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Sample records for absorber-materials atomic numbers

  1. Simulated mixed absorbers and effective atomic numbers for γ ...

    Indian Academy of Sciences (India)

    The total -ray interaction crosss-sections on mixed absorbers were determined at 662 keV with a view to study the effective atomic numbers for -ray absorption under narrow beam good geometry set-up. The measurements were taken for the combination of metallic absorbers like aluminium, copper, lead and mercury ...

  2. Effective atomic numbers and electron density of dosimetric material

    Directory of Open Access Journals (Sweden)

    Kaginelli S

    2009-01-01

    Full Text Available A novel method for determination of mass attenuation coefficient of x-rays employing NaI (Tl detector system and radioactive sources is described.in this paper. A rigid geometry arrangement and gating of the spectrometer at FWHM position and selection of absorber foils are all done following detailed investigation, to minimize the effect of small angle scattering and multiple scattering on the mass attenuation coefficient, m/r, value. Firstly, for standardization purposes the mass attenuation coefficients of elemental foils such as Aluminum, Copper, Molybdenum, Tantalum and Lead are measured and then, this method is utilized for dosimetric interested material (sulfates. The experimental mass attenuation coefficient values are compared with the theoretical values to find good agreement between the theory and experiment within one to two per cent. The effective atomic numbers of the biological substitute material are calculated by sum rule and from the graph. The electron density of dosimetric material is calculated using the effective atomic number. The study has discussed in detail the attenuation coefficient, effective atomic number and electron density of dosimetric material/biological substitutes.

  3. Simulated mixed absorbers and effective atomic numbers for γ ...

    Indian Academy of Sciences (India)

    Keywords. γ-rays; γ attenuation; simulated mixed absorbers; effective atomic ... We have tried to simulate composite (mixed) absorbers ... Experimental method .... puter, Program manual, Centre for Radiation Research, National Bureau of ...

  4. Measurement of effective atomic number of composite materials using scattering of γ-rays

    International Nuclear Information System (INIS)

    Singh, M.P.; Sandhu, B.S.; Singh, Bhajan

    2007-01-01

    In the present experiment, to determine the effective atomic number of composite materials, the scattering of 145 keV γ-rays is studied using a high-resolution HPGe semiconductor detector placed at 70 deg. to the incident beam. The experiment is performed on various elements of different atomic number, 6≤Z≤64, for 145 keV incident photons. The intensity ratio of Rayleigh to Compton scattered peaks, corrected for photo-peak efficiency of the γ-detector and absorption of photons in the target and air, is plotted as a function of atomic number and constituted a fit curve. From this fit curve, the respective effective atomic numbers of the composite materials are determined. The agreement of measured values of effective atomic number with the theory is found to be quite satisfactory

  5. Conversion of ionization measurements to radiation absorbed dose in non-water density material

    International Nuclear Information System (INIS)

    El-Khatib, E.; Connors, S.

    1992-01-01

    In bone-equivalent materials two different calculations of absorbed dose are possible: the absorbed dose to soft tissue plastic (polystyrene) within bone-equivalent material and the dose to the bone-equivalent material itself. Both can be calculated from ionization measurements in phantoms. These two calculations result in significantly different doses in a heterogeneous phantom composed of polystyrene and aluminium (a bone substitute). The dose to a thin slab of polystyrene in aluminium is much higher than the dose to the aluminium itself at the same depth in the aluminium. Monte Carlo calculations confirm that the calculation of dose to polystyrene in aluminium can be accurately carried out using existing dosimetry protocols. However, the conversion of ionization measurements to absorbed dose to high atomic number materials cannot be accurately carried out with existing protocols and appropriate conversion factors need to be determined. (author)

  6. Determination of Atomic Number Exponent for Elemental Absorber at Am-241 Energy in X-Ray Attenuation Experiments

    International Nuclear Information System (INIS)

    Najim, L.A.; Shamoon, S.K.; Atalah, S.T.

    2012-01-01

    In X-ray absorption experiment, the dependence of the photoelectric absorption cross-section varied with atomic number Z.In this paper, the dependence on Z of the cross-section or coefficient of photoelectric absorption is first evaluated from published data for (20) elements ranging from Al-Sn, and then the cross-section for Fe is obtained experimentally by measuring the X-ray intensity with and without the Fe absorber and compared with the theoretical value, the variation of the photoelectric absorption coefficient (μ/ρ m ) showed less dependence on Z for the two tested of Z regions.This is because of the inclusion of mass density (ρ m ) of the absorber in the coefficient.The values of m obtained in the present work increases linearly with energy for both ranges of elements

  7. A method to determine exactly the effective atomic number, electron density and absorbtion coefficient of materials from two Computer-Tomography measurement

    International Nuclear Information System (INIS)

    Christ, G.

    1981-01-01

    By the method of computer tomography, which is in use since about 10 years, X-ray images of a layer of interest can be produced without interference from the material present above this layer. An integral measurement of the attenuation of continuous X-radiation is sufficient to record the different attenuation behaviour in a layer for the purpose of image formation. For more information, however, can be obtained by taking into account the spectral distribution of the X-ray source and the energy dependence of the attenuation, which varies for different materials. In the experimental part of this work the measurement of the spectral distribution is described together with the necessary corrections, and the possible application of the cross sections for the relevant interaction processes, which are known from the literature is studied. As shown in the theoretical part, the attenuation coefficient can be described by an effective atomic number and the electron density of the absorber in the case of an arbitrary mixture of absorbing materials and a continuous X-ray spectrum. These two unknown material parameters can be determined by a method based on the measurement of two spectra with different spectral distribution. This is demonstrated by a one-dimensional and a two-dimensional computer simulation. (orig./WU) [de

  8. Absorbant materials

    International Nuclear Information System (INIS)

    Quetier, Monique.

    1978-11-01

    Absorbants play a very important part in the nuclear industry. They serve for the control, shut-down and neutron shielding of reactors and increase the capacity of spent fuel storage pools and of special transport containers. This paper surveys the usual absorbant materials, means of obtainment, their essential characteristics relating to their use and their behaviour under neutron irradiation [fr

  9. Atomization in graphite-furnace atomic absorption spectrometry. Peak-height method vs. integration method of measuring absorbance: carbon rod atomizer 63

    International Nuclear Information System (INIS)

    Sturgeon, R.E.; Chakrabarti, C.L.; Maines, I.S.; Bertels, P.C.

    1975-01-01

    Oscilloscopic traces of transient atomic absorption signals generated during continuous heating of a Carbon Rod Atomizer model 63 show features which are characteristic of the element being atomized. This research was undertaken to determine the significance and usefulness of the two analytically significant parameters, absorbance maximum and integrated absorbance. For measuring integrated absorbance, an electronic integrating control unit consisting of a timing circuit, a lock-in amplifier, and a digital voltmeter, which functions as a direct absorbance x second readout, has been designed, developed, and successfully tested. Oscilloscopic and recorder traces of the absorbance maximum and digital display of the integrated absorbance are simultaneously obtained. For the elements studied, Cd, Zn, Cu, Al, Sn, Mo, and V, the detection limits and the precision obtained are practically identical for both methods of measurements. The sensitivities by the integration method are about the same as, or less than, those obtained by the peak-height method, whereas the calibration curves by the former are generally linear over wider ranges of concentrations. (U.S.)

  10. Absorbent material for type a radioactive materials packaging containing liquids

    International Nuclear Information System (INIS)

    Saunders, G.A.

    1989-11-01

    The application of absorbent materials to the packaging and transport of liquid radioactive materials in Type A packages has not been reported in the literature. However, a significant body of research exists on absorbent materials for personal hygiene products such as diapers. Absorption capacity is dependent on both the absorbent material and the liquid being absorbed. Theoretical principles for capillary absorption in both the horizontal and the vertical plane indicate that small contact angle between the absorbent fibre and the liquid, and a small inter-fibre pore size are important. Some fluid parameters such as viscosity affect the rate of absorption but not the final absorption capacity. There appears to be little comparability between results obtained for the same absorbent and fluid using different test procedures. Test samples of materials from several classes of potential absorbents have been evaluated in this study, and shown to have a wide range of absorbent capacities. Foams, natural fibres, artificial fibres and granular materials are all potentially useful absorbents, with capacities ranging from as little as 0.86 to as much as 40.6 grams of distilled water per gram of absorbent. Two experimental procedures for evaluating the absorbent capacity of these materials have been detailed in this report, and found suitable for evaluating granular, fibrous or foam materials. Compression of the absorbent material reduces its capacity, but parameters such as relative humidity, pH, temperature, and viscosity appear to have little significant influence on capacity. When the materials were loaded to 50% of their one-minute absorbency, subsequent loss of the absorbed liquid was generally minimal. All of the absorbent materials rapidly lost their absorbed water through evaporation within twenty-four hours in still air at 21 degrees C and 50% relative humidity

  11. Measurement of absorbed doses near metal and dental material interfaces irradiated by x- and gamma-ray therapy beams

    International Nuclear Information System (INIS)

    Farahani, M.; Eichmiller, F.C.; McLaughlin, W.L.

    1990-01-01

    Soft-tissue damage adjacent to dental restorations is a deleterious side effect of radiation therapy associated with low-energy electron scatter from dental materials of high electron density. This study was designed to investigate the enhancement of dose to soft tissue (or water) close to high electron-density materials and to measure the detailed lateral and depth-dose profiles in soft-tissue-simulating polymer adjacent to planar interfaces of several higher atomic-number materials: 18-carat gold dental casting alloy; Ag-Hg dental amalgam alloy; Ni-Cr dental casting alloy; and natural human tooth structure. Results indicate that the dose-enhancement in 'tissue' is as great as a factor of 2 on the backscatter side adjacent to gold and a factor of 1.2 adjacent to tooth tissue, but is insignificant on the forward-scatter side because of the predominant effect of attenuation by the high-density, high atomic-number absorbing material. (author)

  12. System and process for determining the basis weight of a low atomic number material in a mixture with a higher atomic number material

    International Nuclear Information System (INIS)

    Hegland, P.; Dahlquist, J.

    1985-01-01

    A process for determining the relative quantity of low atomic energy material mixed with a higher atomic energy material is carried out by directing a first and second beam of x-rays into the mixture. The process includes transmitting x-rays directly to detectors to set one criterion, shielding the detectors from the x-ray sources to set another criterion and then passing samples of known relative composition to provide data for storage and calibration carrying out the process of mixtures to be measured

  13. A spectrometric approach in radiography for detection of materials by their effective atomic number

    CERN Document Server

    Ryzhikov, V D; Onyshchenko, G M; Lecoq, P; Smith, C F

    2009-01-01

    In this paper we report a spectrometric approach to dual-energy digital radiography that has been developed and applied to identify specific organic substances and discern small differences in their effective atomic number. An experimental setup has been designed, and a theoretical description proposed based on the experimental results obtained. The proposed method is based on the application of special reference samples made of materials with different effective atomic number and thickness parameters known to affect X-ray attenuation in the low-energy range. The results obtained can be used in the development of a new generation of multi-energy customs or medical X-ray scanners.

  14. Direct reconstruction of the effective atomic number of materials by the method of multi-energy radiography

    International Nuclear Information System (INIS)

    Naydenov, Sergey V.; Ryzhikov, Vladimir D.; Smith, Craig F.

    2004-01-01

    A direct method is proposed for reconstruction of the effective atomic number by means of multi-energy radiography of the material. The accuracy of the method is up to 95%. Advantages over conventional radiographic methods, which ensure accuracy of just about 50%, are discussed. A physical model has been constructed and general expressions have been obtained for description of the effective atomic number in a two-energy monitoring scheme. A universal dependence has been predicted for the effective atomic number as a function of relative (two-energy) radiographic reflex. The established theoretical law is confirmed by the experimental data presented. The proposed development can find multiple applications in non-destructive testing and related fields, including those in the civil sphere as well as anti-terrorist activities

  15. Direct reconstruction of the effective atomic number of materials by the method of multi-energy radiography

    Science.gov (United States)

    Naydenov, Sergey V.; Ryzhikov, Vladimir D.; Smith, Craig F.

    2004-02-01

    A direct method is proposed for reconstruction of the effective atomic number by means of multi-energy radiography of the material. The accuracy of the method is up to 95%. Advantages over conventional radiographic methods, which ensure accuracy of just about 50%, are discussed. A physical model has been constructed and general expressions have been obtained for description of the effective atomic number in a two-energy monitoring scheme. A universal dependence has been predicted for the effective atomic number as a function of relative (two-energy) radiographic reflex. The established theoretical law is confirmed by the experimental data presented. The proposed development can find multiple applications in non-destructive testing and related fields, including those in the civil sphere as well as anti-terrorist activities.

  16. Computed phase equilibria for burnable neutron absorbing materials for advanced pressurized heavy water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Corcoran, E.C. [Department of Chemistry and Chemical Engineering, Royal Military College of Canada, P.O. Box 17000, St. Forces, Kingston, Ont., K7K 7B4 (Canada)], E-mail: emily.corcoran@rmc.ca; Lewis, B.J.; Thompson, W.T. [Department of Chemistry and Chemical Engineering, Royal Military College of Canada, P.O. Box 17000, St. Forces, Kingston, Ont., K7K 7B4 (Canada); Hood, J. [Atomic Energy of Canada Ltd., Sheridan Park, 2251 Speakman Drive, Mississauga, Ont., L5K 1B2 (Canada); Akbari, F.; He, Z. [Atomic Energy of Canada Ltd., Chalk River Laboratories, Chalk River, Ont., K0J 1J0 (Canada); Reid, P. [Atomic Energy of Canada Ltd., Sheridan Park, 2251 Speakman Drive, Mississauga, Ont., L5K 1B2 (Canada)

    2009-03-31

    Burnable neutron absorbing materials are expected to be an integral part of the new fuel design for the Advanced CANDU [CANDU is as a registered trademark of Atomic Energy of Canada Limited.] Reactor. The neutron absorbing material is composed of gadolinia and dysprosia dissolved in an inert cubic-fluorite yttria-stabilized zirconia matrix. A thermodynamic model based on Gibbs energy minimization has been created to provide estimated phase equilibria as a function of composition and temperature. This work includes some supporting experimental studies involving X-ray diffraction.

  17. Effective atomic number of dental smalt

    International Nuclear Information System (INIS)

    Rodas D, J.E.; Nogueira, M.S.

    1998-01-01

    The effective atomic numbers Z are enough utilized for to characterize the interactions of ionizing radiation with matter. Particularly for the Z calculation in biological tissues and/or composed materials we need to know the relationship between the cross sections of the diverse radiations interactions with mattera and the atomic numbers Z of the constituent elements in the tissue or composed material. Normally the cross section by atom σ 2 is proportional to Z m . The m value depends of the iterative process type and the energy of the incident photons. In the case of the photoelectric interaction, the m vary will vary between 4,698 and 4,799 for energies between 10 to 200 keV. It was verified that constituent elements with high Z (>20) they had a major contribution. The m values for the Compton interation and the coherent scattering were calculated of similar way. Knowing the m values, we calculate the partials Z of a composed material. For the calculation of total Z, we can use alternatives starting from the equivalent atomic number corresponding to the total cross section σ d tot, mc of the composed material. In this work for the calculation of Z values corresponding to diverse interations, we applied a linear regression at the values of Ln σ a x LnZ for different energies. In general, to characterize a simulator material of a tissue or composed material we need to know the total Z in function of the photon energy applied to dental smalt increases until some hundreds of keV the partial values of Z owing to photoelectric effect and the coherent scattering this is owing to the smalt has a great concentration of elements with high Z. (Author)

  18. A state-of-the-art report on the development of B{sub 4}C materials as neutron absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Choong Hwan; Kim, Sun Jae; Park, Jee Yun; Kang, Dae Kab [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1994-01-01

    Boron of 10 atomic weight is one of the best neutron absorbing elements. Among the boron compounds, B{sub 4}C and its composites exhibit excellent material properties. Those materials absorb thermal and fast neutrons, are thermally and chemically very stable, and are very strong in mechanical properties. By neutron irradiation B-10 transforms into Li releasing one He atom. This He release causes swelling, cracking and fragmentation of B{sub 4}C bulks and results in degradation of the materials. The essence of technical developments of B{sub 4}C-based neutron absorbers is the minimization of the effects of He release, and this can be realized through microstructural optimizations of grain and porosity distributions. While pure B{sub 4}C is very difficult in sintering, new neutron absorbing materials of B{sub 4}C-cermets are being developed. B{sub 4}C-cermets are composite materials in which B{sub 4}C powders are dispersed in the metal matrix of Al or Cu. Those materials show easiness in sintering, mechanical forming, and B{sub 4}C content controlling. Neutron absorbing and shielding materials play an important role for the safety of reactor operations and environmental protections. Those materials are being used as monolithic pellets for control rods, burnable poison fuel rods, rack materials for spent fuel storages, shielding materials for shipping casks, and especially for shielding plates for liquid metal reactors. 37 figs., 12 tabs., 41 refs. (Author).

  19. Effective atomic numbers and effective electron densities for trommel sieve waste and some commonly used building materials

    International Nuclear Information System (INIS)

    Kurudirek, M.; Canimkurbey, B.; Coban, M.; Ayguen, M.; Erzeneoglu, S. Z.

    2010-01-01

    Trommel sieve waste and some commonly used building materials (Portland cement, lime and pointing) have been investigated in terms of effective atomic numbers (Z e ff) and effective electron densities (N e ) by using X- and γ- rays at 22.1, 25 and 88 keV photon energies. A high resolution Si(Li) detector was employed to detect X- and/or γ- radiation coming through in a narrow beam good geometry set-up. Chemical compositions of the materials used in the present study were determined using a wave length dispersive X-ray fluorescence spectrometer (WDXRFS). The variations in photon interaction parameters were discussed regarding the photon energy and chemical composition. The experimental values of effective atomic numbers and effective electron densities were compared with the ones obtained from theory.

  20. Tomography of atomic number and density of materials using dual-energy imaging and the Alvarez and Macovski attenuation model

    Energy Technology Data Exchange (ETDEWEB)

    Paziresh, M.; Kingston, A. M., E-mail: andrew.kingston@anu.edu.au; Latham, S. J.; Fullagar, W. K.; Myers, G. M. [Department of Applied Mathematics, Research School of physics and Engineering, The Australian National University, Canberra 2601 (Australia)

    2016-06-07

    Dual-energy computed tomography and the Alvarez and Macovski [Phys. Med. Biol. 21, 733 (1976)] transmitted intensity (AMTI) model were used in this study to estimate the maps of density (ρ) and atomic number (Z) of mineralogical samples. In this method, the attenuation coefficients are represented [Alvarez and Macovski, Phys. Med. Biol. 21, 733 (1976)] in the form of the two most important interactions of X-rays with atoms that is, photoelectric absorption (PE) and Compton scattering (CS). This enables material discrimination as PE and CS are, respectively, dependent on the atomic number (Z) and density (ρ) of materials [Alvarez and Macovski, Phys. Med. Biol. 21, 733 (1976)]. Dual-energy imaging is able to identify sample materials even if the materials have similar attenuation coefficients at single-energy spectrum. We use the full model rather than applying one of several applied simplified forms [Alvarez and Macovski, Phys. Med. Biol. 21, 733 (1976); Siddiqui et al., SPE Annual Technical Conference and Exhibition (Society of Petroleum Engineers, 2004); Derzhi, U.S. patent application 13/527,660 (2012); Heismann et al., J. Appl. Phys. 94, 2073–2079 (2003); Park and Kim, J. Korean Phys. Soc. 59, 2709 (2011); Abudurexiti et al., Radiol. Phys. Technol. 3, 127–135 (2010); and Kaewkhao et al., J. Quant. Spectrosc. Radiat. Transfer 109, 1260–1265 (2008)]. This paper describes the tomographic reconstruction of ρ and Z maps of mineralogical samples using the AMTI model. The full model requires precise knowledge of the X-ray energy spectra and calibration of PE and CS constants and exponents of atomic number and energy that were estimated based on fits to simulations and calibration measurements. The estimated ρ and Z images of the samples used in this paper yield average relative errors of 2.62% and 1.19% and maximum relative errors of 2.64% and 7.85%, respectively. Furthermore, we demonstrate that the method accounts for the beam hardening effect in density (

  1. Neutron Absorbing Ability Variation in Neutron Absorbing Material Caused by the Neutron Irradiation in Spent Fuel Storage Facility

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, Hee Dong; Han, Seul Gi; Lee, Sang Dong; Kim, Ki Hong; Ryu, Eag Hyang; Park, Hwa Gyu [Doosan Heavy Industries and Construction, Changwon (Korea, Republic of)

    2014-10-15

    In spent fuel storage facility like high density spent fuel storage racks and dry storage casks, spent fuels are stored with neutron absorbing materials installed as a part of those facilities, and they are used for absorbing neutrons emitted from spent fuels. Usually structural material with neutron absorbing material of racks and casks are located around spent fuels, so it is irradiated by neutrons for long time. Neutron absorbing ability could be changed by the variation of nuclide composition in neutron absorbing material caused by the irradiation of neutrons. So, neutron absorbing materials are continuously faced with spent fuels with boric acid solution or inert gas environment. Major nuclides in neutron absorbing material are Al{sup 27}, C{sup 12}, B{sup 11}, B{sup 10} and they are changed to numerous other ones as radioactive decay or neutron absorption reaction. The B{sup 10} content in neutron absorbing material dominates the neutron absorbing ability, so, the variation of nuclide composition including the decrease of B{sup 10} content is the critical factor on neutron absorbing ability. In this study, neutron flux in spent fuel, the activation of neutron absorbing material and the variation of nuclide composition are calculated. And, the minimum neutron flux causing the decrease of B{sup 10} content is calculated in spent fuel storage facility. Finally, the variation of neutron multiplication factor is identified according to the one of B{sup 10} content in neutron absorbing material. The minimum neutron flux to impact the neutron absorbing ability is 10{sup 10} order, however, usual neutron flux from spent fuel is 10{sup 8} order. Therefore, even though neutron absorbing material is irradiated for over 40 years, B{sup 10} content is little decreased, so, initial neutron absorbing ability could be kept continuously.

  2. Atomic Fisher information versus atomic number

    International Nuclear Information System (INIS)

    Nagy, A.; Sen, K.D.

    2006-01-01

    It is shown that the Thomas-Fermi Fisher information is negative. A slightly more sophisticated model proposed by Gaspar provides a qualitatively correct expression for the Fisher information: Gaspar's Fisher information is proportional to the two-third power of the atomic number. Accurate numerical calculations show an almost linear dependence on the atomic number

  3. Transition metal atoms absorbed on MoS2/h-BN heterostructure: stable geometries, band structures and magnetic properties.

    Science.gov (United States)

    Wu, Yanbing; Huang, Zongyu; Liu, Huating; He, Chaoyu; Xue, Lin; Qi, Xiang; Zhong, Jianxin

    2018-06-15

    We have studied the stable geometries, band structures and magnetic properties of transition-metal (V, Cr, Mn, Fe, Co and Ni) atoms absorbed on MoS2/h-BN heterostructure systems by first-principles calculations. By comparing the adsorption energies, we find that the adsorbed transition metal (TM) atoms prefer to stay on the top of Mo atoms. The results of the band structure without spin-orbit coupling (SOC) interaction indicate that the Cr-absorbed systems behave in a similar manner to metals, and the Co-absorbed system exhibits a half-metallic state. We also deduce that the V-, Mn-, Fe-absorbed systems are semiconductors with 100% spin polarization at the HOMO level. The Ni-absorbed system is a nonmagnetic semiconductor. In contrast, the Co-absorbed system exhibits metallic state, and the bandgap of V-absorbed system decreases slightly according to the SOC calculations. In addition, the magnetic moments of all the six TM atoms absorbed on the MoS2/h-BN heterostructure systems decrease when compared with those of their free-standing states.

  4. Enhancement of the atomic absorbance of Cr, Zn, Cd, and Pb in metal furnace atomic absorption spectrometry using absorption tubes

    Directory of Open Access Journals (Sweden)

    Yuya Koike

    2017-03-01

    Full Text Available Trace amounts of Cr, Zn, Cd, and Pb were determined by metal furnace atomic absorption spectrometry using absorption tubes. Various absorption tubes were designed as roof- and tube-types, and fixed above the metal furnace in order to extend the light path length. Aqueous standards and samples were injected in the metal furnace and atomized in a metal atomizer with an absorption tube (6 cm length, 15.5 mm diameter. The used of an absorption tube resulted in an enhancement of the atomic absorbance. The ratios of absorbance values with and without the roof- and tube-type absorption tubes were 1.33 and 1.11 for Cr; 1.42 and 1.99 for Zn; 1.66 and 1.98 for Cd; and 1.31 and 1.16 for Pb, respectively. The use of an absorption tube was effective for Zn and Cd analysis, as the absorbance values for these low boiling point metals doubled. The proposed method was successfully applied in the determination of Zn in tap water.

  5. Calculation of radiation attenuation coefficients, effective atomic numbers and electron densities for some building materials

    International Nuclear Information System (INIS)

    Damla, N.; Baltas, H.; Celik, A.; Kiris, E.; Cevik, U.

    2008-01-01

    Some building materials, regularly used in Turkey, such as sand, cement, gas concrete (lightweight, aerated concrete), tile and brick, have been investigated in terms of mass attenuation coefficient, effective atomic, numbers (Z eff ), effective electron densities (N e ) and photon interaction cross section (σ a ) at 14 different energies from 81- to 1332-keV gamma-ray energies. The gamma rays were detected by using gamma-ray spectroscopy, a High Purity Germanium (HPGe) detector. The elemental compositions of samples were analysed using an energy dispersive X-ray fluorescence spectrometer. Mass attenuation coefficients of these samples have been compared with tabulations based upon the results of WinXcom. The theoretical mass attenuation coefficients were estimated using the mixture rule and the experimental values of investigated parameters were compared with the calculated values. The agreement of measured values of mass attenuation coefficient, effective atomic numbers, effective electron densities and photon interaction cross section with the theory has been found to be quite satisfactory. (authors)

  6. Characterization of weak, fair and strong neutron absorbing materials by means of neutron transmission: Beam hardening effect

    Science.gov (United States)

    Kharfi, F.; Bastuerk, M.; Boucenna, A.

    2006-09-01

    The characterization of neutron absorbing materials as well as quantification of neutron attenuation through matter is very essential in various fields, namely in shielding calculation. The objective of this work is to describe an experimental procedure to be used for the determination of neutron transmission through different materials. The proposed method is based on the relation between the gray value measured on neutron radiography image and the corresponding inducing neutron beam. For such a purpose, three kinds of materials (in shape of plate) were investigated using thermal neutrons: (1) boron-alloyed stainless steel as strong absorber; (2) copper and steel as fair absorbers and (3) aluminum as weak absorber. This work is not limited to the determination of neutron transmission through matters; it is also spread out to the measure of the surface density of the neutron absorbing elements (ρs) as a function of thickness of neutron absorbing material such as boron-alloyed stainless steel. The beam hardening effect depending on material thickness was also studied using the neutron transmission measurements. A theoretical approach was used to interpret the experimental results. The neutron transmission measurements were performed at the Neutron Radiography and Tomography facility of the Atomic Institute of the Austrian Universities in Vienna. Finally, a Maxwellian neutron distribution of incident neutron beam was used in the theoretical calculations of neutron energy shift in order to compare with experiments results. The obtained experimental results are in a good agreement with the developed theoretical approach.

  7. Absorber materials in CANDU PHWR's

    International Nuclear Information System (INIS)

    Price, E.G.; Boss, C.R.; Novak, W.Z.; Fong, R.W.L.

    1995-03-01

    In a CANDU reactor the fuel channels are arranged on a square lattice in a calandria filled with heavy water moderator. This arrangement allows five types of tubular neutron absorber devices to be located in a relatively benign environment of low pressure, low temperature heavy water between neighbouring rows of columns of fuel channels. This paper will describe the roles of the devices and outline the design requirements of the absorber component from a reactor physics viewpoint. Nuclear heating and activation problems associated with the different absorbers will be briefly discussed. The design and manufacture of the devices will be also discussed. The control rod absorbers and shut off materials are cadmium and stainless steel. In the tubular arrangement, the cadmium is sandwiched between stainless steel tubes. This type of device has functioned well, but there is now concern over the availability and expense of cadmium which is used in two types of CANDU control devices. There are also concerns about the toxicity of cadmium during the fabrication of the absorbers. These concerns are prompting AECL to study alternatives. To minimize design changes, pure boron-10 alloyed in stainless steel is a favoured option. Work is underway to confirm the suitability of the boron-loaded steel and identify other encapsulated absorber materials for practical application. Because the reactivity devices or their guide tubes span the calandria vessel, the long slender components must be sufficiently rigid to resist operational vibration and also be seismically stable. Some of these components are made of Zircaloy to minimize neutron absorption. Slow irradiation growth and creep can reduce the spring tension, and periodic adjustments to the springs are required. Experience with the control absorber devices has generally been good. In one instance liquid zone controllers had a problem of vibration induced fretting but a designed back-fit resolved the problem. (author). 3 refs., 1

  8. Development of highly effective neutron shields and neutron absorbing materials

    International Nuclear Information System (INIS)

    Tsuda, K.; Matsuda, F.; Taniuchi, H.; Yuhara, T.; Iida, T.

    1993-01-01

    A wide range of materials, including polymers and hydrogen-occluded alloys that might be usable as the neutron shielding material were examined. And a wide range of materials, including aluminum alloys that might be usable as the neutron-absorbing material were examined. After screening, the candidate material was determined on the basis of evaluation regarding its adaptabilities as a high-performance neutron-shielding and neutron-absorbing material. This candidate material was manufactured for trial, after which material properties tests, neutron-shielding tests and neutron-absorbing tests were carried out on it. The specifications of this material were thus determined. This research has resulted in materials of good performance; a neutron-shielding material based on ethylene propylene rubber and titanium hydride, and a neutron-absorbing material based on aluminum and titanium hydride. (author)

  9. A high absorbance material for solar collectors' applications

    International Nuclear Information System (INIS)

    Oliva, A I; Maldonado, R D; Díaz, E A; Montalvo, A I

    2013-01-01

    In this work, we proposed a low cost material to be used as an excellent absorber for solar collectors, to increase its thermal efficiency by the high capacity to absorb solar radiation. The material, known as 'smoke black' (soot) can be obtained by the incomplete combustion of organic materials, such as the oxygen-acetylene, paraffin, or candles. A comparative analysis between the optical properties (reflectance, absorbance, and emissivity) measured on three covered copper surfaces (without paint, with a commercial matte black paint, and with smoke black) shows amazing optical results for the smoke black. Reflectance values of the smoke black applied over copper surfaces improves 56 times the values obtained from commercial black paints. High values of emissivity (E=0.9988) were measured on the surface covered with smoke black by spectrophotometry in the UV-VIS range, which represents about 7% of increment as compared with the value obtained for commercial black paints (E=0.938). The proposed high absorbance material can be easily applied on any kind of surfaces at low cost.

  10. Phonon interference control of atomic-scale metamirrors, meta-absorbers, and heat transfer through crystal interfaces

    Science.gov (United States)

    Kosevich, Yu. A.; Potyomina, L. G.; Darinskii, A. N.; Strelnikov, I. A.

    2018-03-01

    The paper theoretically studies the possibility of using the effects of phonon interference between paths through different interatomic bonds for the control of phonon heat transfer through internal crystal interfaces and for the design of phonon metamirrors and meta-absorbers. These metamirrors and meta-absorbers are considered to be defect nanolayers of atomic-scale thicknesses embedded in a crystal. Several analytically solvable three-dimensional lattice-dynamics models of the phonon metamirrors and meta-absorbers at the internal crystal planes are described. It is shown that due to destructive interference in the two or more phonon paths, the internal crystal planes, fully or partially filled with weakly bound or heavy-isotope defect atoms, can completely reflect or completely absorb phonons at the transmission antiresonances, whose wavelengths are larger than the effective thickness of the metamirror or meta-absorber. Due to cooperative superradiant effect, the spectral widths of the two-path interference antiresonances for the plane waves are given by the square of partial filling fraction in the defect crystal plane. Our analysis reveals that the presence of two or more phonon paths plays the dominant role in the emergence of the transmission antiresonances in phonon scattering at the defect crystal planes and in reduction of the thermal interface conductance in comparison with the Fano-resonance concept. We study analytically phonon transmission through internal crystal plane in a model cubic lattice of Si-like atoms, partially filled with Ge-like defect atoms. Such a plane can serve as interference phonon metamirror with the transmission antiresonances in the vicinities of eigenmode frequencies of Ge-like defect atoms in the terahertz frequency range. We predict the extraordinary phonon transmission induced by the two-path constructive interference of the lattice waves in resonance with the vibrations of rare host atoms, periodically distributed in the

  11. Effective atomic numbers in some food materials and medicines for γ -ray attenuation using ^{137}Cs γ -ray

    Science.gov (United States)

    Revathy, J. S.; Anooja, J.; Krishnaveni, R. B.; Gangadathan, M. P.; Varier, K. M.

    2018-06-01

    A light-weight multichannel analyser (MCA)-based γ -ray spectrometer, developed earlier at the Inter University Accelerator Centre, New Delhi, has been used as part of the PG curriculum, to determine the effective atomic numbers for γ attenuation of ^{137}Cs γ -ray in different types of samples. The samples used are mixtures of graphite, aluminum and selenium powders in different proportions, commercial and home-made edible powders, fruit and vegetable juices as well as certain allopathic and ayurvedic medications. A narrow beam good geometry set-up has been used in the experiments. The measured attenuation coefficients have been used to extract effective atomic numbers in the samples. The results are consistent with XCOM values wherever available. The present results suggest that the γ attenuation technique can be used as an effective non-destructive method for finding adulteration of food materials.

  12. Development of Coatings for Radar Absorbing Materials at X-band

    Science.gov (United States)

    Kumar, Abhishek; Singh, Samarjit

    2018-03-01

    The present review gives a brief account on some of the technical features of radar absorbing materials (RAMs). The paper has been presented with a concentrated approach towards the material aspects for achieving enhanced radar absorption characteristics for its application as a promising candidate in stealth technology and electromagnetic interference (EMI) minimization problems. The effect of metal particles doping/dispersion in the ferrites and dielectrics has been discussed for obtaining tunable radar absorbing characteristics. A short theoretical overview on the development of absorber materials, implementation of genetic algorithm (GA) in multi-layering and frequency selective surfaces (FSSs) based multi-layer has also been presented for the development of radar absorbing coatings for achieving better absorption augmented with broadband features in order to counter the radar detection systems.

  13. Absorber Materials for Transition-Edge Sensor X-ray Microcalorimeters

    Science.gov (United States)

    Brown, Ari-David; Bandler, Simon; Brekosky, Regis; Chervenak, James; Figueroa-Feliciano, Enectali; Finkbeiner, Fred; Sadleir, Jack; Iyomoto, Naoko; Kelley, Richard; Kilbourne, Caroline; hide

    2007-01-01

    Arrays of superconducting transition-edge sensors (TES) can provide high spatial and energy resolution necessary for x-ray astronomy. High quantum efficiency and uniformity of response can be achieved with a suitable absorber material, in which absorber x-ray stopping power, heat capacity, and thermal conductivity are relevant parameters. Here we compare these parameters for bismuth and gold. We have fabricated electroplated gold, electroplated gold/electroplated bismuth, and evaporated gold/evaporated bismuth 8x8 absorber arrays and find that a correlation exists between the residual resistance ratio (RRR) and thin film microstructure. This finding indicates that we can tailor absorber material conductivity via microstructure alteration, so as to permit absorber thermalization on timescales suitable for high energy resolution x-ray microcalorimetry. We show that by incorporating absorbers possessing large grain size, including electroplated gold and electroplated gold/electroplated bismuth, into our current Mo/Au TES, devices with tunable heat capacity and energy resolution of 2.3 eV (gold) and 2.1 eV (gold/bismuth) FWHM at 6 keV have been fabricated.

  14. A new neutron absorber material for criticality control

    International Nuclear Information System (INIS)

    Wells, Alan H.

    2007-01-01

    A new neutron absorber material based on a nickel metal matrix composite has been developed for applications such as the Transport, Aging, and Disposal (TAD) canister for the Yucca Mountain Project. This new material offers superior corrosion resistance to withstand the more demanding geochemical environments found in a 300,000 year to a million year repository. The lifetime of the TAD canister is currently limited to 10,000 years, reflecting the focus of current regulations embodied in 10 CFR 63. The use of DOE-owned nickel stocks from decommissioned enrichment facilities could reduce the cost compared to stainless steel/boron alloy. The metal matrix composite allows the inclusion of more than one neutron absorber compound, so that the exact composition may be adjusted as needed. The new neutron absorber material may also be used for supplementary criticality control of stored or transported PWR spent fuel by forming it into cylindrical pellets that can be inserted into a surrogate control rod. (authors)

  15. Materials selection for long life in LEO: a critical evaluation of atomic oxygen testing with thermal atom systems

    International Nuclear Information System (INIS)

    Koontz, S.L.; Kuminecz, J.; Leger, L.; Nordine, P.

    1988-01-01

    The use of thermal atom test methods as a materials selection and screening technique for low-Earth orbit (LEO) spacecraft is critically evaluated. The chemistry and physics of thermal atom environments are compared with the LEO environment. The relative reactivities of a number of materials determined to be in thermal atom environments are compared to those observed in LEO and in high quality LEO simulations. Reaction efficiencies measured in a new type of thermal atom apparatus are one-hundredth to one-thousandth those observed in LEO, and many materials showing nearly identical reactivities in LEO show relative reactivities differing by as much as a factor of 8 in thermal atom systems. A simple phenomenological kinetic model for the reaction of oxygen atoms with organic materials can be used to explain the differences in reactivity in different environments. Certain specific thermal test environments can be used as reliable materials screening tools. Using thermal atom methods to predict material lifetime in LEO requires direct calibration of the method against LEO data or high quality simulation data for each material

  16. "Material interactions": from atoms & bits to entangled practices

    DEFF Research Database (Denmark)

    Vallgårda, Anna

    and intellectually stimulating panel moderated by Prof. Mikael Wiberg consisting of a number of scholars with a well-developed view on digital materialities to fuel a discussion on material interactions - from atoms & bits to entangled practices. These scholars include: Prof. Hiroshi Ishii, Prof. Paul Dourish...

  17. Effect of low-Z absorber's thickness on gamma-ray shielding parameters

    Energy Technology Data Exchange (ETDEWEB)

    Mann, Kulwinder Singh, E-mail: ksmann6268@gmail.com [Department of Applied Sciences, Punjab Technical University, Kapurthala 144601 (India); Department of Physics, D.A.V. College, Bathinda 151001, Punjab (India); Heer, Manmohan Singh [Department of Physics, Kanya Maha Vidyalaya, Jalandhar 144001 (India); Rani, Asha [Department of Applied Sciences, Ferozpur College of Engineering and Technology, Ferozshah, Ferozpur 142052 (India)

    2015-10-11

    Gamma ray shielding behaviour of any material can be studied by various interaction parameters such as total mass attenuation coefficient (μ{sub m}); half value layer (HVL); tenth value layer (TVL); effective atomic number (Z{sub eff}), electron density (N{sub el}), effective atomic weight (A{sub eff}) and buildup factor. For gamma rays, the accurate measurements of μ{sub m} (cm{sup 2} g{sup −1}) theoretically require perfect narrow beam irradiation geometry. However, the practical geometries used for the experimental investigations deviate from perfect-narrowness thereby the multiple scattered photons cause systematic errors in the measured values of μ{sub m}. Present investigation is an attempt to find the optimum value of absorber thickness (low-Z) for which these errors are insignificant and acceptable. Both experimental and theoretical calculations have been performed to investigate the effect of absorber's thickness on μ{sub m} of six low-Z (10materials (cement-black; cement-white; clay; red-mud; lime-stone and plaster of paris) at gamma-ray energies 661.66 keV, 1173.24 keV and 1332.50 keV. A computer program (GRIC2-toolkit) was designed for theoretical evaluation of shielding parameters of any material. Good agreement of theoretical and measured values of μ{sub m} was observed for all absorbers with thickness ≤0.5 mean free paths, thus considered it as optimum thickness for low-Z materials in the selected energy range. White cement was found to possess maximum shielding effectiveness for the selected gamma rays. - Highlights: • Optimum thickness value is 0.5 mfp for low-Z absorbers in energy range 662–1332 keV. • For accurate measurement of μ{sub m} absorber's thickness should be ≤optimum thickness. • GRIC2-toolkit is useful for γ-ray shielding analysis of composite materials.

  18. Spectral effects on some physical coefficients of x-Ray interaction with materials of low atomic number

    International Nuclear Information System (INIS)

    EL-Kazzaz, S.A.; Youssef, M.; EL-Hadad, S.; and EL-Nadi, L.M.

    1988-01-01

    X-ray spectra were measured before and after passing through some materials of medical importance applying X-ray diffraction. The mass absorption coefficients of these materials were determined at X-ray peak voltages 27, 30 and 42 kV-p making use the measured spectrum and also by using the direct beam absorption. It has been found that the mass absorption coefficients calculated from the X-ray spectral distribution analysis are in general lower than those obtained considering the direct beam method. From the study of the atomic number and energy dependence of the mass absorption coefficients it has been found that the dependence of the coefficients calculated from the spectral distribution is good agreement with the previously studied data for monoenergetic x-ray beam. Also the roentgen - to - Rad conversion factors were determined at the different used energies and materials. The value of the mass absorption coefficients calculated from the spectral distribution is recommended for use in dose calculation

  19. Effective atomic number of dental smalt; Numero atomico efetivo do esmalte dentario

    Energy Technology Data Exchange (ETDEWEB)

    Rodas D, J.E.; Nogueira, M.S. [Departamento de Fisica e Matematica da FFCLRP-USP. 14040-901 Ribeirao Preto, Sao Paulo (Brazil)

    1998-12-31

    The effective atomic numbers Z are enough utilized for to characterize the interactions of ionizing radiation with matter. Particularly for the Z calculation in biological tissues and/or composed materials we need to know the relationship between the cross sections of the diverse radiations interactions with mattera and the atomic numbers Z of the constituent elements in the tissue or composed material. Normally the cross section by atom {sigma} {sup 2} is proportional to Z{sup m}. The m value depends of the iterative process type and the energy of the incident photons. In the case of the photoelectric interaction, the m vary will vary between 4,698 and 4,799 for energies between 10 to 200 keV. It was verified that constituent elements with high Z (>20) they had a major contribution. The m values for the Compton interation and the coherent scattering were calculated of similar way. Knowing the m values, we calculate the partials Z of a composed material. For the calculation of total Z, we can use alternatives starting from the equivalent atomic number corresponding to the total cross section {sigma} {sup d} tot, mc of the composed material. In this work for the calculation of Z values corresponding to diverse interations, we applied a linear regression at the values of Ln {sigma} {sup a} x LnZ for different energies. In general, to characterize a simulator material of a tissue or composed material we need to know the total Z in function of the photon energy applied to dental smalt increases until some hundreds of keV the partial values of Z owing to photoelectric effect and the coherent scattering this is owing to the smalt has a great concentration of elements with high Z. (Author)

  20. Knitted radar absorbing materials (RAM) based on nickel–cobalt magnetic materials

    International Nuclear Information System (INIS)

    Teber, Ahmet; Unver, Ibrahim; Kavas, Huseyin; Aktas, Bekir; Bansal, Rajeev

    2016-01-01

    There has been a long-standing interest in the development of flexible, lightweight, thin, and reconfigurable radar absorbing materials (RAM) for military applications such as camouflaging ground-based hardware against airborne radar observation. The use of polymeric Polyacrylonitrile (PAN) fabrics as a host matrix for magnetic metal nano-particles (either at the yarn-stage or after weaving the fabric) for shielding and absorbing applications has been described in the literature. In our experimental investigation, the relative concentrations of Nickel and Cobalt as well as the coating time are varied with a view to optimizing the microwave absorption characteristics of the resulting PAN-based composite material in the radar-frequency bands (X, K_u, and K). It is found that the PAN samples with the shortest coating time have the best return losses (under −20 dB return loss over a moderate bandwidth). - Graphical abstract: Here, we added the graphical abstract that provides summary the contents of the article in a concise pictorial form. - Highlights: • Flexible lightweight, thin, reconfigurable radar absorbing materials are proposed. • Polyacrylonitrile (PAN) fabrics are coated with nickel, cobalt magnetic materials. • The coating times affects microwave constitutive parameters and absorption. • Microwave absorption measurements were done via transmission line technique. • Microwave absorption is due to dielectric losses rather than magnetic losses.

  1. Knitted radar absorbing materials (RAM) based on nickel–cobalt magnetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Teber, Ahmet, E-mail: aht10003@engr.uconn.edu [Department of Electrical and Computer Engineering, University of Connecticut, Storrs, CT 06269 (United States); Unver, Ibrahim, E-mail: iunver@gtu.edu.tr [Department of Physics, Gebze Technical University, Kocaeli 41400 (Turkey); Kavas, Huseyin, E-mail: huseyin.kavas@medeniyet.edu.tr [Department of Physics, Istanbul Medeniyet University, Istanbul 34000 (Turkey); Aktas, Bekir, E-mail: aktas@gtu.edu.tr [Department of Physics, Gebze Technical University, Kocaeli 41400 (Turkey); Bansal, Rajeev, E-mail: rajeev@engr.uconn.edu [Department of Electrical and Computer Engineering, University of Connecticut, Storrs, CT 06269 (United States)

    2016-05-15

    There has been a long-standing interest in the development of flexible, lightweight, thin, and reconfigurable radar absorbing materials (RAM) for military applications such as camouflaging ground-based hardware against airborne radar observation. The use of polymeric Polyacrylonitrile (PAN) fabrics as a host matrix for magnetic metal nano-particles (either at the yarn-stage or after weaving the fabric) for shielding and absorbing applications has been described in the literature. In our experimental investigation, the relative concentrations of Nickel and Cobalt as well as the coating time are varied with a view to optimizing the microwave absorption characteristics of the resulting PAN-based composite material in the radar-frequency bands (X, K{sub u}, and K). It is found that the PAN samples with the shortest coating time have the best return losses (under −20 dB return loss over a moderate bandwidth). - Graphical abstract: Here, we added the graphical abstract that provides summary the contents of the article in a concise pictorial form. - Highlights: • Flexible lightweight, thin, reconfigurable radar absorbing materials are proposed. • Polyacrylonitrile (PAN) fabrics are coated with nickel, cobalt magnetic materials. • The coating times affects microwave constitutive parameters and absorption. • Microwave absorption measurements were done via transmission line technique. • Microwave absorption is due to dielectric losses rather than magnetic losses.

  2. Wide band design on the scaled absorbing material filled with flaky CIPs

    Science.gov (United States)

    Xu, Yonggang; Yuan, Liming; Gao, Wei; Wang, Xiaobing; Liang, Zichang; Liao, Yi

    2018-02-01

    The scaled target measurement is an important method to get the target characteristic. Radar absorbing materials are widely used in the low detectable target, considering the absorbing material frequency dispersion characteristics, it makes designing and manufacturing scaled radar absorbing materials on the scaled target very difficult. This paper proposed a wide band design method on the scaled absorbing material of the thin absorption coating with added carbonyl iron particles. According to the theoretical radar cross section (RCS) of the plate, the reflection loss determined by the permittivity and permeability was chosen as the main design factor. Then, the parameters of the scaled absorbing materials were designed using the effective medium theory, and the scaled absorbing material was constructed. Finally, the full-size coating plate and scaled coating plates (under three different scale factors) were simulated; the RCSs of the coating plates were numerically calculated and measured at 4 GHz and a scale factor of 2. The results showed that the compensated RCS of the scaled coating plate was close to that of the full-size coating plate, that is, the mean deviation was less than 0.5 dB, and the design method for the scaled material was very effective.

  3. Microwave Absorbent Packaging Material from Composites Chitosan-Polyvinyl Alcohol Polymer

    Directory of Open Access Journals (Sweden)

    Bambang - Riyanto

    2014-11-01

    Full Text Available Microwave absorbent packaging materials currently tend to biomaterial. Chitosan is a dielectric biomaterial with polycationic properties. The aim of this study was to analyze characteristics of microwave absorbing packaging material made from composite chitosan-polyvinyl alcohol (PVA polymer. The ability of the packaging material to absorb microwave was determined by reflection loss measurement. Formed packaging prototype resembles as a thin transparent yellowish plastic with thickness (0.11-0.22 mm and the tensile strength (106.33±2.82-143.00±2.59 kPa. SEM analysis showed homogenous structure characterized by interaction between chitosan and PVA. Optimum absorption value was obtained from chitosan concentration of 1%, with average value of reflection loss was (-31.9289±4.0094 dB.Keywords: chitosan, material packaging, microwave, reflection loss

  4. Microwave Absorbent Packaging Material from Composites Chitosan-Polyvinyl Alcohol Polymer

    Directory of Open Access Journals (Sweden)

    Bambang - Riyanto

    2015-07-01

    Full Text Available Microwave absorbent packaging materials currently tend to biomaterial. Chitosan is a dielectric biomaterial with polycationic properties. The aim of this study was to analyze characteristics of microwave absorbing packaging material made from composite chitosan-polyvinyl alcohol (PVA polymer. The ability of the packaging material to absorb microwave was determined by reflection loss measurement. Formed packaging prototype resembles as a thin transparent yellowish plastic with thickness (0.11-0.22 mm and the tensile strength (106.33±2.82-143.00±2.59 kPa. SEM analysis showed homogenous structure characterized by interaction between chitosan and PVA. Optimum absorption value was obtained from chitosan concentration of 1%, with average value of reflection loss was (-31.9289±4.0094 dB.Keywords: chitosan, material packaging, microwave, reflection loss

  5. Method of absorbing UF6 from gaseous mixtures in alkamine absorbents

    International Nuclear Information System (INIS)

    Lafferty, R.H.; Smiley, S.H.; Radimer, K.J.

    1976-01-01

    A method is described for recovering UF 6 from gaseous mixtures by absorption in a liquid. The liquid absorbent must have a relatively low viscosity and at least one component of the absorbent is an alkamine having less than 3 carbon atoms bonded to the amino nitrogen, less than 2 of the carbon atoms other than those bonded to the amino nitrogen are free of the hydroxy radical and precipitate the absorbed uranium from the absorbent. At least one component of the absorbent is chosen from the group consisting of ethanolamine, diethanolamine, and 3-methyl-3-amino-propane-diol-1,2

  6. Electronic bandstructure of the ZnTe absorber material

    Energy Technology Data Exchange (ETDEWEB)

    Fritsch, Daniel [Leibniz Institute for Solid State and Materials Research IFW Dresden (Germany); Schmidt, Heidemarie [Forschungszentrum Dresden-Rossendorf, Dresden (Germany)

    2009-07-01

    Due to its large absorption coefficient, zinc telluride proved to be useful for the production of high-efficiency multi-junction solar cells. Nowadays ZnTe with a mixture of zincblende and wurtzite phases is fabricated by thin film growth techniques. The optical properties of both phases have been extensively studied by ab initio density functional methods. Here we focus on the question whether the effective electron and hole mass in ZnTe are small enough to meet the high-efficiency expectation of the ZnTe absorber material in solar cells and present direction dependent effective mass and Luttinger and Luttinger-like parameters of cubic and wurtzite ZnTe, respectively. Making use of the transferability of ionic model potential parameters and the experimentally known transition energies of different II-VI compounds ZnX (X=O,S,Se,Te), we obtained one single set of cationic model parameters for the Zn atom. The calculations have been performed by means of the empirical pseudopotential method using a simple empty core model potential.

  7. RF electromagnetic wave absorbing properties of ferrite polymer composite materials

    International Nuclear Information System (INIS)

    Dosoudil, Rastislav; Usakova, Marianna; Franek, Jaroslav; Slama, Jozef; Olah, Vladimir

    2006-01-01

    The frequency dispersion of complex initial (relative) permeability (μ * =μ ' -jμ ' ') and the electromagnetic wave absorbing properties of composite materials based on NiZn sintered ferrite and a polyvinylchloride (PVC) polymer matrix have been studied in frequency range from 1MHz to 1GHz. The complex permeability of the composites was found to increase as the ferrite content increased, and was characterized by frequency dispersion localized above 50MHz. The variation of return loss (RL) of single-layer RF absorbers using the prepared composite materials has been investigated as a function of frequency, ferrite content and the thickness of the absorbers

  8. Graphene Based Terahertz Absorber Designed With Effective Surface Conductivity Approach

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Pizzocchero, Filippo; Booth, Tim

    Young field of terahertz (THz) science and technology demands new materials and devices, such as filters, modulators, polarization converters and absorbers. Graphene, a recently discovered single-atom-thick material, provides exciting properties for functional terahertz applications. Graphene...... conductivity and how to use it in optical design. We demonstrate a tunable THz perfect absorber, which consists of continuous graphene various structured graphene metamaterials above a metal mirror. Changing the Fermi level from 0 eV to 0.5 eV allows for drastic changes in absorbance from less than 0.1 to 1...

  9. Design of broadband absorber using 2-D materials for thermo-photovoltaic cell application

    Science.gov (United States)

    Agarwal, Sajal; Prajapati, Y. K.

    2018-04-01

    Present study is done to analyze a nano absorber for thermo-photovoltaic cell application. Optical absorbance of two-dimensional materials is exploited to achieve high absorbance. It is found that few alternating layers of graphene/transition metal dichalcogenide provide high absorbance of electromagnetic wave in visible as well as near infrared region. Four transition metal dichalcogenides are considered and found that most of these provide perfect absorbance for almost full considered wavelength range i.e. 200-1000 nm. Demonstrated results confirm the extended operating region and improved absorbance of the proposed absorber in comparison to the existing absorbers made of different materials. Further, absorber performance is improved by using thin layers of gold and chromium. Simple geometry of the proposed absorber also ensures easy fabrication.

  10. On the effective atomic number and electron density: A comprehensive set of formulas for all types of materials and energies above 1 keV

    DEFF Research Database (Denmark)

    Manohara, S.R.; Hanagodimath, S.M.; Thind, K.S.

    2008-01-01

    A comprehensive and consistent set of formulas is given for calculating the effective atomic number and electron density for all types of materials and for all photon energies greater than 1 keV. The are derived from first principles using photon interaction cross sections of the constituent atom....... The theory is illustrated by calculations and experiments for molecules of medical and biological interest, glasses for radiation shielding, alloys, minerals and liquids....

  11. Porphyrin Based Near Infrared-Absorbing Materials for Organic Photovoltaics

    Science.gov (United States)

    Zhong, Qiwen

    photosynthesis. Photosynthesis uses light from the sun to drive a series of chemical reactions. Most natural photosynthetic systems utilize chlorophylls to absorb light energy and carry out photochemical charge separation that stores energy in the form of chemical bonds. The sun produces a broad spectrum of light output that ranges from gamma rays to radio waves. The entire visible range of light (400-700 nm) and some wavelengths in the NIR (700-1000 nm), are highly active in driving photosynthesis. Although the most familiar chlorophyll-containing organisms, such as plants, algae and cyanobacteria, cannot use light longer than 700 nm, anoxygenic bacterium containing bacteriochlorophylls can use the NIR part of the solar spectrum. No organism is known to utilize light of wavelength longer than about 1000 nm for photosynthesis. NIR light has a very low-energy content in each photon, so that large numbers of these low-energy photons would have to be used to drive the chemical reactions of photosynthesis. This is thermodynamically possible but would require a fundamentally different molecular mechanism that is more akin to a heat engine than to photochemistry. Early work on developing light absorbing materials for OPVs was inspired by photosynthesis in which light is absorbed by chlorophyll. Structurally related to chlorophyll is the porphyrin family, which has accordingly drawn much interest as the potential light absorbing component in OPV applications. In this dissertation, the design and detail studies of several porphyrin-based NIR absorbing materials, including pi--extended perylenyl porphryins and pyrazole-containing carbaporphyrins, as well as porphyrin modified single-walled carbon nanotube hybrids, will be presented, dedicating efforts to develop novel and application-oriented materials for efficient utilization of sustainable solar energy.

  12. Effect of different absorbing materials on the performance of basin solar still under Libyan climate conditions

    International Nuclear Information System (INIS)

    Shuia, Essaied M.; El-Agouz, Elsayed A.

    2013-01-01

    This experimental study deals with a single-basin solar still using various absorbing materials with and without black painting. Different types of absorbing materials with and without black painting were used to enhance the solar still productivity through improvement in absorptivity. These materials are steel and aluminum with and without black painting and rubber. Two identical solar stills were manufactured using locally available materials. All the results were compared together to reach the best absorbing materials with and without painting that can be used for solar still. it was found that the rubber absorber has the highest water collection during daytime, followed by the black painted steel absorber, then by black painted aluminum absorber and steel without painting absorber. The average enhancement in the daily productivity was about 50% for the rubber absorber compared with the black painted aluminum absorber and about 43% for the rubber absorber compared with the black painted steel absorber.(author)

  13. Characterization of rich in calcium materials using X-ray selective absorbers

    International Nuclear Information System (INIS)

    Guereca, G.; Ruvalcaba, J.L.

    2004-01-01

    For Particle Induced X-ray Emission Spectroscopy (PIXE) and X-ray Fluorescence Technique (FRX), the analysis of materials rich in one or two elements may present some difficulties due to high counting rates and saturation effects in X-ray detectors. In this case, it is possible to use selective absorbers in order to reduce the intensity of the major elements with low attenuation for the X-rays of other elements of the material. Using selective absorbers, the detection limits and the sensitivity are increased. For rich Ca materials (shells, bone, teeth and stucco, for instance), the high intensity of Ca X-rays interferes with the detection of lighter and heavier elements. Cl, Ar and Ag compounds are good candidates for Ca selective absorbers, but only Ag and Ar may have a practical absorber thickness. A selective absorber for Ca X-rays using a combination of thin Ag films and a flux of Ar and He was tested at the external beam setup of the Tandem Pelletron Accelerator for PIXE measurements. The improvement on elements detection on bone and colored stucco is shown. (Author) 8 refs., 2 tabs., 8 figs

  14. Strategy on biological evaluation for biodegradable/absorbable materials and medical devices.

    Science.gov (United States)

    Liu, Chenghu; Luo, Hongyu; Wan, Min; Hou, Li; Wang, Xin; Shi, Yanping

    2018-01-01

    During the last two decades, biodegradable/absorbable materials which have many benefits over conventional implants are being sought in clinical practices. However, to date, it still remains obscure for us to perform full physic-chemical characterization and biological risk assessment for these materials and related devices due to their complex design and coherent processing. In this review, based on the art of knowledge for biodegradable/absorbable materials and biological risk assessment, we demonstrated some promising strategies to establish and improve the current biological evaluation systems for these biodegradable/absorbable materials and related medical devices.

  15. Low atomic number coating for XEUS silicon pore optics

    DEFF Research Database (Denmark)

    Lumb, D.H.; Cooper-Jensen, Carsten P.; Krumrey, M.

    2008-01-01

    We describe a set of measurements on coated silicon substrates that are representative of the material to be used for the XEUS High Performance Pore Optics (HPO) technology. X-ray angular reflectance measurements at 2.8 and 8 keV, and energy scans of reflectance at a fixed angle representative...... of XEUS graze angles are presented. Reflectance is significantly enhanced for low energies when a low atomic number over-coating is applied. Modeling of the layer thicknesses and roughness is used to investigate the dependence on the layer thicknesses, metal and over coat material choices. We compare...

  16. Determination of atomic number and composition of human enamel

    International Nuclear Information System (INIS)

    Nogueira, M.S.; Rodas Duran, J.E.

    2001-01-01

    The teeth are organs of complicated structure that consist, partly, of hard tissue containing in its interior the dental pulp, rich in vases and nerves. The main mass of the tooth is constituted by the dentine, which is covered with hard tissues and of epithelial origin called enamel. The dentine of the human teeth used in this work were completely removed and the teeth were cut with a device with a diamond disc. In this work the chemical composition of the human enamel was determined, which showed a high percentage of Ca and P, in agreement with the results found in the literature. The effective atomic number of the material and the half-value layer in the energy range of diagnostic X-ray beams were determined. Teeth could be used to evaluated the public's individual doses as well as for retrospective dosimetry what confirms the importance of their effective atomic number and composition determination. (author)

  17. Concept of effective atomic number and effective mass density in dual-energy X-ray computed tomography

    International Nuclear Information System (INIS)

    Bonnin, Anne; Duvauchelle, Philippe; Kaftandjian, Valérie; Ponard, Pascal

    2014-01-01

    This paper focuses on dual-energy X-ray computed tomography and especially the decomposition of the measured attenuation coefficient in a mass density and atomic number basis. In particular, the concept of effective atomic number is discussed. Although the atomic number is well defined for chemical elements, the definition of an effective atomic number for any compound is not an easy task. After reviewing different definitions available in literature, a definition related to the method of measurement and X-ray energy, is suggested. A new concept of effective mass density is then introduced in order to characterize material from dual-energy computed tomography. Finally, this new concept and definition are applied on a simulated case, focusing on explosives identification in luggage

  18. Importance of the effective atomic number (Zeff) of TL materials for radiation dosimetry in clinical applications

    International Nuclear Information System (INIS)

    Gonzalez M, P.R.

    2008-01-01

    The electric power generation, it has been one of the radiation applications of bigger weight, mainly in developed countries. Another sector of more impact is without a doubt that of the medicine. However, for a sure operation with radiations, those international organisms of radiological safety, exist every time more precise detection systems. The thermoluminescent dosimetry is one of the more reliable methods for this purpose, for that several groups of investigators from different parts of the world, they have guided its investigations in the development of new TL materials. However, to avoid underestimate or overestimation of the measured dose with the use of these materials, it should take into account it effective atomic number (Z eff ) it is well known that some TL materials considered as equivalent to the tissue, presents smaller TL intensity when being irradiated with low energy photons, while the TL material known as not equivalent to the tissue, they present the supra sensitivity effect for this radiation type. Nowadays, the estimate of the Z eff has not been clear, in this work the Z eff is determined by means of the traditional methods and an own method is presented for its determination. The results of the TL signal of different materials, when being irradiated with photons of effective energy between 24 keV and 1.25 MeV and their relationship with their calculated Z eff are also presented. (Author)

  19. Optimization on microwave absorbing properties of carbon nanotubes and magnetic oxide composite materials

    Science.gov (United States)

    Mingdong, Chen; Huangzhong, Yu; Xiaohua, Jie; Yigang, Lu

    2018-03-01

    Based on the physical principle of interaction between electromagnetic field and the electromagnetic medium, the relationship between microwave absorbing coefficient (MAC) and the electromagnetic parameters of materials was established. With the composite materials of nickel ferrite (NiFe2O4), carbon nanotubes (CNTs) and paraffin as an example, optimization on absorbing properties of CNTs/magnetic oxide composite materials was studied at the frequency range of 2-18 GHz, and a conclusion is drawn that the MAC is the biggest at the same frequency, when the CNTs is 10 wt% in the composite materials. Through study on the relationship between complex permeability and MAC, another interesting conclusion is drawn that MAC is obviously affected by the real part of complex permeability, and increasing real part of complex permeability is beneficial for improving absorbing properties. The conclusion of this paper can provide a useful reference for the optimization research on the microwave absorbing properties of CNTs/ferrite composite materials.

  20. Determining the Absorbance Spectra of Photochromic Materials From Measured Spectrophotometer Data

    Science.gov (United States)

    Downie, John D.

    1998-01-01

    If a two-state photochromic material is optically bleached, the absorbance spectrum data measured by a spectrophotometer is in general comprised of components from both the ground state and the upper state. Under general conditions, it may be difficult to extract the actual upper state spectrum from the spectrum of the bleached material. A simple algorithm is presented here for the recovery of the pure absorbance spectra of the upper state of a material such as bacteriorhodopsin, given single wavelength bleaching illumination, steady-state conditions, and accurate knowledge of phototransition rates and thermal decay rates.

  1. Acoustic behavior of a fibrous bulk material. [Kevlar 29 sound absorber

    Science.gov (United States)

    Hersh, A. S.; Walker, B.

    1979-01-01

    A semiempirical model is presented describing the acoustic behavior of Kevlar 29, a bulk absorbing material. The model is based on an approximate solution to the one-dimensional equations representing conservation of fluctuating mass, momentum and energy. By treating the material as a momentum sink, theoretical expressions of the material complex propagation constants and characteristic impedance were derived in terms of a single constant. Evaluating the constant at a single frequency for a particular specimen, excellent agreement between prediction and measurement was achieved for a large range of sound frequencies and material porosities and thicknesses. Results show that Kevlar 29 absorbs sound efficiently even at low frequencies. This is explained in terms of a frequency dependent material phase speed.

  2. Moisture buffering capacity of highly absorbing materials

    Energy Technology Data Exchange (ETDEWEB)

    Cerolini, S.; D' Orazio, M.; Stazi, A. [Department of Architecture, Construction and Structures (DACS), Faculty of Engineering, Polytechnic University of Marche, Via Brecce Bianche, 60100 Ancona (Italy); Di Perna, C. [Department of Energetics, Faculty of Engineering, Polytechnic University of Marche, Via Brecce Bianche, 60100 Ancona (Italy)

    2009-02-15

    This research investigates the possibility to use highly absorbing materials to dampen indoor RH% variations. The practical MBV of sodium polyacrylate, cellulose-based material, perlite and gypsum is evaluated for a daily cyclic exposure that alternates high (75%) and low (33%) RH% levels for 8 h and 16 h, respectively. The adjustment velocity to RH% variations and the presence of hysteretic phenomena are also presented. The cellulose-based material proves to be the most suitable for moisture buffering applications. Starting from this material's properties, the effect of thickness, vapour resistance factor ({mu}) and mass surface exchange coefficient (Z{sub v}) on sorption capacity is evaluated by the use of a numerical model. (author)

  3. Excellent solar energy absorbing and retaining fabric material. Chikunetsu hoon sen'i sozai

    Energy Technology Data Exchange (ETDEWEB)

    Furuta, T. (Unitika Ltd., Osaka (Japan). Central Research Lab.)

    1993-11-10

    Carbides of group IV transition metals such as ZrC, which are used as solar energy selective absorption film for solar energy collectors, has characteristics of absorbing light with a high energy of 0.6eV or more and of converting it to heat when exposed to light, and of not absorbing but reflecting light with a low energy of less than 0.6eV. By using ZrC as fabric materials, therefore, portable and durable heat absorbing and retaining materials can be produced. The authors have developed a solar energy absorbing and retaining fabric material, 'Solar [alpha]' (registered trade mark), which absorbs visible and near infrared rays and converts them to heat, and reflects heat from a human body and confines it. The use of Solar [alpha] has been found in various fields such as clothing as a new material for winter-sportswear, slacks, coats, and swimming suits. In this report, the heat absorbing and retaining mechanisms, basic properties of Solar [alpha], and the results of wearing tests are described. 12 refs., 6 figs., 3 tabs.

  4. Energy Dependence of Measured CT Numbers on Substituted Materials Used for CT Number Calibration of Radiotherapy Treatment Planning Systems.

    Directory of Open Access Journals (Sweden)

    Reza Mahmoudi

    Full Text Available For accurate dose calculations, it is necessary to provide a correct relationship between the CT numbers and electron density in radiotherapy treatment planning systems (TPSs. The purpose of this study was to investigate the energy dependence of measured CT numbers on substituted materials used for CT number calibration of radiotherapy TPSs and the resulting errors in the treatment planning calculation doses.In this study, we designed a cylindrical water phantom with different materials used as tissue equivalent materials for the simulation of tissues and obtaining the related CT numbers. For evaluating the effect of CT number variations of substituted materials due to energy changing of scanner (kVp on the dose calculation of TPS, the slices of the scanned phantom at three kVp's were imported into the desired TPSs (MIRS and CorePLAN. Dose calculations were performed on two TPSs.The mean absolute percentage differences between the CT numbers of CT scanner and two treatment planning systems for all the samples were 3.22%±2.57% for CorePLAN and 2.88%±2.11% for MIRS. It was also found that the maximum absolute percentage difference between all of the calculated doses from each photon beam of linac (6 and 15 MV at three kVp's was less than 1.2%.The present study revealed that, for the materials with effective low atomic number, the mean CT number increased with increasing energy, which was opposite for the materials with an effective high atomic number. We concluded that the tissue substitute materials had a different behavior in the energy ranges from 80 to 130 kVp. So, it is necessary to consider the energy dependence of the substitute materials used for the measurement or calibration of CT number for radiotherapy treatment planning systems.

