution transmission electron microscopy (HRTEM) investigations indicate that the tungsten oxide nanowires exhibit various crystal defects, including stacking faults, dislocations, and vacancies. A possible defect-induced mechanism was proposed to account for the temperature-dependent morphological evolution of the tungsten oxide nanowires under thermal processing. Due to the high specific surface areas and non-stoichiometric crystal structure, the original tungsten oxide nanowires were highly sensitive to ppm level ethanol at room temperature. Thermal treatment under dry air condition was found to deteriorate the selectivity of room-temperature tungsten oxide sensors, and 400 {sup o}C may be considered as the top temperature limit in sensor applications for the solvothermally-prepared nanowires. The photoluminescence (PL) characteristics of tungsten oxide nanowires were also strongly influenced by thermal treatment.

  18. Improved the Surface Roughness of Silicon Nanophotonic Devices by Thermal Oxidation Method

    Energy Technology Data Exchange (ETDEWEB)

    Shi Zujun; Shao Shiqian; Wang Yi, E-mail: ywangwnlo@mail.hust.edu.cn [Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, No. 1037, Luoyu Street, Wuhan 430074 (China)

    2011-02-01

    The transmission loss of the silicon-on-insulator (SOI) waveguide and the coupling loss of the SOI grating are determined to a large extent by the surface roughness. In order to obtain smaller loss, thermal oxidation is a good choice to reduce the surface roughness of the SOI waveguide and grating. Before the thermal oxidation, the root mean square of the surface roughness is over 11 nm. After the thermal oxidation, the SEM figure shows that the bottom of the grating is as smooth as quartz surface, while the AFM shows that the root mean square of the surface is less than 5 nm.

  19. Thermal sensor based zinc oxide diode for low temperature applications

    Energy Technology Data Exchange (ETDEWEB)

    Ocaya, R.O. [Department of Physics, University of the Free State (South Africa); Al-Ghamdi, Ahmed [Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah, 21589 (Saudi Arabia); El-Tantawy, F. [Department of Physics, Faculty of Science, Suez Canal University, Ismailia (Egypt); Center of Nanotechnology, King Abdulaziz University, Jeddah (Saudi Arabia); Farooq, W.A. [Department of Physics and Astronomy, College of Science, King Saud University, Riyadh (Saudi Arabia); Yakuphanoglu, F., E-mail: fyhan@hotmail.com [Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah, 21589 (Saudi Arabia); Department of Physics, Faculty of Science, Firat University, Elazig, 23169 (Turkey)

    2016-07-25

    The device parameters of Al/p-Si/Zn{sub 1-x}Al{sub x}O-NiO/Al Schottky diode for x = 0.005 were investigated over the 50 K–400 K temperature range using direct current–voltage (I–V) and impedance spectroscopy. The films were prepared using the sol–gel method followed by spin-coating on p-Si substrate. The ideality factor, barrier height, resistance and capacitance of the diode were found to depend on temperature. The calculated barrier height has a mean. Capacitance–voltage (C–V) measurements show that the capacitance decreases with increasing frequency, suggesting a continuous distribution of interface states over the surveyed 100 kHz to 1 MHz frequency range. The interface state densities, N{sub ss}, of the diode were calculated and found to peak as functions of bias and temperature in two temperature regions of 50 K–300 K and 300 K–400 K. A peak value of approximately 10{sup 12}/eV cm{sup 2} was observed around 0.7 V bias for 350 K and at 3 × 10{sup 12}/eVcm{sup 2} around 2.2 V bias for 300 K. The relaxation time was found to average 4.7 μs over all the temperatures, but showing its lowest value of 1.58 μs at 300 K. It is seen that the interface states of the diode is controlled by the temperature. This suggests that Al/p-Si/Zn1-xAlxO-NiO/Al diode can be used as a thermal sensors for low temperature applications. - Highlights: • Al/pSi/Zn1-xAlxO-NiO/Al Schottky diode was fabricated by sol gel method. • The interface state density of the diode is controlled by the temperature. • Zinc oxide based diode can be used as a thermal sensor for low temperature applications.

  20. Oxygen transport and GeO2 stability during thermal oxidation of Ge

    Science.gov (United States)

    da Silva, S. R. M.; Rolim, G. K.; Soares, G. V.; Baumvol, I. J. R.; Krug, C.; Miotti, L.; Freire, F. L.; da Costa, M. E. H. M.; Radtke, C.

    2012-05-01

    Oxygen transport during thermal oxidation of Ge and desorption of the formed Ge oxide are investigated. Higher oxidation temperatures and lower oxygen pressures promote GeO desorption. An appreciable fraction of oxidized Ge desorbs during the growth of a GeO2 layer. The interplay between oxygen desorption and incorporation results in the exchange of O originally present in GeO2 by O from the gas phase throughout the oxide layer. This process is mediated by O vacancies generated at the GeO2/Ge interface. The formation of a substoichiometric oxide is shown to have direct relation with the GeO desorption.

  1. Oxide, interface, and border traps in thermal, N2O, and N2O-nitrided oxides

    International Nuclear Information System (INIS)

    Fleetwood, D.M.; Saks, N.S.

    1996-01-01

    We have combined thermally stimulated-current (TSC) and capacitance endash voltage (C endash V) measurements to estimate oxide, interface, and effective border trap densities in 6 endash 23 nm thermal, N 2 O, and N 2 O-nitrided oxides exposed to ionizing radiation or high-field electron injection. Defect densities depend strongly on oxide processing, but radiation exposure and moderate high-field stress lead to similar trapped hole peak thermal energy distributions (between ∼1.7 and ∼2.0 eV) for all processes. This suggests that similar defects dominate the oxide charge trapping properties in these devices. Radiation-induced hole and interface trap generation efficiencies (0.1%endash 1%) in the best N 2 O and N 2 O-nitrided oxides are comparable to the best radiation hardened oxides in the literature. After ∼10 Mrad(SiO 2 ) x-ray irradiation or ∼10 mC/cm 2 constant current Fowler endash Nordheim injection, effective border trap densities as high as ∼5x10 11 cm -2 are inferred from C endash V hysteresis. These measurements suggest irradiation and high-field stress cause similar border trap energy distributions. In each case, even higher densities of compensating trapped electrons in the oxides (up to 2x10 12 cm -2 ) are inferred from combined TSC and C endash V measurements. These trapped electrons prevent conventional C endash V methods from providing accurate estimates of the total oxide trap charge density in many irradiation or high-field stress studies. Fewer compensating electrons per trapped hole (∼26%±5%) are found for irradiation of N 2 O and N 2 O-nitrided oxides than for thermal oxides (∼46%±7%). (Abstract Truncated)

  2. Internal Temperature Control For Vibration Testers

    Science.gov (United States)

    Dean, Richard J.

    1996-01-01

    Vibration test fixtures with internal thermal-transfer capabilities developed. Made of aluminum for rapid thermal transfer. Small size gives rapid response to changing temperatures, with better thermal control. Setup quicker and internal ducting facilitates access to parts being tested. In addition, internal flows smaller, so less energy consumed in maintaining desired temperature settings.

  3. Monitoring thermally grown oxides under thermal barrier coatings using photoluminescence piezospectroscopy (PLPS)

    Energy Technology Data Exchange (ETDEWEB)

    Del Corno, A.; De Maria, L.; Rinaldi, C. [ERSE, Milan (Italy); Nalin, L.; Simms, N.J. [Cranfield Univ., Bedford (United Kingdom). Energy Technology Centre

    2010-07-01

    The use of thermal barrier coatings (TBCs) on cooled components in industrial gas turbine has enabled higher inlet gas temperatures to be used and hence higher efficiencies to be achieved, without increasing component metal temperatures. However TBCs have a complex coating structure that during high temperature exposure and thermal cycling modifies until TBC spalling which can result in dangerous over-heating of components. This paper reports the results of a TBC exposure programme planned to monitor TGOs development in an example TBC system in terms of both stress evolution within the TGOs and TGO growth. The COST538 reference TBC system was used: an yttria stabilised zirconia TBC applied to an Amdry 995 bond coat on an CMSX-4 substrate. Samples were in the form of 10 mm diameter bars, with the TBC applied to their curved surface. Coated samples were exposed in simulated combustion gases at temperatures 850, 900 and 950 C for periods of up to 10,000 hours. Every 1000 hours samples were cooled and weighed to monitor the progression of the oxidation: selected samples NDT inspected using PLPS and/or destructive examination. Cross-sections were prepared and examined in a scanning electron microscope (SEM) at multiple locations to determine TGO thickness distributions. PLPS spectra were measured and elaborated with a system self developed in ERSE, able to calculate and map the TGO residual stress values under columnar TBCs. So the positions could be evidenced where the damage of the TBC /TGO/BC interface is higher on the exposed bars. The data of TGO thickness distributions and PLPS stress measurement distributions were compared to the exposures carried out on samples to identify and quantify trends in their development. Metallography confirmed that the PLPs technique can reliably detect interface cracking before visible EB-PVD TBC spalling. (orig.)

  4. Iron Oxide Films Prepared by Rapid Thermal Processing for Solar Energy Conversion

    DEFF Research Database (Denmark)

    Wickman, B.; da Silva Fanta, Alice Bastos; Burrows, Andrew

    2017-01-01

    Hematite is a promising and extensively investigated material for various photoelectrochemical (PEC) processes for energy conversion and storage, in particular for oxidation reactions. Thermal treatments during synthesis of hematite are found to affect the performance of hematite electrodes...

  5. Thermally activated persulfate oxidation regeneration of NOM- and MTBE- spent granular activated carbon

    Science.gov (United States)

    Chemical oxidation is a developing technology used to regenerate contaminant-spent GAC. Chemical regeneration of GAC represents a viable option to thermal regeneration methods that are energy intensive resulting in significant consumption of fossil fuels and production of greenho...

  6. Interstitial pressure dependence of the thermal conductivity of some rare earth oxide powders

    International Nuclear Information System (INIS)

    Pradeep, P.

    1997-01-01

    Thermal transport properties of powdered materials depend upon interstitial gas pressure. The present study reports the experimental results for the effective thermal conductivity of three rare earth oxide powders viz. yttrium oxide, samarium oxide, and gadolinium oxide, at various interstitial pressures by using transient plane source (TPS) method. A theoretical model is also proposed for the interpretation of the variation of the effective thermal conductivity with interstitial gas pressure. Its validity is found to be good in low pressure range of 45 mm Hg to normal pressure when compared with the experimental results. Also an attempt has been made to calculate the variation of thermal conductivity with interstitial pressure in the high pressure range up to 2 kbar using the proposed model. (author)

  7. Thermal oxidative degradation behaviours of flame-retardant thermotropic liquid crystal copolyester/PET blends

    International Nuclear Information System (INIS)

    Du Xiaohua; Zhao Chengshou; Wang Yuzhong; Zhou Qian; Deng Yi; Qu Minghai; Yang Bing

    2006-01-01

    The flame retardancy and the thermal oxidative degradation behaviors of the blend of poly(ethylene terephthalate) (PET) with a kind of phosphorus-containing thermotropic liquid crystal copolyester (TLCP) with high flame retardancy (limited oxygen index, 70%) have been investigated by oxygen index test (LOI), UL-94 rating and thermogravimetric analysis (TGA) in air. The results show that TLCP can dramatically improve the flame retardancy and the melt dripping behavior of PET. Moreover, the apparent activation energies of thermal oxidative degradation of the blends were evaluated using Kissinger and Flynn-Wall-Ozawa methods. It is found that addition of TLCP improve thermal stability and restrain thermal decomposition of PET in air, especially at the primary degradation stage. Py-GC/MS analysis shows that there are remarkable changes in the pyrolysis products when TLCP are blended into PET. The interaction between TLCP and PET has changed their thermal oxidative degradation mechanism

  8. Rapid synthesis of tin oxide nanostructures by microwave-assisted thermal oxidation for sensor applications

    Science.gov (United States)

    Phadungdhitidhada, S.; Ruankham, P.; Gardchareon, A.; Wongratanaphisan, D.; Choopun, S.

    2017-09-01

    In the present work nanostructures of tin oxides were synthesized by a microwave-assisted thermal oxidation. Tin precursor powder was loaded into a cylindrical quartz tube and further radiated in a microwave oven. The as-synthesized products were characterized by scanning electron microscope, transmission electron microscope, and x-ray diffractometer. The results showed that two different morphologies of SnO2 microwires (MWs) and nanoparticles (NPs) were obtained in one minute of microwave radiation under atmospheric ambient. A few tens of the SnO2 MWs with the length of 10-50 µm were found. Some parts of the MWs were decorated with the SnO2 NPs. However, most of the products were SnO2 NPs with the diameter ranging from 30-200 nm. Preparation under loosely closed system lead to mixed phase SnO-SnO2 NPs with diameter of 30-200 nm. The single-phase of SnO2 could be obtained by mixing the Sn precursor powders with CuO2. The products were mostly found to be SnO2 nanowires (NWs) and MWs. The diameter of SnO2 NWs was less than 50 nm. The SnO2 NPs, MWs, and NWs were in the cassiterite rutile structure phase. The SnO NPs was in the tetragonal structure phase. The growth direction of the SnO2 NWs was observed in (1 1 0) and (2 2 1) direction. The ethanol sensor performance of these tin oxide nanostructures showed that the SnO-SnO2 NPs exhibited extremely high sensitivity. Invited talk at 5th Thailand International Nanotechnology Conference (Nano Thailand-2016), 27-29 November 2016, Nakhon Ratchasima, Thailand.

  9. Mechanism of antioxidant interaction on polymer oxidation by thermal and radiation ageing

    International Nuclear Information System (INIS)

    Seguchi, Tadao; Tamura, Kiyotoshi; Shimada, Akihiko; Sugimoto, Masaki; Kudoh, Hisaaki

    2012-01-01

    The mechanism of polymer oxidation by radiation and thermal ageing was investigated for the life evaluation of cables installed in radiation environments. The antioxidant as a stabilizer was very effective for thermal oxidation with a small content in polymers, but was not effective for radiation oxidation. The ionizing radiation induced the oxidation to result in chain scission even at low temperature, because the free radicals were produced and the antioxidant could not stop the oxidation of radicals with the chain scission. A new mechanism of antioxidant effect for polymer oxidation was proposed. The effect of antioxidant was not the termination of free radicals in polymer chains such as peroxy radicals, but was the depression of initial radical formation in polymer chains by thermal activation. The antioxidant molecule was assumed to delocalize the activated energy in polymer chains by the Boltzmann statics (distribution) to result in decrease in the probability of radical formation at a given temperature. The interaction distance (delocalization volume) by one antioxidant molecule was estimated to be 5–10 nm by the radius of sphere in polymer matrix, though the value would depend on the chemical structure of antioxidant. - Highlights: ► Interaction of antioxidant on polymer oxidation is discussed for thermal and radiation ageings. ► Antioxidant is very effective for thermal oxidation, but not for radiation induced oxidation. ► Interaction of antioxidant is not the termination reaction of radicals on polymers. ► Antioxidant is supposed to reduce the provability of polymer radical formation by thermal activation. ► Mechanism of polymer oxidation may not be chain reaction via peroxy radical and hydro-peroxide.

  10. Development of roller type side slip tester; Roller shiki side slip tester no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Nishiyama, S [Hiroshima City Industrial Technology Institute, Hiroshima (Japan); Harada, S; Harada, K

    1997-10-01

    This paper presents a new development of roller type side slip tester (RTSSI). The test equipment consists of four parts, which are developed in this research. These are a roller part, a control part, a remote control part and a CRT part. In this study, we especially investigated the mechanism and performance between tire and roller. We analyzed the amount of side slip with various toe angles. The developed tester is examined under the conditions that is considered in industrial applications. We investigated the influences of toe angle, size of tire, pressure of tire, coefficient of friction between tire and roller, pushing force of tire, revolution velocity of roller, axle load and so on. The validity of the developed RTSST is confirmed under these conditions. It was found that the RTSST can be used in practical use. Some measurement results are presented in the form of parametric plots. And we also compared measurements data between the RTSST and that of flat type using several automobiles. 4 refs., 8 figs., 4 tabs.

  11. Iridescent cellulose nanocrystal/polyethylene oxide composite films with low coefficient of thermal expansion

    Science.gov (United States)

    Jairo A. Diaz; Julia L. Braun; Robert J. Moon; Jeffrey P. Youngblood

    2015-01-01

    Simultaneous control over optical and thermal properties is particularly challenging and highly desired in fields like organic electronics. Here we incorporated cellulose nanocrystals (CNCs) into polyethylene oxide (PEO) in an attempt to preserve the iridescent CNC optical reflection given by their chiral nematic organisation, while reducing the composite thermal...

  12. Infrared absorption study of ammonium uranates and uranium oxide powders formed during their thermal decomposition

    International Nuclear Information System (INIS)

    Rofail, N.H.; ELfekey, S.A.

    1992-01-01

    Ammonium uranates (AU) were precipitated from a nuclear-pure uranyl nitrate solution using different precipitating agents. IR spectra of the obtained uranates and oxides formed during their thermal decomposition have been studied. The results indicated that the precipitating agent, mode of stirring, washing and calcining temperature are important factors for a specific oxide formation.4 FIG., 3 TAB

  13. Surface and sub-surface thermal oxidation of thin ruthenium films

    NARCIS (Netherlands)

    Coloma Ribera, R.; van de Kruijs, Robbert Wilhelmus Elisabeth; Kokke, S.; Zoethout, E.; Yakshin, Andrey; Bijkerk, Frederik

    2014-01-01

    A mixed 2D (film) and 3D (nano-column) growth of ruthenium oxide has been experimentally observed for thermally oxidized polycrystalline ruthenium thin films. Furthermore, in situ x-ray reflectivity upon annealing allowed the detection of 2D film growth as two separate layers consisting of low

  14. Electrospray painted article containing thermally exfoliated graphite oxide and method for their manufacture

    Science.gov (United States)

    Korkut, Sibel (Inventor); Prud'Homme, Robert K. (Inventor); Aksay, Ilhan A. (Inventor)

    2011-01-01

    A painted polymer part containing a conductive polymer composition containing at least one polymer and a modified graphite oxide material, which is a thermally exfoliated graphite oxide with a surface area of from about 300 sq m/g to 2600 sq m/g, wherein the painted polymer part has been electrospray painted.

  15. Cuprous oxide thin films prepared by thermal oxidation of copper layer. Morphological and optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Karapetyan, Artak, E-mail: karapetyan@cinam.univ-mrs.fr [Aix Marseille Université, CINaM, 13288, Marseille (France); Institute for Physical Research of NAS of Armenia, Ashtarak-2 0203 (Armenia); Reymers, Anna [Russian-Armenian (Slavonic) University, H.Emin st.123, Yerevan 375051 (Armenia); Giorgio, Suzanne; Fauquet, Carole [Aix Marseille Université, CINaM, 13288, Marseille (France); Sajti, Laszlo [Laser Zentrum Hannover e.V. Hollerithallee 8, 30419 Hannover (Germany); Nitsche, Serge [Aix Marseille Université, CINaM, 13288, Marseille (France); Nersesyan, Manuk; Gevorgyan, Vladimir [Russian-Armenian (Slavonic) University, H.Emin st.123, Yerevan 375051 (Armenia); Marine, Wladimir [Aix Marseille Université, CINaM, 13288, Marseille (France)

    2015-03-15

    Structural and optical characterization of crystalline Cu{sub 2}O thin films obtained by thermal oxidation of Cu films at two different temperatures 800 °C and 900 °C are investigated in this work. X-ray diffraction measurements indicate that synthesized films consist of single Cu{sub 2}O phase without any interstitial phase and show a nano-grain structure. Scanning Electron Microscopy observations indicate that the Cu{sub 2}O films have a micro-scale roughness whereas High Resolution Transmission Electron Microscopy highlights that the nanocrystalline structure is formed by superposition of nearly spherical nanocrystals smaller than 30 nm. Photoluminescence spectra of these films exhibit at room temperature two well-resolved emission peaks at 1.34 eV due to defects energy levels and at 1.97 eV due to phonon-assisted recombination of the 1s orthoexciton in both film series. Emission characteristics depending on the laser power is deeply investigated to determine the origin of recorded emissions. Time-integrated spectra of the 1s orthoexciton emission reveals the presence of oxygen defects below the conduction band edge under non-resonant two-photon excitation using a wide range of excitations wavelengths. Optical absorption coefficients at room temperature are obtained from an accurate analysis of their transmission and reflection spectra, whereas the optical band gap energy is estimated at about 2.11 eV. Results obtained are of high relevance especially for potential applications in semiconductor devices such as solar cells, optical sources and detectors. - Highlights: • Nanostructured Cu{sub 2}O thin films were synthesized by thermal oxidation of Cu films. • The PL spectra of nanostructured thin films revealed two well-resolved emission peaks. • The PL properties were investigated under a broad range of experimental conditions. • Inter-band transition in the infrared range has been associated to V{sub Cu} and V{sub O} vacancies. • Absorption

  16. Iodine doping effects on the lattice thermal conductivity of oxidized polyacetylene nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Bi, Kedong, E-mail: lishi@mail.utexas.edu, E-mail: kedongbi@seu.edu.cn [Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments, School of Mechanical Engineering, Southeast University, Nanjing 211189 (China); Department of Mechanical Engineering, University of Texas at Austin, Austin, Texas 78712 (United States); Weathers, Annie; Pettes, Michael T.; Shi, Li, E-mail: lishi@mail.utexas.edu, E-mail: kedongbi@seu.edu.cn [Department of Mechanical Engineering, University of Texas at Austin, Austin, Texas 78712 (United States); Matsushita, Satoshi; Akagi, Kazuo [Department of Polymer Chemistry, Kyoto University, Kyoto 615-8510 (Japan); Goh, Munju [Department of Polymer Chemistry, Kyoto University, Kyoto 615-8510 (Japan); Institute of Advanced Composite Materials, Korea Institute of Science and Technology (KIST), Eunha-ri san 101, Bondong-eup, Wanju-gun, Jeolabuk-do 565-905 (Korea, Republic of)

    2013-11-21

    Thermal transport in oxidized polyacetylene (PA) nanofibers with diameters in the range between 74 and 126 nm is measured with the use of a suspended micro heater device. With the error due to both radiation and contact thermal resistance corrected via a differential measurement procedure, the obtained thermal conductivity of oxidized PA nanofibers varies in the range between 0.84 and 1.24 W m{sup −1} K{sup −1} near room temperature, and decreases by 40%–70% after iodine doping. It is also found that the thermal conductivity of oxidized PA nanofibers increases with temperature between 100 and 350 K. Because of exposure to oxygen during sample preparation, the PA nanofibers are oxidized to be electrically insulating before and after iodine doping. The measurement results reveal that iodine doping can result in enhanced lattice disorder and reduced lattice thermal conductivity of PA nanofibers. If the oxidation issue can be addressed via further research to increase the electrical conductivity via doping, the observed suppressed lattice thermal conductivity in doped polymer nanofibers can be useful for the development of such conducting polymer nanostructures for thermoelectric energy conversion.

  17. Iodine doping effects on the lattice thermal conductivity of oxidized polyacetylene nanofibers

    International Nuclear Information System (INIS)

    Bi, Kedong; Weathers, Annie; Pettes, Michael T.; Shi, Li; Matsushita, Satoshi; Akagi, Kazuo; Goh, Munju

    2013-01-01

    Thermal transport in oxidized polyacetylene (PA) nanofibers with diameters in the range between 74 and 126 nm is measured with the use of a suspended micro heater device. With the error due to both radiation and contact thermal resistance corrected via a differential measurement procedure, the obtained thermal conductivity of oxidized PA nanofibers varies in the range between 0.84 and 1.24 W m −1  K −1 near room temperature, and decreases by 40%–70% after iodine doping. It is also found that the thermal conductivity of oxidized PA nanofibers increases with temperature between 100 and 350 K. Because of exposure to oxygen during sample preparation, the PA nanofibers are oxidized to be electrically insulating before and after iodine doping. The measurement results reveal that iodine doping can result in enhanced lattice disorder and reduced lattice thermal conductivity of PA nanofibers. If the oxidation issue can be addressed via further research to increase the electrical conductivity via doping, the observed suppressed lattice thermal conductivity in doped polymer nanofibers can be useful for the development of such conducting polymer nanostructures for thermoelectric energy conversion

  18. A recommendation for the thermal conductivity of oxide fuels

    International Nuclear Information System (INIS)

    Kang, K. H.; Ryu, H. J.; Song, K. C.; Yang, M. S.; Na, S. H.; Lee, Y. W.; Moon, H. S.; Kim, H. S.

    2004-01-01

    The thermal conductivity of nuclear fuel is one of the most important properties because it affects the fuel operating temperature. Therefore, it influences almost all the important processes occurred in nuclear fuel during irradiation, such as gas release, swelling and grain growth. The model of the thermal conductivity of nuclear fuel should be used in the codes to evaluate the performance of it analytically and be required in the nuclear fuel research and development. The thermal conductivity, k, of UO 2 depends on the deviation from stoichiometry, x, the burnup, b, and the fractional porosity, p, as well as the temperature, T: k = k(x, b, p, T), (1) Changes in thermal conductivity occur during irradiation because of fission-gas bubble formation, pores, cracks, fission product build-up and possible changes in the oxygen to uranium ratio (O/U). The dependence on temperature and porosity has been well studied and incorporated in computer codes used for the in-pile fuel behavior analysis. There are several studies on the effect of impurity on the thermal conductivity of UO 2 . In this paper, the variables affected on the thermal conductivity were studied. The available data of the thermal conductivity of UO 2 , UO 2+x , (U, Pu)O 2 , (U, Pu)O 2 and simulated fuel for irradiation fuel were reviewed and analyzed. The best models were recommended

  19. Thermal oxidation of tungsten-based sputtered coatings

    International Nuclear Information System (INIS)

    Louro, C.; Cavaleiro, A.

    1997-01-01

    The effect of the addition of nickel, titanium, and nitrogen on the air oxidation behavior of W-based sputtered coatings in the temperature range 600 to 800 C was studied. In some cases these additions significantly improved the oxidation resistance of the tungsten coatings. As reported for bulk tungsten, all the coatings studied were oxidized by layers following a parabolic law. Besides WO 3 and WO x phases detected in all the oxidized coatings, TiO 2 and NiWO 4 were also detected for W-Ti and W-Ni films, respectively. WO x was present as an inner protective compact layer covered by the porous WO 3 oxide. The best oxidation resistance was found for W-Ti and W-N-Ni coatings which also presented the highest activation energies (E a = 234 and 218 kJ/mol, respectively, as opposed to E a ∼ 188 kJ/mol for the other coatings). These lower oxidation weight gains were attributed to the greater difficulty of the inward diffusion of oxygen ions for W-Ti films, owing to the formation of fine particles of TiO 2 , and the formation of the external, more protective layer of NiWO 4 for W-N-Ni coatings

  20. Thermal processing and native oxidation of silicon nanoparticles

    International Nuclear Information System (INIS)

    Winters, Brandon J.; Holm, Jason; Roberts, Jeffrey T.

    2011-01-01

    In this study, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and electron energy loss spectroscopy (EELS) were used to investigate in-air oxidation of silicon nanoparticles ca. 11 nm in diameter. Particle samples were prepared first by extracting them from an RF plasma synthesis reactor, and then heating them in an inert carrier gas stream. The resulting particles had varying surface hydrogen coverages and relative amounts of SiH x (x = 1, 2, and 3), depending on the temperature to which they had been heated. The particles were allowed to oxidize in-air for several weeks. FTIR, XPS, and EELS analyses that were performed during this period clearly establish that adsorbed hydrogen retards oxidation, although in complex ways. In particular, particles that have been heated to intermediate hydrogen coverages oxidize more slowly in air than do freshly generated particles that have a much higher hydrogen content. In addition, the loss of surface hydride species at high processing temperatures results in fast initial oxidation and the formation of a self-limiting oxide layer. Analogous measurements made on deuterium-covered particles show broadly similar behavior; i.e., that oxidation is the slowest at some intermediate coverage of adsorbed deuterium.

  1. Mosaic-shaped cathode for highly durable solid oxide fuel cell under thermal stress

    Science.gov (United States)

    Joo, Jong Hoon; Jeong, Jaewon; Kim, Se Young; Yoo, Chung-Yul; Jung, Doh Won; Park, Hee Jung; Kwak, Chan; Yu, Ji Haeng

    2014-02-01

    In this study, we propose a novel "mosaic structure" for a SOFC (solid oxide fuel cell) cathode with high thermal expansion to improve the stability against thermal stress. Self-organizing mosaic-shaped cathode has been successfully achieved by controlling the amount of binder in the dip-coating solution. The anode-supported cell with mosaic-shaped cathode shows itself to be highly durable performance for rapid thermal cycles, however, the performance of the cell with a non-mosaic cathode exhibits severe deterioration originated from the delamination at the cathode/electrolyte interface after 7 thermal cycles. The thermal stability of an SOFC cathode can be evidently improved by controlling the surface morphology. In view of the importance of the thermal expansion properties of the cathode, the effects of cathode morphology on the thermal stress stability are discussed.

  2. In Situ Study of Thermal Stability of Copper Oxide Nanowires at Anaerobic Environment

    Directory of Open Access Journals (Sweden)

    Lihui Zhang

    2014-01-01

    Full Text Available Many metal oxides with promising electrochemical properties were developed recently. Before those metal oxides realize the use as an anode in lithium ion batteries, their thermal stability at anaerobic environment inside batteries should be clearly understood for safety. In this study, copper oxide nanowires were investigated as an example. Several kinds of in situ experiment methods including in situ optical microscopy, in situ Raman spectrum, and in situ transmission electron microscopy were adopted to fully investigate their thermal stability at anaerobic environment. Copper oxide nanowires begin to transform as copper(I oxide at about 250°C and finish at about 400°C. The phase transformation proceeds with a homogeneous nucleation.

  3. Oxygen isotopic exchange occurring during dry thermal oxidation of 6H SiC

    Energy Technology Data Exchange (ETDEWEB)

    Vickridge, I.C. E-mail: vickridge@gps.jussieu.fr; Tromson, D.; Trimaille, I.; Ganem, J.-J.; Szilagyi, E.; Battistig, G

    2002-05-01

    SiC is a large band gap semiconductor, promising for high power and high frequency devices. The thermal oxide is SiO{sub 2} however the growth rates of thermal oxide on SiC are substantially slower than on Si, and different along the polar directions (<0 0 0 1-bar> and <0 0 0 1> in the hexagonal polytypes). Thorough understanding of the oxide growth mechanisms may give us new insights into the nature of the SiO{sub 2}/SiC interface, crucial for device applications. We have determined growth kinetics for ultra-dry thermal oxidation of 6H SiC at 1100 deg. C for pressures from 3 to 200 mbar. At 3 mbar, the lowest pressure studied, the oxide growth rates along the two polar directions are virtually the same. At higher pressures growth is faster on the carbon-terminated (0 0 0 1-bar) face. After consecutive oxidations at 1100 deg. C and 100 mbar in {sup 18}O{sub 2} and {sup 16}O{sub 2} gases, {sup 18}O depth profiles show significant isotopic exchange and oxygen movement within the oxide during oxidation.

  4. Thermal oxidation of reactively sputtered amorphous W80N20 films

    International Nuclear Information System (INIS)

    Vu, Q.T.; Pokela, P.J.; Garden, C.L.; Kolawa, E.; Raud, S.; Nicolet, M.

    1990-01-01

    The oxidation behavior of reactively sputtered amorphous tungsten nitride of composition W 80 N 20 was investigated in dry and wet oxidizing ambient in the temperature range of 450 degree C--575 degree C. A single WO 3 oxide phase is observed. The growth of the oxide follows a parabolic time dependence which is attributed to a process controlled by the diffusivity of the oxidant in the oxide. The oxidation process is thermally activated with an activation energy of 2.5±0.05 eV for dry ambient and 2.35±0.05 eV for wet ambient. The pre-exponential factor of the reaction constant for dry ambient is 1.1x10 21 A 2 /min; that for wet ambient is only about 10 times less and is equal to 1.3x10 20 A 2 /min

  5. A Novel Investigation of the Formation of Titanium Oxide Nanotubes on Thermally Formed Oxide of Ti-6Al-4V.

    Science.gov (United States)

    Butt, Arman; Hamlekhan, Azhang; Patel, Sweetu; Royhman, Dmitry; Sukotjo, Cortino; Mathew, Mathew T; Shokuhfar, Tolou; Takoudis, Christos

    2015-10-01

    Traditionally, titanium oxide (TiO2) nanotubes (TNTs) are anodized on Ti-6Al-4V alloy (Ti-V) surfaces with native TiO2 (amorphous TiO2); subsequent heat treatment of anodized surfaces has been observed to enhance cellular response. As-is bulk Ti-V, however, is often subjected to heat treatment, such as thermal oxidation (TO), to improve its mechanical properties. Thermal oxidation treatment of Ti-V at temperatures greater than 200°C and 400°C initiates the formation of anatase and rutile TiO2, respectively, which can affect TNT formation. This study aims at understanding the TNT formation mechanism on Ti-V surfaces with TO-formed TiO2 compared with that on as-is Ti-V surfaces with native oxide. Thermal oxidation-formed TiO2 can affect TNT formation and surface wettability because TO-formed TiO2 is expected to be part of the TNT structure. Surface characterization was carried out with field emission scanning electron microscopy, energy dispersive x-ray spectroscopy, water contact angle measurements, and white light interferometry. The TNTs were formed on control and 300°C and 600°C TO-treated Ti-V samples, and significant differences in TNT lengths and surface morphology were observed. No difference in elemental composition was found. Thermal oxidation and TO/anodization treatments produced hydrophilic surfaces, while hydrophobic behavior was observed over time (aging) for all samples. Reduced hydrophobic behavior was observed for TO/anodized samples when compared with control, control/anodized, and TO-treated samples. A method for improved surface wettability and TNT morphology is therefore discussed for possible applications in effective osseointegration of dental and orthopedic implants.

  6. Revisiting the effects of organic solvents on the thermal reduction of graphite oxide

    International Nuclear Information System (INIS)

    Barroso-Bujans, Fabienne; Fierro, José Luis G.; Alegría, Angel; Colmenero, Juan

    2011-01-01

    Highlights: ► Retention of organic solvent on graphite oxide interlayer space. ► Decreasing exfoliation temperature. ► Close link between structure and thermal behavior of solvent treated graphite oxide. ► Restacking inhibition of thermally reduced graphite oxide sheets. ► Changes in kinetic mechanisms of thermal reduction. - Abstract: Treatment of graphite oxide (GO) with organic solvents via sorption from either liquid or gas phase, and subsequent desorption, induces profound changes in the layered GO structure: loss of stacking order, retention of trace amounts of solvents and decreasing decomposition temperature. This study presents new evidences of the effect of organic solvents on the thermal reduction of GO by means of thermogravimetric analysis, X-ray diffraction and X-ray photoelectron spectroscopy. The results reveal a relative higher decrease of the oxygen amounts in solvent-treated GO as compared to untreated GO and the restacking inhibition of the thermally reduced GO sheets upon slow heating. The kinetic experiments evidence changes occurring in the reduction mechanisms of the solvent-treated GO, which support the close link between GO structure and thermal properties.

  7. Deuterium permeation behavior of HTUPS4 steel with thermal oxidation layer

    International Nuclear Information System (INIS)

    Xu, Yu-Ping; Liu, Feng; Zhao, Si-Xiang; Li, Xiao-Chun; Wang, Jing; An, Zhong-Qing; Lu, Tao; Liu, Hao-Dong; Ding, Fang; Zhou, Hai-Shan; Luo, Guang-Nan

    2016-01-01

    The permeation behavior of creep-resistant, Al 2 O 3 -forming HTUPS austenitic stainless steels was studied using a gas driven permeation (GDP) device. The steel samples were first thermal oxidized at air condition, followed by GDP experiments. The permeability and diffusion coefficients of oxidized samples and bare 316L steels were derived and compared. In order to characterize the oxide layer, X-ray photoelectron spectroscopy was performed. An oxide layer with a thickness of 200 nm which mainly consists of Al 2 O 3 was detected.

  8. Effects of solid fission products forming dissolved oxide (Nd) and metallic precipitate (Ru) on the thermal conductivity of uranium base oxide fuel

    International Nuclear Information System (INIS)

    Kim, Dong-Joo; Yang, Jae-Ho; Kim, Jong-Hun; Rhee, Young-Woo; Kang, Ki-Won; Kim, Keon-Sik; Song, Kun-Woo

    2007-01-01

    The effects of solid fission products on the thermal conductivity of uranium base oxide nuclear fuel were experimentally investigated. Neodymium (Nd) and ruthenium (Ru) were added to represent the physical states of solid fission products such as 'dissolved oxide' and 'metallic precipitate', respectively. Thermal conductivity was determined on the basis of the thermal diffusivity, density and specific heat values. The effects of the additives on the thermal conductivity were quantified in the form of the thermal resistivity equation - the reciprocal of the phonon conduction equation - which was determined from the measured data. It is concluded that the thermal conductivity of the irradiated nuclear fuel is affected by both the 'dissolved oxide' and the 'metallic precipitate', however, the effects are in the opposite direction and the 'dissolved oxide' influences the thermal conductivity more significantly than that of the 'metallic precipitate'

  9. Evolution of thermal stress and failure probability during reduction and re-oxidation of solid oxide fuel cell

    Science.gov (United States)

    Wang, Yu; Jiang, Wenchun; Luo, Yun; Zhang, Yucai; Tu, Shan-Tung

    2017-12-01

    The reduction and re-oxidation of anode have significant effects on the integrity of the solid oxide fuel cell (SOFC) sealed by the glass-ceramic (GC). The mechanical failure is mainly controlled by the stress distribution. Therefore, a three dimensional model of SOFC is established to investigate the stress evolution during the reduction and re-oxidation by finite element method (FEM) in this paper, and the failure probability is calculated using the Weibull method. The results demonstrate that the reduction of anode can decrease the thermal stresses and reduce the failure probability due to the volumetric contraction and porosity increasing. The re-oxidation can result in a remarkable increase of the thermal stresses, and the failure probabilities of anode, cathode, electrolyte and GC all increase to 1, which is mainly due to the large linear strain rather than the porosity decreasing. The cathode and electrolyte fail as soon as the linear strains are about 0.03% and 0.07%. Therefore, the re-oxidation should be controlled to ensure the integrity, and a lower re-oxidation temperature can decrease the stress and failure probability.

  10. The oxidation behavior of classical thermal barrier coatings exposed to extreme temperature

    Directory of Open Access Journals (Sweden)

    Alina DRAGOMIRESCU

    2017-03-01

    Full Text Available Thermal barrier coatings (TBC are designed to protect metal surfaces from extreme temperatures and improve their resistance to oxidation during service. Currently, the most commonly used systems are those that have the TBC structure bond coat (BC / top coat (TC layers. The top coat layer is a ceramic layer. Oxidation tests are designed to identify the dynamics of the thermally oxide layer (TGO growth at the interface of bond coat / top coat layers, delamination mechanism and the TBC structural changes induced by thermal conditions. This paper is a short study on the evolution of aluminum oxide protective layer along with prolonged exposure to the testing temperature. There have been tested rectangular specimens of metal super alloy with four surfaces coated with a duplex thermal barrier coating system. The specimens were microscopically and EDAX analyzed before and after the tests. In order to determine the oxide type, the samples were analyzed using X-ray diffraction. The results of the investigation are encouraging for future studies. The results show a direct relationship between the development of the oxide layer and long exposure to the test temperature. Future research will focus on changing the testing temperature to compare the results.

  11. Pyrolysis and thermal oxidation kinetics of sugar mill press mud

    International Nuclear Information System (INIS)

    Gangavati, P.B.; Safi, M.J.; Singh, A.; Prasad, B.; Mishra, I.M.

    2005-01-01

    Press mud, a solid waste obtained from the sugar mills, has the potential of energy generation through pyrolysis and gasification. The paper reports its proximate and ultimate analyses, deformation and fusion ash temperatures, lower and higher heating values, physico-chemical and thermal degradation in nitrogen and air atmospheres. The thermal degradation was conducted in a thermogravimetric analyzer from room temperature to 900 deg C at heating rates of 20 and 40 K min -1 . The thermogravimetric, derivative thermogravimetric and differential thermal analyses were carried out to determine the rate of volatiles evolution, the effect of heating rates on the thermal degradation characteristics and to determine the global mass loss kinetics of thermal degradation. The thermal degradation was found to occur in several distinct phases: each phase giving volatile evolution in an independent parallel lump. Each decomposition phase was modeled by a single irreversible reaction with respect to the solid mass. Global mass loss kinetics was also determined for the entire decomposition process, as if occurring in one single step. The integral and differential techniques were used for the determination of kinetic parameters. Using the method of Agrawal and Sivasubramanian [R.K. Agrawal, M.S. Sivasubramanian, AIChE J. 33 (1987) 7] for the total degradation zone, the orders of reaction were found in the range of 1.00-2.50 in both the atmospheres (i.e. nitrogen and air) and the activation energy in the range of 27.84-33.44 and 57.41-88.92 kJ mol -1 in nitrogen and air, respectively. The pre-exponential factor was found in the range of 32.1-95.1 and 5.10 x 10 4 to 5.46 x 10 9 min -1 in nitrogen and air atmospheres, respectively

  12. Characteristics of ceramic oxide nanoparticles synthesized using radio frequency produced thermal plasma

    International Nuclear Information System (INIS)

    Dhamale, Gayatri D.; Mathe, V.L.; Bhoraskar, S.V.; Ghorui, S.

    2015-01-01

    Thermal plasma devices with their unique processing capabilities due to extremely high temperature and steep temperature gradient play an important role in synthesis of ultrafine powders in the range of 100nm or less. High temperature gas phase synthesis in Radio Frequency (RF) thermal plasma reactor is an attractive route for mass production of refractory nanoparticles, especially in the case of rare earth oxides. Here we report synthesis of Yttrium Oxide (Y_2O_3), Neodymium Oxide (Nd_2O_3) and Aluminum Oxide (Al_2O_3) in an inductively coupled radio frequency thermal plasma reactor. Synthesized nanoparticles find wide application in various fields like gate dielectrics, photocatalytic applications, laser devices and photonics. Nano sized Yttrium oxide, Neodymium Oxide and Aluminum oxide powders were separately synthesized in an RF plasma reactor starting with micron sized irregular shaped precursor powders. The system was operated at 3MHz in atmospheric pressure at different power levels. Synthesized powders were scrapped out from different deposition locations inside the reactor and characterized for their phase, morphology, particle size, crystallinity and other characteristic features. Highly crystalline nature of the synthesized particles, narrow size distribution, location dependent phase formation, and distinct variation in the inherent defect states compared to the bulk are some of the important characteristic features observed

  13. Preparation of polyvinyl alcohol graphene oxide phosphonate film and research of thermal stability and mechanical properties.

    Science.gov (United States)

    Li, Jihui; Song, Yunna; Ma, Zheng; Li, Ning; Niu, Shuai; Li, Yongshen

    2018-05-01

    In this article, flake graphite, nitric acid, peroxyacetic acid and phosphoric acid are used to prepare graphene oxide phosphonic and phosphinic acids (GOPAs), and GOPAs and polyvinyl alcohol (PVA) are used to synthesize polyvinyl alcohol graphene oxide phosphonate and phosphinate (PVAGOPs) in the case of faint acidity and ultrasound irradiation, and PVAGOPs are used to fabricate PVAGOPs film, and the structure and morphology of GOPAs, PVAGOPs and PVAGOPs film are characterized, and the thermal stability and mechanical properties of PVAGOPs film are investigated. Based on these, it has been proved that GOPAs consist of graphene oxide phosphonic acid and graphene oxide phosphinic acid, and there are CP covalent bonds between them, and PVAGOPs are composed of GOPAs and PVA, and there are six-member lactone rings between GOPAs and PVA, and the thermal stability and mechanical properties of PVAGOPs film are improved effectively. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. Iron Oxide Films Prepared by Rapid Thermal Processing for Solar Energy Conversion.

    Science.gov (United States)

    Wickman, B; Bastos Fanta, A; Burrows, A; Hellman, A; Wagner, J B; Iandolo, B

    2017-01-16

    Hematite is a promising and extensively investigated material for various photoelectrochemical (PEC) processes for energy conversion and storage, in particular for oxidation reactions. Thermal treatments during synthesis of hematite are found to affect the performance of hematite electrodes considerably. Herein, we present hematite thin films fabricated via one-step oxidation of Fe by rapid thermal processing (RTP). In particular, we investigate the effect of oxidation temperature on the PEC properties of hematite. Films prepared at 750 °C show the highest activity towards water oxidation. These films show the largest average grain size and the highest charge carrier density, as determined from electron microscopy and impedance spectroscopy analysis. We believe that the fast processing enabled by RTP makes this technique a preferred method for investigation of novel materials and architectures, potentially also on nanostructured electrodes, where retaining high surface area is crucial to maximize performance.

  15. Role of oxides and porosity on high temperature oxidation of liquid fuelled HVOF thermal sprayed Ni50Cr coatings

    OpenAIRE

    Song, B.; Bai, M.; Voisey, K.T.; Hussain, Tanvir

    2017-01-01

    High chromium content in Ni50Cr thermally sprayed coatings can generate a dense and protective scale at the surface of coating. Thus, the Ni50Cr coating is widely used in high temperature oxidation and corrosion applications. A commercially available gas atomized Ni50Cr powder was sprayed onto a power plant steel (ASME P92) using a liquid fuelled high velocity oxy-fuel (HVOF) thermal spray with three processing parameters in this study. Microstructure of as-sprayed coatings was examined using...

  16. Behavior of sorption and thermal desorption of fission products from loaded metal oxide exchangers

    International Nuclear Information System (INIS)

    Buerck, J.

    1986-08-01

    A new sublimation method for the concentration and purification of 99 Mo, produced by the fission of 235 U with thermal neutrons, has been developed to replace the present final decontamination steps in the various well established 99 Mo separation processes. A distinct simplification and shortening of the actual procedure is obtained by combining the chromatographic sorption on the SnO 2 -exchanger with the direct thermal desorption of the Mo product from the oxide. (orig./PW) [de

  17. Behavior of mixed-oxide fuel subjected to multiple thermal transients

    International Nuclear Information System (INIS)

    Fenske, G.R.; Neimark, L.A.; Poeppel, R.B.; Hofman, G.L.

    1985-01-01

    The microstructural behavior of irradiated mixed-oxide fuel subjected to multiple, mild thermal transients was investigated using direct electrical heating. The results demonstrate that significant intergranular porosity, accompanied by large-scale (>90%) release of the retained fission gas, developed as a result of the cyclic heating. Microstructural examination of the fuel indicated that thermal-shock-induced cracking of the fuel contributed significantly to the increased swelling and gas release. 29 refs., 12 figs

  18. Behavior of mixed-oxide fuel subjected to multiple thermal transients

    International Nuclear Information System (INIS)

    Fenske, G.R.; Hofman, G.L.; Neimark, L.A.; Poeppel, R.B.

    1983-11-01

    The microstructural behavior of irradiated mixed-oxide fuel subjected to multiple, mild thermal transients was investigated using direct electrical heating. The results demonstrate that significant intergranular porosity, accompanied by large-scale (>90%) release of the retained fission gas, developed as a result of the cyclic heating. Microstructural examination of the fuel indicated that thermal-shock-induced cracking of the fuel contributed significantly to the increased swelling and gas release

  19. Thermally induced all-optical inverter and dynamic hysteresis loops in graphene oxide dispersions.

    Science.gov (United States)

    Melle, Sonia; Calderón, Oscar G; Egatz-Gómez, Ana; Cabrera-Granado, E; Carreño, F; Antón, M A

    2015-11-01

    We experimentally study the temporal dynamics of amplitude-modulated laser beams propagating through a water dispersion of graphene oxide sheets in a fiber-to-fiber U-bench. Nonlinear refraction induced in the sample by thermal effects leads to both phase reversing of the transmitted signals and dynamic hysteresis in the input-output power curves. A theoretical model including beam propagation and thermal lensing dynamics reproduces the experimental findings.

  20. Measurement of the diffusion length of thermal neutrons in the beryllium oxide

    International Nuclear Information System (INIS)

    Koechlin, J.C.; Martelly, J.; Duggal, V.P.

    1955-01-01

    The diffusion length of thermal neutrons in the beryllium oxide has been obtained while studying the spatial distribution of the neutrons in a massive parallelepiped of this matter placed before the thermal column of the reactor core of Saclay. The mean density of the beryllium oxide (BeO) is 2,95 gr/cm 3 , the mean density of the massif is 2,92 gr/cm 3 . The value of the diffusion length, deducted of the done measures, is: L = 32,7 ± 0,5 cm (likely gap). Some remarks are formulated about the influence of the spectral distribution of the neutrons flux used. (authors) [fr

  1. Characteristics of thermally reduced graphene oxide and applied for dye-sensitized solar cell counter electrode

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Ching-Yuan, E-mail: cyho@cycu.edu.tw [Department of Mechanical Engineering, Chung Yuan Christian University, Chung-Li, Taiwan (China); Department of Chemistry, Center for Nanotechnology and Institute of Biomedical Technology, Chung Yuan Christian University, Chung-Li, Taiwan (China); Wang, Hong-Wen [Department of Chemistry, Center for Nanotechnology and Institute of Biomedical Technology, Chung Yuan Christian University, Chung-Li, Taiwan (China); Department of Chemistry, Chung Yuan Christian University, Chung-Li, Taiwan (China)

    2015-12-01

    Graphical abstract: Experimental process: (1) graphite oxidized to graphene oxide; (2) thermal reduction from graphene oxide to graphene; (3) applying to DSSC counter electrode. - Highlights: • Intercalated defects were eliminated by increasing reduction temperature of GO. • High reduction temperature of tGP has lower resistance, high the electron lifetime. • Higher thermal reduction of GO proposes electrocatalytic properties. • DSSC using tGP{sub 250} as counter electrode has energy conversion efficiency of 3.4%. - Abstract: Graphene oxide (GO) was synthesized from a flake-type of graphite powder, which was then reduced to a few layers of graphene sheets using the thermal reduction method. The surface morphology, phase crystallization, and defect states of the reduced graphene were determined from an electron microscope equipped with an energy dispersion spectrometer, X-ray diffraction, Raman spectroscopy, and infrared spectra. After graphene formation, the intercalated defects that existed in the GO were removed, and it became crystalline by observing impurity changes and d-spacing. Dye-sensitized solar cells, using reduced graphene as the counter electrode, were fabricated to evaluate the electrolyte activity and charge transport performance. The electrochemical impedance spectra showed that increasing the thermal reduction temperature could achieve faster electron transport and longer electron lifetime, and result in an energy conversion efficiency of approximately 3.4%. Compared to the Pt counter electrode, the low cost of the thermal reduction method suggests that graphene will enjoy a wide range of potential applications in the field of electronic devices.

  2. Characteristics of thermally reduced graphene oxide and applied for dye-sensitized solar cell counter electrode

    International Nuclear Information System (INIS)

    Ho, Ching-Yuan; Wang, Hong-Wen

    2015-01-01

    Graphical abstract: Experimental process: (1) graphite oxidized to graphene oxide; (2) thermal reduction from graphene oxide to graphene; (3) applying to DSSC counter electrode. - Highlights: • Intercalated defects were eliminated by increasing reduction temperature of GO. • High reduction temperature of tGP has lower resistance, high the electron lifetime. • Higher thermal reduction of GO proposes electrocatalytic properties. • DSSC using tGP 250 as counter electrode has energy conversion efficiency of 3.4%. - Abstract: Graphene oxide (GO) was synthesized from a flake-type of graphite powder, which was then reduced to a few layers of graphene sheets using the thermal reduction method. The surface morphology, phase crystallization, and defect states of the reduced graphene were determined from an electron microscope equipped with an energy dispersion spectrometer, X-ray diffraction, Raman spectroscopy, and infrared spectra. After graphene formation, the intercalated defects that existed in the GO were removed, and it became crystalline by observing impurity changes and d-spacing. Dye-sensitized solar cells, using reduced graphene as the counter electrode, were fabricated to evaluate the electrolyte activity and charge transport performance. The electrochemical impedance spectra showed that increasing the thermal reduction temperature could achieve faster electron transport and longer electron lifetime, and result in an energy conversion efficiency of approximately 3.4%. Compared to the Pt counter electrode, the low cost of the thermal reduction method suggests that graphene will enjoy a wide range of potential applications in the field of electronic devices.

  3. Gas-generated thermal oxidation of a coordination cluster for an anion-doped mesoporous metal oxide.

    Science.gov (United States)

    Hirai, Kenji; Isobe, Shigehito; Sada, Kazuki

    2015-12-18

    Central in material design of metal oxides is the increase of surface area and control of intrinsic electronic and optical properties, because of potential applications for energy storage, photocatalysis and photovoltaics. Here, we disclose a facile method, inspired by geochemical process, which gives rise to mesoporous anion-doped metal oxides. As a model system, we demonstrate that simple calcination of a multinuclear coordination cluster results in synchronic chemical reactions: thermal oxidation of Ti8O10(4-aminobenzoate)12 and generation of gases including amino-group fragments. The gas generation during the thermal oxidation of Ti8O10(4-aminobenzoate)12 creates mesoporosity in TiO2. Concurrently, nitrogen atoms contained in the gases are doped into TiO2, thus leading to the formation of mesoporous N-doped TiO2. The mesoporous N-doped TiO2 can be easily synthesized by calcination of the multinuclear coordination cluster, but shows better photocatalytic activity than the one prepared by a conventional sol-gel method. Owing to an intrinsic designability of coordination compounds, this facile synthetic will be applicable to a wide range of metal oxides and anion dopants.

  4. Thermal oxidative degradation kinetics of agricultural residues using distributed activation energy model and global kinetic model.

    Science.gov (United States)

    Ren, Xiu'e; Chen, Jianbiao; Li, Gang; Wang, Yanhong; Lang, Xuemei; Fan, Shuanshi

    2018-08-01

    The study concerned the thermal oxidative degradation kinetics of agricultural residues, peanut shell (PS) and sunflower shell (SS). The thermal behaviors were evaluated via thermogravimetric analysis and the kinetic parameters were determined by using distributed activation energy model (DAEM) and global kinetic model (GKM). Results showed that thermal oxidative decomposition of two samples processed in three zones; the ignition, burnout, and comprehensive combustibility between two agricultural residues were of great difference; and the combustion performance could be improved by boosting heating rate. The activation energy ranges calculated by the DAEM for the thermal oxidative degradation of PS and SS were 88.94-145.30 kJ mol -1 and 94.86-169.18 kJ mol -1 , respectively. The activation energy obtained by the GKM for the oxidative decomposition of hemicellulose and cellulose was obviously lower than that for the lignin oxidation at identical heating rate. To some degree, the determined kinetic parameters could acceptably simulate experimental data. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. Microstructure of oxides in thermal barrier coatings grown under dry/humid atmosphere

    International Nuclear Information System (INIS)

    Zhou Zhaohui; Guo Hongbo; Wang Juan; Abbas, Musharaf; Gong Shengkai

    2011-01-01

    Graphical abstract: The presence of water vapor promoted the formation of spinels in the TBC. Highlights: → Thermal barrier coatings are produced by electron beam physical vapour deposition. → Oxidation behaviour of the coatings at 1100 deg. C has been investigated in dry/humid O 2 . → Thermally grown oxides formed in the coatings are characterized. → The presence of water vapour promotes the formation of spinel in the TBCs. - Abstract: The microstructure of thermally grown oxide (TGO) in thermal barrier coatings (TBCs) oxidized under dry/humid atmosphere at 1100 deg. C has been characterized by transmission electron microscopy. A thin and continuous oxide layer is formed in the as-deposited TBCs produced by electron beam physical vapor deposition. The TGO formed in dry atmosphere consists of an outer layer of fine α-alumina, zirconia grains and an inner layer of columnar α-alumina grains. However, a small amount of spinel is observed in the TGO under humid atmosphere. The presence of water vapour promotes the formation of spinel.

  6. Potential Health Implications of the Consumption of Thermally-Oxidized Cooking Oils – a Review

    Directory of Open Access Journals (Sweden)

    Falade Ayodeji Osmund

    2017-06-01

    Full Text Available Cooking oils are an integral part of a human diet as they are used in almost all types of culinary practices. They serve as sources of lipids with a significant nutritive value and health benefits which can be attributed to their fatty acid compositions and biological antioxidants. However, cooking oils are usually subjected to thermal oxidation which occurs when fresh cooking oil is heated at high temperatures during various food preparations. Repeated use of cooking oils in the commercial food industry is also common to maximize profit. Thermal oxidation of edible oils had since attracted great attention of nutritionist and researchers given the deteriorative effect such as generation of very cytotoxic compounds, loss of carotenoid, phenolics and vitamins thus reducing the overall antioxidant properties of the oils. Furthermore, several in vivo studies had suggested that consumption of thermally-oxidized cooking oils might not be healthy as it might negatively influence the lipid profile (increased low density lipoprotein (LDL, decreased high density lipoprotein (HDL and elevated cholesterol level, haematological system (alteration in concentration of heamoglobin (Hb, packed cell volume (PCV, white blood cell (WBC count, neutrophil and lymphocyte counts, kidney function, and induce lipid peroxidation and oxidative stress which have been associated with the pathogenesis of various degenerative diseases. Therefore, thermal oxidation seems not to provide any health benefit, as it deteriorates cooking oils and the consumption of the oils may predispose consumers to various disease conditions that may ensue from free radical generation, thereby having deleterious effect on human health.

  7. High aspect ratio silicon nanomoulds for UV embossing fabricated by directional thermal oxidation using an oxidation mask

    International Nuclear Information System (INIS)

    Chen, L Q; Chan-Park, Mary B; Yan, Y H; Zhang Qing; Li, C M; Zhang Jun

    2007-01-01

    Nanomoulding is simple and economical but moulds with nanoscale features are usually prohibitively expensive to fabricate because nanolithographic techniques are mostly serial and time-consuming for large-area patterning. This paper describes a novel, simple and inexpensive parallel technique for fabricating nanoscale pattern moulds by silicon etching followed by thermal oxidation. The mask pattern can be made by direct photolithography or photolithography followed by metal overetching for submicron- and nanoscale features, respectively. To successfully make nanoscale channels having a post-oxidation cross-sectional shape similar to that of the original channel, an oxidation mask to promote unidirectional (specifically horizontal) oxide growth is found to be essential. A silicon nitride or metal mask layer prevents vertical oxidation of the Si directly beneath it. Without this mask, rectangular channels become smaller but are V-shaped after oxidation. By controlling the silicon etch depth and oxidation time, moulds with high aspect ratio channels having widths ranging from 500 to 50 nm and smaller can be obtained. The nanomould, when passivated with a Teflon-like layer, can be used for first-generation replication using ultraviolet (UV) nanoembossing and second-generation replication in other materials, such as polydimethylsiloxane (PDMS). The PDMS stamp, which was subsequently coated with Au, was used for transfer printing of Au electrodes with a 600 nm gap which will find applications in plastics nanoelectronics

  8. Thermal oxidation of Zr–Cu–Al–Ni amorphous metal thin films

    International Nuclear Information System (INIS)

    Oleksak, R.P.; Hostetler, E.B.; Flynn, B.T.; McGlone, J.M.; Landau, N.P.; Wager, J.F.; Stickle, W.F.; Herman, G.S.

    2015-01-01

    The initial stages of thermal oxidation for Zr–Cu–Al–Ni amorphous metal thin films were investigated using X-ray photoelectron spectroscopy, transmission electron microscopy and energy dispersive X-ray spectroscopy. The as-deposited films had oxygen incorporated during sputter deposition, which helped to stabilize the amorphous phase. After annealing in air at 300 °C for short times (5 min) this oxygen was found to segregate to the surface or buried interface. Annealing at 300 °C for longer times leads to significant composition variation in both vertical and lateral directions, and formation of a surface oxide layer that consists primarily of Zr and Al oxides. Surface oxide formation was initially limited by back-diffusion of Cu and Ni ( 30 min). The oxidation properties are largely consistent with previous observations of Zr–Cu–Al–Ni metallic glasses, however some discrepancies were observed which could be explained by the unique sample geometry of the amorphous metal thin films. - Highlights: • Thermal oxidation of amorphous Zr–Cu–Al–Ni thin films was investigated. • Significant short-range inhomogeneities were observed in the amorphous films. • An accumulation of Cu and Ni occurs at the oxide/metal interface. • Diffusion of Zr was found to limit oxide film growth.

  9. Open-source micro-tensile testers via additive manufacturing for the mechanical characterization of thin films and papers.

    Science.gov (United States)

    Nandy, Krishanu; Collinson, David W; Scheftic, Charlie M; Brinson, L Catherine

    2018-01-01

    The cost of specialized scientific equipment can be high and with limited funding resources, researchers and students are often unable to access or purchase the ideal equipment for their projects. In the fields of materials science and mechanical engineering, fundamental equipment such as tensile testing devices can cost tens to hundreds of thousands of dollars. While a research lab often has access to a large-scale testing machine suitable for conventional samples, loading devices for meso- and micro-scale samples for in-situ testing with the myriad of microscopy tools are often hard to source and cost prohibitive. Open-source software has allowed for great strides in the reduction of costs associated with software development and open-source hardware and additive manufacturing have the potential to similarly reduce the costs of scientific equipment and increase the accessibility of scientific research. To investigate the feasibility of open-source hardware, a micro-tensile tester was designed with a freely accessible computer-aided design package and manufactured with a desktop 3D-printer and off-the-shelf components. To our knowledge this is one of the first demonstrations of a tensile tester with additively manufactured components for scientific research. The capabilities of the tensile tester were demonstrated by investigating the mechanical properties of Graphene Oxide (GO) paper and thin films. A 3D printed tensile tester was successfully used in conjunction with an atomic force microscope to provide one of the first quantitative measurements of GO thin film buckling under compression. The tensile tester was also used in conjunction with an atomic force microscope to observe the change in surface topology of a GO paper in response to increasing tensile strain. No significant change in surface topology was observed in contrast to prior hypotheses from the literature. Based on this result obtained with the new open source tensile stage we propose an

  10. Open-source micro-tensile testers via additive manufacturing for the mechanical characterization of thin films and papers.

