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Sample records for cube corner reflector

  1. 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.

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

    CERN Document Server

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

    2012-01-01

    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 ...

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Effective Reflection Area of a Cube Corner Retroreflector

    Institute of Scientific and Technical Information of China (English)

    CAI Yanmin; FANG Zujie; CHEN Gang; CHEN Gaoting

    2000-01-01

    The effective reflection area of a cube corner retroreflector is defined. It is testified for a cube corner retroreflector (CCR) that the ray reflected from a CCR is not parallel with the ray incident on the CCR undersurface. The effective reflection area of CCR is calculated when the ray incident on the CCR undersurface vertically, and the effective reflection area of a CCR is two thirds of the CCR undersurface.

  11. 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.

  12. Mueller calculus of polarization change in the cube-corner retroreflector.

    Science.gov (United States)

    Segre, Sergio E; Zanza, Vincenzo

    2003-09-01

    The optical ray properties of the cube-corner retroreflector (CCR) are first recalled. The change of polarization of the radiation due to CCR reflection is then derived by use of the Mueller matrix calculus. It is found that, in general, when the faces are not ideal reflectors, the useful cross section of the CCR consists of six zones, each of which produces a different change of polarization, i.e., it gives a different Mueller matrix. All the Mueller matrices depend on wavelength. The results are quite general and can be used directly also for partially polarized radiation.

  13. 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...

  14. Polarization properties of a metal corner-cube retroreflector

    Energy Technology Data Exchange (ETDEWEB)

    Bieg, B., E-mail: b.bieg@am.szczecin.pl

    2015-10-15

    The cube-corner retroreflector, an optical element consisting of three orthogonal mirrors, reflects incident beam in the exactly opposite direction. The change in the polarization state of the infrared beam, reflected from CCR constructed of three metal surfaces with complex reflexion coefficient, is discussed theoretically with ray tracing and the Jones matrices formalism. It is found that the final polarization state is modified according to the angle of incidence, the ray path through the retroreflector as well as the beam wavelength and its initial polarization. The main point is that under the specified conditions polarization changes could be minimized, what is essential for the CCR practical application at tokamak polarimetric systems.

  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. Optimization and improvement of FOA corner cube algorithm

    Science.gov (United States)

    McClay, Wilbert A., III; Awwal, Abdul A. S.; Burkhart, Scott C.; Candy, James V.

    2004-11-01

    Alignment of laser beams based on video images is a crucial task necessary to automate operation of the 192 beams at the National Ignition Facility (NIF). The final optics assembly (FOA) is the optical element that aligns the beam into the target chamber. This work presents an algorithm for determining the position of a corner cube alignment image in the final optics assembly. The improved algorithm was compared to the existing FOA algorithm on 900 noise-simulated images. While the existing FOA algorithm based on correlation with a synthetic template has a radial standard deviation of 1 pixel, the new algorithm based on classical matched filtering (CMF) and polynomial fit to the correlation peak improves the radial standard deviation performance to less than 0.3 pixels. In the new algorithm the templates are designed from real data stored during a year of actual operation.

  17. Optimization and Improvement of FOA Corner Cube Algorithm

    Energy Technology Data Exchange (ETDEWEB)

    McClay, W A; Awwal, A S; Burkhart, S C; Candy, J V

    2004-10-01

    Alignment of laser beams based on video images is a crucial task necessary to automate operation of the 192 beams at the National Ignition Facility (NIF). The final optics assembly (FOA) is the optical element that aligns the beam into the target chamber. This work presents an algorithm for determining the position of a corner cube alignment image in the final optics assembly. The improved algorithm was compared to the existing FOA algorithm on 900 noise-simulated images. While the existing FOA algorithm based on correlation with a synthetic template has a radial standard deviation of 1 pixel, the new algorithm based on classical matched filtering (CMF) and polynomial fit to the correlation peak improves the radial standard deviation performance to less than 0.3 pixels. In the new algorithm the templates are designed from real data stored during a year of actual operation.

  18. Centroid stabilization for laser alignment to corner cubes: designing a matched filter

    Energy Technology Data Exchange (ETDEWEB)

    Awwal, Abdul A. S.; Bliss, Erlan; Brunton, Gordon; Kamm, Victoria Miller; Leach, Richard R.; Lowe-Webb, Roger; Roberts, Randy; Wilhelmsen, Karl

    2016-11-08

    Automation of image-based alignment of National Ignition Facility high energy laser beams is providing the capability of executing multiple target shots per day. One important alignment is beam centration through the second and third harmonic generating crystals in the final optics assembly (FOA), which employs two retroreflecting corner cubes as centering references for each beam. Beam-to-beam variations and systematic beam changes over time in the FOA corner cube images can lead to a reduction in accuracy as well as increased convergence durations for the template-based position detector. A systematic approach is described that maintains FOA corner cube templates and guarantees stable position estimation.

  19. 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.

  20. Higher Accuracy Template for Corner Cube Reflected Image

    Energy Technology Data Exchange (ETDEWEB)

    Awwal, A S; Rice, K L; Leach, R R; Taha, T M

    2008-07-11

    Video images of laser beams are analyzed to determine the position of the laser beams for alignment purpose in the National Ignition Facility (NIF). Algorithms process beam images to facilitate automated laser alignment. One such beam image, known as the corner cube reflected pinhole image, exhibits wide beam quality variations that are processed by a matched-filter-based algorithm. The challenge is to design a representative template that captures these variations while at the same time assuring accurate position determination. This paper describes the development of a new analytical template to accurately estimate the center of a beam with good image quality. The templates are constructed to exploit several key recurring features observed in the beam images. When the beam image quality is low, the algorithm chooses a template that contains fewer features. The algorithm was implemented using a Xilinx Virtex II Pro FPGA implementation that provides a speedup of about 6.4 times over a baseline 3GHz Pentium 4 processor.

  1. TEST METHOD FOR SINGLE INTERIOR RIGHT ANGLE IN A CORNER CUBE PRISM

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new test method for single interior right angle in a corner cube prism is presented. Some key points and parameters are analyzed and derived. The advantage of this method is concluded by comparing with some current conventional methods.

  2. 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.

  3. 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 ...

  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. 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.

  6. Floating volumetric image formation using a dihedral corner reflector array device.

    Science.gov (United States)

    Miyazaki, Daisuke; Hirano, Noboru; Maeda, Yuki; Yamamoto, Siori; Mukai, Takaaki; Maekawa, Satoshi

    2013-01-01

    A volumetric display system using an optical imaging device consisting of numerous dihedral corner reflectors placed perpendicular to the surface of a metal plate is proposed. Image formation by the dihedral corner reflector array (DCRA) is free from distortion and focal length. In the proposed volumetric display system, a two-dimensional real image is moved by a mirror scanner to scan a three-dimensional (3D) space. Cross-sectional images of a 3D object are displayed in accordance with the position of the image plane. A volumetric image is observed as a stack of the cross-sectional images. The use of the DCRA brings compact system configuration and volumetric real image generation with very low distortion. An experimental volumetric display system including a DCRA, a galvanometer mirror, and a digital micro-mirror device was constructed to verify the proposed method. A volumetric image consisting of 1024×768×400 voxels was formed by the experimental system.

  7. Corner cube model for Microarcsec Metrology (MAM) testbed in Space Interferometer Mission (SIM)

    Science.gov (United States)

    Wang, Xu

    2005-02-01

    A corner cube model is developed to calculate the SIM internal metrology optical delay bias (with the accuracy of picometer) due to the component imperfections, such as vertex offset, coating index error, dihedral error, and gimbal offset. This physics-based and Matlab-implemented ray-trace model provides useful guidance on the flight system design, integration, and characterization. In this paper, the details of the corner cube model will be described first. Then the sub-nanometer level model validation through the MAM testbed will be presented. Finally several examples of the model application, such as the metrology delay bias minimization, design parameter error budget (or tolerance) allocation, and the metrology beam prints visualization, will be shown.

  8. Centroid stabilization in alignment of FOA corner cube: designing of a matched filter

    Science.gov (United States)

    Awwal, Abdul; Wilhelmsen, Karl; Roberts, Randy; Leach, Richard; Miller Kamm, Victoria; Ngo, Tony; Lowe-Webb, Roger

    2015-02-01

    The current automation of image-based alignment of NIF high energy laser beams is providing the capability of executing multiple target shots per day. An important aspect of performing multiple shots in a day is to reduce additional time spent aligning specific beams due to perturbations in those beam images. One such alignment is beam centration through the second and third harmonic generating crystals in the final optics assembly (FOA), which employs two retro-reflecting corner cubes to represent the beam center. The FOA houses the frequency conversion crystals for third harmonic generation as the beams enters the target chamber. Beam-to-beam variations and systematic beam changes over time in the FOA corner-cube images can lead to a reduction in accuracy as well as increased convergence durations for the template based centroid detector. This work presents a systematic approach of maintaining FOA corner cube centroid templates so that stable position estimation is applied thereby leading to fast convergence of alignment control loops. In the matched filtering approach, a template is designed based on most recent images taken in the last 60 days. The results show that new filter reduces the divergence of the position estimation of FOA images.

  9. Polarization properties of a corner-cube retroreflector with three-dimensional polarization ray-tracing calculus.

    Science.gov (United States)

    He, Wenjun; Fu, Yuegang; Zheng, Yang; Zhang, Lei; Wang, Jiake; Liu, Zhiying; Zheng, Jianping

    2013-07-01

    The output polarization states of corner cubes (for both uncoated and metal-coated surfaces) with an input beam of arbitrary polarization state and of arbitrary tilt angle to the cube have been analyzed by using the three-dimensional polarization ray-tracing matrix method. The diattenuation and retardance of the corner-cube retroreflector (CCR) for all six different ray paths are calculated, and the relationships to the tilt angle and the tilt orientation angle are shown. When the tilt angle is large, hollow metal-coated CCR is more appropriate than solid metal-coated CCR for the case that the polarization states of output beam should be controlled.

  10. A physical optics/equivalent currents model for the RCS of trihedral corner reflectors

    Science.gov (United States)

    Balanis, Constantine A.; Polycarpou, Anastasis C.

    1993-07-01

    The scattering in the interior regions of both square and triangular trihedral corner reflectors is examined. The theoretical model presented combines geometrical and physical optics (GO and PO), used to account for reflection terms, with equivalent edge currents (EEC), used to account for first-order diffractions from the edges. First-order, second-order, and third-order reflection terms are included. Calculating the first-order reflection terms involves integrating over the entire surface of the illuminated plate. Calculating the second- and third-order reflection terms, however, is much more difficult because the illuminated area is an arbitrary polygon whose shape is dependent upon the incident angles. The method for determining the area of integration is detailed. Extensive comparisons between the high-frequency model, Finite-Difference Time-Domain (FDTD) and experimental data are used for validation of the radar cross section (RCS) of both square and triangular trihedral reflectors.

  11. Large aperture cube corner interferometer with a resolution of 0.001 cm(-1).

    Science.gov (United States)

    Kauppinen, J; Horneman, V M

    1991-06-20

    The interferometer of the Fourier transform spectrometer at the University of Oulu has been modified so that the maximum instrumental resolution is better than 10(-3) cm(-1). The resolution of the previous interferometer was 4.5 x 10(-3) cm(-1). The present interferometer consists of large cube corner mirrors and a large Mylar beam splitter. Each corner mirror has been made with three flat mirrors on an adjustable supporting frame. The interferometer was already in practical use in 1985. The first spectra (H(2)O, CO(2), N(2)O, OCS) recorded on this interferometer have been presented in HANDBOOK OF INFRARED STANDARDS WITH SPECTRAL MAPS AND TRANSITION ASSIGNMENTS BETWEEN 3 AND 2600 microm, G. Guelachvili and K. Narahari Rao, Eds. (Academic, New York, 1986).

  12. Design of Wideband Printed Antenna Array in Corner Reflector with Cosecant Square-Shaped Beam Pattern

    Directory of Open Access Journals (Sweden)

    M. Milijić

    2016-11-01

    Full Text Available The paper presents a wideband printed antenna array with a cosecant square-shaped beam pattern. The array is with four symmetrical pentagonal dipoles as radiating elements operating at the second resonance. The apex of the corner reflector is at a distance λ0/2 from antenna array. Orchard Elliott’s methods and genetic algorithm are used for synthesizing the proposed antenna. A symmetrical tapered feed network of impedance transformers enables a required distribution. Simulated and measured results show that proposed antenna model has a 15 dBi gain and side lobe suppression around 20 dB in E-plane at the frequency of 10 GHz.

  13. Radar Cross Section (RCS) reduction techniques for square trihedral corner reflectors at 35 GHz: Measurements and theoretical simulations

    Science.gov (United States)

    Janssen, G. J. M.; Hulst, R. V. D.; Nennie, E.

    1988-03-01

    Radar cross section (RCS) measurements were performed at a square trihedral corner reflector to investigate RCS reduction techniques which use camouflage materials and changes in the construction. The results are compared with an RCS modeling technique. The measurement results show that a significant RCS reduction can be achieved.

  14. Fabrication of corner cube array retro-reflective structure with DLP-based 3D printing technology

    Science.gov (United States)

    Riahi, Mohammadreza

    2016-06-01

    In this article, the fabrication of a corner cube array retro-reflective structure is presented by using DLP-based 3D printing technology. In this additive manufacturing technology a pattern of a cube corner array is designed in a computer and sliced with specific software. The image of each slice is then projected from the bottom side of a reservoir, containing UV cure resin, utilizing a DLP video projector. The projected area is cured and attached to a base plate. This process is repeated until the entire part is made. The best orientation of the printing process and the effect of layer thicknesses on the surface finish of the cube has been investigated. The thermal reflow surface finishing and replication with soft molding has also been presented in this article.

  15. 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

  16. Corner reflector SAR interferometry as an element of a landslide early warning system

    Science.gov (United States)

    Singer, J.; Riedmann, M.; Lang, O.; Anderssohn, J.; Thuro, K.; Wunderlich, Th.; Heunecke, O.; Minet, Ch.

    2012-04-01

    The development of efficient and cost-effective landslide monitoring techniques is the central aim of the alpEWAS research project (www.alpewas.de). Within the scope of the project a terrestrial geosensor network on a landslide site in the Bavarian Alps has been set up, consisting of low cost GNSS with subcentimeter precision, time domain reflectometry (TDR) and video tacheometry (VTPS). To increase the spatial sampling, 16 low-cost Radar Corner Reflectors (CRs) were installed on the site in 2011. The CRs are to reflect radar signals back to the TerraSAR-X radar satellite, allowing for precise displacement measurements. The subject of this study is the application of the CR SAR Interferometry (CRInSAR) technique, and the integration of the derived motion field into an early warning system for landslide monitoring based on terrestrial measurements. An accurate validation data set is realized independently of the monitoring network using millimeter precision GNSS and tacheometer measurements. The 12 CRs from Astrium Geo-Information Services employed over the test site were specifically designed for TerraSAR-X satellite passes. They are made of concrete with integrated metal plates weighing about 80 to 100 kg. They are of triangular trihedral shape with minimal dimensions to obtain a Radar Cross Section 100 times stronger than that of the surrounding area. The concrete guarantees stability against harsh weather conditions, and robustness with respect to vandalism or theft. In addition, the Technical University of Munich (TUM) and the German Aerospace Center (DLR) installed another four CRs made entirely out of aluminum, with the TUM reflectors being of similar minimum size than the Astrium reflectors. Three CRs were placed on assumed stable ground outside the slope area and shall act as reference reflectors. Since the installation date of most CRs (25/08/2011), TerraSAR-X HighResolution SpotLight data have been repeatedly acquired from ascending orbit over the test

  17. Interferometric SAR monitoring of the Vallcebre landslide (Spain using corner reflectors

    Directory of Open Access Journals (Sweden)

    M. Crosetto

    2013-04-01

    Full Text Available This paper describes the deformation monitoring of the Vallcebre landslide (Eastern Pyrenees, Spain using the Differential Interferometric Synthetic Aperture Radar (DInSAR technique and corner reflectors (CRs. The fundamental aspects of this satellite-based deformation monitoring technique are described to provide the key elements needed to fully understand and correctly interpret its results. Several technical and logistic aspects related to the use of CRs are addressed including an analysis of the suitability of DInSAR data to monitor a specific landslide, a discussion on the choice of the type of CRs, suggestions for the installation of CRs and a description of the design of a CR network. This is followed by the description of the DInSAR data analysis procedure required to derive deformation estimates starting from the main observables of the procedure, i.e., the interferometric phases. The main observation equation is analysed, discussing the role of each phase component. A detailed discussion is devoted to the phase unwrapping problem, which has a direct impact on the deformation monitoring capability. Finally, the performance of CRs for monitoring ground displacements has been tested in the Vallcebre landslide (Eastern Pyrenees, Spain. Two different periods, which provide interesting results to monitor over time the kinematics of different parts of the considered landslide unit, are analysed and described.

  18. Interferometric SAR monitoring of the Vallcebre landslide (Spain) using corner reflectors

    Science.gov (United States)

    Crosetto, M.; Gili, J. A.; Monserrat, O.; Cuevas-González, M.; Corominas, J.; Serral, D.

    2013-04-01

    This paper describes the deformation monitoring of the Vallcebre landslide (Eastern Pyrenees, Spain) using the Differential Interferometric Synthetic Aperture Radar (DInSAR) technique and corner reflectors (CRs). The fundamental aspects of this satellite-based deformation monitoring technique are described to provide the key elements needed to fully understand and correctly interpret its results. Several technical and logistic aspects related to the use of CRs are addressed including an analysis of the suitability of DInSAR data to monitor a specific landslide, a discussion on the choice of the type of CRs, suggestions for the installation of CRs and a description of the design of a CR network. This is followed by the description of the DInSAR data analysis procedure required to derive deformation estimates starting from the main observables of the procedure, i.e., the interferometric phases. The main observation equation is analysed, discussing the role of each phase component. A detailed discussion is devoted to the phase unwrapping problem, which has a direct impact on the deformation monitoring capability. Finally, the performance of CRs for monitoring ground displacements has been tested in the Vallcebre landslide (Eastern Pyrenees, Spain). Two different periods, which provide interesting results to monitor over time the kinematics of different parts of the considered landslide unit, are analysed and described.

  19. Preliminary Neutronics Analysis of the ITER Toroidal Interferometer and Polarimeter Diagnostic Corner Cube Retroreflectors

    Energy Technology Data Exchange (ETDEWEB)

    Tresemer, K. R.

    2015-07-01

    ITER is an international project under construction in France that will demonstrate nuclear fusion at a power plant-relevant scale. The Toroidal Interferometer and Polarimeter (TIP) Diagnostic will be used to measure the plasma electron line density along 5 laser-beam chords. This line-averaged density measurement will be input to the ITER feedback-control system. The TIP is considered the primary diagnostic for these measurements, which are needed for basic ITER machine control. Therefore, system reliability & accuracy is a critical element in TIP’s design. There are two major challenges to the reliability of the TIP system. First is the survivability and performance of in-vessel optics and second is maintaining optical alignment over long optical paths and large vessel movements. Both of these issues greatly depend on minimizing the overall distortion due to neutron & gamma heating of the Corner Cube Retroreflectors (CCRs). These are small optical mirrors embedded in five first wall locations around the vacuum vessel, corresponding to certain plasma tangency radii. During the development of the design and location of these CCRs, several iterations of neutronics analyses were performed to determine and minimize the total distortion due to nuclear heating of the CCRs. The CCR corresponding to TIP Channel 2 was chosen for analysis as a good middle-road case, being an average distance from the plasma (of the five channels) and having moderate neutron shielding from its blanket shield housing. Results show that Channel 2 meets the requirements of the TIP Diagnostic, but barely. These results suggest other CCRs might be at risk of exceeding thermal deformation due to nuclear heating.

  20. Corner Reflector Mathematics

    Science.gov (United States)

    Popelka, Susan R.

    2011-01-01

    Tiny prisms in reflective road signs and safety vests have interesting geometrical properties that can be discussed at any level of high school mathematics. At the beginning of the school year, the author teaches a unit on these reflective materials in her precalculus class so that students can review and strengthen their geometry and trigonometry…

  1. Corner Reflector Mathematics

    Science.gov (United States)

    Popelka, Susan R.

    2011-01-01

    Tiny prisms in reflective road signs and safety vests have interesting geometrical properties that can be discussed at any level of high school mathematics. At the beginning of the school year, the author teaches a unit on these reflective materials in her precalculus class so that students can review and strengthen their geometry and trigonometry…

  2. 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.

  3. 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

  4. Design of a Four-Element, Hollow-Cube Corner Retroreflector for Satellites by use of a Genetic Algorithm.

    Science.gov (United States)

    Minato, A; Sugimoto, N

    1998-01-20

    A four-element retroreflector was designed for satellite laser ranging and Earth-satellite-Earth laser long-path absorption measurement of the atmosphere. The retroreflector consists of four symmetrically located corner retroreflectors. Each retroreflector element has curved mirrors and tuned dihedral angles to correct velocity aberrations. A genetic algorithm was employed to optimize dihedral angles of each element and the directions of the four elements. The optimized four-element retroreflector has high reflectance with a reasonably broad angular coverage. It is also shown that the genetic algorithm is effective for optimizing optics with many parameters.

  5. High-frequency techniques for RCS prediction of plate geometries and a physical optics/equivalent currents model for the RCS of trihedral corner reflectors

    Science.gov (United States)

    Balanis, Constantine A.; Polka, Lesley A.; Polycarpou, Anastasis C.

    1993-01-01

    Part 1 of this report continues the investigation, initiated in previous reports, of scattering from rectangular plates coated with lossy dielectrics. The hard polarization coefficients given in the last report are incorporated into a model, which includes second- and third-order diffractions, for the coated plate. Computed results from this model are examined and compared to measured data. A breakdown of the contribution of each of the higher-order terms to the total radar cross section (RCS) is given. The effectiveness of the uniform theory of diffraction (UTD) model in accounting for the coating effect is investigated by examining a Physical Optics (PO) model which incorporates the equivalent surface impedance approximation used in the UTD model. The PO, UTD, and experimental results are compared. Part 2 of this report presents a RCS model, based on PO and the Method of Equivalent Currents (MEC), for a trihedral corner reflector. PO is used to account for the reflected fields, while MEC is used for the diffracted fields. Single, double, and triple reflections and first-order diffractions are included in the model. A detailed derivation of the E(sub theta)-polarization, monostatic RCS is included. Computed results are compared with finite-difference time-domain (FDTD) results for validation. The PO/MEC model of this report compares very well with the FDTD model, and it is a much faster model in terms of computational speed.

  6. High-frequency techniques for RCS prediction of plate geometries and a physical optics/equivalent currents model for the RCS of trihedral corner reflectors, parts 1 and 2

    Science.gov (United States)

    Balanis, Constantine A.; Polka, Lesley A.; Polycarpou, Anastasis C.

    Formulations for scattering from the coated plate and the coated dihedral corner reflector are included. A coated plate model based upon the Uniform Theory of Diffraction (UTD) for impedance wedges was presented in the last report. In order to resolve inaccuracies and discontinuities in the predicted patterns using the UTD-based model, an improved model that uses more accurate diffraction coefficients is presented. A Physical Optics (PO) model for the coated dihedral corner reflector is presented as an intermediary step in developing a high-frequency model for this structure. The PO model is based upon the reflection coefficients for a metal-backed lossy material. Preliminary PO results for the dihedral corner reflector suggest that, in addition to being much faster computationally, this model may be more accurate than existing moment method (MM) models. An improved Physical Optics (PO)/Equivalent Currents model for modeling the Radar Cross Section (RCS) of both square and triangular, perfectly conducting, trihedral corner reflectors is presented. The new model uses the PO approximation at each reflection for the first- and second-order reflection terms. For the third-order reflection terms, a Geometrical Optics (GO) approximation is used for the first reflection; and PO approximations are used for the remaining reflections. The previously reported model used GO for all reflections except the terminating reflection. Using PO for most of the reflections results in a computationally slower model because many integrations must be performed numerically, but the advantage is that the predicted RCS using the new model is much more accurate. Comparisons between the two PO models, Finite-Difference Time-Domain (FDTD) and experimental data are presented for validation of the new model.

  7. 角锥棱镜谐振腔抗失谐特性及本征模式的研究%Investigation of the misalignment -resistant and eigenmode characteristics of the corner -cube resonator

    Institute of Scientific and Technical Information of China (English)

    王勇; 孙博; 任兆玉; 白晋涛; 侯瑶

    2013-01-01

    提理论研究了当全反镜为角锥棱镜,输出镜分别为平凹镜、平凸镜时,各种角锥棱镜谐振腔的抗失谐特性,建立了理论分析模型,并与以平-平镜为全反镜的相应腔型进行了对比。同时,利用Fox -Li数值迭代法,模拟计算了上述谐振腔本征振荡模式分布情况和各自的远场衍射分布情况。该理论研究工作为实验研究提供了必要的理论支持和数据参考。%The misalignment -resistant characteristics of the corner -cube resonator consisting of a corner cube used as the totally reflecting mirror and a plano-concave mirror and plano -convex mirror are studied theoretically ,respectively ,compared with those of the corresponding resonators with a flat -flat mirror used as the totally reflecting mirror .The eigen oscillation modes and the far -field diffraction characteristics of these resonator are also simulated .The research results provide a useful and comprehensive guide for the future practical operation of the laser using the corner -cube resonator .

  8. Performance of a long-wave infrared Fourier Transform imaging spectrometer using a corner-cube Michelson interferometer and an uncooled microbolometer array

    Science.gov (United States)

    Wang, Nan; Wu, Jianghui; Meng, Hemin; Gao, Jiaobo; Fan, Zhe; Zhang, Mingxuan; Li, Yu; Li, Jianjun

    2015-10-01

    Interference imaging spectroscopy is the advanced subject among the infrared remote sensing, and it has become an important technique to detect spatial information and spectral information of targets. It has the advantages of high flux, high spectral resolution and high spatial resolution that can be used for detecting more details of the spectral and spatial information. Based on a Michelson interferometer with its mirrors replaced by corner-cubes, principles of a hand-held, static, long-wave infrared Fourier Transform(FT) imaging spectrometer using an uncooled microbolometer array are introduced. Because in such FT-based spectral imager, the interferogram is acquired over the whole field of the camera while the scene of interest scans the path difference range, vignetting should be strongly limited while keep the size of the interferometer as small as possible. Interferometer size is given and interferential light path is verified through TracePro software. First results of field and laboratory measurements using the spectral imager are presented. Remotely obtained spectrums collected with this instrument and with those of high precise Michelson spectrometer are compared, and the measured values turned out to be closely corresponded. The results, in turn, verified the feasibility of the systematic working mode. The resulting system tested here provides datacubes of up to 640×480 pixels over the 7.7~13μm spectral range, this wavelength range reveals important information about scenes such as gas or landmine detection, and the instrument has a spectral resolution of about 8cm-1 that fulfils the requirement for most targeted applications. Examples of sky and buildings detection are shown.

  9. corner: Corner plots

    Science.gov (United States)

    Foreman-Mackey, Daniel

    2017-02-01

    corner uses matplotlib to visualize multidimensional samples using a scatterplot matrix. In these visualizations, each one- and two-dimensional projection of the sample is plotted to reveal covariances. corner was originally conceived to display the results of Markov Chain Monte Carlo simulations and the defaults are chosen with this application in mind but it can be used for displaying many qualitatively different samples. An earlier version of corner was known as triangle.py.

  10. Toric Cubes

    CERN Document Server

    Engström, Alexander; Sturmfels, Bernd

    2012-01-01

    A toric cube is a subset of the standard cube defined by binomial inequalities. These basic semialgebraic sets are precisely the images of standard cubes under monomial maps. We study toric cubes from the perspective of topological combinatorics. Explicit decompositions as CW-complexes are constructed. Their open cells are interiors of toric cubes and their boundaries are subcomplexes. The motivating example of a toric cube is the edge-product space in phylogenetics, and our work generalizes results known for that space.

  11. 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.

  12. 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.

  13. Cubes convexes

    CERN Document Server

    Nedjar, Sebastien; Cicchetti, Rosine; Lakhal, Lotfi; 10.3166/isi.11.6.11-31

    2010-01-01

    In various approaches, data cubes are pre-computed in order to answer efficiently OLAP queries. The notion of data cube has been declined in various ways: iceberg cubes, range cubes or differential cubes. In this paper, we introduce the concept of convex cube which captures all the tuples of a datacube satisfying a constraint combination. It can be represented in a very compact way in order to optimize both computation time and required storage space. The convex cube is not an additional structure appended to the list of cube variants but we propose it as a unifying structure that we use to characterize, in a simple, sound and homogeneous way, the other quoted types of cubes. Finally, we introduce the concept of emerging cube which captures the significant trend inversions. characterizations.

  14. Formation and liquid permeability of dense colloidal cube packings

    NARCIS (Netherlands)

    Castillo, Sonja I R; Thies-Weesie, Dominique M E; Philipse, Albert P.

    2015-01-01

    The liquid permeability of dense random packings of cubic colloids with rounded corners is studied for solid hematite cubes and hollow microporous silica cubes. The permeabilities of these two types of packings are similar, confirming that the micropores in the silica shell of the hollow cubes do

  15. Applications of Three Dimensional Extremal Length, I: Tiling of a Topological Cube

    CERN Document Server

    Hersonsky, Sa'ar

    2010-01-01

    Given a triangulation of a closed topological cube, we show that (under some technical condition) there is an essentially unique tiling of a rectangular parallelepiped by cubes, indexed by the vertices of the triangulation. Moreover, i - the combinatorics is preserved, and ii- the boundary is preserved: vertices corresponding to the cubes at the corners of the rectangular parallelepiped are at the corners of the topological cube. Also, the sizes of the cubes are obtained as a solution of a variational problem which is a discrete version of the notion of extremal length in three dimensional Euclidean space.

  16. Language Corner

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Dear Readers,It’s December once more, and time for the Language Corner annual "examination. " Questions have been taken from column exercises throughout the year. The test will give you an idea of your progress in Chinese, and also help us to see what changes could be made to improve the column. So give it a try!There will be one super prize, two first prizes, five second prizes, and ten third prizes.We appreciate your participation, and wish you success.-Ed.Please mail your answers to the following address by the end of February 2003:News Center, China Today24 Baiwanzhuang Street, Xicheng District, Beijing, China 100037

  17. 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)

  18. 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.

  19. 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.

  20. 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.

  1. Study of hollow corner retroreflectors for use in a synchronous orbit

    Science.gov (United States)

    Yoder, P. R., Jr.

    1975-01-01

    The performance of a hollow corner cube retroreflector made up of three mutually perpendicular optically flat mirrors when undergoing the thermal-mechanical strains induced by a spacecraft environment was studied. Of particular interest was a device of 200 square centimeter optical aperture used on a satellite in a synchronous orbit. It was assumed that the reflector always faces the earth. The effects of direct solar irradiance, earthshine, and albedo were considered. The results included the maximum mirror surface temperature during the orbit as well as the worst-case loss of optical performance due to thermally-induced mirror distortions. It was concluded that a device made of three suitably coated flat ULE mirrors, optically contacted to each other and supported mechanically in a nonrigid mount, would be expected to concentrate over 80 percent of the theoretical maximum energy in the central of the far field diffraction pattern. Continued development of the device through a detailed design, fabrication, and test phase was recommended.

  2. 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.

  3. Out of the Cube: Augmented Rubik's Cube

    Directory of Open Access Journals (Sweden)

    Oriel Bergig

    2011-01-01

    Full Text Available Computer gaming habits have a tendency to evolve with technology, the best being ones that immerse both our imagination and intellect. Here, we describe a new game platform, an Augmented Reality Rubik's cube. The cube acts simultaneously as both the controller and the game board. Gameplay is controlled by the cube, and game assets are rendered on top of it. Shuffling and tilting operations on the cube are mapped to game interaction. We discuss the game design decisions involved in developing a game for this platform, as well as the technological challenges in implementing it. Ultimately, we describe two games and discuss the conclusions of an informal user study based on those games.

  4. 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...

  5. Core shroud corner joints

    Science.gov (United States)

    Gilmore, Charles B.; Forsyth, David R.

    2013-09-10

    A core shroud is provided, which includes a number of planar members, a number of unitary corners, and a number of subassemblies each comprising a combination of the planar members and the unitary corners. Each unitary corner comprises a unitary extrusion including a first planar portion and a second planar portion disposed perpendicularly with respect to the first planar portion. At least one of the subassemblies comprises a plurality of the unitary corners disposed side-by-side in an alternating opposing relationship. A plurality of the subassemblies can be combined to form a quarter perimeter segment of the core shroud. Four quarter perimeter segments join together to form the core shroud.

  6. On middle cube graphs

    Directory of Open Access Journals (Sweden)

    C. Dalfo

    2015-10-01

    Full Text Available We study a family of graphs related to the $n$-cube. The middle cube graph of parameter k is the subgraph of $Q_{2k-1}$ induced by the set of vertices whose binary representation has either $k-1$ or $k$ number of ones. The middle cube graphs can be obtained from the well-known odd graphs by doubling their vertex set. Here we study some of the properties of the middle cube graphs in the light of the theory of distance-regular graphs. In particular, we completely determine their spectra (eigenvalues and their multiplicities, and associated eigenvectors.

  7. Watermarking Data Cubes

    Institute of Scientific and Technical Information of China (English)

    GUO Jie; QIU Wei-dong

    2009-01-01

    We propose a robust watermarking scheme and several extensions for digital right management of data cubes. The ownership information is hidden into a data cube by modifying a set of selected cell values. Its owner can use his private key to control all the watermarking parameters freely. Neither original data cube nor the watermark is required in watermark detection. Detailed analysis and extensive experiments are conducted for the proposed schemes in terms of watermark detectability, robustness and efficiency. Our results show that the scheme performs well in actual applications.

  8. 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.