  5. X-ray absorption fine structure (XAFS) spectroscopy: a tool for structural studies in material sciences (abstract)

    International Nuclear Information System (INIS)

    Akhtar, M.J.

    2011-01-01

    XAFS spectroscopy has revealed itself as a powerful technique for structural characterization of the local atomic environment of individual atomic species, including bond distances, coordination numbers and type of nearest neighbors surrounding the central atom. This technique is particularly useful for materials that show considerable structural and chemical disorder. XAFS spectroscopy has found extensive applications in determining the local atomic and electronic structure of the absorbing centers (atoms) in the materials science, physics, chemistry, biology and geophysics. X-ray absorption edges contain a variety of information on the chemical state and the local structure of the absorbing atom. On the higher energy side of an absorption edge fine structure is observed due to backscattering of the emitted photoelectron. The post-edge region can be divided into two parts. The X-ray Absorption Near Edge Structure (XANES) which extends up to 50 eV of an absorption edge, the spectrum is interpreted in terms of the appropriate components of the local density of states, which would be expected to be sensitive to the valence state of the atom. The intensity, shape and location of the absorption edge features provide information on the valence state, electronic structure and coordination geometry of the absorbing atom.The Extended X-ray Absorption Fine Structure (EXAFS) region is dominated by the single scattering processes and extends up to 1000 eV above the edge and provides information on the radial distribution (coordination number, radial distance and type of neighboring atoms) around the central atom. The results on perovskite based and spinel ferrites systems will be presented, where valence state and cation distributions are determined; the present study will show focus on SrFeO/sub 3/, MnFe/sub 2/O/sub 4/ and Zn/sub 1-x/Ni/sub x/Fe/sub 2/O/sub 4/ materials. (author)

  6. Nanoarchitectonics for Controlling the Number of Dopant Atoms in Solid Electrolyte Nanodots.

    Science.gov (United States)

    Nayak, Alpana; Unayama, Satomi; Tai, Seishiro; Tsuruoka, Tohru; Waser, Rainer; Aono, Masakazu; Valov, Ilia; Hasegawa, Tsuyoshi

    2018-02-01

    Controlling movements of electrons and holes is the key task in developing today's highly sophisticated information society. As transistors reach their physical limits, the semiconductor industry is seeking the next alternative to sustain its economy and to unfold a new era of human civilization. In this context, a completely new information token, i.e., ions instead of electrons, is promising. The current trend in solid-state nanoionics for applications in energy storage, sensing, and brain-type information processing, requires the ability to control the properties of matter at the ultimate atomic scale. Here, a conceptually novel nanoarchitectonic strategy is proposed for controlling the number of dopant atoms in a solid electrolyte to obtain discrete electrical properties. Using α-Ag 2+ δ S nanodots with a finite number of nonstoichiometry excess dopants as a model system, a theory matched with experiments is presented that reveals the role of physical parameters, namely, the separation between electrochemical energy levels and the cohesive energy, underlying atomic-scale manipulation of dopants in nanodots. This strategy can be applied to different nanoscale materials as their properties strongly depend on the number of doping atoms/ions, and has the potential to create a new paradigm based on controlled single atom/ion transfer. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Plasmonic materials based on ZnO films and their potential for developing broadband middle-infrared absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Kesim, Yunus E., E-mail: yunus.kesim@bilkent.edu.tr; Battal, Enes [Department of Electrical and Electronics Engineering, Bilkent University, Ankara, 06800 (Turkey); UNAM-National Nanotechnology Research Center, Bilkent University, Ankara, 06800 (Turkey); Okyay, Ali K. [Department of Electrical and Electronics Engineering, Bilkent University, Ankara, 06800 (Turkey); UNAM-National Nanotechnology Research Center, Bilkent University, Ankara, 06800 (Turkey); Institute of Materials Science and Nanotechnology, Bilkent University, Ankara, 06800 (Turkey)

    2014-07-15

    Noble metals such as gold and silver have been extensively used for plasmonic applications due to their ability to support plasmons, yet they suffer from high intrinsic losses. Alternative plasmonic materials that offer low loss and tunability are desired for a new generation of efficient and agile devices. In this paper, atomic layer deposition (ALD) grown ZnO is investigated as a candidate material for plasmonic applications. Optical constants of ZnO are investigated along with figures of merit pertaining to plasmonic waveguides. We show that ZnO can alleviate the trade-off between propagation length and mode confinement width owing to tunable dielectric properties. In order to demonstrate plasmonic resonances, we simulate a grating structure and computationally demonstrate an ultra-wide-band (4–15 μm) infrared absorber.

  8. Accessing photon number via an atomic time interval

    International Nuclear Information System (INIS)

    Camparo, J.C.; Coffer, J.G.

    2002-01-01

    We show that Rabi resonances can be used to assess field strength in terms of time at the atomic level. Rabi resonances are enhancements in the amplitude of atomic population oscillations when the Rabi frequency, Ω, 'matches' a field-modulation frequency, ω m . We demonstrate that Ω=2κω m and find that κ=1.03±0.05. Since Ω is defined by field strength (i.e., photon number) through atomic constants, and ω m may be referenced to an atomic clock, our work shows that Rabi resonances provide a connection between time and photon number

  9. Atomic layer deposition of absorbing thin films on nanostructured electrodes for short-wavelength infrared photosensing

    International Nuclear Information System (INIS)

    Xu, Jixian; Sutherland, Brandon R.; Hoogland, Sjoerd; Fan, Fengjia; Sargent, Edward H.; Kinge, Sachin

    2015-01-01

    Atomic layer deposition (ALD), prized for its high-quality thin-film formation in the absence of high temperature or high vacuum, has become an industry standard for the large-area deposition of a wide array of oxide materials. Recently, it has shown promise in the formation of nanocrystalline sulfide films. Here, we demonstrate the viability of ALD lead sulfide for photodetection. Leveraging the conformal capabilities of ALD, we enhance the absorption without compromising the extraction efficiency in the absorbing layer by utilizing a ZnO nanowire electrode. The nanowires are first coated with a thin shunt-preventing TiO 2 layer, followed by an infrared-active ALD PbS layer for photosensing. The ALD PbS photodetector exhibits a peak responsivity of 10 −2  A W −1 and a shot-derived specific detectivity of 3 × 10 9  Jones at 1530 nm wavelength

  10. A Field Performance Evaluation Scheme for Microwave-Absorbing Material Coatings

    Directory of Open Access Journals (Sweden)

    Shaopeng Guan

    2017-03-01

    Full Text Available Performance evaluation is an important aspect in the study of microwave-absorbing material coatings. The reflectivity of the incident wave is usually taken as the performance indicator. There have been various methods to directly or indirectly measure the reflectivity, but existing methods are mostly cumbersome and require a strict testing environment. What is more, they cannot be applied to field measurement. In this paper, we propose a scheme to achieve field performance evaluation of microwave-absorbing materials, which adopts a small H-plane sectoral horn antenna as the testing probe and a small microwave reflectometer as the indicator. When the size of the H-plane sectoral horn antenna is specially designed, the field distribution at the antenna aperture can be approximated as a plane wave similar to the far field of the microwave emitted by a radar unit. Therefore, the reflectivity can be obtained by a near-field measurement. We conducted experiments on a kind of ferrite-based microwave-absorbing material at X band (8.2–12.4 GHz to validate the scheme. The experimental results show that the reflectivity is in agreement with the reference data measured by the conventional method as a whole.

  11. Low atomic number coating for XEUS silicon pore optics

    Science.gov (United States)

    Lumb, D. H.; Jensen, C. P.; Krumrey, M.; Cibik, L.; Christensen, F.; Collon, M.; Bavdaz, M.

    2008-07-01

    We describe a set of measurements on coated silicon substrates that are representative of the material to be used for the XEUS High Performance Pore Optics (HPO) technology. X-ray angular reflectance measurements at 2.8 and 8 keV, and energy scans of reflectance at a fixed angle representative of XEUS graze angles are presented. Reflectance is significantly enhanced for low energies when a low atomic number over-coating is applied. Modeling of the layer thicknesses and roughness is used to investigate the dependence on the layer thicknesses, metal and over coat material choices. We compare the low energy effective area increase that could be achieved with an optimized coating design.

  12. Dielectric microwave absorbing material processed by impregnation of carbon fiber fabric with polyaniline

    Directory of Open Access Journals (Sweden)

    Luiza de Castro Folgueras

    2007-03-01

    Full Text Available It is a known fact that the adequate combination of components and experimental conditions may produce materials with specific requirements. This study presents the effect of carbon fiber fabric impregnation with polyaniline conducting polymer aiming at the radar absorbing material processing. The experiments consider the sample preparation with one and two impregnations. The prepared samples were evaluated by reflectivity measurements, in the frequency range of 8-12 GHz and scanning electron microscopy analyses. The correlation of the results shows that the quantity of impregnated material influences the performance of the processed microwave absorber. This study shows that the proposed experimental route provides flexible absorbers with absorption values of the incident radiation close to 87%.

  13. The effective atomic number revisited in the light of modern photon-interaction cross-section databases

    DEFF Research Database (Denmark)

    Manohara, S.R.; Hanagodimath, S.M.; Thind, K. S.

    2010-01-01

    The effective atomic number, Z(eff), has been calculated for fatty acids and cysteine. It is shown that Z(eff) is a useful parameter for low-Z materials at any energy above 1 key. Absorption edges of medium-Z elements may complicate the energy dependence of Z(eff) below 10 key. The notion of Z......(eff) is perhaps most useful at energies where Compton scattering is dominating, and where Z(eff) is equal to the mean atomic number, , over a wide energy range around 1 MeV....

  14. Photon mass attenuation coefficients, effective atomic numbers and ...

    Indian Academy of Sciences (India)

    of atomic number Z was performed using the logarithmic regression analysis of the data measured by the authors and reported earlier. The best-fit coefficients so obtained in the photon ..... This photon build-up is a function of thickness and atomic number of the sample and also the incident photon energy, which combine to ...

  15. Characterization of shock-absorbing material for packages

    International Nuclear Information System (INIS)

    Mourao, Rogerio Pimenta

    2007-01-01

    Since 2001 Brazil has been participating in a regional effort with other Latin American countries which operate research reactors to improve its capability in the management of spent fuel elements from these reactors. One of the options considered is the long-term dry storage of the spent fuel in a dual purpose cask, i.e., a package for the transport and storage of radioactive material. In the scope of an IAEA-sponsored project, a cask was designed and a half-scale model for test was built. The cask consists of a sturdy cylindrical body provided with internal cavity to accommodate a basket holding the spent fuel elements, a double lid system, and external impact limiters. The cask is provided with top and bottom impact limiters, which are structures made of an external stainless steel skin and an energy-absorbing filling material. The filling material chosen was the wood composite denominated Oriented Strand Board (OSB), which is an engineered, mat-formed panel product made of strands, flakes or wafers sliced from small diameter, round wood logs and bonded with a binder under heat and pressure. The characterization of this material was carried in the scope of the cask project at the CDTN's laboratories. The tests conducted were the quasi-static compression, impact, shear-bending and edgewise shear tests. The compression, shear-bending and edgewise shear tests were carried out in a standard compression test machine and the impact test at a drop test tower equipped with a sturdy base and a drop weight. The main parameters of the material, like the Young and shear moduli, as well as the static and dynamic stress-strain curves and the specific energy absorbed, were determined during the test campaign. (author)

  16. Characterization of shock-absorbing material for packages

    Energy Technology Data Exchange (ETDEWEB)

    Mourao, Rogerio Pimenta [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)]. E-mail: mouraor@cdtn.br

    2007-07-01

    Since 2001 Brazil has been participating in a regional effort with other Latin American countries which operate research reactors to improve its capability in the management of spent fuel elements from these reactors. One of the options considered is the long-term dry storage of the spent fuel in a dual purpose cask, i.e., a package for the transport and storage of radioactive material. In the scope of an IAEA-sponsored project, a cask was designed and a half-scale model for test was built. The cask consists of a sturdy cylindrical body provided with internal cavity to accommodate a basket holding the spent fuel elements, a double lid system, and external impact limiters. The cask is provided with top and bottom impact limiters, which are structures made of an external stainless steel skin and an energy-absorbing filling material. The filling material chosen was the wood composite denominated Oriented Strand Board (OSB), which is an engineered, mat-formed panel product made of strands, flakes or wafers sliced from small diameter, round wood logs and bonded with a binder under heat and pressure. The characterization of this material was carried in the scope of the cask project at the CDTN's laboratories. The tests conducted were the quasi-static compression, impact, shear-bending and edgewise shear tests. The compression, shear-bending and edgewise shear tests were carried out in a standard compression test machine and the impact test at a drop test tower equipped with a sturdy base and a drop weight. The main parameters of the material, like the Young and shear moduli, as well as the static and dynamic stress-strain curves and the specific energy absorbed, were determined during the test campaign. (author)

  17. An x ray scatter approach for non-destructive chemical analysis of low atomic numbered elements

    Science.gov (United States)

    Ross, H. Richard

    1993-01-01

    A non-destructive x-ray scatter (XRS) approach has been developed, along with a rapid atomic scatter algorithm for the detection and analysis of low atomic-numbered elements in solids, powders, and liquids. The present method of energy dispersive x-ray fluorescence spectroscopy (EDXRF) makes the analysis of light elements (i.e., less than sodium; less than 11) extremely difficult. Detection and measurement become progressively worse as atomic numbers become smaller, due to a competing process called 'Auger Emission', which reduces fluorescent intensity, coupled with the high mass absorption coefficients exhibited by low energy x-rays, the detection and determination of low atomic-numbered elements by x-ray spectrometry is limited. However, an indirect approach based on the intensity ratio of Compton and Rayleigh scattered has been used to define light element components in alloys, plastics and other materials. This XRS technique provides qualitative and quantitative information about the overall constituents of a variety of samples.

  18. Atomic layer deposition of absorbing thin films on nanostructured electrodes for short-wavelength infrared photosensing

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Jixian; Sutherland, Brandon R.; Hoogland, Sjoerd; Fan, Fengjia; Sargent, Edward H., E-mail: ted.sargent@utoronto.ca [Department of Electrical and Computer Engineering, University of Toronto, 10 King' s College Road, Toronto, Ontario M5S 3G4 (Canada); Kinge, Sachin [Advanced Technology, Materials and Research, Research and Development, Hoge Wei 33- Toyota Technical Centre, B-1930 Zaventem (Belgium)

    2015-10-12

    Atomic layer deposition (ALD), prized for its high-quality thin-film formation in the absence of high temperature or high vacuum, has become an industry standard for the large-area deposition of a wide array of oxide materials. Recently, it has shown promise in the formation of nanocrystalline sulfide films. Here, we demonstrate the viability of ALD lead sulfide for photodetection. Leveraging the conformal capabilities of ALD, we enhance the absorption without compromising the extraction efficiency in the absorbing layer by utilizing a ZnO nanowire electrode. The nanowires are first coated with a thin shunt-preventing TiO{sub 2} layer, followed by an infrared-active ALD PbS layer for photosensing. The ALD PbS photodetector exhibits a peak responsivity of 10{sup −2} A W{sup −1} and a shot-derived specific detectivity of 3 × 10{sup 9} Jones at 1530 nm wavelength.

  19. A reflective-backing-free metamaterial absorber with broadband response

    Directory of Open Access Journals (Sweden)

    Cuilian Xu

    2017-06-01

    Full Text Available In this paper, we propose a polarization-independent and broadband perfect infrared (IR metamaterial absorber (MA without reflective backing. The proposed absorber is a periodic meta-atom array consisting of metal-dielectric-multilayer truncated cones which can absorb 80% EM wave from 50.70 to 81.87THz, while transmit 80% EM wave from 0 to 37.71THz. With the decreasing of frequency, the transmissivity increases, which is close to 100% from 0 to 5THz. We can broaden the absorption bandwidth of the MA by cascading multi-layers truncated cones. Furthermore, the proposed IR MA promises to be one desirable stealth material for radar-IR compatibility.

  20. The effective atomic number revisited in the light of modern photon-interaction cross-section databases

    International Nuclear Information System (INIS)

    Manohara, S.R.; Hanagodimath, S.M.; Thind, K.S.; Gerward, L.

    2010-01-01

    The effective atomic number, Z eff , has been calculated for fatty acids and cysteine. It is shown that Z eff is a useful parameter for low-Z materials at any energy above 1 keV. Absorption edges of medium-Z elements may complicate the energy dependence of Z eff below 10 keV. The notion of Z eff is perhaps most useful at energies where Compton scattering is dominating, and where Z eff is equal to the mean atomic number, , over a wide energy range around 1 MeV.

  1. A versatile atomic number correction for electron-probe microanalysis

    International Nuclear Information System (INIS)

    Love, G.; Cox, M.G.; Scott, V.D.

    1978-01-01

    A new atomic number correction is proposed for quantitative electron-probe microanalysis. Analytical expressions for the stopping power S and back-scatter R factors are derived which take into account atomic number of the target, incident electron energy and overvoltage; the latter expression is established using Monte Carlo calculations. The correct procedures for evaluating S and R for multi-element specimens are described. The new method, which overcomes some limitations inherent in earlier atomic number corrections, may readily be used where specimens are inclined to the electron beam. (author)

  2. Super water-absorbing new material from chitosan, EDTA and urea.

    Science.gov (United States)

    Narayanan, Abathodharanan; Dhamodharan, Raghavachari

    2015-12-10

    A new, super water-absorbing, material is synthesized by the reaction between chitosan, EDTA and urea and named as CHEDUR. CHEDUR is probably formed through the crosslinking of chitosan molecules (CH) with the EDTA-urea (EDUR) adduct that is formed during the reaction. CHEDUR as well as the other products formed in control reactions are characterized extensively. CHEDUR exhibits a very high water uptake capacity when compared with chitosan, chitosan-EDTA adduct, as well as a commercial diaper material. A systematic study was done to find the optimum composition as well as reaction conditions for maximum water absorbing capacity. CHEDUR can play a vital role in applications that demand the rapid absorption and slow release of water such as agriculture, as a three in one new material for the slow release of urea, water and other metal ions that can be attached through the EDTA component. The other potential advantage of CHEDUR is that it can be expected to degrade in soil based on its chitosan backbone. The new material with rapid and high water uptake could also find potential applications as biodegradable active ingredient of the diaper material. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Drop Weight Device Fabrication and Tests for a Dynamic Material Property of Shock-Absorbing Material and Structure in Transportation Package

    International Nuclear Information System (INIS)

    Choi, Woo Seok; Jeon, Jea Eon; Han, Sang Hyeok; Lee, Sang Hoon; Seo, Ki Seok

    2009-01-01

    A radioactive material transportation package consists of canister and impact limiters. IAEA Safety Standard Series No. TS-R-1 recommends a drop test to evaluate the structural integrity of a transportation package under a hypothetical accident condition. The free drop test of a transportation package from 9 m height simulates one of accident conditions. The transportation package has a potential energy corresponding to 9 m drop height, and this energy changes to a kinetic energy when it impacts on the target. The energy is absorbed by a deformation of shock-absorbing material so that the minimum energy is transferred to canister. Accordingly, the shock-absorbing material is a very important part in transportation package design. Since the data for shock-absorbing material characteristics is acquired by a static test in general, it is quite different to that of dynamic characteristics. And the dynamic characteristics data is hardly found in literature. In this study, a drop weight facility was designed and fabricated which produces an impact speed like that of free drop of 9 m height. Several materials considered for an impact limiter and impact limiter structures were tested by a drop weight facility to acquire a dynamic material characteristics data

  4. Drop Weight Device Fabrication and Tests for a Dynamic Material Property of Shock-Absorbing Material and Structure in Transportation Package

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Woo Seok; Jeon, Jea Eon; Han, Sang Hyeok; Lee, Sang Hoon; Seo, Ki Seok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2009-05-15

    A radioactive material transportation package consists of canister and impact limiters. IAEA Safety Standard Series No. TS-R-1 recommends a drop test to evaluate the structural integrity of a transportation package under a hypothetical accident condition. The free drop test of a transportation package from 9 m height simulates one of accident conditions. The transportation package has a potential energy corresponding to 9 m drop height, and this energy changes to a kinetic energy when it impacts on the target. The energy is absorbed by a deformation of shock-absorbing material so that the minimum energy is transferred to canister. Accordingly, the shock-absorbing material is a very important part in transportation package design. Since the data for shock-absorbing material characteristics is acquired by a static test in general, it is quite different to that of dynamic characteristics. And the dynamic characteristics data is hardly found in literature. In this study, a drop weight facility was designed and fabricated which produces an impact speed like that of free drop of 9 m height. Several materials considered for an impact limiter and impact limiter structures were tested by a drop weight facility to acquire a dynamic material characteristics data.

  5. Food-processes wastewaters treatment using food solid-waste materials as adsorbents or absorbents

    Science.gov (United States)

    Rapti, Ilaira; Georgopoulos, Stavros; Antonopoulou, Maria; Konstantinou, Ioannis; Papadaki, Maria

    2016-04-01

    The wastewaters generated by olive-mills during the production of olive oil, wastewaters from a dairy and a cow-farm unit and wastewaters from a small food factory have been treated by means of selected materials, either by-products of the same units, or other solid waste, as absorbents or adsorbents in order to identify the capacity of those materials to remove organic load and toxicity from the aforementioned wastewaters. The potential of both the materials used as absorbents as well as the treated wastewaters to be further used either as fertilizers or for agricultural irrigation purposes are examined. Dry olive leaves, sheep wool, rice husks, etc. were used either in a fixed-bed or in a stirred batch arrangemen,t employing different initial concentrations of the aforementioned wastewaters. The efficiency of removal was assessed using scpectrophotometric methods and allium test phytotoxicity measurements. In this presentation the response of each material employed is shown as a function of absorbent/adsorbent quantity and kind, treatment time and wastewater kind and initial organic load. Preliminary results on the potential uses of the adsorbents/absorbents and the treated wastewaters are also shown. Keywords: Olive-mill wastewaters, dairy farm wastewaters, olive leaves, zeolite, sheep wool

  6. Neutronic analysis of absorbing materials for the control rod system in reactor ALLEGRO

    Energy Technology Data Exchange (ETDEWEB)

    Cajko, Frantisek; Secansky, Michal; Chrebet, Tomas; Zajac, Radoslav; Darilek, Petr [VUJE, a.s., Trnava (Slovakia)

    2016-09-15

    Experimental reactor ALLEGRO is a gas cooled fast reactor in the design stage. The current design of its reactivity control system is based on control rods filled with boron carbide as the absorber. Because of disadvantages connected to high boron enrichment a possibility of using other absorbent materials was explored to lower the boron enrichment and increase the worth of the control rods. The results of neutronic Monte-Carlo analyses in a computational supercell are presented in this paper. Three absorbent materials most suitable for a use in reactor ALLEGRO (B{sub 4}C, EuB{sub 6} and ReB{sub 2}) have been analysed also in a full core model. A possible benefit of a neutron trap concept is explored as well but materials with satisfactory neutronic properties proved to be not suitable for expected high temperatures in the reactor.

  7. Absorbed Energy in Ship Collisions and Grounding

    DEFF Research Database (Denmark)

    Pedersen, Preben Terndrup; Zhang, Shengming

    1998-01-01

    is that the absorbed energy does not depend on the arrangement of the structure, the material properties, and the damage mode.The purpose of the present paper is to establish a new simple relation between the absorbed energy and the destroyed material volume, which can be used as a design tool for analysis of ship...... collisions and grounding. The developed expressions reflect the structural arrangement, the material properties and different damage patterns.The present method is validated against a large number of existing experimental results and detailed numerical simulation results. Applications to full-sale ship...

  8. Utilizing strongly absorbing materials for low-loss surface-wave nonlinear optics

    Science.gov (United States)

    Grosse, Nicolai B.; Franz, Philipp; Heckmann, Jan; Pufahl, Karsten; Woggon, Ulrike

    2018-04-01

    Optical media endowed with large nonlinear susceptibilities are highly prized for their employment in frequency conversion and the generation of nonclassical states of light. Although the presence of an optical resonance can greatly increase the nonlinear response (e.g., in epsilon-near-zero materials), the non-negligible increase in linear absorption often precludes the application of such materials in nonlinear optics. Absorbing materials prepared as thin films, however, can support a low-loss surface wave: the long-range surface exciton polariton (LRSEP). Its propagation lifetime increases with greater intrinsic absorption and reduced film thickness, provided that the film is embedded in a transparent medium (symmetric cladding). We explore LRSEP propagation in a molybdenum film by way of a prism-coupling configuration. Our observations show that excitation of the LRSEP mode leads to a dramatic increase in the yield of second-harmonic generation. This implies that the LRSEP mode is an effective vehicle for utilizing the nonlinear response of absorbing materials.

  9. Preparation of steel slag porous sound-absorbing material using coal powder as pore former.

    Science.gov (United States)

    Sun, Peng; Guo, Zhancheng

    2015-10-01

    The aim of the study was to prepare a porous sound-absorbing material using steel slag and fly ash as the main raw material, with coal powder and sodium silicate used as a pore former and binder respectively. The influence of the experimental conditions such as the ratio of fly ash, sintering temperature, sintering time, and porosity regulation on the performance of the porous sound-absorbing material was investigated. The results showed that the specimens prepared by this method had high sound absorption performance and good mechanical properties, and the noise reduction coefficient and compressive strength could reach 0.50 and 6.5MPa, respectively. The compressive strength increased when the dosage of fly ash and sintering temperature were raised. The noise reduction coefficient decreased with increasing ratio of fly ash and reducing pore former, and first increased and then decreased with the increase of sintering temperature and time. The optimum preparation conditions for the porous sound-absorbing material were a proportion of fly ash of 50% (wt.%), percentage of coal powder of 30% (wt.%), sintering temperature of 1130°C, and sintering time of 6.0hr, which were determined by analyzing the properties of the sound-absorbing material. Copyright © 2015. Published by Elsevier B.V.

  10. Low Absorbance Measurements

    Science.gov (United States)

    Harris, T. D.; Williams, A. M.

    1983-10-01

    The application of low absorption measurements to dilute solute determination requires specific instrumental characteristics. The use of laser intracavity absorption and thermal lens calorimetry to measure concentration is shown. The specific operating parameters that determine sensitivity are delineated along with the limits different measurement strategies impose. Finally areas of improvement in components that would result in improve sensitivity, accuracy, and reliability are discussed. During the past decade, a large number of methods have been developed for measuring the light absorbed by transparent materials. These include measurements on gases, liquids, and solids. The activity has been prompted by a variety of applications and a similar variety of disciplines. In Table 1 some representative examples of these methods is shown along with their published detection limits.1 It is clear that extraordinarily small absorbances can be measured. Most of the methods can be conveniently divided into two groups. These groups are those that measure the transmission of the sample and those that measure the light absorbed by the sample. The light absorbed methods are calorimetric in character. The advantages and disadvantages of each method varies depending on the principal application for which they were developed. The most prevalent motivation has been to characterize the bulk optical properties of transparent materials. Two examples are the development of extremely transparent glasses for use as fiber optic materials and the development of substrates for high power laser operation.

  11. The effective atomic number for gamma ray interactions with heavy metal oxide glasses

    DEFF Research Database (Denmark)

    Manohara, S. R.; Hanagodimath, S.M.; Gerward, Leif

    2010-01-01

    The effective atomic number, Z(eff), and the effective electron density, N-el,N-eff, have been calculated at photon energies from 1 keV to 100 GeV for CaO-SrO-B2O3, ZnO-PbO-B2O3, and CdO-PbO-B2O3 glasses with potential applications as gamma ray shielding materials. Appreciable variations are noted...... glasses have gamma ray shielding properties comparable with standard shielding materials, such as concrete....

  12. Photoelectron antibunching and absorber theory

    International Nuclear Information System (INIS)

    Pegg, D.T.

    1980-01-01

    The recently detected photoelectron antibunching effect is considered to be evidence for the quantised electromagnetic field, i.e. for the existence of photons. Direct-action quantum absorber theory, on the other hand, has been developed on the basis that the quantised field is illusory, with quantisation being required only for atoms. In this paper it is shown that photoelectron antibunching is readily explicable in terms of absorber theory and in fact is directly attributable to the quantum nature of the emitting and detecting atoms alone. The physical nature of the reduction of the wavepacket associated with the detection process is briefly discussed in terms of absorber theory. (author)

  13. Determination numbers of ionized atoms from emission and absorption lines

    International Nuclear Information System (INIS)

    Alizadeh Azimi, A.; Shokouhi, N.

    2002-01-01

    Saha, M., (1920) estimated that salter chromosphere is not only due to radiation from neutral atoms, but from ionized atoms. The failure to observe these stellar lines in the laboratory was attributed to internal temperature and pressure about 10* E + 6 K 10* E-7 atm. In this research we found that emission lines of ionized atoms (like Cs) could be measured in laboratory condition, (about 10* E-3 atm and 2000 K) by using Graphite France Atomic Absorption with injection 124 u g C sel. We calculated the numbers of ionized atoms from Bottzman law. We also measured these numbers from area under the energy-time curve

  14. Sb2Te3 crystal a potential absorber material for broadband photodetector: A first-principles study

    Directory of Open Access Journals (Sweden)

    Abdullahi Lawal

    Full Text Available Antimony telluride (Sb2Te3, a layered semiconductor material, is considered a promising absorbing material for a high-performance optoelectronic device within broadband wavelengths because of remarkable features like strong optical absorbance and the narrow direct band gap. In this work, based on the first-principles approach, we investigate in detail the structural, electronic and optical properties of the hexagonal Sb2Te3 compound. The structural and electronic properties were computed using the first-principles approach, treating exchange–correlation potential with generalized gradient approximation (GGA within density functional theory (DFT. Furthermore, for accurate prediction of the band gap, we go beyond DFT and calculated band structure using GW correction. The optical properties, namely, imaginary and real parts of complex dielectric function, absorption coefficient, refractive index, reflectivity, extinction coefficient, electron energy loss function and optical conductivity are performed by quasi-particle many-body perturbation theory (MBPT via Bethe-Salpeter equation (BSE. The computed structural parameters are in good agreement with available experimental data. The obtained quasi-particle (GW correction band structure show the semiconducting character of Sb2Te3 material with a direct band gap Eg of 0.221 eV, in agreement with previously reported value (Eg = 0.210 eV while the projected density of states indicates (PDOS that the p-orbital of Sb and Te atoms are responsible for material properties near the Fermi level. To our knowledge, our first reported calculations of optical properties, with the inclusion of electron-hole effects are consistent with available experimental measurements. Consistencies of our findings with experimental data validate the effectiveness of electron-hole interaction for theoretical investigation of optical properties. Keywords: DFT, Quasi-particle many-body perturbation theory, Bethe

  15. Corrosion resistant neutron absorbing coatings

    Science.gov (United States)

    Choi, Jor-Shan [El Cerrito, CA; Farmer, Joseph C [Tracy, CA; Lee, Chuck K [Hayward, CA; Walker, Jeffrey [Gaithersburg, MD; Russell, Paige [Las Vegas, NV; Kirkwood, Jon [Saint Leonard, MD; Yang, Nancy [Lafayette, CA; Champagne, Victor [Oxford, PA

    2012-05-29

    A method of forming a corrosion resistant neutron absorbing coating comprising the steps of spray or deposition or sputtering or welding processing to form a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material. Also a corrosion resistant neutron absorbing coating comprising a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material.

  16. Investigation of systematic errors of metastable "atomic pair" number

    CERN Document Server

    Yazkov, V

    2015-01-01

    Sources of systematic errors in analysis of data, collected in 2012, are analysed. Esti- mations of systematic errors in a number of “atomic pairs” fr om metastable π + π − atoms are presented.

  17. Effective atomic numbers for photon energy absorption of essential amino acids in the energy range 1 keV to 20 MeV

    International Nuclear Information System (INIS)

    Manohara, S.R.; Hanagodimath, S.M.

    2007-01-01

    Effective atomic numbers for photon energy-absorption (Z PEAeff ) of essential amino acids histidine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine have been calculated by a direct method in the energy region of 1 keV to 20 MeV. The Z PEAeff values have been found to change with energy and composition of the amino acids. The variations of mass energy-absorption coefficient, effective atomic number for photon interaction (Z PIeff ) and Z PEAeff with energy are shown graphically. Significant differences exist between Z PIeff and the Z PEAeff in the energy region of 8-100 keV for histidine and threonine; 6-100 keV for leucine, lysine, tryptophan, phenylalanine and valine; 15-400 keV for methionine. The effect of absorption edge on effective atomic numbers and the possibility of defining two set values of these parameters at the K-absorption edge of high-Z element present in the amino acids are discussed. The reasons for using Z PEAeff rather than the commonly used Z PIeff in medical radiation dosimetry for the calculation of absorbed dose in radiation therapy are also discussed

  18. Electron density and effective atomic number (Zeff) determination through x-ray Moiré deflectometry

    Science.gov (United States)

    Valdivia Leiva, Maria Pia; Stutman, Dan; Finkenthal, Michael

    2014-10-01

    Talbot-Lau based Moiré deflectometry is a powerful density diagnostic capable of delivering refraction information and attenuation from a single image, through the accurate detection of X-ray phase-shift and intensity. The technique is able to accurately measure both the real part of the index of refraction δ (directly related to electron density) and the attenuation coefficient μ of an object placed in the x-ray beam. Since the atomic number Z (or Zeff for a composite sample) is proportional to these quantities, an elemental map of the effective atomic number can be obtained with the ratio of the phase and the absorption image. The determination of Zeff from refraction and attenuation measurements with Moiré deflectometry could be of high interest in various fields of HED research such as shocked materials and ICF experiments as Zeff is linked, by definition, to the x-ray absorption properties of a specific material. This work is supported by U.S. DoE/NNSA Grant No. 435 DENA0001835.

  19. Fractal Model for Acoustic Absorbing of Porous Fibrous Metal Materials

    Directory of Open Access Journals (Sweden)

    Weihua Chen

    2016-01-01

    Full Text Available To investigate the changing rules between sound absorbing performance and geometrical parameters of porous fibrous metal materials (PFMMs, this paper presents a fractal acoustic model by incorporating the static flow resistivity based on Biot-Allard model. Static flow resistivity is essential for an accurate assessment of the acoustic performance of the PFMM. However, it is quite difficult to evaluate the static flow resistivity from the microstructure of the PFMM because of a large number of disordered pores. In order to overcome this difficulty, we firstly established a static flow resistivity formula for the PFMM based on fractal theory. Secondly, a fractal acoustic model was derived on the basis of the static flow resistivity formula. The sound absorption coefficients calculated by the presented acoustic model were validated by the values of Biot-Allard model and experimental data. Finally, the variation of the surface acoustic impedance, the complex wave number, and the sound absorption coefficient with the fractal dimensions were discussed. The research results can reveal the relationship between sound absorption and geometrical parameters and provide a basis for improving the sound absorption capability of the PFMMs.

  20. Stabilization of atoms with nonzero magnetic quantum numbers

    International Nuclear Information System (INIS)

    Sundaram, B.; Jensen, R.V.

    1993-01-01

    A classical analysis of the interaction of an atomic electron with an oscillating electric field with arbitrary initial quantum number, n, magnetic quantum number, m > 0, field strength, and frequency shows that the classical, dynamics for the perturbed electron can be stabilized for large fields and high frequencies. Using a four-dimensional map approximation to the classical dynamics, explicit expressions are obtained for the full parameter dependence of the boundaries of stability surrounding the open-quotes death valleyclose quotes of rapid classical ionization. A preliminary analysis of the quantum dynamics in terms of the quasienergy states associated with the corresponding quantum map is also included with particular emphasis on the role of unstable classical structures in stabilizing atoms. Together, these results provide motivation and direction for further theoretical and experimental studies of stabilization of atoms (and molecules) in super-intense microwave and laser fields

  1. Number-unconstrained quantum sensing

    Science.gov (United States)

    Mitchell, Morgan W.

    2017-12-01

    Quantum sensing is commonly described as a constrained optimization problem: maximize the information gained about an unknown quantity using a limited number of particles. Important sensors including gravitational wave interferometers and some atomic sensors do not appear to fit this description, because there is no external constraint on particle number. Here, we develop the theory of particle-number-unconstrained quantum sensing, and describe how optimal particle numbers emerge from the competition of particle-environment and particle-particle interactions. We apply the theory to optical probing of an atomic medium modeled as a resonant, saturable absorber, and observe the emergence of well-defined finite optima without external constraints. The results contradict some expectations from number-constrained quantum sensing and show that probing with squeezed beams can give a large sensitivity advantage over classical strategies when each is optimized for particle number.

  2. The effective atomic numbers of some biomolecules calculated by two methods: A comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Manohara, S. R.; Hanagodimath, S. M.; Gerward, L. [Department of Physics, Gulbarga University, Gulbarga, Karnataka 585 106 (India); Department of Physics, Technical University of Denmark, Lyngby DK-2800 (Denmark)

    2009-01-15

    The effective atomic numbers Z{sub eff} of some fatty acids and amino acids have been calculated by two numerical methods, a direct method and an interpolation method, in the energy range of 1 keV-20 MeV. The notion of Z{sub eff} is given a new meaning by using a modern database of photon interaction cross sections (WinXCom). The results of the two methods are compared and discussed. It is shown that for all biomolecules the direct method gives larger values of Z{sub eff} than the interpolation method, in particular at low energies (1-100 keV) At medium energies (0.1-5 MeV), Z{sub eff} for both methods is about constant and equal to the mean atomic number of the material. Wherever possible, the calculated values of Z{sub eff} are compared with experimental data.

  3. The effective atomic numbers of some biomolecules calculated by two methods: A comparative study

    International Nuclear Information System (INIS)

    Manohara, S. R.; Hanagodimath, S. M.; Gerward, L.

    2009-01-01

    The effective atomic numbers Z eff of some fatty acids and amino acids have been calculated by two numerical methods, a direct method and an interpolation method, in the energy range of 1 keV-20 MeV. The notion of Z eff is given a new meaning by using a modern database of photon interaction cross sections (WinXCom). The results of the two methods are compared and discussed. It is shown that for all biomolecules the direct method gives larger values of Z eff than the interpolation method, in particular at low energies (1-100 keV) At medium energies (0.1-5 MeV), Z eff for both methods is about constant and equal to the mean atomic number of the material. Wherever possible, the calculated values of Z eff are compared with experimental data.

  4. Heterogeneous neutron absorbers development

    International Nuclear Information System (INIS)

    Boccaccini, Aldo; Agueda, Horacio; Russo, Diego; Perez, Edmundo

    1987-01-01

    The use of solid burnable absorber materials in power light water reactors has increased in the last years, specially due to improvements attained in costs of generated electricity. The present work summarizes the basic studies made on an alumina-gadolinia system, where alumina is the inert matrix and gadolinia acts as burnable poison, and describes the fabrication method of pellets with that material. High density compacts were obtained in the range of concentrations used by cold pressing and sintering at 1600 deg C in inert (Ar) atmosphere. Finally, the results of the irradiation experiences made at RA-6 reactor, located at the Bariloche Atomic Center, are given where variations on negative reactivity caused by introduction of burnable poison rods were measured. The results obtained from these experiences are in good agreement with those coming from calculation codes. (Author)

  5. Dependences of the van der Waals atom-wall interaction on atomic and material properties

    International Nuclear Information System (INIS)

    Caride, A.O.; Klimchitskaya, G.L.; Mostepanenko, V.M.; Zanette, S.I.

    2005-01-01

    The 1%-accurate calculations of the van der Waals interaction between an atom and a cavity wall are performed in the separation region from 3 nm to 150 nm. The cases of metastable He * and Na atoms near metal, semiconductor, and dielectric walls are considered. Different approximations to the description of wall material and atomic dynamic polarizability are carefully compared. The smooth transition to the Casimir-Polder interaction is verified. It is shown that to obtain accurate results for the atom-wall van der Waals interaction at short separations with an error less than 1% one should use the complete optical-tabulated data for the complex refractive index of the wall material and the accurate dynamic polarizability of an atom. The obtained results may be useful for the theoretical interpretation of recent experiments on quantum reflection and Bose-Einstein condensation of ultracold atoms on or near surfaces of different kinds

  6. Broadband transmission noise reduction of smart panels featuring piezoelectric shunt circuits and sound-absorbing material.

    Science.gov (United States)

    Kim, Jaehwan; Lee, Joong-Kuen

    2002-09-01

    The possibility of a broadband noise reduction of piezoelectric smart panels is experimentally studied. A piezoelectric smart panel is basically a plate structure on which piezoelectric patches with electrical shunt circuits are mounted and sound-absorbing material is bonded on the surface of the structure. Sound-absorbing material can absorb the sound transmitted at the midfrequency region effectively while the use of piezoelectric shunt damping can reduce the transmission at resonance frequencies of the panel structure. To be able to reduce the sound transmission at low panel resonance frequencies, piezoelectric damping using the measured electrical impedance model is adopted. A resonant shunt circuit for piezoelectric shunt damping is composed of resistor and inductor in series, and they are determined by maximizing the dissipated energy through the circuit. The transmitted noise-reduction performance of smart panels is tested in an acoustic tunnel. The tunnel is a square cross-sectional tube and a loudspeaker is mounted at one side of the tube as a sound source. Panels are mounted in the middle of the tunnel and the transmitted sound pressure across panels is measured. When an absorbing material is bonded on a single plate, a remarkable transmitted noise reduction in the midfrequency region is observed except for the fundamental resonance frequency of the plate. By enabling the piezoelectric shunt damping, noise reduction is achieved at the resonance frequency as well. Piezoelectric smart panels incorporating passive absorbing material and piezoelectric shunt damping is a promising technology for noise reduction over a broadband of frequencies.

  7. The Atomic Number Revolution in Chemistry: A Kuhnian Analysis

    DEFF Research Database (Denmark)

    Wray, K. Brad

    2018-01-01

    This paper argues that the field of chemistry underwent a significant change of theory in the early twentieth century, when atomic number replaced atomic weight as the principle for ordering and identifying the chemical elements. It is a classic case of a Kuhnian revolution. In the process of add...

  8. Effective atomic numbers (Z_e_f_f) of based calcium phosphate biomaterials: a comparative study

    International Nuclear Information System (INIS)

    Fernandes Zenobio, Madelon Aparecida; Gonçalves Zenobio, Elton; Silva, Teógenes Augusto da; Socorro Nogueira, Maria do

    2016-01-01

    This study determined the interaction of radiation parameters of four biomaterials as attenuators to measure the transmitted X-rays spectra, the mass attenuation coefficient and the effective atomic number by spectrometric system comprising the CdTe detector. The biomaterial BioOss"® presented smaller mean energy than the other biomaterials. The μ/ρ and Z_e_f_f of the biomaterials showed their dependence on photon energy. The data obtained from analytical methods of x-ray spectra, µ/ρ and Z_e_f_f_, using biomaterials as attenuators, demonstrated that these materials could be used as substitutes for dentin, enamel and bone. Further, they are determinants for the characterization of the radiation in tissues or equivalent materials. - Highlights: • Measure of the transmitted x-rays spectra using based calcium phosphate biomaterials as attenuators. • Determination effective atomic number using four dental biomaterials. • Determination of the mass attenuation coefficient (µ/ρ) of the biomaterials samples calculated by the WinXCOM software. • Determination of the chemical composition of calcium phosphate biomaterials.

  9. Structural investigation and microwave characteristics of (Ba{sub 0.2}La{sub 0.8})Fe{sub 0.2}Mn{sub 0.4}Ti{sub 0.4}O{sub 3} absorbing materials

    Energy Technology Data Exchange (ETDEWEB)

    Manaf, Azwar [Dept. of Physics, Faculty of Mathematics and Natural Sciences, Indonesia of University (Indonesia); Adi, Wisnu Ari, E-mail: dwisnuaa@batan.go.id [Center for Technology of Nuclear Industry Material, National Nuclear Energy Agency (Indonesia)

    2014-03-24

    Synthesis and characterization of (Ba{sub 0.2}La{sub 0.8})Fe{sub 0.2}Mn{sub 0.4}Ti{sub 0.4}O{sub 3} absorbing material by mechanical alloying process has been performed. The absorbing material was prepared by oxide materials, namely BaCO{sub 3}, La{sub 2}O{sub 3}, TiO{sub 2}, Fe{sub 2}O{sub 3}, and MnCO{sub 3}. The mixture was milled for 10 h and then sintered at a temperature of 1000 ° C for 10 h. The refinement results of x-ray diffraction pattern of lanthanum manganite substituted with barium showed that the sample consisted of two phases, namely, La{sub 0.9125}MnO{sub 3} phase which has a structure monoclinic (I12/a1) with lattice parameters a = 5.527(1) Å, b = 5.572(1) Å and c = 7.810(1) Å, α = γ = 90° and β = 89.88(5)°, the unit cell volume of V = 240.57(8) Å{sup 3}, and the atomic density of ρ = 6.238 gr.cm{sup −3}. The microstructure analyses showed that the particle shapes was polygonal with the varied particle sizes of 1 ∼ 3 μm distributed homogeneously on the surface of the samples. The results of the electromagnetic wave absorption curve analysis by using a vector network analyzer (VNA) showed that the sample can absorb microwaves in the frequency range of 8-15 GHz with a very wide absorption bandwidth. It indicates that the as prepared absorber presents potential absorbing property in X and Ku-band. We concluded that the (Ba{sub 0.2}La{sub 0.8})Fe{sub 0.2}Mn{sub 0.4}Ti{sub 0.4}O{sub 3} material can be applied as a candidate absorber material of microwaves or electromagnetic wave.

  10. Two-Dimensional SnO Anodes with a Tunable Number of Atomic Layers for Sodium Ion Batteries

    KAUST Repository

    Zhang, Fan

    2017-01-18

    We have systematically changed the number of atomic layers stacked in 2D SnO nanosheet anodes and studied their sodium ion battery (SIB) performance. The results indicate that as the number of atomic SnO layers in a sheet decreases, both the capacity and cycling stability of the Na ion battery improve. The thinnest SnO nanosheet anodes (two to six SnO monolayers) exhibited the best performance. Specifically, an initial discharge and charge capacity of 1072 and 848 mAh g-1 were observed, respectively, at 0.1 A g-1. In addition, an impressive reversible capacity of 665 mAh g-1 after 100 cycles at 0.1 A g-1 and 452 mAh g-1 after 1000 cycles at a high current density of 1.0 A g-1 was observed, with excellent rate performance. As the average number of atomic layers in the anode sheets increased, the battery performance degraded significantly. For example, for the anode sheets with 10-20 atomic layers, only a reversible capacity of 389 mAh g-1 could be obtained after 100 cycles at 0.1 A g-1. Density functional theory calculations coupled with experimental results were used to elucidate the sodiation mechanism of the SnO nanosheets. This systematic study of monolayer-dependent physical and electrochemical properties of 2D anodes shows a promising pathway to engineering and mitigating volume changes in 2D anode materials for sodium ion batteries. It also demonstrates that ultrathin SnO nanosheets are promising SIB anode materials with high specific capacity, stable cyclability, and excellent rate performance.

  11. Effective atomic numbers of some tissue substitutes by different methods: A comparative study

    Directory of Open Access Journals (Sweden)

    Vishwanath P Singh

    2014-01-01

    Full Text Available Effective atomic numbers of some human organ tissue substitutes such as polyethylene terephthalate, red articulation wax, paraffin 1, paraffin 2, bolus, pitch, polyphenylene sulfide, polysulfone, polyvinylchloride, and modeling clay have been calculated by four different methods like Auto-Z eff, direct, interpolation, and power law. It was found that the effective atomic numbers computed by Auto-Z eff , direct and interpolation methods were in good agreement for intermediate energy region (0.1 MeV < E < 5 MeV where the Compton interaction dominates. A large difference in effective atomic numbers by direct method and Auto-Z eff was observed in photo-electric and pair-production regions. Effective atomic numbers computed by power law were found to be close to direct method in photo-electric absorption region. The Auto-Z eff , direct and interpolation methods were found to be in good agreement for computation of effective atomic numbers in intermediate energy region (100 keV < E < 10 MeV. The direct method was found to be appropriate method for computation of effective atomic numbers in photo-electric region (10 keV < E < 100 keV. The tissue equivalence of the tissue substitutes is possible to represent by any method for computation of effective atomic number mentioned in the present study. An accurate estimation of Rayleigh scattering is required to eliminate effect of molecular, chemical, or crystalline environment of the atom for estimation of gamma interaction parameters.

  12. Liver Regeneration After Portal Vein Embolization Using Absorbable and Permanent Embolization Materials in a Rabbit Model

    NARCIS (Netherlands)

    van den Esschert, Jacomina W.; van Lienden, Krijn P.; Alles, Lindy K.; van Wijk, Albert C.; Heger, Michal; Roelofs, Joris J.; van Gulik, Thomas M.

    2012-01-01

    Objective: To compare the safety and hypertrophy response after portal vein embolization (PVE) using 2 absorbable and 3 permanent embolization materials. Background: Portal vein embolization is used to increase future remnant liver volume preoperatively. Application of temporary, absorbable

  13. Shock absorber

    International Nuclear Information System (INIS)

    Housman, J.J.

    1978-01-01

    A shock absorber is described for use in a hostile environment at the end of a blind passage for absorbing impact loads. The shock absorber includes at least one element which occupies the passage and which is comprised of a porous brittle material which is substantially non-degradable in the hostile environment. A void volume is provided in the element to enable the element to absorb a predetermined level of energy upon being crushed due to impact loading

  14. Neutron absorbers and methods of forming at least a portion of a neutron absorber

    Energy Technology Data Exchange (ETDEWEB)

    Guillen, Donna P; Porter, Douglas L; Swank, W David; Erickson, Arnold W

    2014-12-02

    Methods of forming at least a portion of a neutron absorber include combining a first material and a second material to form a compound, reducing the compound into a plurality of particles, mixing the plurality of particles with a third material, and pressing the mixture of the plurality of particles and the third material. One or more components of neutron absorbers may be formed by such methods. Neutron absorbers may include a composite material including an intermetallic compound comprising hafnium aluminide and a matrix material comprising pure aluminum.

  15. Design of absorber assemblies with intentional pellet-cladding mechanical interaction

    International Nuclear Information System (INIS)

    Hollenberg, G.W.; Birney, K.R.; Pitner, A.L.; Basmajian, J.A.

    1980-04-01

    A number of improvements in absorber assembly performance characteristics can be achieved through implementation of absorber cladding mechanical interaction (ACMI). Benefits include lower operating temperatures, less potential for material relocation, longer lifetime, and increased reactivity worth. Analyses indicate that substantial cladding strains may be attainable without significant risk of breach. However, actual in-reactor testing of ACMI in absorber elements will be required before design criteria can be revised to accept ACMI

  16. Summary of the CERN Workshop on Materials for Collimators and Beam Absorbers

    CERN Document Server

    Schmidt, R; Bertarelli, A; Ferrari, A; Weterings, W; Mokhov, N V

    2008-01-01

    The main focus of the workshop was on collimators and beam absorbers for (mainly) High Energy Hadron Accelerators, with the energy stored in the beams far above damage limit. The objective was to better understand the technological limits imposed by mechanisms related to beam impact on materials. The idea to organise this workshop came up during the High Intensity High Brightness Hadron Beams, ICFA-HB2006 in Japan [1]. The workshop was organised 3-5 September 2007 at CERN, with about 60 participants, including 20 from outside CERN. About 30 presentations were given [2]. The event was driven by the LHC challenge, with more than 360 MJoule stored in each proton beam. The entire beam or its fraction will interact with LHC collimators and beam absorbers, and with the LHC beam dump blocks. Collimators and beam absorbers are also of the interest for other labs and accelerators: - CERN: for the CNGS target, for SPS beam absorbers (extraction protection) and collimators for protecting the transfer line between SPS an...

  17. Bismuth X-ray absorber studies for TES microcalorimeters

    International Nuclear Information System (INIS)

    Sadleir, J.E.; Bandler, S.R.; Brekosky, R.P.; Chervenak, J.; Figueroa-Feliciano, E.; Finkbeiner, F.; Iyomoto, N.; Kelley, R.L.; Kilbourne, C.A.; King, J.M.; Porter, F.S.; Robinson, I.K.; Saab, T.; Talley, D.J.

    2006-01-01

    Bismuth's large atomic number and low carrier density makes it an attractive X-ray absorber material for microcalorimeters. Bismuth's long Fermi wavelength and long mean free paths have motivated much interest in the fabrication of high quality bismuth films to study quantum size effects. Despite such incentives, fabrication of high quality bismuth films has proven difficult, and measured properties of such films are highly variable in the literature. Implementing a bismuth deposition process for TES (superconducting Transition Edge Sensor) device fabrication presents additional challenges particularly at interfaces due to the inherent granularity and surface roughness of its films, its low melting point, and its tendency to diffuse and form undesired intermetallic phases. We report observations of Bi-Cu and Bi-Au diffusion in our devices correlating with large shifts in T c (superconducting transition temperature). Using SEM and in situ R vs T annealing experiments we have been able to study these diffusion processes and identify their activation temperatures

  18. Filtration: Novel Absorber Evaluation Club aims at standardized testing

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    In the past few years a number of novel absorber materials, both organic and inorganic, have appeared on the market - some claiming to achieve very large decontamination factors for metal ions, including those having radioactive isotopes. Several of these materials have been tested by individual companies in the nuclear industry and some have shown promise as decontaminants for radioactive waste streams. Unfortunately, the results obtained for the treatment of a particular waste stream cannot be applied directly to the many and diverse waste streams generated throughout the nuclear industry. A unified and standardized testing programme making use of available expertise is necessary to provide a fair and meaningful comparison. In November 1988, representatives of the United Kingdom nuclear industry agreed to form the Novel Absorber Evaluation Club to assess absorber materials and to undertake the necessary work to identify the extent and rate of adsorption of radionuclides by such materials from a set of typical reference waste streams. (author)

  19. Producing of Impedance Tube for Measurement of Acoustic Absorption Coefficient of Some Sound Absorber Materials

    Directory of Open Access Journals (Sweden)

    R. Golmohammadi

    2008-04-01

    Full Text Available Introduction & Objective: Noise is one of the most important harmful agents in work environment. In spit of industrial improvements, exposure with over permissible limit of noise is counted as one of the health complication of workers. In Iran, do not exact information of the absorption coefficient of acoustic materials. Iranian manufacturer have not laboratory for measured of sound absorbance of their products, therefore using of sound absorber is limited for noise control in industrial and non industrial constructions. The goal of this study was to design an impedance tube based on pressure method for measurement of the sound absorption coefficient of acoustic materials.Materials & Methods: In this study designing of measuring system and method of calculation of sound absorption based on a available equipment and relatively easy for measurement of the sound absorption coefficient related to ISO10534-1 was performed. Measuring system consist of heavy asbestos tube, a pure tone sound generator, calibrated sound level meter for measuring of some commonly of sound absorber materials was used. Results: In this study sound absorption coefficient of 23 types of available acoustic material in Iran was tested. Reliability of results by three repeat of measurement was tested. Results showed that the standard deviation of sound absorption coefficient of study materials was smaller than .Conclusion: The present study performed a necessary technology of designing and producing of impedance tube for determining of acoustical materials absorption coefficient in Iran.

  20. Enhancing the Performance of the Microwave Absorbing Materials by Using Dielectric Resonator Arrays

    Directory of Open Access Journals (Sweden)

    Omar H. Al-Zoubi

    2017-01-01

    Full Text Available We present a technique for enhancing the performance of microwave absorbing materials in terms of weight, thickness, and bandwidth. The introduced technique is based on fabricating the microwave absorbing (MA material in a structure comprised of an array of circular cylinder dielectric resonators (CDR backed by a perfect electric conductor (PEC ground plane. Numerical electromagnetic methods are employed to study the properties of the proposed MA array structures, where 3D full wave simulation using finite-element method is implemented. The obtained results show that the performance of the MA-CDR arrays significantly outperforms that of a flat layer composed of the same material and having equivalent thickness. A flat layer of MA material with thickness of 5 mm backed by perfect electric conductor (PEC shows as low as -50 dB reflection loss (RL peak and ~3 GHz 10-dB bandwidth, whereas an MA-CDR array, composed of the same MA material, of height of 4 mm can achieve as low as ~−50 dB RL peak and ~12 GHz 10-dB RL bandwidth.

  1. Improved atom number with a dual color magneto—optical trap

    International Nuclear Information System (INIS)

    Cao Qiang; Luo Xin-Yu; Gao Kui-Yi; Wang Xiao-Rui; Wang Ru-Quan; Chen Dong-Min

    2012-01-01

    We demonstrate a novel dual color magneto—optical trap (MOT), which uses two sets of overlapping laser beams to cool and trap 87 Rb atoms. The volume of cold cloud in the dual color MOT is strongly dependent on the frequency difference of the laser beams and can be significantly larger than that in the normal MOT with single frequency MOT beams. Our experiment shows that the dual color MOT has the same loading rate as the normal MOT, but much longer loading time, leading to threefold increase in the number of trapped atoms. This indicates that the larger number is caused by reduced light induced loss. The dual color MOT is very useful in experiments where both high vacuum level and large atom number are required, such as single chamber quantum memory and Bose—Einstein condensation (BEC) experiments. Compared to the popular dark spontaneous-force optical trap (dark SPOT) technique, our approach is technically simpler and more suitable to low power laser systems. (rapid communication)

  2. Interfacial trapping mechanism of He in Cu–Nb multilayer materials

    Energy Technology Data Exchange (ETDEWEB)

    McPhie, M.G., E-mail: mathieu.mcphie@georgiatech-metz.fr [UMI 2958, Georgia Tech-CNRS, 2-3 rue Marconi, 57070 Metz (France); Capolungo, L. [UMI 2958, Georgia Tech-CNRS, 2-3 rue Marconi, 57070 Metz (France); G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0405 (United States); Dunn, A.Y. [UMI 2958, Georgia Tech-CNRS, 2-3 rue Marconi, 57070 Metz (France); Cherkaoui, M. [UMI 2958, Georgia Tech-CNRS, 2-3 rue Marconi, 57070 Metz (France); G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0405 (United States)

    2013-06-15

    He atom trapping in hetero-interphase materials is studied by atomistic simulations, focusing on the KS1 and KSmin interfaces in Cu–Nb. If the bulk crystalline materials are defect free, single He atoms eventually become absorbed into the interfacial region via one of two different processes. In the first process, all He atoms arriving at the interface from the Cu side of the interface and some He atoms arriving from the Nb side, are trapped via the formation of a helium-vacancy (HeV) cluster in the second or third interfacial planes of the copper crystal. The immobile HeV cluster is found to be stable against dissociation and recombination. In the second case the He atoms are absorbed as interstitial atoms in one of the terminal planes. This process is dependent on the interstitial content of the interface and is found to be weak in the case of the KS1 interface.

  3. Toward electron exit wave tomography of amorphous materials at atomic resolution

    Energy Technology Data Exchange (ETDEWEB)

    Borisenko, Konstantin B., E-mail: konstantin.borisenko@materials.ox.ac.uk [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Moldovan, Grigore [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Kirkland, Angus I., E-mail: angus.kirkland@materials.ox.ac.uk [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Van Dyck, Dirk [Department of Physics, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp (Belgium); Tang, Hsin-Yu; Chen, Fu-Rong [Department of Engineering and System Science, National Tsing Hua University, Kuang-Fu Road, 300 Hsinchu, Taiwan (China)

    2012-09-25

    Highlights: Black-Right-Pointing-Pointer We suggest a novel electron exit wave tomography approach to obtain three dimensional atomic structures of amorphous materials. Black-Right-Pointing-Pointer Theoretical tests using a model of amorphous Si doped with Au show that it is feasible to reconstruct both Si and Au atoms positions. Black-Right-Pointing-Pointer Reconstructions of the strongly scattering Au atoms positions appear to be insensitive to typical experimental errors. - Abstract: We suggest to use electron exit wave phase for tomographic reconstruction of structure of Au-doped amorphous Si with atomic resolution. In the present theoretical investigation into the approach it is found that the number of projections and the accuracy of defocus in the focal series restoration are the main factors that contribute to the final resolution. Although resolution is ultimately limited by these factors, phase shifts in the exit wave are sufficient to identify the position of Au atoms in an amorphous Si needle model, even when only 19 projections with defocus error of 4 nm are used. Electron beam damage will probably further limit the resolution of such tomographic reconstructions, however beam damage can be mitigated using lower accelerating voltages.

  4. Conceptual basis for calculations of absorbed-dose distributions

    International Nuclear Information System (INIS)

    Sinclair, W.K.; Rossi, H.H.; Alsmiller, R.G.; Berger, M.J.; Kellerer, A.M.; Roesch, W.C.; Spencer, L.V.; Zaider, M.A.

    1991-01-01

    The effects of radiation on matter are initiated by processes in which atoms and molecules of the medium are ionized or excited. Over a wide range of conditions, it is an excellent approximation to assume that the average number of ionizations and excitations is proportional to the amount of energy imparted to the medium by ionizing radiation in the volume of interest. The absorbed dose, that is, the average amount of energy imparted to the medium per unit mass, is therefore of central importance for the production of radiation effects, and the calculation of absorbed-dose distributions in irradiated media is the focus of interest of the present report. It should be pointed out, however, that even though absorbed dose is useful as an index relating absorbed energy to radiation effects, it is almost never sufficient; it may have to be supplemented by other information, such as the distributions of the amounts of energy imparted to small sites, the correlation of the amounts of energy imparted to adjacent sites, and so on. Such quantities are termed stochastic quantities. Unless otherwise stated, all quantities considered in this report are non-stochastic. 266 refs., 11 figs., 2 tabs

  5. Atom beams split by gentle persuasion

    International Nuclear Information System (INIS)

    Pool, R.

    1994-01-01

    Two different research teams have taken a big step toward atom interferometry. They have succeeded in splitting atomic beams by using atoms in spin states that neither absorb nor reemit laser light. By proper adjustment of experimental conditions, atoms are changed from one spin state to another, without passing through the intermediary excited state. The atoms in essence absorb momentum from the laser photons, without absorption or emission of photons. The change in momentum deflects atoms in the proper spin state

  6. The role of absorbent building materials in moderating changes of relative humidity

    DEFF Research Database (Denmark)

    Padfield, Tim

    The problem studied in this work is, how porous, absorbent materials surroundning or placed in a room influence the relative humidity of the room. This is of interest in designing precautions and machinery to monitor the indoor climate in museums and dwelling rooms. - A novel technique for the in...

  7. Big Atoms for Small Children: Building Atomic Models from Common Materials to Better Visualize and Conceptualize Atomic Structure

    Science.gov (United States)

    Cipolla, Laura; Ferrari, Lia A.

    2016-01-01

    A hands-on approach to introduce the chemical elements and the atomic structure to elementary/middle school students is described. The proposed classroom activity presents Bohr models of atoms using common and inexpensive materials, such as nested plastic balls, colored modeling clay, and small-sized pasta (or small plastic beads).

  8. Recycling ceramic industry wastes in sound absorbing materials

    Directory of Open Access Journals (Sweden)

    C. Arenas

    2016-10-01

    Full Text Available The scope of this investigation is to develop a material mainly composed (80% w/w of ceramic wastes that can be applied in the manufacture of road traffic noise reducing devices. The characterization of the product has been carried out attending to its acoustic, physical and mechanical properties, by measuring the sound absorption coefficient at normal incidence, the open void ratio, density and compressive strength. Since the sound absorbing behavior of a porous material is related to the size of the pores and the thickness of the specimen tested, the influence of the particle grain size of the ceramic waste and the thickness of the samples tested on the properties of the final product has been analyzed. The results obtained have been compared to a porous concrete made of crushed granite aggregate as a reference commercial material traditionally used in similar applications. Compositions with coarse particles showed greater sound absorption properties than compositions made with finer particles, besides presenting better sound absorption behavior than the reference porous concrete. Therefore, a ceramic waste-based porous concrete can be potentially recycled in the highway noise barriers field.

  9. Recent progress of atomic layer deposition on polymeric materials

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Hong Chen; Ye, Enyi [Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 2 Fusionopolis Way, Innovis, #08-03, Singapore 138634 (Singapore); Li, Zibiao, E-mail: lizb@imre.a-star.edu.sg [Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 2 Fusionopolis Way, Innovis, #08-03, Singapore 138634 (Singapore); Han, Ming-Yong [Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 2 Fusionopolis Way, Innovis, #08-03, Singapore 138634 (Singapore); Loh, Xian Jun, E-mail: lohxj@imre.a-star.edu.sg [Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 2 Fusionopolis Way, Innovis, #08-03, Singapore 138634 (Singapore); Department of Materials Science and Engineering, National University of Singapore, Singapore 117574 (Singapore); Singapore Eye Research Institute, 20 College Road, Singapore 169856 (Singapore)

    2017-01-01

    As a very promising surface coating technology, atomic layer deposition (ALD) can be used to modify the surfaces of polymeric materials for improving their functions and expanding their application areas. Polymeric materials vary in surface functional groups (number and type), surface morphology and internal structure, and thus ALD deposition conditions that typically work on a normal solid surface, usually do not work on a polymeric material surface. To date, a large variety of research has been carried out to investigate ALD deposition on various polymeric materials. This paper aims to provide an in-depth review of ALD deposition on polymeric materials and its applications. Through this review, we will provide a better understanding of surface chemistry and reaction mechanism for controlled surface modification of polymeric materials by ALD. The integrated knowledge can aid in devising an improved way in the reaction between reactant precursors and polymer functional groups/polymer backbones, which will in turn open new opportunities in processing ALD materials for better inorganic/organic film integration and potential applications. - Highlights: • ALD deposition on different natural and synthetic polymer materials • Reaction mechanism based on the surface functional groups of polymers • Application of ALD-modified polymers in different fields.

  10. Decontamination of skin exposed to nanocarriers using an absorbent textile material and PEG-12 dimethicone

    International Nuclear Information System (INIS)

    Lademann, J; Richter, H; Knorr, F; Baier, G; Landfester, K; Frazier, L; Gefeller, H; Wunderlich, U; Gross, I; Rühl, E

    2014-01-01

    The removal of noxious particulate contaminants such as pollutants derived from particle-to-gas conversions from exposed skin is essential to avoid the permeation of potentially harmful substances into deeper skin layers via the stratum corneum or the skin appendages and their dispersion throughout the circulatory system. This study is aimed at evaluating the efficacy of using the silicone glycol polymer PEG-12 dimethicone and an absorbent textile material to remove fluorescing hydroxyethyl starch nanocapsules implemented as model contaminants from exposed porcine ear skin. Using laser scanning microscopy, it could be shown that while the application and subsequent removal of the absorbent textile material alone did not result in sufficient decontamination, the combined application with PEG-12 dimethicone almost completely eliminated the nanocapsules from the surface of the skin. By acting as a wetting agent, PEG-12 dimethicone enabled the transfer of the nanocapsules into a liquid phase which was taken up by the absorbent textile material. Only traces of fluorescence remained detectable in several skin furrows and follicular orifices, suggesting that the repeated implementation of the procedure may be necessary to achieve total skin surface decontamination. (letter)

  11. Advances in low atomic number element analysis by wavelength dispersive x-ray fluorescence spectrometry

    International Nuclear Information System (INIS)

    Vrebos, B.

    1996-01-01

    Traditionally, the analysis of low atomic number has been a chal1enging task for wavelength dispersive x-ray fluorescence spectrometry. Among the most important factors influencing analysis of the low atomic number elements (from Z=11 downwards) are the fluorescence yield, absorption and the dispersion. The effect of each of these factors on the overall performance will be illustrated. The long wavelengths involved (longer than I nm) used to pose severe problems concerning the monochromator used. Early instruments relied on lead stearate or Blodgett Langmuir soap films for the diffraction of the characteristic radiation. Nowadays, synthetic multilayers are commonly used. The performance of these multilayers is determined by the reflectivity, the resolution and the absorption of the characteristic radiation to be diffracted. These parameters can be optimised by adequately selecting the composition of the materials involved. The sensitivity of the modem instruments is sufficient to allow quantitative analysis. However, this aspect of WDS XRF is still met with considerable scepticism. Examples of quantitative analysis will be given to illustrate the current capability

  12. Review of Mid- to High-Temperature Solar Selective Absorber Materials

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, C. E.

    2002-07-01

    This report describes the concentrating solar power (CSP) systems using solar absorbers to convert concentrated sunlight to thermal electric power. It is possible to achieve solar absorber surfaces for efficient photothermal conversion having high solar absorptance (a) for solar radiation and a low thermal emittance (e) at the operational temperature. A low reflectance (?'' 0) at wavelengths (?) 3 mm and a high reflectance (?'' 1) at l 3 mm characterize spectrally selective surfaces. The operational temperature ranges of these materials for solar applications can be categorized as low temperature (T< 100 C), mid-temperature (100 C< T< 400 C), and high-temperature (T> 400 C). High- and mid-temperature applications are needed for CSP applications. For CSP applications, the ideal spectrally selective surface would be low-cost and easy to manufacture, chemically and thermally stable in air at elevated operating temperatures (T= 500 C), and have a solar absorptance= 0.98 and a thermal emittance= 0.05 at 500 C.