    Directory of Open Access Journals (Sweden)

    Krishanu Nandy

    Full Text Available The cost of specialized scientific equipment can be high and with limited funding resources, researchers and students are often unable to access or purchase the ideal equipment for their projects. In the fields of materials science and mechanical engineering, fundamental equipment such as tensile testing devices can cost tens to hundreds of thousands of dollars. While a research lab often has access to a large-scale testing machine suitable for conventional samples, loading devices for meso- and micro-scale samples for in-situ testing with the myriad of microscopy tools are often hard to source and cost prohibitive. Open-source software has allowed for great strides in the reduction of costs associated with software development and open-source hardware and additive manufacturing have the potential to similarly reduce the costs of scientific equipment and increase the accessibility of scientific research. To investigate the feasibility of open-source hardware, a micro-tensile tester was designed with a freely accessible computer-aided design package and manufactured with a desktop 3D-printer and off-the-shelf components. To our knowledge this is one of the first demonstrations of a tensile tester with additively manufactured components for scientific research. The capabilities of the tensile tester were demonstrated by investigating the mechanical properties of Graphene Oxide (GO paper and thin films. A 3D printed tensile tester was successfully used in conjunction with an atomic force microscope to provide one of the first quantitative measurements of GO thin film buckling under compression. The tensile tester was also used in conjunction with an atomic force microscope to observe the change in surface topology of a GO paper in response to increasing tensile strain. No significant change in surface topology was observed in contrast to prior hypotheses from the literature. Based on this result obtained with the new open source tensile stage we

  11. Thermal Recycling of Waelz Oxide Using Concentrated Solar Energy

    Science.gov (United States)

    Tzouganatos, N.; Matter, R.; Wieckert, C.; Antrekowitsch, J.; Gamroth, M.; Steinfeld, A.

    2013-12-01

    The dominating Zn recycling process is the so-called Waelz process. Waelz oxide (WOX), containing 55-65% Zn in oxidic form, is mainly derived from electric arc furnace dust produced during recycling of galvanized steel. After its wash treatment to separate off chlorides, WOX is used as feedstock along with ZnS concentrates for the electrolytic production of high-grade zinc. Novel and environmentally cleaner routes for the purification of WOX and the production of Zn are investigated using concentrated solar energy as the source of high-temperature process heat. The solar-driven clinkering of WOX and its carbothermal reduction were experimentally demonstrated using a 10 kWth packed-bed solar reactor. Solar clinkering at above 1265°C reduced the amount of impurities below 0.1 wt.%. Solar carbothermal reduction using biocharcoal as reducing agent in the 1170-1320°C range yielded 90 wt.% Zn.

  12. Graphene oxide immobilized enzymes show high thermal and solvent stability

    Czech Academy of Sciences Publication Activity Database

    Hermanová, S.; Zarevúcka, Marie; Bouša, D.; Pumera, M.; Sofer, Z.

    2015-01-01

    Roč. 7, č. 13 (2015), s. 5852-5858 ISSN 2040-3364 R&D Projects: GA ČR(CZ) GA15-09001S Grant - others:GA AV ČR(CZ) M200551203 Institutional support: RVO:61388963 Keywords : graphene oxide * lipase * immobilization Subject RIV: CC - Organic Chemistry Impact factor: 7.760, year: 2015 http://pubs.rsc.org/en/content/articlepdf/2015/nr/c5nr00438a

  13. Thermal oxidation of seeds for the hydrothermal growth of WO3 nanorods on ITO glass substrate

    International Nuclear Information System (INIS)

    Ng, Chai Yan; Abdul Razak, Khairunisak; Lockman, Zainovia

    2015-01-01

    This work reports a simple seed formation method for the hydrothermal growth of tungsten oxide (WO 3 ) nanorods. A WO 3 seed layer was prepared by thermal oxidation, where a W-sputtered substrate was heated and oxidized in a furnace. Oxidation temperatures and periods were varied at 400–550 °C and 5–60 min, respectively, to determine an appropriate seed layer for nanorod growth. Thermal oxidation at 500 °C for 15 min was found to produce a seed layer with sufficient crystallinity and good adhesion to the substrate. These properties prevented the seed from peeling off during the hydrothermal process, thereby allowing nanorod growth on the seed. The nanorod film showed better electrochromic behavior (higher current density of − 1.11 and + 0.65 mA cm −2 ) than compact film (lower current density of − 0.54 and + 0.28 mA cm −2 ). - Highlights: • A simple seed formation method (thermal oxidation) on sputtered W film is reported. • Crystalline seed with good adhesion to substrate is required for nanorod growth. • The appropriate temperature and period for seed formation were 500 °C and 15 min. • WO 3 nanorods exhibited higher electrochromic current density than WO 3 compact film.

  14. Improved thermal stability and oxidation resistance of Al–Ti–N coating by Si addition

    International Nuclear Information System (INIS)

    Chen, Li; Yang, Bing; Xu, Yuxiang; Pei, Fei; Zhou, Liangcai; Du, Yong

    2014-01-01

    Addition of Si is very effective in upgrading the machining performance and thermal properties of Al–Ti–N coating. Here, we concentrate on the thermal stability and oxidation resistance of Al–Ti–Si–N coating. Alloying with Si favors the growth of wurtzite phase, and thereby causes a drop in hardness from ∼ 34.5 to 28.7 GPa. However, Si-containing coating retards the formation of w-AlN during thermal annealing, and thereby behaves a high hardness value of ∼ 31.3 GPa after annealing at T a = 1100 °C. After 10 h exposure in air at 850 °C, Al–Ti–N coating is fully oxidized. Incorporation of Si significantly improves the oxidation resistance of Al–Ti–N due to the combined effects with the promoted formation of Al-oxide rich top-scale and retarded transformation of anatase (a-) TiO 2 into rutile (r-) TiO 2 , where only ∼ 1.43 μm oxide scale is shown after oxidation at 1100 °C for 15 h. Noticeable is that the worst oxidation resistance of Al–Ti–Si–N coating in the temperature range from 800 to 1100 °C is obtained at 950 °C with oxide scale of ∼ 1.76 μm due to the fast formation of r-TiO 2 . Additionally, a pre-oxidation at 1000 °C has a positive effect on the oxidation resistance of Al–Ti–Si–N coating, which is attributed to the formation of Al-oxide rich top-scale, and thus inhibits the outward diffusion of metal atoms and inward diffusion of O. - Highlights: • Si as a substitutional solid solution and via the formation of a-Si 3 N 4 coexists. • Si addition favors the growth of wurtzite phase and causes a decreased hardness. • Alloying with Si improves the oxidation resistance of AlTiN. • AlTiSiN behaves the worst oxidation resistance at 950 °C from 800 to 1100 °C. • A pre-oxidation at 1000 °C improves the oxidation resistance of AlTiSiN coating

  15. Colour of Tester Effects on Children's Expressed Attitudes.

    Science.gov (United States)

    Thomas, K. C.

    1978-01-01

    Discusses a study of student attitudes, preferences, and stereotyping among White Britons and West Indian students in an English secondary school. Findings indicated that factors such as the race of the tester influenced the test situation. For journal availability, see SO 506 785. (DB)

  16. Software testing an ISTQB-BCS certified tester foundation guide

    CERN Document Server

    Hambling, Brian; Samaroo, Angelina; Thompson, Geoff; Williams, Peter; Hambling, Brian

    2015-01-01

    This practical guide provides insight into software testing, explaining the basics of the testing process and how to perform effective tests. It provides an overview of different techniques and how to apply them. It is the best-selling official textbook of the ISTQB-BCS Certified Tester Foundation Level.

  17. Evaluation of thermal properties of sintered beryllium oxide produced from Indian beryl ore

    International Nuclear Information System (INIS)

    Nair, Sathi R.; Ghanwat, S.J.; Patro, P.K.; Syambabu, M.; Mawal, N.E.; Mahata, T.; Sinha, P.K.

    2014-01-01

    Beryllium oxide (BeO) ceramics possess many interesting properties such as good thermal conductivity, high electrical resistivity, high chemical and thermal stability, low dielectric constant, low dielectric loss and low neutron absorption coefficient. These properties lead to its wide use in vacuum electronics technology, nuclear technology, microelectronics and photoelectron technology. The above properties depend on the purity of the material as well as density and microstructure of the sintered body. For high temperature application thermal conductivity and thermal expansion are two important parameters. In the present study, high purity fine BeO powder has been prepared by beryllate route starting with crude beryllium hydroxide. The powder has been sintered at 1550℃ and sintered samples have been evaluated for its thermal properties

  18. Modification of graphite structure by irradiation, revealed by thermal oxidation. Examination by electronic microscopy

    International Nuclear Information System (INIS)

    Rouaud, Michel

    1969-01-01

    Based on the analysis of images obtained by electronic microscopy, this document reports the comparative study of the action of neutrons on three different graphites: a natural one (Ticonderoga) and two pyrolytic ones (Carbone-Lorraine and Raytheon). The approach is based on the modification of features of thermal oxidation of graphites by dry air after irradiation. Different corrosion features are identified. The author states that there seems to be a relationship between the number and shape of these features, and defects existing on the irradiated graphite before oxidation. For low doses, the feature aspect varies with depth at which oxidation occurs. For higher doses, the aspect remains the same [fr

  19. Thermal oxidation of InP surfaces modified with NiO + PbO mixtures

    International Nuclear Information System (INIS)

    Mittova, I.Ya.; Tomina, E.V.; Samsonov, A.A.; Lukin, A.N.; Simonov, S.P.

    2005-01-01

    The oxidation kinetics of (NiO + PbO)/InP, NiO/InP and PbO/InP structures in an oxygen flow is studied in the temperature range of 400-550 deg C. It is shown by IR spectroscopy that the thermal oxidation of (NiO + PbO)/InP structures leads to the formation of nickel and lead polyphosphates and indium ortho- and metaphosphates. The nickel phosphates may then gradually transform into diphosphates, depending on the oxidation temperature, whereas the lead phosphates undergo no changes [ru

  20. The effects of Bifidobacteria on the lipid profile and oxidative stress biomarkers of male rats fed thermally oxidized soybean oil.

    Science.gov (United States)

    Awney, Hala A

    2011-08-01

    Over the years, there has been concern about the changes taking place in heated oils and the effects on individuals consuming them. The present study investigated the effects of a diet containing thermally oxidized soybean oil (TO) or TO supplemented with probiotic Bifidobacteria (TO+Pro) on the serum lipid profile and oxidative stress biomarkers of male rats. The data showed several indicators of oil deterioration after thermal processing, including high levels of % free fatty acid (FFA; 15-fold), acid value (AV; 14-fold), peroxide value (8-fold), p-anisidine value (AnV; 39-fold), total oxidation value (TOTOX; 19-fold), thiobarbituric acid-reactive substances (TBARS) value (8.5-fold), and trans-FA (TFA) isomers (2.5-fold) compared to the control. The rats that were fed a diet containing TO showed a significant (p blood serum samples. High levels of TBARS, superoxide dismutase (SOD), and glutathione reductase (GR) activities were also detected in the livers, kidneys, testes, and brains of rats. Interestingly, a diet containing TO+Pro restored all biological parameters to their control values. The present data suggested that Bifidobacteria may ameliorate the serum lipid profile and oxidative stress biomarkers that are generated in animals that are fed a TO diet.

  1. Oxidation behavior of Hf-modified platinum aluminide coatings during thermal cycling

    Directory of Open Access Journals (Sweden)

    Liya Ye

    2018-02-01

    Full Text Available Platinum aluminide coatings with different Hf contents were fabricated by using HfCl4. The oxidation kinetics and the rumpling behavior of oxide scale were investigated. After thermal cycling, the coating with 0.46 wt% Hf showed least weight gain. With the increase of Hf content, rumpling extent of the scale decreased. Meanwhile, HfO2 preferentially formed in the scale resulting in the increase of scale thickness. The oxidation of excessive Hf even caused the spallation of the scale. The results in the present study indicate that although Hf plays an important role in decreasing rumpling extent of TGO, the oxidation of Hf decreases the adhesion of the scale. Keywords: Pt-Al coating, Hf, Oxidation, Rumpling

  2. Legislative measures for suppressing emission of nitrogen oxides from thermal power stations

    Energy Technology Data Exchange (ETDEWEB)

    Kotler, V.R.

    1987-11-01

    Reviews measures taken by some countries to control emission of nitrogen oxides from thermal power stations run on solid fuels, mazout and gas. Refers to maximum permissible concentrations of nitrogen oxides in USA (100 mg/m/sup 3/), Canada (460 mg/m/sup 3/), Japan (41-62 mg/m/sup 3/) and several European countries. Discusses legislative measures in FRG (Federal Regulations BImSchG), particularly Instruction No. 13 BImSchV concerning large boilers run on solid fuels or mazout (continuous monitoring of nitrogen oxide emission into atmosphere, equipping old boilers with means of reducing nitrogen oxide emission, reduction of acid rain). Gives maximum permissible concentrations of nitrogen oxides for new boilers agreed by various countries. 5 refs.

  3. Optoelectronic properties of expanding thermal plasma deposited textured zinc oxide : effect of aluminum doping

    NARCIS (Netherlands)

    Groenen, R.; Kieft, E.R.; Linden, J.L.; Sanden, van de M.C.M.

    2006-01-01

    Aluminum-doped zinc oxide films exhibiting a rough surface morphol. are deposited on glass substrates utilizing expanding thermal plasma. Spectroscopic ellipsometry is used to evaluate optical and electronic film properties. The presence of aluminum donors in doped films is confirmed by a shift in

  4. Oil-structuring characterization of natural waxes in canola oil oleogels: Rheological, thermal, and oxidative properties

    Science.gov (United States)

    Natural waxes (candelilla wax, carnauba wax, and beeswax) were utilized as canola oil structurants to produce oleogels and their physicochemical properties were evaluated from rheological, thermal, and oxidative points of view. The oleogels with candelilla wax exhibited the highest hardness, followe...

  5. Plasma processes and film growth of expanding thermal plasma deposited textured zinc oxide

    NARCIS (Netherlands)

    Groenen, R.; Linden, J.L.; Sanden, van de M.C.M.

    2005-01-01

    Plasma processes and film growth of textured zinc oxide deposited from oxygen and diethyl zinc utilizing expanding thermal argon plasma created by a cascaded arc is discussed. In all conditions explored, an excess of argon ions and low temperature electrons is available, which represent the

  6. Influence of feeding thermally peroxidized soybean oil on oxidative status in growing pigs

    Science.gov (United States)

    The objectives of this study were to determine whether feeding thermally processed peroxidized soybean oil (SO) induces markers of oxidative stress and alters antioxidant status in pig tissue, blood, and urine. Fifty-six barrows (25.3 ± 3.3 kg initial BW) were randomly assigned to dietary treatments...

  7. Thermal radiative near field transport between vanadium dioxide and silicon oxide across the metal insulator transition

    Energy Technology Data Exchange (ETDEWEB)

    Menges, F.; Spieser, M.; Riel, H.; Gotsmann, B., E-mail: bgo@zurich.ibm.com [IBM Research-Zurich, Säumerstrasse 4, CH-8803 Rüschlikon (Switzerland); Dittberner, M. [IBM Research-Zurich, Säumerstrasse 4, CH-8803 Rüschlikon (Switzerland); Photonics Laboratory, ETH Zurich, 8093 Zurich (Switzerland); Novotny, L. [Photonics Laboratory, ETH Zurich, 8093 Zurich (Switzerland); Passarello, D.; Parkin, S. S. P. [IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120 (United States)

    2016-04-25

    The thermal radiative near field transport between vanadium dioxide and silicon oxide at submicron distances is expected to exhibit a strong dependence on the state of vanadium dioxide which undergoes a metal-insulator transition near room temperature. We report the measurement of near field thermal transport between a heated silicon oxide micro-sphere and a vanadium dioxide thin film on a titanium oxide (rutile) substrate. The temperatures of the 15 nm vanadium dioxide thin film varied to be below and above the metal-insulator-transition, and the sphere temperatures were varied in a range between 100 and 200 °C. The measurements were performed using a vacuum-based scanning thermal microscope with a cantilevered resistive thermal sensor. We observe a thermal conductivity per unit area between the sphere and the film with a distance dependence following a power law trend and a conductance contrast larger than 2 for the two different phase states of the film.

  8. Thermally stimulated iron oxide transformations and magnetic behaviour of cerium dioxide/iron oxide reactive sorbents

    Czech Academy of Sciences Publication Activity Database

    Luňáček, J.; Životský, O.; Jirásková, Yvonna; Buršík, Jiří; Janoš, P.

    2016-01-01

    Roč. 120, OCT (2016), s. 295-303 ISSN 1044-5803 R&D Projects: GA MŠk(CZ) LQ1601 Institutional support: RVO:68081723 Keywords : Oxide -nano-composites * Mössbauer spectroscopy * TEM * Cerium oxide * Magnetic parameters Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.714, year: 2016

  9. Microstructural characterization of thermal barrier coating on Inconel 617 after high temperature oxidation

    Directory of Open Access Journals (Sweden)

    Mohammadreza Daroonparvar

    2013-06-01

    Full Text Available A turbine blade was protected against high temperature corrosion and oxidation by thermal barrier coatings (TBCsusing atmospheric plasma spraying technique (APS on a Ni-based superalloy (Inconel 617. The coatings (NiCr6AlY/ YSZ and NiCr10AlY/YSZ consist of laminar structure with substantial interconnected porosity transferred oxygen from Yittria stabilized Zirconia (YSZ layer toward the bond coat (NiCrAlY. Hence, a thermally grown oxide layer (TGO was formed on the metallic bond coat and internal oxidation of the bond coat occurred during oxidation. The TBC systems were oxidized in a normal electrically heated furnace at 1150 °C for 18, 22, 26, 32 and 40h.Microstructural characterization of coatings demonstrated that the growth of the TGO layer on the nickel alloy with 6wt. % Al is more rapid than TGO with 10wt. % Al. In addition, many micro-cracks were observed at the interface of NiCr6AlY/YSZ. X-ray diffraction analysis (XRD showed the existence of detrimental oxides such as NiCr2O4, NiCrO3 and NiCrO4 in the bond coat containing 6wt. % Al, accompanied by rapid volume expansion causing the destruction of TBC. In contrast, in the bond coat with 10wt. % Al, NiO, Al2O3and Cr2O3 oxides were formed while very low volume expansion occurred. The oxygen could not penetrate into the TGO layer of bond coat with 10 wt. % Al during high temperature oxidation and the detrimental oxides were not extensively formed within the bond coat as more oxygen was needed. The YSZ with higher Al content showed higher oxidation resistance.

  10. Insulating gallium oxide layer produced by thermal oxidation of gallium-polar GaN: Insulating gallium oxide layer produced by thermal oxidation of gallium-polar GaN

    Energy Technology Data Exchange (ETDEWEB)

    Hossain, T. [Kansas State Univ., Manhattan, KS (United States); Wei, D. [Kansas State Univ., Manhattan, KS (United States); Nepal, N. [Naval Research Lab. (NRL), Washington, DC (United States); Garces, N. Y. [Naval Research Lab. (NRL), Washington, DC (United States); Hite, J. K. [Naval Research Lab. (NRL), Washington, DC (United States); Meyer, H. M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Eddy, C. R. [Naval Research Lab. (NRL), Washington, DC (United States); Baker, Troy [Nitride Solutions, Wichita, KS (United States); Mayo, Ashley [Nitride Solutions, Wichita, KS (United States); Schmitt, Jason [Nitride Solutions, Wichita, KS (United States); Edgar, J. H. [Kansas State Univ., Manhattan, KS (United States)

    2014-02-24

    We report the benefits of dry oxidation of n -GaN for the fabrication of metal-oxide-semiconductor structures. GaN thin films grown on sapphire by MOCVD were thermally oxidized for 30, 45 and 60 minutes in a pure oxygen atmosphere at 850 °C to produce thin, smooth GaOx layers. Moreover, the GaN sample oxidized for 30 minutes had the best properties. Its surface roughness (0.595 nm) as measured by atomic force microscopy (AFM) was the lowest. Capacitance-voltage measurements showed it had the best saturation in accumulation region and the sharpest transition from accumulation to depletion regions. Under gate voltage sweep, capacitance-voltage hysteresis was completely absent. The interface trap density was minimum (Dit = 2.75×1010 cm–2eV–1) for sample oxidized for 30 mins. These results demonstrate a high quality GaOx layer is beneficial for GaN MOSFETs.

  11. Measurement of thermal conductivity of the oxide coating on autoclaved monel-400

    International Nuclear Information System (INIS)

    Dua, A.K.; George, V.C.; Agarwala, R.P.

    1982-01-01

    Thermal conductivity of the oxide coating on monel-400 has been measured by a direct method. The oxide coating is applied on an electrically conducting wire having stable characteristics. The wire is placed in a constant temperature bath and a constant direct current is passed through it. The wire gets heated and loses heat to the surrounding. Temperature is measured by considering it as a resistance thermometer. A convection heat transfer coefficient, which is difficult to measure experimentally but is involved in the analytical expression for thermal conductivity, is eliminated by connecting a second uncoated wire of a noble metal having similar surface finish as that of the coated wire in series with it. The accuracy of the method is nearly six percent. However, the method is not easily applicable for very thin (thickness <= 1μ), highly porous coatings and materials having relatively large thermal conductivity. (M.G.B.)

  12. Graphene oxide-loaded shortening as an environmentally friendly heat transfer fluid with high thermal conductivity

    Directory of Open Access Journals (Sweden)

    Vongsetskul Thammasit

    2017-01-01

    Full Text Available Graphene oxide-loaded shortening (GOS, an environmentally friendly heat transfer fluid with high thermal conductivity, was successfully prepared by mixing graphene oxide (GO with a shortening. Scanning electron microscopy revealed that GO particles, prepared by the modified Hummer’s method, dispersed well in the shortening. In addition, the latent heat of GOS decreased while their viscosity and thermal conductivity increased with increasing the amount of loaded GO. The thermal conductivity of the GOS with 4% GO was higher than that of pure shortening of ca. three times, from 0.1751 to 0.6022 W/mK, and increased with increasing temperature. The GOS started to be degraded at ca. 360°C. After being heated and cooled at 100°C for 100 cycles, its viscosity slightly decreased and no chemical degradation was observed. Therefore, the prepared GOS is potentially used as environmentally friendly heat transfer fluid at high temperature.

  13. Standard Test Method for Thermal Oxidative Resistance of Carbon Fibers

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1982-01-01

    1.1 This test method covers the apparatus and procedure for the determination of the weight loss of carbon fibers, exposed to ambient hot air, as a means of characterizing their oxidative resistance. 1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to inch-pound units which are provided for information only and are not considered standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard information, see Section 8.

  14. Thermal radiation modelling in a tubular solid oxide fuel cell

    International Nuclear Information System (INIS)

    Austin, M.E.; Pharoah, J.G.; Vandersteen, J.D.J.

    2004-01-01

    Solid Oxide Fuel Cells (SOFCs) are becoming the fuel cell of choice among companies and research groups interested in small power generation units. Questions still exist, however, about the operating characteristics of these devices; in particular the temperature distribution in the fuel cell. Using computational fluid dynamics (CFD) a model is proposed that incorporates conduction, convection and radiation. Both surface-to-surface and participating media are considered. It is hoped that a more accurate account of the temperature field in the various flow channels and cell components will be made to assist work on design of fuel cell components and reaction mechanisms. The model, when incorporating radiative heat transfer with participating media, predicts substantially lower operating temperatures and smaller temperature gradients than it does without these equations. It also shows the importance of the cathode air channel in cell cooling. (author)

  15. A highly sensitive and durable electrical sensor for liquid ethanol using thermally-oxidized mesoporous silicon

    Science.gov (United States)

    Harraz, Farid A.; Ismail, Adel A.; Al-Sayari, S. A.; Al-Hajry, A.; Al-Assiri, M. S.

    2016-12-01

    A capacitive detection of liquid ethanol using reactive, thermally oxidized films constructed from electrochemically synthesized porous silicon (PSi) is demonstrated. The sensor elements are fabricated as meso-PSi (pore sizes hydrophobic PSi surface exhibited almost a half sensitivity of the thermal oxide sensor. The response to water is achieved only at the oxidized surface and found to be ∼one quarter of the ethanol sensitivity, dependent on parameters such as vapor pressure and surface tension. The capacitance response retains ∼92% of its initial value after continuous nine cyclic runs and the sensors presumably keep long-term stability after three weeks storage, demonstrating excellent durability and storage stability. The observed behavior in current system is likely explained by the interface interaction due to dipole moment effect. The results suggest that the current sensor structure and design can be easily made to produce notably higher sensitivities for reversible detection of various analytes.

  16. Consumption of thermally oxidized palm oil diets alters biochemical indices in rats

    Directory of Open Access Journals (Sweden)

    Ayodeji Osmund Falade

    2015-06-01

    Full Text Available Palm oil is thermally oxidized to increase its palatability and this has been a usual practice in most homes. This study sought to assess the biochemical responses of rats to thermally oxidized palm oil diets. Therefore, Wistar strain albino rats (Rattus norveigicus were fed with fresh palm oil (control and thermally oxidized palm oil (test groups diets and water ad libitum for 30 days. Then, the malondialdehyde (MDA contents and total protein of the plasma and liver were determined. Subsequently, the plasma liver function markers [alanine transaminase (ALT, aspartate transaminase (AST, alkaline phosphatase (ALP, albumin (ALB and total bilirubin (TBIL ] and the lipid profile [triglyceride (TRIG, total cholesterol (T-CHOL, high density lipoprotein (HDL-CHOL and low density lipoprotein (LDL-CHOL ] were assayed. The results of the study revealed that there was a significant decrease (P < 0.05 in the plasma and liver total protein, ALB, TRIG and HDL-CHOL of the test groups when compared with the control. Conversely, there was a significant increase (P < 0.05 in the activities of ALT, AST and ALP, TBIL, T-CHOL, LDL-CHOL and plasma/liver MDA of the test groups when compared with the control. These effects were most pronounced in rats fed with 20 min-thermally oxidized palm oil diet. Hence, consumption of thermally oxidized palm oil diets had deleterious effects on biochemical indices in rats. Therefore, cooking with and/or consumption of palm oil subjected to heat treatment for several long periods of time should be discouraged in our homes as this might have deleterious effects on human health.

  17. Thermal durability of OPC pastes admixed with nano iron oxide

    Directory of Open Access Journals (Sweden)

    Ahmed A. Amer

    2015-08-01

    Full Text Available Nanotechnology helps in producing materials with prospective properties, for each field of science (physics, chemistry, bio-science as well as construction materials. Nanoparticles belong to the materials in the field of civil engineering which have a high surface area to provide high chemical reactivity. Some researchers have employed nanoparticles into cementitious materials based on ordinary Portland cement to modify the properties of this system. They have important advantages for the hydration and microstructure of cement paste to increase the rate of hydration and the amount of formed CSH gel. The aim of this work is to investigate the influence of NF on the fire resistance of OPC pastes. The NF was synthesized by thermal decomposition of basic ferric acetate fired at 275, 600 and 800 °C. The crystal size of the prepared NF as previously determined was 14.6, 16.98 and 18.68 nm, respectively. OPC admixed with 1 wt% NF prepared at 275 °C gives the higher fire resistance than those admixed with 2 or 3 wt%. It shows the higher bulk density, compressive strength and lower porosity up to 450 °C than the blank OPC. As the firing temperature of NF increases the fire resistance diminishes.

  18. Calcium incorporation in graphene oxide particles: A morphological, chemical, electrical, and thermal study

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Kelly L.S. [Instituto Nacional de Metrologia, Qualidade e Tecnologia, Av. Nossa Sra. das Graças, 50, 25250-020 Duque de Caxias (Brazil); Instituto de Química, Universidade Federal do Rio de Janeiro, Av. Athos da Silveira Ramos, 149, 21941-909 Rio de Janeiro (Brazil); Curti, Raphael V.; Araujo, Joyce R.; Landi, Sandra M.; Ferreira, Erlon H.M.; Neves, Rodrigo S.; Kuznetsov, Alexei; Sena, Lidia A. [Instituto Nacional de Metrologia, Qualidade e Tecnologia, Av. Nossa Sra. das Graças, 50, 25250-020 Duque de Caxias (Brazil); Archanjo, Braulio S., E-mail: bsarchanjo@inmetro.gov.br [Instituto Nacional de Metrologia, Qualidade e Tecnologia, Av. Nossa Sra. das Graças, 50, 25250-020 Duque de Caxias (Brazil); Achete, Carlos A. [Instituto Nacional de Metrologia, Qualidade e Tecnologia, Av. Nossa Sra. das Graças, 50, 25250-020 Duque de Caxias (Brazil); Departamento de Engenharia Metalúrgica e de Materiais, Universidade Federal do Rio de Janeiro, 21941-972 Rio de Janeiro (Brazil)

    2016-07-01

    Surface chemical modification and functionalization are common strategies used to provide new properties or functionalities to a material or to enhance existing ones. In this work, graphene oxide prepared using Hummers' method has been chemically modified with calcium ions by immersion in a calcium carbonate solution. Transmission electron microscopy analyses showed that graphene oxide (GO) and calcium incorporated graphene oxide have a morphology similar to an ultra-thin membrane composed of overlapping sheets. X-ray diffraction and Fourier-infrared spectroscopy show that calcium carbonate residue was completely removed by hydrochloric acid washes. Energy dispersive X-ray spectroscopy mapping showed spatially homogeneous calcium in Ca-incorporated graphene oxide sample after HCl washing. This Ca is mainly ionic according to X-ray photoelectron spectroscopy, and its incorporation promoted a small reduction in the graphene oxide structure, corroborated also by four-point probe measurements. A thermal study shows a remarkable increase in the GO stability with the presence of Ca{sup 2+} ions. - Highlights: • Graphene oxide has been chemically modified with Ca ions by immersion in a CaCO{sub 3} solution. • GO–Ca has morphology similar to an ultra-thin membrane composed of overlapping sheets. • CaCO{sub 3} residue was completely removed by acid washes, leaving only ionic calcium. • EDS maps show that Ca incorporation is spatially homogeneous in GO structure. • Thermal analyses show a remarkable increase in GO stability after Ca incorporation.

  19. Calcium incorporation in graphene oxide particles: A morphological, chemical, electrical, and thermal study

    International Nuclear Information System (INIS)

    Castro, Kelly L.S.; Curti, Raphael V.; Araujo, Joyce R.; Landi, Sandra M.; Ferreira, Erlon H.M.; Neves, Rodrigo S.; Kuznetsov, Alexei; Sena, Lidia A.; Archanjo, Braulio S.; Achete, Carlos A.

    2016-01-01

    Surface chemical modification and functionalization are common strategies used to provide new properties or functionalities to a material or to enhance existing ones. In this work, graphene oxide prepared using Hummers' method has been chemically modified with calcium ions by immersion in a calcium carbonate solution. Transmission electron microscopy analyses showed that graphene oxide (GO) and calcium incorporated graphene oxide have a morphology similar to an ultra-thin membrane composed of overlapping sheets. X-ray diffraction and Fourier-infrared spectroscopy show that calcium carbonate residue was completely removed by hydrochloric acid washes. Energy dispersive X-ray spectroscopy mapping showed spatially homogeneous calcium in Ca-incorporated graphene oxide sample after HCl washing. This Ca is mainly ionic according to X-ray photoelectron spectroscopy, and its incorporation promoted a small reduction in the graphene oxide structure, corroborated also by four-point probe measurements. A thermal study shows a remarkable increase in the GO stability with the presence of Ca"2"+ ions. - Highlights: • Graphene oxide has been chemically modified with Ca ions by immersion in a CaCO_3 solution. • GO–Ca has morphology similar to an ultra-thin membrane composed of overlapping sheets. • CaCO_3 residue was completely removed by acid washes, leaving only ionic calcium. • EDS maps show that Ca incorporation is spatially homogeneous in GO structure. • Thermal analyses show a remarkable increase in GO stability after Ca incorporation.

  20. Changes in physical properties of graphene oxide with thermal reduction

    Science.gov (United States)

    Pandit, Bhishma; Jo, Chang Hee; Joo, Kwan Seon; Cho, Jaehee

    2017-08-01

    Reduced graphene oxide (rGO) has attracted significant attention as an easily fabricable twodimensional material. Depending on the oxygen-containing functional groups (OFGs) in an rGO specimen, the optical and electrical properties can vary significantly, directly affecting the performance of devices in which rGO is implemented. Here, we investigated the optical and electrical properties of GO treated with various annealing (reduction) temperatures from 350 to 950 °C in H2 ambient. Using diverse characteristic tools, we found that the transmittance, nanoscale domain size, OFGs in GO and rGO, and Schottky barrier height (SBH) measured on n-type GaN are significantly influenced by the annealing temperature. The relative intensity of the defect-induced band in Raman spectroscopy showed a minimum at the annealing temperature of approximately 350 °C, before the OFGs in rGO showed vigorous changes in relative content. When the domain size of rGO reached a minimum at the annealing temperature of 650 °C, the SBH of rGO/GaN showed the maximum value of 1.07 eV.

  1. Changes in Physical Properties of Graphene Oxide with Thermal Reduction

    Energy Technology Data Exchange (ETDEWEB)

    Pandit, Bhishma; Jo, Chang Hee; Joo, Kwan Seon; Cho, Jaehee [Chonbuk National University, Jeonju (Korea, Republic of)

    2017-08-15

    Reduced graphene oxide (rGO) has attracted significant attention as an easily fabricable two dimensional material. Depending on the oxygen-containing functional groups (OFGs) in an rGO specimen, the optical and electrical properties can vary significantly, directly affecting the performance of devices in which rGO is implemented. Here, we investigated the optical and electrical properties of GO treated with various annealing (reduction) temperatures from 350 to 950 ℃ in H2 ambient. Using diverse characteristic tools, we found that the transmittance, nanoscale domain size, OFGs in GO and rGO, and Schottky barrier height (SBH) measured on n-type GaN are significantly influenced by the annealing temperature. The relative intensity of the defect-induced band in Raman spectroscopy showed a minimum at the annealing temperature of approximately 350 ℃, before the OFGs in rGO showed vigorous changes in relative content. When the domain size of rGO reached a minimum at the annealing temperature of 650 ℃, the SBH of rGO/GaN showed the maximum value of 1.07 eV.

  2. Uranium dioxide and beryllium oxide enhanced thermal conductivity nuclear fuel development

    International Nuclear Information System (INIS)

    Andrade, Antonio Santos; Ferreira, Ricardo Alberto Neto

    2007-01-01

    The uranium dioxide is the most used substance as nuclear reactor fuel for presenting many advantages such as: high stability even when it is in contact with water in high temperatures, high fusion point, and high capacity to retain fission products. The conventional fuel is made with ceramic sintered pellets of uranium dioxide stacked inside fuel rods, and presents disadvantages because its low thermal conductivity causes large and dangerous temperature gradients. Besides, the thermal conductivity decreases further as the fuel burns, what limits a pellet operational lifetime. This research developed a new kind of fuel pellets fabricated with uranium dioxide kernels and beryllium oxide filling the empty spaces between them. This fuel has a great advantage because of its higher thermal conductivity in relation to the conventional fuel. Pellets of this kind were produced, and had their thermophysical properties measured by the flash laser method, to compare with the thermal conductivity of the conventional uranium dioxide nuclear fuel. (author) (author)

  3. Thermal bubble inkjet printing of water-based graphene oxide and graphene inks on heated substrate

    Science.gov (United States)

    Huang, Simin; Shen, Ruoxi; Qian, Bo; Li, Lingying; Wang, Wenhao; Lin, Guanghui; Zhang, Xiaofei; Li, Peng; Xie, Yonglin

    2018-04-01

    Stable-jetting water-based graphene oxide (GO) and graphene (GR) inks without any surfactant or stabilizer are prepared from an unstable-jetting water-based starting solvent, with many thermal bubble inkjet satellite drops, by simply increasing the material concentration. The concentration-dependent thermal bubble inkjet droplet generation process is studied in detail. To overcome the low concentration properties of water-based thermal bubble inkjet inks, the substrate temperature is tuned below 60 °C to achieve high-quality print lines. Due to the difference in hydrophilicity and hydrophobicity of the 2D materials, the printed GO lines show a different forming mechanism from that of the GR lines. The printed GO lines are reduced by thermal annealing and by ascorbic acid, respectively. The reduced GO lines exhibit electrical conductivity of the same order of magnitude as that of the GR lines.

  4. Growth Stresses in Thermally Grown Oxides on Nickel-Based Single-Crystal Alloys

    Science.gov (United States)

    Rettberg, Luke H.; Laux, Britta; He, Ming Y.; Hovis, David; Heuer, Arthur H.; Pollock, Tresa M.

    2016-03-01

    Growth stresses that develop in α-Al2O3 scale that form during isothermal oxidation of three Ni-based single crystal alloys have been studied to elucidate their role in coating and substrate degradation at elevated temperatures. Piezospectroscopy measurements at room temperature indicate large room temperature compressive stresses in the oxides formed at 1255 K or 1366 K (982 °C or 1093 °C) on the alloys, ranging from a high of 4.8 GPa for René N4 at 1366 K (1093 °C) to a low of 3.8 GPa for René N5 at 1255 K (982 °C). Finite element modeling of each of these systems to account for differences in coefficients of thermal expansion of the oxide and substrate indicates growth strains in the range from 0.21 to 0.44 pct at the oxidation temperature, which is an order of magnitude higher than the growth strains measured in the oxides on intermetallic coatings that are typically applied to these superalloys. The magnitudes of the growth strains do not scale with the parabolic oxidation rate constants measured for the alloys. Significant spatial inhomogeneities in the growth stresses were observed, due to (i) the presence of dendritic segregation and (ii) large carbides in the material that locally disrupts the structure of the oxide scale. The implications of these observations for failure during cyclic oxidation, fatigue cycling, and alloy design are considered.

  5. The disclosed transformation of pre-sputtered Ti films into nanoparticles via controlled thermal oxidation

    Science.gov (United States)

    Awad, M. A.; Raaif, M.

    2018-05-01

    Nanoparticles of TiO2 were successfully prepared from pre-sputtered Ti films using the controlled thermal oxidation. The effect of oxidation temperature on structural, morphological and optical properties in addition to photocatalysis activity of the sputtered films was tested and explained. Analysis of XRD and EDAX elucidated the enhancement in crystallization and oxygen content with the increase of oxidation temperature. SEM depicted the formation of very fine nanoparticles with no specific border on the films oxidized at 550 and 600 °C, whilst crystallites with larger size of approximately from 16 to 23 nm have been observed for the film oxidized at 650 °C. Both optical transmission and refractive index were increased with increasing the oxidation temperature. A red shift in the absorption edge was obtained for the films oxidized at 650 °C compared to that oxidized at 600 °C. The photocatalysis tests demonstrated the priority of 600 °C nanoparticle films to decompose methyl orange (MO) more than 650 °C treated film.

  6. Effects of X irradiation and high field electron injection of the electrical properties of rapid thermal oxides

    International Nuclear Information System (INIS)

    Schubert, W.K.; Seager, C.H.

    1988-01-01

    Rapid thermal oxidation (RTO) is a promising tool for fabricating the thin gate oxides (5 to 15 nm) that will be needed in future submicron integrated circuits, because of its inherently superior time-temperature control when compared to conventional oxidation methods. It is important to demonstrate that RTO can be used without adversely affecting the radiation hardness or high field properties of the oxide. Beyond this demonstration, rapid thermal processing makes it possible to determine more precisely how the kinetics of oxidation and post oxidation annealing affect the device properties. Information of this type should prove useful in modeling relevant defect formation mechanisms. The present paper is part of a systematic study of the effect of rapid thermal processing on the radiation and high field response of thin oxides

  7. Physical and electrical properties of thermal oxidized Sm{sub 2}O{sub 3} gate oxide thin film on Si substrate: Influence of oxidation durations

    Energy Technology Data Exchange (ETDEWEB)

    Goh, Kian Heng; Haseeb, A.S.M.A.; Wong, Yew Hoong, E-mail: yhwong@um.edu.my

    2016-05-01

    Growth of 150 nm Sm{sub 2}O{sub 3} films by sputtered pure samarium metal film on silicon substrates and followed by thermal oxidation process in oxygen ambient at 700 °C through various oxidation durations (5 min, 10 min, 15 min and 20 min) has been carried out. The crystallinity of Sm{sub 2}O{sub 3} film and existence of interfacial layer have been evaluated by X-ray diffraction, Fourier transform infrared and Raman analysis. Crystallite size and microstrain of Sm{sub 2}O{sub 3} were estimated by Williamson–Hall plot analysis. Calculated crystallite size of Sm{sub 2}O{sub 3} from Scherrer equation has similar trend with the value from Williamson–Hall plot. The presence of interfacial layer is supported by composition line scan by energy dispersive X-ray spectroscopy analysis. The surface roughness and surface topography of Sm{sub 2}O{sub 3} film were examined by atomic force microscopy analysis. The electrical characterization revealed that 15 min of oxidation durations with smoothest surface has highest breakdown voltage, lowest leakage current density and highest barrier height value. - Highlights: • Thermal oxidation of sputtered pure metallic Sm in oxygen ambient • Formation of polycrystalline Sm{sub 2}O{sub 3} and semi-polycrystalline interfacial layers • Optimization of oxidation duration of pure metallic Sm in oxygen ambient • Enhanced electrical performance with smooth surface and increased barrier height.

  8. Thermal-grating contributions to degenerate four-wave mixing in nitric oxide

    International Nuclear Information System (INIS)

    Danehy, P.M.; Paul, P.H.; Farrow, R.L.

    1995-01-01

    We report investigations of degenerate four-wave mixing (DFWM) line intensities in the A 2 Σ + left-arrow X 2 Π electronic transitions of nitric oxide. Contributions from population gratings (spatially varying perturbations in the level populations of absorbing species) and thermal gratings (spatially varying perturbations in the overall density) were distinguished and compared by several experimental and analytical techniques. For small quantities of nitric oxide in a strongly quenching buffer gas (carbon dioxide), we found that thermal-grating contributions dominated at room temperature for gas pressures of ∼0.5 atm and higher. In a nearly nonquenching buffer (nitrogen) the population-grating mechanism dominated at pressures of ∼1.0 atm and lower. At higher temperatures in an atmospheric-pressure methane/air flame, population gratings of nitric oxide also dominated. We propose a simple model for the ratio of thermal- to population-grating scattering intensities that varies as P 4 T -4.4 . Preliminary investigations of the temperature dependence and detailed studies of the pressure dependence are in agreement with this model. Measurements of the temporal evolution and the peak intensity of isolated thermal-grating signals are in detailed agreement with calculations based on a linearized hydrodynamic model [J. Opt. Soc. Am. B 12, 384 (1995)]. copyright 1995 Optical Society of America

  9. Thermal and oxidative degradation studies of formulated C-ethers by gel-permeation chromatography

    Science.gov (United States)

    Jones, W. R., Jr.; Morales, W.

    1982-01-01

    Gel-permeation chromatography was used to analyze C-ether lubricant formulations from high-temperature bearing tests and from micro-oxidation tests. Three mu-styragel columns (one 500 and two 100 A) and a tetrahydrofuran mobile phase were found to adequately separate the C-ether degradation products. The micro-oxidation tests yielded degradation results qualitatively similar to those observed from the bearing tests. Micro-oxidation tests conducted in air yielded more degradation than did tests in nitrogen. No great differences were observed between the thermal-oxidative stabilities of the two C-ether formulations or between the catalytic degradation activities of silver and M-50 steel. C-ether formulation I did yield more degradation than did formulation II in 111- and 25-hour bearing tests, respectively.

  10. Local electrical properties of thermally grown oxide films formed on duplex stainless steel surfaces

    Science.gov (United States)

    Guo, L. Q.; Yang, B. J.; He, J. Y.; Qiao, L. J.

    2018-06-01

    The local electrical properties of thermally grown oxide films formed on ferrite and austenite surfaces of duplex stainless steel at different temperatures were investigated by Current sensing atomic force microscopy, X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES). The current maps and XPS/AES analyses show that the oxide films covering austenite and ferrite surfaces formed at different temperatures exhibit different local electrical characteristics, thickness and composition. The dependence of electrical conductivity of oxide films covering austenite and ferrite surface on the formation temperature is attributed to the film thickness and semiconducting structures, which is intrinsically related to thermodynamics and kinetics process of film grown at different temperature. This is well elucidated by corresponding semiconductor band structures of oxide films formed on austenite and ferrite phases at different temperature.

  11. Thermally oxidized titania nanotubes enhance the corrosion resistance of Ti6Al4V.

    Science.gov (United States)

    Grotberg, John; Hamlekhan, Azhang; Butt, Arman; Patel, Sweetu; Royhman, Dmitry; Shokuhfar, Tolou; Sukotjo, Cortino; Takoudis, Christos; Mathew, Mathew T

    2016-02-01

    The negative impact of in vivo corrosion of metallic biomedical implants remains a complex problem in the medical field. We aimed to determine the effects of electrochemical anodization (60V, 2h) and thermal oxidation (600°C) on the corrosive behavior of Ti-6Al-4V, with serum proteins, at physiological temperature. Anodization produced a mixture of anatase and amorphous TiO2 nanopores and nanotubes, while the annealing process yielded an anatase/rutile mixture of TiO2 nanopores and nanotubes. The surface area was analyzed by the Brunauer-Emmett-Teller method and was estimated to be 3 orders of magnitude higher than that of polished control samples. Corrosion resistance was evaluated on the parameters of open circuit potential, corrosion potential, corrosion current density, passivation current density, polarization resistance and equivalent circuit modeling. Samples both anodized and thermally oxidized exhibited shifts of open circuit potential and corrosion potential in the noble direction, indicating a more stable nanoporous/nanotube layer, as well as lower corrosion current densities and passivation current densities than the smooth control. They also showed increased polarization resistance and diffusion limited charge transfer within the bulk oxide layer. The treatment groups studied can be ordered from greatest corrosion resistance to least as Anodized+Thermally Oxidized > Anodized > Smooth > Thermally Oxidized for the conditions investigated. This study concludes that anodized surface has a potential to prevent long term implant failure due to corrosion in a complex in-vivo environment. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Accelerated thermal and radiation-oxidation combined degradation of electric cable insulation materials

    International Nuclear Information System (INIS)

    Yagi, Toshiaki; Seguchi, Tadao; Yoshida, Kenzo

    1986-03-01

    For the development of accelerated testing methodology to estimate the life time of electric cable, which is installed in radiation field such as a nuclear reactor containment vessel, radiation and thermal combined degradation of cable insulation and jacketing materials was studied. The materials were two types of formulated polyethylene, ethylene-propylene rubber, Hypalon, and Neoprene. With Co-60 γ-rays the materials were irradiated up to 0.5 MGy under vacuum and in oxygen under pressure, then exposed to thermal aging at elevated temperature in oxygen. The degradation was investigated by the tensile test, gelfraction, and swelling measurements. The thermal degradation rate for each sample increases with increase of oxygen concentration, i.e. oxygen pressure, during the aging, and tends to saturate above 0.2 MPa of oxygen pressure. Then, the effects of irradiation and the temperature on the thermal degradation rate were investigated at the oxygen pressure of 0.2 MPa in the temperature range from 110 deg C to 150 deg C. For all of samples irradiated in oxygen, the following thermal degradation rate was accelerated by several times comparing with unirradiated samples, while the rate of thermal degradation for the sample except Neoprene irradiated under vacuum was nearly equal to that of unirradiated one. By the analysis of thermal degradation rate against temperature using Arrhenius equation, it was found that the activation energy tends to decrease for the samples irradiated in oxidation condition. (author)

  13. Thermally stimulated iron oxide transformations and magnetic behaviour of cerium dioxide/iron oxide reactive sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Luňáček, J., E-mail: jiri.lunacek@vsb.cz [Department of Physics, VŠB – Technical University of Ostrava, 17, listopadu 15/2172, 708 33 Ostrava-Poruba (Czech Republic); Department 606, VŠB – Technical University of Ostrava, 17, listopadu 15/2172, 708 33 Ostrava-Poruba (Czech Republic); Životský, O. [Department of Physics, VŠB – Technical University of Ostrava, 17, listopadu 15/2172, 708 33 Ostrava-Poruba (Czech Republic); Department 606, VŠB – Technical University of Ostrava, 17, listopadu 15/2172, 708 33 Ostrava-Poruba (Czech Republic); Jirásková, Y. [CEITEC IPM, Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Žižkova 22, 616 62 Brno (Czech Republic); Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Žižkova 22, 616 62 Brno (Czech Republic); Buršík, J. [Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Žižkova 22, 616 62 Brno (Czech Republic); Janoš, P. [Faculty of the Environment, University of Jan Evangelista Purkyně, Králova Výšina 7, 400 96 Ústí nad Labem (Czech Republic)

    2016-10-15

    The present paper is devoted to detailed study of the magnetically separable sorbents based on a cerium dioxide/iron oxide composite annealed at temperatures T{sub a} = 773 K, 873 K, and 973 K. The X-ray diffraction and high resolution transmission electron microscopy are used to determine the phase composition and microstructure morphology. Mössbauer spectroscopy at room (300 K) and low (5 K) temperatures has contributed to more exact identification of iron oxides and their transformations Fe{sub 3}O{sub 4} → γ-Fe{sub 2}O{sub 3} (ε-Fe{sub 2}O{sub 3}) → α-Fe{sub 2}O{sub 3} in dependence on calcination temperature. Different iron oxide phase compositions and grain size distributions influence the magnetic characteristics determined from the room- and low-temperature hysteresis loop measurements. The results are supported by zero-field-cooled and field-cooled magnetization measurements allowing a quantitative estimation of the grain size distribution and its effect on the iron oxide transformations. - Highlights: •Magnetically separable sorbents based on a CeO{sub 2}/Fe{sub 2}O{sub 3} composite were investigated. •Microstructure of sorbents was determined by XRD, TEM and Mössbauer spectroscopy. •Magnetic properties were studied by hysteresis loops at room- and low-temperatures. •Phase transitions of iron oxides with increasing annealing temperature are observed.

  14. White balance tester with color sensor for industrial applications

    Science.gov (United States)

    Chen, Jiasheng; Zhu, XiaoSong

    1996-12-01

    The white balance tester is an instrument that adjusts the white balance for color TVs, monitors, and PC displays. We have designed a new white balance tester for use directly at the production line. It picks up the R (Red), G (Green), and B (Blue) signals for the screen using color sensors, compares the signals with the data previously stored in the internal memory, displays their differences with LED bars in the compare mode or displays x y Y, u v Y, JND (just noticeable difference) as well as correlated color temperature in the numerical mode. A built-in TV signal generator sets the luminance of the adjusting screen to the brightness of the reference white screen automatically. A 16-bit single chip microcomputer processes the measured values and controls the output levels of the TV signal generator.

  15. Improving deposition tester to study adherent deposits in papermaking

    OpenAIRE

    Monte Lara, Concepción; Sánchez, Mónica; Blanco Suárez, Ángeles; Negro Álvarez, Carlos; Tijero Miquel, Julio

    2012-01-01

    Conventional methods used for the quantification of adherent material contained in a pulp suspension propose either filtration of the sample, which may lead to loss of sticky material in the filtrate, or dilution of the pulp, which may cause destabilization of the dissolved and colloidal material; thus, leading to unreliable results. In 1998, the Cellulose and Paper Group of University Complutense of Madrid developed a deposition tester which aimed to quantify the adherence of material (micro...

  16. Tester Detects Steady-Short Or Intermittent-Open Circuits

    Science.gov (United States)

    Anderson, Bobby L.

    1990-01-01

    Momentary open circuits or steady short circuits trigger buzzer. Simple, portable, lightweight testing circuit sounds long-duration alarm when it detects steady short circuit or momentary open circuit in coaxial cable or other two-conductor transmission line. Tester sensitive to discontinuities lasting 10 microseconds or longer. Used extensively for detecting intermittent open shorts in accelerometer and extensometer cables. Also used as ordinary buzzer-type continuity checker to detect steady short or open circuits.

  17. Thermal oxidation of nuclear graphite: A large scale waste treatment option

    Science.gov (United States)

    Jones, Abbie N.; Marsden, Barry J.

    2017-01-01

    This study has investigated the laboratory scale thermal oxidation of nuclear graphite, as a proof-of-concept for the treatment and decommissioning of reactor cores on a larger industrial scale. If showed to be effective, this technology could have promising international significance with a considerable impact on the nuclear waste management problem currently facing many countries worldwide. The use of thermal treatment of such graphite waste is seen as advantageous since it will decouple the need for an operational Geological Disposal Facility (GDF). Particulate samples of Magnox Reactor Pile Grade-A (PGA) graphite, were oxidised in both air and 60% O2, over the temperature range 400–1200°C. Oxidation rates were found to increase with temperature, with a particular rise between 700–800°C, suggesting a change in oxidation mechanism. A second increase in oxidation rate was observed between 1000–1200°C and was found to correspond to a large increase in the CO/CO2 ratio, as confirmed through gas analysis. Increasing the oxidant flow rate gave a linear increase in oxidation rate, up to a certain point, and maximum rates of 23.3 and 69.6 mg / min for air and 60% O2 respectively were achieved at a flow of 250 ml / min and temperature of 1000°C. These promising results show that large-scale thermal treatment could be a potential option for the decommissioning of graphite cores, although the design of the plant would need careful consideration in order to achieve optimum efficiency and throughput. PMID:28793326

  18. Thermal oxidation of nuclear graphite: A large scale waste treatment option.

    Directory of Open Access Journals (Sweden)

    Alex Theodosiou

    Full Text Available This study has investigated the laboratory scale thermal oxidation of nuclear graphite, as a proof-of-concept for the treatment and decommissioning of reactor cores on a larger industrial scale. If showed to be effective, this technology could have promising international significance with a considerable impact on the nuclear waste management problem currently facing many countries worldwide. The use of thermal treatment of such graphite waste is seen as advantageous since it will decouple the need for an operational Geological Disposal Facility (GDF. Particulate samples of Magnox Reactor Pile Grade-A (PGA graphite, were oxidised in both air and 60% O2, over the temperature range 400-1200°C. Oxidation rates were found to increase with temperature, with a particular rise between 700-800°C, suggesting a change in oxidation mechanism. A second increase in oxidation rate was observed between 1000-1200°C and was found to correspond to a large increase in the CO/CO2 ratio, as confirmed through gas analysis. Increasing the oxidant flow rate gave a linear increase in oxidation rate, up to a certain point, and maximum rates of 23.3 and 69.6 mg / min for air and 60% O2 respectively were achieved at a flow of 250 ml / min and temperature of 1000°C. These promising results show that large-scale thermal treatment could be a potential option for the decommissioning of graphite cores, although the design of the plant would need careful consideration in order to achieve optimum efficiency and throughput.

  19. The Development of HfO2-Rare Earth Based Oxide Materials and Barrier Coatings for Thermal Protection Systems

    Science.gov (United States)

    Zhu, Dongming; Harder, Bryan James

    2014-01-01

    Advanced hafnia-rare earth oxides, rare earth aluminates and silicates have been developed for thermal environmental barrier systems for aerospace propulsion engine and thermal protection applications. The high temperature stability, low thermal conductivity, excellent oxidation resistance and mechanical properties of these oxide material systems make them attractive and potentially viable for thermal protection systems. This paper will focus on the development of the high performance and high temperature capable ZrO2HfO2-rare earth based alloy and compound oxide materials, processed as protective coating systems using state-or-the-art processing techniques. The emphasis has been in particular placed on assessing their temperature capability, stability and suitability for advanced space vehicle entry thermal protection systems. Fundamental thermophysical and thermomechanical properties of the material systems have been investigated at high temperatures. Laser high-heat-flux testing has also been developed to validate the material systems, and demonstrating durability under space entry high heat flux conditions.

  20. Spalling stress in oxidized thermal barrier coatings evaluated by X-ray diffraction method

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, K. [Faculty of Education and Human Sciences, Niigata Univ., Niigata (Japan); Tanaka, K. [Dept. of Mechanical Engineering, Nagoya Univ., Furoh-cho, Chikusa-ku, Nagoya (Japan)

    2005-07-01

    The spallation of thermal barrier coatings (TBCs) is promoted by thermally grown oxide (TGO). To improve TBCs, it is very important to understand the influence of TGO on the spalling stress. In this study 'the TBCs were oxidized at 1373 K for four different periods: 0, 500,1000 and 2000 h. The distribution of the in-plane stress in oxidized TBCs, {sigma}{sub 1}, was obtained by repeating the X-ray stress measurement with low energy X-rays after successive removal of the surface layer. The distribution of the out-of-plane stress, {sigma}{sub 1} - {sigma}{sub 3}, was measured with hard synchrotron X-rays, because high energy X-rays have a large penetration depth. From the results by the low and high energy X-rays, the spalling stress in the oxidized TBCs, {sigma}{sub 3}, was evaluated. The evaluated value of the spalling stress for the oxidized TBC was a small tension beneath the surface, but steeply increased near the interface between the top and bond coating. This large tensile stress near the interface is responsible for the spalling of the top coating. (orig.)

  1. Ionic Conductance, Thermal and Morphological Behavior of PEO-Graphene Oxide-Salts Composites

    Directory of Open Access Journals (Sweden)

    Mohammad Saleem Khan

    2015-01-01

    Full Text Available Thin films composites of poly(ethylene oxide-graphene oxide were fabricated with and without lithium salts by solvent cast method. The ionic conductivity of these composites was studied at various concentrations of salt polymer-GO complexes and at different temperatures. The effects of temperature and graphene oxide concentration were measured from Arrhenius conductance plots. It is shown that the addition of salts in pure PEO increases conductance many times. The graphene oxide addition has enhanced the conductance approximately 1000 times as compared to that of pure PEO. The activation energies were determined for all the systems which gave higher values for pure PEO and the value decreased with the addition of LiClO4 and LiCl salts and further decreases with the addition of graphene oxide. The composite has also lowered the activation energy values which mean that incorporation of GO in PEO has decreased crystallinity and the amorphous region has increased the local mobility of polymer chains resulting in lower activation energies. SEM analysis shows uniform distribution of GO in polymer matrix. The thermal stability studies reveal that incorporation of GO has somewhat enhanced the thermal stability of the films.

  2. Volatilisation of ruthenium in vitrification. Isothermal calcination studies of 'Magnox' and thermal oxide simulates

    International Nuclear Information System (INIS)

    Cains, P.W.; Hay, D.A.

    1982-12-01

    Ru volatilities have been measured for the static, isothermal calcination of ''Magnox'' and Thermal Oxide HAL's (Highly Active Liquors) at temperatures up to 600 0 C. Model solutions containing Ru, HNO 3 , and nitrates of important individual cations have also been investigated. Experimental design was primarily based on the requirements of rotary calcination process development. The results have been interpreted in terms of a reaction model involving competition between the simple degradation of Ru(NO) complexes to RuO 2 and oxidative decomposition to volatile species (e.g. RuO 4 ). (author)

  3. Novel Materials through Non-Hydrolytic Sol-Gel Processing: Negative Thermal Expansion Oxides and Beyond

    Directory of Open Access Journals (Sweden)

    Cora Lind

    2010-04-01

    Full Text Available Low temperature methods have been applied to the synthesis of many advanced materials. Non-hydrolytic sol-gel (NHSG processes offer an elegant route to stable and metastable phases at low temperatures. Excellent atomic level homogeneity gives access to polymorphs that are difficult or impossible to obtain by other methods. The NHSG approach is most commonly applied to the preparation of metal oxides, but can be easily extended to metal sulfides. Exploration of experimental variables allows control over product stoichiometry and crystal structure. This paper reviews the application of NHSG chemistry to the synthesis of negative thermal expansion oxides and selected metal sulfides.

  4. The Coadministration of Unoxidized and Oxidized Desi Ghee Ameliorates the Toxic Effects of Thermally Oxidized Ghee in Rabbits

    Directory of Open Access Journals (Sweden)

    Alam Zeb

    2017-01-01

    Full Text Available Desi Ghee was thermally oxidized at 160°C for 9 h and characterized for peroxide value (PV, free fatty acid (FFA, thiobarbituric acid reactive substances (TBARS, radical scavenging activity (RSA, and fatty acid and cholesterol composition using GC-MS. Oxidized (OG and normal ghee (NG were fed to rabbits in different doses. Blood was collected for hematology and biochemical analyses after 7 and 14 days. The oxidation of desi ghee increased the PV, FFA, and TBARS values and showed a decline in the RSA values. GC-MS revealed that desi ghee was rich in saturated fatty acids (55.9 g/100 g and significant amounts of oleic acid (26.2 g/100 g. The OG significantly decreased the body weight, which was normalized by the coadministration of NG. Serum lipid profile showed a dose dependent increase in total cholesterol, triglycerides, and low density lipoproteins (LDL and decrease in RBCs count, hematocrit, glucose, and hemoglobin concentration with OG feeding. These parameters were normalized by coadministration of NG. Liver histopathology of OG fed groups showed bile duct dilation and necrotic changes, while normal architecture showed in NG groups, compared to control. These results indicate that NG has no significant effect on rabbits comparing with OG and that it was beneficial when coadministered with oxidized ghee.

