Transportation of perishable and refrigerated foods in mylar foil bags and insulated containers: a time-temperature study.

Science.gov (United States)

Li, Yanyan; Schrade, John P; Su, Haiyan; Specchio, John J

2014-08-01

Data are lacking on the temperature changes of food during transport without the use of refrigerated trucks. The purpose of this study was to evaluate the ability of several insulated and noninsulated containers with or without frozen gel packs to keep perishable and refrigerated foods within the temperature safe zone in relationship to duration of transport. The study was designed to duplicate the practices exhibited by customers purchasing perishable food products from a cash-and-carry business. Approximately 40 perishable food items were evaluated. Four types of containers were tested: a mylar foil bag, a commercial insulated bag, a generic insulated bag, and a commercial insulated blanket. Mixed foods were placed into these containers with or without frozen gel packs, transported in unrefrigerated vehicles, and monitored for 4 h for temperature changes. Two environmental temperatures, room temperature of 21.1°C and a stress temperature of 37.8°C, were evaluated. The internal temperature and surface temperature of the food products in these containers increased slowly but remained well below the U.S. Food and Drug Administration Food Code requirements. The various containers were similar in their ability to retain coolness. The presence of frozen gel packs dramatically enhanced the cold-holding capacity of the containers. The temperature of foods increased more rapidly when stressed in a heated environment. The containers tested used with the frozen gel packs can keep the surface and internal temperatures of various perishable foods (starting at 4.4°C or less) within the Food Code recommendation of under 21.1°C for 4 h. Cash-and-carry businesses should strongly encourage their retail customers to utilize these containers with frozen gel packs to safely transport perishable foods.

Monitoring the degradation of partly decomposable plastic foils

Directory of Open Access Journals (Sweden)

Rétháti Gabriella

2014-11-01

Full Text Available We have monitored the behaviour of different polyethylene foils including virgin medium density polyethylene (MDPE, MDPE containing pro-oxydative additives (238, 242 and MDPE with pro-oxydative additives and thermoplastic starch (297 in the soil for a period of one year. A foil based on a blend of polyester and polylactic acid (BASF Ecovio served as degradable control. The experiment was carried out by weekly measurements of conductivity and capacity of the soil, since the setup was analogous to a condenser, of which the insulating layer was the foil itself. The twelve replications allowed monthly sampling; the specimen taken out from the soil each month were tested visually for thickness, mechanical properties, morphological and structural changes, and molecular mass. Based on the obtained capacity values, we found that among the polyethylene foils, the one that contained thermoplastic starch extenuated the most. This foil had the greatest decrease in tensile strength and elongation at break due to the presence of thermoplastic starch. The starch can completely degrade in the soil; thus, the foil had cracks and pores. The polyethylene foils that contained pro-oxydant additives showed smaller external change compared to the virgin foil, since there was no available UV radiation and oxygen for their degradation. The smallest change occurred in the virgin polyethylene foil. Among the five examined samples, the commercially available BASF foil showed the largest extenuation and external change, and it deteriorated the most in the soil.

Artificial heart system thermal insulation component development

International Nuclear Information System (INIS)

Svedberg, R.C.; Buckman, R.W. Jr.

1975-01-01

A concentric cup vacuum multifoil insulation system has been selected by virtue of its size, weight, and thermal performance to insulate the hot radioisotope portion of the thermal converter of an artificial implantable heart system. A factor of 2 improvement in thermal performance, based on the heat loss per number of foil layers (minimum system weight and volume) has been realized over conventional spiral wrapped multifoil vacuum insulation. This improvement is the result of the concentric cup construction to maintain a uniform interfoil spacing and the elimination of corner heat losses. Based on external insulation system dimensions (surface area in contact with host body), heat losses of 0.019 W/ cm 2 at 1140 0 K (1600 0 F) and 0.006 W/cm 2 at 920 0 K (1200 0 F) have been achieved. Factors which influence thermal performance of the nickel foil concentric cup insulation system include the number of cups, configuration and method of application of zirconia (ZrO 2 ) spacer material, system pressure, emittance of the cups, and operating temperature

Investigation of Insulation Materials for Future Radioisotope Power Systems

Science.gov (United States)

Cornell, Peggy A.; Hurwitz, Frances I.; Ellis, David L.; Schmitz, Paul C.

2013-01-01

NASA's Radioisotope Power Systems (RPS) Technology Advancement Project is developing next generation high-temperature insulation materials that directly benefit thermal management and improve performance of RPS for future science missions. Preliminary studies on the use of multilayer insulation (MLI) for Stirling convertors used on the Advanced Stirling Radioisotope Generator (ASRG) have shown the potential benefits of MLI for space vacuum applications in reducing generator size and increasing specific power (W/kg) as compared to the baseline Microtherm HT (Microtherm, Inc.) insulation. Further studies are currently being conducted at NASA Glenn Research Center on candidate MLI foils and aerogel composite spacers. This paper presents the method of testing of foils and spacers and experimental results to date.

Metallic insulation transport and strainer clogging tests

International Nuclear Information System (INIS)

Hyvaerinen, J.; Hongisto, O.

1994-06-01

Experiments to probe the transport and clogging properties of metallic (metal reflective) insulation have been carried out in order to provide data for evaluation of their influence on the emergency core cooling and containment spray systems of the Finnish boiling water reactors in the event of a design basis accident. The specific metallic insulation tested was DARMET, provided by Darchem Engineering Ltd. The inner foils of Darmet are dimped. Available literature on the metallic insulation performance under design basis accident conditions has been reviewed. On the basis of the review a parametric approach has been chosen for the transport and clogging experiments. This approach involves testing a wide size range of various shapes of foil pieces. Five sets of experiments have been carried out. The first three sets investigate transport properties of the foil pieces, starting from sedimentation in stagnant waste pool and proceeding to transport in horizontal and vertically circulating flows. The clogging experiments have been addressed the differential pressures obtained due to accumulation of both pure and metallic and a mixture of metallic and fibrous (mineral wool) depris. (4 refs., 24 figs., 2 tabs.)

Transport and screen blockage characteristics of reflective metallic insulation materials

International Nuclear Information System (INIS)

Brocard, D.N.

1984-01-01

In the event of a LOCA within a nuclear power plant, it is possible for insulation debris to be generated by the break jet. Such debris has the potential for PWR sump screen (or BWR RHR suction inlet) blockage and thus can affect the long-term recirculation capability. In addition to the variables of break jet location and orientation, the types and quantities of debris which could be generated are dependent on the insulation materials employed. This experimental investigation was limited to reflective metallic insulation and components thereof. The study was aimed at determining the flow velocities needed to transport the insulation debris to the sump screens and the resulting modes of screen blockage. The tests revealed that thin metallic foils (0.0025 in. and 0.004 in.) could transport at low flow velocities, 0.2 to 0.5 ft/sec. Thicker foils (0.008 in.) transported at higher velocities, 0.4 to 0.8 ft/sec, and as fabricated half cylinder insulation units required velocities in excess of 1.0 ft/sec for transport. The tests also provided information on screen blockage patterns that showed blockage could occur at the lower portion of the screen as foils readily flipped on the screen when reaching it

Hydrodynamic simulations of light ion beam-matter interactions: ablative acceleration of thin foils

International Nuclear Information System (INIS)

Devore, C.R.; Gardner, J.H.; Boris, J.P.; Mosher, D.

1984-01-01

A one-dimensional model is used to study the hydrodynamic response of thin foils to bombardment by an intense proton beam. The beam targets are single- and multilayer planar foils of gold and polystyrene. The main conclusion is that the efficiency of conversion of incident beam energy to directed kinetic energy of the target is maximized by using a multilayer design. For beam parameters associated with the Gamble II device at the Naval Research Laboratory, the simulations yield payload velocities of over 5 cm/μs and energy conversion efficiencies of over 30%. The implications of these results for inertial confinement fusion research are discussed. (author)

Investigation of Insulation Materials for Future Radioisotope Power Systems (RPS)

Science.gov (United States)

Cornell, Peggy A.; Hurwitz, Frances I.; Ellis, David L.; Schmitz, Paul C.

2013-01-01

NASA's Radioisotope Power System (RPS) Technology Advancement Project is developing next generation high temperature insulation materials that directly benefit thermal management and improve performance of RPS for future science missions. Preliminary studies on the use of multilayer insulation (MLI) for Stirling convertors used on the Advanced Stirling Radioisotope Generator (ASRG) have shown the potential benefits of MLI for space vacuum applications in reducing generator size and increasing specific power (W/kg) as compared to the baseline Microtherm HT (Microtherm, Inc.) insulation. Further studies are currently being conducted at NASA Glenn Research Center (GRC) on candidate MLI foils and aerogel composite spacers. This paper presents the method of testing of foils and spacers and experimental results to date.

Field evaluation of reflective insulation in south east Asia

Science.gov (United States)

Teh, Khar San; Yarbrough, David W.; Lim, Chin Haw; Salleh, Elias

2017-12-01

The objective of this research was to obtain thermal performance data for reflective insulations in a South East Asia environment. Thermal resistance data (RSI, m2 ṡ K/W) for reflective insulations are well established from 1-D steady-state tests, but thermal data for reflective insulation in structures like those found in South East Asia are scarce. Data for reflective insulations in South East Asia will add to the worldwide database for this type of energy-conserving material. RSI were obtained from heat flux and temperature data of three identical structures in the same location. One unit did not have insulation above the ceiling, while the second and third units were insulated with reflective insulation with emittance less than 0.05. RSI for the uninsulated test unit varied from 0.37 to 0.40 m2 ṡ K/W. RSI for a single-sheet reflective insulation (woven foil) varied from 2.15 to 2.26 m2 ṡ K/W, while bubble-foil insulation varied from 2.69 to 3.09 m2 ṡ K/W. The range of RSI values resulted from differences in the spacing between the reflective insulation and the roof. In addition, the reflective insulation below the roof lowered attic temperatures by as much as 9.7° C. Reductions in ceiling heat flux of 80 to 90% relative to the uninsulated structure, due to the reflective insulation, were observed.

Experimental and numerical study of heat transfer across insulation wall of a refrigerated integral panel van

International Nuclear Information System (INIS)

Glouannec, Patrick; Michel, Benoit; Delamarre, Guillaume; Grohens, Yves

2014-01-01

This paper presents an experimental and numerical design study of an insulation wall for refrigerated vans. The thermophysical properties of the insulating multilayer panel, the external environment impact (solar irradiation, temperature, etc.) and durability are taken into account. Different tools are used to characterize the thermal performances of the insulation walls and the thermal properties of the insulation materials are measured. In addition, an experiment at the wall scale is carried out and a 2D FEM model of heat and mass transfer within the wall is formulated. Three configurations are studied with this design approach. Multilayer insulation walls containing reflective multi-foil insulation, aerogel and phase change materials (PCM) are tested. Promising results are obtained with these materials, especially the reduction of peak heat transfer and energy consumption during the daytime period. Furthermore, the major influence of solar irradiation is highlighted as it can increase the peak heat transfer crossing the insulation wall by up to 43%. Nevertheless, we showed that the use of reflective multi-foil insulation and aerogel layers allowed decreasing this impact by 27%. - Highlights: • A design study of an insulation wall for a refrigerated van is carried out. • Experimental and numerical studies of multilayer insulation walls are performed. • The major influence of solar irradiation is highlighted. • New insulation materials (reflective multi-foil, aerogel and PCM) are tested

Ion-beam bombardment induced texture in nickel substrates for coated high-Tc superconductors

International Nuclear Information System (INIS)

Wang, S S; Wu, K; Zhou, Y; Godfrey, A; Meng, J; Liu, M L; Liu, Q; Liu, W; Han, Z

2003-01-01

Biaxially textured metal substrates are often used for making YBa 2 Cu 3 O 7-x coated conductors with high critical current density. Generally, specific rolling and high-temperature annealing procedures are required to obtain the biaxial texture for metal substrates. Here, we report on a new method for developing strongly biaxially textured grain structure in rolled nickel tape by argon ion-beam bombardment. X-ray diffraction (XRD) θ-2θ scans have shown that a (200) diffraction peak intensity of the Ni foil processed by ion-beam structure modification (ISM) is two orders of magnitude greater than that of cold-rolled foil, while the (111) and (220) intensities are very weak. In the ISM processed Ni foils, from the rocking curve, the full width at half maximum (FWHM) value of the (200) peak has been found to be less than 5.9 deg., whilst the in-plane FWHM obtained from a pole figure analysis is just 8 deg. We discuss the possible mechanisms leading to the texture changes during ISM. (rapid communication)

Interaction of slow highly-charged ions with metals and insulators

International Nuclear Information System (INIS)

Yamazaki, Y.

2007-01-01

Interaction of slow highly charged ions with insulator as well as metallic surfaces is discussed. In addition to the usual flat surface targets, studies with thin foils having a multitude of straight holes of ∼100 nm in diameter (micro-capillary foil) are introduced, which provide various unique information on the above surface interaction. In the case of an insulator micro-capillary foil, a so-called guiding effect was observed, where slow highly charged ions can transmit through the capillary tunnel keeping their initial charge state even when the capillary axis is tilted against the incident beam. A similar guiding effect has recently been found for slow highly-charged ions transmitted through a single tapered glass capillary. In both cases, the guiding effects are expected to be governed by a self-organized charging and discharging of the inner-wall of the insulator capillary. One of the prominent features of this guiding effect with the tapered capillary is the formation of a nano-size beam, which can be applied in various fields of science including surface nano-modification/analysis, nano-surgery of living cells, etc

Development and evolution of biaxial texture of rolled nickel tapes by ion beam bombardment for high Tc coated conductors

International Nuclear Information System (INIS)

Wang, S.S.; Wu, K.; Shi, K.; Liu, Q.; Han, Z.

2004-01-01

High quality YBa 2 Cu 3 O 7-x films on metallic substrates with high critical current densities well over 10 6 A/cm 2 can be prepared by the rolling assisted biaxially textured substrates (RABiTS) method. Nickel or its alloys have been used as biaxially textured substrates formed through a specific rolling and high temperature annealing procedures. In this paper, we report a newly developed process for developing biaxial texture in rolled Ni tape by argon ion beam bombardment. It is named the ion-beam structure modification (ISM) process. In the ISM processed Ni foils, X-ray diffraction ω scans showed the full width-half maximum (FWHM) value of the (2 0 0) peak was 5.7 deg. . And the electron back scattering diffraction (EBSP) analysis based on scanning electron microscopy showed good {1 0 0} cubic orientation and the mean grain size was determined as about 25 μm. The texture evolution of rolled Ni foils during ISM process is reported also. For ISM process, local temperature elevation and distribution arises from the ion bombardment, coupled with anisotropic incident ion penetration and propagation as a result of channeling effects in the metal lattice, are expected to play the major roles in the development of grain reorientation in the Ni foil. Due to the simplicity and efficiency of the ISM process, the technique shows a great promise for application in the industrial scale production of long-lengths of superconductor tapes

The inaccuracy of heat transfer characteristics for non-insulated and insulated spherical containers neglecting the influence of heat radiation

International Nuclear Information System (INIS)

Wong, King-Leung; Salazar, Jose Luis Leon; Prasad, Leo; Chen, Wen-Lih

2011-01-01

In this investigation, the differences of heat transfer characteristics for insulated and non-insulated spherical containers between considering and neglecting the influence of heat radiation are studied by the simulations in some practical situations. It is found that the heat radiation effect cannot be ignored in conditions of low ambient convection heat coefficients (such ambient air) and high surface emissivities, especially for the non-insulated and thin insulated cases. In most practical situations when ambient temperature is different from surroundings temperature and the emissivity of insulation surface is different from that of metal wall surface, neglecting heat radiation will result in inaccurate insulation effect and heat transfer errors even with very thick insulation. However, the insulation effect considering heat radiation will only increase a very small amount after some dimensionless insulated thickness (such insulation thickness/radius ≥0.2 in this study), thus such dimensionless insulated thickness can be used as the optimum thickness in practical applications. Meanwhile, wrapping a material with low surface emissivity (such as aluminum foil) around the oxidized metal wall or insulation layer (always with high surface emissivity) can achieve very good insulated effect for the non-insulated or thin insulated containers.

Handleable shapes of thermal insulation material

Energy Technology Data Exchange (ETDEWEB)

Hughes, J. T.

1989-01-17

Handleable and machineable shapes of thermal insulation material are made by compacting finely divided thermal insulation material into the cells of a reinforcing honeycomb insulation material into the cells of a reinforcing honeycomb structure. The finely divided thermal insulation material may be, for example, silica aerogel, pyrogenic silica, carbon black, silica gel, volatilised silica, calcium silicate, vermiculate or perlite, or finely divided metal oxides such as alumina or titania. The finely divided thermal insulation material may include an infra-red opacifier and/or reinforcing fibres. The reinforcing honeycomb structure may be made from, for example, metals such as aluminium foil, inorganic materials such as ceramics, organic materials such as plastics materials, woven fabrics or paper. A rigidiser may be employed. The shapes of thermal insulation material are substantially rigid and may be machines, for example by mechanical or laser cutting devices, or may be formed, for example by rolling, into curved or other shaped materials. 12 figs.

Structural changes IN THE Kh20N45M4B nickel alloys and THE Kh16N15M3B steel due to helium ion bombardment

International Nuclear Information System (INIS)

Kalin, B.A.; Chernikov, U.N.; Chernov, I.I.; Kozhevnikov, O.A.; Shishkin, G.N.; Yakushin, V.L.

1986-01-01

Using transmission electron microscopy, x-ray structural analysis, and the thermal desorption techniques, the authors carried out a detailed study of the structural and phase changes, defect formation, and helium accumulation in the He + -bombarded 16-15 austenitic steels and 20-45 nickel alloys. Microstructure of the bombarded specimens was studied using the methods of transmission electron microscopy of thin foils in the EVM-100, and EM-301G electron microscopes. Results of x-ray studies on the bombarded specimens are presented. The conducted studies show that bombardment of structural materials with light ions can lead to significant structural damages and changes in the chemical and phase composition of the surface layer. The possible mechanisms of the changes in the chemical and phase composition include selective sputtering and radiation-induced accelerated diffusion of elements in the field of internal lateral stresses developing during the He + implantation process

Actinide production in 136Xe bombardments of 249Cf

International Nuclear Information System (INIS)

Gregorich, K.E.

1985-08-01

The production cross sections for the actinide products from 136 Xe bombardments of 249 Cf at energies 1.02, 1.09, and 1.16 times the Coulomb barrier were determined. Fractions of the individual actinide elements were chemically separated from recoil catcher foils. The production cross sections of the actinide products were determined by measuring the radiations emitted from the nuclides within the chemical fractions. The chemical separation techniques used in this work are described in detail, and a description of the data analysis procedure is included. The actinide production cross section distributions from these 136 Xe + 249 Cf bombardments are compared with the production cross section distributions from other heavy ion bombardments of actinide targets, with emphasis on the comparison with the 136 Xe + 248 Cm reaction. A technique for modeling the final actinide cross section distributions has been developed and is presented. In this model, the initial (before deexcitation) cross section distribution with respect to the separation energy of a dinuclear complex and with respect to the Z of the target-like fragment is given by an empirical procedure. It is then assumed that the N/Z equilibration in the dinuclear complex occurs by the transfer of neutrons between the two participants in the dinuclear complex. The neutrons and the excitation energy are statistically distributed between the two fragments using a simple Fermi gas level density formalism. The resulting target-like fragment initial cross section distribution with respect to Z, N, and excitation energy is then allowed to deexcite by emission of neutrons in competition with fission. The result is a final cross section distribution with respect to Z and N for the actinide products. 68 refs., 33 figs., 6 tabs

Cryostat with Foil and MLI

Energy Technology Data Exchange (ETDEWEB)

Hwang, Peter K.F.; Gung, Chen-yu

2005-10-06

Induction cores are used to accelerate heavy ion beam array, which are built around the outer diameter of the cryostat housing the superconducting quadruple array. Compact cryostat is highly desirable to reduce the cost of the induction cores. Recent experiences in fabrication of a cryostat for single beam transport revealed that it is possible to reduce the spacing in the cryostat vacuum jacket by using low-emissivity thermal insulation material instead of conventional MLI. However, it is labor-intensive to install the new type of insulation as compared with using MLI. It is promising to build a cost-effective compact cryostat for quadruple magnet array for heavy ion beam array transport by using low-emissivity material combined with conventional MLI as radiation insulation. A matrix of insulation designs and tests will be performed as the feasibility study and for the selection of the optimal thermal insulation as the Phase I work. The selected mixed insulation will be used to build prototype compact cryostats in the Phase II project, which are aiming for housing quadruple doublet array. In this STTR phase I study, a small cryostat has been designed and built to perform calorimetric characterization of the heat load in a liquid helium vessel insulated with a vacuum layer with a nominal clearance of 3.5 mm. The vacuum clearance resembled that used in the warm-bore beam tube region in a prototype cryostat previously built for the heavy ion beam transport experiment. The vacuum clearance was geometrically restricted with a heater shell with the temperature controlled at near 300 K. Various combinations of radiation and thermal shields were installed in the tight vacuum clearance for heat load measurements. The measured heat loads are reported and compared with previous test result using a compact vacuum layer. Further developments of the thermal insulations used in the present study are discussed. The compact cryostat with foil and MLI insulation may be used in the

Ultra-thin smart acoustic metasurface for low-frequency sound insulation

Science.gov (United States)

Zhang, Hao; Xiao, Yong; Wen, Jihong; Yu, Dianlong; Wen, Xisen

2016-04-01

Insulating low-frequency sound is a conventional challenge due to the high areal mass required by mass law. In this letter, we propose a smart acoustic metasurface consisting of an ultra-thin aluminum foil bonded with piezoelectric resonators. Numerical and experimental results show that the metasurface can break the conventional mass law of sound insulation by 30 dB in the low frequency regime (sound insulation performance is attributed to the infinite effective dynamic mass density produced by the smart resonators. It is also demonstrated that the excellent sound insulation property can be conveniently tuned by simply adjusting the external circuits instead of modifying the structure of the metasurface.

Super-insulation

International Nuclear Information System (INIS)

Gerold, J.

1985-01-01

The invention concerns super-insulation, which also acts as spacing between two pressurized surfaces, where the crossing bars in at least two layers are provided, with interposed foil. The super-insulation is designed so that it can take compression forces and limits thermal radiation and thermal conduction sufficiently, where the total density of heat flow is usually limited to a few watts per m 2 . The solution to the problem is characterized by the fact that the bars per layer are parallel and from layer to layer they are at an angle to each other and the crossover positions of the bars of different layers are at fixed places and so form contact columns. The basic idea is that bars crossing over each other to support compression forces are used so that contact columns are formed, which are compressed to a certain extent by the load. (orig./PW) [de

Barrier effect of AlN film in flexible Cu(In,Ga)Se{sub 2} solar cells on stainless steel foil and solar cell

Energy Technology Data Exchange (ETDEWEB)

Li, Boyan; Li, Jianjun [Institute of Photo-electronic Thin Film Devices and Technology, Key Laboratory of Photo-electronic Thin Film Devices and Technology of Tianjin, Nankai University, Tianjin 300071 (China); Wu, Li [The MOE Key Laboratory of Weak-Light Nonlinear Photonics, School of Physics, Nankai University, Tianjin 300071 (China); Liu, Wei; Sun, Yun [Institute of Photo-electronic Thin Film Devices and Technology, Key Laboratory of Photo-electronic Thin Film Devices and Technology of Tianjin, Nankai University, Tianjin 300071 (China); Zhang, Yi, E-mail: yizhang@nankai.edu.cn [Institute of Photo-electronic Thin Film Devices and Technology, Key Laboratory of Photo-electronic Thin Film Devices and Technology of Tianjin, Nankai University, Tianjin 300071 (China)

2015-04-05

Highlights: • The adhension between AlN film and Mo are verygood. • AlN film can be effectively used as the barrier of flexible CIGS solar cell on SS substrate. • AlN film is suitable as the insulation barrier of flexible CIGS solar cell on SS substrate. - Abstract: The AlN film deposited by DC magnetron sputtering on stainless steel (SS) foils was used as the barrier in flexible Cu(In,Ga)Se{sub 2} (CIGS) solar cells on stainless steel foil and characterized comprehensively by X-ray diffraction (XRD), scanning electron microscopy (SEM), I–V, and QE measurements study. The study of AlN as insulation barrier in the flexible CIGS solar cell showed that the adhesion strength between the SS foil and the deposited AlN film was very strong even after annealing at high temperature at 530 °C. More importantly, a high resistance of over 10 MΩ was remained with the film with thickness of around 200 nm after annealing. This indicates that the AlN film is suitable as an effective insulation barrier in flexible CIGS solar cells based on SS foil. In addition, the XRD and SEM results showed that the AlN film did not influence the crystal structure of the Mo film which was deposited upon the AlN layer and used as the electrical contact in CIGS solar cells. It was found that the AlN film contributed to an improved crystallinity of the Mo contact layer compared to the bare SS foil. The combined results of secondary ion mass spectrometry, I–V and EQE measurements of the corresponding flexible CIGS solar cells confirmed that 1 μm-thick AlN film could be used as an efficient barrier layer in CIGS solar cells on SS foil.

Electrical insulator assembly with oxygen permeation barrier

Science.gov (United States)

Van Der Beck, Roland R.; Bond, James A.

1994-01-01

A high-voltage electrical insulator (21) for electrically insulating a thermoelectric module (17) in a spacecraft from a niobium-1% zirconium alloy wall (11) of a heat exchanger (13) filled with liquid lithium (16) while providing good thermal conductivity between the heat exchanger and the thermoelectric module. The insulator (21) has a single crystal alumina layer (SxAl.sub.2 O.sub.3, sapphire) with a niobium foil layer (32) bonded thereto on the surface of the alumina crystal (26) facing the heat exchanger wall (11), and a molybdenum layer (31) bonded to the niobium layer (32) to act as an oxygen permeation barrier to preclude the oxygen depleting effects of the lithium from causing undesirable niobium-aluminum intermetallic layers near the alumina-niobium interface.

Vacuum insulation - Panel properties and building applications. HiPTI - High Performance Thermal Insulation - IEA/ECBCS Annex 39 - Final report

Energy Technology Data Exchange (ETDEWEB)

Erb, M. (ed.)

2005-12-15

This paper takes a look at the properties of vacuum insulation panels (VIP) that have already been developed some time ago for use in appliances such as refrigerators and deep-freezers. Their insulation performance is a factor of five to ten times better than that of conventional insulation. The paper discusses the use of such panels in buildings to provide thin, highly-insulating constructions for walls, roofs and floors. The motivation for examining the applicability of high performance thermal insulation in buildings is discussed, including solutions where severe space limitations and other technical and aesthetic considerations exist. The use of nano-structured materials and laminated foils is examined and discussed. The questions arising from the use of such panels in buildings is discussed and the open questions and risks involved are examined. Finally, an outlook on the introduction of VIP technology is presented and quality assurance aspects are examined. This work was done within the framework of the Task 39 'High Performance Thermal Insulation' of the 'Energy Conservation in Buildings and Community Systems ECBCS' programme of the International Energy Agency IEA.

Thrust augmentation in tandem flapping foils by foil-wake interaction

Science.gov (United States)

Anderson, Erik; Lauder, George

2006-11-01

Propulsion by pitching and heaving airfoils and hydrofoils has been a focus of much research in the field of biologically inspired propulsion. Organisms that use this sort of propulsion are self-propelled, so it is difficult to use standard experimental metrics such as thrust and drag to characterize performance. We have constructed a flapping foil robot mounted in a flume on air-bearings that allows for the determination of self-propelled speed as a metric of performance. We have used a pair of these robots to examine the impact of an upstream flapping foil on a downstream flapping foil as might apply to tandem fins of a swimming organism or in-line swimming of schooling organisms. Self-propelled speed and a force transducer confirmed significant thrust augmentation for particular foil-to-foil spacings, phase differences, and flapping frequencies. Flow visualization shows the mechanism to be related to the effective angle of attack of the downstream foil due to the structure of the wake of the upstream foil. This confirms recent computational work and the hypotheses by early investigators of fish fluid dynamics.

Effect of spacers on the thermal performance of an annular multi-layer insulation

International Nuclear Information System (INIS)

Haim, Y.; Weiss, Y.; Letan, R.

2014-01-01

The current study presents a model and is experimentally conducted in a system of 40 stainless steel coaxial foils, of nitrogen gas, entrapped between the foils, and of spacers, which are zirconia, spherical, 50 μm in size particles, widely dispersed in the gaps between the foils. The model, experimentally verified, relates to radiation between the foils, unobstructed by particles, to conduction in the nitrogen gas, and to conduction across the particles. The study was, in particular, aimed to measure the effective thermal conductivity of the particles and to assess its effect upon the array. At vacuum of 0.092 Pa, the effective thermal conductivity of the particles was 2.13 × 10 −4  W/m K, while the effective thermal conductivity of the array was 4.74 × 10 −4  W/m K. Thus, the low contribution of the particles conduction at vacuum conditions improves the insulation. It reaches 45% of the heat transfer rate. At atmospheric pressure, the effective thermal conductivity of the array reaches 4.5 × 10 −2  W/m K. There, the spacers contribution is negligible. - Highlights: •The multi-layer insulation of cylinder consists of foils separated by particles. •The particles are widely spaced in gaps. •Particles heat transfer rate is almost half of the total in vacuum. •At higher pressures the particles contribution is negligible. •The predicted thermal performance agrees with experimental results

Scanning electron microscope investigations of nuclear pore filters in polyester foils

International Nuclear Information System (INIS)

Hopfe, J.

1980-01-01

In order to understand and characterize the action of nuclear pore filters it is necessary to know their surface, as well as their bulk, structure. In the present work, investigations of the surface structure (pore size, pore density, pore distribution) and of the pore geometry, especially in the bulk of the filters, are carried out by scanning electron microscopic (SEM) studies. The preparation technique needed is liquid-nitrogen freeze-fracturing followed by a conductive-coating step. Nuclear pore filters studied in this paper were produced by a track etching technique. Laboratory specimens were obtained by bombarding 10 μm thick polyester foils with Xe-ions and a subsequent etching with 20% NaOH. The SEM results are shown and discussed. (author)

Foil changing apparatus

International Nuclear Information System (INIS)

Crist, C.E.; Ives, H.C.; Leifeste, G.T.; Miller, R.B.

1988-01-01

A self-contained foil changer apparatus for replenishing foil material across the path of a high energy particle beam is described comprising: a cylindrical hermetically sealed housing comprising an end plate having an aperture defining a beam passageway therethrough; foil supply means disposed inside the housing for storing a foil web and supporting a portion of the web across the beam passageway to form a plane perpendicular to the beam path; a barrel assembly disposed inside the housing; web control means extending through the housing and operably connected to the foil supply means for selectively advancing the foil web to replenish a portion across the beam passageway; and barrel control means extending through the housing and operably connected to the barrel assembly for selectively moving the barrel to and from the advanced and retracted positions

Secondary electron emission from insulators

International Nuclear Information System (INIS)

Kanaya, K.; Ono, S.; Ishigaki, F.

1978-01-01

The high yield of secondary electron emission from insulators due to electron bombardment may be the result of an increase of the depth of escape. The free-electron scattering theory is applied to the high energy of primary beams, but cannot be applied to the low energy of secondary escaping beams because of the large energy gap of the insulators. The plasmon loss with the valence electron is considered when the secondary electrons escape. Based on the energy retardation power formula of the penetration and energy loss of an electron probe into solid targets, secondary electron emissions from insulators are calculated from the assumptions that the distribution of the secondary electrons due to both incident and back-scattered electrons within the target is isotropic and that it follows the absorption law of the Lenard type. The universal yield-energy curve of the secondary electron emission, which is deduced as a function of three parameters such as ionisation potential, valence electron and the back-scattered coefficient in addition to the free-electron density effect, is found to be in good agreement with the experimental results. (author)

Influence of ion bombardment on structural and electrical properties of SiO2 thin films deposited from O2/HMDSO inductively coupled plasmas under continuous wave and pulsed modes

International Nuclear Information System (INIS)

Bousquet, A.; Goullet, A.; Leteinturier, C.; Granier, A.; Coulon, N.

2008-01-01

Low pressure Plasma Enhanced Chemical Vapour Deposition is commonly used to deposit insulators on temperature sensitive substrates. In these processes, the ion bombardment experienced by films during its growth is known to have benefits but also some disadvantages on material properties. In the present paper, we investigate the influence of this bombardment on the structure and the electrical properties of SiO 2 -like film deposited from oxygen/hexa-methyl-di-siloxane radiofrequency plasma in continuous and pulsed modes. First, we studied the ion kinetics thanks to time-resolved measurements by Langmuir probe. After, we showed the ion bombardment in such plasma controls the OH bond content in deposited films. Finally, we highlight the impressive reduction of fixed charge and interface state densities in films obtained in pulsed mode due to a lower ion bombardment. (authors)

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

International Nuclear Information System (INIS)

Rius, G; Yoshimura, M

2013-01-01

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

Post-foil interaction in foil-induced molecular dissociation

International Nuclear Information System (INIS)

Faibis, A.; Kanter, E.P.; Koenig, W.; Plesser, I.; Vager, Z.

1985-01-01

The authors have investigated the foil-induced dissociation of 175- 250- keV/amu CH + , NH + , and OH + , FH + and NeH + ions by coincident detection of the fragment atoms. The dissociation energies corresponding to in-foil and post-foil interactions were deduced from the measured relative flight times of the fragment pairs to a set of detectors downstream from the target. The authors considered final states consisting of a) a proton and a heavy-ion and, b) a hydrogen atom and a heavy-ion. Surprisingly, in both cases the energy released in the post-target interaction shows a similar linear increase with the charge state of the heavy partner

MULPEX: A compact multi-layered polymer foil collector for micrometeoroids and orbital debris

Science.gov (United States)

Kearsley, A. T.; Graham, G. A.; Burchell, M. J.; Taylor, E. A.; Drolshagen, G.; Chater, R. J.; McPhail, D.

Detailed studies of preserved hypervelocity impact residues on spacecraft multi-layer insulation foils have yielded important information about the flux of small particles from different sources in low-Earth orbit (LEO). We have extended our earlier research on impacts occurring in LEO to design and testing of a compact capture device. MUlti- Layer Polymer EXperiment (MULPEX) is simple, cheap to build, lightweight, of no power demand, easy to deploy, and optimised for the efficient collection of impact residue for analysis on return to Earth. The capture medium is a stack of very thin (8 and 40 μm) polyimide foils, supported on poly-tetrafluoroethylene sheet frames, surrounded by a protective aluminium casing. The uppermost foil has a very thin metallic coating for thermal protection and resistance to atomic oxygen and ultra-violet exposure. The casing provides a simple detachable interface for deployment on the spacecraft, facing into the desired direction for particle collection. On return to the laboratory, the stacked foils are separated for examination in a variable pressure scanning electron microscope, without need for surface coating. Analysis of impact residue is performed using energy dispersive X-ray spectrometers. Our laboratory experiments, utilising buck-shot firings of analogues to micrometeoroids (35-38 μm olivine) and space debris (4 μm alumina and 1 mm stainless steel) in a light gas gun, have shown that impact residue is abundant within the foil layers, and preserves a record of the impacting particle, whether of micrometer or millimetre dimensions. Penetrations of the top foil are easily recognised, and act as a proxy for dimensions of the penetrating particle. Impact may cause disruption and melting, but some residue retains sufficient crystallographic structure to show clear Raman lines, diagnostic of the original mineral.

Process for anodizing aluminum foil

International Nuclear Information System (INIS)

Ball, J.A.; Scott, J.W.

1984-01-01

In an integrated process for the anodization of aluminum foil for electrolytic capacitors including the formation of a hydrous oxide layer on the foil prior to anodization and stabilization of the foil in alkaline borax baths during anodization, the foil is electrochemically anodized in an aqueous solution of boric acid and 2 to 50 ppm phosphate having a pH of 4.0 to 6.0. The anodization is interrupted for stabilization by passing the foil through a bath containing the borax solution having a pH of 8.5 to 9.5 and a temperature above 80 0 C. and then reanodizing the foil. The process is useful in anodizing foil to a voltage of up to 760 V

Tungsten foil laminate for structural divertor applications – Analyses and characterisation of tungsten foil

International Nuclear Information System (INIS)

Reiser, Jens; Rieth, Michael; Dafferner, Bernhard; Hoffmann, Andreas; Yi Xiaoou; Armstrong, David E.J.

2012-01-01

It has been attempted for several years to synthesise a tungsten material with a low brittle-to-ductile transition temperature and a high fracture toughness that can be used for structural parts. It was shown in our previous work that tungsten foil is ductile at room temperature and that this ductility can be transformed to bulk by synthesising a tungsten laminate. In this work we want to focus on tungsten foil and assess the microstructure as well as the mechanical properties of the foil. The assessment of the microstructure of 0.1 mm tungsten foil will be performed using electron microscopy. It will be shown that the grains of the tungsten foil have a dimension of 0.5 μm × 3 μm × 15 μm and a clear texture in (1 0 0) 〈0 1 1〉. This texture becomes even more pronounced by annealing. Three-point-bending tests with tungsten foil, as-received, will define the barriers: ductile at room temperature and brittle in liquid nitrogen (−196 °C). This shows that the ductility is a thermally activated process. Recrystallised tungsten foil (annealed for 1 h/2700 °C) shows ductile material behaviour at 200 °C. The paper closes with a discussion on the reasons of the ductility of 0.1 mm tungsten foil. These might be the ultra fine grained (UFG) microstructure or, in other words, a nano microstructure (see tungsten foil as-received), the high amount of mobile edge dislocations, and/or the foil effect, which means that dislocations can move to the surface and are annihilated (see tungsten foil recrystallised).

Ion bombardment modification of surfaces

International Nuclear Information System (INIS)

Auciello, O.

1984-01-01

An historical overview of the main advances in the understanding of bombardment-induced surface topography is presented. The implantation and sputtering mechanisms which are relevant to ion bombardment modification of surfaces and consequent structural, electronic and compositional changes are described. Descriptions of plasma and ion-beam sputtering-induced film formation, primary ion-beam deposition, dual beam techniques, cluster of molecule ion-beam deposition, and modification of thin film properties by ion bombardment during deposition are presented. A detailed account is given of the analytical and computational modelling of topography from the viewpoint of first erosion theory. Finally, an account of the possible application and/or importance of textured surfaces in technologies and/or experimental techniques not considered in previous chapters is presented. refs.; figs.; tabs

Adhesion of silver films to ion-bombarded alumina

International Nuclear Information System (INIS)

Erck, R.A.; Fenske, G.R.

1990-01-01

This paper reports on silver films deposited on alumina substrates using ion bombardment. Adhesion strength was measured as a function of deposition conditions, sputter-cleaning time, and bombarding ion species, using a pull-type adhesion tester. Argon- and argon/oxygen-ion sputtering produced large increases in adhesion strength, with the greatest increases occurring for oxygen-ion bombardment. Adhesion strength increased monotonically as a function of ion sputtering time. At a given deposition rate, further enhancement of adhesion is seen with concurrent ion bombardment

A comparison of atom and ion induced SSIMS - evidence for a charge induced damage effect in insulator materials

International Nuclear Information System (INIS)

Brown, A.; Berg, J.A. van den; Vickerman, J.C.

1985-01-01

A static secondary ion mass spectrometry (SSIMS) study of two very low conductivity materials, polystyrene and niobium pentoxide, using on the one hand a primary ion beam with electron neutralisation, and on the other, atom bombardment, shows that whilst the initial spectra obtained were quite similar, subsequent damage effects were much greater under ion impact conditions. For an equivalent flux density the half-life of the polystyrene surface structure was four times longer under atom bombardment. Significant reduction of the niobium surface was observed under ion bombardment whereas an equivalent atom flux had little apparent effect on the surface oxidation state. These data suggest that the requirement to dissipate the charge delivered to the sample by the primary ion beam contributes significantly to the damage mechanisms in electrically insulating materials. (author)

On results of tests of thermal insulation structural fragments for in-vessel equipment and pipelines of the VG-400 plant on vibrational and acoustic loads

International Nuclear Information System (INIS)

Ledenko, S.A.; Andreev, V.A.; Mirenkov, A.F.; Zakharov, V.A.; Suvorov, V.E.; Prokimnov, V.V.

1990-01-01

Results of vibrostrength and acoustic fatigue tests of the fragments of thermal insulation for in-vessel equipment and pipelines of the VG-400 reactor are presented. The insulation structure is based on the insulation layer made of steel foil and carbon materials. Weak points in the insulation structure, namely - the welded joints of stiffening ribs - are detected in the course of testing. A conclusion is made on the possibility of vibrational test substitution for the acoustic ones

Extraction magnetically insulated diode studies on Gamble II

International Nuclear Information System (INIS)

Neri, J.M.; Boller, J.R.; Ottinger, P.F.; Stephanakis, S.J.; Greenly, J.

1993-01-01

An extraction Magnetically Insulated Diode (MID) with anode and cathode magnetic field coils has been tested on the NRL Gamble II accelerator. The purpose of the experiments is to develop an annular, intense ion beam source for testing ion beam transport physics related to light ion inertial confinement fusion. Initial experiments have been performed with surface flashover ion sources. The experimental challenge has been to obtain a tuning of the 4 magnetic field coils that results in a minimum turn-on time of the ion source and acceptable coupling to the accelerator. Results from several different geometries of magnetic field will be presented. The principal diode diagnostics are the total diode current, net ion current, and corrected diode voltage. Calculations of the magnetic field strength and geometry are performed with the ATHETA code. An active anode ion source is also under development. The initial portion of the accelerator pulse is diverted with a plasma opening switch (POS) and passed through a thin foil that will become the ion source. The foil is swiftly heated by the current pulse and gas is desorbed or diffused from the foil into the anode-cathode gap. The gas is then broken down by the current pulse, forming a dense plasma source on the anode surface. Two different foils are being used. A thin aluminum foil will work with desorbed gases, and provide a beam that is predominately protons. A hydrogen loaded titanium foil, with a paladium overcoating, will use diffused hydrogen, and produce a high purity proton beam. The net result of the POS and active anode plasma source should be much faster ion turn-on time, and better coupling of the ion source to the accelerator. Preliminary results with the active anode sources will be presented

Design and Operation of a Calorimeter for Advanced Multilayer Insulation Testing

Science.gov (United States)

Chato, David; Johnson, Wesley; Dresar, Neil Van

2016-01-01

A calorimeter has been constructed to accurately measure insulation performance with a nominal 90K cold outer boundary and a 20K inner boundary. Unique features of this design include use of mechanical cryocoolers instead cryogens and measurement of the heat load with a calibrated rod to serve as a conduction path. The calorimeter is operational and has completed its first test series. The initial test series was designed to look for differences in performance between a single layer of aluminum foil and a sheet of double aluminized mylar (DAM). Although it has been speculated that the aluminum foil would perform better, since the mylar coating might not thick enough to stop the transmission of long wave length infrared radiation, our testing showed a higher heat load for the aluminum foil than the DAM. The aluminum foil showed a heat load of 132 mW at an 87 K outer temperature and 152 mW at a 107K outer temperature. Whereas the DAM showed a heat load of 66 mW at an 88 K outer temperature and 81 mW at 108 K.

Coupling of an applied field magnetically insulated ion diode to a high power magnetically insulated transmission line system

International Nuclear Information System (INIS)

Maenchen, J.E.

1983-01-01

The coupling of energy from a high power pulsed accelerator through a long triplate magnetically insulated transmission line (MITL) in vacuum to an annular applied magnetic field insulated extraction ion diode is examined. The narrow power transport window and the wave front erosion of the MITL set stringent impedance history conditions on the diode load. A new ion diode design developed to satisfy these criteria with marginal electron insulation is presented. The LION accelerator is used to provide a positive polarity 1.5 MV, 350 kA, 40 ns FWHM pulse with a 30 kA/ns current rate from a triplate MITL source. A transition converts the triplate into a cylindrical cross section which flares into the ion diode load. Extensive current and voltage measurements performed along this structure and on the extracted ion beam provide conclusive evidence that the self insulation condition of the MITL is maintained in the transition by current loss alone. The ion diode utilizes a radial magnetic field between a grounded cathode annular emission tip and a disk anode. A 50 cm 2 dielectric/metal anode area serves as the ion plasma source subject to direct electron bombardment from the opposing cathode tip under marginal magnetic insulation conditions. The ions extracted cross the radial magnetic field and exit the diode volume as an annular cross section beam of peak current about 100 kA. The diode current gradually converts from the initial electron flow to nearly 100% ion current after 30 ns, coupling 60% of the diode energy into ions

Surface roughening under ion bombardment

International Nuclear Information System (INIS)

Bhatia, C.S.

1982-01-01

Ion bombardment can cause roughening of a surface. Inadequate step coverage and poor adhesion of films on such surfaces are of concern. An extreme case of surface roughening results in cone formation under ion bombardment. The results of the investigation, using scanning electron microscopy, is discussed in terms of the role of (a) embedded particles, (b) impurities and (c) surface migration in cone formation on the target surface. (Auth.)

Modification of thin film properties by ion bombardment during deposition

International Nuclear Information System (INIS)

Harper, J.M.E.; Cuomo, J.J.; Gambino, R.J.; Kaufman, H.R.

1984-01-01

Many thin film deposition techniques involve some form of energetic particle bombardment of the growing film. The degree of bombardment greatly influences the film composition, structure and other properties. While in some techniques the degree of bombardment is secondary to the original process design, in recent years more deposition systems are being designed with the capability for controlled ion bombardment of thin films during deposition. The highest degree of control is obtained with ion beam sources which operate independently of the vapor source providing the thin film material. Other plasma techniques offer varying degrees of control of energetic particle bombardment. Deposition methods involving ion bombardment are described, and the basic processes with which film properties are modified by ion bombardment are summarized. (Auth.)

Study of thin insulating films using secondary ion emission

International Nuclear Information System (INIS)

Hilleret, Noel

1973-01-01

Secondary ion emission from insulating films was investigated using a CASTAING-SLODZIAN ion analyzer. Various different aspects of the problem were studied: charge flow across a silica film; the mobilization of sodium during ion bombardment; consequences of the introduction of oxygen on the emission of secondary ions from some solids; determination of the various characteristics of secondary ion emission from silica, silicon nitride and silicon. An example of measurements made using this type of operation is presented: profiles (concentration as a function of depth) of boron introduced by diffusion or implantation in thin films of silica on silicon or silicon nitride. Such measurements have applications in microelectronics. The same method of operation was extended to other types of insulating film, and in particular, to the metallurgical study of passivation films formed on the surface of stainless steels. (author) [fr

Handbook of Thermal Insulation Applications.

Science.gov (United States)

1983-01-01

Wiuppuoror *tIe beamsWiefag ln~ td ~oair ilmstool beams Plate 18. Metal Building Ceilings - A 18b: Fir* hataird rathge may limit the use of foam Insulation...RFCTANGUI.AR SOL TD A = 2(WxL+LxH+HxW) B V = WxLxH H L TRAPEZOID A 2 (A + B) x H A CONE A -n xRxS+ i xR 2 B V =( /3)x R2 x H TRIANGLE A BxH A- 2 CYLI NDER H 2...FABRICATIIG RECTANGULAR HEATING AND COOLING DUCTWORK. FIBERGLAS DUCT BOARD OWENS-CORNING FIBERGLAS CORP GLASS FIBER RIGID BOARD WITH ALUMINUM 4bD FOIL VAPOR

Research on thermal insulation for hot gas ducts

International Nuclear Information System (INIS)

Broeckerhoff, P.

1984-01-01

The inner surfaces of prestressed reactor vessels and hot gas ducts of Gas Cooled High Temperature Reactors need internal thermal insulation to protect the pressure bearing walls from high temperatures. The design parameters of the insulation depend on the reactor type. In a PNP-plant temperature and pressure of the cooling medium helium are proposed to be 950 deg. C and 40 bars, respectively. The experimental work was started at KFA in 1971 for the HHT-project using three test facilities. At first metallic foil insulation and stuffed fibre insulating systems, the hot gas ducting shrouds of which were made of metal, have been tested. Because of the elevated helium temperature in case of PNP and the resulting lower strength of the metallic parts the interest was directed to rigid ceramic materials for the spacers and the inner shrouds. This led to modified structures designed by the INTERATOM company. Tests were performed at KFA. The main object of the investigations was to study the influence of temperature, pressure and axial pressure gradients on the thermal efficiency of the structures. Moreover, the temperatures within the insulation, at the pressure tube, and at the elements which bear the inner shrouds were measured. Thermal fluxes and effective thermal conductivities in axial and circumferential direction of the pressure tube are given, mainly for the INTERATOM-design with spherical spacers. (author)

Chromic acid anodizing of aluminum foil

Science.gov (United States)

Dursch, H.

1988-01-01

The success of the Space Station graphite/epoxy truss structure depends on its ability to endure long-term exposure to the LEO environment, primarily the effects of atomic oxygen and the temperture cycling resulting from the 94 minute orbit. This report describes the development and evaluation of chromic acid anodized (CAA) aluminum foil as protective coatings for these composite tubes. Included are: development of solar absorptance and thermal emittance properties required of Al foil and development of CAA parameters to achieve these optical properties; developing techniques to CAA 25 ft lengths of Al foil; developing bonding processes for wrapping the Al foil to graphite/epoxy tubes; and atomic oxygen testing of the CAA Al foil. Two specifications were developed and are included in the report: Chromic Acid Anodizing of Aluminum Foil Process Specification and Bonding of Anodized Aluminum Foil to Graphite/Epoxy Tubes. Results show that CAA Al foil provides and excellent protective and thermal control coating for the Space Station truss structure.

Tungsten foil laminate for structural divertor applications - Joining of tungsten foils

Science.gov (United States)

Reiser, Jens; Rieth, Michael; Möslang, Anton; Dafferner, Bernhard; Hoffmann, Jan; Mrotzek, Tobias; Hoffmann, Andreas; Armstrong, D. E. J.; Yi, Xiaoou

2013-05-01

This paper is the fourth in our series on tungsten laminates. The aim of this paper is to discuss laminate synthesis, meaning the joining of tungsten foils. It is obvious that the properties of the tungsten laminate strongly depend on the combination of (i) interlayer and (ii) joining technology, as this combination defines (i) the condition of the tungsten foil after joining (as-received or recrystallised) as well as (ii) the characteristics of the interface between the tungsten foil and the interlayer (wettability or diffusion leading to a solid solution or the formation of intermetallics). From the example of tungsten laminates joined by brazing with (i) an eutectic silver copper brazing filler, (ii) copper, (iii) titanium, and (iv) zirconium, the microstructure will be discussed, with special focus on the interface. Based on our assumptions of the mechanism of the extraordinary ductility of tungsten foil we present three syntheses strategies and make recommendations for the synthesis of high temperature tungsten laminates.

Vacuum insulation panels for building applications: A review and beyond

Energy Technology Data Exchange (ETDEWEB)

Baetens, Ruben [Department of Building Materials and Structures, SINTEF Building and Infrastructure, NO-7465 Trondheim (Norway); Department of Civil and Transport Engineering, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim (Norway); Laboratory of Building Physics, Department of Civil Engineering, Catholic University of Leuven (KUL), BE-3001 Heverlee (Belgium); Jelle, Bjoern Petter [Department of Building Materials and Structures, SINTEF Building and Infrastructure, NO-7465 Trondheim (Norway); Department of Civil and Transport Engineering, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim (Norway); Thue, Jan Vincent [Department of Civil and Transport Engineering, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim (Norway); Tenpierik, Martin J. [Faculty of Architecture, Urbanism and Building Sciences, Delft University of Technology, Julianalaan 134, 2628 BL Delft (Netherlands); Grynning, Steinar; Uvsloekk, Sivert [Department of Building Materials and Structures, SINTEF Building and Infrastructure, NO-7465 Trondheim (Norway); Gustavsen, Arild [Department of Architectural Design, History and Technology, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim (Norway)

2010-02-15

Vacuum insulation panels (VIPs) are regarded as one of the most promising high performance thermal insulation solutions on the market today. Thermal performances three to six times better than still-air are achieved by applying a vacuum to an encapsulated micro-porous material, resulting in a great potential for combining the reduction of energy consumption in buildings with slim constructions. However, thermal bridging due to the panel envelope and degradation of thermal performance through time occurs with current technology. Furthermore, VIPs cannot be cut on site and the panels are fragile towards damaging. These effects have to be taken into account for building applications as they may diminish the overall usability and thermal performance. This paper is as far as the authors know the first comprehensive review on VIPs. Properties, requirements and possibilities of foil encapsulated VIPs for building applications are studied based on available literature, emphasizing thermal bridging and degradation through time. An extension is made towards gas-filled panels and aerogels, showing that other high performance thermal insulation solutions do exist. Combining the technology of these solutions and others may lead to a new leap forward. Feasible paths beyond VIPs are investigated and possibilities such as vacuum insulation materials (VIMs) and nano insulation materials (NIMs) are proposed. (author)

Multi-layered foil capture of micrometeoroids and orbital debris in low Earth orbit

Science.gov (United States)

Kearsley, A.; Graham, G.

Much of our knowledge concerning the sub-millimetre orbital debris population that poses a threat to orbiting satellites has been gleaned from examination of surfaces retrieved and subsequently analysed as part of post-flight investigations. The preservation of the hypervelocity impact-derived remnants located on these surfaces is very variable, whether of space debris or micrometeoroid origin. Whilst glass and metallic materials show highly visible impact craters when examined using optical and electron microscopes, complex mixing between the target material and the impacting particle may make unambiguous interpretation of the impactor origin difficult or impossible. Our recent detailed examination of selected multi-layered insulation (MLI) foils from the ISAS Space Flyer Unit (SFU), and our preliminary study of NASA's Trek blanket, exposed on the Mir station, show that these constructions have the potential to preserve abundant residue material of a quality sufficient for detailed analysis. Although there are still limitations on the recognition of certain sources of orbital debris, the foils complement the metal and glass substrates. We suggest that a purpose-built multi-layered foil structure may prove to be extremely effective for rapid collection and unambiguous analysis of impact- derived residues. Such a collector could be used an environmental monitor for ISS, as it would have low mass, high durability, easy deployment, recovery and storage, making it an economically viable and attractive option.

Plasma flow switch characterization for the Los Alamos Foil Implosion Project

International Nuclear Information System (INIS)

Bowers, R.L.; Brownell, J.H.; Greene, A.E.; Peterson, D.L.

1990-01-01

The next system design under consideration for the Los Alamos Foil Implosion Project is projected to deliver tens of mega-amperes of electrical current produced by high-explosive driven flux compression generators on a time scale of about one microsecond to a load foil. The use of such generators, with time scales of order several tenths of a millisecond, leads to considerable pulse shaping problems. Previously it was noted that a commutating switch might serve as an efficient alternative to a closing switch in transferring current from a coaxial transmission line to a cylindrically imploding load. Research at the Air Force Weapons Laboratory (AFWL) has met with considerable success in efficiently transferring currents of order 10 MA to an imploding liner using the plasma flow switch concept (PFS). Besides efficiently transferring current, the plasma flow switch protects the load region from high voltages generated by an opening switch until the current is present to provide magnetic insulation. For these reasons, a PFS is being investigated as the final pulse shaping step in the design. A series of capacitor bank experiments is also being fielded to help investigate physics issues and to benchmark the codes

Effects of crystalline structure in the transmission of ions through thin foils

International Nuclear Information System (INIS)

Archubi, Claudio

2005-01-01

Two fundamental aspects of ion transmission through thin foils are analyzed in this thesis.1) Energy loss.2) Angular distribution.The subject is studied in three different approaches: Theoretically, experimentally and by numerical simulations.In the theoretical approach, the models for the calculation of the energy loss and angular distribution are discussed.They are showed to be unsatisfactory to explain the effects of crystalline structure at low energies.A model is developed to estimate the angular dispersion due to the elastic scattering between the projectile and the target electrons. Simultaneously, angular distribution and energy loss measurements have been performed bombarding polycrystalline and monocrystalline gold and polycrystalline aluminum targets with protons and helium ions with energies in the range of 4-10 keV, together with a detailed study of the foils by electron transmission microscopy techniques.The experimental results are compared with the results of a numerical simulation code, modified and extended in the scope of this thesis.The results show an important influence of crystalline structure and the different targets defects in the angular distribution.This influence is much lower in the case of the angular behaviour of the energy loss (being almost negligible in the case of protons).The most relevant characteristic of the angular behaviour of the energy loss in the case of helium ions is that it is necessary to assume in the simulation method an impact parameter dependence of the stopping coefficient to obtain an agreement between simulation and experimental results [es

Tungsten foil laminate for structural divertor applications – Joining of tungsten foils

Energy Technology Data Exchange (ETDEWEB)

Reiser, Jens, E-mail: jens.reiser@kit.edu [Karlsruhe Institute of Technology (KIT), Institute for Applied Materials (IAM-AWP) (Germany); Rieth, Michael; Möslang, Anton; Dafferner, Bernhard; Hoffmann, Jan [Karlsruhe Institute of Technology (KIT), Institute for Applied Materials (IAM-AWP) (Germany); Mrotzek, Tobias; Hoffmann, Andreas [PLANSEE SE, Reutte (Austria); Armstrong, D.E.J.; Yi, Xiaoou [University of Oxford, Department of Materials (United Kingdom)

2013-05-15

This paper is the fourth in our series on tungsten laminates. The aim of this paper is to discuss laminate synthesis, meaning the joining of tungsten foils. It is obvious that the properties of the tungsten laminate strongly depend on the combination of (i) interlayer and (ii) joining technology, as this combination defines (i) the condition of the tungsten foil after joining (as-received or recrystallised) as well as (ii) the characteristics of the interface between the tungsten foil and the interlayer (wettability or diffusion leading to a solid solution or the formation of intermetallics). From the example of tungsten laminates joined by brazing with (i) an eutectic silver copper brazing filler, (ii) copper, (iii) titanium, and (iv) zirconium, the microstructure will be discussed, with special focus on the interface. Based on our assumptions of the mechanism of the extraordinary ductility of tungsten foil we present three syntheses strategies and make recommendations for the synthesis of high temperature tungsten laminates.