  13. Dependence of the Casimir-Polder interaction between an atom and a cavity wall on atomic and material properties

    International Nuclear Information System (INIS)

    Mostepanenko, V M; Babb, J F; Caride, A O; Klimchitskaya, G L; Zanette, S I

    2006-01-01

    The Casimir-Polder and van der Waals interactions between an atom and a flat cavity wall are investigated under the influence of real conditions including the dynamic polarizability of the atom, actual conductivity of the wall material and nonzero temperature of the wall. The cases of different atoms near metal and dielectric walls are considered. It is shown that to obtain accurate results for the atom-wall interaction at short separations, one should use the complete tabulated optical data for the complex refractive index of the wall material and the accurate dynamic polarizability of an atom. At relatively large separations in the case of a metal wall, one may use the plasma model dielectric function to describe the dielectric properties of the wall material. The obtained results are important for the theoretical interpretation of experiments on quantum reflection and Bose-Einstein condensation

  14. Combustor exhaust-emissions and blowout-limits with diesel number 2 and Jet A fuels utilizing air-atomizing and pressure-atomizing nozzles

    Science.gov (United States)

    Ingebo, R. D.; Norgren, C. T.

    1975-01-01

    The effect of fuel properties on exhaust emissions and blowout limits of a high-pressure combustor segment is evaluated using a splash-groove air-atomizing fuel injector and a pressure-atomizing simplex fuel nozzle to burn both diesel number 2 and Jet A fuels. Exhaust emissions and blowout data are obtained and compared on the basis of the aromatic content and volatility of the two fuels. Exhaust smoke number and emission indices for oxides of nitrogen, carbon monoxide, and unburned hydrocarbons are determined for comparison. As compared to the pressure-atomizing nozzle, the air-atomizing nozzle is found to reduce nitrogen oxides by 20%, smoke number by 30%, carbon monoxide by 70%, and unburned hydrocarbons by 50% when used with diesel number 2 fuel. The higher concentration of aromatics and lower volatility of diesel number 2 fuel as compared to Jet A fuel appears to have the most detrimental effect on exhaust emissions. Smoke number and unburned hydrocarbons are twice as high with diesel number 2 as with Jet A fuel.

  15. Nanophase materials assembled from atomic clusters

    International Nuclear Information System (INIS)

    Siegel, R.W.

    1989-09-01

    The preparation of atomic clusters of metals and ceramics by means of the gas-condensation method, followed by their in situ consolidation under high-vacuum conditions, has recently led to the synthesis of a new class of ultrafine-grained materials for which their physics is intimately coupled with their application. These nanophase materials, with 2 to 20 nm grain sizes, appear to have properties that are often rather different from conventional materials, and also processing characteristics that are greatly improved. The nanophase synthesis method described here should enable the design of materials heretofore unavailable, with improved or unique properties, based upon an understanding of the physics of these new materials. 23 refs., 8 figs

  16. Nanophase materials assembled from atomic clusters

    Energy Technology Data Exchange (ETDEWEB)

    Siegel, R.W.

    1989-09-01

    The preparation of atomic clusters of metals and ceramics by means of the gas-condensation method, followed by their in situ consolidation under high-vacuum conditions, has recently led to the synthesis of a new class of ultrafine-grained materials for which their physics is intimately coupled with their application. These nanophase materials, with 2 to 20 nm grain sizes, appear to have properties that are often rather different from conventional materials, and also processing characteristics that are greatly improved. The nanophase synthesis method described here should enable the design of materials heretofore unavailable, with improved or unique properties, based upon an understanding of the physics of these new materials. 23 refs., 8 figs.

  17. Quantum phase crossovers with finite atom number in the Dicke model

    International Nuclear Information System (INIS)

    Hirsch, J G; Castaños, O; Nahmad-Achar, E; López-Peña, R

    2013-01-01

    Two-level atoms interacting with a one-mode cavity field at zero temperature have order parameters which reflect the presence of a quantum phase transition at a critical value of the atom–cavity coupling strength. Two popular examples are the number of photons inside the cavity and the number of excited atoms. Coherent states provide a mean field description, which becomes exact in the thermodynamic limit. Employing symmetry-adapted (SA) SU(2) coherent states the quantum crossover, precursor of the critical behavior, can be described for a finite number of atoms. A variation after projection treatment, involving a numerical minimization of the SA energy surface, associates the quantum crossover with a discontinuity in the order parameters, which originates from competition between two local minima in the SA energy surface. Although this discontinuity is not present in finite systems, it provides a good description of 1/N effects in the observables. (paper)

  18. Standard specification for boron-Based neutron absorbing material systems for use in nuclear spent fuel storage racks

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This specification defines criteria for boron-based neutron absorbing material systems used in racks in a pool environment for storage of nuclear light water reactor (LWR) spent-fuel assemblies or disassembled components to maintain sub-criticality in the storage rack system. 1.2 Boron-based neutron absorbing material systems normally consist of metallic boron or a chemical compound containing boron (for example, boron carbide, B4C) supported by a matrix of aluminum, steel, or other materials. 1.3 In a boron-based absorber, neutron absorption occurs primarily by the boron-10 isotope that is present in natural boron to the extent of 18.3 ± 0.2 % by weight (depending upon the geological origin of the boron). Boron, enriched in boron-10 could also be used. 1.4 The materials systems described herein shall be functional – that is always be capable to maintain a B10 areal density such that subcriticality Keff <0.95 or Keff <0.98 or Keff < 1.0 depending on the design specification for the service...

  19. The Potential of Coconut Shell Powder (CSP) and Coconut Shell Activated Carbon (CSAC) Composites as Electromagnetic Interference (EMI) Absorbing Material

    International Nuclear Information System (INIS)

    Siti Nurbazilah Abdul Jabal; Seok, Y.B.; Hoon, W.F.

    2016-01-01

    Agriculture waste is potentially useful as an alternative material to absorb and attenuate electromagnetic interference (EMI). This research highlights the use of coconut shell powder (CSP) and coconut shell activated carbon (CSAC) as raw materials with epoxy resin and amine hardener composite to absorb microwave signals over frequency of 1 - 8 GHz. In order to investigate the suitability of these raw materials as EMI absorbing material, carbon composition of the raw materials is determined through CHNS Elemental Analysis. The surface morphology of the raw materials in term of porosity is investigated by using TM3000 Scanning Electron Microscope (SEM). The complex permittivity of the composites is determined by using high temperature dielectric probe in conjunction with Network Analyzer. From the result, the Carbon% of CSP and CSAC is 46.70 % and 84.28 % respectively. In term of surface morphology, the surface porosity of CSP and CSAC is in the range of 2 μm and 1 μm respectively. For the dielectric properties, the dielectric constant and the dielectric loss factor for CSP and CSAC is 4.5767 and 64.8307 and 1.2144 and 13.8296 respectively. The materials more potentially useful as substitute materials for electromagnetic interference (EMI) absorbing are discussed. (author)

  20. Perovskite oxides for visible-light-absorbing ferroelectric and photovoltaic materials.

    Science.gov (United States)

    Grinberg, Ilya; West, D Vincent; Torres, Maria; Gou, Gaoyang; Stein, David M; Wu, Liyan; Chen, Guannan; Gallo, Eric M; Akbashev, Andrew R; Davies, Peter K; Spanier, Jonathan E; Rappe, Andrew M

    2013-11-28

    Ferroelectrics have recently attracted attention as a candidate class of materials for use in photovoltaic devices, and for the coupling of light absorption with other functional properties. In these materials, the strong inversion symmetry breaking that is due to spontaneous electric polarization promotes the desirable separation of photo-excited carriers and allows voltages higher than the bandgap, which may enable efficiencies beyond the maximum possible in a conventional p-n junction solar cell. Ferroelectric oxides are also stable in a wide range of mechanical, chemical and thermal conditions and can be fabricated using low-cost methods such as sol-gel thin-film deposition and sputtering. Recent work has shown how a decrease in ferroelectric layer thickness and judicious engineering of domain structures and ferroelectric-electrode interfaces can greatly increase the current harvested from ferroelectric absorber materials, increasing the power conversion efficiency from about 10(-4) to about 0.5 per cent. Further improvements in photovoltaic efficiency have been inhibited by the wide bandgaps (2.7-4 electronvolts) of ferroelectric oxides, which allow the use of only 8-20 per cent of the solar spectrum. Here we describe a family of single-phase solid oxide solutions made from low-cost and non-toxic elements using conventional solid-state methods: [KNbO3]1 - x[BaNi1/2Nb1/2O3 - δ]x (KBNNO). These oxides exhibit both ferroelectricity and a wide variation of direct bandgaps in the range 1.1-3.8 electronvolts. In particular, the x = 0.1 composition is polar at room temperature, has a direct bandgap of 1.39 electronvolts and has a photocurrent density approximately 50 times larger than that of the classic ferroelectric (Pb,La)(Zr,Ti)O3 material. The ability of KBNNO to absorb three to six times more solar energy than the current ferroelectric materials suggests a route to viable ferroelectric semiconductor-based cells for solar energy conversion and

  1. Black phosphorus saturable absorber for ultrashort pulse generation

    Energy Technology Data Exchange (ETDEWEB)

    Sotor, J., E-mail: jaroslaw.sotor@pwr.edu.pl; Sobon, G.; Abramski, K. M. [Laser and Fiber Electronics Group, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, Wroclaw 50-370 (Poland); Macherzynski, W.; Paletko, P. [Faculty of Microsystem Electronics and Photonics, Wroclaw University of Technology, Janiszewskiego 11/17, Wroclaw 50-372 (Poland)

    2015-08-03

    Low-dimensional materials, due to their unique and versatile properties, are very interesting for numerous applications in electronics and optoelectronics. Recently rediscovered black phosphorus, with a graphite-like layered structure, can be effectively exfoliated up to the single atomic layer called phosphorene. Contrary to graphene, it possesses a direct band gap controllable by the number of stacked atomic layers. For those reasons, black phosphorus is now intensively investigated and can complement or replace graphene in various photonics and electronics applications. Here, we demonstrate that black phosphorus can serve as a broadband saturable absorber and can be used for ultrashort optical pulse generation. The mechanically exfoliated ∼300 nm thick layers of black phosphorus were transferred onto the fiber core, and under pulsed excitation at 1560 nm wavelength, its transmission increases by 4.6%. We have demonstrated that the saturable absorption of black phosphorus is polarization sensitive. The fabricated device was used to mode-lock an Er-doped fiber laser. The generated optical solitons with the 10.2 nm bandwidth and 272 fs duration were centered at 1550 nm. The obtained results unambiguously show that black phosphorus can be effectively used for ultrashort pulse generation with performances similar or even better than currently used graphene or carbon nanotubes. This application of black phosphorus proves its great potential to future practical use in photonics.

  2. Cluster growing process and a sequence of magic numbers

    DEFF Research Database (Denmark)

    Solov'yov, Ilia; Solov'yov, Andrey V.; Greiner, Walter

    2003-01-01

    demonstrate that in this way all known global minimum structures of the Lennard-Jones (LJ) clusters can be found. Our method provides an efficient tool for the calculation and analysis of atomic cluster structure. With its use we justify the magic number sequence for the clusters of noble gas atoms......We present a new theoretical framework for modeling the cluster growing process. Starting from the initial tetrahedral cluster configuration, adding new atoms to the system, and absorbing its energy at each step, we find cluster growing paths up to the cluster sizes of more than 100 atoms. We...

  3. Cold tests of HOM absorber material for the ARIEL eLINAC at TRIUMF

    International Nuclear Information System (INIS)

    Kolb, P.; Laxdal, R.E.; Zvyagintsev, V.; Chao, Y.C.; Amini, B.

    2014-01-01

    At TRIUMF development of a 50 MeV electron accelerator is well under way. Five 1.3 GHz, superconducting 9-cell cavities will accelerate 10 mA electrons to a production target to produce rare isotopes. Each cavity will provide 10 MV accelerating voltage. Plans to upgrade the accelerator in the future to a small ring with ERL capabilities requires that the shunt impedance of the dipole higher order modes to be less than 10MΩ . The design of the accelerator incorporates beam line absorbers to reduce the shunt impedance of potentially dangerous dipole modes. The performance of the absorber is dependant on its electrical conductivity at the operational temperature. Measurements of the electrical conductivity in RF fields of a sample of the proposed beam line absorber material at room temperature and at its operational temperature will be presented for frequencies between 1.3 and 2.4 GHz

  4. Cold tests of HOM absorber material for the ARIEL eLINAC at TRIUMF

    Energy Technology Data Exchange (ETDEWEB)

    Kolb, P., E-mail: kolb@triumf.ca [TRIUMF, Canada' s National Laboratory for Particle and Nuclear Physics, 4004 Wesbrook Mall, Vancouver, B.C., Canada V6T 2A3 (Canada); University of British Columbia, Department of Physics and Astronomy, 6224 Agricultural Road, Vancouver, B.C., Canada V6T 1Z1 (Canada); Laxdal, R.E., E-mail: lax@triumf.ca [TRIUMF, Canada' s National Laboratory for Particle and Nuclear Physics, 4004 Wesbrook Mall, Vancouver, B.C., Canada V6T 2A3 (Canada); Zvyagintsev, V.; Chao, Y.C. [TRIUMF, Canada' s National Laboratory for Particle and Nuclear Physics, 4004 Wesbrook Mall, Vancouver, B.C., Canada V6T 2A3 (Canada); Amini, B. [TRIUMF, Canada' s National Laboratory for Particle and Nuclear Physics, 4004 Wesbrook Mall, Vancouver, B.C., Canada V6T 2A3 (Canada); University of British Columbia, Department of Physics and Astronomy, 6224 Agricultural Road, Vancouver, B.C., Canada V6T 1Z1 (Canada)

    2014-01-11

    At TRIUMF development of a 50 MeV electron accelerator is well under way. Five 1.3 GHz, superconducting 9-cell cavities will accelerate 10 mA electrons to a production target to produce rare isotopes. Each cavity will provide 10 MV accelerating voltage. Plans to upgrade the accelerator in the future to a small ring with ERL capabilities requires that the shunt impedance of the dipole higher order modes to be less than 10MΩ . The design of the accelerator incorporates beam line absorbers to reduce the shunt impedance of potentially dangerous dipole modes. The performance of the absorber is dependant on its electrical conductivity at the operational temperature. Measurements of the electrical conductivity in RF fields of a sample of the proposed beam line absorber material at room temperature and at its operational temperature will be presented for frequencies between 1.3 and 2.4 GHz.

  5. Atom-number squeezing and bipartite entanglement of two-component Bose-Einstein condensates: analytical results

    Energy Technology Data Exchange (ETDEWEB)

    Jin, G R; Wang, X W; Li, D; Lu, Y W, E-mail: grjin@bjtu.edu.c [Department of Physics, Beijing Jiaotong University, Beijing 100044 (China)

    2010-02-28

    We investigate spin dynamics of a two-component Bose-Einstein condensate with weak Josephson coupling. Analytical expressions of atom-number squeezing and bipartite entanglement are presented for atom-atom repulsive interactions. For attractive interactions, there is no number squeezing; however, the squeezing parameter is still useful to recognize the appearance of Schroedinger's cat state.

  6. Absorbent agents for clean-up of liquid hydrocarbons

    International Nuclear Information System (INIS)

    Waldmann, J.J.

    1993-01-01

    A method is described for absorbing liquid hydrocarbon from a liquid hydrocarbon-contaminated substrate comprising applying to said contaminated substrate an effective amount of a chemical absorbent composition of formula: A m B n C p wherein A m is an acid leached bentonite in a form of hydrous silicate of alumina modified by a hydrophobic alkyl (C 12 -C 24 ) amine which has been double protonized by an aliphatic acid with C 1 -C 18 carbon atoms in which m = 0 to 100% by weight of the composition; B n is a modified aminoplast resin comprised of cyanoguanidine-melamine-urea-formaldehyde in a foam form in which n is 0 to 100% by weight; and C p is a siliceous support-modified hydrophobic material in which p is 0 to 100% by weight; provided that at least one of m and n is a positive numerical value

  7. Measurement of the effective atomic numbers of compounds with cerium near to the absorption edge

    International Nuclear Information System (INIS)

    Polat, Recep; Icelli, Orhan

    2010-01-01

    In order to measure atomic, molecular and electronic cross-section; the effective atomic number, density of electron and absorption jump factor, we have first measured μ t values of compounds which are determined by mixture rule using transmission method. In order to measure experimentally the effective atomic number within absorption jump factors of compounds with Ce, the X-ray source used Am-241 whose gamma rays were stopped at secondary source (Sm), thus producing Kα and Kβ X-ray emission. The most crucial finding in this study is that measurement of the effective atomic number is not appropriate near to the absorption edge and the effective atomic number is affected by near to the absorption edge. The results obtained have been compared with theoretical values.

  8. A numerical analysis of aspects of absorbed dose in the vicinity of the interface of different materials

    Energy Technology Data Exchange (ETDEWEB)

    Tada, J [Tsukuba Univ., (Japan); Hirayama, H [National Lab. High Enregy Phys. (Japan); Katoh, K [Ibaraki Pref. Univ. Health Sci., (Japan)

    1997-12-31

    In the measurement and/or evaluation of the absorbed dose where the charged particle distribution is far from equilibrium, knowledge on the microscopic spatial distribution of the charged particle fluence is important. Spatial distribution of secondary electrons in the vicinity of an interface of materials and the values of the absorbed dose in these regions are investigated with a monte-Carlo simulation code EGS 4. There were experiments on spatial variation of the absorbed dose in the vicinity of an interface of materials. However, the behaviour of secondary electrons were discussed only broadly and qualitatively. In this study, behaviour of the secondary electrons was analysed to clarify contribution of ruling interactions to generate secondary electrons, and influence of the interface on the energy spectra of secondary electrons. 11 figs.

  9. Critical radius and critical number of gas atoms for cavities containing a Van der Waals gas

    International Nuclear Information System (INIS)

    Coghlan, W.A.; Mansur, L.K.

    1983-01-01

    The effect of gas on void nucleation and growth is particularly important for structural materials in fusion reactors because of the high production of helium by neutron-induced transmutation reactions. Gas reduces the critical radius for bias driven growth and there is a critical number of gas atoms, n/sub g/*, at which the critical radius is reduced essentially to zero. The significance of this is that the time interval to the accumulation of n/sub g/* gas atoms may determine the time to the onset of bias driven swelling where n/sub g/* is large. In previous papers these critical quantities were given for an ideal gas. Recently, we presented the results for a Van der Waals gas. Here the derivation of these relations is presented and further results of calculations are given. At low temperatures (high pressures) the results depart from those of the ideal gas, with the critical number affected more strongly than the critical radius. Comparisons are made with earlier calculations

  10. Preparation and Properties of Moisture-absorbing Film Impregnated with Polyacrylic Acid Partial Sodium Salt Material

    International Nuclear Information System (INIS)

    Lee, Youn Suk; Park, Insik; Choi, Hong Yeol

    2014-01-01

    Moisture is a major factor causing the deteriorative physical change, microbial growth, and chemical reaction of the products. In this study, the moisture absorbing composite films have been prepared with moisture absorbing material of polyacrylic acid partial sodium salt (PAPSS) impregnated on LLDPE polymer for the functional packaging applications. The results showed that PAPSS impregnated film illustrated uniformly dispersed PAPSS particles in the LLDPE polymer matrix. The transparency of the PAPSS impregnated film decreased slightly at higher PAPSS concentrations. An increase in the PAPSS content for moisture-absorbing films showed a similar decrease in tensile strength, percent elongation at break, and tear strength. Their values of films impregnated with PAPSS of 0.5, 1, and 2% showed no significant difference. Meanwhile, 4% PAPSS films significantly decreased the values of mechanical properties compared to the films impregnated with different PAPSS levels. Values of the oxygen permeability and water vapor permeability for PAPSS impregnated films decreased significantly with greater PAPSS. The results indicate that 4% PAPSS impregnated in LLDPE films had high affinity of moisture absorbencies compared to the other films. The mathematical equation that best described the moisture sorption isotherm of each film sample was the GAB equation at 25 .deg. C. The crystallization and melting temperatures of PAPSS films were influenced by the addition of PAPSS material, but showed good thermal stability

  11. Preparation and Properties of Moisture-absorbing Film Impregnated with Polyacrylic Acid Partial Sodium Salt Material

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Youn Suk; Park, Insik [Yonsei University, Wonju (Korea, Republic of); Choi, Hong Yeol [CJ Cheiljedang, Seoul (Korea, Republic of)

    2014-08-15

    Moisture is a major factor causing the deteriorative physical change, microbial growth, and chemical reaction of the products. In this study, the moisture absorbing composite films have been prepared with moisture absorbing material of polyacrylic acid partial sodium salt (PAPSS) impregnated on LLDPE polymer for the functional packaging applications. The results showed that PAPSS impregnated film illustrated uniformly dispersed PAPSS particles in the LLDPE polymer matrix. The transparency of the PAPSS impregnated film decreased slightly at higher PAPSS concentrations. An increase in the PAPSS content for moisture-absorbing films showed a similar decrease in tensile strength, percent elongation at break, and tear strength. Their values of films impregnated with PAPSS of 0.5, 1, and 2% showed no significant difference. Meanwhile, 4% PAPSS films significantly decreased the values of mechanical properties compared to the films impregnated with different PAPSS levels. Values of the oxygen permeability and water vapor permeability for PAPSS impregnated films decreased significantly with greater PAPSS. The results indicate that 4% PAPSS impregnated in LLDPE films had high affinity of moisture absorbencies compared to the other films. The mathematical equation that best described the moisture sorption isotherm of each film sample was the GAB equation at 25 .deg. C. The crystallization and melting temperatures of PAPSS films were influenced by the addition of PAPSS material, but showed good thermal stability.

  12. Computerized simulation of the mechanical behavior of wood-filled shock absorbers of radioactive materials transport casks

    International Nuclear Information System (INIS)

    Neumann, Martin; Wille, Frank

    2011-01-01

    In Germany the mechanical component inspection of transport containers for radioactive materials is performed by BAM (Bundesanstalt fuer Materialforschung und -pruefung) under consideration of national and international standards and guidelines. Experimental and calculative (analytical and numerical) techniques combined with material and/or component testing are the basis of assessment concepts according the state of the art. The authors describe the experiences of BAM concerning assessment and description of the mechanical behavior of shock absorbing components, including modeling strategies, material models, drop tests and experiment-calculation comparison. Energy absorbing components are used to reduce the impact forces at the container in case of a transport accident. In Germany wood filled thin-walled constructions are used. The deformation behavior of the wood is a main part of the calculative simulation procedures in comparison with experimental tests.

  13. IAEA technical meeting on atomic and plasma-material interaction data for fusion science technology. Summary report

    International Nuclear Information System (INIS)

    Clark, R.E.H.

    2003-10-01

    The proceedings and conclusions of the Technical Meeting on 'Atomic and Plasma- Material Interaction Data for Fusion Science Technology' held in Juelich, Germany on October 28-31 are summarized. During the course of the meetings working groups were formed to review the status of specific areas of atomic, molecular and material physics of relevance to fusion and to make recommendations on data needs in fusion from these areas. The reports of those working groups are summarized and the complete reports included as appendices. This meeting brought together over fifty leading scientists in fusion related data. Results of research in a number of topics were presented and very useful discussions were held. The meeting was extremely successful. (author)

  14. Chemical reaction between single hydrogen atom and graphene

    International Nuclear Information System (INIS)

    Ito, Atsushi; Nakamura, Hiroaki; Takayama, Arimichi

    2007-04-01

    We study chemical reaction between a single hydrogen atom and a graphene, which is the elemental reaction between hydrogen and graphitic carbon materials. In the present work, classical molecular dynamics simulation is used with modified Brenner's empirical bond order potential. The three reactions, that is, absorption reaction, reflection reaction and penetration reaction, are observed in our simulation. Reaction rates depend on the incident energy of the hydrogen atom and the graphene temperature. The dependence can be explained by the following mechanisms: (1) The hydrogen atom receives repulsive force by π-electrons in addition to nuclear repulsion. (2) Absorbing the hydrogen atom, the graphene transforms its structure to the 'overhand' configuration such as sp 3 state. (3) The hexagonal hole of the graphene is expanded during the penetration of the hydrogen atom. (author)

  15. Solar radiation absorbing material

    Science.gov (United States)

    Googin, John M.; Schmitt, Charles R.; Schreyer, James M.; Whitehead, Harlan D.

    1977-01-01

    Solar energy absorbing means in solar collectors are provided by a solar selective carbon surface. A solar selective carbon surface is a microporous carbon surface having pores within the range of 0.2 to 2 micrometers. Such a surface is provided in a microporous carbon article by controlling the pore size. A thermally conductive substrate is provided with a solar selective surface by adhering an array of carbon particles in a suitable binder to the substrate, a majority of said particles having diameters within the range of about 0.2-10 microns.

  16. Calculation of atom displacement cross section for structure material

    International Nuclear Information System (INIS)

    Liu Ping; Xu Yiping

    2015-01-01

    The neutron radiation damage in material is an important consideration of the reactor design. The radiation damage of materials mainly comes from atom displacements of crystal structure materials. The reaction cross sections of charged particles, cross sections of displacements per atom (DPA) and KERMA are the basis of radiation damage calculation. In order to study the differences of DPA cross sections with different codes and different evaluated nuclear data libraries, the DPA cross sections for structure materials were calculated with UNF and NJOY codes, and the comparisons of results were given. The DPA cross sections from different evaluated nuclear data libraries were compared. And the comparison of DPA cross sections between NJOY and Monte Carlo codes was also done. The results show that the differences among these evaluated nuclear data libraries exist. (authors)

  17. Atomic and plasma-material interaction data for fusion. V. 3

    International Nuclear Information System (INIS)

    1992-01-01

    This volume of Atomic and Plasma-Material Interaction Data for Fusion is devoted to atomic collision processes of helium atoms and of beryllium and boron atoms and ions in fusion plasmas. Most of the articles included in this volume are extended versions of the contributions presented at the IAEA experts' meetings on Atomic Data for Helium Beam Fusion Alpha Particle Diagnostics and on the Atomic Database for Beryllium and Boron, held in June 1991 at the IAEA headquarters in Vienna, or have resulted from the cross-section data analyses and evaluations performed by the working groups of these meetings. Refs, figs and tabs

  18. Absorbing rods for nuclear fast neutron reactor absorbing assembly

    International Nuclear Information System (INIS)

    Aji, M.; Ballagny, A.; Haze, R.

    1986-01-01

    The invention proposes a neutron absorber rod for neutron absorber assembly of a fast neutron reactor. The assembly comprises a bundle of vertical rods, each one comprising a stack of pellets made of a neutron absorber material contained in a long metallic casing with a certain radial play with regard to this casing; this casing includes traps for splinters from the pellets which may appear during reactor operation, at the level of contact between adjacent pellets. The present invention prevents the casing from rupture involved by the disintegration of the pellets producing pieces of boron carbide of high hardness [fr

  19. Atomic and Plasma-Material Interaction Data for Fusion. V. 16

    International Nuclear Information System (INIS)

    Braams, B.J.; Chung, H.-K.

    2014-03-01

    A wide variety of atomic, molecular, radiative and plasma-wall interaction processes involving a mixture of atoms, ions and molecules occur in the plasmas produced in nuclear fusion experiments. In the low temperature divertor and near wall region, molecules and molecular ions are formed. The plasma particles react with electrons and with each other. Plasma modelling requires cross-sections and rate coefficients for all these processes, and in addition spectral signatures to support interpretation of data from fusion experiments. The mission of the International Atomic Energy Agency Nuclear Data Section (IAEA/NDS) in the area of atomic and molecular data is to enhance the competencies of Member States in their research into nuclear fusion through the provision of internationally recommended atomic, molecular, plasma-material interaction and material properties databases. One mechanism by which the IAEA pursues this mission is the Coordinated Research Project (CRP). The present volume of Atomic and Plasma-Material Interaction Data for Fusion contains contributions from participants in the CRP 'Atomic and Molecular Data for Plasma Modelling' (2004-2008). This CRP was concerned with data for processes in the near wall and divertor plasma and plasma-wall interaction in fusion experiments, with focus on cross-sections for molecular reactions. Participants in the CRP came from 14 different institutes, many with strong ties to fusion plasma modelling and experiment. D. Humbert of the Nuclear Data Section was scientific secretary of the CRP. Participants' contributions for this volume were collected and refereed after the conclusion of the CRP

  20. Thermally tunable broadband omnidirectional and polarization-independent super absorber using phase change material VO2

    Directory of Open Access Journals (Sweden)

    Zhejun Liu

    Full Text Available In this letter, we numerically demonstrate a thermally tunable super absorber by using phase change material VO2 as absorbing layer in metal-insulator-metal structure. An omnidirectional super absorption at λ=2.56μm can be realized by heating the patterned grating VO2 film due to magnetic resonance mechanism. Furthermore, a broadband super absorption higher than 0.8 in the entire 1.6μm–4μm region is achieved when VO2 film is patterned chessboard structure and transformed to metal phase beyond transition temperature. This broadband super absorption can be fulfilled in a wide range of incident angle (0°–70° and under all polarization conditions. Keywords: Phase change material, Metal-insulator-metal, Super absorption, Magnetic resonance

  1. Improvements in or relating to X-ray apparatus

    International Nuclear Information System (INIS)

    1981-01-01

    In this invention an apparatus is described for producing X-ray radiation. It comprises a target which, in use, is exposed to an electron beam so as to produce a conical beam of X-ray radiation, a primary collimator with an opening defining the largest desired angle of the conical beam of radiation and a first electron absorber made from one or more elements having an atomic number lower than that of copper, (aluminium or graphite) and a second electron absorber, made from a similar material, mounted in the opening of the primary collimator, with dimensions similar to those of the opening. The effective cross-section for producing x-ray radiation increases with the atomic number and the electron absorption is proportional to the density. With the lower atomic number of the electron absorber material, the proportion of additional X-radiation arising is reduced. The problem of the reduced electron absorption is overcome by the use of two electron absorbers. (U.K.)

  2. Electrochemical Corrosion Testing of Neutron Absorber Materials

    International Nuclear Information System (INIS)

    Tedd Lister; Ron Mizia; Sandra Birk; Brent Matteson; Hongbo Tian

    2006-01-01

    The Yucca Mountain Project (YMP) has been directed by DOE-RW to develop a new repository waste package design based on the transport, aging, and disposal canister (TAD) system concept. A neutron poison material for fabrication of the internal spent nuclear fuel (SNF) baskets for these canisters needs to be identified. A material that has been used for criticality control in wet and dry storage of spent nuclear fuel is borated stainless steel. These stainless products are available as an ingot metallurgy plate product with a molybdenum addition and a powder metallurgy product that meets the requirements of ASTM A887, Grade A. A new Ni-Cr-Mo-Gd alloy has been developed by the Idaho National Laboratory (INL) with its research partners (Sandia National Laboratory and Lehigh University) with DOE-EM funding provided by the National Spent Nuclear Fuel Program (NSNFP). This neutron absorbing alloy will be used to fabricate the SNF baskets in the DOE standardized canister. The INL has designed the DOE Standardized Spent Nuclear Fuel Canister for the handling, interim storage, transportation, and disposal in the national repository of DOE owned spent nuclear fuel (SNF). A corrosion testing program is required to compare these materials in environmental conditions representative of a breached waste canister. This report will summarize the results of crevice corrosion tests for three alloys in solutions representative of ionic compositions inside the waste package should a breech occur. The three alloys in these tests are Neutronit A978 (ingot metallurgy, hot rolled), Neutrosorb 304B4 Grade A (powder metallurgy, hot rolled), and Ni-Cr-Mo-Gd alloy (ingot metallurgy, hot rolled)

  3. Preparation and characterization of super absorbent polymer from sugarcane bagasse

    International Nuclear Information System (INIS)

    Wiwien Andriyanti; Suyanti; Ngasifudin

    2012-01-01

    Sugarcane bagasse is a source of biomass which large enough numbers and has not been fully exploited. At this time has developed a super absorbent polymer material of sugarcane bagasse that can absorb water up to several times of its own weight and keep this water. Super absorbent polymers can be used as a soil conditioner that can be used as an absorber and storage of ground water, the giver of nutrients for plants, and can improve soil properties. The purpose of this study is to make and characterization of super absorbent polymer (PCS) from sugarcane bagasse. Preparation of super absorbent polymers (PCS) has been done by grafting method using ionizing radiation from Electron Beam Engineering (MBE) 350 mA keV/10. Irradiation process carried out with a dose variation of 20, 35, and 50 kGy. Increasing doses of radiation will increase the percentage fraction of transplantation (grafting) and the fraction of water absorption ability (swelling ratio). (author)

  4. Two-Photon Absorbing Molecules as Potential Materials for 3D Optical Memory

    Directory of Open Access Journals (Sweden)

    Kazuya Ogawa

    2014-01-01

    Full Text Available In this review, recent advances in two-photon absorbing photochromic molecules, as potential materials for 3D optical memory, are presented. The investigations introduced in this review indicate that 3D data storage processing at the molecular level is possible. As 3D memory using two-photon absorption allows advantages over existing systems, the use of two-photon absorbing photochromic molecules is preferable. Although there are some photochromic molecules with good properties for memory, in most cases, the two-photon absorption efficiency is not high. Photochromic molecules with high two-photon absorption efficiency are desired. Recently, molecules having much larger two-photon absorption cross sections over 10,000 GM (GM= 10−50 cm4 s molecule−1 photon−1 have been discovered and are expected to open the way to realize two-photon absorption 3D data storage.

  5. Hybrid waste filler filled bio-polymer foam composites for sound absorbent materials

    Science.gov (United States)

    Rus, Anika Zafiah M.; Azahari, M. Shafiq M.; Kormin, Shaharuddin; Soon, Leong Bong; Zaliran, M. Taufiq; Ahraz Sadrina M. F., L.

    2017-09-01

    Sound absorption materials are one of the major requirements in many industries with regards to the sound insulation developed should be efficient to reduce sound. This is also important to contribute in economically ways of producing sound absorbing materials which is cheaper and user friendly. Thus, in this research, the sound absorbent properties of bio-polymer foam filled with hybrid fillers of wood dust and waste tire rubber has been investigated. Waste cooking oil from crisp industries was converted into bio-monomer, filled with different proportion ratio of fillers and fabricated into bio-polymer foam composite. Two fabrication methods is applied which is the Close Mold Method (CMM) and Open Mold Method (OMM). A total of four bio-polymer foam composite samples were produce for each method used. The percentage of hybrid fillers; mixture of wood dust and waste tire rubber of 2.5 %, 5.0%, 7.5% and 10% weight to weight ration with bio-monomer. The sound absorption of the bio-polymer foam composites samples were tested by using the impedance tube test according to the ASTM E-1050 and Scanning Electron Microscope to determine the morphology and porosity of the samples. The sound absorption coefficient (α) at different frequency range revealed that the polymer foam of 10.0 % hybrid fillers shows highest α of 0.963. The highest hybrid filler loading contributing to smallest pore sizes but highest interconnected pores. This also revealed that when highly porous material is exposed to incident sound waves, the air molecules at the surface of the material and within the pores of the material are forced to vibrate and loses some of their original energy. This is concluded that the suitability of bio-polymer foam filled with hybrid fillers to be used in acoustic application of automotive components such as dashboards, door panels, cushion and etc.

  6. Experimental study of stopping powers for ions of intermediate atomic numbers

    International Nuclear Information System (INIS)

    Bucher, R.G.

    1975-01-01

    A technique has been developed to measure the energy loss as a function of ion atomic number for the fragments emitted by the spontaneous fission of 252 Cf; the atomic numbers of the fragments were directly measured by the detection of a characteristic K x-ray. The measured energy losses were compared with the theories of Lindhard and of Firsov, with the tabulation of Northcliffe and Schilling, and with the semiempirical formula of Moak and Brown. For the light fragments the measured values are in good agreement with the predictions of Moak--Brown and Northcliffe--Schilling; for the heavy fragments the measured values are approximately midway between the prediction of Moak--Brown and Northcliffe--Schilling and those of Lindhard for xi/sub epsilon/ = 2. The difference in the stopping powers for adjacent ion atomic numbers Z 1 was concluded to be (1.8 +- 0.2) percent for 40 less than or equal to Z 1 less than or equal to 45 at a velocity of 1.36 cm/ns and (2.0 +- 0.1) percent for 53 less than or equal to Z 1 less than or equal to 58 at a velocity of 1.04 cm/ns

  7. Development and mastering of production of dysprosium hafnate as absorbing material for control rods of promising thermal neutron reactors

    International Nuclear Information System (INIS)

    Zakharov, A.V.; Risovany, V.D.; Muraleva, E.M.; Sokolov, V.F.

    2011-01-01

    The main advantages of dysprosium hafnate as an absorbing material for LWR control rods are the following: -) unlimited radiation resistance; - two absorbing components, Dy and Hf, increasing physical efficiency of the material compared to Dy 2 O 3 -TiO 2 and alloy 80% Ag - 15% In - 5% Cd; -) variability of physical efficiency by changing a composition, but maintaining other performance characteristics of the material; -) high process-ability due to the absence of phase transients and single-phase structure (solid solution); -) production of high density pellets. Lab-scale mastering of dysprosium hafnate pellets production showed a possibility of material synthesis using a solid-phase method, as well as of dysprosium hafnate pellets production by cold pressing and subsequent sintering. Within a whole range of examined compositions (23 mol% - 75 mol% Dy 2 O 3 ), a single-phase material with a highly radiation resistant fluorite-like structure was produced. Experiments on cold pressing and sintering of pellets confirmed a possibility of producing high quality dysprosium hafnate pellets from synthesized powder. A pilot batch of dysprosium hafnate pellets with standard sizes was produced. The standard sizes corresponded to the absorbing elements of the WWER-1000 control rods and met the main requirements to the absorbing element columns. The pilot batch size was approximately 6 kg. Acceptance testing of the pilot batch of dysprosium hafnate pellets was conducted, fulfillment of the requirements of technical conditions was checked and preirradiation properties of the pellets were examined. High quality of the produced pellets was confirmed, thus, demonstrating a real possibility of producing large batches of the dysprosium hafnate pellets. The next step is the production of test absorbing elements and cluster assemblies for the WWER-1000 control rods with their further installation for pilot operation at one of the Russian nuclear power plants

  8. Atomic scale modelling of materials of the nuclear fuel cycle

    International Nuclear Information System (INIS)

    Bertolus, M.

    2011-10-01

    This document written to obtain the French accreditation to supervise research presents the research I conducted at CEA Cadarache since 1999 on the atomic scale modelling of non-metallic materials involved in the nuclear fuel cycle: host materials for radionuclides from nuclear waste (apatites), fuel (in particular uranium dioxide) and ceramic cladding materials (silicon carbide). These are complex materials at the frontier of modelling capabilities since they contain heavy elements (rare earths or actinides), exhibit complex structures or chemical compositions and/or are subjected to irradiation effects: creation of point defects and fission products, amorphization. The objective of my studies is to bring further insight into the physics and chemistry of the elementary processes involved using atomic scale modelling and its coupling with higher scale models and experimental studies. This work is organised in two parts: on the one hand the development, adaptation and implementation of atomic scale modelling methods and validation of the approximations used; on the other hand the application of these methods to the investigation of nuclear materials under irradiation. This document contains a synthesis of the studies performed, orientations for future research, a detailed resume and a list of publications and communications. (author)

  9. Development of microwave absorbing materials prepared from a polymer binder including Japanese lacquer and epoxy resin

    Science.gov (United States)

    Iwamaru, T.; Katsumata, H.; Uekusa, S.; Ooyagi, H.; Ishimura, T.; Miyakoshi, T.

    Microwave absorption composites were synthesized from a poly urushiol epoxy resin (PUE) mixed with one of microwave absorbing materials; Ni-Zn ferrite, Soot, Black lead, and carbon nano tube (CNT) to investigate their microwave absorption properties. PUE binders were specially made from Japanese lacquer and epoxy resin, where Japanese lacquer has been traditionally used for bond and paint because it has excellent beauty. Japanese lacquer solidifies with oxygen contained in air's moisture, which has difficulty in making composite, but we improved Japanese lacquer's solidification properties by use of epoxy resin. We made 10 mm thickness composite samples and cut them into toroidal shape to measure permittivity, permeability, and reflection loss in frequencies ranging from 50 Hz to 20 GHz. Electric magnetic absorber's composites synthesized from a PUE binders mixed either with Soot or CNT showed significantly higher wave absorption over -27 dB than the others at frequencies around 18 GHz, although Japanese lacquer itself doesn't affect absorption. This means Japanese lacquer can be used as binder materials for microwave absorbers.

  10. Development of FeCoB/Graphene Oxide based microwave absorbing materials for X-Band region

    International Nuclear Information System (INIS)

    Das, Sukanta; Chandra Nayak, Ganesh; Sahu, S.K.; Oraon, Ramesh

    2015-01-01

    This work explored the microwave absorption capability of Graphene Oxide and Graphene Oxide coated with FeCoB for stealth technology. Epoxy based microwave absorbing materials were prepared with 30% loading of Graphene Oxide, FeCoB alloy and Graphene Oxide coated with FeCoB. Graphene Oxide and FeCoB were synthesized by Hummer's and Co-precipitation methods, respectively. The filler particles were characterized by FESEM, XRD and Vibrating Sample Magnetometer techniques. Permittivity, permeability and reflection loss values of the composite absorbers were measured with vector network analyzer which showed a reflection loss value of −7.86 dB, at 10.72 GHz, for single layered Graphene Oxide/Epoxy based microwave absorbers which can be correlated to the absorption of about 83.97% of the incident microwave energy. Reflection loss value of FeCoB/Epoxy based microwave absorber showed −13.30 dB at 11.67 GHz, which corresponded to maximum absorption of 93.8%. However, reflection loss values of Graphene Oxide coated with FeCoB/Epoxy based single-layer absorber increased to −22.24 dB at 12.4 GHz which corresponds to an absorption of 99% of the incident microwave energy. - Highlights: • FeCoB coated Graphene Oxide (GO) was synthesized by co-precipitation method. • GO, FeCoB and GO@FeCoB based microwave absorbers were developed with Epoxy matrix. • GO and FeCoB/Epoxy absorbers showed −7.86 & −13.30 dB reflection loss, respectively. • Maximum Reflection loss of −22.24 dB was achieved with GO@FeCoB/Epoxy absorber

  11. Sapphire: a better material for atomization and in situ collection of silver volatile species for atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Musil, Stanislav, E-mail: stanomusil@biomed.cas.cz; Matoušek, Tomáš; Dědina, Jiří

    2015-06-01

    Sapphire is presented as a high temperature and corrosion resistant material of an optical tube of an atomizer for volatile species of Ag generated by the reaction with NaBH{sub 4}. The modular atomizer design was employed which allowed to carry out the measurements in two modes: (i) on-line atomization and (ii) in situ collection (directly in the optical tube) by means of excess of O{sub 2} over H{sub 2} in the carrier gas during the trapping step and vice versa in the volatilization step. In comparison with quartz atomizers, the sapphire tube atomizer provides a significantly increased atomizer lifetime as well as substantially improved repeatability of the Ag in situ collection signals shapes. In situ collection of Ag in the sapphire tube atomizer was highly efficient (> 90%). Limit of detection in the on-line atomization mode and in situ collection mode, respectively, was 1.2 ng ml{sup −1} and 0.15 ng ml{sup −1}. - Highlights: • Sapphire was tested as a new material of an atomizer tube for Ag volatile species. • Two measurement modes were investigated: on-line atomization and in situ collection. • In situ collection of Ag was highly efficient (> 90%) with LOD of 0.15 ng ml{sup −1}. • No devitrification of the sapphire tube observed in the course of several months.

  12. Burnable neutron absorbers

    International Nuclear Information System (INIS)

    Radford, K.C.; Carlson, W.G.

    1985-01-01

    This patent deals with the fabrication of pellets for neutron absorber rods. Such a pellet includes a matrix of a refractory material which may be aluminum or zirconium oxide, and a burnable poison distributed throughout the matrix. The neutron absorber material may consist of one or more elements or compounds of the metals boron, gadolinium, samarium, cadmium, europium, hafnium, dysprosium and indium. The method of fabricating pellets of these materials outlined in this patent is designed to produce pores or voids in the pellets that can be used to take up the expansion of the burnable poison and to absorb the helium gas generated. In the practice of this invention a slurry of Al 2 O 3 is produced. A hard binder is added and the slurry and binder are spray dried. This powder is mixed with dry B 4 C powder, forming a homogeneous mixture. This mixture is pressed into green tubes which are then sintered. During sintering the binder volatilizes leaving a ceramic with nearly spherical high-density regions of

  13. Scholar-activating teaching materials on quantum physics. Pt. 3. Foundations of atomic physics

    International Nuclear Information System (INIS)

    Huebel, Horst

    2010-01-01

    Traditionally in the center of the interest on quantum physics referring to schools the question lies, whether electrons or photons are now particles or waves, a question, which is often characterized by the phrase ''wave-particle dualism'', which notoriously not exists in its original meaning. Against that by the author - on the base of important preparatory works of Kueblbeck and Mueller - a new concept of quantum physics for the school was proposed, which puts ''basic facts'' in the foreground, comparable with the Kueblbeck-Mueller ''characteristic features''. The ''basic facts'' are similar to axioms of quantum physics, by means of them a large number of experiments and phenomena can be ''explained'' at least qualitatively - in a heuristic way -. Instead of the so-called ''wave-particle dualism'' uncertainty and complementarity are put in the foreground. The new concept is in the Internet under http://www.forphys.de extensively presented with many further materials. In the partial volumes of this publication manifold and carefully elaborated teaching materials are presented, by which scholars can get themselves the partial set of quantum physics referring to schools by different methods like learning at stations, short referates, Internet-research, group puzzle, the query-sheet or the card-index method etc. In the present 3. part materials are prepared, by which scholars can get foundations of atomic physics and interpret in the sense of the ''basic facts or quantum physics''. Here deals it thus with discrete energy levels, the linear potential box, with atomic models, the atomic structure, the tunnel effect, and - because curricula it often require - also with the Schroedinger equation. The materials can also be usefully applied in other concepts.

  14. Atoms in strong laser fields

    International Nuclear Information System (INIS)

    L'Huillier, A.

    2002-01-01

    When a high-power laser focuses into a gas of atoms, the electromagnetic field becomes of the same magnitude as the Coulomb field which binds a 1s electron in a hydrogen atom. 3 highly non-linear phenomena can happen: 1) ATI (above threshold ionization): electrons initially in the ground state absorb a large number of photons, many more than the minimum number required for ionization; 2) multiple ionization: many electrons can be emitted one at a time, in a sequential process, or simultaneously in a mechanism called direct or non-sequential; and 3) high order harmonic generation (HHG): efficient photon emission in the extreme ultraviolet range, in the form of high-order harmonics of the fundamental laser field can occur. The theoretical problem consists in solving the time dependent Schroedinger equation (TDSE) that describes the interaction of a many-electron atom with a laser field. A number of methods have been proposed to solve this problem in the case of a hydrogen atom or a single-active electron atom in a strong laser field. A large effort is presently being devoted to go beyond the single-active approximation. The understanding of the physics of the interaction between atoms and strong laser fields has been provided by a very simple model called ''simple man's theory''. A unified view of HHG, ATI, and non-sequential ionization, originating from the simple man's model and the strong field approximation, expressed in terms of electrons trajectories or quantum paths is slowly emerging. (A.C.)

  15. Platinum clusters with precise numbers of atoms for preparative-scale catalysis.

    Science.gov (United States)

    Imaoka, Takane; Akanuma, Yuki; Haruta, Naoki; Tsuchiya, Shogo; Ishihara, Kentaro; Okayasu, Takeshi; Chun, Wang-Jae; Takahashi, Masaki; Yamamoto, Kimihisa

    2017-09-25

    Subnanometer noble metal clusters have enormous potential, mainly for catalytic applications. Because a difference of only one atom may cause significant changes in their reactivity, a preparation method with atomic-level precision is essential. Although such a precision with enough scalability has been achieved by gas-phase synthesis, large-scale preparation is still at the frontier, hampering practical applications. We now show the atom-precise and fully scalable synthesis of platinum clusters on a milligram scale from tiara-like platinum complexes with various ring numbers (n = 5-13). Low-temperature calcination of the complexes on a carbon support under hydrogen stream affords monodispersed platinum clusters, whose atomicity is equivalent to that of the precursor complex. One of the clusters (Pt 10 ) exhibits high catalytic activity in the hydrogenation of styrene compared to that of the other clusters. This method opens an avenue for the application of these clusters to preparative-scale catalysis.The catalytic activity of a noble metal nanocluster is tied to its atomicity. Here, the authors report an atom-precise, fully scalable synthesis of platinum clusters from molecular ring precursors, and show that a variation of only one atom can dramatically change a cluster's reactivity.

  16. The mystery of missing species in atom probe tomography of composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Karahka, M.; Xia, Y.; Kreuzer, H. J. [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia B3H 3J5 (Canada)

    2015-08-10

    There is a serious problem in atom probe tomography of composite materials such as oxides that even from stoichiometric samples one observes non-stoichiometric ion yields. We present a quantitative model that explains the non-stoichiometry allowing a fit to experimental data of ion yields as a function of applied field to extract activation barriers and prefactors. The numbers are confirmed by density functional theory. We also show that for oxides the missing oxygen is thermally desorbed as neutral O{sub 2}, either directly or associatively. Finally, we suggest methods to improve the experimental setup.

  17. Multiple myeloma among atomic bomb survivors in Hiroshima and Nagasaki, 1950-76: relationship to radiation dose absorbed by marrow

    International Nuclear Information System (INIS)

    Ichimaru, M.; Ishimaru, T.; Mikami, M.; Matsunaga, M.

    1982-01-01

    The relationship between atomic bomb exposure and the incidence of multiple myeloma has been examined in a fixed cohort of atomic bomb survivors and controls in the life-span study sample for Hiroshima and Nagasaki. From October 1950 to December 1976, 29 cases of multiple myeloma were confirmed in this sample. Our analysis shows that the standardized relative risk (RR) adjusted for city, sex, and age at the time of bombings (ATB) increased with marrow-absorbed radiation dose. The increased RR does not appear to differ between cities or sexes and is demonstrable only for those survivors whose age ATB was between 20 and 59 years. The estimated risk in these individuals is approximately 0.48 cases/million person-years/rad for bone marrow total dose. This excess risk did not become apparent in individuals receiving 50 rad or more in marrow total dose until 20 years or more after exposure

  18. The Effects of Water-Absorbent Materials on Water Supply for Tree Planting in the Semi-Arid Regions

    Directory of Open Access Journals (Sweden)

    Gholam Reza Davarpanah Davarpanah

    2005-03-01

    Full Text Available Numerous studies have so far been focused on increasing irrigation efficiency through such measures as soil moisture retention and soil moisture capacity as well as improving soil physical conditions. In this study, surface runoff reduction, deep penetration of rain water, and use of rain water at irrigation sites with the help of water absorbent chemicals were investigated as measures of supplying for tree water demand and also of reducing drought effects. The absorbent material was purchased from Iran Polymer Research Center. The experimental design included three independent experiments in a completely randomized block design (CRBD with 5 treatments (0, 50, 100, 150 and 200 gr. of the absorbent material and three replications. The tree species used in the experiments were Amygdalus sp., Vitis vinifera, and Pistacia vera. There were 5 experimental units with 4 trees planted 3×3 meters apart. Appropriate amounts of the test material (absorbent were mixed with soil. Three characters of survival including: growth diameter, height, and canopy cover were recorded 4 times a year over two consecutive years. Mstat-c statistical software was used in the statistical analysis (Factor option. Results showed that the tree species had significant differences in their survival due to their genetic and physiological characteristics, so that the species of Vitis vinifera and Pistacia vera recorded the minimum and maximum survival values, respectively. Data collection within the present study is suggested to be continued and similar studies with light and sandy textured soils under greenhouse conditions are needed in order to gain more accurate information on these effects.

  19. An Estimation of the Number and Size of Atoms in a Printed Period

    Science.gov (United States)

    Schaefer, Beth; Collett, Edward; Tabor-Morris, Anne; Croman, Joseph

    2011-01-01

    Elementary school students learn that atoms are very, very small. Students are also taught that atoms (and molecules) are the fundamental constituents of the material world. Numerical values of their size are often given, but, nevertheless, it is difficult to imagine their size relative to one's everyday surroundings. In order for students to…

  20. Effective atomic number, electron density and kerma of gamma ...

    Indian Academy of Sciences (India)

    Abstract. An attempt has been made to estimate the effective atomic number, electron density (0.001 to 105 MeV) and kerma (0.001 to 20 MeV) of gamma radiation for a wide range of oxides of ... The lanthanide oxides find remarkable applications in the field of medicine, biology, nuclear engineering and space technology.

  1. Determination of arsenic in geological materials by electrothermal atomic-absorption spectrometry after hydride generation

    Science.gov (United States)

    Sanzolone, R.F.; Chao, T.T.; Welsch, E.P.

    1979-01-01

    Rock and soil samples are decomposed with HClO4-HNO3; after further treatment, arsine is generated and absorbed in a dilute silver nitrate solution. Aliquots of this solution are injected into a carbon rod atomizer. Down to 1 ppm As in samples can be determined and there are no significant interferences, even from chromium in soils. Good results were obtained for geochemical reference samples. ?? 1979.

  2. Theoretical realization of cluster-assembled hydrogen storage materials based on terminated carbon atomic chains.

    Science.gov (United States)

    Liu, Chun-Sheng; An, Hui; Guo, Ling-Ju; Zeng, Zhi; Ju, Xin

    2011-01-14

    The capacity of carbon atomic chains with different terminations for hydrogen storage is studied using first-principles density functional theory calculations. Unlike the physisorption of H(2) on the H-terminated chain, we show that two Li (Na) atoms each capping one end of the odd- or even-numbered carbon chain can hold ten H(2) molecules with optimal binding energies for room temperature storage. The hybridization of the Li 2p states with the H(2)σ orbitals contributes to the H(2) adsorption. However, the binding mechanism of the H(2) molecules on Na arises only from the polarization interaction between the charged Na atom and the H(2). Interestingly, additional H(2) molecules can be bound to the carbon atoms at the chain ends due to the charge transfer between Li 2s2p (Na 3s) and C 2p states. More importantly, dimerization of these isolated metal-capped chains does not affect the hydrogen binding energy significantly. In addition, a single chain can be stabilized effectively by the C(60) fullerenes termination. With a hydrogen uptake of ∼10 wt.% on Li-coated C(60)-C(n)-C(60) (n = 5, 8), the Li(12)C(60)-C(n)-Li(12)C(60) complex, keeping the number of adsorbed H(2) molecules per Li and stabilizing the dispersion of individual Li atoms, can serve as better building blocks of polymers than the (Li(12)C(60))(2) dimer. These findings suggest a new route to design cluster-assembled hydrogen storage materials based on terminated sp carbon chains.

  3. Dynamic testing of airplane shock-absorbing struts

    Science.gov (United States)

    Langer, P; Thome, W

    1932-01-01

    Measurement of perpendicular impacts of a landing gear with different shock-absorbing struts against the drum testing stand. Tests were made with pneumatic shock absorbers having various degrees of damping, liquid shock absorbers, steel-spring shock absorbers and rigid struts. Falling tests and rolling tests. Maximum impact and gradual reduction of the impacts in number and time in the falling tests. Maximum impact and number of weaker impacts in rolling tests.

  4. A model for acoustic absorbent materials derived from coconut fiber

    Directory of Open Access Journals (Sweden)

    Ramis, J.

    2014-03-01

    Full Text Available In the present paper, a methodology is proposed for obtaining empirical equations describing the sound absorption characteristics of an absorbing material obtained from natural fibers, specifically from coconut. The method, which was previously applied to other materials, requires performing measurements of air-flow resistivity and of acoustic impedance for samples of the material under study. The equations that govern the acoustic behavior of the material are then derived by means of a least-squares fit of the acoustic impedance and of the propagation constant. These results can be useful since they allow the empirically obtained analytical equations to be easily incorporated in prediction and simulation models of acoustic systems for noise control that incorporate the studied materials.En este trabajo se describe el proceso seguido para obtener ecuaciones empíricas del comportamiento acústico de un material absorbente obtenido a partir de fibras naturales, concretamente el coco. El procedimiento, que ha sido ensayado con éxito en otros materiales, implica la realización de medidas de impedancia y resistencia al flujo de muestras del material bajo estudio. Las ecuaciones que gobiernan el comportamiento desde el punto de vista acústico del material se obtienen a partir del ajuste de ecuaciones de comportamiento de la impedancia acústica y la constante de propagación del material. Los resultados son útiles ya que, al disponer de ecuaciones analíticas obtenidas empíricamente, facilitan la incorporación de estos materiales en predicciones mediante métodos numéricos del comportamiento cuando son instalados formando parte de dispositivos para el control del ruido.

  5. Prediction of microwave absorption properties of tetrapod-needle zinc oxide whisker radar absorbing material without prior knowledge

    Science.gov (United States)

    Zhao, Yu-Chen; Wang, Jie; Liu, Jiang-Fan; Song, Zhong-Guo; Xi, Xiao-Li

    2017-07-01

    The radar absorbing material (RAM) containing a tetrapod-needle zinc oxide whisker (T-ZnOw) has been proved to have good efficiency of microwave absorption. However, the available theoretical models, which are intended to predict the microwave absorbing properties of such an interesting composite, still cannot work well without some prior knowledge, like the measured effective electromagnetic parameters of the prepared T-ZnOw composite. Hence, we propose a novel predictive method here to calculate the reflectivity of T-ZnOw RAM without prior knowledge. In this method, the absorbing ability of this kind of material is divided into three main aspects: the unstructured background, the conductive network, and the nanostructured particle. Then, the attenuation properties of these three parts are represented, respectively, by three different approaches: the equivalent spherical particle and the static strong fluctuation theory, the equivalent circuit model obtained from the complex impedance spectra technology, and the combination of four different microscopic electromagnetic responses. The operational calculation scheme can be obtained by integrating these three absorption effects into the existing theoretical attenuation model. The reasonable agreement between the theoretical and experimental data of a T-ZnON/SiO2 composite in the range of 8-14 GHz shows that the proposed scheme can predict the microwave absorption properties of the T-ZnOw RAM. Furthermore, a detailed analysis of these three mechanisms indicates that, on the one hand, the background plays a dominant role in determining the real part of the effective permittivity of the T-ZnOw composite while the network and the particle are the decisive factors of its material loss; on the other hand, an zero-phase impedance, i.e., a pure resistance, with appropriate resonance characteristic might be a rational physical description of the attenuation property of the conductive network, but it is difficult to realize

  6. Study of the relationship between peaks scattering Rayleigh to Compton ratio and effective atomic number in biological samples

    International Nuclear Information System (INIS)

    Pereira, Marcelo O.; Conti, Claudio de Carvalho; Anjos, Marcelino J.; Lopes, Ricardo T.

    2011-01-01

    The aim of this work was to develop a new method to correct the absorbed radiation (the mass attenuation coefficient curve) in low energy (E B O 3 , Na 2 CO 3 , CaCO 3 , Al 2 O 3 , K 2 SO 4 and MgO) of radiation produced by a gamma-ray source of Am-241(59.54 keV) also applied to certified biological samples of milk powder, hay powder and bovine liver (NIST 155 7B). In addition, six methods of effective atomic number determination were used as described in literature to determinate the Rayleigh to Compton scattering ratio (R/C) , in order to calculate the mass attenuation coefficient. The results obtained by the proposed method were compared with those obtained using the transmission method. The experimental results were in good agreement with transmission values suggesting that the method to correct radiation absorption presented in this paper is adequate for biological samples. (author)

  7. Enhanced Electromagnetic and Chemical/Biological Sensing. Properties of Atomic Cluster-Derived Materials

    National Research Council Canada - National Science Library

    Schatz, George

    2003-01-01

    The Center for Atomic Clusters-derived Materials performed a broad range of research concerned with synthesizing, characterizing and utilizing atomic and molecular clusters, nanoparticles and nanomaterial...

  8. Displacement per atom profile in carbon nanotube bulk material under gamma irradiation

    International Nuclear Information System (INIS)

    Leyva, A.; Pinnera, I.; Leyva, D.; Cruz, C.; Abreu, Y.

    2011-01-01

    Taking into account the physical properties and the displacement threshold energy values reported in literature for C atoms in single and multiple walled carbon nanotubes, the effective atomic displacement cross-section in carbon nanotube bulk materials exposed to the gamma rays were calculated. Then, using the mathematical simulation of photons and particles transport in the matter, energy fluxes distribution of electrons and positrons within the irradiated object were also calculated. Finally, considering both results, the atomic displacement damage profiles inside the analyzed carbon nanotube bulk materials were determined. (Author)

  9. Electron and positron contributions to the displacement per atom profile in bulk multi-walled carbon nanotube material irradiated with gamma rays

    International Nuclear Information System (INIS)

    Leyva Fabelo, Antonio; Pinnera Hernandez, Ibrahin; Leyva Pernia, Diana

    2013-01-01

    The electron and positron contributions to the effective atom displacement cross-section in multi-walled carbon nanotube bulk materials exposed to gamma rays were calculated. The physical properties and the displacement threshold energy value reported in literature for this material were taken into account. Then, using the mathematical simulation of photon and particle transport in matter, the electron and positron energy flux distributions within the irradiated object were also calculated. Finally, considering both results, the atom displacement damage profiles inside the analyzed bulk carbon nanotube material were determined. The individual contribution from each type of secondary particles generated by the photon interactions was specified. An increasing behavior of the displacement cross-sections for all the studied particles energy range was observed. The particles minimum kinetic energy values that make probabilistically possible the single and multiple atom displacement processes were determined. The positrons contribution importance to the total number of point defects generated during the interaction of gamma rays with the studied materials was confirmed

  10. Atomic bomb injury: radiation

    Energy Technology Data Exchange (ETDEWEB)

    Dunham, C L; Cronkite, E P; Le Roy, G V; Warren, S

    1959-01-01

    This document contains 3 reports. In the first report, the clinical diagnosis and treatment of radiation syndrome in survivors of the atomic explosions in Hiroshima and Nagasaki are described. The syndrome of acute radiation injury is applied to the symptom complex, or diseased state, which results from exposure of the whole body to the initial nuclear radiation of an atomic bomb. It is applied to injuries of the skin and subcutaneous tissues resulting from x-radiation or from contact with radioactive material. Internal radiation injury may result from the selective deposition, such as in bone or thyroid, of radioactive material that has been inhaled or absorbed through the gastrointestinal tract or wounds. Radiation syndrome is classified as very severe, severe, and mild. In the second report, a brief discussion is presented on the question of genetic effects in atomic bomb survivors in Hiroshima and Nagasaki. In the third report, a study was carried out on 205 4-1/2 year old children who had been exposed to the atomic bomb blast during the first half of intra-uterine life. Correlation between head size and mental development of the child with distance from the hypocenter, symptoms of radiation effect and type of shielding of the mother is discussed. The conclusion drawn from the present study is that central nervous system defects can be produced in the fetus by atomic bomb radiation, provided that exposure occurs within approximately 1200 meters of the hypocenter and that no effective shielding, such as concrete, protects the fetus from direct irradiation.

  11. Thin and Broadband Two-Layer Microwave Absorber in 4-12 GHz with Developed Flaky Cobalt Material

    Science.gov (United States)

    Gill, Neeraj; Singh, Jaydeep; Puthucheri, Smitha; Singh, Dharmendra

    2018-03-01

    Microwave absorbing materials (MAMs) in the frequency range of 2.0-18.0 GHz are essential for the stealth and communication applications. Researchers came up with effective MAMs for the higher frequency regions, i.e., 8.0-18.0 GHz, while absorbers with comparable properties in the lower frequency band are still not in the limelight. Designing a MAM for the lower frequency range is a critical task. It is known that the factors governing the absorption in this frequency predominantly depend on the permeability and conductivity of the material, whereas the shape anisotropy of the particles can initiate different absorption mechanisms like multiple internal reflections, phase cancellations, surface charge polarization and enhanced conductivity that can promote the microwave absorption towards lower frequencies. But the material alone may not serve the purpose of getting broad absorption bandwidth. With the effective use of advanced electromagnetic technique like multi-layering this problem may be solved. Therefore, in this paper, a material with shape anisotropy (cobalt flakes with high shape anisotropy) has been prepared and a two-layer structure is developed which gives the absorption bandwidth in 4.17-12.05 GHz at a coating thickness of 2.66 mm.

  12. The method of intersecting spheres for determination of coordination numbers of atoms in crystal structures

    International Nuclear Information System (INIS)

    Serezhkin, V.N.; Buslaev, Yu.A.; Mikhajlov, Yu.N.

    1997-01-01

    New method for determination of coordination numbers (CN) of atoms in crystal structures, based on the model of interatomic interaction, within the frames whereof each atom is approximated by two spheres with the common center in the atom nuclei, is proposed. One of the spheres specifies conditionally isolated (chemically unbound) atom and its radius is a constant, which for atoms of the given chemical sort in the structure of any compound is equal to quasi-orbital Sleiter radius. The sphere of the other radius specifies chemically bound atom and coincides with the sphere, the volume whereof is equal to the volume of the Voronoj-Dirichlet polyhedron of the corresponding atom in the structure of the concrete crystal. Using a series of examples, workability of the given method for CN determination of atoms in structures of both simple substances and chemical compounds (alkali, transition metals, U, Th). Good agreement of the obtained results with the generally accepted CN s of atoms for the considered crystals is noted and a number of principal advantages of the new method, as compared to classical one of the CNs evaluation, is demonstrated

  13. EM wave propagation analysis in plasma covered radar absorbing material

    CERN Document Server

    Singh, Hema; Rawat, Harish Singh

    2017-01-01

    This book focuses on EM propagation characteristics within multilayered plasma-dielectric-metallic media. The method used for analysis is impedance transformation method. Plasma covered radar absorbing material is approximated as a multi-layered dielectric medium. The plasma is considered to be bounded homogeneous/inhomogeneous medium. The reflection coefficient and hence return loss is analytically derived. The role of plasma parameters, such as electron density, collision frequency, plasma thickness, and plasma density profile in the absorption behavior of multi-layered plasma-RAM structure is described. This book provides a clearer picture of EM propagation within plasma. The reader will get an insight of plasma parameters that play significant role in deciding the absorption characteristics of plasma covered surfaces.

  14. Atomic and plasma-material interaction data for fusion. V. 6

    International Nuclear Information System (INIS)

    1995-01-01

    Volume 6 of the supplement ''atomic and plasma-material interaction data for fusion'' to the journal ''Nuclear Fusion'' includes critical assessments and results of original experimental and theoretical studies on inelastic collision processes among the basic and dominant impurity constituents of fusion plasmas. Processes considered in the 15 papers constituting this volume are: electron impact excitation of excited Helium atoms, electron impact excitation and ionization of plasma impurity ions and atoms, electron-impurity-ion recombination and excitation, ionization and electron capture in collisions of plasma protons and impurity ions with the main fusion plasma neutral components helium and atomic and molecular hydrogen. Refs, figs, tabs

  15. Analytical dependence of effective atomic number on the elemental composition of matter and radiation energy in the range 10-1000 keV

    Science.gov (United States)

    Eritenko, A. N.; Tsvetiansky, A. L.; Polev, A. A.

    2018-01-01

    In the present paper, a universal analytical dependence of effective atomic number on the composition of matter and radiation energy is proposed. This enables one to consider the case of a strong difference in the elemental composition with respect to their atomic numbers over a wide energy range. The contribution of photoelectric absorption and incoherent and coherent scattering during the interaction between radiation and matter is considered. For energy values over 40 keV, the contribution of coherent scattering does not exceed approximately 10% that can be neglected at a further consideration. The effective atomic numbers calculated on the basis of the proposed relationships are compared to the results of calculations based on other methods considered by different authors on the basis of experimental and tabulated data on mass and atomic attenuation coefficients. The examination is carried out for both single-element (e.g., 6C, 14Si, 28Cu, 56Ba, and 82Pb) and multi-element materials. Calculations are performed for W1-xCux alloys (x = 0.35; x = 0.4), PbO, ther moluminescent dosimetry compounds (56Ba, 48Cd, 41Sr, 20Ca, 12Mg, and 11Na), and SO4 in a wide energy range. A case with radiation energy between the K- and L1-absorption edges is considered for 82Pb, 74W, 56Ba, 48Cd, and 38Sr. This enables to substantially simplify the calculation of the atomic number and will be useful in technical and scientific fields related to the interaction between X-ray/gamma radiation and matter.

