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Sample records for deployable reflector ldr

  1. Large Deployable Reflector (LDR) Requirements for Space Station Accommodations

    Science.gov (United States)

    Crowe, D. A.; Clayton, M. J.; Runge, F. C.

    1985-01-01

    Top level requirements for assembly and integration of the Large Deployable Reflector (LDR) Observatory at the Space Station are examined. Concepts are currently under study for LDR which will provide a sequel to the Infrared Astronomy Satellite and the Space Infrared Telescope Facility. LDR will provide a spectacular capability over a very broad spectral range. The Space Station will provide an essential facility for the initial assembly and check out of LDR, as well as a necessary base for refurbishment, repair and modification. By providing a manned platform, the Space Station will remove the time constraint on assembly associated with use of the Shuttle alone. Personnel safety during necessary EVA is enhanced by the presence of the manned facility.

  2. Large deployable reflectors for telecom and earth observation applications

    Science.gov (United States)

    Scialino, L.; Ihle, A.; Migliorelli, M.; Gatti, N.; Datashvili, L.; van `t Klooster, K.; Santiago Prowald, J.

    2013-12-01

    Large deployable antennas are one of the key components for advanced missions in the fields of telecom and earth observation. In the recent past, missions have taken on board large deployable reflector (LDR) up to 22 m of diameter and several missions have already planned embarking large reflectors, such as the 12 m of INMARSAT XL or BIOMASS. At the moment, no European LDR providers are available and the market is dominated by Northrop-Grumman and Harris. Consequently, the development of European large reflector technology is considered a key step to maintain commercial and strategic competitiveness (ESA Large Reflector Antenna Working Group Final Report, TEC-EEA/2010.595/CM, 2010). In this scenario, the ESA General Study Project RESTEO (REflector Synergy between Telecom and Earth Observation), starting from the identification of future missions needs, has identified the most promising reflector concepts based on European heritage/technology, able to cover the largest range of potential future missions for both telecom and earth observation. This paper summarizes the activities and findings of the RESTEO Study.

  3. Surface Optimization Techniques for Deployable Reflectors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Under this and several other programs, CTD has developed TEMBOREG deployable solid-surface reflectors (TEMBOREG Reflectors) to provide future NASA and Air Force...

  4. Deployment simulation of a deployable reflector for earth science application

    Science.gov (United States)

    Wang, Xiaokai; Fang, Houfei; Cai, Bei; Ma, Xiaofei

    2015-10-01

    A novel mission concept namely NEXRAD-In-Space (NIS) has been developed for monitoring hurricanes, cyclones and other severe storms from a geostationary orbit. It requires a space deployable 35-meter diameter Ka-band (35 GHz) reflector. NIS can measure hurricane precipitation intensity, dynamics and its life cycle. These information is necessary for predicting the track, intensity, rain rate and hurricane-induced floods. To meet the requirements of the radar system, a Membrane Shell Reflector Segment (MSRS) reflector technology has been developed and several technologies have been evaluated. However, the deployment analysis of this large size and high-precision reflector has not been investigated. For a pre-studies, a scaled tetrahedral truss reflector with spring driving deployment system has been made and tested, deployment dynamics analysis of this scaled reflector has been performed using ADAMS to understand its deployment dynamic behaviors. Eliminating the redundant constraints in the reflector system with a large number of moving parts is a challenging issue. A primitive joint and flexible struts were introduced to the analytical model and they can effectively eliminate over constraints of the model. By using a high-speed camera and a force transducer, a deployment experiment of a single-bay tetrahedral module has been conducted. With the tested results, an optimization process has been performed by using the parameter optimization module of ADAMS to obtain the parameters of the analytical model. These parameters were incorporated to the analytical model of the whole reflector. It is observed from the analysis results that the deployment process of the reflector with a fixed boundary experiences three stages. These stages are rapid deployment stage, slow deployment stage and impact stage. The insight of the force peak distributions of the reflector can help the optimization design of the structure.

  5. Advanced deployable reflectors for communications satellites

    Science.gov (United States)

    Lowe, Elvin; Josephs, Michael; Hedgepeth, John

    1993-02-01

    This paper discusses a concept for a deployable mesh reflector for large spacecraft antennas and the processes used in design, fabrication and testing. A set of overall reflector requirements such as stowed volume, deployed diameter and RF loss derived from system specifications are presented. The development of design and analysis tools to allow parametric studies such as facet size, number of ribs and number of rib segments is discussed. CATIA (a commercially available three-dimensional design and analysis tool) is used to perform kinematic analyses as well as to establish the database to be used by the several groups participating in the development is examined. Results of trade studies performed to reduce cost with minimum risk to product delivery are included. A thirty foot reflector has been built and tested.

  6. Detection of extrasolar planets by the large deployable reflector

    Science.gov (United States)

    Hollenbach, D. J.; Takahashi, T.

    1984-01-01

    The best wavelength for observing Jupiter-size planetary companions to stars other than the Sun is one at which a planet's thermal emission is strongest; typically this would occur in the far-infrared region. It is assumed that the orbiting infrared telescope used is diffraction-limited so that the resolution of the planet from the central star is accomplished in the wings of the star's Airy pattern. Proxima Centauri, Barnard's Star, Wolf 359, and Epsilon Eridani are just a few of the many nearest main-sequence stars that could be studied with the large deployable relfector (LDR). The detectability of a planet improves for warmer planets and less luminous stars; therefore, planets around white dwarfs and those young planets which have sufficient internal gravitational energy release so as to cause a significant increase in their temperatures are considered. If white dwarfs are as old as they are usually assumed to be (5-10 billion yr), then only the nearest white dwarf (Sirius B) is within the range of LDR. The Ursa Major cluster and Perseu cluster are within LDR's detection range mainly because of their proximity and young age, respectively.

  7. Form-finding methods for deployable mesh reflector antennas

    Institute of Scientific and Technical Information of China (English)

    Li Tuanjie; Jiang Jie; Deng Hanqing; Lin Zhanchao; Wang Zuowei

    2013-01-01

    Deployable high-frequency mesh reflector antennas for future communications and obser-vations are required to obtain high gain and high directivity. In order to support these new missions, reflectors with high surface accuracy are widely required. The form-finding analysis of deployable mesh reflector antennas becomes more vital which aims to determine the initial surface profile formed by the equilibrium prestress distribution in cables to satisfy the surface accuracy requirement. In this paper, two form-finding methods for mesh reflector antennas, both of which include two steps, are pro-posed. The first step is to investigate the prestress design only for the cable net structure as the circum-ferential nodes connected to the supporting truss are assumed fixed. The second step is to optimize the prestress distribution of the boundary cables connected directly to the supporting truss considering the elastic deformation of the antenna structure. Some numerical examples are carried out and the simu-lation results demonstrate the proposed form-finding methods can warrant the deformed antenna reflector surface matches the one by design and the cable tension forces fall in a specified range.

  8. Solar Thermal Vacuum Test of Deployable Astromesh Reflector

    Science.gov (United States)

    Stegman, Matthew D.

    2009-01-01

    On September 10, 2008, a 36-hour Solar Thermal Vacuum Test of a 5m deployable mesh reflector was completed in JPL's 25' Space Simulator by the Advanced Deployable Structures Group at JPL. The testing was performed under NASA's Innovative Partnership Program (IPP) as a risk reduction effort for two JPL Decadal Survey Missions: DESDynI and SMAP. The 5.0 m aperture Astromesh reflector was provided by Northrop Grumman Aerospace Systems (NGAS) Astro Aerospace, our IPP industry partner. The testing utilized a state-of-the-art photogrammetry system to measure deformation of the reflector under LN2 cold soak, 0.25 Earth sun, 0.5 sun and 1.0 sun. An intricate network of thermocouples (approximately 200 in total) was used to determine the localized temperature across the mesh as well as on the perimeter truss of the reflector. Half of the reflector was in a fixed shadow to maximize thermal gradients. A mobility system was built for remotely actuating the cryo-vacuum capable photogrammetry camera around the circumference of the Solar Simulator. Photogrammetric resolution of 0.025 mm RMS (0.001") was achieved over the entire 5 meter aperture for each test case. The data will be used for thermo-elastic model correlation and validation, which will benefit the planned Earth Science Missions.

  9. A bionic approach to mathematical modeling the fold geometry of deployable reflector antennas on satellites

    Science.gov (United States)

    Feng, C. M.; Liu, T. S.

    2014-10-01

    Inspired from biology, this study presents a method for designing the fold geometry of deployable reflectors. Since the space available inside rockets for transporting satellites with reflector antennas is typically cylindrical in shape, and its cross-sectional area is considerably smaller than the reflector antenna after deployment, the cross-sectional area of the folded reflector must be smaller than the available rocket interior space. Membrane reflectors in aerospace are a type of lightweight structure that can be packaged compactly. To design membrane reflectors from the perspective of deployment processes, bionic applications from morphological changes of plants are investigated. Creating biologically inspired reflectors, this paper deals with fold geometry of reflectors, which imitate flower buds. This study uses mathematical formulation to describe geometric profiles of flower buds. Based on the formulation, new designs for deployable membrane reflectors derived from bionics are proposed. Adjusting parameters in the formulation of these designs leads to decreases in reflector area before deployment.

  10. LDR structural technology activities at JPL

    Science.gov (United States)

    Wada, Ben

    1988-01-01

    The status of the Large Deployable Reflector (LDR) technology requirements and the availability of that technology in the next few years are summarized. The research efforts at JPL related to these technology needs are also discussed. LDR requires that a large and relatively stiff truss-type backup structure have a surface accurate to 100 microns in space (initial position with thermal distortions) and the dynamic characteristics predictable and/or measurable by on-orbit system identification for micron level motion. This motion may result from the excitation of the lower modes or from wave-type motions. It is also assumed that the LDR structure can be ground tested to validate its ability to meet mission requirements. No program manager will commit a structural design based solely on analysis, unless the analysis is backed by a validation test program.

  11. Thermal distortion analysis of a deployable parabolic reflector

    Science.gov (United States)

    Bruck, L. R.; Honeycutt, G. H.

    1973-01-01

    A thermal distortion analysis of the ATS-6 Satellite parabolic reflector was performed using NASTRAN level 15.1. The same NASTRAN finite element method was used to conduct a one g static load analysis and a dynamic analysis of the reflector. In addition, a parametric study was made to determine which parameters had the greatest effect on the thermal distortions. The method used to model the construction of the reflector is described and the results of the analyses are presented.

  12. Thermomechanical analysis of large deployable space reflector antenna

    Directory of Open Access Journals (Sweden)

    Ponomarev Viktor S.

    2015-01-01

    Full Text Available In this article results of large reflector thermal condition forecast using modern numerical simulation methods are presented. The results of thermal analysis are complemented with stress-strain analysis results of the whole structure under thermal loads.

  13. On-ground electrical performance verification strategies for large deployable reflector antennas

    DEFF Research Database (Denmark)

    Pivnenko, Sergey; Kim, Oleksiy S.; Breinbjerg, Olav;

    2012-01-01

    In this paper, possible verification strategies for large deployable reflector antennas are reviewed and analysed. One of the approaches considered to be the most feasible and promising is based on measurements of the feed characteristics, such as pattern and gain, and then calculation of the ove...

  14. Mechanical behaviour of tape springs used in the deployment of reflectors around a solar panel

    Science.gov (United States)

    Dewalque, Florence; Collette, Jean-Paul; Brüls, Olivier

    2016-06-01

    In order to increase the production of power on small satellites, solar panels are commonly deployed and, in some cases, reflectors are added to improve the concentration factor on solar cells. In this work, reflectors are deployed by the means of compliant mechanisms known as tape springs. Their attractive characteristics are, among others, their passive behaviour, their self-locking capacity, their elastic deformations and their robustness. However, their mechanical behaviour is highly nonlinear and requires thorough analyses in order to develop predictive numerical models. It is shown here through parametric studies that the nonlinear behaviour of a tape spring is mainly governed by its geometry. Thus, for each specific application, its dimensions can be determined in order to minimise two critical features: the maximum stress affecting the structure and the maximum motion amplitude during deployment. In this paper, an optimisation procedure is proposed to meet these requirements.

  15. Surface accuracy analysis and mathematical modeling of deployable large aperture elastic antenna reflectors

    Science.gov (United States)

    Coleman, Michael J.

    One class of deployable large aperture antenna consists of thin light-weight parabolic reflectors. A reflector of this type is a deployable structure that consists of an inflatable elastic membrane that is supported about its perimeter by a set of elastic tendons and is subjected to a constant hydrostatic pressure. A design may not hold the parabolic shape to within a desired tolerance due to an elastic deformation of the surface, particularly near the rim. We can compute the equilibrium configuration of the reflector system using an optimization-based solution procedure that calculates the total system energy and determines a configuration of minimum energy. Analysis of the equilibrium configuration reveals the behavior of the reflector shape under various loading conditions. The pressure, film strain energy, tendon strain energy, and gravitational energy are all considered in this analysis. The surface accuracy of the antenna reflector is measured by an RMS calculation while the reflector phase error component of the efficiency is determined by computing the power density at boresight. Our error computation methods are tailored for the faceted surface of our model and they are more accurate for this particular problem than the commonly applied Ruze Equation. Previous analytical work on parabolic antennas focused on axisymmetric geometries and loads. Symmetric equilibria are not assumed in our analysis. In addition, this dissertation contains two principle original findings: (1) the typical supporting tendon system tends to flatten a parabolic reflector near its edge. We find that surface accuracy can be significantly improved by fixing the edge of the inflated reflector to a rigid structure; (2) for large membranes assembled from flat sheets of thin material, we demonstrate that the surface accuracy of the resulting inflated membrane reflector can be improved by altering the cutting pattern of the flat components. Our findings demonstrate that the proper choice

  16. Packaging, deployment, and panel design concepts for a truss-stiffened 7-panel precision deployable reflector with feed boom

    Science.gov (United States)

    Heard, Walter L., Jr.; Collins, Timothy J.; Dyess, James W.; Kenner, Scott; Bush, Harold G.

    1993-01-01

    A concept is presented for achieving a remotely deployable truss-stiffened reflector consisting of seven integrated sandwich panels that form the reflective surface, and an integrated feed boom. The concept has potential for meeting aperture size and surface precision requirements for some high-frequency microwave remote sensing applications. The packaged reflector/feed boom configuration is a self-contained unit that can be conveniently attached to a spacecraft bus. The package has a cylindrical envelope compatible with typical launch vehicle shrouds. Dynamic behavior of a deployed configuration having a 216-inch focal length and consisting of 80-inch-diameter, two-inch-thick panels is examined through finite-element analysis. Results show that the feed boom and spacecraft bus can have a large impact on the fundamental frequency of the deployed configuration. Two candidate rib-stiffened sandwich panel configurations for this application are described, and analytical results for panel mass and stiffness are presented. Results show that the addition of only a few rib stiffeners, if sufficiently deep, can efficiently improve sandwich panel stiffness.

  17. Dynamic analysis of the deployment for mesh reflector deployable antennas with the cable-net structure

    Science.gov (United States)

    Zhang, Yiqun; Li, Na; Yang, Guigeng; Ru, Wenrui

    2017-02-01

    This paper presents a dynamic analysis approach for the composite structure of a deployable truss and cable-net system. An Elastic Catenary Element is adopted to model the slack/tensioned cables. Then, from the energy standpoint, the kinetic energy, elasticity-potential energy and geopotential energy of the cable-net structure and deployable truss are derived. Thus, the flexible multi-body dynamic model of the deployable antenna is built based on the Lagrange equation. The effect of the cable-net tension on the antenna truss is discussed and compared with previous publications and a dynamic deployment analysis is performed. Both the simulation and experimental results verify the validity of the method presented.

  18. Simulation of Locking Space Truss Deployments for a Large Deployable Sparse Aperture Reflector

    Science.gov (United States)

    2015-03-01

    constructed and then simplified in SolidWorks . The solid models were imported in COMSOL where the connecting bodies, joints, and boundary conditions... Solidworks to show how the trusses are stowed and deployed. This geometry is simpli- fied in the following section so that the simulations can focus...order to create a reasonable representation of the geometry. All modeling was done in Solidworks , which was chosen because of its availability and

  19. Feedback shape control for deployable mesh reflectors using gain scheduling method

    Science.gov (United States)

    Xie, Yangmin; Shi, Hang; Alleyne, Andrew; Yang, Bingen

    2016-04-01

    This paper presents a theoretical study on the dynamic shape control problem of deployable mesh reflectors (DMRs) via feedback approaches. The reflector structure is simplified from a nonlinear model to be quasi-static with respect to temperature variations but dynamic with respect to mechanical vibrations. The orbital cycle is segmented into multiple temperature zones, and an H∞ robust state feedback controller is designed for each zone to guarantee the local stability of the system under the model uncertainty caused by thermal effects and to reject external force disturbances. At the same time, gain scheduling control method is adopted to compensate thermal distortions and to ensure smooth transition response when switching among the local robust controllers. A DMR model is considered in the case study to show the effectiveness of the control approach. The structural vibrations caused by external force disturbances can be sufficiently suppressed in a much shorter time. The closed loop response of the DMR structure shows that much higher surface accuracy is obtained during the orbiting mission compared to the open-loop configuration, and transient focal length and transient de-focus of the reflector are well controlled within the satisfactory bounds, demonstrating the numerical feasibility of the proposed method to solve the dynamic shape control problem of DMRs.

  20. Design of a Shape Memory Alloy deployment hinge for reflector facets

    Science.gov (United States)

    Anders, W. S.; Rogers, C. A.

    1991-01-01

    A design concept for a Shape Memory Alloy (SMA) actuated hinge mechanism for deploying segmented facet-type reflector surfaces on antenna truss structures is presented. The mechanism uses nitinol, a nickel-titanium shape memory alloy, as a displacement-force micro-actuator. An electrical current is used to resistively heat a 'plastically' elongated SMA actuator wire, causing it to contract in response to a thermally-induced phase transformation. The resulting tension creates a moment, imparting rotary motion between two adjacent panels. Mechanical stops are designed into the device to limit its range of motion and to establish positioning accuracy at the termination of deployment. The concept and its operation are discussed in detail, and an analytical dynamic simulation model is presented. The model has been used to perform nondimensionalized parametric design studies.

  1. MHD compressor---expander conversion system integrated with GCR inside a deployable reflector

    Energy Technology Data Exchange (ETDEWEB)

    Tuninetti, G. (Ansaldo S.p.A., Genoa (Italy). Research Div.); Botta, E.; Criscuolo, C.; Riscossa, P. (Ansaldo S.p.A., Genoa (Italy). Nuclear Div.); Giammanco, F. (Pisa Univ. (Italy). Dipt. di Fisica); Rosa-Clot, M. (Florence Univ. (Italy). Dipt. di Fisica)

    1989-04-20

    This work originates from the proposal MHD Compressor-Expander Conversion System Integrated with a GCR Inside a Deployable Reflector''. The proposal concerned an innovative concept of nuclear, closed-cycle MHD converter for power generation on space-based systems in the multi-megawatt range. The basic element of this converter is the Power Conversion Unit (PCU) consisting of a gas core reactor directly coupled to an MHD expansion channel. Integrated with the PCU, a deployable reflector provides reactivity control. The working fluid could be either uranium hexafluoride or a mixture of uranium hexafluoride and helium, added to enhance the heat transfer properties. The original Statement of Work, which concerned the whole conversion system, was subsequently redirected and focused on the basic mechanisms of neutronics, reactivity control, ionization and electrical conductivity in the PCU. Furthermore, the study was required to be inherently generic such that the study was required to be inherently generic such that the analysis an results can be applied to various nuclear reactor and/or MHD channel designs''.

  2. Optimization design combined with coupled structural-electrostatic analysis for the electrostatically controlled deployable membrane reflector

    Science.gov (United States)

    Liu, Chao; Yang, Guigeng; Zhang, Yiqun

    2015-01-01

    The electrostatically controlled deployable membrane reflector (ECDMR) is a promising scheme to construct large size and high precision space deployable reflector antennas. This paper presents a novel design method for the large size and small F/D ECDMR considering the coupled structure-electrostatic problem. First, the fully coupled structural-electrostatic system is described by a three field formulation, in which the structure and passive electrical field is modeled by finite element method, and the deformation of the electrostatic domain is predicted by a finite element formulation of a fictitious elastic structure. A residual formulation of the structural-electrostatic field finite element model is established and solved by Newton-Raphson method. The coupled structural-electrostatic analysis procedure is summarized. Then, with the aid of this coupled analysis procedure, an integrated optimization method of membrane shape accuracy and stress uniformity is proposed, which is divided into inner and outer iterative loops. The initial state of relatively high shape accuracy and uniform stress distribution is achieved by applying the uniform prestress on the membrane design shape and optimizing the voltages, in which the optimal voltage is computed by a sensitivity analysis. The shape accuracy is further improved by the iterative prestress modification using the reposition balance method. Finally, the results of the uncoupled and coupled methods are compared and the proposed optimization method is applied to design an ECDMR. The results validate the effectiveness of this proposed methods.

  3. Development of lightweight, glass mirror segments for the Large Deployable Reflector

    Science.gov (United States)

    Melugin, R. K.; Miller, J. H.; Angel, J. R. P.; Wangsness, P. A. A.; Parks, R. E.

    1986-01-01

    Accomplishments in the development of lightweight, honeycomb-core, sandwich mirror blanks made of borosilicate and high-silica glasses at the University of Arizona for the Large Deployable Reflector program are described. In this paper, work spanning the last 2 years is reported, highlighting a new mirror blank fabrication technique that permits the fabrication of the honeycomb core integrally with the front and back plates of the blank in a single furnace cycle. Two types of mirror blanks made by this method, an off-axis, aspheric segment and a smaller Vycor circular piece, are described. The fabrication of two off-axis, aspheric mirror segments is also described. Cryogenic test results are included on the test of a 38-cm diameter, lightweight, honeycomb core, sandwich mirror made of Pyrex.

  4. Measurement campaigns for selection of optimum on-ground performance verification approach for large deployable reflector antenna

    DEFF Research Database (Denmark)

    Pivnenko, Sergey; Nielsen, Jeppe Majlund; Kim, Oleksiy S.;

    2012-01-01

    This paper describes the measurement campaigns carried out at P-band (435 MHz) for selection of optimum on-ground verification approach for a large deployable reflector antenna (LDA). The feed array of the LDA was measured in several configurations with spherical, cylindrical, and planar near-field...... techniques at near-field facilities in Denmark and in the Netherlands. The measured results for the feed array were then used in calculation of the radiation pattern and gain of the entire LDA. The primary goals for the campaigns were to obtain realistic measurement uncertainty estimates and to investigate...

  5. Parameter estimation of large flexible aerospace structures with application to the control of the Maypole Deployable Reflector

    Science.gov (United States)

    Balas, M. J.

    1981-01-01

    Systems such as the Maypole deployable reflector have a distributed parameter nature. The flexible column and hoop structure and the circular antenna of 30-100 meter diameter which it supports are described by partial, rather than ordinary, differential equations. Progress completed in reduced order modelling andd controller design and digital parameter estimation and control is summarized. Topics covered include depolyment and on-orbit operation; quasi-static (steady state) operation; dynamic distributed parameter system; autoregressive moving average identification; frequency domain procedures; direct or implicit active control; adaptive observers; parameter estimation using a linear reinforcement learning factor; feedback control; and reduced order modeling for nonlinear systems.

  6. Corner reflector deployment for X-band SAR interferometry to monitor the landslide of Carlantino, Daunia Region (Italy)

    Science.gov (United States)

    Bovenga, F.; Refice, A.; Pasquariello, G.

    2012-04-01

    case, for instance, of the Municipality of Carlantino, where PS targets detected by both C- and X-band data correspond to urban structures or peri-urban walls and guard rails, while a large landslide, extending for about 2 km from the hilltop down to the valley, is lacking stable coherent targets, due to the vegetation cover. In order to allow stability monitoring through spaceborne SAR interferometry, a network of passive reflectors was designed and deployed on the area of interest. The Corner Reflectors (CR) were designed for TerraSAR-X stripmap acquisitions, and consist of three triangular metal panels welded perpendicular to each others to form a trihedral shape which ensures that the radar signal is scattered back to the sensor. A small size is preferred to minimize the curvature of the side panels, the effect of wind, the exposition to vandalism, and to allow easier transportation and deployment in the harsh terrain setting. To design the CR network, different factors were taken into account: the visibility of the CR by the satellite in terms of geometry and radiometry, the accessibility of the location on the ground, and the relative distance between CR. The work discusses the problematic aspects of designing and deployment of the CR network and presents preliminary results.

  7. Deployment and design of bi-directional corner reflectors for op-timal ground motion monitoring using InSAR

    NARCIS (Netherlands)

    Caro Cuenca, M.; Dheenathayalan, P.; Rossum, W.L. van; Hoogeboom, P.

    2014-01-01

    SAR interferometry (InSAR) requires coherent radar reflections to measure ground displacements. Howev-er, natural coherent reflectors are not always available due to changes in the scattering properties of the ground, e.g., growing vegetation. Furthermore, the opportunistic nature of InSAR measureme

  8. Joints in deployable space truss structures

    Science.gov (United States)

    Rhodes, M.

    1988-01-01

    Since the response of deployable structural concepts being considered for the Large Deployable Reflector (LDR) backup structure will be dominated by the response of joints, the joint characteristics are significant. An overview is given of the research activities at LaRC on the static behavior of joints for deployable space truss structures. Since a pin-clevis-type joint will be utilized in deployable structures, an experimental research program to characterize the joint parameters which affect stiffness was conducted. An experimental research program was conducted on a second type of joint, referred to as a near-center latch joint. It was used in the center of members on the deployable truss structure for the Control of Flexible Structures (COFS) flight experiment. The test results of the near-center latch joint and the member with the joints indicated that the stiffness of the near-center joint is linear and stiffer than the stiffness of the total member, and that non-linearities in the stiffness characteristics of the total member were due to bending introduced at the ends of the member. The resulting data indicates that stiff linear folding joints can be designed and that bending load paths should be avoided whenever possible. In summary, for deployable structures, special attention to the joint and the structure design is required to minimize the undesirable structural non-linearities.

  9. Concepts, analysis and development for precision deployable space structures

    Science.gov (United States)

    Miller, Richard K.; Thomson, Mark; Hedgepeth, John M.

    1991-01-01

    Several issues surrounding the development of large Precision Segmented Reflector (PSR) designs are investigated. The concerns include nonlinear dynamics of large unruly masses such as the multi-layer thermal insulation of sunshades for instruments such as the precision pointing 20-m-diameter Large Deployable Reflector (LDR). A study of the residual oscillations after bang-bang reorientation maneuvers of a rigid satellite with a string appendage is presented. Application is made to the design of a sunshade (thermal blanket) for the LDE satellite. Another concern is the development of a deployable truss that has minimum structural redundancy (such as the tetrahedral truss) and that can be configured with planar and doubly curved geometries. A kinematically synchronized articulation scheme for a deployable tetrahedral truss is presented. Called the Tetrapac, this truss is currently limited to a planar configuration that has two rings. The final concern is the development and demonstration of hardware that enables astronauts to attach large, cumbersome, and fragile precision reflector segments to an erectable truss structure. This task must be accomplished with a high degree of precision and with relative ease. A design for a Panel Attachment Device (PAD) was developed and manufactured for neutral buoyancy simulations to be performed by LaRC.

  10. Measurements of Antenna Surface for a Millimeter-Wave Space Radio Telescope II; Metal Mesh Surface for Large Deployable Reflector

    CERN Document Server

    Kamegai, Kazuhisa

    2012-01-01

    Large deployable antennas with a mesh surface woven by fine metal wires are an important technology for communications satellites and space radio telescopes. However, it is difficult to make metal mesh surfaces with sufficient radio-frequency (RF) performance for frequencies higher than millimeter waves. In this paper, we present the RF performance of metal mesh surfaces at 43 GHz. For this purpose, we developed an apparatus to measure the reflection coefficient, transmission coefficient, and radiative coefficient of the mesh surface. The reflection coefficient increases as a function of metal mesh surface tension, whereas the radiative coefficient decreases. The anisotropic aspects of the reflection coefficient and the radiative coefficient are also clearly seen. They depend on the front and back sides of the metal mesh surface and the rotation angle. The transmission coefficient was measured to be almost constant. The measured radiative coefficients and transmission coefficients would cause significant degr...

  11. An Intelligent Line Follower Using Ldr Sensor

    Directory of Open Access Journals (Sweden)

    Abdul Hannan1

    2015-11-01

    Full Text Available Line follower robot is a robo car that can follow a path. The path can be visible like a black line on the white surface (or vice-verse. It is an integrated design from the knowledge of Mechanical, Electrical and Computer engineering. This paper presents a 700gm weight of a 9W LDR sensor based line follower robot design and fabrication procedure which always directs along the black mark on the white surface.

  12. Modeling and analysis of a large deployable antenna structure

    Science.gov (United States)

    Chu, Zhengrong; Deng, Zongquan; Qi, Xiaozhi; Li, Bing

    2014-02-01

    One kind of large deployable antenna (LDA) structure is proposed by combining a number of basic deployable units in this paper. In order to avoid vibration caused by fast deployment speed of the mechanism, a braking system is used to control the spring-actuated system. Comparisons between the LDA structure and a similar structure used by the large deployable reflector (LDR) indicate that the former has potential for use in antennas with up to 30 m aperture due to its lighter weight. The LDA structure is designed to form a spherical surface found by the least square fitting method so that it can be symmetrical. In this case, the positions of the terminal points in the structure are determined by two principles. A method to calculate the cable network stretched on the LDA structure is developed, which combines the original force density method and the parabolic surface constraint. Genetic algorithm is applied to ensure that each cable reaches a desired tension, which avoids the non-convergence issue effectively. We find that the pattern for the front and rear cable net must be the same when finding the shape of the rear cable net, otherwise anticlastic surface would generate.

  13. Membrane Shell Reflector Segment Antenna

    Science.gov (United States)

    Fang, Houfei; Im, Eastwood; Lin, John; Moore, James

    2012-01-01

    The mesh reflector is the only type of large, in-space deployable antenna that has successfully flown in space. However, state-of-the-art large deployable mesh antenna systems are RF-frequency-limited by both global shape accuracy and local surface quality. The limitations of mesh reflectors stem from two factors. First, at higher frequencies, the porosity and surface roughness of the mesh results in loss and scattering of the signal. Second, the mesh material does not have any bending stiffness and thus cannot be formed into true parabolic (or other desired) shapes. To advance the deployable reflector technology at high RF frequencies from the current state-of-the-art, significant improvements need to be made in three major aspects: a high-stability and highprecision deployable truss; a continuously curved RF reflecting surface (the function of the surface as well as its first derivative are both continuous); and the RF reflecting surface should be made of a continuous material. To meet these three requirements, the Membrane Shell Reflector Segment (MSRS) antenna was developed.

  14. Reflector homogenization

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, R.; Ragusa, J.; Santandrea, S. [Commissariat a l' Energie Atomique, Direction de l' Energie Nucleaire, Service d' Etudes de Reacteurs et de Modelisation Avancee, CEA de Saclay, DM2S/SERMA 91 191 Gif-sur-Yvette cedex (France)]. e-mail: richard.sanchez@cea.fr

    2004-07-01

    The problem of the determination of a homogeneous reflector that preserves a set of prescribed albedo is considered. Duality is used for a direct estimation of the derivatives needed in the iterative calculation of the optimal homogeneous cross sections. The calculation is based on the preservation of collapsed multigroup albedo obtained from detailed reference calculations and depends on the low-order operator used for core calculations. In this work we analyze diffusion and transport as low-order operators and argue that the P{sub 0} transfers are the best choice for the unknown cross sections to be adjusted. Numerical results illustrate the new approach for SP{sub N} core calculations. (Author)

  15. Surface Optimization Techniques for Deployable Reflectors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Existing communications systems for spacecraft provide a choice between either large aperture (>3m) or high frequency (>X-band), but not both. These systems...

  16. Collapsible structure for an antenna reflector

    Science.gov (United States)

    Trubert, M. R. (Inventor)

    1973-01-01

    A collapsible support for an antenna reflector for use in supporting spacecraft antennas is described. The support has a regid base and a number of struts which are pivoted at the base. The deployment of the struts and their final configuration for supporting the antenna are illustrated.

  17. Multi-objective optimal sensor deployment for satellite antenna reflector%星载天线反射面传感器多目标优化部署方案

    Institute of Scientific and Technical Information of China (English)

    李文博; 王有懿; 赵志刚; 赵阳

    2012-01-01

    传感器数量和位置的优化部署,是实现大型星载天线在轨获取高精度模态参数亟待解决的关键技术.为克服以往研究中采用单一优化准则所带来的局限性和片面性,设计观测信息正交性最大和能量最大的双优化准则,引入NSGA -Ⅱ算法进行多目标传感器优化部署求解.考虑到该算法仅适合连续性优化变量,存在收敛速度及多样性保持方面的不足,对其在编码方式和遗传算子设计两方面进行改进,并给出所有指标权重组合且分布均匀的Pareto最优解集.设计四种优化方案,进行仿真比较可得:基于改进NSGA -II算法的星载天线传感器多目标优化部署方案,较其他三种方案在性能指标上更优,且该方案更加符合实际工程的多指标优化设计要求,保证优化结果具有更高的灵活性和适应性.%To determine the number and locations of deployed sensors is the key technology to be solved for obtaining high precision modal parameters of large satellite antenna reflector on-orbit. To Bvoid the limitations and one-sidedness of single-objective criterion used in previous research work, the double-objective criterions were designed, which contain the largest orthogonality and the highest vibration energy of observed signals. NSGA- II algorithm was introduced in salving multi-objective optimization problem of sensor deployment. Considering the limitation that only continuous variables can be applicable and the deficiencies in convergence speed and diversity holding of NSGA-1, the coding and genetic operators were improved. Comparing the results of four cases with different single-objective and multi-objective criterions, the solutions based on improved NSGA- D are the best among these four cases according to all indicators, which are of greater flexibility and adaptability and can obtain the uniform distributed Pareto solution set, including all weight combinations of muki objectives. It can more

  18. Affordable Unfurlable Fan-Fold Wrapable Reflector for Small and Large Apertures Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Deployable Space Systems (DSS) will focus the proposed SBIR program on the development and concept feasibility of an innovative deployable mesh/membrane reflector...

  19. State-of-the-art: prostate LDR brachytherapy.

    Science.gov (United States)

    Voulgaris, S; Nobes, J P; Laing, R W; Langley, S E M

    2008-01-01

    This article on low dose rate (LDR) prostate brachytherapy reviews long-term results, patient selection and quality of life issues. Mature results from the United States and United Kingdom are reported and issues regarding definitions of biochemical failure are discussed. Latest data comparing brachytherapy with radical prostatectomy or no definitive treatment and also the risk of secondary malignancies after prostate brachytherapy are presented. Urological parameters of patient selection and quality of life issues concerning urinary, sexual and bowel function are reviewed. The position of prostate brachytherapy next to surgery as a first-line treatment modality is demonstrated.

  20. Coupling in reflector arrays

    DEFF Research Database (Denmark)

    Appel-Hansen, Jørgen

    1968-01-01

    In order to reduce the space occupied by a reflector array, it is desirable to arrange the array antennas as close to each other as possible; however, in this case coupling between the array antennas will reduce the reflecting properties of the reflector array. The purpose of the present communic...

  1. Beam-Steerable Flat-Panel Reflector Antenna

    Science.gov (United States)

    Lee, Choon Sae; Lee, Chanam; Miranda, Felix A.

    2005-01-01

    Many space applications require a high-gain antenna that can be easily deployable in space. Currently, the most common high-gain antenna for space-born applications is an umbrella-type reflector antenna that can be folded while being lifted to the Earth orbit. There have been a number of issues to be resolved for this type of antenna. The reflecting surface of a fine wire mesh has to be light in weight and flexible while opening up once in orbit. Also the mesh must be a good conductor at the operating frequency. In this paper, we propose a different type of high-gain antenna for easy space deployment. The proposed antenna is similar to reflector antennas except the curved main reflector is replaced by a flat reconfigurable surface for easy packing and deployment in space. Moreover it is possible to steer the beam without moving the entire antenna system.

  2. CNGS Reflector installed

    CERN Multimedia

    2006-01-01

    A major component that will help target the CNGS neutrino beam for its 732km journey through the earth's crust, from CERN to the Gran Sasso laboratory in Italy, has been installed in its final position. The transport of the huge magnetic horn reflector through the CNGS access gallery. A team from CNGS and TS/IC, and the contractors DBS, transported the magnetic horn reflector on 5th December, in a carefully conducted operation that took just under two hours. The reflector is 7m long, 1.6m in diameter and 1.6 tonnes in weight. With only a matter of centimetres to spare on either side, the reflector was transported through the CNGS access gallery, before being installed in the experiment's target chamber. The larger of two magnetic horns, the reflector will help refocus sprays of high energy pions and kaons emitted after a 0.5MW stream of protons from the Super Proton Synchrotron (SPS) strikes nucleons in a graphite target. The horns are toroidal magnetic lenses and work with high pulsed currents: 150 kA f...

  3. Pemantau Lalu Lintas dengan Sensor LDR Berbasis Mikrokontroler ATmega16

    Directory of Open Access Journals (Sweden)

    Adam Vrileuis

    2013-04-01

    Full Text Available This system was designed to monitor the condition of traffic by measuring the speed and density of vehicles on the road. This system uses Light Dependent Sensor (LDR that can detect the vehicles when there is no light stimulus. Light Dependent Sensor is used as a switch in the circuit. When the light on the sensor is blocked, it provides a response to microcontroller to turn on and turn off the timer, and to run the counter. Theoretically, the condition of traffic flow, such as traffic jams, can be indicated on the vehicle speed and density. The speed and density data were processed by microcontroller using C programming for RISC AVR (Alf and Vegard’s RISC processor. Timing data obtained from the timer and counter were computed by applying arithmetic process to describe the traffic condition. Kinematics theory was applied to find the speedy by multiplying the distance between the sensors which was determined when the vehicles passing the sensors. This system is able to detect congestion at a road if the speed is lower and the density is higher than the setup values.

  4. Deployable truss structure advanced technology

    Science.gov (United States)

    Dyer, J. E.; Dudeck, M. P.

    1986-01-01

    The 5-meter technology antenna program demonstrated the overall feasibility of integrating a mesh reflector surface with a deployable truss structure to achieve a precision surface contour compatible with future, high-performance antenna requirements. Specifically, the program demonstrated: the feasibility of fabricating a precision, edge-mounted, deployable, tetrahedral truss structure; the feasibility of adjusting a truss-supported mesh reflector contour to a surface error less than 10 mils rms; and good RF test performance, which correlated well with analytical predictions. Further analysis and testing (including flight testing) programs are needed to fully verify all the technology issues, including structural dynamics, thermodynamics, control, and on-orbit RF performance, which are associated with large, deployable, truss antenna structures.

  5. Methods for prostate stabilization during transperineal LDR brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Podder, Tarun; Yu Yan [Department of Radiation Oncology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 19107 (United States); Sherman, Jason [Department of Medical Physics, University of Buffalo, Buffalo, NY 14260 (United States); Rubens, Deborah; Strang, John [Departments of Imaging Science and Surgery, University of Rochester, Rochester, NY 14642 (United States); Messing, Edward [Departments of Urology and Surgery, University of Rochester, Rochester, NY 14642 (United States); Ng, Wan-Sing [School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798 (Singapore)

    2008-03-21

    In traditional prostate brachytherapy procedures for a low-dose-rate (LDR) radiation seed implant, stabilizing needles are first inserted to provide some rigidity and support to the prostate. Ideally this will provide better seed placement and an overall improved treatment. However, there is much speculation regarding the effectiveness of using regular brachytherapy needles as stabilizers. In this study, we explored the efficacy of two types of needle geometries (regular brachytherapy needle and hooked needle) and several clinically feasible configurations of the stabilization needles. To understand and assess the prostate movement during seed implantation, we collected in vivo data from patients during actual brachytherapy procedures. In vitro experimentation with tissue-equivalent phantoms allowed us to further understand the mechanics behind prostate stabilization. We observed superior stabilization with the hooked needles compared to the regular brachytherapy needles (more than 40% in bilateral parallel needle configuration). Prostate movement was also reduced significantly when regular brachytherapy needles were in an angulated configuration as compared to the parallel configuration (more than 60%). When the hooked needles were angulated for stabilization, further reduction in prostate displacement was observed. In general, for convenience of dosimetric planning and to avoid needle collision, all needles are desired to be in a parallel configuration. In this configuration, hooked needles provide improved stabilization of the prostate. On the other hand, both regular and hooked needles appear to be equally effective in reducing prostate movement when they are in angulated configurations, which will be useful in seed implantation using a robotic system. We have developed nonlinear spring-damper model for the prostate movement which can be used for adapting dosimetric planning during brachytherapy as well as for developing more realistic haptic devices and

  6. Non-Destructive Evaluation of Kissing Bonds using Local Defect Resonance (LDR) Spectroscopy: A Simulation Study

    Science.gov (United States)

    Delrue, S.; Tabatabaeipour, M.; Hettler, J.; Van Den Abeele, K.

    With the growing demand from industry to optimize and further develop existing Non-Destructive Testing & Evaluation (NDT&E) techniques or new methods to detect and characterize incipient damage with high sensitivity and increased quality, ample efforts have been devoted to better understand the typical behavior of kissing bonds, such as delaminations and cracks. Recently, it has been shown experimentally that the nonlinear ultrasonic response of kissing bonds could be enhanced by using Local Defect Resonance (LDR) spectroscopy. LDR spectroscopy is an efficient NDT technique that takes advantage of the characteristic fre- quencies of the defect (defect resonances) in order to provide maximum acoustic wave-defect interaction. In fact, for nonlinear methodologies, the ultrasonic excitation of the sample should occur at either multiples or integer ratios of the characteristic defect resonance frequencies, in order to obtain the highest signal-to-noise response in the nonlinear LDR spectroscopy. In this paper, the potential of using LDR spectroscopy for the detection, localization and characterization of kissing bonds is illustrated using a 3D simulation code for elastic wave propagation in materials containing closed but dynamically active cracks or delaminations. Using the model, we are able to define an appropriate method, based on the Scaling Subtraction Method (SSM), to determine the local defect resonance frequencies of a delamination in a composite plate and to illustrate an increase in defect nonlinearity due to LDR. The simulation results will help us to obtain a better understanding of the concept of LDR and to assist in the further design and testing of LDR spectroscopy for the detection, localization and characterization of kissing bonds.

  7. Development of Full-Scale Ultrathin Shell Reflector

    Directory of Open Access Journals (Sweden)

    Durmuş Türkmen

    2012-01-01

    Full Text Available It is aimed that a new ultrathin shell composite reflector is developed considering different design options to optimize the stiffness/mass ratio, cost, and manufacturing. The reflector is an offset parabolic reflector with a diameter of 6 m, a focal length of 4.8 m, and an offset of 0.3 m and has the ability of folding and self-deploying. For Ku-band missions a full-scale offset parabolic reflector antenna is designed by considering different concepts of stiffening: (i reflective surface and skirt, (ii reflective surface and radial ribs, and (iii reflective surface, skirt, and radial ribs. In a preliminary study, the options are modeled using ABAQUS finite element program and compared with respect to their mass, fundamental frequency, and thermal surface errors. It is found that the option of reflective surface and skirt is more advantageous. The option is further analyzed to optimize the stiffness/mass ratio considering the design parameters of material thickness, width of the skirt, and ply angles. Using the TOPSIS method is determined the best reflector concept among thirty different designs. Accordingly, new design can be said to have some advantages in terms of mass, natural frequency, number of parts, production, and assembly than both SSBR and AstroMesh reflectors.

  8. Reflectors to Focus Wave Energy

    DEFF Research Database (Denmark)

    Kramer, Morten; Frigaard, Peter

    2005-01-01

    Wave Energy Converters (WEC’s) extract wave energy from a limited area, often a single point or line even though the wave energy is generally spread out along the wave crest. By the use of wave reflectors (reflecting walls) the wave energy is effectively focused and increased by approximately 30......-50%. Clearly longer wave reflectors will focus more wave energy than shorter wave reflectors. Thus the draw back is the increased wave forces for the longer wave reflectors. In the paper a procedure for calculating the energy efficiency and the wave forces on the reflectors are described, this by use of a 3D...... boundary element method. The calculations are verified by laboratory experiments and a very good agreement is found. The paper gives estimates of possible power benefit for different wave reflector geometries and optimal geometrical design parameters are specified. On this basis inventors of WEC’s can...

  9. The Planck Telescope reflectors

    Science.gov (United States)

    Stute, Thomas

    2004-09-01

    The mechanical division of EADS-Astrium GmbH, Friedrichshafen is currently engaged with the development, manufacturing and testing of the advanced dimensionally stable composite reflectors for the ESA satellite borne telescope Planck. The objective of the ESA mission Planck is to analyse the first light that filled the universe, the cosmic microwave background radiation. Under contract of the Danish Space Research Institute and ESA EADS-Astrium GmbH is developing the all CFRP primary and secondary reflectors for the 1.5-metre telescope which is the main instrument of the Planck satellite. The operational frequency ranges from to 25 GHz to 1000 GHz. The demanding high contour accuracy and surface roughness requirements are met. The design provides the extreme dimensional stability required by the cryogenic operational environment at around 40 K. The elliptical off-axis reflectors display a classical lightweight sandwich design with CFRP core and facesheets. Isostatic mounts provide the interfaces to the telescope structure. Protected VDA provides the reflecting surface. The manufacturing is performed at the Friedrichshafen premises of EADS-Space Transportation GmbH, the former Dornier composite workshops. Advanced manufacturing technologies like true angle lay-up by CNC fibre placement and filament winding are utilized. The protected coating is applied at the CAHA facilities at the Calar Alto Observatory, Spain. The exhaustive environmental testing is performed at the facilities of IABG, Munich (mechanical testing) and for the cryo-optical tests at CSL Liege. The project is in advanced state with both Qualification Models being under environmental testing. The flight models will be delivered in 2004. The paper gives an overview over the requirements and the main structural features how these requirements are met. Special production aspects and available test results are reported.

  10. Advanced Manufacture of Reflectors

    Energy Technology Data Exchange (ETDEWEB)

    Angel, Roger [University of Arizona

    2014-12-17

    The main project objective has been to develop an advanced gravity sag method for molding large glass solar reflectors with either line or point focus, and with long or short focal length. The method involves taking standard sized squares of glass, 1.65 m x 1.65 m, and shaping them by gravity sag into precision steel molds. The method is designed for high volume manufacture when incorporated into a production line with separate pre-heating and cooling. The performance objectives for the self-supporting glass mirrors made by this project include mirror optical accuracy of 2 mrad root mean square (RMS), requiring surface slope errors <1 mrad rms, a target not met by current production of solar reflectors. Our objective also included development of new methods for rapidly shaping glass mirrors and coating them for higher reflectivity and soil resistance. Reflectivity of 95% for a glass mirror with anti-soil coating was targeted, compared to the present ~94% with no anti-soil coating. Our mirror cost objective is ~$20/m2 in 2020, a significant reduction compared to the present ~$35/m2 for solar trough mirrors produced for trough solar plants. During the first year a custom batch furnace was built to develop the method with high power radiative heating to simulate transfer of glass into a hot slumping zone in a production line. To preserve the original high polish of the float glass on both front and back surfaces, as required for a second surface mirror, the mold surface is machined to the required shape as grooves which intersect the glass at cusps, reducing the mold contact area to significantly less than 1%. The mold surface is gold-plated to reflect thermal radiation. Optical metrology of glass replicas made with the system has been carried out with a novel, custom-built test system. This test provides collimated, vertically-oriented parallel beams from a linear array of co-aligned lasers translated in a perpendicular direction across the reflector. Deviations of

  11. Advanced Manufacture of Reflectors

    Energy Technology Data Exchange (ETDEWEB)

    Angel, Roger [Univ. of Arizona, Tucson, AZ (United States)

    2014-12-17

    The main project objective has been to develop an advanced gravity sag method for molding large glass solar reflectors with either line or point focus, and with long or short focal length. The method involves taking standard sized squares of glass, 1.65 m x 1.65 m, and shaping them by gravity sag into precision steel molds. The method is designed for high volume manufacture when incorporated into a production line with separate pre-heating and cooling. The performance objectives for the self-supporting glass mirrors made by this project include mirror optical accuracy of 2 mrad root mean square (RMS), requiring surface slope errors less than 1 mrad rms, a target not met by current production of solar reflectors. Our objective also included development of new methods for rapidly shaping glass mirrors and coating them for higher reflectivity and soil resistance. Reflectivity of 95% for a glass mirror with anti-soil coating was targeted, compared to the present ~94% with no anti-soil coating. Our mirror cost objective is ~$20/m2 in 2020, a significant reduction compared to the present ~$35/m2 for solar trough mirrors produced for trough solar plants.

  12. Freeform reflectors for architectural lighting.

    Science.gov (United States)

    Zhu, Ruidong; Hong, Qi; Zhang, Hongxia; Wu, Shin-Tson

    2015-12-14

    We propose an improved method to design freeform reflectors for architectural lighting: one for accent lighting and another for large area wall washing. The designed freeform reflectors effectively distribute light fluxes over the target surfaces, and generate appropriate illumination patterns for comfortable visual environments, which provides greater flexibility for lighting designs, allows many challenging designs, and improves energy-efficiency simultaneously.

  13. Environmental Degradation of Solar Reflectors

    Science.gov (United States)

    Bouquet, F. L.

    1985-01-01

    Report presents results of study of atmospheric degradation of large solar reflectors for power generators. Three general types of reflective surfaces investigated. Report also describes computer buildup and removal (by rain and dew) of contamination from reflectors. Data used to determine effects of soil buildup and best method and frequency of washing at various geographic locations.

  14. Cold Crystal Reflector Filter Concept

    CERN Document Server

    Muhrer, G

    2014-01-01

    In this paper the theoretical concept of a cold crystal reflector filter will be presented. The aim of this concept is to balance the shortcoming of the traditional cold polycrystalline reflector filter, which lies in the significant reduction of the neutron flux right above (in energy space) or right below (wavelength space) the first Bragg edge.

  15. Mutual interference effects in closely-located HDR and LDR WPANs

    DEFF Research Database (Denmark)

    Prasad, Ramjee; Monti, M.; De Sanctis, M.;

    2009-01-01

    Wireless Personal Area Networks (WPANs) are short-range ad-hoc networks centered around a person that make use of unlicensed bands for data transmission. Several transmission schemes such as Ultra Wide Band (UWB) or Spread Spectrum (SS) have been proposed for both Low Data Rate (LDR) and High Data...

  16. Reflector Surface Error Compensation in Dual-Reflector Antennas

    Science.gov (United States)

    Jamnejad, Vahraz; Imbriale, William

    2010-01-01

    By probing the field on a small subreflector at a minimal number of points, the main reflector surface errors can be obtained and subsequently used to design a phase-correction subreflector that can compensate for main reflector errors. The compensating phase-error profile across the subreflector can be achieved either by a surface deformation or by the use of an array of elements such as patch antennas that can cause a phase shift between the incoming and outgoing fields. The second option is of primary interest here, but the methodology can be applied to either case. The patch array is most easily implemented on a planar surface. Therefore, the example of a flat subreflector and a parabolic main reflector (a Newtonian dual reflector system) is considered in this work. The subreflector is assumed to be a reflector array covered with patch elements. The phase variation on a subreflector can be detected by a small number of receiving patch elements (probes). By probing the phase change at these few selected positions on the subreflector, the phase error over the entire surface can be recovered and used to change the phase of all the patch elements covering the subreflector plane to compensate for main reflector errors. This is accomplished by using a version of sampling theorem on the circular aperture. The sampling is performed on the phase-error function on the circular aperture of the main reflector by a method developed using Zernike polynomials. This method is based upon and extended from a theory previously proposed and applied to reflector aperture integration. This sampling method provides for an exact retrieval of the coefficients of up to certain orders in the expansion of the phase function, from values on a specifically calculated set of points in radial and azimuthal directions in the polar coordinate system, on the circular reflector aperture. The corresponding points on the subreflector are then obtained and, by probing the fields at these points, a

  17. Active Reflectors: Possible Solutions Based on Reflectarrays and Fresnel Reflectors

    Directory of Open Access Journals (Sweden)

    Lorena Cabria

    2009-01-01

    Full Text Available An overview about some of the recent Spanish developments on active reflectors is presented. In the first part, a novel beamsteering active reflectarray is deeply studied. It is based on implementing in each elementary radiator an IQ modulator structure, in which amplitude and phase control of the scattered field is achieved. Finally, a special effort is made in offering solutions to overcome the active antenna integration problems. In the second part, the active concept is firstly extended to Fresnel reflectors. Thanks to the development of a proper simulator, this special structure can be easily analysed. This simulator allows the study of performance of this kind of reflectors and, applying evolutionary algorithms, to find optimal configurations of reflector in accordance with the given specifications for the conformal radiation pattern.

  18. Shape Memory Polymer Self-Deploying Membrane Reflectors

    Science.gov (United States)

    2007-01-30

    structure composed of conventional lightweight composites. The structure and mirrors are folded into a compressed package for launch stowage (Figure I a). On...for interceptor missiles. In this approach, a mirror’s final figure and finish is achieved by thermoforming a thin layer of SMP at the surface of a...2007 thermoformed SMP layer replicates the mold’s figure and finish, rather than the casting approach in the current program for membrane mirrors. 6.8

  19. Reflectors for SAR performance testing.

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter

    2008-01-01

    Synthetic Aperture Radar (SAR) performance testing and estimation is facilitated by observing the system response to known target scene elements. Trihedral corner reflectors and other canonical targets play an important role because their Radar Cross Section (RCS) can be calculated analytically. However, reflector orientation and the proximity of the ground and mounting structures can significantly impact the accuracy and precision with which measurements can be made. These issues are examined in this report.

  20. Uncertainty in delivered dose resulting from the distribution of source activities in a Selectron LDR afterloader

    Energy Technology Data Exchange (ETDEWEB)

    Ho, A.K.; Castiglione, Robert; Podgorsak, M.B.; Sibata, C.H.; Shin, K.H. (Roswell Park Cancer Inst., Buffalo, NY (United States). Dept. of Radiation Medicine)

    1994-11-01

    The uncertainty in the delivered dose resulting from the distribution of [sup 137]Cs source activity in a clinical Selectron LDR unit has been studied. A comparison is made of the dose delivered to a point 'A' in an implant with sources of equal activity to the actual dose delivered in the same implant with source activities randomly chosen from the population in the afterloader. (author).

  1. Structures for remotely deployable precision antennas

    Science.gov (United States)

    Hedgepeth, J. M.

    1989-01-01

    Future space missions such as the Earth Science Geostationary Platform (ESGP) will require highly accurate antennas with apertures that cannot be launched fully formed. The operational orbits are often inaccessible to manned flight and will involve expendable launch vehicles such as the Delta or Titan. There is therefore a need for completely deployable antenna reflectors of large size capable of efficiently handling millimeter wave electromagnetic radiation. The parameters for the type of mission are illustrated. The logarithmic plot of frequency versus aperture diameter shows the regions of interest for a large variety of space antenna applications, ranging from a 1500-meter-diameter radio telescope for low frequencies to a 20-meter-diameter infrared telescope. For the ESGP, a major application is the microwave radiometry at high frequencies for atmospheric sounding. Almost all existing large antenna reflectors for space employ a mesh-type reflecting surface. Examples are shown and discussed which deal with the various structural concepts for mesh antennas. Fortunately, those concepts are appropriate for creating the very large apertures required at the lower frequencies for good resolution. The emphasis is on the structural concepts and technologies that are appropriate to fully automated deployment of dish-type antennas with solid reflector surfaces. First the structural requirements are discussed. Existing concepts for fully deployable antennas are then described and assessed relative to the requirements. Finally, several analyses are presented that evaluate the effects of beam steering and segmented reflector design on the accuracy of the antenna.

  2. Local deformation method for measuring element tension in space deployable structures

    Directory of Open Access Journals (Sweden)

    Belov Sergey

    2017-01-01

    Full Text Available The article describes the local deformation method to determine the tension of cord and thin membrane elements in space deployable structure as antenna reflector. Possible measuring instrument model, analytical and numerical solutions and experimental results are presented. The boundary effects on measurement results of metallic mesh reflector surface tension are estimated. The study case depicting non-uniform reflector surface tension is considered.