  9. CubeSub

    Science.gov (United States)

    Slettebo, Christian; Jonsson, Lars Jonas

    2016-01-01

    This presentation introduces and discusses the development of the CubeSub submersible concept, an Autonomous Underwater Vehicle (AUV) designed around the CubeSat satellite form factor. The presented work is part of the author's MSc thesis in Aerospace Engineering at the Royal Institute of Technology, Stockholm, Sweden, and was performed during an internship at the Mission Design Division of the NASA Ames Research Center, Moffett Field, CA. Still in the early stages of its development, the CubeSub is to become a submersible test-bed for technology qualified for underwater and space environments. With the long-term goal of exploring the underwater environments in outer space, such as the alleged subsurface ocean of Jupiter's moon Europa, a number of technology and operational procedures must be developed and matured. To assist in this, the CubeSub platform is introduced as a tool to allow engineers and scientists to easily test qualified technology underwater. A CubeSat is a class of miniaturized satellite built to a standardized size. The base size is 1U (U for unit), corresponding to a 100 x 100 x 113.5 cu mm cube. A 1U CubeSat can in other words easily be held in one hand. Stacking units give larger satellite sizes such as the also commonly used 1.5U, 2U and 3U. The CubeSat standard is in itself already well established and hundreds of CubeSats have to date been launched into space. Compatible technology is readily available and the know-how exists in the space industry, all of which makes it a firm ground to stand on for the CubeSub. The rationale behind using the CubeSat form factor is to make use of this pre-existing foundation, making the CubeSub easy to develop, modular and readily available. It will thereby aid in the process of maturing the concept of a fully space qualified submersible headed for outer space. As a further clarification, the CubeSub is itself not meant for outer space, but to facilitate development of such a vessel. Along with its uses as a

  10. Apparatus for drying sugar cubes

    NARCIS (Netherlands)

    Derckx, H.A.J.; Torringa, H.M.

    1999-01-01

    Device for drying sugar cubes containing a heating apparatus for heating and dehumidifying the sugar cubes, a conditioning apparatus for cooling off and possibly further dehumidifying the sugar cubes and a conveying apparatus for conveying the sugar cubes through the heating apparatus and the condit

  11. Apparatus for drying sugar cubes

    NARCIS (Netherlands)

    Derckx, H.A.J.; Torringa, H.M.

    1999-01-01

    Device for drying sugar cubes containing a heating apparatus for heating and dehumidifying the sugar cubes, a conditioning apparatus for cooling off and possibly further dehumidifying the sugar cubes and a conveying apparatus for conveying the sugar cubes through the heating apparatus and the

  12. Apparatus for drying sugar cubes

    NARCIS (Netherlands)

    Derckx, H.A.J.; Torringa, H.M.

    1999-01-01

    Device for drying sugar cubes containing a heating apparatus for heating and dehumidifying the sugar cubes, a conditioning apparatus for cooling off and possibly further dehumidifying the sugar cubes and a conveying apparatus for conveying the sugar cubes through the heating apparatus and the condit

  13. 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...

  14. SpaceCube Mini

    Science.gov (United States)

    Lin, Michael; Petrick, David; Geist, Alessandro; Flatley, Thomas

    2012-01-01

    This version of the SpaceCube will be a full-fledged, onboard space processing system capable of 2500+ MIPS, and featuring a number of plug-andplay gigabit and standard interfaces, all in a condensed 3x3x3 form factor [less than 10 watts and less than 3 lb (approximately equal to 1.4 kg)]. The main processing engine is the Xilinx SIRF radiation- hardened-by-design Virtex-5 FX-130T field-programmable gate array (FPGA). Even as the SpaceCube 2.0 version (currently under test) is being targeted as the platform of choice for a number of the upcoming Earth Science Decadal Survey missions, GSFC has been contacted by customers who wish to see a system that incorporates key features of the version 2.0 architecture in an even smaller form factor. In order to fulfill that need, the SpaceCube Mini is being designed, and will be a very compact and low-power system. A similar flight system with this combination of small size, low power, low cost, adaptability, and extremely high processing power does not otherwise exist, and the SpaceCube Mini will be of tremendous benefit to GSFC and its partners. The SpaceCube Mini will utilize space-grade components. The primary processing engine of the Mini is the Xilinx Virtex-5 SIRF FX-130T radiation-hardened-by-design FPGA for critical flight applications in high-radiation environments. The Mini can also be equipped with a commercial Xilinx Virtex-5 FPGA with integrated PowerPCs for a low-cost, high-power computing platform for use in the relatively radiation- benign LEOs (low-Earth orbits). In either case, this version of the Space-Cube will weigh less than 3 pounds (.1.4 kg), conform to the CubeSat form-factor (10x10x10 cm), and will be low power (less than 10 watts for typical applications). The SpaceCube Mini will have a radiation-hardened Aeroflex FPGA for configuring and scrubbing the Xilinx FPGA by utilizing the onboard FLASH memory to store the configuration files. The FLASH memory will also be used for storing algorithm and

  15. BitCube: A Bottom-Up Cubing Engineering

    Science.gov (United States)

    Ferro, Alfredo; Giugno, Rosalba; Puglisi, Piera Laura; Pulvirenti, Alfredo

    Enhancing on line analytical processing through efficient cube computation plays a key role in Data Warehouse management. Hashing, grouping and mining techniques are commonly used to improve cube pre-computation. BitCube, a fast cubing method which uses bitmaps as inverted indexes for grouping, is presented. It horizontally partitions data according to the values of one dimension and for each resulting fragment it performs grouping following bottom-up criteria. BitCube allows also partial materialization based on iceberg conditions to treat large datasets for which a full cube pre-computation is too expensive. Space requirement of bitmaps is optimized by applying an adaption of the WAH compression technique. Experimental analysis, on both synthetic and real datasets, shows that BitCube outperforms previous algorithms for full cube computation and results comparable on iceberg cubing.

  16. Imaginary Cubes and Their Puzzles

    Directory of Open Access Journals (Sweden)

    Hideki Tsuiki

    2012-05-01

    Full Text Available Imaginary cubes are three dimensional objects which have square silhouette projections in three orthogonal ways just as a cube has. In this paper, we study imaginary cubes and present assembly puzzles based on them. We show that there are 16 equivalence classes of minimal convex imaginary cubes, among whose representatives are a hexagonal bipyramid imaginary cube and a triangular antiprism imaginary cube. Our main puzzle is to put three of the former and six of the latter pieces into a cube-box with an edge length of twice the size of the original cube. Solutions of this puzzle are based on remarkable properties of these two imaginary cubes, in particular, the possibility of tiling 3D Euclidean space.

  17. Corner Detection of Hand Gesture

    Directory of Open Access Journals (Sweden)

    Lili Zhang

    2012-12-01

    Full Text Available This paper studies the methods of corner detection of hand gesture, and mainly introduces the orthogonal three-direction chain code (3OT and uses it in corner detection of hand gesture. The study is discussed from four aspects: the techniques used in corner detection, the techniques of Freeman chain code, the main idea of 3OT, the process of corner detection with 3OT and the experiments on corner detectors used for hand gesture images of 26 letters in American Sign Language are described in detail. Experiment results show that the 3OT has well performance with exact corner detection rate and least false corner’s number.

  18. Ombuds' Corner: Social exclusion

    CERN Multimedia

    CERN bulletin

    2012-01-01

    In this special video edition of the Ombuds' Corner, Ombudsman Vincent Vuillemin takes a look at a social exclusion at CERN. Please note that the characters and situations appearing in this work are fictitious, and any resemblance to real persons or events is purely coincidental.

  19. Ombuds' Corner: Social exclusion

    CERN Multimedia

    Vincent Vuillemin

    2012-01-01

    In this special video edition of the Ombuds' Corner, Vincent Vuillemin takes a look at a social exclusion at CERN. Please note that the characters and situations appearing in this work are fictitious, and any resemblance to real persons or events is purely coincidental.   Contact the Ombuds Early!

  20. On manifolds with corners

    CERN Document Server

    Joyce, Dominic

    2009-01-01

    Manifolds without boundary, and manifolds with boundary, are universally known in Differential Geometry, but manifolds with corners (locally modelled on [0,\\infty)^k x R^{n-k}) have received comparatively little attention. The basic definitions in the subject are not agreed upon, there are several inequivalent definitions in use of manifolds with corners, of boundary, and of smooth map, depending on the applications in mind. We present a theory of manifolds with corners which includes a new notion of smooth map f : X --> Y. Compared to other definitions, our theory has the advantage of giving a category Man^c of manifolds with corners which is particularly well behaved as a category: it has products and direct products, boundaries behave in a functorial way, and there are simple conditions for the existence of fibre products X x_Z Y in Man^c. Our theory is tailored to future applications in Symplectic Geometry, and is part of a project to describe the geometric structure on moduli spaces of J-holomorphic curv...

  1. The Photogrammetry Cube

    Science.gov (United States)

    2008-01-01

    We can determine distances between objects and points of interest in 3-D space to a useful degree of accuracy from a set of camera images by using multiple camera views and reference targets in the camera s field of view (FOV). The core of the software processing is based on the previously developed foreign-object debris vision trajectory software (see KSC Research and Technology 2004 Annual Report, pp. 2 5). The current version of this photogrammetry software includes the ability to calculate distances between any specified point pairs, the ability to process any number of reference targets and any number of camera images, user-friendly editing features, including zoom in/out, translate, and load/unload, routines to help mark reference points with a Find function, while comparing them with the reference point database file, and a comprehensive output report in HTML format. In this system, scene reference targets are replaced by a photogrammetry cube whose exterior surface contains multiple predetermined precision 2-D targets. Precise measurement of the cube s 2-D targets during the fabrication phase eliminates the need for measuring 3-D coordinates of reference target positions in the camera's FOV, using for example a survey theodolite or a Faroarm. Placing the 2-D targets on the cube s surface required the development of precise machining methods. In response, 2-D targets were embedded into the surface of the cube and then painted black for high contrast. A 12-inch collapsible cube was developed for room-size scenes. A 3-inch, solid, stainless-steel photogrammetry cube was also fabricated for photogrammetry analysis of small objects.

  2. Ombud's Corner: holiday time!

    CERN Multimedia

    Sudeshna Datta-Cockerill

    2014-01-01

    In July and August, the Ombud’s Corner articles will be taking a holiday. They will resume in September. Meanwhile, the respect@CERN campaign continues so please keep on sending us your suggestions.   As announced in the last Bulletin, "We want these initiatives to belong to you. For this reason, we would like to ask you to suggest the messages you would like to see included in the posters. What does a “respectful workplace” mean for you? Send your suggestions to respect@cern.ch – and of course we will reward the authors with exclusively designed Respect@CERN-branded items. So, whether it's respect in relation to interpersonal interactions, noise, safety, the environment or anything else, we look forward to receiving your ideas. Do not hesitate – send that e-mail now!" As a reminder, all previous Ombud's Corners can be accessed in the Ombud's blog.

  3. 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...

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. CubeSat Launch Initiative

    Science.gov (United States)

    Higginbotham, Scott

    2016-01-01

    The National Aeronautics and Space Administration (NASA) recognizes the tremendous potential that CubeSats (very small satellites) have to inexpensively demonstrate advanced technologies, collect scientific data, and enhance student engagement in Science, Technology, Engineering, and Mathematics (STEM). The CubeSat Launch Initiative (CSLI) was created to provide launch opportunities for CubeSats developed by academic institutions, non-profit entities, and NASA centers. This presentation will provide an overview of the CSLI, its benefits, and its results.

  11. 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

  12. Formation and liquid permeability of dense colloidal cube packings

    Science.gov (United States)

    Castillo, Sonja I. R.; Thies-Weesie, Dominique M. E.; Philipse, Albert P.

    2015-02-01

    The liquid permeability of dense random packings of cubic colloids with rounded corners is studied for solid hematite cubes and hollow microporous silica cubes. The permeabilities of these two types of packings are similar, confirming that the micropores in the silica shell of the hollow cubes do not contribute to the permeability. From the Brinkman screening length √{k } of ˜16 nm, we infer that the relevant pores are indeed intercube pores. Furthermore, we relate the permeability to the volume fraction and specific solid volume of the cubes using the Kozeny-Carman relation. The Kozeny-Carman relation contains a constant that accounts for the topology and size distribution of the pores in the medium. The constant obtained from our study with aspherical particles is of the same order of magnitude as those from studies with spherical and ellipsoidal particles, which supports the notion that the Kozeny-Carman relation is applicable for any dense particle packing with (statistically) isotropic microstructures, irrespective of the particle shape.

  13. The Silicon Cube detector

    Energy Technology Data Exchange (ETDEWEB)

    Matea, I.; Adimi, N. [Centre d' Etudes Nucleaires de Bordeaux Gradignan - Universite Bordeaux 1 - UMR 5797, CNRS/IN2P3, Chemin du Solarium, BP 120, F-33175 Gradignan Cedex (France); Blank, B. [Centre d' Etudes Nucleaires de Bordeaux Gradignan - Universite Bordeaux 1 - UMR 5797, CNRS/IN2P3, Chemin du Solarium, BP 120, F-33175 Gradignan Cedex (France)], E-mail: blank@cenbg.in2p3.fr; Canchel, G.; Giovinazzo, J. [Centre d' Etudes Nucleaires de Bordeaux Gradignan - Universite Bordeaux 1 - UMR 5797, CNRS/IN2P3, Chemin du Solarium, BP 120, F-33175 Gradignan Cedex (France); Borge, M.J.G.; Dominguez-Reyes, R.; Tengblad, O. [Insto. Estructura de la Materia, CSIC, Serrano 113bis, E-28006 Madrid (Spain); Thomas, J.-C. [GANIL, CEA/DSM - CNRS/IN2P3, BP 55027, F-14076 Caen Cedex 5 (France)

    2009-08-21

    A new experimental device, the Silicon Cube detector, consisting of six double-sided silicon strip detectors placed in a compact geometry was developed at CENBG. Having a very good angular coverage and high granularity, it allows simultaneous measurements of energy and angular distributions of charged particles emitted from unbound nuclear states. In addition, large-volume Germanium detectors can be placed close to the collection point of the radioactive species to be studied. The setup is ideally suited for isotope separation on-line (ISOL)-type experiments to study multi-particle emitters and was tested during an experiment at the low-energy beam line of SPIRAL at GANIL.

  14. A multifunctional solar panel antenna for cube satellites

    Science.gov (United States)

    Fawole, Olutosin C.

    The basic cube satellite (CubeSat) is a modern small satellite that has a standard size of about one liter (the 1U CubeSat). Three 1U CubeSats could be stacked to form a 3U CubeSat. Their low-cost, short development time, and ease of deployment make CubeSats popular for space research, geographical information gathering, and communication applications. An antenna is a key part of the CubeSat communication subsystem. Traditionally, antennas used on CubeSats are wrapped-up wire dipole antennas, which are deployed after satellite launch. Another antenna type used on CubeSats is the patch antenna. In addition to their low gain and efficiency, deployable dipole antennas may also fail to deploy on satellite launch. On the other hand, a solid patch antenna will compete for space with solar cells when placed on a CubeSat face, interfering with satellite power generation. Slot antennas are promising alternatives to dipole and patch antennas on CubeSats. When excited, a thin slot aperture etched on a conductive sheet (ground plane) is an efficient bidirectional radiator. This open slot antenna can be backed by a reflector or cavity for unidirectional radiation, and solar cells can be placed in spaces on the ground plane not occupied by the slot. The large surface areas of 3U CubeSats can be exploited for a multifunctional antenna by integrating multiple thin slot radiators, which are backed by a thin cavity on the CubeSat surfaces. Solar cells can then be integrated on the antenna surface. Polarization diversity and frequency diversity improve the overall performance of a communication system. Having a single radiating structure that could provide these diversities is desired. It has been demonstrated that when a probe excites a square cavity with two unequal length crossed-slots, the differential radiation from the two slots combines in the far-field to yield circular polarization. In addition, it has been shown that two equal-length proximal slots, when both fed with a

  15. 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.

  16. spectral-cube: Read and analyze astrophysical spectral data cubes

    Science.gov (United States)

    Robitaille, Thomas; Ginsburg, Adam; Beaumont, Chris; Leroy, Adam; Rosolowsky, Erik

    2016-09-01

    Spectral-cube provides an easy way to read, manipulate, analyze, and write data cubes with two positional dimensions and one spectral dimension, optionally with Stokes parameters. It is a versatile data container for building custom analysis routines. It provides a uniform interface to spectral cubes, robust to the wide range of conventions of axis order, spatial projections, and spectral units that exist in the wild, and allows easy extraction of cube sub-regions using physical coordinates. It has the ability to create, combine, and apply masks to datasets and is designed to work with datasets too large to load into memory, and provide basic summary statistic methods like moments and array aggregates.

  17. Radar cross section of triangular trihedral reflector with extended bottom plate.

    Energy Technology Data Exchange (ETDEWEB)

    Brock, Billy C.; Doerry, Armin Walter

    2009-05-01

    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. Consequently there is a need for better low grazing angle performance for trihedrals. This is facilitated by extending the bottom plate. A relevant analysis of RCS for an infinite ground plate is presented. Practical aspects are also discussed.

  18. Workforce Information Cubes for NASA

    Data.gov (United States)

    National Aeronautics and Space Administration — Workforce Information Cubes for NASA, sourced from NASA's personnel/payroll system, gives data about who is working where and on what. Includes records for every...

  19. gCube Grid services

    CERN Document Server

    Andrade, Pedro

    2008-01-01

    gCube is a service-based framework for eScience applications requiring collaboratory, on-demand, and intensive information processing. It provides to these communities Virtual Research Environments (VREs) to support their activities. gCube is build on top of standard technologies for computational Grids, namely the gLite middleware. The software was produced by the DILIGENT project and will continue to be supported and further developed by the D4Science project. gCube reflects within its name a three-sided interpretation of the Grid vision of resource sharing: sharing of computational resources, sharing of structured data, and sharing of application services. As such, gCube embodies the defining characteristics of computational Grids, data Grids, and virtual data Grids. Precisely, it builds on gLite middleware for managing distributed computations and unstructured data, includes dedicated services for managing data and metadata, provides services for distributed information retrieval, allows the orchestration...

  20. 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.

  1. Posteromedial Corner Reconstruction

    Science.gov (United States)

    Ferrer, Gonzalo; Leon, Agustín; Wirth, Hans; Mena, Adolfo; Tuca, María José; Espinoza, Gonzalo

    2017-01-01

    Objective: Report the experience, after 1-year follow-up, of 30 patients who underwent anatomical knee reconstruction of posteromedial corner (PMC) injuries, using La Prade´s Technique. Methods: Retrospective cohort study of 30 consecutive patients with PMC injuries operated between November 2010 and May 2014 by the same surgical team. Inclusion criteria: patients with clinical presentation and images (stress radiographs and MRI) compatible with PMC injury, who maintained a grade III chronic instability in spite of at least 3 months of orthopedic treatment, who were reconstructed using La Prade’s anatomical technique, and completed at least 12 months of follow-up. Exclusion criteria: discordance between clinical and image studies, grade I or II medial instability, and surgery performed through a different technique. Data was collected by reviewing the electronic files and images. Functional scores (IKDC and Lysholm) were applied and registered in the preoperative evaluation, and then 6 and 12 months after surgery. Results: Thirty patients (28 men and 2 women) met the inclusion criteria. Mean age was 43 years (24-69). The vast majority (28 patients) had a high-energy mechanism of injury. Twenty patients were diagnosed in the acute setting, while 10 had a delayed diagnosis after poor results of concomitant ligament reconstructions. With the exception of 2 patients, who presented with isolated PMC injury, the majority had associated injuries as detailed: 11 cases had PMC + anterior cruciate ligament (ACL) injury, 3 patients had PMC + posterior cruciate ligament (PCL) injury, 3 patients had PMC + meniscal tears, 9 patients had PMC + ACL + PCL injuries, and there were 2 cases of PMC + ACL + PCL + lateral collateral ligament injuries. Mean time for PMC reconstruction surgery was 5 months (range 2-32). Lysholm and IKDC scores were 18,2 (2-69) and 24,3 (9,2-52,9) respectively in the preoperative setting, improving to 76,7 (44-94) and 70,7 (36,8-95,4) after 1-year follow

  2. 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.

  3. 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.

  4. PowerCube: Integrated Power, Propulsion, and Pointing for CubeSats Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Tethers Unlimited, Inc. proposes to develop the PowerCube, an integrated power, propulsion, and pointing solution for CubeSats. The PowerCube combines three...

  5. 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...

  6. 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.

  7. 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.

  8. 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.

  9. Magnetohydrodynamic (MHD) channel corner seal

    Science.gov (United States)

    Spurrier, Francis R.

    1980-01-01

    A corner seal for an MHD duct includes a compressible portion which contacts the duct walls and an insulating portion which contacts the electrodes, sidewall bars and insulators. The compressible portion may be a pneumatic or hydraulic gasket or an open-cell foam rubber. The insulating portion is segmented into a plurality of pieces of the same thickness as the electrodes, insulators and sidewall bars and aligned therewith, the pieces aligned with the insulator being of a different size from the pieces aligned with the electrodes and sidewall bars to create a stepped configuration along the corners of the MHD channel.

  10. Propulsion for CubeSats

    Science.gov (United States)

    Lemmer, Kristina

    2017-05-01

    At present, very few CubeSats have flown in space featuring propulsion systems. Of those that have, the literature is scattered, published in a variety of formats (conference proceedings, contractor websites, technical notes, and journal articles), and often not available for public release. This paper seeks to collect the relevant publically releasable information in one location. To date, only two missions have featured propulsion systems as part of the technology demonstration. The IMPACT mission from the Aerospace Corporation launched several electrospray thrusters from Massachusetts Institute of Technology, and BricSAT-P from the United States Naval Academy had four micro-Cathode Arc Thrusters from George Washington University. Other than these two missions, propulsion on CubeSats has been used only for attitude control and reaction wheel desaturation via cold gas propulsion systems. As the desired capability of CubeSats increases, and more complex missions are planned, propulsion is required to accomplish the science and engineering objectives. This survey includes propulsion systems that have been designed specifically for the CubeSat platform and systems that fit within CubeSat constraints but were developed for other platforms. Throughout the survey, discussion of flight heritage and results of the mission are included where publicly released information and data have been made available. Major categories of propulsion systems that are in this survey are solar sails, cold gas propulsion, electric propulsion, and chemical propulsion systems. Only systems that have been tested in a laboratory or with some flight history are included.

  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. Local heat transfer around a wall-mounted cube. Case of the attack angle of 45 deg.; Rippotai tokki mawari no kyokusho netsu dentatsu. Katamukikaku 45 degrees no baai

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, H.; Igarashi, T.; Tsutsui, T. [National Defense Academy, Kanagawa (Japan)

    1999-11-25

    An experimental study was performed to investigate the local heat transfer around a cube mounted on the wall. The cube lied in the turbulent boundary layer. The flow angle of attack to the cube was 15 degree. The Reynolds number ranged from 4.2 x 10{sup 3} to 3.3 x 10{sup 4}. The surface temperature distributions around time cube were measured with thermocouples tinder the condition of a constant heat flux. The local h eat transfer is very high near the front corner on the top face of the cube. This high heat transfer region extends from the front corner to downstream along both edges. This is caused by the formation of lamb horn vortex. The local heat transfer is also high in time region of horseshoe vortex formed a round the cube. On the wall behind the cube, there is a pair of minimum heat transfer region. The average Nusselt number on each face of the cube is given as a function of Reynolds number. The overall Nusselt number of time cube is expressed by Nu{sub m}=0.43Re{sup 0.58}. (author)

  13. VT NAD27 Orthophoto Boundaries - corner points

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) RF 5000 scale orthophoto edge lines (4000 x 4000 meter grid cells) were generated automatically from the known corner locations. These corners...

  14. Three Cubes in One Number

    Science.gov (United States)

    Jue, Brian

    2010-01-01

    Separate a three-digit number into its component digits. After raising each digit to the third power and computing the sum of the cubes, determine how often the original number reappears. Modular arithmetic is used to reduce the number of potential solutions to a more manageable quantity. (Contains 4 tables.)

  15. Collection of Recyclables from Cubes

    DEFF Research Database (Denmark)

    Wøhlk, Sanne; Bogh, Morten Bie; Mikkelsen, Hardy

    2014-01-01

    Collection of recyclable materials is a major part of reverse logistics and an important issue in sustainable logistics. In this paper we consider a case study where paper and glass are collected from recycling cubes and transported to a treatment facility where it is processed for reuse. We anal...

  16. Partial cubes: structures, characterizations, and constructions

    CERN Document Server

    Ovchinnikov, Sergei

    2007-01-01

    Partial cubes are isometric subgraphs of hypercubes. Structures on a graph defined by means of semicubes, and Djokovi\\'{c}'s and Winkler's relations play an important role in the theory of partial cubes. These structures are employed in the paper to characterize bipartite graphs and partial cubes of arbitrary dimension. New characterizations are established and new proofs of some known results are given. The operations of Cartesian product and pasting, and expansion and contraction processes are utilized in the paper to construct new partial cubes from old ones. In particular, the isometric and lattice dimensions of finite partial cubes obtained by means of these operations are calculated.

  17. Superconductivity in domains with corners

    DEFF Research Database (Denmark)

    Bonnaillie-Noel, Virginie; Fournais, Søren

    2007-01-01

    We study the two-dimensional Ginzburg-Landau functional in a domain with corners for exterior magnetic field strengths near the critical field where the transition from the superconducting to the normal state occurs. We discuss and clarify the definition of this field and obtain a complete...... asymptotic expansion for it in the large $\\kappa$ regime. Furthermore, we discuss nucleation of superconductivity at the boundary....

  18. Study and simulation for the sharp-corner of silicon-on-insulator waveguides

    Science.gov (United States)

    Sun, De-Gui; Li, Xiaoqi; Wong, Dongxia; Hall, Trevor

    2008-04-01

    The semiconductor industry appears to be encouraging the photonic industry to make highly integrated low-cost optical systems. Planar lightwave circuit (PLC) technology is widely accepted for manufacturing photonic components and Silicon-on-insulator (SOI) waveguides have attracted much research for implementing the highly integrated PLC-based devices. In this work, starting with the guided-mode conversion process and the principle of transportation waves, we mathematically model the structure of corner mirrors of SOI waveguides with a model of effective reflecting interface (ERI). Then we simulate the transfer efficiencies with FDTD method and testify the simulation results with commercial FDTD software tool. Further, we analyze the simulation results and conclude that the conversion efficiency of a corner mirror is determined by several parameters including the geometrical structure, the index-difference of waveguide-reflector materials and the roughness of waveguide-reflector interface. For the corner structure from 90-120°, the optimal transfer efficiency can be achieved more than 98% and the access loss is less than 0.1 dB if the scattering loss of waveguide is not taken into account, but they become 95% and 0.2 dB if the scattering loss is taken into account. For some important PLC components, the deflection angle of 90-120° is good enough for implementing the compact design of highly integrated PLC-based devices.

  19. Nearest Neighbour Corner Points Matching Detection Algorithm

    Directory of Open Access Journals (Sweden)

    Zhang Changlong

    2015-01-01

    Full Text Available Accurate detection towards the corners plays an important part in camera calibration. To deal with the instability and inaccuracies of present corner detection algorithm, the nearest neighbour corners match-ing detection algorithms was brought forward. First, it dilates the binary image of the photographed pictures, searches and reserves quadrilateral outline of the image. Second, the blocks which accord with chess-board-corners are classified into a class. If too many blocks in class, it will be deleted; if not, it will be added, and then let the midpoint of the two vertex coordinates be the rough position of corner. At last, it precisely locates the position of the corners. The Experimental results have shown that the algorithm has obvious advantages on accuracy and validity in corner detection, and it can give security for camera calibration in traffic accident measurement.

  20. 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.

  1. 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.

  2. Inflatable Antenna for CubeSat: Extension of the Previously Developed S-Band Design to the X-Band

    Science.gov (United States)

    Babuscia, Alessandra; Choi, Thomas; Cheung, Kar-Ming; Thangavelautham, Jekan; Ravichandran, Mithun; Chandra, Aman

    2015-01-01

    The inflatable antenna for CubeSat is a 1 meter antenna reflector designed with one side reflective Mylar, another side clear Mylar with a patch antenna at the focus. The development of this technology responds to the increasing need for more capable communication systems to allow CubeSats to operate autonomously in interplanetary missions. An initial version of the antenna for the S-Band was developed and tested in both anechoic chamber and vacuum chamber. Recent developments in transceivers and amplifiers for CubeSat at X-band motivated the extension from the S-Band to the X-Band. This paper describes the process of extending the design of the antenna to the X-Band focusing on patch antenna redesign, new manufacturing challenges and initial results of experimental tests.

  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. High frequency scattering from trihedral corner reflectors and other benchmark targets - SBR versus experiment

    Science.gov (United States)

    Baldauf, John; Lee, Shung-Wu; Lin, Luke; Jeng, Shyh-Kang; Scarborough, Steven M.; Yu, C. L.

    1991-09-01

    A general method for calculating the radar cross section (RCS) from a three-dimensional target is described. The target is first constructed by using a solid-geometry-modeling computer-aided design (CAD) package. Following the shooting and bouncing ray (SBR) method, a very dense grid of rays is launched from the incident direction toward the target. Each ray is traced according to the geometrical optics theory including the effect of ray tube divergence, polarization, and material reflection coefficient. At the point where the ray exits the target, a physical optics-type integration is performed to obtain the scattered far fields. This method is tested using several simple examples involving interaction among plates, cylinders, and spheres. The theoretical results are generally in good agreement with measured data.

  7. Corner stores: the perspective of urban youth.

    Science.gov (United States)

    Sherman, Sandra; Grode, Gabrielle; McCoy, Tara; Vander Veur, Stephanie S; Wojtanowski, Alexis; Sandoval, Brianna Almaguer; Foster, Gary D

    2015-02-01

    We examined the perspectives of low-income, urban youth about the corner store experience to inform the development of corner store interventions. Focus groups were conducted to understand youth perceptions regarding their early shopping experiences, the process of store selection, reasons for shopping in a corner store, parental guidance about corner stores, and what their ideal, or "dream corner store" would look like. Thematic analysis was employed to identify themes using ATLAS.ti (version 6.1, 2010, ATLAS.ti GmbH) and Excel (version 2010, Microsoft Corp). Focus groups were conducted in nine kindergarten-through-grade 8 (K-8) public schools in low-income neighborhoods with 40 fourth- to sixth-graders with a mean age of 10.9±0.8 years. Youth report going to corner stores with family members at an early age. By second and third grades, a growing number of youth reported shopping unaccompanied by an older sibling or adult. Youth reported that the products sold in stores were the key reason they choose a specific store. A small number of youth said their parents offered guidance on their corner store purchases. When youth were asked what their dream corner store would look like, they mentioned wanting a combination of healthy and less-healthy foods. These data suggest that, among low-income, urban youth, corner store shopping starts at a very young age and that product, price, and location are key factors that affect corner store selection. The data also suggest that few parents offer guidance about corner store purchases, and youth are receptive to having healthier items in corner stores. Corner store intervention efforts should target young children and their parents/caregivers and aim to increase the availability of affordable, healthier products. Copyright © 2015 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.

  8. 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.

  9. 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.

  10. Stabilization system for holographic recording of volume Bragg gratings using a corner cube retroreflector.

    Science.gov (United States)

    Ott, Daniel B; Divliansky, Ivan B; Segall, Marc A; Glebov, Leonid B

    2014-02-20

    Volume Bragg gratings serve an important role in laser development as devices that are able to manipulate both the wavelength and angular spectrum of light. A common method for producing gratings is holographic recording of a two collimated beam interference pattern in a photosensitive material. This process requires stability of the recording system at a level of a fraction of the recording wavelength. A new method for measuring and stabilizing the phase of the recording beams is presented that is extremely flexible and simple to integrate into an existing holographic recording setup and independent of the type of recording media. It is shown that the presented method increases visibility of an interference pattern and for photo-thermo-refractive glass enables enhancement of the spatial refractive index modulation. The use of this technique allows for longer recording times that can lead to the use of expanded recording beams for large aperture gratings.

  11. Can corner-cube absolute gravimeters sense the effects of Special Relativity?

    CERN Document Server

    Nagornyi, V D; Zanimonskiy, Y Y

    2012-01-01

    Relativistic treatment of the finite speed of light correction in absolute gravimeters, as evolved by Rothleitner and Francis in Metrologia 2011, 48 442-445, following the initial publication in Metrologia 2011, 48 187-195, leads to spurious conclusions. The double Doppler shift implemented in the gravimeters obliterates the difference between its relativistic and non-relativistic formulation. Optical heterodyning used in Michelson-type interferometers makes the quadratic Lorenz-like term of the double Doppler shift discernable against the linear term, while in relativistic experiments the quadratic term has to be detected against the unit. The disturbance of the registered trajectory caused by the finite speed of light includes tracking signal delay as intrinsic part not reducible to the Doppler shifts.

  12. Posteromedial corner injuries of the knee

    Energy Technology Data Exchange (ETDEWEB)

    House, C.V. [Royal National Orthopaedic Hospital NHS Trust, Stanmore, Middlesex (United Kingdom) and Institute of Orthopaedics and Musculoskeletal Sciences, Stanmore (United Kingdom)]. E-mail: charles.house@uclh.nhs.uk; Connell, D.A. [Royal National Orthopaedic Hospital NHS Trust, Stanmore, Middlesex (United Kingdom); Institute of Orthopaedics and Musculoskeletal Sciences, Stanmore (United Kingdom); Saifuddin, A. [Royal National Orthopaedic Hospital NHS Trust, Stanmore, Middlesex (United Kingdom); Institute of Orthopaedics and Musculoskeletal Sciences, Stanmore (United Kingdom)

    2007-06-15

    Magnetic resonance imaging (MRI) depicts in exquisite detail the supporting structures of the posteromedial corner of the knee. This musculoligamentous unit plays a central role as a dynamic stabilizer of the knee joint and the recognition of injury to the posteromedial corner carries important implications in terms of management and prognosis, most particularly in the anterior cruciate ligament-deficient knee. This article provides a resume of the functional anatomy of the posteromedial corner of the knee as seen with MRI and follows with a review of the MRI appearances of injury to the posteromedial corner.

  13. PowerCube: Integrated Power, Propulsion, and Pointing for CubeSats Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The PowerCube is a 1U CubeSat module that provides integrated propulsion, power, and precision pointing to enable the low-cost CubeSat platform to be used to conduct...