  16. Material for 258 atom bombs disappeared?

    International Nuclear Information System (INIS)

    Gruemm, H.

    1988-01-01

    In a report published in the news magazine, 'Der Spiegel', it was said that IAEA safeguards obviously had failed, for large amounts of fissile material had disappeared, which could be turned into 258 atomic bombs. The article in this issue of atw by the former Deputy Director General with the IAEA Safeguards Division sketches the background to the assertions made by 'Der Spiegel' and presents an overview of the inspection and verification methods employed by IAEA. (orig./HP) [de

  17. Two-Dimensional SnO Anodes with a Tunable Number of Atomic Layers for Sodium Ion Batteries

    KAUST Repository

    Zhang, Fan; Zhu, Jiajie; Zhang, Daliang; Schwingenschlö gl, Udo; Alshareef, Husam N.

    2017-01-01

    We have systematically changed the number of atomic layers stacked in 2D SnO nanosheet anodes and studied their sodium ion battery (SIB) performance. The results indicate that as the number of atomic SnO layers in a sheet decreases, both

  18. Casimir interaction between gas media of excited atoms

    International Nuclear Information System (INIS)

    Sherkunov, Yury

    2007-01-01

    The retarded dispersion interaction (Casimir interaction) between two dilute dielectric media at high temperatures is considered. The excited atoms are taken into account. It is shown that the perturbation technique cannot be applied to this problem due to divergence of integrals. A non-perturbative approach based on kinetic Green functions is implemented. We consider the interaction between two atoms (one of them is excited) embedded in an absorbing dielectric medium. We take into account the possible absorption of photons in the medium, which solves the problem of divergence. The force between two plane dilute dielectric media is calculated at pair interaction approximation. We show that the result of quantum electrodynamics differs from the Lifshitz formula for dilute gas media at high temperatures (if the number of excited atoms is significant). According to quantum electrodynamics, the interaction may be either attractive or repulsive depending on the temperature and the density numbers of the media

  19. Carbon nanotube scaffolds with controlled porosity as electromagnetic absorbing materials in the gigahertz range

    Science.gov (United States)

    González, M.; Crespo, M.; Baselga, J.; Pozuelo, J.

    2016-05-01

    Control of the microscopic structure of CNT nanocomposites allows modulation of the electromagnetic shielding in the gigahertz range. The porosity of CNT scaffolds has been controlled by two freezing protocols and a subsequent lyophilization step: fast freezing in liquid nitrogen and slow freezing at -20 °C. Mercury porosimetry shows that slowly frozen specimens present a more open pore size (100-150 μm) with a narrow distribution whereas specimens frozen rapidly show a smaller pore size and a heterogeneous distribution. 3D-scaffolds containing 3, 4, 6 and 7% CNT were infiltrated with epoxy and specimens with 2, 5 and 8 mm thicknesses were characterized in the GHz range. Samples with the highest pore size and porosity presented the lowest reflected power (about 30%) and the highest absorbed power (about 70%), which allows considering them as electromagnetic radiation absorbing materials.Control of the microscopic structure of CNT nanocomposites allows modulation of the electromagnetic shielding in the gigahertz range. The porosity of CNT scaffolds has been controlled by two freezing protocols and a subsequent lyophilization step: fast freezing in liquid nitrogen and slow freezing at -20 °C. Mercury porosimetry shows that slowly frozen specimens present a more open pore size (100-150 μm) with a narrow distribution whereas specimens frozen rapidly show a smaller pore size and a heterogeneous distribution. 3D-scaffolds containing 3, 4, 6 and 7% CNT were infiltrated with epoxy and specimens with 2, 5 and 8 mm thicknesses were characterized in the GHz range. Samples with the highest pore size and porosity presented the lowest reflected power (about 30%) and the highest absorbed power (about 70%), which allows considering them as electromagnetic radiation absorbing materials. Electronic supplementary information (ESI) available: Scheme of hydrogenated derivative of diglycidyl ether of bisphenol-A (HDGEBA) and m-xylylenediamine; X-ray diffractograms of pristine CNT

  20. An experimental study of an energy absorbing restrainer for piping systems

    International Nuclear Information System (INIS)

    Sone, A.; Suzuki, K.

    1989-01-01

    Recently, in the seismic design methodology of the piping systems in nuclear power plants, new and improved design criteria and calculation techniques which will lead to more reliable and cost saving design products have been investigated. For instance, problems for reducing the snubbers in nuclear power plants which provide high costs for their inspections and maintenances and related flexible design problems for the dynamic piping systems have been investigated. Thus, in order to replace snubbers, various types of alternative supporting devices such as dynamic absorbers, gapped support and energy absorbing support devices have been proposed. A number of energy absorbing restrainers have been designed in Japan and United-States by allowing yield to occur during strong earthquakes. Advantages and disadvantages of these restrainers were examined analytically and experimentally. In order to overcome the disadvantages, the authors introduced new absorbing material LSPZ (laminated super plastic zinc) in which SPZ is expected to have reliable ductility and also efficient energy absorbability still under the normal temperature condition. This paper is devoted to an experimental works for this updated absorbing restrainer

  1. Determination of atomic number and composition of human enamel; Determinacao da composicao e numero atomico efetivo do esmalte humano

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira, M.S. [Centro Regional de Ciencias Nucleares (CRCN), Recife, PE (Brazil); Rodas Duran, J.E. [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Filosofia, Ciencias e Letras. Dept. de Fisica e Matematica

    2001-07-01

    The teeth are organs of complicated structure that consist, partly, of hard tissue containing in its interior the dental pulp, rich in vases and nerves. The main mass of the tooth is constituted by the dentine, which is covered with hard tissues and of epithelial origin called enamel. The dentine of the human teeth used in this work were completely removed and the teeth were cut with a device with a diamond disc. In this work the chemical composition of the human enamel was determined, which showed a high percentage of Ca and P, in agreement with the results found in the literature. The effective atomic number of the material and the half-value layer in the energy range of diagnostic X-ray beams were determined. Teeth could be used to evaluated the public's individual doses as well as for retrospective dosimetry what confirms the importance of their effective atomic number and composition determination. (author)

  2. Solar-absorbing metamaterial microencapsulation of phase change materials for thermo-regulating textiles

    Directory of Open Access Journals (Sweden)

    William Tong

    2015-04-01

    Full Text Available This paper presents a novel concept for designing solar-absorbing metamaterial microcapsules of phase change materials (PCMs integrated with thermo-regulating smart textiles intended for coats or garments, especially for wear in space or cold weather on earth. The metamaterial is a periodically nanostructured metal-dielectric-metal thin film and can acquire surface plasmons to trap or absorb solar energy at subwavelength scales. This kind of metamaterial microencapsulation is not only able to take advantage of latent heat that can be stored or released from the PCMs over a tunable temperature range, but also has other advantages over conventional polymer microencapsulation of PCMs, such as enhanced thermal conductivity, improved flame-retardant capabilities, and usage as an extra solar power resource. The thermal analysis for this kind of microencapsulation has been done and can be used as a guideline for designing integrated thermo-regulating smart textiles in the future. These metamaterial microcapsules may open up new routes to enhancing thermo-regulating textiles with novel properties and added value.

  3. The Australian Commonwealth standard of measurement for absorbed radiation dose

    International Nuclear Information System (INIS)

    Sherlock, S.L.

    1990-06-01

    This report documents the absorbed dose standard for photon beams in the range from 1 to 25 MeV. Measurements of absorbed dose in graphite irradiated by a beam of cobalt-60 gamma rays from an Atomic Energy of Canada Limited (AECL) E1 Dorado 6 teletherapy unit are reported. The measurements were performed using a graphite calorimeter, which is the primary standard for absorbed dose. The measurements are used to calibrate a working standard ion chamber in terms of absorbed dose in graphite. Details of the methods, results and correction factors applied are given in Appendices. 13 refs., 6 tabs., 6 figs

  4. Science and Emerging Technology of 2D Atomic Layered Materials and Devices

    Science.gov (United States)

    2017-09-09

    AFRL-AFOSR-JP-TR-2017-0067 Science & Emerging Technology of 2D Atomic Layered Materials and Devices Angel Rubio UNIVERSIDAD DEL PAIS VASCO - EUSKAL...DD-MM-YYYY)      27-09-2017 2.  REPORT TYPE      Final 3.  DATES COVERED (From - To)      19 Feb 2015 to 18 Feb 2017 4.  TITLE AND SUBTITLE Science ...reporting documents for AOARD project 144088, “2D Materials and Devices Beyond Graphene Science & Emerging Technology of 2D Atomic Layered Materials and

  5. Tailoring of materials by atomic oxygen from ECR plasma source

    International Nuclear Information System (INIS)

    Naddaf, Munzer; Bhoraskar, S.V.

    2002-01-01

    Full text: An intense source of oxygen finds important applications in many areas of science, technology and industry. It has been successfully used for surface activation and cleaning in the electronic, chemical and automotive industries. Atomic oxygen and interaction with materials have also a significant importance in space science and technology. This paper describes the detailed studies related to the surface modification and processing of different materials, which include metals and polymers by atomic oxygen produced in microwave assisted electron cyclotron resonance plasma. The energy distribution of ions was measured as a function of plasma parameters and density measurements were supplemented by catalytic probe using nickel and oxidation of silver surface

  6. Radio-isotopic apparatus for analyzing low atomic number elements by fluorescence

    International Nuclear Information System (INIS)

    Robert, Andre; Martinelli, Pierre; Daniel, Georges; Laflotte, Jean-Luc

    1969-10-01

    An apparatus is described for analyzing light elements of atomic number between 6 and 24 by X-fluorescence. The samples are excited by means of X or α isotopic sources. Various examples of analytical determinations are given. (author) [fr

  7. Current Trends in Atomic Spectroscopy.

    Science.gov (United States)

    Wynne, James J.

    1983-01-01

    Atomic spectroscopy is the study of atoms/ions through their interaction with electromagnetic radiation, in particular, interactions in which radiation is absorbed or emitted with an internal rearrangement of the atom's electrons. Discusses nature of this field, its status and future, and how it is applied to other areas of physics. (JN)

  8. Organ dose estimates for the Japanese atomic-bomb survivors

    International Nuclear Information System (INIS)

    Kerr, G.D.

    1978-10-01

    Recent studies concerning radiation risks to man by the Committee on Biological Effects of Ionizing Radiation of the National Academy of Sciences-National Research Council and the United Nations Scientific Committee on the Effects of Atomic Radiation have emphasized the need for estimates of dose to organs of the Japanese atomic-bomb survivors. Shielding of internal organs by the body has been investigated for fission-weapon gamma rays and neutrons, and ratios of mean absorbed dose in a number of organs to survivors' T65D assignments of tissue kerma in air are provided for adults. Ratios of mean absorbed dose to tissue kerma in air are provided also for the thyroid and active bone marrow of juveniles. These organ dose estimates for juveniles are of interest in studies of radiation risks due to an elevated incidence of leukemia and thyroid cancer in survivors exposed as children compared to survivors exposed as adults

  9. Nonlinear Ballistic Transport in an Atomically Thin Material.

    Science.gov (United States)

    Boland, Mathias J; Sundararajan, Abhishek; Farrokhi, M Javad; Strachan, Douglas R

    2016-01-26

    Ultrashort devices that incorporate atomically thin components have the potential to be the smallest electronics. Such extremely scaled atomically thin devices are expected to show ballistic nonlinear behavior that could make them tremendously useful for ultrafast applications. While nonlinear diffusive electron transport has been widely reported, clear evidence for intrinsic nonlinear ballistic transport in the growing array of atomically thin conductors has so far been elusive. Here we report nonlinear electron transport of an ultrashort single-layer graphene channel that shows quantitative agreement with intrinsic ballistic transport. This behavior is shown to be distinctly different than that observed in similarly prepared ultrashort devices consisting, instead, of bilayer graphene channels. These results suggest that the addition of only one extra layer of an atomically thin material can make a significant impact on the nonlinear ballistic behavior of ultrashort devices, which is possibly due to the very different chiral tunneling of their charge carriers. The fact that we observe the nonlinear ballistic response at room temperature, with zero applied magnetic field, in non-ultrahigh vacuum conditions and directly on a readily accessible oxide substrate makes the nanogap technology we utilize of great potential for achieving extremely scaled high-speed atomically thin devices.

  10. Magnetism of a relaxed single atom vacancy in graphene

    Science.gov (United States)

    Wu, Yunyi; Hu, Yonghong; Xue, Li; Sun, Tieyu; Wang, Yu

    2018-04-01

    It has been suggested in literature that defects in graphene (e.g. absorbed atoms and vacancies) may induce magnetizations due to unpaired electrons. The nature of magnetism, i.e. ferromagnetic or anti-ferromagnetic, is dependent on a number of structural factors including locations of magnetic moments and lattice symmetry. In the present work we investigated the influence of a relaxed single atom vacancy in garphnene on magnetization which were obtained under different pinning boundary conditions, aiming to achieve a better understanding of the magnetic behaviors of graphene. Through first principles calculations, we found that major spin polarizations occur on atoms that deviate slightly from their original lattice positions, and pinning boundaries could also affect the relaxed positions of atoms and determine which atom(s) would become the main source(s) of total spin polarizations and magnetic moments. When the pinning boundary condition is free, a special non-magnetic and semi-conductive structure may be obtained, suggesting that magnetization should more readily occur under pinning boundary conditions.

  11. New absorbent acoustic materials from plastic bottle remnants

    Directory of Open Access Journals (Sweden)

    del Rey, R.

    2011-12-01

    Full Text Available In the building acoustics field usually fibrous materials are used as sound absorbing materials. Nowadays polyester fiber is one of the most used but the pure chip of polyester has a problem. Polyester is obtained of petroleum and its price was increasing last years. This paper, presents an alternative polyester wool which obtained by PET treatment (recycle of plastic bottle’s. Absorption coefficient values at normal incidence measured in reverberation chamber were compared (new wool obtained by PET method and materials obtained from pure chip of polyester.Furthermore, this paper propound a empiric model that describe the acoustic performance of this new wool. The results have been good. The pure fiber has been replaced by recycle fiber in its manufacture process.

    En el ámbito de acústica de la edificación es común el uso de materiales fibrosos como materiales absorbentes acústicos. Uno de estos materiales cada vez más utilizado es la lana de poliéster. Un problema que presenta el chip virgen de poliéster es que se obtiene del petróleo, cuyo precio no hace más que incrementarse en los últimos años. En este trabajo se presenta una lana de poliéster alternativa, obtenida mediante el tratamiento del PET, a través del conveniente ciclo de reciclado de botellas de plástico. Se comparan valores del coeficiente de absorción; en incidencia normal y en cámara reverberante de los materiales elaborados a partir de chip virgen y de las nuevas lanas obtenidas del PET. Además, se propone un modelo empírico de comportamiento acústico de estas nuevas lanas. Los resultados obtenidos han sido favorables, la fibra virgen ya ha sido sustituida por fibra reciclada en su proceso de fabricación.

  12. Unraveling atomic-level self-organization at the plasma-material interface

    Science.gov (United States)

    Allain, J. P.; Shetty, A.

    2017-07-01

    The intrinsic dynamic interactions at the plasma-material interface and critical role of irradiation-driven mechanisms at the atomic scale during exposure to energetic particles require a priori the use of in situ surface characterization techniques. Characterization of ‘active’ surfaces during modification at atomic-scale levels is becoming more important as advances in processing modalities are limited by an understanding of the behavior of these surfaces under realistic environmental conditions. Self-organization from exposure to non-equilibrium and thermalized plasmas enable dramatic control of surface morphology, topography, composition, chemistry and structure yielding the ability to tune material properties with an unprecedented level of control. Deciphering self-organization mechanisms of nanoscale morphology (e.g. nanodots, ripples) and composition on a variety of materials including: compound semiconductors, semiconductors, ceramics, polymers and polycrystalline metals via low-energy ion-beam assisted plasma irradiation are critical to manipulate functionality in nanostructured systems. By operating at ultra-low energies near the damage threshold, irradiation-driven defect engineering can be optimized and surface-driven mechanisms controlled. Tunability of optical, electronic, magnetic and bioactive properties is realized by reaching metastable phases controlled by atomic-scale irradiation-driven mechanisms elucidated by novel in situ diagnosis coupled to atomistic-level computational tools. Emphasis will be made on tailored surface modification from plasma-enhanced environments on particle-surface interactions and their subsequent modification of hard and soft matter interfaces. In this review, we examine current trends towards in situ and in operando surface and sub-surface characterization to unravel atomic-scale mechanisms at the plasma-material interface. This work will emphasize on recent advances in the field of plasma and ion

  13. Radiation sterilization of absorbent cotton and of absorbent gauze

    International Nuclear Information System (INIS)

    Hosobuchi, Kazunari; Oka, Mitsuru; Kaneko, Akira; Ishiwata, Hiroshi.

    1986-01-01

    The bioburden of absorbent cotton and of absorbent gauze and their physical and chemical characteristics after irradiation are investigated. The survey conducted on contaminants of 1890 cotton samples from 53 lots and 805 gauze samples from 56 lots showed maximum numbers of microbes per g of the cotton and gauze were 859 (an average of 21.4) and 777 (an average of 42.2), respectively. Isolation and microbiological and biochemical tests of representative microbes indicated that all of them, except one, were bacilli. The sterilization dose at 10 -6 of sterlity assurance level was found to be 2.0 Mrad when irradiated the spores loaded on paper strips and examined populations having graded D values from 0.10 to 0.28 Mrad. The sterilization dose would be about 1.5 Mrad if subjected the average numbers of contaminants observed in this study to irradiation. No significant differences were found between the irradiated samples and control up to 2 Mrad in tensile strength, change of color, absorbency, sedimentation rate, soluble substances, and pH of solutions used for immersion and other tests conventionally used. These results indicate that these products can be sterilized by irradiation. (author)

  14. An improved method for the determination of trace levels of arsenic and antimony in geological materials by automated hydride generation-atomic absorption spectroscopy

    Science.gov (United States)

    Crock, J.G.; Lichte, F.E.

    1982-01-01

    An improved, automated method for the determination of arsenic and antimony in geological materials is described. After digestion of the material in sulfuric, nitric, hydrofluoric and perchloric acids, a hydrochloric acid solution of the sample is automatically mixed with reducing agents, acidified with additional hydrochloric acid, and treated with a sodium tetrahydroborate solution to form arsine and stibine. The hydrides are decomposed in a heated quartz tube in the optical path of an atomic absorption spectrometer. The absorbance peak height for arsenic or antimony is measured. Interferences that exist are minimized to the point where most geological materials including coals, soils, coal ashes, rocks and sediments can be analyzed directly without use of standard additions. The relative standard deviation of the digestion and the instrumental procedure is less than 2% at the 50 ??g l-1 As or Sb level. The reagent-blank detection limit is 0.2 ??g l-1 As or Sb. ?? 1982.

  15. Development of a standard data base for FBR core nuclear design. 10. Reevaluation of atomic number density of JOYO Mk-II core

    Energy Technology Data Exchange (ETDEWEB)

    Numata, Kazuyuki; Sato, Wakaei [Japan Nuclear Cycle Development Inst., Oarai, Ibaraki (Japan). Oarai Engineering Center; Ishikawa, Makoto; Arii, Yoshio [Nuclear Energy System Incorporation, Tokyo (Japan)

    1999-07-01

    The material composition of JOYO Mk-II core components in its initial core was reevaluated as a part of the effort for developing a standard data base for FBR core nuclear design. The special feature of the reevaluation is to treat the decay of Pu-241 isotope, so that the atomic number densities of Pu-241 and Am-241 in fuel assemblies can be exactly evaluated on the initial critical date, Nov. 22nd, 1982. Further, the atomic number densities of other core components were also evaluated to improve the analytical accuracy. Those include the control rods which were not so strictly evaluated in the past, and the dummy fuels and the neutron sources which were not treated in the analytical model so far. The results of the present reevaluation were as follows: (1) The changes of atomic number densities of the major nuclides such as Pu-239, U-235 and U-238 were about {+-}0.2 to 0.3%. On the other hand, the number density of Pu-241, which was the motivation of the present work, was reduced by 12%. From the fact, the number densities in the past analysis might be based on the isotope measurement of the manufacturing point of time without considering the decay of Pu-241. (2) As the other core components, the number densities of control rods and outer reflector-type A were largely improved. (author)

  16. Recent developments of smart electromagnetic absorbers based polymer-composites at gigahertz frequencies

    International Nuclear Information System (INIS)

    Idris, Fadzidah Mohd.; Hashim, Mansor; Abbas, Zulkifly; Ismail, Ismayadi; Nazlan, Rodziah; Ibrahim, Idza Riati

    2016-01-01

    The rapid increase in electromagnetic interference has received a serious attention from researchers who responded by producing a variety of radar absorbing materials especially at high gigahertz frequencies. Ongoing investigation is being carried out in order to find the best absorbing materials which can fulfill the requirements for smart absorbing materials which are lightweight, broad bandwidth absorption, stronger absorption etc. Thus, to improve the absorbing capability, several important parameters need to be taken into consideration such as filler type, loading level, type of polymer matrix, physical thickness, grain sizes, layers and bandwidth. Therefore, this article introduces the electromagnetic wave absorption mechanisms and then reveals and reviews those parameters that enhance the absorption performance. - Highlights: • Development variety of radar absorbing materials especially at high gigahertz frequencies. • Best absorbing materials which can fulfill the requirements for smart absorbing materials which are lightweight, broad bandwidth absorption, stronger absorption etc. • Important parameters need to be taken into consideration to obtain stronger absorption and better performances.

  17. Comparison of effective atomic numbers of the cancerous and normal kidney tissue

    International Nuclear Information System (INIS)

    Manjunatha, H.C.

    2015-01-01

    The effective atomic number (Z eff ) and electron density (N e ) of normal kidney and cancerous kidney have been computed for total and partial photon interactions by computing the molecular, atomic, and electronic cross section in the wide energy range of 1 keV-100 GeV using WinXCOM. The mean Z eff and N e of normal kidney and cancerous kidney in the various energy ranges and for total and partial photon interactions are tabulated. The variation of effective N e with energy is shown graphically for all photon interactions. In addition to this computer tomography (CT), numbers of normal kidney and cancerous kidney for photon interaction and energy absorption is also computed. The role of Z eff in the dual-energy dividing radiography is also discussed. The values of Z eff and N e for cancerous kidney are higher than normal kidney. This is due to the levels of elements K, Ca, Fe, Ni, and Se are lower and those of the elements Ti, Co, Zn, As, and Cd are higher in the cancer tissue of kidney than those observed in the normal tissue. The soft tissue and cancerous tissue are very similar, but their atomic number differs. The cancerous tissue exhibits a higher Z eff than the normal tissue. This fact helps in the dual-energy dividing radiography which enables to improve the diagnosis of the kidney cancer. Hence, the computed values may be useful in the diagnosis of the kidney cancer. CT numbers for normal kidney are higher than cancerous kidney. (author)

  18. Effective atomic number and electron density of marble concrete

    International Nuclear Information System (INIS)

    Akkurt, I.; El-Khayatt, A.M.

    2013-01-01

    The effective atomic numbers (Z eff ) and effective electron density (N e ) of different type concrete have been measured and the results were compared with the calculation obtained using the mass attenuation coefficients (μ/ρ) obtained via XCOM in the photon energy range of 1 keV-100 GeV. Six different concrete in where marble has been used in the rate of 0, 5, 10, 15, 20, 25 %, has been used in the study. (author)

  19. Successive change regularity of actinide properties with atomic number

    International Nuclear Information System (INIS)

    Yang Xuexian

    1990-08-01

    The development and achievements on chemistry of actinide elements are summarised. The relations of properties of actinides to their electronic configurations of valence electronic shells are discussed. Some anomalies of solid properties, the radius contraction, the stable state effect of f 7n -orbits (n = 0, 1, 2) and the tetrad effect of oxidation states, etc., with atomic number (Z) are described. 31 figures appended show directly the successive change regularity of actinide properties with Z

  20. [Measurement of atomic number of alkali vapor and pressure of buffer gas based on atomic absorption].

    Science.gov (United States)

    Zheng, Hui-jie; Quan, Wei; Liu, Xiang; Chen, Yao; Lu, Ji-xi

    2015-02-01

    High sensitivitymagnetic measurementscanbe achieved by utilizing atomic spinmanipulation in the spin-exchange-relaxation-free (SERF) regime, which uses an alkali cell as a sensing element. The atomic number density of the alkali vapor and the pressure of the buffer gasare among the most important parameters of the cell andrequire accurate measurement. A method has been proposed and developedto measure the atomic number density and the pressure based on absorption spectroscopy, by sweeping the absorption line and fittingthe experiment data with a Lorentzian profile to obtainboth parameters. Due to Doppler broadening and pressure broadening, which is mainly dominated by the temperature of the cell and the pressure of buffer gas respectively, this work demonstrates a simulation of the errorbetween the peaks of the Lorentzian profile and the Voigt profile caused by bothfactors. The results indicates that the Doppler broadening contribution is insignificant with an error less than 0.015% at 313-513 K for a 4He density of 2 amg, and an error of 0.1% in the presence of 0.6-5 amg at 393 K. We conclude that the Doppler broadening could be ignored under above conditions, and that the Lorentzianprofile is suitably applied to fit the absorption spectrumobtainingboth parameters simultaneously. In addition we discuss the resolution and the instability due to thelight source, wavelength and the temperature of the cell. We find that the cell temperature, whose uncertainty is two orders of magnitude larger than the instability of the light source and the wavelength, is one of the main factors which contributes to the error.

  1. Ni-Al Alloys as Alternative EUV Mask Absorber

    Directory of Open Access Journals (Sweden)

    Vu Luong

    2018-03-01

    Full Text Available Extreme ultraviolet (EUV lithography is being industrialized as the next candidate printing technique for high-volume manufacturing of scaled down integrated circuits. At mask level, the combination of EUV light at oblique incidence, absorber thickness, and non-uniform mirror reflectance through incidence angle, creates photomask-induced imaging aberrations, known as mask 3D (M3D effects. A possible mitigation for the M3D effects in the EUV binary intensity mask (BIM, is to use mask absorber materials with high extinction coefficient κ and refractive coefficient n close to unity. We propose nickel aluminide alloys as a candidate BIM absorber material, and characterize them versus a set of specifications that a novel EUV mask absorber must meet. The nickel aluminide samples have reduced crystallinity as compared to metallic nickel, and form a passivating surface oxide layer in neutral solutions. Composition and density profile are investigated to estimate the optical constants, which are then validated with EUV reflectometry. An oxidation-induced Al L2 absorption edge shift is observed, which significantly impacts the value of n at 13.5 nm wavelength and moves it closer to unity. The measured optical constants are incorporated in an accurate mask model for rigorous simulations. The M3D imaging impact of the nickel aluminide alloy mask absorbers, which predict significant M3D reduction in comparison to reference absorber materials. In this paper, we present an extensive experimental methodology flow to evaluate candidate mask absorber materials.

  2. Regeneration performance of CO2-rich solvents by using membrane vacuum regeneration technology: Relationships between absorbent structure and regeneration efficiency

    International Nuclear Information System (INIS)

    Yan, Shuiping; Fang, Mengxiang; Wang, Zhen; Luo, Zhongyang

    2012-01-01

    Highlights: ► MVR may be viable to successfully use less valuable heat to replace high grade steam. ► Increasing OH and amine groups will increase the regeneration efficiency. ► Absorbents with a four carbon chain length will be more attractive to MVR. ► Amino acid salts will be more appropriate for MVR. ► HRM conducted at ambient pressure and low temperature is inferior to MVR. -- Abstract: In order to give a better understanding for the selection of suitable absorbents for the novel membrane vacuum regeneration technology (MVR) which has the potential to reduce CO 2 energy requirement by utilizing the waste heat or low-grade energy, an experimental study to determine the relationships between chemical structure and vacuum regeneration behavior of CO 2 absorbents at 70 °C and 10 kPa was performed. Eleven typical absorbents with different functional groups in their chemical structures were investigated in terms of vacuum regeneration efficiencies. Results showed that the regeneration efficiency decreased with an increase of number of activated hydrogen atom in amine group and decreased with the number of hydroxyl group. Especially, more attention should be paid to these alkanolamines with one hydrogen atom in amine group and two or more hydroxyl groups in the structures due to their better comprehensive performance in regeneration, absorbent loss and CO 2 absorption aspects. Increasing the carbon chain length and amine groups in the absorbent structure contributed to the improvement of regeneration performance and reduction of absorbent volatile loss. These absorbents with a four carbon chain length bonded at amine group might be more attractive to MVR. Furthermore, polyamines were superior to monoamines in terms of higher regeneration efficiencies and lower absorbent losses. Additionally, the individual effects of the potassium carboxylate group and hydroxymethylene group were also compared in this study. Results showed that amino acid salts were more

  3. Atomic and plasma-material interaction data for fusion. V. 2

    International Nuclear Information System (INIS)

    1992-01-01

    This issues of the Atomic and Plasma-Material Interaction Data for Fusion contains 9 papers on atomic and molecular processes in the edge region of magnetically confined fusion plasmas, including spectroscopic data for fusion edge plasmas; electron collision processes with plasma edge neutrals; electron-ion collisions in the plasma edge; cross-section data for collisions of electrons with hydrocarbon molecules; dissociative and energy transfer reactions involving vibrationally excited hydrogen or deuterium molecules; an assessment of ion-atom collision data for magnetic fusion plasma edge modeling; an extended scaling of cross sections for the ionization of atomic and molecular hydrogen as well as helium by multiply-charged ions; ion-molecule collision processes relevant to fusion edge plasmas; and radiative losses and electron cooling rates for carbon and oxygen plasma impurities. Refs, figs and tabs

  4. Fragmented metastable states exist in an attractive bose-einstein condensate for atom numbers well above the critical number of the Gross-Pitaevskii theory.

    Science.gov (United States)

    Cederbaum, Lorenz S; Streltsov, Alexej I; Alon, Ofir E

    2008-02-01

    It is well known that attractive condensates do not posses a stable ground state in three dimensions. The widely used Gross-Pitaevskii theory predicts the existence of metastable states up to some critical number N(cr)(GP) of atoms. It is demonstrated here that fragmented metastable states exist for atom numbers well above N(cr)(GP). The fragments are strongly overlapping in space. The results are obtained and analyzed analytically as well as numerically. The implications are discussed.

  5. A Two-Step Absorber Deposition Approach To Overcome Shunt Losses in Thin-Film Solar Cells: Using Tin Sulfide as a Proof-of-Concept Material System

    Energy Technology Data Exchange (ETDEWEB)

    Steinmann, Vera; Chakraborty, Rupak; Rekemeyer, Paul H.; Hartman, Katy; Brandt, Riley E.; Polizzotti, Alex; Yang, Chuanxi; Moriarty, Tom; Gradečak, Silvija; Gordon, Roy G.; Buonassisi, Tonio

    2016-08-31

    As novel absorber materials are developed and screened for their photovoltaic (PV) properties, the challenge remains to reproducibly test promising candidates for high-performing PV devices. Many early-stage devices are prone to device shunting due to pinholes in the absorber layer, producing 'false-negative' results. Here, we demonstrate a device engineering solution toward a robust device architecture, using a two-step absorber deposition approach. We use tin sulfide (SnS) as a test absorber material. The SnS bulk is processed at high temperature (400 degrees C) to stimulate grain growth, followed by a much thinner, low-temperature (200 degrees C) absorber deposition. At a lower process temperature, the thin absorber overlayer contains significantly smaller, densely packed grains, which are likely to provide a continuous coating and fill pinholes in the underlying absorber bulk. We compare this two-step approach to the more standard approach of using a semi-insulating buffer layer directly on top of the annealed absorber bulk, and we demonstrate a more than 3.5x superior shunt resistance Rsh with smaller standard error ..sigma..Rsh. Electron-beam-induced current (EBIC) measurements indicate a lower density of pinholes in the SnS absorber bulk when using the two-step absorber deposition approach. We correlate those findings to improvements in the device performance and device performance reproducibility.

  6. A study of energy and effective atomic number dependence of the exposure build-up factors in biological samples

    International Nuclear Information System (INIS)

    Sidhu, G.S.; Singh, P.S.; Mudahar, G.S.

    2000-01-01

    A theoretical method is presented to determine the gamma-radiation build-up factors in various biological materials. The gamma energy range is 0.015-15.0 MeV, with penetration depths up to 40 mean free paths considered. The dependence of the exposure build-up factor on incident photon energy and the effective atomic number (Z eff ) has also been assessed. In a practical analysis of dose burden to gamma-irradiated biological materials, the sophistication of Monte Carlo computer techniques would be applied, with associated detailed modelling. However, a feature of the theoretical method presented is its ability to make the consequences of the physics of the scattering process in biological materials more transparent. In addition, it can be quickly employed to give a first-pass dose estimate prior to a more detailed computer study. (author)

  7. Scanning tunneling spectroscopy on the chalcopyrite solar cell absorber material Cu(In,Ga)Se{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Moenig, Harry; Saez-Araoz, Rodrigo; Lux-Steiner, Martha [Freie Universitaet Berlin (Germany); Sadewasser, Sascha; Ennaoui, Ahmed; Kaufmann, Christian; Kropp, Timo; Lauermann, Iver; Muenchenberg, Tim; Schock, Hans-Werner; Streicher, Ferdinand [Hahn- Meitner-Institut Berlin (Germany)

    2007-07-01

    Cu(In,Ga)Se{sub 2}-based thin film solar cells have reached efficiencies close to 20%. Nevertheless, little is known about electronic transport and carrier recombination in this material on a microscopic scale. Especially grain boundaries in these polycrystalline materials are considered to play an important role in the performance of these solar cells. We applied scanning tunneling microscopy and spectroscopy to gain more insight in the electronic microstructure of the material. Our results point to lateral electronic inhomogeneities on the absorber surface and to an enhanced density of states at grain boundaries. The influence of charging effects is discussed.

  8. Competitive light absorbers in photoactive dental resin-based materials.

    Science.gov (United States)

    Hadis, Mohammed A; Shortall, Adrian C; Palin, William M

    2012-08-01

    The absorbance profile of photoinitiators prior to, during and following polymerization of light curable resin-based materials will have a significant effect on the cure and color properties of the final material. So-called "colorless" photoinitiators are used in some light-activated resin-based composite restorative materials to lessen the yellowing effect of camphoroquinone (CQ) in order to improve the esthetic quality of dental restorations. This work characterizes absorption properties of commonly used photoinitiators, an acylphosphine oxide (TPO) and CQ, and assesses their influence on material discoloration. Dimethacrylate resin formulations contained low (0.0134 mol/dm(3)), intermediate (0.0405 mol/dm(3)) or high (0.0678 mol/dm(3)) concentrations of the photoinitiators and the inhibitor, butylated hydroxytoluene (BHT) at 0, 0.1 or 0.2% by mass. Disc shaped specimens (n = 3) of each resin were polymerized for 60s using a halogen light curing unit. Dynamic measurements of photoinitiator absorption, polymer conversion and reaction temperature were performed. A spectrophotometer was used to measure the color change before and after cure. GLM three-way analysis of variance revealed significant differences (pphotoinitiator type (df = 1; F = 176.12)>% BHT (df = 2, F = 13.17). BHT concentration affected the rate of polymerization and produced lower conversion in some of the CQ-based resins. Significant differences between photoinitiator type and concentrations were seen in color (where TPO resins became yellower and camphoroquinone resins became less yellow upon irradiation). Reaction temperature, kinetics and conversion also differed significantly for both initiators (presins producing a visually perceptible color change upon polymerization, the color change was significantly less than that produced with CQ-based resins. Although some photoinitiators such as TPO may be a more esthetic alternative to CQ, they may actually cause significant color contamination when

  9. Robust determination of effective atomic numbers for electron interactions with TLD-100 and TLD-100H thermoluminescent dosimeters

    International Nuclear Information System (INIS)

    Taylor, M.L.

    2011-01-01

    Lithium fluoride thermoluminescent dosimeters (TLD) are the most commonly implemented for clinical dosimetry. The small physical magnitude of TLDs makes them attractive for applications such as small field measurement, in vivo dosimetry and measurement of out-of-field doses to critical structures. The most broadly used TLD is TLD-100 (LiF:Mg,Ti) and, for applications requiring higher sensitivity to low-doses, TLD-100H (LiF:Mg,Cu,P) is frequently employed. The radiological properties of these TLDs are therefore of significant interest. For the first time, in this study effective atomic numbers for radiative, collisional and total electron interaction processes are calculated for TLD-100 and TLD-100H dosimeters over the energy range 1 keV-100 MeV. This is undertaken using a robust, energy-dependent method of calculation rather than typical power-law approximations. The influence of dopant concentrations and unwanted impurities is also investigated. The two TLDs exhibit similar effective atomic numbers, ranging from approximately 5.77-6.51. Differences arising from the different dopants are most pronounced in low-energy radiative effects. The TLDs have atomic numbers approximately 1.48-2.06 times that of water. The effective atomic number of TLD-100H is consistently higher than that of TLD-100 over a broad energy range, due to the greater influence of the higher-Z dopants on the electron interaction cross sections. Typical variation in dopant concentration does not significantly influence the effective atomic number. The influence on TLD-100H is comparatively more pronounced than that on TLD-100. Contrariwise, unwanted hydroxide impurities influence TLD-100 more than TLD-100H. The effective atomic number is a key parameter that influences the radiological properties and energy response of TLDs. Although many properties of these TLDs have been studied rigorously, as yet there has been no investigation of their effective atomic numbers for electron interactions. The

  10. Liquid metal reactor absorber technology

    International Nuclear Information System (INIS)

    Pitner, A.L.

    1990-10-01

    The selection of boron carbide as the reference liquid metal reactor absorber material is supported by results presented for irradiation performance, reactivity worth compatibility, and benign failure consequences. Scram response requirements are met easily with current control rod configurations. The trend in absorber design development is toward larger sized pins with fewer pins per bundle, providing economic savings and improved hydraulic characteristics. Very long-life absorber designs appear to be attainable with the application of vented pin and sodium-bonded concepts. 3 refs., 3 figs

  11. Diesel NO{sub x} reduction by plasma-regenerated absorbent beds

    Science.gov (United States)

    Wallman, P.H.; Vogtlin, G.E.

    1998-02-10

    Reduction of NO{sub x} from diesel engine exhaust by use of plasma-regenerated absorbent beds is described. This involves a process for the reduction of NO{sub x} and particulates from diesel engines by first absorbing NO{sub x} onto a solid absorbent bed that simultaneously acts as a physical trap for the particulate matter, and second regenerating said solid absorbent by pulsed plasma decomposition of absorbed NO{sub x} followed by air oxidation of trapped particulate matter. The absorbent bed may utilize all metal oxides, but the capacity and the kinetics of absorption and desorption vary between different materials, and thus the composition of the absorbent bed is preferably a material which enables the combination of NO{sub x} absorption capability with catalytic activity for oxidation of hydrocarbons. Thus, naturally occurring or synthetically prepared materials may be utilized, particularly those having NO{sub x} absorption properties up to temperatures around 400 C which is in the area of diesel engine exhaust temperatures. 1 fig.

  12. Particle beam technology for control of atomic-bonding state in materials

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, Junzo [Kyoto Univ. (Japan). Faculty of Engineering

    1997-03-01

    The atomic-bonding state in materials can be controlled through `kinetic bonding` process by energetic particle beams which have a sufficient atomic kinetic energy. In order to clarify the `kinetic bonding` process the negative-ion beam deposition is considered as an ideal method because the negative ion has no additional active energies. Sputter type heavy negative-ion sources can be used for this purpose. Carbon films prepared by carbon negative-ion beam deposition have a strong dependency of the film properties on ion beam kinetic energy and have a quite high thermal conductivity which is comparable to that of the IIb diamond at a kinetic energy of 50-100 eV/atom. It suggests that new or metastable materials could be formed through the `kinetic bonding` process. Negative-ion beams can also be used for ion implantation, in which charging problems are perfectly reduced. (author)

  13. Analysis of medical device materials with the local electrode atom probe

    International Nuclear Information System (INIS)

    Goodman, S.L.; Mengelt, T.J.; Ali, M.; Ulfig, R.M.; Martens, R.M.; Kelly, T.F.; Kostrna, S.L.P.; Kostrna, M.S.; Carmichael, W.J.

    2004-01-01

    Full text: As medical technology advances towards microsurgical and minimally invasive techniques, there is a drive to produce ever-smaller devices that demand higher material performance and hence enhanced nano and micro-scale control of material structure. These devices are made from stainless steel alloys, Nitinol, titanium, CoCrMo, and non-metals such as pyrolytic carbon and silicon. These applications are made possible due to suitable physical and mechanical properties, good corrosion resistance in biological environments, reasonable biocompatibility, and good manufacturability. With respect to the metals, the nano-structure and composition of the material surface, typically an oxide, is especially critical since biological responses and corrosion occur at the material-environment interface. Thus, there is an increasing need to understand the 3-D structure and composition of metallic biomaterials at the atomic scale. Three-dimensional atom probe microscopy can uniquely provide such atomic-level structural information. In the present study several of these medical device materials were examined. These include a 316L stainless steel alloy which is widely used in implanted spinal fixation devices, bone screws, cardiovascular and neurological stents, a cast CoCrMo acetabular hip cup of a Cormet metal-on-metal Hip Resurfacing System (Corin Group, Cirencester, England) that was rejected for clinical use, Nitinol wires specimens such as are used for stents and guide wires, and low temperature pyrolytic carbon as used in clinical heart valve prosthetics. (author)

  14. Systematic ab initio study of half-Heusler materials for optoelectronic applications

    Energy Technology Data Exchange (ETDEWEB)

    Gruhn, Thomas; Felser, Claudia [Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg University, Mainz (Germany)

    2010-07-01

    The development of new, optimized optoelectronic devices depends crucially on the availability of semiconductors with taylored electronic and structural properties. At the moment, the majority of applications is based on a rather small set of semiconducting materials, while many more semiconductors exist in the huge class of ternary compounds. Especially, the class of 8-electron half-Heusler materials comprises a large number semiconducters with various properties. With the help of ab initio density functional theory we have studied essentially all 8-electron half-Heusler compounds that are of technological relevance. For more than 650 compounds we have determined the optimum configuration by varying the lattice constant and permuting the elements over the sublattices. Within this exceptionally large data set we have studied the band structure and the lattice constants as a function of the electronegativities of the elements, the arrangement of the atoms, and the atomic radii. The results are used to select suitable materials for the buffer layer in thin-film solar cells with a Cu(In,Ga)Se{sub 2} (CIGS) absorber layer. Considering the bandgap and the geometrical matching with the CIGS film, we have obtained a set of 29 compounds that are promissing materials for cadmium-free CIGS buffer layer.

  15. Evaluation of absorbent materials for use as ad hoc dry decontaminants during mass casualty incidents as part of the UK's Initial Operational Response (IOR.

    Directory of Open Access Journals (Sweden)

    Nick Kassouf

    Full Text Available The UK's Initial Operational Response (IOR is a revised process for the medical management of mass casualties potentially contaminated with hazardous materials. A critical element of the IOR is the introduction of immediate, on-scene disrobing and decontamination of casualties to limit the adverse health effects of exposure. Ad hoc cleansing of the skin with dry absorbent materials has previously been identified as a potential means of facilitating emergency decontamination. The purpose of this study was to evaluate the in vitro oil and water absorbency of a range of materials commonly found in the domestic and clinical environments and to determine the effectiveness of a small, but representative selection of such materials in skin decontamination, using an established ex vivo model. Five contaminants were used in the study: methyl salicylate, parathion, diethyl malonate, phorate and potassium cyanide. In vitro measurements of water and oil absorbency did not correlate with ex vivo measurements of skin decontamination. When measured ex vivo, dry decontamination was consistently more effective than a standard wet decontamination method ("rinse-wipe-rinse" for removing liquid contaminants. However, dry decontamination was ineffective against particulate contamination. Collectively, these data confirm that absorbent materials such as wound dressings and tissue paper provide an effective, generic capability for emergency removal of liquid contaminants from the skin surface, but that wet decontamination should be used for non-liquid contaminants.

  16. Number series of atoms, interatomic bonds and interface bonds defining zinc-blende nanocrystals as function of size, shape and surface orientation: Analytic tools to interpret solid state spectroscopy data

    Directory of Open Access Journals (Sweden)

    Dirk König

    2016-08-01

    Full Text Available Semiconductor nanocrystals (NCs experience stress and charge transfer by embedding materials or ligands and impurity atoms. In return, the environment of NCs experiences a NC stress response which may lead to matrix deformation and propagated strain. Up to now, there is no universal gauge to evaluate the stress impact on NCs and their response as a function of NC size dNC. I deduce geometrical number series as analytical tools to obtain the number of NC atoms NNC(dNC[i], bonds between NC atoms Nbnd(dNC[i] and interface bonds NIF(dNC[i] for seven high symmetry zinc-blende (zb NCs with low-index faceting: {001} cubes, {111} octahedra, {110} dodecahedra, {001}-{111} pyramids, {111} tetrahedra, {111}-{001} quatrodecahedra and {001}-{111} quadrodecahedra. The fundamental insights into NC structures revealed here allow for major advancements in data interpretation and understanding of zb- and diamond-lattice based nanomaterials. The analytical number series can serve as a standard procedure for stress evaluation in solid state spectroscopy due to their deterministic nature, easy use and general applicability over a wide range of spectroscopy methods as well as NC sizes, forms and materials.

  17. Development of a Continuum Damage Mechanics Material Model of a Graphite-Kevlar(Registered Trademark) Hybrid Fabric for Simulating the Impact Response of Energy Absorbing Kevlar(Registered Trademark) Hybrid Fabric for Simulating the Impact Response of Energy Absorbing

    Science.gov (United States)

    Jackson, Karen E.; Fasanella, Edwin L.; Littell, Justin D.

    2017-01-01

    This paper describes the development of input properties for a continuum damage mechanics based material model, Mat 58, within LS-DYNA(Registered Trademark) to simulate the response of a graphite-Kevlar(Registered Trademark) hybrid plain weave fabric. A limited set of material characterization tests were performed on the hybrid graphite-Kevlar(Registered Trademark) fabric. Simple finite element models were executed in LS-DYNA(Registered Trademark) to simulate the material characterization tests and to verify the Mat 58 material model. Once verified, the Mat 58 model was used in finite element models of two composite energy absorbers: a conical-shaped design, designated the "conusoid," fabricated of four layers of hybrid graphite-Kevlar(Registered Trademark) fabric; and, a sinusoidal-shaped foam sandwich design, designated the "sinusoid," fabricated of the same hybrid fabric face sheets with a foam core. Dynamic crush tests were performed on components of the two energy absorbers, which were designed to limit average vertical accelerations to 25- to 40-g, to minimize peak crush loads, and to generate relatively long crush stroke values under dynamic loading conditions. Finite element models of the two energy absorbers utilized the Mat 58 model that had been verified through material characterization testing. Excellent predictions of the dynamic crushing response were obtained.

  18. Neutron absorbers, and the production method

    International Nuclear Information System (INIS)

    Kayano, Hideo; Yajima, Seishi; Oono, Hironori.

    1979-01-01

    Purpose: To integrally sinter a metal powder and a metal network material thereby to obtain a material having a high neutron absorbing function, an excellent corrosion resistance and an excellent oxidation resistance. Method: An element having a high neutron absorbing function, such as Gd, or a compound thereof and a powder of a metal having excellent corrosion resistance, oxidation resistance and ductility, such as Fe, Cr or the like are uniformly mixed with each other. In a case where a substance having a neutron absorbing function is a hydroxide an organic complex or the like, it is formed into a gel-like substance and mixed uniformly with the metal powder, the gel-like substance being pasted, and covered on the surface of the metal powder and dried. Then, the mixture or the dry coated material is extended and the metal network material having excellent corrosion resistance, oxidation resistance and ductility is covered or interposed or between at least one layer of upper, intermediate or lower layers of said laminated material, and thereafter is subjected to cold or hot rolling, and then sintered and furthermore rolled, if necessary, the thus treated material being burned in vacuum or a non-oxidizing atmosphere. (Kamimura, M.)

  19. Digital Alloy Absorber for Photodetectors

    Science.gov (United States)

    Hill, Cory J. (Inventor); Ting, David Z. (Inventor); Gunapala, Sarath D. (Inventor)

    2016-01-01

    In order to increase the spectral response range and improve the mobility of the photo-generated carriers (e.g. in an nBn photodetector), a digital alloy absorber may be employed by embedding one (or fraction thereof) to several monolayers of a semiconductor material (insert layers) periodically into a different host semiconductor material of the absorber layer. The semiconductor material of the insert layer and the host semiconductor materials may have lattice constants that are substantially mismatched. For example, this may performed by periodically embedding monolayers of InSb into an InAsSb host as the absorption region to extend the cutoff wavelength of InAsSb photodetectors, such as InAsSb based nBn devices. The described technique allows for simultaneous control of alloy composition and net strain, which are both key parameters for the photodetector operation.

  20. Design and testing of a shock absorber for a type 1 container

    International Nuclear Information System (INIS)

    Sappok, M.; Beine, B.; Rittscher, D.

    1993-01-01

    A shock-absorber will be required for a rad. waste 'Konrad' type 1 container made of ductile cast iron whenever it will be used as a type B container according to the IAEA-Regulations for the Safe Transport of Radioactive materials. The shock-absorber has to protect the type B container during shipping such as to withstand the accident scenarios that are covered by the IAEA-Regulation tests without substantial loss of its shielding and tightness functions. The designation as type 1 container originates from German regulations for the intermediate storage site Gorleben and the final depository Konrad-mine. These regulations call for the limits on outside dimensions of 1700 mm in length, 1600 mm in width and 1450 mm in height as well as for a limit of 20 Mg on total weight without shock-absorber. The relatively simple design method for the shock-absorber has been validated by the test results. It can be extended to other materials and designs for shock-absorbers if reliable force-displacement-diagrams are available for the structural elements from which the absorbed energy and the displacements can be calculated by integration. In order to account for the dynamic effects, the better approximation of the true duration of the impact would be helpful. The present limit of 0.5 R p0,2 on the nominal stresses should be discussed because the large number of tests on containers made of ductile cast iron that have been performed up to now have shown a substantial level of conservatism on this respect. The sharply tapered pipes on edge Kl of the shock-absorbers should be replaced by pipe bends. This will result in smaller accelerations and in an even higher level of protection of the container than effected by the tested shock-absorber

  1. Removing fuelling transient using neutron absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Paquette, S.; Chan, P.K.; Bonin, H.W., E-mail: Stephane.Paquette@rmc.ca [Royal Military College of Canada, Chemistry and Chemical Engineering Dept., Kingston, Ontario (Canada); Pant, A. [Cameco Fuel Manufacturing, Port Hope, Ontario (Canada)

    2012-07-01

    Preliminary criticality and burnup calculation results indicate that by employing a small amount of neutron absorber the fuelling transient, currently occurring in a CANDU 37-element fuel bundle, can be significantly reduced. A parametric study using the Los Alamos National Laboratories' MCNP 5 code and Atomic Energy of Canada Limited's WIMS-AECL 3.1 is presented in this paper. (author)

  2. Isoeffective dose: a concept for biological weighting of absorbed dose in proton and heavier-ion therapies

    CERN Document Server

    Wambersie, A; Menzel, H G; Gahbauer, R; DeLuca, P M; Hendry, J H; Jones, D T L

    2011-01-01

    When reporting radiation therapy procedures, International Commission on Radiation Units and Measurements (ICRU) recommends specifying absorbed dose at/in all clinically relevant points and/or volumes. In addition, treatment conditions should be reported as completely as possible in order to allow full understanding and interpretation of the treatment prescription. However, the clinical outcome does not only depend on absorbed dose but also on a number of other factors such as dose per fraction, overall treatment time and radiation quality radiation biology effectiveness (RBE). Therefore, weighting factors have to be applied when different types of treatments are to be compared or to be combined. This had led to the concept of `isoeffective absorbed dose', introduced by ICRU and International Atomic Energy Agency (IAEA). The isoeffective dose D(IsoE) is the dose of a treatment carried out under reference conditions producing the same clinical effects on the target volume as those of the actual treatment. It i...

  3. Additive manufacturing of RF absorbers

    Science.gov (United States)

    Mills, Matthew S.

    The ability of additive manufacturing techniques to fabricate integrated electromagnetic absorbers tuned for specific radio frequency bands within structural composites allows for unique combinations of mechanical and electromagnetic properties. These composites and films can be used for RF shielding of sensitive electromagnetic components through in-plane and out-of-plane RF absorption. Structural composites are a common building block of many commercial platforms. These platforms may be placed in situations in which there is a need for embedded RF absorbing properties along with structural properties. Instead of adding radar absorbing treatments to the external surface of existing structures, which adds increased size, weight and cost; it could prove to be advantageous to integrate the microwave absorbing properties directly into the composite during the fabrication process. In this thesis, a method based on additive manufacturing techniques of composites structures with prescribed electromagnetic loss, within the frequency range 1 to 26GHz, is presented. This method utilizes screen printing and nScrypt micro dispensing to pattern a carbon based ink onto low loss substrates. The materials chosen for this study will be presented, and the fabrication technique that these materials went through to create RF absorbing structures will be described. The calibration methods used, the modeling of the RF structures, and the applications in which this technology can be utilized will also be presented.

  4. Atomization mechanisms for barium in furnace atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Styris, D.L.

    1984-01-01

    Atomic absorption spectrometry and mass spectrometry are used simultaneously in order to elucidate atomization mechanisms of barium dichloride in pyrolytic graphite, vitreous carbon, and tantalum furnaces. Gas-phase barium dicarbide is observed to appear concurrently with the free barium. Barium oxide and barium dihydroxide precursors appear with the chlorides. Surface reactions involving species that are absorbed on the various furnaces are postulated to explain the appearances of the species that are observed in the gas phase. 49 references, 4 figures, 1 table

  5. A different perspective to the effective atomic number (Zeff) for some boron compounds and trommel sieve waste (TSW) with a new computer program ZXCOM

    International Nuclear Information System (INIS)

    Yalçın, Zeynel; İçelli, Orhan; Okutan, Mustafa; Boncukçuoğlu, Recep; Artun, Ozan; Orak, Salim

    2012-01-01

    In this study, the effective atomic number (Z eff )has been calculated for some boron compounds, such as concentrate colemanite, tincal, ulexite, boric acid, probertite and TSW (Trommel Sieve Waste) by means of ZXCOM at incident beam energy (E 0 =59.543 keV) and scattering angle (θ=35°). We present and discuss the (Z eff ) obtained by Rayleigh/Compton (R/C) ratio and evaluated for the purpose of radiation shielding which contains boron compounds, which are commonly used as shield materials. -- Highlights: ► The (Z eff ) of an infinite number of compounds will be determined according to the number actually consisting of elements which correspond to an integer number at the curve of ZXCOM. ► The result of this study shows that the effective atomic number (Z eff ) is closely related to the scattering angles. ► The main objective of the study is to construct a computer program, ZXCOM, to calculate the (Z eff ) at compromise (E 0 ) and (θ) for each element, compound and mixture.

  6. Tunable enhanced optical absorption of graphene using plasmonic perfect absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Yijun [Institute of Optoelectronic Technology, Department of Electronic Engineering, Xiamen University, Xiamen 361005 (China); Institute of Electromagnetics and Acoustics, Department of Electronic Science, Xiamen University, Xiamen 361005 (China); Zhu, Jinfeng, E-mail: nanoantenna@hotmail.com [Institute of Electromagnetics and Acoustics, Department of Electronic Science, Xiamen University, Xiamen 361005 (China); Liu, Qing Huo [Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708 (United States)

    2015-01-26

    Enhancement and manipulation of light absorption in graphene is a significant issue for applications of graphene-based optoelectronic devices. In order to achieve this purpose in the visible region, we demonstrate a design of a graphene optical absorber inspired by metal-dielectric-metal metamaterial for perfect absorption of electromagnetic waves. The optical absorbance ratios of single and three atomic layer graphene are enhanced up to 37.5% and 64.8%, respectively. The graphene absorber shows polarization-dependence and tolerates a wide range of incident angles. Furthermore, the peak position and bandwidth of graphene absorption spectra are tunable in a wide wavelength range through a specific structural configuration. These results imply that graphene in combination with plasmonic perfect absorbers have a promising potential for developing advanced nanophotonic devices.

  7. Thin absorbers for large-area soft X-ray microcalorimeters

    Energy Technology Data Exchange (ETDEWEB)

    Rocks, L. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States)]. E-mail: rocks@wisp.physics.wisc.edu; Anderson, M.B. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Bilgri, N. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Brekosky, R. [NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Gwynne Crowder, S. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Figueroa-Feliciano, E. [NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Kelley, R. [NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Kilbourne, C.A. [NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Lai, T. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Lindeman, M.A. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Man, J. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); McCammon, D. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Nelms, K.L. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Porter, F.S. [NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Sivananthan, S. [University of Illinois at Chicago, Chicago, IL 60607 (United States); Vidugiris, G. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Zhao, J. [University of Illinois at Chicago, Chicago, IL 60607 (United States)

    2006-04-15

    The X-ray Quantum Calorimeter (XQC) sounding rocket experiment utilizes a microcalorimeter array for observing the diffuse soft X-ray background. Observations of such low surface-brightness targets require a large-area detector. We will be using an array of large absorbers. Good absorbers must rapidly and completely thermalize photons, have small heat capacity for high stopping efficiency and have good lateral thermal transport. For observing the soft X-ray background (energies <1 keV), the volume and heat capacity of absorber material can be kept to a minimum by making the absorbers only as thick as needed for high quantum efficiency at these low energies. These thin, large-area absorbers are not self-supporting and have poor lateral heat transport. Depositing the absorber material on a Si substrate provides support and improves lateral thermal conduction. We present heat capacity results for thin HgTe and thin Bi, each on Si substrates. We also describe the HgTe absorber fabrication.

  8. Radar absorbing properties of carbon nanotubes/polymer ...

    Indian Academy of Sciences (India)

    This research is devoted to the study of radar absorbing properties of the composites, based on the epoxy binder and ... Radar absorbing materials; carbon nanotubes; nanocomposites; reflection loss. 1. ..... So, for example, the papers of [3–5 ...

  9. Effect of the bio-absorbent on the microwave absorption property of the flaky CIPs/rubber absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Yang; Xu, Yonggang, E-mail: xuyonggang221@163.com; Cai, Jun; Yuan, Liming; Zhang, Deyuan

    2015-09-01

    Microwave absorbing composites filled with flaky carbonyl iron particles (CIPs) and the bio-absorbent were prepared by using a two-roll mixer and a vulcanizing machine. The electromagnetic (EM) parameters were measured by a vector network analyzer and the reflection loss (RL) was measured by the arch method in the frequency range of 1–4 GHz. The uniform dispersion of the absorbents was verified by comparing the calculated RL with the measured one. The results confirm that as the bio-absorbent was added, the permittivity was increased due to the volume content of absorbents, and the permeability was enlarged owing to the volume content of CIPs and interactions between the two absorbents. The composite filled with bio-absorbents achieved an excellent absorption property at a thickness of 1 mm (minimum RL reaches −7.8 dB), and as the RL was less than −10 dB the absorption band was widest (2.1–3.8 GHz) at a thickness of 2 mm. Therefore, the bio-absorbent is a promising additive candidate on fabricating microwave absorbing composites with a thinner thickness and wider absorption band. - Graphical abstract: Morphology of composites filled with flaky CIPs and the bio-absorbent. The enhancement of bio-absorbent on the electromagnetic absorption property of composites filled with flaky carbonyl iron particles (CIPs) is attributed to the interaction of the two absorbents. The volume content of the FCMPs with the larger shape CIPs play an important role in this effects, the composites filled with irons and bio-absorbents can achieve wider-band and thinner-thickness absorbing materials. - Highlights: • Absorbers filled with bio-absorbents and CIPs was fabricated. • Bio-absorbents enhanced the permittivity and permeability of the composites. • The absorbent interactions play a key role in the enhancement mechanism. • Bio-absorbents enhanced the composite RL in 1–4 GHz.

  10. A wideband absorber for television studios

    Science.gov (United States)

    Baird, M. D. M.

    The acoustic treatment in BBC television has taken various forms to date, all of which have been relatively expensive, some of which provide inadequate absorption. An investigation has been conducted into the possibilities of producing a new type of wideband absorber which would be more economic, also taking installation time into account, than earlier designs. This Report describes the absorption coefficient measurements made on various combinations of materials, from which a wideband sound absorber has been developed. The absorber works efficiently between 50 Hz and 10 kHz, is simple and easy to construct using readily available materials, and is fire resistant. The design lends itself, if necessary, to on-site fine tuning, and savings in the region of 50 percent can be achieved in terms of cost and space with respect to previous designs.

  11. Metamaterial Absorber for Electromagnetic Waves in Periodic Water Droplets.

    Science.gov (United States)

    Yoo, Young Joon; Ju, Sanghyun; Park, Sang Yoon; Ju Kim, Young; Bong, Jihye; Lim, Taekyung; Kim, Ki Won; Rhee, Joo Yull; Lee, YoungPak

    2015-09-10

    Perfect metamaterial absorber (PMA) can intercept electromagnetic wave harmful for body in Wi-Fi, cell phones and home appliances that we are daily using and provide stealth function that military fighter, tank and warship can avoid radar detection. We reported new concept of water droplet-based PMA absorbing perfectly electromagnetic wave with water, an eco-friendly material which is very plentiful on the earth. If arranging water droplets with particular height and diameter on material surface through the wettability of material surface, meta-properties absorbing electromagnetic wave perfectly in GHz wide-band were shown. It was possible to control absorption ratio and absorption wavelength band of electromagnetic wave according to the shape of water droplet-height and diameter- and apply to various flexible and/or transparent substrates such as plastic, glass and paper. In addition, this research examined how electromagnetic wave can be well absorbed in water droplets with low electrical conductivity unlike metal-based metamaterials inquiring highly electrical conductivity. Those results are judged to lead broad applications to variously civilian and military products in the future by providing perfect absorber of broadband in all products including transparent and bendable materials.

  12. Atomic and plasma-material interaction data for fusion. Vol.1

    International Nuclear Information System (INIS)

    1991-01-01

    The International Atomic Energy Agency, through its Atomic and Molecular Data Unit, coordinates a wide spectrum of programmes for the compilation, evaluation, and generation of atomic, molecular, and plasma-wall interaction data for fusion research. The present, first, volume of Atomic and Plasma-Material Interaction Data for Fusion, contains extended versions of the reviews presented at the IAEA Advisory Group Meeting on Particle-Surface Interaction Data for Fusion, held 19-21 April 1989 at the IAEA Headquarters in Vienna, The plasma-wall interaction processes covered here are those considered most important for the operational performance of magnetic confinement fusion reactors. In addition to processes due to particle impact under normal operation, plasma-wall interaction effects due to off-normal plasma events (disruptions, electron runaway bombardment) are covered, and a summary of the status of data information on these processes is given from the point of view of magnetic fusion reactor design. Refs, figs and tabs

  13. Hydrogen storage materials discovery via high throughput ball milling and gas sorption.

    Science.gov (United States)

    Li, Bin; Kaye, Steven S; Riley, Conor; Greenberg, Doron; Galang, Daniel; Bailey, Mark S

    2012-06-11

    The lack of a high capacity hydrogen storage material is a major barrier to the implementation of the hydrogen economy. To accelerate discovery of such materials, we have developed a high-throughput workflow for screening of hydrogen storage materials in which candidate materials are synthesized and characterized via highly parallel ball mills and volumetric gas sorption instruments, respectively. The workflow was used to identify mixed imides with significantly enhanced absorption rates relative to Li2Mg(NH)2. The most promising material, 2LiNH2:MgH2 + 5 atom % LiBH4 + 0.5 atom % La, exhibits the best balance of absorption rate, capacity, and cycle-life, absorbing >4 wt % H2 in 1 h at 120 °C after 11 absorption-desorption cycles.

  14. Electromagnetic behavior of radar absorbing materials based on Ca hexaferrite modified with Co-Ti ions and doped with La

    Directory of Open Access Journals (Sweden)

    Valdirene Aparecida da Silva

    2009-06-01

    Full Text Available Radar Absorbing Materials (RAM are compounds that absorb incidental electromagnetic radiation in tuned frequencies and dissipate it as heat. Its preparation involves the adequate processing of polymeric matrices filled with compounds that act as radar absorbing centers in the microwave range. This work shows the electromagnetic evaluation of RAM based on CoTi and La doped Ca hexaferrite. Vibrating Sample Magnetization analyses show that ion substitution promoted low values for the parameters of saturation magnetization (123.65 Am2/kg and coercive field (0.07 T indicating ferrite softening. RAM samples obtained using different hexaferrite concentrations (40-80 per cent, w/w show variations in complex permeability and permittivity parameters and also in the performance of incidental radiation attenuation. Microwave attenuation values between 40 and 98 per cent were obtained.

  15. Synthesis of a New Element with Atomic Number Z=117

    International Nuclear Information System (INIS)

    Oganessian, Yu. Ts.; Abdullin, F. Sh.; Dmitriev, S. N.; Itkis, M. G.; Lobanov, Yu. V.; Mezentsev, A. N.; Polyakov, A. N.; Sagaidak, R. N.; Shirokovsky, I. V.; Subbotin, V. G.; Sukhov, A. M.; Tsyganov, Yu. S.; Utyonkov, V. K.; Voinov, A. A.; Vostokin, G. K.; Bailey, P. D.; Benker, D. E.; Ezold, J. G.; Porter, C. E.; Riley, F. D.

    2010-01-01

    The discovery of a new chemical element with atomic number Z=117 is reported. The isotopes 293 117 and 294 117 were produced in fusion reactions between 48 Ca and 249 Bk. Decay chains involving 11 new nuclei were identified by means of the Dubna gas-filled recoil separator. The measured decay properties show a strong rise of stability for heavier isotopes with Z≥111, validating the concept of the long sought island of enhanced stability for superheavy nuclei.

  16. SU-C-BRC-05: Monte Carlo Calculations to Establish a Simple Relation of Backscatter Dose Enhancement Around High-Z Dental Alloy to Its Atomic Number

    Energy Technology Data Exchange (ETDEWEB)

    Utsunomiya, S; Kushima, N; Katsura, K; Tanabe, S; Hayakawa, T; Sakai, H; Yamada, T; Takahashi, H; Abe, E; Wada, S; Aoyama, H [Niigata University, Niigata (Japan)

    2016-06-15

    Purpose: To establish a simple relation of backscatter dose enhancement around a high-Z dental alloy in head and neck radiation therapy to its average atomic number based on Monte Carlo calculations. Methods: The PHITS Monte Carlo code was used to calculate dose enhancement, which is quantified by the backscatter dose factor (BSDF). The accuracy of the beam modeling with PHITS was verified by comparing with basic measured data namely PDDs and dose profiles. In the simulation, a high-Z alloy of 1 cm cube was embedded into a tough water phantom irradiated by a 6-MV (nominal) X-ray beam of 10 cm × 10 cm field size of Novalis TX (Brainlab). The ten different materials of high-Z alloys (Al, Ti, Cu, Ag, Au-Pd-Ag, I, Ba, W, Au, Pb) were considered. The accuracy of calculated BSDF was verified by comparing with measured data by Gafchromic EBT3 films placed at from 0 to 10 mm away from a high-Z alloy (Au-Pd-Ag). We derived an approximate equation to determine the relation of BSDF and range of backscatter to average atomic number of high-Z alloy. Results: The calculated BSDF showed excellent agreement with measured one by Gafchromic EBT3 films at from 0 to 10 mm away from the high-Z alloy. We found the simple linear relation of BSDF and range of backscatter to average atomic number of dental alloys. The latter relation was proven by the fact that energy spectrum of backscatter electrons strongly depend on average atomic number. Conclusion: We found a simple relation of backscatter dose enhancement around high-Z alloys to its average atomic number based on Monte Carlo calculations. This work provides a simple and useful method to estimate backscatter dose enhancement from dental alloys and corresponding optimal thickness of dental spacer to prevent mucositis effectively.