  3. Key technologies for high-accuracy large mesh antenna reflectors

    Science.gov (United States)

    Meguro, Akira; Harada, Satoshi; Watanabe, Mitsunobu

    2003-12-01

    Nippon Telephone and Telegram Corporation (NTT) continues to develop the modular mesh-type deployable antenna. Antenna diameter can be changed from 5 m to about 20 m by changing the number of modules used with surface accuracy better than 2.4 mm RMS (including all error factors) with sufficient deployment reliability. Key technologies are the antenna's structural design, the deployment mechanism, the design tool, the analysis tool, and modularized testing/evaluation methods. This paper describes our beam steering mechanism. Tests show that it yields a beam pointing accuracy of better than 0.1°. Based on the S-band modular mesh antenna reflector, the surface accuracy degradation factors that must be considered in designing the new antenna are partially identified. The influence of modular connection errors on surface accuracy is quantitatively estimated. Our analysis tool SPADE is extended to include the addition of joint gaps. The addition of gaps allows non-linear vibration characteristics due to gapping in deployment hinges to be calculated. We intend to design a new type of mesh antenna reflector. Our new goal is an antenna for Ku or Ka band satellite communication. For this mission, the surface shape must be 5 times more accurate than is required for an S-band antenna.

  4. Jet screech reduction with perforated flat reflector

    Science.gov (United States)

    Khan, Md. Tawhidul Islam; Teramoto, Kenbu; Matsuo, Shigeru; Setoguchi, Toshiaki

    2008-09-01

    In the present experimental study, investigations have been carried out to evaluate the performance of the new control technique of jet screech with different perforated flat reflectors. Mainly two types of porous flat reflectors had been used in the experiment. One reflector (reflector-V) designed for placing the reflector surface vertical to the jet axis, when, another type of reflector (reflector-H) designed for placing the reflecting surface horizontal to the jet axis. In both cases the reflectors had been placed at the nozzle (base tube with uniform cross-sectional area) exit. The diameter of the reflector-V was 15D when the diameter of the reflector-H was 10D. The porous area of the reflector-V was 6D and 4.5D for reflector-H where D indicated the diameter of the nozzle exit. The placement of the reflector at the exit of the nozzle reduces the sound pressure at the nozzle exit. Thus the muted sound can not excite the unstable disturbance at the nozzle exit and the loop of the feedback mechanism disappeared, finally, the generation of jet screech be cancelled. The suction space located at the back side of the porous surface of the reflector-V improves the efficiency of the screech control technique. However, in the case of reflector-H, the receptivity process of feedback loop had been controlled by reducing the disturbances at the effective shock fronts as well as at the nozzle exit. The performance of the proposed method was verified with a flat reflector concept and good performance in jet screech suppression has been confirmed in the case of porous reflector.

  5. Jet Screech Reduction with Perforated Flat Reflector

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In the present experimental study, investigations have been carried out to evaluate the performance of the new control technique of jet screech with different perforated flat reflectors. Mainly two types of porous flat reflectors had been used in the experiment. One reflector (reflector-V) designed for placing the reflector surface vertical to the jet axis, when, another type of reflector (reflector-H) designed for placing the reflecting surface horizontal to the jet axis. In both cases the reflectors had been placed at the nozzle (base tube with uniform cross-sectional area)exit. The diameter of the reflector-V was 15D when the diameter of the reflector-H was 10D. The porous area of the reflector-V was 6D and 4.5D for reflector-H where D indicated the diameter of the nozzle exit. The placement of the reflector at the exit of the nozzle reduces the sound pressure at the nozzle exit. Thus the muted sound can not excite the unstable disturbance at the nozzle exit and the loop of the feedback mechanism disappeared, finally,the generation of jet screech be cancelled. The suction space located at the back side of the porous surface of the reflector-V improves the efficiency of the screech control technique. However, in the case of reflector-H, the receptivity process of feedback loop had been controlled by reducing the disturbances at the effective shock fronts as well as at the nozzle exit. The performance of the proposed method was verified with a flat reflector concept and good performance in jet screech suppression has been confirmed in the case of porous reflector.

  6. Feasibility of applying the new improved PCR/LDR/capillary electrophoresis on prenatal diagnosis of fetal beta thalassaemia

    Directory of Open Access Journals (Sweden)

    Xi LIAO

    2014-03-01

    Full Text Available Objective  To investigate the feasibility of applying new improved polymerase chain reaction (PCR/ligase detection reaction (LDR/capillary electrophoresis to the prenatal diagnosis of fetal β thalassemia from maternal plasma. Methods  The mixture of different concentrations of normal DNA and trace β-thalassemia mutation heterozygous DNA were used for PCR, and the amplification products obtained thereafter were used for LDR. The ligation product was detected by capillary electrophoresis to demonstrate the sensitivity. Results  The amplification products containing same concentration of CD17 (A→T mutation were used as LDR template, 8U DNA ligase reaction was performed. LDR products were analyzed by genetic analyzer CEQ8000 type electrophoresis with a detection sensitivity of 1:5000. Product peak area decreased with the increase of normal peripheral blood DNA concentration gradient. When the concentration reached to 1:10 000, it would be hard to distinguish the product peak and miscellaneous peak. The LDR product was not detected in the product of negative control without CD17 (A→T mutation. The LDR results of normal maternal plasma DNA added 20pg CD17 (A→T heterozygous mutation in peripheral blood DNA amplification products revealed that the product peaks could be clearly distinguished from miscellaneous peaks. Conclusion  The new improved PCR/LDR/capillary electrophoresis technology is expected to be used in plasma DNA tests to prenatal diagnosis of fetal beta thalassaemia in pregnant women. DOI: 10.11855/j.issn.0577-7402.2014.03.06

  7. Offloading techniques for large deployable space structures

    Science.gov (United States)

    Caravaggio, Levino; Golob, Alex

    1992-01-01

    The validation and verification of large deployable space structures are continual challenges which face the integration and test engineer today. Spar Aerospace Limited has worked on various programs in which such structure validation was required and faces similar tasks in the future. This testing is reported and the different offloading and deployment methods which were used, as well as the proposed methods which will be used on future programs, are described. Past programs discussed include the Olympus solar array ambient and thermal vacuum deployments, and the Anik-E array and reflector deployments. The proposed MSAT reflector and boom ambient deployment tests, as well as the proposed RADARSAT Synthetic Aperture Radar (SAR) ambient and thermal vacuum deployment tests will also be presented. A series of tests relating to various component parts of the offloading equipment systems was required. These tests included the characterization and understanding of linear bearings and large (180 in-lbf) constant force spring motors in a thermal vacuum environment, and the results from these tests are presented.

  8. Transport of the CNGS reflector.

    CERN Multimedia

    Maximilien Brice

    2005-01-01

    The CNGS magnetic horn reflectorwas transported on 5 December 2005 through the facility's access gallery. The reflector - a major component that will help target the CNGS neutrino beam for its 732km journey through the earth's crust, from CERN to the Gran Sasso laboratory in Italy - is 7m long, 1.6m in diameter and 1.6 tonnes in weight.

  9. Polarization losses in reflector antennas

    Science.gov (United States)

    Safak, M.; Yazgan, E.

    1985-08-01

    Various definitions for polarization-loss efficiency of Cassegrainian and front-fed reflectors are compared. The effects of flare angle, feed taper and the feed pattern asymmetry on the polarization-loss efficiency are investigated. The definitions based on aperture fields are shown to be inadequate and far fields must be used for calculating the polarization losses.

  10. A New Space Robot End-Effector for On-Orbit Reflector Assembly

    Science.gov (United States)

    2005-07-13

    Space antennas with hexagonal reflectors are planed for ETS-VIII and for VSOP -2. These antennas will be deployed in orbit, but could be a good prototype...Hirabayashi, P.G. Edwards and D.W.Murphy, Proceedings of the VSOP Symposium(2000) [3] S.Nishida, R.Okamura: "Onboard Assembling of Large Space Telescope by

  11. Tunable reflector with active magnetic metamaterials.

    Science.gov (United States)

    Deng, Tianwei; Huang, Ruifeng; Tang, Ming-Chun; Tan, Peng Khiang

    2014-03-24

    We placed active magnetic metamaterials on metallic surface to implement a tunable reflector with excellent agile performance. By incorporating active elements into the unit cells of the magnetic metamaterial, this active magnetic metamaterial can be tuned to switch function of the reflector among a perfect absorber, a perfect reflector and a gain reflector. This brings about DC control lines to electrically tune the active magnetic metamaterial with positive loss, zero loss and even negative loss. The design, analytical and numerical simulation methods, and experimental results of the tunable reflector are presented.

  12. Fifteen Years of Synthetic Aperture Radar Calibration Using Trihedral Reflectors at the Alaska Satellite Facility

    Science.gov (United States)

    Albright, W.; Atwood, D.; Lawlor, O. S.; Utley, P.; Slater, C.

    2006-12-01

    For the past 15 years, the Alaska Satellite Facility (ASF) has provided calibration support for singly polarized SAR datasets in C-band (ERS-1, ERS-2, and RADARSAT-1 and L-Band (JERS-1. Passive point targets like trihedral corner reflectors offer a reliable and well established means to perform radiometric, geometric, and impulse response measurements for SAR calibration. Routine support of an array of corner reflectors in interior Alaska has permitted ASF an opportunity to monitor satellite health, calibrate SAR processors, and experiment with new reflector designs. Corner reflectors offer the advantages of low maintenance and low cost compared to active devices such as transponders. In order to maintain radar cross section, as the microwave wavelength get longer, so too does the size of the reflector. Increased size means decreased portability, exacerbating the difficulty of providing calibration support in remote locations. In response, ASF is developing low cost, light weight corner reflectors that can be deployed with minimal effort and no maintenance. These efforts will help to extend our present calibration efforts to more remote locations. But more importantly, these designs are expected to play an important role in Permanent Scatterer InSAR (PS-InSAR) methodology. The use of corner reflector arrays in support PS-InSAR may provide new means for monitoring terrain displacements in regions of heavy vegetation. This paper presents some long term measurements from ASF's array of corner reflectors, outlines improvements performed on trihedral corner reflectors, and describes current efforts at ASF to support the next generation of SAR missions and techniques.

  13. Perbandingan NPL, LDR, CAR, ROA, dan BOPO Antara Bank BNI Dan Bank BUMN Lain

    Directory of Open Access Journals (Sweden)

    Tri Wahyuningsih

    2016-09-01

    Full Text Available This study aims to analyze the differences in financial performance of Bank BNI and other BUMN Banks by the measuring the ratio of Non Performing Loan (NPL, Loan to Deposit Ratio (LDR, Adecuacy Capital Ratio (CAR, Return on Assets (ROA and BOPO. The study was conducted by using descriptive analysis method. The results of this study explained that the performance NPL, LDR, and Bank BNI's CAR on average during the past eight semesters was still better than BUMN Banks on average, while the performance of ROA and BOPO remained below the average Revenues and Operating Expenses of Operational Income of  Bank BUMN. The results also showed that all BUMN banks still showed good and healthy performance and in accordance with the provisions set by Bank Indonesia. This study also presented the strategy undertaken by Bank BNI to improve its financial performance, that is, the business synergy of all units unit, growth in good-quality assets, optimization of the customer engagement, strengthening the network and develop alliances, optimization of existing resources and simplification of processes, and enhancing customer experiences through improving processes and business models to  digital banking. Keywords: Non-Performing Loans, Loan to Deposit Ratio, Capital Adequacy Ratio, Return on Assets, Revenues and Operating Expenses of Operational Income, Bank BNI, Bank BUMN.

  14. Treatability study for the bench-scale solidification of nonincinerable LDR low-level mixed waste

    Energy Technology Data Exchange (ETDEWEB)

    Gering, K.L.

    1993-01-01

    The focus of this report is the solidification of nonincinerable, land disposal restricted (LDR) low-level mixed waste generated at the Idaho National Engineering Laboratory. Benchscale solidification was performed on samples of this mixed waste, which was done under a Resource Conservation and Recovery Act treatability study. Waste forms included liquids, sludges, and solids, and treatment techniques included the use of conventional Portland cement and sulphur polymer cement (SPC). A total of 113 monoliths were made under the experimental design matrix for this study; 8 of these were ``blank`` monoliths (contained no waste). Thus, 105 monoliths were used to solidify 21.6 kg of mixed waste; 92 were made with Portland cement systems, and 13 were made with SPC. Recipes for all monoliths are given, and suggested recipes (as based on the minimized leaching of toxic components) are summarized. In most cases, the results presented herein indicate that solidification was successful in immobilizing toxic metals, thereby transforming low-level mixed waste into low-level nonhazardous waste. The ultimate goal of this project is to use appropriate solidification techniques, as described in the literature, to transform low-level mixed waste to low-level nonhazardous waste by satisfying pertinent disposal requirements for this waste. Disposal requirements consider the toxicity characteristic leaching procedure tests, a free liquids test, and radiological analyses. This work is meaningful in that it will provide a basis for the disposal of waste that is currently categorized as LDR low-level mixed waste.

  15. Treatability study for the bench-scale solidification of nonincinerable LDR low-level mixed waste

    Energy Technology Data Exchange (ETDEWEB)

    Gering, K. L.

    1993-01-01

    The focus of this report is the solidification of nonincinerable, land disposal restricted (LDR) low-level mixed waste generated at the Idaho National Engineering Laboratory. Benchscale solidification was performed on samples of this mixed waste, which was done under a Resource Conservation and Recovery Act treatability study. Waste forms included liquids, sludges, and solids, and treatment techniques included the use of conventional Portland cement and sulphur polymer cement (SPC). A total of 113 monoliths were made under the experimental design matrix for this study; 8 of these were blank'' monoliths (contained no waste). Thus, 105 monoliths were used to solidify 21.6 kg of mixed waste; 92 were made with Portland cement systems, and 13 were made with SPC. Recipes for all monoliths are given, and suggested recipes (as based on the minimized leaching of toxic components) are summarized. In most cases, the results presented herein indicate that solidification was successful in immobilizing toxic metals, thereby transforming low-level mixed waste into low-level nonhazardous waste. The ultimate goal of this project is to use appropriate solidification techniques, as described in the literature, to transform low-level mixed waste to low-level nonhazardous waste by satisfying pertinent disposal requirements for this waste. Disposal requirements consider the toxicity characteristic leaching procedure tests, a free liquids test, and radiological analyses. This work is meaningful in that it will provide a basis for the disposal of waste that is currently categorized as LDR low-level mixed waste.

  16. Mesh deployable antenna mechanics testing method

    Science.gov (United States)

    Jiang, Li

    Rapid development in spatial technologies and continuous expansion of astronautics applications require stricter and stricter standards in spatial structure. Deployable space structure as a newly invented structural form is being extensively adopted because of its characteristic (i.e. deployability). Deployable mesh reflector antenna is a kind of common deployable antennas. Its reflector consists in a kind of metal mesh. Its electrical properties are highly dependent on its mechanics parameters (including surface accuracy, angle, and position). Therefore, these mechanics parameters have to be calibrated. This paper presents a mesh antenna mechanics testing method that employs both an electronic theodolite and a laser tracker. The laser tracker is firstly used to measure the shape of radial rib deployable antenna. The measurement data are then fitted to a paraboloid by means of error compensation. Accordingly, the focus and the focal axis of the paraboloid are obtained. The following step is to synchronize the coordinate systems of the electronic theodolite and the measured antenna. Finally, in a microwave anechoic chamber environment, the electromechanical axis is calibrated. Testing results verify the effectiveness of the presented method.

  17. Deployment Repeatability

    Science.gov (United States)

    2016-08-31

    potential future space-based mission through large-scale, ground-based testing. Full-scale deployment testing of two petal segments combined with...capture data for incorporation into larger analysis models. Stability testing of two full-scale composite strongback segments , including in a relevant...errors. The NuSTAR project opted for a metrology and adjustment system, which had many advantages for the project and few disadvantages . Because a

  18. Deployment Repeatability

    Science.gov (United States)

    2016-04-01

    controlled to great precision, but in a Cubesat , there may be no attitude determination at all. Such a Cubesat might treat sun angle and tumbling rates as...could be sensitive to small differences in motor controller timing. In these cases, the analyst might choose to model the entire deployment path, with...knowledge of the material damage model or motor controller timing precision. On the other hand, if many repeated and environmentally representative

  19. Deployable centralizers

    Energy Technology Data Exchange (ETDEWEB)

    Grubelich, Mark C.; Su, Jiann-Cherng; Knudsen, Steven D.

    2017-02-28

    A centralizer assembly is disclosed that allows for the assembly to be deployed in-situ. The centralizer assembly includes flexible members that can be extended into the well bore in situ by the initiation of a gas generating device. The centralizer assembly can support a large load carrying capability compared to a traditional bow spring with little or no installation drag. Additionally, larger displacements can be produced to centralize an extremely deviated casing.

  20. Deployment Guide

    Science.gov (United States)

    1994-02-01

    family/unit briefings (to include POA/wills/ consumer law /insurance war clauses) - Provide fill-in-blank sheets to send coordinators of pre- deployment...services. 2. SGLI designations and "By Law" implications. 3. Wills for both spouses. 4. Powers of Attorney. 5. Consumer law issues. 1-7 B. Typically...Relief Act JA 261 Real Property Guide JA 262 Wills Guide JA 263 Family Law Guide JA 265 Consumer Law Guide JA 267 Legal Assistance Office Directory

  1. Lamp with a truncated reflector cup

    Science.gov (United States)

    Li, Ming; Allen, Steven C.; Bazydola, Sarah; Ghiu, Camil-Daniel

    2013-10-15

    A lamp assembly, and method for making same. The lamp assembly includes first and second truncated reflector cups. The lamp assembly also includes at least one base plate disposed between the first and second truncated reflector cups, and a light engine disposed on a top surface of the at least one base plate. The light engine is configured to emit light to be reflected by one of the first and second truncated reflector cups.

  2. Investigations of Bragg reflectors in nanowire lasers

    CERN Document Server

    Svendsen, Guro Kristin; Skaar, Johannes

    2011-01-01

    The reflectivity of various Bragg reflectors in connection to waveguide structures, including nanowires, has been investigated using modal reflection and transmission matrices. A semi-analytical model was applied yielding increased understanding of the diffraction effects present in such gratings. Planar waveguides and nanowire lasers are considered in particular. Two geometries are compared; Bragg reflectors within the waveguides are shown to have significant advantages compared to Bragg reflectors in the substrate, when diffraction effects are significant.

  3. Springback-Compensated, Submillimeter Reflectors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Inconsistent radius of curvature of replicated, composite reflector panels limit application of composites to large, segmented telescope apertures. This project...

  4. Solar thermal collectors using planar reflector

    Science.gov (United States)

    Espy, P. N.

    1978-01-01

    Specular reflectors have been used successfully with flat-plate collectors to achieve exceptionally high operating temperatures and high delivered energy per unit collector area. Optimal orientation of collectors and reflectors can result in even higher performance with an improved relationship between energy demand and supply. This paper reports on a study providing first order optimization of collector-reflector arrays in which single- and multiple-faceted reflectors in fixed or singly adjustable configurations provide delivered energy maxima in either summer or winter.

  5. Cherenkov radiation oscillator without reflectors

    Science.gov (United States)

    Li, D.; Wang, Y.; Hangyo, M.; Wei, Y.; Yang, Z.; Miyamoto, S.

    2014-05-01

    This Letter presents a Cherenkov radiation oscillator with an electron beam travelling over a finitely thick plate made of negative-index materials. In such a scheme, the external reflectors required in the traditional Cherenkov oscillators are not necessary, since the electromagnetic energy flows backward in the negative-index materials, leading to inherent feedback. We theoretically analyzed the interaction between the electron beam and the electromagnetic wave, and worked out the growth rate and start current through numerical calculations. With the help of particle-in-cell simulation, the theoretical predictions are well demonstrated.

  6. A nonlinear equivalent circuit method for analysis of passive intermodulation of mesh reflectors

    Directory of Open Access Journals (Sweden)

    Jiang Jie

    2014-08-01

    Full Text Available Passive intermodulation (PIM has gradually become a serious electromagnetic interference due to the development of high-power and high-sensitivity RF/microwave communication systems, especially large deployable mesh reflector antennas. This paper proposes a field-circuit coupling method to analyze the PIM level of mesh reflectors. With the existence of many metal–metal (MM contacts in mesh reflectors, the contact nonlinearity becomes the main reason for PIM generation. To analyze these potential PIM sources, an equivalent circuit model including nonlinear components is constructed to model a single MM contact so that the transient current through the MM contact point induced by incident electromagnetic waves can be calculated. Taking the electric current as a new electromagnetic wave source, the far-field scattering can be obtained by the use of electromagnetic numerical methods or the communication link method. Finally, a comparison between simulation and experimental results is illustrated to verify the validity of the proposed method.

  7. Monolithic resonant optical reflector laser diodes

    Science.gov (United States)

    Hirata, T.; Suehiro, M.; Maeda, M.; Hihara, M.; Hosomatsu, H.

    1991-10-01

    The first monolithic resonant optical reflector laser diode that has a waveguide directional coupler and two DBR reflectors integrated by compositional disordering of quantum-well heterostructures is described. A linewidth of 440 kHz was obtained, and this value is expected to be greatly decreased by reducing the propagation loss in the integrated waveguide.

  8. Shaped cassegrain reflector antenna. [design equations

    Science.gov (United States)

    Rao, B. L. J.

    1973-01-01

    Design equations are developed to compute the reflector surfaces required to produce uniform illumination on the main reflector of a cassegrain system when the feed pattern is specified. The final equations are somewhat simple and straightforward to solve (using a computer) compared to the ones which exist already in the literature. Step by step procedure for solving the design equations is discussed in detail.

  9. PENGARUH TINGKAT LOAN TO DEPOSIT RATIO (LDR TERHADAP PROFITABILITAS PADA PT BANK X (PERIODE TAHUN 2008-2012

    Directory of Open Access Journals (Sweden)

    Yani Restiani Widjaja

    2016-03-01

    Full Text Available Abstract - Bank is a financial institution that serves as a financial intermediary which means collecting funds from the public and distribute it back to the community in the form of loans. The purpose of this study was to determine whether there is a significant influence and how much influence the Loan to Deposit Ratio (LDR to Bank Profitability expressed by Return on Assets (ROA.The method used in this research is deskriptife with the survey approach. While to analyze the data, used a quantitative approach, namely the technique of correlation analysis and simple linear regression analysis as a tool for the calculation.From the research, the regression equation is Y = 0.083 +0.706 X.   Keywords: Loan to Deposit Ratio (LDR, Bank Profitability, Return on Asset (ROA   Abstrak - Bank adalah lembaga keuangan yang berfungsi sebagai financial intermediary yang berarti menghimpun dana dari masyarakat dan menyalurkannya kembali kepada masyarakat ke dalam bentuk pinjaman.Tujuan dilakukannya penelitian ini adalah untuk mengetahui apakah terdapat pengaruh yang signifikan dan seberapa besar pengaruh Loan to Deposit Ratio (LDR terhadap Profitabilitas Bank yang dinyatakan dengan Return on Asset (ROA. Metode penelitian yang digunakan pada penelitian ini adalah metode Deskriptif dengan pendekatan survei. Sementara untuk menganalisis data, digunakan pendekatan kuantitatif, yaitu dengan teknik analisis korelasi dan analisis regresi linier sederhana sebagai alat bantu perhitungannya.  Dari hasil penelitian,diperoleh persamaan regresi yaitu Y= 0,083+0,706 X.   Kata kunci : Loan to Deposit Ratio (LDR, Profitabilitas Bank,Return on Asset (ROA

  10. Calculation of thermal noise in grating reflectors

    CERN Document Server

    Heinert, Daniel; Friedrich, Daniel; Hild, Stefan; Kley, Ernst-Bernhard; Leavey, Sean; Martin, Iain W; Nawrodt, Ronny; Tünnermann, Andreas; Vyatchanin, Sergey P; Yamamoto, Kazuhiro

    2013-01-01

    Grating reflectors have been repeatedly discussed to improve the noise performance of metrological applications due to the reduction or absence of any coating material. So far, however, no quantitative estimate on the thermal noise of these reflective structures exists. In this work we present a theoretical calculation of a grating reflector's noise. We further apply it to a proposed 3rd generation gravitational wave detector. Depending on the grating geometry, the grating material and the temperature we obtain a thermal noise decrease by up to a factor of ten compared to conventional dielectric mirrors. Thus the use of grating reflectors can substantially improve the noise performance in metrological applications.

  11. A Revolute Joint With Linear Load-Displacement Response for Precision Deployable Structures

    Science.gov (United States)

    Lake, Mark S.; Warren, Peter A.; Peterson, Lee D.

    1996-01-01

    NASA Langley Research center is developing key structures and mechanisms technologies for micron-accuracy, in-space deployment of future space instruments. Achieving micron-accuracy deployment requires significant advancements in deployment mechanism design such as the revolute joint presented herein. The joint presented herein exhibits a load-cycling response that is essentially linear with less than two percent hysteresis, and the joint rotates with less than one in.-oz. of resistance. A prototype reflector metering truss incorporating the joint exhibits only a few microns of kinematic error under repeated deployment and impulse loading. No other mechanically deployable structure found in literature has been demonstrated to be this kinematically accurate.

  12. Perfect Multi-Channel Flat Reflectors

    CERN Document Server

    Asadchy, V S; Elsakka, A; Albooyeh, M; Tretyakov, S A

    2016-01-01

    Recent advances in engineered gradient metasurfaces have enabled unprecedented opportunities for light manipulation using optically thin sheets, such as anomalous refraction, reflection, or focusing of an incident beam. Here we introduce a concept of multi-channel functional metasurfaces, which are able to control incoming and outgoing waves in a number of propagation directions or polarization states simultaneously and independently. In particular, we reveal a possibility to create perfect multi-channel reflectors. Under the assumption of reciprocity and energy conservation, we find that there exist three fundamental classes of multi-channel mirrors. Together they form a basis of all possible reflection functionalities achievable with flat periodically modulated reflectors. To demonstrate the potential of the introduced concept, we design and experimentally test one of the basis multi-channel reflectors, confirming the desired multi-channel response. Furthermore, by extending the concept to reflectors suppor...

  13. Efficient Wave Energy Amplification with Wave Reflectors

    DEFF Research Database (Denmark)

    Kramer, Morten Mejlhede; Frigaard, Peter Bak

    2002-01-01

    Wave Energy Converters (WEC's) extract wave energy from a limited area, often a single point or line even though the wave energy is generally spread out along the wave crest. By the use of wave reflectors (reflecting walls) the wave energy is effectively focused and increased to approximately 130......-140%. In the paper a procedure for calculating the efficiency and optimizing the geometry of wave reflectors are described, this by use of a 3D boundary element method. The calculations are verified by laboratory experiments and a very good agreement is found. The paper gives estimates of possible power benifit...... for different geometries of the wave reflectors and optimal geometrical design parameters are specified. On this basis inventors of WEC's can evaluate whether a specific WEC possible could benefit from wave reflectors....

  14. Flexible-Robotic Reflector for Aerospace Applications

    Directory of Open Access Journals (Sweden)

    Nir Shvalb

    2015-01-01

    Full Text Available Existing dish based antennas tend to have geometric morphologic distortion in the surface due to drastic thermal changes common in the space environment. In this paper we present a new concept for a dynamic antenna specially designed for communication satellites. The suggested flexible-robotic antenna is based on a dual-reflector structure, where the subreflector has a complex surface shaping robotic mechanism allowing it to fix most of the morphologic errors in the main reflector. We have implemented a set of searching algorithms allowing the hyper redundant robotic subreflector to adapt its surface to the morphologic distortions in the main reflector. The suggested new antenna was constructed and tested in an RF room in which it was able to fix the loss caused by distortion in the main reflector to the original gain in less than an hour.

  15. The selection of artificial corner reflectors based on RCS analysis

    Science.gov (United States)

    Li, Chengfan; Yin, Jingyuan; Zhao, Junjuan; Zhang, Guifang; Shan, Xinjian

    2012-02-01

    Artificial corner reflectors (ACRs) are widely applicable in monitoring terrain change via interferometric synthetic aperture radar (InSAR) remote sensing techniques. Many different types are available. The choice of the most appropriate ones has recently attracted scholarly attentions. Based on physical optics methods, via calculating the radar cross section (RCS) values (the higher the value, the better the detectability), the current study tested three ACRs, i.e., triangular pyramidal, rectangular pyramidal and square trihedral ACRs. Our calculation suggests that the square trihedral ACR produces the largest RCS but least tolerance towards incident radar ray's deviation from optimal angle. The triangular pyramidal trihedral ACR is the most geometrically stable ACR, and has the highest tolerance towards incident radar ray's deviation. Its RCS values, however, are the least of the three. Due to the high cost of deploying ACRs in the fields, the physical optics method seems to provide a viable way to choose appropriate ACRs.

  16. Handbook of reflector antennas and feed systems v.3 applications of reflectors

    CERN Document Server

    Rao, Sudhakar; Sharma, Satish K

    2013-01-01

    This is the first truly comprehensive and most up-to-date handbook available on modern reflector antennas and feed sources for diversified space and ground applications. There has never been such an all-encompassing reflector handbook in print, and no currently available title offers coverage of such recent research developments. The Handbook consists of three volumes. Volume III focuses on the range of reflector antenna applications, including space, terrestrial, and radar. The intent of this book volume is to provide practical applications and design information on reflector antennas used fo

  17. Easily Assembled Reflector for Solar Concentrators

    Science.gov (United States)

    Bouquet, F. L.; Hasegawa, T.

    1982-01-01

    Reflectors for concentrating solar collectors are assembled quickly and inexpensively by method that employs precontoured supports, plastic film, and adhesive to form a segmented glass mirror. New method is self-focusing, and does not require skilled labor at any stage. Contoured ribs support film and mirror segments of reflector. Nine mirror segments are bonded to sheet. Combined mirror surface closely approximates a spherical surface with a radius of curvature of 36 inches (0.91 m).

  18. Solar central receiver heliostat reflector assembly

    Science.gov (United States)

    Horton, Richard H.; Zdeb, John J.

    1980-01-01

    A heliostat reflector assembly for a solar central receiver system comprises a light-weight, readily assemblable frame which supports a sheet of stretchable reflective material and includes mechanism for selectively applying tension to and positioning the sheet to stretch it to optical flatness. The frame is mounted on and supported by a pipe pedestal assembly that, in turn, is installed in the ground. The frame is controllably driven in a predetermined way by a light-weight drive system so as to be angularly adjustable in both elevation and azimuth to track the sun and efficiently continuously reflect the sun's rays to a focal zone, i.e. central receiver, which forms part of a solar energy utilization system, such as a solar energy fueled electrical power generation system. The frame may include a built-in system for testing for optical flatness of the reflector. The preferable geometric configuration of the reflector is octagonal; however, it may be other shapes, such as hexagonal, pentagonal or square. Several different embodiments of means for tensioning and positioning the reflector to achieve optical flatness are disclosed. The reflector assembly is based on the stretch frame concept which provides an extremely light-weight, simple, low-cost reflector assembly that may be driven for positioning and tracking by a light-weight, inexpensive drive system.

  19. Using LDR as Sensing Element for an External Fuzzy Controller Applied in Photovoltaic Pumping Systems with Variable-Speed Drives.

    Science.gov (United States)

    Maranhão, Geraldo Neves De A; Brito, Alaan Ubaiara; Leal, Anderson Marques; Fonseca, Jéssica Kelly Silva; Macêdo, Wilson Negrão

    2015-09-22

    In the present paper, a fuzzy controller applied to a Variable-Speed Drive (VSD) for use in Photovoltaic Pumping Systems (PVPS) is proposed. The fuzzy logic system (FLS) used is embedded in a microcontroller and corresponds to a proportional-derivative controller. A Light-Dependent Resistor (LDR) is used to measure, approximately, the irradiance incident on the PV array. Experimental tests are executed using an Arduino board. The experimental results show that the fuzzy controller is capable of operating the system continuously throughout the day and controlling the direct current (DC) voltage level in the VSD with a good performance.

  20. Using LDR as Sensing Element for an External Fuzzy Controller Applied in Photovoltaic Pumping Systems with Variable-Speed Drives

    Directory of Open Access Journals (Sweden)

    Geraldo Neves De A. Maranhão

    2015-09-01

    Full Text Available In the present paper, a fuzzy controller applied to a Variable-Speed Drive (VSD for use in Photovoltaic Pumping Systems (PVPS is proposed. The fuzzy logic system (FLS used is embedded in a microcontroller and corresponds to a proportional-derivative controller. A Light-Dependent Resistor (LDR is used to measure, approximately, the irradiance incident on the PV array. Experimental tests are executed using an Arduino board. The experimental results show that the fuzzy controller is capable of operating the system continuously throughout the day and controlling the direct current (DC voltage level in the VSD with a good performance.

  1. New principle for unpolarized wideband reflectors

    CERN Document Server

    Niraula, Manoj

    2016-01-01

    There is immense scientific interest in the properties of resonant thin films embroidered with periodic nanoscale features. This device class possesses considerable innovation potential. Accordingly, we report unpolarized broadband reflectors enabled by a serial arrangement of a pair of polarized subwavelength gratings. Optimized with numerical methods, our elemental gratings consist of a partially-etched crystalline-silicon film on a quartz substrate. The resulting reflectors exhibit extremely wide spectral reflection bands in one polarization. By arranging two such reflectors sequentially with orthogonal periodicities, there results an unpolarized spectral band that exceeds those of the individual polarized bands. In the experiments reported herein, we achieve zero-order reflectance exceeding 97% under unpolarized light incidence over a 500-nm-wide wavelength band in the near-infrared domain. Moreover, the resonant unpolarized broadband accommodates an ultra-high-reflection band spanning ~85 nm and exceedin...

  2. Broadband Multilayered Array Antenna with EBG Reflector

    Directory of Open Access Journals (Sweden)

    P. Chen

    2013-01-01

    Full Text Available Most broadband microstrip antennae are implemented in the form of slot structure or laminate structure. The impedance bandwidth is broadened, but meanwhile, the sidelobe of the directivity pattern and backlobe level are enlarged. A broadband stacked slot coupling microstrip antenna array with EBG structure reflector is proposed. Test results indicate that the proposed reflector structure can effectively improve the directivity pattern of stacked antenna and aperture coupled antenna, promote the front-to-back ratio, and reduce the thickness of the antenna. Therefore, it is more suitable to be applied as an airborne antenna.

  3. Surface roughness estimation of a parabolic reflector

    CERN Document Server

    Casco, Nicolás A

    2010-01-01

    Random surface deviations in a reflector antenna reduce the aperture efficiency. This communication presents a method for estimating the mean surface deviation of a parabolic reflector from a set of measured points. The proposed method takes into account systematic measurement errors, such as the offset between the origin of reference frame and the vertex of the surface, and the misalignment between the surface rotation axis and the measurement axis. The results will be applied to perform corrections to the surface of one of the 30 m diameter radiotelescopes at the Instituto Argentino de Radioastronom\\'ia (IAR).

  4. Handbook of reflector antennas and feed systems v.1 theory and design of reflectors

    CERN Document Server

    Sharma, Satish K; Shafai, Lotfollah

    2013-01-01

    This is the first truly comprehensive and most up-to-date handbook available on modern reflector antennas and feed sources for diversified space and ground applications. There has never been such an all-encompassing reflector handbook in print, and no currently available title offers coverage of such recent research developments. The Handbook consists of three volumes. Volume I provides a unique combination of theoretical underpinnings with design considerations and techniques. The need for knowledge in reflector antennas has grown steadily over the last two decades due to increased use in spa

  5. Sistem Pengendali Peralatan Elektronik dalam Rumah secara Otomatis Menggunakan Sensor PIR, Sensor LM35, dan Sensor LDR

    Directory of Open Access Journals (Sweden)

    Eka Desyantoro

    2015-08-01

    Full Text Available Listrik merupakan hal yang sangat penting di kehidupan kita. Setiap pekerjaan kita pasti dibantu dengan adanya listrik. Mulai dari penerangan hingga pengaturan suhu ruangan pun semuanya dibantu oleh listrik. Ketergantungan manusia terhadap listrik ini menimbulkan kebiasaan buruk. Banyak orang yang terkadang membiarkan suatu peralatan elektronik hidup pada saat tidak dibutuhkan. Terjadi suatu permasalahan untuk menciptakan suatu desain sistem embedded untuk mengendalikan peralatan elektronik dalam rumah secara otomatis. Makalah ini membahas tentang perancangan sistem pengendali peralatan elektronik dalam rumah secara otomatis. Sistem terdiri dari sensor PIR yang berfungsi untuk mendeteksi objek bergerak (manusia, sensor LM35 yang berfungsi untuk mendeteksi suhu, dan sensor LDR berfungsi sebagai sensor cahaya. Mikrokontroller ATMega16 sebagai pengendali jalannya sistem dari pembacaan sensor, menampilkan data sensor pada LCD dan mengatur kontak relay untuk menghidup dan mematikan listrik. Sistem pengendali peralatan elektronik dalam rumah secara otomatis menunjukan sensor LDR dapat membedakan gelap dan terang, sensor suhu LM35 dapat mendeteksi suhu dalam ruangan dengan toleransi kesalahan pembacaan kurang lebih 2o Celcius, dan sensor PIR dapat mendeteksi pergerakan manusia sejauh 5 meter.

  6. The geometrical theory of diffraction for axially symmetric reflectors

    DEFF Research Database (Denmark)

    Rusch, W.; Sørensen, O.

    1975-01-01

    The geometrical theory of diffraction (GTD) (cf. [1], for example) may be applied advantageously to many axially symmetric reflector antenna geometries. The material in this communication presents analytical, computational, and experimental results for commonly encountered reflector geometries...

  7. Synchronously Deployable Truss Structures

    Science.gov (United States)

    Rhodes, M. D.; Hedgepeth, J. M.

    1986-01-01

    Structure lightweight, readily deployed, and has reliable joints. New truss concept, designated as "pac truss," developed. Features easy deployment without need for complex mechanisms. Structures of this type deployed in free flight by controlled release of stored energy in torsional springs at selected hinges located throughout structure. Double-folding technique used in beam model applicable to flat planar trusses, allowing structures of large expanse to fold into compact packages and be deployed for space-platform applications.

  8. Transformable reflector structure with V-folding rods

    Science.gov (United States)

    Tserodze, Sh.; Prowald, J. Santiago; Gogilashvili, V.; Chkhikvadze, K.

    2016-12-01

    A new design of space deployable reflector is presented. In particular, we consider closed-chain system (with central network), which as a result of transformation reaches the conical shape. In conformity with the technical specifications, individual parts of the system perform the simultaneous motion in the radial and axial directions. The main motion of the system produced by geometric constraints is studied, i.e., we consider the degree of structural motion. Parametric degrees of freedom caused by technological errors, modes of motion, types of load or deployment velocity are not taken into consideration at this stage. A peculiar feature of the deployable structure presented in the paper is that, as compared with analogous structures, for connecting the sections with one another there is no need of using synchronization devices in both—upper and lower kinematic chains simultaneously. This structural mechanism is a differential lever mechanism, the driving elements of which enable us to obtain the desired law of motion of every characteristic link. The kinematic model represents the whole system. Therefore, we can construct the function of position of the lever mechanism and also the kinematic functions of transmission. For the preliminary investigation of the structure and making possible changes in it, two mathematical models have been constructed by means of the ANSYS software using the Ansys Parametric Design Language. The degrees of freedom of the hinges are simulated in local coordinate systems and are as much as possible approximated to the real model. Calculations are performed for various kinds of loads and appropriate results are obtained.

  9. Solar array deployment mechanism

    Science.gov (United States)

    Calassa, Mark C.; Kackley, Russell

    1995-05-01

    This paper describes a Solar Array Deployment Mechanism (SADM) used to deploy a rigid solar array panel on a commercial spacecraft. The application required a deployment mechanism design that was not only lightweight, but also could be produced and installed at the lowest possible cost. This paper covers design, test, and analysis of a mechanism that meets these requirements.

  10. Vertical reflector for bifacial PV-panels

    DEFF Research Database (Denmark)

    Jakobsen, Michael Linde; Thorsteinsson, Sune; Poulsen, Peter Behrensdorff;

    2016-01-01

    Bifacial solar modules offer an interesting price/performance ratio, and much work has been focused on directing the ground albedo to the back of the solar cells. In this work we design and develop a reflector for a vertical bifacial panel, with the objective to optimize the energy harvest...

  11. Hybrid grating reflectors: Origin of ultrabroad stopband

    DEFF Research Database (Denmark)

    Park, Gyeong Cheol; Taghizadeh, Alireza; Chung, Il-Sug

    2016-01-01

    Hybrid grating (HG) reflectors with a high-refractive-index cap layer added onto a high contrast grating (HCG) provide a high reflectance close to 100% over a broader wavelength range than HCGs. The combination of a cap layer and a grating layer brings a strong Fabry-Perot (FP) resonance as well...

  12. Vertical reflector for bifacial PV-panels

    DEFF Research Database (Denmark)

    Jakobsen, Michael Linde; Thorsteinsson, Sune; Poulsen, Peter Behrensdorff

    2016-01-01

    Bifacial solar modules offer an interesting price/performance ratio, and much work has been focused on directing the ground albedo to the back of the solar cells. In this work we design and develop a reflector for a vertical bifacial panel, with the objective to optimize the energy harvest...

  13. Reflector Surface Modelling : A European Collaboration

    NARCIS (Netherlands)

    Albani, M; Balling, P.; Ettorre, M.; Gerini, G.; Maci, S.; Pontoppidan, K.; Sipus, Z.; Sjöberg, D.; Vecchi, G.; Vipiana, F.

    2007-01-01

    The topic of this paper is the work carried out in Work Package 2.3-2 of the EU network ACE. This work package is concerned with the modelling of the surfaces of modern reflector antennas. In particular the problems associated with homogenisation of periodic structures are described together with an

  14. Development of NRU reflector wall inspection system

    Energy Technology Data Exchange (ETDEWEB)

    Lumsden, R.H.; Luloff, B.V.; Zahn, N.; Simpson, N., E-mail: lumsdenr@aecl.ca [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)

    2013-06-15

    In 2009 May, the National Research Universal (NRU) calandria leaked. During the next year, the calandria was inspected with six new Non-Destructive Evaluation (NDE) techniques to determine the extent of the corrosion, repaired, and finally the repair was inspected with four additional new NDE techniques before the reactor was returned to service. The calandria is surrounded by a light-water reflector vessel fabricated from the same material as the calandria vessel. Concerns that the same corrosion mechanism had damaged the reflector vessel led to the development of a system to inspect the full circumference of the reflector wall for corrosion damage. The inspection region could only be accessed through 64 mm diameter ports, was 10 m below the port, and had to be inspected from the corroded surface. The ultrasonic technique was designed to produce a closely spaced wall thickness (WT) grid over an area of approximately 5 m2 on the corroded surface using a very small probe holder. This paper describes the Reflector Wall Inspection (RWI) development project and the system that resulted. (author)

  15. Multimode Analysis of Bragg Reflectors for Cyclotron Maser Applications

    Science.gov (United States)

    1991-02-16

    exponentially with distance in the reflector. The spatial dependance of the TMI I mode is oscillatory. Figure 3 shows the frequency dependence of the...mode reflector for a CARM oscillator resonator. Figure 4 shows the frequency dependance of the reflection and mode conversion in the reflector. In order

  16. A New Reflector Antenna Based on the Fresnel Principle

    Institute of Scientific and Technical Information of China (English)

    DUHui-ping

    2001-01-01

    A new type of reflector antenne is proposed, which applies the 1-D Fresnel zone phase correction to the classical parabolic cylindrical reflector, providing an alternative to the dval parabolic cylindrical ones discussed by Sanad and Shafai[1].The focusing characteristics of the new reflector are analyzed by physical optics method, and numerical results are illustrated to evaluate its applicability.

  17. A New Reflector Antenna Based on the Fresnel Principle

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A new type of reflector antenne is proposed, which applies the 1-D Fresnel zone phase correction to the classical parabolic cylindrical reflector, providing an alternative to the dual parabolic cylindrical ones discussed by Sanad and Shafai[1]. The focusing characteristics of the new reflector are analyzed by physical optics method, and numerical results are illustrated to evaluate its applicability.

  18. Mastering Windows 7 Deployment

    CERN Document Server

    Finn, Aidan; van Surksum, Kenneth

    2011-01-01

    Get professional-level instruction on Windows 7 deployment tools Enterprise-level operating system deployment is challenging and requires knowledge of specific tools. It is expected that Windows 7 will be extensively deployed in businesses worldwide. This comprehensive Sybex guide provides thorough coverage of the Microsoft deployment tools that were specifically created for Windows 7, preparing system administrators, MIS professionals, and corporate programmers to tackle the task effectively.Companies worldwide are expected to deploy Windows 7 as their enterprise operating system; system admi

  19. APPLICATION OF QUATERNIONS FOR REFLECTOR PARAMETER

    Directory of Open Access Journals (Sweden)

    I. A. Konyakhin

    2016-09-01

    Full Text Available Subject of Research. The paper deals with application of quaternions for optimization of reflector parameters at autocollimation measurements in comparison with a matrix method. Computer-based results on the quaternionic models are presented that have given the possibility to determine conditions of measurement error reduction in view of apriori information on the rotation axis position. The practical synthesis technique for tetrahedron reflector parameters using found ratios is considered. Method. Originally, received conditions for reduction of autocollimation system measurement error are determined with the use of a matrix method for definition of an angular object position as a set of three equivalent consecutive turns about coordinate axes. At realization of these conditions the numerous recalculation of orientation parameters between various systems of coordinates is necessary that increases complexity and reduces resulting accuracy of autocollimation system at practical measurements. The method of quaternions gives the possibility to analyze the change of an absolute angular position in space, thus, there are conditions of accuracy increase regardless of the used systems of coordinates. Main Results. Researches on the mathematical model have shown, that the orthogonal arrangement of two basic constant directions for autocollimator tetrahedron reflector is optimal with respect to criterion of measurement error reduction at bisection arrangement of actual turn axis against them. Practical Relevance. On the basis of the found ratios between tetrahedron reflector angles and angles of its initial orientation parameters we have developed a practical method of reflector synthesis for autocollimation measurements in case of apriori information on an actual turn axis at monitoring measurements of the shaft or pipelines deformations.

  20. SMA applications in an innovative multishot deployment mechanism

    Science.gov (United States)

    Stella, D.; Pedrazzoli, G.; Secci, G.; Portelli, C.

    1991-01-01

    An innovative Deployment and Retraction hinge Mechanism (DARM) in the frame of a technological program is examined. The mechanism includes two restraint/release devices, which enable it to be stable in its stowed or deployed position while sustaining all associated loads, and to carry its payload by remote command. The main characteristics of the DARM are as follows: deployment and retraction movements are spring actuated; the available amount of functional sequences is almost unlimited; and no use of electrical motors is made. These features were accomplished by: the application of a special kinematic scheme to the mechanical connection between the spring motor and the swivel head arm; and the use of shape memory alloys (SMA) actuators for both release and spring recharge functions. DARM is thus a mechanism which can find many applications in the general space scenario of in-orbit maintenance and servicing. In such a frame, the DARM typical concept, which has a design close to very simple one-shot deployment mechanisms, has a good chance to replace existing analog machines. Potential items that could be moved by DARM are: booms for satellite instruments; antenna reflector tips; entire antenna reflectors; and solar panels.

  1. Homology Parameters for Large Axisymmetric Shaped Dual-Reflector Antennas

    Science.gov (United States)

    Ban, You; Duan, Baoyan; Wang, Congsi; Wang, Wei; Feng, Shufei; Xiang, Binbin

    2017-05-01

    We extend the concept of best-fitting paraboloids for large single and dual reflectors with conic-section surfaces to best-fit shaped surface for large dual reflectors shaped for uniform amplitude distribution. The point focus of the paraboloidal main reflector is replaced by focal lines for the main reflector and the primary subreflector focus, whereas the secondary subreflector point focus at the feed is kept. The reflector surfaces are shaped, and all rays from the main-reflector aperture to the feed meet an equal-path-length condition. This condition may be represented by a set of "homology parameters" determined by a least-squares method. Finally, we calculate the homology parameters and the root mean square of surface errors for an 8-m dual-reflector system including gravity effects for the antenna pointed toward zenith and the horizon.

  2. Silicon reflectors for external cavity lasers based on ring resonators

    Science.gov (United States)

    Wang, Chao; Li, Xia; Jin, Hao; Yu, Hui; Yang, Jianyi; Jiang, Xiaoqing

    2017-01-01

    We propose and experimentally investigate types of silicon ring reflectors on Silicon-On-Insulator (SOI) platform. These reflectors are used for realizing the silicon hybrid external cavity lasers. A suspended edge coupler is used to connect the reflective semiconductor optical amplifier (RSOA) chip and the reflectors. The properties of the reflectors and the hybrid external cavity lasers with these reflectors are illustrated. The experimental results show that all of those reflectors have a high reflectivity and the highest reflectivity can up to be 95%. The lowest insertion loss can be as low as 0.4 dB. The output power of the hybrid external cavity lasers with these reflectors can reach mW magnitude and the highest output power is 6.1 mW. Over 30 dB side mode suppression ratio is obtained.

  3. A Multiplex PCR/LDR Assay for Simultaneous Detection and Identification of the NIAID Category B Bacterial Food and Water-borne Pathogens

    Science.gov (United States)

    Rundell, Mark S.; Pingle, Maneesh; Das, Sanchita; Hussain, Aashiq; Ocheretina, Oksana; Charles, Macarthur; Larone, Davise H.; Spitzer, Eric D.; Golightly, Linnie; Barany, Francis

    2014-01-01

    Enteric pathogens that cause gastroenteritis remain a major global health concern. The goal of this study was to develop a multiplex PCR/LDR assay for the detection of all NIAID category B bacterial food and water-borne pathogens directly from stool specimens. To validate the PCR/LDR assay, clinical isolates of Campylobacter spp., Vibrio spp., Shigella spp., Salmonella spp., Listeria monocytogenes, Yersinia enterocolitica, and diarrheagenic Escherichia coli were tested. The sensitivity and specificity of the assay was assessed using a large number of seeded culture-negative stool specimens and a smaller set of clinical specimens from Haiti. The overall sensitivity ranged from 91 to 100% (median 100%) depending on the species. For the majority of organisms the sensitivity was 100%. The overall specificity based on initial testing ranged from 98% to 100% depending on the species. After additional testing of discordant samples the lowest specificity was 99.4%. PCR/LDR detected additional category B agents (particularly diarrheagenic E. coli) in 11/40 specimens from Haiti that were culture-positive for V. cholerae and in approximately 1% of routine culture-negative stool specimens from a hospital in New York. This study demonstrated the ability of the PCR/LDR assay to detect a large comprehensive panel of category B enteric bacterial pathogens as well as mixed infections. This type of assay has the potential to provide earlier warnings of possible public health threats and more accurate surveillance of food and water-borne pathogens. PMID:24709368

  4. The DESDynI Synthetic Aperture Radar Array-Fed Reflector Antenna

    Science.gov (United States)

    Chamberlain, Neil; Ghaemi, Hirad; Giersch, Louis; Harcke, Leif; Hodges, Richard; Hoffman, James; Johnson, William; Jordan, Rolando; Khayatian, Behrouz; Rosen, Paul; Sadowy, Gregory; Shaffer, Scott; Shen, Yuhsyen; Veilleux, Louise; Wu, Patrick

    2010-01-01

    DESDynI is a mission being developed by NASA with radar and lidar instruments for Earth-orbit remote sensing. This paper focuses on the design of a largeaperture antenna for the radar instrument. The antenna comprises a deployable reflector antenna and an active switched array of patch elements fed by transmit/ receive modules. The antenna and radar architecture facilitates a new mode of synthetic aperture radar imaging called 'SweepSAR'. A system-level description of the antenna is provided, along with predictions of antenna performance.

  5. Späte Seed-Migration nach LDR-Brachytherapie der Prostata mit I125-Permanentimplantaten

    Directory of Open Access Journals (Sweden)

    Maletzki P

    2015-01-01

    Full Text Available Hintergrund: Nach einer „Lowdose-rate“- (LDR Brachytherapie der Prostata kommt es häufig zu einer Seed-Migration. Trotz mehrerer Arbeiten über eine Seed-Migration in der frühen postoperativen Phase nach Seed-Implantation gibt es bisher nur wenige Daten über eine Seed-Migration mehrere Jahre nach erfolgter Intervention. Unser Ziel war eine Datenerhebung zur Inzidenz, Lokalisation, Symptomatik und therapeutischen Konsequenz einer späten Seed-Migration 3 Jahre nach Seed-Implantation. Methoden: Wir untersuchten retrospektiv 63 unselektionierte Patienten, die mittels transrektaler, Ultraschall-gesteuerter, transperinealer interstitieller LDR-Brachytherapie der Prostata zwischen 2001 und 2010 behandelt wurden. Es wurden hierbei verknüpfte („stranded“ Seeds verwendet. Am ersten Tag nach der Intervention erfolgte eine Symphysenzielaufnahme und 6 Wochen postoperativ eine erneute Symphysenzielaufnahme in Kombination mit einem CT/MRI des Beckens mit Bildfusionstechnik zur dosimetrischen Untersuchung. Die radiologische Spätkontrolle wurde mehr als 3 Jahre postoperativ mittels einer Symphysenzielaufnahme und eines Thorax-Röntgens durchgeführt. Ergebnisse: Mehr als 3 Jahre nach Brachytherapie zeigten 36 der 63 Patienten (57 % einen Seed-Verlust. Die Anzahl fehlender Seeds lag zwischen 1 und 9. Neben einer frühen Seed-Migration zeigte sich eine späte Seed-Migration bei 2 der 36 Patienten (6 % mit Migration in die Lunge, Leber und das kleine Becken. Alle Spätmigrationen waren asymptomatisch und ohne therapeutische Konsequenz. Diskussion: Neben häufig auftretenden Seed-Verlusten scheint eine Seed-Migration mehrere Jahre nach erfolgter Implantation eine seltene Erscheinung zu sein. Langzeitkontrollen mit ergänzenden radiologischen Nachuntersuchungen könnten dennoch hilfreich zur Dokumentation einer relevanten Seed-Migration sein.

  6. Center for Deployment Psychology

    Data.gov (United States)

    Federal Laboratory Consortium — The Center for Deployment Psychology was developed to promote the education of psychologists and other behavioral health specialists about issues pertaining to the...

  7. Deployable geodesic truss structure

    Science.gov (United States)

    Mikulas, Martin M., Jr. (Inventor); Rhodes, Marvin D. (Inventor); Simonton, J. Wayne (Inventor)

    1987-01-01

    A deployable geodesic truss structure which can be deployed from a stowed state to an erected state is described. The truss structure includes a series of bays, each bay having sets of battens connected by longitudinal cross members which give the bay its axial and torsional stiffness. The cross members are hinged at their mid point by a joint so that the cross members are foldable for deployment or collapsing. The bays are deployed and stabilized by actuator means connected between the mid point joints of the cross members. Hinged longerons may be provided to also connect the sets of battens and to collapse for stowing with the rest of the truss structure.

  8. Ellisoidal reflector for measuring otoacoustic emissions

    DEFF Research Database (Denmark)

    Epp, Bastian; Heiskanen, Vesa; Pulkki, Ville Topias

    2016-01-01

    Otoacoustic emissions (OAEs) are low-intensity sounds present in the ear canal, generated by mechanical processing in the cochlear in the inner ear. OAEs provide a noninvasive technique to sense the mechanical processing of sound in the inner ear. These signals are commonly measured by placing......, and especially SOAE at these low frequencies. In addition, blocking of the ear canal changes the impedance of the middle ear, potentially changing the transmission of acoustical energy from the inner ear to the ear canal, hampering the interpretation of the data in terms of normal listening conditions with open...... ear canal. This study presents the design and evaluation of a truncated prolate ellipsoidal reflector in combination with a large-diaphragm low-noise microphone to measure OAEs in the open ear canal of human listeners. The reflector was designed to gain information about BM processing at low...

  9. Simulation of parabolic reflectors for ultraviolet phototherapy

    Science.gov (United States)

    Grimes, David Robert

    2016-08-01

    Ultraviolet (UVR) phototherapy is widely used to treat an array of skin conditions, including psoriasis, eczema and vitiligo. For such interventions, a quantified dose is vital if the treatment is to be both biologically effective and to avoid the detrimental effects of over-dosing. As dose is absorbed at surface level, the orientation of patient site with respect to the UVR lamps modulates effective dose. Previous investigations have modelled this behaviour, and examined the impact of shaped anodized aluminium reflectors typically placed around lamps in phototherapy cabins. These mirrors are effective but tend to yield complex patterns of reflection around the cabin which can result in substantial dose inhomogeneity. There has been some speculation over whether using the reflective property of parabolic mirrors might improve dose delivery or homogeneity through the treatment cabin. In this work, the effects of parabolic mirrors are simulated and compared with standard shaped mirrors. Simulation results strongly suggest that parabolic reflectors reduce total irradiance relative to standard shaped reflectors, and have a negligible impact on dose homogeneity.

