WorldWideScience

Sample records for alumina scale spallation

  1. Sulfur and Moisture Effects on Alumina Scale and TBC Spallation

    Science.gov (United States)

    Smialek, James L.

    2007-01-01

    It has been well established that a few ppmw sulfur impurity may segregate to the interface of thermally grown alumina scales and the underlying substrate, resulting in bond degradation and premature spallation. This has been shown for NiAl and NiCrAl-based alloys, bare single crystal superalloys, or coated superalloys. The role of reactive elements (especially Y) has been to getter the sulfur in the bulk and preclude interfacial segregation. Pt additions are also very beneficial, however a similar thermodynamic explanation does not apply. The purpose of the present discussion is to highlight some observations of these effects on Rene'142, Rene'N5, PWA1480, and PWA1484. For PWA1480, we have mapped cyclic oxidation and spallation in terms of potential sulfur interfacial layers and found that a cumulative amount of about one monolayer is sufficient to degrade long term adhesion. Depending on substrate thickness, optimum performance occurs if sulfur is reduced below about 0.2-0.5 ppmw. This is accomplished in the laboratory by hydrogen annealing or commercially by melt-fluxing. Excellent 1150 C cyclic oxidation is thus demonstrated for desulfurized Rene'142, Rene'N5, and PWA1484. Alternatively, a series of N5 alloys provided by GE-AE have shown that as little as 15 ppmw of Y dopant was effective in providing remarkable scale adhesion. In support of a Y-S gettering mechanism, hydrogen annealing was unable to desulfurize these alloys from their initial level of 5 ppmw S. This impurity and critical doping level corresponds closely to YS or Y2S3 stoichiometry. In many cases, Y-doped alloys or alloys with marginal sulfur levels exhibit an oxidative sensitivity to the ambient humidity called Moisture-Induced Delayed Spallation (MIDS). After substantial scale growth, coupled with damage from repeated cycling, cold samples may spall after a period of time, breathing on them, or immersing them in water. While stress corrosion arguments may apply, we propose that the underlying

  2. Surface modification to prevent oxide scale spallation

    Science.gov (United States)

    Stephens, Elizabeth V; Sun, Xin; Liu, Wenning; Stevenson, Jeffry W; Surdoval, Wayne; Khaleel, Mohammad A

    2013-07-16

    A surface modification to prevent oxide scale spallation is disclosed. The surface modification includes a ferritic stainless steel substrate having a modified surface. A cross-section of the modified surface exhibits a periodic morphology. The periodic morphology does not exceed a critical buckling length, which is equivalent to the length of a wave attribute observed in the cross section periodic morphology. The modified surface can be created using at least one of the following processes: shot peening, surface blasting and surface grinding. A coating can be applied to the modified surface.

  3. HPC simulations of grain-scale spallation to improve thermal spallation drilling

    Science.gov (United States)

    Walsh, S. D.; Lomov, I.; Wideman, T. W.; Potter, J.

    2012-12-01

    Thermal spallation drilling and related hard-rock hole opening techniques are transformative technologies with the potential to dramatically reduce the costs associated with EGS well drilling and improve the productivity of new and existing wells. In contrast to conventional drilling methods that employ mechanical means to penetrate rock, thermal spallation methods fragment rock into small pieces ("spalls") without contact via the rapid transmission of heat to the rock surface. State-of-the-art constitutive models of thermal spallation employ Weibull statistical failure theory to represent the relationship between rock heterogeneity and its propensity to produce spalls when heat is applied to the rock surface. These models have been successfully used to predict such factors as penetration rate, spall-size distribution and borehole radius from drilling jet velocity and applied heat flux. A properly calibrated Weibull model would permit design optimization of thermal spallation drilling under geothermal field conditions. However, although useful for predicting system response in a given context, Weibull models are by their nature empirically derived. In the past, the parameters used in these models were carefully determined from laboratory tests, and thus model applicability was limited by experimental scope. This becomes problematic, for example, if simulating spall production at depths relevant for geothermal energy production, or modeling thermal spallation drilling in new rock types. Nevertheless, with sufficient computational resources, Weibull models could be validated in the absence of experimental data by explicit small-scale simulations that fully resolve rock grains. This presentation will discuss how high-fidelity simulations can be used to inform Weibull models of thermal spallation, and what these simulations reveal about the processes driving spallation at the grain-scale - in particular, the role that inter-grain boundaries and micro-pores play in the

  4. GRAIN-SCALE FAILURE IN THERMAL SPALLATION DRILLING

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, S C; Lomov, I; Roberts, J J

    2012-01-19

    Geothermal power promises clean, renewable, reliable and potentially widely-available energy, but is limited by high initial capital costs. New drilling technologies are required to make geothermal power financially competitive with other energy sources. One potential solution is offered by Thermal Spallation Drilling (TSD) - a novel drilling technique in which small particles (spalls) are released from the rock surface by rapid heating. While TSD has the potential to improve drilling rates of brittle granitic rocks, the coupled thermomechanical processes involved in TSD are poorly described, making system control and optimization difficult for this drilling technology. In this paper, we discuss results from a new modeling effort investigating thermal spallation drilling. In particular, we describe an explicit model that simulates the grain-scale mechanics of thermal spallation and use this model to examine existing theories concerning spalling mechanisms. We will report how borehole conditions influence spall production, and discuss implications for macro-scale models of drilling systems.

  5. Stress determination in thermally grown alumina scales using ruby luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Renusch, D.; Veal, B.W.; Koshelev, I.; Natesan, K.; Grimsditch [Argonne National Lab., IL (United States); Hou, P.Y. [Lawrence Berkeley Lab., CA (United States)

    1996-06-01

    By exploiting the strain dependence of the ruby luminescence line, we have measured the strain in alumina scales thermally grown on Fe-Cr- Al alloys. Results are compared and found to be reasonably consistent with strains determined using x rays. Oxidation studies were carried out on alloys Fe - 5Cr - 28Al and Fe - 18Cr - 10Al (at.%). Significantly different levels of strain buildup were observed in scales on these alloys. Results on similar alloys containing a ``reactive element`` (Zr or Hf) in dilute quantity are also presented. Scales on alloys containing a reactive element (RE) can support significantly higher strains than scales on RE-free alloys. With the luminescence technique, strain relief associated with spallation thresholds is readily observed.

  6. Sulfur Impurities and the Microstructure of Alumina Scales

    Science.gov (United States)

    Smialek, James L.

    1997-01-01

    The relationship between the microstructure of alumina scales, adhesion, and sulfur content was examined through a series of nickel alloys oxidized in 1100 to 1200 deg. C cyclic or isothermal exposures in air. In cyclic tests of undoped NiCrAl, adhesion was produced when the sulfur content was reduced, without any change in scale microstructure. Although interfacial voids were not observed in cyclic tests of NiCrAl, they were promoted by long-term isothermal exposures, by sulfur doping, and in most exposures of NiAl. Two single crystal superalloys, PWA 1480 and Rene' N5, were also tested, either in the as-received condition or after the sulfur content had been reduced to less than 1 ppmw by hydrogen annealing. The unannealed alloys always exhibited spalling to bare metal, but interfacial voids were not observed consistently. Desulfurized PWA 1480 and Rene' N5 exhibited remarkable adhesion and no voidage for either isothermal or cyclic exposures. The most consistent microstructural feature was that, for the cases where voids did form, the scale undersides exhibited corresponding areas with ridged oxide grain boundaries. Voids were not required for spallation nor were other microstructural features essential for adhesion. These observations are consistent with the model whereby scale spallation is controlled primarily by interfacial sulfur segregation and the consequent degradation of oxide-metal bonding.

  7. Multiple-Scale Geomechanical Models for Thermal Spallation Drilling.

    Science.gov (United States)

    Lomov, I.; Walsh, S. D.; Roberts, J. J.

    2011-12-01

    Widespread adoption of geothermal energy will require access to deeply buried geothermal sources in granitic basement rocks at high temperatures and pressures. Exploiting these resources necessitates novel methods for drilling, stimulation, and maintenance, under operating conditions difficult or impossible to test in laboratory settings. Physically rigorous numerical modeling tools are vital to highlight potential risks, guide process optimization and reduce the uncertainties involved in these developing technologies. In this presentation, we discuss a numerical modeling effort investigating the multiscale mechanics of thermal spallation drilling (TSD) - a technique in which rock is fragmented into small flakes by a high temperature fluid jet. This process encompasses interconnected phenomena on several length and time scales: from system-scale fluid dynamics to grain-scale thermomechanics of spallation. Here we describe how these disperate scales are simulated using GEODYN, a parallel Eulerian compressible solid and fluid dynamics code with adaptive mesh refinement (AMR) capabilities. GEODYN is able to simulate materials under extremely large deformations, resolve details of wave propagation within grains, and uses a continuum damage mechanics approach to represent fracture. We will present results from both system- and grain-scale simulations describing the transfer of heat from the high temperature jet to the rock face, and the effect of grain-scale properties such as incipient flaw distribution, grain size and grain size distribution, heat flux, applied temperature and material heterogeneity on the onset of spallation. Detailed computer modeling helps to address several of the uncertainties surrounding TSD: 1) What rock compositions are drillable with TSD? 2) How do grain size and grain size distribution affect TSD and drilling rates? 3) What combination of macroscopic (Poisson ratio, heat capacity and thermal conductivity) and microscopic (flaw distribution

  8. Effect of Substrate Thickness on Oxide Scale Spallation for Solid Oxide Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wenning N.; Sun, Xin; Stephens, Elizabeth V.; Khaleel, Mohammad A.

    2011-07-01

    In this paper, the effect of the ferritic substrate's thickness on the delamination/spallation of the oxide scale was investigated experimentally and numerically. At the high-temperature oxidation environment of solid oxide fuel cells (SOFCs), a combination of growth stress with thermal stresses may lead to scale delamination/buckling and eventual spallation during SOFC stack cooling, even leading to serious degradation of cell performance. The growth stress is induced by the growth of the oxide scale on the scale/substrate interface, and thermal stress is induced by a mismatch of the coefficient of thermal expansion between the oxide scale and the substrate. The numerical results show that the interfacial shear stresses, which are the driving force of scale delamination between the oxide scale and the ferritic substrate, increase with the growth of the oxide scale and also with the thickness of the ferritic substrate; i.e., the thick ferritic substrate can easily lead to scale delamination and spallation. Experimental observation confirmed the predicted results of the delamination and spallation of the oxide scale on the ferritic substrate.

  9. The mechanical reliability of alumina scales and coatings

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, K.B.; Pruebner, K.; Tortorelli, P.F. [Oak Ridge National Lab., TN (United States)

    1996-08-01

    The mechanical integrity of oxide scales ultimately determines their ability to protect materials from corrosion and other environmental effects arising from deleterious reactions with gases and condensable products. The microstructure and mechanical behavior of alumina products thermally grown or deposited on Fe-28 at.% Al intermetallic alloys are being characterized in order to develop the knowledge and means to control the mechanical reliability of alumina scales by microstructural manipulation through design and processing. Mechanical characterization involved gravimetric data from cyclic oxidation experiments, in-situ observation of oxidized specimens undergoing flexural loading in a scanning electron microscope, and measurements of hardness, elastic modulus and cracking resistance by nanoindentation. Values of cracking thresholds for Al{sub 2}O{sub 3} scales were consistent with other measurements for surface and bulk alumina. The oxidation behavior of Fe{sub 3}Al alloys coated with a thin (0.5 - 1 {mu}m) alumina film deposited by plasma synthesis has been studied. During exposure in the oxidizing environment, new oxide was formed between the coating and the substrate. The presence of the deposited amorphous oxide inhibited the subsequent thermal oxidation of the metal. Because the thermally grown alumina forms under the deposit, the adherence of the coating is controlled by the strength of the metal/oxide interface that develops during oxidation.

  10. SPALLATION ANALYSIS WITH A CLOSED TRANS-SCALE FORMULATION OF DAMAGE EVOLUTION

    Institute of Scientific and Technical Information of China (English)

    WANG Haiying; BAI Yilong; XIA Mengfen; KE Fujiu

    2004-01-01

    A closed, trans-scale formulation of damage evolution based on the statistical microdamage mechanics is summarized in this paper. The dynamic function of damage bridges the mesoscopic and macroscopic evolution of damage. The spallation in an aluminium plate is studied with this formulation. It is found that the damage evolution is governed by several dimensionless parameters,i.e., imposed Deborah numbers De* and De, Mach number M and damage number S. In particular,the most critical mode of the macroscopic damage evolution, i.e., the damage localization, is determined by Deborah number De*. Deborah number De* reflects the coupling and competition between the macroscopic loading and the microdamage growth. Therefore, our results reveal the multi-scale nature of spallation. In fact, the damage localization results from the nonlinearity of the microdamage growth. In addition, the dependence of the damage rate on imposed Deborah numbers De* and De,Mach number M and damage number S is discussed.

  11. Ionic Segregation on Grain Boundaries in Thermally Grown Alumina Scales

    Energy Technology Data Exchange (ETDEWEB)

    Pint, Bruce A [ORNL; Unocic, Kinga A [ORNL

    2012-01-01

    This study first examined segregation behaviour in the alumina scale formed after 100 h at 1100 C on bare and MCrAlYHfSi-coated single-crystal superalloys with {approx}10 ppma La and Y. For the bare superalloy, Hf and Ti were detected on the grain boundaries of the inner columnar alumina layer. Increasing the oxidation temperature to 1200 C for 2 h did not change the segregation behavior. With the bond coating, both Y and Hf were segregated to the grain boundaries as expected. However, there was evidence of Ti-rich oxide particles near the gas interface suggesting that Ti diffused from the superalloy through the coating. To further understand these segregation observations with multiple dopants, other alumina-forming systems were examined. Alumina scale grain boundary co-segregation of Ti with Y is common for FeCrAl alloys. Co-segregation of Hf and Ti was observed in the scale formed on co-doped NiAl. No La segregation was detected in the scale formed on NiCrAl with only a 19 ppma La addition, however, the scale was adherent.

  12. Mitigation and Prediction of Spallation of Oxide Scales on Ferritic Stainless Steel

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Y. S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stephens, Elizabeth V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Xu, Zhijie [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Xu, Wei [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Koeppel, Brian J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stevenson, Jeffry W. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-02-04

    This report summarizes results from experimental and modeling studies performed by researchers at Pacific Northwest National Laboratory on behalf of the Solid-State Energy Conversion Alliance (SECA) Core Technology Program. The results indicate that application of physical surface modifications, such as surface blasting, prior to application of protective surface coatings can substantially increase oxide scale spallation resistance during long-term exposure to elevated temperatures (e.g., 800-850ºC). To better understand and predict the benefits of surface modification, an integrated modeling framework was developed and applied to the obtained experimental results.

  13. Corrosion performance of alumina scales in coal gasification environments

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K. [Argonne National Laboratory, Argonne, IL (United States)

    1997-12-31

    Corrosion of metallic structural materials in complex gas environments of coal gasification is a potential problem. The corrosion process is dictated by concentrations of two key constituents: sulfur as H{sub 2}s and C1 as HCl. This paper examines the corrosion performance of alumina scales that are thermally grown on Fe-base alloys during exposure to O/S mixed-gas environments. The results are compared with the performance of chromia-forming alloys in similar environments. The valuable information on corrosion performance of alloys whose surfaces were enriched with Al by the pack-diffusion process, by the electrospark deposition process, or by weld overlay techniques, is also discussed.

  14. Corrosion performance of alumina scales in coal gasification environments

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.

    1997-02-01

    Corrosion of metallic structural materials in complex gas environments of coal gasification is a potential problem. The corrosion process is dictated by concentrations of two key constituents: sulfur as H{sub 2}S and Cl as HCl. This paper examines the corrosion performance of alumina scales that are thermally grown on Fe-base alloys during exposure to O/S mixed-gas environments. The results are compared with the performance of chromia-forming alloys in similar environments. The paper also discusses the available information on corrosion performance of alloys whose surfaces were enriched with Al by the pack-diffusion process, by the electrospark deposition process, or by weld overlay techniques.

  15. Moisture-Induced Delayed Alumina Scale Spallation on a Ni(Pt)Al Coating (Preprint)

    Science.gov (United States)

    2009-04-01

    with increase in p(H2O) [21,35 Janakiraman 1999, Maris- Sida 2003]. However the same effect was not especially evident for the more oxidation resistant...Tolpygo 2007, Maris- sida 2003). Crystallographically aligned surface striations and pits are also evident, presumably an artifact of the CVD...A similar but less severe effect was reported for the same coating on Rene´N5 (35 Maris- Sida , 2003), exhibiting a loss of 1 mg/cm2 in wet air

  16. Formation of x-ray Newton’s rings from nano-scale spallation shells of metals in laser ablation

    Directory of Open Access Journals (Sweden)

    Masaharu Nishikino

    2017-01-01

    Full Text Available The initial stages of the femtosecond (fs laser ablation process of gold, platinum, and tungsten were observed by single-shot soft x-ray imaging technique. The formation and evolution of soft x-ray Newton’s rings (NRs were found for the first time. The soft x-ray NRs are caused by the interference between the bulk ablated surface and nanometer-scale thin spallation layer; they originate from the metal surface at pump energy fluence of around 1 J/cm2 and work as a flying soft x-ray beam splitter.

  17. Formation of x-ray Newton's rings from nano-scale spallation shells of metals in laser ablation

    Science.gov (United States)

    Nishikino, Masaharu; Hasegawa, Noboru; Tomita, Takuro; Minami, Yasuo; Eyama, Takashi; Kakimoto, Naoya; Izutsu, Rui; Baba, Motoyoshi; Kawachi, Tetsuya; Suemoto, Tohru

    2017-01-01

    The initial stages of the femtosecond (fs) laser ablation process of gold, platinum, and tungsten were observed by single-shot soft x-ray imaging technique. The formation and evolution of soft x-ray Newton's rings (NRs) were found for the first time. The soft x-ray NRs are caused by the interference between the bulk ablated surface and nanometer-scale thin spallation layer; they originate from the metal surface at pump energy fluence of around 1 J/cm2 and work as a flying soft x-ray beam splitter.

  18. Rapid fabrication of self-ordered porous alumina with 10-/sub-10-nm-scale nanostructures by selenic acid anodizing.

    Science.gov (United States)

    Nishinaga, Osamu; Kikuchi, Tatsuya; Natsui, Shungo; Suzuki, Ryosuke O

    2013-09-25

    Anodic porous alumina has been widely investigated and used as a nanostructure template in various nanoapplications. The porous structure consists of numerous hexagonal cells perpendicular to the aluminum substrate and each cell has several tens or hundreds of nanoscale pores at its center. Because the nanomorphology of anodic porous alumina is limited by the electrolyte during anodizing, the discovery of additional electrolytes would expand the applicability of porous alumina. In this study, we report a new self-ordered nanoporous alumina formed by selenic acid (H2SeO4) anodizing. By optimizing the anodizing conditions, anodic alumina possessing 10-nm-scale pores was rapidly assembled (within 1 h) during selenic acid anodizing without any special electrochemical equipment. Novel sub-10-nm-scale spacing can also be achieved by selenic acid anodizing and metal sputter deposition. Our new nanoporous alumina can be used as a nanotemplate for various nanostructures in 10-/sub-10-nm-scale manufacturing.

  19. EFFECT OF SURFACE CONDITION ON SPALLATION BEHAVIOR OF OXIDE SCALE ON SS 441 SUBSTRATE USED IN SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wenning N.; Sun, Xin; Stephens, Elizabeth V.; Khaleel, Mohammad A.

    2011-03-01

    As operating temperature of SOFC decreases, ferritic stainless steel has attracted a great deal of attention for its use as an interconnect in SOFCs because of its gas-tightness, low electrical resistivity, ease of fabrication, and cost-effectiveness. However, oxidation reaction of the metallic interconnects in a typical SOFC working environment is unavoidable. The growth stresses in the oxide scale and on the scale/substrate interface combined with the thermal stresses induced by thermal expansion coefficient mismatch between the oxide scale and the substrate may lead to scale delamination/buckling and eventual spallation during stack cooling, which can lead to serious cell performance degradation. Therefore, the interfacial adhesion strength between the oxide scale and substrate is crucial to the reliability and durability of the metallic interconnect in SOFC operating environments. In this paper, we investigated the effect of the surface conditions on the interfacial strength of oxide scale and SS441 substrate experimentally. Contrary to the conventional sense, it was found that rough surface of SS441 substrate will decrease the interfacial adhesive strength of the oxide scale and SS441 substrate

  20. The mechanical reliability of alumina scales and coatings

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, K.B.; Pruebner, K.; Tortorelli, P.F.

    1996-06-01

    In many high-temperature fossil energy systems, corrosion and deleterious reactions with gases and condensable products in the operating environment often compromise materials performance. The presence of a stable surface oxide (either as thermally-grown scales or deposited coatings) can effectively protect the materials from these reactions if the oxides are slow-growing, dense and adherent to the substrate. The protection these brittle oxide films provide has long been a critical issue, particularly for applications involving severe high-temperature thermal cycles or very aggressive (for example, sulfidizing) environments. The various factors which control the scale/coating integrity and adherence are not well understood. The present multilaboratory collaborative work is intended to define the relationships between substrate characteristics (composition, microstructure, and mechanical behavior) and the structure and protective properties of deposited oxide coatings and/or thermally grown scales. Through such studies, the ultimate goal is to assure environmental protection through effective processing and materials selection leading to the development of corrosion-resistant, high-temperature materials for improved energy and environmental control systems.

  1. Ultra-High Density Single Nanometer-Scale Anodic Alumina Nanofibers Fabricated by Pyrophosphoric Acid Anodizing

    Science.gov (United States)

    Kikuchi, Tatsuya; Nishinaga, Osamu; Nakajima, Daiki; Kawashima, Jun; Natsui, Shungo; Sakaguchi, Norihito; Suzuki, Ryosuke O.

    2014-12-01

    Anodic oxide fabricated by anodizing has been widely used for nanostructural engineering, but the nanomorphology is limited to only two oxides: anodic barrier and porous oxides. Therefore, the discovery of an additional anodic oxide with a unique nanofeature would expand the applicability of anodizing. Here we demonstrate the fabrication of a third-generation anodic oxide, specifically, anodic alumina nanofibers, by anodizing in a new electrolyte, pyrophosphoric acid. Ultra-high density single nanometer-scale anodic alumina nanofibers (1010 nanofibers/cm2) consisting of an amorphous, pure aluminum oxide were successfully fabricated via pyrophosphoric acid anodizing. The nanomorphologies of the anodic nanofibers can be controlled by the electrochemical conditions. Anodic tungsten oxide nanofibers can also be fabricated by pyrophosphoric acid anodizing. The aluminum surface covered by the anodic alumina nanofibers exhibited ultra-fast superhydrophilic behavior, with a contact angle of less than 1°, within 1 second. Such ultra-narrow nanofibers can be used for various nanoapplications including catalysts, wettability control, and electronic devices.

  2. Atomic-scale non-contact AFM studies of alumina supported nanoparticles

    DEFF Research Database (Denmark)

    Jensen, Thomas Nørregaard; Meinander, Kristoffer; Simonsen, Søren Bredmose

    ATOMIC-SCALE NON-CONTACT ATOMIC FORCE STUDIES OF ALUMINA SUPPORTED NANOPARTICLES Thomas N. Jensen, Kristoffer Meinander, Flemming Besenbacher and Jeppe V. Lauritsen Interdisciplinary Nanoscience Center, Aarhus University, DK-8000 Aarhus C, Denmark Heterogeneous catalysis plays a crucial role...... materials is a prerequisite for the synthesis of more sintering stable catalysts and the realizations of nanocatalysts implementing catalyst particles with a tailored size and morphology. In the last two decades the atomic force microscope (AFM) has become one of the premier tools for studying surfaces...... at the nanometre scale [1]. When operated in the so-called non-contact mode (nc-AFM), this technique yields genuine atomic resolution and offers a unique tool for atomic-scale studies of clean surfaces, as well as, nanoparticles and thin films on these surfaces irrespective of the substrate being electrically...

  3. Oxygen Permeability and Grain-Boundary Diffusion Applied to Alumina Scales

    Science.gov (United States)

    Smialek, James L.; Jacobson, Nathan S.; Gleeson, Brian; Hovis, David B.; Heuer, Arthur H.

    2013-01-01

    High-temperature oxygen permeability measurements had determined grain-boundary diffusivities (deltaD(sub gb)) in bulk polycrystalline alumina (Wada, Matsudaira, and Kitaoka). They predict that oxygen deltaD(sub gb,O) varies with oxygen pressure as P(O2)(sup -1/6) at low pressure whereas aluminum deltaD(sub gb),Al varies with P(O2)(sup +3/16) at high pressure. These relations were used to evaluate alumina scale growth in terms of diffusivity and grain size. A modified Wagner treatment for dominant inward oxygen growth produces the concise solution: ?(sub i) = k(sub p,i)×G(sub i) = 12 deltaD(sub gb,O,int), where ?(sub i) is a constant and k(sub p,i) and G(sub i) refer to instantaneous values of the scale parabolic growth constant and grain size, respectively. A commercial FeCrAl(Zr) alloy was oxidized at 1100 to 1400 degC to determine k(sub p,i), interfacial grain size, ?, and thus deltaD(sub gb,O,int). The deltaD(sub gb,O,int) values predicted from oxidation at (375 kJ/mole) were about 20 times less than those obtained above (at 298 kJ/mole), but closer than extrapolations from high-temperature bulk measurements. The experimental oxidation results agree with similar FeCrAl(X) studies, especially where both k(sub p,i) and G(sub i) were characterized. This complete approach accounts for temperature-sensitive oxidation effects of grain enlargement, equilibrium interface pressure variation, and grain-boundary diffusivity.

  4. Growth strains and stress relaxation in alumina scales during high temperature oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Hou, P.Y.; Paulikas, A.P.; Veal, B.W.

    2004-03-23

    A novel X-ray technique was used, exploiting synchrotron radiation at the Advanced Photon Source at Argonne National Laboratory, to investigate the growth stresses in {alpha}-Al{sub 2}O{sub 3}. In-situ measurements of Debye-Scherrer diffraction patterns from the scale were recorded during oxidation and cooling, and the elliptical distortion of the diffraction rings was analyzed to yield the in-plane strain. Fe-28Al, Fe-40Al, Fe-40Al-0.2Hf, Fe-20Cr-10Al and Ni-50Al (at. %) were studied. Data were acquired in air at temperatures between 950-1100 C and during cool down. In all cases, the steady stage growth strain was relatively low (<0.1%) and was either tensile or compressive depending on the alloy. A higher tensile strain often existed during the initial oxidation period when transition alumina was present. Thermal stresses imposed on NiAl by reducing the sample temperature to 950 C for a period of time showed noticeable stress relaxation by creep. Different degrees of relaxation were also found during cooling depending on alloy composition and scale microstructure. On all Fe-based alloys, the first formed {alpha}-Al{sub 2}O{sub 3} was highly textured with the degree of texture decreasing with further oxidation. The relationships between stress development, scale wrinkling, oxide phase changes, and the effect of reactive element addition on growth stresses are discussed. Results are compared with other reports of growth stresses in Al{sub 2}O{sub 3} scales.

  5. Spallation Neutron Source (SNS)

    Data.gov (United States)

    Federal Laboratory Consortium — The SNS at Oak Ridge National Laboratory is a next-generation spallation neutron source for neutron scattering that is currently the most powerful neutron source in...

  6. Spallation modeling in tantalum

    Energy Technology Data Exchange (ETDEWEB)

    Tonks, D.L.; Hixson, R.; Zurek, A.K.; Thissell, W.

    1997-09-01

    A gas gun plate impact spallation experiment has been performed on commercial purity rolled tantalum. The shock pressure achieved was about 7 Gpa and was sufficient to induce incipient spallation. The particle velocity was measured at the free surface of the spalled plate, and the spalled sample was recovered and examined metallographically using image analysis. The quantitative image analysis results are being used to develop a damage model. The model is micromechanically based and involves novel void growth and coalescence processes. The 1D characteristics code CHARADE has been used in a preliminary simulation of the VISAR free surface particle velocity record. Implications for ductile damage modeling will be discussed.

  7. Pulsed spallation Neutron Sources

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, J.M. [Argonne National Lab., IL (United States)

    1994-12-31

    This paper reviews the early history of pulsed spallation neutron source development at Argonne and provides an overview of existing sources world wide. A number of proposals for machines more powerful than currently exist are under development, which are briefly described. The author reviews the status of the Intense Pulsed Neutron Source, its instrumentation, and its user program, and provides a few examples of applications in fundamental condensed matter physics, materials science and technology.

  8. Enigmatic Moisture Effects on Al2O3 Scale and TBC Adhesion

    Science.gov (United States)

    Smialek, James L.

    2008-01-01

    Alumina scale adhesion to high temperature alloys is known to be affected primarily by sulfur segregation and reactive element additions. However, adherent scales can become partially compromised by excessive strain energy and cyclic cracking. With time, exposure of such scales to moisture can lead to spontaneous interfacial decohesion, occurring while the samples are maintained at ambient conditions. Examples of this Moisture-Induced Delayed Spallation (MIDS) are presented for NiCrAl and single crystal superalloys, becoming more severe with sulfur level and cyclic exposure conditions. Similarly, delayed failure or Desk Top Spallation (DTS) results are reviewed for thermal barrier coatings (TBCs), culminating in the water drop failure test. Both phenomena are discussed in terms of moisture effects on bulk alumina and bulk aluminides. A mechanism is proposed based on hydrogen embrittlement and is supported by a cathodic hydrogen charging experiment. Hydroxylation of aluminum from the alloy interface appears to be the relevant basic reaction.

  9. Further considerations of spallation effects

    Science.gov (United States)

    Dyer, C.

    1973-01-01

    Trapped photon and cosmic ray effects on spallation in the UK-5 (hard X ray telescope) central crystal were measured. Both low dose and high dose effects were considered. Decay results are presented in tables.

  10. Outline of spallation neutron source engineering

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Noboru [Center for Neutron Science, Tokai Research Establishment, Japan Atomic Energy Research Institute, Tokai, Ibaraki (Japan)

    2001-01-01

    Slow neutrons such as cold and thermal neutrons are unique probes which can determine structures and dynamics of condensed matter in atomic scale. The neutron scattering technique is indispensable not only for basic sciences such as condensed matter research and life science, but also for basic industrial technology in 21 century. It is believed that to survive in the science-technology competition in 21 century would be almost impossible without neutron scattering. However, the intensity of neutrons presently available is much lower than synchrotron radiation sources, etc. Thus, R and D of intense neutron sources become most important. The High-Intensity Proton Accelerator Project is now being promoted jointly by Japan Atomic Energy Research Institute and High Energy Accelerator Research Organization, but there has so far been no good text which covers all the aspects of pulsed spallation neutron sources. The present review was prepare aiming at giving a better understanding on pulsed spallation neutron sources not only to neutron source researchers but also more widely to neutron scattering researchers and accelerator scientists in this field. The contents involve, starting from what is neutron scattering and what neutrons are necessary for neutron scattering, what is the spallation reaction, how to produce neutrons required for neutron scattering more efficiently, target-moderator-reflector neutronics and its engineering, shielding, target station, material issues, etc. The author have engaged in R and D of pulsed apallation neutron sources and neutron scattering research using them over 30 years. The present review is prepared based on the author's experiences with useful information obtained through ICANS collaboration and recent data from the JSNS (Japanese Spallation Neutron Source) design team. (author)

  11. Preparation and testing of corrosion and spallation-resistant coatings

    Energy Technology Data Exchange (ETDEWEB)

    Hurley, John P. [Univ. of North Dakota, Grand Forks, ND (United States); Cavalli, Matthew N. [Univ. of North Dakota, Grand Forks, ND (United States)

    2016-06-30

    The goal of this project was to take a recently developed method of bonding oxide dispersion-strengthened (ODS) FeCrAl plating to nickel superalloys closer to commercial use in syngas-fired turbines. The project was designed to better understand and develop the bonding process and to determine if plating APMT®, a specific highly oxidation-resistant ODS FeCrAl alloy made by Kanthal, onto nickel-based superalloy turbine parts is a viable method for substantially improving the lifetimes and maximum use temperatures of the parts. The superalloys investigated for protection were CM247LC and Rene® 80, both alumina scale-forming alloys. The method for bonding the APMT plate to the superalloys is called evaporative metal bonding, which involves placing a thin foil of zinc between the plate and the superalloy, clamping them together, and heating in an atmosphere-controlled furnace. Upon heating, the zinc melts and dissolves the oxide skins of the alloys at the bond line, allowing the two alloys to diffuse into each other. The zinc then diffuses through the alloys and evaporates from their surfaces, creating a bond between the APMT and the superalloy that is stronger than the APMT itself. Testing showed that the diffusivity of zinc in both APMT and CM247LC is quite similar at 700°C but 15 times higher in the APMT at 1214°C. Coefficients of thermal expansion were determined for each of the alloys as a function of temperature. This information was entered into a finite-element model using ANSYS, which was used to design a clamping jig for pressing the APMT to the superalloys at the bonding temperature. Scanning electron microscopy analyses of representative joints showed that no zinc remained in the alloys after bonding Unfortunately, the analyses also showed some small pieces of broken aluminum oxide scale near the bond lines, indicating that its scale was not sufficiently removed during prebonding cleaning. Samples from each of the bonded blocks were sent to Siemens for

  12. Influences of Yttrium on Adhesion of Oxide Scale of Fe-Cr-Al Alloy

    Institute of Scientific and Technical Information of China (English)

    辛丽; 李美栓; 周龙江; 王福会; 李铁藩

    2001-01-01

    The 1100 ℃ isothermal oxidation behavior of Fe-23Cr-5Al alloy modified by yttrium addition was studied by means of thermogravimetric analysis, scanning electron microscopy and energy dispersive X-ray analysis. Yttrium was added to this alloy in the forms of metallic addition, yttrium oxide and ion implant. Cracking and spalling occurred on the convoluted scale formed on Y-free alloy and exposed the substrate. A flat dense scale without spallation was formed on the yttrium alloying addition or yttrium oxide dispersion alloy. The scale adhesion was also improved by 1×1017Y+/cm2-implantation. The results indicate the convoluted morphology of the scale on Fe-23Cr-5Al-0.21Ti alloy is related to the growth mechanism of the alumina scale, and the spallation of the scale is related to sulfur segregation at the scale/alloy interface. The main reason that the adhesion of alumina scale is improved by yttrium addition lies in the following. Yttrium is liable to form a stable yttrium sulfide with sulfur in the alloy and prevent sulfur interface from segregation. Another reason is that the growth mechanism of alumina scale is changed by yttrium addition.

  13. Materials for spallation neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, W.F.; Daemen, L.L. [comps.

    1996-03-01

    The Workshop on Materials for Spallation Neutron Sources at the Los Alamos Neutron Science Center, February 6 to 10, 1995, gathered scientists from Department of Energy national laboratories, other federal institutions, universities, and industry to discuss areas in which work is needed, successful designs and use of materials, and opportunities for further studies. During the first day of the workshop, speakers presented overviews of current spallation neutron sources. During the next 3 days, seven panels allowed speakers to present information on a variety of topics ranging from experimental and theoretical considerations on radiation damage to materials safety issues. An attempt was made to identify specific problems that require attention within the context of spallation neutron sources. This proceedings is a collection of summaries from the overview sessions and the panel presentations.

  14. Status of spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Oyama, Yukio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-03-01

    Existing and planned facilities using proton accelerator driven spallation neutron source are reviewed. These include new project of neutron science proposed from Japan Atomic Energy Research Institute. The present status of facility requirement and accelerator technology leads us to new era of neutron science such as neutron scattering research and nuclear transmutation study using very intense neutron source. (author)

  15. Developing a Small-Scale De-Fluoridation Filter for Use in Rural Northern Ghana with Activated Alumina As the Sorbent

    Science.gov (United States)

    Craig, L.; Stillings, L. L.

    2014-12-01

    reaction time, the larger grain size adsorbed only 59% of F-, while at the finer grain size 90% was adsorbed. Future work will determine the volume of high F- water that can be treated before activated alumina needs to be regenerated or changed. These data will aid in the design of a small-scale F- adsorption filter in the study area, and will predict the longevity of activated alumina as the sorbent.

  16. Spallation radiation effects in materials

    Energy Technology Data Exchange (ETDEWEB)

    Mansur, L.K.; Farrell, K.; Wechsler, M.S. [Oak Ridge National Lab., TN (United States)

    1996-06-01

    Spallation refers to the process whereby particles (chiefly neutrons) are ejected from nuclei upon bombardment by high-energy protons. Spallation neutron sources (SNS`s) use these neutrons for neutron scattering and diffraction research, and SNS`s are proposed as the basis for systems for tritium production and transmutation of nuclear waste. Materials in SNS`s are exposed to the incident proton beam (energies typically about 1000 MeV) and to the spallation neutrons (spectrum of energies extending up to about 1000 MeV). By contrast the fission neutrons in nuclear reactors have an average energy of only about 2 MeV, and the neutrons in fusion reactors would have energies below about 14 MeV. Furthermore, the protons and neutrons in SNS`s for scattering and diffraction research are pulsed at frequencies of about 10 to 60 Hz, from which significant changes in the kinetics of point and extended defects may be expected. In addition, much higher transmutation rates occur in SNS-irradiated materials, On the whole, then, significant differences in microstructural development and macroscopic properties may result upon exposure in SNS systems, as compared with fission and fusion irradiations. In a more general sense, subjecting materials to new radiation environments has almost routinely led to new discoveries. To the extent that data are avaiable, however, the spallation environment appears to increase the degree of damage without introducing totally new effects. The first part of this presentation is an overview of radiation effects in materials, outlining essential concepts and property changes and their physical bases. This background is followed by a description of SNS irradiation environments and the effects on materials of exposure to these environments. A special discussion is given of the selection of target (e.g., liquid mercury), container (e.g., austenitic stainless steel or ferritic/martensitic steel), and structural materials in SNS systems.

  17. Spallator: a new option for nuclear power

    Energy Technology Data Exchange (ETDEWEB)

    Steinberg, M.; Grand, P.; Takahashi, H.; Powell, J.R.; Kouts, H.J.

    1983-06-01

    The principles of the spallator reactor are reviewed. Advances in linear accelerator technology allow the design and construction of high current (hundreds of mA) continuous wave high energy (thousands of MeV) proton machines in the near term. Spallation neutronic calculations building on existing experimental results, indicate substantial neutron yields on uranium targets. Spallator target assembly designs based on water cooled reactor technology indicate operable efficient systems. Fuel cycles are presented which supply fissile material to thermal power reactors and reduce fission product waste. Preliminary comparative analysis indicates an economically competitive system in which a single purpose self-sufficient spallator supplies fuel to a number of LWRs. The spallator assures a long-term LWR power reactor economy. International interest in advancing the technology is indicated.

  18. PREFACE: Neutrino physics at spallation neutron sources

    Science.gov (United States)

    Avignone, F. T.; Chatterjee, L.; Efremenko, Y. V.; Strayer, M.

    2003-11-01

    Unique because of their super-light masses and tiny interaction cross sections, neutrinos combine fundamental physics on the scale of the miniscule with macroscopic physics on the scale of the cosmos. Starting from the ignition of the primal p-p chain of stellar and solar fusion reactions that signal star-birth, these elementary leptons (neutrinos) are also critical players in the life-cycles and explosive deaths of massive stars and the production and disbursement of heavy elements. Stepping beyond their importance in solar, stellar and supernova astrophysics, neutrino interactions and properties influence the evolution, dynamics and symmetries of the cosmos as a whole. Further, they serve as valuable probes of its material content at various levels of structure from atoms and nuclei to valence and sea quarks. In the light of the multitude of physics phenomena that neutrinos influence, it is imperative to enhance our understanding of neutrino interactions and properties to the maximum. This is accentuated by the recent evidence of finite neutrino mass and flavour mixing between generations that reverberates on the plethora of physics that neutrinos influence. Laboratory experiments using intense neutrino fluxes would allow precision measurements and determination of important neutrino reaction rates. These can then complement atmospheric, solar and reactor experiments that have enriched so valuably our understanding of the neutrino and its repertoire of physics applications. In particular, intermediate energy neutrino experiments can provide critical information on stellar and solar astrophysical processes, along with advancing our knowledge of nuclear structure, sub-nuclear physics and fundamental symmetries. So where should we look for such intense neutrino sources? Spallation neutron facilities by their design are sources of intense neutrino pulses that are produced as a by-product of neutron spallation. These neutrino sources could serve as unique laboratories

  19. Dose measurements around spallation neutron sources.

    Science.gov (United States)

    Fragopoulou, M; Stoulos, S; Manolopoulou, M; Krivopustov, M; Zamani, M

    2008-01-01

    Neutron dose measurements and calculations around spallation sources appear to be of great importance in shielding research. Two spallation sources were irradiated by high-energy proton beams delivered by the Nuclotron accelerator (JINR), Dubna. Neutrons produced by the spallation sources were measured by using solid-state nuclear track detectors. In addition, neutron dose was calculated after polyethylene and concrete, using a phenomenological model based on empirical relations applied in high-energy physics. The study provides an analytical and experimental neutron benchmark analysis using the transmission factor and a comparison between the experimental results and calculations.

  20. Calcium aluminate in alumina

    Science.gov (United States)

    Altay, Arzu

    The properties of ceramic materials are determined not only by the composition and structure of the phases present, but also by the distribution of impurities, intergranular films and second phases. The phase distribution and microstructure both depend on the fabrication techniques, the raw materials used, the phase-equilibrium relations, grain growth and sintering processes. In this dissertation research, various approaches have been employed to understand fundamental phenomena such as grain growth, impurity segregation, second-phase formation and crystallization. The materials system chosen was alumina intentionally doped with calcium. Atomic-scale structural analyses of grain boundaries in alumina were carried on the processed samples. It was found that above certain calcium concentrations, CA6 precipitated as a second phase at all sintering temperatures. The results also showed that abnormal grain growth can occur after precipitation and it is not only related to the calcium level, but it is also temperature dependent. In order to understand the formation mechanism of CA6 precipitates in calcium doped alumina samples, several studies have been carried out using either bulk materials or thin films The crystallization of CA2 and CA6 powders has been studied. Chemical processing techniques were used to synthesize the powders. It was observed that CA2 powders crystallized directly, however CA6 powders crystallized through gamma-Al 2O3 solid solution. The results of energy-loss near-edge spectrometry confirmed that gamma-Al2O3 can dissolve calcium. Calcium aluminate/alumina reaction couples have also been investigated. All reaction couples were heat treated following deposition. It was found that gamma-Al2O3 was formed at the interface as a result of the interfacial reaction between the film and the substrate. gamma-Al 2O3 at the interface was stable at much higher temperatures compared to the bulk gamma-Al2O3 formed prior to the CA6 crystallization. In order to

  1. Fracture toughness of advanced alumina ceramics and alumina matrix composites used for cutting tool edges

    Directory of Open Access Journals (Sweden)

    M. Szutkowska

    2012-10-01

    Full Text Available Purpose: Specific characteristics in fracture toughness measurements of advanced alumina ceramics and alumina matrix composites with particular reference to α-Al2O3, Al2O3-ZrO2, Al2O3-ZrO2-TiC and Al2O3-Ti(C,N has been presented.Design/methodology/approach: The present study reports fracture toughness obtained by means of the conventional method and direct measurements of the Vickers crack length (DCM method of selected tool ceramics based on alumina: pure alumina, alumina-zirconia composite with unstabilized and stabilized zirconia, alumina–zirconia composite with addition of TiC and alumina–nitride-carbide titanium composite with 2wt% of zirconia. Specimens were prepared from submicro-scale trade powders. Vicker’s hardness (HV1, fracture toughness (KIC at room temperature, the indentation fracture toughness, Young’s modulus and apparent density were also evaluated. The microstructure was observed by means of scanning electron microscopy (SEM.Findings: The lowest value of KIC is revealed by pure alumina ceramics. The addition of (10 wt% unstabilized zirconia to alumina or a small amount (5 wt% of TiC to alumina–zirconia composite improve fracture toughness of these ceramics in comparison to alumina ceramics. Alumina ceramics and alumina-zirconia ceramics reveal the pronounced character of R-curve because of an increasing dependence on crack growth resistance with crack extension as opposed to the titanium carbide-nitride reinforced composite based on alumina. R-curve has not been observed for this composite.Practical implications: The results show the method of fracture toughness improvement of alumina tool ceramics.Originality/value: Taking into account the values of fracture toughness a rational use of existing ceramic tools should be expected.

  2. Study of spallation by sub-picosecond laser driven shocks in metals

    Directory of Open Access Journals (Sweden)

    Combis P.

    2011-01-01

    Full Text Available Spallation induced by a laser driven shock has been studied for two decades on time scales of nanosecond order. The evolution of laser technologies now provides access to sources whose pulse duration is under the picosecond, corresponding to characteristic times of numerous microscopic phenomena. In this ultra-short irradiation regime, spallation experiments have been performed with time-resolved measurements of the free surface. In this solicitation type, damage occurs at small scale, leading to micrometric spalls. The VISAR measurements have been complemented with post-test observations and microtomography and compared with numerical simulations to check the models consistency of the laser-matter interaction, shock wave propagation and the dynamic damage criteria ability to reproduce spallation at this ultra-short time scale, inducing strong tensile stress states at very high strain rates.

  3. Physics and technology of spallation neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, G.S.

    1998-08-01

    Next to fission and fusion, spallation is an efficient process for releasing neutrons from nuclei. Unlike the other two reactions, it is an endothermal process and can, therefore, not be used per se in energy generation. In order to sustain a spallation reaction, an energetic beam of particles, most commonly protons, must be supplied onto a heavy target. Spallation can, however, play an important role as a source of neutrons whose flux can be easily controlled via the driving beam. Up to a few GeV of energy, the neutron production is roughly proportional to the beam power. Although sophisticated Monte Carlo codes exist to compute all aspects of a spallation facility, many features can be understood on the basis of simple physics arguments. Technically a spallation facility is very demanding, not only because a reliable and economic accelerator of high power is needed to drive the reaction, but also, and in particular, because high levels of radiation and heat are generated in the target which are difficult to cope with. Radiation effects in a spallation environment are different from those commonly encountered in a reactor and are probably even more temperature dependent than the latter because of the high gas production rate. A commonly favored solution is the use of molten heavy metal targets. While radiation damage is not a problem in this case, except for the container, a number of other issues are discussed. (author)

  4. Novel self assembly behavior for γ-alumina nanoparticles

    Institute of Scientific and Technical Information of China (English)

    Osama Saber

    2012-01-01

    In this study,self assembly behavior was induced for γ-alumina nanoparticles by adsorption of dimethyl disulfide.Following this trend,we have developed a chemical process to obtain γ-alumina in the nano scale.Scanning electron microscopy images of the prepared γ-alumina showed big and strong agglomeration of the nanoparticles indicating that these nanoparticles have strong surface forces.Transmission electron microscopy images confirmed that the γ-alumina nanoparticles 3-7 nm in size were converted to uniform spherical shape in the size range of 1-2 mm after shaking with dimethyl disulfide in the presence of n-hexane at room temperature.This phenomenon did not appear in the case of alumina in the micro scale.The surface properties of the prepared γ-alumina in the nano scale were characterized and compared with the γ-alumina in the micro scale by using low temperature nitrogen adsorption-desorption system,indicating that the specific surface area of the prepared γ-alumina nanoparticles is larger than that of the γ-alumina in the micro scale.Furthermore,micro-and meso-pores were observed for the γ-alumina nanoparticles while only mesoporous structure was detected for the γ-alumina in the micro scale.These experimental results suggested that the self assembly behavior of the γ-alumina nanoparticles may be due to the selective adsorption of dimethyl disulfide in the micropores of these nanoparticles to act as bridge linking the nanoparticles.

  5. Synchrotron-driven spallation sources

    CERN Document Server

    Bryant, P J

    1996-01-01

    The use of synchrotrons for pulsed neutron spallation sources is an example of scientific and technological spin-off from the accelerator development for particle physics. Accelerator-driven sources provide an alternative to the continuous-flux, nuclear reactors that currently furnish the majority of neutrons for research and development. Although the present demand for neutrons can be adequately met by the existing reactors, this situation is unlikely to continue due to the increasing severity of safety regulations and the declared policies of many countries to close down their reactors within the next decade or so. Since the demand for neutrons as a research tool is, in any case,expected to grow, there has been a corresponding interest in sources that are synchrotron-driven or linac-driven with a pulse compression ring and currently several design studies are being made. These accelerator-driven sources also have the advantage of a time structure with a high peak neutron flux. The basic requirement is for a...

  6. Effect of mineral surface properties (alumina, kaolinite) on the sorptive fractionation mechanisms of soil fulvic acids: Molecular-scale ESI-MS studies

    Science.gov (United States)

    Fleury, Guillaume; Del Nero, Mirella; Barillon, Rémi

    2017-01-01

    We addressed the effects of mineral surface properties (kaolinite versus Al-oxide) on the sorption-driven fractionation of a soil fulvic acid (FA) at acidic pH, mainly by means of ESI(-)-FTMS analysis of initial and supernatant solutions of FA sorption batch experiments. The MS data provided clear molecular-scale evidence of distinct mechanisms and molecular parameters controlling the FA fractionation upon its sorption on clay and oxide surfaces, respectively. Identification of sorbing and not-sorbing FA compounds in kaolinite-solution systems revealed a weak fractionation among members of sbnd CO2 series of aliphatics or not-condensed aromatics (NCAs) at pH 3.8, and almost no sorption of poorly-oxygenated polycyclic aromatic compounds (PACs) and NCAs. This first molecular-scale description of a FA fractionation in a clay-solution system suggests that H-bonding with low affinity sites (aluminol/silanol) on the basal planes of the clay particles is the main mechanism of sorption. Due to the predominance of such weak and poorly-selective mechanism, the sorption of aliphatic and NCA molecules bearing oxygenated functionalities was prevented at pH 5, due to dissolved Al competing successfully for their coordination. In contrast, a strong FA fractionation was observed onto alumina, with a preferential retention of PACs and highly-oxygenated aliphatics and NCAs. The major part of the poorly oxygenated aliphatics was left in solution. The sorption degree of NCAs and aliphatics was strongly correlated with molecular acidity. For PACs and poorly-oxygenated NCAs, the sorption was driven by reactions of surface ligand exchange (for the most oxygenated compounds) or by hydrophobic interactions (for the least oxygenated compounds).

  7. Porous Alumina Films with Width-Controllable Alumina Stripes

    Directory of Open Access Journals (Sweden)

    Huang Shi-Ming

    2010-01-01

    Full Text Available Abstract Porous alumina films had been fabricated by anodizing from aluminum films after an electropolishing procedure. Alumina stripes without pores can be distinguished on the surface of the porous alumina films. The width of the alumina stripes increases proportionally with the anodizing voltage. And the pores tend to be initiated close to the alumina stripes. These phenomena can be ascribed to the electric field distribution in the alumina barrier layer caused by the geometric structure of the aluminum surface.

  8. Porous Alumina Films with Width-Controllable Alumina Stripes.

    Science.gov (United States)

    Huang, Kai; Huang, Shi-Ming; Pu, Lin; Shi, Yi; Wu, Zhi-Ming; Ji, Li; Kang, Jun-Yong

    2010-08-21

    Porous alumina films had been fabricated by anodizing from aluminum films after an electropolishing procedure. Alumina stripes without pores can be distinguished on the surface of the porous alumina films. The width of the alumina stripes increases proportionally with the anodizing voltage. And the pores tend to be initiated close to the alumina stripes. These phenomena can be ascribed to the electric field distribution in the alumina barrier layer caused by the geometric structure of the aluminum surface.

  9. Oxidation Behavior of α-alumina Scales on Fe-Al Diffusion Coating of China Activation Martensitic Steel(CLAM)

    Institute of Scientific and Technical Information of China (English)

    ZHAN; Qin; YANG; Hong-guang; ZHAO; Wei-wei; YUAN; Xiao-ming; ZHU; Xin-xin

    2013-01-01

    It is well known thatα-Al2O3 phase has stable,high permeation reduction factor(PRF)and good resistance performance in liquid LiPb,which is considered as the reference tritium permeation barriercoating in future fusion reactor.In order to study the formation mechanism of stableα-Al2O3 scales on fusion structure material,the oxidation behavior of Fe-Al diffusion coating on China Low Activation

  10. Large Scale Laser Crystallization of Solution-based Alumina-doped Zinc Oxide (AZO) Nanoinks for Highly Transparent Conductive Electrode

    Science.gov (United States)

    Nian, Qiong; Callahan, Michael; Saei, Mojib; Look, David; Efstathiadis, Harry; Bailey, John; Cheng, Gary J.

    2015-10-01

    A new method combining aqueous solution printing with UV Laser crystallization (UVLC) and post annealing is developed to deposit highly transparent and conductive Aluminum doped Zinc Oxide (AZO) films. This technique is able to rapidly produce large area AZO films with better structural and optoelectronic properties than most high vacuum deposition, suggesting a potential large-scale manufacturing technique. The optoelectronic performance improvement attributes to UVLC and forming gas annealing (FMG) induced grain boundary density decrease and electron traps passivation at grain boundaries. The physical model and computational simulation developed in this work could be applied to thermal treatment of many other metal oxide films.

  11. Challenges and Strategies in the Synthesis of Mesoporous Alumina Powders and Hierarchical Alumina Monoliths

    Directory of Open Access Journals (Sweden)

    Anne Galarneau

    2012-02-01

    Full Text Available A new rapid, very simple and one-step sol-gel strategy for the large-scale preparation of highly porous γ-Al2O3 is presented. The resulting mesoporous alumina materials feature high surface areas (400 m2 g−1, large pore volumes (0.8 mL g−1 and the ��-Al2O3 phase is obtained at low temperature (500 °C. The main advantages and drawbacks of different preparations of mesoporous alumina materials exhibiting high specific surface areas and large pore volumes such as surfactant-nanostructured alumina, sol-gel methods and hierarchically macro-/mesoporous alumina monoliths have been analyzed and compared. The most reproducible synthesis of mesoporous alumina are given. Evaporation-Induced Self-Assembly (EISA is the sole method to lead to nanostructured mesoporous alumina by direct templating, but it is a difficult method to scale-up. Alumina featuring macro- and mesoporosity in monolithic shape is a very promising material for in flow applications; an optimized synthesis is described.

  12. New science at the European Spallation Source

    Energy Technology Data Exchange (ETDEWEB)

    Finney, J.L. [University Coll., London (United Kingdom). Dept. of Physics and Astronomy

    1996-05-01

    The European Spallation Source is a trans-European project aimed at the ultimate construction of a next-generation pulsed spallation neutron source that will deliver 30 times the beam power of ISIS. The reference design for the proposed source has been set, and work is in progress to develop an updated scientific case for the construction of the source early in the next century. Together with improvements in instrumentation, effective flux gains of over two orders of magnitude are likely in some areas, opening up major new opportunities for the exploitation of neutron studies in fundamental, strategic, and applied science. (author)

  13. Management of Tritium in European Spallation Source

    DEFF Research Database (Denmark)

    Ene, Daniela; Andersson, Kasper Grann; Jensen, Mikael

    2015-01-01

    The European Spallation Source (ESS) will produce tritium via spallation and activation processes during operational activities. Within the location of ESS facility in Lund, Sweden site it is mandatory to demonstrate that the management strategy of the produced tritium ensures the compliance...... with the country regulation criteria. The aim of this paper is to give an overview of the different aspects of the tritium management in ESS facility. Besides the design parameter study of the helium coolant purification system of the target the consequences of the tritium releasing into the environment were also...

  14. Material selection for spallation neutron source windows

    Energy Technology Data Exchange (ETDEWEB)

    Sordo, F. [ETSII/Universidad Politecnica de Madrid, J. Gutierrez Abascal, 2-28006 Madrid (Spain); Abanades, A. [ETSII/Universidad Politecnica de Madrid, J. Gutierrez Abascal, 2-28006 Madrid (Spain)], E-mail: abanades@etsii.upm.es; Lafuente, A.; Martinez-Val, J.M. [ETSII/Universidad Politecnica de Madrid, J. Gutierrez Abascal, 2-28006 Madrid (Spain); Perlado, M. [Instituto de Fusion Nuclear (DENIM)/ETSII/Universidad Politecnica, Madrid, J. Gutierrez Abascal, 2-28006 Madrid (Spain)

    2009-11-15

    High performance neutron sources are being proposed for many scientific and industrial applications, ranging from material studies, hybrid reactors and transmutation of nuclear wastes. In the case of transmutation of nuclear wastes, accelerator driven systems (ADS) are considered as one of the main technical options for such purpose. In ADS a high performance spallation neutron source becomes an essential element for its operation and control. This spallation source must fulfil very challenging nuclear and thermo-mechanical requirements, because of the high neutron rates needed in ADS. The material selection for this key component becomes of paramount importance, particularly the source window that separates the vacuum accelerator tube from the spallation material where the accelerated protons impinge. In this paper, an integral analysis of spallation sources is done, taking as a reference the projects in this field proposal in the framework of European projects. Our analysis and calculations show that titanium and vanadium alloys are more suitable than steel as structural material for an industrial ADS beam window, mostly due to its irradiation damage resistance.

  15. Reuse of activated alumina

    Energy Technology Data Exchange (ETDEWEB)

    Hobensack, J.E. [Martin Marietta Energy Systems, Inc., Piketon, OH (United States)

    1991-12-31

    Activated alumina is used as a trapping media to remove trace quantities of UF{sub 6} from process vent streams. The current uranium recovery method employs concentrated nitric acid which destroys the alumina pellets and forms a sludge which is a storage and disposal problem. A recently developed technique using a distilled water rinse followed by three dilute acid rinses removes on average 97% of the uranium, and leaves the pellets intact with crush strength and surface area values comparable with new material. Trapping tests confirm the effectiveness of the recycled alumina as UF{sub 6} trapping media.

  16. Fabrication of porous alumina templates with a large-scale tunable interpore distance in a H2C2O4-C2H5OH-H2O solution

    Institute of Scientific and Technical Information of China (English)

    LI Yi; LING ZhiYuan; WANG JinChi; GHEN ShuoShuo; HU Xing; HE XinHua

    2008-01-01

    Highly ordered porous alumina templates with a large-scale tunable interpore distance (100-445 nm) have been successfully fabricated under an electric field of 40-180 V by modifying oxalic acid solution with adequate alcohol. The results under our experimental conditions show that the phenomena of burning and breakdown during the high-field anodization process can be avoided by adding a proper amount of alcohol to the oxalic acid solution, An excellent linear relationship between interpore dis-tance and anodization voltage is obtained under 40-170 V, and the maximum anodization voltage that could be used to avoid burning and breakdown is 180 V.

  17. Study of the molybdenum retention in alumina; Estudio de la retencion de molibdeno en alumina

    Energy Technology Data Exchange (ETDEWEB)

    Wilkinson, Maria V.; Mondino, Angel V.; Manzini, Alberto [Comision Nacional de Energia Atomica, Buenos Aires (Argentina). Centro Atomico Ezeiza. Radioquimica y Quimica de las Radiaciones

    2002-07-01

    The Argentine National Atomic Energy Commission routinely produces {sup 99} Mo by fission of highly enriched uranium contained in targets irradiated in RA-3 reactor. The current process begins with the dissolution of the irradiated target in a basic media, considering the possibility of changing the targets, it could be convenient to dissolve them in acid media. The use of alumina as a first separation step in acid dissolution processes is already known although it is necessary to determine both the type of alumina to be used and the separation conditions. The study of molybdenum retention in alumina was performed at laboratory scale, using Mo-99 as radiotracer. Different kinds of alumina were tried, varying charge solution acidity. Influence of uranium concentration in the loading solution on molybdenum retention was also studied. (author)

  18. Thermal-hydraulic analysis of LBE spallation target for accelerator-driven systems

    Indian Academy of Sciences (India)

    Aniseh Ahmed Atef Abdalla; Jiyang Yu; Yongwel Yang

    2013-01-01

    In an accelerator-driven subcritical system (ADS), a high-performance spallation neutron source is used to feed the subcritical reactor. Neutron generation depends on the proton beam intensity. If the beam intensity is increased by a given factor, the number of generated neutrons will increase. The mechanism yielding a high rate of neutron production per energy is the spallation process, and this mechanism produces very high-energy deposition in the spallation target material. Producing a high rate of neutrons is accompanied by creation of problems of decay heat cooling and radiological protection. As a first step in designing a full-scale industrial ADS, a small-scale experimental ADS, which is similar to the European experimental ADS (XADS) is analysed. The analysis presented in this paper is based on lead–bismuth eutectic (LBE) cooled XADS-type experimental reactors, designed during the European experimental (PDS-XADS) project. Computational fluid dynamics analysis has been carried out for the spallation target. Steady-state behaviour and shear stress transport turbulence model with the automatic wall treatment were applied in the present analysis.

  19. Thermal features of spallation window targets

    Energy Technology Data Exchange (ETDEWEB)

    Abanades, Alberto; Sordo, Fernando; Lafuente, Antonio [E.T.S. Industriales, Madrid Polytechnic University, UPM, J. Gutierrez Abascal, 2, 28006 Madrid (Spain); Martinez-Val, Jose M. [E.T.S. Industriales, Madrid Polytechnic University, UPM, J. Gutierrez Abascal, 2, 28006 Madrid (Spain)], E-mail: mval@etsii.upm.es

    2008-07-15

    The spallation process is a cascade of nuclear reactions induced by medium-energy hadrons, notably protons, which impinge in a suitable material as accelerated particles. A main outcome of that cascade is a shower of medium and high-energy neutrons, which can be used for irradiation purposes or to feed a subcritical reactor. The neutron production is accompanied by the generation of a broad set of radioactive products, which presents specific problems of radiological protection and decay heat removal. The nominal heat load is another point of concern, because of the very high power densities produced in the proton beam energy deposition in the interaction region. All these phenomena are taken into account in this paper in order to set up an integral and coherent task flowchart in order to guide the design of spallation sources.

  20. INJECTION CHOICE FOR SPALLATION NEUTRON SOURCE RING.

    Energy Technology Data Exchange (ETDEWEB)

    WEI,J.; BEEBE-WANG,J.; BLASKIEWICZ,M.; BRODOWSKI,J.; FEDOTOV,A.; GARDNER,C.; LEE,Y.Y.; RAPARIA,D.; DANILOV,V.; HOLMES,J.; PRIOR,C.; REES,G.; MACHIDA,S.

    2001-06-18

    Injection is key in the low-loss design of high-intensity proton facilities like the Spallation Neutron Source (SNS). During the design of both the accumulator and the rapid-cycling-synchrotron version of the SNS, extensive comparison has been made to select injection scenarios that satisfy SNS's low-loss design criteria. This paper presents issues and considerations pertaining to the final choice of the SNS injection systems.

  1. Linac-driven spallation-neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Jason, A.J.

    1995-05-01

    Strong interest has arisen in accelerator-driven spallation-neutron sources that surpass existing facilities (such as ISIS at Rutherford or LANSCE at Los Alamos) by more than an order of magnitude in beam power delivered to the spallation target. The approach chosen by Los Alamos (as well as the European Spallation Source) provides the full beam energy by acceleration in a linac as opposed to primary acceleration in a synchrotron or other circular device. Two modes of neutron production are visualized for the source. A short-pulse mode produces 1 MW of beam power (at 60 pps) in pulses, of length less than 1 ms, by compression of the linac macropulse through multi-turn injection in an accumulator ring. A long-pulse mode produces a similar beam power with 1-ms-long pulses directly applied to a target. This latter mode rivals the performance of existing reactor facilities to very low neutron energies. Combination with the short-pulse mode addresses virtually all applications.

  2. Spallation reactions studied with 4-detector arrays

    Indian Academy of Sciences (India)

    J Galin

    2001-07-01

    Recently there has been a renewed interest in the study of spallation reactions in basic nuclear physics as well as in potential applications. Spallation reactions induced by light projectiles (protons, antiprotons, pions, etc.) in the GeV range allow the formation of hot nuclei which do not suffer the collective excitations (compression, rotation, deformation) unavoidable when using massive projectiles. Such nuclei provide an ideal testbench for probing their decay as a function of excitation energy. In these investigations, 4-detector arrays for charged particles and neutrons play a major role in the event-by-event sorting according to the excitation energy of the nucleus. Spallation reactions induced on heavy nuclei allow the conversion of the incident GeV proton into several tens of evaporated neutrons. The neutron production in thick targets has been investigated in great detail thanks to the use of high efficiency neutron detector arrays. When scattered on samples of inert or biological materials, these neutrons can be used to study details of the material structure. They could also be utilized for the transmutation of long-lived nuclear wastes or for the feeding of sub-critical nuclear reactors. The role of different types of multi-detector arrays is highlighted in this paper. Several references are also given for different uses of high efficiency neutron detectors in other contexts.

  3. Prototype Spallation Neutron Source Rotating Target Assembly Final Test Report

    Energy Technology Data Exchange (ETDEWEB)

    McManamy, Thomas J [ORNL; Graves, Van [Oak Ridge National Laboratory (ORNL); Garmendia, Amaia Zarraoa [IDOM Bilbao; Sorda, Fernando [ESS Bilbao; Etxeita, Borja [IDOM Bilbao; Rennich, Mark J [ORNL

    2011-01-01

    A full-scale prototype of an extended vertical shaft, rotating target assembly based on a conceptual target design for a 1 to 3-MW spallation facility was built and tested. Key elements of the drive/coupling assembly implemented in the prototype include high integrity dynamic face seals, commercially available bearings, realistic manufacturing tolerances, effective monitoring and controls, and fail-safe shutdown features. A representative target disk suspended on a 3.5 meter prototypical shaft was coupled with the drive to complete the mechanical tests. Successful operation for 5400 hours confirmed the overall mechanical feasibility of the extended vertical shaft rotating target concept. The prototype system showed no indications of performance deterioration and the equipment did not require maintenance or relubrication.

  4. Improvement in nanoscale contact resistance of alumina

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharya, Manjima; Chakraborty, Riya; Mandal, Ashok Kumar [CSIR - Central Glass and Ceramic Research Institute, Kolkata (India); Dey, Arjun [CSIR - Central Glass and Ceramic Research Institute, Kolkata (India); ISRO Satellite Centre, Thermal Systems Group, Bangalore (India); Mukhopadhyay, Anoop Kumar [CSIR - Central Glass and Ceramic Research Institute, Kolkata (India); Central Glass and Ceramic Research Institute, Kolkata 32 (India)

    2012-06-15

    In all contact-related applications such as the wear-resistant inserts, biomedical implants, high strain rate impact-resistant plates, etc., nanohardness, i.e. the intrinsic contact resistance at the nano scale, plays a major role. In spite of the wealth of literature, the studies on nanohardness of dense, coarse-grain alumina ceramics which represent many commercial varieties; have reasonably good hardness at the macro scale and characteristically exhibit R-curve behaviour, are far from significant. Here, to the best of our knowledge, we report for the first time the experimental observations of the increase in intrinsic contact resistance at the nano scale with the loading rate applied to a high-density ({proportional_to}95 % of theoretical) coarse-grain ({proportional_to}20 {mu}m) alumina ceramics. These observations were explained in terms of the initiation of nanoscale plasticity and maximum shear stress generated just underneath the nanoindenter. (orig.)

  5. Muon-induced spallation backgrounds in DUNE

    Science.gov (United States)

    Zhu, Guanying; Li, Shirley; Beacom, John

    2017-01-01

    Galactic supernovae are rare, just a few per century, so it is important to be prepared. If we are, then the long-baseline detector DUNE could detect thousands of events, compared to the tens from SN 1987A. An important question is backgrounds from muon-induced spallation reactions. We simulate particle energy-loss processes in liquid argon, and compare relevant isotope yields with those in the water-Cherenkov detector SuperK. Our approach will help optimize the design of DUNE and further benefit the study of supernova neutrinos. GZ, SWL, and JFB are supported by NSF Grant PHY-1404311.

  6. Fundamental physics possibilities at the European Spallation Source

    DEFF Research Database (Denmark)

    Klinkby, Esben Bryndt; Soldner, Torsten

    2016-01-01

    The construction of the European Spallation Source ESS is ongoing in Lund, Sweden. This new high power spallation source with its long-pulse structure opens up new possibilities for fundamental physics experiments. This paper focusses on two proposals for fundamental physics at the ESS: The ANNI...

  7. Fundamental physics possibilities at the European Spallation Source

    DEFF Research Database (Denmark)

    Klinkby, Esben Bryndt; Soldner, Torsten

    The construction of the European Spallation Source ESS is ongoing in Lund, Sweden. This new high power spallation source with its long-pulse structure opens up new possibilities for fundamental physics experiments. This paper focusses on two proposals for fundamental physics at the ESS: The ANNI...