  17. Nanostructured composites based on carbon nanotubes and epoxy resin for use as radar absorbing materials

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Valdirene Aparecida [Instituto Tecnologico de Aeronautica (ITA), Sao Jose dos Campos, SP (Brazil); Folgueras, Luiza de Castro; Candido, Geraldo Mauricio; Paula, Adriano Luiz de; Rezende, Mirabel Cerqueira, E-mail: mirabelmcr@iae.cta.br [Instituto de Aeronautica e Espaco (IAE), Sao Jose dos Campos, SP (Brazil). Div. de Materiais; Costa, Michelle Leali [Universidade Estadual Paulista Julio de Mesquita Filho (DMT/UNESP), Guaratingueta, SP (Brazil). Dept. de Materiais e Tecnologia

    2013-07-01

    Nanostructured polymer composites have opened up new perspectives for multifunctional materials. In particular, carbon nanotubes (CNTs) present potential applications in order to improve mechanical and electrical performance in composites with aerospace application. The combination of epoxy resin with multi walled carbon nanotubes results in a new functional material with enhanced electromagnetic properties. The objective of this work was the processing of radar absorbing materials based on formulations containing different quantities of carbon nanotubes in an epoxy resin matrix. To reach this objective the adequate concentration of CNTs in the resin matrix was determined. The processed structures were characterized by scanning electron microscopy, rheology, thermal and reflectivity in the frequency range of 8.2 to 12.4 GHz analyses. The microwave attenuation was up to 99.7%, using only 0.5% (w/w) of CNT, showing that these materials present advantages in performance associated with low additive concentrations (author)

  18. Investigation of blister formation in sputtered Cu{sub 2}ZnSnS{sub 4} absorbers for thin film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Bras, Patrice, E-mail: patrice.bras@angstrom.uu.se [Midsummer AB, Elektronikhöjden 6, SE-17543 Järfälla, Sweden and Solid State Electronics, Angström Laboratory, Uppsala University, Box 534, SE-75121 Uppsala (Sweden); Sterner, Jan [Midsummer AB, Elektronikhöjden 6, SE-17543 Järfälla (Sweden); Platzer-Björkman, Charlotte [Solid State Electronics, Angström Laboratory, Uppsala University, Box 534, SE-75121 Uppsala (Sweden)

    2015-11-15

    Blister formation in Cu{sub 2}ZnSnS{sub 4} (CZTS) thin films sputtered from a quaternary compound target is investigated. While the thin film structure, composition, and substrate material are not correlated to the blister formation, a strong link between sputtering gas entrapment, in this case argon, and blistering effect is found. It is shown that argon is trapped in the film during sputtering and migrates to locally form blisters during the high temperature annealing. Blister formation in CZTS absorbers is detrimental for thin film solar cell fabrication causing partial peeling of the absorber layer and potential shunt paths in the complete device. Reduced sputtering gas entrapment, and blister formation, is seen for higher sputtering pressure, higher substrate temperature, and change of sputtering gas to larger atoms. This is all in accordance with previous publications on blister formation caused by sputtering gas entrapment in other materials.

  19. Atomic structure and electronic properties of the SixSb100-x phase-change memory material

    DEFF Research Database (Denmark)

    Verma, Ashok K.; Modak, Paritosh; Svane, Axel

    2011-01-01

    The electronic and structural properties of SixSb100-x (x∼16) materials are investigated using first-principles molecular dynamics simulations. Crystalline-liquid-amorphous phase transitions are examined and remarkable changes in the local structure around the Si atoms are found. The average Si...... coordination number 6 (3 long + 3 short Si-Sb bonds) of the crystalline phase changes to 4 (3 long Si-Sb + 1 short Si-Si bonds) by preserving three Si-Sb bonds in both the liquid and the amorphous phases. In the amorphous phase ∼90% of the Si atoms are fourfold coordinated compared to 40% in the liquid....... The electronic density of states is metal-like in both the crystalline and the liquid phases, but it exhibits a pseudogap at the Fermi level in the amorphous phase, reflecting the strong abundance of fourfold coordinated Si in the amorphous phase....

  20. Number series of atoms, interatomic bonds and interface bonds defining zinc-blende nanocrystals as function of size, shape and surface orientation: Analytic tools to interpret solid state spectroscopy data

    Energy Technology Data Exchange (ETDEWEB)

    König, Dirk, E-mail: dirk.koenig@unsw.edu.au [Integrated Materials Design Centre (IMDC) and School of Photovoltaic and Renewable Energy Engineering (SPREE), University of New South Wales, Sydney (Australia)

    2016-08-15

    Semiconductor nanocrystals (NCs) experience stress and charge transfer by embedding materials or ligands and impurity atoms. In return, the environment of NCs experiences a NC stress response which may lead to matrix deformation and propagated strain. Up to now, there is no universal gauge to evaluate the stress impact on NCs and their response as a function of NC size d{sub NC}. I deduce geometrical number series as analytical tools to obtain the number of NC atoms N{sub NC}(d{sub NC}[i]), bonds between NC atoms N{sub bnd}(d{sub NC}[i]) and interface bonds N{sub IF}(d{sub NC}[i]) for seven high symmetry zinc-blende (zb) NCs with low-index faceting: {001} cubes, {111} octahedra, {110} dodecahedra, {001}-{111} pyramids, {111} tetrahedra, {111}-{001} quatrodecahedra and {001}-{111} quadrodecahedra. The fundamental insights into NC structures revealed here allow for major advancements in data interpretation and understanding of zb- and diamond-lattice based nanomaterials. The analytical number series can serve as a standard procedure for stress evaluation in solid state spectroscopy due to their deterministic nature, easy use and general applicability over a wide range of spectroscopy methods as well as NC sizes, forms and materials.

  1. Cooperative single-photon subradiant states in a three-dimensional atomic array

    Energy Technology Data Exchange (ETDEWEB)

    Jen, H.H., E-mail: sappyjen@gmail.com

    2016-11-15

    We propose a complete superradiant and subradiant states that can be manipulated and prepared in a three-dimensional atomic array. These subradiant states can be realized by absorbing a single photon and imprinting the spatially-dependent phases on the atomic system. We find that the collective decay rates and associated cooperative Lamb shifts are highly dependent on the phases we manage to imprint, and the subradiant state of long lifetime can be found for various lattice spacings and atom numbers. We also investigate both optically thin and thick atomic arrays, which can serve for systematic studies of super- and sub-radiance. Our proposal offers an alternative scheme for quantum memory of light in a three-dimensional array of two-level atoms, which is applicable and potentially advantageous in quantum information processing. - Highlights: • Cooperative single-photon subradiant states in a three-dimensional atomic array. • Subradiant state manipulation via spatially-increasing phase imprinting. • Quantum storage of light in the subradiant state in two-level atoms.

  2. Energy Absorbing Effectiveness – Different Approaches

    Directory of Open Access Journals (Sweden)

    Kotełko Maria

    2018-03-01

    Full Text Available In the paper the study of different crashworthiness indicators used to evaluate energy absorbing effectiveness of thin-walled energy absorbers is presented. Several different indicators are used to assess an effectiveness of two types of absorbing structures, namely thin-walled prismatic column with flaws and thin-walled prismatic frustum (hollow or foam filled in both cases subjected to axial compressive impact load. The indicators are calculated for different materials and different geometrical parameters. The problem of selection of the most appropriate and general indicators is discussed.

  3. Bloch oscillations of ultracold atoms and measurement of the fine structure constant; Oscillations de Bloch d'atomes ultrafroids et mesure de la constante de structure fine

    Energy Technology Data Exchange (ETDEWEB)

    Clade, P

    2005-10-15

    From a measurement of the recoil velocity of an atom absorbing a photon, it is possible to deduce a determination of the ratio h/m between the Planck constant and the mass of the atoms and then to deduce a value of the fine structure constant alpha. To do this measurement, we use the technique of Bloch oscillations, which allows us to transfer a large number of recoils to atoms. A velocity sensor, based on velocity selective Raman transition, enables us to measure the momentum transferred to the atoms. A measurement with a statistical uncertainty of 4.4 10{sup -9}, in conjunction with a careful study of systematic effects (5 10{sup -9}), has led us to a determination of alpha with an uncertainty of 6.7 10{sup -9}: {alpha}{sup -1}(Rb) = 137.03599878 (91). This uncertainty is similar to the uncertainty of the best determinations of alpha based on atom interferometry. (author)

  4. Theoretical Calculation of Absolute Radii of Atoms and Ions. Part 1. The Atomic Radii

    Directory of Open Access Journals (Sweden)

    Raka Biswas

    2002-02-01

    Full Text Available Abstract. A set of theoretical atomic radii corresponding to the principal maximum in the radial distribution function, 4πr2R2 for the outermost orbital has been calculated for the ground state of 103 elements of the periodic table using Slater orbitals. The set of theoretical radii are found to reproduce the periodic law and the Lother Meyer’s atomic volume curve and reproduce the expected vertical and horizontal trend of variation in atomic size in the periodic table. The d-block and f-block contractions are distinct in the calculated sizes. The computed sizes qualitatively correlate with the absolute size dependent properties like ionization potentials and electronegativity of elements. The radii are used to calculate a number of size dependent periodic physical properties of isolated atoms viz., the diamagnetic part of the atomic susceptibility, atomic polarizability and the chemical hardness. The calculated global hardness and atomic polarizability of a number of atoms are found to be close to the available experimental values and the profiles of the physical properties computed in terms of the theoretical atomic radii exhibit their inherent periodicity. A simple method of computing the absolute size of atoms has been explored and a large body of known material has been brought together to reveal how many different properties correlate with atomic size.

  5. Proposal concerning the absorbed dose conversion factor

    Energy Technology Data Exchange (ETDEWEB)

    Shiragai, A [National Inst. of Radiological Sciences, Chiba (Japan)

    1978-03-01

    New definitions of the absorbed dose conversion factors Csub(lambda) and Csub(E) are proposed. The absorbed dose in water is given by the product of absorbed dose conversion factor, exposure calibration factor, ionisation chamber reading, cap displacement correction factor and perturbation correction factor. At exposure calibration the material of the build-up cap must be the same as that of the chamber wall. An ionisation chamber of which the wall material is water-equivalent or air-equivalent may be used. In the latter case the wall must be thin. For these two cases absorbed dose conversion factors are introduced and it is recommended that either of the two sets should be adopted. Furthermore, if the chamber wall is neither water- nor air-equivalent, the factor by which these currently defined values should be multiplied is also given: again the wall must be thin. The ICRU definitions of Csub(lambda) and Csub(E) are inconsistent, as recently pointed out, while the definitions presented here are consistent.

  6. Strategy for designing stable and powerful nitrogen-rich high-energy materials by introducing boron atoms.

    Science.gov (United States)

    Wu, Wen-Jie; Chi, Wei-Jie; Li, Quan-Song; Li, Ze-Sheng

    2017-06-01

    One of the most important aims in the development of high-energy materials is to improve their stability and thus ensure that they are safe to manufacture and transport. In this work, we theoretically investigated open-chain N 4 B 2 isomers using density functional theory in order to find the best way of stabilizing nitrogen-rich molecules. The results show that the boron atoms in these isomers are aligned linearly with their neighboring atoms, which facilitates close packing in the crystals of these materials. Upon comparing the energies of nine N 4 B 2 isomers, we found that the structure with alternating N and B atoms had the lowest energy. Structures with more than one nitrogen atom between two boron atoms had higher energies. The energy of N 4 B 2 increases by about 50 kcal/mol each time it is rearranged to include an extra nitrogen atom between the two boron atoms. More importantly, our results also show that boron atoms stabilize nitrogen-rich molecules more efficiently than carbon atoms do. Also, the combustion of any isomer of N 4 B 2 releases more heat than the corresponding isomer of N 4 C 2 does under well-oxygenated conditions. Our study suggests that the three most stable N 4 B 2 isomers (BN13, BN24, and BN34) are good candidates for high-energy molecules, and it outlines a new strategy for designing stable boron-containing high-energy materials. Graphical abstract The structural characteristics, thermodynamic stabilities, and exothermic properties of nitrogen-rich N 4 B 2 isomers were investigated by means of density functional theory.

  7. Atomic-resolution transmission electron microscopy of electron beam–sensitive crystalline materials

    Science.gov (United States)

    Zhang, Daliang; Zhu, Yihan; Liu, Lingmei; Ying, Xiangrong; Hsiung, Chia-En; Sougrat, Rachid; Li, Kun; Han, Yu

    2018-02-01

    High-resolution imaging of electron beam–sensitive materials is one of the most difficult applications of transmission electron microscopy (TEM). The challenges are manifold, including the acquisition of images with extremely low beam doses, the time-constrained search for crystal zone axes, the precise image alignment, and the accurate determination of the defocus value. We develop a suite of methods to fulfill these requirements and acquire atomic-resolution TEM images of several metal organic frameworks that are generally recognized as highly sensitive to electron beams. The high image resolution allows us to identify individual metal atomic columns, various types of surface termination, and benzene rings in the organic linkers. We also apply our methods to other electron beam–sensitive materials, including the organic-inorganic hybrid perovskite CH3NH3PbBr3.

  8. Atomic-resolution transmission electron microscopy of electron beam–sensitive crystalline materials

    KAUST Repository

    Zhang, Daliang

    2018-01-18

    High-resolution imaging of electron beam-sensitive materials is one of the most difficult applications of transmission electron microscopy (TEM). The challenges are manifold, including the acquisition of images with extremely low beam doses, the time-constrained search for crystal zone axes, the precise image alignment, and the accurate determination of the defocus value. We develop a suite of methods to fulfill these requirements and acquire atomic-resolution TEM images of several metal organic frameworks that are generally recognized as highly sensitive to electron beams. The high image resolution allows us to identify individual metal atomic columns, various types of surface termination, and benzene rings in the organic linkers. We also apply our methods to other electron beam–sensitive materials, including the organic-inorganic hybrid perovskite CH3NH3PbBr3.

  9. Aluminum alloy excellent in neutron absorbing performance

    International Nuclear Information System (INIS)

    Iida, Tetsuya; Tamamura, Tadao; Morimoto, Hiroyuki; Ouchi, Ken-ichiro.

    1987-01-01

    Purpose: To obtain structural materials made of aluminum alloys having favorable neutron absorbing performance and excellent in the performance as structural materials such as processability and strength. Constitution: Powder of Gd 2 O 3 as a gadolinium compound or metal gadolinium is uniformly mixed with the powder of aluminum or aluminum alloy. The amount of the gadolinium compound added is set to 0.1 - 30 % by weight. No sufficient neutron absorbing performance can be obtained if it is less than 0.1 % by weight, whereas the processability and mechanical property of the alloy are degraded if it exceeds 30 % by weight. Further, the grain size is set to less about 50 μm. Further, since the neutron absorbing performance varies greatly if the aluminum powder size exceeds 100 μm, the diameter is set to less than about 100 μm. These mixtures are molded in a hot press. This enables to obtain aimed structural materials. (Takahashi, M.)

  10. Synthesis of Novel UV Absorbers Bisindolylmethanes and Investigation of Their Applications on Cotton-Based Textile Materials

    Directory of Open Access Journals (Sweden)

    Hikmet Nil Ergindemir

    2016-06-01

    Full Text Available Nowadays modified textiles, especially UV-protective, antibacterial and antimicrobial ones, have become the focus of great interest. In this study, several new UV absorbers, bis(indolylmethane derivatives, were synthesized and grafted onto polyvinyl alcohol polymer (PVA. Their application properties on cotton-based textile materials were determined; the UV protection factor values of the modified fabrics were measured (UPF; and the antibacterial features of the fabrics were tested.

  11. Energy deposition studies for the LBNE beam absorber

    International Nuclear Information System (INIS)

    Rakhno, Igor L.; Mokhov, Nikolai V.; Tropin, Igor S.

    2015-01-01

    Results of detailed Monte Carlo energy deposition studies performed for the LBNE absorber core and the surrounding shielding with the MARS15 code are described. The model of the entire facility that includes a pion-production target, focusing horns, target chase, decay channel, hadron absorber system - all with corresponding radiation shielding - was developed using the recently implemented ROOT-based geometry option in the MARS15 code. This option provides substantial flexibility and automation when developing complex geometry models. Both normal operation and accidental conditions were studied. Various design options were considered, in particular the following: (i) filling the decay pipe with air or helium; (ii) the absorber mask material and shape; (iii) the beam spoiler material and size. Results of detailed thermal calculations with the ANSYS code helped to select the most viable absorber design options. (authors)

  12. On the high-temperature desulfurization of coal gas: The development of a regenerable absorbent

    Energy Technology Data Exchange (ETDEWEB)

    Van Yperen, Renee

    1994-05-18

    There is actually no solid absorbent based on bulk metal oxides available that meets the conditions for application in high-temperature desulfurization processes. This research was aimed to develop an absorbent that fulfills all the specifications for employment in hot-gas clean up. Chapter 2 deals with the development of amorphous aluminium phosphate as a support material. The influence of the preparation conditions onto the specific surface area, pore structure, thermal and chemical stability, and acidity of amorphous aluminium phosphate was investigated. The application of iron oxide onto amorphous aluminium phosphate by means of deposition-precipitation from a homogeneous solution is discussed in chapter 3. The influence of amorphous aluminium phosphate onto the stability, activity, and capacity of the iron oxide is described in detail. Chapter 4 surveys the activity and capacity of several active materials in the absorption of hydrogen sulphide. It is shown that the most promising active material is a mixture of iron oxide and molybdenum oxide. In chapter 5 the properties of iron-molybdenum mixed oxide absorbents are discussed. The effect of the iron to molybdenum ratio onto the formation of iron-(III)-sulphates and the stability of the molybdenum compound is examined. Chapter 6 deals with the preparation of iron-molybdenum mixed oxide absorbents by means of impregnation of modified pre-shaped alumina support bodies. In chapter 7 the effect of the hydrogen and carbon monoxide concentration and in chapter 8 the effect of the water concentration in the coal gas on the activity and the capacity of the iron-molybdenum mixed oxide absorbents is described. Regeneration of the loaded absorbents is an important part of the desulfurization process, dealt with in chapter 9. A number of regeneration procedures have been tested. (Abstract Truncated)

  13. Passivation of black phosphorus saturable absorbers for reliable pulse formation of fiber lasers.

    Science.gov (United States)

    Na, Dongsoo; Park, Kichul; Park, Ki-Hwan; Song, Yong-Won

    2017-11-24

    Black phosphorus (BP) has attracted increasing attention due to its unique electrical properties. In addition, the outstanding optical nonlinearity of BP has been demonstrated in various ways. Its functionality as a saturable absorber, in particular, has been validated in demonstrations of passive mode-locked lasers. However, normally, the performance of BP is degraded eventually by both thermal and chemical damage in ambient conditions. The passivation of BP is the critical issue to guarantee a stable performance of the optical devices. We quantitatively characterized the mode-locked lasers operated by BP saturable absorbers with diversified passivation materials such as polydimethylsiloxane (PDMS) or Al 2 O 3 , considering the atomic structure of the materials, and therefore the hydro-permeability of the passivation layers. Unlike the BP layers without passivation, we demonstrated that the Al 2 O 3 -passivated BP layer was protected from the surface oxidation reaction in the long-term, and the PDMS-passivated one had a short-term blocking effect. The quantitative analysis showed that the time-dependent characteristics of the pulsed laser without passivation were changed with respect to the pulse duration, spectral width, and time-bandwidth product displaying 550 fs, 2.8 nm, and 0.406, respectively. With passivation, the changes were limited to <43 fs, <0.3 nm, and <0.012, respectively.

  14. Passivation of black phosphorus saturable absorbers for reliable pulse formation of fiber lasers

    Science.gov (United States)

    Na, Dongsoo; Park, Kichul; Park, Ki-Hwan; Song, Yong-Won

    2017-11-01

    Black phosphorus (BP) has attracted increasing attention due to its unique electrical properties. In addition, the outstanding optical nonlinearity of BP has been demonstrated in various ways. Its functionality as a saturable absorber, in particular, has been validated in demonstrations of passive mode-locked lasers. However, normally, the performance of BP is degraded eventually by both thermal and chemical damage in ambient conditions. The passivation of BP is the critical issue to guarantee a stable performance of the optical devices. We quantitatively characterized the mode-locked lasers operated by BP saturable absorbers with diversified passivation materials such as polydimethylsiloxane (PDMS) or Al2O3, considering the atomic structure of the materials, and therefore the hydro-permeability of the passivation layers. Unlike the BP layers without passivation, we demonstrated that the Al2O3-passivated BP layer was protected from the surface oxidation reaction in the long-term, and the PDMS-passivated one had a short-term blocking effect. The quantitative analysis showed that the time-dependent characteristics of the pulsed laser without passivation were changed with respect to the pulse duration, spectral width, and time-bandwidth product displaying 550 fs, 2.8 nm, and 0.406, respectively. With passivation, the changes were limited to <43 fs, <0.3 nm, and <0.012, respectively.

  15. A practical relation between atomic numbers and alpha coefficients

    International Nuclear Information System (INIS)

    Lachance, G.R.

    1980-01-01

    A first approximation indicates that fundamental alpha coefficients for a given analyte vary as a function of the ratio of their respective atomic number raised to a power. This simple rule applies mainly at the limits (i.e., when the weight fraction of analyte i, Wsub(i) is of the order of 0.0 or 1.0) in cases of absorption and weak enhancement. The relation thus provides a means of generating coefficients for the system i-k from experimental data obtained on system i-j and a means of verifying experimental alphas, since arrays of coefficients must show a high degree of concordance. (author)

  16. Megavoltage cargo radiography with dual energy material decomposition

    Science.gov (United States)

    Shikhaliev, Polad M.

    2018-02-01

    Megavoltage (MV) radiography has important applications in imaging large cargos for detecting illicit materials. A useful feature of MV radiography is the possibility of decomposing and quantifying materials with different atomic numbers. This can be achieved by imaging cargo at two different X-ray energies, or dual energy (DE) radiography. The performance of both single energy and DE radiography depends on beam energy, beam filtration, radiation dose, object size, and object content. The purpose of this work was to perform comprehensive qualitative and quantitative investigations of the image quality in MV radiography depending on the above parameters. A digital phantom was designed including Fe background with thicknesses of 2cm, 6cm, and 18cm, and materials samples of Polyethylene, Fe, Pb, and U. The single energy images were generated at x-ray beam energies 3.5MV, 6MV, and 9MV. The DE material decomposed images were generated using interlaced low and high energy beams 3.5/6MV and 6/9MV. The X-ray beams were filtered by low-Z (Polyethylene) and high-Z (Pb) filters with variable thicknesses. The radiation output of the accelerator was kept constant for all beam energies. The image quality metrics was signal-to-noise ratio (SNR) of the particular sample over a particular background. It was found that the SNR depends on the above parameters in a complex way, but can be optimized by selecting a particular set of parameters. For some imaging setups increased filter thicknesses, while strongly absorbing the beams, increased the SNR of material decomposed images. Beam hardening due to polyenergetic x-ray spectra resulted in material decomposition errors, but this could be addressed using region of interest decomposition. It was shown that it is not feasible to separate the materials with close atomic numbers using the DE method. Particularly, Pb and U were difficult to decompose, at least at the dose levels allowed by radiation source and safety requirements.

  17. A black body absorber from vertically aligned single-walled carbon nanotubes

    Science.gov (United States)

    Mizuno, Kohei; Ishii, Juntaro; Kishida, Hideo; Hayamizu, Yuhei; Yasuda, Satoshi; Futaba, Don N.; Yumura, Motoo; Hata, Kenji

    2009-01-01

    Among all known materials, we found that a forest of vertically aligned single-walled carbon nanotubes behaves most similarly to a black body, a theoretical material that absorbs all incident light. A requirement for an object to behave as a black body is to perfectly absorb light of all wavelengths. This important feature has not been observed for real materials because materials intrinsically have specific absorption bands because of their structure and composition. We found a material that can absorb light almost perfectly across a very wide spectral range (0.2–200 μm). We attribute this black body behavior to stem from the sparseness and imperfect alignment of the vertical single-walled carbon nanotubes. PMID:19339498

  18. Safety implications of anomalous effects of neutron absorbers on criticality

    International Nuclear Information System (INIS)

    Clayton, E.D.

    1987-04-01

    A number of ''anomalies'' in nuclear criticality have been disclosed in recent years, and as new data have become available additional anomalies have come to light. Application of existing data, without familiarity with the anomalies could lead to diminished criticality control, or more costly less efficient control. As neutron absobers are frequently used for criticality control, this paper briefly presents and discusses six apparent anomalies pertaining to the effect of neutron absorbers on the criticality of fissionable material

  19. Frequency Tuning of Vibration Absorber Using Topology Optimization

    Science.gov (United States)

    Harel, Swapnil Subhash

    A tuned mass absorber is a system for reducing the amplitude in one oscillator by coupling it to a second oscillator. If tuned correctly, the maximum amplitude of the first oscillator in response to a periodic driver will be lowered, and much of the vibration will be 'transferred' to the second oscillator. The tuned vibration absorber (TVA) has been utilized for vibration control purposes in many sectors of Civil/Automotive/Aerospace Engineering for many decades since its inception. Time and again we come across a situation in which a vibratory system is required to run near resonance. In the past, approaches have been made to design such auxiliary spring mass tuned absorbers for the safety of the structures. This research focuses on the development and optimization of continuously tuned mass absorbers as a substitute to the discretely tuned mass absorbers (spring- mass system). After conducting the study of structural behavior, the boundary condition and frequency to which the absorber is to be tuned are determined. The Modal analysis approach is used to determine mode shapes and frequencies. The absorber is designed and optimized using the topology optimization tool, which simultaneously designs, optimizes and tunes the absorber to the desired frequency. The tuned, optimized absorber, after post processing, is attached to the target structure. The number of the absorbers are increased to amplify bandwidth and thereby upgrade the safety of structure for a wide range of frequency. The frequency response analysis is carried out using various combinations of structure and number of absorber cell.

  20. New high-throughput material-exploration system based on combinatorial chemistry and electrostatic atomization

    International Nuclear Information System (INIS)

    Fujimoto, K.; Takahashi, H.; Ito, S.; Inoue, S.; Watanabe, M.

    2006-01-01

    As a tool to facilitate future material explorations, our group has developed a new combinatorial system for the high-throughput preparation of compounds made up of more than three components. The system works in two steps: the atomization of a liquid by a high electric field followed by deposition to a grounded substrate. The combinatorial system based on this method has plural syringe pumps. The each starting materials are fed through the syringe pumps into a manifold, thoroughly mixed as they pass through the manifold, and atomized from the tip of a stainless steel nozzle onto a grounded substrate

  1. Bloch oscillations of ultracold atoms and measurement of the fine structure constant

    International Nuclear Information System (INIS)

    Clade, P.

    2005-10-01

    From a measurement of the recoil velocity of an atom absorbing a photon, it is possible to deduce a determination of the ratio h/m between the Planck constant and the mass of the atoms and then to deduce a value of the fine structure constant alpha. To do this measurement, we use the technique of Bloch oscillations, which allows us to transfer a large number of recoils to atoms. A velocity sensor, based on velocity selective Raman transition, enables us to measure the momentum transferred to the atoms. A measurement with a statistical uncertainty of 4.4 10 -9 , in conjunction with a careful study of systematic effects (5 10 -9 ), has led us to a determination of alpha with an uncertainty of 6.7 10 -9 : α -1 (Rb) = 137.03599878 (91). This uncertainty is similar to the uncertainty of the best determinations of alpha based on atom interferometry. (author)

  2. Atomic and plasma-material interaction data for fusion. V. 5

    International Nuclear Information System (INIS)

    1994-01-01

    Volume 5 of the supplements on ''atomic and plasma-material interaction data for fusion'' to the journal ''Nuclear Fusion'' is devoted to a critical assessment of the physical and thermo-mechanical properties of presently considered candidate plasma-facing and structural materials for next-generation thermonuclear fusion devices. It contains 9 papers. The subjects are: (i) requirements and selection criteria for plasma-facing materials and components in the ITER EDA (Engineering Design Activities) design; (ii) thermomechanical properties of Beryllium; (iii) material properties data for fusion reactor plasma-facing carbon-carbon composites; (iv) high-Z candidate plasma facing materials; (v) recommended property data for Molybdenum, Niobium and Vanadium alloys; (vi) copper alloys for high heat flux structure applications; (vii) erosion of plasma-facing materials during a tokamak disruption; (viii) runaway electron effects; and (ix) data bases for thermo-hydrodynamic coupling with coolants. Refs, figs, tabs

  3. Characterization of grain boundaries in Cu(In,Ga)Se{sub 2} by atom probe tomography

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, Torsten; Cojocaru-Miredin, Oana; Choi, Pyuck-Pa; Raabe, Dierk [Max-Planck Institute for Iron Research GmbH, Duesseldorf (Germany); Wuerz, Roland [Zentrum fuer Sonnenenergie- und Wasserstoff-Forschung Baden-Wuerttemberg (ZSW), Stuttgart (Germany)

    2012-07-01

    Solar cells based on the compound semiconductor Cu(In,Ga)Se{sub 2} (CIGS) as absorber material exhibit the highest efficiency among all thin-film solar cells. This is surprising high in view of the polycrystalline defect-rich structure of the CIGS absorber films. The high efficiency has been commonly ascribed to the diffusion of alkali metal atoms from the soda-lime glass substrate into the CIGS layer, which can render the grain boundaries (GB) electrically inactive. However, the exact mechanisms of how these impurities enhance the cell efficiency are yet to be clarified. As a step towards a better understanding of CIGS solar cells, we have analyzed the composition of solar-grade CIGS layers at the atomic-scale by using pulsed laser Atom Probe Tomography (APT). To perform APT analyses on selected GBs site-specific sample preparation was carried out using the Focused Ion Beam lift-out technique. In addition, Electron Back Scattered Diffraction was performed to characterize the structure and misorientation of selected GBs. Using APT, segregation of impurities at the GBs was directly observed. APT data of various types of GBs are presented and discussed with respect to the possible effects on the cell efficiency.

  4. Graphene and Graphene Metamaterials for Terahertz Absorbers

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Pizzocchero, Filippo; Booth, Tim

    2013-01-01

    Graphene, due to the possibility to tune its conductivity, is the promising material for a range of the terahertz (THz) applications, such as tunable reflectors, absorbers, modulators, filters and polarization converters. Subwavelength structuring of graphene in order to form metamaterials allows...... for even more control over the THz waves. In this poster presentation I will show an elegant way to describe the graphene metamaterials and the design of graphene based absorbers. I will also present our recent experimental results on the graphene absorbers characterization....

  5. MATERIAL COMPOSITIONS AND NUMBER DENSITIES FOR NEUTRONICS CALCULATIONS

    International Nuclear Information System (INIS)

    D. A. Thomas

    1996-01-01

    The purpose of this analysis is to calculate the number densities and isotopic weight percentages of the standard materials to be used in the neutronics (criticality and radiation shielding) evaluations by the Waste Package Development Department. The objective of this analysis is to provide material number density information which can be referenced by future neutronics design analyses, such as for those supporting the Conceptual Design Report

  6. Performance evaluation of METAMIC neutron absorber in spent fuel storage rack

    Directory of Open Access Journals (Sweden)

    Kiyoung Kim

    2018-06-01

    Full Text Available High-density spent fuel (SF storage racks have been installed to increase SF pool capacity. In these SF racks, neutron absorber materials were placed between fuel assemblies allowing the storage of fuel assemblies in close proximity to one another. The purpose of the neutron absorber materials is to preclude neutronic coupling between adjacent fuel assemblies and to maintain the fuel in a subcritical storage condition. METAMIC neutron absorber has been used in high-density storage racks. But, neutron absorber materials can be subject to severe conditions including long-term exposure to gamma radiation and neutron radiation. Recently, some of them have experienced degradation, such as white spots on the surface. Under these conditions, the material must continue to serve its intended function of absorbing neutrons. For the first time in Korea, this article uses a neutron attenuation test to examine the performance of METAMIC surveillance coupons. Also, scanning electron microscope analysis was carried out to verify the white spots that were detected on the surface of METAMIC. In the neutron attenuation test, there was no significant sign of boron loss in most of the METAMIC coupons, but the coupon with white spots had relatively less B-10 content than the others. In the scanning electron microscope analysis, corrosion material was detected in all METAMIC coupons. Especially, it was confirmed that the coupon with white spots contains much more corrosion material than the others. Keywords: Blister, Criticality, METAMIC, Neutron Absorber, Neutron Attenuation Test, Scanning Electron Microscope

  7. High-volume use of self-cementing spray dry absorber material for structural applications

    Science.gov (United States)

    Riley, Charles E.

    Spray dry absorber (SDA) material, or spray dryer ash, is a byproduct of energy generation by coal combustion and sulfur emissions controls. Like any resource, it ought to be used to its fullest potential offsetting as many of the negative environmental impacts of coal combustion as possible throughout its lifecycle. Its cementitious and pozzolanic properties suggest it be used to augment or replace another energy and emissions intensive product: Portland cement. There is excellent potential for spray dryer ash to be used beneficially in structural applications, which will offset CO2 emissions due to Portland cement production, divert landfill waste by further utilizing a plentiful coal combustion by-product, and create more durable and sustainable structures. The research into beneficial use applications for SDA material is relatively undeveloped and the material is highly underutilized. This dissertation explored a specific self-cementing spray dryer ash for use as a binder in structural materials. Strength and stiffness properties of hydrated spray dryer ash mortars were improved by chemical activation with Portland cement and reinforcement with polymer fibers from automobile tire recycling. Portland cement at additions of five percent of the cementitious material was found to function effectively as an activating agent for spray dryer ash and had a significant impact on the hardened properties. The recycled polymer fibers improved the ductility and toughness of the material in all cases and increased the compressive strength of weak matrix materials like the pure hydrated ash. The resulting hardened materials exhibited useful properties that were sufficient to suggest that they be used in structural applications such as concrete, masonry block, or as a hydraulic cement binder. While the long-term performance characteristics remain to be investigated, from an embodied-energy and carbon emissions standpoint the material investigated here is far superior to

  8. Directed Atom-by-Atom Assembly of Dopants in Silicon.

    Science.gov (United States)

    Hudak, Bethany M; Song, Jiaming; Sims, Hunter; Troparevsky, M Claudia; Humble, Travis S; Pantelides, Sokrates T; Snijders, Paul C; Lupini, Andrew R

    2018-05-17

    The ability to controllably position single atoms inside materials is key for the ultimate fabrication of devices with functionalities governed by atomic-scale properties. Single bismuth dopant atoms in silicon provide an ideal case study in view of proposals for single-dopant quantum bits. However, bismuth is the least soluble pnictogen in silicon, meaning that the dopant atoms tend to migrate out of position during sample growth. Here, we demonstrate epitaxial growth of thin silicon films doped with bismuth. We use atomic-resolution aberration-corrected imaging to view the as-grown dopant distribution and then to controllably position single dopants inside the film. Atomic-scale quantum-mechanical calculations corroborate the experimental findings. These results indicate that the scanning transmission electron microscope is of particular interest for assembling functional materials atom-by-atom because it offers both real-time monitoring and atom manipulation. We envision electron-beam manipulation of atoms inside materials as an achievable route to controllable assembly of structures of individual dopants.

  9. Thermal Performance Analysis of Staging Effect of Solar Thermal Absorber with Cross Design

    International Nuclear Information System (INIS)

    Amir Abdul Razak; Zafri Azran Abdul Majid; Mohd Hafidz Ruslan; Kamaruzzaman Sopian

    2015-01-01

    The type and shape of solar thermal absorber materials will impact on the operating temperature and thermal energy storage effect of a solar air thermal collector. For a standard flat-plate design, energy gain can be increased by expanding the thermal absorber area along the collector plane, subject to area limitation. This paper focuses on the staging effect of a metal hollow square rod absorber of aluminium, stainless steel, and a combination of the two with a cross design, for the heat gain and temperature characteristics of a solar air collector. Experiments were carried out with three cross design set-ups, with 30 minutes of heating and cooling, phase, respectively, under 485 W/ m 2 solar irradiance value, and at a constant air speed at 0.38 m/ s. One set aluminium set-up delivered the highest output temperature of 41.8 degree Celsius, followed by two-sets aluminium and one aluminium set + one stainless steel set at 39.3 and 38.2 degree Celsius, respectively. The lowest peak temperature is recorded on three sets of the aluminium absorber at 35 degree Celsius. The bi-metallic set-up performed better than the two aluminium set-up where each set-up obtained a temperature drop against heat gain gradient value of -0.4186 degree Celsius/ W and -0.4917 degree Celsius/ W, respectively. Results concluded that by increasing the number of sets, the volume and surface areas of the absorber material are also increased, and lead to a decrease in peak temperature output for each increase of sets. (author)

  10. High intensity 5 eV cw laser substained O-atom exposure facility for material degradation studies

    International Nuclear Information System (INIS)

    Cross, J.B.; Spangler, L.H.; Hoffbauer, M.A.; Archuleta, F.A.

    1986-01-01

    An atomic oxygen exposure facility has been developed for studies of material degradation. The goal of these studies is to provide design criteria and information for the manufacture of long life (20 to 30 years) construction material for use in low earth orbit. The studies that are being undertaken using the facility will provide (1) absolute reaction cross sections for use in engineering design problems, (2) formulations of reaction mechanisms for use in selection of suitable existing materials and design of new more resistant ones, and (3) calibration of flight hardware (mass spectrometers, etc.) in order to directly relate experiments performed in low earth orbit to ground based investigations. The facility consists of (1) a cw laser sustained discharge source of O-atoms having a variable energy up to 5 eV and an intensity of between 10 15 -10 17 O-atoms s -1 cm -2 , (2) an atomic beam formation and diagnostics system consisting of various stages of differential pumping, mass spectrometer detector and time-of-flight analysis, (3) a spinning rotor viscometer for absolute O-atom flux measurements, and (4) provision for using the system for calibration of flight instruments. 15 refs., 10 figs

  11. Maximum compression of Z-pinch in a gas with high atomic number

    International Nuclear Information System (INIS)

    Gerusov, A.V.

    1989-01-01

    An ideal system of equations with shock heating is used for describing of a Z pinch in a gas with high atomic number. In this case equations do not depend from the installation parameters. The approximate simple solution of such a system is presented. Numerical calculations of equations with radiative cooling and various dissipative effects have determined the employment conditions of ideal magnetohydrodynamic equation system. 10 refs

  12. Thin films of copper antimony sulfide: A photovoltaic absorber material

    Energy Technology Data Exchange (ETDEWEB)

    Ornelas-Acosta, R.E. [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66450 (Mexico); Shaji, S. [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66450 (Mexico); Universidad Autónoma de Nuevo León-CIIDIT, Apodaca, Nuevo León (Mexico); Avellaneda, D.; Castillo, G.A.; Das Roy, T.K. [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66450 (Mexico); Krishnan, B., E-mail: kbindu_k@yahoo.com [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, San Nicolás de los Garza, Nuevo León 66450 (Mexico); Universidad Autónoma de Nuevo León-CIIDIT, Apodaca, Nuevo León (Mexico)

    2015-01-15

    Highlights: • CuSbS{sub 2} thin films were prepared by heating Sb{sub 2}S{sub 3}/Cu layers. • Analyzed the structure, composition, optical, and electrical properties. • PV structures: glass/SnO{sub 2}:F/n-CdS/p-CuSbS{sub 2}/C/Ag were formed at different conditions. • The PV parameters (J{sub sc}, V{sub oc}, and FF) were evaluated from the J–V characteristics. • J{sub sc}: 0.52–3.20 mA/cm{sup 2}, V{sub oc}:187–323 mV, FF: 0.27–0.48 were obtained. - Abstract: In this work, we report preparation and characterization of CuSbS{sub 2} thin films by heating glass/Sb{sub 2}S{sub 3}/Cu layers and their use as absorber material in photovoltaic structures: glass/SnO{sub 2}:F/n-CdS/p-CuSbS{sub 2}/C/Ag. The Sb{sub 2}S{sub 3} thin films of 600 nm were prepared by chemical bath deposition on which copper thin films of 50 nm were thermally evaporated, and the glass/Sb{sub 2}S{sub 3}/Cu multilayers were heated in vacuum at different temperatures. X-ray diffraction analysis showed the formation of orthorhombic CuSbS{sub 2} after heating the precursor layers. Studies on identification and chemical state of the elements were done using X-ray photoelectron spectroscopy. The optical band gap of the CuSbS{sub 2} thin films was 1.55 eV and the thin films were photoconductive. The photovoltaic parameters of the devices using CuSbS{sub 2} as absorber and CdS as window layer were evaluated from the J–V curves, yielding J{sub sc}, V{sub oc}, and FF values in the range of 0.52–3.20 mA/cm{sup 2}, 187–323 mV, and 0.27–0.48, respectively, under illumination of AM1.5 radiation.

  13. Design of solar cell materials via soft X-ray spectroscopy

    DEFF Research Database (Denmark)

    Himpsel, F.J.; Cook, P.L.; de la Torre, G.

    2013-01-01

    This overview illustrates how spectroscopy with soft X-rays can assist the development of new materials and new designs for solar cells. The starting point is the general layout of a solar cell, which consists of a light absorber sandwiched between an electron donor and an electron acceptor....... There are four relevant energy levels that can be measured with a combination of X-ray absorption spectroscopy and photoelectron spectroscopy, as illustrated for an organic dye as absorber attached to a p-doped diamond film as donor. Systematic measurements of organometallic dyes (phthalocyanines and porphyrins......) as a function of the metal atom are presented for the metal 2p and N 1s absorption edges. In combination with density functional theory one can discern trends that are useful for tailoring absorber molecules. A customized porphyrin molecule is investigated that combines an absorber with a donor and a linker...

  14. Structurally uniform and atomically precise carbon nanostructures

    Science.gov (United States)

    Segawa, Yasutomo; Ito, Hideto; Itami, Kenichiro

    2016-01-01

    Nanometre-sized carbon materials consisting of benzene units oriented in unique geometric patterns, hereafter named nanocarbons, conduct electricity, absorb and emit light, and exhibit interesting magnetic properties. Spherical fullerene C60, cylindrical carbon nanotubes and sheet-like graphene are representative forms of nanocarbons, and theoretical simulations have predicted several exotic 3D nanocarbon structures. At present, synthetic routes to nanocarbons mainly lead to mixtures of molecules with a range of different structures and properties, which cannot be easily separated or refined into pure forms. Some researchers believe that it is impossible to synthesize these materials in a precise manner. Obtaining ‘pure’ nanocarbons is a great challenge in the field of nanocarbon science, and the construction of structurally uniform nanocarbons, ideally as single molecules, is crucial for the development of functional materials in nanotechnology, electronics, optics and biomedical applications. This Review highlights the organic chemistry approach — more specifically, bottom-up construction with atomic precision — that is currently the most promising strategy towards this end.

  15. Device for absorbing seismic effects on buildings

    International Nuclear Information System (INIS)

    Xercavins, Pierre; Pompei, Michel.

    1979-01-01

    Device for absorbing seismic effects. The construction or structure to be protected rests on its foundations through at least one footing formed of a stack of metal plates interlinked by layers of adhesive material, over at least a part of their extent, this material being an elastomer that can distort, characterized in that at least part of the area of some metal plates works in association with components which are able to absorb at least some of the energy resulting from friction during the relative movements of the metal plates against the distortion of the elastomer [fr

  16. Perspective: Toward "synthesis by design": Exploring atomic correlations during inorganic materials synthesis

    Science.gov (United States)

    Soderholm, L.; Mitchell, J. F.

    2016-05-01

    Synthesis of inorganic extended solids is a critical starting point from which real-world functional materials and their consequent technologies originate. However, unlike the rich mechanistic foundation of organic synthesis, with its underlying rules of assembly (e.g., functional groups and their reactivities), the synthesis of inorganic materials lacks an underpinning of such robust organizing principles. In the latter case, any such rules must account for the diversity of chemical species and bonding motifs inherent to inorganic materials and the potential impact of mass transport on kinetics, among other considerations. Without such assembly rules, there is less understanding, less predictive power, and ultimately less control of properties. Despite such hurdles, developing a mechanistic understanding for synthesis of inorganic extended solids would dramatically impact the range of new material discoveries and resulting new functionalities, warranting a broad call to explore what is possible. Here we discuss our recent approaches toward a mechanistic framework for the synthesis of bulk inorganic extended solids, in which either embryonic atomic correlations or fully developed phases in solutions or melts can be identified and tracked during product selection and crystallization. The approach hinges on the application of high-energy x-rays, with their penetrating power and large Q-range, to explore reaction pathways in situ. We illustrate this process using two examples: directed assembly of Zr clusters in aqueous solution and total phase awareness during crystallization from K-Cu-S melts. These examples provide a glimpse of what we see as a larger vision, in which large scale simulations, data-driven science, and in situ studies of atomic correlations combine to accelerate materials discovery and synthesis, based on the assembly of well-defined, prenucleated atomic correlations.

  17. Theoretical investigation of the use of nanocages with an adsorbed halogen atom as anode materials in metal-ion batteries.

    Science.gov (United States)

    Razavi, Razieh; Abrishamifar, Seyyed Milad; Rajaei, Gholamreza Ebrahimzadeh; Kahkha, Mohammad Reza Rezaei; Najafi, Meysam

    2018-02-21

    The applicability of C 44 , B 22 N 22 , Ge 44 , and Al 22 P 22 nanocages, as well as variants of those nanocages with an adsorbed halogen atom, as high-performance anode materials in Li-ion, Na-ion, and K-ion batteries was investigated theoretically via density functional theory. The results obtained indicate that, among the nanocages with no adsorbed halogen atom, Al 22 P 22 would be the best candidate for a novel anode material for use in metal-ion batteries. Calculations also suggest that K-ion batteries which utilize these nanocages as anode materials would give better performance and would yield higher cell voltages than the corresponding Li-ion and Na-ion batteries with nanocage-based anodes. Also, the results for the nanocages with an adsorbed halogen atom imply that employing them as anode materials would lead to higher cell voltages and better metal-ion battery performance than if the nanocages with no adsorbed halogen atom were to be used as anode materials instead. Results further implied that nanocages with an adsorbed F atom would give higher cell voltages and better battery performance than nanocages with an adsorbed Cl or Br atom. We were ultimately able to conclude that a K-ion battery that utilized Al 21 P 22 with an adsorbed F atom as its anode material would afford the best metal-ion battery performance; we therefore propose this as a novel highly efficient metal-ion battery. Graphical abstract The results of a theoretical investigation indicated that Al 22 P 22 is a better candidate for a high-performance anode material in metal-ion batteries than Ge 44 is. Calculations also showed that K-ion batteries with nanocage-based anodes would produce higher cell voltages and perform better than the equivalent Li-ion and Na-ion batteries with nanocage-based anodes, and that anodes based on nanocages with an adsorbed F atom would perform better than anodes based on nanocages with an adsorbed Cl or Br atom.

  18. Study of effective atomic number of breast tissues determined using the elastic to inelastic scattering ratio

    International Nuclear Information System (INIS)

    Antoniassi, M.; Conceicao, A.L.C.; Poletti, M.E.

    2011-01-01

    In this work we have measured Compton and Rayleigh scattering radiation from normal (adipose and fibroglandular), benign (fibroadenoma) and malignant (ductal carcinoma) breast tissues using a monoenergetic beam of 17.44 keV and a scattering angle of 90 o (x=0.99 A -1 ). A practical method using the area of Rayleigh and Compton scattering was used for determining the effective atomic number (Z eff ) of the samples, being validated through measurements of several reference materials. The results show that there are differences in the distributions of Z eff of breast tissues, which are mainly related to the elemental composition of carbon (Z=6) and oxygen (Z=8) of each tissue type. The results suggest that is possible to use the method to characterize the breast tissues permitting study histological features of the breast tissues related to their elemental composition.

  19. Study of effective atomic number of breast tissues determined using the elastic to inelastic scattering ratio

    Science.gov (United States)

    Antoniassi, M.; Conceição, A. L. C.; Poletti, M. E.

    2011-10-01

    In this work we have measured Compton and Rayleigh scattering radiation from normal (adipose and fibroglandular), benign (fibroadenoma) and malignant (ductal carcinoma) breast tissues using a monoenergetic beam of 17.44 keV and a scattering angle of 90° ( x=0.99 Å -1). A practical method using the area of Rayleigh and Compton scattering was used for determining the effective atomic number ( Zeff) of the samples, being validated through measurements of several reference materials. The results show that there are differences in the distributions of Zeff of breast tissues, which are mainly related to the elemental composition of carbon ( Z=6) and oxygen ( Z=8) of each tissue type. The results suggest that is possible to use the method to characterize the breast tissues permitting study histological features of the breast tissues related to their elemental composition.

  20. Absorbable magnesium-based stent: physiological factors to consider for in vitro degradation assessments

    OpenAIRE

    Wang, Juan; Smith, Christopher E.; Sankar, Jagannathan; Yun, Yeoheung; Huang, Nan

    2015-01-01

    Absorbable metals have been widely tested in various in vitro settings using cells to evaluate their possible suitability as an implant material. However, there exists a gap between in vivo and in vitro test results for absorbable materials. A lot of traditional in vitro assessments for permanent materials are no longer applicable to absorbable metallic implants. A key step is to identify and test the relevant microenvironment and parameters in test systems, which should be adapted according ...

  1. The ways for increasing the technical capabilities of antiseismic hydraulic shock absorbers

    International Nuclear Information System (INIS)

    Kaznovskij, S.P.; Lenskij, V.S.; Plyaskov, A.S.

    1986-01-01

    Basic achievements in a sphere of production of a new type of atomic power equipment-hydraulic shock absorbers-intended for NPP antiseismic fixation of pipelines are considered in short. In designing the new shock absorbers emphasis is placed on maximum unification of the most labor-consuming units, introduction of promising technological processes for mechanical treatment, optimization of the type and dimensional series, impovement of operational characteristics and simplification of assemblying and preparation for putting into operation

  2. Laser-induced fluorescence line narrowing in atomic vapors

    International Nuclear Information System (INIS)

    Meier, T.; Schuessler, H.A.

    1983-01-01

    The use of highly monochromatic light allows the selective excitation of atoms in vapors if excitation and detection of the fluorescence is carried out collinearly. The atoms capable of absorbing light then form an atomic beam of well defined velocity along the direction of the laser beam, but no velocity selection occurs perpendicular to it. The potential of the technique for Doppler-free atomic spectroscopy and for the study of excited atom collisions is demonstrated using the Na D 1 line as an example

  3. Experimental observations of electron-backscatter effects from high-atomic-number anodes in large-aspect-ratio, electron-beam diodes

    Energy Technology Data Exchange (ETDEWEB)

    Cooperstein, G; Mosher, D; Stephanakis, S J; Weber, B V; Young, F C [Naval Research Laboratory, Washington, DC (United States); Swanekamp, S B [JAYCOR, Vienna, VA (United States)

    1997-12-31

    Backscattered electrons from anodes with high-atomic-number substrates cause early-time anode-plasma formation from the surface layer leading to faster, more intense electron beam pinching, and lower diode impedance. A simple derivation of Child-Langmuir current from a thin hollow cathode shows the same dependence on the diode aspect ratio as critical current. Using this fact, it is shown that the diode voltage and current follow relativistic Child-Langmuir theory until the anode plasma is formed, and then follows critical current after the beam pinches. With thin hollow cathodes, electron beam pinching can be suppressed at low voltages (< 800 kV) even for high currents and high-atomic-number anodes. Electron beam pinching can also be suppressed at high voltages for low-atomic-number anodes as long as the electron current densities remain below the plasma turn-on threshold. (author). 8 figs., 2 refs.

  4. Does the number of nitrogen atoms have an influence on the conducting properties of diphenylazines? A DFT insight

    International Nuclear Information System (INIS)

    Moral, Monica; Granadino-Roldan, Jose Manuel; Garzon, Andres; Garcia, Gregorio; Fernandez-Gomez, Manuel

    2011-01-01

    Research highlights: → Planarity and aromaticity increase when increasing the number of N atoms. → HOMO → LUMO excitation energy decreases when increasing the number of N atoms. → AEA increases stepwise with the number of N atoms up to 1.51 eV for Ph 2 Tz. → Ph 2 Tz becomes the best candidate of the series in terms of electron injection. → Ph 2 T N3 seems to be the best candidate in terms of electron transport. - Abstract: The present study reports on the variation of some structural and electronic properties related to the electron conductivity for the series of diphenylazines represented by the formula Ph-(C 2+n N 4-n H n )-Ph, n = 0 - 4. Properties such as planarity, aromaticity, HOMO → LUMO excitation energy, electron affinity, LUMO level energy, reorganization energy and electron coupling between neighboring molecules in the crystal were analyzed from a theoretical perspective as a function of the number of nitrogen atoms in the molecular structure. As a result, the planarity, aromaticity and electron affinity increase with the number of N atoms in the central ring while the HOMO → LUMO excitation energy and LUMO levels diminish. It is worth noting that up to n = 3, the frontier orbitals appear delocalized throughout the whole system while for n = 4 the localized character of the LUMO might explain the increase in the reorganization energy and thus the higher difficulty to delocalize the excess of negative charge. Electron coupling between neighboring molecules was also estimated on the basis of the energy splitting in dimer method and the reported crystal structures for some of the studied molecules. Accordingly, the highest |t 12 | value was obtained for Ph 2 T N3 (0.06 eV) while Ph 2 Tz should be the most advantageous candidate of the series in terms of electron injection.

  5. A non-destructive technique for assigning effective atomic number to scientific samples by scattering of 59.54 keV gamma photons

    International Nuclear Information System (INIS)

    Singh, M.P.; Sharma, Amandeep; Singh, Bhajan; Sandhu, B.S.

    2010-01-01

    The objective of present experiment, employing a scattering of 59.54 keV gamma photons, is to assign effective atomic number (Z eff ) to scientific samples (rare earths) of known composition. An HPGe semiconductor detector, placed at 90 o to the incident beam, detects gamma photons scattered from the sample under investigation. The experiment is performed on various elements with atomic number satisfying, 6≤Z≤82, for 59.54 keV incident photons. The intensity ratio of Rayleigh to Compton scattered peaks, corrected for photo-peak efficiency of gamma detector and absorption of photons in the sample and air, is plotted as a function of atomic number and constituted a best fit-curve. From this fit-curve, the respective effective atomic numbers to samples of rare earths are determined. The agreement of measured values of Z eff with theoretical calculations is quite satisfactory.

  6. Effects of composition and microstructure of Pd-Cu-Si metallic glassy alloy thin films on hydrogen absorbing properties

    International Nuclear Information System (INIS)

    Kajita, Susumu; Kohara, Shinji; Onodera, Yohei; Fukunaga, Toshiharu; Matsubara, Eiichiro

    2011-01-01

    Thin films of Pd-Cu-Si metallic glassy alloys for a hydrogen sensor were fabricated by a sputtering method. In order to find out the effect of the composition and the microstructure of them on the hydrogen absorbing property (the H 2 response), the structural parameters based on the short-range order (SRO) were measured. Additionally, the change of the structural parameters with hydrogen absorption was measured, and the correlations of the change with the H 2 response and the hydrogen induced linear expansion coefficient (LEC) were examined. The H 2 response decreased with increases in Si content and the structural parameters. These results can be explained by the positive effects of Si content and the structural parameters on the formation of a trigonal prism which is a structural unit of Pd-based amorphous alloys, and by the negative effect of the trigonal prism on absorbing hydrogen. From the observation of the elongation of the Pd-Pd atomic distance with absorbing hydrogen, H atoms are supposed to occupy the space between Pd atoms. The amount of the change in the Pd-Pd atomic distance showed the positive correlations with the H 2 response and the LEC. (author)

  7. Superradiance of several atoms near a metal nanosphere

    International Nuclear Information System (INIS)

    Protsenko, I E; Uskov, A V

    2015-01-01

    Assuming that the number of emitters (atoms) near a spherical metal nanoparticle is large (more than a few hundred), so that their interaction with each other is strong and sufficient for the emergence of their collective states (Dicke states), it is shown that the nanoparticle accelerates the superradiance of the emitters in a similar way as it accelerates the spontaneous emission of a single emitter. In this case, part of the energy stored by the emitters is absorbed by a nanoparticle, and the rest of the energy is radiated as a superradiance pulse. For the parameters selected in this paper, the energy absorbed by the nanoparticle is approximately equal to the emitted energy. We have found the collective states of the emitters and nanoparticle and have derived expressions for the time dependence of the superradiance pulse power, pulse duration and time delay with respect to the moment of excitation of the emitters. (superradiance)

  8. New atom probe approaches to studying segregation in nanocrystalline materials.

    Science.gov (United States)

    Samudrala, S K; Felfer, P J; Araullo-Peters, V J; Cao, Y; Liao, X Z; Cairney, J M

    2013-09-01

    Atom probe is a technique that is highly suited to the study of nanocrystalline materials. It can provide accurate atomic-scale information about the composition of grain boundaries in three dimensions. In this paper we have analysed the microstructure of a nanocrystalline super-duplex stainless steel prepared by high pressure torsion (HPT). Not all of the grain boundaries in this alloy display obvious segregation, making visualisation of the microstructure challenging. In addition, the grain boundaries present in the atom probe data acquired from this alloy have complex shapes that are curved at the scale of the dataset and the interfacial excess varies considerably over the boundaries, making the accurate characterisation of the distribution of solute challenging using existing analysis techniques. In this paper we present two new data treatment methods that allow the visualisation of boundaries with little or no segregation, the delineation of boundaries for further analysis and the quantitative analysis of Gibbsian interfacial excess at boundaries, including the capability of excess mapping. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Effective atomic number, energy loss and radiation damage studies in some materials commonly used in nuclear applications for heavy charged particles such as H, C, Mg, Fe, Te, Pb and U

    Science.gov (United States)

    Kurudirek, Murat

    2016-05-01

    Commonly used nuclear physics materials such as water, concrete, Pb-glass, paraffin, freon and P 10 gases, some alloys such as brass, bronze, stainless-steel and some scintillators such as anthracene, stilbene and toluene have been investigated with respect to the heavy charged particle interaction as means of projected range and effective atomic number (Zeff) in the energy region 10 keV to 10 MeV. Calculations were performed for heavy ions such as H, C, Mg, Fe, Te, Pb and U. Also, the energy loss and radiation damage were studied using SRIM Monte Carlo code for anthracene for different heavy ions of 100 keV kinetic energy. It has been observed that the variation in Zeff becomes less when the atomic number of the ions increase. Glass-Pb, bronze, brass, stainless-steel and Freon gas were found to vary less than 10% in the energy region 10 keV to 10 MeV. For total proton interaction, discrepancies up to 10% and 18% between two databases namely PSTAR and SRIM were noted in mass stopping power and Zeff of water, respectively. The range calculations resulted with a conclusion that the metal alloys and glass-Pb have lowest values of ranges confirming best shielding against energetic heavy ions whereas freon and P 10 gases have the highest values of ranges in the entire energy region. The simulation results showed that the energy loss (%) to target electrons decreases as the Z of the incident ion increases. Also, it was observed that the radiation damage first increases with Z of the ion and then keeps almost constant for ions with Z≥52.

  10. Automatic kinetic Monte-Carlo modeling for impurity atom diffusion in grain boundary structure of tungsten material

    Directory of Open Access Journals (Sweden)

    Atsushi M. Ito

    2017-08-01

    Full Text Available The diffusion process of hydrogen and helium in plasma-facing material depends on the grain boundary structures. Whether a grain boundary accelerates or limits the diffusion speed of these impurity atoms is not well understood. In the present work, we proposed the automatic modeling of a kinetic Monte-Carlo (KMC simulation to treat an asymmetric grain boundary structure that corresponds to target samples used in fusion material experiments for retention and permeation. In this method, local minimum energy sites and migration paths for impurity atoms in the grain boundary structure are automatically found using localized molecular dynamics. The grain boundary structure was generated with the Voronoi diagram. Consequently, we demonstrate that the KMC simulation for the diffusion process of impurity atoms in the generated grain boundary structure of tungsten material can be performed.

  11. Improvement of analysis precision upon the atomic number and electron density measurement by the dual x-ray CT

    Science.gov (United States)

    Imura, Yukino; Morii, Hisashi; Koike, Akifumi; Okunoyama, Takaharu; Neo, Yoichiro; Mimura, Hidenori; Aoki, Toru

    2010-08-01

    To identify the factor impairing the material identification parameters, which is provided by the dual-energy X-ray computed tomography method using a conventional X-ray tube and a CdTe detector, linear attenuation coefficient was measured by the radioactivity of radio isotopes and compared with theoretical figure. In our study, the atomic number and the electron density is calculated from the linear attenuation coefficient obtained in CT measurement by 64-channel CdTe line detector. To estimate accuracy of CdTe line sensor, it is needed to obtain the linear attenuation coefficient accurately. Using a single detector, the linear attenuation coefficient is verified for accuracy. The energy resolution of CdTe detectors and the method of reconstruction are discussed.

  12. Simulation-based Extraction of Key Material Parameters from Atomic Force Microscopy

    Science.gov (United States)

    Alsafi, Huseen; Peninngton, Gray

    Models for the atomic force microscopy (AFM) tip and sample interaction contain numerous material parameters that are often poorly known. This is especially true when dealing with novel material systems or when imaging samples that are exposed to complicated interactions with the local environment. In this work we use Monte Carlo methods to extract sample material parameters from the experimental AFM analysis of a test sample. The parameterized theoretical model that we use is based on the Virtual Environment for Dynamic AFM (VEDA) [1]. The extracted material parameters are then compared with the accepted values for our test sample. Using this procedure, we suggest a method that can be used to successfully determine unknown material properties in novel and complicated material systems. We acknowledge Fisher Endowment Grant support from the Jess and Mildred Fisher College of Science and Mathematics,Towson University.

  13. Transport of radioactive material. 1994-2002. International Atomic Energy Agency publications

    International Nuclear Information System (INIS)

    2002-10-01

    This document lists all sales publications, IAEA-TECDOC Series, Training Course Series and National Competent Authorities Lists of the International Atomic Energy Agency dealing with the transport of radioactive materials during the period 1994-2002. It gives a short abstract and contents of these issues along with their costs in EURO

  14. Nuclear reactor core having nuclear fuel and composite burnable absorber arranged for power peaking and moderator temperature coefficient control

    International Nuclear Information System (INIS)

    Kapil, S.K.

    1991-01-01

    This patent describes a nuclear reactor core. It comprises a first group of fuel rods containing fissionable material and being free of burnable absorber material; and a second group of fuel rods containing fissionable material and first and second burnable absorber material; the first burnable absorber material being a boron-bearing material which does not contain erbium and the second burnable absorber material being an erbium material; the first and second burnable absorber materials being in the form of an outer coating on the fissionable material, the outer coating being composed of an inner layer of one of the boron-bearing material which does not contain erbium and the erbium material and an outer layer of the other of the boron-bearing material which does not contain erbium and the erbium material

  15. COMPARISON OF ABSORBABLE EXTRA LONG TERM POLY HYDROXY BUTYRATE SUTURE VS NON ABSORBABLE (POLYPROPYLENE SUTURE FOR ABDOMINAL WALL CLOSURE

    Directory of Open Access Journals (Sweden)

    Mallikarjun

    2015-07-01

    Full Text Available PURPOSE: The aim of study is to compare Continuous technique with non - absorbable sutures, Interrupted technique with non - absorbable sutures and Continuous technique with slowly absorbable sutures Focusing mainly on incidence of incisional hernias, burst abdomen, wound infections, chronic wound pain, suture sinus, stitch granuloma, time for rectus closure. METHODOLOGY : Study was conducted for a period of one year on 271 randomized patients with primary elective midline laparotomy in our hospital . patients are divided into group I includes 102 patients with continuous technique using non absorbable polypropylene, group II includes 91 patients with interrupted technique using non absorbable polypropylene and group III includes 78 patients with continuous slowly absorbable polyhydroxybutyrate. RESULTS: No significant difference observed in incidence of wound infections and burst abdomen in all the 3 groups but relatively higher incidence of wound infections in noted our hospital. Incidence of stich granuloma suture sinus and chronic wound pain is more with interrupted technique than continuous technique and are more with non - absor bable suture material. CONCLUSION: Incidence of incisional hernias, suture complications like suture sinus, stitch granuloma can be more effectively reduced with slowly absorbable continuous sutures.

  16. Effective atomic numbers, electron densities and kinetic energy released in matter of vitamins for photon interaction

    Science.gov (United States)

    Shantappa, A.; Hanagodimath, S. M.

    2014-01-01

    Effective atomic numbers, electron densities of some vitamins (Retinol, Riboflavin, Niacin, Biotin, Folic acid, Cobalamin, Phylloquinone and Flavonoids) composed of C, H, O, N, Co, P and S have been calculated for total and partial photon interactions by the direct method for energy range 1 keV-100 GeV by using WinXCOM and kinetic energy released in matter (Kerma) relative to air is calculated in energy range of 1 keV-20 MeV. Change in effective atomic number and electron density with energy is calculated for all photon interactions. Variation of photon mass attenuation coefficients with energy are shown graphically only for total photon interaction. It is observed that change in mass attenuation coefficient with composition of different chemicals is very large below 100 keV and moderate between 100 keV and 10 MeV and negligible above 10 MeV. Behaviour of vitamins is almost indistinguishable except biotin and cobalamin because of large range of atomic numbers from 1(H) to 16 (S) and 1(H) to 27(Co) respectively. K a value shows a peak due to the photoelectric effect around K-absorption edge of high- Z constituent of compound for biotin and cobalamin.

  17. Electrodeposited Ni nanowires-track etched P.E.T. composites as selective solar absorbers

    Science.gov (United States)

    Lukhwa, R.; Sone, B.; Kotsedi, L.; Madjoe, R.; Maaza, M.

    2018-05-01

    This contribution reports on the structural, optical and morphological properties of nanostructured flexible solar-thermal selective absorber composites for low temperature applications. The candidate material in the system is consisting of electrodeposited nickel nano-cylinders embedded in track-etched polyethylene terephthalate (PET) host membrane of pore sizes ranging between 0.3-0.8µm supported by conductive nickel thin film of about 0.5µm. PET were irradiated with 11MeV/u high charged xenon (Xe) ions at normal incidence. The tubular and metallic structure of the nickel nano-cylinders within the insulator polymeric host forms a typical ceramic-metal nano-composite "Cermet". The produced material was characterized by the following techniques: X-ray diffraction (XRD) for structural characterization to determine preferred crystallographic structure, and grain size of the materials; Scanning electron microscopy (SEM) to determine surface morphology, particle size, and visual imaging of distribution of structures on the surface of the substrate; Atomic force microscopy (AFM) to characterize surface roughness, surface morphology, and film thickness, and UV-Vis-NIR spectrophotometer to measure the reflectance, then to determine solar absorption

  18. Eggshell and Bacterial Cellulose Composite Membrane as Absorbent Material in Active Packaging

    Directory of Open Access Journals (Sweden)

    S. Ummartyotin

    2016-01-01

    Full Text Available Bacterial cellulose and eggshell composite was successfully developed. Eggshell was mixed with bacterial cellulose suspension and it was casted as a composite film. CaCO3 derived from eggshell was compared with its commercial availability. It can be noted that good dispersion of eggshell particle was prepared. Eggshell particle was irregular in shape with a variation in size. It existed in bacterial cellulose network. Characterization on composite was focused on thermal and mechanical properties. It showed that flexibility and thermal stability of composite were enhanced. No significant effect of mechanical properties was therefore observed. The thermal stability of composite was stable up to 300°C. The adsorption experiment on water and vegetable oil capacity was performed. The enhancement on adsorption was due to the existence of eggshell in bacterial cellulose composite. It exhibited the potential to be a good candidate for absorbent material in active packaging.

  19. Study of effective atomic number of breast tissues determined using the elastic to inelastic scattering ratio

    Energy Technology Data Exchange (ETDEWEB)

    Antoniassi, M.; Conceicao, A.L.C. [Departamento de Fisica e Matematica, Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo (Brazil); Poletti, M.E., E-mail: poletti@ffclrp.usp.br [Departamento de Fisica e Matematica, Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo (Brazil)

    2011-10-01

    In this work we have measured Compton and Rayleigh scattering radiation from normal (adipose and fibroglandular), benign (fibroadenoma) and malignant (ductal carcinoma) breast tissues using a monoenergetic beam of 17.44 keV and a scattering angle of 90{sup o} (x=0.99 A{sup -1}). A practical method using the area of Rayleigh and Compton scattering was used for determining the effective atomic number (Z{sub eff}) of the samples, being validated through measurements of several reference materials. The results show that there are differences in the distributions of Z{sub eff} of breast tissues, which are mainly related to the elemental composition of carbon (Z=6) and oxygen (Z=8) of each tissue type. The results suggest that is possible to use the method to characterize the breast tissues permitting study histological features of the breast tissues related to their elemental composition.

