WorldWideScience

Sample records for burnable absorbers design

  1. Conceptual design of quadriso particles with europium burnable absorber in HTRS.

    Energy Technology Data Exchange (ETDEWEB)

    Talamo, A.; Nuclear Engineering Division

    2010-05-18

    In High Temperature Reactors, burnable absorbers are utilized to manage the excess reactivity at the early stage of the fuel cycle. In this study QUADRISO particles are proposed to manage the initial xcess reactivity of High Temperature Reactors. The QUADRISO concept synergistically couples the decrease of the burnable poison with the decrease of the fissile materials at the fuel particle level. This echanism is set up by introducing a burnable poison layer around the fuel kernel in ordinary TRISO particles or by mixing the burnable poison with any of the TRISO coated layers. At the beginning of life, the nitial excess reactivity is small because some neutrons are absorbed in the burnable poison and they are prevented from entering the fuel kernel. At the end of life, when the absorber is almost depleted, ore eutrons stream into the fuel kernel of QUADRISO particles causing fission reactions. The mechanism has been applied to a prismatic High Temperature Reactor with europium or erbium burnable absorbers, showing a significant reduction in the initial excess reactivity of the core.

  2. A feasibility study for the application of enriched gadolinia burnable absorber rods in nuclear core design

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chung Chan; Zee, Sung Quun; Kim, Kang Seog; Song, Jae Seung

    2000-12-01

    An analysis model using MICBURN-3/CASMO-3 is established for the enriched gadolinia burnable absorber rods. A homogenized cross section editing code, PROLOG, is modified so that it can handle such a fuel assembly that includes two different types of gadolinia rods. Study shows that Gd-155 and Gd-157 are almost same in suppressing the excess reactivity and it is recommended to enrich both odd number isotopes, Gd-155 and Gd-157. It is estimated that the cycle length increases by 2 days if enriched gadolinia rods are used in the commercial nuclear power plant such as YGN-3 of which the cycle length is assumed 2 years. For the advanced integral reactor SMART in which ultra long cycle length and soluble boron-free operation concept is applied, natural gadolinia burnable absorber rods fail to control the excess reactivity. On the other hand, enriched gadolinia rods are successful in controling the excess reactivity. To minimize power peakings, various placements of gadolinia rods are tested. Also initial reactivity holddown and gadolinia burnout time are parametrized with respect to the number of gadolinia rods and gadolinia weight fractions.

  3. IRRADIATION TESTING OF THE RERTR FUEL MINIPLATES WITH BURNABLE ABSORBERS IN THE ADVANCED TEST REACTOR

    Energy Technology Data Exchange (ETDEWEB)

    I. Glagolenko; D. Wachs; N. Woolstenhulme; G. Chang; B. Rabin; C. Clark; T. Wiencek

    2010-10-01

    Based on the results of the reactor physics assessment, conversion of the Advanced Test Reactor (ATR) at the Idaho National Laboratory (INL) can be potentially accomplished in two ways, by either using U-10Mo monolithic or U-7Mo dispersion type plates in the ATR fuel element. Both designs, however, would require incorporation of the burnable absorber in several plates of the fuel element to compensate for the excess reactivity and to flatten the radial power profile. Several different types of burnable absorbers were considered initially, but only borated compounds, such as B4C, ZrB2 and Al-B alloys, were selected for testing primarily due to the length of the ATR fuel cycle and fuel manufacturing constraints. To assess and compare irradiation performance of the U-Mo fuels with different burnable absorbers we have designed and manufactured 28 RERTR miniplates (20 fueled and 8 non-fueled) containing fore-mentioned borated compounds. These miniplates will be tested in the ATR as part of the RERTR-13 experiment, which is described in this paper. Detailed plate design, compositions and irradiations conditions are discussed.

  4. A reduced-boron OPR1000 core based on the BigT burnable absorber

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Hwan Yeal; Yahya, Mohd-Syukri; Kim, Yong Hee [Dept. of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon (Korea, Republic of)

    2016-04-15

    Reducing critical boron concentration in a commercial pressurized water reactor core offers many advantages in view of safety and economics. This paper presents a preliminary investigation of a reduced-boron pressurized water reactor core to achieve a clearly negative moderator temperature coefficient at hot zero power using the newly-proposed 'Burnable absorber-Integrated Guide Thimble' (BigT) absorbers. The reference core is based on a commercial OPR1000 equilibrium configuration. The reduced-boron ORP1000 configuration was determined by simply replacing commercial gadolinia-based burnable absorbers with the optimized BigT-loaded design. The equilibrium cores in this study were directly searched via repetitive Monte Carlo depletion calculations until convergence. The results demonstrate that, with the same fuel management scheme as in the reference core, application of the BigT absorbers can effectively reduce the critical boron concentration at the beginning of cycle by about 65 ppm. More crucially, the analyses indicate promising potential of the reduced-boron OPR1000 core with the BigT absorbers, as its moderator temperature coefficient at the beginning of cycle is clearly more negative and all other vital neutronic parameters are within practical safety limits. All simulations were completed using the Monte Carlo Serpent code with the ENDF/B-VII.0 library.

  5. ATR LEU Monolithic Foil-Type Fuel with Integral Cladding Burnable Absorber – Neutronics Performance Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Gray Chang

    2012-03-01

    The Advanced Test Reactor (ATR), currently operating in the United States, is used for material testing at very high neutron fluxes. Powered with highly enriched uranium (HEU), the ATR has a maximum thermal power rating of 250 MWth. Because of the large test volumes located in high flux areas, the ATR is an ideal candidate for assessing the feasibility of converting HEU driven reactor cores to low-enriched uranium (LEU) cores. The burnable absorber - 10B, was added in the inner and outer plates to reduce the initial excess reactivity, and to improve the peak ratio of the inner/outer heat flux. The present work investigates the LEU Monolithic foil-type fuel with 10B Integral Cladding Burnable Absorber (ICBA) design and evaluates the subsequent neutronics operating effects of this proposed fuel designs. The proposed LEU fuel specification in this work is directly related to both the RERTR LEU Development Program and the Advanced Test Reactor (ATR) LEU Conversion Project at Idaho National Laboratory (INL).

  6. Preliminary Nuclear Analysis for the HANARO Fuel Element with Burnable Absorber

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Chul Gyo; Kim, So Young; In, Won Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    Burnable absorber is used for reducing reactivity swing and power peaking in high performance research reactors. Development of the HANARO fuel element with burnable absorber was started in the U-Mo fuel development program at HANARO, but detailed full core analysis was not performed because the current HANARO fuel management system is uncertain to analysis the HANARO core with burnable absorber. A sophisticated reactor physics system is required to analysis the core. The McCARD code was selected and the detailed McCARD core models, in which the basic HANARO core model was developed by one of the McCARD developers, are used in this study. The development of nuclear fuel requires a long time and correct developing direction especially by the nuclear analysis. This paper presents a preliminary nuclear analysis to promote the fuel development. Based on the developed fuel, the further nuclear analysis will improve reactor performance and safety. Basic nuclear analysis for the HANARO and the AHR were performed for getting the proper fuel elements with burnable absorber. Addition of 0.3 - 0.4% Cd to the fuel meat is promising for the current HANARO fuel element. Small addition of burnable absorber may not change any fuel characteristics of the HANARO fuel element, but various basic tests and irradiation tests at the HANARO core are required.

  7. A study on the nuclear characteristics of enriched gadolinia burnable absorber rods; the final report

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chung Chan; Zee, Quun; Song, J. S.; Cho, B. O.; Joo, H. G.; Park, S. Y.; Kim, H. Y.; Cho, J. Y.; Kim, K. S

    2001-12-01

    An analysis model using MICBURN-3/CASMO-3 is established for the enriched gadolinia burnable absorber rods. A homogenized cross section editing code, PROLOG, is modified so that it can handle such a fuel assembly that includes two different types of gadolinia rods. Study shows that Gd-155 and Gd-157 are almost same characteristics in suppressing the excess reactivity and it is recommended to enrich both odd number isotopes, Gd-155 and Gd-157. To minimize power peakings, various placements of gadolinia rods are tested. Also initial reactivity holddown and gadolinia burnout time are parametrized with respect to the number of gadolinia rods and gadolinia weight fractions. Cycle length increases by 8 days if enriched gadolinia rods are used in the commercial nuclear power plant such as YGN-3 with 2 year-cycle-length. The nuclear characteristics such as soluble boron concentrations and power distributions are almost same. The maximum power of the gadolinia rods are slightly increased but gadolinia contents are reduced. For SMART with ultra longer cycle length and soluble boron-free operation concept cycle length can be extended by maximum 90 days due to increased fuel loading.

  8. Microstructural Characterization of Burnable Absorber Materials Being Evaluated for Application in LEU U-Mo Fuel Plates

    Energy Technology Data Exchange (ETDEWEB)

    J. F. Jue; B. Miller; B. Yao; E. Perez; Y. H. Sohn

    2011-03-01

    The starting microstructure of a fuel plate will impact how it performs during irradiation. As a result, microstructural characterization has been performed on as-fabricated monolithic fuel plates to determine the changes in fuel plate microstructure that may result from changes in fabrication parameters. Particular focus has been given to the fuel plate U-10Mo/Zr and Zr/AA6061 cladding interfaces, since the integrity of these interfaces will play a big role in determining the overall performance of the fuel plate during irradiation. In addition, burnable absorber materials for potential incorporation into monolithic fuel plates have been characterized to identify their as-fabricated microstructures. This information will be important when trying to understand the PIE data from fuel plates with burnable absorbers that are irradiated in future irradiation experiments. This paper will focus on the microstructures observed using optical metallography, X-ray diffraction, and scanning and transmission electron microscopy for monolithic fuel plates exposed to different fabrication parameters and for as-fabricated burnable absorber materials.

  9. Incorporation of Integral Fuel Burnable Absorbers Boron and Gadolinium into Zirconium-Alloy Fuel Clad Material

    Energy Technology Data Exchange (ETDEWEB)

    Sridharan, K.; Renk, T.J.; Lahoda, E.J.; Corradini, M.L

    2004-12-14

    Long-lived fuels require the use of higher enrichments of 235U or other fissile materials. Such high levels of fissile material lead to excessive fuel activity at the beginning of life. To counteract this excessive activity, integral fuel burnable absorbers (IFBA) are added to some rods in the fuel assembly. The two commonly used IFBA elements are gadolinium, which is added as gadolinium-oxide to the UO2 powder, and boron, which is applied as a zirconium-diboride coating on the UO2 pellets using plasma spraying or chemical vapor deposition techniques. The incorporation of IFBA into the fuel has to be performed in a nuclear-regulated facility that is physically separated from the main plant. These operations tend to be very costly because of their small volume and can add from 20 to 30% to the manufacturing cost of the fuel. Other manufacturing issues that impact cost and performance are maintaining the correct levels of dosing, the reduction in fuel melting point due to gadolinium-oxide additions, and parasitic neutron absorption at fuel's end-of-life. The goal of the proposed research is to develop an alternative approach that involves incorporation of boron or gadolinium into the outer surface of the fuel cladding material rather than as an additive to the fuel pellets. This paradigm shift will allow for the introduction of the IFBA in a non-nuclear regulated environment and will obviate the necessity of additional handling and processing of the fuel pellets. This could represent significant cost savings and potentially lead to greater reproducibility and control of the burnable fuel in the early stages of the reactor operation. The surface alloying is being performed using the IBEST (Ion Beam Surface Treatment) process developed at Sandia National Laboratories. IBEST involves the delivery of energetic ion beam pulses onto the surface of a material, near-surface melting, and rapid solidification. The non-equilibrium nature of such processing allows for

  10. A study on the nuclear characteristics of enriched gadolinia burnable absorber rods; the first year (2000) report

    Energy Technology Data Exchange (ETDEWEB)

    Zee, Sung Quun; Lee, C.C.; Song, J. S.; Cho, B. O.; Joo, H. G.; Park, S. Y.; Kim, H. Y.; Cho, J. Y.; Kim, K. S

    2001-04-01

    An analysis model using MICBURN-3/CASMO-3 is established for the enriched gadolinia burnable absorber rods. A homogenized cross section editing code, PROLOG, is modified so that it can handle such a fuel assembly that includes two different types of gadolinia rods. Study shows that Gd-155 and Gd-157 are almost same in suppressing the excess reactivity and it is recommended to enrich both odd number isotopes, Gd-155 and Gd-157. It is estimated that the cycle length increases by 2 days if enriched gadolinia rods are used in the commercial nuclear power plant such as YGN-3 of which the cycle length is assumed 2 years. For the advanced integral reactor SMART in which ultra long cycle length and soluble boron-free operation concept is applied, natural gadolinia burnable absorber rods fail to control the excess reactivity. On the other hand, enriched gadolinia rods are successful in controling the excess reactivity. To minimize power peakings, various placements of gadolinia rods are tested. Also initial reactivity holddown and gadolinia burnout time are parametrized with respect to the number of gadolinia rods and gadolinia weight fractions.

  11. Reactor physics analysis for the design of nuclear fuel lattices with burnable poisons

    Energy Technology Data Exchange (ETDEWEB)

    Espinosa-Paredes, G. [Area de Ingenieria en Recursos Energeticos, Universidad Autonoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, 09340 Mexico, D.F. (Mexico); Guzman, Juan R., E-mail: maestro_juan_rafael@hotmail.com [Departamento de Fisica y Matematicas, Instituto Politecnico Nacional, Adolfo Lopez Mateos, San Pedro Zacatenco, 07738 Mexico, D.F. (Mexico)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer A fuel rod optimization for the coupled bundle-core design in a BWR is developed. Black-Right-Pointing-Pointer An algorithm to minimize the rod power peaking factor is used. Black-Right-Pointing-Pointer The fissile content is divided in two factors. Black-Right-Pointing-Pointer A reactor physics analysis of these factors is performed. Black-Right-Pointing-Pointer The algorithm is applied to a typical BWR fuel lattice. - Abstract: The main goals in nuclear fuel lattice design are: (1) minimizing the rod power peaking factor (PPF) in order that the power level distribution is the most uniform; (2) obtaining a prescribed target value for the multiplication factor (k) at the end of the irradiation in order that the fuel lattice reaches the desired reactivity; and (3) obtaining a prescribed target value for the k at the beginning of the irradiation in order that the reactivity excess is neither a high value (to ease the maneuvering of the control systems) nor a low value (to avoid the penalization of the high cost of the burnable poison content). In this work a simple algorithm to design the burnable poison bearing nuclear fuel lattice is presented. This algorithm is based on a reactor physics analysis. The algorithm is focused on finding the radial distribution of the fuel rods having different fissile and burnable poison contents in order to obtain: (1) an adequate minimum PPF; (2) a prescribed target value of the k at the end of the irradiation; and (3) a prescribed target value of the k at the beginning of the irradiation. This algorithm is based on the factorization of the fissile and burnable poison contents of each fuel rod and on the application of the first-order perturbation theory. The performance of the algorithm is demonstrated with the design of a fuel lattice composed of uranium dioxide (UO{sub 2}) and gadolinium dioxide (Gd{sub 2}O{sub 3}) for boiling water reactors (BWR). This algorithm has been accomplished

  12. Nodal Diffusion Burnable Poison Treatment for Prismatic Reactor Cores

    Energy Technology Data Exchange (ETDEWEB)

    A. M. Ougouag; R. M. Ferrer

    2010-10-01

    The prismatic block version of the High Temperature Reactor (HTR) considered as a candidate Very High Temperature Reactor (VHTR)design may use burnable poison pins in locations at some corners of the fuel blocks (i.e., assembly equivalent structures). The presence of any highly absorbing materials, such as these burnable poisons, within fuel blocks for hexagonal geometry, graphite-moderated High Temperature Reactors (HTRs) causes a local inter-block flux depression that most nodal diffusion-based method have failed to properly model or otherwise represent. The location of these burnable poisons near vertices results in an asymmetry in the morphology of the assemblies (or blocks). Hence the resulting inadequacy of traditional homogenization methods, as these “spread” the actually local effect of the burnable poisons throughout the assembly. Furthermore, the actual effect of the burnable poison is primarily local with influence in its immediate vicinity, which happens to include a small region within the same assembly as well as similar regions in the adjacent assemblies. Traditional homogenization methods miss this artifact entirely. This paper presents a novel method for treating the local effect of the burnable poison explicitly in the context of a modern nodal method.

  13. Evaluation of the presence of a burnable absorber in an assembly 3x3 type PWR; Evaluacion de la presencia de un absorbedor quemable en un ensamble 3x3 tipo PWR

    Energy Technology Data Exchange (ETDEWEB)

    Martinez F, M. A.; Del Valle G, E.; Alonso V, G. [IPN, Escuela Superior de Fisica y Matematicas, Av. IPN s/n, Col. Lindavista, Mexico D. F. 07738 (Mexico)]. e-mail: mike_ipn_esfm@hotmail.com

    2008-07-01

    In the present work the effect is evaluated that causes the presence of a burnable absorber in an adjustment of rods of 3x3 of a fuel assembly type PWR using CASMO-4 code, when comparing the infinite multiplication factor and some average cross sections by means of codes MCNP-4A, CASMO-3 and HELIOS. For this evaluation two cases are evaluated: first consists of an adjustment of rods of 3x3 full completely of fuel and the second consists of a central rod full with a burnable absorber type wet annular burnable absorber (WABA) and the remaining full fuel rods. In both cases the enrichment of the fissile isotopes is varied, for two types of fuel, MOX degree armament and UO{sub 2}. (Author)

  14. A study on the oxidation characteristic of UO{sub 2}-Gd{sub 2}O{sub 3} pellet for recycling of burnable absorber pellet scrap

    Energy Technology Data Exchange (ETDEWEB)

    Kim, K. S.; Song, K. W.; Kang, K. W.; Yang, J. H.; Kim, J. H

    2001-04-01

    The development of recycling process of defective (U,Gd)O{sub 2} scrap is one of the important subject in this project. Among the several burnable absorbers, Gd has a very large neutron absorption cross-section. Therefore, gadolinia bearing UO{sub 2} fuel, (U,Gd)O{sub 2}, has been widely used as a burnable absorber in light water reactors. During the pellet fabrication process, fairly amount of defective (U,Gd)O{sub 2} pellets are produced and it is necessary to recycle the scraps. Generally, the defective scraps are powdered through the oxidation in air in the temperature range of 450 to 550 deg C and then mixed with co-milled powder, and further processed to fabricate (U,Gd)O{sub 2} pellets. In addition, the sintered pellet properties are closely depend on the powder property of oxidized M{sub 3}O{sub 8} powder. Therefore, the careful investigate of oxidation kinetics and related powder property of (U,Gd)O{sub 2} is very important. The oxidation behavior of UO{sub 2}-6wt% Gd{sub 2}O{sub 3} and UO{sub 2}-12wt% Gd{sub 2}O{sub 3} has been studied in the temperature range from 350 to 700 deg C using TGA and XRD techniques in air. UO{sub 2} was necessarily oxidized to U{sub 3}O{sub 8} regardless of oxidation temperature and its weight gain was 4wt%. However, (U,Gd)O{sub 2} exhibit a different oxidation behavior ; The final phase and saturated weight gain depends on oxidation temperature. The saturated weight gain increases with oxidation temperature up to 500deg C and thereafter decreases with temperature. In addition, the amount of weight gain obtained at 500 deg C was smaller in UO{sub 2}-12wt% Gd{sub 2}O{sub 3} than in UO{sub 2}-6wt% Gd{sub 2}O{sub 3} and the final phase at the saturated weight gain was M{sub 3}O{sub 8} in UO{sub 2}-6wt% Gd{sub 2}O{sub 3} but the mixture of M{sub 4}O{sub 9} and M{sub 3}O{sub 8} in UO{sub 2}-12wt% Gd{sub 2}O{sub 3}. It is supposed that Gd substitution for U decreases the equilibrium O/M ratio and thereby enhance the stability of M

  15. A Preliminary Study on the Conceptual Design of Thorium/Uranium Mixed Nuclear Fuel for the Alternative of Burnable Poison in Commercial Pressurized Water Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Hwan; Kim, Song Hyun; Kim, Jong Kyung [Hanyang Univ., Seoul (Korea, Republic of)

    2013-10-15

    Thorium has higher neutron absorption cross section than that of U-238. Thus, the thorium mixed uranium oxide nuclear fuel can reduce the initial excessive reactivity and the long-live radio-wastes with increasing the fuel utilization efficiency. In this study, a preliminary study on the application of the thorium/uranium mixed fuel is performed for the alternative of the PLUS7 fuel assembly which includes burnable poison. A conceptual design without geometrical change is proposed and the reactor characteristics are analyzed. In this study, a fuel assembly using the uranium/thorium mixed fuel was designed to substitute the assembly which includes burnable poison. The reactor characteristics, which are k{sub inf}, power distribution and plutonium production rate, were evaluated and the results are compared with the E1 assembly which is used in the OPR1000 reactor. The results show that the proposed design can efficiently reduce the excessive reactivity, peak power, and plutonium production with increasing the fuel utilization period.

  16. Design and application of functional absorbers

    Institute of Scientific and Technical Information of China (English)

    WANG Jiqing

    2004-01-01

    This paper gives an overview of the research at Institute of Acoustics, Tongji University, on functional absorbers and experience acquired in practical applications over the past three decades. Experiments and analysis of the absorption characteristics of three different geometrical forms of functional absorbers, i.e., panels, cubes and tubes, were conducted with different arrangements. The resulting esthetical effects are illustrated with pictures. Several non-fiber materials are used to compose functional absorbers with advantages both in acoustic properties and in architectural features. Cost effectiveness analysis is also given in order to provide design guidelines.

  17. Development of Improved Burnable Poisons for Commercial Nuclear Power Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Renier, J.A.

    2002-04-17

    Burnable poisons are used in all modern nuclear reactors to permit higher loading of fuel without the necessity of an overly large control rod system. This not only permits a longer core life but can also be used to level the power distribution. Commercial nuclear reactors commonly use B{sub 4}C in separate non-fueled rods and more recently, zirconium boride coatings on the fuel pellets or gadolinium oxide mixed with the fuel. Although the advantages are great, there are problems with using these materials. Boron, which is an effective neutron absorber, transmutes to lithium and helium upon absorption of a neutron. Helium is insoluble and is eventually released to the interior of the fuel rod, where it produces an internal pressure. When sufficiently high, this pressure stress could cause separation of the cladding from the fuel, causing overly high centerline temperatures. Gadolinium has several very strongly absorbing isotopes, but not all have large cross sections and result in residual burnable poison reactivity worth at the end of the fuel life. Even if the amount of this residual absorber is small and the penalty in operation small, the cost of this penalty, even if only several days, can be very high. The objective of this investigation was to study the performance of single isotopes in order to reduce the residual negative reactivity left over at the end of the fuel cycle. Since the behavior of burnable poisons can be strongly influenced by their configuration, four forms for the absorbers were studied: homogeneously mixed with the fuel, mixed with only the outer one-third of the fuel pellet, coated on the perimeter of the fuel pellets, and alloyed with the cladding. In addition, the numbers of fuel rods containing burnable poison were chosen as 8, 16, 64, and 104. Other configurations were chosen for a few special cases. An enrichment of 4.5 wt% {sup 235}U was chosen for most cases for study in order to achieve a 4-year fuel cycle. A standard pressurized

  18. Development of a highly efficient burnable poison matrix material for cycle lifetime extension

    Energy Technology Data Exchange (ETDEWEB)

    Tulenko, J.S. [Florida Univ., 202 Nuclear Science Center, Gainesville, FL (United States); Baney, R.H.; Pressley, L. [Florida Univ., Gainesville, FL (United States)

    2001-07-01

    The University of Florida (UF) is carrying out basic research on a new class of thermally stable boron containing materials that from early indications appear to have special properties that will greatly enhance the performance of Burnable Poison Rod Assemblies (BPRA(tm)s) and address one of the major disadvantages of the use of boron shims. The new class of polymer materials, poly-acetylenic carbonyl-siloxane, termed ''Carborane'', were developed by Dr. T. Keller of the Naval Research Laboratory (NRL). Dr. T. Keller is cooperating in this research effort. Other classes of boron containing polymer materials are also under review. Displacement of water by the boron shims incurs an ''end of cycle reactivity penalty'' since at the end of cycle the moderator coefficient is strongly negative. ''Carborane'' has the property of being able to contain a tailored amount of boron while maintaining an extremely high hydrogen content, and at the same time being extremely stable to high temperatures and to neutron irradiation. Tests run by the NRL have shown that ''Carborane'' is stable to about 1000 C. The high hydrogen and carbon content contained in the ''Carborane'' Polymer offsets the large fuel cycle reactivity penalty which occurs with current generation BPRA(tm)s, as a result of the reactivity loss resulting from the BPRA(tm)s displacement of moderator water in the guide tubes of Pressurized Water Reactor (PWR) assemblies. Current generation BPRA utilize B{sub 4}C in an Al{sub 2}O{sub 3} matrix. In an attempt to minimize the reactivity penalty from water displacement, Westinghouse has developed a costly annular BPRA, called the Wet Annular Burnable Absorber (WABA) assembly. This burnable poison rod design reduces the moderator displacement by 22% by the use of a central annular water hole. The ''Carborane'' matrix proposed by the University of Florida

  19. Tracking Performances of Several Front-Absorber Designs

    CERN Document Server

    Lautridou, P; CERN. Geneva; Métivier, V; Rahmani, A; Ramillien, V; Reposeur, T; Morsch, Andreas; Cussonneau, J P

    1998-01-01

    The tracking performances of the ALICE forward muon spectrometer are investigated for several front-absorbers designs. The obtained mass resolution is compared to the one of the absorber proposed in the LOI. Out of punchthrough considerations, two absorbers compositions, including a Carbon+Concrete sandwich design, allow to reach the requested mass resolution for the Y's. Almost identical behaviours are observed versus rapidity and transverse momentum of resonances for both new candidates. These proposed designs improve the mass resolution performances and could stand as suitable absorber options for the forward muon spectrometer of ALICE. The Carbon+Concrete absorber has been retained for the Technical Proposal [1].

  20. Nano-Composite Superfine Nickel Powder Double Absorbent Coating Designing

    Institute of Scientific and Technical Information of China (English)

    LU Yan-hong; WANG Zhi-hui; HUANG Dong-zhen; HU Chuan-xin; ZHANG Chen-jia; LI Wan-zhi; LIANG Wen-ting

    2004-01-01

    We adopt a definite procedure to compound traditional absorbing material-superfine powder nickel and nano -SiC powder to obtain the nano-composite nickel powder, then testing the absorbing speciality of the composite powder. In virtue of computer assistant designing, we apply double-deck absorbent structure to improve absorbent effect and widen wave band. The experiment indicated that it is possible to achieve the anticipative object to improve the absorbing capability by adopting nano-composite absorbing material, but each component of the composite material must have matched electromagnetic parameter with another. For matching double-coating structure, it ought to modulate the correlativity of each factor to achieve the most matching in order to optimise the absorbent speciality.

  1. Optimal active vibration absorber - Design and experimental results

    Science.gov (United States)

    Lee-Glauser, Gina; Juang, Jer-Nan; Sulla, Jeffrey L.

    1993-01-01

    An optimal active vibration absorber can provide guaranteed closed-loop stability and control for large flexible space structures with collocated sensors/actuators. The active vibration absorber is a second-order dynamic system which is designed to suppress any unwanted structural vibration. This can be designed with minimum knowledge of the controlled system. Two methods for optimizing the active vibration absorber parameters are illustrated: minimum resonant amplitude and frequency matched active controllers. The Controls-Structures Interaction Phase-1 Evolutionary Model at NASA LaRC is used to demonstrate the effectiveness of the active vibration absorber for vibration suppression. Performance is compared numerically and experimentally using acceleration feedback.

  2. Optimal active vibration absorber: Design and experimental results

    Science.gov (United States)

    Lee-Glauser, Gina; Juang, Jer-Nan; Sulla, Jeffrey L.

    1992-01-01

    An optimal active vibration absorber can provide guaranteed closed-loop stability and control for large flexible space structures with collocated sensors/actuators. The active vibration absorber is a second-order dynamic system which is designed to suppress any unwanted structural vibration. This can be designed with minimum knowledge of the controlled system. Two methods for optimizing the active vibration absorber parameters are illustrated: minimum resonant amplitude and frequency matched active controllers. The Controls-Structures Interaction Phase-1 Evolutionary Model at NASA LaRC is used to demonstrate the effectiveness of the active vibration absorber for vibration suppression. Performance is compared numerically and experimentally using acceleration feedback.

  3. Parametric Study of the Effect of Burnable Poison Rods for PWR Burnup Credit

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, J.C.

    2001-09-28

    The Interim Staff Guidance on burnup credit (ISG-8) issued by the United States Nuclear Regulatory Commission's (U.S. NRC) Spent Fuel Project Office recommends restricting the use of burnup credit to assemblies that have not used burnable absorbers. This recommended restriction eliminates a large portion of the currently discharged spent fuel assemblies from cask loading, and thus severely limits the practical usefulness of burnup credit. In the absence of readily available information on burnable poison rod (BPR) design specifications and usage in U.S. pressurized-water-reactors (PWRs), and the subsequent reactivity effect of BPR exposure on discharged spent nuclear fuel (SNF), NRC staff has indicated a need for additional information in these areas. In response, this report presents a parametric study of the effect of BPR exposure on the reactivity of SNF for various BPR designs, fuel enrichments, and exposure conditions, and documents BPR design specifications. Trends in the reactivity effects of BPRs are established with infinite pin-cell and assembly array calculations with the SCALE and HELIOS code packages, respectively. Subsequently, the reactivity effects of BPRs for typical initial enrichment and burnup combinations are quantified based on three-dimensional (3-D) KENO V.a Monte Carlo calculations with a realistic rail-type cask designed for burnup credit. The calculations demonstrate that the positive reactivity effect due to BPR exposure increases nearly linearly with burnup and is dependent on the number, poison loading, and design of the BPRs and the initial fuel enrichment. Expected typical reactivity increases, based on one-cycle BPR exposure, were found to be less than 1% {Delta}k. Based on the presented analysis, guidance is offered on an appropriate approach for calculating bounding SNF isotopic data for assemblies exposed to BPRs. Although the analyses do not address the issue of validation of depletion methods for assembly designs with BPRs

  4. Design of integration-ready metasurface-based infrared absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Ogando, Karim, E-mail: karim@cab.cnea.gov.ar; Pastoriza, Hernán [Laboratorio de Bajas Temperaturas, Instituto Balseiro and Centro Atómico Bariloche, Bariloche 8400 (Argentina)

    2015-07-28

    We introduce an integration ready design of metamaterial infrared absorber, highly compatible with many kinds of fabrication processes. We present the results of an exhaustive experimental characterization, including an analysis of the effects of single meta-atom geometrical parameters and collective arrangement. We confront the results with the theoretical interpretations proposed in the literature. Based on the results, we develop a set of practical design rules for metamaterial absorbers in the infrared region.

  5. 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...... in the working range. We demonstrate the possibility of the absorber bandwidth control with the metamaterial’s unit cell geometry. The results of fabrication and characterization of the THz graphene metamaterials based absorbers will be presented at the conference....

  6. Thin Perfect Absorbers for Electromagnetic Waves: Theory, Design, and Realizations

    Science.gov (United States)

    Ra'di, Y.; Simovski, C. R.; Tretyakov, S. A.

    2015-03-01

    With recent advances in nanophotonics and nanofabrication, considerable progress has been achieved in realizations of thin composite layers designed for full absorption of incident electromagnetic radiation, from microwaves to the visible. If the layer is structured at a subwavelength scale, thin perfect absorbers are usually called "metamaterial absorbers," because these composite structures are designed to emulate some material responses not reachable with any natural material. On the other hand, many thin absorbing composite layers were designed and used already in the time of the introduction of radar technology, predominantly as a means to reduce radar visibility of targets. In view of a wide variety of classical and new topologies of optically thin metamaterial absorbers and plurality of applications, there is a need for a general, conceptual overview of the fundamental mechanisms of full absorption of light or microwave radiation in thin layers. Here, we present such an overview in the form of a general theory of thin perfectly absorbing layers. Possible topologies of perfect metamaterial absorbers are classified based on their fundamental operational principles. For each of the identified classes, we provide design equations and give examples of particular realizations. The concluding section provides a summary and gives an outlook on future developments in this field.

  7. Ultrathin planar broadband absorber through effective medium design

    Institute of Scientific and Technical Information of China (English)

    Dong Liu; Haitong Yu; Zhen Yang; Yuanyuan Duan

    2016-01-01

    Ultrathin planar absorbers hold promise in solar energy systems because they can reduce the material,fabrication,and system cost.Here,we present a general strategy of effective medium design to realize ultrathin planar broadband absorbers.The absorber consists of two ultrathin absorbing dielectrics to designan effective absorbing medium,a transparent layer,and metallic substrate.Compared with previous studies,this strategy provides another dimension of freedom to enhance optical absorption;therefore,destructive interference can be realized over a broad spectrum.To demonstrate the power and simplicity of this strategy,we both experimentally and theoretically characterized an absorber with 5-nm-thick Ge,10-nm-thick Ti,and 50-nm-thick SiO2 films coated on an Ag substrate fabricated using simple deposition methods.Absorptivity higher than 80% was achieved in 15-nm-thick (1/50 of the center wavelength) Ge and Ti films from 400 nm to near 1 μm.As an application example,we experimentally demonstrated that the absorber exhibited a normal solar absorptivity of 0.8 with a normal emittance of 0.1 at 500 ℃,thus demonstrating its potential in solar thermal systems.The effective medium design strategy is general and allows material versatility,suggesting possible applications in real-time optical manipulation using dynamic materials.

  8. Design of electromagnetic shock absorbers for automotive suspensions

    Science.gov (United States)

    Amati, Nicola; Festini, Andrea; Tonoli, Andrea

    2011-12-01

    Electromechanical dampers seem to be a valid alternative to conventional shock absorbers for automotive suspensions. They are based on linear or rotative electric motors. If they are of the DC-brushless type, the shock absorber can be devised by shunting its electric terminals with a resistive load. The damping force can be modified by acting on the added resistance. To supply the required damping force without exceeding in size and weight, a mechanical or hydraulic system that amplifies the speed is required. This paper illustrates the modelling and design of such electromechanical shock absorbers. This paper is devoted to describe an integrated design procedure of the electrical and mechanical parameters with the objective of optimising the device performance. The application to a C class front suspension car has shown promising results in terms of size, weight and performance.

  9. DESIGN METHOD OF MAGNETORHEOLOGICAL FLUID SHOCK ABSORBER FOR CAR SUSPENSION

    Institute of Scientific and Technical Information of China (English)

    LIAO Changrong; ZHANG Honghui; YU Miao; CHEN Weimin

    2008-01-01

    The Bingham constitutive model, which is previously used in depiction of magnetorheological (MR) fluids rheological behaviors for design devices, exhibits discontinuous characteristics in representation of pre-yield behaviors and post-yield behaviors. A Biviscous constitutive model is presented to depict rheological behaviors of MR fluids and design automotive shock absorber. Quasi-static flow equations of MR fluids in annular channels are set theoretically up based on Navier-Stokes equations and several rational simplifications are made. And both flow boundary conditions and flow compatibilities conditions are established. Meantime, analytical velocity profiles of MR fluids though annular channels are obtained via solution of the quasi-static flow equations using Biviscous constitutive model. The prediction methodology of damping force offered by MR fluid shock absorber is formulated and damping performances are predicated in order to determine design parameters. MR fluid shock absorber for Mazda 323 car suspension is designed and fabricated in Chongqing University, China. Measurements from sinusoidal displacement cycle by Shanchuan Shock Absorber Ltd. of China North Industry Corporation reveal that the analytical methodology and design theory are reasonable.

  10. Absorbing Set Spectrum Approach for Practical Code Design

    CERN Document Server

    Wang, Jiadong; Zhang, Zhengya; Wesel, Richard

    2011-01-01

    This paper focuses on controlling the absorbing set spectrum for a class of regular LDPC codes known as separable, circulant-based (SCB) codes. For a specified circulant matrix, SCB codes all share a common mother matrix, examples of which are array-based LDPC codes and many common quasi-cyclic codes. SCB codes retain the standard properties of quasi-cyclic LDPC codes such as girth, code structure, and compatibility with efficient decoder implementations. In this paper, we define a cycle consistency matrix (CCM) for each absorbing set of interest in an SCB LDPC code. For an absorbing set to be present in an SCB LDPC code, the associated CCM must not be full columnrank. Our approach selects rows and columns from the SCB mother matrix to systematically eliminate dominant absorbing sets by forcing the associated CCMs to be full column-rank. We use the CCM approach to select rows from the SCB mother matrix to design SCB codes of column weight 5 that avoid all low-weight absorbing sets (4, 8), (5, 9), and (6, 8). ...

  11. Design and analysis of crossover trials for absorbing binary endpoints.

    Science.gov (United States)

    Nason, Martha; Follmann, Dean

    2010-09-01

    The crossover is a popular and efficient trial design used in the context of patient heterogeneity to assess the effect of treatments that act relatively quickly and whose benefit disappears with discontinuation. Each patient can serve as her own control as within-individual treatment and placebo responses are compared. Conventional wisdom is that these designs are not appropriate for absorbing binary endpoints, such as death or HIV infection. We explore the use of crossover designs in the context of these absorbing binary endpoints and show that they can be more efficient than the standard parallel group design when there is heterogeneity in individuals' risks. We also introduce a new two-period design where first period "survivors" are rerandomized for the second period. This design combines the crossover design with the parallel design and achieves some of the efficiency advantages of the crossover design while ensuring that the second period groups are comparable by randomization. We discuss the validity of the new designs and evaluate both a mixture model and a modified Mantel-Haenszel test for inference. The mixture model assumes no carryover or period effects while the Mantel-Haenszel approach conditions out period effects. Simulations are used to compare the different designs and an example is provided to explore practical issues in implementation.

  12. Reactivity and neutron flux measurements in IPEN/MB-01 reactor with B{sub 4}C burnable poison; Medidas de reatividade e de fluxo de neutrons no reator IPEN/MB-01 com veneno queimavel de B{sub 4}C

    Energy Technology Data Exchange (ETDEWEB)

    Fer, Nelson Custodio; Moreira, Joao Manoel Losada [Centro Tecnologico da Marinha em Sao Paulo (CTMSP), SP (Brazil)

    2000-07-01

    Burnable poison rods, made of B{sub 4}C- Al{sub 2} O{sub 3} pellets with 5.01 mg/cm{sup 3} {sup 10} B concentration, have been manufactured for a set of experiments in the IPEN/MB-01 zero-power reactor. Several core parameters which are affected by the burnable poisons rods have been measured. The principal results, for the situation in which the burnable poison rods are located near the absorber rods of a control rod, are they cause a 29% rod worth shadowing, a reduction of 39% in the local void coefficient of reactivity, a reduction of 4.8% in the isothermal temperature coefficient of reactivity, and a reduction of 9% in the thermal neutron flux in the region where the burnable poison rods are located. These experimental results will be used for the validation of burnable poison calculation methods in the CTMSP. (author)

  13. Design of Hybrid Dynamic Balancer and Vibration Absorber

    Directory of Open Access Journals (Sweden)

    Y. R. Wang

    2014-01-01

    Full Text Available This study proposed a novel hybrid dynamic balancer and vibration absorber that is cheaper than active dampers and more effective than passive dampers. The proposed damping system does not need to be altered structurally to deal with different damping targets. Rather, the proposed vibration absorber is capable of self-adjustment to the optimal damping location in order to achieve balance and, thereby, optimize damping effects. The proposed device includes a groove under the damping target with inertial mass hung from a coil spring beneath. This allows the device to bounce vertically or rotate in order to reduce vibrations in the main body. The coil spring vibration absorber can also slide along the groove in order to adjust its location continuously until the vibrations in the system are minimized and the main body is balanced. Experiments verify the efficacy of the proposed device in improving damping performance beyond what has been achieved using conventional devices. We also provide an explanation of the theoretical underpinnings of the design as well as the implications of these findings with regard to future developments.

  14. Parametric design of an electrorheological shock absorber with the mixed-mode

    Institute of Scientific and Technical Information of China (English)

    ZHENG Ling; DENG Zhaoxiang; LI Yinong

    2003-01-01

    A mathematical model based on an electrorheological (ER) shock absorber with the mixed-mode is presented. Its application to the parametric design of an electrorheological fluid shock absorber with the simulation calculation performed by program MATLAB demonstrates that the model can predict the behavior of ER shock absorbers satisfactorily, shorten the design period of an electrorheological shock absorber, and reduce the cost in the prototype manufacturing. The strength analysis based on a three-dimensional finite element model for the electrorheological shock absorber confirm that the structure design of the ER shock absorber is reasonable, and the stress distribution is uniform.

  15. Graphene metascreen for designing compact infrared absorbers with enhanced bandwidth

    KAUST Repository

    Chen, Pai-Yen

    2015-03-31

    We propose a compact, wideband terahertz and infrared absorber, comprising a patterned graphene sheet on a thin metal-backed dielectric slab. This graphene-based nanostructure can achieve a low or negative effective permeability, necessary for realizing the perfect absorption. The dual-reactive property found in both the plasmonic graphene sheet and the grounded highpermittivity slab introduces extra poles into the equivalent circuit model of the system, thereby resulting in a dual-band or broadband magnetic resonance that enhances the absorption bandwidth. More interestingly, the two-dimensional patterned graphene sheet significantly simplifies the design and fabrication processes for achieving resonant magnetic response, and allows the frequency-reconfigurable operation via electrostatic gating.

  16. Design and Implementation of a Regenerative Shock Absorber

    OpenAIRE

    Maravandi, Amir

    2015-01-01

    In this thesis, the development of a novel regenerative shock absorber sized for a passengercar suspension system is studied. In the first phase, DC and AC rotary machines along with charging circuits, to be used in the energy conversion stage of the proposed shock absorber are analyzed. In this analysis, the rotary damping coefficients provided by these systems are obtained following by experimental results.In the second phase, the development of a novel regenerative shock absorber in a proo...

  17. Design and realization of a magnetic-type absorber with a broadened operating frequency band

    Institute of Scientific and Technical Information of China (English)

    Zhou Yong-Jiang; Pang Yong-Qiang; Cheng Hai-Feng

    2013-01-01

    In this paper,we present an efficient method to obtain absorbers with broadened operating frequency bands.They are accomplished by using conventional magnetic absorbing materials (MAMs) in the forms of array and mesh structures,which are similar to those in the case of a frequency selective surface.The proposed approach is verified not only by simulations but also by experimental results under the normal incidence at microwave frequencies.Moreover,the wideband absorber is lighter than the conventional magnetic absorber.These results indicate that our proposed absorbing structures can be used for designing good electromagnetic absorbers.

  18. Performance of Different Experimental Absorber Designs in Absorption Heat Pump Cycle Technologies: A Review

    Directory of Open Access Journals (Sweden)

    Jonathan Ibarra-Bahena

    2014-02-01

    Full Text Available The absorber is a major component of absorption cycle systems, and its performance directly impacts the overall size and energy supplies of these devices. Absorption cooling and heating cycles have different absorber design requirements: in absorption cooling systems, the absorber works close to ambient temperature, therefore, the mass transfer is the most important phenomenon in order to reduce the generator size; on the other hand, in heat transformer absorption systems, is important to recover the heat delivered by exothermic reactions produced in the absorber. In this paper a review of the main experimental results of different absorber designs reported in absorption heat pump cycles is presented.

  19. A simple model for the design of vertical tube absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Patnaik, V.; Perez-Blanco, H. [Pennsylvania State Univ., University Park, PA (United States); Ryan, W.A. [Gas Research Inst., Chicago, IL (United States)

    1993-08-01

    The absorption of water vapor in aqueous solutions of lithium bromide is modelled for a falling-film, vertical-tube absorber. The model is based on the solution of three ordinary differential equations to calculate solution bulk and interface concentration and temperature distributions and the coolant temperature distribution. The heat and mass transfer coefficients employed in the equations are extracted from the literature. In this way, the model incorporates recent information on wavy-laminar flows. Under certain conditions, the solution exhibits instabilities in the entrance region of the absorber tube, which are corrected by the introduction of a dampening factor incorporating relevant thermophysical properties. The usefulness of the model for generating absorber performance charts is demonstrated.

  20. Design of Absorbing Wave Maker based on Digital Filters

    DEFF Research Database (Denmark)

    Christensen, Morten; Frigaard, Peter

    An absorbing wave maker operated by means of on-line signals from digital FIR filters is presented. Surface elevations are measured in two positions in front of the wave maker. The reflected wave train is seperated by the sum of the incident and reflected wave trains by means of digital filtering...... and subsequent superposition of the measured surface elevations. The motion of the wave paddle required to absorb reflected waves is determined and added to the original wave paddle control signal. Irregular wave tests involving test structures with different degrees of reflection show that excellent absorption...

  1. Practical design of a nonlinear tuned vibration absorber

    DEFF Research Database (Denmark)

    Grappasonni, C.; Habib, G.; Detroux, T.

    2014-01-01

    The aim of the paper is to develop a new nonlinear tuned vibration absorber (NLTVA) capable of mitigating the vibrations of nonlinear systems which are known to exhibit frequency-energy-dependent oscillations. A nonlinear generalization of Den Hartog's equal-peak method is proposed to ensure equal...

  2. A Design Outline for Floating Point Absorber Wave Energy Converters

    Directory of Open Access Journals (Sweden)

    Mohammed Faizal

    2014-04-01

    Full Text Available An overview of the most important development stages of floating point absorber wave energy converters is presented. At a given location, the wave energy resource has to be first assessed for varying seasons. The mechanisms used to convert wave energy to usable energy vary for different wave energy conversion systems. The power output of the generator will have variations due to varying incident waves. The wave structure-interaction leads to modifications in the incident waves; thus, the power output is also affected. The device has to be stable enough to prevent itself from capsizing. The point absorber will give optimum performance when the incident wave frequencies correspond to the natural frequency of the device. The methods for calculating natural frequencies for pitching and heaving systems are presented. Mooring systems maintain the point absorber at the desired location. Various mooring configurations as well as the most commonly used materials for mooring lines are discussed. An overview of scaled modelling is also presented.

  3. Design of wide bandwidth pyramidal microwave absorbers using ferrite composites with broad magnetic loss spectra

    Science.gov (United States)

    Park, Myung-Jun; Kim, Sung-Soo

    2016-09-01

    Wide bandwidth microwave absorbers with a pyramidal shape and a significantly reduced thickness can be designed using high lossy ferrite materials with broad magnetic loss spectra. The microwave absorbing properties of pyramidal cone absorbers are analyzed using the transmission line approximation, which provides the reflection loss as a function of the material parameters and absorber geometry. Three types of ferrite materials (NiZn spinel ferrite, Co2Z hexaferrite, and RuCoM hexaferrite) are used as the absorbent fillers in a rubber matrix. Among these, Co2Z ferrite is the most suitable material for wide bandwidth pyramidal absorbers, due to its broad magnetic loss spectrum in the GHz frequency range. The optimal geometry of the pyramidal absorber is also determined using the transmission line theory. With the reduced total height of the pyramidal absorber (approximately 60 mm), a wide bandwidth (1.5-18 GHz with respect to the -20 dB reflection loss) can be realized. The proposed absorbers have a thickness advantage over the classical pyramidal ohmic absorbers; thus, they are suitable for small and semi-anechoic chambers.

  4. Basic Problems in Design and Inverse Engineering Solution for Outer Characteristic of Vehicle Suspension Shock Absorbers

    Institute of Scientific and Technical Information of China (English)

    俞德孚; 陈庆东; 李文君

    2003-01-01

    Based on the theory and the practical experiences of linearity design of feasible design area and inverse solution of non-linear outer characteristic of suspension shock absorber, in accordance with non-linearity outer characteristic formed by open-up damping coefficient, full-open damping coefficient and smoothness to safety ratio of suspension shock absorber, a method and a research conclusion of the feasible design and inverse solution for the basic problems of designing and inverse solution of non-linear outer characteristic of suspension damping components are provided.

  5. Design of mid-infrared ultra-wideband metallic absorber based on circuit theory

    Science.gov (United States)

    Arik, Kamalodin; Abdollahramezani, Sajjad; Farajollahi, Saeed; Khavasi, Amin; Rejaei, Behzad

    2016-12-01

    An ultra-broadband absorber of light is proposed by using periodic array of ultra-thin metallic ribbons on top of a lossless quarter-wavelength dielectric spacer placed on a metallic reflector. We propose a fully analytical circuit model for the structure, and then the absorber is duly designed based on the impedance matching concept. As a result, normalized bandwidth of 99.5% is realized by the proposed absorbing structure in mid-infrared regime. Performing a numerical optimization algorithm, we could also reach to normalized bandwidth of 103%.

  6. Design of Matched Absorbing Layers for Surface Plasmon-Polaritons

    Directory of Open Access Journals (Sweden)

    Sergio de la Cruz

    2012-01-01

    Full Text Available We describe a procedure for designing metal-metal boundaries for the strong attenuation of surface plasmon-polaritons without the introduction of reflections or scattering effects. Solutions associated with different sets of matching materials are found. To illustrate the results and the consequences of adopting different solutions, we present calculations based on an integral equation formulation for the scattering problem and the use of a nonlocal impedance boundary condition.

  7. Rare earths as burnable poison for extended cycles control in electricity generation reactors; Etude des terres rares en tant que poison consommable pour le controle des cycles allonges pour les reacteurs electrogenes

    Energy Technology Data Exchange (ETDEWEB)

    Asou, M.

    1995-05-12

    The search of an optimization of the French electronuclear network operations leads to a necessary optimization of the core performances. All the economic studies performed by the utilities had shown that there is a real gain to minimize shut down periods for refueling. So, increasing the cycle length from 12 to 18 months will present a gain of shut down for a three years operation period. The theoretical burnable absorber will be a fuel admixed material bringing the required initial negative reactivity with a burn-up kinetic well suited to the fuel and allowing the lowest residual penalty as possible. The residual penalty us defined in this case by the non complete burn up of the poison, by the low of fissile material and by the accumulate of residual isotopes or nuclides. Because of the well known use of gadolinium as burnable absorber for BWR`s and PWR`s operations, the search for the best compromise to optimize all the above stress is pointed towards the rare earths. In the nuclides family, considering criteria such as cross sections, natural abundance and availability only five nuclides can play the role as burnable absorbers, namely: gadolinium, samarium, dysprosium, europium and erbium. The study presented here will show that only gadolinium and erbium will be considered to control the reactivity of the PWR`s. (author). 58 refs., 65 figs., 47 tabs.

  8. Robust Optimal Design of a Nonlinear Dynamic Vibration Absorber Combining Sensitivity Analysis

    Directory of Open Access Journals (Sweden)

    R.A. Borges

    2010-01-01

    Full Text Available Dynamic vibration absorbers are discrete devices developed in the beginning of the last century used to attenuate the vibrations of different engineering structures. They have been used in several engineering applications, such as ships, power lines, aeronautic structures, civil engineering constructions subjected to seismic induced excitations, compressor systems, etc. However, in the context of nonlinear dynamics, few works have been proposed regarding the robust optimal design of nonlinear dynamic vibration absorbers. In this paper, a robust optimization strategy combined with sensitivity analysis of systems incorporating nonlinear dynamic vibration absorbers is proposed. Although sensitivity analysis is a well known numerical technique, the main contribution intended for this study is its extension to nonlinear systems. Due to the numerical procedure used to solve the nonlinear equations, the sensitivities addressed herein are computed from the first-order finite-difference approximations. With the aim of increasing the efficiency of the nonlinear dynamic absorber into a frequency band of interest, and to augment the robustness of the optimal design, a robust optimization strategy combined with the previous sensitivities is addressed. After presenting the underlying theoretical foundations, the proposed robust design methodology is performed for a two degree-of-freedom system incorporating a nonlinear dynamic vibration absorber. Based on the obtained results, the usefulness of the proposed methodology is highlighted.

  9. MICE -- Absorber and focus coil safety working group design document: Preliminary design and assessments

    Energy Technology Data Exchange (ETDEWEB)

    Barr, Giles; Baynham, Elwyn; Black, Edgar; Bradshaw, Tom; Cummings, Mary Anne; Green, Michael A.; Ishimoto, Shigeru; Ivanyushenkov, Yury; Lau, Wing; Zisman, Michael

    2003-12-04

    A Neutrino Factory based on a muon storage ring is the ultimate tool for studies of neutrino oscillations, including possibly the discovery of leptonic CP violation. it is also the first step toward a muon collider. To develop a stored-muon-beam facility to serve as a Neutrino Factory, it is necessary to ''cool'' a muon beam (decrease its phase-space volume). The short lifetime of the muon, 2.2 {micro}s at rest, eliminates all currently demonstrated cooling techniques and requires that a new, heretofore untried, technique--ionization cooling--be employed. Although ionization cooling of muons has never been demonstrated in practice, it has been shown by end-to-end simulation and design studies to be an important factor both for the performance and for the cost of a Neutrino Factory. This motivates an international program of R and D, including an experimental demonstration at Rutherford Appleton Laboratory (RAL). The aims of the international Muon Ionization Cooling Experiment are: (1) to show that it is possible to design, engineer and build a section of cooling channel capable of giving the desired performance for a Neutrino Factory; and (2) to place it in a muon beam and measure its performance in various modes of operation and beam conditions, thereby investigating the limits and practicality of cooling. The MICE collaboration has designed an experiment in which a section of an ionization cooling channel is exposed to a muon beam. This cooling channel assembles liquid-hydrogen absorbers providing energy loss and high-gradient radio frequency (RF) cavities to re-accelerate the particles, all tightly contained in a magnetic channel. It reduces the beam transverse emittance by > 10% for muon momenta between 140 and 240 MeV/c. The layout of the experiment is shown. They utilize one complete magnetic cell of the cooling channel, comprising three absorber-focus-coil (AFC) modules and two RF-coupling-coil (RFCC) modules. Spectrometers placed before

  10. A new fast neutron collar for safeguards inspection measurements of fresh low enriched uranium fuel assemblies containing burnable poison rods

    Science.gov (United States)

    Evans, Louise G.; Swinhoe, Martyn T.; Menlove, Howard O.; Schwalbach, Peter; Baere, Paul De; Browne, Michael C.

    2013-11-01

    Safeguards inspection measurements must be performed in a timely manner in order to detect the diversion of significant quantities of nuclear material. A shorter measurement time can increase the number of items that a nuclear safeguards inspector can reliably measure during a period of access to a nuclear facility. In turn, this improves the reliability of the acquired statistical sample, which is used to inform decisions regarding compliance. Safeguards inspection measurements should also maintain independence from facility operator declarations. Existing neutron collars employ thermal neutron interrogation for safeguards inspection measurements of fresh fuel assemblies. A new fast neutron collar has been developed for safeguards inspection measurements of fresh low-enriched uranium (LEU) fuel assemblies containing gadolinia (Gd2O3) burnable poison rods. The Euratom Fast Collar (EFC) was designed with high neutron detection efficiency to make a fast (Cd) mode measurement viable whilst meeting the high counting precision and short assay time requirements of the Euratom safeguards inspectorate. A fast mode measurement reduces the instrument sensitivity to burnable poison rod content and therefore reduces the applied poison correction, consequently reducing the dependence on the operator declaration of the poison content within an assembly. The EFC non-destructive assay (NDA) of typical modern European pressurized water reactor (PWR) fresh fuel assembly designs have been simulated using Monte Carlo N-particle extended transport code (MCNPX) simulations. Simulations predict that the EFC can achieve 2% relative statistical uncertainty on the doubles neutron counting rate for a fast mode measurement in an assay time of 600 s (10 min) with the available 241AmLi (α,n) interrogation source strength of 5.7×104 s-1. Furthermore, the calibration range of the new collar has been extended to verify 235U content in variable PWR fuel designs in the presence of up to 32

  11. THE CALCULATION OF BURNABLE POISON CORRECTION FACTORS FOR PWR FRESH FUEL ACTIVE COLLAR MEASUREMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Croft, Stephen [Los Alamos National Laboratory; Favalli, Andrea [Los Alamos National Laboratory; Swinhoe, Martyn T. [Los Alamos National Laboratory

    2012-06-19

    Verification of commercial low enriched uranium light water reactor fuel takes place at the fuel fabrication facility as part of the overall international nuclear safeguards solution to the civilian use of nuclear technology. The fissile mass per unit length is determined nondestructively by active neutron coincidence counting using a neutron collar. A collar comprises four slabs of high density polyethylene that surround the assembly. Three of the slabs contain {sup 3}He filled proportional counters to detect time correlated fission neutrons induced by an AmLi source placed in the fourth slab. Historically, the response of a particular collar design to a particular fuel assembly type has been established by careful cross-calibration to experimental absolute calibrations. Traceability exists to sources and materials held at Los Alamos National Laboratory for over 35 years. This simple yet powerful approach has ensured consistency of application. Since the 1980's there has been a steady improvement in fuel performance. The trend has been to higher burn up. This requires the use of both higher initial enrichment and greater concentrations of burnable poisons. The original analytical relationships to correct for varying fuel composition are consequently being challenged because the experimental basis for them made use of fuels of lower enrichment and lower poison content than is in use today and is envisioned for use in the near term. Thus a reassessment of the correction factors is needed. Experimental reassessment is expensive and time consuming given the great variation between fuel assemblies in circulation. Fortunately current modeling methods enable relative response functions to be calculated with high accuracy. Hence modeling provides a more convenient and cost effective means to derive correction factors which are fit for purpose with confidence. In this work we use the Monte Carlo code MCNPX with neutron coincidence tallies to calculate the influence of

  12. Design of absorbency photometer used in a fully automatic ELISA analyzer

    Science.gov (United States)

    Dong, Ningning; Zhu, Lianqing; Dong, Mingli; Niu, Shouwei

    2008-03-01

    Absorbency measurement is the most important step in the ELISA analysis. Based on the spectrophotometry, absorbency photometer system used in a fully automatic ELISA analyzer is developed. The system is one core module of the fully automatic ELISA analyzer. The principle and function of the system is analyzed. Three main units of the system, the photoelectric transform unit, the data processing unit and the communication and control unit, are designed and debugged. Finally, the test of the system is carried out using the verification plate. The experiment results agree well with the requirements.

  13. Leaky Mode Engineering: A General Design Principle for Dielectric Optical Antenna Solar Absorbers

    CERN Document Server

    Yu, Yiling

    2014-01-01

    We present a general principle for the rational design of dielectric optical anatennas with optimal solar absorption: leaky mode engineering. This builds upon our previous study that demonstrates the solar absorption in a given amount of materials dictated by the modal properties of leaky modes. Here we synergistically examine the correlation among the modal properties of leaky modes, the physical features of dielectric structures, and the solar absorption in these structures. Our analysis clearly points out the general guideline for the design of dielectric optical antennas with optimal solar absorption enhenacement: a) using 0D structures; b) the shape does not matter much; c) heterostructuring with non-absorbing materials is a promising strategy; d) the design of a large-scale nanostructure array can literally build upon the design of single nanostructure solar absorbers.

  14. Design of a Quad-Band Wide-Angle Microwave Metamaterial Absorber

    Science.gov (United States)

    Ren, Yu-Hui; Ding, Jun; Guo, Chen-Jiang; Qu, Yan; Song, Yi-Chuan

    2017-01-01

    We report the design, analysis, fabrication, and measurement of a quad-band microwave metamaterial absorber that exhibits four distinct high absorption peaks at specific resonance frequencies. The proposed structure consists of a metallic hexagonal patch layer on top of a dielectric substrate with a metallic film as bottom layer. The simulation and experimental results show that the absorber presents four distinctive perfect (>90%) absorption peaks up to incidence angle of 40° for both transverse electric and transverse magnetic modes. The results prove that this kind of quad-band absorber has good performance over a wide incidence angle range and is polarization insensitive. Moreover, the experimental and numerical simulation results are essentially in agreement.

  15. Analysis and Design of Ultra Thin Electromagnetic Absorbers Comprising Resistively Loaded High Impedance Surfaces

    CERN Document Server

    Costa, Filippo; Manara, Giuliano; 10.1109/TAP.2010.2044329

    2010-01-01

    High-Impedance Surfaces (HIS) comprising lossy Frequency Selective Surfaces (FSS) are employed to design thin electromagnetic absorbers. The structure, despite its typical resonant behavior, is able to perform a very wideband absorption in a reduced thickness. Losses in the frequency selective surface are introduced by printing the periodic pattern through resistive inks and hence avoiding the typical soldering of a large number of lumped resistors. The effect of the surface resistance of the FSS and dielectric substrate characteristics on the input impedance of the absorber is discussed by means of a circuital model. It is shown that the optimum value of surface resistance is affected both by substrate parameters (thickness and permittivity) and by FSS element shape. The equivalent circuit model is then used to introduce the working principles of the narrowband and the wideband absorbing structure and to derive the best-suited element for wideband absorption. Finally, the experimental validation of the prese...

  16. Design of four-band terahertz perfect absorber based on a simple #-shaped metamaterial resonator

    Science.gov (United States)

    Hu, Dan; Wang, Hongyan; Tang, Zhenjie; Zhang, Xiwei; Zhu, Qiaofen

    2016-09-01

    We propose a simple and novel design of four-band terahertz perfect metamaterial absorber composed of a periodic arrangement of metallic #-shaped strip and a metallic background plane, separated by a dielectric polyimide spacer. Theoretical results show that the proposed absorber has four distinct absorption bands whose peaks are average over 99 %. Different from previous reports by combining the resonances of the complex structure (coplanar super-unit structure or stacked multilayer structure) to realize multiband response, the proposed structure primarily utilizes the combination of LC and electric dipole resonances of the single patterned structure, thus making the proposed structure very easy to be fabricated. Furthermore, sensing performance of the absorber is analyzed in terms of the over-layer and the surrounding index.