  14. Results from IceCube

    Directory of Open Access Journals (Sweden)

    DeYoung Tyce

    2016-01-01

    Full Text Available Data from the IceCube Neutrino Observatory have revealed the existence of a flux of high energy neutrinos of extraterrestrial origin, which is observed in a number of analyses spanning different energy ranges, fields of view, and neutrino flavors. The current data are consistent with an isotropic, equal-flavor flux described by a simple power law spectrum, but deviations from this simple model cannot yet be constrained with high precision. The existing observations in this area are reviewed, along with recent results on dark matter searches and observations of cosmic rays.

  15. Corner Flow of Power Law Fluids

    DEFF Research Database (Denmark)

    Henriksen, P.; Hassager, Ole

    1989-01-01

    A local analysis of the flow of power law fluids near corners is performed. The equation for the stream function is shown to allow separated solutions in plane polar coordinates. The radial behavior is shown to be algebraic and results are given for the exponent for different values of corner ang...

  16. 3D-Nanomachining using corner lithography

    NARCIS (Netherlands)

    Berenschot, Johan W.; Tas, Niels Roelof; Jansen, Henricus V.; Elwenspoek, Michael Curt

    2008-01-01

    We present a fabrication method to create 3D nano structures without the need for nano lithography. The method, named "corner lithography" is based on conformal deposition and subsequent isotropic thinning of a thin film. The material that remains in sharp concave corners is either used as a mask or

  17. Curiosity Corner. What Works Clearinghouse Intervention Report

    Science.gov (United States)

    What Works Clearinghouse, 2009

    2009-01-01

    "Curiosity Corner" is an early childhood curriculum emphasizing children's language and literacy skills. It comprises two sets of 38 weekly thematic units--one for three-year-olds and one for four-year-olds. Program staff conduct daily lessons using sequential daily activities. One study of "Curiosity Corner" meets the What…

  18. 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.

  19. Vocational Teaching Cube System of Engineering Graphics

    Institute of Scientific and Technical Information of China (English)

    YangDaofu; LiuShenli

    2003-01-01

    Based on long-time research on vocational teaching cube theory in graphics education and analyzing on the intellectual structure in the process of reading engineering drawing, the graphics intellectual three-dimensional model, which is made up of 100 cubes, is founded and tested in higher vocational graphics education. This system serves as a good guidance to the graphics teaching.

  20. Interplanetary CubeSat Navigational Challenges

    Science.gov (United States)

    Martin-Mur, Tomas J.; Gustafson, Eric D.; Young, Brian T.

    2015-01-01

    CubeSats are miniaturized spacecraft of small mass that comply with a form specification so they can be launched using standardized deployers. Since the launch of the first CubeSat into Earth orbit in June of 2003, hundreds have been placed into orbit. There are currently a number of proposals to launch and operate CubeSats in deep space, including MarCO, a technology demonstration that will launch two CubeSats towards Mars using the same launch vehicle as NASA's Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) Mars lander mission. The MarCO CubeSats are designed to relay the information transmitted by the InSight UHF radio during Entry, Descent, and Landing (EDL) in real time to the antennas of the Deep Space Network (DSN) on Earth. Other CubeSatts proposals intend to demonstrate the operation of small probes in deep space, investigate the lunar South Pole, and visit a near Earth object, among others. Placing a CubeSat into an interplanetary trajectory makes it even more challenging to pack the necessary power, communications, and navigation capabilities into such a small spacecraft. This paper presents some of the challenges and approaches for successfully navigating CubeSats and other small spacecraft in deep space.

  1. Teaching group theory using Rubik's cubes

    Science.gov (United States)

    Cornock, Claire

    2015-10-01

    Being situated within a course at the applied end of the spectrum of maths degrees, the pure mathematics modules at Sheffield Hallam University have an applied spin. Pure topics are taught through consideration of practical examples such as knots, cryptography and automata. Rubik's cubes are used to teach group theory within a final year pure elective based on physical examples. Abstract concepts, such as subgroups, homomorphisms and equivalence relations are explored with the cubes first. In addition to this, conclusions about the cubes can be made through the consideration of algebraic approaches through a process of discovery. The teaching, learning and assessment methods are explored in this paper, along with the challenges and limitations of the methods. The physical use of Rubik's cubes within the classroom and examination will be presented, along with the use of peer support groups in this process. The students generally respond positively to the teaching methods and the use of the cubes.

  2. 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...

  3. 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....

  4. 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.

  5. 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

  6. 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).

  7. 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.

  8. Correlation based rotation-invariant corner detector

    Science.gov (United States)

    Mazzaferri, Javier; Ledesma, Silvia

    2008-04-01

    In this work we introduce a new approach for corner extraction. The method that allows the corner extraction with rotation invariance is composed by a spiral phase function and a binary amplitude. The designed function can be easily implemented as a filter for a Vander Lugt-like optical correlator. A final image obtained with the detector presents intensity peaks in each corner location. Numerical simulation has been performed on a set of synthetic scenes, modulated either in amplitude or phase. Results that show the very good performance of the method are shown.

  9. Optimization in Data Cube System Design

    Institute of Scientific and Technical Information of China (English)

    YilongLiang; ShaoweiXia

    2004-01-01

    The design of an OLAP system for supporting real-time queries is one of the major research issues.One approach is to use data cubes,which are pre-computed multidimensional views of data in the data warehouse.An initial set of data cubes can be derived.from which the answer to each frequently asked query can be retrieved directly.However,there are two practical problems concerning the design of a cube based system:1)the maintenance cost of the data cubes,and 2)the query cost to answer a selected set of frequently asked queries.Maintaining a data cube requires disk storage and CPU computation,So the maintenance cost is related to the total size of the data cubes materialized,and thus keeping all data cubes is impractical.The total size of cubes may be reduced by merging some cubes.However,the resulting larger cubes will increase the query cost of answering some queries.If the bounds on maintenance cost and query cost are strict.some of the queries need to be sacrificed.An optimization problem in data cube system design has been defined.With a maintenance-cost bound and a query-cost bound given by the user,it is necessary to opti-mize the initial set of data cubes such that the system can answer a maximum number of queries and satisfy the bounds.This is an NP-complete problem.Approximate algorithms Greedy Removing(GR)and 2-Greedy Merging with Multiple paths(2GGM)are proposed.Experiments have been done on a census database and the results show that our approach in both effbctive and efficient.

  10. Semi-Closed Cube: An Effective Approach to Trading Off Data Cube Size and Query Response Time

    Institute of Scientific and Technical Information of China (English)

    Sheng-En Li; Shan Wang

    2005-01-01

    The results of data cube will occupy huge amount of disk space when the base table is of a large number of attributes. A new type of data cube, compact data cube like condensed cube and quotient cube, was proposed to solve the problem. It compresses data cube dramatically. However, its query cost is so high that it cannot be used in most applications. This paper introduces the semi-closed cube to reduce the size of data cube and achieve almost the same query response time as the data cube does. Semi-closed cube is a generalization of condensed cube and quotient cube and is constructed from a quotient cube. When the query cost of quotient cube is higher than a given threshold, semi-closed cube selects some views and picks a fellow for each of them. All the tuples of those views are materialized except those closed by their fellows. To find a tuple of those views, users only need to scan the view and its fellow. Thus, their query performance is improved. Experiments were conducted using a real-world data set. The results show that semi-closed cube is an effective approach of data cube.

  11. IceCube Results and PINGU Perspectives

    DEFF Research Database (Denmark)

    Koskinen, David Jason

    2015-01-01

    The last three years of IceCube operation with the completed detector have resulted in a plethora of results, including the first observation of high energy astrophysical neutrinos, tests of a possible neutrino flux from atmospheric charm meson decay, and competitive results of neutrino oscillati...... from atmospheric muon neutrino disappearance. Based on the success of IceCube, a new low energy in-fill, known as the Precision IceCube Next Generation Upgrade, is being proposed with the primary physics goal of resolving the ordering of the neutrino mass hierarchy....

  12. Intrinsic viscosity of a suspension of cubes

    KAUST Repository

    Mallavajula, Rajesh K.

    2013-11-06

    We report on the viscosity of a dilute suspension of cube-shaped particles. Irrespective of the particle size, size distribution, and surface chemistry, we find empirically that cubes manifest an intrinsic viscosity [η]=3.1±0.2, which is substantially higher than the well-known value for spheres, [η]=2.5. The orientation-dependent intrinsic viscosity of cubic particles is determined theoretically using a finite-element solution of the Stokes equations. For isotropically oriented cubes, these calculations show [η]=3.1, in excellent agreement with our experimental observations. © 2013 American Physical Society.

  13. A Shell Multi-dimensional Hierarchical Cubing Approach for High-Dimensional Cube

    Science.gov (United States)

    Zou, Shuzhi; Zhao, Li; Hu, Kongfa

    The pre-computation of data cubes is critical for improving the response time of OLAP systems and accelerating data mining tasks in large data warehouses. However, as the sizes of data warehouses grow, the time it takes to perform this pre-computation becomes a significant performance bottleneck. In a high dimensional data warehouse, it might not be practical to build all these cuboids and their indices. In this paper, we propose a shell multi-dimensional hierarchical cubing algorithm, based on an extension of the previous minimal cubing approach. This method partitions the high dimensional data cube into low multi-dimensional hierarchical cube. Experimental results show that the proposed method is significantly more efficient than other existing cubing methods.

  14. VT NAD83 Orthophoto Boundaries - corner points

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) RF 5000 NAD83 orthophoto edge lines (4000 x 4000 meter grid cells) were generated automatically from the known corner locations (generated by Gary...

  15. 3Corners of the World / Joosep Sang

    Index Scriptorium Estoniae

    Sang, Joosep

    2009-01-01

    Arvustused : Robert Jürjendal, Petri Kuljuntausta, David Rothenberg. 3Corners of the World. [Tallinn] : Terra Nova Music, 2008. Nadia ja Fragile. Uhke ali. [Tallinn] : Nadia & Fragile, 2008. UMA. Civitas Soli. [Tallinn] : Elwood, 2008. Uutest heliplaatidest

  16. 3Corners of the World / Joosep Sang

    Index Scriptorium Estoniae

    Sang, Joosep

    2009-01-01

    Arvustused : Robert Jürjendal, Petri Kuljuntausta, David Rothenberg. 3Corners of the World. [Tallinn] : Terra Nova Music, 2008. Nadia ja Fragile. Uhke ali. [Tallinn] : Nadia & Fragile, 2008. UMA. Civitas Soli. [Tallinn] : Elwood, 2008. Uutest heliplaatidest

  17. Establishment of a corner turning test capability

    Energy Technology Data Exchange (ETDEWEB)

    Ashcraft, R.W.; West, G.T.

    1978-11-01

    A corner turning test capability has been established. While the test is not suited to be the sole criterion for lot qualification, it provides valuable information regarding explosive behavior near failure. Light enhancement and film record analysis techniques are discussed.

  18. Predominance of sperm motion in corners

    Science.gov (United States)

    Nosrati, Reza; Graham, Percival J.; Liu, Qiaozhi; Sinton, David

    2016-05-01

    Sperm migration through the female tract is crucial to fertilization, but the role of the complex and confined structure of the fallopian tube in sperm guidance remains unknown. Here, by confocal imaging microchannels head-on, we distinguish corner- vs. wall- vs. bulk-swimming bull sperm in confined geometries. Corner-swimming dominates with local areal concentrations as high as 200-fold that of the bulk. The relative degree of corner-swimming is strongest in small channels, decreases with increasing channel size, and plateaus for channels above 200 μm. Corner-swimming remains predominant across the physiologically-relevant range of viscosity and pH. Together, boundary-following sperm account for over 95% of the sperm distribution in small rectangular channels, which is similar to the percentage of wall swimmers in circular channels of similar size. We also demonstrate that wall-swimming sperm travel closer to walls in smaller channels (~100 μm), where the opposite wall is within the hydrodynamic interaction length-scale. The corner accumulation effect is more than the superposition of the influence of two walls, and over 5-fold stronger than that of a single wall. These findings suggest that folds and corners are dominant in sperm migration in the narrow (sub-mm) lumen of the fallopian tube and microchannel-based sperm selection devices.

  19. Stability of Roundheads Armoured with Cubes

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Haagensen, Per; Macineira, Enrique

    2003-01-01

      The paper presents the results of a hydraulic model test study of the influence of concrete mass density and placement method on the stability of cube armour in a 1:2 slope cone shaped roundhead exposed to short ? crested seas. Location and development of armour displacements were studied...... for concrete cubes with mass density of 2.4 t/m 3 and 2.8 t/m 3 in random and regular placement. Significant increase in stability for the higher mass density cubes was found showing that the same dimension cubes can be used in roundhead and trunk, if for the top layer of the most exposed part of the roundhead...

  20. A quadrilateralized spherical cube Earth data base

    Science.gov (United States)

    Chan, F. K.

    1980-01-01

    A quadrilateralized spherical cube was constructed to form the basis for the rapid storage and retrieval of high resolution data obtained of the Earth's surface. The structure of this data base was derived from a spherical cube, which was obtained by radially projecting a cube onto its circumscribing sphere. An appropriate set of curvilinear coordinates were chosen such that the resolution cells on the spherical cube were of equal area and were also of essentially the same shape. The main properties of the Earth data base were that the indexing scheme was binary and telescopic in nature, the resolution cells were strung together in a two dimensional manner, the cell addresses were easily computed, and the conversion from geographic to data base coordinates was comparatively simple. It was concluded that this data base structure was perhaps the most viable one for handling remotely sensed data obtained by satellites.

  1. Stability of Roundheads Armoured with Cubes

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Haagensen, Per; Macineira, Enrique

    2003-01-01

    The paper presents the results of a hydraulic model test study of the influence of concrete mass density and placement method on the stability of cube armour in a 1:2 slope cone shaped roundhead exposed to short ? crested seas. Location and development of armour displacements were studied...... for concrete cubes with mass density of 2.4 t/m 3 and 2.8 t/m 3 in random and regular placement. Significant increase in stability for the higher mass density cubes was found showing that the same dimension cubes can be used in roundhead and trunk, if for the top layer of the most exposed part of the roundhead...

  2. WIENER INDEX AND HOSOYA POLYNOMIAL OF FIBONACCI AND LUCAS CUBES

    OpenAIRE

    Klavzar, Sandi; Mollard, Michel

    2011-01-01

    In the language of mathematical chemistry, Fibonacci cubes can be defined as the resonance graphs of fibonacenes. Lucas cubes form a symmetrization of Fibonacci cubes and appear as resonance graphs of cyclic polyphenantrenes. In this paper it is proved that the Wiener index of Fibonacci cubes can be written as the sum of products of four Fibonacci numbers which in turn yields a closed formula for the Wiener index of Fibonacci cubes. Asymptotic behavior of the average distance of Fibonacci cub...

  3. IceCube: physics, status, and future

    OpenAIRE

    Hultqvist, Klas; collaboration, for the IceCube

    2010-01-01

    The IceCube observatory is the first cubic kilometre scale instrument in the field of high-energy neutrino astronomy and cosmic rays. In 2009, following five successful deployment seasons, IceCube consisted of 59 strings of optical modules in the South Pole ice, together with 118 air shower detectors in the IceTop surface array. The range of physics topics includes neutrino signals from astrophysical sources, dark matter, exotic particle physics, cosmic rays, and atmospheric neutrinos. The cu...

  4. 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.

  5. 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...

  6. 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.

  7. 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).

  8. SpaceCube Version 1.5

    Science.gov (United States)

    Geist, Alessandro; Lin, Michael; Flatley, Tom; Petrick, David

    2013-01-01

    SpaceCube 1.5 is a high-performance and low-power system in a compact form factor. It is a hybrid processing system consisting of CPU (central processing unit), FPGA (field-programmable gate array), and DSP (digital signal processor) processing elements. The primary processing engine is the Virtex- 5 FX100T FPGA, which has two embedded processors. The SpaceCube 1.5 System was a bridge to the SpaceCube 2.0 and SpaceCube 2.0 Mini processing systems. The SpaceCube 1.5 system was the primary avionics in the successful SMART (Small Rocket/Spacecraft Technology) Sounding Rocket mission that was launched in the summer of 2011. For SMART and similar missions, an avionics processor is required that is reconfigurable, has high processing capability, has multi-gigabit interfaces, is low power, and comes in a rugged/compact form factor. The original SpaceCube 1.0 met a number of the criteria, but did not possess the multi-gigabit interfaces that were required and is a higher-cost system. The SpaceCube 1.5 was designed with those mission requirements in mind. The SpaceCube 1.5 features one Xilinx Virtex-5 FX100T FPGA and has excellent size, weight, and power characteristics [4×4×3 in. (approx. = 10×10×8 cm), 3 lb (approx. = 1.4 kg), and 5 to 15 W depending on the application]. The estimated computing power of the two PowerPC 440s in the Virtex-5 FPGA is 1100 DMIPS each. The SpaceCube 1.5 includes two Gigabit Ethernet (1 Gbps) interfaces as well as two SATA-I/II interfaces (1.5 to 3.0 Gbps) for recording to data drives. The SpaceCube 1.5 also features DDR2 SDRAM (double data rate synchronous dynamic random access memory); 4- Gbit Flash for storing application code for the CPU, FPGA, and DSP processing elements; and a Xilinx Platform Flash XL to store FPGA configuration files or application code. The system also incorporates a 12 bit analog to digital converter with the ability to read 32 discrete analog sensor inputs. The SpaceCube 1.5 design also has a built

  9. 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

  10. 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...

  11. Probabilistic Parsing Using Left Corner Language Models

    CERN Document Server

    Manning, C D; Manning, Christopher D.; Carpenter, Bob

    1997-01-01

    We introduce a novel parser based on a probabilistic version of a left-corner parser. The left-corner strategy is attractive because rule probabilities can be conditioned on both top-down goals and bottom-up derivations. We develop the underlying theory and explain how a grammar can be induced from analyzed data. We show that the left-corner approach provides an advantage over simple top-down probabilistic context-free grammars in parsing the Wall Street Journal using a grammar induced from the Penn Treebank. We also conclude that the Penn Treebank provides a fairly weak testbed due to the flatness of its bracketings and to the obvious overgeneration and undergeneration of its induced grammar.

  12. Utilizing Probabilistic Linear Equations in Cube Attacks

    Institute of Scientific and Technical Information of China (English)

    Yuan Yao; Bin Zhang; Wen-Ling Wu

    2016-01-01

    Cube attacks, proposed by Dinur and Shamir at EUROCRYPT 2009, have shown huge power against stream ciphers. In the original cube attacks, a linear system of secret key bits is exploited for key recovery attacks. However, we find a number of equations claimed linear in previous literature actually nonlinear and not fit into the theoretical framework of cube attacks. Moreover, cube attacks are hard to apply if linear equations are rare. Therefore, it is of significance to make use of probabilistic linear equations, namely nonlinear superpolys that can be approximated by linear expressions effectively. In this paper, we suggest a way to test out and utilize these probabilistic linear equations, thus extending cube attacks to a wider scope. Concretely, we employ the standard parameter estimation approach and the sequential probability ratio test (SPRT) for linearity test in the preprocessing phase, and use maximum likelihood decoding (MLD) for solving the probabilistic linear equations in the online phase. As an application, we exhibit our new attack against 672 rounds of Trivium and reduce the number of key bits to search by 7.

  13. 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...

  14. 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.

  15. 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...

  16. 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...

  17. 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

  18. 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)

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. Enumeration of Hamiltonian Cycles in 6-cube

    CERN Document Server

    Deza, Michel

    2010-01-01

    Finding the number 2H6 of directed Hamiltonian cycles in 6-cube is problem 43 in Section 7.2.1.1 of Knuth's ' The Art of Computer Programming'; various proposed estimates are surveyed below. We computed exact value: H6=14,754,666,508,334,433,250,560=6*2^4*217,199*1,085,989*5,429,923. Also the number Aut6 of those cycles up to automorphisms of 6-cube was computed as 147,365,405,634,413,085

  4. Better Lunar Ranges with Fewer Photons - Resolving the Lunar Retro-reflectors

    CERN Document Server

    Scheffer, L K

    2005-01-01

    Because of lunar librations, the retroreflectors left on the moon do not, in general, face directly at the Earth. Usually this is regarded as a disadvantage. It results in a spread of arrival times, because each cube that comprises the retroreflector is at a slightly different distance from the earth. However, we can turn this same effect into an advantage. Using pulses and detectors somewhat faster than those currently used for lunar ranging, we can resolve at least some of the structure of a retroreflector, at least when the libration angles are large. This additional structure in the transfer function means that a unique mm level fit can be obtained with many fewer photons. Fitting to the expected reflector transfer function in general requires fewer photons than straight averaging, and smoothly reduces to averaging in the cases where no structure can be resolved. The gains from resolving the reflectors are largest at large libration angles, exactly the case where averaging is most inefficient. In these ca...

  5. HyperCube: a hyperspectral CubeSat constellation for measurements of 3D winds

    Science.gov (United States)

    Glumb, Ronald; Lapsley, Michael; Luce, Scott; Déry, Jean-Philippe; Scott, Deron; Nielsen, Tim

    2016-09-01

    Global measurements of vertically resolved atmospheric wind profiles offer the potential for improved weather forecasts and superior predictions of atmospheric wind patterns. Harris' HyperCube constellation of twelve 6U hyperspectral CubeSats can provide measurements of global tropospheric wind profiles from space at very low cost. It is a commercially funded enterprise in which the data from the satellites is provided to users on a subscription basis. This requires that the design of each satellite be optimized for minimum cost, yet with a reasonably long service life. This paper will focus on the design, operations, and projected performance of the HyperCube system.

  6. Incremental Maintenance of Quotient Cube Based on Galois Lattice

    Institute of Scientific and Technical Information of China (English)

    Cui-PingLi; Kum-HoeTung; ShanWang

    2004-01-01

    Data cube computation is a well-known expensive operation and has been studied extensively. It is often not feasible to compute a complete data cube due to the huge storage requirement. Recently proposed quotient cube addressed this fundamental issue through a partitioning method that groups cube cells into equivalent partitions. The effectiveness and efficiency of the quotient cube for cube compression and computation have been proved. However, as changes axe made to the data sources, to maintain such a quotient cube is non-trivial since the equivalent classes in it must be split or merged. In this paper, incremental algorithms are designed to update existing quotient cube efficiently based on Galois lattice. Performance study shows that these algorithms are efficient and scalable for large databases.

  7. Incremental Maintenance of Quotient Cube Based on Galois Lattice

    Institute of Scientific and Technical Information of China (English)

    Cui-Ping Li; Kum-Hoe Tung; Shan Wang

    2004-01-01

    Data cube computation is a well-known expensive operation and has been studied extensively. It is often not feasible to compute a complete data cube due to the huge storage requirement. Recently proposed quotient cube addressed this fundamental issue through a partitioning method that groups cube cells into equivalent partitions. The effectiveness and efficiency of the quotient cube for cube compression and computation have been proved. However, as changes are made to the data sources, to maintain such a quotient cube is non-trivial since the equivalent classes in it must be split or merged. In this paper, incremental algorithms are designed to update existing quotient cube efficiently based on Galois lattice. Performance study shows that these algorithms are efficient and scalable for large databases.

  8. Universal corner entanglement from twist operators

    CERN Document Server

    Bueno, Pablo; Witczak-Krempa, William

    2015-01-01

    The entanglement entropy in three-dimensional conformal field theories (CFTs) receives a logarithmic contribution characterized by a regulator-independent function $a(\\theta)$ when the entangling surface contains a sharp corner with opening angle $\\theta$. In the limit of a smooth surface ($\\theta\\rightarrow\\pi$), this corner contribution vanishes as $a(\\theta)=\\sigma\\,(\\theta-\\pi)^2$. In arXiv:1505.04804, we provided evidence for the conjecture that for any $d=3$ CFT, this corner coefficient $\\sigma$ is determined by $C_T$, the coefficient appearing in the two-point function of the stress tensor. Here, we argue that this is a particular instance of a much more general relation connecting the analogous corner coefficient $\\sigma_n$ appearing in the $n$th R\\'enyi entropy and the scaling dimension $h_n$ of the corresponding twist operator. In particular, we find the simple relation $h_n/\\sigma_n=(n-1)\\pi$. We show how it reduces to our previous result as $n\\rightarrow 1$, and explicitly check its validity for f...

  9. Delamination of Compressed Thin Layers at Corners

    DEFF Research Database (Denmark)

    Sørensen, Kim D.; Jensen, Henrik Myhre; Clausen, Johan

    2008-01-01

    An analysis of delamination for a thin elastic layer under compression, attached to a substrate at a corner is carried out. The analysis is performed by combining results from interface fracture mechanics and the theory of thin shells. In contrast with earlier results for delamination on a flat...... layers, Fracture mechanics, Crack closure, Steady state crack propagation....

  10. Delamination of Compressed Thin Layers at Corners

    DEFF Research Database (Denmark)

    Sørensen, Kim Dalsten; Jensen, Henrik Myhre; Clausen, Johan

    2008-01-01

    An analysis of delamination for a thin elastic layer under compression, attached to a substrate at a corner is carried out. The analysis is performed by combining results from interface fracture mechanics and the theory of thin shells. In contrast with earlier results for delamination on a flat...

  11. Corner diffraction coefficients for the quarter plane

    DEFF Research Database (Denmark)

    Hansen, Thorkild B.

    1991-01-01

    The current near a right-angled corner on a perfectly conducting flat scatterer illuminated by a plane wave is expressed as a sum of three currents. The first is the physical optics current, which describes the surface effect. The second is the fringe wave current, which is found from the half-pl...

  12. Delamination of Compressed thin Layers at Corners

    DEFF Research Database (Denmark)

    Clausen, Johan; Jensen, Henrik Myhre; Sørensen, Kim Dalsten

    2008-01-01

    An analysis of delamination for a thin elastic film, attached to a substrate with a corner, is carried out. The film is in compression and the analysis is performed by combining results from fracture mechanics and the theory of thin shells. The results show a very strong dependency of the angle...

  13. FNS Research Corner: Summary of Research

    Science.gov (United States)

    Berman, Danielle; Burdg, Jinee

    2017-01-01

    The FNS Research Corner provides a continuing series to summarize recently completed and current research conducted by the U.S. Department of Agriculture's Food and Nutrition Service (FNS) in the area of child nutrition. For further information, contact the Office of Policy Support (OPS) at (703) 305-2117. Links to published studies and reports as…

  14. Composition: Around Corners (2006-08)

    DEFF Research Database (Denmark)

    Bergstrøm-Nielsen, Carl

    2010-01-01

    Around Corners is an open composition to be realised by improvising musicians. See more about my composition practise in the entry "Composition - General Introduction". Caution: streaming the sound/video files will in some cases only provide a few minutes' sample, or the visuals will not appear...

  15. 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.

  16. 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.

  17. IceCube: A Cubic Kilometer Radiation Detector

    OpenAIRE

    Klein, S.; IceCube Collaboration

    2008-01-01

    IceCube is a 1 km^3 neutrino detector now being built at the Amundsen-Scott South Pole Station. It consists of 4800 Digital Optical Modules (DOMs) which detect Cherenkov radiation from the charged particles produced in neutrino interactions. IceCube will observe astrophysical neutrinos with energies above about 100 GeV. IceCube will be able to separate \

  18. Locking Corners Speed Solar-Array Frame Assembly

    Science.gov (United States)

    Olah, S.; Sampson, W. J.

    1984-01-01

    Mitered corners of solar-array frames joined together by single angle brace and two springs. Locking corner braces and mating frame members pushed together by hand or assembled automatically. Fastening system used to assemble window screens and picture frames.

  19. PMC: Select Materialized Cells in Data Cubes

    Institute of Scientific and Technical Information of China (English)

    Hong-Song Li; Hou-Kuan Huang

    2006-01-01

    QC-Tree is one of the most storage-efficient structures for data cubes in an MOLAP system. Although QC-Tree can achieve a high compression ratio, it is still a fully materialized data cube. In this paper, an improved structure PMC is presented allowing us to materialize only a part of the cells in a QC-Tree to save more storage space. There is a notable difference between our partially materialization algorithm and traditional materialized views selection algorithms. In a traditional algorithm, when a view is selected, all the cells in this view are to be materialized. Otherwise, if a view is not selected, all the cells in this view will not be materialized. This strategy results in the unstable query performance. The presented algorithm, however, selects and materializes data in cell level, and, along with further reduced space and update cost, it can ensure a stable query performance. A series of experiments are conducted on both synthetic and real data sets. The results show that PMC can further reduce storage space occupied by the data cube, and can shorten the time to update the cube.

  20. Teaching Group Theory Using Rubik's Cubes

    Science.gov (United States)

    Cornock, Claire

    2015-01-01

    Being situated within a course at the applied end of the spectrum of maths degrees, the pure mathematics modules at Sheffield Hallam University have an applied spin. Pure topics are taught through consideration of practical examples such as knots, cryptography and automata. Rubik's cubes are used to teach group theory within a final year pure…

  1. Pre- to Post- CubeSats

    Science.gov (United States)

    Cutler, J.

    2015-12-01

    CubeSats sprung from a formative picosatellite effort at a university in the heart of Silicon Valley, took root in a university-led university environment, and have grown into complex-shaped explorers in both near and soon-to-be deep space. Private citizens, businesses, government are building and launching a variety of science, technology demonstration, and service missions. A new generation of space explorers is gaining first hand experience in space missions at all educational levels. There is new life and new energy in the space program. However, space is still difficult. The environment is harsh. Funding is sparse. This talk explores this history and the future of CubeSats from the context of a university-centric laboratory that emphasizes teaching, research, and entrepreneurial impact. It will explore the following questions: What sparked the CubeSat innovation? What are longer lasting lessons of this community? Where are places we can go next? What does it take to get there? The talk will draw on lessons learned from building over six on-orbit CubeSat missions and training hundreds of space engineers.

  2. 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...

  3. 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.

  4. 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.

  5. 49 CFR 231.29 - Road locomotives with corner stairways.

    Science.gov (United States)

    2010-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD SAFETY APPLIANCE STANDARDS § 231.29 Road locomotives with corner stairways. After September 30, 1979, road locomotives with corner stairway openings must be... 49 Transportation 4 2010-10-01 2010-10-01 false Road locomotives with corner stairways....

  6. Corner Detection Based on Human Visual System Model

    Institute of Scientific and Technical Information of China (English)

    LU Xiaoguang; ZHOU Jie

    2001-01-01

    Corners are useful features in computer vision tasks.In this paper,we present an algorithm for corner detection based on a human visual system model.Experimental results proved that it ismore effective than conventional corner detector under uneven illumination conditions.

  7. The exact evaluation of the corner-to-corner resistance of an M x N resistor network: asymptotic expansion

    Energy Technology Data Exchange (ETDEWEB)

    Essam, J W [Department of Mathematics, Royal Holloway College, University of London, Egham, Surrey TW20 0EX (United Kingdom); Wu, F Y [Department of Physics, Northeastern University, Boston, MA 02115 (United States)

    2009-01-16

    We study the corner-to-corner resistance of an M x N resistor network with resistors r and s in the two spatial directions and obtain an asymptotic expansion of its exact expression for large M and N.

  8. GreenCube and RocketCube: Low-Resource Sensorcraft for Atmospheric and Ionospheric Science

    Science.gov (United States)

    Bracikowski, P. J.; Lynch, K. A.; Slagle, A. K.; Fagin, M. H.; Currey, S. R.; Siddiqui, M. U.

    2009-12-01

    In situ atmospheric and ionospheric studies benefit greatly from the ability to separate variations in space from variations in time. Arrays of many probes are a method of doing this, but because of the technical character and expense of developing large arrays, so far probe arrays have been the domain of well-funded science missions. CubeSats and low-resource craft (``Picosats") are an avenue for bringing array-based studies of the atmosphere and ionosphere into the mainstream. The Lynch Rocket Lab at Dartmouth College is attempting to develop the instruments, experience, and heritage to implement arrays of many low-resource sensorcraft while doing worthwhile science in the development process. We are working on two CubeSat projects to reach this goal: GreenCube for atmospheric studies and RocketCube for ionospheric studies. GreenCube is an undergraduate student-directed high-altitude balloon-borne 3U CubeSat. GreenCube I was a bus, telemetry, and mechanical system development project. GreenCube I flew in the fall of 2008. The flight was successfully recovered and tracked over the 97km range and through the 29km altitude rise. GreenCube I carried six thermal housekeeping sensors, a GPS, a magnetometer, and a HAM radio telemetry system with a reporting rate of once every 30 seconds. The velocity profile obtained from the GPS data implies the presence of atmospheric gravity waves during the flight. GreenCube II flew in August 2009 with the science goal of detecting atmospheric gravity waves over the White Mountains of New Hampshire. Two balloons with identical payloads were released 90 seconds apart to make 2-point observations. Each payload carried a magnetometer, 5 thermistors for ambient temperature readings, a GPS, and an amateur radio telemetry system with a 7 second reporting cadence. A vertically oriented video camera on one payload and a horizontally oriented video camera on the other recorded the characteristics of gravity waves in the nearby clouds. We

  9. CubeSat evolution: Analyzing CubeSat capabilities for conducting science missions

    Science.gov (United States)

    Poghosyan, Armen; Golkar, Alessandro

    2017-01-01

    Traditionally, the space industry produced large and sophisticated spacecraft handcrafted by large teams of engineers and budgets within the reach of only a few large government-backed institutions. However, over the last decade, the space industry experienced an increased interest towards smaller missions and recent advances in commercial-off-the-shelf (COTS) technology miniaturization spurred the development of small spacecraft missions based on the CubeSat standard. CubeSats were initially envisioned primarily as educational tools or low cost technology demonstration platforms that could be developed and launched within one or two years. Recently, however, more advanced CubeSat missions have been developed and proposed, indicating that CubeSats clearly started to transition from being solely educational and technology demonstration platforms to offer opportunities for low-cost real science missions with potential high value in terms of science return and commercial revenue. Despite the significant progress made in CubeSat research and development over the last decade, some fundamental questions still habitually arise about the CubeSat capabilities, limitations, and ultimately about their scientific and commercial value. The main objective of this review is to evaluate the state of the art CubeSat capabilities with a special focus on advanced scientific missions and a goal of assessing the potential of CubeSat platforms as capable spacecraft. A total of over 1200 launched and proposed missions have been analyzed from various sources including peer-reviewed journal publications, conference proceedings, mission webpages as well as other publicly available satellite databases and about 130 relatively high performance missions were downselected and categorized into six groups based on the primary mission objectives including "Earth Science and Spaceborne Applications", "Deep Space Exploration", "Heliophysics: Space Weather", "Astrophysics", "Spaceborne In Situ

  10. Edge and corner detection by color invariants

    Science.gov (United States)

    Chu, Jun; Miao, Jun; Zhang, Guimei; Wang, Lu

    2013-02-01

    Gray-based features are widely used in computer vision applications, while image color is a very important source, which can provide more feature information. To fully exploit color data, a color saturation invariant based on dichromatic reflection model is first constructed. The invariant is an object reflectance property independent of viewpoint and illumination direction. The saturation invariant is then synthesized with existing hue invariant to detect edge and corner features in color image. Experiments show that the detection method proposed here can more effectively tap into color information and achieve true target features due to its lower sensitivity to shadow, shading and highlight. Moreover, when comparing with many other existing edges and corners detecting methods, experimental results demonstrate that the proposed method performs better in detection accurate and effective.