Spallation Neutron Source SNS Diamond Stripper Foil Development

International Nuclear Information System (INIS)

Shaw, Robert W.; Plum, Michael A.; Wilson, Leslie L.; Feigerle, Charles S.; Borden, Michael J.; Irie, Y.; Sugai, I.; Takagi, A.

2007-01-01

Diamond stripping foils are under development for the SNS. Freestanding, flat 300 to 500 (micro)g/cm 2 foils as large as 17 x 25 mm 2 have been prepared. These nano-textured polycrystalline foils are grown by microwave plasma-assisted chemical vapor deposition in a corrugated format to maintain their flatness. They are mechanically supported on a single edge by a residual portion of their silicon growth substrate; fine foil supporting wires are not required for diamond foils. Six foils were mounted on the SNS foil changer in early 2006 and have performed well in commissioning experiments at reduced operating power. A diamond foil was used during a recent experiment where 15 (micro)C of protons, approximately 64% of the design value, were stored in the ring. A few diamond foils have been tested at LANSCE/PSR, where one foil was in service for a period of five months (820 C of integrated injected charge) before it was replaced. Diamond foils have also been tested in Japan at KEK (640 keV H - ) where their lifetimes slightly surpassed those of evaporated carbon foils, but fell short of those for Sugai's new hybrid boron carbon (HBC) foils.

A simple method for the measurement of reflective foil emissivity

International Nuclear Information System (INIS)

Ballico, M. J.; Ham, E. W. M. van der

2013-01-01

Reflective metal foil is widely used to reduce radiative heat transfer within the roof space of buildings. Such foils are typically mass-produced by vapor-deposition of a thin metallic coating onto a variety of substrates, ranging from plastic-coated reinforced paper to 'bubble-wrap'. Although the emissivity of such surfaces is almost negligible in the thermal infrared, typically less than 0.03, an insufficiently thick metal coating, or organic contamination of the surface, can significantly increase this value. To ensure that the quality of the installed insulation is satisfactory, Australian building code AS/NZS 4201.5:1994 requires a practical agreed method for measurement of the emissivity, and the standard ASTM-E408 is implied. Unfortunately this standard is not a 'primary method' and requires the use of specified expensive apparatus and calibrated reference materials. At NMIA we have developed a simple primary technique, based on an apparatus to thermally modulate the sample and record the apparent modulation in infra-red radiance with commercially available radiation thermometers. The method achieves an absolute accuracy in the emissivity of approximately 0.004 (k=2). This paper theoretically analyses the equivalence between the thermal emissivity measured in this manner, the effective thermal emissivity in application, and the apparent emissivity measured in accordance with ASTM-E408

A simple method for the measurement of reflective foil emissivity

Science.gov (United States)

Ballico, M. J.; van der Ham, E. W. M.

2013-09-01

Reflective metal foil is widely used to reduce radiative heat transfer within the roof space of buildings. Such foils are typically mass-produced by vapor-deposition of a thin metallic coating onto a variety of substrates, ranging from plastic-coated reinforced paper to "bubble-wrap". Although the emissivity of such surfaces is almost negligible in the thermal infrared, typically less than 0.03, an insufficiently thick metal coating, or organic contamination of the surface, can significantly increase this value. To ensure that the quality of the installed insulation is satisfactory, Australian building code AS/NZS 4201.5:1994 requires a practical agreed method for measurement of the emissivity, and the standard ASTM-E408 is implied. Unfortunately this standard is not a "primary method" and requires the use of specified expensive apparatus and calibrated reference materials. At NMIA we have developed a simple primary technique, based on an apparatus to thermally modulate the sample and record the apparent modulation in infra-red radiance with commercially available radiation thermometers. The method achieves an absolute accuracy in the emissivity of approximately 0.004 (k=2). This paper theoretically analyses the equivalence between the thermal emissivity measured in this manner, the effective thermal emissivity in application, and the apparent emissivity measured in accordance with ASTM-E408.

Nuclear reactor pressure vessel with an inner metal coating covered with a high temperature resistant thermal insulator

International Nuclear Information System (INIS)

1974-01-01

The thermal insulator covering the metal coating of a reactor vessel is designed for resisting high temperatures. It comprises one or several porous layers of ceramic fibers or of stacked metal foils, covered with a layer of bricks or ceramic tiles. The latter are fixed in position by fasteners comprising pins fixed to the coating and passing through said porous layers and fasteners (nut or bolts) for individually fixing the bricks to said pins, whereas ceramic plugs mounted on said bricks or tiles provide for the thermal insulation of the pins and of the nuts or bolts; such a thermal insulation can be applied to high-temperature reactors or to fast reactors [fr

Design principles for handmade electrical insulation of superconducting joints in W7-X

Energy Technology Data Exchange (ETDEWEB)

Rummel, K., E-mail: kerstin.rummel@ipp.mpg.de [Max Planck Institute for Plasma Physics, EURATOM Association, Wendelsteinstr. 1, 17491 Greifswald (Germany); John, A. [Max Planck Institute for Plasma Physics, EURATOM Association, Wendelsteinstr. 1, 17491 Greifswald (Germany); Sulek, Z. [Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Krakow, Radzikowskiego 152 (Poland)

2013-10-15

Highlights: ► In W-7X there are several types of handmade electrical insulation. ► In general insulation based on impregnated glass tapes and special G10 pieces. ► A proper overlapping of glass tapes turned out to be mandatory. ► Detailed qualification and training helps to minimize the failure rate. ► Visual inspection and Paschen tests after every insulation steps are important. -- Abstract: The superconducting magnet system of the Wendelstein 7-X (W7-X) experiment consists of 50 non-planar and 20 planar coils, 121 bus bars and 14 current leads. The connection between bus bars, coils and current leads will be provided by 198 joints. The joints have to be insulated manually during the assembly of the machine in constraint positions and a tight environment. In general the insulation is based on glass tapes impregnated with epoxy resin and special G10 insulating pieces embedded in the glass tape insulation. In critical areas Kapton{sup ®}-foils are embedded in the insulation. All types of insulation were qualified at mock-ups in a 1:1 model of the expected environment in W7-X. The qualification programme comprises thermal cycling between room temperature and 77 K and high voltage tests under air, under vacuum and under reduced pressure (Paschen test). The paper describes the main principles used for different types of handmade Paschen-tight insulations in W7-X and the visual and electrical tests during and after assembly.

Low-energy foil aberration corrector

International Nuclear Information System (INIS)

Aken, R.H. van; Hagen, C.W.; Barth, J.E.; Kruit, P.

2002-01-01

A spherical and chromatic aberration corrector for electron microscopes is proposed, consisting of a thin foil sandwiched between two apertures. The electrons are retarded at the foil to almost zero energy, so that they can travel ballistically through the foil. It is shown that such a low-voltage corrector has a negative spherical aberration for not too large distances between aperture and foil, as well as a negative chromatic aberration. For various distances the third- and fifth-order spherical aberration coefficients and the first- and second-order chromatic aberration coefficients are calculated using ray tracing. Provided that the foils have sufficient electron transmission the corrector is able to correct the third-order spherical aberration and the first-order chromatic aberration of a typical low-voltage scanning electron microscope. Preliminary results show that the fifth-order spherical aberration and the second-order chromatic aberration can be kept sufficiently low

Microparticle-initiated losses in magnetically insulated transmission lines

International Nuclear Information System (INIS)

Gray, E.W.; Stinnett, R.W.

1986-01-01

The author's discuss the effects of high and hypervelocity microparticles in magnetically-insulated transmission lines (MITLs) and how they may be a possible source for ion production near the anode in early stages of the voltage pulse, and current carriers during and after the power pulse, resulting in power flow losses. Early losses in the voltage pulse, due to microparticles, are estimated to be approximately 0.3 mA/cm/sup 2/. Blistering of the electrode surface, thought to be due to H/sup -/ bombardment, was also observed and appears to be consistent with losses due to negative ions previously reported by one of the authors

Moving foil stripper for a particle accelerator

International Nuclear Information System (INIS)

Gorka, A.J. Jr.

1975-01-01

Thin foils for stripping a particle beam are stored on the edge of a disk spinning in the accelerator vacuum. Cutting a foil at one edge releases the foil to project beyond the disk for insertion into the beam at a time determined by controlling the phase of the disk. A wiper removes a spent foil from the disk. The foil release and wiper are operable from a remote location. (U.S.)

New intensifier foils in roentgenologic diagnostics

Energy Technology Data Exchange (ETDEWEB)

Beyer, H K; Schulze, B

1981-09-01

The main components of the foils are the carrier layer and the luminescent layer, which are in direct contact through an adhesive layer. Carrier layer and adhesive layer absorb and reflect parts of the light. In order to reduce this effect, modern foils are slightly dyed, mostly in the complementary colour of the emitted light. The luminescent layer is attached to the carrier layer by means of a binder. The mean binder content of the luminescent layer is about 10% of the weight of the luminescent material. The particle or crystal range between 5 and 10 ..mu..m. The luminescent layer thickness varies between 0.1 and 0.5 mm, according to the intensification. The imposing with luminescents consequently increases from 20 up to 100 mg/cm/sup 2/. In most cases the luminescent layer is protected by a thin layer (10 to 20 ..mu..m thick) of a very resistant and well-transparent synthetic resin. A foil combination consists of a front and a rear foil, the rear foil often providing a higher degree of intensification than the front foil. Foil quality is mainly defined by the intensification factor, quality on its part is characterized by the modulation transmission function and by the particle structure of the luminescent layer. Quality indicators are also the durability of the foils and the steadiness of the crystal arrangement in the luminescent layer. The representation quality is deteriorated also by the irregular blackening of the roentgen film, resulting from the statistic fluctuations of the roentgen quantums, which are absorbed in the luminescent layer. This unfavourable feature, termed quantum noise, increases with decreasing irradiation intensity, with increasing film gradation, and with increasing sensivity of the film-foil-system. Moreover, an optimal image quality is only possible when film and foil are in good contact conditions (in the cassette).

Computational modeling of plasma-flow switched foil implosions

International Nuclear Information System (INIS)

Lindemuth, I.R.

1985-01-01

A ''plasma-flow'', or ''commutator'', switch has been proposed as a means of achieving high dI/dt in a radially imploding metallic foil plasma. In this concept, an axially moving foil provides the initial coaxial gun discharge path for the prime power source and provides and ''integral'' inductive storage of magnetic energy. As the axially moving foil reaches the end of the coaxial gun, a radially imploding load foil is switched into the circuit. The authors have begun two-dimensional computer modeling of the two-foil implosion system. They use a magnetohydrodynamic (MHD) model which includes tabulated state and transport properties of the metallic foil material. Moving numerical grids are used to achieve adequate resolution of the moving foils. A variety of radiation models are used to compute the radiation generated when the imploding load foil converges on axis. These computations are attempting to examine the interaction of the switching foil with the load foil. In particular, they examine the relationship between foil placement and implosion quality

Lifetimes of carbon foils deposited on etched substrates

International Nuclear Information System (INIS)

Stoner, J.O. Jr.; Bashkin, S.; Hartog, P.D.; Thomas, G.; Yntema, J.L.

1981-01-01

The methods currently in use for producing long-lived carbon foils are listed. The possible common factors which are important in making long lasting foils are a) making a strong, coherent, continuous layer, b) making a foil slack, loose, or baggy, and c) making a foil whose molecular structure minimizes shrinkage. The behavior of foils deposited on etched substrates is compared with foils deposited upon conventional microscope slides

Cleaning of diffusion bonding surface by argon ion bombardment treatment

International Nuclear Information System (INIS)

Wang, Airu; Ohashi, Osamu; Yamaguchi, Norio; Aoki, Masanori; Higashi, Yasuo; Hitomi, Nobuteru

2003-01-01

The specimens of oxygen-free high conductivity copper, SUS304L stainless steel and pure iron were treated by argon ion bombardment and then were bonded by diffusion bonding method. The effects of argon ion bombardment treatment on faying surface morphology, tensile strength of bonding joints and inclusions at the fracture surface were investigated. The results showed that argon ion bombardment treatment was effective to remove the oxide film and contamination at the faying surface and improve the quality of joints. The tensile strength of the bonded joints was improved, and minimum bonding temperature to make the metallic bonding at the interface was lowered by argon ion bombardment treatment. At the joints with argon ion bombardment treatment, ductile fractured surface was seen and the amount of inclusions was obviously decreased

Hyaluronan-lecithin foils and their properties

International Nuclear Information System (INIS)

BiaIopiotrowicz, Tomasz; Janczuk, BronisIaw; Fiedorowicz, Maciej; Khachatryan, Gohar; Tomasik, Piotr; Bakos, Dusan

2006-01-01

Thin, elastic foils of good resistance to the air exposure, patented as wound healing aids, were prepared by evaporation of a blend of lecithin (L) and sodium hyaluronan (H) taken under varying proportions. The contact angle for water, glycerol, formamide, ethylene glycol and diiodomethane, was determined for these foils. The contact angle was correlated against the H:L foil composition. For all liquids but formamide the highest contact angle was noted for the H:L = 2:1 (g g -1 ) ratio. The contact angles provided estimation of the work of adhesion. At the same L:H ratio the work of adhesion was the lowest. It was suggested that lecithin cross-linked hyaluronan. Since the work of adhesion of the studied liquids was similar to that of diiodomethane, it could be concluded that almost all functional groups on the foil surface were completely blocked. Perhaps, at H:L = 2:1 (g g -1 ) a stoichiometric complex of hyaluronic acid with lecithin was formed, and polar functional groups from both reagents were involved. Foils seem to be electrostatic complexes of H with L. Foils with the H:L equal to 2:1 exhibited specific properties confirmed by the IR reflectance spectra of the foils. The thermogravimetry (TG/DTG) also revealed unique thermal behaviour confirming other specific properties of the foil of this composition. For the same ratio a thorough inspection of the scanning electron micrographs (SEM) revealed few irregularly distributed perforations of 1-2 μm in diameter seen as black points, which can be recognized as pores. Properties of the foils determined in the contact angle measurements are nicely backed by the results from thermogravimetric and scanning electron microscopic studies

Foil changer for the Chalk River superconducting cyclotron

International Nuclear Information System (INIS)

Hoffmann, C.R.; Kilborn, R.I.; Mouris, J.E.; Proulx, D.R.; Weaver, J.F.

1985-01-01

Capture of an injected beam in the Chalk River superconducting cyclotron requires that a carbon stripping foil be accurately placed in a dee to intercept the incoming beam. Foil radial position must be precisely adjustable and foils must be easily replaced. A foil changing apparatus has been designed, built and tested to meet these requirements. The main components are a supply magazine, a transport system, and unloading and loading mechanisms. The magazine is on top of the cyclotron. It holds 300 foils and can be isolated from machine vacuum for refilling. Each foil is mounted on a stainless steel frame. A stainless steel roller chain fitted with 33 copper sleeves (shrouds) carries foils, one per shroud, down a dee stem to the midplane. A 12-bit absolute optical shaft encoder senses foil position. To replace a foil a shroud is positioned at the top of the cyclotron, a foil is removed, and another is transferred from the magazine to the empty shroud. Three stepping motors and associated electronics provide mechanical drive and are interfaced with a CAMAC control system

Foil changer for the Chalk River superconducting cyclotron

International Nuclear Information System (INIS)

Hoffmann, C.R.; Kilborn, R.I.; Mouris, J.F.; Proulx, D.R.; Weaver, J.F.

1985-01-01

Capture of an injected beam in the Chalk River superconducting cyclotron requires that a carbon stripping foil be accurately placed in a dee to intercept the incoming beam. Foil radial position must be precisely adjustable and foils must be easily replaced. A foil changing apparatus has been designed, built and tested to meet these requirements. The main components are a supply magazine, a transport system, and unloading and loading mechanisms. The magazine is on top of the loading mechanisms. The magazine is on top of the cyclotron. It holds 300 foils and can be isolated from machine vacuum for refilling. Each foil is mounted on a stainless steel frame. A stainless steel roller chain fitted with 33 copper sleeves (shrouds) carries foils, one per shroud, down a dee stem to the midplane. A 12-bit absolute optical shaft encoder senses foil position. To replace a foil a shroud is positioned at the top of the cyclotron, a foil is removed, and another is transferred from the magazine to the empty shroud. Three stepping motors and associated electronics provide mechanical drive and are interfaced with a CAMAC control system

Experiment and analysis of neutron spectra in a concrete assembly bombarded by 14 MeV neutrons

International Nuclear Information System (INIS)

Oishi, Koji; Tomioka, Kazuyuki; Ikeda, Yujiro; Nakamura, Tomoo.

1988-01-01

Neutron spectrum in concrete bombarded by 14 MeV neutrons was measured using a miniature NE213 spectrometer and multi-foil activation method. A good agreement between those two experimental methods was obtained within experimental errors. The measured spectrum was compared with calculated ones using two-dimensional transport code DOT3.5 with 125 group structure cross section libraries based on ENDF/B-IV, JENDL-2, and JENDL-3T (the testing version of JENDL-3.) In the D-T neutron peak region, measured and calculated neutron spectra agreed well with each other for those libraries. However, disagreements of about -10 % to +50 % and -30 % to +40 % were obtained in the MeV region and still lower neutron energy range, respectively. As a result, it was concluded that those discrepancies were caused by the overestimation of secondary neutrons emitted by inelastic scattering from O, Si, and/or Ca which were the main components of concrete. (author)

Beam-foil study of neon in the EUV with foils of carbon, silver and gold

International Nuclear Information System (INIS)

Demarest, J.A.; Watson, R.L.; Texas A and M Univ., College Station

1988-01-01

A beam-foil study of 40 MeV neon was conducted in the EUV with a 1-meter grazing incidence spectrometer configured with a position sensitive microchannel plate detector. A number of new lines of Ne IX, mainly from transitions to n = 3 levels, were detected in the wavelength region covering 50-350 A. Comparison of the spectra obtained using the different foils revealed that the average charge state of the neon projectiles was nearly one unit higher with carbon than with either of the two metals. Measurements of line intensities versus distance from the foils showed that cascade contributions were greatly reduced for the metals. It was also found that n = 3 states of low l were overpopulated relative to a statistical distribution, irrespective of the foil material. (orig.)

Cylindrical cryogenic calorimeter testing of six types of multilayer insulation systems

Science.gov (United States)

Fesmire, J. E.; Johnson, W. L.

2018-01-01

Extensive cryogenic thermal testing of more than 100 different multilayer insulation (MLI) specimens was performed over the last 20 years for the research and development of evacuated reflective thermal insulation systems. From this data library, 26 MLI systems plus several vacuum-only systems are selected for analysis and comparison. The test apparatus, methods, and results enabled the adoption of two new technical consensus standards under ASTM International. Materials tested include reflectors of aluminum foil or double-aluminized Mylar and spacers of fiberglass paper, polyester netting, silk netting, polyester fabric, or discrete polymer standoffs. The six types of MLI systems tested are listed as follows: Mylar/Paper, Foil/Paper, Mylar/Net, Mylar/Blanket, Mylar/Fabric, Mylar/Discrete. Also tested are vacuum-only systems with different cold surface materials/finishes including stainless steel, black, copper, and aluminum. Testing was performed between the boundary temperatures of 78 K and 293 K (and up to 350 K) using a thermally guarded one-meter-long cylindrical calorimeter (Cryostat-100) for absolute heat flow measurement. Cold vacuum pressures include the full range from 1 × 10-6 torr to 760 torr with nitrogen as the residual gas. System variations include number of layers from one to 80 layers, layer densities from 0.5 to 5 layers per millimeter, and installation techniques such layer-by-layer, blankets (multi-layer assemblies), sub-blankets, seaming, butt-joining, spiral wrapping, and roll-wrapping. Experimental thermal performance data for the different MLI systems are presented in terms of heat flux and effective thermal conductivity. Benchmark cryogenic-vacuum thermal performance curves for MLI are given for comparison with different insulation approaches for storage and transfer equipment, cryostats, launch vehicles, spacecraft, or science instruments.

Optimisation of solar collector foils with transparent thermal insulation. Final report; Optimierung von transparent waermegedaemmten Folien-Speicherkollektoren. Abschlussbericht

Energy Technology Data Exchange (ETDEWEB)

Michaelis, M

1995-02-01

The report describes storage collector foils which are used as hybrid systems. Contents: State of the art - solar test facility - tests on small test collectors - cost reduction. (HW) [Deutsch] Es wird berichtet ueber Folien-Speicherkollektoren, die als Hybridsysteme zum Einsatz kommen. Inhalt der Arbeit: - Stand der Technik - solare Testanlage - Untersuchungen an kleinen Testkollektoreinheiten - Kostenreduzierung. (HW)

Modification of thin film properties by ion bombardment during deposition

International Nuclear Information System (INIS)

Harper, J.M.E.; Cuomo, J.J.; Gambino, R.J.; Kaufman, H.R.

1984-01-01

Deposition methods involving ion bombardment are described, and the basic processes with which film properties are modified by ion bombardment are summarized. Examples of thin film property modification by ion bombardment during deposition, including effects which are primarily compositional as well as those which are primarily structural are presented. The examples demonstrate the usefulness of ion beam techniques in identifying and controlling the fundamental deposition parameters. 68 refs.; 15 figs.; 1 table

Efficient and rapid C. elegans transgenesis by bombardment and hygromycin B selection.

Directory of Open Access Journals (Sweden)

Inja Radman

Full Text Available We report a simple, cost-effective, scalable and efficient method for creating transgenic Caenorhabditis elegans that requires minimal hands-on time. The method combines biolistic bombardment with selection for transgenics that bear a hygromycin B resistance gene on agar plates supplemented with hygromycin B, taking advantage of our observation that hygromycin B is sufficient to kill wild-type C. elegans at very low concentrations. Crucially, the method provides substantial improvements in the success of bombardments for isolating transmitting strains, the isolation of multiple independent strains, and the isolation of integrated strains: 100% of bombardments in a large data set yielded transgenics; 10 or more independent strains were isolated from 84% of bombardments, and up to 28 independent strains were isolated from a single bombardment; 82% of bombardments yielded stably transmitting integrated lines with most yielding multiple integrated lines. We anticipate that the selection will be widely adopted for C. elegans transgenesis via bombardment, and that hygromycin B resistance will be adopted as a marker in other approaches for manipulating, introducing or deleting DNA in C. elegans.

Neutron spectrum determination of d(20)+Be source reaction by the dosimetry foils method

Science.gov (United States)

Stefanik, Milan; Bem, Pavel; Majerle, Mitja; Novak, Jan; Simeckova, Eva

2017-11-01

The cyclotron-based fast neutron generator with the thick beryllium target operated at the NPI Rez Fast Neutron Facility is primarily designed for the fast neutron production in the p+Be source reaction at 35 MeV. Besides the proton beam, the isochronous cyclotron U-120M at the NPI provides the deuterons in the energy range of 10-20 MeV. The experiments for neutron field investigation from the deuteron bombardment of thick beryllium target at 20 MeV were performed just recently. For the neutron spectrum measurement of the d(20)+Be source reaction, the dosimetry foils activation method was utilized. Neutron spectrum reconstruction from resulting reaction rates was performed using the SAND-II unfolding code and neutron cross-sections from the EAF-2010 nuclear data library. Obtained high-flux white neutron field from the d(20)+Be source is useful for the intensive irradiation experiments and cross-section data validation.

Foil fabrication for the ROMANO event. Revision 1

International Nuclear Information System (INIS)

Romo, J.G. Jr.; Weed, J.W.; Griggs, G.E.; Brown, T.G.; Tassano, P.L.

1984-01-01

The Vacuum Processes Lab (VPL), of LLNL's M.E. Dept. - Material Fabrication Division (MFD), conducted various vacuum related support activities for the ROMANO nuclear physics experiment. This report focuses on the foil fabrication activities carried out between July and November 1983 for the ROMANO event. Other vacuum related activities for ROMANO, such as outgassing tests of materials, are covered in separate documentation. VPL was asked to provide 270 coated Parylene foils for the ROMANO event. However, due to the developmental nature of some of the procedures, approximately 400 coated foils were processed. In addition, VPL interacted with MFD's Plastics Shop to help supply Parylene substrates to other organizations (i.e., LBL and commercial vendors) which had also been asked to provide coated foils for ROMANO. The purposes of this report are (A) to document the processes developed and the techniques used to produce the foils, and (B) to suggest future directions. The report is divided into four sections describing: (1) nuclear target foil fabrication, (2) Parylene substrate preparation and production, (3) calibration foil fabrication, and (4) foil and substrate inspections

INJECTION CARBON STRIPPING FOIL ISSUES IN THE SNS ACCUMULATOR RING

International Nuclear Information System (INIS)

BEEBE-WANG, J.; LEE, Y.Y.; RAPARIA, D.; WEI, J.

2001-01-01

We are reporting the results of studies on issues related to the injection stripping foil in the Spallation Neutron Source (SNS) accumulator ring. The problems related to foil heating and foil lifetime, such as current density distribution and temperature distribution in the foil, are investigated. The impact of injection errors on the beam losses at the foil is studied. The particle traversal rate and the beam losses due to scattering in the foil are summarized. Finally, SNS end-to-end simulation results of the foil-missing rate, the foil-hitting rate and the maximum foil temperature are presented

Characterization of beryllium foil produced by hot rolling

International Nuclear Information System (INIS)

Wittenauer, J.; Nieh, T.G.; Waychunas, G.

1992-01-01

Beryllium foil is important for a number of aerospace applications including honeycomb structures and metal-matrix composites. In this study, a method of producing beryllium foil directly from powder or flake is demonstrated. A variety of foils were produced in the thickness range 90-300 μm, free from defects such as pinholes and excessive surface roughness, and exhibiting sufficient formability for honeycomb manufacture. Foil produced directly from powder or flake exhibits crystallographic texture, microstructure, and formability equivalent to foil produced from more massive precursors. (Author)

Catalytic oxidation of silicon by cesium ion bombardment

International Nuclear Information System (INIS)

Souzis, A.E.; Huang, H.; Carr, W.E.; Seidl, M.

1991-01-01

Results for room-temperature oxidation of silicon using cesium ion bombardment and low oxygen exposure are presented. Bombardment with cesium ions is shown to allow oxidation at O 2 pressures orders of magnitude smaller than with noble gas ion bombardment. Oxide layers of up to 30 A in thickness are grown with beam energies ranging from 20--2000 eV, O 2 pressures from 10 -9 to 10 -6 Torr, and total O 2 exposures of 10 0 to 10 4 L. Results are shown to be consistent with models indicating that initial oxidation of silicon is via dissociative chemisorption of O 2 , and that the low work function of the cesium- and oxygen-coated silicon plays the primary role in promoting the oxidation process

Particle velocity measurements in laser irradiated foils using ORVIS

International Nuclear Information System (INIS)

Sheffield, S.A.; Fisk, G.A.

1983-01-01

Aluminum foils from 2- to 200-μm thick have been subjected to a Nd:YAG laser pulse of low irradiance (10 9 W/cm 2 , approx. 10 ns pulse) to produce laser-driven shocks in the foils. The particle velocity history of the foil side opposite the laser deposition was monitored with nanosecond resolution by a velocity interferometer system called ORVIS. These histories indicate a shock reverberation process accelerates the foil. Peak foil velocities can be adequately calculated using a ricket propulsion model developed from experiments at much higher irradiances. A velocity of 1 km/s was developed in a 2-μm-thick free foil in a time of 50 ns. Water-confined foils attained peak particle velocities about three times higher than those of free foils

Collodion-reinforcement and plasma-cleaning of target foils

Science.gov (United States)

Stoner, John O.

2002-03-01

The preparation of evaporated target foils can often be facilitated by use of collodion coatings either on the substrate sides or on the exterior surfaces of the foils. Later, such coatings must usually be removed. Cleaning of a foil is necessary if thin layers of adhesives have crept onto the foil. Removal and/or cleaning can often be done satisfactorily with an oxygen plasma. Apparatus and procedures used for this are described. Foils that were cleaned successfully, and some that were incompatible with the cleaning process are listed.

Collodion-reinforcement and plasma-cleaning of target foils

International Nuclear Information System (INIS)

Stoner, John O.

2002-01-01

The preparation of evaporated target foils can often be facilitated by use of collodion coatings either on the substrate sides or on the exterior surfaces of the foils. Later, such coatings must usually be removed. Cleaning of a foil is necessary if thin layers of adhesives have crept onto the foil. Removal and/or cleaning can often be done satisfactorily with an oxygen plasma. Apparatus and procedures used for this are described. Foils that were cleaned successfully, and some that were incompatible with the cleaning process are listed

Radiation lifetimes and failure mechanisms of carbon stripper foils

International Nuclear Information System (INIS)

Auble, R.L.

1981-01-01

Measurements of lifetimes of thin carbon foils under heavy-ion irradiation are compiled and recent advances in stripper foil technology are reviewed. The impact of recent foil lifetime improvements, many by more than an order of magnitude, on heavy-ion electrostatic accelerators is discussed. Foil inhomogeneities, particularly those caused by sputtering are suggested to be a prime factor in usable foil lifetimes

Fusion welding of thin metal foils

International Nuclear Information System (INIS)

Casey, H.

1975-01-01

Aspects of fusion welding of thin metal foils are reviewed and the current techniques employed at LASL to join foils are described. Techniques for fusion welding approximately 0.025-mm-thick foils of copper, aluminum, and stainless steels have been developed using both electron beam and laser welding equipment. These techniques, together with the related aspects of joint design, tooling and fixturing, joint preparation, and modifications to the commercially available welding equipment, are included in the review. (auth)

Densities of carbon foils

International Nuclear Information System (INIS)

Stoner, J.O. Jr.

1991-01-01

The densities of arc-evaporated carbon target foils have been measured by several methods. The density depends upon the method used to measure it; for the same surface density, values obtained by different measurement techniques may differ by fifty percent or more. The most reliable density measurements are by flotation, yielding a density of 2.01±0.03 g cm -3 , and interferometric step height with the surface density known from auxiliary measurements, yielding a density of 2.61±0.4 g cm -3 . The difference between these density values mayy be due in part to the compressive stresses that carbon films have while still on their substrates, uncertainties in the optical calibration of surface densities of carbon foils, and systematic errors in step-height measurements. Mechanical thickness measurements by micrometer caliper are unreliable due to nonplanarity of these foils. (orig.)

Characterization of U-Mo Foils for AFIP-7

Energy Technology Data Exchange (ETDEWEB)

Edwards, Danny J.; Ermi, Ruby M.; Schemer-Kohrn, Alan L.; Overman, Nicole R.; Henager, Charles H.; Burkes, Douglas; Senor, David J.

2012-11-07

Twelve AFIP in-process foil samples, fabricated by either Y-12 or LANL, were shipped from LANL to PNNL for potential characterization using optical and scanning electron microscopy techniques. Of these twelve, nine different conditions were examined to one degree or another using both techniques. For this report a complete description of the results are provided for one archive foil from each source of material, and one unirradiated piece of a foil of each source that was irradiated in the Advanced Test Reactor. Additional data from two other LANL conditions are summarized in very brief form in an appendix. The characterization revealed that all four characterized conditions contained a cold worked microstructure to different degrees. The Y-12 foils exhibited a higher degree of cold working compared to the LANL foils, as evidenced by the highly elongated and obscure U-Mo grain structure present in each foil. The longitudinal orientations for both of the Y-12 foils possesses a highly laminar appearance with such a distorted grain structure that it was very difficult to even offer a range of grain sizes. The U-Mo grain structure of the LANL foils, by comparison, consisted of a more easily discernible grain structure with a mix of equiaxed and elongated grains. Both materials have an inhomogenous grain structure in that all of the characterized foils possess abnormally coarse grains.

Adhesion of evaporated titanium films to ion-bombarded polyethylene

International Nuclear Information System (INIS)

Bodoe, P.; Sundgren, J.

1986-01-01

Ti films were deposited onto high-density polyethylene (HDPE) samples by electron-beam evaporation. Prior to film deposition the samples were in situ pretreated by Ar ion bombardment using a sputter ion gun. The adhesion of the films, determined as the pull strength required for film failure, was measured as a function of ion dose. HDPE substrates processed at two different temperatures were examined. The adhesion of the Ti films to HDPE samples processed at roughly-equal150 0 C increased with the ion dose to a steady-state value corresponding to the cohesive strength of the HDPE substrate. The adhesion to the samples processed at roughly-equal200 0 C increased to a maximum and then decreased for further ion bombardment to a level of the same order as that for films deposited onto as-prepared samples. The effects of the ion bombardment upon the HDPE surface chemistry were examined by means of x-ray photoelectron spectroscopy (XPS). The ion bombardment resulted in dehydrogenation and cross linking of the surface region and for prolonged ion bombardment, a graphitelike surface was obtained. The film/substrate interface as well as the initial Ti film growth were examined by XPS analysis. A chemical interaction which resulted in Ti--C bonds was observed at the interface. The Ti film growth followed a pronounced three-dimensional growth mode on as-prepared surfaces whereas the ion bombardment resulted in a change toward a more two-dimensional growth mode. The difference in adhesion behavior for the two types of HDPE substrates was found to be due to a difference in the amounts of low molecular weight products present within the substrates

Numerical and experimental investigation of bump foil mechanical behaviour

DEFF Research Database (Denmark)

Larsen, Jon Steffen; Cerda Varela, Alejandro Javier; Santos, Ilmar

2014-01-01

Corrugated foils are utilized in air foil bearings to introduce compliance and damping thus accurate mathematical predictions are important. A corrugated foil behaviour is investigated experimentally as well as theoretically. The experimental investigation is performed by compressing the foil...

FOIL ELEMENT FOR NUCLEAR REACTOR

Science.gov (United States)

Noland, R.A.; Walker, D.E.; Spinrad, B.I.

1963-07-16

A method of making a foil-type fuel element is described. A foil of fuel metal is perforated in; regular design and sheets of cladding metal are placed on both sides. The cladding metal sheets are then spot-welded to each other through the perforations, and the edges sealed. (AEC)

Nuclear target foil fabrication for the Romano Event

International Nuclear Information System (INIS)

Weed, J.W.; Romo, J.G. Jr.; Griggs, G.E.

1984-01-01

The Vacuum Processes Lab, of LLNL's M.E. Dept. - Material Fabrication Division, was requested to provide 250 coated Parylene target foils for a nuclear physics experiment titled the ROMANO Event. Due to the developmental nature of some of the fabrication procedures, approximately 400 coated foils were produced to satisfy the event's needs. The foils were used in the experiment as subkilovolt x-ray, narrow band pass filters, and wide band ultraviolet filters. This paper is divided into three sections describing: (1) nuclear target foil fabrication, (2) Parylene substrate preparation and production, and (3) foil and substrate inspections

Modification of Polymer Materials by Ion Bombardment: Case Studies

International Nuclear Information System (INIS)

Bielinski, D. M.; Jagielski, J.; Lipinski, P.; Pieczynska, D.; Ostaszewska, U.; Piatkowska, A.

2009-01-01

The paper discusses possibility of application of ion beam bombardment for modification of polymers. Changes to composition, structure and morphology of the surface layer produced by the treatment and their influence on engineering and functional properties of wide range of polymer materials are presented. Special attention has been devoted to modification of tribological properties. Ion bombardment results in significant reduction of friction, which can be explained by increase of hardness and wettability of polymer materials. Hard but thin enough skin does not result in cracking but improves their abrasion resistance. Contrary to conventional chemical treatment ion beam bombardment works even for polymers hardly susceptible to modification like silicone rubber or polyolefines.

Technical Development Path for Gas Foil Bearings

Science.gov (United States)

Dellacorte, Christopher

2016-01-01

Foil gas bearings are in widespread commercial use in air cycle machines, turbocompressors and microturbine generators and are emerging in more challenging applications such as turbochargers, auxiliary power units and propulsion gas turbines. Though not well known, foil bearing technology is well over fifty years old. Recent technological developments indicate that their full potential has yet to be realized. This paper investigates the key technological developments that have characterized foil bearing advances. It is expected that a better understanding of foil gas bearing development path will aid in future development and progress towards more advanced applications.

Radioactivity analysis in niobium activation foils

Energy Technology Data Exchange (ETDEWEB)

Mueller, G.E.

1995-06-01

The motivation for this study was to measure and analyze the activity of six (6) niobium (Nb) foils (the x-rays from an internal transition in Nb-93m) and apply this information with previously obtained activation foil data. The niobium data was used to determine the epithermal to MeV range for the neutron spectrum and fluence. The foil activation data was re-evaluated in a spectrum analysis code (STAY`SL) to provide new estimates of the exposure at the Los Alamos Spallation Radiation Effect Facility (LASREF). The activity of the niobium foils was measured and analyzed at the University of Missouri-Columbia (UMC) under the direction of Professor William Miller. The spectrum analysis was performed at the University of Missouri-Rolla (UMR) by Professor Gary Mueller.

Advances in fast-atom-bombardment mass spectroscopy

International Nuclear Information System (INIS)

Hemling, M.E.

1986-01-01

A comparison of fast atom bombardment and field desorption mass spectrometry was made to determine relative sensitivity and applicability. A series of glycosphingolipids and a series of protected oligonucleotides of known structure were analyzed to ascertain the potential utility of fast atom bombardment mass spectrometry in the structural elucidation of novel compounds in these classes. Negative ion mass markers were also developed. Fast atom bombardment was found to be one-to-two orders of magnitude more sensitive than field desorption based on the analysis of a limited number of compounds from several classes. Superior sensitivity was not universal and field desorption was clearly better in certain cases. In the negative ion mode in particular, fast atom bombardment was found to be a useful tool for the determination of the primary structure of glycosphingolipids and oligonucleotides. Carbohydrate sequence and branching information, and a fatty acid and lipid base composition were readily obtained from the mass spectra of glycosphingolipids while bidirectional nucleotide sequence, nucleotide base, and protecting group assignments were obtained for oligonucleotides. Based on this knowledge, a tentative structure of a human peripheral nervous system glycosphingolipid implicated in certain cases of disorders such as amyotrophic lateral sclerosis, Lou Gehrig's Disease, was proposed. Suitable negative ion mass markers were found in dispersions of poly(ethylene) and poly(propylene)glycols in a triethylenetetramine matrix, a matrix which also proved useful in the analysis of glycosphingolipids. These polyglycol dispersions provided ions for calibration to 2300 daltons

Experimental and theoretical studies of bombardment induced surface morphology changes

International Nuclear Information System (INIS)

Carter, G.; Nobes, M.J.; Williams, J.S.

1980-01-01

In this review results of experimental and theoretical studies of solid surface morphology changes due to ion bombardment are discussed. An attempt is undertaken to classify the observed specific features of a structure, generated by ion bombardment [ru

Characterization of laser-cut copper foil X-pinches

Science.gov (United States)

Collins, G. W.; Valenzuela, J. C.; Hansen, S. B.; Wei, M. S.; Reed, C. T.; Forsman, A. C.; Beg, F. N.

2016-10-01

Quantitative data analyses of laser-cut Cu foil X-pinch experiments on the 150 ns quarter-period, ˜250 kA GenASIS driver are presented. Three different foil designs are tested to determine the effects of initial structure on pinch outcome. Foil X-pinch data are also presented alongside the results from wire X-pinches with comparable mass. The X-ray flux and temporal profile of the emission from foil X-pinches differed significantly from that of wire X-pinches, with all emission from the foil X-pinches confined to a ˜3 ns period as opposed to the delayed, long-lasting electron beam emission common in wire X-pinches. Spectroscopic data show K-shell as well as significant L-shell emission from both foil and wire X-pinches. Fits to synthetic spectra using the SCRAM code suggest that pinching foil X's produced a ˜1 keV, ne ≥ 1023 cm-3 plasma. The spectral data combined with the improved reliability of the source timing, flux, and location indicate that foil X-pinches generate a reproducible, K-shell point-projection radiography source that can be easily modified and tailored to suit backlighting needs across a variety of applications.

Direct and Recoil-Induced Electron Emission from Ion-Bombarded Solids

DEFF Research Database (Denmark)

Holmen, G.; Svensson, B.; Schou, Jørgen

1979-01-01

The kinetic emission of secondary electrons from ion-bombarded solid surfaces is split into two contributions, a direct one caused by ionizing collisions between the bombarding ion and target atoms, and an indirect one originating from ionizing collisions undergone by recoil atoms with other target...... atoms. The direct contribution, which has been treated by several authors in previous studies, shows a behavior that is determined primarily by the electronic stopping power of the bombarding ion, while the indirect contribution is nonproportionally related to the nuclear stopping power. This latter...

Destruction of C60 films by boron ion bombardment

International Nuclear Information System (INIS)

Ren Zhongmin; Du Yuancheng; Ying Zhifeng; Xiong Xiaxing; Li Fuming

1995-01-01

C 60 films are bombarded by 100 keV boron ion beams at doses ranging from 3x10 14 to 1x10 16 /cm 2 . The bombarded films are analyzed using Fourier transform infrared spectroscopy (FTIR), Raman spectra and X-ray diffraction (XRD) measurements. Most C 60 soccer-balls in the implanted region in the films are found to be broken at a dose over 1x10 15 /cm 2 , while at a dose less than 6x10 14 /cm 2 a few C 60 molecules remain undestroyed and maintain some crystal structure. The results of the analyses suggest a complete disintegration of a C 60 molecule under B + bombardment. ((orig.))

Carbon stripper foils held in place with carbon fibers

International Nuclear Information System (INIS)

Jolivet, Connie S.; Miller, Shawn A.; Stoner, John O.; Ladd, Peter

2008-01-01

The Spallation Neutron Source (SNS) currently under construction at Oak Ridge National Laboratory, Oak Ridge, Tennessee, is planned to initially utilize carbon stripper foils having areal densities approximately 260 μg/cm 2 . The projected design requires that each foil be supported by only one fixed edge. For stability of the foil, additional support is to be provided by carbon fibers. The feasibility of manufacturing and shipping such mounted carbon foils produced by arc evaporation was studied using two prototypes. Production of the foils is described. Fibers were chosen for satisfactory mechanical strength consistent with minimal interference with the SNS beam. Mounting of the fibers, and packaging of the assemblies for shipping are described. Ten completed assemblies were shipped to SNS for further testing. Preliminary evaluation of the survivability of the foils in the SNS foil changer is described

Microfabricated Segmented-Involute-Foil Regenerator for Stirling Engines

Science.gov (United States)

Ibrahim, Mounir; Danila, Daniel; Simon, Terrence; Mantell, Susan; Sun, Liyong; Gedeon, David; Qiu, Songgang; Wood, Gary; Kelly, Kevin; McLean, Jeffrey

2010-01-01

An involute-foil regenerator was designed, microfabricated, and tested in an oscillating-flow test rig. The concept consists of stacked involute-foil nickel disks (see figure) microfabricated via a lithographic process. Test results yielded a performance of about twice that of the 90-percent random-fiber currently used in small Stirling converters. The segmented nature of the involute- foil in both the axial and radial directions increases the strength of the structure relative to wrapped foils. In addition, relative to random-fiber regenerators, the involute-foil has a reduced pressure drop, and is expected to be less susceptible to the release of metal fragments into the working space, thus increasing reliability. The prototype nickel involute-foil regenerator was adequate for testing in an engine with a 650 C hot-end temperature. This is lower than that required by larger engines, and high-temperature alloys are not suited for the lithographic microfabrication approach.

Properties of polymer foils used as solid-state track detectors

International Nuclear Information System (INIS)

Spurny, F.

1973-05-01

Polymer foils were studied with a view to their application as solid-state alpha track detectors. The detection efficiency was determined as was its alpha energy dependence and the quality of the surface and the natural background of the foils were evaluated. The kinetics of etching was studied in three selected type of foils. Characteristic constants for the selected foils and methods of etching were calculated. The possible applications of the foils as track detectors are discussed and the effect is dealt with of the selected foil and of the method of chemical etching on the foil applicability in nuclear sciences, especially in fast neutron dosimetry and in alpha spectrometry. (author)

A Microfabricated Involute-Foil Regenerator for Stirling Engines

Science.gov (United States)

Tew, Roy; Ibrahim, Mounir; Danila, Daniel; Simon, Terrence; Mantell, Susan; Sun, Liyong; Gedeon, David; Kelly, Kevin; McLean, Jeffrey; Qiu, Songgang

2007-01-01

A segmented involute-foil regenerator has been designed, microfabricated and tested in an oscillating-flow rig with excellent results. During the Phase I effort, several approximations of parallel-plate regenerator geometry were chosen as potential candidates for a new microfabrication concept. Potential manufacturers and processes were surveyed. The selected concept consisted of stacked segmented-involute-foil disks (or annular portions of disks), originally to be microfabricated from stainless-steel via the LiGA (lithography, electroplating, and molding) process and EDM. During Phase II, re-planning of the effort led to test plans based on nickel disks, microfabricated via the LiGA process, only. A stack of nickel segmented-involute-foil disks was tested in an oscillating-flow test rig. These test results yielded a performance figure of merit (roughly the ratio of heat transfer to pressure drop) of about twice that of the 90 percent random fiber currently used in small approx.100 W Stirling space-power convertors-in the Reynolds Number range of interest (50 to 100). A Phase III effort is now underway to fabricate and test a segmented-involute-foil regenerator in a Stirling convertor. Though funding limitations prevent optimization of the Stirling engine geometry for use with this regenerator, the Sage computer code will be used to help evaluate the engine test results. Previous Sage Stirling model projections have indicated that a segmented-involute-foil regenerator is capable of improving the performance of an optimized involute-foil engine by 6 to 9 percent; it is also anticipated that such involute-foil geometries will be more reliable and easier to manufacture with tight-tolerance characteristics, than random-fiber or wire-screen regenerators. Beyond the near-term Phase III regenerator fabrication and engine testing, other goals are (1) fabrication from a material suitable for high temperature Stirling operation (up to 850 C for current engines; up to 1200 C

Very low-energy and low-fluence ion beam bombardment of naked plasmid DNA

International Nuclear Information System (INIS)

Norarat, R.; Semsang, N.; Anuntalabhochai, S.; Yu, L.D.

2009-01-01

Ion beam bombardment of biological organisms has been recently applied to mutation breeding of both agricultural and horticultural plants. In order to explore relevant mechanisms, this study employed low-energy ion beams to bombard naked plasmid DNA. The study aimed at simulation of the final stage of the process of the ion beam bombardment of real cells to check whether and how very low-energy and low-fluence of ions can induce mutation. Argon and nitrogen ions at 5 keV and 2.5 keV respectively bombarded naked plasmid DNA pGFP to very low-fluences, an order of 10 13 ions/cm 2 . Subsequently, DNA states were analyzed using electrophoresis. Results provided evidences that the very low-energy and low-fluence ion bombardment indeed altered the DNA structure from supercoil to short linear fragments through multiple double strand breaks and thus induced mutation, which was confirmed by transfer of the bombarded DNA into bacteria Escherichia coli and subsequent expression of the marker gene.

Ultra-low-energy (<10 eV/u) ion beam bombardment effect on naked DNA

Energy Technology Data Exchange (ETDEWEB)

Thopan, P. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongkumkoon, P. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Prakrajang, K. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Faculty of Science, Maejo University, Chiang Mai 50290 (Thailand); Suwannakachorn, D. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, L.D., E-mail: yuld@thep-center.org [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

2014-05-01

Highlights: • Decelerated ultra-low energy ion beam bombarded naked DNA. • DNA form change induced by ion bombardment was investigated. • N-ion bombardment at 32 eV induced DNA single and double strand breaks. • Ar-ion bombardment at a-few-hundreds eV induced DNA single strand break. - Abstract: Since ion energy deposition in the ion-bombarded materials dominantly occurs in the low-energy range, it is very interesting to know effects from ultra-low-energy ion interaction with DNA for understanding ion-beam-induced genetic mutation. Tens-keV Ar- and N-ion beams were decelerated to ultra-low energy ranging from 20 to 100 eV, or only a few to 10 eV/u, to bombard naked plasmid DNA. The bombarded DNA was analyzed using gel electrophoresis for DNA form changes. The original DNA supercoiled form was found to change to relaxed and linear forms, indicating single or double strand breaks after bombarded by tens-eV ion beam. N-ion beam was found more effective in inducing DNA change and mutation than Ar-ion beam. The study demonstrated that the ion bombardment with energy as low as several-tens eV was able to break DNA strands and thus potentially to cause genetic modification of biological cells. The experimental results were discussed in terms of direct atomic collision between the ions and DNA atoms.

Ultra-low-energy (<10 eV/u) ion beam bombardment effect on naked DNA

International Nuclear Information System (INIS)

Thopan, P.; Thongkumkoon, P.; Prakrajang, K.; Suwannakachorn, D.; Yu, L.D.

2014-01-01

Highlights: • Decelerated ultra-low energy ion beam bombarded naked DNA. • DNA form change induced by ion bombardment was investigated. • N-ion bombardment at 32 eV induced DNA single and double strand breaks. • Ar-ion bombardment at a-few-hundreds eV induced DNA single strand break. - Abstract: Since ion energy deposition in the ion-bombarded materials dominantly occurs in the low-energy range, it is very interesting to know effects from ultra-low-energy ion interaction with DNA for understanding ion-beam-induced genetic mutation. Tens-keV Ar- and N-ion beams were decelerated to ultra-low energy ranging from 20 to 100 eV, or only a few to 10 eV/u, to bombard naked plasmid DNA. The bombarded DNA was analyzed using gel electrophoresis for DNA form changes. The original DNA supercoiled form was found to change to relaxed and linear forms, indicating single or double strand breaks after bombarded by tens-eV ion beam. N-ion beam was found more effective in inducing DNA change and mutation than Ar-ion beam. The study demonstrated that the ion bombardment with energy as low as several-tens eV was able to break DNA strands and thus potentially to cause genetic modification of biological cells. The experimental results were discussed in terms of direct atomic collision between the ions and DNA atoms

Experimental charge fractions of hydrogen scattered from insulators at 50-340 keV

CERN Document Server

Ross, Graham G

2002-01-01

Ion bombardment of insulators induces accumulation of electric charges at and under the insulator surfaces. This paper deals with the effect of the accumulated electric charges on the charge fractions of scattered hydrogen. We have measured and compiled charge fractions of hydrogen, in the energy range (for the scattered particles) from 50 to 340 keV, scattered from polystyrene, polymethylmethacrylate, polycarbonate, polyethylene and silicon. In order to establish the effect of the charge accumulation, some samples have been cut from a thick (1 mm) sheet, while some others have been spin coated (approx 250 nm) onto silicon wafers. Experimental measurements have been fitted with the equation f(0)=Aexp(-V sup 2 /V sub i V sub 0), where f(0) is the neutral fraction, V the velocity, V sub i the 'Bohr velocity' for the electron of projectiles, A and V sub 0 the fitting parameters. Comparisons using the least-square fitting procedure have shown that the accumulation of electric charges on the thick polymer samples ...

Plasma etching to enhance the surface insulating stability of alumina for fusion applications

Directory of Open Access Journals (Sweden)

M. Malo

2016-12-01

Full Text Available A significant increase in the surface electrical conductivity of alumina, considered one of the most promising insulating materials for numerous applications in fusion devices, has been observed during ion bombardment in vacuum due to oxygen loss by preferential sputtering. Although this is expected to cause serious limitations to insulating components functionality, recent studies showed it is possible to restore the damaged lattice by oxygen reincorporation during thermal treatments in air. These studies also revealed a correlation between conductivity and ion beam induced luminescence, which is being used to monitor surface electrical conductivity degradation and help qualify the post irradiation recovery. Work now carried out for Wesgo alumina considers oxygen implantation and plasma etching as additional methods to improve recovered layer depth and quality. Both conductivity and luminescence results indicate the potential use of plasma etching not only for damage recovery, but also as a pre-treatment to enhance material stability during irradiation.

Investigation of the thermal resistance of timber attic spaces with reflective foil and bulk insulation, heat flow up

Energy Technology Data Exchange (ETDEWEB)

Belusko, M.; Bruno, F.; Saman, W. [Institute for Sustainable Systems and Technologies, University of South Australia, Mawson Lakes Boulevard, SA 5095 (Australia)

2011-01-15

An experimental investigation was undertaken in which the thermal resistance for the heat flow through a typical timber framed pitched roofing system was measured under outdoor conditions for heat flow up. The measured thermal resistance of low resistance systems such as an uninsulated attic space and a reflective attic space compared well with published data. However, with higher thermal resistance systems containing bulk insulation within the timber frame, the measured result for a typical installation was as low as 50% of the thermal resistance determined considering two dimensional thermal bridging using the parallel path method. This result was attributed to three dimensional heat flow and insulation installation defects, resulting from the design and construction method used. Translating these results to a typical house with a 200 m{sup 2} floor area, the overall thermal resistance of the roof was at least 23% lower than the overall calculated thermal resistance including two dimensional thermal bridging. When a continuous layer of bulk insulation was applied to the roofing system, the measured values were in agreement with calculated resistances representing a more reliable solution. (author)

Ion bombardment modification of surfaces

International Nuclear Information System (INIS)

Auciello, O.

1984-01-01

Ion bombardment-induced modification of surfaces may be considered one of the significant scientific and technological developments of the last two decades. The understanding acquired concerning the underlying mechanisms of several phenomena occurring during ion-surface interactions has led to applications within different modern technologies. These include microelectronics, surface acoustical and optical technologies, solar energy conversion, thin film technology, ion implantation metallurgy, nuclear track technology, thermonuclear fusion, vacuum technology, cold welding technology, biomedicine (implantology). It has become clear that information on many relevant advances, regarding ion bombardment modification of surfaces is dispersed among journals involving fields sometimes not clearly related. This may result, in some cases, in a loss of the type of interdisciplinary exchange of ideas, which has proved to be so fruitful for the advancement of science and technology. This book has been planned in an attempt to collect at least some of today's relevant information about the experimental and theoretical knowledge related to surface modification and its application to technology. (Auth.)

Induction of antioxidant enzyme activity and lipid peroxidation level in ion-beam-bombarded rice seeds

Energy Technology Data Exchange (ETDEWEB)

Semsang, Nuananong, E-mail: nsemsang@gmail.com [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, LiangDeng [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

2013-07-15

Highlights: ► Ion beam bombarded rice seeds in vacuum. ► Studied seed survival from the ion bombardment. ► Determined various antioxidant enzyme activities and lipid peroxidation level. ► Discussed vacuum, ion species and ion energy effects. ► Attributed the changes to free radical formation due to ion bombardment. -- Abstract: Low-energy ion beam bombardment has been used to mutate a wide variety of plant species. To explore the indirect effects of low-energy ion beam on biological damage due to the free radical production in plant cells, the increase in antioxidant enzyme activities and lipid peroxidation level was investigated in ion-bombarded rice seeds. Local rice seeds were bombarded with nitrogen or argon ion beams at energies of 29–60 keV and ion fluences of 1 × 10{sup 16} ions cm{sup −2}. The activities of the antioxidant enzymes; superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), glutathione reductase (GR), glutathione S-transferase (GST) and lipid peroxidation level were assayed in the germinated rice seeds after ion bombardment. The results showed most of the enzyme activities and lipid peroxidation levels in both the argon and nitrogen bombarded samples were higher than those in the natural control. N-ion bombardment could induce higher levels of antioxidant enzyme activities in the rice samples than the Ar-ion bombardment. Additional effects due to the vacuum condition were found to affect activities of some antioxidant enzymes and lipid peroxidation level. This study demonstrates that ion beam bombardment and vacuum condition could induce the antioxidant enzyme activity and lipid peroxidation level which might be due to free radical production in the bombarded rice seeds.

Stripping foils for the PSB H- injection system

CERN Document Server

Aiba, M; Goddard, B; Weterings, W

2009-01-01

Beam physics considerations for the stripping foil of the PSB H- injection system are described, including the arguments for the foil type, thickness, geometry and positioning. The foil performance considerations are described, including expected stripping efficiency, emittance growth, energy straggling, temperature and lifetime. The required movement ranges and tolerances are detailed, together with the assumptions used.

Topography of InP surface bombarded by O2+ ion beam

International Nuclear Information System (INIS)

Sun Zhaoqi

1997-01-01

The topography of InP surface bombarded by O 2 + ion beam was investigated. Rippled topographies were observed for bombarded samples, and the data show that the ripple formation starts from a sputtering depth of about 0.4 μm. The wavelength and the disorder of the ripples both increase as the sputtering depth increases. The wavelength of the ripples appears to be sputtering depth dependent rather than sputtering rate dependent. It is confirmed that the ion-beam-induced surface rippling can be effectively suppressed by sample rotation during bombardment

Ion bombardment and disorder in amorphous silicon

International Nuclear Information System (INIS)

Sidhu, L.S.; Gaspari, F.; Zukotynski, S.

1997-01-01

The effect of ion bombardment during growth on the structural and optical properties of amorphous silicon are presented. Two series of films were deposited under electrically grounded and positively biased substrate conditions. The biased samples displayed lower growth rates and increased hydrogen content relative to grounded counterparts. The film structure was examined using Raman spectroscopy. The transverse optic like phonon band position was used as a parameter to characterize network order. Biased samples displayed an increased order of the amorphous network relative to grounded samples. Furthermore, biased samples exhibited a larger optical gap. These results are correlated and attributed to reduced ion bombardment effects

Capillary self-alignment of mesoscopic foil components for sensor-systems-in-foil

International Nuclear Information System (INIS)

Arutinov, Gari; Smits, Edsger C P; Van Heck, Gert; Van den Brand, Jeroen; Schoo, Herman F M; Mastrangeli, Massimo; Dietzel, Andreas

2012-01-01

This paper reports on the effective use of capillary self-alignment for low-cost and time-efficient assembly of heterogeneous foil components into a smart electronic identification label. Particularly, we demonstrate the accurate (better than 50 µm) alignment of cm-sized functional foil dies. We investigated the role played by the assembly liquid, by the size and the weight of assembling dies and by their initial offsets in the self-alignment performance. It was shown that there is a definite range of initial offsets allowing dies to align with high accuracy and within approximately the same time window, irrespective of their initial offset. (paper)

Anomalous microstructural changes in III-nitrides under ion bombardment

International Nuclear Information System (INIS)

Kucheyev, S.O.; Williams, J.S.; Jagadish, C.