  20. Computational techniques in tribology and material science at the atomic level

    Science.gov (United States)

    Ferrante, J.; Bozzolo, G. H.

    1992-01-01

    Computations in tribology and material science at the atomic level present considerable difficulties. Computational techniques ranging from first-principles to semi-empirical and their limitations are discussed. Example calculations of metallic surface energies using semi-empirical techniques are presented. Finally, application of the methods to calculation of adhesion and friction are presented.

  1. Method of manufacturing neutron protection materials

    Energy Technology Data Exchange (ETDEWEB)

    Kakibana, Hidetake; Okamoto, Masazane; Fujii, Yasuhiko; Koguchi, Noboru; Takesute, Morito; Miyamatsu, Tokuhisa

    1985-06-22

    To obtain protection materials easily moldable, flexible and capable of minimizing the workers' neutron exposure dose, a fine fiberous assembly is prepared by dispersing compounds of atoms having neutron absorbing performance such as Li or B, for example, finely powderous compounds of LiF or /sup 6/LiF into a solution of spinnable polymer, particularly, polyolefin polymer such as polyethylene in CH/sub 2/Cl and then flash spinning them. The fine fibers are fabricated into mat-like material, blankets, cloths and the likes for use in neutron exposure protection. In the case of neutron irradiation therapy, protection materials of reduced weight, flexible and giving preferred contact with human body can be obtained with ease for protecting the regions other than the lesion area.

  2. Structure and electronic properties of grain boundaries in earth-abundant photovoltaic absorber Cu2ZnSnSe4.

    Science.gov (United States)

    Li, Junwen; Mitzi, David B; Shenoy, Vivek B

    2011-11-22

    We have studied the atomic and electronic structure of Cu(2)ZnSnSe(4) and CuInSe(2) grain boundaries using first-principles calculations. We find that the constituent atoms at the grain boundary in Cu(2)ZnSnSe(4) create localized defect states that promote the recombination of photon-excited electron and hole carriers. In distinct contrast, significantly lower density of defect states is found at the grain boundaries in CuInSe(2), which is consistent with the experimental observation that CuInSe(2) solar cells exhibit high conversion efficiency without the need for deliberate passivation. Our investigations suggest that it is essential to effectively remove these defect states in order to improve the conversion efficiency of solar cells with Cu(2)ZnSnSe(4) as photovoltaic absorber materials. © 2011 American Chemical Society

  3. Recent Development of Advanced Electrode Materials by Atomic Layer Deposition for Electrochemical Energy Storage.

    Science.gov (United States)

    Guan, Cao; Wang, John

    2016-10-01

    Electrode materials play a decisive role in almost all electrochemical energy storage devices, determining their overall performance. Proper selection, design and fabrication of electrode materials have thus been regarded as one of the most critical steps in achieving high electrochemical energy storage performance. As an advanced nanotechnology for thin films and surfaces with conformal interfacial features and well controllable deposition thickness, atomic layer deposition (ALD) has been successfully developed for deposition and surface modification of electrode materials, where there are considerable issues of interfacial and surface chemistry at atomic and nanometer scale. In addition, ALD has shown great potential in construction of novel nanostructured active materials that otherwise can be hardly obtained by other processing techniques, such as those solution-based processing and chemical vapor deposition (CVD) techniques. This review focuses on the recent development of ALD for the design and delivery of advanced electrode materials in electrochemical energy storage devices, where typical examples will be highlighted and analyzed, and the merits and challenges of ALD for applications in energy storage will also be discussed.

  4. Electrical Conductivity of Gamma Irradiated Aqueous Urea Solution and its Application for Determination of Absorbed Radiation Dose; Sife-Eldeen Dosimeter

    International Nuclear Information System (INIS)

    Sife- Eldeen, Kh.A.

    2008-01-01

    In This Study, the radiation induced electrical conductivity (RIC) of aqueous urea solutions was investigated after gamma radiolysis. It was found that the RIC depends on preirradiation urea concentration, absorbed radiation dose and storage time. At the same absorbed dose, RIC increases as preirradiation urea concentration increases. The RIC change of aqueous urea solutions reaches a maximum value at 3.5 M aqueous urea solutions. RIC of 0.133 and 3.5 M aqueous urea solutions as a function of dose, have been investigated in the range between 2.18 and 119.4 kGy. RIC of the 0.133 and 3.5 M aqueous urea solutions increased linearly with increasing dose (R 2 =0.9963, 0.9972 respectively). The calibration factors was found to be 2.1448 and 9.53 μS/kGy for sets with 0.133 and 3.5 M urea respectively .The coefficient of variation CV %, associated with RIC measurement of 3.5 M aqueous urea solution as a function of absorbed radiation dose was found to be 1.8025% and the uncertainty was found to be 3.6 % and 5.4 % for 95 % and 99 % confidence levels, respectively. The effective atomic number of 3.5 M aqueous urea solutions is 6.58, which indicates tissue equivalency of this system. The RIC values of 3.5 M aqueous urea solutions were found to be relatively stable over storage period of three weeks at 0 degree C. Accordingly, this system could be considered as a promising radiation-sensitive material for dosimetry of gamma rays in both technical and research fields

  5. Selective solar absorber emittance measurement at elevated temperature

    Science.gov (United States)

    Giraud, Philémon; Braillon, Julien; Raccurt, Olivier

    2017-06-01

    Durability of solar components for CSP (Concentrated Solar Power Plant) technologies is a key point to lower cost and ensure their large deployment. These technologies concentrated the solar radiation by means of mirrors on a receiver tube where it is collected as thermal energy. The absorbers are submitted to strong environmental constraints and the degradation of their optical properties (emittance and solar absorbance) have a direct impact on performance. The characterization of a material in such condition is complicated and requires advanced apparatuses, and different measurement methods exist for the determination of the two quantities of relevance regarding an absorber, which are its emittance and its solar absorbance. The objective is to develop new optical equipment for measure the emittance of this solar absorber at elevated temperature. In this paper, we present an optical bench developed for emittance measurement on absorbers is conditions of use. Results will be shown, with a discussion of some factors of influence over this measurement and how to control them.

  6. OrbusNeich fully absorbable coronary stent platform incorporating dual partitioned coatings.

    Science.gov (United States)

    Cottone, Robert J; Thatcher, G Lawrence; Parker, Sherry P; Hanks, Laurence; Kujawa, David A; Rowland, Stephen M; Costa, Marco; Schwartz, Robert S; Onuma, Yoshinobu

    2009-12-15

    The field of stent based tissue engineering continues to revolutionise modern medicine by designing novel materials to restore vascular tissue function. Accordingly, the following discussion examines a novel, absorbable, polymeric scaffold engineered in combination with dual therapeutic coating, enabling locally administered temporary scaffolding in the coronary arteries for long term vascular patency and repair. This coronary stent platform consists of an absorbable polymeric material stent structure that incorporates a dual partitioned coating, by means of pro-healing EPC (endothelial progenitor cell) capture technology allowing for rapid endothelial coverage, and an absorbable polymer matrix with sustained elution of sirolimus, a drug controlling neointimal proliferation. This paper provides a brief overview of the various innovations developed by OrbusNeich to create this fully absorbable coronary device platform.

  7. Rice straw-wood particle composite for sound absorbing wooden construction materials.

    Science.gov (United States)

    Yang, Han-Seung; Kim, Dae-Jun; Kim, Hyun-Joong

    2003-01-01

    In this study, rice straw-wood particle composite boards were manufactured as insulation boards using the method used in the wood-based panel industry. The raw material, rice straw, was chosen because of its availability. The manufacturing parameters were: a specific gravity of 0.4, 0.6, and 0.8, and a rice straw content (10/90, 20/80, and 30/70 weight of rice straw/wood particle) of 10, 20, and 30 wt.%. A commercial urea-formaldehyde adhesive was used as the composite binder, to achieve 140-290 psi of bending modulus of rupture (MOR) with 0.4 specific gravity, 700-900 psi of bending MOR with 0.6 specific gravity, and 1400-2900 psi of bending MOR with a 0.8 specific gravity. All of the composite boards were superior to insulation board in strength. Width and length of the rice straw particle did not affect the bending MOR. The composite boards made from a random cutting of rice straw and wood particles were the best and recommended for manufacturing processes. Sound absorption coefficients of the 0.4 and 0.6 specific gravity boards were higher than the other wood-based materials. The recommended properties of the rice straw-wood particle composite boards are described, to absorb noises, preserve the temperature of indoor living spaces, and to be able to partially or completely substitute for wood particleboard and insulation board in wooden constructions.

  8. Absorbable magnesium-based stent: physiological factors to consider for in vitro degradation assessments.

    Science.gov (United States)

    Wang, Juan; Smith, Christopher E; Sankar, Jagannathan; Yun, Yeoheung; Huang, Nan

    2015-03-01

    Absorbable metals have been widely tested in various in vitro settings using cells to evaluate their possible suitability as an implant material. However, there exists a gap between in vivo and in vitro test results for absorbable materials. A lot of traditional in vitro assessments for permanent materials are no longer applicable to absorbable metallic implants. A key step is to identify and test the relevant microenvironment and parameters in test systems, which should be adapted according to the specific application. New test methods are necessary to reduce the difference between in vivo and in vitro test results and provide more accurate information to better understand absorbable metallic implants. In this investigative review, we strive to summarize the latest test methods for characterizing absorbable magnesium-based stent for bioabsorption/biodegradation behavior in the mimicking vascular environments. Also, this article comprehensively discusses the direction of test standardization for absorbable stents to paint a more accurate picture of the in vivo condition around implants to determine the most important parameters and their dynamic interactions.

  9. Truly Absorbed Microbial Protein Synthesis, Rumen Bypass Protein, Endogenous Protein, and Total Metabolizable Protein from Starchy and Protein-Rich Raw Materials

    NARCIS (Netherlands)

    Parand, Ehsan; Vakili, Alireza; Mesgaran, Mohsen Danesh; Duinkerken, Van Gert; Yu, Peiqiang

    2015-01-01

    This study was carried out to measure truly absorbed microbial protein synthesis, rumen bypass protein, and endogenous protein loss, as well as total metabolizable protein, from starchy and protein-rich raw feed materials with model comparisons. Predictions by the DVE2010 system as a more

  10. Inkjet Printing and Ebeam Sintering Approach to Fabrication of GHz Meta material Absorber

    International Nuclear Information System (INIS)

    Park, J. W.; Kim, Y. J.; Lee, Y. P.; Park, I. S.; Kang, J. H.; Lim, Jongwoo; Kim, Jonghee; Kim, Hyotae

    2013-01-01

    Metamaterial absorber structure of GHz range is fabricated by inkjet printing and e-beam sintering. The inkjet printing is of interest, which give the easier and quicker way to fabricate large scale metamaterials than the approaches by the lithographic process, Furthermore it is more suitable to make flexible electronics, which has yet been great technologic trend. Usual post process of inkjet printing is the sintering to ensure solvent-free from the printed pattern and to its better conductivity comparable to the ordinary vacuum deposition process. E-beam irradiation sintering of the pattern is promising because it is inherently local and low temperature process. The main procedure of metamaterials fabrication is printing a resonator structure with lossy metal such as Ag or Au. We designed two types of Ag based multiband absorber which are double and quadruple bands. Those adsorber patterns are printed on polyimide substrate with commercially available Ag ink (DGP 40LT-15C, 25C). The absorbance performance of fabricated metamaterials is characterized by Hewlett-Packard E836B network analyzer in microwave anechoic chamber. The conductivity enhancement after e-beam or other sintering process is checked by measuring sheet resistance. The absorbance of the fabricated metamaterial is measured around 60% for the types designed. The absorbance is not high enough to practical use, which is attributed to low conductivity of the printed pattern. The spectrum shows, however, quite interesting large broadness, which come in the interval between each pack absorbance, witch needs further study. Though the extent of its effectiveness of inkjet printing in metamaterials needs more experimental studies, the demonstrated capability of quick and large area fabrication to flexible substrate is excellent

  11. Calculation of the number of atoms displaced during the irradiation of monolayer graphene

    International Nuclear Information System (INIS)

    Daniel Codorniu Pujals; Yuri Aguilera Corrales; Francesco Baldassarre

    2011-01-01

    The irradiation of monolayer graphene, combined with chemical functionalization, could be an effective method for modifying its electronic structure and for achieving specific physical properties adjusted to different applications. A difficulty arising during planning and studying the irradiation in this system is that many of the models of interaction of the radiation with the substance cannot be applied to the two-dimensional structure of graphene. In particular, the mathematical expressions available to calculate the number of atoms displaced during the bombardment with particles can be applied only to 3D isotropic solids. In the present work, an alternative analytic expression is presented for the irradiation of graphene with heavy ions or with protons and other light charged particles. The expression was obtained on the basis of the classic theory of dispersion, using a Coulomb potential for the light charged particles and one of Inverse Square for heavy ions. For medium values of the energy of the incident particle a decreasing dependence of the number of displaced atoms with energy is obtained. This behavior, related with the two-dimensional structure of the target, had been observed in other authors' works using computational simulation. (author)

  12. The Materials Chemistry of Atomic Oxygen with Applications to Anisotropic Etching of Submicron Structures in Microelectronics and the Surface Chemistry Engineering of Porous Solids

    Science.gov (United States)

    Koontz, Steve L.; Leger, Lubert J.; Wu, Corina; Cross, Jon B.; Jurgensen, Charles W.

    1994-01-01

    Neutral atomic oxygen is the most abundant component of the ionospheric plasma in the low Earth orbit environment (LEO; 200 to 700 kilometers altitude) and can produce significant degradation of some spacecraft materials. In order to produce a more complete understanding of the materials chemistry of atomic oxygen, the chemistry and physics of O-atom interactions with materials were determined in three radically different environments: (1) The Space Shuttle cargo bay in low Earth orbit (the EOIM-3 space flight experiment), (2) a high-velocity neutral atom beam system (HVAB) at Los Alamos National Laboratory (LANL), and (3) a microwave-plasma flowing-discharge system at JSC. The Space Shuttle and the high velocity atom beam systems produce atom-surface collision energies ranging from 0.1 to 7 eV (hyperthermal atoms) under high-vacuum conditions, while the flowing discharge system produces a 0.065 eV surface collision energy at a total pressure of 2 Torr. Data obtained in the three different O-atom environments referred to above show that the rate of O-atom reaction with polymeric materials is strongly dependent on atom kinetic energy, obeying a reactive scattering law which suggests that atom kinetic energy is directly available for overcoming activation barriers in the reaction. General relationships between polymer reactivity with O atoms and polymer composition and molecular structure have been determined. In addition, vacuum ultraviolet photochemical effects have been shown to dominate the reaction of O atoms with fluorocarbon polymers. Finally, studies of the materials chemistry of O atoms have produced results which may be of interest to technologists outside the aerospace industry. Atomic oxygen 'spin-off' or 'dual use' technologies in the areas of anisotropic etching in microelectronic materials and device processing, as well as surface chemistry engineering of porous solid materials are described.

  13. Absorbed dose determination in external beam radiotherapy. An international code of practice for dosimetry based on standards of absorbed dose to water

    International Nuclear Information System (INIS)

    2000-01-01

    The International Atomic Energy Agency published in 1987 an International Code of Practice entitled 'Absorbed Dose Determination in Photon and Electron Beams' (IAEA Technical Reports Series No. 277 (TRS-277)), recommending procedures to obtain the absorbed dose in water from measurements made with an ionization chamber in external beam radiotherapy. A second edition of TRS-277 was published in 1997 updating the dosimetry of photon beams, mainly kilovoltage X rays. Another International Code of Practice for radiotherapy dosimetry entitled 'The Use of Plane-Parallel Ionization Chambers in High Energy Electron and Photon Beams' (IAEA Technical Reports Series No. 381 (TRS-381)) was published in 1997 to further update TRS-277 and complement it with respect to the area of parallel-plate ionization chambers. Both codes have proven extremely valuable for users involved in the dosimetry of the radiation beams used in radiotherapy. In TRS-277 the calibration of the ionization chambers was based on primary standards of air kerma; this procedure was also used in TRS-381, but the new trend of calibrating ionization chambers directly in a water phantom in terms of absorbed dose to water was introduced. The development of primary standards of absorbed dose to water for high energy photon and electron beams, and improvements in radiation dosimetry concepts, offer the possibility of reducing the uncertainty in the dosimetry of radiotherapy beams. The dosimetry of kilovoltage X rays, as well as that of proton and heavy ion beams, interest in which has grown considerably in recent years, can also be based on these standards. Thus a coherent dosimetry system based on standards of absorbed dose to water is possible for practically all radiotherapy beams. Many Primary Standard Dosimetry Laboratories (PSDLs) already provide calibrations in terms of absorbed dose to water at the radiation quality of 60 Co gamma rays. Some laboratories have extended calibrations to high energy photon and

  14. Review of Plasmonic Nanocomposite Metamaterial Absorber

    Directory of Open Access Journals (Sweden)

    Mehdi Keshavarz Hedayati

    2014-02-01

    Full Text Available Plasmonic metamaterials are artificial materials typically composed of noble metals in which the features of photonics and electronics are linked by coupling photons to conduction electrons of metal (known as surface plasmon. These rationally designed structures have spurred interest noticeably since they demonstrate some fascinating properties which are unattainable with naturally occurring materials. Complete absorption of light is one of the recent exotic properties of plasmonic metamaterials which has broadened its application area considerably. This is realized by designing a medium whose impedance matches that of free space while being opaque. If such a medium is filled with some lossy medium, the resulting structure can absorb light totally in a sharp or broad frequency range. Although several types of metamaterials perfect absorber have been demonstrated so far, in the current paper we overview (and focus on perfect absorbers based on nanocomposites where the total thickness is a few tens of nanometer and the absorption band is broad, tunable and insensitive to the angle of incidence. The nanocomposites consist of metal nanoparticles embedded in a dielectric matrix with a high filling factor close to the percolation threshold. The filling factor can be tailored by the vapor phase co-deposition of the metallic and dielectric components. In addition, novel wet chemical approaches are discussed which are bio-inspired or involve synthesis within levitating Leidenfrost drops, for instance. Moreover, theoretical considerations, optical properties, and potential application of perfect absorbers will be presented.

  15. Correlations in the three-dimensional Lyman-alpha forest contaminated by high column density absorbers

    Science.gov (United States)

    Rogers, Keir K.; Bird, Simeon; Peiris, Hiranya V.; Pontzen, Andrew; Font-Ribera, Andreu; Leistedt, Boris

    2018-05-01

    Correlations measured in three dimensions in the Lyman-alpha forest are contaminated by the presence of the damping wings of high column density (HCD) absorbing systems of neutral hydrogen (H I; having column densities N(H I) > 1.6 × 10^{17} atoms cm^{-2}), which extend significantly beyond the redshift-space location of the absorber. We measure this effect as a function of the column density of the HCD absorbers and redshift by measuring three-dimensional (3D) flux power spectra in cosmological hydrodynamical simulations from the Illustris project. Survey pipelines exclude regions containing the largest damping wings. We find that, even after this procedure, there is a scale-dependent correction to the 3D Lyman-alpha forest flux power spectrum from residual contamination. We model this residual using a simple physical model of the HCD absorbers as linearly biased tracers of the matter density distribution, convolved with their Voigt profiles and integrated over the column density distribution function. We recommend the use of this model over existing models used in data analysis, which approximate the damping wings as top-hats and so miss shape information in the extended wings. The simple `linear Voigt model' is statistically consistent with our simulation results for a mock residual contamination up to small scales (|k| account for the effect of the highest column density absorbers on the smallest scales (e.g. |k| > 0.4 h Mpc^{-1} for small damped Lyman-alpha absorbers; HCD absorbers with N(H I) ˜ 10^{21} atoms cm^{-2}). However, these systems are in any case preferentially removed from survey data. Our model is appropriate for an accurate analysis of the baryon acoustic oscillations feature. It is additionally essential for reconstructing the full shape of the 3D flux power spectrum.

  16. Characterization of load dependent creep behavior in medically relevant absorbable polymers.

    Science.gov (United States)

    Dreher, Maureen L; Nagaraja, Srinidhi; Bui, Hieu; Hong, Danny

    2014-01-01

    While synthetic absorbable polymers have a substantial history of use in medical devices, their use is expanding and becoming more prevalent for devices where long term loading and structural support is required. In addition, there is evidence that current absorbable medical devices may experience permanent deformations, warping (out of plane twisting), and geometric changes in vivo. For clinical indications with long term loading or structural support requirements, understanding the material's viscoelastic properties becomes increasingly important whereas these properties have not been used historically as preclinical indications of performance or design considerations. In this study we measured the static creep, creep recovery and cyclic creep responses of common medically relevant absorbable materials (i.e., poly(l-lactide, PLLA) and poly(l-co-glycolide, PLGA) over a range of physiologically relevant loading magnitudes. The results indicate that both PLLA and PLGA exhibit creep behavior and failure at loads significantly less than the yield or ultimate properties of the material and that significant material specific responses to loading exist. In addition, we identified a strong correlation between the extent of creep in the material and its crystallinity. Results of the study provide new information on the creep behavior of PLLA and PLGA and support the use of viscoelastic properties of absorbable polymers as part of the material selection process. © 2013 Published by Elsevier Ltd.

  17. A chiral microwave absorbing absorbent of Fe–CoNiP coated on spirulina

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yonggang, E-mail: xuyonggang221@163.com [Science and Technology on Electromagnetic Scattering Laboratory, Shanghai, 200438 (China); Yuan, Liming [Science and Technology on Electromagnetic Scattering Laboratory, Shanghai, 200438 (China); Zhang, Deyuan [School of Mechanical Engineering and Automation, Beihang University, Beijing, 100191 (China)

    2015-11-15

    A chiral bio-absorbent of Fe–CoNiP coated on the spirulina was fabricated by the electroless and chemical vapor decomposition. The scanning electron microscopy (SEM) was used to evaluate the spirulina cells particle morphology. X-ray diffraction (XRD) patterns were done to analyze the particle crystal grain structure. The permittivity and permeability was measured by a vector network analyzer in frequency 8–18 GHz, and the reflection loss (RL) was calculated. The results showed the carbonyl iron particles (CIPs) and CoNiP were bonded to the spirulina surface, the permittivity and permeability could be enlarged as Fe films coated on the particles compared with the CoNiP spirulina, it was attributed to the excellent electromagnetic property of CIPs. The chiral Fe–CoNiP composites had a better absorbing property at 8–18 GHz than the CoNiP spirulina composite, the RL was −16.26 dB at 10.48 GHz, the absorbing band was 9.5–11.5 GHz of RL less than −10 dB, which indicated the Fe–CoNiP spirulina could be an effective absorbent used in 8–18 GHz. - Highlights: • Absorbers filled with Fe–CoNiP coating on the spirulina were fabricated. • The permittivity and permeability increased as CIPs coated. • The Fe material enhanced the electromagnetic property. • The spirulina coated Fe–CoNiP was effective in 8–18 GHz.

  18. Absorbing device for stationary arrangement in the lattice of a boiling water reactor

    International Nuclear Information System (INIS)

    Fredin, B.; Nylund, O.

    1980-01-01

    The invention refers to an absorbing device for stationary arrangement in the lattice of a BWR in a gap between two bundles of vertical fuel rods. It consists of at least one absorbing plate containing burnable absorbing material. Both lateral surfaces of this plate are directed to one surface each of the bundles mentioned above. According to the invention the absorbing material is contained in channels formed by welding together two adjacent sheet elements, at least one of which being corrugated. The welds will be made at the points where to tops of the waves touch the other sheet element. (orig.) [de

  19. Generalized pin factor methodology for LWR reload cores with discrete burnable absorbers

    International Nuclear Information System (INIS)

    Hah, C.J.; Hideki Matsumoto; Toshikazu Ida; Lee, C.; Chao, Y.A.

    2005-01-01

    Discrete burnable absorbers are used to suppress excess reactivity as well as peak pin power in an assembly. After the burn-out of absorption material, discrete burnable absorbers are usually removed from assembly guide tubes for the next cycle. For that case, the pin factors with discrete burnable absorbers cannot be used since the assembly configuration is physically changed. The pin factors without discrete burnable absorbers also have noticeable deviation from the actual case because they do not take into account the history effect due to the residence of discrete burnable absorbers for the previous cycle. In this paper, the generalized pin factor (GPF) method is developed to accurately predict pin powers by considering the history effect. The method uses a second-order polynomial function to approximate the history effect which builds up during the residence of burnable absorber material and employs a linear approximation to simulate the decay of the history effect after discrete burnable absorbers are removed. The verification results from Westinghouse Vantage- 5H assemblies with WABAs showed that pin power errors were significantly reduced by using the GPF. (authors)

  20. On the definition of absorbed dose

    International Nuclear Information System (INIS)

    Grusell, Erik

    2015-01-01

    Purpose: The quantity absorbed dose is used extensively in all areas concerning the interaction of ionizing radiation with biological organisms, as well as with matter in general. The most recent and authoritative definition of absorbed dose is given by the International Commission on Radiation Units and Measurements (ICRU) in ICRU Report 85. However, that definition is incomplete. The purpose of the present work is to give a rigorous definition of absorbed dose. Methods: Absorbed dose is defined in terms of the random variable specific energy imparted. A random variable is a mathematical function, and it cannot be defined without specifying its domain of definition which is a probability space. This is not done in report 85 by the ICRU, mentioned above. Results: In the present work a definition of a suitable probability space is given, so that a rigorous definition of absorbed dose is possible. This necessarily includes the specification of the experiment which the probability space describes. In this case this is an irradiation, which is specified by the initial particles released and by the material objects which can interact with the radiation. Some consequences are discussed. Specific energy imparted is defined for a volume, and the definition of absorbed dose as a point function involves the specific energy imparted for a small mass contained in a volume surrounding the point. A possible more precise definition of this volume is suggested and discussed. Conclusions: The importance of absorbed dose motivates a proper definition, and one is given in the present work. No rigorous definition has been presented before. - Highlights: • A stringent definition of absorbed dose is given. • This requires the definition of an irradiation and a suitable probability space. • A stringent definition is important for an understanding of the concept absorbed dose

  1. Improved rapidly-quenched hydrogen-absorbing alloys for development of improved-capacity nickel metal hydride batteries

    Science.gov (United States)

    Ise, Tadashi; Hamamatsu, Takeo; Imoto, Teruhiko; Nogami, Mitsuzo; Nakahori, Shinsuke

    The effects of annealing a rapidly-quenched hydrogen-absorbing alloy with a stoichiometric ratio of 4.76 were investigated concerning its hydrogen-absorbing properties, crystal structure and electrochemical characteristics. Annealing at 1073 K homogenized the alloy microstructure and flattened its plateau slope in the P-C isotherms. However, annealing at 1273 K segregated a second phase rich in rare earth elements, increased the hydrogen-absorbing pressure and decreased the hydrogen-absorbing capacity. As the number of charge-discharge cycles increases, the particle size distribution of the rapidly-quenched alloy became broad due to partial pulverization. However, particle size distribution of the rapidly-quenched, annealed, alloy was sharp, since the annealing homogenized the microstructure, thereby improving the cycle characteristics. A high-capacity rectangular nickel metal hydride battery using a rapidly-quenched, annealed, surface-treated alloy for the negative electrode and an active material coated with cobalt compound containing sodium for the positive electrode was developed. The capacity of the resulting battery was 30% greater than that of a conventional battery.

  2. Enhancement of phase space density by increasing trap anisotropy in a magneto-optical trap with a large number of atoms

    International Nuclear Information System (INIS)

    Vengalattore, M.; Conroy, R.S.; Prentiss, M.G.

    2004-01-01

    The phase space density of dense, cylindrical clouds of atoms in a 2D magneto-optic trap is investigated. For a large number of trapped atoms (>10 8 ), the density of a spherical cloud is limited by photon reabsorption. However, as the atom cloud is deformed to reduce the radial optical density, the temperature of the atoms decreases due to the suppression of multiple scattering leading to an increase in the phase space density. A density of 2x10 -4 has been achieved in a magneto-optic trap containing 2x10 8 atoms

  3. The influence of atomic number on the complex formation constants by visible spectrophotometric method

    International Nuclear Information System (INIS)

    Samin; Kris-Tri-Basuki; Farida-Ernawati

    1996-01-01

    The influence of atomic number on the complex formation constants and it's application by visible spectrophotometric method has been carried out. The complex compound have been made of Y, Nd, Sm and Gd with alizarin red sulfonic in the mole fraction range of 0.20 - 0.53 and pH range of 3.5 - 5. The optimum condition of complex formation was found in the mole fraction range of 0.30 - 0.53, range of pH 3.75 - 5, and the total concentration was 0.00030 M. It was found that the formation constant (β) of alizarin red S. complex by continued variation and matrix disintegration techniques were β : (7.00 ± 0.64).10 9 of complex 3 9γ,β : (4.09±0.34).10 8 of 6 0Nd, β : (7.26 ± 0.42).10 8 of 62 S m and β : (8.38 ± 0.70).10 8 of 64 G d. It can be concluded that the atomic number of Nd is bigger than Sm which is bigger than Gd. The atomic number of Y is the smallest. (39) and the complex formation constant is a biggest. The complex compound can be used for sample analysis with limit detection of Y : 2.2 .10 -5 M, Nd : 2.9 .10 -5 M, Sm : 2.6 .10 -5 M and Gd : 2.4 .10 -5 M. The sensitivity of analysis are Y>Gd>Sm>Nd. The Y 2 O 3 sample of product result from xenotime sand contains Y 2 O 3 : 98.96 ± 1.40 % and in the filtrate (product of monazite sand) contains Nd : 0.27 ± 0.002 M

  4. Regularization of absorber or doorway states in heavy-particle collisions

    International Nuclear Information System (INIS)

    Errea, L.F.; Riera, A.; Sanchez, P.

    1994-01-01

    We present a unified theoretical basis of the recently proposed regularization method of absorber or doorway states. The theory is applicable to the close-coupling solutions of time-dependent Schroedinger equations corresponding to Hamiltonians containing singular terms and with a partial continuum spectrum. The presentation and illustration are restricted to the treatment of atomic collisions. (author)

  5. Long-term effects of neutron absorber and fuel matrix corrosion on criticality

    International Nuclear Information System (INIS)

    Culbreth, W.G.; Zielinski, P.R.

    1994-01-01

    Proposed waste package designs will require the addition of neutron absorbing material to prevent the possibility of a sustained chain reaction occurring in the fuel in the event of water intrusion. Due to the low corrosion rates of the fuel matrix and the Zircaloy cladding, there is a possibility that the neutron absorbing material will corrode and leak from the waste container long before the subsequent release of fuel matrix material. An analysis of the release of fuel matrix and neutron absorber material based on a probabilistic model was conducted and the results were used to prepare input to KENO-V, an neutron criticality code. The results demonstrate that, in the presence of water, the computed values of k eff exceeded the maximum of 0.95 for an extended period of time

  6. Microwave absorbing property of a hybrid absorbent with carbonyl irons coating on the graphite

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yonggang, E-mail: xuyonggang221@163.com [Science and Technology on Electromagnetic Scattering Laboratory, Shanghai, 200438 (China); Yan, Zhenqiang; Zhang, Deyuan [Bionic and Micro/Nano/Bio Manufacturing Technology Research Center, School of Mechanical Engineering and Automation, Beihang University, Beijing 100191 (China)

    2015-11-30

    Graphical abstract: The absorbing property could be enhanced as the CIPs coated on the graphite. - Highlights: • Absorbers filled with CIPs coating on the graphite was fabricated. • The permittivity and permeability increased as CIPs coated. • The CIP materials enhanced the electromagnetic property. • The graphite coated CIPs were effective in 2–18 GHz. - Abstract: The hybrid absorbent filled with carbonyl iron particles (CIPs) coating on the graphite was prepared using a chemical vapor decomposition (CVD) process. X-ray diffraction (XRD) patterns were done to analyze the particle crystal grain structure. The complex permittivity and permeability were measured using a vector network analyzer in the frequency range of 2–18 GHz. The results showed that α-Fe appeared in the super-lattice diffraction peaks in XRD graph. The composites added CIPs coating on the graphite had a higher permittivity and imaginary permeability due to the superior microwave dielectric loss and magnetic loss of the CIPs. The reflection loss (RL) result showed that composites filled with 5 vol% Fe-graphite had an excellent absorbing property in the 2–18 GHz, the minimum RL was −25.14 dB at 6 mm and −26.52 dB at 8 mm, respectively.

  7. Thermal Shielding Effects of a Damaged Shock Absorber and an Intact Shock Absorber

    Energy Technology Data Exchange (ETDEWEB)

    Bang, K. S.; Lee, J. C.; Kim, K. Y.; Seo, C. S.; Seo, K. S. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2011-05-15

    In order to safely transport the radioactive waste arising from the hot test of an ACP(Advanced Spent Fuel Conditioning Process) a shipping package is required. Therefore, KAERI is developing a shipping package to transport the radioactive waste arising from the ACPF during a hot test. The regulatory requirements for a Type B package are specified in the Korea Most Act 2009-37, IAEA Safety Standard Series No. TS-R-1, and US 10 CFR Part. These regulatory guidelines classify the hot cell cask as a Type B package, and state that the Type B package for transporting radioactive materials should be able to withstand a test sequence consisting of a 9 m drop onto an unyielding surface, a 1 m drop onto a puncture bar, and a 30 minute fully engulfing fire. Greiner et al. investigated the thermal protection provided by shock absorbers by using the CAFE computer code. To evaluate the thermal shielding effect of the shock absorber, the thermal test was performed by using a 1/2 scale model with a shock absorber which was damaged by both a 9 m drop test and a 1 m puncture test. For the purpose of comparison, the thermal test was also carried out by using a 1/2 scale model with the intact shock absorber

  8. Experimental research on the contrast production of the chemical elements with the atomic numbers 1-83 in a computer-totalbody-tomogram

    International Nuclear Information System (INIS)

    Kirschner, H.; Burmester, U.; Stringaris, K.

    1979-01-01

    The contrast production for the chemical elements with the atomic numbers Z=1-83 were determined by computer-tomography. With the formula relation of the Δ-number and the atomic number can one compute the contrast production of any chosen chemical compound. Iodine-free and inorganic iodine-containing contrast media are examined for their contrast production and compared with presently used organic iodine-containing contrast media. The contrast enhancement of organic contrast media in tissue are discussed. (orig.) [de

  9. Radiation trapping in atomic absorption spectroscopy at lead determination in different matricies

    International Nuclear Information System (INIS)

    El-Gohary, Z.

    2005-01-01

    The determination of lead by flame atomic absorption analysis in the presence of Sn and Fe atoms and different matrices such as OH and SO 3 was investigated with the objective of understanding the spectral interference processes at the analytical lines 283.31 nm for a wide range of concentration. The radiation trapping factor was interpreted and evaluated assuming Voigt distribution of the atomic and rotational lines in the flame. The radiation trapping factor was increased by increasing the number density (plasma of the absorbing medium is optically thick). In plasma, there is a certain point of equilibrium between the trapping and the escaping of radiation, which is relevant to 50% of absorption. The spectral background interference can cause a variation of the number density at equilibrium point as a result of the degree of overlap with the analytical line. The spectral background interference can be easily avoided by using another resonance absorption line for the analysis. The chemical modification of the matrix is applied to minimize the interference effect. Nitric acid, ammonium nitrate and magnesium nitrate are most commonly recommended as matrix modifiers

  10. Determination of the number density of excited and ground Zn atoms during rf magnetron sputtering of ZnO target

    Energy Technology Data Exchange (ETDEWEB)

    Maaloul, L.; Gangwar, R. K.; Stafford, L., E-mail: luc.stafford@umontreal.ca [Département de Physique, Université de Montréal, Montréal, Québec H3C 3J7 (Canada)

    2015-07-15

    A combination of optical absorption spectroscopy (OAS) and optical emission spectroscopy measurements was used to monitor the number density of Zn atoms in excited 4s4p ({sup 3}P{sub 2} and {sup 3}P{sub 0}) metastable states as well as in ground 4s{sup 2} ({sup 1}S{sub 0}) state in a 5 mTorr Ar radio-frequency (RF) magnetron sputtering plasma used for the deposition of ZnO-based thin films. OAS measurements revealed an increase by about one order of magnitude of Zn {sup 3}P{sub 2} and {sup 3}P{sub 0} metastable atoms by varying the self-bias voltage on the ZnO target from −115 to −300 V. Over the whole range of experimental conditions investigated, the triplet-to-singlet metastable density ratio was 5 ± 1, which matches the statistical weight ratio of these states in Boltzmann equilibrium. Construction of a Boltzmann plot using all Zn I emission lines in the 200–500 nm revealed a constant excitation temperature of 0.33 ± 0.04 eV. In combination with measured populations of Zn {sup 3}P{sub 2} and {sup 3}P{sub 0} metastable atoms, this temperature was used to extrapolate the absolute number density of ground state Zn atoms. The results were found to be in excellent agreement with those obtained previously by actinometry on Zn atoms using Ar as the actinometer gas [L. Maaloul and L. Stafford, J. Vac. Sci. Technol., A 31, 061306 (2013)]. This set of data was then correlated to spectroscopic ellipsometry measurements of the deposition rate of Zn atoms on a Si substrate positioned at 12 cm away from the ZnO target. The deposition rate scaled linearly with the number density of Zn atoms. In sharp contrast with previous studies on RF magnetron sputtering of Cu targets, these findings indicate that metastable atoms play a negligible role on the plasma deposition dynamics of Zn-based coatings.

  11. Derivation of linear attenuation coefficients from CT numbers for low-energy photons

    International Nuclear Information System (INIS)

    Watanabe, Y.

    1999-01-01

    One can estimate photon attenuation properties from the CT number. In a standard method one assumes that the linear attenuation coefficient is proportional to electron density and ignores its nonlinear dependence on atomic number. When the photon energy is lower than about 50 keV, such as for brachytherapy applications, however, photoelectric absorption and Rayleigh scattering become important. Hence the atomic number must be explicitly considered in estimating the linear attenuation coefficient. In this study we propose a method to more accurately estimate the linear attenuation coefficient of low-energy photons from CT numbers. We formulate an equation that relates the CT number to the electron density and the effective atomic number. We use a CT calibration phantom to determine unknown coefficients in the equation. The equation with a given CT number is then solved for the effective atomic number, which in turn is used to calculate the linear attenuation coefficient for low-energy photons. We use the CT phantom to test the new method. The method significantly improves the standard method in estimating the attenuation coefficient at low photon energies (20keV≤E≤40keV) for materials with high atomic numbers. (author)

  12. Combining linear polarization spectroscopy and the Representative Layer Theory to measure the Beer-Lambert law absorbance of highly scattering materials.

    Science.gov (United States)

    Gobrecht, Alexia; Bendoula, Ryad; Roger, Jean-Michel; Bellon-Maurel, Véronique

    2015-01-01

    Visible and Near Infrared (Vis-NIR) Spectroscopy is a powerful non destructive analytical method used to analyze major compounds in bulk materials and products and requiring no sample preparation. It is widely used in routine analysis and also in-line in industries, in-vivo with biomedical applications or in-field for agricultural and environmental applications. However, highly scattering samples subvert Beer-Lambert law's linear relationship between spectral absorbance and the concentrations. Instead of spectral pre-processing, which is commonly used by Vis-NIR spectroscopists to mitigate the scattering effect, we put forward an optical method, based on Polarized Light Spectroscopy to improve the absorbance signal measurement on highly scattering samples. This method selects part of the signal which is less impacted by scattering. The resulted signal is combined in the Absorption/Remission function defined in Dahm's Representative Layer Theory to compute an absorbance signal fulfilling Beer-Lambert's law, i.e. being linearly related to concentration of the chemicals composing the sample. The underpinning theories have been experimentally evaluated on scattering samples in liquid form and in powdered form. The method produced more accurate spectra and the Pearson's coefficient assessing the linearity between the absorbance spectra and the concentration of the added dye improved from 0.94 to 0.99 for liquid samples and 0.84-0.97 for powdered samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Cheminoes: A Didactic Game to Learn Chemical Relationships between Valence, Atomic Number, and Symbol

    Science.gov (United States)

    Moreno, Luis F.; Hincapié, Gina; Alzate, María Victoria

    2014-01-01

    Cheminoes is a didactic game that enables the meaningful learning of some relations between concepts such as chemical element, valence, atomic number, and chemical symbol for the first 36 chemical elements of the periodic system. Among the students who have played the game, their opinions of the activity were positive, considering the game to be a…

  14. The effective atomic numbers of some biomolecules calculated by two methods: A comparative study

    DEFF Research Database (Denmark)

    Manohara, S.R.; Hanagodimath, S.M.; Gerward, Leif

    2009-01-01

    The effective atomic numbers Z(eff) of some fatty acids and amino acids have been calculated by two numerical methods, a direct method and an interpolation method, in the energy range of 1 keV-20 MeV. The notion of Z(eff) is given a new meaning by using a modern database of photon interaction cro...

  15. Quantitative neutron radiography using neutron absorbing honeycomb

    International Nuclear Information System (INIS)

    Tamaki, Masayoshi; Oda, Masahiro; Takahashi, Kenji; Ohkubo, Kohei; Tasaka, Kanji; Tsuruno, Akira; Matsubayashi, Masahito.

    1993-01-01

    This investigation concerns quantitative neutron radiography and computed tomography by using a neutron absorbing honeycomb collimator. By setting the neutron absorbing honeycomb collimator between object and imaging system, neutrons scattered in the object were absorbed by the honeycomb material and eliminated before coming to the imaging system, but the neutrons which were transmitted the object without interaction could reach the imaging system. The image by purely transmitted neutrons gives the quantitative information. Two honeycombs were prepared with coating of boron nitride and gadolinium oxide and evaluated for the quantitative application. The relation between the neutron total cross section and the attenuation coefficient confirmed that they were in a fairly good agreement. Application to quantitative computed tomography was also successfully conducted. The new neutron radiography method using the neutron-absorbing honeycomb collimator for the elimination of the scattered neutrons improved remarkably the quantitativeness of the neutron radiography and computed tomography. (author)

  16. Topics in atomic physics

    CERN Document Server

    Burkhardt, Charles E

    2006-01-01

    The study of atomic physics propelled us into the quantum age in the early twentieth century and carried us into the twenty-first century with a wealth of new and, in some cases, unexplained phenomena. Topics in Atomic Physics provides a foundation for students to begin research in modern atomic physics. It can also serve as a reference because it contains material that is not easily located in other sources. A distinguishing feature is the thorough exposition of the quantum mechanical hydrogen atom using both the traditional formulation and an alternative treatment not usually found in textbooks. The alternative treatment exploits the preeminent nature of the pure Coulomb potential and places the Lenz vector operator on an equal footing with other operators corresponding to classically conserved quantities. A number of difficult to find proofs and derivations are included as is development of operator formalism that permits facile solution of the Stark effect in hydrogen. Discussion of the classical hydrogen...

  17. Design and testing of a shock absorber for a type I container

    International Nuclear Information System (INIS)

    Sappok, M.; Beine, B.; Rittscher, D.; Jais, M.

    1994-01-01

    A simple method of designing a shock absorber to protect a type B cast-iron container is developed. The results of deformation tests of the structural material (steel pipes) used for the shock absorber are presented. The accelerations and strains measured during the 9m drop tests of the container with the shock absorber are compared with the theoretical results of the calculations for the shock absorber design. ((orig.))

  18. A study of the effective atomic number of SixPb0.7-x(Fe2O30.3 ternary alloys for photons

    Directory of Open Access Journals (Sweden)

    Buyukyildiz Mehmet

    2016-01-01

    Full Text Available The effective atomic number (Zeff of SixPb0.7-x(Fe2O30.3 ternary alloys was obtained for photons. Rayleigh to Compton scattering ratio (R/C has been determined to obtain the Zeff of SixPb0.7-x(Fe2O30.3 ternary alloys of varying Si and Pb (10 %-60 % content for scattering of 59.54 keV g-rays at an angle of 130°. The theoretical R/C ratios of elements were plotted as a function of the atomic number and fitted to a polynomial equation. Experimental R/C values of alloys were then used to obtain Zeff using this fit equation. Also, Zeff values of these alloys were determined for the first time by interpolating the R/C of the material using the R/C data of adjacent elements in between the R/C of the alloy lies. The agreement between the interpolation method and the fit equation was quite satisfactory. The obtained Zeff for photon scattering were then compared to the Zeff for total photon attenuation obtained using the Auto-Zeff program. Significant variations were observed between the Zeff for scattering and the total attenuation of gamma rays.

  19. Shock absorber in combination with a nuclear reactor core structure

    International Nuclear Information System (INIS)

    Housman, J.J.

    1976-01-01

    This invention relates to the provision of shock absorbers for use in blind control rod passages of a nuclear reactor core structure which are not subject to degradation. The shock absorber elements are made of a porous brittle carbonaceous material, a porous brittle ceramic material, or a porous brittle refractory oxide and have a void volume of between 30% and 70% of the total volume of the element for energy absorption by fracturing due to impact loading by a control rod. (UK)

  20. Effect of physical, chemical and electro-kinetic properties of pumice samples on radiation shielding properties of pumice material

    International Nuclear Information System (INIS)

    Tapan, Mücip; Yalçın, Zeynel; İçelli, Orhan; Kara, Hüsnü; Orak, Salim; Özvan, Ali; Depci, Tolga

    2014-01-01

    Highlights: • Radiation shielding properties of pumice materials are studied. • The relationship between physical, chemical and electro-kinetic properties pumice samples is identified. • The photon atomic parameters are important for the absorber peculiarity of the pumices. - Abstract: Pumice has been used in cement, concrete, brick, and ceramic industries as an additive and aggregate material. In this study, some gamma-ray photon absorption parameters such as the total mass attenuation coefficients, effective atomic number and electronic density have been investigated for six different pumice samples. Numerous values of energy related parameters from low energy (1 keV) to high energy (100 MeV) were calculated using WinXCom programme. The relationship between radiation shielding properties of the pumice samples and their physical, chemical and electro-kinetic properties was evaluated using simple regression analysis. Simple regression analysis indicated a strong correlation between photon energy absorption parameters and density and SiO 2 , Fe 2 O 3 , CaO, MgO, TiO 2 content of pumice samples in this study. It is found that photon energy absorption parameters are not related to electro-kinetic properties of pumice samples

  1. Preparation of PtRu/Carbon hybrid materials by hydrothermal carbonization: A study of the Pt:Ru atomic ratio

    International Nuclear Information System (INIS)

    Tusi, Marcelo Marques; Brandalise, Michele; Correa, Olandir Vercino; Oliveira Neto, Almir; Linardi, Marcelo; Spinace, Estevam Vitorio; Villalba, Juan Carlo

    2009-01-01

    PtRu/Carbon materials with different Pt:Ru atomic ratios (30:70, 50:50, 60:40, 80:20 and 90:10) and 5 wt% of nominal metal load were prepared by hydrothermal carbonization using H 2 PtCl 6.6 H 2 O and RuCl 3. xH 2 O as metals sources and catalysts of the carbonization process and starch as carbon source and reducing agent. The obtained materials were treated at 900 deg C under argon and characterized by EDX, XRD and cyclic voltammetry. The electro-oxidation of methanol was studied by cyclic voltammetry and chronoamperometry using thin porous coating technique. The PtRu/Carbon materials showed Pt:Ru atomic ratios obtained by EDX similar to the nominal ones. XRD analysis showed that Pt face-cubic centered (FCC) and Ru hexagonal close-packed (HCP) phases coexist in the obtained materials. The average crystallite sizes of the Pt (FCC) phase were in the range of 8-12 nm. The material prepared with Pt:Ru atomic ratio of 50:50 showed the best performance for methanol electro-oxidation. (author)

  2. Can Plant-Based Natural Flax Replace Basalt and E-Glass for Fiber-Reinforced Polymer Tubular Energy Absorbers? A Comparative Study on Quasi-Static Axial Crushing

    Directory of Open Access Journals (Sweden)

    Libo Yan

    2017-12-01

    Full Text Available Using plant-based natural fibers to substitute glass fibers as reinforcement of composite materials is of particular interest due to their economic, technical, and environmental significance. One potential application of plant-based natural fiber reinforced polymer (FRP composites is in automotive engineering as crushable energy absorbers. Current study experimentally investigated and compared the energy absorption efficiency of plant-based natural flax, mineral-based basalt, and glass FRP (GFRP composite tubular energy absorbers subjected to quasi-static axial crushing. The effects of number of flax fabric layer, the use of foam filler and the type of fiber materials on the crashworthiness characteristics, and energy absorption capacities were discussed. In addition, the failure mechanisms of the hollow and foam-filled flax, basalt, and GFRP tubes in quasi-static axial crushing were analyzed and compared. The test results showed that the energy absorption capabilities of both hollow and foam-filled energy absorbers made of flax were superior to the corresponding energy absorbers made of basalt and were close to energy absorbers made of glass. This study, therefore, indicated that flax fiber has the great potential to be suitable replacement of basalt and glass fibers for crushable energy absorber application.

  3. Synthesis and microwave absorbing characteristics of functionally graded carbonyl iron/polyurethane composites

    Directory of Open Access Journals (Sweden)

    R. B. Yang

    2016-05-01

    Full Text Available Radar absorbing materials (RAMs also known as microwave absorbers, which can absorb and dissipate incident electromagnetic wave, are widely used in the fields of radar-cross section reduction, electromagnetic interference (EMI reduction and human health protection. In this study, the synthesis of functionally graded material (FGM (CI/Polyurethane composites, which is fabricated with semi-sequentially varied composition along the thickness, is implemented with a genetic algorithm (GA to optimize the microwave absorption efficiency and bandwidth of FGM. For impedance matching and broad-band design, the original 8-layered FGM was obtained by the GA method to calculate the thickness of each layer for a sequential stacking of FGM from 20, 30, 40, 50, 60, 65, 70 and 75 wt% of CI fillers. The reflection loss of the original 8-layered FGM below –10 dB can be obtained in the frequency range of 5.12∼18 GHz with a total thickness of 9.66 mm. Further optimization reduces the number of the layers and the stacking sequence of the optimized 4-layered FGM is 20, 30, 65, 75 wt% with thickness of 0.8, 1.6, 0.6 and 1.0 mm, respectively. The synthesis and measurement of the optimized 4-layered FGM with a thickness of 4 mm reveal a minimum reflection loss of –25.2 dB at 6.64 GHz and its bandwidth below – 10 dB is larger than 12.8 GHz.

  4. New atom probe approaches to studying segregation in nanocrystalline materials

    International Nuclear Information System (INIS)

    Samudrala, S.K.; Felfer, P.J.; Araullo-Peters, V.J.; Cao, Y.; Liao, X.Z.; Cairney, J.M.

    2013-01-01

    Atom probe is a technique that is highly suited to the study of nanocrystalline materials. It can provide accurate atomic-scale information about the composition of grain boundaries in three dimensions. In this paper we have analysed the microstructure of a nanocrystalline super-duplex stainless steel prepared by high pressure torsion (HPT). Not all of the grain boundaries in this alloy display obvious segregation, making visualisation of the microstructure challenging. In addition, the grain boundaries present in the atom probe data acquired from this alloy have complex shapes that are curved at the scale of the dataset and the interfacial excess varies considerably over the boundaries, making the accurate characterisation of the distribution of solute challenging using existing analysis techniques. In this paper we present two new data treatment methods that allow the visualisation of boundaries with little or no segregation, the delineation of boundaries for further analysis and the quantitative analysis of Gibbsian interfacial excess at boundaries, including the capability of excess mapping. - Highlights: ► New data treatment methods allow delineation of grain boundaries, even without segregation. ► Proxigrams calculated from the surfaces accurately show the extent of segregation. ► Tessellation of the data volume can be used to map the Gibbsian interfacial excess

  5. New atom probe approaches to studying segregation in nanocrystalline materials

    Energy Technology Data Exchange (ETDEWEB)

    Samudrala, S.K.; Felfer, P.J.; Araullo-Peters, V.J. [School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney, NSW 2006 (Australia); The Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006 (Australia); Cao, Y.; Liao, X.Z. [School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney, NSW 2006 (Australia); Cairney, J.M., E-mail: julie.cairney@sydney.edu.au [School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney, NSW 2006 (Australia); The Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006 (Australia)

    2013-09-15

    Atom probe is a technique that is highly suited to the study of nanocrystalline materials. It can provide accurate atomic-scale information about the composition of grain boundaries in three dimensions. In this paper we have analysed the microstructure of a nanocrystalline super-duplex stainless steel prepared by high pressure torsion (HPT). Not all of the grain boundaries in this alloy display obvious segregation, making visualisation of the microstructure challenging. In addition, the grain boundaries present in the atom probe data acquired from this alloy have complex shapes that are curved at the scale of the dataset and the interfacial excess varies considerably over the boundaries, making the accurate characterisation of the distribution of solute challenging using existing analysis techniques. In this paper we present two new data treatment methods that allow the visualisation of boundaries with little or no segregation, the delineation of boundaries for further analysis and the quantitative analysis of Gibbsian interfacial excess at boundaries, including the capability of excess mapping. - Highlights: ► New data treatment methods allow delineation of grain boundaries, even without segregation. ► Proxigrams calculated from the surfaces accurately show the extent of segregation. ► Tessellation of the data volume can be used to map the Gibbsian interfacial excess.

  6. Absorber rod driving into a gas-cooled nuclear reactor

    International Nuclear Information System (INIS)

    Elter, C.; Schmitt, H.; Schoening, J.

    1987-01-01

    The absorber rod consists of a hollow cylinder which has a layer of absorber material applied on its inside circumferential surface. The absorber rod is held via a guide sleeve, which is supported centrally in a hole in the side reflector. The guidance within the sleeve is provided by flanges on the hollow cylinder. The movement of the hollow cylinder is carried out hydraulically or pneumatically. A flow of cooling gas is used for cooling, which is passed through the inner central areas of the hollow cylinder and the guide sleeve. (DG) [de

  7. Atomic scale insight into the amorphous structure of Cu doped GeTe phase-change material

    International Nuclear Information System (INIS)

    Zhang, Linchuan; Sa, Baisheng; Zhou, Jian; Sun, Zhimei; Song, Zhitang

    2014-01-01

    GeTe shows promising application as a recording material for phase-change nonvolatile memory due to its fast crystallization speed and extraordinary amorphous stability. To further improve the performance of GeTe, various transition metals, such as copper, have been doped in GeTe in recent works. However, the effect of the doped transition metals on the stability of amorphous GeTe is not known. Here, we shed light on this problem for the system of Cu doped GeTe by means of ab initio molecular dynamics calculations. Our results show that the doped Cu atoms tend to agglomerate in amorphous GeTe. Further, base on analyzing the pair correlation functions, coordination numbers and bond angle distributions, remarkable changes in the local structure of amorphous GeTe induced by Cu are obviously seen. The present work may provide some clues for understanding the effect of early transition metals on the local structure of amorphous phase-change compounds, and hence should be helpful for optimizing the structure and performance of phase-change materials by doping transition metals.

  8. Distortion of Local Atomic Structures in Amorphous Ge-Sb-Te Phase Change Materials

    Science.gov (United States)

    Hirata, A.; Ichitsubo, T.; Guan, P. F.; Fujita, T.; Chen, M. W.

    2018-05-01

    The local atomic structures of amorphous Ge-Sb-Te phase-change materials have yet to be clarified and the rapid crystal-amorphous phase change resulting in distinct optical contrast is not well understood. We report the direct observation of local atomic structures in amorphous Ge2Sb2Te5 using "local" reverse Monte Carlo modeling dedicated to an angstrom-beam electron diffraction analysis. The results corroborated the existence of local structures with rocksalt crystal-like topology that were greatly distorted compared to the crystal symmetry. This distortion resulted in the breaking of ideal octahedral atomic environments, thereby forming local disordered structures that basically satisfied the overall amorphous structure factor. The crystal-like distorted octahedral structures could be the main building blocks in the formation of the overall amorphous structure of Ge-Sb-Te.

  9. Radiation shielding and effective atomic number studies in different types of shielding concretes, lead base and non-lead base glass systems for total electron interaction: A comparative study

    International Nuclear Information System (INIS)

    Kurudirek, Murat

    2014-01-01

    Highlights: • Radiation shielding calculations for concretes and glass systems. • Assigning effective atomic number for the given materials for total electron interaction. • Glass systems generally have better shielding ability than concretes. - Abstract: Concrete has been widely used as a radiation shielding material due to its extremely low cost. On the other hand, glass systems, which make everything inside visible to observers, are considered as promising shielding materials as well. In the present work, the effective atomic numbers, Z eff of some concretes and glass systems (industrial waste containing glass, Pb base glass and non-Pb base glass) have been calculated for total electron interaction in the energy region of 10 keV–1 GeV. Also, the continuous slowing down approximation (CSDA) ranges for the given materials have been calculated in the wide energy region to show the shielding effectiveness of the given materials. The glass systems are not only compared to different types of concretes but also compared to the lead base glass systems in terms of shielding. Moreover, the obtained results for total electron interaction have been compared to the results for total photon interaction wherever possible. In general, it has been observed that the glass systems have superior properties than most of the concretes over the high-energy region with respect to the electron interaction. Also, glass systems without lead show better electron stopping than lead base glasses at some energy regions as well. Along with the photon attenuation capability, it is seen that Fly Ash base glass systems have not only greater electron stopping capability but also have greater photon attenuation especially in high energy region when compared with standard shielding concretes

  10. Radiation shielding and effective atomic number studies in different types of shielding concretes, lead base and non-lead base glass systems for total electron interaction: A comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Kurudirek, Murat, E-mail: mkurudirek@gmail.com

    2014-12-15

    Highlights: • Radiation shielding calculations for concretes and glass systems. • Assigning effective atomic number for the given materials for total electron interaction. • Glass systems generally have better shielding ability than concretes. - Abstract: Concrete has been widely used as a radiation shielding material due to its extremely low cost. On the other hand, glass systems, which make everything inside visible to observers, are considered as promising shielding materials as well. In the present work, the effective atomic numbers, Z{sub eff} of some concretes and glass systems (industrial waste containing glass, Pb base glass and non-Pb base glass) have been calculated for total electron interaction in the energy region of 10 keV–1 GeV. Also, the continuous slowing down approximation (CSDA) ranges for the given materials have been calculated in the wide energy region to show the shielding effectiveness of the given materials. The glass systems are not only compared to different types of concretes but also compared to the lead base glass systems in terms of shielding. Moreover, the obtained results for total electron interaction have been compared to the results for total photon interaction wherever possible. In general, it has been observed that the glass systems have superior properties than most of the concretes over the high-energy region with respect to the electron interaction. Also, glass systems without lead show better electron stopping than lead base glasses at some energy regions as well. Along with the photon attenuation capability, it is seen that Fly Ash base glass systems have not only greater electron stopping capability but also have greater photon attenuation especially in high energy region when compared with standard shielding concretes.

  11. Quantum-mechanical transport equation for atomic systems.

    Science.gov (United States)

    Berman, P. R.

    1972-01-01

    A quantum-mechanical transport equation (QMTE) is derived which should be applicable to a wide range of problems involving the interaction of radiation with atoms or molecules which are also subject to collisions with perturber atoms. The equation follows the time evolution of the macroscopic atomic density matrix elements of atoms located at classical position R and moving with classical velocity v. It is quantum mechanical in the sense that all collision kernels or rates which appear have been obtained from a quantum-mechanical theory and, as such, properly take into account the energy-level variations and velocity changes of the active (emitting or absorbing) atom produced in collisions with perturber atoms. The present formulation is better suited to problems involving high-intensity external fields, such as those encountered in laser physics.

  12. RackSaver neutron absorbing device development and testing

    International Nuclear Information System (INIS)

    Lambert, R.; O'Leary, P.; Roberts, P.

    1996-01-01

    Siemens Power Corporation (SPC), in cooperation with the Electric Power Research Institute (EPRI), has developed the RackSaver neutron absorbing insert. The RackSaver insert can be installed onto spent nuclear fuel assemblies to replace deteriorating Boraflex neutron absorbing material installed in some spent-fuel storage racks. This paper describes results of a development and in-pool demonstration program performed to support potential utilization of the RackSaver neutron absorbing insert by affected utilities. The program objective was to advance the RackSaver concept into a field-demonstrated product. This objective was accomplished through three phases: design, licensing and criticality evaluations, and demonstration testing

  13. MatMCNP: A Code for Producing Material Cards for MCNP

    Energy Technology Data Exchange (ETDEWEB)

    DePriest, Kendall Russell [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Saavedra, Karen C. [American Structurepoint, Inc., Indianapolis, IN (United States)

    2014-09-01

    A code for generating MCNP material cards (MatMCNP) has been written and verified for naturally occurring, stable isotopes. The program allows for material specification as either atomic or weight percent (fractions). MatMCNP also permits the specification of enriched lithium, boron, and/or uranium. In addition to producing the material cards for MCNP, the code calculates the atomic (or number) density in atoms/barn-cm as well as the multiplier that should be used to convert neutron and gamma fluences into dose in the material specified.

  14. Fabricating method of hydrogen absorbing alloy for alkali storage battery; Arukari chikudenchiyo suiso kyuzo gokin no seizo hoho

    Energy Technology Data Exchange (ETDEWEB)

    Tadokoro, M.

    1996-03-08

    There are many grain boundaries in spherical hydrogen absorbing alloy particles prepared by rapid solidification methods such as centrifugal spraying method and gas atomizing method, and heterogeneous strains are produced at boundaries. When hydrogen absorbing alloy with large heterogeneous strain is used for preparing electrodes, many cracks are produced in hydrogen absorbing alloy to cause pulverization in the charge and discharge cycles. This invention relates to heat treatment of hydrogen absorbing alloys having spherical shape, cannon ball shape, and egg-like shape prepared by rapid solidification method in moving conditions. By this heat treatment, mutual sintering of hydrogen absorbing alloy particles can be prevented. The methods for moving hydrogen absorbing alloy are vibration or rotation of the heat treatment container in which hydrogen absorbing alloy is held and agitation of hydrogen absorbing alloy powder. Furthermore, mutual sintering of hydrogen absorbing alloy is restricted to reduce homogeneous strain by heat treatment in the range from 700{degree}C to 1,100{degree}C. 3 figs., 6 tabs.

  15. Optical properties of an atomic ensemble coupled to a band edge of a photonic crystal waveguide

    Science.gov (United States)

    Munro, Ewan; Kwek, Leong Chuan; Chang, Darrick E.

    2017-08-01

    We study the optical properties of an ensemble of two-level atoms coupled to a 1D photonic crystal waveguide (PCW), which mediates long-range coherent dipole-dipole interactions between the atoms. We show that the long-range interactions can dramatically alter the linear and nonlinear optical behavior, as compared to a typical atomic ensemble. In particular, in the linear regime, we find that the transmission spectrum contains multiple transmission dips, whose properties we characterize. Moreover, we show how the linear spectrum may be used to infer the number of atoms present in the system, constituting an important experimental tool in a regime where techniques for conventional ensembles break down. We also show that some of the transmission dips are associated with an effective ‘two-level’ resonance that forms due to the long-range interactions. In particular, under strong global driving and appropriate conditions, we find that the atomic ensemble is only capable of absorbing and emitting single collective excitations at a time. Our results are of direct relevance to atom-PCW experiments that should soon be realizable.

  16. X-ray transition yields of low-Z kaonic atoms produced in Kapton

    Energy Technology Data Exchange (ETDEWEB)

    Bazzi, M. [INFN, Laboratori Nazionali di Frascati, C.P. 13, Via E. Fermi 40, I-00044 Frascati (Roma) (Italy); Beer, G. [Department of Physics and Astronomy, University of Victoria, P.O. Box 1700 STN CNC, Victoria, BC V8W 2Y2 (Canada); Berucci, C. [INFN, Laboratori Nazionali di Frascati, C.P. 13, Via E. Fermi 40, I-00044 Frascati (Roma) (Italy); Stefan-Meyer-Institut für subatomare Physik, Boltzmanngasse 3, 1090 Wien (Austria); Bombelli, L. [Politecnico di Milano, Dipartimento di Elettronica e Informazione, Piazza L. da Vinci 32, I-20133 Milano (Italy); Bragadireanu, A.M. [INFN, Laboratori Nazionali di Frascati, C.P. 13, Via E. Fermi 40, I-00044 Frascati (Roma) (Italy); IFIN-HH, Institutul National pentru Fizica si Inginerie Nucleara Horia Hulubei, Reactorului 30, Magurele (Romania); Cargnelli, M. [Stefan-Meyer-Institut für subatomare Physik, Boltzmanngasse 3, 1090 Wien (Austria); Curceanu, C.; D' Uffizi, A. [INFN, Laboratori Nazionali di Frascati, C.P. 13, Via E. Fermi 40, I-00044 Frascati (Roma) (Italy); Fiorini, C. [Politecnico di Milano, Dipartimento di Elettronica e Informazione, Piazza L. da Vinci 32, I-20133 Milano (Italy); Ghio, F. [INFN Sezione di Roma I and Instituto Superiore di Sanita, I-00161 Roma (Italy); Guaraldo, C. [INFN, Laboratori Nazionali di Frascati, C.P. 13, Via E. Fermi 40, I-00044 Frascati (Roma) (Italy); Hayano, R.S. [University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo (Japan); Iliescu, M. [INFN, Laboratori Nazionali di Frascati, C.P. 13, Via E. Fermi 40, I-00044 Frascati (Roma) (Italy); Ishiwatari, T., E-mail: tomoichi.ishiwatari@assoc.oeaw.ac.at [Stefan-Meyer-Institut für subatomare Physik, Boltzmanngasse 3, 1090 Wien (Austria); Iwasaki, M. [RIKEN, Institute of Physical and Chemical Research, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); and others

    2013-10-23

    The X-ray transition yields of kaonic atoms produced in Kapton polyimide (C{sub 22}H{sub 10}N{sub 2}O{sub 5}) were measured for the first time in the SIDDHARTA experiment. X-ray yields of the kaonic atoms with low atomic numbers (Z=6,7, and 8) and transitions with high principal quantum numbers (n=5–8) were determined. The relative yields of the successive transitions in the same atoms and the yield ratios of carbon-to-nitrogen (C:N) and carbon-to-oxygen (C:O) for the same transitions were also determined. These X-ray yields provide important information for understanding the capture ratios and cascade mechanisms of kaonic atoms produced in a compound material, such as Kapton.

  17. Influence of the electromagnetic parameters on the surface wave attenuation in thin absorbing layers

    Science.gov (United States)

    Li, Yinrui; Li, Dongmeng; Wang, Xian; Nie, Yan; Gong, Rongzhou

    2018-05-01

    This paper describes the relationships between the surface wave attenuation properties and the electromagnetic parameters of radar absorbing materials (RAMs). In order to conveniently obtain the attenuation constant of TM surface waves over a wide frequency range, the simplified dispersion equations in thin absorbing materials were firstly deduced. The validity of the proposed method was proved by comparing with the classical dispersion equations. Subsequently, the attenuation constants were calculated separately for the absorbing layers with hypothetical relative permittivity and permeability. It is found that the surface wave attenuation properties can be strongly tuned by the permeability of RAM. Meanwhile, the permittivity should be appropriate so as to maintain high cutoff frequency. The present work provides specific methods and designs to improve the attenuation performances of radar absorbing materials.

  18. Atomic force microscopy for two-dimensional materials: A tutorial review

    Science.gov (United States)

    Zhang, Hang; Huang, Junxiang; Wang, Yongwei; Liu, Rui; Huai, Xiulan; Jiang, Jingjing; Anfuso, Chantelle

    2018-01-01

    Low dimensional materials exhibit distinct properties compared to their bulk counterparts. A plethora of examples have been demonstrated in two-dimensional (2-D) materials, including graphene and transition metal dichalcogenides (TMDCs). These novel and intriguing properties at the nano-, molecular- and even monatomic scales have triggered tremendous interest and research, from fundamental studies to practical applications and even device fabrication. The unique behaviors of 2-D materials result from the special structure-property relationships that exist between surface topographical variations and mechanical responses, electronic structures, optical characteristics, and electrochemical properties. These relationships are generally convoluted and sensitive to ambient and external perturbations. Characterizing these systems thus requires techniques capable of providing multidimensional information under controlled environments, such as atomic force microscopy (AFM). Today, AFM plays a key role in exploring the basic principles underlying the functionality of 2-D materials. In this tutorial review, we provide a brief introduction to some of the unique properties of 2-D materials, followed by a summary of the basic principles of AFM and the various AFM modes most appropriate for studying these systems. Following that, we will focus on five important properties of 2-D materials and their characterization in more detail, including recent literature examples. These properties include nanomechanics, nanoelectromechanics, nanoelectrics, nanospectroscopy, and nanoelectrochemistry.