  5. Photoelectrochemical and electrocatalytic properties of thermally oxidized copper oxide for efficient solar fuel production

    KAUST Repository

    Garcia Esparza, Angel T.; Limkrailassiri, Kevin; Leroy, Fré dé ric; Rasul, Shahid; Yu, Weili; Lin, Liwei; Takanabe, Kazuhiro

    2014-01-01

    We report the use of a facile and highly scalable synthesis process to control growth products of earth-abundant Cu-based oxides and their application in relevant photoelectrochemical and electrochemical solar fuel generation systems. Characterization of the synthesized Cu(I)/Cu(II) oxides indicates that their surface morphology and chemical composition can be simply tuned by varying two synthesis parameters (time and temperature). UV-Vis spectroscopy and impedance spectroscopy studies are performed to estimate the band structures and electronic properties of these p-type semiconductor materials. Photoelectrodes made of Cu oxides possess favorable energy band structures for production of hydrogen from water; the position of their conduction band is ≈1 V more negative than the water-reduction potential. High acceptor concentrations on the order of 1018-1019 cm-3 are obtained, producing large electric fields at the semiconductor-electrolyte interface and thereby enhancing charge separation. The highly crystalline pristine samples used as photocathodes in photoelectrochemical cells exhibit high photocurrents under AM 1.5G simulated illumination. When the samples are electrochemically reduced under galvanostatic conditions, the co-existence of the oxide with metallic Cu on the surface seems to function as an effective catalyst for the selective electrochemical reduction of CO2. © the Partner Organisations 2014.

  6. Planar Indium Tin Oxide Heater for Improved Thermal Distribution for Metal Oxide Micromachined Gas Sensors

    Directory of Open Access Journals (Sweden)

    M. Cihan Çakır

    2016-09-01

    Full Text Available Metal oxide gas sensors with integrated micro-hotplate structures are widely used in the industry and they are still being investigated and developed. Metal oxide gas sensors have the advantage of being sensitive to a wide range of organic and inorganic volatile compounds, although they lack selectivity. To introduce selectivity, the operating temperature of a single sensor is swept, and the measurements are fed to a discriminating algorithm. The efficiency of those data processing methods strongly depends on temperature uniformity across the active area of the sensor. To achieve this, hot plate structures with complex resistor geometries have been designed and additional heat-spreading structures have been introduced. In this work we designed and fabricated a metal oxide gas sensor integrated with a simple square planar indium tin oxide (ITO heating element, by using conventional micromachining and thin-film deposition techniques. Power consumption–dependent surface temperature measurements were performed. A 420 °C working temperature was achieved at 120 mW power consumption. Temperature distribution uniformity was measured and a 17 °C difference between the hottest and the coldest points of the sensor at an operating temperature of 290 °C was achieved. Transient heat-up and cool-down cycle durations are measured as 40 ms and 20 ms, respectively.

  7. Planar Indium Tin Oxide Heater for Improved Thermal Distribution for Metal Oxide Micromachined Gas Sensors.

    Science.gov (United States)

    Çakır, M Cihan; Çalışkan, Deniz; Bütün, Bayram; Özbay, Ekmel

    2016-09-29

    Metal oxide gas sensors with integrated micro-hotplate structures are widely used in the industry and they are still being investigated and developed. Metal oxide gas sensors have the advantage of being sensitive to a wide range of organic and inorganic volatile compounds, although they lack selectivity. To introduce selectivity, the operating temperature of a single sensor is swept, and the measurements are fed to a discriminating algorithm. The efficiency of those data processing methods strongly depends on temperature uniformity across the active area of the sensor. To achieve this, hot plate structures with complex resistor geometries have been designed and additional heat-spreading structures have been introduced. In this work we designed and fabricated a metal oxide gas sensor integrated with a simple square planar indium tin oxide (ITO) heating element, by using conventional micromachining and thin-film deposition techniques. Power consumption-dependent surface temperature measurements were performed. A 420 °C working temperature was achieved at 120 mW power consumption. Temperature distribution uniformity was measured and a 17 °C difference between the hottest and the coldest points of the sensor at an operating temperature of 290 °C was achieved. Transient heat-up and cool-down cycle durations are measured as 40 ms and 20 ms, respectively.

  8. Effect of thermally grown oxide (TGO) microstructure on the durability of TBCs with PtNiAl diffusion bond coats

    Energy Technology Data Exchange (ETDEWEB)

    Spitsberg, Irene [Materials and Process Engineering Department, GE Aircraft Engines, Evendale, OH (United States)]. E-mail: irene.spitsberg@kennametal.com; More, Karren [Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN (United States)

    2006-02-15

    The role of pre-oxidation surface treatments on the oxide microstructure and the failure mechanism of multi-layer thermal barrier systems based on Pt-modified NiAl bond coats and electron beam deposited thermal barrier coatings (TBCs) have been studied. The primary pre-oxidation experimental variable was the partial pressure of oxygen in the pre-oxidizing atmosphere at constant temperature and bond coat composition. The durability of TBCs deposited on surfaces following different pre-oxidation treatments were measured and compared using furnace cycling tests. The oxide layers corresponding to different levels of TBC performance were characterized microstructurally, chemically, and compositionally using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) techniques. TBC performance was enhanced by the formation of a surface oxide having a coarse-grained columnar structure during the pre-oxidation process. Increased TBC durability was consistent with a slower oxide growth rate during exposure of the TBC to high-temperature, cyclic conditions, as was observed for this particular pre-oxidation condition. An oxide microstructure having fewer through-thickness transport pathways (grain boundaries) should also result in slower lateral oxide growth rates, consistent with a slowed rate of ratcheting as was observed in the pre-oxidized samples that had the best TBC performance. The desired surface oxide grain structure was achieved by pre-oxidizing the bond coat prior to TBC deposition at an intermediate partial pressure of oxygen.

  9. Nanocrystalline transition metal oxides as catalysts in the thermal decomposition of ammonium perchlorate

    Energy Technology Data Exchange (ETDEWEB)

    Kapoor, Inder Pal Singh; Srivastava, Pratibha; Singh, Gurdip [Department of Chemistry, DDU Gorakhpur University, Gorakhpur (India)

    2009-08-15

    Nanocrystalline transition metal oxides (NTMOs) have been successfully prepared by three different methods: novel quick precipitation method (Cr{sub 2}O{sub 3} and Fe{sub 2}O{sub 3}); surfactant mediated method (CuO), and reduction of metal complexes with hydrazine as reducing agent (Mn{sub 2}O{sub 3}). The nano particles have been characterized by X-ray diffraction (XRD) which shows an average particle diameter of 35-54 nm. Their catalytic activity was measured in the thermal decomposition of ammonium perchlorate (AP). AP decomposition undergoes a two step process where the addition of metal oxide nanocrystals led to a shifting of the high temperature decomposition peak toward lower temperature. The kinetics of the thermal decomposition of AP and catalyzed AP has also been evaluated using model fitting and isoconversional method. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  10. Preparation and properties of highly conductive palmitic acid/graphene oxide composites as thermal energy storage materials

    International Nuclear Information System (INIS)

    Mehrali, Mohammad; Latibari, Sara Tahan; Mehrali, Mehdi; Indra Mahlia, Teuku Meurah; Cornelis Metselaar, Hendrik Simon

    2013-01-01

    PA/GO (palmitic acid/graphene oxide) as PCMs (phase change materials) prepared by vacuum impregnation method, have high thermal conductivity. The GO (graphene oxide) composite was used as supporting material to improve thermal conductivity and shape stabilization of composite PCM (phase change material). SEM (Scanning electronic microscope), FT-IR (Fourier transformation infrared spectroscope) and XRD (X-ray diffractometer) were applied to determine microstructure, chemical structure and crystalloid phase of palmitic acid/GO composites, respectively. DSC (Differential scanning calorimeter) test was done to investigate thermal properties which include melting and solidifying temperatures and latent heat. FT-IR analysis represented that the composite instruction of porous palmitic acid and GO were physical. The temperatures of melting, freezing and latent heats of the composite measured through DSC analysis were 60.45, 60.05 °C, 101.23 and 101.49 kJ/kg, respectively. Thermal cycling test showed that the form-stable composite PCM has good thermal reliability and chemical stability. Thermal conductivity of the composite PCM was improved by more than three times from 0.21 to 1.02. As a result, due to their acceptable thermal properties, good thermal reliability, chemical stability and great thermal conductivities, we can consider the prepared form-stable composites as highly conductive PCMs for thermal energy storage applications. - Highlights: • Novel composite PCM with high thermal conductivity and latent heat storage. • New thermal cycling test for thermal reliability of composite PCMs. • Increasing thermal conductivity of composite PCM with graphene oxide. • Increasing thermal stability of phase change material by adding graphene oxide

  11. Unique Crystal Orientation of Poly(ethylene oxide) Thin Films by Crystallization Using a Thermal Gradient

    DEFF Research Database (Denmark)

    Gbabode, Gabin; Delvaux, Maxime; Schweicher, Guillaume

    2017-01-01

    Poly(ethylene oxide), (PEO), thin films of different thicknesses (220, 450, and 1500 nm) and molecular masses (4000, 8000, and 20000 g/mol) have been fabricated by spin-coating of methanol solutions onto glass substrates. All these samples have been recrystallized from the melt using a directional......, to significantly decrease the distribution of crystal orientation obtained after crystallization using the thermal gradient technique....

  12. Heat recovery investigation from dryer–thermal oxidizer system in corn-ethanol plants

    International Nuclear Information System (INIS)

    Olszewski, Pawel

    2015-01-01

    In recent years, annual corn ethanol production in the U.S. has exceeded 13,298,000,000 gallons. However, net energy balance for this sector became a subject of controversy in many discussions. The aim of the presented research is an investigation of thermal improvement opportunities in a corn ethanol plant. For this purpose, a complex mathematical model was developed for a dryer–thermal oxidizer system. Three variants were subjected thermodynamic analyses: one state of the art system and two proposed system modifications. The properties of humid gas, a mixture of combustion products and moisture evaporated from distiller's grain, were updated based on the steam properties according to the formulation proposed by the International Association for the Properties of Water and Steam. All calculations were performed by uniquely-developed C++ code. The results indicate major potential for improvement in the following areas: (i) water recovery from humid gas; (ii) heat recovery from moisture condensation – max. 44% of total primary energy usage (TPEU); and (iii) fuel savings by reduction of humid gas flow through a thermal oxidizer – max. 1.4% of TPEU. Also the presented analysis can be a starting point for further modifications in real corn ethanol manufacturing applications, leading towards pilot system implementation. - Highlights: • Mathematical model for dryer–oxidizer system in a corn ethanol plant was proposed. • Three configurations were discussed: with intercooler, regenerator, and recuperator. • Recovery rate of water condensed at various conditions and locations was quantified. • Heat recovery possibilities at various temperatures and locations have been assessed. • Energy savings in thermal oxidizer due to preliminary condensation were calculated

  13. Effect of Thermally Reduced Graphene Oxide on Mechanical Properties of Woven Carbon Fiber/Epoxy Composite

    OpenAIRE

    Nitai Chandra Adak; Suman Chhetri; Naresh Chandra Murmu; Pranab Samanta; Tapas Kuila

    2018-01-01

    Thermally reduced graphene oxide (TRGO) was incorporated as a reinforcing filler in the epoxy resin to investigate the effect on the mechanical properties of carbon fiber (CF)/epoxy composites. At first, the epoxy matrix was modified by adding different wt % of TRGO from 0.05 to 0.4 wt % followed by the preparation of TRGO/CF/epoxy composites througha vacuum-assisted resin transfer molding process. The prepared TRGO was characterized by using Fourier transform infrared spectroscopy, Raman Spe...

  14. Using Coupled Mesoscale Experiments and Simulations to Investigate High Burn-Up Oxide Fuel Thermal Conductivity

    Science.gov (United States)

    Teague, Melissa C.; Fromm, Bradley S.; Tonks, Michael R.; Field, David P.

    2014-12-01

    Nuclear energy is a mature technology with a small carbon footprint. However, work is needed to make current reactor technology more accident tolerant and to allow reactor fuel to be burned in a reactor for longer periods of time. Optimizing the reactor fuel performance is essentially a materials science problem. The current understanding of fuel microstructure have been limited by the difficulty in studying the structure and chemistry of irradiated fuel samples at the mesoscale. Here, we take advantage of recent advances in experimental capabilities to characterize the microstructure in 3D of irradiated mixed oxide (MOX) fuel taken from two radial positions in the fuel pellet. We also reconstruct these microstructures using Idaho National Laboratory's MARMOT code and calculate the impact of microstructure heterogeneities on the effective thermal conductivity using mesoscale heat conduction simulations. The thermal conductivities of both samples are higher than the bulk MOX thermal conductivity because of the formation of metallic precipitates and because we do not currently consider phonon scattering due to defects smaller than the experimental resolution. We also used the results to investigate the accuracy of simple thermal conductivity approximations and equations to convert 2D thermal conductivities to 3D. It was found that these approximations struggle to predict the complex thermal transport interactions between metal precipitates and voids.

  15. Thermal transport properties of polycrystalline tin-doped indium oxide films

    International Nuclear Information System (INIS)

    Ashida, Toru; Miyamura, Amica; Oka, Nobuto; Sato, Yasushi; Shigesato, Yuzo; Yagi, Takashi; Taketoshi, Naoyuki; Baba, Tetsuya

    2009-01-01

    Thermal diffusivity of polycrystalline tin-doped indium oxide (ITO) films with a thickness of 200 nm has been characterized quantitatively by subnanosecond laser pulse irradiation and thermoreflectance measurement. ITO films sandwiched by molybdenum (Mo) films were prepared on a fused silica substrate by dc magnetron sputtering using an oxide ceramic ITO target (90 wt %In 2 O 3 and 10 wt %SnO 2 ). The resistivity and carrier density of the ITO films ranged from 2.9x10 -4 to 3.2x10 -3 Ω cm and from 1.9x10 20 to 1.2x10 21 cm -3 , respectively. The thermal diffusivity of the ITO films was (1.5-2.2)x10 -6 m 2 /s, depending on the electrical conductivity. The thermal conductivity carried by free electrons was estimated using the Wiedemann-Franz law. The phonon contribution to the heat transfer in ITO films with various resistivities was found to be almost constant (λ ph =3.95 W/m K), which was about twice that for amorphous indium zinc oxide films

  16. The fabrication and thermal properties of bismuth-aluminum oxide nanothermometers.

    Science.gov (United States)

    Wang, Chiu-Yen; Chen, Shih-Hsun; Tsai, Ping-Hsin; Chiou, Chung-Han; Hsieh, Sheng-Jen

    2017-01-27

    Bismuth (Bi) nanowires, well controlled in length and diameter, were prepared by using an anodic aluminum oxide (AAO) template-assisted molding injection process with a high cooling rate. A high performance atomic layer deposition (ALD)-capped bismuth-aluminum oxide (Bi-Al 2 O 3 ) nanothermometer is demonstrated that was fabricated via a facile, low-cost and low-temperature method, including AAO templated-assisted molding injection and low-temperature ALD-capped processes. The thermal behaviors of Bi nanowires and Bi-Al 2 O 3 nanocables were studied by in situ heating transmission electron microscopy. Linear thermal expansion of liquid Bi within native bismuth oxide nanotubes and ALD-capped Bi-Al 2 O 3 nanocables were evaluated from 275 °C to 700 °C and 300 °C to 1000 °C, respectively. The results showed that the ALD-capped Bi-Al 2 O 3 nanocable possesses the highest working temperature, 1000 °C, and the broadest operation window, 300 °C-1000 °C, of a thermal-expanding type nanothermometer. Our innovative approach provides another way of fabricating core-shell nanocables and to further achieve sensing local temperature under an extreme high vacuum environment.

  17. Numerical investigation of influence thermal preparation coal on nitric oxides formation in combustion process

    Energy Technology Data Exchange (ETDEWEB)

    Chernetskaya, N. [Siberian Federal Univ., Krasnoyarsk (Russian Federation); Chernetsky, M.; Dekterev, A. [Siberian Federal Univ., Krasnoyarsk (Russian Federation); Kutateladze Institute of Thermophysics, Novosibirsk (Russian Federation)

    2013-07-01

    Emissions of nitrogen oxides from coal combustion are a major environmental problem because they have been shown to contribute to the formation of acid rain and photochemical smog. Coal thermalpreparation before furnace delivery is effective method to reduce NOx emissions, shown by experiments in small-scale facilities (Babiy VI, Alaverdov PI, Influence of thermal preparation pulverized coal on nitric oxides outlet for combustion different metamorphized coal. ATI, 1983). This paper presents the mathematical model of burning thermal preparation coal. Validation of the model was carried out on laboratory-scale plant of All-Russia thermal engineering institute. Modeling of low-emissive burner with preliminary heating coal dust is made for the purpose of search of burner optimal constructions which provides low concentration of nitric oxides in the boiler. For modeling are used in-house CFD code ''{sigma}Flow'' (Dekterev AA, Gavrilov AA, Harlamov EB, Litvintcev KY, J Comput Technol 8(Part 1):250-255, 2003).

  18. Sludge thermal oxidation processes: mineral recycling, energy impact, and greenhouse effect gases release

    Energy Technology Data Exchange (ETDEWEB)

    Guibelin, Eric

    2003-07-01

    Different treatment routes have been studied for a mixed sludge: the conventional agricultural use is compared with the thermal oxidation processes, including incineration (in gaseous phase) and wet air oxidation (in liquid phase). The interest of a sludge digestion prior to the final treatment has been also considered according to the two major criteria, which are the fossil energy utilisation and the greenhouse effect gases (CO{sub 2}, CH{sub 4}, N{sub 2}O) release. Thermal energy has to be recovered on thermal processes to make these processes environmentally friendly, otherwise their main interest is to extract or destroy micropollutants and pathogens from the carbon cycle. In case of continuous energy recovery, incineration can produce more energy than it consumes. Digestion is especially interesting for agriculture: according to these two schemes, the energy final balance can also be in excess. As to wet air oxidation, it is probably one of the best way to minimize greenhouse effect gases emission. (author)

  19. Wet oxidative degradation of cellulosic wastes 5- chemical and thermal properties of the final waste forms

    International Nuclear Information System (INIS)

    Eskander, S.B.; Saleh, H.M.

    2002-01-01

    In this study, the residual solution arising from the wet oxidative degradation of solid organic cellulosic materials, as one of the component of radioactive solid wastes, using hydrogen peroxide as oxidant. Were incorporated into ordinary Portland cement matrix. Leaching as well as thermal characterizations of the final solidified waste forms were evaluated to meet the final disposal requirements. Factors, such as the amount of the residual solution incorporated, types of leachant. Release of different radionuclides and freezing-thaw treatment, that may affect the leaching characterization. Were studied systematically from the data obtained, it was found that the final solid waste from containing 35% residual solution in tap water is higher than that in ground water or sea water. Based on the data obtained from thermal analysis, it could be concluded that incorporating the residual solution form the wet oxidative degradation of cellulosic materials has no negative effect on the hydration of cement materials and consequently on the thermal stability of the final solid waste from during the disposal process

  20. Thin copper oxide films prepared by ion beam sputtering with subsequent thermal oxidation: Application in chemiresistors

    Czech Academy of Sciences Publication Activity Database

    Horák, Pavel; Bejšovec, Václav; Vacík, Jiří; Lavrentiev, Vasyl; Vrňata, M.; Kormunda, M.; Daniš, S.

    2016-01-01

    Roč. 389, DEC (2016), s. 751-759 ISSN 0169-4332 R&D Projects: GA ČR(CZ) GBP108/12/G108; GA MŠk(CZ) LM2011019 Institutional support: RVO:61389005 Keywords : Copper oxide * ion beam sputtering * Van der Pauw * nuclear reaction analysis * gas sensing Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.387, year: 2016

  1. Development of uranium dioxide fuel pellets with addition of beryllium oxide for increasing of thermal conductivity

    International Nuclear Information System (INIS)

    Queiroz, Carolinne Mol; Ferreira, Ricardo Alberto Neto

    2011-01-01

    The CDTN - Centro de Desenvolvimento de Tecnologia Nuclear presents a project named 'Beryllium Project' viewing to increasing the thermal conductivity of UO 2 fuel pellets, increasing the lifetime of those pellets in the reactor, generating a greater economy. This increase of conductivity is obtained by means of Be O addition to the UO 2 fuel pellets, which is very used for the production of nuclear energy. The UO 2 pellets however present a thermal conductivity relatively low, generating a high temperature gradient between the center and his side surface. The addition of beryllium oxide, with higher thermal conductivity gives pellets which will present lower temperature gradient and, consequently, more durability and better utilization of energy potential of the pellet in the reactor. (author)

  2. Physicochemical Characteristics and Lipid Oxidation of Chicken Inner Fillets Subjected to Different Thermal Processing Types

    Directory of Open Access Journals (Sweden)

    NN Arguelo

    Full Text Available ABSTRACT The objective of this study was to evaluate the effects of different types of thermal processing on the physiochemical characteristics and lipid oxidation of chicken inner fillets. The study was divided into three assays. In the first assay, 50 chicken inner fillets were divided into five treatments, totaling 10 samples per treatment. Treatments consisted in cooking in water bath, electric oven, microwave oven, deep frying, or grilling. The analyzed variables were: cooking weight loss (CWL and lipid oxidation determined by thiobarbituric acid reactive substances (TBARS. In the second assay, 50 chicken inner fillets were divided into five treatments, totaling 10 samples per treatment. Each treatment consisted of the same cooking methods applied in the first assay, and storage for 48 hours under refrigeration and reheating in a microwave oven. The variable analyzed in the second assay was lipid oxidation (TBARS. In the third assay, 30 samples of chicken inner fillets were subjected to one, four and eight freeze-thaw cycles, after which meat pH, myofibrillar fragmentation index (MFI, water retention capacity (WRC, and lipid oxidation (TBARS were determined. Chicken inner fillets submitted to deep frying and cooked in a microwave oven presented greater lipid oxidation than the other cooking methods, and deep frying resulted in the highest cooking weight loss. Reheating chicken inner fillets in a microwave oven caused the highest meat lipid oxidation. Increasing the number of freeze-thaw cycles increases the pH, MFI, WRC and TBARS values of chicken inner fillets.

  3. Thermal Treatment of Cerium Oxide and Its Properties: Adsorption Ability versus Degradation Efficiency

    Directory of Open Access Journals (Sweden)

    Pavel Janoš

    2014-01-01

    Full Text Available Cerium oxide belongs to the most important heterogeneous catalysts, but its applicability as so-called reactive sorbent for the degradation of toxic chemicals was only recently discovered. For these purposes, cerium oxide is prepared by precipitation of insoluble cerium salts (carbonates with a subsequent thermal decomposition. Properties of cerium oxide prepared from the carbonate precursor are strongly affected by the temperature during the calcination. Main physicochemical properties of cerium oxide (specific surface area, crystallinity, and surface chemistry were examined in dependence on the calcination temperature. As the adsorptive properties of CeO2 are undoubtedly of great importance in the abovementioned applications, the adsorption ability was studied using an azo dye Acid Orange 7 (AO7 as a model compound. The highest sorption efficiency towards AO7 exhibited sorbents prepared at temperatures below 700°C, which was attributed mainly to the presence of hydroxyl groups on the oxide surface. A strong correlation was found between an adsorption efficiency of cerium oxides and their degradation efficiency for organophosphate pesticide parathion methyl. The >Ce–OH groups on the sorbent surface are responsible for the dye binding by the surface-complexation mechanism, and probably also for the nucleophilic cleavage of the P–O–aryl bond in the pesticide molecule.

  4. Synthesis, characterization and thermal expansion studies on thorium-praseodymium mixed oxide solid solutions

    International Nuclear Information System (INIS)

    Panneerselvam, G.; Antony, M.P.; Srinivasan, T.G.; Vasudeva Rao, P.R.

    2010-01-01

    Full text: Thorium-praseodymium mixed oxide solid solutions containing 15, 25, 40 and 55 mole percent of praseodymia were synthesized by mixing the solutions of thorium nitrate in water and praseodymium oxide (Pr 6 O 11 ) in conc. HNO 3 . Subsequently, their hydroxides were co-precipitated by the addition of aqueous ammonia. Further the precipitate was dried at 50 deg C, calcined at 600 deg C for 4 hours and sintered at 1200 deg C for 6 h in air. X-ray diffraction measurements were performed for phase identification and lattice parameter derivation. Single-phase fluorite structure was observed for all the compositions. Bulk and theoretical densities of solid solutions were also determined by immersion and X-ray techniques. Thermal expansion coefficients and percentage linear thermal expansion of the solid solutions were determined using high temperature X-ray diffraction technique in the temperature range 300 to 1700 K for the first time. The room temperature lattice constants estimated for above compositions are 0.5578, 0.5565, 0.5545 and 0.5526 nm, respectively. The mean linear thermal expansion coefficients for the solid solutions are 15.48 x 10 -6 K -1 , 18.35 x 10 -6 K -1 , 22.65 x 10 -6 K -1 and 26.95 x 10 -6 K -1 , respectively. The percentage linear thermal expansions in this temperature range are 1.68, 1.89, 2.21 and 2.51 respectively. It is seen that the solid solutions are stable up to 1700 K. It is also seen that the effect and nature of the dopant are the important parameters influencing the thermal expansion of the ThO 2 . The lattice parameter of the solid solutions exhibited a decreasing trend with respect to praseodymia addition. The percentage linear thermal expansion of the solid solutions increases steadily with increasing temperature

  5. The effect of ethyl pyruvate on oxidative stress in intestine and bacterial translocation after thermal injury.

    Science.gov (United States)

    Karabeyoğlu, Melih; Unal, Bülent; Bozkurt, Betül; Dolapçi, Iştar; Bilgihan, Ayşe; Karabeyoğlu, Işil; Cengiz, Omer

    2008-01-01

    Thermal injury causes a breakdown in the intestinal mucosal barrier due to ischemia reperfusion injury, which can induce bacterial translocation (BT), sepsis, and multiple organ failure in burn patients. The aim of this study was to investigate the effect of ethyl pyruvate (EP) on intestinal oxidant damage and BT in burn injury. Thirty-two rats were randomly divided into four groups. The sham group was exposed to 21 degrees C water and injected intraperitoneal with saline (1 mL/100 g). The sham + EP group received EP (40 mg/kg) intraperitoneally 6 h after the sham procedure. The burn group was exposed to thermal injury and given intraperitoneal saline injection (1 mL/100 g). The burn + EP group received EP (40 mg/kg) intraperitoneally 6 h after thermal injury. Twenty-four hours later, tissue samples were obtained from mesenteric lymph nodes, spleen, and liver for microbiological analysis and ileum samples were harvested for biochemical analysis. Thermal injury caused severe BT in burn group. EP supplementation decreased BT in mesenteric lymph nodes and spleen in the burn + EP group compared with the burn group (P < 0.05). Also, burn caused BT in liver, but this finding was not statistically significant among all groups. Thermal injury caused a statistically significant increase in malondialdehyde and myeloperoxidase levels, and EP prevented this effects in the burn + EP group compared with the burn group (P < 0.05). Our data suggested that EP can inhibit the BT and myeloperoxidase and malondialdehyde production in intestine following thermal injury, suggesting anti-inflammatory and anti-oxidant properties of EP.

  6. Fabrication and thermal oxidation of ZnO nano fibers prepared via electro spinning technique

    International Nuclear Information System (INIS)

    Baek, Jeongha; Park, Juyun; Kim, Don; Kang, Yongcheol; Koh, Sungwi; Kang, Jisoo

    2012-01-01

    Materials on the scale of nano scale have widely been used as research topics because of their interesting characteristics and aspects they bring into the field. Out of the many metal oxides, zinc oxide (ZnO) was chosen to be fabricated as nano fibers using the electro spinning method for potential uses of solar cells and sensors. After ZnO nano fibers were obtained, calcination temperature effects on the ZnO nano fibers were studied and reported here. The results of scanning electron microscopy (SEM) revealed that the aggregation of the ZnO nano fibers progressed by calcination. X-ray diffraction (XRD) study showed the hcp ZnO structure was enhanced by calcination at 873 and 1173 K. Transmission electron microscopy (TEM) confirmed the crystallinity of the calcined ZnO nano fibers. X-ray photoelectron spectroscopy (XPS) verified the thermal oxidation of Zn species by calcination in the nano fibers. These techniques have helped US deduce the facts that the diameter of ZnO increases as the calcination temperature was raised; the process of calcination affects the crystallinity of ZnO nano fibers, and the thermal oxidation of Zn species was observed as the calcination temperature was raised

  7. Increase of thermal conductivity of uranium dioxide nuclear fuel pellets with beryllium oxide addition

    International Nuclear Information System (INIS)

    Camarano, D.M.; Mansur, F.A.; Santos, A.M.M. dos; Ferraz, W.B.

    2016-01-01

    The UO_2 fuel is one of the most used nuclear fuel in thermal reactors and has many advantages such as high melting point, chemical compatibility with cladding, etc. However, its thermal conductivity is relatively low, which leads to a premature degradation of the fuel pellets due to a high radial temperature gradient during reactor operation. An alternative to avoid this problem is to increase the thermal conductivity of the fuel pellets, by adding beryllium oxide (BeO). Pellets of UO_2 and UO_2-BeO were obtained from a homogenized mixture of powders of UO_2 and BeO, containing 2% and 3% by weight of BeO and sintering at 1750 °C for 3 h under H_2 atmosphere after uniaxial pressing at 400 MPa. The pellet densities were obtained by xylol penetration-immersion method and the thermal diffusivity, specific heat and thermal conductivity were determined according to ASTM E-1461 at room temperature (25 deg C) and 100 deg C. The thermal diffusivity measurements were carried out employing the laser flash method. The thermal conductivity obtained at 25 deg C showed an increase with the addition of 2% and 3% of BeO corresponding to 19% and 28%, respectively. As for the measurements carried out at 100 deg C, there was an increase in the thermal conductivity for the same BeO contents of 20% and 31%. These values as a percentage of increased conductivity were obtained in relation to the UO_2 pellets. (author)

  8. Thermal analysis of thermo-gravimetric measurements of spent nuclear fuel oxidation rates

    International Nuclear Information System (INIS)

    Cramer, E.R.

    1997-01-01

    A detailed thermal analysis was completed of the sample temperatures in the Thermo-Gravimetric Analysis (TGA) system used to measure irradiated N Reactor fuel oxidation rates. Sample temperatures during the oxidation process did not show the increase which was postulated as a result of the exothermic reactions. The analysis shows the axial conduction of heat in the sample holder effectively removes the added heat and only a very small, i.e., <10 C, increase in temperature is calculated. A room temperature evaporation test with water showed the sample thermocouple sensitivity to be more than adequate to account for a temperature change of approximately 5 C. Therefore, measured temperatures in the TGA are within approximately 10 C of the actual sample temperatures and no adjustments to reported data to account for the heat input from the oxidation process are necessary

  9. Thermal performance of fresh mixed-oxide fuel in a fast flux LMR [liquid metal reactor

    International Nuclear Information System (INIS)

    Ethridge, J.L.; Baker, R.B.

    1985-01-01

    A test was designed and irradiated to provide power-to-melt (heat generation rate necessary to initiate centerline fuel melting) data for fresh mixed-oxide UO 2 -PuO 2 fuel irradiated in a fast neutron flux under prototypic liquid metal reactor (LMR) conditions. The fuel pin parameters were selected to envelope allowable fabrication ranges and address mass production of LMR fuel using sintered-to-size techniques. The test included fuel pins with variations in fabrication technique, pellet density, fuel-to-cladding gap, Pu concentration, and fuel oxygen-to-metal ratios. The resulting data base has reestablished the expected power-to-melt in mixed-oxide fuels during initial reactor startup when the fuel temperatures are expected to be the highest. Calibration of heat transfer models of fuel pin performance codes with these data are providing more accurate capability for predicting steady-state thermal behavior of current and future mixed-oxide LMR fuels

  10. Thermal and oxidative stability of the Ocimum basilicum L. essential oil/β-cyclodextrin supramolecular system

    Directory of Open Access Journals (Sweden)

    Daniel I. Hădărugă

    2014-11-01

    Full Text Available Ocimum basilicum L. essential oil and its β-cyclodextrin (β-CD complex have been investigated with respect to their stability against the degradative action of air/oxygen and temperature. This supramolecular system was obtained by a crystallization method in order to achieve the equilibrium of complexed–uncomplexed volatile compounds in an ethanol/water solution at 50 °C. Both the raw essential oil and its β-CD complex have been subjected to thermal and oxidative degradation conditions in order to evaluate the protective capacity of β-CD. The relative concentration of the O. basilicum L. essential oil compounds, as determined by GC–MS, varies accordingly with their sensitivity to the thermal and/or oxidative degradation conditions imposed. Furthermore, the relative concentration of the volatile O. basilicum L. compounds found in the β-CD complex is quite different in comparison with the raw material. An increase of the relative concentration of linalool oxide from 0.3% to 1.1%, in addition to many sesquiterpene oxides, has been observed. β-CD complexation of the O. basilicum essential oil modifies the relative concentration of the encapsulated volatile compounds. Thus, linalool was better encapsulated in β-CD, while methylchavicol (estragole was encapsulated in β-CD at a concentration close to that of the raw essential oil. Higher relative concentrations from the degradation of the oxygenated compounds such as linalool oxide and aromadendren oxide were determined in the raw O. basilicum L. essential oil in comparison with the corresponding β-CD complex. For the first time, the protective capability of natural β-CD for labile basil essential oil compounds has been demonstrated.

  11. Thermal and oxidative stability of the Ocimum basilicum L. essential oil/β-cyclodextrin supramolecular system.

    Science.gov (United States)

    Hădărugă, Daniel I; Hădărugă, Nicoleta G; Costescu, Corina I; David, Ioan; Gruia, Alexandra T

    2014-01-01

    Ocimum basilicum L. essential oil and its β-cyclodextrin (β-CD) complex have been investigated with respect to their stability against the degradative action of air/oxygen and temperature. This supramolecular system was obtained by a crystallization method in order to achieve the equilibrium of complexed-uncomplexed volatile compounds in an ethanol/water solution at 50 °C. Both the raw essential oil and its β-CD complex have been subjected to thermal and oxidative degradation conditions in order to evaluate the protective capacity of β-CD. The relative concentration of the O. basilicum L. essential oil compounds, as determined by GC-MS, varies accordingly with their sensitivity to the thermal and/or oxidative degradation conditions imposed. Furthermore, the relative concentration of the volatile O. basilicum L. compounds found in the β-CD complex is quite different in comparison with the raw material. An increase of the relative concentration of linalool oxide from 0.3% to 1.1%, in addition to many sesquiterpene oxides, has been observed. β-CD complexation of the O. basilicum essential oil modifies the relative concentration of the encapsulated volatile compounds. Thus, linalool was better encapsulated in β-CD, while methylchavicol (estragole) was encapsulated in β-CD at a concentration close to that of the raw essential oil. Higher relative concentrations from the degradation of the oxygenated compounds such as linalool oxide and aromadendren oxide were determined in the raw O. basilicum L. essential oil in comparison with the corresponding β-CD complex. For the first time, the protective capability of natural β-CD for labile basil essential oil compounds has been demonstrated.

  12. Comparative evaluation of thermal oxidative decomposition for oil-plant residues via thermogravimetric analysis: Thermal conversion characteristics, kinetics, and thermodynamics.

    Science.gov (United States)

    Chen, Jianbiao; Wang, Yanhong; Lang, Xuemei; Ren, Xiu'e; Fan, Shuanshi

    2017-11-01

    Thermal oxidative decomposition characteristics, kinetics, and thermodynamics of rape straw (RS), rapeseed meal (RM), camellia seed shell (CS), and camellia seed meal (CM) were evaluated via thermogravimetric analysis (TGA). TG-DTG-DSC curves demonstrated that the combustion of oil-plant residues proceeded in three stages, including dehydration, release and combustion of organic volatiles, and chars oxidation. As revealed by combustion characteristic parameters, the ignition, burnout, and comprehensive combustion performance of residues were quite distinct from each other, and were improved by increasing heating rate. The kinetic parameters were determined by Coats-Redfern approach. The results showed that the most possible combustion mechanisms were order reaction models. The existence of kinetic compensation effect was clearly observed. The thermodynamic parameters (ΔH, ΔG, ΔS) at peak temperatures were calculated through the activated complex theory. With the combustion proceeding, the variation trends of ΔH, ΔG, and ΔS for RS (RM) similar to those for CS (CM). Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Non-Parametric Kinetic (NPK Analysis of Thermal Oxidation of Carbon Aerogels

    Directory of Open Access Journals (Sweden)

    Azadeh Seifi

    2017-05-01

    Full Text Available In recent years, much attention has been paid to aerogel materials (especially carbon aerogels due to their potential uses in energy-related applications, such as thermal energy storage and thermal protection systems. These open cell carbon-based porous materials (carbon aerogels can strongly react with oxygen at relatively low temperatures (~ 400°C. Therefore, it is necessary to evaluate the thermal performance of carbon aerogels in view of their energy-related applications at high temperatures and under thermal oxidation conditions. The objective of this paper is to study theoretically and experimentally the oxidation reaction kinetics of carbon aerogel using the non-parametric kinetic (NPK as a powerful method. For this purpose, a non-isothermal thermogravimetric analysis, at three different heating rates, was performed on three samples each with its specific pore structure, density and specific surface area. The most significant feature of this method, in comparison with the model-free isoconversional methods, is its ability to separate the functionality of the reaction rate with the degree of conversion and temperature by the direct use of thermogravimetric data. Using this method, it was observed that the Nomen-Sempere model could provide the best fit to the data, while the temperature dependence of the rate constant was best explained by a Vogel-Fulcher relationship, where the reference temperature was the onset temperature of oxidation. Moreover, it was found from the results of this work that the assumption of the Arrhenius relation for the temperature dependence of the rate constant led to over-estimation of the apparent activation energy (up to 160 kJ/mol that was considerably different from the values (up to 3.5 kJ/mol predicted by the Vogel-Fulcher relationship in isoconversional methods

  14. First-principles calculations of orientation dependence of Si thermal oxidation based on Si emission model

    Science.gov (United States)

    Nagura, Takuya; Kawachi, Shingo; Chokawa, Kenta; Shirakawa, Hiroki; Araidai, Masaaki; Kageshima, Hiroyuki; Endoh, Tetsuo; Shiraishi, Kenji

    2018-04-01

    It is expected that the off-state leakage current of MOSFETs can be reduced by employing vertical body channel MOSFETs (V-MOSFETs). However, in fabricating these devices, the structure of the Si pillars sometimes cannot be maintained during oxidation, since Si atoms sometimes disappear from the Si/oxide interface (Si missing). Thus, in this study, we used first-principles calculations based on the density functional theory, and investigated the Si emission behavior at the various interfaces on the basis of the Si emission model including its atomistic structure and dependence on Si crystal orientation. The results show that the order in which Si atoms are more likely to be emitted during thermal oxidation is (111) > (110) > (310) > (100). Moreover, the emission of Si atoms is enhanced as the compressive strain increases. Therefore, the emission of Si atoms occurs more easily in V-MOSFETs than in planar MOSFETs. To reduce Si missing in V-MOSFETs, oxidation processes that induce less strain, such as wet or pyrogenic oxidation, are necessary.

  15. Thermally evaporated mechanically hard tin oxide thin films for opto-electronic apllications

    International Nuclear Information System (INIS)

    Tripathy, Sumanta K.; Rajeswari, V. P.

    2014-01-01

    Tungsten doped tin oxide (WTO) and Molybdenum doped tin oxide (MoTO) thin film were deposited on corn glass by thermal evaporation method. The films were annealed at 350°C for one hour. Structural analysis using Xray diffraction data shows both the films are polycrystalline in nature with monoclinic structure of tin oxide, Sn 3 O 4 , corresponding to JCPDS card number 01-078-6064. SEM photograph showed that both the films have spherical grains with size in the range of 20–30 nm. Compositional analysis was carried out using EDS which reveals the presence of Sn, O and the dopant Mo/W only thereby indicating the absence of any secondary phase in the films. The films are found to contain nearly 6 wt% of Mo, 8 wt% of W as dopants respectively. The transmission pattern for both the films in the spectral range 200 – 2000 nm shows that W doping gives a transparency of nearly 80% from 380 nm onwards while Mo doping has less transparency of 39% at 380nm. Film hardness measurement using Triboscope shows a film hardness of about 9–10 GPa for both the films. It indicates that W or M doping in tin oxide provides the films the added advantage of withstanding the mechanical wear and tear due to environmental fluctuations By optimizing the optical and electrical properties, W/Mo doped tin oxide films may be explored as window layers in opto-electronic applications such as solar cells

  16. Sandia's severe human body Electrostatic Discharge Tester (SSET)

    International Nuclear Information System (INIS)

    Barnum, J.R.

    1991-01-01

    This paper reports that the Electromagnetic Testing Division at Sandia National Laboratories (SNL) has developed a simulator to replicate a severe human body electrostatic discharge event. This simulator is referred to as Sandia's Severe Human Body Electrostatic Discharge Tester (SSET). The SSET is configured as a coaxial transmission line, which allows control of parasitic inductance and capacitance to achieve the desired waveform signature, and operates reliably at voltages up to 35 kV. It is constructed from off-the-shelf or easily fabricated components and costs approximately $750 for materials, not including the power supply. The output is very repeatable and provides good simulation fidelity of a severe human body discharge

  17. Studying the processes relating to oxidation of organic substances contained in the coolant of thermal and nuclear power stations

    Science.gov (United States)

    Khodyrev, B. N.; Krichevtsov, A. L.; Sokolyuk, A. A.

    2010-07-01

    A radical-chain mechanism governing thermal-oxidation destruction of organic substances contained in the coolant of thermal and nuclear power stations is considered. Hypotheses on the chemical nature of antioxidation properties of amines are presented. Theoretical conjectures about the fundamental processes through which protective amine films are formed on the surface of metals are suggested.

  18. Comparison of different test methods to assess thermal stresses of metal oxide surge arresters under pollution conditions

    International Nuclear Information System (INIS)

    Bargigia, A.; de Nigris, M.; Pigini, A.; Sironi, A.

    1992-01-01

    The report deals with the research conducted by ENEL, the Italian Electricity Board, to assess the performance of zinc oxide surge arresters under pollution condition, with special reference to the consequent thermal stress on internal active parts which can affect the energy handling capabality of the arrester and may lead, in particular conditions, even to thermal runaway

  19. A lumped model of venting during thermal runaway in a cylindrical lithium cobalt oxide lithium-ion cell

    DEFF Research Database (Denmark)

    Coman, Paul Tiberiu; Rayman, Sean; White, Ralph

    2016-01-01

    This paper presents a mathematical model built for analyzing the intricate thermal behavior of a 18650 LCO (Lithium Cobalt Oxide) battery cell during thermal runaway when venting of the electrolyte and contents of the jelly roll (ejecta) is considered. The model consists of different ODEs (Ordinary...

  20. Gadolinium oxide coated fully depleted silicon-on-insulator transistors for thermal neutron dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Vitale, Steven A., E-mail: steven.vitale@ll.mit.edu; Gouker, Pascale M.

    2013-09-01

    Fully depleted silicon-on-insulator transistors coated with gadolinium oxide are shown to be effective thermal neutron dosimeters. The theoretical neutron detection efficiency is calculated to be higher for Gd{sub 2}O{sub 3} than for other practical converter materials. Proof-of-concept dosimeter devices were fabricated and tested during thermal neutron irradiation. The transistor current changes linearly with neutron dose, consistent with increasing positive charge in the SOI buried oxide layer generated by ionization from high energy {sup 157}Gd(n,γ){sup 158}Gd conversion electrons. The measured neutron sensitivity is approximately 1/6 the maximum theoretical value, possibly due to electron–hole recombination or conversion electron loss in interconnect wiring above the transistors. -- Highlights: • A novel Gd{sub 2}O{sub 3} coated FDSOI MOSFET thermal neutron dosimeter is presented. • Dosimeter can detect charges generated from {sup 157}Gd(n,γ){sup 158}Gd conversion electrons. • Measured neutron sensitivity is comparable to that calculated theoretically. • Dosimeter requires zero power during operation, enabling new application areas.

  1. Thermal oxidation of InP in the presence of nitrates and sulfates of the 4-th group

    International Nuclear Information System (INIS)

    Mittova, I.Ya.; Shchukarev, A.V.; Soshnikov, V.V.; Kashkarov, V.M.

    1999-01-01

    Kinetics and thermal oxidation of indium phosphide were investigated in gas phase of 4 group metal (lead and zirconium) salts. These compound promotors were determined to accelerate oxidation. The mechanism of the effect of promoter cation and anion constituents on formation of the resultant heterostructure were discussed [ru

  2. Tungsten oxide thin films grown by thermal evaporation with high resistance to leaching

    Energy Technology Data Exchange (ETDEWEB)

    Correa, Diogo S. [Universidade Federal de Pelotas (UFPel), RS (Brazil). Centro de Ciencias Quimicas, Farmaceuticas e de Alimentos; Pazinato, Julia C.O.; Freitas, Mauricio A. de; Radtke, Claudio; Garcia, Irene T.S., E-mail: irene@iq.ufrgs.br [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Instituto de Quimica; Dorneles, Lucio S. [Universidade Federal de Santa Maria (UFSM), RS (Brazil). Centro de Ciencias Naturais e Exatas

    2014-05-15

    Tungsten oxides show different stoichiometries, crystal lattices and morphologies. These characteristics are important mainly when they are used as photocatalysts. In this work tungsten oxide thin films were obtained by thermal evaporation on (100) silicon substrates covered with gold and heated at 350 and 600 °C, with different deposition times. The stoichiometry of the films, morphology, crystal structure and resistance to leaching were characterized through X-ray photoelectron spectroscopy, micro-Raman spectroscopy, scanning and transmission electron microscopy, X-ray diffractometry, Rutherford backscattering spectrometry and O{sup 16} (α,α')O{sup 16} resonant nuclear reaction. Films obtained at higher temperatures show well-defined spherical nanometric structure; they are composed of WO{sub 3.1} and the presence of hydrated tungsten oxide was also observed. The major crystal structure observed is the hexagonal. Thin films obtained through thermal evaporation present resistance to leaching in aqueous media and excellent performance as photocatalysts, evaluated through the degradation of the methyl orange dye. (author)

  3. Thermal oxidation effect on structural and optical properties of heavily doped phosphorus polycrystalline silicon films

    Energy Technology Data Exchange (ETDEWEB)

    Birouk, B.; Madi, D. [Universite de Jijel, Laboratoire d' Etudes et de Modelisation en Electrotechnique (LAMEL), Cite Ouled Aissa, BP 98, Jijel (Algeria)

    2011-08-15

    The study reported in this paper contributes to better understanding the thermal oxidation effect on structural and optical properties of polycrystalline silicon heavily in situ P-LPCVD films. The deposits, doped at levels 3 x 10{sup 19} and 1.6 x 10{sup 20} cm{sup -3}, have been elaborated from silane decomposition (400 mTorrs, 605 C) on monosilicon substrate oriented left angle 111 right angle. The thermal oxidation was performed at temperatures: 850 C during 1 hour, 1000, 1050, and 1100 C during 15 minutes. The XRD spectra analysis pointed out significant left angle 111 right angle texture evolution, while in the case of left angle 220 right angle and left angle 311 right angle textures, the intensities are practically invariant (variations fall in the uncertainty intervals). The optical characterizations showed that refractive index and absorption coefficient are very sensitive to the oxidation treatment, mainly when the doping level is not very high. We think that atomic oxygen acts as defects passivating agent leading to carriers' concentration increasing. Besides, the optical behavior is modeled in visible and near infrared, by a seven-term polynomial function n {sup 2}=f({lambda} {sup 2}), with alternate signs, instead of theoretically unlimited terms number from Drude's model. It has been shown that fitting parameters fall on Gaussian curves like they do in the theoretical model. (orig.)

  4. Thermal Oxidation of Tail Gases from the Production of Oil-furnace Carbon Black

    Directory of Open Access Journals (Sweden)

    Bosak, Z.

    2009-01-01

    Full Text Available This paper describes the production technology of oil-furnace carbon black, as well as the selected solution for preventing the emissions of this process from contaminating the environment.The products of industrial oil-furnace carbon black production are different grades of carbon black and process tail gases. The qualitative composition of these tail gases during the production of oil-furnace carbon black are: carbon(IV oxide, carbon(II oxide, hydrogen, methane, hydrogen sulfide, nitrogen, oxygen, and water vapor.The quantitative composition and lower caloric value of process tail gases change depending on the type of feedstock used in the production, as well as the type of process. The lower caloric value of process tail gases is relatively small with values ranging between 1500 and 2300 kJ m–3.In the conventional production of oil-furnace carbon black, process tail gases purified from carbon black dust are freely released into the atmosphere untreated. In this manner, the process tail gases pollute the air in the town of Kutina, because their quantitative values are much higher than the prescribed emissions limits for hydrogen sulfide and carbon(II oxide. A logical solution for the prevention of such air pollution is combustion of the process tail gases, i. e. their thermal oxidation. For this purpose, a specially designed flare system has been developed. Consuming minimum amounts of natural gas needed for oxidation, the flare system is designed to combust low caloric process tail gases with 99 % efficiency. Thus, the toxic and flammable components of the tail gases (hydrogen sulfide, hydrogen, carbon(II oxide, methane and other trace hydrocarbons would be transformed into environmentally acceptable components (sulfur(IV oxide, water, carbon(IV oxide and nitrogen(IV oxide, which are in compliance with the emissions limit values prescribed by law.Proper operation of this flare system in the production of oil-furnace carbon black would solve

  5. Portable tester for determining gas content within a core sample

    Science.gov (United States)

    Garcia, F. Jr.; Schatzel, S.J.

    1998-04-21

    A portable tester is provided for reading and displaying the pressure of a gas released from a rock core sample stored within a sealed container and for taking a sample of the released pressurized gas for chemical analysis thereof for subsequent use in a modified direct method test which determines the volume of gas and specific type of gas contained within the core sample. The portable tester includes a pair of low and high range electrical pressure transducers for detecting a gas pressure; a pair of low and high range display units for displaying the pressure of the detected gas; a selector valve connected to the low and high range pressure transducers and a selector knob for selecting gas flow to one of the flow paths; control valve having an inlet connection to the sealed container; and outlets connected to: a sample gas canister, a second outlet port connected to the selector valve means for reading the pressure of the gas from the sealed container to either the low range or high range pressure transducers, and a connection for venting gas contained within the sealed container to the atmosphere. A battery is electrically connected to and supplies the power for operating the unit. The pressure transducers, display units, selector and control valve means and the battery is mounted to and housed within a protective casing for portable transport and use. 5 figs.

  6. Test strategies for industrial testers for converter controls equipment

    International Nuclear Information System (INIS)

    Oleniuk, P.; Kasampalis, V.; Cosmo, M. Di; Nisbet, D.; Todd, B.; Uznański, S.

    2017-01-01

    Power converters and their controls electronics are key elements for the operation of the CERN accelerator complex, having a direct impact on its availability. To prevent early-life failures and provide means to verify electronics, a set of industrial testers is used throughout the converters controls electronics' life cycle. The roles of the testers are to validate mass production during the manufacturing phase and to provide means to diagnose and repair failed modules that are brought back from operation. In the converter controls electronics section of the power converters group in the technology department of CERN (TE/EPC/CCE), two main test platforms have been adopted: a PXI platform for mixed analogue-digital functional tests and a JTAG Boundary-Scan platform for digital interconnection and functional tests. Depending on the functionality of the device under test, the appropriate test platforms are chosen. This paper is a follow-up to results presented at the TWEPP 2015 conference, adding the boundary scan test platform and the first results from exploitation of the test system. This paper reports on the test software, hardware design and test strategy applied for a number of devices that has resulted in maximizing test coverage and minimizing test design effort.

  7. submitter Test strategies for industrial testers for converter controls equipment

    CERN Document Server

    Oleniuk, P; Kasampalis, V; Nisbet, D; Todd, B; Uznański, S

    2017-01-01

    Power converters and their controls electronics are key elements for the operation of the CERN accelerator complex, having a direct impact on its availability. To prevent early-life failures and provide means to verify electronics, a set of industrial testers is used throughout the converters controls electronics' life cycle. The roles of the testers are to validate mass production during the manufacturing phase and to provide means to diagnose and repair failed modules that are brought back from operation. In the converter controls electronics section of the power converters group in the technology department of CERN (TE/EPC/CCE), two main test platforms have been adopted: a PXI platform for mixed analogue-digital functional tests and a JTAG Boundary-Scan platform for digital interconnection and functional tests. Depending on the functionality of the device under test, the appropriate test platforms are chosen. This paper is a follow-up to results presented at the TWEPP 2015 conference, adding the boundary s...

  8. Changes in Acylglycerols composition, quality characteristics and in vivo effects of dietary pumpkin seed oil upon thermal oxidation

    Science.gov (United States)

    Zeb, Alam; Ahmad, Sultan

    2017-07-01

    This study was aimed to determine the acylglycerols composition, quality characteristics and protective role of dietary pumpkin seed oil in rabbits. Pumpkin seed oil was thermally oxidized and analyzed for quality characteristics and acylglycerols composition using reversed phase high performance liquid chromatography with diode array detection (HPLC-DAD). Oxidized and un-oxidized oil samples were fed to the rabbits in different doses for two weeks. The changes in the serum biochemistry, hematology, and liver histology were studied. The levels of quality parameters such peroxide value (PV), anisidine value (AV), total phenolic contents (TPC), thiobarbituric acid reactive substances (TBARS), conjugated dienes (CD) and conjugated trienes (CT) significantly increased with thermal treatment. HPLC analyses revealed ten individual triacylglycerols (TAGs), total di-acylglycerols (DAGs), mono-acylglycerols (MAGs), and total oxidized TAGs. Trilinolein (LLL), 1-oleoyl-2,3-dilinolinoyl glycerol (OLL), triolein (OOO) and 1,2-distearoyl-3-palmitoyl glycerol (SSP) were present in higher amounts and decreased with thermal treatment. Animal's studies showed that oxidized oils decreased the whole body weight, which was ameliorated by the co-administration of un-oxidized oils. The levels of serum biochemical parameters were improved by co-administration of pumpkin seed oils. There were no significant effects of both oxidized and un-oxidized pumpkin seed oil on the hematological and histological parameters of rabbits. In conclusion, nutritionally important triacylglycerols were present in pumpkin seed oil with protective role against the toxicity of its corresponding oxidized oils.

  9. Changes in Acylglycerols Composition, Quality Characteristics and In vivo Effects of Dietary Pumpkin Seed Oil upon Thermal Oxidation

    Directory of Open Access Journals (Sweden)

    Alam Zeb

    2017-07-01

    Full Text Available This study was aimed to determine the acylglycerols composition, quality characteristics, and protective role of dietary pumpkin seed oil (PSO in rabbits. PSO was thermally oxidized and analyzed for quality characteristics and acylglycerols composition using reversed phase high performance liquid chromatography with diode array detection (HPLC-DAD. Oxidized and un-oxidized oil samples were fed to the rabbits in different doses for 2 weeks. The changes in the serum biochemistry, hematology, and liver histology were studied. The levels of quality parameters such peroxide value (PV, anisidine value (AV, total phenolic contents (TPC, thiobarbituric acid reactive substances (TBARS, conjugated dienes (CD and conjugated trienes (CT significantly increased with thermal treatment. HPLC analyses revealed 10 individual triacylglycerols (TAGs, total di-acylglycerols (DAGs, mono-acylglycerols (MAGs, and total oxidized TAGs. Trilinolein (LLL, 1-oleoyl-2,3-dilinolinoyl glycerol (OLL, triolein (OOO and 1,2-distearoyl-3-palmitoyl glycerol (SSP were present in higher amounts and decreased with thermal treatment. Animal's studies showed that oxidized oils decreased the whole body weight, which was ameliorated by the co-administration of un-oxidized oils. The levels of serum biochemical parameters were improved by co-administration of pumpkin seed oils. There were no significant effects of both oxidized and un-oxidized PSO on the hematological and histological parameters of rabbits. In conclusion, nutritionally important triacylglycerols were present in PSO with protective role against the toxicity of its corresponding oxidized oils.

  10. Thermally stimulated currents between 300 K and 800 K in beryllium oxide

    International Nuclear Information System (INIS)

    Martinelli, J.R.

    1979-01-01

    Thermally Stimulated Polarization/Depolarization Currents (ISPC/ISDC) have been measured in ceramic Beryllium Oxide in the temperature range RT-800 K. Specimens dc biased above RT show a Thermoelectret behaviour at RT. The thermal destruction of the thermoelectret state gives rise to a TSDC spectrum with at least three current maxima. Two contributions to the induced polarization are found: one volumetric uniform and another due to space charge formation. These polarizations are related to the impurity content (mainly Si and Al) as well as to the microstructure (average grain size, grain boundary distribution, pore distribution, glassy phases) of the ceramic specimens. Some mechanisms, based on Al 3+ - compensation vacancies and charge carriers transport via grain boundaries (through pore glassy phases) are proposed to explain the observed TSDC Spectra and the electrical conductivity results. (Author) [pt

  11. In-depth investigation of spin-on doped solar cells with thermally grown oxide passivation

    Directory of Open Access Journals (Sweden)

    Samir Mahmmod Ahmad

    Full Text Available Solar cell industrial manufacturing, based largely on proven semiconductor processing technologies supported by significant advancements in automation, has reached a plateau in terms of cost and efficiency. However, solar cell manufacturing cost (dollar/watt is still substantially higher than fossil fuels. The route to lowering cost may not lie with continuing automation and economies of scale. Alternate fabrication processes with lower cost and environmental-sustainability coupled with self-reliance, simplicity, and affordability may lead to price compatibility with carbon-based fuels. In this paper, a custom-designed formulation of phosphoric acid has been investigated, for n-type doping in p-type substrates, as a function of concentration and drive-in temperature. For post-diffusion surface passivation and anti-reflection, thermally-grown oxide films in 50–150-nm thickness were grown. These fabrication methods facilitate process simplicity, reduced costs, and environmental sustainability by elimination of poisonous chemicals and toxic gases (POCl3, SiH4, NH3. Simultaneous fire-through contact formation process based on screen-printed front surface Ag and back surface through thermally grown oxide films was optimized as a function of the peak temperature in conveyor belt furnace. Highest efficiency solar cells fabricated exhibited efficiency of ∼13%. Analysis of results based on internal quantum efficiency and minority carried measurements reveals three contributing factors: high front surface recombination, low minority carrier lifetime, and higher reflection. Solar cell simulations based on PC1D showed that, with improved passivation, lower reflection, and high lifetimes, efficiency can be enhanced to match with commercially-produced PECVD SiN-coated solar cells. Keywords: Crystalline Si solar cells, Phosphoric acid spin-on doping, Screen printing, Thermal oxide passivation

  12. Formation and Thermal Stability of Large Precipitates and Oxides in Titanium and Niobium Microalloyed Steel

    Institute of Scientific and Technical Information of China (English)

    ZHUO Xiao-jun; WOO Dae-hee; WANG Xin-hua; LEE Hae-geon

    2008-01-01

    As-cast CC slabs of microalloyed steels are prone to surface and sub-surface cracking. Precipitation phenomena in-itiated during solidification reduce ductility at high temperature. The unidirectional solidification unit is employed to sim-ulate the solidification process during continuous casting. Precipitation behavior and thermal stability are systemati-cally investigated. Samples of adding titanium and niobium to steels have been examined using field emission scanning electron microscope (FE-SEM), electron probe X-ray microanalyzer (EPMA), and transmission electron microscope (TEM). It has been found that the addition of titanium and niobium to high-strength low-alloyed (HSLA) steel resuited in undesirable large precipitation in the steels, i. e. , precipitation of large precipitates with various morphologies. The composition of the large precipitates has been determined. The effect of cooling rate on (Ti, Nb)(C, N) precipitate formation is investigated. With increasing the cooling rate, titanium-rich (Ti,Nb)(C, N) precipitates are transformed to niobium-rich (Ti,Nb)(C,N) precipitates. The thermal stability of these large precipitates and oxides have been assessed by carrying out various heat treatments such as holding and quenching from temperature at 800 and 1 200 ℃. It has been found that titanium-rich (Ti,Nb)(C,N) precipitate is stable at about 1 200 ℃ and niobi-um-rich (Ti,Nb)(C,N) precipitate is stable at about 800 ℃. After reheating at 1 200 ℃ for 1 h, (Ca, Mn)S and TiN are precipitated from Ca-Al oxide. However, during reheating at 800 ℃ for 1 h, Ca-Al-Ti oxide in specimens was stable. The thermodynamic calculation of simulating the thermal process is employed. The calculation results are in good agreement with the experimental results.

  13. Thermal-driven attachment of gold nanoparticles prepared with ascorbic acid onto indium tin oxide surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Aziz, Md. Abdul; Oyama, Munetaka, E-mail: oyama.munetaka.4m@kyoto-u.ac.jp [Kyoto University, Department of Material Chemistry, Graduate School of Engineering (Japan)

    2013-05-15

    Thermal-driven attachment of gold nanoparticles (AuNPs), of which size was less than 50 nm, onto the surfaces of indium tin oxide (ITO) is reported as a new phenomenon. This was permitted by preparing AuNPs via the reduction of hydrogen tetrachloroaurate (HAuCl{sub 4}) with ascorbic acid (AA). While the AuNPs prepared via the AA reduction sparsely attached on the surface of ITO even at room temperature, a heat-up treatment at ca. 75 Degree-Sign C caused denser attachment of AuNPs on ITO surfaces. The attached density and the homogeneity after the thermal treatment were better than those of AuNP/ITO prepared using 3-aminopropyl-trimethoxysilane linker molecules. The denser attachment was observed similarly both by the immersion of ITO samples after the preparations of AuNPs by AA and by the in situ preparation of AuNPs with AA together with ITO samples. Thus, it is considered that the thermal-driven attachment of AuNPs would occur after the formation of AuNPs in the aqueous solutions, not via the growth of AuNPs on ITO surfaces. The preparation of AuNPs with AA would be a key for the thermal-driven attachment because the same attachments were not observed for AuNPs prepared with citrate ions or commercially available tannic acid-capped AuNPs.