  10. Simulation of parabolic reflectors for ultraviolet phototherapy.

    Science.gov (United States)

    Robert Grimes, David

    2016-08-21

    Ultraviolet (UVR) phototherapy is widely used to treat an array of skin conditions, including psoriasis, eczema and vitiligo. For such interventions, a quantified dose is vital if the treatment is to be both biologically effective and to avoid the detrimental effects of over-dosing. As dose is absorbed at surface level, the orientation of patient site with respect to the UVR lamps modulates effective dose. Previous investigations have modelled this behaviour, and examined the impact of shaped anodized aluminium reflectors typically placed around lamps in phototherapy cabins. These mirrors are effective but tend to yield complex patterns of reflection around the cabin which can result in substantial dose inhomogeneity. There has been some speculation over whether using the reflective property of parabolic mirrors might improve dose delivery or homogeneity through the treatment cabin. In this work, the effects of parabolic mirrors are simulated and compared with standard shaped mirrors. Simulation results strongly suggest that parabolic reflectors reduce total irradiance relative to standard shaped reflectors, and have a negligible impact on dose homogeneity.

  11. Deployable antenna kinematics using tensegrity structure design

    Science.gov (United States)

    Knight, Byron Franklin

    With vast changes in spacecraft development over the last decade, a new, cheaper approach was needed for deployable kinematic systems such as parabolic antenna reflectors. Historically, these mesh-surface reflectors have resembled folded umbrellas, with incremental redesigns utilized to save packaging size. These systems are typically over-constrained designs, the assumption being that high reliability necessary for space operations requires this level of conservatism. But with the rapid commercialization of space, smaller launch platforms and satellite buses have demanded much higher efficiency from all space equipment than can be achieved through this incremental approach. This work applies an approach called tensegrity to deployable antenna development. Kenneth Snelson, a student of R. Buckminster Fuller, invented Tensegrity structures in 1948. Such structures use a minimum number of compression members (struts); stability is maintain using tension members (ties). The novelty introduced in this work is that the ties are elastic, allowing the struts to extend or contract, and in this way changing the surface of the antenna. Previously, the University of Florida developed an approach to quantify the stability and motion of parallel manipulators. This approach was applied to deployable, tensegrity, antenna structures. Based on the kinematic analyses for the 3-3 (octahedron) and 4-4 (square anti-prism) structures, the 6-6 (hexagonal anti-prism) analysis was completed which establishes usable structural parameters. The primary objective for this work was to prove the stability of this class of deployable structures, and their potential application to space structures. The secondary objective is to define special motions for tensegrity antennas, to meet the subsystem design requirements, such as addressing multiple antenna-feed locations. This work combines the historical experiences of the artist (Snelson), the mathematician (Ball), and the space systems engineer

  12. Modeling EERE Deployment Programs

    Energy Technology Data Exchange (ETDEWEB)

    Cort, K. A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hostick, D. J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Belzer, D. B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Livingston, O. V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2007-11-01

    This report compiles information and conclusions gathered as part of the “Modeling EERE Deployment Programs” project. The purpose of the project was to identify and characterize the modeling of deployment programs within the EERE Technology Development (TD) programs, address possible improvements to the modeling process, and note gaps in knowledge in which future research is needed.

  13. Surface accuracy and radiation pattern characteristics of mesh deployable refector antennas

    Science.gov (United States)

    Ueno, Miyoshi; Ebisui, Takashi; Okamato, Teruki; Orikasa, Teruaki; Sugimoto, Toshio; Iso, Akio

    To facilitate the growth of mobile satellite communications, both an increase in the Equivalent Isotropically Radiated Power (EIRP) of satellites and improved frequency reuse are required to achiveve compact size, low cost terminal usage, and high channel capacity. High gain and low sidelobe antenna technology are very important for high EIRP and frequency reuse, respectively. These requirements are expected to be met by using a large deployable mesh reflector antenna, which is the key technology for future multibeam moble communications systems. In this paper, surface accruracy and related electrical characteristics are studied using a TETRUS-(Tetra Trigonal Prism Truss) type deployable mesh reflector antenna. Surface accuracy and related electrical characteristics of reflector antennas becaue any distortion of the ideal paraboloidal configuration causes antenna patterns to deteriorate, thereby reducing reflector aperture efficiency and increasing sidelobe and grating lobe levels. The sidelobe and grating lobe characteristics are especially important in frequency reuse. First, we show the problem with the radiation pattern characteristics of TETUS antenna. We then propose a new antenna configuration called the 'HYBRID TETRUS' that improves these characteristics. The mechanical performances of two partial deployable models are also described. Mechanical testing results reveal agreement between the calculated and measured values and high rigidities.

  14. Radar polarimeter measures orientation of calibration corner reflectors

    Science.gov (United States)

    Zebker, Howard A.; Norikane, Lynne

    1987-01-01

    Radar polarimeter signals from a set of trihedral corner reflectors located in the Goldstone Dry Lake in California were analyzed, and three types of scattering behavior were observed: (1) Bragg-like slightly rough surface scattering that represents the background signal from the dry lake, (2) trihedral corner reflector scattering that returns the incident polarization, and (3) two-bounce corner reflector scattering resulting from a particular alignment of a trihedral reflector. A radar calibration approach using trihedral corner reflectors should be designed such that precise alignment of the reflectors is ensured, as three-bounce and two-bounce geometries lead to very different cross sections and hence very different inferred calibration factors.

  15. Properties of wideband resonant reflectors under fully conical light incidence

    Science.gov (United States)

    Ko, Yeong Hwan; Niraula, Manoj; Lee, Kyu Jin; Magnusson, Robert

    2016-03-01

    Applying numerical modeling coupled with experiments, we investigate the properties of wideband resonant reflectors under fully conical light incidence. We show that the wave vectors pertinent to resonant first-order diffraction under fully conical mounting vary less with incident angle than those associated with reflectors in classical mounting. Therefore, as the evanescent diffracted waves drive the leaky modes responsible for the resonance effects, fully-conical mounting imbues reflectors with larger angular tolerance than their classical counterparts. We quantify the angular-spectral performance of representative resonant wideband reflectors in conic and classic mounts by numerical calculations with improved spectra found for fully conic incidence. Moreover, these predictions are verified experimentally for wideband reflectors fashioned in crystalline and amorphous silicon in distinct spectral regions spanning the 1200-1600-nm and 1600-2400-nm spectral bands. These results will be useful in various applications demanding wideband reflectors that are efficient and materially sparse.

  16. APPLICATION OF VISION METROLOGY TO IN-ORBIT MEASUREMENT OF LARGE REFLECTOR ONBOARD COMMUNICATION SATELLITE FOR NEXT GENERATION MOBILE SATELLITE COMMUNICATION

    Directory of Open Access Journals (Sweden)

    M. Akioka

    2016-06-01

    Full Text Available Satellite for next generation mobile satellite communication service with small personal terminal requires onboard antenna with very large aperture reflector larger than twenty meters diameter because small personal terminal with lower power consumption in ground base requires the large onboard reflector with high antenna gain. But, large deployable antenna will deform in orbit because the antenna is not a solid dish but the flexible structure with fine cable and mesh supported by truss. Deformation of reflector shape deteriorate the antenna performance and quality and stability of communication service. However, in case of digital beam forming antenna with phased array can modify the antenna beam performance due to adjustment of excitation amplitude and excitation phase. If we can measure the reflector shape precisely in orbit, beam pattern and antenna performance can be compensated with the updated excitation amplitude and excitation phase parameters optimized for the reflector shape measured every moment. Softbank Corporation and National Institute of Information and Communications Technology has started the project "R&D on dynamic beam control technique for next generation mobile communication satellite" as a contracted research project sponsored by Ministry of Internal Affairs and Communication of Japan. In this topic, one of the problem in vision metrology application is a strong constraints on geometry for camera arrangement on satellite bus with very limited space. On satellite in orbit, we cannot take many images from many different directions as ordinary vision metrology measurement and the available area for camera positioning is quite limited. Feasibility of vision metrology application and general methodology to apply to future mobile satellite communication satellite is to be found. Our approach is as follows: 1 Development of prototyping simulator to evaluate the expected precision for network design in zero order and first order

  17. Application of Vision Metrology to In-Orbit Measurement of Large Reflector Onboard Communication Satellite for Next Generation Mobile Satellite Communication

    Science.gov (United States)

    Akioka, M.; Orikasa, T.; Satoh, M.; Miura, A.; Tsuji, H.; Toyoshima, M.; Fujino, Y.

    2016-06-01

    Satellite for next generation mobile satellite communication service with small personal terminal requires onboard antenna with very large aperture reflector larger than twenty meters diameter because small personal terminal with lower power consumption in ground base requires the large onboard reflector with high antenna gain. But, large deployable antenna will deform in orbit because the antenna is not a solid dish but the flexible structure with fine cable and mesh supported by truss. Deformation of reflector shape deteriorate the antenna performance and quality and stability of communication service. However, in case of digital beam forming antenna with phased array can modify the antenna beam performance due to adjustment of excitation amplitude and excitation phase. If we can measure the reflector shape precisely in orbit, beam pattern and antenna performance can be compensated with the updated excitation amplitude and excitation phase parameters optimized for the reflector shape measured every moment. Softbank Corporation and National Institute of Information and Communications Technology has started the project "R&D on dynamic beam control technique for next generation mobile communication satellite" as a contracted research project sponsored by Ministry of Internal Affairs and Communication of Japan. In this topic, one of the problem in vision metrology application is a strong constraints on geometry for camera arrangement on satellite bus with very limited space. On satellite in orbit, we cannot take many images from many different directions as ordinary vision metrology measurement and the available area for camera positioning is quite limited. Feasibility of vision metrology application and general methodology to apply to future mobile satellite communication satellite is to be found. Our approach is as follows: 1) Development of prototyping simulator to evaluate the expected precision for network design in zero order and first order 2) Trial

  18. Deployable Soft Composite Structures

    Science.gov (United States)

    Wang, Wei; Rodrigue, Hugo; Ahn, Sung-Hoon

    2016-02-01

    Deployable structure composed of smart materials based actuators can reconcile its inherently conflicting requirements of low mass, good shape adaptability, and high load-bearing capability. This work describes the fabrication of deployable structures using smart soft composite actuators combining a soft matrix with variable stiffness properties and hinge-like movement through a rigid skeleton. The hinge actuator has the advantage of being simple to fabricate, inexpensive, lightweight and simple to actuate. This basic actuator can then be used to form modules capable of different types of deformations, which can then be assembled into deployable structures. The design of deployable structures is based on three principles: design of basic hinge actuators, assembly of modules and assembly of modules into large-scale deployable structures. Various deployable structures such as a segmented triangular mast, a planar structure comprised of single-loop hexagonal modules and a ring structure comprised of single-loop quadrilateral modules were designed and fabricated to verify this approach. Finally, a prototype for a deployable mirror was developed by attaching a foldable reflective membrane to the designed ring structure and its functionality was tested by using it to reflect sunlight onto to a small-scale solar panel.

  19. Deployable Soft Composite Structures.

    Science.gov (United States)

    Wang, Wei; Rodrigue, Hugo; Ahn, Sung-Hoon

    2016-02-19

    Deployable structure composed of smart materials based actuators can reconcile its inherently conflicting requirements of low mass, good shape adaptability, and high load-bearing capability. This work describes the fabrication of deployable structures using smart soft composite actuators combining a soft matrix with variable stiffness properties and hinge-like movement through a rigid skeleton. The hinge actuator has the advantage of being simple to fabricate, inexpensive, lightweight and simple to actuate. This basic actuator can then be used to form modules capable of different types of deformations, which can then be assembled into deployable structures. The design of deployable structures is based on three principles: design of basic hinge actuators, assembly of modules and assembly of modules into large-scale deployable structures. Various deployable structures such as a segmented triangular mast, a planar structure comprised of single-loop hexagonal modules and a ring structure comprised of single-loop quadrilateral modules were designed and fabricated to verify this approach. Finally, a prototype for a deployable mirror was developed by attaching a foldable reflective membrane to the designed ring structure and its functionality was tested by using it to reflect sunlight onto to a small-scale solar panel.

  20. Preliminary design of large reflectors with flat facets

    Science.gov (United States)

    Agrawal, P. K.; Anderson, M. S.; Card, M. F.

    1981-01-01

    A concept for approximating curved antenna surfaces using flat facets is discussed. A preliminary design technique for determining the size of the reflector surface facets necessary to meet antenna surface accuracy requirements is presented. A proposed large microwave radiometer satellite (MRS) is selected as an application, and the far-field electromagnetic response of a faceted reflector surface is compared with that from a spherical reflector surface.

  1. Ray Tracing Modelling of Reflector for Vertical Bifacial Panel

    DEFF Research Database (Denmark)

    Jakobsen, Michael Linde; Thorsteinsson, Sune; Poulsen, Peter Behrensdorff

    2016-01-01

    Bifacial solar panels have recently become a new attractive building block for PV systems. In this work we propose a reflector system for a vertical bifacial panel, and use ray tracing modelling to model the performance. Particularly, we investigate the impact of the reflector volume being filled...... with a refractive medium, and shows the refractive medium improves the reflector performance since it directs almost all the light incident on the incoming plane into the PV panel....

  2. Inflatable Reflector For Solar Power And Radio Communication

    Science.gov (United States)

    Sercel, Joel; Gilchriest, Carl; Ewell, Rich; Herman, Martin; Rascoe, Daniel L.; Nesmith, Bill J.

    1995-01-01

    Report proposes installation of lightweight inflatable reflector structure aboard spacecraft required to both derive power from sunlight and communicate with Earth by radio when apparent position of Earth is at manageably small angle from line of sight to Sun. Structure contains large-aperture paraboloidal reflector aimed toward Sun and concentrates sunlight onto photovoltaic power converter and acts as main reflector of spacecraft radio-communication system.

  3. Properties of wideband resonant reflectors under fully conical light incidence

    OpenAIRE

    Ko, Yeong Hwan; Niraula, Manoj; Lee, Kyu Jin; Magnusson, Robert

    2016-01-01

    Applying numerical modeling coupled with experiments, we investigate the properties of wideband resonant reflectors under fully conical light incidence. We show that the wave vectors pertinent to resonant first-order diffraction under fully conical mounting vary less with incident angle than those associated with reflectors in classical mounting. Therefore, as the evanescent diffracted waves drive the leaky modes responsible for the resonance effects, fully-conical mounting imbues reflectors ...

  4. In-vivo laser induced urethral stricture animal model for investigating the potential of LDR-brachytherapy

    Science.gov (United States)

    Sroka, Ronald; Lellig, Katja; Bader, Markus; Stief, Christian; Weidlich, Patrick; Wechsel, G.; Assmann, Walter; Becker, R.; Fedorova, O.; Khoder, Wael

    2015-02-01

    Purpose: Treatment of urethral strictures is a major challenge in urology. For investigation of different treatment methods an animal model was developed by reproducible induction of urethral strictures in rabbits to mimic the human clinical situation. By means of this model the potential of endoluminal LDR brachytherapy using β-irradiation as prophylaxis of recurrent urethral strictures investigated. Material and Methods: A circumferential urethral stricture was induced by energy deposition using laser light application (wavelength λ=1470 nm, 10 W, 10 s, applied energy 100 J) in the posterior urethra of anaesthetized New Zealand White male rabbits. The radial light emitting fiber was introduced by means of a children resectoscope (14F). The grade of urethral stricture was evaluated in 18 rabbits using videourethroscopy and urethrography at day 28 after stricture induction. An innovative catheter was developed based on a β-irradiation emitting foil containing 32P, which was wrapped around the application system. Two main groups (each n=18) were separated. The "internal urethrotomy group" received after 28days of stricture induction immediately after surgical urethrotomy of the stricture the radioactive catheter for one week in a randomized, controlled and blinded manner. There were 3 subgroups with 6 animals each receiving 0 Gy, 15 Gy and 30 Gy. In contrast animals from the "De Nuovo group" received directly after the stricture induction (day 0) the radioactive catheter also for the duration of one week divided into the same dose subgroups. In order to determine the radiation tolerance of the urethral mucosa, additional animals without any stricture induction received a radioactive catheter applying a total dose of 30 Gy (n=2) and 15 Gy (n=1). Cystourethrography and endoscopic examination of urethra were performed on all operation days for monitoring treatment progress. Based on these investigation a classification of the stricture size was performed and

  5. Lightweight Thermally Stable Multi-Meter Aperture Submillimeter Reflectors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Future astrophysics missions will require lightweight, thermally stable, submillimeter reflectors in sizes of 4m and greater. To date, graphite fiber reinforced...

  6. Jacobi-Bessel analysis of reflector antennas with elliptical apertures

    Science.gov (United States)

    Rahmat-Samii, Yahya

    1987-01-01

    Although many reflector antennas possess circular projected apertures, there are recent satellite and ground antenna applications for which it is desirable to employ reflectors with elliptical apertures. Here a modification of the Jacobi-Bessel expansion is presented for the diffraction analysis of reflectors with elliptical apertures. A comparative study is also performed between this modified Jacobi-Bessel algorithm and the one which uses the Jacobi-Bessel expansion over a circumscribing circular region. Numerical results are presented for offset reflectors with elliptical and circular apertures and the improved convergence properties of the modified algorithm are highlighted.

  7. Solgel grating waveguides for distributed Bragg reflector lasers.

    Science.gov (United States)

    Fardad, M A; Luo, H; Beregovski, Y; Fallahi, M

    1999-04-01

    Solgel grating waveguides and their application to the fabrication of external-cavity distributed Bragg reflector (DBR) lasers are demonstrated. A new composition of aluminosilicate material is developed for the fabrication of single-mode waveguides and Bragg reflectors. An average loss of <0.2 dB/cm is measured in the single-mode waveguides at 1550 nm. The reflectors show filtering greater than 97% near 1530 nm, with a bandwidth of ~0.6 nm . The Bragg reflectors are used as feedback resonators for DBR lasers. Single-mode lasing with a sidemode suppression of better than 25 dB is demonstrated.

  8. SU-F-19A-11: Retrospective Evaluation of Thermal Coverage by Thermobrachytherapy Seed Arrangements of Clinical LDR Prostate Implants

    Energy Technology Data Exchange (ETDEWEB)

    Warrell, G; Shvydka, D; Chen, C; Parsai, E [University of Toledo Medical Center, Toledo, OH (United States)

    2014-06-15

    Purpose: The superiority of a properly-administered combination of radiation therapy and hyperthermia over radiation alone in treatment of human cancers has been demonstrated in multiple studies examining radiobiology, local control, and survival. Unfortunately, hyperthermia is not yet a common modality in oncology practice, due in part to the technical difficulty of heating a deep-seated target volume to sufficient temperature. To address this problem, our group has invented a thermobrachytherapy (TB) seed based on a commonly-used low dose-rate permanent brachytherapy seed for implant in solid tumors. Instead of the tungsten radiographic marker of the standard seed, the TB seed contains one of a self-regulating ferromagnetic alloy. Placement of a patient implanted with such seeds in an oscillating magnetic field generates heat via induction of eddy currents. We present the results of studies of the capability of clinically-realistic TB seed arrangements to adequately heat defined target volumes. Methods: Seed distributions for several past LDR prostate permanent implant brachytherapy patients were reproduced in the finite element analysis software package COMSOL Multiphysics 4.4, with the difference that TB seeds were modelled, rather than the radiation-only seeds actually used for their treatments. The implant geometries were mainly of the modified peripheral loading type; a range of prostatic volumes and blood perfusion rates likely to be seen in a clinical setting were examined. Results: According to the simulations, when distributed to optimize radiation dose, TB seeds also produce sufficient heat to provide thermal coverage of the target given proper selection of the magnetic field strength. However, the thermal distributions may be improved by additional use of hyperthermia-only seeds. Conclusion: A dual-modality seed intended as an alternative to and using the same implantation apparatus and technique as the standard LDR permanent implant seed has been

  9. Bright color reflective displays with interlayer reflectors

    Science.gov (United States)

    Kitson, Stephen; Geisow, Adrian; Rudin, John; Taphouse, Tim

    2011-08-01

    A good solution to the reflective display of color has been a major challenge for the display industry, with very limited color gamuts demonstrated to date. Conventional side-by-side red, green and blue color filters waste two-thirds of incident light. The alternative of stacking cyan, magenta and yellow layers is also challenging -- a 10% loss per layer compounds to nearly 50% overall. Here we demonstrate an architecture that interleaves absorbing-to-clear shutters with matched wavelength selective reflectors. This increases color gamut by reducing losses and more cleanly separating the color channels, and gives much wider choice of electro-optic colorants.

  10. Manufacturing of neutron reflector frame for JMTR

    OpenAIRE

    2010-01-01

    Beryllium has been used as the neutron reflector in the Japan Materials Testing Reactor (JMTR). A beryllium frame is arranged in the JMTR core and the frame consists of 3 sections (North, East and West). Each section has 7 stories of the beryllium blocks. Each block is connected by the aluminum joints. The capsule or the beryllium plug is located in the inside of the beryllium frame. The first criticality achieved in 1968 and the frame has been replaced 6 times and now the 7th frame is being ...

  11. Features of the Calculation Deployment Large Transformable Structures of Different Configurations

    Directory of Open Access Journals (Sweden)

    V. N. Zimin

    2014-01-01

    Full Text Available Despite the significant progress achieved in the design of space transformable structures to ensure a smooth and reliable deployment remains an important task. This type of construction can consist of dozens, hundreds or even thousands of interconnected elements. Deployment transformable space structures in orbit to test their performance in orbital conditions are associated with high material costs. Full deploy: experimental development process transformable structures involve a number of fundamental difficulties: It is impossible to eliminate the influence of gravity and resistance forces conditions. Thus, to calculate deploy of large transformable structures of various configurations is an important stage of their creation. Simulation provides an opportunity to analyze various schemes of deploy, to reveal their advantages and possible disadvantages. For numerical analysis of deploy of such structures is necessary to use modern software modeling of the dynamics of multi-component of mechanical systems such as EULER and Adams. Simulation of deployment space transformable structures was performed taking as example folding flat antenna contours diameter of 5 m and 20 m, foldable spatial calibration reflector diameter of 3 m, deployable antenna reflector truss-type aperture 3×6 m.The results of the calculations represent following characteristics: the time of adoption of the working position structures; form intermediate positions structures during deployment; dependence of opening angles and angular velocities of the design links on the time. The parameters of these calculations can be used as input in the development of structural elements providing deployment. They can also be used to prepare stands for experimental testing of disclosure designs in ground conditions. It should be noted that the theoretical models are the only way to analyze the deployment of such structures for possible emergency situations.

  12. Modeling EERE deployment programs

    Energy Technology Data Exchange (ETDEWEB)

    Cort, K. A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hostick, D. J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Belzer, D. B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Livingston, O. V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2007-11-01

    The purpose of the project was to identify and characterize the modeling of deployment programs within the EERE Technology Development (TD) programs, address possible improvements to the modeling process, and note gaps in knowledge for future research.

  13. Stratospheric Deployment Parafoil Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Stratospheric Deployment Parafoil is a proposed technology that will be designed and tested to provide a greatly superior parachute precision delivery system...

  14. A new concept for solid surface deployable antennas

    Science.gov (United States)

    Guest, S. D.; Pellegrino, S.

    1996-01-01

    This paper presents a new class of rigid-panel deployable antennas. The antenna surface is divided into a series of panels, which fold by wrapping around a central hub. All connections between the panels are made by revolute joints. This new folding technique has significant advantages over previous concepts, both in terms of packaged size, and mechanical simplicity. Furthermore, the size and shape of the packaged reflector can be readily adapted to any particular set of mission requirements. A small hardware demonstrator, which has been designed, manufactured and successfully tested, is discussed in the paper.

  15. Deployable Soft Composite Structures

    OpenAIRE

    Wei Wang; Hugo Rodrigue; Sung-Hoon Ahn

    2016-01-01

    Deployable structure composed of smart materials based actuators can reconcile its inherently conflicting requirements of low mass, good shape adaptability, and high load-bearing capability. This work describes the fabrication of deployable structures using smart soft composite actuators combining a soft matrix with variable stiffness properties and hinge-like movement through a rigid skeleton. The hinge actuator has the advantage of being simple to fabricate, inexpensive, lightweight and sim...

  16. Hybrid grating reflectors: Origin of ultrabroad stopband

    Energy Technology Data Exchange (ETDEWEB)

    Park, Gyeong Cheol; Taghizadeh, Alireza; Chung, Il-Sug, E-mail: ilch@fotonik.dtu.dk [DTU Fotonik, Department of Photonics Engineering, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark)

    2016-04-04

    Hybrid grating (HG) reflectors with a high-refractive-index cap layer added onto a high contrast grating (HCG) provide a high reflectance close to 100% over a broader wavelength range than HCGs. The combination of a cap layer and a grating layer brings a strong Fabry-Perot (FP) resonance as well as a weak guided mode (GM) resonance. Most of the reflected power results from the FP resonance, while the GM resonance plays a key role in achieving a reflectance close to 100% as well as broadening the stopband. An HG sample with 7 InGaAlAs quantum wells included in the cap layer has been fabricated by directly wafer-bonding a III-V cap layer onto a Si grating layer. Its reflection property has been characterized. This heterogeneously integrated HG reflector may allow for a hybrid III-V on Si laser to be thermally efficient, which has promising prospects for silicon photonics light sources and high-speed operation.

  17. Optical Reflectance Measurements for Commonly Used Reflectors

    Science.gov (United States)

    Janecek, Martin; Moses, William W.

    2008-08-01

    When simulating light collection in scintillators, modeling the angular distribution of optical light reflectance from surfaces is very important. Since light reflectance is poorly understood, either purely specular or purely diffuse reflectance is generally assumed. In this paper we measure the optical reflectance distribution for eleven commonly used reflectors. A 440 nm, output power stabilized, un-polarized laser is shone onto a reflector at a fixed angle of incidence. The reflected light's angular distribution is measured by an array of silicon photodiodes. The photodiodes are movable to cover 2pi of solid angle. The light-induced current is, through a multiplexer, read out with a digital multimeter. A LabVIEW program controls the motion of the laser and the photodiode array, the multiplexer, and the data collection. The laser can be positioned at any angle with a position accuracy of 10 arc minutes. Each photodiode subtends 6.3deg, and the photodiode array can be positioned at any angle with up to 10 arc minute angular resolution. The dynamic range for the current measurements is 10 5:1. The measured light reflectance distribution was measured to be specular for several ESR films as well as for aluminum foil, mostly diffuse for polytetrafluoroethylene (PTFE) tape and titanium dioxide paint, and neither specular nor diffuse for Lumirrorreg, Melinexreg and Tyvekreg. Instead, a more complicated light distribution was measured for these three materials.

  18. Dielectric rod feed for compact range reflector

    CERN Document Server

    Balabukha, Nikolay P; Shapkina, Natalia E

    2014-01-01

    A dielectric rod feed with a special radiation pattern of a tabletop form used for the compact range reflector is developed and analyzed. Application of this feed increases the size of the compact range quiet zone generated by the reflector. The feed consists of the dielectric rod made of polystyren, the rod is inserted into the circular waveguide with a corrugated flange. The waveguide is excited by the H11-mode. The rod is covered by the textolite biconical bushing and has a fluoroplastic insert in the vicinity of the bushing. Mathematical modeling was used to obtain the parameters of the feed for the optimal tabletop form of the radiation pattern. The problem of the electromagnetic radiation was solved for metal-dielectric bodies of rotation by method of integral equations with further solving of the problem of the synthesis for feed parameters. The dielectric rod feed was fabricated for the X-frequency range. Feed amplitude and phase patterns were measured in the frequency range 8.2-12.5 GHz. Presented re...

  19. Generalized Toda Mechanics Associated with Loop Algebras (L)(Cr) and (L)(Dr) and Their Reductions

    Institute of Scientific and Technical Information of China (English)

    YANG Zhan-Ying; ZHAO Liu; YLIU Wang-Yun; SHI Kang-Jie

    2005-01-01

    We construct a class of integrable generalization of Toda mechanics with long-range interactions. These systems are associated with the loop algebras L(Cr) and L(Dr) in the sense that their Lax matrices can be realized in terms of the c = 0 representations of the affine Lie algebras Cr(1) and Dr(1) and the interactions pattern involved bears the typical characters of the corresponding root systems. We present the equations of motion and the Hamiltonian structure.These generalized systems can be identified unambiguously by specifying the underlying loop algebra together with an ordered pair of integers (n, m). It turns out that different systems associated with the same underlying loop algebra but with different pairs of integers (n1, m1 ) and (n2, m2) with n2 < n1 and m2 < m1 can be related by a nested Hamiltonian reduction procedure. For all nontrivial generalizations, the extra coordinates besides the standard Toda variables are Poisson non-commute, and when either n or m ≥ 3, the Poisson structure for the extra coordinate variables becomes some Lie algebra (i.e. the extra variables appear linearly on the right-hand side of the Poisson brackets). In the quantum case, such generalizations will become systems with noncommutative variables without spoiling the integrability.

  20. Seaward dipping reflectors along the SW continental margin of India: Evidence for volcanic passive margin

    Digital Repository Service at National Institute of Oceanography (India)

    Ajay, K.K.; Chaubey, A.K.; Krishna, K.S.; Rao, D.G.; Sar, D.

    of the Chagos-Laccadive Ridge system. Velocity structure, seismic character, 2D gravity model and geographic locations of the dipping reflectors suggest that these reflectors are volcanic in origin, which are interpreted as Seaward Dipping Reflectors (SDRs...

  1. Monitoring glaciers and indications of subglacial volcanic activity using small-scale Top-Hat reflectors - An IsViews experiment on Myrdalsjökull, Iceland

    Science.gov (United States)

    Minet, Christian; Duque Biarge, Sergi; Jaenicke, Julia; Münzer, Ulrich; Mayer, Christoph; Franke, Jonas; Guðmundsson, Águst; Parizzi, Alessandro; Fritz, Thomas; Eineder, Michael

    2014-05-01

    Subglacial volcanic eruptions often provide indications of activity some time before the actual catastrophic event. Surface undulations appear on top of the ice cap and meltwater torrents can occur at the glacier margin. Even large scale uplifts of ice caps have been observed. Within the project IsViews a processing chain, based on high spatially and temporally resolved remote sensing imagery, will be developed in order to automatically identify such early indications. The main data used for this analysis are acquired by the TerraSAR-X, TanDEM-X and RapidEye satellites. First investigations concerning the feasibility of the near real-time warning system and the general baseline conditions are carried out on two large plateau glaciers in southern Iceland, namely Mördalsjökull and Vatnajökull. Within the 2013 IsViews field work an experiment was started in order to test a new way of glacier monitoring. Two test sites were established on the Mördalsjökull ice cap (one at the equilibrium line and one below), each consisting of a permanent GPS station and two nearby RADAR reflectors. These RADAR reflectors are specially designed Top-Hat reflectors, which are cheap to manufacture, small (50 cm diameter) and lightweight and therefore easy to handle, transport and deploy. Their special design makes them visible in SAR images independent of orientation, so different acquisition geometries and even different sensors can be used. The drawback of the small, low reflecting Top-Hat can be overcome by using the newly implemented Staring Spotlight Mode of the German SAR Satellite TerraSAR-X, providing an unprecedented resolution of down to 20 cm in the azimuth direction. The reflectors, as point targets, allow absolute positioning within the cm-level in the TerraSAR-X data. Time series of SAR data can be used to derive position and altitude changes of the reflector itself and possibly even melting rates by exploiting the different signal paths. The visibility of the Top

  2. Study variants of hard CFRP reflector for intersatellite communication

    Science.gov (United States)

    Prosuntsov, PV; Reznik, SV; Mikhailovsky, KV; Novikov, AD; Aung, Zaw Ye

    2016-10-01

    The paper deals with the justification of space antennas reflector layout for advanced telecommunication satellites. The selection of design decisions is based on numerical simulations of heat transfer and mechanics processes characteristic of the geostationary orbit conditions. The advantages of parabolic shell of small thickness reflector scheme reinforced with star-shaped ribs on the convex side are demonstrated.

  3. Ray Tracing Modelling of Reflector for Vertical Bifacial Panel

    DEFF Research Database (Denmark)

    Jakobsen, Michael Linde; Thorsteinsson, Sune; Poulsen, Peter Behrensdorff

    2016-01-01

    Bifacial solar panels have recently become a new attractive building block for PV systems. In this work we propose a reflector system for a vertical bifacial panel, and use ray tracing modelling to model the performance. Particularly, we investigate the impact of the reflector volume being filled...

  4. Ellipsoidal reflector for measuring oto-acoustic emissions

    DEFF Research Database (Denmark)

    Epp, Bastian; Pulkki, Ville; Heiskanen, Vesa

    2014-01-01

    A truncated prolate ellipsoidal reflector having the ear canal of a listener at one focal point and large- diaphragm low-noise microphone at the other focal point is proposed for free-field recordings of oto-acoustic emissions. A prototype reflector consisting of three pieces is presented, which ...

  5. Scattering patterns of dihedral corner reflectors with impedance surface impedances

    Science.gov (United States)

    Balanis, Constantine A.; Griesser, Timothy; Liu, Kefeng

    The radar cross section patterns of lossy dihedral corner reflectors are calculated using a uniform geometrical theory of diffraction for impedance surfaces. All terms of up to third order reflections are considered for patterns in the principal plane. The surface waves are included whenever they exist for reactive surface impedances. The dihedral corner reflectors examined have right, obtuse, and acute interior angles, and patterns over the entire 360 deg azimuthal plane are calculated. The surface impedances can be different on the four faces of the dihedral corner reflector; however, the surface impedance must be uniform over each face. Computed cross sections are compared with a moment method technique for a dielectric/ferrite absorber coating on a metallic corner reflector. The analysis of the dihedral corner reflector is important because it demonstrates many of the important scattering contributors of complex targets including both interior and exterior wedge diffraction, half-plane diffraction, and dominant multiple reflections and diffractions.

  6. Properties of wideband resonant reflectors under fully conical light incidence

    CERN Document Server

    Ko, Yeong Hwan; Lee, Kyu Jin; Magnusson, Robert

    2016-01-01

    Applying numerical modeling coupled with experiments, we investigate the properties of wideband resonant reflectors under fully conical light incidence. We show that the wave vectors pertinent to resonant first-order diffraction under fully conical mounting vary less with incident angle than those associated with reflectors in classical mounting. Therefore, as the evanescent diffracted waves drive the leaky modes responsible for the resonance effects, fully-conical mounting imbues reflectors with larger angular tolerance than their classical counterparts. We quantify the angular-spectral performance of representative resonant wideband reflectors in conic and classic mounts by numerical calculations with improved spectra found for fully conic incidence. Moreover, these predictions are verified experimentally for wideband reflectors fashioned in crystalline and amorphous silicon in distinct spectral regions spanning the 1200-1600-nm and 1600-2400-nm spectral bands. These results will be useful in various applic...

  7. Broad spectrum moderators and advanced reflector filters using 208Pb

    DEFF Research Database (Denmark)

    Schönfeldt, Troels; Batkov, K.; Klinkby, Esben Bryndt

    2015-01-01

    thermalizing property of 208Pb to design a broad spectrum moderator, i.e. a moderator which emits thermal and cold neutrons from the same position. Using 208Pb as a reflector filter material is shown to be slightly less efficient than a conventional beryllium reflector filter. However, when surrounding...... the reflector filter by a cold moderator it is possible to regain the neutrons with wavelengths below the Bragg edge, which are suppressed in the beryllium reflector filter. In both the beryllium and lead case surrounding the reflector filter with a cold moderator increases the cold brightness significantly......Cold and thermal neutrons used in neutrons scattering experiments are produced in nuclear reactors and spallation sources. The neutrons are cooled to thermal or cold temperatures in thermal and cold moderators, respectively. The present study shows that it is possible to exploit the poor...

  8. Composite technology in radar equipment. Dopler Meteo radar reflector device

    Directory of Open Access Journals (Sweden)

    A. V. Shumov

    2014-01-01

    Full Text Available The article is devoted features of the application composite materials in radar technology for example adjustment of the development technology of the reflector antenna device DMRL-S - radar for monitoring meteorological conditions.Russian and foreign analogues DMRL-S are made of aluminum, which no longer meets modern requirements for strength and weight. Also aluminum reflectors are not temperature stable. Composite materials are characterized by higher values of specific characteristics: temporary resistance, endurance limit, stiffness, elastic modulus, and less prone to cracking. The use of such materials improves the strength, rigidity and durability.For the manufacture of the DMRL-C reflector used composite materials based on epoxy resins reinforced with fiberglass (both unidirectional and woven. To increase the rigidity and weight reflector is made in the form of three-layer sandwich fiberglass panels with honeycomb core variable height. Design work was carried out in a CAD Siemens NX8.0 / Unigraphics, through which was established mathematical model layered reflector, as well as all accessories used in the manufacture. With the program NX Nastran was held strength calculation and analysis of stiffness on the finite element method.After the manufacture of the product, we measured the standard deviation of the working surface of the reflector from the theoretical surface using a three-dimensional laser scanner. Measurements were made at different angular positions of the reflector, and when loading. It is shown that the maximum strain in the operating modes of operation across the surface of the product does not exceed 4%, which will provide the most accurate operation of the product in any position of the antenna system.As a result of this work reflector design was developed, created and verified by experimental data calculation model. Reflector antenna device of the DMRL-S was manufactured and tested. The reflector was made of reinforced

  9. Impact of HFIR LEU Conversion on Beryllium Reflector Degradation Factors

    Energy Technology Data Exchange (ETDEWEB)

    Ilas, Dan [ORNL

    2013-10-01

    An assessment of the impact of low enriched uranium (LEU) conversion on the factors that may cause the degradation of the beryllium reflector is performed for the High Flux Isotope Reactor (HFIR). The computational methods, models, and tools, comparisons with previous work, along with the results obtained are documented and discussed in this report. The report documents the results for the gas and neutronic poison production, and the heating in the beryllium reflector for both the highly enriched uranium (HEU) and LEU HFIR configurations, and discusses the impact that the conversion to LEU may have on these quantities. A time-averaging procedure was developed to calculate the isotopic (gas and poisons) production in reflector. The sensitivity of this approach to different approximations is gauged and documented. The results show that the gas is produced in the beryllium reflector at a total rate of 0.304 g/cycle for the HEU configuration; this rate increases by ~12% for the LEU case. The total tritium production rate in reflector is 0.098 g/cycle for the HEU core and approximately 11% higher for the LEU core. A significant increase (up to ~25%) in the neutronic poisons production in the reflector during the operation cycles is observed for the LEU core, compared to the HEU case, for regions close to the core s horizontal midplane. The poisoning level of the reflector may increase by more than two orders of magnitude during long periods of downtime. The heating rate in the reflector is estimated to be approximately 20% lower for the LEU core than for the HEU core. The decrease is due to a significantly lower contribution of the heating produced by the gamma radiation for the LEU core. Both the isotopic (gas and neutronic poisons) production and the heating rates are spatially non-uniform throughout the beryllium reflector volume. The maximum values typically occur in the removable reflector and close to the midplane.

  10. Synchronously deployable truss structure

    Science.gov (United States)

    Bush, H. G. (Inventor); Mikulas, M., Jr. (Inventor); Wallsom, E. (Inventor)

    1986-01-01

    A collapsible-expandable truss structure, including first and second spaced surface truss layers having an attached core layer is described. The surface truss layers are composed of a plurality of linear struts arranged in multiple triangular configurations. Each linear strut is hinged at the center and hinge connected at each end to a nodular joint. A passive spring serves as the expansion force to move the folded struts from a stowed collapsed position to a deployed operative final truss configuration. A damper controls the rate of spring expansion for the synchronized deployment of the truss as the folded configuration is released for deployment by the restrain belts. The truss is synchronously extended under the control of motor driven spools.

  11. Mining Deployment Optimization

    Science.gov (United States)

    Čech, Jozef

    2016-09-01

    The deployment problem, researched primarily in the military sector, is emerging in some other industries, mining included. The principal decision is how to deploy some activities in space and time to achieve desired outcome while complying with certain requirements or limits. Requirements and limits are on the side constraints, while minimizing costs or maximizing some benefits are on the side of objectives. A model with application to mining of polymetallic deposit is presented. To obtain quick and immediate decision solutions for a mining engineer with experimental possibilities is the main intention of a computer-based tool. The task is to determine strategic deployment of mining activities on a deposit, meeting planned output from the mine and at the same time complying with limited reserves and haulage capacities. Priorities and benefits can be formulated by the planner.

  12. Deploying OpenStack

    CERN Document Server

    Pepple, Ken

    2011-01-01

    OpenStack was created with the audacious goal of being the ubiquitous software choice for building public and private cloud infrastructures. In just over a year, it's become the most talked-about project in open source. This concise book introduces OpenStack's general design and primary software components in detail, and shows you how to start using it to build cloud infrastructures. If you're a developer, technologist, or system administrator familiar with cloud offerings such as Rackspace Cloud or Amazon Web Services, Deploying OpenStack shows you how to obtain and deploy OpenStack softwar

  13. Modeling EERE Deployment Programs

    Energy Technology Data Exchange (ETDEWEB)

    Cort, Katherine A.; Hostick, Donna J.; Belzer, David B.; Livingston, Olga V.

    2007-11-08

    The purpose of this report is to compile information and conclusions gathered as part of three separate tasks undertaken as part of the overall project, “Modeling EERE Deployment Programs,” sponsored by the Planning, Analysis, and Evaluation office within the Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE). The purpose of the project was to identify and characterize the modeling of deployment programs within the EERE Technology Development (TD) programs, address improvements to modeling in the near term, and note gaps in knowledge where future research is needed.

  14. Remote Systems Design & Deployment

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, Sharon A.; Baker, Carl P.; Valdez, Patrick LJ

    2009-08-28

    The Pacific Northwest National Laboratory (PNNL) was tasked by Washington River Protection Solutions, LLC (WRPS) to provide information and lessons learned relating to the design, development and deployment of remote systems, particularly remote arm/manipulator systems. This report reflects PNNL’s experience with remote systems and lays out the most important activities that need to be completed to successfully design, build, deploy and operate remote systems in radioactive and chemically contaminated environments. It also contains lessons learned from PNNL’s work experiences, and the work of others in the national laboratory complex.

  15. Integrated 222-GHz corner-reflector antennas

    Science.gov (United States)

    Gearhart, Steven S.; Ling, Curtis C.; Rebeiz, Gabriel M.

    1991-01-01

    A high-gain monolithic millimeter-wave antenna has been designed, fabricated, and tested at 222 GHz. The structure consists of a traveling-wave antenna integrated on a 1.2-micron dielectric membrane and suspended in a longitudinal cavity etched in a silicon wafer. A new traveling-wave antenna design yields a wideband input impedance and a low cross-polarization component in the E- and quasi-H-plane patterns. A directivity of 17.7 dB and a main-beam efficiency of 88.5 percent are calculated from the 222-GHz pattern measurements. The integrated corner-reflector antenna is well suited for millimeter- and submillimeter-wave imaging applications in large f-number systems.

  16. Inline microring reflector for photonic applications

    Science.gov (United States)

    Kang, Young Mo

    The microring is a compact resonator that is used as a versatile building block in photonic circuits ranging from filters, modulators, logic gates, sensors, switches, multiplexers, and laser cavities. The Bragg grating is a periodic structure that allows the selection of a narrow bandwidth of spectrum for stable lasing operation. In this dissertation, we study analysis and simulations of a compact microring based reflector assembled by forming a Bragg grating into a loop. With the appropriate design, the microring resonance can precisely align with the reflection peak of the grating while all other peaks are suppressed by reflection nulls of the grating. The field buildup at the resonance effectively amplifies small reflection of the grating, thereby producing significant overall reflection from the ring, and it is possible to achieve a stable narrow linewidth compact laser by forming a single mode laser cavity. The device operation principle is studied from two distinct perspectives; the first looks at coupling of two contra-directional traveling waves within the ring whereas the second aspect investigates relative excitation of the two competing microring resonant modes. In the former method, we relate the steady state amplitudes of the two traveling waves to the reflection spectrum of the grating and solve for the reflection and transmission response for each wavelength of interest. In the latter approach, we expand the field in terms of the resonant modes of the ring cavity and derive transfer functions for reflection and transmission from the nearby mode frequencies. The angular periodicity of the reflective microring geometry allows us to effectively simulate the resonant modes from a computational domain of a single period grating when the continuity boundary condition is applied. We successfully predict the reflection and transmission response of a Si3N 4/SiO2 microring reflector using this method---otherwise too large to carry out full-wave simulation

  17. SU-E-T-431: Feasiblity of Using CT Scout Images for 2D LDR Brachytherpay Planning

    Energy Technology Data Exchange (ETDEWEB)

    Ha, J; Weaver, R [LAC+USC Medical Center, Los Angeles, CA, M. Mariscal (United States)

    2015-06-15

    Purpose: i) To show the feasibility of using CT scout images for 2D low-dose rate brachytherapy planning with BrachyVision (version 10.4); ii) to show their advantages and disadvantages over DRRs. Methods: A phantom was constructed to house a Fletcher-Suite applicator. The phantom is made of Styrofoam with metal BBs positioned at well-defined separations. These markers are used to assess the image distortion in the scout images. Unlike DRRs, scout images are distorted only in the direction normal to the couch direction; therefore, they needed to be scaled unidirectionally prior to importing into BrachyVision. In addition to confirming the scaling is performed correctly by measuring distances between well-positioned BB, we also compare a LDR plan using scout images to a 3D CT-based plan. Results: There is no distortion of the image along the couch direction due to the collimation of the CT scanner. The distortion in the transverse plane can be corrected by multiplying by the ratio of distances between source-to-isocenter and source-to-detector. The results show the distance separations between BBs as measured in scout images and by a caliber are within a few millimeters. Dosimetrically, the difference between the dose rates to points A and B based on scout images and on 3D CT are less than a few percents. The accuracy can be improved by correcting for the distortion on the transverse plane. Conclusion: It is possible to use CT scout images for 2D planning in BrachyVision. This is an advantage because scout images have no metal artifacts often present in CT images or DRRs. Another advantage is the lack of distortion in the couch direction. One major disadvantage is that the image distortion due to beam divergence can be large. This is due to the inherent short distance between source-to-isocenter and source-to-detector on a CT scanner.

  18. Comparison between beta radiation dose distribution due to LDR and HDR ocular brachytherapy applicators using GATE Monte Carlo platform.

    Science.gov (United States)

    Mostafa, Laoues; Rachid, Khelifi; Ahmed, Sidi Moussa

    2016-08-01

    Eye applicators with 90Sr/90Y and 106Ru/106Rh beta-ray sources are generally used in brachytherapy for the treatment of eye diseases as uveal melanoma. Whenever, radiation is used in treatment, dosimetry is essential. However, knowledge of the exact dose distribution is a critical decision-making to the outcome of the treatment. The Monte Carlo technique provides a powerful tool for calculation of the dose and dose distributions which helps to predict and determine the doses from different shapes of various types of eye applicators more accurately. The aim of this work consisted in using the Monte Carlo GATE platform to calculate the 3D dose distribution on a mathematical model of the human eye according to international recommendations. Mathematical models were developed for four ophthalmic applicators, two HDR 90Sr applicators SIA.20 and SIA.6, and two LDR 106Ru applicators, a concave CCB model and a flat CCB model. In present work, considering a heterogeneous eye phantom and the chosen tumor, obtained results with the use of GATE for mean doses distributions in a phantom and according to international recommendations show a discrepancy with respect to those specified by the manufacturers. The QC of dosimetric parameters shows that contrarily to the other applicators, the SIA.20 applicator is consistent with recommendations. The GATE platform show that the SIA.20 applicator present better results, namely the dose delivered to critical structures were lower compared to those obtained for the other applicators, and the SIA.6 applicator, simulated with MCNPX generates higher lens doses than those generated by GATE.

  19. Large, Easily Deployable Structures

    Science.gov (United States)

    Agan, W. E.

    1983-01-01

    Study of concepts for large space structures will interest those designing scaffolding, radio towers, rescue equipment, and prefabricated shelters. Double-fold, double-cell module was selected for further design and for zero gravity testing. Concept is viable for deployment by humans outside space vehicle as well as by remotely operated manipulator.

  20. Deployment & Market Transformation (Brochure)

    Energy Technology Data Exchange (ETDEWEB)

    2012-04-01

    NREL's deployment and market transformation (D and MT) activities encompass the laboratory's full range of technologies, which span the energy efficiency and renewable energy spectrum. NREL staff educates partners on how they can advance sustainable energy applications and also provides clients with best practices for reducing barriers to innovation and market transformation.

  1. Deploying Node.js

    CERN Document Server

    Pasquali, Sandro

    2015-01-01

    If you are an intermediate or advanced developer deploying your Node.js applications, then this book is for you. If you have already built a Node application or module and want to take your knowledge to the next level, this book will help you find your way.

  2. Laser Ranging to the Lost Lunokhod~1 Reflector

    CERN Document Server

    Murphy, T W; Battat, J B R; Hoyle, C D; Johnson, N H; McMillan, R J; Michelsen, E L; Stubbs, C W; Swanson, H E

    2011-01-01

    In 1970, the Soviet Lunokhod 1 rover delivered a French-built laser reflector to the Moon. Although a few range measurements were made within three months of its landing, these measurements---and any that may have followed---are unpublished and unavailable. The Lunokhod 1 reflector was, therefore, effectively lost until March of 2010 when images from the Lunar Reconnaissance Orbiter (LRO) provided a positive identification of the rover and determined its coordinates with uncertainties of about 100 m. This allowed the Apache Point Observatory Lunar Laser-ranging Operation (APOLLO) to quickly acquire a laser signal. The reflector appears to be in excellent condition, delivering a signal roughly four times stronger than its twin reflector on the Lunokhod 2 rover. The Lunokhod 1 reflector is especially valuable for science because it is closer to the Moon's limb than any of the other reflectors and, unlike the Lunokhod 2 reflector, we find that it is usable during the lunar day. We report the selenographic positi...

  3. Minimal percentage of dose received by 90% of the urethra (%UD90 is the most significant predictor of PSA bounce in patients who underwent low-dose-rate brachytherapy (LDR-brachytherapy for prostate cancer

    Directory of Open Access Journals (Sweden)

    Tanaka Nobumichi

    2012-09-01

    Full Text Available Abstract Background To clarify the significant clinicopathological and postdosimetric parameters to predict PSA bounce in patients who underwent low-dose-rate brachytherapy (LDR-brachytherapy for prostate cancer. Methods We studied 200 consecutive patients who received LDR-brachytherapy between July 2004 and November 2008. Of them, 137 patients did not receive neoadjuvant or adjuvant androgen deprivation therapy. One hundred and forty-two patients were treated with LDR-brachytherapy alone, and 58 were treated with LDR-brachytherapy in combination with external beam radiation therapy. The cut-off value of PSA bounce was 0.1 ng/mL. The incidence, time, height, and duration of PSA bounce were investigated. Clinicopathological and postdosimetric parameters were evaluated to elucidate independent factors to predict PSA bounce in hormone-naïve patients who underwent LDR-brachytherapy alone. Results Fifty patients (25% showed PSA bounce and 10 patients (5% showed PSA failure. The median time, height, and duration of PSA bounce were 17 months, 0.29 ng/mL, and 7.0 months, respectively. In 103 hormone-naïve patients treated with LDR-brachytherapy alone, and univariate Cox proportional regression hazard model indicated that age and minimal percentage of the dose received by 30% and 90% of the urethra were independent predictors of PSA bounce. With a multivariate Cox proportional regression hazard model, minimal percentage of the dose received by 90% of the urethra was the most significant parameter of PSA bounce. Conclusions Minimal percentage of the dose received by 90% of the urethra was the most significant predictor of PSA bounce in hormone-naïve patients treated with LDR-brachytherapy alone.

  4. Performance of a PV module augmented by a plane reflector

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, G. E; Hussein, H. M. S; Mohamad, M. A [Dokki, Giza (Egypt)

    2000-07-01

    This paper presents a comparative experimental study on the performance of a PV module augmented by a south facing titled plane reflector and another identical one without reflector. The tilt angles of the two PV modules and reflector overhang are selected to be according to a previous theoretical study by the authors. The reflector tilt angle has been changed once a month so that the reflected beams from the plane reflector cover the total surface area of the PV module all days of every month during the high solar radiation period (i.e. three hours before and after solar noon). The study has been carried out on the two PV modules for a complete year under the actual atmospheric conditions of Cairo, Egypt. The measuring system used in the study comprises a data acquisition system, a computer, an electronic load and weather station. The experimental results indicate that the plane reflector enhances the yearly output energy of the PV module y about 22%. [Spanish] Este articulo presenta un estudio comparativo experimental sobre el rendimiento de un modulo de PV aumentado por un reflector plano inclinado mirando hacia el sur y otro identico sin reflector. Los angulos de inclinacion de los dos modulos y el reflector sobresaliente se seleccionan para que esten de acuerdo con un estudio teorico previo hecho por los autores. El angulo de inclinacion del reflector se cambio una vez al mes de manera que los rayos reflejados por el reflector plano cubrieran el area total de la superficie del modulo de PV todos los dias de cada mes durante el periodo de radiacion alto (o sea tres horas antes y despues del medio dia solar). El estudio ha sido llevado a cabo en dos modulos de PV durante un ano completo bajo condiciones atmosfericas reales de El Cairo, Egipto. El sistema de medicion usado en el estudio comprende un sistema de adquisicion de datos, una computadora, una memoria electronica y una estacion climatologica. Los resultados experimentales indican que el reflector plano

  5. Incidental Reflector Comparison of Containerized Dry Fire Extinguishing Agents

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, Bryan Scott [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wysong, Andrew Russell [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-12-14

    This document addresses the incidental reflector reactivity worth of containerized fire extinguishing agents authorized for use in PF-4 at Los Alamos National Laboratory (LANL). The intent of the document is to analyze dry fire extinguishing agent that remains in a container and is not actively being used in a fire emergency. The incidental reflector reactivity worth is determined by comparison to various thicknesses of close fitting water reflection which is commonly used to bound incidental reflectors in criticality safety evaluations. The conclusion is that even in unlimited quantities, when containerized the authorized dry fire extinguishing agents are bound by 0.4 inches of close fitting water.

  6. Identifying Reflectors in Seismic Images via Statistic and Syntactic Methods

    Directory of Open Access Journals (Sweden)

    Carlos A. Perez

    2010-04-01

    Full Text Available In geologic interpretation of seismic reflection data, accurate identification of reflectors is the foremost step to ensure proper subsurface structural definition. Reflector information, along with other data sets, is a key factor to predict the presence of hydrocarbons. In this work, mathematic and pattern recognition theory was adapted to design two statistical and two syntactic algorithms which constitute a tool in semiautomatic reflector identification. The interpretive power of these four schemes was evaluated in terms of prediction accuracy and computational speed. Among these, the semblance method was confirmed to render the greatest accuracy and speed. Syntactic methods offer an interesting alternative due to their inherently structural search method.

  7. Corner-cube retro-reflector instrument for advanced lunar laser ranging

    Science.gov (United States)

    Turyshev, Slava G.; Williams, James G.; Folkner, William M.; Gutt, Gary M.; Baran, Richard T.; Hein, Randall C.; Somawardhana, Ruwan P.; Lipa, John A.; Wang, Suwen

    2013-08-01

    Lunar laser ranging (LLR) has made major contributions to our understanding of the Moon's internal structure and the dynamics of the Earth-Moon system. Because of the recent improvements of the ground-based laser ranging facilities, the present LLR measurement accuracy is limited by the retro-reflectors currently on the lunar surface, which are arrays of small corner-cubes. Because of lunar librations, the surfaces of these arrays do not, in general, point directly at the Earth. This effect results in a spread of arrival times, because each cube that comprises the retroreflector is at a slightly different distance from the Earth, leading to the reduced ranging accuracy. Thus, a single, wide aperture corner-cube could have a clear advantage. In addition, after nearly four decades of successful operations the retro-reflectors arrays currently on the Moon started to show performance degradation; as a result, they yield still useful, but much weaker return signals. Thus, fresh and bright instruments on the lunar surface are needed to continue precision LLR measurements. We have developed a new retro-reflector design to enable advanced LLR operations. It is based on a single, hollow corner cube with a large aperture for which preliminary thermal, mechanical, and optical design and analysis have been performed. The new instrument will be able to reach an Earth-Moon range precision of 1-mm in a single pulse while being subjected to significant thermal variations present on the lunar surface, and will have low mass to allow robotic deployment. Here we report on our design results and instrument development effort.

  8. Control of antenna-feed attitude and reflector vibrations in large spaceborne antennas by mechanical decoupling and movable dampers

    Science.gov (United States)

    Wang, P. K. C.; Hong, E. C.; Sarina, J. S.