  11. Scaphoid excision with four-corner fusion.

    Science.gov (United States)

    Enna, Matthew; Hoepfner, Peter; Weiss, Arnold-Peter C

    2005-11-01

    The scaphoid plays a critical role in maintain-ing normal carpal kinematics. SLAC and SNAC wrist arthritis demonstrate the ramifications ofscaphoid pathology on wrist biomechanics. In the past, symptomatic SLAC or SNAC pathology spelled total wrist arthrodesis. Over the past 20 years there has been a movement toward limited wrist arthrodesis in the treatment of SLAC/SNAC wrists. In the long-term follow-up of four-corner fusions, patient satisfaction is high, patients are able to return to their previous vocation, and wrist function averages 60%-70% of the contralateral wrist. The Spider plate is a recent advancement in the four-corner fusion armamentarium that has thus far shown great promise in respect to fusion rates (100% in the first documented series [36]),functional range of motion, intercarpal stability[37], and patient satisfaction.

  12. Modeling interconnect corners under double patterning misalignment

    Science.gov (United States)

    Hyun, Daijoon; Shin, Youngsoo

    2016-03-01

    Publisher's Note: This paper, originally published on March 16th, was replaced with a corrected/revised version on March 28th. If you downloaded the original PDF but are unable to access the revision, please contact SPIE Digital Library Customer Service for assistance. Interconnect corners should accurately reflect the effect of misalingment in LELE double patterning process. Misalignment is usually considered separately from interconnect structure variations; this incurs too much pessimism and fails to reflect a large increase in total capacitance for asymmetric interconnect structure. We model interconnect corners by taking account of misalignment in conjunction with interconnect structure variations; we also characterize misalignment effect more accurately by handling metal pitch at both sides of a target metal independently. Identifying metal space at both sides of a target metal.

  13. Universal corner contributions to entanglement negativity

    CERN Document Server

    Kim, Keun-Young; Pang, Da-Wei

    2016-01-01

    It has been realised that corners in entangling surfaces can induce new universal contributions to the entanglement entropy and R\\'enyi entropy. In this paper we study universal corner contributions to entanglement negativity in three- and four-dimensional CFTs using both field theory and holographic techniques. We focus on the quantity $\\chi$ defined by the ratio of the universal part of the entanglement negativity over that of the entanglement entropy, which may characterise the amount of distillable entanglement. We find that for most of the examples $\\chi$ takes bigger values for singular entangling regions, which may suggest increase in distillable entanglement. However, there also exist counterexamples where distillable entanglement decreases for singular surfaces. We also explore the behaviour of $\\chi$ as the coupling varies and observe that for singular entangling surfaces, the amount of distillable entanglement is mostly largest for free theories, while counterexample exists for free Dirac fermion i...

  14. Metal nanoparticles with sharp corners: Universal properties of plasmon resonances

    CERN Document Server

    Sturman, B; Gorkunov, M

    2012-01-01

    We predict the simultaneous occurrence of two fundamental phenomena for metal nanoparticles possessing sharp corners: First, the main plasmonic dipolar mode experiences strong red shift with decreasing corner curvature radius; its resonant frequency is controlled by the apex angle of the corner and the normalized (to the particle size) corner curvature. Second, the split-off plasmonic mode experiences strong localization at the corners. Altogether, this paves the way for tailoring of metal nano-structures providing wavelength-selective excitation of localized plasmons and a strong near-field enhancement of linear and nonlinear optical phenomena.

  15. Brilliant Corners: Approaches to Jazz and Comics

    Directory of Open Access Journals (Sweden)

    Nicolas Pillai

    2016-08-01

    Full Text Available The call for papers Brilliant Corners: Approaches to Jazz and Comics was published on 30 July 2015. In it, the editors made a public invitation for scholarship that proposed meeting points between the disciplines of jazz studies and comics studies. This editorial discusses the motivations for the collection, the editorial methodology, and the research articles included. Finally, the editors suggest some areas in which jazz studies and comics scholarship might address under-researched and fertile topics.

  16. Sharp contact corners, fretting and cracks

    Directory of Open Access Journals (Sweden)

    D. A. Hills

    2013-07-01

    Full Text Available Contacts with sharp edges subject to oscillatory loading are likely to nucleate cracks from the corners, if the loading is sufficiently severe. To a first approximation, the corners behave like notches, where the local elastic behaviour is relieved by plasticity, and which in turn causes irreversibilities that give rise to crack nucleation, but also by frictional slip. One question we aim to answer here is; when is the frictional slip enveloped by plastic slip, so that the corner is effectively a notch in a monolithic material? We do this by employing the classical Williams asymptotic solution to model the contact corner, and, in doing so, we render the solution completely general in the sense that it is independent of the overall geometry of the components. We then re-define the independent parameters describing the properties of the Williams solution by using the inherent length scale, a procedure that was described at the first IJFatigue and FFEMS joint workshop [1]. By proceeding in this way, we can provide a self-contained solution that can be ‘pasted in’ to any complete contact problem, and hence the likelihood of crack nucleation, and the circumstances under which it might occur, can be classified. Further, this reformulation of Williams' solution provides a clear means of obtaining the strength (defined by crack nucleation conditions of a material pair with a particular contact angle. This means that the results from a test carried out using a laboratory specimen may easily be carried over to any complicated contact problem found in engineering practice, and a mechanical test of the prototypical geometry, which may often be quite difficult, is avoided.

  17. Capillary Flow in an Interior Corner

    Science.gov (United States)

    Weislogel, Mark Milton

    1996-01-01

    The design of fluids management processes in the low-gravity environment of space requires an accurate model and description of capillarity-controlled flow in containers of irregular geometry. Here we consider the capillary rise of a fluid along an interior corner of a container following a rapid reduction in gravity. The analytical portion of the work presents an asymptotic formulation in the limit of a slender fluid column, slight surface curvature along the corner, small inertia, and low gravity. New similarity solutions are found and a list of closed form expressions is provided for flow rate and column length. In particular, it is found that the flow is proportional to t(exp 1/2) for a constant height boundary condition, t(exp 2/5) for a spreading drop, and t(exp 3/5) for constant flow. In the experimental portion of the work, measurements from a 2.2s drop tower are reported. An extensive data set, collected over a previously unexplored range of flow parameters, includes estimates of repeatability and accuracy, the role of inertia and column slenderness, and the effects of corner angle, container geometry, and fluid properties. Comprehensive comparisons are made which illustrate the applicability of the analytic results to low-g fluid systems design.

  18. 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.

  19. On-Orbit Thermal Design and Validation of 1 U Standardized CubeSat of STEP Cube Lab

    Directory of Open Access Journals (Sweden)

    Soo-Jin Kang

    2016-01-01

    Full Text Available The Cube Laboratory for Space Technology Experimental Projects (STEP Cube Lab is a cube satellite (CubeSat classified as a pico-class satellite of 1 U (unit size. Its main mission objective is to exploit core space technologies researched by domestic universities and verify the effectiveness of these technologies through on-orbit tests using the CubeSat. To guarantee a successful mission under extreme space thermal environments, proper thermal design is important. This paper describes the development process undertaken in the thermal design of the STEP Cube Lab, based on a passive approach, and its validation test. The system functionality and thermal design were verified through thermal vacuum and thermal balance tests under space simulated thermal vacuum environment condition. Finally, the orbital temperature of each component was predicted using a highly reliable correlated thermal mathematical model of the CubeSat obtained from the thermal balance test.

  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. 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.

  4. 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 ...

  5. AstroVis: Visualizing astronomical data cubes

    Science.gov (United States)

    Finniss, Stephen; Tyler, Robin; Questiaux, Jacques

    2016-08-01

    AstroVis enables rapid visualization of large data files on platforms supporting the OpenGL rendering library. Radio astronomical observations are typically three dimensional and stored as data cubes. AstroVis implements a scalable approach to accessing these files using three components: a File Access Component (FAC) that reduces the impact of reading time, which speeds up access to the data; the Image Processing Component (IPC), which breaks up the data cube into smaller pieces that can be processed locally and gives a representation of the whole file; and Data Visualization, which implements an approach of Overview + Detail to reduces the dimensions of the data being worked with and the amount of memory required to store it. The result is a 3D display paired with a 2D detail display that contains a small subsection of the original file in full resolution without reducing the data in any way.

  6. 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...

  7. 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.

  8. 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.

  9. New Physics with IceCube

    CERN Document Server

    Reynoso, M M; Reynoso, Matias M.; Sampayo, Oscar A.

    2007-01-01

    IceCube, a cubic kilometer neutrino telescope will be capable to probe neutrino-nucleon interactions in the ultrahigh energy regime, far beyond the energies reached by colliders. In this article we study an observable that combines several advantages. It only makes use of the upward neutrino flux so that the Earth filters the atmospheric muons, and it is just weakly dependent on the initial astrophysical flux uncertainties.

  10. EarthCubed: Community Convergence and Communication

    Science.gov (United States)

    Ryan, J. C.; Black, R.; Davis, R.; Dick, C.; Lee, T.; Allison, M. L.

    2015-12-01

    What drives engagement across a diverse community with the common goal of creating a robust cyberinfrastructure for the geosciences? Which applications, social media venues and outreach mechanisms solicit the most valuable feedback? Of the dizzying toolkit available for community-building, which tools should receive time, attention and dedication? Finally, how does it all relate to better geoscience research? Research projects in the geosciences are rapidly becoming more interdisciplinary, requiring use of broader data-sets and a multitude of data-types in an effort to explain questions important to both the scientific community and the general public. Effective use of the data and tools available requires excellent community communication and engagement across disciplines, as well as a manner to easily obtain and access those data and tools. For over two years, the EarthCube project has sought to create the most active and engaged community possible, bringing together experts from all across the NSF GEO directorate and its many-faceted disciplines. Initial efforts focused on collecting insight and opinions at in-person "end-user workshops," and informal organization of interest groups and teams. Today, efforts feature an organizational structure with dedicated internal communication and outreach groups. The EarthCube Office has been largely responsible for coordination of these groups and the social media and Internet presence of the project to date, through the creation and curation of the EarthCube.org website, social media channels, live-streaming of meetings, and newsletters. Measures of the effectiveness of these efforts will be presented, to serve as potential reference and guidance for other projects seeking to grow their own communities. In addition, we will discuss how the Office's role in outreach and engagement has changed over the past year with the creation of the Engagement and Liaison Teams, and what it signifies for the Office's role in EarthCube

  11. Atmospheric neutrino oscillations with IceCube

    Energy Technology Data Exchange (ETDEWEB)

    Gross, Andreas [TU Muenchen (Germany); Collaboration: IceCube-Collaboration

    2012-07-01

    IceCube is a cubic kilometer scale neutrino telescope completed in December 2010 optimized for neutrino energies on the TeV to PeV scale. With its more densely instrumented DeepCore subarray in the center, the performance in the 10 GeV to 1 TeV energy range has been improved significantly. We present the status of an analysis using IceCube and DeepCore in the 79-string configuration which operated from May 2010 until May 2011. In this configuration it is expected to be sensitive to standard neutrino oscillations by atmospheric muon neutrino disappearance with a maximum effect around 30 GeV and for vertically upgoing events. An atmospheric neutrino event sample is extracted from DeepCore data in the energy range 15 GeV-150 GeV. Higher energetic atmospheric neutrinos detected by IceCube serve as a control sample for which no oscillation effects are expected.

  12. 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.

  13. 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 ...

  14. Cache-Conscious Data Cube Computation on a Modern Processor

    Institute of Scientific and Technical Information of China (English)

    Hua Luan; Xiao-Yong Du; Shan Wang

    2009-01-01

    Data cube computation is an important problem in the field of data warehousing and OLAP (online analytical processing). Although it has been studied extensively in the past, most of its algorithms are designed without considering CPU and cache behavior. In this paper, we first propose a cache-conscious cubing approach called CC-Cubing to efficiently compute data cubes on a modern processor. This method can enhance CPU and cache performances. It adopts an integrated depth-first and breadth-first partitioning order and partitions multiple dimensions simultaneously. The partitioning scheme improves the data spatial locality and increases the utilization of cache lines. Software prefetching techniques are then applied in the sorting phase to hide the expensive cache misses associated with data scans. In addition, a cache-aware method is used in CC-Cubing to switch the sort algorithm dynamically. Our performance study shows that CC-Cubing outperforms BUC, Star-Cubing and MM-Cubing in most cases. Then, in order to fully utilize an SMT (simultaneous multithreading) processor, we present a thread-based CC-Cubing-SMT method. This parallel method provides an improvement up to 27% for the single-threaded CC-Cubing algorithm.

  15. High frequency scattering from trihedral corner reflectors and other benchmark targets - SBR versus experiment. [Shooting and Bouncing Ray method

    Science.gov (United States)

    Baldauf, John; Lee, Shung-Wu; Lin, Luke; Jeng, Shyh-Kang; Scarborough, Steven M.; Yu, C. L.

    1991-01-01

    A general method for calculating the radar cross section (RCS) from a three-dimensional target is described. The target is first constructed by using a solid-geometry-modeling computer-aided design (CAD) package. Following the shooting and bouncing ray (SBR) method, a very dense grid of rays is launched from the incident direction toward the target. Each ray is traced according to the geometrical optics theory including the effect of ray tube divergence, polarization, and material reflection coefficient. At the point where the ray exits the target, a physical optics-type integration is performed to obtain the scattered far fields. This method is tested using several simple examples involving interaction among plates, cylinders, and spheres. The theoretical results are generally in good agreement with measured data.

  16. CubeSub - A CubeSat Based Submersible Testbed for Space Technology

    Science.gov (United States)

    Slettebo, Christian

    2016-01-01

    This report is a Master's Thesis in Aerospace Engineering, performed at the NASA Ames Research Center. It describes the development of the CubeSub, a submersible testbed compatible with the CubeSat form factor. The CubeSub will be used to mature technology and operational procedures to be used in space exploration, and possibly also as a tool for exploration of Earthly environments. CubeSats are carried as payloads, either containing technology to be tested or experiments and sensors for scientific use. The CubeSub is designed to be built up by modules, which can be assembled in different configurations to fulfill different needs. Each module is powered individually and intermodular communication is wireless, reducing the need for wiring. The inside of the hull is flooded with ambient water to simplify the interaction between payloads and surrounding environment. The overall shape is similar to that of a conventional AUV, slender and smooth. This is to make for a low drag, reduce the risk of snagging on surrounding objects and make it possible to deploy through an ice sheet via a narrow borehole. Rapid prototyping is utilized to a large extent, with full-scale prototypes being constructed through 3D-printing and with COTS (Commercial Off-The-Shelf) components. Arduino boards are used for control and internal communication. Modules required for basic operation have been designed, manufactured and tested. Each module is described with regards to its function, design and manufacturability. By performing tests in a pool it was found that the basic concept is sound and that future improvements include better controllability, course stability and waterproofing of electrical components. Further development is needed to make the CubeSub usable for its intended purposes. The largest gains are expected to be found by developing the software and improving controllability.

  17. 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.

  18. 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.

  19. 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...

  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. Composition: Around Corners (2006-08)

    DEFF Research Database (Denmark)

    Bergstrøm-Nielsen, Carl

    2010-01-01

    Around Corners is an open composition to be realised by improvising musicians. See more about my composition practise in the entry "Composition - General Introduction". Caution: streaming the sound/video files will in some cases only provide a few minutes' sample, or the visuals will not appear...... at all. Please DOWNLOAD them to see/hear them in full length! This work is licensed under a Creative Commons "by-nc" License. You may for non-commercial purposes use and distribute it, performance instructions as well as specially designated recordings, as long as the author(s) is (are) mentioned. Please...

  2. Corner Transfer Matrices and Quantum Affine Algebras

    CERN Document Server

    Foda, O E; Foda, Omar; Miwa, Tetsuji

    1992-01-01

    Let H be the corner-transfer-matrix Hamiltonian for the six-vertex model in the anti-ferroelectric regime. It acts on the infinite tensor product W = V . V . V ....., where is the 2-dimensional irreducible representation of the quantum affine sl(2). We observe that H is the derivation of quantum affine sl(2), and conjecture that the eigenvectors of H form the level-1 vacuum representation of quantum affine sl(2). We report on checks in support of our conjecture.

  3. Optimizing RDF Data Cubes for Efficient Processing of Analytical Queries

    DEFF Research Database (Denmark)

    Jakobsen, Kim Ahlstrøm; Andersen, Alex B.; Hose, Katja

    2015-01-01

    data warehouses and data cubes. Today, external data sources are essential for analytics and, as the Semantic Web gains popularity, more and more external sources are available in native RDF. With the recent SPARQL 1.1 standard, performing analytical queries over RDF data sources has finally become......In today’s data-driven world, analytical querying, typically based on the data cube concept, is the cornerstone of answering important business questions and making data-driven decisions. Traditionally, the underlying analytical data was mostly internal to the organization and stored in relational...... feasible. However, unlike their relational counterparts, RDF data cubes stores lack optimizations that enable fast querying. In this paper, we present an approach to optimizing RDF data cubes that is based on three novel cube patterns that optimize RDF data cubes, as well as associated algorithms...

  4. Neutrino astronomy with IceCube and AMANDA

    OpenAIRE

    Hill, Gary C; Collaboration, for the IceCube

    2006-01-01

    Since the early 1990s, the South Pole has been the site of the construction of the world's first under-ice Cherenkov neutrino telescopes - AMANDA and IceCube. The AMANDA detector was completed in 2000, and its successor IceCube, a kilometre scale neutrino detector, began construction in 2005. Completion of IceCube is scheduled for 2011. This paper will give an overview of the history, construction, latest physics results and potential of these detectors.

  5. 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.

  6. 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...

  7. 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 ...

  8. IceCube: A Cubic Kilometer Radiation Detector

    Energy Technology Data Exchange (ETDEWEB)

    IceCube Collaboration; Klein, Spencer R; Klein, S.R.

    2008-06-01

    IceCube is a 1 km{sup 3} neutrino detector now being built at the Amudsen-Scott South Pole Station. It consists of 4800 Digital Optical Modules (DOMs) which detect Cherenkov radiation from the charged particles produced in neutrino interactions. IceCube will observe astrophysical neutrinos with energies above about 100 GeV. IceCube will be able to separate {nu}{sub {mu}}, {nu}{sub t}, and {nu}{sub {tau}} interactions because of their different topologies. IceCube construction is currently 50% complete.

  9. Development of Novel Integrated Antennas for CubeSats

    Science.gov (United States)

    Jackson, David; Fink, Patrick W.; Martinez, Andres; Petro, Andrew

    2015-01-01

    The Development of Novel Integrated Antennas for CubeSats project is directed at the development of novel antennas for CubeSats to replace the bulky and obtrusive antennas (e.g., whip antennas) that are typically used. The integrated antennas will not require mechanical deployment and thus will allow future CubeSats to avoid potential mechanical problems and therefore improve mission reliability. Furthermore, the integrated antennas will have improved functionality and performance, such as circular polarization for improved link performance, compared with the conventional antennas currently used on CubeSats.

  10. Getting started with SQL Server 2012 cube development

    CERN Document Server

    Lidberg, Simon

    2013-01-01

    As a practical tutorial for Analysis Services, get started with developing cubes. ""Getting Started with SQL Server 2012 Cube Development"" walks you through the basics, working with SSAS to build cubes and get them up and running.Written for SQL Server developers who have not previously worked with Analysis Services. It is assumed that you have experience with relational databases, but no prior knowledge of cube development is required. You need SQL Server 2012 in order to follow along with the exercises in this book.

  11. Instant Microsoft SQL Server Analysis Services 2012 dimensions and cube

    CERN Document Server

    Acharya, Anurag

    2013-01-01

    Get to grips with a new technology, understand what it is and what it can do for you, and then get to work with the most important features and tasks. Written in a practical, friendly manner this book will take you through the journey from installing SQL Server to developing your first cubes.""Microsoft SQL Server Analysis Service 2012 Dimensions"" and Cube Starter is targeted at anyone who wants to get started with cube development in Microsoft SQL Server Analysis Services. Regardless of whether you are a SQL Server developer who knows nothing about cube development or SSAS or even OLAP, you

  12. 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...

  13. 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...

  14. Cube-in-cube hollow Cu9 S5 nanostructures with enhanced photocatalytic activities in solar H2 evolution.

    Science.gov (United States)

    Xu, Miao; Wang, Min; Ye, Tiannan; Liang, Na; Jin, Lun; Zai, Jiantao; Qian, Xuefeng

    2014-10-13

    Hydrogen produced from water under solar energy is an ideal clean energy source, and the efficiency of hydrogen production usually depends on the catalytic systems based on new compounds and/or a unique nanostructure. Herein, well-defined cube-in-cube hollow Cu9 S5 nanostructures have been successfully prepared with Cu2 O nanocubes and CS2 as precursors, and single-shell hollow Cu9 S5 nanocubes could be obtained by replacing CS2 with Na2 S. The formation mechanism of cube-in-cube hollow nanostructures has been proposed based on the Kirkendell effect and an outward self-assembly process. Further studies revealed that the cube-in-cube hollow Cu9 S5 nanostructures exhibited better photocatalytic activity toward solar H2 evolution and would be a promising photocatalyst in the solar hydrogen industry.

  15. Universal corner contributions to entanglement negativity

    Science.gov (United States)

    Kim, Keun-Young; Niu, Chao; Pang, Da-Wei

    2016-09-01

    It has been realised that corners in entangling surfaces can induce new universal contributions to the entanglement entropy and Rényi entropy. In this paper we study universal corner contributions to entanglement negativity in three- and four-dimensional CFTs using both field theory and holographic techniques. We focus on the quantity χ defined by the ratio of the universal part of the entanglement negativity over that of the entanglement entropy, which may characterise the amount of distillable entanglement. We find that for most of the examples χ takes bigger values for singular entangling regions, which may suggest increase in distillable entanglement. However, there also exist counterexamples where distillable entanglement decreases for singular surfaces. We also explore the behaviour of χ as the coupling varies and observe that for singular entangling surfaces, the amount of distillable entanglement is mostly largest for free theories, while counterexample exists for free Dirac fermion in three dimensions. For holographic CFTs described by higher derivative gravity, χ may increase or decrease, depending on the sign of the relevant parameters. Our results may reveal a more profound connection between geometry and distillable entanglement.

  16. Triadophilia: A Special Corner in the Landscape

    CERN Document Server

    Candelas, Philip; He, Yang-Hui; Szendroi, Balazs

    2007-01-01

    It is well known that there are a great many apparently consistent vacua of string theory. We draw attention to the fact that there appear to be very few Calabi--Yau manifolds with the Hodge numbers h^{11} and h^{21} both small. Of these, the case (h^{11}, h^{21})=(3,3) corresponds to a manifold on which a three generation heterotic model has recently been constructed. We point out also that there is a very close relation between this manifold and several familiar manifolds including the `three-generation' manifolds with \\chi=-6 that were found by Tian and Yau, and by Schimmrigk, during early investigations. It is an intriguing possibility that we may live in a naturally defined corner of the landscape. The location of these three generation models with respect to a corner of the landscape is so striking that we are led to consider the possibility of transitions between heterotic vacua. The possibility of these transitions, that we here refer to as transgressions, is an old idea that goes back to Witten. Here...

  17. Properties of the Ising magnet confined in a corner geometry

    Science.gov (United States)

    Albano, Ezequiel V.; de Virgiliis, Andres; Müller, Marcus; Binder, Kurt

    2007-10-01

    The properties of Ising square lattices with nearest neighbor ferromagnetic exchange confined in a corner geometry, are studied by means of Monte Carlo simulations. Free boundary conditions at which boundary magnetic fields ±h are applied, i.e., at the two boundary rows ending at the lower left corner a field +h acts, while at the two boundary rows ending at the upper right corner a field -h acts. For temperatures T less than the critical temperature T of the bulk, this boundary condition leads to the formation of two domains with opposite orientation of the magnetization direction, separated by an interface which for T larger than the filling transition temperature T(h) runs from the upper left corner to the lower right corner, while for Tinterface is localized either close to the lower left corner or close to the upper right corner. It is shown that for T=T(h) the magnetization profile m(z) in the z-direction normal to the interface simply is linear and the interfacial width scales as w∝L, while for T>T(h) it scales as w∝√{L}. The distribution P(ℓ) of the interface position ℓ (measured along the z-direction from the corners) decays exponentially for TT(h). Unlike the findings for critical wetting in the thin film geometry of the Ising model, the Monte Carlo results for corner wetting are in very good agreement with the theoretical predictions.

  18. Corner wetting transition in the two-dimensional Ising model

    Science.gov (United States)

    Lipowski, Adam

    1998-07-01

    We study the interfacial behavior of the two-dimensional Ising model at the corner of weakened bonds. Monte Carlo simulations results show that the interface is pinned to the corner at a lower temperature than a certain temperature Tcw at which it undergoes a corner wetting transition. The temperature Tcw is substantially lower than the temperature of the ordinary wetting transition with a line of weakened bonds. A solid-on-solid-like model is proposed, which provides a supplementary description of the corner wetting transition.

  19. Measuring the effect of rounding the corners of scattering structures

    Science.gov (United States)

    Markowskei, Audrey J.; Smith, Paul D.

    2017-05-01

    In studying acoustic or electromagnetic wave diffraction, the choice of an appropriate canonical structure to model the dominant features of a scattering scenario can be very illuminating. A common approach used when dealing with domains with corners is to round the corners, producing a smooth surface, eliminating the singularities introduced by the corners. In order to quantify the effect of corner rounding, this paper examines the diffraction from cylindrical scatterers which possess corners, that is, points at which the normal changes discontinuously. We develop a numerical method for the scattering of a plane wave normally incident on such cylindrical structures with soft, hard, or impedance loaded boundary conditions. We then examine the difference between various test structures with corners and with the corners rounded to assess the impact on near- and far-field scattering, as a function of the radius of curvature in the vicinity of the rounded corner point. We then examine the nature of the differences in the far field between the cornered and rounded scatterers as well as the effect on the differences as the frequency of the plane wave increases and obtain precise quantitative estimates for the rate of convergence of the maximum difference between the far-field solutions as the radius of curvature of the rounded scatterer approaches zero.

  20. Metal nanoparticles with sharp corners: Universal properties of plasmon resonances

    Science.gov (United States)

    Sturman, B.; Podivilov, E.; Gorkunov, M.

    2013-03-01

    We predict the simultaneous occurrence of two fundamental phenomena for metal nanoparticles possessing sharp corners with variable curvature: First, the main dipolar plasmonic mode experiences a strong red shift with increasing corner curvature; for large values of the curvature, the resonant frequency is controlled by the apex angle of the corner. Second, the split-off plasmonic mode experiences a strong localization at the corners. Altogether, this paves the way for the tailoring of metal nanostructures providing a wavelength-selective excitation of localized plasmons and a strong near-field enhancement of linear and nonlinear optical phenomena.

  1. 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

  2. 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.

  3. 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.

  4. Theoretical Implications of IceCube Neutrinos

    Science.gov (United States)

    Ahlers, Markus

    2014-03-01

    The IceCube Collaboration has recently found evidence for an astrophysical flux of neutrinos. The flux is consistent with an isotropic and equal-flavor E-2 power-law spectrum from 60 TeV to 2 PeV. There are also indications that the neutrino spectrum beyond 2 PeV requires a spectral break or cutoff. The origin of the IceCube excess is not known, but its multi-messenger context can already provide some theoretical orientation. For instance, the production of PeV neutrinos require hadronic interactions of cosmic rays (CRs) with energies of a few 10 PeV, extending into the poorly understood transition region between Galactic and extra-Galactic CRs. A local contribution to the neutrino flux from Galactic accelerators is hence feasible and could show up as arrival direction clustering towards Galactic structures. In this context, a possible association of the PeV neutrino sources with unidentified TeV gamma-ray sources, peculiar supernovae or the Fermi Bubbles has been speculated. In addition, a local hadronic neutrino production would predict an observable PeV gamma-ray flux. Spectral features of the neutrino flux, in particular a break or cutoff, serve as additional hints for candidate CR sources and astrophysical environments for neutrino production. Possible scenearios include starburst galaxies, low-luminosity gamma-ray bursts and the cores of active galactic nuclei. I will outline general theoretical implications of the IceCube excess and summarize various source candidates.

  5. Rank-3 Projections of a 4-Cube

    CERN Document Server

    Finch, Steven R

    2012-01-01

    The orthogonal projection of a 4-cube onto a uniform random 3-subspace in R^4 is a convex 3-polyhedron P with 14 vertices almost surely. Three numerical characteristics of P -- volume, surface area and mean width -- are studied. These quantities, along with the Euler characteristic, form a basis of the space of all additive continuous measures that are invariant under rigid motions in R^3. While computing statistics of {vl, ar, mw}, we encounter the generalized hypergeometric function, elliptic integrals and Catalan's constant. A new constant 7.1185587167... also arises and deserves further attention.

  6. Probing leptoquark production at IceCube

    CERN Document Server

    Anchordoqui, L A; Dumm, D G; Goldberg, H; Halzen, F; Anchordoqui, Luis A.; Canal, Carlos A. Garcia; Dumm, Daniel Gomez; Goldberg, Haim; Halzen, Francis

    2006-01-01

    We emphasize the inelasticity distribution of events detected at the IceCube neutrino telescope as an important tool for revealing new physics. This is possible because the unique energy resolution at this facility allows to separately assign the energy fractions for emergent muons and taus in neutrino interactions. As a particular example, we explore the possibility of probing second and third generation leptoquark parameter space (coupling and mass). We show that production of leptoquarks with masses \\agt 250 GeV and diagonal generation couplings of O(1) can be directly tested if the cosmic neutrino flux is at the Waxman-Bahcall level.

  7. 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

  8. Efficient video panoramic image stitching based on an improved selection of Harris corners and a multiple-constraint corner matching.

    Directory of Open Access Journals (Sweden)

    Minchen Zhu

    Full Text Available Video panoramic image stitching is extremely time-consuming among other challenges. We present a new algorithm: (i Improved, self-adaptive selection of Harris corners. The successful stitching relies heavily on the accuracy of corner selection. We fragment each image into numerous regions and select corners within each region according to the normalized variance of region grayscales. Such a selection is self-adaptive and guarantees that corners are distributed proportional to region texture information. The possible clustering of corners is also avoided. (ii Multiple-constraint corner matching. The traditional Random Sample Consensus (RANSAC algorithm is inefficient, especially when handling a large number of images with similar features. We filter out many inappropriate corners according to their position information, and then generate candidate matching pairs based on grayscales of adjacent regions around corners. Finally we apply multiple constraints on every two pairs to remove incorrectly matched pairs. By a significantly reduced number of iterations needed in RANSAC, the stitching can be performed in a much more efficient manner. Experiments demonstrate that (i our corner matching is four times faster than normalized cross-correlation function (NCC rough match in RANSAC and (ii generated panoramas feature a smooth transition in overlapping image areas and satisfy real-time human visual requirements.

  9. Theoretical Aspects of Target Classification. Lecture Series of the Electromagnetic Wave Propagation Panel and the Consultant and Exchange Programme Held in Rome, Italy on 29-30 June 1987; Neuiberg, Germany on 2-3 July 1987 and Noresund, Norway on 6-7 July 1987.

    Science.gov (United States)

    1987-06-01

    PA-:-EFI IN Y-: .Z L 5& E Figure 22. Radar cross section of an ogive with a circular duct 2-20 F-16 LIE DFAWIMI AN TI NNA F-16 COMPUTER 22EL VFONT...and cone 13., 91, cube [8, 91, cube with additional shadowing surfaces [9, 101, trihedral corner reflector [111. In the following the PO procedure is...d) circular cylinder terminated by a cne ana a half-sphere, i = 3 0 0 ... 130o, lo mn 80 80’ 250 80 e) cube, 19.39 mm f) trihedral corner reflector

  10. Atmospheric Neutrino Oscillations in IceCube

    Energy Technology Data Exchange (ETDEWEB)

    Groß, A. [Technische Universität München, D-85748 Garching (Germany)

    2013-04-15

    We present the results of an analysis of data collected by IceCube/DeepCore in 2010-2011 resulting in the first significant detection of neutrino oscillations in a high-energy neutrino telescope. A low-energy muon neutrino sample (20–100GeV) containing the oscillation signal was extracted from data collected by DeepCore. A high-energy muon neutrino sample (100GeV–10TeV) was extracted from IceCube data in order to constrain the systematic uncertainties. The non-oscillation hypothesis was rejected with more than 5σ. We fitted the oscillation parameters Δm{sub 23}{sup 2} and sin{sup 2}2θ{sub 23} to these data samples. In a 2-flavor formalism we find Δm{sub 23}{sup 2}=(2.5±0.6)⋅10{sup −3}eV{sup 2} and sin{sup 2}2θ{sub 23}>0.92 while maximum mixing is favored. These results are in good agreement with the world average values.

  11. Invited Article: miniTimeCube

    Science.gov (United States)

    Li, V. A.; Dorrill, R.; Duvall, M. J.; Koblanski, J.; Negrashov, S.; Sakai, M.; Wipperfurth, S. A.; Engel, K.; Jocher, G. R.; Learned, J. G.; Macchiarulo, L.; Matsuno, S.; McDonough, W. F.; Mumm, H. P.; Murillo, J.; Nishimura, K.; Rosen, M.; Usman, S. M.; Varner, G. S.