  14. Characteristics of phase-change materials containing oxide nano-additives for thermal storage.

    Science.gov (United States)

    Teng, Tun-Ping; Yu, Chao-Chieh

    2012-11-06

    In this study, the authors report the production of nanocomposite-enhanced phase-change materials (NEPCMs) using the direct-synthesis method by mixing paraffin with alumina (Al2O3), titania (TiO2), silica (SiO2), and zinc oxide (ZnO) as the experimental samples. Al2O3, TiO2, SiO2, and ZnO were dispersed into three concentrations of 1.0, 2.0, and 3.0 wt.%. Through heat conduction and differential scanning calorimeter experiments to evaluate the effects of varying concentrations of the nano-additives on the heat conduction performance and thermal storage characteristics of NEPCMs, their feasibility for use in thermal storage was determined. The experimental results demonstrate that TiO2 is more effective than the other additives in enhancing both the heat conduction and thermal storage performance of paraffin for most of the experimental parameters. Furthermore, TiO2 reduces the melting onset temperature and increases the solidification onset temperature of paraffin. This allows the phase-change heat to be applicable to a wider temperature range, and the highest decreased ratio of phase-change heat is only 0.46%, compared to that of paraffin. Therefore, this study demonstrates that TiO2, added to paraffin to form NEPCMs, has significant potential for enhancing the thermal storage characteristics of paraffin.

  15. Effects of thermal treatment on mineralogy and heavy metal behavior in iron oxide stabilized air pollution control residues

    DEFF Research Database (Denmark)

    Sørensen, Mette Abildgaard; Bender-Koch, C.; Starckpoole, M. M.

    2000-01-01

    Stabilization of air pollution control residues by coprecipitation with ferrous iron and subsequent thermal treatment (at 600 and 900 °C) has been examined as a means to reduce heavy metal leaching and to improve product stability. Changes in mineralogy and metal binding were analyzed using various...... analytical and environmental techniques. Ferrihydrite was formed initially but transformed upon thermal treatment to more stable and crystalline iron oxides (maghemite and hematite). For some metals leaching studies showed more substantial binding after thermal treatment, while other metals either....... Thermal treatment of the stabilized residues produced structures with an inherently better iron oxide stability. However, the concentration of metals in the leachate generally increased as a consequence of the decreased solubility of metals in the more stable iron oxide structure....

  16. Uniform photoresponse in thermally oxidized Ni and MoS2 heterostructures

    International Nuclear Information System (INIS)

    Luo, Wei; Peng, Gang; Wang, Fei; Miao, Feng; Zhang, Xue-Ao; Qin, Shiqiao

    2017-01-01

    Non-uniform photocurrent is usually generated at the overlapped region of the heterostructures, and its potential applications may be hindered by the spatial uniformity issue of the device photoresponse. Here, nearly a uniform photoresponse at the overlapped region of the thermally oxidized Ni and molybdenum disulphide (MoS 2 ) heterostructures is obtained. Further characterizations reveal that several nanometers Ni is rightly under the NiO x layer formed at the surface of the film in the oxidation process. The heterostructures based on layered MoS 2 /NiO x /Ni with highly conductive bottom Ni show a high uniform photoresponse with an external quantum efficiency (EQE) of 1.4% at 532 nm. Moreover, successful integration of multiple devices suggests a great priority for such a structure for highly integrated uniform photodetectors. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Effect of grain alignment on interface trap density of thermally oxidized aligned-crystalline silicon films

    Science.gov (United States)

    Choi, Woong; Lee, Jung-Kun; Findikoglu, Alp T.

    2006-12-01

    The authors report studies of the effect of grain alignment on interface trap density of thermally oxidized aligned-crystalline silicon (ACSi) films by means of capacitance-voltage (C-V) measurements. C-V curves were measured on metal-oxide-semiconductor (MOS) capacitors fabricated on ⟨001⟩-oriented ACSi films on polycrystalline substrates. From high-frequency C-V curves, the authors calculated a decrease of interface trap density from 2×1012to1×1011cm-2eV-1 as the grain mosaic spread in ACSi films improved from 13.7° to 6.5°. These results demonstrate the effectiveness of grain alignment as a process technique to achieve significantly enhanced performance in small-grained (⩽1μm ) polycrystalline Si MOS-type devices.

  18. Uniform photoresponse in thermally oxidized Ni and MoS{sub 2} heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Wei [College of Science, National University of Defense Technology, Changsha (China); National Laboratory of Solid State Microstructures, School of Physics, Nanjing University (China); Peng, Gang; Wang, Fei [College of Science, National University of Defense Technology, Changsha (China); Miao, Feng [National Laboratory of Solid State Microstructures, School of Physics, Nanjing University (China); Zhang, Xue-Ao; Qin, Shiqiao [College of Science, National University of Defense Technology, Changsha (China); State Key Laboratory of High Performance Computing, National University of Defense Technology, Changsha (China)

    2017-09-15

    Non-uniform photocurrent is usually generated at the overlapped region of the heterostructures, and its potential applications may be hindered by the spatial uniformity issue of the device photoresponse. Here, nearly a uniform photoresponse at the overlapped region of the thermally oxidized Ni and molybdenum disulphide (MoS{sub 2}) heterostructures is obtained. Further characterizations reveal that several nanometers Ni is rightly under the NiO{sub x} layer formed at the surface of the film in the oxidation process. The heterostructures based on layered MoS{sub 2}/NiO{sub x}/Ni with highly conductive bottom Ni show a high uniform photoresponse with an external quantum efficiency (EQE) of 1.4% at 532 nm. Moreover, successful integration of multiple devices suggests a great priority for such a structure for highly integrated uniform photodetectors. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Transient thermal effect, nonlinear refraction and nonlinear absorption properties of graphene oxide sheets in dispersion.

    Science.gov (United States)

    Zhang, Xiao-Liang; Liu, Zhi-Bo; Li, Xiao-Chun; Ma, Qiang; Chen, Xu-Dong; Tian, Jian-Guo; Xu, Yan-Fei; Chen, Yong-Sheng

    2013-03-25

    The nonlinear refraction (NLR) properties of graphene oxide (GO) in N, N-Dimethylformamide (DMF) was studied in nanosecond, picosecond and femtosecond time regimes by Z-scan technique. Results show that the dispersion of GO in DMF exhibits negative NLR properties in nanosecond time regime, which is mainly attributed to transient thermal effect in the dispersion. The dispersion also exhibits negative NLR in picosecond and femtosecond time regimes, which are arising from sp(2)- hybridized carbon domains and sp(3)- hybridized matrix in GO sheets. To illustrate the relations between NLR and nonlinear absorption (NLA), NLA properties of the dispersion were also studied in nanosecond, picosecond and femtosecond time regimes.

  20. Thermally oxidized aluminum as catalyst-support layer for vertically aligned single-walled carbon nanotube growth using ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Azam, Mohd Asyadi, E-mail: asyadi@jaist.ac.jp [School of Materials Science, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan); Fujiwara, Akihiko [Research and Utilization Division, Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1, Kouto, Sayo-cho, Sayo, Hyogo 679-5198 (Japan); Shimoda, Tatsuya [School of Materials Science, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa 923-1292 (Japan)

    2011-11-01

    Characteristics and role of Al oxide (Al-O) films used as catalyst-support layer for vertical growth of single-walled carbon nanotubes (SWCNTs) were studied. EB-deposited Al films (20 nm) were thermally oxidized at 400 deg. C (10 min, static air) to produce the most appropriate surface structure of Al-O. Al-O catalyst-support layers were characterized using various analytical measurements, i.e., atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and spectroscopy ellipsometry (SE). The thermally oxidized Al-O has a highly roughened surface, and also has the most suitable surface chemical states compared to other type of Al-O support layers. We suggest that the surface of thermally oxidized Al-O characterized in this work enhanced Co catalyst activity to promote the vertically aligned SWCNT growth.

  1. Thermal catalytic oxidation of octachloronaphthalene over anatase TiO2 nanomaterial and its hypothesized mechanism

    Science.gov (United States)

    Su, Guijin; Li, Qianqian; Lu, Huijie; Zhang, Lixia; Huang, Linyan; Yan, Li; Zheng, Minghui

    2015-12-01

    As an environmentally-green technology, thermal catalytic oxidation of octachloronaphthalene (CN-75) over anatase TiO2 nanomaterials was investigated at 300 °C. A wide range of oxidation intermediates, which were investigated using various techniques, could be of three types: naphthalene-ring, single-benzene-ring, and completely ring-opened products. Reactive oxygen species on anatase TiO2 surface, such as O2-• and O2-, contributed to oxidative degradation. Based on these findings, a novel oxidation degradation mechanism was proposed. The reaction at (101) surface of anatase TiO2 was used as a model. The naphthalene-ring oxidative products with chloronaphthols and hydroxyl-pentachloronaphthalene-dione, could be formed via attacking the carbon of naphthalene ring at one or more positions by nucleophilic O2-. Lateral cleavage of the naphthalene ring at different C1-C10 and C4-C9, C1-C2 and C4-C9, C1-C2 or and C3-C4 bond positions by electrophilic O2-• could occur. This will lead to the formation of tetrachlorophenol, tetrachloro-benzoic acid, tetrachloro-phthalaldehyde, and tetrachloro-acrolein-benzoic acid, partially with further transformation into tetrachlorobenzene-dihydrodiol and tetrachloro-salicylic acid. Unexpectedly, the symmetric half section of CN-75 could be completely remained with generating the intricate oxidative intermediates characteristically containing tetrachlorobenzene structure. Complete cleavage of naphthalene ring could produce the ring-opened products, such as formic and acetic acids.

  2. Air, aqueous and thermal stabilities of Ce3+ ions in cerium oxide nanoparticle layers with substrates

    KAUST Repository

    Naganuma, Tamaki

    2014-01-01

    Abundant oxygen vacancies coexisting with Ce3+ ions in fluorite cerium oxide nanoparticles (CNPs) have the potential to enhance catalytic ability, but the ratio of unstable Ce3+ ions in CNPs is typically low. Our recent work, however, demonstrated that the abundant Ce3+ ions created in cerium oxide nanoparticle layers (CNPLs) by Ar ion irradiation were stable in air at room temperature. Ce valence states in CNPs correlate with the catalytic ability that involves redox reactions between Ce3+ and Ce4+ ions in given application environments (e.g. high temperature in carbon monoxide gas conversion and immersion conditions in biomedical applications). To better understand the mechanism by which Ce3+ ions achieve stability in CNPLs, we examined (i) extra-long air-stability, (ii) thermal stability up to 500 °C, and (iii) aqueous stability of Ce 3+ ions in water, buffer solution and cell culture medium. It is noteworthy that air-stability of Ce3+ ions in CNPLs persisted for more than 1 year. Thermal stability results showed that oxidation of Ce 3+ to Ce4+ occurred at 350 °C in air. Highly concentrated Ce3+ ions in ultra-thin CNPLs slowly oxidized in water within 1 day, but stability was improved in the cell culture medium. Ce 3+ stability of CNPLs immersed in the medium was associated with phosphorus adsorption on the Ce3+ sites. This study also illuminates the potential interaction mechanisms of stable Ce3+ ions in CNPLs. These findings could be utilized to understand catalytic mechanisms of CNPs with abundant oxygen vacancies in their application environments. © The Royal Society of Chemistry 2014.

  3. Rapid and tunable selective adsorption of dyes using thermally oxidized nanodiamond.

    Science.gov (United States)

    Molavi, Hossein; Shojaei, Akbar; Pourghaderi, Alireza

    2018-03-27

    In the present study, capability of nanodiamond (ND) for the adsorption of anionic (methyl orange, MO) and cationic (methylene blue, MB) dyes from aqueous solution was investigated. Employing fourier transform infrared (FTIR) spectroscopy, Boehm titration method and zeta potential, it was found that the simple thermal oxidation of ND at 425 °C, increased the content of carboxylic acid of ND and accordingly the zeta potential of ND decreased considerably. Therefore, a series of oxidized NDs (OND) at various oxidation times and as-received untreated ND (UND) was used as adsorbents of MO and MB. The adsorption experiments exhibited that UND had large adsorption capacity, very fast adsorption kinetics and excellent selectivity for MO over MB. These results suggested that the adsorption tendency of UND toward anionic MO dye followed not only by electrostatic interactions but also via the chemical interaction caused by the strong hydrogen bond between the sulfonate groups of MO and the oxygen containing groups on the surface of UND. In contrast, ONDs exhibited higher adsorption capacity for cationic MB whose tendency toward MB increased by increasing the thermal oxidation time due to the promotion of the negative charge on the surface of OND leading to the higher electrostatic attraction. The adsorption rate of MB on ONDs was also very high. Kinetics data was well fitted with the pseudo- second-order model for most of the adsorbents. The adsorption selectivity analysis revealed that ONDs displayed more adsorption capacity for MB compared with MO which was also attributed to high electrostatic interactions of cationic dye with negative charges of ONDs. Finally, the release behavior of NDs was also demonstrated after soaking in ethanol and acetone. Copyright © 2018 Elsevier Inc. All rights reserved.

  4. The effect of thermal oxidation on the luminescence properties of nanostructured silicon.

    Science.gov (United States)

    Liu, Lijia; Sham, Tsun-Kong

    2012-08-06

    Herein is reported a detailed study of the luminescence properties of nanostructured Si using X-ray excited optical luminescence (XEOL) in combination with X-ray absorption near-edge structures (XANES). P-type Si nanowires synthesized via electroless chemical etching from Si wafers of different doping levels and porous Si synthesized using electrochemical method are examined under X-ray excitation across the Si K-, L(3,2) -, and O K-edges. It is found that while as-prepared Si nanostructures are weak light emitters, intense visible luminescence is observed from thermally oxidized Si nanowires and porous Si. The luminescence mechanism of Si upon oxidation is investigated by oxidizing nanostructured Si at different temperatures. Interestingly, the two luminescence bands observed show different response with the variation of absorption coefficient upon Si and O core-electron excitation in elemental silicon and silicon oxide. A correlation between luminescence properties and electronic structures is thus established. The implications of the finding are discussed in terms of the behavior of the oxygen deficient center (OCD) and non-bridging oxygen hole center (NBOHC). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. The kinetics and properties of thermal oxidation of silicon in TCA-O/sub 2/

    International Nuclear Information System (INIS)

    Ahmed, W.; Ahmed, E.

    1993-01-01

    The oxidation of silicon using dry O/sub 2/ is now well established as a key process for the fabrication of electronic devices in the semiconductor industry. However, this process is complicated by its sensitivity to impurities which reduce device yields. HCl can be added to O/sub 2/ to remove these impurities but due to its highly corrosive nature a safer and cleaner alternative such as trichloroethane (TCA) is desirable. In this paper, the thermal oxidation of silicon using a mixture of TCA-O/sub 2/ has been investigated in a large scale industrial system. The growth kinetics and the properties of these films have been studies and compared to oxides produced from dry 2. The addition of TCA generates HCl in situ, enhances the oxidation rate by approximately 54% nd improves the electrical properties. It was found that a 1 mol.% mixture gives the optimum process. An analysis of the data suggests that a liner parabolic growth model is applicable and provides a valuable insight into the physical phenomena governing this important process. (author)

  6. Efficient electrocatalytic performance of thermally exfoliated reduced graphene oxide-Pt hybrid

    Energy Technology Data Exchange (ETDEWEB)

    Antony, Rajini P., E-mail: raji.anna@gmail.com; Preethi, L.K.; Gupta, Bhavana; Mathews, Tom, E-mail: tom@igcar.gov.in; Dash, S.; Tyagi, A.K.

    2015-10-15

    Highlights: • Synthesis of Pt–RGO nanohybrids of very high electrochemically active surface area. • Electrocatalytic activity-cum-stability: ∼10 times that of commercial Pt-C catalyst. • TEM confirms narrow size distribution and excellent dispersion of Pt nanoparticles. • SAED and XRD indicate (1 1 1) orientation of Pt nanoparticles. • Methanol oxidation EIS reveal decrease in charge transfer resistance with potential - Abstract: High quality thermally exfoliated reduced graphene oxide (RGO) nanosheets decorated with platinum nanocrystals have been synthesized using a simple environmentally benign process. The electrocatalytic behaviour of the Pt–RGO nanohybrid for methanol oxidation was studied using cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy. High resolution transmission electron microscopy shows uniform dispersion of Pt nanoparticles of ∼2–4 nm size. X-ray diffraction and selected area diffraction studies reveal (1 1 1) orientation of the platinum nanoparticles. The cyclic voltammetry and chronoamperometry results indicate higher catalytic activity and stability for Pt–RGO compared to commercial Pt-C. The electrochemical active surface area of Pt–RGO (52.16 m{sup 2}/g) is found to be 1.5 times that of commercial Pt-C. Impedance spectroscopy shows different impedance behaviour at different potential regions, indicating change in methanol oxidation reaction mechanism with potential. The reversal of impedance pattern to the second quadrant, at potentials higher than ∼0.40 V, indicates change in the rate determining reaction.

  7. Morphology, thermal, mechanical, and barrier properties of graphene oxide/poly(lactic acid) nanocomposite films

    International Nuclear Information System (INIS)

    Kim, Seong Woo; Choi, Hyun Muk

    2016-01-01

    To improve the physical and gas barrier properties of biodegradable poly(lactic acid) (PLA) film, two graphene nanosheets of highly functionalized graphene oxide (0.3 wt% to 0.7 wt%) and low-functionalized graphene oxide (0.5 wt%) were incorporated into PLA resin via solution blending method. Subsequently, we investigated the effects of material parameters such as loading level and degree of functionalization for the graphene nanosheets on the morphology and properties of the resultant nanocomposites. The highly functionalized graphene oxide (GO) caused more exfoliation and homogeneous dispersion in PLA matrix as well as more sustainable suspensions in THF, compared to low-functionalized graphene oxide (LFGO). When loaded with GO from 0.3 wt% to 0.7 wt%, the glass transition temperature, degree of crystallinity, tensile strength and modulus increased steadily. The GO gave rise to more pronounced effect in the thermal and mechanical reinforcement, relative to LFGO. In addition, the preparation of fairly transparent PLA-based nanocomposite film with noticeably improved barrier performance achieved only when incorporated with GO up to 0.7wt%. As a result, GO may be more compatible with hydrophilic PLA resin, compared to LFGO, resulting in more prominent enhancement of nanocomposites properties.

  8. An experimental correlation approach for predicting thermal conductivity of water-EG based nanofluids of zinc oxide

    Science.gov (United States)

    Ahmadi Nadooshan, Afshin

    2017-03-01

    In this study, the effects of temperature (20 °Cthermal conductivity of zinc oxide/ethylene glycol-water nanofluid have been presented. Nanofluid samples were prepared by a two-step method and thermal conductivity measurements were performed by a KD2 pro instrument. Results showed that the thermal conductivity increases uniformly with increasing solid volume fraction and temperature. The results also revealed that the thermal conductivity of nanofluids significantly increases with increasing solid volume fraction at higher temperatures. Moreover, it can be seen that for more concentrated samples, the effect of temperature was more tangible. Experimental thermal conductivity enhancement of the nanofluid in comparison with the Maxwell model indicated that Maxwell model was unable to predict the thermal conductivity of the present nanofluid. Therefore, a new correlation was presented for predicting the thermal conductivity of ZnO/EG-water nanofluid.

  9. Low-temperature thermal reduction of graphene oxide: In situ correlative structural, thermal desorption, and electrical transport measurements

    Science.gov (United States)

    Lipatov, Alexey; Guinel, Maxime J.-F.; Muratov, Dmitry S.; Vanyushin, Vladislav O.; Wilson, Peter M.; Kolmakov, Andrei; Sinitskii, Alexander

    2018-01-01

    Elucidation of the structural transformations in graphene oxide (GO) upon reduction remains an active and important area of research. We report the results of in situ heating experiments, during which electrical, mass spectrometry, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and transmission electron microscopy (TEM) measurements were carried out correlatively. The simultaneous electrical and temperature programmed desorption measurements allowed us to correlate the onset of the increase in the electrical conductivity of GO by five orders of magnitude at about 150 °C with the maxima of the rates of desorption of H2O, CO, and CO2. Interestingly, this large conductivity change happens at an intermediate level of the reduction of GO, which likely corresponds to the point when the graphitic domains become large enough to enable percolative electronic transport. We demonstrate that the gas desorption is intimately related to (i) the changes in the chemical structure of GO detected by XPS and Raman spectroscopy and (ii) the formation of nanoscopic holes in GO sheets revealed by TEM. These in situ observations provide a better understanding of the mechanism of the GO thermal reduction.

  10. Enhancement of as-sputtered silver-tantalum oxide thin film coating on biomaterial stainless steel by surface thermal treatment

    Science.gov (United States)

    Alias, Rodianah; Mahmoodian, Reza; Shukor, Mohd Hamdi Abd; Yew, Been Seok; Muhamad, Martini

    2018-04-01

    Stainless steel 316L (SS316L) is extensively used as surgical/clinical tools due to its low carbon content and excellent mechanical characteristic. The fabrication of metal ceramic based on this metallic biomaterial favor its biofunctionality properties. However, instability phase of amorphous thin film lead to degradation, corrosion and oxidation. Thus, thin film coating requires elevated adhesion strength and higher surface hardness to meet clinical tools criteria. In this study, the SS316L was deposited with micron thickness of Ag-TaO thin film by using magnetron sputtering. The microstructure, elemental analysis and phase identification of Ag-TaO thin film were characterized by using FESEM, EDX and XRD, respectively; whereas the micro scratch test and micro hardness test were performed by using Micro Scratch Testing System and Vickers Micro Hardness Tester, respectively. It was found that the coating thin film's adhesion and hardness strength were improved from 672 to 2749 mN and 142 to 158 Hv respectively. It was found that the as-deposited surface were treated at 500 °C of temperatures with 2 °C/min ramping rate enhance 4.1 times of the adhesion strength value. Furthermore, FESEM characterization revealed coarsening structure of the thin film coating which can provide high durability service.

  11. An electrical method for the measurement of the thermal and electrical conductivity of reduced graphene oxide nanostructures.

    Science.gov (United States)

    Schwamb, Timo; Burg, Brian R; Schirmer, Niklas C; Poulikakos, Dimos

    2009-10-07

    This paper introduces an electrical four-point measurement method enabling thermal and electrical conductivity measurements of nanoscale materials. The method was applied to determine the thermal and electrical conductivity of reduced graphene oxide flakes. The dielectrophoretically deposited samples exhibited thermal conductivities in the range of 0.14-2.87 W m(-1) K(-1) and electrical conductivities in the range of 6.2 x 10(2)-6.2 x 10(3) Omega(-1) m(-1). The measured properties of each flake were found to be dependent on the duration of the thermal reduction and are in this sense controllable.

  12. Thermal Oxidation of a Carbon Condensate Formed in High-Frequency Carbon and Carbon-Nickel Plasma Flow

    Science.gov (United States)

    Churilov, G. N.; Nikolaev, N. S.; Cherepakhin, A. V.; Dudnik, A. I.; Tomashevich, E. V.; Trenikhin, M. V.; Bulina, N. G.

    2018-02-01

    We have reported on the comparative characteristics of thermal oxidation of a carbon condensate prepared by high-frequency arc evaporation of graphite rods and a rod with a hollow center filled with nickel powder. In the latter case, along with different forms of nanodisperse carbon, nickel particles with nickel core-carbon shell structures are formed. It has been found that the processes of the thermal oxidation of carbon condensates with and without nickel differ significantly. Nickel particles with the carbon shell exhibit catalytic properties with respect to the oxidation of nanosized carbon structures. A noticeable difference between the temperatures of the end of the oxidation process for various carbon nanoparticles and nickel particles with the carbon shell has been established. The study is aimed at investigations of the effect of nickel nanoparticles on the dynamics of carbon condensate oxidation upon heating in the argon-oxygen flow.

  13. A coupled mechanical-chemical model for reflecting the influence of stress on oxidation reactions in thermal barrier coating

    Science.gov (United States)

    Chen, Lin; Yueming, Li

    2018-06-01

    In this paper, a coupled mechanical-chemical model is established based on the thermodynamic framework, in which the contribution of chemical expansion to free energy is introduced. The stress-dependent chemical potential equilibrium at the gas-solid interface and the stress gradient-dependent diffusion equation as well as a so-called generalized force which is conjugate to the oxidation rate are derived from the proposed model, which could reflect the influence of stresses on the oxidation reaction. Based on the proposed coupled mechanical-chemical model, a user element subroutine is developed in ABAQUS. The numerical simulation of the high temperature oxidation in the thermal barrier coating is carried out to verify the accuracy of the proposed model, and then the influence of stresses on the oxidation reaction is investigated. In thermally grown oxide, the considerable stresses would be induced by permanent volumetric swelling during the oxidation. The stresses play an important role in the chemical potential equilibrium at the gas-solid interface and strongly affect the oxidation reaction. The gradient of the stresses, however, only occurs in the extremely thin oxidation front layer, which plays a very limited role in the oxidation reaction. The generalized force could be divided into the stress-dependent and the stress-independent parts. Comparing with the stress-independent part, the stress-dependent part is smaller, which has little influence on oxidation reaction.

  14. Global Kinetic Constants for Thermal Oxidative Degradation of a Cellulosic Paper

    Science.gov (United States)

    Kashiwagi, Takashi; Nambu, Hidesaburo

    1992-01-01

    Values of global kinetic constants for pyrolysis, thermal oxidative degradation, and char oxidation of a cellulosic paper were determined by a derivative thermal gravimetric study. The study was conducted at heating rates of 0.5, 1, 1.5, 3, and 5 C/min in ambient atmospheres of nitrogen, 0.28, 1.08, 5.2 percent oxygen concentrations, and air. Sample weight loss rate, concentrations of CO, CO2, and H2O in the degradation products, and oxygen consumption were continuously measured during the experiment. Values of activation energy, preexponential factor, orders of reaction, and yields of CO, CO2, H2O, total hydrocarbons, and char for each degradation reaction were derived from the results. Heat of reaction for each reaction was determined by differential scanning calorimetry. A comparison of the calculated CO, CO2, H2O, total hydrocarbons, sample weight loss rate, and oxygen consumption was made with the measured results using the derived kinetic constants, and the accuracy of the values of kinetic constants was discussed.

  15. Role of Oxides and Porosity on High-Temperature Oxidation of Liquid-Fueled HVOF Thermal-Sprayed Ni50Cr Coatings

    Science.gov (United States)

    Song, B.; Bai, M.; Voisey, K. T.; Hussain, T.

    2017-02-01

    High chromium content in Ni50Cr thermally sprayed coatings can generate a dense and protective scale at the surface of coating. Thus, the Ni50Cr coating is widely used in high-temperature oxidation and corrosion applications. A commercially available gas atomized Ni50Cr powder was sprayed onto a power plant steel (ASME P92) using a liquid-fueled high velocity oxy-fuel thermal spray with three processing parameters in this study. Microstructure of as-sprayed coatings was examined using oxygen content analysis, mercury intrusion porosimetry, scanning electron microscope (SEM), energy-dispersive x-ray spectroscopy (EDX) and x-ray diffraction (XRD). Short-term air oxidation tests (4 h) of freestanding coatings (without boiler steel substrate) in a thermogravimetric analyzer at 700 °C were performed to obtain the kinetics of oxidation of the as-sprayed coating. Long-term air oxidation tests (100 h) of the coated substrates were performed at same temperature to obtain the oxidation products for further characterization in detail using SEM/EDX and XRD. In all samples, oxides of various morphologies developed on top of the Ni50Cr coatings. Cr2O3 was the main oxidation product on the surface of all three coatings. The coating with medium porosity and medium oxygen content has the best high-temperature oxidation performance in this study.

  16. 16 CFR Figure 3 to Subpart A of... - Flooring Radiant Tester Schematic Side Elevation

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Flooring Radiant Tester Schematic Side Elevation 3 Figure 3 to Subpart A of Part 1209 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION.... 1209, Subpt. A, Fig. 3 Figure 3 to Subpart A of Part 1209—Flooring Radiant Tester Schematic Side...

  17. Hand-Drawn Resistors and a Simple Tester Using a Light-Emitting Diode

    Science.gov (United States)

    Kamata, Masahiro; Abe, Mayumi

    2012-01-01

    A thick line drawn on a sheet of paper with a 6B pencil is electrically conductive and its resistance can be roughly estimated using a simple tester made of a light-emitting diode (LED) and a lithium coin-type cell. Using this hand-drawn resistor and the LED tester, we developed teaching materials that help students to understand how electrical…

  18. High inter-tester reliability of the new mobility score in patients with hip fracture

    DEFF Research Database (Denmark)

    Kristensen, M.T.; Bandholm, T.; Foss, N.B.

    2008-01-01

    OBJECTIVE: To assess the inter-tester reliability of the New Mobility Score in patients with acute hip fracture. DESIGN: An inter-tester reliability study. SUBJECTS: Forty-eight consecutive patients with acute hip fracture at a median age of 84 (interquartile range, 76-89) years; 40 admitted from...

  19. Thermally evaporated mechanically hard tin oxide thin films for opto-electronic apllications

    Energy Technology Data Exchange (ETDEWEB)

    Tripathy, Sumanta K.; Rajeswari, V. P. [Centre for Nano Science and Technology, GVP College of Engineering (Autonomous), Visakhapatnam- 530048 (India)

    2014-01-28

    Tungsten doped tin oxide (WTO) and Molybdenum doped tin oxide (MoTO) thin film were deposited on corn glass by thermal evaporation method. The films were annealed at 350°C for one hour. Structural analysis using Xray diffraction data shows both the films are polycrystalline in nature with monoclinic structure of tin oxide, Sn{sub 3}O{sub 4}, corresponding to JCPDS card number 01-078-6064. SEM photograph showed that both the films have spherical grains with size in the range of 20–30 nm. Compositional analysis was carried out using EDS which reveals the presence of Sn, O and the dopant Mo/W only thereby indicating the absence of any secondary phase in the films. The films are found to contain nearly 6 wt% of Mo, 8 wt% of W as dopants respectively. The transmission pattern for both the films in the spectral range 200 – 2000 nm shows that W doping gives a transparency of nearly 80% from 380 nm onwards while Mo doping has less transparency of 39% at 380nm. Film hardness measurement using Triboscope shows a film hardness of about 9–10 GPa for both the films. It indicates that W or M doping in tin oxide provides the films the added advantage of withstanding the mechanical wear and tear due to environmental fluctuations By optimizing the optical and electrical properties, W/Mo doped tin oxide films may be explored as window layers in opto-electronic applications such as solar cells.

  20. Effect of Layer-Graded Bond Coats on Edge Stress Concentration and Oxidation Behavior of Thermal Barrier Coatings

    Science.gov (United States)

    Zhu, Dongming; Ghosn, Louis J.; Miller, Robert A.

    1998-01-01

    Thermal barrier coating (TBC) durability is closely related to design, processing and microstructure of the coating Z, tn systems. Two important issues that must be considered during the design of a thermal barrier coating are thermal expansion and modulus mismatch between the substrate and the ceramic layer, and substrate oxidation. In many cases, both of these issues may be best addressed through the selection of an appropriate bond coat system. In this study, a low thermal expansion and layer-graded bond coat system, that consists of plasma-sprayed FeCoNiCrAl and FeCrAlY coatings, and a high velocity oxyfuel (HVOF) sprayed FeCrAlY coating, is developed to minimize the thermal stresses and provide oxidation resistance. The thermal expansion and oxidation behavior of the coating system are also characterized, and the strain isolation effect of the bond coat system is analyzed using the finite element method (FEM). Experiments and finite element results show that the layer-graded bond coat system possesses lower interfacial stresses. better strain isolation and excellent oxidation resistance. thus significantly improving the coating performance and durability.

  1. Enhancing mechanical and thermal properties of styrene-butadiene rubber/carboxylated acrylonitrile butadiene rubber blend by the usage of graphene oxide with diverse oxidation degrees

    Science.gov (United States)

    Xue, Xiaodong; Yin, Qing; Jia, Hongbing; Zhang, Xuming; Wen, Yanwei; Ji, Qingmin; Xu, Zhaodong

    2017-11-01

    Graphene oxide (GO) with various oxidation degrees were prepared through a modified Hummer's method by varying the dosage of oxidizing agent. Styrene-butadiene rubber (SBR)/carboxylated acrylonitrile butadiene rubber (XNBR)/GO nanocomposites were fabricated by aqueous-phase mixing of GO colloidal dispersion with SBR latex and a small loading of XNBR latex, followed by co-coagulation. Effects of GO oxidation degree on the morphology, structure, mechanical and thermal properties of nanocomposites were thoroughly investigated. The results showed that the mechanical strength of nanocomposites were enhanced with the increase of oxidation degree of GO. Especially, when the weight ratio of KMnO4 to graphite was 15/5, the tensile strength, tear strength and thermal conductivity of SBR/XNBR/GO filled with 3 phr (parts per hundred rubber) GO increased by 255.3%, 141.5% and 22.8%, respectively, compared to those of neat SBR/XNBR blend. In addition, the thermal stability and the solvent resistance of the nanocomposites were also improved significantly. This work suggested that GO with higher oxidation degree could effectively improve the properties of SBR/XNBR blend.

  2. X-ray absorption spectroscopy study on the thermal and hydrazine reduction of graphene oxide

    International Nuclear Information System (INIS)

    Liang, Xianqing; Wang, Yu; Zheng, Huiyuan; Wu, Ziyu

    2014-01-01

    Highlights: • XAS study of GO and reduced GO was performed. • Detailed evolution of the electronic structures and chemical bonding of GO was revealed. • A new efficient route for the reduction of GO is proposed. - Abstract: X-ray absorption spectroscopy (XAS) was applied to systemically investigate the deoxygenation of graphene oxide (GO) via annealing and hydrazine treatment. Detailed evolution of the electronic structures and chemical bonding of GO was presented. The enhanced intensity of π * resonance and the appearance of splitting σ * resonance in C K-edge XAS spectra suggest high extents of recoveries of π-conjugation upon reduction using thermal annealing or hydrazine. Experimental results revealed that the carboxyl as well as epoxide and hydroxyl groups on the surface of GO were thermally reduced first, followed by the more difficult removal of carbonyl and cyclic ether groups at higher temperatures. The hydrazine reduction could remove epoxide, hydroxyl and carboxyl groups effectively, whereas the carbonyl groups were partially reduced with the incorporation of nitrogen species simultaneously. The residual oxygen functional groups on hydrazine-reduced GO could be further removed after modest thermal annealing. It was proposed that a combination of both types of reductions would give the best deoxygenation efficiency for the production of graphene

  3. Enhanced thermal properties with graphene oxide in the urea-formaldehyde microcapsules containing paraffin PCMs.

    Science.gov (United States)

    Qiao, Zhen; Mao, Jian

    2017-02-01

    In this study, compact urea-formaldehyde microcapsules containing paraffin (UFP) phase change materials (PCMs) were prepared via in situ polymerisation. The thermal conductivity of the PCMs was enhanced without influencing their enthalpy by adding graphene oxide (GO). Two modification methods were investigated: One in which GO is added to the inside of microcapsules, defined as "paraffin/GO@UF composite"; and another in which GO is coated onto the surface of shell, defined as "paraffin@UF/GO composite". The GO sheets were visible in scanning electron microscope (SEM) images of paraffin@UF/GO composite. The thermal conductivity was 0.2236 ± 0.0003 W/(m·K) for UFP particles, was 0.2517 ± 0.0003 W/(m·K) for the paraffin/GO@UF composite (10 wt%), and was 1.0670 ± 0.0020 W/(m·K) for paraffin@UF/GO composite (10 wt%), respectively. The encapsulation efficiency of all samples exceeded 80% (w/w) and all samples exhibited favourable thermal stability and reliability. The IR emissivity of paraffin@UF/GO was lower than that of paraffin/GO@UF when the same GO amount was added to the composite.

  4. Thermal stability of pulsed laser deposited iridium oxide thin films at low oxygen atmosphere

    Science.gov (United States)

    Gong, Yansheng; Wang, Chuanbin; Shen, Qiang; Zhang, Lianmeng

    2013-11-01

    Iridium oxide (IrO2) thin films have been regarded as a leading candidate for bottom electrode and diffusion barrier of ferroelectric capacitors, some process related issues need to be considered before integrating ferroelectric capacitors into memory cells. This paper presents the thermal stability of pulsed laser deposited IrO2 thin films at low oxygen atmosphere. Emphasis was given on the effect of post-deposition annealing temperature at different oxygen pressure (PO2) on the crystal structure, surface morphology, electrical resistivity, carrier concentration and mobility of IrO2 thin films. The results showed that the thermal stability of IrO2 thin films was strongly dependent on the oxygen pressure and annealing temperature. IrO2 thin films can stably exist below 923 K at PO2 = 1 Pa, which had a higher stability than the previous reported results. The surface morphology of IrO2 thin films depended on PO2 and annealing temperature, showing a flat and uniform surface for the annealed films. Electrical properties were found to be sensitive to both the annealing temperature and oxygen pressure. The room-temperature resistivity of IrO2 thin films with a value of 49-58 μΩ cm increased with annealing temperature at PO2 = 1 Pa. The thermal stability of IrO2 thin films as a function of oxygen pressure and annealing temperature was almost consistent with thermodynamic calculation.

  5. Magnetic properties of thermally reduced graphene oxide decorated with PtNi nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Huízar-Félix, A.M. [Universidad Autónoma de Nuevo León, UANL, Facultad de Ingeniería Mecánica y Eléctrica, FIME, Ave. Pedro de Alba s/n, Ciudad Universitaria, C.P.66455 San Nicolás de los Garza, N.L. (Mexico); Departamento de Electricidad y Electrónica, Universidad del País Vasco (UPV/EHU), 48940 Leioa (Spain); BC Materials, Basque Centre for Materials, Applications and Nanostructures, 48160 Derio (Spain); Cruz-Silva, R. [Research Center for Exotic NanoCarbon, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553 (Japan); Barandiarán, J.M. [Departamento de Electricidad y Electrónica, Universidad del País Vasco (UPV/EHU), 48940 Leioa (Spain); BC Materials, Basque Centre for Materials, Applications and Nanostructures, 48160 Derio (Spain); García-Gutiérrez, D.I. [Universidad Autónoma de Nuevo León, UANL, Facultad de Ingeniería Mecánica y Eléctrica, FIME, Ave. Pedro de Alba s/n, Ciudad Universitaria, C.P.66455 San Nicolás de los Garza, N.L. (Mexico); Orue, I. [SGIKER Medidas Magnéticas, Facultad de Ciencia y Tecnología, Universidad del País Vasco (UPV/EHU), 48940 Leioa (Spain); and others

    2016-09-05

    Nanocomposites of reduced graphene oxide (RGO) with PtNi nanoparticles were obtained by in situ thermal reduction of a physical mixture of GO and metallic precursors. RGO and PtNiRGO nanocomposites were studied by differential thermal analysis and thermogravimetry, Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (XRD), as well as scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The method presented here is a one-step thermal reduction procedure that allows the deposition of bimetallic PtNi nanoparticles with tetragonal crystalline structure and particle size ranging from 3 nm to 30 nm on RGO. The magnetic properties of the RGO and PtNiRGO nanocomposites were measured by vibrating sample magnetometry, which revealed that the RGO exhibited diamagnetism at room temperature and paramagnetism at temperatures below 10 K. PtNiRGO nanocomposites show hysteresis and ferromagnetic ordering at room temperature with a Curie temperature of 658 K. In addition, its magnetic properties at low temperature were strongly influenced by the paramagnetic contribution of RGO and the morphology of the bimetallic nanoparticles. - Highlights: • Simultaneous synthesis method for growth of PtNi nanoparticles on RGO. • Microstructural features of PtNiRGO nanocomposite were studied with extensive characterization. • Diamagnetic behavior of RGO and ferromagnetic ordering for PtNiRGO nanocomposite.

  6. Effects of thermal treatment on the anodic growth of tungsten oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Chai, Y., E-mail: yqchai85@gmail.com; Tam, C.W.; Beh, K.P.; Yam, F.K.; Hassan, Z.

    2015-08-03

    This work reports the investigation of the effects of thermal treatment on anodic growth tungsten oxide (WO{sub 3}). The increase of the thermal treatment temperature above 400 °C significantly influences WO{sub 3} film where high porosity structure reduces to more compact film. As-grown film is amorphous, which transforms to monoclinic/orthorhombic phase upon annealing at 300–600 °C. With the reducing of porous structure, preferential growth of (002) plane shifts to (020) plane at 600 °C with more than twentyfold increase of peak's intensity compared to the film annealed at 500 °C. Films annealed at low thermal treatment show better ion intercalation and reversibility during electrochemical measurements; however, it has larger optical band gap. Photoelectrochemical measurement reveals that film annealed at 400 °C exhibits the best photocatalytic performance among the films annealed at 300–600 °C. - Highlights: • Porosity of the WO{sub 3} reduces as annealing temperature increases above 400 °C. • As-grown film is amorphous which transforms to monoclinic/orthorhombic upon annealing. • As-grown film shows better ion intercalation in electrochemical process. • Optical band gap of WO{sub 3} reduces as the annealing temperature increases. • Film annealed at 400 °C exhibits best photocatalytic performance.

  7. Thermally insulating and fire-retardant lightweight anisotropic foams based on nanocellulose and graphene oxide

    Science.gov (United States)

    Wicklein, Bernd; Kocjan, Andraž; Salazar-Alvarez, German; Carosio, Federico; Camino, Giovanni; Antonietti, Markus; Bergström, Lennart

    2015-03-01

    High-performance thermally insulating materials from renewable resources are needed to improve the energy efficiency of buildings. Traditional fossil-fuel-derived insulation materials such as expanded polystyrene and polyurethane have thermal conductivities that are too high for retrofitting or for building new, surface-efficient passive houses. Tailored materials such as aerogels and vacuum insulating panels are fragile and susceptible to perforation. Here, we show that freeze-casting suspensions of cellulose nanofibres, graphene oxide and sepiolite nanorods produces super-insulating, fire-retardant and strong anisotropic foams that perform better than traditional polymer-based insulating materials. The foams are ultralight, show excellent combustion resistance and exhibit a thermal conductivity of 15 mW m-1 K-1, which is about half that of expanded polystyrene. At 30 °C and 85% relative humidity, the foams retained more than half of their initial strength. Our results show that nanoscale engineering is a promising strategy for producing foams with excellent properties using cellulose and other renewable nanosized fibrous materials.

  8. Evaluation of dampers using a resonance adhesion tester

    Directory of Open Access Journals (Sweden)

    Stanislav Koláček

    2013-01-01

    Full Text Available This paper describes the diagnostics of dampers using resonant adhesion tester. This kind of test is non-invasive and evaluation is based on the EUSAMA methodology. The main goals of this method were to practically measure and evaluate technical condition of the shock absorbers. However, this method does not measure only damper properties, but the whole axle, too. During measurements, one must take into account the fact that the results can be easily influenced by external factors. These include e.g. wrong tire pressure, different kind of shock absorbers, and tires. The actual testing revealed that the measurement results are also influenced by bad condition of the vehicle axles. If we eliminate all these draw-backs, dampers testing can be very accurate.

  9. Trial of prestressed concrete cable testing by sonic integrity tester

    International Nuclear Information System (INIS)

    Sugimoto, Masanobu

    1997-01-01

    Highway road network of Japan is in good condition. Those roads were constructed as social infrastructures. But some damages were occurred and propagated in concrete structure which passed more than 20 years after construction. As for the damages load caring capacity of bridge was decreased due to fatigue of increasing traffics and bridge vibration. Recently many troubles happened in PC structure as cut off of the main cables by corrosion and flying the non-grouting PC-bar to roadside. Some case can be checked by hammering testing method and X-ray photo cut or not and condition of cement grouting. But another case has not checking method. Now we are testing for the PC cables by sonic integrity tester which is modified from FPDS(Foundation Pile Diagnosis System). We report in this paper on this result and scope of the future of this method.

  10. Microprocessor tester for the treat upgrade reactor trip system

    International Nuclear Information System (INIS)

    Lenkszus, F.R.; Bucher, R.G.

    1984-01-01

    The upgrading of the Transient Reactor Test (TREAT) Facility at ANL-Idaho has been designed to provide additional experimental capabilities for the study of core disruptive accident (CDA) phenomena. In addition, a programmable Automated Reactor Control System (ARCS) will permit high-power transients up to 11,000 MW having a controlled reactor period of from 15 to 0.1 sec. These modifications to the core neutronics will improve simulation of LMFBR accident conditions. Finally, a sophisticated, multiply-redundant safety system, the Reactor Trip System (RTS), will provide safe operation for both steady state and transient production operating modes. To insure that this complex safety system is functioning properly, a Dedicated Microprocessor Tester (DMT) has been implemented to perform a thorough checkout of the RTS prior to all TREAT operations

  11. A portable fracture toughness tester for biological materials

    Science.gov (United States)

    Darvell, B. W.; Lee, P. K. D.; Yuen, T. D. B.; Lucas, P. W.

    1996-06-01

    A portable mechanical tester is described which is both lightweight and cheap to produce. The machine is simple and convenient to operate and requires only a minimum of personnel training. It can be used to measure the fundamental mechanical properties of pliant solids, particularly toughness (in the sense of `work of fracture') using either scissors or wedge tests. This is achieved through a novel hardware integration technique. The circuits are described. The use of the machine does not require a chart recorder but it can be linked to a personal computer, either to show force - displacement relationships or for data storage. The design allows the use of any relatively `soft' mechanical test, i.e. tests in which the deformability of the frame of the machine and its load cell do not introduce significant errors into the results. Examples of its use in measuring the toughness of biomaterials by scissors (paper, wood) and wedges (mung bean starch gels) are given.

  12. The development and application of portable speed tester for special equipment

    International Nuclear Information System (INIS)

    Lan Peng; Chen Ligang; Dai Sidan; Wang Huiting; Zhang Liangxu; Wang Lin

    2014-01-01

    Special equipment developed to meet the needs for research and industrial application of this stage, with the advantages of small size, high accuracy, long working hours, high reliability and intelligent portable speed tester. This paper describes the development and application of the tester. In terms of hardware, the tester use 'MCU + CPLD' to build the core of the system, and focus on high precision, low-power design, Software to increase their power electricity monitoring and filtering software anti-interference function. The tester can achieve high-precision measurement of the speed parameter, display measurement data in real time via the LCD display functions. Currently, the tester has been successfully achieved industrial application. (authors)

  13. Design, Construction, and Evaluation of Rubber Friction Tester

    Directory of Open Access Journals (Sweden)

    Mehdi Razzaghi Kashani

    2012-12-01

    Full Text Available Coeffcient of  friction  (COF  for  rubber parts  is one of  the key parameters in their interaction with solid rough surfaces (micrometer to millimeter scales,  such  as  tire-road  interactions. COF  of  rubber  depends  on  viscoelastic properties of rubber, roughness characteristics of the counter-part surface, and process variables such as contact nominal pressure and sliding speed. Due to the need for measuring COF  for  rubber,  a  new  friction  tester, with  continuous  variation  of nominal pressure and sliding speed, was designed and constructed in order to assess the effect of above mentioned parameters. Tire tread compounds, as the most common rubber part  in  the feld of  rubber  tribology, was used  for  this purpose. Viscoelastic properties of compounds were varied by changing composition of styrene-butadiene rubber (SBR and butadiene rubber (BR in the blend. Effect of surface roughness was evaluated by using silicon-carbide papers with different roughness parameters. By statistical analysis it was shown that the designed friction tester has high accuracy in measuring the coeffcient of friction of rubber and differentiating the effective parameters. Increasing the nominal pressure led to reduction of COF and increase in sliding speed forced it through a maximum. In conclusion, the loss factor of the compound and asymmetry in roughness distribution of the counter-surface are considered as the most effective parameters on COF of rubber.

  14. Initial Development of an Electronic Testis Rigidity Tester

    Directory of Open Access Journals (Sweden)

    Petros Mirilas

    2011-01-01

    Full Text Available We aimed to develop our previously presented mechanical device, the Testis Rigidity Tester (TRT, into an electronic system (Electronic Testis Rigidity Tester, ETRT by applying tactile imaging, which has been used successfully with other solid organs. A measuring device, located at the front end of the ETRT incorporates a tactile sensor comprising an array of microsensors. By application of a predetermined deformation of 2 mm, increased pressure alters linearly the resistance of each microsensor, producing changes of voltage. These signals were amplified, filtered, and digitized, and then processed by an electronic collector system, which presented them as a color-filled contour plot of the area of the testis coming into contact with the sensor. Testis models of different rigidity served for initial evaluation of ETRT; their evacuated central spaces contained different, increasing glue masses. An independent method of rigidity measurement, using an electric weight scale and a micrometer, showed that the more the glue injected, the greater the force needed for a 2-mm deformation. In a preliminary test, a single sensor connected to a multimeter showed similar force measurement for the same deformation in these phantoms. For each of the testis models compressed in the same manner, the ETRT system offered a map of pressures, represented by a color scale within the contour plot of the contact area with the sensor. ETRT found certain differences in rigidity between models that had escaped detection by a blind observer. ETRT is easy to use and provides a color-coded “insight“ of the testis internal structure. After experimental testing, it could be valuable in intraoperative evaluation of testes, so that the surgeon can decide about orchectomy or orcheopexy.

  15. Enhanced mechanical properties of chitosan/nanodiamond composites by improving interphase using thermal oxidation of nanodiamond.

    Science.gov (United States)

    Delavar, Zahra; Shojaei, Akbar

    2017-07-01

    Polymer composite films based on chitosan (CS) and nanodimaond (ND) were prepared using solution casting method. ND with variable contents of carboxylic functional group was prepared using thermal oxidation at temperature of 420°C under air atmosphere at various durations of 1.5 and 4.5h. The interfacial interaction between NDs and CS and morphological evolution of CS in presence of NDs were investigated by Fourier transform infrared (FTIR), differential scanning calorimeter (DSC) and X-ray diffraction (XRD) analyses. A significant improvement in tensile strength (∼85%) and tensile modulus (∼125%) of CS was achieved by oxidized ND (OND) obtained at higher oxidation time of 4.5 at low concentrations (below 1.5wt%). Theoretical analyses based on micromechanical models showed that the ND with higher degree of carboxylic functionality provided thicker and stronger interphase region which was reflected in higher mechanical properties. The equilibrium water uptake of CS decreased by incorporating ND and increasing its degree of carboxyl functionality. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Studies on the optoelectronic properties of the thermally evaporated tin-doped indium oxide nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Ko-Ying [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300, Taiwan, ROC (China); Lin, Liang-Da [Institute of Materials Science and Nanotechnology, Chinese Culture University, Taipei 111, Taiwan, ROC (China); Chang, Li-Wei [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300, Taiwan, ROC (China); Shih, Han C., E-mail: hcshih@mx.nthu.edu.tw [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300, Taiwan, ROC (China); Institute of Materials Science and Nanotechnology, Chinese Culture University, Taipei 111, Taiwan, ROC (China)

    2013-05-15

    Indium oxide (In{sub 2}O{sub 3}) nanorods, nanotowers and tin-doped (Sn:In = 1:100) indium oxide (ITO) nanorods have been fabricated by thermal evaporation. The morphology, microstructure and chemical composition of these three nanoproducts are characterized by FE-SEM, HRTEM and XPS. To further investigate the optoelectronic properties, the I–V curves and cathodoluminescence (CL) spectra are measured. The electrical resistivity of In{sub 2}O{sub 3} nanorods, nanotowers and ITO nanorods are 1.32 kΩ, 0.65 kΩ and 0.063 kΩ, respectively. CL spectra of these three nanoproducts clearly indicate that tin-doped (Sn:In = 1:100) indium oxide (ITO) nanorods cause a blue shift. No doubt ITO nanorods obtain the highest performance among these three nanoproducts, and this also means that Sn-doped In{sub 2}O{sub 3} nanostructures would be the best way to enhance the optoelectronic properties. Additionally, the growing mechanism and the optoelectronic properties of these three nanostructures are discussed. This study is beneficial to the applications of In{sub 2}O{sub 3} nanorods, nanotowers and ITO nanorods in optoelectronic nanodevices.

  17. Kinetics of irreversible thermal decomposition of dissociating nitrogen dioxide with nitrogen oxide or oxygen additions

    International Nuclear Information System (INIS)

    Gvozdev, A.A.

    1987-01-01

    The effect of NO or O 2 admixtures on kinetics of the irreversible thermal decomposition of nitrogen dioxide at temperatures 460-520 deg C and pressures 4-7 MPa has been studied. It follows from experimental data that the rate of N 2 O 4 formation reduces with the increase of partial pressure of oxygen or decrease of partial pressure of nitrogen oxide. The same regularity is seen for the rate of nitrogen formation. The rate constants of N 2 O formation in dissociating nitrogen tetroxide with oxygen or nitrogen oxide additions agree satisfactorily with previously published results, obtained in stoichiometric mixtures. The appreciable discrepancy at 520 deg C is bind with considerable degree of nitrogen oxide transformation which constitutes approximately 14%. It is determined that the kinetics of formation of the products of irreversible N 2 O and N 2 decomposition in stoichiometric and non-stoichiometric 2NO 2 ↔ 2NO+O 2 mixtures is described by identical 3NO → N 2 O+NO 2 and N 2 O+NO → N 2 +NO 2 reactions

  18. Improved oxidation of air pollutants in a non-thermal plasma

    International Nuclear Information System (INIS)

    Roland, U.; Holzer, F.; Kopinke, F.-D.

    2002-01-01

    The performance of non-thermal plasma (NTP) for the removal of organic air pollutants (especially in low concentrations) is improved by the introduction of ferroelectric and catalytically active materials into the discharge zone of an NTP reactor. Experiments with model systems (various contaminants and packed-bed materials) have shown that such a modification of a homogeneous gas-phase plasma can overcome the most serious restrictions of the NTP technique at its present state of the art: the incomplete total oxidation (i.e. the low selectivity to CO 2 ) and the energetic inefficiency. Placing a ferroelectric packed-bed material in the discharge zone was shown to result in a lowering of the energy input required. The main effects of plasma catalysis enabled by the introduction of a catalytically active material were an enhanced conversion of pollutants and a higher CO 2 selectivity. These improvements are based on the presence of short-lived oxidising species in the inner volume of porous catalysts. Additionally, the formation of a reservoir of adsorbed oxidants in the NTP zone could be shown. The combination of both modifications (ferroelectric packed-bed materials and plasma catalysis) is a promising method to support the NTP-initiated oxidation of air pollutants

  19. Bright electroluminescence from a chelate phosphine oxide Eu{sup III} complex with high thermal performance

    Energy Technology Data Exchange (ETDEWEB)

    Xu Hui [School of Chemistry and Materials, Heilongjiang University, 74 Xuefu Road, Nangang District, Harbin 150080, Heilongjiang Province (China); Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications, 66 Xinmofan Road, Nanjing 21003, Jiangsu Province (China); Yin Kun; Wang Lianhui [Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications, 66 Xinmofan Road, Nanjing 21003, Jiangsu Province (China); Huang Wei [Institute of Advanced Materials (IAM), Fudan University, 220 Handan Road, Shanghai 200433 (China)], E-mail: wei-huang@njupt.edu.cn

    2008-10-01

    The chelate phosphine oxide ligand 1,8-bis(diphenylphosphino)naphthalene oxide (NaPO) was used to prepare complex 1 tris(2-thenoyltrifluoroacetonate)(1,8-bis(diphenylphosphino)naphthalene oxide)europium(III). The rigid structure of NaPO makes 1 have more compact structure resulting in a temperature of glass transition as high as 147 deg. C, which is the highest in luminescent Eu{sup III} complexes, and a higher decomposition temperature of 349 deg. C. The improvement of carrier transfer ability of NaPO was proved by Gaussian simulation. The multi-layered electroluminescent device based on 1 had a low turn-on voltage of 6.0 V, the maximum brightness of 601 cd m{sup -2} at 21.5 V and 481.4 mA cm{sup -2}, and the excellent voltage-independent spectral stability. These properties demonstrated NaPO cannot only be favorable to form the rigid and compact complex structure, and increase the thermal and morphological stability of the complex, but also reduce the formation of the exciplex.

  20. A facile strategy for the reduction of graphene oxide and its effect on thermal conductivity of epoxy based composites

    Directory of Open Access Journals (Sweden)

    F. Xie

    2016-06-01

    Full Text Available A facile and efficient approach to reduce graphene oxide with Al particles and potassium hydroxide was developed at moderate temperature and the graphene/epoxy composite was prepared by mould casting method. The as-prepared graphene has been confirmed by Transmission electron microscopy, Fourier transform infrared spectrometer, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Thermal gravimetric analysis. This provides a new green way to synthesize graphene with high surface area and opens another opportunity for the production of graphene. Effects of graphene on thermal conductivity, thermal stability and microstructures of the epoxy-based composite were also investigated. The results showed that thermal conductivity of the composite exhibited a remarkable improvement with increasing content of graphene and thermal conductivity could reach 1.192 W/(m*K when filled with 3 wt% graphene. Moreover, graphene/epoxy composite exhibits good thermal stability with 3 wt% graphene.

  1. GAPCON-THERMAL-2: a computer program for calculating the thermal behavior of an oxide fuel rod

    International Nuclear Information System (INIS)

    Beyer, C.E.; Hann, C.R.; Lanning, D.D.; Panisko, F.E.; Parchen, L.J.

    1975-11-01

    A description is presented of the computer code GAPCON THERMAL-2, a light water reactor (LWR) fuel thermal performance prediction code. GAPCON-THERMAL-2, is intended to be used as a calculational tool for reactor fuel steady-state thermal performance and to provide input for accident analyses. Some models used in the code provide best estimate as well as conservative predictions. Each of the individual models in the code is based on the best available data

  2. A novel thermal decomposition approach for the synthesis of silica-iron oxide core–shell nanoparticles

    International Nuclear Information System (INIS)

    Kishore, P.N.R.; Jeevanandam, P.

    2012-01-01

    Highlights: ► Silica-iron oxide core–shell nanoparticles have been synthesized by a novel thermal decomposition approach. ► The silica-iron oxide core–shell nanoparticles are superparamagnetic at room temperature. ► The silica-iron oxide core–shell nanoparticles serve as good photocatalyst for the degradation of Rhodamine B. - Abstract: A simple thermal decomposition approach for the synthesis of magnetic nanoparticles consisting of silica as core and iron oxide nanoparticles as shell has been reported. The iron oxide nanoparticles were deposited on the silica spheres (mean diameter = 244 ± 13 nm) by the thermal decomposition of iron (III) acetylacetonate, in diphenyl ether, in the presence of SiO 2 . The core–shell nanoparticles were characterized by X-ray diffraction, infrared spectroscopy, field emission-scanning electron microscopy coupled with energy dispersive X-ray analysis, transmission electron microscopy, diffuse reflectance spectroscopy, and magnetic measurements. The results confirm the presence of iron oxide nanoparticles on the silica core. The core–shell nanoparticles are superparamagnetic at room temperature indicating the presence of iron oxide nanoparticles on silica. The core–shell nanoparticles have been demonstrated as good photocatalyst for the degradation of Rhodamine B.

  3. Thermal oxidation of cesium loaded Prussian blue as a precaution for exothermic phase change in extreme conditions

    International Nuclear Information System (INIS)

    Parajuli, Durga; Tanaka, Hisashi; Takahashi, Akira; Kawamoto, Tohru

    2013-01-01

    Cesium adsorbed Prussian blue is studied for the thermal oxidation. The TG-DTA shows exothermic phase change of micro aggregates of nano-PB at above 270°C. For this reason, Cs loaded PB was heated between 180 to 260°C. Heating at 180 removed only the water. Neither the oxidation of Iron nor the removal of cyanide is observed at this temperature. Oxidation of cyanide is observed upon heating above 200°C while loaded Cs is released after heating at >250°C followed by washing with water. Thermal oxidation between 200 to 220°C for more than 2 h showed control on exothermic phase change and loaded Cs is also not solubilized. (author)

  4. Mixed oxide thermal behaviour at BOL: COMETHE III-J models and impact on power-to-melt

    International Nuclear Information System (INIS)

    Vliet, J. van

    1979-01-01

    The mixed oxide thermal behaviour at beginning of life is very important because it can impose a limitation to the fuel pin peak power, and therefore to the reactor thermal output. The relevant physical processes leading to fuel restructuring are modelled in COMETHE III-J in a kinetic way. This ensures that the temperature and power history are properly taken into account. These models are described and their impact on the calculated power to melt early in life is analysed. (author)

  5. Analysis of thermal treatment effects upon optico-luminescent and scintillation characteristics of oxide and chalcogenide crystals

    International Nuclear Information System (INIS)

    Ryzhikov, Vladimir D.; Grinyov, Boris V.; Pirogov, Evgeniy N.; Galkin, Sergey N.; Nagornaya, Lyudmila L.; Bondar, Vladimir G.; Babiychuk, Inna P.; Krivoshein, Vadim I.; Silin, Vitaliy I.; Lalayants, Alexandr I.; Voronkin, Evgeniy F.; Katrunov, Konstantin A.; Onishchenko, Gennadiy M.; Vostretsov, Yuriy Ya.; Malyi, Pavel Yu.; Lisetskaya, Elena K.; Lisetskii, Longin N.

    2005-01-01

    This work has been aimed at analyzing the effects of various thermal treatment factors upon optical-luminescent, scintillation and other functional characteristics of complex oxide and chalcogenide crystals. The crystals considered in this work are scintillators with intrinsic (PWO, CWO, BGO), activator (GSO:Ce) or complex-defect ZnSe(Te) type of luminescence. Important factors of thermal treatment are not only the temperature and its variation with time, but also the chemical composition of the annealing medium, its oxidation-reduction properties

  6. Tuning the Electrical and Thermal Conductivities of Thermoelectric Oxides through Impurity Doping

    Science.gov (United States)

    Torres Arango, Maria A.