2002-01-01

Full text: Group-III nitrides (GaN, AlGaN, and InGaN) are currently a 'hot topic' in the physics and material research community due to very important technological applications of these materials in (opto)electronics. In the fabrication of III-nitride-based devices, ion bombardment represents a very attractive processing tool. However, ion-beam-produced lattice disorder and its undesirable consequences limit technological applications of ion implantation. Hence, studies of ion-beam-damage processes in Ill-nitrides are not only physically interesting but also technologically important. In this study, wurtzite GaN, AlGaN, and InGaN films exposed to ion bombardment under a wide range of irradiation conditions are studied by a combination of transmission electron microscopy (TEM), environmental scanning electron microscopy (ESEM), energy dispersive x-ray spectrometry (EDS), atomic force microscopy (AFM), cathodoluminescence (CL), and Rutherford backscattering/channeling (RBS/C) spectrometry. Results show that, unlike the situation for mature semiconductors such as Si and GaAs, Ill-nitrides exhibit a range of intriguing behavior involving extreme microstructural changes under ion bombardment. In this presentation, the following aspects are discussed: (i) formation of lattice defects during ion bombardment, (ii) ion-beam-induced phase transformations, (iii) ion-beam-produced stoichiometric imbalance and associated material decomposition, and (iv) an application of charging phenomena during ESEM imaging for studies of electrical isolation in GaN by MeV light ion irradiation. Emphasis is given to the (powerful) application of electron microscopy techniques for the understanding of physical processes occurring in Ill-nitrides under ion bombardment. Copyright (2002) Australian Society for Electron Microscopy Inc

InN: Fermi level stabilization by low-energy ion bombardment

International Nuclear Information System (INIS)

Piper, L.F.J.; Veal, T.D.; McConville, C.F.; Lu, H.; Schaff, W.J.

2006-01-01

The near-surface electronic properties of InN have been investigated with high-resolution electron-energy loss spectroscopy. Low-energy (∝400 eV) nitrogen ion bombardment followed by low temperature annealing (<300 C) was found to dramatically increase the n-type conductivity of InN, close to the surface. This is explained in terms of the formation of amphoteric defects from the ion bombardment and annealing combined with the band structure of InN. Low-energy ion bombardment and annealing is shown to result in a damage-induced, donor-like defect-profile instead of the expected electron accumulation for InN. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Practical and research aspects of beam-foil spectroscopy

International Nuclear Information System (INIS)

Bashkin, S.

1975-01-01

The application of a heavy-ion accelerator to research in beam-foil spectroscopy requires certain capital equipment which is somewhat unorthodox when viewed from the standpoint of conventional, low-energy nuclear physics. It is necessary that people who wish to expand their accelerator work to include beam-foil studies understand the nature and cost of such major apparatus. We will survey the equipment needs, starting with the particle analyzer at the output of the accelerator and including the equipment used in a variety of beam-foil experiments. Electronic and computer devices will not be discussed since they are essentially identical with those employed in nuclear studies. Considerable attention will be given to optical spectrometers and spectographs including simple instruments which might be used by a laboratory just getting started in beam-foil research, or which has limited financial resources. Attention will be given to the production and use of the exciter foils. We will then discuss some typical beam-foil experiments having to do with the excitation, detection, and analysis of spectral lines from electronic levels in multiply-ionized atoms, and also with the measurement of the mean lives of such levels. Finally, we will review some of the special properties of the beam-foil light source as regards the population of the magnetic sub-states of a given level. Recent work on the character of the emitted light will be presented. That work will deal specifically with the origin of the polarization of the light. The relevant experiments involve varying the angle between the plane of the exciter foil and the particle velocity. (author)

Method and apparatus for coating thin foil with a boron coating

Science.gov (United States)

Lacy, Jeffrey L.

2018-01-16

An apparatus and a process is disclosed for applying a boron coating to a thin foil. Preferably, the process is a continuous, in-line process for applying a coating to a thin foil comprising wrapping the foil around a rotating and translating mandrel, cleaning the foil with glow discharge in an etching chamber as the mandrel with the foil moves through the chamber, sputtering the foil with boron carbide in a sputtering chamber as the mandrel moves through the sputtering chamber, and unwinding the foil off the mandrel after it has been coated. The apparatus for applying a coating to a thin foil comprises an elongated mandrel. Foil preferably passes from a reel to the mandrel by passing through a seal near the initial portion of an etching chamber. The mandrel has a translation drive system for moving the mandrel forward and a rotational drive system for rotating mandrel as it moves forward. The etching chamber utilizes glow discharge on a surface of the foil as the mandrel moves through said etching chamber. A sputtering chamber, downstream of the etching chamber, applies a thin layer comprising boron onto the surface of the foil as said mandrel moves through said sputtering chamber. Preferably, the coated foil passes from the mandrel to a second reel by passing through a seal near the terminal portion of the sputtering chamber.

Radiation induced ion currents in vacuum due to residual He and H, and their expected effect on insulating surfaces

International Nuclear Information System (INIS)

Hodgson, E.R.; Morono, A.; Gonzalez de Vicente, S.M.

2006-01-01

Ceramic insulators and windows in ITER will be subjected to bombardment by energetic hydrogen isotopes and helium as a consequence of ionization of the residual gas by gamma radiation and acceleration of the ions by the local electric fields. Most of the energy carried by these particles will be deposited at or very near the surface giving rise to possible electrical and optical degradation. Severe surface electrical degradation has recently been observed when oxide materials are implanted to low doses (10 15 ions/cm 2 ) with protons and alpha particles at temperatures between 50 and 450 o C. In order to estimate the relevance to fusion applications and hence the lifetime of ceramic insulators in ITER it is necessary to quantify possible ion currents generated in the residual gas by measuring radiation induced electrical conductivity for hydrogen isotopes and helium gases at low pressures and then perform experiments in which ceramic candidate materials are subjected to ion bombardment at representative currents and energies. To determine the magnitude of radiation generated ion currents, experiments have been carried out in a special gas chamber mounted in the beam line of a 2 MeV Van de Graaff electron accelerator, with the gases being irradiated through an 0.05 x 10 -3 m thick aluminium window with 1.8 MeV electrons. A guarded volume was defined between two parallel square copper plate electrodes separated by 1.5 x 10 -2 m. The experimental set-up permitted an electric field to be applied to the irradiated volume of gas, and the electric current flowing through the ionized gas to be measured. For these experiments the radiation beam was perpendicular to the electric field direction. In this way radiation induced conductivity for helium and hydrogen has been measured at pressures between about 1000 and 10 -3 mbar (10 -5 to 10 -1 Pa), radiation dose rates of 30 Gy/s and applied voltages up to 1500 volts. The radiation induced electrical currents for low pressure

Induction of antioxidant enzyme activity and lipid peroxidation level in ion-beam-bombarded rice seeds

Science.gov (United States)

Semsang, Nuananong; Yu, LiangDeng

2013-07-01

Low-energy ion beam bombardment has been used to mutate a wide variety of plant species. To explore the indirect effects of low-energy ion beam on biological damage due to the free radical production in plant cells, the increase in antioxidant enzyme activities and lipid peroxidation level was investigated in ion-bombarded rice seeds. Local rice seeds were bombarded with nitrogen or argon ion beams at energies of 29-60 keV and ion fluences of 1 × 1016 ions cm-2. The activities of the antioxidant enzymes; superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), glutathione reductase (GR), glutathione S-transferase (GST) and lipid peroxidation level were assayed in the germinated rice seeds after ion bombardment. The results showed most of the enzyme activities and lipid peroxidation levels in both the argon and nitrogen bombarded samples were higher than those in the natural control. N-ion bombardment could induce higher levels of antioxidant enzyme activities in the rice samples than the Ar-ion bombardment. Additional effects due to the vacuum condition were found to affect activities of some antioxidant enzymes and lipid peroxidation level. This study demonstrates that ion beam bombardment and vacuum condition could induce the antioxidant enzyme activity and lipid peroxidation level which might be due to free radical production in the bombarded rice seeds.

Additional security features for optically variable foils

Science.gov (United States)

Marshall, Allan C.; Russo, Frank

1998-04-01

For thousands of years, man has exploited the attraction and radiance of pure gold to adorn articles of great significance. Today, designers decorate packaging with metallic gold foils to maintain the prestige of luxury items such as perfumes, chocolates, wine and whisky, and to add visible appeal and value to wide range of products. However, today's products do not call for the hand beaten gold leaf of the Ancient Egyptians, instead a rapid production technology exists which makes use of accurately coated thin polymer films and vacuum deposited metallic layers. Stamping Foils Technology is highly versatile since several different layers may be combined into one product, each providing a different function. Not only can a foil bring visual appeal to an article, it can provide physical and chemical resistance properties and also protect an article from human forms of interference, such as counterfeiting, copying or tampering. Stamping foils have proved to be a highly effective vehicle for applying optical devices to items requiring this type of protection. Credit cards, bank notes, personal identification documents and more recently high value packaged items such as software and perfumes are protected by optically variable devices applied using stamping foil technology.

Thermal Performance Testing of Cryogenic Multilayer Insulation with Silk Net Spacers

International Nuclear Information System (INIS)

Johnson, W L; Frank, D J; Nast, T C; Fesmire, J E

2015-01-01

Early comprehensive testing of cryogenic multilayer insulation focused on the use of silk netting as a spacer material. Silk netting was used for multiple test campaigns that were designed to provide baseline thermal performance estimates for cryogenic insulation systems. As more focus was put on larger systems, the cost of silk netting became a deterrent and most aerospace insulation firms were using Dacron (or polyester) netting spacers by the early 1970s. In the midst of the switch away from silk netting there was no attempt to understand the difference between silk and polyester netting, though it was widely believed that the silk netting provided slightly better performance. Without any better reference for thermal performance data, the silk netting performance correlations continued to be used. In order to attempt to quantify the difference between the silk netting and polyester netting, a brief test program was developed. The silk netting material was obtained from Lockheed Martin and was tested on the Cryostat-100 instrument in three different configurations, 20 layers with both single and double netting and 10 layers with single netting only. The data show agreement within 15 - 30% with the historical silk netting based correlations and show a substantial performance improvement when compared to previous testing performed using polyester netting and aluminum foil/fiberglass paper multilayer insulation. Additionally, the data further reinforce a recently observed trend that the heat flux is not directly proportional to the number of layers installed on a system. (paper)

Influence of the ion bombardment of O{sub 2} plasmas on low-k materials

Energy Technology Data Exchange (ETDEWEB)

Verdonck, Patrick, E-mail: verdonck@imec.be [IMEC, Kapeldreef 75, 3001 Leuven (Belgium); Samara, Vladimir [IMEC, Kapeldreef 75, 3001 Leuven (Belgium); Open University, Materials Engineering, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Goodyear, Alec [Open University, Materials Engineering, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Ferchichi, Abdelkarim; Van Besien, Els; Baklanov, Mikhail R. [IMEC, Kapeldreef 75, 3001 Leuven (Belgium); Braithwaite, Nicholas [Open University, Department of Physics and Astronomy, Walton Hall, Milton Keynes MK7 6AA (United Kingdom)

2011-10-31

In this study, special tests were devised in order to investigate the influence of ion bombardment on the damage induced in low-k dielectrics by oxygen plasmas. By placing a sample that suffered a lot of ion bombardment and one which suffered little ion bombardment simultaneously in the same plasma, it was possible to verify that ion bombardment in fact helped to protect the low-k film against oxygen plasma induced damage. Exhaustive analyses (ellipsometry, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, porosimetry, capacitance-voltage (C-V) measurements, water contact angle analysis) show that ion bombardment induced the formation of a denser top layer in the film, which then hampered further penetration of active oxygen species deeper into the bulk. This was further confirmed by other tests combining capacitively and inductively coupled plasmas. Therefore, it was possible to conclude that, at least for these plasmas, ion bombardment may help to reduce plasma induced damage to low-k materials.

Modification and structuring of conducting polymer films on insulating substrates by ion beam treatment

International Nuclear Information System (INIS)

Asmus, T.; Wolf, Gerhard K.

2000-01-01

Besides the commonly used procedures of UV-, X-ray and electron beam lithography, surface structuring by ion beam processes represents an alternative route to receive patterns in the nanometre-micrometre scale. In this work we focused on changes of surface properties of the polymer materials induced by ion irradiation and on reproducing hexagonal and square patterns in the micrometre scale. To achieve a better understanding of modification and structuring of insulating and conducting polymers by ion beam treatment we investigated effects of 14 keV Ar + bombardment on thin films of doped conducting polyethoxithiophene (PEOT) and polyethylenedioxithiophene (PEDT) on polyethersulfone (PES) as insulating substrate within the fluence range from 10 14 to 10 17 ions/cm 2 . Changes of surface properties like wettability, solubility, topology and electrochemical behaviour have been studied by contact angle technique, AFM/LFM, cyclovoltammetry and electrochemical microelectrode. By irradiation through copper masks structured patterns were achieved. These patterns can be converted by galvanic or electroless copper deposition in structured metal layers

Hybrid-type long-lived carbon stripper foils

International Nuclear Information System (INIS)

Sugai, Isao; Kato, Hajime

1989-01-01

A new method for the preparation of hybrid-type long-lived carbon stripper foils was developed. The new procedure is based on a modification of our controlled dc arc-discharge method. The carbon foils are of the multilayer type and the layers are composed of carbon particles emitted from the electrodes in the ac arc-discharge and from the cathode in the dc arc-discharge. With this simple and powerful method long lived carbon stripper foils can be prepared with higher reliability and reproducibility than with the previous procedure. (orig.)

Magnetoresistance and ion bombardment induced magnetic patterning

International Nuclear Information System (INIS)

Hoeink, V.

2008-01-01

In this thesis the combination of the magnetic patterning of the unidirectional anisotropy and the tunnel magnetoresistance effect is investigated. In my diploma thesis, it has been shown that it is in principle possible to use the magnetic patterning by ion bombardment to magnetically structure the pinned layer in magnetic tunnel junctions (MTJs) with alumina barrier. Furthermore, it has been shown that the side effects which have been observed after this treatment can be at least reduced by an additional heating step. Starting from this point, the applicability of ion bombardment induced magnetic patterning (IBMP) in general and the combination of IBMP and MTJs in particular is investigated and new applications are developed. (orig.)

Birefringence and dichroism of poly(vinyl-alcohol) foils containing phthalazinium ylids

Science.gov (United States)

Rogojanu, Alina; Dascalu, Carmen Felicia; Zelinschi, Beatrice Carmen; Caprosu, Maria; Dorohoi, Dana Ortansa

2011-10-01

Pure and colored with phthalazinium ylids poly(vinyl-alcohol) (PVA) foils were stretched under gentile heating. The birefringence of the thin foils was determined with a Babinet compensator standardized for yellow radiation of a Sodium lamp. The determined birefringence of the colored PVA foils is higher than that of the pure PVA foils. This fact indicates that the phthalazinium ylids facilitate the increase in the anisotropy of the stretched foils. The visible absorption electronic band of phthalazinium ylids was used to estimate the dichroic ratio and the degree of order of the ylid molecules in the stretched PVA foils. An increase in dichroism and birefringence with the degree of stretching has been evidenced for uncolored and colored PVA foils.

Carbon buildup monitoring using RBS: Correlation with secondary electrons

International Nuclear Information System (INIS)

Aguilera, E.F.; Rosales, P.; Martinez-Quiroz, E.; Murillo, G.; Fernandez, M.C.

2006-01-01

The RBS technique is applied to solve the problem of on-line monitoring of the carbon deposited on a thin backed foil under ion bombardment. An iterative method is used to reliably extract quantities such as number of projectiles and target thickness in spite of beam energy changes and detector unstabilities. Experimental values for secondary electron yields are also deduced. Results are reported for the thickness variation of thin carbon foils bombarded with carbon ions of energies between 8.95 and 13 MeV. A linear correlation of this variation is found with both, the ion fluence at target and the number of secondary electrons emitted. The correlation exists even though a wide range of beam currents, beam energies and bombarding times was used during the experiment. The measured electron yields show evidence for a change in the emission process between the original foils and the deposited layer, possibly due to a texture change

A thermal spike model of the amorphization of insulators by high-energy heavy-ion irradiation

International Nuclear Information System (INIS)

Szenes, G.

1995-01-01

Recently, experimental data on magnetic insulators irradiated with swift heavy ions were analyzed by a new thermal spike model and good quantitative agreement was achieved. Analytical expressions were given for the evolution of latent tracks with the electronic stopping power S e of bombarding ions and a relation between the thermal properties of the target and the threshold value of S e was proposed and proved experimentally. In the present paper, after a brief review of the model, the temperature dependence of latent track formation is discussed and the predictions of the model are compared with the available experimental results

Fertile transgenic wheat from microprojectile bombardment of scutellar tissue.

Science.gov (United States)

Becker, D; Brettschneider, R; Lörz, H

1994-02-01

A reproducible transformation system for hexaploid wheat was developed based on particle bombardment of scutellar tissue of immature embryos. Particle bombardment was carried out using a PDS 1000/He gun. Plant material was bombarded with the plasmid pDB1 containing the beta-glucuronidase gene (uidA) under the control of the actin-1 promoter of rice, and the selectable marker gene bar (phosphinothricin acetyltransferase) under the control of the CaMV 35S promoter. Selection was carried out using the herbicide Basta (Glufosinate-ammonium). From a total number of 1050 bombarded immature embryos, in seven independent transformation experiments, 59 plants could be regenerated. Putative transformants were screened for enzyme activity by the histochemical GUS assay using cut leaf material and by spraying the whole plants with an aqueous solution of the herbicide Basta. Twelve regenerants survived Basta spraying and showed GUS-activity. Southern-blot analysis indicated the presence of introduced foreign genes in the genomic DNA of the transformants and both marker genes were present in all plants analysed. To date, four plants have been grown to maturity and set seed. Histochemically stained pollen grains showed a 1:1 segregation of the uidA gene in all plants tested. A 3:1 segregation of the introduced genes was demonstrated by enzyme activity tests and Southern blot analysis of R1 plants.

BANGERTER FOILS IN THE POSTOPERATIVE MANAGEMENT OF ESOTROPIA.

Directory of Open Access Journals (Sweden)

Galina G. Dimitrova

2014-12-01

Full Text Available Purpose: To evaluate the application of Bangerter foils in the postoperative management of esotropia Methods: A retrospective study of 200 patients who underwent bimedial recessions for various forms of alternating/alternated esotropia in the period of 2000-2013. In the cases of residual postoperative angle, tendency of recurrence of strabismus and preferred fixation, Bangerter foil was fixed on the corrective glass of the dominant eye- either on the next day of surgery, or on the 10-th postoperative day and was in use for at least 6 months. Results: Bangerter foils were applied in 67(35,1% under corrected patients with a mean residual angle for near 7,01±3,51Δ. Mean residual angle in patients without foils was 3,47±4,06Δ (p<0,001. Statistically significant factors in patients with filters were amblyopia treatment before surgery (p<0,001, anisometropia (p=0,003 and type of esotropia (accommodative vs. non accommodative (p<0,001. Within the group without filters there was a significant increase of the residual angle for near on the third (p<0,001 and sixth month (p=0,036, while within the group with foils angle was not significantly changed (p=0,325; p=0,058 with time. In the group with foils no cases with relapse of strabismus and amblyopia were recorded and even a decrease of the postoperative angle was clinically observed in some patients. Conclusion: To our experience Bangerter foils are a reliable tool in the postoperative management of undercorrected esotropia.

Analysis of Mechanical Properties for GEM Foil

CERN Document Server

Chin, Yuk Ming

2016-01-01

In view of new assembly technique of the GEM detector; in which three foils stack is stretched to get the uniform gaps among the foils. We studied the mechanical properties of the foil material. We conditioned the samples in different environments to make them extra dry and wet. As holes are the major source of the charge amplification their deformation can effect the detector performance. Therefore in our studies we also studied at which level of the stress the holes deformation is seen. These tensile and holes deformation studies can help to optimize the stress during detector assembly.

Hydrogen permeation through metallic foils

International Nuclear Information System (INIS)

Bernardi, M.I.B.; Rodrigues, J.A.

1987-01-01

The process of electrolytic permeation of hydrogen through metallic foils is studied. A double electrolytic cell, in glass, in which the two compartments of reaction are separated by a metallic foil to be studied, was built. As direct result, the hydrogen diffusion coefficient in the metal is obtained. The hydrogen diffusion coefficients in the palladium and, in austenitic stainless steels 304 and 304 L, used in the Angra-1 reactor, were obtained. Samples of stainless steels with and without welding, were used. (Author) [pt

Evolution of atomic-scale surface structures during ion bombardment: A fractal simulation

International Nuclear Information System (INIS)

Shaheen, M.A.; Ruzic, D.N.

1993-01-01

Surfaces of interest in microelectronics have been shown to exhibit fractal topographies on the atomic scale. A model utilizing self-similar fractals to simulate surface roughness has been added to the ion bombardment code TRIM. The model has successfully predicted experimental sputtering yields of low energy (less then 1000 eV) Ar on Si and D on C using experimentally determined fractal dimensions. Under ion bombardment the fractal surface structures evolve as the atoms in the collision cascade are displaced or sputtered. These atoms have been tracked and the evolution of the surface in steps of one monolayer of flux has been determined. The Ar--Si system has been studied for incidence energies of 100 and 500 eV, and incidence angles of 0 degree, 30 degree, and 60 degree. As expected, normally incident ion bombardment tends to reduce the roughness of the surface, whereas large angle ion bombardment increases the degree of surface roughness. Of particular interest though, the surfaces are still locally self-similar fractals after ion bombardment and a steady state fractal dimension is reached, except at large angles of incidence

Hydrogen pumping and release by graphite under high flux plasma bombardment

International Nuclear Information System (INIS)

Hirooka, Y.; Leung, W.K.; Conn, R.W.; Goebel, D.M.; Labombard, B.; Nygren, R.; Wilson, K.L.

1988-01-01

Inert gas (helium or argon) plasma bombardment has been found to increase the surface gas adsorptivity of isotropic graphite (POCO-graphite), which can then getter residual gases in a high vacuum system. The inert gas plasma bombardment was carried out at a flux ∼ 1 x 10 18 ions s -1 cm -2 to a fluence of the order of 10 21 ions/cm 2 and at temperatures around 800 degree C. The plasma bombarding energy was varied between 100 and 200 eV. The gettering speed of the activated graphite surface is estimated to be as large as 25 liters s -1 cm -2 at total pressures between 10 -6 and 10 -7 torr. The gettering capacity estimated is 0.025 torr-liter/cm 2 at room temperature. The gettering capability of graphite can be easily recovered by repeating inert gas plasma bombardment. The activated graphite surface exhibits a smooth, sponge-like morphology with significantly increased pore openings, which correlates with the observed increase in the surface gas adsorptivity. The activated graphite surface has been observed to pump hydrogen plasma particles as well. From calibrated H-alpha measurements, the dynamic hydrogen retention capacity is evaluated to be as large as 2 x 10 18 H/cm 2 at temperatures below 100 degree C and at a plasma bombarding energy of 300 eV

P-type diamond stripper foils for tandem ion accelerators

International Nuclear Information System (INIS)

Phelps, A.W.; Koba, R.

1989-01-01

The authors are developing a stripper foil composed of a p-type diamond membrane. This diamond stripper foil should have a significantly longer lifetime than any conventional stripper foil material. To be useful for stripper foils, the boron-doped blue diamond films must be thinner than 0.8 μm and pore-free. Two methods are compared for their ability to achieve a high nucleation areal density on a W substrate. Some W substrates were first coated with think layer of boron (≤20 nm) in order to enhance nucleation. Other W substrates were scratched with submicron diamond particles. A schematic diagram of the stripper foil is shown. Stripper foils were created by etching away the central area of W substrates. The diamond membrane was then supported by an annulus of W. Tungsten was selected as a ring-support material because of its high electrical and thermal conductivity, relatively low thermal expansion, and proven suitability as a substrate for diamond CVD. Warping or fracture of the diamond film after substrate etch-back was investigated

Automatic spark counting of alpha-tracks in plastic foils

International Nuclear Information System (INIS)

Somogyi, G.; Medveczky, L.; Hunyadi, I.; Nyako, B.

1976-01-01

The possibility of alpha-track counting by jumping spark counter in cellulose acetate and polycarbonate nuclear track detectors was studied. A theoretical treatment is presented which predicts the optimum residual thickness of the etched foils in which completely through-etched tracks (i.e. holes) can be obtained for alpha-particles of various energies and angles of incidence. In agreement with the theoretical prediction it is shown that a successful spark counting of alpha-tracks can be performed even in polycarbonate foils. Some counting characteristics, such as counting efficiency vs particle energy at various etched foil thicknesses, surface spark density produced by electric breakdowns in unexposed foils vs foil thickness, etc. have been determined. Special attention was given to the spark counting of alpha-tracks entering thin detectors at right angle. The applicability of the spark counting technique is demonstrated in angular distribution measurements of the 27 Al(p,α 0 ) 24 Mg nuclear reaction at Ep = 1899 keV resonance energy. For this study 15 μm thick Makrofol-G foils and a jumping spark counter of improved construction were used. (orig.) [de

Impact and spreading behavior of cluster atoms bombarding substrates

Energy Technology Data Exchange (ETDEWEB)

Fang, Te-Hua, E-mail: fang.tehua@msa.hinet.net [Institute of Mechanical and Electromechanical Engineering, National Formosa University, Yunlin 632, Taiwan (China); Kang, Shao-Hui; Liao, Jia-Hung [Institute of Mechanical and Electromechanical Engineering, National Formosa University, Yunlin 632, Taiwan (China)

2009-12-15

The purpose of this study is to investigate the behavior of copper cluster atoms bombarding a substrate using molecule dynamics based on tight-binding second moment approximation (TB-SMA) potential. The simulated results show that a crater on the substrate surface was created by the impact of the clusters. The variations of kinetic energy of cluster bombardments can be divided into three stages. At the initial impact level, the kinetic energies of the clusters and the substrate were constant. Then, the system went into a sluggish stage of energy variation, in which the kinetic energy of the clusters reduced. In the final stage, the kinetic energy of the system became stable. The high slip vector region around the crater had a disorder damage zone. The symmetry-like cross-slip occurred beneath the top layer of the substrate along the <1 1 0> orientations. The spreading index, temperature, and potential functions that affect the bombardments are also discussed.

Impact and spreading behavior of cluster atoms bombarding substrates

International Nuclear Information System (INIS)

Fang, Te-Hua; Kang, Shao-Hui; Liao, Jia-Hung

2009-01-01

The purpose of this study is to investigate the behavior of copper cluster atoms bombarding a substrate using molecule dynamics based on tight-binding second moment approximation (TB-SMA) potential. The simulated results show that a crater on the substrate surface was created by the impact of the clusters. The variations of kinetic energy of cluster bombardments can be divided into three stages. At the initial impact level, the kinetic energies of the clusters and the substrate were constant. Then, the system went into a sluggish stage of energy variation, in which the kinetic energy of the clusters reduced. In the final stage, the kinetic energy of the system became stable. The high slip vector region around the crater had a disorder damage zone. The symmetry-like cross-slip occurred beneath the top layer of the substrate along the orientations. The spreading index, temperature, and potential functions that affect the bombardments are also discussed.

Forming of electron beams from a betatron by foils scatterers

Energy Technology Data Exchange (ETDEWEB)

Kozlov, A P; Shishov, V A [N.N. Petrov Research Inst. of Oncology, Leningrad (USSR). Laboratory of High Energics

1976-12-01

The technique of forming electron beams by one scattering foil and one compensating foil is discussed. This method provides a means for producing large-size uniform dose distributions with much smaller losses in dose rate as compared with conventional beam forming by ine foil. Moreover, the energy losses involved in this process and the background of concomitant bremsstrahlung are much less. A techinque of calculation to determine approximate parameters of the compensating foils is described.

Method of fabricating a uranium-bearing foil

Science.gov (United States)

Gooch, Jackie G [Seymour, TN; DeMint, Amy L [Kingston, TN

2012-04-24

Methods of fabricating a uranium-bearing foil are described. The foil may be substantially pure uranium, or may be a uranium alloy such as a uranium-molybdenum alloy. The method typically includes a series of hot rolling operations on a cast plate material to form a thin sheet. These hot rolling operations are typically performed using a process where each pass reduces the thickness of the plate by a substantially constant percentage. The sheet is typically then annealed and then cooled. The process typically concludes with a series of cold rolling passes where each pass reduces the thickness of the plate by a substantially constant thickness amount to form the foil.

Light Barrier for Non-Foil Packaging

Science.gov (United States)

2010-12-16

foil and all-plastic materials were retorted and a second set of all-plastic packaged entrees were Microwave Sterilized on the Washington State...Copolymers for Retort Applications; SPE Polyolefins and Flexible Packaging Conference: Society of Plastics Engineers. Newtown. CT, 43pp. Thellen C...Final Scientific Report Light Barrier for Non-Foil Packaging Contract No. W911QY-08-C-0132 Final Scientific Report Contract No. W911QY-08-C-0132

Self-Assembled Gold Nano-Ripple Formation by Gas Cluster Ion Beam Bombardment.

Science.gov (United States)

Tilakaratne, Buddhi P; Chen, Quark Y; Chu, Wei-Kan

2017-09-08

In this study, we used a 30 keV argon cluster ion beam bombardment to investigate the dynamic processes during nano-ripple formation on gold surfaces. Atomic force microscope analysis shows that the gold surface has maximum roughness at an incident angle of 60° from the surface normal; moreover, at this angle, and for an applied fluence of 3 × 10 16 clusters/cm², the aspect ratio of the nano-ripple pattern is in the range of ~50%. Rutherford backscattering spectrometry analysis reveals a formation of a surface gradient due to prolonged gas cluster ion bombardment, although the surface roughness remains consistent throughout the bombarded surface area. As a result, significant mass redistribution is triggered by gas cluster ion beam bombardment at room temperature. Where mass redistribution is responsible for nano-ripple formation, the surface erosion process refines the formed nano-ripple structures.

Method of stabilizing Nb3Sn superconducting foils

International Nuclear Information System (INIS)

Kruzliak, J.; Lences, P.; Allarova, H.

1982-01-01

The stabilization of niobium-tin Nb 3 Sn superconducting foils with copper is carried out by deposition or by diffusion in pure copper or in a tin bath containing different copper levels, with the surface etched or unetched. The foils are covered with a copper film at a temperature of 300 to 5O0 degC using a tin solder, spread on a copper, silver or nickel layer deposited on the foil surface from solutions for electroless plating. The bond between the surface of the superconducting foil and the electroless plated metal layer is annealed in a controlled atmosphere or in a vacuum at a temperature of 200 to 500 degC for over 20 to 60 minutes. The copper stabilization layer can also be produced electrolytically. (J.B.)

Ion bombardment induced ripple topography on amorphous solids

International Nuclear Information System (INIS)

Carter, G.; Nobes, M.J.; Paton, F.; Williams, J.S.

1977-01-01

Earlier studies of the ion bombardment induced ripple morphology on the surfaces of amorphous solids when compared with geomorphological effects are shown to possess many similar features. The present study, with 40 keV Ar + ion bombarded Si suggests that analogies are incomplete, however, and that greater similarities with the process of macroscopic sandblasting (corrosion) exist. It is shown that the genesis of wave like structures on Si is from isolated features, which have the appearance of ripple trains, which are faceted. It is suggested that these features result from particle flux enhancement processes near surface dimples generated by stress induced surface lifting. (author)

The stripping foil test stand in the Linac4 transfer line

CERN Document Server

Weterings, W; Noulibos, R; Sillanoli, Y; van Trappen, P

2015-01-01

The 160 MeV H− beam from the Linac4 (L4) linear accelerator at CERN will be injected into the proton synchrotron booster (PSB) with a new H− charge-exchange injection system. It will include a stripping foil, to convert H− into protons by stripping off the electrons. To gain experience with these very fragile foils, prior to the installation in the PSB, and test different foil materials and thicknesses, lifetimes of the foils, the foil changing mechanism and interlocking functions, a stripping foil test stand will be installed in the L4 transfer line in 2015. This paper describes the mechanical design of the system and discusses the test possibilities and parameters.

The stripping foil test stand in the Linac4 transfer line

International Nuclear Information System (INIS)

Weterings, W.; Bracco, C.; Noulibos, R.; Sillanoli, Y.; Trappen van, P.

2015-01-01

The 160 MeV H - beam from the Linac4 (L4) linear accelerator at CERN will be injected into the proton synchrotron booster (PSB) with a new H - charge-exchange injection system. It will include a stripping foil, to convert H - into protons by stripping off the electrons. To gain experience with these very fragile foils, prior to the installation in the PSB, and test different foil materials and thicknesses, lifetimes of the foils, the foil changing mechanism and interlocking functions, a stripping foil test stand will be installed in the L4 transfer line in 2015. This paper describes the mechanical design of the system and discusses the test possibilities and parameters. (author)

Gas electron multiplier (GEM) foil test, repair and effective gain calculation

Science.gov (United States)

Tahir, Muhammad; Zubair, Muhammad; Khan, Tufail A.; Khan, Ashfaq; Malook, Asad

2018-06-01

The focus of my research is based on the gas electron multiplier (GEM) foil test, repairing and effective gain calculation of GEM detector. During my research work define procedure of GEM foil testing short-circuit, detection short-circuits in the foil. Study different ways to remove the short circuits in the foils. Set and define the GEM foil testing procedures in the open air, and with nitrogen gas. Measure the leakage current of the foil and applying different voltages with specified step size. Define the Quality Control (QC) tests and different components of GEM detectors before assembly. Calculate the effective gain of GEM detectors using 109Cd and 55Fe radioactive source.

Study of the electronic structure of pure aluminium, aluminium oxide and nitride by spectroscopy of electrons excited under electronic and photonic bombardment (X and UV)

International Nuclear Information System (INIS)

Gautier-Soyer, Martine

1985-01-01

This research thesis reports the use of electron spectroscopy with electrons excited under electronic or photonic (X or UV) bombardment for the study of electronic state density of aluminium, aluminium oxide (Al 2 O 3 ) and aluminium nitride (AlN). The objective is to get an insight into phenomena related to technological problems of adherence, wear, lubrication, corrosion or breakdown met in metals, insulators and semiconductors. The author highlighted the presence of occupied surface states on Al(111) and Al(100), and electronic levels localised in the forbidden band of Al 2 O 3 and AlN, induced by structural defects which promote surface reactivity [fr

Ion peening and stress relaxation induced by low-energy atom bombardment of covalent solids

International Nuclear Information System (INIS)

Koster, Monika; Urbassek, Herbert M.

2001-01-01

Using molecular-dynamics simulation, we study the buildup and relaxation of stress induced by low-energy (≤150 eV) atom bombardment of a target material. The effect is brought out most clearly by using an initially compressed specimen. As target material, we employ Si, based on the Tersoff potential. By varying the bond strength in the potential, we can specifically study its effect on damage production and stress changes. We find that in general, stress is relaxed by the atom bombardment; only for low bombarding energies and strong bonds, atom bombardment increases stress. We rationalize this behavior by considering the role of energized atoms and of recoil-implanted target atoms

Direct growth of hexagonal boron nitride/graphene heterostructures on cobalt foil substrates by plasma-assisted molecular beam epitaxy

Energy Technology Data Exchange (ETDEWEB)

Xu, Zhongguang; Khanaki, Alireza; Tian, Hao; Zheng, Renjing; Suja, Mohammad; Liu, Jianlin, E-mail: jianlin@ece.ucr.edu [Quantum Structures Laboratory, Department of Electrical and Computer Engineering, University of California, Riverside, California 92521 (United States); Zheng, Jian-Guo [Irvine Materials Research Institute, University of California, Irvine, California 92697-2800 (United States)

2016-07-25

Graphene/hexagonal boron nitride (G/h-BN) heterostructures have attracted a great deal of attention because of their exceptional properties and wide variety of potential applications in nanoelectronics. However, direct growth of large-area, high-quality, and stacked structures in a controllable and scalable way remains challenging. In this work, we demonstrate the synthesis of h-BN/graphene (h-BN/G) heterostructures on cobalt (Co) foil by sequential deposition of graphene and h-BN layers using plasma-assisted molecular beam epitaxy. It is found that the coverage of h-BN layers can be readily controlled on the epitaxial graphene by growth time. Large-area, uniform-quality, and multi-layer h-BN films on thin graphite layers were achieved. Based on an h-BN (5–6 nm)/G (26–27 nm) heterostructure, capacitor devices with Co(foil)/G/h-BN/Co(contact) configuration were fabricated to evaluate the dielectric properties of h-BN. The measured breakdown electric field showed a high value of ∼2.5–3.2 MV/cm. Both I-V and C-V characteristics indicate that the epitaxial h-BN film has good insulating characteristics.

Diffusion processes in bombardment-induced surface topography

International Nuclear Information System (INIS)

Robinson, R.S.

1984-01-01

The bombardment of surfaces with moderate energy ions can lead to the development of various micron-sized surface structures. These structures include ridges, ledges, flat planes, pits and cones. The causal phenomena in the production of these features are sputtering, ion reflection, redeposition of sputtered material, and surface diffusion of both impurity and target-atom species. The authors concentrate on the formation of ion bombardment-induced surface topography wherein surface diffusion is a dominant process. The most thoroughly understood aspect of this topography development is the generation of cone-like structures during sputtering. The formation of cones during sputtering has been attributed to three effects. These are: (1) the presence of asperities, defects, or micro-inclusions in the surface layers, (2) the presence of impurities on the surfaces, and (3) particular crystal orientations. (Auth.)

Interaction of relativistic H- ions with thin foils

International Nuclear Information System (INIS)

Mohagheghi, A.H.

1990-09-01

The response of relativistic H - ions to thin carbon foils was investigated for beam energies ranging from 226 MeV to 800 MeV. For the foil thicknesses we have studied, ranging from 15 to 300 μg/cm 2 , an appreciable fraction of the H - beam survives intact, some H - ions are stripped down to protons, and the remainder is distributed over the states of H 0 . This experiment is different from the low energy studies in that the projectile velocity is comparable to the speed of light, leading to an interaction time of typically less than a femtosecond. The present results challenge the theoretical understanding of the interaction mechanisms. An electron spectrometer was used to selectively field-ionize the Rydberg states, 9 < n < 17, at beam energies of 581 MeV and 800 MeV. The yield of low-lying states were measured by Doppler tuning a Nd:YAG laser to excite transitions to a Rydberg state which was then field-ionized and detected. A simple model is developed to fit the yield of each state as a function of foil thickness. The simple model is successful in predicting the general features of the yield data. However, the data are suggestive of a more complex structure in the yield curves. The yield of a given state depends strongly on the foil thickness, demonstrating that the excited states are formed during the passage of the ions through a foil. The optimum thickness to produce a given state increases with the principal quantum number of the state suggesting an excitation process which is at least pratially stepwise. The results of a Monte Carlo simulation are compared with the experimental data to estimate the distribution of the excited states coming out of a foil. The distributions of the excited states and their dependence on foil thickness are discussed

Excited-atom production by electron and ion bombardment of alkali halides

International Nuclear Information System (INIS)

Walkup, R.E.; Avouris, P.; Ghosh, A.P.

1987-01-01

We present experimental results on the production of excited atoms by electron and ion bombardment of alkali halides. For the case of electron bombardment, Doppler shift measurements show that the electronically excited atoms have a thermal velocity distribution in equilibrium with the surface temperature. Measurements of the absolute yield of excited atoms, the distribution of population among the excited states, and the systematic dependence on incident electron current and sample temperature support a model in which the excited atoms are produced by gas-phase collisions between desorbed ground-state atoms and secondary electrons. In contrast, for the case of ion bombardment, the excited atoms are directly sputtered from the surface, with velocity distributions characteristic of a collision cascade, and with typical energies of --10 eV

The crystalline-to-amorphous transition in ion-bombarded silicon

International Nuclear Information System (INIS)

Mueller, G.; Kalbitzer, S.

1980-01-01

Hydrogen-free, but defect-rich a-Si can be obtained by ion bombardment of c-Si. The formation of such material has been studied in detail using carrier-removal measurements in the characterization of the bombardment damage. In order to develop an overall view of the disordering process these data are discussed together with results obtained on similar films by Rutherford back-scattering, electron spin resonance, electron microscopy and optical measurements. It is concluded that amorphous material generally evolves from an intermediate crystalline phase supersaturated with point defects. The transition occurs locally at the sites of energetic ion impacts into critically predamaged crystalline material. As a consequence, an amorphous layer is built up from small clusters with dimensions typically of the order of 50 A. From the net expansion of the bombarded layers it is concluded that regions of lower atomic density are locally present, very likely a consequence of a structural mismatch between individual amorphous clusters. In this way a heterogeneous defect structure may build up in these films which determines their electronic properties. (author)

Secondary electron emission of thin carbon foils under the impact of hydrogen atoms, ions and molecular ions, under energies within the MeV range

International Nuclear Information System (INIS)

Vidovic, Z.

1997-06-01

This work focuses on the study of the emission statistics of secondary electrons from thin carbon foils bombarded with H 0 , H 2 + and H 3 + projectiles in the 0.25-2.2 MeV energy range. The phenomenon of secondary electron emission from solids under the impact of swift ions is mainly due to inelastic interactions with target electrons. The phenomenological and theoretical descriptions, as well as a summary of the main theoretical models are the subject of the first chapter. The experimental set-up used to measure event by event the electron emission of the two faces of a thin carbon foil traversed by an energetic projectile is described in the chapter two. In this chapter are also presented the method and algorithms used to process experimental spectra in order to obtain the statistical distribution of the emitted electrons. Chapter three presents the measurements of secondary electron emission induced by H atoms passing through thin carbon foils. The secondary electron yields are studied in correlation with the emergent projectile charge state. We show the peculiar role of the projectile electron, whether it remains or not bound to the incident proton. The fourth chapter is dedicated to the secondary electron emission induced by H 2 + and H 3 + polyatomic ions. The results are interpreted in terms of collective effects in the interactions of these ions with solids. The role of the proximity of the protons, molecular ion fragments, upon the amplitude of these collective effects is evidenced from the study of the statistics of forward emission. These experiences allowed us to shed light on various aspects of atom and polyatomic ion inter-actions with solid surfaces. (author)

Design of foil implosion system for Pioneer I experiments

International Nuclear Information System (INIS)

Erickson, D.J.; Caird, R.S.; Fowler, C.M.

1985-01-01

A foil implosion system is described that integrates an explosive flux-compression generator, a flat plate feed section with power conditioning switches, and a vacuum electrode region containing a cylindrical foil/plasma load. Power conditioning, obtained with an explosive-driven plasma compression opening switch and explosive-actuated closing switches, provides a submicrosecond multimegampere pulse for the implosion of an aluminum plasma. The flat plate section is configured for bidirectional feed to the coaxial vacuum electrodes. Important considerations in the design of the vacuum power flow region include gap failure, feed symmetry, and radial diagnostic access. The system presently accommodates a foil radius of 3 cm. Innovative foil insertion and clamping techniques are also described

Effects of film/foil interactions on X-ray image quality - experimental studies

International Nuclear Information System (INIS)

Maurer, H.J.; Goos, F.

1985-01-01

When assessing the quality of X-ray images, the interaction between film and foil should never be left out of account. Except for the case of green-emitting foils which require green-emitting films, films and foils are normally regarded separately, so that many variations are possible. The authors review the interaction between film and foil under practical aspects. Studies published so far have concentrated either on the amplification factor of foils or an the object imaging characteristics of certain films. Systematic studies on the interaction between film and foil have never been carried out. (orig.) [de

The effects of thermal annealing on iron bombarded InP/InGaAs multilayer structures

International Nuclear Information System (INIS)

Subramaniam, S.C.; Rezazadeh, A.A.

2006-01-01

The effects of Fe-ion bombardment at 77 K (cold) and room temperature (RT) into single layer InGaAs, InP and multilayer InP/InGaAs HBT structures have been investigated. Annealing characteristics and RF dissipation loss measurements of Fe-ion bombarded samples at 77 K indicated good electrical isolation in n-, p-type InGaAs materials and InP/InGaAs HBT structures. Thermally stable (up to 250 deg. C) high sheet resistance (R sh ) of ∼5 x 10 6 Ω/sq has been achieved on these samples while higher R sh of ∼10 7 Ω/sq was obtained for the n-InP materials bombarded with similar conditions. Dissipation losses of 1.7 dB/cm at 10 GHz and 2.8 dB/cm at 40 GHz have been measured for the cold Fe-ion bombarded InP-based HBT structures. This result is similar to those obtained for an un-bombarded S.I. InP substrate, indicating good electrical isolation. We have also determined electron trapping levels by thermal annealing for the cold and RT Fe-ion bombarded samples. It is shown that the high resistivity achieved in the cold implanted InGaAs layer is most likely due to the creation of mid-bandgap defect levels (E C - 0.33) eV, which are created only in the cold Fe-ion bombardment. The DC isolation and RF dissipation loss analysis have been used to identify a suitable bombardment scheme for the fabrication of planar InP/InGaAs HBTs

Scaling laws for radial foil bearings

Science.gov (United States)

Honavara Prasad, Srikanth

The effects of fluid pressurization, structural deformation of the compliant members and heat generation in foil bearings make the design and analysis of foil bearings very complicated. The complex fluid-structural-thermal interactions in foil bearings also make modeling efforts challenging because these phenomena are governed by highly non-linear partial differential equations. Consequently, comparison of various bearing designs require detailed calculation of the flow fields (velocities, pressures), bump deflections (structural compliance) and heat transfer phenomena (viscous dissipation in the fluid, frictional heating, temperature profile etc.,) resulting in extensive computational effort (time/hardware). To obviate rigorous computations and aid in feasibility assessments of foil bearings of various sizes, NASA developed the "rule of thumb" design guidelines for estimation of journal bearing load capacity. The guidelines are based on extensive experimental data. The goal of the current work is the development of scaling laws for radial foil bearings to establish an analytical "rule of thumb" for bearing clearance and bump stiffness. The use of scale invariant Reynolds equation and experimentally observed NASA "rule of thumb" yield scale factors which can be deduced from first principles. Power-law relationships between: a. Bearing clearance and bearing radius, and b. bump stiffness and bearing radius, are obtained. The clearance and bump stiffness values obtained from scaling laws are used as inputs for Orbit simulation to study various cases. As the clearance of the bearing reaches the dimensions of the material surface roughness, asperity contact breaks the fluid film which results in wear. Similarly, as the rotor diameter increases (requiring larger bearing diameters), the load capacity of the fluid film should increase to prevent dry rubbing. This imposes limits on the size of the rotor diameter and consequently bearing diameter. Therefore, this thesis aims

Health status of cows fed maize silage covered with oxo-biodegradable foil

OpenAIRE

Piotr SZTERK; Piotr DORSZEWSKI; Małgorzata GRABOWICZ; Lucyna PODKÓWKA

2017-01-01

In agricultural practice, silage production uses pure, low density polyethylene foil. This foil, after use, becomes farm waste, having a negative impact on the environment. Instead of conventional foil, an environmentally safe biodegradable foil can be used, made from naturally occurring polymers or from synthetic multiparticulates, easily degradable by microorganisms. Silage covered with this type of foil should be safe for animal health. The purpose of the study was to determine whether oxo...

Preliminary report into the effects of nitrogen ion bombardment treatment on mustard seeds

International Nuclear Information System (INIS)

Smith, C.W.; Al-Hashmi, S.A.R.; Ahmed, N.A.G.; Pollard, M.

1988-01-01

Mustard seeds have been subjected to nitrogen ion bombardment. A range of conditions was found within which there was an enhancement in the growth of seedlings from the ion bombardment treated seeds relative to those grown from control seeds. Scanning electron microscopy was used to examine seeds after treatment. It appeared that there had been an etching of the seed coating by the ion bombardment. This view was supported by experiments which showed that the rate of capillary water uptake by the treated seeds had been enhanced. (author)

Dating Howardite Melt Clasts: Evidence for an Extended Vestan Bombardment?

Science.gov (United States)

Cartwright, J. A.; Hodges, K. V.; Wadhwa, M.; Mittlefehldt, D. W.

2016-01-01

Howardites are polymict breccias that, together with eucrites and diogenites (HED), likely originate from the vestan surface (regolith/ megaregolith), and display a heterogeneous distribution of eucritic and diogenitic material. Melt clasts are also present alongside other regolithic features within howardites, and are noteworthy for their compositional variability and appearance. Melt clasts formed by impact events provide a snapshot of the timings and conditions of surface gardening and bombardment on the vestan surface. By dating such clasts, we aim to better constrain the timings of impact events on Vesta, and to establish whether the impact flux in the asteroid belt was similar to that on the Moon. As the Moon is used as the basis for characterising impact models of the inner solar system, it is necessary to verify that apparent wide-scale events are seen in other planetary bodies. In particular, the observed clustering of Apollo melt clast ages between 3.8-4.0 Ga has led to two hypotheses: 1) The Moon was subjected to a sudden event - 'Lunar Cataclysm' or period of 'Late Heavy Bombardment' (LHB), 2) The age cluster represents the end of an epoch of declining bombardment or 'Heavy Bombardment. No consensus has emerged regarding one or other hypothesis. We are testing these hypotheses by seeking evidence for such events in materials other than those derived from the Moon.

A suspended boron foil multi-wire proportional counter neutron detector

Energy Technology Data Exchange (ETDEWEB)

Nelson, Kyle A.; Edwards, Nathaniel S.; Hinson, Niklas J.; Wayant, Clayton D.; McGregor, Douglas S.

2014-12-11

Three natural boron foils, approximately 1.0 cm in diameter and 1.0 µm thick, were obtained from The Lebow Company and suspended in a multi-wire proportional counter. Suspending the B foils allowed the alpha particle and Li ion reaction products to escape simultaneously, one on each side of the foil, and be measured concurrently in the gas volume. The thermal neutron response pulse-height spectrum was obtained and two obvious peaks appear from the 94% and 6% branches of the {sup 10}B(n,α){sup 7}Li neutron reaction. Scanning electron microscope images were collected to obtain the exact B foil thicknesses and MCNP6 simulations were completed for those same B thicknesses. Pulse-height spectra obtained from the simulations were compared to experimental data and matched well. The theoretical intrinsic thermal–neutron detection efficiency for enriched {sup 10}B foils was calculated and is presented. Additionally, the intrinsic thermal neutron detection efficiency of the three natural B foils was calculated to be 3.2±0.2%.

A suspended boron foil multi-wire proportional counter neutron detector

Science.gov (United States)

Nelson, Kyle A.; Edwards, Nathaniel S.; Hinson, Niklas J.; Wayant, Clayton D.; McGregor, Douglas S.

2014-12-01

Three natural boron foils, approximately 1.0 cm in diameter and 1.0 μm thick, were obtained from The Lebow Company and suspended in a multi-wire proportional counter. Suspending the B foils allowed the alpha particle and Li ion reaction products to escape simultaneously, one on each side of the foil, and be measured concurrently in the gas volume. The thermal neutron response pulse-height spectrum was obtained and two obvious peaks appear from the 94% and 6% branches of the 10B(n,α)7Li neutron reaction. Scanning electron microscope images were collected to obtain the exact B foil thicknesses and MCNP6 simulations were completed for those same B thicknesses. Pulse-height spectra obtained from the simulations were compared to experimental data and matched well. The theoretical intrinsic thermal-neutron detection efficiency for enriched 10B foils was calculated and is presented. Additionally, the intrinsic thermal neutron detection efficiency of the three natural B foils was calculated to be 3.2±0.2%.

Dosimetric response of united, commercially available CTA foils for 60Co gamma rays

International Nuclear Information System (INIS)

Peimel-Stuglik, Z.

2001-01-01

The usefulness of two kinds of untinted CTA foils: Fuji CTR-125 dosimetric foil and technical CTA-T foil, produced by 'Zaklady Chemiczne, 'Gorzow Wielkopolski' as support for light-sensitive layers of amateur photo-films, for 60 Co gamma ray dosimetry was investigated. In spite of rather bad physical parameters of the technical foil (spread of foil thickness, high and different initial absorbance) the dosimetric response of both foils for 60 Co gamma rays was similar. The CTA-T foil can be used for routine dosimetry providing that dosimetric signals have to be calculated exactly as recommended by the ASTM (American Society for Testing and Materials) standard, i.e. as the difference of absorbance of irradiated and (the same) non-irradiated foil. Any other approach may lead to high errors of dose evaluation. The last is true also for other CTA foils, especially after long self-life. (author)

Development, characterization and qualification of first GEM foils produced in India

Science.gov (United States)

Shah, Aashaq; Ahmed, Asar; Gola, Mohit; Sharma, Ram Krishna; Malhotra, Shivali; Kumar, Ashok; Naimuddin, Md.; Menon, Pradeep; Srinivasan, K.

2018-06-01

The increasing demand for Gas Electron Multiplier (GEM) foils has been driven by their application in many current and proposed high-energy physics experiments. Micropack, a Bengaluru-based company, has established and commercialized GEM foils for the first time in India. Micropack used the double-mask etching technique to successfully produce 10 cm × 10 cm GEM foil. In this paper, we report on the development as well as the geometrical and electrical properties of these foils, including the size uniformity of the holes and leakage current measurements. Our characterization studies show that the foils are of good quality and satisfy all the necessary quality control criteria.

Positron annihilation lifetime spectroscopy study of Kapton thin foils

Science.gov (United States)

Kanda, G. S.; Ravelli, L.; Löwe, B.; Egger, W.; Keeble, D. J.

2016-01-01

Variable energy positron annihilation lifetime spectroscopy (VE-PALS) experiments on polyimide material Kapton are reported. Thin Kapton foils are widely used in a variety of mechanical, electronic applications. PALS provides a sensitive probe of vacancy-related defects in a wide range of materials, including open volume in polymers. Varying the positron implantation energy enables direct measurement of thin foils. Thin Kapton foils are also commonly used to enclose the positron source material in conventional PALS measurements performed with unmoderated radionuclide sources. The results of depth-profiled positron lifetime measurements on 7.6 μm and 25 μm Kapton foils are reported and determine a dominant 385(1) ps lifetime component. The absence of significant nanosecond lifetime component due to positronium formation is confirmed.

Ti foil light in the ATA [Advanced Test Accelerator] beam

International Nuclear Information System (INIS)

Slaughter, D.R.; Chong, Y.P.; Goosman, D.R.; Rule, D.W.; Fiorito, R.B.

1987-09-01

An experiment is in progress to characterize the visible light produced when a Ti foil is immersed in the ATA 2 kA, 43 MeV beam. Results obtained to date indicate that the optical condition of the foil surface is a critical determinant of these characteristics, with a very narrow angular distribution obtained when a highly polished and flat foil is used. These data are consistent with the present hypothesis that the light is produced by transition radiation. Incomplete experiments to determine the foil angle dependence of the detected light and its polarization are summarized and remaining experiments are described

Apparatus and process for ultrasonic seam welding stainless steel foils

Science.gov (United States)

Leigh, Richard W.

1992-01-01

An ultrasonic seam welding apparatus having a head which is rotated to form contact, preferably rolling contact, between a metallurgically inert coated surface of the head and an outside foil of a plurality of layered foils or work materials. The head is vibrated at an ultrasonic frequency, preferably along a longitudinal axis of the head. The head is constructed to transmit vibration through a contacting surface of the head into each of the layered foils. The contacting surface of the head is preferably coated with aluminum oxide to prevent the head from becoming welded to layered stainless steel foils.

Thermohydrodynamic analysis of airfoil bearing based on bump foil structure

Directory of Open Access Journals (Sweden)

S.Y. Maraiy

2016-09-01

Full Text Available The load carrying capacity of the gas foil bearing depends on the material properties and the configuration of the underlying bump strip’s structure. This paper presents three different cases for selecting the dimensions of the foil bearing to guarantee the highest possible load carrying capacity. It focuses on three main parameters that affect the compliance number; these parameters are the length of bump in θ direction, the pitch of bump foil, and the thickness of bump foil. It also studies the effect of changing these parameters on load carrying capacity according to both isothermal and thermohydrodynamic approaches.

LENA Conversion Foils Using Single-Layer Graphene, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Our key innovation will be the use of single-layer graphene as LENA conversion foils, with appropriate microgrids and nanogrids to support the foils. Phase I...

21 CFR 189.301 - Tin-coated lead foil capsules for wine bottles.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Tin-coated lead foil capsules for wine bottles. 189... SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SUBSTANCES PROHIBITED FROM USE IN HUMAN FOOD... lead foil capsules for wine bottles. (a) Tin-coated lead foil is composed of a lead foil coated on one...

The new generations of power components will depend on neutron and/or electron bombardment techniques

International Nuclear Information System (INIS)

Lilen, H.

1976-01-01

Neutron and electron bombardment techniques for materials doping, newly introduced in the fabrication of power semiconductor components: diodes, transistors, thyristors, and triacs are briefly outlined. A neutron bombardment of high purity silicon results in a short-lived 31 Si isotope (from 30 Si) decaying into 31 P. The phosphorus with its five peripheral electrons induces a negative doping (N), and the neutron technique gives a homogeneous doping. Furthermore, silicon bombardment with 1 to 2MeV electrons induces micro-ruptures in the lattice, that act as recombination traps reducing carrier lifetimes. Consequently, gold diffusion techniques can be replaced by electron bombardment with a gain in controlling carrier lifetimes [fr

Transient oxidation of Al-deposited Fe-Cr-Al alloy foil

International Nuclear Information System (INIS)

Andoh, A.

1997-01-01

The oxide phases formed on an Al-deposited Fe-Cr-Al alloy foil and an Fe-Cr-Al alloy foil of the same levels of Al and (La+Ce) contents, and their oxidation kinetics have been studied in air at 1173 and 1373 K using TGA, XRD and SEM. Al deposition promotes the growth of metastable aluminas (θ-Al 2 O 3 , γ-Al 2 O 3 ). Scales consisting of θ-Al 2 O 3 and a small amount of α-Al 2 O 3 develop on the Al-deposited foil at 1173 K and exhibit the whisker-type morphology. In the early stage of oxidation at 1373 K, thick scales consisting of θ-Al 2 O 3 and α-Al 2 O 3 grow rapidly on the Al-deposited foil. The transformation from θ-Al 2 O 3 to α-Al 2 O 3 is very fast, and the scales result in only α-Al 2 O 3 . In contrast, α-Al 2 O 3 scales containing a minor amount of FeAl 2 O 4 develop on the alloy foil. The growth rate of α-Al 2 O 3 scales on the Al-deposited foil is smaller than that on the alloy foil and very close to that on NiAl at 1373 K. (orig.)