  17. Modelling of TES X-ray Microcalorimeters with a Novel Absorber Design

    Science.gov (United States)

    Iyomoto, Naoko; Bandler, Simon; Brefosky, Regis; Brown, Ari; Chervenak, James; Figueroa-Feliciano, Enectali; Finkbeiner, Frederick; Kelley, Richard; Kilbourne, Caroline; Lindeman, Mark; Porter, Frederick; Saab, Tarek; Sadleir, Jack; Smith, Stephen

    2007-01-01

    Our development of a novel x-ray absorber design that has enabled the incorporation of high-conductivity electroplated gold into our absorbers has yielded devices that not only have achieved breakthrough performance at 6 keV, but also are extraordinarily well modelled. We have determined device parameters that reproduce complex impedance curves and noise spectra throughout transition. Observed pulse heights, decay time and baseline energy resolution were in good agreement with simulated results using the same parameters. In the presentation, we will show these results in detail and we will also show highlights of the characterization of our gold/bismuth-absorber devices. We will discuss possible improvement of our current devices and expected performance of future devices using the modelling results.

  18. APPLICATION OF MODERN ROBUST OPTIMAL DESIGN METHOD TO THE SHOCK ABSORBER IN A CAR

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    To reduce the variation of velocity characteristic of the shock absorber in a car, a modern robust optimal design method is applied to its structural parameters design. Firstly, the method is used to obtain the robust values which have low sensitivity to velocity characteristic and analyze the influences of the parameters on velocity characteristic. Secondly, the method is used to obtain their maximum tolerances under the condition of ensuring product quality. The results obviously improve the velocity characteristic.

  19. Nodal Green’s Function Method Singular Source Term and Burnable Poison Treatment in Hexagonal Geometry

    Energy Technology Data Exchange (ETDEWEB)

    A.A. Bingham; R.M. Ferrer; A.M. ougouag

    2009-09-01

    An accurate and computationally efficient two or three-dimensional neutron diffusion model will be necessary for the development, safety parameters computation, and fuel cycle analysis of a prismatic Very High Temperature Reactor (VHTR) design under Next Generation Nuclear Plant Project (NGNP). For this purpose, an analytical nodal Green’s function solution for the transverse integrated neutron diffusion equation is developed in two and three-dimensional hexagonal geometry. This scheme is incorporated into HEXPEDITE, a code first developed by Fitzpatrick and Ougouag. HEXPEDITE neglects non-physical discontinuity terms that arise in the transverse leakage due to the transverse integration procedure application to hexagonal geometry and cannot account for the effects of burnable poisons across nodal boundaries. The test code being developed for this document accounts for these terms by maintaining an inventory of neutrons by using the nodal balance equation as a constraint of the neutron flux equation. The method developed in this report is intended to restore neutron conservation and increase the accuracy of the code by adding these terms to the transverse integrated flux solution and applying the nodal Green’s function solution to the resulting equation to derive a semi-analytical solution.

  20. A universal design to realize a tunable perfect absorber from infrared to microwaves

    Science.gov (United States)

    Smaali, Rafik; Omeis, Fatima; Moreau, Antoine; Taliercio, Thierry; Centeno, Emmanuel

    2016-01-01

    We propose a design for an universal absorber, characterized by a resonance frequency that can be tuned from visible to microwave frequencies independently of the choice of the metal and the dielectrics involved. An almost perfect absorption up to 99.8% is demonstrated at resonance for all polarization states of light and for a very wide angular aperture. These properties originate from a magnetic Fabry-Perot mode that is confined in a dielectric spacer of λ/100 thickness by a metamaterial layer and a mirror. An extraordinary large funneling through nano-slits explains how light can be trapped in the structure. Simple scaling laws can be used as a recipe to design ultra-thin perfect absorbers whatever the materials and the desired resonance wavelength, making our design truly universal. PMID:27599634

  1. Multi level optimization of burnable poison utilization for advanced PWR fuel management

    Science.gov (United States)

    Yilmaz, Serkan

    The objective of this study was to develop an unique methodology and a practical tool for designing burnable poison (BP) pattern for a given PWR core. Two techniques were studied in developing this tool. First, the deterministic technique called Modified Power Shape Forced Diffusion (MPSFD) method followed by a fine tuning algorithm, based on some heuristic rules, was developed to achieve this goal. Second, an efficient and a practical genetic algorithm (GA) tool was developed and applied successfully to Burnable Poisons (BPs) placement optimization problem for a reference Three Mile Island-1 (TMI-1) core. This thesis presents the step by step progress in developing such a tool. The developed deterministic method appeared to perform as expected. The GA technique produced excellent BP designs. It was discovered that the Beginning of Cycle (BOC) Kinf of a BP fuel assembly (FA) design is a good filter to eliminate invalid BP designs created during the optimization process. By eliminating all BP designs having BOC Kinf above a set limit, the computational time was greatly reduced since the evaluation process with reactor physics calculations for an invalid solution is canceled. Moreover, the GA was applied to develop the BP loading pattern to minimize the total Gadolinium (Gd) amount in the core together with the residual binding at End-of-Cycle (EOC) and to keep the maximum peak pin power during core depletion and Soluble boron concentration at BOC both less than their limit values. The number of UO2/Gd2O3 pins and Gd 2O3 concentrations for each fresh fuel location in the core are the decision variables and the total amount of the Gd in the core and maximum peak pin power during core depletion are in the fitness functions. The use of different fitness function definition and forcing the solution movement towards to desired region in the solution space accelerated the GA runs. Special emphasize is given to minimizing the residual binding to increase core lifetime as

  2. A metamaterial absorber for the terahertz regime: Design, fabrication and characterization

    OpenAIRE

    Tao, Hu; Landy, Nathan I.; Bingham, Christopher M.; Xin ZHANG; Averitt, Richard D.; Padilla, Willie J.

    2008-01-01

    We present a metamaterial that acts as a strongly resonant absorber at terahertz frequencies. Our design consists of a bilayer unit cell which allows for maximization of the absorption through independent tuning of the electrical permittivity and magnetic permeability. An experimental absorptivity of 70% at 1.3 terahertz is demonstrated. We utilize only a single unit cell in the propagation direction, thus achieving an absorption coefficient $\\alpha$ = 2000 cm$^{-1}$. These metamaterials are ...

  3. Design, simulation and optimization of a solar dish collector with spiral-coil thermal absorber

    Directory of Open Access Journals (Sweden)

    Pavlović Saša R.

    2016-01-01

    Full Text Available The efficient conversion of solar radiation into heat at high temperature levels requires the use of concentrating solar collectors. The goal of this paper is to present the optical and the thermal analysis of a parabolic dish concentrator with a spiral coil receiver. The parabolic dish reflector consists of 11 curvilinear trapezoidal reflective petals constructed by PMMA with silvered mirror layer and has a diameter of 3.8 m, while its focal distance is 2.26m. This collector is designed with commercial software SolidWorks and simulated, optically and thermally in its Flow Simulation Studio. The optical analysis proved that the ideal position of the absorber is at 2.1m from the reflector in order to maximize the optical efficiency and to create a relative uniform heat flux over the absorber. In thermal part of the analysis, the energetic efficiency was calculated approximately 65%, while the exergetic efficiency is varied from 4% to 15% according to the water inlet temperature. Moreover, other important parameters as the heat flux and temperature distribution over the absorber are presented. The pressure drop of the absorber coil is calculated at 0.07bar, an acceptable value.

  4. Absorbable energy monitoring scheme: new design protocol to test vehicle structural crashworthiness

    Directory of Open Access Journals (Sweden)

    Sunday M. Ofochebe

    2016-05-01

    Full Text Available In vehicle crashworthiness design optimization detailed system evaluation capable of producing reliable results are basically achieved through high-order numerical computational (HNC models such as the dynamic finite element model, mesh-free model etc. However the application of these models especially during optimization studies is basically challenged by their inherent high demand on computational resources, conditional stability of the solution process, and lack of knowledge of viable parameter range for detailed optimization studies. The absorbable energy monitoring scheme (AEMS presented in this paper suggests a new design protocol that attempts to overcome such problems in evaluation of vehicle structure for crashworthiness. The implementation of the AEMS involves studying crash performance of vehicle components at various absorbable energy ratios based on a 2DOF lumped-mass-spring (LMS vehicle impact model. This allows for prompt prediction of useful parameter values in a given design problem. The application of the classical one-dimensional LMS model in vehicle crash analysis is further improved in the present work by developing a critical load matching criterion which allows for quantitative interpretation of the results of the abstract model in a typical vehicle crash design. The adequacy of the proposed AEMS for preliminary vehicle crashworthiness design is demonstrated in this paper, however its extension to full-scale design-optimization problem involving full vehicle model that shows greater structural detail requires more theoretical development.

  5. Absorbable energy monitoring scheme: new design protocol to test vehicle structural crashworthiness.

    Science.gov (United States)

    Ofochebe, Sunday M; Enibe, Samuel O; Ozoegwu, Chigbogu G

    2016-05-01

    In vehicle crashworthiness design optimization detailed system evaluation capable of producing reliable results are basically achieved through high-order numerical computational (HNC) models such as the dynamic finite element model, mesh-free model etc. However the application of these models especially during optimization studies is basically challenged by their inherent high demand on computational resources, conditional stability of the solution process, and lack of knowledge of viable parameter range for detailed optimization studies. The absorbable energy monitoring scheme (AEMS) presented in this paper suggests a new design protocol that attempts to overcome such problems in evaluation of vehicle structure for crashworthiness. The implementation of the AEMS involves studying crash performance of vehicle components at various absorbable energy ratios based on a 2DOF lumped-mass-spring (LMS) vehicle impact model. This allows for prompt prediction of useful parameter values in a given design problem. The application of the classical one-dimensional LMS model in vehicle crash analysis is further improved in the present work by developing a critical load matching criterion which allows for quantitative interpretation of the results of the abstract model in a typical vehicle crash design. The adequacy of the proposed AEMS for preliminary vehicle crashworthiness design is demonstrated in this paper, however its extension to full-scale design-optimization problem involving full vehicle model that shows greater structural detail requires more theoretical development.

  6. LBNF Hadron Absorber: Mechanical Design and Analysis for 2.4MW Operation

    Energy Technology Data Exchange (ETDEWEB)

    Hartsell, B. [Fermilab; Anderson, K. [Fermilab; Hylen, J. [Fermilab; Sidorov, V. [Fermilab; Tariq, S. [Fermilab

    2015-06-01

    Fermilab’s Long-Baseline Neutrino Facility (LBNF) requires an absorber, essentially a large beam dump consisting of actively cooled aluminum and steel blocks, at the end of the decay pipe to stop leftover beam particles and provide radiation protection to people and groundwater. At LBNF’s final beam power of 2.4 MW and assuming the worst case condition of a 204 m long helium filled decay pipe, the absorber is required to handle a heat load of about 750 kW. This results in significant thermal management challenges which have been mitigated by the addition of an aluminum ‘spoiler’ and ‘sculpting’ the central portion of the aluminum core blocks. These thermal effects induce structural stresses which can lead to fatigue and creep considerations. Various accident conditions are considered and safety systems are planned to monitor operation and any accident pulses. Results from these thermal and structural analyses will be presented as well as the mechanical design of the absorber. The design allows each of the core blocks to be remotely removed and replaced if necessary. A shielded remote handling structure is incorporated to hold the hadron monitor when it is removed from the beam.

  7. Design Guidelines for Ferrite Absorbers Submitted to RF-induced Heating

    CERN Document Server

    Bertarelli, A

    2013-01-01

    The use of ferrite absorbers is one of the most effective means of damping potentially harmful high order RF modes, which may lead to beam instabilities and excessive power losses in accelerator devices. However, the power deposited on ferrite absorbers themselves maylead to ferrite exceeding its Curie temperature, losing its damping properties. An evaluation of the ferrite capability to dissipate deposited heat is hence of paramount importance for the safe design of particle accelerator devices. In this paper, figures of merit are proposed to assess the maximum specific power allowed on a generic ferrite tile, before it reaches its Curie temperature. Due to its inherent brittleness, sufficient contact pressure between ferrite and its housing, allowing heat transmission by conduction, can hardly be applied. A semi-analytical study is thus performed, assuming that ferrite is evacuating heat solely through radiation. The described method is then exemplified in the case of the BPM-embedded tertiary collimator (T...

  8. Mechanical Design of a High Energy Beam Absorber for the Advanced Superconducting Test Accelerator (ASTA) at Fermilab

    CERN Document Server

    Baffes, C; Leibfritz, J; Oplt, S; Rakhno, I

    2013-01-01

    A high energy beam absorber has been built for the Advanced Superconducting Test Accelerator (ASTA) at Fermilab. In the facility's initial configuration, an electron beam will be accelerated through 3 TTF-type or ILC-type RF cryomodules to an energy of 750MeV. The electron beam will be directed to one of multiple downstream experimental and diagnostic beam lines and then deposited in one of two beam absorbers. The facility is designed to accommodate up to 6 cryomodules, which would produce a 75kW beam at 1.5GeV; this is the driving design condition for the beam absorbers. The beam absorbers consist of water-cooled graphite, aluminum and copper layers contained in a Helium-filled enclosure. This paper describes the mechanical implementation of the beam absorbers, with a focus on thermal design and analysis. In addition, the potential for radiation-induced degradation of the graphite is discussed.

  9. Mechanical Design of a High Energy Beam Absorber for the Advanced Superconducting Test Accelerator (ASTA) at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Baffes, C.; Church, M.; Leibfritz, J.; Oplt, S.; Rakhno, I.; /Fermilab

    2012-05-10

    A high energy beam absorber has been built for the Advanced Superconducting Test Accelerator (ASTA) at Fermilab. In the facility's initial configuration, an electron beam will be accelerated through 3 TTF-type or ILC-type SRF cryomodules to an energy of 750MeV. The electron beam will be directed to one of multiple downstream experimental and diagnostic beam lines and then deposited in one of two beam absorbers. The facility is designed to accommodate up to 6 cryomodules, which would produce a 75kW beam at 1.5GeV; this is the driving design condition for the beam absorbers. The beam absorbers consist of water-cooled graphite, aluminum and copper layers contained in a helium-filled enclosure. This paper describes the mechanical implementation of the beam absorbers, with a focus on thermal design and analysis. The potential for radiation-induced degradation of the graphite is discussed.

  10. Effects of limestone petrography and calcite microstructure on OPC clinker raw meals burnability

    Science.gov (United States)

    Galimberti, Matteo; Marinoni, Nicoletta; Della Porta, Giovanna; Marchi, Maurizio; Dapiaggi, Monica

    2016-12-01

    Limestone represents the main raw material for ordinary Portland cement clinker production. In this study eight natural limestones from different geological environments were chosen to prepare raw meals for clinker manufacturing, aiming to define a parameter controlling the burnability. First, limestones were characterized by X-Ray Fluorescence, X-Ray Powder Diffraction and Optical Microscopy to assess their suitability for clinker production and their petrographic features. The average domains size and the microstrain of calcite were also determined by X-Ray Powder Diffraction line profile analysis. Then, each limestone was admixed with clay minerals to achieve the adequate chemical composition for clinker production. Raw meals were thermally threated at seven different temperatures, from 1000 to 1450 °C, to evaluate their behaviour on heating by ex situ X-Ray Powder Diffraction and to observe the final clinker morphology by Scanning Electron Microscopy. Results indicate the calcite microstrain is a reliable parameter to predict the burnability of the raw meals, in terms of calcium silicates growth and lime consumption. In particular, mixtures prepared starting from high-strained calcite exhibit a better burnability. Later, when the melt appears this correlation vanishes; however differences in the early burnability still reflect on the final clinker composition and texture.

  11. Multi-objective optimal design of active vibration absorber with delayed feedback

    Science.gov (United States)

    Huan, Rong-Hua; Chen, Long-Xiang; Sun, Jian-Qiao

    2015-03-01

    In this paper, a multi-objective optimal design of delayed feedback control of an actively tuned vibration absorber for a stochastically excited linear structure is investigated. The simple cell mapping (SCM) method is used to obtain solutions of the multi-objective optimization problem (MOP). The continuous time approximation (CTA) method is applied to analyze the delayed system. Stability is imposed as a constraint for MOP. Three conflicting objective functions including the peak frequency response, vibration energy of primary structure and control effort are considered. The Pareto set and Pareto front for the optimal feedback control design are presented for two examples. Numerical results have found that the Pareto optimal solutions provide effective delayed feedback control design.

  12. Design of high performance multilayer microwave absorbers using fast Pareto genetic algorithm

    Institute of Scientific and Technical Information of China (English)

    JIANG LiYong; LI XiangYin; ZHANG Jie

    2009-01-01

    The application of the Non-dominated Sorting Genetic Algorithm Ⅱ (NSGA-Ⅱ) in designing microwave absorbers is described in this paper. To obtain high performance coatings, we put forward three cost functions, which represent three objectives of strong-absorption, broad-bandwidth and thin structure, and study the tradeoffs between each other. Numerical calculations on available materials in 2-18 GHz are implemented to construct the Pareto front and Pareto-optimal surface for two and three objectives respectively. Results indicate that the NSGA-Ⅱ can work more efficiently and effectively than traditional Pareto genetic algorithms. Additionally, we present several particular designs from the above Pareto front (surface) for potential applications in different frequency bands. For example, a four-layer ab-sorber with thickness of 2.8071 mm is obtained to provide average reflection coefficient of -11.95 dB and average reflection bandwidth of 0.5780 in 2-18 GHz, considering arbitrary incident angles (0°-89°) and both TE and TM polarizations.

  13. Improved design of dynamic vibration absorber by using the inerter and its application in vehicle suspension

    Science.gov (United States)

    Shen, Yujie; Chen, Long; Yang, Xiaofeng; Shi, Dehua; Yang, Jun

    2016-01-01

    Inerter is a recently proposed mechanical element with two terminals. The novelty of this paper is to present the improved design which aims to add traditional dynamic vibration absorber to the vehicle body by using the inerter. Based on this background, a new vehicle suspension structure called ISD suspension, including the inerter, spring and damper has been created. A dual-mass vibration model including the ISD suspension is considered in this study. Parameters are obtained by using the genetic optimizing algorithm. The frequency-domain simulation confirms that the ISD suspension can effectively improve the damping performance of the suspension system, especially at the offset frequency of the vehicle body, which is consistent with the feature of the dynamic vibration absorber added to the vehicle body mass. At last, a prototype ball screw inerter has been designed and the bench test of a quarter-car model has been undertaken. Under the conditions of the random road input, the vehicle ride comfort evaluation of body acceleration RMS value decreases by 4% at most, the suspension deflection RMS value decreases by 16% at most, the tire dynamic load RMS value decreases by 6% at most. Power spectral density results also indicate that the ISD suspension has superior damping performance than passive suspension which proves that the proposed ISD suspension is deemed effective.

  14. Design of high performance multilayer microwave absorbers using fast Pareto genetic algorithm

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The application of the Non-dominated Sorting Genetic Algorithm Ⅱ (NSGA-Ⅱ) in designing microwave absorbers is described in this paper. To obtain high performance coatings,we put forward three cost functions,which represent three objectives of strong-absorption,broad-bandwidth and thin structure,and study the tradeoffs between each other. Numerical calculations on available materials in 2―18 GHz are implemented to construct the Pareto front and Pareto-optimal surface for two and three objectives respectively. Results indicate that the NSGA-Ⅱ can work more efficiently and effectively than traditional Pareto genetic algorithms. Additionally,we present several particular designs from the above Pareto front (surface) for potential applications in different frequency bands. For example,a four-layer absorber with thickness of 2.8071 mm is obtained to provide average reflection coefficient of -11.95 dB and average reflection bandwidth of 0.5780 in 2―18 GHz,considering arbitrary incident angles (0°―89°) and both TE and TM polarizations.

  15. Effective non-retarded method as a tool for the design of tunable nanoparticle composite absorbers

    CERN Document Server

    Ortiz, Guillermo; Skigin, Diana; Depine, Ricardo; Mochán, Luis

    2014-01-01

    We investigate the capabilities of the effective non-retarded method (ENR) to explore and design nanoparticles composites with specific optical properties. We consider a composite material comprising periodically distributed metallic spheres in a dielectric host matrix. The effective macroscopic dielectric function of the composite medium is obtained by means of the ENR and is used to calculate the electromagnetic response of a slab made of such an inhomogeneous material. This response is compared with that obtained using the Korringa-Kohn-Rostoker wave calculation method (KKR). We analyze the optical properties for different filling fractions, especially in the vicinity of the resonance frequencies of the macroscopic dielectric function. We show that appropriately choosing the parameters of the composite it is possible to achieve a tunable absorber film. The ENR results to be a versatile tool for the design of nanoparticle composite materials with specific properties.

  16. A strain-absorbing design for tissue-machine interfaces using a tunable adhesive gel

    Science.gov (United States)

    Lee, Sungwon; Inoue, Yusuke; Kim, Dongmin; Reuveny, Amir; Kuribara, Kazunori; Yokota, Tomoyuki; Reeder, Jonathan; Sekino, Masaki; Sekitani, Tsuyoshi; Abe, Yusuke; Someya, Takao

    2014-12-01

    To measure electrophysiological signals from the human body, it is essential to establish stable, gentle and nonallergic contacts between the targeted biological tissue and the electrical probes. However, it is difficult to form a stable interface between the two for long periods, especially when the surface of the biological tissue is wet and/or the tissue exhibits motion. Here we resolve this difficulty by designing and fabricating smart, stress-absorbing electronic devices that can adhere to wet and complex tissue surfaces and allow for reliable, long-term measurements of vital signals. We demonstrate a multielectrode array, which can be attached to the surface of a rat heart, resulting in good conformal contact for more than 3 h. Furthermore, we demonstrate arrays of highly sensitive, stretchable strain sensors using a similar design. Ultra-flexible electronics with enhanced adhesion to tissue could enable future applications in chronic in vivo monitoring of biological signals.

  17. A New Absorbable Synthetic Substitute With Biomimetic Design for Dural Tissue Repair.

    Science.gov (United States)

    Shi, Zhidong; Xu, Tao; Yuan, Yuyu; Deng, Kunxue; Liu, Man; Ke, Yiquan; Luo, Chengyi; Yuan, Tun; Ayyad, Ali

    2016-04-01

    Dural repair products are evolving from animal tissue-derived materials to synthetic materials as well as from inert to absorbable features; most of them lack functional and structural characteristics compared with the natural dura mater. In the present study, we evaluated the properties and tissue repair performance of a new dural repair product with biomimetic design. The biomimetic patch exhibits unique three-dimensional nonwoven microfiber structure with good mechanical strength and biocompatibility. The animal study showed that the biomimetic patch and commercially synthetic material group presented new subdural regeneration at 90 days, with low level inflammatory response and minimal to no adhesion formation detected at each stage. In the biological material group, no new subdural regeneration was observed and severe adhesion between the implant and the cortex occurred at each stage. In clinical case study, there was no cerebrospinal fluid leakage, and all the postoperation observations were normal. The biomimetic structure and proper rate of degradation of the new absorbable dura substitute can guide the meaningful reconstruction of the dura mater, which may provide a novel approach for dural defect repair.

  18. Sound Absorbers

    Science.gov (United States)

    Fuchs, H. V.; Möser, M.

    Sound absorption indicates the transformation of sound energy into heat. It is, for instance, employed to design the acoustics in rooms. The noise emitted by machinery and plants shall be reduced before arriving at a workplace; auditoria such as lecture rooms or concert halls require a certain reverberation time. Such design goals are realised by installing absorbing components at the walls with well-defined absorption characteristics, which are adjusted for corresponding demands. Sound absorbers also play an important role in acoustic capsules, ducts and screens to avoid sound immission from noise intensive environments into the neighbourhood.

  19. Optimal design of vibration absorber using minimax criterion with simplified constraints

    Institute of Scientific and Technical Information of China (English)

    Jie Fang; Shi-Min Wang; Qi Wang

    2012-01-01

    In this paper,a minimax design of damped dynamic vibration absorber for a damped primary system is investigated to minimize the vibration magnitude peaks.Moreover,to reduce the sensitivity of the primary system response to variations of the forcing frequency for a twodegree-of-freedom system,the primary system should have two equal resonance magnitude peaks.To meet this requirement,a set of simplified constraint equations including distribution characteristics of the resonant frequencies of the primary system is established for the minimax objective function.The modified constraint equations have less unknown variables than those by other authors,which not only simplifies the computation but also improves the accuracy of the optimal values.The advantage of the proposed method is illustrated through numerical simulations.

  20. Design and Fabrication of Edge Filter Using Absorbed ZnS Single Layer Prepared by Flash Evaporation Technique

    Science.gov (United States)

    Habubi, Nadir F.; Mishjil, Khudheir A.; Rashid, Hayfa G.; Mansour, H. L.

    Long-wave pass edge filter of high transmittance and wide bandpass have been designed and fabricated using on a single weakly absorbed ZnS thin film material of thickness of about 300 nm which was prepared by using the flash evaporation technique. The design was based on characteristic matrix theory, taking into account the effect of dispersion phenomena for all spectral wavelength.

  1. A semi-analytical numerical method for fast metamaterial absorber design

    Directory of Open Access Journals (Sweden)

    Y. C. Song

    2015-09-01

    Full Text Available In this paper, a semi-analytical numerical approach utilizing a novel non-grounded model and interpolation technique is introduced to design the frequency selective surface (FSS based metamaterial absorbers (MAs with dramatically reduced time consumption. Different from commonly used trial-and-error technology, our method mainly utilize the numerically computed FSS layer impedance with slow-varying feature in the vicinity of operating frequency. The introduced non-grounded model establishes the quantitative relationship between geometry parameters and equivalent lumped circuit components in conventional transmission line (TL model with reasonable accuracy. The interpolation technique, on the other hand, promises a relative sparse parameter sweep. The detailed design flow as well as analytical explanation with carefully deduced expressions is presented. With the purpose of validating the proposed method and analytical models, a MA with slotted patches is designed through both the semi-analytical numerical approach and the trial-and-error method, where an over 2300 times acceleration is observed. Additionally, results from the analytical computation and full wave simulation agree well with each other.

  2. Effective non-retarded method as a tool for the design of tunable nanoparticle composite absorbers

    Science.gov (United States)

    Ortiz, Guillermo; Inchaussandague, Marina; Skigin, Diana; Depine, Ricardo; Mochán, W. Luis

    2014-10-01

    We investigate the capabilities of an effective non-retarded formalism (ENR) for the exploration and design of nanoparticle composites with specific optical properties. We consider a composite material comprising periodically distributed metallic spheres in a dielectric host matrix. The effective macroscopic dielectric function of the composite medium is obtained by means of the ENR and is used to calculate the electromagnetic response of a slab made of an inhomogeneous material. This response is compared with that obtained by using the layer Korringa-Kohn-Rostoker wave calculation method (LKKR). We analyze the optical properties for different filling fractions, especially in the vicinity of the resonance frequencies of the macroscopic dielectric function. We notice that for dense systems within the long wavelength regime, the results of some analytical theories developed by other authors do not properly describe the multipolar excitations and interactions of orders higher than the dipole, in contrast with the results obtained by using an ENR. Therefore, those methods are not suitable for the design of compound films with novel properties. We show that by appropriately choosing the parameters of the composite, it is possible to achieve a tunable absorber film, and more generally, we show that ENR is a versatile tool for the design of nanoparticle composite materials with specific properties.

  3. Engineering design feasibility of low boron concentration core in PWR

    Energy Technology Data Exchange (ETDEWEB)

    Daing, A. T.; Kim, M. H. [Kyung Hee University, Yongin-shi, Gyeonggi-do, 446-701 Republic of Korea (Korea, Republic of); Woo, I.; Shon, S. R., E-mail: atdaing@khu.ac.k [Korea Nuclear Fuel, 1047 Daedukdaero, Yuseong-gu, Daejeon, 305-353 Republic of Korea (Korea, Republic of)

    2010-10-15

    In pressurized water reactor operation, higher level of soluble boron concentration could contribute higher impact from boron dilution situations, higher amount of liquid waste, and higher radiation dose to operators from higher corrosion potential to cladding and structure. Two practical and feasible means to reduce the maximum boron concentration were investigated in this study. A technically straightforward, possible means, can be achieved either by implementation of enriched boric acid (Eba) or by increasing more shim rod (fixed burnable absorber) worth. A simplest option is that the Eba is applied into reference core (Ref) design, OPR-1000 design, Ulchin unit-5 by allowing use of same fuel assemblies and core design without changing any nuclear design methodology used in that Ref design. Although results of Eba option proved its favorable power distribution and peaking factor, its moderator temperature coefficient (MTC) value reached positive, 3.25 pcm/ C at 40 EFPD which is beyond the design safety limit. An alternative option with more shim rods in fuel assemblies was tried with four types of integral burnable absorbers: gadolinia, integral fuel burnable absorber (Ifba), erbium and alumina boron carbide. Four core design candidates have been developed by keeping major engineering designs and preserving equivalent fuel enrichment level used in Ref design. However, all optimal designs were targeted to achieve comparable discharge burnup as well as favorable design safety parameters. The comparative analysis between Ref and optimal core designs is presented here. One of them is suggested as the most promising and favorable low boron core (Lbc) design in this framework. The proper combination of axial and radial enrichment zoning pattern in Lbc design candidate with Ifba-bearing fuel assemblies at equilibrium cycle, could bring 2 times narrower axial offset variation than that of Ref design, and maintain acceptable power peaking factor around 23% lower than

  4. Lumbar load attenuation for rotorcraft occupants using a design methodology for the seat impact energy-absorbing system

    Science.gov (United States)

    Moradi, Rasoul; Beheshti, Hamid; Lankarani, Hamid

    2012-12-01

    Aircraft occupant crash-safety considerations require a minimum cushion thickness to limit the relative vertical motion of the seat-pelvis during high vertical impact loadings in crash landings or accidents. In military aircraft and helicopter seat design, due to the potential for high vertical accelerations in crash scenarios, the seat system must be provided with an energy absorber to attenuate the acceleration level sustained by the occupants. Because of the limited stroke available for the seat structure, the design of the energy absorber becomes a trade-off problem between minimizing the stroke and maximizing the energy absorption. The available stroke must be used to prevent bottoming out of the seat as well as to absorb maximum impact energy to protect the occupant. In this study, the energy-absorbing system in a rotorcraft seat design is investigated using a mathematical model of the occupant/seat system. Impact theories between interconnected bodies in multibody mechanical systems are utilized to study the impact between the seat pan and the occupant. Experimental responses of the seat system and the occupant are utilized to validate the results from this study for civil and military helicopters according to FAR 23 and 25 and MIL-S-58095 requirements. A model for the load limiter is proposed to minimize the lumbar load for the occupant by minimizing the relative velocity between the seat pan and the occupant's pelvis. The modified energy absorber/load limiter is then implemented for the seat structure so that it absorbs the energy of impact in an effective manner and below the tolerable limit for the occupant in a minimum stroke. Results show that for a designed stroke, the level of occupant lumbar spine injury would be significantly attenuated using this modified energy-absorber system.

  5. Design of multiple-layer microwave absorbing structure based on rice husk and carbon nanotubes

    Science.gov (United States)

    Seng, Lee Yeng; Wee, F. H.; Rahim, H. A.; AbdulMalek, MohamedFareq; You, Y. K.; Liyana, Z.; Ezanuddin, A. A. M.

    2017-01-01

    This paper presents a multiple-layered microwave absorber using rice husk and carbon nanotube composite. The dielectric properties of each layer composite were measured and analysed. The different layer of microwave absorber enables to control the microwave absorption performance. The microwave absorption performances are demonstrated through measurements of reflectivity over the frequency range 2-18 GHz. An improvement of microwave absorption application as wideband electromagnetic wave absorbers.

  6. Design and Evaluation of Ionic Liquids as Novel CO2 Absorbents

    Energy Technology Data Exchange (ETDEWEB)

    Edward J. Maginn

    2006-01-12

    Progress from the fourth quarter 2005 activity on the project ''Design and Evaluation of Ionic Liquids as Novel CO{sub 2} Absorbents'' is provided. Major activities in three areas are reported: compound synthesis, property measurement and molecular modeling. Last quarter we reported the first ever experimental measurement of SO{sub 2} solubility in an ionic liquid. We showed that SO{sub 2} was very soluble in the ionic liquid 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([hmim][Tf{sub 2}N]). This quarter, we have measured SO{sub 2} solubility in two more ionic liquids: 1-hexyl-3-methylpyridinium bis(trifluoromethanesulfonyl)imide ([hmpy][Tf{sub 2}N]) and 1-hexyl-3-methylimidazolium lactate ([hmim][lactate]). As with [hmim][Tf{sub 2}N], we find very high solubility of SO{sub 2} in these ionic liquids, but the lactate compounds shows the highest affinity for SO{sub 2} at low pressure. CO{sub 2} solubility was measured in three new compounds: [boronium][Tf{sub 2}N], 1-hexyl-3-methylimidazolium acesulfumate ([hmim][ace]), and 1-hexyl-3-methylimidazolium saccharinate ([hmim][sac]). We find relatively poor solubility of CO{sub 2} in the latter two compounds, and solubility comparable to [hmim][Tf{sub 2}N] in the boronium compound. We also synthesized four new ionic liquids this quarter and continued refinement of our molecular simulation technique for measuring gas solubility.

  7. Design of dual Beam multi-wavelength UV-visible absorbance detectors based on CCD

    Institute of Scientific and Technical Information of China (English)

    SHEN Shuang; TANG Zhen-an; LI Tong

    2006-01-01

    @@ Because the general multi-wavelength UV-Visible absorbance detector cannot avoid the noise and drift resulting from the intensity fluctuation of the light source,a dual beam multi-wavelength UV-Visible detector based on CCD was designed.The ray of light source is divided into a signal ray and a reference ray by the beam splitter after it passes through the chopper.The signal ray shines into the sample cell.The signal ray passing through the sample cell falls onto a concave mirror which focuses it onto a slot that is imaged on one portion of CCD by a concave grating.The reference ray is imaged on the other portion of CCD by the concave grating after the slot.The signal spectrum,the reference spectrum and the dark current of CCD can be measured on the same CCD under the cooperation of the optical system and accessorial circuits.The real-time compensation for the signal spectrum by using the reference spectrum and the dark current of CCD can effectively depress the noise and drift of the detector.The short-term noise is 10-5AU and the drift is 10-4AU/h.

  8. Fluorescence modulation by absorbent on solid surface: an improved approach for designing fluorescent sensor.

    Science.gov (United States)

    Yang, Sheng; Wang, Changyao; Liu, Changhui; Wang, Yijun; Xiao, Yue; Li, Jishan; Li, Yinhui; Yang, Ronghua

    2014-08-05

    Inner filter effect (IFE), a well-known phenomenon of fluorescence quenching resulting from absorption of the excitation or emission light of luminescent species by absorbent, has been used as a smart approach to design fluorescent sensors, which are characterized by the simplicity and flexibility with high sensitivity. However, further application of IFE-based sensors in complex environment is hampered by the insufficient IFE efficiency and low sensitivity resulting from interference of the external environment. In this paper, we report that IFE occurring on a solid substrate surface would solve this problem. As a proof of concept, a fluorescent sensor for intracellular biothiols has been developed on the basis of the absorption of a newly designed thiols-specific chromogenic probe (CP) coupled with the use of a thiols-independent fluorophore, rhodamine 6G (R6G), operative on the IFE on graphene oxide (GO). To construct an efficient IFE system, R6G was covalently attached to GO, and the CP molecules were adsorbed on the surface of R6G-GO via π-π stacking interaction. The reaction of thiols with CP on R6G-GO decreases the absorption of CP, resulting in the increase of the intensity of R6G fluorescence. The results showed that the IFE efficiency, sensitivity, and dynamic response time of R6G-GO/CP for biothiols could be significantly improved compared with R6G/CP, and furthermore, R6G-GO/CP functioned under complex system and could be used for assaying biothiols in living cells and in human serum samples. This new strategy would be general to explore the development of more effective IFE-based sensors for other analytes of interest.

  9. Design and performance simulation of a segmented-absorber based muon detection system for high energy heavy ion collision experiments

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, S. [University of Kashmir, Srinagar (India); Bhaduri, P.P. [Variable Energy Cyclotron Centre, Kolkata (India); Jahan, H. [Aligarh Muslim University, Aligarh (India); Senger, A. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Adak, R.; Samanta, S. [Bose Institute, Kolkata (India); Prakash, A. [Banaras Hindu University, Varanasi (India); Dey, K. [Gauhati University, Guwahati (India); Lebedev, A. [Institute für Kernphysik, Goethe Universität Frankfurt, Frankfurt (Germany); Kryshen, E. [Petersburg Nuclear Physics Institute (PNPI) NRC Kurchatov Institute, Gatchina (Russian Federation); Chattopadhyay, S., E-mail: sub@vecc.gov.in [Variable Energy Cyclotron Centre, Kolkata (India); Senger, P. [GSI Helmholtzzentrum fur Schwerionenforschung GmbH, Darmstadt (Germany); Bhattacharjee, B. [Gauhati University, Guwahati (India); Ghosh, S.K.; Raha, S. [Bose Institute, Kolkata (India); Irfan, M.; Ahmad, N. [Aligarh Muslim University, Aligarh (India); Farooq, M. [University of Kashmir, Srinagar (India); Singh, B. [Banaras Hindu University, Varanasi (India)

    2015-03-01

    A muon detection system (MUCH) based on a novel concept using a segmented and instrumented absorber has been designed for high-energy heavy-ion collision experiments. The system consists of 6 hadron absorber blocks and 6 tracking detector triplets. Behind each absorber block a detector triplet is located which measures the tracks of charged particles traversing the absorber. The performance of such a system has been simulated for the CBM experiment at FAIR (Germany) that is scheduled to start taking data in heavy ion collisions in the beam energy range of 6–45 A GeV from 2019. The muon detection system is mounted downstream to a Silicon Tracking System (STS) that is located in a large aperture dipole magnet which provides momentum information of the charged particle tracks. The reconstructed tracks from the STS are to be matched to the hits measured by the muon detector triplets behind the absorber segments. This method allows the identification of muon tracks over a broad range of momenta including tracks of soft muons which do not pass through all the absorber layers. Pairs of oppositely charged muons identified by MUCH could therefore be combined to measure the invariant masses in a wide range starting from low mass vector mesons (LMVM) up to charmonia. The properties of the absorber (material, thickness, position) and of the tracking chambers (granularity, geometry) have been varied in simulations of heavy-ion collision events generated with the UrQMD generator and propagated through the setup using the GEANT3, the particle transport code. The tracks are reconstructed by a Cellular Automaton algorithm followed by a Kalman Filter. The simulations demonstrate that low mass vector mesons and charmonia can be clearly identified in central Au+Au collisions at beam energies provided by the international Facility for Antiproton and Ion Research (FAIR)

  10. Design, fabrication, and characterization of lightweight and broadband microwave absorbing structure reinforced by two dimensional composite lattice

    Science.gov (United States)

    Chen, Mingji; Pei, Yongmao; Fang, Daining

    2012-07-01

    Microwave absorbing structures (MASs) reinforced by two dimensional (2D) composite lattice elements have been designed and fabricated. The density of these MASs is lower than 0.5 g/cm3. Experimental measurements show that the sandwich structure with glass fiber reinforced composite (GFRC) lattice core can serve as a broadband MAS with its reflectivity below -10 dB over the frequency range of 4-18 GHz. The low permittivity GFRC is indicated to be the proper material for both the structural element of the core and the transparent face sheet. Calculations by the periodic moment method (PMM) demonstrate that the 2D Kagome lattice performs better for microwave absorbing than the square one at relatively low frequencies. The volume fraction and cell size of the structural element are also revealed to be key factors for microwave absorbing performance.

  11. Manipulating surface plasmon waves by transformation optics: Design examples of a beam squeezer, bend,and omnidirectional absorber

    Institute of Scientific and Technical Information of China (English)

    Yu Zhen-Zhong; Feng Yi-Jun; Wang Zheng-Bin; Zhao Jun-Ming; Jiang Tian

    2013-01-01

    We present several design examples of how to apply transformation optics and curved space under coordinate transformarion to manipulating the surface plasmon waves in a controlled manner.We demonstrate in detail the design procedure of the plasmonic wave squeezer,in-plane bend and omnidirectional absorber.We show that the approximation method of modifying only the dielectric material of a dielectric-metal surface of the plasmonic device could lead to acceptable performance,which facilitates the fabrication of the device.The functionality of the proposed plasmonic device is verified using three-dimensional full-wave electromagnetic simulations.Aiming at practical realization,we also show the design of a plasmonic in-plane bend and omnidirectional absorber by an alternative transformation scheme,which results in a simple device structure with a tapered isotropic dielectric cladding layer on the top of the metal surface that can be fabricated with existing nanotechnology.

  12. The effects of spectral shift absorbers on the design and safety of fast spectrum space reactors

    Science.gov (United States)

    King, Jeffrey Charles

    Spectral Shift Absorbers (SSAs) are incorporated into space reactors to maintain them sufficiently subcritical when submerged in seawater or wet sand and subsequently flooded, following a launch abort accident. The effect of four SSAs (samarium-149, europium-151, gadolinium-155, and gadolinium-157) on the submersion criticality, operation, and temperature reactivity feedback of the thermal spectrum reactors developed in the Systems for Nuclear Auxilary Power (SNAP) program is extensively documented. Recent work on SSAs in fast spectrum space reactors, preferred for compactness and higher powers, has focused on rhenium as the primary SSA. In addition to identifying additional SSAs, the present work investigates the effects of SSAs on the overall size and mass, temperature reactivity feedback, and operational lifetime of fast spectrum space reactors. The fast spectrum S4 reactor has a sectored Mo-14%Re solid-core, loadedwith UN fuel, cooled by He-30%Xe, and designed to avoid single point failures at a steady thermal power of 550 kWth. The addition of SSAs to the reactor core increases the fuel enrichment and decreases the size and mass of the reactor and the radiation shadow shield. SSA additions of boron-10, europium-151, gadolinium-155 and iridium result in the smallest and lightest S4 reactors. The effects of SSA additions on the operational lifetime and the temperature and burnup reactivity coefficients of the S^4 reactor are studied. An increasein fuel enrichment with SSAs markedly increases the operational lifetime by decreasing the burnup reactivity coefficient with only a slight decrease in the temperature reactivity feedback coefficient. With no SSAs, the UN fuel enrichment is lowest (58.5 wt%), the temperature and burnup reactivity coefficients are the highest (-0.2709 ¢/K and -1.3470 /atom%), and the estimated operating lifetime is the shortest (7.6 years). The temperature and burnup reactivity coefficients decrease to -0.2649 ¢/K and -1.0230 /atom%, and

  13. Design and Evaluation of Ionic Liquids as Novel CO2 Absorbents

    Energy Technology Data Exchange (ETDEWEB)

    Edward Maginn

    2007-07-15

    This is the final report for project DE-FG26-04NT42122 'Design and Evaluation of Ionic Liquids as Novel CO{sub 2} Absorbents'. The objective of this 'breakthrough concepts' project was to investigate the feasibility of using ionic liquids for post-combustion CO{sub 2} capture and obtain a fundamental understanding of the solubility of CO{sub 2} and other components present in flue gas in ionic liquids. Our plan was to obtain information on how composition and structure of ionic liquid molecules affected solubility and other important physical properties via two major efforts: synthesis and experimental measurements and molecular simulation. We also planned to perform preliminary systems modeling study to assess the economic viability of a process based on ionic liquids. We accomplished all the milestones and tasks specified in the original proposal. Specifically, we carried out extensive quantum and classical atomistic-level simulations of a range of ionic liquids. These calculations provided detailed information on how the chemical composition of ionic liquids affects physical properties. We also learned important factors that govern CO{sub 2} solubility. Using this information, we synthesized or acquired 33 new ionic liquids. Many of these had never been made before. We carried out preliminary tests on all of these compounds, and more extensive tests on those that looked most promising for CO{sub 2} capture. We measured CO{sub 2} solubility in ten of these ionic liquids. Through our efforts, we developed an ionic liquid that has a CO{sub 2} solubility 2.6 times greater than the 'best' ionic liquid available to us at the start of the project. Moreover, we demonstrated that SO{sub 2} is also extremely soluble in ionic liquids, opening up the possibility of using ionic liquids to remove both SO{sub 2} and CO{sub 2} from flue gas. In collaboration with Trimeric Inc., a preliminary systems analysis was conducted and the results used to

  14. A Neutronic Feasibility Study of an OPR-1000 Core Design with Boron-bearing Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyung Hoon; Park, Sang Yoon; Lee, Chung Chan; Yang, Yong Sik [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    In Westinghouse plants, boron is mainly used as a form of the integral fuel burnable absorber (IFBA) with a thin coating of zirconium diboride (ZrB{sub 2}) or wet annular burnable absorber (WABA) with a hollow Al{sub 2}O{sub 3}+B{sub 4}C pellet. In OPR-1000, on the other hand, gadolinia is currently employed as a form of an admixture which consists of Gd{sub 2}O{sub 3} of 6∼8 w/o and UO{sub 2} of natural uranium. Recently, boron-bearing UO{sub 2} fuel (BBF) with the high density of greater than 94%TD has been developed by using a low temperature sintering technique. In this paper, the feasibility of replacing conventional gadolinia-bearing UO{sub 2} fuel (GBF) in OPR-1000 with newly developed boron-bearing fuel is evaluated. Neutronic feasibility study to utilize the BBF in OPR-1000 core has been performed. The results show that the OPR-1000 core design with the BBF is feasible and promising in neutronic aspects. Therefore, the use of the BBF in OPR-1000 can reduce the dependency on the rare material such as gadolinium. However, the burnout of the {sup 10}B isotope results in helium gas, so fuel performance related study with respect to helium generation is needed.

  15. Designing a hand rest tremor dynamic vibration absorber using H{sub 2} optimization method

    Energy Technology Data Exchange (ETDEWEB)

    Rahnavard, Mostafa; Dizaji, Ahmad F. [Tehran University, Tehran (Iran, Islamic Republic of); Hashemi, Mojtaba [Amirkabir University, Tehran (Iran, Islamic Republic of); Faramand, Farzam [Sharif University, Tehran (Iran, Islamic Republic of)

    2014-05-15

    An optimal single DOF dynamic absorber is presented. A tremor has a random nature and then the system is subjected to a random excitation instead of a sinusoidal one; so the H{sub 2} optimization criterion is probably more desirable than the popular H{sub ∞} optimization method and was implemented in this research. The objective of H{sub 2} optimization criterion is to reduce the total vibration energy of the system for overall frequencies. An objective function, considering the elbow joint angle, θ {sub 2}, tremor suppression as the main goal, was selected. The optimization was done by minimization of this objective function. The optimal system, including the absorber, performance was analyzed in both time and frequency domains. Implementing the optimal absorber, the frequency response amplitude of θ{sub 2} was reduced by more than 98% and 80% at the first and second natural frequencies of the primary system, respectively. A reduction of more than 94% and 78%, was observed for the shoulder joint angle, θ{sub 1}. The objective function also decreased by more than 46%. Then, two types of random inputs were considered. For the first type, θ{sub 1} and θ {sub 2} revealed 60% and 39% reduction in their rms values, whereas for the second type, 33% and 50% decrease was observed.

  16. Topology optimization design of a lightweight ultra-broadband wide-angle resistance frequency selective surface absorber

    Science.gov (United States)

    Sui, Sai; Ma, Hua; Wang, Jiafu; Pang, Yongqiang; Qu, Shaobo

    2015-06-01

    In this paper, the topology design of a lightweight ultra-broadband polarization-independent frequency selective surface absorber is proposed. The absorption over a wide frequency range of 6.68-26.08 GHz with reflection below -10 dB can be achieved by optimizing the topology and dimensions of the resistive frequency selective surface by virtue of genetic algorithm. This ultra-broadband absorption can be kept when the incident angle is less than 55 degrees and is independent of the incident wave polarization. The experimental results agree well with the numerical simulations. The density of our ultra-broadband absorber is only 0.35 g cm  -  3 and thus may find potential applications in microwave engineering, such as electromagnetic interference and stealth technology.

  17. Design and analysis of a shock absorber with variable moment of inertia for passive vehicle suspensions

    Science.gov (United States)

    Xu, Tongyi; Liang, Ming; Li, Chuan; Yang, Shuai

    2015-10-01

    A two-terminal mass (TTM) based vibration absorber with variable moment of inertia (VMI) for passive vehicle suspension is proposed. The VMI of the system is achieved by the motion of sliders embedded in a hydraulic driven flywheel. The moment of inertia increases in reaction to strong vertical vehicle oscillations and decreases for weak vertical oscillations. The hydraulic mechanism of the system converts the relative linear motion between the two terminals of the suspension into rotating motion of the flywheel. In the case of stronger vehicle vertical oscillation, the sliders inside the flywheel move away from the center of the flywheel because of the centrifugal force, hence yielding higher moment of inertia. The opposite is true in the case of weaker vehicle oscillation. As such, the moment of inertia adjusts itself adaptively in response to the road conditions. The performance of the proposed TTM-VMI absorber has been analyzed via dynamics modeling and simulation and further examined by experiments. In comparison to its counterpart with constant moment of inertia, the proposed VMI system offers faster response, better road handling and safety, improved ride comfort, and reduced suspension deflection except in the case of sinusoidal excitations.

  18. Delayed resonator with acceleration feedback - Complete stability analysis by spectral methods and vibration absorber design

    Science.gov (United States)

    Vyhlídal, Tomáš; Olgac, Nejat; Kučera, Vladimír

    2014-12-01

    This paper deals with the problem of active vibration suppression using the concept of delayed resonator (DR) absorber with acceleration feedback. A complete dynamic analysis of DR and its coupling with a single degree of freedom mechanical system are performed. Due to the presence of a delay in the acceleration feedback, the dynamics of the resonator itself, as well as the dynamics of combined system are of ‘neutral' character. On this system, spectral methods are applied to perform a complete stability analysis. Particularly, the method of cluster treatment of characteristic roots is used to determine stability boundaries in the space of the resonator parameters. Based on this analysis, a methodology to select the resonator parameters is proposed in order to guarantee desirable suppression characteristics and to provide safe stability margins. An example case study is included to demonstrate these analytical results.

  19. Design Parameters Analysis of Point Absorber WEC via an evolutionary-algorithm-based Dimensioning Tool

    Directory of Open Access Journals (Sweden)

    Marcos Blanco

    2015-10-01

    Full Text Available Wave energy conversion has an essential difference from other renewable energies since the dependence between the devices design and the energy resource is stronger. Dimensioning is therefore considered a key stage when a design project of Wave Energy Converters (WEC is undertaken. Location, WEC concept, Power Take-Off (PTO type, control strategy and hydrodynamic resonance considerations are some of the critical aspects to take into account to achieve a good performance. The paper proposes an automatic dimensioning methodology to be accomplished at the initial design project stages and the following elements are described to carry out the study: an optimization design algorithm, its objective functions and restrictions, a PTO model, as well as a procedure to evaluate the WEC energy production. After that, a parametric analysis is included considering different combinations of the key parameters previously introduced. A variety of study cases are analysed from the point of view of energy production for different design-parameters and all of them are compared with a reference case. Finally, a discussion is presented based on the results obtained, and some recommendations to face the WEC design stage are given.

  20. Design of Vibration Absorber using Spring and Rubber for Armored Vehicle 5.56 mm Caliber Rifle

    Directory of Open Access Journals (Sweden)

    Aditya Sukma Nugraha

    2014-12-01

    Full Text Available This paper presents a design of vibration absorber using spring and rubber for 5.56 mm caliber rifle armored vehicle. Such a rifle is used in a Remote-Controlled Weapon System (RCWS or a turret where it is fixed using a two degree of freedom pan-tilt mechanism. A half car lumped mass dynamic model of armored vehicles was derived. Numerical simulation was conducted using fourth order Runge Kutta method. Various types of vibration absorbers using spring and rubber with different configurations are installed in the elevation element. Vibration effects on horizontal direction, vertical direction and angular deviation of the elevation element was investigated. Three modes of fire were applied i.e. single fire, semi-automatic fire and automatic fire. From simulation results, it was concluded that the parallel configuration of damping rubber type 3, which has stiffness of 980,356.04 (N/m2 and damping coefficient of 107.37 (N.s/m, and Carbon steel spring whose stiffness coefficient is 5.547 x 106 (N/m2 provides the best vibration absorption. 

  1. A Deep Search For Faint Galaxies Associated With Very Low-redshift C IV Absorbers: II. Program Design, Absorption-line Measurements, and Absorber Statistics

    CERN Document Server

    Burchett, Joseph N; Prochaska, J Xavier; Werk, Jessica K; Tumlinson, Jason; O'Meara, John M; Bordoloi, Rongmon; Katz, Neal; Willmer, C N A

    2015-01-01

    To investigate the evolution of metal-enriched gas over recent cosmic epochs as well as to characterize the diffuse, ionized, metal-enriched circumgalactic medium (CGM), we have conducted a blind survey for C IV absorption systems in 89 QSO sightlines observed with the Hubble Space Telescope (HST) Cosmic Origins Spectrograph (COS). We have identified 42 absorbers at z < 0.16, comprising the largest uniform blind sample size to date in this redshift range. Our measurements indicate an increasing C IV absorber number density per comoving path length (dN/dX = 7.5 +/- 1.1) and modestly increasing mass density relative to the critical density of the Universe (Omega(C IV) = 10.0 +/- 1.5 x 10^-8 ) from z ~ 1.5 to the present epoch, consistent with predictions from cosmological hydrodynamical simulations. Furthermore, the data support a functional form for the column density distribution function that deviates from a single power-law, also consistent with independent theoretical predictions. As the data also probe...

  2. The case for using a sacrificial layer of absorbent insulation in the design of flat and low-sloped roofing

    Science.gov (United States)

    Stockton, Gregory R.

    2013-05-01

    Beginning about twenty-five years ago, there was a marked increase in the number of single-ply membrane roof designs used to cover and waterproof flat and low-sloped building roofs. Over the past ten years, there has been a substantial increase in the number of installations of white and more reflective single-ply roof systems, mostly using high density cellular foam insulation in the substrate for insulation. A major factor in the increase in the popularity of these highly insulated and more reflective roof systems is the fact that many governments began offering incentives for building owners to use reflective coverings and better insulated roofs. Now, owing to the energy efficient requirements for the design and construction of new buildings put forth in ASHRAE Standard 90.1, "Energy Standard for Buildings Except Low-Rise Residential Buildings" and the world's apparent desire to be "green" (or at least appear to be), more and more roof designs will include these reflective single-ply membranes, which use the cellular foam insulation boards to meet these requirements. Using a lower density traditional insulation will mean that the roof will have to be very thick to comply, increasing the costs of installation. High density cellular foams do not absorb water until time, vapor pressure drive, UV and thermal shock break down the foam and it becomes more absorbent. This could be 5-7 years or longer, depending on the roof construction and other factors. This means that any water that enters the roof through a breach (leak) in the membrane goes straight into the building. This is not a good consequence since the failure mode of any roof is water entering the building. Keeping the water out of the building is the purpose of the waterproofing layer. This paper reviews the techniques of moisture testing on building roofs and infrared (IR) thermography, and puts forth the idea and reasoning behind having a sacrificial layer of very absorbent insulation installed in every

  3. Optimization and Design of an Absorbance Spectrometer Controlled Using a Raspberry Pi to Improve Analytical Skills

    Science.gov (United States)

    Bougot-Robin, Kristelle; Paget, Jack; Atkins, Stephen C.; Edel, Joshua B.

    2016-01-01

    It is not uncommon for students to view laboratory instruments as black boxes. Unfortunately, this can often result in poor experimental results and interpretation. To tackle this issue, a laboratory course was designed to enable students not only to critically think about operating principles of the instrument but also to improve interpretation…

  4. Absorbable energy monitoring scheme: new design protocol to test vehicle structural crashworthiness

    OpenAIRE

    Ofochebe, Sunday M.; Enibe, Samuel O.; Ozoegwu, Chigbogu G.

    2016-01-01

    In vehicle crashworthiness design optimization detailed system evaluation capable of producing reliable results are basically achieved through high-order numerical computational (HNC) models such as the dynamic finite element model, mesh-free model etc. However the application of these models especially during optimization studies is basically challenged by their inherent high demand on computational resources, conditional stability of the solution process, and lack of knowledge of viable par...

  5. Analysis of mobile phone design features affecting radiofrequency power absorbed in a human head phantom.

    Science.gov (United States)

    Kuehn, Sven; Kelsh, Michael A; Kuster, Niels; Sheppard, Asher R; Shum, Mona

    2013-09-01

    The US FCC mandates the testing of all mobile phones to demonstrate compliance with the rule requiring that the peak spatial SAR does not exceed the limit of 1.6 W/kg averaged over any 1 g of tissue. These test data, measured in phantoms with mobile phones operating at maximum antenna input power, permitted us to evaluate the variation in SARs across mobile phone design factors such as shape and antenna design, communication technology, and test date (over a 7-year period). Descriptive statistical summaries calculated for 850 MHz and 1900 MHz phones and ANOVA were used to evaluate the influence of the foregoing factors on SARs. Service technology accounted for the greatest variability in compliance test SARs that ranged from AMPS (highest) to CDMA, iDEN, TDMA, and GSM (lowest). However, the dominant factor for SARs during use is the time-averaged antenna input power, which may be much less than the maximum power used in testing. This factor is largely defined by the communication system; e.g., the GSM phone average output can be higher than CDMA by a factor of 100. Phone shape, antenna type, and orientation of a phone were found to be significant but only on the order of up to a factor of 2 (3 dB). The SAR in the tilt position was significantly smaller than for touch. The side of the head did not affect SAR levels significantly. Among the remaining factors, external antennae produced greater SARs than internal ones, and brick and clamshell phones produced greater SARs than slide phones. Assuming phone design and usage patterns do not change significantly over time, we have developed a normalization procedure and formula that permits reliable prediction of the relative SAR between various communication systems. This approach can be applied to improve exposure assessment in epidemiological research.

  6. Design Considerations for an MEBT Chopper Absorber of 2.1 MeV H- at the Project X Injector Experiment at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Baffes, C.; Awida, M.; Chen, A.; Eidelman, Y.; Lebedev, V.; Prost, L.; Shemyakin, A.; Solyak, N.; Yakovlev, V.; /Fermilab

    2012-05-14

    The Project X Injector Experiment (PIXIE) will be a prototype of the Project X front end that will be used to validate the design concept and decrease technical risks. One of the most challenging components of PIXIE is the wide-band chopping system of the Medium Energy Beam Transport (MEBT) section, which will form an arbitrary bunch pattern from the initially CW 162.5 MHz 5mA beam. The present scenario assumes diverting 80% of the beam to an absorber to provide a beam with the average current of 1mA to SRF linac. This absorber must withstand a high level of energy deposition and high ion fluence, while being positioned in proximity of the superconductive cavities. This paper discusses design considerations for the absorber. Thermal and mechanical analyses of a conceptual design are presented, and future plans for the fabrication and testing of a prototype are described.

  7. Metamaterial Absorbers in Terahertz Band

    Institute of Scientific and Technical Information of China (English)

    Qi-Ye Wen; Huai-Wu Zhang; Qing-Hui Yang; Man-Man Mo

    2013-01-01

    In recent years, a great deal of effort has been made to a create terahertz (THz) wave absorber based on metamaterials (MM). Metamaterials absorbers have a variety of potential applications including thermal emitters, detector, stealth technology, phase imaging, etc. In this paper, we firstly introduce the basic structure and work principle of the THz MM absorbers, and a transmission line model is developed for devices analysis. To expand the application of THz absorbers, dual-band and broadband THz MM absorbers are designed, fabricated, and measured. At the end of this article, the future development trends of MM absorbers are discussed.

  8. Leveraging Understanding of Flow of Variable Complex Fluid to Design Better Absorbent Hygiene Products

    Science.gov (United States)

    Krautkramer, C.; Rend, R. R.

    2014-12-01

    Menstrual flow, which is a result of shedding of uterus endometrium, occurs periodically in sync with a women's hormonal cycle. Management of this flow while allowing women to pursue their normal daily lives is the purpose of many commercial products. Some of these products, e.g. feminine hygiene pads and tampons, utilize porous materials in achieving their goal. In this paper we will demonstrate different phenomena that have been observed in flow of menstrual fluid through these porous materials, share some of the advances made in experimental and analytical study of these phenomena, and also present some of the unsolved challenges and difficulties encountered while studying this kind of flow. Menstrual fluid is generally composed of four main components: blood plasma, blood cells, cervical mucus, and tissue debris. This non-homogeneous, multiphase fluid displays very complex rheological behavior, e. g., yield stress, thixotropy, and visco-elasticity, that varies throughout and between menstrual cycles and among women due to various factors. Flow rates are also highly variable during menstruation and across the population and the rheological properties of the fluid change during the flow into and through the product. In addition to these phenomena, changes to the structure of the porous medium within the product can also be seen due to fouling and/or swelling of the material. This paper will, also, share how the fluid components impact the flow and the consequences for computer simulation, the creation of a simulant fluid and testing methods, and for designing products that best meet consumer needs. We hope to bring to light the challenges of managing this complex flow to meet a basic need of women all over the world. An opportunity exists to apply learnings from research in other disciplines to improve the scientific knowledge related to the flow of this complex fluid through the porous medium that is a sanitary product.

  9. Absorbing Outflows in AGN

    Science.gov (United States)

    Mathur, Smita

    2002-01-01

    The goal of this program was a comprehensive multiwavelength study of absorption phenomena in active galactic nuclei (AGN). These include a variety of associated absorption systems: X-ray warm absorbers, X-ray cold absorbers. UV absorbers with high ionization lines, MgII absorbers, red quasars and BALQSOs. The aim is to determine the physical conditions in the absorbing outflows, study their inter-relations and their role in AGN. We designed several observing programs to achieve this goal: X-ray spectroscopy, UV spectroscopy, FLAY spectroscopy and X-ray imaging. We were very successful towards achieving the goal over the five year period as shown through following observing programs and papers. Copies of a few papers are attached with this report.