    1983-07-01

    Simple, practical methods for damping reflector vibrations and designing antenna-feed attitude control systems in large deployable spaceborne antennas are proposed. The former involves a movable damper which is positioned so that the rate-of-change of total vibrational energy is minimized. The latter introduces a mechanical decoupler between the flexible boom and the antenna-feed, whereby the feed-attitude control system can be designed independent of boom dynamics. The validity of these approaches are substantiated by analytical studies, computer simulation, and experimental studies.

  9. Space Reflector Materials for Prometheus Application

    Energy Technology Data Exchange (ETDEWEB)

    J. Nash; V. Munne; LL Stimely

    2006-01-31

    The two materials studied in depth which appear to have the most promise in a Prometheus reflector application are beryllium (Be) and beryllium oxide (BeO). Three additional materials, magnesium oxide (MgO), alumina (Al{sub 2}O{sub 3}), and magnesium aluminate spinel (MgAl{sub 2}O{sub 4}) were also recently identified to be of potential interest, and may have promise in a Prometheus application as well, but are expected to be somewhat higher mass than either a Be or BeO based reflector. Literature review and analysis indicates that material properties for Be are largely known, but there are gaps in the properties of Be0 relative to the operating conditions for a Prometheus application. A detailed preconceptual design information document was issued providing material properties for both materials (Reference (a)). Beryllium oxide specimens were planned to be irradiated in the JOY0 Japanese test reactor to partially fill the material property gaps, but more testing in the High Flux Isotope Reactor (HFIR) test reactor at Oak Ridge National Laboratory (ORNL) was expected to be needed. A key issue identified for BeO was obtaining material for irradiation testing with an average grain size of {approx}5 micrometers, reminiscent of material for which prior irradiation test results were promising. Current commercially available material has an average grain size of {approx}10 micrometers. The literature indicated that improved irradiation performance could be expected (e.g., reduced irradiation-induced swelling) with the finer grain size material. Confirmation of these results would allow the use of historic irradiated materials test results from the literature, reducing the extent of required testing and therefore the cost of using this material. Environmental, safety and health (ES&H) concerns associated with manufacturing are significant but manageable for Be and BeO. Although particulate-generating operations (e.g., machining, grinding, etc.) involving Be

  10. Dedicated Deployable Aerobraking Structure

    Science.gov (United States)

    Giersch, Louis R.; Knarr, Kevin

    2010-01-01

    A dedicated deployable aerobraking structure concept was developed that significantly increases the effective area of a spacecraft during aerobraking by up to a factor of 5 or more (depending on spacecraft size) without substantially increasing total spacecraft mass. Increasing the effective aerobraking area of a spacecraft (without significantly increasing spacecraft mass) results in a corresponding reduction in the time required for aerobraking. For example, if the effective area of a spacecraft is doubled, the time required for aerobraking is roughly reduced to half the previous value. The dedicated deployable aerobraking structure thus enables significantly shorter aerobraking phases, which results in reduced mission cost, risk, and allows science operations to begin earlier in the mission.

  11. Design optimization studies for large-scale contoured beam deployable satellite antennas

    Science.gov (United States)

    Tanaka, Hiroaki

    2006-05-01

    Satellite communications systems over the past two decades have become more sophisticated and evolved new applications that require much higher flux densities. These new requirements to provide high data rate services to very small user terminals have in turn led to the need for large aperture space antenna systems with higher gain. Conventional parabolic reflectors constructed of metal have become, over time, too massive to support these new missions in a cost effective manner and also have posed problems of fitting within the constrained volume of launch vehicles. Designers of new space antenna systems have thus begun to explore new design options. These design options for advanced space communications networks include such alternatives as inflatable antennas using polyimide materials, antennas constructed of piezo-electric materials, phased array antenna systems (especially in the EHF bands) and deployable antenna systems constructed of wire mesh or cabling systems. This article updates studies being conducted in Japan of such deployable space antenna systems [H. Tanaka, M.C. Natori, Shape control of space antennas consisting of cable networks, Acta Astronautica 55 (2004) 519-527]. In particular, this study shows how the design of such large-scale deployable antenna systems can be optimized based on various factors including the frequency bands to be employed with such innovative reflector design. In particular, this study investigates how contoured beam space antennas can be effective by constructed out of so-called cable networks or mesh-like reflectors. This design can be accomplished via "plane wave synthesis" and by the "force density method" and then to iterate the design to achieve the optimum solution. We have concluded that the best design is achieved by plane wave synthesis. Further, we demonstrate that the nodes on the reflector are best determined by a pseudo-inverse calculation of the matrix that can be interpolated so as to achieve the minimum

  12. Validation of a unique concept for a low-cost, lightweight space-deployable antenna structure

    Science.gov (United States)

    Freeland, R. E.; Bilyeu, G. D.; Veal, G. R.

    1993-01-01

    An experiment conducted in the framework of a NASA In-Space Technology Experiments Program based on a concept of inflatable deployable structures is described. The concept utilizes very low inflation pressure to maintain the required geometry on orbit and gravity-induced deflection of the structure precludes any meaningful ground-based demonstrations of functions performance. The experiment is aimed at validating and characterizing the mechanical functional performance of a 14-m-diameter inflatable deployable reflector antenna structure in the orbital operational environment. Results of the experiment are expected to significantly reduce the user risk associated with using large space-deployable antennas by demonstrating the functional performance of a concept that meets the criteria for low-cost, lightweight, and highly reliable space-deployable structures.

  13. The Novel Y-Branch With Two Reflectors

    Institute of Scientific and Technical Information of China (English)

    Ruei-Chang Lu; Yu-Pin Liao

    2003-01-01

    A novel Y-branch waveguide with two reflectors is proposed. The normalized transmitted power for the branching angle of 50°is greater than 70%, which is higher than conventional Y-branch with such wide angle.

  14. Lightweight Thermally Stable Multi-Meter Aperture Submillimeter Reflectors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of the Phase II effort will be an affordable demonstrated full-scale design for a thermally stable multi-meter submillimeter reflector. The Phase I...

  15. Proton radiation effects on optical constants of Al film reflector

    Institute of Scientific and Technical Information of China (English)

    Liu Hai; Wei Qiang; He Shi-Yu; Zhao Dan

    2006-01-01

    The Al film reflectors can yield a high-reflectance over a broad wavelength region, and have been widely used in the spacecraft optical instruments for high quality optical applications. Under the irradiation of charged particles in the Earth radiation belt, the reflectors could be deteriorated. In order to reveal the deterioration mechanism, the change in optical constants of Al film reflector induced by proton radiation with 60 keV was studied in an environment of vacuum with heat sink. Experimental results showed that when the radiation damage primarily occurs in the Al reflecting film,the extinction coefficient k will gradually decrease with increasing radiation fluence, which results in the decrease of the energies of reflective light. Therefore, the proton radiation induced an obvious degradation of spectral reflectance in the wavelength region from 200 to 800 nm on the Al film reflector.

  16. Friction-Sensing Reflector Array Patches (FRAP) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Research Support Instruments, Inc. (RSI) proposes to develop the Friction-Sensing Reflector Array Patches (FRAP), a technology that will measure the shear stress...

  17. Backscattering reduction of corner reflectors using SCS technique

    Science.gov (United States)

    Ajaikumar, V.; Jose, K. A.; Aanandan, C. K.; Mohanan, P.; Nair, K. G.

    1992-10-01

    The paper reports the use of a simulated corrugated surface (SCS) to reduce radar cross section of dihedral corner reflectors. The focus is on 90-deg corner reflectors, since they are involved in many targets and normally show an enhancement in RCS. The backscattering cross section of the dihedral corner reflector, which is large due to the mutual perpendicularity of the two flat surfaces, is found to be greatly reduced for TE polarization. This simple method is determined to be very effective in reducing the RCS of corner reflectors for any corner angle by suitably selecting the parameters of SCS. This may find potential use in strategic RCS reduction of targets in defense and space applications.

  18. RCS analysis and reduction for lossy dihedral corner reflectors

    Science.gov (United States)

    Griesser, Timothy; Balanis, Constantine A.; Liu, Kefeng

    1989-05-01

    The radar-cross-section (RCS) patterns of lossy dihedral corner reflectors are calculated, using a uniform geometrical theory of diffraction for impedance surfaces. All terms of up to third-order reflections and diffractions are considered for patterns in the principal plane. The surface waves are included whenever they exist for reactive surface impedances. The dihedral corner reflectors examined have right, obtuse, and acute interior angles, and patterns over the entire 360 deg azimuthal plane are calculated. The surface impedances can be different on the four faces of the dihedral corner reflector; however, the surface impedance must be uniform over each face. Computed cross sections are compared with the results of a moment-method technique for a dielectric/ferrite absorber coating on a metallic corner reflector.

  19. Semitransparent organic solar cells with organic wavelength dependent reflectors

    NARCIS (Netherlands)

    Galagan, Y.O.; Debije, M.G.; Blom, P.W.M.

    2011-01-01

    Semitransparent organic solar cells employing solution-processable organic wavelength dependent reflectors of chiral nematic (cholesteric) liquid crystals are demonstrated. The cholesteric liquid crystal (CLC) reflects only in a narrow band of the solar spectrum and remains transparent for the

  20. Evaluation of the Benefits of Reflectorized Sign Posts to Drivers

    Directory of Open Access Journals (Sweden)

    Erdinç Öner

    2013-03-01

    Full Text Available In United States Federal Highway Administration (FHWA provides departments of transportation (DOTs the option of using retroreflective material on sign posts when the DOTs determine that there is a need to draw attention to the sign, especially at night. The State of Ohio Department of Transportation (ODOT required all Stop, Yield, Do Not Enter, and Wrong Way sign posts to be reflectorized with RED reflective sheeting material and all Chevron, Stop Ahead, and One/Two Large Directional Arrow sign posts to be reflectorized with YELLOW (sign background color reflective sheeting material as part of ODOT Comprehensive Highway Safety Plan and FHWA' recommendations.In this study, a photometric analysis and a human factors analysis were conducted to estimate the benefits of reflectorized sign posts to driver visual perception, driver guidance and driver comprehension. The study showed that the reflectorized sign posts improve detection, recognition, and comprehension of traffic signs for drivers, especially in nighttime driving conditions.

  1. An evaluation of a Low-Dose-Rate (LDR) brachytherapy procedure using a systems engineering & error analysis methodology for health care (SEABH) - (SAVE)

    LENUS (Irish Health Repository)

    Chadwick, Liam

    2012-03-12

    Health Care Failure Modes and Effects Analysis (HFMEA®) is an established tool for risk assessment in health care. A number of deficiencies have been identified in the method. A new method called Systems and Error Analysis Bundle for Health Care (SEABH) was developed to address these deficiencies. SEABH has been applied to a number of medical processes as part of its validation and testing. One of these, Low Dose Rate (LDR) prostate Brachytherapy is reported in this paper. The case study supported the validity of SEABH with respect to its capacity to address the weaknesses of (HFMEA®).

  2. OPTIMIZACIÓN DE REDES 3G UTILIZANDO ALGORITMOS CONTROL DE ADMISIÓN DE LLAMADA (CAC Y REORGANIZACIÓN DE CARGA (LDR

    Directory of Open Access Journals (Sweden)

    Darío Fernando Romo Cabrera

    2012-08-01

    Full Text Available Este artículo presenta el comportamiento de los algoritmos control de admisión de llamada CAC y reorganización de la carga LDR. Se  analizan dos escenarios donde son utilizados para mejorar el rendimiento de la red 3G. En el primero de ellos se presenta un caso de congestión de potencia en el uplink y en el segundo se analiza el nivel de congestión de elementos de canal CE en el uplink.

  3. Study on Segmented Reflector Lamp Design Based on Error Analysis

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This paper discusses the basic principle and design m ethod for light distribution of car lamp, introduces an important development: h igh efficient and flexible car lamp with reflecting light distribution-segmente d reflector (multi-patch) car lamp, and puts out a design method for segmented reflector based on error analysis. Unlike classical car lamp with refractive lig ht distribution, the method of reflecting light distribution gives car lamp desi gn more flexibility. In the case of guarantying the li...

  4. Reflectors for SAR performance testing-second edition

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter

    2014-02-01

    Synthetic Aperture Radar (SAR) performance testing and estimation is facilitated by observing the system response to known target scene elements. Trihedral corner reflectors and other canonical targets play an important role because their Radar Cross Section (RCS) can be calculated analytically. However, reflector orientation and the proximity of the ground and mounting structures can significantly impact the accuracy and precision with which measurements can be made. These issues are examined in this report.

  5. Measurement of small antenna reflector losses for radiometer calibration budget

    OpenAIRE

    Skou, Niels

    1997-01-01

    Antenna reflector losses play an important role in the calibration budget for a microwave radiometer. If the losses are small, they are difficult to measure by traditional means. However, they can be assessed directly by radiometric means using the sky brightness temperature as incident radiation. This paper describes how such measurements are carried out as well as a suitable experimental setup. The main reflector of the European Space Agency's MIMR system is used to demonstrate the principle

  6. Accurate antenna reflector loss measurements for radiometer calibration budget

    DEFF Research Database (Denmark)

    Skou, Niels

    1996-01-01

    Antenna reflector losses may play an important role in the calibration budget for a microwave radiometer. If the losses are small they are difficult to measure by traditional means. However, they can be assessed directly by radiometric means using the sky brightness temperature as incident radiat...... radiation. The paper describes how such measurements are carried out as well as a suitable experimental set-up. The main reflector of the European Space Agency's MIMR system is used to demonstrate the principle...

  7. Differential correction method applied to measurement of the FAST reflector

    Science.gov (United States)

    Li, Xin-Yi; Zhu, Li-Chun; Hu, Jin-Wen; Li, Zhi-Heng

    2016-08-01

    The Five-hundred-meter Aperture Spherical radio Telescope (FAST) adopts an active deformable main reflector which is composed of 4450 triangular panels. During an observation, the illuminated area of the reflector is deformed into a 300-m diameter paraboloid and directed toward a source. To achieve accurate control of the reflector shape, positions of 2226 nodes distributed around the entire reflector must be measured with sufficient precision within a limited time, which is a challenging task because of the large scale. Measurement of the FAST reflector makes use of stations and node targets. However, in this case the effect of the atmosphere on measurement accuracy is a significant issue. This paper investigates a differential correction method for total stations measurement of the FAST reflector. A multi-benchmark differential correction method, including a scheme for benchmark selection and weight assignment, is proposed. On-site evaluation experiments show there is an improvement of 70%-80% in measurement accuracy compared with the uncorrected measurement, verifying the effectiveness of the proposed method.

  8. Light Readout Optimisation using Wavelength Shifter - Reflector Combinations

    Energy Technology Data Exchange (ETDEWEB)

    Mavrokoridis, Konstantinos, E-mail: k.mavrokoridis@liverpool.ac.uk [Department of Physics, University of Liverpool, Oliver Lodge Lab, Oxford Street, Liverpool, L69 7ZE (United Kingdom)

    2011-07-25

    The use of reflectors coated with a wavelength shifter (WLS) along with standard bialkali PMTs is an economical method for an efficient readout system for vacuum ultra violet (VUV) light produced in large liquid argon detectors. Various thicknesses of tetraphenyl butadiene (TPB) were deposited by spraying and vacuum evaporation onto both specular 3M{sup TM}-foil and diffuse Tetratex{sup TM} (TTX) reflectors. 128 nm VUV light generated in 1 bar argon gas by a 5.4 MeV {alpha} source was detected by a 3-inch bialkali borosilicate PMT within a 1 m tube lined internally with a TPB coated reflector. The light collection was recorded as a function of separation between source and PMT for each combination of coating and reflector for distances up to 1m. Reflection coefficients of TPB coated reflectors were measured using a spectroradiometer. WLS coating on the PMT window was also studied. The optimum coating and reflector combination was TPB evaporated on TTX. Measurements with coating thicknesses of 0.2 mg/cm{sup 2} and 1.0 mg/cm{sup 2} yielded a similar performance. The best PMT window coating is obtained by TPB evaporation of 0.05 mg/cm{sup 2}.

  9. Scattering characteristics computation method for corner reflectors in arbitrary illumination conditions

    OpenAIRE

    Sukharevsky, Oleg I.; Vasilets, Vitaly A.; Nechitaylo, Sergey V.

    2015-01-01

    The calculation method for obtaining scattering characteristics of corner reflectors is proposed. The method allows calculating the radar cross-section of corner reflectors for arbitrary aspect angles. The method proposes separating the smooth part of reflectors and some neighborhood of their edges (including that of inner edges). The method accounts for multiple reflections between smooth parts of the reflector surface. In addition, the reflector surface can have a radar absorbing or dielect...

  10. Theoretical analysis of solar thermal collector and flat plate bottom reflector with a gap between them

    OpenAIRE

    Hiroshi Tanaka

    2015-01-01

    Augmentation of solar radiation absorbed on a flat plate solar thermal collector by a flat plate bottom reflector was numerically determined when there was a gap between the collector and reflector. The inclination of both the collector and reflector was assumed to be adjustable according to the season. A mirror-symmetric plane of the collector to the reflector was introduced, and a graphical model was proposed to calculate the amount of solar radiation reflected by the reflector and then abs...

  11. Self-Deployable Membrane Structures

    Science.gov (United States)

    Sokolowski, Witold M.; Willis, Paul B.; Tan, Seng C.

    2010-01-01

    Currently existing approaches for deployment of large, ultra-lightweight gossamer structures in space rely typically upon electromechanical mechanisms and mechanically expandable or inflatable booms for deployment and to maintain them in a fully deployed, operational configuration. These support structures, with the associated deployment mechanisms, launch restraints, inflation systems, and controls, can comprise more than 90 percent of the total mass budget. In addition, they significantly increase the stowage volume, cost, and complexity. A CHEM (cold hibernated elastic memory) membrane structure without any deployable mechanism and support booms/structure is deployed by using shape memory and elastic recovery. The use of CHEM micro-foams reinforced with carbon nanotubes is considered for thin-membrane structure applications. In this advanced structural concept, the CHEM membrane structure is warmed up to allow packaging and stowing prior to launch, and then cooled to induce hibernation of the internal restoring forces. In space, the membrane remembers its original shape and size when warmed up. After the internal restoring forces deploy the structure, it is then cooled to achieve rigidization. For this type of structure, the solar radiation could be utilized as the heat energy used for deployment and space ambient temperature for rigidization. The overall simplicity of the CHEM self-deployable membrane is one of its greatest assets. In present approaches to space-deployable structures, the stow age and deployment are difficult and challenging, and introduce a significant risk, heavy mass, and high cost. Simple procedures provided by CHEM membrane greatly simplify the overall end-to-end process for designing, fabricating, deploying, and rigidizing large structures. The CHEM membrane avoids the complexities associated with other methods for deploying and rigidizing structures by eliminating deployable booms, deployment mechanisms, and inflation and control systems

  12. Joint for deployable structures

    Science.gov (United States)

    Craighead, N. D., II; Preliasco, R. J.; Hult, T. D. (Inventor)

    1985-01-01

    A joint is described for connecting a pair of beams to pivot them between positions in alignment or beside one another, which is of light weight and which operates in a controlled manner. The joint includes a pair of fittings and at least one center link having opposite ends pivotally connected to opposite fittings and having axes that pass through centerplates of the fittings. A control link having opposite ends pivotally connected to the different fittings controls their relative orientations, and a toggle assemly holds the fittings in the deployed configuration wherein they are aligned. The fittings have stops that lie on one side of the centerplane opposite the toggle assembly.

  13. On the Design of Radar Corner Reflectors for Deformation Monitoring in Multi-Frequency InSAR

    Directory of Open Access Journals (Sweden)

    Matthew C. Garthwaite

    2017-06-01

    Full Text Available Trihedral corner reflectors are being increasingly used as point targets in deformation monitoring studies using interferometric synthetic aperture radar (InSAR techniques. The frequency and size dependence of the corner reflector Radar Cross Section (RCS means that no single design can perform equally in all the possible imaging modes and radar frequencies available on the currently orbiting Synthetic Aperture Radar (SAR satellites. Therefore, either a corner reflector design tailored to a specific data type or a compromise design for multiple data types is required. In this paper, I outline the practical and theoretical considerations that need to be made when designing appropriate radar targets, with a focus on supporting multi-frequency SAR data. These considerations are tested by performing field experiments on targets of different size using SAR images from TerraSAR-X, COSMO-SkyMed and RADARSAT-2. Phase noise behaviour in SAR images can be estimated by measuring the Signal-to-Clutter ratio (SCR in individual SAR images. The measured SCR of a point target is dependent on its RCS performance and the influence of clutter near to the deployed target. The SCR is used as a metric to estimate the expected InSAR displacement error incurred by the design of each target and to validate these observations against theoretical expectations. I find that triangular trihedral corner reflectors as small as 1 m in dimension can achieve a displacement error magnitude of a tenth of a millimetre or less in medium-resolution X-band data. Much larger corner reflectors (2.5 m or greater are required to achieve the same displacement error magnitude in medium-resolution C-band data. Compromise designs should aim to satisfy the requirements of the lowest SAR frequency to be used, providing that these targets will not saturate the sensor of the highest frequency to be used. Finally, accurate boresight alignment of the corner reflector can be critical to the overall

  14. Study of back reflectors for thin film silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, H.; Mai, Y. [Baoding Tianwei Solarfilms Co., Ltd., Baoding 071051 (China); Wan, M. [Department of Chemistry and Material Science, Hunan Institute of Humanities, Science and Technology, Loudi 417000 (China); Gao, J.; Wang, Y.; He, T.; Feng, Y.; Yin, J.; Du, J.; Wang, J.; Sun, R. [Baoding Tianwei Solarfilms Co., Ltd., Baoding 071051 (China); Huang, Y., E-mail: y.huang@btw-solarfilms.com [Baoding Tianwei Solarfilms Co., Ltd., Baoding 071051 (China)

    2013-07-31

    In this study, the reflection properties of transparent conductive oxide (TCO) films i.e. aluminum doped zinc oxide (ZnO:Al) and boron doped zinc oxide (ZnO:B) films plus aluminum (Al) films or white polyvinyl butyral (PVB) foils, which are usually used as the combined back reflectors of thin film silicon solar cells, are investigated. Sputtered ZnO:Al films were etched in diluted hydrochloric acid (1%) to achieve rough surface structures while textured ZnO:B films were directly prepared by a low pressure chemical vapor deposition technique. It is found that the rough TCO/Al reflectors show a low total reflection, which is mainly due to the parasitic absorption by the surface plasmons at the rough TCO/Al interfaces as well as the absorption in the TCO films. Differently, the rough TCO/white PVB foil reflectors display a slightly high light reflection regardless of the influence of the rough interface without the excitation of surface plasmons. Thus, the TCO/white PVB foil back reflectors could be a good candidate with respect to light utilization when they are applied in thin film silicon solar cells. - Highlights: • White polyvinyl butyral and transparent conductive oxide materials are used. • The reflection properties of TCO/Al and TCO/white PVB foil reflectors are studied. • The ZnO:Al and ZnO:B films are used as two types of TCO materials. • TCO/white PVB foil reflector shows a high reflection compared to TCO/Al reflector.

  15. Field Deployable DNA analyzer

    Energy Technology Data Exchange (ETDEWEB)

    Wheeler, E; Christian, A; Marion, J; Sorensen, K; Arroyo, E; Vrankovich, G; Hara, C; Nguyen, C

    2005-02-09

    This report details the feasibility of a field deployable DNA analyzer. Steps for swabbing cells from surfaces and extracting DNA in an automatable way are presented. Since enzymatic amplification reactions are highly sensitive to environmental contamination, sample preparation is a crucial step to make an autonomous deployable instrument. We perform sample clean up and concentration in a flow through packed bed. For small initial samples, whole genome amplification is performed in the packed bed resulting in enough product for subsequent PCR amplification. In addition to DNA, which can be used to identify a subject, protein is also left behind, the analysis of which can be used to determine exposure to certain substances, such as radionuclides. Our preparative step for DNA analysis left behind the protein complement as a waste stream; we determined to learn if the proteins themselves could be analyzed in a fieldable device. We successfully developed a two-step lateral flow assay for protein analysis and demonstrate a proof of principle assay.

  16. VSOP-2 Antenna and its Structure

    Science.gov (United States)

    Higuchi, K.; Kishimoto, N.; Mizuno, T.; Kawahara, K.; Tachikawa, S.; Murata, Y.; Tsuboi, M.; Ogawa, H.; Kimura, S.; Ujihara, H.; Meguro, A.; Tanaka, H.; Yoshihara, M.; Iikura, S.

    2009-08-01

    To achieve scientific improvements from VSOP (HALCA) to VSOP-2 (ASTRO-G), the satellite design incorporates the engineering characteristics of a large-scale deployable antenna of offset Cassegrain type with observation bands of 8, 22, and 43 GHz. The antenna subsystem requires the surface accuracy of 0.4mm RMS on the main reflector named LDR (Large-scale Deployable Reflector) of about 9m in diameter. An off-axis paraboloid reflector is adopted to achieve this surface accuracy for millimeter-wave observation. The main reflector is composed of seven deployable modular antennas, and each of the modules employs a new idea of radial-rib/hoop-cable reflector construction to stretch metal mesh and to satisfy the required surface accuracy. The deployment mechanism employs most of the LDR technology developed for JAXA's ETS-VIII satellite, which was launched in December 2006, and both of the two antennas on the ETS-VIII deployed successfully on orbit. Some prototype models of one module have been made to investigate the surface accuracy. In addition, the antenna will have a two-axis adjustment mechanism for the main reflector, and a three-axis adjustment mechanism for the sub-reflector in order to optimize the antenna gain after deployment in orbit.

  17. Technology Status and the Future of Large Deployable Antennas

    Science.gov (United States)

    Meguro, Akira; Harada, Satoshi; Ishikawa, Hironori; Tsunoda, Hiroaki; Watanabe, Mitsunobu; Mizuno, Hideki

    2002-01-01

    the number of cables in the conventional S-band antenna reflector. An equilibrium shape analysis confirms that the surface error of better than 0.4 mmRMS can be achieved. reliability in defining the difficulty index of ground deployment testing for large deployable antennas. The relationship between the index value and the accuracy of results from ground deployment testing has been estimated by deployment testing of a simple deployment truss structure under both full and micro- gravity conditions. We found that the deployment reliability of a deployable structure can not be evaluated with adequate accuracy if its size exceeds 10 m.The structure must be divided into modules ofappropriate size. Basic studies on inflatable structures and flexible patch elements for future large aperture, sophisticated direct radiation array antennas are underway. Inflatable structures, which consist of rigidized materials and flexible patch elements for feed elements, are interesting candidates. In addition to these studies, distributed sensor/actuator location, non-linear vibration control method, and optimum design methods are also being addressed. They are key technologies for high performance, highly stable, and re-configurable antenna systems.

  18. Highly Accurate Photogrammetric Measurements of the Planck Reflectors

    Science.gov (United States)

    Amiri Parian, J.; Gruen, Armin; Cozzani, Alessandro

    2006-06-01

    The Planck mission of the European Space Agency (ESA) is designed to image the anisotropies of the Cosmic Background Radiation Field over the whole sky. To achieve this aim, sophisticated reflectors are used as part of the Planck telescope receiving system. The system consists of secondary and primary reflectors which are sections of two different ellipsoids of revolution with mean diameters of 1 and 1.6 meters. Deformations of the reflectors which influence the optical parameters and the gain of receiving signals are investigated in vacuum and at very low temperatures. For this investigation, among the various high accuracy measurement techniques, photogrammetry was selected. With respect to the photogrammetric measurements, special considerations had to be taken into account in design steps, measurement arrangement and data processing to achieve very high accuracies. The determinability of additional parameters of the camera under the given network configuration, datum definition, reliability and precision issues as well as workspace limits and propagating errors from different sources are considered. We have designed an optimal photogrammetric network by heuristic simulation for the flight model of the primary and the secondary reflectors with relative precisions better than 1:1000000 and 1:400000 to achieve the requested accuracies. A least squares best fit ellipsoid method was developed to determine the optical parameters of the reflectors. In this paper we will report about the procedures, the network design and the results of real measurements.

  19. Numerical Study of Concentration Characteristics of Linear Fresnel Reflector System

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyun Jin [Kookmin Univ., Seoul (Korea, Republic of); Kim, Jong Kyu; Lee, Sang Nam [Korea Institute of Energy Research, Daejeon (Korea, Republic of)

    2015-12-15

    In this study, we numerically investigated the concentration characteristics of a linear Fresnel reflector system that can drive a solar thermal absorption refrigeration system to be installed in Saudi Arabia. Using an optical modeling program based on the Monte Carlo ray-tracing method, we simulated the concentrated solar flux, concentration efficiency, and concentrated solar energy on four representative days of the year - the vernal equinox, summer solstice, autumnal equinox, and winter solstice. Except the winter solstice, the concentrations were approximately steady from 9 AM to 15 PM, and the concentration efficiencies exceed 70%. Moreover, the maximum solar flux around the solar receiver center changes only within the range of 13.0 - 14.6 kW/m{sup 2}. When we investigated the effects of the receiver installation height, reflector width, and reflector gap, the optimal receiver installation height was found to be 5 m. A smaller reflector width had a greater concentration efficiency. However, the design of the reflector width should be based on the capacity of the refrigeration system because it dominantly affects the concentrated solar energy. The present study was an essential prerequisite for thermal analyses of the solar receiver. Thus, an optical-thermal integration study in the future will assist with the performance prediction and design of the entire system.

  20. Application of the OPTEX method for computing reflector parameters

    Energy Technology Data Exchange (ETDEWEB)

    Hebert, A. [Ecole Polytechnique de Montreal, C.P. 6079 suce. Centre-Ville, Montreal QC. H3C 3A7 (Canada); Leroyer, H. [EDF - R and D, SINETICS, 1 Avenue du General de Gaulle, 92141 Clamart (France)

    2013-07-01

    We are investigating the OPTEX reflector model for obtaining few-group reflector parameters consistent with a reference power distribution in the core. In our study, the reference power distribution is obtained using a 142,872-region calculation defined over a 2D eighth-of-core pressurized water reactor and performed with the method of characteristics. The OPTEX method is based on generalized perturbation theory and uses an optimization algorithm known as parametric linear complementarity pivoting. The proposed model leads to few-group diffusion coefficients or P1-weighted macroscopic total cross sections that can be used to represent the reflector in full-core calculations. These few-group parameters can be spatially heterogeneous in order to correctly represent steel baffles present in modern pressurized water reactors. The optimal reflector parameters are compared to those obtained with a flux-volume weighting of the reflector cross sections recovered from the reference calculation. Important improvements in full-core power distribution are observed when the optimal parameters are used. (authors)

  1. Thermally stable deployable structure

    Science.gov (United States)

    Kegg, Colleen M.

    1988-01-01

    A deployable structure which meets stringent thermal and strength requirements in a space environment was developed. A mast with a very low coefficient of thermal expansion (CTE) was required to limit the movement from thermal distortion over the temperature range of -200 C to 80 C to .064 cm (.025 in). In addition, a high bending strength over the temperature range and weight less than 18.1 kg (40 lbs) was needed. To meet all of the requirements, a composite, near-zero CTE structure was developed. The measured average CTE over the temperature range for the mast was .70 x .000001/C (.38 x .000001/F). The design also has the advantage of being adjustable to attain other specific CTE if desired.

  2. Forward Deployed Robotic Unit

    Science.gov (United States)

    Brendle, Bruce E., Jr.; Bornstein, Jonathan A.

    2000-07-01

    Forward Deployed Robotic Unit (FDRU) is a core science and technology objective of the US Army, which will demonstrate the impact of autonomous systems on all phases of future land warfare. It will develop, integrate and demonstrate technology required to achieve robotic and fire control capabilities for future land combat vehicles, e.g., Future Combat Systems, using a system of systems approach that culminates in a field demonstration in 2005. It will also provide the required unmanned assets and conduct the demonstration. Battle Lab Warfighting Experiments and data analysis required to understand the effects of unmanned assets on combat operations. The US Army Tank- Automotive & Armaments Command and the US Army Research Laboratory are teaming in an effort to leverage prior technology achievements in the areas of autonomous mobility, architecture, sensor and robotics system integration; advance the state-of-the-art in these areas; and to provide field demonstration/application of the technologies.

  3. Complex Deployed Responsive Service

    Science.gov (United States)

    Parry, Glenn; McLening, Marc; Caldwell, Nigel; Thompson, Rob

    A pizza restaurant must provide product, in the form of the food and drink, and service in the way this is delivered to the customer. Providing this has distinct operational challenges, but what if the restaurant also provides a home delivery service? The service becomes deployed as the customer is no-longer co-located with the production area. The business challenge is complicated as service needs to be delivered within a geographic region, to time or the pizza will be cold, and within a cost that is not ­prohibitive. It must also be responsive to short term demand; needing to balance the number of staff it has available to undertake deliveries against a forecast of demand.

  4. Deployable Pipe-Z

    Science.gov (United States)

    Zawidzki, Machi

    2016-10-01

    This paper presents a concept of deployable Pipe-Z (dPZ): a modular structural system which takes advantage of the robustness of rigid-panel mechanism and allows to create free-form links which are also reconfigurable and deployable. The concept presented can be applied for building habitats and infrastructures for human exploration of oceans and outer space. dPZ structures can adapt to changing requirements e.g. mission objectives, crew condition and technological developments. Furthermore, such lightweight and adaptable structural concept can assist in sustainable exploration development. After brief introduction, the concept of Pipe-Z (PZ) is presented. Next, the reconfigurability of PZ is explained and illustrated with continuous and collision-free transition from a PZ forming a Trefoil knot to a Figure-eight knot. The following sections introduce, explain and illustrate the folding mechanism of a single foldable Pipe-Z module (fPZM) and entire dPZ structure. The latter is illustrated with asynchronous (delayed) unfolding of a relatively complex Unknot. Several applications of PZ are suggested, namely for underwater and deep-space and surface habitats, for permanent, but in particular, temporary or emergency passages. As an example, a scenario of a failure of one of the modules of the International Space Station is presented where a rigid structure of 40 fPZMs bypasses the "dead link". A low-fidelity prototype of a 6-module octagonal dPZ is presented; several folding schemes including concentric toric rings are demonstrated. Practical issues of pressurization and packing are briefly discussed.

  5. A Deployable 4 Meter 180 to 680 GHz Antenna for the Scanning Microwave Limb Sounder

    Science.gov (United States)

    Cofield, Richard E.; Cohen, Eri J.; Agnes, Gregory S.; Stek, Paul C.; Livesey, Nathaniel J.; Read, William G.; Thomson, Mark W.; Kasl, Eldon

    2011-01-01

    The Scanning Microwave Limb Sounder (SMLS) is a space-borne heterodyne radiometer which will measure pressure, temperature and atmospheric constituents from thermal emission between 180 and 680 GHz. SMLS, planned for the Global Atmospheric Composition Mission of the NRC Decadal Survey, uses a novel toric Cassegrain antenna to perform both elevation and azimuth scanning. These provide better horizontal and temporal resolution and coverage than were possible with elevation-only scanning at typical Low-Earth orbit spacing in the two previous MLS satellite instruments. Development of the SMLS antenna was the focus of a 2006 Small Business Innovative Research (SBIR) program whose phase II culminated in the fabrication and thermal stability testing of a composite demonstration model of the SMLS primary reflector. This reflector has the full 4m height and 1/3 the width planned for flight. An Instrument Incubator Program (IIP) titled "A deployable 4 Meter 180 to 680 GHz antenna for the Scanning Microwave Limb Sounder" continues development of the SMLS antenna with the study of 5 topics: 1) detailed mathematical modeling of the antenna patterns from which we simulate geophysical parameter retrievals in order to establish FOV performance requirements; 2) thorough correlation of finite element model predictions with measurements made on the SBIR reflector. We will again measure deformations of this reflector, under more flight-like thermal gradients, using higher precision metrology techniques available in a new large-aperture facility at JPL; 3) fabrication of a full-width primary reflector whose asbuilt surface figure will better meet the figure requirements of SMLS than did the SBIR reflector; 4) integration of the primary with other reflectors, and with residual front ends built in a 2007 IIP, in a breadboard antenna; and finally 5) RF testing of the breadboard on a Near Field Range at JPL. We report on significant progress in 3 areas of the current IIP: development of

  6. CMS software deployment on OSG

    Energy Technology Data Exchange (ETDEWEB)

    Kim, B; Avery, P [University of Florida, Gainesville, FL 32611 (United States); Thomas, M [California Institute of Technology, Pasadena, CA 91125 (United States); Wuerthwein, F [University of California at San Diego, La Jolla, CA 92093 (United States)], E-mail: bockjoo@phys.ufl.edu, E-mail: thomas@hep.caltech.edu, E-mail: avery@phys.ufl.edu, E-mail: fkw@fnal.gov

    2008-07-15

    A set of software deployment tools has been developed for the installation, verification, and removal of a CMS software release. The tools that are mainly targeted for the deployment on the OSG have the features of instant release deployment, corrective resubmission of the initial installation job, and an independent web-based deployment portal with Grid security infrastructure login mechanism. We have been deploying over 500 installations and found the tools are reliable and adaptable to cope with problems with changes in the Grid computing environment and the software releases. We present the design of the tools, statistics that we gathered during the operation of the tools, and our experience with the CMS software deployment on the OSG Grid computing environment.

  7. KuDGR- Dual Gridded Carbon Fiber Reinforced Plastic Reflector

    Science.gov (United States)

    Ihle, Alexander; Reichmann, O.; Lori, M.; Nathrath, N.; Pereira, C.; Linke, S.; Rinous, P.

    2014-06-01

    In the frame of an ESA-funded TRP activity HPS GmbH, together with INVENT GmbH and INEGI, has developed an advanced concept for dual gridded reflectors. The target frequency band is the Ku-band requiring high in-orbit thermo-elastic stability. It is a follow-on of the previous KaDGR [1] activity. The concept concerns the polarisation grid of the front and rear reflector. The grids are connected by a full CFRP monolithic peripheral ring. The demonstrator has an overall diameter of 1.4 x 1.2 m and a weight of only 4.23 kg. The design of this concept allows for smaller and larger reflectors.In the following we will present the results of the different development steps and current status of the TRP activity.

  8. Square Van Atta reflector with conducting mounting flame

    DEFF Research Database (Denmark)

    Nielsen, Erik Dragø

    1970-01-01

    the antenna elements and the reradiation from the elements as well as from the conducting plate have been taken into account. The influence of the conducting plate on the induced dipole currents has been treated using the theory of images. The scattering cross section of Van Atta reflectors with or without......A theoretical and numerical analysis of square Van Atta reflectors has been carried out with or without a conducting plate, used for mounting of the antenna elements. The Van Atta reflector investigated has antenna elements which are parallel half-wave dipoles interconnected in pairs...... by transmission lines of equal electrical length. The dipoles are placed in a plane which is parallel to the conducting plate when this is present. In the theory, each pair of antenna elements with the interconnecting transmission line is represented by an equivalent circuit. The mutual impedance between...

  9. Semitransparent Polymer Solar Cells Based on Liquid Crystal Reflectors

    Directory of Open Access Journals (Sweden)

    Shaopeng Yang

    2014-01-01

    Full Text Available The effects of liquid crystal (LC reflectors on semitransparent polymer solar cells (PSCs were investigated in this paper. By improving the cathode, we manufactured semitransparent PSCs based on the conventional PSCs. We then incorporated the LC reflector into the semitransparent PSCs, which increased the power conversion efficiency (PCE from 2.11% to 2.71%. Subsequently adjusting the concentration and spinning speed of the active layer material changed its thickness. The maximum light absorption for the active layer was obtained using the optimum thickness, and the PCE eventually reached 3.01%. These results provide a reference for selecting LC reflectors that are suitable for different active layer materials to improve the PCE of semitransparent PSCs.

  10. An active reflector antenna using a laser angle metrology system

    Institute of Scientific and Technical Information of China (English)

    Yong Zhang; Jie Zhang; De-Hua Yang; Guo-Hua Zhou; Ai-Hua Li; Guo-Ping Li

    2012-01-01

    An active reflector is one of the key technologies for constructing large telescopes,especially for millimeter/sub-millimeter radio telescopes.This article introduces a new efficient laser angle metrology system for an active reflector antenna on large radio telescopes.Our experiments concentrate on developing an active reflector for improving the detection precisions and the maintenance of the surface shape in real time on the 65-meter prototype radio telescope constructed by Nanjing Institute of Astronomical Optics and Technology (NIAOT; http://65m.shao.cas.cn/).The test results indicate that the accuracy of the surface shape segmentation and maintenance has the dimensions of microns,and the time-response can be on the order of minutes.Our efforts proved to be workable for sub-millimeter radio telescopes.

  11. Family Reintegration Following Guard Deployment

    Science.gov (United States)

    2010-09-20

    expectations is a key process that has to occur for successful reintegration of the veteran back into the family. Both parties have to work out their...describe veterans and families perceptions of: Aim 1. Their experience with family reintegration and the challenges reintegration presents; Aim 2...deployment, and post deployment shape the degree of challenges with reintegration that a veteran and their family will encounter. Pre-deployment, the

  12. Design optimization of deployable wings

    Science.gov (United States)

    Gaddam, Pradeep

    Morphing technology is an important aspect of UAV design, particularly in regards to deployable systems. The design of such system has an important impact on the vehicle's performance. The primary focus of the present research work was to determine the most optimum deployable wing design from 3 competing designs and develop one of the deployable wing designs to test in the research facility. A Matlab code was developed to optimize 3 deployable wing concepts inflatable, inflatable telescopic and rigid-folding wings based on a sequential optimization strategy. The constraints that were part of the code include the packaging constraints during its stowed state, fixed length of the deployed section and the minimum L/D constraint. This code resulted in determining the optimum weight of all the 3 designs, the most optimum weight design is the inflatable wing design. This is a result of the flexible skin material and also due to no rigid parts in the deployed wing section. Another goal of the research involved developing an inflatable telescopic wing. The prototype was tested in a wind tunnel, while the actual wing was tested in the altitude chamber to determine the deployment speed, input pressure, analyze and predict the deployment sequence and behavior of the wing at such high wind speeds and altitudes ranging from 60,000 ft to 90,000 ft. Results from these tests allowed us to conclude the deployment sequence of the telescopic wing followed from the root to the tip section. The results were used to analyze the deployment time of the wing. As expected the deployment time decreased with an increase in input pressure. The results also show us that as the altitude increases, the deployment speed of the wing also increased. This was demonstrated when the wing was tested at a maximum altitude pressure of 90,000ft, well above the design altitude of 60,000ft.

  13. Effect of phototherapy with alumunium foil reflectors on neonatal hyperbilirubinemia

    Directory of Open Access Journals (Sweden)

    Tony Ijong Dachlan

    2016-07-01

    Full Text Available Background Neonatal hyperbilirubinemia (NH is one of the most common problems in neonates, but it can be treated with blue light phototherapy. Developing countries with limited medical equipment and funds have difficulty providing effective phototherapy to treat NH, leading to increased risk of bilirubin encephalopathy. Phototherapy with white reflecting curtains can decrease the duration of phototherapy needed to reduce bilirubin levels. Objective To compare the duration of phototherapy needed in neonates with NH who underwent phototherapy with and without aluminum foil reflectors. Methods This open clinical trial was conducted from July to August 2013 at Dr. Hasan Sadikin Hospital, Bandung, Indonesia. The inclusion criteria were term neonates with uncomplicated NH presenting in their first week of life. Subjects were randomized into two groups, those who received phototherapy with or without aluminum foil reflectors. Serum bilirubin is taken at 12th, 24th, 48th hours, then every 24 hours if needed until phototherapy can be stopped according to American Academy of Pediatrics guidelines. The outcome measured was the duration of phototherapy using survival analysis. The difference between the two groups was tested by Gehan method. Results Seventy newborns who fulfilled the inclusion criteria and had similar characteristics were randomized into two groups. The duration of phototherapy needed was significantly less in the group with aluminum foil reflectors than in the group without reflectors [72 vs. 96 hours, respectively, (P<0.01]. Conclusion The required duration of phototherapy with aluminum foil reflectors is significantly less than that of phototherapy without reflectors, in neonates with NH.

  14. Mastering Hyper-V Deployment

    CERN Document Server

    Finn, Aidan

    2010-01-01

    The only book to take an in-depth look at deploying Hyper-V. Now in its second generation, the popular Hyper-V boasts technical advances that create even more dynamic systems than ever before. This unique resource serves an authoritative guide to deploying Windows Server 2008 R2 Hyper-V comprehensively. Step-by-step instructions demonstrate how to design a Hyper-V deployment, build a Hyper-V host environment, and design a management system with System Center Virtual Machine Manager 2008 R2.: Features real-world examples that show you how to design a Hyper-V deployment, build a Hyper-V host env

  15. Infrastructure Engineering and Deployment Division

    Data.gov (United States)

    Federal Laboratory Consortium — Volpe's Infrastructure Engineering and Deployment Division advances transportation innovation by being leaders in infrastructure technology, including vehicles and...

  16. A better trihedral corner reflector for low grazing angles

    Science.gov (United States)

    Doerry, A. W.; Brock, B. C.

    2012-06-01

    Trihedral corner reflectors are the preferred canonical target for SAR performance evaluation for many radar development programs. The conventional trihedrals have problems with substantially reduced Radar Cross Section (RCS) at low grazing angles, unless they are tilted forward, but in which case other problems arise mainly due to multipath effects. Consequently there is a need for better low grazing angle performance for trihedrals. This is facilitated by extending the bottom plate of the trihedral reflector. A relevant analysis of RCS for an infinite ground plate is presented. Practical aspects are also discussed.

  17. Recent Developments of Reflectarray Antennas in Dual-Reflector Configurations

    Directory of Open Access Journals (Sweden)

    Carolina Tienda

    2012-01-01

    Full Text Available Recent work on dual-reflector antennas involving reflectarrays is reviewed in this paper. Both dual-reflector antenna with a reflectarray subreflector and dual-reflectarrays antennas with flat or parabolic main reflectarray are considered. First, a general analysis technique for these two configurations is described. Second, results for beam scanning and contoured-beam applications in different frequency bands are shown and discussed. The performance and capabilities of these antennas are shown by describing some practical design cases for radar, satellite communications, and direct broadcast satellite (DBS applications.

  18. Lunar Eclipse Observations Reveal Anomalous Thermal Performance of Apollo Reflectors

    CERN Document Server

    Murphy, T W; Johnson, N H; Goodrow, S D

    2013-01-01

    Laser ranging measurements during the total lunar eclipse on 2010 December 21 verify previously suspected thermal lensing in the retroreflectors left on the lunar surface by the Apollo astronauts. Signal levels during the eclipse far exceeded those historically seen at full moon, and varied over an order of magnitude as the eclipse progressed. These variations can be understood via a straightforward thermal scenario involving solar absorption by a ~50% covering of dust that has accumulated on the front surfaces of the reflectors. The same mechanism can explain the long-term degradation of signal from the reflectors as well as the acute signal deficit observed near full moon.

  19. Tensile-strained germanium microdisks with circular Bragg reflectors

    Science.gov (United States)

    El Kurdi, M.; Prost, M.; Ghrib, A.; Elbaz, A.; Sauvage, S.; Checoury, X.; Beaudoin, G.; Sagnes, I.; Picardi, G.; Ossikovski, R.; Boeuf, F.; Boucaud, P.

    2016-02-01

    We demonstrate the combination of germanium microdisks tensily strained by silicon nitride layers and circular Bragg reflectors. The microdisks with suspended lateral Bragg reflectors form a cavity with quality factors up to 2000 around 2 μm. This represents a key feature to achieve a microlaser with a quasi-direct band gap germanium under a 1.6% biaxial tensile strain. We show that lowering the temperature significantly improves the quality factor of the quasi-radial modes. Linewidth narrowing is observed in a range of weak continuous wave excitation powers. We finally discuss the requirements to achieve lasing with these kind of structures.

  20. New Developments in Large High Performance Shaped Reflectors

    Science.gov (United States)

    Abegg, C.; Baril, S.

    2002-01-01

    The large shaped reflectors, currently designed and manufactured at EADS LAUNCH VEHICLES, belong to a new generation of highly precise, highly stable and low mass reflectors for C/Ku-band and up to Ka-band missions. The previous EADS LAUNCH VEHICLES flight proven design was the one presented in the past at IAF and especially in 1994 and 1995, which was already at his time the in-orbit largest (3.5m x 2.6m) rigid reflector in the world for C/Ku-band missions. Operators require higher and higher performances for telecommunication antenna. And since the antenna performances are very dependent on the reflector ones, several developments of a new generation of large shaped reflectors started in the late 1990's. The first development consists in a new concept which particularly enhances the manufacturing easiness, the manufacturing distortion performances, the in-orbit distortion performances, the mass, the versatility versus a late change of coverage and versus implementation on different platforms. An extensive qualification test campaign has been successfully achieved in 2001, with outstanding performances: 30% mass gain and 50% gain of manufacturing and in-orbit accuracy with respect to previous 1995's design for the largest 3.5m x 2.6m reflectors. In parallel, developments have been led at EADS LAUNCH VEHICLES for large Ka-band mission antenna reflectors. These developments include single and dual shell reflectors with diameters up to 1.8 m. Furthermore, antenna requirements have recently led to more and more shaped profiles to fulfil RF needs. EADS LAUNCH VEHICLES has then started a development to verify the capability to manufacture very small curvature radius around 30mm, in order to provide the best product for the satellite missions. All the necessary analyses and material/processes characterisation tests have been carried out for these developments. Qualification tests have been performed or are under progress in profile measurements, sine vibration, acoustic

  1. Lunar eclipse observations reveal anomalous thermal performance of Apollo reflectors

    Science.gov (United States)

    Murphy, T. W.; McMillan, R. J.; Johnson, N. H.; Goodrow, S. D.

    2014-03-01

    Laser ranging measurements during the total lunar eclipse on 2010 December 21 verify previously suspected thermal lensing in the retroreflectors left on the lunar surface by the Apollo astronauts. Signal levels during the eclipse far exceeded those historically seen at full moon, and varied over an order of magnitude as the eclipse progressed. These variations can be understood via a straightforward thermal scenario involving solar absorption by a ∼50% covering of dust that has accumulated on the front surfaces of the reflectors. The same mechanism can explain the long-term degradation of signal from the reflectors as well as the acute signal deficit observed near full moon.

  2. Highly Enriched Uranium Metal Cylinders Surrounded by Various Reflector Materials

    Energy Technology Data Exchange (ETDEWEB)

    Bernard Jones; J. Blair Briggs; Leland Monteirth

    2007-05-01

    A series of experiments was performed at Los Alamos Scientific Laboratory in 1958 to determine critical masses of cylinders of Oralloy (Oy) reflected by a number of materials. The experiments were all performed on the Comet Universal Critical Assembly Machine, and consisted of discs of highly enriched uranium (93.3 wt.% 235U) reflected by half-inch and one-inch-thick cylindrical shells of various reflector materials. The experiments were performed by members of Group N-2, particularly K. W. Gallup, G. E. Hansen, H. C. Paxton, and R. H. White. This experiment was intended to ascertain critical masses for criticality safety purposes, as well as to compare neutron transport cross sections to those obtained from danger coefficient measurements with the Topsy Oralloy-Tuballoy reflected and Godiva unreflected critical assemblies. The reflector materials examined in this series of experiments are as follows: magnesium, titanium, aluminum, graphite, mild steel, nickel, copper, cobalt, molybdenum, natural uranium, tungsten, beryllium, aluminum oxide, molybdenum carbide, and polythene (polyethylene). Also included are two special configurations of composite beryllium and iron reflectors. Analyses were performed in which uncertainty associated with six different parameters was evaluated; namely, extrapolation to the uranium critical mass, uranium density, 235U enrichment, reflector density, reflector thickness, and reflector impurities. In addition to the idealizations made by the experimenters (removal of the platen and diaphragm), two simplifications were also made to the benchmark models that resulted in a small bias and additional uncertainty. First of all, since impurities in core and reflector materials are only estimated, they are not included in the benchmark models. Secondly, the room, support structure, and other possible surrounding equipment were not included in the model. Bias values that result from these two simplifications were determined and associated

  3. An Optical Reflector System for the CANGAROO-II Telescope

    CERN Document Server

    Kawachi, A

    1999-01-01

    We have developed light and durable mirrors made of CFRP (Carbon Fiber Reinforced Plastics) laminates for the reflector of the new CANGAROO-II 7 m telescope. The reflector has a parabolic shape (F/1.1) with a 30 m^2 effective area which consists of 60 small spherical mirrors. The attitude of each mirror can be remotely adjusted by stepping motors. After the first adjustment work, the re ector offers a point image of about 0.14 degree (FWHM) on the optic axis. The telescope has been in operation since May 1999 with an energy threshold of ~ 300 GeV.

  4. Deployable Fresnel Rings

    Science.gov (United States)

    Kennedy, Timothy F.; Fink, Patrick W.; Chu, Andrew W.; Lin, Gregory Y.

    2014-01-01

    Deployable Fresnel rings (DFRs) significantly enhance the realizable gain of an antenna. This innovation is intended to be used in combination with another antenna element, as the DFR itself acts as a focusing or microwave lens element for a primary antenna. This method is completely passive, and is also completely wireless in that it requires neither a cable, nor a connector from the antenna port of the primary antenna to the DFR. The technology improves upon the previous NASA technology called a Tri-Sector Deployable Array Antenna in at least three critical aspects. In contrast to the previous technology, this innovation requires no connector, cable, or other physical interface to the primary communication radio or sensor device. The achievable improvement in terms of antenna gain is significantly higher than has been achieved with the previous technology. Also, where previous embodiments of the Tri-Sector antenna have been constructed with combinations of conventional (e.g., printed circuit board) and conductive fabric materials, this innovation is realized using only conductive and non-conductive fabric (i.e., "e-textile") materials, with the possible exception of a spring-like deployment ring. Conceptually, a DFR operates by canceling the out-of-phase radiation at a plane by insertion of a conducting ring or rings of a specific size and distance from the source antenna, defined by Fresnel zones. Design of DFRs follow similar procedures to those outlined for conventional Fresnel zone rings. Gain enhancement using a single ring is verified experimentally and through computational simulation. The experimental test setup involves a microstrip patch antenna that is directly behind a single-ring DFR and is radiating towards a second microstrip patch antenna. The first patch antenna and DFR are shown. At 2.42 GHz, the DFR improves the transmit antenna gain by 8.6 dB, as shown in Figure 2, relative to the wireless link without the DFR. A figure illustrates the

  5. Electrical performance verification methodology for large reflector antennas: based on the P-band SAR payload of the ESA BIOMASS candidate mission

    DEFF Research Database (Denmark)

    Pivnenko, Sergey; Kim, Oleksiy S.; Nielsen, Jeppe Majlund;

    2013-01-01

    In this paper, an electrical performance verification methodology for large reflector antennas is proposed. The verification methodology was developed for the BIOMASS P-band (435 MHz) synthetic aperture radar (SAR), but can be applied to other large deployable or fixed reflector antennas for which...... the verification of the entire antenna or payload is impossible. The two-step methodology is based on accurate measurement of the feed structure characteristics, such as complex radiation pattern and radiation efficiency, with an appropriate Measurement technique, and then accurate calculation of the radiation...... pattern and gain of the entire antenna including support and satellite structure with an appropriate computational software. A preliminary investigation of the proposed methodology was carried out by performing extensive simulations of different verification approaches. The experimental validation...

  6. Analysis of the Thermo-Elastic Response of Space Reflectors to Simulated Space Environment

    Science.gov (United States)

    Allegri, G.; Ivagnes, M. M.; Marchetti, M.; Poscente, F.

    2002-01-01

    high pressure Xenon lamps to simulate the direct solar irradiation and a cryogenic heat exchanger to reproduce the earth shadowing of sunlight. The temperature of the thermal cycles ranges from -80°C up to 100°C: the thermo-elastic response of the antenna has been surveyed by employing strain gauges place on the structures at several different locations. The structure has been subjected to 100 thermal cycles, each of which lasting two hours: the total duration of the exposition to the vacuum environment has been equal to 300 hours. Finally the antenna has been disassembled and its elements have been examined to evaluate the effects of the simulated exposition on each of them: the total mass loss and the final thermo-mechanical properties of the polymeric based materials which constitute the structural core of the antenna have been surveyed. The experimental results have been compared to numerical simulation performed by the NASTRAN code: the basic FEM model, developed for the unexposed antenna, has been updated to take into account the thermo-mechanical degradation of the structural elements and materials. This has allowed to obtain, by extrapolation, a FEM based prevision of the antenna thermo-elastic response for long-term operative conditions. References. [1] D. Hastings, H. Garret "Spacecraft environment interactions", Cambridge University Press, Atmospheric Series, Cambridge, 1996. [2] IAF-01-I.6.05 "On the Reliability of Honeycomb Core Bonding Joint in Sandwich Composite Materials for Space Applications" G. Allegri, U. Lecci, M. Marchetti, F. Poscente, 52° IAF Congress, 2001. [3] Meguro A. and alii, "Technology status of the 13 m aperture deployment antenna reflectors for Engineering Test Satellite VIII", Acta Astronautica, Volume: 47, Issue: 2-9, July - November, 2000, pp. 147-152. [4] Novikov L. S. "Contemporary state of spacecraft/environment interaction research" Radiation Measurements, Volume: 30, Issue: 5, October, 1999, pp. 661-667. [5] IAF-01-I.1

  7. Device Measures Angle Of Deployment

    Science.gov (United States)

    Jermakian, Joel B.