  19. Atomic processes in matter-antimatter interactions

    International Nuclear Information System (INIS)

    Morgan, D.L.

    1988-01-01

    Atomic processes dominate antiproton stopping in matter at nearly all energies of interest. They significantly influence or determine the antiproton annihilation rate at all energies around or below several MeV. This article reviews what is known about these atomic processes. For stopping above about 10 eV the processes are antiproton-electron collisions, effective at medium keV through high MeV energies, and elastic collisions with atoms and adiabatic ionization of atoms, effective from medium eV through low keB energies. For annihilation above about 10 eV is the enhancement of the antiproton annihilation rate due to the antiproton-nucleus coulomb attraction, effective around and below a few tens of MeV. At about 10 eV and below, the atomic rearrangement/annihilation process determines both the stopping and annihilation rates. Although a fair amount of theoretical and some experimental work relevant to these processes exist, there are a number of energy ranges and material types for which experimental data does not exist and for which the theoretical information is not as well grounded or as accurate as desired. Additional experimental and theoretical work is required for accurate prediction of antiproton stopping and annihilation for energies and material relevant to antiproton experimentation and application

  20. Material discrimination using scattering and stopping of cosmic ray muons and electrons: Differentiating heavier from lighter metals as well as low-atomic weight materials

    Energy Technology Data Exchange (ETDEWEB)

    Blanpied, Gary; Kumar, Sankaran; Dorroh, Dustin; Morgan, Craig; Blanpied, Isabelle; Sossong, Michael; McKenney, Shawn; Nelson, Beth

    2015-06-01

    Reported is a new method to apply cosmic-ray tomography in a manner that can detect and characterize not only dense assemblages of heavy nuclei (like Special Nuclear Materials, SNM) but also assemblages of medium- and light-atomic-mass materials (such as metal parts, conventional explosives, and organic materials). Characterization may enable discrimination between permitted contents in commerce and contraband (explosives, illegal drugs, and the like). Our Multi-Mode Passive Detection System (MMPDS) relies primarily on the muon component of cosmic rays to interrogate Volumes of Interest (VOI). Muons, highly energetic and massive, pass essentially un-scattered through materials of light atomic mass and are only weakly scattered by conventional metals used in industry. Substantial scattering and absorption only occur when muons encounter sufficient thicknesses of heavy elements characteristic of lead and SNM. Electrons are appreciably scattered by light elements and stopped by sufficient thicknesses of materials containing medium-atomic-mass elements (mostly metals). Data include simulations based upon GEANT and measurements in the HMT (Half Muon Tracker) detector in Poway, CA and a package scanner in both Poway and Socorro NM. A key aspect of the present work is development of a useful parameter, designated the “stopping power” of a sample. The low-density regime, comprising organic materials up to aluminum, is characterized using very little scattering but a strong variation in stopping power. The medium-to-high density regime shows a larger variation in scattering than in stopping power. The detection of emitted gamma rays is another useful signature of some materials.

  1. Material discrimination using scattering and stopping of cosmic ray muons and electrons: Differentiating heavier from lighter metals as well as low-atomic weight materials

    Science.gov (United States)

    Blanpied, Gary; Kumar, Sankaran; Dorroh, Dustin; Morgan, Craig; Blanpied, Isabelle; Sossong, Michael; McKenney, Shawn; Nelson, Beth

    2015-06-01

    Reported is a new method to apply cosmic-ray tomography in a manner that can detect and characterize not only dense assemblages of heavy nuclei (like Special Nuclear Materials, SNM) but also assemblages of medium- and light-atomic-mass materials (such as metal parts, conventional explosives, and organic materials). Characterization may enable discrimination between permitted contents in commerce and contraband (explosives, illegal drugs, and the like). Our Multi-Mode Passive Detection System (MMPDS) relies primarily on the muon component of cosmic rays to interrogate Volumes of Interest (VOI). Muons, highly energetic and massive, pass essentially un-scattered through materials of light atomic mass and are only weakly scattered by conventional metals used in industry. Substantial scattering and absorption only occur when muons encounter sufficient thicknesses of heavy elements characteristic of lead and SNM. Electrons are appreciably scattered by light elements and stopped by sufficient thicknesses of materials containing medium-atomic-mass elements (mostly metals). Data include simulations based upon GEANT and measurements in the HMT (Half Muon Tracker) detector in Poway, CA and a package scanner in both Poway and Socorro NM. A key aspect of the present work is development of a useful parameter, designated the "stopping power" of a sample. The low-density regime, comprising organic materials up to aluminum, is characterized using very little scattering but a strong variation in stopping power. The medium-to-high density regime shows a larger variation in scattering than in stopping power. The detection of emitted gamma rays is another useful signature of some materials.

  2. Selenium determination in biological material by atomic absorption spectrophotometry in graphite furnace and using vapor generation

    International Nuclear Information System (INIS)

    Carvalho Vidal, M. de F. de.

    1984-01-01

    The applicability of the atomic absorption spectrophotometry to the determination of selenium in biological material using vapor generation and electrothermal atomization in the graphite furnace was investigated. Instrumental parameters and the analytical conditions of the methods were studied. Decomposition methods for the samples were tested, and the combustion in the Wickbold apparatus was chosen. (author) [pt

  3. Report on investigations and studies on development of materials for hydrogen absorbing alloys; Suiso kyuzo gokin no zairyo no kaihatsu ni kansuru chosa kenkyu hokokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1984-03-01

    This paper describes investigations and studies on hydrogen absorbing alloy materials and the technologies to utilize them. In the investigations and studies, literatures were collected and put into order, questionnaire surveys were performed and analyzed, lecture meetings and panel discussions were held, and the discussion results were summarized. In the present status of developing hydrogen absorbing alloys, the current status of and problems in developing such hydrogen absorbing alloys as Ti-based, Mg-based, and rare earth-based alloys were put into order. Discussions were given on prospects of possibilities of developing new alloys, making them amorphous, and putting them into mass production. In the current status of developing the utilizing technologies, such technologies as hydrogen storage systems and heat pumps were put into order and discussed. With regard to problems in hydrogen absorbing alloys, discussions were given on alloy weight, pulverization, activation, heat conductivity, and alloy costs. In discussing the safety, discussions were given on the safety and compliance with related laws and regulations relative to hydrogen transportation using a great amount of hydrogen absorbing alloys, their storage, and heat storage systems. In addition, questionnaire surveys were carried out with an objective to identify the status of developing hydrogen absorbing alloys and needs from the industries. (NEDO)

  4. Atomic and plasma-material interaction data for fusion. Vol. 13

    International Nuclear Information System (INIS)

    Clark, R.E.H.

    2007-01-01

    of the A+M Subcommittee of the International Fusion Research Council in May 2000 to initiate a Coordinated Research Project (CRP) to address data needs in this area. The Atomic and Molecular Data of the International Atomic Energy Agency initiated the CRP on 'Atomic and Molecular Data for Fusion Plasma Diagnostics' in 2001. Results from this CRP will be incorporated into the A+M Data Unit databases and will be available through the worldwide-web for global access by researchers. These data will be of interest not only for direct fusion applications, but in other research plasma studies used in accelerators, environmental research and other fields. The work of the CRP was completed in 2005. During the course of the Coordinated Research Project, new data were generated for a variety of processes impacting on a number of diagnostic procedures for fusion plasmas: spectral observations near the strike zone and divertor (where alpha particles interact with molecules) require a variety of cross-section data that have been measured and calculated during the current work programme; helium beam diagnostics from fast to thermal require cross-section data for both electron and proton impact, that have been generated during the current work programme; data have been produced for use in the determination of species from light elements such as helium, boron and hydrocarbons, as well as heavy elements such as tungsten; large amounts of data on spectral properties were generated to assist in the spectral analysis of plasma emissions; X-ray emissions from impact on surfaces have been studied and quantified; data have been generated for use in hydrogen charge exchange spectroscopy for the determination of the flow and temperature of impurities in the divertor region. The CRP on 'Atomic and molecular data for plasma diagnosis' has been very successful in meeting all of the objectives established at the beginning of the project. The present volume of Atomic and Plasma-Material

  5. Composite material reinforced with atomized quasicrystalline particles and method of making same

    Science.gov (United States)

    Biner, S.B.; Sordelet, D.J.; Lograsso, B.K.; Anderson, I.E.

    1998-12-22

    A composite material comprises an aluminum or aluminum alloy matrix having generally spherical, atomized quasicrystalline aluminum-transition metal alloy reinforcement particles disposed in the matrix to improve mechanical properties. A composite article can be made by consolidating generally spherical, atomized quasicrystalline aluminum-transition metal alloy particles and aluminum or aluminum alloy particles to form a body that is cold and/or hot reduced to form composite products, such as composite plate or sheet, with interfacial bonding between the quasicrystalline particles and the aluminum or aluminum alloy matrix without damage (e.g. cracking or shape change) of the reinforcement particles. The cold and/or hot worked composite exhibits substantially improved yield strength, tensile strength, Young`s modulus (stiffness). 3 figs.

  6. Studies on effective atomic number, electron density and kerma for some fatty acids and carbohydrates

    DEFF Research Database (Denmark)

    Manohara, S.R.; Hanagodimath, S.M.; Gerward, Leif

    2008-01-01

    The effective atomic number, Z(eff), the effective electron density, N-el, and kerma have been calculated for some fatty acids and carbohydrates for photon interaction in the extended energy range from 1 keV to 100 GeV using an accurate database of photon-interaction cross sections and the WinXCo...

  7. Microwave heating processes involving carbon materials

    Energy Technology Data Exchange (ETDEWEB)

    Menendez, J.A.; Arenillas, A.; Fidalgo, B.; Fernandez, Y.; Zubizarreta, L.; Calvo, E.G.; Bermudez, J.M. [Instituto Nacional del Carbon, CSIC, Apartado 73, 33080 Oviedo (Spain)

    2010-01-15

    Carbon materials are, in general, very good absorbents of microwaves, i.e., they are easily heated by microwave radiation. This characteristic allows them to be transformed by microwave heating, giving rise to new carbons with tailored properties, to be used as microwave receptors, in order to heat other materials indirectly, or to act as a catalyst and microwave receptor in different heterogeneous reactions. In recent years, the number of processes that combine the use of carbons and microwave heating instead of other methods based on conventional heating has increased. In this paper some of the microwave-assisted processes in which carbon materials are produced, transformed or used in thermal treatments (generally, as microwave absorbers and catalysts) are reviewed and the main achievements of this technique are compared with those obtained by means of conventional (non microwave-assisted) methods in similar conditions. (author)

  8. Mass attenuation coefficient (μ/ρ), effective atomic number (Zeff) and measurement of x-ray energy spectra using based calcium phosphate biomaterials: a comparative study

    International Nuclear Information System (INIS)

    Fernandes Z, M. A.; Da Silva, T. A.; Nogueira, M. S.; Goncalves Z, E.

    2015-10-01

    In dentistry, alveolar bone regeneration procedures using based calcium phosphate biomaterials have been shown effective. However,there are not reports in the literature of studies the interaction of low energy radiation in these biomaterials used as attenuator and not being then allowed a comparison between the theoretical values and experimental.The objective of this study was to determine the interaction of radiation parameters of four dental biomaterials - BioOss, Cerasorb M Dental, Straumann Boneceramic and Osteogen for diagnostic radiology qualities. As a material and methods, the composition of the biomaterials was determined by the analytical techniques. The samples with 0.181 cm to 0,297 cm thickness were experimentally used as attenuators for the measurement of the transmitted X-rays spectra in X-ray equipment with 50 to 90 kV range by spectrometric system comprising the Cd Te detector. After this procedure, the mass attenuation coefficient, the effective atomic number were determined and compared between all the specimens analyzed, using the program WinXCOM in the range of 10 to 200 keV. In all strains examined observed that the energy spectrum of x-rays transmitted through the BioOss has the mean energy slightly smaller than the others biomaterials for close thickness. The μ/ρ and Z eff of the biomaterials showed its dependence on photon energy and atomic number of the elements of the material analyzed. It is concluded according to the methodology employed in this study that the measurements of x-ray spectrum, μ/ρ and Z eff using biomaterials as attenuators confirmed that the thickness, density, composition of the samples, the incident photon energy are factors that determine the characteristics of radiation in a tissue or equivalent material. (Author)

  9. Methods for Computing Accurate Atomic Spin Moments for Collinear and Noncollinear Magnetism in Periodic and Nonperiodic Materials.

    Science.gov (United States)

    Manz, Thomas A; Sholl, David S

    2011-12-13

    The partitioning of electron spin density among atoms in a material gives atomic spin moments (ASMs), which are important for understanding magnetic properties. We compare ASMs computed using different population analysis methods and introduce a method for computing density derived electrostatic and chemical (DDEC) ASMs. Bader and DDEC ASMs can be computed for periodic and nonperiodic materials with either collinear or noncollinear magnetism, while natural population analysis (NPA) ASMs can be computed for nonperiodic materials with collinear magnetism. Our results show Bader, DDEC, and (where applicable) NPA methods give similar ASMs, but different net atomic charges. Because they are optimized to reproduce both the magnetic field and the chemical states of atoms in a material, DDEC ASMs are especially suitable for constructing interaction potentials for atomistic simulations. We describe the computation of accurate ASMs for (a) a variety of systems using collinear and noncollinear spin DFT, (b) highly correlated materials (e.g., magnetite) using DFT+U, and (c) various spin states of ozone using coupled cluster expansions. The computed ASMs are in good agreement with available experimental results for a variety of periodic and nonperiodic materials. Examples considered include the antiferromagnetic metal organic framework Cu3(BTC)2, several ozone spin states, mono- and binuclear transition metal complexes, ferri- and ferro-magnetic solids (e.g., Fe3O4, Fe3Si), and simple molecular systems. We briefly discuss the theory of exchange-correlation functionals for studying noncollinear magnetism. A method for finding the ground state of systems with highly noncollinear magnetism is introduced. We use these methods to study the spin-orbit coupling potential energy surface of the single molecule magnet Fe4C40H52N4O12, which has highly noncollinear magnetism, and find that it contains unusual features that give a new interpretation to experimental data.

  10. Liquid carbon dioxide absorbents, methods of using the same, and related system

    Science.gov (United States)

    Perry, Robert James; Soloveichik, Grigorii Lev; Rubinsztajn, Malgorzata Iwona; O'Brien, Michael Joseph; Lewis, Larry Neil; Lam, Tunchiao Hubert; Kniajanski, Sergei; Hancu, Dan

    2018-05-01

    A carbon dioxide absorbent composition is described, including (i) a liquid, nonaqueous silicon-based material, functionalized with one or more groups that either reversibly react with CO2 or have a high-affinity for CO2, and (ii) a hydroxy-containing solvent that is capable of dissolving both the silicon-based material and a reaction product of the silicon-based material and CO2. The absorbent may be utilized in methods to reduce carbon dioxide in an exhaust gas, and finds particular utility in power plants.

  11. Energy Analysis of Solar Collector With perforated Absorber Plate

    Directory of Open Access Journals (Sweden)

    Ammar A. Farhan

    2017-09-01

    Full Text Available The thermal performance of three solar collectors with 3, 6 mm and without perforation absorber plate was assessed experimentally. The experimental tests were implemented in Baghdad during the January and February 2017. Five values of airflow rates range between 0.01 – 0.1 m3/s were used through the test with a constant airflow rate during the test day. The variation of the following parameters air temperature difference, useful energy, absorber plate temperature, and collector efficiency was recorded every 15 minutes. The experimental data reports that the increases the number of absorber plate perforations with a small diameter is more efficient rather than increasing the hole diameter of the absorber plate with decreasing the perforation numbers. Maximum air temperature difference throughout the solar collector with 3, 6 mm perforations and without perforations are 17, 15, and 12 oC, respectively. Also, it can be concluded that the energy gained from the solar collector with 3 mm perforation absorber plate is 28.2 % more than the energy gained from solar collector without holes per day for 0.1 m3/s airflow rate. The maximum values of the thermal performance curves are 0.67, 0.64, and 0.56 for the solar collector with 3, 6 mm, and without perforations, respectively.

  12. Role of the calcaneal heel pad and polymeric shock absorbers in attenuation of heel strike impact.

    Science.gov (United States)

    Noe, D A; Voto, S J; Hoffmann, M S; Askew, M J; Gradisar, I A

    1993-01-01

    The capacity of the calcaneal heel pad, with and without augmentation by a polymeric shock absorbing material (Sorbothane 0050), to attenuate heel strike impulses has been studied using five fresh human cadaveric lower leg specimens. The specimens, instrumented with an accelerometer, were suspended and impacted with a hammer; a steel rod was similarly suspended and impacted. The calcaneal heel pad attenuated the peak accelerations by 80%. Attenuations of up to 93% were achieved by the shock absorbing material when tested against the steel rod; however, when tested in series with the calcaneal heel pad, the reduction in peak acceleration due to the shock absorbing material dropped to 18%. Any evaluation of the effectiveness of shock absorbing shoe materials must take into account their mechanical interaction with the body.

  13. Electrical control of charged carriers and excitons in atomically thin materials

    Science.gov (United States)

    Wang, Ke; De Greve, Kristiaan; Jauregui, Luis A.; Sushko, Andrey; High, Alexander; Zhou, You; Scuri, Giovanni; Taniguchi, Takashi; Watanabe, Kenji; Lukin, Mikhail D.; Park, Hongkun; Kim, Philip

    2018-02-01

    Electrical confinement and manipulation of charge carriers in semiconducting nanostructures are essential for realizing functional quantum electronic devices1-3. The unique band structure4-7 of atomically thin transition metal dichalcogenides (TMDs) offers a new route towards realizing novel 2D quantum electronic devices, such as valleytronic devices and valley-spin qubits8. 2D TMDs also provide a platform for novel quantum optoelectronic devices9-11 due to their large exciton binding energy12,13. However, controlled confinement and manipulation of electronic and excitonic excitations in TMD nanostructures have been technically challenging due to the prevailing disorder in the material, preventing accurate experimental control of local confinement and tunnel couplings14-16. Here we demonstrate a novel method for creating high-quality heterostructures composed of atomically thin materials that allows for efficient electrical control of excitations. Specifically, we demonstrate quantum transport in the gate-defined, quantum-confined region, observing spin-valley locked quantized conductance in quantum point contacts. We also realize gate-controlled Coulomb blockade associated with confinement of electrons and demonstrate electrical control over charged excitons with tunable local confinement potentials and tunnel couplings. Our work provides a basis for novel quantum opto-electronic devices based on manipulation of charged carriers and excitons.

  14. Study of diluting and absorber materials to control the reactivity during a postulated core meltdown accident in generation IV reactors

    International Nuclear Information System (INIS)

    Plevacova, Kamila

    2010-01-01

    In order to limit the consequences of a hypothetical core meltdown accident in Generation IV Sodium Fast Reactors, absorber materials in or near the core, such as boron carbide B 4 C, and diluting materials in the core catcher will be used to prevent recriticality within the mixture of molten oxide fuel and molten structures called corium. The aim of the PhD thesis was to select materials of both types and to understand their behaviour during their interaction with corium, from chemical and thermodynamic points of view. Concerning B 4 C, thermodynamic calculations and experiments agree with the formation of two immiscible phases at high temperature in the B 4 C - UO 2 system: one oxide and one boride. This separation of phases can reduce the efficiency of the neutrons absorption inside the molten fuel contained in the oxide phase. Moreover, volatilization of a part of the boron element can occur. According to these results, the necessary quantity of B 4 C to be introduced should be reconsidered for postulated severe accident sequence. Other solution could be the use of Eu 2 O 3 or HfO 2 as absorber material. These oxides form a solid solution with the oxide fuel. Concerning the diluting materials, mixed oxides Al 2 O 3 - HfO 2 and Al 2 O 3 - Eu 2 O 3 were preselected. These systems being completely unknown to date at high temperature in association with UO 2 , first points on the corresponding ternary phase diagrams were researched. Contrary to Al 2 O 3 - Eu 2 O 3 - UO 2 system, the Al 2 O 3 - HfO 2 - UO 2 mixture presents only one eutectic and thus only one solidification path which makes easier forecasting the behaviour of corium in the core catcher. (author)

  15. Study of diluting and absorber materials to control reactivity during a postulated core melt down accident in Generation IV reactors

    International Nuclear Information System (INIS)

    Plevacova, K.

    2010-01-01

    In order to limit the consequences of a hypothetical core meltdown accident in Generation IV Sodium Fast Reactors, absorber materials in or near the core, such as boron carbide B 4 C, and diluting materials in the core catcher will be used to prevent recriticality within the mixture of molten oxide fuel and molten structures called corium. The aim of the PhD thesis was to select materials of both types and to understand their behaviour during their interaction with corium, from chemical and thermodynamic point of view. Concerning B 4 C, thermodynamic calculations and experiments agree with the formation of two immiscible phases at high temperature in the B 4 C - UO 2 system: one oxide and one boride. This separation of phases can reduce the efficiency of the neutrons absorption inside the molten fuel contained in the oxide phase. Moreover, a volatilization of a part of the boron element can occur. According to these results, the necessary quantity of B 4 C to be introduced should be reconsidered for postulated severe accident sequence. Other solution could be the use of Eu 2 O 3 or HfO 2 as absorber material. These oxides form a solid solution with the oxide fuel. Concerning the diluting materials, mixed oxides Al 2 O 3 - HfO 2 and Al 2 O 3 - Eu 2 O 3 were preselected. These systems being completely unknown to date at high temperature in association with UO 2 , first points on the corresponding ternary phase diagrams were researched. Contrary to Al 2 O 3 - Eu 2 O 3 - UO 2 system, the Al 2 O 3 - HfO 2 - UO 2 mixture presents only one eutectic and thus only one solidification path which makes easier forecasting the behaviour of corium in the core catcher. (author) [fr

  16. Atomic collisions by neutrons-induced charged particles in water, protein and nucleic acid

    International Nuclear Information System (INIS)

    Bergman, R.

    1976-01-01

    The action of slow charged particles is peculiar in that atomic collisions are commonly invlolved. In atomic collisions, which are rare events when fast particles interact with matter, displacement of atoms and chemical bond-breakage is possible. Sufficiently energetic neutrons generate charged recoil particles in matter. Some of these are slow as compared to orbital electrons, but the energy transferred to such slow particles is generally relatively small. Yet, it contributes significantly to the dose absorbed from 0.1-30 keV neutrons. In tissue all recoils induced by neutrons of less than 30 keV are slow, and above 0.1 keV the absorbed dose due to collisiondominates over that due to capture reactions. The aim of the present paper is to identify those intervals of neutron energy in which atomic collision damage is most probable in living matter. The results of calculations presented here indicate that atomic collisions should be most significant for 0.5-3 keV neutrons. (author)

  17. Precise atomic-scale investigations of material sputtering process by light gas ions in pre-threshold energy region

    CERN Document Server

    Suvorov, A L

    2002-01-01

    Foundation and prospects of the new original technique of the sputtering yield determination of electro-conducting materials and sub-atomic layers on their surface by light gas ions the pre-threshold energy region (from 10 to 500 eV) are considered. The technique allows to identify individual surface vacancies, i.e., to count individual sputtered atoms directly. A short review of the original results obtained by using the developed techniques is given. Data are presented and analyzed concerning energy thresholds of the sputtering onset and energy dependences of sputtering yield in the threshold energy region for beryllium, tungsten, tungsten oxide, alternating tungsten-carbon layers, three carbon materials as well as for sub-atomic carbon layers on surface of certain metals at their bombardment by hydrogen, deuterium and/or helium ions

  18. Chemical composition, effective atomic number and electron density study of trommel sieve waste (TSW), Portland cement, lime, pointing and their admixtures with TSW in different proportions

    International Nuclear Information System (INIS)

    Kurudirek, Murat; Aygun, Murat; Erzeneoglu, Salih Zeki

    2010-01-01

    The trommel sieve waste (TSW) which forms during the boron ore production is considered to be a promising building material with its use as an admixture with Portland cement and is considered to be an alternative radiation shielding material, also. Thus, having knowledge on the chemical composition and radiation interaction properties of TSW as compared to other building materials is of importance. In the present study, chemical compositions of the materials used have been determined using a wavelength dispersive X-ray fluorescence spectrometer (WDXRFS). Also, TSW, some commonly used building materials (Portland cement, lime and pointing) and their admixtures with TSW have been investigated in terms of total mass attenuation coefficients (μ/ρ), photon interaction cross sections (σ t ), effective atomic numbers (Z eff ) and effective electron densities (N e ) by using X-rays at 22.1, 25 keV and γ-rays at 88 keV photon energies. Possible conclusions were drawn with respect to the variations in photon energy and chemical composition.

  19. Shock absorbing structure

    International Nuclear Information System (INIS)

    Kojima, Naoki; Matsushita, Kazuo.

    1992-01-01

    Small pieces of shock absorbers are filled in a space of a shock absorbing vessel which is divided into a plurality of sections by partitioning members. These sections function to prevent excess deformation or replacement of the fillers upon occurrence of falling accident. Since the shock absorbing small pieces in the shock absorbing vessel are filled irregularly, shock absorbing characteristics such as compression strength is not varied depending on the direction, but they exhibit excellent shock absorbing performance. They surely absorb shocks exerted on a transportation vessel upon falling or the like. If existing artificial fillers such as pole rings made of metal or ceramic and cut pieces such as alumium extrusion molding products are used as the shock absorbing pieces, they have excellent fire-proofness and cold resistance since the small pieces are inflammable and do not contain water. (T.M.)

  20. A one bath chemo-enzymatic process for preparation of absorbent cotton

    Directory of Open Access Journals (Sweden)

    A.S.M. Raja

    2016-09-01

    Full Text Available Cotton is the raw material for preparation of absorbent cotton. Raw cotton has to be subjected to scouring and bleaching processes for making it absorbent by removing the naturally present wax, protein and minerals in the fibre. The scouring is done at 115 °C using alkali followed by bleaching at boiling condition using alkaline hydrogen peroxide solution. The effluent coming out of such processes contains high COD and BOD values. Due to the stringent environmental regulation and great awareness among the public about environment, worldwide attempts have been made to develop green and sustainable chemical processing of materials. Based on the above, in the present study efforts have been made to develop an eco-friendly one bath preparatory process for the production of absorbent cotton using chemo-enzymatic formulation. The result indicated that absorbent cotton produced using the developed process fulfilled the required performance properties as per pharmacopoeia in comparable with the conventional process made one.

  1. Microstructure Analysis of Bismuth Absorbers for Transition-Edge Sensor X-ray Microcalorimeters

    Science.gov (United States)

    Yan, Daikang; Divan, Ralu; Gades, Lisa M.; Kenesei, Peter; Madden, Timothy J.; Miceli, Antonino; Park, Jun-Sang; Patel, Umeshkumar M.; Quaranta, Orlando; Sharma, Hemant; Bennett, Douglas A.; Doriese, William B.; Fowler, Joseph W.; Gard, Johnathon D.; Hays-Wehle, James P.; Morgan, Kelsey M.; Schmidt, Daniel R.; Swetz, Daniel S.; Ullom, Joel N.

    2018-03-01

    Given its large X-ray stopping power and low specific heat capacity, bismuth (Bi) is a promising absorber material for X-ray microcalorimeters and has been used with transition-edge sensors (TESs) in the past. However, distinct X-ray spectral features have been observed in TESs with Bi absorbers deposited with different techniques. Evaporated Bi absorbers are widely reported to have non-Gaussian low-energy tails, while electroplated ones do not show this feature. In this study, we fabricated Bi absorbers with these two methods and performed microstructure analysis using scanning electron microscopy and X-ray diffraction microscopy. The two types of material showed the same crystallographic structure, but the grain size of the electroplated Bi was about 40 times larger than that of the evaporated Bi. This distinction in grain size is likely to be the cause of their different spectral responses.

  2. Effective atomic numbers and electron densities of some biologically important compounds containing H, C, N and O in the energy range 145-1330 keV

    International Nuclear Information System (INIS)

    Manjunathaguru, V; Umesh, T K

    2006-01-01

    A semi-empirical relation which can be used to determine the total attenuation cross sections of samples containing H, C, N and O in the energy range 145-1332 keV has been derived based on the total attenuation cross sections of several sugars, amino acids and fatty acids. The cross sections have been measured by performing transmission experiments in a narrow beam good geometry set-up by employing a high-resolution hyperpure germanium detector at seven energies of biological importance such as 145.4 keV, 279.2 keV, 514 keV, 661.6 keV, 1115.5 keV, 1173.2 keV and 1332.1 keV. The semi-empirical relation can reproduce the experimental values within 1-2%. The total attenuation cross sections of five elements carbon, aluminium, titanium, copper and zirconium measured in the same experimental set-up at the energies mentioned above have been used in a new matrix method to evaluate the effective atomic numbers and the effective electron densities of samples such as cholesterol, fatty acids, sugars and amino acids containing H, C, N and O atoms from their effective atomic cross sections. The effective atomic cross sections are the total attenuation cross sections divided by the total number of atoms of all types in a particular sample. Further, a quantity called the effective atomic weight was defined as the ratio of the molecular weight of a sample to the total number of atoms of all types in it. The variation of the effective atomic number was systematically studied with respect to the effective atomic weight and a new semi-empirical relation for Z eff has been evolved. It is felt that this relation can be very useful to determine the effective atomic number of any sample having H, C, N and O atoms in the energy range 145-1332 keV irrespective of its chemical structure

  3. Matrix modification with silver for the electrothermal atomization of arsenic and selenium

    Science.gov (United States)

    Sanzolone, R.F.; Chao, T.T.

    1981-01-01

    Silver as a matrix modifier is shown to improve the carbon-rod atomization of both arsenic and selenium for atomic absorption spectrometry. Compared to nickel, the efficiency of silver is greater for arsenic and about the same for selenium. Silver fulfils two functions in its reaction, namely stabilization during the ashing stage and enhancement of absorbance in the final atomization. ?? 1981.

  4. Liquid carbon dioxide absorbents, methods of using the same, and related systems

    Energy Technology Data Exchange (ETDEWEB)

    O' Brien, Michael Joseph; Perry, Robert James; Lam, Tunchiao Hubert; Soloveichik, Grigorii Lev; Kniajanski, Sergei; Lewis, Larry Neil; Rubinsztajn, Malgorzata Iwona; Hancu, Dan

    2016-09-13

    A carbon dioxide absorbent composition is described, including (i) a liquid, nonaqueous silicon-based material, functionalized with one or more groups that either reversibly react with CO.sub.2 or have a high-affinity for CO.sub.2; and (ii) a hydroxy-containing solvent that is capable of dissolving both the silicon-based material and a reaction product of the silicon-based material and CO.sub.2. The absorbent may be utilized in methods to reduce carbon dioxide in an exhaust gas, and finds particular utility in power plants.

  5. High spectral selectivity for solar absorbers using a monolayer transparent conductive oxide coated on a metal substrate

    Science.gov (United States)

    Shimizu, Makoto; Suzuki, Mari; Iguchi, Fumitada; Yugami, Hiroo

    2017-05-01

    A spectrally selective absorber composed of a monolayer transparent conductive oxide (TCO) coated on a metal substrate is investigated for use in solar systems operating at temperatures higher (>973 K) than the operation temperature of conventional systems ( ˜ 673 K). This method is different from the currently used solar-selective coating technologies, such as those using multilayered and cermet materials. The spectral selective absorption property can be attributed to the inherent optical property of TCO owing to the plasma frequency and interferences between the substrates. Since spectral selectivity can be achieved using monolayered materials, the effect of atomic diffusion occurring at each layer boundary in a multilayer or cermet coatings under high-temperature conditions can be reduced. In addition, since this property is attributed to the inherent property of TCO, the precise control of the layer thickness can be omitted if the layer is sufficiently thick (>0.5 μm). The optimum TCO properties, namely, carrier density and mobility, required for solar-selective absorbers are analyzed to determine the cutoff wavelength and emittance in the infrared range. A solar absorptance of 0.95 and hemispherical emittance of 0.10 at 973 K are needed for achieving the optimum TCO properties, i.e., a carrier density of 5.5 × 1020 cm-3 and mobility of 90 cm2 V-1 s-1 are required. Optical simulations indicate that the spectrally selective absorption weakly depends on the incident angle and film thickness. The thermal stability of the fabricated absorber treated at temperatures up to 973 K for 10 h is verified in vacuum by introducing a SiO2 interlayer, which plays an important role as a diffusion barrier.

  6. PREFACE: Fourth International Symposium on Atomic Technology

    Science.gov (United States)

    Okada, Shigefumi

    2010-04-01

    The International Symposium on Atomic Technology (ISAT) is held every year. The 4th Symposium (ISAT-4) was held on November 18-19, 2009 at the Seaside Hotel MAIKO VILLA KOBE, Kobe City, Japan presided by the "Atomic Technology Project". The ISAT-4 symposium was intended to offer a forum for the discussion on the latest progress in the atomic technologies. The symposium was attended by 107 delegates. There were 10 invited and 6 oral presentations. The number of poster presentations was 69. From all the contributions, 22 papers selected through review process are contained in this volume. The "Atomic Technology Project" was started in 2006 as a joint project of three institutions; (1) the Center for Atomic and Molecular Technologies, Graduate School of Engineering, Osaka University (CAMT), (2) the Tsukuba Research Center for Interdisciplinary Materials Science, Graduate School of Pure and Applied Sciences, University of Tsukuba (TIMS) and (3) the Polyscale Technology Research Center, Research Institute for Science and Technology, Tokyo University of Science (PTRC), each of which were independently pursuing nano-technologies and was developing atomic scale operation and diagnostics, functional materials, micro processing and device. The project is funded by the Ministry of Education, Culture, Sports, Science and Technology of Japan. The goal of the project is to contribute to the development of atomic-scale science and technologies such as functional molecules, biomaterials, and quantum functions of atomic-scale structures. Shigefumi Okada Conference Chair Center for Atomic and Molecular Technologies, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita-city, Osaka 565-0871, Japan. Conference photograph Kobe photograph

  7. An overview of the development, testing, and application of composite absorbers

    International Nuclear Information System (INIS)

    Sebesta, F.; John, J.

    1995-02-01

    Although inorganic exchangers offer many advantages for removing selected elements from radioactive waste streams, few of these materials are suitable for use in packed-bed columns. We review various adaptations of inorganic exchangers for use in columns, which include granular forms of the intrinsic absorbers, absorber compounds supported on other materials, and composite absorbers that use organic or inorganic binders. An organic binding polymer of polyacrylonitrile (PAN), developed at the Czech Technical University, has been demonstrated to offer advantages. We describe general methods for preparing inorganic exchange materials, which then are incorporated into PAN-based composites. Such PAN composites have been used to remove selected radionuclides from a variety of liquid waste streams. Sixteen different PAN composites were prepared for testing at Los Alamos National Laboratory (LANL) as part of an evaluation of potential partitioning agents for remediating the liquid waste in underground storage tanks at the Hanford site near Richland, Washington. Our collaboration with LANL is expected to continue for another 2 years

  8. An overview of the development, testing, and application of composite absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Sebesta, F. [Czech Technical Univ., Brehova (Czech Republic); John, J. [Los Alamos National Lab., NM (United States)

    1995-02-01

    Although inorganic exchangers offer many advantages for removing selected elements from radioactive waste streams, few of these materials are suitable for use in packed-bed columns. We review various adaptations of inorganic exchangers for use in columns, which include granular forms of the intrinsic absorbers, absorber compounds supported on other materials, and composite absorbers that use organic or inorganic binders. An organic binding polymer of polyacrylonitrile (PAN), developed at the Czech Technical University, has been demonstrated to offer advantages. We describe general methods for preparing inorganic exchange materials, which then are incorporated into PAN-based composites. Such PAN composites have been used to remove selected radionuclides from a variety of liquid waste streams. Sixteen different PAN composites were prepared for testing at Los Alamos National Laboratory (LANL) as part of an evaluation of potential partitioning agents for remediating the liquid waste in underground storage tanks at the Hanford site near Richland, Washington. Our collaboration with LANL is expected to continue for another 2 years.

  9. New Technology in Hydrogen Absorbers for Muon Cooling Channels

    CERN Document Server

    Cummings, M A C

    2005-01-01

    Ionization cooling is the only technique fast enough to cool and focus muons for neutrino factories and muon colliders, and hydrogen is the optimal material for maximum cooling and minimal multiple scattering. Liquid hydrogen absorber R&D for the Muon Collaboration has proceeded on parallel and complementary fronts. The continuing LH2 absorber engineering and technical developments by the MuCool group conducted by ICAR* institutions (NIU, IIT and UIUC), the University of Mississippi and Oxford University, in cooperation with Fermilab, will be summarized, including results from the first hydrogen absorber tests at the newly constructed FNAL Mucool Test Area (MTA). The program includes designs for the high-powered test of an absorber prototype (external heat exchange) at the MTA which are nearing completion to be installed by summer 2005, an alternative absorber design (internal heat exchange) being finalized for the approved cooling experiment (MICE) at Rutherford-Appleton Laboratory, and a novel idea for ...

  10. Neutron physics calculation for WWER-1000 absorber element lifetime determination

    International Nuclear Information System (INIS)

    Kurakin, K.Yu.; Kushmanov, S.A.

    2009-01-01

    Absorber element with compound absorber has been operating in WWER-1000 power units since 1995. AE design meets operating organizations requirements for reliability, service life (to 10 years) and safety functions. Extension of AE service life up to 20 - 30 years by the complex of calculation and experimental work is an important problem of WWER new designs development. The paper deals with the issues related to calculation determination of main factors that influence AE service life limitation - neutron flux and fluence onto absorbing and structural materials during extended service life. (Authors)

  11. Measuring air core characteristics of a pressure-swirl atomizer via a transparent acrylic nozzle at various Reynolds numbers

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun J.; Oh, Sang Youp; Kim, Ho Y.; Yoon, Sam S. [Dept. of Mechanical, Korea University Anamdong, 5-Ga, Sungbukgu, 136-713 Seoul (Korea); James, Scott C. [Thermal/Fluid Science and Engineering, Sandia National Labs, PO Box 969, Livermore, CA 94551 (United States)

    2010-11-15

    Because of thermal fluid-property dependence, atomization stability (or flow regime) can change even at fixed operating conditions when subject to temperature change. Particularly at low temperatures, fuel's high viscosity can prevent a pressure-swirl (or simplex) atomizer from sustaining a centrifugal-driven air core within the fuel injector. During disruption of the air core inside an injector, spray characteristics outside the nozzle reflect a highly unstable, nonlinear mode where air core length, Sauter mean diameter (SMD), cone angle, and discharge coefficient variability. To better understand injector performance, these characteristics of the pressure-swirl atomizer were experimentally investigated and data were correlated to Reynolds numbers (Re). Using a transparent acrylic nozzle, the air core length, SMD, cone angle, and discharge coefficient are observed as a function of Re. The critical Reynolds numbers that distinguish the transition from unstable mode to transitional mode and eventually to a stable mode are reported. The working fluids are diesel and a kerosene-based fuel, referred to as bunker-A. (author)

  12. Heterogeneous Single-Atom Catalyst for Visible-Light-Driven High-Turnover CO2 Reduction: The Role of Electron Transfer.

    Science.gov (United States)

    Gao, Chao; Chen, Shuangming; Wang, Ying; Wang, Jiawen; Zheng, Xusheng; Zhu, Junfa; Song, Li; Zhang, Wenkai; Xiong, Yujie

    2018-03-01

    Visible-light-driven conversion of CO 2 into chemical fuels is an intriguing approach to address the energy and environmental challenges. In principle, light harvesting and catalytic reactions can be both optimized by combining the merits of homogeneous and heterogeneous photocatalysts; however, the efficiency of charge transfer between light absorbers and catalytic sites is often too low to limit the overall photocatalytic performance. In this communication, it is reported that the single-atom Co sites coordinated on the partially oxidized graphene nanosheets can serve as a highly active and durable heterogeneous catalyst for CO 2 conversion, wherein the graphene bridges homogeneous light absorbers with single-atom catalytic sites for the efficient transfer of photoexcited electrons. As a result, the turnover number for CO production reaches a high value of 678 with an unprecedented turnover frequency of 3.77 min -1 , superior to those obtained with the state-of-the-art heterogeneous photocatalysts. This work provides fresh insights into the design of catalytic sites toward photocatalytic CO 2 conversion from the angle of single-atom catalysis and highlights the role of charge kinetics in bridging the gap between heterogeneous and homogeneous photocatalysts. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Design of UV-absorbing PVDF membrane via surface-initiated AGET ATRP

    Science.gov (United States)

    Dong, Li; Liu, Xiangdong; Xiong, Zhengrong; Sheng, Dekun; Zhou, Yan; Lin, Changhong; Yang, Yuming

    2018-03-01

    Herein, PVDF membranes with excellent UV-absorbing property were first synthesized through grafting the polymerizable low-molecular-weight organic UV-absorber 2-hydroxy-4-(3-methacryloxy-2-hydroxylpropoxy) benzophenone (BPMA) onto α-bromoester-functionalized PVDF membranes via the surface-initiated activator generated by electron transfer atom transfer radical polymerization (SI-AGET ATRP). The surface initiators were immobilized by the reaction between 2-bromoisobutyryl bromide (BIBB) and the hydroxylated PVDF membranes. PVDF-g-PBPMA membranes with different grafting densities were obtained by tuning the polymerization time and the modified membranes were characterized by 1H-NMR, FT-IR, XPS, SEM, UV-vis Spectrophotometer, TGA and DSC. The experimental results indicated that PBPMA chains were successfully introduced onto PVDF membranes. Most importantly, the PVDF-g-PBPMA membranes exhibited outstanding UV-shielding property. UV-vis transmittance spectra showed that most UV light below 360 nm could be absorbed by PVDF-g-PBPMA membranes and the whole UV light region (200-400 nm) can be blocked with the reaction time increased.

  14. High Conduction Neutron Absorber to Simulate Fast Reactor Environment in an Existing Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Guillen, Donna; Greenwood, Lawrence R.; Parry, James

    2014-06-22

    A need was determined for a thermal neutron absorbing material that could be cooled in a gas reactor environment without using large amounts of a coolant that would thermalize the neutron flux. A new neutron absorbing material was developed that provided high conduction so a small amount of water would be sufficient for cooling thereby thermalizing the flux as little as possible. An irradiation experiment was performed to assess the effects of radiation and the performance of a new neutron absorbing material. Neutron fluence monitors were placed inside specially fabricated holders within a set of drop-in capsules and irradiated for up to four cycles in the Advanced Test Reactor. Following irradiation, the neutron fluence monitor wires were analyzed by gamma and x-ray spectrometry to determine the activities of the activation products. The adjusted neutron fluences were calculated and grouped into three bins – thermal, epithermal and fast to evaluate the spectral shift created by the new material. Fluence monitors were evaluated after four different irradiation periods to evaluate the effects of burn-up in the absorbing material. Additionally, activities of the three highest activity isotopes present in the specimens are given.

  15. A Characterization of the Ship-Effect in a Maritime Environment and Special Nuclear Material Detection

    Science.gov (United States)

    2015-05-18

    physics where cosmic radiation interacts preferentially with high atomic number materials to produce additional background radiation. This research...physics where cosmic radiation interacts preferentially with high atomic number materials to produce additional background radiation. A classic...LTC Michael Shannon, Director, J9-NSERC, Defense Threat Reduction Agency IV Table of Contents Abstract

  16. Nuclear reactor core having nuclear fuel and composite burnable absorber arranged for power peaking and moderator temperature coefficient control

    International Nuclear Information System (INIS)

    Kapil, S.K.

    1992-01-01

    This patent describes a burnable absorber coated nuclear fuel. It comprises a nuclear fuel substrate containing a fissionable material; and an outer burnable absorber coating applied on an outer surface of the substrate; the outer absorber coating being composed of an inner layer of a boron-bearing material except for erbium boride and an outer layer of an erbium material

  17. Electromagnetic and microwave absorbing properties of hollow ...

    Indian Academy of Sciences (India)

    bandwidth below −10 dB and minimum RL decrease with increasing thickness of HCNSs/paraffin composites. Keywords. Nanomaterials; nanospheres; CVD; electric; magnetic; microwave absorption properties. 1. Introduction. In recent years, microwave absorbing materials have attracted considerable attention because it ...

  18. An absorbent for an application to a package for a liquid radioactive isotope for medical usage

    International Nuclear Information System (INIS)

    Bang, K.S.; Lim, S.P.; Lee, J.C.; Seo, K.S.; Han, H.S.

    2004-01-01

    A radioactive isotope has to be safely transport from the producing center to the consuming center. The shipping package to safely transport the radioactive isotope should be able to withstand the prescribed conditions by law. In the field of nuclear medicine, the radioactive isotope is used in a liquid or capsule form. A Type A package, which is to transport liquid radioactive materials, shall be provided with a containment system composed of primary inner and secondary outer containment components or shall be provided with sufficient absorbent material to absorb twice the volume of the liquid contents. Hospitals prefer to use not only convenient but also re-usable packages. To apply an absorbent material to the Type A package, that is to transport liquid radioactive isotope, the free absorbency of the absorbents was estimated. In the case of a liquid with NaOH 0.4%, the free absorbency of the melanine form was the most superior at 91 g/g. In the case of a liquid with Na 0.9%, the free absorbency of the melanine form was the most excellent at 88 g/g also

  19. Scholar-activating teaching materials on quantum physics. Pt. 3. Foundations of atomic physics; Schueleraktivierende Unterrichtsmaterialien zur Quantenphysik. T. 3. Grundlagen der Atomphysik

    Energy Technology Data Exchange (ETDEWEB)

    Huebel, Horst

    2010-07-01

    Traditionally in the center of the interest on quantum physics referring to schools the question lies, whether electrons or photons are now particles or waves, a question, which is often characterized by the phrase ''wave-particle dualism'', which notoriously not exists in its original meaning. Against that by the author - on the base of important preparatory works of Kueblbeck and Mueller - a new concept of quantum physics for the school was proposed, which puts ''basic facts'' in the foreground, comparable with the Kueblbeck-Mueller ''characteristic features''. The ''basic facts'' are similar to axioms of quantum physics, by means of them a large number of experiments and phenomena can be ''explained'' at least qualitatively - in a heuristic way -. Instead of the so-called ''wave-particle dualism'' uncertainty and complementarity are put in the foreground. The new concept is in the Internet under http://www.forphys.de extensively presented with many further materials. In the partial volumes of this publication manifold and carefully elaborated teaching materials are presented, by which scholars can get themselves the partial set of quantum physics referring to schools by different methods like learning at stations, short referates, Internet-research, group puzzle, the query-sheet or the card-index method etc. In the present 3. part materials are prepared, by which scholars can get foundations of atomic physics and interpret in the sense of the ''basic facts or quantum physics''. Here deals it thus with discrete energy levels, the linear potential box, with atomic models, the atomic structure, the tunnel effect, and - because curricula it often require - also with the Schroedinger equation. The materials can also be usefully applied in other concepts.

  20. Tribology Aspect of Rubber Shock Absorbers Development

    Directory of Open Access Journals (Sweden)

    M. Banić

    2013-09-01

    Full Text Available Rubber is a very flexible material with many desirable properties Which enable its broad use in engineering practice. Rubber or rubber-metal springs are widely used as anti-vibration or anti-shock components in technical systems. Rubber-metal springs are usually realized as a bonded assembly, however especially in shock absorbers, it is possible to realize free contacts between rubber and metal parts. In previous research it authors was observed that friction between rubber and metal in such case have a significant influence on the damping characteristics of shock absorber. This paper analyzes the development process of rubber or rubber-metal shock absorbers realized free contacts between the constitutive parts, starting from the design, construction, testing and operation, with special emphasis on the development of rubber-metal springs for the buffing and draw gear of railway vehicles.

  1. Neutron absorber qualification and acceptance testing from the designer's perspective

    International Nuclear Information System (INIS)

    Bracey, W.; Chiocca, R.

    2004-01-01

    Starting in the mid 1990's, the USNRC began to require less than 100% credit for the 10B present in fixed neutron absorbers spent fuel transport packages. The current practice in the US is to use only 75% of the specified 10B in criticality safety calculations unless extensive acceptance testing demonstrates both the presence of the 10B and uniformity of its distribution. In practice, the NRC has accepted no more than 90% credit for 10B in recent years, while other national competent authorities continue to accept 100%. More recently, with the introduction of new neutron absorber materials, particularly aluminum / boron carbide metal matrix composites, the NRC has also expressed expectations for qualification testing, based in large part on Transnuclear's successful application to use a new composite material in the TN-68 storage / transport cask. The difficulty is that adding more boron than is really necessary to a metal has some negative effects on the material, reducing the ductility and the thermal conductivity, and increasing the cost. Excessive testing requirements can have the undesired effect of keeping superior materials out of spent fuel package designs, without a corresponding justification based on public safety. In European countries and especially in France, 100% credit has been accepted up to now with materials controls specified in the Safety Analysis Report (SAR): Manufacturing process approved by qualification testing Materials manufacturing controlled under a Quality Assurance system. During fabrication, acceptance testing directly on products or on representative samples. Acceptance criteria taking into account a statistical uncertainty corresponding to 3σ. The original and current bases for the reduced 10 B credit, the design requirements for neutron absorber materials, and the experience of Transnuclear and Cogema Logistics with neutron absorber testing are examined. Guidelines for qualification and acceptance testing and process controls

  2. On the atomic-number similarity of the binding energies of electrons in filled shells of elements of the periodic table

    Science.gov (United States)

    Karpov, V. Ya.; Shpatakovskaya, G. V.

    2017-03-01

    An expression for the binding energies of electrons in the ground state of an atom is derived on the basis of the Bohr-Sommerfeld quantization rule within the Thomas-Fermi model. The validity of this relation for all elements from neon to uranium is tested within a more perfect quantum-mechanical model with and without the inclusion of relativistic effects, as well as with experimental binding energies. As a result, the ordering of electronic levels in filled atomic shells is established, manifested in an approximate atomic-number similarity. It is proposed to use this scaling property to analytically estimate the binding energies of electrons in an arbitrary atom.

  3. On the atomic-number similarity of the binding energies of electrons in filled shells of elements of the periodic table

    Energy Technology Data Exchange (ETDEWEB)

    Karpov, V. Ya. [Bruk Institute of Electronic Control Machines (Russian Federation); Shpatakovskaya, G. V., E-mail: shpagalya@yandex.ru [Russian Academy of Sciences, Keldysh Institute of Applied Mathematics (Russian Federation)

    2017-03-15

    An expression for the binding energies of electrons in the ground state of an atom is derived on the basis of the Bohr–Sommerfeld quantization rule within the Thomas–Fermi model. The validity of this relation for all elements from neon to uranium is tested within a more perfect quantum-mechanical model with and without the inclusion of relativistic effects, as well as with experimental binding energies. As a result, the ordering of electronic levels in filled atomic shells is established, manifested in an approximate atomic-number similarity. It is proposed to use this scaling property to analytically estimate the binding energies of electrons in an arbitrary atom.

  4. Atom-probe field-ion-microscope mass spectrometer

    International Nuclear Information System (INIS)

    Nishikawa, Osamu

    1983-01-01

    The titled analyzer, called simply atom-probe, has been developed by combining a field ion microscope (FIM) and a mass spectrometer, and is divided into the time-of-flight type, magnetic sector type, and quadrupole type depending on the types of mass spectrometers. In this paper, the author first describes on the principle and construction of a high resolution, time-of-flight atom-probe developed and fabricated in his laboratory. The feature of the atom-probe lies in the analysis of atoms and molecules in hyper-fine structure region one by one utilizing the high resolution of FIM. It also has the advantages of directly determining the composition by a ratio of the numbers of respective ions because of a constant detection sensitivity regardless of mass numbers, of the resolution as high as single atom layer in depth direction, and of detecting the positional relationship among detected ions by the order of detection in a sample. To determine the composition in a hyperfine structure region, the limited small number of atoms and molecules in the region must be identified distinctly one by one. In the analyzed result of Ni-silicide formed by heating Si evaporated on a Ni tip at 1000 K for 5 minutes, each isotope was not only clearly separated, but also their abundance ratio was very close to the natural abundance ratio. The second half of the paper reports on the analysis of TiC promising for a cold cathode material, adsorption of CO and alcohol, and the composition and structure of silicides, as a few application examples. (Wakatsuki, Y.)

  5. A simple formulation for deriving effective atomic numbers via electron density calibration from dual-energy CT data in the human body.

    Science.gov (United States)

    Saito, Masatoshi; Sagara, Shota

    2017-06-01

    The main objective of this study is to propose a simple formulation (which we called DEEDZ) for deriving effective atomic numbers (Z eff ) via electron density (ρ e ) calibration from dual-energy (DE) CT data. We carried out numerical analysis of this DEEDZ method for a large variety of materials with known elemental compositions and mass densities using an available photon cross sections database. The new conversion approach was also applied to previously published experimental DECT data to validate its practical feasibility. We performed numerical analysis of the DEEDZ conversion method for tissue surrogates that have the same chemical compositions and mass densities as a commercial tissue-characterization phantom in order to determine the parameters necessary for the ρ e and Z eff calibrations in the DEEDZ conversion. These parameters were then applied to the human-body-equivalent tissues of ICRU Report 46 as objects of interest with unknown ρ e and Z eff . The attenuation coefficients of these materials were calculated using the XCOM photon cross sections database. We also applied the DEEDZ conversion to experimental DECT data available in the literature, which was measured for two commercial phantoms of different shapes and sizes using a dual-source CT scanner at 80 kV and 140 kV/Sn. The simulated Z eff 's were in excellent agreement with the reference values for almost all of the ICRU-46 human tissues over the Z eff range from 5.83 (gallstones-cholesterol) to 16.11 (bone mineral-hydroxyapatite). The relative deviations from the reference Z eff were within ± 0.3% for all materials, except for one outlier that presented a -3.1% deviation, namely, the thyroid. The reason for this discrepancy is that the thyroid contains a small amount of iodine, an element with a large atomic number (Z = 53). In the experimental case, we confirmed that the simple formulation with less fit parameters enable to calibrate Z eff as accurately as the existing calibration

  6. Reflection and Refraction of Light in Absorbing Media

    Science.gov (United States)

    Katsumata, Koichi; Sasaki, Shosuke

    2018-05-01

    The results of a rigorous calculation of optical phenomena in absorbing media based on Maxwell's equations are reported. In the case of an absorbing dielectric, we assume a complex dielectric constant. We find an expression for the angle of refraction as a function of the incident angle and the real and imaginary parts of the complex dielectric constant, all of which are real. The amplitudes of the reflected and transmitted waves are calculated on the same footing. These amplitudes are shown to be complex, from which we deduce the magnitude and phase change of the reflection and transmission coefficients. The same argument applies to an absorbing magnetic material if we replace the complex dielectric constant by a complex magnetic permeability.

  7. Studies on effective atomic numbers and electron densities in amino acids and sugars in the energy range 30-1333 keV

    International Nuclear Information System (INIS)

    Gowda, Shivalinge; Krishnaveni, S.; Gowda, Ramakrishna

    2005-01-01

    The effective atomic numbers and electron densities of the amino acids glycine, alanine, serine, valine, threonine, leucine, isoleucine, aspartic acid, lysine, glutamic acid, histidine, phenylalanine, arginine, tyrosine, tryptophane and the sugars arabinose, ribose, glucose, galactose, mannose, fructose, rhamnose, maltose, melibiose, melezitose and raffinose at the energies 30.8, 35.0, 81.0, 145, 276.4, 302.9, 356, 383.9, 661.6, 1173 and 1332.5 keV were calculated by using the measured total attenuation cross-sections. The interpolations of total attenuation cross-sections for photons of energy E in elements of atomic number Z was performed using the logarithmic regression analysis of the XCOM data in the photon energy region 30-1500 keV. The best-fit coefficients obtained by a piece wise interpolation method were used to find the effective atomic number and electron density of the compounds. These values are found to be in good agreement with the theoretical values calculated based on XCOM data

  8. Studies on effective atomic numbers and electron densities in amino acids and sugars in the energy range 30-1333 keV

    Energy Technology Data Exchange (ETDEWEB)

    Gowda, Shivalinge [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570 006 (India); Krishnaveni, S. [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570 006 (India); Gowda, Ramakrishna [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570 006 (India)]. E-mail: ramakrishnagowda@yahoo.com

    2005-10-15

    The effective atomic numbers and electron densities of the amino acids glycine, alanine, serine, valine, threonine, leucine, isoleucine, aspartic acid, lysine, glutamic acid, histidine, phenylalanine, arginine, tyrosine, tryptophane and the sugars arabinose, ribose, glucose, galactose, mannose, fructose, rhamnose, maltose, melibiose, melezitose and raffinose at the energies 30.8, 35.0, 81.0, 145, 276.4, 302.9, 356, 383.9, 661.6, 1173 and 1332.5 keV were calculated by using the measured total attenuation cross-sections. The interpolations of total attenuation cross-sections for photons of energy E in elements of atomic number Z was performed using the logarithmic regression analysis of the XCOM data in the photon energy region 30-1500 keV. The best-fit coefficients obtained by a piece wise interpolation method were used to find the effective atomic number and electron density of the compounds. These values are found to be in good agreement with the theoretical values calculated based on XCOM data.

  9. Use of electrothermal atomic absorption spectrometry for size profiling of gold and silver nanoparticles.

    Science.gov (United States)

    Panyabut, Teerawat; Sirirat, Natnicha; Siripinyanond, Atitaya

    2018-02-13

    Electrothermal atomic absorption spectrometry (ETAAS) was applied to investigate the atomization behaviors of gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs) in order to relate with particle size information. At various atomization temperatures from 1400 °C to 2200 °C, the time-dependent atomic absorption peak profiles of AuNPs and AgNPs with varying sizes from 5 nm to 100 nm were examined. With increasing particle size, the maximum absorbance was observed at the longer time. The time at maximum absorbance was found to linearly increase with increasing particle size, suggesting that ETAAS can be applied to provide the size information of nanoparticles. With the atomization temperature of 1600 °C, the mixtures of nanoparticles containing two particle sizes, i.e., 5 nm tannic stabilized AuNPs with 60, 80, 100 nm citrate stabilized AuNPs, were investigated and bimodal peaks were observed. The particle size dependent atomization behaviors of nanoparticles show potential application of ETAAS for providing size information of nanoparticles. The calibration plot between the time at maximum absorbance and the particle size was applied to estimate the particle size of in-house synthesized AuNPs and AgNPs and the results obtained were in good agreement with those from flow field-flow fractionation (FlFFF) and transmission electron microscopy (TEM) techniques. Furthermore, the linear relationship between the activation energy and the particle size was observed. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. The Atomic Energy Control Board

    International Nuclear Information System (INIS)

    Doern, G.B.

    1976-01-01

    This study describes and assesses the regulatory and administrative processes and procedures of the Atomic Energy Control Board, the AECB. The Atomic Energy Control Act authorized the AECB to control atomic energy materials and equipment in the national interest and to participate in measures for the international control of atomic energy. The AECB is authorized to make regulations to control atomic energy materials and equipment and to make grants in support of atomic energy research. (author)

  11. Perpetual pavement – absorbing stress and functional maintenance

    Directory of Open Access Journals (Sweden)

    Rong Gao

    2017-03-01

    Full Text Available Perpetual Pavement combines the well documented smoothness and safety advantages of asphalt with an advanced, multi-layer paving design process, that with routine maintenance, extends the useful life of a roadway. Perpetual provides long lasting road and smoothness for the construction purposes. This study has the design key points of perpetual pavement based on the idea of life cycle, which has a new direction for the new highway construction, reconstruction and expansion. First, the structure of long life pavement design is studied to analyze the effect of stress absorbing layer. Second, researches on stress absorbing layer from the aspects of raw materials, mix proportion are implemented. Third, the design index of stress absorbing layer is determined by the shear strength test. The results show that the design idea of composite perpetual pavement can be realized by reasonable design of the stress absorbing layer and carrying out the surface functional maintenance can ensure the pavement to avoid structural damage in the operation stage.

  12. Shock absorber system for nuclear reactor ice condenser compartment

    International Nuclear Information System (INIS)

    Meier, J.F.; Rudd, G.E.; Pradhan, A.V.; George, J.A.; Lippincott, H.W.; Sutherland, J.D.

    1979-01-01

    A shock absorber system was designed to absorb the energy imparted to doors in a nuclear reactor ice condenser compartment as they swing rapidly to an open position. Each shock absorber which is installed on a wall adjacent to each door is large and must absorb up to about 40,000 foot pounds of energy. The basic shock absorber component comprises foam enclosed in a synthetic fabric bag having a volume about twice the foam volume. A stainless steel knitted mesh bag of the same volume as the fabric bag, contains the fabric bag and its enclosed foam. To protect the foam and bags during construction activities at the reactor site and from the shearing action of the doors, a protective sheet metal cover is installed over the shock absorber ends and the surface to be contacted by the moving door. With the above shock absorber mounted on a wall behind each door, as the door is forcibly opened by steam pressure and air resulting from a pipe break in the reactor compartment, it swings at a high velocity into contact with the shock absorber, crushes the foam and forces it into the fabric bag excess material thus containing the foam fragmented particles, and minimizes build-up of pressure in the bag as a result of the applied compressive force

  13. A THz plasmonics perfect absorber and Fabry-Perot cavity mechanism (Conference Presentation)

    Science.gov (United States)

    Zhou, Jiangfeng; Bhattarai, Khagendra; Silva, Sinhara; Jeon, Jiyeon; Kim, Junoh; Lee, Sang Jun; Ku, Zahyun

    2016-10-01

    The plasmonic metamaterial perfect absorber (MPA) is a recently developed branch of metamaterial which exhibits nearly unity absorption within certain frequency range.[1-6] The optically thin MPA possesses characteristic features of angular-independence, high Q-factor and strong field localization that have inspired a wide range of applications including electromagnetic wave absorption,[3, 7, 8] spatial[6] and spectral[5] modulation of light,[9] selective thermal emission,[9] thermal detecting[10] and refractive index sensing for gas[11] and liquid[12, 13] targets. In this work, we demonstrate a MPA working at terahertz (THz) regime and characterize it using an ultrafast THz time-domain spectroscopy (THz-TDS). Our study reveal an ultra-thin Fabry-Perot cavity mechanism compared to the impedance matching mechanism widely adopted in previous study [1-6]. Our results also shows higher-order resonances when the cavities length increases. These higher order modes exhibits much larger Q-factor that can benefit potential sensing and imaging applications. [1] C. M. Watts, X. L. Liu, and W. J. Padilla, "Metamaterial Electromagnetic Wave Absorbers," Advanced Materials, vol. 24, pp. 98-120, Jun 19 2012. [2] M. Hedayati, F. Faupel, and M. Elbahri, "Review of Plasmonic Nanocomposite Metamaterial Absorber," Materials, vol. 7, pp. 1221-1248, 2014. [3] N. I. Landy, S. Sajuyigbe, J. J. Mock, D. R. Smith, and W. J. Padilla, "Perfect metamaterial absorber," Physical Review Letters, vol. 100, p. 207402, May 23 2008. [4] H. R. Seren, G. R. Keiser, L. Cao, J. Zhang, A. C. Strikwerda, K. Fan, et al., "Optically Modulated Multiband Terahertz Perfect Absorber," Advanced Optical Materials, vol. 2, pp. 1221-1226, 2014. [5] D. Shrekenhamer, J. Montoya, S. Krishna, and W. J. Padilla, "Four-Color Metamaterial Absorber THz Spatial Light Modulator," Advanced Optical Materials, vol. 1, pp. 905-909, 2013. [6] S. Savo, D. Shrekenhamer, and W. J. Padilla, "Liquid Crystal Metamaterial Absorber Spatial

  14. Fabrication of high efficacy selective solar absorbers

    CSIR Research Space (South Africa)

    Tile, N

    2012-03-01

    Full Text Available High efficiency tandem selective solar absorber materials of carbon in nickel oxide (C-NiO) composite were fabricated on an aluminium substrate using a simple and cost effective sol-gel process. The process involved preparation of carbon and nickel...

  15. On the calculation of Lorenz numbers for complex thermoelectric materials

    Science.gov (United States)

    Wang, Xufeng; Askarpour, Vahid; Maassen, Jesse; Lundstrom, Mark

    2018-02-01

    A first-principles informed approach to the calculation of Lorenz numbers for complex thermoelectric materials is presented and discussed. Example calculations illustrate the importance of using accurate band structures and energy-dependent scattering times. Results obtained by assuming that the scattering rate follows the density-of-states show that in the non-degenerate limit, Lorenz numbers below the commonly assumed lower limit of 2 (kB /q ) 2 can occur. The physical cause of low Lorenz numbers is explained by the shape of the transport distribution. The numerical and physical issues that need to be addressed in order to produce accurate calculations of the Lorenz number are identified. The results of this study provide a general method that should contribute to the interpretation of measurements of total thermal conductivity and to the search for materials with low Lorenz numbers, which may provide improved thermoelectric figures of merit, z T .

  16. Absorbing Property of Multi-layered Short Carbon Fiber Absorbing Coating

    OpenAIRE

    Liu, Zhaohui; Tao, Rui; Ban, Guodong; Luo, Ping

    2018-01-01

    The radar absorbing coating was prepared with short carbon fiber asabsorbent and waterborne polyurethane (WPU) as matrix resin. The coating’s absorbing property was tested with vectornetwork analyzer, using aramid honeycomb as air layer which was matched withcarbon fiber coating. The results demonstrate that the single-layered carbonfiber absorbing coating presented relatively poor absorbing property when thelayer was thin, and the performance was slightly improved after the matched airlayer ...

  17. MCSAD: Improved algorithm for Monte Carlo Simulation of Atom Displacements in solid materials

    International Nuclear Information System (INIS)

    Correa-Alfonso, C. M.; Pinnera, I.; Cruz, C. M.; Abreu, Y.; Leyva, A.

    2011-01-01

    In order to directly simulate the stochastic occurrence of atom displacements (AD) formation processes during gamma and electron irradiation, an improved Monte Carlo calculation code is presented. In MCSAD, AD processes were considered only on the basis of single elastic scattering interactions among fast primary and/or secondary electrons with matrix atoms. The AD distribution was statistically sampled and simulated in the framework of the Monte Carlo Method to perform discrete single electron scattering processes (ES), particularly those leading to AD events. As study case, the high critical temperature superconducting material YBa 2 Cu 3 O 7-x (YBCO) is presented. The AD in-depth distributions at different incident photons kinetic energies were obtained. Furthermore, the AD contribution from each atomic species to total AD distribution was achieved. In addition the AD energy profiles with the scattered electron kinetic energies were carried out. A comparison with the theoretical expressions proposed by Oen-Holmes-Cahn [1,2] is presented and discussed. (Author)

  18. Development Radar Absorber Material using Rice Husk Carbon for Anechoic Chamber Application

    Science.gov (United States)

    Zulpadrianto, Z.; Yohandri, Y.; Putra, A.

    2018-04-01

    The developments of radar technology in Indonesia are very strategic due to the vast territory and had a high-level cloud cover more than 55% of the time. The objective of this research is to develop radar technology facility in Indonesia using local natural resources. The target of this research is to present a low cost and satisfy quality of anechoic chambers. Anechoic chamber is a space designed to avoid reflection of EM waves from outside or from within the room. The reflection coefficient of the EM wave is influenced by the medium imposed by the EM wave. In laboratory experimental research has been done the development of material radar absorber using rice husk. The rice husk is activated using HCl and KOH by stirring using a magnetic stirrer for 1 Hours. The results of rice husk activation were measured using a Vector Network Analyzer by varying the thickness of the ingredients and the concentration of the activation agent. The VNA measurement is obtained reflection coefficient of -12dB and. -6.22dB for 1M HCL and KOH at thickness 10mm, respectively.