  10. The design, microstructure and tensile properties of B{sub 4}C particulate reinforced 6061Al neutron absorber composites

    Energy Technology Data Exchange (ETDEWEB)

    Chen, H.S. [School of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Wang, W.X., E-mail: Wangwenxian@tyut.edu.cn [School of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Li, Y.L.; Zhang, P. [School of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Nie, H.H. [Shanxi Coal-Mining Administrators College, Taiyuan 030024 (China); Wu, Q.C. [School of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China)

    2015-05-25

    Highlights: • B{sub 4}C/Al composites for neutron shielding were designed by MCNP program. • B{sub 4}C/Al composite were fabricated by vacuum hot pressing followed by hot rolling. • The properties can be enhanced by vacuum hot pressing followed by hot rolling. - Abstract: Based on the Monte Carlo Particle transport program MCNP, a novel boron carbide particulate reinforced 6061Al composite for neutron shielding (B{sub 4}C/6061Al NACs) with high strength and low density was designed. The NACs with four volume fractions (10%, 20%, 30% and 40%) were successfully fabricated by vacuum hot pressing followed by hot rolling (VPHR) in atmospheric environments. The calculation results indicated that the neutron transmission ratio decreased with the increasing of B{sub 4}C content and the thickness of plates. B{sub 4}C particle is uniformly distributed in the matrix, exhibiting the good bonding in interface. The phases of neutron absorbers were mainly B{sub 4}C and Al, and a spot of AlB{sub 2} and Al{sub 3}BC. The grain of the matrix was refined and the dislocation was formed around the particles. With increasing the B{sub 4}C content, the particles gathered, breakage appeared, and the tensile strength of composite first increased and then decreased. The failure mode of B{sub 4}C/6061Al NACs included: the interfacial debonding and the cleavage fracture of particles.

  11. Design and Application of Indoor Space Sound Absorber%室内空间吸声体的设计与应用

    Institute of Scientific and Technical Information of China (English)

    宋煜锟; 李鹏

    2015-01-01

    介绍了室内声环境设计用空间吸声体的材料和结构,讨论了空间吸声体与绿植、照明、造型、文化等因素相结合的创意设计手法,以及空间吸声体在不同抽象空间的导向作用,并总结了空间吸声体广泛应用到室内艺术设计中的必要条件和发展方向。同时,以实例显示空间吸声体别致多样的造型,及其所显现的丰富的室内艺术效果。%The paper introduces space sound absorber with its materials and structures inthe indoor sound environment design. It discusses the design methods that combining the spatial sound absorber and other elements like green plant, lighting, modeling and cultural factors, and the guiding function of the absorber in different abstract spaces. With the introduction, the requirements of the application of space sound absorber in indoor art design and its development trend is concluded. Meanwhile, the paper shows a number of examples of the absorber in different styles and the abundant artistic effect of them in the indoor environment.

  12. Design, preparation and microwave absorbing properties of resin matrix composites reinforced by SiC fibers with different electrical properties

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Haitao, E-mail: xzddlht@163.com [Science and Technology on Advanced Ceramic Fibers and Composites Laboratory, College of Aerospace Science and Engineering, National University of Defense Technology, Changsha 410073 (China); Science and Technology on Scramjet Laboratory, College of Aerospace Science and Engineering, National University of Defense Technology, Changsha 410073 (China); Cheng, Haifeng; Tian, Hao [Science and Technology on Advanced Ceramic Fibers and Composites Laboratory, College of Aerospace Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

    2014-01-15

    Highlights: • SSMASs have better microwave absorbing properties in smaller thickness. • SSMASs can be realized by SiC fibers with different electrical resistivity. • Resistivity of SiC fibers can be regulated by adjusting surface characteristics. • The bandwidth of SSMASs at reflectivity below −10 dB can reach 11.6 GHz. -- Abstract: One kind of sandwich structure microwave absorbing structures (SSMASs) derived from Salisbury absorbers is reported. The impedance characteristics of SSMASs are analyzed, and the mechanisms of broadening microwave absorbing bandwidth are interpreted by Smith chart. In order to realize SSMASs, high electrical resistivity SiC fibers with Si–C–O surface layers and low electrical resistivity SiC fibers with pyrocarbon surface layers are employed and analyzed by SEM, XPS, AES and HRTEM. The conductive model of SiC fibers with pyrocarbon layers is built and electrical resistivity simulation is done. The SSMASs are fabricated by employing plain woven SiC fiber fabrics with high and low electrical resistivity as reinforcements of dielectric layers and lossy layer, respectively. The microwave absorbing properties of SSMASs are measured and compared with simulated results. The results show that the experimental and simulated results are in good agreement, the SSMASs have better wideband microwave absorbing properties, and the microwave absorbing bandwidth at reflectivity below −10 dB can reach 11.6 GHz.

  13. Design and Development of Expanded Graphite-Based Non-metallic and Flexible Metamaterial Absorber for X-band Applications

    Science.gov (United States)

    Borah, Dipangkar; Bhattacharyya, Nidhi S.

    2016-09-01

    The possibility of using expanded graphite instead of a metallic layer as unit cells and ground planes for metamaterial absorbers in X-band is investigated. A metamaterial absorber was fabricated on a flexible linear low-density polyethylene substrate using an expanded graphite-based circular ring as the unit cell structure. The unit cell was simulated and optimized for which the metamaterial absorber exhibited 98.9% absorption at 11.22 GHz. The fabricated expanded graphite-based absorber showed a reflection loss of -24.51 dB at 11.56 GHz with -10 dB bandwidth of 0.39 GHz (3.37%). The performance of the same structure with copper was also measured. The expanded graphite-based metamaterial absorber showed enhanced performance as compared to the copper-based metamaterial absorber. The width of the ring was varied to tune the reflection loss. The proposed expanded graphite-based metamaterial absorber possesses the advantages of being ultra-thin, flexible and non-corrosive.

  14. Implementation of strength pareto evolutionary algorithm II in the multiobjective burnable poison placement optimization of KWU pressurized water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Gharari, Rahman [Nuclear Science and Technology Research Institute (NSTRI), Tehran (Iran, Islamic Republic of); Poursalehi, Navid; Abbasi, Mohmmadreza; Aghale, Mahdi [Nuclear Engineering Dept, Shahid Beheshti University, Tehran (Iran, Islamic Republic of)

    2016-10-15

    In this research, for the first time, a new optimization method, i.e., strength Pareto evolutionary algorithm II (SPEA-II), is developed for the burnable poison placement (BPP) optimization of a nuclear reactor core. In the BPP problem, an optimized placement map of fuel assemblies with burnable poison is searched for a given core loading pattern according to defined objectives. In this work, SPEA-II coupled with a nodal expansion code is used for solving the BPP problem of Kraftwerk Union AG (KWU) pressurized water reactor. Our optimization goal for the BPP is to achieve a greater multiplication factor (K-e-f-f) for gaining possible longer operation cycles along with more flattening of fuel assembly relative power distribution, considering a safety constraint on the radial power peaking factor. For appraising the proposed methodology, the basic approach, i.e., SPEA, is also developed in order to compare obtained results. In general, results reveal the acceptance performance and high strength of SPEA, particularly its new version, i.e., SPEA-II, in achieving a semioptimized loading pattern for the BPP optimization of KWU pressurized water reactor.

  15. Design and Control of the PowerTake-Off System for a Wave Energy Converter with Multiple Absorbers

    DEFF Research Database (Denmark)

    Hansen, Rico Hjerm

    feasibility for real PTO systems still causes dispute. In this dissertation an analytical result is provided, proving that reactive control is highly beneficial at even “low” PTO efficiencies. The formulated reactive control is tested in a wave tank with 1:20 scale absorbers, validating the expected...... performance. The wave tank tests also verify the derived wave and absorber models, which are based on linear wave theory. This increases the confidence in the heavy use of models through-out the work. A new high performing control method is developed for wave power extraction characterised...... force control of a multi-chambered cylinder driven by the absorber, while efficiently transferring the generated power directly into a battery of high pressure accumulators. The concept allows DDCs of multiple absorbers to supply the same accumulator battery, where a hydraulic motor may use the stored...

  16. Sensing with THz metamaterial absorbers

    CERN Document Server

    Cong, Longqing

    2014-01-01

    Metamaterial perfect absorbers from microwaves to optical part of the electromagnetic spectrum has been intensely studied for its ability to absorb electromagnetic radiation. Perfect absorption of light by metamaterials have opened up new opportunities for application oriented functionalities such as efficient sensors and emitters. We present an absorber based sensing scheme at the terahertz frequencies and discuss optimized designs to achieve high frequency and amplitude sensitivities. The major advantage of a perfect metamaterial absorber as a sensor is the sensitive shift in the absorber resonance frequency along with the sharp change in the amplitude of the resonance due to strong interaction of the analyte with the electric and the magnetic fields at resonant perfect absorption frequency. We compare the sensing performance of the perfect metamaterial absorber with its complementary structural design and planar metasurface with identical structure. The best FoM values obtained for the absorber sensor here...

  17. Multiband terahertz metamaterial absorber

    Institute of Scientific and Technical Information of China (English)

    Gu Chao; Qu Shao-Bo; Pei Zhi-Bin; Xu Zhuo; Liu Jia; Gu Wei

    2011-01-01

    This paper reports the design of a multiband metamaterial (MM) absorber in the terahertz region. Theoretical and simulated results show that the absorber has four distinct and strong absorption points at 1.69, 2.76, 3.41 and that the impedance of MM could be tuned to match approximately the impedance of the free space to minimise the reflectance at absorption frequencies and large power loss exists at absorption frequencies. The distribution of the power loss indicates that the absorber is an excellent electromagnetic wave collector: the wave is first trapped and reinforced in certain specific locations and then consumed. This multiband absorber has applications in the detection of explosives and materials characterisation.

  18. Preliminary Evaluation of Alternate Designs for HFIR Low-Enriched Uranium Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Renfro, David G [ORNL; Chandler, David [ORNL; Cook, David Howard [ORNL; Ilas, Germina [ORNL; Jain, Prashant K [ORNL; Valentine, Jennifer R [ORNL

    2014-11-01

    Engineering design studies of the feasibility of conversion of the High Flux Isotope Reactor (HFIR) from high-enriched uranium (HEU) to low-enriched uranium (LEU) fuel are ongoing at Oak Ridge National Laboratory (ORNL) as part of an effort sponsored by the U.S. Department of Energy s Global Threat Reduction Initiative (GTRI)/Reduced Enrichment for Research and Test Reactors (RERTR) program. The fuel type selected by the program for the conversion of the five high-power research reactors in the U.S. that still use HEU fuel is a new U-Mo monolithic fuel. Studies by ORNL have previously indicated that HFIR can be successfully converted using the new fuel provided (1) the reactor power can be increased from 85 MW to 100 MW and (2) the fuel can be fabricated to a specific reference design. Fabrication techniques for the new fuel are under development by the program but are still immature, especially for the complex aspects of the HFIR fuel design. In FY 2012, the program underwent a major shift in focus to emphasize developing and qualifying processes for the fabrication of reliable and affordable LEU fuel. In support of this new focus and in an effort to ensure that the HFIR fuel design is as suitable for reliable fabrication as possible, ORNL undertook the present study to propose and evaluate several alternative design features. These features include (1) eliminating the fuel zone axial contouring in the previous reference design by substituting a permanent neutron absorber in the lower unfueled region of all of the fuel plates, (2) relocating the burnable neutron absorber from the fuel plates of the inner fuel element to the side plates of the inner fuel element (the fuel plates of the outer fuel element do not contain a burnable absorber), (3) relocating the fuel zone inside the fuel plate to be centered on the centerline of the depth of the plate, and (4) reshaping the radial contour of the relocated fuel zone to be symmetric about this centerline. The present

  19. Preliminary Evaluation of Alternate Designs for HFIR Low-Enriched Uranium Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Renfro, David [ORNL; Chandler, David [ORNL; Cook, David [ORNL; Ilas, Germina [ORNL; Jain, Prashant [ORNL; Valentine, Jennifer [ORNL

    2014-10-30

    Engineering design studies of the feasibility of conversion of the High Flux Isotope Reactor (HFIR) from high-enriched uranium (HEU) to low-enriched uranium (LEU) fuel are ongoing at Oak Ridge National Laboratory (ORNL) as part of an effort sponsored by the U.S. Department of Energy’s Global Threat Reduction Initiative (GTRI)/Reduced Enrichment for Research and Test Reactors (RERTR) program. The fuel type selected by the program for the conversion of the five high-power research reactors in the U.S. that still use HEU fuel is a new U-Mo monolithic fuel. Studies by ORNL have previously indicated that HFIR can be successfully converted using the new fuel provided (1) the reactor power can be increased from 85 MW to 100 MW and (2) the fuel can be fabricated to a specific reference design. Fabrication techniques for the new fuel are under development by the program but are still immature, especially for the “complex” aspects of the HFIR fuel design. In FY 2012, the program underwent a major shift in focus to emphasize developing and qualifying processes for the fabrication of reliable and affordable LEU fuel. In support of this new focus and in an effort to ensure that the HFIR fuel design is as suitable for reliable fabrication as possible, ORNL undertook the present study to propose and evaluate several alternative design features. These features include (1) eliminating the fuel zone axial contouring in the previous reference design by substituting a permanent neutron absorber in the lower unfueled region of all of the fuel plates, (2) relocating the burnable neutron absorber from the fuel plates of the inner fuel element to the side plates of the inner fuel element (the fuel plates of the outer fuel element do not contain a burnable absorber), (3) relocating the fuel zone inside the fuel plate to be centered on the centerline of the depth of the plate, and (4) reshaping the radial contour of the relocated fuel zone to be symmetric about this centerline. The

  20. 阻尼可调减振器外特性的设计%Design of External Characteristics of Adjustable Damping Shock Absorber

    Institute of Scientific and Technical Information of China (English)

    王勋; 陈思忠

    2009-01-01

    针对可变串联阻尼孔减振器外特性的特点,提出了其主要参数的设计方法. 建立了整车7自由度数学模型,以提高整车的瞬态响应特性、平顺性、车轮接地性为目的,对某越野车的串联阻尼孔可调减振器外特性进行了设计. 结果表明,采用串联阻尼孔可调减振器的越野车辆,其在不同的路面上均有良好的操纵稳定性和平顺性,越野车速也有所提高.%According to the features of external characteristics of shock absorber whose series orifice is variable, a design approach of its key parameters is put forward. A mathematical vehicle model of a seven-freedom was built up and solved in order to design the key parameters of shock absorber whose series orifice is changeable. The purpose to optimize external characteristics of shock absorber is to improve the transient response characteristic, riding and wheel ground adhesion index. The results indicated that using such a kind of shock absorber, the stability and comfort of off-road vehicles are acceptable, and the speed on rough road is increased.

  1. Research Progress on Structural Design of Polymer Matrix Microwave Absorbing Materials%聚合物基吸波材料结构设计研究进展

    Institute of Scientific and Technical Information of China (English)

    段磊; 温变英

    2014-01-01

    The distribution characteristics and types of present absorbents in polymer matrix were introduced. Comparing with the structure of single layer polymer matrix microwave absorbing materials,the design principle of pyramidal, double layer and multi layer of polymer matrix microwave absorbing materials was emphasized. The structure feature and research progress on pyramidal and layer structure of polymer matrix microwave absorbing materials were reviewed, and future development trends was also presented.%介绍了目前吸收剂在聚合物基体中的分布特点和类型,通过与单层聚合物基吸波材料的结构对比,重点阐述了聚合物基吸波材料角锥、双层、多层结构的设计原理。同时对聚合物基吸波材料的角锥和层状结构特征与研究进展进行了综述,并对其发展方向提出了展望。

  2. Design and Experimental Implementation of a Beam-Type Twin Dynamic Vibration Absorber for a Cantilevered Flexible Structure Carrying an Unbalanced Rotor: Numerical and Experimental Observations

    Directory of Open Access Journals (Sweden)

    Abdullah Özer

    2015-01-01

    Full Text Available This paper presents experimental and numerical results about the effectiveness of a beam-type twin dynamic vibration absorber for a cantilevered flexible structure carrying an unbalanced rotor. An experimental laboratory prototype setup has been built and implemented in our laboratory and numerical investigations have been performed through finite element analysis. The proposed system design consists of a primary cantilevered flexible structure with an attached dual-mass cantilevered secondary dynamic vibration absorber arrangement. In addition, an unbalanced rotor system is attached to the tip of the flexible cantilevered structure to inspect the system response under harmonic excitations. Numerical findings and experimental observations have revealed that significant vibration reductions are possible with the proposed dual-mass, cantilevered dynamic vibration absorber on a flexible cantilevered platform carrying an unbalanced rotor system at its tip. The proposed system is efficient and it can be practically tuned for variety of design and operating conditions. The designed setup and the results in this paper can serve for practicing engineers, researchers and can be used for educational purposes.

  3. 多层微波吸收材料的遗传算法设计%Design of multilayer microwave absorbing material based on Genetic Algorithm

    Institute of Scientific and Technical Information of China (English)

    张丹枫; 张敏; 曾国勋; 吴子秋

    2013-01-01

    利用遗传算法(GA)编写多涂层优化设计程序,该程序可以调用矢量网络分析仪测量的电磁参数,根据吸波材料的电磁参数对0.5~6.0 GHz范围内不同材料的涂层厚度进行优化设计;讨论了不同的目标函数和厚度优化方法对优化结果的影响,提出多常数权重法建立目标函数.结果表明:此方法可以简单地从材料电磁参数的数据库中,按照设定的要求计算得到最优的电磁波吸收涂层;利用提出的多常数权重法建立的目标函数可以更好的设计宽频带高吸收的电磁波吸收涂层.%An optimum designing program of multilayer absorbing material is compiled based on Genetic Algorithm (GA). The program transfers the electromagnetic parameters which measured by vector network analyzer, and can process thickness optimum design of different absorbing materials in the range of 0.5-6.0 GHz. The results show that the best absorbing layers can be easily gained from the electromagnetic parameter database by computing with this program according to the requirement. The multi-constant weight method is very helpful to design the microwave absorbing layers of broad-frequency and high absorption.

  4. Design and Implementation of a High-Voltage Generator with Output Voltage Control for Vehicle ER Shock-Absorber Applications

    Directory of Open Access Journals (Sweden)

    Chih-Lung Shen

    2013-01-01

    Full Text Available A self-oscillating high-voltage generator is proposed to supply voltage for a suspension system in order to control the damping force of an electrorheological (ER fluid shock absorber. By controlling the output voltage level of the generator, the damping force in the ER fluid shock absorber can be adjusted immediately. The shock absorber is part of the suspension system. The high-voltage generator drives a power transistor based on self-excited oscillation, which converts dc to ac. A high-frequency transformer with high turns ratio is used to increase the voltage. In addition, the system uses the car battery as dc power supply. By regulating the duty cycle of the main switch in the buck converter, the output voltage of the buck converter can be linearly adjusted so as to obtain a specific high voltage for ER. The driving system is self-excited; that is, no additional external driving circuit is required. Thus, it reduces cost and simplifies system structure. A prototype version of the actual product is studied to measure and evaluate the key waveforms. The feasibility of the proposed system is verified based on experimental results.

  5. Metasurface Broadband Solar Absorber

    CERN Document Server

    Azad, A K; Sykora, M; Weisse-Bernstein, N R; Luk, T S; Taylor, A J; Dalvit, D A R; Chen, H -T

    2015-01-01

    We demonstrate a broadband, polarization independent, omnidirectional absorber based on a metallic metasurface architecture, which accomplishes greater than 90% absorptance in the visible and near-infrared range of the solar spectrum, and exhibits low emissivity at mid- and far-infrared wavelengths. The complex unit cell of the metasurface solar absorber consists of eight pairs of gold nano-resonators that are separated from a gold ground plane by a thin silicon dioxide spacer. Our experimental measurements reveal high-performance absorption over a wide range of incidence angles for both s- and p-polarizations. We also investigate numerically the frequency-dependent field and current distributions to elucidate how the absorption occurs within the metasurface structure. Furthermore, we discuss the potential use of our metasurface absorber design in solar thermophotovoltaics by exploiting refractory plasmonic materials.

  6. Unidirectional perfect absorber

    Science.gov (United States)

    Jin, L.; Wang, P.; Song, Z.

    2016-09-01

    This study proposes a unidirectional perfect absorber (UPA), which we realized with a two-arm Aharonov-Bohm interferometer, that consists of a dissipative resonator side-coupled to a uniform resonator array. The UPA has reflection-less full absorption on one direction, and reflectionless full transmission on the other, with an appropriate magnetic flux and coupling, detuning, and loss of the side-coupled resonator. The magnetic flux controls the transmission, the left transmission is larger for magnetic flux less than one-half flux quantum; and the right transmission is larger for magnetic flux between one-half and one flux quantum. Besides, a perfect absorber (PA) can be realized based on the UPA, in which light waves from both sides, with arbitrary superposition of the ampli- tude and phase, are perfectly absorbed. The UPA is expected to be useful in the design of novel optical devices.

  7. 电涡流耗能动力吸振器设计与试验研究%Eddy Current Vibration Absorber Design and Experiments

    Institute of Scientific and Technical Information of China (English)

    李斌; 牛文超; 徐兆懿

    2016-01-01

    针对飞机垂尾抖振抑制的需要,提出一种空间布局紧凑、基于非接触式电涡流耗能机理、阻尼可设计的动力吸振器设计方案。电涡流耗能机制的引入保证该动力吸振器具有良好的环境适应性、耐久性和可靠性。基于电磁场理论,建立了电涡流阻尼力的计算模型,获得电磁阻尼的设计规律,通过与试验结果对比,验证了电涡流阻尼模型的准确性。并以等效悬臂梁结构为对象,应用最优参数设计原理确定动力吸振器参数,设计制造了动力吸振器样机。试验结果表明,该电涡流动力吸振器具有良好的吸振性能,最大减幅比可达98%。%Aiming at the need of vertical tail buffet suppression, a design scheme of dynamic vibration absorber with compact layout and adjustable damping is proposed; this is based on the mechanism of eddy current energy dissipation. Eddy current energy dissipation can ensure that the dynamic vibration absorber has good environmental adaptability, durability and reliability. Based on the electromagnetic theory, the calculation model of eddy current damping force is established and the design rule of eddy damping force is concluded. Through the comparison be⁃tween the calculations and the experiments, the validation and accuracy of eddy current damping force model are verified. Taking an equivalent cantilever beam system as the object of vibration control, and on the basis of the the⁃ory of dynamic vibration absorber optimal design, we determined the optimal parameters of dynamic vibration ab⁃sorber and completed the design and manufacture of eddy current dynamic vibration absorber prototype. Experimen⁃tal results show that the maximum amplitude of cantilever beam can be decreased at most by 98%, and the pro⁃posed eddy current dynamic vibration absorber has obvious vibration-absorption effect.

  8. Improvement Of The Helmholtz Absorber

    Science.gov (United States)

    Morrow, Duane L.

    1992-01-01

    Helmholtz-resonator system improved to enable it to absorb sound at more than one frequency without appreciable loss of effectiveness at primary frequency. Addition of annular cavities enables absorption of sound at harmonic frequencies in addition to primary frequency. Improved absorber designed for use on structures of high transmission loss. Applied to such machines as fixed-speed engines and fans.

  9. Universal metamaterial absorbe

    CERN Document Server

    Smaali, Rafik; Moreau, Antoine; Taliercio, Thierry; Centeno, Emmanuel

    2016-01-01

    We propose a design for an universal absorber, characterized by a resonance frequency that can be tuned from visible to microwave frequencies independently of the choice of the metal and the dielectrics involved. An almost resonant perfect absorption up to 99.8 % is demonstrated at resonance for all polarization states of light and for a very wide angular aperture. These properties originate from a magnetic Fabry-Perot mode that is confined in a dielectric spacer of $\\lambda/100$ thickness by a metamaterial layer and a mirror. An extraordinary large funneling through nano-slits explains how light can be trapped in the structure. Simple scaling laws can be used as a recipe to design ultra-thin perfect absorbers whatever the materials and the desired resonance wavelength, making our design truly universal.

  10. Optimization of the design of extremely thin absorber solar cells based on electrodeposited ZnO nanowires.

    Science.gov (United States)

    Lévy-Clément, Claude; Elias, Jamil

    2013-07-22

    The properties of the components of ZnO/CdSe/CuSCN extremely thin absorber (ETA) solar cells based on electrodeposited ZnO nanowires (NWs) were investigated. The goal was to study the influence of their morphology on the characteristics of the solar cells. To increase the energy conversion efficiency of the solar cell, it was generally proposed to increase the roughness factor of the ZnO NW arrays (i.e. to increase the NW length) with the purpose of decreasing the absorber thickness, improving the light scattering, and consequently the light absorption in the ZnO/CdSe NW arrays. However, this strategy increased the recombination centers, which affected the efficiency of the solar cell. We developed another strategy that acts on the optical configuration of the solar cells by increasing the diameter of the ZnO NW (from 100 to 330 nm) while maintaining a low roughness factor. We observed that the scattering of the ZnO NW arrays occurred over a large wavelength range and extended closer to the CdSe absorber bandgap, and this led to an enhancement in the effective absorption of the ZnO/CdSe NW arrays and an increase in the solar cell characteristics. We found that the thicknesses of CuSCN above the ZnO/CdSe NW tips and the CdSe coating layer were optimized at 1.5 μm and 30 nm, respectively. Optimized ZnO/CdSe/CuSCN solar cells exhibiting 3.2% solar energy conversion efficiency were obtained by using 230 nm diameter ZnO NWs.

  11. Optimal Sound Absorbing Structures

    CERN Document Server

    Yang, Min; Fu, Caixing; Sheng, Ping

    2016-01-01

    Causal nature of the acoustic response, for any materials or structures, dictates an inequality that relates the absorption spectrum of the sample to its thickness. We present a general recipe for constructing sound-absorbing structures that can attain near-equality for the causal relation with very high absorption performance; such structures are denoted optimal. Our strategy involves using carefully designed acoustic metamaterials as backing to a thin layer of conventional sound absorbing material, e.g., acoustic sponge. By using this design approach, we have realized a 12 cm-thick structure that exhibits broadband, near-perfect flat absorption spectrum starting at around 400 Hz. From the causal relation, the calculated minimum sample thickness is 11.5 cm for the observed absorption spectrum. We present the theory that underlies such absorption performance, involving the evanescent waves and their interaction with a dissipative medium, and show the excellent agreement with the experiment.

  12. The Flexible Bass Absorber

    DEFF Research Database (Denmark)

    Adelman-Larsen, Niels Werner; Thompson, Eric Robert; Gade, Anders Christian

    2007-01-01

    Multi-purpose concert halls face a dilemma. They host different performance types that require significantly different acoustic conditions in order to provide the best sound quality to both the performers, sound engineers and the audience. Pop and rock music often contains high levels of bass sou...... has been developed. Measurements were made on a variable and mobile low-frequency absorber. The paper presents the results of prototype sound absorption measurements as well as elements of the design....

  13. The Flexible Bass Absorber

    DEFF Research Database (Denmark)

    Adelman-Larsen, Niels Werner; Thompson, Eric Robert; Gade, Anders Christian

    2007-01-01

    Multi-purpose concert halls face a dilemma. They host different performance types that require significantly different acoustic conditions in order to provide the best sound quality to both the performers, sound engineers and the audience. Pop and rock music often contain high levels of bass soun...... has been developed. Measurements were made on a variable and mobile low-frequency absorber. The paper presents the results of prototype sound absorption measurements as well as elements of the design....

  14. Effect of Burnable Absorbers on Inert Matrix Fuel Performance and Transuranic Burnup in a Low Power Density Light-Water Reactor

    Directory of Open Access Journals (Sweden)

    Geoff Recktenwald

    2013-04-01

    Full Text Available Zirconium dioxide has received particular attention as a fuel matrix because of its ability to form a solid solution with transuranic elements, natural radiation stability and desirable mechanical properties. However, zirconium dioxide has a lower coefficient of thermal conductivity than uranium dioxide and this presents an obstacle to the deployment of these fuels in commercial reactors. Here we show that axial doping of a zirconium dioxide based fuel with erbium reduces power peaking and fuel temperature. Full core simulations of a modified AP1000 core were done using MCNPX 2.7.0. The inert matrix fuel contained 15 w/o transuranics at its beginning of life and constituted 28% of the assemblies in the core. Axial doping reduced power peaking at startup by more than ~23% in the axial direction and reduced the peak to average power within the core from 1.80 to 1.44. The core was able to remain critical between refueling while running at a simulated 2000 MWth on an 18 month refueling cycle. The results show that the reactor would maintain negative core average reactivity and void coefficients during operation. This type of fuel cycle would reduce the overall production of transuranics in a pressurized water reactor by 86%.

  15. 航空小型轴套式橡胶隔振器的设计%Designing of the Small Sleeve Rubber Absorber for Aviation

    Institute of Scientific and Technical Information of China (English)

    何林涛; 冷献春; 任建峰

    2014-01-01

    从被动隔振的基本原理出发,探讨了航空电子器件隔振的设计原则,总结了一种航空小型轴套式橡胶隔振器的设计方法,并且通过试验证明了方法的可行性。%Based on principle of the passive shock absorption,this paper discusses the desig-ning principia of the shock absorption for aero elec-tro component,and summarizes the designing method for the small rubber absorber.At last,the tests were indicated that the method has reliabili-ty.

  16. Synchrotron radiation absorber for high density loads

    Science.gov (United States)

    Anashin, V. V.; Kuzminych, V. S.; Trakhtenberg, E. M.; Zholents, A. A.

    1991-10-01

    A design of a special synchrotron radiation absorber for the storage ring VEPP-4M is presented. The density of the synchrotron radiation power on the absorber surface is up to 500 W/mm 2. The absorber is made from a beryllium plate, brazed inside to the copper vacuum chamber, which is intensively water-cooled from outside.

  17. A polarization-independent broadband terahertz absorber

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Cheng; Zang, XiaoFei, E-mail: xfzang@usst.edu.cn, E-mail: ymzhu@usst.edu.cn; Wang, YiQiao; Chen, Lin; Cai, Bin; Zhu, YiMing, E-mail: xfzang@usst.edu.cn, E-mail: ymzhu@usst.edu.cn [Shanghai Key Laboratory of Modern Optical System and Engineering Research Center of Optical Instrument and System, Ministry of Education, University of Shanghai for Science and Technology, Shanghai 200093 (China)

    2014-07-21

    A highly efficient broadband terahertz absorber is designed, fabricated, and experimentally as well as theoretically evaluated. The absorber comprises a heavily doped silicon substrate and a well-designed two-dimensional grating. Due to the destructive interference of waves and diffraction, the absorber can achieve over 95% absorption in a broad frequency range from 1 to 2 THz and for angles of incidence from 0° to 60°. Such a terahertz absorber is also polarization-independent due to its symmetrical structure. This omnidirectional and broadband absorber have potential applications in anti-reflection coatings, imaging systems, and so on.

  18. Test Facility for Volumetric Absorber

    Energy Technology Data Exchange (ETDEWEB)

    Ebert, M.; Dibowski, G.; Pfander, M.; Sack, J. P.; Schwarzbozl, P.; Ulmer, S.

    2006-07-01

    Long-time testing of volumetric absorber modules is an inevitable measure to gain the experience and reliability required for the commercialization of the open volumetric receiver technology. While solar tower test facilities are necessary for performance measurements of complete volumetric receivers, the long-term stability of individual components can be tested in less expensive test setups. For the qualification of the aging effects of operating cycles on single elements of new absorber materials and designs, a test facility was developed and constructed in the framework of the KOSMOSOL project. In order to provide the concentrated solar radiation level, the absorber test facility is integrated into a parabolic dish system at the Plataforma Solar de Almeria (PSA) in Spain. Several new designs of ceramic absorbers were developed and tested during the last months. (Author)

  19. Design of Multiple Dynamic Vibration Absorbers for Buffet Control of Vertical Tails%垂尾抖振控制中多重动力吸振器设计

    Institute of Scientific and Technical Information of China (English)

    牛文超; 李斌

    2016-01-01

    Aiming at the need of vertical tail buffet suppression, the eddy current vibration absorber is designed and its parameters is introduced. The optimal design parameters method of the multiple dynamic vibration absorber is deduced to realize the vibration absorber miniaturization. Taking an equivalent cantilever beam system and a scaled vertical tail as the objects respectively for vibration control, considering the actual size of the vibration absorber and the vertical tail, and choosing the reasonable installation position, the vibration absorption effect of the multiple-dynamic-vibration-absorber is verified through the finite element simulation. Simulation results show that the vibration suppression property of the multiple-dynamic-vibration-absorber scheme is very good. Compared to the single large dynamic vibration absorber, the vibration attenuation rate of the quadruple dynamic vibration absorber scheme is increased by 16%, and will be raised by 20%for the ten-dynamic-vibration-absorber scheme.%针对飞机垂尾抖振抑制的需要,进行小型电涡流耗能动力吸振器设计,并推导多重动力吸振器最优参数设计方法。分别以悬臂梁系统和缩比垂尾为被控对象,并考虑动力吸振器与垂尾实际尺寸,选定合理安装位置,通过有限元仿真验证多重动力吸振器吸振性能,仿真结果表明多重动力吸振器具有良好的振动抑制效果,可满足设计预期要求。

  20. Gd/sub 2/O/sub 3/ up to 9 weight percent, an established burnable poison for advanced fuel management in pressurized water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Boehm, W.; Kiehlmann, H.D.; Neufert, A.; Peehs, M.

    1987-07-01

    High weight percent Gd/sub 2/O/sub 3/ has given excellent results when applied as burnable poison in pressurized water reactors for advanced fuel management tasks. Poisoning of up to 9 weight% Gd/sub 2/O/sub 3/ has been implemented in commercial reload cores to match the requirements of full low leakage loading and cycle extension strategies. Operational performance has confirmed that the high degree of accuracy achieved for calculational methods for standard loading applications also applies for highly Gd poisoned cores. The UO/sub 2/-Gd/sub 2/O/sub 3/ fabrication process has been rationalized by the use of direct pelletizing.

  1. Advanced PWR in-core fuel management with optimized gadolinia fuel designs

    Energy Technology Data Exchange (ETDEWEB)

    Berger, H.D.; Neufert, A. [Siemens AG / Power Generation KWU, Nuclear Fuel Cycle, Erlangen (Germany)

    1999-07-01

    Utilities operating LWRs require fuel assemblies and in-core fuel management service, which ensure safe, flexible and cost-effective production of electricity. With the reliability of the fuel having been always the most important requirement, advanced measures to minimize fuel cycle costs are receiving increasing attention in the light of the pressure on costs within the de-regulated power generation markets. The role of in-core fuel management in supporting the goal to minimize fuel cycle costs consists in the development of more demanding core loading strategies, i.e. in the first place more advanced low leakage loading patterns. A prerequisite for this type of loading pattern is the use of an optimized burnable absorber design. Gadolinia as integrated burnable absorber is a very effective means for limiting the critical boron concentration and power peaking factors. Siemens has accumulated extensive experience with Gd-fuel for almost 20 years with e.g. more than 5500 Gd-FA's delivered for PWRs and irradiated up to 65 MWd/kg{sub HM}. Current development efforts for optimizing Gd-fuel are focused on the reduction of the inherent penalties of today's Gd-Fa designs, i.e. reduced average FA enrichment and heavy metal content as well as residual reactivity binding. The most effective way to overcome these drawbacks is the reduction of the Gd{sub 2}O{sub 3} concentration to values of approximately 2 w/o, for which according to recent measurements of the heat conductivity of modern Gd-fuels the reduction of the fissile content in the Gd-rods is no longer necessary. Various feasibility studies have been performed to evaluate the consequences of low-Gd designs for both Siemens PWRs and Non-Siemens PWRs, for which more restrictive boundary conditions with respect to critical boron concentration and peaking factors have to be fulfilled. These studies as well as the first realization of an extended reactor cycle using a low Gd-Fa reload design confirm that the in

  2. Laboratory differential simulation design method of pressure absorbers for carbonization of phenolate solution by carbon dioxide in coal-tar processing

    Energy Technology Data Exchange (ETDEWEB)

    Linek, V.; Sinkule, J.; Moucha, T.; Rejl, J.F. [Prague Institute for Chemical Technology, Prague (Czech Republic). Dept. of Chemical Engineering

    2009-01-15

    A laboratory differential simulation method is used for the design of carbonization columns at coal-tar processing in which phenols are regenerated from phenolate solution by carbon dioxide absorption. The design method is based on integration of local absorption rates of carbon dioxide along the column. The local absorption rates into industrial phenolate mixture are measured in a laboratory model contactor for various compositions of the gas and liquid phases under the conditions that ensure the absorption rates in the laboratory absorber simulate the local rates in the industrial column. On the bases of the calculations, two-step carbonization columns were designed for 30000 t/year of the phenolate solution treatment by carbon dioxide. The absorption proceeds at higher pressure of 500 kPa and temperatures from 50 to 65 C, pure carbon dioxide is used and toluene is added. These conditions have the following favourable effects: (I) significant size reduction of the columns, (ii) it is possible to process more concentrated solutions without danger of silting the columns by crystallization of NaHCO{sub 3} on the packing. (iii) small amount of inert gas is released, (iv) lower alkalinity and better separability of the organic phase (phenols with toluene) from water phase (soda or bicarbonate solution) in separators.

  3. Preparation of acrylic acid-modified chitin improved by an experimental design and its application in absorbing toxic organic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Chao-Ming, E-mail: charming@mail.ksu.edu.tw [Department of Materials Engineering, Kun Shan University, Tainan, Taiwan (China); Chen, Lung-Chuan, E-mail: lcchen@mail.ksu.edu.tw [Department of Materials Engineering, Kun Shan University, Tainan, Taiwan (China); Yang, Hui-Chia, E-mail: yang.junkdna@gmail.com [Department of Environmental Engineering, Kun Shan University, Tainan, Taiwan (China); Li, Min-Hsing, E-mail: a1487561a@yahoo.com.tw [Department of Environmental Engineering, Kun Shan University, Tainan, Taiwan (China); Pan, Ting-Chung, E-mail: tcpan@mail.ksu.edu.tw [Department of Environmental Engineering, Kun Shan University, Tainan, Taiwan (China)

    2012-11-30

    Highlights: Black-Right-Pointing-Pointer Acrylic acid-modified chitin. Black-Right-Pointing-Pointer Experimental design. Black-Right-Pointing-Pointer Graft copolymerization. Black-Right-Pointing-Pointer Adsorption of toxic organic compounds. Black-Right-Pointing-Pointer Very high adsorption capacity. - Abstract: Chitin grafted poly (acrylic acid) (chi-g-PAA) is synthesized and characterized as an adsorbent of toxic organic compounds. Chi-g-PAA copolymers are prepared using of ammonium cerium (IV) nitrate (Ce{sup 4+}) as the initiator. The highest grafting percentage of AA in chitin obtained using the traditional technique is 163.1%. A maximum grafting percentage of 230.6% is obtained using central composite design (CCD). Experimental results are consistent with theoretical calculations. The grafted copolymer is characterized by Fourier transform Infrared spectroscopy and solid state {sup 13}C NMR. A representative chi-g-AA copolymer is hydrolyzed to a type of sodium salt (chi-g-PANa) and used in the adsorption of malachite green (MG), methyl violet (MV), and paraquat (PQ) in aqueous. The monolayer adsorption capacities of these substances are 285.7, 357.1, and 322.6 mg/g-adsorbent, respectively. Thermodynamic calculations show that the adsorption of MG, MV, and PQ are more favored at diluted solutions. The high adsorption capacity of chi-g-PANa for toxic matter indicates its potential in the treatment of wastewater and emergency treatment of PQ-poisoned patients.

  4. Mechanism Analysis of Absorbing Electromagnetic Wave in design of Microwave Anechoic Chamber%微波暗室设计中的吸波材料吸波机理分析

    Institute of Scientific and Technical Information of China (English)

    易鸣镝; 王冰; 王迪

    2016-01-01

    文章首先简述电磁波吸波材料的发展史,然后重点讨论广泛应用于微波暗室建设中的尖劈形吸波材料的几何吸波原理,并进行了数学推导,从理论上说明了电磁波在尖劈形吸波材料中能够形成多次反射,并给出了反射强度公式。籍此为暗室的设计及其测量误差的排查提供理论依据和理论分析方法。%This paper firstly gives a brief introduction to electromagnetic wave absorber wave material development history, and then introduce the ceiling materials in electromagnetic wave absorbing physical process, combined with the necessary experi-mental data on darkroom absorbing wave material selection is briefly discussed, finally focuses on discussion is widely used in the microwave anechoic chamber design in wedge-shaped absorber geometric wave absorbing mechanism, and the mathematic formulas are deduced. In theory illustrates the electromagnetic wave in the wedge-shaped absorber can form multiple reflection is presented, and the reflection intensity formula. Take this as the darkroom design and measurement error of the investigation provides a theoretical basis and theoretical analysis method.

  5. Multi-channel coherent perfect absorbers

    KAUST Repository

    Bai, Ping

    2016-05-18

    The absorption efficiency of a coherent perfect absorber usually depends on the phase coherence of the incident waves on the surfaces. Here, we present a scheme to create a multi-channel coherent perfect absorber in which the constraint of phase coherence is loosened. The scheme has a multi-layer structure such that incident waves in different channels with different angular momenta can be simultaneously and perfectly absorbed. This absorber is robust in achieving high absorption efficiency even if the incident waves become "incoherent" and possess "random" wave fronts. Our work demonstrates a unique approach to designing highly efficient metamaterial absorbers. © CopyrightEPLA, 2016.

  6. Optimal design and loss mechanism analysis of microwave absorbing unidirectional SiC fiber composites with broad absorption band and good polarization stability

    Science.gov (United States)

    Wan, Guangchao; Jiang, Jianjun; He, Yun; Bie, Shaowei

    2016-04-01

    A microwave-absorbing unidirectional SiC fiber composite with wide absorption and good polarization stability was designed by genetic algorithm. The anisotropic nature of unidirectional fiber composites was considered in the design by characterizing tensor permittivity. This special composite is composed of two kinds of SiC fibers that separately exhibit relatively high conductivity and low conductivity. The electromagnetic loss mechanism of this composite was examined for polarizations that differ in the electric field of the incident wave, applied either in the direction of the fiber or in the transverse direction, perpendicular to the fibers. For both polarizations, the absorption band of our composite can reach 6 GHz and the lowest microwave reflectivity was about -20 dB over a range of 8-18 GHz. When the electric field is polarized parallel to fibers, strong coupling among the high-conductivity fibers can induce a strong current and thus efficiently dissipate the electromagnetic energy. When the electric field is polarized perpendicular to fibers, the electromagnetic loss mechanism in the composite resembles the electric energy loss in capacitors and currents in the transverse direction are obstructed by the fibers resulting in attenuation of the electromagnetic energy in the matrix.

  7. Design and Experimental Research of Solar Blackbody Cavity Absorber%太阳能黑腔集热器的设计及实验研究

    Institute of Scientific and Technical Information of China (English)

    张晓晖; 姜伟娜; 徐鉴鉴

    2014-01-01

    在黑体概念的基础上,设计了1种新型太阳能腔体集热器,并进行了实验。新型太阳能腔体集热器利用黑腔的高吸收率、泡沫板的良好隔热性以及玻璃板营造的温室效应,使得集热器的整体热损失明显下降,从而提高了集热效率。测试结果表明:集热器内介质为水时,平均温升为15.1℃,最大温升为21℃,热效率最低为53%。各项热损失计算结果表明:黑腔辐射造成的热损失最大,反射热损失和对流热损失很小。新型太阳能腔体集热器结构紧凑,单位体积的有效吸热面积较平板太阳能集热器和真空管太阳能集热器大。%On the basis of traditional cavity absorber,a kind of new solar cavity-heat receiver is designed.With advantage of high absorptivity and good thermal insulation,the whole heat loss gets smaller and can obtain high thermal efficiency.The result of the experiment shows that the mean temperature rise is 15.1℃ and the highest temperature rise is 21℃ when water is filled,and the thermal efficiency is 53% under present situa-tion.The result of the thermal loss calculation indicates that radiation heat loss accounts for the most,while reflection heat loss and convection heat loss is small.The compact design has bigger effective heat absorbing area per volume than flat plate solar collector and evacuated tubular collector.

  8. Composite absorbing potentials

    CERN Document Server

    Palao, J P; Sala, P R

    1998-01-01

    The multiple scattering interferences due to the addition of several contiguous potential units are used to construct composite absorbing potentials that absorb at an arbitrary set of incident momenta or for a broad momentum interval.

  9. Carbon Absorber Retrofit Equipment (CARE)

    Energy Technology Data Exchange (ETDEWEB)

    Klein, Eric [Neumann Systems Group, Incorporated, Colorado Springs, CO (United States)

    2015-12-23

    During Project DE-FE0007528, CARE (Carbon Absorber Retrofit Equipment), Neumann Systems Group (NSG) designed, installed and tested a 0.5MW NeuStream® carbon dioxide (CO2) capture system using the patented NeuStream® absorber equipment and concentrated (6 molal) piperazine (PZ) as the solvent at Colorado Springs Utilities’ (CSU’s) Martin Drake pulverized coal (PC) power plant. The 36 month project included design, build and test phases. The 0.5MW NeuStream® CO2 capture system was successfully tested on flue gas from both coal and natural gas combustion sources and was shown to meet project objectives. Ninety percent CO2 removal was achieved with greater than 95% CO2product purity. The absorbers tested support a 90% reduction in absorber volume compared to packed towers and with an absorber parasitic power of less than 1% when configured for operation with a 550MW coal plant. The preliminary techno-economic analysis (TEA) performed by the Energy and Environmental Research Center (EERC) predicted an over-the-fence cost of $25.73/tonne of CO2 captured from a sub-critical PC plant.

  10. The ALICE absorbers

    CERN Multimedia

    Maximilien Brice

    2006-01-01

    Weighing more than 400 tonnes, the ALICE absorbers and the surrounding support structures have been installed and aligned with a precision of 1-2 mm, hardly an easy task but a very important one. The ALICE absorbers are made of three parts: the front absorber, a 35-tonne cone-shaped structure, and two small-angle absorbers, long straight cylinder sections weighing 18 and 40 tonnes. The three pieces lined up have a total length of about 17 m.

  11. 基于Smith圆图的吸波材料阻抗匹配设计%Impedance matching design of radar absorbing material based on Smith circle diagram

    Institute of Scientific and Technical Information of China (English)

    陈鑫; 刘祥萱

    2013-01-01

    采用Smith圆图对尖晶石镍铁氧体的输入阻抗进行表征,并根据传输线理论计算不同涂层厚度下尖晶石镍铁氧体的反射率。结果表明,Smith圆图中输入阻抗越接近点(α=1,β=0),阻抗匹配性越好,反射率也越小。这为基于Smith圆图的吸波材料阻抗匹配设计应用奠定了基础。%The input impedance of spinel nickel ferrite was characterized by Smith circle diagram,and the reflectivity of spinel nickel ferrite with different coating thicknesses was calculated by transmission line theory. The results show that the closer the input impedance in the Smith circle diagram is to the point(α=1,β=0),the better the impedance matching is,and the smaller the reflectance is,which lays the foundation for application of Smith circle diagram in impedance matching design of absorbing materials.

  12. Optimum design of composite panel with photovoltaic-thermo module. Absorbing effect of cooling panel; Hikari netsu fukugo panel no saiteki sekkei. Reikyaku panel no kyunetsu koka

    Energy Technology Data Exchange (ETDEWEB)

    Sato, M.; Kikuchi, S.; Tani, T. [Science University of Tokyo, Tokyo (Japan); Kadotani, K.; Imaizumi, H. [Komatsu Ltd., Tokyo (Japan)

    1996-10-27

    The composite panel with photovoltaic-thermo module becomes higher in energy-saving than the conventional air-conditioning system by the independent radiational heating and cooling effect obtained when the generating panel using a solar cell module is combined with the heating and cooling panel using a thermo-element module. The output of a solar cell module can be directly used because the solar cell module operates in AC. This paper reports the relation between the absorbed value and power consumption of the cooling panel, while paying attention to the cooling panel. The performance coefficient of the maximum absorbed value from an non-absorbing substance to a cooling panel is 2 to 3. Assume that the cooling panel during non-adiabatic operation is operated using a solar cell module of 800 W/m{sup 2} in solar intensity and 15% in conversion efficiency. The cooling-surface temperature difference is 12.12 K, and the maximum absorbed value of a non-absorbing substance to a cooling panel is 39.12 W/m{sup 2}. The absorbed value of the outer temperature to the cooling panel is 74.4 W/m{sup 2}, and each performance coefficient is 3.26 and 0.62. The absorbed value must be calculated for evaluation from the cooling-surface temperature difference measured directly from the cooling panel. 4 refs., 8 figs., 1 tab.

  13. Multiband Negative Permittivity Metamaterials and Absorbers

    Directory of Open Access Journals (Sweden)

    Yiran Tian

    2013-01-01

    Full Text Available Design and characteristics of multiband negative permittivity metamaterial and its absorber configuration are presented in this paper. The proposed multiband metamaterial is composed of a novel multibranch resonator which can possess four electric resonance frequencies. It is shown that, by controlling the length of the main branches of such resonator, the resonant frequencies and corresponding absorbing bands of metamaterial absorber can be shifted in a large frequency band.

  14. 吸振夹层壁板颤振抑制的吸振器频率设计%Frequency design of dynamic vibration absorbers for flutter suppression of a sandwich panel

    Institute of Scientific and Technical Information of China (English)

    杨飞; 杨智春; 王巍

    2009-01-01

    为了完善在夹层壁板的芯层安装微型动力吸振器来抑制壁板颤振这一新方案,研究了吸振夹层壁板中悬臂梁式动力吸振器的频率设计方法.基于壁板颤振的模态耦合机理,分别以单频率设计和双频率设计原则来确定吸振夹层壁板的吸振器频率.结果表明,所有微型吸振器按单频率设计时,存在一个不等于原夹层壁板颤振耦合模态频率和颤振频率的吸振器最佳设计频率,使得吸振夹层壁板的颤振速度最大;微型吸振器按双频率设计时,吸振夹层壁板的最大颤振速度远大于按单频率设计的最大颤振速度.%A novel scheme for panel flutter suppression was proposed here. In this scheme the panel was designed as a sandwich panel incorporated with distributed micro beam-type dynamic absorbers acting as its core layer. To improve this scheme, the frequency design method for a dynamic absorber was investigated in the present study. Based on the mode-coupling mechanism of panel flutter, the frequency design of dynamic absorber was performed according to a single- frequency design scheme and a double-frequency design scheme, respectively. Numerical simulation results showed that when all the micro dynamic absorbers were designed with the single-frequency design scheme, a maximum flutter speed for the sandwich panel could be achieved at the optimal absorber frequency, which was different from the flutter frequency or the natural modal frequencies of the original sandwich panel; and when the micro dynamic absorbers were designed with the double-frequency design scheme, a maximum flutter speed of the sandwich panel was much bigger than that obtained using the single-frequency design scheme.

  15. Mushroom plasmonic metamaterial infrared absorbers

    Science.gov (United States)

    Ogawa, Shinpei; Fujisawa, Daisuke; Hata, Hisatoshi; Uetsuki, Mitsuharu; Misaki, Koji; Kimata, Masafumi

    2015-01-01

    There has been a considerable amount of interest in the development of various types of electromagnetic wave absorbers for use in different wavelength ranges. In particular, infrared (IR) absorbers with wavelength selectivity can be applied to advanced uncooled IR sensors, which would be capable of identifying objects through their radiation spectrum. In the present study, mushroom plasmonic metamaterial absorbers (MPMAs) for the IR wavelength region were designed and fabricated. The MPMAs consist of a periodic array of thin metal micropatches connected to a thin metal plate with narrow silicon (Si) posts. A Si post height of 200 nm was achieved by isotropic XeF2 etching of a thin Si layer sandwiched between metal plates. This fabrication procedure is relatively simple and is consistent with complementary metal oxide semiconductor technology. The absorption spectra of the fabricated MPMAs were experimentally measured. In addition, theoretical calculations of their absorption properties were conducted using rigorous coupled wave analysis. Both the calculated and measured absorbance results demonstrated that these MPMAs can realize strong selective absorption at wavelengths beyond the period of the array by varying the micropatch width. Absorbance values greater than 90% were achieved. Dual- or single-mode absorption can also be selected by varying the width of the Si posts. Pixel structures using such MPMAs could be used as high responsivity, high resolution and fast uncooled IR sensors.

  16. Mushroom plasmonic metamaterial infrared absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Shinpei, E-mail: Ogawa.Shimpei@eb.MitsubishiElectric.co.jp; Fujisawa, Daisuke; Hata, Hisatoshi; Uetsuki, Mitsuharu; Misaki, Koji [Advanced Technology R and D Center, Mitsubishi Electric Corporation, 8-1-1 Tsukaguchi-Honmachi, Amagasaki, Hyogo 661-8661 (Japan); Kimata, Masafumi [College of Science and Engineering, Ritsumeikan University, 1-1-1 Noji-higashi, Kusatsu, Shiga 525-8577 (Japan)

    2015-01-26

    There has been a considerable amount of interest in the development of various types of electromagnetic wave absorbers for use in different wavelength ranges. In particular, infrared (IR) absorbers with wavelength selectivity can be applied to advanced uncooled IR sensors, which would be capable of identifying objects through their radiation spectrum. In the present study, mushroom plasmonic metamaterial absorbers (MPMAs) for the IR wavelength region were designed and fabricated. The MPMAs consist of a periodic array of thin metal micropatches connected to a thin metal plate with narrow silicon (Si) posts. A Si post height of 200 nm was achieved by isotropic XeF{sub 2} etching of a thin Si layer sandwiched between metal plates. This fabrication procedure is relatively simple and is consistent with complementary metal oxide semiconductor technology. The absorption spectra of the fabricated MPMAs were experimentally measured. In addition, theoretical calculations of their absorption properties were conducted using rigorous coupled wave analysis. Both the calculated and measured absorbance results demonstrated that these MPMAs can realize strong selective absorption at wavelengths beyond the period of the array by varying the micropatch width. Absorbance values greater than 90% were achieved. Dual- or single-mode absorption can also be selected by varying the width of the Si posts. Pixel structures using such MPMAs could be used as high responsivity, high resolution and fast uncooled IR sensors.

  17. Design of a new type of adjustable shock absorber for electric-controlled air suspension%电控空气悬架中的新型可调阻尼减振器设计

    Institute of Scientific and Technical Information of China (English)

    江浩斌; 孙鹏; 汪若尘; 熊新汉

    2011-01-01

    为满足某客车电控空气悬架的阻尼控制要求,以该车原被动式液压减振器为基础,研制了一种新型可调阻尼减振器,确定了减振器在"软"、"硬"阻尼状态下的阻尼力设计目标.该减振器的阻尼调节装置可实现2种阻尼状态的切换.介绍了该减振器的结构组成、工作原理及驱动机构的特点,应用流体力学理论建立了减振器的阻尼特性数学模型,通过仿真分析确定了减振器的主要结构参数.研制了减振器样件并进行了台架性能试验.试验结果与仿真结果基本吻合,验证了减振器设计方案和数学模型的有效性.试验过程中,减振器的2种阻尼状态的切换控制准确、稳定,为电控半主动空气悬架设计提供了技术支持.%To meet the damping control demand of an electric-controlled air suspension in bus the structure of an adjustable shock absorber with two-levels damp is designed based on the passive hydraulic shock absorber of a bus. The design goal of shock absorber's damping force under ‘hard' and ‘soft' damping situation is decided. The damping adjusting device makes the shifting of two damping situations possible through solenoid controlling swing cylinder. The structure and working principle of the adjustable shock absorber are introduced. The mathematical model of adjustable shock absorber's damping characteristics is established by fluid mechanic theory. Structural parameters of shock absorber are decided by simulation. Adjustable shock absorber specimen is developed, and its damping performance is tested. It shows that test data agree well with the simulation results, the validities of structure design and simulation model of adjustable shock absorber are verified. The shifting control of two damping situations is accurate and stable in the process of bench test. Thus it provides new technology for development of electric-controlled semi-active air suspension.

  18. A Six-Fold Symmetric Metamaterial Absorber

    Directory of Open Access Journals (Sweden)

    Humberto Fernández Álvarez

    2015-04-01

    Full Text Available A novel microwave metamaterial absorber design is introduced along with its manufacturing and characterization. Significant results considering both bandwidth and angular stability are achieved. Parametric analysis and simplified equivalent circuit are provided to give an insight on the key elements influencing the absorber performance. In addition, the constitutive parameters of the effective medium model are obtained and related to the absorber resonant behavior. Moreover, a new thinner and more flexible absorber version, preserving broad bandwidth and angular insensitive performance, is simulated, and an 8 × 8 unit-cells prototype is manufactured and measured for a limited angular margin in an anechoic chamber.

  19. Tuned mass absorber on a flexible structure

    DEFF Research Database (Denmark)

    Krenk, Steen; Høgsberg, Jan Becker

    2014-01-01

    The classic design of a tuned mass absorber is based on a simple two-mass analogy in which the tuned mass is connected to the structural mass with a spring and a viscous damper. In a flexible multi-degree-of-freedom structure the tuned mass absorber is typically introduced to provide damping...... of a specific mode. The motion of the point of attachment of the tuned mass absorber to the structure has not only a contribution from the targeted mode, but also a background contribution from other non-resonant modes. Similarly, the force provided by the tuned mass absorber is distributed between the targeted...

  20. Metamaterial absorber with random dendritic cells

    Science.gov (United States)

    Zhu, Weiren; Zhao, Xiaopeng

    2010-05-01

    The metamaterial absorber composed of random dendritic cells has been investigated at microwave frequencies. It is found that the absorptivities come to be weaker and the resonant frequency get red shift as the disordered states increasing, however, the random metamaterial absorber still presents high absorptivity more than 95%. The disordered structures can help understanding of the metamaterial absorber and may be employed for practical design of infrared metamaterial absorber, which may play important roles in collection of radiative heat energy and directional transfer enhancement.

  1. An ultrathin dual-band metamaterial absorber

    Science.gov (United States)

    Zhang, Yong; Duan, Junping; Zhang, Wendong; Wang, Wanjun; Zhang, Binzhen

    2016-10-01

    The design and preparation of an ultrathin dual-band metamaterial absorber whose resonant frequency located at radar wave (20 GHz-60 GHz) is presented in this paper. The absorber is composed of a 2-D periodic sandwich featured with two concentric annuluses. The influence on the absorber's performance produced by resonant cell's structure size and material parameters was numerically simulated and analyzed based on the standard full wave finite integration technology in CST. Laser ablation process was adopted to prepare the designed absorber on epoxy resin board coated with on double plane of copper with a thickness that is 1/30 and 1/50 of the resonant wavelength at a resonant frequency of 30.51 GHz and 48.15 GHz. The full width at half maximum (FWHM) reached 2.2 GHz and 2.35 GHz and the peak of the absorptance reached 99.977%. The ultrathin absorber is nearly omnidirectional for all polarizations. The test results of prepared sample testify the designed absorber's excellent absorbing performance forcefully. The absorber expands inspirations of radar stealth in military domain due to its flexible design, cost-effective and other outstanding properties.

  2. Registro Absorb Italiano (BVS-RAI): an investigators-owned and -directed, open, prospective registry of consecutive patients treated with the Absorb™ BVS: study design

    Energy Technology Data Exchange (ETDEWEB)

    Cortese, Bernardo, E-mail: bcortese@gmail.com [Azienda Ospedaliera Fatebenefratelli e Oftalmico, Milano (Italy); Ielasi, Alfonso [Azienda Ospedaliera Bolognini, Seriate (Italy); Varricchio, Attilio [Ospedale Monaldi, Napoli (Italy); Tarantini, Giuseppe [Azienda Ospedaliera Universitaria, Padova (Italy); LaVecchia, Luigi [Azienda Ospedaliera San Bortolo, Vicenza (Italy); Pisano, Francesco [Ospedale Regionale, Aosta (Italy); Facchin, Michela [Ospedale di Este (Italy); Gistri, Roberto [Ospedale S. Andrea, La Spezia (Italy); D’Urbano, Maurizio [Ospedale di Magenta (Italy); Lucci, Valerio [Ospedale di Avezzano (Italy); Loi, Bruno [Azienda Ospedaliera Brotzu, Cagliari (Italy); Tumminello, Gabriele [Ospedale Cardinal Massaia, Asti (Italy); Colombo, Alessandro [Ospedale Sacco, Milano (Italy); Limbruno, Ugo [Ospedale della Misericordia, Grosseto (Italy); Nicolino, Annamaria [Ospedale Santa Corona, Pietra Ligure (Italy); Calzolari, Diego [Azienda Ospedaliera Ca Foncello, Treviso (Italy); Tognoni, Gianni [Centro di Ricerche Farmacologiche e Biomediche ' Mario Negri' , Milano (Italy); Defilippi, Gianfranco [Ospedale Cardinal Massaia, Asti (Italy); Buccheri, Dario [Azienda Ospedaliera Fatebenefratelli e Oftalmico, Milano (Italy); Tespili, Maurizio [Azienda Ospedaliera Bolognini, Seriate (Italy); and others

    2015-09-15

    Background: The Absorb™ BVS is a bioresorbable, everolimus-eluting scaffold approved and marketed for coronary use. Published data on long-term results after treatment are limited to a small number of patients, most of them with elective PCI of simple lesions. The importance of scaffold resorption is variably appreciated among cardiologists, and indications for use from health technology assessment bodies or guidelines are missing. Instruments are needed to collect, share and assess the experience being accumulated with this new device in several centres. Methods/Design: The BVS-RAI Registry is a spontaneous initiative of a group of Italian interventional cardiologists in cooperation with Centro di Ricerche Farmacologiche e Biomediche 'Mario Negri' Institute, and is not recipient of funding or benefits originating from the BVS manufacturer. It is a prospective registry with 5-year follow-up of all consecutive patients who have undergone successful implantation of 1 or more coronary BVS following the indications, techniques and protocols used in each of the participating institutions. Outcome measures are BVS target lesion failure within one year and device-oriented major adverse cardiac events within 5 years. The registry started in October 2012 and will extend enrolment throughout 2015, with the aim to include about 1000 patients. ClinicalTrials.gov identifier is CT02298413. Conclusions: The BVS-RAI Registry will contribute observational knowledge on the long-term safety and efficacy of the Absorb™ BVS as used in a number of Italian interventional centres in a broad spectrum of settings. Unrewarded and undirected consecutive patient enrolments are key-features of this observation, which is therefore likely to reflect common clinical practice in those centres. - Highlights: • prospective data collection of successful Absorb implantation; • expert Italian centers; • no restrictions for enrollment/no exclusion criteria; • clinical follow up;

  3. Design of microwave absorbing asphalt mixture pavement material%吸波沥青混合料路面材料设计

    Institute of Scientific and Technical Information of China (English)

    袁斌; 刘銮成; 李敬才

    2012-01-01

    Directing against low microwave absorbing property of limestone aggregate asphalt mixture,asphalt mixture absorbing microwave with 3∶ 7 and limestone aggregate was prepared.The mixture was heated with a microwave oven for 60 s and the surface temperature was measured.The results indicate that the asphalt mixture absorbing microwave had higher temperature enhancement efficiency.%针对普通石灰岩集料沥青混合料吸波效率低等问题,按照铁矿石集料与普通石灰岩集料体积比3∶7,配制吸波沥青混合料,利用微波炉并加热60 s后,测试混合料表面温度差别,结果表明,吸波沥青混合料具有明显的升温效率高的特点。

  4. Design and Research of Hydraulic Absorber for Building%房屋液压减震装置的设计与研究

    Institute of Scientific and Technical Information of China (English)

    高军霞; 杨国权; 郭子利

    2011-01-01

    介绍一种房屋液压减震器实验装置,建立其数学模型,通过MATLAB/Simulink对该装置的减震效果进行仿真分析。仿真和实物模型演示结果表明:在地震来临瞬间,应用该装置的建筑物减震效果显著。%A type of experimental device of hydraulic absorber for building was introduced. Its mathematical model was built. The hydraulic absorber for building was simulated by MATLAB/Simulink. The simulation and physical model experimental results show the hydraulic absorber for building has significant damping effect when earthquake comes.