    2016-02-01

    We present the development of the miniTimeCube (mTC), a novel compact neutrino detector. The mTC is a multipurpose detector, aiming to detect not only neutrinos but also fast/thermal neutrons. Potential applications include the counterproliferation of nuclear materials and the investigation of antineutrino short-baseline effects. The mTC is a plastic 0.2% 10B-doped scintillator (13 cm)3 cube surrounded by 24 Micro-Channel Plate (MCP) photon detectors, each with an 8 × 8 anode totaling 1536 individual channels/pixels viewing the scintillator. It uses custom-made electronics modules which mount on top of the MCPs, making our detector compact and able to both distinguish different types of events and reject noise in real time. The detector is currently deployed and being tested at the National Institute of Standards and Technology Center for Neutron Research nuclear reactor (20 MWth) in Gaithersburg MD. A shield for further tests is being constructed, and calibration and upgrades are ongoing. The mTC's improved spatiotemporal resolution will allow for determination of incident particle directions beyond previous capabilities.

  12. Invited Article: miniTimeCube

    CERN Document Server

    Li, V A; Duvall, M J; Koblanski, J; Negrashov, S; Sakai, M; Wipperfurth, S A; Engel, K; Jocher, G R; Learned, J G; Macchiarulo, L; Matsuno, S; McDonough, W F; Mumm, H P; Murillo, J; Nishimura, K; Rosen, M; Usman, S M; Varner, G S

    2016-01-01

    We present the development of the miniTimeCube (mTC), a novel compact neutrino detector. The mTC is a multipurpose detector, aiming to detect not only neutrinos but also fast/thermal neutrons. Potential applications include the counterproliferation of nuclear materials and the investigation of antineutrino short-baseline effects. The mTC is a plastic 0.2% $^{10}$B - doped scintillator (13 cm)$^3$ cube surrounded by 24 Micro-Channel Plate (MCP) photon detectors, each with an $8\\times8$ anode totaling 1536 individual channels/pixels viewing the scintillator. It uses custom-made electronics modules which mount on top of the MCPs, making our detector compact and able to both distinguish different types of events and reject noise in real time. The detector is currently deployed and being tested at the National Institute of Standards and Technology (NIST) Center for Neutron Research (NCNR) nuclear reactor (20 MW$_\\mathrm{th}$) in Gaithersburg, MD. A shield for further tests is being constructed, and calibration and...

  13. On the IceCube spectral anomaly

    CERN Document Server

    Palladino, Andrea; Vissani, Francesco

    2016-01-01

    Recently it was noted that different IceCube datasets are not consistent with the same power law spectrum of the cosmic neutrinos: this is the IceCube spectral anomaly, that suggests that they observe a multicomponent spectrum. In this work, the main possibilities to enhance the description in terms of a single extragalactic neutrino component are examined. The hypothesis of a sizable contribution of Galactic high-energy neutrino events distributed as $E^{-2.7}$ [ApJ 826, 185 (2016)] is critically analyzed and its natural generalization is considered. The stability of the expectations is studied by introducing free parameters, motivated by theoretical considerations and observational facts. The upgraded model here examined has 1)~a Galactic component with different normalization and shape $E^{- 2.4}$; 2)~an extragalactic neutrino spectrum based on new data; 3)~a non-zero prompt component of atmospheric neutrinos. The two key predictions of the model concern the `high-energy starting events' collected from the...

  14. On the IceCube spectral anomaly

    Science.gov (United States)

    Palladino, Andrea; Spurio, Maurizio; Vissani, Francesco

    2016-12-01

    Recently it was noted that different IceCube datasets are not consistent with the same power law spectrum of the cosmic neutrinos: this is the IceCube spectral anomaly, that suggests that they observe a multicomponent spectrum. In this work, the main possibilities to enhance the description in terms of a single extragalactic neutrino component are examined. The hypothesis of a sizable contribution of Galactic high-energy neutrino events distributed as E‑2.7 [Astrophys. J. 826 (2016) 185] is critically analyzed and its natural generalization is considered. The stability of the expectations is studied by introducing free parameters, motivated by theoretical considerations and observational facts. The upgraded model here examined has 1) a Galactic component with different normalization and shape E‑2.4 2) an extragalactic neutrino spectrum based on new data; 3) a non-zero prompt component of atmospheric neutrinos. The two key predictions of the model concern the `high-energy starting events' collected from the Southern sky. The Galactic component produces a softer spectrum and a testable angular anisotropy. A second, radically different class of models, where the second component is instead isotropic, plausibly extragalactic and with a relatively soft spectrum, is disfavored instead by existing observations of muon neutrinos from the Northern sky and below few 100 TeV.

  15. CubeSat quantum communications mission

    Energy Technology Data Exchange (ETDEWEB)

    Oi, Daniel K.L. [University of Strathclyde, SUPA Department of Physics, Glasgow (United Kingdom); University of Strathclyde, Strathclyde Space Institute, Glasgow (United Kingdom); Ling, Alex [National University of Singapore, Centre for Quantum Technologies, Singapore (Singapore); National University of Singapore, Dept. of Physics, Singapore (Singapore); Vallone, Giuseppe; Villoresi, Paolo [Universita degli Studi di Padova, Dipartimento di Ingegneria dell' Informazione, Padova (Italy); Greenland, Steve; Kerr, Emma [University of Strathclyde, Advanced Space Concepts Laboratory, Mechanical and Aerospace Engineering, Glasgow (United Kingdom); Macdonald, Malcolm [Technology and Innovation Centre, Scottish Centre of Excellence in Satellite Applications, Glasgow (United Kingdom); Weinfurter, Harald [Ludwig-Maximilians-Universitaet, Department fuer Physik, Munich (Germany); Kuiper, Hans [Delft University of Technology, Space Systems Engineering, Aerospace Engineering, Delft (Netherlands); Charbon, Edoardo [AQUA, EPFL, Lausanne (Switzerland); Delft University of Technology, Delft (Netherlands); Ursin, Rupert [Vienna Austrian Academy of Sciences, Institute for Quantum Optics and Quantum Information, Vienna (Austria)

    2017-12-15

    Quantum communication is a prime space technology application and offers near-term possibilities for long-distance quantum key distribution (QKD) and experimental tests of quantum entanglement. However, there exists considerable developmental risks and subsequent costs and time required to raise the technological readiness level of terrestrial quantum technologies and to adapt them for space operations. The small-space revolution is a promising route by which synergistic advances in miniaturization of both satellite systems and quantum technologies can be combined to leap-frog conventional space systems development. Here, we outline a recent proposal to perform orbit-to-ground transmission of entanglement and QKD using a CubeSat platform deployed from the International Space Station (ISS). This ambitious mission exploits advances in nanosatellite attitude determination and control systems (ADCS), miniaturised target acquisition and tracking sensors, compact and robust sources of single and entangled photons, and high-speed classical communications systems, all to be incorporated within a 10 kg 6 litre mass-volume envelope. The CubeSat Quantum Communications Mission (CQuCoM) would be a pathfinder for advanced nanosatellite payloads and operations, and would establish the basis for a constellation of low-Earth orbit trusted-nodes for QKD service provision. (orig.)

  16. 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...

  17. Cornering diphoton resonance models at the LHC

    CERN Document Server

    Backović, Mihailo; Mariotti, Alberto; Sessolo, Enrico Maria; Spannowsky, Michael

    2016-01-01

    We explore the ability of the high luminosity LHC to test models which can explain the 750 GeV diphoton excess. We focus on a wide class of models where a 750 GeV singlet scalar couples to Standard Model gauge bosons and quarks, as well as dark matter. Including both gluon and photon fusion production mechanisms, we show that LHC searches in channels correlated with the diphoton signal will be able to probe wide classes of diphoton models with $\\mathcal{L} \\sim 3000\\, \\text{fb}^{-1}$ of data. Furthermore, models in which the scalar is a portal to the dark sector can be cornered with as little as $\\mathcal{L} \\sim 30\\, \\text{fb}^{-1}$.

  18. Cornering diphoton resonance models at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Backović, Mihailo [Center for Cosmology, Particle Physics and Phenomenology (CP3),Universite Catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Kulkarni, Suchita [Institute of High Energy Physics, Austrian Academy of Sciences,Nikolsdorfergasse 18, 1050 Vienna (Austria); Mariotti, Alberto [Theoretische Natuurkunde and IIHE/ELEM, Vrije Universiteit Brussel,and International Solvay Institutes, Pleinlaan 2, B-1050 Brussels (Belgium); Sessolo, Enrico Maria [National Centre for Nuclear Research,Hoża 69, 00-681 Warsaw (Poland); Spannowsky, Michael [Institute for Particle Physics Phenomenology, Department of Physics,Durham University, Durham, DH13LE (United Kingdom)

    2016-08-02

    We explore the ability of the high luminosity LHC to test models which can explain the 750 GeV diphoton excess. We focus on a wide class of models where a 750 GeV singlet scalar couples to Standard Model gauge bosons and quarks, as well as dark matter. Including both gluon and photon fusion production mechanisms, we show that LHC searches in channels correlated with the diphoton signal will be able to probe wide classes of diphoton models with L∼3000 fb{sup −1} of data. Furthermore, models in which the scalar is a portal to the dark sector can be cornered with as little as L∼30 fb{sup −1}.

  19. Colloidal cubes for the enhanced degradation of organic dyes

    NARCIS (Netherlands)

    Castillo, Sonja I R; Pompe, Cornelia E.; Van Mourik, Jim; Verbart, David M A; Thies - Weesie, Dominique; De Jongh, Petra E.; Philipse, Albert P.

    2014-01-01

    The shape of cubic silica colloids is exploited to form close-packed structures, whereas the hollow core of the cubes may host functional substances. A proof-of-principle of this approach is presented for iron oxide particles (hematite, α-Fe2O3) confined inside silica cubes that display the ability

  20. Diseño y estudio de “Corner-reflectors” para sistemas radar utilizando la herramienta software POFACETS

    OpenAIRE

    Corredor Pedrero, Antonio

    2016-01-01

    El Trabajo Fin de Grado se centrará en el diseño y estudio de Corner-Reflectors (CR) de aluminio en forma de triedro para su posterior uso en procesos de calibración y georreferenciación de sistemas SAR (SyntheticAperture Radar). El estudio del diseño se realizará analizando la RCS (Radar Cross Section) producida por los cambios en los parámetros de diseño del CR. Las características de diseño que se estudiarán son la longitud de las aristas, ángulo de canteo de las aristas, radio del orifici...

  1. 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

  2. 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.

  3. 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.

  4. Effect of precipitation on the evolution of cube recrystallization texture

    Energy Technology Data Exchange (ETDEWEB)

    Benum, S. [Hydro Aluminium, Haavik (Norway). R and D Materials Technology; Nes, E. [Norwegian Univ. of Science and Technology, Trondheim (Norway). Dept. of Metallurgy

    1997-11-01

    A study of the evolution of recrystallized structure and texture in the surface of a cold rolled twin roll cast AlFeSi alloy is presented. Annealing of such alloys often results in an abnormally coarse grained recrystallized surface structure with a strong cube texture. The evolution of this structure depends on the annealing procedures, that is, the precipitation state. Increased amounts of precipitating particles increase the grain size and the fraction of cube texture. The oriented growth theory does not offer any plausible interpretation of this precipitation effect. A recrystallization model that incorporates the differences in Zener drag between different annealing procedures has shown that the evolution of a strong cube texture and coarse grains is the result of a preferential nucleation of cube oriented grains. Precipitation increases the critical nucleation diameter and the resulting grain size. Cube oriented subgrains have a size advantage compared to other potential nucleation sites and are therefore not so affected by precipitation.

  5. Intervjuu James Corneriga = Interview with James Corner / James Corner ; interv. Andres Sevtshuk

    Index Scriptorium Estoniae

    Corner, James

    2006-01-01

    Büroo Field Operations maastikuarhitekt ning Pennsylvania Ülikooli maastikuarhitektuuri osakonna juhataja James Corner oma büroost, maastikust kui "instrumendist", postindustriaalsete aladega seotud projektidest (New Yorgi High Line'i muutmine pargiks ja promenaadiks), tööst suuremahuliste maastikega (Fresh Kills'i soo, endise prügila muutmine pargialaks), maastikuarhitektuurist ja linnakujundusest (maastiku urbanism), õpetamise tähtsusest oma töös ja maastikuarhitektuuri ideede arendamisel. Bibl. lk. 24

  6. Intervjuu James Corneriga = Interview with James Corner / James Corner ; interv. Andres Sevtshuk

    Index Scriptorium Estoniae

    Corner, James

    2006-01-01

    Büroo Field Operations maastikuarhitekt ning Pennsylvania Ülikooli maastikuarhitektuuri osakonna juhataja James Corner oma büroost, maastikust kui "instrumendist", postindustriaalsete aladega seotud projektidest (New Yorgi High Line'i muutmine pargiks ja promenaadiks), tööst suuremahuliste maastikega (Fresh Kills'i soo, endise prügila muutmine pargialaks), maastikuarhitektuurist ja linnakujundusest (maastiku urbanism), õpetamise tähtsusest oma töös ja maastikuarhitektuuri ideede arendamisel. Bibl. lk. 24

  7. Achieving Science with CubeSats: Thinking Inside the Box

    Science.gov (United States)

    Zurbuchen, Thomas H.; Lal, Bhavya

    2017-01-01

    We present the results of a study conducted by the National Academies of Sciences, Engineering, and Medicine. The study focused on the scientific potential and technological promise of CubeSats. We will first review the growth of the CubeSat platform from an education-focused technology toward a platform of importance for technology development, science, and commercial use, both in the United States and internationally. The use has especially exploded in recent years. For example, of the over 400 CubeSats launched since 2000, more than 80% of all science-focused ones have been launched just in the past four years. Similarly, more than 80% of peer-reviewed papers describing new science based on CubeSat data have been published in the past five years.We will then assess the technological and science promise of CubeSats across space science disciplines, and discuss a subset of priority science goals that can be achieved given the current state of CubeSat capabilities. Many of these goals address targeted science, often in coordination with other spacecraft, or by using sacrificial or high-risk orbits that lead to the demise of the satellite after critical data have been collected. Other goals relate to the use of CubeSats as constellations or swarms, deploying tens to hundreds of CubeSats that function as one distributed array of measurements.Finally, we will summarize our conclusions and recommendations from this study; especially those focused on nearterm investment that could improve the capabilities of CubeSats toward increased science and technological return and enable the science communities’ use of CubeSats.

  8. 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

  9. The Larger Bound on the Domination Number of Fibonacci Cubes and Lucas Cubes

    Directory of Open Access Journals (Sweden)

    Shengzhang Ren

    2014-01-01

    Full Text Available Let Γn and Λn be the n-dimensional Fibonacci cube and Lucas cube, respectively. Denote by Γ[un,k,z] the subgraph of Γn induced by the end-vertex un,k,z that has no up-neighbor. In this paper, the number of end-vertices and domination number γ of Γn and Λn are studied. The formula of calculating the number of end-vertices is given and it is proved that γ(Γ[un,k,z]≤2k-1+1. Using these results, the larger bound on the domination number γ of Γn and Λn is determined.

  10. CubeSats for Astrophysics: The Current Perspective

    Science.gov (United States)

    Ardila, David R.; Shkolnik, Evgenya; Gorjian, Varoujan

    2017-01-01

    Cubesats are small satellites built to multiples of 1U (1000 cm3). The 2016 NRC Report “Achieving Science with CubeSats” indicates that between 2013 and 2018 NASA and NSF sponsored 104 CubeSats. Of those, only one is devoted to astrophysics: HaloSat (PI: P. Kaaret), a 6U CubeSat with an X-ray payload to study the hot galactic halo.Despite this paucity of missions, CubeSats have a lot of potential for astrophysics. To assess the science landscape that a CubeSat astrophysics mission may occupy, we consider the following parameters:1-Wavelength: CubeSats are not competitive in the visible, unless the application (e.g. high precision photometry) is difficult to do from the ground. Thermal IR science is limited by the lack of low-power miniaturized cryocoolers and by the large number of infrared astrophysical missions launched or planned. In the UV, advances in δ-doping processes result in larger sensitivity with smaller apertures. Commercial X-ray detectors also allow for competitive science.2-Survey vs. Pointed observations: All-sky surveys have been done at most wavelengths from X-rays to Far-IR and CubeSats will not be able to compete in sensitivity with them. CubeSat science should then center on specific objects or object classes. Due to poor attitude control, unresolved photometry is scientifically more promising that extended imaging.3-Single-epoch vs. time domain: CubeSat apertures cannot compete in sensitivity with big satellites when doing single-epoch observations. However, time-domain astrophysics is an area in which CubeSats can provide very valuable science return.Technologically, CubeSat astrophysics is limited by:1-Lack of large apertures: The largest aperture CubeSat launched is ~10 cm, although deployable apertures as large as 20 cm could be fitted to 6U buses.2-Poor attitude control: State-of-the-art systems have demonstrated jitter of ~10” on timescales of seconds. Jitter imposes limits on image quality and, coupled with detector errors

  11. Near Earth Network (NEN) CubeSat Communications

    Science.gov (United States)

    Schaire, Scott

    2017-01-01

    The NASA Near Earth Network (NEN) consists of globally distributed tracking stations, including NASA, commercial, and partner ground stations, that are strategically located to maximize the coverage provided to a variety of orbital and suborbital missions, including those in LEO (Low Earth Orbit), GEO (Geosynchronous Earth Orbit), HEO (Highly Elliptical Orbit), lunar and L1-L2 orbits. The NEN's future mission set includes and will continue to include CubeSat missions. The first NEN-supported CubeSat mission will be the Cubesat Proximity Operations Demonstration (CPOD) launching into LEO in 2017. The majority of the CubeSat missions destined to fly on EM-1, launching in late 2018, many in a lunar orbit, will communicate with ground-based stations via X-band and will utilize the NASA Jet Propulsion Laboratory (JPL)-developed IRIS (Satellite Communication for Air Traffic Management) radio. The NEN recognizes the important role CubeSats are beginning to play in carrying out NASAs mission and is therefore investigating the modifications needed to provide IRIS radio compatibility. With modification, the NEN could potentially expand support to the EM-1 (Exploration Mission-1) lunar CubeSats. The NEN could begin providing significant coverage to lunar CubeSat missions utilizing three to four of the NEN's mid-latitude sites. This coverage would supplement coverage provided by the JPL Deep Space Network (DSN). The NEN, with smaller apertures than DSN, provides the benefit of a larger beamwidth that could be beneficial in the event of uncertain ephemeris data. In order to realize these benefits the NEN would need to upgrade stations targeted based on coverage ability and current configuration ease of upgrade, to ensure compatibility with the IRIS radio. In addition, the NEN is working with CubeSat radio developers to ensure NEN compatibility with alternative CubeSat radios for Lunar and L1-L2 CubeSats. The NEN has provided NEN compatibility requirements to several radio

  12. 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.

  13. 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...

  14. 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.

  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. 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

  18. 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.

  19. IceCube: CubeSat 883-GHz Radiometry for Future Ice Cloud Remote Sensing

    Science.gov (United States)

    Wu, Dongliang; Esper, Jaime; Ehsan, Negar; Johnson, Thomas; Mast, William; Piepmeier, Jeffery R.; Racette, Paul E.

    2015-01-01

    Ice clouds play a key role in the Earth's radiation budget, mostly through their strong regulation of infrared radiation exchange. Accurate observations of global cloud ice and its distribution have been a challenge from space, and require good instrument sensitivities to both cloud mass and microphysical properties. Despite great advances from recent spaceborne radar and passive sensors, uncertainty of current ice water path (IWP) measurements is still not better than a factor of 2. Submillimeter (submm) wave remote sensing offers great potential for improving cloud ice measurements, with simultaneous retrievals of cloud ice and its microphysical properties. The IceCube project is to enable this cloud ice remote sensing capability in future missions, by raising 874-GHz receiver technology TRL from 5 to 7 in a spaceflight demonstration on 3-U CubeSat in a low Earth orbit (LEO) environment. The NASAs Goddard Space Flight Center (GSFC) is partnering with Virginia Diodes Inc (VDI) on the 874-GHz receiver through its Vector Network Analyzer (VNA) extender module product line, to develop an instrument with precision of 0.2 K over 1-second integration and accuracy of 2.0 K or better. IceCube is scheduled to launch to and subsequent release from the International Space Station (ISS) in mid-2016 for nominal operation of 28 plus days. We will present the updated design of the payload and spacecraft systems, as well as the operation concept. We will also show the simulated 874-GHz radiances from the ISS orbits and cloud scattering signals as expected for the IceCube cloud radiometer.

  20. 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.

  1. Modified MIMO Cube for Enhanced Channel Capacity

    Directory of Open Access Journals (Sweden)

    Lajos Nagy

    2012-01-01

    Full Text Available This paper deals with the optimization of MIMO antenna elements' position in modified MIMO cube for getting maximal channel capacity in indoor environment. The dependence of the channel capacity on the antenna orientation was analyzed by simulations. We have also examined the effect of the frequency dependence of the antenna system (in case of conjugate matching and nonconjugate matching for the channel capacity. Based on the simulation results in the created and measured antenna system, the antennas were at a right angle to each other. At the two chosen different structures, we measured the antenna parameters and the channel capacity. In this paper, we present the results of the measurements which clearly confirm our simulations. We will point out the differences between the two antenna structures.

  2. 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...

  3. 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

  4. 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...

  5. A SiPM-based isotropic-3D PET detector X'tal cube with a three-dimensional array of 1 mm(3) crystals.

    Science.gov (United States)

    Yamaya, Taiga; Mitsuhashi, Takayuki; Matsumoto, Takahiro; Inadama, Naoko; Nishikido, Fumihiko; Yoshida, Eiji; Murayama, Hideo; Kawai, Hideyuki; Suga, Mikio; Watanabe, Mitsuo

    2011-11-07

    We are developing a novel, general purpose isotropic-3D PET detector X'tal cube which has high spatial resolution in all three dimensions. The research challenge for this detector is implementing effective detection of scintillation photons by covering six faces of a segmented crystal block with silicon photomultipliers (SiPMs). In this paper, we developed the second prototype of the X'tal cube for a proof-of-concept. We aimed at realizing an ultimate detector with 1.0 mm(3) cubic crystals, in contrast to our previous development using 3.0 mm(3) cubic crystals. The crystal block was composed of a 16 × 16 × 16 array of lutetium gadolinium oxyorthosilicate (LGSO) crystals 0.993 × 0.993 × 0.993 mm(3) in size. The crystals were optically glued together without inserting any reflector inside and 96 multi-pixel photon counters (MPPCs, S10931-50P, i.e. six faces each with a 4 × 4 array of MPPCs), each having a sensitive area of 3.0 × 3.0 mm(2), were optically coupled to the surfaces of the crystal block. Almost all 4096 crystals were identified through Anger-type calculation due to the finely adjusted reflector sheets inserted between the crystal block and light guides. The reflector sheets, which formed a belt of 0.5 mm width, were placed to cover half of the crystals of the second rows from the edges in order to improve identification performance of the crystals near the edges. Energy resolution of 12.7% was obtained at 511 keV with almost uniform light output for all crystal segments thanks to the effective detection of the scintillation photons.

  6. 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.

  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. 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. 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.

  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. Corner Sort for Pareto-Based Many-Objective Optimization.

    Science.gov (United States)

    Wang, Handing; Yao, Xin

    2014-01-01

    Nondominated sorting plays an important role in Pareto-based multiobjective evolutionary algorithms (MOEAs). When faced with many-objective optimization problems multiobjective optimization problems (MOPs) with more than three objectives, the number of comparisons needed in nondominated sorting becomes very large. In view of this, a new corner sort is proposed in this paper. Corner sort first adopts a fast and simple method to obtain a nondominated solution from the corner solutions, and then uses the nondominated solution to ignore the solutions dominated by it to save comparisons. Obtaining the nondominated solutions requires much fewer objective comparisons in corner sort. In order to evaluate its performance, several state-of-the-art nondominated sorts are compared with our corner sort on three kinds of artificial solution sets of MOPs and the solution sets generated from MOEAs on benchmark problems. On one hand, the experiments on artificial solution sets show the performance on the solution sets with different distributions. On the other hand, the experiments on the solution sets generated from MOEAs show the influence that different sorts bring to MOEAs. The results show that corner sort performs well, especially on many-objective optimization problems. Corner sort uses fewer comparisons than others.

  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. EarthCube - Results of Test Governance in Geoscience Cyberinfrastructure

    Science.gov (United States)

    Davis, R.; Allison, M. L.; Keane, C. M.; Robinson, E.

    2016-12-01

    In September 2016, the EarthCube Test Enterprise Governance Project completed its three-year long process to engage the community and test a demonstration governing organization with the goal of facilitating a community-led process on designing and developing a geoscience cyberinfrastructure to transform geoscience research. The EarthCube initiative is making an important transition from creating a coherent community towards adoption and implemention of technologies that can serve scientists working in and across many domains. The emerging concept of a "system of systems" approach to cyberinfrastructure architecture is a critical concept in the EarthCube program, but has not been fully defined. Recommendations from an NSF-appointed Advisory Committee include: a. developing a succinct definition of EarthCube; b. changing the community-elected governance approach towards structured rather than consensus-driven decision-making; c. restructuring the process to articulate program solicitations; and d. producing an effective implementation roadmap. These are seen as prerequisites to adoption of best practices, system concepts, and evolving to a production track. The EarthCube governing body is preparing responses to the Advisory Committee findings and recommendations with a target delivery date of late 2016 but broader involvement may be warranted. We conclude that there is ample justification to continue evolving to a governance framework that facilitates convergence on a system architecture that guides EarthCube activities and plays an influential role in making operational the EarthCube vision of cyberinfrastructure for the geosciences. There is widespread community expectation for support of a multiyear EarthCube governing effort to put into practice the science, technical, and organizational plans that are continuing to emerge. However, the active participants in EarthCube represent a small sub-set of the larger population of geoscientists.

  14. Capillary surface discontinuities above reentrant corners

    Science.gov (United States)

    Korevaar, H. J.

    1982-01-01

    A particular configuration of a vertical capillary tube for which S is the equilibrium interface between two fluids in the presence of a downward pointing gravitational field was investigated. S is the graph a function u whose domain is the (horizontal) cross section gamma of the tube. The mean curvature of S is proportional to its height above a fixed reference plane and lambda is a prescribed constant and may be taken between zero and pi/2. Domains gamma for which us is a bounded function but does not extend continuously to d gamma are sought. Simple domains are found and the behavior of u in those domains is studied. An important comparison principle that has been used in the literature to derive many of the results in capillarity is reviewed. It allows one to deduce the approximate shape of a capillary surface by constructing comparison surfaces with mean curvature and contact angle close to those of the (unknown) solution surface. In the context of nonparametric problems the comparison principle leads to height estimates above and below for the function u. An example from the literature where these height estimates have been used successfully is described. The promised domains for which the bounded u does not extend continuously to the boundary are constructed. The point on the boundary at which u has a jump discontinuity will be the vertext of a re-entrant corner having any interior angle theta pi. Using the comparison principle the behavior of u near this point is studied.

  15. QbX - The CubeSat Experiment

    OpenAIRE

    Arnold, Stephen; Armstrong, James; Person, Clark; Tietz, Michael

    2012-01-01

    The Naval Research Laboratory (NRL) launched 2 QbX CubeSats from Cape Canaveral Air Force Station on December 8, 2010 as secondary payloads aboard SpaceX’s Falcon 9 launch vehicle, leveraging the flight opportunity provided by the first COTS Demo Flight of SpaceX’s Dragon Module. This paper will describe the development of the QbX CubeSats, present measured flight data, and evaluate the overall mission performance of the QbX CubeSats.

  16. New Formula for Stability of Cube Armoured Roundheads

    DEFF Research Database (Denmark)

    Maciñeira, Enrique; Burcharth, Hans F.

    2009-01-01

    The paper presents a new formula for the stability of cube armoured roundheads. The formula is based on physical model tests in Aalborg University which both long crested and short crested waves of different wave steepness were used. The slope of the radius of the head were varied in order...... to explore the influence of the geometry on the armour stability. Besides cubes with mass density 2.4 t/m3, cubes with mass density 2.80 t/m3 were used in order to include the effect of mass density in the formula. The damage predictions given by the formula have been compared with prototype hand...

  17. 3D Printing the Complete CubeSat

    Science.gov (United States)

    Kief, Craig

    2015-01-01

    The 3D Printing the Complete CubeSat project is designed to advance the state-of-the-art in 3D printing for CubeSat applications. Printing in 3D has the potential to increase reliability, reduce design iteration time and provide greater design flexibility in the areas of radiation mitigation, communications, propulsion, and wiring, among others. This project is investigating the possibility of including propulsion systems into the design of printed CubeSat components. One such concept, an embedded micro pulsed plasma thruster (mPPT), could provide auxiliary reaction control propulsion for a spacecraft as a means to desaturate momentum wheels.

  18. Wall-Corner Classification Using Sonar: A New Approach Based on Geometric Features

    Directory of Open Access Journals (Sweden)

    Ginés Benet

    2010-11-01

    Full Text Available Ultrasonic signals coming from rotary sonar sensors in a robot gives us several features about the environment. This enables us to locate and classify the objects in the scenario of the robot. Each object and reflector produces a series of peaks in the amplitude of the signal. The radial and angular position of the sonar sensor gives information about location and their amplitudes offer information about the nature of the surface. Early works showed that the amplitude can be modeled and used to classify objects with very good results at short distances—80% average success in classifying both walls and corners at distances less than 1.5 m. In this paper, a new set of geometric features derived from the amplitude analysis of the echo is presented. These features constitute a set of characteristics that can be used to improve the results of classification at distances from 1.5 m to 4 m. Also, a comparative study on classification algorithms widely used in pattern recognition techniques has been carried out for sensor distances ranging between 0.5 to 4 m, and with incidence angles ranging between 20º to 70º. Experimental results show an enhancement on the success in classification rates when these geometric features are considered.

  19. Wall-corner classification using sonar: a new approach based on geometric features.

    Science.gov (United States)

    Martínez, Milagros; Benet, Ginés

    2010-01-01

    Ultrasonic signals coming from rotary sonar sensors in a robot gives us several features about the environment. This enables us to locate and classify the objects in the scenario of the robot. Each object and reflector produces a series of peaks in the amplitude of the signal. The radial and angular position of the sonar sensor gives information about location and their amplitudes offer information about the nature of the surface. Early works showed that the amplitude can be modeled and used to classify objects with very good results at short distances-80% average success in classifying both walls and corners at distances less than 1.5 m. In this paper, a new set of geometric features derived from the amplitude analysis of the echo is presented. These features constitute a set of characteristics that can be used to improve the results of classification at distances from 1.5 m to 4 m. Also, a comparative study on classification algorithms widely used in pattern recognition techniques has been carried out for sensor distances ranging between 0.5 to 4 m, and with incidence angles ranging between 20° to 70°. Experimental results show an enhancement on the success in classification rates when these geometric features are considered.

  20. Contrast enhancement of intracranial lesions at 1.5 T: comparison among 2D spin echo, black-blood (BB) Cube, and BB Cube-FLAIR sequences

    Energy Technology Data Exchange (ETDEWEB)

    Im, SungWoon; Ashikaga, Ryuichiro; Yagyu, Yukinobu; Hyodo, Tomoko; Imaoka, Izumi; Kumano, Seishi; Ishii, Kazunari; Murakami, Takamichi [Kinki University Faculty of Medicine, Department of Radiology, Osaka-Sayama, Osaka (Japan); Wakayama, Tetsuya; Miyoshi, Mitsuharu [GE Healthcare Japan, MR Applications and Workflow, Asia Pacific, Hino, Tokyo (Japan)

    2015-11-15

    The purpose of this study was to investigate the usefulness of T1W black-blood Cube (BB Cube) and T1W BB Cube fluid-attenuated inversion recovery (BB Cube-FLAIR) sequences for contrast-enhanced brain imaging, by evaluating flow-related artefacts, detectability, and contrast ratio (CR) of intracranial lesions among these sequences and T1W-SE. Phantom studies were performed to determine the optimal parameters of BB Cube and BB Cube-FLAIR. A clinical study in 23 patients with intracranial lesions was performed to evaluate the usefulness of these two sequences for the diagnosis of intracranial lesions compared with the conventional 2D T1W-SE sequence. The phantom study revealed that the optimal parameters for contrast-enhanced T1W imaging were TR/TE = 500 ms/minimum in BB Cube and TR/TE/TI = 600 ms/minimum/300 ms in BB Cube-FLAIR imaging. In the clinical study, the degree of flow-related artefacts was significantly lower in BB Cube and BB Cube-FLAIR than in T1W-SE. Regarding tumour detection, BB Cube showed the best detectability; however, there were no significant differences in CR among the sequences. At 1.5 T, contrast-enhanced BB Cube was a better imaging sequence for detecting brain lesions than T1W-SE or BB Cube-FLAIR. (orig.)

  1. 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.

  2. Cadastral Surveys, SuveyedCorners, Published in 2008, Millard County.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Cadastral Surveys dataset, was produced all or in part from Other information as of 2008. It is described as 'SuveyedCorners'. Data by this publisher are often...

  3. Onboard autonomy on the Three Corner Sat Mission

    Science.gov (United States)

    Chien, S.; Engelhardt, B.; Knight, R.; Rabideau, G.; Sherwood, R.

    2001-01-01

    Three Corner Sat (3CS) is a mission of three university nanosatellites scheduled for launch on September 2002. The 3CS misison will utilize significan onboard autonomy to perform onboard science data validation and replanning.

  4. The MicroMAS CubeSat Mission

    Science.gov (United States)

    Cahoy, K.; Blackwell, W. J.; Allen, G.; Bury, M.; Efromson, R.; Galbraith, C.; Hancock, T.; Leslie, V.; Osaretin, I.; Retherford, L.; Scarito, M.; Shields, M.; Toher, D.; Wight, K.; Miller, D.; Marinan, A.; Paek, S.; Peters, E.; Schmidt, F. H.; Alvisio, B.; Wise, E.; Masterson, R.; Franzim Miranda, D.; Crail, C.; Kingsbury, R.; Souffrant, A.; Orrego, L.; Eslinger, G.; Nicholas, A.; Pong, C.