  19. Non-absorbable mesoporous silica for the development of protein sequestration therapies

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Bennett, Alfonso E., E-mail: alf.garcia@mq.edu.au [ARC Centre for Nanoscale BioPhotonics, Department of Chemistry and Bimolecular Sciences, Macquarie University, Sydney, 2109 (Australia); Ballell, Lluis, E-mail: lluis.p.ballell@gsk.com [Diseases of the Developing World, RD Alternative Discovery & Development, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, 28760, Madrid (Spain)

    2015-12-18

    While our understanding of the molecular events leading to disease onset and progression have increased exponentially, our capacity to therapeutically intervene in these events with new chemical diversity has clearly fallen short of that pace. In the quest to readdress this situation, the drug discovery sector is slowly but increasingly exploring sources of alternative chemical matter, such as the ones provided by material science and nanotechnology. While new functional nano-sized materials hold great promise for the future, our lack of understanding of the long term safety implications associated with systemic exposure as well as the unclear regulatory path ahead hamper their present impact in drug development. Paradoxically, the exploitation of novel, functionally active micron-sized, synthetic, non-absorbable chemical matter, for the treatment or prevention of a number of epidemiologically significant conditions remains clearly underexplored. A combination of pre-existing evidence and future potential indicates that micron-sized mesoporous silica materials could be an untapped source of new drug candidates. These are free from both the dreaded high attrition associated with small molecule drug discovery and the uncertainties of nano-size technologies. This, together with the coming of age of synthetic methodologies to control particle size and shape; pore size and geometry; surface chemistry, bioconjugation and formulation, open up exciting possibilities to exploit this novel chemistry-biology therapeutic interface. - Highlights: • The development of functionally active micron-sized particles in medicine is underexplored. • Mesoporous materials offer the advantage of nanostructured particles in the micron size. • Non-absorbable drugs based on such particles for enzyme inhibition are being developed. • Several conditions can be targeted such as obesity, sepsis or celiac disease.

  20. Non-absorbable mesoporous silica for the development of protein sequestration therapies

    International Nuclear Information System (INIS)

    Garcia-Bennett, Alfonso E.; Ballell, Lluis

    2015-01-01

    While our understanding of the molecular events leading to disease onset and progression have increased exponentially, our capacity to therapeutically intervene in these events with new chemical diversity has clearly fallen short of that pace. In the quest to readdress this situation, the drug discovery sector is slowly but increasingly exploring sources of alternative chemical matter, such as the ones provided by material science and nanotechnology. While new functional nano-sized materials hold great promise for the future, our lack of understanding of the long term safety implications associated with systemic exposure as well as the unclear regulatory path ahead hamper their present impact in drug development. Paradoxically, the exploitation of novel, functionally active micron-sized, synthetic, non-absorbable chemical matter, for the treatment or prevention of a number of epidemiologically significant conditions remains clearly underexplored. A combination of pre-existing evidence and future potential indicates that micron-sized mesoporous silica materials could be an untapped source of new drug candidates. These are free from both the dreaded high attrition associated with small molecule drug discovery and the uncertainties of nano-size technologies. This, together with the coming of age of synthetic methodologies to control particle size and shape; pore size and geometry; surface chemistry, bioconjugation and formulation, open up exciting possibilities to exploit this novel chemistry-biology therapeutic interface. - Highlights: • The development of functionally active micron-sized particles in medicine is underexplored. • Mesoporous materials offer the advantage of nanostructured particles in the micron size. • Non-absorbable drugs based on such particles for enzyme inhibition are being developed. • Several conditions can be targeted such as obesity, sepsis or celiac disease.

  1. Fusion process of Lennard-Jones clusters: global minima and magic numbers formation

    DEFF Research Database (Denmark)

    Solov'yov, Ilia; Solov'yov, Andrey V.; Greiner, Walter

    2004-01-01

    We present a new theoretical framework for modeling the fusion process of Lennard–Jones (LJ) clusters. Starting from the initial tetrahedral cluster configuration, adding new atoms to the system and absorbing its energy at each step, we find cluster growing paths up to the cluster size of 150 atoms...

  2. Pico-second laser materials interactions: mechanisms, material lifetime and performance optimization Ted Laurence(14-ERD-014)

    Energy Technology Data Exchange (ETDEWEB)

    Laurence, Ted A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-12-14

    Laser-induced damage with ps pulse widths straddles the transition from intrinsic, multiphoton ionization- and avalanche ionization-based ablation with fs pulses to defectdominated, thermal-based damage with ns pulses. We investigated the morphology and scaling of damage for commonly used silica and hafnia coatings as well as fused silica. Using carefully calibrated laser-induced damage experiments, in situ imaging, and high-resolution optical microscopy, atomic force microscopy, and scanning electron microscopy, we showed that defects play an important role in laser-induced damage for pulse durations as short as 1 ps. Three damage morphologies were observed: standard material ablation, ultra-high density pits, and isolated absorbers. For 10 ps and longer, the isolated absorbers limited the damage performance of the coating materials. We showed that damage resulting from the isolated absorbers grows dramatically with subsequent pulses for sufficient fluences. For hafnia coatings, we used electric field modeling and experiments to show that isolated absorbers near the surface were affected by the chemical environment (vacuum vs. air) for pulses as short as 10 ps. Coupled with the silica results, these results suggested that improvements in the performance in the 10 -60 ps range have not reached fundamental limits. These findings motivate new efforts, including a new SI LDRD in improving the laser-damage performance of multi-layer dielectric coatings. A damage test facility for ps pulses was developed and automated, and was used for testing production optics for ARC. The resulting software was transferred to other laser test facilities for fs pulses and multiple wavelengths with 30 ps pulses. Additionally, the LDRD supported the retention and promotion of an important staff scientist in high-resolution dynamic microscopy and laser-damage testing.

  3. The Atomic energy basic law

    International Nuclear Information System (INIS)

    1979-01-01

    The law aims to secure future energy resources, push forward progress of science and advancement of industry for welfare of the mankind and higher standard of national life by helping research, development and utilization of atomic power. Research, development and utilization of atomic power shall be limited to the peaceful purpose with emphasis laid on safety and carried on independently under democratic administration. Basic concepts and terms are defined, such as: atomic power; nuclear fuel material; nuclear raw material; reactor and radiation. The Atomic Energy Commission and the Atomic Energy Safety Commission shall be set up at the Prime Minister's Office deliberately to realize national policy of research, development and utilization of atomic power and manage democratic administration for atomic energy. The Atomic Energy Commission shall plan, consider and decide matters concerning research, development and utilization of atomic energy. The Atomic Energy Safety Commission shall plan, consider and decide issues particularly concerning safety securing among such matters. The Atomic Energy Research Institute shall be founded under the governmental supervision to perform research, experiment and other necessary affairs for development of atomic energy. The Power Reactor and Nuclear Fuel Development Corporation shall be established likewise to develop fast breeding reactor, advanced thermal reactor and nuclear fuel materials. Development of radioactive minerals, control of nuclear fuel materials and reactors and measures for patent and invention concerning atomic energy, etc. are stipulated respectively. (Okada, K.)

  4. Computerized simulation of the mechanical behavior of wood-filled shock absorbers of radioactive materials transport casks; Rechnerische Simulation des mechanischen Verhaltens von holzgefuellten Stossdaempfern von Transportbehaeltern fuer radioaktive Stoffe

    Energy Technology Data Exchange (ETDEWEB)

    Neumann, Martin; Wille, Frank [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany)

    2011-07-01

    In Germany the mechanical component inspection of transport containers for radioactive materials is performed by BAM (Bundesanstalt fuer Materialforschung und -pruefung) under consideration of national and international standards and guidelines. Experimental and calculative (analytical and numerical) techniques combined with material and/or component testing are the basis of assessment concepts according the state of the art. The authors describe the experiences of BAM concerning assessment and description of the mechanical behavior of shock absorbing components, including modeling strategies, material models, drop tests and experiment-calculation comparison. Energy absorbing components are used to reduce the impact forces at the container in case of a transport accident. In Germany wood filled thin-walled constructions are used. The deformation behavior of the wood is a main part of the calculative simulation procedures in comparison with experimental tests.

  5. Apparatus and method for the measurement of neutron moderating or absorbing properties of objects

    International Nuclear Information System (INIS)

    Untermyer, S.I.

    1981-01-01

    An apparatus and method for measuring the neutron moderating or absorbing properties of objects or materials is disclosed in which a fast neutron source cooperates with a neutron absorbing material which reduces the energy of the fast neutrons by inelastic scattering so that they can be readily thermalized by a moderator. A thermal neutron detector is disposed adjacent the material and serves to detect thermal neutrons emitted by a moderator placed to receive and thermalize the reduced energy neutrons. A material whose absorption is to be measured is placed between a moderator and the detector

  6. 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)

  7. First-principles investigation of neutron-irradiation-induced point defects in B4C, a neutron absorber for sodium-cooled fast nuclear reactors

    Science.gov (United States)

    You, Yan; Yoshida, Katsumi; Yano, Toyohiko

    2018-05-01

    Boron carbide (B4C) is a leading candidate neutron absorber material for sodium-cooled fast nuclear reactors owing to its excellent neutron-capture capability. The formation and migration energies of the neutron-irradiation-induced defects, including vacancies, neutron-capture reaction products, and knocked-out atoms were studied by density functional theory calculations. The vacancy-type defects tend to migrate to the C–B–C chains of B4C, which indicates that the icosahedral cage structures of B4C have strong resistance to neutron irradiation. We found that lithium and helium atoms had significantly lower migration barriers along the rhombohedral (111) plane of B4C than perpendicular to this plane. This implies that the helium and lithium interstitials tended to follow a two-dimensional diffusion regime in B4C at low temperatures which explains the formation of flat disk like helium bubbles experimentally observed in B4C pellets after neutron irradiation. The knocked-out atoms are considered to be annihilated by the recombination of the close pairs of self-interstitials and vacancies.

  8. Atoms, molecules and optical physics 1. Atoms and spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hertel, Ingolf V.; Schulz, Claus-Peter

    2015-09-01

    This is the first volume of textbooks on atomic, molecular and optical physics, aiming at a comprehensive presentation of this highly productive branch of modern physics as an indispensable basis for many areas in physics and chemistry as well as in state of the art bio- and material-sciences. It primarily addresses advanced students (including PhD students), but in a number of selected subject areas the reader is lead up to the frontiers of present research. Thus even the active scientist is addressed. This volume 1 provides the canonical knowledge in atomic physics together with basics of modern spectroscopy. Starting from the fundamentals of quantum physics, the reader is familiarized in well structured chapters step by step with the most important phenomena, models and measuring techniques. The emphasis is always on the experiment and its interpretation, while the necessary theory is introduced from this perspective in a compact and occasionally somewhat heuristic manner, easy to follow even for beginners.

  9. The containment and an absorbent evaluation for a package for a liquid radioactive isotope

    Energy Technology Data Exchange (ETDEWEB)

    Bang, K. S.; Lee, J. C.; Kim, D. H.; Hwang, C. S.; Kim, H. J.; Seo, K. S

    2005-03-01

    Radioactive isotopes must be safely transported from the production centre to the point of use. The shipping package to safely transport radioactive isotopes should be able to withstand the conditions prescribed by law. A type a package, which is used to transport liquid radioactive materials, should have a containment system comprising a primary inner and a secondary outer containment or it should be provided with a sufficiently absorbent material to absorb twice the volume of the liquid contents. Accordingly, an absorbent material for use in a Type A package to transport a liquid radioactive isotope was estimated. To estimate the integrity of containment, the leakage tests for a containment system for a Type A package for domestic and abroad expert were conducted.

  10. Deposition and characterization of spray pyrolysed p-type Cu2SnS3 thin film for potential absorber layer of solar cell

    Science.gov (United States)

    Thiruvenkadam, S.; Sakthi, P.; Prabhakaran, S.; Chakravarty, Sujay; Ganesan, V.; Rajesh, A. Leo

    2018-06-01

    Thin film of ternary Cu2SnS3 (CTS), a potential absorber layer for solar cells was successfully deposited by chemical spray pyrolysis technique. The GIXRD pattern revealed that the film having tetragonal Cu2SnS3 phase with the preferential orientation along (112), (200), (220) and (312) plane and it is further confirmed using Raman spectroscopy by the existence of Raman peak at 320 cm-1. Atomic Force Microscopy (AFM) was used to estimate the surface roughness of 28.8 nm. The absorption coefficient was found to be greater than the order of 105 cm-1 and bandgap of 1.70 eV. Hall effect measurement indicates the p type nature of the film with a hole concentration of 1.03 × 1016cm-3 and a hall mobility of 404 cm2/V. The properties of CTS thin film confirmed suitable to be a potential absorber layer material for photovoltaic applications.

  11. Materials-by-design: computation, synthesis, and characterization from atoms to structures

    Science.gov (United States)

    Yeo, Jingjie; Jung, Gang Seob; Martín-Martínez, Francisco J.; Ling, Shengjie; Gu, Grace X.; Qin, Zhao; Buehler, Markus J.

    2018-05-01

    In the 50 years that succeeded Richard Feynman’s exposition of the idea that there is ‘plenty of room at the bottom’ for manipulating individual atoms for the synthesis and manufacturing processing of materials, the materials-by-design paradigm is being developed gradually through synergistic integration of experimental material synthesis and characterization with predictive computational modeling and optimization. This paper reviews how this paradigm creates the possibility to develop materials according to specific, rational designs from the molecular to the macroscopic scale. We discuss promising techniques in experimental small-scale material synthesis and large-scale fabrication methods to manipulate atomistic or macroscale structures, which can be designed by computational modeling. These include recombinant protein technology to produce peptides and proteins with tailored sequences encoded by recombinant DNA, self-assembly processes induced by conformational transition of proteins, additive manufacturing for designing complex structures, and qualitative and quantitative characterization of materials at different length scales. We describe important material characterization techniques using numerous methods of spectroscopy and microscopy. We detail numerous multi-scale computational modeling techniques that complements these experimental techniques: DFT at the atomistic scale; fully atomistic and coarse-grain molecular dynamics at the molecular to mesoscale; continuum modeling at the macroscale. Additionally, we present case studies that utilize experimental and computational approaches in an integrated manner to broaden our understanding of the properties of two-dimensional materials and materials based on silk and silk-elastin-like proteins.

  12. Recommended method for measurement of absorbency of superabsorbent polymers in cement-based materials

    DEFF Research Database (Denmark)

    Esteves, Luis Pedro

    2015-01-01

    —laser diffraction particle size analysis, and it allows an easy and reliable measurement of the absorbency of superabsorbent polymers. It is shown in detail how both the definition of the exposure liquid and the definition of the system of SAP particles can be selected so that absorbency can be experimentally...... so that the properties of concrete with superabsorbent polymers can be better controlled in practice. In this paper, a technique that can be potentially used as a standard method is developed. The method is based on a measurement technique validated through an international standard procedure...

  13. Passive microrheology of soft materials with atomic force microscopy: A wavelet-based spectral analysis

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Torres, C.; Streppa, L. [CNRS, UMR5672, Laboratoire de Physique, Ecole Normale Supérieure de Lyon, 46 Allée d' Italie, Université de Lyon, 69007 Lyon (France); Arneodo, A.; Argoul, F. [CNRS, UMR5672, Laboratoire de Physique, Ecole Normale Supérieure de Lyon, 46 Allée d' Italie, Université de Lyon, 69007 Lyon (France); CNRS, UMR5798, Laboratoire Ondes et Matière d' Aquitaine, Université de Bordeaux, 351 Cours de la Libération, 33405 Talence (France); Argoul, P. [Université Paris-Est, Ecole des Ponts ParisTech, SDOA, MAST, IFSTTAR, 14-20 Bd Newton, Cité Descartes, 77420 Champs sur Marne (France)

    2016-01-18

    Compared to active microrheology where a known force or modulation is periodically imposed to a soft material, passive microrheology relies on the spectral analysis of the spontaneous motion of tracers inherent or external to the material. Passive microrheology studies of soft or living materials with atomic force microscopy (AFM) cantilever tips are rather rare because, in the spectral densities, the rheological response of the materials is hardly distinguishable from other sources of random or periodic perturbations. To circumvent this difficulty, we propose here a wavelet-based decomposition of AFM cantilever tip fluctuations and we show that when applying this multi-scale method to soft polymer layers and to living myoblasts, the structural damping exponents of these soft materials can be retrieved.

  14. Final Report on Atomic Database Project

    International Nuclear Information System (INIS)

    Yuan, J.; Gui, Z.; Moses, G.A.

    2006-01-01

    Atomic physics in hot dense plasmas is essential for understanding the radiative properties of plasmas either produced terrestrially such as in fusion energy research or in space such as the study of the core of the sun. Various kinds of atomic data are needed for spectrum analysis or for radiation hydrodynamics simulations. There are many atomic databases accessible publicly through the web, such as CHIANTI (an atomic database for spectroscopic diagnostics for astrophysical plasmas) from Naval Research Laboratory [1], collaborative development of TOPbase (The Opacity Project for astrophysically abundant elements) [2], NIST atomic spectra database from NIST [3], TOPS Opacities from Los Alamos National Laboratory [4], etc. Most of these databases are specific to astrophysics, which provide energy levels, oscillator strength f and photoionization cross sections for astrophysical elements ( Z=1-26). There are abundant spectrum data sources for spectral analysis of low Z elements. For opacities used for radiation transport, TOPS Opacities from LANL is the most valuable source. The database provides mixed opacities from element for H (Z=1) to Zn (Z=30) The data in TOPS Opacities is calculated by the code LEDCOP. In the Fusion Technology Institute, we also have developed several different models to calculate atomic data and opacities, such as the detailed term accounting model (DTA) and the unresolved transition array (UTA) model. We use the DTA model for low-Z materials since an enormous number of transitions need to be computed for medium or high-Z materials. For medium and high Z materials, we use the UTA model which simulates the enormous number of transitions by using a single line profile to represent a collection of transition arrays. These models have been implemented in our computing code JATBASE and RSSUTA. For plasma populations, two models are used in JATBASE, one is the local thermodynamic equilibrium (LTE) model and the second is the non-LTE model. For the

  15. Angular momentum coupling in atom-atom collisions

    International Nuclear Information System (INIS)

    Grosser, J.

    1986-01-01

    The coupling between the electronic angular momentum and the rotating atom-atom axis in the initial or the final phase of an atom-atom collision is discussed, making use of the concepts of radial and rotational (Coriolis) coupling between different molecular states. The description is based on a limited number of well-understood approximations, and it allows an illustrative geometric representation of the transition from the body fixed to the space fixed motion of the electrons. (orig.)

  16. Fluctuation-induced forces on an atom near a photonic topological material

    Science.gov (United States)

    Silveirinha, Mário G.; Gangaraj, S. Ali Hassani; Hanson, George W.; Antezza, Mauro

    2018-02-01

    We theoretically study the Casimir-Polder force on an atom in an arbitrary initial state in a rather general electromagnetic environment wherein the materials may have a nonreciprocal bianisotropic dispersive response. It is shown that under the Markov approximation the force has resonant and nonresonant contributions. We obtain explicit expressions for the optical force both in terms of the system Green function and of the electromagnetic modes. We apply the theory to the particular case wherein a two-level system interacts with a topological gyrotropic material, showing that the nonreciprocity enables exotic light-matter interactions and the opportunity to sculpt and tune the Casimir-Polder forces on the nanoscale. With a quasistatic approximation, we obtain a simple analytical expression for the optical force and unveil the crucial role of surface plasmons in fluctuation-induced forces. Finally, we derive the Green function for a gyrotropic material half-space in terms of a Sommerfeld integral.

  17. Thermal Evaluation of Storage Rack with an Advanced Neutron Absorber during Normal Operation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hee-Jae; Kim, Mi-Jin; Sohn, Dong-Seong [UNIST, Ulsan (Korea, Republic of)

    2016-10-15

    The storage capacity of the domestic wet storage site is expected to reach saturation from Hanbit in 2024 to Sin-wolseong in 2038 and accordingly management alternatives are urgently taken. Since installation of the dense rack is considered in the short term, it is necessary to urgently develop an advanced neutron absorber which can be applied to a spent nuclear fuel storage facility. Neutron absorber is the material for controlling the reactivity. A material which has excellent thermal neutron absorption ability, high strength and corrosion resistance must be selected as the neutron absorber. Existing neutron absorbers are made of boron which has a good thermal absorption ability such as BORAL and METAMIC. However, possible problems have been reported in using the boron-based neutron absorber for wet storage facility. Gadolinium is known to have higher neutron absorption cross-section than that of boron. And the strength of duplex stainless steel is about 1.5 times higher than stainless steel 304 which has been frequently used as a structural material. Therefore, duplex stainless steel which contains gadolinium is in consideration as an advanced neutron absorber. Temperature distribution is shown in figure 4. In pool bottom region near the inlet shows a relatively low tendency and heat generated from the fuel assemblies is transmitted to the pool upper region by the vertical flow. Also, temperature gradient appear in rack structures for the axial direction and temperature is uniformly distributed in the pool upper region. Table 1 presents the calculated results. The maximum temperature is 306.63K and does not exceed the 333.15K (60℃). The maximum temperature of the neutron absorber is 306.48K.

  18. Selective solar absorber coating research at the CSIR (South Africa)

    CSIR Research Space (South Africa)

    Roro, Kittessa T

    2011-05-01

    Full Text Available A sol-gel technique has been established at a laboratory scale for low cost production of high efficient selective solar absorbers comprising a composite material of nano-structured carbon in a nickel oxide matrix. In order for these materials...

  19. A method optimization study for atomic absorption ...

    African Journals Online (AJOL)

    Sadia Ata

    2014-04-24

    Apr 24, 2014 ... Manufacturer brand Win 2.1 software was used for data inte- gration and processing. ... reagents and analyst) is suitable for the intended application. The % relative standard deviation for absorbance ... flame atomic absorption spectrometry. Table 2 Linearity data for analysis of zinc in insulin using AAS.

  20. Quality control of diagnostic radiology to reduce absorbed dose of patients in Iran

    International Nuclear Information System (INIS)

    Aghahadi, Bahman.

    1996-01-01

    In order to reduce absorbed dose, to increase the image quality and to reduce the numbers of rejected films various quality control parameters were applied to X ray machines. These parameter are Kilo Volt peak, Milli Ampere, Exposure Time Focal Film Distance, Inherent Filters, Additional Filters Half Value Layer, Processor Condition, Cassettes. To evaluate and to apply these parameters in diagnostic radiological centers, ten hospitals were selected and a total number of 12 X ray machines were kept under quality control program. Considering different kinds of diagnostic radiology examination and to compare the dose before and after implementation of a quality control program, two kinds of examinations include in chest and abdomen examinations were considered. For each X ray machine, ten patients and for all selected centers, 120 patients were selected for chest examination and 120 patients for abdomen examinations; before and after implementation of quality control program, a total of 480 patients were selected randomly to be controlled. Base on different examinations carried out, it was concluded that both exposure conditions and general situations in radiological centers were not acceptable. The dosimetry results show that the average ski dose for chest and abdomen examinations were 0.28 m Gy and 4.23 Gy respectively. Before implementation of quality control step to reduce the surface skin dose, quality control parameters were applied and the exposure conditions were imposed. On average the absorbed doses for chest and abdomen examination were decreased to 79% and 61% respectively after the implementation of the program. From dose reduction point of view, the results of a part of this project which made by co-operation of International Atomic Energy Agency showed that Iran acquired the first grade for chest examination and second grade for abdomen examination. Base on the results obtained, the number of patients under chest and abdomen examination were 4041588 and

  1. Atom probe microanalysis: Principles and applications to materials problems

    International Nuclear Information System (INIS)

    Miller, M.K.; Smith, G.D.W.

    1987-01-01

    A historical background and general introduction to field emission and field-ionization, field-ion microscopy, and the atom probe is given. Physical principles of field ion microscopy are explained, followed by interpretation of images. Types of atom probes are discussed, as well as the instrumentation used in atomic probe microanalysis. Methods of atom probe analysis and data representation are covered, along with factors affecting performance and statistical analysis of atom probe data. Finally, some case studies and special types of analyses are presented

  2. Mass attenuation coefficient (μ/ρ), effective atomic number (Z{sub eff}) and measurement of x-ray energy spectra using based calcium phosphate biomaterials: a comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes Z, M. A.; Da Silva, T. A.; Nogueira, M. S. [Centro de Desenvolvimento da Tecnologia Nuclear / CNEN, Pte. Antonio Carlos 6627, Belo Horizonte 31270-901, Minas Gerais (Brazil); Goncalves Z, E., E-mail: madelon@cdtn.br [Pontifice Catholic University of Minas Gerais, Av. Dom Jose Gaspar 500, Belo Horizonte 30535-901, Minas Gerais (Brazil)

    2015-10-15

    In dentistry, alveolar bone regeneration procedures using based calcium phosphate biomaterials have been shown effective. However,there are not reports in the literature of studies the interaction of low energy radiation in these biomaterials used as attenuator and not being then allowed a comparison between the theoretical values and experimental.The objective of this study was to determine the interaction of radiation parameters of four dental biomaterials - BioOss, Cerasorb M Dental, Straumann Boneceramic and Osteogen for diagnostic radiology qualities. As a material and methods, the composition of the biomaterials was determined by the analytical techniques. The samples with 0.181 cm to 0,297 cm thickness were experimentally used as attenuators for the measurement of the transmitted X-rays spectra in X-ray equipment with 50 to 90 kV range by spectrometric system comprising the Cd Te detector. After this procedure, the mass attenuation coefficient, the effective atomic number were determined and compared between all the specimens analyzed, using the program WinXCOM in the range of 10 to 200 keV. In all strains examined observed that the energy spectrum of x-rays transmitted through the BioOss has the mean energy slightly smaller than the others biomaterials for close thickness. The μ/ρ and Z{sub eff} of the biomaterials showed its dependence on photon energy and atomic number of the elements of the material analyzed. It is concluded according to the methodology employed in this study that the measurements of x-ray spectrum, μ/ρ and Z{sub eff} using biomaterials as attenuators confirmed that the thickness, density, composition of the samples, the incident photon energy are factors that determine the characteristics of radiation in a tissue or equivalent material. (Author)

  3. Fidelity imaging for atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ghosal, Sayan, E-mail: ghos0087@umn.edu; Salapaka, Murti, E-mail: murtis@umn.edu [Nanodynamics Systems Laboratory, Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

    2015-01-05

    Atomic force microscopy is widely employed for imaging material at the nanoscale. However, real-time measures on image reliability are lacking in contemporary atomic force microscopy literature. In this article, we present a real-time technique that provides an image of fidelity for a high bandwidth dynamic mode imaging scheme. The fidelity images define channels that allow the user to have additional authority over the choice of decision threshold that facilitates where the emphasis is desired, on discovering most true features on the sample with the possible detection of high number of false features, or emphasizing minimizing instances of false detections. Simulation and experimental results demonstrate the effectiveness of fidelity imaging.

  4. Acoustic Properties of Absorbent Asphalts

    Science.gov (United States)

    Trematerra, Amelia; Lombardi, Ilaria

    2017-08-01

    Road traffic is one of the greater cause of noise pollution in urban centers; a prolonged exposure to this source of noise disturbs populations subjected to it. In this paper is reported a study on the absorbent coefficients of asphalt. The acoustic measurements are carried out with a impedance tube (tube of Kundt). The sample are measured in three conditions: with dry material (traditional), “wet” asphalt and “dirty” asphalt.

  5. Atomic layer deposition of nanostructured materials

    CERN Document Server

    Pinna, Nicola

    2012-01-01

    Atomic layer deposition, formerly called atomic layer epitaxy, was developed in the 1970s to meet the needs of producing high-quality, large-area fl at displays with perfect structure and process controllability. Nowadays, creating nanomaterials and producing nanostructures with structural perfection is an important goal for many applications in nanotechnology. As ALD is one of the important techniques which offers good control over the surface structures created, it is more and more in the focus of scientists. The book is structured in such a way to fi t both the need of the expert reader (du

  6. The atomic energy basic law

    International Nuclear Information System (INIS)

    1977-01-01

    The law establishes clearly the principles that Japan makes R and D, and utilizations of atomic energy only for the peaceful purposes. All the other laws and regulations concerning atomic energy are based on the law. The first chapter lays down the above mentioned objective of the law, and gives definitions of basic concepts and terms, such as atomic energy, nuclear fuel material, nuclear source material, nuclear reactor and radiation. The second chapter provides for the establishment of Atomic Energy Commission which conducts plannings and investigations, and also makes decisions concerning R and D, and utilizations of atomic energy. The third chapter stipulates for establishment of two government organizations which perform R and D of atomic energy developments including experiments and demonstrations of new types of reactors, namely, Atomic Energy Research Institute and Power Reactor and Nuclear Fuel Development Corporation. Chapters from 4th through 8th provide for the regulations on development and acquisition of the minerals containing nuclear source materials, controls on nuclear fuel materials and nuclear reactors, administrations of the patents and inventions concerning atomic energy, and also prevention of injuries due to radiations. The last 9th chapter requires the government and its appointee to compensate the interested third party for damages in relation to the exploitation of nuclear source materials. (Matsushima, A.)

  7. Effects of increased collagen-matrix density on the mechanical properties and in vivo absorbability of hydroxyapatite-collagen composites as artificial bone materials

    Energy Technology Data Exchange (ETDEWEB)

    Yunoki, Shunji [Life Science Group, Tokyo Metropolitan Industrial Technology Research Institute, 2-11-1 Fukasawa, Setagaya-ku, Tokyo 158-0081 (Japan); Sugiura, Hiroaki; Kondo, Eiji; Yasuda, Kazunori [Department of Sports Medicine and Joint Surgery, Graduate School of Medicine, Hokkaido University, Kita-15 Nishi-7, Sapporo, Hokkaido 060-8638 Japan (Japan); Ikoma, Toshiyuki; Tanaka, Junzo, E-mail: yunoki.shunji@iri-tokyo.jp [Department of Metallurgy and Ceramics Science, 2-12-1-S7-1, Ookayama, Meguro-ku, Tokyo 152-8550 (Japan)

    2011-02-15

    The aim of this study was to evaluate the effects of increased collagen-matrix density on the mechanical properties and in vivo absorbability of porous hydroxyapatite (HAp)-collagen composites as artificial bone materials. Seven types of porous HAp-collagen composites were prepared from HAp nanocrystals and dense collagen fibrils. Their densities and HAp/collagen weight ratios ranged from 122 to 331 mg cm{sup -3} and from 20/80 to 80/20, respectively. The flexural modulus and strength increased with an increase in density, reaching 2.46 {+-} 0.48 and 0.651 {+-} 0.103 MPa, respectively. The porous composites with a higher collagen-matrix density exhibited much higher mechanical properties at the same densities, suggesting that increasing the collagen-matrix density is an effective way of improving the mechanical properties. It was also suggested that other structural factors in addition to collagen-matrix density are required to achieve bone-like mechanical properties. The in vivo absorbability of the composites was investigated in bone defects of rabbit femurs, demonstrating that the absorption rate decreased with increases in the composite density. An exhaustive increase in density is probably limited by decreases in absorbability as artificial bones.

  8. Effects of increased collagen-matrix density on the mechanical properties and in vivo absorbability of hydroxyapatite-collagen composites as artificial bone materials

    International Nuclear Information System (INIS)

    Yunoki, Shunji; Sugiura, Hiroaki; Kondo, Eiji; Yasuda, Kazunori; Ikoma, Toshiyuki; Tanaka, Junzo

    2011-01-01

    The aim of this study was to evaluate the effects of increased collagen-matrix density on the mechanical properties and in vivo absorbability of porous hydroxyapatite (HAp)-collagen composites as artificial bone materials. Seven types of porous HAp-collagen composites were prepared from HAp nanocrystals and dense collagen fibrils. Their densities and HAp/collagen weight ratios ranged from 122 to 331 mg cm -3 and from 20/80 to 80/20, respectively. The flexural modulus and strength increased with an increase in density, reaching 2.46 ± 0.48 and 0.651 ± 0.103 MPa, respectively. The porous composites with a higher collagen-matrix density exhibited much higher mechanical properties at the same densities, suggesting that increasing the collagen-matrix density is an effective way of improving the mechanical properties. It was also suggested that other structural factors in addition to collagen-matrix density are required to achieve bone-like mechanical properties. The in vivo absorbability of the composites was investigated in bone defects of rabbit femurs, demonstrating that the absorption rate decreased with increases in the composite density. An exhaustive increase in density is probably limited by decreases in absorbability as artificial bones.

  9. Lead-Free Hybrid Perovskite Absorbers for Viable Application: Can We Eat the Cake and Have It too?

    Science.gov (United States)

    Liang, Lusheng; Gao, Peng

    2018-02-01

    Many years since the booming of research on perovskite solar cells (PSCs), the hybrid perovskite materials developed for photovoltaic application form three main categories since 2009: (i) high-performance unstable lead-containing perovskites, (ii) low-performance lead-free perovskites, and (iii) moderate performance and stable lead-containing perovskites. The search for alternative materials to replace lead leads to the second group of perovskite materials. To date, a number of these compounds have been synthesized and applied in photovoltaic devices. Here, lead-free hybrid light absorbers used in PV devices are focused and their recent developments in related solar cell applications are reviewed comprehensively. In the first part, group 14 metals (Sn and Ge)-based perovskites are introduced with more emphasis on the optimization of Sn-based PSCs. Then concerns on halide hybrids of group 15 metals (Bi and Sb) are raised, which are mainly perovskite derivatives. At the same time, transition metal Cu-based perovskites are also referred. In the end, an outlook is given on the design strategy of lead-free halide hybrid absorbers for photovoltaic applications. It is believed that this timely review can represent our unique view of the field and shed some light on the direction of development of such promising materials.

  10. Corundum-based transparent infrared absorbers

    KAUST Repository

    Schwingenschlögl, Udo

    2009-10-01

    Hypothetical corundum-based compounds are studied by electronic structure calculations. One quarter of the Al atoms in Al2O3 is replaced by a 3d transition metal from the M = Ti, ..., Zn (d1, ..., d9) series. Structure optimisations are performed for all the M-Al2O3 compounds and the electronic states are evaluated. Due to the M substitutes, narrow partially filled bands are formed at the Fermi energy. Beyond, for M = Ni and M = Cu the optical properties of Al2O3 in the visible range are conserved, while for M = Ti, ..., Co the systems form high accuracy optical filters. Since the compounds absorb the infrared radiation, the M = Ni and M = Cu systems are good candidates for heat-protective coatings. © 2009 Elsevier B.V. All rights reserved.

  11. Studies on properties of low atomic number ceramics as limiter materials for fusion applications

    International Nuclear Information System (INIS)

    Thiele, B.A.; Hoven, H.; Koizlik, K.; Linke, J.; Wallure, E.

    1986-01-01

    The present study deals with thermal shock and erosion-redeposition behaviour of low-Z-bulk-ceramics: SiC, SiC + Si, SiC + 3% Al, SiC + 2% AlN, AlN, Si 3 N 4 , BN with graphite as reference material. Also included are substrate-coating systems: TiC coated graphite, Cr 2 C 3 coated graphite and TiN on Inconel. The properties are being investigated by electron beam and in-pile fusion machine tests in the KFA-Tokamak machine Textor. The electron-beam tests showed that sublimation was the dominant damaging effect for graphite, BN and SiN 4 . Materials with mediocre thermo-mechanical properties, such as SiC and AlN, showed cracks. The highest energy density values were tolerated by specimens of SiC alloyed with 2% AlN. In general, the in pile behaviour of the ceramics was comparable with the electron beam tests: BN and SiC + 2% AlN are at present regarded as the prime candidates for future irradiation tests. (author)

  12. Interfacial engineering of two-dimensional nano-structured materials by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Zhuiykov, Serge, E-mail: serge.zhuiykov@ugent.be [Ghent University Global Campus, Department of Applied Analytical & Physical Chemistry, Faculty of Bioscience Engineering, 119 Songdomunhwa-ro, Yeonsu-Gu, Incheon 406-840 (Korea, Republic of); Kawaguchi, Toshikazu [Global Station for Food, Land and Water Resources, Global Institution for Collaborative Research and Education, Hokkaido University, N10W5 Kita-ku, Sapporo, Hokkaido 060-0810 (Japan); Graduate School of Environmental Science, Hokkaido University, N10W5 Kita-ku, Sapporo, Hokkaido 060-0810 (Japan); Hai, Zhenyin; Karbalaei Akbari, Mohammad; Heynderickx, Philippe M. [Ghent University Global Campus, Department of Applied Analytical & Physical Chemistry, Faculty of Bioscience Engineering, 119 Songdomunhwa-ro, Yeonsu-Gu, Incheon 406-840 (Korea, Republic of)

    2017-01-15

    Highlights: • Advantages of atomic layer deposition technology (ALD) for two-dimensional nano-crystals. • Conformation of ALD technique and chemistry of precursors. • ALD of semiconductor oxide thin films. • Ultra-thin (∼1.47 nm thick) ALD-developed tungsten oxide nano-crystals on large area. - Abstract: Atomic Layer Deposition (ALD) is an enabling technology which provides coating and material features with significant advantages compared to other existing techniques for depositing precise nanometer-thin two-dimensional (2D) nanostructures. It is a cyclic process which relies on sequential self-terminating reactions between gas phase precursor molecules and a solid surface. ALD is especially advantageous when the film quality or thickness is critical, offering ultra-high aspect ratios. ALD provides digital thickness control to the atomic level by depositing film one atomic layer at a time, as well as pinhole-free films even over a very large and complex areas. Digital control extends to sandwiches, hetero-structures, nano-laminates, metal oxides, graded index layers and doping, and it is perfect for conformal coating and challenging 2D electrodes for various functional devices. The technique’s capabilities are presented on the example of ALD-developed ultra-thin 2D tungsten oxide (WO{sub 3}) over the large area of standard 4” Si substrates. The discussed advantages of ALD enable and endorse the employment of this technique for the development of hetero-nanostructure 2D semiconductors with unique properties.

  13. Design of a five-band terahertz perfect metamaterial absorber using two resonators

    Science.gov (United States)

    Meng, Tianhua; Hu, Dan; Zhu, Qiaofen

    2018-05-01

    We present a polarization-insensitive five-band terahertz perfect metamaterial absorber composed of two metallic circular rings and a metallic ground film separated by a dielectric layer. The calculated results show that the absorber has five distinctive absorption bands whose peaks are greater than 99% on average. The physical origin of the absorber originates from the combination of dipolar, hexapolar, and surface plasmon resonance of the patterned metallic structure, which is different from the work mechanism of previously reported absorbers. In addition, the influence of the structural parameters on the absorption spectra is analyzed to further confirm the origin of the five-band absorption peaks. The proposed absorber has potential applications in terahertz imaging, refractive index sensing, and material detecting.

  14. Nanostructured materials for hydrogen storage

    Science.gov (United States)

    Williamson, Andrew J.; Reboredo, Fernando A.

    2007-12-04

    A system for hydrogen storage comprising a porous nano-structured material with hydrogen absorbed on the surfaces of the porous nano-structured material. The system of hydrogen storage comprises absorbing hydrogen on the surfaces of a porous nano-structured semiconductor material.

  15. Nitrile-functionalized tertiary amines as highly efficient and reversible SO2 absorbents

    International Nuclear Information System (INIS)

    Hong, Sung Yun; Kim, Heehwan; Kim, Young Jin; Jeong, Junkyo; Cheong, Minserk; Lee, Hyunjoo; Kim, Hoon Sik; Lee, Je Seung

    2014-01-01

    Highlights: • Nitrile-functionalized tertiary amines physically and reversibly absorb SO 2 . • Tertiary alkanolamines chemically and irreversibly absorb SO 2 through OH group. • SO 2 absorption modes were studied by spectroscopy and computational calculations. -- Abstract: Three different types of nitrile-functionalized amines, including 3-(N,N-diethylamino)propionitrile (DEAPN), 3-(N,N-dibutylamino)propionitrile (DBAPN), and N-methyl-N,N-dipropionitrile amine (MADPN) were synthesized, and their SO 2 absorption performances were evaluated and compared with those of hydroxy-functionalized amines such as N,N-diethyl-N-ethanol amine (DEEA), N,N-dibutyl-N-ethanol amine (DBEA), and N-methyl-N,N-diethanol amine (MDEA). Absorption–desorption cycle experiments clearly demonstrate that the nitrile-functionalized amines are more efficient than the hydroxy-functionalized amines in terms of absorption rate and regenerability. Computational calculations with DBEA and DBAPN revealed that DBEA bearing a hydroxyethyl group chemically interacts with SO 2 through oxygen atom, forming an ionic compound with a covalently bound -OSO 2 − group. On the contrary, DBAPN bearing a nitrile group physically interacts with SO 2 through the nitrogen and the hydrogen atoms of the two methylene groups adjacent to the amino and nitrile functionalities

  16. Determination of Absorbed Dose to Water for Leksell Gamma Knife Unit

    International Nuclear Information System (INIS)

    Hrsak, H.

    2013-01-01

    Because of geometry of photon beams in Leksell Gamma Knife Unit (LGK), there are several technical problems in applying standard protocols for determination of absorbed dose to water (Dw). Currently, Dw in LGK unit, measured at the center of spherical plastic phantom, is used for dose calculation in LGK radiosurgery. Treatment planning software (LGP TPS) accepts this value as a measurement in water and since plastic phantom has higher electron density than water, this leads to systematic errors in dose calculation. To reduce these errors, a photon attenuation correction (PAC) method was applied. For that purpose, measurements of absorbed dose in a center of three different plastic phantoms with 16 cm diameter (ABS - acrylonitrile butadiene styrene, PMMA - polymethyl metacrylate, PMMA + teflon - polytetrafluoroethylene 5 mm shell) were made with ionization chamber (Semiflex, PTW Freiburg). For measured dose values, PAC to water was applied based on electron density (ED) and equivalent water depths (EWD) of the plastic phantoms. The relation between CT number and ED was determined by measuring CT number of standard CT to ED phantom (CIRS Model 062 Phantom). Absorbed dose in plastic phantoms was 2.5 % lower than calculated dose in water for ABS phantom and more than 5.5 % lower for PMMA and PMMA+teflon phantom. Calculated dose in water showed more consistent values for all three phantoms (max. difference 2.6 %). EWD for human cranial bones and brain has value close to the EWD of ABS phantom, which makes this phantom most suitable for dose measurements in clinical application. In LGK radiosurgery determination of errors related to the difference of phantom materials should not be neglected and measured dose should be corrected before usage for patient treatment dose calculation.(author)

  17. Large-angle illumination STEM: Toward three-dimensional atom-by-atom imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, Ryo, E-mail: ishikawa@sigma.t.u-tokyo.ac.jp [Institute of Engineering Innovation, University of Tokyo, Tokyo 113-8656 (Japan); Lupini, Andrew R. [Materials Science & Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Hinuma, Yoyo [Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501 (Japan); Pennycook, Stephen J. [Department of Materials Science and Engineering, The University of Tennessee, 328 Ferris Hall, Knoxville, TN 37996 (United States)

    2015-04-15

    To fully understand and control materials and their properties, it is of critical importance to determine their atomic structures in all three dimensions. Recent revolutionary advances in electron optics – the inventions of geometric and chromatic aberration correctors as well as electron source monochromators – have provided fertile ground for performing optical depth sectioning at atomic-scale dimensions. In this study we theoretically demonstrate the imaging of top/sub-surface atomic structures and identify the depth of single dopants, single vacancies and the other point defects within materials by large-angle illumination scanning transmission electron microscopy (LAI-STEM). The proposed method also allows us to measure specimen properties such as thickness or three-dimensional surface morphology using observations from a single crystallographic orientation. - Highlights: • We theoretically demonstrate 3D near-atomic depth resolution imaging by large-angle illumination STEM. • This method can be useful to identify the depth of single dopants, single vacancies within materials. • This method can be useful to determine reconstructed surface atomic structures.

  18. Determination of tissue equivalent materials of a physical 8-year-old phantom for use in computed tomography

    International Nuclear Information System (INIS)

    Akhlaghi, Parisa; Miri Hakimabad, Hashem; Rafat Motavalli, Laleh

    2015-01-01

    This paper reports on the methodology applied to select suitable tissue equivalent materials of an 8-year phantom for use in computed tomography (CT) examinations. To find the appropriate tissue substitutes, first physical properties (physical density, electronic density, effective atomic number, mass attenuation coefficient and CT number) of different materials were studied. Results showed that, the physical properties of water and polyurethane (as soft tissue), B-100 and polyvinyl chloride (PVC) (as bone) and polyurethane foam (as lung) agree more with those of original tissues. Then in the next step, the absorbed doses in the location of 25 thermoluminescent dosimeters (TLDs) as well as dose distribution in one slice of phantom were calculated for original and these proposed materials by Monte Carlo simulation at different tube voltages. The comparisons suggested that at tube voltages of 80 and 100 kVp using B-100 as bone, water as soft tissue and polyurethane foam as lung is suitable for dosimetric study in pediatric CT examinations. In addition, it was concluded that by considering just the mass attenuation coefficient of different materials, the appropriate tissue equivalent substitutes in each desired X-ray energy range could be found. - Highlights: • A methodology to select tissue equivalent materials for use in CT was proposed. • Physical properties of different materials were studied. • TLDs dose and dose distribution were calculated for original and proposed materials. • B-100 as bone, and water as soft tissue are best substitute materials at 80 kVp. • Mass attenuation coefficient is determinant for selecting best tissue substitutes

  19. Numerical and analytical approaches to an advection-diffusion problem at small Reynolds number and large Péclet number

    Science.gov (United States)

    Fuller, Nathaniel J.; Licata, Nicholas A.

    2018-05-01

    Obtaining a detailed understanding of the physical interactions between a cell and its environment often requires information about the flow of fluid surrounding the cell. Cells must be able to effectively absorb and discard material in order to survive. Strategies for nutrient acquisition and toxin disposal, which have been evolutionarily selected for their efficacy, should reflect knowledge of the physics underlying this mass transport problem. Motivated by these considerations, in this paper we discuss the results from an undergraduate research project on the advection-diffusion equation at small Reynolds number and large Péclet number. In particular, we consider the problem of mass transport for a Stokesian spherical swimmer. We approach the problem numerically and analytically through a rescaling of the concentration boundary layer. A biophysically motivated first-passage problem for the absorption of material by the swimming cell demonstrates quantitative agreement between the numerical and analytical approaches. We conclude by discussing the connections between our results and the design of smart toxin disposal systems.

  20. Solubilization of advanced ceramic materials controlled by chemical analysis by means of atomic absorption spectroscopy

    International Nuclear Information System (INIS)

    Amarante Junior, A.

    1992-01-01

    This paper purpose is to show the techniques used in chemical analysis laboratory at Escola SENAI Mario Amato in the ceramic nucleus for opening and solubilization of Advanced Ceramic materials, where the elements in its majority are determined for atomic absorption spectroscopy. (author)

  1. Studies on effective atomic number, electron density and kerma for some fatty acids and carbohydrates

    International Nuclear Information System (INIS)

    Manohara, S R; Hanagodimath, S M; Gerward, L

    2008-01-01

    The effective atomic number, Z eff , the effective electron density, N el , and kerma have been calculated for some fatty acids and carbohydrates for photon interaction in the extended energy range from 1 keV to 100 GeV using an accurate database of photon-interaction cross sections and the WinXCom program. The significant variation of Z eff and N el is due to the variations in the dominance of different interaction processes in different energy regions. The maximum values of Z eff and N el are found in the low-energy range, where photoelectric absorption is the main interaction process. The minimum values of Z eff and N el are found at intermediate energies, typically 0.05 MeV eff is equal to the mean atomic number of the bio-molecule. Wherever possible, the calculations are compared with experimental results. A comparison is also made with the single values of the Z eff and N el provided by the program XMuDat. It is also observed that carbohydrates have a larger kerma than fatty acids in the low-energy region, where photoelectric absorption dominates. In contrast, fatty acids have a larger kerma than carbohydrates in the MeV range, where Compton scattering is the main interaction process. (note)

  2. Cell-killing efficiency and number of platinum atoms binding to DNA, RNA and protein molecules of HeLa cells treated with combinations of hyperthermia and carboplatin

    International Nuclear Information System (INIS)

    Akaboshi, M.; Kawai, K.; Tanaka, Y.; Takada, J.; Sumino, T.

    1999-01-01

    The effect of hyperthermia on the cell killing efficiency of Pt atoms binding to DNA, RNA and protein molecules of HeLa cells treated with cis-diamine(1,1-cyclobutanedicarboxylato)platinum(II) (CBDCA) was examined. HeLa S-3 cells were treated with 195m Pt-radiolabeled CBDCA for 60 minutes at various temperatures, and the relationship between the lethal effect and the number of Pt atoms binding to DNA, RNA and proteins was examined. The mean lethal concentration (D 0 ) of carboplatin for a 60 min-treatment at 0, 25, 37, 40, 42 and 44 deg C was 671.2, 201.5, 67.3, 33.4, 20.2 and 15.6 μM, respectively. By using identically treated cells, the number of Pt-atoms combined with DNA, RNA and protein molecules were determined in the subcellular fractions. Thus, the D 0 's given as the drug concentrations were replaced with the number of Pt-atoms combined in each fraction. Then, the cell-killing efficiency of the Pt atom was expressed as the reciprocal of the number of Pt-atoms combined and was calculated for each molecule. The efficiency for DNA molecules was 0.699, 1.42, 2.65, 4.84, 7.74 and 8.28x10 4 nucleotides, respectively, for the conditions described above. From 0 to 44 deg C, the cell-killing efficiency of Pt atoms increased by a factor of 11.9. (author)

  3. Determination of the Rb atomic number density in dense rubidium vapors by absorption measurements of Rb2 triplet bands

    International Nuclear Information System (INIS)

    Horvatic, Vlasta; Veza, Damir; Niemax, Kay; Vadla, Cedomil

    2008-01-01

    A simple and accurate way of determining atom number densities in dense rubidium vapors is presented. The method relies on the experimental finding that the reduced absorption coefficients of the Rb triplet satellite bands between 740 nm and 750 nm and the triplet diffuse band between 600 nm and 610 nm are not temperature dependent in the range between 600 K and 800 K. Therefore, the absolute values of the reduced absorption coefficients of these molecular bands can provide accurate information about atomic number density of the vapor. The rubidium absorption spectrum was measured by spatially resolved white-light absorption in overheated rubidium vapor generated in a heat pipe oven. The absolute values for the reduced absorption coefficients of the triplet bands were determined at lower vapor densities, by using an accurate expression for the reduced absorption coefficient in the quasistatic wing of the Rb D1 line, and measured triplet satellite bands to the resonance wing optical depth ratio. These triplet satellite band data were used to calibrate in absolute scale the reduced absorption coefficients of the triplet diffuse band at higher temperatures. The obtained values for the reduced absorption coefficient of these Rb molecular features can be used for accurate determination of rubidium atomic number densities in the range from about 5 x 10 16 cm -3 to 1 x 10 18 cm -3

  4. Working group written presentation: Atomic oxygen

    International Nuclear Information System (INIS)

    Leger, L.J.; Visentine, J.T.

    1989-01-01

    Earlier Shuttle flight experiments have shown NASA and SDIO spacecraft designed for operation in low-Earth orbit (LEO) must take into consideration the highly oxidative characteristics of the ambient flight environment. Materials most adversely affected by atomic oxygen interactions include organic films, advanced (carbon-based) composites, thermal control coatings, organic-based paints, optical coatings, and thermal control blankets commonly used in spacecraft applications. Earlier results of NASA flight experiments have shown prolonged exposure of sensitive spacecraft materials to the LEO environment will result in degraded systems performance or, more importantly, lead to requirements for excessive on-orbit maintenance, with both conditions contributing significantly to increased mission costs and reduced mission objectives. Flight data obtained from previous Space Shuttle missions and results of the Solar Max recovery mission are limited in terms of atomic oxygen exposure and accuracy of fluence estimates. The results of laboratory studies to investigate the long-term (15 to 30 yrs) effects of AO exposure on spacecraft surfaces are only recently available, and qualitative correlations of laboratory results with flight results have been obtained for only a limited number of materials. The working group recommended the most promising ground-based laboratories now under development be made operational as soon as possible to study the full-life effects of atomic oxygen exposure on spacecraft systems

  5. Applied acoustics concepts, absorbers, and silencers for acoustical comfort and noise control alternative solutions, innovative tools, practical examples

    CERN Document Server

    Fuchs, Helmut V

    2013-01-01

    The author gives a comprehensive overview of materials and components for noise control and acoustical comfort. Sound absorbers must meet acoustical and architectural requirements, which fibrous or porous material alone can meet. Basics and applications are demonstrated, with representative examples for spatial acoustics, free-field test facilities and canal linings. Acoustic engineers and construction professionals will find some new basic concepts and tools for developments in order to improve acoustical comfort. Interference absorbers, active resonators and micro-perforated absorbers of different materials and designs complete the list of applications.

  6. Eliminating the non-Gaussian spectral response of X-ray absorbers for transition-edge sensors

    Science.gov (United States)

    Yan, Daikang; Divan, Ralu; Gades, Lisa M.; Kenesei, Peter; Madden, Timothy J.; Miceli, Antonino; Park, Jun-Sang; Patel, Umeshkumar M.; Quaranta, Orlando; Sharma, Hemant; Bennett, Douglas A.; Doriese, William B.; Fowler, Joseph W.; Gard, Johnathon D.; Hays-Wehle, James P.; Morgan, Kelsey M.; Schmidt, Daniel R.; Swetz, Daniel S.; Ullom, Joel N.

    2017-11-01

    Transition-edge sensors (TESs) as microcalorimeters for high-energy-resolution X-ray spectroscopy are often fabricated with an absorber made of materials with high Z (for X-ray stopping power) and low heat capacity (for high resolving power). Bismuth represents one of the most compelling options. TESs with evaporated bismuth absorbers have shown spectra with undesirable and unexplained low-energy tails. We have developed TESs with electroplated bismuth absorbers over a gold layer that are not afflicted by this problem and that retain the other positive aspects of this material. To better understand these phenomena, we have studied a series of TESs with gold, gold/evaporated bismuth, and gold/electroplated bismuth absorbers, fabricated on the same die with identical thermal coupling. We show that the bismuth morphology is linked to the spectral response of X-ray TES microcalorimeters.

  7. Evaluation of Absorbents for Compatibility with Site Generated Hazardous and Mixed Liquid Wastes

    International Nuclear Information System (INIS)

    Oji, L.N.

    2002-01-01

    SRS Solid Waste requested SRTC to perform a literature-based evaluation of sorbents, which are compatible with hazardous mixed waste being generated on site. Polypropylene-based materials and ground corn cob (Toxi-dry), because of their compatibility with the Consolidated Incinerator Facility (CIF) process, are the only two spill stabilization agents which are recommended for use on site (IS manual, Waste Acceptance Criteria 3.18). While ensuring minimal potential for undesired reactions between spills and spill control agents, Solid Waste wants to increase the number of site approved absorbents to give waste generators more flexibility in choosing liquid spill immobilization agents

  8. Distributions of 15 elements on 58 absorbers from simulated Hanford Double-Shell Slurry Feed (DSSF)

    International Nuclear Information System (INIS)

    Marsh, S.F.; Svitra, Z.V.; Bowen, S.M.

    1994-11-01

    As part of the Hanford Tank Waste Remediation System program at Los Alamos, we evaluated 58 commercially available or experimental absorber materials for their ability to remove hazardous components from high-level waste. These absorbers included cation and anion exchange resins, inorganic exchangers, composite absorbers, pillared layered materials, and a series of liquid extractants sorbed on porous support-beads. We tested these absorbers with a solution that simulates Hanford double-shell slurry feed (DSSF) (pH 14.0). To this simulant solution we added the appropriate radionuclides and used gamma spectrometry to measure fission products (Ce, Cs, Sr, Tc, and Y), actinides (U and Am), and matrix elements (Cr, Co, Fe, Mn, Ni, V, Zn, and Zr). For each of 870 element/absorber combinations, we measured distribution coefficients for dynamic contact periods of 30 min, 2 h, and 6 h to obtain information about sorption kinetics. On the basis of these 2610 measured distribution coefficients, we determined that many of the tested absorbers may be suitable for processing DSSF solutions

  9. Sodium antimony sulfide (NaSbS2: Turning an unexpected impurity into a promising, environmentally friendly novel solar absorber material

    Directory of Open Access Journals (Sweden)

    Siti Utari Rahayu

    2016-11-01

    Full Text Available We present a novel absorber material—NaSbS2—for solar cells. NaSbS2 is formed as an unexpected byproduct in the chemical synthesis of Sb2S3. However, NaSbS2 has many attractive features for a solar material. Here single phase NaSbS2 nanoparticles were synthesized through solution processing. NaSbS2 semiconductor-sensitized solar cells were demonstrated for the first time. The best cell yielded Jsc = 10.76 mA/cm2, Voc = 0.44 V, FF = 48.6%, and efficiency η = 2.30% under 1 sun. At the reduced 0.1 sun, the η increased to 3.18%—a respectable η for a new solar material.

  10. Design of a nonlinear torsional vibration absorber

    Science.gov (United States)

    Tahir, Ammaar Bin

    larger than that in the latter. A nonlinear absorber design has been proposed comprising of thin beams as elastic elements. The geometric configuration of the proposed design has been shown to provide cubic stiffness nonlinearity in torsion. The values of design variables, namely the strength of nonlinearity alpha and torsional stiffness kalpha, were obtained by optimizing dimensions and material properties of the beams for a maximum vibration energy dissipation in the nonlinear absorber. A parametric study has also been conducted to analyze the effect of the magnitude of excitation provided to the system on the performance of a nonlinear absorber. It has been shown that the nonlinear absorber turns out to be more effective in terms of energy dissipation as compared to a linear absorber with an increase in the excitation level applied to the system.

  11. Induced absorption and stimulated emission in a driven two-level atom

    International Nuclear Information System (INIS)

    Mavroyannis, C.

    1992-01-01

    We have considered the induced processes that occur in a driven two-level atom, where a laser photon is absorbed and emitted by the ground and by the excited states of the atom, respectively. In the low-intensity limit of the laser field, the induced spectra arising when a laser photon is absorbed by the ground state of the atom consist of two peaks describing induced absorption and stimulated-emission processes, respectively, where the former prevails over the latter. Asymmetry of the spectral lines occurs at off-resonance and its extent depends on the detuning of the laser field. The physical. process where a laser photon is emitted by the excited state is the reverse of that arising from the absorption of a laser photon by the ground state of the atom. The former differs from the latter in that the emission of a laser photon by the excited state occurs in the low frequency regime and that the stimulated-emission process prevails over that of the induced absorption. In this case, amplification of ultrashort pulses is likely to occur without the need of population inversion between the optical transitions. The computed spectra are graphically presented and discussed. (author)

  12. A Study of the Anechoic Performance of Rice Husk-Based, Geometrically Tapered, Hollow Absorbers

    Directory of Open Access Journals (Sweden)

    Muhammad Nadeem Iqbal

    2014-01-01

    Full Text Available Although solid, geometrically tapered microwave absorbers are preferred due to their better performance, they are bulky and must have a thickness on the order of λ or more. The goal of this study was to design lightweight absorbers that can reduce the electromagnetic reflections to less than −10 dB. We used a very simple approach; two waste materials, that is, rice husks and tire dust in powder form, were used to fabricate two independent samples. We measured and used their dielectric properties to determine and compare the propagation constants and quarter-wave thickness. The quarter-wave thickness for the tire dust was 3 mm less than that of the rice husk material, but we preferred the rice-husk material. This preference was based on the fact that our goal was to achieve minimum backward reflections, and the rice-husk material, with its low dielectric constant, high loss factor, large attenuation per unit length, and ease of fabrication, provided a better opportunity to achieve that goal. The performance of the absorbers was found to be better (lower than −20 dB, and comparison of the results proved that the hollow design with 58% less weight was a good alternative to the use of solid absorbers.

  13. Development of an innovative solar absorber

    Science.gov (United States)

    Goodchild, Gavin

    Solar thermal systems have great potential to replace or reduce the dependence of conventional fossil fuel based heating technologies required for space and water heating. Specifically solar domestic hot water systems can contribute 50-75% of the annual thermal load. To date residential users have been slow to purchase and install systems, primarily due to the large monetary investment required to purchase and install a system. Recent innovations in materials design and manufacturing techniques, offer opportunities for the development of absorber plate designs that have the potential to reduce cost, increase efficiency and reduce payback periods. Consequently, this design study was conducted in conjunction with industrial partners to develop an improved absorber based on roll bond manufacturing that can be produced at reduced cost with comparable or greater thermal efficiency.

  14. Comparison between Two Bromine Containing Free Radical Initiators in PRESAGE®

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hyeonsuk; Ryu, Dongmin; Ye, Sung-Joon [Seoul National University, Seoul (Korea, Republic of)

    2016-10-15

    PRESAGE® is an optically clear 3-D polyurethane dosimeter which contains a halogenated carbon as a free radical initiator and leucomalachite dye. The change of the optical density is known to be linear with respect to the absorbed dose and the sensitivity is related to the carbon–halogen bond dissociation energy of the free radical initiator. Although there are some studies regarding free radical initiators and dye materials, there’s a lack of reports about the effect of other elements like LMG solvent which can be added when there’s a difficulty mixing materials. Also, there are some studies about comparison between free radicals with different kind of halogen atoms but there’s a lack of studies of comparison between initiators with the same halogen atom. In this experiments, two kinds of halocarbon free radical initiator with the same halogen atom (bromine) as well as the effect of the LMG solvent were studied to use the dosimeter as a therapeutic purpose. Effective atomic numbers were also calculated. The initiators with the same halogen atom, CBr{sub 4} and C{sub 2}H{sub 2}Br{sub 4}, reacted totally differently. CBr{sub 4} was more sensitive to the radiation and emitted maximum 4 times more free radicals upon irradiation with no additional effective atomic number but the absorbance after irradiation was highly variable with time. For stable measurement, C{sub 2}H{sub 2}Br{sub 4} would be more appropriate as a free radical initiator.

  15. IAEA activities on atomic, molecular and plasma-material interaction data for fusion

    Science.gov (United States)

    Braams, Bastiaan J.; Chung, Hyun-Kyung

    2013-09-01

    The IAEA Atomic and Molecular Data Unit (http://www-amdis.iaea.org/) aims to provide internationally evaluated and recommended data for atomic, molecular and plasma-material interaction (A+M+PMI) processes in fusion research. The Unit organizes technical meetings and coordinates an A+M Data Centre Network (DCN) and a Code Centre Network (CCN). In addition the Unit organizes Coordinated Research Projects (CRPs), for which the objectives are mixed between development of new data and evaluation and recommendation of existing data. In the area of A+M data we are placing new emphasis in our meeting schedule on data evaluation and especially on uncertainties in calculated cross section data and the propagation of uncertainties through structure data and fundamental cross sections to effective rate coefficients. Following a recent meeting of the CCN it is intended to use electron scattering on Be, Ne and N2 as exemplars for study of uncertainties and uncertainty propagation in calculated data; this will be discussed further at the presentation. Please see http://www-amdis.iaea.org/CRP/ for more on our active and planned CRPs, which are concerned with atomic processes in core and edge plasma and with plasma interaction with beryllium-based surfaces and with irradiated tungsten.

  16. Atomic Layer Deposition on Porous Materials: Problems with Conventional Approaches to Catalyst and Fuel Cell Electrode Preparation

    Directory of Open Access Journals (Sweden)

    Tzia Ming Onn

    2018-03-01

    Full Text Available Atomic layer deposition (ALD offers exciting possibilities for controlling the structure and composition of surfaces on the atomic scale in heterogeneous catalysts and solid oxide fuel cell (SOFC electrodes. However, while ALD procedures and equipment are well developed for applications involving flat surfaces, the conditions required for ALD in porous materials with a large surface area need to be very different. The materials (e.g., rare earths and other functional oxides that are of interest for catalytic applications will also be different. For flat surfaces, rapid cycling, enabled by high carrier-gas flow rates, is necessary in order to rapidly grow thicker films. By contrast, ALD films in porous materials rarely need to be more than 1 nm thick. The elimination of diffusion gradients, efficient use of precursors, and ligand removal with less reactive precursors are the major factors that need to be controlled. In this review, criteria will be outlined for the successful use of ALD in porous materials. Examples of opportunities for using ALD to modify heterogeneous catalysts and SOFC electrodes will be given.

  17. Atom Skimmers and Atom Lasers Utilizing Them

    Science.gov (United States)

    Hulet, Randall; Tollett, Jeff; Franke, Kurt; Moss, Steve; Sackett, Charles; Gerton, Jordan; Ghaffari, Bita; McAlexander, W.; Strecker, K.; Homan, D.

    2005-01-01

    Atom skimmers are devices that act as low-pass velocity filters for atoms in thermal atomic beams. An atom skimmer operating in conjunction with a suitable thermal atomic-beam source (e.g., an oven in which cesium is heated) can serve as a source of slow atoms for a magneto-optical trap or other apparatus in an atomic-physics experiment. Phenomena that are studied in such apparatuses include Bose-Einstein condensation of atomic gases, spectra of trapped atoms, and collisions of slowly moving atoms. An atom skimmer includes a curved, low-thermal-conduction tube that leads from the outlet of a thermal atomic-beam source to the inlet of a magneto-optical trap or other device in which the selected low-velocity atoms are to be used. Permanent rare-earth magnets are placed around the tube in a yoke of high-magnetic-permeability material to establish a quadrupole or octupole magnetic field leading from the source to the trap. The atoms are attracted to the locus of minimum magnetic-field intensity in the middle of the tube, and the gradient of the magnetic field provides centripetal force that guides the atoms around the curve along the axis of the tube. The threshold velocity for guiding is dictated by the gradient of the magnetic field and the radius of curvature of the tube. Atoms moving at lesser velocities are successfully guided; faster atoms strike the tube wall and are lost from the beam.

  18. Comparison of iron and tungsten absorber structures for an analog hadron calorimeter

    International Nuclear Information System (INIS)

    Guenter, Clemens

    2015-05-01

    Future electron-positron-collider experiments will require unprecedented jet-energy resolution to complete their physics programs. This can only be achieved with novel approaches to calorimetry. One of these novel approaches is the Particle Flow Algorithm, which uses the best suited sub-detector to measure the energy of the particles produced by the electronpositron collision. The CALICE Collaboration evaluates different read-out technologies for Particle Flow Calorimeters. This thesis describes the comparison of two different absorber materials, iron and tungsten, for the CALICE Analog Hadron Calorimeter. It is described how test-beam data, that have been recorded in the range from 2 GeV to 10 GeV with the Analog Hadron Calorimeter are calibrated, and how samples are selected containing showers from just one particle type. The data are then compared to simulations, and the remaining disagreement between data and simulation is discussed. The validated simulations are then used to decompose the showers into different fractions. These fractions are compared for the two absorber materials to understand the impact of the absorber material choice on the calorimeter performance.

  19. A new method to determine the mixing state of light absorbing carbonaceous using the measured aerosol optical properties and number size distributions

    Directory of Open Access Journals (Sweden)

    N. Ma

    2012-03-01

    Full Text Available In this paper, the mixing state of light absorbing carbonaceous (LAC was investigated with a two-parameter aerosol optical model and in situ aerosol measurements at a regional site in the North China Plain (NCP. A closure study between the hemispheric backscattering fraction (HBF measured by an integrating nephelometer and that calculated with a modified Mie model was conducted. A new method was proposed to retrieve the ratio of the externally mixed LAC mass to the total mass of LAC (rext-LAC based on the assumption that the ambient aerosol particles were externally mixed and consisted of a pure LAC material and a core-shell morphology in which the core is LAC and the shell is a less absorbing material. A Monte Carlo simulation was applied to estimate the overall influences of input parameters of the algorithm to the retrieved rext-LAC. The diurnal variation of rext-LAC was analyzed and the PartMC-MOSAIC model was used to simulate the variation of the aerosol mixing state. Results show that, for internally mixed particles, the assumption of core-shell mixture is more appropriate than that of homogenous mixture which has been widely used in aerosol optical calculations. A significant diurnal pattern of the retrieved rext-LAC was found, with high values during the daytime and low values at night. The consistency between the retrieved rext-LAC and the model results indicates that the diurnal variation of LAC mixing state is mainly caused by the diurnal evolution of the mixing layer.

  20. Design considerations for application of metallic honeycomb as an energy absorber

    International Nuclear Information System (INIS)

    Lee, W.H.; Roemer, R.E.

    1980-01-01

    Design for postulated accidents in nuclear power plants often requires mitigation of impact to safety-related structures. Plastically designed, energy absorbing mechanisms are often used in the design of such mitigating structures. Metallic honeycomb is the most efficient, practical, energy-absorbing material currently in use. Recent tests indicate that its use in this application, however, presents some unique design and fabrication problems. The paper presents the results of static and dynamic crush tests concerned with the effect of impact velocity, material properties, cell density, loading configuration, and overall pad geometry. Specific design recommendations are made in each area, and suggestions are provided to improve fabrication techniques and minimize subsequent problems