  5. Advanced neutron absorber materials

    Science.gov (United States)

    Branagan, Daniel J.; Smolik, Galen R.

    2000-01-01

    A neutron absorbing material and method utilizing rare earth elements such as gadolinium, europium and samarium to form metallic glasses and/or noble base nano/microcrystalline materials, the neutron absorbing material having a combination of superior neutron capture cross sections coupled with enhanced resistance to corrosion, oxidation and leaching.

  6. Design of Sound Absorber of Urban Rail way Station and Its Performance Testing%适用于城市轨道交通车站的吸声体设计及其性能测试

    Institute of Scientific and Technical Information of China (English)

    徐文君; 李双

    2012-01-01

    根据城市轨道交通车站的结构特点和噪声特性,设计并制作有空腔的吸声体;将1/4波长声管设置于吸声体中,以提高其对中低频轮轨噪声的吸收能力.通过单传声器脉冲响应法测试吸声体样品的吸声性能,结果表明:加装空腔和布置声管后,吸声体的中低频吸声能力明显提高.最后应用ANSYS和SYSNOISE软件,分别计算出安装该吸声体前后的车站声场,结果显示:安装吸声体后,候车点的声压降低2~5dB.%Based on the structural and noise characteristics of urban railway stations, a sound absorber with wooden cavity structure was designed and 1/4 wavelength sound tube was installed in the absorber to increase its absorption capacity for the noises of middle and low frequencies. The Impulse Response Method (IRM) with single microphone was used to test the sound absorber' s absorption coefficient. The result shows that absorption capacity of the absorber for the noise of low and middle frequencies is greatly enhanced after the cavity and sound tube have been placed in. The sound fields of an urban rail transit station before and after sound absorber installation was calculated respectively by means of the software ANSYS and SYSNOISE. The results show that sound pressure of waiting point on the platform can be reduced by 2 -5 dB.

  7. Rational Molecular Design and Synthesis of Highly Thermo- and Photostable Near-Infrared-Absorbing Heptamethine Cyanine Dyes with the Use of Fluorine Atoms.

    Science.gov (United States)

    Funabiki, Kazumasa; Yagi, Kazutaka; Ueta, Masato; Nakajima, Mitsuru; Horiuchi, Masako; Kubota, Yasuhiro; Mastui, Masaki

    2016-08-22

    Highly thermo- and photostable, near-infrared-absorbing heptamethine cyanine dyes were achieved with the use of fluorine-containing components. In particular, one prepared heptamethine cyanine dye, bearing a tetrakis(pentafluorophenyl)borate as a counter anion and an N-ethyl-2,2,2-trifluoroacetamido group at the meso position, showed not only a high decomposition temperature (Tdt ), but also very high photostability toward white LED irradiation.

  8. Graphene metamaterials based tunable terahertz absorber: effective surface conductivity approach.

    Science.gov (United States)

    Andryieuski, Andrei; Lavrinenko, Andrei V

    2013-04-08

    In this paper we present the efficient design of functional thin-film metamaterial devices with the effective surface conductivity approach. As an example, we demonstrate a graphene based perfect absorber. After formulating the requirements to the perfect absorber in terms of surface conductivity we investigate the properties of graphene wire medium and graphene fishnet metamaterials and demonstrate both narrowband and broadband tunable absorbers.

  9. Graphene metamaterials based tunable terahertz absorber: effective surface conductivity approach

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Lavrinenko, Andrei

    2013-01-01

    In this paper we present the efficient design of functional thin-film metamaterial devices with the effective surface conductivity approach. As an example, we demonstrate a graphene based perfect absorber. After formulating the requirements to the perfect absorber in terms of surface conductivity...... we investigate the properties of graphene wire medium and graphene fishnet metamaterials and demonstrate both narrowband and broadband tunable absorbers....

  10. TOMS Absorbing Aerosol Index

    Data.gov (United States)

    Washington University St Louis — TOMS_AI_G is an aerosol related dataset derived from the Total Ozone Monitoring Satellite (TOMS) Sensor. The TOMS aerosol index arises from absorbing aerosols such...

  11. Electrodynamic absorber theory

    OpenAIRE

    Deckert, Dirk-André

    2010-01-01

    This work deals with questions that arise in classical and quantum electrodynamics when describing the phenomena of radiation reaction and pair creation. The two guiding ideas are the absorber idea of Wheeler and Feynman (i.e. all emitted radiation will be again be absorbed by matter) and the electron sea idea of Dirac. In the first part classical dynamics are studied which allow for a description of radiation reaction without the need of renormalization. The starting point are the couple...

  12. The optimum design with multiple target of the inspection device with rebber shock-absorbing cushion%橡胶减振垫送检装置的多目标规划优化设计研究

    Institute of Scientific and Technical Information of China (English)

    石怀荣; 芮延年; 张辉

    2011-01-01

    基于机构工作目标和机构运动学特性,采用多目标规划优化设计的方法,研制满足检测减振垫性能的送检机械装置.以满足机构工作特性及机构性能指标为设计优化基础,建立送检机构运动特性、结构参数以及机构工作性能的多目标优化计算模型.研究分析各目标函数间的相互关联性,建立减振垫送检装置的多目标规划优化设计模型,确定机构优化设计目标函数,以便为自主研发新型、高效减振垫性能检测机械装置提供支持.%According as the optimum design with multiple target and the organizational working goal and characteristic of organizational movement, so that develop the inspection decive to check functions of rebber shock-absorbing cushion. The optimum design based on satisfied the working characteristic and performance of machine, then made the computational model by the optimum design with multiple with motion characteristic ,configuration parameter and working function of the inspection. The model of the optimum design with multiple target of the inspection device with rebber shock-absorbing cushion which set up by the relevance research of each object function,finally establish the optimum design with target. Thus the theoretical principle was been set up to self-developed the inspection device with rebber shock-absorbing cushion by functional, effectively and continuable.

  13. Effect of inclusions' distribution on microwave absorbing properties of composites

    Science.gov (United States)

    Qin, Siliang; Wang, Qingguo; Qu, Zhaoming

    2013-03-01

    Effect of inclusions' spatial distributions on the permeability and permittivity of composites is studied using the generalized Maxwell-Garnett equations. The result indicates that inclusions' orientation distribution can increase the longitudinal electromagnetic parameters. For inclusions' random and orientation distribution, single and three-layer absorbers are designed and optimized using genetic algorithm. The result shows that under a given absorbing requirement, absorber with inclusions' orientation distribution is lighter and thinner than absorber with inclusions' random distribution.

  14. 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......Minorsky's well-known empirical formula, which relates the absorbed energy to the destroyed material volume, has been widely used in analyses of high energy collision and grounding accidents for nearly 40 years. The advantage of the method is its apparent simplcity. Obviously, its drawback...

  15. 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....

  16. Reactivity Flattening for a Soluble Boron-Free Small Modular Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Park, JinHa; Kang, JungKil; Hah, ChangJoo [KINGS, Ulsan (Korea, Republic of)

    2015-10-15

    In this study, it is found that double-layered BP rod with same absorber material, B{sub 4}C/B{sub 4}C, is the most efficient candidate of BP for a SBF reactor. This burnable absorber is flexible to cope with various reactivity shapes by adjusting the thickness of absorber material, weight ratio of Al{sub 2}O{sub 3} and B{sub 4}C, and it can be used like a single-layered burnable absorber by replacing outer layer with air. The results of depletion calculation verify that core excess reactivity can be well controlled, and show that core radial power distributions are also well flattened over the entire core burnup. Removing soluble boron from the primary coolant system brings many benefits of simplifying the reactor operation and maintenance. Although a Soluble Boron-Free (SBF) operation has a lot of advantages, there are several barriers to overcome such as heavily bottom skewed axial power distribution due to the strong negative MTC, control rod design to secure the reactivity shutdown margin, and excess reactivity holddown by using burnable absorbers and control rods, etc. For these reasons, there is no practical boron-free power operation in the world in spite of many studies on the SBF reactor. Burnable absorbers and control rods are the only available means, so far, to compensate excess reactivity for a SBF reactor. Frequent use of the control rods, however, can give a big burden to operators, and deep insertion of the control rods can cause fuel damage when Reactivity Initiated Accident (RIA) occurs like CEA ejection and bank withdrawal. The purpose of this study is to design a new conceptual burnable absorber to achieve flat reactivity from Beginning Of Cycle (BOC) to End Of Cycle (EOC). For these reasons, firstly, we carry out the investigation of the nuclear characteristics of the 17X17 WH (WestingHouse) type Fuel Assembly (FA) containing various burnable absorbers which have been widely used in PWR. Secondly, three kinds of new conceptual Burnable Poison

  17. Graphene and Graphene Metamaterials for Terahertz Absorbers

    OpenAIRE

    Andryieuski, Andrei; Pizzocchero, Filippo; Booth, Tim; Bøggild, Peter

    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...

  18. Perfect terahertz absorber using fishnet based metafilm

    Energy Technology Data Exchange (ETDEWEB)

    Azad, Abul Kalam [Los Alamos National Laboratory; Shchegolkov, Dmitry Yu [Los Alamos National Laboratory; Chen, Houtong [Los Alamos National Laboratory; Taylor, Antoinette [Los Alamos National Laboratory; Smirnova, E I [Los Alamos National Laboratory; O' Hara, John F [Los Alamos National Laboratory

    2009-01-01

    We present a perfect terahertz (THz) absorber working for a broad-angle of incidence. The two fold symmetry of rectangular fishnet structure allows either complete absorption or mirror like reflection depending on the polarization of incident the THz beam. Metamaterials enable the ability to control the electromagnetic wave in a unique fashion by designing the permittivity or permeability of composite materials with desired values. Although the initial idea of metamaterials was to obtain a negative index medium, however, the evolution of metamaterials (MMs) offers a variety of practically applicable devices for controlling electromagnetic wave such as tunable filters, modulators, phase shifters, compact antenna, absorbers, etc. Terahertz regime, a crucial domain of the electromagnetic wave, is suffering from the scarcity of the efficient devices and might take the advantage of metamaterials. Here, we demonstrate design, fabrication, and characterization of a terahertz absorber based on a simple fishnet metallic film separated from a ground mirror plane by a dielectric spacer. Such absorbers are in particular important for bolometric terahertz detectors, high sensitivity imaging, and terahertz anechoic chambers. Recently, split-ring-resonators (SRR) have been employed for metamaterial-based absorbers at microwave and THz frequencies. The experimental demonstration reveals that such absorbers have absorptivity close to unity at resonance frequencies. However, the downside of these designs is that they all employ resonators of rather complicated shape with many fine parts and so they are not easy to fabricate and are sensitive to distortions.

  19. Adaptive Piezoelectric Absorber for Active Vibration Control

    Directory of Open Access Journals (Sweden)

    Sven Herold

    2016-02-01

    Full Text Available Passive vibration control solutions are often limited to working reliably at one design point. Especially applied to lightweight structures, which tend to have unwanted vibration, active vibration control approaches can outperform passive solutions. To generate dynamic forces in a narrow frequency band, passive single-degree-of-freedom oscillators are frequently used as vibration absorbers and neutralizers. In order to respond to changes in system properties and/or the frequency of excitation forces, in this work, adaptive vibration compensation by a tunable piezoelectric vibration absorber is investigated. A special design containing piezoelectric stack actuators is used to cover a large tuning range for the natural frequency of the adaptive vibration absorber, while also the utilization as an active dynamic inertial mass actuator for active control concepts is possible, which can help to implement a broadband vibration control system. An analytical model is set up to derive general design rules for the system. An absorber prototype is set up and validated experimentally for both use cases of an adaptive vibration absorber and inertial mass actuator. Finally, the adaptive vibration control system is installed and tested with a basic truss structure in the laboratory, using both the possibility to adjust the properties of the absorber and active control.

  20. Neutron absorbing alloy

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Masayuki

    1998-12-04

    The neutron absorbing alloy of the present invention comprises Ti or an alloy thereof as a mother material, to which from 2 to 40% by weight of Hf and Gd within a range of from 4 to 50% by weight in total are added respectively. Ti is excellent in specific strength, corrosion resistance and workability, and produces no noxious intermetallic compound with Hf and Gd. In addition, since the alloy can incorporate a great quantity of Hf and Gd, a neutron absorbing material having excellent neutron absorbing performance than usual and excellent in specific strength, corrosion resistance and workability can be manufactured conveniently and economically not by a special manufacturing method. (T.M.)

  1. Nuclear design report for system-integrated modular advanced reactor

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sang Yoon; Lee, Chung Chan; Zee, Sung Quun; Chang, Moon Hee [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2002-02-01

    This report presents nuclear characteristics analysis results for SMART. Information is given on fuel loading, power density distributions, reactivity coefficients and control rod worths. The core consists of 57 modified Korean Standard Fuel Assemblies (m-KOFAs). and all fuel assemblies contain burnable absorbers to control the power distribution and the excess reactivity that is required for soluble boron-free and ultra longer cycle operation. The cycle length of SMART amounts to 990 EFPD corresponding to a cycle burnup of 26,160 MWD/MTU. 4 refs., 92 figs., 5 tabs. (Author)

  2. Solar concentrator/absorber

    Science.gov (United States)

    Von Tiesenhausen, G. F.

    1976-01-01

    Collector/energy converter, consisting of dual-slope optical concentrator and counterflow thermal energy absorber, is attached to multiaxis support structure. Efficient over wide range of illumination levels, device may be used to generate high temperature steam, serve as solar powered dryer, or power absorption cycle cooler.

  3. An ultra-broadband multilayered graphene absorber

    KAUST Repository

    Amin, Muhammad

    2013-01-01

    An ultra-broadband multilayered graphene absorber operating at terahertz (THz) frequencies is proposed. The absorber design makes use of three mechanisms: (i) The graphene layers are asymmetrically patterned to support higher order surface plasmon modes that destructively interfere with the dipolar mode and generate electromagnetically induced absorption. (ii) The patterned graphene layers biased at different gate voltages backedup with dielectric substrates are stacked on top of each other. The resulting absorber is polarization dependent but has an ultra-broadband of operation. (iii) Graphene\\'s damping factor is increased by lowering its electron mobility to 1000cm 2=Vs. Indeed, numerical experiments demonstrate that with only three layers, bandwidth of 90% absorption can be extended upto 7THz, which is drastically larger than only few THz of bandwidth that can be achieved with existing metallic/graphene absorbers. © 2013 Optical Society of America.

  4. THE INFLUENCE OF CaO AND P2O5 OF BONE ASH UPON THE REACTIVITY AND THE BURNABILITY OF CEMENT RAW MIXTURES

    Directory of Open Access Journals (Sweden)

    TOMÁŠ IFKA

    2012-03-01

    Full Text Available The influence of CaO and P2O5 upon the reactivity of cement raw meal was investigated in this paper. Ash of bone meal containing Ca3(PO42 - 3CaO·P2O5 was used as the source of P2O5. Two series of samples with different content of the ash of bone meal were prepared. In the first series, the ash of bone was added into cement raw meal. The second series of samples were prepared by considering ash as one of CaO sources. Therefore, the total content of CaO in cement raw meal was kept constant, while the amount of P2O5 increased. These different series of samples were investigated by analyzing free lime content in the clinkers. The XRD analysis and Electron Micro Probe Analyzer analysis of the clinkers were also carried out. Two parameters were used to characterize the reactivity of cement raw meal: content of free lime and Burnability Index (BI calculated from free lime content in both series of samples burnt at 1350 ºC, 1400 ºC, 1450 ºC and 1500 ºC. According to the first parameter, P2O5 content that drastically makes worse the reactivity of cement raw meal was found at 1.11 wt.% in the first series, while this limit has reached 1.52 wt.% in the second one. According to the BI, the limit of P2O5 was found at 1.42 wt. % in the first series and 1, 61 wt.% in the second one. Furthermore, EPMA has demonstrated the presence of P2O5 in both calcium silicate phases forming thus solid solutions.

  5. Galaxy Clusters in the Line of Sight to Background Quasars: I. Survey Design and Incidence of MgII Absorbers at Cluster Redshifts

    CERN Document Server

    López, S; Lira, P; Padilla, N; Gilbank, D G; Gladders, M D; Maza, J; Tejos, N; Vidal, M; Yee, H K C

    2008-01-01

    We describe the first optical survey of absorption systems associated with galaxy clusters at z= 0.3-0.9. We have cross-correlated SDSS DR3 quasars with high-redshift cluster/group candidates from the Red-Sequence Cluster Survey. We have found 442 quasar-cluster pairs for which the MgII doublet might be detected at a transverse (physical) distance d2.0 Ang.) near cluster redshifts shows a significant (>3 sigma) overabundance (up to a factor of 15) when compared with the 'field' population; (2) the overabundance is more evident at smaller distances (d<1 Mpc) than larger distances (d<2 Mpc) from the cluster center; and, (3) the population of weak MgII systems (W_0<0.3 Ang.) near cluster redshifts conform to the field statistics. Unlike in the field, this dichotomy makes n(W) in clusters appear flat and well fitted by a power-law in the entire W-range. A sub-sample of the most massive clusters yields a stronger and still significant signal. Since either the absorber number density or filling-factor/cros...

  6. The Design Thinking of the Concentrated Absorb Refrigeration System%一种聚光吸附式制冷系统的设计思路

    Institute of Scientific and Technical Information of China (English)

    赵书东

    2016-01-01

    With the environmental pollution aggravation and fossil fuel depletion,harnessing the power of the sun directly or indirectly remains at the core of future energy scenarios,this article put forward a suspect to combine the technology of Concentrated Photo Voltaic and Adsorption Refrigeration creatively,and use the example of 30 degrees north latitude Chinese city,described the theoretical feasibility of the concentrated absorb refrigeration.%随着化石能源的消耗和环境污染的加剧,直接或间接利用太阳能成为了未来能源模式的核心内容之一,本文创新地提出了将聚光光伏技术和太阳能吸附式制冷技术相结合的思路,并以中国北纬30度的城市为例,阐述了聚光吸附式制冷的理论可行性。

  7. Absorbable and biodegradable polymers

    CERN Document Server

    Shalaby, Shalaby W

    2003-01-01

    INTRODUCTION NOTES: Absorbable/Biodegradable Polymers: Technology Evolution. DEVELOPMENT AND APPLICATIONOF NEW SYSTEMS: Segmented Copolyesters with Prolonged Strength Retention Profiles. Polyaxial Crystalline Fiber-Forming Copolyester. Polyethylene Glycol-Based Copolyesters. Cyanoacrylate-Based Systems as Tissue Adhesives. Chitosan-Based Systems. Hyaluronic Acid-Based Systems. DEVELOPMENTS IN PREPARATIVE, PROCESSING, AND EVALUATION METHODS: New Approaches to the Synthesis of Crystalline. Fiber-Forming Aliphatic Copolyesters. Advances in Morphological Development to Tailor the Performance of Me

  8. Clustering of Absorbers

    CERN Document Server

    Cristiani, S; D'Odorico, V; Fontana, A; Giallongo, E; Moscardini, L; Savaglio, S

    1997-01-01

    The observed clustering of Lyman-$\\alpha$ lines is reviewed and compared with the clustering of CIV systems. We argue that a continuity of properties exists between Lyman-$\\alpha$ and metal systems and show that the small-scale clustering of the absorbers is consistent with a scenario of gravitationally induced correlations. At large scales statistically significant over and under-densities (including voids) are found on scales of tens of Mpc.

  9. Ionized Absorbers in AGN

    Science.gov (United States)

    Mathur, S.

    1999-01-01

    As a part of this program, we observed three AGN:PKS2251 + 113, PG0043 = 039 and PLH909. Two objects show signatures of absorbtion in their UV spectra. Based on our earlier modeling of X-ray warm absorbents, we expected to observe X-ray observation in these objects. The third, PLH909, is known to have soft excess in EINSTEIN data. Attachment: "Exploratory ASCA observation of broad absorption line quasi-stellar objects".

  10. Theory of microslit absorbers

    Institute of Scientific and Technical Information of China (English)

    MAA Dah-You

    2001-01-01

    It is well known that narrow slit may be used as acoustical element. The exact formulae of the acoustical impedance of a narrow slit and its low-frequency approximation are available. The theory of slit is extended and a simple and practical formula is derived for the single slit. It is found that the resistance-to-reactance ratio of the slit increases to larger than one when the slit width is decreased to submillimeter range, and a panel with extremely narrow slits plus a back cavity will make an absorber with good absorption in a wide frequency range,without any porous or fibrous material. A complete theory of the microslit absorber (MSA) is, thus, presented and its absorption characteristics discussed. It is found that the MSA has essentially the same formulae as the microperforate absorber (MPA), except that the numerical coefficient of the resistance is smaller and the end correction for the mass reactance is larger for the MSA, resulting a performance inferior to that of MPA, ordinarily. Measures are proposed to compensate for these.

  11. Absorber for terahertz radiation management

    Science.gov (United States)

    Biallas, George Herman; Apeldoorn, Cornelis; Williams, Gwyn P.; Benson, Stephen V.; Shinn, Michelle D.; Heckman, John D.

    2015-12-08

    A method and apparatus for minimizing the degradation of power in a free electron laser (FEL) generating terahertz (THz) radiation. The method includes inserting an absorber ring in the FEL beam path for absorbing any irregular THz radiation and thus minimizes the degradation of downstream optics and the resulting degradation of the FEL output power. The absorber ring includes an upstream side, a downstream side, and a plurality of wedges spaced radially around the absorber ring. The wedges form a scallop-like feature on the innermost edges of the absorber ring that acts as an apodizer, stopping diffractive focusing of the THz radiation that is not intercepted by the absorber. Spacing between the scallop-like features and the shape of the features approximates the Bartlett apodization function. The absorber ring provides a smooth intensity distribution, rather than one that is peaked on-center, thereby eliminating minor distortion downstream of the absorber.

  12. Fractal Absorbing Body Design and Its Application in Microstrip Antenna%分形吸波体设计及其在微带天线中的应用

    Institute of Scientific and Technical Information of China (English)

    商楷; 曹祥玉; 高军; 杨欢欢; 郑秋容

    2013-01-01

    基于Hilbert分形结构,设计了一种小型化、超薄、高吸波率以及无表面损耗层的超材料吸波体,该吸波体单元尺寸仅为0.071λ,厚度约0.02λ,吸波率达99.3%.将该吸波体与普通微带天线共形设计,制备了一种新型超材料天线.与初始天线相比,新天线的单站和双站带内雷达散射截面都有明显减缩,最大减缩达到7.2 dB,且天线辐射性能保持不变,证实了该吸波体具有良好的吸波效果.仿真和实测结果吻合得很好,表明该吸波体可以应用于微带天线的带内隐身.%A metamaterial absorber based on hilbert fractal structure is designed with miniaturization,slim,high absorptivity and no surface ullage layer.Its unit size is only 0.071λ,the thickness is about 0.02λ and the absorber can exhibit absorption of 99.3 %.It is conformed on microstrip antenna to preparation of a novel metamaterial antenna.Compared with the conventional microstrip antenna,the proposed antenna has a obvious monstatic and bistatic radar cross section reduction at the working frequency band.the greatest decrement can amounted to 7.2 dB,while the radiation performance is kept,which proves that the absorber had an excellent absorptivity.The simulation and measured resultes are in good agreement,indicating that the absorbing body can be applied to microstrip antennas to achieve in-band stealth.

  13. 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.

  14. A sound absorbing metasurface with coupled resonators

    Science.gov (United States)

    Li, Junfei; Wang, Wenqi; Xie, Yangbo; Popa, Bogdan-Ioan; Cummer, Steven A.

    2016-08-01

    An impedance matched surface is able, in principle, to totally absorb the incident sound and yield no reflection, and this is desired in many acoustic applications. Here we demonstrate a design of impedance matched sound absorbing surface with a simple construction. By coupling different resonators and generating a hybrid resonance mode, we designed and fabricated a metasurface that is impedance-matched to airborne sound at tunable frequencies with subwavelength scale unit cells. With careful design of the coupled resonators, over 99% energy absorption at central frequency of 511 Hz with a 50% absorption bandwidth of 140 Hz is achieved experimentally. The proposed design can be easily fabricated, and is mechanically stable. The proposed metasurface can be used in many sound absorption applications such as loudspeaker design and architectural acoustics.

  15. A variable passive low-frequency absorber

    DEFF Research Database (Denmark)

    Larsen, Niels Werner; Thompson, Eric Robert; Gade, Anders

    2005-01-01

    typically been too expensive or requires too much space to be practical for multi-purpose halls. Measurements were made on a variable low-frequency absorber to develop a practical solution to the dilemma. The paper will present the results of the measurements as well as a possible design....

  16. Shock-Absorbent Ball-Screw Mechanism

    Science.gov (United States)

    Hirr, Otto A., Jr.; Meneely, R. W.

    1986-01-01

    Actuator containing two ball screws in series employs Belleville springs to reduce impact loads, thereby increasing life expectancy. New application of springs increases reliability of equipment in which ball screws commonly used. Set of three springs within lower screw of ball-screw mechanism absorbs impacts that result when parts reach their upper and lower limits of movement. Mechanism designed with Belleville springs as shock-absorbing elements because springs have good energy-to-volume ratio and easily stacked to attain any stiffness and travel.

  17. Optically Modulated Multiband Terahertz Perfect Absorber

    DEFF Research Database (Denmark)

    Seren, Huseyin R.; Keiser, George R.; Cao, Lingyue

    2014-01-01

    response of resonant metamaterials continues to be a challengingendeavor. Resonant perfect absorbers have flourished as one of the mostpromising metamaterial devices with applications ranging from power har-vesting to terahertz imaging. Here, an optically modulated resonant perfectabsorber is presented....... Utilizing photo-excited free carriers in silicon padsplaced in the capacitive gaps of split ring resonators, a dynamically modu-lated perfect absorber is designed and fabricated to operate in reflection.Large modulation depth (38% and 91%) in two absorption bands (with 97%and 92% peak absorption...

  18. Ferroelectrics based absorbing layers

    Science.gov (United States)

    Hao, Jianping; Sadaune, Véronique; Burgnies, Ludovic; Lippens, Didier

    2014-07-01

    We show that ferroelectrics-based periodic structure made of BaSrTiO3 (BST) cubes, arrayed onto a metal plate with a thin dielectric spacer film exhibit a dramatic enhancement of absorbance with value close to unity. The enhancement is found around the Mie magnetic resonance of the Ferroelectrics cubes with the backside metal layer stopping any transmitted waves. It also involves quasi-perfect impedance matching resulting in reflection suppression via simultaneous magnetic and electrical activities. In addition, it was shown numerically the existence of a periodicity optimum, which is explained from surface waves analysis along with trade-off between the resonance damping and the intrinsic loss of ferroelectrics cubes. An experimental verification in a hollow waveguide configuration with a good comparison with full-wave numerical modelling is at last reported by measuring the scattering parameters of single and dual BST cubes schemes pointing out coupling effects for densely packed structures.

  19. Heat and mass transfer characteristics of a small helical absorber

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Jung-In [College of Engineering, School of Mechanical Engineering, Pukyong National University, San 100, Yongdang-dong, Nam-gu, Pusan 608-739 (Korea, Republic of); Kwon, Oh-Kyung [KITECH, 35-3 Hongchon-ri, Ipjang-meon, Chonan, Chungnam 330-825 (Korea, Republic of); Bansal, P.K. [Department of Mechanical Engineering, The University of Auckland, Private bag 92019, Auckland (New Zealand); Moon, Choon-Geun; Lee, Ho-Saeng [Department of Refrigeration and Air-conditioning Engineering, Graduate School, Pukyong National University, San 100, Yongdang-dong, Nam-gu, Pusan 608-739 (Korea, Republic of)

    2006-02-01

    This paper presents experimental results of heat and mass transfer investigation of the falling film absorber (with strong lithium bromide solution) for a small household absorption chiller/heater. Various components (e.g. low temperature generator, absorber and evaporator) were arranged concentrically in cylindrical form such that the helical-arrangement of the heat exchangers allowed the system to be more compact than the conventional system. Measurements from the helical absorber were compared with data from the literature. The comparison revealed that the heat and mass transfer performance of the helical absorber tube is similar to the existing tube bundle absorber. As a result, the proposed helical absorber shows a good potential due its reduced size and weight for the future designs of small capacity absorption chillers/heaters. (author)

  20. Liquid Hydrogen Absorber for MICE

    Energy Technology Data Exchange (ETDEWEB)

    Ishimoto, S.; Suzuki, S.; Yoshida, M.; Green, Michael A.; Kuno, Y.; Lau, Wing

    2010-05-30

    Liquid hydrogen absorbers for the Muon Ionization Cooling Experiment (MICE) have been developed, and the first absorber has been tested at KEK. In the preliminary test at KEK we have successfully filled the absorber with {approx}2 liters of liquid hydrogen. The measured hydrogen condensation speed was 2.5 liters/day at 1.0 bar. No hydrogen leakage to vacuum was found between 300 K and 20 K. The MICE experiment includes three AFC (absorber focusing coil) modules, each containing a 21 liter liquid hydrogen absorber made of aluminum. The AFC module has safety windows to separate its vacuum from that of neighboring modules. Liquid hydrogen is supplied from a cryocooler with cooling power 1.5 W at 4.2 K. The first absorber will be assembled in the AFC module and installed in MICE at RAL.

  1. Tunable metamaterial dual-band terahertz absorber

    Science.gov (United States)

    Luo, C. Y.; Li, Z. Z.; Guo, Z. H.; Yue, J.; Luo, Q.; Yao, G.; Ji, J.; Rao, Y. K.; Li, R. K.; Li, D.; Wang, H. X.; Yao, J. Q.; Ling, F. R.

    2015-11-01

    We report a design of a temperature controlled tunable dual band terahertz absorber. The compact single unit cell consists of two nested closed square ring resonators and a layer metallic separated by a substrate strontium titanate (STO) dielectric layer. It is found that the absorber has two distinctive absorption peaks at frequencies 0.096 THz and 0.137 THz, whose peaks are attained 97% and 75%. Cooling the absorber from 400 K to 250 K causes about 25% and 27% shift compared to the resonance frequency of room temperature, when we cooling the temperature to 150 K, we could attained both the two tunabilities exceeding 53%. The frequency tunability is owing to the variation of the dielectric constant of the low-temperature co-fired ceramic (LTCC) substrate. The mechanism of the dual band absorber is attributed to the overlapping of dual resonance frequencies, and could be demonstrated by the distributions of the electric field. The method opens up avenues for designing tunable terahertz devices in detection, imaging, and stealth technology.

  2. 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.

  3. Precise dispersion equations of absorbing filter glasses

    Science.gov (United States)

    Reichel, S.; Biertümpfel, Ralf

    2014-05-01

    The refractive indices versus wavelength of optical transparent glasses are measured at a few wavelengths only. In order to calculate the refractive index at any wavelength, a so-called Sellmeier series is used as an approximation of the wavelength dependent refractive index. Such a Sellmeier representation assumes an absorbing free (= loss less) material. In optical transparent glasses this assumption is valid since the absorption of such transparent glasses is very low. However, optical filter glasses have often a rather high absorbance in certain regions of the spectrum. The exact description of the wavelength dependent function of the refractive index is essential for an optimized design for sophisticated optical applications. Digital cameras use an IR cut filter to ensure good color rendition and image quality. In order to reduce ghost images by reflections and to be nearly angle independent absorbing filter glass is used, e.g. blue glass BG60 from SCHOTT. Nowadays digital cameras improve their performance and so the IR cut filter needs to be improved and thus the accurate knowledge of the refractive index (dispersion) of the used glasses must be known. But absorbing filter glass is not loss less as needed for a Sellmeier representation. In addition it is very difficult to measure it in the absorption region of the filter glass. We have focused a lot of effort on measuring the refractive index at specific wavelength for absorbing filter glass - even in the absorption region. It will be described how to do such a measurement. In addition we estimate the use of a Sellmeier representation for filter glasses. It turns out that in most cases a Sellmeier representation can be used even for absorbing filter glasses. Finally Sellmeier coefficients for the approximation of the refractive index will be given for different filter glasses.

  4. 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 ...

  5. Metamaterial Absorbers for Microwave Detection

    Science.gov (United States)

    2015-06-01

    ABSORBERS FOR MICROWAVE DETECTION by Michael T. McMahan June 2015 Thesis Advisor: Dragoslav Grbovic Co-Advisor: Richard C. Olsen THIS PAGE......presented. 14. SUBJECT TERMS metamaterials, metamaterial absorbers , metamaterial detectors 15. NUMBER OF PAGES 65 16. PRICE

  6. Absorber design in sour natural gas treatment plants: Impact of process variables on operation and economics = Absorberentwurf für Anlagen zur Behandlung von sauren Erdgasen: Einfluss Prozessparameter auf Betriebsführung und Prozesswirtschaftlichkeit

    NARCIS (Netherlands)

    Blauwhoff, P.M.M.; Kamphuis, B.; Swaaij, van W.P.M.; Westerterp, K.R.

    1985-01-01

    Two models of absorber have been developed which describe the absorption of H2S and CO2 from natural gases by aqueous di-isopropanolamine (DIPA) or methyl-di-ethanolamine (MDEA) solutions. In these models mass transfer, reaction and equilibrium processes as they prevail in conventional tray absorber

  7. Leaf absorbance and photosynthesis

    Science.gov (United States)

    Schurer, Kees

    1994-01-01

    The absorption spectrum of a leaf is often thought to contain some clues to the photosynthetic action spectrum of chlorophyll. Of course, absorption of photons is needed for photosynthesis, but the reverse, photosynthesis when there is absorption, is not necessarily true. As a check on the existence of absorption limits we measured spectra for a few different leaves. Two techniques for measuring absorption have been used, viz. the separate determination of the diffuse reflectance and the diffuse transmittance with the leaf at a port of an integrating sphere and the direct determination of the non-absorbed fraction with the leaf in the sphere. In a cross-check both methods yielded the same results for the absorption spectrum. The spectrum of a Fuchsia leaf, covering the short-wave region from 350 to 2500 nm, shows a high absorption in UV, blue and red, the well known dip in the green and a steep fall-off at 700 nm. Absorption drops to virtually zero in the near infrared, with subsequent absorptions, corresponding to the water absorption bands. In more detailed spectra, taken at 5 nm intervals with a 5 nm bandwidth, differences in chlorophyll content show in the different depths of the dip around 550 nm and in a small shift of the absorption edge at 700 nm. Spectra for Geranium (Pelargonium zonale) and Hibiscus (with a higher chlorophyll content) show that the upper limit for photosynthesis can not be much above 700 nm. No evidence, however, is to be seen of a lower limit for photosynthesis and, in fact, some experiments down to 300 nm still did not show a decrease of the absorption although it is well recognized that no photosynthesis results with 300 nm wavelengths.

  8. Flexible subterahertz metamaterial absorber fabrication using inkjet printing technology

    Science.gov (United States)

    Lee, Dongju; Sung, Hyuk-Kee; Lim, Sungjoon

    2016-07-01

    In this study, a flexible metamaterial (MM) absorber was designed at 0.1 THz and fabricated using inkjet printing technology. The unit cell of the MM absorber was designed using a finite element method-based full-wave simulation. The unit cell comprised square rings, and it was printed with silver nanoparticle ink on flexible Kapton polyimide film. The fabrication processes were performed using a material printer. The absorber's reflection coefficient was measured using a vector network analyzer and a WR-10 waveguide. The absorption ratio was 93.5 % at 0.102 THz. Therefore, we demonstrated the possibility of inkjet printing at a subterahertz band.

  9. Improvement on the wave absorbing property of a lossy frequency selective surface absorber using a magnetic substrate

    Institute of Scientific and Technical Information of China (English)

    Sun Liang-Kui; Cheng Hai-Feng; Zhou Yong-Jiang; Wang Jun

    2012-01-01

    An equivalent-circuit model is used to analyse the improvement of the wave absorbing performance of the lossy frequency selective surface(FSS)absorber by using a magnetic substrate,showing that it is possible to widen the wave absorbing bandwidth.Three pieces of magnetic substrates are prepared.According to the complex permittivity and permeability,the reflectivity of the corresponding absorber is calculated by the finite difference time-domain(FDTD)method,and the bandwidth of the reflectivity below-10 dB is optimized by genetic algorithm.The calculated results indicate that the wave absorbing performance is significantly improved by increasing the complex permeability of the substrate; the reflectivity bandwidth below-10 dB of the single layer FSS absorber can reach 3.6-18 GHz with a thickness of 5 mm,which is wider than that with a dielectric substrate.The density of the FSS absorber is only 0.92 g/cm3.Additionally,the absorption band can be further widened by inserting a second lossy FSS.Finally,a double layer lossy FSS absorber with a magnetic substrate is fabricated based on the design result.The experimental result is consistent with the design one.

  10. Absorbent product to absorb fluids. [for collection of human wastes

    Science.gov (United States)

    Dawn, F. S.; Correale, J. V. (Inventor)

    1982-01-01

    A multi-layer absorbent product for use in contact with the skin to absorb fluids is discussed. The product utilizes a water pervious facing layer for contacting the skin, overlayed by a first fibrous wicking layer, the wicking layer preferably being of the one-way variety in which fluid or liquid is moved away from the facing layer. The product further includes a first container section defined by inner and outer layer of a water pervious wicking material between which is disposed a first absorbent mass. A second container section defined by inner and outer layers between which is disposed a second absorbent mass and a liquid impermeable/gas permeable layer. Spacesuit applications are discussed.

  11. Two-dimensional QR-coded metamaterial absorber

    Science.gov (United States)

    Sui, Sai; Ma, Hua; Wang, Jiafu; Pang, Yongqiang; Zhang, Jieqiu; Qu, Shaobo

    2016-01-01

    In this paper, the design of metamaterial absorbers is proposed based on QR coding and topology optimization. Such absorbers look like QR codes and can be recognized by decoding softwares as well as mobile phones. To verify the design, two lightweight wideband absorbers are designed, which can achieve wideband absorption above 90 % in 6.68-19.30 and 7.00-19.70 GHz, respectively. More importantly, polarization-independent absorption over 90 % can be maintained under incident angle within 55°. The QR code absorber not only can achieve wideband absorption, but also can carry information such as texts and Web sites. They are of important values in applications such identification and electromagnetic protection.

  12. Multi-band metamaterial absorber topology for infrared frequency regime

    Science.gov (United States)

    Mulla, Batuhan; Sabah, Cumali

    2017-02-01

    In this paper, a new multiband metamaterial absorber design is proposed and the numerical characterization is carried out. The design is composed of three layers with differently sized quadruplets in which the interaction among them causes the multiband absorption response in the infrared frequency regime. In order to characterize the absorber and explain the multiband topology, some parametric studies with respect to the dimensions of the structure are carried out and the contributions of the quadruplets to the absorption spectrum are analyzed. According to the results, it is found that the proposed metamaterial absorber has five bands in the infrared frequency regime with the absorption levels of: 98.90%, 99.39%, 86.46%, 92.80% and 97.96%. Moreover, the polarization dependency of the structure is examined and it is found that the design operates well as a perfect absorber with polarization independency in the studied frequency range.

  13. An introduction to absorbent dressings.

    Science.gov (United States)

    Jones, Menna Lloyd

    2014-12-01

    Exudate bathes the wound bed with a serous fluid that contains essential components that promote wound healing. However, excess exudate is often seen as a challenge for clinicians. Absorbent dressings are often used to aid in the management of exudate, with the aim of providing a moist but unmacerated environment. With so many different types of absorbent dressings available today-alongside making a holistic assessment-it is essential that clinicians also have the knowledge and skill to select the most appropriate absorbent dressing for a given patient.

  14. Performance evaluation of CFRP-rubber shock absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Lamanna, Giuseppe, E-mail: giuseppe.lamanna@unina2.it; Sepe, Raffaele, E-mail: giuseppe.lamanna@unina2.it [Department of Industrial and Information Engineering, Second University of Naples, via Roma, 29 - 81031 Aversa (Italy)

    2014-05-15

    In the present work a numerical investigation on the energy absorbing capability of dedicated structural components made of a carbon fiber reinforced polymer and an emulsion polymerised styrene butadiene rubber is reported. The shock absorbers are devices designed to absorb large amounts of energy by sacrificing their own structural integrity. Their aim is to cushion the effects of an impact phenomenon with the intent to preserve other structures from global failure or local damaging. Another important role of shock absorbers is reducing the peak of the acceleration showed during an impact phenomenon. This effect is of considerable interest in the case of vehicles to preserve passengers’ safety. Static and dynamic numerical results are compared with experimental ones in terms of mean crushing forces, energy and peak crushing. The global performance of the absorbers has been evaluated by referencing to a proposed quality index.

  15. Tunable THz perfect absorber using graphene-based metamaterials

    Science.gov (United States)

    Faraji, Mahboobeh; Moravvej-Farshi, Mohammad Kazem; Yousefi, Leila

    2015-11-01

    A tunable THz absorber, with absorbance more than 90% is proposed, and numerically characterized. The absorber structure is based on metamaterials with unit cells consisting of two patterned graphene layers separated by a 5-nm thick layer of Al2O3. Numerical results show that when the chemical potential of the top graphene microribbons are tuned by an external variable bias and that of the lower graphene fishnet is kept at μC=0, frequency of the absorption peaks can be tuned as desired, therefore we can have a tunable or switchable absorber. The proposed absorber can have applications in designing tunable reflective THz filters or tunable THz switches and modulators. It can also be used for cloaking objects in THz range.

  16. 均匀设计法优化一种高吸水性树脂的制备工艺%Optimal preparation of a type of super absorbent resin using uniform design

    Institute of Scientific and Technical Information of China (English)

    苏秀霞; 耿肖沙; 李仲谨; 杨玉娜

    2012-01-01

    A super absorbent resin,xanthan gum-g-poly(acrylic acid-co-2-acrylanido-2-methlpropanesulfonic acid)[XG/P(AA-AMPS)],was prepared by solution polymerization in this study.The synthesis process was optimized by using U10 *(104)uniform design.The results showed that the best weight ratio of acrylic acid is 12 g,the amount of initiator is 0.5%,the neutralization degree of acrylic acid is 80% and the synthesis temperature of graft copolymerization is 60 ℃.Under the optimal condition of absorbent resin synthesizing,the water absorption multiple is up to 997.1 g/g,with normal saline is up to 176.2 g/g.The fourier infrared spectroscopy(FTIR),scanning electron microscopy(SEM) and integrated thermal analyzers were used for the characterization of the super absorbent resin.The results of FTIR characterization show that acrylic acid(AA)and 2-acrylanido-2-methlpropanesulfonic acid(AMPS)are grafted to the molecular chain of xanthan gum,and the SEM observation results showed that the resin forms a porous network structure.The thermal performance analysis results show that the resin has good thermal stability at high temperature.%采用水溶液聚合的方法制备了黄原胶接枝丙烯酸/2-丙烯酰胺基-2-甲基丙磺酸[XG/P(AA-AMPS)]高吸水树脂。采用U10*(104)均匀设计对合成工艺进行优化,得出最佳合成条件为丙烯酸用量12 g、引发剂用量为单体总量的0.5%、丙烯酸的中和度为80%、聚合反应温度60℃。最佳合成条件下制备的高吸水性树脂吸水倍率达997.1 g/g,吸生理盐水倍率为176.2 g/g。采用傅里叶红外光谱(FTIR)、扫描电镜(SEM)和综合热分析仪对高吸水树脂进行表征。红外光谱分析结果显示丙烯酸(AA)和2-丙烯酰胺基-2-甲基丙磺酸(AMPS)已接枝到黄原胶分子链上,扫描电镜观察结果显示树脂形成一种多孔性网络结构,热性能分析结果显示树脂在高温下具有良好的热稳定性。

  17. Spontaneous emission and absorber theory

    Science.gov (United States)

    Pegg, David T.

    1997-01-01

    One of the long term interests of George Series was the construction of a theory of spontaneous emission which does not involve field quantisation. His approach was written in terms of atomic operators only and he drew a parallel with the Wheeler-Feynman absorber theory of radiation. By making a particular extra postulate, he was able to obtain the correct spontaneous emission rate and the Lamb shift reasonably simply and directly. An examination of his approach indicates that this postulate is physically reasonable and the need for it arises because quantisation in his theory occurs after the response of the absorber has been accounted for by means of the radiative reaction field. We review briefly an alternative absorber theory approach to spontaneous emission based on the direct action between the emitting atom and a quantised absorber, and outline some applications to more recent effects of interest in quantum optics.

  18. Broadband fast semiconductor saturable absorber.

    Science.gov (United States)

    Jacobovitz-Veselka, G R; Kellerm, U; Asom, T

    1992-12-15

    Kerr lens mode-locked (KLM) solid-state lasers are typically not self-starting. We address this problem by introducing a broadband semiconductor saturable absorber that could be used as a tunable, all-solid-state, passive starting mechanism. We extend the wavelength tunability of a semiconductor saturable absorber to more than 100 nm using a band-gap-engineered low-temperature molecular-beam-epitaxy (MBE)-grown bulk AlGaAs semiconductor saturable absorber in which the absorption edge of the saturable absorber has been artificially broadened by continuously reducing the Al concentration during the MBE growth. We demonstrate its tunability and its feasibility as a starting mechanism for KLM with a picosecond resonant passive mode-locked Ti:sapphire laser. The extension to femtosecond KLM lasers has been discussed previously.

  19. Guided tissue regeneration. Absorbable barriers.

    Science.gov (United States)

    Wang, H L; MacNeil, R L

    1998-07-01

    Over the past 15 years, techniques aimed at regeneration of lost periodontal tissue have become widely used and accepted in clinical practice. Among these techniques are those which use the principles of guided tissue regeneration (GTR), wherein barriers (i.e., membranes) are used to control cell and tissue repopulation of the periodontal wound. A variety of non-absorbable and absorbable barriers have been developed and used for this purpose, with a trend in recent years toward increased use of absorbable GTR materials. This article describes the evolution of absorbable barrier materials and overview materials available for clinical use today. In addition, advantages and disadvantages of these materials are discussed, as well as possible new developments in barrier-based GTR therapy.

  20. Optimization of the acoustic absorption coefficients of certain functional absorbents

    Science.gov (United States)

    Pocsa, V.; Biborosch, L.; Veres, A.; Halpert, E.; Lorian, R.; Botos, T.

    1974-01-01

    The sound absorption coefficients of some functional absorbents (mineral wool plates) are determined by the reverberation chamber method. The influence of the angle of inclination of the sound absorbing material with respect to the surface to be treated is analyzed as well as the influence of the covering index, defined as the ratio of the designed area of a plate and the area of the treated surface belonging to another plate. As compared with the conventional method of applying sound-absorbing plates, the analyzed structures have a higher technological and economical efficiency. The optimum structure corresponds to an angle of inclination of 15 deg and a covering index of 0.8.

  1. Energy deposition studies for the LBNE beam absorber

    CERN Document Server

    Rakhno, Igor L; 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.

  2. Study of an electroacoustic absorber

    OpenAIRE

    Rodríguez de Antonio, Javier

    2008-01-01

    El problema de la atenuación del ruido de baja frecuencia todavía persiste pese a que ha sido ampliamente estudiado. Las técnicas para absorber ruido de alta frecuencia (superior a 500 Hz), como son los materiales porosos, resonadores de Helmholtz o espumas no ofrecen resultados aceptables a bajas frecuencias. Serían necesarios volúmenes impracticables de materiales porosos para intentar absorber frecuencias menores a 500 Hz, y lo mismo ocurre con los resonadores de Helmholtz. Esta ineficacia...

  3. Waveform-dependent absorbing metasurfaces

    CERN Document Server

    Wakatsuchi, Hiroki; Rushton, Jeremiah J; Sievenpiper, Daniel F

    2014-01-01

    We present the first use of a waveform-dependent absorbing metasurface for high-power pulsed surface currents. The new type of nonlinear metasurface, composed of circuit elements including diodes, is capable of storing high power pulse energy to dissipate it between pulses, while allowing propagation of small signals. Interestingly, the absorbing performance varies for high power pulses but not for high power continuous waves (CWs), since the capacitors used are fully charged up. Thus, the waveform dependence enables us to distinguish various signal types (i.e. CW or pulse) even at the same frequency, which potentially creates new kinds of microwave technologies and applications.

  4. Effect of Slag on Burnability Cement Raw Meal Containing Silica Crystals%矿渣对煅烧含高结晶态SiO2水泥生料的影响

    Institute of Scientific and Technical Information of China (English)

    艾红梅; 卢普光; 白军营; 卢洪正

    2012-01-01

    The burnability of raw materials and the quality of clinkers can be affected while too much quartz in raw material. Quartz will be brought in raw materials inevitably while the all components of waste concrete were used in cement production. Different proportions of slag were mixed in raw material in the experiment, the effect of slag on the clinker property and the burnability of raw material whose silicon materials were ISO standard sand was studied. The ethanol-glycol method was used to analyze the content of f-CaO, clinker minerals were identified by XRD, mineral morphology was observed by metalloscope, cement paste specimen were produced to test the compressive strength of hydrated clinker. The result showed that the burnability of raw materials with high quartz content was notably improved while adding the slag, slag also improved the formation of clinker mineral, while the amount of slag in raw materials was 3% ,hydrated clinker has the highest comprehensive strength; clinker produced more C-S-H gel and AFt in early hydration and C-S-H gel can be much denser in late hydration while moderate slag added in the raw materials.%利用含砂废弃混凝土原料煅烧水泥熟料,不可避免地会由细骨料砂引入结晶度较高的结晶态SiO2,不仅影响生料易烧性,而且影响硅酸盐矿物的组成和形貌,降低熟料质量.以ISO标准砂为硅质原料配制高结晶态SiO2含量的生料,按不同比例掺入矿渣,煅烧至不同温度;利用化学分析、XRD、岩相分析、SEM等方法,研究矿渣对水泥生料易烧性、熟料矿物组成和显微结构、熟料水化强度发展及水化产物形貌的影响.结果表明,适量矿渣的掺入可显著改善高结晶态SiO2含量水泥生料的易烧性,促进熟料矿物形成和发育;矿渣掺量为3%时,熟料水化后强度最高;适量矿渣可使熟料水化早期产生较多的C-S-H凝胶和钙矾石,而后期水化产物中C-S-H凝胶更密实,提高水泥强度.

  5. A novel broadband waterborne acoustic absorber

    Science.gov (United States)

    Wang, Changxian; Wen, Weibin; Huang, Yixing; Chen, Mingji; Lei, Hongshuai; Fang, Daining

    2016-07-01

    In this paper, we extended the ray tracing theory in polar coordinate system, and originally proposed the Snell-Descartes law in polar coordinates. Based on these theories, a novel broadband waterborne acoustic absorber device was proposed. This device is designed with gradient-distributing materials along radius, which makes the incidence acoustic wave ray warps. The echo reduction effects of this device were investigated by finite element analysis, and the numerical results show that the reflectivity of acoustic wave for the new device is lower than that of homogenous and Alberich layers in almost all frequency 0-30 kHz at the same loss factor.

  6. 基于动力吸振理论的车辆ISD悬架设计与性能分析%Design and Performances Analysis of Vehicle ISD Suspension Based on Dynamic Vibration Absorber Theory

    Institute of Scientific and Technical Information of China (English)

    杨晓峰; 沈钰杰; 陈龙; 汪若尘; 孙晓强

    2014-01-01

    ISD( inerter-spring-damper)悬架是由惯容器、弹簧和阻尼器构成的一种新型车辆被动悬架。本文中基于动力吸振器在振动控制中的作用,利用惯容器动力学特性,建立了ISD悬架的单轮模型,设计出含有动力吸振器结构的ISD悬架,并对其进行仿真,用多目标遗传算法确定元件参数,分析ISD悬架的主频率特性和各性能指标(车身加速度、悬架动行程和轮胎动载荷)的振动传递特性。仿真结果表明,在0~15Hz低频段,与等刚度的传统被动悬架相比,ISD悬架改善了各性能指标的振动传递幅频特性,降低了各性能指标在共振频率1Hz附近的功率谱密度峰值。%Inerter-spring-damper( ISD) suspension is a new type of vehicle passive suspension, consisting of inerter, spring and damper. In this paper, based on the role of dynamic vibration absorber( DVA) in vibration con-trol, and by utilizing the dynamic characteristics of inerter, a single wheel model for ISD suspension is built and an ISD suspension incorporating the structure of DVA is designed. Then a simulation on ISD suspension is conducted, in which the parameters of its components are determined with multi-objective genetic algorithm, and its main fre-quency characteristics and the vibration transmission characteristics for all three performance indicators( vehicle body acceleration, suspension dynamic travel and dynamic tire load) are analyzed. Simulation results show that compared with traditional passive suspension with same stiffness, the amplitude-frequency characteristics of vibration transmis-sion for all suspension performance indicators are improved at low frequency range of 0 ~15Hz, and the peaks of power spectral density for all performance indicators are reduced effectively at resonance frequency near 1Hz.

  7. Oil and fat absorbing polymers

    Science.gov (United States)

    Marsh, H. E., Jr. (Inventor)

    1977-01-01

    A method is described for forming a solid network polymer having a minimal amount of crosslinking for use in absorbing fats and oils. The polymer remains solid at a swelling ratio in oil or fat of at least ten and provides an oil absorption greater than 900 weight percent.

  8. Stretchable Metamaterial Absorber Using Liquid Metal-Filled Polydimethylsiloxane (PDMS

    Directory of Open Access Journals (Sweden)

    Kyeongseob Kim

    2016-04-01

    Full Text Available A stretchable metamaterial absorber is proposed in this study. The stretchability was achieved by liquid metal and polydimethylsiloxane (PDMS. To inject liquid metal, microfluidic channels were fabricated using PDMS powers and microfluidic-channel frames, which were built using a three-dimensional printer. A top conductive pattern and ground plane were designed after considering the easy injection of liquid metal. The proposed metamaterial absorber comprises three layers of PDMS substrate. The top layer is for the top conductive pattern, and the bottom layer is for the meandered ground plane. Flat PDMS layers were inserted between the top and bottom PDMS layers. The measured absorptivity of the fabricated absorber was 97.8% at 18.5 GHz, and the absorption frequency increased from 18.5 to 18.65 GHz as the absorber was stretched from its original length (5.2 cm to 6.4 cm.

  9. Calculations in the Wheeler-Feynman Absorber Theory of Radiation.

    Science.gov (United States)

    Balaji, Kalathur Sreenivasan

    One dimensional computer aided calculations were done to find the self-consistent solutions for various absorber configurations in the context of the Wheeler-Feynman Absorber theory, wherein every accelerating charge is assumed to produce a time symmetric combination of advanced and retarded fields. These calculations picked out the so called "outerface" solution for incomplete absorbers and showed that advanced as well as retarded signals interact with matter in the same manner as in the full retarded theory. Based on these calculations the Partridge experiment and the Schmidt-Newman experiment were ruled out as tests of the Absorber theory. An experiment designed to produce and detect advanced effects is proposed, based on more one-dimensional calculations.

  10. Calculations in the Wheeler-Feynman absorber theory of radiation

    Energy Technology Data Exchange (ETDEWEB)

    Balaji, K.S.

    1986-01-01

    One dimensional computer aided calculations were done to find the self consistent solutions for various absorber configurations in the context of the Wheeler-Feynman absorber theory, wherein every accelerating charge is assumed to produce a time symmetric combination of advanced and retarded fields. These calculations picked out the so called outerface solution for incomplete absorbers and showed that advanced as well as retarded signals interact with matter in the same manner as in the full retarded theory. Based on these calculations, the Partridge experiment and the Schmidt-Newman experiment were ruled out as tests of the absorber theory. An experiment designed to produce and detect advanced effects is proposed, based on more one-dimensional calculations.

  11. The rat bowel of β-asaron absorbs the research

    Institute of Scientific and Technical Information of China (English)

    QI Yue; JIA Dong; YOU Xian-min; ZOU Gui-xin; JIANG Hong

    2008-01-01

    Objective Study the β-asaron under the condition that the bowel each segment of rat and be worth in the diffent medicine density and pH of the absorption dynamics characteristic, as to it's the rat absorbs the part in the body and it absorbs the mechanism to carry on the study, for the further design β-asaron settle release the product to provide the living creature medicine learn the basis. Methods Apply the rat to the body to infuse to flow the bowel absorption experiment investigation and absorption dynamics characteristic;adopt the HPLC method measurement β-asaron is in rat body the bowel absorbs the medicine density within the reflux liquid. Results It absorb the quantity and β-asaron of the medicine in the reflux liquid, the density of β-asaron becomes the direct proption, the absorption speed constant of the medicine is basic and constant within the scope of the 19 μg·mL-1- 57 μg·mL-1; In the pH is 5.6; 6.9; 8.0 three kinds of dissimilarities lie the absorption velocity constant of the quality and absorb the of percentage and also did not show the difference of salience;β-asaron is in the small intestines the lower part absorb better, absorbthe velocity to press to return to bowel, ileum, jejunum, duodenum, colon to descend one by one in order, absorb the velocity constant one by one in order is 0.402, 0.396, 0.385, 0.325 h-1. Conclusions β-asaron absorbs to present a class absorption dynamics characteristic in the bowel way, absorbing the mechanism as passive absorption; in order to return to ileum and jejunums, main absorption part there is certain absorption in the colon, too.

  12. Graphene induced tunable and polarization-insensitive broadband metamaterial absorber

    Science.gov (United States)

    Zhang, Yuping; Li, Yue; Cao, Yanyan; Liu, Yuanzhong; Zhang, Huiyun

    2017-01-01

    We design a tunable and broadband metamaterial absorber in the mid-infrared region based on graphene. The unit cell of the proposed metamaterial absorber consists of circular gold patches, which coupled with a graphene layer, and are separated by a dielectric spacer from the gold film on the bottom. The absorption bandwidth is effectively extended by patterning multi-circular gold patches of different dimension elements with appropriate geometrical parameters in a co-plane. The metamaterial absorber achieves its frequency tunable characteristics via changing the applied voltage or chemical doping to manipulate graphene's Fermi energy. We analyzed the surface current distributions and the distributions of the z-component electric field for understanding the absorption mechanism. Moreover, the design principle here could be regarded as a template to extend bandwidth by introducing more circular patches into each unit cell. Our design has potential applications in various fields of stealth technology, photovoltaic devices, sensors, and broadband communication.

  13. Using burnability index to control the burning temperature of rotary kiln%用生料易烧性指数控制回转窑煅烧温度

    Institute of Scientific and Technical Information of China (English)

    袁慧芳; 刘福东; 刘志刚; 杨克锐; 魏庆敏

    2001-01-01

    研究了带余热发电回转窑窑灰对熟料煅烧的影响,结果表明,窑灰的掺入对生料的易烧性和回转窑的煅烧有很大的影响,其中存在一个最佳掺入量。应该严格控制窑灰的加入量,才能保证窑的优质高产。生料的煅烧温度与其易烧性有直接的关系,在设备条件一定的情况下,可以用易烧性来控制窑的煅烧温度。%Influences of rotary kiln dust on clinker burning are investigated in this paper,which is a sub-project of Tangshan mechatronics project-cement synthetical intelligent automatic system.The results show that adding of rotary kiln dust affects both burnabiliy of raw mix and burning of rotary kiln strongly and a best adding amount exists.Adding amount of kiln dust must be controlled strictly to keep the kiln operating well.The burning temperature of raw mix has direct relations with its burnatiliy.Under the same device conditions,using burnability index can control burning temperature of the kiln.

  14. Side branch absorber for exhaust manifold of two-stroke internal combustion engine

    Energy Technology Data Exchange (ETDEWEB)

    Harris, Ralph E. (San Antonio, TX); Broerman, III, Eugene L. (San Antonio, TX); Bourn, Gary D. (Laramie, WY)

    2011-01-11

    A method of improving scavenging operation of a two-stroke internal combustion engine. The exhaust pressure of the engine is analyzed to determine if there is a pulsation frequency. Acoustic modeling is used to design an absorber. An appropriately designed side branch absorber may be attached to the exhaust manifold.

  15. Insight into magnetorheological shock absorbers

    CERN Document Server

    Gołdasz, Janusz

    2015-01-01

    This book deals with magnetorheological fluid theory, modeling and applications of automotive magnetorheological dampers. On the theoretical side a review of MR fluid compositions and key factors affecting the characteristics of these fluids is followed by a description of existing applications in the area of vibration isolation and flow-mode shock absorbers in particular. As a majority of existing magnetorheological devices operates in a so-called flow mode a critical review is carried out in that regard. Specifically, the authors highlight common configurations of flow-mode magnetorheological shock absorbers, or so-called MR dampers that have been considered by the automotive industry for controlled chassis applications. The authors focus on single-tube dampers utilizing a piston assembly with one coil or multiple coils and at least one annular flow channel in the piston.