    2012-12-01

    The recently published Midterm Assessment of NASA's Implementation of the Decadal Survey finds that, "The nation's Earth observing system is beginning a rapid decline in capability as long-running missions end and key new missions are delayed, lost, or canceled. The projected loss of observing capability could have significant adverse consequences for science and society." In this presentation, we explore low-cost, mission-flexible, and rapidly deployable spaceborne sensors that can meet stringent performance requirements pervading the NASA Earth Science measurement programs, including especially the recommended NRC Decadal Survey missions. New technologies have enabled a novel approach toward this science observational goal, and in this paper we describe recent technology develop efforts to address the challenges above through the use of CubeSat radiometers. The Micro-sized Microwave Atmospheric Satellite (MicroMAS) is a 3U cubesat (30x10x10 cm, ~4kg) hosting a passive microwave spectrometer operating near the 118.75-GHz oxygen absorption line. The focus of the first MicroMAS mission (hereafter, MicroMAS-1) is to observe convective thunderstorms, tropical cyclones, and hurricanes from a near-equatorial orbit at approximately 500-km altitude. A MicroMAS flight unit is currently being developed in anticipation of a 2014 launch to be provided by NASA. A parabolic reflector is mechanically rotated as the spacecraft orbits the earth, thus directing a cross-track scanned beam with FWHM beamwidth of 2.4-degrees, yielding an approximately 25-km diameter footprint from a nominal altitude of 500 km. Radiometric calibration is carried out using observations of cold space, the earth's limb, and an internal noise diode that is weakly coupled through the RF front-end electronics. A key technology feature is the development of an ultra-compact intermediate frequency processor module for channelization, detection, and A-to-D conversion. The antenna system and RF front

  5. CubeSat Form Factor Thermal Control Louvers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Thermal control of small spacecraft, including CubeSats, is a challenge for the next era of NASA spaceflight. Science objectives and components will still require...

  6. CubeSat Capabilities for Space Science Missions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The CubeSat Capabilities for Space Science Missions combines science and engineering talent at Goddard Space Flight Center and the Wallops Flight Facility to...

  7. LunarCube for Deep Space Missions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Busek Co., Inc. and Morehead State University propose to develop a 6U CubeSat capable of reaching a lunar orbit from GEO. The primary objective is to demonstrate...

  8. Development of non-sweet, flavored food cubes

    Science.gov (United States)

    Larson, R. W.

    1971-01-01

    Food cubes exhibit flavor and quality stability for periods of four weeks in 100 deg F environment. They are suitable for field rations, emergency rations or snacks and should interest the food processing industry.

  9. "Soft docking": matching of molecular surface cubes.

    Science.gov (United States)

    Jiang, F; Kim, S H

    1991-05-05

    Molecular recognition is achieved through the complementarity of molecular surface structures and energetics with, most commonly, associated minor conformational changes. This complementarity can take many forms: charge-charge interaction, hydrogen bonding, van der Waals' interaction, and the size and shape of surfaces. We describe a method that exploits these features to predict the sites of interactions between two cognate molecules given their three-dimensional structures. We have developed a "cube representation" of molecular surface and volume which enables us not only to design a simple algorithm for a six-dimensional search but also to allow implicitly the effects of the conformational changes caused by complex formation. The present molecular docking procedure may be divided into two stages. The first is the selection of a population of complexes by geometric "soft docking", in which surface structures of two interacting molecules are matched with each other, allowing minor conformational changes implicitly, on the basis of complementarity in size and shape, close packing, and the absence of steric hindrance. The second is a screening process to identify a subpopulation with many favorable energetic interactions between the buried surface areas. Once the size of the subpopulation is small, one may further screen to find the correct complex based on other criteria or constraints obtained from biochemical, genetic, and theoretical studies, including visual inspection. We have tested the present method in two ways. First is a control test in which we docked the components of a molecular complex of known crystal structure available in the Protein Data Bank (PDB). Two molecular complexes were used: (1) a ternary complex of dihydrofolate reductase, NADPH and methotrexate (3DFR in PDB) and (2) a binary complex of trypsin and trypsin inhibitor (2PTC in PDB). The components of each complex were taken apart at an arbitrary relative orientation and then docked

  10. Searching for the corner seismic moment in worldwide data

    Energy Technology Data Exchange (ETDEWEB)

    Felgueiras, Miguel; Santos, Rui; Martins, João Paulo [CEAUL Lisbon and ESTG, Polytechnic Institute of Leiria (Portugal)

    2015-12-31

    In this paper the existence of the corner frequency value for the seismic moment distribution is investigated, analysing worldwide data. Pareto based distributions, usually considered as the most suitable to this type of data, are fitted to the most recent data, available in a global earthquake catalog. Despite the undeniable finite nature of the seismic moment data, we conclude that no corner frequency can be established considering the available data set.

  11. SQL Server Analysis Services 2012 cube development cookbook

    CERN Document Server

    Dewald, Baya; Hughes, Steve

    2013-01-01

    A practical cookbook packed with recipes to help developers produce data cubes as quickly as possible by following step by step instructions, rather than explaining data mining concepts with SSAS.If you are a BI or ETL developer using SQL Server Analysis services to build OLAP cubes, this book is ideal for you. Prior knowledge of relational databases and experience with Excel as well as SQL development is required.

  12. Mechanical Behavior of CFRP Lattice Core Sandwich Bolted Corner Joints

    Science.gov (United States)

    Zhu, Xiaolei; Liu, Yang; Wang, Yana; Lu, Xiaofeng; Zhu, Lingxue

    2017-02-01

    The lattice core sandwich structures have drawn more attention for the integration of load capacity and multifunctional applications. However, the connection of carbon fibers reinforced polymer composite (CFRP) lattice core sandwich structure hinders its application. In this paper, a typical connection of two lattice core sandwich panels, named as corner joint or L-joint, was investigated by experiment and finite element method (FEM). The mechanical behavior and failure mode of the corner joints were discussed. The results showed that the main deformation pattern and failure mode of the lattice core sandwich bolted corner joints structure were the deformation of metal connector and indentation of the face sheet in the bolt holes. The metal connectors played an important role in bolted corner joints structure. In order to save the calculation resource, a continuum model of pyramid lattice core was used to replace the exact structure. The computation results were consistent with experiment, and the maximum error was 19%. The FEM demonstrated the deflection process of the bolted corner joints structure visually. So the simplified FEM can be used for further analysis of the bolted corner joints structure in engineering.

  13. Miniature scientific-grade magnetic sensors for CubeSats

    Science.gov (United States)

    Pronenko, Vira; Belyayev, Serhiy

    2016-07-01

    Micro- and nanosatellites have become more attractive due to their low development and launch cost. A class of nanosatellites defined by the CubeSat standard allows standardizing CubeSat preparation and launch, thus making the projects more affordable. Because of the complexity of sensors miniaturization to install them onboard CubeSat, the majority of CubeSat launches are aimed the technology demonstration or education missions. The scientific success of CubeSat mission depends on the sensors quality. In spite that the sensitivity of the magnetic sensors strongly depends on their size, the recent development in this branch allows us to propose tiny but sensitive both AC and DC magnetometers. The goal of the present report is to introduce the new design of miniature three-component sensors for measurement of vector magnetic fields - for quasi-stationary and slowly fluctuating - flux-gate magnetometer (FGM) - and for alternative ones - search-coil magnetometer (SCM). In order to create magnetometers with the really highest possible level of parameters, a set of scientific and technological problems, mostly aimed at the sensor construction improvement, was solved. The most important parameter characterizing magnetometer quality is its own magnetic noise level (NL). The analysis of the NL influencing factors is made and the ways to decrease it are discussed in the report. Construction details and technical specifications of miniature but sensitive FGM and SCM for the CubeSat mission are presented. This work is supported by EC Framework 7 funded project 607197.

  14. Pick Cubes for Object Picking in VR World

    Directory of Open Access Journals (Sweden)

    M. Mohamed Sathik

    2010-02-01

    Full Text Available In this paper, we proposed an algorithm which performs object picking in Virtualreality world using cubes. As ‘Picking’ is an essential interaction technique in graphics applications,Object Picking is performed in VR world using a 3D mouse or an interactive glove to explore andinteract with any of the objects. In this paper, cube is used to represent the intersection point of the raycoming from the user input and the object to be picked. By intersecting the objects in the scene with theray with a pick cube at the intersection point, it is determined which one is picked. An object is selectedwhen this pick cube intersects the object’s bounding box. In this paper, object picking is typicallyperformed by bounding box checks, taking the position of the pick cube and the objects in account so thatthe algorithm is made simpler and the computation time of the algorithm is also reduced. Pick cube canbe activated to perform more actions during interactions than other shapes. So the efficiency and theperformance of the picking process will be increased which helps the user to play in the virtual worldwith full enthusiasm.

  15. Black Holes at IceCube

    CERN Document Server

    Anchordoqui, L A; Parker, L; Anchordoqui, Luis A.; Glenz, Matthew M.; Parker, Leonard

    2007-01-01

    If the fundamental Planck scale is about a TeV and the cosmic neutrino flux is at the Waxman-Bahcall level, quantum black holes are created daily in the Antarctic ice-cap. We re-examine the prospects for observing such black holes with the IceCube neutrino-detection experiment. To this end, we first revise the black hole production rate by incorporating the effects of inelasticty, i.e., the energy radiated in gravitational waves by the multipole moments of the incoming shock waves. After that we study in detail the process of Hawking evaporation accounting for the black hole's large momentum in the lab system. We derive the energy spectrum of the Planckian cloud which is swept forward with a large, O (10^6), Lorentz factor. (It is noteworthy that the boosted thermal spectrum is also relevant for the study of near-extremal supersymmetric black holes, which could be copiously produced at the LHC.) In the semiclassical regime, we estimate the average energy of the boosted particles to be less than 20% the energy...

  16. 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.

  17. 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.

  18. 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)

  19. 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.

  20. 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.

  1. Evaluation of the Impact of an Additive Manufacturing Enhanced CubeSat Architecture on the CubeSat Development Process

    Science.gov (United States)

    2016-09-15

    methods are needed in the CubeSat development process to reduce the weight and volume of subsystems and decrease integration time. Research Objective and...Investigative Questions This research will quantitatively address the impact of proposed benefits of a 3D printed satellite architecture on the...subsystems of a CubeSat. The objective of this research is to bring a quantitative analysis to the discussion of whether a fully 3D printed satellite

  2. EarthCube: A Community Organization for Geoscience Cyberinfrastructure

    Science.gov (United States)

    Patten, K.; Allison, M. L.

    2014-12-01

    The National Science Foundation's (NSF) EarthCube initiative is a community-driven approach to building cyberinfrastructure for managing, sharing, and exploring geoscience data and information to better address today's grand-challenge science questions. The EarthCube Test Enterprise Governance project is a two-year effort seeking to engage diverse geo- and cyber-science communities in applying a responsive approach to the development of a governing system for EarthCube. During Year 1, an Assembly of seven stakeholder groups representing the broad EarthCube community developed a draft Governance Framework. Finalized at the June 2014 EarthCube All Hands Meeting, this framework will be tested during the demonstration phase in Year 2, beginning October 2014. A brief overview of the framework: Community-elected members of the EarthCube Leadership Council will be responsible for managing strategic direction and identifying the scope of EarthCube. Three Standing Committees will also be established to oversee the development of technology and architecture, to coordinate among new and existing data facilities, and to represent the academic geosciences community in driving development of EarthCube cyberinfrastructure. An Engagement Team and a Liaison Team will support communication and partnerships with internal and external stakeholders, and a central Office will serve a logistical support function to the governance as a whole. Finally, ad hoc Working Groups and Special Interest Groups will take on other issues related to EarthCube's goals. The Year 2 demonstration phase will test the effectiveness of the proposed framework and allow for elements to be changed to better meet community needs. It will begin by populating committees and teams, and finalizing leadership and decision-making processes to move forward on community-selected priorities including identifying science drivers, coordinating emerging technical elements, and coming to convergence on system architecture. A

  3. 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.

  4. 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...

  5. 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.

  6. 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.

  7. 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.

  8. 数据立方梯度挖掘的研究%The Research of the Cube Gradient Mining

    Institute of Scientific and Technical Information of China (English)

    刘玉葆; 冯玉才; 王元珍; 冯剑琳

    2003-01-01

    With the rapid development of data warehouse and OLAP techniques, the researchers begin to pay atten-tion to the data mining in the data cube. Recently, Dr. T. Imielinski etc. firstly presented the problem of the cubegradient mining that is a generalization of association rule in data cube. In this paper, we firstly introduce the relatedconcepts of data cube and condensed cube with an emphasis. Then we introduce some interesting problems related tothe cube gradient mining including: constrained cube gradient mining and the query language of cube gradient. Final-ly, we introduce several issues on the combination of cube gradient and the condensed cube, that is, the cube gradientmining in the materialized data cube and the integration of cube gradient mining and cube browse.

  9. 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.

  10. Corner rounding in EUV photoresist: tuning through molecular weight, PAG size, and development time

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Christopher; Daggett, Joe; Naulleau, Patrick

    2009-12-31

    In this paper, the corner rounding bias of a commercially available extreme ultraviolet photoresist is monitored as molecular weight, photoacid generator (PAG) size, and development time are varied. These experiments show that PAG size influences corner biasing while molecular weight and development time do not. Large PAGs are shown to exhibit less corner biasing, and in some cases, lower corner rounding, than small PAGs. In addition, heavier resist polymers are shown to exhibit less corner rounding than lighter ones.

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. 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

  17. 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.

  18. Scalable desktop visualisation of very large radio astronomy data cubes

    Science.gov (United States)

    Perkins, Simon; Questiaux, Jacques; Finniss, Stephen; Tyler, Robin; Blyth, Sarah; Kuttel, Michelle M.

    2014-07-01

    Observation data from radio telescopes is typically stored in three (or higher) dimensional data cubes, the resolution, coverage and size of which continues to grow as ever larger radio telescopes come online. The Square Kilometre Array, tabled to be the largest radio telescope in the world, will generate multi-terabyte data cubes - several orders of magnitude larger than the current norm. Despite this imminent data deluge, scalable approaches to file access in Astronomical visualisation software are rare: most current software packages cannot read astronomical data cubes that do not fit into computer system memory, or else provide access only at a serious performance cost. In addition, there is little support for interactive exploration of 3D data. We describe a scalable, hierarchical approach to 3D visualisation of very large spectral data cubes to enable rapid visualisation of large data files on standard desktop hardware. Our hierarchical approach, embodied in the AstroVis prototype, aims to provide a means of viewing large datasets that do not fit into system memory. The focus is on rapid initial response: our system initially rapidly presents a reduced, coarse-grained 3D view of the data cube selected, which is gradually refined. The user may select sub-regions of the cube to be explored in more detail, or extracted for use in applications that do not support large files. We thus shift the focus from data analysis informed by narrow slices of detailed information, to analysis informed by overview information, with details on demand. Our hierarchical solution to the rendering of large data cubes reduces the overall time to complete file reading, provides user feedback during file processing and is memory efficient. This solution does not require high performance computing hardware and can be implemented on any platform supporting the OpenGL rendering library.

  19. Corner Rounding in Photoresists for Extreme Ultraviolet Lithography

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Christopher N.; Naulleau, Patrick; Deng, Yunfei; Wallow, Thomas

    2008-06-01

    Deprotection blur in EUV resists fundamentally limits the smallest sized dense features that can be patterned in a single exposure and development step. Several metrics have recently been developed to explore the ways that different resist and process parameters affect the deprotection blur in EUV resists. One of these metrics is based on the imaging fidelity of a sharp corner on a large feature. As this metric has involved the close inspection of printing fidelity of corner features, it has brought attention to an interesting phenomena: corners print differently whether or not the remaining resist edge contains 270 degrees of resist or 90 degrees of resist. Here we present experimental data across a wide sampling of leading resists to show this effect is real and reproducible. They provide aerial image modeling results assuming thin and realistic mask models that show no corner bias between the aerial images in the 90-degree and 270-degree configurations. They also compare modeled patterning results assuming several resist models including the single blur, dual blur, and Prolith models, none of which reproduce the corner biasing that is observed experimentally.

  20. An evaluation of some unbraked tire cornering force characteristics

    Science.gov (United States)

    Leland, T. J. W.

    1972-01-01

    An investigation to determine the effects of pavement surface condition on the cornering forces developed by a group of 6.50x13 automobile tires of different tread design was conducted at the Langley aircraft landing loads and traction facility. The tests were made at fixed yaw angles of 3,4.5, and 6 deg at forward speeds up to 80 knots on two concrete surfaces of different texture under dry, damp, and flooded conditions. The results showed that the cornering forces were extremely sensitive to tread pattern and runway surface texture under all conditions and that under flooded conditions tire hydroplaning and complete loss of cornering force occurred at a forward velocity predicted from an existing formula based on tire inflation pressure. Futher, tests on the damp concrete with a smooth tire and a four-groove tire showed higher cornering forces at a yaw angle of 3 deg than at 4.5 deg; this indicated that maximum cornering forces are developed at extremely small steering angles under these conditions.

  1. a Novel and Fast Corner Detection Method for SAR Imagery

    Science.gov (United States)

    Jiao, N.; Kang, W.; Xiang, Y.; You, H.

    2017-09-01

    Corners play an important role on image processing, while it is difficult to detect reliable and repeatable corners in SAR images due to the complex property of SAR sensors. In this paper, we propose a fast and novel corner detection method for SAR imagery. First, a local processing window is constructed for each point. We use the local mean of a 3 x 3 mask to represent a single point, which is weighted by a Gaussian template. Then the candidate point is compared with 16 surrounding points in the processing window. Considering the multiplicative property of speckle noise, the similarity measure between the center point and the surrounding points is calculated by the ratio of their local means. If there exist more than M continuous points are different from the center point, then the candidate point is labelled as a corner point. Finally, a selection strategy is implemented by ranking the corner score and employing the non-maxima suppression method. Extreme situations such as isolated bright points are also removed. Experimental results on both simulated and real-world SAR images show that the proposed detector has a high repeatability and a low localization error, compared with other state-of-the-art detectors.

  2. Supercritical flows past a square cylinder with rounded corners

    Science.gov (United States)

    Cao, Yong; Tamura, Tetsuro

    2017-08-01

    Large-eddy simulations were used to investigate the supercritical aerodynamics of a square cylinder with rounded corners in comparison with those in the subcritical regime. First, the numerical methods, especially the dynamic mixed model, were validated on the basis of their prediction of supercritical flows past a circular cylinder. Then, the supercritical flows past a rounded-corner square cylinder were simulated and systematically clarified. Strong Reynolds number (Re) effects existed in the forces and local pressures as Re increased from o(104) to o(106). Changeover of flow patterns occurred as Re increased. At the supercritical Re, the free stream overall flowed along the cross sections of the cylinder, separated from the leeward corners and generated Karman vortices behind the cylinder. This pattern resulted in a much smaller recirculation region behind the cylinder compared with the subcritical flow. At the micro level, the flow experienced laminar separation and flow reattachment near the frontal corners, followed by the spatial development of turbulent boundary layers (TBLs) on the side faces and turbulent separation near the leeward corners. The feedback by large-scale primary vortex shedding and the small-scale turbulent motions in the high-frequency region with a slope of -5/3 were detected in the TBL. Their interaction affected the spanwise correlations of wall pressure fluctuations. The TBL on the side face differed from the zero-pressure-gradient flat-plate one; it was subjected to pressure gradients varying in space and time.

  3. Very-high-energy astrophysical neutrinos with IceCube

    Directory of Open Access Journals (Sweden)

    Taboada Ignacio

    2016-01-01

    Full Text Available IceCube is a ≳TeV neutrino observatory operating at the South Pole. Ice-Cube has observed a flux of neutrinos of astrophysical origin, with energies beyond 2 PeV. However the sources of these neutrinos have not yet been identified. A summary of various IceCube observations is presented. The results discussed were obtained through several different analysis methods, which have varying sensitivity to the different neutrino flavors. A discussion of the spectral fit obtained for the various event selections is included, as well as the constraints on the astrophysical neutrino flavor flux ratio. Several attempts by IceCube to identify the sources of these neutrinos are described. These include studies correlating neutrino events with catalogs of sources as well as selfcorrelations among IceCube’s neutrinos. The observations of astrophysical neutrinos are limited by statistics. So an upgrade of IceCube, including a larger detector and a surface veto is planned. This upgrade is briefly discussed.

  4. Latest results from the IceCube neutrino observatory

    Energy Technology Data Exchange (ETDEWEB)

    Schukraft, Anne [RWTH Aachen Univ. (Germany). III. Physikalisches Inst.; Collaboration: IceCube-Collaboration

    2013-07-01

    The IceCube Neutrino Observatory is the world's largest neutrino detector with a broad physics program covering the neutrino spectrum from several tens of GeV up to EeV energies. With its completion in 2010 it has reached its full sensitivity and analyses with unprecedented statistics are performed. One of the major research efforts is the search for extraterrestrial neutrino sources, which have not yet been discovered but would be a smoking gun for hadronic acceleration and could allow to identify the sources of high-energy cosmic rays. Such include steady galactic and extragalactic source candidates, e.g. Supernova Remnants and Active Galactic Nuclei, as well as transient phenomena like flaring objects and Gamma Ray Bursts. With its searches for diffuse neutrino fluxes in different energy ranges, IceCube is sensitive to fluxes of prompt atmospheric neutrinos, extragalactic neutrinos and cosmogenic neutrinos. In the low-energy range below 100 GeV, IceCube supplements classical neutrino oscillation experiments with its sensitivity to the deficit of atmospheric muon neutrinos at 25 GeV and searches for neutrinos from the annihilation of dark matter. The IceCube physics program is complemented by the surface array IceTop, which together with the detector part inside the ice serves for cosmic ray anisotropy, spectrum and composition measurements around the knee. The presentation summarizes ongoing IceCube physics analyses and recent results.

  5. Using the multistage cube network topology in parallel supercomputers

    Energy Technology Data Exchange (ETDEWEB)

    Siegel, H.J.; Nation, W.G. (Purdue Univ., Lafayette, IN (USA). School of Electrical Engineering); Kruskal, C.P. (Maryland Univ., College Park, MD (USA). Dept. of Computer Science); Napolitano, L.M. Jr. (Sandia National Labs., Livermore, CA (USA))

    1989-12-01

    A variety of approaches to designing the interconnection network to support communications among the processors and memories of supercomputers employing large-scale parallel processing have been proposed and/or implemented. These approaches are often based on the multistage cube topology. This topology is the subject of much ongoing research and study because of the ways in which the multistage cube can be used. The attributes of the topology that make it useful are described. These include O(N log{sub 2} N) cost for an N input/output network, decentralized control, a variety of implementation options, good data permuting capability to support single instruction stream/multiple data stream (SIMD) parallelism, good throughput to support multiple instruction stream/multiple data stream (MIMD) parallelism, and ability to be partitioned into independent subnetworks to support reconfigurable systems. Examples of existing systems that use multistage cube networks are overviewed. The multistage cube topology can be converted into a single-stage network by associating with each switch in the network a processor (and a memory). Properties of systems that use the multistage cube network in this way are also examined.

  6. The motion of a deforming capsule through a corner

    CERN Document Server

    Zhu, Lailai

    2014-01-01

    A three-dimensional deformable capsule convected through a channel/duct with a corner is studied via numerical simulations using an accelerated boundary integral method adapted to general geometries. A global spectral method is adopted to resolve the dynamics of the capsule's membrane developing elastic tensions according to the Neo-Hookean constitutive law and bending moments in an inertialess flow. The simulations show that the trajectory of the capsule closely follows the underlying streamlines and the deformation of the capsule induces an anti-clockwise rotation of its material points with respect to the travelling direction. The surface area, principle tension and elastic energy of the capsule increase around the corner. Their temporal evolutions are characterised by a clear phase delay and the loss of time-reversal symmetry of Stokes flow due to the elasticity of membrane. The capsule centroid velocity decreases approaching the corner as the mean flow does while a velocity overshoot is observed past the...

  7. Ballistic rectification of vortex domain wall chirality at nanowire corners

    Energy Technology Data Exchange (ETDEWEB)

    Omari, K.; Bradley, R. C.; Broomhall, T. J.; Hodges, M. P. P.; Hayward, T. J. [Department of Materials Science and Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom); Rosamond, M. C.; Linfield, E. H. [School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT (United Kingdom); Im, M.-Y. [Center for X-Ray Optics, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Daegu Gyeongbuk Institute of Science and Technology, Daegu 711-873 (Korea, Republic of); Fischer, P. [Materials Sciences Division, Lawrence Berkley National Laboratory, Berkeley, California 94720 (United States); Department of Physics, University of California, Santa Cruz, California 94056 (United States)

    2015-11-30

    The interactions of vortex domain walls with corners in planar magnetic nanowires are probed using magnetic soft X-ray transmission microscopy. We show that when the domain walls are propagated into sharp corners using applied magnetic fields above a critical value, their chiralities are rectified to either clockwise or anticlockwise circulation depending on whether the corners turn left or right. Single-shot focused magneto-optic Kerr effect measurements are then used to demonstrate how, when combined with modes of domain propagation that conserve vortex chirality, this allows us to dramatically reduce the stochasticity of domain pinning at artificial defect sites. Our results provide a tool for controlling domain wall chirality and pinning behavior both in further experimental studies and in future domain wall-based memory, logic and sensor technologies.

  8. 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

  9. 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.

  10. 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...

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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...

  2. 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.

  3. IceCube and high-energy neutrinos

    Science.gov (United States)

    Niro, V.

    2015-01-01

    The recent IceCube observation of the first high-energy neutrinos has received the Physics World award for the Breakthrough of the Year 2013. In the light of this important discovery, we revisit the possibility of observing, at the IceCube detector, three Milagro sources: MGRO J2019+ 37, MGRO J1908+ 06 and MGRO J2031+ 41. Moreover, we present a discussion on the possible galactic origin of some of the IceCube events and we comment on the possibility that the high-energy neutrinos detected might come from a Dark Matter decay. Finally, we comment on other important consequences of this discovery, like bounds on Lorentz-invariance violation and on secret neutrino interactions.

  4. Performing High-Quality Science on CubeSats

    DEFF Research Database (Denmark)

    H. Zurbuchen, Thomas; von Steiger, Rudolf; Bartalev, Sergey

    2016-01-01

    January 2016 the International Space Science Institute in Berne, Switzerland,hosted a two-day Forum to focus on the rapid evolution of CubeSats as an enabling technology platform, with special emphasis on their promise to perform high-quality science.The Forum was initiated in coordination...... in this area of research. Our discussions focused on four themes characteristic of CubeSats and their evolution: 1) identification of appropriate science in avariety of research disciplines, 2) technology development, 3) international vs. national approaches, and 4) educational benefits. These discussions...... with a then ongoing, and recently published study performed by the US National Academies onthe same topic (goo.gl/osCSQ3), and was focused on the international context of CubeSats-enabled science. This report summarizes the conclusions from this Forum to inform the growing international community of the activities...

  5. Cube orientation in hot rolled high purity aluminum plate

    Institute of Scientific and Technical Information of China (English)

    杨平; 毛卫民

    2003-01-01

    X-ray diffraction and orientation mapping in EBSD measurement were applied to obtain information ofdeformation and recrystallization with the emphasis on the cube orientation in hot rolled high purity aluminumplates. It is shown that cube orientations are retained to a large extent during hot rolling. Some deformed cubegrains are found to have experienced large extent of recovery according to their Kikuchi band contrasts. The de-formed cube-oriented grains in hot rolled plates are in an unfavorite growth condition with respect to their neighbor-ing grain orientations for the subsequent annealing. The reasons for the phenomena observed, as well as the influ-ence of hot rolling process on subsequent cold rolling and final annealing were discussed.

  6. Neutrino oscillation studies with IceCube-DeepCore

    Science.gov (United States)

    Aartsen, M. G.; Abraham, K.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Ahrens, M.; Altmann, D.; Anderson, T.; Ansseau, I.; Archinger, M.; Arguelles, C.; Arlen, T. C.; Auffenberg, J.; Bai, X.; Barwick, S. W.; Baum, V.; Bay, R.; Beatty, J. J.; Becker Tjus, J.; Becker, K.-H.; Beiser, E.; Berghaus, P.; Berley, D.; Bernardini, E.; Bernhard, A.; Besson, D. Z.; Binder, G.; Bindig, D.; Bissok, M.; Blaufuss, E.; Blumenthal, J.; Boersma, D. J.; Bohm, C.; Börner, M.; Bos, F.; Bose, D.; Böser, S.; Botner, O.; Braun, J.; Brayeur, L.; Bretz, H.-P.; Buzinsky, N.; Casey, J.; Casier, M.; Cheung, E.; Chirkin, D.; Christov, A.; Clark, K.; Classen, L.; Coenders, S.; Collin, G. H.; Conrad, J. M.; Cowen, D. F.; Cruz Silva, A. H.; Daughhetee, J.; Davis, J. C.; Day, M.; de André, J. P. A. M.; De Clercq, C.; del Pino Rosendo, E.; Dembinski, H.; De Ridder, S.; Desiati, P.; de Vries, K. D.; de Wasseige, G.; de With, M.; DeYoung, T.; Díaz-Vélez, J. C.; di Lorenzo, V.; Dumm, J. P.; Dunkman, M.; Eberhardt, B.; Ehrhardt, T.; Eichmann, B.; Euler, S.; Evenson, P. A.; Fahey, S.; Fazely, A. R.; Feintzeig, J.; Felde, J.; Filimonov, K.; Finley, C.; Flis, S.; Fösig, C.-C.; Fuchs, T.; Gaisser, T. K.; Gaior, R.; Gallagher, J.; Gerhardt, L.; Ghorbani, K.; Gier, D.; Gladstone, L.; Glagla, M.; Glüsenkamp, T.; Goldschmidt, A.; Golup, G.; Gonzalez, J. G.; Góra, D.; Grant, D.; Griffith, Z.; Groß, A.; Ha, C.; Haack, C.; Haj Ismail, A.; Hallgren, A.; Halzen, F.; Hansen, E.; Hansmann, B.; Hanson, K.; Hebecker, D.; Heereman, D.; Helbing, K.; Hellauer, R.; Hickford, S.; Hignight, J.; Hill, G. C.; Hoffman, K. D.; Hoffmann, R.; Holzapfel, K.; Homeier, A.; Hoshina, K.; Huang, F.; Huber, M.; Huelsnitz, W.; Hulth, P. O.; Hultqvist, K.; In, S.; Ishihara, A.; Jacobi, E.; Japaridze, G. S.; Jeong, M.; Jero, K.; Jones, B. J. P.; Jurkovic, M.; Kappes, A.; Karg, T.; Karle, A.; Kauer, M.; Keivani, A.; Kelley, J. L.; Kemp, J.; Kheirandish, A.; Kiryluk, J.; Klein, S. R.; Kohnen, G.; Koirala, R.; Kolanoski, H.; Konietz, R.; Köpke, L.; Kopper, C.; Kopper, S.; Koskinen, D. J.; Kowalski, M.; Krings, K.; Kroll, G.; Kroll, M.; Krückl, G.; Kunnen, J.; Kurahashi, N.; Kuwabara, T.; Labare, M.; Lanfranchi, J. L.; Larson, M. J.; Lesiak-Bzdak, M.; Leuermann, M.; Leuner, J.; Lu, L.; Lünemann, J.; Madsen, J.; Maggi, G.; Mahn, K. B. M.; Mandelartz, M.; Maruyama, R.; Mase, K.; Matis, H. S.; Maunu, R.; McNally, F.; Meagher, K.; Medici, M.; Meli, A.; Menne, T.; Merino, G.; Meures, T.; Miarecki, S.; Middell, E.; Mohrmann, L.; Montaruli, T.; Morse, R.; Nahnhauer, R.; Naumann, U.; Neer, G.; Niederhausen, H.; Nowicki, S. C.; Nygren, D. R.; Obertacke Pollmann, A.; Olivas, A.; Omairat, A.; O'Murchadha, A.; Palczewski, T.; Pandya, H.; Pankova, D. V.; Paul, L.; Pepper, J. A.; Pérez de los Heros, C.; Pfendner, C.; Pieloth, D.; Pinat, E.; Posselt, J.; Price, P. B.; Przybylski, G. T.; Quinnan, M.; Raab, C.; Rädel, L.; Rameez, M.; Rawlins, K.; Reimann, R.; Relich, M.; Resconi, E.; Rhode, W.; Richman, M.; Richter, S.; Riedel, B.; Robertson, S.; Rongen, M.; Rott, C.; Ruhe, T.; Ryckbosch, D.; Sabbatini, L.; Sander, H.-G.; Sandrock, A.; Sandroos, J.; Sarkar, S.; Schatto, K.; Schimp, M.; Schmidt, T.; Schoenen, S.; Schöneberg, S.; Schönwald, A.; Schulte, L.; Schumacher, L.; Seckel, D.; Seunarine, S.; Soldin, D.; Song, M.; Spiczak, G. M.; Spiering, C.; Stahlberg, M.; Stamatikos, M.; Stanev, T.; Stasik, A.; Steuer, A.; Stezelberger, T.; Stokstad, R. G.; Stößl, A.; Ström, R.; Strotjohann, N. L.; Sullivan, G. W.; Sutherland, M.; Taavola, H.; Taboada, I.; Tatar, J.; Ter-Antonyan, S.; Terliuk, A.; Tešić, G.; Tilav, S.; Toale, P. A.; Tobin, M. N.; Toscano, S.; Tosi, D.; Tselengidou, M.; Turcati, A.; Unger, E.; Usner, M.; Vallecorsa, S.; Vandenbroucke, J.; van Eijndhoven, N.; Vanheule, S.; van Santen, J.; Veenkamp, J.; Vehring, M.; Voge, M.; Vraeghe, M.; Walck, C.; Wallace, A.; Wallraff, M.; Wandkowsky, N.; Weaver, Ch.; Wendt, C.; Westerhoff, S.; Whelan, B. J.; Wiebe, K.; Wiebusch, C. H.; Wille, L.; Williams, D. R.; Wills, L.; Wissing, H.; Wolf, M.; Wood, T. R.; Woschnagg, K.; Xu, D. L.; Xu, X. W.; Xu, Y.; Yanez, J. P.; Yodh, G.; Yoshida, S.; Zoll, M.