  8. Fundamental physics possibilities at the European Spallation Source

    DEFF Research Database (Denmark)

    Klinkby, Esben Bryndt; Batkov, Konstantin; Mezei, Ferenc;

    2016-01-01

    The construction of the European Spallation has recently started in Lund, Sweden.In addition to the neutron scattering instruments the ESS is designed to serve, the constructionof a new spallation source opens up new possibilities for fundamental physics experiments. Inthis paper some of the poss...

  9. QGSM development for spallation reactions modeling

    Science.gov (United States)

    Baznat, M. I.; Chigrinov, S. E.; Gudima, K. K.

    2012-12-01

    The growing interest in spallation neutron sources, accelerator-driven systems, R&D of rare isotope beams, and development of external beam radiation therapy necessitated the improvement of nuclear reaction models for both stand-alone codes for the analysis of nuclear reactions and event generators within the Monte Carlo transport systems for calculations of interactions of high-energy particles with matter in a wide range of energy and in arbitrary 3D geometry of multicomponent targets. The exclusive approach to the description of nuclear reactions is the most effective for detailed calculation of inelastic interactions with atomic nuclei. It provides the correct description of particle production, single- and double-differential spectra, recoil, and fission product yields. This approach has been realized in the Quark Gluon String Model (QGSM) for nuclear reactions induced by photons, hadrons, and high energy heavy ions. In this article, improved versions of the QGSM model and a corresponding code have been developed tested and bench marked against experimental data for neutron production in spallation reactions on thin and thick targets in the energy range from a few MeV to several GeV/nucleon.

  10. Spallation studies on shock loaded uranium

    Energy Technology Data Exchange (ETDEWEB)

    Tonks, D.L.; Hixson, R.; Gustavsen, R.L.; Vorthman, J.E.; Kelly, A.; Zurek, A.K.; Thissel, W.R. [Los Alamos National Lab., NM (United States)

    1997-12-31

    Uranium samples at two different purity levels were used for spall strength measurements at three different stress levels. A 50 mm single-stage gas-gun was used to produce planar impact conditions using Z-cut quartz impactors. Samples of depleted uranium were taken from very high purity material and from material that had 300 ppm of carbon added. A pair of shots was done for each impact strength, one member of the pair with VISAR diagnostics and the second with soft recovery for metallographical examination. A series of increasing final stress states were chosen to effectively freeze the microstructural damage at three places in the development to full spall separation. This allowed determination of the dependence of spall mechanisms on stress level and sample purity. This report will discuss both the results of the metallurgical examination of soft recovered samples and the modeling of the free surface VISAR data. The micrographs taken from the recovered samples show brittle cracking as the spallation failure mechanism. Deformation induced twins are plentiful and obviously play a role in the spallation process. The twins are produced in the initial shock loading and, so, are present already before the fracture process begins. The 1 d characteristics code CHARADE has been used to model the free surface VISAR data.

  11. QGSM development for spallation reactions modeling

    Directory of Open Access Journals (Sweden)

    Gudima K.K.

    2012-12-01

    Full Text Available The growing interest in spallation neutron sources, accelerator-driven systems, R&D of rare isotope beams, and development of external beam radiation therapy necessitated the improvement of nuclear reaction models for both stand-alone codes for the analysis of nuclear reactions and event generators within the Monte Carlo transport systems for calculations of interactions of high-energy particles with matter in a wide range of energy and in arbitrary 3D geometry of multicomponent targets. The exclusive approach to the description of nuclear reactions is the most effective for detailed calculation of inelastic interactions with atomic nuclei. It provides the correct description of particle production, single- and double-differential spectra, recoil, and fission product yields. This approach has been realized in the Quark Gluon String Model (QGSM for nuclear reactions induced by photons, hadrons, and high energy heavy ions. In this article, improved versions of the QGSM model and a corresponding code have been developed tested and bench marked against experimental data for neutron production in spallation reactions on thin and thick targets in the energy range from a few MeV to several GeV/nucleon.

  12. Impact loading of an aluminum/alumina composite

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, J.N.; Hixson, R.S.; Gray, G.T. III

    1994-02-01

    The combined demands of increased strength and reduced weight in modern dynamic structural applications require improved understanding of composite materials subject to impact conditions. In order to isolate and identify individual contributions to composite material behavior under these conditions, an experimental and theoretical program was undertaken to examine dynamic behavior of an aluminum/alumina composite consisting of a 6061-T6 aluminum matrix containing elastic, spherical Al{sub 2}O{sub 3} inclusions (10 percent by volume, average diameter {approximately}25 microns). Parallel impact experiments are conducted on these composites and on pure 6061-T6 aluminum samples. This combination provides a direct and immediate qualitative picture of the effect of Al{sub 2}O{sub 3} inclusions the dynamic response of the composite in compression, release, and spallation. Additional experimental information is provided by post-shock reload tests of shock-recovered samples at quasi-static and intermediate strain rates.

  13. Deformation Behaviour of Coarse Grain Alumina under Shock Loading

    Science.gov (United States)

    Gupta, Satish

    2013-06-01

    To develop better understanding of the shock wave induced deformation behavior of coarse grain alumina ceramics, and for measurement of its Hugoniot Elastic Limit (HEL), in-situ and recovery gas gun experiments have been carried out on coarse grain alumina (grain size ~ 10 μm), prepared in the form of discs (>99.9% TMD) by pressure-less sintering of alpha alumina powder at 1583 K. The HEL value of 1.9 GPa has been determined from the kink in the pressure history recorded using piezoresistance gauge and also from the free surface velocity history of the sample shocked to 9 GPa. The nano-indentation measurements on the alumina samples shocked to 6.5 GPa showed hardness value 15% lower than 21.3 GPa for unshocked alumina, and strong Indentation Size Effect (ISE); the hardness value was still lower and the ISE was stronger for the sample shocked to 12 GPa. The XRD measurements showed reduced particle size and increased microstrains in the shocked alumina fragments. SEM, FESEM and TEM measurements on shock treated samples showed presence of grain localized micro- and nano-scale deformations, micro-cleavages, grain-boundary microcracks, extensive shear induced deformations, and localized micro-fractures, etc. These observations led to the development of a qualitative model for the damage initiation and its subsequent growth mechanisms in shocked alumina. The work performed in collaboration with K.D. Joshi of BARC and A.K. Mukhopadhyay of CGCRI.

  14. Estimation of thermochemical behavior of spallation products in mercury target

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Kaoru; Kaminaga, Masanori; Haga, Katsuhiro; Kinoshita, Hidetaka; Aso, Tomokazu; Teshigawara, Makoto; Hino, Ryutaro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2002-02-01

    In order to examine the radiation safety of a spallation mercury target system, especially source term evaluation, it is necessary to clarify the chemical forms of spallation products generated by spallation reaction with proton beam. As for the chemical forms of spallation products in mercury that involves large amounts of spallation products, these forms were estimated by using the binary phase diagrams and the thermochemical equilibrium calculation based on the amounts of spallation product. Calculation results showed that the mercury would dissolve Al, As, B, Be, Bi, C, Co, Cr, Fe, Ga, Ge, Ir, Mo, Nb, Os, Re, Ru, Sb, Si, Ta, Tc, V and W in the element state, and Ag, Au, Ba, Br, Ca, Cd, Ce, Cl, Cs, Cu, Dy, Er, Eu, F, Gd, Hf, Ho, I, In, K, La, Li, Lu, Mg, Mn, Na, Nd, Ni, O, Pb, Pd, Pr, Pt, Rb, Rh, S, Sc, Se, Sm, Sn, Sr, Tb, Te, Ti, Tl, Tm, Y, Yb, Zn and Zr in the form of inorganic mercury compounds. As for As, Be, Co, Cr, Fe, Ge, Ir, Mo, Nb, Os, Pt, Re, Ru, Se, Ta, V, W and Zr, precipitation could be occurred when increasing the amounts of spallation products with operation time of the spallation target system. On the other hand, beryllium-7 (Be-7), which is produced by spallation reaction of oxygen in the cooling water of a safety hull, becomes the main factor of the external exposure to maintain the cooling loop. Based on the thermochemical equilibrium calculation to Be-H{sub 2}O binary system, the chemical forms of Be in the cooling water were estimated. Then the Be could exist in the form of cations such as BeOH{sup +}, BeO{sup +} and Be{sup 2+} under the condition of less than 10{sup -8} of the Be mole fraction in the cooling water. (author)

  15. Determination of spallation neutron flux through spectral adjustment techniques

    Science.gov (United States)

    Mosby, M. A.; Engle, J. W.; Jackman, K. R.; Nortier, F. M.; Birnbaum, E. R.

    2016-08-01

    The Los Alamos Isotope Production Facility (IPF) creates medical isotopes using a proton beam impinged on a target stack. Spallation neutrons are created in the interaction of the beam with target. The use of these spallation neutrons to produce additional radionuclides has been proposed. However, the energy distribution and magnitude of the flux is not well understood. A modified SAND-II spectral adjustment routine has been used with radioactivation foils to determine the differential neutron fluence for these spallation neutrons during a standard IPF production run.

  16. Determination of spallation neutron flux through spectral adjustment techniques

    Energy Technology Data Exchange (ETDEWEB)

    Mosby, M.A., E-mail: mosbym@lanl.gov; Engle, J.W.; Jackman, K.R.; Nortier, F.M.; Birnbaum, E.R.

    2016-08-15

    The Los Alamos Isotope Production Facility (IPF) creates medical isotopes using a proton beam impinged on a target stack. Spallation neutrons are created in the interaction of the beam with target. The use of these spallation neutrons to produce additional radionuclides has been proposed. However, the energy distribution and magnitude of the flux is not well understood. A modified SAND-II spectral adjustment routine has been used with radioactivation foils to determine the differential neutron fluence for these spallation neutrons during a standard IPF production run.

  17. Status of the AUSTRON spallation project

    Science.gov (United States)

    Rauch, H.; Regler, M.; Weber, H.

    2000-03-01

    The characteristic parameters of the present version of the planned AUSTRON neutron spallation source are: (a) 10 Hz repetition rate at the target, (b) 500 kW average beam power, (c) 1.6 GeV proton energy and (d) strongly dedicated to cold neutron research. The machine can be built based on existing techniques and would provide a performance gain between 3 and 10 compared to existing installations. Progress has been made in the planning of the instrumentation where an improved standard instrumentation and several new systems have been designed and evaluated by an international group of neutron scientists. A clean room area with vibration, temperature and humidity control provides new possibilities for neutron optics, neutron reflectometry and nuclear orientation experiments. A proposed magnetic focusing line with an active energy transfer system indicates the capability to achieve a further intensity gain by a factor of 10. The status of the ongoing internationalization process will be reported as well.

  18. Measurements of neutron spallation cross section. 2

    Energy Technology Data Exchange (ETDEWEB)

    Kim, E.; Nakamura, T. [Tohoku Univ., Sendai (Japan). Cyclotron and Radioisotope Center; Imamura, M.; Nakao, N.; Shibata, S.; Uwamino, Y.; Nakanishi, N.; Tanaka, Su.

    1997-03-01

    Neutron spallation cross section of {sup 59}Co(n,xn){sup 60-x}Co, {sup nat}Cu(n,sp){sup 56}Mn, {sup nat}Cu(n,sp){sup 58}Co, {sup nat}Cu(n,xn){sup 60}Cu, {sup nat}Cu(n,xn){sup 61}Cu and {sup nat}Cu(n,sp){sup 65}Ni was measured in the quasi-monoenergetic p-Li neutron fields in the energy range above 40 MeV which have been established at three AVF cyclotron facilities of (1) INS of Univ. of Tokyo, (2) TIARA of JAERI and (3) RIKEN. Our experimental data were compared with the ENDF/B-VI high energy file data by Fukahori and the calculated cross section data by Odano. (author)

  19. Radiochemical aspects of liquid mercury spallation targets

    CERN Document Server

    Neuhausen, Joerg; Eichler, Bernd; Eller, Martin; Horn, Susanne; Schumann, Dorothea; Stora, Thierry

    2012-01-01

    Liquid metal spallation targets using mercury as target material are used in state-of-the-art high power pulsed neutron sources that have been constructed in the USA and Japan within the last decade. Similar target concepts were also proposed for next generation ISOL, beta-beam and neutrino facilities. A large amount of radioactivity will be induced in the liquid metal during operation caused by the interaction of the target material with the intense proton beam. This radioactivity - carried by a wide range of radioisotopes of all the elements of the periodic table from hydrogen up to thallium - must be considered for the assessment of safe operation and maintenance procedures as well as for a final disposal of the used target material and components. This report presents an overview on chemical investigations performed in our laboratory that deal with the behavior of radionuclides in proton irradiated mercury samples. The solubility of elements in mercury was calculated using thermodynamical data obtained by...

  20. Role of multifragmentation in spallation reactions

    CERN Document Server

    Botvina, A S

    2008-01-01

    In nuclear reactions induced by hadrons and ions of high energies, nuclei can disintegrate into many fragments during a short time (~100 fm/c). This phenomenon known as nuclear multifragmentation was under intensive investigation last 20 years. It was established that multifragmentation is an universal process taking place in all reactions when the excitation energy transferred to nuclei is high enough, more than 3 MeV per nucleon, independently on the initial dynamical stage of the reactions. Very known compound nucleus decay processes (sequential evaporation and fission), which are usual for low energies, disappear and multifragmentation dominates at high excitation energy. For this reason, calculation of multifragmentation must be carried on in all cases when production of highly excited nuclei is expected, including spallation reactions. From the other hand, one can consider multifragmentation as manifestation of the liquid-gas phase transition in finite nuclei. This gives way for studying nuclear matter ...

  1. Superhydrophobic alumina surface based on stearic acid modification

    Energy Technology Data Exchange (ETDEWEB)

    Feng Libang, E-mail: lepond@hotmail.com [School of Mechatronic Engineering, Lanzhou Jiaotong University, Lanzhou 730070 (China); Zhang Hongxia; Mao Pengzhi; Wang Yanping; Ge Yang [School of Mechatronic Engineering, Lanzhou Jiaotong University, Lanzhou 730070 (China)

    2011-02-15

    A novel superhydrophobic alumina surface is fabricated by grafting stearic acid layer onto the porous and roughened aluminum film. The chemical and phase structure, morphology, and the chemical state of the atoms at the superhydrophobic surface were investigated by techniques as FTIR, XRD, FE-SEM, and XPS, respectively. Results show that a super water-repellent surface with a contact angle of 154.2{sup o} is generated. The superhydrophobic alumina surface takes on an uneven flowerlike structure with many nanometer-scale hollows distribute in the nipple-shaped protrusions, and which is composed of boehmite crystal and {gamma}-Al{sub 2}O{sub 3}. Furthermore, the roughened and porous alumina surface is coated with a layer of hydrophobic alkyl chains which come from stearic acid molecules. Therefore, both the roughened structure and the hydrophobic layer endue the alumina surface with the superhydrophobic behavior.

  2. The European scene regarding spallation neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, G.S. [Paul Scherrer Institut, Villigen (Austria)

    1996-06-01

    In Europe, a short pulse spallation neutron source, ISIS, has been operating for over 10 years, working its way up to a beam power level of 200 kW. A continuous source, SINQ, designed for a beam power of up to 1 MW, is scheduled to start operating at the end of 1996, and a detailed feasibility study has been completed for a 410 kW short pulse source, AUSTRON. Each of these sources seems to have settled for a target concept which is at or near the limits of its feasibility: The ISIS depleted uranium plate targets, heavy water cooled and Zircaloy clad, have so far not shown satisfactory service time and operation is likely to continue with a Ta-plate target, which, in the past has been used successfully for the equivalent of one full-beam-year before it was taken out of service due to degrading thermal properties. SINQ will initially use a rod target, made of Zircaloy only, but plans exist to move on to clad lead rods as quickly as possible. Apart from the not yet explored effect of hydrogen and helium production, there are also concerns about the generation of 7-Be in the cooling water from the spallation of oxygen, which might result in undesirably high radioactivity in the cooling plant room. A Liquid metal target, also under investigation for SINQ, would not only reduce this problem to a level of about 10 %, but would also minimize the risk of radiolytic corrosion in the beam interaction zone. Base on similar arguments, AUSTRON has been designed for edge cooled targets, but thermal and stress analyses show, that this concept is not feasible at higher power levels.

  3. Strain rate effects for spallation of concrete

    Directory of Open Access Journals (Sweden)

    Häussler-Combe Ulrich

    2015-01-01

    Full Text Available Appropriate triaxial constitutive laws are the key for a realistic simulation of high speed dynamics of concrete. The strain rate effect is still an open issue within this context. In particular the question whether it is a material property – which can be covered by rate dependent stress strain relations – or mainly an effect of inertia is still under discussion. Experimental and theoretical investigations of spallation of concrete specimen in a Hopkinson Bar setup may bring some evidence into this question. For this purpose the paper describes the VERD model, a newly developed constitutive law for concrete based on a damage approach with included strain rate effects [1]. In contrast to other approaches the dynamic strength increase is not directly coupled to strain rate values but related to physical mechanisms like the retarded movement of water in capillary systems and delayed microcracking. The constitutive law is fully triaxial and implemented into explicit finite element codes for the investigation of a wide range of concrete structures exposed to impact and explosions. The current setup models spallation experiments with concrete specimen [2]. The results of such experiments are mainly related to the dynamic tensile strength and the crack energy of concrete which may be derived from, e.g., the velocity of spalled concrete fragments. The experimental results are compared to the VERD model and two further constitutive laws implemented in LS-Dyna. The results indicate that both viscosity and retarded damage are required for a realistic description of the material behaviour of concrete exposed to high strain effects [3].

  4. Mechanism of spallation in platinum aluminide/electron beam physical vapor-deposited thermal barrier coatings

    Energy Technology Data Exchange (ETDEWEB)

    Gell, M.; Vaidyanathan, K.; Barber, B.; Cheng, J.; Jordan, E. [Univ. of Connecticut, Storrs, CT (United States)

    1999-02-01

    The spallation failure of a commercial thermal barrier coating (TBC), consisting of a single-crystal RENE N5 superalloy, a platinum aluminide (Pt-Al) bond coat, and an electron beam-deposited 7 wt pct yttria-stabilized zirconia ceramic layer (7YSZ), was studied following cyclic furnace testing. In the uncycled state and prior to deposition of the ceramic, the Pt-Al bond-coat surface contains a cellular network of ridges corresponding to the underlying bond-coat grain-boundary structure. With thermal cycling, the ridges and associated grain boundaries are the sites of preferential oxidation and cracking, which results in the formation of cavities that are partially filled with oxide. Using a fluorescent penetrant dye in conjunction with a direct-pull test, it is shown that, when specimens are cycled to about 80 pct of life, these grain-boundary regions show extensive debonding. The roles of oxidation and cyclic stress in localized grain boundary region spallation are discussed. The additional factors leading to large-scale TBC spallation are described.

  5. Benchmarking Geant4 for spallation neutron source calculations

    Science.gov (United States)

    DiJulio, Douglas D.; Batkov, Konstantin; Stenander, John; Cherkashyna, Nataliia; Bentley, Phillip M.

    2016-09-01

    Geant4 is becoming increasingly used for radiation transport simulations of spallation neutron sources and related components. Historically, the code has seen little usage in this field and it is of general interest to investigate the suitability of Geant4 for such applications. For this purpose, we carried out Geant4 calculations based on simple spallation source geometries and also with the the European Spallation Source Technical Design Report target and moderator configuration. The results are compared to calculations performed with the Monte Carlo N- Particle extended code. The comparisons are carried out over the full spallation neutron source energy spectrum, from sub-eV energies up to thousands of MeV. Our preliminary results reveal that there is generally good agreement between the simulations using both codes. Additionally, we have also implemented a general weight-window generator for Geant4 based applications and present some results of the method applied to the ESS target model.

  6. Proceedings of the international workshop on spallation materials technology

    Energy Technology Data Exchange (ETDEWEB)

    Mansur, L.K.; Ullmaier, H. [comps.

    1996-10-01

    This document contains papers which were presented at the International Workshop on Spallation Materials Technology. Topics included: overviews and thermal response; operational experience; materials experience; target station and component design; particle transport and damage calculations; neutron sources; and compatibility.

  7. Effects of Platinum Additions and Sulfur Impurities on the Microstructure and Scale Adhesion Behavior of Single-Phase CVD Aluminide Bond Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Cooley, K.M.; Haynes, J.A.; Lee, W.Y.; Pint, B.A.; Wright, I.G.; Zhang, Y.

    1999-02-28

    The adhesion of alumina scales to aluminide bond coats is a life-limiting factor for some advanced thermal barrier coating systems. This study investigated the effects of aluminide bond coat sulfur and platinum contents on alumina scale adhesion and coating microstructural evolution during isothermal and cyclic oxidation testing at 1150 C. Low-sulfur NiAl and NiPtAl bond coats were fabricated by chemical vapor deposition (CVD). Lowering the sulfur contents of CVD NiAl bond coatings significantly improved scale adhesion, but localized scale spallation eventually initiated along coating grain boundaries. Further improvements in scale adhesion were obtained with Pt additions. The observed influences of Pt additions included: (1) mitigation of the detrimental effects of high sulfur levels, (2) drastic reductions in void growth along the scale-metal interface, (3) alteration of the oxide-metal interface morphology, and (4) elimination of Ta-rich oxides in the Al{sub 2}O{sub 3} scales during thermal cycling. The results of this study also suggested that the microstructure (especially the grain size) of CVD aluminide bond coatings plays a significant role in scale adhesion.

  8. Deexcitation Modes in Spallation Nuclear Reactions

    Science.gov (United States)

    Velasco, F. G.; Guzmán, F.; Rodriguez, O.; Tumbarell, O.; Souza, D. A.; Samana, A. R.; Andrade-II, E.; Bernal Castillo, J. L.; Deppman, A.

    2016-08-01

    Spallation nuclear reactions in the range of 0.2 to 1.2 GeV are studied using the CRISP code. A new approach for the deexcitation stage of the compound nucleus was introduced. For the calculations of the level densities, this approach is based on the Back-shifted Fermi gas model (BSFG), which takes into account pairing effects and shell corrections, whereas the calculation of the fission barriers were performed by means of the Extended Thomas-Fermi plus Strutinsky Integral (ETFSI) method, which is a high-speed approximation to the Hartree-Fock method with pairing correlations treated as in the usual BCS plus blocking approach. This procedure is more appropriate to calculate level densities for exotic nuclei. Satisfactory results were obtained and compared with experimental data obtained in the GSI experiments. As another important result, we highlight some directions for the development of a qualitatively superior version of the CRISP code with the implementation of more realistic and suitable physical models to be applied in stable and exotic nuclei that participate in the process. This new version of the code includes several substantial changes in the decay of the hot compound nucleus which allow satisfactory agreement with the experimental data and a reduction of the adjustment parameters.

  9. The Spallation Neutron Source accelerator system design

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, S., E-mail: stuarth@fnal.gov [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Abraham, W. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Aleksandrov, A. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Allen, C. [Techsource, Inc., 1475 Central Avenue, Suite 250, Los Alamos, NM 87544-3291 (United States); Alonso, J. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Anderson, D. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Arenius, D. [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Avenue, Newport News, VA 23606 (United States); Arthur, T. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Assadi, S. [Techsource, Inc., 1475 Central Avenue, Suite 250, Los Alamos, NM 87544-3291 (United States); Ayers, J.; Bach, P. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Badea, V. [Brookhaven National Laboratory, P.O. Box 5000, Upton, NY 11973-5000 (United States); Battle, R. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Beebe-Wang, J. [Brookhaven National Laboratory, P.O. Box 5000, Upton, NY 11973-5000 (United States); Bergmann, B.; Bernardin, J.; Bhatia, T.; Billen, J.; Birke, T.; Bjorklund, E. [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 (United States); and others

    2014-11-01

    The Spallation Neutron Source (SNS) was designed and constructed by a collaboration of six U.S. Department of Energy national laboratories. The SNS accelerator system consists of a 1 GeV linear accelerator and an accumulator ring providing 1.4 MW of proton beam power in microsecond-long beam pulses to a liquid mercury target for neutron production. The accelerator complex consists of a front-end negative hydrogen-ion injector system, an 87 MeV drift tube linear accelerator, a 186 MeV side-coupled linear accelerator, a 1 GeV superconducting linear accelerator, a 248-m circumference accumulator ring and associated beam transport lines. The accelerator complex is supported by ∼100 high-power RF power systems, a 2 K cryogenic plant, ∼400 DC and pulsed power supply systems, ∼400 beam diagnostic devices and a distributed control system handling ∼100,000 I/O signals. The beam dynamics design of the SNS accelerator is presented, as is the engineering design of the major accelerator subsystems.

  10. Cryogenic System for the Spallation Neutron Source

    Science.gov (United States)

    Arenius, D.; Chronis, W.; Creel, J.; Dixon, K.; Ganni, V.; Knudsen, P.

    2004-06-01

    The Spallation Neutron Source (SNS) is a neutron-scattering facility being built at Oak Ridge, TN for the US Department of Energy. The SNS accelerator linac consists of superconducting radio-frequency (SRF) cavities in cryostats (cryomodules). The linac cryomodules are cooled to 2.1 K by a 2300 watt cryogenic refrigeration system. As an SNS partner laboratory, Jefferson Lab is responsible for the installed integrated cryogenic system design for the SNS linac accelerator consisting of major subsystem equipment engineered and procured from industry. Jefferson Lab's work included developing the major vendor subsystem equipment procurement specifications, equipment procurement, and the integrated system engineering support of the field installation and commissioning. The major cryogenic system components include liquid nitrogen storage, gaseous helium storage, cryogen distribution transfer line system, 2.1-K cold box consisting of four stages of cold compressors, 4.5-K cold box, warm helium compressors with its associated oil removal, gas management, helium purification, gas impurity monitoring systems, and the supportive utilities of electrical power, cooling water and instrument air. The system overview, project organization, the important aspects, and the capabilities of the cryogenic system are described.

  11. Synchrotron based spallation neutron source concepts

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Y.

    1998-07-01

    During the past 20 years, rapid-cycling synchrotrons (RCS) have been used very productively to generate short-pulse thermal neutron beams for neutron scattering research by materials science communities in Japan (KENS), the UK (ISIS) and the US (IPNS). The most powerful source in existence, ISIS in the UK, delivers a 160-kW proton beam to a neutron-generating target. Several recently proposed facilities require proton beams in the MW range to produce intense short-pulse neutron beams. In some proposals, a linear accelerator provides the beam power and an accumulator ring compresses the pulse length to the required {approx} 1 {micro}s. In others, RCS technology provides the bulk of the beam power and compresses the pulse length. Some synchrotron-based proposals achieve the desired beam power by combining two or more synchrotrons of the same energy, and others propose a combination of lower and higher energy synchrotrons. This paper presents the rationale for using RCS technology, and a discussion of the advantages and disadvantages of synchrotron-based spallation sources.

  12. The Spallation Neutron Source accelerator system design

    Science.gov (United States)

    Henderson, S.; Abraham, W.; Aleksandrov, A.; Allen, C.; Alonso, J.; Anderson, D.; Arenius, D.; Arthur, T.; Assadi, S.; Ayers, J.; Bach, P.; Badea, V.; Battle, R.; Beebe-Wang, J.; Bergmann, B.; Bernardin, J.; Bhatia, T.; Billen, J.; Birke, T.; Bjorklund, E.; Blaskiewicz, M.; Blind, B.; Blokland, W.; Bookwalter, V.; Borovina, D.; Bowling, S.; Bradley, J.; Brantley, C.; Brennan, J.; Brodowski, J.; Brown, S.; Brown, R.; Bruce, D.; Bultman, N.; Cameron, P.; Campisi, I.; Casagrande, F.; Catalan-Lasheras, N.; Champion, M.; Champion, M.; Chen, Z.; Cheng, D.; Cho, Y.; Christensen, K.; Chu, C.; Cleaves, J.; Connolly, R.; Cote, T.; Cousineau, S.; Crandall, K.; Creel, J.; Crofford, M.; Cull, P.; Cutler, R.; Dabney, R.; Dalesio, L.; Daly, E.; Damm, R.; Danilov, V.; Davino, D.; Davis, K.; Dawson, C.; Day, L.; Deibele, C.; Delayen, J.; DeLong, J.; Demello, A.; DeVan, W.; Digennaro, R.; Dixon, K.; Dodson, G.; Doleans, M.; Doolittle, L.; Doss, J.; Drury, M.; Elliot, T.; Ellis, S.; Error, J.; Fazekas, J.; Fedotov, A.; Feng, P.; Fischer, J.; Fox, W.; Fuja, R.; Funk, W.; Galambos, J.; Ganni, V.; Garnett, R.; Geng, X.; Gentzlinger, R.; Giannella, M.; Gibson, P.; Gillis, R.; Gioia, J.; Gordon, J.; Gough, R.; Greer, J.; Gregory, W.; Gribble, R.; Grice, W.; Gurd, D.; Gurd, P.; Guthrie, A.; Hahn, H.; Hardek, T.; Hardekopf, R.; Harrison, J.; Hatfield, D.; He, P.; Hechler, M.; Heistermann, F.; Helus, S.; Hiatt, T.; Hicks, S.; Hill, J.; Hill, J.; Hoff, L.; Hoff, M.; Hogan, J.; Holding, M.; Holik, P.; Holmes, J.; Holtkamp, N.; Hovater, C.; Howell, M.; Hseuh, H.; Huhn, A.; Hunter, T.; Ilg, T.; Jackson, J.; Jain, A.; Jason, A.; Jeon, D.; Johnson, G.; Jones, A.; Joseph, S.; Justice, A.; Kang, Y.; Kasemir, K.; Keller, R.; Kersevan, R.; Kerstiens, D.; Kesselman, M.; Kim, S.; Kneisel, P.; Kravchuk, L.; Kuneli, T.; Kurennoy, S.; Kustom, R.; Kwon, S.; Ladd, P.; Lambiase, R.; Lee, Y. Y.; Leitner, M.; Leung, K.-N.; Lewis, S.; Liaw, C.; Lionberger, C.; Lo, C. C.; Long, C.; Ludewig, H.; Ludvig, J.; Luft, P.; Lynch, M.; Ma, H.; MacGill, R.; Macha, K.; Madre, B.; Mahler, G.; Mahoney, K.; Maines, J.; Mammosser, J.; Mann, T.; Marneris, I.; Marroquin, P.; Martineau, R.; Matsumoto, K.; McCarthy, M.; McChesney, C.; McGahern, W.; McGehee, P.; Meng, W.; Merz, B.; Meyer, R.; Meyer, R.; Miller, B.; Mitchell, R.; Mize, J.; Monroy, M.; Munro, J.; Murdoch, G.; Musson, J.; Nath, S.; Nelson, R.; Nelson, R.; O`Hara, J.; Olsen, D.; Oren, W.; Oshatz, D.; Owens, T.; Pai, C.; Papaphilippou, I.; Patterson, N.; Patterson, J.; Pearson, C.; Pelaia, T.; Pieck, M.; Piller, C.; Plawski, T.; Plum, M.; Pogge, J.; Power, J.; Powers, T.; Preble, J.; Prokop, M.; Pruyn, J.; Purcell, D.; Rank, J.; Raparia, D.; Ratti, A.; Reass, W.; Reece, K.; Rees, D.; Regan, A.; Regis, M.; Reijonen, J.; Rej, D.; Richards, D.; Richied, D.; Rode, C.; Rodriguez, W.; Rodriguez, M.; Rohlev, A.; Rose, C.; Roseberry, T.; Rowton, L.; Roybal, W.; Rust, K.; Salazer, G.; Sandberg, J.; Saunders, J.; Schenkel, T.; Schneider, W.; Schrage, D.; Schubert, J.; Severino, F.; Shafer, R.; Shea, T.; Shishlo, A.; Shoaee, H.; Sibley, C.; Sims, J.; Smee, S.; Smith, J.; Smith, K.; Spitz, R.; Staples, J.; Stein, P.; Stettler, M.; Stirbet, M.; Stockli, M.; Stone, W.; Stout, D.; Stovall, J.; Strelo, W.; Strong, H.; Sundelin, R.; Syversrud, D.; Szajbler, M.; Takeda, H.; Tallerico, P.; Tang, J.; Tanke, E.; Tepikian, S.; Thomae, R.; Thompson, D.; Thomson, D.; Thuot, M.; Treml, C.; Tsoupas, N.; Tuozzolo, J.; Tuzel, W.; Vassioutchenko, A.; Virostek, S.; Wallig, J.; Wanderer, P.; Wang, Y.; Wang, J. G.; Wangler, T.; Warren, D.; Wei, J.; Weiss, D.; Welton, R.; Weng, J.; Weng, W.-T.; Wezensky, M.; White, M.; Whitlatch, T.; Williams, D.; Williams, E.; Wilson, K.; Wiseman, M.; Wood, R.; Wright, P.; Wu, A.; Ybarrolaza, N.; Young, K.; Young, L.; Yourd, R.; Zachoszcz, A.; Zaltsman, A.; Zhang, S.; Zhang, W.; Zhang, Y.; Zhukov, A.

    2014-11-01

    The Spallation Neutron Source (SNS) was designed and constructed by a collaboration of six U.S. Department of Energy national laboratories. The SNS accelerator system consists of a 1 GeV linear accelerator and an accumulator ring providing 1.4 MW of proton beam power in microsecond-long beam pulses to a liquid mercury target for neutron production. The accelerator complex consists of a front-end negative hydrogen-ion injector system, an 87 MeV drift tube linear accelerator, a 186 MeV side-coupled linear accelerator, a 1 GeV superconducting linear accelerator, a 248-m circumference accumulator ring and associated beam transport lines. The accelerator complex is supported by ~100 high-power RF power systems, a 2 K cryogenic plant, ~400 DC and pulsed power supply systems, ~400 beam diagnostic devices and a distributed control system handling ~100,000 I/O signals. The beam dynamics design of the SNS accelerator is presented, as is the engineering design of the major accelerator subsystems.

  13. The spallation neutron source: New opportunities

    Indian Academy of Sciences (India)

    Ian S Anderson

    2008-11-01

    The spallation neutron source (SNS) facility became operational in the spring of 2006, and is now well on its way to become the world-leading facility for neutron scattering. Furthermore, the SNS and the HFIR reactor facility, newly outfitted with a brilliant cold source and guide hall, were brought together within a single Neutron Sciences Directorate at ORNL providing the opportunity to develop science and instrumentation programs which take advantage of the unique characteristics of each source. SNS and HFIR will both operate as scientific user facilities. Access to these facilities is being managed under an integrated proposal system, which also includes the Center for Nanophase Materials Sciences (CNMS) and the electron microscopes in the Shared Research Equipment (SHARE) program. Presently, SNS has three instruments operating in the user program and seven more will begin operations in 2008. When complete, the facility will accommodate 25 instruments enabling researchers from the United States and abroad to study materials science that forms the basis for new technologies in telecommunications, manufacturing, transportation, information technology, biotechnology, and health.

  14. Development of nuclear design criteria for neutron spallation sources

    Energy Technology Data Exchange (ETDEWEB)

    Sordo, F.; Abanades, A. [E.T.S. Industriales, Madrid Polytechnic University, UPM, J.Gutierrez Abascal, 2 -28006 Madrid (Spain)

    2008-07-01

    Spallation neutron sources allow obtaining high neutronic flux for many scientific and industrial applications. In recent years, several proposals have been made about its use, notably the European Spallation Source (ESS), the Japanese Spallation Source (JSNS) and the projects of Accelerator-Driven Subcritical reactors (ADS), particularly in the framework of EURATOM programs. Given their interest, it seems necessary to establish adequate design basis for guiding the engineering analysis and construction projects of this kind of installations. In this sense, all works done so far seek to obtain particular solutions to a particular design, but there has not been any general development to set up an engineering methodology in this field. In the integral design of a spallation source, all relevant physical processes that may influence its behaviour must be taken into account. Neutronic aspects (emitted neutrons and their spectrum, generation performance..), thermomechanical (energy deposition, cooling conditions, stress distribution..), radiological (spallation waste activity, activation reactions and residual heat) and material properties alteration due to irradiation (atomic displacements and gas generation) must all be considered. After analysing in a systematic manner the different options available in scientific literature, the main objective of this thesis was established as making a significant contribution to determine the limiting factors of the main aspects of spallation sources, its application range and the criteria for choosing optimal materials. To achieve this goal, a series of general simulations have been completed, covering all the relevant physical processes in the neutronic and thermal-mechanical field. Finally, the obtained criteria have been applied to the particular case of the design of the spallation source of subcritical reactors PDX-ADS and XT-ADS. These two designs, developed under the European R and D Framework Program, represent nowadays

  15. Alumina-magnesia Refractory Castables

    Institute of Scientific and Technical Information of China (English)

    Wang Jing

    2010-01-01

    @@ 1 Scope This standard specifies the classification,technical requirements,test methods,quality appraisal procedures,packing,marking,transportation,storage,and quality certificate of alumina-magnesia refractory castables.

  16. Tagging Spallation Backgrounds with Showers in Water-Cherenkov Detectors

    CERN Document Server

    Li, Shirley Weishi

    2015-01-01

    Cosmic-ray muons and especially their secondaries break apart nuclei ("spallation") and produce fast neutrons and beta-decay isotopes, which are backgrounds for low-energy experiments. In Super-Kamiokande, these beta decays are the dominant background in 6--18 MeV, relevant for solar neutrinos and the diffuse supernova neutrino background. In a previous paper, we showed that these spallation isotopes are produced primarily in showers, instead of in isolation. This explains an empirical spatial correlation between a peak in the muon Cherenkov light profile and the spallation decay, which Super-Kamiokande used to develop a new spallation cut. However, the muon light profiles that Super-Kamiokande measured are grossly inconsistent with shower physics. We show how to resolve this discrepancy and how to reconstruct accurate profiles of muons and their showers from their Cherenkov light. We propose a new spallation cut based on these improved profiles and quantify its effects. Our results can significantly benefit ...

  17. Spallative ablation of dielectrics by X-ray laser

    CERN Document Server

    Inogamov, N A; Faenov, A Ya; Khokhlov, V A; Shepelev, V V; Skobelev, I Yu; Kato, Y; Tanaka, M; Pikuz, T A; Kishimoto, M; Ishino, M; Nishikino, M; Fukuda, Y; Bulanov, S V; Kawachi, T; Petrov, Yu V; Anisimov, S I; Fortov, V E

    2009-01-01

    Short laser pulse in wide range of wavelengths, from infrared to X-ray, disturbs electron-ion equilibrium and rises pressure in a heated layer. The case where pulse duration $\\tau_L$ is shorter than acoustic relaxation time $t_s$ is considered in the paper. It is shown that this short pulse may cause thermomechanical phenomena such as spallative ablation regardless to wavelength. While the physics of electron-ion relaxation on wavelength and various electron spectra of substances: there are spectra with an energy gap in semiconductors and dielectrics opposed to gapless continuous spectra in metals. The paper describes entire sequence of thermomechanical processes from expansion, nucleation, foaming, and nanostructuring to spallation with particular attention to spallation by X-ray pulse.

  18. On the role of secondary pions in spallation targets

    CERN Document Server

    Mancusi, Davide; Colonna, Nicola; Boudard, Alain; Cortés-Giraldo, Miguel Antonio; Cugnon, Joseph; David, Jean-Christophe; Leray, Sylvie; Lerendegui-Marco, Jorge; Massimi, Cristian; Vlachoudis, Vasilis

    2016-01-01

    We use particle-transport simulations to show that secondary pions play a crucial role for the development of the hadronic cascade and therefore for the production of neutrons and photons from thick spallation targets. In particular, for the n_TOF lead spallation target, irradiated with 20-GeV/c protons, neutral pions are involved in the production of ~90% of the high-energy photons; charged pions participate in ~40% of the integral neutron yield. Nevertheless, photon and neutron yields are shown to be relatively insensitive to large changes of the average pion multiplicity in the individual spallation reactions. We characterize this robustness as a peculiar property of hadronic cascades in thick targets.

  19. Characterization of the radiation background at the Spallation Neutron Source

    Science.gov (United States)

    DiJulio, Douglas D.; Cherkashyna, Nataliia; Scherzinger, Julius; Khaplanov, Anton; Pfeiffer, Dorothea; Cooper-Jensen, Carsten P.; Fissum, Kevin G.; Kanaki, Kalliopi; Kirstein, Oliver; Ehlers, Georg; Gallmeier, Franz X.; Hornbach, Donald E.; Iverson, Erik B.; Newby, Robert J.; Hall-Wilton, Richard J.; Bentley, Phillip M.

    2016-09-01

    We present a survey of the radiation background at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory, TN, USA during routine daily operation. A broad range of detectors was used to characterize primarily the neutron and photon fields throughout the facility. These include a WENDI-2 extended range dosimeter, a thermoscientific NRD, an Arktis 4He detector, and a standard NaI photon detector. The information gathered from the detectors was used to map out the neutron dose rates throughout the facility and also the neutron dose rate and flux profiles of several different beamlines. The survey provides detailed information useful for developing future shielding concepts at spallation neutron sources, such as the European Spallation Source (ESS), currently under construction in Lund, Sweden.

  20. Neutron scattering instrumentation for biology at spallation neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Pynn, R. [Los Alamos National Laboratory, NM (United States)

    1994-12-31

    Conventional wisdom holds that since biological entities are large, they must be studied with cold neutrons, a domain in which reactor sources of neutrons are often supposed to be pre-eminent. In fact, the current generation of pulsed spallation neutron sources, such as LANSCE at Los Alamos and ISIS in the United Kingdom, has demonstrated a capability for small angle scattering (SANS) - a typical cold- neutron application - that was not anticipated five years ago. Although no one has yet built a Laue diffractometer at a pulsed spallation source, calculations show that such an instrument would provide an exceptional capability for protein crystallography at one of the existing high-power spoliation sources. Even more exciting is the prospect of installing such spectrometers either at a next-generation, short-pulse spallation source or at a long-pulse spallation source. A recent Los Alamos study has shown that a one-megawatt, short-pulse source, which is an order of magnitude more powerful than LANSCE, could be built with today`s technology. In Europe, a preconceptual design study for a five-megawatt source is under way. Although such short-pulse sources are likely to be the wave of the future, they may not be necessary for some applications - such as Laue diffraction - which can be performed very well at a long-pulse spoliation source. Recently, it has been argued by Mezei that a facility that combines a short-pulse spallation source similar to LANSCE, with a one-megawatt, long-pulse spallation source would provide a cost-effective solution to the global shortage of neutrons for research. The basis for this assertion as well as the performance of some existing neutron spectrometers at short-pulse sources will be examined in this presentation.

  1. Status of the AGS experiment for mercury spallation target development

    Energy Technology Data Exchange (ETDEWEB)

    Ikeda, Yujiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2000-03-01

    An experimental endeavor for exploitation of a MW class spallation target has been conducted using the AGS accelerator at BN on the neutron production along with the shock wave characteristics in the target, which are induced by a high intensity proton incident. This paper reviews the experiments, which has been carried out since 1997 in an international collaborative framework, namely the ASTE (AGS Spallation Target Experiment) collaboration with an emphasis on neutronics measurement, and gives the current status of the results provided through the experiment. (author)

  2. Neutron scattering instruments for the Spallation Neutron Source (SNS)

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, R.K.; Fornek, T. [Argonne National Lab., IL (United States); Herwig, K.W. [Oak Ridge National Lab., TN (United States)

    1998-07-01

    The Spallation Neutron Source (SNS) is a 1 MW pulsed spallation source for neutron scattering planned for construction at Oak Ridge National Laboratory. This facility is being designed as a 5-laboratory collaboration project. This paper addresses the proposed facility layout, the process for selection and construction of neutron scattering instruments at the SNS, the initial planning done on the basis of a reference set of ten instruments, and the plans for research and development (R and D) to support construction of the first ten instruments and to establish the infrastructure to support later development and construction of additional instruments.

  3. Gelcasting polycrystalline alumina

    Energy Technology Data Exchange (ETDEWEB)

    Janney, M.A. [Oak Ridge National Lab., TN (United States)

    1997-04-01

    This work is being done as part of a CRADA with Osram-Sylvania, Inc. (OSI) OSI is a major U.S. manufacturer of high-intensity lighting. Among its products is the Lumalux{reg_sign} line of high-pressure sodium vapor arc lamps, which are used for industrial, highway, and street lighting. The key to the performance of these lamps is the polycrystalline alumina (PCA) tube that is used to contain the plasma that is formed in the electric arc. That plasma consists of ionized sodium, mercury, and xenon vapors. The key attributes of the PCA tubes are their transparency (95% total transmittance in the visible region), their refractoriness (inner wall temperature can reach 1400{degrees}C), and their chemical resistance (sodium and mercury vapor are extremely corrosive). The current efficiency of the lamps is very high, on the order of several hundred lumens / watt. (Compare - incandescent lamps -13 lumens/watt fluorescent lamps -30 lumens/watt.) Osram-Sylvania would like to explore using gelcasting to form PCA tubes for Lumalux{reg_sign} lamps, and eventually for metal halide lamps (known as quartz-halogen lamps). Osram-Sylvania, Inc. currently manufactures PCA tubes by isostatic pressing. This process works well for the shapes that they presently use. However, there are several types of tubes that are either difficult or impossible to make by isostatic pressing. It is the desire to make these new shapes and sizes of tubes that has prompted Osram-Sylvania`s interest in gelcasting. The purpose of the CRADA is to determine the feasibility of making PCA items having sufficient optical quality that they are useful in lighting applications using gelcasting.

  4. Development of Cast Alumina-Forming Austenitic Stainless Steels

    Science.gov (United States)

    Muralidharan, G.; Yamamoto, Y.; Brady, M. P.; Walker, L. R.; Meyer, H. M., III; Leonard, D. N.

    2016-09-01

    Cast Fe-Ni-Cr chromia-forming austenitic stainless steels with Ni levels up to 45 wt.% are used at high temperatures in a wide range of industrial applications that demand microstructural stability, corrosion resistance, and creep strength. Although alumina scales offer better corrosion protection at these temperatures, designing cast austenitic alloys that form a stable alumina scale and achieve creep strength comparable to existing cast chromia-forming alloys is challenging. This work outlines the development of cast Fe-Ni-Cr-Al austenitic stainless steels containing about 25 wt.% Ni with good creep strength and the ability to form a protective alumina scale for use at temperatures up to 800-850°C in H2O-, S-, and C-containing environments. Creep properties of the best alloy were comparable to that of HK-type cast chromia-forming alloys along with improved oxidation resistance typical of alumina-forming alloys. Challenges in the design of cast alloys and a potential path to increasing the temperature capability are discussed.

  5. Development of Cast Alumina-Forming Austenitic Stainless Steels

    Science.gov (United States)

    Muralidharan, G.; Yamamoto, Y.; Brady, M. P.; Walker, L. R.; Meyer, H. M., III; Leonard, D. N.

    2016-11-01

    Cast Fe-Ni-Cr chromia-forming austenitic stainless steels with Ni levels up to 45 wt.% are used at high temperatures in a wide range of industrial applications that demand microstructural stability, corrosion resistance, and creep strength. Although alumina scales offer better corrosion protection at these temperatures, designing cast austenitic alloys that form a stable alumina scale and achieve creep strength comparable to existing cast chromia-forming alloys is challenging. This work outlines the development of cast Fe-Ni-Cr-Al austenitic stainless steels containing about 25 wt.% Ni with good creep strength and the ability to form a protective alumina scale for use at temperatures up to 800-850°C in H2O-, S-, and C-containing environments. Creep properties of the best alloy were comparable to that of HK-type cast chromia-forming alloys along with improved oxidation resistance typical of alumina-forming alloys. Challenges in the design of cast alloys and a potential path to increasing the temperature capability are discussed.

  6. Fission, spallation or fusion-based neutron sources

    Indian Academy of Sciences (India)

    Kurt N Clausen

    2008-10-01

    In this paper the most promising technology for high power neutron sources is briefly discussed. The conclusion is that the route to high power neutron sources in the foreseeable future is spallation – short or long pulse or even CW – all of these sources will have areas in which they excel.

  7. Spallation reactions. A successful interplay between modeling and applications

    CERN Document Server

    David, J -C

    2015-01-01

    The spallation reactions are a type of nuclear reaction which occur in space by interaction of the cosmic rays with interstellar bodies. The first spallation reactions induced with an accelerator took place in 1947 at the Berkeley cyclotron (University of California) with 200 MeV deuterons and 400 MeV alpha beams. They highlighted the multiple emission of neutrons and charged particles and the production of a large number of residual nuclei far different from the target nuclei. The same year R. Serber describes the reaction in two steps: a first and fast one with high-energy particle emission leading to an excited remnant nucleus, and a second one, much slower, the de-excitation of the remnant. In 2010 IAEA organized a worskhop to present the results of the most widely used spallation codes within a benchmark of spallation models. If one of the goals was to understand the deficiencies, if any, in each code, one remarkable outcome points out the overall high-quality level of some models and so the great improv...

  8. Study on induced radioactivity of China Spallation Neutron Source

    Institute of Scientific and Technical Information of China (English)

    吴青彪; 王庆斌; 吴靖民; 马忠剑

    2011-01-01

    China Spallation Neutron Source (CSNS) is the first High Energy Intense Proton Accelerator planned to be constructed in China during the State Eleventh Five-Year Plan period, whose induced radioactivity is very important for occupational disease hazard as

  9. Transuranics Transmutation Using Neutrons Spectrum from Spallation Reactions

    Directory of Open Access Journals (Sweden)

    Maurício Gilberti

    2015-01-01

    Full Text Available The aim is to analyse the neutron spectrum influence in a hybrid system ADS-fission inducing transuranics (TRUs transmutation. A simple model consisting of an Accelerator-Driven Subcritical (ADS system containing spallation target, moderator or coolant, and spheres of actinides, “fuel,” at different locations in the system was modelled. The simulation was performed using the MCNPX 2.6.0 particles transport code evaluating capture (n,γ and fission (n,f reactions, as well as the burnup of actinides. The goal is to examine the behaviour and influences of the hard neutron spectrum from spallation reactions in the transmutation, without the contribution or interference of multiplier subcritical medium, and compare the results with those obtained from the neutron fission spectrum. The results show that the transmutation efficiency is independent of the spallation target material used, and the neutrons spectrum from spallation does not contribute to increased rates of actinides transmutation even in the vicinity of the target.

  10. HYSPEC : A CRYSTAL TIME OF FLIGHT HYBRID SPECTROMETER FOR THE SPALLATION NEUTRON SOURCE.

    Energy Technology Data Exchange (ETDEWEB)

    SHAPIRO,S.M.; ZALIZNYAK,I.A.

    2002-12-30

    This document lays out a proposal by the Instrument Development Team (IDT) composed of scientists from leading Universities and National Laboratories to design and build a conceptually new high-flux inelastic neutron spectrometer at the pulsed Spallation Neutron Source (SNS) at Oak Ridge. This instrument is intended to supply users of the SNS and scientific community, of which the IDT is an integral part, with a platform for ground-breaking investigations of the low-energy atomic-scale dynamical properties of crystalline solids. It is also planned that the proposed instrument will be equipped with a polarization analysis capability, therefore becoming the first polarized beam inelastic spectrometer in the SNS instrument suite, and the first successful polarized beam inelastic instrument at a pulsed spallation source worldwide. The proposed instrument is designed primarily for inelastic and elastic neutron spectroscopy of single crystals. In fact, the most informative neutron scattering studies of the dynamical properties of solids nearly always require single crystal samples, and they are almost invariably flux-limited. In addition, in measurements with polarization analysis the available flux is reduced through selection of the particular neutron polarization, which puts even more stringent limits on the feasibility of a particular experiment. To date, these investigations have mostly been carried out on crystal spectrometers at high-flux reactors, which usually employ focusing Bragg optics to concentrate the neutron beam on a typically small sample. Construction at Oak Ridge of the high-luminosity spallation neutron source, which will provide intense pulsed neutron beams with time-averaged fluxes equal to those at medium-flux reactors, opens entirely new opportunities for single crystal neutron spectroscopy. Drawing upon experience acquired during decades of studies with both crystal and time-of-flight (TOF) spectrometers, the IDT has developed a conceptual

  11. Transport properties of alumina nanofluids

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Kau-Fui Vincent; Kurma, Tarun [Department of Mechanical and Aerospace Engineering, University of Miami, Coral Gables, FL 33124 (United States)], E-mail: kwong@miami.edu

    2008-08-27

    Recent studies have showed that nanofluids have significantly greater thermal conductivity compared to their base fluids. Large surface area to volume ratio and certain effects of Brownian motion of nanoparticles are believed to be the main factors for the significant increase in the thermal conductivity of nanofluids. In this paper all three transport properties, namely thermal conductivity, electrical conductivity and viscosity, were studied for alumina nanofluid (aluminum oxide nanoparticles in water). Experiments were performed both as a function of volumetric concentration (3-8%) and temperature (2-50 deg. C). Alumina nanoparticles with a mean diameter of 36 nm were dispersed in water. The effect of particle size was not studied. The transient hot wire method as described by Nagaska and Nagashima for electrically conducting fluids was used to test the thermal conductivity. In this work, an insulated platinum wire of 0.003 inch diameter was used. Initial calibration was performed using de-ionized water and the resulting data was within 2.5% of standard thermal conductivity values for water. The thermal conductivity of alumina nanofluid increased with both increase in temperature and concentration. A maximum thermal conductivity of 0.7351 W m{sup -1} K{sup -1} was recorded for an 8.47% volume concentration of alumina nanoparticles at 46.6 deg. C. The effective thermal conductivity at this concentration and temperature was observed to be 1.1501, which translates to an increase in thermal conductivity by 22% when compared to water at room temperature. Alumina being a good conductor of electricity, alumina nanofluid displays an increasing trend in electrical conductivity as volumetric concentration increases. A microprocessor-based conductivity/TDS meter was used to perform the electrical conductivity experiments. After carefully calibrating the conductivity meter's glass probe with platinum tip, using a standard potassium chloride solution, readings were

  12. Transport properties of alumina nanofluids.

    Science.gov (United States)

    Wong, Kau-Fui Vincent; Kurma, Tarun

    2008-08-27

    Recent studies have showed that nanofluids have significantly greater thermal conductivity compared to their base fluids. Large surface area to volume ratio and certain effects of Brownian motion of nanoparticles are believed to be the main factors for the significant increase in the thermal conductivity of nanofluids. In this paper all three transport properties, namely thermal conductivity, electrical conductivity and viscosity, were studied for alumina nanofluid (aluminum oxide nanoparticles in water). Experiments were performed both as a function of volumetric concentration (3-8%) and temperature (2-50 °C). Alumina nanoparticles with a mean diameter of 36 nm were dispersed in water. The effect of particle size was not studied. The transient hot wire method as described by Nagaska and Nagashima for electrically conducting fluids was used to test the thermal conductivity. In this work, an insulated platinum wire of 0.003 inch diameter was used. Initial calibration was performed using de-ionized water and the resulting data was within 2.5% of standard thermal conductivity values for water. The thermal conductivity of alumina nanofluid increased with both increase in temperature and concentration. A maximum thermal conductivity of 0.7351 W m(-1) K(-1) was recorded for an 8.47% volume concentration of alumina nanoparticles at 46.6 °C. The effective thermal conductivity at this concentration and temperature was observed to be 1.1501, which translates to an increase in thermal conductivity by 22% when compared to water at room temperature. Alumina being a good conductor of electricity, alumina nanofluid displays an increasing trend in electrical conductivity as volumetric concentration increases. A microprocessor-based conductivity/TDS meter was used to perform the electrical conductivity experiments. After carefully calibrating the conductivity meter's glass probe with platinum tip, using a standard potassium chloride solution, readings were taken at

  13. Thermal-Hydraulic Analysis of PDS-XADS Spallation Target%PDS-XADS散裂靶热工水力分析

    Institute of Scientific and Technical Information of China (English)

    艾尼塞; 俞冀阳; 杨永伟

    2013-01-01

    本文对小型加速器驱动的次临界系统(ADS)-PDS-XADS散裂靶进行了热工水力分析.分析的XADS型实验堆基于欧洲PDS-XADS实验项目的设计,使用铅铋合金(LBE)作为冷却剂.散裂靶是ADS的核心部件之一,用以确保反应堆功率维持在指定水平.本文利用计算流体力学软件ANSYSCFX 11.0对散裂靶的下部区域进行热工水力分析.分析采用稳态计算、剪切应力输运(SST)湍流模型,在壁面边界条件处采用自动壁面函数法,针对不同的散裂靶设计进行计算流体力学(CFD)分析,最后根据散裂靶设计限值选择最优设计方案.%The thermal-hydraulic analysis of PDS-XADS spallation target for 80 MW reactor core power was studied. PDS-XADS is a small scale experimental accelerator driven sub-critical system (ADS). The analysis presented in this paper was based on lead bismuth eutectic (LBE) cooled XADS type experimental reactors, which are the designs of the European experimental PDS-XADS project. The spallation target is a very important component of ADS because it is responsible to keep the reactor power at the required level by spallation reactions. A high rate of neutron production by spallation reaction creates the problem of decay heat cooling. LBE flow is properly cooled, but the window is not properly cooled because of the stagnation point in the pole of the window. It would be very difficult to keep the window temperature below the design limit, which is an important design limit challenge. Thermal-hydraulic analysis of LBE spallation target was carried out by using ANSYS CFX 11.0. The detailed CFD analysis, which reveals thermal and hydraulic conditions in the window and spallation region, was carried out for different spallation target designs. Finally, the spallation target design limit was used to choose the best design.

  14. Alumina Coating on Carbon Fibers by Sol-Gel Method

    OpenAIRE

    2006-01-01

    Alumina precursor film was coated on carbon fibers by a sol-gel method using aluminum alkoxide solution. The optimum coating condition for the concentration of alumina alkoxide and silane coupling agent was determined to uniformly coat alumina precursor on carbon fibers. Alumina precursor converted to alumina ceramics by heating at 750℃. SEM and EPMA showed that alumina ceramics was uniformly coated on carbon fibers. The thickness of alumina layer increased with increasing coating times. The ...

  15. High-Power Linac for the Spallation Neutron Source

    Science.gov (United States)

    Rej, D. J.

    2002-04-01

    The Spallation Neutron Source (SNS) will be the world’s most intense source of neutrons for fundamental science and industrial applications. Design and construction of this facility, located at Oak Ridge, is a joint venture between six DOE laboratories. Construction began in 1999 and is currently ahead of the scheduled 2006 completion date. Injecting a high-power, pulsed proton beam into a mercury target produces neutrons. In this talk, we review the physics requirements, design, and status of the construction of the 1-GeV, 1.4-MW average power RF linac for SNS. The accelerator consists of a drift tube linac (DTL), a coupled-cavity linac (CCL), and a superconducting rf (SRF) linac. The phase and quadrupole settings are set to avoid structure and parametric resonances, with coherent resonances posing minimal risk for emittance growth. The DTL is 37 m long and accelerates the ions to 87 MeV. The CCL is 55 m long and accelerates the ions to 186 MeV. The rf structure design and stability for both the DTL and CCL have been validated with scale models. The SRF linac has a modular design to accelerate ions to 1000 MeV, with a straightforward upgrade to 1.3 GeV at a later date. 3D particle-in-cell simulations of beam dynamics are performed to validate performance. The accelerator utilizes 93 MW of pulsed power operating continuously at 60-Hz with an 8factor. Approximately one hundred 402.5 or 805-MHz klystrons, with outputs between 0.55 and 5 MW, are used. The klystrons are powered by a novel converter-modulator that takes advantage of recent advances in IGBT switch plate assemblies and low-loss material cores for boost transformer. Beam diagnostics include position, phase, profile, and current monitors. They are designed to enable accurate beam steering and matching, and to minimize beam loss that would lead to activation and prevent hands-on maintenance.

  16. Processing and Performance of Alumina Fiber Reinforced Alumina Composites

    Institute of Scientific and Technical Information of China (English)

    P.Y.Lee; T.Uchijima; T.Yano

    2003-01-01

    Processing of alumina fiber-reinforced alumina matrix composites by hot-pressing was described. The mechanical properties of the composites fabricated by different sintering conditions including temperature and pressure have been investigated. The results indicated that the higher sintering temperature and pressure corresponded to the higher bulk density and higher maximum strength of the composite, whereas the pseudo-ductility of the composite was lower. The preliminary results of the composite with monazite-coated fibers showed that maximum strength could be improved up to 35% compared with the noncoated fiber composite in the same sintering condition. Moreover, the fracture behavior of the composite changed from completely brittle fracture to non-brittle fracture under the suitable sintering conditions. SEM observation of the fracture surface indicated that the coating worked as a protective barrier and avoided sintering of the fibers together even at high temperature and pressure during densification process.

  17. Overcoming High Energy Backgrounds at Pulsed Spallation Sources

    CERN Document Server

    Cherkashyna, Nataliia; DiJulio, Douglas D.; Khaplanov, Anton; Pfeiffer, Dorothea; Scherzinger, Julius; Cooper-Jensen, Carsten P.; Fissum, Kevin G.; Ansell, Stuart; Iverson, Erik B.; Ehlers, Georg; Gallmeier, Franz X.; Panzner, Tobias; Rantsiou, Emmanouela; Kanaki, Kalliopi; Filges, Uwe; Kittelmann, Thomas; Extegarai, Maddi; Santoro, Valentina; Kirstein, Oliver; Bentley, Phillip M.

    2015-01-01

    Instrument backgrounds at neutron scattering facilities directly affect the quality and the efficiency of the scientific measurements that users perform. Part of the background at pulsed spallation neutron sources is caused by, and time-correlated with, the emission of high energy particles when the proton beam strikes the spallation target. This prompt pulse ultimately produces a signal, which can be highly problematic for a subset of instruments and measurements due to the time-correlated properties, and different to that from reactor sources. Measurements of this background have been made at both SNS (ORNL, Oak Ridge, TN, USA) and SINQ (PSI, Villigen, Switzerland). The background levels were generally found to be low compared to natural background. However, very low intensities of high-energy particles have been found to be detrimental to instrument performance in some conditions. Given that instrument performance is typically characterised by S/N, improvements in backgrounds can both improve instrument pe...

  18. A non-equilibrium microscopic description of spallation

    CERN Document Server

    Napolitani, P

    2016-01-01

    We investigate the prompt emission of few intermediate-mass fragments in spallation reactions induced by protons and deuterons in the 1 GeV range. Such emission has a minor contribution to the total reaction cross section, but it may overcome evaporation and fission channels in the formation of light nuclides. The role of mean-field dynamics and phase-space fluctuations in these reactions is investigated through the Boltzmann-Langevin transport equation. We found that a process of frustrated fragmentation and re-aggregation is a prominent mechanism of production of IMFs which can not be assimilated to the statistical decay of a compound nucleus. Very interestingly, this process may yield a small number of IMF in the exit channel, which may even reduce to two, and be wrongly confused with ordinary asymmetric fission. This interpretation, inspired by nuclear-spallation experiments, can be generalised to heavy-ion collisions approaching the fragmentation threshold.

  19. Neutronic studies of the coupled moderators for spallation neutron sources

    Institute of Scientific and Technical Information of China (English)

    Yin Wen; Liang Jiu-Qing

    2005-01-01

    We investigate the neutronic performance of coupled moderators to be implemented in spallation neutron sources by Monte-Carlo simulation and give the slow neutron spectra for the cold and thermal moderators. CH4 moderator can provide slow neutrons with highly desirable characteristics and will be used in low-power spallation neutron soureces. The slow neutron intensity extracted from different angles has been calculated. The capability of moderation of liquid H2 is lower than H2O and liquid CH4 due to lower atomic number density of hydrogen but we can compensate for this disadvantage by using a premoderator. The H2O premoderator of 2cm thickness can reduce the heat deposition in the cold moderator by about 33% without spoiling the neutron pulse.

  20. An overview of an accelerator-based neutron spallation source

    Energy Technology Data Exchange (ETDEWEB)

    Lessner, E.S.

    1996-06-01

    An overview of the feasibility study of a 1-MW pulsed spallation source is presented. The machine delivers 1 MW of proton beam power to spallation targets where slow neutrons are produced. The slow neutrons can be used for isotope production, materials irradiation, and neutron scattering research. The neutron source facility is based on a rapid cycling synchrotron (RCS) and consists of a 400-MeV linac, a 30-Hz RCS that accelerates the 400-MeV beam to 2 GeV, and two neutron-generating target stations. The RCS accelerates an average proton beam current of 0.5 mA, corresponding to 1.04 x 10{sup 14} protons per pulse. This intensity is about two times higher than that of existing machines. A key feature of this accelerator system design is that beam losses are minimized from injection to extraction, reducing activation to levels consistent with hands-on maintenance.

  1. Spallation neutron source and other high intensity froton sources

    Energy Technology Data Exchange (ETDEWEB)

    Weiren Chou

    2003-02-06

    This lecture is an introduction to the design of a spallation neutron source and other high intensity proton sources. It discusses two different approaches: linac-based and synchrotron-based. The requirements and design concepts of each approach are presented. The advantages and disadvantages are compared. A brief review of existing machines and those under construction and proposed is also given. An R&D program is included in an appendix.

  2. Spallation and fracture resulting from reflected and intersecting stress waves.

    Science.gov (United States)

    Kinslow, R.

    1973-01-01

    Discussion of the effects of stress waves produced in solid by explosions or high-velocity impacts. These waves rebound from free surfaces in the form of tensile waves that are capable of causing internal fractures or spallation of the material. The high-speed framing camera is shown to be an important tool for observing the stress waves and fracture in transparent targets, and its photographs provide valuable information on the mechanics of fracture.

  3. Monte Carlo simulation of NSE at reactor and spallation sources

    Energy Technology Data Exchange (ETDEWEB)

    Zsigmond, G.; Wechsler, D.; Mezei, F. [Hahn-Meitner-Institut Berlin, Berlin (Germany)

    2001-03-01

    A MC (Monte Carlo) computation study of NSE (Neutron Spin Echo) has been performed by means of VITESS investigating the classic and TOF-NSE options at spallation sources. The use of white beams in TOF-NSE makes the flipper efficiency in function of the neutron wavelength an important issue. The emphasis was put on exact evaluation of flipper efficiencies for wide wavelength-band instruments. (author)

  4. Irradiation facilities at the spallation neutron source SINQ

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, E.; Ledermann, J.; Aebersold, H.; Kuehne, G.; Kohlik, K. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    Four independent experiments for sample irradiation are under construction and in preparation for operational tests at the spallation source SINQ. Three of them are located inside a thermal beam port with end positions inside or near the moderator tank. The other experiment will be established at the end position of a super mirror lined neutron guide for applications with cold neutrons. (author) 3 figs., 1 tab., 6 refs.

  5. Sintering behaviour of spinel–alumina composites

    Indian Academy of Sciences (India)

    Soumen Pal; A K Bandyopadhyay; P G Pal; S Mukherjee; B N Samaddar

    2009-04-01

    Study of alumina–magnesia binary phase diagram reveals that around 40–50 wt% alumina dissolves in spinel (MgAl2O4) at 1600°C. Solid solubility of alumina in spinel decreases rapidly with decreasing temperature, which causes exsolution of alumina from spinel phase. Previous work of one of the authors revealed that the exsolution of alumina makes some interlocking structures in between alumina and spinel phases. In the present investigation, refractory grade calcined alumina and spinel powder were used to make different batch compositions. Green pellets, formed at a pressure of 1550 kg cm-2 were fired at different temperatures of 1500°, 1550° and 1600°C for 2 h soaking time. Bulk density, percent apparent porosity, firing shrinkage etc were measured at each temperature. Sintering results were analysed to understand the mechanism of spinel–alumina interactions. SEM study of present samples does not reveal the distinct precipitation of needle shaped -alumina from spinel, but has some effect on densification process of spinel–alumina composites. Microstructural differences between present and previous work suggest an ample scope of further work in spinel–alumina composites.

  6. Material issues relating to high power spallation neutron sources

    Science.gov (United States)

    Futakawa, M.

    2015-02-01

    Innovative researches using neutrons are being performed at the Materials and Life Science Experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC), in which a mercury target system is installed for MW-class pulse spallation neutron sources. In order to produce neutrons by the spallation reaction, proton beams are injected into the mercury target. At the moment, when the intense proton beam hits the target, pressure waves are generated in mercury because of the abrupt heat deposition. The pressure waves interact with the target vessel, leading to negative pressure that may cause cavitation along the vessel wall, i.e. on the interface between liquid and solid metals. On the other hand, the structural materials are subjected to irradiation damage due to protons and neutrons, very high cycle fatigue damages and so-called "liquid metal embrittlement". That is, the structural materials must be said to be exposed to the extremely severe environments. In the paper, research and development relating to the material issues in the high power spallation neutron sources that has been performed so far at J-PARC is summarized.