    1991-01-01

    Simple electromechanical device indicates angular position of unfolding panel during and after deployment. Resistance of potentiometer gradually increases as unfolding of solar panel about hinge moves wiper of potentiometer. At full deployment, panel pushes and opens normally closed switch. Designed for use on panel of solar photovoltaic cells in spacecraft, modified for use in other, similar position-indicating applications.

  8. Strategic Sealift Supporting Army Deployments

    Science.gov (United States)

    2016-06-10

    STRATEGIC SEALIFT SUPPORTING ARMY DEPLOYMENTS A thesis presented to the Faculty of the U.S. Army Command and General Staff...THOMPSON, MAJ, US ARMY BFA, Louisiana Tech University, Ruston, Louisiana, 1994 Fort Leavenworth, Kansas 2016 Approved for...Strategic Sealift Supporting Army Deployments 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Matthew

  9. Semitransparent organic solar cells with organic wavelength dependent reflectors

    NARCIS (Netherlands)

    Galagan, Y.O.; Debije, M.G.; Blom, P.W.M.

    2011-01-01

    Semitransparent organic solar cells employing solution-processable organic wavelength dependent reflectors of chiral nematic (cholesteric) liquid crystals are demonstrated. The cholesteric liquid crystal (CLC) reflects only in a narrow band of the solar spectrum and remains transparent for the remai

  10. Advanced reflector characterization with ultrasonic phased arrays in NDE applications.

    Science.gov (United States)

    Wilcox, Paul D; Holmes, Caroline; Drinkwater, Bruce W

    2007-08-01

    Ultrasonic arrays are increasingly widely used in nondestructive evaluation (NDE) due to their greater flexibility and potentially superior performance compared to conventional monolithic probes. The characterization of small defects remains a challenge for NDE and is of great importance for determining the impact of a defect on the integrity of a structure. In this paper, a technique for characterizing reflectors with subwavelength dimensions is described. This is achieved by post-processing the complete data set of time traces obtained from an ultrasonic array using two algorithms. The first algorithm is used to obtain information about reflector orientation and the second algorithm is used to distinguish between point-like reflectors that reflect uniformly in all directions and specular reflectors that have distinct orientations. Experimental results are presented using a commercial 64-element, 5-MHZ array on two aluminum test specimens that contain a number of machined slots and side-drilled holes. The results show that the orientation of 1-mm-long slots can be determined to within a few degrees and that the signals from 1-mm-long slots can be distinguished from that from a 1-mm-diameter circular hole. Techniques for quantifying both the orientation and the specularity of measured signals are presented and the effect of processing parameters on the accuracy of results is discussed.

  11. Large-scale Optimization of Contoured Beam Reflectors and Reflectarrays

    DEFF Research Database (Denmark)

    Borries, Oscar; Sørensen, Stig B.; Jørgensen, Erik;

    2016-01-01

    Designing a contoured beam reflector or performing a direct optimization of a reflectarray requires a mathematical optimization procedure to determine the optimum design of the antenna. A popular approach, used in the market-leading TICRA software POS, can result in computation times on the order...

  12. Consequences of nonorthogonality on the scattering properties of dihedral reflectors

    Science.gov (United States)

    Anderson, W. C.

    1987-10-01

    Small deviations from orthogonality can reduce drastically the backscattering radar cross section (RCS) of dihedral corner reflectors. The method of physical optics is used to calculate the magnitude of the reductions in RCS which result from modest departures from orthogonality. The theoretical results are then compared with experimental measurements which are found to be in very good agreement.

  13. Classification of Surface Quality of Automobile Lamp—Reflector

    Institute of Scientific and Technical Information of China (English)

    袁旭军; 贺莉清; 等

    2002-01-01

    This paper introduces an installation for quickly classifying automobile's metal reflectors based on their roughness.The measuring principle and the mechanical structure are presented.Schematics of circuits and experimental results are given.Elimination and reduction of the effect of background lights or different bulbs on the measuring results are also described in detail.

  14. Leaky Wave Enhanced Feeds for Multi-Beam Reflector Systems

    NARCIS (Netherlands)

    Neto, A.; Gerini, G.; Llombart, N.; Ettorre, M.; Maagt, P. de

    2011-01-01

    Abstract—This paper discusses the use of dielectric superlayers to shape the radiation pattern of focal plane feeds of a multi-beam reflector system. The shaping of the pattern is obtained by exciting a pair (TE/TM) of leaky waves that radiate incrementally as they propagate between the ground plane

  15. Optical Phased Array Using Guided Resonance with Backside Reflectors

    Science.gov (United States)

    Horie, Yu (Inventor); Arbabi, Amir (Inventor); Faraon, Andrei (Inventor)

    2016-01-01

    Methods and systems for controlling the phase of electromagnetic waves are disclosed. A device can consist of a guided resonance grating layer, a spacer, and a reflector. A plurality of devices, arranged in a grid pattern, can control the phase of reflected electromagnetic phase, through refractive index control. Carrier injection, temperature control, and optical beams can be applied to control the refractive index.

  16. Step-Stress Accelerated Degradation Testing for Solar Reflectors: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Jones, W.; Elmore, R.; Lee, J.; Kennedy, C.

    2011-09-01

    To meet the challenge to reduce the cost of electricity generated with concentrating solar power (CSP) new low-cost reflector materials are being developed including metalized polymer reflectors and must be tested and validated against appropriate failure mechanisms. We explore the application of testing methods and statistical inference techniques for quantifying estimates and improving lifetimes of concentrating solar power (CSP) reflectors associated with failure mechanisms initiated by exposure to the ultraviolet (UV) part of the solar spectrum. In general, a suite of durability and reliability tests are available for testing a variety of failure mechanisms where the results of a set are required to understand overall lifetime of a CSP reflector. We will focus on the use of the Ultra-Accelerated Weathering System (UAWS) as a testing device for assessing various degradation patterns attributable to accelerated UV exposure. Depending on number of samples, test conditions, degradation and failure patterns, test results may be used to derive insight into failure mechanisms, associated physical parameters, lifetimes and uncertainties. In the most complicated case warranting advanced planning and statistical inference, step-stress accelerated degradation (SSADT) methods may be applied.

  17. Frequency Selective Surfaces for extended Bandwidth backing reflector functions

    NARCIS (Netherlands)

    Pasian, M.; Neto, A.; Monni, S.; Ettorre, M.; Gerini, G.

    2008-01-01

    This paper deals with the use of Frequency Selective Surfaces (FSS) to increase the Efficiency × Bandwidth product in Ultra-Wide Band (UWB) antenna arrays whose efficiency is limited by the front-to-back ratio. If the backing reflector is realized in one metal plane solution its location will be sui

  18. Semitransparent organic solar cells with organic wavelength dependent reflectors

    NARCIS (Netherlands)

    Galagan, Y.O.; Debije, M.G.; Blom, P.W.M.

    2011-01-01

    Semitransparent organic solar cells employing solution-processable organic wavelength dependent reflectors of chiral nematic (cholesteric) liquid crystals are demonstrated. The cholesteric liquid crystal (CLC) reflects only in a narrow band of the solar spectrum and remains transparent for the remai

  19. EBG Enhanced Reflector Feeds for Wide Angle Scanning Applications

    NARCIS (Netherlands)

    Neto, A.; Ettorre, M.; Gerini, G.; Maagt, P.J. de

    2008-01-01

    This work is an extension of a series of works on the use of dielectric super-layers to shape the radiation pattern of each feed composing a focal plane imaging array. Using dielectric super-layers, the spill over from the reflectors are reduced without increasing the dimensions of each aperture. Th

  20. Computer program aids dual reflector antenna system design

    Science.gov (United States)

    Firnett, P.; Gerritsen, R.; Jarvie, P.; Ludwig, A.

    1968-01-01

    Computer program aids in the design of maximum efficiency dual reflector antenna systems. It designs a shaped cassegrainian antenna which has nearly 100 percent efficiency, and accepts input parameters specifying an existing conventional antenna and produces as output the modifications necessary to conform to a shaped design.

  1. Beam spoiling a reflector antenna with conducting shim.

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter

    2012-12-01

    A horn-fed dish reflector antenna has characteristics including beam pattern that are a function of its mechanical form. The beam pattern can be altered by changing the mechanical configuration of the antenna. One way to do this is with a reflecting insert or shim added to the face of the original dish.

  2. Application of parabolic reflector on Raman analysis of gas samples

    Science.gov (United States)

    Yu, Anlan; Zuo, Duluo; Gao, Jun; Li, Bin; Wang, Xingbing

    2016-05-01

    Studies on the application of a parabolic reflector in spontaneous Raman scattering for low background Raman analysis of gas samples are reported. As an effective signal enhancing sample cell, photonic bandgap fiber (HC-PBF) or metallined capillary normally result in a strong continuous background in spectra caused by the strong Raman/fluorescence signal from the silica wall and the polymer protective film. In order to obtain enhanced signal with low background, a specially designed sample cell with double-pass and large collecting solid angle constructed by a parabolic reflector and a planar reflector was applied, of which the optical surfaces had been processed by diamond turning and coated by silver film and protective film of high-purity alumina. The influences of optical structure, polarization characteristic, collecting solid-angle and collecting efficiency of the sample cell on light propagation and signal enhancement were studied. A Raman spectrum of ambient air with signal to background ratio of 94 was acquired with an exposure time of 1 sec by an imaging spectrograph. Besides, the 3σ limits of detection (LOD) of 7 ppm for H2, 8 ppm for CO2 and 12 ppm for CO were also obtained. The sample cell mainly based on parabolic reflector will be helpful for compact and high-sensitive Raman system.

  3. Measurement of small antenna reflector losses for radiometer calibration budget

    DEFF Research Database (Denmark)

    Skou, Niels

    1997-01-01

    Antenna reflector losses play an important role in the calibration budget for a microwave radiometer. If the losses are small, they are difficult to measure by traditional means. However, they can be assessed directly by radiometric means using the sky brightness temperature as incident radiation...

  4. Geometrically Nonlinear Finite Element Analysis of a Composite Space Reflector

    Science.gov (United States)

    Lee, Kee-Joo; Leet, Sung W.; Clark, Greg; Broduer, Steve (Technical Monitor)

    2001-01-01

    Lightweight aerospace structures, such as low areal density composite space reflectors, are highly flexible and may undergo large deflection under applied loading, especially during the launch phase. Accordingly, geometrically nonlinear analysis that takes into account the effect of finite rotation may be needed to determine the deformed shape for a clearance check and the stress and strain state to ensure structural integrity. In this study, deformation of the space reflector is determined under static conditions using a geometrically nonlinear solid shell finite element model. For the solid shell element formulation, the kinematics of deformation is described by six variables that are purely vector components. Because rotational angles are not used, this approach is free of the limitations of small angle increments. This also allows easy connections between substructures and large load increments with respect to the conventional shell formulation using rotational parameters. Geometrically nonlinear analyses were carried out for three cases of static point loads applied at selected points. A chart shows results for a case when the load is applied at the center point of the reflector dish. The computed results capture the nonlinear behavior of the composite reflector as the applied load increases. Also, they are in good agreement with the data obtained by experiments.

  5. Quasi-static Deployment Simulation for Deployable Space Truss Structures

    Institute of Scientific and Technical Information of China (English)

    陈务军; 付功义; 何艳丽; 董石麟

    2004-01-01

    A new method was proposed for quasi-static deployment analysis of deployable space truss structures. The structure is assumed a rigid assembly, whose constraints are classified as three categories:rigid member constraint, joint-attached kinematic constraint and boundary constraint. And their geometric constraint equations and derivative matrices are formulated. The basis of the null space and M-P inverse of the geometric constraint matrix are employed to determine the solution for quasi-static deployment analysis. The influence introduced by higher terms of constraints is evaluated subsequently. The numerical tests show that the new method is efficient.

  6. Control of active reflector system for radio telescope

    Science.gov (United States)

    Zhou, Guo-hua; Li, Guo-ping; Zhang, Yong; Zhang, Zhen-chao

    2016-10-01

    According to the control requirements of the active reflector surface in the 110 m radio telescope at QiTai(QTT) Xinjiang, a new displacement actuator and a new displacement control system were designed and manufactured and then their characteristics were tested by a dual-frequency laser interferometer in the micro-displacement laboratory. The displacement actuator was designed by a scheme of high precision worm and roller screw structures, and the displacement control system was based on a ARM micro-processor. Finally, the S curve acceleration control methods were used to design the hardware platform and software algorithm for the active reflection surface of the control system. The test experiments were performed based on the laser metrology system on an active reflector close-loop antenna prototype for large radio telescope. Experimental results indicate that it achieves a 30 mm working stroke and 5 μm RMS motion resolution. The accuracy (standard deviation) is 3.67 mm, and the error between the determined and theoretical values is 0.04% when the rated load is 300 kg, the step is 2 mm and the stroke is 30mm. Furthermore, the active reflector integrated system was tested by the laser sensors with the accuracy of 0.25 μm RMS on 4-panel radio telescope prototype, the measurement results show that the integrated precision of the active reflector closed-loop control system is less than 5 μm RMS, and well satisfies the technical requirements of active reflector control system of the QTT radio telescope in 3 mm wavelength.

  7. Modeling and analysis of deployment dynamics for a novel ring mechanism

    Science.gov (United States)

    Li, Bing; Qi, Xiaozhi; Huang, Hailin; Xu, Wenfu

    2016-03-01

    With the development of satellite-communication and earth-observation technologies, the demands for large and light space-deployable antennas have become more and more urgent. In this paper, a deployable ring mechanism capable of supporting a large flexible cable net antenna reflector is presented. The mechanism is driven by torsion springs and controlled by cables. It is composed of multiple deployable modules and has a high deploy/fold ratio, therefore, it has good application prospects. To improve the reliability of the mechanism, a dynamic simulation must be conducted at the design stage to investigate the mechanical characteristics. First, a full kinematic model is established and the position, velocity, and acceleration of the mechanism are analyzed. Next, taking into account the influence of the flexible cable net, frictional damping and the torsion springs, the deployment dynamics of the mechanism are modeled by using a Lagrange's method. Finally, forward dynamics and inverse dynamics simulations are conducted to investigate the rules the governing system-energy variation, and the influence of viscous damping on the motion of the mechanism. A modified deployment motion planning method based on force-control is proposed, and the relationships between control force and motion are ascertained and verified by a prototype of the ring mechanism.

  8. Deployable Structural Booms for Large Deployable Solar Arrays Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The development of a new generation of large, high power deployable solar arrays has been identified as the most significant challenge facing the development of...

  9. Self deployable deorbiting space structure

    DEFF Research Database (Denmark)

    2012-01-01

    -active or heavy device has to be brought on board the spacecraft for deploying the space structure. Allows the deployed flexible sheet surface higher than the case when SDSS is rigidly linked at the short distance from carrier structure. Ensures a reliable unfolding of deorbiting structures in zero gravity....... Provides the strain energy provoking the deployment without the need of addition of energy to the system. Eliminates the issues around successful unfolding known from other technical solutions as the frame unfolds automatically without using external energy for unfolding by using the accumulated strain...... energy in stressed configuration. Ensures that deorbiting space structure can be efficiently folded without intervention of active unfolding device....

  10. New concepts in deployable beam structures

    Science.gov (United States)

    Rhodes, M. D.

    1985-01-01

    The design of deployable structures involves a complicated tradeoff of packaging efficiency, the overall mechanism associated with deploying and latching beam joints, and the requirements and complexity of the beam deployer/repacker. Three longeron deployable beams, controllable geometry beams, and hybrid deployable/erectable beam concepts are evaluated.

  11. Design of a plasmonic back reflector for silicon nanowire decorated solar cells.

    Science.gov (United States)

    Ren, Rui; Guo, Yongxin; Zhu, Rihong

    2012-10-15

    This Letter presents a crystalline silicon thin film solar cell model with Si nanowire arrays surface decoration and metallic nanostructure patterns on the back reflector. The nanostructured Ag back reflector can significantly enhance the absorption in the near-infrared spectrum. Furthermore, by inserting a ZnO:Al layer between the silicon substrate and nanostructured Ag back reflector, the absorption loss in the Ag back reflector can be clearly depressed, contributing to a maximum J(sc) of 28.4 mA/cm(2). A photocurrent enhancement of 22% is achieved compared with a SiNW solar cell with a planar Ag back reflector.

  12. Differential geodetic stereo SAR with TerraSAR-X by exploiting small multi-directional radar reflectors

    Science.gov (United States)

    Gisinger, Christoph; Willberg, Martin; Balss, Ulrich; Klügel, Thomas; Mähler, Swetlana; Pail, Roland; Eineder, Michael

    2017-01-01

    In this paper, we report on the direct positioning of small multi-directional radar reflectors, so-called octahedrons, with the synthetic aperture radar (SAR) satellite TerraSAR-X. Its highest resolution imaging mode termed staring spotlight enables the use of such octahedron reflectors with a dimension of only half a meter, but still providing backscatter equivalent to 1-2 cm observation error. Four octahedrons were deployed at Wettzell geodetic observatory, and observed by TerraSAR-X with 12 acquisitions in three different geometries. By applying our least squares stereo SAR algorithm already tested with common trihedral corner reflectors (CRs), and introducing a novel differential extension using one octahedron as reference point, the coordinates of the remaining octahedrons were directly retrieved in the International Terrestrial Reference Frame (ITRF). Contrary to our standard processing, the differential approach does not require external corrections for the atmospheric path delays and the geodynamic displacements, rendering it particularly useful for joint geodetic networks employing SAR and GNSS. In this paper, we present and discuss both methods based on results when applying them to the aforementioned Wettzell data set of the octahedrons. The comparison with the independently determined reference coordinates confirms the positioning accuracy with 2-5 cm for the standard approach, and 2-3 cm for the differential processing. Moreover, we present statistical uncertainty estimates of the observations and the positioning solutions, which are additionally provided by our parameter estimation algorithms. The results also include our 1.5 m CR available at Wettzell, and the outcomes clearly demonstrate the advantage of the multi-directional octahedrons over conventional CRs for global positioning applications with SAR.

  13. Theoretical analysis of solar thermal collector and flat plate bottom reflector with a gap between them

    Directory of Open Access Journals (Sweden)

    Hiroshi Tanaka

    2015-11-01

    Full Text Available Augmentation of solar radiation absorbed on a flat plate solar thermal collector by a flat plate bottom reflector was numerically determined when there was a gap between the collector and reflector. The inclination of both the collector and reflector was assumed to be adjustable according to the season. A mirror-symmetric plane of the collector to the reflector was introduced, and a graphical model was proposed to calculate the amount of solar radiation reflected by the reflector and then absorbed on the collector. The performance was analyzed for three typical days at a latitude of 30°N. Solar radiation absorbed on the collector can be increased by the bottom reflector even if there is a gap between the collector and reflector. The optimum inclinations of both the collector and reflector are almost the same while the gap length is less than the lengths of the collector and reflector. However, the range of inclination of the reflector that can increase the solar radiation absorbed on the collector decreases with an increase in gap length, and the solar radiation absorbed on the collector rapidly decreased with an increase in the gap length when the reflector and/or collector were not set at a proper angle.

  14. Deployable Entry-system Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Deployable Entry-system ProjecT (ADEPT) will develop requirements for the ADEPT flight test.  Prior entry systems used high mass thermal protection...

  15. Single and dual-Gregorian reflector antenna shaped beam far-field synthesis

    Science.gov (United States)

    Mehler, M. J.

    The direct far-field G.O. synthesis of shaped beam reflector antennas has recently been treated by Mehler, Tun and Adatia (1986). These authors use a synthesis technique which exploits complex coordinates and which is based on a method originally considered by Norris and Westcott (1976). They describe the synthesis of single reflector antennas which radiate both elliptical beams and European coverage patterns. Here this technique is extended to consider a class of dual reflector antennas which possess shaped main reflectors and conic subreflectors. An example is given of a Gregorian duel reflector antenna which radiates a cross-polar field significantly smaller than that radiated by single shaped reflector antennas. In addition, the behavior of the radiation pattern as a function of the reflector diameter is investigated.

  16. A proposal to use mercury as a reflector material for decoupled moderator system

    Energy Technology Data Exchange (ETDEWEB)

    Teshigawara, Makoto; Harada, Masahide; Watanabe, Noboru; Kai, Tetsuya; Sakata, Hideaki; Ikeda, Yujiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-03-01

    It is important for a decoupled moderator system to obtain neutron pulses of a higher intensity with a narrower pulse width and a faster decay. To satisfy these requirements we propose to use mercury as a reflector material and report the neutronic performance of a mercury reflector system. The peak intensity is almost comparable to or even higher than that of the optimized lead reflector system and higher than the optimized Be reflector one. Furthermore the pulse shape is almost the same as that of optimized Be reflector system with a decoupling energy of several tens eV. A mercury reflector system does not require decouplers with a higher decoupling energy, liners nor cooling water, since mercury has a reasonably high neutron absorption cross section and could be used also as a coolant. Thus, the idea of the mercury reflector could bring about a higher neutronic performance with some engineering merits for a decoupled moderator system. (author)

  17. Deployment-related Respiratory Issues.

    Science.gov (United States)

    Morris, Michael J; Rawlins, Frederic A; Forbes, Damon A; Skabelund, Andrew J; Lucero, Pedro F

    2016-01-01

    Military deployment to Southwest Asia since 2003 in support of Operations Enduring Freedom/Iraqi Freedom/New Dawn has presented unique challenges from a pulmonary perspective. Various airborne hazards in the deployed environment include suspended geologic dusts, burn pit smoke, vehicle exhaust emissions, industrial air pollution, and isolated exposure incidents. These exposures may give rise to both acute respiratory symptoms and in some instances development of chronic lung disease. While increased respiratory symptoms during deployment are well documented, there is limited data on whether inhalation of airborne particulate matter is causally related to an increase in either common or unique pulmonary diseases. While disease processes such as acute eosinophilic pneumonia and exacerbation of preexisting asthma have been adequately documented, there is significant controversy surrounding the potential effects of deployment exposures and development of rare pulmonary disorders such as constrictive bronchiolitis. The role of smoking and related disorders has yet to be defined. This article presents the current evidence for deployment-related respiratory symptoms and ongoing Department of Defense studies. Further, it also provides general recommendations for evaluating pulmonary health in the deployed military population.

  18. Gratings and Random Reflectors for Near-Infrared PIN Diodes

    Science.gov (United States)

    Gunapala, Sarath; Bandara, Sumith; Liu, John; Ting, David

    2007-01-01

    Crossed diffraction gratings and random reflectors have been proposed as means to increase the quantum efficiencies of InGaAs/InP positive/intrinsic/ negative (PIN) diodes designed to operate as near-infrared photodetectors. The proposal is meant especially to apply to focal-plane imaging arrays of such photodetectors to be used for near-infrared imaging. A further increase in quantum efficiency near the short-wavelength limit of the near-infrared spectrum of such a photodetector array could be effected by removing the InP substrate of the array. The use of crossed diffraction gratings and random reflectors as optical devices for increasing the quantum efficiencies of quantum-well infrared photodetectors (QWIPs) was discussed in several prior NASA Tech Briefs articles. While the optical effects of crossed gratings and random reflectors as applied to PIN photodiodes would be similar to those of crossed gratings and random reflectors as applied to QWIPs, the physical mechanisms by which these optical effects would enhance efficiency differ between the PIN-photodiode and QWIP cases: In a QWIP, the multiple-quantum-well layers are typically oriented parallel to the focal plane and therefore perpendicular or nearly perpendicular to the direction of incidence of infrared light. By virtue of the applicable quantum selection rules, light polarized parallel to the focal plane (as normally incident light is) cannot excite charge carriers and, hence, cannot be detected. A pair of crossed gratings or a random reflector scatters normally or nearly normally incident light so that a significant portion of it attains a component of polarization normal to the focal plane and, hence, can excite charge carriers. A pair of crossed gratings or a random reflector on a PIN photodiode would also scatter light into directions away from the perpendicular to the focal plane. However, in this case, the reason for redirecting light away from the perpendicular is to increase the length of the

  19. The transient scattering mechanism of dipole array with reflector

    Institute of Scientific and Technical Information of China (English)

    Zhang Xue-Qin; Wang Jun-Hong; Li Zeng-Rui

    2008-01-01

    The transient backscattering mechanisms of a dipole array with reflector have been investigated from different aspects:time-domain,frequency-domain,and combined time-frequency domain,using 4×8 dipole arrays with reflector as an example.The data of scattering from the arrays under the incidence of Gaussian pulses are obtained by finite differential time domain method.The influences of the array structural parameters,incident wave parameters,and incident angles on the waveforms,spectrum,and time-frequency representations of the backseattered fields of the arrays are analysed and conclusions are drawn.From these characteristics and conclusions,it is possible to deduce the array structure inversely from the backscattered field.

  20. RATAN-600 - The world's biggest reflector at the 'cross roads'

    Science.gov (United States)

    Parijskij, Yurij N.

    1993-08-01

    The RATAN-600 new-technology telescope (NTT), which supplies about one-quarter of the observational material in Russia in the field of radio astronomy and more than 80 percent in the central, centimeter-decimeter range, is described. The RATAN-600 is the first multielement reflector radio telescope without any structure linking the surface elements. The functions normally performed by such structure are executed by the earth's surface. It is also the first radio telescope with a controlled-shape surface. In observations at different elevations about the horizon, the shape of its surface varies, remaining in the family of second-order surfaces. The RATAN-600 is also the first aperture-synthesis reflector-type telescope. The location of the radio telescope, its design, its modes of operation, and its future prospects are discussed.

  1. Conceptual Design of the Aluminum Reflector Antenna for DATE5

    Science.gov (United States)

    Qian, Yuan; Kan, Frank W.; Sarawit, Andrew T.; Lou, Zheng; Cheng, Jing-Quan; Wang, Hai-Ren; Zuo, Ying-Xi; Yang, Ji

    2016-08-01

    DATE5, a 5 m telescope for terahertz exploration, was proposed for acquiring observations at Dome A, Antarctica. In order to observe the terahertz spectrum, it is necessary to maintain high surface accuracy in the the antenna when it is exposed to Antarctic weather conditions. Structural analysis shows that both machined aluminum and carbon fiber reinforced plastic (CFRP) panels can meet surface accuracy requirements. In this paper, one design concept based on aluminum panels is introduced. This includes panel layout, details on panel support, design of a CFRP backup structure, and detailed finite element analysis. Modal, gravity and thermal analysis are all performed and surface deformations of the main reflector are evaluated for all load cases. At the end of the paper, the manufacture of a prototype panel is also described. Based on these results, we found that using smaller aluminum reflector panels has the potential to meet the surface requirements in the harsh Dome A environment.

  2. Prestack exploding reflector modeling and migration in TI media

    KAUST Repository

    Wang, H.

    2014-01-01

    Prestack depth migration in anisotropic media, especially those that exhibit tilt, can be costly using reverse time migration (RTM). We present two-way spectral extrapolation of prestack exploding reflector modeling and migration (PERM) in acoustic transversely isotropic (TI) media. We construct systematic ways to evaluate phase angles and phase velocities in dip oriented TI (DTI), vertical TI (VTI) and tilted TI (TTI) media. Migration results from the Marmousi VTI model and the BP2007 TTI model show the feasibility of our approach.

  3. Parabolic dish reflectors for solar applications approximated by simple surfaces

    OpenAIRE

    Broman, Lars; Broman, Arne

    1996-01-01

    Two different concentrating mirrors have been constructed that resemble parabolic dish reflectors. Both mirrors are made of slightly curved strips of flat, bendable material. The strips of the most simplified mirror have only large-radius circles and straight lines as boundaries. The necessary equations for making the mirrors have been derived. Also a simple way to make a stiff, lightweight frame and support for the mirror strips has been developed. Models of the mirrors have been built and s...

  4. Grating-assisted silicon-on-insulator racetrack resonator reflector.

    Science.gov (United States)

    Boeck, Robert; Caverley, Michael; Chrostowski, Lukas; Jaeger, Nicolas A F

    2015-10-05

    We experimentally demonstrate a grating-assisted silicon-on-insulator (SOI) racetrack resonator reflector with a reflect port suppression of 10.3 dB and no free spectral range. We use contra-directional grating couplers within the coupling regions of the racetrack resonator to enable suppression of all but one of the peaks within the reflect port spectrum as well as all but one of the notches within the through port spectrum.

  5. Design and testing for novel joint for wave reflectors

    Energy Technology Data Exchange (ETDEWEB)

    Tedd, J. [SPOK ApS, Copenhagen (Denmark); Friis-Madsen, E. [Loewenmark, Copenhagen (Denmark); Frigaard, P. [Aalborg Univ., Aalborg (Denmark)

    2005-07-01

    Construction of a novel joint between the main platform and the wave reflectors of the Wave Dragon has begun. This paper describes the design and testing process behind this. Tests conducted in the facilities at Aalborg University highlighted large motions, and similar force magnitudes to the previous design. This testing has influenced the design and allowed construction to begin on refitting the joint to the 1:4.5 scale prototype Wave Dragon. (au)

  6. Theoretical analysis of a parabolic torus reflector antenna with multibeam

    Institute of Scientific and Technical Information of China (English)

    杜彪; 杨可忠; 钟顺时

    1995-01-01

    The parametric equations and the formulas of unit normal vector and surface element for aparabolic torus reflector antenna are derived and the mechanism of producing multibeam is proposed, Based on physical optics, the radiation pattern formulas for the antenna are given, with which the effects of geometric parameters on the antenna are studied. The good agreement between the calculated patterns and the measured ones shows that the theory is helpful for designing parabolic torus antennas.

  7. SU-E-J-215: Towards MR-Only Image Guided Identification of Calcifications and Brachytherapy Seeds: Application to Prostate and Breast LDR Implant Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Elzibak, A; Fatemi-Ardekani, A; Soliman, A; Mashouf, S; Safigholi, H; Ravi, A; Morton, G; Song, WY [Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario (Canada); Han, D [Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario (Canada); University of California, San Diego, La Jolla, CA (United States)

    2015-06-15

    Purpose: To identify and analyze the appearance of calcifications and brachytherapy seeds on magnitude and phase MRI images and to investigate whether they can be distinguished from each other on corrected phase images for application to prostate and breast low dose rate (LDR) implant dosimetry. Methods: An agar-based gel phantom containing two LDR brachytherapy seeds (Advantage Pd-103, IsoAid, 0.8mm diameter, 4.5mm length) and two spherical calcifications (large: 7mm diameter and small: 4mm diameter) was constructed and imaged on a 3T Philips MR scanner using a 16-channel head coil and a susceptibility weighted imaging (SWI) sequence (2mm slices, 320mm FOV, TR/ TE= 26.5/5.3ms, 15 degree flip angle). The phase images were unwrapped and corrected using a 32×32, 2D Hanning high pass filter to remove background phase noise. Appearance of the seeds and calcifications was assessed visually and quantitatively using Osirix (http://www.osirix-viewer.com/). Results: As expected, calcifications and brachytherapy seeds appeared dark (hypointense) relative to the surrounding gel on the magnitude MRI images. The diameter of each seed without the surrounding artifact was measured to be 0.1 cm on the magnitude image, while diameters of 0.79 and 0.37 cm were measured for the larger and smaller calcifications, respectively. On the corrected phase images, the brachytherapy seeds and the calcifications appeared bright (hyperintense). The diameter of the seeds was larger on the phase images (0.17 cm) likely due to the dipole effect. Conclusion: MRI has the best soft tissue contrast for accurate organ delineation leading to most accurate implant dosimetry. This work demonstrated that phase images can potentially be useful in identifying brachytherapy seeds and calcifications in the prostate and breast due to their bright appearance, which helps in their visualization and quantification for accurate dosimetry using MR-only. Future work includes optimizing phase filters to best identify

  8. Terrace retro-reflector array for poloidal polarimeter on ITER.

    Science.gov (United States)

    Imazawa, R; Kawano, Y; Ono, T; Kusama, Y

    2011-02-01

    A new concept of a terrace retro-reflector array (TERRA) as part of the poloidal polarimeter for ITER is proposed in this paper. TERRA reflects a laser light even from a high incident angle in the direction of the incident-light path, while a conventional retro-reflector array cannot. Besides, TERRA can be installed in a smaller space than a corner-cube retro-reflector. In an optical sense, TERRA is equivalent to a Littrow grating, the blaze angle of which varies, depending on the incident angle. The reflected light generates a bright and dark fringe, and the bright fringe is required to travel along the incident-light path to achieve the objects of laser-aided diagnostics. In order to investigate the propagation properties of laser light reflected by TERRA, we have developed a new diffraction formula. Conditions for the propagation of the bright fringe in the direction of the incident light have been obtained using the Littrow grating model and have been confirmed in a simulation applying the new diffraction formula. Finally, we have designed laser transmission optics using TERRA for the ITER poloidal polarimeter and have calculated the light propagation of the system. The optical design obtains a high transmission efficiency, with 88.6% of the incident power returned. These results demonstrate the feasibility of applying TERRA to the ITER poloidal polarimeter.

  9. A SAW resonator with two-dimensional reflectors.

    Science.gov (United States)

    Solal, Marc; Gratier, Julien; Kook, Taeho

    2010-01-01

    It is known that a part of the loss of leaky SAW resonators is due to radiation of acoustic energy in the bus-bars. Many researchers are working on so-called phononic crystals. A 2-D grating of very strong reflectors allows these devices to fully reflect, for a given frequency band, any incoming wave. A new device based on the superposition of a regular SAW resonator and a 2-D periodic grating of reflectors is proposed. Several arrangements and geometries of the reflectors were studied and compared experimentally on 48 degrees rotated Y-cut lithium tantalate. In particular, a very narrow aperture (7.5 lambda) resonator was manufactured in the 900 MHz range. Because of its small size, this resonator has a resonance Q of only 575 when using the standard technology, whereas a resonance Q of 1100 was obtained for the new device without degradation of the other characteristics. Because of the narrow aperture, the admittance of the standard resonator showed a very strong parasitic above the resonance frequency, whereas this effect is drastically reduced for the new device. These results demonstrate the feasibility of the new approach.

  10. Reflector cells in the skin of Octopus dofleini.

    Science.gov (United States)

    Brocco, S L; Cloney, R A

    1980-01-01

    The cells that form the reflecting layer beneath the chromatophore organs of the octopus are conspicuous elements of its dermal chromatic system. Each flattened, ellipsoidal reflector cell in this layer bears thousands of peripherally radiating, discoidal, reflecting lamellae. Each lamella consists of a proteinaceous reflecting platelet enveloped by the plasmalemma. The lamellae average 90 nm in thickness and have variable diameters with a maximum of about 1.7 micrometer. Sets of reflecting lamellae are organized into functional units called reflectosomes. The lamellae in each reflectosome form a parallel array - similar to a stack of coins. The average number of lamellae in a reflectosome is 11. Adjacent lamellae are uniformly separated by an extracellular gap of about 60 nm in embedded specimens. The reflectosomes are randomly disposed over the surface of the reflector cell. The observed organization of the reflectosomes is compatible with its role as a quarter-wave thin-film interference device. The alternating reflecting lamellae and intelamellar spaces constitute layers of high and low refractive indices. Using measurements of the thicknesses and refractive indices of the platelets and interlamellar spaces, we have calculated that the color of reflected light should be blue - green, as seen in vivo. The sequence of events leading to the definitive arrangement of the reflectosomes is uncertain. The reflector cells of O. dofleini are compared and contrasted with the iridophores of squid.

  11. Shape control of distributed parameter reflectors using sliding mode control

    Science.gov (United States)

    Andoh, Fukashi; Washington, Gregory N.; Utkin, Vadim

    2001-08-01

    Sliding mode control has become one of the most powerful control methods for variable structure systems, a set of continuous systems with an appropriate switching logic. Its robustness properties and order reduction capability have made sliding mode control one of the most efficient tools for relatively higher order nonlinear plants operating under uncertain conditions. Piezo-electric materials possess the property of creating a charge when subjected to a mechanical strain, and of generating a strain when subjected to an electric field. Piezo-electric actuators are known to have a hysteresis due to the thermal motion and Coulomb interaction of Weiss domains. Because of the thermal effect the hysteresis of piezo-electric actuators is reproducible only with some uncertainty in experiments. The robustness of sliding mode control under uncertain conditions has an advantage in handling the hysteresis of piezo-electric actuators. In this research sliding mode control is used to control the shape of one- and two-dimensionally curved adaptive reflectors with piezo-electric actuators. Four discrete linear actuators for the one-dimensionally curved reflector and eight actuators for the two-dimensionally curved reflector are assumed.

  12. Design of Ring-Focus Elliptical Beam Reflector Antenna

    Directory of Open Access Journals (Sweden)

    Jun-Mo Wu

    2016-01-01

    Full Text Available A new method for the design of elliptical beam reflector antenna is presented in this paper. By means of the basic principles of ring-focus antenna, a circularly symmetric feed and two specially shaped reflectors are used to form an elliptical beam antenna. Firstly, the design process of this ring-focus elliptical beam antenna is studied in detail. Transition function is defined and used in the design process. Then, combining the needs of practical engineering, a ring-focus elliptical beam reflector antenna is manufactured and tested. The gain at center frequency (12 GHz is 37.7 dBi with an aperture efficiency of 74.6%. 3 dB beam-width in φ=0° and φ=90° plane is 2.6° and 1.4°, respectively. Ratio of the elliptical beam (ratio of 3 dB beam-width in φ=0° and φ=90° plane is 2.6/1.4=1.85, substantially equal to designed ratio 2. Simulating and testing results match well, which testify the effectiveness of this design method.

  13. Design and Thermal Analysis for Space Deployable Antenna

    Science.gov (United States)

    Guan, Fu-Ling; Huang, Jiang; Zhang, Shu-Jie

    2002-01-01

    sensibility and thermal stability. But deployable antenna always enters into and leaves the earth shadow periodically when it orbits the earth, and it is affected by the shadows of itself Thus a key design for the antenna structure is to control its deformation in a limited range. Obviously, thermal analysis is very important for such structure to maintain its high thermal stability. of a supported backbone (deployable truss) and a reflector surface (flexible mesh). All analysis in this dissertation is based on this model, such as temperature field analysis, thermal deformation analysis, thermal stress analysis, thermal vibration analysis, and so on. tetrahedral element, is discussed. And the mechanism of spider nodes, middle nodes and torsion springs in these nodes are also illustrated. 6-node triangular membrane element are deduced. A temperature analysis procedure has been programmed. The obvious change in temperature happens when the antenna enter into the earth shadow, so this case should be studied to decide whether the temperature of the structure and its components are in the limited range or not. membrane element are put forward. According to the stiffness matrix of these elements and the structural equilibrium equations, thermal deformation and thermal stress of the structure can be computed. The results show that either the thermal deformation or the thermal stress is in the desired range, they have little effect on the shape and stiffness of the entire structure. vibration. The thermally vibration responses of the antenna are studied when it enters into the earth shadow from sunshine and when it enters into sunshine from the earth shadow. The results show that in both cases, there is no vibration in Y direction. The velocity and acceleration in X direction and Z direction are both small, but the displacement in X direction is large, the maximum is 6.5mm. Keyword: Deployable antenna; self-shadow; thermal deformation; thermal stress

  14. Successful Starshade Petal Deployment Tolerance Verification in Support of NASA's Technology Development for Exoplanet Missions

    Science.gov (United States)

    Webb, D.; Kasdin, N. J.; Lisman, D.; Shaklan, S.; Thomson, M.; Cady, E.; Marks, G. W.; Lo, A.

    2014-01-01

    A Starshade is a sunflower-shaped satellite with a large inner disk structure surrounded by petals that flies in formation with a space-borne telescope, creating a deep shadow around the telescope over a broad spectral band to permit nearby exoplanets to be viewed. Removing extraneous starlight before it enters the observatory optics greatly loosens the tolerances on the telescope and instrument that comprise the optical system, but the nature of the Starshade dictates a large deployable structure capable of deploying to a very precise shape. These shape requirements break down into key mechanical requirements, which include the rigid-body position and orientation of each of the petals that ring the periphery of the Starshade. To verify our capability to meet these requirements, we modified an existing flight-like Astromesh reflector, provided by Northrup Grumman, as the base ring to which the petals attach. The integrated system, including 4 of the 30 flight-like subscale petals, truss, connecting spokes and central hub, was deployed tens of times in a flight-like manner using a gravity compensation system. After each deployment, discrete points in prescribed locations covering the petals and truss were measured using a highly-accurate laser tracker system. These measurements were then compared against the mechanical requirements, and the as-measured data shows deployment accuracy well within our milestone requirements and resulting in a contrast ratio consistent with exoplanet detection and characterization.

  15. The Position and Attitude of Sub-reflector Modeling for TM65 m Radio Telescope

    Science.gov (United States)

    Sun, Z. X.; Chen, L.; Wang, J. Q.

    2016-01-01

    In the course of astronomical observations, with changes in angle of pitch, the large radio telescope will have different degrees of deformation in the sub-reflector support, back frame, main reflector etc, which will lead to the dramatic decline of antenna efficiency in both high and low elevation. A sub-reflector system of the Tian Ma 65 m radio telescope has been installed in order to compensate for the gravitational deformations of the sub-reflector support and the main reflector. The position and attitude of the sub-reflector are variable in order to improve the pointing performance and the efficiency at different elevations. In this paper, it is studied that the changes of position and attitude of the sub-reflector have influence on the efficiency of antenna in the X band and Ku band. A model has been constructed to determine the position and attitude of the sub-reflector with elevation, as well as the point compensation model, by observing the radio source. In addition, antenna efficiency was tested with sub-reflector position adjusted and fixed. The results show that the model of sub-reflector can effectively improve the efficiency of the 65 m radio telescope. In X band, the aperture efficiency of the radio telescope reaches more than 60% over the entire elevation range.

  16. Newberry Seismic Deployment Fieldwork Report

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J; Templeton, D C

    2012-03-21

    This report summarizes the seismic deployment of Lawrence Livermore National Laboratory (LLNL) Geotech GS-13 short-period seismometers at the Newberry Enhanced Geothermal System (EGS) Demonstration site located in Central Oregon. This Department of Energy (DOE) demonstration project is managed by AltaRock Energy Inc. AltaRock Energy had previously deployed Geospace GS-11D geophones at the Newberry EGS Demonstration site, however the quality of the seismic data was somewhat low. The purpose of the LLNL deployment was to install more sensitive sensors which would record higher quality seismic data for use in future seismic studies, such as ambient noise correlation, matched field processing earthquake detection studies, and general EGS microearthquake studies. For the LLNL deployment, seven three-component seismic stations were installed around the proposed AltaRock Energy stimulation well. The LLNL seismic sensors were connected to AltaRock Energy Gueralp CMG-DM24 digitizers, which are powered by AltaRock Energy solar panels and batteries. The deployment took four days in two phases. In phase I, the sites were identified, a cavity approximately 3 feet deep was dug and a flat concrete pad oriented to true North was made for each site. In phase II, we installed three single component GS-13 seismometers at each site, quality controlled the data to ensure that each station was recording data properly, and filled in each cavity with native soil.

  17. OMV multiple deployments of lightsats

    Science.gov (United States)

    Smith, William L.; Walker, James D.

    1988-06-01

    The design and capabilities of the NASA Orbital Maneuvering Vehicle (OMV) are reviewed, and the potential value of the Shuttle-borne OMV for deploying lightweight satellites (lightsats) into different orbits is discussed and illustrated with extensive drawings and diagrams. Assuming 100-lb lightsats in extended GAS canisters, the OMV could separate from the Orbiter at 16 nmi and deploy six lightsats each at altitudes 430, 700, and 970 nmi before rejoining the Orbiter at 160 nmi. Also considered are configurations with 8 or 12 200-lb lightsats and the fittings for Titan-4 launch of OMV/lightsat packages.

  18. IPv6 deployment and management

    CERN Document Server

    Dooley, Michael

    2013-01-01

    A guide for understanding, deploying, and managing Internet Protocol version 6 The growth of the Internet has created a need for more addresses than are available with Internet Protocol version 4 (IPv4)-the protocol currently used to direct almost all Internet traffic. Internet Protocol version 6 (IPv6)-the new IP version intended to ultimately succeed IPv4-will expand the addressing capacity of the Internet to support the explosive growth of users and devices on the Internet as well as add flexibility to allocating addresses and efficiency for routing traffic. IPv6 Deploy

  19. Department of Defense, Deployment Health Clinical Center

    Science.gov (United States)

    ... related to deployment health assessments, combat and operational stress programs, deployment-limiting health conditions and deployment-related exposures. Learn More In the News Experts Explore How Combat Roles May Affect Women’s Psychological Health Deployments can be 'significant stressor' ...

  20. Feasibility of applying the new improved PCR/LDR/capillary electrophoresis on prenatal diagnosis of fetal beta thalassaemia%新改良PCR/LDR/毛细管电泳技术产前诊断胎儿β-地中海贫血的可行性研究

    Institute of Scientific and Technical Information of China (English)

    廖茜; 易萍; 郑英如; 俞丽丽; 钟小林; 黄寅虎; 韩磊; 朱玉娟; 李力

    2014-01-01

    目的 研究采用新改良聚合酶链反应(PCR)/连接酶检测反应(LDR)/毛细管电泳技术产前诊断胎儿β-地中海贫血的可行性.方法 使用不同浓度梯度的正常DNA与微量β-地中海贫血突变杂合子DNA混合后进行PCR扩增,扩增产物进行LDR反应后通过毛细管电泳技术检测其连接产物.采用CEC8000型遗传分析仪分析LDR产物,并观察其灵敏度.结果 将含有相同浓度CD17(A→T)突变的扩增产物作为LDR模板,采用8U DNA连接酶进行连接反应,检测灵敏度可达1∶5000,产物峰的面积随着正常人外周血DNA浓度的增加而减少,至1∶10000处不能与杂峰区分,且无CD 17(A→T)突变扩增产物的阴性对照未检测到LDR产物.正常孕妇血浆DNA中加入20pg CD17(A→T)突变杂合子外周血DNA扩增产物,LDR产物峰可明显与杂峰区分.结论 新改良PCR/LDR/毛细管电泳技术有望通过孕妇血浆DNA检测进行β-地中海贫血的产前诊断.

  1. ANALISIS PERBANDINGAN OUTPUT DAYA LISTRIK PANEL SURYA SISTEM TRACKING DENGAN SOLAR REFLECTOR

    Directory of Open Access Journals (Sweden)

    I B Kd Surya Negara

    2016-03-01

    Full Text Available Indonesia merupakan negara beriklim tropis yang memiliki intensitas radiasi matahari yang sangat besar dan intensitas radiasi tersebut berpotensi untuk dikembangkan menjadi Pembangkit Listrik Tenaga Surya. Efisiensi dari panel surya saat ini masih perlu pertimbangan lebih lanjut. Efisiensi panel surya yang rendah ini, berpengaruh pada hasil output daya listrik yang dihasilkan. Upaya untuk meningkatkan output daya listrik panel surya, yaitu dengan sistem tracking dan solar reflector. Penelitian ini bertujuan untuk mengetahui output daya listrik yang lebih maksimal. Metode dalam penelitian ini menggunakan sistem tracking yang pergerakannya berdasarkan waktu dan menggunakan solar reflector dengan cermin datar dan sudut reflector yang berbeda. Hasil dari perbandingan sistem tracking dengan solar reflector yaitu solar reflector menghasilkan output daya listrik lebih besar dibandingan dengan sistem tracking, dimana solar reflector menghasilkan output daya listrik sebesar 0.1224 Watt dan sistem tracking sebesar 0.1136 Watt.

  2. Demonstration of a single-crystal reflector-filter for enhancing slow neutron beams

    DEFF Research Database (Denmark)

    Muhrer, G.; Schonfeldt, T.; Iverson, E. B.

    2016-01-01

    The cold polycrystalline beryllium reflector-filter concept has been used to enhance the cold neutron emission of cryogenic hydrogen moderators, while suppressing the intermediate wavelength and fast neutron emission at the same time. While suppressing the fast neutron emission is often desired......, the suppression of intermediate wavelength neutrons is often unwelcome. It has been hypothesized that replacing the polycrystalline reflector-filter concept with a single-crystal reflector-filter concept would overcome the suppression of intermediate wavelength neutrons and thereby extend the usability...... of the reflector-filter concept to shorter but still important wavelengths. In this paper we present the first experimental data on a single-crystal reflector-filter at a reflected neutron source and compare experimental results with hypothesized performance. We find that a single-crystal reflector-filter retains...

  3. Study of a flowerlike deployable structure:

    OpenAIRE

    Luo, Ani; Liu, Heping; Li, Cheng; Wang, Yongfan

    2013-01-01

    A deployable structure is a kind of mechanism that can be folded and deployed automatically. It is able to form required shape or curved surface after deployment. In this paper, a flowerlike deployable structure, which forms a circle plane after deployment, was studied. First, the required circle plane was decomposed to determine the shapes of the members. Then the relation expressions were set up, which include the structural dimensions of the members and how to calculate the volume of the m...

  4. Impact of beryllium reflector ageing on Safari–1 reactor core parameters / L.E. Moloko

    OpenAIRE

    Moloko, Lesego Ernest

    2011-01-01

    The build–up of 6Li and 3He, that is, the strong thermal neutron absorbers or the so called "neutron poisons", in the beryllium reflector changes the physical characteristics of the reactor, such as reactivity, neutron spectra, neutron flux level, power distribution, etc.; furthermore,gaseous isotopes such as 3H and 4He induce swelling and embrittlement of the reflector. The SAFARI–1 research reactor, operated by Necsa at Pelindaba in South Africa, uses a beryllium reflector on...

  5. Neutronic optimization of premoderator and reflector for decoupled hydrogen moderator in 1 MW spallation neutron source

    CERN Document Server

    Harada, M; Kai, T; Sakata, H; Watanabe, N; Ikeda, Y

    2002-01-01

    For a decoupled liquid-hydrogen moderator, optimization studies have been performance on a premoderator and reflector materials (Pb, Be, Fe and Hg) together with several decoupling energies to realize a higher neutronic performance. The result indicated that, among four reflector materials mentioned above, the best neutronic performance could be obtained by adopting a Pb reflector with an optimized premoderator and an appropriate decoupling energy. (author)

  6. Space deployable truss structure design

    Science.gov (United States)

    Coyner, J. V., Jr.; Tobey, W. H.

    1981-01-01

    The development status of the deployable box truss structure is summarized. Potential applications for this structural system are described. Structural and component design requirements derived from these applications are discussed. Components of prototype 4.6 m cubes which incorporate graphite/epoxy structural members, fittings, and mechanisms are described. The benefits of the component designs and their respective manufacturing processes are presented.

  7. A Rapidly Deployable Bridge System

    Science.gov (United States)

    2013-01-15

    A Rapidly Deployable Bridge System Gareth R. Thomas1 and Bernard J. Sia2 1ATA Engineering, 11995 El Camino Real, San Diego, CA 92130; PH (858) 480...PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) ATA Engineering,11995 El Camino Real,San Diego,CA,92130 8. PERFORMING ORGANIZATION REPORT NUMBER

  8. OMV Deployed From Space Station

    Science.gov (United States)

    1986-01-01

    In this 1986 artist's concept, the Orbital Maneuvering Vehicle (OMV), at right, prepares to reboost the Hubble Space Telescope after being deployed from an early Space Station configuration (left). As envisioned by Marshall Space Flight Center plarners, the OMV would be a remotely-controlled free-flying space tug which would place, rendezvous, dock, and retrieve orbital payloads.

  9. A rapid detection method of inbred mouse DNA genetic quality based on PCR-LDR platform%基于PCR-LDR平台的近交系小鼠遗传质量快速检测方法

    Institute of Scientific and Technical Information of China (English)

    谢雯; 鲍世民; 谢建云; 李凯; 周宇荀; 肖君华

    2012-01-01

    目的 建立基于PCR-LDR平台的近交系小鼠SNP快速分型方法,用于检测实验小鼠的遗传质量与品系纯度.方法 利用可移植性极高的PCR-LDR技术,以常见近交系小鼠为研究对象,选取了21条染色体上的45个SNP位点,分别设计引物和探针,经过筛选和验证,建立了多重PCR-LDR(polymerase chain reaction and ligase detection reaction,PCR-LDR)分型方案.结果 四组多重PCR-LDR可实现45个SNP位点的基因分型,其中43个、44个与45个SNP在样本中的检出率分别为100%、90.9%与36.4%.所有样本经分型确定为纯合体,并得到了常见近交系小鼠SNP位点信息.结论 实现了常见近交系小鼠快速、高通量的基因分型,可用于遗传质量检测和品系鉴定.%Objrctlve Purity of laboratory animals plays a critical role affecting the experimental results. The aim of this study was to validate a high-throughput genotyping platform, valuable in inbred mouse genetic DNA monitoring and strain identification. Methods Multiple polymerase chain reaction and ligase detection reaction (PCR-LDR) genotyping panels were constructed. Forty-five single-nucleotide polymorphism (SNP) on 21 chromosomes were selected as targets, as well as specific primers and probes to these SNP were designed, respectively. A multiple PCR-LDR genotyping protocol was established. Results Forty-five SNP were successfully genotyped in four panels. The positive detection rate of 43, 44 and 45 SNPs were 100% , 90. 9% and 36. 4% , respectively. All samples collected were homozygous and their genotypes were identified by PCR-LDR. Conclusion The result9 of this study provide a rapid and high-throughput genotyping approach, which is sufficient for genetic contamination monitoring and strain identification.

  10. Prediction of scattering cross-section reductions due to plate orthogonality errors in trihedral radar reflectors

    Science.gov (United States)

    Keen, K. M.

    1983-02-01

    A method is developed for the determination of the reduction in scattering cross-section levels due to nonorthogonal alignment of the plates in trihedral radar corner reflectors. This method is based on the technique for finding the effective error at any direction of incidence. The method can be applied to any regular reflector shape and is accurate for any incident ray direction in the reflector main beam zone. It is determined that this method gives good agreement with experimental results for a wide range of reflector sizes, although the analysis is not exact.

  11. Analysis and Design of a New Shaped Spherical Reflector Antenna with a Horn Feed

    Institute of Scientific and Technical Information of China (English)

    LIN Yan; HUANG Bin; ZHU Quan-fu; YUAN Yuan

    2009-01-01

    A design method of a new shaped spherical reflector antenna with a horn feed for wide-angle scanning is presented, in which the horn's phase center need not be found out and its optimal position can be determined. It is found from numerical calculation that the shaped spherical reflector antenna has better electrical performance than that of the spherical reflector antenna, at the maximum gain value under the conditions of the same feed and reflector aperture, and can be used as a wide angle searching antenna.

  12. Characterization of a Bifacial Photovoltaic Panel Integrated with External Diffuse and Semimirror Type Reflectors

    Directory of Open Access Journals (Sweden)

    P. Ooshaksaraei

    2013-01-01

    Full Text Available Silicon wafer accounts for almost one-half the cost of a photovoltaic (PV panel. A bifacial silicon solar cell is attractive due to its potential of enhancing power generation from the same silicon wafer in comparison with a conventional monofacial solar cell. The bifacial PV cell is able to capture solar radiation by back surface. This ability requires a suitable reflector appropriately oriented and separated from the cell’s rear surface. In order to optimize the bifacial solar cell performance with respect to an external back surface reflector, diffuse and semimirror reflectors were investigated at various angles and separations from the back surface. A simple bifacial solar panel, consisting of four monocrystalline Si solar cells, was designed and built. Reflection from the rear surface was provided by an extended semimirror and a white-painted diffuse reflector. Maximum power generation was observed at 30° with respect to ground for the semimirror reflector and 10° for diffuse reflector at an optimized reflector-panel separation of 115 mm. Output power enhancement of 20% and 15% from semimirror and diffuse reflectors, respectively, were observed. This loss from diffuse reflector is attributed to scattering of light beyond the rear surface capture cross-section of the bifacial solar panel.

  13. Demonstration of a single-crystal reflector-filter for enhancing slow neutron beams

    Science.gov (United States)

    Muhrer, G.; Schönfeldt, T.; Iverson, E. B.; Mocko, M.; Baxter, D. V.; Hügle, Th.; Gallmeier, F. X.; Klinkby, E. B.