Annealing of (DU-10Mo)-Zr Co-Rolled Foils

International Nuclear Information System (INIS)

Pacheco, Robin Montoya; Alexander, David John; Mccabe, Rodney James; Clarke, Kester Diederik; Scott, Jeffrey E.; Montalvo, Joel Dwayne; Papin, Pallas; Ansell, George S.

2017-01-01

Producing uranium-10wt% molybdenum (DU-10Mo) foils to clad with Al first requires initial bonding of the DU-10Mo foil to zirconium (Zr) by hot rolling, followed by cold rolling to final thickness. Rolling often produces wavy (DU-10Mo)-Zr foils that should be flattened before further processing, as any distortions could affect the final alignment and bonding of the Al cladding to the Zr co-rolled surface layer; this bonding is achieved by a hot isostatic pressing (HIP) process. Distortions in the (DU-10Mo)-Zr foil may cause the fuel foil to press against the Al cladding and thus create thinner or thicker areas in the Al cladding layer during the HIP cycle. Post machining is difficult and risky at this stage in the process since there is a chance of hitting the DU-10Mo. Therefore, it is very important to establish a process to flatten and remove any waviness. This study was conducted to determine if a simple annealing treatment could flatten wavy foils. Using the same starting material (i.e. DU-10Mo coupons of the same thickness), five different levels of hot rolling and cold rolling, combined with five different annealing treatments, were performed to determine the effect of these processing variables on flatness, bonding of layers, annealing response, microstructure, and hardness. The same final thickness was reached in all cases. Micrographs, textures, and hardness measurements were obtained for the various processing combinations. Based on these results, it was concluded that annealing at 650°C or higher is an effective treatment to appreciably reduce foil waviness.

Annealing of (DU-10Mo)-Zr Co-Rolled Foils

Energy Technology Data Exchange (ETDEWEB)

Pacheco, Robin Montoya [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Alexander, David John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mccabe, Rodney James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Clarke, Kester Diederik [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Scott, Jeffrey E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Montalvo, Joel Dwayne [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Papin, Pallas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ansell, George S. [Colorado School of Mines, Golden, CO (United States)

2017-01-20

Producing uranium-10wt% molybdenum (DU-10Mo) foils to clad with Al first requires initial bonding of the DU-10Mo foil to zirconium (Zr) by hot rolling, followed by cold rolling to final thickness. Rolling often produces wavy (DU-10Mo)-Zr foils that should be flattened before further processing, as any distortions could affect the final alignment and bonding of the Al cladding to the Zr co-rolled surface layer; this bonding is achieved by a hot isostatic pressing (HIP) process. Distortions in the (DU-10Mo)-Zr foil may cause the fuel foil to press against the Al cladding and thus create thinner or thicker areas in the Al cladding layer during the HIP cycle. Post machining is difficult and risky at this stage in the process since there is a chance of hitting the DU-10Mo. Therefore, it is very important to establish a process to flatten and remove any waviness. This study was conducted to determine if a simple annealing treatment could flatten wavy foils. Using the same starting material (i.e. DU-10Mo coupons of the same thickness), five different levels of hot rolling and cold rolling, combined with five different annealing treatments, were performed to determine the effect of these processing variables on flatness, bonding of layers, annealing response, microstructure, and hardness. The same final thickness was reached in all cases. Micrographs, textures, and hardness measurements were obtained for the various processing combinations. Based on these results, it was concluded that annealing at 650°C or higher is an effective treatment to appreciably reduce foil waviness.

Spectra from foil-excited molybdenum ions

International Nuclear Information System (INIS)

Johnson, B.M.; Jones, K.W.; Cecchi, J.L.; Kruse, T.H.

1978-01-01

The extreme-ultraviolet spectra (5 to 55 nm) for foil-excited molybdenum ions have been measured using 22 to 200 MeV beams from the Brookhaven National Laboratory MP tandem Van de Graaff accelerator facility, 20 μg/cm 2 C stripping foils, and a grazing incidence spectrometer. The mean ion charge states (13 to 28) and the narrow distribution widths (about 2 charge states) were accurately predictable from experimental parameters. Where possible, comparisons are given with Mo radiation from tokamaks, vacuum sparks, and laser-excited plasmas

Process for producing molybdenum foil and collapsible tubing

Science.gov (United States)

Bretts, G. R.; Gavert, R. B.; Groschke, G. F.

1971-01-01

Manufacturing process produces molybdenum foil 0.002 cm thick and 305 m long, and forms foil into high-strength, thin-walled tubing which can be flattened for storage on a spool. Desirable metal properties include high thermal conductivity stiffness, yield and tensile stress, and low thermal expansion coeffecient.

Development of a new foil compounded from carbon nanotubes and sputter-deposition carbon

International Nuclear Information System (INIS)

Hiroo Hasebe; Hironori Kuboki; Hiroki Okuno; Isao Yamane; Hiroshi Imao; Nobuhisa Fukunishi; Masayuki Kase; Osamu Kamigaito

2014-01-01

New carbon-nanotube-sputter-deposition-carbon (CNT-SDC) foils were developed and used in the U beam time at the RIKEN RI Beam Factory (RIBF) from October to December 2011. The lifetimes of these new foils were drastically extended, and stable, high-intensity U beams were successfully provided to users. The lifetime of the CNT-SDC foils was 2-5 C, which was 100 times longer than those of static C-foils previously used. The qualitative analysis of the CNT-SDC foils clearly showed that the CNT structure and bundles were broken by beam irradiation. In addition, it was found that CNT bundles in the CNT-SDC foil were grown after the carbon deposition procedure. This structure was considered to be the reason that the CNT-SDC foils maintain advantages of both CNT and SDC foils. (author)

Decontamination with pasty pickling agents forming a strippable foil

International Nuclear Information System (INIS)

Weichselgartner, H.

1991-01-01

This paper describes the development of an in-situ decontamination procedure by applying onto the contaminated surface (in an one-step or multi-step process) pasty, chemically aggressive agents causing dilution and adsorption of the contaminant and then hardening to form a strippable foil. The use of such a foil will result in following advantages, with respect to usual techniques: - sensibly shorter operation duration resulting in lower personnel doses; - reduction of the arising secondary waste volume because there is no need for washing; the volume of the spent strippable foil is much smaller than currently used water volumes; - optimal conditioning of the radioactive waste due to its fixation in a solid (foil); - an accidental contamination in a controlled area can easily be fixed and covered avoiding its propagation

Bombardment of gas molecules on single graphene layer at high temperature

Energy Technology Data Exchange (ETDEWEB)

Murugesan, Ramki [School of Mechanical and Aerospace Engineering, Gyeongsang National University, Jinju, Gyeongnam 660-701 (Korea, Republic of); Park, Jae Hyun [Department of Aerospace and System Engineering and Research Center for Aircraft Parts Technology, Gyeongsang National University, Jinju, Gyeongnam 660-701 (Korea, Republic of); Ha, Dong Sung [Future Propulsion Center, Agency for Defense Development, Daejeon 305-600 (Korea, Republic of)

2014-12-09

Graphite is widely used as a material for rocket-nozzle inserts due to its excellent thermo-physical properties as well as low density. During the operation of rockets, the surface of the graphite nozzle is subjected to very high heat fluxes and the undesirable erosion of the surface occurs due to the bombardment of gas molecules with high kinetic energy, which causes a significant reduction of nozzle performance. However, the understanding and quantification of such bombardment is not satisfactory due to its complexity: The bond breaking-forming happens simultaneously for the carbon atoms of graphene, some gas molecules penetrate through the surface, some of them are reflected from the surface, etc. In the present study, we perform extensive molecular dynamics (MD) simulations to examine the bombardment phenomena in high temperature environment (several thousand Kelvin). Advanced from the previous studies that have focused on the bombardment by light molecules (e.g., H{sub 2}), we will concentrate on the impact by realistic molecules (e.g., CO{sub 2} and H{sub 2}O). LAMMPS is employed for the MD simulations with NVE ensemble and AIREBO potential for graphene. The molecular understanding of the interaction between graphene and highly energetic gas molecules will enable us to design an efficient thermo-mechanical protection system.

Measurements of laser generated soft X-ray emission from irradiated gold foils

Energy Technology Data Exchange (ETDEWEB)

Davis, J. S.; Keiter, P. A.; Klein, S. R.; Drake, R. P.; Shvarts, D. [University of Michigan, 2455 Hayward St., Ann Arbor, Michigan 48109 (United States); Frank, Y.; Raicher, E.; Fraenkel, M. [Soreq Nuclear Research Center, Yavne (Israel)

2016-11-15

Soft x-ray emission from laser irradiated gold foils was measured at the Omega-60 laser system using the Dante photodiode array. The foils were heated with 2 kJ, 6 ns laser pulses and foil thicknesses were varied between 0.5, 1.0, and 2.0 μm. Initial Dante analysis indicates peak emission temperatures of roughly 100 eV and 80 eV for the 0.5 μm and 1.0 μm thick foils, respectively, with little measurable emission from the 2.0 μm foils.

Mechanisms of ion-bombardment-induced DNA transfer into bacterial E. coli cells

Energy Technology Data Exchange (ETDEWEB)

Yu, L.D., E-mail: yuld@thep-center.org [Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Sangwijit, K. [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Prakrajang, K. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Faculty of Science, Maejo University, Chiang Mai 50290 (Thailand); Phanchaisri, B. [Institute of Science and Technology Research, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongkumkoon, P. [Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thopan, P. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Singkarat, S. [Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Anuntalabhochai, S. [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

2014-05-01

Highlights: • Ion bombardment could induce DNA transfer into E. coli cells. • The DNA transfer induction depended on ion energy and fluence. • The mechanism was associated with the bacterial cell envelope structure. • A mechanism phase diagram was proposed to summarize the mechanism. - Abstract: As a useful ion beam biotechnology, ion-bombardment-induced DNA transfer into bacterial Escherichia coli (E. coli) cells has been successfully operated using argon ions. In the process ion bombardment of the bacterial cells modifies the cell envelope materials to favor the exogenous DNA molecules to pass through the envelope to enter the cell. The occurrence of the DNA transfer induction was found ion energy and fluence dependent in a complex manner. At ion energy of a few keV and a few tens of keV to moderate fluences the DNA transfer could be induced by ion bombardment of the bacterial cells, while at the same ion energy but to high fluences DNA transfer could not be induced. On the other hand, when the ion energy was medium, about 10–20 keV, the DNA transfer could not be induced by ion bombardment of the cells. The complexity of the experimental results indicated a complex mechanism which should be related to the complex structure of the bacterial E. coli cell envelope. A phase diagram was proposed to interpret different mechanisms involved as functions of the ion energy and fluence.

Mechanisms of ion-bombardment-induced DNA transfer into bacterial E. coli cells

International Nuclear Information System (INIS)

Yu, L.D.; Sangwijit, K.; Prakrajang, K.; Phanchaisri, B.; Thongkumkoon, P.; Thopan, P.; Singkarat, S.; Anuntalabhochai, S.

2014-01-01

Highlights: • Ion bombardment could induce DNA transfer into E. coli cells. • The DNA transfer induction depended on ion energy and fluence. • The mechanism was associated with the bacterial cell envelope structure. • A mechanism phase diagram was proposed to summarize the mechanism. - Abstract: As a useful ion beam biotechnology, ion-bombardment-induced DNA transfer into bacterial Escherichia coli (E. coli) cells has been successfully operated using argon ions. In the process ion bombardment of the bacterial cells modifies the cell envelope materials to favor the exogenous DNA molecules to pass through the envelope to enter the cell. The occurrence of the DNA transfer induction was found ion energy and fluence dependent in a complex manner. At ion energy of a few keV and a few tens of keV to moderate fluences the DNA transfer could be induced by ion bombardment of the bacterial cells, while at the same ion energy but to high fluences DNA transfer could not be induced. On the other hand, when the ion energy was medium, about 10–20 keV, the DNA transfer could not be induced by ion bombardment of the cells. The complexity of the experimental results indicated a complex mechanism which should be related to the complex structure of the bacterial E. coli cell envelope. A phase diagram was proposed to interpret different mechanisms involved as functions of the ion energy and fluence

Kinetics of interaction from low-energy-ion bombardment of surfaces

International Nuclear Information System (INIS)

Horton, C.C.

1988-01-01

The kinetics of interaction from low energy oxygen ion bombardment of carbon and Teflon surfaces have been investigated. The surfaces were bombarded with 4.5 to 93 eV oxygen ions and emitted species were observed with a mass spectrometer. To obtain the kinetic information, the ion beam was square pulse modulated and reaction products were observed as a function of time. The kinetic information is contained in the response of the emitted species to the pulsed ion beam. Oxygen bombardment of carbon produced CO in three parallel branches with each following an adsorption-desorption process. The fast branch, with a rate constants of 12,000/sec, appeared to be sputter induced an was absent below about 19 eV. The medium and slow branches, with rate constants of 850/sec and 45/sec respectively, has little energy dependence and appeared to be due to chemical sputtering from two sites. The ratio of the fraction of the medium branch to that of the slow was constant at 1:3. The bombardment of Teflon produced CF in two parallel branches, with one following a series process and the other an adsorb-desorb process. The rate constant of the other branch were 22,000/sec and 7,000/sec and the rate constant of the other branch was 90/sec. The total signal fell monotonically with decreasing ion energy with the fraction for each branch holding constant at 71% for the series and 29% for the adsorb-desorb

Effects of hyperthermal proton bombardment on alkanethiol self-assembled monolayer on Au(1 1 1)

Energy Technology Data Exchange (ETDEWEB)

Xi Luan [Surface Science Western, University of Western Ontario, London, Ontario N6A 5B7 (Canada); Zheng Zhi; Lam, N.-S. [Department of Physics, Chinese University of Hong Kong, Shatin, Hong Kong (China); Grizzi, Oscar [Centro Atomico Bariloche, 8400 San Carlos de Bariloche, Rio Negro (Argentina); Lau, W.-M. [Surface Science Western, University of Western Ontario, London, Ontario N6A 5B7 (Canada)], E-mail: llau22@uwo.ca

2007-10-31

The effects of hyperthermal proton bombardment on alkanethiol self-assembled monolayer (SAM) on Au(1 1 1) are studied with scanning tunneling microscopy (STM) and X-ray photoemission spectroscopy (XPS). The STM and XPS results show that proton bombardment with proton energy as low as 2 eV can induce cross-linking of the adsorbed alkanethiols and transform the original ordered SAM lattice to an array of nanoclusters of the cross-linked alkanethiols. For a bombardment at 3 eV with a fluence of 3x10{sup 15} cm{sup -2}, the typical cluster size is about 5 nm. In addition, the cluster size distribution is narrow, with no cluster larger than 8 nm. The cluster growth can be promoted by increasing the fluence at a fixed bombardment energy or increasing the energy at a fixed fluence. This indicates that surface diffusion of alkanethiols and cluster growth can be harnessed by the control of the bombardment energy and fluence.

Effects of hyperthermal proton bombardment on alkanethiol self-assembled monolayer on Au(1 1 1)

International Nuclear Information System (INIS)

Xi Luan; Zheng Zhi; Lam, N.-S.; Grizzi, Oscar; Lau, W.-M.

2007-01-01

The effects of hyperthermal proton bombardment on alkanethiol self-assembled monolayer (SAM) on Au(1 1 1) are studied with scanning tunneling microscopy (STM) and X-ray photoemission spectroscopy (XPS). The STM and XPS results show that proton bombardment with proton energy as low as 2 eV can induce cross-linking of the adsorbed alkanethiols and transform the original ordered SAM lattice to an array of nanoclusters of the cross-linked alkanethiols. For a bombardment at 3 eV with a fluence of 3x10 15 cm -2 , the typical cluster size is about 5 nm. In addition, the cluster size distribution is narrow, with no cluster larger than 8 nm. The cluster growth can be promoted by increasing the fluence at a fixed bombardment energy or increasing the energy at a fixed fluence. This indicates that surface diffusion of alkanethiols and cluster growth can be harnessed by the control of the bombardment energy and fluence

A new method for making long-lived carbon stripper foils

International Nuclear Information System (INIS)

Sugai, Isao; Ishii, Sabro; Hattori, Toshiyuki; Muto, Hideshi; Takahashi, Yohsuke; Kato, Hajime; Yamazaki, Kuniaki.

1989-01-01

We have developed a new method for preparation of long-lived carbon stripper foils, based on the modification of our 'controlled DC arc-discharge method'. The carbon foils consist of multi-layers, and carbon particles in each layer are emitted from the electrode in AC arc-discharge or from the cathode electrode in DC arc-discharge. The lifetimes of the carbon foils made by the new method are equal to or longer than those prepared by the controlled DC arc-discharge method. The new method is simple and powerful to make long-lived carbon stripper foils with higher reliability and reproducibility than the previous method. (author)

Optimization of electron beam crosslinking of wire and cable insulation

International Nuclear Information System (INIS)

Zimek, Zbigniew; Przybytniak, Grażyna; Nowicki, Andrzej

2012-01-01

The computer simulations based on Monte Carlo (MC) method and the ModeCEB software were carried out in connection with electron beam (EB) radiation set-up for crosslinking of electric wire and cable insulation. The theoretical predictions for absorbed dose distribution in irradiated electric insulation induced by scanned EB were compared to the experimental results of irradiation that was carried out in the experimental set-up based on ILU 6 electron accelerator with electron energy 0.5–2.0 MeV. The computer simulation of the dose distributions in two-sided irradiation system by a scanned electron beam in multilayer circular objects was performed for various process parameters, namely electric wire and cable geometry (thickness of insulation layers and copper wire diameter), type of polymer insulation, electron energy, energy spread and geometry of electron beam, electric wire and cable layout in irradiation zone. The geometry of electron beam distribution in the irradiation zone was measured using CTA and PVC foil dosimeters for available electron energy range. The temperature rise of the irradiated electric wire and irradiation homogeneity were evaluated for different experimental conditions to optimize technological process parameters. The results of computer simulation are consistent with the experimental data of dose distribution evaluated by gel-fraction measurements. Such conformity indicates that ModeCEB computer simulation is reliable and sufficient for optimization absorbed dose distribution in the multi-layer circular objects irradiated with scanned electron beams. - Highlights: ► We model wire and cables irradiation process by Monte Carlo simulations. ► We optimize irradiation configuration for various process parameters. ► Temperature rise and irradiation homogeneity were evaluated. ► Calculation (dose) and experimental (gel-fraction) results were compared. ► Computer simulation was found reliable and sufficient for process optimization.

Impact of Ion Bombardment on the Structure and Magnetic Properties of Fe78Si13B9 Amorphous Alloy

Science.gov (United States)

Wu, Yingwei; Peng, Kun

2018-06-01

Amorphous Fe78Si13B9 alloy ribbons were bombarded by ion beams with different incident angles ( θ ). The evolution of the microstructure and magnetic properties of ribbons caused by ion beam bombardment was investigated by x-ray diffraction, transmission electron microscope and vibrating sample magnetometer analysis. Low-incident-angle bombardment led to atomic migration in the short range, and high-incident-angle bombardment resulted in the crystallization of amorphous alloys. Ion bombardment induces magnetic anisotropy and affects magnetic properties. The effective magnetic anisotropy was determined by applying the law of approach to saturation, and it increased with the increase of the ion bombardment angle. The introduction of effective magnetic anisotropy will reduce the permeability and increase the relaxation frequency. Excellent high-frequency magnetic properties can be obtained by selecting suitable ion bombardment parameters.

Examination of the picture properties of luminescence memory foils

International Nuclear Information System (INIS)

Ewert, U.; Heine, S.; Nockemann, C.; Stade, J.; Tillack, G.R.; Wessel, H.; Zscherpel, U.; Mattis, A.

1995-01-01

Luminescence memory foils are a new medium for radiography without films. They are known by the name of image plates or digital memory foils. The suitability of such systems for industrial radiography is examined. (orig.) [de

Penetration of Hydrogen clusters from 10 to 120 kev/u in carbon foils. Study of their slowing-down and charge distribution of emerging fragments

International Nuclear Information System (INIS)

Ray, E.M.

1991-06-01

This work is devoted to the experimental study of the interaction between fast (10 to 120 keV/p) hydrogen clusters with thin solid targets. First, we have studied the slowing-down of H n + (2≤n≤21) clusters through carbon foils. Up to date this had been made only with molecular ions. We obtain evidence for vicinage effects on the energy loss of proton-clusters. We show that for projectile energies larger than 50 keV/p, the energy loss of a proton in a cluster is enhanced when compared to that of an isolated proton of the same velocity. At lower incident energies, it is a decrease of the energy loss which is observed. The same effect is also observed in the energy lost in the entrance window of a surface barrier detector bombarded by clusters. This phenomenon is interpreted in terms of interferences between individual polarisation wakes induced by each proton of the cluster. In the second part, we propose an accurate method to study the charge state of the atomic fragments resulting from the dissociation of fast H n + (2≤n≤15) clusters through a carbon foil. This method gives also the distribution of the neutral atoms among the emerging fragments. These distributions are finally compared with binomial laws expected from independent particles

High dose He/sup +/ bombardment of niobium at 800/sup 0/ to 1400/sup 0/C

Energy Technology Data Exchange (ETDEWEB)

Biersack, J P [Hahn-Meitner-Institut fuer Kernforschung Berlin G.m.b.H. (Germany, F.R.)

1976-12-01

In proposed fusion reactors, the first wall will be bombarded by low energy D/sup +/, T/sup +/ and He/sup +/ ions to very high doses. Room temperature irradiations with 9 keV He/sup +/ (Roth et al. 1975) showed an initial phase of blistering between 0.05 and 0.25 C/cm/sup 2/, and a final state of considerable surface roughness at 8 to 112 C/cm/sup 2/(7 x 10/sup 20/He/sup +//cm/sup 2/). The present irradiation experiments with 6 keV He/sup +/ are carried out with polycrystalline Nb foils at temperatures between 800 and 1400/sup 0/C in order to study the influence of He mobility and of Nb surface diffusion during irradiation. The applied doses range from 2.5 x 10/sup 17/He/sup +//cm/sup 2/ (blistering) to 5 x 10/sup 20/He/sup +//cm/sup 2/ which corresponds to at least several weeks of reactor operation. The resulting changes of the niobium surface structures are observed by scanning electron microscopy and are pictorially presented in this paper. Mainly, sponge-like open structures are seen to develop at high doses, with increasing physical dimensions at higher temperatures.

A state enumeration of the foil knot

OpenAIRE

Ramaharo, Franck; Rakotondrajao, Fanja

2017-01-01

We split the crossings of the foil knot and enumerate the resulting states with a generating polynomial. Unexpectedly, the number of such states which consist of two components are given by the lazy caterer's sequence. This sequence describes the maximum number of planar regions that is obtained with a given number of straight lines. We then establish a bijection between this partition of the plane and the concerned foil splits sequence.

An Experimental Study on Micro Clinching of Metal Foils with Cutting by Laser Shock Forming.

Science.gov (United States)

Wang, Xiao; Li, Cong; Ma, Youjuan; Shen, Zongbao; Sun, Xianqing; Sha, Chaofei; Gao, Shuai; Li, Liyin; Liu, Huixia

2016-07-13

This paper describes a novel technique for joining similar and dissimilar metal foils, namely micro clinching with cutting by laser shock forming. A series of experiments were conducted to study the deformation behavior of single layer material, during which many important process parameters were determined. The process window of the 1060 pure aluminum foils and annealed copper foils produced by micro clinching with cutting was analyzed. Moreover, similar material combination (annealed copper foils) and dissimilar material combination (1060 pure aluminum foils and 304 stainless steel foils) were successfully achieved. The effect of laser energy on the interlock and minimum thickness of upper foils was investigated. In addition, the mechanical strength of different material combinations joined by micro clinching with cutting was measured in single lap shearing tests. According to the achieved results, this novel technique is more suitable for material combinations where the upper foil is thicker than lower foil. With the increase of laser energy, the interlock increased while the minimum thickness of upper foil decreased gradually. The shear strength of 1060 pure aluminum foils and 304 stainless steel foils combination was three times as large as that of 1060 pure aluminum foils and annealed copper foils combination.

ANALYTICAL MODELING OF ELECTRON BACK-BOMBARDMENT INDUCED CURRENT INCREASE IN UN-GATED THERMIONIC CATHODE RF GUNS

Energy Technology Data Exchange (ETDEWEB)

Edelen, J. P. [Fermilab; Sun, Y. [Argonne; Harris, J. R. [AFRL, NM; Lewellen, J. W. [Los Alamos Natl. Lab.

2016-09-28

In this paper we derive analytical expressions for the output current of an un-gated thermionic cathode RF gun in the presence of back-bombardment heating. We provide a brief overview of back-bombardment theory and discuss comparisons between the analytical back-bombardment predictions and simulation models. We then derive an expression for the output current as a function of the RF repetition rate and discuss relationships between back-bombardment, fieldenhancement, and output current. We discuss in detail the relevant approximations and then provide predictions about how the output current should vary as a function of repetition rate for some given system configurations.

Production and thickness determination of thin plastic scintillator foils

International Nuclear Information System (INIS)

Xiao, B.; Lee, S.; Hagel, K.; Haddad, F.; Li, J.; Lou, Y.; Mdeiwayeh, N.; Tezkratt, R.; Wada, R.; Utley, D.; Natowitz, J.B.

1995-01-01

A method of making large thin plastic scintillator foils with good uniformity is presented. The use of Fourier Transform Infrared Spectroscopy (FTIR) to test the foil uniformity and to establish an empirical thickness calibration curve is described. ((orig.))

Selecting foils for identification lineups: matching suspects or descriptions?

Science.gov (United States)

Tunnicliff, J L; Clark, S E

2000-04-01

Two experiments directly compare two methods of selecting foils for identification lineups. The suspect-matched method selects foils based on their match to the suspect, whereas the description-matched method selects foils based on their match to the witness's description of the perpetrator. Theoretical analyses and previous results predict an advantage for description-matched lineups both in terms of correctly identifying the perpetrator and minimizing false identification of innocent suspects. The advantage for description-matched lineups should be particularly pronounced if the foils selected in suspect-matched lineups are too similar to the suspect. In Experiment 1, the lineups were created by trained police officers, and in Experiment 2, the lineups were constructed by undergraduate college students. The results of both experiments showed higher suspect-to-foil similarity for suspect-matched lineups than for description-matched lineups. However, neither experiment showed a difference in correct or false identification rates. Both experiments did, however, show that there may be an advantage for suspect-matched lineups in terms of no-pick and rejection responses. From these results, the endorsement of one method over the other seems premature.

UV Ink-Jet printability and durability of stone and foil

Directory of Open Access Journals (Sweden)

Tadeja Muck

2014-07-01

Full Text Available he use of ultraviolet (UV printing technology has impacted printing industry in last years due to its applicability on many different »absorptive« as well as »non-absorptive« printing materials. The printability of building materials and recycled foils is relatively unknown. For primary building materials like stones, functionality can be explored with the use of UV printing technology; increased visual, informative effect or even “creative printing” of buildings. Also several aspects of recycled foils reusability as a printing material could be find (printed packaging material or also like secondary building materials. In the present study, printability of the stone and recycled foil and durability of UV prints was explored by means of macroscopically and microscopically characterization. Results indicate that higher print quality can be achieved on polished stone and on coated foil, which surfaces have higher smoothness. Durability of UV prints at freezing is higher at unpolished stone and coated foil that is at materials with the higher surface energy.

Composite Design for a Foiling Optimist Dinghy

Directory of Open Access Journals (Sweden)

Carolyn Oddy

2018-02-01

Full Text Available In April 2017, a foiling Optimist dingy designed entirely by students, was successfully tested under standard sailing conditions in the waters outside Gothenburg. In order to achieve take of wind speeds as low as 6 m/s, a stiff and lightweight design of the dinghy and its foiling components was necessary. There have been few successful attempts to make an Optimist foil in a stable manner, as such there were no standards or recommendations available for the design. Therefore, a simulation driven structural design methodology for hydrofoils, centreboards, centreboard-to-hull connections, and necessary hull reinforcements using sandwich structures was adopted. The proposed design was then manufactured, allowing for a significantly stiffer hull and a 20% decrease in weight over a conventional Optimist. Excluding the rig and sail, the final weight came to 27 kg.

Dynamic environmental control mechanisms for pneumatic foil constructions

Science.gov (United States)

Flor, Jan-Frederik; Wu, Yupeng; Beccarelli, Paolo; Chilton, John

2017-11-01

Membrane and foil structures have become over the last decades an attractive alternative to conventional materials and building systems with increasing implementation in different typologies and scale. The development of transparent, light, flexible and resistant materials like Ethylene Tetrafluoroethylene (ETFE) has triggered a rethinking of the building envelope in the building industry towards lightweight systems. ETFE foil cushions have proven to fulfil the design requirements in terms of structural efficiency and aesthetic values. But the strategies to satisfy increasing demands of energy efficiency and comfort conditions are still under development. The prediction and manipulation of the thermo-optical behaviour of ETFE foil cushion structures currently remain as one of the main challenges for designers and manufacturers. This paper reviews ongoing research regarding the control of the thermo-optical performance of ETFE cushion structures and highlights challenges and possible improvements. An overview of different dynamic and responsive environmental control mechanisms for multilayer foil constructions is provided and the state of the art in building application outlined by the discussion of case studies.

Material Properties of Laser-Welded Thin Silicon Foils

Directory of Open Access Journals (Sweden)

M. T. Hessmann

2013-01-01

Full Text Available An extended monocrystalline silicon base foil offers a great opportunity to combine low-cost production with high efficiency silicon solar cells on a large scale. By overcoming the area restriction of ingot-based monocrystalline silicon wafer production, costs could be decreased to thin film solar cell range. The extended monocrystalline silicon base foil consists of several individual thin silicon wafers which are welded together. A comparison of three different approaches to weld 50 μm thin silicon foils is investigated here: (1 laser spot welding with low constant feed speed, (2 laser line welding, and (3 keyhole welding. Cross-sections are prepared and analyzed by electron backscatter diffraction (EBSD to reveal changes in the crystal structure at the welding side after laser irradiation. The treatment leads to the appearance of new grains and boundaries. The induced internal stress, using the three different laser welding processes, was investigated by micro-Raman analysis. We conclude that the keyhole welding process is the most favorable to produce thin silicon foils.

An Experimental Study on Micro Clinching of Metal Foils with Cutting by Laser Shock Forming

Directory of Open Access Journals (Sweden)

Xiao Wang

2016-07-01

Full Text Available This paper describes a novel technique for joining similar and dissimilar metal foils, namely micro clinching with cutting by laser shock forming. A series of experiments were conducted to study the deformation behavior of single layer material, during which many important process parameters were determined. The process window of the 1060 pure aluminum foils and annealed copper foils produced by micro clinching with cutting was analyzed. Moreover, similar material combination (annealed copper foils and dissimilar material combination (1060 pure aluminum foils and 304 stainless steel foils were successfully achieved. The effect of laser energy on the interlock and minimum thickness of upper foils was investigated. In addition, the mechanical strength of different material combinations joined by micro clinching with cutting was measured in single lap shearing tests. According to the achieved results, this novel technique is more suitable for material combinations where the upper foil is thicker than lower foil. With the increase of laser energy, the interlock increased while the minimum thickness of upper foil decreased gradually. The shear strength of 1060 pure aluminum foils and 304 stainless steel foils combination was three times as large as that of 1060 pure aluminum foils and annealed copper foils combination.

Improvements of High Current/ Low Pressure Liquid And Gas Targets For Cyclotron Produced Radioisotopes

Energy Technology Data Exchange (ETDEWEB)

Hur, M. G. [Korea Atomic Energy Research Institute, Jeongup (Korea, Republic of); Hong, B. H. [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Chai, J. S. [SungKyunKwan University, Seoul (Korea, Republic of)

2009-07-01

The development of the C-11 cylindrical target with cooling fin for 13 MeV and 30 MeV proton beams and the development of pleated double-foil O-18 water target were carried out. For the test of new target system it was done at 2 pilots of cyclotron centres in Korea. The development of pleated double-foil O-18 water target was also executed. The pleated foil has the more advantages than flat foil. With the same beam bombarding the pleated foil with cooling had more yield of F-18production. CFD and FEM study were considered to design of the pleated foil and flat foil structure. (author)

Ion bombardment damage in a modified Fe-9Cr-1Mo steel

International Nuclear Information System (INIS)

Farrell, K.; Lee, E.H.

1984-01-01

A normalized-and-tempered Fe-9Cr-1Mo steel, with small Nb and V additions, was bombarded with 4-MeV iron ions to 100 dpa at 400, 450, 500, 550, and 600 0 C. Major damage feature was dislocation tangles which coarsened with increasing bombardment temperature. Sparse cavities were heterogeneously distributed at 500 and 550 0 C. Incorporation of helium and deuterium simultaneously in the bombardments at rates of 10 and 45 appM/dpa, respectively, introduced very high concentrations of small cavities at all temperatures, many of them on grain boundaries. These cavities were shown to be promoted by helium. A small fraction of the matrix cavities exhibited bias-driven growth at 500 and 550 0 C, with swelling 0 C higher than the peak swelling temperature found in neutron irradiations, which is compatible with the higher damage rate used in the ion bombardments. High concentrations of subgrain boundaries and dislocations resulting from the heat treatment, and unbalanced cavity and dislocation sink strengths in the damage structures contribute to the swelling resistance. Such resistance may not be permanent. High densities of bubbles on grain boundaries indicate a need for helium embrittlement tests

Hydrogen pumping and release by graphite under high flux plasma bombardment

International Nuclear Information System (INIS)

Hirooka, Y.; Leung, W.K.; Conn, R.W.; Goebel, D.M.; LaBombard, B.; Nygren, R.; Wilson, K.L.

1988-01-01

Inert gas (helium or argon) plasma bombardment has been found to increase the surface gas adsorptivity of isotropic graphite (POCO-graphite), which can then getter residual gases in a high vacuum system. The inert gas plasma bombardment was carried out at a flux ≅ 1 x 10 18 ions s -1 cm -2 to a fluence of the order of 10 21 ions/cm 2 and at temperatures around 800 0 C. The gettering capability of graphite can be easily recovered by repeating inert gas plasma bombardment. The activated graphite surface exhibits a smooth, sponge-like morphology with significantly increased pore openings, which correlates with the observed increase in the surface gas adsorptivity. The activated graphite surface has been observed to pump hydrogen plasma particles as well. From calibrated H-alpha measurements, the dynamic hydrogen retention capacity is evaluated to be as large as 2 x 10 18 H/cm 2 at temperatures below 100 0 C and at a plasma bombarding energy of 300 eV. The graphite temperature was varied between 15 and 480 0 C. Due to the plasma particle pumping capability, hydrogen recycling from the activated graphite surface is significantly reduced, relative to that from a pre-saturated surface. A pre-saturated surface was also observed to reproducibly pump a hydrogen plasma to a concentration of 9.5 x 10 17 H/cm 2 . The hydrogen retention capacity of graphite is found to decrease with increasing temperature. A transient pumping mechanism associated with the sponge-like surface morphology is conjectured to explain the large hydrogen retention capacity. Hydrogen release behavior under helium and argon plasma bombardment was also investigated, and the result indicated the possibility of some in-pore retrapping effect. 43 refs., 11 figs

Practical and research aspects of beam-foil spectroscopy

International Nuclear Information System (INIS)

Bashkin, S.

1974-01-01

Practical aspects of the application of low-energy accelerators to research in beam-foil spectroscopy are discussed, and the kinds of equipment and associated costs are described in some detail. Some typical beam-foil experiments, emphasizing the most recent studies, are treated so as to show how relatively simple facilities can be used to produce physics of great interest

Stable transformation via particle bombardment in two different soybean regeneration systems.

Science.gov (United States)

Sato, S; Newell, C; Kolacz, K; Tredo, L; Finer, J; Hinchee, M

1993-05-01

The Biolistics(®) particle delivery system for the transformation of soybean (Glycine max L. Merr.) was evaluated in two different regeneration systems. The first system was multiple shoot proliferation from shoot tips obtained from immature zygotic embryos of the cultivar Williams 82, and the second was somatic embryogenesis from a long term proliferative suspension culture of the cultivar Fayette. Bombardment of shoot tips with tungsten particles, coated with precipitated DNA containing the gene for β-glucuronidase (GUS), produced GUS-positive sectors in 30% of the regenerated shoots. However, none of the regenerants which developed into plants continued to produce GUS positive tissue. Bombardment of embryogenic suspension cultures produced GUS positive globular somatic embryos which proliferated into GUS positive somatic embryos and plants. An average of 4 independent transgenic lines were generated per bombarded flask of an embryogenic suspension. Particle bombardment delivered particles into the first two cell layers of either shoot tips or somatic embryos. Histological analysis indicated that shoot organogenesis appeared to involve more than the first two superficial cell layers of a shoot tip, while somatic embryo proliferation occurred from the first cell layer of existing somatic embryos. The different transformation results obtained with these two systems appeared to be directly related to differences in the cell types which were responsible for regeneration and their accessibility to particle penetration.

PENGEMBANGAN FOIL NACA SERI 2412 SEBAGAI SISTEM PENYELAMAN MODEL KAPAL SELAM

Directory of Open Access Journals (Sweden)

Ali Munazid

2015-06-01

Full Text Available Bentuk  foil menghasilkan gaya angkat (lift force ketika foil dilewati oleh aliran fluida  karena adanya pengaruh interaksi antara aliran fluida dengan permukaan foil yang mengakibatkan tekanan permukaan atas lebih kecil dari permukaan bawah. Bagaimana mengaplikasikan teori foil pada hydroplane kapal selam sebagai  system penyelaman, dengan membalik foil maka lift force tersebut menjadi gaya ke bawah, dengan demikian memungkinkan kapal selam dapat menyelam, melayang dan bermanouver di bawah air, seperti halnya gerak pesawat terbang yang terbang dan melayang dengan menggunakan sayap. Dilakukan penelitian dan pengamatan terhadap kemampuan penyelaman (diving plan dari foil NACA seri 2412 pada model kapal selam, dengan mencari nilai Cl (coefisien lift di Laboratorium, serta mendesain bentuk badan kapal selam dan analisa gaya-gaya yang bekerja pada model kapal selam, jumlah gaya-gaya yang bekerja keatas lebih rendah dari gaya-gaya ke bawah maka kapal selam mampu menyelam. Penerapan Hydroplane sebagai diving plane dapat diterapkan, kemampuan penyelaman dipengaruhi oleh sudut flip  Hydroplane dan kecepatan model, semakin besar kecepatan dan sudut flip maka semakin besar kedalaman penyelaman yang dapat dilakukan.

Rapid growth of single-layer graphene on the insulating substrates by thermal CVD

Energy Technology Data Exchange (ETDEWEB)

Chen, C.Y. [Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093 (China); Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Dai, D.; Chen, G.X.; Yu, J.H. [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Nishimura, K. [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Advanced Nano-processing Engineering Lab, Mechanical Systems Engineering, Kogakuin University (Japan); Lin, C.-T. [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Jiang, N., E-mail: jiangnan@nimte.ac.cn [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Zhan, Z.L., E-mail: zl_zhan@sohu.com [Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093 (China)

2015-08-15

Highlights: • A rapid thermal CVD process has been developed to directly grow graphene on the insulating substrates. • The treating time consumed is ≈25% compared to conventional CVD procedure. • Single-layer and few-layer graphene can be formed on quartz and SiO{sub 2}/Si substrates, respectively. • The formation of thinner graphene at the interface is due to the fast precipitation rate of carbon atoms during cooling. - Abstract: The advance of CVD technique to directly grow graphene on the insulating substrates is particularly significant for further device fabrication. As graphene is catalytically grown on metal foils, the degradation of the sample properties is unavoidable during transfer of graphene on the dielectric layer. Moreover, shortening the treatment time as possible, while achieving single-layer growth of graphene, is worthy to be investigated for promoting the efficiency of mass production. Here we performed a rapid heating/cooling process to grow graphene films directly on the insulating substrates by thermal CVD. The treating time consumed is ≈25% compared to conventional CVD procedure. In addition, we found that high-quality, single-layer graphene can be formed on quartz, but on SiO{sub 2}/Si substrate only few-layer graphene can be obtained. The pronounced substrate effect is attributed to the different dewetting behavior of Ni films on the both substrates at 950 °C.

Direct evidence for a thermal effect of Ar+ ion bombardment in a conventional sputtering mode

International Nuclear Information System (INIS)

Okuyama, F.; Fujimoto, Y.

1986-01-01

Evidence is presented that the Ar + ion bombardment for sputtering in Auger electron spectroscopy can heat the target up to 2000 0 C if the target has poor heat conduction. Polycrystalline microneedles of Cr exhibited spherical tips after being exposed to 3 keV Ar + ions, proving that the needle tips were melted by impacting Ar + ions. Microneedles of Mo ion bombarded under the same condition were bent plastically, which perhaps reflects the thermal annealing of the needles during ion bombardment

Miniature electron bombardment evaporation source: evaporation rate measurement

International Nuclear Information System (INIS)

Nehasil, V.; Masek, K.; Matolin, V.; Moreau, O.

1997-01-01

Miniature electron beam evaporation sources which operate on the principle of vaporization of source material, in the form of a tip, by electron bombardment are produced by several companies specialized in UHV equipment. These sources are used primarily for materials that are normally difficult to deposit due to their high evaporation temperature. They are appropriate for special applications such as heteroepitaxial thin film growth requiring a very low and well controlled deposition rate. A simple and easily applicable method of evaporation rate control is proposed. The method is based on the measurement of ion current produced by electron bombardment of evaporated atoms. The absolute evaporation flux values were measured by means of the Bayard-Alpert ion gauge, which enabled the ion current vs evaporation flux calibration curves to be plotted. (author). 1 tab., 4 figs., 6 refs

Measurement of excitation yields of low energy prompt γ-ray from proton bombardment of Cr-foils with energies ranging between 1.0 and 3.0 MeV

International Nuclear Information System (INIS)

Goncharov, A.

2014-01-01

The goal of this work is measurement of differential cross sections for the production of 378 keV γ-rays from the reactions 52 Cr(p,γ1) 53 Mn and 53 Cr(p,nγ1) 53 Mn for proton energies ranging between 1.0 and 3.0 MeV at the laboratory angle of 90° using foils with thickness ∼1.9×10 18 at/cm 2 (∼ 0.23 μm) of nat Cr.

Design of large size segmented GEM foils and Drift PCB for CBM MUCH

International Nuclear Information System (INIS)

Saini, J.; Dubey, A.K.; Chattopadhyay, S.

2016-01-01

Triple GEM (Gas Electron Multiplier), sector shaped detectors will be used for Muon tracking in the Compressed Baryonic Matter (CBM) experiment at Anti-proton Ion Research (FAIR) facility at Darmstadt, Germany. The sizes of the detectors modules in the Muon Chambers (MUCH) are of the order of 1 meter with active area of about 75cms. Progressive pad geometry is chosen for the readout from these detectors. In construction of these chambers, three GEM foils are stacked on top of each other in a 3/2/2/2 gap configuration. The GEM foils are double layered copper clad 50μm thin Kapton foil. Each GEM foil has millions of holes on it. Foils of large surface area are prone to damages due to discharges owing to the high capacitance of the foil. Hence, these foils have their top surfaces divided into segments of about 100 sq.cm. Further segmentation may be necessary when there are high rate requirements, as in the case of CBM. For the GEM foils of CBM MUCH, a 24 segment layout has been adopted. Short-circuit in any of the GEM-holes will make entire foil un-usable. To reduce such occurrences, segment to segment isolation using opto-coupler in series with the GEM-foil segments has been introduced. Hence, a novel design for GEM chamber drift-PCB and foils has been made. In this scheme, each segment is powered and controlled individually. At the same time, the design takes into account, the space constraints, not only in x-y plane, but also in the z, due to compact assembly of MUCH detector layers

A study of molecular effects in beam-foil spectroscopy

International Nuclear Information System (INIS)

Andresen, B.; Veje, E.

1979-01-01

Relative populations of ns + nd levels in hydrogen as functions of the principal quantum number n have been measured with beams of H + , H 2 + , and H 3 + impinging on thin carbon foils at 25 keV/amu and 100 keV/amu. Enhancements of 20% and 45% for dimer and trimer clusters are observed uniformly for all levels. A possible explanation in terms of screening of the Coulomb repulsion between the protons inside the foil, thus reducing the effective thickness of the foil, is given. All relative populations closely follow an nsup(P) power law with p = -4.0 and -3.7 at 25 keV/amu and 100 keV/amu, respectively, in perfect analogy with atomic collision experiments. O + /O 2 + -foil excitations at 100 keV and 155 keV show a simular molecular effect, but in reverse with a larger mean charge produced by the dimer. (Auth.)

Effects of stern-foil submerged elevation on the lift and drag of a hydrofoil craft

Science.gov (United States)

Suastika, K.; Apriansyah

2018-03-01

Effects of the stern-foil submerged elevation on the lift and drag of a hydrofoil craft are studied by using computational fluid dynamics (CFD) and by considering three alternative stern-foil submerged elevations. The submerged elevation of the front foil is kept constant in all the alternatives. From among the alternatives, the deepest stern-foil placement results in the highest stern-foil lift with the highest foil’s lift-to-drag ratio. However, considering the lift-to-drag ratio of the whole foil-strut-hull system, the shallowest stern-foil placement results in the highest lift-to-drag ratio. The struts and the foil’s submerged elevation significantly affects the drag of the whole foil-strut-hull system.

Stresses in the foil of an electron accelerator extraction channel

International Nuclear Information System (INIS)

Abroyan, M.A.; Makarenko, T.I.; Tokmakov, I.L.

1983-01-01

Stresses in the foil of an electron accelerator extraction channel are assessed with account of contributions of thermal expansion and stress concentrations during switchings. Optimization of extraction grid parameters of the electron accelerator extraction channel and choice of foil material for high current electron beam is conducted. It is suggested that an extraction grid with circular cells and Al-Mg foil should be used. A simple formula applicable for design calculations is proposed for evaluation of stress concentration coefficient during phase switchings

Materials surface modification by plasma bombardment under simultaneous erosion and redeposition conditions

International Nuclear Information System (INIS)

Hirooka, Y.; Goebel, D.M.; Conn, R.W.

1986-07-01

The first in-depth investigation of surface modification of materials by continuous, high-flux argon plasma bombardment under simultaneous erosion and redeposition conditions have been carried out for copper and 304 stainless steel using the PISCES facility. The plasma bombardment conditions are: incident ion flux range from 10 17 to 10 19 ions sec -1 cm -2 , total ion fluence is controlled between 10 19 and 10 22 ions cm -2 , electron temperature range from 5 to 15 eV, and plasma density range from 10 11 to 10 13 cm -3 . The incident ion energy is 100 eV. The sample temperature is between 300 and 700K. Under redeposition dominated conditions, the material erosion rate due to the plasma bombardment is significantly smaller (by a factor up to 10) than that can be expected from the classical ion beam sputtering yield data. It is found that surface morphologies of redeposited materials strongly depend on the plasma bombardment condition. The effect of impurities on surface morphology is elucidated in detail. First-order modelings are implemented to interpret the reduced erosion rate and the surface evolution. Also, fusion related surface properties of redeposited materials such as hydrogen reemission and plasma driven permeation have been characterized

Effect of the ion bombardment on the apparent barrier height in GaAs Schottky junctions

International Nuclear Information System (INIS)

Horvath, Zs. J.

1994-01-01

The bombardment of the semiconductor with different particles often results in the change of the doping concentration at the semiconductor surface. In this paper the effects of this near-interface concentration change on the apparent and real Schottky barrier heights are discussed. Experimental results obtained in GaAs Schottky junctions prepared on ion-bombarded semiconductor surfaces are analysed, and it is shown that their electrical characteristics are strongly influenced by the near-interface concentration change due to the ion bombardment. (author). 36 refs., 2 figs

Dynamics of laser mass-limited foil interaction at ultra-high laser intensities

Energy Technology Data Exchange (ETDEWEB)

Yu, T. P., E-mail: tongpu@nudt.edu.cn [College of Science, National University of Defense Technology, Changsha 410073 (China); State Key Laboratory of High Performance Computing, National University of Defense Technology, Changsha 410073 (China); Sheng, Z. M. [Key Laboratory for Laser Plasmas (MoE) and Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Yin, Y.; Zhuo, H. B.; Ma, Y. Y.; Shao, F. Q. [College of Science, National University of Defense Technology, Changsha 410073 (China); Pukhov, A. [Institut für Theoretische Physik I, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf (Germany)

2014-05-15

By using three-dimensional particle-in-cell simulations with synchrotron radiation damping incorporated, dynamics of ultra-intense laser driven mass-limited foils is presented. When a circularly polarized laser pulse with a peak intensity of ∼10{sup 22} W/cm{sup 2} irradiates a mass-limited nanofoil, electrons are pushed forward collectively and a strong charge separation field forms which acts as a “light sail” and accelerates the protons. When the laser wing parts overtake the foil from the foil boundaries, electrons do a betatron-like oscillation around the center proton bunch. Under some conditions, betatron-like resonance takes place, resulting in energetic circulating electrons. Finally, bright femto-second x rays are emitted in a small cone. It is also shown that the radiation damping does not alter the foil dynamics radically at considered laser intensities. The effects of the transverse foil size and laser polarization on x-ray emission and foil dynamics are also discussed.

Control of Oscillating Foil for Propulsion of Biorobotic Autonomous Underwater Vehicle (AUV

Directory of Open Access Journals (Sweden)

S. N. Singh

2005-01-01

Full Text Available The paper treats the question of control of a laterally and rotationally oscillating hydrofoil for the propulsion of biologically inspired robotic (biorobotic autonomous underwater vehicles (BAUVs. Sinusoidal oscillations of foils produce maneuvering and propulsive forces. The design is based on the internal model principle. Two springs are used to transmit forces from the actuators to the foil. Oscillating fins produce periodic forces, which can be used for fish-like propulsion and control of autonomous underwater vehicles (AUVs. The equations of motion of the foil include hydrodynamic lift and moment based on linear, unsteady, aerodynamic theory. A control law is derived for the lateral and rotational sinusoidal oscillation of the foil. In the closed-loop system, the lateral displacement and the rotational angle of the foil asymptotically follow sinusoidal trajectories of distinct frequencies and amplitudes independently. Simulation results are presented to show the trajectory tracking performance of the foil for different freestream velocities and sinusoidal command trajectories.

Monolithic exploding foil initiator

Science.gov (United States)

Welle, Eric J; Vianco, Paul T; Headley, Paul S; Jarrell, Jason A; Garrity, J. Emmett; Shelton, Keegan P; Marley, Stephen K

2012-10-23

A monolithic exploding foil initiator (EFI) or slapper detonator and the method for making the monolithic EFI wherein the exploding bridge and the dielectric from which the flyer will be generated are integrated directly onto the header. In some embodiments, the barrel is directly integrated directly onto the header.

Development of pits and cones on ion bombarded copper

International Nuclear Information System (INIS)

Tanovic, L.A.; Carter, G.; Nobes, M.J.; Whitton, I.L.; Williams, J.S.

1980-01-01

The formation of pits and cones on Ar ion bombarded copper has been studied. Carefully polished surfaces of large grained 99.999% pure copper crystals have been bombarded at normal incidence with 40 keV argon ions. The cone formation has been investigated for annealed and non-annealed crystals at room temperature and at 30 K and in the case of monocrystal and polycrystal samples. Although in the most other studies the presence of impurities is as a necessary condition for generation of cones and pits the obtained experimental results show that under certain conditions these features are formed on clean surfaces. It is shown that the dominant parameter in the production of cones on copper is the crystal orientation [ru

Preparation of self-supporting metallic foils of nickel isotopes

International Nuclear Information System (INIS)

Sugai, Isao.

1975-01-01

This is the fourth report on the practical methods of target preparation for use in low energy nuclear experiments following the previous one (INS-J-150). An electroplating method has been developed as a dependable and reproducible technique for making self-supporting metallic foils of nickel in the thickness range of 0.5 to 10 mg/cm 2 . The procedures minimized the necessary amount of material so that nickel isotopes could be processed economically. Impurity contamination of the nickel foils during the electroplating process was less than 500 ppm, and the thickness variation in each foil was less than 3% of the central thickness. (auth.)

Measurement of 107Ag(α,γ)111In cross sections

International Nuclear Information System (INIS)

Baglin, Coral M.; Norman, Eric B.; Larimer, Ruth-Mary; Rech, Gregory A.

2004-01-01

Cross sections have been measured for the 107 Ag(α,γ) 111 In reaction at several α-particle energies between 7.8 MeV and 11.9 MeV. This reaction is of interest because it can provide a check on calculations of low-energy (α,γ) cross sections required for stellar nucleosynthesis predictions. Stacks of natural Ag foils of 1 (micro)m thickness and 99.97% purity were bombarded with 4 He + beams. Following irradiation, the yields of the 171-keV and 245-keV photons produced in the 2.805 day electron-capture decay of the 111 In product nucleus were measured off-line. The Ag foils were interleaved with 99.6% purity, 6 (micro)m thick natural Ti foils so that known cross sections for the 48 Ti(α,n) reaction could be used to check the accuracy of the beam current integration. For any given beam energy, beam energy degradation in the foils resulted in lower effective bombarding energies for successive foils in the stack, enabling measurements to be made for several energies per irradiation. The measured cross sections are compared with published statistical-model calculations

Calculation of electron transmission through aluminium foil

International Nuclear Information System (INIS)

Abroyan, M.A.; Mel'ker, A.I.; Mikhajlin, A.I.; Sirotinkin, V.V.; Tokmakov, I.L.

1987-01-01

Calculated by Monte Carlo method energy and angular distributions of electrons transmitted through aluminium foil with 50 μm thickness are presented. 200-500 electron energy ranges and angles of electron incidence on foil from 0 to 40 deg C are considered. That allows to use results for more universal accelerator group, for example, for accelerators with scanning beam used in industry. The received values of angular and energy characteristics allow to increase essentially estimation accuracy of accelerator extraction devices and dose distribution on irradiating item

Diffusion processes in bombardment-induced surface topography

International Nuclear Information System (INIS)

Robinson, R.S.

1984-01-01

A treatment is given of the problem of surface diffusion processes occurring during surface topography development, whenever a surface is simultaneously seeded with impurities and ion bombarded. The development of controllable topography and the importance of surface diffusion parameters, which can be obtained during these studies, are also analyzed. 101 refs.; 7 figs.; 2 tabs

Computer simulation of the topography evolution on ion bombarded surfaces

CERN Document Server

Zier, M

2003-01-01

The development of roughness on ion bombarded surfaces (facets, ripples) on single crystalline and amorphous homogeneous solids plays an important role for example in depth profiling techniques. To verify a faceting mechanism based not only on sputtering by directly impinging ions but also on the contribution of reflected ions and the redeposition of sputtered material a computer simulation has been carried out. The surface in this model is treated as a two-dimensional line segment profile. The model describes the topography evolution on ion bombarded surfaces including the growth mechanism of a facetted surface, using only the interplay of reflected and primary ions and redeposited atoms.

Effects of low and high energy ion bombardment on ETFE polymer

Science.gov (United States)

Minamisawa, R. A.; De Almeida, A.; Abidzina, V.; Parada, M. A.; Muntele, I.; Ila, D.

2007-04-01

The polymer ethylenetetrafluoroethylene (ETFE) is used as anti-adherent coatings for food packages and radiation dosimeters. In this work, we compare the damage induced in ETFE bombarded with 100 keV Si ions with that induced by 1 MeV proton bombardment. The damage depends on the type, energy and intensity of the irradiation. Irradiated films were analyzed with optical absorption photospectrometry, Raman spectroscopy and Fourier transform infrared (FTIR) spectroscopy to determine the chemical nature of the structural changes caused by ion irradiation. Computer simulations were performed to evaluate the radiation damage.

The influence of ion bombardment on emission properties of carbon materials

International Nuclear Information System (INIS)

Chepusov, Alexander; Komarskiy, Alexander; Kuznetsov, Vadim

2014-01-01

When electric-vacuum device works its cathode surface experiences bombardment with ions of residual gases. Effects of ion bombardment impact on surface of field emission cathodes made of carbon materials may essentially change emission properties of such cathodes. It changes emission start electric field strength, voltage vs. current characteristic of material, its relief and electron structure of the surface layer. Field emission cathode operating mode, variation of radiation doses allow to obtain both good effects: maximal electric current, surface recovery – and negative ones: the worst emission properties and surface destruction, amorphization.

The influence of ion bombardment on emission properties of carbon materials

Energy Technology Data Exchange (ETDEWEB)

Chepusov, Alexander, E-mail: chepusov@iep.uran.ru [The Institute of Electrophysics of the Ural Division of the Russian Academy of Sciences (IEP UD RAS), 620016, 106 Amundsen Street, Ekaterinburg (Russian Federation); Ural Federal University, 620002, 19 Mira Street, Ekaterinburg (Russian Federation); Komarskiy, Alexander, E-mail: aakomarskiy@gmail.com [The Institute of Electrophysics of the Ural Division of the Russian Academy of Sciences (IEP UD RAS), 620016, 106 Amundsen Street, Ekaterinburg (Russian Federation); Ural Federal University, 620002, 19 Mira Street, Ekaterinburg (Russian Federation); Kuznetsov, Vadim, E-mail: kuznetsov@iep.uran.ru [The Institute of Electrophysics of the Ural Division of the Russian Academy of Sciences (IEP UD RAS), 620016, 106 Amundsen Street, Ekaterinburg (Russian Federation)

2014-07-01

When electric-vacuum device works its cathode surface experiences bombardment with ions of residual gases. Effects of ion bombardment impact on surface of field emission cathodes made of carbon materials may essentially change emission properties of such cathodes. It changes emission start electric field strength, voltage vs. current characteristic of material, its relief and electron structure of the surface layer. Field emission cathode operating mode, variation of radiation doses allow to obtain both good effects: maximal electric current, surface recovery – and negative ones: the worst emission properties and surface destruction, amorphization.

Thermal performance measurements of a 100 percent polyester MLI [multilayer insulation] system for the Superconducting Super Collider

International Nuclear Information System (INIS)

Gonczy, J.D.; Boroski, W.N.; Niemann, R.C.