  16. Optimum thickness of Mossbauer absorber

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    If recoilless fraction fa is available, the optimum absorber thickness dopt can be calculated by maximizing the signal to noise ratio or Q factor. In this work,an approach presented is to get experimental Qexp as a function of the thickness, and then fitting Qexp by its theoretical expression gives fa value. At last the dopt value is deduced from a maximum on the fitted curve. In such a way, thicknesses of six specimens with quadrupole or magnetic hyperfine splitting were optimized.

  17. Control system design for the deethanizer absorber tower pressure in the light end unit of the Nico Lopez refinery; Diseno del sistema de control para la presion en la torre absorvedora deetanizadora de la unidad de finales ligeros de la refineria Nico Lopez

    Energy Technology Data Exchange (ETDEWEB)

    Morales Corral, Camilo [Refineria Nico Lopez, Ciudad Habana (Cuba)]. E-mail: Camilo.morales@refhab.cupet.cu; Pedre Mendoza, Isabel [DAISA, Ciudad Habana (Cuba)]. E-mail: Isabel@daisa.copextel.com.cu; Garcini Leal, Hector J. [Instituto Superior Politecnico Jose A. Echeverria, La Habana (Cuba)]. E-mail: garcini,novi@electrica.cujae.edu.cu; Fernandez, Luis M. [Instituto de Cibernetica, Matematica y Fisica, La Habana (Cuba)]. E-mail: luis@icmf.inf.cu; Benitez Gonzalez, Ivon Oristela [Instituto Superior Politecnico Jose A. Echeverria, La Habana (Cuba)

    2010-11-15

    This paper is about pressure feed forward control. It is for an absorber tower of the Light End Unit. This one is in the Havana Oil Refinery. Control loop was designed using identification technic and simulation software. Moreover the design control loop has been validated and his quality has been determined. [Spanish] En el presente trabajo se aborda un control anticipatorio de presion. Fue desarrollado para la torre absorvedora de la Unidad de Finales Ligeros. La cual pertenece a la refineria de La Habana. Fue disenado un lazo de control empleando tecnicas de identificacion y programas de simulacion. Ademas el lazo disenado es validado y se determina su calidad.

  18. Ammonia-water absorption in vertical tubular absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Seara, Jose; Sieres, Jaime; Rodriguez, Cristobal; Vazquez, Manuel [Area de Maquinas y Motores Termicos, Escuela Tecnica Superior de Ingenieros Industriales, Campus Lagoas-Marcosende, No 9, 36200 Vigo (Spain)

    2005-03-01

    This paper presents a detailed analysis of the heat and mass transfer processes during the absorption of ammonia into water in a co-current vertical tubular absorber. The absorber configuration is of the shell and tubes type. The absorption process progresses as the vapour and liquid contact inside the tubes. Water is used as the absorber cooling medium. A differential mathematical model has been developed on the basis of mass and energy balances and heat and mass transfer equations, in order to provide further understanding of the absorber behaviour. The model takes into account separately for the churn, slug and bubbly flow patterns experimentally forecasted in this type of absorption processes inside vertical tubes and considers the simultaneous heat and mass transfer processes in both liquid and vapour phases, as well as heat transfer to the cooling medium. The model equations have been solved using the finite-difference method. Results obtained for specific data are depicted to show local values of the most important variables all along the absorber length. Parametric analyses have been performed to show the influence of design parameters and operating conditions on the absorber performance. The effect of the heat and mass transfer coefficients has also been evaluated. (authors)

  19. Absorber Model for CO2 Capture by Monoethanolamine

    DEFF Research Database (Denmark)

    Faramarzi, Leila; Kontogeorgis, Georgios; Michelsen, Michael Locht

    2010-01-01

    The rate-based steady-state model proposed by Gabrielsen et al. (Gabrielsen, J.; Michelsen, M. L.; Kontogeorgis, G. M.; Stenby, E. H. AIChE J. 2006, 52, 10, 3443-3451) for the design of the CO2-2-amino-2-methylpropanol absorbers is adopted and improved for the design of the CO2-monoethanolamine...... absorber. The influence of the application of different mass transfer correlations on the model's performance is investigated. Analytical expressions for the calculation of the enhancement factor for the second order as well as the pseudo-first-order reaction regime are integrated in the model......, and their impact on the model's prediction is compared. The model has been successfully applied to CO2 absorber packed columns and validated against pilot plant data with good agreement....

  20. Tunable multichannel absorber composed of graphene and doped periodic structures

    Science.gov (United States)

    Kong, Xiang-kun; Shi, Xiang-zhu; Mo, Jin-jun; Fang, Yun-tuan; Chen, Xin-lei; Liu, Shao-bin

    2017-01-01

    A new design for a tunable multichannel compact absorber, which is achieved by using an asymmetric photonic crystal with graphene monolayers, is theoretically proposed. The graphene monolayers are periodically embedded into the first and last dielectric layers. The absorption, reflection, and transmission spectra of the absorber are studied numerically. A perfect absorption channel is achieved because of impedance matching, and channel number can be modulated by changing periodic number. The characteristic properties of the absorption channel depend on graphene conductivity, which can be controlled via the gate voltage. The proposed structure works as a perfect absorber that is independent from polarization. It has potential applications in the design of multichannel filters, thermal detectors, and electromagnetic wave energy collectors.

  1. Broadband terahertz metamaterial absorber based on sectional asymmetric structures

    Science.gov (United States)

    Gong, Cheng; Zhan, Mingzhou; Yang, Jing; Wang, Zhigang; Liu, Haitao; Zhao, Yuejin; Liu, Weiwei

    2016-01-01

    We suggest and demonstrate the concept and design of sectional asymmetric structures which can manipulate the metamaterial absorber’s working bandwidth with maintaining the other inherent advantages. As an example, a broadband terahertz perfect absorber is designed to confirm its effectiveness. The absorber’s each cell integrates four sectional asymmetric rings, and the entire structure composed of Au and Si3N4 is only 1.9 μm thick. The simulation results show the bandwidth with absorptivity being larger than 90% is extended by about 2.8 times comparing with the conventional square ring absorber. The composable small cell, ultra-thin, and broadband absorption with polarization and incident angle insensitivity will make the absorber suitable for the applications of focal plane array terahertz imaging. PMID:27571941

  2. New resonant cavity-enhanced absorber structures for mid-infrared detector application

    CERN Document Server

    Zohar, Moshe; Faraone, Lorenzo; Hava, Shlomo

    2012-01-01

    A new dielectric Fabry-Perot cavity was designed for a resonant enhancing optical absorption by a thin absorber layer embedded into the cavity. In this cavity, the front mirror is a subwavelength grating with $\\sim 100$% retroreflection. For a HgCdTe absorber in a matching cavity of the new type, the design is shown to meet the combined challenges of increasing the absorbing efficiency of the entire device up to $\\sim 100$% and reducing its size and overall complexity, compared to a conventional resonant cavity enhanced HgCdTe absorber, while maintaining a fairly good tolerance against the grating's fabrication errors.

  3. Plasmonic titanium nitride nanostructures for perfect absorbers

    DEFF Research Database (Denmark)

    Guler, Urcan; Li, Wen-Wei; Kinsey, Nathaniel

    2013-01-01

    We propose a metamaterial based perfect absorber in the visible region, and investigate the performance of titanium nitride as an alternative plasmonic material. Numerical and experimental results reveal that titanium nitride performs better than gold as a plasmonic absorbing material...

  4. Acoustical model of a Shoddy fibre absorber

    Science.gov (United States)

    Manning, John Peter

    Shoddy fibres or "Shoddies" are a mixture of post-consumer and post-industrial fibres diverted from textile waste streams and recycled into their raw fibre form. They have found widespread use as a raw material for manufacturing sound absorbers that include, but are not limited to: automotive, architectural and home appliance applications. The purpose of this project is to develop a simple acoustic model to describe the acoustic behaviour of sound absorbers composed primarily of Shoddy fibres. The model requires knowledge of the material's bulk density only. To date, these materials have not been the focus of much published research and acoustical designers must rely on models that were developed for other materials or are overly complex. For modelling purposes, an equivalent fluid approach is chosen to balance complexity and accuracy. In deriving the proposed model, several popular equivalent fluid models are selected and the required input parameters for each model identified. The models are: the model of Delaney and Bazley, two models by Miki, the model of Johnson in conjunction with the model of Champoux and Allard and the model of Johnson in conjunction with the model of Lafarge. Characterization testing is carried out on sets of Shoddy absorbers produced using three different manufacturing methods. The measured properties are open porosity, tortuosity, airflow resistivity, the viscous and thermal characteristic lengths and the static thermal permeability. Empirical relationships between model parameters and bulk density are then derived and used to populate the selected models. This yields several 'simplified' models with bulk density as the only parameter. The most accurate model is then selected by comparing each model's prediction to the results of normal incidence sound absorption tests. The model of Johnson-Lafarge populated with the empirical relations is the most accurate model over the range of frequencies considered (approx. 300 Hz - 4000 Hz

  5. Optimally tuned vibration absorbers to control sound transmission

    Science.gov (United States)

    Grissom, Michael; Belegundu, Ashok; Koopmann, Gary

    2002-05-01

    A design optimization method is proposed for controlling broadband vibration of a structure and it concomitant acoustic radiation using multiple-tuned absorbers. A computationally efficient model of a structure is developed and coupled with a nonlinear optimization search algorithm. The eigenvectors of the original structure are used as repeated basis functions in the analysis of the structural dynamic re-analysis problem. The re-analysis time for acoustic power computations is reduced by calculating and storing modal radiation resistance matrices at discrete frequencies. The matrices are then interpolated within the optimization loop for eigenvalues that fall between stored frequencies. The method is demonstrated by applying multiple-tuned vibration absorbers to an acoustically-excited composite panel. The absorber parameters are optimized with an objective of maximizing the panel's sound power transmission loss. It is shown that in some cases the optimal solution includes vibration absorbers that are tuned very closely in frequency, thus acting effectively as a broadband vibration absorber (BBVA). The numerical model and design optimization method are validated experimentally, and the BBVA is found to be an effective noise abatement tool.

  6. An Energy Absorber with Force Modificator

    Institute of Scientific and Technical Information of China (English)

    SU Hao; ZHANG Xiaowei; YU Tongxi

    2006-01-01

    Thin-walled tubes are extensively applied in engineering,especially in vehicle structures to resist axial or traversal impact loads,for their excellent energy absorbing capacity.However,in the axial deformation mode,the force history has an extremely high peak force which may bring not only fatal injury to occupants but also damage to structures,cargo and environment.Aiming to develop energy absorbers with impact-force modificator,square metal tube with force modificator is investigated which can monitor the force-deformation history of the tube.A small device is designed to serve as an impact-force modificator,which introduces desired imperfections to the square tube just before the impact happens between the impactor and the tube,so as to reduce the peak force.Prototypes with various governing parameters were manufactured and tested both quasi-statically and dynamically to study the effects of these parameters on the characteristics of energy absorption.The results show that the force modificator can achieve the desired reduction of the peak force well whilst remaining the specific energy absorption capacity of the original square tube.With future improvements,it could be applied to vehicles or roadside safety hardware to mitigate the consequences produced by traffic accidents.

  7. Remarks on Wheeler-Feynman absorber theory

    OpenAIRE

    Gründler, Gerold

    2014-01-01

    The derivation of absorber theory is outlined in very detail. Absorber theory is based on classical action-at-a-distance electrodynamics, but it deviates from that theory at a crucial point. It is shown that (a) absorber theory cannot achieve any of it's essential results without this deviation, and that (b) this deviation restricts the application range of absorber theory to stationary radiation processes. Furthermore an error which crept into Wheeler's and Feynman's interpretation of their ...

  8. Flexible metamaterial absorbers for stealth applications at terahertz frequencies

    DEFF Research Database (Denmark)

    Iwaszczuk, Krzysztof; Strikwerda, Andrew; Fan, K.

    2012-01-01

    We have wrapped metallic cylinders with strongly absorbing metamaterials. These resonant structures, which are patterned on flexible substrates, smoothly coat the cylinder and give it an electromagnetic response designed to minimize its radar cross section. We compare the normal-incidence, small...

  9. Porcelain enamel neutron absorbing material

    Science.gov (United States)

    Iverson, Daniel C.

    1990-01-01

    A porcelain enamel composition as a neutron absorbing material can be prepared of a major proportion by weight of a cadmium compound and a minor proportion of compounds of boron, lithium and silicon. These compounds in the form of a porcelain enamel coating or layer on several alloys has been found to be particularly effective in enhancing the nuclear safety of equipment for use in the processing and storage of fissile material. The composition of the porcelain enamel coating can be tailored to match the coefficient of thermal expansion of the equipment to be coated and excellent coating adhesion can be achieved.

  10. Analysis and evaluation of RF absorbing material in suppressing modes associated with a metallic cavity

    Science.gov (United States)

    Green, David L.

    Application of absorbing materials within enclosures designed to house high-speed digital electronics has become common practice for suppressing resonances associated with the enclosure geometry. Use of absorbing material is often considered toward the end of the design phase when the product is undergoing electromagnetic compatibility compliance testing, leaving little time for the additional experimentation required to optimize absorber material selection or placement within the device. The engineering principles required for maximizing absorber performance within the enclosure are often disregarded, replaced by a "shotgun" approach where multiple material options are experimented with until a solution is achieved. For this research a frequency domain reverberation chamber technique and one-port time domain quality factor estimation technique are employed to quantify the ability of various absorbing materials to suppress resonances of a physically small, electrically large cavity representative of those that may be used to enclose high-speed circuitry. Using both measurement techniques, assessment of the performance of various absorbing materials was performed as well as an evaluation of the affect absorber position has on overall material performance. It was found that both measurement techniques were effective in quantifying absorber performance within the cavity. For the frequency domain reverberation chamber approach the absorber effectiveness, defined as the difference in insertion loss between the cavity with and without absorbing material, was analyzed for various materials. For the undermoded cavity it was found that absorber effectiveness was positionally dependent. For the overmoded cavity, however, the position of the absorber within the cavity, as long as the total exposed surface area remained constant, did not have a significant impact on the absorber effectiveness. Similar results were also found by comparing the estimated quality factor for

  11. Theoretical analysis of the acoustical characteristics of suspended micro-perforated panel absorbers

    Institute of Scientific and Technical Information of China (English)

    SHENG Shengwo; SONG Yongmin; WANG Jiqing

    2005-01-01

    Sound absorption characteristics of suspended micro-perforated panel absorbers were investigated theoretically. The method of half thickness model of such panel absorber with quadripole analysis was used for predicting its acoustic performance. The analysis results show that the predictions agree well with the measurements of absorption in the reverberation chamber. The factors affecting the absorption characteristics for such absorbers were discussed,and some rules as design guidelines were given.

  12. Carbon dioxide absorbents for rebreather diving.

    Science.gov (United States)

    Pennefather, John

    2016-09-01

    Firstly I would like to thank SPUMS members for making me a Life Member of SPUMS; I was surprised and greatly honoured by the award. I also want to confirm and expand on the findings on carbon dioxide absorbents reported by David Harvey et al. For about 35 years, I was the main player in deciding which absorbent went into Australian Navy and Army diving sets. On several occasions, suppliers of absorbents to the anaesthesia market tried to supply the Australian military market. On no occasion did they provide absorbent that came close to the minimum absorbent capacity required, generally being 30-40% less efficient than diving-grade absorbents. Because I regard lives as being more important than any likely dollar saving, the best absorbent was always selected unless two suppliers provided samples with the same absorbent capacity. On almost every occasion, there was a clear winner and cost was never considered. I suggest the same argument for the best absorbent should be used by members and their friends who dive using rebreather sets. I make this point because of my findings on a set that was brought to me after the death of its owner. The absorbent was not the type or grain size recommended by the manufacturer of the set and did not resemble any of the diving grade absorbents I knew of. I suspected by its appearance that it was anaesthetic grade absorbent. When I tested the set, the absorbent system failed very quickly so it is likely that carbon dioxide toxicity contributed to his death. The death was not the subject of an inquest and I have no knowledge of how the man obtained the absorbent. Possibly there was someone from an operating theatre staff who unintentionally caused their friend's death by supplying him with 'borrowed absorbent'. I make this point as I would like to discourage members from making a similar error.

  13. Remarks on Wheeler-Feynman absorber theory

    CERN Document Server

    Gründler, Gerold

    2015-01-01

    The derivation of absorber theory is outlined in very detail. Absorber theory is based on classical action-at-a-distance electrodynamics, but it deviates from that theory at a crucial point. It is shown that (a) absorber theory cannot achieve any of it's essential results without this deviation, and that (b) this deviation restricts the application range of absorber theory to stationary radiation processes. Furthermore an error which crept into Wheeler's and Feynman's interpretation of their equation (19) is pointed out. These shortcomings can probably be eliminated by a quantum-theoretical formulation of absorber theory.

  14. Skin interaction with absorbent hygiene products.

    Science.gov (United States)

    Runeman, Bo

    2008-01-01

    Skin problems due to the use of absorbent hygiene products, such as diapers, incontinence pads, and feminine sanitary articles, are mostly due to climate or chafing discomfort. If these conditions are allowed to prevail, these may develop into an irritant contact dermatitis and eventually superficial skin infections. Skin humidity and aging skin are among the most significant predisposing and aggravating factors for dermatitis development. Improved product design features are believed to explain the decline in observed diaper dermatitis among infants. Where adult incontinence-related skin problems are concerned, it is very important to apply a holistic perspective to understand the influences due to the individual's incontinence level and skin condition, as well as the hygiene and skin care measures provided. Individuals with frail, sensitive skin or with skin diseases may preferably have to use high-quality products, equipped with superabsorbent polymers and water vapor-permeable back sheets, to minimize the risk of skin complications.

  15. Energy deposition and radiological studies for the LBNF Hadron Absorber

    CERN Document Server

    Rakhno, I L; Tropin, I S; Eidelman, Y I

    2015-01-01

    Results of detailed Monte Carlo energy deposition and radiological studies performed for the LBNF hadron absorber 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. Both normal operation and accidental conditions were studied. Results of detailed thermal calculations with the ANSYS code helped to select the most viable design options.

  16. Development of the FracTherm absorber - simulations and experiments; Entwicklung des FracTherm-Absorbers - Simulationen und Experimente

    Energy Technology Data Exchange (ETDEWEB)

    Hermann, M. [Fraunhofer Inst. fuer Solare Energiesysteme, Freiburg (Germany)

    2005-07-01

    The energy efficiency of a solar absorber is strongly influenced by the flow of the heat transfer fluid. In order to obtain a high thermal efficiency (expressed by a high collector efficiency factor F'), the volume flow distribution should be uniform all over the absorber. Moreover, the pressure drop should be low in order to reduce the primary energy which is needed to drive the pump. Conventional absorber designs often show disadvantages (e.g. high pressure drop for serial connection, non-uniform flow distribution for parallel connection). This paper describes an alternative, ''bionic'' approach with a multiple branched, ''fractal'' channel design for solar absorbers. The aim of a current research work, which is sponsored by the Scholarship Programme of the German Federal Environmental Foundation (DBU), is to compare these structures with conventional ones concerning the pressure drop and the thermal efficiency. In order to achieve a fractal channel design on a given area, an algorithm (patent pending) and a simulation programme called FracTherm were developed. FracTherm allows to calculate the volume flow distribution, the pressure drop as well as the distribution of the collector efficiency factor F' and the fluid temperature. The simulations show that rather high F' values (about 0.97) can be expected (water; about 50 l/(m{sup 2}h)). Flow experiments with ink and thermography with an absorber model also revealed a uniform flow distribution and indicate a high thermal efficiency. Three aluminium test absorbers (590 mm x 1000 mm) were built by the Pechiney Rhenalu Chambery Company using the rollbond process. (orig.)

  17. Numerical modeling of incline plate LiBr absorber

    Science.gov (United States)

    Karami, Shahram; Farhanieh, Bijan

    2011-03-01

    Among major components of LiBr-H2O absorption chillers is the absorber, which has a direct effect on the chillier size and whose characteristics have significant effects on the overall efficiency of absorption machines. In this article, heat and mass transfer process in absorption of refrigerant vapor into a lithium bromide solution of water-cooled incline plate absorber in the Reynolds number range of 5 absorption. An analysis for linear distribution of wall temperature condition carries out to investigate the reliability of the present numerical method through comparing with previous investigation. The effect of plate angle on heat and mass transfer parameters is investigated and the results show that absorption mass flux and heat and mass transfer coefficient increase as the angle of the plate increase. The main parameters of absorber design, namely Nusselt and Sherwood numbers, are correlated as a function of Reynolds Number and the plate angle.

  18. A principle of similarity for nonlinear vibration absorbers

    Science.gov (United States)

    Habib, G.; Kerschen, G.

    2016-10-01

    This paper develops a principle of similarity for the design of a nonlinear absorber, the nonlinear tuned vibration absorber (NLTVA), attached to a nonlinear primary system. Specifically, for effective vibration mitigation, we show that the NLTVA should feature a nonlinearity possessing the same mathematical form as that of the primary system. A compact analytical formula for the nonlinear coefficient of the absorber is then derived. The formula, valid for any polynomial nonlinearity in the primary system, is found to depend only on the mass ratio and on the nonlinear coefficient of the primary system. When the primary system comprises several polynomial nonlinearities, we demonstrate that the NLTVA obeys a principle of additivity, i.e., each nonlinear coefficient can be calculated independently of the other nonlinear coefficients using the proposed formula.

  19. Performance of a Multifunctional Space Evaporator-Absorber-Radiator (SEAR)

    Science.gov (United States)

    Izenson, Michael G.; Chen, Weibo; Phillips, Scott; Chepko, Ariane; Bue, Grant; Quinn, Gregory

    2014-01-01

    The Space Evaporator-Absorber-Radiator (SEAR) is a nonventing thermal control subsystem that combines a Space Water Membrane Evaporator (SWME) with a Lithium Chloride Absorber Radiator (LCAR). The LCAR is a heat pump radiator that absorbs water vapor produced in the SWME. Because of the very low water vapor pressure at equilibrium with lithium chloride solution, the LCAR can absorb water vapor at a temperature considerably higher than the SWME, enabling heat rejection sufficient for most EVA activities by thermal radiation from a relatively small area radiator. Prior SEAR prototypes used a flexible LCAR that was designed to be installed on the outer surface of a portable life support system (PLSS) backpack. This paper describes a SEAR subsystem that incorporates a very compact LCAR. The compact, multifunctional LCAR is built in the form of thin panels that can also serve as the PLSS structural shell. We designed and assembled a 2 ft² prototype LCAR based on this design and measured its performance in thermal vacuum tests when supplied with water vapor by a SWME. These tests validated our models for SEAR performance and showed that there is enough area available on the PLSS backpack shell to enable rejection of metabolic heat from the LCAR. We used results of these tests to assess future performance potential and suggest approaches for integrating the SEAR system with future space suits.

  20. Sensors of absorbed dose of ionizing radiation based on mosfet

    Directory of Open Access Journals (Sweden)

    Perevertaylo V. L.

    2010-10-01

    Full Text Available The requirements to technology and design of p-channel and n-channel MOS transistors with a thick oxide layer designed for use in the capacity of integral dosimeters of absorbed dose of ionizing radiation are defined. The technology of radiation-sensitive MOS transistors with a thick oxide in the p-channel and n-channel version is created.

  1. Frequency-tunable terahertz absorbers based on graphene metasurface

    Science.gov (United States)

    Chen, Ming; Sun, Wei; Cai, Jianjin; Chang, Linzi; Xiao, Xiaofei

    2017-01-01

    We present efficient designs of graphene-based thin absorbers, which are capable of near-unity absorption of the incident electromagnetic waves in the terahertz regime. Primarily, a single-frequency absorber is proposed. Subsequently, by simply stacking the double layer graphene metasurface with various geometric dimensions, the dual-frequency absorption and broadband absorption are realized respectively. Results demonstrate that the absorptivity of the single-frequency absorber reaches 99.51% at 2.71 THz when the Fermi energy is fixed at 0.9 eV. The dual-frequency absorber can simultaneously work at two frequencies with its absorptivity being 98.94% for 1.99 THz and 99.1% for 2.69 THz. The bandwidth of absorption rate above 90% expands three times when compared with the former single-frequency absorber. Additionally, it possesses the polarization-insensitive and large angle tolerance properties. More importantly, the absorption frequency can be dynamically controlled by adjusting Fermi energy levels without varying the nanostructure, which exhibits tremendous application values in many fields.

  2. Advanced UV Absorbers for the Protection of Human Skin.

    Science.gov (United States)

    Hüglin, Dietmar

    The increasing awareness of the damaging effects of UV radiation to human skin triggered the market introduction of new cosmetic UV absorbers. This article summarizes the outcome of a multi-year research program, in which the author contributed to the development of different new UV filters. First of all, the molecular design and the basic properties of bis-ethylhexyloxyphenol methoxyphenyl triazine (BEMT) will be presented. This oil-soluble filter, which today is widely used in both beach products and skin care products, exhibits inherent photostability and strong broad-spectrum UV-A+B absorbance. Based on the concept of micronized organic UV absorbers, the UV-B filter tris biphenyl triazine (TBPT) will be introduced. At present TBPT exhibits the highest efficacy of all cosmetic UV absorbers in the market (measured by area under the UV spectrum). Finally, the concept of liposomogenic UV absorbers will be featured. This approach was developed to create water-resistant UV filters, as liposomogenic structures are thought to integrate into the lipids of the horny layer. Due to prohibitively high costs, this technology did not result in a commercial product so far.

  3. Numerical simulations of quasar absorbers

    CERN Document Server

    Theuns, T

    2005-01-01

    The physical state of the intergalactic medium can be probed in great detail with the intervening absorption systems seen in quasar spectra. The properties of the Hydrogen absorbers depend on many cosmological parameters, such as the matter-power spectrum, reionisation history, ionising background and the nature of the dark matter. The spectra also contain metal lines, which can be used to constrain the star formation history and the feedback processes acting in large and small galaxies. Simulations have been instrumental in investigating to what extent these parameters can be unambiguously constrained with current and future data. This paper is meant as an introduction to this subject, and reviews techniques and methods for simulating the intergalactic medium.

  4. Novel quad-band terahertz metamaterial absorber based on single pattern U-shaped resonator

    Science.gov (United States)

    Wang, Ben-Xin; Wang, Gui-Zhen

    2017-03-01

    A novel quad-band terahertz metamaterial absorber using four different modes of single pattern resonator is demonstrated. Four obvious frequencies with near-perfect absorption are realized. Near-field distributions of the four modes are provided to reveal the physical picture of the multiple-band absorption. Unlike most previous quad-band absorbers that typically require four or more patterns, the designed absorber has only one resonant structure, which is simpler than previous works. The presented quad-band absorber has potential applications in biological sensing, medical imaging, and material detection.

  5. Ultrathin low-frequency sound absorbing panels based on coplanar spiral tubes or coplanar Helmholtz resonators

    Science.gov (United States)

    Cai, Xiaobing; Guo, Qiuquan; Hu, Gengkai; Yang, Jun

    2014-09-01

    Performance of classic sound absorbing materials strictly depends on their thickness, with a minimum of one-quarter wavelength to reach full sound absorption. In this paper, we report ultrathin sound absorbing panels that completely absorb sound energy with a thickness around one percent of wavelength. The strategy is to bend and coil up quarter-wavelength sound damping tubes into 2D coplanar ones, and embed them into a matrix to form sound absorbing panel. Samples have been designed and fabricated by 3D printing. Efficacies of sound absorption by these panels were validated through good agreement between theoretical analysis and experimental measurements.

  6. Warm Absorbers in Active Galactic Nuclei

    CERN Document Server

    Komossa, S

    2000-01-01

    We first provide a review of the properties of warm absorbers concentrating on what we have learned from ROSAT and ASCA. This includes dusty and dust-free warm absorbers, non-X-ray emission and absorption features of warm absorbers, and the possible warm absorber interpretation of the peculiar 1.1 keV features. We then discuss facets of warm absorbers by a more detailed investigation of individual objects: In a first part, we discuss several candidates for dusty warm absorbers. In a second part, we review and extend our earlier study of a possible relation between warm absorber and CLR in NGC 4051, and confirm that both components are of different origin (the observed coronal lines are underpredicted by the models, the warm absorber is too highly ionized). We then suggest that a potential overprediction of these lines in more lowly ionized absorbers can be avoided if these warm absorbers are dusty. In a third part, we present first results of an analysis of a deep ROSAT PSPC observation of the quasar MR2251-1...

  7. Theoretical and thermal characterization of a wideband perfect absorber for application in solar cells

    Science.gov (United States)

    Rufangura, Patrick; Sabah, Cumali

    2016-12-01

    This paper suggests a metamaterial (MTM) absorber structure to be used for efficiency improved solar cell. The proposed MTM absorber consists of the topmost three concentric circular ring resonators, and a ground metal plane sandwiched to the top layer with a dielectric spacer. Numerical simulation and theoretical (interference theory) studies on the proposed design show a wideband with near-perfect (>99%) absorption response in the visible frequency region of the solar spectrum. Thermal characterization of the suggested design is also conducted in order to investigate its absorption capability at different temperatures. The proposed MTM absorber design is believed to be an outstanding candidate toward high-efficiency solar photovoltaic cell.

  8. Multiobjective Topology Optimization of Energy Absorbing Materials

    Science.gov (United States)

    2015-08-01

    125–143 DOI 10.1007/s00158-014-1117-8 RESEARCH PAPER Multiobjective topology optimization of energy absorbing materials Raymond A. Wildman · George A...recent developments. J Multiscale Model 3(4):1–42 Qiao P, Yang M, Bobaru F (2008) Impact mechanics and high-energy absorbing materials: review . J Aerosp...ARL-RP-0533 ● AUG 2015 US Army Research Laboratory Multiobjective Topology Optimization of Energy Absorbing Materials by

  9. Absorbent product and articles made therefrom

    Science.gov (United States)

    Dawn, F. S.; Correale, J. V. (Inventor)

    1982-01-01

    A multilayer absorbent product for use in contact with the skin to absorb fluids is described. The product has a water pervious facing layer for contacting the skin, and a first fibrous wicking layer overlaying the water pervious layer. A first container section is defined by inner and outer layers of a water pervious wicking material in between a first absorbent mass and a second container section defined by inner and outer layers of a water pervious wicking material between what is disposed a second absorbent mass, and a liquid impermeable/gas permeable layer overlaying the second fibrous wicking layer.

  10. 宽带超薄完美吸波体设计及在圆极化倾斜波束天线雷达散射截面缩减中的应用研究*%Design of ultra-thin broadband metamaterial absorber and its application for RCS reduction of circular polarization tilted beam antenna∗

    Institute of Scientific and Technical Information of China (English)

    李思佳; 曹祥玉; 高军; 刘涛; 杨欢欢; 李文强

    2013-01-01

      为了缩减天线带内雷达散射截面(radar cross section, RCS),在双频带完美吸波材料的基础上,通过缩小两吸波率峰值之间的距离,设计出了一种频带较宽的超薄完美吸波体.该吸波体由两层金属及其中间的有耗介质组成,底面金属不刻蚀,顶面由方形贴片和绕其四周的开口方环组成,该结构具有低频点LC谐振和高频点偶极子谐振的特征.仿真和实验结果表明:该吸波体具有极化不敏感和宽入射角的特征,其在厚度小于0.01λ的条件下,具有8.2%的半波功率相对带宽,最大吸波率的峰值为91.6%和96.5%.将吸波体用于圆极化的倾斜波束(tilted beam, TB)天线,仿真和测试结果表明:该天线在保持增益不变的条件下,不仅轴比得到改善,有效带宽得到拓展,且在5.5—6.5 GHz范围内TB天线的RCS缩减至少在3 dBsm以上,在谐振频点处最大缩减幅度分别为11 dBsm和8 dBsm;在两谐振点处鼻锥方向−36◦—+36◦范围内, TB天线的RCS缩减均有明显效果.%  In order to reduce the radar cross section (RCS) of antenna, a wideband-enhanced ultra-thin metamaterial absorber is designed by reducing the distance between the two absorption peaks due to the double resonances. The absorber is composed of two metallic layers separated by a lossy dielectric spacer. The top layer consists of a single-square loop with four splits on the four sides and a square metal patch in the center and the bottom one is of a solid metal. A dipole resonance and an LC resonance are caused by the structure of the metamaterial absorber. By fine adjusting geometry parameters of the structure, we can obtain a polarization-insensitive and wide-incident-angle ultra-thin absorber whose absorption values are 91.6%and 96.5%. On condition that thickness is less than 0.01λ the absorber has a full-width at half-maximum of 8.2%. The absorber is applied to the circularly polarized tilted beam antenna for reducing RCS

  11. Emitter and absorber assembly for multiple self-dual operation and directional transparency

    CERN Document Server

    Kalozoumis, P A; Kodaxis, G; Diakonos, F K; Schmelcher, P

    2016-01-01

    A recursive scheme for the design of scatterers acting simultaneously as emitters and absorbers, such as lasers and coherent perfect absorbers in optics, at multiple prescribed frequencies is proposed. The approach is based on the assembly of non-Hermitian emitter and absorber units into self-dual emitter-absorber trimers at different composition levels, exploiting the simple structure of the corresponding transfer matrices. In particular, lifting the restriction to parity-time-symmetric setups enables the realization of emitter and absorber action at distinct frequencies and provides flexibility in the choice of realistic parameters. We further show how the same assembled scatterers can be rearranged to produce unidirectional and bidirectional transparency at the selected frequencies. With the design procedure being generically applicable to wave scattering in single-channel settings, we demonstrate it with concrete examples of photonic multilayer setups.

  12. 21 CFR 872.6050 - Saliva absorber.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Saliva absorber. 872.6050 Section 872.6050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6050 Saliva absorber. (a) Identification. A...

  13. Comments on liquid hydrogen absorbers for MICE

    Energy Technology Data Exchange (ETDEWEB)

    Green, Michael A.

    2003-02-01

    This report describes the heat transfer problems associatedwith a liquid hydrogen absorber for the MICE experiment. This reportdescribes a technique for modeling heat transfer from the outside world,to the abosrber case and in its vacuum vessel, to the hydrogen and theninto helium gas at 14 K. Also presented are the equation for freeconvection cooling of the liquid hydrogen in the absorber.

  14. Multi-objective optimization of acoustic black hole vibration absorbers.

    Science.gov (United States)

    Shepherd, Micah R; Feurtado, Philip A; Conlon, Stephen C

    2016-09-01

    Structures with power law tapers exhibit the acoustic black hole (ABH) effect and can be used for vibration reduction. However, the design of ABHs for vibration reduction requires consideration of the underlying theory and its regions of validity. To address the competing nature of the best ABH design for vibration reduction and the underlying theoretical assumptions, a multi-objective approach is used to find the lowest frequency where both criteria are sufficiently met. The Pareto optimality curve is estimated for a range of ABH design parameters. The optimal set could then be used to implement an ABH vibration absorber.

  15. Stiffness control of magnetorheological gels for adaptive tunable vibration absorber

    Science.gov (United States)

    Kim, Hyun Kee; Kim, Hye Shin; Kim, Young-Keun

    2017-01-01

    In this study, a stiffness feedback control system for magnetorheological (MR) gel—a smart material of variable stiffness—is proposed, toward the design of a tunable vibration absorber that can adaptively tune to a time varying disturbance in real time. A PID controller was designed to track the required stiffness of the MR gel by controlling the magnitude of the target external magnetic field pervading the MR gel. This paper proposes a novel magnetic field generator that could produce a variable magnetic field with low energy consumption. The performance of the MR gel stiffness control was validated through experiments that showed the MR gel absorber system could be automatically tuned from 56 Hz to 67 Hz under a field of 100 mT to minimize the vibration of the primary system.

  16. PARAMETRIC MATCHING SELECTION OF MULTI-MEDIUM COUPLING SHOCK ABSORBER

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    To achieve the dual demand of resisting violent impact and attenuating vibration in vibration-impact-safety of protection for precision equipment such as MEMS packaging system, a theoretical mathematical model of multi-medium coupling shock absorber is presented. The coupling of quadratic damping, linear damping, Coulomb damping and nonlinear spring are considered in the model. The approximate theoretical calculating formulae are deduced by introducing transformation-tactics. The contrasts between the analytical results and numerical integration results are developed. The resisting impact characteristics of the model are also analyzed in progress. In the meantime,the optimum model of the parameters matching selection for design of the shock absorber is built.The example design is illustrated to confirm the validity of the modeling method and the theoretical solution.

  17. [Absorbed doses in dental radiology].

    Science.gov (United States)

    Bianchi, S D; Roccuzzo, M; Albrito, F; Ragona, R; Anglesio, S

    1996-01-01

    The growing use of dento-maxillo-facial radiographic examinations has been accompanied by the publication of a large number of studies on dosimetry. A thorough review of the literature is presented in this article. Most studies were carried out on tissue equivalent skull phantoms, while only a few were in vivo. The aim of the present study was to evaluate in vivo absorbed doses during Orthopantomography (OPT). Full Mouth Periapical Examination (FMPE) and Intraoral Tube Panoramic Radiography (ITPR). Measurements were made on 30 patients, reproducing clinical conditions, in 46 anatomical sites, with 24 intra- and 22 extra-oral thermoluminiscent dosimeters (TLDS). The highest doses were measured, in orthopantomography, at the right mandibular angle (1899 mu Gy) in FMPE on the right naso-labial fold (5640 mu Gy and in ITPR on the palatal surface of the left second upper molar (1936 mu Gy). Intraoral doses ranged from 21 mu Gy, in orthopantomography, to 4494 mu Gy in FMPE. Standard errors ranged from 142% in ITPR to 5% in orthopantomography. The highest rate of standard errors was found in FMPE and ITPR. The data collected in this trial are in agreement with others in major literature reports. Disagreements are probably due to different exam acquisition and data collections. Such differences, presented comparison in several sites, justify lower doses in FMPE and ITPR. Advantages and disadvantages of in vivo dosimetry of the maxillary region are discussed, the former being a close resemblance to clinical conditions of examination and the latter the impossibility of collecting values in depth of tissues. Finally, both ITPR and FMPE required lower doses than expected, and can be therefore reconsidered relative to their radiation risk.

  18. Removal of trichlorobenzene using 'oxygen-enriched' highly active absorbent.

    Science.gov (United States)

    Zhao, Yi; He, Peng; Zhang, Yu-Hai; Ma, Shuangchen

    2011-01-01

    Fly ash, industry lime and an additive, Ca(ClO2)2 (C) were used to prepare the 'oxygen-enriched' highly active absorbent (HAA). The influencing factors for removal of 1,2,4-trichlorobenzene (TCB) using this absorbent such as reaction temperature, simulating gas flow rate, oxygen content, etc. were studied in a self-designed reactor. The optimum experimental conditions of removing 1,2,4-TCB are that the content of an oxidizing additive in the absorbent is 3% (wt), simulating gas flow rate is 100 mL/min, reaction temperature is 250 degrees C, and the content of oxygen in simulating gas is 6%. The maximum removal efficiency is 81.71% in 10 mins. The absorption capacity of the absorbent is 0.000111 g/g. The reaction products were determined by gas chromatograph/mass spectrometer (GC/ MS), 2,6-Bis-[1,1-Dimethylethyl]-4-methyl-Phenol is considered to be the major intermediate product. The reaction route was revealed.

  19. Angle- and Polarization-Insensitive Metamaterial Absorber using Via Array

    Science.gov (United States)

    Lim, Daecheon; Lee, Dongju; Lim, Sungjoon

    2016-12-01

    In this paper, we propose an angle- and polarization-insensitive metamaterial absorber. We design a metamaterial unit cell that is based on a split ring cross resonator (SRCR). We observe that the absorption frequency and absorption ratio are insensitive to incident angles when a via array surrounds the SRR. We demonstrate the effect of the via array using full-wave simulations by comparing the absorptivity of the SRCR with and without the via array. Because of the symmetric geometry, we also realize polarization insensitivity. We build the proposed absorber on a printed-circuit-board with 30 × 30 unit cells, and we demonstrate its performance experimentally in free space. Under normal incidence, the fabricated absorber shows 99.6% absorptivity at 11.3 GHz for all polarization angles, while for oblique incidence, the fabricated absorber maintains an absorptivity higher than 90% for incident angles up to 70° and 60° for transverse magnetic (TM) and transverse electric (TE) modes, respectively.

  20. Angle- and Polarization-Insensitive Metamaterial Absorber using Via Array

    Science.gov (United States)

    Lim, Daecheon; Lee, Dongju; Lim, Sungjoon

    2016-01-01

    In this paper, we propose an angle- and polarization-insensitive metamaterial absorber. We design a metamaterial unit cell that is based on a split ring cross resonator (SRCR). We observe that the absorption frequency and absorption ratio are insensitive to incident angles when a via array surrounds the SRR. We demonstrate the effect of the via array using full-wave simulations by comparing the absorptivity of the SRCR with and without the via array. Because of the symmetric geometry, we also realize polarization insensitivity. We build the proposed absorber on a printed-circuit-board with 30 × 30 unit cells, and we demonstrate its performance experimentally in free space. Under normal incidence, the fabricated absorber shows 99.6% absorptivity at 11.3 GHz for all polarization angles, while for oblique incidence, the fabricated absorber maintains an absorptivity higher than 90% for incident angles up to 70° and 60° for transverse magnetic (TM) and transverse electric (TE) modes, respectively. PMID:28000770

  1. Absorber Coatings for Mid-Infrared Astrophysics

    Science.gov (United States)

    Baker, Dahlia Anne; Wollack, Edward; Rostem, Karwan

    2017-01-01

    Control over optical response is an important aspect of instrument design for astrophysical imaging. Here we consider a mid-infrared absorber coating proposed for use on HIRMES (High Resolution Mid-Infrared Spectrometer), a cryogenic spectrometer which will fly on the SOFIA (Stratospheric Observatory for Infrared Astronomy) aircraft. The aim of this effort is to develop an absorptive coating for the 20-200 microns spectral range based on a graphene loaded epoxy binder (Epotek 377H) and glass microsphere scatterers (3M K1). The coatings electromagnetic response was modeled using a Matlab script and the glass microspheres were characterized by the measured size distribution, the dielectric constant, and the filling fraction. Images of the microspheres taken by a microscope were used to determine the size distribution with an ImageJ particle analysis program. Representative test samples for optical evaluation were fabricated for characterization via infrared Fourier transform spectroscopy. The optical tests will determine the material’s absorptance and reflectance. These test results will be compared to the modeled response.

  2. Semiconductor nanowire optical antenna solar absorbers.

    Science.gov (United States)

    Cao, Linyou; Fan, Pengyu; Vasudev, Alok P; White, Justin S; Yu, Zongfu; Cai, Wenshan; Schuller, Jon A; Fan, Shanhui; Brongersma, Mark L

    2010-02-10

    Photovoltaic (PV) cells can serve as a virtually unlimited clean source of energy by converting sunlight into electrical power. Their importance is reflected in the tireless efforts that have been devoted to improving the electrical and structural properties of PV materials. More recently, photon management (PM) has emerged as a powerful additional means to boost energy conversion efficiencies. Here, we demonstrate an entirely new PM strategy that capitalizes on strong broad band optical antenna effects in one-dimensional semiconductor nanostructures to dramatically enhance absorption of sunlight. We show that the absorption of sunlight in Si nanowires (Si NWs) can be significantly enhanced over the bulk. The NW's optical properties also naturally give rise to an improved angular response. We propose that by patterning the silicon layer in a thin film PV cell into an array of NWs, one can boost the absorption for solar radiation by 25% while utilizing less than half of the semiconductor material (250% increase in the light absorption per unit volume of material). These results significantly advance our understanding of the way sunlight is absorbed by one-dimensional semiconductor nanostructures and provide a clear, intuitive guidance for the design of efficient NW solar cells. The presented approach is universal to any semiconductor and a wide range of nanostructures; as such, it provides a new PV platform technology.

  3. Practical absorption limits of MPP absorber

    Institute of Scientific and Technical Information of China (English)

    MAA Dah-You

    2006-01-01

    The construction and properties of microperforated panel (MPP) absorber are discussed. The absorption limit of the absorber had been shown that low values of the perforate constant k = d(f/10)1/2 and the orifice diameter d (in mm) are essential for MPP to have high absorption in wide frequency band. To find the exact limits, take 1 for k as a start, because both specific resistance and high absorption require k around one. And the orifice diameter d is chosen as 0.1 mm, so that the peak absorption coefficient (resonance absorption) is at 1000 Hz,and high sound frequency may be in the absorption region. Is it possible for a single layer of such an MPP to cover the whole absorption region required in practice? The half-absorption limit is not a good criterion, because low absorption comes in also in some cases. The 0.5 absorption coefficient limit is suggested for practical region, as a standard for comparison. Absorption curves were drawn for different load resistances, of absorption coefficients versus frequency.Ordinary MPP absorber absorbs in slightly over two octaves, and the new absorber with r = 1 (specific resistance equal to the characteristic impedance in air)is slightly better than these, 2.5 octaves. The new absorbers with r > 1, are much better than these, and some satisfies high absorption in broad frequency range. Realization of these will mean great progress of MPP absorbers.

  4. Absorbed dose by a CMOS in radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Borja H, C. G.; Valero L, C. Y.; Guzman G, K. A.; Banuelos F, A.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Paredes G, L. C., E-mail: candy_borja@hotmail.com [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2011-10-15

    Absorbed dose by a complementary metal oxide semiconductor (CMOS) circuit as part of a pacemaker, has been estimated using Monte Carlo calculations. For a cancer patient who is a pacemaker carrier, scattered radiation could damage pacemaker CMOS circuits affecting patient's health. Absorbed dose in CMOS circuit due to scattered photons is too small and therefore is not the cause of failures in pacemakers, but neutron calculations shown an absorbed dose that could cause damage in CMOS due to neutron-hydrogen interactions. (Author)

  5. Research on Simulation and Test of the Nonlinear Responses for the Hydraulic Shock Absorber

    Institute of Scientific and Technical Information of China (English)

    张建武; 刘延庆

    2003-01-01

    Basically on the multi-body system dynamics,the virtual prototype of the hydraulic shock absorber for the bench test is developed in the ADAMS environment.Dynamic behaviors of the absorber are studied by both computer simulation and real test.Numerical predictions of dynamic responses are produced by the established virtual prototype of the absorber and compared with experimental results.It has been shown from the comparison that the vibration behaviors of the prototype with hysteretic damping characteristics are considered to be more identical with the bench test results than those of the same prototype with piecewise linear damping properties are.The current virtual prototype of the shock absorber is correct and can be a developing terrace for the optimizing design of the absorber and matching capability of the whole car.

  6. Optical absorbers based on strong interference in ultra-thin films

    CERN Document Server

    Kats, Mikhail A

    2016-01-01

    Optical absorbers find uses in a wide array of applications across the electromagnetic spectrum, including photovoltaic and photochemical cells, photodetectors, optical filters, stealth technology, and thermal light sources. Recent efforts have sought to reduce the footprint of optical absorbers, conventionally based on graded structures or Fabry-Perot-type cavities, by using the emerging concepts of plasmonics, metamaterials, and metasurfaces. Unfortunately, these new absorber designs require patterning on subwavelength length scales, and are therefore impractical for many large-scale optical and optoelectronic devices. In this article, we summarize recent progress in the development of optical absorbers based on lossy films with thicknesses significantly smaller than the incident optical wavelength. These structures have a small footprint and require no nanoscale patterning. We outline the theoretical foundation of these absorbers based on "ultra-thin-film interference", including the concepts of loss-induc...

  7. Experimental Study of Heat Energy Absorber with Porous Medium for Thermoelectric Conversion System

    Directory of Open Access Journals (Sweden)

    Tzer-Ming Jeng

    2013-12-01

    Full Text Available The thermoelectric conversion system usually consists of the heat absorber, the thermoelectric generator (TEG and the heat sink, while the heat absorber collects the heat to increase the temperature on the hot surface of TEG and enhances the generating electricity. This study experimentally investigated the performance of the brass-beads packed-bed heat absorber for the thermoelectric conversion system. The packed-bed heat absorber is installed in a square channel with the various flow orientation systems and the small ratio of channel width to bead diameter. The flow orientation systems included the straight flow and jet flow systems. This study showed the local and average heat transfer characteristics for various parameters. The experimental results can be the base of designs for the novel porous heat absorber of the thermoelectric conversion system.

  8. Light-absorbing impurities in Arctic snow

    Directory of Open Access Journals (Sweden)

    S. J. Doherty

    2010-08-01

    Full Text Available Absorption of radiation by ice is extremely weak at visible and near-ultraviolet wavelengths, so small amounts of light-absorbing impurities in snow can dominate the absorption of solar radiation at these wavelengths, reducing the albedo relative to that of pure snow, contributing to the surface energy budget and leading to earlier snowmelt. In this study Arctic snow is surveyed for its content of light-absorbing impurities, expanding and updating the 1983–1984 survey of Clarke and Noone. Samples were collected in Alaska, Canada, Greenland, Svalbard, Norway, Russia, and the Arctic Ocean during 2005–2009, on tundra, glaciers, ice caps, sea ice, frozen lakes, and in boreal forests. Snow was collected mostly in spring, when the entire winter snowpack is accessible for sampling. Sampling was carried out in summer on the Greenland ice sheet and on the Arctic Ocean, of melting glacier snow and sea ice as well as cold snow. About 1200 snow samples have been analyzed for this study.

    The snow is melted and filtered; the filters are analyzed in a specially designed spectrophotometer system to infer the concentration of black carbon (BC, the fraction of absorption due to non-BC light-absorbing constituents and the absorption Ångstrom exponent of all particles. The reduction of snow albedo is primarily due to BC, but other impurities, principally brown (organic carbon, are typically responsible for ~40% of the visible and ultraviolet absorption. The meltwater from selected snow samples was saved for chemical analysis to identify sources of the impurities. Median BC amounts in surface snow are as follows (nanograms of carbon per gram of snow: Greenland 3, Arctic Ocean snow 7, melting sea ice 8, Arctic Canada 8, Subarctic Canada 14, Svalbard 13, Northern Norway 21, Western Arctic Russia 26, Northeastern Siberia 17. Concentrations are more variable in the European Arctic than in Arctic Canada or the Arctic Ocean, probably because of the proximity

  9. Synchronous and non-synchronous responses of systems with multiple identical nonlinear vibration absorbers

    Science.gov (United States)

    Issa, Jimmy S.; Shaw, Steven W.

    2015-07-01

    In this work we investigate the nonlinear dynamic response of systems composed of a primary inertia to which multiple identical vibration absorbers are attached. This problem is motivated by observations of systems of centrifugal pendulum vibration absorbers that are designed to reduce engine order torsional vibrations in rotating systems, but the results are relevant to translational systems as well. In these systems the total absorber mass is split into multiple equal masses for purposes of distribution and/or balance, and it is generally expected that the absorbers will act in unison, corresponding to a synchronous response. In order to capture nonlinear effects of the responses of the absorbers, specifically, their amplitude-dependent frequency, we consider them to possess nonlinear stiffness. The equations of motion for the system are derived and it is shown how one can uncouple the equations for the absorbers from that for the primary inertia, resulting in a system of identical resonators that are globally coupled. These symmetric equations are scaled for weak nonlinear effects, near resonant forcing, and small damping. The method of averaging is applied, from which steady-state responses and their stability are investigated. The response of systems with two, three, and four absorbers are considered in detail, demonstrating a rich variety of bifurcations of the synchronous response, resulting in responses with various levels of symmetry in which sub-groups of absorbers are mutually synchronous. It is also shown that undamped models with more than two absorbers possess a degenerate response, which is made robust by the addition of damping to the model. Design guidelines are proposed based on the nature of the system response, with the aim of minimizing the acceleration of the primary system. It is shown that the desired absorber parameters are selected so that the system achieves a stable synchronous response which does not undergo jumps via saddle

  10. A Method for Reducing Noise Radiated from Structures with Vibration Absorbers by Using an Accelerated Neural Network

    Institute of Scientific and Technical Information of China (English)

    李连进; 葛为民

    2004-01-01

    A method for reducing noise radiated from structures by vibration absorbers is presented. Since usual design method for the absorbers is invalid for noise reduction, the peaks of noise power in the frequency domain as cost functions are applied. Hence, the equations for obtaining optimal parameters of the absorbers become nonlinear expressions. To have the parameters, an accelerated neural network procedure has been presented. Numerical calculations have been carried out for a plate-type cantilever beam with a large width, and experimental tests have been also performed for the same beam. It is clarified that the present method is valid for reducing noise radiated from structures. As for the usual design method for the absorbers, model analysis has been given, so the number of absorbers should be the same as that of the considered modes. While the nonlinear problem can be dealt with by the present method, there is no restriction on the number of absorbers or the model number.

  11. Space Compatible Radar Absorbing Materials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase 1 project shall investigate novel radar absorbing materials (RAM) for use in space or simulated space environments. These materials are lightweight...

  12. High-Capacity Spacesuit Evaporator Absorber Radiator (SEAR)

    Science.gov (United States)

    Izenson, Michael G.; Chen, Weibo; Phillips, Scott; Chepko, Ariane; Bue, Grant; Quinn, Gregory

    2015-01-01

    Future human space exploration missions will require advanced life support technology that can operate across a wide range of applications and environments. Thermal control systems for space suits and spacecraft will need to meet critical requirements for water conservation and multifunctional operation. This paper describes a Space Evaporator Absorber Radiator (SEAR) that has been designed to meet performance requirements for future life support systems. A SEAR system comprises a lithium chloride absorber radiator (LCAR) for heat rejection coupled with a space water membrane evaporator (SWME) for heat acquisition. SEAR systems provide heat pumping to minimize radiator size, thermal storage to accommodate variable environmental conditions, and water absorption to minimize use of expendables. We have built and tested a flight-like, high-capacity LCAR, demonstrated its performance in thermal vacuum tests, and explored the feasibility of an ISS demonstration test of a SEAR system. The new LCAR design provides the same cooling capability as prior LCAR prototypes while enabling over 30% more heat absorbing capacity. Studies show that it should be feasible to demonstrate SEAR operation in flight by coupling with an existing EMU on the space station.

  13. Development of flat-plate solar thermal collectors equipped with aerogel sandwiched absorber

    Energy Technology Data Exchange (ETDEWEB)

    Goto, Yusuke; Izumi, Hiroaki; Aizawa, Mamoru [Dynax Corp. (Japan); Yugami, Hiroo [Graduate School of Engineering, Tohoku Univ. (Japan)

    2004-07-01

    It is important to utilize the solar energy efficiently. However, conventional solar thermal collectors have some drawbacks of high cost, heavy weight and low temperature output. These drawbacks prevent from spreading of the market of solar thermal collectors, especially in Japan. To find a solution to the problems, we propose an absorber / aerogel one-piece structure for high temperature solar thermal collectors. TiOxNy and silica aerogel were employed as a selectively solar-absorbing coating of absorber and as an optically transparent thermal insulator, respectively. Selectively solar-absorbing coatings must show lower reflectance and lower emittance. We have developed selectively solar-absorbing coatings of which optical property was {alpha} = 98.5, {epsilon} = 3 %. Wet coating of newly designed TiOxNy precursor enabled fabricating selectively solar-absorbing coatings, easily. Shrinkage of silica aerogel had to be minimized to produce an absorber / aerogel one-piece structure. Selectively solar-absorbing coatings and silica aerogel were prepared via sol-gel processing. (orig.)

  14. Semiconductor saturable absorbers for ultrafast THz signals

    DEFF Research Database (Denmark)

    Hoffmann, Matthias C.; Turchinovich, Dmitry

    We demonstrate saturable absorber behavior of n-type semiconductors in the THz frequency range using nonlinear THz spectroscopy. Further, we observe THz pulse shortening and increase of the group refractive index at high field strengths.......We demonstrate saturable absorber behavior of n-type semiconductors in the THz frequency range using nonlinear THz spectroscopy. Further, we observe THz pulse shortening and increase of the group refractive index at high field strengths....

  15. Taming electromagnetic metamaterials for isotropic perfect absorbers

    Directory of Open Access Journals (Sweden)

    Doan Tung Anh

    2015-07-01

    Full Text Available Conventional metamaterial absorbers, which consist of a dielectric spacer sandwiched between metamaterial resonators and a metallic ground plane, have been inherently anisotropic. In this paper, we present an alternative approach for isotropic perfect absorbers using symmetric metamaterial structures. We show that by systematically manipulating the electrically and magnetically induced losses, one can achieve a desired absorption without breaking the structural homogeneity. Finite integration simulations and standard retrieval method are performed to elaborate on our idea.

  16. Absorbing Boundary Conditions for Hyperbolic Systems

    Institute of Scientific and Technical Information of China (English)

    Matthias Ehrhardt

    2010-01-01

    This paper deals with absorbing boundary conditions for hyperbolic systems in one and two space dimensions. We prove the strict well-posedness of the resulting initial boundary value problem in 1D. Afterwards we establish the GKS-stability of the corresponding Lax-Wendroff-type finite difference scheme. Hereby, we have to extend the classical proofs, since the (discretized) absorbing boundary conditions do not fit the standard form of boundary conditions for hyperbolic systems.

  17. Absorption enhancement of a dual-band metamaterial absorber

    Science.gov (United States)

    Zhong, Min; Han, Gui Ming; Liu, Shui Jie; Xu, Bang Li; Wang, Jie; Huang, Hua Qing

    2017-02-01

    In this paper, we propose and fabricate a dual-band metamaterial absorber in 6-24 THz region. Electric field distribution reveal that the first absorption band is obtained from localized surface plasmon (LSP) modes which are excited both on inside and outside edges of each circular-patterned metal-dielectric stack, while the second absorption band is excited by LSP modes on outside edges of each stack. Measured results indicate that the absorption band width can be tuned by increasing the radius of circular-patterned layers or reducing the thickness of dielectric spacing layers. Moreover, the designed dual-band metamaterial absorber is independent on circular-patterned dielectric layer combinations.

  18. Multimodal tuned dynamic absorber for split Stirling linear cryocooler

    Science.gov (United States)

    Veprik, Alexander; Tuito, Avi

    2016-05-01

    Low size, weight, power and price split Stirling linear cryocooler usually comprises electro-dynamically driven compressor and pneumatically driven expander which are side-by-side fixedly mounted upon the common frame and interconnected by the configurable transfer line. Vibration export produced by such a cryocooler comprises of a pair of tonal forces, the frequency of which essentially equals fixed driving frequency. In vibration sensitive applications, this may result in excessive angular line of sight jitter and translational defocusing affecting the image quality. The authors present Multimodal Tuned Dynamic Absorber, having one translational and two tilting modes essentially tuned to the driving frequency. Dynamic analysis shows that the dynamic reactions (force and moment) produced by such a dynamic absorber are capable of simultaneous attenuation of translational and tilting components of cryocooler induced vibration. The authors reveal the preferable design, the method of fine tuning and outcomes of numerical simulation on attainable performance.

  19. Advances in micro-perforated panel absorbers

    Institute of Scientific and Technical Information of China (English)

    LIU Ke; TIAN Jing; JIAO Fenglei; L(U) Yadong

    2006-01-01

    Theoretical and experimental investigations on the performance of micro-perforated-panel absorbers are reviewed in this paper. By reviewing recent research work, this paper reveals a relationship between the maximum absorption coefficient and the limit of the absorption frequency bandwidth. It has been demonstrated that the absorption frequency bandwidth can be extended up to 3 or 4 octaves as the diameters of the micro-holes decrease. This has become possible with the development of the technologies for manufacturing micro-perforated panels,such as laser drilling, powder metallurgy, welded meshing and electro-etching to form micrometer order holes. In this paper, absorption characteristics of such absorbers in random fields and in high sound intensity are discussed both theoretically and experimentally. A new absorbing structure based on micro-perforated-panel absorbers demonstrate experimentally high sound absorption capability. This review shows that the micro-perforated-panel absorber has potentials to be one of ideal absorbing materials in the 21st century.

  20. Efficacy of an improved absorbent pad on incontinence-associated dermatitis in older women: cluster randomized controlled trial

    OpenAIRE

    Sugama Junko; Sanada Hiromi; Shigeta Yoshie; Nakagami Gojiro; Konya Chizuko

    2012-01-01

    Abstract Background Most older adults with urinary incontinence use absorbent pads. Because of exposure to moisture and chemical irritating substances in urine, the perineal skin region is always at risk for development of incontinence-associated dermatitis (IAD). The aim of this study was to examine the efficacy of an improved absorbent pad against IAD. Methods A cluster randomized controlled design was used to compare the efficacy of two absorbent pads. Female inpatients aged ≥65 years who ...