    2016-09-01

    The cold polycrystalline beryllium reflector-filter concept has been used to enhance the cold neutron emission of cryogenic hydrogen moderators, while suppressing the intermediate wavelength and fast neutron emission at the same time. While suppressing the fast neutron emission is often desired, the suppression of intermediate wavelength neutrons is often unwelcome. It has been hypothesized that replacing the polycrystalline reflector-filter concept with a single-crystal reflector-filter concept would overcome the suppression of intermediate wavelength neutrons and thereby extend the usability of the reflector-filter concept to shorter but still important wavelengths. In this paper we present the first experimental data on a single-crystal reflector-filter at a reflected neutron source and compare experimental results with hypothesized performance. We find that a single-crystal reflector-filter retains the long-wavelength benefit of the polycrystalline reflector-filter, without suffering the same loss of important intermediate wavelength neutrons. This finding extends the applicability of the reflector-filter concept to intermediate wavelengths, and furthermore indicates that the reflector-filter benefits arise from its interaction with fast (background) neutrons, not with intermediate wavelength neutrons of potential interest in many types of neutron scattering.

  14. Demonstration of a single-crystal reflector-filter for enhancing slow neutron beams

    Energy Technology Data Exchange (ETDEWEB)

    Muhrer, G. [European Spallation Source, Lund (Sweden); Los Alamos Neutron Science Center, Los Alamos National Laboratory, Los Alamos, NM (United States); Schönfeldt, T. [Center for Nuclear Technologies, Technical University of Denmark, Roskilde (Denmark); European Spallation Source, Lund (Sweden); Iverson, E.B., E-mail: iversoneb@ornl.gov [Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, TN (United States); Mocko, M. [Los Alamos Neutron Science Center, Los Alamos National Laboratory, Los Alamos, NM (United States); Baxter, D.V. [Center for the Exploration of Energy and Matter, Indiana University, Bloomington, IN (United States); Hügle, Th.; Gallmeier, F.X. [Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, TN (United States); Klinkby, E.B. [Center for Nuclear Technologies, Technical University of Denmark, Roskilde (Denmark); European Spallation Source, Lund (Sweden)

    2016-09-11

    The cold polycrystalline beryllium reflector-filter concept has been used to enhance the cold neutron emission of cryogenic hydrogen moderators, while suppressing the intermediate wavelength and fast neutron emission at the same time. While suppressing the fast neutron emission is often desired, the suppression of intermediate wavelength neutrons is often unwelcome. It has been hypothesized that replacing the polycrystalline reflector-filter concept with a single-crystal reflector-filter concept would overcome the suppression of intermediate wavelength neutrons and thereby extend the usability of the reflector-filter concept to shorter but still important wavelengths. In this paper we present the first experimental data on a single-crystal reflector-filter at a reflected neutron source and compare experimental results with hypothesized performance. We find that a single-crystal reflector-filter retains the long-wavelength benefit of the polycrystalline reflector-filter, without suffering the same loss of important intermediate wavelength neutrons. This finding extends the applicability of the reflector-filter concept to intermediate wavelengths, and furthermore indicates that the reflector-filter benefits arise from its interaction with fast (background) neutrons, not with intermediate wavelength neutrons of potential interest in many types of neutron scattering.

  15. Reflector and Shield Material Properties for Project Prometheus

    Energy Technology Data Exchange (ETDEWEB)

    J. Nash

    2005-11-02

    This letter provides updated reflector and shield preliminary material property information to support reactor design efforts. The information provided herein supersedes the applicable portions of Revision 1 to the Space Power Program Preliminary Reactor Design Basis (Reference (a)). This letter partially answers the request in Reference (b) to provide unirradiated and irradiated material properties for beryllium, beryllium oxide, isotopically enriched boron carbide ({sup 11}B{sub 4}C) and lithium hydride. With the exception of {sup 11}B{sub 4}C, the information is provided in Attachments 1 and 2. At the time of issuance of this document, {sup 11}B{sub 4}C had not been studied.

  16. A Van Atta reflector consisting of half-wave dipoles

    DEFF Research Database (Denmark)

    Appel-Hansen, Jørgen

    1966-01-01

    The reradiation pattern of a passive Van Atta reflector consisting of half-wave dipoles is investigated. The character of the reradiation pattern first is deduced by qualitative and physical considerations. Various types of array elements are considered and several geometrical configurations...... of these elements are outlined. Following this, an analysis is made of the reradiation pattern of a linear Van Atta array consisting of four equispaced half-wave dipoles. The general form of the reradiation pattern is studied analytically. The influence of scattering and coupling is determined and the dependence...

  17. Q-switched distributed-Bragg-reflector ytterbium laser

    Science.gov (United States)

    Ouslimani, H.; Bastard, L.; Broquin, J.-E.

    2013-03-01

    A passively Q-switched distributed-Bragg-reflector laser made in glass integrated optics technology, and operating around 1030 nm, is designed, realized and investigated. The laser is formed by an ion-exchanged single mode waveguide realized in an Ytterbium doped phosphate glass. The Q-switching behavior is obtained by hybridizing a saturable absorber film on the waveguides. This allows the realization of a short and simple laser cavity having both pulsed and a narrow linewidth emission. Its experimental characterization leads to the observation of a stable repetition rate of 12.5 kHz and a stable pulse duration of 9.2 ns FWHM.

  18. The dihedral corner reflector as a reference target

    Science.gov (United States)

    Corona, P.; Ferrara, G.; Gennarelli, C.

    The radiation properties of a dihedral corner reflector are analyzed in detail in order to assess the effectiveness of such a device as a standard reference in experimental determinations of radar cross section. A short review of reference targets is presented, and the physical optics approach and the images method are used to develop a mathematical model for the dihedral corner. Results from a computer program implemented to evaluate the field backscattered from the corner and to compute patterns for various dihedral sizes are reported. It is concluded that the dihedral corner can be conveniently used as a reference target by scanning in a plane containing the corner wedge.

  19. Photoluminescence and X-ray Diffraction of Distributed Bragg Reflector

    Institute of Scientific and Technical Information of China (English)

    LI Lin; LI Yong-da; LIU Wen-li; LU Bin; JU Guo-xian; ZHANG Yong-ming; HAO Yong-qin; SU Wei; ZHONG Jing-chang

    2004-01-01

    Spectral and structural characteristics of distributed Bragg reflector (DBR) in vertical-cavity surface-emitting lasers were studied with photoluminescence and double- crystal X- ray diffraction measurement. The expected high quality epitaxial DBR structure was verified. In the X- ray double- crystal rocking curves of DBR the zeroth- order peak, the first and second order satellite peaks were measured.Splitting of diffraction peak appeared in the rocking curves was analyzed. The effects of introduced deep energy levels on the structural perfection and optical properties were discussed.

  20. VSHOT: a tool for characterizing large, imprecise reflectors

    Energy Technology Data Exchange (ETDEWEB)

    Jones, S.A.; Neal, D.R.; Gruetzner, J.K.; Houser, R.M.; Edgar, R.M. [Sandia National Labs., Albuquerque, NM (United States); Wendelin, T.J. [National Renewable Energy Lab., Golden, CO (United States)

    1996-11-01

    A prototype Video Scanning Hartmann Optical Tester (VSHOT) has been developed to characterize the optics of dish-type solar concentrators. VSHOT is a flexible platform that may characterize any large reflector with a focal length over diameter ratio (f{number_sign}) greater than 0. 45, and RMS optical error in the 0. I - I 0 milliradian range. The VSHOT hardware, software, and operation are described. Measurement uncertainty and preliminary test results are discussed. Another potential application being explored for the VSHOT is the quality assurance of slumped-glass automobile windshields. Preliminary test results from a reference optic and a section of a windshield are presented.

  1. A Multiplex PCR/LDR Assay for the Simultaneous Identification of Category A Infectious Pathogens: Agents of Viral Hemorrhagic Fever and Variola Virus.

    Directory of Open Access Journals (Sweden)

    Sanchita Das

    Full Text Available CDC designated category A infectious agents pose a major risk to national security and require special action for public health preparedness. They include viruses that cause viral hemorrhagic fever (VHF syndrome as well as variola virus, the agent of smallpox. VHF is characterized by hemorrhage and fever with multi-organ failure leading to high morbidity and mortality. Smallpox, a prior scourge, has been eradicated for decades, making it a particularly serious threat if released nefariously in the essentially non-immune world population. Early detection of the causative agents, and the ability to distinguish them from other pathogens, is essential to contain outbreaks, implement proper control measures, and prevent morbidity and mortality. We have developed a multiplex detection assay that uses several species-specific PCR primers to generate amplicons from multiple pathogens; these are then targeted in a ligase detection reaction (LDR. The resultant fluorescently-labeled ligation products are detected on a universal array enabling simultaneous identification of the pathogens. The assay was evaluated on 32 different isolates associated with VHF (ebolavirus, marburgvirus, Crimean Congo hemorrhagic fever virus, Lassa fever virus, Rift Valley fever virus, Dengue virus, and Yellow fever virus as well as variola virus and vaccinia virus (the agent of smallpox and its vaccine strain, respectively. The assay was able to detect all viruses tested, including 8 sequences representative of different variola virus strains from the CDC repository. It does not cross react with other emerging zoonoses such as monkeypox virus or cowpox virus, or six flaviviruses tested (St. Louis encephalitis virus, Murray Valley encephalitis virus, Powassan virus, Tick-borne encephalitis virus, West Nile virus and Japanese encephalitis virus.

  2. A Multiplex PCR/LDR Assay for the Simultaneous Identification of Category A Infectious Pathogens: Agents of Viral Hemorrhagic Fever and Variola Virus

    Science.gov (United States)

    Das, Sanchita; Rundell, Mark S.; Mirza, Aashiq H.; Pingle, Maneesh R.; Shigyo, Kristi; Garrison, Aura R.; Paragas, Jason; Smith, Scott K.; Olson, Victoria A.; Larone, Davise H.; Spitzer, Eric D.; Barany, Francis; Golightly, Linnie M.

    2015-01-01

    CDC designated category A infectious agents pose a major risk to national security and require special action for public health preparedness. They include viruses that cause viral hemorrhagic fever (VHF) syndrome as well as variola virus, the agent of smallpox. VHF is characterized by hemorrhage and fever with multi-organ failure leading to high morbidity and mortality. Smallpox, a prior scourge, has been eradicated for decades, making it a particularly serious threat if released nefariously in the essentially non-immune world population. Early detection of the causative agents, and the ability to distinguish them from other pathogens, is essential to contain outbreaks, implement proper control measures, and prevent morbidity and mortality. We have developed a multiplex detection assay that uses several species-specific PCR primers to generate amplicons from multiple pathogens; these are then targeted in a ligase detection reaction (LDR). The resultant fluorescently-labeled ligation products are detected on a universal array enabling simultaneous identification of the pathogens. The assay was evaluated on 32 different isolates associated with VHF (ebolavirus, marburgvirus, Crimean Congo hemorrhagic fever virus, Lassa fever virus, Rift Valley fever virus, Dengue virus, and Yellow fever virus) as well as variola virus and vaccinia virus (the agent of smallpox and its vaccine strain, respectively). The assay was able to detect all viruses tested, including 8 sequences representative of different variola virus strains from the CDC repository. It does not cross react with other emerging zoonoses such as monkeypox virus or cowpox virus, or six flaviviruses tested (St. Louis encephalitis virus, Murray Valley encephalitis virus, Powassan virus, Tick-borne encephalitis virus, West Nile virus and Japanese encephalitis virus). PMID:26381398

  3. Design constraints on Cherenkov telescopes with Davies-Cotton reflectors

    CERN Document Server

    Bretz, Thomas

    2013-01-01

    This paper discusses the construction of high-performance ground-based gamma-ray Cherenkov telescopes with a Davies-Cotton reflector. For the design of such telescopes, usually physics constrains the field-of-view, while the photo-sensor size is defined by limited options. Including the effect of light-concentrators in front of the photo sensor, it is demonstrated that these constraints are enough to mutually constrain all other design parameters. The dependability of the various design parameters naturally arises once a relationship between the value of the point-spread functions at the edge of the field-of-view and the pixel field-of-view is introduced. To be able to include this constraint into a system of equations, an analytical description for the point-spread function of a tessellated Davies-Cotton reflector is derived from Taylor developments and ray-tracing simulations. Including higher order terms renders the result precise on the percent level. Design curves are provided within the typical phase sp...

  4. Some Broadband Calculated RF Scatter from the Trihedral Corner Reflector

    Science.gov (United States)

    Mokole, E. L.; Gold, B. T.; Taylor, D. J.; Sarkar, T. K.; Hansen, J. P.

    To understand the target-like artifacts in radar returns called sea spikes 1 that are induced by ocean scatter,2 the WIPL-D3 and WIPL-DP4 electromagnetics codes are used to calculate monostatic and bistatic radar cross sections (RCSs) of a trihedral comer reflector at 1.5, 3.8, and 7 GHz for vertically and horizontally polarized fields. These computations are part of a larger effort to provide theoretical comparisons for recent scatter data from a 1-m trihedral reflector that was collected over 1.9 to 11.5 GHz in the open ocean with a short-pulse ultrawideband (UWB) system. Over the last eight years, this UWB experimental radar, called the microwave microscope (MWM), has been used in a series of measurements at the Atlantic Underwater Test and Experiment Center (AUTEC) in the Bahamas to investigate the low-elevation (grazing angles less than 4°)scatter of RF signals from the open ocean in an attempt to understand and mitigate the sea-spike phenomenon.

  5. Soiling and Cleaning of Polymer Film Solar Reflectors

    Directory of Open Access Journals (Sweden)

    Christopher Sansom

    2016-11-01

    Full Text Available This paper describes the accelerated ageing of commercially available silvered polymer film by contact cleaning using brushes and water in the presence of soiling created by dust and sand particles. These conditions represent cleaning regimes in real concentrating solar power (CSP solar fields in arid environments, where contact cleaning using brushes and water is often required to clean the reflecting surfaces. Whilst suitable for glass reflectors, this paper discusses the effects of these established cleaning processes on the optical and visual characteristics of polymer film surfaces, and then describes the development of a more benign but effective contact cleaning process for cleaning polymer reflectors. The effects of a range of cleaning brushes are discussed, with and without the presence of water, in the presence of sand and dust particles from selected representative locations. The experiments were repeated using different experimental equipment at Plataforma Solar de Almería (PSA in Spain and Cranfield University in the UK. The results highlight differences that are attributable to the experimental methods used. Reflectance measurements and visual inspection show that a soft cleaning brush with a small amount of water, used in a cleaning head with both linear and rotational motion, can clean polymer film reflecting surfaces without inflicting surface damage or reducing specular reflectance.

  6. Iterative alignment of reflector segments using a laser tracker

    Science.gov (United States)

    Cabrera Cuevas, Lizeth; Lucero Alvarez, Maribel; Leon-Huerta, Andrea; Hernandez Rios, Emilio; Hernandez Lázaro, Josefina; Tzile Torres, Carlos; Castro Santos, David; Gale, David M.; Wilson, Grant; Narayanan, Gopal; Smith, David R.

    2013-04-01

    The Large Millimeter Telescope (LMT) is a 50m diameter millimetre-wave radio telescope situated on the summit of Sierra Negra, Puebla, at an altitude of 4600 meters. The reflector surface of the LMT currently employs84 segments arranged in three annular rings. Each segment is comprised of 8 precision composite subpanels located on five threaded adjusters. During the current primary surface refurbishment, individual segments are aligned in the telescope basement using a laser tracker. This allows increased spatial resolution in shorter timescales, resulting in the opportunity for improved logistics and increased alignment precision. To perform segment alignment an iterative process is carried out whereby the surface is measured and subpanel deformations are corrected with the goal of 40 microns RMS. In practice we have been able to achieve RMS errors of almost 20 microns, with 35 microns typical. The number of iterations varies from around ten to over 20, depending mainly on the behaviour of the mechanical adjusters that support the individual subpanels. Cross marks scribed on the reflector surface are used as fiducials, because their positions on the paraboloid are well known. Measurement data is processed using a robust curve fitting algorithm which provides a map of the surface showing the subpanel deviations. From this map the required subpanel adjuster movements are calculated allowing surface improvement in a stepwise manner.

  7. Ultraviolet reflector materials for solar detoxification of hazardous waste

    Energy Technology Data Exchange (ETDEWEB)

    Jorgensen, G.; Govindarajan, R.

    1991-07-01

    Organic waste detoxification requires cleavage of carbon bonds. Such reactions can be photo-driven by light that is energetic enough to disrupt such bonds. Alternately, light can be used to activate catalyst materials, which in turn can break organic bonds. In either case, photons with wavelengths less than 400 nm are required. Because the terrestrial solar resource below 400 nm is so small (roughly 3% of the available spectrum), highly efficient optical concentrators are needed that can withstand outdoor service conditions. In the past, optical elements for solar application have been designed to prevent ultraviolet (uv) radiation from reaching the reflective layer to avoid the potentially harmful effects of such light on the collector materials themselves. This effectively forfeits the uv part of the spectrum in return for some measure of protection against optical degradation. To optimize the cost/performance benefit of photochemical reaction systems, optical materials must be developed that are not only highly efficient but also inherently stable against the radiation they are designed to concentrate. The requirements of uv optical elements in terms of appropriate spectral bands and level of reflectance are established based upon the needs of photochemical applications. Relevant literature on uv reflector materials is reviewed which, along with discussions with industrial contacts, allows the establishment of a data base of currently available materials. Although a number of related technologies exist that require uv reflectors, to date little attention has been paid to achieving outdoor durability required for solar applications. 49 refs., 3 figs.

  8. Lifecycle Readiness and Ship Deployment

    Science.gov (United States)

    2013-06-01

    The physical fatigue associated with ship motions has significant consequences for today’s minimally manned ships. “Because of minimally sized...a deployment. The inefficiencies in performance may develop from lack of training, different personal aptitude, and individual’s mental or physical ...exacerbation of symptoms known as the avalanche phenomenon follows which includes: increased salivation, bodily warmth , and light- headedness” (Stevens

  9. The effects of stainless steel radial reflector on core reactivity for small modular reactor

    Science.gov (United States)

    Kang, Jung Kil; Hah, Chang Joo; Cho, Sung Ju; Seong, Ki Bong

    2016-01-01

    Commercial PWR core is surrounded by a radial reflector, which consists of a baffle and water. Radial reflector is designed to reflect neutron back into the core region to improve the neutron efficiency of the reactor and to protect the reactor vessels from the embrittling effects caused by irradiation during power operation. Reflector also helps to flatten the neutron flux and power distributions in the reactor core. The conceptual nuclear design for boron-free small modular reactor (SMR) under development in Korea requires to have the cycle length of 4˜5 years, rated power of 180 MWth and enrichment less than 5 w/o. The aim of this paper is to analyze the effects of stainless steel radial reflector on the performance of the SMR using UO2 fuels. Three types of reflectors such as water, water/stainless steel 304 mixture and stainless steel 304 are selected to investigate the effect on core reactivity. Additionally, the thickness of stainless steel and double layer reflector type are also investigated. CASMO-4/SIMULATE-3 code system is used for this analysis. The results of analysis show that single layer stainless steel reflector is the most efficient reflector.

  10. Three-dimensional photonic crystal intermediate reflectors for enhanced light-trapping in tandem solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Uepping, Johannes; Bielawny, Andreas; Wehrspohn, Ralf B. [Institute of Physics, Martin-Luther-Universitaet Halle-Wittenberg, Halle (Germany); Fraunhofer-Institute for Mechanics of Materials, Halle (Germany); Beckers, Thomas; Carius, Reinhard; Rau, Uwe [Institute of Energy and Climate Research 5 - Photovoltaics, Forschungszentrum Juelich GmbH, Juelich (Germany); Fahr, Stefan; Rockstuhl, Carsten; Lederer, Falk [Institute of Condensed Matter Theory and Solid State Optics and Abbe Center of Photonics, Friedrich-Schiller-Universitaet Jena (Germany); Kroll, Matthias; Pertsch, Thomas [Institute of Applied Physics, Friedrich-Schiller-Universitaet Jena (Germany); Steidl, Lorenz; Zentel, Rudolf [Institute of Organic Chemistry, Johannes Gutenberg-Universitaet Mainz (Germany)

    2011-09-08

    A three-dimensional photonic crystal intermediate reflector for enhanced light trapping in tandem solar cells is presented. The intermediate reflector consists of a transparent and conductive ZnO:Al inverted opal sandwiched in between the top amorphous silicon and bottom microcrystalline silicon cell. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. The role of oxide interlayers in back reflector configurations for amorphous silicon solar cells

    NARCIS (Netherlands)

    Demontis, V.; Sanna, C.; Melskens, J.; Santbergen, R.; Smets, A.H.M.; Damiano, A.; Zeman, M.

    2013-01-01

    Thin oxide interlayers are commonly added to the back reflector of thin-film silicon solar cells to increase their current. To gain more insight in the enhancement mechanism, we tested different back reflector designs consisting of aluminium-doped zinc oxide (ZnO:Al) and/or hydrogenated silicon oxid

  12. Self-Mixing Fringes of Vertical-Cavity Surface-Emitting Lasers under Dual Reflector Feedback

    Institute of Scientific and Technical Information of China (English)

    CHENG Xiang; ZHANG Shu-Lian; ZHANG Lian-Qing; TAN Yi-Dong

    2006-01-01

    The self-mixing fringes which shift due to every one-twentieth wavelength displacement of the target are observed.Taking advantage of the dual reflectors in the external cavity of lasers, the resolution of the sensors has been improved by 10 times. The role of the each reflector has been discussed in detail.

  13. Leaky-Wave Slot Array Antenna Fed by a Dual Reflector System

    NARCIS (Netherlands)

    Maci, S.; Ettorre, M.; Neto, A.; Gerini, G.

    2008-01-01

    A leaky-wave slot array antenna fed by a dual offset Gregorian reflector system is realized by pins in a parallel plate waveguide. The radiating part of the antenna is composed by parallel slots etched on one side of the same parallel plate waveguide. The dual offset Gregorian reflector system is fe

  14. 16 CFR Figure 8 to Part 1512 - Reflectorized Bicycle Wheel Rim Abrasion Test Device

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Reflectorized Bicycle Wheel Rim Abrasion... HAZARDOUS SUBSTANCES ACT REGULATIONS REQUIREMENTS FOR BICYCLES Pt. 1512, Fig. 8 Figure 8 to Part 1512—Reflectorized Bicycle Wheel Rim Abrasion Test Device EC03OC91.074...

  15. Theoretical modeling of the dynamics of a semiconductor laser subject to double-reflector optical feedback

    Science.gov (United States)

    Bakry, A.; Abdulrhmann, S.; Ahmed, M.

    2016-06-01

    We theoretically model the dynamics of semiconductor lasers subject to the double-reflector feedback. The proposed model is a new modification of the time-delay rate equations of semiconductor lasers under the optical feedback to account for this type of the double-reflector feedback. We examine the influence of adding the second reflector to dynamical states induced by the single-reflector feedback: periodic oscillations, period doubling, and chaos. Regimes of both short and long external cavities are considered. The present analyses are done using the bifurcation diagram, temporal trajectory, phase portrait, and fast Fourier transform of the laser intensity. We show that adding the second reflector attracts the periodic and perioddoubling oscillations, and chaos induced by the first reflector to a route-to-continuous-wave operation. During this operation, the periodic-oscillation frequency increases with strengthening the optical feedback. We show that the chaos induced by the double-reflector feedback is more irregular than that induced by the single-reflector feedback. The power spectrum of this chaos state does not reflect information on the geometry of the optical system, which then has potential for use in chaotic (secure) optical data encryption.

  16. Concepts for polarising sheets & "dual-gridded" reflectors for circular polarisation

    NARCIS (Netherlands)

    Albani, M.; Balling, P.; Datashvili, L.; Gerini, G.; Ingvarson, P.; Pontoppidan, K.; Sabbadini, M.; Sjöberg, D.; Skokic, S.; Vecchi, G.

    2010-01-01

    C-, Ku- and Ka-band communications and broadcast satellites use so-called dual-gridded reflector antennas for linear polarisation to provide independent reflector surfaces and/or independent feeds for the two orthogonal polarisations. This paper describes initial work to extend this concept to circu

  17. Flexible, angle-independent, structural color reflectors inspired by morpho butterfly wings.

    Science.gov (United States)

    Chung, Kyungjae; Yu, Sunkyu; Heo, Chul-Joon; Shim, Jae Won; Yang, Seung-Man; Han, Moon Gyu; Lee, Hong-Seok; Jin, Yongwan; Lee, Sang Yoon; Park, Namkyoo; Shin, Jung H

    2012-05-08

    Thin-film color reflectors inspired by Morpho butterflies are fabricated. Using a combination of directional deposition, silica microspheres with a wide size distribution, and a PDMS (polydimethylsiloxane) encasing, a large, flexible reflector is created that actually provides better angle-independent color characteristics than Morpho butterflies and which can even be bent and folded freely without losing its Morpho-mimetic photonic properties.

  18. Leaky wave enhanced feeds for multibeam reflectors to be used for telecom satellite based links

    NARCIS (Netherlands)

    Neto, A.; Ettorre, M.; Gerini, G.; Maagt, P. de

    2012-01-01

    The use of dielectric super-layers for shaping the radiation pattern of focal plane feeds of a multibeam reflector system is discussed. Using the super-layers, it is possible to reduce the spillover from the reflectors without increasing the dimension of each aperture. The effect has been demonstrat

  19. Shaped reflector antenna analysis using the Jacobi-Bessel series. [design for space and satellite communication

    Science.gov (United States)

    Rahmat-Samii, Y.; Galindo-Israel, V.

    1980-01-01

    A vector radiation integral is derived for an offset shaped reflector illuminated by an arbitrarily located and oriented source. A procedure for expressing the integral in terms of a series of the Fourier transforms of an effective aperture distribution is discussed. The Jacobi-Bessel series is used to evaluate the Fourier transforms. Numerical results are presented for different reflector configurations and source locations.

  20. Theoretical modeling of the dynamics of a semiconductor laser subject to double-reflector optical feedback

    Energy Technology Data Exchange (ETDEWEB)

    Bakry, A. [King Abdulaziz University, 80203, Department of Physics, Faculty of Science (Saudi Arabia); Abdulrhmann, S. [Jazan University, 114, Department of Physics, Faculty of Sciences (Saudi Arabia); Ahmed, M., E-mail: mostafa.farghal@mu.edu.eg [King Abdulaziz University, 80203, Department of Physics, Faculty of Science (Saudi Arabia)

    2016-06-15

    We theoretically model the dynamics of semiconductor lasers subject to the double-reflector feedback. The proposed model is a new modification of the time-delay rate equations of semiconductor lasers under the optical feedback to account for this type of the double-reflector feedback. We examine the influence of adding the second reflector to dynamical states induced by the single-reflector feedback: periodic oscillations, period doubling, and chaos. Regimes of both short and long external cavities are considered. The present analyses are done using the bifurcation diagram, temporal trajectory, phase portrait, and fast Fourier transform of the laser intensity. We show that adding the second reflector attracts the periodic and perioddoubling oscillations, and chaos induced by the first reflector to a route-to-continuous-wave operation. During this operation, the periodic-oscillation frequency increases with strengthening the optical feedback. We show that the chaos induced by the double-reflector feedback is more irregular than that induced by the single-reflector feedback. The power spectrum of this chaos state does not reflect information on the geometry of the optical system, which then has potential for use in chaotic (secure) optical data encryption.

  1. The role of oxide interlayers in back reflector configurations for amorphous silicon solar cells

    NARCIS (Netherlands)

    Demontis, V.; Sanna, C.; Melskens, J.; Santbergen, R.; Smets, A.H.M.; Damiano, A.; Zeman, M.

    2013-01-01

    Thin oxide interlayers are commonly added to the back reflector of thin-film silicon solar cells to increase their current. To gain more insight in the enhancement mechanism, we tested different back reflector designs consisting of aluminium-doped zinc oxide (ZnO:Al) and/or hydrogenated silicon oxid

  2. Modulation of Transmission Spectra of Anodized Alumina Membrane Distributed Bragg Reflector by Controlling Anodization Temperature

    Directory of Open Access Journals (Sweden)

    Zheng WenJun

    2009-01-01

    Full Text Available Abstract We have successfully prepared anodized alumina membrane distributed Bragg reflector (DBR using electrochemical anodization method. The transmission peak of this distributed Bragg reflector could be easily and effectively modulated to cover almost any wavelength range of the whole visible spectrum by adjusting anodization temperature.

  3. Effect of disc reflectors on radiation impedance of short-backfire antenna

    Science.gov (United States)

    Marougi, S. D.

    1982-02-01

    Using near-field analysis, the influence of large and small disc reflectors used in short-backfire antennas on the radiation impedance of a dipole feed element has been investigated. The effect of each reflector is evaluated separately, and the overall change in the radiation impedance of the dipole is predicted.

  4. The effects of stainless steel radial reflector on core reactivity for small modular reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Jung Kil, E-mail: jkkang@email.kings.ac.kr; Hah, Chang Joo, E-mail: changhah@kings.ac.kr [KINGS, 658-91, Haemaji-ro, Seosaeng-myeon, Ulju-gun, Ulsan, 689-882 (Korea, Republic of); Cho, Sung Ju, E-mail: sungju@knfc.co.kr; Seong, Ki Bong, E-mail: kbseong@knfc.co.kr [KNFC, Daedeok-daero 989beon-gil, Yuseong-gu, Daejeon, 305-353 (Korea, Republic of)

    2016-01-22

    Commercial PWR core is surrounded by a radial reflector, which consists of a baffle and water. Radial reflector is designed to reflect neutron back into the core region to improve the neutron efficiency of the reactor and to protect the reactor vessels from the embrittling effects caused by irradiation during power operation. Reflector also helps to flatten the neutron flux and power distributions in the reactor core. The conceptual nuclear design for boron-free small modular reactor (SMR) under development in Korea requires to have the cycle length of 4∼5 years, rated power of 180 MWth and enrichment less than 5 w/o. The aim of this paper is to analyze the effects of stainless steel radial reflector on the performance of the SMR using UO{sub 2} fuels. Three types of reflectors such as water, water/stainless steel 304 mixture and stainless steel 304 are selected to investigate the effect on core reactivity. Additionally, the thickness of stainless steel and double layer reflector type are also investigated. CASMO-4/SIMULATE-3 code system is used for this analysis. The results of analysis show that single layer stainless steel reflector is the most efficient reflector.

  5. Hierarchical Orbital Observatory Deployable Shroud (HOODS) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Large deployable telescopes such as NASA's 9.2m and 16.8m segmented ATLAST systems require commensurately large deployable sunshades for thermal control and to...

  6. Design and Fabrication of Integrated Fabry-Perot Type Color Reflector for Reflective Displays.

    Science.gov (United States)

    Cho, Seong M; Cheon, Sang Hoon; Kim, Tae-Youb; Ah, Chil Seong; Song, Juhee; Ryu, Hojun; Chu, Hye Yong

    2016-05-01

    A Fabry-Perot type integrated color reflector, with red/blue/green colors as subpixels, was designed and fabricated with Si substrate. Ag films were used as reflective mirror layers, SiO2 films were used as Fabry-Perot cavity layers and W films were used as partially reflective layers for the cavity. To minimize the effects of the thickness variation of the oxide cavity layers, the structure of the color reflector was optimized, and the differential deposition scheme was devised and applied in the fabrication process. The integrated color reflector was successfully fabricated with the proposed fabrication scheme. The measured white reflectance was > 45% in the visible spectrum range and -49% at 550 nm wavelength. The fabricated reflector had moderate color gamut of 17% of the National Television System Committee (NTSC) standard and it showed very high white reflectivity. The fabricated color reflector is expected to be applicable to reflective displays.

  7. Generation of XS library for the reflector of VVER reactor core using Monte Carlo code Serpent

    Science.gov (United States)

    Usheva, K. I.; Kuten, S. A.; Khruschinsky, A. A.; Babichev, L. F.

    2017-01-01

    A physical model of the radial and axial reflector of VVER-1200-like reactor core has been developed. Five types of radial reflector with different material composition exist for the VVER reactor core and 1D and 2D models were developed for all of them. Axial top and bottom reflectors are described by the 1D model. A two-group XS library for diffusion code DYN3D has been generated for all types of reflectors by using Serpent 2 Monte Carlo code. Power distribution in the reactor core calculated in DYN3D is flattened in the core central region to more extent in the 2D model of the radial reflector than in its 1D model.

  8. Weighted SAW reflector gratings for orthogonal frequency coded SAW tags and sensors

    Science.gov (United States)

    Puccio, Derek (Inventor); Malocha, Donald (Inventor)

    2011-01-01

    Weighted surface acoustic wave reflector gratings for coding identification tags and sensors to enable unique sensor operation and identification for a multi-sensor environment. In an embodiment, the weighted reflectors are variable while in another embodiment the reflector gratings are apodized. The weighting technique allows the designer to decrease reflectively and allows for more chips to be implemented in a device and, consequently, more coding diversity. As a result, more tags and sensors can be implemented using a given bandwidth when compared with uniform reflectors. Use of weighted reflector gratings with OFC makes various phase shifting schemes possible, such as in-phase and quadrature implementations of coded waveforms resulting in reduced device size and increased coding.

  9. Positive focal shift of gallium nitride high contrast grating focusing reflectors

    Science.gov (United States)

    He, Shumin; Wang, Zhenhai; Liu, Qifa

    2016-09-01

    We design a type of metasurfaces capable of serving as a visible-light focusing reflector based on gallium nitride (GaN) high contrast gratings (HCGs). The wavefront of the reflected light is precisely manipulated by spatial variation of the grating periods along the subwavelength ridge array to achieve light focusing. Different from conventional negative focal shift effect, a positive focal shift is observed in such focusing reflectors. Detailed investigations of the influence of device size on the focusing performance, especially the focal length, are preformed via a finite element method . The results show that all performance parameters are greatly affected by the reflector size. A more concentrated focal point, or a better focusing capability, can be achieved by larger size. With increasing reflector size, the achieved focal length decreases and gradually approaches to the design, thus the corresponding positive focal shift decreases. Our results are helpful for understanding the visible-light control of the planar HCG-based focusing reflectors.

  10. PCM Heat Storage Charged with a Double-Reflector Solar System

    Directory of Open Access Journals (Sweden)

    Amos Veremachi

    2016-01-01

    Full Text Available A “Solar Salt” (NaNO3–KNO3 60 : 40 molar mixture latent heat storage has been charged by direct solar illumination. Solar Salt as a Phase Change Material (PCM can be an attractive small scale heat storage solution, as the melting temperature of about 220°C can be suitable for cooking purposes. The tests were made with a double-reflector setup. In this setup a secondary reflector positioned above the focal point of the primary reflector directs the rays onto a heat storage positioned below a hole in the primary reflector. The reflectors are tracking the sun, but the storage is stationary. The direct illumination of the absorber top plate during the tracking of the sun melted the salt in the storage through conducting fins. This is a system where portable heat batteries can be charged, during sunshine hours, and then provide heat for cooking during evening times.

  11. Security Support in Continuous Deployment Pipeline

    DEFF Research Database (Denmark)

    Ullah, Faheem; Raft, Adam Johannes; Shahin, Mojtaba

    2017-01-01

    Continuous Deployment (CD) has emerged as a new practice in the software industry to continuously and automatically deploy software changes into production. Continuous Deployment Pipeline (CDP) supports CD practice by transferring the changes from the repository to production. Since most of the C...

  12. Galicia3D seismic volume: Connections between the western termination of the S reflector and eastern termination of the Peridotite Ridge

    Science.gov (United States)

    Sawyer, Dale; Jordan, Brian; Morgan, Julia; Shillington, Donna; Reston, Timothy; Ranero, Cesar

    2015-04-01

    In June thru September, 2013, a 3D reflection and a long offset seismic experiment were conducted at the Galicia rifted margin by investigators from the US, UK, Germany, and Spain. The 3D multichannel experiment covered 64 km by 20 km (1280 km2), using the RV Marcus Langseth. Four streamers 6 km long were deployed at 12.5 m hydrophone channel spacing. The streamers were 200 m apart. Two airgun arrays, each 3300 cu in, were fired alternately every 37.5 m, to collectively yield a 400 m wide sail line consisting of 8 CMP lines at 50 m spacing. We draw attention to the region from the Peridotite Ridge, PR, (on the west) and the western terminus of the S reflector (on the east). The S reflector is generally thought to separate continental crust and pre- and syn-rift sediment above, and serpentinized upper mantle below. In 2D and 3D seismic reflection data, the S reflector is very bright, generally horizontal, and is terminated very abruptly at the western end. The latter is particularly clear in the 3D volume. It is about 10-15 km wide between the end of the S reflector and the midpoint of the PR. In this interval, there appear to be fault bounded blocks that may be either continental crust or pre- or syn-rift sediments. The PR is a virtually straight, N-S ridge, without apparent fault offsets. The crest of the PR is at about 4800 mbsl at the S extent and is at 6070 mbsl at the N extent of the 3D volume. The crest is approximately linear in map view or N-S extent. Both sides, East and West of the PR, appear to show landslides and other mass wasting during the late stage of the syn-rifting interval. The PR rarely shows internal seismic structure in 2D and 3D. Most importantly, under the basin to the east of the PR there are substantially more recognizable structures connecting the S reflector and the PR. These were much less interpretable in previous 2D seismic profiles.

  13. Photogrammetry research for FAST eleven-meter reflector panel surface shape measurement

    Science.gov (United States)

    Zhou, Rongwei; Zhu, Lichun; Li, Weimin; Hu, Jingwen; Zhai, Xuebing

    2010-10-01

    In order to design and manufacture the Five-hundred-meter Aperture Spherical Radio Telescope (FAST) active reflector measuring equipment, measurement on each reflector panel surface shape was presented, static measurement of the whole neutral spherical network of nodes was performed, real-time dynamic measurement at the cable network dynamic deformation was undertaken. In the implementation process of the FAST, reflector panel surface shape detection was completed before eleven-meter reflector panel installation. Binocular vision system was constructed based on the method of binocular stereo vision in machine vision, eleven-meter reflector panel surface shape was measured with photogrammetry method. Cameras were calibrated with the feature points. Under the linearity camera model, the lighting spot array was used as calibration standard pattern, and the intrinsic and extrinsic parameters were acquired. The images were collected for digital image processing and analyzing with two cameras, feature points were extracted with the detection algorithm of characteristic points, and those characteristic points were matched based on epipolar constraint method. Three-dimensional reconstruction coordinates of feature points were analyzed and reflective panel surface shape structure was established by curve and surface fitting method. The error of reflector panel surface shape was calculated to realize automatic measurement on reflector panel surface shape. The results show that unit reflector panel surface inspection accuracy was 2.30mm, within the standard deviation error of 5.00mm. Compared with the requirement of reflector panel machining precision, photogrammetry has fine precision and operation feasibility on eleven-meter reflector panel surface shape measurement for FAST.

  14. Development and testing of the pneumatic lunar drill for the emplacement of the corner cube reflector on the Moon

    Science.gov (United States)

    Zacny, K.; Currie, D.; Paulsen, G.; Szwarc, T.; Chu, P.

    2012-10-01

    Lunar Laser Ranging provides a highly accurate measurement of the distance between ground stations on Earth and reflectors on the surface of the Moon. Since retroreflectors were initially placed during the Apollo missions, the ground stations improved the ranging accuracy by a factor of 200 and now the Apollo-era arrays on the Moon pose a significant limitation to the ranging accuracy. The new Lunar Laser Ranging Retroreflector (i.e. the Lunar Laser Ranging retroreflector for the 21st century or LLRRA-21) would provide extensive new information on the lunar interior, general relativity, and cosmology. During the day/night lunar cycle, when the thermal variation of the surface is approximately 300 °C, the regolith will rise and fall by almost 500 μm. Yet, it is estimated that the thermal variation 0.5 m to 1 m below the surface is less than much 1 °C. Thus for the lunar emplacement to support 10s of microns ranging accuracy, the reflectors must be anchored to that thermally stable mass at 0.5 m or greater depth. In this paper, we present a novel method of deploying LLRRA-21 with a Corner Cube Reflector (CCR) on the Moon. The emplacement approach uses a gas-powered drill consisting of a >50 cm long, slim, hollow rod with a perforated anchor-cone at its lower end and the CCR mounted to the top. Gas supplied from a small tank is directed into and down the rod and out through the cone, lofting the soil out of the hole and allowing the rod to sink under its own weight to a depth of 0.5 m. To determine the system performance, we conducted several tests in compacted JSC-1a lunar soil simulant and inside a vacuum chamber. In several tests, the rod successfully sunk under its own weight of 16 N to a depth of 50 cm in 4-6 min. The pneumatic system is the game-changer for subsurface access. The extremely low mass and volume required to reach 50 cm, along with very simple penetration method allow the CCR to remain in a variety of payload architectures.

  15. Study on differences between high contrast grating reflectors for TM and TE polarizations and their impact on VCSEL designs

    DEFF Research Database (Denmark)

    Chung, Il-Sug

    2015-01-01

    A theoretical study of differences in broadband high-indexcontrast grating (HCG) reflectors for TM and TE polarizations is presented, covering various grating parameters and properties of HCGs. It is shown that the HCG reflectors for TM polarization (TM HCG reflectors) have much thicker grating...

  16. RSG Deployment Case Testing Results

    Energy Technology Data Exchange (ETDEWEB)

    Owsley, Stanley L.; Dodson, Michael G.; Hatchell, Brian K.; Seim, Thomas A.; Alexander, David L.; Hawthorne, Woodrow T.

    2005-09-01

    The RSG deployment case design is centered on taking the RSG system and producing a transport case that houses the RSG in a safe and controlled manner for transport. The transport case was driven by two conflicting constraints, first that the case be as light as possible, and second that it meet a stringent list of Military Specified requirements. The design team worked to extract every bit of weight from the design while striving to meet the rigorous Mil-Spec constraints. In the end compromises were made primarily on the specification side to control the overall weight of the transport case. This report outlines the case testing results.

  17. Study of the Dynamics of Large Reflector Antennas with Accelerometers

    CERN Document Server

    Snel, R C; Baars, J W M

    2007-01-01

    The Atacama Large Millimeter Array (ALMA) will consist of up to 64 state-of-the-art sub-mm telescopes, subject to stringent performance specifications which will push the boundaries of the technology, and makes testing of antenna performance a likewise challenging task. Two antenna prototypes were evaluated at the ALMA Test Facility at the Very Large Array site in New Mexico, USA. The dynamic behaviour of the antennas under operational conditions was investigated with the help of an accelerometer system capable of measuring rigid body motion of the elevation structure of the antenna, as well as a few low-order deformation modes, resulting in dynamic performance numbers for pointing stability, reflector surface stability, path length stability, and structure flexure. Special emphasis was given to wind effects, one of the major factors affecting performance on timescales of seconds to tens of minutes. This paper describes the accelerometer system, its capabilities and limitations, and presents the dynamic perfo...

  18. Photoacoustic imaging using acoustic reflectors to enhance planar arrays.

    Science.gov (United States)

    Ellwood, Robert; Zhang, Edward; Beard, Paul; Cox, Ben

    2014-12-01

    Planar sensor arrays have advantages when used for photoacoustic imaging: they do not require the imaging target to be enclosed, and they are easier to manufacture than curved arrays. However, planar arrays have a limited view of the acoustic field due to their finite size; therefore, not all of the acoustic waves emitted from a photoacoustic source can be recorded. This loss of data results in artifacts in the reconstructed photoacoustic image. A detection array configuration which combines a planar Fabry–Pérot sensor with perpendicular acoustic reflectors is described and experimentally implemented. This retains the detection advantages of the planar sensor while increasing the effective detection aperture in order to improve the reconstructed photoacoustic image.

  19. Multiphysics modeling and uncertainty quantification for an active composite reflector

    Science.gov (United States)

    Peterson, Lee D.; Bradford, S. C.; Schiermeier, John E.; Agnes, Gregory S.; Basinger, Scott A.

    2013-09-01

    A multiphysics, high resolution simulation of an actively controlled, composite reflector panel is developed to extrapolate from ground test results to flight performance. The subject test article has previously demonstrated sub-micron corrected shape in a controlled laboratory thermal load. This paper develops a model of the on-orbit performance of the panel under realistic thermal loads, with an active heater control system, and performs an uncertainty quantification of the predicted response. The primary contribution of this paper is the first reported application of the Sandia developed Sierra mechanics simulation tools to a spacecraft multiphysics simulation of a closed-loop system, including uncertainty quantification. The simulation was developed so as to have sufficient resolution to capture the residual panel shape error that remains after the thermal and mechanical control loops are closed. An uncertainty quantification analysis was performed to assess the predicted tolerance in the closed-loop wavefront error. Key tools used for the uncertainty quantification are also described.

  20. Dual-Band Feed for a Microwave Reflector Antenna

    Science.gov (United States)

    Hoppe, Daniel; Reilly, Harry

    2005-01-01

    A waveguide feed has been designed to provide specified illumination patterns for a dual-reflector antenna in two wavelength bands: 8 to 9 GHz and 30 to 40 GHz. The feed (see figure) has a coaxial configuration: A wider circular tube surrounds a narrower circular tube that serves as a waveguide for the signals in the 30-to-40-GHz band. The annular space between the narrower and the wider tube serves as a coaxial waveguide for the signals in the 8-to-9-GHz band. The nominal design frequencies of the outer and inner waveguides are 8.45 and 32 GHz, respectively. Each of the two waveguides is terminated in a component that is sized and shaped to help focus the radiation in its respective frequency band into the specified illumination pattern. For the outer waveguide, the beam-shaping termination is a corrugated horn; for the inner waveguide, the beam-shaping termination is a dielectric rod insert.

  1. Compact Single-Mode Distributed Bragg Reflector Fiber Laser

    Institute of Scientific and Technical Information of China (English)

    XUE Yi-Yuan; AN Hong-Lin; FU Li-Bin; LIN Xiang-Zhi; LIU Hong-Du

    2000-01-01

    A compact single-mode distributed Bragg reflector (DBR) fiber laser with narrow spectral linewidth is investigated. Firstly, based on our theoretical analysis the single longitudinal mode operation domain is obtained. Then, a single-mode DBR fiber laser of 7.9cm long with master oscillator power amplifier (MOPA) configuration is designed and constructed to operate in the single-mode domain. The fiber laser is pumped by a semiconductor laser at 975.5nm. The master oscillator operates at 1556.91 nm with a cw output power of 1.43mW for a pump power of 55.35 mW. Its slope efficiency is 2.7% and the spectral linewidth is less than 1.2MHz (instrument resolution limited). With the MOPA configuration the laser output power and slope efficiency are increased to 7.8mW and 16.9%, respectively.

  2. Investigation of Flexible Textile Antennas and AMC Reflectors

    Directory of Open Access Journals (Sweden)

    M. Mantash

    2012-01-01

    Full Text Available In this paper, two different methods for fabric characterization are presented: a single frequency method and a broadband method. Felt and denim fabrics are characterized, and patch antennas are designed using these substrates to test both methods. Prototypes of the antennas on felt and denim are manufactured using conductive textile (called electrotextile aiming to obtain fully flexible antennas. The prototypes are characterized in anechoic chamber to be compared and obtain conclusions related to the characterization methods. A new dual-band hexagonal AMC reflector combinable with antennas is also proposed to improve their performance and reduce the backward radiation to the human body. A novel broadband CPW-fed monopole antenna is designed to be combined with the AMC. The resulted prototype is characterized and compared with the performance of the CPW-fed antenna alone.

  3. System overview on electromagnetic compensation for reflector antenna surface distortion

    Science.gov (United States)

    Acosta, R. J.; Zaman, A. J.; Terry, J. D.

    1993-01-01

    The system requirements and hardware implementation for electromagnetic compensation of antenna performance degradations due to thermal effects was investigated. Future commercial space communication antenna systems will utilize the 20/30 GHz frequency spectrum and support very narrow multiple beams (0.3 deg) over wide angle field of view (15-20 beamwidth). On the ground, portable and inexpensive very small aperture terminals (VSAT) for transmitting and receiving video, facsimile and data will be employed. These types of communication system puts a very stringent requirement on spacecraft antenna beam pointing stability (less than .01 deg), high gain (greater than 50 dB) and very lowside lobes (less than -25 dB). Thermal analysis performed on the advanced communication technology satellite (ACTS) has shown that the reflector surfaces, the mechanical supporting structures and metallic surfaces on the spacecraft body will distort due thermal effects from a varying solar flux. The antenna performance characteristics (e.g., pointing stability, gain, side lobe, etc.) will degrade due to thermal distortion in the reflector surface and supporting structures. Specifically, antenna RF radiation analysis has shown that pointing error is the most sensitive antenna performance parameter to thermal distortions. Other antenna parameters like peak gain, cross polarization level (beam isolation), and side lobe level will also degrade with thermal distortions. In order to restore pointing stability and in general antenna performance several compensation methods were proposed. In general these compensation methods can be classified as being either of mechanical or electromagnetic type. This paper will address only the later one. In this approach an adaptive phased array antenna feed is used to compensate for the antenna performance degradation. Extensive work has been devoted to demonstrate the feasibility of adaptive feed compensation on space communication antenna systems. This

  4. TU-AB-201-11: A Novel Theoretical Framework for MRI-Only Image Guided LDR Prostate and Breast Brachytherapy Implant Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Soliman, A; Elzibak, A; Fatemi, A; Safigholi, H; Ravi, A; Morton, G; Song, W [Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario (Canada); Han, D [Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario (Canada); University of California, San Diego, La Jolla, CA (United States)

    2015-06-15

    Purpose: To propose a novel framework for accurate model-based dose calculations using only MR images for LDR prostate and breast seed implant brachytherapy. Methods: Model-based dose calculation methodologies recommended by TG-186 require further knowledge about specific tissue composition, which is challenging with MRI. However, relying on MRI-only for implant dosimetry would reduce the soft tissue delineation uncertainty, costs, and uncertainties associated with multi-modality registration and fusion processes. We propose a novel framework to address this problem using quantitative MRI acquisitions and reconstruction techniques. The framework includes three steps: (1) Identify the locations of seeds(2) Identify the presence (or absence) of calcification(s)(3) Quantify the water and fat content in the underlying tissueSteps (1) and (2) consider the sources that limit patient dosimetry, particularly the inter-seed attenuation and the calcified regions; while step (3) targets the quantification of the tissue composition to consider the heterogeneities in the medium. Our preliminary work has shown that the seeds and the calcifications can be identified with MRI using both the magnitude and the phase images. By employing susceptibility-weighted imaging with specific post-processing techniques, the phase images can be further explored to distinguish the seeds from the calcifications. Absolute quantification of tissue, water, and fat content is feasible and was previously demonstrated in phantoms and in-vivo applications, particularly for brain diseases. The approach relies on the proportionality of the MR signal to the number of protons in an image volume. By employing appropriate correction algorithms for T1 - and T2*-related biases, B1 transmit and receive field inhomogeneities, absolute water/fat content can be determined. Results: By considering calcification and interseed attenuation, and through the knowledge of water and fat mass density, accurate patient

  5. Large Antenna Control Methods: Current Status and Future Trends

    Science.gov (United States)

    Rodriguez, G.; Lin, Y. H.; Milman, M. H.

    1985-01-01

    Current methods for control of large antennas, as well as future trends required for improved performance are addressed. Some of the target missions in which these methods would be used are: the Land Mobile Satellite System (LMSS) for communications; the Satellite Surveillance (SSS) for aircraft traffic control; the orbiting Very Long Baseline Interferometer (VLBI), or QUASAT, for radio astronomy; and the Large Deployable Reflector (LDR) for IR and submillimeter astronomy.

  6. Comparison of electrohydraulic lithotripters with rigid and pressure-release ellipsoidal reflectors. II. Cavitation fields.

    Science.gov (United States)

    Bailey, M R; Blackstock, D T; Cleveland, R O; Crum, L A

    1999-08-01

    Dramatically different cavitation was produced by two separate acoustic pulses that had different shapes but similar duration, frequency content, and peak positive and negative pressure. Both pulses were produced by a Dornier HM-3 style lithotripter: one pulse when the ellipsoidal reflector was rigid, the other when the reflector was pressure release. The cavitation, or bubble action, generated by the conventional rigid-reflector pulse was nearly 50 times longer lived and 3-13 times stronger than that produced by the pressure-release-reflector pulse. Cavitation durations measured by passive acoustic detection and high-speed video agreed with calculations based on the Gilmore equation. Cavitation intensity, or destructive potential, was judged (1) experimentally by the size of pits in aluminum foil detectors and (2) numerically by the calculated amplitude of the shock wave emitted by a collapsing bubble. The results indicate that the trailing positive spike in the pressure-release-reflector waveform stifles bubble growth and mitigates the collapse, whereas the trough after the positive spike in the rigid-reflector waveform triggers inertially driven growth and collapse. The two reflectors therefore provide a tool to compare effects in weakly and strongly cavitating fields and thereby help assess cavitation's role in lithotripsy.

  7. The Effect of Reflector with Sound-Absorbing Material on Supersonic Jet Noise

    Institute of Scientific and Technical Information of China (English)

    Y.-H. KWEON; M. TSUCHIDA; Y. MIYAZATO; T. AOKI; H.-D. KIM; T. SETOGUCHI

    2005-01-01

    This paper describes an experimental work to investigate the effect of a reflector on supersonic jet noise radiated from a convergent-divergent nozzle with a design Mach number 2.0. In the present study, a metal reflector and reflectors made of three different sound-absorbing materials (grass wool and polyurethane foam) were employed,and the reflector size was varied. Acoustic measurement is carried out to obtain the acoustic characteristics such as frequency, amplitude of screech tone and overall sound pressure level (OASPL). A high-quality schlieren optical system is used to visualize the detailed structure of supersonic jet. The results obtained show that the acoustic characteristics of supersonic jet noise are strongly dependent upon the jet pressure ratio and the reflector size. It is also found that the reflector with sound-absorbing material reduces the screech tone amplitude by about 5-13dB and the overall sound pressure levels by about 2-5dB, compared with those of the metal reflector.

  8. Optimization design of an adaptive CFRC reflector for high order wave-front error control

    Science.gov (United States)

    Lan, Lan; Fang, Houfei; Wu, Ke; Jiang, Shuidong; Zhou, Yang

    2017-04-01

    The trend in future space high precision reflectors is going towards large aperture, lightweight and actively controlled deformable antennas. An adaptive shape control system for a Carbon Fiber Reinforced Composite (CFRC) reflector is conducted by Piezoelectric Ceramic Transducer (PZT) actuators. This adaptive shape control system has been shown to effectively mitigate common low order wave-front error, but it is inevitably plagued by high order wave-front error control. In order to improve the controllability of the adaptive CFRC reflector control system for high order wave-front error, the design of adaptive CFRC reflector requires optimizing further. According to numerical and experimental results, the print-through error induced by manufacturing and PZT actuators actuation is a type of predominant high order wave-front error. This paper describes a design which some secondary rib elements are embedded within the triangular cells of the primary ribs. These small secondary ribs are designed to support the reflector surface's weak region. Controllability of this new adaptive CFRC reflector control system with small secondary ribs is evaluated by generalized Zernike functions. This new design scheme can reduce high order residual error and suppress the high order wave-front error such as print-through error. Finally, design parameters of the adaptive CFRC reflector control system with small secondary ribs, such as primary rib height, secondary rib height, cut-out height of primary rib, are optimized.

  9. Performance Study of a Double-Pass Thermoelectric Solar Air Collector with Flat-Plate Reflectors

    Science.gov (United States)

    Lertsatitthanakorn, C.; Rungsiyopas, M.; Therdyothin, A.; Soponronnarit, S.

    2012-06-01

    In this paper the results of the influence of flat-plate reflectors made of aluminum foil on the performance of a double-pass thermoelectric (TE) solar air collector are presented. The proposed TE solar collector with reflectors was composed of transparent glass, an air gap, an absorber plate, TE modules, a rectangular fin heat sink, and two flat-plate reflectors. The flat-plate reflectors were placed on two sides of the TE solar collector (east and west directions). The TE solar collector was installed on a one-axis sun-tracking system to obtain high solar radiation. Direct and reflected incident solar radiation heats up the absorber plate so that a temperature difference is created across the TE modules to generate a direct current. Only a small part of the absorbed solar radiation is converted to electricity, while the rest increases the temperature of the absorber plate. Ambient air flows through the heat sink located in the lower channel to gain heat. The heated air then flows to the upper channel, where it receives additional heating from the absorber plate. Improvements to the thermal energy and electrical power outputs of the system can be achieved by the use of the double-pass collector system with reflectors and TE technology. It was found that the optimum position of the reflectors is 60°, which gave significantly higher thermal energy and electrical power outputs compared with the TE solar collector without reflectors.