  7. Spallation Process of Thermally Grown Oxides by In-Situ CCD Monitoring Technique

    Institute of Scientific and Technical Information of China (English)

    QI Yu-hong; Philippe Lours; Yannick Le Maoult

    2009-01-01

    In cooling process of Fe-Cr-AI alloy oxidized at 1 300 ℃, the effect of cooling speed and exposure time on oxide spalled area fraction and successive variety of the spalled region were studied by investigating evolvement of the thermally grown oxide using in-situ CCD monitoring technique. The results showed that oxide spallation can be re-strained by controlling cooling speed and the critical temperature drop of spallation initiation which is closely related to the oxide thickness or exposure time, and the spallation process of a little region may be described in more detail as two routes:from the oxide/substrate interface micro-decohesion, micro-buckles, buckle spreading, buckle crack to spallation and from the interface micro-decohesion, micro-buckles, buckle crack and spallation to the residual oxide decohesion and spallation.

  8. Astrophysical Li-7 as a product of big bang nucleosynthesis and galactic cosmic-ray spallation

    Science.gov (United States)

    Olive, Keith A.; Schramm, David N.

    1992-01-01

    The astrophysical Li-7 abundance is considered to be largely primordial, while the Be and B abundances are thought to be due to galactic cosmic ray (GCR) spallation reactions on top of a much smaller big bang component. But GCR spallation should also produce Li-7. As a consistency check on the combination of big bang nucleosynthesis and GCR spallation, the Be and B data from a sample of hot population II stars is used to subtract from the measured Li-7 abundance an estimate of the amount generated by GCR spallation for each star in the sample, and then to add to this baseline an estimate of the metallicity-dependent augmentation of Li-7 due to spallation. The singly reduced primordial Li-7 abundance is still consistent with big bang nucleosynthesis, and a single GCR spallation model can fit the Be, B, and corrected Li-7 abundances for all the stars in the sample.

  9. Ion guiding in alumina capillaries

    DEFF Research Database (Denmark)

    Juhász, Z.; Sulik, B.; Biri, S.;

    2009-01-01

    Transmission of a few keV impact energy Ne ions through capillaries in anodic alumina membranes has been studied with different ion counting methods using an energy dispersive electrostatic spectrometer, a multichannel plate (MCP) array and sensitive current-measurement. In the present work, we...... focus our attention to the measurements with the MCP array. The alumina capillaries were prepared by electro-chemical oxidation of aluminium foils. For the present experiments guiding of 3-6 keV Ne ions has been studied in two samples with capillary diameter of about 140 nm and 260 nm and with capillary...... length of about 15 μm. At these energies, the ions have been efficiently guided by the capillaries up to few degrees tilt angle. In this work, we compare the results obtained by the energy dispersive spectrometer to those studied by the MCP array. © 2008 Elsevier B.V. All rights reserved....

  10. Wettability of Aluminum on Alumina

    Science.gov (United States)

    Bao, Sarina; Tang, Kai; Kvithyld, Anne; Tangstad, Merete; Engh, Thorvald Abel

    2011-12-01

    The wettability of molten aluminum on solid alumina substrate has been investigated by the sessile drop technique in a 10-8 bar vacuum or under argon atmosphere in the temperature range from 1273 K to 1673 K (1000 °C to 1400 °C). It is shown that the reduction of oxide skin on molten aluminum is slow under normal pressures even with ultralow oxygen potential, but it is enhanced in high vacuum. To describe the wetting behavior of the Al-Al2O3 system at lower temperatures, a semiempirical calculation was employed. The calculated contact angle at 973 K (700 °C) is approximately 97 deg, which indicates that aluminum does not wet alumina at aluminum casting temperatures. Thus, a priming height is required for aluminum to infiltrate a filter. Wetting in the Al-Al2O3 system increases with temperature.

  11. Study of particle transport in a high power spallation target for an accelerator driven transmutation system

    OpenAIRE

    Shetty, Nikhil Vittal

    2013-01-01

    Transmutation of highly radioactive nuclear waste can be performed using an accelerator driven system (ADS), where high energy protons impinge on a spallation target to produce neutrons. These neutrons are multiplied in a subcritical core, while simultaneously fissioning the minor actinides into short lived or stable nuclides. AGATE is a project envisaged to demonstrate the feasibility of transmutation in a gas (helium) cooled ADS using solid spallation target. Development of the spallation t...

  12. Energy dependence of isotopic spectra from spallation residues; Dependance en energie des spectres isotopiques de residus de spallation

    Energy Technology Data Exchange (ETDEWEB)

    Audouin, L

    2003-09-01

    Spallation reactions are collisions between heavy nuclei and light particle with an energy of a few hundreds MeV. The y are considered as a suitable way to create high- flux neutrons sources, which may used for example for the transmutation of nuclear wastes (hybrid reactors). The study of the residues from such reactions is both a way to understand the physics of the spallation and to provide information required for the design of industrial targets. The residues from the spallation of lead by proton at 500 MeV have been measured using the inverse kinematics technique in the FRS (fragments recoil separator). spectrometer from GSI (Barmstadt). This low energy required the use of new technique, for the experimental setup as well as during the analysis. The fragments were identified in-flight, prior to {beta} decay. Complete isotopic distributions are obtained with an accuracy ranging between 10 and 30%. Detailed information on the reaction kinematics are also obtained. Data are in excellent agreement with radio-chemical measurements, and bring new insights about the spallation process. The comparison with data measured on the same system with an incident energy of 1 GeV allows to discuss the influence of the projectile energy on the residues formation. It is concluded that the independence of the shape of the isobaric production cross sections regarding mass and energy of the projectile is preserved at low incident energies. The behaviour of Monte-Carlo codes is discussed with respect to those sets of data. The calculations show an improving agreement with decreasing energy, indicating that high-energy phenomena, for which some common assumptions become questionable, are the main reason for the observed discrepancies. (author)

  13. Integral measurements of neutron production in spallation targets; Mesure integrale de la production de neutrons dans des cibles de spallation

    Energy Technology Data Exchange (ETDEWEB)

    Frehaut, J.; Deneuville, D.; Ledoux, X.; Lochard, J.P.; Longuet, J.L.; Petibon, E.; Alrick, K.; Bownan, D.; Cverna, F.; King, N.S.P.; Morgan, G.L. [Los Alamos National Lab., NM (United States); Greene, G.; Hanson, A.; Snead, L. [Brookhaven National Lab., Upton, NY (United States); Thompson, R. [Bechtel Nevada Corp., Las Vegas, NV (United States); Ward, T

    1998-12-31

    Measurements of neutron production for thick iron, tungsten and lead targets of different diameter prototypic for spallation systems have been made at SATURNE in an incident proton energy range from 400 MeV to 2 GeV. TIERCE code system calculations are in good agreement with experiment for iron and large diameter tungsten and lead targets. They overestimate the measured neutron production for tungsten and lead targets for diameter {<=}20 cm. (author) 10 refs.

  14. Management of the radioactive waste of European Spallation Source within the Swedish waste disposal system

    Energy Technology Data Exchange (ETDEWEB)

    Ene, Daniela [European Spallation Source AB, ESS-AB (Sweden); Forsstroem, H. [Svensk Kaernbraenslehantering AB, SKB (Sweden)

    2014-07-01

    The European Spallation Source AB (ESS) is the European common effort in designing and building a next generation large-scale user facility for studies of the structure and dynamics of materials. The proposed schematic layout of the ESS facility is based on a linear driver (linac) directing the proton beam (5 MW of 2.5 GeV) of 2.8 ms long pulses with a 20 Hz on a tungsten target where neutrons are produced via spallation reactions. Further the neutrons will be moderated to thermal and sub-thermal energies in a couple of moderators placed around the target. The moderators feed 22 beam-lines guiding the neutrons to the scattering instruments, mainly for neutron scattering research, as has been previously mentioned. The ESS will generate specific types of radioactive waste. This waste should be handled and disposed of within the Swedish radioactive waste management system, which is owned and operated by Svensk Kaernbraenslehantering AB, (SKB). The main objectives of this work are: i) To estimate types and quantities of waste that the ESS project will generate at different stages: commission, operation, decommissioning; ii) To allocate the waste to specific disposal route; iii) To assess the disposal volumes needed and to ensure that the ESS waste may safely be accommodated within the Swedish disposal system, SKB The amounts of ESS waste and classifications were derived using: i) precise Monte Carlo calculations ii) scaling the activity from the operation experience of the existing spallation source installations for waste such it is difficult to predict level of activation or for components of the facility in stage of the pre-conceptual model. Associated waste treatment/conditioning options were further analyzed in order to define the waste type and packet descriptions in agreement with Swedish regulations and policy. The potential final disposal routes for high activated components were decided via the comparison of the activity levels of the isotopes inside the

  15. Structural Effects of Lanthanide Dopants on Alumina

    Science.gov (United States)

    Patel, Ketan; Blair, Victoria; Douglas, Justin; Dai, Qilin; Liu, Yaohua; Ren, Shenqiang; Brennan, Raymond

    2017-01-01

    Lanthanide (Ln3+) doping in alumina has shown great promise for stabilizing and promoting desirable phase formation to achieve optimized physical and chemical properties. However, doping alumina with Ln elements is generally accompanied by formation of new phases (i.e. LnAlO3, Ln2O3), and therefore inclusion of Ln-doping mechanisms for phase stabilization of the alumina lattice is indispensable. In this study, Ln-doping (400 ppm) of the alumina lattice crucially delays the onset of phase transformation and enables phase population control, which is achieved without the formation of new phases. The delay in phase transition (θ → α), and alteration of powder morphology, particle dimensions, and composition ratios between α- and θ-alumina phases are studied using a combination of solid state nuclear magnetic resonance, electron microscopy, digital scanning calorimetry, and high resolution X-ray diffraction with refinement fitting. Loading alumina with a sparse concentration of Ln-dopants suggests that the dopants reside in the vacant octahedral locations within the alumina lattice, where complete conversion into the thermodynamically stable α-domain is shown in dysprosium (Dy)- and lutetium (Lu)-doped alumina. This study opens up the potential to control the structure and phase composition of Ln-doped alumina for emerging applications.

  16. Structural Effects of Lanthanide Dopants on Alumina

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Ketan; Blair, Victoria; Douglas, Justin; Dai, Qilin; Liu, Yaohua; Ren, Shenqiang; Brennan, Raymond

    2017-01-06

    Lanthanide (Ln3+) doping in alumina has shown great promise for stabilizing and promoting desirable phase formation to achieve optimized physical and chemical properties. However, doping alumina with Ln elements is generally accompanied by formation of new phases (i.e. LnAlO3, Ln2O3), and therefore inclusion of Ln-doping mechanisms for phase stabilization of the alumina lattice is indispensable. In this study, Ln-doping (400 ppm) of the alumina lattice crucially delays the onset of phase transformation and enables phase population control, which is achieved without the formation of new phases. The delay in phase transition (θ → α), and alteration of powder morphology, particle dimensions, and composition ratios between α- and θ-alumina phases are studied using a combination of solid state nuclear magnetic resonance, electron microscopy, digital scanning calorimetry, and high resolution X-ray diffraction with refinement fitting. Loading alumina with a sparse concentration of Ln-dopants suggests that the dopants reside in the vacant octahedral locations within the alumina lattice, where complete conversion into the thermodynamically stable α-domain is shown in dysprosium (Dy)- and lutetium (Lu)-doped alumina. This study opens up the potential to control the structure and phase composition of Ln-doped alumina for emerging applications.

  17. Characterisation of dynamic behaviour of alumina ceramics: evaluation of stress uniformity

    Directory of Open Access Journals (Sweden)

    Zhiyong Wang

    2015-10-01

    Full Text Available Accurate characterisation of dynamic behaviour of ceramics requires the reliable split-Hopkinson pressure bar (SHPB technique and the condition of uniaxial homogeneous specimen deformation. In this study, an experimentally validated 3D finite element model of the full scale SHPB experiment was developed to quantitatively evaluate the wave propagation in the bars and the stress distribution/evolution in the alumina specimen. Wave signals in both the SHPB experiments and the finite element model were analysed to characterise the dynamic behaviour of alumina. It was found that the equilibrium of both stresses within the specimen and forces at the specimen ends can be established in the intermediate stage of deformation. The validity of stress uniformity in the alumina specimen supports the assumption of uniaxial homogeneous specimen deformation in the SHPB and validates the characterisation of dynamic behaviour of alumina ceramics.

  18. Stability of trapped charges in sapphires and alumina ceramics: Evaluation by secondary electron emission

    Science.gov (United States)

    Zarbout, K.; Si Ahmed, A.; Moya, G.; Bernardini, J.; Goeuriot, D.; Kallel, A.

    2008-03-01

    The stability of trapped charges in sapphires and alumina ceramics is characterized via an experimental parameter expressing the variation of the secondary electron emission yield between two electron injections performed in a scanning electron microscope. Two types of sapphires and polycrystalline alumina, which differ mainly by their impurity content, are investigated in the temperature range 300-663K. The stable trapping behavior in sapphires is attributed to trapping in different defects, whose nature depends on the purity level. In alumina ceramics, the ability to trap charges in a stable way is stronger in samples of high impurity content. In the low impurity samples, stable trapping is promoted when the grain diameter decreases, whereas the reverse is observed in high impurity materials. These behaviors can stem from a gettering effect occurring during sintering. The strong dependence of the variation of the secondary electron emission yield on the grain diameter and impurities enables a scaling of the stable trapping ability of alumina materials.

  19. Influence of Alumina Addition on the Optical Property of Zirconia/Alumina Composite Dental Ceramics

    Institute of Scientific and Technical Information of China (English)

    JIANG Li; LIAO Yunmao; LI Wei; WAN Qianbing; ZHAO Yongqi

    2011-01-01

    The influence of various alumina additions on the optical property of zirconia/alumina composite ceramics was investigated.The relative sintered densities,transmittances,color and the microstructure of the composite ceramics were studied.The experimental results showed that the relative sintered densities and transmittances decreased with alumina addition.The lightness increased obviously but the chroma change was small.Pure zirconia nanopowders sintered densely could obtain the relatively high transmittance,while the transmittance and the lightness of slight addition changed significantly.The zirconia/alumina composite ceramics with alumina addition less than 7.5wt% could achieve the relatively stable and reliable optical properties.

  20. Nondiffractive applications of neutrons at the spallation source SINQ

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, E. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1996-11-01

    The paper delivers an overview about experiments with neutrons from the spallation source SINQ which are not especially devoted to neutron scattering. A total of six experimental facilities are under construction using thermal as well as cold neutrons. Starting with some general considerations about the interaction of neutrons with matter, the principles, boundary conditions and the experimental set up of these experiments are described briefly. Some more details are given for the neutron radiography facility NEUTRA as the author`s special interest and research field. (author) 7 figs., 2 tabs., 9 refs.

  1. Numerical modelling of spallation in 2D hydrodynamics codes

    Science.gov (United States)

    Maw, J. R.; Giles, A. R.

    1996-05-01

    A model for spallation based on the void growth model of Johnson has been implemented in 2D Lagrangian and Eulerian hydrocodes. The model has been extended to treat complete separation of material when voids coalesce and to describe the effects of elevated temperatures and melting. The capabilities of the model are illustrated by comparison with data from explosively generated spall experiments. Particular emphasis is placed on the prediction of multiple spall effects in weak, low melting point, materials such as lead. The correlation between the model predictions and observations on the strain rate dependence of spall strength is discussed.

  2. VESPA: The vibrational spectrometer for the European Spallation Source

    Science.gov (United States)

    Fedrigo, Anna; Colognesi, Daniele; Bertelsen, Mads; Hartl, Monika; Lefmann, Kim; Deen, Pascale P.; Strobl, Markus; Grazzi, Francesco; Zoppi, Marco

    2016-06-01

    VESPA, Vibrational Excitation Spectrometer with Pyrolytic-graphite Analysers, aims to probe molecular excitations via inelastic neutron scattering. It is a thermal high resolution inverted geometry time-of-flight instrument designed to maximise the use of the long pulse of the European Spallation Source. The wavelength frame multiplication technique was applied to provide simultaneously a broad dynamic range (about 0-500 meV) while a system of optical blind choppers allows to trade flux for energy resolution. Thanks to its high flux, VESPA will allow the investigation of dynamical and in situ experiments in physical chemistry. Here we describe the design parameters and the corresponding McStas simulations.

  3. Target station shielding issues at the spallation neutron source.

    Science.gov (United States)

    Ferguson, P D; Gallmeier, F X; Iverson, E B; Popova, I I

    2005-01-01

    Recent spallation neutron source shielding activities in support of the neutron beam shutters and the hot cell walls are presented. Existing neutron beam shutters can be replaced with concrete at low power or with concrete and steel at approximately 500 kW of beam power. Potential voids in the hot cell walls are analysed to determine the impact on dose rates as a function of void size. A change in the type of shielding work is noted as the project moved from the early design stages as a 'green field' site to the current stage as a construction project nearing completion, where issues to be addressed are approaching retrofit-type analyses.

  4. Research activities on structure materials of spallation neutron source at SINQ

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, G.S.; Dai, Y. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    With the growing interests on powerful spallation neutron sources, especially with liquid metal targets, and accelerator driven energy systems, spallation materials science and technology have been received wide attention. At SINQ, material research activities are focused on: a) liquid metal corrosion; b) radiation damage; and c) interaction of corrosion and radiation damage. (author) 1 fig., refs.

  5. Design Optimization and the path towards a 2 MW Spallation Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    M. Blaskiewicz; N. Catalan-Lasheras; D. Davino; A. Fedotov; Y. Lee; N. Malitsky; Y. Papaphilippou; D. Raparia; A. Shishlo; N. Tsoupas; J. Wei; W. Weng; S. Zhang; J. Billen; S. Kurennoy; S. Nath; J. Stovall; H. Takeda; L. Young; R. Keller; J. Staples; A. Aleksandrov; Y. Cho; P. Chu; S. Cousineau; V. Danilov; M. Doleans; J. Galambos; J. Holmes; N. Holtkamp; D. Jeon; S. Kim; R. Kustom; E. Tanke; W. Wan; R. Sundelin

    2001-08-01

    The Spallation Neutron Source (SNS) is designed to ultimately reach an average proton beam power of 2 MW for pulsed neutron production. The SNS physics groups analyze the machine performance within the hardware constraints, optimize the accelerator design, and establish the best path towards a 2 MW and higher spallation neutron source.

  6. Desenvolvimento de cerâmicas de mulita a partir de alumina, ácido silícico e aerosil

    OpenAIRE

    Minatti, José Luiz [UNESP

    2009-01-01

    Neste trabalho, apresenta-se uma rota alternativa para produção de cerâmicas de mulita (3Al2O3.2SiO2), a partir da mistura de pós de alumina (Al2O3) e sílica (SiO2), para uma possível aplicação em um dispositivo de perfuração de rochas por jato supersônico quente (thermal spallation). Os pós precursores foram utilizados de dois modos diferentes: no primeiro com tamanho micrométrico, tal como fornecido pelos fabricantes; no segundo, a alumina foi moída e misturada separadamente com ácido silíc...

  7. Oak Ridge Spallation Neutron Source (ORSNS) target station design integration

    Energy Technology Data Exchange (ETDEWEB)

    McManamy, T.; Booth, R.; Cleaves, J.; Gabriel, T. [and others

    1996-06-01

    The conceptual design for a 1- to 3-MW short pulse spallation source with a liquid mercury target has been started recently. The design tools and methods being developed to define requirements, integrate the work, and provide early cost guidance will be presented with a summary of the current target station design status. The initial design point was selected with performance and cost estimate projections by a systems code. This code was developed recently using cost estimates from the Brookhaven Pulsed Spallation Neutron Source study and experience from the Advanced Neutron Source Project`s conceptual design. It will be updated and improved as the design develops. Performance was characterized by a simplified figure of merit based on a ratio of neutron production to costs. A work breakdown structure was developed, with simplified systems diagrams used to define interfaces and system responsibilities. A risk assessment method was used to identify potential problems, to identify required research and development (R&D), and to aid contingency development. Preliminary 3-D models of the target station are being used to develop remote maintenance concepts and to estimate costs.

  8. Generic guide concepts for the European Spallation Source

    CERN Document Server

    Zendler, C; Bentley, P M

    2015-01-01

    The construction of the European Spallation Source (ESS) faces many challenges from the neutron beam transport point of view: The spallation source is specified as being driven by a 5 MW beam of protons, each with 2 GeV energy, and yet the requirements in instrument background suppression relative to measured signal vary between 10$^{-6}$ and 10$^{-8}$. The energetic particles, particularly above 20 MeV, which are expected to be produced in abundance in the target, have to be filtered in order to make the beamlines safe, operational and provide good quality measurements with low background. We present generic neutron guides of short and medium length instruments which are optimized for good performance at minimal cost. Direct line of sight to the source is avoided twice, with either the first point out of line of sight or both being inside the bunker (20\\,m) to minimize shielding costs. These guide geometries are regarded as a baseline to define standards for instruments to be constructed at ESS. They are use...

  9. Superhydrophobicity of Bionic Alumina Surfaces Fabricated by Hard Anodizing

    Institute of Scientific and Technical Information of China (English)

    Jing Li; Feng Du; Xianli Liu; Zhonghao Jiang; Luquan Ren

    2011-01-01

    Bionic alumina samples were fabricated on convex dome type aluminum alloy substrate using hard anodizing technique.The convex domes on the bionic sample were fabricated by compression molding under a compressive stress of 92.5 MPa.The water contact angles of the as-anodized bionic samples were measured using a contact angle meter (JC2000A) with the 3 μL water drop at room temperature.The measurement of the wetting property showed that the water contact angle of the unmodified as-anodized bionic alumina samples increases from 90° to 137° with the anodizing time.The increase in water contract angle with anodizing time arises from the gradual formation of hierarchical structure or composite structure.The structure is composed of the micro-scaled alumina columns and pores.The height of columns and the depth of pores depend on the anodizing time.The water contact angle increases significantly from 96° to 152° when the samples were modified with self-assembled monolayer of octadecanethiol (ODT),showing a change in the wettability from hydrophobicity to super-hydrophobicity.This improvement in the wetting property is attributed to the decrease in the surface energy caused by the chemical modification.

  10. Dissolution Kinetics of Alumina Calcine

    Energy Technology Data Exchange (ETDEWEB)

    Batcheller, Thomas Aquinas

    2001-09-01

    Dissolution kinetics of alumina type non-radioactive calcine was investigated as part of ongoing research that addresses permanent disposal of Idaho High Level Waste (HLW). Calcine waste was produced from the processing of nuclear fuel at the Idaho Nuclear Technology and Engineering Center (INTEC). Acidic radioactive raffinates were solidified at ~500°C in a fluidized bed reactor to form the dry granular calcine material. Several Waste Management alternatives for the calcine are presented in the Idaho High Level Waste Draft EIS. The Separations Alternative addresses the processing of the calcine so that the HLW is ready for removal to a national geological repository by the year 2035. Calcine dissolution is the key front-end unit operation for the separations alternative.

  11. EXPERIMENTAL ANALYSES OF SPALLATION NEUTRONS GENERATED BY 100 MEV PROTONS AT THE KYOTO UNIVERSITY CRITICAL ASSEMBLY

    Directory of Open Access Journals (Sweden)

    CHEOL HO PYEON

    2013-02-01

    Full Text Available Neutron spectrum analyses of spallation neutrons are conducted in the accelerator-driven system (ADS facility at the Kyoto University Critical Assembly (KUCA. High-energy protons (100 MeV obtained from the fixed field alternating gradient accelerator are injected onto a tungsten target, whereby the spallation neutrons are generated. For neutronic characteristics of spallation neutrons, the reaction rates and the continuous energy distribution of spallation neutrons are measured by the foil activation method and by an organic liquid scintillator, respectively. Numerical calculations are executed by MCNPX with JENDL/HE-2007 and ENDF/B-VI libraries to evaluate the reaction rates of activation foils (bismuth and indium set at the target and the continuous energy distribution of spallation neutrons set in front of the target. For the reaction rates by the foil activation method, the C/E values between the experiments and the calculations are found around a relative difference of 10%, except for some reactions. For continuous energy distribution by the organic liquid scintillator, the spallation neutrons are observed up to 45 MeV. From these results, the neutron spectrum information on the spallation neutrons generated at the target are attained successfully in injecting 100 MeV protons onto the tungsten target.

  12. Spallation occurrence from polyamide materials irradiated by thermal plasma with water absorption

    Science.gov (United States)

    Nakano, Tomoyuki; Tanaka, Yasunori; Nakagawa, T.; Shinsei, N.; Uesugi, Y.; Ishijima, T.

    2016-09-01

    This paper first describes the effect of water absorption in polyamide material irradiated by thermal plasmas on the occurrence of spallation phenomena. The interaction between polyamide materials and arc plasmas occurs particularly in the low voltage circuit breaker and aerospace fields. Spallation phenomena are those in which polymer particles are ejected from polymer bulk materials irradiated by high heat flux. To confirm the effect of water absorption into the polyamide material on spallation phenomena, polyamide specimens with and without water absorption were irradiated by Ar inductively coupled thermal plasma. The results show that the polyamide specimen with water absorption ejected spallation particles, whereas the polyamide specimen without water absorption were only slightly ejected, indicating that water absorption promotes the occurrence of spallation. The cooling effects of the spallation polyamide 66 (PA66) particles ablation were also estimated in hot air to assess the arc quenching ability from the spallation particle inclusion. This estimation showed that 10 and more PA66 particles inclusion might decrease the air temperature by 3000 K effectively, which can be useful to enhance arc quenching in circuit breakers working in air.

  13. Recent Development of High Alumina Refractories in China

    Institute of Scientific and Technical Information of China (English)

    WANGJin-xiang; LIUJie-hua

    1994-01-01

    The paper reviews the achievements which have been attained recently in China in high alumina refractories raw materials and their products,including 1) homogenization ,urification and electric fusion of high alumina raw materials and synthesizing of spinel from natural raw materials;2) processing principle and characteristics and microstructural features of creep-resistance high alu-mina brick ,alumina-magnesia-carbon brick and thermal shock resistanced high alumina brikc and their application in practice.

  14. The NNbar Experiment at the European Spallation Source

    CERN Document Server

    Frost, M J

    2016-01-01

    The observation of neutron to antineutron oscillation would be the first experimental evidence to show that baryon number is not a conserved quantity. It also provides an answer to the hypothesized post-sphaleron baryogenesis mechanism shortly after the Big Bang. The free oscillation time {\\tau_{n\\rightarrow\\bar{n}} has a lower limit at 8.7 x 10^7 seconds determined at ILL in 1994. Current beyond Standard Model theories of this oscillation time estimate the value to be on the order of 10^{10} seconds. A new experiment is proposed at the European Spallation Source that has 1000 times the sensitivity of the previous experiment, and would confirm the viability of those beyond Standard Model theories.

  15. Thermal shock analysis of liquid-mercury spallation target

    CERN Document Server

    Ishikura, S; Futakawa, M; Hino, R; Date, H

    2002-01-01

    The developments of the neutron scattering facilities are carried out under the high-intensity proton accelerator project promoted by JAERI and KEK. To estimate the structural integrity of the heavy liquid-metal (Hg) target used as a spallation neutron source in a MW-class neutron scattering facility, dynamic stress behavior due to the incident of a 1 MW-pulsed proton beam was analyzed by using FEM code. Two-type target containers with semi-cylindrical type and flat-plate type window were used as models for analyses. As a result, it is confirmed that the stress (pressure wave) generated by dynamic thermal shock becomes the largest at the center of window, and the flat-plate type window is more advantageous from the structural viewpoint than the semi-cylindrical type window. It has been understood that the stress generated in the window by the pressure wave can be treated as the secondary stress. (author)

  16. Characteristics of the WNR: a pulsed spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Russell, G.J.; Lisowski, P.W.; Howe, S.D.; King, N.S.P.; Meier, M.M.

    1982-01-01

    The Weapons Neutron Research facility (WNR) is a pulsed spallation neutron source in operation at the Los Alamos National Laboratory. The WNR uses part of the 800-MeV proton beam from the Clinton P. Anderson Meson Physics Facility accelerator. By choosing different target and moderator configurations and varying the proton pulse structure, the WNR can provide a white neutron source spanning the energy range from a few MeV to 800 MeV. The neutron spectrum from a bare target has been measured and is compared with predictions using an Intranuclear Cascade model coupled to a Monte Carlo transport code. Calculations and measurements of the neutronics of WNR target-moderator assemblies are presented.

  17. Evolution of a spallation reaction: experiment and Monte Carlo simulation

    CERN Document Server

    Enke, M; Hilscher, D; Jahnke, U; Schapiro, O; Letourneau, A; Galin, J; Goldenbaum, F; Lott, B; Peghaire, A; Filges, D; Neef, R D; Nünnighoff, K; Paul, N; Schaal, H; Sterzenbach, G; Tietze, A; Pienkowski, L

    1999-01-01

    Reaction cross sections and production cross sections for neutrons, hydrogen, and helium have been measured for 1.2, 1.8 GeV p+Fe, Ni, Ag, Ta, W, Au, Pb and U and are compared with different intra-nuclear-cascade- combined with evaporation-models. Agreement for neutrons and considerable differences for light charged particles are observed between experiment and calculation as well as between different models. The discrepancies are associated with specific deficiencies in the models. The exclusive data measured with two 4 pi-detectors for neutron and charged particle detection allowed furthermore a systematic comparison of observables characteristic of different stages of the temporal evolution of a spallation reaction: inelastic collision probability, excitation energy distribution, pre-equilibrium emission, and inclusive production cross sections.

  18. BEAM INSTRUMENTATION FOR THE SPALLATION NEUTRON SOURCE RING.

    Energy Technology Data Exchange (ETDEWEB)

    WITKOVER,R.L.; CAMERON,P.R.; SHEA,T.J.; CONNOLLY,R.C.; KESSELMAN,M.

    1999-03-29

    The Spallation Neutron Source (SNS) will be constructed by a multi-laboratory collaboration with BNL responsible for the transfer lines and ring. [1] The 1 MW beam power necessitates careful monitoring to minimize un-controlled loss. This high beam power will influence the design of the monitors in the high energy beam transport line (HEBT) from linac to ring, in the ring, and in the ring-to-target transfer line (RTBT). The ring instrumentation must cover a 3-decade range of beam intensity during accumulation. Beam loss monitoring will be especially critical since un-controlled beam loss must be kept below 10{sup -4}. A Beam-In-Gap (BIG) monitor is being designed to assure out-of-bucket beam will not be lost in the ring.

  19. Room-temperature LINAC structures for the spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Billen, J. H. (James H.); Young, L. M. (Lloyd M.); Kurennoy, S. (Sergey); Crandall, K. R. (Kenneth R.)

    2001-04-01

    Los Alamos National Laboratory is building room-temperature rf accelerating structures for the Spallation Neutron Source (SNS). These structures, for H{sup -} ions, consist of six 402.5-MHz, 2-MW drift-tube linac (DTL) tanks from 2.5 to 87 MeV followed by four 805-MHz, 4-MW coupled-cavity linac (CCL) modules to 186 MeV. The DTL uses permanent magnet quadrupoles inside the drift tubes arranged in a 6{beta}{lambda} FFODDO lattice with every third drift tube available for diagnostics and steering. The CCL uses a 13{beta}{lambda} FODO electromagnetic quadrupole lattice. Diagnostics and magnets occupy the 2.5{beta}{lambda} spaces between 8-cavity segments. This paper discusses design of the rf cavities and low-power modeling work.

  20. The Spallation Neutron Source Beam Commissioning and Initial Operations

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, Stuart [Argonne National Lab. (ANL), Argonne, IL (United States); Aleksandrov, Alexander V. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Allen, Christopher K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Assadi, Saeed [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bartoski, Dirk [University of Texas, Houston, TX (United States). Anderson Cancer Center; Blokland, Willem [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Casagrande, F. [Michigan State Univ., East Lansing, MI (United States); Campisi, I. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Chu, C. [Michigan State Univ., East Lansing, MI (United States); Cousineau, Sarah M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Crofford, Mark T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Danilov, Viatcheslav [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Deibele, Craig E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Dodson, George W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Feshenko, A. [Inst. for Nuclear Research (INR), Moscow (Russian Federation); Galambos, John D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Han, Baoxi [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hardek, T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Holmes, Jeffrey A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Holtkamp, N. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Howell, Matthew P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jeon, D. [Inst. for Basic Science, Daejeon (Korea); Kang, Yoon W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kasemir, Kay [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kim, Sang-Ho [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kravchuk, L. [Institute for Nuclear Research (INR), Moscow (Russian Federation); Long, Cary D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); McManamy, T. [McManamy Consulting, Inc., Middlesex, MA (United States); Pelaia, II, Tom [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Piller, Chip [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Plum, Michael A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pogge, James R. [Tennessee Technological Univ., Cookeville, TN (United States); Purcell, John David [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shea, T. [European Spallation Source, Lund (Sweden); Shishlo, Andrei P [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sibley, C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Stockli, Martin P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Stout, D. [Michigan State Univ., East Lansing, MI (United States); Tanke, E. [European Spallation Source, Lund (Sweden); Welton, Robert F [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Zhang, Y. [Michigan State Univ., East Lansing, MI (United States); Zhukov, Alexander P [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-09-01

    The Spallation Neutron Source (SNS) accelerator delivers a one mega-Watt beam to a mercury target to produce neutrons used for neutron scattering materials research. It delivers ~ 1 GeV protons in short (< 1 us) pulses at 60 Hz. At an average power of ~ one mega-Watt, it is the highest-powered pulsed proton accelerator. The accelerator includes the first use of superconducting RF acceleration for a pulsed protons at this energy. The storage ring used to create the short time structure has record peak particle per pulse intensity. Beam commissioning took place in a staged manner during the construction phase of SNS. After the construction, neutron production operations began within a few months, and one mega-Watt operation was achieved within three years. The methods used to commission the beam and the experiences during initial operation are discussed.

  1. Alumina Carbon Refractory Products for Continuous Casting

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ 1 Scope This standard specifies the classification.techni-cal requirements,test methods,inspection rules,packing,marking,transportation,storage and quality certificate of alumina carbon refractory products for continuous casting.

  2. Loss tangent measurements on unirradiated alumina

    Energy Technology Data Exchange (ETDEWEB)

    Zinkle, S.J.; Goulding, R.H. [Oak Ridge National Lab., TN (United States)

    1996-04-01

    Unirradiated room temperature loss tangent for sapphire and several commercial grades of polycrystalline alumina are complied for frequencies between 10{sup 5} and 4x10{sup 11} Hz. Sapphire exhibits significantly lower values for the loss tangent at frequencies up to 10{sup 11} Hz. The loss tangents of 3 different grades of Wesgo alumina (AL300, AL995, AL998) and 2 different grades of Coors alumina (AD94, AD995) have typical values near {approx}10{sup -4} at a frequency of 10{sup 8} Hz. On the other hand, the loss tangent of Vitox alumina exhibits a large loss peak tan d{approx} 5x10{sup -3} at this frequency.

  3. Burned Microporous Alumina-Graphite Brick

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ 1 Scope This standard specifies the definition,classifica-tion,technical requirements,test methods,inspection rules,marking,packing,transportation and quality certificate of burned microporous alumina-graphite brick.

  4. Overview of the Conceptual Design of the Future VENUS Neutron Imaging Beam Line at the Spallation Neutron Source

    Science.gov (United States)

    Bilheux, Hassina; Herwig, Ken; Keener, Scott; Davis, Larry

    VENUS (Versatile Neutron Imaging Beam line at the Spallation Neutron Source) will be a world-class neutron-imaging instrument that will uniquely utilize the Spallation Neutron Source (SNS) time-of-flight (TOF) capabilities to measure and characterize objects across several length scales (mm to μm). When completed, VENUS will provide academia, industry and government laboratories with the opportunity to advance scientific research in areas such as energy, materials, additive manufacturing, geosciences, transportation, engineering, plant physiology, biology, etc. It is anticipated that a good portion of the VENUS user community will have a strong engineering/industrial research focus. Installed at Beam line 10 (BL10), VENUS will be a 25-m neutron imaging facility with the capability to fully illuminate (i.e., umbra illumination) a 20 cm x 20 cm detector area. The design allows for a 28 cm x 28 cm field of view when using the penumbra to 80% of the full illumination flux. A sample position at 20 m will be implemented for magnification measurements. The optical components are comprised of a series of selected apertures, T0 and bandwidth choppers, beam scrapers, a fast shutter to limit sample activation, and flight tubes filled with Helium. Techniques such as energy selective, Bragg edge and epithermal imaging will be available at VENUS.

  5. Mercury purification in the megawatt liquid metal spallation target of EURISOL-DS

    CERN Document Server

    Neuhausen, Joerg; Eller, Martin; Schumann, Dorothea; Eichler, Bernd; Horn, Susanne

    High power spallation targets are going to be used extensively in future research and technical facilities such as spallation neutron sources, neutrino factories, radioactive beam facilities or accelerator driven systems for the transmutation of long-lived nuclear waste. Within EURISOL-DS, a 4 MW liquid metal spallation target is designed to provide neutrons for a fission target, where neutron rich radionuclides will be produced. For the spallation target, mercury is planned to be used as target material. A large amount of radionuclides ranging from atomic number Z=1 to 81 will be produced in the liquid metal during long term irradiation. It is planned to remove those radionuclides by chemical or physicochemical methods to reduce its radioactivity. For the development of a purification procedure, knowledge about the chemical state of the different elements present in the mixture is required. We present a general concept of applicable separation techniques in a target system and show some results of experiment...

  6. Direct foaming porous alumina ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Salvini, V.R.; Sandurkov, B.A.; Klein-Gunnewiek, R.F.; Pandolfelli, V.C. [Federal Univ. of Sao Carlos, Materials Engineering Dept., FIRE Associate Lab., Sao Carlos, SP (Brazil)

    2007-07-01

    This paper presents the work carried out in order to improve the properties of these porous alumina ceramics, concerning their application as thermal insulating. Changes in solid content of ceramic suspension, variations of pore forming agents and other additives were carried out and their effects on the green and the sintered mechanical strength are also shown. According to the literature, several starch types seem to be attractive pore forming agents as well as binders for porous ceramics. Most of them consist of a mixture of two polysaccharide types, amylose (linear) and amylopectin (highly branched). Corn, potato and rice starches were used in the present study because of their difference in size and shape. In order to increase the mechanical strength of the sintered porous ceramics a part of the Al{sub 2}O{sub 3} in the composition was replaced by Al(OH){sub 3}. Due to the changes of the composition and additives, porosities up to 81% and a mechanical strength of 15 MPa were obtained. (orig.)

  7. Enhanced gas separation factors of microporous polymer constrained in the channels of anodic alumina membranes

    Science.gov (United States)

    Chernova, Ekaterina; Petukhov, Dmitrii; Boytsova, Olga; Alentiev, Alexander; Budd, Peter; Yampolskii, Yuri; Eliseev, Andrei

    2016-08-01

    New composite membranes based on porous anodic alumina films and polymer of intrinsic microporosity (PIM-1) have been prepared using a spin-coating technique. According to scanning electron microscopy, partial penetration of polymer into the pores of alumina supports takes place giving rise to selective polymeric layers with fiber-like microstructure. Geometric confinement of rigid PIM-1 in the channels of anodic alumina causes reduction of small-scale mobility in polymeric chains. As a result, transport of permanent gases, such as CH4, becomes significantly hindered across composite membranes. Contrary, the transport of condensable gases (CO2, C4H10), did not significantly suffer from the confinement due to high solubility in the polymer matrix. This strategy enables enhancement of selectivity towards CO2 and C4H10 without significant loss of the membrane performance and seems to be prospective for drain and sweetening of natural gas.

  8. Device for Writing the Time Tail from Spallation Neutron Pulses

    Energy Technology Data Exchange (ETDEWEB)

    Langan, P. (Paul); Schoenborn, Benno P.; Langan, P. (Paul); Schoenborn, Benno P.; Daemen, L. L. (Luc L.)

    2001-01-01

    Recent work at Los Alamos Neutron Science Center (LANSCE), has shown that there are large gains in neutron beam intensity to be made by using coupled moderators at spallation neutron sources. Most of these gains result from broadening the pulse-width in time. However the accompanying longer exponential tail at large emission times can be a problem in that it introduces relatively large beam-related backgrounds at high resolutions. We have designed a device that can reshape the moderated neutron beam by cutting the time-tail so that a sharp time resolution can be re-established without a significant loss in intensity. In this work the basic principles behind the tail-cutter and some initial results of Monte Carlo simulations are described. Unwanted neutrons in the long time-tail are diffracted out of the transmitted neutron beam by a nested stack of aperiodic multi-layers, rocking at the same frequency as the source. Nested aperiodic multi-layers have recently been used at X-ray sources and as band-pass filters in quasi-Laue neutron experiments at reactor neutron sources. Optical devices that rock in synchronization with a pulsed neutron beam are relatively new but are already under construction at LANSCE. The tail-cutter described here is a novel concept that uses existing multi-layer technology in a new way for spallation neutrons. Coupled moderators in combination with beam shaping devices offer the means of increasing flux whilst maintaining a sharp time distribution. A prototype device is being constructed for the protein crystallography station at LANSCE. The protein crystallography station incorporates a water moderator that has been judiciously coupled in order to increase the flux over neutron energies that are important to structural biology (3-80meV). This development in moderator design is particularly important because protein crystallography is flux limited and because conventional ambient water and cold hydrogen moderators do not provide relatively

  9. Overview of the conceptual design of the future VENUS beamline at the Spallation Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Bilheux, Hassina Z [ORNL; Herwig, Kenneth W [ORNL; Keener, Wylie S [ORNL; Davis, Larry E [ORNL

    2015-01-01

    VENUS will be a world-class neutron-imaging instrument that will uniquely utilize the Spallation Neutron Source (SNS) time-of-flight (TOF) capabilities to measure and characterize objects across several length scales (mm to m). When completed, VENUS will provide academia, industry and government laboratories with the opportunity to advance scientific research in areas such as energy, materials, additive manufacturing, geosciences, transportation, engineering, plant physiology, biology, etc. It is anticipated that a good portion of the VENUS user community will have a strong engineering/industrial research focus. Installed at Beamline 10 (BL10), VENUS will be a 25-m neutron imaging facility with the capability to fully illuminate (i.e., umbra illumination) a 20 cm x 20 cm detector area. The design allows for a 28 cm x 28 cm field of view when using the penumbra to 80% of the full illumination flux. A sample position at 20 m will be implemented for magnification measurements. The optical components are comprised of a series of selected apertures, T0 and bandwidth choppers, beam scrapers, a fast shutter to limit sample activation, and flight tubes filled with Helium. Techniques such as energy selective, Bragg edge and epithermal imaging will be available at VENUS

  10. Improvements to the internal and external antenna H(-) ion sources at the Spallation Neutron Source.

    Science.gov (United States)

    Welton, R F; Dudnikov, V G; Han, B X; Murray, S N; Pennisi, T R; Pillar, C; Santana, M; Stockli, M P; Turvey, M W

    2014-02-01

    The Spallation Neutron Source (SNS), a large scale neutron production facility, routinely operates with 30-40 mA peak current in the linac. Recent measurements have shown that our RF-driven internal antenna, Cs-enhanced, multi-cusp ion sources injects ∼55 mA of H(-) beam current (∼1 ms, 60 Hz) at 65-kV into a Radio Frequency Quadrupole (RFQ) accelerator through a closely coupled electrostatic Low-Energy Beam Transport system. Over the last several years a decrease in RFQ transmission and issues with internal antennas has stimulated source development at the SNS both for the internal and external antenna ion sources. This report discusses progress in improving internal antenna reliability, H(-) yield improvements which resulted from modifications to the outlet aperture assembly (applicable to both internal and external antenna sources) and studies made of the long standing problem of beam persistence with the external antenna source. The current status of the external antenna ion source will also be presented.

  11. Monitoring Transport Across Modified Nanoporous Alumina Membranes

    Directory of Open Access Journals (Sweden)

    Erich D. Steinle

    2007-11-01

    Full Text Available This paper describes the use of several characterization methods to examinealumina nanotubule membranes that have been modified with specific silanes. The functionof these silanes is to alter the transport properties through the membrane by changing thelocal environment inside the alumina nanotube. The presence of alkyl groups, either long(C18 or short and branched (isopropyl hydrocarbon chains, on these silanes significantlydecreases the rate of transport of permeant molecules through membranes containingalumina nanotubes as monitored via absorbance spectroscopy. The presence of an ionicsurfactant can alter the polarity of these modified nanotubes, which correlates to anincreased transport of ions. Fluorescent spectroscopy is also utilized to enhance thesensitivity of detecting these permeant molecules. Confirmation of the alkylsilaneattachment to the alumina membrane is achieved with traditional infrared spectroscopy,which can also examine the lifetime of the modified membrane. The physical parameters ofthese silane-modified porous alumina membranes are studied via scanning electronmicroscopy. The alumina nanotubes are not physically closed off or capped by the silanesthat are attached to the alumina surfaces.

  12. High contrast laser marking of alumina

    Energy Technology Data Exchange (ETDEWEB)

    Penide, J. [Applied Physics Department, University of Vigo, EEI, Lagoas-Marcosende, 9, Vigo 36310 (Spain); Quintero, F., E-mail: fquintero@uvigo.es [Applied Physics Department, University of Vigo, EEI, Lagoas-Marcosende, 9, Vigo 36310 (Spain); Riveiro, A. [Applied Physics Department, University of Vigo, EEI, Lagoas-Marcosende, 9, Vigo 36310 (Spain); Fernández, A. [Department of Engineering Design, University of Vigo, Escuela de Ingeniería Industrial, Campus Universitario, Vigo E-36310 (Spain); Val, J. del [Applied Physics Department, University of Vigo, EEI, Lagoas-Marcosende, 9, Vigo 36310 (Spain); Comesaña, R. [Materials Engineering, Applied Mechanics and Construction Department, University of Vigo, EEI, Lagoas-Marcosende, Vigo E-36310 (Spain); Lusquiños, F.; Pou, J. [Applied Physics Department, University of Vigo, EEI, Lagoas-Marcosende, 9, Vigo 36310 (Spain)

    2015-05-01

    Highlights: • Laser marking of alumina using near infrared (NIR) lasers was experimentally analyzed. • Color change produced by NIR lasers is due to thermally induced oxygen vacancies. • Laser marking results obtained using NIR lasers and green laser are compared. • High contrast marks on alumina were achieved. - Abstract: Alumina serves as raw material for a broad range of advanced ceramic products. These elements should usually be identified by some characters or symbols printed directly on them. In this sense, laser marking is an efficient, reliable and widely implemented process in industry. However, laser marking of alumina still leads to poor results since the process is not able to produce a dark mark, yielding bad contrast. In this paper, we present an experimental study on the process of marking alumina by three different lasers working in two wavelengths: 1064 nm (Near-infrared) and 532 nm (visible, green radiation). A colorimetric analysis has been carried out in order to compare the resulting marks and its contrast. The most suitable laser operating conditions were also defined and are reported here. Moreover, the physical process of marking by NIR lasers is discussed in detail. Field Emission Scanning Electron Microscopy, High Resolution Transmission Electron Microscopy and X-ray Photoelectron Spectroscopy were also employed to analyze the results. Finally, we propose an explanation for the differences of the coloration induced under different atmospheres and laser parameters. We concluded that the atmosphere is the key parameter, being the inert one the best choice to produce the darkest marks.

  13. Bioactive glass-ceramics coatings on alumina

    Energy Technology Data Exchange (ETDEWEB)

    Vitale Brovarone, C.; Verne, E.; Lupo, F. [Politecnico di Torino (Italy). Materials Science and Chemical Eng. Dept.; Moisescu, C. [Jena Univ. (Germany). Otto-Schott-Inst. fuer Glaschemie; Zanardi, L.; Bosetti, M.; Cannas, M. [Eastern Piemont Univ., Novara (Italy). Medical Science Dept.

    2001-07-01

    In this work, aiming to combine the mechanical performances of alumina with the surface properties of a bioactive material, we coated full density alumina substrates by a bioactive glass-ceramic GC. This latter was specially tailored, in term of costituents and specific quantity to have a thermal expansion coefficient close to that of alumina (8.5-9{sup *}10{sup -6}/ C) which is lower than most of the bioactive glasses and glass-ceramics already in use. In this way, we sought to avoid, as much as possible, the crack formation and propagation due to residual stresses generated by the thermal expansion coefficients mismatch. Furthermore, the high reactivity of alumina toward the glass-ceramic was carefully controlled to avoid deep compositional modification of the GC that will negatively affect its bioactivity. At this purpose, an intermediate layer of an appropriate glass G was coated prior to coat the bioactive glass-ceramic. On the materials obtained, preliminary biological tests have been done to evaluate glass-ceramic biocompatibility respect to alumina. (orig.)

  14. Dielectric Performance of a High Purity HTCC Alumina at High Temperatures - a Comparison Study with Other Polycrystalline Alumina

    Science.gov (United States)

    Chen, Liangyu

    2014-01-01

    A very high purity (99.99+%) high temperature co-fired ceramic (HTCC) alumina has recently become commercially available. The raw material of this HTCC alumina is very different from conventional HTCC alumina, and more importantly there is no glass additive in this alumina material for co-firing processing. Previously, selected HTCC and LTCC (low temperature co-fired ceramic) alumina materials were evaluated at high temperatures as dielectric and compared to a regularly sintered 96% polycrystalline alumina (96% Al2O3), where 96% alumina was used as the benchmark. A prototype packaging system based on regular 96% alumina with Au thickfilm metallization successfully facilitated long term testing of high temperature silicon carbide (SiC) electronic devices for over 10,000 hours at 500 C. In order to evaluate this new high purity HTCC alumina for possible high temperature packaging applications, the dielectric properties of this HTCC alumina substrate were measured and compared with those of 96% alumina and a previously tested LTCC alumina from room temperature to 550 C at frequencies of 120 Hz, 1 KHz, 10 KHz, 100 KHz, and 1 MHz. A parallel-plate capacitive device with dielectric of the HTCC alumina and precious metal electrodes were used for measurements of the dielectric constant and dielectric loss of the co-fired alumina material in the temperature and frequency ranges. The capacitance and AC parallel conductance of the capacitive device were directly measured by an AC impedance meter, and the dielectric constant and parallel AC conductivity of the dielectric were calculated from the capacitance and conductance measurement results. The temperature and frequency dependent dielectric constant, AC conductivity, and dissipation factor of the HTCC alumina substrate are presented and compared to those of 96% alumina and a selected LTCC alumina. Other technical advantages of this new co-fired material for possible high packaging applications are also discussed.

  15. ENGINEERING DESIGN OF THE EURISOL MULTI-MW SPALLATION TARGET

    CERN Document Server

    Adonai Herrera-Martinez*, Yacine Kadi, Morteza Ashrafi-Nik, Karel Samec, Janis Freibergs, Ernests Platacis

    The European Isotope Separation On-Line Radioactive Ion Beam project (EURISOL) is set to design the ‘next-generation’ European Isotope Separation On-Line (ISOL) Radioactive Ion Beam (RIB) facility. It will extend and amplify current research on nuclear physics, nuclear astrophysics and fundamental interactions beyond the year 2010. In EURISOL, four target stations are foreseen, three direct targets of approximately 100 kW of beam power and one multi-MW target assembly, all driven by a high-power particle accelerator. In this high power target station, high-intensity RIBs of neutron-rich isotopes will be obtained by inducing fission in several actinide targets surrounding a liquid metal spallation neutron source. This article summarises the work carried out within Task 2 of the EURISOL Design Study, with special attention to the coupled neutronics of the mercury proton-to-neutron converter and the fission targets. The overall performance of the facility, which will sustain fast neutron fluxes of the order ...

  16. Engineering design of the EURISOL multi-MW spallation target

    CERN Document Server

    Herrera-Martínez, A; Ashrafi-Nik, M; Samec, K; Freibergs, J; Platacis, E

    2007-01-01

    The European Isotope Separation On-Line Radioactive Ion Beam project (EURISOL) is set to design the 'next-generation' European Isotope Separation On-Line (ISOL) Radioactive Ion Beam (RIB) facility. It will extend and amplify current research on nuclear physics, nuclear astrophysics and fundamental interactions beyond the year 2010. In EURISOL, four target stations are foreseen, three direct targets of approximately 100 kW of beam power and one multi-MW target assembly, all driven by a high-power particle accelerator. In this high power target station, high-intensity RIBs of neutron-rich isotopes will be obtained by inducing fission in several actinide targets surrounding a liquid metal spallation neutron source. This article summarises the work carried out within Task 2 of the EURISOL Design Study, with special attention to the coupled neutronics of the mercury proton-to-neutron converter and the fission targets. The overall performance of the facility, which will sustain fast neutron fluxes of the order of 1...

  17. Beam dynamics simulation of the Spallation Neutron Source linear accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, H.; Billen, J.H.; Bhatia, T.S.

    1998-12-31

    The accelerating structure for Spallation Neutron Source (SNS) consists of a radio-frequency-quadrupole-linac (RFQ), a drift-tube-linac (DTL), a coupled-cavity-drift-tube-linac (CCDTL), and a coupled-cavity-linac (CCL). The linac is operated at room temperature. The authors discuss the detailed design of linac which accelerates an H{sup {minus}} pulsed beam coming out from RFQ at 2.5 MeV to 1000 MeV. They show a detailed transition from 402.5 MHz DTL with a 4 {beta}{lambda} structure to a CCDTL operated at 805 MHz with a 12 {beta}{lambda} structure. After a discussion of overall feature of the linac, they present an end-to-end particle simulation using the new version of the PARMILA code for a beam starting from the RFQ entrance through the rest of the linac. At 1000 MeV, the beam is transported to a storage ring. The storage ring requires a large ({+-}500-keV) energy spread. This is accomplished by operating the rf-phase in the last section of the linac so the particles are at the unstable fixed point of the separatrix. They present zero-current phase advance, beam size, and beam emittance along the entire linac.

  18. rf improvements for Spallation Neutron Source H-ion source

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Yoon W [ORNL; Fuja, Raymond E [ORNL; Goulding, Richard Howell [ORNL; Hardek, Thomas W [ORNL; Lee, Sung-Woo [ORNL; McCarthy, Mike [ORNL; Piller, Chip [ORNL; Shin, Ki [ORNL; Stockli, Martin P [ORNL; Welton, Robert F [ORNL

    2010-01-01

    The Spallation Neutron Source at Oak Ridge National Laboratory is ramping up the accelerated proton beam power to 1.4 MW and just reached 1 MW. The rf-driven multicusp ion source that originates from the Lawrence Berkeley National Laboratory has been delivering 38 mA H beam in the linac at 60 Hz, 0.9 ms. To improve availability, a rf-driven external antenna multicusp ion source with a water-cooled ceramic aluminum nitride AlN plasma chamber is developed. Computer modeling and simulations have been made to analyze and optimize the rf performance of the new ion source. Operational statistics and test runs with up to 56 mA medium energy beam transport beam current identify the 2 MHz rf system as a limiting factor in the system availability and beam production. Plasma ignition system is under development by using a separate 13 MHz system. To improve the availability of the rf power system with easier maintenance, we tested a 70 kV isolation transformer for the 80 kW, 6% duty cycle 2 MHz amplifier to power the ion source from a grounded solid-state amplifier. 2010 American Institute of Physics.

  19. Scattering effect in proton beam windows at spallation targets

    CERN Document Server

    Meng, C; Jing, H T

    2010-01-01

    Proton beam window (PBW) is a boundary wall between a high vacuum area in the proton beam line and the helium atmosphere in a helium vessel at a high beam power target. The thermal and mechanical problems of the PBW have been studied in other spallation neutron sources; however, the scattering effect in PBW is seldom reported in literature but it may pose serious problems for the target design if not well treated. This paper will report the simulation studies of the scattering effect in PBW. Different materials and different structures of PBW are discussed. Taking CSNS as an example, a thin single-layer aluminum alloy PBW with edge cooling has been chosen for CSNS-I and CSNS-II, and a sandwiched aluminum alloy PBW has been chosen for CSNS-III. Simulations results of the scattering effect in the presence of beam uniformization at target by using non-linear magnets at the different CSNS PBWs are presented. The simulations show that the scattering effect at PBW is very important in the beam loss and the beam dis...

  20. The COHERENT Experiment at the Spallation Neutron Source

    CERN Document Server

    Akimov, D; Awe, C; Barbeau, P S; Barton, P; Becker, B; Below, V; Bolozdynya, A; Burenkov, A; Cabrera-Palmer, B; Collar, J I; Cooper, R J; Cooper, R L; Cuesta, C; Dean, D; Detwiler, J; Efremenko, Y; Elliott, S R; Fields, N; Fox, W; Galindo-Uribarri, A; Green, M; Heath, M; Hedges, S; Herman, N; Hornback, D; Iverson, E B; Kaufman, L; Klein, S R; Khromov, A; Konovalev, A; Kumpan, A; Leadbetter, C; Li, L; Lu, W; Melikyan, A; Markoff, D; Miller, K; Middlebrook, M; Mueller, P; Naumov, P; Newby, J; Parno, D; Penttila, S; Perumpilly, G; Radford, D; Ray, H; Raybern, J; Reyna, D; Rich, G C; Rimal, D; Rudik, D; Scholberg, K; Scholz, B; Snow, W M; Sosnovchev, A; Shakirov, A; Suchyta, S; Suh, B; Tayloe, R; Thornton, R T; Tolstukhin, A; Vetter, K; Yu, C H

    2015-01-01

    The COHERENT collaboration's primary objective is to measure coherent elastic neutrino-nucleus scattering (CEvNS) using the unique, high-quality source of tens-of-MeV neutrinos provided by the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL). In spite of its large cross section, the CEvNS process has never been observed, due to tiny energies of the resulting nuclear recoils which are out of reach for standard neutrino detectors. The measurement of CEvNS has now become feasible, thanks to the development of ultra-sensitive technology for rare decay and weakly-interacting massive particle (dark matter) searches. The CEvNS cross section is cleanly predicted in the standard model; hence its measurement provides a standard model test. It is relevant for supernova physics and supernova-neutrino detection, and enables validation of dark-matter detector background and detector-response models. In the long term, precision measurement of CEvNS will address questions of nuclear structure. COHERENT...

  1. Mechanical Engineering of the Linac for the Spallation Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Bultman, N.K.; Chen, Z.; Collier, M.; Erickson, J.L.; Guthrie, A.; Hunter, W.T.; Ilg, T.; Meyer, R.K.; Snodgrass, N.L.

    1999-03-29

    The linac for the Spallation Neutron Source (SNS) Project will accelerate an average current of 1 mA of H{sup {minus}} ions from 20 MeV to 1GeV for injection into an accumulator ring. The linac will be an intense source of H{sup {minus}} ions and as such requires advanced design techniques to meet project technical goals as well as to minimize costs. The DTL, CCDTL and CCL are 466m long and operate at 805 MHz with a maximum H{sup {minus}} input current of 28 mA and 7% rf duty factor. The Drift Tube Linac is a copper-plated steel structure using permanent magnetic quadrupoles. The Coupled-Cavity portions are brazed copper structures and use electromagnetic quads. RF losses in the copper are 80 MW, with total rf power supplied by 52 klystrons. Additionally, the linac is to be upgraded to the 2- and 4-MW beam power levels with no increase in duty factor. The authors give an overview of the linac mechanical engineering effort and discuss the special challenges and status of the effort.

  2. Neutron diffractometers for structural biology at spallation neutron sources

    Energy Technology Data Exchange (ETDEWEB)

    Schoenborn, B.P.; Pitcher, E. [Los Alamos National Laboratory, NM (United States)

    1994-12-31

    Spallation neutron sources are ideal for diffraction studies of proteins and oriented molecular complexes. With spoliation neutrons and their time dependent wavelength structure, it is easy to electronically select data with an optimal wavelength bandwidth and cover the whole Laue spectrum as time (wavelength) resolved snapshots. This optimized data quality with best peak-to-background ratios and provides adequate spatial and energy resolution to eliminate peak overlaps. The application of this concept will use choppers to select the desired Laue wavelength spectrum and employ focusing optics and large cylindrical {sup 3}He detectors to optimize data collection rates. Such a diffractometer will cover a Laue wavelength range from 1 to 5{Angstrom} with a flight path length of 10m and an energy resolution of 0.25{Angstrom}. Moderator concepts for maximal flux distribution within this energy range will be discussed using calculated flux profiles. Since the energy resolution required for such timed data collection in this super Laue techniques is not very high, the use of a linac only (LAMPF) spoliation target is an exciting possibility with an order of magnitude increase in flux.

  3. Fission and spallation data evaluation using induced-activity method

    CERN Document Server

    Karapetyan, G S

    2015-01-01

    The induced-activity investigations in off-line analysis performed in different experiments, concerning pre-actinide and actinide nuclei, are here presented and discussed. Generalized expressions for the determination of independent yields/cross sections of radioactive nuclei, formed in the targets, are derived and analysed. The fragment mass distribution from U-238, Th-232 and Ta-181 photofission at the bremsstrahlung end-point energies of 50 and 3500 MeV, and from Am-241, U-238 and Np-237 fission induced by 660-MeV protons, are scrutinized from the point of view of the multimodal fission approach. The results of these studies are hence compared with theoretical model calculations using the CRISP code. We subsequently discuss the complex particle-induced reaction, such as heavy-ions and deuterons, by using the thick-target thick-catcher technique and the two-step vector model framework as well. This is accomplished in order to present the investigation of the main processes (fission, spallation and (multi)fr...

  4. A High Intensity Linac for the National Spallation Neutron Source

    Science.gov (United States)

    Jason, A.; Bhatia, T.; Billen, J.; Schrage, D.; Kurennoy, S.; Krawczyk, F.; Lynch, M.; Nath, S.; Shafer, R.; Takeda, H.; Tallerico, P.; Wangler, T.; Wood, R.; Young, L.; Grand, P.; McKenzie-Wilson, R.

    1997-05-01

    The National Spallation Neutron Source to be constructed at Oak Ridge National Laboratory, requires a linac capable of delivering up to 5 MW of beam power to an accumulator ring with a nominal 6.2% duty factor and an energy of 1 GeV. Los Alamos, responsible for the linac design, has developed an appropriate room-temperature linac that consists of a drift-tube section from 2.5 to 20 MeV, a coupled-cavity drift-tube section to 100 MeV, and a coupled-cavity section to 1 GeV. The initial scenario requires an average 1.1-mA beam current with a corresponding 28 mA peak current and a 1.2-Mhz chopped time structure corresponding to the ring period. Upgrade to a 4.4 mA average current requires funneling with a peak current of 112 mA in the high-energy sections. Further parameters are presented along with beam dynamics and structure choices and mechanical and rf engineering considerations.

  5. Synthesis and characterization of alumina precursor and alumina to be used as nano composite; Sintese e caracterizacao de precursores de alumina e alumina para uso em nanocompositos

    Energy Technology Data Exchange (ETDEWEB)

    Antunes, M.L.P., E-mail: malu@sorocaba.unesp.b [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Sorocaba, SP (Brazil); Santos, H. Souza [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica; Santos, P. Souza [Universidade de Sao Paulo (EP/USP), SP (Brazil). Escola Politecnica

    2009-07-01

    With the evolution of nanomaterials technology, mainly in the 90s, it was possible to observe produced composites with alumina matrix and nanomaterial as reinforcing materials. It results in a significant improvement of mechanical proprieties of these composites. Thenceforth the study of synthesis and characterization of nanostructured materials has attracted great scientific interest. In this perspective, the aim of this work is to present an experimental procedure to obtain nordstrandite (aluminum hydroxide) with nanometric dimensions. Nordstrandite synthesis, obtained by the reaction of slightly amalgamated aluminum foil with aqueous ethylene glycol, which allows the control of the size of crystal produced. This control could be confirmed by X-Ray Diffraction and Electron Microscopy. Thermal transformation study is also presented. This study allowed the identification of transition aluminas that have potential to produce nanometric aluminas. (author)

  6. Dynamical Mechanical Properties for AD90 Alumina

    Institute of Scientific and Technical Information of China (English)

    REN Hui-lan; NING Jian-guo; LI Ping

    2007-01-01

    The dynamic response of polycrystalline alumina was investigated in the pressure range of 0 -13 GPa by planar impact experiments.Velocity interferometer system for any reflector(VISAR) was used to obtain free surface velocity profile and determine the Hugoniot elastic limit,and manganin gauges were employed to obtain the stress-time histories and determine Hugoniot curve.Both the free surface particle velocity profiles and Hugoniot curves indicate the dispersion of the "plastic" wave for alumina.With the measured stress histories,the complete histories of strain,particle velocity,specific volume and specific internal energy are gained by using path line principle of Lagrange analysis.The dynamic mechanical behaviors for alumina under impact loading are analyzed,such as nonlinear characteristic,strain rate dependence,dispersion and declination of shock wave in the material.

  7. Iron films deposited on porous alumina substrates

    Science.gov (United States)

    Yamada, Yasuhiro; Tanabe, Kenichi; Nishida, Naoki; Kobayashi, Yoshio

    2016-12-01

    Iron films were deposited on porous alumina substrates using an arc plasma gun. The pore sizes (120 - 250 nm) of the substrates were controlled by changing the temperature during the anodic oxidation of aluminum plates. Iron atoms penetrated into pores with diameters of less than 160 nm, and were stabilized by forming γ-Fe, whereas α-Fe was produced as a flat plane covering the pores. For porous alumina substrates with pore sizes larger than 200 nm, the deposited iron films contained many defects and the resulting α-Fe had smaller hyperfine magnetic fields. In addition, only a very small amount of γ-Fe was obtained. It was demonstrated that the composition and structure of an iron film can be affected by the surface morphology of the porous alumina substrate on which the film is grown.

  8. Microwave fast sintering of submicrometer alumina

    Directory of Open Access Journals (Sweden)

    Romualdo Rodrigues Menezes

    2010-09-01

    Full Text Available Commercially available alumina powder with high-purity submicrometer particle size and narrow particle size distribution was fully densified by a microwave hybrid fast firing technique. The alumina compacts were surrounded by susceptor material, which helped the heating of the samples, and sintered in a microwave oven at a frequency of 2.45 GHz and a power level of 1.8 kW. The sintered samples reached densities of 99% in sintering cycles of 30 to 40 minutes, a much shorter time than conventional sintering processes. The sintered samples showed uniform microstructures with powder particle size/average grain size rations higher than 1:2.

  9. Nanomechanical humidity detection through porous alumina cantilevers

    Directory of Open Access Journals (Sweden)

    Olga Boytsova

    2015-06-01

    Full Text Available We present here the behavior of the resonance frequency of porous anodic alumina cantilever arrays during water vapor adsorption and emphasize their possible use in the micromechanical sensing of humidity levels at least in the range of 10–22%. The sensitivity of porous anodic aluminium oxide cantilevers (Δf/Δm and the humidity sensitivity equal about 56 Hz/pg and about 100 Hz/%, respectively. The approach presented here for the design of anodic alumina cantilever arrays by the combination of anodic oxidation and photolithography enables easy control over porosity, surface area, geometric and mechanical characteristics of the cantilever arrays for micromechanical sensing.

  10. Tribological properties of nanoscale alumina-zirconia composites

    NARCIS (Netherlands)

    Kerkwijk, B.; Winnubst, A.J.A.; Verweij, H.; Mulder, E.J.; Metselaar, H.S.C.; Schipper, D.J.

    1999-01-01

    The tribological properties of zirconia (Y-TZP), alumina and their composites, alumina dispersed in zirconia (ADZ) and zirconia-toughened alumina (ZTA), were investigated. These ceramics are made by colloidal processing methods such that well-defined, homogeneous microstructures with submicron grain

  11. A Novel Processing Route for Ni-doped Alumina Composites

    Institute of Scientific and Technical Information of China (English)

    JING Mao-xiang; SHEN Xiang-qian; ZHOU Jian-xin; LI Dong-hong; LI Wang-xing

    2006-01-01

    Alumina-based composites containing 0-15wt% Ni metallic phase were produced by hot press-sintering Ni-coated alumina powders. The Ni-coated alumina powders were prepared by the aqueous heterogeneous precipitation of alumina micro-powders and nickel sulfate salt followed by reduction process. The microstructural features and dispersion of Ni phase in Ni-coated alumina powders and the subsequent alumina-Ni cermets were investigated using scanning electron microscope (SEM), X-ray diffractometer (XRD), and transmission electron microscope (TEM). The relative density of the hot press-sintered composites was measured with the Archimedes' method while the fracture strength and the fracture toughness were defined with the three-point bending method and the micro-indentation fracture method. In the formation of alumina-Ni cermets from sintered Ni-coated alumina powders, Ni phase to some extent limits the densification rate and stifles the coarsening and growing process of alumina grains. The Ni phase is found to be located at the interfaces and the triple-joint junctions of alumina grains which results into alteration of the fracture mode of alumina and its increased fracture strength and fracture toughness if compared with monolithic alumina.