    2016-07-01

    IceCube, a gigaton-scale neutrino detector located at the South Pole, was primarily designed to search for astrophysical neutrinos with energies of PeV and higher. This goal has been achieved with the detection of the highest energy neutrinos to date. At the other end of the energy spectrum, the DeepCore extension lowers the energy threshold of the detector to approximately 10 GeV and opens the door for oscillation studies using atmospheric neutrinos. An analysis of the disappearance of these neutrinos has been completed, with the results produced being complementary with dedicated oscillation experiments. Following a review of the detector principle and performance, the method used to make these calculations, as well as the results, is detailed. Finally, the future prospects of IceCube-DeepCore and the next generation of neutrino experiments at the South Pole (IceCube-Gen2, specifically the PINGU sub-detector) are briefly discussed.

  7. Fast Computation of Sparse Data Cubes with Constraints

    Institute of Scientific and Technical Information of China (English)

    Feng Yu-cai; Chen Chang-qing; Feng Jian-lin; Xiang Long-gang

    2004-01-01

    For a data cube there are always constraints between dimensions or among attributes in a dimension, such as functional dependencies. We introduce the problem that when there are functional dependencies, how to use them to speed up the computation of sparse data cubes. A new algorithm CFD (Computation by Functional Dependencies) is presented to satisfy this demand. CFD determines the order of dimensions by considering cardinalities of dimensions and functional dependencies between dimensions together, thus reduce the number of partitions for such dimensions. CFD also combines partitioning from bottom to up and aggregate computation from top to bottom to speed up the computation further. CFD can efficiently compute a data cube with hierarchies in a dimension from the smallest granularity to the coarsest one.

  8. Recent results from the IceCube Neutrino Observatory

    Energy Technology Data Exchange (ETDEWEB)

    Schoenen, Sebastian [3. Physikalisches Institut B, RWTH Aachen (Germany); Collaboration: IceCube-Collaboration

    2016-07-01

    The IceCube Neutrino Observatory is a cubic-kilometer Cherenkov telescope buried deep in the glacial ice at the geographic South Pole. It is a multi-purpose detector covering a broad physics program in high-energy neutrino astronomy and particle physics. Already the data from IceCube's first few years of operation have revealed an excess of high-energy neutrino events in multiple detection channels from a few tens of TeV up to a few PeV. The flux observed at these energies is incompatible with a purely atmospheric origin and thus confirmed the existence of a high-energy extraterrestrial neutrino flux. However, the astrophysical sources of this flux still remain unresolved. In this talk we provide an overview about recent IceCube results in the field of neutrino astrophysics.

  9. Primary spectrum and composition with IceCube/IceTop

    CERN Document Server

    ,

    2016-01-01

    IceCube, with its surface array IceTop, detects three different components of extensive air showers: the total signal at the surface, GeV muons in the periphery of the showers and TeV muons in the deep array of IceCube. The spectrum is measured with high resolution from the knee to the ankle with IceTop. Composition and spectrum are extracted from events seen in coincidence by the surface array and the deep array of IceCube. The muon lateral distribution at the surface is obtained from the data and used to provide a measurement of the muon density at 600 meters from the shower core up to 30 PeV. Results are compared to measurements from other experiments to obtain an overview of the spectrum and composition over an extended range of energy. Consistency of the surface muon measurements with hadronic interaction models and with measurements at higher energy is discussed.

  10. Neutrino oscillation studies with IceCube-DeepCore

    Energy Technology Data Exchange (ETDEWEB)

    Aartsen, M.G. [Department of Physics, University of Adelaide, Adelaide, 5005 (Australia); Abraham, K. [Technische Universität München, D-85748 Garching (Germany); Ackermann, M. [DESY, D-15735 Zeuthen (Germany); Adams, J. [Dept. of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch (New Zealand); Aguilar, J.A. [Université Libre de Bruxelles, Science Faculty CP230, B-1050 Brussels (Belgium); Ahlers, M. [Dept. of Physics and Wisconsin IceCube Particle Astrophysics Center, University of Wisconsin, Madison, WI 53706 (United States); Ahrens, M. [Oskar Klein Centre and Dept. of Physics, Stockholm University, SE-10691 Stockholm (Sweden); Altmann, D. [Erlangen Centre for Astroparticle Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, D-91058 Erlangen (Germany); Anderson, T. [Dept. of Physics, Pennsylvania State University, University Park, PA 16802 (United States); Ansseau, I. [Université Libre de Bruxelles, Science Faculty CP230, B-1050 Brussels (Belgium); Archinger, M. [Institute of Physics, University of Mainz, Staudinger Weg 7, D-55099 Mainz (Germany); Arguelles, C. [Dept. of Physics and Wisconsin IceCube Particle Astrophysics Center, University of Wisconsin, Madison, WI 53706 (United States); Arlen, T.C. [Dept. of Physics, Pennsylvania State University, University Park, PA 16802 (United States); Auffenberg, J. [III. Physikalisches Institut, RWTH Aachen University, D-52056 Aachen (Germany); Bai, X. [Physics Department, South Dakota School of Mines and Technology, Rapid City, SD 57701 (United States); Barwick, S.W. [Dept. of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Baum, V. [Institute of Physics, University of Mainz, Staudinger Weg 7, D-55099 Mainz (Germany); and others

    2016-07-15

    IceCube, a gigaton-scale neutrino detector located at the South Pole, was primarily designed to search for astrophysical neutrinos with energies of PeV and higher. This goal has been achieved with the detection of the highest energy neutrinos to date. At the other end of the energy spectrum, the DeepCore extension lowers the energy threshold of the detector to approximately 10 GeV and opens the door for oscillation studies using atmospheric neutrinos. An analysis of the disappearance of these neutrinos has been completed, with the results produced being complementary with dedicated oscillation experiments. Following a review of the detector principle and performance, the method used to make these calculations, as well as the results, is detailed. Finally, the future prospects of IceCube-DeepCore and the next generation of neutrino experiments at the South Pole (IceCube-Gen2, specifically the PINGU sub-detector) are briefly discussed.

  11. Corner junction as a probe of helical edge states.

    Science.gov (United States)

    Hou, Chang-Yu; Kim, Eun-Ah; Chamon, Claudio

    2009-02-20

    We propose and analyze interedge tunneling in a quantum spin Hall corner junction as a means to probe the helical nature of the edge states. We show that electron-electron interactions in the one-dimensional helical edge states result in Luttinger parameters for spin and charge that are intertwined, and thus rather different from those for a quantum wire with spin rotation invariance. Consequently, we find that the four-terminal conductance in a corner junction has a distinctive form that could be used as evidence for the helical nature of the edge states.

  12. 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.

  13. Chemical composition of primary cosmic rays with IceCube

    Science.gov (United States)

    Xu, Chen

    Ground detector arrays have been used to measure high energy cosmic rays for decades to overcome their very low rate. IceCube is a special case with its 3D deployment and unique location---the South Pole. Although all 86 strings and 81 stations of IceCube were completed in 2011, IceCube began to take data in 2006, after the completion of the first 9 strings. In this thesis, experimental data taken in 2009 with 59 strings are used for composition analysis albeit some techniques are illustrated with the 40-string data. Simulation is essential in the composition work. Simulated data must be compared against the experimental data to find the right mix of cosmic ray components. However, because of limited computing resources and complexities of cosmic rays, the simulation in IceCube is well behind the experiment. The lower and upper bounds of primary energy in simulation for events that go through IceTop and the deep arrays of IceCube are 1014 eV and 1017 eV. However, since IceCube has a threshold energy about several hundred TeV, and an upper limit of 10 18 eV, the full energy range cannot be explored in this thesis. The approach taken to the composition problem in this thesis is a 2D Bayesian unfolding. It takes account of the measured IceTop and InIce energy spectrum and outputs the expected primary energy spectrum of different mass components. Studies of the uncertainties in the results are not complete because of limited simulation and understanding of the new detector and South Pole environment.

  14. Low-energy point source searches with IceCube

    Directory of Open Access Journals (Sweden)

    Euler Sebastian

    2016-01-01

    Full Text Available Due to the overwhelming background of atmospheric muons, the traditional IceCube point source search in the Southern Hemisphere is mainly sensitive to neutrinos with energies above 100TeV. A new approach focuses on events starting inside the instrumented volume. By utilizing different veto techniques we are able to significantly reduce the energy threshold and can now for the first time explore the entire Southern Hemisphere at neutrino energies as low as 100GeV. We present the results of two analyses targeting slightly different energy ranges. Both use one year of data taken with the completed IceCube detector in 2011/12.

  15. Instant SQL Server Analysis Services 2012 Cube Security

    CERN Document Server

    Jayanty, Satya SK

    2013-01-01

    Filled with practical, step-by-step instructions and clear explanations for the most important and useful tasks. Instant Microsoft SQL Server Analysis Services 2012 Cube Security is a practical, hands-on guide that provides a number of clear, step-by-step exercises for getting started with cube security.This book is aimed at Database Administrators, Data Architects, and Systems Administrators who are managing the SQL Server data platform. It is also beneficial for analysis services developers who already have some experience with the technology, but who want to go into more detail on advanced

  16. Optimizing RDF Data Cubes for Efficient Processing of Analytical Queries

    DEFF Research Database (Denmark)

    Jakobsen, Kim Ahlstrøm; Andersen, Alex B.; Hose, Katja

    2015-01-01

    data warehouses and data cubes. Today, external data sources are essential for analytics and, as the Semantic Web gains popularity, more and more external sources are available in native RDF. With the recent SPARQL 1.1 standard, performing analytical queries over RDF data sources has finally become......In today’s data-driven world, analytical querying, typically based on the data cube concept, is the cornerstone of answering important business questions and making data-driven decisions. Traditionally, the underlying analytical data was mostly internal to the organization and stored in relational...

  17. Integrated Solar-Panel Antenna Array for CubeSats

    Science.gov (United States)

    Baktur, Reyhan

    2016-01-01

    The goal of the Integrated Solar-Panel Antenna Array for CubeSats (ISAAC) project is to design and demonstrate an effective and efficien toptically transparent, high-gain, lightweight, conformal X-band antenna array that is integrated with the solar panels of a CubeSat. The targeted demonstration is for a Near Earth Network (NEN)radio at X-band, but the design can be easilyscaled to other network radios for higher frequencies. ISAAC is a less expensive and more flexible design for communication systemscompared to a deployed dish antenna or the existing integrated solar panel antenna design.

  18. An improved Marching Cube algorithm for 3D data segmentation

    Science.gov (United States)

    Masala, G. L.; Golosio, B.; Oliva, P.

    2013-03-01

    The marching cube algorithm is one of the most popular algorithms for isosurface triangulation. It is based on a division of the data volume into elementary cubes, followed by a standard triangulation inside each cube. In the original formulation, the marching cube algorithm is based on 15 basic triangulations and a total of 256 elementary triangulations are obtained from the basic ones by rotation, reflection, conjugation, and combinations of these operations. The original formulation of the algorithm suffers from well-known problems of connectivity among triangles of adjacent cubes, which has been solved in various ways. We developed a variant of the marching cube algorithm that makes use of 21 basic triangulations. Triangles of adjacent cubes are always well connected in this approach. The output of the code is a triangulated model of the isosurface in raw format or in VRML (Virtual Reality Modelling Language) format. Catalogue identifier: AENS_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AENS_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 147558 No. of bytes in distributed program, including test data, etc.: 26084066 Distribution format: tar.gz Programming language: C. Computer: Pentium 4, CPU 3.2 GHz and 3.24 GB of RAM (2.77 GHz). Operating system: Tested on several Linux distribution, but generally works in all Linux-like platforms. RAM: Approximately 2 MB Classification: 6.5. Nature of problem: Given a scalar field μ(x,y,z) sampled on a 3D regular grid, build a discrete model of the isosurface associated to the isovalue μIso, which is defined as the set of points that satisfy the equation μ(x,y,z)=μIso. Solution method: The proposed solution is an improvement of the Marching Cube algorithm, which approximates the isosurface using a set of

  19. Bootstrap-Based Inference for Cube Root Consistent Estimators

    DEFF Research Database (Denmark)

    Cattaneo, Matias D.; Jansson, Michael; Nagasawa, Kenichi

    This note proposes a consistent bootstrap-based distributional approximation for cube root consistent estimators such as the maximum score estimator of Manski (1975) and the isotonic density estimator of Grenander (1956). In both cases, the standard nonparametric bootstrap is known to be inconsis......This note proposes a consistent bootstrap-based distributional approximation for cube root consistent estimators such as the maximum score estimator of Manski (1975) and the isotonic density estimator of Grenander (1956). In both cases, the standard nonparametric bootstrap is known...

  20. Compressed Data Cube for Approximate OLAP Query Processing

    Institute of Scientific and Technical Information of China (English)

    冯玉; 王珊

    2002-01-01

    Approximate query processing has emerged as an approach to dealing with thehuge data volume and complex queries in the environment of data warehouse. In this paper,we present a novel method that provides approximate answers to OLAP queries. Our methodis based on building a compressed (approximate) data cube by a clustering technique and usingthis compressed data cube to provide answers to queries directly, so it improves the performanceof the queries. We also provide the algorithm of the OLAP queries and the confidence intervalsof query results. An extensive experimental study with the OLAP council benchmark showsthe effectiveness and scalability of our cluster-based approach compared to sampling.

  1. Temperature Development during Hardening of Large Concrete Cubes

    DEFF Research Database (Denmark)

    Sørensen, Eigil V.; Burcharth, Hans Falk

    The purpose ofthe project is to verify ifthermal cracking will occur in large unreinforced concrete cubes due to large temperature differences during hardening o f the concrete. The first part o f the project is to numerically simulate the temperature development during hardening, evaluate the risk...... of thermally induced crackingunder varying execution conditions, and verify the temperature calculations by caJTying out measurements in situ. The cubes are cast and cured under marine environmental conditions in the north western part of Spain and are to serve as coastal proteetion in a harbour under...

  2. Temperature Development during Hardening of Large Concrete Cubes

    DEFF Research Database (Denmark)

    Sørensen, Eigil V.; Burcharth, Hans Falk

    The purpose ofthe project is to verify ifthermal cracking will occur in large unreinforced concrete cubes due to large temperature differences during hardening o f the concrete. The first part o f the project is to numerically simulate the temperature development during hardening, evaluate the risk...... of thermally induced cracking under varying execution conditions, and verify the temperature calculations by carrying out measurements in situ. The cubes are cast and cured under marine environmental conditions in the north western part of Spain and are to serve as coastal proteetion in a harbour under...

  3. Integrated CubeSat ADACS with Reaction Wheels and Star Tracker Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The MAI-400SS Space Sextant is a precision attitude determination and control system for CubeSats and Nanosats. The MAI-400SS enables future CubeSat missions with...

  4. CubeSat Power Management Controller and Solar Array Articulation System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The CubeSat platform represents a valuable architecture from which to develop satellite capabilities, payloads and technologies. However, CubeSat spacecraft must be...

  5. The IceCube Neutrino Observatory VI: Neutrino Oscillations, Supernova Searches, Ice Properties

    OpenAIRE

    The IceCube Collaboration

    2011-01-01

    Atmospheric neutrino oscillations with DeepCore; Supernova detection with IceCube and beyond; Study of South Pole ice transparency with IceCube flashers; Submitted papers to the 32nd International Cosmic Ray Conference, Beijing 2011.

  6. Solar Electric Propulsion CubeSat Bus for Deep Space Missions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — As electronics continue to shrink in size, the capabilities of CubeSats continues to expand. CubeSats can now perform a wide range of sensing and telecommunications...

  7. 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.

  8. Multipurpose optic-electronic autocollimators for measuring deformations of the axle with a millimeter wave range radiotelescope

    Science.gov (United States)

    Konyakhin, Igor; Molev, Fedor; Konyakhin, Alexey; Li, Renpu

    2015-02-01

    The improved autocollimators for measuring angular deformations of the large constructions as support tube of mirror and elevation axle of the radio telescopes are analyzed. Two new types of the reflector for autocollimator are researched. The first type of the reflectors is the tetrahedral reflector with flat reflecting sides and invariant axis. The autocollimator with tetrahedral reflector is used for the measuring 3-D deformations as roll, pitch and yaw angular deviations. The second type of the reflector is the composition of the anamorphic wedge system and ordinary cube-corner retroreflector. This reflector generates the narrow beam, as result the work distance and the range of measurement of the roll angle increase. Technical characteristics of the experimental setups of new reflectors are presented. Features of the tetrahedral reflector and anamorphic system as the reflectors for multipurpose autocollimator are discussed.

  9. Bone grafting in four-corner mid-carpal fusion.

    Science.gov (United States)

    McBride, T J; Jewell, D P A; Deshmukh, S C

    2012-01-01

    Four-corner fusion is an accepted surgical treatment for established SLAC and SNAC wrist. We describe a technique of bone grafting to be used in conjunction with any of the standard fusion techniques. A step by step, illustrated approach allows the easy placement of an autograft which is in contact with all surfaces of the bones involved in the fusion.

  10. Cut Costs! Not Corners! The Helping Hand Series.

    Science.gov (United States)

    Nash, Claire

    This guide is intended to help employees in the hotel and catering industry to cut costs without cutting corners by showing more concern to cost containment measures and increasing personal productivity. The first three sections discuss the importance of the individual employee's behavior to overall cost containment in the workplace, and different…

  11. Processing Academic Language through Four Corners Vocabulary Chart Applications

    Science.gov (United States)

    Smith, Sarah; Sanchez, Claudia; Betty, Sharon; Davis, Shiloh

    2016-01-01

    4 Corners Vocabulary Charts (FCVCs) are explored as a multipurpose vehicle for processing academic language in a 5th-grade classroom. FCVCs typically display a vocabulary word, an illustration of the word, synonyms associated with the word, a sentence using a given vocabulary word, and a definition of the term in students' words. The use of…

  12. An Efficient Implementation of the Head-Corner Parser

    CERN Document Server

    Van Noord, G

    1997-01-01

    This paper describes an efficient and robust implementation of a bi-directional, head-driven parser for constraint-based grammars. This parser is developed for the OVIS system: a Dutch spoken dialogue system in which information about public transport can be obtained by telephone. After a review of the motivation for head-driven parsing strategies, and head-corner parsing in particular, a non-deterministic version of the head-corner parser is presented. A memoization technique is applied to obtain a fast parser. A goal-weakening technique is introduced which greatly improves average case efficiency, both in terms of speed and space requirements. I argue in favor of such a memoization strategy with goal-weakening in comparison with ordinary chart-parsers because such a strategy can be applied selectively and therefore enormously reduces the space requirements of the parser, while no practical loss in time-efficiency is observed. On the contrary, experiments are described in which head-corner and left-corner pa...

  13. Study on electrostatic resonance of nanoprisms with sharp corners

    Science.gov (United States)

    Chan, Wai Soen; Ng, Ka Ki; Yu, Kin Wah

    2015-03-01

    We have studied the electrostatic resonance of metal nanoprisms with sharp corners numerically. We consider an infinite metal cylinder with polygonal base, e.g. square. The incident electric field lies in the plane of cross-section of the cylinder. Yu and co-workers proposed Green's function formalism (GFF) to numerically calculate the electric potential and field distribution in plasmonic systems. We will adopt the scheme to demonstrate the effect of sharp corners, particularly on the effect of electrostatic resonance spectrum, as in the spectral analysis proposed by Bergman and Milton. Hetherington and Thorpe investigated the conductivity of a sheet containing dilute inclusion with sharp corners, they made use of a conformal mapping approach to calculate the conductivity from circular inclusions. Helsing, McPhedran and Milton also investigated the optical properties of a metamaterial lattice with inclusions having sharp corners. We study the possibility of improving numerical accuracy by combining the conformal mapping approach and GFF. We may extend similar approach to investigate the properties of plasmonic systems, for examples nanoboties and nanostars.

  14. Spectrum of an Elliptic Free Fermionic Corner Transfer Matrix Hamiltonian

    CERN Document Server

    Cuerno, R

    1993-01-01

    The eigenvalues of the Corner Transfer Matrix Hamiltonian associated to the elliptic $R$ matrix of the eight vertex free fermion model are computed in the anisotropic case for magnetic field smaller than the critical value. An argument based on generating functions is given, and the results are checked numerically. The spectrum consists of equally spaced levels.

  15. Schoolyard Corner Society: Relating Membership to Reactive and Proactive Aggressiveness

    Science.gov (United States)

    Storksen, Svein; Idsoe, Thormod; Roland, Erling

    2011-01-01

    This study investigated whether secondary schools in Norway had deviant subcultures, which could be labelled "schoolyard corner society", and how gender and age were related to membership. We also studied levels of reactive and proactive aggressiveness in students, and the relationship between these types of aggressiveness and participation in…

  16. Four Corners Television History: Gallipoli and the Fall of Singapore

    Directory of Open Access Journals (Sweden)

    Kevin Blackburn

    2007-08-01

    Full Text Available This article analyses how the Australian current affairs programme, Four Corners, which follows a style modelled on the BBC programme Panorama, has represented Australian military history in two of its programmes, Gallipoli: The Fatal Shore and No Prisoners on Australian deserters at the fall of Singapore. Chris Masters was the reporter on both programmes. These historical documentaries claim to investigate Australian Anzac mythology. Four Corners is noted for its rigorous pursuit of issues in current affairs. Programmes construct argument that the journalists steadfastly pursue in order to ‘expose the truth’. Rather than neutrally representing both sides of a debate, the programmes tend to take the side that the journalists perceive to be in the public interest. Examining how Four Corners has applied its own style of investigative journalism to the Anzac mythology is explored by outlining whether the programmes follow Ken Burn’s ideas of documentary-makers as ‘tribal story-teller’ crafting stories that uphold national identity or Bill Nichols’ view that documentary is an argument that is representative of reality rather than reflects reality. Examining the history of Gallipoli and the fall of Singapore in the Four Corners programmes tends suggest that the journalists working on the programmes preferred to reaffirm the assumptions of the Anzac legend, but attack or ignore historians and evidence that questions it. The programmes appear to be a mixture of Burns’s and Nichols’ ideas of documentary making.

  17. COMPUTATION OF NONEQUILIBRIUM HYPERSONIC FLOW OVER CONCAVE CORNERS

    Institute of Scientific and Technical Information of China (English)

    Taehoon Park; You-lan Zhu

    2001-01-01

    This paper is devoted to computation of hypersonic flow of air with chemical reactions over concave corners. A technique combining smooth transformation of domain and implicit difference methods is used to overcome numerical difficulties associated with the lack of resolution behind the shock and near the body. The implicit treatment of right hand side terms is also an important part of our method.

  18. 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.

  19. 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.

  20. 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)

  1. The IceCube Neutrino Observatory: instrumentation and online systems

    Science.gov (United States)

    Aartsen, M. G.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Ahrens, M.; Altmann, D.; Andeen, K.; Anderson, T.; Ansseau, I.; Anton, G.; Archinger, M.; Argüelles, C.; Auer, R.; Auffenberg, J.; Axani, S.; Baccus, J.; Bai, X.; Barnet, S.; Barwick, S. W.; Baum, V.; Bay, R.; Beattie, K.; Beatty, J. J.; Becker Tjus, J.; Becker, K.-H.; Bendfelt, T.; BenZvi, S.; Berley, D.; Bernardini, E.; Bernhard, A.; Besson, D. Z.; Binder, G.; Bindig, D.; Bissok, M.; Blaufuss, E.; Blot, S.; Boersma, D.; Bohm, C.; Börner, M.; Bos, F.; Bose, D.; Böser, S.; Botner, O.; Bouchta, A.; Braun, J.; Brayeur, L.; Bretz, H.-P.; Bron, S.; Burgman, A.; Burreson, C.; Carver, T.; Casier, M.; Cheung, E.; Chirkin, D.; Christov, A.; Clark, K.; Classen, L.; Coenders, S.; Collin, G. H.; Conrad, J. M.; Cowen, D. F.; Cross, R.; Day, C.; Day, M.; de André, J. P. A. M.; De Clercq, C.; del Pino Rosendo, E.; Dembinski, H.; De Ridder, S.; Descamps, F.; Desiati, P.; de Vries, K. D.; de Wasseige, G.; de With, M.; DeYoung, T.; Díaz-Vélez, J. C.; di Lorenzo, V.; Dujmovic, H.; Dumm, J. P.; Dunkman, M.; Eberhardt, B.; Edwards, W. R.; Ehrhardt, T.; Eichmann, B.; Eller, P.; Euler, S.; Evenson, P. A.; Fahey, S.; Fazely, A. R.; Feintzeig, J.; Felde, J.; Filimonov, K.; Finley, C.; Flis, S.; Fösig, C.-C.; Franckowiak, A.; Frère, M.; Friedman, E.; Fuchs, T.; Gaisser, T. K.; Gallagher, J.; Gerhardt, L.; Ghorbani, K.; Giang, W.; Gladstone, L.; Glauch, T.; Glowacki, D.; Glüsenkamp, T.; Goldschmidt, A.; Gonzalez, J. G.; Grant, D.; Griffith, Z.; Gustafsson, L.; Haack, C.; Hallgren, A.; Halzen, F.; Hansen, E.; Hansmann, T.; Hanson, K.; Haugen, J.; Hebecker, D.; Heereman, D.; Helbing, K.; Hellauer, R.; Heller, R.; Hickford, S.; Hignight, J.; Hill, G. C.; Hoffman, K. D.; Hoffmann, R.; Hoshina, K.; Huang, F.; Huber, M.; Hulth, P. O.; Hultqvist, K.; In, S.; Inaba, M.; Ishihara, A.; Jacobi, E.; Jacobsen, J.; Japaridze, G. S.; Jeong, M.; Jero, K.; Jones, A.; Jones, B. J. P.; Joseph, J.; Kang, W.; Kappes, A.; Karg, T.; Karle, A.; Katz, U.; Kauer, M.; Keivani, A.; Kelley, J. L.; Kemp, J.; Kheirandish, A.; Kim, J.; Kim, M.; Kintscher, T.; Kiryluk, J.; Kitamura, N.; Kittler, T.; Klein, S. R.; Kleinfelder, S.; Kleist, M.; Kohnen, G.; Koirala, R.; Kolanoski, H.; Konietz, R.; Köpke, L.; Kopper, C.; Kopper, S.; Koskinen, D. J.; Kowalski, M.; Krasberg, M.; Krings, K.; Kroll, M.; Krückl, G.; Krüger, C.; Kunnen, J.; Kunwar, S.; Kurahashi, N.; Kuwabara, T.; Labare, M.; Laihem, K.; Landsman, H.; Lanfranchi, J. L.; Larson, M. J.; Lauber, F.; Laundrie, A.; Lennarz, D.; Leich, H.; Lesiak-Bzdak, M.; Leuermann, M.; Lu, L.; Ludwig, J.; Lünemann, J.; Mackenzie, C.; Madsen, J.; Maggi, G.; Mahn, K. B. M.; Mancina, S.; Mandelartz, M.; Maruyama, R.; Mase, K.; Matis, H.; Maunu, R.; McNally, F.; McParland, C. P.; Meade, P.; Meagher, K.; Medici, M.; Meier, M.; Meli, A.; Menne, T.; Merino, G.; Meures, T.; Miarecki, S.; Minor, R. H.; Montaruli, T.; Moulai, M.; Murray, T.; Nahnhauer, R.; Naumann, U.; Neer, G.; Newcomb, M.; Niederhausen, H.; Nowicki, S. C.; Nygren, D. R.; Obertacke Pollmann, A.; Olivas, A.; O'Murchadha, A.; Palczewski, T.; Pandya, H.; Pankova, D. V.; Patton, S.; Peiffer, P.; Penek, Ö.; Pepper, J. A.; Pérez de los Heros, C.; Pettersen, C.; Pieloth, D.; Pinat, E.; Price, P. B.; Przybylski, G. T.; Quinnan, M.; Raab, C.; Rädel, L.; Rameez, M.; Rawlins, K.; Reimann, R.; Relethford, B.; Relich, M.; Resconi, E.; Rhode, W.; Richman, M.; Riedel, B.; Robertson, S.; Rongen, M.; Roucelle, C.; Rott, C.; Ruhe, T.; Ryckbosch, D.; Rysewyk, D.; Sabbatini, L.; Sanchez Herrera, S. E.; Sandrock, A.; Sandroos, J.; Sandstrom, P.; Sarkar, S.; Satalecka, K.; Schlunder, P.; Schmidt, T.; Schoenen, S.; Schöneberg, S.; Schukraft, A.; Schumacher, L.; Seckel, D.; Seunarine, S.; Solarz, M.; Soldin, D.; Song, M.; Spiczak, G. M.; Spiering, C.; Stanev, T.; Stasik, A.; Stettner, J.; Steuer, A.; Stezelberger, T.; Stokstad, R. G.; Stößl, A.; Ström, R.; Strotjohann, N. L.; Sulanke, K.-H.; Sullivan, G. W.; Sutherland, M.; Taavola, H.; Taboada, I.; Tatar, J.; Tenholt, F.; Ter-Antonyan, S.; Terliuk, A.; Tešić, G.; Thollander, L.; Tilav, S.; Toale, P. A.; Tobin, M. N.; Toscano, S.; Tosi, D.; Tselengidou, M.; Turcati, A.; Unger, E.; Usner, M.; Vandenbroucke, J.; van Eijndhoven, N.; Vanheule, S.; van Rossem, M.; van Santen, J.; Vehring, M.; Voge, M.; Vogel, E.; Vraeghe, M.; Wahl, D.; Walck, C.; Wallace, A.; Wallraff, M.; Wandkowsky, N.; Weaver, Ch.; Weiss, M. J.; Wendt, C.; Westerhoff, S.; Wharton, D.; Whelan, B. J.; Wickmann, S.; Wiebe, K.; Wiebusch, C. H.; Wille, L.; Williams, D. R.; Wills, L.; Wisniewski, P.; Wolf, M.; Wood, T. R.; Woolsey, E.; Woschnagg, K.; Xu, D. L.; Xu, X. W.; Xu, Y.; Yanez, J. P.; Yodh, G.; Yoshida, S.; Zoll, M.

    2017-03-01

    The IceCube Neutrino Observatory is a cubic-kilometer-scale high-energy neutrino detector built into the ice at the South Pole. Construction of IceCube, the largest neutrino detector built to date, was completed in 2011 and enabled the discovery of high-energy astrophysical neutrinos. We describe here the design, production, and calibration of the IceCube digital optical module (DOM), the cable systems, computing hardware, and our methodology for drilling and deployment. We also describe the online triggering and data filtering systems that select candidate neutrino and cosmic ray events for analysis. Due to a rigorous pre-deployment protocol, 98.4% of the DOMs in the deep ice are operating and collecting data. IceCube routinely achieves a detector uptime of 99% by emphasizing software stability and monitoring. Detector operations have been stable since construction was completed, and the detector is expected to operate at least until the end of the next decade.

  2. Neutrino Physics with the IceCube Detector

    Energy Technology Data Exchange (ETDEWEB)

    IceCube Collaboration; Kiryluk, Joanna; Kiryluk, Joanna

    2008-06-11

    IceCube is a cubic kilometer neutrino telescope under construction at the South Pole.The primary goal is to discover astrophysical sources of high energy neutrinos.We describe the detector and present results on atmospheric muon neutrinos from2006 data collected with nine detector strings.

  3. Waring’s problem for cubes and biquadrates

    Institute of Scientific and Technical Information of China (English)

    陆鸣皋; 余红兵

    1995-01-01

    Let r(n) denote the number of representations of n as the sums of 5 cubes and 3 biquadra-tes of natural numbers. Then for all sufficiently large n, one has r(n)(?)n17/12, which is the expected order of magnitude of r(n).

  4. Sublimation-Induced Shape Evolution of Silver Cubes

    KAUST Repository

    Ding, Yong

    2009-12-18

    The heat is on: Surface sublimation and shape transformation of silver cubes, enclosed by {100} surfaces and about 100nm in size, are examined by in situ transmission electron microscopy (see picture). High-index surfaces, such as {110}, of face-centered cubic metals are more stable when the temperature is close to the melting point.

  5. Temporal Processing in Bistable Perception of the Necker Cube.

    Science.gov (United States)

    Wernery, Jannis; Atmanspacher, Harald; Kornmeier, Jürgen; Candia, Victor; Folkers, Gerd; Wittmann, Marc

    2015-02-01

    Perception of ambiguous figures is unstable and alternates repeatedly between possible interpretations. Some approaches to explaining this phenomenon have, so far, assumed low-level bottom-up mechanisms like adaptation and mutual inhibition of underlying neural assemblies. In contrast, less precise top-down approaches assume high-level attentional control mechanisms generalised across sensory modalities. In the current work we focused on specific aspects of the top-down approach. In a first study we used dwell times (periods of transiently stable percepts) and the parameters of dwell time distribution functions to compare the dynamics of perceptual alternations between visual (Necker cube) and auditory ambiguity (verbal transformation effect). In a second study we compared the endogenous alternation dynamics of the Necker cube with parameters from two attention tasks with different regimes of temporal dynamics. The first attention task (d2) is characterised by endogenous self-paced dynamics, similar to the dynamics underlying perceptual alternations of ambiguous figures, and we found clear correlations between dwell time parameters (Necker cube) and processing speed (d2 task). The temporal dynamics of the second (go/no-go) attention task, in contrast, are exogenously governed by the stimulus protocol, and we found no statistically significant correlation with the Necker cube data. Our results indicate that both perceptual instability and higher-level attentional tasks are linked to endogenous brain dynamics on a global coordinating level beyond sensory modalities.

  6. Event selection with a Random Forest in IceCube

    Energy Technology Data Exchange (ETDEWEB)

    Ruhe, Tim [TU, Dortmund (Germany); Collaboration: IceCube-Collaboration

    2011-07-01

    The Random Forest method is a multivariate algorithm that can be used for classification and regression respectively. The Random Forest implemented in the RapidMiner learning environment has been used for training and validation on data and Monte Carlo simulations of the IceCube neutrino telescope. Latest results are presented.

  7. New Formula for Stability of Cube Armoured Roundheads

    DEFF Research Database (Denmark)

    Maciñeira, Enrique; Burcharth, Hans F.