    Waste heat and thermal gradients available at power plants can be harvested to power wireless networks and sensors by using thermoelectric (TE) generators that directly transform temperature differentials into electrical power. Oxide materials are promising for TE applications in harsh industrial environments for waste heat recovery at high temperatures in air, because they are lightweight, cheaply produced, highly efficient, and stable at high temperatures in air. Ca3Co4O9(CCO) with layered structure is a promising p-type thermoelectric oxide with extrapolated ZT value of 0.87 in single crystal form [1]. However the ZT values for the polycrystalline ceramics remain low of ˜0.1-0.3. In this research, nanostructure engineering approaches including doping and addition of nanoinclusions were applied to the polycrystalline CCO ceramic to improve the energy conversion efficiency. Polycrystalline CCO samples with various Bi doping levels were prepared through the sol-gel chemical route synthesis of powders, pressing and sintering of the pellets. Microstructure features of Bi doped ceramic bulk samples such as porosity, development of crystal texture, grain boundary dislocations and segregation of Bi dopants at various grain boundaries are investigated from microns to atomic scale. The results of the present study show that the Bi-doping is affecting both the electrical conductivity and thermal conductivity simultaneously, and the optimum Bi doping level is strongly correlated with the microstructure and the processing conditions of the ceramic samples. At the optimum doping level and processing conditions of the ceramic samples, the Bi substitution of Ca results in the increase of the electrical conductivity, decrease of the thermal conductivity, and improvement of the crystal texture. The atomic resolution Scanning Transmission Electron Microscopy (STEM) Z-contrast imaging and the chemistry analysis also reveal the Bi-segregation at grain boundaries of CCO

  7. Effect of block composition on thermal properties and melt viscosity of poly[2-(dimethylaminoethyl methacrylate], poly(ethylene oxide and poly(propylene oxide block co-polymers

    Directory of Open Access Journals (Sweden)

    2011-09-01

    Full Text Available To modify the rheological properties of certain commercial polymers, a set of block copolymers were synthesized through oxyanionic polymerization of 2-(dimethylaminoethyl methacrylate to the chain ends of commercial prepolymers, namely poly(ethylene oxide (PEO, poly(ethylene oxide-block-poly(propylene oxide-block-poly(ethylene oxide (PEO-PPO-PEO, and poly(propylene oxide (PPO. The formed block copolymers were analysed with size exclusion chromatography and nuclear magnetic resonance spectroscopy in order to confirm block formation. Thermal characterization of the resulting polymers was done with differential scanning calorimetry. Thermal transition points were also confirmed with rotational rheometry, which was primarily used to measure melt strength properties of the resulting block co-polymers. It was observed that the synthesised poly[2-(dimethylaminoethyl methacrylate]-block (PDM affected slightly the thermal transition points of crystalline PEO-block but the influence was stronger on amorphous PPO-blocks. Frequency sweeps measured above the melting temperatures for the materials confirmed that the pre-polymers (PEO and PEO-PPO-PEO behave as Newtonian fluids whereas polymers with a PDM block structure exhibit clear shear thinning behaviour. In addition, the PDM block increased the melt viscosity when compared with that one of the pre-polymer. As a final result, it became obvious that pre-polymers modified with PDM were in entangled form, in the melted state as well in the solidified form.

  8. Growth of thermal oxide layers on GaAs and InP in the presence of ammonium heptamolybdate

    International Nuclear Information System (INIS)

    Mittova, I.Ya.; Lavrushina, S.S.; Afonchikova, A.V.

    2004-01-01

    Processes of thermal oxidation of GaAs and InP in the presence of ammonium heptamolybdate were studied using the methods of X-ray fluorescence analysis and IR spectroscopy at temperatures 480-580 Deg C. It was ascertained that introduction of the activator into the system results in accelerated growth of layers on semiconductors due to participation of anionic component of the chemostimulator in oxidation processes. The activator is integrated into the salts formed [ru

  9. A thermally robust and thickness independent ferroelectric phase in laminated hafnium zirconium oxide

    Directory of Open Access Journals (Sweden)

    S. Riedel

    2016-09-01

    Full Text Available Ferroelectric properties in hafnium oxide based thin films have recovered the scaling potential for ferroelectric memories due to their ultra-thin-film- and CMOS-compatibility. However, the variety of physical phenomena connected to ferroelectricity allows a wider range of applications for these materials than ferroelectric memory. Especially mixed HfxZr1-xO2 thin films exhibit a broad compositional range of ferroelectric phase stability and provide the possibility to tailor material properties for multiple applications. Here it is shown that the limited thermal stability and thick-film capability of HfxZr1-xO2 can be overcome by a laminated approach using alumina interlayers.

  10. Nitrated graphene oxide and its catalytic activity in thermal decomposition of ammonium perchlorate

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wenwen; Luo, Qingping; Duan, Xiaohui [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); Zhou, Yong [Eco-materials and Renewable Energy Research Center (ERERC), School of Physics, National Lab of Solid State Microstructure, ERERC, Nanjing University, Nanjing 210093 (China); Pei, Chonghua, E-mail: peichonghua@swust.edu.cn [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China)

    2014-02-01

    Highlights: • The NGO was synthesized by nitrifying homemade GO. • The N content of resulted NGO is up to 1.45 wt.%. • The NGO can facilitate the decomposition of AP and release much heat. - Abstract: Nitrated graphene oxide (NGO) was synthesized by nitrifying homemade GO with nitro-sulfuric acid. Fourier transform infrared spectroscopy (FTIR), laser Raman spectroscopy, CP/MAS {sup 13}C NMR spectra and X-ray photoelectron spectroscopy (XPS) were used to characterize the structure of NGO. The thickness and the compositions of GO and NGO were analyzed by atomic force microscopy (AFM) and elemental analysis (EA), respectively. The catalytic effect of the NGO for the thermal decomposition of ammonium perchlorate (AP) was investigated by differential scanning calorimetry (DSC). Adding 10% of NGO to AP decreases the decomposition temperature by 106 °C and increases the apparent decomposition heat from 875 to 3236 J/g.

  11. Nitrated graphene oxide and its catalytic activity in thermal decomposition of ammonium perchlorate

    International Nuclear Information System (INIS)

    Zhang, Wenwen; Luo, Qingping; Duan, Xiaohui; Zhou, Yong; Pei, Chonghua

    2014-01-01

    Highlights: • The NGO was synthesized by nitrifying homemade GO. • The N content of resulted NGO is up to 1.45 wt.%. • The NGO can facilitate the decomposition of AP and release much heat. - Abstract: Nitrated graphene oxide (NGO) was synthesized by nitrifying homemade GO with nitro-sulfuric acid. Fourier transform infrared spectroscopy (FTIR), laser Raman spectroscopy, CP/MAS 13 C NMR spectra and X-ray photoelectron spectroscopy (XPS) were used to characterize the structure of NGO. The thickness and the compositions of GO and NGO were analyzed by atomic force microscopy (AFM) and elemental analysis (EA), respectively. The catalytic effect of the NGO for the thermal decomposition of ammonium perchlorate (AP) was investigated by differential scanning calorimetry (DSC). Adding 10% of NGO to AP decreases the decomposition temperature by 106 °C and increases the apparent decomposition heat from 875 to 3236 J/g

  12. Stripping of organic compounds from wastewater as an auxiliary fuel of regenerative thermal oxidizer

    International Nuclear Information System (INIS)

    Chang, Meng-Wen; Chern, Jia-Ming

    2009-01-01

    Organic solvents with different volatilities are widely used in various processes and generate air and water pollution problems. In the cleaning processes of electronics industries, most volatile organic compounds (VOCs) are vented to air pollution control devices while most non-volatile organic solvents dissolve in the cleaning water and become the major sources of COD in wastewater. Discharging a high-COD wastewater stream to wastewater treatment facility often disturbs the treatment performance. A pretreatment of the high-COD wastewater is therefore highly desirable. This study used a packed-bed stripping tower in combination with a regenerative thermal oxidizer to remove the COD in the wastewater from a printed circuit board manufacturing process and to utilize the stripped organic compounds as the auxiliary fuel of the RTO. The experimental results showed that up to 45% of the COD could be removed and 66% of the RTO fuel could be saved by the combined treatment system.

  13. The Influence of the Interlayer Distance on the Performance of Thermally Reduced Graphene Oxide Supercapacitors

    Directory of Open Access Journals (Sweden)

    Jun-Hong Lin

    2018-02-01

    Full Text Available In this paper, cationic surfactant cetyltrimethylammonium bromide (CTAB was employed to prevent the restack of the thermally reduce graphene oxide (TRG sheets. A facile approach was demonstrated to effectively enlarge the interlayer distance of the TRG sheets through the ionic interaction between the intercalated CTAB and ionic liquids (ILs. The morphology of the composites and the interaction between the intercalated ionic species were systematically characterized by SEM, SAXS, XRD, TGA, and FTIR. In addition, the performance of the EDLC cells based on these TRG composites was evaluated. It was found that due to the increased interlayer distance (0.41 nm to 2.51 nm that enlarges the accessible surface area for the IL electrolyte, the energy density of the cell can be significantly improved (23.1 Wh/kg to 62.5 Wh/kg.

  14. Thermally Reduced Graphene Oxide Electrochemically Activated by Bis-Spiro Quaternary Alkyl Ammonium for Capacitors.

    Science.gov (United States)

    He, Tieshi; Meng, Xiangling; Nie, Junping; Tong, Yujin; Cai, Kedi

    2016-06-08

    Thermally reduced graphene oxide (RGO) electrochemically activated by a quaternary alkyl ammonium-based organic electrolytes/activated carbon (AC) electrode asymmetric capacitor is proposed. The electrochemical activation process includes adsorption of anions into the pores of AC in the positive electrode and the interlayer intercalation of cations into RGO in the negative electrode under high potential (4.0 V). The EA process of RGO by quaternary alkyl ammonium was investigated by X-ray diffraction and electrochemical measurements, and the effects of cation size and structure were extensively evaluated. Intercalation by quaternary alkyl ammonium demonstrates a small degree of expansion of the whole crystal lattice (d002) and a large degree of expansion of the partial crystal lattice (d002) of RGO. RGO electrochemically activated by bis-spiro quaternary alkyl ammonium in propylene carbonate/AC asymmetric capacitor exhibits good activated efficiency, high specific capacity, and stable cyclability.

  15. Thermal oxidation of seeds for the hydrothermal growth of WO{sub 3} nanorods on ITO glass substrate

    Energy Technology Data Exchange (ETDEWEB)

    Ng, Chai Yan [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Department of Mechanical and Material Engineering, Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Sungai Long, Bandar Sungai Long, Cheras, 43000 Kajang, Selangor (Malaysia); Abdul Razak, Khairunisak, E-mail: khairunisak@usm.my [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); NanoBiotechnology Research and Innovation (NanoBRI), Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Lockman, Zainovia, E-mail: zainovia@usm.my [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia)

    2015-11-30

    This work reports a simple seed formation method for the hydrothermal growth of tungsten oxide (WO{sub 3}) nanorods. A WO{sub 3} seed layer was prepared by thermal oxidation, where a W-sputtered substrate was heated and oxidized in a furnace. Oxidation temperatures and periods were varied at 400–550 °C and 5–60 min, respectively, to determine an appropriate seed layer for nanorod growth. Thermal oxidation at 500 °C for 15 min was found to produce a seed layer with sufficient crystallinity and good adhesion to the substrate. These properties prevented the seed from peeling off during the hydrothermal process, thereby allowing nanorod growth on the seed. The nanorod film showed better electrochromic behavior (higher current density of − 1.11 and + 0.65 mA cm{sup −2}) than compact film (lower current density of − 0.54 and + 0.28 mA cm{sup −2}). - Highlights: • A simple seed formation method (thermal oxidation) on sputtered W film is reported. • Crystalline seed with good adhesion to substrate is required for nanorod growth. • The appropriate temperature and period for seed formation were 500 °C and 15 min. • WO{sub 3} nanorods exhibited higher electrochromic current density than WO{sub 3} compact film.

  16. Determination of Polybutadiene Unsaturation Content in Thermal and Thermo-Oxidative Degradation Processes by NMR

    Directory of Open Access Journals (Sweden)

    Farshid Ziaee

    2013-01-01

    Full Text Available The unsaturation content of various polybutadiene (PBD types of 1,4-cis, 1,4-trans and 1,2-vinyl isomers with different molecular weights was investigated. An important parameter for unsaturation content of polybutadiene would be the determination of olefnic and aliphatic contents for three types of isomers. For this purpose, proton and carbon nuclear magnetic resonance spectroscopy methods were employed for determination of 1,4-cis, 1,4-trans and 1,2-vinyl contents. A change of adjustable parameter of NMR software was made for accurate integrals giving better results. The accuracy in calculation of low molecular weight PBD, surface area of chain end group decreased in aliphatic region. Furthermore, the changing of unsaturation content versus time was considered for 1,2-PBD and 1,4-PBD in thermal degradation conditions at 250°C. NMR results showed that during heating, the unsaturation content decreased for 1,2-PBD and was not changed for 1,4-PBD. In fact, the basic factor responsible for changing of unsaturation content in thermal degradation of PBD may be due to the presence of 1,2-vinyl isomer. Finally, changing in unsaturation content versus time was observed for 1,2-PBD and 1,4-PBD in thermo-oxidative degradation conditions at 100°C. The NMR results showed that at extended time, the unsaturation content decreased for 1,4-PBD and was not changed for 1,2-PBD. Moreover, the basic factor for changes in unsaturation content in thermo-oxidative degradation of PBD is due to the presence of 1,4-cis and 1,4-trans isomers.

  17. In-depth investigation of spin-on doped solar cells with thermally grown oxide passivation

    Science.gov (United States)

    Ahmad, Samir Mahmmod; Cheow, Siu Leong; Ludin, Norasikin A.; Sopian, K.; Zaidi, Saleem H.

    Solar cell industrial manufacturing, based largely on proven semiconductor processing technologies supported by significant advancements in automation, has reached a plateau in terms of cost and efficiency. However, solar cell manufacturing cost (dollar/watt) is still substantially higher than fossil fuels. The route to lowering cost may not lie with continuing automation and economies of scale. Alternate fabrication processes with lower cost and environmental-sustainability coupled with self-reliance, simplicity, and affordability may lead to price compatibility with carbon-based fuels. In this paper, a custom-designed formulation of phosphoric acid has been investigated, for n-type doping in p-type substrates, as a function of concentration and drive-in temperature. For post-diffusion surface passivation and anti-reflection, thermally-grown oxide films in 50-150-nm thickness were grown. These fabrication methods facilitate process simplicity, reduced costs, and environmental sustainability by elimination of poisonous chemicals and toxic gases (POCl3, SiH4, NH3). Simultaneous fire-through contact formation process based on screen-printed front surface Ag and back surface through thermally grown oxide films was optimized as a function of the peak temperature in conveyor belt furnace. Highest efficiency solar cells fabricated exhibited efficiency of ∼13%. Analysis of results based on internal quantum efficiency and minority carried measurements reveals three contributing factors: high front surface recombination, low minority carrier lifetime, and higher reflection. Solar cell simulations based on PC1D showed that, with improved passivation, lower reflection, and high lifetimes, efficiency can be enhanced to match with commercially-produced PECVD SiN-coated solar cells.

  18. Nitric oxide synthase modulates CFA-induced thermal hyperalgesia through cytokine regulation in mice.

    Science.gov (United States)

    Chen, Yong; Boettger, Michael K; Reif, Andreas; Schmitt, Angelika; Uçeyler, Nurcan; Sommer, Claudia

    2010-03-02

    Although it has been largely demonstrated that nitric oxide synthase (NOS), a key enzyme for nitric oxide (NO) production, modulates inflammatory pain, the molecular mechanisms underlying these effects remain to be clarified. Here we asked whether cytokines, which have well-described roles in inflammatory pain, are downstream targets of NO in inflammatory pain and which of the isoforms of NOS are involved in this process. Intraperitoneal (i.p.) pretreatment with 7-nitroindazole sodium salt (7-NINA, a selective neuronal NOS inhibitor), aminoguanidine hydrochloride (AG, a selective inducible NOS inhibitor), L-N(G)-nitroarginine methyl ester (L-NAME, a non-selective NOS inhibitor), but not L-N(5)-(1-iminoethyl)-ornithine (L-NIO, a selective endothelial NOS inhibitor), significantly attenuated thermal hyperalgesia induced by intraplantar (i.pl.) injection of complete Freund's adjuvant (CFA). Real-time reverse transcription-polymerase chain reaction (RT-PCR) revealed a significant increase of nNOS, iNOS, and eNOS gene expression, as well as tumor necrosis factor-alpha (TNF), interleukin-1 beta (IL-1beta), and interleukin-10 (IL-10) gene expression in plantar skin, following CFA. Pretreatment with the NOS inhibitors prevented the CFA-induced increase of the pro-inflammatory cytokines TNF and IL-1beta. The increase of the anti-inflammatory cytokine IL-10 was augmented in mice pretreated with 7-NINA or L-NAME, but reduced in mice receiving AG or L-NIO. NNOS-, iNOS- or eNOS-knockout (KO) mice had lower gene expression of TNF, IL-1beta, and IL-10 following CFA, overall corroborating the inhibitor data. These findings lead us to propose that inhibition of NOS modulates inflammatory thermal hyperalgesia by regulating cytokine expression.

  19. Nitric oxide synthase modulates CFA-induced thermal hyperalgesia through cytokine regulation in mice

    Directory of Open Access Journals (Sweden)

    Üçeyler Nurcan

    2010-03-01

    Full Text Available Abstract Background Although it has been largely demonstrated that nitric oxide synthase (NOS, a key enzyme for nitric oxide (NO production, modulates inflammatory pain, the molecular mechanisms underlying these effects remain to be clarified. Here we asked whether cytokines, which have well-described roles in inflammatory pain, are downstream targets of NO in inflammatory pain and which of the isoforms of NOS are involved in this process. Results Intraperitoneal (i.p. pretreatment with 7-nitroindazole sodium salt (7-NINA, a selective neuronal NOS inhibitor, aminoguanidine hydrochloride (AG, a selective inducible NOS inhibitor, L-N(G-nitroarginine methyl ester (L-NAME, a non-selective NOS inhibitor, but not L-N(5-(1-iminoethyl-ornithine (L-NIO, a selective endothelial NOS inhibitor, significantly attenuated thermal hyperalgesia induced by intraplantar (i.pl. injection of complete Freund's adjuvant (CFA. Real-time reverse transcription-polymerase chain reaction (RT-PCR revealed a significant increase of nNOS, iNOS, and eNOS gene expression, as well as tumor necrosis factor-alpha (TNF, interleukin-1 beta (IL-1β, and interleukin-10 (IL-10 gene expression in plantar skin, following CFA. Pretreatment with the NOS inhibitors prevented the CFA-induced increase of the pro-inflammatory cytokines TNF and IL-1β. The increase of the anti-inflammatory cytokine IL-10 was augmented in mice pretreated with 7-NINA or L-NAME, but reduced in mice receiving AG or L-NIO. NNOS-, iNOS- or eNOS-knockout (KO mice had lower gene expression of TNF, IL-1β, and IL-10 following CFA, overall corroborating the inhibitor data. Conclusion These findings lead us to propose that inhibition of NOS modulates inflammatory thermal hyperalgesia by regulating cytokine expression.

  20. Effects of thermal aging on thermo-mechanical behavior of a glass sealant for solid oxide cell applications

    DEFF Research Database (Denmark)

    Abdoli, Hamid; Alizadeh, Parvin; Boccaccini, Dino

    2014-01-01

    Thermo-mechanical properties of a silicate based glass and its potential use for sealing application in intermediate temperature solid oxide cell (SOC) are presented in this paper. Effects of thermal aging are discussed on structural and microstructural evolution, thermal expansion, viscosity......'s modulus in which a transition between a slow softening (elastic) regime and a rapid softening one was observed. Crystallization induced by thermal aging led to higher creep resistance, but lower capability of crack healing when inspected by electron microscopy. However, potential of stress relaxation...

  1. Effect of Thermal Processing towards Lipid Oxidation and Non-enzymatic Browning Reactions of Antartic Krill (Euphausia superba) Meal.

    Science.gov (United States)

    Liu, Yanzi; Cong, Peixu; Li, Beijia; Song, Yu; Liu, Yanjun; Xu, Jie; Xue, Changhu

    2018-04-13

    Antarctic krill is a huge source of biomass and prospective high-quality lipid source. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), nutritionally important lipid components with poor oxidative stability, were used as markers of oxidation during thermal processing of Antarctic krill (Euphausia superba) meal by evaluating the lipolysis, lipid oxidation, and non-enzymatic browning reactions. Liquid chromatography-mass spectrometry of the phospholipids (PLs) and the main oxidation products of free fatty acids (FFAs) and phosphatidylcholine (PC) was effective for evaluating the oxidation of EPA and DHA. During boiling, oxidation of EPA and DHA in the FFA and PC fractions and hydrolysis of the fatty acids at the sn-2 position of the PLs were predominant. The changes in PC during drying were mainly attributed to the oxidation of EPA and DHA. Heat treatment increased the oxidation products and concentration of hydrophobic pyrrole owing to pyrrolization between phosphatidylethanolamine (PE) and the lipid oxidation products. The lipid oxidation level of Antarctic krill increased after drying, owing to prolonged heating under the severe conditions. This article is protected by copyright. All rights reserved.

  2. Ultrasound assisted simultaneous reduction and direct functionalization of graphene oxide with thermal and cytotoxicity profile.

    Science.gov (United States)

    Maktedar, Shrikant S; Avashthi, Gopal; Singh, Man

    2017-01-01

    The new sonochemical approach for simultaneous reduction and direct functionalization of graphene oxide (GrO) has been developed. The GrO was functionalized with 2-Aminobenzoxazole (2-ABOZ) in twenty min with complete deletion of hazardous steps. The significance of ultrasound was exemplified with the comparative conventional methods. The newly prepared f-(2-ABOZ)GrO was extensively characterized with near edge X-ray absorption fine structure (NEXAFS) spectroscopy, 13 C solid state NMR, XPS, XRD, HRTEM, SAED, AFM, Raman, UV-vis, FTIR and TGA. The thermal stability of f-(2-ABOZ)GrO was confirmed with total percentage weight loss in TGA. The biological activity of f-(2-ABOZ)GrO was explored with MCF-7 and Vero cell lines. The inherent cytotoxicity was evaluated with SRB assay at 10, 20, 40 and 80μgmL -1 . The estimated cell viabilities were >78% with f-(2-ABOZ) GrO. A high cytocompatibility of f-(2-ABOZ)GrO was ensured with in vitro evaluation on living cell lines, and low toxicity of f-(2-ABOZ)GrO was confirmed its excellent biocompatibility. The morphological effect on Vero cell line evidently supports the formation of biocompatible f-(2-ABOZ)GrO. Therefore, f-(2-ABOZ)GrO was emerged as an advanced functional material for thermally stable biocompatible coatings. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Structural, optoelectronic, luminescence and thermal properties of Ga-doped zinc oxide thin films

    International Nuclear Information System (INIS)

    Shinde, S.S.; Shinde, P.S.; Oh, Y.W.; Haranath, D.; Bhosale, C.H.; Rajpure, K.Y.

    2012-01-01

    Highlights: ► The ecofriendly deposition of Ga-doped zinc oxide. ► Influence of Ga doping onto physicochemical properties in aqueous media. ► Electron–phonon coupling by Raman. ► Chemical bonding structure and valence band analysis by XPS. - Abstract: Ga-doped ZnO thin films are synthesized by chemical spray pyrolysis onto corning glass substrates in aqueous media. The influence of gallium doping on to the photoelectrochemical, structural, Raman, XPS, morphological, optical, electrical, photoluminescence and thermal properties have been investigated in order to achieve good quality films. X-ray diffraction study depicts the films are polycrystalline and fit well with hexagonal (wurtzite) crystal structure with strong orientations along the (0 0 2) and (1 0 1) planes. Presence of E 2 high mode in Raman spectra indicates that the gallium doping does not change the wurtzite structure. The coupling strength between electron and LO phonon has experimentally estimated. In order to understand the chemical bonding structure and electronic states of the Ga-doped ZnO thin films XPS analysis have been studied. SEM images shows the films are adherent, compact, densely packed with hexagonal flakes and spherical grains. Optical transmittance and reflectance measurements have been carried out. Room temperature PL spectra depict violet, blue and green emission in deposited films. The specific heat and thermal conductivity study shows the phonon conduction behavior is dominant in these polycrystalline films.

  4. Nitrogen oxides emissions from thermal power plants in china: current status and future predictions.

    Science.gov (United States)

    Tian, Hezhong; Liu, Kaiyun; Hao, Jiming; Wang, Yan; Gao, Jiajia; Qiu, Peipei; Zhu, Chuanyong

    2013-10-01

    Increasing emissions of nitrogen oxides (NOx) over the Chinese mainland have been of great concern due to their adverse impacts on regional air quality and public health. To explore and obtain the temporal and spatial characteristics of NOx emissions from thermal power plants in China, a unit-based method is developed. The method assesses NOx emissions based on detailed information on unit capacity, boiler and burner patterns, feed fuel types, emission control technologies, and geographical locations. The national total NOx emissions in 2010 are estimated at 7801.6 kt, of which 5495.8 kt is released from coal-fired power plant units of considerable size between 300 and 1000 MW. The top provincial emitter is Shandong where plants are densely concentrated. The average NOx-intensity is estimated at 2.28 g/kWh, markedly higher than that of developed countries, mainly owing to the inadequate application of high-efficiency denitrification devices such as selective catalytic reduction (SCR). Future NOx emissions are predicted by applying scenario analysis, indicating that a reduction of about 40% by the year 2020 can be achieved compared with emissions in 2010. These results suggest that NOx emissions from Chinese thermal power plants could be substantially mitigated within 10 years if reasonable control measures were implemented effectively.

  5. Radio-frequency magnetron sputtering and wet thermal oxidation of ZnO thin film

    International Nuclear Information System (INIS)

    Liu, H. F.; Chua, S. J.; Hu, G. X.; Gong, H.; Xiang, N.

    2007-01-01

    The authors studied the growth and wet thermal oxidation (WTO) of ZnO thin films using a radio-frequency magnetron sputtering technique. X-ray diffraction reveals a preferred orientation of [1010]ZnO(0002)//[1120]Al 2 O 3 (0002) coexisted with a small amount of ZnO (1011) and ZnO (1013) crystals on the Al 2 O 3 (0001) substrate. The ZnO (1011) and ZnO (1013) crystals, as well as the in-plane preferred orientation, are absent from the growth of ZnO on the GaAs(001) substrate. WTO at 550 deg. C improves the crystalline and the photoluminescence more significantly than annealing in air, N 2 and O 2 ambient; it also tends to convert the crystal from ZnO (1011) and ZnO (1013) to ZnO (0002). The evolution of the photoluminescence upon WTO and annealing reveals that the green and orange emissions, centered at 520 and 650 nm, are likely originated from oxygen vacancies and oxygen interstitials, respectively; while the 420 nm emission, which is very sensitive to the postgrowth thermal processing regardless of the substrate and the ambient gas, is likely originated from the surface-state related defects

  6. Chemical and Radiochemical Composition of Thermally Stabilized Plutonium Oxide from the Plutonium Finishing Plant Considered as Alternate Feedstock for the Mixed Oxide Fuel Fabrication Facility

    International Nuclear Information System (INIS)

    Tingey, Joel M.; Jones, Susan A.

    2005-01-01

    Eighteen plutonium oxide samples originating from the Plutonium Finishing Plant (PFP) on the Hanford Site were analyzed to provide additional data on the suitability of PFP thermally stabilized plutonium oxides and Rocky Flats oxides as alternate feedstock to the Mixed Oxide Fuel Fabrication Facility (MFFF). Radiochemical and chemical analyses were performed on fusions, acid leaches, and water leaches of these 18 samples. The results from these destructive analyses were compared with nondestructive analyses (NDA) performed at PFP and the acceptance criteria for the alternate feedstock. The plutonium oxide materials considered as alternate feedstock at Hanford originated from several different sources including Rocky Flats oxide, scrap from the Remote Mechanical C-Line (RMC) and the Plutonium Reclamation Facility (PRF), and materials from other plutonium conversion processes at Hanford. These materials were received at PFP as metals, oxides, and solutions. All of the material considered as alternate feedstock was converted to PuO2 and thermally stabilized by heating the PuO2 powder at 950 C in an oxidizing environment. The two samples from solutions were converted to PuO2 by precipitation with Mg(OH)2. The 18 plutonium oxide samples were grouped into four categories based on their origin. The Rocky Flats oxide was divided into two categories, low- and high-chloride Rocky Flats oxides. The other two categories were PRF/RMC scrap oxides, which included scrap from both process lines and oxides produced from solutions. The two solution samples came from samples that were being tested at Pacific Northwest National Laboratory because all of the plutonium oxide from solutions at PFP had already been processed and placed in 3013 containers. These samples originated at the PFP and are from plutonium nitrate product and double-pass filtrate solutions after they had been thermally stabilized. The other 16 samples originated from thermal stabilization batches before canning at

  7. Thermally induced growth of ZnO nanocrystals on mixed metal oxide surfaces.

    Science.gov (United States)

    Inayat, Alexandra; Makky, Ayman; Giraldo, Jose; Kuhnt, Andreas; Busse, Corinna; Schwieger, Wilhelm

    2014-06-23

    An in situ method for the growth of ZnO nanocrystals on Zn/Al mixed metal oxide (MMO) surfaces is presented. The key to this method is the thermal treatment of Zn/Al layered double hydroxides (Zn/Al LDHs) in the presence of nitrate anions, which results in partial demixing of the LDH/MMO structure and the subsequent crystallization of ZnO crystals on the surface of the forming MMO layers. In a first experimental series, thermal treatment of Zn/Al LDHs with different fractions of nitrate and carbonate in the interlayer space was examined by thermogravimetry coupled with mass spectrometry (TG-MS) and in situ XRD. In a second experimental series, Zn/Al LDHs with only carbonate in the interlayer space were thermally treated in the presence of different amounts of an external nitrate source (NH4NO3). All obtained Zn/Al MMO samples were analysed by electron microscopy, nitrogen physisorption and powder X-ray diffraction. The gas phase formed during nitrate decomposition turned out to be responsible for the formation of crystalline ZnO nanoparticles. Accordingly, both interlayer nitrate and the presence of ammonium nitrate led to the formation of supported ZnO nanocrystals with mean diameters between 100 and 400 nm, and both methods offer the possibility to tailor the amount and size of the ZnO crystals by means of the amount of nitrate. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Enhanced performance of thermal-assisted electron field emission based on barium oxide nanowire

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Yunkang [Department of Mathematics and Physics, Nanjing Institute of technology, Nanjing, 211167 (China); Chen, Jing, E-mail: chenjingmoon@gmail.com [School of Electronic Science & Engineering, Southeast University, Nanjing, 210096 (China); Zhang, Yuning; Zhang, Xiaobing; Lei, Wei; Di, Yunsong [School of Electronic Science & Engineering, Southeast University, Nanjing, 210096 (China); Zhang, Zichen, E-mail: zz241@ime.ac.cn [Integrated system for Laser applications Group, Institute of Microelectronics of Chinese Academy of Sciences, 100029, Beijing (China)

    2017-02-28

    Highlights: • A possible mechanism for thermal-assisted electric field was demonstrated. • A new path for the architecture of the novel nanomaterial and methodology for its potential application in the field emission device area was provided. • The turn-on field, the threshold field and the field emission current density were largely related to the temperature of the cathode. • The relationship between the work function of emitter material and the temperature of emitter was found. - Abstract: In this paper, thermal-assisted field emission properties of barium oxide (BaO) nanowire synthesized by a chemical bath deposition method were investigated. The morphology and composition of BaO nanowire were characterized by field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SED), X-ray diffraction (XRD), and energy dispersive X-ray spectrometer (EDX) respectively. The turn-on field, threshold field and the emission current density could be affected relatively due to the thermal-assisted effect when the electric field was applied, in the meanwhile, the turn-on field for BaO nanowire was measured to be decreased from 1.12 V/μm to 0.66 V/μm when the temperature was raised from 293 K to 593 K, whereas for the threshold field was found to decrease from 3.64 V/μm to 2.12 V/μm. The improved performance was demonstrated due to the reduced work function of the BaO nanowire as the agitation temperature increasing, leading to the higher probability of electrons tunneling through the energy barrier and enhancement of the field emission properties of BaO emitters.

  9. Enhanced performance of thermal-assisted electron field emission based on barium oxide nanowire

    International Nuclear Information System (INIS)

    Cui, Yunkang; Chen, Jing; Zhang, Yuning; Zhang, Xiaobing; Lei, Wei; Di, Yunsong; Zhang, Zichen

    2017-01-01

    Highlights: • A possible mechanism for thermal-assisted electric field was demonstrated. • A new path for the architecture of the novel nanomaterial and methodology for its potential application in the field emission device area was provided. • The turn-on field, the threshold field and the field emission current density were largely related to the temperature of the cathode. • The relationship between the work function of emitter material and the temperature of emitter was found. - Abstract: In this paper, thermal-assisted field emission properties of barium oxide (BaO) nanowire synthesized by a chemical bath deposition method were investigated. The morphology and composition of BaO nanowire were characterized by field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SED), X-ray diffraction (XRD), and energy dispersive X-ray spectrometer (EDX) respectively. The turn-on field, threshold field and the emission current density could be affected relatively due to the thermal-assisted effect when the electric field was applied, in the meanwhile, the turn-on field for BaO nanowire was measured to be decreased from 1.12 V/μm to 0.66 V/μm when the temperature was raised from 293 K to 593 K, whereas for the threshold field was found to decrease from 3.64 V/μm to 2.12 V/μm. The improved performance was demonstrated due to the reduced work function of the BaO nanowire as the agitation temperature increasing, leading to the higher probability of electrons tunneling through the energy barrier and enhancement of the field emission properties of BaO emitters.

  10. Tribological performance of titanium samples oxidized by fs-laser radiation, thermal heating, or electrochemical anodization

    Science.gov (United States)

    Kirner, S. V.; Slachciak, N.; Elert, A. M.; Griepentrog, M.; Fischer, D.; Hertwig, A.; Sahre, M.; Dörfel, I.; Sturm, H.; Pentzien, S.; Koter, R.; Spaltmann, D.; Krüger, J.; Bonse, J.

    2018-04-01

    Commercial grade-1 titanium samples (Ti, 99.6%) were treated using three alternative methods, (i) femtosecond laser processing, (ii) thermal heat treatment, and (iii) electrochemical anodization, respectively, resulting in the formation of differently conditioned superficial titanium oxide layers. The laser processing (i) was carried out by a Ti:sapphire laser (pulse duration 30 fs, central wavelength 790 nm, pulse repetition rate 1 kHz) in a regime of generating laser-induced periodic surface structures (LIPSS). The experimental conditions (laser fluence, spatial spot overlap) were optimized in a sample-scanning setup for the processing of several square-millimeters large surface areas covered homogeneously by these nanostructures. The differently oxidized titanium surfaces were characterized by optical microscopy, micro Raman spectroscopy, variable angle spectroscopic ellipsometry, and instrumented indentation testing. The tribological performance was characterized in the regime of mixed friction by reciprocating sliding tests against a sphere of hardened steel in fully formulated engine oil as lubricant. The specific tribological performance of the differently treated surfaces is discussed with respect to possible physical and chemical mechanisms.

  11. Effect of cuprous oxide with different sizes on thermal and combustion behaviors of unsaturated polyester resin.

    Science.gov (United States)

    Hou, Yanbei; Hu, Weizhao; Gui, Zhou; Hu, Yuan

    2017-07-15

    Cuprous oxide (Cu 2 O) as an effective catalyst has been applied to enhance the fire safety of unsaturated polyester resin (UPR), but the particle size influence on combustion behaviors has not been previously reported. Herein, the UPR/Cu 2 O composites (metal oxide particles with average particle-size of 10, 100, and 200nm) were successfully synthesized by thermosetting process. The effects of Cu 2 O with different sizes on thermostability and combustion behaviors of UPR were characterized by TGA, MCC, TG-IR, FTIR, and SSTF. The results revel that the addition of Cu 2 O contributes to sufficient decomposition of oxygen-containing compounds, which is beneficial to the release of nontoxic compounds. The smallest-sized Cu 2 O performs the excellent catalytic decomposition effect and promotes the complete combustion of UPR, which benefits the enhancement of fire safety. While the other additives retard pyrolysis process and yield more char residue, and thus the flame retardancy of UPR composites was improved. Therefore, catalysis plays a major role for smaller-sized particles during thermal decomposition of matrix, while flame retarded effect became gradual distinctly for the larger-sized additives. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Direct chemical oxidation: a non-thermal technology for the destruction of organic wastes

    Energy Technology Data Exchange (ETDEWEB)

    Balazs, G.B.; Cooper, J. F.; Lewis, P. R.; Adamson, M. G.

    1998-02-01

    Direct Chemical Oxidation (DCO) is a non-thermal, ambient pressure, aqueous-based technology for the oxidative destruction of the organic components of hazardous or mixed waste streams. The process has been developed for applications in waste treatment and chemical demilitarization and decontamination at LLNL since 1992, and is applicable to the destruction of virtually all solid or liquid organics, including: chlorosolvents, oils and greases, detergents, organic-contaminated soils or sludges, explosives, chemical and biological warfare agents, and PCB's. [1-15] The process normally operates at 80-100 C, a heating requirement which increases the difficulty of surface decontamination of large objects or, for example, treatment of a wide area contaminated soil site. The driver for DCO work in FY98 was thus to investigate the use of catalysts to demonstrate the effectiveness of the technology for organics destruction at temperatures closer to ambient. In addition, DCO is at a sufficiently mature stage of development that technology transfer to a commercial entity was a logical next step, and was thus included in FY98 tasks.

  13. Metal-Carbon Interactions on Reduced Graphene Oxide under Facile Thermal Treatment: Microbiological and Cell Assay

    Directory of Open Access Journals (Sweden)

    N. L. V. Carreño

    2017-01-01

    Full Text Available Silver-functionalized reduced graphene oxide (Ag-rGO nanosheets were prepared by single chemical and thermal processes, with very low concentration of silver. The resulting carbon framework consists of reduced graphene oxide (rGO sheets or 3D networks, decorated with anchored silver nanoparticles. The Ag-rGO nanosheets were dispersed into a polymer matrix and the composites evaluated for use as biological scaffolds. The rGO material in poly(dimethylsiloxane (PDMS has been tested for antimicrobial activity against Gram-positive Staphylococcus aureus (S. Aureus bacteria, after exposure times of 24 and 120 hours, as well as in the determination of cell viability on cultures of fibroblast cells (NIH/3T3. Using 1 mL of Ag-rGO in PDMS the antibacterial effectiveness against Staphylococcus aureus was limited, showing an increased amount of Colony Forming Units (CFU, after 24 hours of contact. In the cell viability assay, after 48 hours of contact, the group of 1 mL of Ag-rGO with PDMS was the only group that increased cell viability when compared to the control group. In this context, it is believed these behaviors are due to the increase in cell adhesion capacity promoted by the rGO. Thus, the Ag-rGO/PDMS hybrid nanocomposite films can be used as scaffolds for tissue engineering, as they limit antimicrobial activity.

  14. Evaluation of Thermal Oxidative Aging Effect on the Rheological Performance of Modified Asphalt Binders

    Science.gov (United States)

    Zhu, Cheng

    Modified asphalt binder, which is combined by base binder and additive modifier, has been implemented in pavement industry for more than 30 years. Recently, the oxidative aging mechanism of asphalt binder has been studied for several decades, and appreciable finding results of asphalt binder aging mechanism were achieved from the chemistry and rheological performance aspects. However, most of these studies were conducted with neat binders, the research of aging mechanism of modified asphalt binder was limited. Nowadays, it is still highly necessary to clarify how the asphalt binder aging happens with the modified asphalt binder, what is the effect of the different modifiers (additives) on the binder aging process, how the rheological performance changes under the thermal oxidative aging conditions and so on. The objective of this study was to investigate the effect of isothermal oxidative aging conditions on the rheological performance change of the modified and controlled asphalt binders. There were totally 14 different sorts of asphalt binders had been aged in the PAV pans in the air-force drafted ovens at 50°C, 60°C and 85°C for 0.5 day to 240 days. The Fourier-Transform Infrared Spectroscopy (FT-IR) and Dynamic Shear Rheometer (DSR) were used to perform the experiments. The analysis of rheological indices (Low shear viscosity-LSV, Crossover modulus-G*c, Glover-Rowe Parameter-G-R, DSR function-DSR Fn) as a function of carbonyl area (CA) was conducted. With the SBS modification, both of the hardening susceptibility of the rheological index-LSV and G-R decreases compared with the corresponding base binder. The TR increased the hardening susceptibility of all the rheological indexes. While for the G*c, SBS increases the slope of the most modified asphalt binders except A and B_TR_X series binders. The multiple linear regression statistical analysis results indicate that the oxidative aging conditions play an important role on the CA, and rheological performance

  15. Product-Improvement Test (Phase II), Jetcal Tester, Model H119A.

    Science.gov (United States)

    1969-03-05

    Ao—A0 51 113 ARMY AVIATION ‘Cs’ BOARD FORT tUCKER ALA — P*OOUCTeII ROVEMCNT TEST ( FHAS ~ I I ) . JETCAL TESTER, MODEL M119A~~’ETC(U) MAR S9...Phase i i ) , Jetcal Tester , Model H 119A , USATECOM Project No. 4-6-5011-03 b . No fur ther consideration be given to the TEMPCAL heater probe as a...essen t i a l component of the Jetcal Tester. e. The service manual instruct ions for con t inu i ty te s t ing of EG1 thermocouples be revised to

  16. Tester of the TRT front-end electronics for the ATLAS-experiment

    CERN Document Server

    Hajduk, Z; Kisielewski, B; Kotarba, A; Malecki, P; Natkaniec, Z; Olszowska, J; Ostrowicz, W; Krupinska, G

    2000-01-01

    The VME based tester for front-end electronics of the TRT (Transition Radiation Tracker) detector of the ATLAS-LHC experiment at CERN, Geneva, is described. The TRT read-out electronics for 424576 proportional tubes grouped on many thousands of cards requires stringent quality control after assembly and during installation. The tester provides all required data, pulses, timing and power supplies for tested cards. The essential part of the tester is its software that allows for device handling as well as facilitates functional and statistical tests. The prototype, present design as well as the new design for mass production tests are discussed. (17 refs).

  17. Growth and structure of rapid thermal silicon oxides and nitroxides studied by spectroellipsometry and Auger electron spectroscopy

    Science.gov (United States)

    Gonon, N.; Gagnaire, A.; Barbier, D.; Glachant, A.

    1994-11-01

    Rapid thermal oxidation of Czochralski-grown silicon in either O2 or N2O atmospheres have been studied using spectroellipsometry and Auger electron spectroscopy. Multiwavelength ellipsometric data were processed in order to separately derive the thickness and refractive indexes of rapid thermal dielectrics. Results revealed a significant increase of the mean refractive index as the film thickness falls below 20 nm for both O2 or N2O oxidant species. A multilayer structure including an about 0.3-nm-thick interfacial region of either SiO(x) or nitroxide in the case of O2 and N2O growth, respectively, followed by a densified SiO2 layer, was found to accurately fit the experimental data. The interfacial region together with the densified state of SiO2 close to the interface suggest a dielectric structure in agreement with the continuous random network model proposed for classical thermal oxides. Auger electron spectroscopy analysis confirmed the presence of noncrystalline Si-Si bonds in the interfacial region, mostly in the case of thin oxides grown in O2. It was speculated that the initial fast growth regime was due to a transient oxygen supersaturation in the interfacial region. Besides, the self-limiting growth in N2O was confirmed and explained in agreement with several recently published data, by the early formation of a very thin nitride or oxynitride membrane in the highly densified oxide beneath the interface. The beneficial effect of direct nitrogen incorporation by rapid thermal oxidation in N2O instead of O2 for the electrical behavior of metal-oxide-semiconductor capacitors is likely a better SiO2/Si lattice accommodation through the reduction of stresses and Si-Si bonds in the interfacial region of the dielectric.

  18. Structural and microstructural changes in the zirconium-indium mixed oxide system during the thermal treatment

    Science.gov (United States)

    Štefanić, G.; Štefanić, I. I.; Musić, S.; Ivanda, M.

    2011-05-01

    The zirconium-indium mixed oxide systems on both the zirconium- and the indium-rich side of the concentration range were prepared by co-precipitation from aqueous solutions of the corresponding salts, followed by washing and heat-treatment. The thermal behavior (up to 1000 °C) of the dried samples was examined by X-ray powder diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, energy dispersive X-ray spectrometry, differential thermal analysis and thermogravimetric measurements. The obtained results show that the increase in the amount of the second phase causes an increase of both the crystallization temperature of the amorphous precursors of ZrO 2, from 435 °C (0 mol.% of InO 1.5) to 476 °C (˜62 mol.% of InO 1.5), and of the topotactic transition temperature of cubic In(OH) 3 to cubic In 2O 3, from 259 °C (0 mol.% of ZrO 2) to 290 °C (˜25 mol.% of ZrO 2). The amorphous precursors of ZrO 2 phase exhibit an extended capability to incorporate In 3+ ions (more than 60 mol.%). With a rise in temperature the maximum solubility of In 3+ ions in the ZrO 2 lattice decreases from ˜55 mol.% in the crystallization products obtained after calcination at 400 °C to ˜10 mol.% after calcination at 1000 °C. The results of phase analysis indicate that the incorporation of In 3+ ions partially stabilized both the tetragonal and cubic ZrO 2 polymorphs. The maximum solubility of Zr 4+ ions in the starting In(OH) 3 lattice was estimated at ˜10 mol.%. Thermal treatment causes a small increase of Zr 4+ ion solubility limits, estimated at ˜15 mol.% in the cubic In 2O 3 lattice after calcination at 1000 °C. Precise lattice parameter measurements, by using Le Bail refinements of the powder diffraction patterns with added silicon as an internal standard, show that the incorporation of In 3+ ions caused a very small decrease of the cubic ZrO 2 lattice, while the incorporation of Zr 4+ ions had a negligible

  19. Thermal Treatment of Iron Oxide Stabilized APC Residues from Waste Incineration and the Effect on Heavy Metal Binding

    DEFF Research Database (Denmark)

    Sørensen, Mette Abildgaard; Stackpoole, M.; Bender-Koch, C.

    2000-01-01

    Iron oxide stabilized APC residues from MSWI were heat treated at 600°C and 900°C. The thermal treatments resulted in a change in product stability by forcing a transformation in the mineralogical structures of the products. The treatments, moreover, simulated somewhat the natural aging processes...

  20. Improved thermal stability of methylsilicone resins by compositing with N-doped graphene oxide/Co3O4 nanoparticles

    International Nuclear Information System (INIS)

    Jiang, Bo; Zhao, Liwei; Guo, Jiang; Yan, Xingru; Ding, Daowei; Zhu, Changcheng; Huang, Yudong; Guo, Zhanhu

    2016-01-01

    Nanoparticles play important roles in enhancing the thermal-resistance of hosting polymer resins. Despite tremendous efforts, developing thermally stable methylsilicone resin at high temperatures is still a challenge. Herein, we report a strategy to increase the activation energy to slow down the decomposition/degradation of methylsilicone resin using synergistic effects between the Co 3 O 4 nanoparticles and the nitrogen doped graphene oxide. The N-doped graphene oxides composited with Co 3 O 4 nanoparticles were prepared by hydrolysis of cobalt nitrate hexahydrate in the presence of graphene oxide and were incorporated into the methylsilicone resin. Two-stage decompositions were observed, i.e., 200–300 and 400–500 °C. The activation energy for the low temperature region was enhanced by 47.117 kJ/mol (vs. 57.76 kJ/mol for pure resin). The enhanced thermal stability was due to the fact that the nanofillers prevented the silicone hydroxyl chain ends ‘‘biting’’ to delay the degradation. The activation energy for high-temperature region was enhanced by 11.585 kJ/mol (vs. 171.95 kJ/mol for pure resin). The nanofillers formed a protective layer to isolate oxygen from the hosting resin. The mechanism for the enhanced thermal stability through prohibited degradation with synergism of these nitrogen-doped graphene oxide nanocomposites was proposed as well.Graphical Abstract

  1. Reversible switching of wetting properties and erasable patterning of polymer surfaces using plasma oxidation and thermal treatment

    Science.gov (United States)

    Rashid, Zeeshan; Atay, Ipek; Soydan, Seren; Yagci, M. Baris; Jonáš, Alexandr; Yilgor, Emel; Kiraz, Alper; Yilgor, Iskender

    2018-05-01

    Polymer surfaces reversibly switchable from superhydrophobic to superhydrophilic by exposure to oxygen plasma and subsequent thermal treatment are demonstrated. Two inherently different polymers, hydrophobic segmented polydimethylsiloxane-urea copolymer (TPSC) and hydrophilic poly(methyl methacrylate) (PMMA) are modified with fumed silica nanoparticles to prepare superhydrophobic surfaces with roughness on nanometer to micrometer scale. Smooth TPSC and PMMA surfaces are also used as control samples. Regardless of their chemical structure and surface topography, all surfaces display completely reversible wetting behavior changing from hydrophobic to hydrophilic and back for many cycles upon plasma oxidation followed by thermal annealing. Influence of plasma power, plasma exposure time, annealing temperature and annealing time on the wetting behavior of polymeric surfaces are investigated. Surface compositions, textures and topographies are characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and white light interferometry (WLI), before and after oxidation and thermal annealing. Wetting properties of the surfaces are determined by measuring their static, advancing and receding water contact angle. We conclude that the chemical structure and surface topography of the polymers play a relatively minor role in reversible wetting behavior, where the essential factors are surface oxidation and migration of polymer molecules to the surface upon thermal annealing. Reconfigurable water channels on polymer surfaces are produced by plasma treatment using a mask and thermal annealing cycles. Such patterned reconfigurable hydrophilic regions can find use in surface microfluidics and optofluidics applications.

  2. The Development and Application of Simulative Insulation Resistance Tester

    Science.gov (United States)

    Jia, Yan; Chai, Ziqi; Wang, Bo; Ma, Hao

    2018-02-01

    The insulation state determines the performance and insulation life of electrical equipment, so it has to be judged in a timely and accurate manner. Insulation resistance test, as the simplest and most basic test of high voltage electric tests, can measure the insulation resistance and absorption ratio which are effective criterion of part or whole damp or dirty, breakdown, severe overheating aging and other insulation defects. It means that the electrical test personnel need to be familiar with the principle of insulation resistance test, and able to operate the insulation resistance tester correctly. At present, like the insulation resistance test, most of electrical tests are trained by physical devices with the real high voltage. Although this allows the students to truly experience the test process and notes on security, it also has certain limitations in terms of safety and test efficiency, especially for a large number of new staves needing induction training every year. This paper presents a new kind of electrical test training system based on the simulative device of dielectric loss measurement and simulative electrical testing devices. It can not only overcome the defects of current training methods, but also provide other advantages in economical efficiency and scalability. That makes it possible for the system to be allied in widespread.

  3. Explosive component acceptance tester using laser interferometer technology

    Science.gov (United States)

    Wickstrom, Richard D.; Tarbell, William W.

    1993-01-01

    Acceptance testing of explosive components requires a reliable and simple to use testing method that can discern less than optimal performance. For hot-wire detonators, traditional techniques use dent blocks or photographic diagnostic methods. More complicated approaches are avoided because of their inherent problems with setup and maintenance. A recently developed tester is based on using a laser interferometer to measure the velocity of flying plates accelerated by explosively actuated detonators. Unlike ordinary interferometers that monitor displacement of the test article, this device measures velocity directly and is commonly used with non-spectral surfaces. Most often referred to as the VISAR technique (Velocity Interferometer System for Any Reflecting Surface), it has become the most widely-accepted choice for accurate measurement of velocity in the range greater than 1 mm/micro-s. Traditional VISAR devices require extensive setup and adjustment and therefore are unacceptable in a production-testing environment. This paper describes a new VISAR approach which requires virtually no adjustments, yet provides data with accuracy comparable to the more complicated systems. The device, termed the Fixed-Cavity VISAR, is currently being developed to serve as a product verification tool for hot-wire detonators and slappers. An extensive data acquisition and analysis computer code was also created to automate the manipulation of raw data into final results.

  4. Shape-stabilized phase change materials with high thermal conductivity based on paraffin/graphene oxide composite

    International Nuclear Information System (INIS)

    Mehrali, Mohammad; Latibari, Sara Tahan; Mehrali, Mehdi; Metselaar, Hendrik Simon Cornelis; Silakhori, Mahyar

    2013-01-01

    Highlights: ► The composite PCM was prepared with impregnation method. ► Shapes stabilized phase change material made with paraffin and GO composite. ► Determine effects of GO composite on shape stabilized PCM properties. ► The composite PCM has good thermal stability and form-stability. ► The composite PCM has much higher thermal conductivity than that of paraffin. - Abstract: This paper mainly focuses on the preparation, characterization, thermal properties and thermal stability and reliability of new form-stable composite phase change materials (PCMs) prepared by vacuum impregnation of paraffin within graphene oxide (GO) sheets. SEM and FT-IR techniques and TGA and DSC analysis are used for characterization of material and thermal properties. The composite PCM contained 48.3 wt.% of paraffin without leakage of melted PCM and therefore this composite found to be a form-stable composite PCM. SEM results indicate that the paraffin bounded into the pores of GO. FT-IR analysis showed there was no chemical reaction between paraffin and GO. Temperatures of melting and freezing and latent heats of the composite were 53.57 and 44.59 °C and 63.76 and 64.89 kJ/kg, respectively. Thermal cycling tests were done by 2500 melting/freezing cycling for verification of the form-stable composite PCM in terms of thermal reliability and chemical stability. Thermal conductivity of the composite PCM was highly improved from 0.305 to 0.985 (W/mk). As a result, the prepared paraffin/GO composite is appropriate PCM for thermal energy storage applications because of their acceptable thermal properties, good thermal reliability, chemical stability and thermal conductivities

  5. Improved Thermally Grown Oxide Scale in Air Plasma Sprayed NiCrAlY/Nano-YSZ Coatings

    International Nuclear Information System (INIS)

    Daroonparvar, M.; Yajid, M.A.M.; Yusof, N.M.; Hussain, M.S.

    2013-01-01

    Oxidation has been considered as one of the principal disruptive factors in thermal barrier coating systems during service. So, oxidation behavior of thermal barrier coating (TBC) systems with nano structured and micro structured YSZ coatings was investigated at 1000 degree c for 24 h, 48 h, and 120 h. Air plasma sprayed nano-YSZ coating exhibited a tri modal structure. Microstructural characterization also demonstrated an improved thermally grown oxide scale containing lower spinels in nano-TBC system after 120 h of oxidation. This phenomenon is mainly related to the unique structure of the nano-YSZ coating, which acted as a strong barrier for oxygen diffusion into the TBC system at elevated temperatures. Nearly continues but thinner Al 2 O 3 layer formation at the NiCrAlY/nano-YSZ interface was seen, due to lower oxygen infiltration into the system. Under this condition, spinels formation and growth on the Al 2 O 3 oxide scale were diminished in nano-TBC system compared to normal TBC system.

  6. Influence of thermal oxidation duration on the microstructure and fretting wear behavior of Ti6Al4V alloy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Song [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Liao, Zhenhua [Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Biomechanics and Biotechnology Lab, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China); Liu, Yuhong [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Liu, Weiqiang, E-mail: weiqliu@hotmail.com [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Biomechanics and Biotechnology Lab, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China)

    2015-06-01

    Thermal oxidation under water oxidizing atmosphere was performed on Ti6Al4V alloy under different durations from 2 h to 8 h. Surface characterizations were performed using X-ray diffractometery (XRD), scanning electron microscopy (SEM), Raman spectroscopy, nanoindentation and nano scratch testing. Fretting wear behaviors of untreated and oxidized samples were also examined. The formed oxide coating mainly included rutile TiO{sub 2} as well as a little alumina. The weight gain with respect to the oxidation duration obeyed the linear oxidation kinetics law. The growth of oxide grains was in inadequate growth state of incomplete scale coverage from 2nd to 4th hour duration, in normal growth state from 4th to 6th hour duration while in excessive growth state of oxide particle agglomeration and surface roughening from 6th to 8th (or more than 8th) hour duration. The coating thickness increased from 5 μm to 12 μm as oxidation duration increased from 2 h to 8 h. The increase in duration also increased surface roughness and nano hardness as well as adhesion strength of the film/substrate for oxidized samples. The nano hardness value was 10.06 ± 2.15 GPa and the critical load of failure during nano scratch testing was 554.3 ± 6.44 mN for 4 h treated sample. The untreated and oxidized samples showed a same fretting running status and fretting regime with a displacement amplitude of 200 μm while revealing different fretting failure mechanisms. It was mainly abrasive and adhesive wear under ploughing force for untreated sample, while a mix of 3-body abrasion by rolling oxide particles and severe plastic deformation under high contact stress between two ceramic materials for the oxidized samples. The oxide coating was not worn out and improved the fretting wear resistance of titanium alloy. - Highlights: • A thickness of 5–12 μm rutile TiO{sub 2} coating formed under different oxidation durations. • Weight gain with respect to oxidation duration obeyed linear

  7. Strategies to curb structural changes of lithium/transition metal oxide cathode materials & the changes’ effects on thermal & cycling stability

    Science.gov (United States)

    Xiqian, Yu; Enyuan, Hu; Seongmin, Bak; Yong-Ning, Zhou; Xiao-Qing, Yang

    2016-01-01

    Structural transformation behaviors of several typical oxide cathode materials during a heating process are reviewed in detail to provide in-depth understanding of the key factors governing the thermal stability of these materials. We also discuss applying the information about heat induced structural evolution in the study of electrochemically induced structural changes. All these discussions are expected to provide valuable insights for designing oxide cathode materials with significantly improved structural stability for safe, long-life lithium ion batteries, as the safety of lithium-ion batteries is a critical issue; it is widely accepted that the thermal instability of the cathodes is one of the most critical factors in thermal runaway and related safety problems. Project supported by the U.S. Department of Energy, the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies (Grant No. DE-SC0012704).

  8. In Situ Analysis of the Li-O2 Battery with Thermally Reduced Graphene Oxide Cathode: Influence of Water Addition

    DEFF Research Database (Denmark)

    Storm, Mie Møller; Christensen, Mathias Kjærgård; Younesi, Reza

    2016-01-01

    The Li-O2 battery technology holds the promise to deliver a battery with significantly increased specific energy compared to today's Li-ion batteries. As a cathode support material, reduced graphene oxide has received increasing attention in the Li-O2 battery community due to the possibility...... of increased discharge capacity, increased battery cyclability, and decreased, charging, overpotential. In this. article we investigate the effect of water on a thermally, redircedigraphene, oxide cathode in a Li-O2 battery. Differential electrochemical mass spectrciscnieveals a, decreased electron count......-of-the cathode and not only on addition of water to the electrolyte as demonstrated by the solution-based mechanism In situ synchrotron X-ray diffraction experiment using a new design of a capillary-based Li-O2 cell with a thermally reduced graphene oxide cathode shows formation of LiOH along with Li2O2....

  9. NPS-SCAT (Solar Cell Array Tester), The Construction of NPS' First Prototype CubeSat

    National Research Council Canada - National Science Library

    Bein, Alexander L

    2008-01-01

    .... This Master's Thesis describes the NPS-SCAT (solar cell array tester) project, including the author's experience as program manager of the project, responsible for budget, schedule and technical deliverables...

  10. Interference of apex locator, pulp tester and diathermy on pacemaker function

    OpenAIRE

    Narayanan Sriman; V Prabhakar; J S Bhuvaneswaran; N Subha

    2015-01-01

    Aim: The purpose of this study was to evaluate the effects of three electronic apex locators (EAL), electric pulp tester (EPT) and diathermy on pacemaker function in vitro. Materials and Methods: Three EALs: Root ZX (J. Morita Co., Tustin, CA, U.S.A.), Propex (Dentsply), Mini Apex locator (SybronEndo, Anaheim, CA, USA), EPT (Parkell pulp vitality tester Farmingdale, NY, USA) and Diathermy (Neomed 250 B) were tested for any interference with one pacemaker (A medtronic kappa KVDD901-serial ...

  11. Nanocomposites of cellulose/iron oxide: influence of synthesis conditions on their morphological behavior and thermal stability

    International Nuclear Information System (INIS)

    Ma Mingguo; Zhu Jiefang; Li Shuming; Jia Ning; Sun Runcang

    2012-01-01

    Nanocomposites of cellulose/iron oxide have been successfully prepared by hydrothermal method using cellulose solution and Fe(NO 3 ) 3 ·9H 2 O at 180 °C. The cellulose solution was obtained by the dissolution of microcrystalline cellulose in NaOH/urea aqueous solution, which is a good system to dissolve cellulose and favors the synthesis of iron oxide without needing any template or other reagents. The phases, microstructure, and morphologies of nanocomposites were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectra (EDS). The effects of the heating time, heating temperature, cellulose concentration, and ferric nitrate concentration on the morphological behavior of products were investigated. The experimental results indicated that the cellulose concentration played an important role in both the phase and shape of iron oxide in nanocomposites. Moreover, the nanocomposites synthesized by using different cellulose concentrations displayed different thermal stabilities. - Highlights: ► Nanocomposites of cellulose/iron oxide have been prepared by hydrothermal method. ► The cellulose concentration played an important role in the phase of iron oxide. ► The cellulose concentration played an important role in the shape of iron oxide. ► The samples displayed different thermal stabilities.