1989-09-01

The plastic materials used in the multilayer insulation (MLI) blankets of the superconducting magnets of the Superconducting Super Collider (SSC) are comprised entirely of polyesters. This paper reports on tests conducted in three separate experimental blanket arrangements. The tests explore the thermal performance of two candidate blanket joint configurations each employing a variation of a stepped-butted joint nested between sewn blanket seams. The results from the joint configurations are compared to measurements made describing the thermal performance of the basic blanket materials as tested in an ideal joint configuration. Twenty foil sensors were incorporated within each test blanket to measure interstitial layer and joint layer temperatures. Heat flux and thermal gradients are reported for high and degraded insulating vacuums, and during transient and steady state conditions. In complement with this paper is an associate paper bearing the same title head but with the title extension 'Part 1: Instrumentation and experimental preparation (300K-80K)'. 5 refs., 8 figs., 2 tabs

DML and Foil Measurements of ETA Beam Radius

International Nuclear Information System (INIS)

Nexsen, W; Weir, J

2005-01-01

Simultaneous measurements of the ETA beam radius have been made with a quartz foil and a diamagnetic loop (DML). While the measurements agreed at some settings they diverged at others. While the DML measures the rms radius of the total beam, the foil measures mainly the core and the divergence can be explained by the presence of a low density halo. Evidence of such a halo from other measurements is presented

Alignment and orientation effects in beam-foil experiments

International Nuclear Information System (INIS)

Band, Y.B.

1975-01-01

A theory of the orientation and alignment of atoms observed upon emergence from tilted foils is presented. The interaction with the foil surface is taken into account in the production process of particular states. Once they are produced, the evolution of these states, under the influence of the residual field near the surface, is calculated in the fashion introduced by Eck. The most general effect of this evolution is presented

Method to Increase Performance of Foil Bearings Through Passive Thermal Management

Science.gov (United States)

Bruckner, Robert

2013-01-01

This invention is a new approach to designing foil bearings to increase their load capacity and improve their reliability through passive thermal management. In the present case, the bearing is designed in such a way as to prevent the carryover of lubricant from the exit of one sector to the inlet of the ensuing sector of the foil bearing. When such passive thermal management techniques are used, bearing load capacity is improved by multiples, and reliability is enhanced when compared to current foil bearings. This concept has recently been tested and validated, and shows that load capacity performance of foil bearings can be improved by a factor of two at relatively low speeds with potentially greater relative improvements at higher speeds. Such improvements in performance with respect to speed are typical of foil bearings. Additionally, operation of these newly conceived bearings shows much more reliability and repeatable performance. This trait can be exploited in machine design to enhance safety, reliability, and overall performance. Finally, lower frictional torque has been demonstrated when operating at lower (non-load capacity) loads, thus providing another improvement above the current state of the art. The objective of the invention is to incorporate features into a foil bearing that both enhance passive thermal management and temperature control, while at the same time improve the hydrodynamic (load capacity) performance of the foil bearing. Foil bearings are unique antifriction devices that can utilize the working fluid of a machine as a lubricant (typically air for turbines and motors, liquids for pumps), and as a coolant to remove excess energy due to frictional heating. The current state of the art of foil bearings utilizes forced cooling of the bearing and shaft, which represents poor efficiency and poor reliability. This invention embodies features that utilize the bearing geometry in such a manner as to both support load and provide an inherent and

Intense heavy ion beam-induced effects in carbon-based stripper foils

Energy Technology Data Exchange (ETDEWEB)

Kupka, Katharina

2016-08-15

Amorphous carbon or carbon-based stripper foils are commonly applied in accelerator technology for electron stripping of ions. At the planned facility for antiproton and ion research (FAIR) at the Helmholtzzentrum fuer Schwerionenforschung (GSI), Darmstadt, thin carbon stripper foils provide an option for directly delivering ions of intermediate charge states to the heavy ion synchrotron, SIS 18, in order to mitigate space charge limitations during high-intensity operation. In case of desired high end-energies in the synchrotron, a second stripping process by a thicker carbon foil provides ions of higher charge states for injection into the SIS18. High beam intensities and a pulsed beam structure as foreseen at FAIR pose new challenges to the stripper foils which experience enhanced degradation by radiation damage, thermal effects, and stress waves. In order to ensure reliable accelerator operation, radiation-hard stripper foils are required. This thesis aims to a better understanding of processes leading to degradation of carbon-based thin foils. Special focus is placed on ion-beam induced structure and physical property changes and on the influence of different beam parameters. Irradiation experiments were performed at the M3-beamline of the universal linear accelerator (UNILAC) at GSI, using swift heavy ion beams with different pulse lengths and repetition rates. Tested carbon foils were standard amorphous carbon stripper foils produced by the GSI target laboratory, as well as commercial amorphous and diamond-like carbon foils and buckypaper foils. Microstructural changes were investigated with various methods such as optical microscopy, scanning electron microscopy (SEM), profilometry and chromatic aberration measurements. For the investigation of structural changes X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, high resolution transmission electron microscopy (HRTEM), in-situ Fourier-transform infrared spectroscopy (FTIR) and small angle X

Intense heavy ion beam-induced effects in carbon-based stripper foils

International Nuclear Information System (INIS)

Kupka, Katharina

2016-08-01

Amorphous carbon or carbon-based stripper foils are commonly applied in accelerator technology for electron stripping of ions. At the planned facility for antiproton and ion research (FAIR) at the Helmholtzzentrum fuer Schwerionenforschung (GSI), Darmstadt, thin carbon stripper foils provide an option for directly delivering ions of intermediate charge states to the heavy ion synchrotron, SIS 18, in order to mitigate space charge limitations during high-intensity operation. In case of desired high end-energies in the synchrotron, a second stripping process by a thicker carbon foil provides ions of higher charge states for injection into the SIS18. High beam intensities and a pulsed beam structure as foreseen at FAIR pose new challenges to the stripper foils which experience enhanced degradation by radiation damage, thermal effects, and stress waves. In order to ensure reliable accelerator operation, radiation-hard stripper foils are required. This thesis aims to a better understanding of processes leading to degradation of carbon-based thin foils. Special focus is placed on ion-beam induced structure and physical property changes and on the influence of different beam parameters. Irradiation experiments were performed at the M3-beamline of the universal linear accelerator (UNILAC) at GSI, using swift heavy ion beams with different pulse lengths and repetition rates. Tested carbon foils were standard amorphous carbon stripper foils produced by the GSI target laboratory, as well as commercial amorphous and diamond-like carbon foils and buckypaper foils. Microstructural changes were investigated with various methods such as optical microscopy, scanning electron microscopy (SEM), profilometry and chromatic aberration measurements. For the investigation of structural changes X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, high resolution transmission electron microscopy (HRTEM), in-situ Fourier-transform infrared spectroscopy (FTIR) and small angle X

Particle-In-Cell/Monte Carlo Simulation of Ion Back Bombardment in Photoinjectors

International Nuclear Information System (INIS)

Qiang, Ji; Corlett, John; Staples, John

2009-01-01

In this paper, we report on studies of ion back bombardment in high average current dc and rf photoinjectors using a particle-in-cell/Monte Carlo method. Using H 2 ion as an example, we observed that the ion density and energy deposition on the photocathode in rf guns are order of magnitude lower than that in a dc gun. A higher rf frequency helps mitigate the ion back bombardment of the cathode in rf guns

Finite Element Modelling of Bends and Creases during Folding Ultra Thin Stainless Steel Foils

NARCIS (Netherlands)

Datta, K.; Akagi, H.; Geijselaers, Hubertus J.M.; Huetink, Han

2003-01-01

Finite Element Modelling of an ultra thin foil of SUS 304 stainless steel is carried out. These foils are 20 mm and below in thickness. The development of stresses and strains during folding of these foils is studied. The objective of this study is to induce qualities of paper in the foils of

Compressor ported shroud for foil bearing cooling

Science.gov (United States)

Elpern, David G [Los Angeles, CA; McCabe, Niall [Torrance, CA; Gee, Mark [South Pasadena, CA

2011-08-02

A compressor ported shroud takes compressed air from the shroud of the compressor before it is completely compressed and delivers it to foil bearings. The compressed air has a lower pressure and temperature than compressed outlet air. The lower temperature of the air means that less air needs to be bled off from the compressor to cool the foil bearings. This increases the overall system efficiency due to the reduced mass flow requirements of the lower temperature air. By taking the air at a lower pressure, less work is lost compressing the bearing cooling air.

Evidence Supporting an Early as Well as Late Heavy Bombardment on the Moon

Science.gov (United States)

Frey, Herbert

2015-01-01

Evidence supporting an intense early bombardment on the Moon in addition to the traditional Late Heavy Bombardment at approx. 4 BY ago include the distribution of N(50) Crater Retention Ages (CRAs) for candidate basins, a variety of absolute age scenarios for both a "young" and an "old" Nectaris age, and the decreasing contrasts in both topographic relief and Bouguer gravity with increasing CRA.

Electrochemical etching of a niobium foil in methanolic HF for electrolytic capacitor

International Nuclear Information System (INIS)

Kim, Kyungmin; Park, Jiyoung; Cha, Gihoon; Yoo, Jeong Eun; Choi, Jinsub

2013-01-01

Electrochemical etching of niobium foil in order to enlarge the surface area for the application in electrolytic capacitor was carried out in a methanolic electrolyte. We found that the pit density and depth are not linearly proportional to concentration of HF and applied potential: there is the optimal concentration of HF at each applied potential. The optimal etching condition was obtained at 50 V in 0.99 vol.% HF, which exhibited the capacitance of 350 μF cm −2 . Pit density and depth of pits on electrochemical etched Nb foil under different conditions were counted from SEM images and electrochemical impedance spectroscopy (EIS) of the etched Nb foils was carried out for the capacitance measurement. Equivalent circuit model showing less than 5% error was suggested for applying to the etched niobium foil. - Highlights: • Surface enlargement of Nb foil can be achieved by electrochemical etching in methanolic HF. • Electrolytic capacitor of etched niobium foil exhibits a capacitance of 350 μF cm −2 . • The method provides a way of developing commercially viable process

Validation of calculated self-shielding factors for Rh foils

Science.gov (United States)

Jaćimović, R.; Trkov, A.; Žerovnik, G.; Snoj, L.; Schillebeeckx, P.

2010-10-01

Rhodium foils of about 5 mm diameter were obtained from IRMM. One foil had thickness of 0.006 mm and three were 0.112 mm thick. They were irradiated in the pneumatic transfer system and in the carousel facility of the TRIGA reactor at the Jožef Stefan Institute. The foils were irradiated bare and enclosed in small cadmium boxes (about 2 g weight) of 1 mm thickness to minimise the perturbation of the local neutron flux. They were co-irradiated with 5 mm diameter and 0.2 mm thick Al-Au (0.1%) alloy monitor foils. The resonance self-shielding corrections for the 0.006 and 0.112 mm thick samples were calculated by the Monte Carlo simulation and amount to about 10% and 60%, respectively. The consistency of measurements confirmed the validity of self-shielding factors. Trial estimates of Q0 and k0 factors for the 555.8 keV gamma line of 104Rh were made and amount to 6.65±0.18 and (6.61±0.12)×10 -2, respectively.

Modified Monkman–Grant relationship for austenitic stainless steel foils

Energy Technology Data Exchange (ETDEWEB)

Osman Ali, Hassan, E-mail: hassaninsan@gmail.com [Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor (Malaysia); Tamin, Mohd Nasir, E-mail: taminmn@fkm.utm.my [Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor (Malaysia)

2013-02-15

Characteristics of creep deformation for austenitic stainless steel foils are examined using the modified Monkman–Grant equation. A series of creep tests are conducted on AISI 347 steel foils at 700 °C and different stress levels ranging from 54 to 221 MPa. Results showed that at lower stress levels below 110 MPa, the creep life parameters ε{sub min},ε{sub r},t{sub r} can be expressed using the modified Monkman–Grant equation with exponent m′= 0.513. This indicates significant deviation of the creep behavior from the first order reaction kinetics theory for creep (m′ = 1.0). The true tertiary creep damage in AISI 347 steel foil begins after 65.9% of the creep life of the foil has elapsed at stress levels above 150 MPa. At this high stress levels, Monkman–Grant ductility factor λ{sup ′} saturates to a value of 1.3 with dislocation-controlled deformation mechanisms operating. At low stress levels, λ{sup ′} increases drastically (λ{sup ′}=190 at 54 MPa) when slow diffusion-controlled creep is dominant.

Effects of polymer corrosion inhibitor on widening etch tunnels of aluminum foil for capacitor

International Nuclear Information System (INIS)

Ban, Chaolei; He, Yedong; Shao, Xin; Wang, Zhishen

2014-01-01

Highlights: •With PSSA, the exterior surface dissolution of etched Al foil is suppressed. •With PSSA, the interior surface dissolution of etched Al foil is facilitated. •With PSSA, the tunnels are widened along the entire length. •With PSSA, the area and capacitance of etched Al foil are significantly improved. -- Abstract: We investigated the effects of polymeric corrosion inhibitor polystyrene sulfonic acid (PSSA) additive to 3% HNO 3 solution on widening tunnels of pre-etched aluminum foil by electrochemical DC etching for aluminum electrolytic capacitors, using scanning electron microscopy and polarization curves. With trace PSSA, the dissolution of exterior surface of etch tunnels of Al foil is suppressed and the dissolution of interior surface of etch tunnels of Al foil is facilitated, respectively. The tunnels transform from circular cone to circular column in shape and pits-merging on the surface is weakened, leading to significant increase in the surface area and specific capacitance of the Al foil. The amounts of reduced thickness and weight of Al foil during the widening process of etch tunnels can be decreased if PSSA is employed

Silicon transport in sputter-deposited tantalum layers grown under ion bombardment

International Nuclear Information System (INIS)

Gallais, P.; Hantzpergue, J.J.; Remy, J.C.; Roptin, D.

1988-01-01

Tantalum was sputter deposited on (111) Si substrate under low-energy ion bombardment in order to study the effects of the ion energy on the silicon transport into the Ta layer. The Si substrate was heated up to 500 0 C during growth. For ion energies up to 180 eV silicon is not transported into tantalum and the growth temperature has no effect. An ion bombardment energy of 280 eV enhances the transport of silicon throughout the tantalum layer. Growth temperatures up to 300 0 C have no effect on the silicon transport which is mainly enhanced by the ion bombardment. For growth temperatures between 300 and 500 0 C, the silicon transport is also enhanced by the thermal diffusion. The experimental depth distribution of silicon is similar to the theoretical depth distribution calculated for the case of an interdiffusion. The ion-enhanced process of silicon transport is characterized by an activation energy of 0.4 eV. Silicon into the layers as-grown at 500 0 C is in both states, amorphous silicide and microcrystalline cubic silicon

Structural and magnetic properties of ion-beam bombarded Co/Pt multilayers

Energy Technology Data Exchange (ETDEWEB)

Lin, K.W.; Guo, J.Y.; Lin, S.R.; Ouyang, H. [Department of Materials Science and Engineering, National Chung Hsing University, Taichung 402 (China); Tsai, C.J. [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300 (China); Van Lierop, J. [Department of Physics and Astronomy, University of Manitoba, Winnipeg (Canada); Phuoc, N.N.; Suzuki, T. [Information Storage Materials Laboratory, Toyota Technological Institute, Nagoya 468-8511 (Japan)

2007-12-15

A series of [Pt(2 nm)/Co(2 nm)]{sub 10}/Pt(30 nm) multilayers were deposited by using an ion-beam technique. X-ray diffraction and transmission electron microscopy results have shown that as-deposited samples consist of h.c.p. Co and f.c.c. Pt phases. Disordered CoPt{sub 3} phases were developed with increasing End-Hall voltage (V{sub EH}) that induces greater ion-beam bombardment energy during deposition. This indicates that intermixing of Co and Pt increases with ion-beam bombardment. The coercivities (ranging from 100 Oe to 300 Oe) of Co/Pt multilayers decreased with increasing V{sub EH}. After annealing, the formation of CoPt{sub 3} was observed in these ion-beam bombarded samples, resulting in lower coercivities (H{sub c}{proportional_to} 50 Oe). The depressed transition temperature of CoPt{sub 3} for films deposited with the largest V{sub EH} was attributed to distorted CoPt{sub 3} structures that appeared with annealing. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Development of single mask GEM foils in India

International Nuclear Information System (INIS)

Pant, L.M.; Mohanty, A.K.; Pinto, O.J.; Gadhadharan, S.; Menon, Pradeep; Sharma, Archana; Oliveira, Rui De; )

2014-01-01

There are various techniques available around the globe for making punch through holes for Micro Pattern Gas Detectors (MPGDs), such as Gas Electron Multipliers (GEMs). The GEM foils consists of 5 μm of Cu clad on both the sides of 50 μm polymide (PMMA/kapton) (5/50/5). At present these foils are developed in South Korea without having any adhesive between the Cu and polymide. The available techniques range from chemical etching, reactive plasma etching and laser etching. However, for GEM detectors, having an active area upto 5000 cm 2 , the chemical etching process using a Single Mask has been developed at CERN which is faster from the viewpoint of mass production of such foils for the upgrades which are foreseen in a couple of years with the Large Hadron Collider facility at CERN

Modeling of high-pressure generation using the laser colliding foil technique

Energy Technology Data Exchange (ETDEWEB)

Fabbro, R.; Faral, B.; Virmont, J.; Cottet, F.; Romain, J.P.

1989-03-01

An analytical model describing the collision of two foils is presented and applied to the collision of laser-accelerated foils. Numerical simulations have been made to verify this model and to compare its results in the case of laser-accelerated foils. Scaling laws relating the different parameters (shock pressure, laser intensity, target material, etc.) have been established. The application of this technique to high-pressure equation of state experiments is then discussed.

Modeling of high-pressure generation using the laser colliding foil technique

International Nuclear Information System (INIS)

Fabbro, R.; Faral, B.; Virmont, J.; Cottet, F.; Romain, J.P.

1989-01-01

An analytical model describing the collision of two foils is presented and applied to the collision of laser-accelerated foils. Numerical simulations have been made to verify this model and to compare its results in the case of laser-accelerated foils. Scaling laws relating the different parameters (shock pressure, laser intensity, target material, etc.) have been established. The application of this technique to high-pressure equation of state experiments is then discussed

An ion beam deceleration lens for ultra-low-energy ion bombardment of naked DNA

Energy Technology Data Exchange (ETDEWEB)

Thopan, P.; Prakrajang, K. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongkumkoon, P. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Suwannakachorn, D. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, L.D., E-mail: yuldyuld@gmail.com [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

2013-07-15

Highlights: ► An ion beam deceleration lens was designed and constructed. ► The deceleration lens was installed and tested. ► The decelerated ion beam energy was measured using an electrical field. ► Decelerated ultra-low-energy ion beam bombarded naked DNA. ► Ion beam with energy of a few tens of eV could break DNA strands. -- Abstract: Study of low-energy ion bombardment effect on biological living materials is of significance. High-energy ion beam irradiation of biological materials such as organs and cells has no doubt biological effects. However, ion energy deposition in the ion-bombarded materials dominantly occurs in the low-energy range. To investigate effects from very-low-energy ion bombardment on biological materials, an ion beam deceleration lens is necessary for uniform ion energy lower than keV. A deceleration lens was designed and constructed based on study of the beam optics using the SIMION program. The lens consisted of six electrodes, able to focus and decelerate primary ion beam, with the last one being a long tube to obtain a parallel uniform exiting beam. The deceleration lens was installed to our 30-kV bioengineering-specialized ion beam line. The final decelerated-ion energy was measured using a simple electrostatic field to bend the beam to range from 10 eV to 1 keV controlled by the lens parameters and the primary beam condition. In a preliminary test, nitrogen ion beam at 60 eV decelerated from a primary 20-keV beam bombarded naked plasmid DNA. The original DNA supercoiled form was found to change to relaxed and linear forms, indicating single or double strand breaks. The study demonstrated that the ion bombardment with energy as low as several-tens eV was possible to break DNA strands and thus potential to cause genetic modification of biological cells.

An ion beam deceleration lens for ultra-low-energy ion bombardment of naked DNA

International Nuclear Information System (INIS)

Thopan, P.; Prakrajang, K.; Thongkumkoon, P.; Suwannakachorn, D.; Yu, L.D.

2013-01-01

Highlights: ► An ion beam deceleration lens was designed and constructed. ► The deceleration lens was installed and tested. ► The decelerated ion beam energy was measured using an electrical field. ► Decelerated ultra-low-energy ion beam bombarded naked DNA. ► Ion beam with energy of a few tens of eV could break DNA strands. -- Abstract: Study of low-energy ion bombardment effect on biological living materials is of significance. High-energy ion beam irradiation of biological materials such as organs and cells has no doubt biological effects. However, ion energy deposition in the ion-bombarded materials dominantly occurs in the low-energy range. To investigate effects from very-low-energy ion bombardment on biological materials, an ion beam deceleration lens is necessary for uniform ion energy lower than keV. A deceleration lens was designed and constructed based on study of the beam optics using the SIMION program. The lens consisted of six electrodes, able to focus and decelerate primary ion beam, with the last one being a long tube to obtain a parallel uniform exiting beam. The deceleration lens was installed to our 30-kV bioengineering-specialized ion beam line. The final decelerated-ion energy was measured using a simple electrostatic field to bend the beam to range from 10 eV to 1 keV controlled by the lens parameters and the primary beam condition. In a preliminary test, nitrogen ion beam at 60 eV decelerated from a primary 20-keV beam bombarded naked plasmid DNA. The original DNA supercoiled form was found to change to relaxed and linear forms, indicating single or double strand breaks. The study demonstrated that the ion bombardment with energy as low as several-tens eV was possible to break DNA strands and thus potential to cause genetic modification of biological cells

The surface topography of Inconel, stainless steel and copper after argon ion bombardment

International Nuclear Information System (INIS)

Vogelbruch, K.; Vietzke, E.

1983-01-01

Energetic particle bombardment of metals is known to change the surface topography. To simulate the behaviour of the first wall of a fusion device under real plasma conditions, we have investigated the surface topography of rotating targets after 30 keV argon ion bombardment at 70deg incident angle by electron scanning micrographs. Under these conditions Inconel 600, 601, 625, stainless steel, and copper showed no cones, pyramids or cliffs, but only etching figures and at higher ion doses relatively flat hills. Thus, it can be concluded, that the influence of energetic particles on the first wall of a fusion reactor is smaller than expected from the results of such sputtering experiments, which have dealt with the formation of surface structures under ion bombardment at constant incident direction. (author)

Microchannel neural interface manufacture by stacking silicone and metal foil laminae

Science.gov (United States)

Lancashire, Henry T.; Vanhoestenberghe, Anne; Pendegrass, Catherine J.; Ajam, Yazan Al; Magee, Elliot; Donaldson, Nick; Blunn, Gordon W.

2016-06-01

Objective. Microchannel neural interfaces (MNIs) overcome problems with recording from peripheral nerves by amplifying signals independent of node of Ranvier position. Selective recording and stimulation using an MNI requires good insulation between microchannels and a high electrode density. We propose that stacking microchannel laminae will improve selectivity over single layer MNI designs due to the increase in electrode number and an improvement in microchannel sealing. Approach. This paper describes a manufacturing method for creating MNIs which overcomes limitations on electrode connectivity and microchannel sealing. Laser cut silicone—metal foil laminae were stacked using plasma bonding to create an array of microchannels containing tripolar electrodes. Electrodes were DC etched and electrode impedance and cyclic voltammetry were tested. Main results. MNIs with 100 μm and 200 μm diameter microchannels were manufactured. High electrode density MNIs are achievable with electrodes present in every microchannel. Electrode impedances of 27.2 ± 19.8 kΩ at 1 kHz were achieved. Following two months of implantation in Lewis rat sciatic nerve, micro-fascicles were observed regenerating through the MNI microchannels. Significance. Selective MNIs with the peripheral nervous system may allow upper limb amputees to control prostheses intuitively.

Experimental and theoretical analysis of a rigid rotor supported by air foil bearings

DEFF Research Database (Denmark)

Larsen, Jon Steffen; Hansen, Asger J. T.; Santos, Ilmar

2015-01-01

The popularity of compressors utilizing foil bearings is increasing. Their mechanical design is challenging, and an accurate prediction of the bearing coefficients is important. A mathematical model taking into account the foil structure, and the detailed geometry of a three pad foil bearing...

HCN Production via Impact Ejecta Reentry During the Late Heavy Bombardment

Science.gov (United States)

Parkos, Devon; Pikus, Aaron; Alexeenko, Alina; Melosh, H. Jay

2018-04-01

Major impact events have shaped the Earth as we know it. The Late Heavy Bombardment is of particular interest because it immediately precedes the first evidence of life. The reentry of impact ejecta creates numerous chemical by-products, including biotic precursors such as HCN. This work examines the production of HCN during the Late Heavy Bombardment in more detail. We stochastically simulate the range of impacts on the early Earth and use models developed from existing studies to predict the corresponding ejecta properties. Using multiphase flow methods and finite-rate equilibrium chemistry, we then find the HCN production due to the resulting atmospheric heating. We use Direct Simulation Monte Carlo to develop a correction factor to account for increased yields due to thermochemical nonequilibrium. We then model 1-D atmospheric turbulent diffusion to find the time accurate transport of HCN to lower altitudes and ultimately surface water. Existing works estimate the necessary HCN molarity threshold to promote polymerization that is 0.01 M. For a mixing depth of 100 m, we find that the Late Heavy Bombardment will produce at least one impact event above this threshold with probability 24.1% for an oxidized atmosphere and 56.3% for a partially reduced atmosphere. For a mixing depth of 10 m, the probability is 79.5% for an oxidized atmosphere and 96.9% for a partially reduced atmosphere. Therefore, Late Heavy Bombardment impact ejecta is likely an HCN source sufficient for polymerization in shallow bodies of water, particularly if the atmosphere were in a partially reduced state.

Exploding metallic fuse physics experiments

International Nuclear Information System (INIS)

Goforth, J.H.; Hackett, K.E.; Lindemuth, I.R.; Lopez, E.A.; McCullough, W.F.; Dona, H.; Reinovsky, R.E.

1986-01-01

The ultimate practicality of inductive pulse compression systems as drivers for energetic plasma implosions hinges on the development of a suitable opening switch capable of interrupting tons of megamp currents in time scales of a few hundred nanoseconds while withstanding L(dI/dt) voltages of a megavolt or more. 1. Exploding metallic foils (fuses) are a candidate for switching elements in the inductive store pulsed power systems used in the Los Alamos and Air Force Weapons Laboratory foil implosion X-ray source generation programs. To verify or modify new theoretical and computational predictions about the electrical and hydrodynamic behavior of exploding metallic foils used as fuses. The authors have initiated a new series of small scale capacitor bank driven fuse experiments. The experiments represent an extension of previous experiments, but in the new series a foil geometry more amenable to theoretical and computational analysis is used. The metallic foil (aluminum or copper) is laminated between two thin layers of insulating material (mylar or kaptan). Adjacent to one layer of insulation is a much heavier backing insulator (polyethylene) whereas air is adjacent to the other layer. Because of the differing masses on the two sides of the foil, the foil expansion and hydrodynamic motion is essentially one-sided and the layer of insulation on the expanding side becomes a readily-characterizable ''flyer'' which provides a controlled amount of hydrodynamic tamping. In addition to the usual voltage, current, and dI/dt electrical measurements, time-resolved spectrometer measurements are used to determine the temperature of the expanding metallic foil. Post-shot examination of the flyer and the insulation impacted by the flyer gives insight into the experimental behavior

Lead foil in dental X-ray film: Backscattering rejection or image intensifier?

International Nuclear Information System (INIS)

Hönnicke, M.G.; Delben, G.J.; Godoi, W.C.; Swinka-Filho, V.

2014-01-01

Dental X-ray films are still largely used due to sterilization issues, simplicity and, mainly, economic reasons. These films almost always are double coated (double emulsion) and have a lead foil in contact with the film for X-ray backscattering rejection. Herein we explore the use of the lead foil as an image intensifier. In these studies, spatial resolution was investigated when images were acquired on the dental X-ray films with and without the lead foil. Also, the lead foil was subjected to atomic analysis (fluorescent measurements) and structure analysis (X-ray diffraction). We determined that the use of the lead foil reduces the exposure time, however, does not affect the spatial resolution on the acquired images. This suggests that the fluorescent radiation spread is smaller than the grain sizes of the dental X-ray films

Lead foil in dental X-ray film: Backscattering rejection or image intensifier?

Science.gov (United States)

Hönnicke, M. G.; Delben, G. J.; Godoi, W. C.; Swinka-Filho, V.

2014-11-01

Dental X-ray films are still largely used due to sterilization issues, simplicity and, mainly, economic reasons. These films almost always are double coated (double emulsion) and have a lead foil in contact with the film for X-ray backscattering rejection. Herein we explore the use of the lead foil as an image intensifier. In these studies, spatial resolution was investigated when images were acquired on the dental X-ray films with and without the lead foil. Also, the lead foil was subjected to atomic analysis (fluorescent measurements) and structure analysis (X-ray diffraction). We determined that the use of the lead foil reduces the exposure time, however, does not affect the spatial resolution on the acquired images. This suggests that the fluorescent radiation spread is smaller than the grain sizes of the dental X-ray films.

Self-propulsion of a pitching foil

Science.gov (United States)

Das, Anil; Shukla, Ratnesh; Govardhan, Raghuraman

2017-11-01

Undulatory motions serve as a fundamental mechanism for bio-locomotion at moderate and high Reynolds numbers. An understanding of the interactions between self-propelling undulatory motions and the surrounding fluid, not only provides insight into the efficiency of bio-locomotion, but also yields valuable pointers for the design of autonomous under-water and micro-aerial vehicles. Here, we investigate a simplified model of a self-propelling pitching foil that undergoes time-periodic oscillations about its quarter chord. We consider two-dimensional configurations in which the foil is free to propel along only longitudinal and both transverse and longitudinal directions. In both the configurations, the time-averaged self-propelling velocity increases monotonically with the Reynolds number Re (based on trailing edge speed and chord as the characteristic velocity and length). The rate of increase is particularly pronounced in the low Re regime (Re spaced wake vortices dissipate within a few chord lengths. At moderate and high Re, the wake exhibits increasingly complex structure in both the configurations. For a fixed Re, the foil with a single translational degree of freedom propels at a higher speed for a higher input power requirement. Differences between the two configurations will be discussed within the context of undulatory self-propulsion observed in nature.

Goal-directed mechanisms that constrain retrieval predict subsequent memory for new "foil" information.

Science.gov (United States)

Vogelsang, David A; Bonnici, Heidi M; Bergström, Zara M; Ranganath, Charan; Simons, Jon S

2016-08-01

To remember a previous event, it is often helpful to use goal-directed control processes to constrain what comes to mind during retrieval. Behavioral studies have demonstrated that incidental learning of new "foil" words in a recognition test is superior if the participant is trying to remember studied items that were semantically encoded compared to items that were non-semantically encoded. Here, we applied subsequent memory analysis to fMRI data to understand the neural mechanisms underlying the "foil effect". Participants encoded information during deep semantic and shallow non-semantic tasks and were tested in a subsequent blocked memory task to examine how orienting retrieval towards different types of information influences the incidental encoding of new words presented as foils during the memory test phase. To assess memory for foils, participants performed a further surprise old/new recognition test involving foil words that were encountered during the previous memory test blocks as well as completely new words. Subsequent memory effects, distinguishing successful versus unsuccessful incidental encoding of foils, were observed in regions that included the left inferior frontal gyrus and posterior parietal cortex. The left inferior frontal gyrus exhibited disproportionately larger subsequent memory effects for semantic than non-semantic foils, and significant overlap in activity during semantic, but not non-semantic, initial encoding and foil encoding. The results suggest that orienting retrieval towards different types of foils involves re-implementing the neurocognitive processes that were involved during initial encoding. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Effect of helium ion bombardment on hydrogen behaviour in stainless steel

International Nuclear Information System (INIS)

Guseva, M.I.; Stolyarova, V.G.; Gorbatov, E.A.

1987-01-01

The effect of helium ion bombardment on hydrogen behaviour in 12Kh18N10T stainless steel is investigated. Helium and hydrogen ion bombardment was conducted in the ILU-3 ion accelerator; the fluence and energy made up 10 16 -5x10 17 cm -2 , 30 keV and 10 16 -5x10 18 cm -2 , 10 keV respectively. The method of recoil nuclei was used for determination of helium and hydrogen content. Successive implantation of helium and hydrogen ions into 12Kh18N10T stainless steel results in hydrogen capture by defects formed by helium ions

Elevated Temperature Tensile Tests on DU–10Mo Rolled Foils

Energy Technology Data Exchange (ETDEWEB)

Schulthess, Jason [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2014-09-01

Tensile mechanical properties for uranium-10 wt.% molybdenum (U–10Mo) foils are required to support modeling and qualification of new monolithic fuel plate designs. It is expected that depleted uranium-10 wt% Mo (DU–10Mo) mechanical behavior is representative of the low enriched U–10Mo to be used in the actual fuel plates, therefore DU-10Mo was studied to simplify material processing, handling, and testing requirements. In this report, tensile testing of DU-10Mo fuel foils prepared using four different thermomechanical processing treatments were conducted to assess the impact of foil fabrication history on resultant tensile properties.

Gas permeability of thin polyimide foils prepared by in-situ polymerisation

International Nuclear Information System (INIS)

Stolarz, Anna; Varlam, Mihai; Wellum, Roger

2008-01-01

The entrance windows to the gas detector chambers as well as to the target containers used in high-energy and high-intensity accelerators must be as thin as possible to minimise energy losses of the particles used in astrophysics and nuclear physics studies. Because of their good physical properties, polyimide foils are often considered as suitable material for such windows, but commercially available foils, having a thickness greater than 7-8 μm (>1 mg/cm 2 ), would cause energy losses of particles significant for some nuclear reactions studied. Foils prepared by in-situ polymerisation can, however, be as thin as 0.07 μm (∼10 μg/cm 2 ). The permeability of 4 μm foils produced by in-situ polymerisation has been measured at room temperature for He and Ar. For He measurements were performed in the pressure range of 4-70 mbar and for Ar in the range of 20-140 mbar and the permeability was found to be in good agreement with the values published for the thicker commercial foils

Large thermal protection system panel

Science.gov (United States)

Weinberg, David J. (Inventor); Myers, Franklin K. (Inventor); Tran, Tu T. (Inventor)

2003-01-01

A protective panel for a reusable launch vehicle provides enhanced moisture protection, simplified maintenance, and increased temperature resistance. The protective panel includes an outer ceramic matrix composite (CMC) panel, and an insulative bag assembly coupled to the outer CMC panel for isolating the launch vehicle from elevated temperatures and moisture. A standoff attachment system attaches the outer CMC panel and the bag assembly to the primary structure of the launch vehicle. The insulative bag assembly includes a foil bag having a first opening shrink fitted to the outer CMC panel such that the first opening and the outer CMC panel form a water tight seal at temperatures below a desired temperature threshold. Fibrous insulation is contained within the foil bag for protecting the launch vehicle from elevated temperatures. The insulative bag assembly further includes a back panel coupled to a second opening of the foil bag such that the fibrous insulation is encapsulated by the back panel, the foil bag, and the outer CMC panel. The use of a CMC material for the outer panel in conjunction with the insulative bag assembly eliminates the need for waterproofing processes, and ultimately allows for more efficient reentry profiles.

Neutron yields from bombardment of α-particles

International Nuclear Information System (INIS)

Nakasima, Ryuzo

1982-09-01

The thick target neutron yields from bombardment of <10 MeV α-particles are calculated based on the reaction cross sections. The results for the elements of Z < 15 are compared with existing calculated or measured neutron yield data. For the elements of 16 < Z < 50, elemental or isotopic neutron yields are calculated if the cross section data are available. (author)

The target-to-foils shift in simultaneous and sequential lineups.

Science.gov (United States)

Clark, Steven E; Davey, Sherrie L

2005-04-01

A theoretical cornerstone in eyewitness identification research is the proposition that witnesses, in making decisions from standard simultaneous lineups, make relative judgments. The present research considers two sources of support for this proposal. An experiment by G. L. Wells (1993) showed that if the target is removed from a lineup, witnesses shift their responses to pick foils, rather than rejecting the lineups, a result we will term a target-to-foils shift. Additional empirical support is provided by results from sequential lineups which typically show higher accuracy than simultaneous lineups, presumably because of a decrease in the use of relative judgments in making identification decisions. The combination of these two lines of research suggests that the target-to-foils shift should be reduced in sequential lineups relative to simultaneous lineups. Results of two experiments showed an overall advantage for sequential lineups, but also showed a target-to-foils shift equal in size for simultaneous and sequential lineups. Additional analyses indicated that the target-to-foils shift in sequential lineups was moderated in part by an order effect and was produced with (Experiment 2) or without (Experiment 1) a shift in decision criterion. This complex pattern of results suggests that more work is needed to understand the processes which underlie decisions in simultaneous and sequential lineups.

Quantification of steroid conjugates using fast atom bombardment mass spectrometry

International Nuclear Information System (INIS)

Gaskell, S.J.

1990-01-01

Fast atom bombardment/mass spectrometry or liquid secondary ion mass spectrometry provides the capability for direct analysis of steroid conjugates (sulfates, glucuronides) without prior hydrolysis or derivatization. During the analysis of biologic extracts, limitations on the sensitivity of detection arise from the presence of co-extracted material which may suppress or obscure the analyte signal. A procedure is described for the quantitative determination of dehydroepiandrosterone sulfate in serum which achieved selective isolation of the analyte using immunoadsorption extraction and highly specific detection using tandem mass spectrometry. A stable isotope-labeled analog [( 2H2]dehydroepiandrosterone sulfate) was used as internal standard. Fast atom bombardment of dehydroepiandrosterone sulfate yielded abundant [M-H]- ions that fragmented following collisional activation to give HSO4-; m/z 97. During fast atom bombardment/tandem mass spectrometry of serum extracts, a scan of precursor ions fragmenting to give m/z 97 detected dehydroepiandrosterone sulfate and the [2H2]-labeled analog with a selectivity markedly superior to that observed using conventional mass spectrometry detection. Satisfactory agreement was observed between quantitative data obtained in this way and data obtained by gas chromatography/mass spectrometry of the heptafluorobutyrates of dehydroepiandrosterone sulfate and [2H2]dehydroepiandrosterone sulfate obtained by direct derivatization. 21 refs

Acceleration of polyethelene foils by laser driven ablation

International Nuclear Information System (INIS)

Ahlstrom, H.G.; Burginyon, G.A.; Haas, R.A.

1974-01-01

The production of thermonuclear energy, by laser driven implosion of spherical DT shells, with achievable laser technology, requires the development of an efficient and stable implosion. Certain aspects of the acceleration of the spherical shells can be studied experimentally by irradiating thin, 5 to 25 μm, polyethelene foils. The results of foil acceleration experiments performed using a Nd:YAG-Glass laser capable of producing 150 J, 1 nsec pulses will be discussed. The dynamics of the accelerated foil, the ion blow off, high energy electron spectrum (6 to 180 keV), x-ray spectrum (1 to 150 keV) the spatial distribution of the x-ray emission, the laser beam focal spot energy distribution, the laser temporal pulse shape and spectrum for reflected and transmitted radiation have all been measured simultaneously. The results of these measurements are compared with detailed numerical simulations. (U.S.)

Characteristics of a plasma flow field produced by a metal array bridge foil explosion

Science.gov (United States)

Junying, WU; Long, WANG; Yase, LI; Lijun, YANG; Manzoor, SULTAN; Lang, CHEN

2018-07-01

To improve the energy utilization efficiency of metal bridge foil explosion, and increase the function range of plasmas, array bridge foil explosion experiments with different structures were performed. A Schlieren photographic measurement system with a double-pulse laser source was used to observe the flow field of a bridge foil explosion. The evolution laws of plasmas and shock waves generated by array bridge foil explosions of different structures were analyzed and compared. A multi-phase flow calculation model was established to simulate the electrical exploding process of a metal bridge foil. The plasma equation of state was determined by considering the effect of the changing number of particles and Coulomb interaction on the pressure and internal energy. The ionization degree of the plasma was calculated via the Saha–Eggert equation assuming conditions of local thermal equilibrium. The exploding process of array bridge foils was simulated, and the superposition processes of plasma beams were analyzed. The variation and distribution laws of the density, temperature, pressure, and other important parameters were obtained. The results show that the array bridge foil has a larger plasma jet diameter than the single bridge foil for an equal total area of the bridge foil. We also found that the temperature, pressure, and density of the plasma jet’s center region sharply increase because of the superposition of plasma beams.

Forensic discrimination of aluminum foil by SR-XRF and ICP-AES

International Nuclear Information System (INIS)

Kasamatsu, Masaaki; Suzuki, Yasuhiro; Suzuki, Shinichi; Miyamoto, Naoki; Watanabe, Seiya; Shimoda, Osamu; Takatsu, Masahisa; Nakanishi, Toshio

2010-01-01

The application of synchrotron radiation X-ray fluorescence spectrometry (SR-XRF) was investigated for the forensic discrimination of aluminum foil by comparisons of the elemental components. Small fragments (1 x 1 mm) were taken from 4 kinds of aluminum foils produced by different manufactures and used for measurements of the XRF spectrum at BL37XU of SPring-8. A comparison of the XRF spectra was effective for the discrimination of aluminum foils from different sources, because significant differences were observed in the X-ray peak intensities of Fe, Cu, Zn, Ga, Zr and Sn. These elements, except for Zr and Sn in the aluminum foils and NIST SRM1258 (Aluminium Alloy 6011), were also determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The observed values of Fe, Cu, Zn and Ga in NIST standard samples by ICP-AES showed satisfactorily good agreements with the certified or information values with relative standard deviations from 1.1% for Zn to 6.7% for Ga. The observed values for the aluminum foils by ICP-AES were compared with those by SR-XRF. Correlation coefficients from 0.997 for Cu/Fe to 0.999 for Zn/Fe and Ga/Fe were obtained between the ratio of the elemental concentration by ICP-AES and normalized the X-ray intensity by SR-XRF. This result demonstrates that a comparison of the normalized X-ray intensity is nearly as effective for the discrimination of aluminum foils as quantitative analysis by ICP-AES. Comparisons of the analytical results by SR-XRF allow the discrimination of all aluminum foils using only a 1 mm 2 fragment with no destruction of the samples. (author)

The effect of chordwise flexibility on flapping foil propulsion in quiescent fluid

Science.gov (United States)

Shinde, Sachin; Arakeri, Jaywant

2010-11-01

Motivated to understand the role of wing flexibility of flying creatures during hovering, we experimentally study the effect of chordwise flexibility on the flow generated in quiescent fluid by a sinusoidally pitching rigid symmetrical foil with a flexible flap attached at the trailing edge. This foil produces a narrow, coherent jet containing reverse Karman vortex street, and a corresponding thrust. The thrust and flow is similar to that produced by a hovering bird or insect, however the mechanism seems to be different from known hovering mechanisms. Novelty of the present hovering mechanism is that the thrust generation is due to the coordinated pushing action of rigid foil and flexible flap. We identify the flow and vortex generation mechanism. This foil produces jet flows over a range of flapping frequencies and amplitudes. In contrast, the foil without flap i.e. with rigid trailing edge produces a weak, divergent jet that meanders randomly. Appending a flexible flap to the foil suppresses jet-meandering and strengthens the jet. Flexibility of flap is crucial in determining the flow structure. This study is useful in designing MAVs and thrusters.

Charging of insulators by multiply-charged-ion impact probed by slowing down of fast binary-encounter electrons

Science.gov (United States)

de Filippo, E.; Lanzanó, G.; Amorini, F.; Cardella, G.; Geraci, E.; Grassi, L.; La Guidara, E.; Lombardo, I.; Politi, G.; Rizzo, F.; Russotto, P.; Volant, C.; Hagmann, S.; Rothard, H.

2010-12-01

The interaction of ion beams with insulators leads to charging-up phenomena, which at present are under investigation in connection with guiding phenomena in nanocapillaries with possible application in nanofocused beams. We studied the charging dynamics of insulating foil targets [Mylar, polypropylene (PP)] irradiated with swift ion beams (C, O, Ag, and Xe at 40, 23, 40, and 30 MeV/u, respectively) via the measurement of the slowing down of fast binary-encounter electrons. Also, sandwich targets (Mylar covered with a thin Au layer on both surfaces) and Mylar with Au on only one surface were used. Fast-electron spectra were measured by the time-of-flight method at the superconducting cyclotron of Laboratori Nazionali del Sud (LNS) Catania. The charge buildup leads to target-material-dependent potentials of the order of 6.0 kV for Mylar and 2.8 kV for PP. The sandwich targets, surprisingly, show the same behavior as the insulating targets, whereas a single Au layer on the electron and ion exit side strongly suppresses the charging phenomenon. The accumulated number of projectiles needed for charging up is inversely proportional to electronic energy loss. Thus, the charging up is directly related to emission of secondary electrons.

Charging of insulators by multiply-charged-ion impact probed by slowing down of fast binary-encounter electrons

International Nuclear Information System (INIS)

De Filippo, E.; Lanzano, G.; Cardella, G.; Amorini, F.; Geraci, E.; Grassi, L.; Politi, G.; La Guidara, E.; Lombardo, I.; Rizzo, F.; Russotto, P.; Volant, C.; Hagmann, S.; Rothard, H.

2010-01-01

The interaction of ion beams with insulators leads to charging-up phenomena, which at present are under investigation in connection with guiding phenomena in nanocapillaries with possible application in nanofocused beams. We studied the charging dynamics of insulating foil targets [Mylar, polypropylene (PP)] irradiated with swift ion beams (C, O, Ag, and Xe at 40, 23, 40, and 30 MeV/u, respectively) via the measurement of the slowing down of fast binary-encounter electrons. Also, sandwich targets (Mylar covered with a thin Au layer on both surfaces) and Mylar with Au on only one surface were used. Fast-electron spectra were measured by the time-of-flight method at the superconducting cyclotron of Laboratori Nazionali del Sud (LNS) Catania. The charge buildup leads to target-material-dependent potentials of the order of 6.0 kV for Mylar and 2.8 kV for PP. The sandwich targets, surprisingly, show the same behavior as the insulating targets, whereas a single Au layer on the electron and ion exit side strongly suppresses the charging phenomenon. The accumulated number of projectiles needed for charging up is inversely proportional to electronic energy loss. Thus, the charging up is directly related to emission of secondary electrons.

Gas Gain Measurement Of GEM-Foil In Argon-Carbon Dioxide Mixture

International Nuclear Information System (INIS)

Nguyen Ngoc Duy; Vuong Huu Tan; Le Hong Khiem

2011-01-01

Nuclear reaction measurement with radioactive beam at low energy plays an important role in nuclear astrophysics and nuclear structure. The trajectory of particle beams can be obtained by using an active gas target, multiple-sampling and tracking proportional chamber (MSTPC), as a proportional counter. Because of intensity of low energy radioactive beam, in the stellar reaction such as (α, p), (p, α), it is necessary to increase the gain for the counter. In this case, a gas electrons multiplier (GEM) foil will be used, so the proportional counter is called GEM-MSTPC. The efficient gas gain of GEM foils which relates to foil thickness and operating pressure was investigated with two type of the foils, 400 μm and 200 μm, in Argon (70%) + Carbon dioxide (30%) mixture. (author)

Dosimetric response of united, commercially available CTA foils for sup 6 sup 0 Co gamma rays

CERN Document Server

Peimel-Stuglik, Z

2001-01-01

The usefulness of two kinds of untinted CTA foils: Fuji CTR-125 dosimetric foil and technical CTA-T foil, produced by 'Zaklady Chemiczne, 'Gorzow Wielkopolski' as support for light-sensitive layers of amateur photo-films, for sup 6 sup 0 Co gamma ray dosimetry was investigated. In spite of rather bad physical parameters of the technical foil (spread of foil thickness, high and different initial absorbance) the dosimetric response of both foils for sup 6 sup 0 Co gamma rays was similar. The CTA-T foil can be used for routine dosimetry providing that dosimetric signals have to be calculated exactly as recommended by the ASTM (American Society for Testing and Materials) standard, i.e. as the difference of absorbance of irradiated and (the same) non-irradiated foil. Any other approach may lead to high errors of dose evaluation. The last is true also for other CTA foils, especially after long self-life.

Health status of cows fed maize silage covered with oxo-biodegradable foil

Directory of Open Access Journals (Sweden)

Piotr SZTERK

2017-11-01

Full Text Available In agricultural practice, silage production uses pure, low density polyethylene foil. This foil, after use, becomes farm waste, having a negative impact on the environment. Instead of conventional foil, an environmentally safe biodegradable foil can be used, made from naturally occurring polymers or from synthetic multiparticulates, easily degradable by microorganisms. Silage covered with this type of foil should be safe for animal health. The purpose of the study was to determine whether oxo-biodegradable film could be used instead of conventional film in agricultural practice, to produce silage that is safe for the cows' health. Dairy cows were fed a partly mixed ratio (PMR, the component of which was silage made of whole maize plants, covered with oxo-biodegradable foil. The cow blood serum was marked for content of: glucose, total protein, cholesterol, triacylglycerols and enzyme activity: aspartic and alanine aminotransferase, γ-glutamyl transferase, alkaline phosphatase and amylase. The total protein concentration in the serum of cows analyzed at the end of the experiment was higher than the commonly accepted normal values. The content of glucose, cholesterol, triacylglycerols and the activity of aspartate and alanine aminotransferase, γ-glutamyl transferase, alkaline phosphatase and amylase was within reference limits. Feeding of silage from whole maize plants covered withoxo-biodegradable foil did not negatively affect the biochemical indicators of the cows' blood serum. The silage proved to be safe for the cows' health.

Secondary emission ion analyzer provided with an electron gun for insulating material analysis

International Nuclear Information System (INIS)

Blanchard, Bruno; Carrier, Patrick; Marguerite, J.-L.; Rocco, J.-C.

1976-01-01

This invention relates to a secondary emission ion analyser, fitted with an electron gun. It is used in the mass spectrometry analysis of electrically insulating bodies. It has already been suggested to bombard the target with an electron beam in conjunction with the beam of primary particles, in order to reduce the space charge near the target. The object of this invention is the application of this known process to appliances of the ion analyser type with a high electric field near the target. Its main characteristic is the use of an electron gun emitting an electron beam through the extraction lens placed opposite the target. The extraction electric field influences the path of the electrons but the electric and mechanical specifications of the electron gun in the invention are such that the target is correctly sprayed by the electron beam [fr

Protection against cold in prehospital care-thermal insulation properties of blankets and rescue bags in different wind conditions.

Science.gov (United States)

Henriksson, Otto; Lundgren, J Peter; Kuklane, Kalev; Holmér, Ingvar; Bjornstig, Ulf

2009-01-01

In a cold, wet, or windy environment, cold exposure can be considerable for an injured or ill person. The subsequent autonomous stress response initially will increase circulatory and respiratory demands, and as body core temperature declines, the patient's condition might deteriorate. Therefore, the application of adequate insulation to reduce cold exposure and prevent body core cooling is an important part of prehospital primary care, but recommendations for what should be used in the field mostly depend on tradition and experience, not on scientific evidence. The objective of this study was to evaluate the thermal insulation properties in different wind conditions of 12 different blankets and rescue bags commonly used by prehospital rescue and ambulance services. The thermal manikin and the selected insulation ensembles were setup inside a climatic chamber in accordance to the modified European Standard for assessing requirements of sleeping bags. Fans were adjusted to provide low (value, Itr (m2 C/Wclo; where C = degrees Celcius, and W = watts), was calculated from ambient air temperature (C), manikin surface temperature (C), and heat flux (W/m2). In the low wind condition, thermal insulation of the evaluated ensembles correlated to thickness of the ensembles, ranging from 2.0 to 6.0 clo (1 clo = 0.155 m2 C/W), except for the reflective metallic foil blankets that had higher values than expected. In moderate and high wind conditions, thermal insulation was best preserved for ensembles that were windproof and resistant to the compressive effect of the wind, with insulation reductions down to about 60-80% of the original insulation capacity, whereas wind permeable and/or lighter materials were reduced down to about 30-50% of original insulation capacity. The evaluated insulation ensembles might all be used for prehospital protection against cold, either as single blankets or in multiple layer combinations, depending on ambient temperatures. However, with extended

Magazine for handling stripping foils in a particle accelerator

International Nuclear Information System (INIS)

Gorka, A.J. Jr.

1975-01-01

Thin foils for stripping a particle beam are stored in a magazine that is operable remotely to display an individual foil, release it when it is spent, and repeat this process. The magazine is operable in the high-vacuum, high-radiation environment in the interior of a particle accelerator, and it uses the magnetic field of the accelerator to operate the display and dropping mechanism. (U.S.)

X-ray scattering measurements from thin-foil x-ray mirrors

DEFF Research Database (Denmark)

Christensen, Finn Erland; BYRNAK, BP; Hornstrup, Allan

1992-01-01

Thin foil X-ray mirrors are to be used as the reflecting elements in the telescopes of the X-ray satellites Spectrum-X-Gamma (SRG) and ASTRO-D. High resolution X-ray scattering measurements from the Au coated and dip-lacquered Al foils are presented. These were obtained from SRG mirrors positioned...... in a test quadrant of the telescope structure and from ASTRO-D foils held in a simple fixture. The X-ray data is compared with laser data and other surface structure data such as STM, atomic force microscopy (AFM), TEM, and electron micrography. The data obtained at Cu K-alpha(1), (8.05 keV) from all...

Irradiation tests of 99Mo isotope production targets employing uranium metal foils

International Nuclear Information System (INIS)

Hofman, G.L.; Wiencek, T.C.; Wood, E.L.; Snelgrove, J.L.; Suripto, A.; Nasution, H.; Lufti-Amin, D.; Gogo, A.

1996-01-01

Most of the world's supply of 99 mTc for medical purposes is currently produced from the decay of 99 Mo derived from the fissioning of high-enriched uranium (HEU). Substitution of low-enriched uranium (LEU) metal foils for the HEU UO 2 used in current target designs will allow equivalent 99 Mo yields with little change in target geometries. Substitution of uranium metal for uranium alloy and aluminide in other target designs will also allow the conversion of HEU to LEU. Several uranium-metal-foil targets have been fabricated at ANL and irradiated to prototypic burnup in the Indonesian RSG-GAS reactor. Postirradiation examination of the initial test indicated that design modifications were required to allow the irradiated foil to be removed for chemical processing. The latest test has shown good irradiation behavior, satisfactory dismantling and foil removal when the U-foil is separated from its containment by metallic, fission-recoil absorbing barriers. (author)

Irradiation tests of 99Mo isotope production targets employing uranium metal foils

International Nuclear Information System (INIS)

Hofman, G.L.; Wiencek, T.C.; Wood, E.L.; Snelgrove, J.L.; Suripto, A.; Nasution, H.; Lufti-Amin, D.; Gogo, A.

1996-01-01

Most of the world's supply of 99m Tc for medical purposes is currently produced form the decay of 99 Mo derived from the fissioning of high-enriched uranium (HEU). Substitution of low-enriched uranium (LEU) metal foils for the HEU UO 2 used in current target designs will allow equivalent 99 Mo yields with little change in target geometries. Substitution of uranium metal for uranium alloy and aluminide in other target designs will also allow the conversion of HEU to LEU. Several uranium-metal-foil targets have been fabricated at ANL and irradiated to prototypic burnup in the Indonesian RSG-GAS reactor. Postirradiation examination of the initial test indicated that design modifications were required to allow the irradiated foil to be removed for chemical processing. The latest test has shown good irradiation behavior, satisfactory dismantling and foil removal when the U-foil is separated from its containment by metallic, fission-recoil absorbing barriers

Personnel neutron dosimetry applications of track-size distributions on electrochemically etched CR-39 foils

International Nuclear Information System (INIS)

Hankins, D.E.; Homann, S.G.; Westermark, J.

1988-01-01

The track-size distribution on electrochemically etched CR-39 foils can be used to obtain some limited information on the incident neutron spectra. Track-size distributions on CR-39 foils can also be used to determine if the tracks were caused by neutrons or if they are merely background tracks (which have a significantly different track-size distribution). Identifying and discarding the high-background foils reduces the number of foils that must be etched. This also lowers the detection limit of the dosimetry system. We have developed an image analyzer program that can more efficiently determine the track density and track-size distribution, as well as read the laser-cut identification numbers on each foil. This new image analyzer makes the routine application of track-size distributions on CR-39 foils feasible. 2 refs., 3 figs

Highly sensitive urea sensing with ion-irradiated polymer foils

International Nuclear Information System (INIS)

Fink, Dietmar; Muñoz Hernandez, Gerardo; Alfonta, Lital

2012-01-01

Recently we prepared urea-sensors by attaching urease to the inner walls of etched ion tracks within thin polymer foil. Here, alternative track-based sensor configurations are examined where the enzyme remained in solution. The conductivities of systems consisting of two parallel irradiated polymer foils and confining different urea/urease mixtures in between were examined. The correlations between conductivity and urea concentration differed strongly for foils with unetched and etched tracks, which points at different sensing mechanisms – tentatively attributed to the adsorption of enzymatic reaction products on the latent track entrances and to the enhanced conductivity of reaction product-filled etched tracks, respectively. All examined systems enable in principle, urea sensing. They point at the possibility of sensor cascade construction for more sensitive or selective sensor systems.

Foil Strain Gauges Using Piezoresistive Carbon Nanotube Yarn: Fabrication and Calibration

Directory of Open Access Journals (Sweden)

Jandro L. Abot

2018-02-01

Full Text Available Carbon nanotube yarns are micron-scale fibers comprised by tens of thousands of carbon nanotubes in their cross section and exhibiting piezoresistive characteristics that can be tapped to sense strain. This paper presents the details of novel foil strain gauge sensor configurations comprising carbon nanotube yarn as the piezoresistive sensing element. The foil strain gauge sensors are designed using the results of parametric studies that maximize the sensitivity of the sensors to mechanical loading. The fabrication details of the strain gauge sensors that exhibit the highest sensitivity, based on the modeling results, are described including the materials and procedures used in the first prototypes. Details of the calibration of the foil strain gauge sensors are also provided and discussed in the context of their electromechanical characterization when bonded to metallic specimens. This characterization included studying their response under monotonic and cyclic mechanical loading. It was shown that these foil strain gauge sensors comprising carbon nanotube yarn are sensitive enough to capture strain and can replicate the loading and unloading cycles. It was also observed that the loading rate affects their piezoresistive response and that the gauge factors were all above one order of magnitude higher than those of typical metallic foil strain gauges. Based on these calibration results on the initial sensor configurations, new foil strain gauge configurations will be designed and fabricated, to increase the strain gauge factors even more.