  1. A new laboratory-scale experimental facility for detailed aerothermal characterizations of volumetric absorbers

    Science.gov (United States)

    Gomez-Garcia, Fabrisio; Santiago, Sergio; Luque, Salvador; Romero, Manuel; Gonzalez-Aguilar, Jose

    2016-05-01

    This paper describes a new modular laboratory-scale experimental facility that was designed to conduct detailed aerothermal characterizations of volumetric absorbers for use in concentrating solar power plants. Absorbers are generally considered to be the element with the highest potential for efficiency gains in solar thermal energy systems. The configu-ration of volumetric absorbers enables concentrated solar radiation to penetrate deep into their solid structure, where it is progressively absorbed, prior to being transferred by convection to a working fluid flowing through the structure. Current design trends towards higher absorber outlet temperatures have led to the use of complex intricate geometries in novel ceramic and metallic elements to maximize the temperature deep inside the structure (thus reducing thermal emission losses at the front surface and increasing efficiency). Although numerical models simulate the conjugate heat transfer mechanisms along volumetric absorbers, they lack, in many cases, the accuracy that is required for precise aerothermal validations. The present work aims to aid this objective by the design, development, commissioning and operation of a new experimental facility which consists of a 7 kWe (1.2 kWth) high flux solar simulator, a radiation homogenizer, inlet and outlet collector modules and a working section that can accommodate volumetric absorbers up to 80 mm × 80 mm in cross-sectional area. Experimental measurements conducted in the facility include absorber solid temperature distributions along its depth, inlet and outlet air temperatures, air mass flow rate and pressure drop, incident radiative heat flux, and overall thermal efficiency. In addition, two windows allow for the direct visualization of the front and rear absorber surfaces, thus enabling full-coverage surface temperature measurements by thermal imaging cameras. This paper presents the results from the aerothermal characterization of a siliconized silicon

  2. Beam Pipe HOM Absorber for 750 MHz RF Cavity Systems

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Rolland; Neubauer, Michael

    2014-10-29

    This joint project of Muons, Inc., Cornell University and SLAC was supported by a Phase I and Phase II grant monitored by the SBIR Office of Science of the DOE. Beam line HOM absorbers are a critical part of future linear colliders. The use of lossy materials at cryogenic temperatures has been incorporated in several systems. The design in beam pipes requires cylinders of lossy material mechanically confined in such a way as to absorb the microwave energy from the higher-order modes and remove the heat generated in the lossy material. Furthermore, the potential for charge build-up on the surface of the lossy material requires the conductivity of the material to remain consistent from room temperature to cryogenic temperatures. In this program a mechanical design was developed that solved several design constraints: a) fitting into the existing Cornell load vacuum component, b) allowing the use of different material compositions, c) a thermal design that relied upon the compression of the lossy ceramic material without adding stress. Coating experiments were performed that indicated the design constraints needed to fully implement this approach for solving the charge build-up problem inherent in using lossy ceramics. In addition, the ACE3P program, used to calculate the performance of lossy cylinders in beam pipes in general, was supported by this project. Code development and documentation to allow for the more wide spread use of the program was a direct result of this project was well.

  3. Evaluation of the short- and long-term safety and therapy outcomes of the everolimus-eluting bioresorbable vascular scaffold system in patients with coronary artery stenosis: Rationale and design of the German–Austrian ABSORB RegIstRy (GABI-R)

    Energy Technology Data Exchange (ETDEWEB)

    Nef, Holger, E-mail: holger.nef@innere.med.uni-giessen.de [University of Giessen, Medizinische Klinik I, Department of Cardiology, Giessen (Germany); Wiebe, Jens [University of Giessen, Medizinische Klinik I, Department of Cardiology, Giessen (Germany); Achenbach, Stefan [University of Erlangen, Medizinische Klinik II, Department of Cardiology, Erlangen (Germany); Münzel, Thomas [Department of Medicine II, University Medical Center, Johannes Gutenberg University Mainz, Mainz (Germany); Naber, Christoph [Klinik für Kardiologie und Angiologie, Elisabeth-Krankenhaus, Essen (Germany); Richardt, Gert [Herzzentrum, Segeberger Kliniken GmbH, Bad Segeberg (Germany); Mehilli, Julinda [Department of Cardiology, Klinikum Großhadern, Ludwig- Maximilian Universität, Munich (Germany); Wöhrle, Jochen [Department of Internal Medicine II, University of Ulm, Ulm (Germany); Neumann, Till; Biermann, Janine [University of Essen, Department of Cardiology, Essen (Germany); Zahn, Ralf [Abteilung für Kardiologie, Herzzentrum Ludwigshafen, Ludwigshafen (Germany); Kastner, Johannes [Department of Cardiology, University of Vienna Medical School, Vienna (Austria); Schmermund, Axel [CCB, Cardioangiologisches Centrum Bethanien, Frankfurt (Germany); Pfannebecker, Thomas [Abbott Vascular Deutschland GmbH, Wetzlar (Germany); Schneider, Steffen; Limbourg, Tobias [Institut für Herzinfarktforschung, Ludwigshafen (Germany); Hamm, Christian W. [University of Giessen, Medizinische Klinik I, Department of Cardiology, Giessen (Germany); Kerckhoff Heart and Thorax Center, Department of Cardiology, Bad Nauheim (Germany)

    2016-01-15

    Background: Third-generation drug-eluting metal stents are the gold standard for treatment of coronary artery disease. The permanent metallic caging of the vessel, however, can result in limited vasomotion, chronic inflammation, and late expansive remodeling, conditions that can lead to late and very late stent thrombosis. The development of bioresorbable scaffolds (BRSs) promises advantages over metal stents due to complete biodegradation within 2–4 years. Theoretically, since vessel scaffolding is temporary and no permanent implant remains in the vessel, BRSs, as opposed to metal stents, once degraded would no longer be potential triggers for stent-related adverse events or side effects. Methods/design: The short- and long-term outcome after implantation of an everolimus-eluting, poly-L-lactic acid-based bioresorbable scaffold system (ABSORB, Abbott Vascular, Santa Clara, CA, USA) in the world-wide greatest all-comers cohort will be evaluated in the prospective, non-interventional, multicenter German–Austrian ABSORB RegIstRy (GABI-R). GABI-R will include over 5000 patients from about 100 study sites in Austria and Germany. Safety endpoints such as cardiac death, myocardial infarction, and clinically driven percutaneous or surgical target lesion and vessel revascularization will be evaluated during hospitalization and in the follow-up period (minimum of 5 years). Conclusion: Although two randomized controlled trials and several registries have documented safety and efficacy as well as non-inferiority of this everolimus-eluting ABSORB device compared with drug-eluting metal stents, the current knowledge regarding clinical application, treatment success, and long-term safety of using this BRS in daily routine is limited. Thus, the goal of GABI-R is to address this lack of information. - Highlights: • The GABI-R addresses a lack of data about bioresorbable scaffolds in daily practice. • 5000 patients with minimal in- and exclusion criteria at 100 sites will

  4. A Novel Absorbing Boundary Condition for the Frequency-DependentFinite-Difference Time-Domain Method

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A new absorbing boundary condition (ABC) for frequency-dependent finite-difference time-domain algorithm for the arbitrary dispersive media is presented. The concepts of the digital systems are introduced to the (FD)2TD method. On the basis of digital filter designing and vector algebra, the absorbing boundary condition under arbitrary angle of incidence are derived. The transient electromagnetic problems in two-dimensions and three-dimensions are calculated and the validity of the ABC is verified.

  5. Study on the shock absorbing technique of high speed railway bridges

    Institute of Scientific and Technical Information of China (English)

    Li Chenggen; Gao Ri

    2011-01-01

    Based on the idea of "bearing function separation", a structural member called shock absorber that makes use of its plastic deformation is presented for reducing the seismic response of the bridge. The design criterion for matching material stress, strain and earthquake fortification aim, is also given. The analysis results show that the high speed railway box girder with the absorber in this paper has great reduction effect in seismic response of the bridge piers.

  6. Warm Absorber Diagnostics of AGN Dynamics

    Science.gov (United States)

    Kallman, Timothy

    Warm absorbers and related phenomena are observable manifestations of outflows or winds from active galactic nuclei (AGN) that have great potential value. Understanding AGN outflows is important for explaining the mass budgets of the central accreting black hole, and also for understanding feedback and the apparent co-evolution of black holes and their host galaxies. In the X-ray band warm absorbers are observed as photoelectric absorption and resonance line scattering features in the 0.5-10 keV energy band; the UV band also shows resonance line absorption. Warm absorbers are common in low luminosity AGN and they have been extensively studied observationally. They may play an important role in AGN feedback, regulating the net accretion onto the black hole and providing mechanical energy to the surroundings. However, fundamental properties of the warm absorbers are not known: What is the mechanism which drives the outflow?; what is the gas density in the flow and the geometrical distribution of the outflow?; what is the explanation for the apparent relation between warm absorbers and the surprising quasi-relativistic 'ultrafast outflows' (UFOs)? We propose a focused set of model calculations that are aimed at synthesizing observable properties of warm absorber flows and associated quantities. These will be used to explore various scenarios for warm absorber dynamics in order to answer the questions in the previous paragraph. The guiding principle will be to examine as wide a range as possible of warm absorber driving mechanisms, geometry and other properties, but with as careful consideration as possible to physical consistency. We will build on our previous work, which was a systematic campaign for testing important class of scenarios for driving the outflows. We have developed a set of tools that are unique and well suited for dynamical calculations including radiation in this context. We also have state-of-the-art tools for generating synthetic spectra, which are

  7. Detecting and interpreting statistical lensing by absorbers

    CERN Document Server

    Ménard, B

    2004-01-01

    We propose a method for detecting gravitational magnification of distant sources, like quasars, due to absorber systems detected in their spectra. We first motivate the use of metal absorption lines rather than Lyman-alpha lines, then we show how to relate the observed moments of the source magnitude distribution to the mass distribution of absorbers. In order to illustrate the feasibility of the method, we use a simple model to estimate the amplitude of the effect expected for MgII absorption lines, and show that their lensing signal might already be detectable in large surveys like the SDSS. Our model suggests that quasars behind strong MgII absorbers are in average brightened by -0.05 to -0.2 magnitude due to magnification. One must therefore revisit the claim that, in magnitude limited surveys, quasars with strong absorbers tend to be missed due to extinction effects. In addition to constraining the mass of absorber systems, applying our method will allow for the quantification of this bias.

  8. Ultrathin flexible dual band terahertz absorber

    Science.gov (United States)

    Shan, Yan; Chen, Lin; Shi, Cheng; Cheng, Zhaoxiang; Zang, Xiaofei; Xu, Boqing; Zhu, Yiming

    2015-09-01

    We propose an ultrathin and flexible dual band absorber operated at terahertz frequencies based on metamaterial. The metamaterial structure consists of periodical split ring resonators with two asymmetric gaps and a metallic ground plane, separated by a thin-flexible dielectric spacer. Particularly, the dielectric spacer is a free-standing polyimide film with thickness of 25 μm, resulting in highly flexible for our absorber and making it promising for non-planar applications such as micro-bolometers and stealth aircraft. Experimental results show that the absorber has two resonant absorption frequencies (0.41 THz and 0.75 THz) with absorption rates 92.2% and 97.4%, respectively. The resonances at the absorption frequencies come from normal dipole resonance and high-order dipole resonance which is inaccessible in the symmetrical structure. Multiple reflection interference theory is used to analyze the mechanism of the absorber and the results are in good agreement with simulated and experimental results. Furthermore, the absorption properties are studied under various spacer thicknesses. This kind of metamaterial absorber is insensitive to polarization, has high absorption rates (over 90%) with wide incident angles range from 0° to 45° and the absorption rates are also above 90% when wrapping it to a curved surface.

  9. Oxygen absorbers in food preservation: a review.

    Science.gov (United States)

    Cichello, Simon Angelo

    2015-04-01

    The preservation of packaged food against oxidative degradation is essential to establish and improve food shelf life, customer acceptability, and increase food security. Oxygen absorbers have an important role in the removal of dissolved oxygen, preserving the colour, texture and aroma of different food products, and importantly inhibition of food spoilage microbes. Active packaging technology in food preservation has improved over decades mostly due to the sealing of foods in oxygen impermeable package material and the quality of oxygen absorber. Ferrous iron oxides are the most reliable and commonly used oxygen absorbers within the food industry. Oxygen absorbers have been transformed from sachets of dried iron-powder to simple self-adhesive patches to accommodate any custom size, capacity and application. Oxygen concentration can be effectively lowered to 100 ppm, with applications spanning a wide range of food products and beverages across the world (i.e. bread, meat, fish, fruit, and cheese). Newer molecules that preserve packaged food materials from all forms of degradation are being developed, however oxygen absorbers remain a staple product for the preservation of food and pharmaceutical products to reduce food wastage in developed nations and increased food security in the developing & third world.

  10. Distributed Absorber for Noise and Vibration Control

    Directory of Open Access Journals (Sweden)

    Michel Azoulay

    2011-01-01

    Full Text Available An approach to a wide-band frequency passive vibration attenuation is introduced in this paper. This aims to suppress noise and vibration of extended multimode objects like plates, panels and shells. The absorber is arranged in the form of a single-layer assembly of small inertial bodies (balls being distributed and moulded within the light visco-elastic media (e.g. silicone resin. The absorber as a whole is embedded into object face covering the critical patches of the system surface. For the purpose of characterization, the authors introduced the complex frequency response function relating the volume velocity produced by the vibrating object surface (response stimulated by a point-wise force (stimulus applied to a particular point. The simulation and optimization of the main frequency characteristics has been performed using a full scale 3-dimensional Finite Element model. These revealed some new dynamic features of absorber's structures, which can contribute to vibration attenuation. A full-scale physical experimentation with synthesised absorber's structures confirmed the main results of simulation and has shown significant noise reduction over a staggering 0–20 kHz frequency band. This was achieved with a negligible weight and volume penalty due to the addition of the absorber. The results can find multiple applications in noise and vibration control of different structures. Some examples of such applications are presented.

  11. A metamaterial absorber with direction-selective and polarisation-insensitive properties

    Institute of Scientific and Technical Information of China (English)

    Gu Chao; Qu Shao-Bo; Pei Zhi-Bin; Xu Zhuo

    2011-01-01

    This paper reports the design of a metamaterial absorber with direction-selective and polarisation-insensitive property. Both theoretical and simulated results reveal that the absorber has a distinct absorption point with direction selectivity at 7.48 GHz, which is related to the resonance of the metamaterial and is not influenced by the polarisation. The retrieved impedance indicates that the impedance of the absorber can be tuned to approximatively match the impedance of the free space on one side and not to match the impedance of the free space on the other side. This design can result in the minimal reflectance, the minimal transmission and the highest absorbance at the absorption frequency. The distribution of the power loss indicates that the absorber is an excellent electromagnetic wave collector: the wave is first trapped and reinforced in certain specific locations, and then mostly consumed. The distribution of the surface current is consistent with the design, the retrieved impedance and the distribution of the power loss. This absorber may have applications in many scientific and technological areas.

  12. Energy scavenging strain absorber: application to kinetic dielectric elastomer generator

    Science.gov (United States)

    Jean-Mistral, C.; Beaune, M.; Vu-Cong, T.; Sylvestre, A.

    2014-03-01

    Dielectric elastomer generators (DEGs) are light, compliant, silent energy scavengers. They can easily be incorporated into clothing where they could scavenge energy from the human kinetic movements for biomedical applications. Nevertheless, scavengers based on dielectric elastomers are soft electrostatic generators requiring a high voltage source to polarize them and high external strain, which constitutes the two major disadvantages of these transducers. We propose here a complete structure made up of a strain absorber, a DEG and a simple electronic power circuit. This new structure looks like a patch, can be attached on human's wear and located on the chest, knee, elbow… Our original strain absorber, inspired from a sailing boat winch, is able to heighten the external available strain with a minimal factor of 2. The DEG is made of silicone Danfoss Polypower and it has a total area of 6cm per 2.5cm sustaining a maximal strain of 50% at 1Hz. A complete electromechanical analytical model was developed for the DEG associated to this strain absorber. With a poling voltage of 800V, a scavenged energy of 0.57mJ per cycle is achieved with our complete structure. The performance of the DEG can further be improved by enhancing the imposed strain, by designing a stack structure, by using a dielectric elastomer with high dielectric permittivity.

  13. Graphene metamaterial for multiband and broadband terahertz absorber

    Science.gov (United States)

    Gao, Runmei; Xu, Zongcheng; Ding, Chunfeng; Wu, Liang; Yao, Jianquan

    2015-12-01

    In this paper, we present the efficient design of functional graphene thin film metamaterial on a metal-plane separated by a thick dielectric layer. Perfect absorption is characterized by the complete suppression of incident and reflected light and complete dissipation of incident energy. We investigate the properties of graphene metamaterials and demonstrate multiband absorbers that have five absorption bands, using silicon interlayers, in the 0-2.2 THz range. The absorption rate reached up to 99.9% at a frequency of 1.08 THz, and the quality factor was 6.98 for a 0.14 THz bandwidth. We present a novel theoretical interpretation based on standing wave field theory, which shows that coherent superposition of the incident and reflection rays produce stationary waves, and the field energy localized inside the thick spacers and dissipated through the metal-planes. Thus, light was effectively trapped in the metamaterial absorbers with negligible near-field interactions, causing high absorption. The theory developed here explains all features observed in multiband metamaterial absorbers and therefore provides a profound understanding of the underlying physical mechanisms.

  14. Wireless device for activation of an underground shock wave absorber

    Science.gov (United States)

    Chikhradze, M.; Akhvlediani, I.; Bochorishvili, N.; Mataradze, E.

    2011-10-01

    The paper describes the mechanism and design of the wireless device for activation of energy absorber for localization of blast energy in underground openings. The statistics shows that the greatest share of accidents with fatal results associate with explosions in coal mines due to aero-methane and/or air-coal media explosion. The other significant problem is terrorist or accidental explosions in underground structures. At present there are different protective systems to reduce the blast energy. One of the main parts of protective Systems is blast Identification and Registration Module. The works conducted at G. Tsulukidze Mining Institute of Georgia enabled to construct the wireless system of explosion detection and mitigation of shock waves. The system is based on the constant control on overpressure. The experimental research continues to fulfill the system based on both threats, on the constant control on overpressure and flame parameters, especially in underground structures and coal mines. Reaching the threshold value of any of those parameters, the system immediately starts the activation. The absorber contains a pyrotechnic device ensuring the discharge of dispersed water. The operational parameters of wireless device and activation mechanisms of pyrotechnic element of shock wave absorber are discussed in the paper.

  15. Absorbing material based on starch having improved absorbent properties and process for the preparation thereof

    NARCIS (Netherlands)

    Feil, H.; Soest, van J.J.G.; Schijndel, van R.J.G.

    1999-01-01

    A biodegradable, highly water-absorbing polymer based on starch or derivatives thereof is described, wherein the starch has not been chemically modified or only to a degree of substitution below 0.2, and has a water-absorbing power of at least 10 times its own weight, half of the water absorption be

  16. Non-Absorbable Gas Behavior in the Absorber/Evaporator of a Absorption Chiller

    Science.gov (United States)

    Suzuki, Hiroshi; Nagamoto, Wataru; Sugiyama, Takahide

    A two-dimensional numerical study on non-absorbable gas behavior in the absorber/evaporator of an absorption chiller has been performed. In the present study, the effect of the pitch-to-diameter ratio of a cylinder bundle in the absorber was highlighted. From the results, a sudden decrease of the overall heat transfer coefficient of the absorber was observed at a certain mean concentration of non-absorbable gas for each pitch-to-diameter ratio. Such a critical concentration was also found to decrease as the pitch-to- diameter ratio increased. The sudden decrease occurs due to the sudden disappearance of recirculating region, which is formed between the absorber and the evaporator, and where most of non-absorbable gas stays when it exists. As the pitch-to-diameter ratio increases, the recirculating region becomes weak because the velocity of the high velocity region supporting the recirculating flow decreases. Then, the critical mean concentration of non-absorbable gas is found to decrease as pitch-to-ratio increases.

  17. Interference theory of metamaterial perfect absorbers

    CERN Document Server

    Chen, Hou-Tong

    2011-01-01

    The impedance matching in metamaterial perfect absorbers has been believed to involve and rely on magnetic resonant response, with a direct evidence from the anti-parallel directions of surface currents in the metal structures. Here we present a different theoretical interpretation based on interferences, which shows that the two layers of metal structure in metamaterial absorbers are linked only by multiple reflections with negligible near-field interactions or magnetic resonances. This is further supported by the out-of-phase surface currents derived at the interfaces of resonator array and ground plane through multiple reflections and superpositions. The theory developed here explains all features observed in narrowband metamaterial absorbers and therefore provides a profound understanding of the underlying physics.

  18. Absorber Materials at Room and Cryogenic Temperatures

    Energy Technology Data Exchange (ETDEWEB)

    F. Marhauser, T.S. Elliott, A.T. Wu, E.P. Chojnacki, E. Savrun

    2011-09-01

    We recently reported on investigations of RF absorber materials at cryogenic temperatures conducted at Jefferson Laboratory (JLab). The work was initiated to find a replacement material for the 2 Kelvin low power waveguide Higher Order Mode (HOM) absorbers employed within the original cavity cryomodules of the Continuous Electron Beam Accelerator Facility (CEBAF). This effort eventually led to suitable candidates as reported in this paper. Furthermore, though constrained by small funds for labor and resources, we have analyzed a variety of lossy ceramic materials, several of which could be usable as HOM absorbers for both normal conducting and superconducting RF structures, e.g. as loads in cavity waveguides and beam tubes either at room or cryogenic temperatures and, depending on cooling measures, low to high operational power levels.

  19. Ferrite HOM Absorber for the RHIC ERL

    Energy Technology Data Exchange (ETDEWEB)

    Hahn,H.; Choi, E.M.; Hammons, L.

    2008-10-01

    A superconducting Energy Recovery Linac is under construction at Brookhaven National Laboratory to serve as test bed for RHIC upgrades. The damping of higher-order modes in the superconducting five-cell cavity for the Energy-Recovery linac at RHIC is performed exclusively by two ferrite absorbers. The ferrite properties have been measured in ferrite-loaded pill box cavities resulting in the permeability values given by a first-order Debye model for the tiled absorber structure and an equivalent permeability value for computer simulations with solid ring dampers. Measured and simulated results for the higher-order modes in the prototype copper cavity are discussed. First room-temperature measurements of the finished niobium cavity are presented which confirm the effective damping of higher-order modes in the ERL. by the ferrite absorbers.

  20. On the warm absorber in AGN outflow

    CERN Document Server

    Adhikari, T P; Sobolewska, M; Czerny, B

    2016-01-01

    Warm absorber (WA) is an ionised gas present in the line of sight to the AGN central engine. The effect of the absorber is imprinted in the absorption lines observed in X-ray spectra of AGN. In this work, we model the WA in Seyfert 1 galaxy Mrk 509 using its recently published shape of broad band spectral energy distribution (SED) as a continuum illuminating the absorber. Using the photoionization code {\\sc Titan}, recently we have shown that the absorption measure distribution (AMD) found for this object can be successfully modelled as a single slab of gas in total pressure (radiation+gas) equilibrium, contrary to the usual models of constant density multiple slabs. We discuss the transmitted spectrum that would be recorded by an observer after the radiation from the nucleus passes through the WA.

  1. Neutron absorbed dose in a pacemaker CMOS

    Energy Technology Data Exchange (ETDEWEB)

    Borja H, C. G.; Guzman G, K. A.; Valero L, C.; Banuelos F, A.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Paredes G, L., E-mail: fermineutron@yahoo.com [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2012-06-15

    The neutron spectrum and the absorbed dose in a Complementary Metal Oxide Semiconductor (CMOS), has been estimated using Monte Carlo methods. Eventually a person with a pacemaker becomes an oncology patient that must be treated in a linear accelerator. Pacemaker has integrated circuits as CMOS that are sensitive to intense and pulsed radiation fields. Above 7 MV therapeutic beam is contaminated with photoneutrons that could damage the CMOS. Here, the neutron spectrum and the absorbed dose in a CMOS cell was calculated, also the spectra were calculated in two point-like detectors in the room. Neutron spectrum in the CMOS cell shows a small peak between 0.1 to 1 MeV and a larger peak in the thermal region, joined by epithermal neutrons, same features were observed in the point-like detectors. The absorbed dose in the CMOS was 1.522 x 10{sup -17} Gy per neutron emitted by the source. (Author)

  2. Broadband plasmonic absorber for photonic integrated circuits

    CERN Document Server

    Xiong, Xiao; Ren, Xi-Feng; Guo, Guang-Can

    2013-01-01

    The loss of surface plasmon polaritons has long been considered as a fatal shortcoming in information transport. Here we propose a plasmonic absorber utilizing this "shortcoming" to absorb the stray light in photonic integrated circuits (PICs). Based on adiabatic mode evolution, its performance is insensitive to incident wavelength with bandwidth larger than 300nm, and robust against surrounding environment and temperature. Besides, the use of metal enables it to be very compact and beneficial to thermal dissipation. With this 40um-long absorber, the absorption efficiency can be over 99.8% at 1550nm, with both the reflectivity and transmittance of incident light reduced to less than 0.1%. Such device may find various applications in PICs, to eliminate the residual strong pump laser or stray light.

  3. A Thin C-Band Polarization and Incidence Angle-Insensitive Metamaterial Perfect Absorber

    Directory of Open Access Journals (Sweden)

    Humberto Fernández Álvarez

    2015-04-01

    Full Text Available A novel metamaterial absorber design able to operate in the C frequency band is presented, along with an analysis and a method to improve both its bandwidth and its angular stability. Simulation results for a FR4-based design are shown for comparison with existing designs. In addition, a simplified equivalent circuit is provided for a better understanding of the great angular stability and wide bandwidth exhibited by the proposed structure. Moreover, simulations, manufacturing and measurements of a thinner and more flexible metamaterial absorber, keeping the angular stability of the former one, while providing a wide bandwidth, are presented.

  4. 板型先进高温堆的可燃毒物装载优化%Optimal design of burnable poisons for the advanced plate-type high-temperature reactor

    Institute of Scientific and Technical Information of China (English)

    魏书华; 余笑寒; 邹杨; 戴叶; 朱贵凤

    2015-01-01

    板型先进高温堆(Advanced high-temperature reactor,AHTR)的设计概念是由美国橡树岭国家实验室提出并发展的,由于其初始剩余反应性较高,除控制棒外,还考虑采用可燃毒物来补偿剩余反应性.本文通过比较6种候选可燃毒物在燃耗后期的毒物残留特性,从中选取了B4C、Gd2O3、CdO和Er2O3四种球形可燃毒物,采用MCNP与Origen2的耦合程序对其尺寸和装载量进行优化计算.结果表明,可燃毒物Er2O3性能最佳,当每块燃料板装载176 9颗粒半径为740 μm的Er2O3时,剩余反应性大约从39 000 pcm降到4 400 pcm,燃耗深度只降低约3%.

  5. Vibration confinement and energy harvesting in flexible structures using collocated absorbers and piezoelectric devices

    Science.gov (United States)

    Ouled Chtiba, M.; Choura, S.; Nayfeh, A. H.; El-Borgi, S.

    2010-03-01

    We propose an optimal design for supplementing flexible structures with a set of absorbers and piezoelectric devices for vibration confinement and energy harvesting. We assume that the original structure is sensitive to vibrations and that the absorbers are the elements where the vibration energy is confined and then harvested by means of piezoelectric devices. The design of the additional mechanical and electrical components is formulated as a dynamic optimization problem in which the objective function is the total energy of the uncontrolled structure. The locations, masses, stiffnesses, and damping coefficients of these absorbers and capacitances, load resistances, and electromechanical coupling coefficients are optimized to minimize the total energy of the structure. We use the Galerkin procedure to discretize the equations of motion that describe the coupled dynamics of the flexible structure and the added absorbers and harvesting devices. We develop a numerical code that determines the unknown parameters of a pre-specified set of absorbers and harvesting components. We input a set of initial values for these parameters, and the code updates them while minimizing the total energy in the uncontrolled structure. To illustrate the proposed design, we consider a simply supported beam with harmonic external excitations. Here, we consider two possible configurations for each of the additional piezoelectric devices, either embedded between the structure and the absorbers or between the ground and absorbers. We present simulations of the harvested power and associated voltage for each pair of collocated absorber and piezoelectric device. The simulated responses of the beam show that its energy is confined and harvested simultaneously.

  6. Quantum walk with one variable absorbing boundary

    Science.gov (United States)

    Wang, Feiran; Zhang, Pei; Wang, Yunlong; Liu, Ruifeng; Gao, Hong; Li, Fuli

    2017-01-01

    Quantum walks constitute a promising ingredient in the research on quantum algorithms; consequently, exploring different types of quantum walks is of great significance for quantum information and quantum computation. In this study, we investigate the progress of quantum walks with a variable absorbing boundary and provide an analytical solution for the escape probability (the probability of a walker that is not absorbed by the boundary). We simulate the behavior of escape probability under different conditions, including the reflection coefficient, boundary location, and initial state. Moreover, it is also meaningful to extend our research to the situation of continuous-time and high-dimensional quantum walks.

  7. Spin Particle in an Absorbing Environment

    Science.gov (United States)

    Amooshahi, M.

    2015-10-01

    The quantum dynamics of a localized spin Particle interacting with an absorbing environment is investigated. The quantum Langevin-Schrödinger equation for spin is obtained. The susceptibility function of the environment is calculated in terms of the coupling function of the spin and the environment. it is shown that the susceptibility function satisfies the Kramers-Kronig relations. Spontaneous emission and the shift frequency of the spin is obtained in terms of the imaginary part of the susceptibility function in frequency domain. Some transition probabilities between the spin states are calculated when the absorbing environment is in the thermal state.

  8. Timing the warm absorber in NGC 4051

    Science.gov (United States)

    Silva, C. V.; Uttley, P.; Costantini, E.

    2016-12-01

    We investigated, using spectral-timing analysis, the characterization of highly ionized outflows in Seyfert galaxies, the so-called warm absorbers. Here, we present our results of the extensive 600 ks of XMM-Newton archival observations of the bright and highly variable Seyfert 1 galaxy NGC 4051 whose spectrum has revealed a complex multicomponent wind. Making use of both RGS and EPIC-pn data, we performed a detailed analysis through a time-dependent photoionization code in combination with spectral and Fourier spectral-timing techniques. The source light curves and the warm absorber parameters obtained from the data were used to simulate the response of the gas to variations in the ionizing flux of the central source. The resulting time variable spectra were employed to predict the effects of the warm absorber on the time lags and coherence of the energy dependent light curves. We have found that, in the absence of any other lag mechanisms, a warm absorber with the characteristics of the one observed in NGC 4051, is able to produce soft lags, up to 100 s, on timescales of hours. The time delay is associated with the response of the gas to changes in the ionizing source, either by photoionization or radiative recombination, which is dependent on its density. The range of radial distances that, under our assumptions, yield longer time delays are distances r 0.3-1.0 × 1016 cm, and hence gas densities n 0.4-3.0 × 107 cm-3. Since these ranges are comparable to the existing estimates of the location of the warm absorber in NGC 4051, we suggest that it is likely that the observed X-ray time lags may carry a signature of the warm absorber response time to changes in the ionizing continuum. Our results show that the warm absorber in NGC 4051 does not introduce lags on the short timescales associated with reverberation, but will likely modify the hard continuum lags seen on longer timescales, which in this source have been measured to be on the order of 50 s. Hence, these

  9. Durability of Polymeric Glazing and Absorber Materials

    Energy Technology Data Exchange (ETDEWEB)

    Jorgensen, G.; Terwilliger, K.; Bingham, C.; Lindquist, C.; Milbourne, M.

    2005-11-01

    The Solar Heating and Lighting Program has set the goal of reducing the cost of solar water heating systems by at least 50%. An attractive approach to such large cost reduction is to replace glass and metal parts with less-expensive, lighter-weight, more-integrated polymeric components. The key challenge with polymers is to maintain performance and assure requisite durability for extended lifetimes. We have begun evaluation of several new UV-screened polycarbonate sheet glazing constructions. This has involved interactions with several major polymer industry companies to obtain improved candidate samples. Proposed absorber materials were tested for UV resistance, and appear adequate for unglazed ICS absorbers.

  10. Absorbing metasurface created by diffractionless disordered arrays of nanoantennas

    Energy Technology Data Exchange (ETDEWEB)

    Chevalier, Paul [Minao, ONERA, The French Aerospace Lab, 91761 Palaiseau (France); Minao, Laboratoire de Photonique et Nanostructures (LPN), CNRS, Université Paris-Saclay, Route de Nozay, 91460 Marcoussis (France); Bouchon, Patrick, E-mail: patrick.bouchon@onera.fr; Jaeck, Julien; Lauwick, Diane; Kattnig, Alain [Minao, ONERA, The French Aerospace Lab, 91761 Palaiseau (France); Bardou, Nathalie; Pardo, Fabrice [Minao, Laboratoire de Photonique et Nanostructures (LPN), CNRS, Université Paris-Saclay, Route de Nozay, 91460 Marcoussis (France); Haïdar, Riad [Minao, ONERA, The French Aerospace Lab, 91761 Palaiseau (France); École Polytechnique, Département de Physique, 91128 Palaiseau (France)

    2015-12-21

    We study disordered arrays of metal-insulator-metal nanoantenna in order to create a diffractionless metasurface able to absorb light in the 3–5 μm spectral range. This study is conducted with angle-resolved reflectivity measurements obtained with a Fourier transform infrared spectrometer. A first design is based on a perturbation of a periodic arrangement, leading to a significant reduction of the radiative losses. Then, a random assembly of nanoantennas is built following a Poisson-disk distribution of given density, in order to obtain a nearly perfect cluttered assembly with optical properties of a homogeneous material.

  11. 21 CFR 880.6025 - Absorbent tipped applicator.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Absorbent tipped applicator. 880.6025 Section 880... Devices § 880.6025 Absorbent tipped applicator. (a) Identification. An absorbent tipped applicator is a device intended for medical purposes that consists of an absorbent swab on a wooden, paper, or...

  12. 21 CFR 880.5300 - Medical absorbent fiber.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Medical absorbent fiber. 880.5300 Section 880.5300... Devices § 880.5300 Medical absorbent fiber. (a) Identification. A medical absorbent fiber is a device...'s body surface. Absorbent fibers intended solely for cosmetic purposes are not included in...

  13. 蒙台梭利教育思想对当代幼儿园课程的设计的启示--《有吸收力的心灵》%The Enlightenment of Designing Kindergarten Curriculum Under the Ideas of Montessori ’s There Absorbent Mind

    Institute of Scientific and Technical Information of China (English)

    廖唐兰; 成云

    2014-01-01

    The study of Montessori can be traced back to the 1980s in China. As time flies, more and more people begin to care Montessori and her ideas about kindergarten education. At the same time,“Montessori hot”spreads from the coast to the interior, spreading from big cities to small cities, extending to the private kindergartens and officical kindergartens. This “heat” is not only found in the thinking of Montessori, but also known for pursuing her teaching tool and the way of using the teaching tool; Mongolia Nursery and Mongolia classes also appear though China… This “heat” can be traced back to Montessori’s There Absorbent Mind, it impacts on the designing classic Montessori kindergarten curriculum. This paper focuses on education ideology in There Absorbent Mind and its influence on designing contemporary kindergarten curriculum, and makes a brief analysis and elaboration.%蒙台梭利在中国的发展可追溯到20世纪80年代,随着时间发展,蒙台梭利在中国幼儿教育界的关注便在持续上涨。所以在此时间,“蒙氏热”的发生从沿海延生到内地,从大城市蔓延到中小城市,从单位办园、私人办园扩展到教育部门办的园。这种“热度”不仅体现在对蒙台梭利教育思想的引进,也体现在全国疯狂的追求蒙台梭利玩教把具的使用;还体现在遍地全国的蒙台梭利幼儿园,蒙台梭利教学实验班……这种“热度”细琢磨下来,就可以追踪到蒙台梭利经典著作之《有吸收力的心灵》对我国幼儿园课程设计的影响上来。本文作者将着眼于《有吸收力的心灵》这部经典的巨作中有关蒙台梭利的教育思想及其对我过当代幼儿园课程设计的影响,并将此做必要的分析和阐述。

  14. Can polar bear hairs absorb environmental energy?

    OpenAIRE

    He Ji-Huan; Wang Qing-Li; Sun Jie

    2011-01-01

    A polar bear (Ursus maritimus) has superior ability to survive in harsh Arctic regions, why does the animal have such an excellent thermal protection? The present paper finds that the unique labyrinth cavity structure of the polar bear hair plays an important role. The hair can not only prevent body temperature loss but can also absorb energy from the environment.

  15. Can polar bear hairs absorb environmental energy?

    Directory of Open Access Journals (Sweden)

    He Ji-Huan

    2011-01-01

    Full Text Available A polar bear (Ursus maritimus has superior ability to survive in harsh Arctic regions, why does the animal have such an excellent thermal protection? The present paper finds that the unique labyrinth cavity structure of the polar bear hair plays an important role. The hair can not only prevent body temperature loss but can also absorb energy from the environment.

  16. Timing the warm absorber in NGC 4051

    CERN Document Server

    Silva, Catia; Costantini, Elisa

    2016-01-01

    We investigated, using spectral-timing analysis, the characterization of highly ionized outflows in Seyfert galaxies, the so-called warm absorbers. Here, we present our results on the extensive ~ 600 ks of XMM-Newton archival observations of the bright and highly variable Seyfert 1 galaxy NGC 4051, whose spectrum has revealed a complex multicomponent wind. Making use of both RGS and EPIC-pn data, we performed a detailed analysis through a time-dependent photoionization code in combination with spectral and Fourier spectral-timing techniques. The source light curves and the warm absorber parameters obtained from the data were used to simulate the response of the gas due to variations in the ionizing flux of the central source. The resulting time variable spectra were employed to predict the effects of the warm absorber on the time lags and coherence of the energy dependent light curves. We have found that, in the absence of any other lag mechanisms, a warm absorber with the characteristics of the one observed ...

  17. Methods of calculating radiation absorbed dose.

    Science.gov (United States)

    Wegst, A V

    1987-01-01

    The new tumoricidal radioactive agents being developed will require a careful estimate of radiation absorbed tumor and critical organ dose for each patient. Clinical methods will need to be developed using standard imaging or counting instruments to determine cumulated organ activities with tracer amounts before the therapeutic administration of the material. Standard MIRD dosimetry methods can then be applied.

  18. Microstructured extremely thin absorber solar cells

    DEFF Research Database (Denmark)

    Biancardo, Matteo; Krebs, Frederik C

    2007-01-01

    In this paper we present the realization of extremely thin absorber (ETA) solar cells employing conductive glass substrates functionalized with TiO2 microstructures produced by embossing. Nanocrystalline or compact TiO2 films on Indium doped tin oxide (ITO) glass substrates were embossed...

  19. Semiconductor saturable absorbers for ultrafast terahertz signals

    DEFF Research Database (Denmark)

    Hoffmann, Matthias C.; Turchinovich, Dmitry

    2010-01-01

    We demonstrate saturable absorber behavior of n-type semiconductors GaAs, GaP, and Ge in the terahertz THz frequency range at room temperature using nonlinear THz spectroscopy. The saturation mechanism is based on a decrease in electron conductivity of semiconductors at high electron momentum...

  20. Moving core beam energy absorber and converter

    Science.gov (United States)

    Degtiarenko, Pavel V.

    2012-12-18

    A method and apparatus for the prevention of overheating of laser or particle beam impact zones through the use of a moving-in-the-coolant-flow arrangement for the energy absorbing core of the device. Moving of the core spreads the energy deposition in it in 1, 2, or 3 dimensions, thus increasing the effective cooling area of the device.

  1. The use of a reference absorber for absorption measurements in a reverberation chamber

    DEFF Research Database (Denmark)

    Nolan, Melanie; Vercammen, Martijn; Jeong, Cheol-Ho

    2014-01-01

    and the differences in the results between laboratories are much larger than can be accepted from a jurisdictional point of view. Actions should therefore be taken to reduce the spread. The intention of this paper is to set requirements on the diffusivity of the sound field and to apply a reference absorber, which...... will be used for qualification of the room and correction of the results. The present research establishes the requirements for a proper design of such an absorber and its reference absorption data. The diffuse field factor was used to quantify the diffuse sound field in several reverberation rooms....... Furthermore, calculations and measurements were conducted to optimise the reference absorber. A small round r obin test was performed with this reference absorber in five European laboratories . The results of this research will be used in the proposal for the new ISO 354....

  2. Absorber and emitter for solar thermo-photovoltaic systems to achieve efficiency exceeding the Shockley-Queisser limit.

    Science.gov (United States)

    Rephaeli, Eden; Fan, Shanhui

    2009-08-17

    We present theoretical considerations as well as detailed numerical design of absorber and emitter for Solar Thermophotovoltaics (STPV) applications. The absorber, consisting of an array of tungsten pyramids, was designed to provide near-unity absorptivity over all solar wavelengths for a wide angular range, enabling it to absorb light effectively from solar sources regardless of concentration. The emitter, a tungsten slab with Si/SiO(2) multilayer stack, provides a sharp emissivity peak at the solar cell band-gap while suppressing emission at lower frequencies. We show that, under a suitable light concentration condition, and with a reasonable area ratio between the emitter and absorber, a STPV system employing such absorber-emitter pair and a single-junction solar cell can attain efficiency that exceeds the Shockley-Queisser limit.

  3. Absorbed fractions for electrons in ellipsoidal volumes

    Science.gov (United States)

    Amato, E.; Lizio, D.; Baldari, S.

    2011-01-01

    We applied a Monte Carlo simulation in Geant4 in order to calculate the absorbed fractions for monoenergetic electrons in the energy interval between 10 keV and 2 MeV, uniformly distributed in ellipsoids made from soft tissue. For each volume, we simulated a spherical shape, four oblate and four prolate ellipsoids, and one scalene shape. For each energy and for every geometrical configuration, an analytical relationship between the absorbed fraction and a 'generalized radius' was found, and the dependence of the fit parameters from electron energy is discussed and fitted by proper parametric functions. With the proposed formulation, the absorbed fraction for electrons in the 10-2000 keV energy range can be calculated for all volumes and for every ellipsoidal shape of practical interest. This method can be directly applied to evaluation of the absorbed fraction from the radionuclide emission of monoenergetic electrons, such as Auger or conversion electrons. The average deposited energy per disintegration in the case of extended beta spectra can be evaluated through integration. Two examples of application to a pure beta emitter such as 90Y and to 131I, whose emission include monoenergetic and beta electrons plus gamma photons, are presented. This approach represent a generalization of our previous studies, allowing a comprehensive treatment of absorbed fractions from electron and photon sources uniformly distributed in ellipsoidal volumes of any ellipticity and volume, in the whole range of practical interest for internal dosimetry in nuclear medicine applications, as well as in radiological protection estimations of doses from an internal contamination.

  4. Design

    DEFF Research Database (Denmark)

    Volf, Mette

    This publication is unique in its demystification and operationalization of the complex and elusive nature of the design process. The publication portrays the designer’s daily work and the creative process, which the designer is a part of. Apart from displaying the designer’s work methods...... and design parameters, the publication shows examples from renowned Danish design firms. Through these examples the reader gets an insight into the designer’s reality....

  5. Incorporating piezoelectric energy harvester in tunable vibration absorber for application in multi-modal vibration reduction of a platform structure

    Science.gov (United States)

    Lee, Chun-Ying; Lin, Jia-Hong

    2017-02-01

    Tunable vibration absorber is an effective device to reduce the vibration of structure subjected to harmonic excitation. The vibration energy is transferred mostly to the absorber when the natural frequency of the absorber is tuned to the excitation frequency. In this study, a piezoelectric (PZT) transducer was incorporated into the absorber in order to harvest the vibration energy and still alleviate the vibration of a platform structure. The tuning in dynamic characteristics of the absorber was facilitated by controlling its tip mass. The design formulation of the absorber was presented with a single degree-of-freedom (SDOF) model having the equivalent parameters. In the meantime, an optimal electric load resistor was determined to maximize the power output from the PZT transducer. The experimental measurement validated the SDOF model with good accuracy both in the vibration response and the output electric voltage. Finally, the absorber was installed on a platform structure to investigate its vibration reduction and energy harvesting capability for the external disturbance frequency covering certain frequency span. With three resonance modes of the platform studied, the absorber was able to reduce more than 80% of its original vibration and harvest several folds of electric power comparing with the untuned absorber. Although the performance in vibration reduction was slightly influenced (sensor or actuator applications.

  6. Solar Biogas Digester with Built-In Reverse Absorber Heater

    Directory of Open Access Journals (Sweden)

    Khasan S. Karimov

    2013-01-01

    Full Text Available In this work the design, fabrication and investigation of a solar biogas digester with built-in RAH (Reverse Absorber Heater is presented. The maximum temperature (50 o C inside of the methane tank was taken as a main parameter at the design of the digester. Using energy balance equation for the case of a static mass of fluid being heated; the parameters of thermal insulation of the methane tank were counted. The biogas digester is consisting of methane tank with built-in solar RAH to utilize solar energy for the heating of the slurry prepared from the different organic wastes (dung, sewage, food wastes etc. The methane tank was filled up to 70% of volume by organic wastes of the GIK Institute sewage, firstly, and secondly, by sewage and cow dung as well. During three months (October-December, 2009 and two months (February-March, 2010 the digester was investigated. The solar irradiance incident to the absorber, slurry's temperature and ambient temperature were measured. It was found that using sewage only and sewage with cow dung the retention times was 4 weeks and two weeks respectively and biogas quantity produced was 0.4 and 8.0 m 3 respectively. In addition, biogas upgradation scheme for removal of carbon dioxide, hydrogen sulphide and water vapor from biogas and conversion of biogas energy conversion into electric power is also discussed.

  7. 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......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...

  8. 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.

  9. Absorbing angles, Steiner minimal trees, and antipodality

    CERN Document Server

    Martini, Horst; de Wet, P Oloff; 10.1007/s10957-009-9552-1

    2011-01-01

    We give a new proof that a star $\\{op_i:i=1,...,k\\}$ in a normed plane is a Steiner minimal tree of its vertices $\\{o,p_1,...,p_k\\}$ if and only if all angles formed by the edges at o are absorbing [Swanepoel, Networks \\textbf{36} (2000), 104--113]. The proof is more conceptual and simpler than the original one. We also find a new sufficient condition for higher-dimensional normed spaces to share this characterization. In particular, a star $\\{op_i: i=1,...,k\\}$ in any CL-space is a Steiner minimal tree of its vertices $\\{o,p_1,...,p_k\\}$ if and only if all angles are absorbing, which in turn holds if and only if all distances between the normalizations $\\frac{1}{\\|p_i\\|}p_i$ equal 2. CL-spaces include the mixed $\\ell_1$ and $\\ell_\\infty$ sum of finitely many copies of $R^1$.

  10. Preparation of perlite-based carbon dioxide absorbent.

    Science.gov (United States)

    He, H; Wu, L; Zhu, J; Yu, B

    1994-02-01

    A new highly efficient carbon dioxide absorbent consisting of sodium hydroxide, expanded perlite and acid-base indicator was prepared. The absorption efficiency, absorption capacity, flow resistance and color indication for the absorbent were tested and compared with some commercial products. The absorbent can reduce the carbon dioxide content in gases to 3.3 ppb (v/v) and absorbs not less than 35% of its weight of carbon dioxide. Besides its large capacity and sharp color indication, the absorbent has an outstanding advantage of small flow resistance in comparison with other commercial carbon dioxide absorbents. Applications in gas analysis and purification were also investigated.

  11. VUV Absorbing Vapours in n-Perfluorocarbons

    CERN Document Server

    Albrecht, E; Bellunato, T F; Bressan, A; Dalla Torre, S; D'Ambrosio, C; Davenport, M; Dragicevic, M; Duarte-Pinto, S; Fauland, P; Ilie, S; Lenzen, Georg; Pagano, P; Piedigrossi, D; Tessarotto, F; Ullaland, O

    2003-01-01

    The optical transparency of perfluorocarbons used as Cherenkov media is of prime importance to many Ring Imaging Cherenkov detectors. We will in this paper show that the main photon absorbers in these fluids are hydrocarbons with double or triple bonds. We will moreover discuss a process which can eliminate these pollutants and restore the intrinsic excellent optical transparency of these fluids in the VUV range.

  12. 2D Saturable Absorbers for Fibre Lasers

    Directory of Open Access Journals (Sweden)

    Robert I. Woodward

    2015-11-01

    Full Text Available Two-dimensional (2D nanomaterials are an emergent and promising platform for future photonic and optoelectronic applications. Here, we review recent progress demonstrating the application of 2D nanomaterials as versatile, wideband saturable absorbers for Q-switching and mode-locking fibre lasers. We focus specifically on the family of few-layer transition metal dichalcogenides, including MoS2, MoSe2 and WS2.

  13. Oxygen absorbers in food preservation: a review

    OpenAIRE

    Cichello, Simon Angelo

    2014-01-01

    The preservation of packaged food against oxidative degradation is essential to establish and improve food shelf life, customer acceptability, and increase food security. Oxygen absorbers have an important role in the removal of dissolved oxygen, preserving the colour, texture and aroma of different food products, and importantly inhibition of food spoilage microbes. Active packaging technology in food preservation has improved over decades mostly due to the sealing of foods in oxygen imperme...

  14. Controllability analysis and testing of a novel magnetorheological absorber for field gun recoil mitigation

    Science.gov (United States)

    Ouyang, Qing; Zheng, Jiajia; Li, Zhaochun; Hu, Ming; Wang, Jiong

    2016-11-01

    This paper aims to analyze the effects of combined working coils of magnetorheological (MR) absorber on the shock mitigation performance and verify the controllability of MR absorber as applied in the recoil system of a field gun. A physical scale model of the field gun is established and a long-stroke MR recoil absorber with four-stage parallel electromagnetic coils is designed to apply separate current to each stage and generate variable magnetic field distribution in the annular flow channel. Based on dynamic analysis and firing stability conditions of the field gun, ideal recoil force-stroke profiles of MR absorber at different limiting firing angles are obtained. The experimental studies are carried out on an impact test rig under different combinations of current loading: conventional unified control mode, separate control mode and timing control mode. The fullness degree index (FDI) is defined as the quantitative evaluation criterion of the controllability of MR absorber during the whole recoil motion. The results show that the force-stroke profile of the novel MR absorber can approach the ideal curve within 25 degrees of the limiting firing angle through judicious exploitation of the adjustable rheological properties of MR fluid.

  15. RANS Simulation of the Heave Response of a Two-Body Floating Point Wave Absorber: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Y.; Li, Y.

    2011-03-01

    A preliminary study on a two-body floating wave absorbers is presented in this paper. A Reynolds-Averaged Navier-Stokes computational method is applied for analyzing the hydrodynamic heave response of the absorber in operational wave conditions. The two-body floating wave absorber contains a float section and a submerged reaction section. For validation purposes, our model is first assumed to be locked. The two sections are forced to move together with each other. The locked single body model is used in a heave decay test, where the RANS result is validated with the experimental measurement. For the two-body floating point absorber simulation, the two sections are connected through a mass-spring-damper system, which is applied to simulate the power take-off mechanism under design wave conditions. Overall, the details of the flow around the absorber and its nonlinear interaction with waves are investigated, and the power absorption efficiency of the two-body floating wave absorber in waves with a constant value spring-damper system is examined.

  16. 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.

  17. The characteristic of power flow in broad band dynamic vibration absorber

    Institute of Scientific and Technical Information of China (English)

    WANG Minqing; SHENG Meiping; SUN Jincai; LIU Yi

    2002-01-01

    DVA (dynamic vibration absorber) is good for restrain of the resonance vibration in low frequency, especially under the condition that there are only one mode or two modes in a frequency band. It seems rather difficult to control the resonance vibration of elastic structures in high frequency, since usually there are so many modes in high frequency band. The broad band DVA is brought forward to reduce the resonance vibration of elastic structures. The broad band DVA is designed on the basis of the characteristic of power flow in structure in this paper.The broad band DVA is effective on absorbing the resonance vibration power flow of the mostimportant modes. The ability of absorbing vibration for the broad band DVA is analyzed indetail. The results obtained in this paper provide a basis for the optimization design of thebroad band DVA and the optimization positions on structures.

  18. Modeling the Effect of Polychromatic Light in Quantitative Absorbance Spectroscopy

    Science.gov (United States)

    Smith, Rachel; Cantrell, Kevin

    2007-01-01

    Laboratory experiment is conducted to give the students practical experience with the principles of electronic absorbance spectroscopy. This straightforward approach creates a powerful tool for exploring many of the aspects of quantitative absorbance spectroscopy.

  19. Material Model Evaluation of a Composite Honeycomb Energy Absorber

    Science.gov (United States)

    Jackson, Karen E.; Annett, Martin S.; Fasanella, Edwin L.; Polanco, Michael A.

    2012-01-01

    A study was conducted to evaluate four different material models in predicting the dynamic crushing response of solid-element-based models of a composite honeycomb energy absorber, designated the Deployable Energy Absorber (DEA). Dynamic crush tests of three DEA components were simulated using the nonlinear, explicit transient dynamic code, LS-DYNA . In addition, a full-scale crash test of an MD-500 helicopter, retrofitted with DEA blocks, was simulated. The four material models used to represent the DEA included: *MAT_CRUSHABLE_FOAM (Mat 63), *MAT_HONEYCOMB (Mat 26), *MAT_SIMPLIFIED_RUBBER/FOAM (Mat 181), and *MAT_TRANSVERSELY_ANISOTROPIC_CRUSHABLE_FOAM (Mat 142). Test-analysis calibration metrics included simple percentage error comparisons of initial peak acceleration, sustained crush stress, and peak compaction acceleration of the DEA components. In addition, the Roadside Safety Verification and Validation Program (RSVVP) was used to assess similarities and differences between the experimental and analytical curves for the full-scale crash test.

  20. Ultra-broadband microwave metamaterial absorber based on resistive sheets

    Science.gov (United States)

    Kim, Y. J.; Yoo, Y. J.; Hwang, J. S.; Lee, Y. P.

    2017-01-01

    We investigate a broadband perfect absorber for microwave frequencies, with a wide incident angle, using resistive sheets, based on both simulation and experiment. The absorber uses periodically-arranged meta-atoms, consisting of snake-shape metallic patterns and metal planes separated by three resistive sheet layers between four dielectric layers. We demonstrate the mechanism of the broadband by impedance matching with free space, and the distribution of surface currents at specific frequencies. In simulation, the absorption was over 96% in 1.4-6.0 GHz. The corresponding experimental absorption band over 96% was 1.4-4.0 GHz, however, the absorption was lower than 96% in the 4.0-6.0 GHz range because of the rather irregular thickness of the resistive sheets. Furthermore, it works for wide incident angles and is relatively independent of polarization. The design is scalable to smaller sizes in the THz range. The results of this study show potential for real applications in prevention of microwave frequency exposure, with devices such as cell phones, monitors, and microwave equipment.

  1. Laterally assembled nanowires for ultrathin broadband solar absorbers.

    Science.gov (United States)

    Song, Kyung-Deok; Kempa, Thomas J; Park, Hong-Gyu; Kim, Sun-Kyung

    2014-05-05

    We studied optical resonances in laterally oriented Si nanowire arrays by conducting finite-difference time-domain simulations. Localized Fabry-Perot and whispering-gallery modes are supported within the cross section of each nanowire in the array and result in broadband light absorption. Comparison of a nanowire array with a single nanowire shows that the current density (J(SC)) is preserved for a range of nanowire morphologies. The J(SC) of a nanowire array depends on the spacing of its constituent nanowires, which indicates that both diffraction and optical antenna effects contribute to light absorption. Furthermore, a vertically stacked nanowire array exhibits significantly enhanced light absorption because of the emergence of coupled cavity-waveguide modes and the mitigation of a screening effect. With the assumption of unity internal quantum efficiency, the J(SC) of an 800-nm-thick cross-stacked nanowire array is 14.0 mA/cm², which yields a ~60% enhancement compared with an equivalent bulk film absorber. These numerical results underpin a rational design strategy for ultrathin solar absorbers based on assembled nanowire cavities.

  2. Simulation of shock absorbing materials loaded by drop weights

    Energy Technology Data Exchange (ETDEWEB)

    Kasparek, Eva; Voelzke, Holger; Scheidemann, Robert [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany)

    2013-08-15

    The numerical simulation of transport and storage casks for radioactive waste in accidental scenarios requires adequate material models and input parameters for all relevant structural cask elements, the impact foundation as well as possibly further components involved in the incident. They form the basis for reliable analysis of different loading situations allowing substituting, at least in parts, experimental investigations that are needed in safety reports submitted for nuclear licensing procedures. Hereby, the efficiency of the energy absorbing components, such as cask impact limiters or equivalent structures placed onto or into the foundation of storage buildings, determine to a large extend the performance and thus the design of the casks. The limiters, which are usually made of wood, polyurethane foam (PUF) or damping concrete, are subjected to major plastic deformations, whose distribution and magnitude strongly depend on loading speed, course and temperature. Consequently, it is necessary to establish a systematic data basis and implement this information in advanced numerical material formulations in order to enable finite element simulations to account for all relevant factors. Since the end of 2008, BAM (Bundesanstalt fuer Materialforschung und -pruefung) is supported by the Federal Ministry of Education and Research in order to determine such experimental data as well as to adapt and develop qualified material models for shock absorbing materials in the framework of a project called ENREA. (orig.)

  3. Slow and Fast Light in an Electro-Absorber

    DEFF Research Database (Denmark)

    Öhman, Filip; Bermejo Ramirez, Andres; Sales, Salvador

    2006-01-01

    We demonstrate controllable and large time delay in cascaded semiconductor saturable absorbers and amplifiers. The possibility of further increasing the tuneable phase shift by utilizing field screening effects in the quantum well absorber is demonstrated.......We demonstrate controllable and large time delay in cascaded semiconductor saturable absorbers and amplifiers. The possibility of further increasing the tuneable phase shift by utilizing field screening effects in the quantum well absorber is demonstrated....

  4. Method for absorbing an ion from a fluid

    Science.gov (United States)

    Gao, Huizhen; Wang, Yifeng; Bryan, Charles R.

    2007-07-03

    A method for absorbing an ion from a fluid by using dispersing an organic acid into an anion surfactant solution, mixing in a divalent-metal containing compound and a trivalent-metal containing compound and calcining the resulting solid layered double hydroxide product to form an absorbent material and then contacting the absorbent material with an aqueous solution of cations or anions to be absorbed.

  5. 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.

  6. 21 CFR 868.5300 - Carbon dioxide absorbent.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Carbon dioxide absorbent. 868.5300 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5300 Carbon dioxide absorbent. (a) Identification. A carbon dioxide absorbent is a device intended for medical purposes that consists of...

  7. 21 CFR 868.5310 - Carbon dioxide absorber.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Carbon dioxide absorber. 868.5310 Section 868.5310...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5310 Carbon dioxide absorber. (a) Identification. A carbon dioxide absorber is a device that is intended for medical purposes and that is used in...

  8. Adaptive Seat Energy Absorbers for Enhanced Crash Safety: Technology Demonstration

    Science.gov (United States)

    2016-08-01

    ARL-TR-7743 ● AUG 2016 US Army Research Laboratory Adaptive Seat Energy Absorbers for Enhanced Crash Safety: Technology...AUG 2016 US Army Research Laboratory Adaptive Seat Energy Absorbers for Enhanced Crash Safety: Technology Demonstration by Muthuvel...COVERED (From - To) 10 January 2012–29 February 2016 4. TITLE AND SUBTITLE Adaptive Seat Energy Absorbers for Enhanced Crash Safety: Technology

  9. About sound mufflers sound-absorbing panels aircraft engine

    Science.gov (United States)

    Dudarev, A. S.; Bulbovich, R. V.; Svirshchev, V. I.

    2016-10-01

    The article provides a formula for calculating the frequency of sound absorbed panel with a perforated wall. And although the sound absorbing structure is a set of resonators Helmholtz, not individual resonators should be considered in acoustic calculations, and all the perforated wall panel. The analysis, showing how the parameters affect the size and sound-absorbing structures in the absorption rate.

  10. A MICROGAP SURGE ABSORBER FABRICATED USING CONVENTIONAL SEMICONDUCTOR TECHNOLOGY

    Institute of Scientific and Technical Information of China (English)

    李宏; 阮航宇

    2001-01-01

    A new type microgap surge absorber fabricated by only semiconductor technique has in it a special structure silicon chip which forms microgaps for gas discharge with electrodes, and has advantages such as small size, low cost, suitability for mass production besides the desirable characteristics that common microgap surge absorbers have. Applications of this absorber in communication facilities are discussed.

  11. 21 CFR 886.3300 - Absorbable implant (scleral buckling method).

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Absorbable implant (scleral buckling method). 886... SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Prosthetic Devices § 886.3300 Absorbable implant (scleral buckling method). (a) Identification. An absorbable implant (scleral buckling method) is a...

  12. [Absorbable coronary stents. New promising technology].

    Science.gov (United States)

    Erbel, Raimund; Böse, Dirk; Haude, Michael; Kordish, Igor; Churzidze, Sofia; Malyar, Nasser; Konorza, Thomas; Sack, Stefan

    2007-06-01

    Coronary stent implantation started in Germany 20 years ago. In the beginning, the progress was very slow and accelerated 10 years later. Meanwhile, coronary stent implantation is a standard procedure in interventional cardiology. From the beginning of permanent stent implantation, research started to provide temporary stenting of coronary arteries, first with catheter-based systems, later with stent-alone technology. Stents were produced from polymers or metal. The first polymer stent implantation failed except the Igaki-Tamai stent in Japan. Newly developed absorbable polymer stents seem to be very promising, as intravascular ultrasound (IVUS) and optical coherence tomography have demonstrated. Temporary metal stents were developed based on iron and magnesium. Currently, the iron stent is tested in peripheral arteries. The absorbable magnesium stent (Biotronik, Berlin, Germany) was tested in peripheral arteries below the knee and meanwhile in the multicenter international PROGRESS-AMS (Clinical Performance and Angiographic Results of Coronary Stenting with Absorbable Metal Stents) study. The first magnesium stent implantation was performed on July 30, 2004 after extended experimental testing in Essen. The magnesium stent behaved like a bare-metal stent with low recoil of 5-7%. The stent struts were absorbed when tested with IVUS. Stent struts were not visible by fluoroscopy or computed tomography (CT) as well as magnetic resonance imaging (MRI). That means, that the magnesium stent is invisible and therefore CT and MRI can be used for imaging of interventions. Only using micro-CT the stent struts were visible. The absorption process could be demonstrated in a patient 18 days after implantation due to suspected acute coronary syndrome, which was excluded. IVUS showed a nice open lumen. Stent struts were no longer visible, but replaced by tissue indicating the previous stent location. Coronary angiography after 4 months showed an ischemia-driven target lesion

  13. [Performance of desulfurizing absorbent of roasted navajoite].