  12. Real-time monitoring of initial thermal oxidation on Si(001) surfaces by synchrotron radiation photoemission spectroscopy

    CERN Document Server

    Yoshigoe, A; Teraoka, Y

    2003-01-01

    The thermal oxidation of Si(001) surfaces at 860 K, 895 K, 945 K and 1000 K under the O sub 2 pressure of 1 x 10 sup - sup 4 Pa has been investigated by time-resolved photoemission measurements with synchrotron radiation. Based on time evolution analyses by reaction kinetics models, it was found that the oxidation at 860 K, 895 K and 945 K has progressed with the Langmuir adsorption type, whereas the oxidation at 1000 K has showed the character of the two-dimensional island growth involving SiO desorption. The oxidation rates increases with increasing surface temperature in the passive oxidation condition. The time evolution of each Si oxidation state (Si sup n sup + : n = 1, 2, 3, 4) derived from the Si-2p core-level shifts has also been analyzed. The results revealed that the thermal energy contribution to the migration process of the adsorbed oxygen and the emission of the bulk silicon atoms. Thus, the fraction of the Si sup 4 sup + bonding state, i.e. SiO sub 2 structure, was increased. (author)

  13. Composite plasma electrolytic oxidation to improve the thermal radiation performance and corrosion resistance on an Al substrate

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Donghyun [Department of Materials Science and Engineering, Pusan National University, Busan 46241 (Korea, Republic of); Sung, Dahye [Department of Materials Science and Engineering, Pusan National University, Busan 46241 (Korea, Republic of); Korea Institute of Industrial Technology (KITECH), Busan 46742 (Korea, Republic of); Lee, Junghoon [Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ 07030 (United States); Kim, Yonghwan [Korea Institute of Industrial Technology (KITECH), Busan 46742 (Korea, Republic of); Chung, Wonsub, E-mail: wschung1@pusan.ac.kr [Department of Materials Science and Engineering, Pusan National University, Busan 46241 (Korea, Republic of)

    2015-12-01

    Highlights: • Composite plasma electrolytic oxidation was performed using dispersed CuO particles in convectional PEO electrolyte. • Thermal radiation performance and corrosion resistance were examined by FT-IR spectroscopy and electrochemical methods, respectively. • Deposited copper oxide on the surface of the Al substrate was enhanced the corrosion resistance and the emissivity compared with the conventional PEO. - Abstract: A composite plasma electrolytic oxidation (PEO) was performed for enhancing the thermal radiation performance and corrosion resistance on an Al alloy by dispersing cupric oxide (CuO) particles in a conventional PEO electrolyte. Cu-based oxides (CuO and Cu{sub 2}O) formed by composite PEO increased the emissivity of the substrate to 0.892, and made the surface being dark color, similar to a black body, i.e., an ideal radiator. In addition, the corrosion resistance was analyzed using potentio-dynamic polarization and electrochemical impedance spectroscopy tests in 3.5 wt.% NaCl aqueous solution. An optimum condition of 10 ampere per square decimeter (ASD) current density and 30 min processing time produced appropriate surface morphologies and coating thicknesses, as well as dense Cu- and Al-based oxides that constituted the coating layers.

  14. Simulation of thermal stresses in anode-supported solid oxide fuel cell stacks. Part II: Loss of gas-tightness, electrical contact and thermal buckling

    Science.gov (United States)

    Nakajo, Arata; Wuillemin, Zacharie; Van herle, Jan; Favrat, Daniel

    Structural stability issues in planar solid oxide fuel cells arise from the mismatch between the coefficients of thermal expansion of the components. The stress state at operating temperature is the superposition of several contributions, which differ depending on the component. First, the cells accumulate residual stresses due to the sintering phase during the manufacturing process. Further, the load applied during assembly of the stack to ensure electric contact and flatten the cells prevents a completely stress-free expansion of each component during the heat-up. Finally, thermal gradients cause additional stresses in operation. The temperature profile generated by a thermo-electrochemical model implemented in an equation-oriented process modelling tool (gPROMS) was imported into finite-element software (ABAQUS) to calculate the distribution of stress and contact pressure on all components of a standard solid oxide fuel cell repeat unit. The different layers of the cell in exception of the cathode, i.e. anode, electrolyte and compensating layer were considered in the analysis to account for the cell curvature. Both steady-state and dynamic simulations were performed, with an emphasis on the cycling of the electrical load. The study includes two different types of cell, operation under both thermal partial oxidation and internal steam-methane reforming and two different initial thicknesses of the air and fuel compressive sealing gaskets. The results generated by the models are presented in two papers: Part I focuses on cell cracking. In the present paper, Part II, the occurrences of loss of gas-tightness in the compressive gaskets and/or electrical contact in the gas diffusion layer were identified. In addition, the dependence on temperature of both coefficients of thermal expansion and Young's modulus of the metallic interconnect (MIC) were implemented in the finite-element model to compute the plastic deformation, while the possibilities of thermal buckling

  15. Internal photoemission study on charge trapping behavior in rapid thermal oxides on strained-Si/SiGe heterolayers

    International Nuclear Information System (INIS)

    Bera, M.K.; Mahata, C.; Bhattacharya, S.; Chakraborty, A.K.; Armstrong, B.M.; Gamble, H.S.; Maiti, C.K.

    2008-01-01

    A comparative study on the nature of defects and their relationship to charge trapping with enhanced photosensitivity has been investigated through magnetic resonance and internal photoemission (IPE) experiments for rapid thermal grown oxides (RTO) on strained-Si/Si 0.8 Ge 0.2 and on co-processed bulk-Si (1 0 0) substrates. Both the band and defect-related electronic states were characterized through EPR, IPE, C-V and I-V measurements under UV-illumination. Surface chemical characterization of as-grown ultrathin oxides (5-7 nm) has been performed using high-resolution XPS. Enhancement in Ge-segregation with increasing oxidation temperature is reported. Comparative studies on interface properties and leakage current behavior of rapid thermal oxides have also been studied through fabricating metal-oxide-semiconductor capacitor structures. A degraded electrical property with increasing oxidation temperature is reported. Constant voltage stressing (CVS) in the range of 5.5-7 V was used to study the breakdown characteristics of different samples. We observe a distinguishably different time-to-breakdown (t bd ) phenomenon for bulk-Si and strained-Si/SiGe samples. Whereas the oxide on bulk-Si shows a typical breakdown behavior, the RTO grown oxide on strained-Si/SiGe samples showed a quasi-or soft-breakdown with lower t bd value. It may be pointed out that quasi-breakdown may be a stronger reliability limiting factor for strained-Si/SiGe devices in the oxide thickness range studied

  16. Experimentally Studied Thermal Piston-head State of the Internal-Combustion Engine with a Thermal Layer Formed by Micro-Arc Oxidation Method

    Directory of Open Access Journals (Sweden)

    N. Yu. Dudareva

    2015-01-01

    Full Text Available The paper presents results of experimental study to show the efficiency of reducing thermal tension of internal combustion engine (ICE pistons through forming a thermal barrier coating on the piston-head. During the engine operation the piston is under the most thermal stress. High temperatures in the combustion chamber may lead to the piston-head burnout and destruction and engine failure.Micro-arc oxidation (MAO method was selected as the technology to create a thermal barrier coating. MAO technology allows us to form the ceramic coating with a thickness of 400μm on the surface of aluminum alloy, which have high heat resistance, and have good adhesion to the substrate even under thermal cycling stresses.Deliverables of MAO method used to protect pistons described in the scientific literature are insufficient, as they are either calculated or experimentally obtained at the special plants (units, which do not reproduce piston operation in a real engine. This work aims to fill this gap. The aim of the work is an experimental study of the thermal protective ability of MAO-layer formed on the piston-head with simulation of thermal processes of the real engine.The tests were performed on a specially designed and manufactured stand free of motor, which reproduces operation conditions maximum close to those of the real engine. The piston is heated by a fire source - gas burner with isobutene balloon, cooling is carried out by the water circulation system through the water-cooling jacket.Tests have been conducted to compare the thermal state of the regular engine piston without thermal protection and the piston with a heat layer formed on the piston-head by MAO method. The study findings show that the thermal protective MAO-layer with thickness of 100μm allows us to reduce thermal tension of piston on average by 8,5 %. Thus at high temperatures there is the most pronounced effect that is important for the uprated engines.The obtained findings can

  17. Evaluation of disintegration properties of orally rapidly disintegrating tablets using a novel disintegration tester.

    Science.gov (United States)

    Kondo, Keita; Niwa, Toshiyuki; Danjo, Kazumi

    2012-01-01

    This report describes a new disintegration tester that can determine not only the disintegration time of orally rapidly disintegrating tablets (ODT), but also the disintegration behavior and mechanism. Using the tester, the disintegration properties of the tablets prepared in a previous study were examined. The purpose of this study is to confirm the utility of the tester as an instrument for evaluating the disintegration properties of ODT and determine relations among time, behavior and mechanism of the disintegration. Results demonstrated that in vitro disintegration time in the tester is similar to that in the commercial disintegration tester for ODT and is highly correlated with oral disintegration time. Observations of disintegration process revealed that a difference in disintegration behavior between tablets compressed at 50-75 MPa and 100 MPa; the disintegration behavior of the tablets were designated immediate disintegrating type and gradual disintegrating type, respectively. The dynamic swelling profile and water absorption profile indicated that the disintegration mechanism of the tablets involved wicking action induced by swelling of the disintegrant; the disintegration time was closely related to the initial rates of swelling and water absorption. Furthermore, the mechanism of water absorption of tablets compressed at 50-75 MPa and 100 MPa shows anomalous diffusion and case-II transport, respectively. The shift in this mechanism is consistent with differences in disintegration time and behavior between the tablets. These findings suggest that information on disintegration properties obtained by our tester is useful for understanding of disintegration phenomena of ODT.

  18. Synthesis and structural, magnetic, thermal, and transport properties of several transition metal oxides and aresnides

    Energy Technology Data Exchange (ETDEWEB)

    Das, Supriyo [Iowa State Univ., Ames, IA (United States)

    2010-01-01

    Oxide compounds containing the transition metal vanadium (V) have attracted a lot of attention in the field of condensed matter physics owing to their exhibition of interesting properties including metal-insulator transitons, structural transitions, ferromagnetic and an- tiferromagnetic orderings, and heavy fermion behavior. Binary vanadium oxides VnO2n-1 where 2 ≤ n ≤ 9 have triclinic structures and exhibit metal-insulator and antiferromagnetic transitions.[1–6] The only exception is V7O13 which remains metallic down to 4 K.[7] The ternary vanadium oxide LiV2O4 has the normal spinel structure, is metallic, does not un- dergo magnetic ordering and exhibits heavy fermion behavior below 10 K.[8] CaV2O4 has an orthorhombic structure[9, 10] with the vanadium spins forming zigzag chains and has been suggested to be a model system to study the gapless chiral phase.[11, 12] These provide great motivation for further investigation of some known vanadium compounds as well as to ex- plore new vanadium compounds in search of new physics. This thesis consists, in part, of experimental studies involving sample preparation and magnetic, transport, thermal, and x- ray measurements on some strongly correlated eletron systems containing the transition metal vanadium. The compounds studied are LiV2O4, YV4O8, and YbV4O8. The recent discovery of superconductivity in RFeAsO1-xFx (R = La, Ce, Pr, Gd, Tb, Dy, Sm, and Nd), and AFe2As2 (A = Ba, Sr, Ca, and Eu) doped with K, Na, or Cs at the A site with relatively high Tc has sparked tremendous activities in the condensed matter physics community and a renewed interest in the area of superconductivity as occurred following the discovery of the layered cuprate high Tc superconductors in 1986. To discover more supercon- ductors

  19. Synthesis of metal-fluoride nanoparticles supported on thermally reduced graphite oxide

    Directory of Open Access Journals (Sweden)

    Alexa Schmitz

    2017-11-01

    Full Text Available Metal-fluoride nanoparticles, (MFx-NPs with M = Fe, Co, Pr, Eu, supported on different types of thermally reduced graphite oxide (TRGO were obtained by microwave-assisted thermal decomposition of transition-metal amidinates, (M{MeC[N(iPr]2}n or [M(AMDn] with M = Fe(II, Co(II, Pr(III, and tris(2,2,6,6-tetramethyl-3,5-heptanedionatoeuropium, Eu(dpm3, in the presence of TRGO in the ionic liquid (IL 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF4]. The crystalline phases of the metal fluorides synthesized in [BMIm][BF4] were identified by powder X-ray diffraction (PXRD to be MF2 for M = Fe, Co and MF3 for M = Eu, Pr. The diameters and size distributions of MFx@TRGO were from (6 ± 2 to (102 ± 41 nm. Energy-dispersive X-ray spectroscopy (EDX and X-ray photoelectron spectroscopy (XPS were used for further characterization of the MFx-NPs. Electrochemical investigations of the FeF2-NPs@TRGO as cathode material for lithium-ion batteries were evaluated by galvanostatic charge/discharge profiles. The results indicate that the FeF2-NPs@TRGO as cathode material can present a specific capacity of 500 mAh/g at a current density of 50 mA/g, including a significant interfacial charge storage contribution. The obtained nanomaterials show a good rate capacity as well (220 mAh/g and 130 mAh/g at a current density of 200 and 500 mA/g, respectively.

  20. Thermal aspects of mixed oxide fuel in application to supercritical water-cooled nuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    Grande, L.; Peiman, W.; Rodriguez-Prado, A.; Villamere, B.; Mikhael, S.; Allison, L.; Pioro, I., E-mail: lisa.grande@mycampus.uoit.ca, E-mail: igor.pioro@uoit.ca [Univ. of Ontario Inst. of Tech., Faculty of Energy Systems and Nuclear Science, Oshawa, Ontario (Canada)

    2010-07-01

    SuperCritical Water-cooled nuclear Reactors (SCWRs) are a renewed technology being developed as one of the Generation IV reactor concepts. This reactor type uses a light water coolant at temperatures and pressures above its critical point. These elevated operating conditions will improve Nuclear Power Plant (NPP) thermal efficiencies by 10 - 15% compared to those of current NPPs. Also, SCWRs will have the ability to utilize a direct cycle, thus decreasing NPP capital and operational costs. The SCWR core has 2 configurations: 1) Pressure Vessel (PV) -type enclosing a fuel assembly and 2) Pressure Tube (PT) -type consisting of individual pressurized channels containing fuel bundles. Canada and Russia are developing PT-type SCWRs. In particular, the Canadian SCWR reactor has an output of 1200 MW{sub el} and will operate at a pressure of 25 MPa with inlet and outlet fuel-channel temperatures of 350 and 625°C, respectively. These extreme operating conditions require alternative fuels and materials to be investigated. Current CANadian Deuterium Uranium (CANDU) nuclear reactor fuel-channel design is based on the use of uranium dioxide (UO{sub 2}) fuel; zirconium alloy sheath (clad) bundle, pressure and calandria tubes. Alternative fuels should be considered to supplement depleting world uranium reserves. This paper studies general thermal aspects of using Mixed OXide (MOX) fuel in an Inconel-600 sheath in a generic PT-type SCWR. The bulk fluid, sheath and fuel centerline temperatures along with the Heat Transfer Coefficient (HTC) profiles were calculated at uniform and non-uniform Axial Heat Flux Profiles (AHFPs). (author)

  1. Thermal stress management of a solid oxide fuel cell using neural network predictive control

    International Nuclear Information System (INIS)

    Hajimolana, S.A.; Tonekabonimoghadam, S.M.; Hussain, M.A.; Chakrabarti, M.H.; Jayakumar, N.S.; Hashim, M.A.

    2013-01-01

    In SOFC (solid oxide fuel cell) systems operating at high temperatures, temperature fluctuation induces a thermal stress in the electrodes and electrolyte ceramics; therefore, the cell temperature distribution is recommended to be kept as constant as possible. In the present work, a mathematical model based on first principles is presented to avert such temperature fluctuations. The fuel cell running on ammonia is divided into five subsystems and factors such as mass/energy/momentum transfer, diffusion through porous media, electrochemical reactions, and polarization losses inside the subsystems are presented. Dynamic cell-tube temperature responses of the cell to step changes in conditions of the feed streams is investigated. The results of simulation indicate that the transient response of the SOFC is mainly influenced by the temperature dynamics. It is also shown that the inlet stream temperatures are associated with the highest long term start-up time (467 s) among other parameters in terms of step changes. In contrast the step change in fuel velocity has the lowest influence on the start-up time (about 190 s from initial steady state to the new steady state) among other parameters. A NNPC (neural network predictive controller) is then implemented for thermal stress management by controlling the cell tube temperature to avoid performance degradation by manipulating the temperature of the inlet air stream. The regulatory performance of the NNPC is compared with a PI (proportional–integral) controller. The performance of the control system confirms that NNPC is a non-linear-model-based strategy which can assure less oscillating control responses with shorter settling times in comparison to the PI controller. - Highlights: • Effect of the operating parameters on the fuel cell temperature is analysed. • A neural network predictive controller (NNPC) is implemented. • The performance of NNPC is compared with the PI controller. • A detailed model is used for

  2. Carbon-Starvation Induces Cross-Resistance to Thermal, Acid, and Oxidative Stress in Serratia marcescens

    Science.gov (United States)

    Pittman, Joseph R.; Kline, La’Kesha C.; Kenyon, William J.

    2015-01-01

    The broad host-range pathogen Serratia marcescens survives in diverse host and non-host environments, often enduring conditions in which the concentration of essential nutrients is growth-limiting. In such environments, carbon and energy source starvation (carbon-starvation) is one of the most common forms of stress encountered by S. marcescens. Related members of the family Enterobacteriaceae are known to undergo substantial changes in gene expression and physiology in response to the specific stress of carbon-starvation, enabling non-spore-forming cells to survive periods of prolonged starvation and exposure to other forms of stress (i.e., starvation-induced cross-resistance). To determine if carbon-starvation also results in elevated levels of cross-resistance in S. marcescens, both log-phase and carbon-starved cultures, depleted of glucose before the onset of high cell-density stationary-phase, were grown in minimal media at either 30 °C or 37 °C and were then challenged for resistance to high temperature (50 °C), low pH (pH 2.8), and oxidative stress (15 mM H2O2). In general, carbon-starved cells exhibited a higher level of resistance to thermal stress, acid stress, and oxidative stress compared to log-phase cells. The extent of carbon-starvation-induced cross-resistance was dependent on incubation temperature and on the particular strain of S. marcescens. In addition, strain- and temperature-dependent variations in long-term starvation survival were also observed. The enhanced stress-resistance of starved S. marcescens cells could be an important factor in their survival and persistence in many non-host environments and within certain host microenvironments where the availability of carbon sources is suboptimal for growth. PMID:27682115

  3. Smouldering Combustion of Soil Organic Matter: Inverse Modelling of the Thermal and Oxidative Degradation Kinetics

    Science.gov (United States)

    Huang, Xinyan; Rein, Guillermo

    2013-04-01

    Smouldering combustion of soil organic matter (SOM) such as peatlands leads to the largest fires on Earth and posses a possible positive feedback mechanism to climate change. In this work, a kinetic model, including 3-step chemical reactions and 1-step water evaporation is proposed to describe drying, pyrolysis and oxidation behaviour of peat. Peat is chosen as the most important type of SOM susceptible to smoudering, and a Chinese boreal peat sample is selected from the literature. A lumped model of mass loss based on four Arrhenius-type reactions is developed to predict its thermal and oxidative degradation under a range of heating rates. A genetic algorithm is used to solve the inverse problem, and find a group of kinetic and stoichiometric parameters for this peat that provides the best match to the thermogravimetric (TG) data from literature. A multi-objective fitness function is defined using the measurements of both mass loss and mass-loss rate in inert and normal atmospheres under a range of heating rates. Piece-wise optimization is conducted to separate the low temperature drying (450 K). Modelling results shows the proposed 3-step chemistry is the unique simplest scheme to satisfy all given TG data of this particular peat type. Afterward, this kinetic model and its kinetic parameters are incorporated into a simple one-dimensional species model to study the relative position of each reaction inside a smoulder front. Computational results show that the species model agrees with experimental observations. This is the first time that the smouldering kinetics of SOM is explained and predicted, thus helping to understanding this important natural and widespread phenomenon.

  4. Carbon-Starvation Induces Cross-Resistance to Thermal, Acid, and Oxidative Stress in Serratia marcescens

    Directory of Open Access Journals (Sweden)

    Joseph R. Pittman

    2015-10-01

    Full Text Available The broad host-range pathogen Serratia marcescens survives in diverse host and non-host environments, often enduring conditions in which the concentration of essential nutrients is growth-limiting. In such environments, carbon and energy source starvation (carbon-starvation is one of the most common forms of stress encountered by S. marcescens. Related members of the family Enterobacteriaceae are known to undergo substantial changes in gene expression and physiology in response to the specific stress of carbon-starvation, enabling non-spore-forming cells to survive periods of prolonged starvation and exposure to other forms of stress (i.e., starvation-induced cross-resistance. To determine if carbon-starvation also results in elevated levels of cross-resistance in S. marcescens, both log-phase and carbon-starved cultures, depleted of glucose before the onset of high cell-density stationary-phase, were grown in minimal media at either 30 °C or 37 °C and were then challenged for resistance to high temperature (50 °C, low pH (pH 2.8, and oxidative stress (15 mM H2O2. In general, carbon-starved cells exhibited a higher level of resistance to thermal stress, acid stress, and oxidative stress compared to log-phase cells. The extent of carbon-starvation-induced cross-resistance was dependent on incubation temperature and on the particular strain of S. marcescens. In addition, strain- and temperature-dependent variations in long-term starvation survival were also observed. The enhanced stress-resistance of starved S. marcescens cells could be an important factor in their survival and persistence in many non-host environments and within certain host microenvironments where the availability of carbon sources is suboptimal for growth.

  5. Environmental degradation of oxidation resistant and thermal barrier coatings for fuel-flexible gas turbine applications

    Science.gov (United States)

    Mohan, Prabhakar

    The development of thermal barrier coatings (TBCs) has been undoubtedly the most critical advancement in materials technology for modern gas turbine engines. TBCs are widely used in gas turbine engines for both power-generation and propulsion applications. Metallic oxidation-resistant coatings (ORCs) are also widely employed as a stand-alone protective coating or bond coat for TBCs in many high-temperature applications. Among the widely studied durability issues in these high-temperature protective coatings, one critical challenge that received greater attention in recent years is their resistance to high-temperature degradation due to corrosive deposits arising from fuel impurities and CMAS (calcium-magnesium-alumino-silicate) sand deposits from air ingestion. The presence of vanadium, sulfur, phosphorus, sodium and calcium impurities in alternative fuels warrants a clear understanding of high-temperature materials degradation for the development of fuel-flexible gas turbine engines. Degradation due to CMAS is a critical problem for gas turbine components operating in a dust-laden environment. In this study, high-temperature degradation due to aggressive deposits such as V2O5, P2O 5, Na2SO4, NaVO3, CaSO4 and a laboratory-synthesized CMAS sand for free-standing air plasma sprayed (APS) yttria stabilized zirconia (YSZ), the topcoat of the TBC system, and APS CoNiCrAlY, the bond coat of the TBC system or a stand-alone ORC, is examined. Phase transformations and microstructural development were examined by using x-ray diffraction, scanning electron microscopy, and transmission electron microscopy. This study demonstrated that the V2O5 melt degrades the APS YSZ through the formation of ZrV2O7 and YVO 4 at temperatures below 747°C and above 747°C, respectively. Formation of YVO4 leads to the depletion of the Y2O 3 stabilizer and the deleterious transformation of the YSZ to the monoclinic ZrO2 phase. The investigation on the YSZ degradation by Na 2SO4 and a Na2SO4 + V2

  6. Effects of asphalt rejuvenator on thermal and mechanical properties on oxidized hot mixed asphalt pavements

    Science.gov (United States)

    Farace, Nicholas A.; Buttlar, William G.; Reis, Henrique

    2016-04-01

    The utilization of asphalt rejuvenator, and its effectiveness for restoring thermal and mechanical properties was investigated via Disk-shaped Compact Tension (DC(T)) and acoustic emission (AE) testing for determining mechanical properties and embrittlement temperatures of the mixtures. During the DC(T) testing the fracture energies and peak loads were used to measure the resistance of the rejuvenated asphalt to low temperature cracking. The AE testing monitored the acoustic emission activity while the specimens were cooled from room temperature to -40 °C to estimate the temperature at which thermal cracking began (i.e. the embrittlement temperature). First, a baseline response was obtained by obtaining the mechanical and thermal response of virgin HMA samples and HMA samples that had been exposed to oxidative aging for 36 hours at 135°C. The results showed the virgin samples had much higher peak loads and fracture energies than the 36 hours aged samples. Acoustic Emission showed similar results with the virgin samples having embrittlement temperatures 10 °C cooler than the 36 hours aged specimens. Then, overaged for 36 hours specimens were treated different amounts of rejuvenator (10%, 15%, and 20% by weight of binder content) and left to dwell for increased amount of time periods varying from one to eight weeks. It was observed that the AE results showed an improvement of embrittlement temperature with increasing with the dwell times. The 8 weeks specimens had cooler embrittlement temperatures than the virgin specimens. Finally, the low temperature effects on fracture energy and peak load of the rejuvenated asphalt was investigated. Rejuvenator was applied (10% by weight of binder) to specimens aged 36 hours at 135 °C, and the dwell time was varied from 1 to 4 weeks. The results showed that the peak loads were restored to levels of the virgin specimens, and the fracture energies improved to levels beyond that of the virgin specimens. The results also showed a

  7. Resistive switching of Cu/Cu2O junction fabricated using simple thermal oxidation at 423 K for memristor application

    Science.gov (United States)

    Ani, M. H.; Helmi, F.; Herman, S. H.; Noh, S.

    2018-01-01

    Recently, extensive researches have been done on memristor to replace current memory storage technologies. Study on active layer of memristor mostly involving n-type semiconductor oxide such as TiO2 and ZnO. This paper highlight a simple water vapour oxidation method at 423 K to form Cu/Cu2O electronic junction as a new type of memristor. Cu2O is a p-type semiconductor oxide, was used as the active layer of memristor. Cu/Cu2O/Au memristor was fabricated by thermal oxidation of copper foil, followed by sputtering of gold. Structural, morphological and memristive properties were characterized using XRD, FESEM, and current-voltage, I-V measurement respectively. Its memristivity was indentified by pinch hysteresis loop and measurement of high resistance state (HRS) and low resistance state (LRS) of the sample. The Cu/Cu2O/Au memristor demonstrates comparable performances to previous studies using other methods.

  8. Properties of ion implanted epitaxial CoSi2/Si(1 0 0) after rapid thermal oxidation

    International Nuclear Information System (INIS)

    Zhao, Q.T.; Kluth, P.; Xu, J.; Kappius, L.; Zastrow, U.; Wang, Z.L.; Mantl, S.

    2000-01-01

    Epitaxial CoSi 2 layers were grown on Si(1 0 0) using molecular beam allotaxy. Boron ion implantations and rapid thermal oxidation (RTO) were performed. During oxidation, SiO 2 formed on the surface of the CoSi 2 layers, and the silicides was pushed into the substrate. The diffusion of boron was slightly retarded during oxidation for the specimen with a 20 nm epitaxial CoSi 2 capping layer as compared to the specimen without CoSi 2 capping layer. The electrical measurements showed that the silicide has good Schottky contacts with the boron doped silicon layer after RTO. A nanometer silicide patterning process, based on local oxidation of silicide (LOCOSI) layer, was also investigated. It shows two back-to-back Schottky diodes between the two separated parts of the silicide

  9. Aging Depth Test of Rubber Blocks by Accelerated Thermal Oxidation Test

    International Nuclear Information System (INIS)

    Park, Junhee; Choun, Young-Sun; Kim, Min Kyu

    2015-01-01

    In this study, the accelerated thermal oxidation tests of rubber block were performed to investigate the aging depth of rubber bearing. From the tests, it was found the critical aging depth in rubber block. Also the property variation of rubber was investigated along the depth. The deterioration pattern from the aging depth tests was found from surface to inside and the critical aging depth was to be about 10 mm. The analytical model for rubber bearing with aging can be developed based on the relationship between the property variation and aging depth investigated from this study. The mechanical properties of rubber bearings were changed with time. Because the aging effect of rubber material was generally higher than that of other structure materials it is needed that the aging properties of seismically isolators should be evaluated to ensure the safety of seismically isolated nuclear power plants (NPPs) over the lifetime. NRC and ASCE required the tests of seismically isolators for investigating the aging properties. JNES also required the seismic response analysis for the seismically isolated NPPs when the properties of seismically isolators were extremely changed. If the aging properties of seismically isolators such as rubber bearings are evaluated by analysis the analytical model of seismically isolators should be developed considering aging effect of rubber material. From the previous research, it was reported that the behavior of aged rubber material mainly affected by temperature and oxidation. The material properties between surface and inside can be different by the oxidation of rubber. Therefore, the aging depth should be investigated for exactly evaluating the seismic behavior of aged rubber bearing. The aging depth of rubber baring was not influenced by the size of seismically isolators but environment condition. Therefore, the detail analysis considering aging depth was not required for NPPs with large seismically isolators. But the seismic response

  10. Thermal and combined thermal and radiolytic reactions involving nitrous oxide, hydrogen, nitrogen, and ammonia in contact with tank 241-SY-101 simulated waste

    International Nuclear Information System (INIS)

    Bryan, S.A.; Pederson, L.R.

    1996-02-01

    Work described in this report was conducted at Pacific Northwest National Laboratory (PNNL) for the Flammable Gas Safety Project, the purpose of which is to develop information needed to support Westinghouse Hanford Company (WHC) in their efforts to ensure the safe interim storage of wastes at the Hanford Site. Described in this report are the results of tests to evaluate the rates of thermal and combined thermal and radiolytic reactions involving flammable gases in the presence of Tank 241-SY-101 simulated waste. Flammable gases generated by the radiolysis of water and by the thermal and radiolytic decomposition of organic waste constituents may themselves participate in further reactions. Examples include the decomposition of nitrous oxide to yield nitrogen and oxygen, the reaction of nitrous oxide and hydrogen to produce nitrogen and water, and the reaction of nitrogen and hydrogen to produce ammonia. The composition of the gases trapped in bubbles in the wastes might therefore change continuously as a function of the time that the gas bubbles are retained

  11. BNFL's application of computer aided engineering to 'THORP' thermal oxide reprocessing plant

    International Nuclear Information System (INIS)

    Hall-Wilton, M.J.

    1990-01-01

    BNFL are currently constructing facilities at Sellafield, Cumbria to reprocess thermal oxide fuel for U.K., European and Japanese utilities. Faced with a 3.5bn pound capital program to provide new facilities at Sellafield, BNFL took the opportunity to embrace the new computer aided engineering technologies then emerging in 1981. To give some idea of the commitment made by BNFL to the above many millions of pounds has been invested in hardware, and more on software and people. The 'THORP' (Head End and Chemical Separation Plant) project represents 1.5bn pounds. The introduction of computer aided engineering has provided a clash free design with full assurance that all materials and components used are compatible. Planning in the design offices in conjunction with an experienced construction management team enables the sequence of piping installation to be determined long before the construction teams enter the work area. This planning aspect has been significantly improved by using EVS (Enhanced Visualisation System). The use of supercomputing graphics facilities is stimulating demands from areas of engineering who have previously not sought to use magnetic data from a variety of sources. The result is mainly due to the data being easily accessible to users who have very little computing experience. (N.K.)

  12. Basic properties of the mixed oxides obtained by thermal decomposition of hydrotalcites containing different metallic compositions

    Energy Technology Data Exchange (ETDEWEB)

    Valente, J.S.; Figueras, F.; Gravelle, M.; Kumbhar, P.; Lopez, J.; Besse, J.P.

    2000-01-25

    Carbonated layered double hydroxides (LDHs) containing Al, Fe, or Cr in a Mg(OH){sub 2} matrix or Al dissolved in hydroxides of Mg, Cu, Ni, Co, or Zn are used as precursors of basic catalysts. Decarbonation is studied by thermal analysis. The average basic strength, evaluated by the decarbonation temperature, is related to the partial charge of oxygen in the LDHs obtained from the Sanderson theory of electronegativity. The enthalpy of adsorption of CO{sub 2} on the resulting mixed oxides is measured by calorimetry. A homogeneous surface is generally observed for CO{sub 2} adsorption, with initial heats of adsorption close to those reported for MgO. The number of sites determined by this method is proportional to the rate constants for {beta}-isophorone isomerization, suggesting that both techniques measure surface properties. The layered structure in which OH{sup {minus}} is the compensating anion can be re-formed by hydration. This process does not appreciably change the adsorption of CO{sub 2}; thus, oxygens and hydroxyls show similar basic strengths in this case.

  13. Investigation of thermal conductivity and oxidation behaviour of reaction bonded aluminum nitride (RBAN) ceramics

    International Nuclear Information System (INIS)

    Salahi, E; Moztarzadeh, F.; Margoosian, V.; Heinrich, J. G.

    2003-01-01

    AlN samples have been produced by reaction bonding process using AlN and aluminum powders as starting materials. Different aluminum nitride and aluminum powders ratios were mixed in ethanol media, dried, isostatically and nitrided in (N 2 )atmosphere. Results showed that conversion of to AlN depends strongly on the amount of aluminum starting powder and decreased with increasing after a maximum at 25 Al wt %. Changing the particle size and morphology of the aluminum starting powder leads to change in the conversion ratio and microstructure of RBAN ceramics. Typical scanning electron micrographs of RBAN sample indicating primary and secondary aluminum nitride morphology and pore structure. The oxidation behavior of RABN samples showed the weight gain depends on the average particle size, morphology and amount of Al in starting mixture and pore structure. Samples have been manufactured with equi-axed morphology of Al starting powder have thermal conductivity higher than the samples have been manufactured with flake-like morphology. These differences were directly related to the different microstructure of RBAN samples

  14. Thermal, mechanical and dielectric properties of poly(vinyl alcohol)/graphene oxide composites

    Science.gov (United States)

    Rathod, Sunil G.; Bhajantri, R. F.; Ravindrachary, V.; Pujari, P. K.; Sheela, T.; Naik, Jagadish

    2014-04-01

    In this work the composite films of poly(vinyl alcohol) (PVA) doped with functionalized Graphene Oxide (GO) were prepared by solution casting method. The films were characterized using FT-IR, DSC, XRD, mechanical properties and dielectric studies at room temperature. FTIR spectra shows the formation of hydrogen bonds between hydroxyl groups of PVA and the hydroxy groups of GO. The DSC thermograms shows the addition of GO to PVA greatly improves the thermal stability of the composites. XRD patterns shows that the GO exfoliated and uniformly dispersed in PVA matrix. Mechanical properties are significantly improved in PVA/GO composites. The tensile strength increased from 8.2 to 13.7 MPa and the Young's modulus increased from 7.5 to 24.8 MPa for 5 wt% GO doped sample. Dielectric spectroscopy showed a highest dielectric constant for the 5 wt% GO doped PVA films. This work provides a potential design strategy on PVA/GO composite, which would lead to higher-performance, flexible dielectric materials, high charge-storage devices.

  15. Thermal sensitivity of carbon nanotube and graphene oxide containing responsive hydrogels

    Directory of Open Access Journals (Sweden)

    E. Manek

    2016-08-01

    Full Text Available Comparative investigations are reported on poly(N-isopropylacrylamide (PNIPA gels of various carbon nanotube (CNT and graphene oxide (GO contents synthesized under identical conditions. The kind and concentration of the incorporated carbon nanoparticles (CNPs influence the swelling and stress-strain behaviour of the composites. Practically independently of the filler content, incorporation of CNPs appreciably improves the fracture stress properties of the gels. The time constant and the swelling ratio of the shrinkage following an abrupt increase in temperature of the swelling medium from 20 to 50 °C can be adjusted by selecting both the type and the amount of nanoparticle loading. This offers a means of accurately controlling the deswelling kinetics of drug release with PNIPA systems, and could be employed in sensor applications where fast and excessive shrinkage are a significant drawback. Both CNTs and GO enhance the infrared sensitivity of the PNIPA gel, thus opening a route for the design of novel drug transport and actuator systems. It is proposed that the influence of the CNPs depends more on their surface reactivity during the gel synthesis rather than on their morphology. One of the important findings of this study is the existence of a thermally conducting network in the GO filled gels.

  16. Non-thermal hydrogen plasma processing effectively increases the antibacterial activity of graphene oxide

    Science.gov (United States)

    Ke, Zhigang; Ma, Yulong; Zhu, Zhongjie; Zhao, Hongwei; Wang, Qi; Huang, Qing

    2018-01-01

    Graphene-based materials (GMs) are promising antibacterial agents which provide an alternative route to treat pathogenic bacteria with resistance to conventional antibiotics. To further improve their antibacterial activity, many methods have been developed to functionalize the GMs with chemicals. However, the application of additional chemicals may pose potential risks to the environment and human being. Herein, a radio-frequency-driven inductively coupled non-thermal hydrogen plasma was used to treat and reduce graphene oxide (GO) without using any other chemicals, and we found that the plasma-reduced GO (prGO) is with significantly higher bactericidal activity against Escherichia coli. The mechanism of the increased antibacterial activity of prGO is due to that plasma processing breaks down the GO sheets into smaller layers with more rough surface defects, which can thus induce more destructive membrane damages to the bacteria. This work sets another good example, showing that plasma processing is a green and low-cost alternative for GM modification for biomedical applications.

  17. Effect of Thermally Reduced Graphene Oxide on Mechanical Properties of Woven Carbon Fiber/Epoxy Composite

    Directory of Open Access Journals (Sweden)

    Nitai Chandra Adak

    2018-02-01

    Full Text Available Thermally reduced graphene oxide (TRGO was incorporated as a reinforcing filler in the epoxy resin to investigate the effect on the mechanical properties of carbon fiber (CF/epoxy composites. At first, the epoxy matrix was modified by adding different wt % of TRGO from 0.05 to 0.4 wt % followed by the preparation of TRGO/CF/epoxy composites througha vacuum-assisted resin transfer molding process. The prepared TRGO was characterized by using Fourier transform infrared spectroscopy, Raman Spectroscopy and field emission scanning electron microscopy (FE-SEM techniques. It was observed that the wrinkled structure of synthesized TRGO may be helpful to interlock with the epoxy resin and CF.The inter-laminar shear strength, in-plane fracture toughness and impact strength increased by ~67%, 62% and 93% at 0.2 wt % of TRGO loading in the CF/epoxy composites as compared to the CF reinforced epoxy. The mechanical properties of the hybrid composites decreased beyond the 0.2 wt % of TRGO incorporation in the epoxy resin. The fracture surfaces of the hybrid composites were studied by FE-SEM image analysis to investigate the synergistic effect of TRGO in the CF/epoxy composite. This study suggested that TRGO could be used asgood nanofiller to resist the matrix and fiber fracture.

  18. Thulium oxide fuel characterization study: Part 2, Environmental behavior and mechanical, thermal and chemical stability enhancement

    International Nuclear Information System (INIS)

    Nelson, C.A.

    1970-12-01

    A study was performed of the correlation between fuel form stability and exposure environment of (temperature and atmosphere). 100% Tm 2 O 3 , 80% Tm 2 O 3 /20% Yb 2 O 3 and 100% Yb 2 O 3 wafers were subjected to air, dynamic vacuum and static vacuum at temperatures to 2000 0 C for times to 100 hours. Results showed the Tm 2 O 3 /Yb 2 O 3 cubic structure to be unaffected by elemental levels of iron, aluminum, magnesium and silicon and unaffected by the environmental conditions imposed on the wafers. A second task emphasized the optimization of the thermal, mechanical and chemical stability of Tm 2 O 3 fuel forms. Enhancement was sought through process variable optimization and the addition of metal oxides to Tm 2 O 3 . CaO, TiO 2 and Al 2 O 3 were added to form a grain boundary precipitate to control fines generation. The presence of 1% additive was inadequate to depress the melting point of Tm 2 O 3 or to change the cubic crystalline structure of Tm 2 O 3 /Yb 2 O 3 . Tm 2 O 3 /Yb 2 O 3 wafers containing CaO developed a grain boundary phase that improved the resistance to fines generation. The presence of Yb 2 O 3 did not appear to measurably influence behavior

  19. Influence of Diatomite and Mineral Powder on Thermal Oxidative Ageing Properties of Asphalt

    Directory of Open Access Journals (Sweden)

    Yongchun Cheng

    2015-01-01

    Full Text Available Ageing of asphalt affects the performances of asphalt pavement significantly. Therefore, effects of diatomite and mineral powder on ageing properties of asphalt were investigated systematically in order to improve the antiageing property of mixture. Thin film oven test (TFOT was used to conduct the short term ageing in laboratory. Softening points, penetrations, force ductility, low temperature creep properties, and viscosities of asphalt mastics were tested before and after TFOT, respectively. Results indicated that percent retained penetration (PRP increased with the increasing of fillers. Increment of softening point (ΔT, ductility retention rate (DRR, deformation energy ageing index (JAI, and viscosity ageing index (VAI of asphalt mastics nonlinearly decreased with the increasing of fillers. Ageing of asphalt was reduced by diatomite and mineral powder. And the antiageing effect of diatomite was better than that of mineral powder as a result of its porous structure. It is suggested that the mineral powder could be reasonably replaced by diatomite in order to reduce thermal oxidative ageing of asphalt mixture. The optimal content of diatomite 12.8% is also suggested for engineering.

  20. Modelling of thermal behaviour of iron oxide layers on boiler tubes

    Science.gov (United States)

    Angelo, J. D.; Bennecer, A.; Kaczmarczyk, S.; Picton, P.

    2016-05-01

    Slender boiler tubes are subject to localised swelling when they are expose to excessive heat. The latter is due to the formation of an oxide layer, which acts as an insulation barrier. This excessive heat can lead to microstructural changes in the material that would reduce the mechanical strength and would eventually lead to critical and catastrophic failure. Detecting such creep damage remains a formidable challenge for boiler operators. It involves a costly process of shutting down the plant, performing electromagnetic and ultrasonic non-destructive inspection, repairing or replacing damaged tubes and finally restarting the plant to resume its service. This research explores through a model developed using a finite element computer simulation platform the thermal behaviour of slender tubes under constant temperature exceeding 723 °K. Our simulation results demonstrate that hematite layers up to 15 μm thickness inside the tubes do not act as insulation. They clearly show the process of long term overheating on the outside of boiler tubes which in turn leads to initiation of flaws.

  1. Thermal cycling damage evolution of a thermal barrier coating and the influence of substrate creep, interface roughness and pre-oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Schweda, Mario; Beck, Tilmann; Singheiser, Lorenz [Forschungszentrum Juelich GmbH (DE). Inst. fuer Energie- und Klimaforschung (IEK), Werkstoffstruktur und Eigenschaften (IEK-2)

    2012-01-15

    The influence of roughness profile shape, roughness depth, bond coat creep strength and pre-oxidation on the thermal cycling damage evolution and lifetime of a plasma-sprayed ZrO{sub 2} thermal barrier coating system was investigated. A simplified model system was used where FeCrAlY substrates simulated the bond coat. Substrate creep was varied by using the oxide dispersoid strengthened alloy MA956 and the conventional material Fecralloy. Stochastic 3- and periodic 2-dimensional roughness profiles were produced by sand blasting and high speed turning. Damage evolution is significantly influenced by substrate creep with a trend to higher lifetimes for the fast creeping substrate. Pre-oxidation has no influence. Lifetimes of the periodically profiled samples are up to 100 times lower than these of stochastically profiled samples. In the case of periodically profiled samples, the highest lifetime was reached for the highest roughness depth combined with local undercuttings in the roughness profile. For stochastically profiled samples the influence of roughness depth could not be determined due to the wide lifetime scatter. (orig.)

  2. Thermal cyclic oxidation behavior of the developed compositionally gradient graphite material of SiC/C in air environment

    International Nuclear Information System (INIS)

    Nakano, Junichi; Fujii, Kimio; Shindo, Masami

    1993-08-01

    For the developed compositionally gradient graphite material composed of surface SiC coating layer, middle SiC/C layer and graphite matrix, the thermal cyclic oxidation test was performed together with two kinds of the SiC coated graphite materials in air environment. It was made clear that the developed material exhibited high performance under severe thermal cyclic condition independent of the morphology of middle SiC/C layers and had the longer time or the more cycle margins from crack initiation to failure for surface SiC coating layer compared with the SiC coated graphite materials. (author)

  3. Effect of thermal implying during ageing process of nanorods growth on the properties of zinc oxide nanorod arrays

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, A. S., E-mail: kyrin-samaxi@yahoo.com; Mamat, M. H., E-mail: mhmamat@salam.uitm.edu.my; Rusop, M., E-mail: rusop@salam.uitm.my [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); NANO-SciTech Centre (NST), Institute of Science (IOS), Universiti Teknologi MARA - UiTM, 40450 Shah Alam, Selangor (Malaysia); Malek, M. F., E-mail: firz-solarzelle@yahoo.com; Abdullah, M. A. R., E-mail: ameerridhwan89@gmail.com; Sin, M. D., E-mail: diyana0366@johor.uitm.edu.my [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia)

    2016-07-06

    Undoped and Sn-doped Zinc oxide (ZnO) nanostructures have been fabricated using a simple sol-gel immersion method at 95°C of growth temperature. Thermal sourced by hot plate stirrer was supplied to the solution during ageing process of nanorods growth. The results showed significant decrement in the quality of layer produced after the immersion process where the conductivity and porosity of the samples reduced significantly due to the thermal appliance. The structural properties of the samples have been characterized using field emission scanning electron microscopy (FESEM) electrical properties has been characterized using current voltage (I-V) measurement.

  4. Mechanical Reinforcement, Shapestabilization and Thermal Improvement of Phase-Change Energy Storage Materials Using Graphene Oxide Aerogel

    Science.gov (United States)

    Schuman, Yue Xu

    Paraffin is known as a good energy storage phase change material (PCM) because of its high energy storage capacity and low cost. However, the leakage of liquid paraffin beyond its melting point and its low thermal conductivity hinder applications of paraffin in energy storage systems. Recently, nanomaterials have been used to create PCM composites in order to enhance their thermal properties while shape stabilizing the PCMs. However, fundamental studies on the material structures and mechanical behavior of the thermally enhanced PCM composites are limited especially at the nanoscale. In this study, we developed a PCM composite using graphene oxide aerogel (GOxA) as the reinforcing 3D network. The GOxA functions thermally as a heat transfer path and mechanically as a nanofiller to reinforce the PCM matrix. We characterized the morphology, the crystal and molecular structures as well as the multiscale mechanical and thermal behavior of the GOxA-PCM composite to evaluate the role of GOxA in the PCM composite. The molecular and diffraction characterizations imply that the GOxA network may affect the paraffin's crystallization, potentially forming an interfacial phase at the surfaces of GOxA. Furthermore, the mechanical properties were studied using nanoindentation at the nano/microscale and a digital durometer at the macroscale from 25degree C to 80 degree C. The mechanical characterizations show that the GOxA-PCM composite is 3 7x harder than pure paraffin and maintains significant strength even above paraffin's melting point due to the support from the GoxA. Moreover, the composite is much less strain-rate sensitive than paraffin. The reinforcement via GOxA is much beyond the prediction by the rule of mixture, implying a strong GOxA-paraffin interfacial bonding. Finally, a thermal scanning microscopy (SThM) along with AFM was used to study the thermal properties at microscale. AFM and thermal images indicate that GOxA-PCM has a better thermal conductivity. The latent

  5. Thermal Effect on the Structural, Electrical, and Optical Properties of In-Line Sputtered Aluminum Doped Zinc Oxide Films Explored with Thermal Desorption Spectroscopy

    Directory of Open Access Journals (Sweden)

    Shang-Chou Chang

    2014-01-01

    Full Text Available This work investigates the thermal effect on the structural, electrical, and optical properties of aluminum doped zinc oxide (AZO films. The AZO films deposited at different temperatures were measured using a thermal desorption system to obtain their corresponding thermal desorption spectroscopy (TDS. In addition to obtaining information of thermal desorption, the measurement of TDS also has the effect of vacuum annealing on the AZO films. The results of measuring TDS imply part of the doped aluminum atoms do not stay at substituted zinc sites in AZO films. The (002 preferential direction of the AZO films in X-ray diffraction spectra shifts to a lower angle after measurement of TDS. The grain size grows and surface becomes denser for all AZO films after measurement of TDS. The carrier concentration, mobility, and average optical transmittance increase while the electrical resistivity decreases for AZO films after measurement of TDS. These results indicate that the AZO films deposited at 200°C are appropriate selections if the AZO films are applied in device fabrication of heat-produced process.

  6. Characterization and Utilization of Calcium Oxide (CaO) Thermally Decomposed from Fish Bones as a Catalyst in the Production of Biodiesel from Waste Cooking Oil

    OpenAIRE

    Aldes Lesbani; Sabat Okta Ceria Sitompul; Risfidian Mohadi; Nurlisa Hidayati

    2016-01-01

    Thermal decomposition of fish bones to obtain calcium oxide (CaO) was conducted at various temperatures of 400, 500, 800, 900, 1000, and 1100 °C. The calcium oxide was then characterized using X-ray diffractometer, FTIR spectrophotometer, and SEM analysis. The calcium oxide obtained from the decomposition at 1000 °C was then used as a catalyst in the production of biodiesel from waste cooking oil. Diffraction pattern of the calcium oxide produced from decomposition at 1000...

  7. Comparison of stabilization by Vitamin E and 2,6-di-tert-butylphenols during polyethylene radio-thermal-oxidation

    International Nuclear Information System (INIS)

    Richaud, Emmanuel

    2014-01-01

    This paper reports a compilation of data for PE+Vitamin E and 2,6-di-tert-butylphenols oxidation in radio-thermal ageing. Data unambiguously show that Vitamin E reacts with P · and POO · whereas 2,6-di-tert-butyl phenols only react with POO · . Kinetic parameters of the stabilization reactions for both kinds of antioxidants were tentatively extracted from phenol depletion curves, and discussed regarding the structure of the stabilizer. They were also used for completing an existing kinetic model used for predicting the stabilization by antioxidants. This one permits to compare the efficiency of stabilizer with dose rate or sample thickness. - Highlights: • Radio-thermal oxidation of PE+phenolic antioxidants. • Comparison of Vitamin E and 2,6-di-tert-butylphenols. • Kinetic modeling for predicting practical cases

  8. Removal of Iron Oxide Scale from Feed-water in Thermal Power Plant by Using Magnetic Separation

    Science.gov (United States)

    Nakanishi, Motohiro; Shibatani, Saori; Mishima, Fumihito; Akiyama, Yoko; Nishijima, Shigehiro

    2017-09-01

    One of the factors of deterioration in thermal power generation efficiency is adhesion of the scale to inner wall in feed-water system. Though thermal power plants have employed All Volatile Treatment (AVT) or Oxygen Treatment (OT) to prevent scale formation, these treatments cannot prevent it completely. In order to remove iron oxide scale, we proposed magnetic separation system using solenoidal superconducting magnet. Magnetic separation efficiency is influenced by component and morphology of scale which changes their property depending on the type of water treatment and temperature. In this study, we estimated component and morphology of iron oxide scale at each equipment in the feed-water system by analyzing simulated scale generated in the pressure vessel at 320 K to 550 K. Based on the results, we considered installation sites of the magnetic separation system.

  9. The reliability of the newly developed bending tester for the measurement of flexural rigidity of textile materials

    Science.gov (United States)

    Haji Musa, A. Binti; Malengier, B.; Van Langenhove, L.; Stevens, C.

    2017-10-01

    A new automated bending tester was developed in Ghent University, Belgium to reduce the human interference in the bending measurement. This paper reports the investigations made on the tester in order to confirm the reliability of its measurement. For that, 11 types of fabrics with different construction parameters were tested for their bending length and flexural rigidity using the new bending tester and the results were compared with that of the standard or manual bending tester, which were conducted in accordance with BS 3356:1990 standard method. Statistical analysis confirms that both measurements are strongly correlated with Pearson’s R≥ 0.90 for all the measurements made. It means that the results from the new automated tester show good correlations with the standard measurement. Nevertheless, this prototype version of the new tester still needs to be adjusted to optimise the functionality of it and further investigations should be done to justify the robustness of the results.

  10. Fabrication of ammonium perchlorate/copper-chromium oxides core-shell nanocomposites for catalytic thermal decomposition of ammonium perchlorate

    Energy Technology Data Exchange (ETDEWEB)

    Eslami, Abbas, E-mail: eslami@umz.ac.ir [Department of Inorganic Chemistry, Faculty of Chemistry, University of Mazandaran, P.O.Box 47416-95447, Babolsar (Iran, Islamic Republic of); Juibari, Nafise Modanlou [Department of Inorganic Chemistry, Faculty of Chemistry, University of Mazandaran, P.O.Box 47416-95447, Babolsar (Iran, Islamic Republic of); Hosseini, Seyed Ghorban [Department of Chemistry, Malek Ashtar University of Technology, P.O. Box 16765-3454, Tehran (Iran, Islamic Republic of)

    2016-09-15

    The ammonium perchlorate/Cu(II)-Cr(III)-oxides(AP/Cu-Cr-O) core-shell nanocomposites were in-situ prepared by deposition of copper and chromium oxides on suspended ammonium perchlorate particles in ethyl acetate as solvent. The results of differential scanning calorimetery (DSC) and thermal gravimetric analysis (TGA) experiments showed that the nanocomposites have excellent catalytic effect on the thermal decomposition of AP, so that the released heat increases up to about 3-fold over initial values, changing from 450 J/g for pure AP to 1510 J/g for most appropriate mixture. For better comparison, single metal oxide/AP core-shell nanocomposite have also been prepared and the results showed that they have less catalytic effect respect to mixed metal oxides system. Scanning electron microscopy (SEM) results revealed homogenous deposition of nanoparticles on the surface of AP and fabrication of core-shell structures. The kinetic parameters of thermal decomposition of both pure AP and AP/Cu-Cr-O samples have been calculated by Kissinger method and the results showed that the values of pre-exponential factor and activation energy are higher for AP/Cu-Cr-O nanocomposite. The better catalytic effect of Cu-Cr-O nanocomposites is probably attributed to the synergistic effect between Cu{sup 2+} and Cr{sup 3+} in the nanocomposites, smaller particle size and more crystal defect. - Highlights: • The Cu-Cr-O nanoparticles were synthesized by chemical liquid deposition method. • Then, the AP/Cu-Cr-O core-shell nanocomposites were prepared. • The core-shell samples showed high catalytic activity for AP decomposition. • Thermal decomposition of samples occurs at lower temperature range.

  11. Nanocomposites of recycled polycarbonate and nano-zinc oxide (rPC/nZnO): effect of gamma radiation and nano oxide content on the thermal properties

    International Nuclear Information System (INIS)

    Carvalho, A.L.F.; Mendes, L.C.; Cestari, S.P.

    2014-01-01

    In order to promote the barrier action to the ultraviolet radiation and increase of mechanical characteristics, nanocomposites of recycled polycarbonate (rPC) and nano-zinc oxide (nZnO) containing 1, 2 and 3 % (wt/wt) of nano oxide were prepared. Since for obtaining nanocomposites and irradiating polymers are promising tools and attractive for improving the material performance, the effects of nano-zinc oxide and gamma radiation, at doses ranged from 10 to 50 kGy, were evaluated in terms of thermal characteristics of the rPC. The rPC/nZnO nanocomposites were characterized by thermogravimetric analysis (TGA) and differential explanatory calorimetry (DSC). There was a progressive decrease of the T_g as function of gamma dosage and nano-zinc oxide content. Initially, the Tonset and Tmax decayed as function of gamma dosage but a recovery was observed. The amount of nano-zinc oxide induced a decreasing of T_o_n_s_e_t and T_m_a_x. (author)

  12. Advanced Oxide Material Systems for 1650 Deg. C Thermal/Environmental Barrier Coating Applications

    National Research Council Canada - National Science Library

    Zhu, Dongming; Fox, Dennis S; Bansal, Narottam P; Miller, Robert A

    2004-01-01

    ... systems under engine high-heat-flux and severe thermal cycling conditions. In this report, the thermal conductivity and water vapor stability of selected candidate hafnia-, pyrochlore-, and magnetoplumbite-based TEBC materials are evaluated...

  13. Optimization of NO oxidation by H2O2 thermal decomposition at moderate temperatures.

    Science.gov (United States)

    Zhao, Hai-Qian; Wang, Zhong-Hua; Gao, Xing-Cun; Liu, Cheng-Hao; Qi, Han-Bing

    2018-01-01

    H2O2 was adopted to oxidize NO in simulated flue gas at 100-500°C. The effects of the H2O2 evaporation conditions, gas temperature, initial NO concentration, H2O2 concentration, and H2O2:NO molar ratio on the oxidation efficiency of NO were investigated. The reason for the narrow NO oxidation temperature range near 500°C was determined. The NO oxidation products were analyzed. The removal of NOx using NaOH solution at a moderate oxidation ratio was studied. It was proven that rapid evaporation of the H2O2 solution was critical to increase the NO oxidation efficiency and broaden the oxidation temperature range. the NO oxidation efficiency was above 50% at 300-500°C by contacting the outlet of the syringe needle and the stainless-steel gas pipe together to spread H2O2 solution into a thin film on the surface of the stainless-steel gas pipe, which greatly accelerated the evaporation of H2O2. The NO oxidation efficiency and the NO oxidation rate increased with increasing initial NO concentration. This method was more effective for the oxidation of NO at high concentrations. H2O2 solution with a concentration higher than 15% was more efficient in oxidizing NO. High temperatures decreased the influence of the H2O2 concentration on the NO oxidation efficiency. The oxidation efficiency of NO increased with an increase in the H2O2:NO molar ratio, but the ratio of H2O2 to oxidized NO decreased. Over 80% of the NO oxidation product was NO2, which indicated that the oxidation ratio of NO did not need to be very high. An 86.7% NO removal efficiency was obtained at an oxidation ratio of only 53.8% when combined with alkali absorption.

  14. Effect of thermally reduced graphene oxide on dynamic mechanical properties of carbon fiber/epoxy composite

    Science.gov (United States)

    Adak, Nitai Chandra; Chhetri, Suman; Murmu, Naresh Chandra; Samanta, Pranab; Kuila, Tapas

    2018-03-01

    The Carbon fiber (CF)/epoxy composites are being used in the automotive and aerospace industries owing to their high specific mechanical strength to weight ratio compared to the other conventional metal and alloys. However, the low interfacial adhesion between fiber and polymer matrix results the inter-laminar fracture of the composites. Effects of different carbonaceous nanomaterials i.e., carbon nanotubes (CNT), graphene nanosheets (GNPs), graphene oxide (GO) etc. on the static mechanical properties of the composites were investigated in detail. Only a few works focused on the improvement of the dynamic mechanical of the CF/epoxy composites. Herein, the effect of thermally reduced grapheme oxide (TRGO) on the dynamic mechanical properties of the CF/epoxy composites was investigated. At first, GO was synthesized using modified Hummers method and then reduced the synthesized GO inside a vacuum oven at 800 °C for 5 min. The prepared TRGO was dispersed in the epoxy resin to modify the epoxy matrix. Then, a number of TRGO/CF/epoxy laminates were manufactured incorporating different wt% of TRGO by vacuum assisted resin transfer molding (VARTM) technique. The developed laminates were cured at room temperature for 24 h and then post cured at 120 °C for 2 h. The dynamic mechanical analyzer (DMA 8000 Perkin Elmer) was used to examine the dynamic mechanical properties of the TRGO/CF/epoxy composites according to ASTM D7028. The dimension of the specimen was 44×10×2.4 mm3 for the DMA test. This test was carried out under flexural loading mode (duel cantilever) at a frequency of 1 Hz and amplitude of 50 μm. The temperature was ramped from 30 to 200 °C with a heating rate of 5 °C min-1. The dynamic mechanical analysis of the 0.2 wt% TRGO incorporated CF/epoxy composites showed ~ 96% enhancement in storage modulus and ~ 12 °C increments in glass transition temperature (Tg) compared to the base CF/epoxy composites. The fiber-matrix interaction was studied by Cole

  15. Effect of ultrathin GeOx interfacial layer formed by thermal oxidation on Al2O3 capped Ge

    International Nuclear Information System (INIS)

    Han Le; Zhang Xiong; Wang Sheng-Kai; Xue Bai-Qing; Liu Hong-Gang; Wu Wang-Ran; Zhao Yi

    2014-01-01

    We propose a modified thermal oxidation method in which an Al 2 O 3 capping layer is used as an oxygen blocking layer (OBL) to form an ultrathin GeO x interfacial layer, and obtain a superior Al 2 O 3 /GeO x /Ge gate stack. The GeO x interfacial layer is formed in oxidation reaction by oxygen passing through the Al 2 O 3 OBL, in which the Al 2 O 3 layer could restrain the oxygen diffusion and suppress the GeO desorption during thermal treatment. The thickness of the GeO x interfacial layer would dramatically decrease as the thickness of Al 2 O 3 OBL increases, which is beneficial to achieving an ultrathin GeO x interfacial layer to satisfy the demand for small equivalent oxide thickness (EOT). In addition, the thickness of the GeO x interfacial layer has little influence on the passivation effect of the Al 2 O 3 /Ge interface. Ge (100) p-channel metal–oxide–semiconductor field-effect transistors (pMOSFETs) using the Al 2 O 3 /GeO x /Ge gate stacks exhibit excellent electrical characteristics; that is, a drain current on-off (I on /I off ) ratio of above 1×10 4 , a subthreshold slope of ∼ 120 mV/dec, and a peak hole mobility of 265 cm 2 /V·s are achieved. (condensed matter: structural, mechanical, and thermal properties)

  16. A circulating loop tester for liquid alloyed metal of lead-bismuth

    International Nuclear Information System (INIS)

    Kitano, Teruaki; Ono, Mikinori; Kamata, Kinya

    2002-01-01

    Mitsui Engineering and Shipbuilding Co., Ltd. (MES) had focused to merits of this lead-bismuth alloy, to actively carry out many works on this field such as an experience of development of heat exchanger at industrial level of intercourse with IPPE (Institute of Physics and Power Engineering) in Russia with an experience of using results for 80 years on coolant for nuclear reactor. Before about 20 years, MES developed a heat exchanger for installation at a lead-zinc separation process in a refinery in Japan under cooperation of the Mitsui Metal and Mine Co., Ltd., to deliver it for a power generation system at the Hachinohe refinery. As the heat exchanger aims at control of cooling in the separation process, it also contributes to power generation of about 4,300 kW, and now it continues to separate and contribute to self-power generation in the refinery. The heat exchanger is filled with the liquid alloyed metal of lead-bismuth for an intermediate thermal medium in its casing. The metal has some merits such as inactivity to air and water, high boiling point (1,700 centigrade), almost no volume change at its coagulation, and its minus reactivity coefficient. However, the metal has some problems to be solved, such as its steel corrosion, its purification, and control technology. To grow up lead-bismuth technology to a nuclear energy technology in Japan, the lead-bismuth circulating loop tester was produced on May, 2001, to establish application technology on this system to nuclear energy technology in Japan. (G.K.)