  12. The COHERENT Experiment at the Spallation Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, Steven Ray [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

    2015-09-30

    The COHERENT collaboration's primary objective is to measure coherent elastic neutrino- nucleus scattering (CEvNS) using the unique, high-quality source of tens-of-MeV neutrinos provided by the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL). In spite of its large cross section, the CEvNS process has never been observed, due to tiny energies of the resulting nuclear recoils which are out of reach for standard neutrino detectors. The measurement of CEvNS has now become feasible, thanks to the development of ultra-sensitive technology for rare decay and weakly-interacting massive particle (dark matter) searches. The CEvNS cross section is cleanly predicted in the standard model; hence its measurement provides a standard model test. It is relevant for supernova physics and supernova-neutrino detection, and enables validation of dark-matter detector background and detector-response models. In the long term, precision measurement of CEvNS will address questions of nuclear structure. COHERENT will deploy multiple detector technologies in a phased approach: a 14-kg CsI[Na] scintillating crystal, 15 kg of p-type point-contact germanium detectors, and 100 kg of liquid xenon in a two-phase time projection chamber. Following an extensive background measurement campaign, a location in the SNS basement has proven to be neutron-quiet and suitable for deployment of the COHERENT detector suite. The simultaneous deployment of the three COHERENT detector subsystems will test the N=2 dependence of the cross section and ensure an unambiguous discovery of CEvNS. This document describes concisely the COHERENT physics motivations, sensitivity and plans for measurements at the SNS to be accomplished on a four-year timescale.

  13. 5 MW pulsed spallation neutron source, Preconceptual design study

    Energy Technology Data Exchange (ETDEWEB)

    1994-06-01

    This report describes a self-consistent base line design for a 5 MW Pulsed Spallation Neutron Source (PSNS). It is intended to establish feasibility of design and as a basis for further expanded and detailed studies. It may also serve as a basis for establishing project cost (30% accuracy) in order to intercompare competing designs for a PSNS not only on the basis of technical feasibility and technical merit but also on the basis of projected total cost. The accelerator design considered here is based on the objective of a pulsed neutron source obtained by means of a pulsed proton beam with average beam power of 5 MW, in {approx} 1 {mu}sec pulses, operating at a repetition rate of 60 Hz. Two target stations are incorporated in the basic facility: one for operation at 10 Hz for long-wavelength instruments, and one operating at 50 Hz for instruments utilizing thermal neutrons. The design approach for the proton accelerator is to use a low energy linear accelerator (at 0.6 GeV), operating at 60 Hz, in tandem with two fast cycling booster synchrotrons (at 3.6 GeV), operating at 30 Hz. It is assumed here that considerations of cost and overall system reliability may favor the present design approach over the alternative approach pursued elsewhere, whereby use is made of a high energy linear accelerator in conjunction with a dc accumulation ring. With the knowledge that this alternative design is under active development, it was deliberately decided to favor here the low energy linac-fast cycling booster approach. Clearly, the present design, as developed here, must be carried to the full conceptual design stage in order to facilitate a meaningful technology and cost comparison with alternative designs.

  14. Thermal Conductivity of Alumina-Toughened Zirconia Composites

    Science.gov (United States)

    Bansal, Narottam P.; Zhu, Dong-Ming

    2003-01-01

    10-mol% yttria-stabilized zirconia (10YSZ)-alumina composites containing 0 to 30 mol% alumina were fabricated by hot pressing at 1500 C in vacuum. Thermal conductivity of the composites, determined at various temperatures using a steady-state laser heat flux technique, increased with increase in alumina content. Composites containing 0, 5, and 10-mol% alumina did not show any change in thermal conductivity with temperature. However, those containing 20 and 30-mol% alumina showed a decrease in thermal conductivity with increase in temperature. The measured values of thermal conductivity were in good agreement with those calculated from simple rule of mixtures.

  15. LOW TEMPERATURE SINTERING OF ALUMINA BIOCERAMIC UNDER NORMAL PRESSURE

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Superfine alumina powder with high purity (mean particle size is less than 0. 35μm) were used as main starting material for sintering alumina ceramic. A multiple additive MgO-ZrO2 (Y2O3) was homogeneously added into the batch by the chemical coprecipitation method. Sintering of alumina bioceramic at low tempera ture (<1600C) was achieved resulting in a dense and high strength alumina ceramic with the bending strength up to 382 MPa and an improved fracture toughness. Mechanism that the multiple additives promote the sintering of alumina ceramic is discussed on the base of XRD and SEM analysis.

  16. Selective metallization of alumina by laser

    NARCIS (Netherlands)

    Shrivastva, P.B.; Boose, C.A.; Kolster, B.H.; Harteveld, C.; Meinders, B.

    1991-01-01

    Nickel has been selectively deposited on an alumina substrate without any pretreatment from a flow of a nickel acetate solution using the focused beam of an excimer laser. Nickel spots as well as nickel lines were drawn and subsequently plated with an electroless Ni-B coating. Excellent adhesion of

  17. Stabilization of Self-Assembled Alumina Mesophases

    NARCIS (Netherlands)

    Perez, Lidia Lopez; Perdriau, Sebastien; ten Brink, Gert; Kooi, Bart J.; Heeres, Hero Jan; Melian-Cabrera, Ignacio

    2013-01-01

    An efficient route to stabilize alumina mesophases derived from evaporation-induced self-assembly is reported after investigating various aspects in-depth: influence of the solvent (EtOH, s-BuOH, and t-BuOH) on the textural and structural properties of the mesophases based on aluminum tri-sec-butoxi

  18. Alumina ceramics prepared with new pore-forming agents

    Directory of Open Access Journals (Sweden)

    Zuzana Živcová

    2008-06-01

    Full Text Available Porous ceramics have a wide range of applications at all length scales, ranging from fi ltration membranes and catalyst supports to biomaterials (scaffolds for bone ingrowths and thermally or acoustically insulating bulk materials or coating layers. Organic pore-forming agents (PFAs of biological origin can be used to control porosity, pore size and pore shape. This work concerns the characterization and testing of several less common pore-forming agents (lycopodium, coffee, fl our and semolina, poppy seed, which are of potential interest from the viewpoint of size, shape or availability. The performance of these new PFAs is compared to that of starch, which has become a rather popular PFA for ceramics during the last decade. The PFAs investigated in this work are in the size range from 5 μm (rice starch to approximately 1 mm (poppy seed, all with more or less isometric shape. The burnout behavior of PFAs is studied by thermal analysis, i.e. thermogravimetry and differential thermal analysis. For the preparation of porous alumina ceramics from alumina suspensions containing PFAs traditional slip casting (into plaster molds and starch consolidation casting (using metal molds are used in this work. The resulting microstructures are investigated using optical microscopy, combined with image analysis, as well as other methods (Archimedes method of double-weighing in water, mercury intrusion porosimetry.

  19. Dielectric Performance of High Purity HTCC Alumina at High Temperatures - A Comparison Study with Other Polycrystalline Alumina

    Science.gov (United States)

    Chen, Liang-Yu

    2012-01-01

    A very high purity (99.99+) high temperature co-fired ceramic (HTCC) alumina has recently become commercially available. The raw material of this HTCC alumina is very different from conventional HTCC alumina, and more importantly there is no glass additive in this co-fired material. Previously, selected HTCC and LTCC (low temperature co-fired ceramic) alumina materials were evaluated at high temperatures as dielectric and compared to a regularly sintered 96 polycrystalline alumina (96 Al2O3), where 96 alumina was used as the benchmark. A prototype packaging system based on regular 96 alumina with Au thick-film metallization successfully facilitated long term testing of high temperature silicon carbide (SiC) electronic devices for over 10,000 hours at 500C. In order to evaluate this new HTCC alumina for possible high temperature packaging applications, the dielectric properties of this HTCC alumina substrate were measured and compared with those of 96 alumina and a LTCC alumina from room temperature to 550C at frequencies of 120 Hz, 1 KHz, 10 KHz, 100 KHz, and 1 MHz. A parallel-plate capacitive device with dielectric of the HTCC alumina and precious metal electrodes were used for measurements of the dielectric constant and dielectric loss of the co-fired alumina material in the temperature and frequency ranges. The capacitance and AC parallel conductance of the capacitive device were directly measured by an AC impedance meter, and the dielectric constant and parallel AC conductivity of the dielectric were calculated from the capacitance and conductance measurement results. The temperature and frequency dependent dielectric constant, AC conductivity, and dissipation factor of the HTCC alumina substrate are presented and compared to those of 96 alumina. Other technical advantages of this new co-fired material for possible high packaging applications are also discussed.

  20. MECHANICAL BEHAVIOUR OF ALUMINA-ZIRCONIA COMPOSITE BY SLURRY METHOD

    Directory of Open Access Journals (Sweden)

    JYOTI PRAKASH

    2011-02-01

    Full Text Available Alumina has got some excellent properties like chemical inertness, thermal and mechanical strength against hazardous environment. Alumina is a good ceramic material which is being used for structuralapplications. To enhance the toughness and strength of the body some Zirconia is also used with it. The use of Zirconia in alumina is known as toughening of alumina. One difficulty arises, when alumina and alumina toughened composite are sintered , because the low sinterability of Alumina-Zirconia forced the compact to give very low density body. To overcome this problem alumina and alumina composites are made from slurry method which gives nearly theoretical density. The combined effect of alumina and Zirconia on the phase transformation and microstructure development of heat-treated Alumina-Zirconia composites has been studied. Slurry is prepared by adding water, dispersant, binder and anti-foaming agent. In the present study, Sintering schedule is optimized and kept constant for all samples. After sintering, mechanical behaviour of the composite has been studied.

  1. Surface modification of alumina nanoparticles with silane coupling agents

    Energy Technology Data Exchange (ETDEWEB)

    Prado, Luis A.S.A.; Sriyai, Montira; Ghislandi, Marcos; Schulte, Karl [Technische Universitaet Hamburg-Harburg, Hamburg (Germany). Inst. fuer Kunststoffe und Verbundwerkstoffe (M-11); Barros-Timmons, Ana [University of Aveiro (Portugal). Dept. of Chemistry. Centro de Investigacao em Materiais Ceramicos e Compositos (CICECO)

    2010-07-01

    In the present paper we describe the surface modification of alumina nanoparticles using epoxy-containing alkoxysilanes (silane coupling agents, SCA). The materials were characterized using infrared spectroscopy and solid-state nuclear magnetic resonance. Whereas, neat alumina nanoparticles could be expectedly modified with the afore mentioned SCA, as evidenced by {sup 13}C CPMAS NMR, the presence of arylsulphonates at the surface of alumina caused the ringopening polymerization of the epoxide. This polymerization reaction facilitated the surface modification of alumina by the SCA. X-ray powder diffraction and {sup 27}Al MAS NMR clearly demonstrated that in spite of the SCA polymerization, there were neither structural changes nor phase transitions in the alumina after the surface modification. The surface modification decreased the thermal stability of alumina, in comparison to pristine alumina nanoparticles. (author)

  2. Study of alumina-trichite reinforcement of a nickel-based matric by means of powder metallurgy

    Science.gov (United States)

    Walder, A.; Hivert, A.

    1982-01-01

    Research was conducted on reinforcing nickel based matrices with alumina trichites by using powder metallurgy. Alumina trichites previously coated with nickel are magnetically aligned. The felt obtained is then sintered under a light pressure at a temperature just below the melting point of nickel. The halogenated atmosphere technique makes it possible to incorporate a large number of additive elements such as chromium, titanium, zirconium, tantalum, niobium, aluminum, etc. It does not appear that going from laboratory scale to a semi-industrial scale in production would create any major problems.

  3. Quantitative measurement of the film interface strength by laser spallation technique

    Institute of Scientific and Technical Information of China (English)

    周明; 张永康; 蔡兰

    2001-01-01

    A novel laser spallation technique for quantitatively measuring the film interface strength is presented. Through the analysis of the physical procedure of the film spallation, a mathematical model is established based on the multiple reflections and transmissions of the stress waves within film, and a formula for calculating the interface strength and the strain rate is obtained. Using this method the interface strength of Cr stainless steel/TiN, Al/EPOXY and Fe/EPOXY are measured. A new method of wave-shape analysis is developed to judge the film spallation intuitionally, and to determine the spall moment, spall depth and spall strength directly. The film interface strength has been measured using single laser shock.

  4. Application of Origen2.1 in the decay photon spectrum calculation of spallation products

    CERN Document Server

    Hong, Shuang; Xu, Hu-Shan; Meng, Hai-Yan; Zhang, Lu; Liu, Zhao-Qing; Gao, Yu-Cui; Chen, Kang

    2016-01-01

    Origen2.1 is a widely used computer code for calculating the burnup, decay, and processing of radioactive materials. However, the nuclide library of Origen2.1 is used for existing reactors like pressurized water reactor, to calculate the photon spectrum released by the decay of spallation products, we have made specific libraries for the ADS tungsten spallation target, based on the results given by a Monte Carlo code: FLUKA. All the data used to make the Origen2.1 libraries is obtained from Nuclear structure & decay Data (NuDat2.6). The accumulated activity of spallation products and the contribution of nuclides to photon emission are given in this paper.

  5. Degradation of alumina and zirconia toughened alumina (ZTA) hip prostheses tested under microseparation conditions in a shock device

    CERN Document Server

    Uribe, Juliana; Gremillard, Laurent; Reynard, Bruno

    2013-01-01

    This paper considers the degradation of alumina and zirconia toughened alumina vs. alumina for hip implants. The materials are as assumed to be load bearing surfaces subjected to shocks in wet conditions. The load is a peak of force; 9 kN was applied over 15 ms at 2 Hz for 800,000 cycles. The volumetric wear and roughness are lower for ZTA than for alumina. The long ZTA ageing did not seem to have a direct influence on the roughness. The ageing increased the wear volumes of ZTA and it was found to have a higher wear resistance compared to alumina.

  6. Graphene coated with alumina and its utilization as a thermal conductivity enhancer for alumina sphere/thermoplastic polyurethane composite

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki Tae; Dao, Trung Dung [Department of Chemistry, Energy Harvest-Storage Research Center, University of Ulsan, Ulsan 680-749 (Korea, Republic of); Jeong, Han Mo, E-mail: hmjeong@mail.ulsan.ac.kr [Department of Chemistry, Energy Harvest-Storage Research Center, University of Ulsan, Ulsan 680-749 (Korea, Republic of); Anjanapura, Raghu V. [Center for Emerging Technologies, Jain Global Campus, Jain University, Jakkasandra, Ramanagara 562-112 (India); Aminabhavi, Tejraj M. [Soniya College of Pharmacy, S. R. Nagar, Dharwad 580-002 (India)

    2015-03-01

    Graphene was oxidized with H{sub 2}O{sub 2} to introduce additional anchoring sites for effective alumina coating on graphene by the sol–gel method. The X-ray photoelectron spectroscopy studies showed that the oxygen-containing groups such as hydroxyl group useful for coating were introduced by the oxidation. The transmission electron microscopy images and thermogravimetric analysis data demonstrated that the additional anchoring sites enhanced the efficiency of the alumina coating. A small amount of alumina-coated graphene synergistically improved the thermal conductivity of the alumina sphere/thermoplastic polyurethane (TPU) composite without any increase in the electrical conductivity, because the electrical conductivity of graphene effectively decreased by the alumina coating. Moreover, the synergistic effect of a small amount of graphene was enhanced by the alumina coating, and the stiffening of the alumina sphere/TPU composite due to the added graphene was alleviated by the alumina coating. - Highlights: • Oxidation of graphene with H{sub 2}O{sub 2} introduced anchoring sites for alumina coating. • The anchoring sites improved the efficiency of alumina coating on graphene. • The alumina-coated graphene synergistically enhanced the thermal conductivity.

  7. Application of Origen2.1 in the decay photon spectrum calculation of spallation products

    OpenAIRE

    Hong, Shuang; Yang, Yong-Wei; Xu, Hu-Shan; Meng, Hai-Yan; Zhang, Lu; Liu, Zhao-Qing; Gao, Yu-Cui; Chen, Kang

    2016-01-01

    Origen2.1 is a widely used computer code for calculating the burnup, decay, and processing of radioactive materials. However, the nuclide library of Origen2.1 is used for existing reactors like pressurized water reactor, to calculate the photon spectrum released by the decay of spallation products, we have made specific libraries for the ADS tungsten spallation target, based on the results given by a Monte Carlo code: FLUKA. All the data used to make the Origen2.1 libraries is obtained from N...

  8. The test beamline of the European Spallation Source - Instrumentation development and wavelength frame multiplication

    DEFF Research Database (Denmark)

    Woracek, R.; Hofmann, T.; Bulat, M.

    2016-01-01

    The European Spallation Source (ESS), scheduled to start operation in 2020, is aiming to deliver the most intense neutron beams for experimental research of any facility worldwide. Its long pulse time structure implies significant differences for instrumentation compared to other spallation sources...... which, in contrast, are all providing short neutron pulses. In order to enable the development of methods and technology adapted to this novel type of source well in advance of the first instruments being constructed at ESS, a test beamline (TBL) was designed and built at the BER II research reactor...

  9. Present status of spallation target development. JAERI/KEK Joint Project

    Energy Technology Data Exchange (ETDEWEB)

    Hino, R.; Kaminaga, M.; Haga, K. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment] [and others

    2001-03-01

    The Japan Atomic Energy Research Institute (JAERI) and the High Energy Accelerator Research Organization (KEK) are promoting a plan to construct a neutron scattering facility under the JAERI/KEK Joint Project. Design and R and D works are being carried out vigorously for realizing the mercury target system consisting of the mercury target, moderators and reflectors working as a spallation neutron source, as well as a remote handling system for exchanging such components which will be highly irradiated. This report introduces an outline of the present status of design and development activities on the spallation target system. (author)

  10. Rheological Properties of Aqueous Nanometric Alumina Suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Chuanping Li

    2004-12-19

    Colloidal processing is an effective and reliable approach in the fabrication of the advanced ceramic products. Successful colloidal processing of fine ceramic powders requires accurate control of the rheological properties. The accurate control relies on the understanding the influences of various colloidal parameters on the rheological properties. Almost all research done on the rheology paid less attention to the interactions of particle and solvent. However, the interactions of the particles are usually built up through the media in which the particles are suspended. Therefore, interactions of the particle with the media, the adsorbed layers on the particle surface, and chemical and physical properties of media themselves must influence the rheology of the suspension, especially for the dense suspensions containing nanosized particles. Relatively little research work has been reported in this area. This thesis addresses the rheological properties of nanometric alumina aqueous suspensions, and paying more attention to the interactions between particle and solvent, which in turn influence the particle-particle interactions. Dense nanometric alumina aqueous suspensions with low viscosity were achieved by environmentally-benign fructose additives. The rheology of nanometric alumina aqueous suspensions and its variation with the particle volume fraction and concentration of fructose were explored by rheometry. The adsorptions of solute (fructose) and solvent (water) on the nanometric alumina particle surfaces were measured and analyzed by TG/DSC, TOC, and NMR techniques. The mobility of water molecules in the suspensions and its variation with particle volume fractions and fructose additive were determined by the {sup 17}O NMR relaxation method. The interactions between the nanometric alumina particles in water and fructose solutions were investigated by AFM. The results indicated that a large number of water layers were physically bound on the particles

  11. Rheological Properties of Aqueous Nanometric Alumina Suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chuanping [Iowa State Univ., Ames, IA (United States)

    2004-01-01

    Colloidal processing is an effective and reliable approach in the fabrication of the advanced ceramic products. Successful colloidal processing of fine ceramic powders requires accurate control of the rheological properties. The accurate control relies on the understanding the influences of various colloidal parameters on the rheological properties. Almost all research done on the rheology paid less attention to the interactions of particle and solvent. However, the interactions of the particles are usually built up through the media in which the particles are suspended. Therefore, interactions of the particle with the media, the adsorbed layers on the particle surface, and chemical and physical properties of media themselves must influence the rheology of the suspension, especially for the dense suspensions containing nanosized particles. Relatively little research work has been reported in this area. This thesis addresses the rheological properties of nanometric alumina aqueous suspensions, and paying more attention to the interactions between particle and solvent, which in turn influence the particle-particle interactions. Dense nanometric alumina aqueous suspensions with low viscosity were achieved by environmentally-benign fructose additives. The rheology of nanometric alumina aqueous suspensions and its variation with the particle volume fraction and concentration of fructose were explored by rheometry. The adsorptions of solute (fructose) and solvent (water) on the nanometric alumina particle surfaces were measured and analyzed by TG/DSC, TOC, and NMR techniques. The mobility of water molecules in the suspensions and its variation with particle volume fractions and fructose additive were determined by the 17O NMR relaxation method. The interactions between the nanometric alumina particles in water and fructose solutions were investigated by AFM. The results indicated that a large number of water layers were physically bound on the particles

  12. The spallation in reverse kinematics: what for a coincidence measurement?; La spallation en cinematique inverse: pourquoi faire une mesure en coincidence?

    Energy Technology Data Exchange (ETDEWEB)

    Ducret, J.E

    2006-07-15

    The Spaladin installation has been designed to study spallation reactions in reverse kinematics. Furthermore, the heavy and light fragments are detected by coincidence which allows us to get an instantaneous picture of the reaction at a level of accuracy better than that obtained through inclusive measurement. The first part is dedicated to the theoretical description of the different mechanisms involved in the spallation reactions. In the second part we describe the Spaladin installation and report some results on the reaction: Fe{sup 56} + p at an energy of 1 GeV/nucleon. In the third part we expose the performance of the installation through its simulation with the Geant-IV model. We present a study about the sensitivity of the Spaladin installation to theoretical predictions. The fourth part is dedicated to the future experiments that will be performed with the Spaladin installation. (A.C.)

  13. Dissertation: Precompound Emission of Energetic Light Fragments in Spallation Reactions

    Energy Technology Data Exchange (ETDEWEB)

    Kerby, Leslie Marie [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-08-04

    Emission of light fragments (LF) from nuclear reactions is an open question. Different reaction mechanisms contribute to their production; the relative roles of each, and how they change with incident energy, mass number of the target, and the type and emission energy of the fragments is not completely understood. None of the available models are able to accurately predict emission of LF from arbitrary reactions. However, the ability to describe production of LF (especially at energies ≳ 30 MeV) from many reactions is important for different applications, such as cosmic-ray-induced Single Event Upsets (SEUs), radiation protection, and cancer therapy with proton and heavy-ion beams, to name just a few. The Cascade-Exciton Model (CEM) version 03.03 and the Los Alamos version of the Quark-Gluon String Model (LAQGSM) version 03.03 event generators in Monte Carlo N-Particle Transport Code version 6 (MCNP6) describe quite well the spectra of fragments with sizes up to ⁴He across a broad range of target masses and incident energies (up to ~ 5 GeV for CEM and up to ~ 1 TeV/A for LAQGSM). However, they do not predict the high energy tails of LF spectra heavier than ⁴He well. Most LF with energies above several tens of MeV are emitted during the precompound stage of a reaction. The current versions of the CEM and LAQGSM event generators do not account for precompound emission of LF larger than ⁴He. The aim of our work is to extend the precompound model in them to include such processes, leading to an increase of predictive power of LF-production in MCNP6. This entails upgrading the Modified Exciton Model currently used at the preequilibrium stage in CEM and LAQGSM. It also includes expansion and examination of the coalescence and Fermi break-up models used in the precompound stages of spallation reactions within CEM and LAQGSM. Extending our models to include emission of fragments heavier than ⁴He at the precompound stage has indeed provided results that have much

  14. Preparation and Testing of Corrosion and Spallation-Resistant Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Hurley, John

    2015-11-01

    with the Rene 80. One-inch-diameter buttons were machined from each of the bonded blocks and sent to Siemens for standard oxidation, spallation, and corrosion testing, which should be complete in the spring of 2016.

  15. Nanoparticles in alumina: Microscopy and Theory

    Science.gov (United States)

    Idrobo, Juan C.; Halabica, Andrej; Rashkeev, Sergey; Glazoff, Michael V.; Boatner, Lynn A.; Haglund, Richard F.; Pennycook, Stephen. J.; Pantelides, Sokrates T.

    2007-03-01

    Transition-metal nanoparticles formed by ion implantation in alumina can be used to modify the optical properties of naturally oxidized and anodized aluminum. Here, we report atomic-resolution Z-contrast images using a scanning transmission electron microscope (STEM) of CoFe and other metal nanoparticles in alumina. We also report electron energy loss spectra (EELS) and relate them to visual appearance and optical properties. Finally, we report first-principles density- functional calculations of nucleation mechanisms for these nanoparticles. This research was sponsored by the Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, U.S. Department of Energy, under contract DE-AC05- 00OR22725 with Oak Ridge National Laboratory, managed and operated by UT-Battelle, by NSF grant No. DMR-0513048, and by Alcoa Inc.

  16. Silica containing highly porous alumina ceramic

    Science.gov (United States)

    Svinka, R.; Svinka, V.; Zake, I.

    2011-04-01

    Porous alumina ceramic were produced by slip casting of aqueous alumina slurry with added small amount of metallic aluminium powder. Pores form in result of chemical reaction of aluminum with water by hydrogen gas evolution reaction and solidification of suspension. Porosity of such materials sintered at a temperature of 1600 - 1750°C varies from 60 to 90%. Pore size distribution and mechanical strength of these materials depend largely on the grain size of used raw materials. The major part of pores in the materials produced without additive of silica are larger than 10 ±m, but with 5 - 10 wt.% additive of silica in the raw mix pore size decreases considerably. The sintering shrinkage decreases to 2.5%. Coefficient of thermal expansion equally decreases from 8.9-10-6 K-1 to 7.1 10-6 K-1 and classification temperature increases to 1600°C, while deformation at high temperature decreases considerably.

  17. Impact of AD995 alumina rods

    Energy Technology Data Exchange (ETDEWEB)

    Chhabildas, L.C.; Furnish, M.D.; Reinhart, W.D. [Sandia National Labs., Albuquerque, NM (United States); Grady, D.E. [Applied Research Associates, Inc., Albuquerque, NM (United States)

    1997-10-01

    Gas guns and velocity interferometric techniques have been used to determine the loading behavior of an AD995 alumina rod 19 mm in diameter by 75 mm and 150 mm long, respectively. Graded-density materials were used to impact both bare and sleeved alumina rods while the velocity interferometer was used to monitor the axial-velocity of the free end of the rods. Results of these experiments demonstrate that (1) a time-dependent stress pulse generated during impact allows an efficient transition from the initial uniaxial strain loading to a uniaxial stress state as the stress pulse propagates through the rod, and (2) the intermediate loading rates obtained in this configuration lie between split Hopkinson bar and shock-loading techniques.

  18. Ultraviolet photoluminescence of porous anodic alumina films

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Photoluminescence (PL) properties of porous anodic alumina (PAA) films prepared by using electrochemical anodization technique in a mixed solution of oxalic and sulfuric acid have been investigated. The PAA films have an intensive ultraviolet PL emission around 350 nm, of which a possible PL mechanism has been proposed. It was found that the incorporated oxalic ions, which could transform into PL centers and exist in the PAA films, are responsible for this ultraviolet PL emission.

  19. Tribology of alumina-graphite composites

    Science.gov (United States)

    Yu, Chih-Yuan

    Alumina-graphite composites, which combine high wear resistance and self-lubricity, are a potential and promising candidate for advanced tribological applications. The processing, mechanical properties and tribology of alumina-graphite composites are discussed. Full density is difficult to achieve by a pressureless sintering route. Porosity of the composites increases with graphite content which causes the strength, modulus of elasticity, and hardness of the composites to decrease. The increased porosity does cause the fracture toughness to slightly increases. Tribology of alumina-graphite composites was studied with a pin-on-disk tribometer with emphasis on the following aspects: the graphite content in both pin and disk, the graphite flake size and the orientation of the graphite flakes. Scan electronic microscopy (SEM) and X-ray diffraction are utilized to examine and characterize the wear debris and the worn surface. Results confirmed that it is necessary to optimize the structure and the supply of lubricant to improve the tribological behavior and that the arrangements of sliding couples also affect the tribology of self-lubricated ceramic composites. Continuous measurements of the friction coefficients were collected at high frequency in an attempt to correlate the tribology of alumina-graphite composites to vibrations introduced by friction. While these measurements indicate that the time frequency behavior of tribology is an important area of study, conclusions regarding the frequency response of different sliding couples could not be definitively stated. Finally, a new concept connecting instantaneous wear coefficient and instantaneous contact stress is proposed for prediction of wear behavior of brittle materials.

  20. Comparison of Different INC Physical Models of MCNPX to Compute Spallation Neutronics of LBE Target

    Science.gov (United States)

    Feghhi, Seyed Amir Hossein; Gholamzadeh, Zohreh; Tenreiro, Claudio; Alipoor, Zahra

    2015-04-01

    Spallation particles can utilize in different fields such as neutron scattering studies, external source for burning spent fuel as well as running subcritical reactors. Different computational particle transport codes are widely used to model spallation process into the heavy targets. Among these codes, MCNPX 2.6.0 comprises various intra nuclear cascade models for spallation calculations. Impact of different intra nuclear cascade models on calculation of neutronic parameters of LBE target has been evaluated in this work. Escaped neutron yield, energy deposition and residual nuclei production in the spallation target has been calculated using the physical models. A comparison between the computational and experimental has been carried out to validate the computational data. The simulation data showed there is a good conformity between the obtained data from Bertini/Drenser and Isabel/Drenser. The data achieved by Bertini/Abla and Isabel/Abla models are close to each other for the studied parameters as well. Among the studied models, CEM showed more discrepancies with experimental and other computational data. According to the obtained data, INCL4/Drenser, INCL4/Abla and Isabel/Drenser models can meet more agreements with experimental data.

  1. Study on target spallation reaction cross sections induced by high energy neutrons and heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Takashi [Tohoku Univ., Sendai (Japan). Cyclotron and Radioisotope Center

    1996-03-01

    The target spallation reaction cross sections of neutrons and heavy ions which have not been observed are determined in this paper. The object of this work is to make clear the differences between the spallation reaction cross section of neutron and that of proton by comparing the obtained value of neutron with the known value of proton. To this end, the quasi monochromatic neutron field of 20{approx}50 MeV was developed in 4 cyclotrons, INS, CYRIC, TIARA and RIKEN. The nuclear spallation reaction cross sections of C, Al and Bi were measured in the above field and the distribution of nuclear spallation reaction products in Cu determined by C ion beam of HIMAC. {sup 12}C(n,2n){sup 11}C reaction cross section shows the maximum value of about 20 mb at near 40{approx}50 MeV and then the value gradually decreased to 10 mb. The cross sections of {sup 209}Bi(n,Xn) are shown. The distribution of {sup 61}Cu is lower at the entrance and higher in the depth. (S.Y.)

  2. Migration of radionuclides in a gas cooled solid state spallation target

    DEFF Research Database (Denmark)

    Jørgensen, Thomas; Severin, Gregory; Jensen, Mikael

    2015-01-01

    The current design of the ESS (European Spallation Source) program proposes a rotating solid tungsten target cooled by helium gas and a pulsed beam of protons. For safety reasons any design has to address whether or not the induced radionuclidic isotopes in the target migrate. In this paper we ha...

  3. Decay heat calculations for a 500 kW W–Ta spallation target

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Quanzhi, E-mail: qzhyu@iphy.ac.cn [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Lu, Youlian; Hu, Zhiliang; Zhou, Bin [Dongguan Campus, Institute of High Energy Physics, Chinese Academy of Sciences, Dongguan 523800 (China); Dongguan Neutron Science Center, Dongguan 523800 (China); Yin, Wen; Liang, Tianjiao [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

    2015-05-15

    The China Spallation Neutron Source (CSNS) is a short-pulsed neutron scattering facility. The beam power is designed to be 100 kW in Phase I, with the capability of upgrading to 500 kW. Tantalum (Ta)-cladded tungsten (W) was chosen as the spallation target due to its high neutron yield. Ta claddings can solve the problem of the corrosiveness of W plates, although they produce high decay heat after intense irradiation. This paper presents the decay heat distributions and evolutions for the future upgraded 500 kW W–Ta spallation target. The calculations are performed using the MCNPX2.5 Monte Carlo code and the CINDER’90 activation code. The decay heat distributions show that for the W plates, decay heat is mainly produced via the spallation reaction process, whereas for the Ta claddings, it is mainly produced via the neutron capture process. An effective method of reducing the decay heat in the W–Ta target is also presented and discussed.

  4. Porous Aluminas: The bio template method for the synthesis of stable high surface area aluminas; Aluminas porosas: El metodo de bio-replica para la sintesis de aluminas estables de alta superficie especifica

    Energy Technology Data Exchange (ETDEWEB)

    Benitez Guerrero, M.; Perez Maqueda, L.; Pena Castro, P.; Pascual Cosp, J.

    2013-07-01

    Development of porous alumina has been the objective of numerous studies in recent decades, due to the intrinsic properties of aluminium oxide, such as high melting point, low thermal conductivity, chemical inertness and corrosion resistance which, in addition to a high surface area and permeability, make aluminas being used for many different industrial and technical applications. The crystallographic and textural stability of alumina acquires significant importance in those processes involving high temperatures; however, most of the synthesis methods yield metastable oxides of little interest in high-temperature processes due to the transformation to alpha phase, with the consequent reduction in surface area. The present article reviews diverse procedures for obtaining porous alumina with high specific surface area, including methods and strategies for preparing high surface alpha-alumina. Within this framework, the paper analyzes the results obtained through bio replica of lignocellulose materials. This technology allows preparing aluminas with the complex structural hierarchy of the lignocellulose templates. (Author)

  5. Synthesis and characterization of single-crystalline alumina nanowires

    Institute of Scientific and Technical Information of China (English)

    ZHAO Qing; XU Xiang-yu; ZHANG Hong-zhou; CHEN Yao-feng; XU Jun; YU Da-peng

    2005-01-01

    Alumina nanowires were synthesized on large-area silicon substrate via simple thermal evaporation method of heating a mixture of aluminum and alumina powders without using any catalyst or template. The phase structure and the surface morphology of the as-grown sample were analyzed by X-ray diffractometry(XRD) and scanning electron microscopy (SEM), respectively. The chemical composition and the microstructure of the as-grown alumina nanowires were characterized using transmission electron microscope(TEM). The nanowires are usually straight and the single crystalline has average diameter of 40 nm and length of 3 - 5 μm. The growth direction is along the [002] direction. Well aligned alumina nanowire arrays were observed on the surface of many large particles. The catalyst-free growth of the alumina nanowires was explained under the framework of a vapor-solid(VS)growth mechanism. This as-synthesized alumina nanowires could find potential applications in the fabrication of nanodevices.

  6. VERITAS: a high-flux neutron reflectometer with vertical sample geometry for a long pulse spallation source

    Science.gov (United States)

    Mattauch, S.; Ioffe, A.; Lott, D.; Menelle, A.; Ott, F.; Medic, Z.

    2016-04-01

    An instrument concept of a reflectometer with a vertical sample geometry fitted to the long pulse structure of a spallation source, called “VERITAS” at the ESS, is presented. It focuses on designing a reflectometer with high intensity at the lowest possible background following the users' demand to investigate thin layers or interfacial areas in the sub-nanometer length scale. The high intensity approach of the vertical reflectometer fits very well to the long pulse structure of the ESS. Its main goal is to deliver as much usable intensity as possible at the sample position and be able to access a reflectivity range of 8 orders of magnitude and more. The concept assures that the reflectivity measurements can be performed in its best way to maximize the flux delivered to the sample. The reflectometer is optimized for studies of (magnetic) layers having thicknesses down to 5Å and a surface area of 1x1cm2. With reflectivity measurements the depth-resolved, laterally averaged chemical and magnetic profile can be investigated. By using polarised neutrons, additional vector information on the in-plane magnetic correlations (off-specular scattering at the pm length scale, GISANS at the nm length scale) can be studied. The full polarisation analysis could be used for soft matter samples to correct for incoherent scattering which is presently limiting neutron reflectivity studies to a reflectivity range on the order of 10-6.

  7. Free-standing alumina nanobottles and nanotubes pre-integrated into nanoporous alumina membranes

    Science.gov (United States)

    Fang, Jinghua; Levchenko, Igor; (Ken Ostrikov, Kostya

    2014-08-01

    A novel interfacial structure consisting of long (up to 5 μm), thin (about 300 nm), highly-ordered, free-standing, highly-reproducible aluminum oxide nanobottles and long tubular nanocapsules attached to a rigid, thin (less than 1 μm) nanoporous anodic alumina membrane is fabricated by simple, fast, catalyst-free, environmentally friendly voltage-pulse anodization. A growth mechanism is proposed based on the formation of straight channels in alumina membrane by anodization, followed by neck formation due to a sophisticated voltage control during the process. This process can be used for the fabrication of alumina nanocontainers with highly controllable geometrical size and volume, vitally important for various applications such as material and energy storage, targeted drug and diagnostic agent delivery, controlled drug and active agent release, gene and biomolecule reservoirs, micro-biologically protected platforms, nano-bioreactors, tissue engineering and hydrogen storage.

  8. Influence of TAC on Dispersion of Aqueous Nano Alumina Suspension

    Institute of Scientific and Technical Information of China (English)

    ZHAO Wei; YANG De-an; SONG Jian-jing; YANG Zi; LIANG Chong; XU Ming-xia; XU Ting-xian

    2004-01-01

    The stability of aqueous nano alumina powder suspensions with and without dispersant tri-ammonium citrate (TAC) was investigated by measuring zeta potential at different pH values. The isoelectric point (IEP) of alumina powder shifts towards more acidic pH range by adding TAC dispersant. The results illustrate that adsorption of TAC on alumina powder surface existed in the aqueous suspension, which leads to a high stability of the suspension.

  9. Corrosion of Refractory Alumina-Graphite and Alumina-Graphite-Zirconia in Slag Containing Titania

    Institute of Scientific and Technical Information of China (English)

    XU Yuan; LIU Qing-cai; BAI Chen-guang; CHEN Deng-fu; Joseph W Newkirk

    2004-01-01

    The corrosion of refractory alumina-graphite and alumina-graphite-zirconia in the slag containing titania was studied by immersion tests (quasi-static and dynamic tests). Combining direct observation with microscopic investigations, a mechanism for corrosion was proposed based on the oxidation of graphite and the dissolution of refractory components. During the corrosion process, there are some special phenomena and laws that can be explained by the relation between the corrosion rate and the TiO2 mass percent, the rotational refractory velocity and the morphology of the deteriorated layer.

  10. Aqueous combustion synthesis and characterization of zirconia-alumina nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Kishan, J.; Mangam, Venu; Reddy, B.S.B.; Das, Siddhartha [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Kharagpur, West Bengal 721302 (India); Das, Karabi, E-mail: karabi@metal.iitkgp.ernet.i [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Kharagpur, West Bengal 721302 (India)

    2010-02-04

    The zirconia-alumina nanocomposite powders with 3-48 mol% of alumina are prepared by aqueous combustion synthesis technique using stoichiometric amounts of aluminium nitrate, zirconyl nitrate and glycine. The nanopowders are compacted uniaxially and sintered at 1000 {sup o}C temperature in a muffle furnace. Thermodynamic modeling of the combustion reaction shows that, as the alumina content increases, the amount of gases produced increases with a decrease in the adiabatic flame temperature. The green and sintered densities of cold press composite powders decrease with an increase in the mol% of alumina.

  11. Rheology of Alumina-Based Graphite-Containing Castables

    Institute of Scientific and Technical Information of China (English)

    YE Fangbao; M. Rigaud; LIU Xinhong; ZHONG Xiangchong

    2005-01-01

    In this work, the rheological behavior of ultra-low cement alumina-based castables with addition of flake graphite and extruded graphite pellets has been investigated by using IBB rheometer. Emphasis has been laid on the influence of the type and amount of carbon addition on rheological properties of the alumina-based castables and the results are compared with corresponding alumina castable samples without any carbon addition. It is found that alumina-based castables with extruded graphite pellets have good rheological behavior and flowability with lower water demand ( < 6. 3% )and no segregation during the shearing of castable.

  12. Modelling the initial stage of porous alumina growth during anodization

    Science.gov (United States)

    Aryslanova, E. M.; Alfimov, A. V.; Chivilikhin, S. A.

    2013-05-01

    Artificially on the surface of aluminum there may be build a thick layer of Al2O3, which has a porous structure. In this paper we present a model of growth of porous alumina in the initial stage of anodizing, identifying dependencies anodizing parameters on the rate of growth of the film and the distance between the pores and as a result of the created model equations were found for changes in the disturbance of alumina for the initial stage of anodizing aluminum oxide porous border aluminum-alumina and alumina-electrolyte, with the influence of surface diffusion of aluminum oxide.

  13. Mechanisms of spallation of electron beam physical vapor deposited thermal barrier coatings with and without platinum aluminide bond coat ridges

    Energy Technology Data Exchange (ETDEWEB)

    Vaidyanathan, K.; Gell, M. [Connecticut Univ., Storrs, CT (United States). Dept. of Metallurgy; Jordan, E. [Dept. Mechanical Engineering, University of Connecticut, CT-06269, Storrs (United States)

    2000-11-01

    Grain boundary ridges, that form on the surface of platinum aluminide [(Ni,Pt)Al] bond coats prior to the deposition of the yttria stabilized zirconia ceramic layer by the electron beam physical vapor deposition (EB-PVD) process, were shown to be the sites for spallation damage initiation in (Ni,Pt)Al/EB-PVD thermal barrier coatings. When these ridges are removed prior to deposition of the ceramic layer, a 3 x life improvement is achieved. This study compares the spallation mechanisms in specimens with and without bond coat ridges, in order to explain the improvement in spallation life. (orig.)

  14. Study of particle transport in a high power spallation target for an accelerator-driven transmutation system

    Energy Technology Data Exchange (ETDEWEB)

    Shetty, Nikhil Vittal

    2013-01-31

    AGATE is a project envisaged to demonstrate the feasibility of transmutation in a gas (helium) cooled accelerator-driven system using solid spallation target. Development of the spallation target module and assessing its safety aspects are studied in this work. According to the AGATE concept parameters, 600 MeV protons are delivered on to the segmented tungsten spallation target. The Monte Carlo toolkit Geant4 has been used in the simulation of particle transport. Binary cascade is used to simulate intra-nuclear cascades, along with the G4NDL neutron data library for low energy neutrons (<20 MeV).

  15. Damping Behavior of Alumina Epoxy Nano-Composites

    Science.gov (United States)

    Katiyar, Priyanka; Kumar, Anand

    2016-05-01

    Polymer nano composites, consisting of a polymer matrix with nanoparticle filler, have been predicted to be one of the most beneficial applications of nanotechnology. Addition of nano particulates to a polymer matrix enhances its performance by capitalizing on the nature and properties of the nano-scale fillers. The damping behavior of composites with nano structured phases is significantly different from that of micro structured materials. Viscoelastic homopolymer exhibit a high material damping response over a relatively narrow range of temperature and frequencies. In many practical situations, a polymeric structure is required to possess better strength and stiffness properties together with a reasonable damping behavior. Viscoelastic polymers show higher loss factor beyond the glassy region which comes with a significant drop in the specific modulus. Addition of nano alumina particles to epoxy leads to improved strength and stiffness properties with an increase in glass transition temperature while retaining its damping capability. Experimental investigations are carried out on composite beam specimen fabricated with different compositions of alumina nano particles in epoxy to evaluate loss factor, tan δ. Impact damping method is used for time response analysis. A single point Laser is used to record the transverse displacement of a point on the composite beam specimen. The experimental results are compared with theoretical estimation of loss factor using Voigt estimation. The effect of inter phase is included in theoretical estimation of loss factor. The result reveals that the study of interface properties is very important in deriving the overall loss factor of the composite since interface occupies a significant volume fraction in the composite.

  16. Damping Behavior of Alumina Epoxy Nano-Composites

    Science.gov (United States)

    Katiyar, Priyanka; Kumar, Anand

    2016-10-01

    Polymer nano composites, consisting of a polymer matrix with nanoparticle filler, have been predicted to be one of the most beneficial applications of nanotechnology. Addition of nano particulates to a polymer matrix enhances its performance by capitalizing on the nature and properties of the nano-scale fillers. The damping behavior of composites with nano structured phases is significantly different from that of micro structured materials. Viscoelastic homopolymer exhibit a high material damping response over a relatively narrow range of temperature and frequencies. In many practical situations, a polymeric structure is required to possess better strength and stiffness properties together with a reasonable damping behavior. Viscoelastic polymers show higher loss factor beyond the glassy region which comes with a significant drop in the specific modulus. Addition of nano alumina particles to epoxy leads to improved strength and stiffness properties with an increase in glass transition temperature while retaining its damping capability. Experimental investigations are carried out on composite beam specimen fabricated with different compositions of alumina nano particles in epoxy to evaluate loss factor, tan δ. Impact damping method is used for time response analysis. A single point Laser is used to record the transverse displacement of a point on the composite beam specimen. The experimental results are compared with theoretical estimation of loss factor using Voigt estimation. The effect of inter phase is included in theoretical estimation of loss factor. The result reveals that the study of interface properties is very important in deriving the overall loss factor of the composite since interface occupies a significant volume fraction in the composite.

  17. Experimental measurement of surface temperatures during flame-jet induced thermal spallation

    Science.gov (United States)

    Wilkinson, M. A.; Tester, J. W.

    1993-01-01

    Thermal spallation is a method whereby the surface of a rock is rapidly heated causing small (100 1000 μm) flakes or spalls, to form. When applied to drilling, a supersonic, high temperature (2600 K) gas jet is directed at the rock to provide the heat source and sweep away the spalls. Previous studies of thermal spallation drilling indicate that penetration rates of up to 30 m/hr (100 ft/hr), approximately ten times greater than commonly obtained using conventional rotary mechanical methods, can be achieved in competent, non-fractured hard rock such as granite. A total direct operating cost for drilling in granite using a flame-jet spallation drill was estimated by Browning (1981) to be approximately 9/m in 1991 (about 3/ft) compared to “trouble-free” well drilling costs for conventional rotary methods in similar rock to depths of 3 to 7 km (10000 to 21000 ft) of 300 to 900/m (100 to 300/ft) (Tester and Herzog, 1990, 1992). The Browning estimates for spallation drilling are obviously optimistic in that they don't include capital costs for the rig and associated hardware. However, the substantially higher penetration rates, significantly reduced wear of downhole components, and the high efficiency of rock communition in comparison to rotary methods suggest that substantial cost reductions could be possible in deep drilling applications. For example, in the construction of hot dry rock geothermal power plants where rotary mechanical methods are used for well drilling to depths of (4 to 5 km), about half of the initial capital cost would be required for well drilling alone (Tester and Herzog, 1992). The current study has focused on gaining a better understanding of both the rock failure mechanism that occurs during thermal spallation and the heat transfer from the gas jet to the rock surface. Rock mechanics modeling leads to an expression for the surface temperature during spallation as a function of rock physical properties and the incident heat flux. Surface

  18. Segregation phenomena at growing alumina/alloy interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Peggy Y.

    2005-03-30

    The chemistry and structure at the scale/alloy interface are important factors governing scale adhesion. The chemical changes can occur from segregation of impurities in the alloy, such as sulphur and carbon, or alloying elements such as chromium, aluminium and reactive elements. This paper reviews studies of the changes of interfacial composition with oxidation time for Al{sub 2}O{sub 3} formed on several model alumina-forming alloys, and tries to relate that to the interfacial strength. Results show that sulphur segregation to oxide/metal interfaces can indeed occur, but the type and amount of segregants at the interface depend on the alloy composition and the interface structure. Co-segregation of impurities with alloying elements can also occur, resulting in multi-layer segregants at the interface. Sulphur-containing interfaces are indeed weaker, but the major role of sulphur is to enhance interfacial void formation. Reactive elements in the alloy not only gather sulfur but also exert an additional positive effect on scale adhesion.

  19. Nanotube Arrays in Porous Anodic Alumina Membranes

    Institute of Scientific and Technical Information of China (English)

    Liang LI; Naoto KOSHIZAKI; Guanghai LI

    2008-01-01

    This review summarizes the various techniques developed for fabricating nanotube arrays in porous anodic alumina membranes (AAMs). After a brief introduction to the fabrication process of AAMs, taking carbons, metals, semiconductors, organics, biomoleculars, and heterojunctions as typical examples, attention will be focused on the recently established methods to fabricate nanotubes in AAM, including electrochemical deposition, surface sol-gel, modified chemical vapor deposition, atomic layer deposition, and layer-by-layer growth. Every method is demonstrated by one or two reported results. Finally, this review is concluded with some perspectives on the research directions and focuses on the AAM-based nanotubes fields.

  20. Anisotropic shrinkage characteristics of tape cast alumina

    Science.gov (United States)

    Patwardhan, Jaideep Suresh

    Dimensional control during sintering is a major issue in ceramics processing to avoid high post-sintering costs associated with machining of the fired ceramic part to desired tolerances and dimensions. Ceramic forming processes such as tape casting, injection molding, and extrusion involve shear of anisotropic particles resulting in preferential alignment of the particles in the green body. This preferential alignment causes directionality in mechanical, electrical, optical, and magnetic properties and most importantly warpage or distortion during sintering. A large effort has been devoted to synthesizing ceramic green bodies with minimal density gradients and uniform packing and modeling the sintering behavior evolution but little effort has been devoted to characterizing orientation of particles and the effect of preferential alignment on sintering shrinkage anisotropy. A systematic study was initiated to study the effect of processing variables such as shear rate, solids loading, temperature, and binder content on aqueous tape cast alumina. Three different alumina systems: A16-SG, Baikowski RC-UFX DBM and RC-LS DBM were investigated. Aqueous tapes of high solids loading alumina (56 vol. %) were tape cast at various speeds and thicknesses and assuming plane Couette flow a shear rate regime of 21--270 s-1 was investigated. Higher shear rates and high solids loading resulted in higher in-plane anisotropy whereas the anisotropy in the thickness direction was higher for low solids loading systems. The anisotropy was found to be fairly constant above a certain critical shear rate (˜100 s-1) irrespective of the temperature and the solids loading and this correlated with the viscosity-shear rate relationship of the cast slips. The higher shrinkage anisotropy in the thickness direction for the low solids loading systems (35 and 45 vol. %) was attributed to the higher amount of organics in the slip required to sustain the suitable viscosity for tape casting and

  1. NMR Revealed Activated Alumina-Water Interaction

    Institute of Scientific and Technical Information of China (English)

    ZHOU Rui; ZHOU Yan; HU Kai; JI Zhen-ping; CHENG Gong-zhen

    2005-01-01

    Three different spin-lattice relaxation times (T1) of water were obtained in activated alumina-water slurry system, which indicate that there exist three states of water: bound water, pore water and bulk water. The chemical shift (δH) decreases as the amount of water added to the system increases due to the differences in contribution of these three states of water in the samples. The δH value for adsorbed water decreases nearly linearly and T1 increases with elevating temperature, which result from the decrease in the content of bound water by the increase in thermal motion.

  2. Spray freeze granulation of submicron alumina and its sintering behavior via spark plasma sintering

    Directory of Open Access Journals (Sweden)

    Liu Wei

    2015-01-01

    Full Text Available Spray freeze granulation is an improved method based on spray granulation, solving many limitations of spray granulation. In this work, spray freeze granulation of submicron alumina is performed to explore the possibility of industrial-scale production of dense alumina via spark plasma sintering. Powder pretreatment such as sedimentation and the selection of granules with the appropriate size are employed for the maximum use of the high qualified as-prepared granules and granule sliding, which would provide a guidance for the industrial-scale production. Debound granules were densified via SPS and the corresponding sintering behaviors such as the recorded shrinkage and shrinkage rate were discussed. The comparison of sintering behaviors between granulated and as-received powder are conducted to identify the role of spray freeze granulation in sinterability for dense alumina. The Vickers hardness (Hv and the fracture toughness (KIC of the freeze granulated body are higher than the corresponding properties of the as-received body due to the more homogenous microstructure with little agglomeration in the particle packing after freeze granulation.

  3. Issues in nanocomposite ceramic engineering: focus on processing and properties of alumina-based composites.

    Science.gov (United States)

    Palmero, Paola; Kern, Frank; Sommer, Frank; Lombardi, Mariangela; Gadow, Rainer; Montanaro, Laura

    2014-12-30

    Ceramic nanocomposites, containing at least one phase in the nanometric dimension, have received special interest in recent years. They have, in fact, demonstrated increased performance, reliability and lifetime with respect to monolithic ceramics. However, a successful approach to the production of tailored composite nanostructures requires the development of innovative concepts at each step of manufacturing, from the synthesis of composite nanopowders, to their processing and sintering.This review aims to deepen understanding of some of the critical issues associated with the manufacturing of nanocomposite ceramics, focusing on alumina-based composite systems. Two case studies are presented and briefly discussed. The former illustrates the benefits, in terms of sintered microstructure and related mechanical properties, resulting from the application of an engineering approach to a laboratory-scale protocol for the elaboration of nanocomposites in the system alumina-ZrO2-YAG (yttrium aluminium garnet). The latter illustrates the manufacturing of alumina-based composites for large-scale applications such as cutting tools, carried out by an injection molding process. The need for an engineering approach to be applied in all processing steps is demonstrated also in this second case study, where a tailored manufacturing process is required to obtain the desired results.

  4. Characterization of the alumina film with cerium doped on the iron-aluminide diffusion coating

    Energy Technology Data Exchange (ETDEWEB)

    Zhan, Q., E-mail: zhanqin1983@163.com; Yang, H.G.; Zhao, W.W.; Yuan, X.M.; Hu, Y.

    2013-11-15

    An iron-aluminide layer with a thin alumina film on the top as a composite tritium permeation barrier (TPB) coating was characterized under different oxidation conditions. The TPB coating was prepared initially on a China Low Activation Ferritic-Martensitic (CLAM) steel by a pack cementation aluminizing process and then an alumina film was formed on the surface of this iron-aluminide diffusion layer by an oxidizing process. To modify the properties of the FeAl/Al{sub 2}O{sub 3} composite TPB coatings, the rare earth element (cerium) was introduced as a dopant while oxidizing. Characterization showed that a continuous oxide scale with a thickness of about 300–400 nm was formed on the FeAl diffusion layer. The film was mainly composed of Al{sub 2}O{sub 3} doped with a little CeO{sub 2}. In addition, the concentration of α-Al{sub 2}O{sub 3} increased with elevated temperature while oxidizing. The phase transformation behavior of alumina scale on the surface of an iron-aluminide layer was studied in this paper.

  5. Chemical modification/grafting of mesoporous alumina with polydimethylsiloxane (PDMS)

    NARCIS (Netherlands)

    Pinheiro de Melo, A.F.; Nijmeijer, A.; Sripathi, V.G.P.; Winnubst, A.J.A.

    2015-01-01

    A method for polydimethylsiloxane grafting of alumina powders is described which involves chemical modification of the surface of mesoporous (5 nm) γ-alumina flakes with a linker (3-aminopropyltriethoxysilane: APTES), either by a solution phase (SPD) or a vapour phase (VPD) reaction, followed by PDM

  6. Development of Reproducing Alumina-Magnesia-Carbon Bricks

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The reproducing alumina-magnesia-carbon bricks were prepared with the dumped bricks as starting materials. The bulk density, apparent porosity, crushing strength, modolus of rupture and slag resistance of the specimen were analyzed. The results show that the used refractories can be reused and recycled by the right method. The reproducing alumina-magnesia-carbon bricks with better abilities were prepared.

  7. Textural stability of titania–alumina composite membranes

    NARCIS (Netherlands)

    Kumar, Krishnankutty-Nair P.; Keizer, Klaas; Burggraaf, Anthonie J.

    1993-01-01

    Textural evolution (porosity reduction, pore and crystallite growth) in titania–alumina composite membranes has been studied using thermal analysis, X-ray diffraction, field emission scanning electron microscopy and N2 physisorption techniques. The presence of alumina in the membranes improved the t

  8. 21 CFR 73.1010 - Alumina (dried aluminum hydroxide).

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Alumina (dried aluminum hydroxide). 73.1010 Section 73.1010 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1010 Alumina (dried...

  9. Dynamic compressive and tensile strengths of spark plasma sintered alumina

    Science.gov (United States)

    Girlitsky, I.; Zaretsky, E.; Kalabukhov, S.; Dariel, M. P.; Frage, N.

    2014-06-01

    Fully dense submicron grain size alumina samples were manufactured from alumina nano-powder using Spark Plasma Sintering and tested in two kinds of VISAR-instrumented planar impact tests. In the first kind, samples were loaded by 1-mm tungsten impactors, accelerated to a velocity of about 1 km/s. These tests were aimed at studying the Hugoniot elastic limit (HEL) of Spark Plasma Sintering (SPS)-processed alumina and the decay, with propagation distance, of the elastic precursor wave. In the tests of the second kind, alumina samples of 3-mm thickness were loaded by 1-mm copper impactors accelerated to 100-1000 m/s. These tests were aimed at studying the dynamic tensile (spall) strength of the alumina specimens. The tensile fracture of the un-alloyed alumina shows a monotonic decline of the spall strength with the amplitude of the loading stress pulse. Analysis of the decay of the elastic precursor wave allowed determining the rate of the irreversible (inelastic) strains in the SPS-processed alumina at the initial stages of the shock-induced inelastic deformation and to clarify the mechanisms responsible for the deformation. The 1-% addition of Cr2O3 decreases the HEL of the SPS-processed alumina by 5-% and its spall strength by 50% but barely affects its static properties.

  10. 40 CFR 721.10120 - Siloxane modified alumina nanoparticles (generic).

    Science.gov (United States)

    2010-07-01

    ... nanoparticles (generic). 721.10120 Section 721.10120 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.10120 Siloxane modified alumina nanoparticles (generic). (a) Chemical... as siloxane modified alumina nanoparticles (PMN P-05-687) is subject to reporting under this...

  11. Thermal Shock Behaviour of Alumina-Iron Composites

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Thermal shock behaviour was investigated for two morphologically different composites comprising an alumina matrix and 20 vol. pct Fe particles for a wide range of quenching temperature differences (△T=100~800°C) and compared to a monolithic alumina. The retained strength and critical quenching temperature difference, △Tc, of the two composites were a significant improvement over the values for the respective monolithic alumina. Crack lengths and densities were shown to be greater for the alumina than for the two composites at all quenching temperature differences. The thermal shock resistance parameters for monolithic alumina and the two composites were calculated according to their mechanical and physical properties. The calculated results agree well with the experimental one and indicate possible explanations for the differences in thermal shock behaviour.

  12. Comparison of deep desulfurization methods in alumina production process

    Institute of Scientific and Technical Information of China (English)

    刘战伟; 李旺兴; 马文会; 尹中林; 武国宝

    2015-01-01

    Several methods of deep desulfurization in alumina production process were studied, and the costs of these methods were compared. It is found that most of the S2− in sodium aluminate solution can be removed by adding sodium nitrate or hydrogen peroxide in digestion process, and in this way the effect of S2− on alumina product quality is eliminated. However, the removal efficiency of2-23SOin sodium aluminate solution is very low by this method. Both S2− and2-23SO in sodium aluminate solution can be removed completely by wet oxidation method in digestion process. The cost of desulfurization by wet oxidation is lower than by adding sodium nitrate or hydrogen peroxide. The results of this research reveal that wet oxidation is an economical and feasible method for the removal of sulfur in alumina production process to improve alumina quality, and provide valuable guidelines for alumina production by high-sulfur bauxite.

  13. Morphology and transmittance of porous alumina on glass substrate

    Energy Technology Data Exchange (ETDEWEB)

    Guo Peitao, E-mail: guopeitao@hotmail.com [Wuhan University of Technology. Wuhan (China); Xia Zhilin [Wuhan University of Technology. Wuhan (China); Key Laboratory of Low Dimensional Materials and Application Technology, Xiangtan University, Ministry of Education, Xiangtan (China); Xue Yiyu [Wuhan University of Technology. Wuhan (China); Huang Caihua [China Three Gorges University, Yichang (China); Zhao Lixin [Wuhan University of Technology. Wuhan (China)

    2011-02-01

    The porous optical film has higher threshold of laser-induced damage than densified films, for the study of mechanism of laser-induced damage of porous optical film with ordered pore structure. Porous anodic alumina (PAA) film with high transmittance on glass substrate has been prepared. Aluminum film was deposited on glass substrate by means of resistance and electron beam heat (EBH) evaporation. Porous alumina was prepared in oxalic acid solution under different anodizing conditions. At normal incidence, the optical transmittance spectrum over 300-1000 nm spectra region was obtained by spectrophotometer. SEM was introduced to analysis the morphology of the porous alumina film. The pore aperture increased with the increase of anodizing voltage, which resulted in a rapid decrease of the pore concentration and the optical thickness of porous alumina film. Damage morphology of porous alumina film is found to be typically defects initiated, and the defect is the pore presented on the film.

  14. Thermal Conductivity of Alumina-reinforced Zirconia Composites

    Science.gov (United States)

    Bansal, Narottam P.

    2005-01-01

    10-mol% yttria-stabilized zirconia (10SZ) - alumina composites containing 0-30 mol% alumina were fabricated by hot pressing at 1500 C in vacuum. Thermal conductivity was determined at various temperatures using a steady-state laser heat flux technique. Thermal conductivity of the composites increased with increase in alumina content. Composites containing 0, 5, and 10-mol% alumina did not show any change in thermal conductivity with temperature. However, those containing 20 and 30-mol% alumina showed a decrease in thermal conductivity with increase in temperature. The measured values of thermal conductivity were in good agreement with those calculated from the Maxwell-Eucken model where one phase is uniformly dispersed within a second major continuous phase.

  15. Experimental and numerical investigation of liquid-metal free-surface flows in spallation targets

    Energy Technology Data Exchange (ETDEWEB)

    Batta, A., E-mail: batta@kit.edu [Karlsruhe Institute of Technology, Germany Hermann-von-Helmholtz-PLATZ 1, 76344 Eggenstein-Leopoldshafen (Germany); Class, A.G.; Litfin, K.; Wetzel, Th. [Karlsruhe Institute of Technology, Germany Hermann-von-Helmholtz-PLATZ 1, 76344 Eggenstein-Leopoldshafen (Germany); Moreau, V.; Massidda, L. [CRS4 Centre for Advanced Studies, Research and Development in Sardinia, Polaris, Edificio 1, 09010 Pula, CA (Italy); Thomas, S.; Lakehal, D. [ASCOMP GmbH Zurich, Zurich (Switzerland); Angeli, D.; Losi, G. [DIEF – Department of Engineering “Enzo Ferrari”, University of Modena and Reggio Emilia, via Vignolese 905, 41125 Modena (Italy); Mooney, K.G. [University of Massachusetts Amherst, Department of Mechanical and Industrial Engineering, Amherst (United States); Van Tichelen, K. [SCK-CEN, Belgian Nuclear Research Centre, Boeretang 200, 2400 Mol (Belgium)

    2015-08-15

    Highlights: • Experimental study of free surface for lead bismuth eutectic target. • Numerical investigation of free surface of a liquid metal target. • Advanced free surface modelling. - Abstract: Accelerator Driven Systems (ADS) are extensively investigated for the transmutation of high-level nuclear waste within many worldwide research programs. The first advanced design of an ADS system is currently developed in SCK• CEN, Mol, Belgium: the Multi-purpose hYbrid Research Reactor for High-tech Applications (MYRRHA). Many European research programs support the design of MYRRHA. In the framework of the Euratom project ‘Thermal Hydraulics of Innovative nuclear Systems (THINS)’ a liquid-metal free-surface experiment is performed at the Karlsruhe Liquid Metal Laboratory (KALLA) of Karlsruhe Institute of Technology (KIT). The experiment investigates a full-scale model of the concentric free-surface spallation target of MYRRHA using Lead Bismuth Eutectic (LBE) as coolant. In parallel, numerical free surface models are developed and tested which are reviewed in the article. A volume-of-fluid method, a moving mesh model, a free surface model combining the Level-Set method with Large-Eddy Simulation model and a smoothed-particle hydrodynamics approach are investigated. Verification of the tested models is based on the experimental results obtained within the THINS project and on previous water experiments performed at the University Catholic de Louvain (UCL) within the Euratom project ‘EUROpean Research Programme for the TRANSmutation of High Level Nuclear Waste in Accelerator Driven System (EUROTRANS)’. The design of the target enables a high fluid velocity and a stable surface at the beam entry. The purpose of this paper is to present an overview of both experimental and numerical results obtained for free surface target characterization. Without entering in technical details, the status, the major achievements and lessons for the future with respect to

  16. Cost Optimisation of an Instrument Suite at an Accelerator-Driven Spallation Source

    CERN Document Server

    Bentley, P M

    2016-01-01

    This artcile presents an optimisation of performance and cost of neutron scattering instrumentation at the European Spallation Source. This is done by trading detailed cost functions against beam transmission functions in a multi-dimensional, yet simple, parameter space. On the one hand, the neutron guide cost increases as a power of the desired beam divergence, and inversely with the minimum wavelength, due to the supermirror coating needed. On the other hand, the more neutrons are transported to the instrument the greater are the shielding costs to deal with the gamma rays that result from the eventual absorption of the neutrons. There are additional factors in that many of the parameters defining the neutron guide geometry are continuous variables, and the straightness of the guide increases the transmission of high energy spallation products, which affect the specifications of particularly heavy hardware, such as heavy shutters and additional shielding, beam stops etc. Over the suite of 16 instruments, a ...

  17. An apparatus for studying spallation neutrons in the Aberdeen Tunnel laboratory

    CERN Document Server

    Blyth, S C; Chen, X C; Chu, M C; Hahn, R L; Ho, T H; Hsiung, Y B; Hu, B Z; Kwan, K K; Kwok, M W; Kwok, T; Lau, Y P; Lee, K P; Leung, J K C; Leung, K Y; Lin, G L; Lin, Y C; Luk, K B; Luk, W H; Ngai, H Y; Ngan, S Y; Pun, C S J; Shih, K; Tam, Y H; Tsang, R H M; Wang, C H; Wong, C M; Wong, H L; Wong, H H C; Wong, K K; Yeh, M

    2013-01-01

    In this paper, we describe the design, construction and performance of an apparatus installed in the Aberdeen Tunnel laboratory in Hong Kong for studying spallation neutrons induced by cosmic-ray muons under a vertical rock overburden of 611 meter water equivalent (m.w.e.). The apparatus comprises of six horizontal layers of plastic-scintillator hodoscopes for determining the direction and position of the incident cosmic-ray muons. Sandwiched between the hodoscope planes is a neutron detector filled with 650 kg of liquid scintillator doped with about 0.06% of Gadolinium by weight for improving the e?ciency of detecting the spallation neutrons. Performance of the apparatus is also presented.

  18. Challenges and design solutions of the liquid hydrogen circuit at the European Spallation Source

    Science.gov (United States)

    Gallimore, S.; Nilsson, P.; Sabbagh, P.; Takibayev, A.; Weisend, J. G., II; Beßler, Y.; Klaus, M.

    2014-01-01

    The European Spallation Source (ESS), Lund, Sweden will be a 5MW long-pulse neutron spallation research facility and will enable new opportunities for researchers in the fields of life sciences, energy, environmental technology, cultural heritage and fundamental physics. Neutrons are produced by accelerating a high-energy proton beam into a rotating helium-cooled tungsten target. These neutrons pass through moderators to reduce their energy to an appropriate range (cooling medium. There are several technical challenges to overcome in the design of a robust system that will operate under such conditions, not least the 20 kW of deposited heat. These challenges and the associated design solutions will be detailed in this paper.