  10. Electrically switchable polymer stabilised broadband infrared reflectors and their potential as smart windows for energy saving in buildings

    Science.gov (United States)

    Khandelwal, Hitesh; Loonen, Roel C. G. M.; Hensen, Jan L. M.; Debije, Michael G.; Schenning, Albertus P. H. J.

    2015-07-01

    Electrically switchable broadband infrared reflectors that are relatively transparent in the visible region have been fabricated using polymer stabilised cholesteric liquid crystals. The IR reflectors can change their reflection/transmission properties by applying a voltage in response to changes in environmental conditions. Simulations predict that a significant amount of energy can be saved on heating, cooling and lighting of buildings in places such as Madrid by using this switchable IR reflector. We have also fabricated a switchable IR reflector which can also generate electricity. These polymer based switchable IR reflectors are of high potential as windows of automobiles and buildings to control interior temperatures and save energy.

  11. Optimization of a dielectric radome for a dual-reflector omnidirectional antenna

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.

    2001-01-01

    In the millimetre-wave range, cylindrical dielectric insertions are employed to support a subreflector and, at the same time, as a radome of a dual-reflector omnidirectional antenna. Such a dielectric discontinuity can substantially degrade both matching and radiation characteristics of the antenna....... Until recently, the problem of optimization of a dielectric radome was solved experimentally due to a lack of methods that allow the VSWR of a dual-reflector omnidirectional antenna to be calculated taking into account the dielectric insertions. This paper presents a numerical approach to select...... the parameters of a dielectric radome for a dual-reflector omnidirectional antenna....

  12. PO Analysis for RCS of Nonorthogonal Dihedral Corner Reflectors Coated by RAM

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The backscattering radar cross section (RCS) of nonorthogonal dihedral corner reflectors coated by RAM (radar absorbing materials) is formulated by the method of PO (physical optics), where singly, doubly, and triply reflected contributions are considered. The final expressions are analytical and allow for the incidence nonperpendicular to the fold axis of the reflector. The results are compared with ones of MoM (method of moment), which shows that the trend of backscatter patterr of the dihedral corner reflector can be well predicted by this method.

  13. A Study of the Fitting Accuracy of the Active Reflector for a Large Spherical Radio Telescope

    Institute of Scientific and Technical Information of China (English)

    Xiao-Qiang Tang; Jin-Song Wang; Qi-Ming Wang

    2003-01-01

    We propose a spatial three-degree-of-freedom (DOF) parallel mechanism combining two degrees of rotations and one degree of translation to support the active reflector units of a large spherical radio telescope. The kinematics, workspace and accuracy of the mechanism are analyzed. One-dimensional and two-dimensional fitting errors to the working region of active reflector are investigated. Dimensional parameters of the mechanism and active reflector unit are examined with respect to the requirement of fitting accuracy. The result of accuracy analysis shows the effectiveness and feasibility of the proposed mechanism, and gives a design rule to guarantee the highest working frequency required by large radio telescope.

  14. Diffraction-resistant scalar beams generated by a parabolic reflector and a source of spherical waves.

    Science.gov (United States)

    Zamboni-Rached, Michel; de Assis, Mariana Carolina; Ambrosio, Leonardo A

    2015-07-01

    In this work, we propose the generation of diffraction-resistant beams by using a parabolic reflector and a source of spherical waves positioned at a point slightly displaced from its focus (away from the reflector). In our analysis, considering the reflector dimensions much greater than the wavelength, we describe the main characteristics of the resulting beams, showing their properties of resistance to the diffraction effects. Due to its simplicity, this method may be an interesting alternative for the generation of long-range diffraction-resistant waves.

  15. Diffraction Resistant Scalar Beams Generated by a Parabolic Reflector and a Source of Spherical Waves

    CERN Document Server

    Zamboni-Rached, Michel; Ambrosio, Leonardo A

    2015-01-01

    In this work, we propose the generation of diffraction resistant beams by using a parabolic reflector and a source of spherical waves positioned at a point slightly displaced from its focus (away from the reflector). In our analysis, considering the reflector dimensions much greater than the wavelength, we describe the main characteristics of the resulting beams, showing their properties of resistance to the diffraction effects. Due to its simplicity, this method may be an interesting alternative for the generation of long range diffraction resistant waves.

  16. Observations on the linear programming formulation of the single reflector design problem.

    Science.gov (United States)

    Canavesi, Cristina; Cassarly, William J; Rolland, Jannick P

    2012-02-13

    We implemented the linear programming approach proposed by Oliker and by Wang to solve the single reflector problem for a point source and a far-field target. The algorithm was shown to produce solutions that aim the input rays at the intersections between neighboring reflectors. This feature makes it possible to obtain the same reflector with a low number of rays - of the order of the number of targets - as with a high number of rays, greatly reducing the computation complexity of the problem.

  17. Effect of tone mapping operators on visual attention deployment

    Science.gov (United States)

    Narwaria, Manish; Perreira Da Silva, Matthieu; Le Callet, Patrick; Pepion, Romuald

    2012-10-01

    High Dynamic Range (HDR) images/videos require the use of a tone mapping operator (TMO) when visualized on Low Dynamic Range (LDR) displays. From an artistic intention point of view, TMOs are not necessarily transparent and might induce different behavior to view the content. In this paper, we investigate and quantify how TMOs modify visual attention (VA). To that end both objective and subjective tests in the form of eye-tracking experiments have been conducted on several still image content that have been processed by 11 different TMOs. Our studies confirm that TMOs can indeed modify human attention and fixation behavior significantly. Therefore our studies suggest that VA needs consideration for evaluating the overall perceptual impact of TMOs on HDR content. Since the existing studies so far have only considered the quality or aesthetic appeal angle, this study brings in a new perspective regarding the importance of VA in HDR content processing for visualization on LDR displays.

  18. Pre-deployment Year Mental Health Diagnoses and Treatment in Deployed Army Women.

    Science.gov (United States)

    Wooten, Nikki R; Adams, Rachel Sayko; Mohr, Beth A; Jeffery, Diana D; Funk, Wendy; Williams, Thomas V; Larson, Mary Jo

    2016-07-01

    We estimated the prevalence of select mental health diagnoses (MHDX) and mental health treatment (MHT), and identified characteristics associated with MHT during the pre-deployment year (365 days before deployment) in active duty Army women (N = 14,633) who returned from Iraq or Afghanistan deployments in FY2010. Pre-deployment year prevalence estimates were: 26.2 % for any select MHDX and 18.1 % for any MHT. Army women who had physical injuries since FY2002 or any behavioral health treatment between FY2002 and the pre-deployment year had increased odds of pre-deployment year MHT. During the pre-deployment year, a substantial percentage of Army women had MHDX and at least one MHT encounter or stay. Future research should determine if pre-deployment MHDX among Army women reflect vulnerability to future MHDX, or if pre-deployment MHT results in protection from chronic symptoms.

  19. Mapping sub-crustal reflectors in southwestern Spain

    Science.gov (United States)

    Palomeras, I.; Ayarza, P.; Carbonell, R.; Ehsan, S. A.; Afonso, J. C.; Diaz Cusi, J.

    2015-12-01

    During the last 15 years, the IBERSEIS and ALCUDIA controlled source experiments have acquired vertical incidence and wide angle seismic reflection data in southwest Spain, in the Variscan Sub-Portuguese, Ossa-Morena and Central-Iberian Zones. Apart from providing detailed information of the crust, these datasets have also imaged a conspicuous sub-crustal reflector. First identified on the IBERSEIS wide-angle reflection dataset, this interface seemed to feature a positive seismic impedance contrast. A boundary located between 61-72 km depth, with a Vp increase from 8.2 km/s to 8.3 km/s allowed us to model clear wide-angle reflections found above 180 km offsets. The fact that this reflector was not identified in the coincident vertical incidence dataset led us to interpret it as a gradient zone. A correlation with the 'Hales gradient zone', i.e. the boundary between spinel and garnet peridotites was our preferred interpretation. The ALCUDIA experiment, later acquired northwards of the IBERSEIS profiles, also shows prominent sub-crustal arrivals with the same characteristics as those observed in the IBERSEIS wide-angle data. However, these reflections also appear, locally and at 19 s TWT, in the vertical incidence dataset, further constraining the depth at which this feature is located. In addition, the ALCUDIA wide-angle dataset shows deeper sub-horizontal reflectivity (at Vred=8 km/s) that maybe preliminarily associated with mantle anisotropy or even, with the lithosphere-astenosphere boundary. Integration of the information provided by the IBERSEIS and ALCUDIA datasets with older and lower resolution data from the ILIHA project, where three sub-crustal phases were identified in SW Iberia, allows us to conclude that, in this area, mantle reflectivity is outstanding. Also, modeling of all the datasets contributes to map, at a regional scale, the Hales discontinuity or gradient zone in southwest Iberia. Further research, involving receiver function analysis is

  20. Tow-Dimensionally Deployable "SHDF" Truss

    OpenAIRE

    ONODA, Junjiro; WATANABE, Naoyudi; Ichida, Kazuo; HASHIMOTO, Yasuo; NAKADA, Atsushi; Saito, Hisashi; 小野田, 淳次郎

    1988-01-01

    The present paper describes a newly invented two-dimensionally deployable truss structure named SHDF, which has no articulated members. The most significant feature of SHDF truss is the very small number of the mechanisms to be actuated and locked at the deployment. A globally flat functional model actuated by tiny electromagnetic motors was designed and fabricated. The model demonstrated its practicality and virtually synchronized smooth motion in deploy/fold tests. Subsequently, the model w...

  1. Phoenix Metropolitan Model Deployment Initiative Evaluation Report

    OpenAIRE

    Zimmerman, C; Marks, J.; Jenq, J.; Cluett, Chris; DeBlasio, Allan; Lappin, Jane; Rakha, Hesham A.; Wunderlich, K

    2000-01-01

    This report presents the evaluation results of the Phoenix, Arizona Metropolitan Model Deployment Initiative (MMDI). The MMDI was a three-year program of the Intelligent Transportation Systems (ITS) Joint Program Office of the U.S. Department of Transportation. It focused on aggressive deployment of ITS at four sites across the United States, including the metropolitan areas of San Antonio, Seattle, NY/NJ/Connecticut as well as Phoenix. The focus of the deployments was on integration of exist...

  2. Deployable and retractable telescoping tubular structure development

    Science.gov (United States)

    Thomson, M. W.

    1994-01-01

    A new deployable and retractable telescoping boom capable of high deployed stiffness and strength is described. Deployment and retraction functions are controlled by simple, reliable, and fail-safe latches between the tubular segments. The latch and a BI-STEM (Storable Tubular Extendible Member) actuator work together to eliminate the need for the segments to overlap when deployed. This yields an unusually lightweight boom and compact launch configuration. An aluminum space-flight prototype with three joints displays zero structural deadband, low hysteresis, and high damping. The development approach and difficulties are discussed. Test results provide a joint model for sizing flight booms of any diameter and length.

  3. Rigidizing Inflatable Deployable Dwelling (RIDD) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — By combining thin thermoplastic films, woven Vectran reinforcements, and heat a reliable, deployable, rigidizing space habitat can be created. Although much research...

  4. Low Mass Aeroshell Deployment Mechanism Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Cornerstone Research Group Inc. (CRG) will develop new shape memory polymer (SMP) deployment mechanisms for actuating thermal protection system (TPS) panels to...

  5. Low Mass Aeroshell Deployment Mechanism Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Cornerstone Research Group Inc. (CRG) will develop new shape memory polymer (SMP) deployment mechanisms for actuating thermal protective systems (TPS) panels to...

  6. Self-Deploying Gossamer Support Structure Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Phase I results demonstrated the feasibility of using shape memory polymer composites to deploy, tension and support gossamer antennas. Cornerstone Research Group,...

  7. A New Method of Designing Circularly Symmetric Shaped Dual Reflector Antennas Using Distorted Conics

    Directory of Open Access Journals (Sweden)

    Mohammad Asif Zaman

    2014-01-01

    Full Text Available A new method of designing circularly symmetric shaped dual reflector antennas using distorted conics is presented. The surface of the shaped subreflector is expressed using a new set of equations employing differential geometry. The proposed equations require only a small number of parameters to accurately describe practical shaped subreflector surfaces. A geometrical optics (GO based method is used to synthesize the shaped main reflector surface corresponding to the shaped subreflector. Using the proposed method, a shaped Cassegrain dual reflector system is designed. The field scattered from the subreflector is calculated using uniform geometrical theory of diffraction (UTD. Finally, a numerical example is provided showing how a shaped subreflector produces more uniform illumination over the main reflector aperture compared to an unshaped subreflector.

  8. Mercapto-based coupling agent for improved thermophotovoltaic device back surface reflector adhesion and reflectance

    Energy Technology Data Exchange (ETDEWEB)

    Wernsman, Bernard; Fiedor, Joseph N.; Irr, Lawrence G.; Palmisiano, Marc N.

    2016-10-04

    A back surface reflector (BSR) is described. The BSR includes a reflecting layer, a substrate and an adhesion layer between the reflecting layer and the substrate. The adhesion layer includes 3-mercaptopropyl (trimethoxy) silane (a.k.a. Merc).

  9. The radar cross section of non-orthogonal corner reflectors, symmetrically illuminated

    Science.gov (United States)

    Williams, J. M.

    The monostatic radar cross section of a nonorthogonal corner reflector, for symmetrical illumination, is shown to be a function of a single dimensionless group at high frequency. The function is calculated for the triangular and square trihedrals and the dihedral.

  10. Realization of LOS (Line of Sight) stabilization based on reflector using carrier attitude compensation method

    Science.gov (United States)

    Mao, Yao; Tian, Jing; Ma, Jia-guang

    2015-02-01

    The techonology of LOS stabilization is widely applicated in moving carrier photoelectric systems such as shipborne, airborne and so on. In application situations with compact structure, such as LOS stabilization system of unmanned aerial vehicle, LOS stabilization based on reflector is adopted, and the detector is installed on the carrier to reduce the volume of stabilized platform and loading weight. However, the LOS deflection angle through reflector and the rotation angle of the reflector has a ratio relation of 2:1, simple reflector of stable inertial space can not make the optical axis stable. To eliminate the limitation of mirror stabilizing method, this article puts forward the carrier attitude compensation method, which uses the inertial sensor installed on the carrier to measure the attitude change of the carrier, and the stabilized platform rotating half of the carrier turbulence angle to realize the LOS stabilization.

  11. Ultra wideband reflector antenna log-periodic feed with operating frequency range 1–20 GHz.

    Directory of Open Access Journals (Sweden)

    F. F. Dubrovka

    2010-05-01

    Full Text Available Results of modeling and optimization of electric characteristics of ultra wideband reflector antenna log-periodic feed, based on two log-periodic antennas array for operating over frequency range 1 -20 GHz, are presented.

  12. Monolithic distributed Bragg reflector cavities in Al2O3 with quality factors exceeding one million

    NARCIS (Netherlands)

    Bernhardi, Edward; van Wolferen, Hendricus A.G.M.; Worhoff, Kerstin; de Ridder, R.M.; Pollnau, Markus

    Monolithic distributed Bragg reflector (DBR) cavities with quality factors exceeding one million have been realized in aluminum oxide channel waveguides. This technology enabled the successful demonstration of the first DBR laser in this waveguide platform.

  13. High-quality distributed Bragg reflectors for resonant-cavity light-emitting diode applications

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, S.; Naranjo, F.B.; Calle, F.; Sanchez-Garcia, M.A.; Calleja, E. [ISOM, ETSI Telecomunicacion, Universidad Politecnica de Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain); Departamento de Ingenieria Electronica, ETSI Telecomunicacion, Universidad Politecnica de Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain); Vennegues, P. [CHREA-CNRS, Rue Bernard Gregory, Sophia Antipolis, 06560 Valbonne (France)

    2002-08-16

    Efficient distributed Bragg reflectors based on Al{sub x}Ga{sub 1} {sub -} {sub x}N/GaN multilayer stacks have been grown by plasma-assisted molecular-beam epitaxy on GaN/Al{sub 2}O{sub 3} templates. The final goal is to incorporate these reflectors as bottom mirrors in a backside (sapphire) resonant-cavity light-emitting diode at 510 nm. The reflectors have been characterised by atomic force microscopy, high-resolution X-ray diffraction and high-resolution transmission electron microscopy. Reflectivity measurements have also been performed, obtaining values between 30% and 50%, depending on the Al content used. The incorporation of the Al{sub x}Ga{sub 1} {sub -} {sub x}N/GaN Bragg reflector as bottom mirror in a RCLED structure improves the output power by a factor of 12 compared with conventional light-emitting diodes. (Abstract Copyright[2002], Wiley Periodicals, Inc.)

  14. Multi-beaming propertieis of reflector antennas used in radio telescopes with wide field of view

    CERN Document Server

    Iupikov, O

    2016-01-01

    The given work is devoted to the modern developments in the field of radio astronomy instrumentation. In particular, the sensitivity of the multi-beam reflector radio telescope which is fed by phased array (PAF) is considered. Using PAF as reflector feed allows obtaining wide and continuous field of view (FOV) of the telescope. This has several advantages with compare to horn-cluster feeds which are described in this work. The sensitivity inside whole FOV was computed using three different beamforming schemes.

  15. Bichromatic tuning of reflection bands in integrated CLC reflectors for optical switches, gates, and logic

    Science.gov (United States)

    Wu, Shing-Trong; Fuh, Andy Ying-Guey; Ho, Shau-Jung; Li, Ming-Shian

    2015-03-01

    This study investigates the bichromatic tuning of cholesteric liquid crystal (CLC) reflection bands from reflectors containing chiral azo dopants. Because the chiral azo molecules change their helical twist power in reversible photoisomerization, the reflection bands of the CLCs are modulated using purple and green laser beams. The CLC reflectors are integrated into an optical gate that can be used to modulate output spectra. We also apply the integrated system in optical switching and logic.

  16. Analysis, Design and Fabrication of centimeter-wave Dielectric Fresnel Zone Plate Lens and reflector

    CERN Document Server

    Mahmoudi, A; Mahmoudi, Ali; Azalzadeh, Reza

    2005-01-01

    Fresnel lens has a long history in optics. This concept at non-optical wavelengths is also applicable. In this paper we report design and fabrication of a half and quarter wave dielectric Fresnel lens made of Plexiglas, and a Fresnel reflector at 11.1 GHz frequency. We made two lenses and one reflector at same frequency and compare their gain and radiation pattern to simulated results. Some methods for better focusing action will be introduced.

  17. The optical reflector system for the CANGAROO-II imaging atmospheric Cherenkov telescope

    CERN Document Server

    Kawachi, A; Jimbo, J; Kamei, S; Kifune, T; Kubo, H; Kushida, J; Le Bohec, S; Miyawaki, K; Mori, M; Nishijima, K; Patterson, J R; Suzuki, R; Tanimori, T; Yanagita, S; Yoshikoshi, T; Yuki, A

    2001-01-01

    A new imaging atmospheric Cherenkov telescope (CANGAROO-II) with a light-weight reflector has been constructed. Light, robust, and durable mirror facets of containing CFRP (Carbon Fiber Reinforced Plastic) laminates were developed for the telescope. The attitude of each facet can be adjusted by stepping motors. In this paper, we describe the design, manufacturing, alignment procedure, and the performance of the CANGAROO-II optical reflector system.

  18. Analysis of a generalized dual reflector antenna system using physical optics

    Science.gov (United States)

    Acosta, Roberto J.; Lagin, Alan R.

    1992-01-01

    Reflector antennas are widely used in communication satellite systems because they provide high gain at low cost. Offset-fed single paraboloids and dual reflector offset Cassegrain and Gregorian antennas with multiple focal region feeds provide a simple, blockage-free means of forming multiple, shaped, and isolated beams with low sidelobes. Such antennas are applicable to communications satellite frequency reuse systems and earth stations requiring access to several satellites. While the single offset paraboloid has been the most extensively used configuration for the satellite multiple-beam antenna, the trend toward large apertures requiring minimum scanned beam degradation over the field of view 18 degrees for full earth coverage from geostationary orbit may lead to impractically long focal length and large feed arrays. Dual reflector antennas offer packaging advantages and more degrees of design freedom to improve beam scanning and cross-polarization properties. The Cassegrain and Gregorian antennas are the most commonly used dual reflector antennas. A computer program for calculating the secondary pattern and directivity of a generalized dual reflector antenna system was developed and implemented at LeRC. The theoretical foundation for this program is based on the use of physical optics methodology for describing the induced currents on the sub-reflector and main reflector. The resulting induced currents on the main reflector are integrated to obtain the antenna far-zone electric fields. The computer program is verified with other physical optics programs and with measured antenna patterns. The comparison shows good agreement in far-field sidelobe reproduction and directivity.

  19. Tilting A Small Reflector For Vernier Pointing Of A Large Antenna

    Science.gov (United States)

    Veruttipong, Watt; Bathker, Dan A.

    1995-01-01

    Simple vernier pointing technique devised to facilitate scanning beam pointing of large paraboloidal reflector so line of sight of antenna sweeps out narrow cone about fixed axis (conical scan, also known as "conscan" in art). Scan effected by one of relatively small beam-waveguide reflectors or mirrors that couple signals between antenna and distant transmitting and/or receiving electronic circuits. Easier to tilt small mirror than to tilt massive antenna structure.

  20. Experimental Validation of Plasma Metasurfaces as Tunable THz Reflectors

    Science.gov (United States)

    Colon Quinones, Roberto; Underwood, Thomas; Cappelli, Mark

    2016-10-01

    Measurements are presented which validate the use of plasma metasurfaces (PMs) as potential tunable THz reflectors. The PM considered here is an n x n array of laser produced plasma kernels generated by focusing the fundamental output from a 2 J/p Q-switched Nd:YAG laser through a multi-lens array (MLA) and into a gas of varying pressure. An M Squared Firefly-THz laser is used to generate a collimated pulse of THz light, which is then directed to the PM at varying angles of incidence. The reflected energy is measured using a Gentec-EO SDX-1187 joulemeter probe to characterize the surface impedance or reflectivity. In this presentation, we will compare the measured reflectance to values obtained from theoretical predictions and 3D finite-difference time-domain (FDTD) simulations. Work supported by the Air Force Office of Scientific Research (AFOSR). R. Colon Quinones and T. Underwood acknowledge the support of the Department of Defense (DoD) through the National Defense Science & Engineering Graduate Fellowship (NDSEG) Program.

  1. HI Survey Science with the Canadian Large Adaptive Reflector

    CERN Document Server

    Côté, S; Dewdney, P E

    2002-01-01

    The Canadian Large Adaptive Reflector (CLAR) is a proposed prototype of a new concept for large, filled-aperture radio telescopes. The prototype would have a 300-metre aperture, working up to frequencies of at least 1.4 GHz, and would be equipped with a multi-beam phased array providing a field-of-view of 0.8deg at that frequency. The largest fully-steerable radio telescope in the world, and endowed with a large field-of-view, the CLAR will be uniquely suited for deep spectral imaging over large areas of the sky. Conducted over a period of three to four years, a CLAR Northern-Sky Survey would allow us to simultaneously: survey at arcminute scales the distribution and kinematics of the faint HI in the halo of the Milky Way and High Velocity Clouds; chart the large scale distribution of galaxies in HI out to redshift close to 1; reveal the structure and dynamics of the cosmic web responsible for wide-spread Lyman $\\alpha$ absorption systems; image the signal of the reionization of the Universe over a large area...

  2. Widely Tunable Distributed Bragg Reflectors Integrated into Nanowire Waveguides.

    Science.gov (United States)

    Fu, Anthony; Gao, Hanwei; Petrov, Petar; Yang, Peidong

    2015-10-14

    Periodic structures with dimensions on the order of the wavelength of light can tailor and improve the performance of optical components, and they can enable the creation of devices with new functionalities. For example, distributed Bragg reflectors (DBRs), which are created by periodic modulations in a structure's dielectric medium, are essential in dielectric mirrors, vertical cavity surface emitting lasers, fiber Bragg gratings, and single-frequency laser diodes. This work introduces nanoscale DBRs integrated directly into gallium nitride (GaN) nanowire waveguides. Photonic band gaps that are tunable across the visible spectrum are demonstrated by precisely controlling the grating's parameters. Numerical simulations indicate that in-wire DBRs have significantly larger reflection coefficients in comparison with the nanowire's end facet. By comparing the measured spectra with the simulated spectra, the index of refraction of the GaN nanowire waveguides was extracted to facilitate the design of photonic coupling structures that are sensitive to phase-matching conditions. This work indicates the potential to design nanowire-based devices with improved performance for optical resonators and optical routing.

  3. Microtrap on a concave grating reflector for atom trapping

    Science.gov (United States)

    Zhang, Hui; Li, Tao; Yin, Ya-Ling; Li, Xing-Jia; Xia, Yong; Yin, Jian-Ping

    2016-08-01

    We propose a novel scheme of optical confinement for atoms by using a concave grating reflector. The two-dimension grating structure with a concave surface shape exhibits strong focusing ability under radially polarized illumination. Especially, the light intensity at the focal point is about 100 times higher than that of the incident light. Such a focusing optical field reflected from the curved grating structure can provide a deep potential to trap cold atoms. We discuss the feasibility of the structure serving as an optical dipole trap. Our results are as follows. (i) Van der Waals attraction potential to the surface of the structure has a low effect on trapped atoms. (ii) The maximum trapping potential is ˜ 1.14 mK in the optical trap, which is high enough to trap cold 87Rb atoms from a standard magneto-optical trap with a temperature of 120 μK, and the maximum photon scattering rate is lower than 1/s. (iii) Such a microtrap array can also manipulate and control cold molecules, or microscopic particles. Project supported by the National Natural Science Foundation of China (Grant Nos. 11374100, 91536218, and 11274114) and the Natural Science Foundation of Shanghai Municipality, China (Grant No. 13ZR1412800).

  4. Simulation of environment effects on retro-reflectors in ITER

    Energy Technology Data Exchange (ETDEWEB)

    Voitsenya, V.S.; Berezhnyj, V.L.; Konovalov, V.G.; Naidenkova, D.I.; Ryzhkov, V.I.; Solodovchenko, S.I. [NSC KIPT, Kharkov (Ukraine); Bardamid, A.F.; Vinnichenko, M.V. [Shevchenko National Univ., 03127 Kiev (Ukraine); Belyaeva, A.I. [National Technical Univ., Kharkov (Ukraine); Donne, A.J.H. [FOM-Institute for Plasma Physics Rijnhuizen (Netherlands); Gil, Ch.; Lipa, M.; Schunke, B. [Euratom-CEA, Centre d' Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Malaquais, A. [International Atomic Energy Agency (IAEA), Vienna (Austria); Topkov, A.N. [National University, Kharkov (Ukraine)

    2004-07-01

    The use of retro-reflectors (RR) is considered for 2 plasma diagnostics in ITER: -) poloidal multichannel polarimetry that is supposed to operate on a single wavelength (118 {mu}m) and -) toroidal multichannel polarimetry that will use a dual frequency CO{sub 2} laser operating at 10.6 and 9.27 {mu}m. In order to shorten the time of simulation experiments, the long term sputtering effects on optical properties of RR were studied with Cu mirrors instead of Mo mirrors, results are reported in this series of slides. It was shown that the sputtering of the top 5 {mu}m layer from a poly-crystal Mo mirror would not result in a noticeable decrease of reflectance at 118 {mu}m. For the toroidal polarimetry system with much shorter wavelengths, a similar sputtering rate is absolutely inadmissible due to much longer path length of the probing beam. It was also shown that the micro-relief that will develop on the surface of RR due to long-term sputtering, can significantly change both the reflectance and the polarization angle of the reflecting beam. Polarization angle will also be changed if the surface of RR is coated with a carbon film.

  5. Dynamic single-mode semiconductor lasers with a distributed reflector

    Energy Technology Data Exchange (ETDEWEB)

    Suematsu, Y.; Arai, S.; Kishino, K.

    1983-03-01

    Recent progress in dynamic single-mode (DSM) semiconductor lasers in the wavelength of 1.5-1.6 microns are reviewed, and the basic principle of DSM operation is given. Study of the DSM laser is originated for application to wide-band optical-fiber communication in the lowest loss wavelength region of 1.5 to 1.65 microns. A DSM laser consists of a mode-selective resonator and a transverse-mode-controller waveguide, as in the narrow-striped distributed-Bragg-reflector (DBR) laser, so as to maintain a fixed axial mode under rapid direct modulation. The technology of monolithic integration for optical circuits is applied to realize some DSM lasers. Structures, static and dynamic characteristics of lasing wavelength, output power, and reliability of state-of-the-art DSM lasers are reviewed. Dynamic spectral width of 0.3 nm, output power of a few milliwatts, and reliability over a few thousand hours are reported for experimental DSM lasers. 120 references.

  6. Dynamic single-mode semiconductor lasers with a distributed reflector

    Science.gov (United States)

    Suematsu, Y.; Arai, S.; Kishino, K.

    1983-03-01

    Recent progress in dynamic single-mode (DSM) semiconductor lasers in the wavelength of 1.5-1.6 microns are reviewed, and the basic principle of DSM operation is given. Study of the DSM laser is originated for application to wide-band optical-fiber communication in the lowest loss wavelength region of 1.5 to 1.65 microns. A DSM laser consists of a mode-selective resonator and a transverse-mode-controller waveguide, as in the narrow-striped distributed-Bragg-reflector (DBR) laser, so as to maintain a fixed axial mode under rapid direct modulation. The technology of monolithic integration for optical circuits is applied to realize some DSM lasers. Structures, static and dynamic characteristics of lasing wavelength, output power, and reliability of state-of-the-art DSM lasers are reviewed. Dynamic spectral width of 0.3 nm, output power of a few milliwatts, and reliability over a few thousand hours are reported for experimental DSM lasers.

  7. Colloidal plasmonic back reflectors for light trapping in solar cells

    Science.gov (United States)

    Mendes, Manuel J.; Morawiec, Seweryn; Simone, Francesca; Priolo, Francesco; Crupi, Isodiana

    2014-04-01

    A novel type of plasmonic light trapping structure is presented in this paper, composed of metal nanoparticles synthesized in colloidal solution and self-assembled in uniform long-range arrays using a wet-coating method. The high monodispersion in size and spherical shape of the gold colloids used in this work allows a precise match between their measured optical properties and electromagnetic simulations performed with Mie theory, and enables the full exploitation of their collective resonant plasmonic behavior for light-scattering applications. The colloidal arrays are integrated in plasmonic back reflector (PBR) structures aimed for light trapping in thin film solar cells. The PBRs exhibit high diffuse reflectance (up to 75%) in the red and near-infrared spectrum, which can pronouncedly enhance the near-bandgap photocurrent generated by the cells. Furthermore, the colloidal PBRs are fabricated by low-temperature (<120 °C) processes that allow their implementation, as a final step of the cell construction, in typical commercial thin film devices generally fabricated in a superstrate configuration.

  8. Structural-electromagnetic bidirectional coupling analysis of space large film reflector antennas

    Science.gov (United States)

    Zhang, Xinghua; Zhang, Shuxin; Cheng, ZhengAi; Duan, Baoyan; Yang, Chen; Li, Meng; Hou, Xinbin; Li, Xun

    2017-10-01

    As used for energy transmission, a space large film reflector antenna (SLFRA) is characterized by large size and enduring high power density. The structural flexibility and the microwave radiation pressure (MRP) will lead to the phenomenon of structural-electromagnetic bidirectional coupling (SEBC). In this paper, the SEBC model of SLFRA is presented, then the deformation induced by the MRP and the corresponding far field pattern deterioration are simulated. Results show that, the direction of the MRP is identical to the normal of the reflector surface, and the magnitude is proportional to the power density and the square of cosine incident angle. For a typical cosine function distributed electric field, the MRP is a square of cosine distributed across the diameter. The maximum deflections of SLFRA linearly increase with the increasing microwave power densities and the square of the reflector diameters, and vary inversely with the film thicknesses. When the reflector diameter becomes 100 m large and the microwave power density exceeds 102 W/cm2, the gain loss of the 6.3 μm-thick reflector goes beyond 0.75 dB. When the MRP-induced deflection degrades the reflector performance, the SEBC should be taken into account.

  9. Direct evidence for radar reflector originating from changes in crystal-orientation fabric

    Directory of Open Access Journals (Sweden)

    O. Eisen

    2007-06-01

    Full Text Available The origin of a strong continuous radar reflector observed with airborne radio-echo sounding (RES at the EPICA deep-drilling site in Dronning Maud Land, Antarctica, is identified as a transition in crystal fabric orientation from a vertical girdle- to increased single-pole orientation seen along the ice core. The reflector is observed with a 60 ns and 600 ns long pulse at a frequency of 150 MHz, spans one pulse length, is continuous over 5 km, and occurs at a depth of about 2020–2030 m at the drill site. Changes in conductivity as reflector origin are excluded by investigating the ice-core profile and synthetic RES data. Our observations allow to extrapolate the crystal orientation feature along the reflector in space, with implications for ice-sheet dynamics. As the conductivity profile of the EPICA shows no distinctive peak at this depths, we exclude changes in conductivity as the reflector origin. This is supported by application of numerical forward modelling of electromagnetic wave propagation, based on the conductivity profile, which is able to reproduce nearby reflections, but fails to reproduce this one. Because of background noise, the permittivity profile based on dielectric does not show prominent signals at these depths. We therefore interpret the observed reflector to originate from this change in crystal fabric.

  10. New adaptive method to optimize the secondary reflector of linear Fresnel collectors

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Guangdong

    2017-03-01

    Performance of linear Fresnel collectors may largely depend on the secondary-reflector profile design when small-aperture absorbers are used. Optimization of the secondary-reflector profile is an extremely challenging task because there is no established theory to ensure superior performance of derived profiles. In this work, an innovative optimization method is proposed to optimize the secondary-reflector profile of a generic linear Fresnel configuration. The method correctly and accurately captures impacts of both geometric and optical aspects of a linear Fresnel collector to secondary-reflector design. The proposed method is an adaptive approach that does not assume a secondary shape of any particular form, but rather, starts at a single edge point and adaptively constructs the next surface point to maximize the reflected power to be reflected to absorber(s). As a test case, the proposed optimization method is applied to an industrial linear Fresnel configuration, and the results show that the derived optimal secondary reflector is able to redirect more than 90% of the power to the absorber in a wide range of incidence angles. The proposed method can be naturally extended to other types of solar collectors as well, and it will be a valuable tool for solar-collector designs with a secondary reflector.

  11. Parametric Study of Cylindrical Dielectric Resonator Antenna (CDRA Feeder with Symmetric Parabolic Reflector

    Directory of Open Access Journals (Sweden)

    S.M. Ali

    2015-06-01

    Full Text Available In this study a parabolic reflector antenna is designed and fabricated for IEEE 802.11a WLAN application. Initially, a single element circular tuning slot coupled Cylindrical Dielectric Resonator Antenna (CDRA feeder is designed and fabricated for a symmetric parabolic reflector. Subsequently, the designed feeder is integrated at the focal point of the parabolic reflector to provide unidirectional radiation pattern with improved gain and sidelobe levels. The measured fractional impedance bandwidth achieved for the proposed antenna is 1.8% for S11<-10 dB from 5.32 to 5.52 GHz. A radiation pattern with broadside radiation and low back radiation has been obtained. A good measurement gain of approximately 13 dB is achieved over the bandwidth by placing CDRA feeder at the focal point of the parabolic reflector. In addition, a comprehensive parametric study has been conducted to realize the effect of slot size and position on the resonance frequency of the designed feeder. Furthermore, a parametric study of various reflector parameters has also been performed to study the effect of size, depth and focal point of the parabolic reflector on gain of the antenna. Important design factors have been identified from the parametric study of the antenna. The experimental and measured results show that the designed antenna is suitable for IEEE WLAN 802.11a wireless application.

  12. Scanning properties of large dual-shaped offset and symmetric reflector antennas

    Science.gov (United States)

    Galindo-Israel, Victor; Veruttipong, Watt; Norrod, Roger D.; Imbriale, William A.

    1992-01-01

    Several characteristics of dual offset (DOSR) and symmetric shaped reflectors are examined. Among these is the amelioration of the added cost of manufacturing a shaped reflector antenna, particularly a doubly curved surface for the DOSR, if adjustable panels, which may be necessary for correction of gravity and wind distortions, are also used for improving gain by shaping. The scanning properties of shaped reflectors, both offset and circularly symmetric, are examined and compared to conic section scanning characteristics. Scanning of the pencil beam is obtained by lateral and axial translation of a single point-source feed. The feed is kept pointed toward the center of the subreflector. The effects of power spillover and aperture phase error as a function of beam scanning is examined for several different types of large reflector designs including DOSR, circularly symmetric large f/D and smaller f/D dual reflector antenna systems. It is graphically illustrated that the Abbe-sine condition for improving scanning of an optical system cannot, inherently, be satisfied in a dual-shaped reflector system shaped for high gain and low feed spillover.

  13. Scanning spherical tri-reflector antenna with a moving flat mirror

    Science.gov (United States)

    Shen, Bing; Stutzman, Warren L.

    1995-03-01

    Spherical reflector systems can achieve pattern scanning without rotation of the main reflector through the use of multiple subreflectors that can move. Also, two subreflectors can be shaped to correct for spherical aberration and to control the aperture distribution on the spherical main reflector. In a previous paper we introduced a method that offers both aperture phase and intensity control and scans the main beam without an accompanying movement of the illuminated area over main reflector. The method can overcome the poor aperture utilization problem common in spherical reflector antenna systems; however, it requires motion of the entire subreflector system, including the feed, during scan. In this paper we discuss a method that does not require motion of the subreflector system during scan. This method employs a flat mirror that creates a virtual image of the subreflector system. The motion of the subreflector system in the previous design is replaced by the motion of the virtual image that is controlled by the motion of the flat mirror. The new design offers simplified mechanical motion, while maintaining beam efficiency performance comparable to that of traditional spherical tri-reflector scanning antennas, but with some sacrifice in aperture efficiency and cross-polarization performance.

  14. Porous silicon as an internal reflector in thin epitaxial solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Kuzma-Filipek, I.; Duerinckx, F.; Nieuwenhuysen, K. van; Beaucarne, G.; Poortmans, J.; Mertens, R. [IMEC vzw, Leuven (Belgium)

    2007-05-15

    Thin film epitaxial silicon solar cells are considered a near future alternative to bulk silicon solar cells. However due to the limited thickness of the active layer they require efficient light trapping. Therefore we propose the development and implementation of such light confinement by means of a porous silicon (PS) intermediate reflector at the epi/substrate interface. The formation of the reflector is done by electrochemical etching of a highly doped Si substrate into a multilayer stack (Bragg-optical reflector), and is followed by epitaxial deposition of the active layer. The implementation of the PS reflector however requires detailed analysis of many problematic issues, foremost the optical optimisation of the stack for internal reflection at the Si/PS/Si interface. Other topics include the pore rearrangement during high-temperature CVD as well as the quality of the epitaxial layer grown on porous silicon. Another challenge is the resistance within the PS layers. For that purpose, SRP (Spreading Resistance Probe) and resistance measurements were performed to determine the conductive properties of rearranged PS. First cells with a 9-layer porous silicon reflector gave a very promising efficiency of 13.5% which is 1.5% higher compared to cells without internal reflector. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Assessment of irradiation effects on beryllium reflector and heavy water tank of JRR-3M

    Energy Technology Data Exchange (ETDEWEB)

    Murayama, Yoji; Kakehuda, Kazuhiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-10-01

    The JRR-3M, a swimming pool type research reactor with beryllium and heavy water reflectors, has been operated since 1990. Since the beryllium reflectors are close to fuel and receive high fast neutron fluence in a relatively short time, they may be subject to change their dimensions by swelling due mostly to entrapped helium gaseous. This may bend the reflectors to the outside and narrow gaps between the reflectors and the fuel elements. The gaps have been measured with an ultrasonic thickness gage in an annual inspection. The results in 1996 show that the maximum of expansion in the diametral directions was 0.6 mm against 1.6 mm of a managed value for replacement of the reflector. A heavy water tank of the JRR-3M is made of aluminum alloy A5052. Surveillance tests of the alloy have been conducted to evaluate irradiation effects of the heavy water tank. Five sets of specimens of the alloy have been irradiated in the beryllium reflectors where fast neutron flux is higher than that in the heavy water tank. In 1994, one set of specimens had been unloaded and carried out the post-irradiation tests. The results show that the heavy water tank preserved satisfactory mechanical properties. (author)

  16. The Effect of Boundary Support and Reflector Dimensions on Inflatable Parabolic Antenna Performance

    Science.gov (United States)

    Coleman, Michael J.; Baginski, Frank; Romanofsky, Robert R.

    2011-01-01

    For parabolic antennas with sufficient surface accuracy, more power can be radiated with a larger aperture size. This paper explores the performance of antennas of various size and reflector depth. The particular focus is on a large inflatable elastic antenna reflector that is supported about its perimeter by a set of elastic tendons and is subjected to a constant hydrostatic pressure. The surface accuracy of the antenna is measured by an RMS calculation, while the reflector phase error component of the efficiency is determined by computing the power density at boresight. In the analysis, the calculation of antenna efficiency is not based on the Ruze Equation. Hence, no assumption regarding the distribution of the reflector surface distortions is presumed. The reflector surface is modeled as an isotropic elastic membrane using a linear stress-strain constitutive relation. Three types of antenna reflector construction are considered: one molded to an ideal parabolic form and two different flat panel design patterns. The flat panel surfaces are constructed by seaming together panels in a manner that the desired parabolic shape is approximately attained after pressurization. Numerical solutions of the model problem are calculated under a variety of conditions in order to estimate the accuracy and efficiency of these antenna systems. In the case of the flat panel constructions, several different cutting patterns are analyzed in order to determine an optimal cutting strategy.

  17. Performance Study of Thermoelectric Solar-Assisted Heat Pump with Reflectors

    Science.gov (United States)

    Lertsatitthanakorn, C.; Soponronnarit, S.; Jamradloedluk, J.; Rungsiyopas, M.; Sarachitti, R.

    2014-06-01

    The simultaneous conversion of solar radiation into thermal and electrical energy in a thermoelectric (TE) solar-assisted heat pump is, for the purposes of this study, referred to as hybrid conversion. To capture more thermal and electrical energy, flat-plate reflectors have been mounted on a TE solar collector. To obtain higher solar radiation intensity on the TE solar collector, the position of the reflectors has been changed and the optimal position of the reflectors determined by both experimental measurements and numerical calculation so as to obtain maximal concentration of solar radiation intensity. The calculated values have been found to be in good agreement with measured ones. Improvements to the thermal energy and electrical power outputs of the system can be achieved by the use of the TE solar-assisted heat pump with reflectors. For the optimum position of the reflectors, the coefficient of performance (COP) of the system formed from a TE solar collector integrated with a heat pump (TESC-HP) was 5.60. The power output and conversion efficiency of the TE modules can reach 10.09 W and 2.40%, respectively, being improved by 34.5% and 18.2%, respectively, compared with the TESC-HP without reflectors.

  18. Concurrent engineering: effective deployment strategies

    Directory of Open Access Journals (Sweden)

    Unny Menon

    1996-12-01

    Full Text Available This paper provides a comprehensive insight into current trends and developments in Concurrent Engineering for integrated development of products and processes with the goal of completing the entire cycle in a shorter time, at lower overall cost and with fewer engineering design changes after product release. The evolution and definition of Concurrent Engineering are addressed first, followed by a concise review of the following elements of the concurrent engineering approach to product development: Concept Development: The Front-End Process, identifying Customer Needs and Quality Function Deployment, Establishing Product Specifications, Concept Selection, Product Architecture, Design for Manufacturing, Effective Rapid Prototyping, and The Economics of Product Development. An outline of a computer-based tutorial developed by the authors and other graduate students funded by NASA ( accessible via the world-wide-web . is provided in this paper. A brief discussion of teamwork for successful concurrent engineering is included, t'ase histories of concurrent engineering implementation at North American and European companies are outlined with references to textbooks authored by Professor Menon and other writers. A comprehensive bibliography on concurrent engineering is included in the paper.

  19. The purely functional software deployment model

    NARCIS (Netherlands)

    Dolstra, E.

    2006-01-01

    Software deployment is the set of activities related to getting software components to work on the machines of end users. It includes activities such as installation, upgrading, uninstallation, and so on. Many tools have been developed to support deployment, but they all have serious limitations wi

  20. Self-deploying photovoltaic power system

    Science.gov (United States)

    Colozza, Anthony J. (Inventor)

    1993-01-01

    A lightweight flexible photovoltaic (PV) blanket is attached to a support structure of initially stowed telescoping members. The deployment mechanism comprises a series of extendable and rotatable columns. As these columns are extended the PV blanket is deployed to its proper configuration.

  1. Experimental thermal mechanics of deployable boom structures

    Science.gov (United States)

    Predmore, R.

    1972-01-01

    An apparatus was developed for thermal distortion measurements on deployable boom structures. The calibration procedure and thermal static bending plus twist measurements are considered. The thermal mechanics test facility is described. A table is presented for several examples of spacecraft applications of thermal static distortion measurements on 3-m deployable booms.

  2. Seismic SMHD -- Rotational Sensor Development and Deployment

    Energy Technology Data Exchange (ETDEWEB)

    Laughlin, Darren [Applied Technology Associates; Pierson, Bob [Applied Technology Associates; Brune, Bob [Consultant

    2016-06-20

    The U.S. Department of Energy (DOE) and Applied Technology Associates (ATA) are funding development and deployment of a new generation of rotational sensors for validation of rotational seismic applications. The sensors employ Magnetohydrodynamic (MHD) principles with broadband response, high dynamic range, low noise floor, proven ruggedness, and high repeatability. This paper presents current status of sensor development and deployment opportunities.

  3. Users speak out on technology deployment

    Energy Technology Data Exchange (ETDEWEB)

    Peters, Mark; Prochaska, Marty; Cromer, Paul; Zewatsky, Jennifer

    2001-02-25

    This report summarizes user feedback data collected during a recent Accelerated Site Technology Deployment (ASTD) project: the Fluor Fernald ASTD Technology Deployment Project from May, 1999 through September, 2000. The main goal of the ASTD project was to use the ''Fernald approach'' to expedite the deployment of new or innovative technologies with superior safety, cost, and/or productivity benefits to Department of Energy (DOE) facilities. The Fernald approach targets technology end-users and their managers and directly involves them with hands-on demonstrations of new or innovative technologies during technology transfer sessions. The two technologies deployed through this project were the Personal Ice Cooling System (PICS) and the oxy-gasoline torch. Participants of technology transfer sessions were requested to complete feedback surveys. Surveys evaluated the effectiveness of the Fernald approach to technology deployment and assessed the responsiveness of employees to new technologies. This report presents the results of those surveys.

  4. A Survey of IPv6 Deployment

    Directory of Open Access Journals (Sweden)

    Manal M. Alhassoun

    2016-09-01

    Full Text Available The next-generation Internet protocol (IPv6 was designed to overcome the limitation in IPv4 by using a 128-bit address instead of a 32-bit address. In addition to solving the address the limitations, IPv6 has many improved features. This research focused to survey IPv6 deployment all around the world. The objectives of this survey paper are to highlight the issues related to the IPv6 deployment and to look into the IPv4 to IPv6 transition mechanisms. Furthermore, provide insight on the global effort around the world to contribute in IPv6 deployment. In addition, identify the potential solutions or suggestions that could improve the IPv6 deployment rate. In order to achieve the said objectives we survey number of papers on IPv6 deployment from different countries and continents.

  5. Renewable Energy: Policy Considerations for Deploying Renewables

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    This information paper accompanies the IEA publication Deploying Renewables 2011: Best and Future Policy Practice (IEA, 2011a). It provides more detailed data and analysis on policies for Deploying Renewables, and is intended to complement the main publication. It provides an account of the strategic drivers underpinning renewable energy (RE) technology deployment (energy security, economic development and environment protection) and assesses RE technologies with respect to these drivers, including an estimate of GHG emissions reductions due to RE technologies. The paper also explores the different barriers to deploying renewables at a given stage of market maturity and discusses what tools policy makers can avail of to succeed in removing deployment barriers. An additional topical highlight explores the challenges associated with accelerating the diffusion of RE technologies in developing countries.

  6. Numerical simulation of deepwater deployment for offshore structures with deploying cables

    Institute of Scientific and Technical Information of China (English)

    胡小舟; 刘少军

    2015-01-01

    Deepwater deployment of offshore structures in different sea states was investigated. The whole deployment system was modeled as a lumped mass model, and discretization scheme for cable geometry and methodology for calculating the internal and external force acting on deploying cable were presented. The deployment model suitable for the time-varying length of deploying cable was specified. The free-surface flow fields together with the ship motions were used to calculate dynamic tension in the deploying cable during deployment of the structure. The deployment of deep sea mining system which was a typical subsea working system was employed. Based on lumped mass analysis model and parameters of deep sea mining system, numerical simulations were performed, and dynamic load and dynamic amplification factor (DAF) with different cable parameters, deploying velocities and sea states were obtained. It is shown that cable parameters and amplitudes of ocean waves can significantly influence the dynamic load and DAF, and the time-varying natural period of deploying system is a dominant factor, while the effect of deploying velocity is not obvious.

  7. On the Design of Radar Corner Reflectors for Deformation Monitoring in Multi-Frequency InSAR

    OpenAIRE

    Garthwaite, Matthew C.

    2017-01-01

    Trihedral corner reflectors are being increasingly used as point targets in deformation monitoring studies using interferometric synthetic aperture radar (InSAR) techniques. The frequency and size dependence of the corner reflector Radar Cross Section (RCS) means that no single design can perform equally in all the possible imaging modes and radar frequencies available on the currently orbiting Synthetic Aperture Radar (SAR) satellites. Therefore, either a corner reflector design tailored to ...

  8. Overview of Deployed EDS Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Martz, H E; Crawford, C

    2009-09-24

    The term explosive detection system (EDS) is used by the TSA to describe equipment that is certified to detect explosives in checked bags. The EDS, as certified, by the TSL must consist of device for interrogating a bag and an automated detection algorithm (ATD) for evaluating the results of the interrogation. We only consider CT as the interrogation device in this report. A schematic drawing of a CT-based EDS is shown in Figure 2. The output of the ATD is the binary decision of alarm or non-alarm. Alarms may true- or false-positives. Non-alarms may be true- or false-negatives. False positives are also denoted false alarms. The true detection means that the ATD reports an alarm when a threat is present in the scanned bag. The probability of detecting a threat given that a threat is present is denoted the probability of detection (PD). The probability of false alarm (PFA) is the case when an alarm is reported when a threat is not present in a bag. Certification in this context means passing tests for PD and PFA at the TSL. The results of the EDS include CT cross-sectional images of the bag and specifics about the alarmed objects generated by ATD. These results are presented on a display so that a person may override the decision of ATD and declare the alarm to be a non-alarm. This process is denoted clearing. Bags that are not cleared by the person are sent to a secondary inspection process. Here the bags may be opened or assessed with explosive trace detection (ETD) in order to clear the bags. Bags that are not cleared at this point are evaluated by an ordinance disposal team. The CT scanner along with ATD is denoted Level 1 screening. The process of clearing on a display is denoted Level 2 screening. Secondary inspection is denoted Level 3 screening. Vendors of the deployed EDSs supply the TSA with equipment for all three levels. Therefore, the term EDS may include the equipment provided for Levels 1, 2 and 3. A schematic diagram of an EDS and the levels of

  9. Deployable M-braced truss structure

    Science.gov (United States)

    Mikulas, M. M., Jr. (Inventor); Rhodes, M. D. (Inventor)

    1986-01-01

    A deployable M-braced truss structure, efficiently packaged into a compact stowed position and expandable to an operative position at the use site is described. The M-braced configuration effectively separates tension compression and shear in the structure and permits efficient structural design. Both diagonals and longerons telescope from an M-braced base unit and deploy either pneumatically, mechanically by springs or cables, or by powered reciprocating mechanisms. Upon full deployment, the diagonals and longerons lock into place with a simple latch mechanism.

  10. A method for producing a shaped contour radiation pattern using a single shaped reflector and a single feed

    Science.gov (United States)

    Cherrette, Alan R.; Lee, Shung-Wu; Acosta, Roberto J.

    1989-01-01

    Eliminating the corporate feed network in shaped contour beam antennas will reduce the expense, weight, and RF loss of the antenna system. One way of producing a shaped contour beam without using a feed network is to use a single shaped reflector with a single feed element. For a prescribed contour beam and feed, an optimization method for designing the reflector shape is given. As a design example, a shaped reflector is designed to produce a continental U.S. coverage (CONUS) beam. The RF performance of the shaped reflector is then verified by physical optics.

  11. LDR-qPCR法检测miRNA122a的表达及其与乳腺癌雌激素调控的关系%Ligase dependent reaction-qPCR detective method for miR-122a expression: its development and application in estrogen regulation in MCF-7 cells

    Institute of Scientific and Technical Information of China (English)

    恽文; 季明华; 李文静; 李建; 钟山亮; 唐金海; 赵建华

    2012-01-01

    目的 建立一种新的基于连接酶依赖性反应的miR-122a实时定量PCR检测方法 (LDR-qPCR);研究乳腺癌细胞MCF-7中miR-122a的表达以及雌激素水平对其的影响.方法 以乳腺癌细胞MCF-7为样本、成熟的miR-122a为检测对象,将探针的连接反应和实时荧光定量PCR技术相结合,建立LDR-qPCR法,并开展方法 学评价以及不同(有或无激素)培养环境下miR-122a的表达分析.结果 LDR-qPCR法的扩增产物特异,经测序证实为miR-122a;LDR-qPCR法重复性好(cv<10%);检测下限为5 pg/μL总RNA,比茎环RT-qPCR法(50 pg/μL)敏感10倍.miR-122a在激素饥饿的MCF-7细胞中表达上调,约为常规培养细胞的3.65倍;经5 nmol/L雌二醇处理后又出现下调(P=0.040),但未回到常规培养细胞水平.结论 LDR-qPCR法特异、灵敏,检测范围宽;乳腺癌细胞MCF-7可表达miR-122a并受雌激素水平的调节.

  12. Direct evidence for continuous radar reflector originating from changes in crystal-orientation fabric

    Directory of Open Access Journals (Sweden)

    O. Eisen

    2007-10-01

    Full Text Available The origin of a strong continuous radar reflector observed with airborne radio-echo sounding (RES at the EPICA deep-drilling site in Dronning Maud Land, Antarctica, is identified as a transition in crystal fabric orientation from a vertical girdle to an increased single-pole orientation seen along the ice core. The reflector is observed with a 60 ns and 600 ns long pulse at a frequency of 150 MHz, spans one pulse length, is continuous over 5 km, and occurs at a depth of about 2025–2045 m at the drill site. Changes in conductivity as reflector origin are excluded by investigating the ice-core profile, synthetic RES data, and a RES profile with different electromagnetic polarisation azimuths. The reflector's magnitude shows maximum values for polarisation parallel to the nearby ice divide and disappears for polarisation perpendicular to it, identifying the orientation of the girdle to lie in the vertical plane parallel to the ice divide. Observations allow us to extrapolate the crystal orientation feature along the reflector in space, with implications for ice-sheet dynamics and modeling.

  13. Neutron fluence effects on SLOWPOKE-2 beryllium reflector composition and reactivity

    Energy Technology Data Exchange (ETDEWEB)

    Puig, Francesc, E-mail: fpuig@anl.gov [Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439 (United States); Dennis, Haile, E-mail: haile.dennis02@uwimona.edu.jm [International Centre for Environmental and Nuclear Sciences, 2 Anguilla Close, University of the West Indies, Mona, Kingston 7 (Jamaica)

    2016-08-15

    Highlights: • SLOWPOKE-2 reflector composition evolution estimated using two different methods. • Reactivity effects of reflector composition changes calculated using MCNP5. • Impurities depletion dominates over poisons buildup, increasing reactivity. • Results contradict previously published behavior estimates for MNSR reactors. • Identified main factors explaining the observed prediction discrepancies. - Abstract: Within the scope of the conversion process from HEU to LEU of the Jamaican SLOWPOKE-2 reactor (JM-1), the effects of the neutron fluence on the beryllium reflector composition, and the corresponding effect on reactivity throughout the life of the reactor core, have been studied. Two different methods have been used and compared involving MCNP5, ORIGEN2.2, ORIGEN-S and COUPLE codes, reaching excellent agreement between them. The neutron flux profile and energy spectrum specific to the beryllium reflectors of this reactor design have been taken into account to analyze several scenarios, comprising both real and hypothetical conditions and involving different initial reflector compositions and reactor burnups. The analysis has been extended to provide estimates for the similar MNSR reactor design and compared with previously published predictions for the Syrian MNSR. The results show small overall reactivity effects in most cases, being dominated by impurity depletion as opposed to poison buildup, contrarily to what generally occurs in beryllium reflected reactors of far higher power and to MNSR predictions. The resulting reactivity increases are typically of less than 0.4 mk for usual impurity levels and maximum HEU core burnup achievable.