  17. Numerical simulation of displacement instabilities of surface grooves on an alumina forming alloy during thermal cycling oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Feng Xun; Kang, Ki Ju [Chonnam National University, Gwangju (Korea, Republic of); Ding, Jun [Chongqing University of Technology, Chongqing (China)

    2009-08-15

    Displacement instability of the thermally grown oxide (TGO) is a fundamental source of failure in thermal barrier systems. In this work, a finite element analysis has been performed to analyze the displacement instability occurring at a heat resistant metal with superficial TGO subjected to thermal cycling. Lateral and in-plane growth of the TGO which happens during high temperature is simulated by means of material property change from the substrate metal to the TGO. Most of the material properties including the TGO growth are based on the results experimentally obtained in-house. Results of the finite element analyses agree well with the experimental observation, which proves the accuracy and validity of this simulation. The technique will be useful for future work on more complicated phenomena such as deformation under thermo-mechanical cycling

  18. High temperature oxidation behavior of hafnium modified NiAl bond coat in EB-PVD thermal barrier coating system

    Energy Technology Data Exchange (ETDEWEB)

    Guo Hongbo; Sun Lidong; Li Hefei [Department of Material Science and Engineering, Beijing University of Aeronautics and Astronautics, No.37 Xueyuan Road, Beijing 100083 (China); Gong Shengkai [Department of Material Science and Engineering, Beijing University of Aeronautics and Astronautics, No.37 Xueyuan Road, Beijing 100083 (China)], E-mail: gongsk@buaa.edu.cn

    2008-06-30

    NiAl coatings doped with 0.5 at.% and 1.5 at.% Hf were produced by co-evaporation of NiAl and Hf ingots by electron beam physical vapor deposition (EB-PVD), respectively. The addition of 0.5 at.% Hf significantly improved the cyclic oxidation resistance of the NiAl coating. The TGO layer in the 1.5 at.% Hf doped NiAl coating is straight; while that in the 0.5 at.% Hf doped coating became undulated after thermal cycling. The doped NiAl thermal barrier coatings (TBCs) revealed improved thermal cycling lifetimes at 1423 K, compared to the undoped TBC. Failure of the 0.5 at.% Hf doped TBC occurred by cracking at the interface between YSZ topcoat and bond coat, while the 1.5 at.% Hf doped TBC cracked at the interface between bond coat and substrate.

  19. Effect of thermal annealing on the properties of transparent conductive In–Ga–Zn oxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ling [Key Laboratory of Physical Electronics and Devices of the Ministry of Education, Xi' an Jiaotong University, Xi' an 710049, China and School of Information Science and Engineering, Shandong University, Jinan 250100 (China); Fan, Lina; Li, Yanhuai; Song, Zhongxiao; Ma, Fei, E-mail: mafei@mail.xjtu.edu.cn, E-mail: chlliu@mail.xjtu.edu.cn [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Liu, Chunliang, E-mail: mafei@mail.xjtu.edu.cn, E-mail: chlliu@mail.xjtu.edu.cn [Key Laboratory of Physical Electronics and Devices of the Ministry of Education, Xi' an Jiaotong University, Xi' an 710049 (China)

    2014-03-15

    Amorphous In–Ga–Zn oxide (IGZO) thin films were prepared using radio frequency magnetron sputtering at room temperature. Upon thermal annealing at temperatures even up to 500 °C, the amorphous characteristics were still maintained, but the electronic properties could be considerably enhanced. This could be ascribed to the increased optical band gap and the increased oxygen vacancies, as corroborated by the microstructure characterizations. In addition, the surface became smoother upon thermal annealing, guaranteeing good interface contact between electrode and a-IGZO. The optical transmittance at 400–800 nm exceeded 90% for all samples. All in all, thermal annealing at appropriate temperatures is expected to improve the performances of relevant a-IGZO thin film transistors.

  20. Enhanced thermal and mechanical properties of epoxy composites by mixing thermotropic liquid crystalline epoxy grafted graphene oxide

    Directory of Open Access Journals (Sweden)

    B. Qi

    2014-07-01

    Full Text Available Graphene oxide (GO sheets were chemically grafted with thermotropic liquid crystalline epoxy (TLCP. Then we fabricated composites using TLCP-g-GO as reinforcing filler. The mechanical properties and thermal properties of composites were systematically investigated. It is found that the thermal and mechanical properties of the composites are enhanced effectively by the addition of fillers. For instance, the composites containing 1.0 wt% of TLCP-g-GO present impact strength of 51.43 kJ/m2, the tensile strength of composites increase from 55.43 to 80.85 MPa, the flexural modulus of the composites increase by more than 48%. Furthermore, the incorporation of fillers is effective to improve the glass transition temperature and thermal stability of the composites. Therefore, the presence of the TLCP-g-GO in the epoxy matrix could make epoxy not only stronger but also tougher.

  1. Strength and thermal stability of Cu-Al2O3 composite obtained by internal oxidation

    Directory of Open Access Journals (Sweden)

    Jovanovic, M. T.

    2010-12-01

    Full Text Available The objective of the work is to study the effects of the high-energy milling on strengthening, thermal stability and electrical conductivity of Cu-Al2O3 composite. The prealloyed copper powders, atomized in inert gas and containing 3 wt. % Al, were milled up to 20 h in the planetary ball mill to oxidize in situ aluminium with oxygen from the air. Composite compacts were obtained by hot-pressing in an argon atmosphere at 800 °C for 3 h under the pressure of 35MPa. The microstructural characterization was performed by the optical microscope, scanning electron microscope (SEM, transmission electron microscope (TEM and X-ray diffraction analysis (XRD. The microhardness, electrical conductivity and density measurements were also carried out. The effect of internal oxidation and high-energy milling on strengthening of Cu-Al2O3 composite was significant, The increase of the microhardness of composite compacts (292 HV is almost threefold comparing to compacts processed from the as-received Cu-3 wt. % Al powder (102 HV. The grain size of Cu-Al2O3 compacts processed from 5 and 20 h-milled powders was 75 and 45 nm, respectively. The small increase in the grain size and the small microhardness drop indicate the high thermal stability of Cu-Al2O3 composite during high-temperature exposure at 800 °C.El objetivo del trabajo es el estudio de los efectos de la pulverización con altas energías sobre la resistencia, estabilidad térmica y conductividad eléctrica del compuesto Cu-Al2O3. El polvo pre-aleado de cobre, obtenido a través de la atomización con gas inerte y con un contenido de 3wt. % Al, se molió durante 20 h en el molino planetario de bolas dando lugar a la oxidación in situ del aluminio con el oxígeno del aire. El compuesto compactado se ha obtenido mediante prensado en caliente en atmósfera de argón a 800 °C durante 3 h y a una presión de 35MPa. La caracterización microestructural se hizo a través de microscopia óptica, microscopia

  2. Best estimate probabilistic safety assessment results for the Westinghouse Advanced Loop Tester (WALT)

    International Nuclear Information System (INIS)

    Wang, Guoqiang; Xu, Yiban; Oelrich, Robert L. Jr.; Byers, William A.; Young, Michael Y.; Karoutas, Zeses E.

    2011-01-01

    The nuclear industry uses the probabilistic safety assessment (PSA) technique to improve safety decision making and operation. The methodology evaluates the system reliability, which is defined as the probability of system success, and the postulated accident/problematic scenarios of systems for the nuclear power plants or other facilities. The best estimate probabilistic safety assessment (BE-PSA) method of evaluating system reliability and postulated problematic scenarios will produce more detailed results of interest, such as best estimated reliability analysis and detailed thermal hydraulic calculations using a sub-channel or Computational Fluid Dynamics (CFD) code. The methodology is typically applied to reactors, but can also be applied to any system such as a test facility. In this paper, a BE-PSA method is introduced and used for evaluating the Westinghouse Advanced Loop Tester (WALT). The WALT test loop at the George Westinghouse Science and Technology Center (STC), which was completed in October 2005, is designed to be utilized to model the top grid span of a hot rod in a fuel assembly under the Pressurizer Water Reactor (PWR) normal operating conditions. In order to safely and successfully operate the WALT test loop and correctly use the WALT experimental data, it is beneficial to perform a probabilistic safety assessment and analyze the thermal hydraulic results for the WALT loop in detail. Since October 2005, a number of test runs have been performed on the WALT test facility designed and fabricated by Westinghouse Electric Company LLC. This paper briefly describes the BE-PSA method and performs BE-PSA for the WALT loop. Event trees linked with fault trees embedding thermal hydraulic analysis models, such as sub-channel and/or CFD models, were utilized in the analyses. Consequently, some selected useful experimental data and analysis results are presented for future guidance on WALT and/or other similar test facilities. For example, finding and

  3. Aerial and liquid effluent treatment in BNFL's Thermal Oxide Reprocessing Plant (THORP)

    International Nuclear Information System (INIS)

    Hudson, P.I.; Buckley, C.P.

    1996-01-01

    British Nuclear Fuels plc (BNFL) completed construction of its Thermal Oxide Reprocessing Plant (THORP) at Sellafield in 1992, at a cost of pound 1,850M. After Government and Regulatory approval, active commissioning was initiated in January 1994. Since then, the whole of the plant has been progressively commissioned and moved towards full operational status. From the outset, the need to protect the workforce, the public and the environment in general from the plant's discharges was clearly recognised. The design intent was to limit radiation exposure of members of the general public to 'As Low as Reasonably Practicable' (ALARP). Furthermore no member of the most highly exposed (critical) group should receive an annual dose exceeding 50 microsieverts from either the aerial or marine discharge routes. This paper describes how the design intent has been met, concentrating mainly on aerial discharges. It describes the sub-division of the plant's ventilation system into a number of separate systems, according to the volume and source of the arising and the complexity of the treatment process. The dissolver off-gas, central off-gas, cell and building ventilation systems are described, together with the development programme which was undertaken to address the more demanding aspects of the performance specification. This ranged from small-scale experiments with irradiated fuel to inactive pilot plant trials and full-scale plant measurements. In addition wind tunnel tests were employed to assist dispersion modelling of the gases as they are discharged from the THORP stack. All the resulting information was then used, with the aid of mathematical models, in the design of an off-gas treatment system which could achieve the overall goal. (J.P.N.)

  4. Growth of High-Density Zinc Oxide Nanorods on Porous Silicon by Thermal Evaporation

    Directory of Open Access Journals (Sweden)

    Nurul Izni Rusli

    2012-12-01

    Full Text Available The formation of high-density zinc oxide (ZnO nanorods on porous silicon (PS substrates at growth temperatures of 600–1000 °C by a simple thermal evaporation of zinc (Zn powder in the presence of oxygen (O2 gas was systematically investigated. The high-density growth of ZnO nanorods with (0002 orientation over a large area was attributed to the rough surface of PS, which provides appropriate planes to promote deposition of Zn or ZnOx seeds as nucleation sites for the subsequent growth of ZnO nanorods. The geometrical morphologies of ZnO nanorods are determined by the ZnOx seed structures, i.e., cluster or layer structures. The flower-like hexagonal-faceted ZnO nanorods grown at 600 °C seem to be generated from the sparsely distributed ZnOx nanoclusters. Vertically aligned hexagonal-faceted ZnO nanorods grown at 800 °C may be inferred from the formation of dense arrays of ZnOx clusters. The formation of disordered ZnO nanorods formed at 1000 °C may due to the formation of a ZnOx seed layer. The growth mechanism involved has been described by a combination of self-catalyzed vapor-liquid-solid (VLS and vapor-solid (VS mechanism. The results suggest that for a more precise study on the growth of ZnO nanostructures involving the introduction of seeds, the initial seed structures must be taken into account given their significant effects.

  5. Oxidation effect on steel corrosion and thermal loads during corium melt in-vessel retention

    Energy Technology Data Exchange (ETDEWEB)

    Granovsky, V.S.; Khabensky, V.B.; Krushinov, E.V.; Vitol, S.A.; Sulatsky, A.A.; Almjashev, V.I. [Alexandrov Scientific-Research Technology Institute (NITI), Sosnovy Bor (Russian Federation); Bechta, S.V. [KTH, Stockholm (Sweden); Gusarov, V.V. [SPb State Technology University (SPbGTU), St. Petersburg (Russian Federation); Barrachin, M. [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), St Paul lez Durance (France); Bottomley, P.D., E-mail: paul.bottomley@ec.europa.eu [EC-Joint Research Centre, Institute for Transuranium Elements (ITU), Karlsruhe (Germany); Fischer, M. [AREVA GmbH, Erlangen (Germany); Piluso, P. [Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), Cadarache, St Paul lez Durance (France)

    2014-10-15

    Highlights: • The METCOR facility simulates vessel steel corrosion in contact with corium. • Steel corrosion rates in UO{sub 2+x}–ZrO{sub 2}–FeO{sub y} coria accelerate above 1050 K. • However corrosion rates can also be limited by melt O{sub 2} supply. • The impact of this on in-vessel retention (IVR) strategy is discussed. - Abstract: During a severe accident with core meltdown, the in-vessel molten core retention is challenged by the vessel steel ablation due to thermal and physicochemical interaction of melt with steel. In accidents with oxidizing atmosphere above the melt surface, a low melting point UO{sub 2+x}–ZrO{sub 2}–FeO{sub y} corium pool can form. In this case ablation of the RPV steel interacting with the molten corium is a corrosion process. Experiments carried out within the International Scientific and Technology Center's (ISTC) METCOR Project have shown that the corrosion rate can vary and depends on both surface temperature of the RPV steel and oxygen potential of the melt. If the oxygen potential is low, the corrosion rate is controlled by the solid phase diffusion of Fe ions in the corrosion layer. At high oxygen potential and steel surface layer temperature of 1050 °C and higher, the corrosion rate intensifies because of corrosion layer liquefaction and liquid phase diffusion of Fe ions. The paper analyzes conditions under which corrosion intensification occurs and can impact on in-vessel melt retention (IVR)

  6. A comparison of damage profiling of automated tap testers on aircraft CFRP panel

    Science.gov (United States)

    Mohd Aris, K. D.; Shariff, M. F.; Abd Latif, B. R.; Mohd Haris, M. Y.; Baidzawi, I. J.

    2017-12-01

    The use of composite materials nevertheless is getting more prominent. The combination of reinforcing fibers and matrices will produce the desired strength orientation, tailorability and not to mention the complex shape that is hard to form on metallic structure. The weight percentage of composite materials used in aerospace, civil, marine etc. has increased tremendously. Since composite are stacked together, the possibility of delamination and/disbond defects are highly present either in the monolithic or sandwich structures. Tap test is the cheapest form of nondestructive test to identify the presence of this damage. However, its inconsistency and wide area of coverage can reduce its effectivity since it is carried out manually. The indigenous automated tap tester known as KETOK was used to detect the damage due to trapped voids and air pockets. The mechanism of detection is through controlling the tapping on the surface automatically at a constant rate. Another manual tap tester RD-3 from Wichitech Industries Inc. was used as reference. The acquired data was translated into damage profiling and both results were compared. The results have shown that the indigenous automated tester can profile the damage better when compared with the existing tap tester. As a conclusion, the indigenous automated tap tester has a potential to be used as an IN-SITU damage detection tool to detect delamination and disbond damage on composite panel. However, more conclusive tests need to be done in order to make the unit available to conventional users.

  7. HIV impact on women: gender difference among late testers and advanced HIV infection

    Science.gov (United States)

    Sukmawati, N. M. D. D.; Merati, T. P.; Somia, A.; Utama, S.; Gayatri, Y.

    2018-03-01

    This study reported the effect of gender difference on HIV seropositive late testers or advanced infection. A retrospective cohort study of newly diagnosed HIV seropositive based on adatabase in the main referral hospital in Denpasar, Bali, Indonesia from 2004 – 2016. Women and man were categorized as late testers (CD4 ≤ 200 cells/uL and/or AIDS diagnosis ≤ 12 months from first HIV test date). Non-late testers (CD4 > 200 cells/uL and/or no AIDS diagnosis during study period or diagnosis of AIDS >12 months from HIV diagnosis), of reproductive age (13 – 49 years old), and not of reproductive age (>49 years old). Logistic regression was used to estimate risk and its statistical significance. The model consists of gender and age correctly classified 83.5% of cases. Women were almost two times more likely to present as non-late testers compared to men, and reproductive age of 15 – 49 years were 1.5 times more likely to present as non-late testers compared to those with age > 49 years. Women affected by HIV almost in equal as for men. Women and those within reproductive age were more likely to present before the advanced stage compared to men and those aged > 49 years.

  8. On the use of thermal NF3 as the fluorination and oxidation agent in treatment of used nuclear fuels

    Science.gov (United States)

    Scheele, Randall; McNamara, Bruce; Casella, Andrew M.; Kozelisky, Anne

    2012-05-01

    This paper presents results of our investigation on the use of nitrogen trifluoride as a fluorination or fluorination/oxidation agent for separating valuable constituents from used nuclear fuels by exploiting the different volatilities of the constituent fission product and actinide fluorides. Our thermodynamic calculations show that nitrogen trifluoride has the potential to produce volatile fission product and actinide fluorides from oxides and metals that can form volatile fluorides. Simultaneous thermogravimetric and differential thermal analyses show that the oxides of lanthanum, cerium, rhodium, and plutonium are fluorinated but do not form volatile fluorides when treated with nitrogen trifluoride at temperatures up to 550 °C. However, depending on temperature, volatile fluorides or oxyfluorides can form from nitrogen trifluoride treatment of the oxides of niobium, molybdenum, ruthenium, tellurium, uranium, and neptunium. Thermoanalytical studies demonstrate near-quantitative separation of uranium from plutonium in a mixed 80% uranium and 20% plutonium oxide. Our studies of neat oxides and metals suggest that the reactivity of nitrogen trifluoride may be adjusted by temperature to selectively separate the major volatile fuel constituent uranium from minor volatile constituents, such as Mo, Tc, Ru and from the non-volatile fuel constituents based on differences in their reaction temperatures and kinetic behaviors. This reactivity is novel with respect to that reported for other fluorinating reagents F2, BrF5, ClF3.

  9. Thermal Methane Conversion to Syngas Mediated by Rh1-Doped Aluminum Oxide Cluster Cations RhAl3O4.

    Science.gov (United States)

    Li, Ya-Ke; Yuan, Zhen; Zhao, Yan-Xia; Zhao, Chongyang; Liu, Qing-Yu; Chen, Hui; He, Sheng-Gui

    2016-10-05

    Laser ablation generated RhAl 3 O 4 + heteronuclear metal oxide cluster cations have been mass-selected using a quadrupole mass filter and reacted with CH 4 or CD 4 in a linear ion trap reactor under thermal collision conditions. The reactions have been characterized by state-of-the-art mass spectrometry and quantum chemistry calculations. The RhAl 3 O 4 + cluster can activate four C-H bonds of a methane molecule and convert methane to syngas, an important intermediate product in methane conversion to value-added chemicals. The Rh atom is the active site for activation of the C-H bonds of methane. The high electron-withdrawing capability of Rh atom is the driving force to promote the conversion of methane to syngas. The polarity of Rh oxidation state is changed from positive to negative after the reaction. This study has provided the first example of methane conversion to syngas by heteronuclear metal oxide clusters under thermal collision conditions. Furthermore, the molecular level origin has been revealed for the condensed-phase experimental observation that trace amounts of Rh can promote the participation of lattice oxygen of chemically very inert support (Al 2 O 3 ) to oxidize methane to carbon monoxide.

  10. Sulfur-doped graphene via thermal exfoliation of graphite oxide in H2S, SO2, or CS2 gas.

    Science.gov (United States)

    Poh, Hwee Ling; Šimek, Petr; Sofer, Zdeněk; Pumera, Martin

    2013-06-25

    Doping of graphene with heteroatoms is an effective way to tailor its properties. Here we describe a simple and scalable method of doping graphene lattice with sulfur atoms during the thermal exfoliation process of graphite oxides. The graphite oxides were first prepared by Staudenmaier, Hofmann, and Hummers methods followed by treatments in hydrogen sulfide, sulfur dioxide, or carbon disulfide. The doped materials were characterized by scanning electron microscopy, high-resolution X-ray photoelectron spectroscopy, combustible elemental analysis, and Raman spectroscopy. The ζ-potential and conductivity of sulfur-doped graphenes were also investigated in this paper. It was found that the level of doping is more dramatically influenced by the type of graphite oxide used rather than the type of sulfur-containing gas used during exfoliation. Resulting sulfur-doped graphenes act as metal-free electrocatalysts for an oxygen reduction reaction.

  11. Thermal-hydraulics and neutronics studies on the FP7 CP-ESFR oxide and carbide cores

    Energy Technology Data Exchange (ETDEWEB)

    Ammirabile, L.; Tsige-Tamirat, H. [European Commission, JRC, Inst. for Energy, Petten (Netherlands)

    2011-07-01

    In the framework of the the Collaborative Project on European Sodium Fast Reactor (CP-ESFR) two core designs that are currently being proposed for the 3600 MWth sodium-cooled reactor concept: one is based on oxide fuel and the other on carbide fuel. Using the European Safety Assessment Platform (ESAP), JRC-IE has conducted static calculation on neutronics (incl. reactivity coefficients) and thermal-hydraulic characteristics for both oxide and carbide reference cores. The quantities evaluated include: keff, coolant heat-up, void, and Doppler reactivity coefficients, axial and radial expansion reactivity coefficients, pin-by-pin calculated power profiles, average and peak channel temperatures. This paper presents the ESAP models applied in the study together with the relevant results for the oxide and carbide core. (author)

  12. Thermal-hydraulics and neutronics studies on the FP7 CP-ESFR oxide and carbide cores

    International Nuclear Information System (INIS)

    Ammirabile, L.; Tsige-Tamirat, H.

    2011-01-01

    In the framework of the the Collaborative Project on European Sodium Fast Reactor (CP-ESFR) two core designs that are currently being proposed for the 3600 MWth sodium-cooled reactor concept: one is based on oxide fuel and the other on carbide fuel. Using the European Safety Assessment Platform (ESAP), JRC-IE has conducted static calculation on neutronics (incl. reactivity coefficients) and thermal-hydraulic characteristics for both oxide and carbide reference cores. The quantities evaluated include: keff, coolant heat-up, void, and Doppler reactivity coefficients, axial and radial expansion reactivity coefficients, pin-by-pin calculated power profiles, average and peak channel temperatures. This paper presents the ESAP models applied in the study together with the relevant results for the oxide and carbide core. (author)

  13. Comparative examination of the microstructure and high temperature oxidation performance of NiCrBSi flame sprayed and pack cementation coatings

    Science.gov (United States)

    Chaliampalias, D.; Vourlias, G.; Pavlidou, E.; Skolianos, S.; Chrissafis, K.; Stergioudis, G.

    2009-01-01

    Coatings formed from NiCrBSi powder were deposited by thermal spray and pack cementation processes on low carbon steel. The microstructure and morphology of the coatings were studied by scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). Flame sprayed coatings exhibited high porosity and were mechanically bonded to the substrate while pack cementation coatings were more compact and chemically bonded to the substrate. The microhardness and the high temperature oxidation resistance of the coated samples were evaluated by a Vickers microhardness tester and by thermogravimetric measurements (TG), respectively. Pack cementation coatings showed higher hardness and were more protective to high temperature environments than the flame sprayed coatings.

  14. Thermal conductivity evaluation of high burnup mixed-oxide (MOX) fuel pellet

    International Nuclear Information System (INIS)

    Amaya, Masaki; Nakamura, Jinichi; Nagase, Fumihisa; Fuketa, Toyoshi

    2011-01-01

    The thermal conductivity formula of fuel pellet which contains the effects of burnup and plutonium (Pu) addition was proposed based on the Klemens' theory and reported thermal conductivities of unirradiated (U, Pu) O 2 and irradiated UO 2 pellets. The thermal conductivity of high burnup MOX pellet was formulated by applying a summation rule between phonon scattering parameters which show the effects of plutonium addition and burnup. Temperature of high burnup MOX fuel was evaluated based on the thermal conductivity integral which was calculated from the above-mentioned thermal conductivity formula. Calculated fuel temperatures were plotted against the linear heat rates of the fuel rods, and were compared with the fuel temperatures measured in a test reactor. Since both values agreed well, it was confirmed that the proposed thermal conductivity formula of MOX pellets is adequate.

  15. Fabrication of oxide-free graphene suspension and transparent thin films using amide solvent and thermal treatment

    International Nuclear Information System (INIS)

    Oh, Se Young; Kim, Sung Hwan; Chi, Yong Seung; Kang, Tae Jin

    2012-01-01

    Graphical abstract: New methodology for suspended graphene sheets of high-quality (oxide-free), high-yield (high concentration) using amide solvent exfoliation and thermal treatment at 800 °C. We confirmed that the van der Waals force between the graphene layers decreases as increasing thermal treatment temperatures as shown XRD data (b). Highlights: ► Propose of new methodology to prepare oxide-free graphene sheets suspension. ► The graphene suspension concentration is enhanced by thermal treatment. ► Decrease of van der Waals force between the graphene layers by high temperature and pressure. ► This method has the potential as technology for mass production. ► It could be applied in transparent and flexible electronic devices. - Abstract: High quality graphene sheets were produced from graphite by liquid phase exfoliation using N-methyl-2-pyrrolidone (NMP) and a subsequent thermal treatment to enhance the exfoliation. The exfoliation was enhanced by treatment with organic solvent and high thermal expansion producing high yields of the high-quality and defect-free graphene sheets. The graphene was successfully deposited on a flexible and transparent polymer film using the vacuum filtration method. SEM images of thin films of graphene treated at 800 °C showed uniform structure with no defects commonly found in films made of graphene produced by other techniques. Thin films of graphene prepared at higher temperatures showed superior transmittance and conductivity. The sheet-resistance of the graphene film treated at 800 °C was 2.8 × 10 3 kΩ/□ with 80% transmittance.

  16. Microprocessor-controlled tester for evaluation of the Self-Energized Credential System (SECS)

    International Nuclear Information System (INIS)

    Corlis, N.E.

    1980-03-01

    The Self-Energized Credential System (SECS) was developed for use in the Plutonium Protection System (PPS) installed at Hanford, Washington. Evaluation and development of the SECS system was enhanced by the use of a microprocessor-controlled portal tester. This tester used infrared (ir) beam sensors to provide information on the direction of travel of the credential wearer and to detect inoperative credentials. A printed record of the portal number, actual code read, time, and direction of the credential passage provided information essential to an assessment of the operability of the SECS

  17. FPGA-based Bit-Error-Rate Tester for SEU-hardened Optical Links

    CERN Document Server

    Detraz, S; Moreira, P; Papadopoulos, S; Papakonstantinou, I; Seif El Nasr, S; Sigaud, C; Soos, C; Stejskal, P; Troska, J; Versmissen, H

    2009-01-01

    The next generation of optical links for future High-Energy Physics experiments will require components qualified for use in radiation-hard environments. To cope with radiation induced single-event upsets, the physical layer protocol will include Forward Error Correction (FEC). Bit-Error-Rate (BER) testing is a widely used method to characterize digital transmission systems. In order to measure the BER with and without the proposed FEC, simultaneously on several devices, a multi-channel BER tester has been developed. This paper describes the architecture of the tester, its implementation in a Xilinx Virtex-5 FPGA device and discusses the experimental results.

  18. Effect of thermal pre-treatment on the availability of PAHs for successive chemical oxidation in contaminated soils.

    Science.gov (United States)

    Usman, M; Chaudhary, A; Biache, C; Faure, P; Hanna, K

    2016-01-01

    This is the premier study designed to evaluate the impact of thermal pre-treatment on the availability of polycyclic aromatic hydrocarbons (PAHs) for successive removal by chemical oxidation. Experiments were conducted in two soils having different PAH distribution originating from former coking plant sites (Homécourt, H, and Neuves Maisons, NM) located in northeast of France. Soil samples were pre-heated at 60, 100, and 150 °C for 1 week under inert atmosphere (N2). Pre-heating resulted in slight removal of PAHs (soil samples were subjected to Fenton-like oxidation (H2O2 and magnetite) at room temperature. Chemical oxidation in soil without any pre-treatment showed almost no PAH degradation underscoring the unavailability of PAHs. However, chemical oxidation in pre-heated soils showed significant PAH degradation (19, 29, and 43% in NM soil and 31, 36, and 47% in H soil pre-treated at 60, 100, and 150 °C, respectively). No preferential removal of PAHs was observed after chemical oxidation in both soils. These results indicated the significant impact of pre-heating temperature on the availability of PAHs in contaminated soils and therefore may have strong implications in the remediation of contaminated soils especially where pollutant availability is a limiting factor.

  19. Mechanisms Underpinning Degradation of Protective Oxides and Thermal Barrier Coatings in High Hydrogen Content (HHC) - Fueled Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Mumm, Daniel

    2013-08-31

    The overarching goal of this research program has been to evaluate the potential impacts of coal-derived syngas and high-hydrogen content fuels on the degradation of turbine hot-section components through attack of protective oxides and thermal barrier coatings. The primary focus of this research program has been to explore mechanisms underpinning the observed degradation processes, and connections to the combustion environments and characteristic non-combustible constituents. Based on the mechanistic understanding of how these emerging fuel streams affect materials degradation, the ultimate goal of the program is to advance the goals of the Advanced Turbine Program by developing materials design protocols leading to turbine hot-section components with improved resistance to service lifetime degradation under advanced fuels exposures. This research program has been focused on studying how: (1) differing combustion environments – relative to traditional natural gas fired systems – affect both the growth rate of thermally grown oxide (TGO) layers and the stability of these oxides and of protective thermal barrier coatings (TBCs); and (2) how low levels of fuel impurities and characteristic non-combustibles interact with surface oxides, for instance through the development of molten deposits that lead to hot corrosion of protective TBC coatings. The overall program has been comprised of six inter-related themes, each comprising a research thrust over the program period, including: (i) evaluating the role of syngas and high hydrogen content (HHC) combustion environments in modifying component surface temperatures, heat transfer to the TBC coatings, and thermal gradients within these coatings; (ii) understanding the instability of TBC coatings in the syngas and high hydrogen environment with regards to decomposition, phase changes and sintering; (iii) characterizing ash deposition, molten phase development and infiltration, and associated corrosive

  20. Beryllium Project: developing in CDTN of uranium dioxide fuel pellets with addition of beryllium oxide to increase the thermal conductivity

    International Nuclear Information System (INIS)

    Ferreira, Ricardo Alberto Neto; Camarano, Denise das Merces; Miranda, Odair; Grossi, Pablo Andrade; Andrade, Antonio Santos; Queiroz, Carolinne Mol; Gonzaga, Mariana de Carvalho Leal

    2013-01-01

    Although the nuclear fuel currently based on pellets of uranium dioxide be very safe and stable, the biggest problem is that this material is not a good conductor of heat. This results in an elevated temperature gradient between the center and its lateral surface, which leads to a premature degradation of the fuel, which restricts the performance of the reactor, being necessary to change the fuel before its full utilization. An increase of only 5 to 10 percent in its thermal conductivity, would be a significant increase. An increase of 50 percent would be a great improvement. A project entitled 'Beryllium Project' was developed in CDTN - Centro de Desenvolvimento da Tecnologia Nuclear, which aimed to develop fuel pellets made from a mixture of uranium dioxide microspheres and beryllium oxide powder to obtain a better heat conductor phase, filling the voids between the microspheres to increase the thermal conductivity of the pellet. Increases in the thermal conductivity in the range of 8.6% to 125%, depending on the level of addition employed in the range of 1% to 14% by weight of beryllium oxide, were obtained. This type of fuel promises to be safer than current fuels, improving the performance of the reactor, in addition to last longer, resulting in great savings. (author)

  1. Performance evaluation of non-thermal plasma injection for elemental mercury oxidation in a simulated flue gas

    Energy Technology Data Exchange (ETDEWEB)

    An, Jiutao; Shang, Kefeng; Lu, Na [Institute of Electrostatics and Special Power, Dalian University of Technology, Dalian 116024 (China); Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education of the People' s Republic of China, Dalian 116024 (China); Jiang, Yuze [Shandong Electric Power Research Institute, Jinan 250002 (China); Wang, Tiecheng [Institute of Electrostatics and Special Power, Dalian University of Technology, Dalian 116024 (China); Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education of the People' s Republic of China, Dalian 116024 (China); Li, Jie, E-mail: lijie@dlut.edu.cn [Institute of Electrostatics and Special Power, Dalian University of Technology, Dalian 116024 (China); Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education of the People' s Republic of China, Dalian 116024 (China); Wu, Yan [Institute of Electrostatics and Special Power, Dalian University of Technology, Dalian 116024 (China); Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education of the People' s Republic of China, Dalian 116024 (China)

    2014-03-01

    Graphical abstract: - Highlights: • The use of non-thermal plasma injection approach to oxidize Hg{sup 0} in simulated flue gas at 110 °C was studied. • A high Hg{sup 0} oxidation efficiency was observed in the mixed flue gas that included O{sub 2}, H{sub 2}O, SO{sub 2}, NO and HCl. • Chemical and physical processes (e.g., ozone, N{sub 2} metastable states and UV-light) contributed to Hg{sup 0} oxidation. • Mercury species mainly existed in the form of HgO(s) adhering to the suspended aerosols in the gas-phase. - Abstract: The use of non-thermal plasma (NTP) injection approach to oxidize elemental mercury (Hg{sup 0}) in simulated flue gas at 110 °C was studied, where a surface discharge plasma reactor (SDPR) inserted in the simulated flue duct was used to generate and inject active species into the flue gas. Approximately 81% of the Hg{sup 0} was oxidized and 20.5 μg kJ{sup −1} of energy yield was obtained at a rate of 3.9 J L{sup −1}. A maximal Hg{sup 0} oxidation efficiency was found with a change in the NTP injection air flow rate. A high Hg{sup 0} oxidation efficiency was observed in the mixed flue gas that included O{sub 2}, H{sub 2}O, SO{sub 2}, NO and HCl. Chemical and physical processes (e.g., ozone, N{sub 2} metastable states and UV-light) were found to contribute to Hg{sup 0} oxidation, with ozone playing a dominant role. The deposited mercury species on the internal surface of the flue duct was analyzed using X-ray photoelectron spectroscopy (XPS) and electronic probe microanalysis (EPMA), and the deposit was identified as HgO. The mercury species is thought to primarily exist in the form of HgO(s) by adhering to the suspended aerosols in the gas-phase.

  2. Composition dependence of the kinetics and mechanisms of thermal oxidation of titanium-tantalum alloys

    International Nuclear Information System (INIS)

    Park, Y.S.; Butt, D.P.

    1999-01-01

    The oxidation behavior of titanium-tantalum alloys was investigated with respective concentrations of each element ranging from 0 to 100 wt.%. Alloys were exposed to argon-20% oxygen at 800 to 1400 C. The slowest oxidation rates were observed in alloys with 5--20% Ta. The oxidation kinetics of alloys containing less than approximately 40% Ta were approximately parabolic. Pure Ta exhibited nearly linear kinetics. Alloys containing 50% or more Ta exhibited paralinear kinetics. The activation energies for oxidation ranged between 232 kJ/mole for pure Ti and 119 kJ/mole for pure Ta, with the activation energies of the alloys falling between these values and generally decreasing with increasing Ta content. The activation energies for oxidation of the end members, Ti and Ta, agree well with published values for the activation energies for diffusion of oxygen in α-Ti and Ta. Scale formation in the alloys was found to be complex exhibiting various layers of Ti-, Ta-, and TiTa-oxides. The outermost layer of the oxidized alloys was predominantly rutile (TiO 2 ). Beneath the TiO 2 grew a variety of other oxides with the Ta content generally increasing with proximity to the metal-oxide interface. It was found that the most oxidation-resistant alloys had compositions falling between Ti-5Ta and Ti-15Ta. Although Ta stabilizes the β-phase of Ti, the kinetics of oxidation appeared to be rate limited by oxygen transport through the oxygen-stabilized α-phase. However, the kinetics are complicated by the formation of a complex oxide, which cracks periodically. Tantalum appears to increase the compositional range of oxygen-stabilized α-phase and reduces both the solubility of oxygen and diffusivity of Ti in the α- and β-phases

  3. Exchange bias coupling in NiO/Ni bilayer tubular nanostructures synthetized by electrodeposition and thermal oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Yu, T., E-mail: work_tian@scu.edu.cn [College of Physical Science and Technology, Sichuan University, Chengdu 610064 (China); Zhang, Z.W.; Xu, Y.H. [College of Physical Science and Technology, Sichuan University, Chengdu 610064 (China); Liu, Y. [Analytical & Testing Center, Sichuan University, Chengdu 610064 (China); Li, W.J. [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190 (China); Nie, Y.; Zhang, X. [College of Physical Science and Technology, Sichuan University, Chengdu 610064 (China); Xiang, G., E-mail: gxiang@scu.edu.cn [College of Physical Science and Technology, Sichuan University, Chengdu 610064 (China)

    2017-05-01

    In this paper, we reported the synthesis of NiO/Ni bilayer nanotubes by electrodeposition and thermal oxidation using anodic aluminum oxide templates. The morphology, structure, chemical composition and magnetic properties, especially magnetic exchange bias induced by subsequent magnetic field cooling, in this one-dimensional antiferromagnetic/ferromagnetic hybrid system were investigated. It was found that the effect of the annealing temperature, which mainly dominated the thickness of the NiO layer, and the annealing time, which mainly dominated the grain size of the NiO, on the exchange bias field showed competitive relationship. The optimized exchange bias field was achieved by the combination of the shorter annealing time and higher annealing temperature. - Highlights: • NiO-Ni bilayer tubular nanotubes were fabricated by electrodeposition and thermal oxidation. • The exchange bias effect in NiO-Ni nanotubes was induced by magnetic field cooling. • The competitive effect of annealing temperature and annealing time on the exchange bias coupling was analyzed.

  4. Thermal Degradation Kinetics Modeling of Benzophenones and Xanthones during High-Temperature Oxidation of Cyclopia genistoides (L.) Vent. Plant Material.

    Science.gov (United States)

    Beelders, Theresa; de Beer, Dalene; Joubert, Elizabeth

    2015-06-10

    Degradation of the major benzophenones, iriflophenone-3-C-glucoside-4-O-glucoside and iriflophenone-3-C-glucoside, and the major xanthones, mangiferin and isomangiferin, of Cyclopia genistoides followed first-order reaction kinetics during high-temperature oxidation of the plant material at 80 and 90 °C. Iriflophenone-3-C-glucoside-4-O-glucoside was shown to be the most thermally stable compound. Isomangiferin was the second most stable compound at 80 °C, while its degradation rate constant was influenced the most by increased temperature. Mangiferin and iriflophenone-3-C-glucoside had comparable degradation rate constants at 80 °C. The thermal degradation kinetic model was subsequently evaluated by subjecting different batches of plant material to oxidative conditions (90 °C/16 h). The model accurately predicted the individual contents of three of the compounds in aqueous extracts prepared from oxidized plant material. The impact of benzophenone and xanthone degradation was reflected in the decreased total antioxidant capacity of the aqueous extracts, as determined using the oxygen radical absorbance capacity and DPPH(•) scavenging assays.

  5. Evaluation of the synergistic interaction between Decarbomobiphenyl Oxide and alumina on the flammability and thermal behavior of unsaturated polyester resin

    International Nuclear Information System (INIS)

    Al-Owias, A.; Al-Haizan, A.; Khattab, M. A.

    2005-01-01

    The bromine performance of decarbomobiphenyl oxide (DBBO) as a flame retardant for unsaturated polyester resin (UP) had been investigated in its own and in the presence of aluminum oxide (Al2O3) using UL-94V and Limiting Oxygen Index (LOI). Thermal behaviors of the resulted systems were evaluated using thermal analysis technique. DBBO showed a satisfactory fire retardant performance for UP, particularly when used at a loading higher than 30 wt%. In contrast aluminum oxide has no significant effect on the reduction of the flammability. Treatment of UP with mixtures containing different portioned of DBBO and alumina showed that, the best performance of these mixtures as a flame retardant occurred when the mixture is rich in DBBO. The maximum synergism between the two additives has been observed to occur at a weight ratio of DBBO to Al2O3 of 5:6. A possible explanation for the observed synergism between the two additives was given. The synergism was partly attributed to the formation of aluminum halide species which enhance the rate of halogen released from the halogenated compound and consequently reduce the flammability of the resin. (author)

  6. Rapid thermal processing of nano-crystalline indium tin oxide transparent conductive oxide coatings on glass by flame impingement technology

    International Nuclear Information System (INIS)

    Schoemaker, S.; Willert-Porada, M.

    2009-01-01

    Indium tin oxide (ITO) is still the best suited material for transparent conductive oxides, when high transmission in the visible range, high infrared reflection or high electrical conductivity is needed. Current approaches on powder-based printable ITO coatings aim at minimum consumption of active coating and low processing costs. The paper describes how fast firing by flame impingement is used for effective sintering of ITO-coatings applied on glass. The present study correlates process parameters of fast firing by flame impingement with optoelectronic properties and changes in the microstructure of suspension derived nano-particulate films. With optimum process parameters the heat treated coatings had a sheet resistance below 0.5 kΩ/ □ combined with a transparency higher than 80%. To characterize the influence of the burner type on the process parameters and the coating functionality, two types of methane/oxygen burner were compared: a diffusion burner and a premixed burner

  7. Insight into the Mechanism of the Thermal Reduction of Graphite Oxide: Deuterium-Labeled Graphite Oxide Is the Key

    Czech Academy of Sciences Publication Activity Database

    Sofer, Z.; Jankovský, O.; Šimek, P.; Sedmidubský, D.; Šturala, J.; Kosina, J.; Mikšová, Romana; Macková, Anna; Mikulics, M.; Pumera, M.

    2015-01-01

    Roč. 9, č. 5 (2015), s. 5478-5485 ISSN 1936-0851 R&D Projects: GA ČR(CZ) GA15-09001S; GA ČR(CZ) GBP108/12/G108 Grant - others:GA MŠk(CZ) LM2010005 Institutional support: RVO:61389005 Keywords : graphene * exfoliation * mechanism * isotope labeling * graphite oxide Subject RIV: BG - Nuclear , Atomic and Molecular Physics, Colliders Impact factor: 13.334, year: 2015

  8. Thermal ramp rate effects on mixed-oxide fuel swelling/gas release

    International Nuclear Information System (INIS)

    Hinman, C.A.; Randklev, E.H.

    1979-01-01

    Macroscopic swelling behavior of PNL-10 was compared to that of PNL-2 fuel and it was found that the swelling-threshold behavior is similar for similar thermal conditions. Transient fission gas release for the PNL-10 fuel is very similar to that observed for the PNL-2 fuel for similar thermal conditions

  9. Effects of β-carotene on the thermal oxidation of fatty acids | Zeb ...

    African Journals Online (AJOL)

    β-Carotene is one of the most important fat soluble pigment with well known antioxidant and provitamin A activities. It is used in industries as food colorant and a source of vitamin A. The thermal induced degradation during processing leads to color and properties losses. The thermal stability of the fatty acids composition of ...

  10. Stress hysteresis during thermal cycling of plasma-enhanced chemical vapor deposited silicon oxide films

    Science.gov (United States)

    Thurn, Jeremy; Cook, Robert F.

    2002-02-01

    The mechanical response of plasma-enhanced chemical vapor deposited SiO2 to thermal cycling is examined by substrate curvature measurement and depth-sensing indentation. Film properties of deposition stress and stress hysteresis that accompanied thermal cycling are elucidated, as well as modulus, hardness, and coefficient of thermal expansion. Thermal cycling is shown to result in major plastic deformation of the film and a switch from a compressive to a tensile state of stress; both athermal and thermal components of the net stress alter in different ways during cycling. A mechanism of hydrogen incorporation and release from as-deposited silanol groups is proposed that accounts for the change in film properties and state of stress.

  11. Reliability of knee joint range of motion and circumference measurements after total knee arthroplasty: does tester experience matter?

    DEFF Research Database (Denmark)

    Jakobsen, Thomas Linding; Christensen, Malene; Christensen, Stine Sommer

    2010-01-01

    : The design was an intra-tester, inter-tester and intra-day reliability study. Nineteen outpatients (10 females) having received a TKA were examined by an inexperienced and an experienced physiotherapist. Following a standardized protocol, active and passive knee joint ROM and circumference measurements were...

  12. 16 CFR Figure 4 to Subpart A of... - Flooring Radiant Panel Tester Schematic Low Flux End, Elevation

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Flooring Radiant Panel Tester Schematic Low Flux End, Elevation 4 Figure 4 to Subpart A of Part 1209 Commercial Practices CONSUMER PRODUCT SAFETY... Standard Pt. 1209, Subpt. A, Fig. 4 Figure 4 to Subpart A of Part 1209—Flooring Radiant Panel Tester...

  13. Relating the octane numbers of fuels to ignition delay times measured in an ignition quality tester (IQT)

    KAUST Repository

    Naser, Nimal; Yang, Seung Yeon; Kalghatgi, Gautam; Chung, Suk-Ho

    2016-01-01

    an ignition quality tester. A baseline data of ignition delay times were determined using an ignition quality tester at a charge pressure of 21.3 bar between 770 and 850 K and an equivalence ratio of 0.7 for various primary reference fuels (PRFs, mixtures

  14. Thermal Conductivity of Wurtzite Zinc-Oxide from First-Principles Lattice Dynamics – a Comparative Study with Gallium Nitride

    Science.gov (United States)

    Wu, Xufei; Lee, Jonghoon; Varshney, Vikas; Wohlwend, Jennifer L.; Roy, Ajit K.; Luo, Tengfei

    2016-01-01

    Wurtzite Zinc-Oxide (w-ZnO) is a wide bandgap semiconductor that holds promise in power electronics applications, where heat dissipation is of critical importance. However, large discrepancies exist in the literature on the thermal conductivity of w-ZnO. In this paper, we determine the thermal conductivity of w-ZnO using first-principles lattice dynamics and compare it to that of wurtzite Gallium-Nitride (w-GaN) – another important wide bandgap semiconductor with the same crystal structure and similar atomic masses as w-ZnO. However, the thermal conductivity values show large differences (400 W/mK of w-GaN vs. 50 W/mK of w-ZnO at room temperature). It is found that the much lower thermal conductivity of ZnO originates from the smaller phonon group velocities, larger three-phonon scattering phase space and larger anharmonicity. Compared to w-GaN, w-ZnO has a smaller frequency gap in phonon dispersion, which is responsible for the stronger anharmonic phonon scattering, and the weaker interatomic bonds in w-ZnO leads to smaller phonon group velocities. The thermal conductivity of w-ZnO also shows strong size effect with nano-sized grains or structures. The results from this work help identify the cause of large discrepancies in w-ZnO thermal conductivity and will provide in-depth understanding of phonon dynamics for the design of w-ZnO-based electronics. PMID:26928396

  15. Surface and sub-surface thermal oxidation of ruthenium thin films

    NARCIS (Netherlands)

    Coloma Ribera, R.; van de Kruijs, Robbert Wilhelmus Elisabeth; Zoethout, E.; Yakshin, Andrey; Bijkerk, Frederik

    2014-01-01

    For next generation Extreme UV photolithography, multilayer coatings may require protective capping layers against surface contamination. Ruthenium, as a low-oxidation metal, is often used as a reference material. The oxidation behaviour of Ru thin films has been studied using X-ray reflectometry

  16. HREM investigation of the constitution and the crystallography of thin thermal oxide layers on iron

    DEFF Research Database (Denmark)

    Graat, P.C.J.; Brongers, M.P.H.; Zandbergen, H.W.

    1997-01-01

    Oxide layers formed at 573 K in O2 at atmospheric pressure, both on a clean iron surface and on an iron surface covered with an etching induced (hydro)oxide film, were investigated with high-resolution transmission electron microscopy (HREM). Cross-sections of oxidised samples were prepared by a ...

  17. Optical properties and thermal stability of LaYbO3 ternary oxide for high-k dielectric application

    Science.gov (United States)

    Su, Wei-tao; Yang, Li; Li, Bin

    2011-01-01

    A new ternary rare oxide dielectric LaYbO3 film had been prepared on silicon wafers and quartz substrates by reactive sputtering method using a La-Yb metal target. A range of analysis techniques was performed to determine the optical band gap, thermal stability, and electrical property of the deposited samples. It was found the band gap of LaYbO3 film was about 5.8 eV. And the crystallization temperature for rapid thermal annealing (20 s) was between 900 and 950 °C. X-ray photoelectron spectroscopy results indicate the formation of the SiO2 and silicate in the interface between silicon wafer and LaYbO3 film. The dielectric constant is about 23 from the calculation of capacitance-voltage curve, which is comparable higher than previously reported La2O3 or Yb2O3 film.

  18. Thermal properties of rare earth cobalt oxides and of La1- x Gd x CoO3 solid solutions

    Science.gov (United States)

    Orlov, Yu. S.; Dudnikov, V. A.; Gorev, M. V.; Vereshchagin, S. N.; Solov'ev, L. A.; Ovchinnikov, S. G.

    2016-05-01

    Powder X-ray diffraction data for the crystal structure, phase composition, and molar specific heat for La1‒ x Gd x CoO3 cobaltites in the temperature range of 300-1000 K have been analyzed. The behavior of the volume thermal expansion coefficient in cobaltites with isovalent doping in the temperature range of 100-1000 K is studied. It is found that the β( T) curve exhibits two peaks at some doping levels. The rate of the change in the occupation number for the high-spin state of cobalt ions is calculated for the compounds under study taking into account the spin-orbit interaction. With the Birch-Murnaghan equation of state, it is demonstrated that the low-temperature peak in the thermal expansion shifts with the growth of the pressure toward higher temperatures and at pressure P ˜ 7 GPa coincides with the second peak. The similarity in the behavior of the thermal expansion coefficient in the La1- x Gd x CoO3 compounds with the isovalent substitution and the undoped LnCoO3 compound (Ln is a lanthanide) is considered. For the whole series of rare earth cobalt oxides, the nature of two specific features in the temperature dependence of the specific heat and thermal expansion is revealed and their relation to the occupation number for the high-spin state of cobalt ions and to the insulator-metal transition is established.

  19. Effects of Surface Nitrification on Thermal Conductivity of Modified Aluminum Oxide Nanofibers-Reinforced Epoxy Matrix Nanocomposites

    International Nuclear Information System (INIS)

    Kim, Byungjoo; Bae, Kyongmin; An, Kayhyeok; Park, Soojin

    2012-01-01

    Aluminum oxide (Al 2 O 3 ) nanofibers were treated thermally under an ammonia (NH 3 ) gas stream balanced by nitrogen to form a thin aluminum nitride (AlN) layer on the nanofibers, resulting in the enhancement of thermal conductivity of Al 2 O 3 /epoxy nanocomposites. The micro-structural and morphological properties of the NH 3 -assisted thermally-treated Al 2 O 3 nanofibers were characterized by X-ray diffraction (XRD) and atomic force microscopy (AEM), respectively. The surface characteristics and pore structures were observed by X-ray photoelectron spectroscopy (XPS), Zeta-potential and N 2 /77 K isothermal adsorptions. From the results, the formation of AlN on Al 2 O 3 nanofibers was confirmed by XRD and XPS. The thermal conductivity (TC) of the modified Al 2 O 3 nanofibers/epoxy composites increased with increasing treated temperatures. On the other hand, the severely treated Al 2 O 3 /epoxy composites showed a decrease in TC, resulting from a decrease in the probability of heat-transfer networks between the filler and matrix in this system due to the aggregation of nanofiber fillers

  20. Investigation of the effect of support thermal treatment on gold-based catalysts' activity towards propene total oxidation

    International Nuclear Information System (INIS)

    Lamallem, M.; Cousin, R.; Thomas, R.; Siffert, St.; Aissi, F.; Aboukais, A.

    2009-01-01

    This paper reports a study on the effect of support thermal treatment on the activity of gold-based catalysts for the total oxidation of propene. Ce 0.3 Ti 0.7 O 2 supports were prepared using sol-gel method. These compounds are calcined at 400, 500 and 600 C. Physico-chemical properties of synthesized materials were characterized by means of XRD, DR/UV-vis and H 2 -TPR. Then gold was deposited on these supports by the deposition precipitation method. Thus the catalytic activity of these solids in the propene oxidation was evaluated. On the basis of the catalytic results, a better activity is obtained when gold is deposited on Ce 0.3 Ti 0.7 O 2 support previously calcined at 400 C under air. (authors)

  1. Thermal conductivity of beginning-of-life uranium-plutonium mixed oxide fuel for fast reactor (Interim report)

    International Nuclear Information System (INIS)

    Inoue, Masaki; Mizuno, Tomoyasu; Asaga, Takeo

    1997-11-01

    Thermal conductivity of uranium-plutonium mixed oxide fuel for fast reactor at beginning-of-life was correlated based on the recent results in order to apply to the fuel design and the fuel performance analysis. A number of experimental results of unirradiated fuel specimens were corrected from open literatures and PNC internal reports and examined for the database. In this work two porosity correction factors were needed for high density fuel and low density fuel (around the current Monju specification). The universal porosity correction factor was not determined in this work. In the next step, theoretical and analytical considerations should be taken into account. (J.P.N.)

  2. Development of composite ceramic materials with improved thermal conductivity and plasticity based on garnet-type oxides

    Science.gov (United States)

    Golovkina, L. S.; Orlova, A. I.; Boldin, M. S.; Sakharov, N. V.; Chuvil'deev, V. N.; Nokhrin, A. V.; Konings, R.; Staicu, D.

    2017-06-01

    Powders based on the complex garnet-type oxide Y2.5Nd0.5Al5O12 - x wt. % Ni (x = 0, 10, 20) were prepared using wet chemistry methods. Ceramics based on these compounds were obtained by Spark Plasma Sintering (SPS) with a relative densities: 99%. 4% (TD = 4.77 g/cm3 (0%)), 97.6% (TD = 4.88 g/cm3 (10%)), 94.4% (TD = 5.06 g/cm3 (20%)). The influence of nickel concentration on the mechanical (fracture toughness, microhardness) and thermophysical (thermal conductivity) properties of the composites was studied.

  3. Comparison of stabilization by Vitamin E and 2,6-di-tert-butylphenols during polyethylene radio-thermal-oxidation

    Science.gov (United States)

    Richaud, Emmanuel

    2014-10-01

    This paper reports a compilation of data for PE+Vitamin E and 2,6-di-tert-butylphenols oxidation in radio-thermal ageing. Data unambiguously show that Vitamin E reacts with Prad and POOrad whereas 2,6-di-tert-butyl phenols only react with POOrad. Kinetic parameters of the stabilization reactions for both kinds of antioxidants were tentatively extracted from phenol depletion curves, and discussed regarding the structure of the stabilizer. They were also used for completing an existing kinetic model used for predicting the stabilization by antioxidants. This one permits to compare the efficiency of stabilizer with dose rate or sample thickness.

  4. The effect of lunar soil, metal oxides on thermal and radio-chemical stability of amino acids

    International Nuclear Information System (INIS)

    Khenokh, M.A.; Lapinskaya, E.M.

    1983-01-01

    Data on study of the effect of lunar soil and some metal oxides characteristic both for land and sea basaltS of lunar sojls on thermal and radio-chemical stability of amino acids are presented. The data obtained permit to suppose that extremely small quantity of amino acids discovered in lunar soil is conditioned by their decomposition under combined effect of different types of radiation, solar wind and sharp change of temperature. Probably, the effect of soil on photochemical activity of UV-radiation of the Sun and solid-phase radiolysis is not practically observed

  5. Rheological behavior, chemical and physical characterization of soybean and cottonseed methyl esters submitted to thermal oxidation process

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Adriano Sant' ana; Silva, Flavio Luiz Honorato da; Lima, Ezenildo Emanuel de; Carvalho, Maria Wilma N.C. [Universidade Federal de Campina Grande (CCT/UFCG), PB (Brazil). Centro de Ciencia e Tecnologia; Dantas, Hemeval Jales; Farias, Paulo de Almeida [Universidade Federal de Campina Grande (CTRN/UFCG), PB (Brazil). Centro de Tecnologia e Recursos Naturais

    2008-07-01

    In this study the effect of antioxidant terc-butylhydroxyanisol (BHA) on the oxidative stability of soybean and cottonseed methyl esters subjected to thermal degradation at 100 deg C was studied. Soybean and cottonseed methyl esters specific mass, dynamic viscosity and rheological behavior were evaluated. According to results, antioxidant degraded samples specific mass and dynamic viscosity did not showed alterations, remaining statistically equal. Soybean and cottonseed methyl esters showed a Newtonian rheological behavior and degraded samples without adding BHA showed rheological behavior alterations. (author)

  6. Effects of high-temperature thermal annealing on the electronic properties of In-Ga-Zn oxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Li, Qin; Song, Zhong Xiao; Ma, Fei, E-mail: mafei@mail.xjtu.edu.cn, E-mail: liyhemail@gmail.com; Li, Yan Huai, E-mail: mafei@mail.xjtu.edu.cn, E-mail: liyhemail@gmail.com [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China); Xu, Ke Wei [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an, Shaanxi 710049, China and Department of Physics and Opt-electronic Engineering, Xi' an University of Arts and Science, Xi' an, Shaanxi 710065 (China)

    2015-03-15

    Indium gallium zinc oxide (IGZO) thin films were deposited by radio-frequency magnetron sputtering at room-temperature. Then, thermal annealing was conducted to improve the structural ordering. X-ray diffraction and high-resolution transmission electron microscopy demonstrated that the as-deposited IGZO thin films were amorphous and crystallization occurred at 800 and 950 °C. As a result of crystallization at high temperature, the carrier concentration and the Hall mobility of IGZO thin films were sharply increased, which could be ascribed to the increased oxygen vacancies and improved structural ordering of the thin films.

  7. Ex-Situ and In-Situ Ellipsometric Studies of the Thermal Oxide on InP

    Science.gov (United States)

    1990-12-06

    ion---- Distribution/ Availabilit ? Codes£v l llt Codes Avail and/or Dist| Special Abstract The thermally grown InP oxide as etched by an aqueous...aqueous NH4OH/NH4F, and Law(17) has reported observations of orientational ordering of water and organic solvents on pyrex surfaces by in-situ...minutes, followed by a sequence of acetone, deionized water (d. i. water ) rinse. After being dipped in a concentrated aqueous HF solution for 15 seconds

  8. Microwave-assisted hydrothermal synthesis of coralloid nanostructured nickel hydroxide hydrate and thermal conversion to nickel oxide

    International Nuclear Information System (INIS)

    Lai, Teh-Long; Lai, Yuan-Lung; Yu, Jen-Wei; Shu, Youn-Yuen; Wang, Chen-Bin

    2009-01-01

    Coralloid nanostructured nickel hydroxide hydrate has been successfully synthesized by a simple microwave-assisted hydrothermal process using nickel sulfate hexahydrate as precursor and urea as hydrolysis-controlling agent. A pure coralloid nanostructured nickel oxide can be obtained from the nickel hydroxide hydrate after calcination at 400 deg. C. The thermal property, structure and morphology of samples were characterized by thermogravimetry (TG), temperature-programmed reduction (TPR), X-ray (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

  9. Microwave-assisted hydrothermal synthesis of coralloid nanostructured nickel hydroxide hydrate and thermal conversion to nickel oxide

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Teh-Long [Environmental Analysis Laboratory, Department of Chemistry, National Kaohsiung Normal University, Kaohsiung 802, Taiwan (China); Lai, Yuan-Lung [Department of Mechanical and Automation Engineering, Da-Yeh University, Changhua 515, Taiwan (China); Yu, Jen-Wei [Environmental Analysis Laboratory, Department of Chemistry, National Kaohsiung Normal University, Kaohsiung 802, Taiwan (China); Shu, Youn-Yuen, E-mail: shuyy@nknucc.nknu.edu.tw [Environmental Analysis Laboratory, Department of Chemistry, National Kaohsiung Normal University, Kaohsiung 802, Taiwan (China); Wang, Chen-Bin, E-mail: chenbin@ccit.edu.tw [Department of Applied Chemistry and Materials Science, Chung Cheng Institute of Technology, National Defense University, Tahsi, Taoyuan 335, Taiwan (China)

    2009-10-15

    Coralloid nanostructured nickel hydroxide hydrate has been successfully synthesized by a simple microwave-assisted hydrothermal process using nickel sulfate hexahydrate as precursor and urea as hydrolysis-controlling agent. A pure coralloid nanostructured nickel oxide can be obtained from the nickel hydroxide hydrate after calcination at 400 deg. C. The thermal property, structure and morphology of samples were characterized by thermogravimetry (TG), temperature-programmed reduction (TPR), X-ray (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

  10. Usefulness of new wetness tester for diagnosis of dry mouth in disabled patients.

    Science.gov (United States)

    Kakinoki, Yasuaki; Nishihara, Tatsuji; Arita, Masahiro; Shibuya, Koji; Ishikawa, Masao

    2004-12-01

    The condition of dry mouth is an influential factor in the incidence of caries, periodontal disease, fungal infections, masticatory dysfunctions and denture function. Bedridden elderly and disabled persons often suffer from oral dryness and the aim of this study was to evaluate the usefulness of measuring the amount of moisture in the oral mucosa for clinical diagnosis of dry mouth in this group. The subjects were 20 elderly bedridden individuals, age range 65-89 years old, living in a nursing home and six healthy laboratory researchers, aged 20-46 years old, used as controls. Tongue dorsum moisture measurements were performed using a newly developed wetness tester (L-SALIVO), in which the wet portion was measured after 10 s. Further, clinical diagnosis of dry mouth was carried out using a clinical classification scale of the tongue mucosa (grade range, 0-3). It was possible to measure tongue dorsum moisture in all subjects with the wetness tester. The average moisture value was 0.1+/-0.2 mm in elderly subjects with a dry mouth grade of 2 (n = 8) or 3 (n = 12), while the average moisture value in the control subjects was 3.67+/-1.75 mm with a dry mouth grade of 0 (n = 4) or 1 (n = 2). Tester values and cliniical classification showed a positive co-relationship (r = 0.31, p < 0.05). Our results show that this new tester could be useful for evaluating oral dryness and diagnosing dry mouth.