  19. THERMAL HYDRAULIC ANALYSIS OF A LIQUID-METAL-COOLED NEUTRON SPALLATION TARGET

    Energy Technology Data Exchange (ETDEWEB)

    W. GREGORY; R. MARTIN; T. VALACHOVIC

    2000-07-01

    We have carried out numerical simulations of the thermal hydraulic behavior of a neutron spallation target where liquid metal lead-bismuth serves as both coolant and as a neutron spallation source. The target is one of three designs provided by the Institute of Physics and Power Engineering (IPPE) in Russia. This type of target is proposed for Accelerator-driven Transmutation of Waste (ATW) to eliminate plutonium from hazardous fission products. The thermal hydraulic behavior was simulated by use of a commercial CFD computer code called CFX. Maximum temperatures in the diaphragm window and in the liquid lead were determined. In addition the total pressure drop through the target was predicted. The results of the CFX analysis were close to those results predicted by IPPE in their preliminary analysis.

  20. Synthesis of neutron-rich transuranic nuclei in fissile spallation targets

    CERN Document Server

    Mishustin, Igor; Pshenichnov, Igor; Greiner, Walter

    2014-01-01

    A possibility of synthesizing neutron-reach super-heavy elements in spallation targets of Accelerator Driven Systems (ADS) is considered. A dedicated software called Nuclide Composition Dynamics (NuCoD) was developed to model the evolution of isotope composition in the targets during a long-time irradiation by intense proton and deuteron beams. Simulation results show that transuranic elements up to Bk-249 can be produced in multiple neutron capture reactions in macroscopic quantities. However, the neutron flux achievable in a spallation target is still insufficient to overcome the so-called fermium gap. Further optimization of the target design, in particular, by including moderating material and covering it by a reflector will turn ADS into an alternative source of transuranic elements in addition to nuclear fission reactors.

  1. Systematic neutron guide misalignment for an accelerator-driven spallation neutron source

    Science.gov (United States)

    Zendler, C.; Bentley, P. M.

    2016-08-01

    The European Spallation Source (ESS) is a long pulse spallation neutron source that is currently under construction in Lund, Sweden. A considerable fraction of the 22 planned instruments extend as far as 75-150 m from the source. In such long beam lines, misalignment between neutron guide segments can decrease the neutron transmission significantly. In addition to a random misalignment from installation tolerances, the ground on which ESS is built can be expected to sink with time, and thus shift the neutron guide segments further away from the ideal alignment axis in a systematic way. These systematic errors are correlated to the ground structure, position of buildings and shielding installation. Since the largest deformation is expected close to the target, even short instruments might be noticeably affected. In this study, the effect of this systematic misalignment on short and long ESS beam lines is analyzed, and a possible mitigation by overillumination of subsequent guide sections investigated.

  2. Studies Performed in Preparation for the Spallation Neutron Source Accumulator Ring Commissioning

    CERN Document Server

    Cousineau, Sarah M; Henderson, Stuart; Holmes, Jeffrey Alan; Plum, Michael

    2005-01-01

    The Spallation Neutron Source accumulator ring will compress 1.5?1014, 1 GeV protons from a 1 ms bunch train to a single 695 ns proton bunch for use in neutron spallation. Due to the high beam power, unprecedented control of beam loss will be required in order to control radiation and allow for hands-on maintenance in most areas of the ring. A number of detailed investigations have been performed to understand the primary sources of beam loss and to predict and mitigate problems associated with radiation hot spots in the ring. The ORBIT particle tracking code is used to perform realistic simulations of the beam accumulation in the ring, including detailed modeling of the injection system, transport through the measured magnet fields including higher order multipoles, and beam loss and collimation. In this paper we present the results of a number of studies performed in preparation for the 2006 commissioning of the accumulator ring.

  3. Properties of Transition Metal Doped Alumina

    Science.gov (United States)

    Nykwest, Erik; Limmer, Krista; Brennan, Ray; Blair, Victoria; Ramprasad, Rampi

    Crystallographic texture can have profound effects on the properties of a material. One method of texturing is through the application of an external magnetic field during processing. While this method works with highly magnetic systems, doping is required to couple non-magnetic systems with the external field. Experiments have shown that low concentrations of rare earth (RE) dopants in alumina powders have enabled this kind of texturing. The magnetic properties of RE elements are directly related to their f orbital, which can have as many as 7 unpaired electrons. Since d-block elements can have as many as 5 unpaired electrons the effects of substitutional doping of 3d transition metals (TM) for Al in alpha (stable) and theta (metastable) alumina on the local structure and magnetic properties, in addition to the energetic cost, have been calculated by performing first-principles calculations based on density functional theory. This study has led to the development of general guidelines for the magnetic moment distribution at and around the dopant atom, and the dependence of this distribution on the dopant atom type and its coordination environment. It is anticipated that these findings can aid in the selection of suitable dopants help to guide parallel experimental efforts. This project was supported in part by an internship at the Army Research Laboratory, administered by the Oak Ridge Institute for Science and Education, along with a grant of computer time from the DoD High Performance Computing Modernization Program.

  4. Modified-starch Consolidation of Alumina Ceramics

    Institute of Scientific and Technical Information of China (English)

    JU Chenhui; WANG Yanmin; YE Jiandong; HUANG Yun

    2008-01-01

    The alumina ceramics with the homogeneous microstructure and the higher density were fabricated via the modified-starch consolidation process by 1.0 wt%of a modified starch as a consolidator/binder.The swelling behavior of the modified oxidized tapioca starch was analyzed by optical microscope,and two other corn starches(common corn starch and high amylose COrn starch)were also analyzed for comparison.The modified starch used as a binder for the consolidation swelled at about 55℃.began to gelatinize at 65℃ and then was completely gelatinized at 75℃.But the corn starches could not be completely gelatinized even at 80℃for 1 h.The high-strength green bodies(10.6 MPa)with the complex shapes were produced.The green bodies were sintered without any binder burnout procedure at 1700℃and a relative density of 95.3% was obtained for the sintered bodies,which is similar to that of the sintered sample formed by conventional slip casting.In addition,the effect of temperature on the apparent viscosity of the starch/alumina slurry in the process was investigated,and the corresponding mechanism for the starch consolidation was discussed.

  5. Parsing abnormal grain growth in specialty aluminas

    Science.gov (United States)

    Lawrence, Abigail Kremer

    Grain growth in alumina is strongly affected by the impurities present in the material. Certain impurity elements are known to have characteristic effects on abnormal grain growth in alumina. Specialty alumina powders contain multiple impurity species including MgO, CaO, SiO2, and Na 2O. In this work, sintered samples made from alumina powders containing various amounts of the impurities in question were characterized by their grain size and aspect ratio distributions. Multiple quantitative methods were used to characterize and classify samples with varying microstructures. The grain size distributions were used to partition the grain size population into subpopulations depending on the observed deviation from normal behavior. Using both grain size and aspect ratio a new visual representation for a microstructure was introduced called a morphology frequency map that gives a fingerprint for the material. The number of subpopulations within a sample and the shape of the distribution on the morphology map provided the basis for a classification scheme for different types of microstructures. Also using the two parameters a series of five metrics were calculated that describe the character of the abnormal grains in the sample, these were called abnormal character values. The abnormal character values describe the fraction of grains that are considered abnormal, the average magnitude of abnormality (including both grain size and aspect ratio), the average size, and variance in size. The final metric is the correlation between grain size and aspect ratio for the entire population of grains. The abnormal character values give a sense of how different from "normal" the sample is, given the assumption that a normal sample has a lognormal distribution of grain size and a Gaussian distribution of aspect ratios. In the second part of the work the quantified measures of abnormality were correlated with processing parameters such as composition and heat treatment conditions. A

  6. Determination of spallation residues in thin target: toward an hybrid reactor lead target simulation

    Energy Technology Data Exchange (ETDEWEB)

    Audouin, L.; Tassan-Got, L.; Bernas, M.; Rejmund, F.; Stephan, C.; Taieb, J. [Paris-11 Univ., 91- Orsay (France). Inst. de Physique Nucleaire; Enqvist, T.; Armbruster, P.; Ricciardi, M.V.; Schmidt, K.H. [GSI, Planckstrasse 1, Darmstadt (Germany); Boudard, A.; Fernandez, B.; Legrain, R.; Leray, S.; Volant, C.; Wlazlo, W. [CEA Saclay, Dept. d' Astrophysique, de Physique des Particules, de Physique Nucleaire et de l' Instrumentation Associee, 91 - Gif sur Yvette (France); Benlliure, J.; Casajeros, E.; Pereira, J. [University of Santiago de Compostella (Spain); Czajkowski, S. [Centre d' Etudes Nucleaires de Bordeaux Gradignan, CENBG, CNRS-IN2P3, 33 - Gradignan (France)

    2001-07-01

    The production of spallation primary residual nuclei in thin target has been studied by measurement of isotopic yields distributions for several systems. Issues relevant for the design of accelerator-driven systems are presented. Monte-Carlo code abilities to reproduce data are studied in details; it is shown that calculations do not reproduce data in a satisfactory way. Future work orientations leading to an improvement of thin targets calculations and ultimately to a thick target simulation are discussed. (author)

  7. Coherent Scattering Investigations at the Spallation Neutron Source: a Snowmass White Paper

    Energy Technology Data Exchange (ETDEWEB)

    Akimov, D. [Moscow Engineering Physics Institute (MEPhI), Russia; Bernstein, A. [Lawrence Livermore National Laboratory (LLNL); BarbeauP., [Duke University; Barton, P. J. [Lawrence Berkeley National Laboratory (LBNL); Bolozdynya, A. [Moscow Engineering Physics Institute (MEPhI), Russia; Cabrera-Palmer, B. [Sandia National Laboratories (SNL); Cavanna, F. [Yale University; Cianciolo, Vince [ORNL; Collar, J. [University of Chicago, Enrico Fermi Institute; Cooper, R. J. [Indiana University; Dean, D. J. [Oak Ridge National Laboratory (ORNL); Efremenko, Yuri [University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL); Etenko, A. [Moscow Engineering Physics Institute (MEPhI), Russia; Fields, N. [University of Chicago, Enrico Fermi Institute; Foxe, M. [Pennsylvania State University, University Park, PA; Figueroa-Feliciano, E. [Massachusetts Institute of Technology (MIT); Fomin, N. [University of Tennessee, Knoxville (UTK); Gallmeier, F. [Oak Ridge National Laboratory (ORNL); Garishvili, I. [University of Tennessee, Knoxville (UTK); Gerling, M. [Sandia National Laboratories (SNL); Green, M. [University of North Carolina, Chapel Hill; Greene, Geoffrey [University of Tennessee, Knoxville (UTK); Hatzikoutelis, A. [University of Tennessee, Knoxville (UTK); Henning, Reyco [University of North Carolina, Chapel Hill; Hix, R. [University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL); Hogan, D. [University of California-Berkeley; Hornback, D. [University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL); Jovanovic, I. [Pennsylvania State University, University Park, PA; Hossbach, T. [Pacific Northwest National Laboratory (PNNL); Iverson, Erik B [ORNL; Klein, S. R. [Lawrence Berkeley National Laboratory (LBNL); Khromov, A. [Moscow Engineering Physics Institute (MEPhI), Russia; Link, J. [Virginia Polytechnic Institute and State University; Louis, W. [Los Alamos National Laboratory (LANL); Lu, W. [Oak Ridge National Laboratory (ORNL); Mauger, C. [Los Alamos National Laboratory (LANL); Marleau, P. [Sandia National Laboratories (SNL); Markoff, D. [North Carolina Central University, Durham; Martin, R. D. [University of South Dakota; Mueller, Paul Edward [ORNL; Newby, J. [Oak Ridge National Laboratory (ORNL); Orrell, John L. [Pacific Northwest National Laboratory (PNNL); O' Shaughnessy, C. [University of North Carolina, Chapel Hill; Penttila, Seppo [Oak Ridge National Laboratory (ORNL); Patton, K. [North Carolina State University, Raleigh; Poon, A. W. [Lawrence Berkeley National Laboratory (LBNL); Radford, David C [ORNL; Reyna, D. [Sandia National Laboratories (SNL); Ray, H. [University of Florida, Gainesville; Scholberg, K. [Duke University, North Carolina; Sosnovtsev, V. [Moscow Engineering Physics Institute (MEPhI), Russia; Tayloe, R. [Indiana University; Vetter, K. [Lawrence Berkeley National Laboratory (LBNL); Virtue, C. [Laurentian University, Canada; Wilkerson, J. [University of North Carolina, Chapel Hill; Yoo, J. [Fermi National Accelerator Laboratory (FNAL); Yu, Chang-Hong [ORNL

    2013-01-01

    The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory, Tennessee, provides an intense flux of neutrinos in the few tens-of-MeV range, with a sharply-pulsed timing structure that is beneficial for background rejection. In this white paper, we describe how the SNS source can be used for a measurement of coherent elastic neutrino-nucleus scattering (CENNS), and the physics reach of different phases of such an experimental program (CSI: Coherent Scattering Investigations at the SNS).

  8. Process technology and effects of spallation products: Circuit components, maintenance, and handling

    Energy Technology Data Exchange (ETDEWEB)

    Sigg, B.; Haines, S.J.; Dressler, R.; McManamy, T.

    1996-06-01

    Working Session D included an assessment of the status of the technology and components required to: (1) remove impurities from the liquid metal (mercury or Pb-Bi) target flow loop including the effects of spallation products, (2) provide the flow parameters necessary for target operations, and (3) maintain the target system. A series of brief presentations were made to focus the discussion on these issues. The subjects of these presentations, and presenters were: (1) Spallation products and solubilities - R. Dressler; (2) Spallation products for Pb-Bi - Y. Orlov; (3) Clean/up/impurity removal components - B. Sigg; (4) {open_quotes}Road-Map{close_quotes} and remote handling needs - T. McManamy; (5) Remote handling issues and development - M. Holding. The overall conclusion of this session was that, with the exception of (i) spallation product related processing issues, (ii) helium injection and clean-up, and (iii) specialized remote handling equipment, the technology for all other circuit components (excluding the target itself) exists. Operating systems at the Institute of Physics in Riga, Latvia (O. Lielausis) and at Ben-Gurion University in Beer Shiva, Israel (S. Lesin) have demonstrated that other liquid metal circuit components including pumps, heat exchangers, valves, seals, and piping are readily available and have been reliably used for many years. In the three areas listed above, the designs and analysis are not judged to be mature enough to determine whether and what types of technology development are required. Further design and analysis of the liquid metal target system is therefore needed to define flow circuit processing and remote handling equipment requirements and thereby identify any development needs.

  9. Spallation Fragment Investigation on Nb, Au and Pb by Using Many Stage Dynamical Model

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The formation cross section of the nuclides production of proton-induced nuclear reactions withintermediate energy is of importance for a variety of applications. For instance, the mass and chargedistribution of residual products produced in the spallation reactions needs to be studied, because it canprovide useful information for the disposal of nuclear waste and residual radioactivity generated by thespallation neutron target system. At present work, we developed the many stage dynamical model

  10. Status of R&D on mitigating the effects of pressure waves for the Spallation Neutron Source mercury target

    Science.gov (United States)

    Riemer, Bernard W.; Wendel, Mark W.; Felde, David K.; Abdou, Ashraf A.; McClintock, David A.

    2012-12-01

    The Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory has been conducting R&D on mitigating the effects of pressure waves in mercury spallation targets since 2001. More precisely, cavitation damage of the target vessel caused by the short beam pulse threatens to limit its lifetime more severely than radiation damage as well as limit its ultimate power capacity - and hence its neutron intensity performance. The R&D program has moved from verification of the beam-induced damage phenomena to study of material and surface treatments for damage resistance to the current emphasis on gas injection techniques for damage mitigation. Two techniques are being worked on: injection of small dispersed gas bubbles that mitigate the pressure waves volumetrically; and protective gas walls that isolate the vessel from the damaging effects of collapsing cavitation bubbles. The latter has demonstrated good damage mitigation during in-beam testing with limited pulses, and adequate gas wall coverage at the beam entrance window has been demonstrated with the SNS mercury target flow configuration using a full scale mercury test loop. A question on the required area coverage remains which depends on results from SNS target post irradiation examination. The small gas bubble technique has been less effective during past in-beam tests but those results were with un-optimized and un-verified bubble populations. Another round of in-beam tests with small gas bubbles is planned for 2011. The first SNS target was removed from service in mid 2009 and samples were cut from two locations at the target's beam entrance window. Through-wall damage was observed at the innermost mercury vessel wall (not a containment wall). The damage pattern suggested correlation with the local mercury flow condition which is nearly stagnant at the peak damage location. Detailed post irradiation examination of the samples is under way that will assess the erosion and measure irradiation-induced changes

  11. Heavy density liquid metal spallation target studies for Indian ADS programme

    Indian Academy of Sciences (India)

    P Sathamurthy; L M Gantayet; A K Ray

    2007-02-01

    Department of Atomic Energy, India has taken up the development of ADS in view of many attractive features like inherent safety, capability to transmute large quantities of nuclear waste, better utilization of thorium etc. A roadmap has been finalized for the development of ADS. One of the key components of the ADS is the spallation target. Considering the neutron yield, thermal-hydraulics and radiation damage issues, we are proposing to develop spallation target based on heavy density liquid metals like lead and lead-bismuth-eutectic (LBE). Both window and windowless target configurations are presently being studied. In view of the various advantages we are also studying liquid metal flow circulation based on gas lift mechanism. An R&D programme has been initiated to address various physics and technology issues of ADS target. Under this programme, mercury and LBE experimental facilities are presently being set up. Along with these facilities, computational tools related to spallation physics (FLUKA) and CFD are being developed, and the existing ones are utilized to design the entire target loop as well as sub-systems. In this presentation the details of these activities are presented.

  12. Disposal strategy of proton irradiated mercury from high power spallation sources

    Energy Technology Data Exchange (ETDEWEB)

    Chiriki, Suresh

    2010-07-01

    Large spallation sources are intended to be constructed in Europe (EURISOL: nuclear physics research facility and ESS: European Spallation Source). These facilities would accumulate more than 20 metric tons of irradiated mercury in the target, which has to be treated as highly radioactive and chemo-toxic waste. Liquid waste cannot be tolerated in European repositories. As part of this work on safety/decommissioning of high-power spallation sources, our investigations were focused mainly to study experimentally and theoretically the solidification of liquid mercury waste (selection of an adequate solid mercury form and of an immobilization matrix, chemical engineering process studies on solidification/stabilization and on encapsulating in a matrix). Based on experimental results and supported by literature Hg-chalcogens (HgS, HgSe) will be more stable in repositories than amalgams. Our irradiation experimental studies on mercury waste revealed that mercury sulfide is a reasonable solid for disposal and shows larger stability in possible accidents with water ingress in a repository. Additionally immobilization of mercury in a cement matrix and polysiloxane matrix were tested. HgS formation from liquid target mercury by a wet process is identified as a suitable formation procedure. These investigations reveal that an almost 99.9% elementary Hg conversion can be achieved and that wet process can be reasonably handled under hot cell conditions. (orig.)

  13. Experimental Study of the Phenomenology of Spallation Neutrons in a Large Lead Block

    CERN Multimedia

    Galvez Altamirano, J; Lopez, C; Perlado, J M; Perez-Navarro, A

    2002-01-01

    %PS211 %title \\\\ \\\\The purpose of PS211 is to determine how neutrons, produced by spallation inside a large Lead volume are slowed down by undergoing a very large number of scatterings, losing each time a small fraction ($\\sim$ 1\\%) of their kinetic energy. The focus is in determining the probability for a spallation neutron produced at an energy of several MeV or more, to survive capture on Lead resonances and to reach resonance energies of materials to be transmuted, such as 5.6 eV for $^{99}$Tc. This process, of Adiabatic Resonance Crossing, involves a subtle interplay between the capture resonances of the Lead medium and of selected impurities. This phenomenology of spallation neutrons in a large Lead volume, is the physics foundation of the Fast Energy Amplifier proposed by C. Rubbia, and could open up new possibilities in the incineration of long-lived nuclear waste such as Actinides or Fission Fragments (e.g. $^{99}$Tc, $^{129}$I, etc.).\\\\ \\\\334 tons of high purity Lead, installed in t7, are exposed to...

  14. Spallation Backgrounds in Super-Kamiokande Are Made in Muon-Induced Showers

    CERN Document Server

    Li, Shirley Weishi

    2015-01-01

    Crucial questions about solar and supernova neutrinos remain unanswered. Super-Kamiokande has the exposure needed for progress, but detector backgrounds are a limiting factor. A leading component is the beta decays of isotopes produced by cosmic-ray muons and their secondaries, which initiate nuclear spallation reactions. Cuts of events after and surrounding muon tracks reduce this spallation decay background by $\\simeq 90\\%$ (at a cost of $\\simeq 20\\%$ deadtime), but its rate at 6 -- 18 MeV is still dominant. A better way to cut this background was suggested in a Super-Kamiokande paper [Bays {\\it et al.}, Phys.~Rev.~D {\\bf 85}, 052007 (2012)] on a search for the diffuse supernova neutrino background. They found that spallation decays above 16 MeV were preceded near the same location by a peak in the apparent Cherenkov light profile from the muon; a more aggressive cut was applied to a limited section of the muon track, leading to decreased background without increased deadtime. We put their empirical discove...

  15. Improvements to the internal and external antenna H{sup −} ion sources at the Spallation Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Welton, R. F., E-mail: welton@ornl.gov; Han, B. X.; Murray, S. N.; Pennisi, T. R.; Pillar, C.; Santana, M.; Stockli, M. P. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37830-6471 (United States); Dudnikov, V. G. [Muons, Inc., 552 N. Batavia Avenue, Batavia, Illinois 60510 (United States); Turvey, M. W. [Villanova University, 800E. Lancaster Ave, Villanova, Pennsylvania 19085 (United States)

    2014-02-15

    The Spallation Neutron Source (SNS), a large scale neutron production facility, routinely operates with 30–40 mA peak current in the linac. Recent measurements have shown that our RF-driven internal antenna, Cs-enhanced, multi-cusp ion sources injects ∼55 mA of H{sup −} beam current (∼1 ms, 60 Hz) at 65-kV into a Radio Frequency Quadrupole (RFQ) accelerator through a closely coupled electrostatic Low-Energy Beam Transport system. Over the last several years a decrease in RFQ transmission and issues with internal antennas has stimulated source development at the SNS both for the internal and external antenna ion sources. This report discusses progress in improving internal antenna reliability, H{sup −} yield improvements which resulted from modifications to the outlet aperture assembly (applicable to both internal and external antenna sources) and studies made of the long standing problem of beam persistence with the external antenna source. The current status of the external antenna ion source will also be presented.

  16. Fabrication of Alumina Nanowires from Porous Alumina Membranes by Etching in Phosphoric Acid Solution

    Science.gov (United States)

    Wang, Xuehua; Li, Chengyong; Ma, Lianjiao; Cao, Hong; Zhang, Baohua

    Alumina nanowires (ANWs) with high aspect ratios were synthesized by the chemical etching of porous alumina membranes (PAMs) in phosphoric acid solution. The morphology and structure of ANWs were analyzed by SEM and XRD, respectively. The results showed that the typical features of ANWs are around 35 nm in diameter and around 20 μm in length, the crystalline structure of the ANWs was amorphous, which was in accordance with that of the PAMs. Furthermore, the morphology of the PAMs was characterized by AFM and SEM in detail. On the basis of AFM and SEM observations, a possible formation mechanism of ANWs was discussed, and the inhomogeneous of the dissolution between the triple points and the side walls was considered to be the essential factor deciding the formation of ANWs.

  17. Microstructural evolution of alumina-zirconia nanocomposites; Evolucao microestrutural de nanocompositos alumina-zirconia

    Energy Technology Data Exchange (ETDEWEB)

    Ojaimi, C.L.; Chinelatto, A.S.A.; Chinelatto, A.L. [Universidade Estadual de Ponta Grossa (UEPG), PR (Brazil); Pallone, E.M.J.A., E-mail: christianelago@yahoo.com.br [Universidade de Sao Paulo (USP), Pirassununga, Sao Paulo, SP (Brazil). Faculdade de Zootecnia e Engenharia de Alimentos

    2012-07-01

    Ceramic materials have limited use due to their brittleness. The inclusion of nanosized particles in a ceramic matrix, which are called nanocomposites, and ceramic processing control by controlling the grain size and densification can aid in obtaining ceramic products of greater strength and toughness. Studies showed that the zirconia nano inclusions in the matrix of alumina favors an increase in mechanical properties by inhibiting the grain growth of the matrix and not by the mechanism of the transformation toughening phase of zirconia. In this work, the microstructural evolution of alumina nanocomposites containing 15% by volume of nanometric zirconia was studied. From the results it was possible to understand the sintering process of these nanocomposites. (author)

  18. Ballistic Performance of Alumina and Zirconia-toughened Alumina Against 7.62 Armour Piercing Projectile

    Directory of Open Access Journals (Sweden)

    S G. Savio

    2014-09-01

    Full Text Available A study was carried out to compare the ballistic performance of high purity alumina and zirconia-toughened alumina (ZTA using depth of penetration (DoP test configuration against 7.62 mm armour piercing (AP ammunition. The effect of tile thickness on the differential efficiency factor (DEF was studied for tile thickness in the range of 3 mm to 6 mm for alumina tiles and 3 mm to 5 mm for ZTA tiles. The DEF is found to increase as tile thickness increases. An analysis on the failed shots showed that the residual shot weight does not follow a single linear relationship with ceramic tile thickness unlike the residual DoP for all thicknesses of tiles. Post-ballistic analysis on ceramic powder for particle size distribution was carried out and the results are presented.Defence Science Journal, Vol. 64, No. 5, September 2014, pp.477-483, DOI:http://dx.doi.org/10.14429/dsj.64.6745

  19. Design and fabrication of alumina micro reciprocating engine

    Institute of Scientific and Technical Information of China (English)

    JIN Peng; GAO Yu-long; LIU Nan; JIANG Kylie

    2008-01-01

    Microengines are regarded as the potential replacements for batteries. Aimed at the unsatisfactory thermal property of silicon used in the combustion chambers, ceramics are chosen as the construction material in this paper. The fabrication process where alumina has been chosen as the microengine material is discussed. Vigorous FEA has been carried out, and it is found that the material satisfies the stress and deformation require-ments of the design. Then the alumina fabrication process is described. Soft reusable polydimethylsiloxane (PDMS) moulds are produced from SU-8 resist masters, and alumina microengine parts are produced using the PDMS moulds. Images of the ceramic components show that the fabrication satisfies the design requirements.

  20. Processing of silicon nitride and alumina nanosize powders

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, E.J.; Piermarini, G.; Hockey, B.; Malghan, S.G. [National Inst. of Standard and Technology, Gaithersburg, MD (United States)

    1995-08-01

    The effects of pressure on the compaction and subsequent processing of nanosize {gamma} alumina powders were studied. A 3 mm diameter piston/cylinder die was used to compact the nanosize powders to pressures of 1 and 2.5 GPa. The green bodies were sintered at temperatures up to 1600{degrees}C. Results show that green body density can be increased by higher compaction pressures. It appears that as a result of the {gamma}-to-{alpha} transformation in alumina, higher green density does not necessarily produce a higher density sintered alumina body. The microstructures of the sintered bodies are described in terms of porosity and phase content.

  1. Alumina Paste Sublimation Suppression Barrier for Thermoelectric Device

    Science.gov (United States)

    Paik, Jong-Ah (Inventor); Caillat, Thierry (Inventor)

    2014-01-01

    Alumina as a sublimation suppression barrier for a Zintl thermoelectric material in a thermoelectric power generation device operating at high temperature, e.g. at or above 1000K, is disclosed. The Zintl thermoelectric material may comprise Yb.sub.14MnSb.sub.11. The alumina may be applied as an adhesive paste dried and cured on a substantially oxide free surface of the Zintl thermoelectric material and polished to a final thickness. The sublimation suppression barrier may be finalized by baking out the alumina layer on the Zintl thermoelectric material until it becomes substantially clogged with ytterbia.

  2. Special requirements for alumina ceramic of ESG electrode bowl

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jun-an; XUE Kai; ZHANG Jia-tai; ZHANG Qiang

    2004-01-01

    At present ESG (Electrostatic Suspended Gyro) is the most precise inertia element in the world. The electrode bowl, which has direct effect on the precision of ESG, is a key part to ESG. Through the analysis of the function and characteristic of the electrode bowl in hollow rotor ESG and the present situation of new material development in the world, the alumina ceramic is regarded as the best material for the electrode bowl of hollow rotor ESG. By analyzing the present situation of alumina ceramic in the world, main technique requirements have been put forward for the alumina ceramic of ESG electrode bowl which is also fit for solid rotor ESG.

  3. Wenshan’s 800,000-ton Alumina Project Completed

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    <正>On September 26,2012,the completion ceremony of the 800,000-ton alumina project was held at the alumina factory in Matang Industrial Park, Wenshan city,Yunnan.Wenshan’s 800,000-ton alumina project and its supporting mining construction projects have been listed as one of 20 major industrial construction projects of Yunnan. The project covers an area of approximately 5,500 mu,with an estimated total investment of RMB 4,987 million. It is invested and built

  4. Porous Alumina Based Capacitive MEMS RH Sensor

    CERN Document Server

    Juhasz, L; Timar-Horvath, Veronika; Desmulliez, Marc; Dhariwal, Resh

    2008-01-01

    The aim of a joint research and development project at the BME and HWU is to produce a cheap, reliable, low-power and CMOS-MEMS process compatible capacitive type relative humidity (RH) sensor that can be incorporated into a state-of-the-art, wireless sensor network. In this paper we discuss the preparation of our new capacitive structure based on post-CMOS MEMS processes and the methods which were used to characterize the thin film porous alumina sensing layer. The average sensitivity is approx. 15 pF/RH% which is more than a magnitude higher than the values found in the literature. The sensor is equipped with integrated resistive heating, which can be used for maintenance to reduce drift, or for keeping the sensing layer at elevated temperature, as an alternative method for temperature-dependence cancellation.

  5. Fracture simulation for zirconia toughened alumina microstructure

    CERN Document Server

    Kim, Kyungmok; Forest, Bernard

    2013-01-01

    Purpose - The purpose of this paper is to describe finite element modelling for fracture and fatigue behaviour of zirconia toughened alumina microstructures. Design/methodology/approach - A two-dimensional finite element model is developed with an actual $Al{_2}O{_3}$ - 10 vol% $ZrO{_2}$ microstructure. A bilinear, time-independent cohesive zone law is implemented for describing fracture behaviour of grain boundaries. Simulation conditions are similar to those found at contact between a head and a cup of hip prosthesis. Residual stresses arisen from the mismatch of thermal coefficient between grains are determined. Then, effects of a micro-void and contact stress magnitude are investigated with models containing residual stresses. For the purpose of simulating fatigue behaviour, cyclic loadings are applied to the models. Findings - Results show that crack density is gradually increased with increasing magnitude of contact stress or number of fatigue cycles. It is also identified that a micro-void brings about...

  6. Crystallography of Alumina-YAG-Eutectic

    Science.gov (United States)

    Farmer, Serene C.; Sayir, Ali; Dickerson, Robert M.; Matson, Lawrence E.

    2000-01-01

    Multiple descriptions of the alumina-YAG eutectic crystallography appear in the ceramic literature. The orientation between two phases in a eutectic system has direct impact on residual stress, morphology, microstructural stability, and high temperature mechanical properties. A study to demonstrate that the different crystallographic relationships can be correlated with different growth constraints was undertaken. Fibers produced by Laser-Heated Float Zone (LHFZ) and Edge-defined Film-fed Growth (EFG) were examined. A map of the orientation relationship between Al2O3 and Y3Al5O12 and their relationship to the fiber growth axis as a function of pull rate are presented. Regions in which a single orientation predominates are identified.

  7. Electrochemical modification process of anodic alumina membrane

    Institute of Scientific and Technical Information of China (English)

    YU Mei; LIU Jian-hua; LI Song-mei

    2006-01-01

    The modification procedure of anodic alumina membrane(AAM) was studied. The AAM structure after modification was characterized by nickel nanowires prepared in AAM. Scanning electron microscopy was used to characterize the topography and structure properties of the AAM and nickel nanowires. The transformation of the current during the voltage reduction was studied. The mechanism of current and structure change during modification was discussed. The results show that a root structure produces after the AAM modification. The length of the root structure depends on the velocity of the voltage reduction. Slow voltage reduction leads to a large length of the root structure,otherwise,a short length of the root structure. At the end of the modification,the barrier layer is thin enough to be passed by electrons. Hence,the direct electrodeposition of one-dimensional nanowires can be carried out on the AAM with barrier layer and aluminum matrix successfully without any other treatments.

  8. Aluminum matrix composites reinforced with alumina nanoparticles

    CERN Document Server

    Casati, Riccardo

    2016-01-01

    This book describes the latest efforts to develop aluminum nanocomposites with enhanced damping and mechanical properties and good workability. The nanocomposites exhibited high strength, improved damping behavior and good ductility, making them suitable for use as wires. Since the production of metal matrix nanocomposites by conventional melting processes is considered extremely problematic (because of the poor wettability of the nanoparticles), different powder metallurgy routes were investigated, including high-energy ball milling and unconventional compaction methods. Special attention was paid to the structural characterization at the micro- and nanoscale, as uniform nanoparticle dispersion in metal matrix is of prime importance. The aluminum nanocomposites displayed an ultrafine microstructure reinforced with alumina nanoparticles produced in situ or added ex situ. The physical, mechanical and functional characteristics of the materials produced were evaluated using different mechanical tests and micros...

  9. Characterization of Glasses in One Type of Alumina Rich Fly Ash by Chemical Digestion Methods: Implications for Alumina Extraction

    Directory of Open Access Journals (Sweden)

    Lijun Zhao

    2016-01-01

    Full Text Available In recent years, one type of alumina rich fly ash (ARFA with about 50 wt% of alumina has been extensively investigated for alumina extraction in China. Due to the silica in ARFA, alumina extraction would have to generate a huge amount of solid waste. There is a growing interest in the glasses in ARFA, because they are composed mainly of silica and could be removed prior to alumina extraction. In this work, the glasses in ARFA have been investigated by chemical methods, that is, acid and base digestions. The chemical compositions have been measured by XRF for ARFA from the digestion processes. The K2O standard, XRD, and FTIR spectroscopies were successfully used to define the digestions processes, and size analysis and SEM-EDX provided rich information on particle transformations. As a result, acid and base digestion methods were found to produce very similar results for the glasses in ARFA. The K2O standard was attributed to the formation of glasses by illites, and TiO2 and Fe2O3 were proposed to originate from ilmenite in alumina rich coals (ARC. Some implications of the results were also discussed for the alumina extraction from ARFA.

  10. European Spallation Source ESS. Spanish participation in the ESS Primary system design; Fuente Europea de Spallation ESS. Participacion espanola en el diseno del sistema primario de la ESS

    Energy Technology Data Exchange (ETDEWEB)

    Dominguez, M. T.; Albisu, F.

    2001-07-01

    Neutron scattering provides basic microscopic information on the structure and dynamics of materials which underpins our understanding of condensed matter in fields as diverse as biology, material science chemistry, earth sciences and physics. Europe is preeminent, in this field and the current proposal for a next generation neutron source, the European Spallation source (ESS), will ensure that neutron beams of the highest quality are available early next century to a broad spectrum of users from academia and industry. In the Large Facilities Report to the Commission of the European Community (CEC) in 1990, the Neutron Study Panel underlined the continuing need for neutron scattering and recognised that a major initiative was necessary to secure an effective on-going neutron science programme in Europe for the year 2000 and beyond. (Author)

  11. Anodisation with dynamic current control for tailored alumina coatings

    Science.gov (United States)

    Sieber, M.; Althöfer, I.; Höhlich, D.; Scharf, I.; Böttger, D.; Böttger, S.; Böttger, E.; Lampke, T.

    2016-03-01

    The anodic oxidation process is commonly used to refine the surface of aluminium and its alloys. Compared to the substrate, the alumina layers produced by anodising exhibit an increased hardness and chemical resistance. Thus, the corrosion and wear resistance are generally improved. The coatings are also electrically isolating and may serve decorative purposes. Applying a time-variant, dynamic electrical process control by pulse-current or current-steps is a promising approach to improve the coating properties, which is partially deployed in an industrial scale. In the present work, the influence of dynamic electrical process control on the coating properties is examined by means of a design of experiments (DOE). The effects of various electrolyte compositions and temperatures as well as processing time are considered with regard to coating thickness, hardness, wear resistance and the electrical energy consumption during the formation of the coatings. Information about the statistical significance of the effects of the parameters on the considered properties is obtained by an analysis of variance (ANOVA).

  12. Fused Cast Alumina Refractory Products for Glass Tank Furnace

    Institute of Scientific and Technical Information of China (English)

    SHEN Keyin

    2006-01-01

    @@ 1 Subject and Scope The standard specifies the requirement, testing method, inspection rule and requirements for the labeling, packing, shipping and storing of the fused cast alumina refractory products for glass tanks.

  13. Direct spray pyrolysis of aluminum chloride solution for alumina preparation

    Institute of Scientific and Technical Information of China (English)

    吕国志; 张廷安; 王龙; 马思达; 豆志河; 刘燕

    2014-01-01

    The effects of pyrolysis mode and pyrolysis parameters on Cl content in alumina were investigated, and the alumina products were characterized by XRD, SEM and ASAP. The experimental results indicate that the spray pyrolysis efficiency is higher than that of static pyrolysis process, and the reaction and evaporation process lead to a multi-plot state of the alumina products by spray pyrolysis. Aluminum phase starts to transform intoγ-Al2O3 at spray pyrolysis temperature of 600 °C, which is about 200 °C lower than that of static pyrolysis process. The primary particle size of γ-Al2O3 product is 27.62 nm, and Cl content in alumina products is 0.38%at 800 °C for 20 min.

  14. High Alumina Refractory Bricks for Electric Arc Furnace Roofs

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ 1 Scope This standard specifies the sort, technical requirement, test method, inspection rules, marking, packing, transportation, storage and quality certification of high alumina refractory bricks for electric arc furnace roofs.

  15. Aluminum microstructures on anodic alumina for aluminum wiring boards.

    Science.gov (United States)

    Jha, Himendra; Kikuchi, Tatsuya; Sakairi, Masatoshi; Takahashi, Hideaki

    2010-03-01

    The paper demonstrates simple methods for the fabrication of aluminum microstructures on the anodic oxide film of aluminum. The aluminum sheets were first engraved (patterned) either by laser beam or by embossing to form deep grooves on the surface. One side of the sheet was then anodized, blocking the other side by using polymer mask to form the anodic alumina. Because of the lower thickness at the bottom part of the grooves, the part was completely anodized before the complete oxidation of the other parts. Such selectively complete anodizing resulted in the patterns of metallic aluminum on anodic alumina. Using the technique, we fabricated microstructures such as line patterns and a simple wiring circuit-board-like structure on the anodic alumina. The aluminum microstructures fabricated by the techniques were embedded in anodic alumina/aluminum sheet, and this technique is promising for applications in electronic packaging and devices.

  16. High Alumina Refractory Mortars GB/T 2994-2008

    Institute of Scientific and Technical Information of China (English)

    Wang Jing; Chai Junlan

    2009-01-01

    @@ 1 Scope This standard specifies the classification, techni-cal requirements, test methods, quality appraisal pro-cedure, packing, marking, transportation, storage and quality certificate of high alumina refractory mortars.

  17. Monitoring method of neutron flux for the spallation target used in an accelerator driven sub-critical systems

    CERN Document Server

    Zhao, Qiang; Yang, Lei; Zhang, Xueying; Cui, Wenjuan; Chen, Zhiqiang; Xu, Hushan

    2015-01-01

    In this paper, we study the monitoring method of neutron flux for the spallation target used in an accelerator driven sub-critical (ADS) system, where the spallation target located vertically at the centre of a sub-critical core is bombarded vertically by the high-energy protons from an accelerator. First, by considering the characteristics in the spatial variation of neutron flux from the spallation target, we propose the following multi-point measurement technique, i.e. the spallation neutron flux should be measured at multiple vertical locations. To explain why the flux should be measured at multiple locations, we have studied the neutron production from tungsten target bombarded by a 250 MeV-proton beam with the Geant4-based Monte Carlo simulations. The simulation results have indicated that the neutron flux at the central location is up to three orders of magnitude higher than the flux at the lower locations. Secondly, we have developed an effective technique in order to measure the spallation neutron fl...

  18. The Effect of Beam Intensity on Temperature Distribution in ADS Windowless Lead-Bismuth Eutectic Spallation Target

    Directory of Open Access Journals (Sweden)

    Jie Liu

    2014-01-01

    Full Text Available The spallation target is the component coupling the accelerator and the reactor and is regarded as the “heart” of the accelerator driven system (ADS. Heavy liquid metal lead-bismuth eutectic (LBE is served as core coolant and spallation material to carry away heat deposition of spallation reaction and produce high flux neutron. So it is very important to study the heat transfer process in the target. In this paper, the steady-state flow pattern has been numerically obtained and taken as the input for the nuclear physics calculation, and then the distribution of the extreme large power density of the heat load is imported back to the computational fluid dynamics as the source term in the energy equation. Through the coupling, the transient and steady-state temperature distribution in the windowless spallation target is obtained and analyzed based on the flow process and heat transfer. Comparison of the temperature distribution with the different beam intensity shows that its shape is the same as broken wing of the butterfly. Nevertheless, the maximum temperature as well as the temperature gradient is different. The results play an important role and can be applied to the further design and optimization of the ADS windowless spallation target.

  19. Modelling of the spallation reaction: analysis and testing of nuclear models; Simulation de la spallation: analyse et test des modeles nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Toccoli, C

    2000-04-03

    The spallation reaction is considered as a 2-step process. First a very quick stage (10{sup -22}, 10{sup -29} s) which corresponds to the individual interaction between the incident projectile and nucleons, this interaction is followed by a series of nucleon-nucleon collisions (intranuclear cascade) during which fast particles are emitted, the nucleus is left in a strongly excited level. Secondly a slower stage (10{sup -18}, 10{sup -19} s) during which the nucleus is expected to de-excite completely. This de-excitation is performed by evaporation of light particles (n, p, d, t, {sup 3}He, {sup 4}He) or/and fission or/and fragmentation. The HETC code has been designed to simulate spallation reactions, this simulation is based on the 2-steps process and on several models of intranuclear cascades (Bertini model, Cugnon model, Helder Duarte model), the evaporation model relies on the statistical theory of Weiskopf-Ewing. The purpose of this work is to evaluate the ability of the HETC code to predict experimental results. A methodology about the comparison of relevant experimental data with results of calculation is presented and a preliminary estimation of the systematic error of the HETC code is proposed. The main problem of cascade models originates in the difficulty of simulating inelastic nucleon-nucleon collisions, the emission of pions is over-estimated and corresponding differential spectra are badly reproduced. The inaccuracy of cascade models has a great impact to determine the excited level of the nucleus at the end of the first step and indirectly on the distribution of final residual nuclei. The test of the evaporation model has shown that the emission of high energy light particles is under-estimated. (A.C.)

  20. Preparation of mesoporous alumina films by anodization: Effect of pretreatments on the aluminum surface and MTBE catalytic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez, A.L., E-mail: avazquezd@ipn.m [Departamento de Ingenieria Metalurgica, ESIQIE-IPN, AP 75-876, Mexico, D.F. (Mexico); Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Lazaro Cardenas 152, C.P. 07730, Mexico, D.F. (Mexico); Carrera, R. [Departamento de Ingenieria Metalurgica, ESIQIE-IPN, AP 75-876, Mexico, D.F. (Mexico); Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Lazaro Cardenas 152, C.P. 07730, Mexico, D.F. (Mexico); Arce, E. [Departamento de Ingenieria Metalurgica, ESIQIE-IPN, AP 75-876, Mexico, D.F. (Mexico); Castillo, N. [CINVESTAV, Departamento de Fisica. Av. IPN 2508, 07360, Mexico, D.F (Mexico); Castillo, S. [Departamento de Ingenieria Metalurgica, ESIQIE-IPN, AP 75-876, Mexico, D.F. (Mexico); Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Lazaro Cardenas 152, C.P. 07730, Mexico, D.F. (Mexico); Moran-Pineda, M. [Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Lazaro Cardenas 152, C.P. 07730, Mexico, D.F. (Mexico)

    2009-08-26

    Mesoporous materials are both scientifically and technologically important because of the presence of voids of controllable dimensions at atomic, molecular, and nanometric scales. Over the last decade, there has been both an increasing interest and research effort in the synthesis and characterization of these types of materials. The purposes of this work are to study the physical and chemical changes in the properties of mesoporous alumina films produced by anodization in sulphuric acid by different pretreatments on the aluminium surface such as mechanical polishing [MP] and electropolishing [EP]; and to compare their properties such as morphology, structure and catalytic activity with those present in commercial alumina. The morphologic and physical characterizations of the alumina film samples were carried out by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The chemical evaluations were performed by the oxidation of methyl-tert-butyl-ether (MTBE) at 400 deg. C under O{sub 2}/He oxidizing conditions (Praxair, 2.0% O{sub 2}/He balance). According to the results, the samples that presented higher activities than those in Al{sub 2}O{sub 3}/Al [MP] and commercial alumina in the MTBE oxidation (69%), were those prepared by Al{sub 2}O{sub 3}/Al [EP]. The average mesoporous diameter was 17 nm, and the morphological shape was equiaxial; thus, that pore distribution was the smallest of all with a homogeneous distribution.

  1. Electronic Structure of High-Pressure Alumina Polymorphs

    Institute of Scientific and Technical Information of China (English)

    LIU Xiao-Lei; DUAN Wen-Hui; GU Bing-Lin

    2000-01-01

    Electronic properties are investigated for three alumina polymorphs (corundum, Rb2 O3 (Ⅱ) and Pbnm perovskite),which are predicted as the stable structures under different pressure range, by means of the first-principles molecular dynamics method within local density functional framework. The similarity in electronic properties of the polymorphs of alumina is observed. The effect of possible phase transitions on ruby (Cr+3-doped Al2 O3)fluorescences is discussed.

  2. CSL grain boundary distribution in alumina and zirconia ceramics

    OpenAIRE

    Vonlanthen, Pierre; Grobéty, Bernard

    2008-01-01

    The distributions of general and coincidence site lattice (CSL) grain boundaries (GBs) in texture-free alumina and zirconia ceramics sintered at two different temperatures were investigated based on electron backscatter diffraction (EBSD) measurements. Results were compared with the distributions obtained from random 2D spatial models and with calculated random distributions reported in the literature. All alumina samples independent on sintering temperature show the same characteristic devia...

  3. Antibacterial activity of zinc oxide-coated nanoporous alumina

    Energy Technology Data Exchange (ETDEWEB)

    Skoog, S.A. [Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Box 7115, Raleigh, NC 27695-7115 (United States); Bayati, M.R. [Department of Materials Science and Engineering, North Carolina State University, Box 7907, Raleigh, NC 27695-7907 (United States); Petrochenko, P.E. [Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Box 7115, Raleigh, NC 27695-7115 (United States); Division of Biology, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD 20993 (United States); Stafslien, S.; Daniels, J.; Cilz, N. [Center for Nanoscale Science and Engineering, North Dakota State University, 1805 Research Park Drive, Fargo, ND 58102 (United States); Comstock, D.J.; Elam, J.W. [Energy Systems Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Narayan, R.J., E-mail: roger_narayan@msn.com [Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Box 7115, Raleigh, NC 27695-7115 (United States); Department of Materials Science and Engineering, North Carolina State University, Box 7907, Raleigh, NC 27695-7907 (United States)

    2012-07-25

    Highlights: Black-Right-Pointing-Pointer Atomic layer deposition was used to deposit ZnO on nanoporous alumina membranes. Black-Right-Pointing-Pointer Scanning electron microscopy showed continuous coatings of zinc oxide nanocrystals. Black-Right-Pointing-Pointer Activity against B. subtilis, E. coli, S. aureus, and S. epidermidis was shown. - Abstract: Nanoporous alumina membranes, also known as anodized aluminum oxide membranes, are being investigated for use in treatment of burn injuries and other skin wounds. In this study, atomic layer deposition was used for coating the surfaces of nanoporous alumina membranes with zinc oxide. Agar diffusion assays were used to show activity of zinc oxide-coated nanoporous alumina membranes against several bacteria found on the skin surface, including Bacillus subtilis, Escherichia coli, Staphylococcus aureus, and Staphylococcus epidermidis. On the other hand, zinc oxide-coated nanoporous alumina membranes did not show activity against Pseudomonas aeruginosa, Enterococcus faecalis, and Candida albicans. These results suggest that zinc oxide-coated nanoporous alumina membranes have activity against some Gram-positive and Gram-negative bacteria that are associated with skin colonization and skin infection.

  4. Porous alumina and zirconia ceramics with tailored thermal conductivity

    Science.gov (United States)

    Gregorová, E.; Pabst, W.; Sofer, Z.; Jankovský, O.; Matějíček, J.

    2012-11-01

    The thermal conductivity of porous ceramics can be tailored by slip casting and uniaxial dry pressing, using either fugitive pore formers (saccharides) or partial sintering. Porous alumina and zirconia ceramics have been prepared using appropriate powder types (ungranulated for casting, granulated for pressing) and identical firing regimes (but different maximum temperatures in the case of partial sintering). Thermal diffusivities have been measured by the laser- and xenon-flash method and transformed into relative thermal conductivities, which enable a temperature-independent comparison between different materials. While the porosity can be controlled in a similar way for both materials when using pore formers, partial sintering exhibits characteristic differences between alumina and zirconia (for alumina porosities below 45 %, full density above 1600 °C, for zirconia porosities below 60 %, full density above 1300 °C). The different compaction behavior of alumina and zirconia (porosity after pressing 0.465 and 0.597, respectively) is reflected in the fact that for alumina the relative conductivity data of partially sintered materials are below the exponential prediction, while for zirconia they coincide with the latter. Notwithstanding these characteristic differences, for both alumina and zirconia it is possible to tailor the thermal conductivity from 100 % down to approx. 15 % of the solid phase value.

  5. Procoagulant behavior and platelet microparticle generation on nanoporous alumina.

    Science.gov (United States)

    Ferraz, Natalia; Hong, Jaan; Karlsson Ott, Marjam

    2010-05-01

    In the present work, we have investigated platelet microparticle (PMP) generation in whole blood after contact with nanoporous alumina. Alumina membranes with pore sizes of 20 and 200 nm in diameter were incubated with whole blood and the number of PMP in the fluid phase was determined by flow cytometry. The role of the complement system in PMP generation was investigated using an analog of the potent complement inhibitor compstatin. Moreover, the procoagulant activity of the two pore size membranes were compared by measuring thrombin formation. Results indicated that PMP were not present in the fluid phase after whole blood contact with either of the alumina membranes. However, scanning electron microscope micrographs clearly showed the presence of PMP clusters on the 200 nm pore size alumina, while PMP were practically absent on the 20 nm membrane. We probed no influence of complement activation in PMP generation and adhesion and we hypothesize that other specific material-related protein-platelet interactions are taking place. A clear difference in procoagulant activity between the membranes could also be seen, 20 nm alumina showed 100% higher procoagulant activity than 200 nm membrane. By combining surface evaluation and flow cytometry analyses of the fluid phase, we are able to conclude that 200 nm pore size alumina promotes PMP generation and adhesion while the 20 nm membrane does not appreciably cause any release or adhesion of PMP, thus indicating a direct connection between PMP generation and nanoporosity.

  6. Dynamic yield and tensile strengths of spark plasma sintered alumina

    Science.gov (United States)

    Girlitsky, I.; Zaretsky, E.; Kalabukhov, S.; Dariel, M.; Frage, N.

    2014-05-01

    Fully dense alumina samples with 0.6 μm grain size were produced from alumina powder using Spark Plasma Sintering and tested in two types of VISAR-instrumented planar impact tests. In the tests of the first type the samples of 0.28 to 6-mm thickness were loaded by 1-mm tungsten impactors accelerated up to a velocity of about 1 km/s. These tests were aimed to study the Hugoniot elastic limit (HEL) of the SPS-processed alumina and the decay of the elastic precursor wave with propagation distance. In the second type of test the samples of ~3-mm thickness were loaded by 1-mm copper impactors accelerated up to velocities 100-1000 m/s. These tests were aimed to study the dynamic tensile (spall) strength of the alumina. The data on tensile fracture of the alumina demonstrate a monotonic decline of the spall strength with the amplitude of the loading stress pulse. The data on the decay of the elastic precursor wave allows for determining the rates of the irreversible (inelastic) strains in the SPS-processed alumina at the initial stages of shock-induced inelastic deformation and, thus, to derive some conclusions concerning the mechanisms responsible of the deformation.

  7. Adsorption of itaconic acid from aqueous solutions onto alumina

    Directory of Open Access Journals (Sweden)

    JELENA J. GULICOVSKI

    2008-08-01

    Full Text Available Itaconic acid, IA (C5H6O4, was investigated as a potential flocculant for the aqueous processing of alumina powders. The adsorption of IA, as a function of its concentration and pH value of the solution, onto the alumina surface was studied by the solution depletion method. The stability of the suspensions in the presence of itaconic acid was evaluated in light of the surface charge of the alumina powder used, the degree of dissociation of IA, as well as the sedimentation behavior and rheology of the suspensions. It was found that the adsorption process is extremely pH dependent; the maximum adsorption of IA onto alumina surface occurring at a pH close to the value of the first IA dissociation constant, pKa1. Also, IA does not influence the value of the point of zero charge of alumina. It was shown that IA represents an efficient flocculant for concentrated acidic alumina suspensions.

  8. Influence of additives on the stability of the phases of alumina; Influencia de aditivos na estabilidade das fases da alumina

    Energy Technology Data Exchange (ETDEWEB)

    Rosario, D.C.C.; Gouvea, D., E-mail: deisedorosario@usp.br [Universidade de Sao Paulo (USP), SP (Brazil). Departamento de Engenharia Metalurgica e de Materiais. Laboratorio de Processos Ceramicos

    2011-07-01

    Problems with the stability of gamma alumina in catalytic reactions have been solved with the inclusion of additives during the synthesis of alumina. These additives stabilize the temperature of phase transition allowing the use of metastable alumina at high temperatures, but the mechanisms of action of additives are not well defined. It is known that each family of additive or additives behaves in different ways for this stabilization. This work aimed to study the performance of MgO and ZrO{sub 2}, respectively at different concentrations in alumina synthesized via Pechini. The samples were analyzed by DSC, X-ray diffraction, measurement of specific surface area by BET analysis, and infrared analysis. The results showed an increase in transition temperature for both additives, and a different changes for specific surface area, showing that MgO and ZrO{sub 2} work on improving the stability but with distinct mechanisms. (author)

  9. Bond strength, bond stress and spallation mechanisms of thermal barrier coatings

    Energy Technology Data Exchange (ETDEWEB)

    Gell, M.; Krishnakumar, V.; McCarron, K.; Barber, B.; Sohn, Y.-H. [Connecticut Univ., Storrs, CT (United States). Dept. of Metall. and Mater. Eng.; Eric, J. [Connecticut Univ., Storrs, CT (United States). Dept. of Mechanical Engineering; Tolpygo, V.K.

    1999-11-01

    Five production thermal barrier coatings were thermally cycled between room temperature and 1121 C (2050 F) to determine relative spallation life. Bond strength measurements were made using a modified ASTM direct pull-test. Bond stress measurements were made in the thermally grown oxide using a laser photoluminescence technique. Bond strength and bond stress measurements were conducted on two electron beam physical vapor deposition coatings as a function of thermal cycling. Each coating showed characteristic values of as-coated strength and stress and changes in strength and stress with thermal cycling. These variations in strength and stress with thermal cycling are related to oxidation and micro-debonding effects. (orig.)

  10. Opportunities for Neutrino Physics at the Spallation Neutron Source: A White Paper

    CERN Document Server

    Bolozdynya, A; Efremenko, Y; Garvey, G T; Gudkov, V; Hatzikoutelis, A; Hix, W R; Louis, W C; Link, J M; Markoff, D M; Mills, G B; Patton, K; Ray, H; Scholberg, K; Van de Water, R G; Virtue, C; White, D H; Yen, S; Yoo, J

    2012-01-01

    The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory, Tennessee, provides an intense flux of neutrinos in the few tens-of-MeV range, with a sharply-pulsed timing structure that is beneficial for background rejection. In this document, the product of a workshop at the SNS in May 2012, we describe this free, high-quality stopped-pion neutrino source and outline various physics that could be done using it. We describe without prioritization some specific experimental configurations that could address these physics topics.

  11. First results of the new n-TOF spallation target commissioning

    Energy Technology Data Exchange (ETDEWEB)

    Berthoumieux, E.; Andriamonje, S.; Andrzejewski, J.; Audouin, L.; Becares, V.; Becvar, F.; Belloni, F.; Berthier, B.; Brugger, M.; Calviani, M.; Calvino, F.; Cano-Ott, D.; Carrapico, C.; Cennini, P.; Cerutti, F.; Chiaveri, E.; Chin, M.; Colonna, N.; Cortes, G.; Cortes-Giraldo, M.A.; Dillmann, I.; Domingo-Pardo, C.; Duran, I.; Fernandez-Ordonez, M.; Ferrari, A.; Ganesan, S.; Giubrone, G.; Gomez-Hornillos, M.B.; Goncalves, I.F.; Gonzalez-Romero, E.; Gramegna, F.; Guerrero, C.; Gunsing, F.; Harrisopulos, S.; Heil, M.; Ioannides, K.; Jericha, E.; Kadi, Y.; Kappeler, F.; Karadimos, D.; Krticka, M.; Lebbos, E.; Lederer, C.; Leeb, H.; Losito, R.; Lozano, M.; Marganiec, J.; Marrone, S.; Martinez, T.; Massimi, C.; Mastinu, P.F.; Meaze, M.; Mendoza, E.; Mengoni, A.; Milazzo, P.M.; Mosconi, M.; Nolte, R.; Paradela, C.; Pavlik, A.; Perkowski, J.; Plag, R.; Praena, J.; Quesada, J.M.; Rauscher, T.; Reifarth, R.; Roman, F.; Rubbia, C.; Sarmento, R.; Tagliente, G.; Tain, J.L.; Tarrio, D.; Tassan-Got, L.; Vannini, G.; Variale, V.; Vaz, P.; Ventura, A.; Vlachoudis, V.; Vlastou, R.; Vykydal, Z.; Wallner, A.; Weib, C.

    2009-07-01

    The Neutron Time of Flight facility n-TOF located at CERN started to take data in 2001. Due to an increase of radioactivity released in the cooling water the experiment was stopped by end of 2004. In 2008 a new spallation target has been installed. In 2009 the collaboration has performed the full commissioning of the facility, consisting in the determination of the fluence, the beam profile, and the energy resolution of the neutron beam. After a brief description of the new target assembly, very preliminary results concerning the shape of the neutron fluence and its absolute value will be given. Measurements of the neutron beam profile will also be shown. (authors)

  12. Cooperative effort between consorcio European Spallation Source Bilbao and Oak Ridge National Laboratory spallation neutron source for manufacturing and testing of the Jema-designed modulator system CRADA/NFE-13-04600

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, David E [ORNL

    2017-01-02

    The JEMA modulator was originally developed for the European Spallation Source (ESS) when Spain was under consideration as a location for the ESS facility. Discussions ensued and the Spallation Neutron Source Research Accelerator Division agreed to form a collaboration with ESS-Bilbao (ESS-B) consortium to provide services for specifying the requirements for a version of the modulator capable of operating twelve 550 kW klystrons, monitoring the technical progress on the contract with JEMA, installing and commissioning the modulator at SNS, and performing a 30 day full power test. This work was recently completed, and this report discusses those activities with primary emphasis on the installation and testing activities.

  13. Spallation Neutrons and Pressure SNAP DE-FG02-03ER46085 CLOSE-OUT MAY 2009

    Energy Technology Data Exchange (ETDEWEB)

    Parise, John B

    2009-05-22

    The purpose of the grant was to build a community of scientist and to draw upon their expertise to design and build the world's first dedicated high pressure beamline at a spallation source - the so called Spallation Neutron And Pressure (SNAP) beamline at the Spallation Neutron Source (SNS) at OAk Ridge NAtional LAboratory. . Key to this endeavor was an annual meeting attended by the instrument design team and the executive committee. The discussions at those meeting set an ambitious agenda for beamline design and construction and highlighted key science areas of interest for the community. This report documents in 4 appendices the deliberations at the annual SNAP meetings and the evolution of the beamline optics from concept to construction. The appendices also contain key science opportunities for extreme conditions research.

  14. Spallation Source Modelling for an ADS Using the MCNPX and GEANT4 Packages for Sensitivity Analysis of Reactivity

    Science.gov (United States)

    Antolin, M. Q.; Marinho, F.; Palma, D. A. P.; Martinez, A. S.

    2014-04-01

    A simulation for the time evolution of the MYRRHA conceptual reactor was developed. The SERPENT code was used to simulate the nuclear fuel depletion and the spallation source which drives the system was simulated using both MCNPX and GEANT4 packages. The obtained results for the neutron energy spectrum from the spallation are coherent with each other and were used as input for the SERPENT code which simulated a constant power operation regime. The obtained results show that the criticality of the system is not sensitive to the spallation models employed and only relative small deviations with respect to the inverse kinetic model coming from the point kinetic equations proposed by Gandini were observed.

  15. Effect of alumina composition and surface integrity in alumina/epoxy composites on the ultrasonic attenuation properties.

    Science.gov (United States)

    Cho, Eikhyun; Park, Gwanwoo; Lee, Jae-Wan; Cho, Sung-Min; Kim, Taekyung; Kim, Joongeok; Choi, Wonjoon; Ohm, Won-Suk; Kang, Shinill

    2016-03-01

    We report a method of fabricating backing blocks for ultrasonic imaging transducers, using alumina/epoxy composites. Backing blocks contain scatterers such as alumina particles interspersed in the epoxy matrix for the effective scattering and attenuation of ultrasound. Here, the surface integrity can be an issue, where the composite material may be damaged during machining because of differences in strength, hardness and brittleness of the hard alumina particles and the soft epoxy matrix. Poor surface integrity results in the formation of air cavities between the backing block and the piezoelectric element upon assembly, hence the increased reflection off the backing block and the eventual degradation in image quality. Furthermore, with an issue of poor surface integrity due to machining, it is difficult to increase alumina as scatterers more than a specific mass fraction ratio. In this study, we increased the portion of alumina within epoxy matrix by obtaining an enhanced surface integrity using a net shape fabrication method, and verified that this method could allow us to achieve higher ultrasonic attenuation. Backing blocks were net-shaped with various mass fractions of alumina to characterize the formability and the mechanical properties, including hardness, surface roughness and the internal micro-structure, which were compared with those of machined backing blocks. The ultrasonic attenuation property of the backing blocks was also measured.

  16. PREPARATION AND TESTING OF CORROSIONAND SPALLATION-RESISTANT COATINGS

    Energy Technology Data Exchange (ETDEWEB)

    Hurley, John

    2014-11-01

    has been entered into a finite element model using ANSYS so that appropriate force-applying structures can be designed for use in joining structures composed of APMT and the nickel alloys. Finite element modeling has been performed to finalize the fabrication geometry for the corrosion-testing phase. The addition of another bolt increases stress uniformity away from the region where the clamping is applied. It appears that a bolt spacing of approximately 25 mm in each jig is appropriate. This will allow the fabrication of 50-mm-wide sections of joints for the corrosion-testing task. Gasifier sampling activities continue to determine what types of trace contaminants may occur in cleaned syngas that could lead to corrosion or deposition in turbines firing coal syngas. The EERC has several pilot-scale gasifiers that are continually used in a variety of test configurations as determined by the needs of the projects that are funding the tests. We are sampling both noncombusted and combusted syngas produced during some of the pilot-scale gasifier tests. This year sampling was performed of both syngas and combusted syngas while the entrained-flow gasifier (EFG) was firing subbituminous coal from the Antelope Mine in Wyoming. Results of scanning electron microscope analyses of the syngas before combustion showed no submicron particles, only flakes of iron oxide that had likely formed on steel surfaces inside the combustor. As shown in the 2013 annual report, soot was also collected from the syngas when the much-lower-temperature fluid-bed gasifier (FBG) was fired, indicating that the much higher temperature of the EFG prevented soot formation. However, particles collected from the combusted syngas consist almost entirely of submicron soot, and little to no vaporized metals made it past the warm-gas filters and scrubbers in the high-temperature EFG system which could then deposit in a turbine system burning a higher hydrogen syngas. These results are consistent with the

  17. Nanoparticle assisted coagulation of aqueous alumina suspensions

    Directory of Open Access Journals (Sweden)

    Abdullah Fatih Çetinel

    2012-02-01

    Full Text Available Colloidal processing of ceramics offers a high potential to achieve homogeneous microstructures with improved material properties. In this study, a novel forming method is investigated, which was already applied successfully for the fabrication of ceramic matrix composites (CMC, but is also considered to be a suitable direct casting technique for the fabrication of advanced ceramics with tailored microstructure and properties. The so-called nanoparticle assisted coagulation method (NPAC represents a modification of the hydrolysis-assisted solidification (HAS technique. It promises green components with high green strength, uniform density as well as homogeneous and tailored microstructure. Electrostatically stabilized colloidal suspensions with high solid loadings were produced by dispersing various fractions of submicron alumina powder and aluminium hydroxide nano-powder in water without use of any organic binder. Rheology and coagulation kinetics of suspensions and green part properties were studied regarding to modifications of pH value, setting temperature, amount of setting agent, amount of nano-powder, solids loading and process parameters like ultrasound treatment. It could be revealed that the homogeneous core-shell arrangement of submicron and nanoparticles in the colloidal state can be transmitted to the green state, which improves the microstructure and green density of the green parts. For this, the NPAC method is seen as a promising technique for the fabrication of advanced ceramics with tailored microstructure and properties.

  18. Mechanical properties of alumina porcelain during heating

    Science.gov (United States)

    Šín, Peter; Podoba, Rudolf; ŠtubÅa, Igor; Trník, Anton

    2014-11-01

    The mechanical strength and Young's modulus of green alumina porcelain (50 wt. % of kaolin, 25 wt. % of Al2O3, and 25 wt. % of feldspar) were measured during heating up to 900 °C and 1100 °C, respectively. To this end, we used the three point-bending method and modulated force thermomechanical analysis (mf-TMA). The loss liberation - of the physically bound water (20 - 250 °C) strengthens the sample and Young's modulus increases its values significantly. The dehydroxylation that takes place in the range of 400 - 650 °C causes a slight decrease in Young's modulus. On the other hand, the mechanical strength slightly increases in this temperature range, although it has a sudden drop at 420 °C. Beyond the dehydroxylation range, above 650 °C, both Young's modulus and mechanical strength increase. Above 950 °C, a sharp increase of Young's modulus is caused by the solid-state sintering and the new structure created by the high-temperature reactions in metakaolinite.

  19. Pressure and stress waves in a spallation neutron source mercury target generated by high-power proton pulses

    CERN Document Server

    Futakawa, M; Conrad, H; Stechemesser, H

    2000-01-01

    The international ASTE collaboration has performed a first series of measurements on a spallation neutron source target at the Alternating Gradient Synchrotron (AGS) in Brookhaven. The dynamic response of a liquid mercury target hit by high-power proton pulses of about 40 ns duration has been measured by a laser Doppler technique and compared with finite elements calculations using the ABAQUS code. It is shown that the calculation can describe the experimental results for at least the time interval up to 100 mu s after the pulse injection. Furthermore, it has been observed that piezoelectric pressure transducers cannot be applied in the high gamma-radiation field of a spallation target.

  20. Quantum molecular dynamics approach to estimate spallation yield from + 208Pb reaction at 800 MeV

    Indian Academy of Sciences (India)

    P K Sarkar; Maitreyee Nandy

    2003-10-01

    The spallation yield of neutrons and other mass fragments produced in 800 MeV proton induced reaction on 208Pb have been calculated in the framework of quantum molecular dynamics (QMD) model. The energy spectra and angular distribution have been calculated. Also, multiplicity distributions of the emitted neutrons and kinetic energy carried away by them have been estimated and compared with the available experimental data. The agreement is satisfactory. A major contribution to the neutron emission comes from statistical decay of the fragments. For mass and charge distributions of spallation productsthe QMD process gives rise to target-like and projectile-like fragments only.

  1. Neutron time-of-flight spectrometer based on HIRFL for studies of spallation reactions related to ADS project

    Institute of Scientific and Technical Information of China (English)

    张苏雅拉吐; 罗飞; 陈志强; 韩瑞; 刘星泉; 林炜平; 刘建立; 石福栋; 任培培; 田国玉

    2015-01-01

    A Neutron Time-of-Flight (NTOF) spectrometer, based at the Heavy Ion Research Facility in Lanzhou (HIRFL) was developed for studies of neutron production of proton induced spallation reactions related to the ADS project. After the presentation of comparisons between calculated spallation neutron production double-differential cross sections and the available experimental data, a detailed description of the NTOF spectrometer is given. Test beam results show that the spectrometer works well and data analysis procedures are established. The comparisons of the test beam neutron spectra with those of GEANT4 simulations are presented.