Foil Strain Gauges Using Piezoresistive Carbon Nanotube Yarn: Fabrication and Calibration

Science.gov (United States)

Góngora-Rubio, Mário R.; Kiyono, César Y.; Mello, Luis A. M.; Cardoso, Valtemar F.; Rosa, Reinaldo L. S.; Kuebler, Derek A.; Brodeur, Grace E.; Alotaibi, Amani H.; Coene, Marisa P.; Coene, Lauren M.; Jean, Elizabeth; Santiago, Rafael C.; Oliveira, Francisco H. A.; Rangel, Ricardo; Thomas, Gilles P.; Belay, Kalayu; da Silva, Luciana W.; Moura, Rafael T.; Seabra, Antonio C.; Silva, Emílio C. N.

2018-01-01

Carbon nanotube yarns are micron-scale fibers comprised by tens of thousands of carbon nanotubes in their cross section and exhibiting piezoresistive characteristics that can be tapped to sense strain. This paper presents the details of novel foil strain gauge sensor configurations comprising carbon nanotube yarn as the piezoresistive sensing element. The foil strain gauge sensors are designed using the results of parametric studies that maximize the sensitivity of the sensors to mechanical loading. The fabrication details of the strain gauge sensors that exhibit the highest sensitivity, based on the modeling results, are described including the materials and procedures used in the first prototypes. Details of the calibration of the foil strain gauge sensors are also provided and discussed in the context of their electromechanical characterization when bonded to metallic specimens. This characterization included studying their response under monotonic and cyclic mechanical loading. It was shown that these foil strain gauge sensors comprising carbon nanotube yarn are sensitive enough to capture strain and can replicate the loading and unloading cycles. It was also observed that the loading rate affects their piezoresistive response and that the gauge factors were all above one order of magnitude higher than those of typical metallic foil strain gauges. Based on these calibration results on the initial sensor configurations, new foil strain gauge configurations will be designed and fabricated, to increase the strain gauge factors even more. PMID:29401745

Monte Carlo simulation of positron induced secondary electrons in thin carbon foils

International Nuclear Information System (INIS)

Cai, L H; Yang, B; Ling, C C; Beling, C D; Fung, S

2011-01-01

Emission of secondary electrons induced by the passage of low energy positrons through thin carbon foils was studied by the Monte Carlo method. The positron and electron elastic cross sections were calculated by partial wave analysis. The inelastic positron-valence-electron was described by the energy loss function obtained from dielectric theory. The positron-core-electron interaction was modelled by the Gryzinski's excitation function. Positron transport inside the carbon foil was simulated in detail. Secondary electrons created by positrons and high energy secondary electrons through inelastic interactions were tracked through the foil. The positron transmission coefficient and secondary electron yielded in forward and backward geometry are calculated and dependences on positron energy and carbon foil thickness are discussed.

Intense heavy ion beam-induced temperature effects in carbon-based stripper foils

International Nuclear Information System (INIS)

Kupka, K.; Tomut, M.; Simon, P.; Hubert, C.; Romanenko, A.; Lommel, B.; Trautmann, C.

2015-01-01

At the future FAIR facility, reliably working solid carbon stripper foils are desired for providing intermediate charge states to SIS18. With the expected high beam intensities, the foils experience enhanced degradation and limited lifetime due to severe radiation damage, stress waves, and thermal effects. This work presents systematic measurements of the temperature of different carbon-based stripper foils (amorphous, diamond-like, and carbon-nanotube based) exposed to 4.8 MeV/u U, Bi, and Au beams of different pulse intensities. Thermal and spectroscopic analyses were performed by means of infrared thermography and Fourier transform infrared spectroscopy. The resulting temperature depends on the foil thickness and strongly increases with increasing pulse intensity and repetition rate. (author)

MD and BCA simulations of He and H bombardment of fuzz in bcc elements

Science.gov (United States)

Klaver, T. P. C.; Zhang, S.; Nordlund, K.

2017-08-01

We present results of MD simulations of low energy He ion bombardment of low density fuzz in bcc elements. He ions can penetrate several micrometers into sparse fuzz, which allows for a sufficient He flux through it to grow the fuzz further. He kinetic energy falls off exponentially with penetration depth. A BCA code was used to carry out the same ion bombardment on the same fuzz structures as in MD simulations, but with simpler, 10 million times faster calculations. Despite the poor theoretical basis of the BCA at low ion energies, and the use of somewhat different potentials in MD and BCA calculations, the ion penetration depths predicted by BCA are only ∼12% less than those predicted by MD. The MD-BCA differences are highly systematic and trends in the results of the two methods are very similar. We have carried out more than 200 BCA calculation runs of ion bombardment of fuzz, in which parameters in the ion bombardment process were varied. For most parameters, the results show that the ion bombardment process is quite generic. The ion species (He or H), ion mass, fuzz element (W, Ta, Mo, Fe) and fuzz element lattice parameter turned out to have a modest influence on ion penetration depths at most. An off-normal angle of incidence strongly reduces the ion penetration depth. Increasing the ion energy increases the ion penetration, but the rate by which ion energy drops off at high ion energies follows the same exponential pattern as at lower energies.

Transient and steady state behaviour of elasto–aerodynamic air foil bearings, considering bump foil compliance and top foil inertia and flexibility: A numerical investigation

DEFF Research Database (Denmark)

Nielsen, Bo Bjerregaard; Santos, Ilmar F.

2017-01-01

utilise two types of eight-node isoparametric elements. The rotor is modelled as a rigid body without rotational inertia, i.e. as a journal. The bump foil is included via a bilinear version of the simple elastic foundation model. This paper introduces the bilinear simple elastic foundation model, which...

Stripper foil failure modes and cures at the Oak Ridge Spallation Neutron Source

Directory of Open Access Journals (Sweden)

M. A. Plum

2011-03-01

Full Text Available The Oak Ridge Spallation Neutron Source comprises a 1 GeV, 1.5 MW linear accelerator followed by an accumulator ring and a liquid mercury target. To manage the beam loss caused by the H^{0} excited states created during the H^{-} charge-exchange injection into the accumulator ring, the stripper foil is located inside one of the chicane dipoles. This has some interesting consequences that were not fully appreciated until the beam power reached about 840 kW. One consequence was sudden failure of the stripper foil system due to convoy electrons stripped from the incoming H^{-} beam, which circled around to strike the foil bracket and cause bracket failure. Another consequence is that convoy electrons can reflect back up from the electron catcher and strike the foil and bracket. An additional contributor to foil system failure is vacuum breakdown due to the charge developed on the foil by secondary electron emission. In this paper we detail these and other interesting failure mechanisms and describe the improvements we have made to mitigate them.

Brazing Inconel 625 Using the Copper Foil

Science.gov (United States)

Chen, Wen-Shiang; Wang, Cheng-Yen; Shiue, Ren-Kae

2013-12-01

Brazing Inconel 625 (IN-625) using the copper foil has been investigated in this research. The brazed joint is composed of nanosized CrNi3 precipitates and Cr/Mo/Nb/Ni quaternary compound in the Cu/Ni-rich matrix. The copper filler 50 μm in thickness is enough for the joint filling. However, the application of Cu foil 100 μm in thickness has little effect on the shear strength of the brazed joint. The specimen brazed at 1433 K (1160 °C) for 1800 seconds demonstrates the best shear strength of 470 MPa, and its fractograph is dominated by ductile dimple fracture with sliding marks. Decreasing the brazing temperature slightly decreases the shear strength of the brazed joint due to the presence of a few isolated solidification shrinkage voids smaller than 15 μm. Increasing the brazing temperature, especially for the specimen brazed at 1473 K (1200 °C), significantly deteriorates the shear strength of the joint below 260 MPa because of coalescence of isothermal solidification shrinkage voids in the joint. The Cu foil demonstrates potential in brazing IN-625 for industrial application.

Transmission of fast molecular ions through thin foils

International Nuclear Information System (INIS)

Pietsch, W.J.; Gemmell, D.S.; Cooney, P.J.; Kanter, E.P.; Kurath, D.; Ratkowski, A.J.; Vager, Z.; Zabransky, B.J.

1979-01-01

New results on the transmission of fast molecular ions through thin foils are presented and a mechanism for the transmission process is proposed. The main feature of the postulated mechanism is that a finite fraction of the incident molecular beam does not undergo a strong Coulomb explosion while traversing the foil. Because the emerging fragments are at large internuclear separations, there is an enhanced probability for the formation of bound, long-range, excited electronic states following electron capture at the rear surface of the target

Ion bombardment effects on surface states in selected oxide systems: rutile and alkaline earth titanates

International Nuclear Information System (INIS)

Gruen, D.M.

1978-01-01

In this paper, the nature of the surface states of n-type TiO 2 and SrTiO 3 is discussed and the role of ion bombardment in modifying the properties of these states is elucidated. Insofar as possible, the interrelationships between oxide nonstoichiometry, surface states, ion bombardment effects and photoelectrolysis are explored

75 FR 1596 - Grant of Authority for Subzone Status, Reynolds Packaging LLC (Aluminum Foil Liner Stock...

Science.gov (United States)

2010-01-12

... Status, Reynolds Packaging LLC (Aluminum Foil Liner Stock), Louisville, Kentucky Pursuant to its...-purpose subzone at the aluminum foil liner stock manufacturing and distribution facilities of Reynolds... manufacturing and distribution of aluminum foil liner stock and aluminum foil at the facilities of Reynolds...

Theoretical simulations of atomic and polyatomic bombardment of an organic overlayer on a metallic substrate

CERN Document Server

Krantzman, K D; Delcorte, A; Garrison, B J

2003-01-01

Our previous molecular dynamics simulations on initial test systems have laid the foundation for understanding some of the effects of polyatomic bombardment. In this paper, we describe simulations of the bombardment of a more realistic model system, an overlayer of sec-butyl-terminated polystyrene tetramers on a Ag left brace 1 1 1 right brace substrate. We have used this model system to study the bombardment with Xe and SF sub 5 projectiles at kinetic energies ranging from 0.50 to 5.0 keV. SF sub 5 sputters more molecules than Xe, but a higher percentage of these are damaged rather than ejected intact when the bombarding energy is greater than 0.50 keV. Therefore, at energies comparable to experimental values, the efficiency, measured as the yield-to-damage ratio, is greater with Xe than SF sub 5. Stable and intact molecules are generally produced by upward moving substrate atoms, while fragments are produced by the upward and lateral motion of reflected projectile atoms and fragments from the target molecul...

Effects of ion beam bombardment of carbon thin films deposited onto tungsten carbide and tool steels

Energy Technology Data Exchange (ETDEWEB)

Awazu, Kaoru; Yoshida, Hiroyuki [Industrial Research Inst. of Ishikawa (Japan); Watanabe, Hiroshi [Gakushuin Univ., Tokyo (Japan); Iwaki, Masaya; Guzman, L [RIKEN, Saitama (Japan)

1992-04-15

A study was made of the effects of argon ion bombardment of carbon thin films deposited onto WC and tool steels. Carbon thin film deposition was performed at various temperatures ranging from 200degC to 350degC, using C{sub 6}H{sub 6} gas. Argon ion beam bombardment of the films was carried out at an energy of 150 keV with a dose of 1x10{sup 16} ions cm{sup -2}. The hardness and adhesion of the films were measured by means of Knoop hardness and scratch tests respectively. The structure of the carbon films was estimated by laser Raman spectroscopy, and the relations were investigated between the mechanical properties and the structure of the films. The hardness of carbon thin films increases as their deposition temperature decreases; this tendency corresponds to the increase in amorphous structure estimated by Raman spectra. Argon ion bombardment results in constant hardness and fraction of amorphous structure. Argon ion beam bombardment of films prior to additional carbon deposition may cause the adhesion of the subsequently deposited films to improve. It is concluded that argon ion beam bombardment is useful for improving the properties of carbon films deposited onto WC and tool steels. (orig.).

Effects of ion beam bombardment of carbon thin films deposited onto tungsten carbide and tool steels

International Nuclear Information System (INIS)

Awazu, Kaoru; Yoshida, Hiroyuki; Watanabe, Hiroshi; Iwaki, Masaya; Guzman, L.

1992-01-01

A study was made of the effects of argon ion bombardment of carbon thin films deposited onto WC and tool steels. Carbon thin film deposition was performed at various temperatures ranging from 200degC to 350degC, using C 6 H 6 gas. Argon ion beam bombardment of the films was carried out at an energy of 150 keV with a dose of 1x10 16 ions cm -2 . The hardness and adhesion of the films were measured by means of Knoop hardness and scratch tests respectively. The structure of the carbon films was estimated by laser Raman spectroscopy, and the relations were investigated between the mechanical properties and the structure of the films. The hardness of carbon thin films increases as their deposition temperature decreases; this tendency corresponds to the increase in amorphous structure estimated by Raman spectra. Argon ion bombardment results in constant hardness and fraction of amorphous structure. Argon ion beam bombardment of films prior to additional carbon deposition may cause the adhesion of the subsequently deposited films to improve. It is concluded that argon ion beam bombardment is useful for improving the properties of carbon films deposited onto WC and tool steels. (orig.)

Confirming the key role of Ar+ ion bombardment in the growth feature of nanostructured carbon materials by PECVD

Science.gov (United States)

Liu, Yulin; Lin, Jinghuang; Jia, Henan; Chen, Shulin; Qi, Junlei; Qu, Chaoqun; Cao, Jian; Feng, Jicai; Fei, Weidong

2017-11-01

In order to confirm the key role of Ar+ ion bombardment in the growth feature of nanostructured carbon materials (NCMs), here we report a novel strategy to create different Ar+ ion states in situ in plasma enhanced chemical vapor deposition (PECVD) by separating catalyst film from the substrate. Different bombardment environments on either side of the catalyst film were created simultaneously to achieve multi-layered structural NCMs. Results showed that Ar+ ion bombardment is crucial and complex for the growth of NCMs. Firstly, Ar+ ion bombardment has both positive and negative effects on carbon nanotubes (CNTs). On one hand, Ar+ ions can break up the graphic structure of CNTs and suppress thin CNT nucleation and growth. On the other hand, Ar+ ion bombardment can remove redundant carbon layers on the surface of large catalyst particles which is essential for thick CNTs. As a result, the diameter of the CNTs depends on the Ar+ ion state. As for vertically oriented few-layer graphene (VFG), Ar+ ions are essential and can even convert the CNTs into VFG. Therefore, by combining with the catalyst separation method, specific or multi-layered structural NCMs can be obtained by PECVD only by changing the intensity of Ar+ ion bombardment, and these special NCMs are promising in many fields.

Confirming the key role of Ar+ ion bombardment in the growth feature of nanostructured carbon materials by PECVD.

Science.gov (United States)

Liu, Yulin; Lin, Jinghuang; Jia, Henan; Chen, Shulin; Qi, Junlei; Qu, Chaoqun; Cao, Jian; Feng, Jicai; Fei, Weidong

2017-11-24

In order to confirm the key role of Ar + ion bombardment in the growth feature of nanostructured carbon materials (NCMs), here we report a novel strategy to create different Ar + ion states in situ in plasma enhanced chemical vapor deposition (PECVD) by separating catalyst film from the substrate. Different bombardment environments on either side of the catalyst film were created simultaneously to achieve multi-layered structural NCMs. Results showed that Ar + ion bombardment is crucial and complex for the growth of NCMs. Firstly, Ar + ion bombardment has both positive and negative effects on carbon nanotubes (CNTs). On one hand, Ar + ions can break up the graphic structure of CNTs and suppress thin CNT nucleation and growth. On the other hand, Ar + ion bombardment can remove redundant carbon layers on the surface of large catalyst particles which is essential for thick CNTs. As a result, the diameter of the CNTs depends on the Ar + ion state. As for vertically oriented few-layer graphene (VFG), Ar + ions are essential and can even convert the CNTs into VFG. Therefore, by combining with the catalyst separation method, specific or multi-layered structural NCMs can be obtained by PECVD only by changing the intensity of Ar + ion bombardment, and these special NCMs are promising in many fields.

Visualization and Measurement of the Deflagration of JA2 Bonded to Various Metal Foils

Science.gov (United States)

2016-01-01

foil. Tapes had an acrylic -adhesive backing applied by the manufacturer. The conductive material, whether foil or tape, ran approximately ¾ the...event were obtained such that the 0.5-inch surface was facing the camera with the foil on the right edge. The thicknesses and tape/foil configuration...adhesive type, there were differences. A 2-mil Al tape was obtained from McMaster-Carr (product No. 7925A1). It had a 2- mil-thick acrylic adhesive

Alteration of the UV-visible reflectance spectra of H2O ice by ion bombardment

Science.gov (United States)

Sack, N. J.; Boring, J. W.; Johnson, R. E.; Baragiola, R. A.; Shi, M.

1991-01-01

Satellite in the Jovian and Saturnian system exhibit differences in reflectivity between their 'leading' and 'trailing' surfaces which can affect the local vapor pressure. Since these differences are thought to be due to differences in the flux of bombarding magnetospheric ions, the influence of ion impact on the UV-visible reflectance of water ice surfaces (20-90 K) by keV ion bombardment was studied. An observed decrease in reflectance in the UV is attributed to rearrangement processes that affect the physical microstructure and surface 'roughness'. The ratio in reflectance of bombarded to freshly deposited films is compared to the ratio of the reflectance of the leading and trailing hemispheres for Europa and Ganymede.

Facies of ion bombarded surfaces of brittle materials

International Nuclear Information System (INIS)

Primak, W.

1975-12-01

Materials were bombarded by protons, deuterons, and helium ions. The materials investigated were quartz; glasses; carbides and borides (SiC, B 4 C, TiB 2 ); oxides and nitrides (magnorite, sapphire, spinel, Al 2 O 3 , Si 3 N 4 , ZrO 2 , BaTiO 3 ); and miscellaneous (graphite, LiNbO 3 , copper). Oberservations were of growth, reflectivity, blistering, surface ablation, and swelling. Calculations were made of the effects of a layer, of its gradual transformation, and of the introduction of a gas. It is concluded that: Radiation blistering is not a primary process. Observations of blister formation and exfoliation cannot be used to calculate the surface ablation rate. The primary process is the development of a microporous layer which causes swelling. Visible blisters are caused by fracturing by transverse stresses in this layer and may occur during the bombardment, or in some cases, much later, in storage. There is no evidence of extreme gas pressures in the blisters. When blisters develop, they may be stable under continued bombardment for a dose many times that at which they formed. The swelling is a better index of the effects than is the blistering, and must be associated in most cases with permeability to the gas. Behavior with protons and deuterons is similar, with helium different. All but quartz, vitreous silica, and Pyrex are impervious to hydrogen and deuterium; only dense barium crown glass, carbides, borides, oxides, and nitrides are impervious to helium. Quartz shows swelling caused by conversion to a vitreous product of much lower density but no porosity, while for the others, most of the swelling and surface growth is caused by porosity. Surface ablation by the blistering process may be reduced by initial porosity or by initial or subsequent surface fissuring. However, for impervious materials, surface damage by the introduction of porosity would continue

Direct thermal effects of the Hadean bombardment did not limit early subsurface habitability

Science.gov (United States)

Grimm, R. E.; Marchi, S.

2018-03-01

Intense bombardment is considered characteristic of the Hadean and early Archean eons, yet some detrital zircons indicate that near-surface water was present and thus at least intervals of clement conditions may have existed. We investigate the habitability of the top few kilometers of the subsurface by updating a prior approach to thermal evolution of the crust due to impact heating, using a revised bombardment history, a more accurate thermal model, and treatment of melt sheets from large projectiles (>100 km diameter). We find that subsurface habitable volume grows nearly continuously throughout the Hadean and early Archean (4.5-3.5 Ga) because impact heat is dissipated rapidly compared to the total duration and waning strength of the bombardment. Global sterilization was only achieved using an order of magnitude more projectiles in 1/10 the time. Melt sheets from large projectiles can completely resurface the Earth several times prior to ∼4.2 Ga but at most once since then. Even in the Hadean, melt sheets have little effect on habitability because cooling times are short compared to resurfacing intervals, allowing subsurface biospheres to be locally re-established by groundwater infiltration between major impacts. Therefore the subsurface is always habitable somewhere, and production of global steam or silicate-vapor atmospheres are the only remaining avenues to early surface sterilization by bombardment.

Flexible, durable proton energy degraders for the GE PETtrace

DEFF Research Database (Denmark)

Engle, J. W.; Gagnon, K.; Severin, Gregory

2012-01-01

In order to limit the formation of radioisotopic impurities during proton bombardments of solid targets, two methods of introducing degrader foils into the beam upstream of the target were tested. The first design uses a 445 μm thick fixed degrader machined from a single piece of aluminum....... The second design permits introduction of foils made of any material and was tested with foils as thick as 635 μm (also aluminium). In both cases, the foils are cooled with by water flowing through an annular channel outside the radius of the beam. Both designs proved durable and tolerated proton beam...

Saving millions by thermal insulation; Miljoenen besparen door goede isolatie

Energy Technology Data Exchange (ETDEWEB)

Van der Velden, U. [Nederlands Centrum voor Technische Isolatie NCTI, spijkenisse (Netherlands)

2009-07-15

Corrosion under insulation (CUI) can be reduced by the application of a correctly designed, installed and maintained insulation system. In refrigeration plants a heat flow will occur from the warm outside towards the cold inside. Hot air, containing more moisture, will be distributed to the cold components of the installation, such as separators, intermediate coolers, piping and valves, thus not only facilitating CUI, but also seriously compromising the thermal performance of the system. Furthermore, this moisture could condensate or freeze and compromise the integrity of the installation. Insulation in cold systems is built up with closed cell materials, such as elastomeric foam, PIR (polyisocyanurate) or cellular glass. On the outside a vapor barrier (e.g. reinforced aluminium foil) is essential to prevent hot moist air from penetrating the system. For protection against weather influences and/or mechanical damage, the system should be finished with a (non)metal cladding. [Dutch] Corrosie onder isolatie (CUI) kan worden beperkt door toepassing van een correct ontworpen, geinstalleerd en onderhouden isolatiesysteem. Bij koude-isolatiesystemen treedt een warmtestroom van buiten naar binnen op. Warme lucht - die meer vocht bevat - dringt naar installatiecomponenten, zoals afscheiders, tussenkoelers, leidingen en afstuiters, waarbij niet alleen het risico op CUI aanzienlijk toeneemt, maar ook de isolatiewaarde van het systeem gereduceerd wordt. Vocht kan hierbij ook nog condenseren of bevriezen en de integriteit van de hele installatie in gevaar brengen. Koude-isolatiesystemen dienen te worden opgebouwd met gesloten cel-materiaal, zoals elastomeer schuim, PIR (polyisocyanurate) of cellulair glas. Het systeem dient aan de buitenzijde te worden voorzien van een dampremmende laag (van bijvoorbeeld versterkt aluminiumfolie) om binnendringend vocht te blokkeren. In buitencondities moet het systeem worden voorzien van een (metalen of niet-metalen) eindafwerking, die

Effects of the Addictives on Etching Characteristics of Aluminum Foil

Energy Technology Data Exchange (ETDEWEB)

Kim, S.K.; Jang, J.M.; Chi, C.S. [Kookmin University, Seoul (Korea); Shin, D.C. [Sungnam Polytechnic, Sungnam (Korea); Lee, J.H.; Oh, H.J. [Hanseo University, Seosan (Korea)

2001-01-01

The effects of additives in the HCI etching solution on etching behaviors of aluminium foil as dielectric film for electrolytic capacitors were investigated. The etch pits formed in 1M hydrochloric acid containing ethylene glycol as an additive contain more fine and homogeneous etch tunnels compared to thoese in 1 M hydrochloric acid only, which led to the increase in the effective internal surface area of aluminum foil. After anodizing of aluminum foil etched in etching solutions, the LCR meter results have shown that the capacitance of dielectric film etched in hydrochloric acid with ethylene glycol was increased remarkably compared to that etched in hydrochloric acid only. (author). 21 refs., 10 figs.

Slowing down of 100 keV antiprotons in Al foils

Science.gov (United States)

Nordlund, K.

2018-03-01

Using energy degrading foils to slow down antiprotons is of interest for producing antihydrogen atoms. I consider here the slowing down of 100 keV antiprotons, that will be produced in the ELENA storage ring under construction at CERN, to energies below 10 keV. At these low energies, they are suitable for efficient antihydrogen production. I simulate the antihydrogen motion and slowing down in Al foils using a recently developed molecular dynamics approach. The results show that the optimal Al foil thickness for slowing down the antiprotons to below 5 keV is 910 nm, and to below 10 keV is 840 nm. Also the lateral spreading of the transmitted antiprotons is reported and the uncertainties discussed.

Foil bearing performance in liquid nitrogen and liquid oxygen

Science.gov (United States)

Genge, Gary G.; Saville, Marshall; Gu, Alston

1993-01-01

Space transfer vehicles and other power and propulsion systems require long-life turbopumps. Rolling-element bearings used in current turbopumps do not have sufficient life for these applications. Process fluid foil bearings have established long life, with exceptional reliability, over a wide range of temperatures and fluids in many high-speed turbomachinery applications. However, actual data on bearing performance in cryogenic fluids has been minimal. The National Aeronautics and Space Administration (NASA) and AlliedSignal Aerospace Systems and Equipment (ASE) have attempted to characterize the leaf-type compliant foil bearing in oxygen and nitrogen. The work performed under a joint internal research and development program between Marshall Space Flight Center (MSFC) and ASE demonstrated that the foil bearing has load capacities of at least 266 psi in liquid oxygen and 352 psi in liquid nitrogen. In addition, the bearing demonstrated a direct damping coefficient of 40 to 50 lb-sec/in. with a damping ratio of .7 to 1.4 in. liquid nitrogen using a bearing sized for upper-stage turbopumps. With the results from this testing and the years of successful use in air cycle machines and other applications, leaf-type compliant foil bearings are ready for testing in liquid oxygen turbopumps.

Flexible supercapacitor electrodes with vertically aligned carbon nanotubes grown on aluminum foils

Directory of Open Access Journals (Sweden)

Itir Bakis Dogru

2016-06-01

Full Text Available In this work, vertically aligned carbon nanotubes (VACNTs grown on aluminum foils were used as flexible supercapacitor electrodes. Aluminum foils were used as readily available, cheap and conductive substrates, and VACNTs were grown directly on these foils through chemical vapor deposition (CVD method. Solution based ultrasonic spray pyrolysis (USP method was used for the deposition of the CNT catalyst. Direct growth of VACNTs on aluminum foils ruled out both the internal resistance of the supercapacitor electrodes and the charge transfer resistance between the electrode and electrolyte. A specific capacitance of 2.61 mF/cm2 at a scan rate of 800 mV/s was obtained from the fabricated electrodes, which is further improved through the bending cycles.

Compliant Foil Journal Bearings - Investigation of Dynamic Properties

DEFF Research Database (Denmark)

Larsen, Jon Steffen; Santos, Ilmar

. The influence of explicit and implicit boundary conditions are also investigated. Theoretical results for pressures, shaft equilibrium positions and film thickness are presented and compared to experimental results [17, 19]. A good agreement between experimental and theoretical results are found for large loads....../compliance of the foil structure is presented. The compliance of the foil structure is incorporated implicitly in the Reynolds equation which is accomplished through a modification of the film gap function [8]. The resulting non-linear equation is perturbed and solved by use of the finite element method following...

Real-time simulator for designing electron dual scattering foil systems.

Science.gov (United States)

Carver, Robert L; Hogstrom, Kenneth R; Price, Michael J; LeBlanc, Justin D; Pitcher, Garrett M

2014-11-08

The purpose of this work was to develop a user friendly, accurate, real-time com- puter simulator to facilitate the design of dual foil scattering systems for electron beams on radiotherapy accelerators. The simulator allows for a relatively quick, initial design that can be refined and verified with subsequent Monte Carlo (MC) calculations and measurements. The simulator also is a powerful educational tool. The simulator consists of an analytical algorithm for calculating electron fluence and X-ray dose and a graphical user interface (GUI) C++ program. The algorithm predicts electron fluence using Fermi-Eyges multiple Coulomb scattering theory with the reduced Gaussian formalism for scattering powers. The simulator also estimates central-axis and off-axis X-ray dose arising from the dual foil system. Once the geometry of the accelerator is specified, the simulator allows the user to continuously vary primary scattering foil material and thickness, secondary scat- tering foil material and Gaussian shape (thickness and sigma), and beam energy. The off-axis electron relative fluence or total dose profile and central-axis X-ray dose contamination are computed and displayed in real time. The simulator was validated by comparison of off-axis electron relative fluence and X-ray percent dose profiles with those calculated using EGSnrc MC. Over the energy range 7-20 MeV, using present foils on an Elekta radiotherapy accelerator, the simulator was able to reproduce MC profiles to within 2% out to 20 cm from the central axis. The central-axis X-ray percent dose predictions matched measured data to within 0.5%. The calculation time was approximately 100 ms using a single Intel 2.93 GHz processor, which allows for real-time variation of foil geometrical parameters using slider bars. This work demonstrates how the user-friendly GUI and real-time nature of the simulator make it an effective educational tool for gaining a better understanding of the effects that various system

Study on evolution of gases from fluoropolymer films bombarded with heavy ions

International Nuclear Information System (INIS)

Minamisawa, Renato Amaral; Zimmerman, Robert Lee; Budak, Satilmis; Ila, Daryush

2008-01-01

Ion beam bombardment provides a unique way of material modification by inducing a high degree of localized electronic excitation. The ion track, or affected volume along the ion path through the material is related to the total damage and possible structural changes. Here we study the evolution of gases emitted by poly(tetrafluorethylene-co-perfluoro-(propyl vinyl ether)) (PFA) fluoropolymer bombarded with MeV gold ions. The gas was monitored by a residual gas analyzer (RGA), as a function of the ion fluence. Micro-Raman, atomic force microscopy and optical absorption were used to analyze the chemical structure changes and sputtering yield

Thermal performance measurements of a 100 percent polyester MLI [multilayer insulation] system for the Superconducting Super Collider

International Nuclear Information System (INIS)

Boroski, W.N.; Gonczy, J.D.; Niemann, R.C.

1989-09-01

Thermal performance measurements of a 100 percent polyester multilayer insulation (MLI) system for the Superconducting Super Collider (SSC) were conducted in a Heat Leak Test Facility (HLTF) under three experimental test arrangements. Each experiment measured the thermal performance of a 32-layer MLI blanket instrumented with twenty foil sensors to measure interstitial layer temperatures. Heat leak values and sensor temperatures were monitored during transient and steady state conditions under both design and degraded insulating vacuums. Heat leak values were measured using a heatmeter. MLI interstitial layer temperatures were measured using Cryogenic Linear Temperature Sensors (CLTS). Platinum resistors monitored system temperatures. High vacuum was measured using ion gauges; degraded vacuum employed thermocouple gauges. A four-wire system monitored instrumentation sensors and calibration heaters. An on-line computerized data acquisition system recorded and processes data. This paper reports on the instrumentation and experimental preparation used in carrying out these measurements. In complement with this paper is an associate paper bearing the same title head, but with the title extension 'Part 2: Laboratory results (300K--80K). 13 refs., 7 figs

Spectroscopic Measurements of Planar Foil Plasmas Driven by a MA LTD

Science.gov (United States)

Patel, Sonal; Yager-Elorriaga, David; Steiner, Adam; Jordan, Nick; Gilgenbach, Ronald; Lau, Y. Y.

2014-10-01

Planar foil ablation experiments are being conducted on the Linear Transformer Driver (LTD) at the University of Michigan. The experiment consists of a 400 nm-thick, Al planar foil and a current return post. An optical fiber is placed perpendicular to the magnetic field and linear polarizers are used to isolate the pi and sigma lines. The LTD is charged to +/-70 kV with approximately 400-500 kA passing through the foil. Laser shadowgraphy has previously imaged the plasma and measured anisotropy in the Magneto Rayleigh-Taylor (MRT) instability. Localized magnetic field measurements using Zeeman splitting during the current rise is expected to yield some insight into this anisotropy. Initial experiments use Na D lines of Al foils seeded with sodium to measure Zeeman splitting. Several ion lines are also currently being studied, such as Al III and C IV, to probe the higher temperature core plasma. In planned experiments, several lens-coupled optical fibers will be placed across the foil, and local magnetic field measurements will be taken to measure current division within the plasma. This work was supported by US DoE. S.G. Patel and A.M. Steiner supported by NPSC funded by Sandia. D.A. Yager supported by NSF fellowship Grant DGE 1256260.

Cellulose Insulation

Science.gov (United States)

1980-01-01

Fire retardant cellulose insulation is produced by shredding old newspapers and treating them with a combination of chemicals. Insulating material is blown into walls and attics to form a fiber layer which blocks the flow of air. All-Weather Insulation's founders asked NASA/UK-TAP to help. They wanted to know what chemicals added to newspaper would produce an insulating material capable of meeting federal specifications. TAP researched the query and furnished extensive information. The information contributed to successful development of the product and helped launch a small business enterprise which is now growing rapidly.

Temperature dependence of the beam-foil interaction

International Nuclear Information System (INIS)

Gay, T.J.; Berry, H.G.

1978-01-01

The beam energy dependence between 50 and 200 keV of the linear polarization fraction (M/I) of the 2s 1 S--3p 1 P, 5016 A transition in He I on temperature was measured. The thin carbon exciter foils were heated externally by nichrome resistance elements. The measurements of Hight et al. are duplicated; the energy and current dependences are the same for corresponding between beam heating and external heating. It was also observed that γ, the number of slow secondary electrons produced per incident ion, decreases with increasing foil temperature. These two effects, in conjunction, offer a plausible explanation for the variation of polarization with beam current density. 5 figures

Continuum radiation emitted from transition metals under ion bombardment

International Nuclear Information System (INIS)

El Boujlaidi, A.; Kaddouri, A.; Ait El Fqih, M.; Hammoum, K.; Aouchiche, H.

2012-01-01

Optical emission of transition metals has been studied during 5 keV Kr + ions bombardment within and without oxygen atmosphere in the colliding chamber. The observed spectra consist of a series of discrete lines superimposed on a broad continuum. Generally, the emission intensity was influenced by the presence of oxygen giving rise to transient effects as well as to an increase in the line intensity. The behaviours of spectral lines were successfully explained in term of electron-transfer process between the excited sputtered atom and the solid surface. In this work, we have focused our study on the continuous radiation emitted during ion bombardment. The experimental results suggest that the continuum emission depends on the nature of metal and very probably related to its electronic structure. The collective deactivation of 3d-shell electrons appears to play a role in the emission of this radiation. The observed enhancement in the presence of oxygen is probably due to a significant contribution of the oxide molecules. (authors)

Dual scattering foil design for poly-energetic electron beams

International Nuclear Information System (INIS)

Kainz, K K; Antolak, J A; Almond, P R; Bloch, C D; Hogstrom, K R

2005-01-01

The laser wakefield acceleration (LWFA) mechanism can accelerate electrons to energies within the 6-20 MeV range desired for therapy application. However, the energy spectrum of LWFA-generated electrons is broad, on the order of tens of MeV. Using existing laser technology, the therapeutic beam might require a significant energy spread to achieve clinically acceptable dose rates. The purpose of this work was to test the assumption that a scattering foil system designed for a mono-energetic beam would be suitable for a poly-energetic beam with a significant energy spread. Dual scattering foil systems were designed for mono-energetic beams using an existing analytical formalism based on Gaussian multiple-Coulomb scattering theory. The design criterion was to create a flat beam that would be suitable for fields up to 25 x 25 cm 2 at 100 cm from the primary scattering foil. Radial planar fluence profiles for poly-energetic beams with energy spreads ranging from 0.5 MeV to 6.5 MeV were calculated using two methods: (a) analytically by summing beam profiles for a range of mono-energetic beams through the scattering foil system, and (b) by Monte Carlo using the EGS/BEAM code. The analytic calculations facilitated fine adjustments to the foil design, and the Monte Carlo calculations enabled us to verify the results of the analytic calculation and to determine the phase-space characteristics of the broadened beam. Results showed that the flatness of the scattered beam is fairly insensitive to the width of the input energy spectrum. Also, results showed that dose calculated by the analytical and Monte Carlo methods agreed very well in the central portion of the beam. Outside the useable field area, the differences between the analytical and Monte Carlo results were small but significant, possibly due to the small angle approximation. However, these did not affect the conclusion that a scattering foil system designed for a mono-energetic beam will be suitable for a poly

The effect of oxygen ion beam bombardment on the properties of tin indium oxide/polyethylene terephthalate complex

International Nuclear Information System (INIS)

Li, Li; Liu, Honglin; Zou, Lin; Ding, Wanyu; Ju, Dongying; Chai, Weiping

2013-01-01

The tin indium oxide (ITO) films were deposited onto the polyethylene terephthalate (PET) surface that has been bombarded by an O ion beam. The variation of the O bombardment time resulted in the production of ITO/PET complex with different properties. Characterization by four-point probe measurement after the bending fatigue test showed that the adhesion property of the ITO/PET complex could be improved by the increase of O bombardment time while little change of electrical resistivity was observed. Scanning electron microscopy results showed that after the bending fatigue test, the nano scale seams and micro scale trenches appeared at the surface of the ITO/PET complex. The former was only the cracks of ITO film, which has little influence on the continuity and electrical resistivity of ITO film. On the contrary, the micro scale trenches were caused by the peeling off of ITO chips at the cracks, which mainly influenced the continuity and electrical resistivity of ITO film. With the increase of O bombardment time, the number and length of the micro scale trenches decreased. X-ray photoelectron spectrometry characterization showed that with the increase of O bombardment time, parts of the methylene C bonds were transformed into C=O bonds, which could be broken to form C-O-In(Sn) bonds at the initial stage of ITO film growth. By these C-O-In(Sn) crosslink bonds, the ITO film could adhere well onto the PET and the ITO/PET complex display better anti-bending fatigue property. Finally, in the context of the application of the ITO/PET complex as a flexible electrode substrate, the present work reveals a simple way to crosslink them, as well as the physicochemical mechanism happening at the interface of complex. - Highlights: • Polyethylene terephthalate (PET) surface was bombarded by N ions. • Tin indium oxide (ITO) film was deposited on bombarded PET surface. • By bombardment, methylene C bond on PET surface was broken and replaced by C=O bond. • C=O bond was

The effect of oxygen ion beam bombardment on the properties of tin indium oxide/polyethylene terephthalate complex

Energy Technology Data Exchange (ETDEWEB)

Li, Li; Liu, Honglin; Zou, Lin [School of Materials Science and Engineering, Dalian Jiaotong University, Dalian 116028 (China); Ding, Wanyu, E-mail: dwysd_2000@163.com [School of Materials Science and Engineering, Dalian Jiaotong University, Dalian 116028 (China); Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116028 (China); Ju, Dongying [Department of Material Science and Engineering, Saitama Institute of Technology, Fukaya 369-0293 (Japan); Chai, Weiping [School of Materials Science and Engineering, Dalian Jiaotong University, Dalian 116028 (China)

2013-10-31

The tin indium oxide (ITO) films were deposited onto the polyethylene terephthalate (PET) surface that has been bombarded by an O ion beam. The variation of the O bombardment time resulted in the production of ITO/PET complex with different properties. Characterization by four-point probe measurement after the bending fatigue test showed that the adhesion property of the ITO/PET complex could be improved by the increase of O bombardment time while little change of electrical resistivity was observed. Scanning electron microscopy results showed that after the bending fatigue test, the nano scale seams and micro scale trenches appeared at the surface of the ITO/PET complex. The former was only the cracks of ITO film, which has little influence on the continuity and electrical resistivity of ITO film. On the contrary, the micro scale trenches were caused by the peeling off of ITO chips at the cracks, which mainly influenced the continuity and electrical resistivity of ITO film. With the increase of O bombardment time, the number and length of the micro scale trenches decreased. X-ray photoelectron spectrometry characterization showed that with the increase of O bombardment time, parts of the methylene C bonds were transformed into C=O bonds, which could be broken to form C-O-In(Sn) bonds at the initial stage of ITO film growth. By these C-O-In(Sn) crosslink bonds, the ITO film could adhere well onto the PET and the ITO/PET complex display better anti-bending fatigue property. Finally, in the context of the application of the ITO/PET complex as a flexible electrode substrate, the present work reveals a simple way to crosslink them, as well as the physicochemical mechanism happening at the interface of complex. - Highlights: • Polyethylene terephthalate (PET) surface was bombarded by N ions. • Tin indium oxide (ITO) film was deposited on bombarded PET surface. • By bombardment, methylene C bond on PET surface was broken and replaced by C=O bond. • C=O bond was

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

International Nuclear Information System (INIS)

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

1998-01-01

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

Foil Bearing Coating Behavior in CO₂

Energy Technology Data Exchange (ETDEWEB)

Walker, Matthew [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Kruizenga, Alan Michael [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Pasch, James Jay [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Fleming, Darryn [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-08-01

The Sandia S-CO₂ Recompression Closed Brayton Cycle (RCBC) utilizes a series of gas foil bearings in its turbine-alternator-compressors. At high shaft rotational speed these bearings allow the shaft to ride on a cushion of air. Conversely, during startup and shutdown, the shaft rides along the foil bearing surface. Low-friction coatings are used on bearing surfaces in order to facilitate rotation during these periods. An experimental program was initiated to elucidate the behavior of coated bearing foils in the harsh environments of this system. A test configuration was developed enabling long duration exposure tests, followed by a range of analyses relevant to their performance in a bearing. This report provides a detailed overview of this work. The results contained herein provide valuable information in selecting appropriate coatings for more advanced future bearing-rig tests at the newly established test facility in Sandia-NM.

Long-Term Memory for Pictures under Conditions of Difficult Foil Discriminability.

Science.gov (United States)

Homa, Donald; Viera, Cynthia

Research has demonstrated that subjects are sensitive to both thematic and non-thematic information in pictorial stimuli. Three experiments were conducted to investigate memory for pictures under conditions of difficult foil discriminability and lengthy retention intervals. The foils differed from the studied persons in the number and quality of…

Ion bombardment effect on surface state of metal

International Nuclear Information System (INIS)

Vaulin, E.P.; Georgieva, N.E.; Martynenko, T.P.

1990-01-01

The effect of slow argon ion bombardment on the surface microstructure of polycrystalline copper as well as the effect of surface state on sputtering of D-16 polycrystalline alloy are experimentally studied. Reduction of copper surface roughness is observed. It is shown that the D-16 alloy sputtering coefficient is sensitive to the surface state within the limits of the destructed surface layer

Mechanical design and vibro-acoustic testing of ultrathin carbon foils for a spacecraft instrument

Energy Technology Data Exchange (ETDEWEB)

Bernardin, John D [Los Alamos National Laboratory; Baca, Allen G [SNL

2009-01-01

IBEX-Hi is an electrostatic analyzer spacecraft instrument designed to measure the energy and flux distribution of energetic neutral atoms (ENAs) emanating from the interaction zone between the Earth's solar system and the Milky Way galaxy. A key element to this electro-optic instrument is an array of fourteen carbon foils that are used to ionize the ENAs. The foils are comprised of an ultrathin (50-100 {angstrom} thick) layer of carbon suspended across the surface of an electroformed Nickel wire screen, which in turn is held taught by a metal frame holder. The electro formed orthogonal screen has square wire elements, 12.7 {micro}m thick, with a pitch of 131.1 wires/cm. Each foil holder has an open aperture approximately 5 cm by 2.5 cm. Designing and implementing foil holders with such a large surface area has not been attempted for spaceflight in the past and has proven to be extremely challenging. The delicate carbon foils are subject to fatigue failure from the large acoustic and vibration loads that they will be exposed to during launch of the spacecraft. This paper describes the evolution of the foil holder design from previous space instrument applications to a flight-like IBEX-Hi prototype. Vibro-acoustic qualification tests of the IBEX-Hi prototype instrument and the resulting failure of several foils are summarized. This is followed by a discussion of iterative foil holder design modifications and laser vibrometer modal testing to support future fatigue failure analyses, along with additional acoustic testing of the IBEX-Hi prototype instrument. The results of these design and testing activities are merged and the resulting flight-like foil holder assembly is proposed.

A molecular dynamics study of helium bombardments on tungsten nanoparticles

Science.gov (United States)

Li, Min; Hou, Qing; Cui, Jiechao; Wang, Jun

2018-06-01

Molecular dynamics simulations were conducted to study the bombardment process of a single helium atom on a tungsten nanoparticle. Helium atoms ranging from 50 eV to 50 keV were injected into tungsten nanoparticles with a diameter in the range of 2-12 nm. The retention and reflection of projectiles and sputtering of nanoparticles were calculated at various times. The results were found to be relative to the nanoparticle size and projectile energy. The projectile energy of 100 eV contributes to the largest retention of helium atoms in tungsten nanoparticles. The most obvious difference in reflection exists in the range of 3-10 keV. Around 66% of sputtering atoms is in forward direction for projectiles with incident energy higher than 10 keV. Moreover, the axial direction of the nanoparticles was demonstrated to influence the bombardment to some degree.

Statistical characterization of surface defects created by Ar ion bombardment of crystalline silicon

International Nuclear Information System (INIS)

Ghazisaeidi, M.; Freund, J. B.; Johnson, H. T.

2008-01-01

Ion bombardment of crystalline silicon targets induces pattern formation by the creation of mobile surface species that participate in forming nanometer-scale structures. The formation of these mobile species on a Si(001) surface, caused by sub-keV argon ion bombardment, is investigated through molecular dynamics simulation of Stillinger-Weber [Phys. Rev. B 31, 5262 (1985)] silicon. Specific criteria for identifying and classifying these mobile atoms based on their energy and coordination number are developed. The mobile species are categorized based on these criteria and their average concentrations are calculated

Alpha Oscillations during Incidental Encoding Predict Subsequent Memory for New "Foil" Information.

Science.gov (United States)

Vogelsang, David A; Gruber, Matthias; Bergström, Zara M; Ranganath, Charan; Simons, Jon S

2018-05-01

People can employ adaptive strategies to increase the likelihood that previously encoded information will be successfully retrieved. One such strategy is to constrain retrieval toward relevant information by reimplementing the neurocognitive processes that were engaged during encoding. Using EEG, we examined the temporal dynamics with which constraining retrieval toward semantic versus nonsemantic information affects the processing of new "foil" information encountered during a memory test. Time-frequency analysis of EEG data acquired during an initial study phase revealed that semantic compared with nonsemantic processing was associated with alpha decreases in a left frontal electrode cluster from around 600 msec after stimulus onset. Successful encoding of semantic versus nonsemantic foils during a subsequent memory test was related to decreases in alpha oscillatory activity in the same left frontal electrode cluster, which emerged relatively late in the trial at around 1000-1600 msec after stimulus onset. Across participants, left frontal alpha power elicited by semantic processing during the study phase correlated significantly with left frontal alpha power associated with semantic foil encoding during the memory test. Furthermore, larger left frontal alpha power decreases elicited by semantic foil encoding during the memory test predicted better subsequent semantic foil recognition in an additional surprise foil memory test, although this effect did not reach significance. These findings indicate that constraining retrieval toward semantic information involves reimplementing semantic encoding operations that are mediated by alpha oscillations and that such reimplementation occurs at a late stage of memory retrieval, perhaps reflecting additional monitoring processes.

Structural stiffness and Coulomb damping in compliant foil journal bearings: Theoretical considerations

Science.gov (United States)

Ku, C.-P. Roger; Heshmat, Hooshang

1994-07-01

Compliant foil bearings operate on either gas or liquid, which makes them very attractive for use in extreme environments such as in high-temperature aircraft turbine engines and cryogenic turbopumps. However, a lack of analytical models to predict the dynamic characteristics of foil bearings forces the bearing designer to rely on prototype testing, which is time-consuming and expensive. In this paper, the authors present a theoretical model to predict the structural stiffness and damping coefficients of the bump foil strip in a journal bearing or damper. Stiffness is calculated based on the perturbation of the journal center with respect to its static equilibrium position. The equivalent viscous damping coefficients are determined based on the area of a closed hysteresis loop of the journal center motion. The authors found, theoretically, that the energy dissipated from this loop was mostly contributed by the frictional motion between contact surfaces. In addition, the source and mechanism of the nonlinear behavior of the bump foil strips were examined. With the introduction of this enhanced model, the analytical tools are now available for the design of compliant foil bearings.

Investigation of /sup 16/O+/sup 27/Al reaction at bombarding energies below 5. 3 MeV/A

Energy Technology Data Exchange (ETDEWEB)

Wen-Qing, Shen; Yong-Tai, Zhu; Wen-Long, Zhan; Zhong-Yan, Guo; Shu-Zhi, Yin; Wei-Min, Qiao; En-Chiu, Wu

1987-03-01

Quasi elastic and deep inelastic collision induced by /sup 16/O+/sup 27/Al at the bombarding energies below 5.3 MeV/A have been studied in detail. Experimental angular energy atomic charge distribution and contour plots of the differential cross sections d/sup 3/sigma/dEd..cap omega..dZ on E-theta plan are presented, their evolution with the bombarding energies are analysed. The competion between quasi elastic and deep inelastic collision as a functon of the bombarding energies has been discussed.

Prediction and characterization of heat-affected zone formation due to neighboring nickel-aluminum multilayer foil reaction

Energy Technology Data Exchange (ETDEWEB)

Adams, David P. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Hirschfeld, Deidre A. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Hooper, Ryan J. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Manuel, Michelle V. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

2015-09-01

Reactive multilayer foils have the potential to be used as local high intensity heat sources for a variety of applications. Much of the past research effort concerning these materials have focused on understanding the structure-property relationships of the foils that govern the energy released during a reaction. To enhance the ability of researchers to more rapidly develop technologies based on reactive multilayer foils, a deeper and more predictive understanding of the relationship between the heat released from the foil and microstructural evolution in the neighboring materials is needed. This work describes the development of a numerical model for the purpose of evaluating new foil-substrate combinations for screening and optimization. The model is experimentally validated using a commercially available Ni-Al multilayer foils and different alloys.

Charge fraction of 6.0 MeV/n heavy ions with a carbon foil: Dependence on the foil thickness and projectile atomic number

CERN Document Server

Sato, Y; Muramatsu, M; Murakami, T; Yamada, S; Kobayashi, C; Kageyama, Y; Miyoshi, T; Ogawa, H; Nakabushi, H; Fujimoto, T; Miyata, T; Sano, Y

2003-01-01

We measured the charge fraction of 6.0 MeV/n heavy ions (C, Ne, Si, Ar, Fe and Cu) with a carbon foil at the NIRS-HIMAC injector. At this energy they are stripped with a carbon foil before being injected into two synchrotron rings with a maximum energy of 800 MeV/n. In order to find the foil thickness (D sub E) at which an equilibrium charge state distribution occurs, and to study the dependence of the D sub E -values on the projectile atomic number, we measured the exit charge fractions for foil thicknesses of between 10 and 350 mu g/cm sup 2. The results showed that the D sub E -values are 21.5, 62.0, 162, 346, 121, 143 mu g/cm sup 2 for C, Ne, Si, Ar, Fe, Cu, respectively. The fraction of Ar sup 1 sup 8 sup + ions was actually improved to 33% at 320 mu g/cm sup 2 from approx 15% at 100 mu g/cm sup 2. For Fe and Cu ions, the D sub E -values were found to be only 121 and 143 mu g/cm sup 2; there is a large gap between Ar and Fe, which is related to the differences in the ratio of the binding energy of the K-...

Experimental thin-target and thick-target yields for natOs(α, xn)Pt, natOs(α, X)Os, Ir and natMo(p, xn)Tc nuclear reactions from threshold up to 38 and 45 MeV, by combined single and stacked foil techniques

International Nuclear Information System (INIS)

Birattari, Claudio; Bonardi, Mauro; Gini, Luigi; Groppi, Flavia; Menapace, Enzo

2002-01-01

The experimental values of thin-target excitation functions for the nuclear reactions: nat Os(α, X) 188,189,191 Pt, 192g,194m Ir in the energy range 11 - 38 MeV and nat Mo(p, xn) 94g,95g,95m,96(m+g) Tc in the energy range 5 - 44 MeV are presented. The experimental values were obtained by cyclotron activation followed by off-line HPGe γ-spectrometry and corrected at the End Of an Instantaneous Bombardment, EOIB. In different cases use was made of single foil and stacked foil techniques, which present significantly different advantages and disadvantages. The thin-target yield values can be easily either numerically or analytically integrated, as a function of both incoming particle energy and energy loss in target itself, in order to calculate apriori the thick-target yield of various radionuclides under any different experimental condition. Moreover, the thin-target yields are directly related to the effective cross-sections of various nuclear reaction channels involved. The data are of relevant interest for optimizing cyclotron production of platinum and technetium radionuclides to be used as radiotracers for metallo-biochemical, biomedical, toxicological and environmental studies. (author)

Novel technique of making thin target foil of high density material via rolling method

Science.gov (United States)

Gupta, C. K.; Rohilla, Aman; Singh, R. P.; Singh, Gurjot; Chamoli, S. K.

2018-05-01

The conventional rolling method fails to yield good quality thin foils of thicknesses less than 2 mg/cm2 for high density materials with Z ≥ 70 (e.g. gold, lead). A special and improved technique has been developed to obtain such low thickness good quality gold foils by rolling method. Using this technique thin gold foils of thickness in the range of 0.850-2.5 mg/cm2 were obtained in the present work. By making use of alcohol during rolling, foils of thickness 1 mg/cm2 can be obtained in shorter time with less effort.

Stable transformation of the oomycete, Phytophthora infestans, using microprojectile bombardment

DEFF Research Database (Denmark)

Cvitanich, Cristina; Judelson, Howard S.

2003-01-01

Germinated asexual sporangia, zoospores, and mycelia of Phytophthora infestans were transformed to G418-resistance by microprojectile bombardment. After optimization, an average of 14 transformants/shot were obtained, using 10(6) germinated sporangia and gold particles coated with 1 microg...

Damage and redistribution of impurities by ionic bombardment

International Nuclear Information System (INIS)

Tognetti, N.P.

1982-01-01

Some aspects of displacement collisions in solids bombarded with ions in the medium energy range have been studied using the backscattering and channelling techniques. The production of lattice damage and the spatial redistribution of atoms within the collision cascade were the two main effects considered and experimentally studied. A comprehensive study of disorder production in GaAs was carried out at 40 K for a variety of ions and ion energies, providing insight into the mechanisms of damage generation from both the macro and microscopic points of view. Experiments on thermal recovery of partially disordered substrates revealed that annealing occurs from approximately 100 K to 300 K. A direct procedure developed for the obtainment of damage profiles from backscattering-channelling measurements is described. The net spatial redistribution of displaced atoms, in combined impurity-matrix substrates was studied and compared with existing theories of ion beam mixing. The Ag-Si system was studied for a wide range of fluence of bombarding Ar + ions. Furthermore, the contribution of atomic mixing in the experimental observation of Ge implantation at high doses into Si is discussed. (M.E.L) [es

Flaking and blistering on He and Ne bombardments

International Nuclear Information System (INIS)

Kamada, K.; Naramoto, H.

1979-01-01

Large scale exfoliation formed by 300 keV He + bombardment of niobium without any preceding blistering is investigated, in comparison with the blistering due to 450 and 850 keV Ne + bombardments. In-situ observations of the erosion processes were performed in a scanning electron microscope connected to the Van de Graaff. Critical doses of 7.2 x 10 17 He + /cm 2 , 2.4 x 10 17 Ne + /cm 2 and 4.0 x 10 17 Ne + /cm 2 were obtained for the 300 keV He flaking, 450 keV Ne blistering and 850 keV Ne blistering, respectively. The He flaking was presumed to be due to brittle fashion peeling-off of the surface layer by the bending moment driven by the internal gas pressure. The blistering, on the other hand, was presumed to be the result of the ductile fashion spreading of the lenticular bubble in the sub-surface layer. The necessary pressure for the peeling-off of the cover was calculated, and was speculated to be able to work as the driving force for the flaking from its unexpectedly low values. Fractographies under the exfoliations were discussed for both flaking and blistering. (author)

Design of organic complementary circuits and systems on foil

CERN Document Server

Abdinia, Sahel; Cantatore, Eugenio

2015-01-01

This book describes new approaches to fabricate complementary organic electronics, and focuses on the design of circuits and practical systems created using these manufacturing approaches. The authors describe two state-of-the-art, complementary organic technologies, characteristics and modeling of their transistors and their capability to implement circuits and systems on foil. Readers will benefit from the valuable overview of the challenges and opportunities that these extremely innovative technologies provide. ·         Demonstrates first circuits implemented using specific complementary organic technologies, including first printed analog to digital converter, first dynamic logic on foil and largest complementary organic circuit ·         Includes step-by-step design from single transistor level to complete systems on foil ·         Provides a platform for comparing state-of-the-art complementary organic technologies and for comparing these with other similar technologies, spec...