  11. Evaluation of Next-Generation Vision Testers for Aeromedical Certification of Aviation Personnel

    Science.gov (United States)

    2009-07-01

    measure distant, intermediate, and near acuity. The slides are essentially abbreviated versions of the Early Treatment for Diabetic Retinopathy Study...over, requiring intermediate vision testing and 12 were color deficient. Analysis was designed to detect statistically significant differences between...Vertical Phoria (Right & Left Hyperphoria) Test scores from each of the vision testers were collated and analyzed. Analysis was designed to detect

  12. Development of new design mechanical seal tester for Primary Loop Recirculation Pump (PLR Pump)

    International Nuclear Information System (INIS)

    Fukushima, Naoki; Koshiba, Koremutsu

    1995-01-01

    The mechanical seal for a Primary Loop Recirculation Pump (PLR Pump) is an important part of a BWR plant. This study describes a new mechanical seal tester developed to certify mechanical seal performance before installation in a PLR Pump on site. (author)

  13. Formation of polymerization compounds during thermal oxidation of cottonseed oil, partially hydrogenated cottonseed oil and their blends

    Directory of Open Access Journals (Sweden)

    Barrera-Arellano, D. Laboratório de Óleos e Gorduras, Departa

    2006-09-01

    Full Text Available Samples of cottonseed oil, partially hydrogenated cottonseed oil and their blends, with iodine values between 60 and 110, tocopherol-stripped or not by aluminium oxide treatment, were submitted to thermal oxidation, at 180 °C, for 10 hours. Samples were collected at 0, 2, 5, 8 and 10 hours, for the determination of dimers and polymers (degradation compounds and of tocopherols. The influence of the degree of hydrogenation on the formation of dimers and polymers and the role of originally present tocopherols in the protection of fats and oils against thermal degradation was verified. The degradation curves for tocopherols showed a fast destruction rate for the tocopherols present in cottonseed fats and oil (α and γ-tocopherols, with residual levels close to zero after 10 hours under thermal oxidation conditions. Nevertheless, samples with their natural tocopherols presented a slower rate of thermal degradation. The unsaturation degree was apparently more important in the protection against thermal degradation than the content of tocopherolsMuestras de aceite de algodón, aceite de algodón parcialmente hidrogenado y sus mezclas, con índices de yodo de 60 a 110, tratadas o no con óxido de aluminio, fueron sometidas a termoxidación, a 180 °C, durante 10 horas. Se retiraron muestras en los tiempos 0, 2, 5, 8 y 10 horas, para determinación de dímeros y polímeros (compuestos de degradación y de tocoferoles. Se verificó la influencia del grado de hidrogenación sobre la formación de dímeros y polímeros, y también el papel de los tocoferoles originalmente presentes en el aceite y en las grasas, en la protección contra la degradación térmica. Las curvas de degradación de los tocoferoles mostraron una destrucción bastante rápida de los tocoferoles presentes en el aceite y en las grasas de algodón (α y γ-tocoferoles, con niveles residuales próximos a cero después de 10 horas de termoxidación. Aún así, muestras con sus

  14. Studies Of Oxidation And Thermal Reduction Of The Cu(100) Surface Using Positron Annihilation Induced Auger Electron Spectroscopy

    Science.gov (United States)

    Fazleev, N. G.; Nadesalingam, M. P.; Maddox, W.; Weiss, A. H.

    2011-06-01

    Positron annihilation induced Auger electron spectroscopy (PAES) measurements from the surface of an oxidized Cu(100) single crystal show a large increase in the intensity of the annihilation induced Cu M2,3VV Auger peak as the sample is subjected to a series of isochronal anneals in vacuum up to annealing temperature 300 °C. The PAES intensity then decreases monotonically as the annealing temperature is increased to ˜550 °C. Experimental positron annihilation probabilities with Cu 3p and O 1s core electrons are estimated from the measured intensities of the positron annihilation induced Cu M2,3VV and O KLL Auger transitions. PAES results are analyzed by performing calculations of positron surface states and annihilation probabilities of the surface-trapped positrons with relevant core electrons taking into account the charge redistribution at the surface and various surface structures associated with low and high oxygen coverages. The variations in atomic structure and chemical composition of the topmost layers of the oxidized Cu(100) surface are found to affect localization and spatial extent of the positron surface state wave function. The computed positron binding energy and annihilation characteristics reveal their sensitivity to charge transfer effects, atomic structure and chemical composition of the topmost layers of the oxidized Cu(100) surface. Theoretical positron annihilation probabilities with Cu 3p and O 1s core electrons computed for the oxidized Cu(100) surface are compared with experimental ones. The obtained results provide a demonstration of thermal reduction of the copper oxide surface after annealing at 300 °C followed by re-oxidation of the Cu(100) surface at higher annealing temperatures presumably due to diffusion of subsurface oxygen to the surface.

  15. Studies Of Oxidation And Thermal Reduction Of The Cu(100) Surface Using Positron Annihilation Induced Auger Electron Spectroscopy

    International Nuclear Information System (INIS)

    Fazleev, N. G.; Nadesalingam, M. P.; Maddox, W.; Weiss, A. H.

    2011-01-01

    Positron annihilation induced Auger electron spectroscopy (PAES) measurements from the surface of an oxidized Cu(100) single crystal show a large increase in the intensity of the annihilation induced Cu M2,3VV Auger peak as the sample is subjected to a series of isochronal anneals in vacuum up to annealing temperature 300 deg. C. The PAES intensity then decreases monotonically as the annealing temperature is increased to ∼550 deg. C. Experimental positron annihilation probabilities with Cu 3p and O 1s core electrons are estimated from the measured intensities of the positron annihilation induced Cu M 2,3 VV and O KLL Auger transitions. PAES results are analyzed by performing calculations of positron surface states and annihilation probabilities of the surface-trapped positrons with relevant core electrons taking into account the charge redistribution at the surface and various surface structures associated with low and high oxygen coverages. The variations in atomic structure and chemical composition of the topmost layers of the oxidized Cu(100) surface are found to affect localization and spatial extent of the positron surface state wave function. The computed positron binding energy and annihilation characteristics reveal their sensitivity to charge transfer effects, atomic structure and chemical composition of the topmost layers of the oxidized Cu(100) surface. Theoretical positron annihilation probabilities with Cu 3p and O 1s core electrons computed for the oxidized Cu(100) surface are compared with experimental ones. The obtained results provide a demonstration of thermal reduction of the copper oxide surface after annealing at 300 deg. C followed by re-oxidation of the Cu(100) surface at higher annealing temperatures presumably due to diffusion of subsurface oxygen to the surface.

  16. Physicochemical, structural and thermal properties of oxidized, acetylated and dual-modified common bean (Phaseolus vulgaris L. starch

    Directory of Open Access Journals (Sweden)

    José Pedro WOJEICCHOWSKI

    2018-03-01

    Full Text Available Abstract Common beans are rich in protein and complex carbohydrates that are valuable for the human diet. Starch is the most abundant individual component; however, in its native form it has limited applications and modifications are necessary to overcome technological restrictions. The aim of this study was to evaluate the influence of oxidation, acetylation and dual-modification (oxidation-acetylation on the physicochemical, structural and thermal properties of common bean starch. The degree of substitution of the acetylated starches was compatible with food use. Fourier transform infrared spectra confirmed the acetylation of the bean starch, with a peak at 1,735cm-1. The granules of the bean starch were oval to spherical in shape, with no differences between the native and modified samples. Typical C-type diffraction of legume starches was found. The modified samples showed a reduced relative crystallinity and lower enthalpy change of gelatinization. The oxidized starch showed the highest peak viscosity, hardness, and gel adhesiveness due to the presence of functional groups. An increase in solubility and swelling power was observed, and the oxidized-acetylated starch presented the highest values. The properties of the modified bean starches made them suitable for application in breaded/battered foods, mainly due to improved textural attributes.

  17. Enhancing the Photovoltage of Ni/ n-Si Photoanode for Water Oxidation through a Rapid Thermal Process.

    Science.gov (United States)

    Li, Shengyang; She, Guangwei; Chen, Cheng; Zhang, Shaoyang; Mu, Lixuan; Guo, Xiangxin; Shi, Wensheng

    2018-03-14

    The Ni in the Ni/ n-Si photoanode can not only protect Si from corrosion, but also catalyze the water oxidation reaction. However, the high density of interface states at the Ni/ n-Si interface could pin the Fermi level of silicon, which will lower the Schottky barrier height of the Ni/ n-Si. As a result, a low photovoltage and consequent high onset potential of Ni/ n-Si photoanode for water oxidation were generated. In this study, the interfacial states of the Ni/ n-Si photoanodes were efficiently diminished through a rapid thermal process (RTP). Calculated from the Mott-Schottky plots, the Schottky barrier height of Ni/ n-Si was increased from 0.58 to 0.78 eV after RTP. Under the illumination of 100 mW cm -2 of the Xe lamp, the onset potential of the Ni/ n-Si photoanode for water oxidation was negatively shifted for 150 mV after RTP. Besides, the RTP-treated Ni/ n-Si photoanode exhibited a high stability during the PEC water oxidation of 8 h in 1 M KOH solution.

  18. Natural printed silk substrate circuit fabricated via surface modification using one step thermal transfer and reduction graphene oxide

    Science.gov (United States)

    Cao, Jiliang; Huang, Zhan; Wang, Chaoxia

    2018-05-01

    Graphene conductive silk substrate is a preferred material because of its biocompatibility, flexibility and comfort. A flexible natural printed silk substrate circuit was fabricated by one step transfer of graphene oxide (GO) paste from transfer paper to the surface of silk fabric and reduction of the GO to reduced graphene oxide (RGO) using a simple hot press treatment. The GO paste was obtained through ultrasonic stirring exfoliation under low temperature, and presented excellent printing rheological properties at high concentration. The silk fabric was obtained a surface electric resistance as low as 12.15 KΩ cm-1, in the concentration of GO 50 g L-1 and hot press at 220 °C for 120 s. Though the whiteness and strength decreased with the increasing of hot press temperature and time slowly, the electric conductivity of RGO surface modification silk substrate improved obviously. The surface electric resistance of RGO/silk fabrics increased from 12.15 KΩ cm-1 to 18.05 KΩ cm-1, 28.54 KΩ cm-1 and 32.53 KΩ cm-1 after 10, 20 and 30 washing cycles, respectively. The results showed that the printed silk substrate circuit has excellent washability. This process requires no chemical reductant, and the reduction efficiency and reduction degree of GO is high. This time-effective and environmentally-friendly one step thermal transfer and reduction graphene oxide onto natural silk substrate method can be easily used to production of reduced graphene oxide (RGO) based flexible printed circuit.

  19. Effect of thermal processing on silver thin films of varying thickness deposited on zinc oxide and indium tin oxide

    International Nuclear Information System (INIS)

    Sivaramakrishnan, K.; Ngo, A. T.; Alford, T. L.; Iyer, S.

    2009-01-01

    Silver films of varying thicknesses (25, 45, and 60 nm) were deposited on indium tin oxide (ITO) on silicon and zinc oxide (ZnO) on silicon. The films were annealed in vacuum for 1 h at different temperatures (300-650 deg. C). Four-point-probe measurements were used to determine the resistivity of the films. All films showed an abrupt change in resistivity beyond an onset temperature that varied with thickness. Rutherford backscattering spectrometry measurements revealed agglomeration of the Ag films upon annealing as being responsible for the resistivity change. X-ray pole figure analysis determined that the annealed films took on a preferential texturing; however, the degree of texturing was significantly higher in Ag/ZnO/Si than in Ag/ITO/Si samples. This observation was accounted for by interface energy minimization. Atomic force microscopy (AFM) measurements revealed an increasing surface roughness of the annealed films with temperature. The resistivity behavior was explained by the counterbalancing effects of increasing crystallinity and surface roughness. Average surface roughness obtained from the AFM measurements were also used to model the agglomeration of Ag based on Ostwald ripening theory

  20. Ion beam analysis of the dry thermal oxidation of thin polycrystalline SiGe films

    International Nuclear Information System (INIS)

    Kling, A.; Soares, J.C.; Prieto, A.C.; Jimenez, J.; Rodriguez, A.; Sangrador, J.; Rodriguez, T.

    2005-01-01

    Nanoparticles of Ge embedded in a formed dielectric matrix appear as very promising systems for electronic and photonic applications. We present here an exhaustive characterization of the oxidation process of polycrystalline SiGe layers from the starting of its oxidation process to the total oxidation of it. We have characterized the process by RBS, FTIR and Raman spectroscopy, showing the necessity to use different techniques in order to get a full view of the process. First the Si-Si and Si-Ge bonds are oxidized growing SiO 2 , and Ge segregates from the SiO 2 . As soon as all Si is oxidized GeO 2 is growing gradually. RBS has demonstrated to be very useful to characterize the SiO 2 and the remaining non-oxidized poly-SiGe layer thickness, as well as for the determination of the Ge fraction, where the high sensitivity of this technique allows to explore its whole range. On the other hand, for the reliable determination of the GeO 2 thickness, information on the amount of Ge-O bonding had to be obtained from FTIR spectra. Raman spectroscopy yields detailed information about the oxidation processes for different bonds (Si-Si, Si-Ge, Ge-Ge)

  1. Preparation and thermal properties of form-stable palmitic acid/active aluminum oxide composites as phase change materials for latent heat storage

    International Nuclear Information System (INIS)

    Fang, Guiyin; Li, Hui; Cao, Lei; Shan, Feng

    2012-01-01

    Form-stable palmitic acid (PA)/active aluminum oxide composites as phase change materials were prepared by adsorbing liquid palmitic acid into active aluminum oxide. In the composites, the palmitic acid was used as latent heat storage materials, and the active aluminum oxide was used as supporting material. Fourier transformation infrared spectroscope (FT-IR), X-ray diffractometer (XRD) and scanning electronic microscope (SEM) were used to determine the chemical structure, crystalloid phase and microstructure of the composites, respectively. The thermal properties and thermal stability were investigated by a differential scanning calorimeter (DSC) and a thermogravimetry analyzer (TGA). The FT-IR analyses results indicated that there is no chemical interaction between the palmitic acid and active aluminum oxide. The SEM results showed that the palmitic acid was well adsorbed into porous network of the active aluminum oxide. The DSC results indicated that the composites melt at 60.25 °C with a latent heat of 84.48 kJ kg −1 and solidify at 56.86 °C with a latent heat of 78.79 kJ kg −1 when the mass ratio of the PA to active aluminum oxide is 0.9:1. Compared with that of the PA, the melting and solidifying time of the composites CPCM5 was reduced by 20.6% and 21.4% because of the increased heat transfer rate through EG addition. The TGA results showed that the active aluminum oxide can improve the thermal stability of the composites. -- Highlights: ► Form-stable PA/active aluminum oxide composites as PCMs were prepared. ► Chemical structure, crystalloid phase and microstructure of composites were determined. ► Thermal properties and thermal stability of the composites were investigated. ► Expanded graphite can improve thermal conductivity of the composites.

  2. Antibacterial characteristics of thermal plasma spray system.

    Science.gov (United States)

    Goudarzi, M; Saviz, Sh; Ghoranneviss, M; Salar Elahi, A

    2018-03-15

    The objective of this study is to investigate antibacterial characteristics of a thermal plasma spray system. For this purpose, copper powder was coated on a handmade atmospheric plasma spraying system made by the stainless steel 316 substrate, which is preheated at different temperatures before spraying. A number of deposition characteristics such as antibacterial characteristics, adhesion strength and hardness of coating, was investigated. All of the spray parameters are fixed except the substrate temperature. The chemical composition was analyzed by X-ray diffraction (XRD). A scanning electron microscopy (SEM) and back scattering electron microscopy (BSE) were used to show the coating microstructure, its thickness and also the powder micrograph. The energy dispersive X-ray spectroscopy (EDX) was used to analyze the coating particles. Hardness of the deposition was examined by Vickers tester (HV0.1). Its adhesion strength was declared by cross cut tester (TQC). In addition, the percentage of bactericidal coating was evidenced with Staphylococcus aurous and Escherichia coli bacteria. Study results show that as the substrates temperature increases, the number of splats in the shape of pancake increases, the greatness and percentage of the deposition porosity both decrease. The increment of the substrate temperature leads to more oxidation and makes thicker dendrites on the splat. The enhancement of the substrate temperature also enlarges thickness and efficiency of coating. The interesting results are that antibacterial properties of coatings against the Escherichia coli are more than Staphylococcus aurous bacteria. However the bactericidal percentage of the coatings against Staphylococcus aurous and Escherichia coli bacteria roughly does not change with increasing the substrate temperature. Furthermore, by increment of the substrate temperature, coatings with both high adhesion and hardness are obtained. Accordingly, the temperature of substrate can be an

  3. Fabrication and Optoelectrical Properties of IZO/Cu2O Heterostructure Solar Cells by Thermal Oxidation

    Directory of Open Access Journals (Sweden)

    Cheng-Chiang Chen

    2012-01-01

    Full Text Available Indium zinc oxide (IZO/cupper oxide (Cu2O is a nontoxic nature and an attractive all-oxide candidate for low-cost photovoltaic (PV applications. The present paper reports on the fabrication of IZO/Cu2O heterostructure solar cells which the Cu2O layers were prepared by oxidation of Cu thin films deposited on glass substrate. The measured parameters of cells were the short-circuit current (Isc, the open-circuit voltage (Voc, the maximum output power (Pm, the fill factor (FF, and the efficiency (η, which had values of 0.11 mA, 0.136 V, 5.05 μW, 0.338, and 0.56%, respectively, under AM 1.5 illumination.

  4. Thermal and Physical Properties of Plutonium Dioxide Produced from the Oxidation of Metal: a Data Summary

    Energy Technology Data Exchange (ETDEWEB)

    Wayne, David M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-01-13

    The ARIES Program at the Los Alamos National Laboratory removes plutonium metal from decommissioned nuclear weapons, and converts it to plutonium dioxide in a specially-designed Direct Metal Oxidation furnace. The plutonium dioxide is analyzed for specific surface area, particle size distribution, and moisture content. The purpose of these analyses is to certify that the plutonium dioxide powder meets or exceeds the specifications of the end-user, and the specifications for the packaging and transport of nuclear materials. Analytical results from plutonium dioxide from ARIES development activities, from ARIES production activities, from muffle furnace oxidation of metal, and from metal that was oxidized over a lengthy time interval in air at room temperature, are presented. The processes studied produce plutonium dioxide powder with distinct differences in measured properties, indicating the significant influence of oxidation conditions on physical properties.

  5. Water absorption in thermally grown oxides on SiC and Si: Bulk oxide and interface properties

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Gang [Institute for Advanced Materials, Devices and Nanotechnology, Rutgers University, Piscataway, New Jersey 08854 (United States); Xu, Can; Feldman, Leonard C. [Institute for Advanced Materials, Devices and Nanotechnology, Rutgers University, Piscataway, New Jersey 08854 (United States); Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854 (United States); Yakshinskiy, Boris; Wielunski, Leszek; Gustafsson, Torgny [Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854 (United States); Bloch, Joseph [Institute for Advanced Materials, Devices and Nanotechnology, Rutgers University, Piscataway, New Jersey 08854 (United States); NRCN, Beer-Sheva 84190 (Israel); Dhar, Sarit [Department of Physics, Auburn University, Auburn, Alabama 36849 (United States)

    2014-11-10

    We combine nuclear reaction analysis and electrical measurements to study the effect of water exposure (D{sub 2}O) on the n-type 4H-SiC carbon face (0001{sup ¯}) MOS system and to compare to standard silicon based structures. We find that: (1) The bulk of the oxides on Si and SiC behave essentially the same with respect to deuterium accumulation; (2) there is a significant difference in accumulation of deuterium at the semiconductor/dielectric interface, the SiC C-face structure absorbs an order of magnitude more D than pure Si; (3) standard interface passivation schemes such as NO annealing greatly reduce the interfacial D accumulation; and (4) the effective interfacial charge after D{sub 2}O exposure is proportional to the total D amount at the interface.

  6. Magnetic, thermal and luminescence properties in room-temperature nanosecond electron-irradiated various metal oxide nanopowders

    Science.gov (United States)

    Sokovnin, S. Yu; Balezin, M. E.; Il’ves, V. G.

    2018-03-01

    By means of pulsed electron beam evaporation in vacuum of targets non-magnetic, in bulk state, Al2O3 and YSZ (ZrO2-8% Y2O3) oxides, magnetic nanopowders (NPs) with a high specific surface were produced. The NPs were subsequently irradiated in air by electrons with energy of 700 keV, using a URT-1 accelerator for 15 and 30 minutes. The magnetic, thermal, and pulsed cathodoluminescence (PCL) characteristics of NPs were measured before and after irradiation. It was established that the electron irradiation non-monotonically changes the magnetization of the pristine samples. To the contrary, a clear correlation between the intensity of PCL and the irradiation doses is found in the oxides. There was a decrease in the intensity of PCL after irradiation. Luminescent and thermal properties reflect the transformation of structural defects in NPs more strongly after the exposure to a pulsed electron beam in comparison with corresponding changes of the NPs magnetic response.

  7. Adaptation, validation and application of the chemo-thermal oxidation method to quantify black carbon in soils

    International Nuclear Information System (INIS)

    Agarwal, Tripti; Bucheli, Thomas D.

    2011-01-01

    The chemo-thermal oxidation method at 375 o C (CTO-375) has been widely used to quantify black carbon (BC) in sediments. In the present study, CTO-375 was tested and adapted for application to soil, accounting for some matrix specific properties like high organic carbon (≤39%) and carbonate (≤37%) content. Average recoveries of standard reference material SRM-2975 ranged from 25 to 86% for nine representative Swiss and Indian samples, which is similar to literature data for sediments. The adapted method was applied to selected samples of the Swiss soil monitoring network (NABO). BC content exhibited different patterns in three soil profiles while contribution of BC to TOC was found maximum below the topsoil at all three sites, however at different depths (60-130 cm). Six different NABO sites exhibited largely constant BC concentrations over the last 25 years, with short-term (6 months) prevailing over long-term (5 years) temporal fluctuations. - Research highlights: → The CTO-375 method was adapted and validated for BC analysis in soils. → Method validation figures of merit proofed satisfactory. → Application is shown with soil cores and topsoil temporal variability. → BC content can be elevated in subsurface soils. → BC contents in surface soils were largely constant over the last 25 years. - Although widely used also for soils, the chemo-thermal oxidation method at 375 o C to quantify black carbon has never been properly validated for this matrix before.

  8. Activation of sputter-processed indium–gallium–zinc oxide films by simultaneous ultraviolet and thermal treatments

    Science.gov (United States)

    Tak, Young Jun; Du Ahn, Byung; Park, Sung Pyo; Kim, Si Joon; Song, Ae Ran; Chung, Kwun-Bum; Kim, Hyun Jae

    2016-01-01

    Indium–gallium–zinc oxide (IGZO) films, deposited by sputtering at room temperature, still require activation to achieve satisfactory semiconductor characteristics. Thermal treatment is typically carried out at temperatures above 300 °C. Here, we propose activating sputter- processed IGZO films using simultaneous ultraviolet and thermal (SUT) treatments to decrease the required temperature and enhance their electrical characteristics and stability. SUT treatment effectively decreased the amount of carbon residues and the number of defect sites related to oxygen vacancies and increased the number of metal oxide (M–O) bonds through the decomposition-rearrangement of M–O bonds and oxygen radicals. Activation of IGZO TFTs using the SUT treatment reduced the processing temperature to 150 °C and improved various electrical performance metrics including mobility, on-off ratio, and threshold voltage shift (positive bias stress for 10,000 s) from 3.23 to 15.81 cm2/Vs, 3.96 × 107 to 1.03 × 108, and 11.2 to 7.2 V, respectively. PMID:26902863

  9. Activation of sputter-processed indium-gallium-zinc oxide films by simultaneous ultraviolet and thermal treatments.

    Science.gov (United States)

    Tak, Young Jun; Ahn, Byung Du; Park, Sung Pyo; Kim, Si Joon; Song, Ae Ran; Chung, Kwun-Bum; Kim, Hyun Jae

    2016-02-23

    Indium-gallium-zinc oxide (IGZO) films, deposited by sputtering at room temperature, still require activation to achieve satisfactory semiconductor characteristics. Thermal treatment is typically carried out at temperatures above 300 °C. Here, we propose activating sputter- processed IGZO films using simultaneous ultraviolet and thermal (SUT) treatments to decrease the required temperature and enhance their electrical characteristics and stability. SUT treatment effectively decreased the amount of carbon residues and the number of defect sites related to oxygen vacancies and increased the number of metal oxide (M-O) bonds through the decomposition-rearrangement of M-O bonds and oxygen radicals. Activation of IGZO TFTs using the SUT treatment reduced the processing temperature to 150 °C and improved various electrical performance metrics including mobility, on-off ratio, and threshold voltage shift (positive bias stress for 10,000 s) from 3.23 to 15.81 cm(2)/Vs, 3.96 × 10(7) to 1.03 × 10(8), and 11.2 to 7.2 V, respectively.

  10. Characteristics of hydrogen produced by partial oxidation and auto-thermal reforming in a small methanol reformer

    Science.gov (United States)

    Horng, Rong-Fang; Chou, Huann-Ming; Lee, Chiou-Hwang; Tsai, Hsien-Te

    This paper investigates experimentally, the transient characteristics of a small methanol reformer using partial oxidation (POX) and auto-thermal reforming (ATR) for fuel cell applications. The parameters varied were heating temperature, methanol supply rate, steady mode shifting temperature, O 2/C (O 2/CH 3OH) and S/C (H 2O/CH 3OH) molar ratios with the main aim of promoting a rapid response and a high flow rate of hydrogen. The experiments showed that a high steady mode shifting temperature resulted in a faster temperature rise at the catalyst outlet and vice versa and that a low steady mode shifting temperature resulted in a lower final hydrogen concentration. However, when the mode shifting temperature was too high, the hydrogen production response was not necessarily improved. It was subsequently shown that the optimum steady mode shifting temperature for this experimental set-up was approximately 75 °C. Further, the hydrogen concentration produced by the auto-thermal process was as high as 49.12% and the volume flow rate up to 23.0 L min -1 compared to 40.0% and 20.5 L min -1 produced by partial oxidation.

  11. Final Report: Fiscal Year 1997 demonstration of omnivorous non-thermal mixed waste treatment: Direct chemical oxidation of organic solids and liquids using peroxydisulfate

    International Nuclear Information System (INIS)

    Cooper, J.F.; Ballazs G.B.

    1998-01-01

    Direct Chemical Oxidation (DCO) is a non-thermal, ambient pressure, aqueous-based technology for the oxidative destruction of the organic components of hazardous or mixed waste streams. The process has been developed for applications in waste treatment, chemical demilitarization and decontamination at LLNL since 1992. The process uses solutions of the peroxydisulfate ion (typically sodium or ammonium salts) to completely mineralize the organics to carbon dioxide and water. The expended oxidant may be electrolytically regenerated to minimize secondary waste. The paper briefly describes: free radical and secondary oxidant formation; electrochemical regeneration; offgas stream; and throughput

  12. Final Report: Fiscal Year 1997 demonstration of omnivorous non-thermal mixed waste treatment: Direct chemical oxidation of organic solids and liquids using peroxydisulfate

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, J.F.

    1998-01-01

    Direct Chemical Oxidation (DCO) is a non-thermal, ambient pressure, aqueous-based technology for the oxidative destruction of the organic components of hazardous or mixed waste streams. The process has been developed for applications in waste treatment, chemical demilitarization and decontamination at LLNL since 1992. The process uses solutions of the peroxydisulfate ion (typically sodium or ammonium salts) to completely mineralize the organics to carbon dioxide and water. The expended oxidant may be electrolytically regenerated to minimize secondary waste. The paper briefly describes: free radical and secondary oxidant formation; electrochemical regeneration; offgas stream; and throughput.

  13. Advanced oxidation technology for H2S odor gas using non-thermal plasma

    Science.gov (United States)

    Tao, ZHU; Ruonan, WANG; Wenjing, BIAN; Yang, CHEN; Weidong, JING

    2018-05-01

    Non-thermal plasma technology is a new type of odor treatment processing. We deal with H2S from waste gas emission using non-thermal plasma generated by dielectric barrier discharge. On the basis of two criteria, removal efficiency and absolute removal amount, we deeply investigate the changes in electrical parameters and process parameters, and the reaction process of the influence of ozone on H2S gas removal. The experimental results show that H2S removal efficiency is proportional to the voltage, frequency, power, residence time and energy efficiency, while it is inversely proportional to the initial concentration of H2S gas, and ozone concentration. This study lays the foundations of non-thermal plasma technology for further commercial application.

  14. Isochoric thermal conductivity of solid carbon oxide: the role of phonons and 'diffusive' modes

    International Nuclear Information System (INIS)

    Konstantinov, V A; Manzhelii, V G; Revyakin, V P; Sagan, V V; Pursky, O I

    2006-01-01

    The isochoric thermal conductivity of solid CO was investigated in three samples of different densities in the interval from 35 K to the onset of melting. In α-CO the temperature dependence of the isochoric thermal conductivity is significantly weaker than Λ∝1/T; in β-CO it increases slightly with temperature. A quantitative description of the experimental results is given within the Debye model of thermal conductivity in the approximation of the corresponding relaxation times and which allows for the fact that the mean-free path of phonons cannot become smaller than half the phonon wavelength. On this consideration the heat is transported by both phonons and 'diffusive' modes

  15. Characterization of thermal reaction of aluminum/copper (II) oxide/poly(tetrafluoroethene) nanocomposite by thermogravimetric analysis, differential scanning calorimetry, mass spectrometry and X-ray diffraction

    International Nuclear Information System (INIS)

    Li, Xiangyu; Yang, Hongtao; Li, Yan-chun

    2015-01-01

    Highlights: • The thermal reaction properties of the Al/CuO/PTFE nanocomposite were investigated. • The Al/PTFE and CuO/PTFE nanocomposites were prepared and tested for comparison. • TG/DSC–MS and XRD analysis were performed. • PTFE is oxidizing Al and reducing CuO during the thermal decomposition. - Abstract: The application of fluoropolymers as reactive agent in energetic materials have attracted significant interest recently. In this study, the thermal reaction properties of the aluminum nanoparticles/copper (II) oxide nanoparticles/poly(tetrafluoroethene) (Al-NPs/CuO-NPs/PTFE) nanocomposite (mass ratio of Al-NPs/CuO-NPs/PTFE = 20/60/20) were investigated by means of thermogravimetry/differential scanning calorimetry–mass spectrometry (TG/DSC–MS) and X-ray diffraction (XRD) analyses. The Al-NPs/PTFE (mass ratio of Al-NPs/PTFE = 50/50) and CuO-NPs/PTFE (mass ratio of CuO-NPs/PTFE = 75/25) nanocomposites were also prepared and tested for comparison. It is observed that PTFE is acting as both oxidizer and reducer during the thermal decomposition process of Al-NPs/CuO-NPs/PTFE nanocomposites. Before 615 °C, PTFE is oxidized by CuO-NPs and oxidizing Al-NPs, resulting mass reduction. After 615 °C, the excessive aluminum and copper (I)/copper (II) oxide will proceed the exothermic condensed phase reaction.

  16. Thermal analysis as an aid to forensics: Alkane melting and oxidative stability of wool

    International Nuclear Information System (INIS)

    Alan Riga, D.

    1998-01-01

    Interdisciplinary methods and thermal analytical techniques in particular are effective tools in aiding the identification and characterization of materials in question involved in civil or criminal law. Forensic material science uses systematic knowledge of the physical or material world gained through analysis, observation and experimentation. Thermal analytical data can be used to aid the legal system in interpreting technical variations in quite often a complex system.Calorimetry and thermal microscopic methods helped define a commercial product composed of alkanes that was involved in a major law suit. The solid-state structures of a number of normal alkanes have unique crystal structures. These alkanes melt and freeze below room temperature to more than 60C below zero. Mixtures of specific alkanes have attributes of pure chemicals. The X-ray diffraction structure of a mixture of alkanes is the same as a pure alkane, but the melting and freezing temperature are significantly lower than predicted. The jury ruled that the product containing n-alkanes had the appropriate melting characteristics. The thermal-physical properties made a commercial fluid truly unique and there was no advertising infringement according to the law and the jury trialA combination of thermogravimetry, differential thermal analysis, infrared spectroscopy and macrophotography were used to conduct an extensive modeling and analysis of physical evidence obtained in a mobile home fire and explosion. A person's death was allegedly linked to the misuse of a kerosene space heater. The thermal analytical techniques showed that external heating was the cause of the space heater's deformation, not a firing of the heater with gasoline and kerosene. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  17. Thermal analysis as an aid to forensics: Alkane melting and oxidative stability of wool

    Energy Technology Data Exchange (ETDEWEB)

    Alan Riga, D. [Professor of Chemistry, Cleveland State University and TechCon Inc., 6325 Aldenham Dr., Cleveland, OH 44143-3331 (United States)

    1998-12-21

    Interdisciplinary methods and thermal analytical techniques in particular are effective tools in aiding the identification and characterization of materials in question involved in civil or criminal law. Forensic material science uses systematic knowledge of the physical or material world gained through analysis, observation and experimentation. Thermal analytical data can be used to aid the legal system in interpreting technical variations in quite often a complex system.Calorimetry and thermal microscopic methods helped define a commercial product composed of alkanes that was involved in a major law suit. The solid-state structures of a number of normal alkanes have unique crystal structures. These alkanes melt and freeze below room temperature to more than 60C below zero. Mixtures of specific alkanes have attributes of pure chemicals. The X-ray diffraction structure of a mixture of alkanes is the same as a pure alkane, but the melting and freezing temperature are significantly lower than predicted. The jury ruled that the product containing n-alkanes had the appropriate melting characteristics. The thermal-physical properties made a commercial fluid truly unique and there was no advertising infringement according to the law and the jury trialA combination of thermogravimetry, differential thermal analysis, infrared spectroscopy and macrophotography were used to conduct an extensive modeling and analysis of physical evidence obtained in a mobile home fire and explosion. A person's death was allegedly linked to the misuse of a kerosene space heater. The thermal analytical techniques showed that external heating was the cause of the space heater's deformation, not a firing of the heater with gasoline and kerosene. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  18. Investigation of Molecular Structure and Thermal Properties of Thermo-Oxidative Aged SBS in Blends and Their Relations.

    Science.gov (United States)

    Xu, Xiong; Yu, Jianying; Xue, Lihui; Zhang, Canlin; Zha, Yagang; Gu, Yi

    2017-07-07

    Tri-block copolymer styrene-butadiene (SBS) is extensively applied in bituminous highway construction due to its high elasticity and excellent weather resistance. With the extension of time, tri-block structural SBS automatically degrades into bi-block structural SB- with some terminal oxygen-containing groups under the comprehensive effects of light, heat, oxygen, etc. In this paper, the effects of aging temperature, aging time and oxygen concentration on the molecular structure of thermo-oxidative aged SBS were mainly investigated using Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS), and the correlation between oxygen-containing groups and thermal properties (TG-DTG) was further discussed. The FTIR and XPS results show that rapid decomposition of SBS will occur with increments of aging temperature, aging time and oxygen concentration, and a large number of oxygen-containing groups such as -OH, C=O, -COOH, etc. will be formed during thermo-oxidative aging. In short-term aging, changes in aging temperature and oxygen concentration have a significant impact on the structural damage of SBS. However, in long-term aging, it has no further effect on the molecular structure of SBS or on increasing oxygen concentration. The TG and DTG results indicate that the concentration of substances with low molecular weight gradually increases with the improvement of the degree of aging of the SBS, while the initial decomposition rate increases at the beginning of thermal weightlessness and the decomposition rate slows down in comparison with neat SBS. From the relation between the XPS and TG results, it can be seen that the initial thermal stability of SBS rapidly reduces as the relative concentration of the oxygen-containing groups accumulates around 3%, while the maximum decomposition temperature slowly decreases when the relative concentration of the oxygen-containing groups is more than 3%, due to the difficult damage to strong bonds

  19. Investigation on Synthesis, Stability, and Thermal Conductivity Properties of Water-Based SnO2/Reduced Graphene Oxide Nanofluids

    Science.gov (United States)

    Yu, Xiaofen; Wu, Qibai; Zhang, Haiyan; Zeng, Guoxun; Li, Wenwu; Qian, Yannan; Li, Yang; Yang, Guoqiang; Chen, Muyu

    2017-01-01

    With the rapid development of industry, heat removal and management is a major concern for any technology. Heat transfer plays a critically important role in many sectors of engineering; nowadays utilizing nanofluids is one of the relatively optimized techniques to enhance heat transfer. In the present work, a facile low-temperature solvothermal method was employed to fabricate the SnO2/reduced graphene oxide (rGO) nanocomposite. X-ray diffraction (XRD), thermogravimetric analysis (TGA), X-ray photoelectron spectroscope (XPS), Raman spectroscopy, and transmission electron microscopy (TEM) have been performed to characterize the SnO2/rGO nanocomposite. Numerous ultrasmall SnO2 nanoparticles with average diameters of 3–5 nm were anchored on the surface of rGO, which contain partial hydrophilic functional groups. Water-based SnO2/rGO nanofluids were prepared with various weight concentrations by using an ultrasonic probe without adding any surfactants. The zeta potential was measured to investigate the stability of the as-prepared nanofluid which exhibited great dispersion stability after quiescence for 60 days. A thermal properties analyzer was employed to measure thermal conductivity of water-based SnO2/rGO nanofluids, and the results showed that the enhancement of thermal conductivity could reach up to 31% at 60 °C under the mass fraction of 0.1 wt %, compared to deionized water. PMID:29280972

  20. Enhanced mechanical, thermal and antimicrobial properties of poly(vinyl alcohol)/graphene oxide/starch/silver nanocomposites films.

    Science.gov (United States)

    Usman, Adil; Hussain, Zakir; Riaz, Asim; Khan, Ahmad Nawaz

    2016-11-20

    In the present work, synthesis of poly(vinyl alcohol)/graphene oxide/starch/silver (PVA/GO/Starch/Ag) nanocomposites films is reported. Such films have been characterized and investigated for their mechanical, thermal and antimicrobial properties. The exfoliation of GO in the PVA matrix occurs owing to the non-covalent interactions of the polymer chains of PVA and hydrophilic surface of the GO layers. Presence of GO in PVA and PVA/starch blends were found to enhance the tensile strength of the nanocomposites system. It was found that the thermal stability of PVA as well as PVA/starch blend systems increased by the incorporation of GO where strong physical bonding between GO layers and PVA/starch blends is assumed to cause thermal barrier effects. Antimicrobial properties of the prepared films were investigated against Escherichia coli and Staphylococcus aureus. Our results show enhanced antimicrobial properties of the prepared films where PVA-GO, PVA-Ag, PVA-GO-Ag and PVA-GO-Ag-Starch showed antimicrobial activity in ascending order. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Fabrication of polylactic acid/hydroxyapatite/graphene oxide composite and their thermal stability, hydrophobic and mechanical properties

    Directory of Open Access Journals (Sweden)

    Ming Gong

    2017-06-01

    Full Text Available A series of polylactic acid/hydroxyapatite/graphene oxide composite (PLA/HA/GO were fabricated via solution blending and casting method using N,N-dimethyl-formamide (DMF and CH2Cl2 as mutual solvents. The physicochemical properties of the resulting composites were characterized by means of FT-IR, SEM, TEM, Raman spectra, XRD and N2-physisorption. Particularly, the thermal stabilities, hydrophobic and mechanical properties of PLA/HA/GO composites were systematically investigated. The influences of GO content on thermal stabilities, hydrophobic and mechanical properties of the composites were also evaluated. The results showed that the addition of GO and HA not only improved the thermal stability of PLA, but also improved the hydrophobic property of PLA-based composites. By compared with the PLA/HA/GO composite, the tensile strength of pristine PLA is slight high. The tensile strength and hardness of PLA/HA/GO composites increased with the increase of GO content. The obtained PLA/HA/GO composite may be a promising material for load-bearing orthopedic implants.

  2. The modeling and simulation of thermal based modified solid oxide fuel cell (SOFC for grid-connected systems

    Directory of Open Access Journals (Sweden)

    Ayetül Gelen

    2015-05-01

    Full Text Available This paper presents a thermal based modified dynamic model of a Solid Oxide Fuel Cell (SOFC for grid-connected systems. The proposed fuel cell model involves ohmic, activation and concentration voltage losses, thermal dynamics, methanol reformer, fuel utilization factor and power limiting module. A power conditioning unit (PCU, which consists of a DC-DC boost converter and a DC-AC voltage-source inverter (VSI, their controller, transformer and filter, is designed for grid-connected systems. The voltage-source inverter with six Insulated Gate Bipolar Transistor (IGBT switches inverts the DC voltage that comes from the converter into a sinusoidal voltage synchronized with the grid. The simulations and modeling of the system are developed on Matlab/Simulink environment. The performance of SOFC with converter is examined under step and random load conditions. The simulation results show that the designed boost converter for the proposed thermal based modified SOFC model has fairly followed different DC load variations. Finally, the AC bus of 400 Volt and 50 Hz is connected to a single-machine infinite bus (SMIB through a transmission line. The real and reactive power managements of the inverter are analyzed by an infinite bus system. Thus, the desired nominal values are properly obtained by means of the inverter controller.

  3. A lumped model of venting during thermal runaway in a cylindrical Lithium Cobalt Oxide lithium-ion cell

    Science.gov (United States)

    Coman, Paul T.; Rayman, Sean; White, Ralph E.

    2016-03-01

    This paper presents a mathematical model built for analyzing the intricate thermal behavior of a 18650 LCO (Lithium Cobalt Oxide) battery cell during thermal runaway when venting of the electrolyte and contents of the jelly roll (ejecta) is considered. The model consists of different ODEs (Ordinary Differential Equations) describing reaction rates and electrochemical reactions, as well as the isentropic flow equations for describing electrolyte venting. The results are validated against experimental findings from Golubkov et al. [1] [Andrey W. Golubkov, David Fuchs, Julian Wagner, Helmar Wiltsche, Christoph Stangl, Gisela Fauler, Gernot Voitice Alexander Thaler and Viktor Hacker, RSC Advances, 4:3633-3642, 2014] for two cases - with flow and without flow. The results show that if the isentropic flow equations are not included in the model, the thermal runaway is triggered prematurely at the point where venting should occur. This shows that the heat dissipation due to ejection of electrolyte and jelly roll contents has a significant contribution. When the flow equations are included, the model shows good agreement with the experiment and therefore proving the importance of including venting.

  4. Investigation on Synthesis, Stability, and Thermal Conductivity Properties of Water-Based SnO2/Reduced Graphene Oxide Nanofluids

    Directory of Open Access Journals (Sweden)

    Xiaofen Yu

    2017-12-01

    Full Text Available With the rapid development of industry, heat removal and management is a major concern for any technology. Heat transfer plays a critically important role in many sectors of engineering; nowadays utilizing nanofluids is one of the relatively optimized techniques to enhance heat transfer. In the present work, a facile low-temperature solvothermal method was employed to fabricate the SnO2/reduced graphene oxide (rGO nanocomposite. X-ray diffraction (XRD, thermogravimetric analysis (TGA, X-ray photoelectron spectroscope (XPS, Raman spectroscopy, and transmission electron microscopy (TEM have been performed to characterize the SnO2/rGO nanocomposite. Numerous ultrasmall SnO2 nanoparticles with average diameters of 3–5 nm were anchored on the surface of rGO, which contain partial hydrophilic functional groups. Water-based SnO2/rGO nanofluids were prepared with various weight concentrations by using an ultrasonic probe without adding any surfactants. The zeta potential was measured to investigate the stability of the as-prepared nanofluid which exhibited great dispersion stability after quiescence for 60 days. A thermal properties analyzer was employed to measure thermal conductivity of water-based SnO2/rGO nanofluids, and the results showed that the enhancement of thermal conductivity could reach up to 31% at 60 °C under the mass fraction of 0.1 wt %, compared to deionized water.

  5. Surfactant controlled low-temperature thermal decomposition route to zinc oxide nanorods from zinc(II) acetylacetonate monohydrate

    Energy Technology Data Exchange (ETDEWEB)

    Purkayastha, Debraj Dhar; Sarma, Bedabrat; Bhattacharjee, Chira R., E-mail: crbhattacharjee@rediffmail.com

    2014-10-15

    Zinc oxide (ZnO) nanorods were synthesized via a low-temperature thermal decomposition of zinc(II) acetylacetonate monohydrate, [Zn(C{sub 5}H{sub 7}O{sub 2}){sub 2}].H{sub 2}O. A relatively inexpensive surfactant, octadecylamine (C{sub 18}H{sub 37}NH{sub 2}) served both as a reaction solvent and a capping agent during the synthesis of ZnO nanorods. The synthesized nanorods were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), FT-IR, UV–visible, and photoluminescence (PL) studies. The XRD spectrum furnished evidence for the hexagonal wurtzite structure of ZnO. TEM images revealed the material to be rod shaped having diameter 30 nm and length 200 nm. The HRTEM image showed that the lattice fringes between the two adjacent planes are 0.244 nm apart, which corresponds to the interplanar separation of the (1 0 1) plane of hexagonal ZnO. The electron diffraction (ED) pattern confirmed the single crystalline nature of the nanorods. The PL spectrum showed two UV emissions at 356 nm (∼3.48 eV) and 382 nm (∼3.25 eV). ZnO nanorods also showed very weak blue bands at 445, 453 and 470 nm. - Highlights: Low temperature thermal decomposition of zinc(II) acetylacetonate monohydrate gave zinc oxide nanorods. Powder XRD showed hexagonal wurtzite structure of ZnO having average diameter about 24 nm. TEM images revealed the material to be of rod shape having diameter 30 nm and length 200 nm. ZnO showed band gap luminescence at 356 nm, excitonic emission at 382 nm and defect related blue bands. The synthesis is simple and can act as a paradigm for obtaining various metal oxide nanomaterials.

  6. Detection of Nonvolatile Inorganic Oxidizer-Based Explosives from Wipe Collections by Infrared Thermal Desorption-Direct Analysis in Real Time Mass Spectrometry.

    Science.gov (United States)

    Forbes, Thomas P; Sisco, Edward; Staymates, Matthew

    2018-05-07

    Infrared thermal desorption (IRTD) was coupled with direct analysis in real time mass spectrometry (DART-MS) for the detection of both inorganic and organic explosives from wipe collected samples. This platform generated discrete and rapid heating rates that allowed volatile and semivolatile organic explosives to thermally desorb at relatively lower temperatures, while still achieving elevated temperatures required to desorb nonvolatile inorganic oxidizer-based explosives. IRTD-DART-MS demonstrated the thermal desorption and detection of refractory potassium chlorate and potassium perchlorate oxidizers, compounds difficult to desorb with traditional moderate-temperature resistance-based thermal desorbers. Nanogram to sub-nanogram sensitivities were established for analysis of a range of organic and inorganic oxidizer-based explosive compounds, with further enhancement limited by the thermal properties of the most common commercial wipe materials. Detailed investigations and high-speed visualization revealed conduction from the heated glass-mica base plate as the dominant process for heating of the wipe and analyte materials, resulting in thermal desorption through boiling, aerosolization, and vaporization of samples. The thermal desorption and ionization characteristics of the IRTD-DART technique resulted in optimal sensitivity for the formation of nitrate adducts with both organic and inorganic species. The IRTD-DART-MS coupling and IRTD in general offer promising explosive detection capabilities to the defense, security, and law enforcement arenas.

  7. Thermal reduction of graphene-oxide-coated cotton for oil and organic solvent removal

    International Nuclear Information System (INIS)

    Hoai, Nguyen To; Sang, Nguyen Nhat; Hoang, Tran Dinh

    2017-01-01

    Highlights: • A new method for preparation of reduced-graphene-oxide (RGO) coated cotton is proposed. • The RGO-Cotton composites were carefully characterized using many modern techniques. • RGO-Cotton exhibited superhydrophobicity and superolephilicity. • RGO-Cotton sponges can absorb many types of oils and organic solvents and can be recycled. - Abstract: The reduced-graphene-oxide (RGO)-coated cotton sponge (RGO-Cot) was prepared by simply heating a graphene-oxide (GO)-coated cotton sponge, which was fabricated by dipping a commercial cotton sponge into a GO dispersion, under vacuum at 200 °C for 2 h. The thus prepared RGO-Cot sponges exhibited superhydrophobicity and superoleophilicity, with a water contact angle of 151°. These RGO-Cot sponges could be used for removal of many types of oils and organic solvents as they exhibit absorption capacities in the range of 22–45 times their weight and good absorption recyclability.

  8. Thermal reduction of graphene-oxide-coated cotton for oil and organic solvent removal

    Energy Technology Data Exchange (ETDEWEB)

    Hoai, Nguyen To, E-mail: hoaito@pvu.edu.vn; Sang, Nguyen Nhat; Hoang, Tran Dinh

    2017-02-15

    Highlights: • A new method for preparation of reduced-graphene-oxide (RGO) coated cotton is proposed. • The RGO-Cotton composites were carefully characterized using many modern techniques. • RGO-Cotton exhibited superhydrophobicity and superolephilicity. • RGO-Cotton sponges can absorb many types of oils and organic solvents and can be recycled. - Abstract: The reduced-graphene-oxide (RGO)-coated cotton sponge (RGO-Cot) was prepared by simply heating a graphene-oxide (GO)-coated cotton sponge, which was fabricated by dipping a commercial cotton sponge into a GO dispersion, under vacuum at 200 °C for 2 h. The thus prepared RGO-Cot sponges exhibited superhydrophobicity and superoleophilicity, with a water contact angle of 151°. These RGO-Cot sponges could be used for removal of many types of oils and organic solvents as they exhibit absorption capacities in the range of 22–45 times their weight and good absorption recyclability.

  9. Fabrication and evaluation of series-triple quantum dots by thermal oxidation of silicon nanowire

    International Nuclear Information System (INIS)

    Uchida, Takafumi; Jo, Mingyu; Tsurumaki-Fukuchi, Atsushi; Arita, Masashi; Takahashi, Yasuo; Fujiwara, Akira

    2015-01-01

    Series-connected triple quantum dots were fabricated by a simple two-step oxidation technique using the pattern-dependent oxidation of a silicon nanowire and an additional oxidation of the nanowire through the gap of the fine gates attached to the nanowire. The characteristics of multi-dot single-electron devices are obtained. The formation of each quantum dot beneath an attached gate is confirmed by analyzing the electrical characteristics and by evaluating the gate capacitances between all pairings of gates and quantum dots. Because the gate electrode is automatically attached to each dot, the device structure benefits from scalability. This technique promises integrability of multiple quantum dots with individual control gates

  10. Uranium oxide nanocrystals by microwave-assisted thermal decomposition. Electronic and structural properties

    International Nuclear Information System (INIS)

    Leduc, Jennifer; Mathur, Sanjay; Pacold, Joseph I.; Shuh, David K.; Dong, Chung-Li

    2018-01-01

    Uranium oxides have attracted much attention not only in the context of nuclear energy generation but also for their application as pristine catalysts or as supports for other (transition metal) oxides and (precious) metals. Their propensity to adopt high coordination numbers and manifest multiple oxidation states (from +II to +VI) makes them attractive candidates for catalyzed transformation reactions. Herein, we report a new synthesis route to phase-pure, crystalline UO 2 nanoparticles via microwave-assisted decomposition of a molecular uranium(IV) precursor. The electronic structure and optical absorption properties of these nanocrystals were investigated using spectroscopic methods to evaluate their suitability for photo(electro)catalytic applications. (copyright 2018 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Uranium oxide nanocrystals by microwave-assisted thermal decomposition. Electronic and structural properties

    Energy Technology Data Exchange (ETDEWEB)

    Leduc, Jennifer; Mathur, Sanjay [Institute of Inorganic Chemistry, University of Cologne (Germany); Pacold, Joseph I.; Shuh, David K. [Chemical Sciences Division, The Glenn T. Seaborg Center, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Dong, Chung-Li [Department of Physics, Tamkang University, Tamsui, Taiwan (China)

    2018-01-17

    Uranium oxides have attracted much attention not only in the context of nuclear energy generation but also for their application as pristine catalysts or as supports for other (transition metal) oxides and (precious) metals. Their propensity to adopt high coordination numbers and manifest multiple oxidation states (from +II to +VI) makes them attractive candidates for catalyzed transformation reactions. Herein, we report a new synthesis route to phase-pure, crystalline UO{sub 2} nanoparticles via microwave-assisted decomposition of a molecular uranium(IV) precursor. The electronic structure and optical absorption properties of these nanocrystals were investigated using spectroscopic methods to evaluate their suitability for photo(electro)catalytic applications. (copyright 2018 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  12. Plasmachemical synthesis and evaluation of the thermal conductivity of metal-oxide compounds "Molybdenum-uranium dioxide"

    Science.gov (United States)

    Kotelnikova, Alexandra A.; Karengin, Alexander G.; Mendoza, Orlando

    2018-03-01

    The article represents possibility to apply oxidative and reducing plasma for plasma-chemical synthesis of metal-oxide compounds «Mo‒UO2» from water-salt mixtures «molybdic acid‒uranyl nitrate» and «molybdic acid‒ uranyl acetate». The composition of water-salt mixture was calculated and the conditions ensuring plasma-chemical synthesis of «Mo‒UO2» compounds were determined. Calculations were carried out at atmospheric pressure over a wide range of temperatures (300-4000 K), with the use of various plasma coolants (air, hydrogen). The heat conductivity coefficients of metal-oxide compounds «Mo‒UO2» consisting of continuous component (molybdenum matrix) are calculated. Inclusions from ceramics in the form of uranium dioxide were ordered in the matrix. Particular attention is paid to methods for calculating the coefficients of thermal conductivity of these compounds with the use of different models. Calculated results were compared with the experimental data.

  13. Morphology, mechanical and thermal oxidative aging properties of HDPE composites reinforced by nonmetals recycled from waste printed circuit boards.

    Science.gov (United States)

    Yang, Shuangqiao; Bai, Shibing; Wang, Qi

    2016-11-01

    In this study nonmetals recycled from waste printed circuit boards (NPCB) is used as reinforce fillers in high-density polyethylene (HDPE) composites. The morphology, mechanical and thermal oxidative aging properties of NPCB reinforced HDPE composites are assessed and it compared with two other commercial functional filler for the first time. Mechanical test results showed that NPCB could be used as reinforcing fillers in the HDPE composites and mechanical properties especially for stiffness is better than other two commercial fillers. The improved mechanical property was confirmed by the higher aspect ratio and strong interfacial adhesion in scanning electron microscopy (SEM) studies. The heat deflection temperature (HDT) test showed the presence of fiberglass in NPCB can improve the heat resistance of composite for their potential applications. Meanwhile, the oxidation induction time (OIT) and the Fourier transform infrared (FTIR) spectroscopy results showed that NPCB has a near resistance to oxidation as two other commercial fillers used in this paper. The above results show the reuse of NPCB in the HDPE composites represents a promising way for resolving both the environmental pollution and the high-value reuse of resources. Copyright © 2015. Published by Elsevier Ltd.

  14. Standardization of thermal and epithermal INAA methods for simultaneous determination of U and Th in mixed oxide samples

    International Nuclear Information System (INIS)

    Acharya, R.; Pujari, P.K.; Chandra, Ruma

    2010-01-01

    Full text: Uranium and thorium are important fuel materials for nuclear power program. In recent years utilization of thoria based fuel has assumed significance due to higher energy requirements. Thorium based mixed oxide is the proposed fuel for Advanced Heavy Water Reactors (AHWR). In this respect, studies are carried out through preparation of natural U and Th mixed oxides by powder metallurgical route, wherein composition of U and Th is specific and requires strict control in terms their contents and homogeneity in the mixture. Stringent chemical quality control necessitates compositional characterization of the fuel material i.e. accurate and precise determination of U and Th. A suitable method which does not need any chemical dissolution and yields high precision results with minima sample handling is desirable. Instrumental neutron activation analysis (INAA) using reactor neutron is the technique of choice. In view of this, INAA methods namely thermal lNAA (TNAA) (utilizing whole reactor neutrons) and epithermal INAA (ENAA) (utilizing epicadmium neutrons) were standardized for the determination of U and Th in presence of each other in mixed oxide samples. In the present work pneumatic carrier facility (PCF) of Dhruva reactor and self-serve facility of CIRUS reactor were used for TNAA and ENAA respectively. Standards, synthetic samples and mixed oxide samples prepared in cellulose matrix, were irradiated for 1 minute at PCF of Dhruva reactor and for 1 hour at CIRUS reactor under cadmium cover (0.5 mm). Radioactive assay was carried out using 40% relative efficiency HPGe detector. Peak areas under the full energy peaks were evaluated by peak fit method using the PHAST software. Both activation and daughter products of U ( 239 U, 74.6 keV and 239 Np, 277 keV) and Th ( 233 Th, 86 keV and 233 Pa, 312 keV) were used for their concentration determination. The method was validated by analyzing synthetic mixed oxide samples (6-48%U-Th mixed oxide). The % deviations

  15. Thermally induced transformations of iron oxide stabilised APC residues from waste incineration

    DEFF Research Database (Denmark)

    Sørensen, Mette Abildgaard; Koch, C.B.

    2001-01-01

    Air pollution control (APC) facilities at waste incinerator plants produce large quantities of solid residues rich in salts and heavy metals. Heavy metals are readily released to water from the residues and it has, therefore, been found suitable to apply a rapid co-precipitation/adsorption process...... as a means to immobilize the toxic elements. In the 'Ferrox process', this immobilization is based on co-precipitation with an Fe(III) oxide formed by oxidation of Fe(II) by air in an aqueous slurry with the APC residue at alkaline pH. In this work we have undertaken a Mossbauer spectroscopy study of the Fe...

  16. High Temperature Oxidation of Spark Plasma Sintered and Thermally Sprayed FeAl-Based Iron Aluminides

    Czech Academy of Sciences Publication Activity Database

    Haušild, P.; Karlík, M.; Skiba, T.; Sajdl, P.; Dubský, Jiří; Palm, M.

    2012-01-01

    Roč. 122, č. 3 (2012), s. 465-468 ISSN 0587-4246. [International Symposium on Physics of Materials (ISPMA)/12./. Prague, 04.09.2011-08.09.2011] Institutional support: RVO:61389021 Keywords : thermal spraying * plasma sintering Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 0.531, year: 2012

  17. Kinetic parameters for the thermal decomposition reactions of mixed oxides of selenium and tellurium

    International Nuclear Information System (INIS)

    Jerez, A.; Castro, A.; Pico, C.; Veiga, M.L.

    1982-01-01

    A comparative study of the thermal decomposition processes of Te 3 SeO 8 and TeSeO 4 has been carried out based on the results obtained directly by a Mettler TA 3000 apparatus and from calculations using other differential and integral methods. (orig.)

  18. Thermally Annealed Iron (Oxide) Thin Film on an Alumina Barrier Layer, by XPS

    Energy Technology Data Exchange (ETDEWEB)

    Madaan, Nitesh; Kanyal, Supriya S.; Jensen, David S.; Vail, Michael A.; Dadson, Andrew; Engelhard, Mark H.; Linford, Matthew R.

    2013-09-06

    Herein we show characterization of an Fe thin film on Al_2O_3 after thermal annealing under H_2 using Al Ka X-rays. The XPS survey spectrum, narrow Fe 2p scan, and valence band regions are presented. The survey spectrum shows aluminum signals due to exposure of the underlying Al_2O_3 film during Fe nanoparticle formation.

  19. Thermally Evaporated Iron (Oxide) on an Alumina Barrier Layer, by XPS

    Energy Technology Data Exchange (ETDEWEB)

    Madaan, Nitesh; Kanyal, Supriya S.; Jensen, David S.; Vail, Michael A.; Dadson, Andrew; Engelhard, Mark H.; Linford, Matthew R.

    2013-09-06

    We report the XPS characterization of a thermally evaporated iron thin film (6 nm) deposited on an Si/SiO_2/Al_2O_3 substrate using Al Ka X-rays. An XPS survey spectrum, narrow Fe 2p scan, narrow O 1s, and valence band scan are shown.

  20. Effects of β-carotene on the thermal oxidation of fatty acids

    African Journals Online (AJOL)

    Alamzeb

    It is used in industries as food colorant and a source of vitamin A. The thermal induced ... sea buckthorn, palm and soybean oils (Puspitasari-. Nienaber et al. ... All-E-β-carotene (97.0%) was purchased from Sigma Aldrich USA, ... a local market in Graz, Austria. ... linoleic acid (53.9 %) in sunflower oil as compared to the.