  2. Proceedings of the workshop on ion source issues relevant to a pulsed spallation neutron source: Part 2 workshop presentations

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, L.; Leung, Ka-Ngo; Alonso, J. [eds.

    1994-10-01

    As part of the Lawrence Berkeley Laboratory Pulsed Spallation Source study, this Workshop was convened to address ion-source technology`s present status with respect to the next-generation Pulsed Spallation Source in the 1-5 MW range for the neutron scattering community. Considerations of Low Energy Beam Transport (LEBT) parameters and designs were included in the discussions throughout the Workshop. Ion-source requirements and actually-achieved performances were assessed, resulting in a determination of research and development requirements to bridge the gap. Part 1 of these Proceedings summarizes the Workshop; Part 2 contains viewgraphs of Workshop presentations.

  3. Alumina-on-alumina total hip replacement for femoral neck fracture in healthy patients

    Directory of Open Access Journals (Sweden)

    Moretti Lorenzo

    2011-02-01

    Full Text Available Abstract Background Total hip replacement is considered the best option for treatment of displaced intracapsular fractures of the femoral neck (FFN. The size of the femoral head is an important factor that influences the outcome of a total hip arthroplasty (THA: implants with a 28 mm femoral head are more prone to dislocate than implants with a 32 mm head. Obviously, a large head coupled to a polyethylene inlay can lead to more wear, osteolysis and failure of the implant. Ceramic induces less friction and minimal wear even with larger heads. Methods A total of 35 THAs were performed for displaced intracapsular FFN, using a 32 mm alumina-alumina coupling. Results At a mean follow-up of 80 months, 33 have been clinically and radiologically reviewed. None of the implants needed revision for any reason, none of the cups were considered to have failed, no dislocations nor breakage of the ceramic components were recorded. One anatomic cementless stem was radiologically loose. Conclusions On the basis of our experience, we suggest that ceramic-on-ceramic coupling offers minimal friction and wear even with large heads.

  4. Towards the construction of the European spallation source – The Scandinavian experience

    Indian Academy of Sciences (India)

    C J Carlile; C Vettier; P Carlsson

    2008-11-01

    The possible realization of the European spallation source has been a long and winding story. However, thanks to the conjunction of a number of events it now looks highly probable that in 2008 there will indeed be a decision on the site and on a funding partnership of European countries who will together build and operate this long-pulse spallation neutron source. Currently there is a reference design comprising of a 632 m long proton accelerator which will deliver 2 ms pulses of protons to a liquid metal target with 22 instruments receiving thermal and cold neutron beams and providing unprecedented data rates. Lund is one of the two consortia competing to build the ESS – the ESS Scandinavia and a Hungarian–Spanish collaboration which is currently deciding on its preferred site. The Lund experience is one which highlights the many delicate steps which must be taken in order to get close to such decisions in a Europe of 30 plus nations. Of particular interest is the Energy Management Strategy which ESS Scandinavia would implement if Lund were to be the eventual chosen site. This will be set into the context of the political iniatives to mitigate the effects of global warming.

  5. Surface Laser Scanning Measurements for the n_TOF spallation target

    CERN Document Server

    Vlachoudis, V; Cennini, P; Lebbos, E; Lettry, J

    2010-01-01

    The n_TOF spallation target is made of pure lead immersed into cooling water. The target was operating normally from 2001 until august 2004, when an increased transfer of radioactive products from the spallation target to the cooling circuit has been observed. The target was considered damaged by the safety commission (SC/RP), and an investigation campaign started to verify the actual status of the target. According to FLUKA and Ansys calculations the target was working in the elastoplastic regime of the lead material, therefore a deformation might be expected. The present paper describes a laser photographic method and the results of a possible such deformation. The target had a surface activity of the order of 20 mSv/h, therefore we were forced to perform the measurement from distance. The used method, is based on a linelaser and a high resolution digital camera for retrieving the 3D position of the surface of the lead target. Similar methods are used in the film industry and animation studios for scanning ...

  6. Monte Carlo Modeling of Minor Actinide Burning in Fissile Spallation Targets

    Science.gov (United States)

    Malyshkin, Yury; Pshenichnov, Igor; Mishustin, Igor; Greiner, Walter

    2014-06-01

    Minor actinides (MA) present a harmful part of spent nuclear fuel due to their long half-lives and high radio-toxicity. Neutrons produced in spallation targets of Accelerator Driven Systems (ADS) can be used to transmute and burn MA. Non-fissile targets are commonly considered in ADS design. However, additional neutrons from fission reactions can be used in targets made of fissile materials. We developed a Geant4-based code MCADS (Monte Carlo model for Accelerator Driven Systems) for simulating neutron production and transport in different spallation targets. MCADS is suitable for calculating spatial distributions of neutron flux and energy deposition, neutron multiplication factors and other characteristics of produced neutrons and residual nuclei. Several modifications of the Geant4 source code described in this work were made in order to simulate targets containing MA. Results of MCADS simulations are reported for several cylindrical targets made of U+Am, Am or Am2O3 including more complicated design options with a neutron booster and a reflector. Estimations of Am burning rates are given for the considered cases.

  7. A neutron booster for spallation sources--application to accelerator driven systems and isotope production

    CERN Document Server

    Galy, J; Van Dam, H; Valko, J

    2002-01-01

    One can design a critical system with fissile material in the form of a thin layer on the inner surface of a cylindrical neutron moderator such as graphite or beryllium. Recently, we have investigated the properties of critical and near critical systems based on the use of thin actinide layers of uranium, plutonium and americium. The thickness of the required fissile layer depends on the type of fissile material, its concentration in the layer and on the geometrical arrangement, but is typically in the mu m-mm range. The resulting total mass of fissile material can be as low as 100 g. Thin fissile layers have a variety of applications in nuclear technology--for example in the design neutron amplifiers for medical applications and 'fast' islands in thermal reactors for waste incineration. In the present paper, we investigate the properties of a neutron booster unit for spallation sources and isotope production. In those applications a layer of fissile material surrounds the spallation source. Such a module cou...

  8. Spallation radiation damage and dosimetry for accelerator transmutation of waste applications

    Energy Technology Data Exchange (ETDEWEB)

    Wechsler, M.S.; Lin, C. [North Carolina State Univ., Raleigh, NC (United States). Dept. of Nuclear Engineering; Ferguson, P.D. [Missouri Univ., Rolla, MO (United States). Dept. of Nuclear Engineering; Sommer, W.F. [Los Alamos National Lab., NM (United States)

    1993-10-01

    Proposals are currently being made for systems to treat radioactive waste based on the use of accelerator-driven neutron sources. A linear proton accelerator with energies as high as 1600 MeV and currents up to 250 ma are anticipated for the driver. The neutron fluxes may reach up to 10{sup 20} neutrons/m{sup 2}s as generated by the spallation reactions that occur when the protons strike target materials. Calculations are described to determine radiation fluxes and flux spectra inherent in such systems and to estimate likely radiation effects on system components. The calculations use LAHET, a Monte Carlo high-energy transport code, and MCNP, a generalized-geometry, coupled neutron-photon Monte Carlo transport code. Cross sections for displacement and helium production are presented for spallation neutrons of energies from 21 MeV to 1600 MeV for Inconel 718 (Ni plus 18.5, 18.5, 5.1, and 3 wt % of Cr, Fe, Nb, and Mo, respectively), an alloy that is used for the proton beam entry window in several accelerators. In addition, results for this alloy are presented for the primary knocked-on atom (PKA) spectrum and the transmutation yield for 1600 MeV incident neutrons.

  9. Assessment of the neutron cross section database for mercury for the ORNL spallation source

    Energy Technology Data Exchange (ETDEWEB)

    Leal, L.C.; Spencer, R.R.; Ingersoll, D.T.; Gabriel, T.A. [Oak Ridge National Lab., TN (United States)

    1996-06-01

    Neutron source generation based on a high energy particle accelerator has been considered as an alternative to the canceled Advanced Neutron Source project at Oak Ridge National Laboratory. The proposed technique consists of a spallation neutron source in which neutrons are produced via the interaction of high-energy charged particles in a heavy metal target. Preliminary studies indicate that liquid mercury bombarded with GeV protons provides an excellent neutron source. Accordingly, a survey has been made of the available neutron cross-section data. Since it is expected that spectral modifiers, specifically moderators, will also be incorporated into the source design, the survey included thermal energy, resonance region, and high energy data. It was found that data of individual isotopes were almost non-existent and that the only evaluation found for the natural element had regions of missing data or discrepant data. Therefore, it appears that to achieve the desired degree of accuracy in the spallation source design it is necessary to re-evaluate the mercury database including making new measurements. During the presentation the currently available data will be presented and experiments proposed which can lead to design quality cross sections.

  10. Waste heat recovery from the European Spallation Source cryogenic helium plants - implications for system design

    Science.gov (United States)

    Jurns, John M.; Bäck, Harald; Gierow, Martin

    2014-01-01

    The European Spallation Source (ESS) neutron spallation project currently being designed will be built outside of Lund, Sweden. The ESS design includes three helium cryoplants, providing cryogenic cooling for the proton accelerator superconducting cavities, the target neutron source, and for the ESS instrument suite. In total, the cryoplants consume approximately 7 MW of electrical power, and will produce approximately 36 kW of refrigeration at temperatures ranging from 2-16 K. Most of the power consumed by the cryoplants ends up as waste heat, which must be rejected. One hallmark of the ESS design is the goal to recycle waste heat from ESS to the city of Lund district heating system. The design of the cooling system must optimize the delivery of waste heat from ESS to the district heating system and also assure the efficient operation of ESS systems. This report outlines the cooling scheme for the ESS cryoplants, and examines the effect of the cooling system design on cryoplant design, availability and operation.

  11. Study of the Production of Radioactive Isotopes through Cosmic Muon Spallation in KamLAND

    Energy Technology Data Exchange (ETDEWEB)

    KamLAND Collaboration; Abe, S.; Enomoto, S.; Furuno, K.; Gando, Y.; Ikeda, H.; Inoue, K.; Kibe, Y.; Kishimoto, Y.; Koga, M.; Minekawa, Y.; Mitsui, T.; Nakajima, K.; Nakajima, K.; Nakamura, K.; Nakamura, M.; Shimizu, I.; Shimizu, Y.; Shirai, J.; Suekane, F.; Suzuki, A.; Takemoto, Y.; Tamae, K.; Terashima, A.; Watanabe, H.; Yonezawa, E.; Yoshida, S.; Kozlov, A.; Murayama, H.; Busenitz, J.; Classen, T.; Grant, C.; Keefer, G.; Leonard, D. S.; McKee, D.; Piepke, A.; Banks, T. I.; Bloxham, T.; Detwiler, J. A.; Freedman, S. J.; Fujikawa, B. K.; Gray, F.; Guardincerri, E.; Hsu, L.; Ichimura, K.; Kadel, R.; Lendvai, C.; Luk, K.-B.; O' Donnell, T.; Steiner, H. M.; Winslow, L. A.; Dwyer, D. A.; Jillings, C.; Mauger, C.; McKeown, R. D.; Vogel, P.; Zhang, C.; Berger, B. E.; Lane, C. E.; Maricic, J.; Miletic, T.; Batygov, M.; Learned, J. G.; Matsuno, S.; Pakvasa, S.; Foster, J.; Horton-Smith, G. A.; Tang, A.; Dazeley, S.; Downum, K. E.; Gratta, G.; Tolich, K.; Bugg, W.; Efremenko, Y.; Kamyshkov, Y.; Perevozchikov, O.; Karwowski, H. J.; Markoff, D. M.; Tornow, W.; Heeger, K. M.; Piquemal, F.; Ricol, J.-S.; Decowski, M. P.

    2009-06-30

    Radioactive isotopes produced through cosmic muon spallation are a background for rare event detection in {nu} detectors, double-beta-decay experiments, and dark-matter searches. Understanding the nature of cosmogenic backgrounds is particularly important for future experiments aiming to determine the pep and CNO solar neutrino fluxes, for which the background is dominated by the spallation production of {sup 11}C. Data from the Kamioka Liquid scintillator Anti-Neutrino Detector (KamLAND) provides valuable information for better understanding these backgrounds, especially in liquid scintillator, and for checking estimates from current simulations based upon MUSIC, FLUKA, and Geant4. Using the time correlation between detected muons and neutron captures, the neutron production yield in the KamLAND liquid scintillator is measured to be (2.8 {+-} 0.3) x 10{sup -4} n/({mu} {center_dot} (g/cm{sup 2})). For other isotopes, the production yield is determined from the observed time correlation related to known isotope lifetimes. We find some yields are inconsistent with extrapolations based on an accelerator muon beam experiment.

  12. MEGAPIE, a 1 MW pilot experiment for a liquid metal spallation target

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, G.S. [Paul Scherrer Institut, Spallation Neutron Source Division, Villigen-PSI (Switzerland); Salvatores, M. [CEA Cadarache, Direction des Reacteurs Nucleaires, Saint-Paul-lez-Durance Cedex (France); Heusener, G. [Forschungszentrum Karlsruhe, Projekt Nukleare Sicherheitsforschung, Karlsruhe (Germany)

    2001-03-01

    MEGAPIE (Megawatt Pilot Target Experiment) is an initiative launched by Commissariat a l'Energie Atomique, Cadarache (France) and Forschungszentrum Karlsruhe (Germany) in collaboration with Paul Scherrer Institut (Switzerland), to demonstrate, in an international collaboration, the feasibility of a liquid lead bismuth target for spallation facilities at a beam power level of 1 MW. Such a target is under consideration for various concepts of accelerator driven systems (ADS) to be used in transmutation of nuclear waste and other applications world-wide. It also has the potential of increasing significantly the thermal neutron flux available at the spallation neutron source (SINQ) for neutron scattering. SINQ's beam power being close to 1 MW already, this facility offers a unique opportunity to realize such an experiment with a reasonably small number of new ancillary systems. The paper describes the basic features of the experiment and its boundary conditions, the technical concept of the target and underlying research carried out at participating laboratories. (author)

  13. GEANT4 simulations of the n{sub T}OF spallation source and their benchmarking

    Energy Technology Data Exchange (ETDEWEB)

    Lo Meo, S. [Research Centre ' ' Ezio Clementel' ' , ENEA, Bologna (Italy); Section of Bologna, INFN, Bologna (Italy); Cortes-Giraldo, M.A.; Lerendegui-Marco, J.; Guerrero, C.; Quesada, J.M. [Universidad de Sevilla, Facultad de Fisica, Sevilla (Spain); Massimi, C.; Vannini, G. [Section of Bologna, INFN, Bologna (Italy); University of Bologna, Physics and Astronomy Dept. ' ' Alma Mater Studiorum' ' , Bologna (Italy); Barbagallo, M.; Colonna, N. [INFN, Section of Bari, Bari (Italy); Mancusi, D. [CEA-Saclay, DEN, DM2S, SERMA, LTSD, Gif-sur-Yvette CEDEX (France); Mingrone, F. [Section of Bologna, INFN, Bologna (Italy); Sabate-Gilarte, M. [Universidad de Sevilla, Facultad de Fisica, Sevilla (Spain); European Organization for Nuclear Research (CERN), Geneva (Switzerland); Vlachoudis, V. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Collaboration: The n_TOF Collaboration

    2015-12-15

    Neutron production and transport in the spallation target of the n{sub T}OF facility at CERN has been simulated with GEANT4. The results obtained with different models of high-energy nucleon-nucleus interaction have been compared with the measured characteristics of the neutron beam, in particular the flux and its dependence on neutron energy, measured in the first experimental area. The best agreement at present, within 20% for the absolute value of the flux, and within few percent for the energy dependence in the whole energy range from thermal to 1 GeV, is obtained with the INCL++ model coupled with the GEANT4 native de-excitation model. All other available models overestimate by a larger factor, of up to 70%, the n{sub T}OF neutron flux. The simulations are also able to accurately reproduce the neutron beam energy resolution function, which is essentially determined by the moderation time inside the target/moderator assembly. The results here reported provide confidence on the use of GEANT4 for simulations of spallation neutron sources. (orig.)

  14. Electrostatic levitation facility optimized for neutron diffraction studies of high temperature liquids at a spallation neutron source

    Science.gov (United States)

    Mauro, N. A.; Vogt, A. J.; Derendorf, K. S.; Johnson, M. L.; Rustan, G. E.; Quirinale, D. G.; Kreyssig, A.; Lokshin, K. A.; Neuefeind, J. C.; An, Ke; Wang, Xun-Li; Goldman, A. I.; Egami, T.; Kelton, K. F.

    2016-01-01

    Neutron diffraction studies of metallic liquids provide valuable information about inherent topological and chemical ordering on multiple length scales as well as insight into dynamical processes at the level of a few atoms. However, there exist very few facilities in the world that allow such studies to be made of reactive metallic liquids in a containerless environment, and these are designed for use at reactor-based neutron sources. We present an electrostatic levitation facility, NESL (for Neutron ElectroStatic Levitator), which takes advantage of the enhanced capabilities and increased neutron flux available at spallation neutron sources (SNSs). NESL enables high quality elastic and inelastic neutron scattering experiments to be made of reactive metallic and other liquids in the equilibrium and supercooled temperature regime. The apparatus is comprised of a high vacuum chamber, external and internal neutron collimation optics, and a sample exchange mechanism that allows up to 30 samples to be processed between chamber openings. Two heating lasers allow excellent sample temperature homogeneity, even for samples approaching 500 mg, and an automated temperature control system allows isothermal measurements to be conducted for times approaching 2 h in the liquid state, with variations in the average sample temperature of less than 0.5%. To demonstrate the capabilities of the facility for elastic scattering studies of liquids, a high quality total structure factor for Zr64Ni36 measured slightly above the liquidus temperature is presented from experiments conducted on the nanoscale-ordered materials diffractometer (NOMAD) beam line at the SNS after only 30 min of acquisition time for a small sample (˜100 mg).

  15. Electrostatic levitation facility optimized for neutron diffraction studies of high temperature liquids at a spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Mauro, N. A., E-mail: namauro@noctrl.edu [Department of Physics, North Central College, Naperville, Illinois 60540 (United States); Vogt, A. J. [Instrument and Source Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Derendorf, K. S. [Mechanical Engineering and Materials Science, Washington University, St. Louis, Missouri 63130 (United States); Johnson, M. L.; Kelton, K. F. [Department of Physics and Institute of Materials Science and Engineering, Washington University, 1 Brookings Drive, St. Louis, Missouri 63130 (United States); Rustan, G. E.; Quirinale, D. G.; Goldman, A. I. [Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States); Kreyssig, A. [Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States); Division of Materials Sciences and Engineering, Ames Laboratory, Ames, Iowa 50011 (United States); Lokshin, K. A. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States); Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Neuefeind, J. C.; An, Ke [Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Wang, Xun-Li [Department of Physics and Materials Science, City University of Hong Kong, 83 Tat Chee Ave., Kowloon (Hong Kong); Egami, T. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States); Department of Physics and Astronomy, Joint Institute for Neutron Sciences, University of Tennessee, Knoxville, Tennessee 37996 (United States)

    2016-01-15

    Neutron diffraction studies of metallic liquids provide valuable information about inherent topological and chemical ordering on multiple length scales as well as insight into dynamical processes at the level of a few atoms. However, there exist very few facilities in the world that allow such studies to be made of reactive metallic liquids in a containerless environment, and these are designed for use at reactor-based neutron sources. We present an electrostatic levitation facility, NESL (for Neutron ElectroStatic Levitator), which takes advantage of the enhanced capabilities and increased neutron flux available at spallation neutron sources (SNSs). NESL enables high quality elastic and inelastic neutron scattering experiments to be made of reactive metallic and other liquids in the equilibrium and supercooled temperature regime. The apparatus is comprised of a high vacuum chamber, external and internal neutron collimation optics, and a sample exchange mechanism that allows up to 30 samples to be processed between chamber openings. Two heating lasers allow excellent sample temperature homogeneity, even for samples approaching 500 mg, and an automated temperature control system allows isothermal measurements to be conducted for times approaching 2 h in the liquid state, with variations in the average sample temperature of less than 0.5%. To demonstrate the capabilities of the facility for elastic scattering studies of liquids, a high quality total structure factor for Zr{sub 64}Ni{sub 36} measured slightly above the liquidus temperature is presented from experiments conducted on the nanoscale-ordered materials diffractometer (NOMAD) beam line at the SNS after only 30 min of acquisition time for a small sample (∼100 mg)

  16. Study of the spallation residues in the reaction Au (800 MeV/nucleon) + p; Etude des residus de spallation dans la reaction Au (800 MeV par nucleon) + p

    Energy Technology Data Exchange (ETDEWEB)

    Mustapha, Brahim [Inst. de Physique Nucleaire, Paris-11 Univ., 91 - Orsay (France)

    1999-09-09

    As a neutron source, the spallation reaction is of importance for different fields of research and for a possible hybrid reactor. The study of spallation residues, their cross sections and their energetic properties, is necessary for such applications and for a better understanding of this process. Several studies of spallation products were done using spectroscopic methods. Only radioactive nuclides were detected. Aiming at a more precise measurement, covering the whole range of spallation residues, this study was done using the reverse kinematics method. A liquid hydrogen target was irradiated by an 800 MeV/nucleon gold beam. The produced nuclei were detected in flight before any radioactive decay with about 10% precision. Independent cross section were then obtained. Velocity distributions were completely reconstructed. In their present forms, the theoretical calculations based upon the two-step model, 'intra-nuclear cascade' + 'evaporation', are unable to reproduce the whole set of experimental aspects. An inter-comparison using different INC/EVA combinations permitted to identify the more significant points in these calculations. The important behaviour of this codes were examined. Due to compensation effects between both steps, cascade and evaporation, this study did not lead to a definite conclusion. (author)

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

    Indian Academy of Sciences (India)

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

    2000-11-01

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

  18. Peltier heats in cryolite melts with alumina

    Energy Technology Data Exchange (ETDEWEB)

    Flem, B.E.; Ratkje, S.K.; Sterten, A. [Univ. of Trondheim (Norway)

    1996-10-01

    The Seebeck coefficient was measured for cells with electrolytes of molten mixtures of sodium fluoride and aluminum fluoride saturated with alumina. The electrodes were either a pair of oxygen electrodes or a pair of aluminum electrodes. For the molar ratio NaF/AlF{sub 3} equal to 1.8, 1.2 and 1.0, the authors obtained the Seebeck coefficients {minus}1.80 mV K{sup {minus}1} at 971 C, {minus}1.63 mV K{sup {minus}1} at 813.6 C and {minus}0.583 mV K{sup {minus}1} at 758 C, respectively, for the oxygen electrodes. For the aluminum electrodes, the authors obtained the Seebeck coefficient {minus}1.23 mV K{sup {minus}1} at 962 C, for the molar ratio NaF/AlF{sub 3} equal to 1.8. The results suggest that there is a substantial reversible heat consumption at the anode during aluminum electrolysis and a large reversible heat production at the cathode. The highest temperature in the Hall-Heroult cell is then closer to the cathode than the anode. The transported entropies of Al{sup 3+} and O{sup 2{minus}} were calculated to be 77 J mol{sup {minus}1} K{sup {minus}1} and 10 J mol{sup {minus}1} K{sup {minus}1}, respectively, when the molar ratio NaF/AlF{sub 3} was equal to 1.0.

  19. HEIMDAL: A thermal neutron powder diffractometer with high and flexible resolution combined with SANS and neutron imaging - Designed for materials science studies at the European Spallation Source

    Science.gov (United States)

    Holm, Sonja L.; Lefmann, Kim; Henry, Paul F.; Bertelsen, Mads; Schefer, Jürg; Christensen, Mogens

    2016-08-01

    HEIMDAL will be a multi length scale neutron scattering instrument for the study of structures covering almost nine orders of magnitude from 0.01 nm to 50 mm. The instrument is accepted for construction at the European Spallation Source (ESS) and features a variable resolution thermal neutron powder diffractometer (TNPD), combined with small angle neutron scattering (SANS) and neutron imaging (NI). The instrument uses a novel combination of a cold and a thermal guide to fulfill the diverse requirements for diffraction and SANS. With an instrument length of 170 m, HEIMDAL will take advantage of the high neutron flux of the long pulse at ESS, whilst maintaining a high q-resolution due to the long flight path. The q-range coverage is up to 20 Å-1 allowing low-resolution PDF analysis. With the addition of SANS, HEIMDAL will be able to cover a uniquely broad length scale within a single instrumental set-up. HEIMDAL will be able to accommodate modern materials research in a broad variety of fields, and the task of the instrument will be to study advanced functional materials in action, as in situ and in operandi at multiple length scales (0.01-100 nm) quasi simultaneously. The instrument combines state-of-the-art neutron scattering techniques (TNPD, SANS, and NI) with the goal of studying real materials, in real time, under real conditions. This article describes the instrument design ideas, calculations and results of simulations and virtual experiments.

  20. Pressureless sintering behavior of injection molded alumina ceramics

    Directory of Open Access Journals (Sweden)

    Liu W.

    2014-01-01

    Full Text Available The pressureless sintering behaviors of two widely used submicron alumina (MgOdoped and undoped with different solid loadings produced by injection molding have been studied systematically. Regardless of the sinterability of different powders depending on their inherent properties, solid loading plays a critical role on the sintering behavior of injection molded alumina, which greatly determines the densification and grain size, and leads to its full densification at low temperatures. As compared to the MgO-doped alumina powder, the undoped specimens exhibit a higher sinterability for its smaller particle size and larger surface area. While full densification could be achieved for MgO-doped powders with only a lower solid loading, due to the fact that MgO addition can reduce the detrimental effect of the large pore space on the pore-boundary separation.

  1. Origin of High-Alumina Basalt, Andesite, and Dacite Magmas.

    Science.gov (United States)

    Hamilton, W

    1964-10-30

    The typical volcanic rocks of most island arcs and eugeosynclines, and of some continental environments, are basalt, andesite, and dacite, of high alumina content. The high-alumina basalt differs from tholeiitic basalt primarily in having a greater content of the components of calcic plagioclase. Laboratory data indicate that in the upper mantle, below the level at which the basaltic component of mantle rock is transformed by pressure to eclogite or pyroxenite, the entire basaltic portion probably is melted within a narrow temperature range, but that above the level of that transformation plagioclase is melted selectively before pyroxene over a wide temperature range. The broad spectrum of high-alumina magmas may represent widely varying degrees of partial melting above the transformation level, whereas narrow-spectrum tholeiite magma may represent more complete melting beneath it.

  2. Fabrication of alumina films with laminated structures by ac anodization

    Directory of Open Access Journals (Sweden)

    Hiroyo Segawa

    2014-01-01

    Full Text Available Anodization techniques by alternating current (ac are introduced in this review. By using ac anodization, laminated alumina films are fabricated. Different types of alumina films consisting of 50–200 nm layers were obtained by varying both the ac power supply and the electrolyte. The total film thickness increased with an increase in the total charge transferred. The thickness of the individual layers increased with the ac voltage; however, the anodization time had little effect on the film thickness. The laminated alumina films resembled the nacre structure of shells, and the different morphologies exhibited by bivalves and spiral shells could be replicated by controlling the rate of increase of the applied potentials.

  3. Alumina Template-Dependant Growth of Cobalt Nanowire Arrays

    Directory of Open Access Journals (Sweden)

    L. Malferrari

    2009-01-01

    Full Text Available Different electrochemical regimes and porous alumina were applied for template synthesis of cobalt nanowire (nw arrays, revealing several peculiar cases. In contrast to quite uniform filling of sulfuric acid alumina templates by alternating current deposition, nonuniform growth of the Co nw tufts and mushrooms was obtained for the case of oxalic acid templates. We showed herein for the first time that such configurations arise from the spontaneous growth of cobalt nw groups evolving from the cobalt balls at the Al/alumina interface. Nevertheless, the uniform growth of densely packed cobalt nw arrays, up to tens of micrometers in length, was obtained via long-term direct current galvanostatic deposition at low current density using oxalic acid templates one-side coated by conducting layer. The unique point of this regime is the formation of hexagonal lattice Co nws with a preferred (100 growth direction.

  4. Porous Alumina as a Promising Biomaterial for Public Health.

    Science.gov (United States)

    Bragazzi, Nicola Luigi; Gasparini, Roberto; Amicizia, Daniela; Panatto, Donatella; Larosa, Claudio

    2015-01-01

    Porous aluminum is a nanostructured material characterized by unique properties, such as chemical stability, regular uniformity, dense hexagonal porous lattice with high aspect ratio nanopores, excellent mechanical strength, and biocompatibility. This overview examines how the structure and properties of porous alumina can be exploited in the field of public health. Porous alumina can be employed for fabricating membranes and filters for bioremediation, water ultrafiltration, and microfiltration/nanofiltration, being a promising technique for having clean and fresh water, which is essential for human health. Porous alumina-based nanobiosensor coated with specific antibodies or peptides seem to be a useful tool to detect and remove pathogens both in food and in water, as well as for environmental monitoring. Further, these applications, being low-energy demanding and cost-effective, are particularly valuable in resource-limited settings and contexts, and can be employed as point of use devices in developing countries, where there is an urgent need of hygiene and safety assurance.

  5. Effect of different sources of alumina on the microstructure and mechanical properties of the triaxial porcelain

    OpenAIRE

    Gralik,G.; Chinelattot,A. L.; A. S. A. Chinelatto

    2014-01-01

    Porcelains composed of kaolin-quartz-feldspar are called triaxial porcelains. The use of alumina as a substitute for quartz in porcelains has been developed for some time. The results show a significant improvement in their mechanical properties, but alumina has a high cost. The possibility of using alternative materials as a source of alumina with lower cost was investigated. In this work, alternative raw materials were used as a source of alumina: refractory bauxite, primary aluminum hydrox...

  6. Factors contributing to the breakdown of sodium beta-alumina

    Energy Technology Data Exchange (ETDEWEB)

    Buechele, A.C.

    1982-05-01

    Clarification of the breakdown process occurring during charge transfer in sodium beta alumina solid electrolytes was derived from: (1) studying the effects of molten sodium contact at 350/sup 0/C on single crystal sodium beta alumina and polycrystalline sodium beta alumina; (2) determination of critical current density by monitoring acoustic emissions accompanying crack growth in sodium/sodium beta alumina/sodium cells subjected to linear current ramping at 1 mA cm/sup -2/ sec/sup -1/; (3) failure analysis conducted on cycled electrolytes, some from commercial sodium/sulfur cells, which had been subjected to up to 703 Ahr cm/sup -2/ of charge transfer. Gray coloration developing in beta aluminas in contact with molten sodium was found to be a consequence of formation, through reduction by sodium, of oxygen vacancies charge compensated by electrons. Electronic conductivity of the electrolyte increases as a result. No second phase formation was detected. Colored electrolytes from sodium/sulfur cells show evidence of a newly recognized degradation mechanism in which fracture occurs when sodium is reduced and deposited internally under pressure as metal in regions where an electronic conductivity gradient exists. Heating colored beta aluminas in air produces reoxidation and bleaching. Kinetics and other properties of the coloration and bleaching processes were determined. Critical current density was found to bear an inverse relation to average electrolyte grain size. Evidence was found in the cycled electrolytes for a slow crack growth mechanism and a progressive mode of degradation advancing from the sulfur electrode interface. Implications of the findings for the construction and operation of sodium/sulfur battery systems are discussed.

  7. CRACK PROPAGATION BEHAVIOR AND LIFETIME PREDICTION IN ALUMINA AND ZIRCONIA

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The lifetime prediction of ceramics is discussed on the basis of the relationship between stress intensity factor KI and crack velocity v. The effects of water environment, the cyclic loading and microstructure of material on KI-v characteristics are studied by carrying out the crack growth tests by the double torsion (DT) method under the static and cyclic loading in both environments of air and water for alumina and zirconia. KI-v characteristics determined by the double torsion method are used to predict time-to-failure under the cyclic loading of alumina and zirconia ceramics. The predictions agree qualitatively with the experimental results.

  8. Controllable synthesis and characterization of alumina/MWNT nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Nemeth, Zoltan; Hernadi, Klara [Department of Applied and Environmental Chemistry, University of Szeged, Rerrich Bela ter 1, 6720 Szeged (Hungary); Marko, Kata; Erdohelyi, Andras [Department of Physical Chemistry and Material Science, University of Szeged, Aradi ter 2, 6720 Szeged (Hungary); Forro, Laszlo [Laboratory of Physics of Complex Matter, IPMC, EPFL, 1026 Ecublens (Switzerland)

    2011-11-15

    The aim of this work is to develop a controllable synthesis pathway which produces a stable alumina layer on the surface of carbon nanotubes by impregnation method. Precursor compounds such as aluminium isopropoxide and aluminium-acetyl-acetonate were used to cover the surface of multiwalled carbon nanotubes (MWNTs) under different solvent conditions. As-prepared alumina coverages were characterized by TEM, SEM, SEM-EDX, TG and X-ray diffraction techniques. Results revealed that homogeneous coverage can be achieved in a controllable way. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Cylindrical Three-Dimensional Porous Anodic Alumina Networks

    Directory of Open Access Journals (Sweden)

    Pedro M. Resende

    2016-11-01

    Full Text Available The synthesis of a conformal three-dimensional nanostructure based on porous anodic alumina with transversal nanopores on wires is herein presented. The resulting three-dimensional network exhibits the same nanostructure as that obtained on planar geometries, but with a macroscopic cylindrical geometry. The morphological analysis of the nanostructure revealed the effects of the initial defects on the aluminum surface and the mechanical strains on the integrity of the three-dimensional network. The results evidence the feasibility of obtaining 3D porous anodic alumina on non-planar aluminum substrates.

  10. Mechanical properties of tricalcium phosphate-alumina composites

    Science.gov (United States)

    Sakka, S.; Ben Ayed, F.; Bouaziz, J.

    2012-02-01

    Tricalcium phosphate and alumina powder were mixed in order to elaborate biphasic ceramics composites. This study deals to produce bioceramics composites sintered at various temperatures for differents times. The characterization of samples, before and after the sintering process was investigated, using X-Ray diffraction, scanning electronic microscopy, 31P and 27Al nuclear magnetic resonance and differential thermal analysis. Mechanical properties of biphasic composites were studied using Brazilian test. The tricalcium phosphate - 75 wt% alumina composites mechanical resistance increased with sintered temperature. The mechanical resistance reach it's optimum value (8.6 MPa) at 1550°C for two hours.

  11. Effect of Filler Composition on the Brazing of Alumina to Copper Using Ultrasonic Wave

    Institute of Scientific and Technical Information of China (English)

    Khalid M. HAFEZ; Masaaki NAKA

    2003-01-01

    An ultrasonic wave was applied during brazing of alumina to Cu. First alumina was metallized by applying ultrasonicwave in braze bath. Then the metallized alumina was brazed with Cu using the same filler alloy. The filler used wereZn-Al alloys and Zn-Sn A

  12. THE COMMISSIONING PLAN FOR THE SPALLATION NEUTRON SOURCE RING AND TRANSPORT LINES.

    Energy Technology Data Exchange (ETDEWEB)

    RAPARIA,D.BLASKIEWICZ,M.LEE,Y.Y.WEI,J.ET AL.

    2004-03-10

    The Spallation Neutron Source (SNS) accelerator systems will provide a 1 GeV, 1.44 MW proton beam to a liquid mercury target for neutron production. In order to satisfy the accelerator systems' portion of the Critical Decision 4 (CD-4) commissioning goal (which marks the completion of the construction phase of the project), a beam pulse with intensity greater than 1 x 10{sup 13} protons must be accumulated in the ring, extracted in a single turn and delivered to the target. A commissioning plan has been formulated for bringing into operation and establishing nominal operating conditions for the various ring and transport line subsystems as well as for establishing beam conditions and parameters which meet the commissioning goal.

  13. Crossover from a fission-evaporation scenario towards multifragmentation in spallation reactions

    CERN Document Server

    Napolitani, P

    2006-01-01

    Mostly for the purpose of applications for the energy and the environment and for the design of sources of neutrons or exotic nuclides, intense research has been dedicated to spallation, induced by protons or light projectiles at incident energies of around 1 GeV. In this energy range, while multifragmentation has still a minor share in the total reaction cross section, it was observed to have, together with fission, a prominent role in the production and the kinematics of intermediate-mass fragments, so as to condition the whole production of light and heavy nuclides. The experimental observables we dispose of attribute rather elusive properties to the intermediate-mass fragments and do not allow to classify them within one exclusive picture which is either multifragmentation or fission. Indeed, these two decay mechanisms, driven by different kinds of instabilities, exhibit behaviours which are closely comparable. High-resolution measurements of the reaction kinematics trace the way for probing finer feature...

  14. A Spallation Model for 44Ti production in Core Collapse Supernovae

    CERN Document Server

    Ouyed, Amir; Leahy, Denis; Jaikumar, Prashanth

    2012-01-01

    Current cc-SN models predict overproduction of 44Ti compared to observations. We present a model for an alternative channel where a cc-SN explosion is followed by a neutron star detonation (Quark Nova or QN), resulting in a spallation reaction of SN ejecta that produces 44Ti. We can achieve a 44Ti production of ~ 10^-4 Msun with our model under the right time delay between the QN and the SN. Our model also produces unique signals not found in standard, cc-SN nucleosynthesis models. Some of these unique signals include a significantly large production of 7Be and 22Na. We discuss some of these signals by analyzing the late time light curve and gamma spectroscopy of our model.

  15. Computer simulations for rf design of a Spallation Neutron Source external antenna H ion source

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sung-Woo [ORNL; Goulding, Richard Howell [ORNL; Kang, Yoon W [ORNL; Shin, Ki [ORNL; Welton, Robert F [ORNL

    2010-01-01

    Electromagnetic modeling of the multicusp external antenna H ion source for the Spallation Neutron Source SNS has been performed in order to optimize high-power performance. During development of the SNS external antenna ion source, antenna failures due to high voltage and multicusp magnet holder rf heating concerns under stressful operating conditions led to rf characteristics analysis. In rf simulations, the plasma was modeled as an equivalent lossy metal by defining conductivity as . Insulation designs along with material selections such as ferrite and Teflon could be included in the computer simulations to compare antenna gap potentials, surface power dissipations, and input impedance at the operating frequencies, 2 and 13.56 MHz. Further modeling and design improvements are outlined in the conclusion.

  16. Optimized concept design of the target station of Chinese spallation neutron source

    Science.gov (United States)

    Yan, Q. W.; Yin, W.; Yu, B. L.

    2005-08-01

    CSNS (Chinese spallation neutron source) target station, with proton beam power of 100 kW, consists of Tungsten rectangular target surrounded by a beryllium/steel reflector, three wing-moderators and the shield having 18 beam tubes. The leakage neutron intensity from the target (with reflector) and heat deposition on the target, reflector and shield were calculated using Monte Carlo code NMTC/JAM respectively. It is reported that the target having rectangular section will produce more leakage neutron intensity than a square one for the same proton power. The temperature and thermal stress distribution in the target disks were calculated by the finite element method. The performances of moderators were calculated using MCNP-4A code.

  17. Low-Level RF Control of Spallation Neutron Source: System and Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Hengjie [ORNL

    2005-01-01

    The low-level RF control system currently commissioned throughout the Spallation Neutron Source (SNS) LINAC evolved from three design iterations over one year intensive research and development. Its digital hardware implementation is efficient, and has succeeded in achieving a minimum latency of less than 150 ns which is the key for accomplishing an all digital feedback control for the full bandwidth. The control bandwidth is analyzed in frequency domain and characterized by testing its transient response. The hardware implementation also includes the provision of a time-shared input channel for a superior phase differential measurement between the cavity field and the reference. A companion co-simulation system for the digital hardware was developed to ensure a reliable long-term supportability. A large effort has also been made in the operation software development for the practical issues such as the process automations, cavity filling, beam loading compensation, and the cavity mechanical resonance suppression.

  18. The Design Performance of the Integrated Spallation Neutron Source Vacuum Control System

    CERN Document Server

    Tang, Johnny Y; Ladd, Peter; Williams, Derrick

    2005-01-01

    The Spallation Neutron Source vacuum control systems have been developed within a collaboration of Lawrence Berkeley National Laboratory(LBNL), Los Alamos National Laboratory(LANL), Thomas Jefferson National Accelerator Facility(TJNAF), and Brookhaven National Laboratory(BNL). Each participating lab is responsible for a different section of the machine. Although a great deal of effort has been made to standardize vacuum instrumentation components and the global control system interfaces, the varied requirements of the different sections of the machine made horizontal integration of the individual vacuum control systems both interesting and challenging. To support commissioning, the SNS control system team and the vacuum group developed a set of test strategies and the interlock schemes that allowed horizontal vacuum system integration to be effectively achieved. The design of the vacuum control interlock scheme developed will be presented together with the results of performance measurements made on these sch...

  19. EXPERIENCE WITH COLLABORATIVE DEVELOPMENT FOR THE SPALLATION NEUTRON SOURCE FROM A PARTNER LAB PERSPECTIVE.

    Energy Technology Data Exchange (ETDEWEB)

    HOFF, L.T.

    2005-10-10

    Collaborative development and operation of large physics experiments is fairly common. Less common is the collaborative development or operation of accelerators. A current example of the latter is the Spallation Neutron Source (SNS). The SNS project was conceived as a collaborative effort between six DOE facilities. In the SNS case, the control system was also developed collaboratively. The SNS project has now moved beyond the collaborative development phase and into the phase where Oak Ridge National Lab (ORNL) is integrating contributions from collaborating ''partner labs'' and is beginning accelerator operations. In this paper, the author reflects on the benefits and drawbacks of the collaborative development of an accelerator control system as implemented for the SNS project from the perspective of a partner lab.

  20. XT-ADS Windowless spallation target thermohydraulic design and experimental setup

    Energy Technology Data Exchange (ETDEWEB)

    Class, A.G., E-mail: andreas.class@kit.edu [KIT, Kaiserstrasse 12, D-76131 Karlsruhe (Germany); Angeli, D. [AAA, Advanced Accelerator Applications, 20 Rue Diesel, 06130 Saint-Genis-Poully (France); Batta, A. [KIT, Kaiserstrasse 12, D-76131 Karlsruhe (Germany); Dierckx, M. [SCK-CEN, Boeretang 200, B-2400 Mol (Belgium); Fellmoser, F. [KIT, Kaiserstrasse 12, D-76131 Karlsruhe (Germany); Moreau, V. [CRS4, Polaris Edificio 1, 09010 Pula, CA (Italy); Roelofs, F. [NRG Petten, Westerduinweg 3, P.O. Box 25, NL-1755 ZG Petten (Netherlands); Schuurmans, P.; Van Tichelen, K. [SCK-CEN, Boeretang 200, B-2400 Mol (Belgium); Wetzel, T. [KIT, Kaiserstrasse 12, D-76131 Karlsruhe (Germany)

    2011-08-31

    The objective of the European 6th framework Integrated Project (IP) EUROTRANS (EUROpean Research Programme for the TRANSmutation of High Level Nuclear Waste in an Accelerator Driven System) is to demonstrate the feasibility of transmutation of high level nuclear waste using subcritical Accelerator Driven Systems (ADS). The spallation target represents the most challenging new component in an ADS since it is the component coupling the accelerator and the nuclear core and is subjected to very high thermal load in a high radiation field. In this document the thermal hydraulic activities which led to reliable design rules for a windowless target are presented and the status of the heavy liquid metal target mock-up experiment at the KArlsruhe Liquid metal LAboratory (KALLA) are reported.

  1. A spallation-based irradiation test facility for fusion and future fission materials

    CERN Document Server

    Samec, K; Kadi, Y; Luis, R; Romanets, Y; Behzad, M; Aleksan, R; Bousson, S

    2014-01-01

    The EU’s FP7 TIARA program for developing accelerator-based facilities has recently demonstrated the unique capabilities of a compact and powerful spallation source for irradiating advanced nuclear materials. The spectrum and intensity of the neutron flux produced in the proposed facility fulfils the requirements of the DEMO fusion reactor for ITER, ADS reactors and also Gen III / IV reactors. Test conditions can be modulated, covering temperature from 400 to 550°C, liquid metal corrosion, cyclical or static stress up to 500 MPa and neutron/proton irradiation damage of up to 25 DPA per annum. The entire “TMIF” facility fits inside a cube 2 metres on a side, and is dimensioned for an accelerator beam power of 100 kW, thus reducing costs and offering great versatility and flexibility.

  2. VSI@ESS: Case study for a vibrational spectroscopy instrument at the european spallation source

    Science.gov (United States)

    Zoppi, Marco; Fedrigo, Anna; Celli, Milva; Colognesi, Daniele

    2015-01-01

    Neutron Vibrational Spectroscopy is a well-established experimental technique where elementary excitations at relatively high frequency are detected via inelastic neutron scattering. This technique attracts a high interest in a large fraction of the scientific community in the fields of chemistry, materials science, physics, and biology, since one of its main applications exploits the large incoherent scattering cross section of the proton with respect to all the other elements, whose dynamics can be spectroscopically detected, even if dissolved in very low concentration in materials composed of much heavier atoms. We have proposed a feasibility study for a Vibrational Spectroscopy Instrument (VSI) at the European Spallation Source ESS. Here, we will summarize the preliminary design calculations and the corresponding McStas simulation results for a possible ToF, Inverted Geometry, VSI beamline.

  3. VSI@ESS: Case study for a vibrational spectroscopy instrument at the european spallation source

    Directory of Open Access Journals (Sweden)

    Zoppi Marco

    2015-01-01

    Full Text Available Neutron Vibrational Spectroscopy is a well-established experimental technique where elementary excitations at relatively high frequency are detected via inelastic neutron scattering. This technique attracts a high interest in a large fraction of the scientific community in the fields of chemistry, materials science, physics, and biology, since one of its main applications exploits the large incoherent scattering cross section of the proton with respect to all the other elements, whose dynamics can be spectroscopically detected, even if dissolved in very low concentration in materials composed of much heavier atoms. We have proposed a feasibility study for a Vibrational Spectroscopy Instrument (VSI at the European Spallation Source ESS. Here, we will summarize the preliminary design calculations and the corresponding McStas simulation results for a possible ToF, Inverted Geometry, VSI beamline.

  4. Simulations towards optimization of a neutron/anti-neutron oscillation experiment at the European Spallation Source

    Science.gov (United States)

    Frost, Matthew; Kamyshkov, Yuri; Castellanos, Luis; Klinkby, Esben; US NNbar Collaboration

    2015-04-01

    The observation of Neutron/Anti-neutron oscillation would prove the existence of Baryon Number Violation (BNV), and thus an explanation for the dominance of matter over anti-matter in the universe. The latest experiments have shown the oscillation time to be greater than 8.6 x 107 seconds, whereas current theoretical predictions suggest times on the order of 108 to 109 seconds. A neutron oscillation experiment proposed at the European Spallation Source (ESS) would provide sensitivity of more than 1000 times previous experiments performed, thus providing a result well-suited to confirm or deny current theory. A conceptual design of the proposed experiment will be presented, as well as the optimization of key experiment components using Monte-Carlo simulation methods, including the McStas neutron ray-trace simulation package. This work is supported by the Organized Research Units Program funded by The University of Tennessee, Knoxville Office of Research and Engagement.

  5. Design of the low energy beam transport line for the China spallation neutron source

    Institute of Scientific and Technical Information of China (English)

    LI Jin-Hai; OUYANG Hua-Fu; FU Shi-Nian; ZHANG Sua-Shun; HE Wei

    2008-01-01

    The design of the China Spallation Neutron Source (CSNS) low-energy beam transport (LEBT) line, which locates between the ion source and the radio-frequency quadrupole (RFQ), has been completed with the TRACE3D code. The design aims at perfect matching, primary chopping, a small emittance growth and sufficient space for beam diagnostics. The line consists of three solenoids, three vacuum chambers, two steering magnets and a pre-chopper. The total length of LEBT is about 1.74 m. This LEBT is designed to transfer 20 mA of H-pulsed beam from the ion source to the RFQ. An induction cavity is adopted as the pre-chopper.The electrostatic octupole steerer is discussed as a candidate. A four-quadrant aperture for beam scraping and beam position monitoring is designed.

  6. Geant4 simulations of the neutron production and transport in the n_TOF spallation target

    Science.gov (United States)

    Lerendegui-Marco, J.; Cortés-Giraldo, M. A.; Guerrero, C.; Quesada, J. M.

    2016-11-01

    The neutron production and transport in the spallation target of the n_TOF facility at CERN has been simulated with Geant4. The results obtained with the different hadronic Physics Lists provided by Geant4 have been compared with the experimental neutron flux in n_TOF-EAR1. The best overall agreement in both the absolute value and the energy dependence of the flux from thermal to 1GeV, is obtained with the INCL++ model coupled with the Fritiof Model(FTFP). This Physics List has been thus used to simulate and study the main features of the new n_TOF-EAR2 beam line, currently in its commissioning phase.

  7. Comparisons of the simulation results using different codes for ADS spallation target

    CERN Document Server

    Yu Hong Wei; Shen Qing Biao; Wan Jun Sheng; Zhao Zhi Xiang

    2002-01-01

    The calculations to the standard thick target were made by using different codes. The simulation of the thick Pb target with length of 60 cm, diameter of 20 cm bombarded with 800, 1000, 1500 and 2000 MeV energetic proton beam was carried out. The yields and the spectra of emitted neutron were studied. The spallation target was simulated by SNSP, SHIELD, DCM/CEM (Dubna Cascade Model /Cascade Evaporation Mode) and LAHET codes. The Simulation Results were compared with experiments. The comparisons show good agreement between the experiments and the SNSP simulated leakage neutron yield. The SHIELD simulated leakage neutron spectra are in good agreement with the LAHET and the DCM/CEM simulated leakage neutron spectra

  8. Acceptance scan technique for the drift tube linac of the spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, D. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)]. E-mail: jeond@ornl.gov; Stovall, J. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Takeda, H. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Nath, S. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Billen, J. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Young, L. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Kisselev, I. [Institute for Nuclear Research of RAS, Troitsk, Russia (Russian Federation); Shishlo, A. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Aleksandrov, A. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Assadi, S. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Chu, C.M. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Cousineau, S. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Danilov, V. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Galambos, J. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Henderson, S. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Kim, S. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Kravchuk, L. [Institute for Nuclear Research of RAS, Troitsk, Russia (Russian Federation); Tanke, E. [SNS Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2007-01-01

    For high intensity proton accelerators, it is vital to reduce the machine activation by minimizing the beam loss from many sources. One of such sources is longitudinal mismatch. To minimize a potential mismatch, it is important to set accurately the rf set-point (rf field amplitude and phase) of a high-intensity linac such as the drift tube linac (DTL) of the spallation neutron source. A widely used technique called the acceptance scan was studied extensively and applied successfully to tune the DTL tanks since the initial commissioning. From the acceptance scan one can obtain the longitudinal beam profile at the entrance of each DTL tank. But except tank 1, acceptance scan alone cannot determine the incoming beam energy deviation, leading to small uncertainties in the rf set point.

  9. Experiment Automation with a Robot Arm using the Liquids Reflectometer Instrument at the Spallation Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Zolnierczuk, Piotr A [ORNL; Vacaliuc, Bogdan [ORNL; Sundaram, Madhan [ORNL; Parizzi, Andre A [ORNL; Halbert, Candice E [ORNL; Hoffmann, Michael C [ORNL; Greene, Gayle C [ORNL; Browning, Jim [ORNL; Ankner, John Francis [ORNL

    2013-01-01

    The Liquids Reflectometer instrument installed at the Spallation Neutron Source (SNS) enables observations of chemical kinetics, solid-state reactions and phase-transitions of thin film materials at both solid and liquid surfaces. Effective measurement of these behaviors requires each sample to be calibrated dynamically using the neutron beam and the data acquisition system in a feedback loop. Since the SNS is an intense neutron source, the time needed to perform the measurement can be the same as the alignment process, leading to a labor-intensive operation that is exhausting to users. An update to the instrument control system, completed in March 2013, implemented the key features of automated sample alignment and robot-driven sample management, allowing for unattended operation over extended periods, lasting as long as 20 hours. We present a case study of the effort, detailing the mechanical, electrical and software modifications that were made as well as the lessons learned during the integration, verification and testing process.

  10. Conceptual design of a cold methane moderator system for the European Spallation Source (ESS)

    CERN Document Server

    Barnert-Wiemer, H

    2002-01-01

    As part of the work for the target station of the planned European spallation source (ESS) the Central Department of Technology at the Forschungszentrum Juelich GmbH is also concerned with the moderators, particular attention being given to the development of cold methane moderators. This report discusses the technical feasibility of solid methane moderators. Methods to tailor the neutron output by adding absorption materials (decouplers or poisons) are not considered here, neither are composite moderators. Based on the given target-moderator-reflector assembly of the ESS project a concept for the ESS cold methane moderators has been developed and is being examined at the Forschungszentrum Juelich. According to this moderator concept the moderator is a fixed bed of small spheres, which makes moderator container filling homogeneous and reproducible. Since spheres form a defined packed bed, cooling of the moderator bed by H sub 2 is reliable. The process of filling the moderator container and of removing the pe...

  11. ACCELERATOR SYSTEMS MODIFICATIONS FOR A SECOND TARGET STATION AT THE OAK RIDGE SPALLATION NEUTRON SOURCE

    Energy Technology Data Exchange (ETDEWEB)

    Galambos, John D [ORNL; Kim, Sang-Ho [ORNL; Plum, Michael A [ORNL

    2014-01-01

    A second target station is planned for the Oak Ridge Spallation Neutron Source. The ion source will be upgraded to increase the peak current from 38 to 49 mA, additional superconducting RF cavities will be added to the linac to increase the H beam energy from 938 to 1300 MeV, and the accumulator ring will receive modifications to the injection and extraction systems to accommodate the higher beam energy. After pulse compression in the storage ring one sixth of the beam pulses (10 out of 60 Hz) will be diverted to the second target by kicker and septum magnets added to the existing Ring to Target Beam Transport (RTBT) line. No further modifications will be made to the RTBT so that when the kicker and septum magnets are turned off the original beam transport lattice will be unaffected. In this paper we will discuss these and other planned modifications and upgrades to the accelerator facility.

  12. Development of a fast traveling-wave beam chopper for the National Spallation Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Kurennoy, S.S.; Jason, A.J.; Krawczyk, F.L.; Power, J.

    1997-10-01

    High current and severe restrictions on beam losses, below 1 nA/m, in the designed linac for the National Spallation Neutron Source (NSNS) require clean and fast--with the rise time from 2% to 98% less than 2.5 ns to accommodate a 402.5-MHz beam structure--beam chopping in its front end, at the beam energy 2.5 MeV. The R and D program includes both modification of the existing LANSCE coax-plate chopper to reduce parasitic coupling between adjacent plates, and development of new traveling-wave deflecting structures, in particular, based on a meander line. Using analytical methods and three-dimensional time-domain computer simulations the authors study transient effects in such structures to choose an optimal chopper design.

  13. MEANDER-LINE CURRENT STRUCTURE DEVELOPMENT FOR SPALLATION NEUTRON SOURCE FAST CHOPPER

    Energy Technology Data Exchange (ETDEWEB)

    S. KURRENOY; J. POWER

    2000-10-01

    A new current structure for the fast traveling-wave 2.5-MeV beam chopper in the front end of the Spallation Neutron Source (SNS) has been suggested in [1]. The structure is based on the meander-folded notched stripline with dielectric supports and separators. Its design has been optimized using electromagnetic 3-D modeling with the MAFIA code package to provide rise and fall times in the range of 1 to 2 ns. A full-length (50 cm) prototype has been manufactured, and its preliminary measurements showed a good agreement with the calculations. Detailed measurements results and their comparison with simulations are presented. The latest front-end design requires a shorter, 35-cm chopper with a higher pulse voltage. Its meander-line current structure, based on the same principles, has also been optimized with MAFIA.

  14. Disentangling xenon components in Nakhla: martian atmosphere, spallation and martian interior^1

    Science.gov (United States)

    Gilmour, J. D.; Whitby, J. A.; Turner, G.

    2001-01-01

    A powdered sample of Nakhla was separated into 3 subsamples. One was left otherwise untreated, one was washed in water and one etched with HNO 3 removing 6% of the original mass. We report results of isotopic analysis of xenon released by laser step heating on aliquots of each of these subsamples; some aliquots were neutron irradiated before isotopic analysis (to allow determination of I, Ba and U as daughter xenon isotopes) and some were not. There is evidence that water soluble phases contain both martian atmospheric xenon and a component with low 129Xe/ 132Xe, either martian interior xenon or terrestrial atmosphere. Higher temperature data from unirradiated aliquots of the water and acid treated samples reveal two-component mixing. One is a trapped xenon component with 129Xe/ 132Xe = 2.350 ± 0.026, isotopically identical to the martian atmosphere as measured in shock glass from shergottites. It is associated with leachable iodine, suggesting it is trapped close to grain boundaries. It may be a result of shock incorporation of adsorbed atmospheric gas. The second component is best explained as an intimate mixture of martian interior xenon and spallation xenon. The martian interior component is present at a concentration of ˜10 -12 cm 3 STP g -1 132Xe, around 40 times lower than that observed in Chassigny. Its association with spallation xenon (produced from Ba and light rare earth elements) suggests it is in the feldspathic mesostasis. We propose that it was trapped during crystallisation and reflects the mantle source of the parental magma.

  15. Jet formation in spallation of metal film from substrate under action of femtosecond laser pulse

    Energy Technology Data Exchange (ETDEWEB)

    Inogamov, N. A., E-mail: nailinogamov@googlemail.com [Russian Academy of Sciences, Landau Institute for Theoretical Physics (Russian Federation); Zhakhovskii, V. V. [Dukhov All-Russia Research Institute of Automatics (Russian Federation); Khokhlov, V. A. [Russian Academy of Sciences, Landau Institute for Theoretical Physics (Russian Federation)

    2015-01-15

    It is well known that during ablation by an ultrashort laser pulse, the main contribution to ablation of the substance is determined not by evaporation, but by the thermomechanical spallation of the substance. For identical metals and pulse parameters, the type of spallation is determined by film thickness d{sub f}. An important gauge is metal heating depth d{sub T} at the two-temperature stage, at which electron temperature is higher than ion temperature. We compare cases with d{sub f} < d{sub T} (thin film) and d{sub f} ≫ d{sub T} (bulk target). Radius R{sub L} of the spot of heating by an optical laser is the next (after d{sub f}) important geometrical parameter. The morphology of film bulging in cases where d{sub f} < d{sub T} on the substrate (blistering) changes upon a change in radius R{sub L} in the range from diffraction limit R{sub L} ∼ λ to high values of R{sub L} ≫ λ, where λ ∼ 1 μm is the wavelength of optical laser radiation. When d{sub f} < d{sub T}, R{sub L} ∼ λ, and F{sub abs} > F{sub m}, gold film deposited on the glass target acquires a cupola-shaped blister with a miniature frozen nanojet in the form of a tip on the circular top of the cupola (F{sub abs} and F{sub m} are the absorbed energy and the melting threshold of the film per unit surface area of the film). A new physical mechanism leading to the formation of the nanojet is proposed.

  16. Thermal-hydraulic simulation of mercury target concepts for a pulsed spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Siman-Tov, M.; Wendel, M.; Haines, J. [Oak Ridge National Lab., TN (United States)

    1996-06-01

    The Oak Ridge Spallation Neutron Source (ORSNS) is a high-power, accelerator-based pulsed spallation neutron source being designed by a multi-laboratory team led by Oak Ridge National Laboratory to achieve very high fluxes of neutrons for scientific experiments. The ORSNS is projected to have a 1 MW proton beam upgradable to 5 MW. About 60% of the beam power (1-5 MW, 17-83 kJ/pulse in 0.5 microsec at 60 cps) is deposited in the liquid metal (mercury) target having the dimensions of 65x30x10 cm (about 19.5 liter). Peak steady state power density is about 150 and 785 MW/m{sup 3} for 1 MW and 5 MW beam respectively, whereas peak pulsed power density is as high as 5.2 and 26.1 GW/m{sup 3}, respectively. The peak pulse temperature rise rate is 14 million C/s (for 5 MW beam) whereas the total pulse temperature rise is only 7 C. In addition to thermal shock and materials compatibility, key feasibility issues for the target are related to its thermal-hydraulic performance. This includes proper flow distribution, flow reversals, possible {open_quotes}hot spots{close_quotes} and the challenge of mitigating the effects of thermal shock through possible injection of helium bubbles throughout the mercury volume or other concepts. The general computational fluid dynamics (CFD) code CFDS-FLOW3D was used to simulate the thermal and flow distribution in three preliminary concepts of the mercury target. Very initial CFD simulation of He bubbles injection demonstrates some potential for simulating behavior of He bubbles in flowing mercury. Much study and development will be required to be able to `predict`, even in a crude way, such a complex phenomena. Future direction in both design and R&D is outlined.

  17. Substrate-induced coagulation (SIC) of nano-disperse alumina in non-aqueous media: The dispersibility and stability of alumina in N-methyl-2-pyrrolidinone

    OpenAIRE

    Basch, Angelika; Strnad, Simona

    2011-01-01

    This work investigated colloidal properties such as the zeta-potential, the electrophoretic mobilities and the wetting behaviour of alumina dispersed in non-aqueous media. Non-aqueous dispersions of alumina were prepared in the solvent N-methyl-2-pyrrolidinone (NMP). The wetting behaviour of alumina in NMP was characterized by the powder contact angle method and the Wilhemy plate method. The behaviour of the dispersion should provide information for the development of a substrate-induced coag...

  18. A General Procedure for Surface Modification of Nano-alumina and Its Application to Dendrimers

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A general procedure for surface modification of nano-alumina using N, N'-dicyclohexyl-carbodiimide (DCC) mediated amidation is reported. Aliphatic and aromatic carboxylic acids reacted smoothly with nano-alumina pretreated with 3-aminopropyltriethoxysilane in the presence of DCC, giving modified aluminas having organic surfaces. The grafted aluminas have been characterized qualitatively by FT-IR or 13C CPMAS NMR spectroscopy, and quantitatively by thermogravimetric analysis and elemental analysis. The procedure was applied to polyether dendrons bearing carboxyl groups at the focal points, giving successful grafting of dendrimers onto nano-alumina.

  19. Effect of La2O3 on Microstructure and Transmittance of Transparent Alumina Ceramics

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Optically transparent alumina ceramics were fabricated by conventional process and sintered without pressure in H2 atmosphere. The results indicate that relative densities of alumina specimens increase to theoretical densities (T.D.) with increasing content of La2O3. With increasing holding time during sintering, much less pores and larger grains were found in the sintered alumina samples. Higher transmittance was achieved in alumina codoped with MgO and La2O3 as compared with that doped with MgO only. The total-transmittance of alumina sample is up to 86% at a wavelength range of 300~800 nm.

  20. Gas and surface diffusion in modified γ-alumina systems

    NARCIS (Netherlands)

    Uhlhorn, R.J.R.; Keizer, K.; Burggraaf, A.J.

    1989-01-01

    The transport of pure gases through a microporous membrane is described. The alumina-based membrane (pores 2.5-4 nm) is suitable for Knudsen diffusion separation. To improve the separation factor, interaction with and mobility on the pore wall of one of the gases of a mixture is necessary. To introd

  1. Experiments on individual alumina-supported adatoms and clusters

    Science.gov (United States)

    Nilius, N.; Cörper, A.; Bozdech, G.; Ernst, N.; Freund, H.-J.

    2001-08-01

    To contribute to an understanding of growth conditions and electronic properties of metal clusters on technologically relevant oxides we have examined the mobility of individual, alumina-supported Pt-adatoms and the optical properties of single supported Ag-clusters. Using field-ion microscopy (FIM) we have prepared and imaged an individual Pt-adatom at approximately 40 K, both on the apex plane of a [1 1 0]-oriented NiAl tip and on a thin alumina film, grown on the same NiAl specimen by oxidation. On the alumina film, the onset temperature for Pt surface diffusion approaches 100 K being distinctively lower than the value 165 K measured on NiAl(1 1 0). Employing the tip of a scanning tunneling microscope (STM) as a local electron source, photon emission from individual, alumina-supported Ag-clusters was spectroscopically analyzed. The occurrence of a distinct emission line is explained by the decay of a collective electron oscillation (Mie-plasmon resonance). For decreasing Ag-cluster diameter, the emission lines (i) shift to higher energies and (ii) their widths increase. To explain these observations, we discuss (i) the reduced screening of the plasmon oscillation due to the Ag 4d electrons and (ii) an enhanced electron surface scattering rate in small clusters.

  2. Osseointegration of alumina bioceramic granules: A comparative experimental study

    Science.gov (United States)

    Rerikh, V. V.; Avetisyan, A. R.; Zaydman, A. M.; Anikin, K. A.; Bataev, V. A.; Nikulina, A. A.; Sadovoy, M. A.; Aronov, A. M.; Semantsova, E. S.

    2016-08-01

    To perform a comparative analysis of osseointegration of bioceramic alumina-based granules, hydroxyapatite-based granules, and deproteinized bone granules. The experiment was conducted on 52 adult male Kyoto-Wistar rats weighing 350 to 520 g. The animals were divided into five matched groups that differed only in the type of an implanted material. The granules were implanted in the lumbar vertebral bodies and in the distal right femur of each laboratory animal. Two months after surgery, the animals were euthanized, followed by tissue sampling for morphological studies. An examination of specimens from the groups with implanted alumina granules revealed the newly formed trabecular bone with remodeling signs. The bone tissue filled the intragranular space, tightly adhering to the granule surface. There was no connective tissue capsule on the border between bone tissue and alumina granules. Cylindrical bioceramic alumina-based granules with an open internal channel have a higher strength surpassing than that of analogs and the osseointegration ability close to that of hydroxyapatite and deproteinized bone granules.

  3. Capillary condensation in porous alumina observed by positronium lifetime spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Eugeniu [National Institute for Nuclear Physics and Engineering-Horia Hulubei, Atomistilor Street 407, CP MG 06, Magurele, Bucharest (Romania); Center for Advanced Studies in Physics of the Roumanian Academy, Casa Academiei Romane, Calea 13 Septembrie No. 13, Bucharest (Romania); Vata, Ion [National Institute for Nuclear Physics and Engineering-Horia Hulubei, Atomistilor Street 407, CP MG 06, Magurele, Bucharest (Romania)], E-mail: vata@ifin.nipne.ro; Toderian, Stefan; Dudu, Dorin; Rusen, Ion; Stefan, Nitisor [National Institute for Nuclear Physics and Engineering-Horia Hulubei, Atomistilor Street 407, CP MG 06, Magurele, Bucharest (Romania)

    2008-10-31

    The PALS method based on time distribution measurements has been used to study capillary condensation of different gases adsorbed in microporous alumina powder. The isotherms exhibit features which are associated with a shifted gas-liquid transition. The sorption and desorption processes are irreversible presenting a hysteresis effect. Suggestions on some new aspects of the capillary condensation dynamics are made.

  4. Laser-induced prenucleation of alumina for electroless plating

    NARCIS (Netherlands)

    Shrivastva, P.B.; Harteveld, C.; Boose, C.A.; Kolster, B.H.

    1991-01-01

    This paper deals with the deposition of palladium from decomposition of a thin palladium acetate layer on rough and porous alumina ceramic surfaces by irradiating it with a UV excimer laser. The palladium acetate layer was formed from a combination of propyl glycol methyl ether acetate solvent and p

  5. Structure and surface properties of praseodymium modified alumina

    Energy Technology Data Exchange (ETDEWEB)

    Tankov, I. [Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Pawelec, B. [Instituto de Catalisis y Petroleoquimica, CSIC, Cantoblanco, 28049 Madrid (Spain); Arishtirova, K. [Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Damyanova, S., E-mail: soniad@ic.bas.bg [Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)

    2011-10-15

    Mixed PrO{sub 2}-Al{sub 2}O{sub 3} oxides with different PrO{sub 2} content (1-20 wt.%) were prepared by wetness impregnation of {gamma}-alumina with aqueous solution of praseodymium nitrate. The samples were characterized by different techniques, using surface adsorption-desorption of N{sub 2} (S{sub BET}), thermogravimetric analysis (TGA), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (DRS), temperature-programmed reduction (TPR) and temperature-programmed desorption of CO{sub 2} (TPD-CO{sub 2}). TGA and XRD showed the presence of small praseodymium oxide species on the alumina surface. XPS and DRS detected electron deficient interaction between deposited praseodymium oxide and alumina. It was observed a lower reduction temperature for supported Pr oxide species compared to that of the bulk Pr{sub 6}O{sub 11}. TPD-CO{sub 2} studies suggested that the deposition of Pr oxide on alumina leaded to increase of the basicity of mixed oxides.