Nondestructive analysis of silver in gold foil using synchrotron radiation X-ray fluorescence spectrometry

International Nuclear Information System (INIS)

Kasamatsu, Masaaki; Suzuki, Yasuhiro; Suzuki, Shinichi; Nakanishi, Toshio; Shimoda, Osamu; Nishiwaki, Yoshinori; Miyamoto, Naoki

2005-01-01

Small particles of gold foil detached from an indoor decoration might be important evidence to associate a suspect with a crime scene. We have investigated the application of elemental analysis using synchrotron radiation X-ray fluorescence spectrometry to discriminate small particles of gold foil. Eight kinds of gold foil samples collected in Japan were used in the experiments. As a result of synchrotron radiation X-ray fluorescence spectrometry, only two elements, gold and silver, were detected from all gold foil samples. The intensity ratios of AgK α /AuL α showed good correlation with the content ratios of Ag/Au. The variation of intensity ratio within a same sample was sufficiently small compared with those of different samples. Therefore the comparison of this intensity ratio can be an effective method to discriminate small particles originating from different types of gold foil. (author)

Fabrication of free-standing copper foils covered with highly-ordered copper nanowire arrays

Science.gov (United States)

Zaraska, Leszek; Sulka, Grzegorz D.; Jaskuła, Marian

2012-07-01

The through-hole nanoporous anodic aluminum oxide (AAO) membranes with relatively large surface area (ca. 2 cm2) were employed for fabrication of free-standing and mechanically stable copper foils covered with close-packed and highly-ordered copper nanowire arrays. The home-made AAO membranes with different pore diameters and interpore distances were fabricated via a two-step self-organized anodization of aluminum performed in sulfuric acid, oxalic acid and phosphoric acid followed by the pore opening/widening procedure. The direct current (DC) electrodeposition of copper was performed efficiently on both sides of AAO templates. The bottom side of the AAO templates was not insulated and consequently Cu nanowire arrays on thick Cu layers were obtained. The proposed template-assisted fabrication of free-standing copper nanowire array electrodes is a promising method for synthesis of nanostructured current collectors. The composition of Cu nanowires was confirmed by energy dispersive X-Ray spectroscopy (EDS) and X-ray diffraction (XRD) analyses. The structural features of nanowires were evaluated from field emission scanning electron microscopy (FE-SEM) images and compared with the characteristic parameters of anodic alumina membranes.

Fabrication of free-standing copper foils covered with highly-ordered copper nanowire arrays

International Nuclear Information System (INIS)

Zaraska, Leszek; Sulka, Grzegorz D.; Jaskuła, Marian

2012-01-01

The through-hole nanoporous anodic aluminum oxide (AAO) membranes with relatively large surface area (ca. 2 cm 2 ) were employed for fabrication of free-standing and mechanically stable copper foils covered with close-packed and highly-ordered copper nanowire arrays. The home-made AAO membranes with different pore diameters and interpore distances were fabricated via a two-step self-organized anodization of aluminum performed in sulfuric acid, oxalic acid and phosphoric acid followed by the pore opening/widening procedure. The direct current (DC) electrodeposition of copper was performed efficiently on both sides of AAO templates. The bottom side of the AAO templates was not insulated and consequently Cu nanowire arrays on thick Cu layers were obtained. The proposed template-assisted fabrication of free-standing copper nanowire array electrodes is a promising method for synthesis of nanostructured current collectors. The composition of Cu nanowires was confirmed by energy dispersive X-Ray spectroscopy (EDS) and X-ray diffraction (XRD) analyses. The structural features of nanowires were evaluated from field emission scanning electron microscopy (FE-SEM) images and compared with the characteristic parameters of anodic alumina membranes.

Thermal insulation

International Nuclear Information System (INIS)

Aspden, G.J.; Howard, R.S.

1988-01-01

The patent concerns high temperature thermal insulation of large vessels, such as the primary vessel of a liquid metal cooled nuclear reactor. The thermal insulation consists of multilayered thermal insulation modules, and each module comprises a number of metal sheet layers sandwiched between a back and front plate. The layers are linked together by straps and clips to control the thickness of the module. (U.K.)

Flapping foil power generator performance enhanced with a spring-connected tail

Science.gov (United States)

Liu, Zhengliang; Tian, Fang-Bao; Young, John; Lai, Joseph C. S.

2017-12-01

The flexibility effects on the performance of a flapping foil power generator are numerically studied by using the immersed boundary-lattice Boltzmann method at a Reynolds number of 1100. The flapping foil system consists of a rigid NACA0015 foil undergoing harmonic pitch and plunge motions and a passively actuated flat plate pinned to the trailing edge of the rigid foil. The flexibility is modeled by a torsional spring model at the conjuncture of the rigid foil and the tail. Here, a parametric study on mass density and natural frequency is conducted under the optimum kinematic condition of the rigid system identified from the literature and numerical simulations made for reduced frequency f* = 0.04-0.24 and pitch amplitude θ0 = 40°-90°. Four typical cases are discussed in detail by considering time histories of hydrodynamic loads and tail deformations under the optimal and non-optimal kinematic conditions. Results show that under the rigid-system optimal kinematic condition, a tail with appropriate mass density (μ = 0.60) and resonant frequency ( fr*=1.18 ) can improve the maximum efficiency by 7.24% accompanied by an increase of 6.63% in power compared to those of a rigid foil with a rigid tail. This is because the deflection of the tail reduces the low pressure region on the pressure surface (i.e., the lower surface during the upstroke or the upper surface during the downstroke) caused by the leading edge vortex after the stroke reversal, resulting in a higher efficiency. At high flapping frequencies, a spring-connected tail ( fr*=0.13 ) eliminates the large spike in the moment observed in high stiffness cases, reducing the power required for the pitch motion, resulting in 117% improvement in efficiency over that with a rigid tail at a reduced frequency of 0.24.

On the reasons for bombarding uranium with slow neutrons

International Nuclear Information System (INIS)

Xu Diyu

1997-01-01

Form the concepts of slow neutrons, the binding energy and the excitation energy of complex nuclei, and the activation energy in nuclear fission, the four reasons for bombarding uranium with slow neutrons are summed up. Not only the reasons for uranium fission are brought in light, but also the micromechanism is dealt with

Flexible, durable proton energy degraders for the GE PETtrace

Energy Technology Data Exchange (ETDEWEB)

Engle, J. W.; Gagnon, K.; Severin, G. W.; Valdovinos, H. F.; Nickles, R. J.; Barnhart, T. E. [Chemistry Division - Isotopes, Inorganics and Actinides, Los Alamos National Laboratory, Los Alamos, NM (United States); Department of Radiation Oncology, University of Washington, Seattle, WA (United States); Hevesy Laboratory, Danish Technical University, Risoe (Denmark); Department of Medical Physics, University of Wisconsin, WI, Madison (United States)

2012-12-19

In order to limit the formation of radioisotopic impurities during proton bombardments of solid targets, two methods of introducing degrader foils into the beam upstream of the target were tested. The first design uses a 445 {mu}m thick fixed degrader machined from a single piece of aluminum. The second design permits introduction of foils made of any material and was tested with foils as thick as 635 {mu}m (also aluminium). In both cases, the foils are cooled with by water flowing through an annular channel outside the radius of the beam. Both designs proved durable and tolerated proton beam currents in excess of 80 {mu}A.

The transmission of fast molecular ions through thin foils

International Nuclear Information System (INIS)

Pietsch, W.J.; Gemmell, D.S.; Cooney, P.J.; Kanter, E.P.; Kurath, D.; Ratkowski, A.J.; Vager, Z.; Zabransky, B.J.

1980-01-01

We present new results on the transmission of fast molecular ions through thin foils and propose a mechanism for the transmission process. The main feature of the postulated mechanism is that a finite fraction of the incident molecular beam does not undergo a strong Coulomb explosion while traversing the foil. Because the emerging fragments are at large internuclear separations, there is an enhanced probability for the formation of bound, long-range, excited electronic states following electron capture at the rear surface of the target. (orig.)

Numerical Analysis of Thermal Stresses around Fasteners in Composite Metal Foils

Science.gov (United States)

Nammi, S. K.; Butt, J.; –L Mauricette, J.; Shirvani, H.

2017-12-01

The process of composite metal foil manufacturing (CMFM) has reduced a number of limitations associated with commercial additive manufacturing (AM) methods. The existing metal AM machines are restricted by their build envelope and there is a growing market for the manufacture of large parts using AM. These parts are subsequently manufactured in fragments and are fastened together. This paper analyses the thermal stresses around cylindrical fasteners for three layered metal composite parts consisting of aluminium foil, brazing paste and copper foil layers. The investigation aims to examine the mechanical integrity of the metallurgically bonded aluminium/copper foils of 100 micron thickness manufactured in a disc shape. A cylindrical fastener set at an elevated temperature of 100 °C is fitted in the middle of the disc which results in a steady-state thermal distribution. Radial and shear stresses are computed using finite element method which shows that non-zero shear stresses developed by the copper layer inhibit the axial slippage of the fastener and thereby establishing the suitability of rivet joints for CMFM parts.

Flapping propulsion with side-by-side pitching foils

Science.gov (United States)

Huera-Huarte, Francisco

2016-11-01

Fish schools are one of the most common types of collective behaviour observed in nature. One of the reasons why fish swim in groups, is to reduce the cost of transport of the school. In this work we explore the propulsive performance of two foils flapping in a symmetric configuration, i.e. with an out-of-phase flapping motion. Direct thrust measurements and Particle Image Velocimetry (PIV) allowed a detailed examination of the forces and the wake generated by the system, for different kinematics (swept angles and frequencies) and shaft separations. For certain specific cases, volumetric PIV shows major differences on how the different structures in the wake of the system evolve, depending on the imposed kinematics and the side-by-side separation between the foils. Results obtained will be compared against data produced with isolated flapping foils with similar imposed kinematics, with the aim to better understand the interactions between both and the performance of the system as a whole. The author would like to acknowledge the financial support provided by the Spanish Ministerio de Economia y competitividad (MINECO) through Grant DPI2015-71645-P.

Emission of positive oxygen ions from ion bombardment of adsorbate-covered metal surfaces

International Nuclear Information System (INIS)

Kaurin, M.G.

1989-01-01

During ion bombardment of metal surfaces, collision cascades can result in the emission of sputtered secondary ions. Recent experiments, however, have suggested that the emission of positive ions of electronegative adsorbates can result from electronic processes rather than from processes involving elastic collisions. This dissertation presents the results of experiments studying the emission of positive oxygen ions from oxygen- and carbon-monoxide-covered transition metal surfaces during bombardment by 25-250 keV ions of neon, argon, and krypton. The systems studied may be grouped into four categories. For a nickel substrate with adsorbed oxygen, the emission of positive oxygen ions proceeds through collision cascades. For titanium and niobium with adsorbed oxygen, the emission of positive oxygen ions is proportional to the primary ion velocity, consistent with emission from electronic processes; for a given primary ion velocity, the oxygen ion yield is independent of primary ion species. For substrates of molybdenum and tungsten, the oxygen yield is proportional to primary ion velocity, but the yield also depends on the primary ion species for a given primary ion velocity in a manner that is consistent with emission resulting from electronic processes. For these two groups, except for titanium, the yields during neon ion bombardment do not extrapolate (assuming linearity with primary ion velocity) to a nonzero value at zero beam velocity. The magnitude of the oxygen ion yields from these targets is not consistent with that expected if the emission were induced by secondary electrons emitted during the ion bombardment

Selecting lineup foils in eyewitness identification experiments: experimental control and real-world simulation.

Science.gov (United States)

Clark, S E; Tunnicliff, J L

2001-06-01

Experimental research on eyewitness identification follows a standard principle of experimental design. Perpetrator-present and perpetrator-absent lineups are constructed with the same foils, so that the two conditions are identical except for the presence or absence ofthe trueperpetrator ofthe crime. However, this aspect of the design simulates conditions that do not correspond to those of real criminal investigations. Specifically, these conditions can create perp-absent lineups in which the foils are selected based on their similarity to an unknown person--the real perpetrator. Analysis of the similarity relations predicts that when foils for perp-absent lineups are selected based on their match to the perpetrator the false identification rate will be lower than if the foils are selected based on their match to the innocent suspect. This prediction was confirmed in an experiment that compared these two perp-absent lineup conditions. These results suggest that false identification rates in previous experiments would have been higher if the foils had been selected based on their match to the innocent suspect, rather than the absent perpetrator.

Investigations on electroluminescent tapes and foils in relation to their applications in automotive

Science.gov (United States)

Plotog, Ioan

2015-02-01

The electroluminescent (EL) tapes or foils having barrier films for an additional level of protection against the toughest environments conditions, offer a large area of applications. The EL lights, due to their characteristics, began to be used not only in the entertainment industry, but also for automotive and aerospace applications. In the paper, the investigations regarding EL foils technical performances in relation to their applications as light sources in automotive ambient light were presented. The experiments were designed based on the results of EL foils electrical properties previous investigations done in laboratory conditions, taking into account the range of automotive ambient temperatures for sinusoidal alternative supply voltage. The measurements for different temperatures were done by keeping the EL foils into electronic controlled oven that ensures the dark enclosure offering conditions to use a lux-meter in order to measure and maintain under control light emission intensity. The experiments results define the EL foils characteristics as load in automotive ambient temperatures condition, assuring so the data for optimal design of a dedicated inverter.

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

International Nuclear Information System (INIS)

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

2013-01-01

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

Ion bombardment simulation: a review related to fusion radiation damage

International Nuclear Information System (INIS)

Brimhall, J.L.

1975-01-01

Prime emphasis is given to reviewing the ion bombardment data on the refractory metals molybdenum, niobium and vanadium which have been proposed for use in advanced fusion devices. The temperature and dose dependence of the void parameters are correlated among these metals. The effect of helium and hydrogen gas on the void parameters is also included. The similarities and differences of the response of these materials to high dose, high temperature radiation damage are evaluated. Comparisons are made with results obtained from stainless steel and nickel base alloys. The ion bombardment data is then compared and correlated, as far as possible, with existing neutron data on the refractory metals. The theoretically calculated damage state produced by neutrons and ions is also briefly discussed and compared to experimental data wherever possible. The advantages and limitations of ion simulation in relation to fusion radiation damage are finally summarized

Room temperature thin foil SLIM-cut using an epoxy paste: experimental versus theoretical results

International Nuclear Information System (INIS)

Bellanger, Pierre; Serra, Joao; Bouchard, Pierre-Olivier; Bernacki, Marc

2015-01-01

The stress induced lift-off method (SLIM) -cut technique allows the detachment of thin silicon foils using a stress inducing layer. In this work, results of SLIM-cut foils obtained using an epoxy stress inducing layer at room temperature are presented. Numerical analyses were performed in order to study and ascertain the important experimental parameters. The experimental and simulation results are in good agreement. Indeed, large area (5 × 5 cm 2 ) foils were successfully detached at room temperature using an epoxy thickness of 900 μm and a curing temperature of 150 °C. Moreover, three foils (5 × 3 cm 2 ) with thickness 135, 121 and 110 μm were detached from the same monocrystalline substrate. Effective minority carrier lifetimes of 46, 25 and 20 μs were measured using quasi-steady-state photoconductance technique in these foils after iodine ethanol surface passivation. (paper)

The development of fast tantalum foil targets for short-lived isotopes

CERN Document Server

Bennett, J R J; Drumm, P V; Ravn, H L

2003-01-01

The development of fast tantalum foil targets for short-lived isotopes was discussed. It was found that the effusion was faster but the diffusion out of the foils was a limiting factor. The performance of the targets at ISOLDE with beams of **1**1Li, **1**2Be and **1**4Be was also analyzed. (Edited abstract) 13 Refs.

GLASS AND SILICON FOILS FOR X-RAY SPACE TELESCOPE MIRRORS

Directory of Open Access Journals (Sweden)

M. MIKA

2011-12-01

Full Text Available Unique observations delivered by space X-ray imaging telescopes have been significantly contributing to important discoveries of current astrophysics. The telescopes’ most crucial part is a high throughput, heavily nested mirror array reflecting X-rays and focusing them to a detector. Future astronomical projects on large X-ray telescopes require novel materials and technologies for the construction of the reflecting mirrors. The future mirrors must be lightweight and precisely shaped to achieve large collecting area with high angular resolution of a few arc sec. The new materials and technologies must be cost-effective as well. Currently, the most promising materials are glass or silicon foils which are commercially produced on a large scale. A thermal forming process was used for the precise shaping of these foils. The forced and free slumping of the foils was studied in the temperature range of hot plastic deformation and the shapes obtained by the different slumping processes were compared. The shapes and the surface quality of the foils were measured by a Taylor Hobson contact profilemeter, a ZYGO interferometer and Atomic Forced Microscopy. In the experiments, both heat-treatment temperature and time were varied following our experiment design. The obtained data and relations can be used for modelling and optimizing the thermal forming procedure.

Surface damage studies of ETFE polymer bombarded with low energy Si ions (≤100 keV)

International Nuclear Information System (INIS)

Minamisawa, Renato Amaral; Almeida, Adelaide De; Budak, Satilmis; Abidzina, Volha; Ila, Daryush

2007-01-01

Surface studies of ethylenetetrafluoroethylene (ETFE), bombarded with Si in a high-energy tandem Pelletron accelerator, have recently been reported. Si ion bombardment with a few MeV to a few hundred keV energies was shown to be sufficient to produce damage on ETFE film. We report here the use of a low energy implanter with Si ion energies lower than 100 keV, to induce changes on ETFE films. In order to determine the radiation damage, ETFE bombarded films were simulated with SRIM software and analyzed with optical absorption photometry (OAP), Raman and Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy to show quantitatively the physical and chemical property changes. Carbonization occurs following higher dose implantation, and hydroperoxides were formed following dehydroflorination of the polymer

Effect of thickness of foil strippers in transmission of beams through 15 UD pelletron accelerator at IUAC

International Nuclear Information System (INIS)

Ojha, S.; Pankaj Kumar; Gargari, S.; Joshi, R.; Abhilash; Kabiraj, D.; Chopra, S.

2009-01-01

15 UD Pelletron accelerator at IUAC, New Delhi is equipped with a foil stripper and a gas stripper at high voltage terminal. Besides these, we have foil stripper assemblies at High Energy Dead Section (HEDS) of Pelletron and after analyser magnet. Incoming negative ion looses electrons when they pass through the strippers at terminal and becomes positively charged. The next foil stripper at HEDS increases the positive charge state of ion by removing more electrons which helps in delivering beams at higher energy. Typical thickness of carbon foils loaded in the foil stripper assembly in the terminal is around 4 microgram per square centimetre (4 μg/cm 2 ). Thicker foils were installed in the terminal assembly to study the effect of thickness of foil on charge state distribution and transmission of ion beams. Charge state distribution of ions produced out of molecular beam was also studied. In this paper we present and discuss the results and observations with thicker foils on ion as well as molecular beams. (author)

Applications of beam-foil spectroscopy to atomic collisions in solids

Science.gov (United States)

Sellin, I. A.

1976-01-01

Some selected papers presented at the Fourth International Conference on Beam-Foil Spectroscopy, whose results are of particular pertinence to ionic collision phenomena in solids, are reviewed. The topics discussed include solid target effects and means of surmounting them in the measurement of excited projectile ion lifetimes for low-energy heavy element ions; the electron emission accompanying the passage of heavy particles through solid targets; the collision broadening of X rays emitted from 100 keV ions moving in solids; residual K-shell excitation in chlorine ions penetrating carbon; comparison between 40 MeV Si on gaseous SiH4 targets at 300 mtorr and 40 MeV Si on Al; and the emergent surface interaction in beam-foil spectroscopy. A distinct overlap of interests between the sciences of beam-foil spectroscopy and atomic collisions in solids is pointed out.

Stripping Foil Issues for H- Injection into the CERN PSB at 160 MeV

CERN Document Server

Goddard, B; Bracco, C; Carli, C; Meddahi, M; Weterings, W J M

2010-01-01

Beam physics considerations for the stripping foil of the 160 MeV PSB H- injection systems are described, including the arguments for the foil type, thickness, geometry and positioning. The foil performance considerations are described, including expected stripping efficiency, emittance growth, energy straggling, temperature and lifetime. The different beam loss mechanisms are quantified in the context of the aperture limits, operational considerations and collimation requirements.

Vortex wakes of a flapping foil

DEFF Research Database (Denmark)

Schnipper, Teis; Andersen, Anders Peter; Bohr, Tomas

2009-01-01

We present an experimental study of a symmetric foil performing pitching oscillations in a vertically flowing soap film. By varying the frequency and amplitude of the oscillation we visualize a variety of wakes with up to 46 vortices per oscillation period, including von Karman vortex street...

Model to estimate fractal dimension for ion-bombarded materials

Energy Technology Data Exchange (ETDEWEB)

Hu, A., E-mail: hu77@purdue.edu; Hassanein, A.

2014-03-15

Comprehensive fractal Monte Carlo model ITMC-F (Hu and Hassanein, 2012 [1]) is developed based on the Monte Carlo ion bombardment simulation code, i.e., Ion Transport in Materials and Compounds (ITMC) code (Hassanein, 1985 [2]). The ITMC-F studies the impact of surface roughness on the angular dependence of sputtering yield. Instead of assuming material surfaces to be flat or composed of exact self-similar fractals in simulation, we developed a new method to describe the surface shapes. Random fractal surfaces which are generated by midpoint displacement algorithm and support vector machine algorithm are combined with ITMC. With this new fractal version of ITMC-F, we successfully simulated the angular dependence of sputtering yield for various ion-target combinations, with the input surface roughness exponent directly depicted from experimental data (Hu and Hassanein, 2012 [1]). The ITMC-F code showed good agreement with the experimental data. In advanced, we compare other experimental sputtering yield with the results from ITMC-F to estimate the surface roughness exponent for ion-bombarded material in this research.

Charge-state-distributions of foil-excited heavy Rydberg atoms

International Nuclear Information System (INIS)

Faibis, A.; Kanter, E.P.; Koenig, W.; Zabransky, B.J.

1985-01-01

Studies of foil-excited fast (MeV/amu) heavy ions have demonstrated large yields of high Rydberg atoms formed in such beams. Further experiments have suggested a strong target-thickness dependence of the yields of such atoms. These results have been puzzling in view of the supposed short mean free paths of such atoms in solids. In an effort to better understand these results, the authors have measured the yields of Rydberg atoms (napprox.100-200) in foil-excited 32 S ions at an incident energy of 125 MeV

Bombardment-induced compositional change with alloys, oxides, and oxysalts. 1

International Nuclear Information System (INIS)

Kelly, R.

1989-01-01

A review of the role of surface binding energies in bombardment-induced compositional change with alloys, oxides and oxysalts is presented. The concepts of preferential sputtering and compositional change may or may not coincide; their differences are clarified. 77 refs.; 12 figs.; 4 tabs

Proposals for the heating mechanism of an electron-bombarded body

International Nuclear Information System (INIS)

Geller, R.; Yerouchalmi, F.

1967-01-01

When a thermally isolated target in vacuum is bombarded by an electron beam the target becomes red. In this paper we try a heuristic explanation indicating how the kinetic power of the beam may be transformed into radiation power controlled by Stefan law. (authors) [fr

Process for forming a nickel foil with controlled and predetermined permeability to hydrogen

Science.gov (United States)

Engelhaupt, Darell E.

1981-09-22

The present invention provides a novel process for forming a nickel foil having a controlled and predetermined hydrogen permeability. This process includes the steps of passing a nickel plating bath through a suitable cation exchange resin to provide a purified nickel plating bath free of copper and gold cations, immersing a nickel anode and a suitable cathode in the purified nickel plating bath containing a selected concentration of an organic sulfonic acid such as a napthalene-trisulfonic acid, electrodepositing a nickel layer having the thickness of a foil onto the cathode, and separating the nickel layer from the cathode to provide a nickel foil. The anode is a readily-corrodible nickel anode. The present invention also provides a novel nickel foil having a greater hydrogen permeability than palladium at room temperature.

Process for forming a nickel foil with controlled and predetermined permeability to hydrogen

International Nuclear Information System (INIS)

Engelhaupt, D. E.

1981-01-01

The present invention provides a novel process for forming a nickel foil having a controlled and predetermined hydrogen permeability. This process includes the steps of passing a nickel plating bath through a suitable cation exchange resin to provide a purified nickel plating bath free of copper and gold cations, immersing a nickel anode and a suitable cathode in the purified nickel plating bath containing a selected concentration of an organic sulfonic acid such as a napthalene-trisulfonic acid, electrodepositing a nickel layer having the thickness of a foil onto the cathode, and separating the nickel layer from the cathode to provide a nickel foil. The anode is a readilycorrodible nickel anode. The present invention also provides a novel nickel foil having a greater hydrogen permeability than palladium at room temperature

Expectations for the Laguna foil implosion experiments

International Nuclear Information System (INIS)

Greene, A.; Brownell, J.; Caird, R.; Goforth, J.; Price, R.; Trainor, J.

1987-01-01

Building on the results achieved in the Pioneer shot series, the Los Alamos Trailmaster project is embarking on the Laguna foil implosion experiments. In this series a Mark-IX helical generator will be coupled to an explosively formed fuse opening switch, a surface-tracking closing switch, and a vacuum power flow and load chamber. In this paper the system design will be discussed and results from zero-, one-, and two-dimensional MHD simulations will be presented. It is anticipated that the generator will provide more than 10 MA of which ∼5.5 MA will be switched to the 5-cm-radius, 2-cm-high, 250-nm-thick aluminum foil load. This should give rise to a 1 μs implosion with more than 100 kJ of kinetic energy

Magnetic collimation and metal foil filtering for electron range and fluence modulation

International Nuclear Information System (INIS)

Phaisangittisakul, N.; D'Souza, W.D.; Ma Lijun

2004-01-01

We investigated the use of magnetically collimated electron beams together with metal filters for electron fluence and range modulation. A longitudinal magnetic field collimation method was developed to reduce skin dose and to improve the electron beam penumbra. Thin metal foils were used to adjust the energies of magnetically collimated electrons. The effects for different types of foils such as Al, Be, Cu, Pb, and Ti were studied using Monte Carlo calculations. An empirical pencil beam dose calculation model was developed to calculate electron dose distributions under magnetic collimation and foil modulation. An optimization method was developed to produce conformal dose distributions for simulated targets such as a horseshoe-shaped target. Our results show that it is possible to produce an electron depth dose enhancement peak using similar techniques of producing a spread-out Bragg peak. In conclusion, our study demonstrates new aspects of using magnetic collimation and foil filtration for producing fluence and range modulated electron dose distributions

Estimation of thermal insulation performance in multi-layer insulator for liquid helium pipe

International Nuclear Information System (INIS)

Shibanuma, Kiyoshi; Kuriyama, Masaaki; Shibata, Takemasa

1991-01-01

For a multi-layer insulator around the liquid helium pipes for cryopumps of JT-60 NBI, a multi-layer insulator composed of 10 layers, which can be wound around the pipe at the same time and in which the respective layers are in concentric circles by shifting them in arrangement, has been developed and tested. As the result, it was shown that the newly developed multi-layer insulator has better thermal insulation performance than the existing one, i.e. the heat load of the newly developed insulator composed of 10 layers was reduced to 1/3 the heat load of the existing insulator, and the heat leak at the joint of the insulator in longitudinal direction of the pipe was negligible. In order to clarify thermal characteristics of the multi-layer insulator, the heat transfer through the insulator has been analyzed considering the radiation heat transfer by the netting spacer between the reflectors, and the temperature dependence on the emissivities and the heat transmission coefficients of these two components of the insulator. The analytical results were in good agreements with the experimental ones, so that the analytical method was shown to be valid. Concerning the influence of the number of layers and the layer density on the insulation performance of the insulator, analytical results showed that the multi-layer insulator with the number of layer about N = 20 and the layer density below 2.0 layer/mm was the most effective for the liquid helium pipe of a JT-60 cryopump. (author)

Thermal insulating panel

Energy Technology Data Exchange (ETDEWEB)

Hughes, J.T.

1985-09-11

A panel of thermal insulation material has at least one main portion which comprises a dry particulate insulation material compressed within a porous envelope so that it is rigid or substantially rigid and at least one auxiliary portion which is secured to and extends along at least one of the edges of the main portions. The auxiliary portions comprise a substantially uncompressed dry particulate insulation material contained within an envelope. The insulation material of the auxiliary portion may be the same as or may be different from the insulation material of the main portion. The envelope of the auxiliary portion may be made of a porous or a non-porous material. (author).

Effects of low-energy ion beam bombardment on metal oxides

International Nuclear Information System (INIS)

Sullivan, J.L.; Saied, S.O.; Choudhury, T.

1993-01-01

This paper describes a study of Ar ion bombardment damage in metal oxides. In the energy range 1 to 5 keV, preferential oxygen removal and reduction of the oxides was found to depend on ion current density, but to be independent of beam energy. (author)

Propulsive performance of pitching foils with variable chordwise flexibility

Science.gov (United States)

Zeyghami, Samane; Moored, Keith; Lehigh University Team

2017-11-01

Many swimming and flying animals propel themselves efficiently through water by oscillating flexible fins. These fins are not homogeneously flexible, but instead their flexural stiffness varies along their chord and span. Here we seek to evaluate the effect stiffness profile on the propulsive performance of pitching foils. Stiffness profile characterizes the variation in the local fin stiffness along the chord. To this aim, we developed a low order model of a functionally-graded material where the chordwise flexibility is modeled by two torsional springs along the chordline and the stiffness and location of the springs can be varied arbitrarily. The torsional spring structural model is then strongly coupled to a boundary element fluid model to simulate the fluid-structure interactions. Keeping the leading edge kinematics unchanged, we alter the stiffness profile of the foil and allow it to swim freely in response to the resulting hydrodynamic forces. We then detail the dependency of the hydrodynamic performance and the wake structure to the variations in the local structural properties of the foil.

Low-energy ion beam bombardment effect on the plant-cell-envelope mimetic membrane for DNA transfer

International Nuclear Information System (INIS)

Prakrajang, K.; Sangwijit, K.; Anuntalabhochai, S.; Wanichapichart, P.; Yu, L.D.

2012-01-01

This study is a systematic analysis of the mechanisms involved in ion-beam induced DNA transfer, an important application of ion beam biotechnology. Cellulose membranes were used to mimic the plant cell envelope. Ion beams of argon (Ar) or nitrogen (N) at an energy of 25 keV bombarded the cellulose membranes at fluences ranging from 10 15 to 10 16 ions/cm 2 . The damage to the ion-beam-bombarded membranes was characterized using infrared spectroscopy, a micro tensile test and scanning electron microscopy (SEM). Chain scission was the dominant radiation damage type in the membrane. DNA diffusion across the membrane was significantly increased after ion beam bombardment. The increase in DNA transfer is therefore attributed to chain scission, which increases the permeability by increasing the number of pores in the membrane.

Wall insulation system

Energy Technology Data Exchange (ETDEWEB)

Kostek, P.T.

1987-08-11

In a channel specially designed to fasten semi-rigid mineral fibre insulation to masonry walls, it is known to be constructed from 20 gauge galvanized steel or other suitable material. The channel is designed to have pre-punched holes along its length for fastening of the channel to the drywall screw. The unique feature of the channel is the teeth running along its length which are pressed into the surface of the butted together sections of the insulation providing a strong grip between the two adjacent pieces of insulation. Of prime importance to the success of this system is the recent technological advancements of the mineral fibre itself which allow the teeth of the channel to engage the insulation fully and hold without mechanical support, rather than be repelled or pushed back by the inherent nature of the insulation material. After the insulation is secured to the masonry wall by concrete nail fastening systems, the drywall is screwed to the channel.

Ultrathin foils used for low-energy neutral atom imaging of the terrestrial magnetosphere

International Nuclear Information System (INIS)

Funsten, H.O.; McComas, D.J.; Barraclough, B.L.

1993-01-01

Magnetospheric imaging by remote detection of low-energy neutral atoms (LENAs) that are created by charge exchange between magnetospheric plasma ions and neutral geocoronal atoms has been proposed as a method to provide global information of magnetospheric dynamics. For LENA detecting, carbon foils can be implemented to (1) ionize the LENAs and electrostatically remove them from the large background of solar UV scattered by the geocorona to which LENA detectors (e.g., microchannel plates) are sensitive and (2) generate secondary electrons to provide coincidence and/or LENA trajectory information. Quantification of LENA-foil interactions are crucial in defining LENA imager performance. The authors present equilibrium charge state distributions due to foil contamination from exposure to air. Angular scattering that results from the projectile-foil interaction is quantified and is shown to be independent of the charge state distribution

Electroplating fission-recoil barriers onto LEU-metal foils for 99Mo-production targets

International Nuclear Information System (INIS)

Smaga, J.A.; Sedlet, J.; Conner, C.; Liberatore, M.W.; Walker, D.E.; Wygmans, D.G.; Vandegrift, G.F.

1997-01-01

Electroplating experiments on uranium foil have been conducted in order to develop low-enriched uranium composite targets suitable for the production of 99 Mo. Preparation of the foil surface prior to plating was found to play a key role in the quality of the resultant coating. A surface preparation procedure was developed that produces both zinc and nickel coatings with the desired level of coating adherence and coverage. Modifications of the existing plating processes now need investigation to improve to uniformity of the plating thickness, especially at the foil perimeter. (author)

Electroplating fission-recoil barriers onto LEU-metal foils for 99Mo-production targets

International Nuclear Information System (INIS)

Smaga, J.A.; Sedlet, J.; Conner, C.; Liberatore, M.W.; Walker, D.E.; Wygmans, D.G.; Vandegrift, G.F.

1997-10-01

Electroplating experiments on uranium foil have been conducted in order to develop low-enriched uranium composite targets suitable for the production of 99 Mo. Preparation of the foil surface prior to plating was found to play a key role in the quality of the resultant coating. A surface preparation procedure was developed that produces both zinc and nickel coatings with the desired level of coating adherence and coverage. Modifications of the existing plating processes now need investigation to improve to uniformity of the plating thickness, especially at the foil perimeter

The timeline of the lunar bombardment: Revisited

Science.gov (United States)

Morbidelli, A.; Nesvorny, D.; Laurenz, V.; Marchi, S.; Rubie, D. C.; Elkins-Tanton, L.; Wieczorek, M.; Jacobson, S.

2018-05-01

The timeline of the lunar bombardment in the first Gy of Solar System history remains unclear. Basin-forming impacts (e.g. Imbrium, Orientale), occurred 3.9-3.7 Gy ago, i.e. 600-800 My after the formation of the Moon itself. Many other basins formed before Imbrium, but their exact ages are not precisely known. There is an intense debate between two possible interpretations of the data: in the cataclysm scenario there was a surge in the impact rate approximately at the time of Imbrium formation, while in the accretion tail scenario the lunar bombardment declined since the era of planet formation and the latest basins formed in its tail-end. Here, we revisit the work of Morbidelli et al. (2012) that examined which scenario could be compatible with both the lunar crater record in the 3-4 Gy period and the abundance of highly siderophile elements (HSE) in the lunar mantle. We use updated numerical simulations of the fluxes of asteroids, comets and planetesimals leftover from the planet-formation process. Under the traditional assumption that the HSEs track the total amount of material accreted by the Moon since its formation, we conclude that only the cataclysm scenario can explain the data. The cataclysm should have started ∼ 3.95 Gy ago. However we also consider the possibility that HSEs are sequestered from the mantle of a planet during magma ocean crystallization, due to iron sulfide exsolution (O'Neil, 1991; Rubie et al., 2016). We show that this is likely true also for the Moon, if mantle overturn is taken into account. Based on the hypothesis that the lunar magma ocean crystallized about 100-150 My after Moon formation (Elkins-Tanton et al., 2011), and therefore that HSEs accumulated in the lunar mantle only after this timespan, we show that the bombardment in the 3-4 Gy period can be explained in the accretion tail scenario. This hypothesis would also explain why the Moon appears so depleted in HSEs relative to the Earth. We also extend our analysis of the

Destruction of metallic foils under laser radiation

International Nuclear Information System (INIS)

Khokhlov, N.P.; Lisitsyn, Yu.V.; Mineev, V.N.; Ivanov, A.G.

1975-01-01

Experimental results are presented which illustrate the process of destruction of aluminium, lead and tantalum foils under irradiation of a neodymium laser, working in free generation regime with a power density varying from 5.10 5 - 5.10 6 wt/sq.cm. Calorimeters and photocells sensitive to the radiation with lambda=1.06 have been used for measuring the energy and recording the shape of the radiation pulse incident onto the target and passing through the disintegration products. The weight of the target has been determined prior to and after the experiment to find out the weight of Δm material expelled from the target. Rates of product scattering and a target destruction period, an amount of the material expelled and parameters of the radiation passing through the disintegration products have been determined as a function of the power density and an angle of the radiation incidence on the surface of the specimens. Average densities and absorption coefficients of the disintegration products of the foils under study have been assessed. A comparison of the characteristics of the metal foil (t 1 j) destruction in Pb-Ta-Al series with the metal thermal properties in this series shows that the destruction characteristics periodically vary as heat capacity, thermal conduction, evaporation heat and melting heat alter. A period of the target destruction becomes longer and the expelled mass smaller as the aforesaid thermal properties of the metals in Pb-Ta-Al series intensity [ru

Micron-scale resolution radiography of laser-accelerated and laser-exploded foils using an yttrium x-ray laser

International Nuclear Information System (INIS)

Cauble, R.; Da Silva, L.B.; Barbee, T.W. Jr.; Celliers, P.; Moreno, J.C.; Mrowka, S.; Perry, T.S.; Wan, A.S.

1994-09-01

The authors have imaged laser-accelerated foils and exploding foils on the few-micron scale using an yttrium x-ray laser (155 angstrom, 80 eV, ∼200 ps duration) and a multilayer mirror imaging system. At the maximum magnification of 30, resolution was of order one micron. The images were side-on radiographs of the foils. Accelerated foils showed significant filamentation on the rear-side (away from the driving laser) of the foil, although the laser beam was smoothed. In addition to the narrow rear-side filamentation, some shots revealed larger-scale plume-like structures on the front (driven) side of the Al foil. These plumes seem to be little-affected by beam smoothing and are likely a consequence of Rayleigh-Taylor instability. The experiments were carried out at the Nova two-beam facility

Peculiarities of phase transformations in molybdenum-silicon system under ion bombardment

International Nuclear Information System (INIS)

Gurskij, L.I.; Zelenin, V.A.; Bobchenok, Yu.L.

1984-01-01

The problems of effect of ion bombardment and thermal treatment on the mechanisms of formation of transition layers and structural transformations in the molybdenum-silicon system, where the interface is subjected to ion bombardment through a film of molybdenum, are considered. The method of electron diffraction analysis has been applied to establish that at the molybdenum-silicon interface a transitional region appears during irradiation which has a semiamorphous structure at the doses up to 8x10 14 ion/cm 2 , while at higher doses it transforms into polycrystalline intermediate layer which consists of MoB and the compound close in composition to MoSisub(0.65). Due to thermal treatment for 60873 K a large-grain phase (Mo 3 Si+MoSi 2 ) appears in the transition layer below which a large-grain silicon layer is placed

Thrombogenicity tests on ar-irradiated polycarbonate foils

Energy Technology Data Exchange (ETDEWEB)

Trindade, Gustavo F.; Rizzutto, Marcia A.; Silva, Tiago F.; Moro, Marcos V.; Added, Nemitala; Tabacniks, Manfredo H., E-mail: g.ferraz@usp.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Inst. de Fisica; Delgado, Adriana O. [Universidade Federal de Sao Carlos (UFSCAR), Sorocaba, SP (Brazil); Cunha, Tatiana F. [Biosintesis P and D do Brasil, Sao Paulo, SP (Brazil); Higa, Olga Z. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Biotecnologia

2013-07-01

Understanding polymer surface properties is extremely important for the most wide range of their applications, from basic coating to the most complex composites and biomaterials. Low energy ion beam irradiation of polymer can improve such surface properties. By modifying its surface biocompatibility, polymers are excellent candidates for biomaterials, due to its malleability and low weight, when compared to metals. In this work, we irradiated 30-μm Bisphenol-A Polycarbonate foils with 23-keV Argon ion beam at six different doses. Aluminium foils were simultaneously irradiated in order to measure the doses by Rutherford Backscattering Spectroscopy. The surface modifications after the argon ion beam irradiation were analyzed by water contact angle measurements and atomic force microscopy. Platelet adhesion tests were used in order to investigate thrombogenicity, showing a growing tendency with the irradiated Argon dose. (author)

Thrombogenicity tests on ar-irradiated polycarbonate foils

International Nuclear Information System (INIS)

Trindade, Gustavo F.; Rizzutto, Marcia A.; Silva, Tiago F.; Moro, Marcos V.; Added, Nemitala; Tabacniks, Manfredo H.; Cunha, Tatiana F.; Higa, Olga Z.

2013-01-01

Understanding polymer surface properties is extremely important for the most wide range of their applications, from basic coating to the most complex composites and biomaterials. Low energy ion beam irradiation of polymer can improve such surface properties. By modifying its surface biocompatibility, polymers are excellent candidates for biomaterials, due to its malleability and low weight, when compared to metals. In this work, we irradiated 30-μm Bisphenol-A Polycarbonate foils with 23-keV Argon ion beam at six different doses. Aluminium foils were simultaneously irradiated in order to measure the doses by Rutherford Backscattering Spectroscopy. The surface modifications after the argon ion beam irradiation were analyzed by water contact angle measurements and atomic force microscopy. Platelet adhesion tests were used in order to investigate thrombogenicity, showing a growing tendency with the irradiated Argon dose. (author)

Erosion of Be and deposition of C and O due to bombardment with C{sup +} and CO{sup +}

Energy Technology Data Exchange (ETDEWEB)

Eckstein, W.; Goldstrass, P.; Linsmeier, Ch. [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany)

1998-01-01

The bombardment of Be with 3 and 5 keV C{sup +} and CO{sup +} at normal incidence is investigated experimentally and by computer simulation with the program TRIDYN. The deposited amount of C and O is determined experimentally and found in good agreement with calculated data for C bombardment. Chemical erosion dominates at higher fluences for CO{sup +} bombardment. Calculations are then used to determine the sputter yield of Be at steady state conditions as a function of the plasma edge electron temperature for two C impurity concentrations in the incident D flux, typical for fusion plasmas. The fluence to reach steady state conditions is also investigated. (author)

Spatial variation in void volume during charged particle bombardment: the effects of injected interstitials

International Nuclear Information System (INIS)

Lee, E.H.; Mansur, L.K.; Yoo, M.H.

1979-01-01

Experimental observations of the void volume at several depths along the range of 4 MeV Ni ions in 316 stainless steel are reported. The specimens were first preconditioned by neutron irradiation at temperatures of 450 and 584 0 C to fluences of approximately 8 x 10 26 n/m -2 . The void volume after ion bombardment to 60 dpa at the peak damage depth is significantly lower at the peak damage depth than in the region between that and the free surface. The ratio of the step height to void volume at the depth of peak energy deposition between regions masked from and exposed to the beam is strongly dependent on bombardment temperature. The reduction of void volume near the peak damage depth is larger for the 584 0 C than for the 450 0 C preconditioned material. These observations are consistent with recent theoretical results which account for the injection of the bombarding ions as self-interstitials. The theory necessary to understand the effect is developed

Reduction of heat insulation upon soaking of the insulation layer

Science.gov (United States)

Achtliger, J.

1983-09-01

Improved thermal protection of hollow masonry by introduction of a core insulation between the inner and outer shell is discussed. The thermal conductivity of insulation materials was determined in dry state and after soaking by water with different volume-related moisture contents. The interpolated thermal conductivity values from three measured values at 10 C average temperature are presented as a function of the pertinent moisture content. Fills of expanded polystyrene, perlite and granulated mineral fibers, insulating boards made of mineral fibers and in situ cellular plastics produced from urea-formaldehyde resin were investigated. Test results show a confirmation of thermal conductivity values for insulating materials in hollow masonry.

Simulation of turn-by-turn passage of protons through the H-minus stripping foil in booster

Energy Technology Data Exchange (ETDEWEB)

Gardner, C. [Brookhaven National Lab. (BNL), Upton, NY (United States)

2017-07-06

Equations for transverse emittance growth due to multiple passes of circulating proton beam through the H-minus stripping foil in Booster were developed in [1]. These were based on simple principles of statistics and simple assumptions about the initial distribution of particles incident on the foil. It was assumed there that the foil dimensions and position of the incoming beam are such that all particles hit the foil on every turn around the machine. In the present note we assume only that all incoming H-minus ions from Linac hit the foil and are stripped of their electrons. The resulting protons circulate indefinitely around the machine. Setups in which the foil width is reduced so that not all protons hit the foil on every turn are studied here by simulation. The aim is to determine the effectiveness of such setups in reducing the emittance growth of circulating proton beam during the injection of H-minus beam. The simulations also serve as a check of the equations developed in [1], and vice versa. The particulars of the simulation setup are given in Sections 1 through 11. Figures 1 through 12 show simulation results for the case in which all particles hit the foil on every turn. The results are in good agreement with those obtained from the equations of reference [1]. Figures 13 through 19 show simulation results for various setups in which the foil width is reduced. These results are summarized in Section 12. In all gures the horizontal axis gives the turn number. The unit of the vertical axis is micrometers ( m) in all plots of emittance.

Foil Panel Mirrors for Nonimaging Applications

Science.gov (United States)

Kuyper, D. J.; Castillo, A. A.

1984-01-01

Large durable, lightweight mirrors made by bonding thick aluminum foil to honeycomb panels or other rigid, flat backings. Mirrors suitable for use as infrared shields, telescope doors, solar-furnance doors, advertising displays, or other reflectors that require low thermal emissivity and high specularity but do not require precise surface figure necessary for imaging.

Electron emission from Inconel under ion bombardment

International Nuclear Information System (INIS)

Alonso, E.V.; Baragiola, R.A.; Ferron, J.; Oliva-Florio, A.

1979-01-01

Electron yields from clean and oxidized Inconel 625 surfaces have been measured for H + ,H 2 + ,He + ,O + and Ar + ions at normal incidence in the energy range 1.5 to 40 keV. These measurements have been made under ultrahigh vacuum and the samples were freed of surface contaminants by bombarding with high doses of either 20 keV H 2 + or 30 keV Ar + ions. Differences in yields of oxidized versus clean surfaces are explained in terms of differences in the probability that electrons internally excited escape upon reaching the surface. (author)

Optimization of electron beam crosslinking of wire and cable insulation

International Nuclear Information System (INIS)

Zimek, Z.; Przybytniak, G.; Nowicki, A.

2011-01-01

Complete text of publication follows. The computer simulations based on Monte Carlo method and the ModeCEB software program were carried out in connection with EB radiation set-up for crosslinking of electrical wire and cable insulation, located at the Center for Radiation Research and Technology of the Institute of Nuclear Chemistry and Technology. The theoretical predictions for absorbed dose distribution in irradiated electrical wire and cable insulation caused by scanned EB were compared to the experimental results of irradiation which were carried out in the experimental set-up based on ILU 6 electron accelerator, which is characterized by the following parameters: Electron energy 0.5-2.0 MeV; Average beam current 40-10 mA, pulse duration 400 μs; Width of scanning up to 80 cm; Scan frequency up to 50 Hz. The computer simulation of the dose distributions in two-sided irradiation system by a scanned electron beam in multilayer circular objects was performed for different process parameters; electrical wire and cable geometry (thickness of insulation layers and cupper wire diameter), type of polymer isolation, electron energy, energy spread, geometry of electron beam and electrical wire and cable distribution at irradiation zone. The geometry of electron beam distribution in irradiation zone was measured using TVA and PVC foil dosimeters for electron energy range available in ILU 6 accelerator. The temperature rise of irradiated electrical wire and irradiation homogeneity were evaluated for different experimental conditions to optimize process parameters. The obtained results of computer simulation were supported by experimental data of dose distribution based on gel-fraction measurements. Such agreement indicates that computer simulation ModeCEB is correct and sufficient for modelling of absorbed dose distribution in multi-layer circular objects irradiated with scanned electron beams. Acknowledgement: The R and D activities are supported by the European

Foil deposition alpha collector probe for TFTR's D-T phase

International Nuclear Information System (INIS)

Hermann, H.W.; Darrow, D.S.; Timberlake, J.; Zweben, S.J.; Chong, G.P.; Pitcher, C.S.; Macaulay-Newcombe, R.G.

1995-03-01

A new foil deposition alpha collector sample probe has been developed for TFTR's D-T phase. D-T fusion produced alpha particles escaping from the plasma are implanted in nickel foils located in a series of collimating ports on the detector. The nickel foils are removed from the tokamak after exposure to one or more plasma discharges and analyzed for helium content. This detector is intended to provide improved alpha particle energy resolution and pitch angle coverage over existing lost alpha detectors, and to provide an absolutely calibrated cross-check with these detectors. The ability to resolve between separate energy components of alpha particle loss is estimated to be ∼ 20%. A full 360 degree of pitch angle coverage is provided for by 8 channels having an acceptance range of ∼ 53 degree per channel. These detectors will be useful in characterizing classical and anomalous alpha losses and any collective alpha instabilities that may be excited during the D-T campaign of TFTR

Zika Vaccine Development: Flavivirus Foils

Science.gov (United States)

2016-09-01

Martins, Bavari, Zika Vaccine Development 1 Zika Vaccine Development: Flavivirus Foils Martins KAO, Bavari S. The current Zika virus...States government. The rapid response to Zika is perhaps the first of its kind, and it undoubtedly has been made possible by the lessons learned from...the response to the 2014 Ebola virus outbreak in West Africa. However, Zika virus is not Ebola virus. As of February 2016 there were only 296

Low-energy ion beam bombardment effect on the plant-cell-envelope mimetic membrane for DNA transfer

Energy Technology Data Exchange (ETDEWEB)

Prakrajang, K., E-mail: k.prakrajang@gmail.com [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Sangwijit, K.; Anuntalabhochai, S. [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Wanichapichart, P. [Membrane Science and Technology Research Center, Department of Physics, Faculty of Science, Prince of Songkla University, Hat Yai, Songkla 90112 (Thailand); Yu, L.D., E-mail: yuld@fnrf.science.cmu.ac.th [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

2012-09-01

This study is a systematic analysis of the mechanisms involved in ion-beam induced DNA transfer, an important application of ion beam biotechnology. Cellulose membranes were used to mimic the plant cell envelope. Ion beams of argon (Ar) or nitrogen (N) at an energy of 25 keV bombarded the cellulose membranes at fluences ranging from 10{sup 15} to 10{sup 16} ions/cm{sup 2}. The damage to the ion-beam-bombarded membranes was characterized using infrared spectroscopy, a micro tensile test and scanning electron microscopy (SEM). Chain scission was the dominant radiation damage type in the membrane. DNA diffusion across the membrane was significantly increased after ion beam bombardment. The increase in DNA transfer is therefore attributed to chain scission, which increases the permeability by increasing the number of pores in the membrane.

Numerical simulation of the pressure pulses produced by a pressure screen foil rotor

International Nuclear Information System (INIS)

Feng, M.; Ollivier-Gooch, C.; Gooding, R.W.; Olson, J.A.

2003-01-01

Pressure screening is the most industrially efficient and effective means of removing contaminants that degrade the appearance and strength of paper and fractionating fibres for selective treatments and specialty products. A critical design component of a screen is the rotor which produces pressure pulses on the screen cylinder surface to keep the screening apertures clear. To understand the effect of the key design and operating variables for a NACA 0012 foil rotor, a computational fluid dynamic (CFD) simulation tool was developed with FLUENT software, and the numerical results were compared with experimental measurements. The computational results of pressure pulses were shown to be in good agreement with experimental pressure measurements over a wide range of foil tip-speeds, clearances and angles of attack. In addition, it was shown that the magnitude of the pressure pulse peak increases as the rotating speed increases linearly with the square of tip-speed for all the angles of attack studied. The maximum negative pressure pulse occurred for the foil at 5 degrees angle of attack. Flow began to separate from foil surface near the screen plate beyond 10 degrees angle of attack. The positive pressure peak near the leading edge of the foil is completely eliminated for foils operating at a positive angle of attack. The magnitude of the negative pressure peak increased as clearance decreased. In addition to, and more important than, these specific results, we have shown that CFD is a viable tool for the optimal design and operation of rotors in industrial pressure screens. (author)

Nanodiamond Foils for H- Stripping to Support the Spallation Neutron Source (SNS) and Related Applications

Energy Technology Data Exchange (ETDEWEB)

Vispute, R D [Blue Wave Semiconductors; Ermer, Henry K [Blue Wave Semiconductors; Sinsky, Phillip [Blue Wave Semiconductors; Seiser, Andrew [Blue Wave Semiconductors; Shaw, Robert W [ORNL; Wilson, Leslie L [ORNL; Harris, Gary [Howard University; Piazza, Fabrice [Pontifica Universidad Catolica Madre y Maestra, Dominican Republic

2013-01-01

Thin diamond foils are needed in many particle accelerator experiments regarding nuclear and atomic physics, as well as in some interdisciplinary research. Particularly, nanodiamond texture is attractive for this purpose as it possesses a unique combination of diamond properties such as high thermal conductivity, mechanical strength and high radiation hardness; therefore, it is a potential material for energetic ion beam stripper foils. At the ORNL Spallation Neutron Source (SNS), the installed set of foils must be able to survive a nominal five-month operation period, without the need for unscheduled costly shutdowns and repairs. Thus, a single nanodiamond foil about the size of a postage stamp is critical to the entire operation of SNS and similar sources in U.S. laboratories and around the world. We are investigating nanocrystalline, polycrystalline and their admixture films fabricated using a hot filament chemical vapor deposition (HFCVD) system for H- stripping to support the SNS at Oak Ridge National Laboratory. Here we discuss optimization of process variables such as substrate temperature, process gas ratio of H2/Ar/CH4, substrate to filament distance, filament temperature, carburization conditions, and filament geometry to achieve high purity diamond foils on patterned silicon substrates with manageable intrinsic and thermal stresses so that they can be released as free standing foils without curling. An in situ laser reflectance interferometry tool (LRI) is used for monitoring the growth characteristics of the diamond thin film materials. The optimization process has yielded free standing foils with no pinholes. The sp3/sp2 bonds are controlled to optimize electrical resistivity to reduce the possibility of surface charging of the foils. The integrated LRI and HFCVD process provides real time information on the growth of films and can quickly illustrate growth features and control over film thickness. The results are discussed in the light of development

A convenient way to double the capacity of a NEC type foil stripper

International Nuclear Information System (INIS)

Chapman, K.R.

1988-01-01

A convenient method is described to increase the capacity of a NEC type terminal stripper. This renders the necessity for tank entry to renew foils less frequent. This is especially useful when the use of heavy ion beams renders foil lifetimes very short. (orig.)

Influence of UV and Gamma radiations on the induced birefringence of stretched poly(vinyl) alcohol foils

Science.gov (United States)

Nechifor, Cristina-Delia; Zelinschi, Carmen Beatrice; Dorohoi, Dana-Ortansa

2014-03-01

The aim of our paper is to evidence the influence of Gamma and UV radiations on the induced birefringence of poly(vinyl alcohol) stretched foils. Thin foils of PVA were prepared and dried without modifying their surfaces. The polymeric foils were irradiated from 15 min to 6 h using UV and Gamma radiations. The induced by stretching under heating birefringence of PVA films was measured at λ = 589.3 nm with a Babinet Compensator. Physico-chemical processes (photo stabilization, photo degradation, oxidation) induced by irradiation of polymer matrix influence both the stretching degree and the anisotropy of etired foils. An increase of birefringence versus the stretching ratio of the PVA foils was evidenced for all studied samples. The dependence of the birefringence on the exposure time, stretching ratio and nature of radiation was also confirmed.

Fast atom bombardment mass spectrometry of condensed tannin sulfonate derivatives

Science.gov (United States)

J.J. Karchesy; L.Y. Foo; Richard W. Hemingway; E. Barofsky; D.F. Barofsky

1989-01-01

Condensed tannin sulfonate derivatives were studied by fast atom bombardment mass spectrometry (FAB-MS) to assess the feasibility of using this technique for determining molecular weight and structural information about these compounds. Both positive- and negative-ion spectra provided useful data with regard to molecular weight, cation species present, and presence of...

Applying a foil queue micro-electrode in micro-EDM to fabricate a 3D micro-structure

Science.gov (United States)

Xu, Bin; Guo, Kang; Wu, Xiao-yu; Lei, Jian-guo; Liang, Xiong; Guo, Deng-ji; Ma, Jiang; Cheng, Rong

2018-05-01

Applying a 3D micro-electrode in a micro electrical discharge machining (micro-EDM) can fabricate a 3D micro-structure with an up and down reciprocating method. However, this processing method has some shortcomings, such as a low success rate and a complex process for fabrication of 3D micro-electrodes. By focusing on these shortcomings, this paper proposed a novel 3D micro-EDM process based on the foil queue micro-electrode. Firstly, a 3D micro-electrode was discretized into several foil micro-electrodes and these foil micro-electrodes constituted a foil queue micro-electrode. Then, based on the planned process path, foil micro-electrodes were applied in micro-EDM sequentially and the micro-EDM results of each foil micro-electrode were able to superimpose the 3D micro-structure. However, the step effect will occur on the 3D micro-structure surface, which has an adverse effect on the 3D micro-structure. To tackle this problem, this paper proposes to reduce this adverse effect by rounded corner wear at the end of the foil micro-electrode and studies the impact of machining parameters on rounded corner wear and the step effect on the micro-structure surface. Finally, using a wire cutting voltage of 80 V, a current of 0.5 A and a pulse width modulation ratio of 1:4, the foil queue micro-electrode was fabricated by wire electrical discharge machining. Also, using a pulse width of 100 ns, a pulse interval of 200 ns, a voltage of 100 V and workpiece material of 304# stainless steel, the foil queue micro-electrode was applied in micro-EDM for processing of a 3D micro-structure with hemispherical features, which verified the feasibility of this process.

Effect of foil orientation on damage accumulation during irradiation in magnesium and annealing response of dislocation loops

International Nuclear Information System (INIS)

Khan, A.K.; Yao, Z.; Daymond, M.R.; Holt, R.A.

2012-01-01

Highlights: ► Effect of foil orientation on electron irradiation damage in Mg is analyzed. ► Prism plane defects increases in prism foils as compared to basal foils. ► Basal faults were interstitial and prism plane defects were mixed in character. ► Shrinkage of interstitial dislocations takes place by the self diffusion mechanism. - Abstract: The effect of foil orientation on damage accumulation behavior in commercial purity magnesium is investigated by in situ electron and ion irradiation. Transmission electron microscope has been used to study the dislocation loops formed by the agglomeration of point defects during irradiation. It has been observed that the ratio of prism plane to basal plane defects increases as the foil orientation is changed from basal to the prism foil. The ratio of vacancy to interstitial defects also increases in prism foils as compared to the basal foils. This point defect accumulation behavior is reversed when magnesium is irradiated with 1 MeV Kr 2+ ions and the formation of basal plane dislocation loops were only observed in prism foils and did not take place in the basal foils. Analysis showed that all the basal plane dislocation loops have Burgers vector of the type 1/(6〈202 ¯ 3〉) and are interstitial in nature whereas prism plane dislocation loops have Burgers vector of the type 1/(3〈112 ¯ 0〉) and are of mixed interstitial/vacancy in character. In situ annealing experiments at different temperatures performed on electron irradiated magnesium foils suggest that those dislocation loops that become thermodynamically unstable anneal out in a matter of few seconds whereas other stable dislocation loops continue to shrink by absorbing surrounding vacancy clusters. The activation energy for the shrinkage of the interstitial dislocation loops has been derived and the results show that the shrinkage of interstitial dislocation loops takes place by the mechanism of vacancy assisted self diffusion.