  14. A study of three techniques used in the diffraction analysis of shaped dual-reflector antennas

    Science.gov (United States)

    Cwik, Tom A.; Kildal, Per-Simon

    1989-01-01

    An examination is presented of three techniques used for the efficient computation of fields diffracted by a subreflector that has been shaped by geometrical optics synthesis. It is found that these techniques, which are based on the geometrical theory of diffraction (GTD), produce errors in the computed fields that are specific to shaped reflectors. These errors are examined for a reflector system shaped to produce maximum gain from a tapered feed illumination. The discrepancies are directly related to the caustic being located near an observation point of the GTD calculations. The errors found are localized, and they increase in magnitude as the caustic approaches the main reflector. In a general offset geometry, the location of the caustic may be located arbitrarily close to the main reflector given a prescribed output aperture distribution. For the specific case considered here-the common situation of shaping to produce maximum gain-the caustic is located near the edge of the main reflector and on the reflection shadow boundary. A local correction is derived which creates a uniform solution through the caustic and across the reflection shadow boundary. Away from this point the calculation receeds to the standard GTD solution.

  15. An investigation into shape and vibration control of space antenna reflectors

    Science.gov (United States)

    Susheel, C. K.; Kumar, Rajeev; Chauhan, Vishal S.

    2016-12-01

    A study into the shape and active vibration control of antenna reflectors, an important member of the space structures, is carried out in this paper. Geometric nonlinear analysis is considered for performance evaluation of antenna reflectors, as very high precision is an important aspect of space structures. An effort has been made to demonstrate the importance of functionally graded materials in space structures. Piezolaminated structures have been used for shape and vibration control applications for many years. However, due to the problems like debonding and delamination, the reliability of these materials in space structures is still uncertain. To overcome these problems, patches made of functionally graded piezoelectric material (FGPM) are used for shape and vibration control of antenna reflectors in this investigation. FGPM patches are also used to demonstrate the beam-shaping and beam-steering application of antenna reflectors. For the active vibration control application, a fuzzy-logic controller (FLC) is designed and validated with the experimental results. An experimental study has been conducted for comparing the performance of different controllers in the context of vibration reduction. The FLC is then used for active vibration control of an antenna reflector under the application of thermal impact and sinusoidal loading.

  16. The Abacus/Reflector and Integrated Symmetrical Concentrator: Concepts for Space Solar Power Collection and Transmission

    Science.gov (United States)

    Carrington, Connie; Fikes, John; Gerry, Mark; Perkinson, Don

    2000-01-01

    New energy sources are vital for the development of emerging nations, and the growth of industry in developed economies. Also vital is the need for these energy sources to be clean and renewable. For the past several years, NASA has been taking a new look at collecting solar energy in space and transmitting it to Earth, to planetary surfaces, and to orbiting spacecraft. Several innovative concepts are being studied for the space segment component of solar power beaming. One is the Abacus/Reflector, a large sun-oriented array structure fixed to the transmitter, and a rotating RF reflector that tracks a receiving rectenna on Earth. This concept eliminates the need for power-conducting slip rings in rotating joints between the solar collectors and the transmitter. Another concept is the Integrated Symmetrical Concentrator (ISC), composed of two very large segmented reflectors which rotate to collect and reflect the incident sunlight onto two centrally-located photovoltaic arrays. Adjacent to the PV arrays is the RF transmitter, which as a unit track the receiving rectenna, again eliminating power-conducting joints, and in addition reducing the cable lengths between the arrays and transmitter. The metering structure to maintain the position of the reflectors is a long mast, oriented perpendicular to the equatorial orbit plane. This paper presents a status of ongoing systems studies and configurations for the Abacus/Reflector and the ISC concepts, and a top-level study of packaging for launch and assembly.

  17. The upgrade of intense pulsed neutron source (IPNS) through the change of coolant and reflector

    CERN Document Server

    Baek, I C; Iverson, E B

    2002-01-01

    The current intense pulsed neutron source (IPNS) depleted uranium target is cooled by light water. The inner reflector material is graphite and the outer reflector material is beryllium. The presence of H sub 2 O in the target moderates neutrons and leads to a higher absorption loss in the target than is necessary. D sub 2 O coolant in the small quantities required minimizes this effect. We have studied the possible improvement in IPNS beam fluxes that would result from changing the coolant from H sub 2 O to D sub 2 O and the inner reflector from graphite to beryllium. Neutron intensities were calculated for directions normal to the viewed surface of each moderator for four different cases of combinations of target coolant and reflector materials. The simulations reported here were performed using the MCNPX (version 2.1.5) computer program. Our results show that substantial gains in neutron beam intensities can be achieved by appropriate combination of target coolant and reflector materials. The combination o...

  18. Stacking illumination of a confocal reflector light emitting diode automobile headlamp with an asymmetric triangular prism.

    Science.gov (United States)

    Chen, Hsi-Chao; Zhou, Jia-Hao; Zhou, Yang

    2017-02-01

    A confocal reflector lamp with an asymmetric triangular prism was designed for a stacking illumination of a light emitting diode (LED) automobile headlamp fitting ECE R112 asymmetrical regulation. The optical system includes three 1st elliptic reflectors, three 2nd parabolic reflectors, and one asymmetric triangular prism. Three elliptic and parabolic reflectors were assembled with three confocal reflector modules; two modules projected the cut-off line of a 0° angle, and the other module projected the cut-off line of a 15° angle using of an asymmetric triangular prism. The ray tracing, optical simulation, and mockup experiment results exhibited that the illumination distribution met the regulation of ECE R112 class B, and the ideal efficiency could reach 96.8% in theory. The tolerance analysis showed the efficiency remained above 98% under the error values of ±0.2  mm of the position of the LED light source, and the y direction of the up-down movement was more sensitive than the x and z directions. The measurement results of the mockup sample safety factor were all larger than 1.15 and supported the regulation of the ECE R112 Class B.

  19. The electromagnetic problem of interpanel gaps in reflector antennas

    Science.gov (United States)

    Hüschelrath, Jens

    2005-07-01

    In recent years, the performance and quality of computer simulations grew constantly, together with the availability of high-performance computers. This also affected the area of antenna simulations where the possibility to analyze complex structures using a computer model became a fundamental tool for the design process. Having the means to assess precisely the performance of an antenna available before its final construction is inevitable for a cost-effective design and operation of an antenna today. The more detailed a computer model describes the real application, the better the predictions for the real performance will be. In order to obtain the highest level of complexity and accuracy that today's computers can achieve, more and more details are added to the simulation models. Concerning this matter, the European Space Agency (ESA) became interested in assessing the degradation added to the output patterns of reflector antennas when their surfaces are constructed by single panels, exhibiting gaps between them. Up to now the surfaces of such antennas were assumed to consist of single shaped surfaces to simplify the computations. It is the scope of this study to present the applications of interest for the analysis of interpanel gaps and to propose methods for solving the problem, that can be integrated into existing simulation codes. During the study, a canonical model is derived that is capable of computing highly accurate results in short time. Simulations based on this model are performed for different gap configurations, selected using the experience from real applications. It is shown that the simple canonical model for the gaps covers a wide range of real-world applications with high accuracy, but that it also has its limits. For applications with gap-configurations that are out-of-range to apply the simple model, solutions are indicated being valid for arbitrary gap-configurations, but being also more resources-consuming. The work presented is the

  20. RadNet Air Quality (Deployable) Data

    Data.gov (United States)

    U.S. Environmental Protection Agency — RadNet Deployable Monitoring is designed to collect radiological and meteorological information and data asset needed to establish the impact of radiation levels on...

  1. Field guide to quick deployment thermocouples

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Instructions for quick deployment of thermocouples to measure fire intensity at Kulm Wetland Management District as part of the Fire Intensity Monitoring survey....

  2. Embedding Quality Function Deployment In Software Development ...

    African Journals Online (AJOL)

    2013-03-01

    Mar 1, 2013 ... product development: Marketing, Design. Engineering,. Quality ... The basic Quality Function Deployment methodology involves ... structure and planning approach, requires that more time be ..... process, and strategy. This is ...

  3. High Efficiency, Deployable Solar Cells Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Ultrathin, lightweight, flexible, and easily deployable solar cell (SC) capable of specific power greater than 1kW/kg are at an early stage of development for...

  4. Self-Deploying, Composite Habitats Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Cornerstone Research Group, Inc. (CRG), proposes to develop self-deploying, composite structures for lunar habitats, based on CRG's VeritexTM materials. These...

  5. Self-Deploying, Composite Habitats Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Cornerstone Research Group, Inc. (CRG), proposes to develop self-deploying, composite structures for lunar habitats, based on CRG's Veritex(TM) materials. These...

  6. Office of Civilian Response Deployment Tracking System

    Data.gov (United States)

    US Agency for International Development — The purpose of OCR DTS is to establish, manage and track relevant Civilian Response Corps teams for deployment by sector experience, training, education etc.

  7. Deployable structures for a human lunar base

    Science.gov (United States)

    Gruber, Petra; Häuplik, Sandra; Imhof, Barbara; Özdemir, Kürsad; Waclavicek, Rene; Perino, Maria Antoinetta

    2007-06-01

    The study Lunar exploration architecture—deployable structures for a lunar base was performed within the Alcatel Alenia Space “Lunar Exploration Architecture” study for the European Space Agency. The purpose of the study was to investigate bionic concepts applicable to deployable structures and to interpret the findings for possible implementation concepts. The study aimed at finding innovative solutions for deployment possibilities. Translating folding/unfolding principles from nature, candidate geometries were developed and researched using models, drawings and visualisations. The use of materials, joints between structural elements and construction details were investigated for these conceptual approaches. Reference scenarios were used to identify the technical and environmental conditions, which served as design drivers. Mechanical issues and the investigation of deployment processes narrowed the selection down to six chosen concepts. Their applicability was evaluated at a conceptual stage in relation to the timescale of the mission.

  8. DBAS: A Deployable Bandwidth Aggregation System

    CERN Document Server

    Habak, Karim; Harras, Khaled A

    2012-01-01

    The explosive increase in data demand coupled with the rapid deployment of various wireless access technologies have led to the increase of number of multi-homed or multi-interface enabled devices. Fully exploiting these interfaces has motivated researchers to propose numerous solutions that aggregate their available bandwidths to increase overall throughput and satisfy the end-user's growing data demand. These solutions, however, have faced a steep deployment barrier that we attempt to overcome in this paper. We propose a Deployable Bandwidth Aggregation System (DBAS) for multi-interface enabled devices. Our system does not introduce any intermediate hardware, modify current operating systems, modify socket implementations, nor require changes to current applications or legacy servers. The DBAS architecture is designed to automatically estimate the characteristics of applications and dynamically schedule various connections or packets to different interfaces. Since our main focus is deployability, we fully i...

  9. Extreme Environment Sampling System Deployment Mechanism Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Future Venus or Comet mission architectures may feature robotic sampling systems comprised of a Sampling Tool and Deployment Mechanism. Since 2005, Honeybee has been...

  10. Demonstration and Deployment Strategy Workshop: Summary

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2014-05-01

    This report is based on the proceedings of the U.S. Department of Energy Bioenergy Technologies Office Demonstration and Deployment Strategy Workshop, held on March 12–13, 2014, at Argonne National Laboratory.

  11. Spacecraft Dynamic Characteristics While Deploying Flexible Beams

    Institute of Scientific and Technical Information of China (English)

    程绪铎; 李俊峰; 樊勇; 王照林

    2002-01-01

    The attitude dynamic equations of a spacecraft while deploying two flexible beams and the beam equations were developed from momentum theory. The dynamic equations were solved numerically using the Runge-Kutta method to calculate the vibration amplitudes of the flexible beams and the attitude angular velocity. The results show that the vibration amplitudes increase as the beam length increases or as the initial attitude angular velocity increases. The results also show that the vibration amplitudes decrease as the deployment velocity increases.

  12. State perspectives on clean coal technology deployment

    Energy Technology Data Exchange (ETDEWEB)

    Moreland, T. [State of Illinois Washington Office, Washington, DC (United States)

    1997-12-31

    State governments have been funding partners in the Clean Coal Technology program since its beginnings. Today, regulatory and market uncertainties and tight budgets have reduced state investment in energy R and D, but states have developed program initiatives in support of deployment. State officials think that the federal government must continue to support these technologies in the deployment phase. Discussions of national energy policy must include attention to the Clean Coal Technology program and its accomplishments.

  13. Deploying Renewables - Best and Future Policy Practice

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-11-23

    The global energy system faces urgent challenges. Concerns about energy security are growing, as highlighted by the recent political turmoil in Northern Africa and the nuclear incident in Fukushima. At the same time, the need to respond to climate change is more critical than ever. Against this background, many governments have increased efforts to promote deployment of renewable energy -- low-carbon sources that can strengthen energy security. This has stimulated unprecedented rise in deployment, and renewables are now the fastest growing sector of the energy mix. This 'coming of age' of renewable energy also brings challenges. Growth is focused on a few of the available technologies, and rapid deployment is confined to a relatively small number of countries. In more advanced markets, managing support costs and system integration of large shares of renewable energy in a time of economic weakness and budget austerity has sparked vigorous political debate. The IEA's new report, Deploying Renewables 2011: Best and Future Policy Practice: - Provides a comprehensive review and analysis of renewable energy policy and market trends; - Analyses in detail the dynamics of deployment and provides best-practice policy principles for different stages of market maturity; - Assesses the impact and cost-effectiveness of support policies using new methodological tools and indicators; - Investigates the strategic reasons underpinning the pursuit of RE deployment by different countries and the prospects for globalisation of RE. This new book builds on and extends a 2008 IEA publication, drawing on recent policy and deployment experience world-wide. It provides guidance for policy makers and other stakeholders to avoid past mistakes, overcome new challenges and reap the benefits of deploying renewables -- today and tomorrow.

  14. Deployable radiator with flexible line loop

    Science.gov (United States)

    Keeler, Bryan V. (Inventor); Lehtinen, Arthur Mathias (Inventor); McGee, Billy W. (Inventor)

    2003-01-01

    Radiator assembly (10) for use on a spacecraft (12) is provided including at least one radiator panel assembly (26) repeatably movable between a panel stowed position (28) and a panel deployed position (36), at least two flexible lines (40) in fluid communication with the at least one radiator panel assembly (26) and repeatably movable between a stowage loop (42) and a flattened deployed loop (44).

  15. Designing Planar Deployable Objects via Scissor Structures.

    Science.gov (United States)

    Zhang, Ran; Wang, Shiwei; Chen, Xuejin; Ding, Chao; Jiang, Luo; Zhou, Jie; Liu, Ligang

    2016-02-01

    Scissor structure is used to generate deployable objects for space-saving in a variety of applications, from architecture to aerospace science. While deployment from a small, regular shape to a larger one is easy to design, we focus on a more challenging task: designing a planar scissor structure that deploys from a given source shape into a specific target shape. We propose a two-step constructive method to generate a scissor structure from a high-dimensional parameter space. Topology construction of the scissor structure is first performed to approximate the two given shapes, as well as to guarantee the deployment. Then the geometry of the scissor structure is optimized in order to minimize the connection deflections and maximize the shape approximation. With the optimized parameters, the deployment can be simulated by controlling an anchor scissor unit. Physical deployable objects are fabricated according to the designed scissor structures by using 3D printing or manual assembly. We show a number of results for different shapes to demonstrate that even with fabrication errors, our designed structures can deform fluently between the source and target shapes.

  16. 78 FR 77550 - Integrated Corridor Management Deployment Planning Grants

    Science.gov (United States)

    2013-12-23

    ... Federal Highway Administration Integrated Corridor Management Deployment Planning Grants AGENCY: Federal... is extending the application period for the Integrated Corridor Management Deployment Planning Grants... Integrated Corridor Management Deployment Planning Grants. The purpose of this notice was to invite States...

  17. Broadband Metamaterial Reflectors for Polarization Manipulation Based on Cross/Ring Resonators

    Directory of Open Access Journals (Sweden)

    Z. Zhang

    2016-09-01

    Full Text Available We presented the investigation of broadband metamaterial reflector for polarization manipulation based on cross/ring resonators. It is demonstrated that the meta¬material reflector can convert the linearly polarized inci¬dent wave to its cross polarized wave or circularly polar¬ized wave. Due to the multiple resonances at neighboring frequencies, the proposed reflector presents broadband property and high efficiency. The measured fraction band¬width of cross polarization conversion is 55.5% with effi¬ciency higher than 80%. Furthermore, a broadband circu¬lar polarizer is designed by adjusting the dimension para¬meters and the measured fraction bandwidth exceeds 30%.

  18. Electromagnetic performance analysis of reflector antennas with non-uniform errors along radius

    Institute of Scientific and Technical Information of China (English)

    Peiyuan Lian; Congsi Wang; Wei Wang; Binbin Xiang

    2016-01-01

    Based on the works of Greve and Rahmat-Sami , the electromagnetic (EM) performance of the reflector antenna with non-uniform surface errors along radius is further addressed. A mathematical model is developed to describe the weighting func-tion for the non-uniform surface errors along radius. Then, some discussions on the peak gain loss (PGL) and the first sidelobe level increase (SLLI) caused by the non-uniform surface errors are presented and several significant radiation characteristics of the reflector with non-uniform errors are pointed out. Last, based on the proposed model, the weighted root mean square (RMS) value of the surface errors is produced to evaluate the EM performance and several representative cases with different non-uniform errors are presented with good results. Results show that the weighted RMS value should be taken into account for a better quality evalu-ation of the reflector surface.

  19. GPCA vs. PCA in Recognition and 3-D Localization of Ultrasound Reflectors

    Directory of Open Access Journals (Sweden)

    Carlos A. Luna

    2010-05-01

    Full Text Available In this paper, a new method of classification and localization of reflectors, using the time-of-flight (TOF data obtained from ultrasonic transducers, is presented. The method of classification and localization is based on Generalized Principal Component Analysis (GPCA applied to the TOF values obtained from a sensor that contains four ultrasound emitters and 16 receivers. Since PCA works with vectorized representations of TOF, it does not take into account the spatial locality of receivers. The GPCA works with two-dimensional representations of TOF, taking into account information on the spatial position of the receivers. This report includes a detailed description of the method of classification and localization and the results of achieved tests with three types of reflectors in 3-D environments: planes, edges, and corners. The results in terms of processing time, classification and localization were very satisfactory for the reflectors located in the range of 50–350 cm.

  20. Discourse on the Characterization of Waveguide Distributed Bragg Reflectors for Application to Nonlinear Optics

    Science.gov (United States)

    Grieco, Andrew Lewis

    Precise characterization of waveguide parameters is necessary for the successful design of nonlinear photonic devices. This dissertation contains a description of methods for the experimental characterization of distributed Bragg reflectors for use in nonlinear optics and other applications. The general coupled-mode theory of Bragg reflection arising from a periodic dielectric perturbation is developed from Maxwell's equations. This theory is then applied to develop a method of characterizing the fundamental parameters that describe Bragg reflection by comparing the spectral response of Bragg reflector resonators. This method is also extended to characterize linear loss in waveguides. A model of nonlinear effects in Bragg reflector resonators manifesting in bistability is also developed, as this phenomenon can be detrimental to the characterization method. Specific recommendations are made regarding waveguide fabrication and experimental design to reduce sources of experimental error.

  1. Error analysis and distribution of the driving mechanism for large spherical radio telescope active reflector

    Institute of Scientific and Technical Information of China (English)

    Huang Peng; Tang Xiaoqiang; Wang Liping; Yao Rui

    2008-01-01

    In order to reduce the cost, 3-PRS mechanism is introduced into the application of supporting the active reflector unit of large radio telescope. The kinematic model of 3-PRS mechanism with rotational joint errors is derived to solve the error problem in actual engineering application. Then based on the error model, inverse and forward kinematics are analyzed. Because the solutions can not be analytically expressed, a numerical method is applied. Afterwards, the parasitic motion errors are analyzed using search method and empirical formulas of the maximum parasitic motion error are put forward. Finally, the tolerance is distributed using empirical formulas to avoid interference between adjacent reflector units. The analyses provide a theoretical basis for the design and installation of large radio telescope active reflector.

  2. Exact mesh shape design of large cable-network antenna reflectors with flexible ring truss supports

    Science.gov (United States)

    Liu, Wang; Li, Dong-Xu; Yu, Xin-Zhan; Jiang, Jian-Ping

    2014-04-01

    An exact-designed mesh shape with favorable surface accuracy is of practical significance to the performance of large cable-network antenna reflectors. In this study, a novel design approach that could guide the generation of exact spatial parabolic mesh configurations of such reflector was proposed. By incorporating the traditional force density method with the standard finite element method, this proposed approach had taken the deformation effects of flexible ring truss supports into consideration, and searched for the desired mesh shapes that can satisfy the requirement that all the free nodes are exactly located on the objective paraboloid. Compared with the conventional design method, a remarkable improvement of surface accuracy in the obtained mesh shapes had been demonstrated by numerical examples. The present work would provide a helpful technical reference for the mesh shape design of such cable-network antenna reflector in engineering practice. [Figure not available: see fulltext.

  3. Deploying process modeling and attitude control of a satellite with a large deployable antenna

    OpenAIRE

    Zhigang Xing; Gangtie Zheng

    2014-01-01

    Modeling and attitude control methods for a satellite with a large deployable antenna are studied in the present paper. Firstly, for reducing the model dimension, three dynamic models for the deploying process are developed, which are built with the methods of multi-rigid-body dynamics, hybrid coordinate and substructure. Then an attitude control method suitable for the deploying process is proposed, which can keep stability under any dynamical parameter variation. Subsequently, this attitude...

  4. Monitoring of the reflectors of ESA's Planck telescope by close-range photogrammetry

    Science.gov (United States)

    Parian, Jafar Amiri; Gruen, Armin; Cozzani, Alessandro

    2007-11-01

    The Planck mission of the European Space Agency (ESA) is designed to image the anisotropies of the Cosmic Background Radiation Field over the whole sky. Planck's objective is to analyze, with the highest accuracy ever achieved, the remnants of the radiation that filled the universe immediately after the Big Bang, which we observe today as the cosmic microwave background. To achieve this aim well-manufactured reflectors are used as parts of the Planck telescope receiving system. The system consists of the Secondary and Primary Reflectors which are sections of two different ellipsoids of revolution with diameters of 1.1 and 1.9 meters. Deformations of the reflectors which influence the optical parameters and the gain of receiving signals are investigated in vacuum and at temperatures down to 95K, using close-range photogrammetric techniques. We have designed an optimal close-range photogrammetric network by heuristic simulation for the Primary and Secondary Reflectors with a mean relative precision better than 1:1,000,000 and 1:400,000, respectively, to achieve the requested accuracies. Special considerations have been taken into account in different steps of design, such as the determinability of additional parameters under the given network configuration, datum definition, reliability and precision issues as well as workspace limits and propagating errors from different sources of errors. A least squares best-fit ellipsoid was developed to determine the optical parameters of the reflector. We present our procedure and the results of processing the photogrammetric measurements of the Flight Models of the Primary and Secondary Reflectors which were executed by Thales Alenia Space France under ESA-ESTEC contract in vacuum and at very low temperatures.

  5. Initial global 2-D shielding analysis for the Advanced Neutron Source core and reflector

    Energy Technology Data Exchange (ETDEWEB)

    Bucholz, J.A.

    1995-08-01

    This document describes the initial global 2-D shielding analyses for the Advanced Neutron Source (ANS) reactor, the D{sub 2}O reflector, the reflector vessel, and the first 200 mm of light water beyond the reflector vessel. Flux files generated here will later serve as source terms in subsequent shielding analyses. In addition to reporting fluxes and other data at key points of interest, a major objective of this report was to document how these analyses were performed, the phenomena that were included, and checks that were made to verify that these phenomena were properly modeled. In these shielding analyses, the fixed neutron source distribution in the core was based on the `lifetime-averaged` spatial power distribution. Secondary gamma production cross sections in the fuel were modified so as to account intrinsically for delayed fission gammas in the fuel as well as prompt fission gammas. In and near the fuel, this increased the low-energy gamma fluxes by 50 to 250%, but out near the reflector vessel, these same fluxes changed by only a few percent. Sensitivity studies with respect to mesh size were performed, and a new 2-D mesh distribution developed after some problems were discovered with respect to the use of numerous elongated mesh cells in the reflector. All of the shielding analyses were performed sing the ANSL-V 39n/44g coupled library with 25 thermal neutron groups in order to obtain a rigorous representation of the thermal neutron spectrum throughout the reflector. Because of upscatter in the heavy water, convergence was very slow. Ultimately, the fission cross section in the various materials had to be artificially modified in order to solve this fixed source problem as an eigenvalue problem and invoke the Vondy error-mode extrapolation technique which greatly accelerated convergence in the large 2-D RZ DORT analyses. While this was quite effective, 150 outer iterations (over energy) were still required.

  6. Initial global 2-D shielding analysis for the Advanced Neutron Source core and reflector

    Energy Technology Data Exchange (ETDEWEB)

    Bucholz, J.A.

    1995-08-01

    This document describes the initial global 2-D shielding analyses for the Advanced Neutron Source (ANS) reactor, the D{sub 2}O reflector, the reflector vessel, and the first 200 mm of light water beyond the reflector vessel. Flux files generated here will later serve as source terms in subsequent shielding analyses. In addition to reporting fluxes and other data at key points of interest, a major objective of this report was to document how these analyses were performed, the phenomena that were included, and checks that were made to verify that these phenomena were properly modeled. In these shielding analyses, the fixed neutron source distribution in the core was based on the `lifetime-averaged` spatial power distribution. Secondary gamma production cross sections in the fuel were modified so as to account intrinsically for delayed fission gammas in the fuel as well as prompt fission gammas. In and near the fuel, this increased the low-energy gamma fluxes by 50 to 250%, but out near the reflector vessel, these same fluxes changed by only a few percent. Sensitivity studies with respect to mesh size were performed, and a new 2-D mesh distribution developed after some problems were discovered with respect to the use of numerous elongated mesh cells in the reflector. All of the shielding analyses were performed sing the ANSL-V 39n/44g coupled library with 25 thermal neutron groups in order to obtain a rigorous representation of the thermal neutron spectrum throughout the reflector. Because of upscatter in the heavy water, convergence was very slow. Ultimately, the fission cross section in the various materials had to be artificially modified in order to solve this fixed source problem as an eigenvalue problem and invoke the Vondy error-mode extrapolation technique which greatly accelerated convergence in the large 2-D RZ DORT analyses. While this was quite effective, 150 outer iterations (over energy) were still required.

  7. A Management Strategy for the Heavy Water Reflector Cooling System of HANARO Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Jung, H. S.; Park, Y. C.; Lim, S. P. (and others)

    2007-11-15

    Heavy water is used as the reflector and the moderator of the HANARO research reactor. After over 10 years operation since first criticality in 1995 there arose some operational issues related with the tritium. A task force team(TFT) has been operated for 1 year since September 2006 to study and deduce resolutions of the issues concerning the tritium and the degradation of heavy water in the HANARO reflector system. The TFT drew many recommendations on the hardware upgrade, tritium containing air control, heavy water quality management, waste management, and tritium measurement system upgrade.

  8. The electric drive control system of corner reflectors of the spacecraft interferometer

    Directory of Open Access Journals (Sweden)

    Langraf Sergey

    2017-01-01

    Full Text Available This paper presents the electric drive control system of corner reflectors of the infrared Fourier transform spectrometer for meteorological satellite. Limited-swing brushless DC motor with a torsional bearing is used as a drive motor. Stringent requirements are imposed to the drive control system for stabilization of moving speed of the reflectors while obtaining the interferogram and for limitation of the reverse time. Research of influence of torsion on steady-state error of speed and ways of its compensation is conducted. The obtained results are consistent with the simulation results of the drive. It is shown that the developed drive is operable in a spacecraft system.

  9. Fast algorithm for the exact determination of the mapped effective areas of trihedral radar reflectors

    Science.gov (United States)

    Keen, K. M.

    1983-11-01

    There is currently interest in the use of trihedral radar corner reflectors as ground targets for the calibration of synthetic aperture radars and scatterometers carried by remote sensing satellites. Keen (1983) has described a new technique for the evaluation of the scattering cross-sections of radar corner reflectors. This method, which uses computer evaluation, is briefly discussed. On the basis of new experience related to the employment of the scattering cross-section prediction method, a more efficient and exact way for carrying out the evaluation of mapped effective areas has been developed. The present investigation is concerned with this alternative technique.

  10. Improvement of Axial Reflector Cross Section Generation Model for PWR Core Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Shim, Cheon Bo; Lee, Kyung Hoon; Cho, Jin Young [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    This paper covers the study for improvement of axial reflector XS generation model. In the next section, the improved 1D core model is represented in detail. Reflector XS generated by the improved model is compared to that of the conventional model in the third section. Nuclear design parameters generated by these two XS sets are also covered in that section. Significant of this study is discussed in the last section. Two-step procedure has been regarded as the most practical approach for reactor core designs because it offers core design parameters quite rapidly within acceptable range. Thus this approach is adopted for SMART (System-integrated Modular Advanced Reac- Tor) core design in KAERI with the DeCART2D1.1/ MASTER4.0 (hereafter noted as DeCART2D/ MASTER) code system. Within the framework of the two-step procedure based SMART core design, various researches have been studied to improve the core design reliability and efficiency. One of them is improvement of reflector cross section (XS) generation models. While the conventional FA/reflector two-node model used for most core designs to generate reflector XS cannot consider the actual configuration of fuel rods that intersect at right angles to axial reflectors, the revised model reflects the axial fuel configuration by introducing the radially simplified core model. The significance of the model revision is evaluated by observing HGC generated by DeCART2D, reflector XS, and core design parameters generated by adopting the two models. And it is verified that about 30 ppm CBC error can be reduced and maximum Fq error decreases from about 6 % to 2.5 % by applying the revised model. Error of AO and axial power shapes are also reduced significantly. Therefore it can be concluded that the simplified 1D core model improves the accuracy of the axial reflector XS and leads to the two-step procedure reliability enhancement. Since it is hard for core designs to be free from the two-step approach, it is necessary to find

  11. Enhanced absorption of monolayer MoS2 with resonant back reflector

    CERN Document Server

    Liu, Jiang-Tao; Li, Xiao-Jing; Liu, Nian-Hua

    2014-01-01

    By extracting the permittivity of monolayer MoS2 from experiments, the optical absorption of monolayer MoS2 prepared on top of one-dimensional photonic crystal (1DPC) or metal films is investigated theoretically. The 1DPC and metal films act as resonant back reflectors that can enhance absorption of monolayer MoS2 substantially over a broad spectral range due to the Fabry-Perot cavity effect. The absorption of monolayer MoS2 can also be tuned by varying either the distance between the monolayer MoS2 and the back reflector or the thickness of the cover layers.

  12. Hybrid Back Surface Reflector GaInAsSb Thermophotovoltaic Devices

    Science.gov (United States)

    Huang, Robin K.; Wang, Christine A.; Connors, Michael K.; Turner, George W.; Dashiell, Michael

    2004-11-01

    Back surface reflectors have the potential to improve thermophotovoltaic (TPV) device performance though the recirculation of infrared photons. The "hybrid" back-surface reflector (BSR) TPV cell approach allows one to construct BSRs for TPV devices using conventional, high efficiency, GaInAsSb-based TPV material. The design, fabrication, and measurements of hybrid BSR-TPV cells are described. The BSR was shown to provide a 4 mV improvement in open-circuit voltage under a constant short-circuit current, which is comparable to the 5 mV improvement theoretically predicted. Larger improvements in open-circuit voltage are expected in the future with materials improvements.

  13. Development of optical ground verification method for μm to sub-mm reflectors

    Science.gov (United States)

    Stockman, Y.; Thizy, C.; Lemaire, P.; Georges, M.; Mazy, E.; Mazzoli, A.; Houbrechts, Y.; Rochus, P.; Roose, S.; Doyle, D.; Ulbrich, G.

    2004-06-01

    Large reflectors and antennas for the IR to mm wavelength range are being planned for many Earth observation and astronomical space missions and for commercial communication satellites as well. Scientific observatories require large telescopes with precisely shaped reflectors for collecting the electro-magnetic radiation from faint sources. The challenging tasks of on-ground testing are to achieve the required accuracy in the measurement of the reflector shapes and antenna structures and to verify their performance under simulated space conditions (vacuum, low temperatures). Due to the specific surface characteristics of reflectors operating in these spectral regions, standard optical metrology methods employed in the visible spectrum do not provide useful measurement results. The current state-of-the-art commercial metrology systems are not able to measure these types of reflectors because they have to face the measurement of shape and waviness over relatively large areas with a large deformation dynamic range and encompassing a wide range of spatial frequencies. 3-D metrology (tactile coordinate measurement) machines are generally used during the manufacturing process. Unfortunately, these instruments cannot be used in the operational environmental conditions of the reflector. The application of standard visible wavelength interferometric methods is very limited or impossible due to the large relative surface roughnesses involved. A small number of infrared interferometers have been commercially developed over the last 10 years but their applications have also been limited due to poor dynamic range and the restricted spatial resolution of their detectors. These restrictions affect also the surface error slopes that can be captured and makes their application to surfaces manufactured using CRFP honeycomb technologies rather difficult or impossible. It has therefore been considered essential, from the viewpoint of supporting future ESA exploration missions, to

  14. Design of a monolithic tunable laser based on equivalent-chirp grating reflectors.

    Science.gov (United States)

    Dai, Yitang; Xu, Kun; Wu, Jian; Li, Yan; Hong, Xiaobin; Guo, Hongxiang; Lin, Jintong

    2010-12-01

    A Vernier-tuned distributed Bragg reflector (DBR) semiconductor laser is an effective monolithic approach for wide wavelength tunability, at the expense, however, of costly electron-beam lithography during fabrication. In this Letter, a tunable laser design with equivalent-chirp based, flat-top envelope grating reflectors is proposed that can be implemented easily by conventional two-beam interference lithography. The principle is described, and a detailed design shows uniform output power (0.08 dB variation) and excellent side-mode suppression ratio (47 dB minimum) within a wide tuning range (>32 nm) through numerical simulation.

  15. Uranium Enrichment Reduction in the Prototype Gen-IV Sodium-Cooled Fast Reactor (PGSFR with PBO Reflector

    Directory of Open Access Journals (Sweden)

    Chihyung Kim

    2016-04-01

    Full Text Available The Korean Prototype Gen-IV sodium-cooled fast reactor (PGSFR is supposed to be loaded with a relatively-costly low-enriched U fuel, while its envisaged transuranic fuels are not available for transmutation. In this work, the U-enrichment reduction by improving the neutron economy is pursued to save the fuel cost. To improve the neutron economy of the core, a new reflector material, PbO, has been introduced to replace the conventional HT9 reflector in the current PGSFR core. Two types of PbO reflectors are considered: one is the conventional pin-type and the other one is an inverted configuration. The inverted PbO reflector design is intended to maximize the PbO volume fraction in the reflector assembly. In addition, the core radial configuration is also modified to maximize the performance of the PbO reflector. For the baseline PGSFR core with several reflector options, the U enrichment requirement has been analyzed and the fuel depletion analysis is performed to derive the equilibrium cycle parameters. The linear reactivity model is used to determine the equilibrium cycle performances of the core. Impacts of the new PbO reflectors are characterized in terms of the cycle length, neutron leakage, radial power distribution, and operational fuel cost.

  16. Uranium enrichment reduction in the Prototype Gen-IV sodium-cooled fast reactor (PGSFR) with PBO reflector

    Energy Technology Data Exchange (ETDEWEB)

    Hartanto, Donny; Kim, Chi Hyung; Kim, Yong Hee [Dept. of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon (Korea, Republic of)

    2016-04-15

    The Korean Prototype Gen-IV sodium-cooled fast reactor (PGSFR) is supposed to be loaded with a relatively-costly low-enriched U fuel, while its envisaged transuranic fuels are not available for transmutation. In this work, the U-enrichment reduction by improving the neutron economy is pursued to save the fuel cost. To improve the neutron economy of the core, a new reflector material, PbO, has been introduced to replace the conventional HT9 reflector in the current PGSFR core. Two types of PbO reflectors are considered: one is the conventional pin-type and the other one is an inverted configuration. The inverted PbO reflector design is intended to maximize the PbO volume fraction in the reflector assembly. In addition, the core radial configuration is also modified to maximize the performance of the PbO reflector. For the baseline PGSFR core with several reflector options, the U enrichment requirement has been analyzed and the fuel depletion analysis is performed to derive the equilibrium cycle parameters. The linear reactivity model is used to determine the equilibrium cycle performances of the core. Impacts of the new PbO reflectors are characterized in terms of the cycle length, neutron leakage, radial power distribution, and operational fuel cost.

  17. Lightweight, Self-Deploying Foam Antenna Structures

    Science.gov (United States)

    Sokolowski, Witold; Levin, Steven; Rand, Peter

    2004-01-01

    Lightweight, deployable antennas for a variety of outer-space and terrestrial applications would be designed and fabricated according to the concept of cold hibernated elastic memory (CHEM) structures, according to a proposal. Mechanically deployable antennas now in use are heavy, complex, and unreliable, and they utilize packaging volume inefficiently. The proposed CHEM antenna structures would be simple and would deploy themselves without need for any mechanisms and, therefore, would be more reliable. The proposed CHEM antenna structures would also weigh less, could be packaged in smaller volumes, and would cost less, relative to mechanically deployable antennas. The CHEM concept was described in two prior NASA Tech Briefs articles: "Cold Hibernated Elastic Memory (CHEM) Expandable Structures" (NPO-20394), Vol. 23, No. 2 (February 1999), page 56; and "Solar Heating for Deployment of Foam Structures" (NPO-20961), Vol. 25, No. 10 (October 2001), page 36. To recapitulate from the cited prior articles: The CHEM concept is one of utilizing opencell foams of shape-memory polymers (SMPs) to make lightweight, reliable, simple, and inexpensive structures that can be alternately (1) compressed and stowed compactly or (2) expanded, then rigidified for use. A CHEM structure is fabricated at full size from a block of SMP foam in its glassy state [at a temperature below the glass-transition temperature (Tg) of the SMP]. The structure is heated to the rubbery state of the SMP (that is, to a temperature above Tg) and compacted to a small volume. After compaction, the structure is cooled to the glassy state of the SMP. The compacting force can then be released and the structure remains compact as long as the temperature is kept below Tg. Upon subsequent heating of the structure above Tg, the simultaneous elastic recovery of the foam and its shape-memory effect cause the structure to expand to its original size and shape. Once thus deployed, the structure can be rigidified by

  18. Study on differences between high contrast grating reflectors for TM and TE polarizations and their impact on VCSEL designs

    CERN Document Server

    Chung, Il-Sug

    2015-01-01

    A theoretical study of differences in broadband high-index-contrast grating (HCG) reflectors for TM and TE polarizations is presented, covering various grating parameters and properties of HCGs. It is shown that the HCG reflectors for TM polarization (TM HCG reflectors) have much thicker grating thicknesses and smaller grating periods than the TE HCG reflectors. This difference is found to originate from the different boundary conditions met for the electric field of each polarization. Due to this difference, the TM HCG reflectors have much shorter evanescent extension of HCG modes into low-refractive-index media surrounding the HCG. This enables to achieve a very short effective cavity length for VCSELs, which is essential for ultrahigh speed VCSELs and MEMS-tunable VCSELs. The obtained understandings on polarization dependences will be able to serve as important design guidelines for various HCG-based devices.

  19. Environmental issues affecting clean coal technology deployment

    Energy Technology Data Exchange (ETDEWEB)

    Miller, M.J. [Electric Power Research Inst., Palo Alto, CA (United States)

    1997-12-31

    The author outlines what he considers to be the key environmental issues affecting Clean Coal Technology (CCT) deployment both in the US and internationally. Since the international issues are difficult to characterize given different environmental drivers in various countries and regions, the primary focus of his remarks is on US deployment. However, he makes some general remarks, particularly regarding the environmental issues in developing vs. developed countries and how these issues may affect CCT deployment. Further, how environment affects deployment depends on which particular type of clean coal technology one is addressing. It is not the author`s intention to mention many specific technologies other than to use them for the purposes of example. He generally categorizes CCTs into four groups since environment is likely to affect deployment for each category somewhat differently. These four categories are: Precombustion technologies such as coal cleaning; Combustion technologies such as low NOx burners; Postcombustion technologies such as FGD systems and postcombustion NOx control; and New generation technologies such as gasification and fluidized bed combustion.

  20. Research on lightweight passive deployment mechanism for the secondary mirror in the deployable space telescope

    Science.gov (United States)

    Zhong, Peifeng; Li, Chuang; Jing, Nan; Chong, Yaqin; Ren, Guorui

    2016-10-01

    In this paper, a new type of lightweight passive deployment mechanism based on the tape spring and the shape memory alloy is presented for the secondary mirror of a deployable space telescope. In this passive deployment mechanism for the secondary mirror, the high elastic potential energy of the folded tape springs is used as driving force when the support structure is extended, and the high stiffness characteristics of the circular arc cross section of the tape spring can be used to achieve structure self-locking after deployment. Then a deployable space telescope combined with lightweight passive deployable mechanism for the secondary mirror is designed for applying to nanosatellite imaging. Furthermore, a lock-release device is designed to achieve the function of locking the folded structure and releasing on orbit by taking advantage of the phase transformation characteristics of shape memory alloy with temperature changing. Finally, the correction method for the deployment error of secondary mirror is discussed. The temperature of the tape springs is controlled respectively to make a required length change. This can achieve the purpose of adjusting the position of the secondary mirror and improve the deployment accuracy.

  1. Deployment Instabilities of Lobed-Pumpkin Balloon

    Science.gov (United States)

    Nakashino, Kyoichi

    A lobed-pumpkin balloon, currently being developed in ISAS/JAXA as well as in NASA, is a promising vehicle for long duration scientific observations in the stratosphere. Recent ground and flight experiments, however, have revealed that the balloon has deployment instabilities under certain conditions. In order to overcome the instability problems, a next generation SPB called 'tawara' type balloon has been proposed, in which an additional cylindrical part is appended to the standard lobed-pumpkin balloon. The present study investigates the deployment stability of tawara type SPB in comparison to that of standard lobed-pumpkin SPB through eigenvalue analysis on the basis of finite element methods. Our numerical results show that tawara type SPB enjoys excellent deployment performance over the standard lobed-pumpkin SPBs.

  2. Service Creation and Deployment in Converged Networks

    DEFF Research Database (Denmark)

    Soler, José

    This monograph (Early Experiences related to Service Creation & Deployment in Converged Networks) presents different experiences related to architectures and mechanisms for deployment of telephony services, understood as especial features complementing the basic voice service. The context...... for these experiences is the transition of telecommunication (telephony) networks from circuit switched based systems towards packet based ones. The text of this monograph proceeds, unaltered for the most, from the author’s PhD thesis “Framework for Deployment of Advanced Telecommunication Services in Current...... and Future Converged Networks”, carried out at the Technical University of Denmark in the period [April 2002-April 2005]. Even though the technologies presented in the text have evolved from that period until now, the presented scenarios and setups are still valid as interesting initial steps in the realm....

  3. Deploying Embodied AI into Virtual Worlds

    Science.gov (United States)

    Burden, David J. H.

    The last two years have seen the start of commercial activity within virtual worlds. Unlike computer games where Non-Player-Character avatars are common, in most virtual worlds they are the exception — and until recently in Second Life they were non-existent. However there is real commercial scope for Als in these worlds — in roles from virtual sales staff and tutors to personal assistants. Deploying an embodied AI into a virtual world offers a unique opportunity to evaluate embodied Als, and to develop them within an environment where human and computer are on almost equal terms. This paper presents an architecture being used for the deployment of chatbot driven avatars within the Second Life virtual world, looks at the challenges of deploying an AI within such a virtual world, the possible implications for the Turing Test, and identifies research directions for the future.

  4. A transparency model and its applications for simulation of reflector arrays and sound transmission (A)

    DEFF Research Database (Denmark)

    Christensen, Claus Lynge; Rindel, Jens Holger

    2006-01-01

    The paper describes a new method for simulating the frequency-dependent reflection and transmission of reflector arrays, and the frequency-dependent airborne sound insulation between rooms by means of a room acoustic computer model. The method makes use of a transparency method in the ray...

  5. Vehicle perceptibilty : reflectorized registration plates and alternative means : function, design and application.

    NARCIS (Netherlands)

    Griep, D.J. Thoenes, E. Schreuder, D.A. & Kranenburg, A.

    1970-01-01

    In November 1967 the Minister of Transport and Waterways in the Netherlands asked the Institute for Road Safety Research SWOV to examine the advisable design of reflectorized registration plates from the aspect of perceptibility. Allowance had to be made for the identification of motor vehicles.

  6. Periodic orbits for space-based reflectors in the circular restricted three-body problem

    Science.gov (United States)

    Salazar, F. J. T.; McInnes, C. R.; Winter, O. C.

    2017-05-01

    The use of space-based orbital reflectors to increase the total insolation of the Earth has been considered with potential applications in night-side illumination, electric power generation and climate engineering. Previous studies have demonstrated that families of displaced Earth-centered and artificial halo orbits may be generated using continuous propulsion, e.g. solar sails. In this work, a three-body analysis is performed by using the circular restricted three body problem, such that, the space mirror attitude reflects sunlight in the direction of Earth's center, increasing the total insolation. Using the Lindstedt-Poincaré and differential corrector methods, a family of halo orbits at artificial Sun-Earth L_2 points are found. It is shown that the third order approximation does not yield real solutions after the reflector acceleration exceeds 0.245 mm s^{-2}, i.e. the analytical expressions for the in- and out-of-plane amplitudes yield imaginary values. Thus, a larger solar reflector acceleration is required to obtain periodic orbits closer to the Earth. Derived using a two-body approach and applying the differential corrector method, a family of displaced periodic orbits close to the Earth are therefore found, with a solar reflector acceleration of 2.686 mm s^{-2}.

  7. See-through dye-sensitized solar cells: photonic reflectors for tandem and building integrated photovoltaics.

    Science.gov (United States)

    Heiniger, Leo-Philipp; O'Brien, Paul G; Soheilnia, Navid; Yang, Yang; Kherani, Nazir P; Grätzel, Michael; Ozin, Geoffrey A; Tétreault, Nicolas

    2013-10-25

    See-through dye-sensitized solar cells with 1D photonic crystal Bragg reflector photoanodes show an increase in peak external quantum efficiency of 47% while still maintaining high fill factors, resulting in an almost 40% increase in power conversion efficiency. These photoanodes are ideally suited for tandem and building integrated photovoltaics.

  8. Analytical modelling of waveguide mode launchers for matched feed reflector systems

    DEFF Research Database (Denmark)

    Palvig, Michael Forum; Breinbjerg, Olav; Meincke, Peter

    2016-01-01

    Matched feed horns aim to cancel cross polarization generated in offset reflector systems. An analytical method for predicting the mode spectrum generated by inclusions in such horns, e.g. stubs and pins, is presented. The theory is based on the reciprocity theorem with the inclusions represented...

  9. Reduction of effective terahertz focal spot size by means of nested concentric parabolic reflectors

    NARCIS (Netherlands)

    Neumann, V.A.; Laurita, N.J.; Pan, LiDong; Armitage, N.P.

    2016-01-01

    An ongoing limitation of terahertz spectroscopy is that the technique is generally limited to the study of relatively large samples of order 4 mm across due to the generally large size of the focal beam spot. We present a nested concentric parabolic reflector design which can reduce the terahertz fo

  10. Autocollimation system for measuring angular deformations with reflector designed by quaternionic method

    Science.gov (United States)

    Hoang, Phong V.; Konyakhin, Igor A.

    2017-06-01

    Autocollimators are widely used for angular measurements in instrument-making and the manufacture of elements of optical systems (wedges, prisms, plane-parallel plates) to check their shape parameters (rectilinearity, parallelism and planarity) and retrieve their optical parameters (curvature radii, measure and test their flange focusing). Autocollimator efficiency is due to the high sensitivity of the autocollimation method to minor rotations of the reflecting control element or the controlled surface itself. We consider using quaternions to optimize reflector parameters during autocollimation measurements as compared to the matrix technique. Mathematical model studies have demonstrated that the orthogonal positioning of the two basic unchanged directions of the tetrahedral reflector of the autocollimator is optimal by the criterion of reducing measurement errors where the axis of actual rotation is in a bisecting position towards them. Computer results are presented of running quaternion models that yielded conditions for diminishing measurement errors provided apriori information is available on the position of rotation axis. A practical technique is considered for synthesizing the parameters of the tetrahedral reflector that employs the newly-retrieved relationships. Following the relationships found between the angles of the tetrahedral reflector and the angles of the parameters of its initial orientation, an applied technique was developed to synthesize the control element for autocollimation measurements in case apriori information is available on the axis of actual rotation during monitoring measurements of shaft or pipeline deformation.

  11. Studies of beam expansion and distributed Bragg reflector lasers for fiber optics and optical signal processing

    Science.gov (United States)

    Garmire, E. M.

    1981-03-01

    Separate studies were performed on beam expansion and on distributed Bragg Reflector (DBR) lasers preliminary to monolithic integration on GaAs substrates. These components are proposed for use in optical signal processing, for fiber optic sources and for high brightness lasers.

  12. Wavelength Tuning in the Two-Section Distributed Bragg Reflector Laser Fabricatedby Quantum-Well Intermixing

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The two-section tunable ridge waveguide distributed Bragg reflector (DBR) lasers fabricated by strained In xGa1-xAsyP1-y The threshold current of the laser is 51mA. The tunable range of the laser is 3.2nm and the side mode suppression ratio (SMSR) is more than 38dB.

  13. Wavelength Tuning in the Two-Section Distributed Bragg Reflector Laser Fabricatedby Quantum-Well Intermixing

    Institute of Scientific and Technical Information of China (English)

    Lu Yu; Zhang Jing; Wang Wei; Zhu Hong-liang; Zhou Fan; Wang Bao-Jun; Zhang Jing-yuan; Zhao Ling-juan

    2003-01-01

    The two-section tunable ridge waveguide distributed Bragg reflector (DBR) lasers fabricated by strained InxGa1-xAsyP1-y. The threshold current of the laser is 51mA. The tunable range of the laser is 3.2nm and the side mode suppression ratio (SMSR) is more 38dB.

  14. Measurement of Aluminum Content In Reflector Materials For The PICO Dark Matter Detector

    Science.gov (United States)

    Borsodi, Haley; PICO Collaboration

    2015-04-01

    The PICO collaboration uses a bubble chamber technique to search for dark matter particles. Bubbles are registered with cameras, pressure sensors and acoustic transducers. To increase the visual contrast between bubbles and liquid, retro-reflectors are used to diffuse light from LEDs evenly throughout the inner chamber. One must, however, be careful that reflector materials not contribute radioactive background. Light nuclei, such as aluminum, can absorb alpha particles from radioactive contaminants and produce high energy neutron background in the inner volume of the chamber. Since aluminum oxides are a common reflector material and since commercial compositions are trade secrets, we had to demonstrate that the amounts of aluminum in the reflectors was small enough to allow them to be used in the chambers. After acid digesting candidate material strips, they were analyzed using Microwave Plasma Atomic Emission Spectroscopy. All of the proposed materials were found to have less than 1% Aluminum content (by mass), making them safe for use by the experiment. Indiana University South Bend.

  15. Modulated photonic-crystal structures as broadband back reflectors in thin-film solar cells

    NARCIS (Netherlands)

    Krc, J.; Zeman, M.; Luxembourg, S.L.; Topic, M.

    2009-01-01

    A concept of a modulated one-dimensional photonic-crystal (PC) structure is introduced as a back reflector for thin-film solar cells. The structure comprises two PC parts, each consisting of layers of different thicknesses. Using layers of amorphous silicon and amorphous silicon nitride a reflectanc

  16. Periodic orbits for space-based reflectors in the circular restricted three-body problem

    Science.gov (United States)

    Salazar, F. J. T.; McInnes, C. R.; Winter, O. C.

    2016-11-01

    The use of space-based orbital reflectors to increase the total insolation of the Earth has been considered with potential applications in night-side illumination, electric power generation and climate engineering. Previous studies have demonstrated that families of displaced Earth-centered and artificial halo orbits may be generated using continuous propulsion, e.g. solar sails. In this work, a three-body analysis is performed by using the circular restricted three body problem, such that, the space mirror attitude reflects sunlight in the direction of Earth's center, increasing the total insolation. Using the Lindstedt-Poincaré and differential corrector methods, a family of halo orbits at artificial Sun-Earth L_2 points are found. It is shown that the third order approximation does not yield real solutions after the reflector acceleration exceeds 0.245 mm s^{-2} , i.e. the analytical expressions for the in- and out-of-plane amplitudes yield imaginary values. Thus, a larger solar reflector acceleration is required to obtain periodic orbits closer to the Earth. Derived using a two-body approach and applying the differential corrector method, a family of displaced periodic orbits close to the Earth are therefore found, with a solar reflector acceleration of 2.686 mm s^{-2}.

  17. Modeling and optimization of white paint back reflectors for thin-film silicon solar cells

    NARCIS (Netherlands)

    Lipovšek, B.; Krč, J.; Isabella, O.; Zeman, M.; Topič, M.

    2010-01-01

    Diffusive dielectric materials such as white paint have been demonstrated as effective back reflectors in the photovoltaic technology. In this work, a one-dimensional (1D) optical modeling approach for simulation of white paint films is developed and implemented in a 1D optical simulator for thin-fi

  18. Inflection point caustic problems and solutions for high-gain dual-shaped reflectors

    Science.gov (United States)

    Galindo-Israel, Victor; Veruttipong, Thavath; Imbriale, William; Rengarajan, Sembiam

    1990-01-01

    The singular nature of the uniform geometrical theory of diffraction (UTD) subreflector scattered field at the vicinity of the main reflector edge (for a high-gain antenna design) is investigated. It is shown that the singularity in the UTD edge-diffracted and slope-diffracted fields is due to the reflection distance parameter approaching infinity in the transition functions. While the geometrical optics (GO) and UTD edge-diffracted fields exhibit singularities of the same order, the edge slope-diffracted field singularity is more significant and is substantial for greater subreflector edge tapers. The diffraction analysis of such a subreflector in the vicinity of the main reflector edge has been carried out efficiently and accurately by a stationary phase evaluation of the phi-integral, whereas the theta-integral is carried out numerically. Computational results from UTD and physical optics (PO) analysis of a 34-m ground station dual-shaped reflector confirm the analytical formulations for both circularly symmetric and offset asymmetric subreflectors. It is concluded that the proposed PO(theta)GO(phi) technique can be used to study the spillover or noise temperature characteristics of a high-gain reflector antenna efficiently and accurately.

  19. High-Quality Monolithic Distributed Bragg Reflector Cavities and Lasers in Alumina Channel Waveguides

    NARCIS (Netherlands)

    Bernhardi, Edward; van Wolferen, Hendricus A.G.M.; Worhoff, Kerstin; de Ridder, R.M.; Pollnau, Markus

    2011-01-01

    The design, fabrication, and characterization of surface relief Bragg gratings integrated with aluminum oxide ridge waveguides are reported. The grating lengths varied between 1.25 mm and 4.75 mm and were used to create various distributed Bragg reflector (DBR) cavities. The measured grating induced

  20. Sensing system with Michelson-type fiber optical interferometer based on single FBG reflector

    Institute of Scientific and Technical Information of China (English)

    Xueliang Zhang; Zhou Meng; Zhengliang Hu

    2011-01-01

    A sensing system, with Michelson-type fiber optical interferometer based on single fiber Bragg grating (FBG) as the reflector, is demonstrated. The system used a frequency-matched ring fiber optical laser as the source. The closed Michelson-type fiber optical interferometer system will be helpful in simplifying the developed interferometric sensor by replacing the double reflectors with only one FBG reflecting the double-side light. The basic sensing properties of the system are demonstrated, with a fiber optic piezoelectric ceramic transducer embedded in the arm of the interferometer simulating the sensing signal.%As a simple fiber optic component,fiber Bragg grating (FBG) has been used frequently as a sensor,filter or reflector[1-4],etc.Meanwhile,the Michelson-type fiber optical interferometric sensor has achieved a high level of development in the acoustic,electric,and magnetic field sensors because of its simple and low-cost structure as well as multiplexing advantages.The Michelsontype interferometer has been widely applied with Faraday rotating mirrors (FRMs) or polarization maintaining fiber reflectors particularly in the fiber optic hydrophone system[5,6].At present,further research is aimed at simplifying fiber optical interferometric sensors.