  6. Multifunctional substrates of thin porous alumina for cell biosensors

    KAUST Repository

    Toccafondi, Chiara

    2014-02-27

    We have fabricated anodic porous alumina from thin films (100/500 nm) of aluminium deposited on technological substrates of silicon/glass, and investigated the feasibility of this material as a surface for the development of analytical biosensors aiming to assess the status of living cells. To this goal, porous alumina surfaces with fixed pitch and variable pore size were analyzed for various functionalities. Gold coated (about 25 nm) alumina revealed surface enhanced Raman scattering increasing with the decrease in wall thickness, with factor up to values of approximately 104 with respect to the flat gold surface. Bare porous alumina was employed for micro-patterning and observation via fluorescence images of dye molecules, which demonstrated the surface capability for a drug-loading device. NIH-3T3 fibroblast cells were cultured in vitro and examined after 2 days since seeding, and no significant (P > 0.05) differences in their proliferation were observed on porous and non-porous materials. The effect on cell cultures of pore size in the range of 50–130 nm—with pore pitch of about 250 nm—showed no significant differences in cell viability and similar levels in all cases as on a control substrate. Future work will address combination of all above capabilities into a single device.

  7. Dynamical stability of the alpha and theta phases of alumina

    DEFF Research Database (Denmark)

    Lodziana, Zbigniew; Parlinski, K.

    2003-01-01

    Using density functional calculations the phonon dispersion relations, phonon density of states, and free energy of theta and alpha phases of alumina are investigated. The temperature dependence of the free energy indicates that entropy contributes to the destabilization of the alpha phase at the...

  8. Joining between alumina and metal by use of plasma sprayed Ni-Al coating on alumina. Alumina ni plasma yoshashita Ni-Al kinzoku himaku wo kaishite no alumina kinzoku tono setsugo

    Energy Technology Data Exchange (ETDEWEB)

    Murakami, N.; Kishitake, K.; Hasebe, M.; Kobayashi, T.; Murashige, K. (Kyushu Institute of Technology, Kitakyushu (Japan). Faculty of Engineering)

    1993-06-30

    A ceramic material is joined and compounded with a metal by spraying another metal on the ceramic material, and then joined with the intended metal because of small adhesion strength in both materials. Adhesion strength of the spraying metal is important even in this case. The present experiment performed plasma spraying of Ni-Al mixed powder on alumina to investigate effects of the heating on the adhesion strength. Solder joining of Ni-Al sprayed alumina with soft steel rod and copper rod was also tested. As a result, the adhesion strength of as-sprayed Ni-Al film on the alumina was about 5 MPa and maximum of 10 MPa. Heating the materials to 1173 K for 10 hours or longer provided an average strength of 20 MPa and a maximum strength of 35 MPa. Improving the adhesion strength requires spinel to be produced through reactions on the interface. It was found that alumina can be joined with metal easily by going through this film. 12 refs., 6 figs.

  9. Thin alumina and silica films by chemical vapor deposition (CVD)

    NARCIS (Netherlands)

    Hofman, R.; Morssinkhof, R.W.J.; Fransen, T.; Westheim, J.G.F.; Gellings, P.J.

    1993-01-01

    Alumina and silica coatings have been deposited by MOCVD (Metal Organic Chemical Vapor Deposition) on alloys to protect them against high temperature corrosion. Aluminium Tri-lsopropoxide (ATI) and DiAcetoxyDitertiaryButoxySilane (DAOBS) have been used as metal organic precursors to prepare these ce

  10. N-doped mesoporous alumina for adsorption of carbon dioxide

    Institute of Scientific and Technical Information of China (English)

    Jayshri A.Thote; Ravikrishna V.Chatti; Kartik S.Iyer; Vivek Kumar; Arti N.Valechha; Nitin K.Labhsetwar; Rajesh B.Biniwale; M.K.N.Yenkie; Sadhana S.Rayalu

    2012-01-01

    N-doped mesoporous alumina has been synthesized using chitosan as the biopolymer template.The adsorbent has been thoroughly investigated for the adsorption of CO2 from a simulated flue gas stream (15% CO2 balanced with N2) and compared with commercially available mesoporous alumina procured from SASOL,Germany.CO2 adsorption was studied under different conditions of pretreatment and adsorption temperature,inlet CO2 concentration and in the presence of oxygen and moisture.The adsorption capacity was determined to be 29.4 mg CO2/g of adsorbent at 55℃.This value was observed to be 4 times higher in comparison to that of commercial mesoporous alumina at a temperature of 55℃.Basicity of alumina surface coupled with the presence of nitrogen in template in synthesized sample is responsible for this enhanced CO2 adsorption.Adsorption capacity for CO2 was retained in the presence of oxygen; however moisture had a deteriorating effect on the adsorption capacity reducing it to nearly half the value.

  11. The Adsorption of Cr(VI Using Chitosan-Alumina Adsorbent

    Directory of Open Access Journals (Sweden)

    Darjito Darjito

    2013-12-01

    Full Text Available Chitosan as adsorbent has been used widely, however it was not effective yet for metal ions adsorption in industrial scale. In acidic condition, chitosan’s active site tends to decrease. This drawback can was solved by coating of chitosan active site on alumina. This paper discloses to overcome that limitation. The charateristic of the active side was analysed by FTIR spectrometry toward vibration N-H group at 1679.15 cm-1, C=O group of oxalate at 1703.30 cm-1, and Al-O group of alumina at 924.07 cm-1. The adsorption capacity of the developed adsorbent was tester to adsorb Cr(VI ions under various of pH value such as 1, 2, 3, 4, 5, 6, and 7. The contact time affect toward the adsorption was also reported in 20, 30, 40 50, 60, 70, and 80 minute. In addition, the concentration effects (100, 200, 300, 400, 500, and 600 ppm was also studied. Chromium (VI was measured using spectronic-20. Adsorption capacity was obtained at 66.90 mg/g under optimum conditions pH 2, and contact time 60 minute, respectively.

  12. Advanced morphological analysis of patterns of thin anodic porous alumina

    Energy Technology Data Exchange (ETDEWEB)

    Toccafondi, C. [Istituto Italiano di Tecnologia, Department of Nanophysics, Via Morego 30, Genova I 16163 (Italy); Istituto Italiano di Tecnologia, Department of Nanostructures, Via Morego 30, Genova I 16163 (Italy); Stępniowski, W.J. [Department of Advanced Materials and Technologies, Faculty of Advanced Technologies and Chemistry, Military University of Technology, 2 Kaliskiego Str., 00-908 Warszawa (Poland); Leoncini, M. [Istituto Italiano di Tecnologia, Department of Nanostructures, Via Morego 30, Genova I 16163 (Italy); Salerno, M., E-mail: marco.salerno@iit.it [Istituto Italiano di Tecnologia, Department of Nanophysics, Via Morego 30, Genova I 16163 (Italy)

    2014-08-15

    Different conditions of fabrication of thin anodic porous alumina on glass substrates have been explored, obtaining two sets of samples with varying pore density and porosity, respectively. The patterns of pores have been imaged by high resolution scanning electron microscopy and analyzed by innovative methods. The regularity ratio has been extracted from radial profiles of the fast Fourier transforms of the images. Additionally, the Minkowski measures have been calculated. It was first observed that the regularity ratio averaged across all directions is properly corrected by the coefficient previously determined in the literature. Furthermore, the angularly averaged regularity ratio for the thin porous alumina made during short single-step anodizations is lower than that of hexagonal patterns of pores as for thick porous alumina from aluminum electropolishing and two-step anodization. Therefore, the regularity ratio represents a reliable measure of pattern order. At the same time, the lower angular spread of the regularity ratio shows that disordered porous alumina is more isotropic. Within each set, when changing either pore density or porosity, both regularity and isotropy remain rather constant, showing consistent fabrication quality of the experimental patterns. Minor deviations are tentatively discussed with the aid of the Minkowski measures, and the slight decrease in both regularity and isotropy for the final data-points of the porosity set is ascribed to excess pore opening and consequent pore merging. - Highlights: • Thin porous alumina is partly self-ordered and pattern analysis is required. • Regularity ratio is often misused: we fix the averaging and consider its spread. • We also apply the mathematical tool of Minkowski measures, new in this field. • Regularity ratio shows pattern isotropy and Minkowski helps in assessment. • General agreement with perfect artificial patterns confirms the good manufacturing.

  13. Synthesis and structural evaluation of freeze-cast porous alumina

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Douglas F., E-mail: souzadf@outlook.com [Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais — UFMG, Avenida Presidente Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, MG CEP: 31270-901, Escola de Engenharia, bloco 2, sala 2230 (Brazil); Nunes, Eduardo H.M., E-mail: eduardohmn@gmail.com [Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais — UFMG, Avenida Presidente Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, MG CEP: 31270-901, Escola de Engenharia, bloco 2, sala 2230 (Brazil); Pimenta, Daiana S.; Vasconcelos, Daniela C.L. [Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais — UFMG, Avenida Presidente Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, MG CEP: 31270-901, Escola de Engenharia, bloco 2, sala 2230 (Brazil); Nascimento, Jailton F.; Grava, Wilson [Petrobras/CENPES, Avenida Horácio Macedo 950, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, RJ CEP:21941-915 (Brazil); Houmard, Manuel [Department of Materials Engineering and Civil Construction, Federal University of Minas Gerais — UFMG, Avenida Presidente Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, MG CEP: 31270-901, Escola de Engenharia, bloco 1, sala 3304 (Brazil); Vasconcelos, Wander L., E-mail: wlv@demet.ufmg.br [Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais — UFMG, Avenida Presidente Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, MG CEP: 31270-901, Escola de Engenharia, bloco 2, sala 2230 (Brazil)

    2014-10-15

    In this work we fabricated alumina samples by the freeze-casting technique using tert-butanol as the solvent. The prepared materials were examined by scanning electron microscopy and X-ray microtomography. Next, they were coated with sol–gel silica films by dip-coating. Permeability tests were carried out in order to assess the permeation behavior of the materials processed in this study. We observed that the sintering time and alumina loading showed a remarkable effect on both the structural properties and flexural strength of the freeze-cast samples. Nitrogen adsorption tests revealed that the silica prepared in this study exhibited a microporous structure. It was observed that the presence of silica coatings on the alumina surface decreased the CO{sub 2} permeance by about one order of magnitude. Because of the similar kinetic diameters of nitrogen and carbon dioxide, the CO{sub 2}/N{sub 2} system showed a separation efficiency that was lower than that observed for the He/CO{sub 2} and He/N{sub 2} systems. We noticed that increasing the feed pressure improved the separation capacity of the obtained materials. - Highlights: • Porous alumina samples obtained by the freeze-casting technique • Microporous silica coating prepared by a simple sol–gel dip-coating methodology • Samples examined by SEM, μ-CT, and nitrogen sorption tests • Mechanical tests were carried out in the freeze-cast samples. • The presence of silica coatings on the alumina surface decreased the CO{sub 2} permeance.

  14. The reactive element effect of ceria particle dispersion on alumina growth: A model based on microstructural observations

    Science.gov (United States)

    Wang, X.; Peng, X.; Tan, X.; Wang, F.

    2016-07-01

    The oxidation kinetics of alumina-forming metals can be affected by adding a small amount of a reactive (normally rare earth) element oxide (RExOy) and the segregation of the reactive element (RE) ions to the growing alumina grain boundaries (GBs) has been considered as a responsible reason. However, this interpretation remains a controversial issue as to how RE ions are produced by RExOy which is thermodynamically and chemically stable in metals. The question is answered by a model that is based on transmission electron microscopy (TEM) investigation of a CeO2-dispersed nickel aluminide oxidized in air at 1100 °C. The CeO2 dispersion is incorporated into the alumina scale by the inward growth of inner α-Al2O3, where it partially dissolves producing tetravalent Ce cations which then transform to trivalent cations by trapping electrons. The trivalent cations segregate to the α-Al2O3 GBs and diffuse outward along first the GBs and later the twin boundaries (TBs) in the outer γ-Al2O3 layer, being precipitated as Ce2O3 particles near surface.

  15. Spallation reaction study for fission products in nuclear waste: Cross section measurements for 137Cs and 90Sr on proton and deuteron

    Science.gov (United States)

    Wang, H.; Otsu, H.; Sakurai, H.; Ahn, D. S.; Aikawa, M.; Doornenbal, P.; Fukuda, N.; Isobe, T.; Kawakami, S.; Koyama, S.; Kubo, T.; Kubono, S.; Lorusso, G.; Maeda, Y.; Makinaga, A.; Momiyama, S.; Nakano, K.; Niikura, M.; Shiga, Y.; Söderström, P.-A.; Suzuki, H.; Takeda, H.; Takeuchi, S.; Taniuchi, R.; Watanabe, Ya.; Watanabe, Yu.; Yamasaki, H.; Yoshida, K.

    2016-03-01

    We have studied spallation reactions for the fission products 137Cs and 90Sr for the purpose of nuclear waste transmutation. The spallation cross sections on the proton and deuteron were obtained in inverse kinematics for the first time using secondary beams of 137Cs and 90Sr at 185 MeV/nucleon at the RIKEN Radioactive Isotope Beam Factory. The target dependence has been investigated systematically, and the cross-section differences between the proton and deuteron are found to be larger for lighter spallation products. The experimental data are compared with the PHITS calculation, which includes cascade and evaporation processes. Our results suggest that both proton- and deuteron-induced spallation reactions are promising mechanisms for the transmutation of radioactive fission products.

  16. Spallation reaction study for fission products in nuclear waste: Cross section measurements for 137Cs and 90Sr on proton and deuteron

    Directory of Open Access Journals (Sweden)

    H. Wang

    2016-03-01

    Full Text Available We have studied spallation reactions for the fission products 137Cs and 90Sr for the purpose of nuclear waste transmutation. The spallation cross sections on the proton and deuteron were obtained in inverse kinematics for the first time using secondary beams of 137Cs and 90Sr at 185 MeV/nucleon at the RIKEN Radioactive Isotope Beam Factory. The target dependence has been investigated systematically, and the cross-section differences between the proton and deuteron are found to be larger for lighter spallation products. The experimental data are compared with the PHITS calculation, which includes cascade and evaporation processes. Our results suggest that both proton- and deuteron-induced spallation reactions are promising mechanisms for the transmutation of radioactive fission products.

  17. Spallation reaction study for fission products in nuclear waste: Cross section measurements for {sup 137}Cs and {sup 90}Sr on proton and deuteron

    Energy Technology Data Exchange (ETDEWEB)

    Wang, H., E-mail: wanghe@ribf.riken.jp [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Otsu, H.; Sakurai, H.; Ahn, D.S. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Aikawa, M. [Faculty of Science, Hokkaido University, Sapporo 060-0810 (Japan); Doornenbal, P.; Fukuda, N.; Isobe, T. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Kawakami, S. [Department of Applied Physics, University of Miyazaki, Miyazaki 889-2192 (Japan); Koyama, S. [Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033 (Japan); Kubo, T.; Kubono, S.; Lorusso, G. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Maeda, Y. [Department of Applied Physics, University of Miyazaki, Miyazaki 889-2192 (Japan); Makinaga, A. [Graduate School of Medicine, Hokkaido University, North-14, West-5, Kita-ku, Sapporo 060-8648 (Japan); Momiyama, S. [Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033 (Japan); Nakano, K. [Department of Advanced Energy Engineering Science, Kyushu University, Kasuga, Fukuoka 816-8580 (Japan); Niikura, M. [Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033 (Japan); Shiga, Y. [Department of Physics, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo 171-8501 (Japan); RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Söderström, P.-A. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); and others

    2016-03-10

    We have studied spallation reactions for the fission products {sup 137}Cs and {sup 90}Sr for the purpose of nuclear waste transmutation. The spallation cross sections on the proton and deuteron were obtained in inverse kinematics for the first time using secondary beams of {sup 137}Cs and {sup 90}Sr at 185 MeV/nucleon at the RIKEN Radioactive Isotope Beam Factory. The target dependence has been investigated systematically, and the cross-section differences between the proton and deuteron are found to be larger for lighter spallation products. The experimental data are compared with the PHITS calculation, which includes cascade and evaporation processes. Our results suggest that both proton- and deuteron-induced spallation reactions are promising mechanisms for the transmutation of radioactive fission products.

  18. EFFECTIVE ELASTIC PROPERTIES OF ALUMINA-ZIRCONIA COMPOSITE CERAMICS - PART 4. TENSILE MODULUS OF POROUS ALUMINA AND ZIRCONIA

    Directory of Open Access Journals (Sweden)

    W. Pabst

    2004-12-01

    Full Text Available In this fourth paper of a series on the effective elastic properties of alumina-zirconia composite ceramics the influence of porosity on the effective tensile modulus of alumina and zirconia ceramics is discussed. The examples investigated are alumina and zirconia ceramics prepared from submicron powders by starch consolidation casting using two different types of starch, potato starch (median size D50 =47.2 µm and corn starch (median size D50 =13.7 µm. The dependence of effective tensile moduli E, on the porosity f, measured for porosities in the ranges of approx. 19-55 vol.% and 10-42 vol.% for alumina and zirconia, respectively, using a resonant frequency technique, was evaluated by fitting with various model relations, including newly developed ones. A detailed comparison of the fitting results suggests the superiority of the new relation E/E0 = (1 - f·(1 - f/fC, developed by the authors (with the tensile modulus of the dense ceramic material E0 and the critical porosity fC, over most other existing fit models. Only for special purposes and well-behaved data sets the recently proposed exponential relation E/E0 = exp [-Bf/(1 - f] and the well-known Phani-Niyogi relation E/E0 = (1 - f/fCN might be preferable.

  19. Porous alumina, zirconia and alumina/zirconia for bone repair: fabrication, mechanical and in vitro biological response.

    Science.gov (United States)

    Hadjicharalambous, Chrystalleni; Buyakov, Ales; Buyakova, Svetlana; Kulkov, Sergey; Chatzinikolaidou, Maria

    2015-04-23

    Zirconia (ZrO2) and alumina (Al2O3) based ceramics are widely used for load-bearing applications in bone repair due to their excellent mechanical properties and biocompatibility. They are often regarded as bioinert since no direct bone-material interface is created unless a porous structure intercedes, leading to better bone bonding. In this regard, investigating interactions between cells and porous ceramics is of great interest. In the present study, we report on the successful fabrication of sintered alumina A-61, zirconia Z-50 and zirconia/alumina composite ZA-60 ceramics with medium porosities of 61, 50 and 60%, respectively, indicating a bimodal pore size distribution and good interconnectivity. They exhibit elastic moduli of 3-10 GPa and compressive strength values of 60-240 MPa, similar to those of human cortical bone.We performed in vitro cell-material investigations comparing the adhesion, proliferation and differentiation of mouse pre-osteoblasts MC3T3-E1 on the three porous materials. While all three ceramics demonstrate a strong cell attachment, better cell spreading is observed on zirconia-containing substrates. Significantly higher cell growth was quantified on the latter ceramics, revealing an increased alkaline phosphatase activity, higher collagen production and increased calcium biomineralization compared to A-61. Hence, these porous zirconia-containing ceramics elicit superior biological responses over porous alumina of similar porosity, promoting enhanced biological interaction, with potential use as non-degradable bone grafts or as implant coatings.

  20. Aqueous-Phase Preparation of Model HDS Catalysts on Planar Alumina Substrates: Support Effect on Mo Adsorption and Sulfidation.

    Science.gov (United States)

    Bara, Cédric; Plais, Lucie; Larmier, Kim; Devers, Elodie; Digne, Mathieu; Lamic-Humblot, Anne-Félicie; Pirngruber, Gerhard D; Carrier, Xavier

    2015-12-23

    The role of the oxide support on the structure of the MoS2 active phase (size, morphology, orientation, sulfidation ratio, etc.) remains an open question in hydrotreating catalysis and biomass processing with important industrial implications for the design of improved catalytic formulations. The present work builds on an aqueous-phase surface-science approach using four well-defined α-alumina single crystal surfaces (C (0001), A (112̅0), M (101̅0), and R (11̅02) planes) as surrogates for γ-alumina (the industrial support) in order to discriminate the specific role of individual support facets. The reactivity of the various surface orientations toward molybdenum adsorption is controlled by the speciation of surface hydroxyls that determines the surface charge at the oxide/water interface. The C (0001) plane is inert, and the R (11̅02) plane has a limited Mo adsorption capacity while the A (112̅0) and M (101̅0) surfaces are highly reactive. Sulfidation of model catalysts reveals the highest sulfidation degree for the A (112̅0) and M (101̅0) planes suggesting weak metal/support interactions. Conversely, a low sulfidation rate and shorter MoS2 slabs are found for the R (11̅02) plane implying stronger Mo-O-Al bonds. These limiting cases are reminiscent of type I/type II MoS2 nanostructures. Structural analogies between α- and γ- alumina surfaces allow us to bridge the material gap with real Al2O3-supported catalysts. Hence, it can be proposed that Mo distribution and sulfidation rate are heterogeneous and surface-dependent on industrial γ-Al2O3-supported high-surface-area catalysts. These results demonstrate that a proper control of the γ-alumina morphology is a strategic lever for a molecular-scale design of hydrotreating catalysts.

  1. Effect of Impurities on O and Al Boundary Diffusion in Alumina: Application Alumina Scale Growth in Alloys

    Science.gov (United States)

    2012-01-24

    Martin P Harmer - PI Helen M Chan - CoPI Jeffrey M Rickman - CoPI 5d. PROJECT NUMBER 11PR03456-01 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7...PERSON Martin P. Harmer 19b. TELEPHONE NUMBER (Include area code) 610-758^227 Standard Form 298 (Rev. 8/98) Prescribed by ANSI Std Z39.18 ONR Final...the trajectories of the diffusion ions. 35 References 1. H. Cheng, S. Dillon, H. Caram, J.M, Rickman, H.M. Chan and M.P. Harmer , " The Effect of

  2. A 4p BaF2 detector for (n,g) cross section measurements at a spallation neutron source

    CERN Document Server

    Heil, M; Fowler, M M; Haight, R C; Käppeler, F; Rundberg, R S; Seabury, E H; Ullmann, J L; Wilhelmy, J B; Wisshak, K

    2013-01-01

    The quest for improved neutron capture cross sections for advanced reactor concepts, transmutation of radioactive wastes as well as for astrophysical scenarios of neutron capture nucleosynthesis has motivated new experimental efforts based on modern techniques. Recent measurements in the keV region have shown that a 4p BaF2 detector represents an accurate and versatile instrument for such studies. The present work deals with the potential of such a 4p BaF2 detector in combination with spallation neutron sources, which offer large neutron fluxes over a wide energy range. Detailed Monte Carlo simulations with the GEANT package have been performed to investigate the critical backgrounds at a spallation facility, to optimize the detector design, and to discuss alternative solutions.

  3. "Innovation and Intellectual Property Policies in European Research Infrastructure Consortia - PART I: The Case of the European Spallation Source ERIC"

    DEFF Research Database (Denmark)

    Yu, Helen; Wested, Jakob; Minssen, Timo

    2017-01-01

    of the problems society is facing today. To facilitate the creation and operation of such RIs, the EU adopted legal frameworks for European Research Infrastructure Consortia (ERIC). On August 31, 2015, the European Spallation Source (ESS) was established as an ERIC. Under the ERIC Regulations and ESS Statutes......Research and innovation are key pillars of the EU’s strategy to create sustainable growth and prosperity in Europe. Research infrastructures (RIs) are central instruments to implement this strategy. They bring together a wide diversity of expertise and interests to look for solutions to many......, the European Spallation Source ERIC is required to adopt various policy documents relating to the operation and management of the facility. These cover a wide variety of issues such as user access, public procurement, intellectual property rights (IPR), data management, and dissemination. One of the main goals...

  4. Decommissioning and safety issues of liquid-mercury waste generated from high power spallation sources with particle accelerators

    CERN Document Server

    Chiriki, S; Odoj, R; Moormann, R; Hinssen, H. K; Bukaemskiy, A

    2009-01-01

    Large spallation sources are intended to be constructed in Europe (EURISOL nuclear physics facility and ESS-European Spallation Source). These facilities accumulate more than 20 metric tons of irradiated mercury in the target, which has to be treated as highly radioactive and chemo-toxic waste. Because solids are the only appropriate (immobile) form for this radiotoxic and toxic type of waste solidification is required for irradiated mercury. Our irradiation experimental studies on mercury waste revealed that mercury sulfide is a reasonable solid for disposal and shows larger stability in assumed accidents with water ingress in a repository compared to amalgams. For preparation of mercury sulfide a wet process is more suitable than a dry one. It is easier to perform under hot cell conditions and allows complete Hg-conversion. Embedding HgS in a cementitious matrix increases its stability.

  5. Physical Design of Critical Experiment Facility for Verifying Characteristics and Effects of Coupling Between Reactor and Spallation Target of ADS

    Institute of Scientific and Technical Information of China (English)

    YIN; Sheng-gui; ZHOU; Qi; LI; Yan

    2013-01-01

    For the purpose of studying and verifying characteristics and effects of coupling between reactor and spallation target of ADS,based on the critical experimental facility design criteria and the availableexperiment condition,physical design of a critical experiment facility with lead coolant is completed,using critical calculation code MONK-9A.The contents of physical designs mainly include nuclear fuel,array of fuel rods,neutron source

  6. Measurement of isotopic cross sections of spallation residues in 800 A MeV {sup 197}Au + p collisions

    Energy Technology Data Exchange (ETDEWEB)

    Rejmund, F.; Mustapha, B.; Bernas, M.; Stephan, C.; Taieb, J.; Tassan-Got, L. [Institut de Physique Nucleaire, (IN2P3/CNRS) 91 - Orsay (France); Armbruster, P.; Benlliure, J.; Enqvist, T.; Schmidt, K.H.; Taieb, J. [GSI, Planckstrasse, Darmstadt (Germany); Benlliure, J. [Universidad de Santiago de Compostela (Spain); Boudard, A.; Legrain, R.; Leray, S.; Volant, C. [CEA/Saclay, Dept. d' Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l' Instrumentation Associee (DAPNIA), 91 - Gif-sur-Yvette (France); Dufour, J.P. [CENBG, IN2P3, 33 - Gradignan (France)

    2000-07-01

    The spallation of {sup 197}Au by 800 MeV protons was investigated in inverse kinematics at GSI, Darmstadt, by use of a {sup 197}Au beam bombarding a liquid-hydrogen target. The fragment separator (FRS) was used to select and identify the reaction products prior to {beta} decay. The individual production cross sections and the kinematical properties of 396 isotopes for all elements between mercury (Z=80) and neodymium (Z=60) have been measured. A comparison with Monte Carlo calculations based on different two-step models of the spallation reaction is given. The shape of the isotopic distributions close to the projectile is found to differ strongly from that resulting from aluminium-induced fragmentation of {sup 197}Au. The mean kinetic energies of the fragments are deduced from the experimental data. The importance of the new data to improve our understanding of the spallation mechanism and the relevance for the design of accelerator-driven sub-critical reactors is discussed. (authors)

  7. Spallation and fission products in the (p+{sup 179}Hf) and (p+{sup nat}Hf) reactions

    Energy Technology Data Exchange (ETDEWEB)

    Karamian, S.A. [Joint Institute for Nuclear Research, Moscow Region, Dubna 141980 (Russian Federation); Ur, C.A. [Horia Hulubei National Institute of Physics and Nuclear Engineering, P.O. Box MG-6, Bucharest 077125 (Romania); Induced Gamma Emission Foundation, P.O. Box 34-81, Bucharest 010044 (Romania)], E-mail: ur@pd.infn.it; Adam, J. [Joint Institute for Nuclear Research, Moscow Region, Dubna 141980 (Russian Federation); Institute of Nuclear Physics, Rez, Prague CZ-25068 (Czech Republic); Kalinnikov, V.G.; Lebedev, N.A.; Vostokin, G.K. [Joint Institute for Nuclear Research, Moscow Region, Dubna 141980 (Russian Federation); Collins, C.B. [Center for Quantum Electronics, University of Texas at Dallas, Richardson, TX 75083 (United States); Popescu, I.I. [Induced Gamma Emission Foundation, P.O. Box 34-81, Bucharest 010044 (Romania)

    2009-03-01

    Production of Hf and Lu high-spin isomers has been experimentally studied in spallation reactions induced by intermediate energy protons. Targets of enriched {sup 179}Hf (91%) and {sup nat}Hf were bombarded with protons of energy in the range from 90 to 650 MeV provided by the internal beam of the Dubna Phasotron synchrocyclotron. The activation yields of the reaction products were measured by using the {gamma}-ray spectroscopy and radiochemistry methods. The production cross-sections obtained for the {sup 179m2}Hf, {sup 178m2}Hf and {sup 177m}Lu isomers are similar to the previously measured values from the spallation of Ta, Re and W targets. Therefore, the reactions involving emission of only a few nucleons, like (p,p'), (p,p'n) and (p,2pn), can transfer high enough angular momentum to the final residual nuclei with reasonable large cross-sections. A significant gain in the isomeric yields was obtained when enriched {sup 179}Hf targets were used. The mass distribution of the residual nuclei was measured over a wide range of masses and the fission-to-spallation ratio could be deduced as a function of the projectile energy. Features of the reaction mechanism are briefly discussed.

  8. Time-Reversal Invariance Violation in Neutron Scattering at Spallation Neutron Sources

    Science.gov (United States)

    Gudkov, Vladimir

    2014-09-01

    The Time Reversal Invariant Violating (TRIV) effects in neutron transmission through a nuclei target are discussed. We explore the possibility to search TRIV at new high flux Spallation Neutron Sources using two important advantages of neutron nuclei interactions: the possibility of an enhancement of T-violating observables by many orders of magnitude, and the relatively large number of the nuclear targets, which provides the assurance of avoiding possible ``accidental'' cancelations of TRI-violating effects due to unknown structural factors related to the strong interactions. This include the absence of final state interactions for a set of specific observables, the possibility to avoid of false asymmetries arising from combinations of time-reversal-invariant interactions and asymmetries in real experiment, and the comparison of expected results with existing limits on neutron, nuclear and atomic electric dipole moments (EDMs). It is shown that TRIV observables are complementary to the EDM experiments and have potential for essential improving of the current limits on the TRIV interactions. The Time Reversal Invariant Violating (TRIV) effects in neutron transmission through a nuclei target are discussed. We explore the possibility to search TRIV at new high flux Spallation Neutron Sources using two important advantages of neutron nuclei interactions: the possibility of an enhancement of T-violating observables by many orders of magnitude, and the relatively large number of the nuclear targets, which provides the assurance of avoiding possible ``accidental'' cancelations of TRI-violating effects due to unknown structural factors related to the strong interactions. This include the absence of final state interactions for a set of specific observables, the possibility to avoid of false asymmetries arising from combinations of time-reversal-invariant interactions and asymmetries in real experiment, and the comparison of expected results with existing limits on neutron

  9. Substrate-induced coagulation (SIC) of nano-disperse alumina in non-aqueous media: The dispersibility and stability of alumina in N-methyl-2-pyrrolidinone.

    Science.gov (United States)

    Basch, Angelika; Strnad, Simona

    2011-01-20

    This work investigated colloidal properties such as the zeta-potential, the electrophoretic mobilities and the wetting behaviour of alumina dispersed in non-aqueous media. Non-aqueous dispersions of alumina were prepared in the solvent N-methyl-2-pyrrolidinone (NMP). The wetting behaviour of alumina in NMP was characterized by the powder contact angle method and the Wilhemy plate method. The behaviour of the dispersion should provide information for the development of a substrate-induced coagulation (SIC) coating process of nano-sized alumina in non-aqeous media. SIC is a dip-coating process that coats pretreated but chemically different surfaces with nano-sized particles. It was found that the anionic surfactant dioctyl sulfosuccinate (AOT) had no stabilizing effect on alumina dispersed in NMP.

  10. Study of preparation and surface morphology of self-ordered nanoporous alumina; Estudo da preparacao e da morfologia de superficie de alumina nanoporosa auto-organizada

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Elisa Marchezini; Martins, Maximiliano Delany, E-mail: elisamarch@gmail.com, E-mail: MG.mdm@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG. (Brazil); Silva, Ronald Arreguy, E-mail: arregsilva@yahoo.com.br [Centro Universitario de Belo Horizonte (UniBH), Belo Horizonte, MG (Brazil)

    2013-07-01

    Nanoporous alumina is a typical material that exhibits self-ordered nanochannels spontaneously organized in hexagonal shape. Produced by anodizing of metallic aluminum, it has been used as a template for production of materials at the nanoscale. This work aimed to study the preparation of nanoporous alumina by anodic anodizing of metallic aluminum substrates. The nanoporous alumina was prepared following the methodology proposed by Masuda and Fukuda (1995), a two-step method consisting of anodizing the aluminum sample in the potentiostatic mode, removing the layer of aluminum oxide (alumina) formed and then repeat the anodization process under the same conditions as the first anodization. This method produces nanoporous alumina with narrow pore diameter distribution and well-ordered structure. (author)

  11. Catalyst materials based on plasma-processed alumina nanopowder

    Directory of Open Access Journals (Sweden)

    Dubencovs Konstantins

    2012-01-01

    Full Text Available A platinum catalyst for glycerol oxidation by molecular oxygen has been developed applying the extractive-pyrolytic method and using, as a support, a fine alumina powder with an average particle size of 30-60 nm processed by plasma technology. The extractive-pyrolytic method (EPM allows affixing small amounts of catalytic metals (1-5% with the particle size ranging from several nanometers to several tens of nanometers onto the surface of the support. The prepared material - 4.8 wt. % platinum on nano-sized alumina - can be used as a catalyst for glycerol oxidation by oxygen with conversion up to 84%, in order to produce some organic acids (glyceric and lactic acid with a selectivity of about 60%.

  12. Epitaxial growth of tungsten nanoparticles on alumina and spinel surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Suarez, T; Lopez-Esteban, S; Pecharroman, C; Esteban-Cubillo, A; Moya, J S [Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Cientificas (CSIC), C/ Sor Juana Ines de la Cruz 3, 28049, Cantoblanco, Madrid (Spain); Diaz, L A; Torrecillas, R [Nanomaterials and Nanotechnology Research Center (CINN), Consejo Superior de Investigaciones CientIficas (CSIC), C/ Francisco Pintado Fe 26, 33011, Oviedo, Asturias (Spain); Gremillard, L [Universite de Lyon, INSA-Lyon, MATEIS, UMR CNRS 5510, 20 avenue Albert Einstein, Villeurbanne F-69621 (France)], E-mail: jsmoya@icmm.csic.es

    2008-05-28

    Isolated tungsten nanoparticles ({alpha}-W and {beta}-W phase) were synthesized and epitaxially grown on alumina and spinel particle surfaces with an average tungsten size of {<=}20 nm for a low tungsten content (of {<=}1.5 vol%). Using tungsten (VI) ethoxide alcoholic solutions, tungsten trioxide hydrated precursors were attached to a ceramic grains surface as a nanoparticle coating. High-resolution transmission electron microscopy (HRTEM) micrographs showed epitaxial interfaces between alumina, spinel and metallic tungsten. This epitaxial growth is assumed to be due to the effect of water vapour on the sublimation of ortho-tungstic acid during the reduction process in a hydrogen atmosphere. The planes involved in the epitaxy were found to be (22-bar 0){sub Al2O3} parallel (121){sub W} and (311){sub MgAl2O4} parallel (110){sub W}.

  13. Melt processing of Bi--2212 superconductors using alumina

    Science.gov (United States)

    Holesinger, Terry G.

    1999-01-01

    Superconducting articles and a method of forming them, where the superconducting phase of an article is Bi.sub.2 Sr.sub.2 CaCu.sub.2 O.sub.y (Bi-2212). Alumina is combined with Bi-2212 powder or Bi-2212 precursor powder and, in order to form an intimate mixture, the mixture is melted and rapidly cooled to form a glassy solid. The glassy solid is comminuted and the resulting powder is combined with a carrier. An alternative to melting is to form the mixture of nanophase alumina and material having a particle size of less than about 10 microns. The powder, with the carrier, is melt processed to form a superconducting article.

  14. Preparation of zirconia-alumina powder by co-precipitation

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A zirconia-alumina powder with a near spherical shape and an average size of 0.1 ~ 0.2μm was prepared byco-precipitation. XRD analysis shows that α-Al2O3 phase may be directly transformed from amorphous in calcining the hydroxide composite. The ZrO2-Al2O3 composite ceramics manufactured from this powder has the maximum fracture toughness of 9 M Pa·m- 1/2 at 15 % ZrO2 and 740 MPa fracture strength at 5 % ZrO2. Zirconia grains about 1 μm in diameter aredispersed uniformly in the alumina ceramic matrix

  15. Measurements of prompt radiation induced conductivity of alumina and sapphire

    Energy Technology Data Exchange (ETDEWEB)

    Hartman, E. Frederick [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Zarick, Thomas Andrew [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sheridan, Timothy J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Preston, Eric F. [ITT Coporation, Colorado Springs, CO (United States)

    2011-04-01

    We performed measurements of the prompt radiation induced conductivity in thin samples of Alumina and Sapphire at the Little Mountain Medusa LINAC facility in Ogden, UT. Five mil thick samples were irradiated with pulses of 20 MeV electrons, yielding dose rates of 1E7 to 1E9 rad/s. We applied variable potentials up to 1 kV across the samples and measured the prompt conduction current. Analysis rendered prompt conductivity coefficients between 1E10 and 1E9 mho/m/(rad/s), depending on the dose rate and the pulse width for Alumina and 1E7 to 6E7 mho/m/(rad/s) for Sapphire.

  16. Alumina lightweight ceramics modified with plasma synthesized nanopowders

    Science.gov (United States)

    Zake, I.; Svinka, R.; Svinka, V.; Palcevskis, E.

    2011-12-01

    The aim of this study is to clarify possibilities of using plasma synthesized Al2O3 and SiC nanopowders as additives in alumina lightweight ceramics prepared by slip casting. Each plasma synthesized nanopowder (PSNP) was incorporated in the material by a different method, because of their diverse influence on the properties of slip. Al2O3 PSNP was introduced in the matrix in form of aqueous suspension. SiC nanopowder was added directly to raw materials. Bending strength, bulk density, apparent porosity and thermal shock resistance were determined to evaluate the influence of these additives. The effect of Al2O3 PSNP addition on the properties of material depends on the initial sintering temperature. SiC particles during sintering oxidize into SiO2 and then in the reaction with alumina form mullite. Addition of SiC considerably improves bending strength and thermal shock resistance.

  17. Synthesis of catalysts supported in {gamma}-alumina; Sintese de catalisadores suportados na {gamma}-alumina

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Luiza Gabriel; Silva, A.J.N.; Santos, I.M.G.; Souza, A.G. [Paraiba Univ, Joao Pessoa, PB (Brazil). Dept. de Quimica. Lab. de Termoquimica e Materiais]. E-mail: luizagaby@yahoo.com.br; Fernandes Junior, V.J.; Araujo, A.S. [Rio Grande do Norte Univ., Natal, RN (Brazil). Dept. de Quimica. Lab. de Combustiveis

    2003-07-01

    Fuels contain a great amount of undesirable pollutants as asphaltenes, metals, sulfides and nitrogen compounds. The content of sulfur in petroleum is around 1%,. When burned, fuels liberate SO{sub x}, the greatest air pollutant . The maximum sulfur quantity in diesel is {approx}350 wppm, but in agreement to European specifications, this content will fall to 50 wppm up to 2005. To remove this sulfur a deep hydrodesulfurization is necessary, requiring high performance catalysts. This way, in this work, the following catalysts were synthesized, using Pechini method: MoO{sub 3} containing Ni and/or Co supported on {gamma}-alumina, with the formulas Co{sub x}Mo{sub 1-x}O{sub 3}/Al{sub 2}O{sub 3}, Ni{sub x}Mo{sub 1-x}O{sub 3}/Al{sub 2}O{sub 3} and Ni{sub x/2}Co{sub x/2}Mo{sub 1-x}O{sub 3}/Al{sub 2}O{sub 3} where x 0,01, 0,02 and 0,03 in mol percentage. This method was proposed, due to its high stoichiometry control, purity, reproducibility and homogeneity. All catalysts were submitted to thermal treatment at 500 deg C to 700 deg C and characterized by thermogravimetry, infrared spectroscopy, X-ray diffraction. Results indicate the stabilization of the requested composition at around 622 deg C. The X-ray diffraction results indicate that secondary phase increases with dopant amount. (author)

  18. Ion irradiation effect of alumina and its luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Aoki, Yasushi; Yamamoto, Shunya; Naramoto, Hiroshi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; My, N.T.

    1997-03-01

    The luminescence spectra of single crystalline alpha-alumina and ruby which has 0.02% of Cr{sub 2}O{sub 3} as a impurity, induced by 200 keV He{sup +} and Ar{sup +} irradiation were measured at room temperature as a function of irradiation dose. The analysis of the measured spectra showed the existence of three main luminescence features in the wavelength region of 250 to 350 nm, namely anionic color centers, F-center at 411 nm and F{sup +}-center at 330 nm and a band observed around 315 nm. As alpha-alumina was irradiated with He{sup +}, F-center and F{sup +}-center luminescence grew and decayed, but the behaviors of those were different from each other. It seems that a concentration quenching occurred on the F-center luminescence in the dose range above 1x10{sup 14} He/cm{sup 2}. Furthermore, F-center luminescence was strongly suppressed in ruby, compared with that in alumina. On the other hand, the luminescence band around 315 nm appeared only in the early stage of irradiation and did not show its growth part. The dose dependent behavior was similar to that of Cr{sup 3+} emission at 695 nm (R-line) in ruby in both cases of He{sup +} and Ar{sup +} irradiation. Based on the experimental results mentioned above, the processes of defect formation and excitation in alumina in the early stage of ion irradiation will be discussed. (author)

  19. Results of recent KROTOS FCI tests. Alumina vs. corium melts

    Energy Technology Data Exchange (ETDEWEB)

    Huhtiniemi, I.; Magallon, D.; Hohmann, H. [Commission of the European Communities, Ispra (Italy). Joint Research Center

    1998-01-01

    Recent results from KROTOS fuel-coolant interaction experiments are discussed. Five tests with alumina were performed under highly subcooled conditions, all of these tests resulted in spontaneous steam explosions. Additionally, four tests were performed at low subcooling to confirm, on one hand, the suppression of spontaneous steam explosions under such conditions and, on the other hand, that such a system is still triggerable using an external initiator. The other test parameters in these alumina tests included the melt superheat and the initial pressure. All the tests in the investigated superheat range (150 K - 750 K) produced a steam explosion and no evidence of the explosion suppression by the elevated initial pressure (in the limited range of 0.1 - 0.375 MPa) was observed in the alumina tests. The corium test series include a test with 3 kg of melt under both subcooled and near saturated conditions at ambient pressure. Two additional tests were performed with subcooled water; one test was performed at an elevated pressure of 0.2 MPa with 2.4 kg of melt and another test with 5.1 kg of melt at ambient pressure. None of these tests with corium produced a propagating energetic steam explosion. However, propagating low energy (about twice the energy of the trigger pulse) events were observed. All corium tests produced significantly higher water level swells during the mixing phase than the corresponding alumina tests. Present experimental evidence suggests that the water depletion in the mixing zone suppresses energetic steam explosions with corium melts at ambient pressure and in the present pour geometry. Processes that could produce such a difference in void generation are discussed. (author)

  20. Friction and Wear of Sintered Alumina at High Temperature

    OpenAIRE

    Senda, Tetsuya; TAKAHASHl, Chiori; UEMATSU, Susumu; Amada, Shigeyasu

    1991-01-01

    The frictional behavior of alumina ceramics was investigated at various temperatures up to 1200℃. The coefficient of friction decreased with increasing temperature and this temperature dependency became more pronounced as higher contact pressures were applied. Wear loss at room temperature could be interpreted as being caused by one of either two different behavior modes. These have a rate difference of a factor of ten. At temperatures higher than 800℃, the wear loss was far less than that at...

  1. MICROWAVE JOINING OF ALUMINA CERAMIC AND HYDROXYLAPATITE BIOCERAMIC

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Microwave joining is a rapid developmental new techniqu e in recent years.This paper introduces a new microwave joining equipment which was made by our lab,succeeds in alumina ceramic-hydroxylapatite bioceramic j o in in the equipment, and analyzes the join situation of join boundary by using s canni ng electron microscope(SEM),this paper analyzes the mechanism of microwave joini ng also.

  2. Proton adsorption onto alumina: extension of multisite complexation (MUSIC) theory

    Energy Technology Data Exchange (ETDEWEB)

    Nagashima, K.; Blum, F.D.

    1999-09-01

    The adsorption isotherm of protons onto a commercial {gamma}-alumina sample was determined in aqueous nitric acid with sodium nitrate as a background electrolyte. Three discrete regions could be discerned in the log-log plots of the proton isotherm determined at the solution pH 5 to 2. The multisite complexation (MUSIC) model was modified to analyze the simultaneous adsorption of protons onto various kinds of surface species.

  3. Thin alumina and silica films by chemical vapor deposition (CVD)

    OpenAIRE

    Hofman, R.; Morssinkhof, R.W.J.; Fransen, T.; Westheim, J.G.F.; Gellings, P.J.

    1993-01-01

    Alumina and silica coatings have been deposited by MOCVD (Metal Organic Chemical Vapor Deposition) on alloys to protect them against high temperature corrosion. Aluminium Tri-lsopropoxide (ATI) and DiAcetoxyDitertiaryButoxySilane (DAOBS) have been used as metal organic precursors to prepare these ceramic coatings. The influence of several process steps on the deposition rate and surface morphology is discussed. The deposition of SiO2 at atmospheric pressure is kinetically limited below 833 K ...

  4. The EURISOL Multi Megawatt Target Station, a liquid metal target for a High Power spallation source.

    CERN Document Server

    Kharoua, C; Blumenfeld, L; Milenkovich, R; Wagner, W; Thomsen, K; Dementjevs, S; Platacis, E; Kravalis, K; Zik, A

    The European Isotope Separation On-Line Radioactive Ion Beam Facility (EURISOL) is set to be the ‘next-generation’ European Isotope Separation On-Line (ISOL) Radioactive Ion Beam (RIB) facility. It will extend and amplify current research in nuclear physics, nuclear astrophysics and fundamental interactions beyond the year 2013.In EURISOL, four target stations are foreseen, three direct targets of approximately 100 kW of beam power and one multi-MW liquid metal proton-to-neutron converter, all driven by a high-power particle accelerator. In the aforementioned multi-MW target assembly, high-intensity RIBs of neutron-rich isotopes will be obtained by inducing fission in several actinide targets surrounding a liquid metal spallation neutron source.This presentation summarises the work carried out for the Multi Megawatt target station of the EURISOL Design Study with particular attention to the coupled neutronic of the liquid converter and the overall performance of the facility, which will sustain fast neutr...

  5. High Field Pulsed Magnets for Neutron Scattering at the Spallation Neutron Source

    Science.gov (United States)

    Granroth, G. E.; Lee, J.; Fogh, E.; Christensen, N. B.; Toft-Petersen, R.; Nojiri, H.

    2015-03-01

    A High Field Pulsed Magnet (HFPM) setup, is in use at the Spallation Nuetron Source(SNS), Oak Ridge National Laboratory. With this device, we recently measured the high field magnetic spin structure of LiNiPO4. The results of this study will be highlighted as an example of possible measurements that can be performed with this device. To further extend the HFPM capabilities at SNS, we have learned to design and wind these coils in house. This contribution will summarize the magnet coil design optimization procedure. Specifically by varying the geometry of the multi-layer coil, we arrive at a design that balances the maximum field strength, neutron scattering angle, and the field homogeneity for a specific set of parameters. We will show that a 6.3kJ capacitor bank, can provide a magnetic field as high as 30T for a maximum scattering angle around 40° with homogeneity of +/- 4 % in a 2mm diameter spherical volume. We will also compare the calculations to measurements from a recently wound test coil. This work was supported in part by the Lab Directors' Research and Development Fund of ORNL.

  6. Fundamental neutron physics at a 1 MW long pulse spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Greene, G.L.

    1995-12-31

    Modern neutron sources and modern neutron science share a common origin in mid twentieth century scientific investigations concerned with the study of the fundamental interactions between elementary particles. Since the time of that common origin, neutron science and the study of elementary particles have evolved into quite disparate disciplines. The neutron became recognized as a powerful tool for the study of condensed matter with modern neutron sources being primarily used (and primarily justified) as tools for condensed matter research. The study of elementary particles has, of course, led to the development of rather different tools and is now dominated by activities carried out at extremely high energies. Notwithstanding this trend, the study of fundamental interactions using neutrons has continued and remains a vigorous activity at many contemporary neutron sources. This research, like neutron scattering research, has benefited enormously by the development of modern high flux neutron facilities. Future sources, particularly high power spallation sources, offer exciting possibilities for the continuation of this program of research.

  7. Cumulative beam break-up study of the spallation neutron source superconducting linac

    CERN Document Server

    Jeon, D; Krafft, G A; Yunn, B; Sundelin, R; Delayen, J; Kim, S; Doleans, M

    2002-01-01

    Beam instabilities due to High Order Modes (HOMs) are a concern to superconducting (SC) linacs such as the Spallation Neutron Source (SNS) linac. The effects of pulsed mode operation on transverse and longitudinal beam breakup instability are studied for H sup - beam in a consistent manner for the first time. Numerical simulation indicates that cumulative transverse beam breakup instabilities are not a concern in the SNS SC linac, primarily due to the heavy mass of H sup - beam and the HOM frequency spread resulting from manufacturing tolerances. As little as +-0.1 MHz HOM frequency spread stabilizes all the instabilities from both transverse HOMs, and also acts to stabilize the longitudinal HOMs. Such an assumed frequency spread of +-0.1 MHz HOM is small, and hence conservative compared with measured values of sigma=0.00109(f sub H sub O sub M -f sub 0)/f sub 0 obtained from Cornell and the Jefferson Lab Free Electron Laser cavities. However, a few cavities may hit resonance lines and generate a high heat lo...

  8. A Large Neutrino Detector Facility at the Spallation Neutron Source at Oak Ridge National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Efremenko, Y.V.

    1999-02-14

    The ORLaND (Oak Ridge Large Neutrino Detector) collaboration proposes to construct a large neutrino detector in an underground experimental hall adjacent to the first target station of the Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory. The main mission of a large (2000 ton) Scintillation-Cherenkov detector is to measure {bar {nu}}{sub {mu}} {r_arrow} {bar {nu}}{sub e} neutrino oscillation parameters more accurately than they can be determined in other experiments, or significantly extending the covered parameter space below (sin'20 {le} 10{sup {minus}4}). In addition to the neutrino oscillation measurements, ORLaND would be capable of making precise measurements of sin{sup 2} {theta}{sub W}, search for the magnetic moment of the muon neutrino, and investigate the anomaly in the KARMEN time spectrum, which has been attributed to a new neutral particle. With the same facility an extensive program of measurements of neutrino nucleus cross sections is also planned to support nuclear astrophysics.

  9. On the nucleon effective mass role to the high energy proton spallation reactions

    Energy Technology Data Exchange (ETDEWEB)

    Santos, B.M., E-mail: biank_ce@if.uff.br [Instituto de Física, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza, 24210-346 Niterói, RJ (Brazil); Instituto Militar de Engenharia, Praça General Tibúrcio 80, 22290-270 Rio de Janeiro, RJ (Brazil); Pinheiro, A.R.C. [Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, 22290-180 Rio de Janeiro, RJ (Brazil); Universidade Federal do Acre, BR 364 km 04, 69920-900 Rio Branco, AC (Brazil); Gonçalves, M. [Comissão Nacional de Energia Nuclear, Rua General Severiano 90, 22290-901 Rio de Janeiro, RJ (Brazil); Duarte, S.B. [Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, 22290-180 Rio de Janeiro, RJ (Brazil); Cabral, R.G. [Instituto Militar de Engenharia, Praça General Tibúrcio 80, 22290-270 Rio de Janeiro, RJ (Brazil)

    2016-04-15

    We explore the effect of the nucleon effective mass to the dynamic evolution of the rapid phase of proton–nucleus spallation reactions. The analysis of the relaxation time for the non-equilibrium phase is studied by variations in the effective mass parameter. We determine the final excitation energy of the hot residual nucleus at the end of cascade phase and the de-excitation of the nuclear system is carried out considering the competition of particle evaporation and fission processes. It was shown that the excitation energy depends of the hot compound residual nucleus at the end of the rapid phase on the changing effective mass. The multiplicity of particles was also analyzed in cascade and evaporation phase of the reaction. The use of nucleon effective mass during cascade phase can be considered as an effect of the many-body nuclear interactions not included explicitly in a treatment to the nucleon–nucleon interaction inside the nucleus. This procedure represents a more realistic scenario to obtain the neutron multiplicity generated in this reaction, which is a benchmark for the calculation of the neutronic in the ADS reactors.

  10. Improved design of proton source and low energy beam transport line for European Spallation Source

    Energy Technology Data Exchange (ETDEWEB)

    Neri, L., E-mail: neri@lns.infn.it; Celona, L.; Gammino, S.; Mascali, D.; Castro, G.; Ciavola, G. [Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare, Via S. Sofia 62, 95123 Catania (Italy); Torrisi, G. [Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare, Via S. Sofia 62, 95123 Catania (Italy); Dipartimento di Ingegneria dell’Informazione, delle Infrastrutture e dell’Energia Sostenibile, Università Mediterranea di Reggio Calabria, Via Graziella, 89122 Reggio Calabria (Italy); Cheymol, B.; Ponton, A. [European Spallation Source ESS AB, Lund (Sweden); Galatà, A. [Laboratori Nazionali di Legnaro, Istituto Nazionale di Fisica Nucleare, Viale dell' università 2, 35020 Legnaro (Italy); Patti, G. [Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare, Via S. Sofia 62, 95123 Catania (Italy); Laboratori Nazionali di Legnaro, Istituto Nazionale di Fisica Nucleare, Viale dell' università 2, 35020 Legnaro (Italy); Gozzo, A.; Lega, L. [Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare, Via S. Sofia 62, 95123 Catania (Italy); Dipartimento di Ingegneria Informatica e delle Telecomunicazioni, Università degli Studi di Catania, Viale Andrea Doria 6, 95123 Catania (Italy)

    2014-02-15

    The design update of the European Spallation Source (ESS) accelerator is almost complete and the construction of the prototype of the microwave discharge ion source able to provide a proton beam current larger than 70 mA to the 3.6 MeV Radio Frequency Quadrupole (RFQ) started. The source named PS-ESS (Proton Source for ESS) was designed with a flexible magnetic system and an extraction system able to merge conservative solutions with significant advances. The ESS injector has taken advantage of recent theoretical updates and new plasma diagnostics tools developed at INFN-LNS (Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare). The design strategy considers the PS-ESS and the low energy beam transport line as a whole, where the proton beam behaves like an almost neutralized non-thermalized plasma. Innovative solutions have been used as hereinafter described. Thermo-mechanical optimization has been performed to withstand the chopped beam and the misaligned focused beam over the RFQ input collimator; the results are reported here.

  11. Thermohydraulic behavior of the liquid metal target of a spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Y.

    1996-06-01

    The author presents work done on three main problems. (1) Natural circulation in double coaxial cylindircal container: The thermohydraulic behaviour of the liquid metal target of the spallation neutron source at PSI has been investigated. The configuration is a natural-circulation loop in a concentric double-tube-type container. The results show that the natural-circulation loop concept is valid for the design phase of the target construction, and the current specified design criteria will be fulfilled with the proposed parameter values. (2) Flow around the window: Water experiments were performed for geometry optimisation of the window shape of the SINQ container for avoiding generating recirculation zones at peripheral area and the optimal cooling of the central part of the beam entrance window. Flow visualisation technique was mainly used for various window shapes, gap distance between the window and the guide tube edge. (3) Flow in window cooling channels: Flows in narrow gaps of cooling channels of two different types of windows were studied by flow visualisation techniques. One type is a slightly curved round cooling channel and the other is hemispherical shape, both of which have only 2 mm gap distance and the water inlet is located on one side and flows out from the opposite side. In both cases, the central part of the flow area has lower velocity than peripheral area.

  12. Mercury target R&D for the Oak Ridge spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Haines, J.R.; DiStefano, J.; Farrell, K.; Gabriel, T.A. [Oak Ridge National Lab., TN (United States)] [and others

    1996-06-01

    The conceptual design for the Oak Ridge Spallation Neutron Source (ORSNS) incorporates liquid mercury as its reference target material. A flowing liquid target was selected mainly because of the increased power handling capability possible with the convective transport process. The major reasons for choosing mercury as the liquid target material are because it: (1) is a liquid at room temperature, (2) has good heat transport properties, and (3) has a high atomic number and mass density resulting in high neutron yield and source brightness. Since liquid targets are not widely utilized in presently operating accelerator targets and because of the challenges posed by the intense, pulsed thermal energy deposition ({approximately}20-100 kJ deposited during each 1-10 {mu}s pulse), considerable R&D is planned for the mercury target concept. The key feasibility issue that will be addressed in early R&D efforts are the effects of the thermal shock environment, which will include development and testing of approaches to mitigate these effects. Materials compatiblity and ES&H issues associated with the use of liquid mercury are also of major importance in early R&D efforts. A brief description of the mercury target design concept, results of initial evaluations of its performance characteristics, identification of its critical issues, and an outline of the R&D program aimed at addressing these issues will be presented.

  13. Improved design of proton source and low energy beam transport line for European Spallation Source

    Science.gov (United States)

    Neri, L.; Celona, L.; Gammino, S.; Mascali, D.; Castro, G.; Torrisi, G.; Cheymol, B.; Ponton, A.; Galatà, A.; Patti, G.; Gozzo, A.; Lega, L.; Ciavola, G.

    2014-02-01

    The design update of the European Spallation Source (ESS) accelerator is almost complete and the construction of the prototype of the microwave discharge ion source able to provide a proton beam current larger than 70 mA to the 3.6 MeV Radio Frequency Quadrupole (RFQ) started. The source named PS-ESS (Proton Source for ESS) was designed with a flexible magnetic system and an extraction system able to merge conservative solutions with significant advances. The ESS injector has taken advantage of recent theoretical updates and new plasma diagnostics tools developed at INFN-LNS (Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare). The design strategy considers the PS-ESS and the low energy beam transport line as a whole, where the proton beam behaves like an almost neutralized non-thermalized plasma. Innovative solutions have been used as hereinafter described. Thermo-mechanical optimization has been performed to withstand the chopped beam and the misaligned focused beam over the RFQ input collimator; the results are reported here.

  14. Optimizing moderator dimensions for neutron scattering at the spallation neutron source.

    Science.gov (United States)

    Zhao, J K; Robertson, J L; Herwig, Kenneth W; Gallmeier, Franz X; Riemer, Bernard W

    2013-12-01

    In this work, we investigate the effect of neutron moderator dimensions on the performance of neutron scattering instruments at the Spallation Neutron Source (SNS). In a recent study of the planned second target station at the SNS facility, we have found that the dimensions of a moderator play a significant role in determining its surface brightness. A smaller moderator may be significantly brighter over a smaller viewing area. One of the immediate implications of this finding is that for modern neutron scattering instrument designs, moderator dimensions and brightness have to be incorporated as an integrated optimization parameter. Here, we establish a strategy of matching neutron scattering instruments with moderators using analytical and Monte Carlo techniques. In order to simplify our treatment, we group the instruments into two broad categories: those with natural collimation and those that use neutron guide systems. For instruments using natural collimation, the optimal moderator selection depends on the size of the moderator, the sample, and the moderator brightness. The desired beam divergence only plays a role in determining the distance between sample and moderator. For instruments using neutron optical systems, the smallest moderator available that is larger than the entrance dimension of the closest optical element will perform the best (assuming, as is the case here that smaller moderators are brighter).

  15. Design of a horizontal neutron reflectometer for the European Spallation Source

    CERN Document Server

    Nekrassov, D; Lieutenant, K; Moulin, J -F; Strobl, M; Steitz, R

    2013-01-01

    A design study of a horizontal neutron reflectometer adapted to the general baseline of the long pulse European Spallation Source (ESS) is presented. The instrument layout comprises solutions for the neutron guide, high-resolution pulse shaping and beam bending onto a sample surface being so far unique in the field of reflectometry. The length of this instrument is roughly 55 m, enabling $\\delta \\lambda / \\lambda$ resolutions from 0.5% to 10%. The incident beam is focussed in horizontal plane to boost measurements of sample sizes of 1*1 cm{^2} and smaller with potential beam deflection in both downward and upward direction. The range of neutron wavelengths untilized by the instrument is 2 to 7.1 (12.2, ...) {\\AA}, if every (second, ...) neutron source ulse is used. Angles of incidence can be set between 0{\\deg} and 9{\\deg} with a total accessible q-range from 4*10^{-3} {\\AA}^{-1} up to 1 {\\AA}^{-1}. The instrument operates both in {\\theta}/{\\theta} (free liquid surfaces) and {\\theta}/2{\\theta} (solid/liquid, ...

  16. Investigations with Gaseous Electron Multipliers for use on the ISIS spallation neutron source

    Science.gov (United States)

    Duxbury, D.; Rhodes, N.; Schooneveld, E.; Spill, E.

    2012-01-01

    Several investigations have been undertaken to ascertain the suitability of gaseous electron multipliers (GEMs) for use as a neutron detector on the ISIS spallation neutron source. Our initial investigations focused purely on whether these devices could be operated at the elevated pressure of 3He and CF4 necessary for 1mm position resolution (2.6 bars of CF4). In fact we were able to operate the GEMs at suitable gains with 3.5 bars of CF4. However encouraging these results were, we found that the GEMs charged up over time, which we postulated was due to the kapton substrate. A similar problem was seen at the early stages of the development of the microstrip gas chamber (MSGC), a solution of which was to use the semiconducting glass Schott S8900 as the substrate. Therefore we focused our attention to the manufacture of a GEM structure on an S8900 substrate. Our first devices were manufactured from 1mm thick glass and exhibit gains in excess of 1 × 104 for a single GEM stage in an argon isobutane gas mixture, when illuminated with 55Fe x-rays. A small amount of charging under irradiation has been observed in a flowing gas mixture, but the GEMs quickly stabilise and track atmospheric conditions. Further measurements in a 3He:CF4 atmosphere will show how suited these devices are to the needs of ISIS.

  17. Fermilab Project X nuclear energy application: Accelerator, spallation target and transmutation technology demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Gohar, Yousry; /Argonne; Johnson, David; Johnson, Todd; Mishra, Shekhar; /Fermilab

    2011-04-01

    The recent paper 'Accelerator and Target Technology for Accelerator Driven Transmutation and Energy Production' and report 'Accelerators for America's Future' have endorsed the idea that the next generation particle accelerators would enable technological breakthrough needed for nuclear energy applications, including transmutation of waste. In the Fall of 2009 Fermilab sponsored a workshop on Application of High Intensity Proton Accelerators to explore in detail the use of the Superconducting Radio Frequency (SRF) accelerator technology for Nuclear Energy Applications. High intensity Continuous Wave (CW) beam from the Superconducting Radio Frequency (SRF) Linac (Project-X) at beam energy between 1-2 GeV will provide an unprecedented experimental and demonstration facility in the United States for much needed nuclear energy Research and Development. We propose to carry out an experimental program to demonstrate the reliability of the accelerator technology, Lead-Bismuth spallation target technology and a transmutation experiment of spent nuclear fuel. We also suggest that this facility could be used for other Nuclear Energy applications.

  18. The Nanoscale Ordered MAterials Diffractometer NOMAD at the Spallation Neutron Source SNS

    Energy Technology Data Exchange (ETDEWEB)

    Feygenson, Mikhail [ORNL; Carruth, John William [ORNL; Hoffmann, Ron [ORNL; Chipley, Kenneth King [ORNL; Neuefeind, Joerg C [ORNL

    2012-01-01

    The Nanoscale Ordered Materials Diffractometer (NOMAD) is neutron time-of-flight diffractometer designed to determine pair dist ribution functions of a wide range of materials ranging from short range ordered liquids to long range ordered crystals. Due to a large neutron flux provided by the Spallation Neutron Source SNS and a large detector coverage neutron count-rates exceed comparable instruments by one to two orders of magnitude. This is achieved while maintaining a relatively high momentum transfer resolution of a $\\delta Q/Q \\sim 0.8\\%$ FWHM (typical), and an achievable $\\delta Q/Q$ of 0.24\\% FWHM (best). The real space resolution is related to the maximum momentum transfer; A maximum momentum transfer of 50\\AA$^{-1}$ can be achieved routinely and the maximum momentum transfer given by the detector configuration and the incident neutron spectrum is 125 \\AA$^{-1}$. High stability of the source and the detector allow small contrast isotope experiments to be performed. A detailed description of the instrument is given and the results of experiments with standard samples are discussed.

  19. The Nanoscale Ordered MAterials Diffractometer NOMAD at the Spallation Neutron Source SNS

    Energy Technology Data Exchange (ETDEWEB)

    Neuefeind, Joerg, E-mail: neuefeindjc@ornl.gov [Neutron Scattering Science Directorate, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN 37831-6475 (United States); Feygenson, Mikhail; Carruth, John; Hoffmann, Ron; Chipley, Kenneth K. [Neutron Scattering Science Directorate, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN 37831-6475 (United States)

    2012-09-15

    The Nanoscale Ordered MAterials Diffractometer (NOMAD) is neutron time-of-flight diffractometer designed to determine pair distribution functions of a wide range of materials ranging from short range ordered liquids to long range ordered crystals. Due to a large neutron flux provided by the Spallation Neutron Source SNS and a large detector coverage neutron count-rates exceed comparable instruments by one to two orders of magnitude. This is achieved while maintaining a relatively high momentum transfer resolution of a {delta}Q/Q{approx}0.8% FWHM (typical), and a possible {delta}Q/Qof0.24% FWHM (best). The real space resolution is related to the maximum momentum transfer; a maximum momentum transfer of 50 Angstrom-Sign {sup -1} can be obtained routinely and the maximum momentum transfer given by the detector configuration and the incident neutron spectrum is 125 Angstrom-Sign {sup -1}. High stability of the source and the detector allow small contrast isotope experiments to be performed. A detailed description of the instrument is given and the results of experiments with standard samples are discussed.

  20. The Nanoscale Ordered MAterials Diffractometer NOMAD at the Spallation Neutron Source SNS

    Science.gov (United States)

    Neuefeind, Jörg; Feygenson, Mikhail; Carruth, John; Hoffmann, Ron; Chipley, Kenneth K.

    2012-09-01

    The Nanoscale Ordered MAterials Diffractometer (NOMAD) is neutron time-of-flight diffractometer designed to determine pair distribution functions of a wide range of materials ranging from short range ordered liquids to long range ordered crystals. Due to a large neutron flux provided by the Spallation Neutron Source SNS and a large detector coverage neutron count-rates exceed comparable instruments by one to two orders of magnitude. This is achieved while maintaining a relatively high momentum transfer resolution of a δQ/Q ˜0.8% FWHM (typical), and a possible δQ/Q of 0.24% FWHM (best). The real space resolution is related to the maximum momentum transfer; a maximum momentum transfer of 50 Å-1 can be obtained routinely and the maximum momentum transfer given by the detector configuration and the incident neutron spectrum is 125 Å. High stability of the source and the detector allow small contrast isotope experiments to be performed. A detailed description of the instrument is given and the results of experiments with standard samples are discussed.