    Science.gov (United States)

    Chen, Fang; Yang, Chun-ping; Gan, Hai-ming; Wu, Ting; Chen, Hai-lin; Chen, Hong; Xu, Ke-hui; Xie, Geng-xin

    2010-04-01

    An innovative flue gas desulfurization (FGD) coupling process was proposed in this study to overcome the problems in wet-type limestone/lime processes which include fouling, clogging, and difficulty of selling the by-products and the problems in traditional process for vanadium extraction from navajoite ore such as excessive consumption of sulfuric acid and emissions of pollutants. The performance of a jet bubbling reactor (JBR) at pilot-scale was evaluated using navajoite ore produced in the process of extracting vanadium pentoxide as desulfurization absorbent. Results showed that navajoite ore slurry achieved better desulfurization performance than limestone slurry. When the inlet flue gas pressure drop was 3.0 kPa, the gas flow was about 2350 m3 x h(-1) and the pH of the navajoite ore slurry was higher than 4.5, the desulfurization efficiency was stable about 90%. The SO2 removal efficiency appeared to increase along with the increasing of absorbent cycle-index. The efficiency of the second circulation was improved 3.5% compared to the first circulation. After an operating duration of 40 minutes, the leaching rate of vanadium pentoxide was about 20%, and reached 60% when the by-products were leached with 5% dilute sulfuric acid for 10 hours. The by-product from this process not only could be used to produce vanadium pentoxide which is a valuable industrial product, but also could significantly overcome the pollution problem existing in the traditional refining process of vanadium pentoxide when navajoite ore is used as the feed material. This FGD process using roasted navajoite slurry as absorbent is environmental sound and cost-effective, and shows the potential for application in the field of flue gas desulfurization as well as hydrometallurgy.

  14. DHCAL with Minimal Absorber: Measurements with Positrons

    CERN Document Server

    Freund, B; Repond, J.; Schlereth, J.; Xia, L.; Dotti, A.; Grefe, C.; Ivantchenko, V.; Antequera, J.Berenguer; Calvo Alamillo, E.; Fouz, M.C.; Marin, J.; Puerta-Pelayo, J.; Verdugo, A.; Brianne, E.; Ebrahimi, A.; Gadow, K.; Göttlicher, P.; Günter, C.; Hartbrich, O.; Hermberg, B.; Irles, A.; Krivan, F.; Krüger, K.; Kvasnicka, J.; Lu, S.; Lutz, B.; Morgunov, V.; Provenza, A.; Reinecke, M.; Sefkow, F.; Schuwalow, S.; Tran, H.L.; Garutti, E.; Laurien, S.; Matysek, M.; Ramilli, M.; Schroeder, S.; Bilki, B.; Norbeck, E.; Northacker, D.; Onel, Y.; Cvach, J.; Gallus, P.; Havranek, M.; Janata, M.; Kovalcuk, M.; Kvasnicka, J.; Lednicky, D.; Marcisovsky, M.; Polak, I.; Popule, J.; Tomasek, L.; Tomasek, M.; Sicho, P.; Smolik, J.; Vrba, V.; Zalesak, J.; van Doren, B.; Wilson, G.W.; Kawagoe, K.; Hirai, H.; Sudo, Y.; Suehara, T.; Sumida, H.; Takada, S.; Tomita, T.; Yoshioka, T.; Bilokin, S.; Bonis, J.; Cornebise, P.; Pöschl, R.; Richard, F.; Thiebault, A.; Zerwas, D.; Hostachy, J.Y.; Morin, L.; Besson, D.; Chadeeva, M.; Danilov, M.; Markin, O.; Popova, E.; Gabriel, M.; Goecke, P.; Kiesling, C.; Kolk, N.van der; Simon, F.; Szalay, M.; Corriveau, F.; Blazey, G.C.; Dyshkant, A.; Francis, K.; Zutshi, V.; Kotera, K.; Ono, H.; Takeshita, T.; Ieki, S.; Kamiya, Y.; Ootani, W.; Shibata, N.; Jeans, D.; Komamiya, S.; Nakanishi, H.

    2016-01-01

    In special tests, the active layers of the CALICE Digital Hadron Calorimeter prototype, the DHCAL, were exposed to low energy particle beams, without being interleaved by absorber plates. The thickness of each layer corresponded approximately to 0.29 radiation lengths or 0.034 nuclear interaction lengths, defined mostly by the copper and steel skins of the detector cassettes. This paper reports on measurements performed with this device in the Fermilab test beam with positrons in the energy range of 1 to 10 GeV. The measurements are compared to simulations based on GEANT4 and a standalone program to emulate the detailed response of the active elements.

  15. Absorbency of Superabsorbent Polymers in Cementitious Environments

    DEFF Research Database (Denmark)

    Esteves, Luis Pedro; Jensen, Ole Mejlhede

    2012-01-01

    Optimal use of superabsorbent polymers (SAP) in cement-based materials relies on knowledge on how SAP absorbency is influenced by different physical and chemical parameters. These parameters include salt concentration in the pore fluid, temperature of the system and SAP particle size. The present...... composition of the exposure liquid is investigated with atomic absorption spectroscopy. The paper provides the reader with knowledge about the absorption capacity of SAP in a cementitious environment, and how the absorption process may influence the cement pore fluid....

  16. Design

    DEFF Research Database (Denmark)

    Jensen, Ole B.; Pettiway, Keon

    2017-01-01

    by designers, planners, etc. (staging from above) and mobile subjects (staging from below). A research agenda for studying situated practices of mobility and mobilities design is outlined in three directions: foci of studies, methods and approaches, and epistemologies and frames of thinking. Jensen begins......In this chapter, Ole B. Jensen takes a situational approach to mobilities to examine how ordinary life activities are structured by technology and design. Using “staging mobilities” as a theoretical approach, Jensen considers mobilities as overlapping, actions, interactions and decisions...... with a brief description of how movement is studied within social sciences after the “mobilities turn” versus the idea of physical movement in transport geography and engineering. He then explains how “mobilities design” was derived from connections between traffic and architecture. Jensen concludes...

  17. Design

    DEFF Research Database (Denmark)

    Volf, Mette

    Design - proces & metode iBog®  er enestående i sit fokus på afmystificering og operationalisering af designprocessens flygtige og komplekse karakter. Udgivelsen går bag om designerens daglige arbejde og giver et indblik i den kreative skabelsesproces, som designeren er en del af. Udover et bredt...... indblik i designerens arbejdsmetoder og designparametre giver Design - proces & metode en række eksempler fra anerkendte designvirksomheder, der gør det muligt at komme helt tæt på designerens virkelighed....

  18. Influence of absorber doping in a-SiC:H/a-Si:H/a-SiGe:H solar cells

    Institute of Scientific and Technical Information of China (English)

    Muhammad Nawaz; Ashfaq Ahmad

    2012-01-01

    This work deals with the design evaluation and influence of absorber doping for a-Si:H/a-SiC:H/a-SiGe:H based thin-film solar cells using a two-dimensional computer aided design (TCAD) tool.Various physical parameters of the layered structure,such as doping and thickness of the absorber layer,have been studied.For reliable device simulation with realistic predictability,the device performance is evaluated by implementing necessary models (e.g.,surface recombinations,thermionic field emission tunneling model for carrier transport at the heterojunction,Schokley-Read Hall recombination model,Auger recombination model,bandgap narrowing effects,doping and temperature dependent mobility model and using Fermi-Dirac statistics).A single absorber with a graded design gives an efficiency of 10.1% for 800 nm thick multiband absorption.Similarly,a tandem design shows an efficiency of 10.4% with a total absorber of thickness of 800 nm at a bandgap of 1.75 eV and 1.0 eV for the top a-Si and bottom a-SiGe component cells.A moderate n-doping in the absorber helps to improve the efficiency while p doping in the absorber degrades efficiency due to a decrease in the Voc (and fill factor) of the device.

  19. Influence of absorber doping in a-SiC:H/a-Si:H/a-SiGe:H solar cells

    Science.gov (United States)

    Nawaz, Muhammad; Ahmad, Ashfaq

    2012-04-01

    This work deals with the design evaluation and influence of absorber doping for a-Si:H/a-SiC:H/a-SiGe:H based thin-film solar cells using a two-dimensional computer aided design (TCAD) tool. Various physical parameters of the layered structure, such as doping and thickness of the absorber layer, have been studied. For reliable device simulation with realistic predictability, the device performance is evaluated by implementing necessary models (e.g., surface recombinations, thermionic field emission tunneling model for carrier transport at the heterojunction, Schokley—Read Hall recombination model, Auger recombination model, bandgap narrowing effects, doping and temperature dependent mobility model and using Fermi—Dirac statistics). A single absorber with a graded design gives an efficiency of 10.1% for 800 nm thick multiband absorption. Similarly, a tandem design shows an efficiency of 10.4% with a total absorber of thickness of 800 nm at a bandgap of 1.75 eV and 1.0 eV for the top a-Si and bottom a-SiGe component cells. A moderate n-doping in the absorber helps to improve the efficiency while p doping in the absorber degrades efficiency due to a decrease in the VOC (and fill factor) of the device.

  20. Heat Transfer Performance of Absorber of Absorption Refrigerating Machine

    Science.gov (United States)

    Kunugi, Yoshifumi; Ouchi, Tomihisa; Usui, Sanpei; Fukuda, Tamio

    Experimental studies on heat transfer performance of absorber for lithium bromide-water absorption refrigerating machine are presented in this paper. Experimental apparatus for 35 kW evaporator and absorber, and outer grooved tubes are used. As a result, over-al1 coefficient of heat transmission of absorber has a maximum value, in the case of heat transfer area ratio of absorber to evaporator, is about 0.8. Heat transfer rate of absorber is increased by 60% by using the outer grooved tube compared with the plane surfaced tube.

  1. Design

    Science.gov (United States)

    Buchanan, Richard; Cross, Nigel; Durling, David; Nelson, Harold; Owen, Charles; Valtonen, Anna; Boling, Elizabeth; Gibbons, Andrew; Visscher-Voerman, Irene

    2013-01-01

    Scholars representing the field of design were asked to identify what they considered to be the most exciting and imaginative work currently being done in their field, as well as how that work might change our understanding. The scholars included Richard Buchanan, Nigel Cross, David Durling, Harold Nelson, Charles Owen, and Anna Valtonen. Scholars…

  2. Design

    DEFF Research Database (Denmark)

    Volf, Mette

    2009-01-01

    Design - proces og metode går bag om designerens arbejde og giver et indblik i den skabelsesproces, som designeren er involveret i. Bogen er enestående, fordi den fokuserer på processens flygtige og komplekse karakter, afmystificerer den og gør den operationel - uden at fjerne dens magi. Ud over...

  3. Perturb and Observe Control for an Embedded Point Pivoted Absorber

    Directory of Open Access Journals (Sweden)

    Gianluca Brando

    2016-11-01

    Full Text Available Marine energy sources represent an attractive and inexhaustible reservoir able to contribute to the fulfillment of the world energy demand in accordance with climate/energy regulatory frameworks. Wave energy converter (WEC integration into the main grid requires both the maximization of the harvested energy and the proper management of the generation variability. The present paper focuses on both these mentioned issues. More specifically, it presents an embedded point pivoted absorber (PPA and its related control strategy aimed at maximizing the harvested energy. Experimental and numerical investigations have been carried out in a wave/towing tank facility in order to derive the design characteristics of the full-scale model and demonstrate the validity and effectiveness of the proposed control strategy.

  4. Warm absorbers in active galactic nuclei

    CERN Document Server

    Reynolds, C S; Reynolds, C S; Fabian, A C

    1995-01-01

    Recent {\\it ASCA} observations confirm the presence of X-ray absorption due to partially ionized gas in many Seyfert 1 galaxies; the so-called warm absorber. Constraints on the location of the warm material are presented with the conclusion that this material lies at radii coincident with, or just outside, the broad-line region. The stability of this warm material to isobaric perturbations under the assumptions of thermal and photoionization equilibrium is also studied. It is shown that there is a remarkably small range of ionization parameter, \\xi, for which the warm absorber state is stable. The robustness of this result to changes in the shape of the primary continuum, the assumed density and optical depth is investigated. Given the constraints on the location and the stability properties of the material, several models for the environments of Seyfert nuclei are discussed. These attempt to explain the presence of significant amounts of partially ionized material. In particular, various models of the broad-...

  5. Possible Quantum Absorber Effects in Cortical Synchronization

    Science.gov (United States)

    Kämpf, Uwe

    The Wheeler-Feynman transactional "absorber" approach was proposed originally to account for anomalous resonance coupling between spatio-temporally distant measurement partners in entangled quantum states of so-called Einstein-Podolsky-Rosen paradoxes, e.g. of spatio-temporal non-locality, quantum teleportation, etc. Applied to quantum brain dynamics, however, this view provides an anticipative resonance coupling model for aspects of cortical synchronization and recurrent visual action control. It is proposed to consider the registered activation patterns of neuronal loops in so-called synfire chains not as a result of retarded brain communication processes, but rather as surface effects of a system of standing waves generated in the depth of visual processing. According to this view, they arise from a counterbalance between the actual input's delayed bottom-up data streams and top-down recurrent information-processing of advanced anticipative signals in a Wheeler-Feynman-type absorber mode. In the framework of a "time-loop" model, findings about mirror neurons in the brain cortex are suggested to be at least partially associated with temporal rather than spatial mirror functions of visual processing, similar to phase conjugate adaptive resonance-coupling in nonlinear optics.

  6. Tunable wideband absorber based on resistively loaded lossy high-impedance surface

    Institute of Scientific and Technical Information of China (English)

    党可征; 时家明; 汪家春; 林志丹; 王启超

    2015-01-01

    A lossy high-impedance surface comprised of two layers of resistive frequency selective surfaces is employed to design a tunable electromagnetic absorber. The tunability is realized through changing the composite unit cell by moving the top layer mechanically. To explain the absorbing mechanism, an equivalent circuit model with an interacting coefficient is proposed. Then, simulations and measurements are carried out and agree well with each other. Results show that the complex structure with a thickness less than λ0/4 is able to achieve a wideband absorption in a frequency range from 5.90 GHz to 19.73 GHz. Moreover, it is tunable in the operation frequency band.

  7. A selective pyroelectric detector of millimeter-wave radiation with an ultrathin resonant meta-absorber

    Science.gov (United States)

    Paulish, A. G.; Kuznetsov, S. A.

    2016-11-01

    The results of experimental investigations of spectral and amplitude-frequency characteristics for a discrete wavelength-selective pyroelectric detector operating in the millimetric band are presented. The high spectral selectivity is attained due to integrating the detector with a resonant meta-absorber designed for a close-to-unity absorptivity at 140 GHz. It is demonstrated that the use of this meta-absorber provides an opportunity to construct small-sized and inexpensive multispectral polarization-sensitive systems for radiation detection in the range of millimeter and submillimeter waves.

  8. Unified approach to split absorbing boundary conditions for nonlinear Schrödinger equations.

    Science.gov (United States)

    Zhang, Jiwei; Xu, Zhenli; Wu, Xiaonan

    2008-08-01

    An efficient method is proposed for numerical solutions of nonlinear Schrödinger equations on an unbounded domain. Through approximating the kinetic energy term by a one-way equation and uniting it with the potential energy equation, absorbing boundary conditions are designed to truncate the unbounded domain, which are in nonlinear form and can perfectly absorb waves outgoing from the boundaries of the truncated computational domain. The stability of the induced initial boundary value problem defined on the computational domain is examined by a normal mode analysis. Numerical examples are given to illustrate the stable and tractable advantages of the method.

  9. Experimental demonstration of terahertz metamaterial absorbers with a broad and flat high absorption band.

    Science.gov (United States)

    Huang, Li; Chowdhury, Dibakar Roy; Ramani, Suchitra; Reiten, Matthew T; Luo, Sheng-Nian; Taylor, Antoinette J; Chen, Hou-Tong

    2012-01-15

    We present the design, numerical simulations and experimental measurements of terahertz metamaterial absorbers with a broad and flat absorption top over a wide incidence angle range for either transverse electric or transverse magnetic polarization depending on the incident direction. The metamaterial absorber unit cell consists of two sets of structures resonating at different but close frequencies. The overall absorption spectrum is the superposition of individual components and becomes flat at the top over a significant bandwidth. The experimental results are in excellent agreement with numerical simulations.

  10. Simulation Analysis of Resonant Frequency of Mix Sucker Rod with absorber

    Science.gov (United States)

    Xing, Mingming; Zhou, Lili; Kaifeng, Xue

    2017-03-01

    Considering the influence of sucker rod absorber (SRA) on longitudinal vibration of sucker rod string (SRS), a new model of mix sucker rod with absorber (MSRWA) in the form of numerical integration is built. In the detail, based on the dynamical theory of continuous systems, the wave equation of instantaneous motion of MSRWA is deduced. The dynamic response is solved out with the mode superposition method. The affecting factors of natural frequency are analyzed, such as the length, diameter, density and elastic modulus of SRS. Then three dimensional curves of natural frequency are obtained. The results are very important for the design and application of SRS.

  11. Experimental study of the acoustic characteristics of micro-perforated functional absorbers

    Institute of Scientific and Technical Information of China (English)

    WANG Jiqing; SONG Yongmin; SHENG Shengwo

    2005-01-01

    Micro-perforated panels have been widely used as fiber-free acoustical material for decades in the form of wall or ceiling covering with some air space behind. This paper presents the test study on the acoustical characteristics of two different types of functional absorbers,panel type and tube type, constructed with micro-perforated metal or PVC (polyvinyl chloride) sheets. Acoustical measurements of such functional absorbers in reverberation chamber demonstrate the merit of good absorption as expected. They are not only cost effective in construction and installation, but also appealing esthetically for architectural interior design.

  12. 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.

  13. Absorber Alignment Measurement Tool for Solar Parabolic Trough Collectors: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Stynes, J. K.; Ihas, B.

    2012-04-01

    As we pursue efforts to lower the capital and installation costs of parabolic trough solar collectors, it is essential to maintain high optical performance. While there are many optical tools available to measure the reflector slope errors of parabolic trough solar collectors, there are few tools to measure the absorber alignment. A new method is presented here to measure the absorber alignment in two dimensions to within 0.5 cm. The absorber alignment is measured using a digital camera and four photogrammetric targets. Physical contact with the receiver absorber or glass is not necessary. The alignment of the absorber is measured along its full length so that sagging of the absorber can be quantified with this technique. The resulting absorber alignment measurement provides critical information required to accurately determine the intercept factor of a collector.

  14. Establishment of ANEDr model for evaluating absorbed-nitrogen effects on wheat dry matter production

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jiao; TAO Hong-bin; LIAO Shu-hua; WANG Pu

    2016-01-01

    Applying mathematic models to evaluate absorbed-N effects on dry matter production at different developmental stages would help determine proper nitrogen management according to crop demands and yield target. Two ifeld trials were car-ried out for establishing absorbed-N effects on dry matter production (ANEDr) model, using uniform design in 2010–2011 and 2012–2013 winter wheat growing seasons in Hebei Province, China. Another ifeld trial was carried out in 2010–2011 for model validation. Dry matter and N concentration in leaf and non-leaf organs were measured at setting, jointing, an-thesis, and maturity. Theory of best linear unbiased prediction (BLUP) was applied to analyse the N effects of leaf and non-leaf organs on dry matter production. Within ANEDr model, four N-affected phases at each stage were concerned, leaf absorbed-N effect before this stage, non-leaf organ absorbed-N effect before this stage,leaf absorbed-N effect at this stage, and non-leaf organ absorbed-N effect at this stage. In addition, developmental processes, genotype characters and temperature were three factors that determine each N effect. It was demonstrated that ANEDr model can precisely quantify absorbed-N effects on dry matter production with high correlation coefifcient (r=0.95). Comparing with other models, ANEDr model considered both leaf and non-leaf organs according to developmental processes of winter wheat, showed higher lfexibility and simplicity, thus could be applied to different environments, cultivars and crops after parameter adjustment.

  15. THERMAL FINITE ELEMENT ANALYSIS X9 AND X29 X-RAY RING CROTCH RADIATION ABSORBERS.

    Energy Technology Data Exchange (ETDEWEB)

    MERCADO-CORUJO,H.

    1999-08-11

    This report details the efforts by engineers at the National Synchrotron Light Source (NSLS) of Brookhaven National Laboratory (BNL) to evaluate the reliability of water-cooled radiation absorbers used in the NSLS X-ray ring. The absorbers on this report are part of the X-9 and X-29 dipole vacuum chambers. The absorbers are located at the intersection (crotch) of the beamline exit ports with the electron beam chamber, and are generally referred to as ''crotches''. The purpose of this analysis was to demonstrate the thermal reliability of the crotches under operating conditions that will be present over the expected life of the ring. The efforts described include general engineering layouts, engineering calculations, finite element analysis (FEA), results and conclusions of the analysis, and future design recommendations.

  16. Recommended method for measurement of absorbency of superabsorbent polymers in cement-based materials

    DEFF Research Database (Denmark)

    Esteves, Luis Pedro

    2015-01-01

    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......The application of superabsorbent polymers in concrete technology is now becoming a reality in several places in the world. Independently of the specific technical application involving any of the hydrogels, the design of cement-based materials requires that the knowledge on the absorbency......—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...

  17. Effects of weld damage on the dynamics of energy absorbing lanyards.

    Science.gov (United States)

    Katona, David N; Bennett, Charlie R; McKoryk, Michael; Brisson, Andre L; Sparrey, Carolyn J

    2017-01-26

    Manufacturers recommend removing fall protection system components from service for any indication of weld spatter or tool damage; however, little is known about the specific effects of lanyard damage on fall arrest dynamics. Thirty-two energy absorbing lanyards were drop tested after being damaged with weld spatter, plasma torches and cutting tools and compared with new, undamaged lanyards. Two lanyards damaged with a plasma torch failed completely without deploying the energy absorber while weld spatter damage and tool cuts, up to 2/3 through the width of the webbing, had no effect on fall arrest dynamics. The results highlight the catastrophic implications of high temperature damage to lanyard webbing resulting from plasma torches - which require immediate removal from service. In addition, the integrated energy absorber design in bungee style lanyards makes them more susceptible to damage anywhere along its length. We therefore recommended against bungee lanyards for ironworkers and welders.

  18. Electromagnetic resonances of solar-selective absorbers with nanoparticle arrays embedded in a dielectric layer

    Science.gov (United States)

    Sakurai, Atsushi; Kawamata, Tomoaki

    2016-11-01

    We numerically investigate a solar-selective absorber with tungsten core-shell nanoparticle arrays embedded in an SiO2 layer. The 3D full-wave finite-difference time-domain (FDTD) simulations are performed to investigate the geometric effects of different types of solar-selective absorbers. Consequently, broadband light absorption was achieved with either a tungsten nanoparticle array or a tungsten core-shell nanoparticle array because of the strong electric field enhancement in the gap between the core nanoparticles. The solar performance of the proposed structure is shown for high-efficiency solar light absorption. This study enhances understanding of the light absorption mechanism of metallic nanoparticle/dielectric composite and facilitates the design of high-efficiency solar-selective absorbers.

  19. Estimation of the RF Characteristics of Absorbing Materials in Broad RF Frequency Ranges

    CERN Document Server

    Fandos, R

    2008-01-01

    Absorbing materials are very often used in RF applications. Their electromagnetic characteristics (relative permittivity εr, loss tangent tan δ and conductivity σ) are needed in order to obtain a high-quality design of the absorbing pieces in the frequency range of interest. Unfortunately, suppliers often do not provide these quantities. A simple technique to determine them, based on the RF measurement of the disturbance created by the insertion of a piece of absorber in a waveguide, is presented in this note. Results for samples of two different materials, silicon carbide and aluminum nitride are presented. While the former has a negligible conductivity at the working frequencies, the conductivity of the latter has to be taken into account in order to obtain a meaningful estimation of εr and tan δ. The equations of Kramers & Kronig have been applied to the data as a cross check, confirming the results.

  20. Effects of rubber shock absorber on the flywheel micro vibration in the satellite imaging system

    Science.gov (United States)

    Deng, Changcheng; Mu, Deqiang; Jia, Xuezhi; Li, Zongxuan

    2016-12-01

    When a satellite is in orbit, its flywheel will generate micro vibration and affect the imaging quality of the camera. In order to reduce this effect, a rubber shock absorber is used, and a numerical model and an experimental setup are developed to investigate its effect on the micro vibration in the study. An integrated model is developed for the system, and a ray tracing method is used in the modeling. The spot coordinates and displacements of the image plane are obtained, and the modulate transfer function (MTF) of the system is calculated. A satellite including a rubber shock absorber is designed, and the experiments are carried out. Both simulation and experiments results show that the MTF increases almost 10 %, suggesting the rubber shock absorber is useful to decrease the flywheel vibration.

  1. Analysis of an air cooled ammonia-water vertical tubular absorber

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Seara, J.; Uhia, F.J.; Sieres, J. [Area de Maquinas y Motores Termicos, Escuela Tecnica Superior de Ingenieros Industriales, Campus Lagoas-Marcosende, No 9, 36310 Vigo (Spain)

    2007-03-15

    This paper presents a detailed analysis of an ammonia-water vertical tubular absorber cooled by air. The absorption process takes place co-currently upward inside the tubes. The tubes are externally finned with continuous plate fins and the tube rows are arranged staggered in the direction of the air flow. The air is forced over the tube bank and circulates between the plain fins in cross flow with the ammonia-water mixture. The analysis has been carried out by means of a mathematical model developed on the basis of mass and energy balances and heat and mass transfer equations. The model takes into account separately the churn, slug and bubbly flow patterns experimentally forecasted in this type of absorption processes inside vertical tubes and considers the simultaneous heat and mass transfer processes in both liquid and vapour phases, as well as heat transfer to the cooling air. The model has been implemented in a computer program. Results based on a representative design and nominal operating conditions of an absorber for a small capacity ammonia-water absorption refrigeration system are shown. A parametric analysis was realised to investigate the influence of the design parameters and operating conditions on the absorber performance. The noteworthy results that have effect on practical design of the absorber are presented and commented. (authors)

  2. Relationship Between Absorber Layer Properties and Device Operation Modes For High Efficiency Thin Film Solar Cells

    Science.gov (United States)

    Ravichandran, Ram; Kokenyesi, Robert; Wager, John; Keszler, Douglas; CenterInverse Design Team

    2014-03-01

    A thin film solar cell (TFSC) can be differentiated into two distinct operation modes based on the transport mechanism. Current TFSCs predominantly exploit diffusion to extract photogenerated minority carriers. For efficient extraction, the absorber layer requires high carrier mobilities and long minority carrier lifetimes. Materials exhibiting a strong optical absorption onset near the fundamental band gap allows reduction of the absorber layer thickness to significantly less than 1 μm. In such a TFSC, a strong intrinsic electric field drives minority carrier extraction, resulting in drift-based transport. The basic device configuration utilized in this simulation study is a heterojunction TFSC with a p-type absorber layer. The diffusion/drift device operation modes are simulated by varying the thickness and carrier concentration of the absorber layer, and device performance between the two modes is compared. In addition, the relationship between device operation mode and transport properties, including carrier mobility and minority carrier lifetime are explored. Finally, candidate absorber materials that enable the advantages of a drift-based TFSC developed within the Center for Inverse Design are presented. School of Electrical Engineering and Computer Science.

  3. Absorber Tube with Internal Pin-Fins for Solar Parabolic Trough Collector

    Directory of Open Access Journals (Sweden)

    Kalidasan B.

    2016-01-01

    Full Text Available Solar parabolic trough collectors exploit solar energy for power generation in solar thermal power stations. These systems require long arrays of reflective troughs with absorber tube running along the axis of parabolic dish. A successful attempt to reduce the length of arrays was accomplished by experimentally analysing the modifications done in absorber tube. Two out of three tubes were fabricated and they were employed to obtain the performance parameters through experimentation conducted at VIT University, Vellore, India. Distilled water was used as the working fluid. Maximum efficiency of 39.12% was obtained at 451.6 W/m2 of direct normal irradiance (DNI for absorber tube with internal pin-fins and without glass tube (AFWGt compared to 8.15% obtained at same value of DNI and other conditions for simple absorber tube without glass cover (AWGt. Cylindrical parabolic trough available at the university was utilized, providing the basis for designing and fabrication of the tubes. Plots for varying mass flow rate at interval of 10 minutes were made against instantaneous thermal efficiency and heat utilized, for direct normal irradiance vs. temperature difference across the tubes and instantaneous thermal efficiency. Through the experimentation conducted, better performance was procured compared to earlier works. Thus, the proposal infers that absorber tube with internal fins has good scope for its application, both domestically as well as industrially. It also calls for further research and development of proposed techniques so as to achieve better performance curves.

  4. The Effects Of Antiretroviral Drugs On The Absorbance Characteristics Of Blood Components

    Directory of Open Access Journals (Sweden)

    O. I. Ani

    2015-08-01

    Full Text Available Abstract The effects of antiretroviral drugs on the absorbance characteristics of blood components have been studied. The methodology involved the serial dilution of the five different antiretroviral drugs two HAARTFDC and three single drugs and the subsequent incubation with the blood samples collected from ten blood samples of HIV negative persons for the absorbance measurement using a digital Ultraviolet Visible MetaSpecAE1405031Pro Spectrophotometer. Reflectance Dielectric constant etc were derived from the absorbance data. For these drugs to be effective as HIV blockers they should be able to coat the surfaces of the lymphocytes. The question therefore arises as to what extent these drugs are able to coat the surfaces of the blood cells This was established using the extent of absorbance change. Models for coating effectiveness were formulated. The coating effectiveness was therefore calculated from peak absorbance values. Red blood cells were shown not to give reliable results. The results obtained however establish the fact that some coating of the drug had really occurred on the surfaces of the lymphocytes. The drug films were determined for lymphocytes and used to explain some observed clinical findings. The use of the findings of this work in drug design may be expected to yield good results.

  5. Global Navigation Satellite System Multipath Mitigation Using a Wave-Absorbing Shield.

    Science.gov (United States)

    Yang, Haiyan; Yang, Xuhai; Sun, Baoqi; Su, Hang

    2016-08-22

    Code multipath is an unmanaged error source in precise global navigation satellite system (GNSS) observation processing that limits GNSS positioning accuracy. A new technique for mitigating multipath by installing a wave-absorbing shield is presented in this paper. The wave-absorbing shield was designed according to a GNSS requirement of received signals and collected measurements to achieve good performance. The wave-absorbing shield was installed at the KUN1 and SHA1 sites of the international GNSS Monitoring and Assessment System (iGMAS). Code and carrier phase measurements of three constellations were collected on the dates of the respective installations plus and minus one week. Experiments were performed in which the multipath of the measurements obtained at different elevations was mitigated to different extents after applying the wave-absorbing shield. The results of an analysis and comparison show that the multipath was mitigated by approximately 17%-36% on all available frequencies of BeiDou Navigation Satellite System (BDS), Global Positioning System (GPS), and Global Navigation Satellite System (GLONASS) satellites. The three-dimensional accuracies of BDS, GPS, and GLONASS single-point positioning (SPP) were, respectively, improved by 1.07, 0.63 and 0.49 m for the KUN1 site, and by 0.72, 0.79 and 0.73 m for the SHA1 site. Results indicate that the multipath of the original observations was mitigated by using the wave-absorbing shield.

  6. 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.

  7. An infrared metamaterial selective absorber with emitter considering atmospheric absorption for low observability (Conference Presentation)

    Science.gov (United States)

    Kim, Jagyeong; Han, Kiwook; Hahn, Jae W.

    2016-09-01

    Advancement in stealth technology is very crucial for the protection from enemy. Detection of IR electromagnetic wave is performed by detecting the IR radiation from aircraft fuselage or reflected laser by using laser guided missile. In this research, we designed the metamaterial selective absorber with emitter considering atmospheric absorption to minimize observability from these detecting system. The model is designed as T-asymmetric structure for dual-band absorption or emission, and these two parts can be independently tuned. One part is designed as emitter which emit the radiation in the wavelength region where atmospheric absorption is strong. In order to select the target wavelength region, we used the MODTRAN database to calculate the molecular absorption in the atmosphere and strong absorptions occurs at 2μm, 4μm and 5-8μm wavelength regions. The other part is designed as an absorber which absorbs the IR signal from laser guided missile at 1.064μm. Selective emission or absorption at these wavelength region can be achieved by tuning the geometry of the structure. These mechanisms suppose the thermal equilibrium state so that the Kirchhoff law is satisfied. FDTD simulations of the designed structure was conducted to confirm the electromagnetic resonance. Also, we calculated the detected energy from the designed structure and compared with that from conventional aircraft surface. According to the calculation results, the measured signal from the suggested structure decreases to 1/10 of the signal from conventional surface.

  8. Post-treatments of Super Absorbent Polymer

    Institute of Scientific and Technical Information of China (English)

    LIU Song; ZHOU Xiang; XING Zhi-qi

    2002-01-01

    Properties of high absorbency and modulus (gel rength) were both needed in applications of superabsorbent polymer (SAP). Generally, the absorption characteristic and gel strength reach a crossover point for a given system. Beyond this point, a given property will show improvement at the expense of another property. To synthesize SAP with properties superior to this optimum value, further modification in the process becomes essential. In our post-treatment modification of superabsorbent polymer, neither the variety of the crosslinkers, nor their amount was found the effective factors to the polymer performance, but the liquor ratio of the treating liquid to polymer. The combination of the chemical treating and heat-treating method was also explored. But this didn't put any positive effect on SAP's properties.

  9. Hot Carrier extraction with plasmonic broadband absorbers

    CERN Document Server

    Ng, Charlene; Dligatch, Svetlana; Roberts, Ann; Davis, Timothy J; Mulvaney, Paul; Gomez, Daniel E

    2016-01-01

    Hot charge carrier extraction from metallic nanostructures is a very promising approach for applications in photo-catalysis, photovoltaics and photodetection. One limitation is that many metallic nanostructures support a single plasmon resonance thus restricting the light-to-charge-carrier activity to a spectral band. Here we demonstrate that a monolayer of plasmonic nanoparticles can be assembled on a multi-stack layered configuration to achieve broad-band, near-unit light absorption, which is spatially localised on the nanoparticle layer. We show that this enhanced light absorbance leads to $\\sim$ 40-fold increases in the photon-to-electron conversion efficiency by the plasmonic nanostructures. We developed a model that successfully captures the essential physics of the plasmonic hot-electron charge generation and separation in these structures. This model also allowed us to establish that efficient hot carrier extraction is limited to spectral regions where the photons possessing energies higher than the S...

  10. Ultrathin microwave absorber based on metamaterial

    Science.gov (United States)

    Kim, Y. J.; Yoo, Y. J.; Hwang, J. S.; Lee, Y. P.

    2016-11-01

    We suggest that ultrathin broadband metamaterial is a perfect absorber in the microwave regime by utilizing the properties of a resistive sheet and metamaterial. Meta-atoms are composed of four-leaf clover-shape metallic patterns and a metal plane separated by three intermediate resistive sheet layers between four dielectric layers. We interpret the absorption mechanism of the broadband by using the distribution of surface currents at specific frequencies. The simulated absorption was over 99% in 1.8-4.2 GHz. The corresponding experimental absorption was also over 99% in 2.62-4.2 GHz; however, the absorption was slightly lower than 99% in 1.8-2.62 GHz because of the sheet resistance and the changed values for the dielectric constant. Furthermore, it is independent of incident angle. The results of this research indicate the possibility of applications, due to the suppression of noxious exposure, in cell phones, computers and microwave equipments.

  11. 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.

  12. PLD-grown thin film saturable absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Tellkamp, Friedjof

    2012-11-01

    The subject of this thesis is the preparation and characterization of thin films made of oxidic dielectrics which may find their application as saturable absorber in passively Q-switched lasers. The solely process applied for fabrication of the thin films was the pulsed laser deposition (PLD) which stands out against other processes by its flexibility considering the composition of the systems to be investigated. Within the scope of this thesis the applied saturable absorbers can be divided into two fundamentally different kinds of functional principles: On the one hand, saturable absorption can be achieved by ions embedded in a host medium. Most commonly applied bulk crystals are certain garnets like YAG (Y{sub 3}Al{sub 5}O{sub 12}) or the spinel forsterite (Mg{sub 2}SiO{sub 4}), in each case with chromium as dopant. Either of these media was investigated in terms of their behavior as PLD-grown saturable absorber. Moreover, experiments with Mg{sub 2}GeO{sub 4}, Ca{sub 2}GeO{sub 4}, Sc{sub 2}O{sub 3}, and further garnets like YSAG or GSGG took place. The absorption coefficients of the grown films of Cr{sup 4+}:YAG were determined by spectroscopic investigations to be one to two orders of magnitude higher compared to commercially available saturable absorbers. For the first time, passive Q-switching of a Nd:YAG laser at 1064 nm with Cr{sup 4+}:YAG thin films could be realized as well as with Cr:Sc{sub 2}O{sub 3} thin films. On the other hand, the desirable effect of saturable absorption can also be generated by quantum well structures. For this purpose, several layer system like YAG/LuAG, Cu{sub 2}O/MgO, and ZnO/corumdum were investigated. It turned out that layer systems with indium oxide (In{sub 2}O{sub 3}) did not only grew in an excellent way but also showed up a behavior regarding their photo luminescence which cannot be explained by classical considerations. The observed luminescence at roughly 3 eV (410 nm) was assumed to be of excitonic nature and its

  13. Application of Tuned Vibration Absorbers in Fluid Mounts

    Directory of Open Access Journals (Sweden)

    Mohammad Jalali Mashayekhi

    2009-01-01

    Full Text Available The need to reduce the fuel consumption of vehicles leads to having lighter chassis’ with lighter engines yet maintaining engine power. These new design requirements are in contrast with the vibration isolation requirements. To keep the vehicles light yet provide good cabin noise and vibration isolation, requires a new vibration isolation technology. Fluid mounts have been used in the aerospace and the automotive industry to provide cabin noise and vibration reduction for years. With the use of passive fluid mounts, the highest cabin noise and vibration reduction is achieved at a frequency called “Notch Frequency”. But typical passive fluid mounts have only one notch frequency. So the best cabin noise and vibration reduction is only achievable at one frequency. In this paper, a new fluid mount design in combination with a tuned vibration absorber is proposed. Bond graph modelling technique is used to model the new fluid mount design. The physical model and simulation results are presented. The effect of the natural frequency of the TVA on the dynamic stiffness of the fluid mount is studied.

  14. Neutron absorbed dose in a pacemaker CMOS

    Energy Technology Data Exchange (ETDEWEB)

    Borja H, C. G.; Guzman G, K. A.; Valero L, C. Y.; Banuelos F, A.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Paredes G, L., E-mail: candy_borja@hotmail.com [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2011-11-15

    The absorbed dose due to neutrons by a Complementary Metal Oxide Semiconductor (CMOS) has been estimated using Monte Carlo methods. Eventually a person with a pacemaker becomes a patient that must be treated by radiotherapy with a linear accelerator; the pacemaker has integrated circuits as CMOS that are sensitive to intense and pulsed radiation fields. When the Linac is working in Bremsstrahlung mode an undesirable neutron field is produced due to photoneutron reactions; these neutrons could damage the CMOS putting the patient at risk during the radiotherapy treatment. In order to estimate the neutron dose in the CMOS a Monte Carlo calculation was carried out where a full radiotherapy vault room was modeled with a W-made spherical shell in whose center was located the source term of photoneutrons produced by a Linac head operating in Bremsstrahlung mode at 18 MV. In the calculations a phantom made of tissue equivalent was modeled while a beam of photoneutrons was applied on the phantom prostatic region using a field of 10 x 10 cm{sup 2}. During simulation neutrons were isotropically transported from the Linac head to the phantom chest, here a 1 {theta} x 1 cm{sup 2} cylinder made of polystyrene was modeled as the CMOS, where the neutron spectrum and the absorbed dose were estimated. Main damages to CMOS are by protons produced during neutron collisions protective cover made of H-rich materials, here the neutron spectrum that reach the CMOS was calculated showing a small peak around 0.1 MeV and a larger peak in the thermal region, both connected through epithermal neutrons. (Author)

  15. Flexor Tenorrhaphy Using Absorbable Suture Materials

    Directory of Open Access Journals (Sweden)

    Hyung Joo Kang

    2012-07-01

    Full Text Available Background Nonabsorbable sutures are favorable for repairing flexor tendons. However,absorbable sutures have performed favorably in an animal model.Methods Two-strand sutures using the interlocking modified Kessler method with polydioxanoneabsorbable sutures 4-0 were used to repair completely ruptured flexor tendons in 55 fingersfrom 41 consecutive patients. The medical records of average 42 follow up weeks were analyzedretrospectively. The data analyzed using the chi-squared test, and Fisher’s exact test was used forpostoperative complications. The results were compared with those of other studies.Results Among the index, middle, ring, and little fingers were injured in 9, 17, 16, and13 fingers, respectively. The injury levels varied from zone 1 to 5. Of the 55 digits in ourstudy, there were 26 (47% isolated flexor digitorum profundus (FDP injuries and 29 (53%combined FDP and with flexor digitorum superficialis injuries. Pulley repair was also conducted.Concomitant injuries of blood vessels and nerves were found in 17 patients (23 fingers; nerveinjuries occurred in 5 patients (10 fingers. Two patients had ruptures (3.6%, and one patienthad two adhesions (3.6%. Using the original Strickland criteria, all the patients were assessedto be excellent or good. Also, fibrosis and long-term foreign body tissue reactions such as stitchgranuloma were less likely occurred in our study. Compared to the Cullen’s report that usednonabsorbable sutures, there was no significant difference in the rupture or adhesion rates.Conclusions Therefore, this study suggests that appropriate absorbable core sutures can beused safely for flexor tendon repairs.

  16. Large area bismuth absorbers for X-ray microcalorimeters

    Energy Technology Data Exchange (ETDEWEB)

    Vaillancourt, J.E. E-mail: vaillancourt@wisp.physics.wisc.edu; Allen, C.A.; Brekosky, R.; Dosaj, A.; Galeazzi, M.; Kelley, R.; Liu, D.; McCammon, D.; Porter, F.S.; Rocks, L.E.; Sanders, W.T.; Stahle, C.K

    2004-03-11

    Two challenges facing the use of large area (2 mmx2 mm) bismuth absorbers for microcalorimetry are uncertainties in the heat capacity of bismuth and the effects of lateral heat conduction and position dependence due to the absorber's large size. We have measured the heat capacity of three Bi samples to be 0.3-0.6 J K{sup -1} m{sup -3} at 100 mK. These absorbers also exhibit response variations as phonons created by an X-ray event at an absorber edge will take longer to propagate to the thermometer attachment point than those at the absorber center. This effect may degrade the detector's energy resolution if the propagation time is not very short compared to the thermometer time constant. We show that the response of the largest absorber varies by {approx}4% across its area.

  17. Local Structure Analysis of Materials for Solar Cell Absorber Layer

    OpenAIRE

    Jewell, Leila Elizabeth

    2016-01-01

    This dissertation examines solar cell absorber materials that have the potential to replace silicon in solar cells, including several copper-based sulfides and perovskites. Earth-abundant absorbers such as these become even more cost-effective when used in a nanostructured solar cell. Atomic layer deposition (ALD) and chemical vapor deposition (CVD) deposit highly conformal films and hence are important tools for developing extremely thin absorber solar cells with scalability. Thus, the prima...

  18. Tremor Reduction at the Palm of a Parkinson’s Patient Using Dynamic Vibration Absorber

    Directory of Open Access Journals (Sweden)

    Sarah Gebai

    2016-07-01

    Full Text Available Parkinson’s patients suffer from severe tremor due to an abnormality in their central oscillator. Medications used to decrease involuntary antagonistic muscles contraction can threaten their life. However, mechanical vibration absorbers can be used as an alternative treatment. The objective of this study is to provide a dynamic modeling of the human hand that describes the biodynamic response of Parkinson’s patients and to design an effective tuned vibration absorber able to suppress their pathological tremor. The hand is modeled as a three degrees-of-freedom (DOF system describing the flexion motion at the proximal joints on the horizontal plane. Resting tremor is modeled as dual harmonic excitation due to shoulder and elbow muscle activation operating at resonance frequencies. The performance of the single dynamic vibration absorber (DVA is studied when attached to the forearm and compared with the dual DVA tuned at both excitation frequencies. Equations of motion are derived and solved using the complex transfer function of the non-Lagrangian system. The absorber’s systems are designed as a stainless steel alloy cantilevered beam with an attached copper mass. The dual DVA was the most efficient absorber which reduces 98.3%–99.5%, 97.0%–97.3% and 97.4%–97.5% of the Parkinson’s tremor amplitude at the shoulder, elbow and wrist joint.

  19. 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.

  20. 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

    Light Modulator for THz Applications," Advanced Optical Materials, vol. 2, pp. 275-279, 2014. [7] H. Tao, N. I. Landy, C. M. Bingham, X. Zhang, R. D. Averitt, and W. J. Padilla, "A metamaterial absorber for the terahertz regime: Design, fabrication and characterization," Optics Express, vol. 16, pp. 7181-7188, May 12 2008. [8] J. Hao, J. Wang, X. Liu, W. J. Padilla, L. Zhou, and M. Qiu, "High performance optical absorber based on a plasmonic metamaterial," Applied Physics Letters, vol. 96, p. 251104, 2010. [9] X. Liu, T. Tyler, T. Starr, A. F. Starr, N. M. Jokerst, and W. J. Padilla, "Taming the Blackbody with Infrared Metamaterials as Selective Thermal Emitters," Physical Review Letters, vol. 107, p. 045901, 07/18/ 2011. [10] T. Maier and H. Brückl, "Wavelength-tunable microbolometers with metamaterial absorbers," Optics Letters, vol. 34, pp. 3012-3014, 2009/10/01 2009. [11] A. Tittl, P. Mai, R. Taubert, D. Dregely, N. Liu, and H. Giessen, "Palladium-Based Plasmonic Perfect Absorber in the Visible Wavelength Range and Its Application to Hydrogen Sensing," Nano Letters, vol. 11, pp. 4366-4369, 2011/10/12 2011. [12] N. Liu, M. Mesch, T. Weiss, M. Hentschel, and H. Giessen, "Infrared Perfect Absorber and Its Application As Plasmonic Sensor," Nano Letters, vol. 10, pp. 2342-2348, Jul 2010. [13] G. H. Li, X. S. Chen, O. P. Li, C. X. Shao, Y. Jiang, L. J. Huang, et al., "A novel plasmonic resonance sensor based on an infrared perfect absorber," Journal of Physics D-Applied Physics, vol. 45, p. 205102, May 23 2012.

  1. ABSORBENCY CHARACTERISTICS OF PESHTAMALS: TRADITIONAL TURKISH WOVEN CLOTHES

    Directory of Open Access Journals (Sweden)

    KESKIN Reyhan

    2014-05-01

    Full Text Available Absorbency of textiles is defined as the ability of taking in a fluid in the manner of a sponge. Absorbency is required for comfort properties in so me clothes such as sportswear and underwear clothing, for drying properties in napkins, towels and bathrobes, for health concerns in some medical textiles such as bandages, gauze and absorbent cotton, and for cleaning properties in washclothes and mops. In this study five different fabric samples (three woven 100% cotton fabrics A, B and P respectively at plain, twill, and peshtamal weaving patterns and two 100% cotton terry towels T1 and T2 were tested. The absorbency properties of the samples were evaluated according to the droplet test, sinking time test and wicking height tests (pottasium chromate test. Peshtamal samples showed better absorbency results than plain and twill weaves and lower but close results to towel samples according to the droplet test, sinking time test and wicking height tests. The absorbency properties of peshtamals showed results close to towel samples. The void content of peshtamals is higher than plain and twill samples but closer and lower than towel samples. The good absorbency results of peshtamals might be due to the void content of peshtamals which is higher than plain and twill samples but closer and lower than towel samples. Peshtamals which are good in absorbency and light in weight might be used widespreadly in daily life for their high absorbency, and on travel for weight saving purposes.

  2. Simulated mixed absorbers and effective atomic numbers for attenuation

    Indian Academy of Sciences (India)

    K Karunakaran Nair; N Ramachandran; K K Abdullah; K M Varier

    2006-09-01

    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 and also for the simulated absorbers by rotating the targets. ORTEC HPGe and NaI(Tl) detectors were used for detection of -rays.The experimental results compare favourably with theoretical values derived from XCOM package and suggest the usefulness of the concept of effective atomic numbers and the utility of the rotating absorbers technique.

  3. A Study on Hybrid Absorbing Material with Multilayer Metallic Wire Grids%多层金属栅网混合结构吸波特性分析

    Institute of Scientific and Technical Information of China (English)

    韩彦明; 唐守柱; 何丙发

    2013-01-01

    文中采用传输矩阵理论和二端口级联网络分析了多层金属栅网混合结构的吸波特性,通过将多层金属栅网与多层介质阻抗匹配,在介质厚度不变的情况下,明显提高了混合结构的吸收峰值;同时,通过调整每层金属栅网的半径、间距,可调整混合结构吸收峰值位置,给出了典型混合结构的仿真计算结果.结果表明,混合结构吸收峰值可提高6 dB以上,在保证吸收效果的前提下,调整了吸收峰值的位置,可根据要求用于设计不同频段的吸波材料.%Absorbing properties of hybrid material with multilayer metallic wire grids is studied in this paper, with the transfer matrix method and two ports transmission formula of microwave simulation technology. Utilizing the impedance matching between multilayer metallic wire grids and multilayer absorbing material , we can improve maximum absorbing of the hybrid absorbing material, under the thichness of the multilayer absorbing material is invariant. And we can adjust the location of maximum absorbing with adjusting the radious and space of multilayer metallic wire grids. Some typical optimization simulation results are given. The results show that the designed maximum absorbing of the hybrid absorbing material with multilayer metallic wire grids can improve over 6 dB,And adjusted the location of maximum absorbing under keeping the good absorbing properties of hybrid material. The techniques can design different frequency absorbing material with design requirements.

  4. A Titanium Nitride Absorber for Controlling Optical Crosstalk in Horn-Coupled Aluminum LEKID Arrays for Millimeter Wavelengths

    CERN Document Server

    McCarrick, H; Jones, G; Johnson, B R; Ade, P A R; Bradford, K; Bryan, S; Cantor, R; Che, G; Day, P; Doyle, S; Leduc, H; Limon, M; Mauskopf, P; Miller, A; Mroczkowski, T; Tucker, C; Zmuidzinas, J

    2015-01-01

    We discuss the design and measured performance of a titanium nitride (TiN) mesh absorber we are developing for controlling optical crosstalk in horn-coupled lumped-element kinetic inductance detector arrays for millimeter-wavelengths. This absorber was added to the fused silica anti-reflection coating attached to previously-characterized, 20-element prototype arrays of LEKIDs fabricated from thin-film aluminum on silicon substrates. To test the TiN crosstalk absorber, we compared the measured response and noise properties of LEKID arrays with and without the TiN mesh. For this test, the LEKIDs were illuminated with an adjustable, incoherent electronic millimeter-wave source. Our measurements show that the optical crosstalk in the LEKID array with the TiN absorber is reduced by 66\\% on average, so the approach is effective and a viable candidate for future kilo-pixel arrays.

  5. A mechanical analysis of woodpecker drumming and its application to shock-absorbing systems

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Sang-Hee [Molecular Cell Biomechanics Laboratory, Department of Bioengineering, University of California, Berkeley, CA 94720 (United States); Park, Sungmin, E-mail: sang-hee.yoon@wyss.harvard.edu [Department of Mechanical Engineering, University of California, Berkeley, CA 94720 (United States)

    2011-03-15

    A woodpecker is known to drum the hard woody surface of a tree at a rate of 18 to 22 times per second with a deceleration of 1200 g, yet with no sign of blackout or brain damage. As a model in nature, a woodpecker is studied to find clues to develop a shock-absorbing system for micromachined devices. Its advanced shock-absorbing mechanism, which cannot be explained merely by allometric scaling, is analyzed in terms of endoskeletal structures. In this analysis, the head structures (beak, hyoid, spongy bone, and skull bone with cerebrospinal fluid) of the golden-fronted woodpecker, Melanerpes aurifrons, are explored with x-ray computed tomography images, and their shock-absorbing mechanism is analyzed with a mechanical vibration model and an empirical method. Based on these analyses, a new shock-absorbing system is designed to protect commercial micromachined devices from unwanted high-g and high-frequency mechanical excitations. The new shock-absorbing system consists of close-packed microglasses within two metal enclosures and a viscoelastic layer fastened by steel bolts, which are biologically inspired from a spongy bone contained within a skull bone encompassed with the hyoid of a woodpecker. In the experimental characterizations using a 60 mm smoothbore air-gun, this bio-inspired shock-absorbing system shows a failure rate of 0.7% for the commercial micromachined devices at 60 000 g, whereas a conventional hard-resin method yields a failure rate of 26.4%, thus verifying remarkable improvement in the g-force tolerance of the commercial micromachined devices.

  6. Photometric analysis of absorbable barbed suture for periareolar closure in mastopexy

    Institute of Scientific and Technical Information of China (English)

    Allen D Rosen; Alanna M Guzman; Teresa Hartman

    2016-01-01

    Aim:The primary author previously described his technique for periareolar closure in mastopexy using a pinwheel interlocking purse string with absorbable barbed suture and now reports the results of a retrospective photometric analysis comparing this technique with the same closure using Gortex® suture. This study is designed to compare the degree of areolar widening and safety proifle of using absorbable barbed sutures for periareolar closure versus permanent smooth suture. Methods:A retrospective chart review was conducted of all patients whose periareolar closures were performed using an interlocking purse-string technique over a 10-year period. Only patients undergoing circumvertical mastopexy were included. All had photometric evaluation and follow-up performed within 6-24 months. Results:In total, 20 patients (40 areolas), which were closed with absorbable barbed suture, were analyzed photometrically. In this suture group, areola size increased a mean of 4.9%from baseline, and no complications (0%) were observed. This compared favorably with previously reported complication rates using permanent sutures and with a series of cases presented herein in which permanent smooth suture was used for purse string closure. The degree to which absorbable barbed suture controls areolar spread was shown to be signiifcantly better than those where permanent smooth purse string techniques were employed. Conclusion:Circumvertical mastopexy closures using absorbable barbed suture was shown to be safe and effective and compared favorably to older techniques using permanent smooth suture for similar closures. This paper lends support to the safety of using absorbable barbed suture in circumareolar closures to limit areolar spread.

  7. Tuned dynamic absorber for split Stirling cryogenic cooler

    Science.gov (United States)

    Veprik, Alexander; Tuito, Avi

    2016-05-01

    Tuned dynamic absorbers (TDA) find use, in particular, for attenuating tonal vibration export produced by the moving components of cryogenic cooler. For the best performance, the resonant frequency of TDA needs to be essentially equal the driving frequency; accurate frequency match is favorably achieved by minimizing the cooler induced vibration by adjusting the driving frequency. For the best performance, the design of TDA needs to ensure minimum damping ratio; this is achievable by using planar flexural bearings having zero friction anchoring features. Accurate evaluation of effective mass, damping ratio and frequency is needed for TDA characterization during development and manufacturing. This data may be also important for the dynamic modelling. The authors are exploring the express method requiring no physical access to the proof mass of TDA. In this approach, the TDA is mounted upon the low frequency vibration mounted rod, the dynamic properties of TDA are then evaluated using the frequency response function - local accelerance - captured on the above rod using accelerometer, instrumented modal hammer and dual-channel signal analyzer. The authors are presenting the TDA design, outcomes of full-scale experimentation on dynamic properties evaluation and attained performance.

  8. Recent Advances in Conjugated Polymer-Based Microwave Absorbing Materials

    Directory of Open Access Journals (Sweden)

    Ying Wang

    2017-01-01

    Full Text Available Microwave absorbing materials (MAMs are paving the way for exciting applications in electromagnetic (EM pollution precaution and national defense security, as they offer an advanced alternative to conventional reflection principles to fundamentally eliminate the EM waves. Conjugated polymer (CP-based composites appear as a promising kind of MAM with the desirable features of low density and high performance. In this review, we introduce the theory of microwave absorption and summarize recent advances in the fabrication of CP-based MAMs, including rational design of the microstructure of pure conjugated polymers and tunable chemical integration with magnetic ferrites, magnetic metals, transition metal oxides, and carbon materials. The key point of enhancing microwave absorption in CP-based MAMs is to regulate their EM properties, improve matching of characteristic impedance, and create diversified loss mechanisms. The examples presented in this review will provide new insights into the design and preparation of CP-based composites that can satisfy the high demands of the oncoming generation of MAMs.

  9. An Omnidirectional Polarization Detector Based on a Metamaterial Absorber

    Science.gov (United States)

    Zhang, Binzhen; Zhang, Yong; Duan, Junping; Zhang, Wendong; Wang, Wanjun

    2016-01-01

    The theory, design, simulation, fabrication, and performance of an omnidirectional polarization detector (PD) with two resonances located in the X and Ka ranges based on a metamaterial absorber (MMA) are presented in this paper. The sandwich structure of PD is composed of 0.1 μm periodic “I” shaped patches on the metasurface, a dielectric of 200 μm FR-4 on the interlayer, and a 0.3 μm copper film on the substrate. PD absorptivity is first used to reflect and describe the polarization of the incident wave. The numerical results, derived from the standard full wave finite integration technology (FIT) of CST 2015, indicates that the designed PD shows polarization sensitivity at all incidence angles. The effects on absorptivity produced by the incidence angles, polarization angles, and materials are investigated. The amplitude of absorptivity change caused by polarization reaches 99.802%. A laser ablation process is adopted to prepare the designed PD on a FR-4 board coated with copper on the double plane with a thickness that was 1/93 and 1/48 of wavelength at a resonance frequency of 16.055 GHz and 30.9 GHz, respectively. The sample test results verify the designed PD excellent detectability on the polarization of the incident waves. The proposed PD, which greatly enriches the applications of metamaterials in bolometers, thermal images, stealth materials, microstructure measurements, and electromagnetic devices, is easy to mass produce and market because of its strong detectability, ultrathin thickness, effective cost, and convenient process. PMID:27455280

  10. Experimental investigation of a nanofluid absorber employed in a low-profile, concentrated solar thermal collector

    Science.gov (United States)

    Li, Qiyuan; Zheng, Cheng; Mesgari, Sara; Hewakuruppu, Yasitha L.; Hjerrild, Natasha; Crisostomo, Felipe; Morrison, Karl; Woffenden, Albert; Rosengarten, Gary; Scott, Jason A.; Taylor, Robert A.

    2015-12-01

    Recent studies [1-3] have demonstrated that nanotechnology, in the form of nanoparticles suspended in water and organic liquids, can be employed to enhance solar collection via direct volumetric absorbers. However, current nanofluid solar collector experimental studies are either relevant to low-temperature flat plate solar collectors (100 °C) indoor laboratory-scale concentrating solar collectors [1, 5]. Moreover, many of these studies involve in thermal properties of nanofluid (such as thermal conductivity) enhancement in solar collectors by using conventional selective coated steel/copper tube receivers [6], and no full-scale concentrating collector has been tested at outdoor condition by employing nanofluid absorber [2, 6]. Thus, there is a need of experimental researches to evaluate the exact performance of full-scale concentrating solar collector by employing nanofluids absorber at outdoor condition. As reported previously [7-9], a low profile (solar thermal concentrating collector was designed and analysed which can potentially supply thermal energy in the 100-250 °C range (an application currently met by gas and electricity). The present study focuses on the design and experimental investigation of a nanofluid absorber employed in this newly designed collector. The nanofluid absorber consists of glass tubes used to contain chemically functionalized multi-walled carbon nanotubes (MWCNTs) dispersed in DI water. MWCNTs (average diameter of 6-13 nm and average length of 2.5-20 μm) were functionalized by potassium persulfate as an oxidant. The nanofluids were prepared with a MCWNT concentration of 50 +/- 0.1 mg/L to form a balance between solar absorption depth and viscosity (e.g. pumping power). Moreover, experimentally comparison of the thermal efficiency between two receivers (a black chrome-coated copper tube versus a MWCNT nanofluid contained within a glass tubetube) is investigated. Thermal experimentation reveals that while the collector efficiency

  11. Light absorbing carbon emissions from commercial shipping

    Science.gov (United States)

    Lack, Daniel; Lerner, Brian; Granier, Claire; Baynard, Tahllee; Lovejoy, Edward; Massoli, Paola; Ravishankara, A. R.; Williams, Eric

    2008-07-01

    Extensive measurements of the emission of light absorbing carbon aerosol (LAC) from commercial shipping are presented. Vessel emissions were sampled using a photoacoustic spectrometer in the Gulf of Mexico region. The highest emitters (per unit fuel burnt) are tug boats, thus making significant contributions to local air quality in ports. Emission of LAC from cargo and non cargo vessels in this study appears to be independent of engine load. Shipping fuel consumption data (2001) was used to calculate a global LAC contribution of 133(+/-27) Ggyr-1, or ~1.7% of global LAC. This small fraction could have disproportionate effects on both air quality near port areas and climate in the Arctic if direct emissions of LAC occur in that region due to opening Arctic sea routes. The global contribution of this LAC burden was investigated using the MOZART model. Increases of 20-50 ng m-3 LAC (relative increases up to 40%) due to shipping occur in the tropical Atlantic, Indonesia, central America and the southern regions of South America and Africa.

  12. Mechatronic Design Automation

    DEFF Research Database (Denmark)

    Fan, Zhun

    successfully design analogue filters, vibration absorbers, micro-electro-mechanical systems, and vehicle suspension systems, all in an automatic or semi-automatic way. It also investigates the very important issue of co-designing plant-structures and dynamic controllers in automated design of Mechatronic...

  13. Perfect absorber metamaterial for real time detection and recognition of micro-poisons in aqueous solutions and atmosphere using millimeter wavelength spectroscopy

    Science.gov (United States)

    Abramovich, A.; Rotshild, D.; Ochana, M.; Rozban, D.