The Chevron Foil Thrust Bearing: Improved Performance Through Passive Thermal Management and Effective Lubricant Mixing

Science.gov (United States)

Bruckner, Robert

2013-01-01

An improved foil thrust bearing is described that eliminates or reduces the need for forced cooling of the bearing foils while at the same time improves the load capacity of the bearing, enhances damping, provides overload tolerance, and eliminates the high speed load capacity drop-off that plagues the current state of the art. The performance improvement demonstrated by the chevron foil thrust bearing stems from a novel trailing edge shape that splays the hot lubricant in the thin film radially, thus preventing hot lubricant carry-over into the ensuing bearing sector. Additionally, the chevron shaped trailing edge induces vortical mixing of the hot lubricant with the gas that is naturally resident within the inter-pad region of a foil thrust bearing. The elimination of hot gas carry-over in combination with the enhanced mixing has enabled a completely passive thermally managed foil bearing design. Laboratory testing at NASA has confirmed the original analysis and reduced this concept to practice.

Composite metal foil and ceramic fabric materials

Science.gov (United States)

Webb, Brent J.; Antoniak, Zen I.; Prater, John T.; DeSteese, John G.

1992-01-01

The invention comprises new materials useful in a wide variety of terrestrial and space applications. In one aspect, the invention comprises a flexible cloth-like material comprising a layer of flexible woven ceramic fabric bonded with a layer of metallic foil. In another aspect, the invention includes a flexible fluid impermeable barrier comprising a flexible woven ceramic fabric layer having metal wire woven therein. A metallic foil layer is incontinuously welded to the woven metal wire. In yet another aspect, the invention includes a material comprising a layer of flexible woven ceramic fabric bonded with a layer of an organic polymer. In still another aspect, the invention includes a rigid fabric structure comprising a flexible woven ceramic fabric and a resinous support material which has been hardened as the direct result of exposure to ultraviolet light. Inventive methods for producing such material are also disclosed.

Propagation Characteristics of Multilayer Hybrid Insulator-Metal-Insulator and Metal-Insulator-Metal Plasmonic Waveguides

Directory of Open Access Journals (Sweden)

M. Talafi Noghani

2014-02-01

Full Text Available Propagation characteristics of symmetrical and asymmetrical multilayer hybrid insulator-metal-insulator (HIMI and metal-insulator-metal (HMIM plasmonic slab waveguides are investigated using the transfer matrix method. Propagation length (Lp and spatial length (Ls are used as two figures of merit to qualitate the plasmonic waveguides. Symmetrical structures are shown to be more performant (having higher Lp and lower Ls, nevertheless it is shown that usage of asymmetrical geometry could compensate for the performance degradation in practically realized HIMI waveguides with different substrate materials. It is found that HMIM slab waveguide could support almost long-range subdiffraction plasmonic modes at dimensions lower than the spatial length of the HIMI slab waveguide.

Study of nuclear tracks on different polycarbonate foils and their feasibility for use in personnel monitoring

International Nuclear Information System (INIS)

Jayalakshmi, V.; Rohatgi, Rupali; Sathian, Deepa; Marathe, P.K.; Nair, Sarala; Chourasiya, G.; Kannan, S.

2009-01-01

CR-39 (PDAC) a solid state nuclear track detector, is used as a routine personnel monitor. 1800 workers are being monitored quarterly for fast neutron using CR-39 foils. These foils procured from Pershore Mouldings, UK are very expensive and indigenous development will make the foils cost effective. The aim of this paper is to find a suitable alternative to the imported CR-39 foils for use in personnel monitoring. The foils from three different manufacturers have been compared with CR-39 foils from Pershore Moulding, UK, presently in use. Out of the three, only sample no 1 is promising. It has a background and sensitivity comparable with CR-39 presently used. The sample 2 is CR-39 being developed in India, has a relatively high background and poor sensitivity. Efforts are being made to improve the quality of this sample. The sample 3 was a poly carbonate from local manufacturer which produced very few tracks and the standard deviation of track counts was very large and hence not useful for personnel monitoring. (author)

Mechanism of conductivity type conversion in p-Hg1-xCdxTe crystals under low energy ion bombardment

International Nuclear Information System (INIS)

Bogoboyashchij, V.V.; Izhnin, I.I.

2000-01-01

Conditions giving rise to accelerated diffusion of Hg under bombardment of p-Hg 1-x Cd x Te by low-energy particles are analyzed and probable mechanisms of the phenomenon are suggested, permitting qualitative and quantitative agreement with experimental data. Analysis indicates that basic regularities of p-n-conversion during Hg 0.8 Cd 0.2 Te crystal bombardment by neutralized ions can be easily explained in the framework of traditional notions of mercury chemical diffusion in this material. The regularities stem from specific features of defect formation in Hg 0.8 Cd 0.2 Te, on the one hand, and from a high concentration of intrinsic electrons and holes, screening effectively the defective layer electric field, on the other hand. The high rate of conversion during ion bombardment compared with the rate of conversion during annealing in mercury vapors can be explained by the fact that a great number of nonequilibrium interstitial atoms of mercury, by far exceeding the value during thermal annealing, is crated near the surface of the crystal bombarded [ru

Slowing down of 100 keV antiprotons in Al foils

Directory of Open Access Journals (Sweden)

K. Nordlund

2018-03-01

Full Text Available Using energy degrading foils to slow down antiprotons is of interest for producing antihydrogen atoms. I consider here the slowing down of 100 keV antiprotons, that will be produced in the ELENA storage ring under construction at CERN, to energies below 10 keV. At these low energies, they are suitable for efficient antihydrogen production. I simulate the antihydrogen motion and slowing down in Al foils using a recently developed molecular dynamics approach. The results show that the optimal Al foil thickness for slowing down the antiprotons to below 5 keV is 910 nm, and to below 10 keV is 840 nm. Also the lateral spreading of the transmitted antiprotons is reported and the uncertainties discussed. Keywords: Antiprotons, Stopping power, Slowing down, Molecular dynamics

Comparison of EXAFS Foil Spectra from Around the World

International Nuclear Information System (INIS)

Kelly, S.D.; Bare, S.R.; Greenlay, N.; Azevedo, G.; Balasubramanian, M.; Barton, D.; Chattopadhyay, S.; Fakra, S.; Johannessen, B.; Newville, M.; Pena, J.; Pokrovski, G.S; Proux, O.; Priolkar, K.; Ravel, B.; Webb, S.M.

2010-01-01

The EXAFS spectra of Cu and Pd foil from many different beamlines and synchrotrons are compared to address the dependence of the amplitude reduction factor (S 0 2 ) on beamline specific parameters. Even though S 0 2 is the same parameter as the EXAFS coordination number, the value for S 0 2 is given little attention, and is often unreported. The S 0 2 often differs for the same material due to beamline and sample attributes, such that no importance is given to S 0 2 -values within a general range of 0.7 to 1.1. EXAFS beamlines have evolved such that it should now be feasible to use standard S 0 2 values for all EXAFS measurements of a specific elemental environment. This would allow for the determination of the imaginary energy (Ei) to account for broadening of the EXAFS signal rather than folding these errors into an effective S 0 2 -value. To test this concept, we model 11 Cu-foil and 6 Pd-foil EXAFS spectra from around the world to compare the difference in S 0 2 - and Ei-values.

Large area flexible lighting foils using distributed bare LED dies on polyester substrates

NARCIS (Netherlands)

Ende, D.A. van den; Kusters, R.H.L.; Cauwe, M.; Waal, A. van der; Brand, J. van den

2013-01-01

Integration of LEDs on flexible foil substrates is of interest for flexible lighting applications and for backlights for flexible displays. Such a large area lighting device can be made by integrating a matrix of closely spaced LEDs on a flexible foil substrate. Preferably, these LEDs are integrated

Cesium ion bombardment of metal surfaces

International Nuclear Information System (INIS)

Tompa, G.S.

1986-01-01

The steady state cesium coverage due to cesium ion bombardment of molybdenum and tungsten was studied for the incident energy range below 500 eV. When a sample is exposed to a positive ion beam, the work function decreases until steady state is reached with a total dose of less than ≅10 16 ions/cm 2 , for both tungsten and molybdenum. A steady state minimum work function surface is produced at an incident energy of ≅100 eV for molybdenum and at an incident energy of ≅45 eV for tungsten. Increasing the incident energy results in an increase in the work function corresponding to a decrease in the surface coverage of cesium. At incident energies less than that giving the minimum work function, the work function approaches that of cesium metal. At a given bombarding energy the cesium coverage of tungsten is uniformly less than that of molybdenum. Effects of hydrogen gas coadsorption were also examined. Hydrogen coadsorption does not have a large effect on the steady state work functions. The largest shifts in the work function due to the coadsorption of hydrogen occur on the samples when there is no cesium present. A theory describing the steady-state coverage was developed is used to make predictions for other materials. A simple sticking and sputtering relationship, not including implantation, cannot account for the steady state coverage. At low concentrations, cesium coverage of a target is proportional to the ratio of (1 - β)/γ where β is the reflection coefficient and γ is the sputter yield. High coverages are produced on molybdenum due to implantation and low backscattering, because molybdenum is lighter than cesium. For tungsten the high backscattering and low implantation result in low coverages

High quality graphene synthesized by atmospheric pressure CVD on copper foil

OpenAIRE

Trinsoutrot, Pierre; Rabot, Caroline; Vergnes, Hugues; Delamoreanu, Alexandru; Zenasni, Aziz; Caussat, Brigitte

2013-01-01

International audience; Graphene was synthesized at 1000 °C by Atmospheric Pressure Chemical Vapor Deposition on copper foil from methane diluted in argon and hydrogen. The influence of the main synthesis parameters was studied on 2 × 2 cm2 foils in order to obtain continuous monolayer graphenewithout crystalline defect. The uniformity, crystal quality and number of layers of graphenewere analyzed by Raman spectroscopy and Scanning Electronic Microscopy. First, an increase of the annealing pr...

Connection factor calculation for isotopic neutron flux measurements with foil detectors

International Nuclear Information System (INIS)

Avila L, J.

1987-01-01

Thermal and resonance neutron self-shielding factors, neutron flux distortion and edge effects as well as a connection factor for neutron flux profile around a foil detector have been calculated. A general expression for resonance self shielding factor is presented in order to take into account the most important resonances for a given isotope. A computer program SPRESYTER.BAS was written and results for In-115 and Au-197 foils are given

Large-area thin self-supporting carbon foils with MgO coatings

Science.gov (United States)

Stolarz, Anna; Maier-Komor, Peter

2002-03-01

Large area self-supporting carbon foils in the thickness of range of 8-22 μg/cm 2, coated with approximately 4 μg/cm 2 MgO have been prepared by e-gun evaporation. They were mounted on frames with apertures of 130 cm 2. Problems related to the parting agent preparation, floating procedure, and mounting onto frames are discussed. Special precautions necessary to avoid damage during foil drying, storage and transportation are suggested.

Thin Foil Acceleration Method for Measuring the Unloading Isentropes of Shock-Compressed Matter

International Nuclear Information System (INIS)

Asay, J.R.; Chhabildas, L.C.; Fortov, V.E.; Kanel, G.I.; Khishchenko, K.V.; Lomonosov, I.V.; Mehlhorn, T.; Razorenov, S.V.; Utkin, A.V.

1999-01-01

This work has been performed as part of the search for possible ways to utilize the capabilities of laser and particle beams techniques in shock wave and equation of state physics. The peculiarity of these techniques is that we have to deal with micron-thick targets and not well reproducible incident shock wave parameters, so all measurements should be of a high resolution and be done in one shot. Besides the Hugoniots, the experimental basis for creating the equations of state includes isentropes corresponding to unloading of shock-compressed matter. Experimental isentrope data are most important in the region of vaporization. With guns or explosive facilities, the unloading isentrope is recovered from a series of experiments where the shock wave parameters in plates of standard low-impedance materials placed behind the sample are measured [1,2]. The specific internal energy and specific volume are calculated from the measured p(u) release curve which corresponds to the Riemann integral. This way is not quite suitable for experiments with beam techniques where the incident shock waves are not well reproducible. The thick foil method [3] provides a few experimental points on the isentrope in one shot. When a higher shock impedance foil is placed on the surface of the material studied, the release phase occurs by steps, whose durations correspond to that for the shock wave to go back and forth in the foil. The velocity during the different steps, connected with the knowledge of the Hugoniot of the foil, allows us to determine a few points on the isentropic unloading curve. However, the method becomes insensitive when the low pressure range of vaporization is reached in the course of the unloading. The isentrope in this region can be measured by recording the smooth acceleration of a thin witness plate foil. With the mass of the foil known, measurements of the foil acceleration will give us the vapor pressure

A Systems Approach to the Solid Lubrication of Foil Air Bearings for Oil-Free Turbomachinery

Science.gov (United States)

DellaCorte, Christopher; Zaldana, Antonio R.; Radil, Kevin C.

2002-01-01

Foil air bearings are self-acting hydrodynamic bearings which rely upon solid lubricants to reduce friction and minimize wear during sliding which occurs at start-up and shut-down when surface speeds are too low to allow the formation of a hydrodynamic air film. This solid lubrication is typically accomplished by coating the non-moving foil surface with a thin, soft polymeric film. The following paper introduces a systems approach in which the solid lubrication is provided by a combination of self lubricating shaft coatings coupled with various wear resistant and lubricating foil coatings. The use of multiple materials, each providing different functions is modeled after oil-lubricated hydrodynamic sleeve bearing technology which utilizes various coatings and surface treatments in conjunction with oil lubricants to achieve optimum performance. In this study, room temperature load capacity tests are performed on journal foil air bearings operating at 14,000 rpm. Different shaft and foil coating technologies such as plasma sprayed composites, ceramic, polymer and inorganic lubricant coatings are evaluated as foil bearing lubricants. The results indicate that bearing performance is improved through the individual use of the lubricants and treatments tested. Further, combining several solid lubricants together yielded synergistically better results than any material alone.

Stainless Steel Foil with Improved Creep-Resistance for Use in Primary Surface Recuperators for Gas Turbine Engines

International Nuclear Information System (INIS)

Browning, P.F.; Fitzpatrick, M.; Grubb, J.F.; Klug, R.C.; Maziasz, P.J.; Montague, J.P.; Painter, R.A.; Swindeman, R.W.

1998-01-01

Primary surface recuperators (PSRs) are compact heat-exchangers made from thin-foil type 347 austenitic stainless steel, which boost the efficiency of land-based gas turbine engines. Solar Turbines uses foil folded into a unique corrugated pattern to maximize the primary surface area for efficient heat transfer between hot exhaust gas on one side, and the compressor discharge air on the other side of the foil. Allegheny-Ludlum produces 0.003 - 0.0035 in. thick foil for a range of current turbine engines using PSRs that operate at up to 660 degrees C. Laboratory-scale processing modification experiments recently have demonstrated that dramatic improvements can be achieved in the creep resistance of such typical 347 stainless steel foils. The modified processing enables fine NbC carbide precipitates to develop during creep at 650-700 degrees C, which provides strength even with a fine grain size. Such improved creep-resistance is necessary for advanced turbine systems that will demand greater materials performance and reliability at higher operating conditions. The next challenges are to better understand the nature of the improved creep resistance in these 347 stainless steel foil, and to achieve similar improvements with scale-up to commercial foil production

Passive Collecting of Solar Radiation Energy using Transparent Thermal Insulators, Energetic Efficiency of Transparent Thermal Insulators

Directory of Open Access Journals (Sweden)

Smajo Sulejmanovic

2014-11-01

Full Text Available This paper explains passive collection of solar radiation energy using transparent thermal insulators. Transparent thermal insulators are transparent for sunlight, at the same time those are very good thermal insulators. Transparent thermal insulators can be placed instead of standard conventional thermal insulators and additionally transparent insulators can capture solar radiation, transform it into heat and save heat just as standard insulators. Using transparent insulators would lead to reduce in usage of fossil fuels and would help protection of an environment and reduce effects of global warming, etc.

Particle bombardment and the genetic enhancement of crops: myths and realities

NARCIS (Netherlands)

Altpeter, F.; Baisakh, N.; Beachy, R.; Bock, R.; Capell, T.; Christou, P.; Daniell, H.; Datta, K.; Datta, S.; Dix, P.J.; Fauquet, C.; Huang, N.; Kohli, A.; Mooibroek, H.; Nicholson, L.; Nguyen, T.T.; Nugent, G.; Raemakers, C.J.J.M.; Romano, A.; Somers, D.A.; Stoger, E.; Taylor, N.; Visser, R.G.F.

2005-01-01

DNA transfer by particle bombardment makes use of physical processes to achieve the transformation of crop plants. There is no dependence on bacteria, so the limitations inherent in organisms such as Agrobacterium tumefaciens do not apply. The absence of biological constraints, at least until DNA

Corrections in the gold foil activation method for determination of neutron beam density

DEFF Research Database (Denmark)

Als-Nielsen, Jens Aage

1967-01-01

A finite foil thickness and deviation in the cross section from the 1ν law imply corrections in the determination of neutron beam densities by means of foil activation. These corrections, which depend on the neutron velocity distribution, have been examined in general and are given in a specific...

Prism Foil from an LCD Monitor as a Tool for Teaching Introductory Optics

Science.gov (United States)

Planinsic, Gorazd; Gojkosek, Mihael

2011-01-01

Transparent prism foil is part of a backlight system in LCD monitors that are widely used today. This paper describes the optical properties of the prism foil and several pedagogical applications suitable for undergraduate introductory physics level. Examples include experiments that employ refraction, total internal reflection, diffraction and…

On the preparation of self-supporting zinc target foils of separated isotopes

International Nuclear Information System (INIS)

Sugai, Isao.

1975-01-01

This is the second report on the practical method of preparation of targets for nuclear experiments following the previous one (INS-TL-121 (in Japanese)). In this report, a method is described for the preparation of self-supporting zinc foils from ZnO. The thicknesses of target foils and their uniformity were measured with an α-ray thickness gauge. (auth.)

Ion bombardment induced surface topography modification of clean and contaminated single crystal Cu and Si

International Nuclear Information System (INIS)

Lewis, G.W.; Kiriakides, G.; Carter, G.; Nobes, M.J.

1982-01-01

Among the several factors which lead to depth resolution deterioration during sputter profiling, surface morphological modification resulting from local differences of sputtering rate can be important. This paper reports the results of direct scanning, electron microscopic studies obtained quasi-dynamically during increasing fluence ion bombardment of the evolution of etch pit structures on Si and Cu, and how such elaboration may be suppressed. It also reports on the elaboration of contaminant-induced cone generation for different ion species bombardment. The influence of such etch pit and cone generation on achievable depth resolution is assessed. (author)

First experience with carbon stripping foils for the 160 MeV H- injection into the CERN PSB

Science.gov (United States)

Weterings, Wim; Bracco, Chiara; Jorat, Louise; Noulibos, Remy; van Trappen, Pieter

2018-05-01

160 MeV H- beam will be delivered from the new CERN linear accelerator (Linac4) to the Proton Synchrotron Booster (PSB), using a H- charge-exchange injection system. A 200 µg/cm2 carbon stripping foil will convert H- into protons by stripping off the electrons. The H- charge-exchange injection principle will be used for the first time in the CERN accelerator complex and involves many challenges. In order to gain experience with the foil changing mechanism and the very fragile foils, in 2016, prior to the installation in the PSB, a stripping foil test stand has been installed in the Linac4 transfer line. In addition, parts of the future PSB injection equipment are also temporarily installed in the Linac4 transfer line for tests with a 160 MeV H- commissioning proton beam. This paper describes the foil changing mechanism and control system, summarizes the practical experience of gluing and handling these foils and reports on the first results with beam.

An Assessment of Gas Foil Bearing Scalability and the Potential Benefits to Civilian Turbofan Engines

Science.gov (United States)

Bruckner, Robert J.

2010-01-01

Over the past several years the term oil-free turbomachinery has been used to describe a rotor support system for high speed turbomachinery that does not require oil for lubrication, damping, or cooling. The foundation technology for oil-free turbomachinery is the compliant foil bearing. This technology can replace the conventional rolling element bearings found in current engines. Two major benefits are realized with this technology. The primary benefit is the elimination of the oil lubrication system, accessory gearbox, tower shaft, and one turbine frame. These components account for 8 to 13 percent of the turbofan engine weight. The second benefit that compliant foil bearings offer to turbofan engines is the capability to operate at higher rotational speeds and shaft diameters. While traditional rolling element bearings have diminished life, reliability, and load capacity with increasing speeds, the foil bearing has a load capacity proportional to speed. The traditional applications for foil bearings have been in small, lightweight machines. However, recent advancements in the design and manufacturing of foil bearings have increased their potential size. An analysis, grounded in experimentally proven operation, is performed to assess the scalability of the modern foil bearing. This analysis was coupled to the requirements of civilian turbofan engines. The application of the foil bearing to larger, high bypass ratio engines nominally at the 120 kN (approx.25000 lb) thrust class has been examined. The application of this advanced technology to this system was found to reduce mission fuel burn by 3.05 percent.

The Fabrication Technology Development of Uniform U and U-Mo Foil by Twin Roll Casting

International Nuclear Information System (INIS)

Kim, C. K.; Kim, K. H.; Lee, Y. S.; Woo, Y. M.; Kim, J. D.; Oh, J. M.; Sim, M. S.

2012-01-01

Uranium foil samples, of which the technology was developed by KAERI around 2000, were distributed to 6 countries including USA in connection with CRP of IAEA. A problem of thickness irregularity was issued so that cold work was done on it. Due to the pin hole and preferred orientation occurrence an additional development project was raised. It was presumed that the irregularity would be influenced by the eddy flow of the melt. So the melt feeding system was changed from pressurized melt flow to gravity-forced flow for more stable melt flow. And then It was tried that the bulgies on the foil surface were eliminated by deforming with a pressing roll. To save the production cost the expensive quartz crucible was replaced with a common graphite plugging crucible system with repeatable use. The loss of very expensive LEU material from melt leak of open nozzle in quartz crucible could be excluded. A new foil collection winding system was adopted so that the quickly coming-out foil could be taken without rumpling. The equipment was test-run with Cu as surrogate. Some drawbacks found during test-running were solved by modifying several parts. Cu foils could be produced with optimized conditions successfully. DU metal was also used for test-running the modified equipment and then some related modifications were done. Finally DU foils meeting the requesting specification could be produced. The length was longer than 10 m. The foil thickness ranged from 140 μm to 300 μm. On observation and measurement the thickness homogeneity was evaluated to be improved a little

High resistivity in InP by helium bombardment

International Nuclear Information System (INIS)

Focht, M.W.; Macrander, A.T.; Schwartz, B.; Feldman, L.C.

1984-01-01

Helium implants over a fluence range from 10 11 to 10 16 ions/cm 2 , reproducibly form high resistivity regions in both p- and n-type InP. Average resistivities of greater than 10 9 Ω cm for p-type InP and of 10 3 Ω cm for n-type InP are reported. Results are presented of a Monte Carlo simulation of helium bombardment into the compound target InP that yields the mean projected range and the range straggling

Experimental and theoretical study on minimum achievable foil thickness during asymmetric rolling.

Directory of Open Access Journals (Sweden)

Delin Tang

Full Text Available Parts produced by microforming are becoming ever smaller. Similarly, the foils required in micro-machines are becoming ever thinner. The asymmetric rolling technique is capable of producing foils that are thinner than those produced by the conventional rolling technique. The difference between asymmetric rolling and conventional rolling is the 'cross-shear' zone. However, the influence of the cross-shear zone on the minimum achievable foil thickness during asymmetric rolling is still uncertain. In this paper, we report experiments designed to understand this critical influencing factor on the minimum achievable thickness in asymmetric rolling. Results showed that the minimum achievable thickness of rolled foils produced by asymmetric rolling with a rolling speed ratio of 1.3 can be reduced to about 30% of that possible by conventional rolling technique. Furthermore, the minimum achievable thickness during asymmetric rolling could be correlated to the cross-shear ratio, which, in turn, could be related to the rolling speed ratio. From the experimental results, a formula to calculate the minimum achievable thickness was established, considering the parameters cross-shear ratio, friction coefficient, work roll radius, etc. in asymmetric rolling.

Experimental and theoretical study on minimum achievable foil thickness during asymmetric rolling.

Science.gov (United States)

Tang, Delin; Liu, Xianghua; Song, Meng; Yu, Hailiang

2014-01-01

Parts produced by microforming are becoming ever smaller. Similarly, the foils required in micro-machines are becoming ever thinner. The asymmetric rolling technique is capable of producing foils that are thinner than those produced by the conventional rolling technique. The difference between asymmetric rolling and conventional rolling is the 'cross-shear' zone. However, the influence of the cross-shear zone on the minimum achievable foil thickness during asymmetric rolling is still uncertain. In this paper, we report experiments designed to understand this critical influencing factor on the minimum achievable thickness in asymmetric rolling. Results showed that the minimum achievable thickness of rolled foils produced by asymmetric rolling with a rolling speed ratio of 1.3 can be reduced to about 30% of that possible by conventional rolling technique. Furthermore, the minimum achievable thickness during asymmetric rolling could be correlated to the cross-shear ratio, which, in turn, could be related to the rolling speed ratio. From the experimental results, a formula to calculate the minimum achievable thickness was established, considering the parameters cross-shear ratio, friction coefficient, work roll radius, etc. in asymmetric rolling.

Flow over a traveling wavy foil with a passively flapping flat plate

Science.gov (United States)

Liu, Nansheng; Peng, Yan; Liang, Youwen; Lu, Xiyun

2012-05-01

Flow over a traveling wavy foil with a passively flapping flat plate has been investigated using a multiblock lattice Boltzmann equation and the immersed boundary method. The foil undergoes prescribed undulations in the lateral direction and the rigid flat plate has passive motion determined by the fluid structure interaction. This simplified model is used to study the effect of the fish caudal fin and its flexibility on the locomotion of swimming animals. The flexibility of the caudal fin is modeled by a torsion spring acting about the pivot at the conjuncture of the wavy foil and the flat plate. The study reveals that the passively oscillating flat plate contributes half of the propulsive force. The flexibility, represented by the nondimensional natural frequency F, plays a very important role in the movement and propulsive force generation of the whole body. When the plate is too flexible, the drag force is observed. As the flat plate becomes more rigid, the propulsive force that is generated when the undulation is confined to last part of the wavy foil becomes larger. The steady movement occurs at F=5. These results are consistent with the observations of some swimming animals in nature.

Electronic excitation in transmission of relativistic H- ions through thin foils

International Nuclear Information System (INIS)

Reinhold, C.O.; Kuerpick, P.; Burgdoerfer, J.; Yoshida, S.

1998-01-01

The authors describe a theoretical model to study the transmission of relativistic H - ions through thin carbon foils. The approach is based on a Monte Carlo solution of the Langevin equation describing electronic excitations of the atoms during the transport through the foil. Calculations for the subshell populations of outgoing hydrogen atoms are found to be in good agreement with recent experimental data on an absolute scale and show that there exists a propensity for populating extreme Stark states

Large-area thin self-supporting carbon foils with MgO coatings

CERN Document Server

Stolarz, A

2002-01-01

Large area self-supporting carbon foils in the thickness of range of 8-22 mu g/cm sup 2 , coated with approximately 4 mu g/cm sup 2 MgO have been prepared by e-gun evaporation. They were mounted on frames with apertures of 130 cm sup 2. Problems related to the parting agent preparation, floating procedure, and mounting onto frames are discussed. Special precautions necessary to avoid damage during foil drying, storage and transportation are suggested.

Large-area thin self-supporting carbon foils with MgO coatings

Energy Technology Data Exchange (ETDEWEB)

Stolarz, Anna E-mail: anna@slcj.uw.edu.pl; Maier-Komor, Peter

2002-03-11

Large area self-supporting carbon foils in the thickness of range of 8-22 {mu}g/cm{sup 2}, coated with approximately 4 {mu}g/cm{sup 2} MgO have been prepared by e-gun evaporation. They were mounted on frames with apertures of 130 cm{sup 2}. Problems related to the parting agent preparation, floating procedure, and mounting onto frames are discussed. Special precautions necessary to avoid damage during foil drying, storage and transportation are suggested.

Tandem accelerator transmission and life measurement of 50 keV/amu Au ions using stripper foil made by INS

Energy Technology Data Exchange (ETDEWEB)

Ishii, Satoshi; Takahashi, Tsutomu; Shima, Kunihiro [Tsukuba Univ., Ibaraki (Japan). Tandem Accelerator Center; Sugai, Isamu; Oyaizu, Mitsuhiro

1996-12-01

The role of stripper foil is the charge exchange of ions. The thickness for attaining equilibrium in charge exchange becomes thinner as ions become lower speed and heavier. Accordingly, for the stripper foil, thin foil thickness is demanded in addition to the demand of long life. The stripper foil made by INS, University of Tokyo, is recognized as its long life. In the 12 UD PELETRON tandem accelerator in University of Tsukuba, in order to meet the demand of users to use heavy ions, the use of long life stripper foil has become urgent necessity. Therefore, as for the foil made by INS, the life by Au ion irradiation and the Au ion transmission were measured four times. As to the features of the test of this time, irradiation was carried out under the severe condition for the foil of low speed Au ions, and the change of beam transmission with time lapse was observed in addition to the life. The method of measurement is explained. The preparation of foils and the determination of their thickness are reported. As the results, the lifetime of the foils made by INS and the thickness dependence and time dependence or dose dependence of the transmission of low speed, heavy Au-197 ions are described. (K.I.)

Target bombardment by ion beams generated in the Focus experiment

International Nuclear Information System (INIS)

Bernard, Alain; Coudeville, Alain; Garconnet, J.-P.; Jolas, A.; Mascureau, J. de; Nazet, Christian.

1976-01-01

In a Mather-Focus experiment, it was shown that 80% of the neutron emitted were generated through bombardment. The apparatus was operated with various targets at a distance of 13mm from the anode. In the low pressure regime, a deuteron beam of high energy was produced. Its emission duration was measured using a CD 2 target [fr

Surface structure deduced differences of copper foil and film for graphene CVD growth

Energy Technology Data Exchange (ETDEWEB)

Tian, Junjun [School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China); Hu, Baoshan, E-mail: hubaoshan@cqu.edu.cn [School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China); Wei, Zidong; Jin, Yan [School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China); Luo, Zhengtang [Department of Chemical and Biomolecular Engineering, The Hongkong University of Science and Technology, Kowloon (Hong Kong); Xia, Meirong [School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China); Pan, Qingjiang [Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, Heilongjiang University, Harbin 150080 (China); Liu, Yunling [State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012 (China)

2014-05-01

Highlights: • We demonstrate the significant differences between Cu foil and film in the surface morphology and crystal orientation distribution. • The different surface structure leads to the distinctive influences of the CH₄ and H₂ concentrations on the thickness and quality of as-grown graphene. • Nucleation densities and growth rate differences at the initial growth stages on the Cu foil and film were investigated and discussed. Abstract: Graphene was synthesized on Cu foil and film by atmospheric pressure chemical vapor deposition (CVD) with CH₄ as carbon source. Electron backscattered scattering diffraction (EBSD) characterization demonstrates that the Cu foil surface after the H₂-assisted pre-annealing was almost composed of Cu(1 0 0) crystal facet with larger grain size of ~100 μm; meanwhile, the Cu film surface involved a variety of crystal facets of Cu(1 1 1), Cu(1 0 0), and Cu(1 1 0), with the relatively small grain size of ~10 μm. The different surface structure led to the distinctive influences of the CH₄ and H₂ concentrations on the thickness and quality of as-grown graphene. Further data demonstrate that the Cu foil enabled more nucleation densities and faster growth rates at the initial growth stages than the Cu film. Our results are beneficial for understanding the relationship between the metal surface structure and graphene CVD growth.

Self-Healing Wire Insulation

Science.gov (United States)

Parrish, Clyde F. (Inventor)

2012-01-01

A self-healing system for an insulation material initiates a self-repair process by rupturing a plurality of microcapsules disposed on the insulation material. When the plurality of microcapsules are ruptured, reactants within the plurality of microcapsules react to form a replacement polymer in a break of the insulation material. This self-healing system has the ability to repair multiple breaks in a length of insulation material without exhausting the repair properties of the material.

Low energy Ar ion bombardment damage of Si, GaAs, and InP surfaces

International Nuclear Information System (INIS)

Williams, R.S.

1982-01-01

Argon bombardment damage to (100) surfaces of Si, GaAs, and InP for sputter ion-gun potentials of 1, 2, and 3 kilovolts was studied using Rutherford backscattering. Initial damage rates and saturation damage levels were determined. Bombardment damage sensitivity increased for the sequence Si, GaAs, and InP. Saturation damage levels for Si and GaAs correspond reasonably to LSS projected range plus standard deviation estimates; damage to InP exceeded this level significantly. For an ion-gun potential of 3 keV, the initial sputter yield of P from an InP surface exceeded the sputter yield of In by four atoms per incident Ar projectile. (author)

Method for fabrication of ceramic dielectric films on copper foils

Science.gov (United States)

Ma, Beihai; Narayanan, Manoj; Dorris, Stephen E.; Balachandran, Uthamalingam

2015-03-10

The present invention provides a method for fabricating a ceramic film on a copper foil. The method comprises applying a layer of a sol-gel composition onto a copper foil. The sol-gel composition comprises a precursor of a ceramic material suspended in 2-methoxyethanol. The layer of sol-gel is then dried at a temperature up to about 250.degree. C. The dried layer is then pyrolyzed at a temperature in the range of about 300 to about 450.degree. C. to form a ceramic film from the ceramic precursor. The ceramic film is then crystallized at a temperature in the range of about 600 to about 750.degree. C. The drying, pyrolyzing and crystallizing are performed under a flowing stream of an inert gas. In some embodiments an additional layer of the sol-gel composition is applied onto the ceramic film and the drying, pyrolyzing and crystallizing steps are repeated for the additional layer to build up a thicker ceramic layer on the copper foil. The process can be repeated one or more times if desired.

Actinide Foil Production for MPACT Research

Energy Technology Data Exchange (ETDEWEB)

Beller, Denis

2012-10-30

Sensitive fast-neutron detectors are required for use in lead slowing down spectrometry (LSDS), an active interrogation technique for used nuclear fuel assay for Materials Protection, Accounting, and Controls Technologies (MPACT). During the past several years UNLV sponsored a research project at RPI to investigate LSDS; began development of fission chamber detectors for use in LSDS experiments in collaboration with INL, LANL, and Oregon State U.; and participated in a LSDS experiment at LANL. In the LSDS technique, research has demonstrated that these fission chamber detectors must be sensitive to fission energy neutrons but insensitive to thermal-energy neutrons. Because most systems are highly sensitive to large thermal neutron populations due to the well-known large thermal cross section of 235U, even a miniscule amount of this isotope in a fission chamber will overwhelm the small population of higher-energy neutrons. Thus, fast-fission chamber detectors must be fabricated with highly depleted uranium (DU) or ultra-pure thorium (Th), which is about half as efficient as DU. Previous research conducted at RPI demonstrated that the required purity of DU for assay of used nuclear fuel using LSDS is less than 4 ppm 235U, material that until recently was not available in the U.S. In 2009 the PI purchased 3 grams of ultra-depleted uranium (uDU, 99.99998% 238U with just 0.2 ± 0.1 ppm 235U) from VNIIEF in Sarov, Russia. We received the material in the form of U3O8 powder in August of 2009, and verified its purity and depletion in a FY10 MPACT collaboration project. In addition, chemical processing for use in FC R&D was initiated, fission chamber detectors and a scanning alpha-particle spectrometer were developed, and foils were used in a preliminary LSDS experiment at a LANL/LANSCE in Sept. of 2010. The as-received U3O8 powder must be chemically processed to convert it to another chemical form while maintaining its purity, which then must be used to electro-deposit U

The development of cones and associated features on ion bombarded copper

International Nuclear Information System (INIS)

Whitton, J.L.; Carter, G.; Nobes, M.J.; Williams, J.S.

1977-01-01

Observations of ion-bombardment-induced surface modifications on crystalline copper substrates have been made using scanning electron microscopy. The delineation and development of grain boundary edges, faceted and terraced etch pits and small-scale ripple structure, together with the formation of faceted conical features, have all been observed on low and high purity polycrystalline substrates. In general, the density of such surface morphological features, although variable from grain to grain, is higher in the proximity of grain boundaries. In particular, cones are only found within regions where other surface erosional features are present and it would appear that the development of these other features is a pre-requisite to cone generation in high-purity crystalline substrates. We suggest the operation of a defect-induced mechanism of cone formation whereby sputter elaboration of bulk defects (either pre-existing or bombardment-induced) leads to the formation and development of surface features which, in turn, may intersect and result in the generation of cones. (author)

The development of cones and associated features on ion bombarded copper

International Nuclear Information System (INIS)

Whitton, J.L.; Williams, J.S.

1977-01-01

Observations of ion-bombardment-induced surface modifications on crystalline copper substrates have been made using scanning electron microscopy. The delineation and development of grain boundary edges, faceted and terraced etch pits and small-scale ripple structure, together with the formation of faceted conical features have all been observed on low and high purity polycrystalline substrates. In general, the density of such surface morphological features, although variable from grain to grain, is higher in the proximity of grain boundaries. In particular, cones are only found within regions where other surface erosional features are present and it would appear that the development of these other surface features is a pre-requisite to cone generation in high-purity crystalline substrates. The authors suggest the operation of a defect-induced mechanism of cone formation whereby sputter elaboration of bulk defects (either preexisting or bombardment-induced) leads to the formation and development of surface features which, in turn, may intersect and result in the generation of cones. (Auth.)

Influence of ion bombardment induced patterning of exchange bias in pinned artificial ferrimagnets on the interlayer exchange coupling

Energy Technology Data Exchange (ETDEWEB)

Schmalhorst, Jan; Reiss, Guenter; Hoenik, V. [Thin Films and Nanostructures, Department of Physics, Univ. Bielefeld (Germany); Weis, Tanja; Engel, Dieter; Ehresmann, Arno [Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology, Kassel Univ. (Germany)

2007-07-01

Artificial ferrimagnets (AFi) have many applications as, e.g., pinned reference electrodes in magnetic tunnel junctions. It is known that the application of ion bombardment induced magnetic patterning with He ions on a single layer reference electrode of magnetic tunnel junctions is possible. For some applications a combination of ion bombardment induced magnetic patterning and artificial ferrimagnets as a reference electrode is desirable. The effect of ion bombardment induced magnetic patterning on pinned artificial ferrimagnets with a Ru interlayer which is frequently used in magnetic tunnel junctions as well as pinned AFis with a Cu interlayer has been tested. Special attention has been given to the question whether the antiferromagnetic interlayer exchange coupling can withstand the ion dose necessary to turn the exchange bias.

Flexible AMOLED display on polyethylene napthalate (PEN) foil with metal-oxide TFT backplane

NARCIS (Netherlands)

Tripathi, A.K.; Putten, B. van der; Steen, J.L. van der; Tempelaars, K.; Cobb, B.; Ameys, M.; Ke, T.H.; Myny, K.; Steudel, S.; Nag, M.; Schols, S.; Vicca, P.; Smout, S.; Genoe, J.; Heremans, P.; Yakimets, I.; Gelinck, G.H.

2012-01-01

We present a top emitting monochrome AMOLED display with 85dpi resolution using an amorphous Indium-Gallium-Zinc-Oxide (IGZO) TFT backplane on PEN-foil. Maximum processing temperature was limited to 150 °C in order to ensure an overlay accuracy < 3μm on PEN foil. The backplane process flow is based

Optimizing dc-resistance of a foil wounded toroidal inductor combining matlab and comsol

DEFF Research Database (Denmark)

Schneider, Henrik; Andersen, Thomas; Knott, Arnold

2013-01-01

An optimization routine is presented to optimize the shape of a foil winding of a toroid inductor in terms of the DC resistance. MATLAB was used to define the geometry of the foil winding and COMSOL was used to import the geometry and create a 3D finite element model. The initial parameters...

Excitation functions and isomeric ratios for the isomeric pair sup(106m)Ag and sup(106g)Ag in the 107Ag (d,t) reaction

International Nuclear Information System (INIS)

Lalli, M.E.; Wasilevsky de Lammirato, C.; Herreros, O.R.; Nassiff, S.J.

1976-09-01

Excitation functions and isomeric cross section ratios have been measured for the 107 Ag (d,t), reaction in which the isomeric pair sup(106m/106g)Ag is produced. Thick-target yields have been determined for different irradiation times and as a function of deuteron energy. Stacked silver foils with aluminium foils as monitors were bombarded with deuterons up to 27 MeV and the activities of products measured with a calibrated Ge(Li) counter. (author) [es

X-ray emission, ablation pressure, and preheating for foils irradiated at 0. 26. mu. m wavelength

Energy Technology Data Exchange (ETDEWEB)

Pepin, H.; Fabbro, R.; Faral, B.; Amiranoff, F.; Virmont, J.; Cottet, F.; Romain, J.P.

1985-11-01

The x-ray emission, ablation pressure, and preheating for foils irradiated with a 0.26 ..mu..m laser at intensities approx.10/sup 15/ W cm/sup -2/ are studied. The foils are Al with various thicknesses, coated or uncoated with CH or Au. The x-ray emission and conversion efficiency are obtained with a multichannel x-ray diode spectrometer, the ablation pressures are deduced from shock transit times, and the rear temperatures are inferred from x-ray pyrometry. For thin foils (<<12 ..mu..m), the rear temperatures can be predicted reasonably well with the use of the front x-ray spectra. For thick foils shock preheating is dominant.

X-ray emission, ablation pressure, and preheating for foils irradiated at 0.26 μm wavelength

International Nuclear Information System (INIS)

Pepin, H.; Fabbro, R.; Faral, B.; Amiranoff, F.; Virmont, J.; Cottet, F.; Romain, J.P.

1985-01-01

The x-ray emission, ablation pressure, and preheating for foils irradiated with a 0.26 μm laser at intensities approx.10 15 W cm -2 are studied. The foils are Al with various thicknesses, coated or uncoated with CH or Au. The x-ray emission and conversion efficiency are obtained with a multichannel x-ray diode spectrometer, the ablation pressures are deduced from shock transit times, and the rear temperatures are inferred from x-ray pyrometry. For thin foils (<<12 μm), the rear temperatures can be predicted reasonably well with the use of the front x-ray spectra. For thick foils shock preheating is dominant

High-resolution x-ray imaging of planar foils irradiated by the Nike KrF laser

International Nuclear Information System (INIS)

Brown, C.; Seely, J.; Feldman, U.; Obenschain, S.; Bodner, S.; Pawley, C.; Gerber, K.; Sethian, J.; Mostovych, A.; Aglitskiy, Y.; Lehecka, T.; Holland, G.

1997-01-01

Thin plastic (CH) foils were irradiated by the Naval Research Laboratory Nike [Obenschain et al., Phys. Plasmas 3, 2098 (1996)] KrF laser and were imaged in the x-ray and extreme ultraviolet regions with two-dimensional spatial resolution in the 3 endash 10 μm range. The CH foils were backlit by a silicon plasma. A spherically curved quartz crystal produced monochromatic images of the Si +12 resonance line radiation with energy 1865 eV that was transmitted by the CH foils. Instabilities that were seeded by linear ripple patterns on the irradiated sides of CH foils were observed. The ripple patterns had periods in the 31 endash 125 μm range and amplitudes in the 0.25 endash 5.0 μm range. The silicon backlighter emission was recorded by an x-ray spectrometer, and the 1865 eV resonance line emission was recorded by a fast x-ray diode. The multilayer mirror telescope recorded images of the C +3 1550 Angstrom emission (energy 8.0 eV) from the backside of the CH foils. copyright 1997 American Institute of Physics

Ion bombardment induced smoothing of amorphous metallic surfaces: Experiments versus computer simulations

International Nuclear Information System (INIS)

Vauth, Sebastian; Mayr, S. G.

2008-01-01

Smoothing of rough amorphous metallic surfaces by bombardment with heavy ions in the low keV regime is investigated by a combined experimental-simulational study. Vapor deposited rough amorphous Zr 65 Al 7.5 Cu 27.5 films are the basis for systematic in situ scanning tunneling microscopy measurements on the smoothing reaction due to 3 keV Kr + ion bombardment. The experimental results are directly compared to the predictions of a multiscale simulation approach, which incorporates stochastic rate equations of the Langevin type in combination with previously reported classical molecular dynamics simulations [Phys. Rev. B 75, 224107 (2007)] to model surface smoothing across length and time scales. The combined approach of experiments and simulations clearly corroborates a key role of ion induced viscous flow and ballistic effects in low keV heavy ion induced smoothing of amorphous metallic surfaces at ambient temperatures

Composition and structure of ion-bombardment-induced growth cones on InP

International Nuclear Information System (INIS)

Malherbe, J.B.; Lakner, H.; Gries, W.H.

1991-01-01

The previously reported effect of low-energy (several keV) ion bombardment on the surface topography of InP was investigated by scanning transmission electron microscopy. Convergent beam electron diffraction patterns of the surface growth 'cones' induced by argon ion bombardment of (100) InP between 7 and 10 keV proved the cones to consist of crystalline InP (and not metallic indium, as has sometimes been claimed). The investigation showed that the irradiated surface region is not rendered completely amorphous but that it recrystallizes from the crystalline/amorphous interface in a columnar growth pattern, often terminating in growth cones protruding above the surface. Weak beam investigations revealed that the overwhelming majority of the cones have the orientation of the substrate. These phenomena were observed at all dose densities from 7 x 10 15 to 2 x 10 17 cm -2 . (author)

Effect of phototherapy with alumunium foil reflectors on neonatal hyperbilirubinemia

Directory of Open Access Journals (Sweden)

Tony Ijong Dachlan

2015-03-01

Full Text Available Background Neonatal hyperbilirubinemia (NH is one of the most common problems in neonates, but it can be treated with blue light phototherapy. Developing countries with limited medical equipment and funds have difficulty providing effective phototherapy to treat NH, leading to increased risk of bilirubin encephalopathy. Phototherapy with white reflecting curtains can decrease the duration of phototherapy needed to reduce bilirubin levels. Objective To compare the duration of phototherapy needed in neonates with NH who underwent phototherapy with and without aluminum foil reflectors. Methods This open clinical trial was conducted from July to August 2013 at Dr. Hasan Sadikin Hospital, Bandung, Indonesia. The inclusion criteria were term neonates with uncomplicated NH presenting in their first week of life. Subjects were randomized into two groups, those who received phototherapy with or without aluminum foil reflectors. Serum bilirubin is taken at 12th, 24th, 48th hours, then every 24 hours if needed until phototherapy can be stopped according to American Academy of Pediatrics guidelines. The outcome measured was the duration of phototherapy using survival analysis. The difference between the two groups was tested by Gehan method. Results Seventy newborns who fulfilled the inclusion criteria and had similar characteristics were randomized into two groups. The duration of phototherapy needed was significantly less in the group with aluminum foil reflectors than in the group without reflectors [72 vs. 96 hours, respectively, (P<0.01]. Conclusion The required duration of phototherapy with aluminum foil reflectors is significantly less than that of phototherapy without reflectors, in neonates with NH.

Convergent beam thickness determination of thin foil zirconium specimens

International Nuclear Information System (INIS)

Cann, C.D.

1978-07-01

The use of convergent beam patterns to determine the thickness of zirconium foils observed in the electron microscope has been investigated both theoretically and experimentally. On the basis of many-beam dynamical theory calculations, the [1012], [1013], and [1120] reflections at an accelerating voltage of 100 kV and the [1013], [1120], and [1122] reflections at 200 kV were found most suitable for convergent beam thickness determinations. Experimental convergent beam patterns were obtained in the JEOL-200B electron microscope under two different sets of conditions based on the size of the pattern desired. Computer assisted analysis of the patterns obtained gave foil thicknesses in good agreement with those determined from thickness extinction contours. (author)

Radon-thoron discrimination using a polythene foil: an application in uranium exploration

International Nuclear Information System (INIS)

Ramola, R.C.; Singh, M.; Sandhu, A.S.; Singh, S.; Virk, H.S.

1989-01-01

Integrated measurements of radon concentrations in subsurface soil are being used extensively for uranium exploration and earthquake prediction. For uranium exploration only the radon signals are needed; however, a part of the α-activity may derive from thoron. To exclude thoron, a polythene foil has been used as an anti-thoron membrane to delay the entry of thoron into the detector system so that only the longer lived isotope 222 Rn survives to be measured. A long term integrated measurement has been carried out using LR-115 and CR-39 plastic track detectors. The observed track density has been determined as a function of foil thickness. It is found that a polythene foil of appropriate thickness could be successfully employed for the separation of radon and thoron in soil. (author)

Thin silicon foils produced by epoxy-induced spalling of silicon for high efficiency solar cells

Energy Technology Data Exchange (ETDEWEB)

Martini, R., E-mail: roberto.martini@imec.be [Department of Electrical Engineering, KU Leuven, Kasteelpark 10, 3001 Leuven (Belgium); imec, Kapeldreef 75, 3001 Leuven (Belgium); Kepa, J.; Stesmans, A. [Department of Physics, KU Leuven, Celestijnenlaan 200 D, 3001 Leuven (Belgium); Debucquoy, M.; Depauw, V.; Gonzalez, M.; Gordon, I. [imec, Kapeldreef 75, 3001 Leuven (Belgium); Poortmans, J. [Department of Electrical Engineering, KU Leuven, Kasteelpark 10, 3001 Leuven (Belgium); imec, Kapeldreef 75, 3001 Leuven (Belgium); Universiteit Hasselt, Martelarenlaan 42, B-3500 Hasselt (Belgium)

2014-10-27

We report on the drastic improvement of the quality of thin silicon foils produced by epoxy-induced spalling. In the past, researchers have proposed to fabricate silicon foils by spalling silicon substrates with different stress-inducing materials to manufacture thin silicon solar cells. However, the reported values of effective minority carrier lifetime of the fabricated foils remained always limited to ∼100 μs or below. In this work, we investigate epoxy-induced exfoliated foils by electron spin resonance to analyze the limiting factors of the minority carrier lifetime. These measurements highlight the presence of disordered dangling bonds and dislocation-like defects generated by the exfoliation process. A solution to remove these defects compatible with the process flow to fabricate solar cells is proposed. After etching off less than 1 μm of material, the lifetime of the foil increases by more than a factor of 4.5, reaching a value of 461 μs. This corresponds to a lower limit of the diffusion length of more than 7 times the foil thickness. Regions with different lifetime correlate well with the roughness of the crack surface which suggests that the lifetime is now limited by the quality of the passivation of rough surfaces. The reported values of the minority carrier lifetime show a potential for high efficiency (>22%) thin silicon solar cells.

Thin silicon foils produced by epoxy-induced spalling of silicon for high efficiency solar cells

International Nuclear Information System (INIS)

Martini, R.; Kepa, J.; Stesmans, A.; Debucquoy, M.; Depauw, V.; Gonzalez, M.; Gordon, I.; Poortmans, J.

2014-01-01

We report on the drastic improvement of the quality of thin silicon foils produced by epoxy-induced spalling. In the past, researchers have proposed to fabricate silicon foils by spalling silicon substrates with different stress-inducing materials to manufacture thin silicon solar cells. However, the reported values of effective minority carrier lifetime of the fabricated foils remained always limited to ∼100 μs or below. In this work, we investigate epoxy-induced exfoliated foils by electron spin resonance to analyze the limiting factors of the minority carrier lifetime. These measurements highlight the presence of disordered dangling bonds and dislocation-like defects generated by the exfoliation process. A solution to remove these defects compatible with the process flow to fabricate solar cells is proposed. After etching off less than 1 μm of material, the lifetime of the foil increases by more than a factor of 4.5, reaching a value of 461 μs. This corresponds to a lower limit of the diffusion length of more than 7 times the foil thickness. Regions with different lifetime correlate well with the roughness of the crack surface which suggests that the lifetime is now limited by the quality of the passivation of rough surfaces. The reported values of the minority carrier lifetime show a potential for high efficiency (>22%) thin silicon solar cells.

An Effort to Improve U Foil Fabrication Technology of Roll-casting for Fission Mo Target

Energy Technology Data Exchange (ETDEWEB)

Kim, Chang Kyu; Woo, Yun Myeong; Kim, Ki Hwan; Oh, Jong Myeong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Sim, Moon Soo [Chungnam University, Green Energy Technology, Daejeon (Korea, Republic of)

2010-10-15

Mo-99 isotope has been produced mainly by extracting fission products of {sup 235}U. The targets for irradiating in reactor have used as stainless tube coated with highly enriched UO{sub 2} at the inside surface and highly enriched UAlx plate cladded with aluminum. In connection with non-proliferation policy the RERTR program developed a new process of Mo-99 using low enriched uranium (LEU) instead of highly enriched uranium (HEU). LEU should be put about five times more quantity than HEU because the {sup 235}U contents of LEU and HEU are 20% and higher than 90%, respectively. Accordingly pure uranium metal foil target was adopted as a promising target material due to high uranium density. ANL and BATAN developed a Cintichem process using uranium metal foil target of 130 {mu}m in thickness jointly and the RERTR program is trying to disseminate the new process world-widely. However, uranium foil is made by lots of times rolling work on uranium plate, which is laborious and tedious. In order to avoid this difficulty KAERI developed a new process of making foil directly from uranium melt by roll casting. This process is very much simple, productive, and cost-effective. But the outside surface of foil is generally very rough. A typical transverse cross section had a minimum thickness of 65 {mu}m and a maximum thickness of 205 {mu}m. This roughness could affect (1) target fabrication, where the U foil, or the Ni foil might be damaged during drawing, and (2) irradiation behavior, where gaps between the target walls and the U metal might affect cooling of the target

Optical temperature sensing on flexible polymer foils

Science.gov (United States)

Sherman, Stanislav; Xiao, Yanfen; Hofmann, Meike; Schmidt, Thomas; Gleissner, Uwe; Zappe, Hans

2016-04-01

In contrast to established semiconductor waveguide-based or glass fiber-based integrated optical sensors, polymerbased optical systems offer tunable material properties, such as refractive index or viscosity, and thus provide additional degrees of freedom for sensor design and fabrication. Of particular interest in sensing applications are fully-integrated optical waveguide-based temperature sensors. These typically rely on Bragg gratings which induce a periodic refractive index variation in the waveguide so that a resonant wavelength of the structure is reflected.1,2 With broad-band excitation, a dip in the spectral output of the waveguide is thus generated at a precisely-defined wavelength. This resonant wavelength depends on the refractive index of the waveguide and the grating period, yet both of these quantities are temperature dependent by means of the thermo-optic effect (change in refractive index with temperature) and thermal expansion (change of the grating period with temperature). We show the design and fabrication of polymer waveguide-integrated temperature sensors based on Bragggratings, fabricated by replication technology on flexible PMMA foil substrates. The 175 μm thick foil serves as lower cladding for a polymeric waveguide fabricated from a custom-made UV-crosslinkable co-monomer composition. The fabrication of the grating structure includes a second replication step into a separate PMMA-foil. The dimensions of the Bragg-gratings are determined by simulations to set the bias point into the near infrared wavelength range, which allows Si-based detectors to be used. We present design considerations and performance data for the developed structures. The resulting sensor's signal is linear to temperature changes and shows a sensitivity of -306 nm/K, allowing high resolution temperature measurements.

Electrochemically replicated smooth aluminum foils for anodic alumina nanochannel arrays

International Nuclear Information System (INIS)

Biring, Sajal; Tsai, K-T; Sur, Ujjal Kumar; Wang, Y-L

2008-01-01

A fast electrochemical replication technique has been developed to fabricate large-scale ultra-smooth aluminum foils by exploiting readily available large-scale smooth silicon wafers as the masters. Since the adhesion of aluminum on silicon depends on the time of surface pretreatment in water, it is possible to either detach the replicated aluminum from the silicon master without damaging the replicated aluminum and master or integrate the aluminum film to the silicon substrate. Replicated ultra-smooth aluminum foils are used for the growth of both self-organized and lithographically guided long-range ordered arrays of anodic alumina nanochannels without any polishing pretreatment

Electroplating of Uranium -Foil Target With Ni And Zn

International Nuclear Information System (INIS)

Husna AI Hasa, Muhammad; Suripto, Asmedi

2001-01-01

The uranium foil target, which was produced by rolling, was subjected to preparation treatment prior to the electroplating. The electroplating produced certain plate thickness on the foil surface. The electroplating was applied to the uranium foil of 71 mm long and 46 mm wide using plating materials of Ni and Zn. The plating is intended to serve as barrier for fission fragment recoils, which are produced during irradiation. The plate thickness produced by the electroplating was measured by a micrometer and an analytical balance. The electroplating with Ni produced plate-thickness of 8,9 mm when measured by the micrometer, or 11.4 mm when measured by the analytical balance, while the Zn electroplating produced greater plate-thickness, i.e. 16.2 mm by the micrometer measurement or 13.7 mm by the analytical balance measurement. The current efficiency of the electroplating was 62 % for Ni and 80 % for Zn. It was observed that the optimum condition for the electroplating depended on the plating materials, plating time, and current density. The plate-thickness produced under the optimum condition was 7-15 mm at 15 mA/cm 2 for Ni and ]0 mA/cm 2 for Zn with plating time of 60 minutes

Resonance effects of transition radiation emitted from thin foil stacks using electron beam

Energy Technology Data Exchange (ETDEWEB)

Awata, Takaaki; Yajima, Kazuaki; Tanaka, Takashi [Kyoto Univ. (Japan). Faculty of Engineering; and others