  1. Microscopic Strain Mapping in Nanostructured and Microstructured Alumina-Titania Coatings Under 4-point Compressive and Tensile Bending

    Science.gov (United States)

    2010-06-01

    resistance, including resistance to build-up of deposits from sea salts; - Mechanical wear resistance; - Spallation / cracking / chipping resistance...indentation crack resistance, adhesion strength, spallation resistance against bend- and cut test, abrasive wear resistance, sliding wear resistance. XRD...this area are explicitly destructive and involve theoretical modeling of the strain fields accompanying material removal (e.g. hole drilling and

  2. Alumina Based 500 C Electronic Packaging Systems and Future Development

    Science.gov (United States)

    Chen, Liang-Yu

    2012-01-01

    NASA space and aeronautical missions for probing the inner solar planets as well as for in situ monitoring and control of next-generation aeronautical engines require high-temperature environment operable sensors and electronics. A 96% aluminum oxide and Au thick-film metallization based packaging system including chip-level packages, printed circuit board, and edge-connector is in development for high temperature SiC electronics. An electronic packaging system based on this material system was successfully tested and demonstrated with SiC electronics at 500 C for over 10,000 hours in laboratory conditions previously. In addition to the tests in laboratory environments, this packaging system has more recently been tested with a SiC junction field effect transistor (JFET) on low earth orbit through the NASA Materials on the International Space Station Experiment 7 (MISSE7). A SiC JFET with a packaging system composed of a 96% alumina chip-level package and an alumina printed circuit board mounted on a data acquisition circuit board was launched as a part of the MISSE7 suite to International Space Station via a Shuttle mission and tested on the orbit for eighteen months. A summary of results of tests in both laboratory and space environments will be presented. The future development of alumina based high temperature packaging using co-fired material systems for improved performance at high temperature and more feasible mass production will also be discussed.

  3. High strength alumina produced by direct coagulation casting

    Energy Technology Data Exchange (ETDEWEB)

    Baader, F.H.; Will, J.; Tieche, D. [Swiss Federal Institute of Technology, Zuerich (Switzerland)

    1995-09-01

    Direct Coagulation Casting is a new colloidal forming technique. Double layer stabilized, concentrated alumina suspensions are solidified by shifting the suspensions pH from 4 towards the isoelectric point at 9 using the in situ enzyme-catalyzed decomposition of urea. This reaction minimizes the repulsive forces between the suspended particles. The remaining, attractive Van der Waals forces form a stiff particle network. Suspensions with low viscosities (0.3 Pa*s, 59 vol%) were prepared at pH 4. Deagglomeration of the suspensions by ball milling reduced the agglomerate size below 5 pm. The coagulation kinetics could be influenced either by the urease concentration or by the suspension temperature. Process variables were established, providing long idle times, which allowed additional filtration and degassing steps. Coagulation was followed by drying and sintering, whereby densities of more than 3.97 g/cm{sup 3}, a 4-point bending strength of 685 MPa (HIPed) and a high reliablility (m = 40) for high purity alumina were achieved. DCC has the potential to improve the reliability of alumina components of complex shape, as well as to avoid expensive molding.

  4. Zirconia-alumina-nanodiamond composites with gemological properties

    Science.gov (United States)

    Díaz, Luis A.; Montes-Morán, Miguel A.; Peretyagin, Pavel Y.; Vladimirov, Yuriy G.; Okunkova, Anna; Moya, José S.; Torrecillas, Ramón

    2014-02-01

    Nanodiamonds have excellent mechanical and optical properties with a wide range of potential applications as a filler material for nanocomposites. Here, we present a new family of zirconia-alumina-nanodiamond composites using two main processing routes: (1) a colloidal method, and (2) power mixing homogenization. Composites with detonation nanodiamonds quantities ranging within 0.3-5 vol.% followed by a pulsed electrical current sintering at a temperature range from 1,200 to 1,500 °C have been analyzed, and a significant enhancement in mechanical properties, i.e., indentation hardness (16.17 GPa), fracture toughness (15.5 MPa m1/2), and bending strength (1,600 MPa), could be observed. To support these excellent properties, TEM, color, reflectivity, and Raman spectroscopy measurements were also carried out. The microstructure of the composites is very homogeneous with average grain sizes between 200 and 500 nm depending on the processing temperature. Two morphologies are present: (a) intergranular dispersion of alumina grains and nanodiamonds distributed along the grain boundaries of the ZrO2 matrix, and (b) intragranular nano-dispersion of ZrO2 particles with sizes 20-80 nm located inside the alumina grains. In the present article, we show, for the first time in the scientific literature, a continuous palette of gray color gradation of new ceramic materials of metalized colors (white index L* 98-40) for gemological applications.

  5. Nanocarbon-Coated Porous Anodic Alumina for Bionic Devices

    Directory of Open Access Journals (Sweden)

    Morteza Aramesh

    2015-08-01

    Full Text Available A highly-stable and biocompatible nanoporous electrode is demonstrated herein. The electrode is based on a porous anodic alumina which is conformally coated with an ultra-thin layer of diamond-like carbon. The nanocarbon coating plays an essential role for the chemical stability and biocompatibility of the electrodes; thus, the coated electrodes are ideally suited for biomedical applications. The corrosion resistance of the proposed electrodes was tested under extreme chemical conditions, such as in boiling acidic/alkali environments. The nanostructured morphology and the surface chemistry of the electrodes were maintained after wet/dry chemical corrosion tests. The non-cytotoxicity of the electrodes was tested by standard toxicity tests using mouse fibroblasts and cortical neurons. Furthermore, the cell–electrode interaction of cortical neurons with nanocarbon coated nanoporous anodic alumina was studied in vitro. Cortical neurons were found to attach and spread to the nanocarbon coated electrodes without using additional biomolecules, whilst no cell attachment was observed on the surface of the bare anodic alumina. Neurite growth appeared to be sensitive to nanotopographical features of the electrodes. The proposed electrodes show a great promise for practical applications such as retinal prostheses and bionic implants in general.

  6. Mullite/SiAlON/alumina composites by infiltration processing

    Energy Technology Data Exchange (ETDEWEB)

    Albano, M.P.; Scian, A.N. [Centro de Tecnologia de Recursos Minerales y Ceramica, Buenos Aires (Argentina)

    1997-01-01

    The formation of mullite/SiAlON/alumina composites was studied by infiltrating a SiAlON/alumina-base composite with two different solutions, followed by thermal treatment. The base composite was prepared from a mixture of tabular Al{sub 2}O{sub 3} grains, fume SiO{sub 2}, and aluminum powders. The mixture was pressed into test bars and nitrided in a nitrogen-gas (N{sub 2}) atmosphere at 1,480 C. The infiltrants were prehydrolyzed ethyl polysilicate solution and ethyl polysilicate-aluminum nitrate solution. The composites were infiltrated under vacuum, cured at 100 C, and precalcined in air at 700 C. This infiltration process was repeated several times to produce bars that had been subjected to multiple infiltrations, then the bars were calcined in a N{sub 2} atmosphere at 1,480 C to obtain mullite/SiAlON/alumina composites. The infiltration process increased the percentage of nitrogenous crystalline and mullite phases in the matrix; therefore, a decrease of the composite microporosity was observed. The infiltration increased the mechanical strength of the composites. Of the two composites, the one produced using prehydrolyzed ethyl polysilicate as the infiltrant had a higher mechanical strength, before and after being subjected to a severe thermal shock.

  7. Intensifying digestion of diaspore and separation of alumina and silica

    Institute of Scientific and Technical Information of China (English)

    李小斌; 彭志宏; 刘桂华; 周秋生

    2003-01-01

    It was found that there lies a linear relationship among the thermodynamic data of complicate inorganic compounds with similar components. A method for estimating the thermodynamic data of complicate compound and a thermodynamic database involving alumina production were developed. It was found that the alumina digestion rate of activated diasporic bauxite by means of heat field increased much due to the structure aberration, i.e, from perfect structure to unstable corundum. The results from thermodynamic calculation and experiments showed that it was feasible for desilication at atmospheric pressure, and the effects on equilibrium concentration of SiO2 included temperature, mole ratio of Na2O/Al2O3 (αk), caustic and Na+ concentration. The technology of desilication of green liquor at atmosphere and separation of alumina and silica in aluminate solution with high concentration were established. The reaction activity of compounds containing silica and the converting law among compounds were studied, and the prototype technology of desilication products by hydrotreatment was also developed.

  8. Formation process of a strong water-repellent alumina surface by the sol-gel method

    Energy Technology Data Exchange (ETDEWEB)

    Feng Libang, E-mail: lepond@hotmail.com [School of Mechatronic Engineering, Lanzhou Jiaotong University, 88 West Anning Road, Lanzhou 730070 (China); Li Hui; Song Yongfeng; Wang Yulong [School of Mechatronic Engineering, Lanzhou Jiaotong University, 88 West Anning Road, Lanzhou 730070 (China)

    2010-03-01

    A novel strong water-repellent alumina thin film is fabricated by chemically adsorbing stearic acid (STA) layer onto the porous and roughened aluminum film coated with polyethyleneimine (PEI). The formation process and the structure of the strong water-repellent alumina film are investigated by means of contact angle measurement and atomic force microscope (AFM). Results show that the water contact angles for the alumina films increase with the increase of the immersion time in the boiling water, and meanwhile, the roughness of the alumina films increases with the dissolution of the boehmite in the boiling water. Finally, the strong water-repellent film with a high water contact angle of 139.1 deg. is obtained when the alumina films have distinct roughened morphology with some papillary peaks and porous structure. Moreover, both the roughened structure and the hydrophobic materials of the STA endow the alumina films with the strong water-repellence.

  9. Formation process of a strong water-repellent alumina surface by the sol-gel method

    Science.gov (United States)

    Feng, Libang; Li, Hui; Song, Yongfeng; Wang, Yulong

    2010-03-01

    A novel strong water-repellent alumina thin film is fabricated by chemically adsorbing stearic acid (STA) layer onto the porous and roughened aluminum film coated with polyethyleneimine (PEI). The formation process and the structure of the strong water-repellent alumina film are investigated by means of contact angle measurement and atomic force microscope (AFM). Results show that the water contact angles for the alumina films increase with the increase of the immersion time in the boiling water, and meanwhile, the roughness of the alumina films increases with the dissolution of the boehmite in the boiling water. Finally, the strong water-repellent film with a high water contact angle of 139.1° is obtained when the alumina films have distinct roughened morphology with some papillary peaks and porous structure. Moreover, both the roughened structure and the hydrophobic materials of the STA endow the alumina films with the strong water-repellence.

  10. A Study on the Effect of Nano Alumina Particles on Fracture Behavior of PMMA

    Directory of Open Access Journals (Sweden)

    Arezou Sezavar

    2015-04-01

    Full Text Available In the current research, the role of nano-sized alumina on deformation and fracture mechanism of Poly Methyl Methacrylate (PMMA was investigated. For this purpose, PMMA matrix nanocomposite reinforced with different wt% of alumina (i.e., 5, 10 and 15 were fabricated using the compression molding technique. Tensile properties of produced nanocomposites were studied using Zwick Z250 apparatus at cross head speed of about 5 mm/min. In order to specify the role of alumina nanoparticles on deformation and fracture mechanism of PMMA, microscopic evaluation was performed using scanning electron microscope (SEM. The achieved results prove that tensile properties of PMMA depend on alumina wt%. For example, addition of 15 wt% alumina to PMMA causes an increase of about 25% modulus of elasticity. Micrographs taken from the fracture surface of PMMA and its nanocomposites show deformation and fracture mechanism of PMMA changes as alumina is added to it.

  11. IMPROVED CORROSION RESISTANCE OF ALUMINA REFRACTORIES

    Energy Technology Data Exchange (ETDEWEB)

    John P. Hurley; Patty L. Kleven

    2001-09-30

    The initial objective of this project was to do a literature search to define the problems of refractory selection in the metals and glass industries. The problems fall into three categories: Economic--What do the major problems cost the industries financially? Operational--How do the major problems affect production efficiency and impact the environment? and Scientific--What are the chemical and physical mechanisms that cause the problems to occur? This report presents a summary of these problems. It was used to determine the areas in which the EERC can provide the most assistance through bench-scale and laboratory testing. The final objective of this project was to design and build a bench-scale high-temperature controlled atmosphere dynamic corrosion application furnace (CADCAF). The furnace will be used to evaluate refractory test samples in the presence of flowing corrodents for extended periods, to temperatures of 1600 C under controlled atmospheres. Corrodents will include molten slag, steel, and glass. This test should prove useful for the glass and steel industries when faced with the decision of choosing the best refractory for flowing corrodent conditions.

  12. Comparative study on sintered alumina for ballistic shielding application; Estudo comparativo entre aluminas sinterizadas visando aplicacao em blindagem balistica

    Energy Technology Data Exchange (ETDEWEB)

    Melo, Francisco Cristovao Lourenco de; Goncalves, Diniz Pereira [Centro Tecnico Aeroespacial (CTA), Sao Jose dos Campos, SP (Brazil). Inst. de Aeronautica e Espaco

    1997-12-31

    This work presents a development of the armor made from special ceramic materials and kevlar. An experimental investigation was conducted to study the ballistic penetration resistance on three samples taken from sintered alumina: a commercial one and two formulations A and B made in IAE/CTA. The main differences between the two formulations was the grain size and bend resistance. The knowledge of the mechanisms during the penetration and perforation process allowed to apply a ductile composite laminate made form kevlar under the alumina to delay its rupture. The last ballistic test showed how a Weibull`s modulii and other mechanical properties are able to improve ballistic penetration resistance. (author) 3 refs.

  13. Effect of Heat Treatment of the Alumina Powder on the Microstructure and Properties of Coatings

    Directory of Open Access Journals (Sweden)

    Prozorova Mayya

    2015-01-01

    Full Text Available The alumina powder was treated at a high temperature (1000°C. Dense (porosity of less than 2%, solid (1280 ± 30 HV0.3 and wear-resistant coatings based on heat-treated alumina powder were obtained by a multi-chamber detonation sprayer on the steel substrate. The microstructure, microhardness and the wear resistance of the alumina coatings were investigated.

  14. The Effect of Alumina Dispersant Powder on the Workability of Chromia Based Refractory for IGCC Application

    Science.gov (United States)

    Ming, Zhao Jing; Xun, Yang Zheng; Hong, Hwang Kyu; Hwan, Park Sang

    2011-10-01

    The quality of refractory applied on IGCC is a key factor that affects the cost of production. The workability and microstructure of chromia based castable are varied by introducing different type of alumina dispersant powder, such as active alumina powder. In this study, three types of active alumina powder are added to improve the workability. It's proved that the specific surface area and particle size distribution of fine powders in matrix part greatly affect the flow values and microstructures.

  15. Anodic behaviour of oxidised Ni-Fe alloys in cryolite-alumina melts

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, Vivien, E-mail: v.singleton@student.unsw.edu.a [Centre for Electrochemical and Mineral Processing, School of Chemical Engineering, University of New South Wales, Sydney 2052 (Australia); Welch, Barry J. [Welbank Consulting Ltd., PO Box 207, Whitianga 3542 (New Zealand); Skyllas-Kazacos, Maria [Centre for Electrochemical and Mineral Processing, School of Chemical Engineering, University of New South Wales, Sydney 2052 (Australia)

    2011-01-01

    Nickel-iron alloys have been identified as promising inert anode candidates for the Hall-Heroult process. In this study, binary Ni-Fe alloys of various compositions were subjected to short-term galvanostatic electrolysis in a cryolite-alumina bath at 960 {sup o}C. Prior to electrolysis, the anodes were oxidised at 800 {sup o}C for 48 h, forming a protective scale. Fe{sub 2}O{sub 3}, Ni{sub x}Fe{sub 3-x}O{sub 4} and Ni{sub x}Fe{sub 1-x}O were identified as the major scale components using a combination of X-ray diffraction (XRD) analysis and energy dispersive X-ray spectroscopy (EDX). Anodes having Ni content of 50-65 wt% performed adequately during short-term electrolysis, operating at a steady potential of 3-3.5 V vs. AlF{sub 3}/Al. Overall, it was found that the pre-formed oxide scale was effective in reducing anode wear and fluoridation. In the absence of a pre-formed scale, anodes were shown to undergo appreciable internal corrosion and/or passivation due to metal fluoride formation. Analysis of the anodes following electrolysis was performed using XRD and electron microprobe analysis (EPMA).

  16. Viscosity of aqueous and cyanate ester suspensions containing alumina nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Lawler, Katherine [Iowa State Univ., Ames, IA (United States)

    2009-01-01

    The viscosities of both aqueous and cyanate ester monomer (BECy) based suspensions of alumina nanoparticle were studied. The applications for these suspensions are different: aqueous suspensions of alumina nanoparticles are used in the production of technical ceramics made by slip casting or tape casting, and the BECy based suspensions are being developed for use in an injection-type composite repair resin. In the case of aqueous suspensions, it is advantageous to achieve a high solids content with low viscosity in order to produce a high quality product. The addition of a dispersant is useful so that higher solids content suspensions can be used with lower viscosities. For BECy suspensions, the addition of nanoparticles to the BECy resin is expected to enhance the mechanical properties of the cured composite. The addition of saccharides to aqueous suspensions leads to viscosity reduction. Through DSC measurements it was found that the saccharide molecules formed a solution with water and this resulted in lowering the melting temperature of the free water according to classic freezing point depression. Saccharides also lowered the melting temperature of the bound water, but this followed a different rule. The shear thinning and melting behaviors of the suspensions were used to develop a model based on fractal-type agglomeration. It is believed that the structure of the particle flocs in these suspensions changes with the addition of saccharides which leads to the resultant viscosity decrease. The viscosity of the BECy suspensions increased with solids content, and the viscosity increase was greater than predicted by the classical Einstein equation for dilute suspensions. Instead, the Mooney equation fits the viscosity behavior well from 0-20 vol% solids. The viscosity reduction achieved at high particle loadings by the addition of benzoic acid was also investigated by NMR. It appears that the benzoic acid interacts with the surface of the alumina particle which may

  17. Electromotive force measurements on cells involving beta-alumina solid electrolyte

    Science.gov (United States)

    Choudhury, N. S.

    1973-01-01

    Open-circuit emf measurements have been made to demonstrate that a two-phase, polycrystalline mixture of beta-alumina and alpha-alumina could be used as a solid electrolyte in galvanic cells with reversible electrodes fixing oxygen or aluminum chemical potentials. These measurements indicate that such a two-phase solid electrolyte may be used to monitor oxygen chemical potentials as low as that corresponding to Al and Al2O3 coexistence (potentials of about 10 to the minus 47th power atm at 1000 K). The activity of Na2O in beta-alumina in coexistence with alpha-alumina was also determined by emf measurements.

  18. The effect of alumina nanofillers size and shape on mechanical behavior of PMMA matrix composite

    Directory of Open Access Journals (Sweden)

    Ben Hasan Somaya Ahmed

    2014-01-01

    Full Text Available Composites with the addition of alumina nanofillers show improvement in mechanical properties. The PMMA polymer was used as a matrix and two different types of nanofillers, having extremely different shapes were added in the matrix to form the composite. Reinforcements were based on alumina nanoparticles having either spherical shape or whiskers having the length to diameter ratio of 100. The influence of alumina fillers size, shape and fillers loading on mechanical properties of prepared composite were studied using the nanoindentation measurements and dynamic mechanical analysis. It was observed that both alumina whiskers and alumina spherical nanoparticles added in the PMMA matrix improved the mechanical properties of the composite but the improvement was significantly higher with alumina whisker reinforcement. The concentration of the reinforcing alumina spherical nanoparticles and alumina whiskers in PMMA matrix varied up to 5 wt. %. The best performance was obtained by the addition of 3 wt. % of alumina whiskers in the PMMA matrix with regard to mechanical properties of the obtained composite.

  19. High field matching effects in superconducting Nb porous arrays catalyzed from anodic alumina templates

    DEFF Research Database (Denmark)

    Vinckx, W.; Vanacken, J.; Moshchalkov, V.V.;

    2007-01-01

    Vortex pinning in a superconducting Nb thin film deposited on an anodically grown alumina template is investigated. Anodic oxidation of aluminium layers permits under specific conditions the formation of highly ordered porous alumina, a membrane-like structure consisting of triangular arrays...... of parallel pores. Its pore diameter and interpore distance are set by careful tuning of the anodization parameters. A superconducting Nb thin film is deposited directly onto the alumina film. The porous alumina acts as a template and it allows Nb to form a periodic pinning array during its growth. Pinning...

  20. On the possibility of producing alumina ceramic with a slight electrical conductivity

    CERN Document Server

    Caspers, Fritz

    1989-01-01

    Antistatic alumina ceramic is desirable for certain particle accelerator applications. In general, highly insulating surface close to a charged particle beam must be avoided in order to prevent the formation of ion pockets and other unwanted electrical effects. For the AA vacuum chamber (UHV), an antistatic ferrite has been produced and successfully installed. The fabrication of antistatic alumina might be possible in a similar way. By using certain metal oxides in the cement, which holds the alumina particles together, a slight conductivity could be obtained after the firing and sintering process, without deteriorating the mechanical and outgassing properties of the alumina compound.

  1. Production of Actinium-225 via High Energy Proton Induced Spallation of Thorium-232

    Energy Technology Data Exchange (ETDEWEB)

    Harvey, James T.; Nolen, Jerry; Vandergrift, George; Gomes, Itacil; Kroc, Tom; Horwitz, Phil; McAlister, Dan; Bowers, Del; Sullivan, Vivian; Greene, John

    2011-12-30

    The science of cancer research is currently expanding its use of alpha particle emitting radioisotopes. Coupled with the discovery and proliferation of molecular species that seek out and attach to tumors, new therapy and diagnostics are being developed to enhance the treatment of cancer and other diseases. This latest technology is commonly referred to as Alpha Immunotherapy (AIT). Actinium-225/Bismuth-213 is a parent/daughter alpha-emitting radioisotope pair that is highly sought after because of the potential for treating numerous diseases and its ability to be chemically compatible with many known and widely used carrier molecules (such as monoclonal antibodies and proteins/peptides). Unfortunately, the worldwide supply of actinium-225 is limited to about 1,000mCi annually and most of that is currently spoken for, thus limiting the ability of this radioisotope pair to enter into research and subsequently clinical trials. The route proposed herein utilizes high energy protons to produce actinium-225 via spallation of a thorium-232 target. As part of previous R and D efforts carried out at Argonne National Laboratory recently in support of the proposed US FRIB facility, it was shown that a very effective production mechanism for actinium-225 is spallation of thorium-232 by high energy proton beams. The base-line simulation for the production rate of actinium-225 by this reaction mechanism is 8E12 atoms per second at 200 MeV proton beam energy with 50 g/cm2 thorium target and 100 kW beam power. An irradiation of one actinium-225 half-life (10 days) produces {approx}100 Ci of actinium-225. For a given beam current the reaction cross section increases slightly with energy to about 400 MeV and then decreases slightly for beam energies in the several GeV regime. The object of this effort is to refine the simulations at proton beam energies of 400 MeV and above up to about 8 GeV. Once completed, the simulations will be experimentally verified using 400 MeV and 8 Ge

  2. PENGARUH PERBEDAAN SIFAT PENYANGGA ALUMINA TERHADAP SIFAT KATALIS HYDROTREATING BERBASIS NIKEL-MOLIBDENUM

    Directory of Open Access Journals (Sweden)

    Maria Ulfah

    2012-11-01

    Full Text Available EFFECT OF ALUMINA SUPPORT PROPERTIES ON THE NICKEL-MOLIBDENUM BASE HYDROTREATING CATALYST. Effect of surface characteristics of three species of synthesized γ-alumina (alumina-1, alumina-2 and alumina-3 on characteristics NiMo catalysts has been studied. Those aluminas are derived from boehmite Catapal B by varying rasio mol nitric acid to boehmite. A sol-gel method is used to synthesize γ-Al2O3 support. The Nitrogen adsorption, X-ray diffraction (XRD, Temperature Programmed Reduction (TPR of H2, Temperature Programmed Desorption (TPD of NH3, and mechanical strength are used to characterize the supports and catalysts. The results showed that the surface area alumina affects the formation of crystalline MoO3 in the NiMo catalyst, while γ-Al2O3-3 support which has the highest surface area (about 195 m2/g compared to the other two types of alumina (>195 m2/g does not have a crystalline MoO3. The formation of crystalline MoO3 is not influenced by the acidity alumina. Based on the results of XRD, it is  indicated that the supported alumina-3 NiMo catalyst (having the highest acid strength shows that there is no presence of crystalline MoO3. Pore size distribution of support did not change significantly after the deposition of Ni and Mo oxides. Mechanical strength of support also affects the strength NiMo catalyst. Support alumina-3 which has the highest mechanical strength gives the mechanical strength of the highest NiMo catalyst. Pengaruh sifat penyangga γ-alumina hasil pengembangan (alumina-1, alumina-2 dan alumina-3 pada karakter katalis hydrotreating nikel-molibdenum (NiMo telah dipelajari. Ketiga jenis γ-alumina diturunkan dari boehmite “Catapal B” dengan menvariasikan nisbah mol asam nitrat terhadap boehmite. Pembuatan γ-alumina menggunakan metoda sol-gel. Adsorpsi Nitrogen, X-ray difraksi (XRD, Temperature Programmed Reduction (TPR H2, Temperature Programmed Desorption (TPD NH3, dan kekuatan mekanik digunakan untuk

  3. Viscosity of aqueous and cyanate ester suspensions containing alumina nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Lawler, Katherine [Iowa State Univ., Ames, IA (United States)

    2009-01-01

    The viscosities of both aqueous and cyanate ester monomer (BECy) based suspensions of alumina nanoparticle were studied. The applications for these suspensions are different: aqueous suspensions of alumina nanoparticles are used in the production of technical ceramics made by slip casting or tape casting, and the BECy based suspensions are being developed for use in an injection-type composite repair resin. In the case of aqueous suspensions, it is advantageous to achieve a high solids content with low viscosity in order to produce a high quality product. The addition of a dispersant is useful so that higher solids content suspensions can be used with lower viscosities. For BECy suspensions, the addition of nanoparticles to the BECy resin is expected to enhance the mechanical properties of the cured composite. The addition of saccharides to aqueous suspensions leads to viscosity reduction. Through DSC measurements it was found that the saccharide molecules formed a solution with water and this resulted in lowering the melting temperature of the free water according to classic freezing point depression. Saccharides also lowered the melting temperature of the bound water, but this followed a different rule. The shear thinning and melting behaviors of the suspensions were used to develop a model based on fractal-type agglomeration. It is believed that the structure of the particle flocs in these suspensions changes with the addition of saccharides which leads to the resultant viscosity decrease. The viscosity of the BECy suspensions increased with solids content, and the viscosity increase was greater than predicted by the classical Einstein equation for dilute suspensions. Instead, the Mooney equation fits the viscosity behavior well from 0-20 vol% solids. The viscosity reduction achieved at high particle loadings by the addition of benzoic acid was also investigated by NMR. It appears that the benzoic acid interacts with the surface of the alumina particle which may

  4. Design, status and first operations of the spallation neutron source polyphase resonant converter modulator system

    Energy Technology Data Exchange (ETDEWEB)

    Reass, W. A. (William A.); Apgar, S. E. (Sean E.); Baca, D. M. (David M.); Doss, James D.; Gonzales, J. (Jacqueline); Gribble, R. F. (Robert F.); Hardek, T. W. (Thomas W.); Lynch, M. T. (Michael T.); Rees, D. E. (Daniel E.); Tallerico, P. J. (Paul J.); Trujillo, P. B. (Pete B.); Anderson, D. E. (David E.); Heidenreich, D. A. (Dale A.); Hicks, J. D. (Jim D.); Leontiev, V. N.

    2003-01-01

    The Spallation Neutron Source (SNS) is a new 1.4 MW average power beam, 1 GeV accelerator being built at Oak Ridge National Laboratory. The accelerator requires 15 converter-modulator stations each providing between 9 and 11 MW pulses with up to a 1 .I MW average power. The converter-modulator can be described as a resonant 20 kHz polyphase boost inverter. Each converter modulator derives its buss voltage from a standard substation cast-core transformer. Each substation is followed by an SCR pre-regulator to accommodate voltage changes from no load to full load, in addition to providing a soft-start function. Energy storage is provided by self-clearing metallized hazy polypropylene traction capacitors. These capacitors do not fail short, but clear any internal anomaly. Three 'H-Bridge' IGBT transistor networks are used to generate the polyphase 20 kHz transformer primary drive waveforms. The 20 kHz drive waveforms are time-gated to generate the desired klystron pulse width. Pulse width modulation of the individual 20 lcHz pulses is utilized to provide regulated output waveforms with DSP based adaptive feedforward and feedback techniques. The boost transformer design utilizes nanocrystalline alloy that provides low core loss at design flux levels and switching frequencies. Capacitors are used on the transformer secondary networks to resonate the leakage inductance. The transformers are wound for a specific leakage inductance, not turns ratio. This design technique generates multiple secondary volts per turn as compared to the primary. With the appropriate tuning conditions, switching losses are minimized. The resonant topology has the added benefit of being deQed in a klystron fault condition, with little energy deposited in the arc. This obviates the need of crowbars or other related networks. A review of these design parameters, operational performance, production status, and OWL installation and performance to date will be presented.

  5. Structural design study of a proton beam window for a 1-MW spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Teraoku, Takuji; Terada, Atsuhiko; Maekawa, Fujio; Meigo, Shin-ichiro; Kaminaga, Masanori; Ishikura, Syuichi; Hino, Ryutaro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-03-01

    A 1-MW spallation neutron source aiming at materials and life science researches will be constructed under the JAERI-KEK High-intensity Proton Accelerator Project (J-PARC). A proton beam passes through a proton beam window, and be injected into a target of the neutron source. The proton beam window functions as a boundary wall between a high vacuum area in the proton beam line and a helium atmosphere at about atmospheric pressure in a helium vessel which contains the target and moderators. The proton beam window is cooled by light water because high heat-density is generated in the window material by interactions with the proton beam. Then, uniformity of the water flow is requested at the window to suppress a hot-spot that causes excessive thermal stress and cooling water boiling. Also, the window has to be strong enough in its structure for inner stress due to water pressure and thermal stress due to heat generation. In this report, we propose two types of proton beam windows; one flat-type that is easy to manufacture, and the other, curved-type that has high stress resistivity. As a part of design study for the windows, evaluation of strength of structure and thermal hydraulic analysis were conducted. As a result, it was found that sufficient heat removal was assured with uniform water flow at the window, and stress caused by internal water pressure and thermal stress could be maintained below allowable stress values. Accordingly, it was confirmed that the proton beam window designs were feasible. (author)

  6. Conceptual moderator studies for the Spallation Neutron Source short-pulse second target station.

    Science.gov (United States)

    Gallmeier, F X; Lu, W; Riemer, B W; Zhao, J K; Herwig, K W; Robertson, J L

    2016-06-01

    Candidate moderator configurations for a short-pulse second target station (STS) at the Oak Ridge National Laboratory Spallation Neutron Source (SNS) have been identified using a global optimizer framework built around the MCNPX particle transport code. Neutron brightness metrics were selected as the figure-of-merit. We assumed that STS would use one out of six proton pulses produced by an SNS accelerator upgraded to operate at 1.3 GeV proton energy, 2.8 MW power and 60 Hz repetition rate. The simulations indicate that the peak brightness can be increased by a factor of 5 and 2.5 on a per proton pulse basis compared to the SNS first target station for both coupled and decoupled para-hydrogen moderators, respectively. Additional increases by factors of 3 and 2 were demonstrated for coupled and decoupled moderators, respectively, by reducing the area of neutron emission from 100 × 100 mm(2) to 20 × 20 mm(2). This increase in brightness has the potential to translate to an increase of beam intensity at the instruments' sample positions even though the total neutron emission of the smaller moderator is less than that of the larger. This is especially true for instruments with small samples (beam dimensions). The increased fluxes in the STS moderators come at accelerated poison and de-coupler burnout and higher radiation-induced material damage rates per unit power, which overall translate into lower moderator lifetimes. A first effort was undertaken to group decoupled moderators into a cluster collectively positioning them at the peak neutron production zone in the target and having a three-port neutron emission scheme that complements that of a cylindrical coupled moderator.

  7. Thermal hydraulic design and decay heat removal of a solid target for a spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Takenaka, N. [Department of Mechanical Engineering, Kobe University, Kobe (Japan)]. E-mail: takenaka@mech.kobe-u.ac.jp; Nio, D. [Hokkaido University, Sapporo (Japan); Kiyanagi, Y. [Hokkaido University, Sapporo (Japan); Mishima, K. [Kyoto University Research Reactor Institute, Kumatori (Japan); Kawai, M. [High Energy Accelerator Research Institute, Tsukuba (Japan); Furusaka, M. [High Energy Accelerator Research Institute, Tsukuba (Japan)

    2005-08-01

    Thermal hydraulic design and thermal stress calculations were conducted for a water-cooled solid target irradiated by a MW-class proton beam for a spallation neutron source. Plate type and rod bundle type targets were examined. The thickness of the plate and the diameter of the rod were determined based on the maximum and the wall surface temperature. The thermal stress distributions were calculated by a finite element method (FEM). The neutronics performance of the target is roughly proportional to its average density. The averaged densities of the designed targets were calculated for tungsten plates, tantalum-clad tungsten plates, tungsten rods sheathed by tantalum and Zircaloy and they were compared with mercury density. It was shown that the averaged density was highest for the tungsten plates and was high for the tantalum cladding tungsten plates, the tungsten rods sheathed by tantalum and Zircaloy in order. They were higher than or equal to that of mercury for the 1-2 MW proton beams. Tungsten target without the cladding or the sheath is not practical due to corrosion by water under irradiation condition. Therefore, the tantalum cladding tungsten plate already made successfully by HIP and the sheathed tungsten rod are the candidate of high performance solid targets. The decay heat of each target was calculated. It was low enough low compared to that of ISIS for the target without tantalum but was about four times as high as that of ISIS when the thickness of the tantalum cladding was 0.5 mm. Heat removal methods of the decay heat with tantalum were examined. It was shown that a special cooling system was required for the target exchange when tantalum was used for the target. It was concluded that the tungsten rod target sheathed with stainless steel or Zircaloy was the most reliable from the safety considerations and had similar neutronics performance to that of mercury.

  8. Analysis of radiation environmental safety for China's Spallation Neutron Source (CSNS)

    Science.gov (United States)

    Wang, Qing-Bin; Wu, Qing-Biao; Ma, Zhong-Jian; Zhang, Qing-Jiang; Li, Nan; Wu, Jing-Min; Liu, Jian; Zhang, Gang

    2010-07-01

    The China Spallation Neutron Source (CSNS) is going to be located in Dalang Town, Dongguan City in the Guangdong Province. In this paper we report the results of the parameters related with environment safety based on experiential calculations and Monte Carlo simulations. The main project of the accelerator is an under ground construction. On top there is a 0.5 m concrete and 5.0 m soil covering for shielding, which can reduce the dose out of the tunnel's top down to 0.2 μSv/h. For the residents on the boundary of the CSNS, the dose produced by skyshine, which is caused by the penetrated radiation leaking from the top of the accelerator, is no more than 0.68 μSv/a. When CSNS is operating normally, the maximal annual effective dose due to the emission of gas from the tunnel is 2.40×10-3 mSv/a to the public adult, and 2.29×10-3 mSv/a to a child, both values are two orders of magnitude less than the limiting value for control and management. CSNS may give rise to an activation of the soil and groundwater in the nearest tunnels, where the main productions are 3H, 7Be, 22Na, 54Mn, etc. But the specific activity is less than the exempt specific activity in the national standard GB13376-92. So it is safe to say that the environmental impact caused by the activation of soil and groundwater is insignificant. To sum up, for CSNS, as a powerful neutron source device, driven by a high-energy high-current proton accelerator, a lot of potential factors affecting the environment exist. However, as long as effective shieldings for protection are adopted and strict rules are drafted, the environmental impact can be kept under control within the limits of the national standard.

  9. Conceptual moderator studies for the Spallation Neutron Source short-pulse second target station

    Science.gov (United States)

    Gallmeier, F. X.; Lu, W.; Riemer, B. W.; Zhao, J. K.; Herwig, K. W.; Robertson, J. L.

    2016-06-01

    Candidate moderator configurations for a short-pulse second target station (STS) at the Oak Ridge National Laboratory Spallation Neutron Source (SNS) have been identified using a global optimizer framework built around the MCNPX particle transport code. Neutron brightness metrics were selected as the figure-of-merit. We assumed that STS would use one out of six proton pulses produced by an SNS accelerator upgraded to operate at 1.3 GeV proton energy, 2.8 MW power and 60 Hz repetition rate. The simulations indicate that the peak brightness can be increased by a factor of 5 and 2.5 on a per proton pulse basis compared to the SNS first target station for both coupled and decoupled para-hydrogen moderators, respectively. Additional increases by factors of 3 and 2 were demonstrated for coupled and decoupled moderators, respectively, by reducing the area of neutron emission from 100 × 100 mm2 to 20 × 20 mm2. This increase in brightness has the potential to translate to an increase of beam intensity at the instruments' sample positions even though the total neutron emission of the smaller moderator is less than that of the larger. This is especially true for instruments with small samples (beam dimensions). The increased fluxes in the STS moderators come at accelerated poison and de-coupler burnout and higher radiation-induced material damage rates per unit power, which overall translate into lower moderator lifetimes. A first effort was undertaken to group decoupled moderators into a cluster collectively positioning them at the peak neutron production zone in the target and having a three-port neutron emission scheme that complements that of a cylindrical coupled moderator.

  10. R&D of A MW-class solid-target for a spallation neutron source

    Science.gov (United States)

    Kawai, Masayoshi; Furusaka, Michihiro; Kikuchi, Kenji; Kurishita, Hiroaki; Watanabe, Ryuzo; Li, Jing-Feng; Sugimoto, Katsuhisa; Yamamura, Tsutomu; Hiraoka, Yutaka; Abe, Katsunori; Hasegawa, Akira; Yoshiie, Masatoshi; Takenaka, Hiroyuki; Mishima, Katsuichiro; Kiyanagi, Yoshiaki; Tanabe, Tetsuo; Yoshida, Naoaki; Igarashi, Tadashi

    2003-05-01

    R&D for a MW-class solid target composed of tungsten was undertaken to produce a pulsed intense neutron source for a future neutron scattering-facility. In order to solve the corrosion of tungsten, tungsten target blocks were clad with tantalum by means of HIP'ing, brazing and electrolytic coating in a molten salt bath. The applicability of the HIP'ing method was tested through fabricating target blocks for KENS (spallation neutron source at KEK). A further investigation to certify the optimum HIP conditions was made with the small punch test method. The results showed that the optimum temperature was 1500 °C at which the W/Ta interface gave the strongest fracture strength. In the case of the block with a hole for thermocouple, it was found that the fabrication preciseness of a straight hole and a tantalum sheath influenced the results. The development of a tungsten stainless-steel alloy was tried to produce a bare tungsten target, using techniques in powder metallurgy. Corrosion tests for various tungsten alloys were made while varying the water temperature and velocity. The mass loss of tungsten in very slow water at 180 °C was as low as 0.022 mg/y, but increased remarkably with water velocity. Simulation experiments for radiation damage to supplement the STIP-III experiments were made to investigate material hardening by hydrogen and helium, and microstructures irradiated by electrons. Both experiments showed consistent results on the order of the dislocation numbers and irradiation hardness among the different tungsten materials. Thermal-hydraulic designs were made for two types of solid target system of tungsten: slab and rod geometry as a function of the proton beam power. The neutronic performance of a solid target system was compared with that of mercury target based on Monte Carlo calculations by using the MCNP code.

  11. Macroporous silica–alumina composites with mesoporous walls

    Indian Academy of Sciences (India)

    Gautam Gundiah

    2001-04-01

    Macroporous silica–alumina composites with mesopores have been prepared by employing polymethylmethacrylate beads as templates in the presence of the cationic surfactant, N-cetyl-N,N,N-trimethylammonium bromide. The Si/Al ratio in the composites has been varied between 4.5 and 48 and the occurrence of mesopores has been verified by X-ray diffraction. The surface areas of the samples vary between 676 and 1038 m2g–1, with the highest value in the sample with Si/Al = 48.

  12. Optical properties of porous anodic alumina embedded Cu nanocomposite films

    Science.gov (United States)

    Liu, Huiyuan; Sun, Huiyuan; Liu, Lihu; Hou, Xue; Jia, Xiaoxuan

    2015-06-01

    Porous anodic alumina embedded Cu with iridescent colors were fabricated in copper sulfate electrolyte. The films display highly saturated colors after being synthesized by an ac electrodeposition method. Tunable color in the films is obtained by adjusting anodization time, and can be adjusted across the entire visible range. Theoretical results of the changes in the structural color according to the Bragg-Snell formula are consistent with the experimental results. The films could be used in many areas including decoration, display and multifunctional anti-counterfeiting applications.

  13. Toughening and strengthening mechanism of zirconia-alumina multiphase ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Yu, M.Q.; Fan, S.G. [Research Inst. of Synthetic Crystals, Beijing, BJ (China); Shen, Q.; Zhang, L.M. [Wuhan Univ. of Technology (China)

    2003-07-01

    In the present study, the effect of compositions on the mechanical properties of zirconia-alumina multiphase ceramics was studied. The results showed that with the variety of ZrO{sub 2} content, the change of bending strength and fracture toughness of the multiphase ceramics exhibited a saddle shape which could be divided into three zones: ZTA, ADZ, and Transition zone. The mechanism of toughening and strengthening in each zone was mainly analyzed, and it was found that stress-induced transformation toughening of ZrO{sub 2} and dispersion strengthening of Al{sub 2}O{sub 3} were the two main factors. (orig.)

  14. Development of technology and applications based on porous alumina nanostructures

    OpenAIRE

    Vojkuvka, Lukas

    2009-01-01

    La disertación ha sido organizada de la siguiente manera. En el primer capítulo se presenta el estado del arte, donde se exponen algunos conceptos básicos de las propiedades electroquimicaselectroquímicas del alumino, las fases del crecimiento de los poros y el proceso de auto-ordenación de los mismos. El segundo capítulo de la tesis esta relacionado con la preparación y caracterización morfológica de las muestras de alumina porosa. >En el capítulo 4 se desglosan los resultados obtenidos de l...

  15. Alcohol dehydration: Mechanism of ether formation using an alumina catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Shi, B.; Davis, B.H. [Univ. of Kentucky, Lexington, KY (United States)

    1995-12-01

    Ether formation during the dehydration of secondary alcohols, namely, 2-butanol, 3-pentanol, and 1-cyclopentylethanol, was investigated. Using the proper reaction conditions, the yield of di-2-butyl ether during the dehydration of 2-butanol on alumina can be as high as 40%. That ether is formed by adding an alcohol to the alkene is ruled out by the results from deuterium tracer studies. Results from experiments using S(+)- 2-butanol suggest that the formation of di-2-butyl ether occurs by a S{sub N}2-type mechanism. 33 refs., 5 figs., 3 tabs.

  16. Development of a PDMS-grafted alumina membrane and its evaluation as solvent resistant nanofiltration membrane

    NARCIS (Netherlands)

    Pinheiro de Melo, A.F.; Hoogendoorn, D.; Nijmeijer, A.; Winnubst, A.J.A.

    2014-01-01

    A new solvent resistant nanofiltration (SRNF) membrane is developed by grafting a PDMS polymer into the pores of a 5 nm γ-alumina ceramic membrane. These PDMS-grafted γ-alumina membranes were attained through a two-step synthesis. The linking agent, 3-aminopropyltriethoxysilane (APTES), was first ap

  17. Polyethyleneglycol grafting of γ-alumina membranes for solvent resistant nanofiltration

    NARCIS (Netherlands)

    Tanardi, C.R.; Catana, Romina; Barboiu, Mihai; Ayral, André; Vankelecom, I.F.J.; Nijmeijer, A.; Winnubst, A.J.A.

    2016-01-01

    A method is presented for grafting mesoporous g-alumina (pore size 5 nm), supported on an a-alumina ceramic membrane, with polyethylene glycols (PEG). The grafting performance of g-Al2O3 powders with various PEG grafting agents, having different molecular weights, alkoxy groups, and ureido functiona

  18. Effect of Calcination on the Sintering of Gel-Derived, Zirconia-Toughened Alumina

    NARCIS (Netherlands)

    Exter, den Peter; Winnubst, Louis; Leuwerink, Theo H.P.; Burggraaf, Anthonie J.

    1994-01-01

    The densification behavior of ZrO2 (+ 3 mol% Y2O3)/85 wt% Al2O3 powder compacts, prepared by the hydrolysis of metal chlorides, can be characterized by a transition- and an α-alumina densification stage. The sintering behavior is strongly determined by the densification of the transition alumina agg

  19. Effect of Microstructure of Composite Powders on Microstructure and Properties of Microwave Sintered Alumina Matrix Ceramics

    Institute of Scientific and Technical Information of China (English)

    Hanmin Bian; Yong Yang; You Wang; Wei Tian; Haifu Jiang; Zhijuan Hu; Weimin Yu

    2013-01-01

    Two kinds of different structured alumina-titania composite powders were used to prepare alumina matrix ceramics by microwave sintering.One was powder mixture of alumina and titania at a micron-submicron level,in which fused-and-crushed alumina particles (micrometers) was clad with submicron-sized titania.The other was powder mixture of alumina and titania at nanometer-nanometer level,in which nano-sized alumina and nano-sized titania particles were homogeneously mixed by ball-milling and spray dried to prepare spherical alumina-titania composite powders.The effect of the microstructure of composite powders on microstructure and properties of microwave sintered alumina matrix ceramics were investigated.Nano-sized composite (NC) powder showed enhanced sintering behavior compared with micro-sized composite (MC) powders.The asprepared NC ceramic had much denser,finer and more homogenous microstructure than MC ceramic.The mechanical properties of NC ceramic were significantly higher than that of MC ceramic,e.g.the flexural strength,Vickers hardness and fracture toughness of NC ceramic were 85.3%,130.3% and 25.7% higher than that of MC ceramic,respectively.The improved mechanical properties of NC ceramic compared with that of MC ceramic were attributed to the enhanced densification and the finer and more homogeneous microstruc.ture through the use of the nanostructured composite powders.

  20. Ge Honglin: Expand and Consolidate Chemical Alumina to Create World Top-class Brand

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    On June 9,Chinalco convened discussion meeting on integrated utilization of chemical alumina and red mud.Ge Honglin,Chairman and Secretary of the Party Leadership Group of Chinalco,emphasized:"It is imperative to unswervingly expand and consolidate chemical alumina,create world top-class brand,continually propel red mud integrated utilization,and improve integrated utilization rate of resources."

  1. A Review of Alumina Feeding and Dissolution Factors in Aluminum Reduction Cells

    Science.gov (United States)

    Lavoie, Pascal; Taylor, Mark P.; Metson, James B.

    2016-08-01

    Modern aluminum reduction cells use point feeding technology to replenish alumina as it is consumed by the electrolytic process. The dissolution of alumina has become increasingly difficult to control as the cell sizes and electrolysis intensity have increased. The mass of alumina added per unit time is now much higher than a decade ago, and must take place within a smaller electrolyte mixing volume. In order to replenish the alumina concentration evenly, the alumina needs to be delivered, dispersed, dissolved, and distributed throughout the reduction cell. The dissolution itself follows a 4-step process that can be limited by a multitude of factors. The status of the research on each of these factors is reviewed in the present paper. Although research in laboratory cells has been conducted many times, and the impact of many factors on dissolution has been measured, published observations of alumina feeding on industrial cells are very sparse, especially regarding the dissolution dynamics in the space-time domain and the impact of the feeder hole condition. The present paper therefore presents a qualitative model of the factors governing alumina dissolution in industrial cells and offers the hypothesis that maintenance of the feeder hole condition is central to ensuring alumina dissolution and prevention of sludging.

  2. Crystallography-Induced Correlations in Pore Ordering of Anodic Alumina Films

    NARCIS (Netherlands)

    Roslyakov, Ilya V.; Koshkodaev, Dmitry S.; Eliseev, Andrei A.; Hermida-Merino, Daniel; Petukhov, Andrei V.; Napolskii, Kirill S.

    2016-01-01

    A crystallographic approach to tailoring the morphology and ordering degree of the porous structure of alumina films obtained by anodization of single-crystalline aluminum is discussed. The examination of porous structure of anodic alumina films formed on low-index and vicinal planes of Al single cr

  3. Modification of alumina matrices through chemical etching and electroless deposition of nano-Au array for amperometric sensing

    Directory of Open Access Journals (Sweden)

    Valinčius Gintaras

    2007-01-01

    Full Text Available AbstractSimple nanoporous alumina matrix modification procedure, in which the electrically highly insulating alumina barrier layer at the bottom of the pores is replaced with the conductive layer of the gold beds, was described. This modification makes possible the direct electron exchange between the underlying aluminum support and the redox species encapsulated in the alumina pores, thus, providing the generic platform for the nanoporous alumina sensors (biosensors with the direct amperometric signal readout fabrication.

  4. Synthesis of alumina-α using chemical and activation energy por microwave; Sintese de alumina-α utilizando ativacao quimica e energia por microondas

    Energy Technology Data Exchange (ETDEWEB)

    Cartaxo, J.M.; Galdino, M.N.; Neves, G.A., E-mail: juliana@dema.ufcg.edu.br [Universidade Federal de Campina Grande (DEMA/UFCG), PB (Brazil). Unidade Academica de Engenharia de Materiais; Campos, L.F.A.; Menezes, R.R. [Universidade Federal da Paraiba (UFPB), PB (Brazil). Dept. de Engenharia de Materiais; Kiminami, R.H.G.A. [Universidade Federal de Sao Carlos (UFSC), SP (Brazil)

    2012-07-01

    With the great technological advances of alumina, this study aimed to synthesize the α-alumina and chemical activation using microwave energy from aluminum nitrate precursor. The synthesized powders were characterized by X-ray diffraction, thermal analysis (DTA and TGA) and surface area by BET. The chemical activation process was conducted by varying the concentration of the acid solution and exposure time of the material solution. The results proved the effectiveness of chemical activation by accelerating the synthesis process. The results of thermal analysis can observe the thermal decomposition temperature and the possible nucleation of new phases of alumina. The results of X-ray diffraction showed that the powders have the structure of α-alumina with specific areas ranging from 3 to 15m{sup 2}/g pore diameters between 190 to 485nm. (author)

  5. Microstructure-mechanical behaviour relationship in alumina-calcium exaluminate composites; Relaciones microestructura-comportamiento mecanico en materiales de alumina-hexaluminato calcico

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Herencia, A. J.; Moreno, R.; Baudin, C.

    2001-07-01

    The grain growth behaviour of dense alumina materials has been modified by the addition of calcium hexaluminate particles. Maximum dispersion has been obtained by colloidal processing routes. The influence of sintering temperature (1500-1600 degree centigree) on the size and shape of the alumina grains has been established. The mechanical behaviour of three composite materials with the same composition ({approx}10 vol% CA{sub 6}) and large microstructural differences has been studied in comparison with that of monophasic alumina of the same grain size. The influence of grain size and shape on toughness has been established. R-curve behaviour has been detected during fracture of the material with the alumina grains presenting the largest shape factor. (Author) 18 refs.

  6. {sup 99}Tc transmutation by spallation neutrons produced in a large lead block; Transmutation de {sup 99}Tc par des neutrons de spallation produits dans un grand massif de plomb

    Energy Technology Data Exchange (ETDEWEB)

    Andriamonje, S.; Arnould, H.; Bompas, C.A.; Del Moral, R.; Lacoste, V. [Centre d`Etudes Nucleaires, Bordeaux-1 Univ., 33 Gradignan (France); TARC Collaboration under leadership of C. Rubbia

    1997-06-01

    In the search of hybrid system (the coupling of the particle accelerator to an under-critical reactor) for radioactive waste transmutation the TARC (Transmutation by Adiabatic Resonance Crossing) program has been developed. One of the target of the TARC program is the study of the efficiency of a `Energy Amplifier` system for nuclear waste incineration. Among the radioactive wastes the most interesting is the fission product {sup 99}Tc from nuclear plants heaving a half-live of {approx} 10{sup 5} years. Using a fast rabbit technique and gamma ray spectroscopy, the transmutation rate of {sup 99}Tc by spallation neutrons inside a large lead block was measured. The data from each 9 s rabbit cycle were stocked by means of an acquisition system based on the CERN CASCADE code especially adapted for gamma spectroscopy and able to catch large amounts of coincidence events. The measurements technique is described and the preliminary results are given. Also, in progress are simulations using new technique for production and propagation of neutrons in lead. Due to the plenty of spallation neutrons the capability of burning certain nuclear wastes is already proved

  7. Interactions of L-alanine with alumina as studied by vibrational spectroscopy.

    Science.gov (United States)

    Garcia, Ana R; de Barros, Ricardo Brito; Fidalgo, Alexandra; Ilharco, Laura M

    2007-09-25

    The interactions of L-alanine with gamma- and alpha-alumina have been investigated by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). L-alanine/alumina samples were dried from aqueous suspensions, at 36.5 degrees C, with two amino acid concentrations (0.4 and 0.8 mmol g-1) and at different pH values (1, 6, and 13). The vibrational spectra proved that the nature of L-alanine interactions with both aluminas is the same (hydrogen bonding), although the groups involved depend on the L-alanine form and on alumina surface groups, both controlled by the pH. For samples prepared at pH 1, cationic L-alanine [CH3CH(NH3+)COOH] displaces physisorbed water from alumina, and strong hydrogen bonds are established between the carbonyl groups of alanine, as electron donors, and the surface Al-OH2+ groups of alumina. This occurs at the expense of alanine dimer dissociation and breaking of intramolecular bonds. When samples are prepared at pH 6, the interacting groups are Al-OH2+ and the carboxylate groups of zwitterionic L-alanine [CH3CH(NH3+)COO-]. The affinity of L-alanine toward alumina decreases, as the strong NH3+...-OOC intermolecular hydrogen bonds prevail over the interactions with alumina. Thus, for a load of 0.8 mmol g-1, phase segregation is observed. On alpha-alumina, crystal deposition is even observed for a load of 0.4 mmol g-1. At pH 13, the carboxylate groups of anionic L-alanine [CH3CH(NH2)COO-] are not affected by alumina. Instead, hydrogen bond interactions occur between NH2 and the Al-OH surface groups of the substrate. Complementary N2 adsorption-desorption isotherms showed that adsorption of L-alanine occurs onto the alumina pore network for samples prepared at pH 1 and 13, whereas at pH 6 the amino acid/alumina interactions are not strong enough to promote adsorption. The mesoporous structure and the high specific surface area of gamma-alumina make it a more efficient substrate for adsorption of L-alanine. For each alumina, however, it is

  8. Mechanical performance of alumina reinforced with NbC, TiC and WC

    Directory of Open Access Journals (Sweden)

    Wilson Acchar

    2012-12-01

    Full Text Available The incorporation of refractory hard particles in Al2O3-based composites may inhibit grain growth of the matrix, which could significantly contribute to mechanical performance of the composite. The present study aimed to investigate the potential use of NbC as alumina reinforcing material, as an alternative to other carbides such as TiC and WC. Alumina was mixed with a fixed carbide concentration of 30 wt.(% in a ball mill and uniaxially hot-pressed at 1650 ºC under a load of 30 MPa in an inert atmosphere. X-ray diffraction revealed no oxidation products were present after the sintering process. Microstructure analyses indicate a homogeneous carbide distribution in the alumina matrix. Results obtained in this study show that alumina reinforced with NbC is a composite material with properties comparable to those of alumina reinforced with WC and TiC, thereby making it good reinforcing material.

  9. Investigation of Mechanical Behavior of Alfa and Gamma Nano- Alumina/ Epoxy Composite Made By Vartm

    Directory of Open Access Journals (Sweden)

    P. Ghabezi

    2016-06-01

    Full Text Available In this paper, the mechanical properties (flexural and tensional modulus and strength are investigated by manufacturing Epoxy/Glass Nano-composite samples with different Nano-particle wt% (Nano-Alumina to find optimum conditions. The alpha and Gamma grade of Nano alumina were added to the epoxy system with the weight percentage of 1, 2, 3, 4, 5 and 6. The experimental results show that the maximum flexural stiffness in Alfa and Gamma Nano-alumina composite is related to 6 wt% and 4 wt% samples, respectively. And the highest tensional stiffness in Alfa and Gamma Nano-alumina composite is related to 4 wt% and 5 wt% samples, respectively. Also the highest toughness for Alfa and Gamma Nano-composites is observed for 4 wt% and 3 wt% samples and in the same way Nano-alumina in grade Alfa with 1 wt% and Gamma with 3 wt% have highest failure strain.

  10. Robust Mechanical Properties of Electrically Insulative Alumina Films by Supersonic Aerosol Deposition

    Science.gov (United States)

    Lee, Jong-Gun; Cha, You-Hong; Kim, Do-Yeon; Lee, Jong-Hyuk; Lee, Tae-Kyu; Kim, Woo-Young; Park, Jieun; Lee, Dongyun; James, Scott C.; Al-Deyab, Salem S.; Yoon, Sam S.

    2015-08-01

    Electrically insulating alumina films were fabricated on steel substrates using supersonic aerosol deposition and their hardness and scratchability were measured. Alumina particles (0.4-μm diameter) were supersonically sprayed inside a low-pressure chamber using between 1 and 20 nozzle passes. These alumina particles were annealed between 300 and 800 K to determine the temperature's effect on film crystal size (37-41 nm). Smoother surface morphology and increased electrical resistance of the thin films were observed as their thicknesses grew by increasing the number of passes. Resistances of up to 10,000 MΩ demonstrate robust electrical insulation. Significant hardness was measured (1232 hv or 13.33 GPa), but the alumina films could be peeled off with normal loads of 36 and 47 N for films deposited on stainless steel and SKD11 substrates, respectively. High insulation and hardness confirm that these alumina films would make excellent electrical insulators.

  11. Processing, nano indentation and scratch testing of alumina-coated YTZP

    Energy Technology Data Exchange (ETDEWEB)

    Valle, J.; Anglada, M.; Ferrari, B.; Baudin, C.

    2015-10-01

    In this work, alumina-coated YTZP materials are proposed as means to combine the mechanical reliability of YTZP with the stiffness and hardness of alumina. Additionally, compressive stresses are developed in the alumina coating when cooling from the sintering temperature due to the thermal expansion mismatch between alumina and YTZP. The proposed processing method involves dipping of pre-sintered YTZP specimens in stable alumina suspensions and co-sintering of the dipped specimens. The influence of the processing parameters on the macro and microstructure of the materials has been established. Berkovich indentation has been performed to determine the Young's modulus of the substrates and coatings. The structural integrity of the coatings has been analysed using scratch tests. The Young's modulus. The optimised specimens present high resistance to scratch up to loads of 150 N. (Author)

  12. Cellulose extraction from Zoysia japonica pretreated by alumina-doped MgO in AMIMCl.

    Science.gov (United States)

    Liu, Le; Ju, Meiting; Li, Weizun; Jiang, Yang

    2014-11-26

    In this study, alumina-doped MgO was produced as a solid alkali for lignocellulose pretreatment. Pretreatment with alumina-doped MgO disrupted the lignocellulose structure and significantly reduced the lignin content of the Z. japonica. After pretreatment, Z. japonica showed significant solubility in 1-allyl-3-methylimidazolium chloride (AMIMCl). The similar high solubility of pretreated Z. japonica samples by original alumina-doped MgO and used alumina-doped MgO also proved that alumina-doped MgO had strong stability, which can be recycled and used repeatedly. The regenerated cellulose was similar to microcrystalline cellulose according to FTIR and NMR analyses. Compared to microcrystalline cellulose, only the crystallinity of the regenerated cellulose decreased.

  13. Micromechanics of deformation in porous liquid phase sintered alumina under hertzian contact

    Energy Technology Data Exchange (ETDEWEB)

    DIGIOVANNI,ANTHONY A.; CHAN,HELEN M.; HARMER,MARTIN P.; NIED,HERMAN F.

    2000-05-15

    A series of fine-grained porous alumina samples, with and without a liquid phase, were fabricated in compositions matched closely to commercially available alumina used as a microelectronic substrates. Hertzian indentation on monolithic specimens of the glass-containing samples produced a greater quasi-ductile stress-strain response compared to that observed in the pure alumina. Maximum residual indentation depths, determined from surface profilometry, correlated with the stress-strain results. Moreover, microstructural observations from bonded interface specimens revealed significantly more damage in the form of microcracking and under extreme loading, pore collapse, in the glass-containing specimens. The absence of the typical twin faulting mechanism observed for larger-grained alumina suggests that the damage mechanism for quasi-ductility in these fine-grained porous alumina derived from the pores acting as a stress concentrator and the grain boundary glass phase providing a weak path for short crack propagation.

  14. Bond strength of a resin cement to high-alumina and zirconia-reinforced ceramics : The effect of surface conditioning

    NARCIS (Netherlands)

    Felipe Valandro, Luiz; Ozcan, Mutlu; Bottino, Marco Cicero; Bottino, Marco Antonio; Scotti, Roberto; Della Bona, Alvaro

    2006-01-01

    Purpose: The aim of this study was to evaluate the effect of two surface conditioning methods on the microtensile bond strength of a resin cement to three high-strength core ceramics: high alumina-based (In-Ceram Alumina, Procera AllCeram) and zirconia-reinforced alumina-based (in-Ceram Zirconia) ce

  15. Bond strength of a resin cement to high-alumina and zirconia-reinforced ceramics: The effect of surface conditioning

    NARCIS (Netherlands)

    Valandro, L.F.; Ozcan, M.; Bottino, M.C.; Bottino, M.A.; Scotti, R.; Della Bona, A.

    2006-01-01

    Purpose: The aim of this study was to evaluate the effect of two surface conditioning methods on the microtensile bond strength of a resin cement to three high-strength core ceramics: high alumina-based (In-Ceram Alumina, Procera AllCeram) and zirconia-reinforced alumina-based (in-Ceram Zirconia) ce

  16. Interfaces fracas em compósitos de matriz cerâmica de alumina/alumina

    OpenAIRE

    Hablitzel,M.P.; Garcia,D.E.; Hotza,D.

    2011-01-01

    O uso de cerâmicas estruturais é limitado por sua fratura frágil. Compósitos de matriz cerâmica (CMCs) são materiais que possuem reforços estruturais que atuam aumentando a energia necessária para que o material se frature. O presente artigo apresenta uma alternativa para a produção de CMCs em que matriz e fibras são constituídas de alumina. Os mecanismos responsáveis pelo aumento da tenacidade ocorrem devido a uma interfase porosa entre matriz e fibras.

  17. Morphology-controlled electrochemical sensing amaranth at nanomolar levels using alumina

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yuanyuan [School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Gan, Tian [College of Chemistry and Chemical Engineering, Xinyang Normal University, Xinyang 464000 (China); Wan, Chidan [School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Wu, Kangbing, E-mail: kbwu@hust.edu.cn [School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2013-02-18

    Highlights: ► A facile way to tune morphology and sensing properties of alumina was developed. ► Oxidation activities of amaranth on alumina surface were morphology-dependent. ► Alumina microfibers were more active and greatly increased the signal of amaranth. ► Sensitive, rapid, selective and accurate method was developed for amaranth detection. -- Abstract: Different-shaped aluminas were readily prepared via hydrothermal reaction. It was found that the morphology and the electrochemical sensing properties of alumina were heavily dependent on the reaction time. When extending the reaction time from 6 h to 24 h, the obtained alumina samples changed from amorphous bumps to regular microfibers in diameter of 200 nm, as confirmed by scanning electron microscopy. Transmission electron microscopy observation revealed that longer reaction time was beneficial for the formation of porous and uniform fiber-like structures. Electrochemical tests proved that alumina microfibers were more active for the oxidation of amaranth and exhibited much higher enhancement effect, compared with alumina bumps. On the surface of alumina microfibers, the oxidation peak currents of amaranth increased remarkably. The influences of pH value, amount of alumina microfibers, and accumulation time on the signal enhancement of amaranth were discussed. As a result, a novel electrochemical method was developed for the detection of amaranth. The linear range was from 1 to 150 nM, and the detection limit was 0.75 nM after 1-min accumulation. The analytical application in drink samples was investigated, and the results consisted with the values that obtained by high-performance liquid chromatography.

  18. Synthesis of magnesium aluminate spinel by periclase and alumina chlorination

    Energy Technology Data Exchange (ETDEWEB)

    Orosco, Pablo, E-mail: porosco@unsl.edu.ar [Instituto de Investigaciones en Tecnología Química (INTEQUI), Chacabuco y Pedernera, San Luis (Argentina); Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis Chacabuco y Pedernera, San Luis (Argentina); Barbosa, Lucía [Instituto de Investigaciones en Tecnología Química (INTEQUI), Chacabuco y Pedernera, San Luis (Argentina); Instituto de Ciencias Básicas (ICB), Universidad Nacional de Cuyo Parque General San Martín, Mendoza (Argentina); Ruiz, María del Carmen [Instituto de Investigaciones en Tecnología Química (INTEQUI), Chacabuco y Pedernera, San Luis (Argentina); Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis Chacabuco y Pedernera, San Luis (Argentina)

    2014-11-15

    Highlights: • Use of chlorination for the synthesis of magnesium aluminate spinel. • The reagents used were alumina, periclase and chlorine. • Isothermal and non-isothermal assays were performed in air and Cl{sub 2}–N{sub 2} flows. • The chlorination produced magnesium aluminate spinel at 700 °C. • Selectivity of the chlorination reaction to obtain spinel is very high. - Abstract: A pyrometallurgical route for the synthesis of magnesium aluminate spinel by thermal treatment of a mechanical mixture containing 29 wt% MgO (periclase) and 71 wt% Al{sub 2}O{sub 3} (alumina) in chlorine atmosphere was developed and the results were compared with those obtained by calcining the same mixture of oxides in air atmosphere. Isothermal and non-isothermal assays were performed in an experimental piece of equipment adapted to work in corrosive atmospheres. Both reagents and products were analyzed by differential thermal analysis (DTA), X-ray diffraction (XRD) and X-ray fluorescence (XRF). Thermal treatment in Cl{sub 2} atmosphere of the MgO–Al{sub 2}O{sub 3} mixture produces magnesium aluminate spinel at 700 °C, while in air, magnesium spinel is generated at 930 °C. The synthesis reaction of magnesium aluminate spinel was complete at 800 °C.

  19. Thermochemical Analysis of Molybdenum Thin Films on Porous Alumina.

    Science.gov (United States)

    Lee, Kyoungjin; de Lannoy, Charles-François; Liguori, Simona; Wilcox, Jennifer

    2017-01-12

    Molybdenum (Mo) thin films (thickness thin-film composites were stable below 300 °C but had no reactivity toward gases. Mo thin films showed nitrogen incorporation on the surface as well as in the subsurface at 450 °C, as confirmed by X-ray photoelectron spectroscopy. The reactivity toward nitrogen was diminished in the presence of CO2, although no carbon species were detected either on the surface or in the subsurface. The Mo thin films have a very stable native oxide layer, which may further oxidize to higher oxidation states above 500 °C due to the reaction with the porous anodized alumina substrate. The oxidation of Mo thin films was accelerated in the presence of oxidizing gases. At 600 °C in N2, the Mo thin film on anodized alumina was completely oxidized and may also have been volatilized. The results imply that choosing thermally stable and inactive porous supports and operating in nonoxidizing conditions below 500 °C will likely maintain the stability of the Mo composite. This study provides key information about the chemical and structural stability of a Mo thin film on a porous substrate for future membrane applications and offers further insights into the integrity of thin-film composites when exposed to harsh conditions.

  20. Awareness, Preference, Utilization, and Messaging Research for the Spallation Neutron Source and High Flux Isotope Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, Rebecca [Bryant Research, LLC; Kszos, Lynn A [ORNL

    2011-03-01

    Oak Ridge National Laboratory (ORNL) offers the scientific community unique access to two types of world-class neutron sources at a single site - the Spallation Neutron Source (SNS) and the High Flux Isotope Reactor (HFIR). The 85-MW HFIR provides one of the highest steady-state neutron fluxes of any research reactor in the world, and the SNS is one of the world's most intense pulsed neutron beams. Management of these two resources is the responsibility of the Neutron Sciences Directorate (NScD). NScD commissioned this survey research to develop baseline information regarding awareness of and perceptions about neutron science. Specific areas of investigative interest include the following: (1) awareness levels among those in the scientific community about the two neutron sources that ORNL offers; (2) the level of understanding members of various scientific communities have regarding benefits that neutron scattering techniques offer; and (3) any perceptions that negatively impact utilization of the facilities. NScD leadership identified users of two light sources in North America - the Advanced Photon Source (APS) at Argonne National Laboratory and the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory - as key publics. Given the type of research in which these scientists engage, they would quite likely benefit from including the neutron techniques available at SNS and HFIR among their scientific investigation tools. The objective of the survey of users of APS, NSLS, SNS, and HFIR was to explore awareness of and perceptions regarding SNS and HFIR among those in selected scientific communities. Perceptions of SNS and FHIR will provide a foundation for strategic communication plan development and for developing key educational messages. The survey was conducted in two phases. The first phase included qualitative methods of (1) key stakeholder meetings; (2) online interviews with user administrators of APS and NSLS; and (3) one