    2016-02-01

    Metamaterials are artificial materials not exist in the nature. They are also known as Left Handed Material (LHM) in which both the permeability and permittivity are negative. A perfect absorber metamaterial for millimeter wavelength can be artificially tailored and manufactured as two dimensional matrixes of metal shapes on a dielectric substrate. Those perfect absorbers metamaterial can be designed to be frequency selective with high Q property. In This study we present a new method that can provide real-time response by combining advanced spectroscopy methods in millimeter Wavelength (MMW) regime and perfect absorber metamaterial. This method is based on very inexpensive perfect absorber metamaterial, with a high Q factor. It was realized by printed metal shapes on FR4 substrate with ground plane on the bottom. The resonance frequency of the perfect absorber will be determined according to the geometrical metal shape dimensions and the dielectric constant of the substrate. The spectral measurements were carried out using high resolution coherence THz spectroscopy system. Due to the perfect absorber sensitivity and its high Q property, the perfect absorber metamaterial is very sensitive to environmental micro-poisons, which influence its resonance frequency. Using a high-resolution spectroscopy system it is possible to detect and quantify this influence. In this study we present very promising experimental results of Malathion detection using perfect absorber metamaterial. The manufacturing of such perfect absorber metamaterial was carried out using the well-known and very inexpensive PCB technology.

  14. Effects of Root-Growing Space on Its Absorbing Characteristics

    Institute of Scientific and Technical Information of China (English)

    SONG Hai-xing; LI Sheng-xiu

    2003-01-01

    Influences of root-growing space of maize upon root physiological characteristics, nutrient uptake and crop yields were studied under conditions with and without supply of water and N. Results showed that limitation of the root-growing space greatly affected root growth, decreased total root-absorbing area and TTC-reductive amounts. However, it obviously increased the root active-absorbing area, specific absorbing area (absorbing area per gram root weight) and specific active-absorbing area (actively absorbing area per gram root weight) in addition to promoting the TTC-reductive intensity. This clearly showed that plants were not passively tolerant to stress, but actively regulated their physiological metabolic processes, and strengthened their absorbing ability to increase water and nutrient uptake so that root injury by the environmental stress could be reduced. Supply of water and N stimulated root growth, increased root-absorbing area and activity, promoted nutrient uptake, and therefore increased crop yield and decreased the detrimental effects resulting from the limitation of roots-growing space.

  15. Preparation of Superabsorbent Polymers with Increased Saline Absorbency

    Institute of Scientific and Technical Information of China (English)

    LIU Song; JIN Yi-fen; ZHOU Xiang

    2002-01-01

    Superabsorbent having enhanced absorbency of 0.9%NaCl solution was synthesized on one basis of incorporating zwitterionic (sulfobetaine) monomer into the previous monomer mixture, which comprises ionic (AA) and nonionic monomers, and another basis of introducing inorganic salt B. As far as saline absorbency is concerned, introduction of inorganic salt B is more useful than the sulfobetaine monomer.

  16. A blast absorber test: measurement and model results

    NARCIS (Netherlands)

    Eerden, F.J.M. van der; Berg, F. van den; Hof, J. van 't; Arkel, E. van

    2006-01-01

    A blast absorber test was conducted at the Aberdeen Test Centre from 13 to 17 June 2005. The test was set up to determine the absorbing and shielding effect of a gravel pile, of 1.5 meters high and 15 by 15 meters wide, on blasts from large weapons: e.g. armor, artillery or demolition. The blast was

  17. 14 CFR 29.475 - Tires and shock absorbers.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Tires and shock absorbers. 29.475 Section... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Strength Requirements Ground Loads § 29.475 Tires and shock absorbers. Unless otherwise prescribed, for each specified landing condition, the tires must...

  18. 14 CFR 27.475 - Tires and shock absorbers.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Tires and shock absorbers. 27.475 Section... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements Ground Loads § 27.475 Tires and shock absorbers. Unless otherwise prescribed, for each specified landing condition, the tires must be assumed...

  19. Performance of Closely Spaced Point Absorbers with Constrained Floater Motion

    DEFF Research Database (Denmark)

    De Backer, G.; Vantorre, M.; Beels, C.;

    2009-01-01

    The performance of a wave energy converter array of twelve heaving point absorbers has been assessed numerically in a frequency domain model. Each point absorber is assumed to have its own linear power take-off. The impact of slamming, stroke and force restrictions on the power absorption...

  20. Photochromic And Thermochromic Pigments For Solar Absorbing-Reflecting Coatings

    Science.gov (United States)

    Novinson, Thomas

    1987-11-01

    Both photochromic and thermochromic compounds were synthesized and physical measurements were made to determine coefficients of relectance, absorbance and emission. The most interesting group of thermochromic compounds are related to silver tctraiodomercurate and the most interesting photochromic compounds are substituted benzoindolinopyrospirans. The synthesis and optical reflectance and absorbance properties of other classes of compounds are also reported.

  1. Experimental demonstration of trapping waves with terahertz metamaterial absorbers on flexible polyimide films

    Science.gov (United States)

    Wang, Wei; Liu, Jinsong; Wang, Kejia

    2016-02-01

    We present the design, numerical simulations and experimental measurements of an asymmetric cross terahertz metamaterial absorber (MPA) on ultra-flexible polyimide film. The perfect metamaterial absorber composed of two structured metallic layers separated with a polyimide film with a total thickness of functional layers much smaller than the operational wavelength. Two distinct absorption peaks are found at resonance frequencies of 0.439THz and 0.759 THz with resonance amplitude of near unity, which are in good agreement with the simulation results. The sample is also measured by a THz-TDS imaging system to illustrate the absorption characterization. The scanning images show that the sample could act as a perfect absorber at specific resonance frequencies while a perfect reflector at off resonance frequencies. To illustrate the physical mechanism behind these spectral responses, the distribution of the power loss and surface current are also presented. The result shows that the incident wave is trapped and absorbed by the polyimide dielectric layer at different vicinities of the proposed asymmetric cross MPA for the two absorption peaks. Furthermore, the index sensing performance of the structure is also investigated, and the calculated sensitivity is 90GHz/RIU for f1 mode and 154.7GHz/RIU for f2 mode, indicating that the higher frequency resonance absorption peak has better potential applications in sensing and detection. The ultra-flexible, low cost, high intensity dual band terahertz absorbers may pave the way for designing various terahertz functional devices, such as ultrasensitive terahertz sensors, spatial light modulators and filters.

  2. A wide-angle broadband absorber in graphene-based hyperbolic metamaterials

    Science.gov (United States)

    Ning, Renxia; Liu, Shaobin; Zhang, Haifeng; Bian, Borui; Kong, Xiangkun

    2014-11-01

    A wide-angle broadband absorber which is realized by periodic structures containing graphene-based hyperbolic metamaterials (GHMM) and isotropic medium is theoretically investigated. The GHMM is composed of monolayer graphene and conventional dielectric, which the refractive index can be tuned by the chemical potential, the thickness of dielectric and phenomenological scattering rates, respectively. A periodic structure of GHMM can obtain a broadband absorption which is shown to absorb roughly 70% (relative bandwidth is larger than 45%) of all available electromagnetic wave in absorption bandwidth at normal incident angle. Compared with some previous designs, our proposed structure has a relative bandwidth over a broad frequency range in mid-infrared. This kind periodic structures offer additional opportunities to design novel optoelectronic devices.

  3. Why muscle is an efficient shock absorber.

    Directory of Open Access Journals (Sweden)

    Michael A Ferenczi

    Full Text Available Skeletal muscles power body movement by converting free energy of ATP hydrolysis into mechanical work. During the landing phase of running or jumping some activated skeletal muscles are subjected to stretch. Upon stretch they absorb body energy quickly and effectively thus protecting joints and bones from impact damage. This is achieved because during lengthening, skeletal muscle bears higher force and has higher instantaneous stiffness than during isometric contraction, and yet consumes very little ATP. We wish to understand how the actomyosin molecules change their structure and interaction to implement these physiologically useful mechanical and thermodynamical properties. We monitored changes in the low angle x-ray diffraction pattern of rabbit skeletal muscle fibers during ramp stretch compared to those during isometric contraction at physiological temperature using synchrotron radiation. The intensities of the off-meridional layer lines and fine interference structure of the meridional M3 myosin x-ray reflection were resolved. Mechanical and structural data show that upon stretch the fraction of actin-bound myosin heads is higher than during isometric contraction. On the other hand, the intensities of the actin layer lines are lower than during isometric contraction. Taken together, these results suggest that during stretch, a significant fraction of actin-bound heads is bound non-stereo-specifically, i.e. they are disordered azimuthally although stiff axially. As the strong or stereo-specific myosin binding to actin is necessary for actin activation of the myosin ATPase, this finding explains the low metabolic cost of energy absorption by muscle during the landing phase of locomotion.

  4. Structure and Performance Analysis of Regenerative Electromagnetic Shock Absorber

    Directory of Open Access Journals (Sweden)

    Longxin Zhen

    2010-12-01

    Full Text Available This paper analyzed the structure and principle of a regenerative electromagnetic shock absorber in detail. The innovative shock absorber resembles linear generator in principle and can generate electric power through the relative reciprocating motion between coil assembly and permanent magnet assembly. At the same time, the damping can remove discomfort caused by road roughness. The regenerated electric power can be recovered through battery. Analysis of magnetic flux density of the permanent magnet array of the innovative shock absorber was performed using ANSYS software based on the structure parameters given in the paper,then the performance parameters of the shock absorber was determined . Analysis and calculation results prove the viability of this shock absorber.

  5. Magnetically rotational reactor for absorbing benzene emissions by ionic liquids

    Institute of Scientific and Technical Information of China (English)

    Yangyang; Jiang; Chen; Guo; Huizhou; Liu

    2007-01-01

    A magnetically rotational reactor (MRR) has been developed and used in absorbing benzene emissions. The MRR has a permanent magnet core and uses magnetic ionic liquid [bmim]FeCl4 as absorbent. Benzene emissions were carried by N2 into the MRR and were absorbed by the magnetic ionic liquid. The rotation of the permanent magnet core provided impetus for the agitation of the magnetic ionic liquid, enhancing mass transfer and making benzene better dispersed in the absorbent. 0.68 g benzene emissions could be absorbed by a gram of [bmim]FeCl4, 0.27 and 0.40 g/ghigher than that by [bmim]PF6 and [bmim]BF4, respectively. The absorption rate increased with increasing rotation rate of the permanent magnet.

  6. Absorber-evaporator unit for an absorption-refrigeration system

    Energy Technology Data Exchange (ETDEWEB)

    Hallatt, R.J.; Rorschach, R.L.

    1965-01-26

    This low temperature absorption-refrigeration system uses an absorber-evaporator. A conduit is connected between the upper portion of the absorber and the lower portion of the evaporator to conduct inert gas from the absorber to the evaporator. A second conduit connects the upper portion of the evaporator to the lower portion of the absorber and a blower in this conduit circulates the inert gas through the closed system. By placing the blower between the evaporator ad the absorber, the pressure in the evaporator is maintained at a minimum so that the working temperature is as low as possible. The medium to be cooled by the refrigerant is circulated through a heat exchanger located within the evaporator, whereby the latent heat of vaporization of the liquid refrigerant is employed to cool the outside medium. (2 claims)

  7. Thermally Induced Nonlinear Optical Absorption in Metamaterial Perfect Absorbers

    CERN Document Server

    Guddala, Sriram; Ramakrishna, S Anantha

    2015-01-01

    A metamaterial perfect absorber consisting of a tri-layer (Al/ZnS/Al) metal-dielectric-metal system with top aluminium nano-disks is fabricated by laser-interference lithography and lift-off processing. The metamaterial absorber had peak resonant absorbance at 1090 nm and showed nonlinear absorption for 600ps laser pulses at 1064 nm wavelength. A nonlinear saturation of reflectance was measured to be dependent on the average laser power incident and not the peak laser intensity. The nonlinear behaviour is shown to arise from the heating due to the absorbed radiation and photo-thermal changes in the dielectric properties of aluminium. The metamaterial absorber is seen to be damage resistant at large laser intensities of 25 MW/cm2.

  8. Dynamic Vibration Absorber with Negative Stiffness for Rotor System

    Directory of Open Access Journals (Sweden)

    Hongliang Yao

    2016-01-01

    Full Text Available To suppress the vibration of a rotor system, a vibration absorber combining negative stiffness with positive stiffness together is proposed in this paper. Firstly, the negative stiffness producing mechanism using ring type permanent magnets is presented and the characteristics of the negative stiffness are analyzed. Then, the structure of the absorber is proposed; the principles and nonlinear dynamic characteristics of the absorber-rotor system are studied numerically. Finally, experiments are carried out to verify the numerical conclusions. The results show that the proposed vibration absorber is effective to suppress the vibration of the rotor system, the nonlinearity of the negatives stiffness affects the vibration suppression effect little, and the negative stiffness can broaden the effective vibration control frequency range of the absorber.

  9. Multilayer metamaterial absorbers inspired by perfectly matched layers

    CERN Document Server

    Pastuszczak, Anna; Antosiewicz, Tomasz J; Kotynski, Rafal

    2014-01-01

    We derive periodic multilayer absorbers with effective uniaxial properties similar to perfectly matched layers (PML). This approximate representation of PML is based on the effective medium theory and we call it an effective medium PML (EM-PML). We compare the spatial reflection spectrum of the layered absorbers to that of a PML material and demonstrate that after neglecting gain and magnetic properties, the absorber remains functional. This opens a route to create electromagnetic absorbers for real and not only numerical applications and as an example we introduce a layered absorber for the wavelength of $8$~$\\mu$m made of SiO$_2$ and NaCl. We also show that similar cylindrical core-shell nanostructures derived from flat multilayers also exhibit very good absorptive and reflective properties despite the different geometry.

  10. Influence of Reaction Parameters on Water Absorbency of Starch Grafted Superabsorbents

    Institute of Scientific and Technical Information of China (English)

    LI Ming-da; ZHOU Yong-yuan

    2002-01-01

    Superabsorbents starch grafted sodium polyacrylate was synthesized by inverse suspension polymerization, using toluene as the continuous phase, potassium persulfate as the initiator. The effect of reaction parameters, such as starch pretreatment temperature, neutralization degree of monomer, reaction time and temperature,concentration of initiator, molar ratio of monomer and starch, on water absorbency of the starch grafted polymer was studied. The effects of the last two parameters were investigated by uniform design method,and the prediction equation was obtained.

  11. 980 nm High Power Semiconductor Laser Stacked Arrays with Non-absorbing Window

    Institute of Scientific and Technical Information of China (English)

    Xin GAO; Baoxue BO; Yi QU; Jing ZHANG; Hui LI

    2007-01-01

    980 nm InGaAs/GaAs separate confinement heterostructure (SCH) strained quantum well (QW) laser with non-absorbing facets was fabricated by using thermal treatment. Microchannel coolers with a five-layer thin oxygen-free copper plate structure were designed and fabricated through thermal bonding in hydrogen ambient.The highest CW (continuous wave) output power of 200 W for 5-bar arrays packaged by microchannel coolers was presented.

  12. A Simple Laser-Based Device for Simultaneous Microbial Culture and Absorbance Measurement

    CERN Document Server

    Abrevaya, X C; Areso, O; Mauas, P J D

    2012-01-01

    In this work we present a device specifically designed to study microbial growth with several applications related to environmental microbiology and other areas of research as astrobiology. The Automated Measuring and Cultivation device (AMC-d) enables semi-continuous absorbance measurements directly during cultivation. It can measure simultaneously up to 16 samples. Growth curves using low and fast growing microorganism were plotted, including: Escherichia coli, and Haloferax volcanii, an halophilic archaeon.

  13. Literature search on Light Water Reactor (LWR) fuel and absorber rod fabrication, 1960--1976

    Energy Technology Data Exchange (ETDEWEB)

    Sample, C R [comp.

    1977-02-01

    A literature search was conducted to provide information supporting the design of a conceptual Light Water Reactor (LWR) Fuel Fabrication plant. Emphasis was placed on fuel processing and pin bundle fabrication, effects of fuel impurities and microstructure on performance and densification, quality assurance, absorber and poison rod fabrication, and fuel pin welding. All data have been taken from publicly available documents, journals, and books. This work was sponsored by the Finishing Processes-Mixed Oxide (MOX) Fuel Fabrication Studies program at HEDL.

  14. The Effect of the Configuration of the Absorber on the Performance of Flat Plate Thermal Collector

    OpenAIRE

    Yan, Moyu; Qu, Ming; Peng, Steve

    2016-01-01

    In this study, a numerical thermal analysis for a new designed flat plate thermal collector was conducted through modeling. The new flat plate thermal collector has ellipse shaped tubes inside a wavy shaped absorber, which is made of stainless steel. For the comparison, the conventional flat plate thermal collector with circular copper tubes served as a base case was also modeled. Hottel-Whillier equations were utilized to formulate thermal networks for both models developed in Engineering Eq...

  15. Electromagnetic resonances of wavelength-selective solar absorbers with film-coupled fishnet gratings

    Science.gov (United States)

    Matsuno, Yuki; Sakurai, Atsushi

    2017-02-01

    The purpose of this study is to clarify the optical characteristics of a Tungsten-SiO2-based film-coupled metamaterial with a fishnet-shaped grating, and we aim to show that this structure could potentially be used as a solar selective absorber for a solar thermophotovoltaic system. The proposed film-coupled metamaterial absorber combined with a fishnet-shaped grating shows significant enhancement in its absorption in the visible spectral region compared with a flat Tungsten surface, and it keeps its spectral emission low in the infrared region, thereby reducing radiative heat loss. The underlying mechanisms of the proposed absorber are discussed through a 3D full-wave electromagnetic simulation, the results of which are compared with that of theoretical equations. Furthermore, its spectral absorption under oblique incident light at the transverse magnetic and transverse electric waves is scrutinized. The underlying absorption mechanisms and relations between each optical resonance are discussed in this paper and will prove to be fundamental not only in the design of solar selective absorbers but also in other wavelength-selective thermal radiation controlling devices.

  16. Experimental studies on active control of a dynamic system via a time-delayed absorber

    Science.gov (United States)

    Xu, Jian; Sun, Yixia

    2015-04-01

    The traditional passive absorber is fully effective within a narrow and certain frequency band. To solve this problem, a time-delayed acceleration feedback is introduced to convert a passive absorber into an active one. Both the inherent and the intentional time delays are included. The former mainly comes from signal acquiring and processing, computing, and applying the actuation force, and its value is fixed. The latter is introduced in the controller, and its value is actively adjustable. Firstly, the mechanical model is established and the frequency response equations are obtained. The regions of stability are delineated in the plane of control parameters. Secondly, the design scheme of control para- meters is performed to help select the values of the feedback gain and time delay. Thirdly, the experimental studies are conducted. Effects of both negative and positive feedback control are investigated. Experimental results show that the proper choices of control parameters may broaden the effective frequency band of vibration absorption. Moreover, the time-delayed absorber greatly suppresses the resonant response of the primary system when the passive absorber totally fails. The experimental results are in good agreement with the theoretical predictions and numerical simulations.

  17. Enhancing Localized Evaporation through Separated Light Absorbing Centers and Scattering Centers.

    Science.gov (United States)

    Zhao, Dengwu; Duan, Haoze; Yu, Shengtao; Zhang, Yao; He, Jiaqing; Quan, Xiaojun; Tao, Peng; Shang, Wen; Wu, Jianbo; Song, Chengyi; Deng, Tao

    2015-11-26

    This report investigates the enhancement of localized evaporation via separated light absorbing particles (plasmonic absorbers) and scattering particles (polystyrene nanoparticles). Evaporation has been considered as one of the most important phase-change processes in modern industries. To improve the efficiency of evaporation, one of the most feasible methods is to localize heat at the top water layer rather than heating the bulk water. In this work, the mixture of purely light absorptive plasmonic nanostructures such as gold nanoparticles and purely scattering particles (polystyrene nanoparticles) are employed to confine the incident light at the top of the solution and convert light to heat. Different concentrations of both the light absorbing centers and the light scattering centers were evaluated and the evaporation performance can be largely enhanced with the balance between absorbing centers and scattering centers. The findings in this study not only provide a new way to improve evaporation efficiency in plasmonic particle-based solution, but also shed lights on the design of new solar-driven localized evaporation systems.

  18. Graphene based tunable fractal Hilbert curve array broadband radar absorbing screen for radar cross section reduction

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xianjun, E-mail: xianjun.huang@manchester.ac.uk [School of Electrical and Electronic Engineering, University of Manchester, Manchester M13 9PL (United Kingdom); College of Electronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China); Hu, Zhirun [School of Electrical and Electronic Engineering, University of Manchester, Manchester M13 9PL (United Kingdom); Liu, Peiguo [College of Electronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

    2014-11-15

    This paper proposes a new type of graphene based tunable radar absorbing screen. The absorbing screen consists of Hilbert curve metal strip array and chemical vapour deposition (CVD) graphene sheet. The graphene based screen is not only tunable when the chemical potential of the graphene changes, but also has broadband effective absorption. The absorption bandwidth is from 8.9GHz to 18.1GHz, ie., relative bandwidth of more than 68%, at chemical potential of 0eV, which is significantly wider than that if the graphene sheet had not been employed. As the chemical potential varies from 0 to 0.4eV, the central frequency of the screen can be tuned from 13.5GHz to 19.0GHz. In the proposed structure, Hilbert curve metal strip array was designed to provide multiple narrow band resonances, whereas the graphene sheet directly underneath the metal strip array provides tunability and averagely required surface resistance so to significantly extend the screen operation bandwidth by providing broadband impedance matching and absorption. In addition, the thickness of the screen has been optimized to achieve nearly the minimum thickness limitation for a nonmagnetic absorber. The working principle of this absorbing screen is studied in details, and performance under various incident angles is presented. This work extends applications of graphene into tunable microwave radar cross section (RCS) reduction applications.

  19. Mathematical Model of a Lithium-Bromide/Water Absorption Refrigeration System Equipped with an Adiabatic Absorber

    Directory of Open Access Journals (Sweden)

    Salem M. Osta-Omar

    2016-11-01

    Full Text Available The objective of this paper is to develop a mathematical model for thermodynamic analysis of an absorption refrigeration system equipped with an adiabatic absorber using a lithium-bromide/water (LiBr/water pair as the working fluid. The working temperature of the generator, adiabatic absorber, condenser, evaporator, the cooling capacity of the system, and the ratio of the solution mass flow rate at the circulation pump to that at the solution pump are used as input data. The model evaluates the thermodynamic properties of all state points, the heat transfer in each component, the various mass flow rates, and the coefficient of performance (COP of the cycle. The results are used to investigate the effect of key parameters on the overall performance of the system. For instance, increasing the generator temperatures and decreasing the adiabatic absorber temperatures can increase the COP of the cycle. The results of this mathematical model can be used for designing and sizing new LiBr/water absorption refrigeration systems equipped with an adiabatic absorber or for optimizing existing aforementioned systems.

  20. Space Evaporator Absorber Radiator (SEAR) for Thermal Storage on Manned Spacecraft

    Science.gov (United States)

    Izenson, Michael G.; Chen, Weibo; Chepko, Ariane; Bue, Grant; Quinn, Gregory

    2014-01-01

    Future manned exploration spacecraft will need to operate in challenging thermal environments. State-of the- art technology for active thermal control relies on sublimating water ice and venting the vapor overboard in very hot environments. This approach can lead to large loss of water and a significant mass penalty for the spacecraft. This paper describes an innovative thermal control system that uses a Space Evaporator Absorber Radiator (SEAR) to control spacecraft temperatures in highly variable environments without venting water. SEAR uses heat pumping and energy storage by LiCl/water absorption to enable effective cooling during hot periods and regeneration during cool periods. The LiCl absorber technology has the potential to absorb over 800 kJ per kg of system mass, compared to phase change heat sink systems that typically achieve approx. 50 kJ/kg. The optimal system is based on a trade-off between the mass of water saved and extra power needed to regenerate the LiCl absorber. This paper describes analysis models and the predicted performance and optimize the size of the SEAR system, estimated size and mass of key components, and power requirements for regeneration. We also present a concept design for an ISS test package to demonstrate operation of a subscale system in zero gravity.

  1. 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.

  2. Microwave absorbance properties of zirconium–manganese substituted cobalt nanoferrite as electromagnetic (EM) wave absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Kishwar, E-mail: kknano@hotmail.com; Rehman, Sarish

    2014-02-01

    Highlights: • Good candidates for EM materials with low reflectivity. • Good candidates for broad bandwidth at microwave frequency. • Microwave absorbing bandwidth was modulated simply by manipulating the Zr–Mn. • Higher the Zr–Mn content, the higher absorption rates for the electromagnetic radiation. • The predicted reflection loss shows that this can be used for thin ferrite absorber. - Abstract: Nanocrystalline Zr–Mn (x) substituted Co ferrite having chemical formula CoFe{sub 2−2x}Zr{sub x}Mn{sub x}O{sub 4} (x = 0.1–0.4) was prepared by co-precipitation technique. Combining properties such as structural, electrical, magnetic and reflection loss characteristics. Crystal structure and surface morphology of the calcined samples were characterized by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). By using two point probe homemade resistivity apparatus to find resistivity of the sample. Electromagnetic (EM) properties are measured through RF impedance/materials analyzer over 1 MHz–3 GHz. The room-temperature dielectric measurements show dispersion behavior with increasing frequency from 100 Hz to 3 MHz. Magnetic properties confirmed relatively strong dependence of saturation magnetization on Zr–Mn composition. Curie temperature is also found to decrease linearly with addition of Zr–Mn. Furthermore, comprehensive analysis of microwave reflection loss (RL) is carried out as a function of substitution, frequency, and thickness. Composition accompanying maximum microwave absorption is suggested.

  3. SCOR 1000: an economic and innovative conceptual design PWR

    Energy Technology Data Exchange (ETDEWEB)

    Gautier, G.M.; Chenaud, M.S. [CEA Cadarache (DEN/DER/SESI), 13 - Saint Paul lez Durance (France). Dept. d' Etudes des Reacteurs; Tourniaire, B. [CEA Grenoble (DEN/DTN/SE2T/LPTM), 38 (France)

    2007-07-01

    Within the framework of innovative reactors studies, the Cea proposes the SCOR design (Simple COmpact Reactor) based on most of the advantages of innovative reactors. All main components are integrated in the vessel: the pressurizer, the canned pumps, the control rod mechanics of the driving system (CMD), and the dedicated heat exchangers of the passive heat removal system. The only steam generator is located above the vessel instead of the upper head. This design is featured by its compactness and by a large suppression or simplification of auxiliary systems. The first design with a 600 MWe shows its competitiveness with regard to the large loop-type PWR. To reduce the cost investment by the law sized effect, we examine the possibility of increasing the power of the reactor, while keeping the safety advantages of the medium sized SCOR. The electrical power of the new design is 1000 MWe. SCOR-1000 operates at much lower primary circuit pressure than standard PWRs (93 bars instead of the usual 155 bars), and the power density is lower (80 MW/m3 instead of 100 for the present PWRs). The reactivity is controlled by the CMD and by the burnable poison, without soluble boron. With the same safety advantages of the medium-sized SCOR, the cost reduction of the investment and of cost production could reach 18% with regard to the loop-type PWR. (authors)

  4. Simulation Process Analysis of Rubber Shock Absorber for Machine Tool

    Directory of Open Access Journals (Sweden)

    Chai Rong Xia

    2016-01-01

    Full Text Available The simulation on rubber shock absorber of machine tool was studied. The simple material model of rubber was obtained by through the finite element analysis software ABAQUS. The compression speed and the hardness of rubber material were considered to obtain the deformation law of rubber shock absorber. The location of fatigue were confirmed from the simulation results. The results shown that the fatigue position is distributed in the corner of shock absorber. The degree of deformation is increased with increasing of compress speed, and the hardness of rubber material is proportional to deformation.

  5. Towards Perfectly Absorbing Boundary Conditions for Euler Equations

    Science.gov (United States)

    Hayder, M. Ehtesham; Hu, Fang Q.; Hussaini, M. Yousuff

    1997-01-01

    In this paper, we examine the effectiveness of absorbing layers as non-reflecting computational boundaries for the Euler equations. The absorbing-layer equations are simply obtained by splitting the governing equations in the coordinate directions and introducing absorption coefficients in each split equation. This methodology is similar to that used by Berenger for the numerical solutions of Maxwell's equations. Specifically, we apply this methodology to three physical problems shock-vortex interactions, a plane free shear flow and an axisymmetric jet- with emphasis on acoustic wave propagation. Our numerical results indicate that the use of absorbing layers effectively minimizes numerical reflection in all three problems considered.

  6. A review of development and implementation of an active nonlinear vibration absorber

    Energy Technology Data Exchange (ETDEWEB)

    Oueini, S.S.; Nayfeh, A.H. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Engineering Science and Mechanics; Pratt, J.R. [Manufacturing Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899-001 (United States)

    1999-10-01

    We present an account of an implementation of an active nonlinear vibration absorber that we have developed. The control technique exploits the saturation phenomenon that is known to occur in quadratically-coupled multi-degree-of-freedom systems subjected to primary excitation and possessing a two-to-one internal resonance. The technique is based on introducing an absorber and coupling it with the structure through a sensor and an actuator, where the feedback and control signals are quadratic. First, we consider the case of controlling the vibrations of a single-degree-of-freedom system. We develop the equations governing the response of the closed-loop system and use the method of multiple scales to obtain an approximate solution. We investigate the performance of the control strategy by studying its steady-state and transient characteristics. Additionally, we compare the performance of the quadratic absorber with that of a linear absorber. Then, we present theoretical and experimental results that demonstrate the versatility of the technique. We design an electronic circuit to emulate the absorber and use a variety of sensors and actuators to implement the active control strategy. First, we use a motor and a potentiometer to control the vibration of a rigid beam. We develop a plant model that includes Coulomb friction and demonstrate that the closed-loop system exhibits the saturation phenomenon. Second, we extend the strategy to multi-degree-of-freedom systems. We use PZT ceramics and strain gages to suppress vibrations of flexible steel beams when subjected to single- and simultaneous two-mode excitations. Third, we employ Terfenol-D, a nonlinear actuator, and accelerometers to control the vibrations of flexible beams. In all instances, the technique is successful in reducing the response amplitude of the structures. (orig.)

  7. Realizing thin electromagnetic absorbers for wide incidence angles from commercially available planar circuit materials

    Energy Technology Data Exchange (ETDEWEB)

    Glover, Brian B [Los Alamos National Laboratory; Whites, Kieth W [SDSMT; Radway, Matthew J [CU-BOULDER

    2009-01-01

    In this study, recent work on engineering R-card surface resistivity with printed metallic patterns is extended to the design of thin electromagnetic absorbers. Thin electromagnetic absorbers for wide incidence angles and both polarizations have recently been computationally verified by Luukkonen et al.. These absorbers are analytically modeled high-impedance surfaces with capacitive arrays of square patches implemented with relatively high dielectric constant and high loss substrate. However, the advantages provided by the accurate analytical model are largely negated by the need to obtain high dielectric constant material with accurately engineered loss. Fig. I(c) illustrates full-wave computational results for an absorber without vias engineered as proposed by Luukkonen et al.. Unique values for the dielectric loss are required for different center frequencies. Parameters for the capacitive grid are D=5.0 mm and w=O.l mm for a center frequency of 3.36 GHz. The relative permittivity and thickness is 9.20(1-j0.234) and 1=3.048 mm. Consider a center frequency of5.81 GHz and again 1=3.048 mm, the required parameters for the capacitive grid are D=2.0 mm and w=0.2 mm where the required relative permittivity is now 9.20(1-j0.371) Admittedly, engineered dielectrics are themselves a historically interesting and fruitful research area which benefits today from advances in monolithic fabrication using direct-write of dielectrics with nanometer scale inclusions. However, our objective in the present study is to realize the advantages of the absorber proposed by Luukkonen et al. without resort to engineered lossy dielectrics. Specifically we are restricted to commercially available planer circuit materials without use of in-house direct-write technology or materials engineering capability. The materials considered here are TMM 10 laminate with (35 {mu}lm copper cladding with a complex permittivity 9.20-j0.0022) and Ohmegaply resistor conductor material (maximum 250 {Omega

  8. A promising lightweight multicomponent microwave absorber based on doped barium hexaferrite/calcium titanate/multiwalled carbon nanotubes

    Science.gov (United States)

    Afghahi, Seyyed Salman Seyyed; Jafarian, Mojtaba; Atassi, Yomen

    2016-07-01

    We present the design of a microwave absorber in the X band based on ternary nanocomposite of doped barium hexaferrite (Ba-M)/calcium titanate (CTO)/multiwall carbon nanotubes (MWCNTs) in epoxy matrix. The hydrothermal method has been used to synthesize Ba-M and CTO nanopowder. The phase identification has been investigated using XRD patterns. Scanning electron microscope, transmission electron microscope, vibrating sample magnetometer, and vector network analyzer are used to analyze the morphology of the different components and the magnetic, electromagnetic, and microwave absorption properties of the final composite absorbers, respectively. As far as we know, the design of this type of multicomponent microwave absorber has not been investigated before. The results reveal that the combination of these three components with their different loss mechanisms has a synergistic effect that enhances the attenuation properties of the final composite. The absorber of only 2.5-mm thickness and 35 wt% of loading ratio exhibits a minimum reflection loss of -43 dB at 10.2 GHz with a bandwidth of 3.6 GHz, while the corresponding absorber based on pure (Ba-M) shows a minimum reflection loss of -34 dB at 9.8 GHz with a bandwidth of 0.256 GHz and a thickness of 4 mm.

  9. Fabrication of hard-coated optical absorbers with microstructured surfaces using etched ion tracks: Toward broadband ultra-low reflectance

    Energy Technology Data Exchange (ETDEWEB)

    Amemiya, Kuniaki, E-mail: k.amemiya@aist.go.jp [National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8563 (Japan); Koshikawa, Hiroshi; Yamaki, Tetsuya; Maekawa, Yasunari [Quantum Beam Science Center, Japan Atomic Energy Agency (JAEA), 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan); Shitomi, Hiroshi; Numata, Takayuki; Kinoshita, Kenichi; Tanabe, Minoru; Fukuda, Daiji [National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8563 (Japan)

    2015-08-01

    Highlights: • A hard-coated optical absorber with microstructured surface was fabricated. • Etched ion tracks coated with diamond-like carbon were used. • The reflectance was below 2% for wavelengths in the 400–1400 nm range. • Fabricated optical absorber exhibited temporal durability and mechanical stability. • Further improvement of the design and process will yield reflectance of ∼0.1%. - Abstract: Broadband low reflectance materials have various applications in the field of optical energy management; however, materials with ultra-low reflectance (below 0.1%) have been considered as mechanically delicate. We have developed a novel hard-surface optical absorber with microstructured, diamond-like carbon coated ion tracks on CR-39 plastic substrate. The spectral reflectance of the first prototype was below 2% for wavelengths ranging from 400 nm to 1400 nm; moreover, the optical absorber had mechanically hard surface and exhibited temporal durability. Choosing the appropriate design of the surface structure and coating layer is likely to reduce the reflectance to the order of 0.1%. This technique yields easy-to-handle broadband ultra-low reflectance absorbers.

  10. Millimeter Wave Absorber for Secure Identification

    CERN Document Server

    Skirlo, Scott A; Nasr, Magued; Heimbeck, Martin S; Joannopoulos, John D; Soljacic, Marin; Everitt, Henry O; Domash, Lawrence

    2016-01-01

    We demonstrate thin, flexible, metamaterial films with a strong, narrowband, polarization- and angle-insensitive absorption designed for wavelengths near one millimeter. These structures, fabricated by photolithography on a commercially available, copper-backed polyimide substrate, are nearly indistinguishable to the unaided human eye but can be easily observed by imaging at the resonance frequency of the film. We demonstrate that these patterns can be used to mark or barcode objects for secure identification with a terahertz imaging system.

  11. Wheeler-Feynman Absorbers on the Light Horizon

    CERN Document Server

    Lear, C W

    2016-01-01

    Early Wheeler-Feynman absorber theories invoke both retarded and advanced electromagnetic waves for photon emission and absorption in order to remove problems involving lack of radiative damping during electron acceleration. Subsequent inquiries have suggested that only certain cosmologies would allow such a retarded-advanced wave mechanism to exist. These include quasi-steady state cosmologies and exclude flat, expanding Friedman-type cosmologies. Key to the exclusion process is a diminishing density of future absorbers in an ever-expanding universe. Such absorbers would be expected to be real electromagnetically interacting particles. However future virtual absorber sites, if they exist, would not be so diminished. Such sites would be plentiful on the future light horizon, receding from the source at the speed of light. The present treatment proposes that virtual absorption sites are present at every point in spacetime, and are characterized by the Fresnel-Kirchhoff diffraction integral. On the future light...

  12. Liquid absorbent solutions for separating nitrogen from natural gas

    Science.gov (United States)

    Friesen, Dwayne T.; Babcock, Walter C.; Edlund, David J.; Lyon, David K.; Miller, Warren K.

    2000-01-01

    Nitrogen-absorbing and -desorbing compositions, novel ligands and transition metal complexes, and methods of using the same, which are useful for the selective separation of nitrogen from other gases, especially natural gas.

  13. Radio-absorbing properties of nickel-containing schungite powder

    Science.gov (United States)

    Lyn'kov, L. M.; Borbot'ko, T. V.; Krishtopova, E. A.

    2009-05-01

    A nickel-containing shungite powder has been synthesized by means of chemical reduction from aqueous solutions. The chemical composition and radio-absorbing properties of this powder have been studied.

  14. Power Absorption by Closely Spaced Point Absorbers in Constrained Conditions

    DEFF Research Database (Denmark)

    De Backer, G.; Vantorre, M.; Beels, C.;

    2010-01-01

    The performance of an array of closely spaced point absorbers is numerically assessed in a frequency domain model Each point absorber is restricted to the heave mode and is assumed to have its own linear power take-off (PTO) system Unidirectional irregular incident waves are considered, represent......The performance of an array of closely spaced point absorbers is numerically assessed in a frequency domain model Each point absorber is restricted to the heave mode and is assumed to have its own linear power take-off (PTO) system Unidirectional irregular incident waves are considered......, representing the wave climate at Westhinder on the Belgian Continental Shelf The impact of slamming, stroke and force restrictions on the power absorption is evaluated and optimal PTO parameters are determined For multiple bodies optimal control parameters (CP) are not only dependent on the incoming waves...

  15. Experimental investigation of damping force of twin tube shock absorber

    Directory of Open Access Journals (Sweden)

    Sandip K. Kadu

    2014-09-01

    Full Text Available A shock absorber is a mechanical device to damp shock impulse and convert kinetic energy into thermal energy. The damping effect of shock absorber depends on damping force and damping force is affected by various process parameters. In this analysis three process parameters damping diameter(A, number of holes(B and suspension velocity(C were considered and their effect on damping force of shock absorber was studied and accordingly suitable orthogonal array was selected by taguchi method. Experiment conducted on servo hydraulic testing machine and after conducting experiments damping force was measured and with the help of S/N ratio, ANOVA, Regression analysis optimum parameter values can be obtained and confirmation experiments was carried out. Twin tube shock absorber was used to carry out experimentation.

  16. Evaluation of electromagnetic absorbing capacity of materials in foundry industry

    Directory of Open Access Journals (Sweden)

    D. Nowak

    2010-01-01

    Full Text Available In the paper, a research on determining the standing wave ratio as a measure of electromagnetic absorbing capacity of moulding materials is presented. Preliminary tests performed using a microwave strip line showed that high-silica, chromite and magnesite moulding sands are characterised by low absorbing capacity of microwaves. It was demonstrated that microwave absorbing capacity is significantly affected by chemical compounds included in the examined substrates. It was found that use of a microwave strip line permits precise determining characteristic microwave absorbing capacities of various moulding materials and thus their suitability for microwave drying/hardening of moulds and cores or for other foundry processes. Such a microwave drier can be applied for identifying mass components and for determining e.g. base granularity by means of precisely determined reflection ratios |Γ| and positions of minimum signal values.

  17. Angular solar absorptance of absorbers used in solar thermal collectors.

    Science.gov (United States)

    Tesfamichael, T; Wäckelgård, E

    1999-07-01

    The optical characterization of solar absorbers for thermal solar collectors is usually performed by measurement of the spectral reflectance at near-normal angle of incidence and calculation of the solar absorptance from the measured reflectance. The solar absorptance is, however, a function of the angle of incidence of the light impinging on the absorber. The total reflectance of two types of commercial solar-selective absorbers, nickel-pigmented anodized aluminum, and sputtered nickel nickel oxide coated aluminum are measured at angles of incidence from 5 to 80 in the wavelength range 300-2500 nm by use of an integrating sphere. From these measurements the angular integrated solar absorptance is determined. Experimental data are compared with theoretical calculations, and it is found that optical thin-film interference effects can explain the significant difference in solar absorptance at higher angles for the two types of absorbers.

  18. [Decoloring and spectral properties analysis of innoxious ultraviolet absorbents].

    Science.gov (United States)

    Fang, Yi-Wen; Ni, Wen-Xiu; Huang, Chong; Xue, Liang; Yu, Lin

    2006-07-01

    The ultraviolet absorbent extracted from mango leaves, was discolored by some decoloring agent. Then the spectral properties of the discolored ultraviolet absorbents were analyzed. The discolored method of ultraviolet absorbent was studied by comparing one with the others. The results showed that the discoloring effect was satisfactory by using active carbon, H2O2, citric acid, and oxalic acid as decoloring agent. Specially, when oxalic acid was used as decoloring agent, the color of the production was slight, the rate of production was high, and the absorption effect of ultraviolet ray was well. When the concentration of the ultraviolet absorbent solution is 0.5% (w/w), the ultraviolet ray transmission was smaller than 0.3% in 200-370 nm, and it increased slightly from 370 nm. There was a maximum value at 400 nm, approaching 12%.

  19. Distribution of Doppler Redshifts of Associated Absorbers of SDSS Quasars

    Indian Academy of Sciences (India)

    Cai-Juan Pan; Zhi-Fu Chen

    2013-12-01

    Doppler redshifts of a sample of Mg II associated absorbers of SDSS DR7 quasars are analysed. We find that there might be three Gaussian components in the distribution of the Doppler redshift. The first Gaussian component, with the peak being located at Dopp = -0.0074, probably arises from absorbers with outflow histories observed in the direction close to jets of quasars. The second Gaussian component, with the peak being located at Dopp = -0.0017, possibly arises from absorbers with outflow histories observed in the direction far away from jets of quasars. Whereas, the third Gaussian component, with the peak being located at Dopp = -0.0004, might arise from the random motion of absorbers with respect to quasars.

  20. Integrated microcalorimeters using Ir TES and Sn mushroom absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Galeazzi, M. [Department of Physics, University of Miami, 1320 Campo Sano Dr., Coral Gables, FL 33146 (United States)]. E-mail: Galeazzi@physics.miami.edu; Bogorin, D. [Department of Physics, University of Miami, 1320 Campo Sano Dr., Coral Gables, FL 33146 (United States); Chen, C. [Department of Physics, University of Miami, 1320 Campo Sano Dr., Coral Gables, FL 33146 (United States)

    2006-04-15

    University of Miami has recently started a program to fabricate fully integrated microcalorimeter arrays using iridium thin films as Transition Edge Sensors (TES) and tin mushroom absorbers. We present our preliminary results in both areas.

  1. Catalog of strong MgII absorbers (Lawther+, 2012)

    DEFF Research Database (Denmark)

    Lawther, D.; Paarup, Troels; Schmidt, Morten L.

    2012-01-01

    of our paper. A subset of the absorbers have been visually inspected - see the MAN_OK flag in the catalog. The number of sightlines searched, tabulated by absorber redshift, i.e. g(z), is available as an ASCII table (for S/N>8 and S/N>15). All analysis in our paper is based on the SNR>8 coverage......Here we present a catalog of strong (rest equivalent width Wr> intervening Mg II absorbers in the SDSS Data Release 7 quasar catalog (2010AJ....139.2360S, Cat. VII/260). The intervening absorbers were found by a semi-automatic algorithm written in IDL - for details of the algorithm see section 2...

  2. 21 CFR 878.4830 - Absorbable surgical gut suture.

    Science.gov (United States)

    2010-04-01

    ... (CONTINUED) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4830 Absorbable...) or the submucosal fibrous tissue of sheep (ovine) intestine, and is intended for use in soft...

  3. New Insight into the Angle Insensitivity of Ultrathin Planar Optical Absorbers for Broadband Solar Energy Harvesting.

    Science.gov (United States)

    Liu, Dong; Yu, Haitong; Duan, Yuanyuan; Li, Qiang; Xuan, Yimin

    2016-09-01

    Two challenging problems still remain for optical absorbers consisting of an ultrathin planar semiconductor film on top of an opaque metallic substrate. One is the angle-insensitive mechanism and the other is the system design needed for broadband solar energy harvesting. Here, first we theoretically demonstrates that the high refractive index, instead of the ultrathin feature as reported in previous studies, is the physical origin of the angle insensitivity for ultrathin planar optical absorbers. They exhibit omnidirectional resonance for TE polarization due to the high complex refractive index difference between the semiconductor and the air, while for TM polarization the angle insensitivity persists up to an incident angle related to the semiconductor refractive index. These findings were validated by fabricating and characterizing an 18 nm Ge/Ag absorber sample (representative of small band gap semiconductors for photovoltaic applications) and a 22 nm hematite/Ag sample (representative of large band gap semiconductors for photoelectrochemical applications). Then, we took advantage of angle insensitivity and designed a spectrum splitting configuration for broadband solar energy harvesting. The cascaded solar cell and unassisted solar water splitting systems have photovoltaic and photoelectrochemical cells that are also spectrum splitters, so an external spectrum splitting element is not needed.

  4. New Insight into the Angle Insensitivity of Ultrathin Planar Optical Absorbers for Broadband Solar Energy Harvesting

    Science.gov (United States)

    Liu, Dong; Yu, Haitong; Duan, Yuanyuan; Li, Qiang; Xuan, Yimin

    2016-09-01

    Two challenging problems still remain for optical absorbers consisting of an ultrathin planar semiconductor film on top of an opaque metallic substrate. One is the angle-insensitive mechanism and the other is the system design needed for broadband solar energy harvesting. Here, first we theoretically demonstrates that the high refractive index, instead of the ultrathin feature as reported in previous studies, is the physical origin of the angle insensitivity for ultrathin planar optical absorbers. They exhibit omnidirectional resonance for TE polarization due to the high complex refractive index difference between the semiconductor and the air, while for TM polarization the angle insensitivity persists up to an incident angle related to the semiconductor refractive index. These findings were validated by fabricating and characterizing an 18 nm Ge/Ag absorber sample (representative of small band gap semiconductors for photovoltaic applications) and a 22 nm hematite/Ag sample (representative of large band gap semiconductors for photoelectrochemical applications). Then, we took advantage of angle insensitivity and designed a spectrum splitting configuration for broadband solar energy harvesting. The cascaded solar cell and unassisted solar water splitting systems have photovoltaic and photoelectrochemical cells that are also spectrum splitters, so an external spectrum splitting element is not needed.

  5. Fabrication of metasurface-based infrared absorber structures using direct laser write lithography

    Science.gov (United States)

    Fanyaeu, Ihar; Mizeikis, Vygantas

    2016-03-01

    We report fabrication and optical properties of ultra-thin polarization-invariant electromagnetic absorber metasurface for infra-red spectral. The absorber structure, which uses three-dimensional architecture is based on single-turn metallic helices arranged into a periodic square lattice on a metallic substrate, is expected to exhibit total resonant absorption due to balanced coupling between resonances of the helices. The structure was designed using numerical simulations aiming to tune the total absorption resonance to infra-red wavelength range by appropriately downscaling the unit cell of the structure, and taking into account dielectric dispersion and losses of the metal. The designed structures were subsequently fabricated using femtosecond direct laser write technique in a dielectric photoresist, and subsequent metallisation by gold sputtering. In accordance with the expectations, the structure was found to exhibit resonant absorption centred near the wavelength of 6 - 9 µm, with peak absorption in excess of 82%. The absorber metasurface may be applied in various areas of science and technology, such as harvesting infra-red radiation in thermal detectors and energy converters.

  6. Numerical Approach of the Influence of Geometric Properties on the Absorbing in Photonic Crystal

    Directory of Open Access Journals (Sweden)

    A. Merabti

    2016-10-01

    Full Text Available In the proposed study, an investigation has been carried out in order to find a material efficient structure, capable of harnessing maximum solar spectrum. A material efficient structure designed using a one dimensional photonic crystal (1D PC for amorphous silicon. Silicon material is used as it leads to environmental friendly design. The principal objective of this study is to maximize the photon absorption, keeping reflection to a minimum. The influence of geometric parameters on the absorption is studied by using the Finite element method (FEM. The results show that the absorption is affected by the geometry parameters. The optimum parameters of the proposed structure are period (a  480 nm, a filling factor (ff  50 % and depth (d  150 nm. The increase of absorption in the lower region where the wavelengths are around 480 nm, is explained by the reduction of the effective index resulting from the structure of the absorbent layer. For wavelengths between 480 nm and 600 nm, the absorption is directly related to existing Fabry-Perot modes within the absorbent layer. Creating additional absorption peaks at wavelengths above about 600 nm weakly absorbed normally comes from the coupling of the incident light with slow Bloch modes of PC located above the light line.

  7. New Insight into the Angle Insensitivity of Ultrathin Planar Optical Absorbers for Broadband Solar Energy Harvesting

    Science.gov (United States)

    Liu, Dong; Yu, Haitong; Duan, Yuanyuan; Li, Qiang; Xuan, Yimin

    2016-01-01

    Two challenging problems still remain for optical absorbers consisting of an ultrathin planar semiconductor film on top of an opaque metallic substrate. One is the angle-insensitive mechanism and the other is the system design needed for broadband solar energy harvesting. Here, first we theoretically demonstrates that the high refractive index, instead of the ultrathin feature as reported in previous studies, is the physical origin of the angle insensitivity for ultrathin planar optical absorbers. They exhibit omnidirectional resonance for TE polarization due to the high complex refractive index difference between the semiconductor and the air, while for TM polarization the angle insensitivity persists up to an incident angle related to the semiconductor refractive index. These findings were validated by fabricating and characterizing an 18 nm Ge/Ag absorber sample (representative of small band gap semiconductors for photovoltaic applications) and a 22 nm hematite/Ag sample (representative of large band gap semiconductors for photoelectrochemical applications). Then, we took advantage of angle insensitivity and designed a spectrum splitting configuration for broadband solar energy harvesting. The cascaded solar cell and unassisted solar water splitting systems have photovoltaic and photoelectrochemical cells that are also spectrum splitters, so an external spectrum splitting element is not needed. PMID:27582317

  8. Calirimeter/absorber optimization for a RHIC dimuon experiment

    Energy Technology Data Exchange (ETDEWEB)

    Aronson, S.H.; Murtagh, M.J.; Starks, M. [Brookhaven National Lab., Upton, NY (United States); Liu, X.T.; Petitt, G.A.; Zhang, Z. [Georgia State Univ., Atlanta (United States); Ewell, L.A.; Hill, J.C.; Wohn, F.K. [Iowa State Univ., Ames (United States); Costales, J.B.; Namboodiri, M.N., Sangster, T.C.; Thomas, J.H. [Lawrence Livermore National Lab., CA (United States); Gavron, A.; Waters, L. [Los Alamos National Lab., NM (United States); Kehoe, W.L.; Steadman, S.G. [Massachusetts Institute of Technology, Cambridge (United States); Awes, T.C.; Obenshain, F.E.; Saini, S.; Young, G.R. [Oak Ridge National Lab., TN (United States); Chang, J.; Fung, S.Y.; Kang, J.H. [Univ. of California, Riverside, CA (United States); Kreke, J.; He, Xiaochun, Sorensen, S.P. [Univ. of Tennessee, Knoxville (United States); Cornell, E.C.; Maguire, C.F. [Vanderbilt Univ., Nashville, TN (United States)

    1991-12-31

    The RD-10 R&D effort on calorimeter/absorber optimization for a RHIC experiment had an extended run in 1991 using the A2 test beam at the AGS. Measurements were made of the leakage of particles behind various model hadron calorimeters. Behavior of the calorimeter/absorber as a muon-identifier was studied. First comparisons of results from test measurements to calculated results using the GHEISHA code were made

  9. On the fluid-loaded thin-panel absorbers

    Institute of Scientific and Technical Information of China (English)

    TONG Xiaopeng; BAI Guofeng; LIU Ke; TIAN Jing

    2009-01-01

    The sound absorption of fluid-loaded thin-panel absorbers was investigated. A general theory and an approximate theory are given. Parameters of potential energy kinetic energy, and the fluid-loading factor are proposed. This has made the absorption mechanism clearer, and the computation simpler than before. The absorption coefficients and impedances of thin-panel absorbers were tested with a hydro-acoustical tube. The experimental results agreed well with the theoretical results.

  10. Phase transition analogies in a laser with saturable absorber

    Energy Technology Data Exchange (ETDEWEB)

    Dembinski, S.T.; Kossakowski, A. (Uniwersytet Mikolaja Kopernika, Torun (Poland). Instytut Fizyki)

    1976-01-01

    The possible threshold behavior of a four-level laser in the presence of a saturable absorber is examined. In the parameter space of the absorber, regions where the threshold behavior resemble first or second order phase transitions are found. The analysis is based on the semi-classical approximation and makes use of some concepts taken from Thom's theory of catastrophes.

  11. Propionate absorbed from the colon acts as gluconeogenic substrate in a strict carnivore, the domestic cat (Felis catus)

    DEFF Research Database (Denmark)

    Verbrugghe, A; Hesta, M; Daminet, S

    2012-01-01

    In six normal-weight and six obese cats, the metabolic effect of propionate absorbed from the colon was assessed. Two colonic infusions were tested in a crossover design with intervals of 4 weeks. The test solution contained 4 mmol sodium propionate per kg ideal body weight in a 0.2% NaCl solution...

  12. A full assembly and bakeout have just been successfully completed on the conical ALICE Absorber beam vacuum chambers

    CERN Multimedia

    Maximilien Brice

    2006-01-01

    Pictures 01 & 02 : a good example of cooperation: Several of the 70 people involved in the project pose in front of the ALICE Absorber containing the beam pipe. Six CERN departments and six sub-contracting companies have participated in the design, production and testing of this vacuum chamber.

  13. High-flux solar absorber concept for central receiver power plants

    Science.gov (United States)

    Pomeroy, B. D.; Roberts, J. M.; Narayanan, T. V.

    1981-02-01

    For cylindrical receivers with a capacity of about 400 MW/t, an aim-at-the belt focusing strategy can produce average fluxes the order of 0.5 MW/sq m with peaks as high as 2 MW/sq m. An absorber concept is described which uses liquid sodium coolant and a three-header configuration to efficiently capture this solar power. The mechanical design of this absorber is discussed and thermal performance estimates are presented showing the solar-capture efficiency over a range of solar intensities. The sodium-flow characteristics and some potential flow-control problems are also described. A thermal-stress analysis is presented which shows that a limiting factor on the flux capability may be tube-wall creep/fatigue failure and not the heat-transfer capability of sodium.

  14. Optimization of the active absorber scheme for the protection of the Dispersion Suppressor

    CERN Document Server

    Magistris, M; Assmann, R; Bracco, C; Brugger, M; Cerutti, F; Ferrari, A; Redaelli, S; Vlachoudis, V

    2009-01-01

    There are two main types of cold elements in IR7: quadrupole and dipole magnets (MQ and MB). According to predictions, these objects are to lose their superconducting properties if the spurious power densities reach about 1 and 5 mW/cm3, respectively. In order to protect these fragile components, 5 active absorbers (TCLA) were designed and a systematic study was launched to maximize the shielding efficiency of the absorber system for different configurations (locations and orientations). The TCLA's are identical to the secondary collimators (TCS), the only difference is found in the material of the jaw, which, initially, was set integrally to Cu (instead of C) and later included a small W insertion. This report summarizes the survey of cold element protection through TCLA insertion optimization.

  15. CMOS-compatible fabrication of metamaterial-based absorbers for the mid-IR spectral range

    Science.gov (United States)

    Karimi Shahmarvandi, Ehsan; Ghaderi, Mohammadamir; Wolffenbuttel, Reinoud F.

    2016-10-01

    A CMOS-compatible approach is presented for the fabrication of a wideband mid-IR metamaterial-based absorber on top of a Si3N4 membrane, which contains poly-Si thermopiles. The application is in IR microspectrometers that are intended for implementation in portable microsystem for use in absorption spectroscopy. Although Au is the conventional material of choice, we demonstrate by simulation that near-perfect absorption can be achieved over a wider band when using the more CMOS-compatible Al. The absorber design is based on Al disk resonators and an Al backplane, which are separated by a SiO2 layer. The fabrication process involves the deposition of Al and SiO2 layers on top of a Si3N4 membrane, lithography and a lift-off process for patterning of the top Al layer.

  16. ECG movement artefacts can be greatly reduced with the aid of a movement absorbing device

    DEFF Research Database (Denmark)

    Harrison, Adrian Paul; Wandall, Kirsten; Thorball, Jørgen

    2007-01-01

    Accurate ECG signal analysis can be confounded by electric lead, and/or electrode movements varying in origin from, for example, hiccups, tremor or patient restlessness. ECG signals recorded using either a conventional electrode holder or with the aid of an electrode holder capable of absorbing...... movement artefacts, were measured on a healthy human subject. Results show a greatly improved stability of the ECG signal recorded using an electrode holder capable of absorbing movement artefacts during periods of lead disturbance, and highlight the movement artefacts that develop when the recording lead...... of a conventional ECG electrode holder is tugged or pulled during theperiod of monitoring. It is concluded that the new design of ECG electrode holder will not only enable clearer signal recordings for clinical assessment, but will reduce the ECG artefacts associated with the transportation of patients, and may...

  17. Investigations on laser transmission welding of absorber-free thermoplastics

    Science.gov (United States)

    Mamuschkin, Viktor; Olowinsky, Alexander; Britten, Simon W.; Engelmann, Christoph

    2014-03-01

    Within the plastic industry laser transmission welding ranks among the most important joining techniques and opens up new application areas continuously. So far, a big disadvantage of the process was the fact that the joining partners need different optical properties. Since thermoplastics are transparent for the radiation of conventional beam sources (800- 1100 nm) the absorbance of one of the joining partners has to be enhanced by adding an infrared absorber (IR-absorber). Until recently, welding of absorber-free parts has not been possible. New diode lasers provide a broad variety of wavelengths which allows exploiting intrinsic absorption bands of thermoplastics. The use of a proper wavelength in combination with special optics enables laser welding of two optically identical polymer parts without absorbers which can be utilized in a large number of applications primarily in the medical and food industry, where the use of absorbers usually entails costly and time-consuming authorization processes. In this paper some aspects of the process are considered as the influence of the focal position, which is crucial when both joining partners have equal optical properties. After a theoretical consideration, an evaluation is carried out based on welding trials with polycarbonate (PC). Further aspects such as gap bridging capability and the influence of thickness of the upper joining partner are investigated as well.

  18. Wideband-Switchable Metamaterial Absorber Using Injected Liquid Metal

    Science.gov (United States)

    Kim, Hyung Ki; Lee, Dongju; Lim, Sungjoon

    2016-01-01

    Metamaterial absorbers can provide good solutions for radar-cross-section (RCS) reduction. In spite of their attractive features of thinness, lightness, and low cost, resonant metamaterial absorbers have a drawback of narrow bandwidth. For practical radar applications, wideband absorbers are necessary. In this paper, we propose a wideband-switchable metamaterial absorber using liquid metal. In order to reduce RCS both for X-band and C-band, the switchable Jerusalem cross (JC) resonator is introduced. The JC resonator consists of slotted circular rings, chip resistors, and microfluidic channels. The JC resonator is etched on a flexible printed circuit board (FPCB), and the microfluidic channels are laser-etched on a polydimethylsiloxane (PDMS) material. The proposed absorber can switch the absorption frequency band by injecting a liquid metal alloy into the channels. The performance of the absorber was demonstrated through full-wave simulation and through measurements employing prototypes. The experimental results showed absorption ratios of over 90% from 7.43 GHz to 14.34 GHz, and from 5.62 GHz to 7.3 GHz, with empty channels and liquid metal-filled channels, respectively. Therefore, the absorption band was successfully switched between the C-band (4–8 GHz) and the X-band (8–12 GHz) by injecting liquid metal eutectic gallium indium alloy (EGaIn) into the channels. PMID:27546310

  19. Contribution of recoil atoms to irradiation damage in absorber materials

    Science.gov (United States)

    Simeone, D.; Hablot, O.; Micalet, V.; Bellon, P.; Serruys, Y.

    1997-08-01

    Absorbing materials are used to control the reactivity of nuclear reactors by taking advantage of nuclear reactions (e.g., 10B(n,α) 7Li) where neutrons are absorbed. During such reactions, energetic recoils are produced. As a result, radiation damage in absorbing materials originates both from these nuclear reactions and from elastic collisions between neutrons and atoms. This damage eventually leads to a partial destruction of the materials, and this is the main limitation on their lifetime in nuclear reactors. Using a formalism developed to calculate displacements per atoms (dpa) in a multi atomic target, we have calculated damages in terms of displacements per atom in a (n,α) absorbing material taking into account geometrical effects of 10 boron self shielding and transmutation reactions induced by neutrons inside the absorber. Radiation damage is calculated for boron carbide and hafnium diboride ceramics in a Pressurized Water Reactor environment. It is shown that recoils produced by nuclear reactions account for the main part of the radiation damage created in these ceramics. Damages are calculated as a function of the distance from the center of an absorber pellet. Due to the self-shielding effect, these damage curves exhibit sharp maxima, the position of which changes in time.

  20. RESEARCH ON MODELING AND CHARACTERISTICS OF THE SPINDLE DYNAMIC COUPLING ABSORBERING SYSTEM OF A SUPER-PRECISION SURFACE GRINDING MACHINE

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The bearing is described by constrain matrix, and the spindle system of a NC surface grinding machine is simplified as elastic-coupling beam, then modal synthesis method is used to establish the dynamic model of beam.Moreover, the response of the end of rotor is analyzed, and the natural frequency, principle mode and other dynamic characteristics of the coupling system are studied, the law of bearing stiffness to coupling frequency and amplitude of rotor is also found.Finally, according to the actual condition, a dynamic absorber is designed.The simulation and experimental results show that the amplitude of spindle can be declined effectively when the dynamic absorber is attached.