    2007-01-01

    Design of armour for rubble mound breakwater roundheads constitutes in many cases a problem due to the limitation of available data and guidelines. The objective of the paper is to present the results of a comprehensive model test study on the stability of cube armoured roundheads, resulting...... in a new stability formula...

  8. The software invention cube: A classification scheme for software inventions

    NARCIS (Netherlands)

    Bergstra, J.A.; Klint, P.

    2008-01-01

    The patent system protects inventions. The requirement that a software invention should make ‘a technical contribution’ turns out to be untenable in practice and this raises the question, what constitutes an invention in the realm of software. The authors developed the Software Invention Cube (SWIC)

  9. Neutrino Physics with the IceCube Detector

    OpenAIRE

    Kiryluk, Joanna; IceCube Collaboration

    2008-01-01

    IceCube is a cubic kilometer neutrino telescope under construction at the South Pole. The primary goal is to discover astrophysical sources of high energy neutrinos. We describe the detector and present results on atmospheric muon neutrinos from 2006 data collected with nine detector strings.

  10. New Formula for Stability of Cube Armoured Roundheads

    DEFF Research Database (Denmark)

    Maciñeira, Enrique; Burcharth, Hans F.

    2009-01-01

    The paper presents a new formula for the stability of cube armoured roundheads. The formula is based on physical model tests in Aalborg University which both long crested and short crested waves of different wave steepness were used. The slope of the radius of the head were varied in order...

  11. AURA - A radio frequency extension to IceCube

    CERN Document Server

    Ruckman, L

    2008-01-01

    The excellent radio frequency transparency of cold polar ice, combined with the coherent Cherenkov emission produced by neutrino-induced showers when viewed at wavelengths longer than a few centimeters, has spurred considerable interest in a large-scale radio-wave neutrino detector array. The AURA (Askaryan Under-ice Radio Array) experimental effort, within the IceCube collaboration, seeks to take advantage of the opportunity presented by IceCube drilling through 2010 to establish the radio frequency technology needed to achieve 100-1000 km^3 effective volumes. In the 2006-2007 Austral summer 3 deep in-ice radio frequency (RF) clusters were deployed at depths of 1300m and 300m on top of the IceCube strings. Additional 3 clusters will be deployed in the Austral summer of 2008-2009. Verification and calibration results from the current deployed clusters are presented, and the detector design and performances are discussed. Augmentation of IceCube with large-scale 1000km^3sr radio and acoustic arrays would exten...

  12. A Governance Roadmap and Framework for EarthCube

    Science.gov (United States)

    Governance Steering Committee, EarthCube

    2013-04-01

    EarthCube is a process and an outcome, established to transform the conduct of research through the development of community-guided cyberinfrastructure for the Geosciences as the prototype for potential deployment across all domain sciences. EarthCube aims to create a knowledge management system and infrastructure that integrates all Earth system and human dimensions data in an open transparent, and inclusive manner. EarthCube requires broad community participation in concept, framework, and implementation and must not be hindered by rigid preconceptions. We discovered widely varying interpretations, expectations, and assumptions about governance among EarthCube participants. Our definition of governance refers to the processes, structure and organizational elements that determine, within an organization or system of organizations, how power is exercised, how stakeholders have their say, how decisions are made, and how decision makers are held accountable. We have learned, from historic infrastructure case studies, background research on governance and from community feedback during this roadmap process, that other types of large-scale, complex infrastructures, including the Internet, have no central control, administration, or management. No national infrastructure that we examined is governed by a single entity, let alone a single governance archetype. Thus we feel the roadmap process must accommodate a governance system or system of systems that may have a single governing entity, particularly at the start, but can evolve into a collective of governing bodies as warranted, in order to be successful. A fast-track process during Spring, 2012 culminated in a Governance Roadmap delivered to an NSF-sponsored charrette in June with an aggressive timetable to define and implement a governance structure to enable the elements of EarthCube to become operational expeditiously. Our goal is to help ensure the realization of this infrastructure sooner, more efficiently, and

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. EarthCube Activities: Community Engagement Advancing Geoscience Research

    Science.gov (United States)

    Kinkade, D.

    2015-12-01

    Our ability to advance scientific research in order to better understand complex Earth systems, address emerging geoscience problems, and meet societal challenges is increasingly dependent upon the concept of Open Science and Data. Although these terms are relatively new to the world of research, Open Science and Data in this context may be described as transparency in the scientific process. This includes the discoverability, public accessibility and reusability of scientific data, as well as accessibility and transparency of scientific communication (www.openscience.org). Scientists and the US government alike are realizing the critical need for easy discovery and access to multidisciplinary data to advance research in the geosciences. The NSF-supported EarthCube project was created to meet this need. EarthCube is developing a community-driven common cyberinfrastructure for the purpose of accessing, integrating, analyzing, sharing and visualizing all forms of data and related resources through advanced technological and computational capabilities. Engaging the geoscience community in EarthCube's development is crucial to its success, and EarthCube is providing several opportunities for geoscience involvement. This presentation will provide an overview of the activities EarthCube is employing to entrain the community in the development process, from governance development and strategic planning, to technical needs gathering. Particular focus will be given to the collection of science-driven use cases as a means of capturing scientific and technical requirements. Such activities inform the development of key technical and computational components that collectively will form a cyberinfrastructure to meet the research needs of the geoscience community.

  18. 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.

  19. 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...

  20. 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.

  1. 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)

  2. 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.

  3. Evaluation of the Impact of an Additive Manufacturing Enhanced CubeSat Architecture on the CubeSat Development Process

    Science.gov (United States)

    2016-09-15

    fabrication method ideally suited to low- quantity, highly customized builds, leading to interest in the application of AM techniques to satellite...x List of Acronyms and Definitions ...................................................................................... xi...of Acronyms and Definitions 1U 10 cm x 10 cm x 10cm, unit volume size for CubeSats 3D Three-Dimensional ABS Acrylonitrile Butadiene Styrene ABS-M20

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. A Slice Algorithm for Corners and Hilbert-Poincaré Series of Monomial Ideals

    DEFF Research Database (Denmark)

    Roune, Bjarke Hammersholt

    2010-01-01

    We present an algorithm for computing the corners of a monomial ideal. The corners are a set of multidegrees that support the numerical information of a monomial ideal such as Betti numbers and Hilbert-Poincaré series. We show an experiment using corners to compute Hilbert-Poincaré series...

  9. 40 CFR 81.121 - Four Corners Interstate Air Quality Control Region.

    Science.gov (United States)

    2010-07-01

    ... Quality Control Regions § 81.121 Four Corners Interstate Air Quality Control Region. The Four Corners Interstate Air Quality Control Region (Colorado-New Mexico-Utah) has been revised to consist of the... 40 Protection of Environment 17 2010-07-01 2010-07-01 false Four Corners Interstate Air...

  10. Models, modules and abelian groups in memory of A.L.S.Corner

    CERN Document Server

    Goldsmith, Brendan

    2008-01-01

    This is a memorial volume dedicated to A. L. S. Corner, previously Professor in Oxford, who published important results on algebra, especially on the connections of modules with endomorphism algebras. The volume contains refereed contributions which are related to the work of Corner.It contains also an unpublished extended paper of Corner himself. A memorial volume with important contributions related to algebra.

  11. IMPROVED REAL-TIME SCAN MATCHING USING CORNER FEATURES

    Directory of Open Access Journals (Sweden)

    H. A. Mohamed

    2016-06-01

    Full Text Available The automation of unmanned vehicle operation has gained a lot of research attention, in the last few years, because of its numerous applications. The vehicle localization is more challenging in indoor environments where absolute positioning measurements (e.g. GPS are typically unavailable. Laser range finders are among the most widely used sensors that help the unmanned vehicles to localize themselves in indoor environments. Typically, automatic real-time matching of the successive scans is performed either explicitly or implicitly by any localization approach that utilizes laser range finders. Many accustomed approaches such as Iterative Closest Point (ICP, Iterative Matching Range Point (IMRP, Iterative Dual Correspondence (IDC, and Polar Scan Matching (PSM handles the scan matching problem in an iterative fashion which significantly affects the time consumption. Furthermore, the solution convergence is not guaranteed especially in cases of sharp maneuvers or fast movement. This paper proposes an automated real-time scan matching algorithm where the matching process is initialized using the detected corners. This initialization step aims to increase the convergence probability and to limit the number of iterations needed to reach convergence. The corner detection is preceded by line extraction from the laser scans. To evaluate the probability of line availability in indoor environments, various data sets, offered by different research groups, have been tested and the mean numbers of extracted lines per scan for these data sets are ranging from 4.10 to 8.86 lines of more than 7 points. The set of all intersections between extracted lines are detected as corners regardless of the physical intersection of these line segments in the scan. To account for the uncertainties of the detected corners, the covariance of the corners is estimated using the extracted lines variances. The detected corners are used to estimate the transformation parameters

  12. Improved Real-Time Scan Matching Using Corner Features

    Science.gov (United States)

    Mohamed, H. A.; Moussa, A. M.; Elhabiby, M. M.; El-Sheimy, N.; Sesay, Abu B.

    2016-06-01

    The automation of unmanned vehicle operation has gained a lot of research attention, in the last few years, because of its numerous applications. The vehicle localization is more challenging in indoor environments where absolute positioning measurements (e.g. GPS) are typically unavailable. Laser range finders are among the most widely used sensors that help the unmanned vehicles to localize themselves in indoor environments. Typically, automatic real-time matching of the successive scans is performed either explicitly or implicitly by any localization approach that utilizes laser range finders. Many accustomed approaches such as Iterative Closest Point (ICP), Iterative Matching Range Point (IMRP), Iterative Dual Correspondence (IDC), and Polar Scan Matching (PSM) handles the scan matching problem in an iterative fashion which significantly affects the time consumption. Furthermore, the solution convergence is not guaranteed especially in cases of sharp maneuvers or fast movement. This paper proposes an automated real-time scan matching algorithm where the matching process is initialized using the detected corners. This initialization step aims to increase the convergence probability and to limit the number of iterations needed to reach convergence. The corner detection is preceded by line extraction from the laser scans. To evaluate the probability of line availability in indoor environments, various data sets, offered by different research groups, have been tested and the mean numbers of extracted lines per scan for these data sets are ranging from 4.10 to 8.86 lines of more than 7 points. The set of all intersections between extracted lines are detected as corners regardless of the physical intersection of these line segments in the scan. To account for the uncertainties of the detected corners, the covariance of the corners is estimated using the extracted lines variances. The detected corners are used to estimate the transformation parameters between the

  13. 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.

  14. Large networks of artificial radar reflectors to monitor land subsidence in natural lowlying coastal areas

    Science.gov (United States)

    Tosi, Luigi; Strozzi, Tazio; Teatini, Pietro

    2014-05-01

    Deltas, lagoons, estuaries are generally much prone to land subsidence. They are also very sensitive to land lowering due to their small elevation with respect to the mean sea level, also in view of the expected eustatic sea rise due to climate changes. Land subsidence can be presently monitored with an impressive accuracy by Persistent Scatterer Interferometry (PSI) on the large megacities that are often located on lowlying coastlands, e.g., Shanghai (China) on the Yangtze River delta, Dhaka (Bangladesh) on the Gange River delta, New Orleans (Louisiana) on the Mississippi river delta. Conversely, the land movements of the portions of these transitional coastlands where natural environments still persist are very challenging to be measured. The lack of anthropogenic structures strongly limits the use of PSI and the difficult accessibility caused by the presence of marshlands, tidal marshes, channels, and ponds yield traditional methodologies, such as levelling and GPS, both time-consuming and costly. In this contribution we present a unique experimental study aimed at using a large network of artificial radar reflectors to measure land subsidence in natural coastal areas. The test site is the 60-km long, 10-15 km wide lagoon of Venice, Italy, where previous PSI investigations revealed the lack of radar reflectors in large portions of the northern and southern lagoon basins (e.g., Teatini et al., 2011). A network of 57 trihedral corner reflectors (TCRs) were established between the end of 2006 and the beginning of 2007 and monitored by ENVISAT ASAR and TerraSAR-X acquisitions covering the time period from 2007 to 2011 (Strozzi et al., 2012). The application has provided general important insights on the possibility of controlling land subsidence using this approach. For example: (i) relatively small-size (from 0.5 to 1.0 m edge length) and cheap (few hundred euros) TCRs suffice to be clearly detectable from the radar sensors because of the low backscattering

  15. Edge and corner identification for tracking the line of sight Edge and corner identification for tracking the line of sight

    OpenAIRE

    María S Orozco; Uwe Jasnoch; Oscar Eduardo Ruiz Salguero

    2005-01-01

    This article presents an edge-corner detector, implemented in the realm of the GEIST project (an Computer Aided Touristic Information System) to extract the information of straight edges and their intersections (image corners) from camera-captured (real world) and computer-generated images (from the database of Historical Monuments, using ob- server position and orientation data). Camera and computer-generated images are processed for reduction of detail, skeletonization and corner-edge detec...

  16. Neutrino oscillation parameter sampling with MonteCUBES

    Science.gov (United States)

    Blennow, Mattias; Fernandez-Martinez, Enrique

    2010-01-01

    We present MonteCUBES ("Monte Carlo Utility Based Experiment Simulator"), a software package designed to sample the neutrino oscillation parameter space through Markov Chain Monte Carlo algorithms. MonteCUBES makes use of the GLoBES software so that the existing experiment definitions for GLoBES, describing long baseline and reactor experiments, can be used with MonteCUBES. MonteCUBES consists of two main parts: The first is a C library, written as a plug-in for GLoBES, implementing the Markov Chain Monte Carlo algorithm to sample the parameter space. The second part is a user-friendly graphical Matlab interface to easily read, analyze, plot and export the results of the parameter space sampling. Program summaryProgram title: MonteCUBES (Monte Carlo Utility Based Experiment Simulator) Catalogue identifier: AEFJ_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEFJ_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public Licence No. of lines in distributed program, including test data, etc.: 69 634 No. of bytes in distributed program, including test data, etc.: 3 980 776 Distribution format: tar.gz Programming language: C Computer: MonteCUBES builds and installs on 32 bit and 64 bit Linux systems where GLoBES is installed Operating system: 32 bit and 64 bit Linux RAM: Typically a few MBs Classification: 11.1 External routines: GLoBES [1,2] and routines/libraries used by GLoBES Subprograms used:Cat Id ADZI_v1_0, Title GLoBES, Reference CPC 177 (2007) 439 Nature of problem: Since neutrino masses do not appear in the standard model of particle physics, many models of neutrino masses also induce other types of new physics, which could affect the outcome of neutrino oscillation experiments. In general, these new physics imply high-dimensional parameter spaces that are difficult to explore using classical methods such as multi-dimensional projections and minimizations, such as those

  17. Formative Evaluation for a Healthy Corner Store Initiative in Pitt County, North Carolina: Engaging Stakeholders for a Healthy Corner Store Initiative, Part 2

    Directory of Open Access Journals (Sweden)

    Katherine K. Lawton, MPH

    2013-07-01

    Full Text Available Introduction We examined the feasibility of increasing access to healthful food in corner stores to inform a Communities Putting Prevention to Work (CPPW initiative by engaging stakeholders (corner store owners and customers in a formative evaluation. Methods Qualitative interviews were conducted with corner store owners and managers (n = 11. Customer intercept surveys (n = 179 were also conducted with customers of 9 stores. Corner stores were located in rural food deserts (municipalities without a chain supermarket and in low-income, urban municipalities in eastern North Carolina. Interviews were transcribed verbatim and double-coded. Qualitative themes related to feasibility of increasing access to healthful foods were extracted. Shopping patterns of rural and urban customers were compared by using t tests. Results Corner store owners were willing to stock more healthful foods, but they perceived that customer demand for these foods was low. Rural customers reported more frequently shopping at corner stores than urban customers and more frequently stated that the reason they do not eat more fruits and vegetables is that the stores in which they shop do not sell them. Most customers reported they would be very or somewhat likely to purchase fresh produce at a corner store. Conclusion Corner stores may be an important source of food for rural and low-income residents and thus a good place in which to intervene. The results of this formative evaluation were used to plan and evaluate a CPPW healthy corner store initiative.

  18. Effect of contact angle on the orientation, stability, and assembly of dense floating cubes.

    Science.gov (United States)

    Daniello, Robert; Khan, Kashan; Donnell, Michael; Rothstein, Jonathan P

    2014-02-01

    In this paper, the effect of contact angle, density, and size on the orientation, stability, and assembly of floating cubes was investigated. All the cubes tested were more dense than water. Floatation occurred as a result of capillary stresses induced by deformation of the air-water interface. The advancing contact angle of the bare acrylic cubes was measured to be 85°. The contact angle of the cubes was increased by painting the cubes with a commercially available superhydrophobic paint to reach an advancing contact angle of 150°. Depending on their size, density, and contact angle, the cubes were observed to float in one of three primary orientations: edge up, vertex up, and face up. An experimental apparatus was built such that the sum of the gravitational force, buoyancy force, and capillary forces could be measured using a force transducer as a function of cube position as it was lowered through the air-water interface. Measurements showed that the maximum capillary forces were always experienced for the face up orientation. However, when floatation was possible in the vertex up orientation, it was found to be the most stable cube orientation because it had the lowest center of gravity. A series of theoretical predictions were performed for the cubes floating in each of the three primary orientations to calculate the net force on the cube. The theoretical predictions were found to match the experimental measurements well. A cube stability diagram of cube orientation as a function of cube contact angle and size was prepared from the predictions of theory and found to match the experimental observations quite well. The assembly of cubes floating face up and vertex up were also studied for assemblies of two, three, and many cubes. Cubes floating face up were found to assemble face-to-face and form regular square lattice patterns with no free interface between cubes. Cubes floating vertex up were found to assemble in a variety of different arrangements

  19. Universality of corner entanglement in conformal field theories

    CERN Document Server

    Bueno, Pablo; Witczak-Krempa, William

    2015-01-01

    We study the contribution to the entanglement entropy of (2+1)-dimensional conformal field theories coming from a sharp corner in the entangling surface. This contribution is encoded in a function $a(\\theta)$ of the corner opening angle, and was recently proposed as a measure of the degrees of freedom in the underlying CFT. We show that the ratio $a(\\theta)/C_T$ , where $C_T$ is the central charge in the stress tensor correlator, is an almost universal quantity for a broad class of theories including various higher-curvature holographic models, free scalars and fermions, and Wilson-Fisher fixed points of the $O(N)$ models with $N=1,2,3$. Strikingly, the agreement between these different theories becomes exact in the limit $\\theta\\rightarrow \\pi$, where the entangling surface approaches a smooth curve. We thus conjecture that the corresponding ratio is universal for general CFTs in three dimensions.

  20. An improved TLD with Harris corner and color moment

    Science.gov (United States)

    Li, Ling; Liu, Kai; Cheng, Fei; Bao, Di

    2017-02-01

    Video tracking is a main field of computer vision, and TLD algorithm plays a key role in long-term tracking. However, the original TLD ignores the color features of patch in detection, and tracks the common points from grid, then, the tracking accuracy is limited to both of them. This paper presents a novel TLD algorithm with Harris corner and color moment to overcome this drawback. Instead of tracking common points, we screen more important points utilizing Harris corner to reject a half patches, these points are better able to show the object's textural features. In addition, the color moment classifier replaces patch variance to reduce the errors of detection. The classifier compares mine-dimensional color moment vectors so that it can keep the TLD's stable speed. Experiment has proved that our TLD tracks a more reliable position and higher ability without affecting the speed.

  1. Communities Putting Prevention to Work: The Healthy Corner Store Initiative

    Centers for Disease Control (CDC) Podcasts

    2013-07-18

    This podcast is an interview with Dr. Stephanie Jilcott Pitts, Associate Professor in the Department of Public Health at East Carolina University. Dr. Pitts answers questions about her study involving a healthy corner store initiative in North Carolina.  Created: 7/18/2013 by Preventing Chronic Disease (PCD), National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 7/18/2013.

  2. Suppressing rippling with minimized corner rounding through OPC fragmentation optimization

    Science.gov (United States)

    Wang, Jingyu; Wei, Alexander; Wilkinson, William; Chen, Norman

    2016-10-01

    As technology shrinks, the requirements placed on the post-OPC solution become so exacting that even small residual optical effects are significant. Simultaneously minimizing rippling and corner rounding cannot be accom- plished in parallel in wafer patterning especially when complex asymmetric pixelated sources are used. While either effect can be moderated by accurate application of optical proximity correction, they are both charac- teristic of unfiltered diffraction due to asymmetric illumination or design geometry and will remain inherent. Corrections that over emphasize reduced corner-rounding necessarily sacrifice edge convergence, resulting in a standing wave or unacceptable rippling along an entire edge. OPC can be used to reduce the magnitude of this rippling, but fragment placing is extremely critical. In this paper, we discuss optimized OPC fragmentation that offers balanced consideration to suppressing rippling and minimizing corner rounding. Specifically, we correlate design shapes with simulated post-OPC contours to account for design geometry-dependent rippling signature given existing illumination conditions. In contrast to adaptive fragmentation that relies on multiple iterations of simulation of intensity extrema redistribution, our method predicts the optimum contour as allowed by process and fragments the mask accordingly. The maximum imaging curvature resolvable by process coupled with the rippling signature, gives rise to the exact locations of the inflection points of the wafer contour. From there we achieve the best correction results by segmenting edges at the inflection points.

  3. Corner block list representation and its application with boundary constraints

    Institute of Scientific and Technical Information of China (English)

    HONG Xianlong; MA Yuchun; DONG Sheqin; CAI Yici; Chung-Kuan Cheng; GU Jun

    2004-01-01

    Floorplanning is a critical phase in physical design of VLSI circuits. The stochastic optimization method is widely used to handle this NP-hard problem. The key to the floorplanning algorithm based on stochastic optimization is to encode the floorplan structure properly. In this paper, corner block list (CBL)-a new efficient topological representation for non-slicing floorplan-is proposed with applications to VLSI floorplan.Given a corner block list, it takes only linear time to construct the floorplan. In floorplanning of typical VLSI design, some blocks are required to satisfy some constraints in the final packing. Boundary constraint is one kind of those constraints to pack some blocks along the pre-specified boundaries of the final chip so that the blocks are easier to be connected to certain I/O pads. We implement the boundary constraint algorithm for general floorplan by extending CBL. Our contribution is to find the necessary and sufficient characterization of the blocks along the boundary represented by CBL. We can check the boundary constraints by scanning the intermediate solutions in linear time during the simulated annealing process and fix the corner block list in case the constraints are violated. The experiment results are demonstrated by several examples of MCNC benchmarks and the performance is remarkable.

  4. 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.

  5. 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...

  6. Neutrino searches with the IceCube telescope

    Science.gov (United States)

    Aguilar, Juan A.

    2013-04-01

    The IceCube Neutrino Observatory is an array of 5,160 photomultipliers (PMTs) deployed on 86 strings at 1.5-2.5 km depth within the ice at the South Pole. The main goal of the IceCube experiment is the detection of an astrophysical neutrino signal. In this contribution we present the results of the point source analysis on the data taken from April 2008 to May 2011, when three detector configurations were operated: the 40-string configuration (IC-40), the 59-string configuration (IC-59) and the 79-string configuration (IC-79). No significant excess indicative of point sources of neutrinos has been found, and we present upper limits for an E-2 muon neutrino flux for a list of candidate sources. For the first time these limits start to reach 10-12 TeV cm s in some parts of the sky.

  7. A new physics interpretation of the IceCube data

    Science.gov (United States)

    Illana, José Ignacio; Masip, Manuel; Meloni, Davide

    2015-05-01

    IceCube has recently observed 37 events of TeV-PeV energies. The angular distribution, with a strong preference for downgoing directions, the spectrum, and the small muon to shower ratio in the data cannot be accommodated assuming standard interactions of atmospheric neutrinos. We obtain an excellent fit, however, if a diffuse flux of ultrahigh energy (cosmogenic) neutrinos experiences collisions where only a small fraction of the energy is transferred to the target nucleon. We show that consistent models of TeV gravity or other non-Wilsonian completions of the standard model provide cross sections with these precise features. An increased statistics could clearly distinguish our scenario from the one assumed by IceCube (a diffuse flux of astrophysical neutrinos with a ∝E-2 spectrum) and establish the need for new physics in the interpretation of the data.

  8. IceCube and the Development of Neutrino Astronomy

    CERN Document Server

    CERN. Geneva

    2016-01-01

    Abstract: IceCube's discovery of a diffuse flux of astrophysical neutrinos started a new era of neutrino astronomy.I will review the multiple diffuse analyses in IceCube that observe the astrophysical flux, and what each can tell us. Then I will focus on spatial analyses that aim to identify the sources of such astrophysical neutrinos. This will be followed by an attempt to reconcile all results to draw a coherent picture that is the state of neutrino astronomy. Current plans for a streamlined real-time alert system to promote multi-messenger observations, and future plans of new detectors at the South Pole will be discussed to map out a path for discovering the first high-energy neutrino source in the sky.

  9. Data Cubes Integration in Spatial OLAP for Agricultural Commodities

    Science.gov (United States)

    Putri, A. I.; Sitanggang, I. S.

    2017-03-01

    Ministry of Agriculture Indonesia collects data of agricultural commodities in Indonesia in the annual period. Agricultural commodities data include food crops, horticulture, plantations, and livestock. The data are available in the spreadsheet format. This study developed data cubes for food crops, plantations, and livestock using the galaxy schema of data warehouse and integrated the data cubes into the SOLAP Horticulture using SpagoBI. SOLAP is useful for data analysis and data visualization. The application displays agricultural commodities data in form of crosstab and chart. This study also developed the location intelligence module that visualizes agricultural commodities data on the map. The system was tested using the black box approach. The result showed that main functions including roll up, drill down, slice, dice, and pivot work properly. This application is expected to enable users to easily obtain data summaries of agricultural commodities.

  10. A spatio-temporal extension to the map cube operator

    Science.gov (United States)

    Alzate, Juan C.; Moreno, Francisco J.; Echeverri, Jaime

    2012-09-01

    OLAP (On Line Analytical Processing) is a set of techniques and operators to facilitate the data analysis usually stored in a data warehouse. In this paper, we extend the functionality of an OLAP operator known as Map Cube with the definition and incorporation of a function that allows the formulation of spatio-temporal queries. For example, consider a data warehouse about crimes that includes data about the places where the crimes were committed. Suppose we want to find and visualize the trajectory (a trajectory is just the path that an object follows through space as a function of time) of the crimes of a suspect beginning with his oldest crime and ending with his most recent one. In order to meet this requirement, we extend the Map Cube operator.

  11. ATLAS Virtual Visit IceCube-02-10-2014

    CERN Multimedia

    2014-01-01

    Building on last year’s success, high-school students and teachers in five countries will have the unique opportunity to interact live with researchers at the ATLAS and CMS experiments at CERN and researchers at the IceCube Neutrino Observatory in Antarctica. This virtual visit is the second event in the series, “Bringing Frontier Science to Schools”, that aims to connect the two laboratories, supported by the Open Discovery Space (ODS) project. ODS brings millions of educational resources directly into school classrooms, and empowers teachers to build their schools’ digital libraries, join lively communities of peers to share best practices, and connect their schools virtually with the world’s best research centres, museums and libraries. - See more at: http://atlas-live-virtual-visit.web.cern.ch/atlas-live-virtual-visit/2014/IceCube-2014.html#sthash.l523hihH.dpuf

  12. IceCube and GRB neutrinos propagating in quantum spacetime

    Science.gov (United States)

    Amelino-Camelia, Giovanni; Barcaroli, Leonardo; D'Amico, Giacomo; Loret, Niccoló; Rosati, Giacomo

    2016-10-01

    Two recent publications have reported intriguing analyses, tentatively suggesting that some aspects of IceCube data might be manifestations of quantum-gravity-modified laws of propagation for neutrinos. We here propose a strategy of data analysis which has the advantage of being applicable to several alternative possibilities for the laws of propagation of neutrinos in a quantum spacetime. In all scenarios here of interest one should find a correlation between the energy of an observed neutrino and the difference between the time of observation of that neutrino and the trigger time of a GRB. We select accordingly some GRB-neutrino candidates among IceCube events, and our data analysis finds a rather strong such correlation. This sort of study naturally lends itself to the introduction of a "false alarm probability", which for our analysis we estimate conservatively to be of 1%. We therefore argue that our findings should motivate a vigorous program of investigation following the strategy here advocated.

  13. IceCube and GRB neutrinos propagating in quantum spacetime

    CERN Document Server

    Amelino-Camelia, Giovanni; D'Amico, Giacomo; Loret, Niccoló; Rosati, Giacomo

    2016-01-01

    Two recent publications have reported intriguing analyses, tentatively suggesting that some aspects of IceCube data might be manifestations of quantum-gravity-modified laws of propagation for neutrinos. We here propose a strategy of data analysis which has the advantage of being applicable to several alternative possibilities for the laws of propagation of neutrinos in a quantum spacetime. In all scenarios here of interest one should find a correlation between the energy of an observed neutrino and the difference between the time of observation of that neutrino and the trigger time of a GRB. We select accordingly some GRB-neutrino candidates among IceCube events, and our data analysis finds a rather strong such correlation. This sort of studies naturally lends itself to the introduction of a "false alarm probability", which for our analysis we estimate conservatively to be of 1%. We therefore argue that our findings should motivate a vigorous program of investigation following the strategy here advocated.

  14. Blazar origin of some IceCube events

    CERN Document Server

    Miranda, Luis Salvador; Sahu, Sarira

    2015-01-01

    Recently ANTARES collaboration presented a time dependent analysis to a selected number of flaring blazars to look for upward going muon events produced from the charge current interaction of the muon neutrinos. We use the same list of flaring blazars to look for possible positional correlation with the IceCube neutrino events. We observed that six FSRQs and two BL Lac objects from the list are within the error circles of eight IceCube events. We also observed that three FSRQs are within the error circles of more than one event. In the context of photohadronic model we propose that these neutrinos are produced within the nuclear region of the blazar where Fermi accelerated high energy protons interact with the background synchrotron/SSC photons.

  15. Short-baseline neutrino oscillations, Planck, and IceCube

    CERN Document Server

    Cherry, John F; Shoemaker, Ian M

    2016-01-01

    We examine a framework with light new physics, which couples to the Standard Model only via neutrino mixing. Taking the hints from the short-baseline anomalies seriously and combining them with modern cosmological data and recent IceCube measurements, we obtain surprisingly effective constraints on the hidden force: keV $\\lesssim M \\lesssim0.3$ GeV for the mediator mass and $g_{h}>10^{-6}-10^{-3}$ for the coupling constant. Flavor equilibration between the hidden and active neutrinos can be delayed until temperatures of $\\sim 1$ MeV, but not below $\\sim 100$ keV. This scenario can be tested with next-generation Cosmic Microwave Background, IceCube, and oscillation experiments.

  16. Calibration and Characterization of the IceCube Photomultiplier Tube

    CERN Document Server

    Abbasi, R; Abu-Zayyad, T; Adams, J; Aguilar, J A; Ahlers, M; Andeen, K; Auffenberg, J; Bai, X; Baker, M; Barwick, S W; Bay, R; Alba, J L Bazo; Beattie, K; Beatty, J J; Bechet, S; Becker, J K; Becker, K -H; Benabderrahmane, M L; Berdermann, J; Berghaus, P; Berley, D; Bernardini, E; Bertrand, D; Besson, D Z; Bissok, M; Blaufuss, E; Boersma, D J; Bohm, C; Botner, O; Bradley, L; Braun, J; Buitink, S; Carson, M; Chirkin, D; Christy, B; Clem, J; Cohen, S; Colnard, C; Cowen, D F; D'Agostino, M V; Danninger, M; De Clercq, C; Demirörs, L; Depaepe, O; Descamps, F; Desiati, P; de Vries-Uiterweerd, G; DeYoung, T; Díaz-Vélez, J C; Dreyer, J; Dumm, J P; Duvoort, M R; Ehrlich, R; Eisch, J; Ellsworth, R W; Engdegård, O; Euler, S; Evenson, P A; Fadiran, O; Fazely, A R; Feusels, T; Filimonov, K; Finley, C; Foerster, M M; Fox, B D; Franckowiak, A; Franke, R; Gaisser, T K; Gallagher, J; Ganugapati, R; Geisler, M; Gerhardt, L; Gladstone, L; Goldschmidt, A; Goodman, J A; Grant, D; Griesel, T; Groß, A; Grullon, S; Gunasingha, R M; Gurtner, M; Ha, C; Hallgren, A; Halzen, F; Han, K; Hanson, K; Hasegawa, Y; Haugen, J; Helbing, K; Herquet, P; Hickford, S; Hill, G C; Hoffman, K D; Homeier, A; Hoshina, K; Hubert, D; Huelsnitz, W; Hülß, J -P; Hulth, P O; Hultqvist, K; Hussain, S; Imlay, R L; Inaba, M; Ishihara, A; Jacobsen, J; Japaridze, G S; Johansson, H; Joseph, J M; Kampert, K -H; Kappes, A; Karg, T; Karle, A; Kelley, J L; Kemming, N; Kenny, P; Kiryluk, J; Kislat, F; Kitamura, N; Klein, S R; Knops, S; Kohnen, G; Kolanoski, H; Köpke, L; Koskinen, D J; Kowalski, M; Kowarik, T; Krasberg, M; Krings, T; Kroll, G; Kuehn, K; Kuwabara, T; Labare, M; Lafebre, S; Laihem, K; Landsman, H; Lauer, R; Laundrie, A; Lehmann, R; Lennarz, D; Lünemann, J; Madsen, J; Majumdar, P; Maruyama, R; Mase, K; Matis, H S; Matusik, M; Meagher, K; Merck, M; Mészáros, P; Meures, T; Middell, E; Milke, N; Miyamoto, H; Montaruli, T; Morse, R; Movit, S M; Nahnhauer, R; Nam, J W; Naumann, U; Nießen, P; Nygren, D R; Odrowski, S; Olivas, A; Olivo, M; Ono, M; Panknin, S; Paul, L; Heros, C Pérez de los; Petrovic, J; Piegsa, A; Pieloth, D; Pohl, A C; Porrata, R; Posselt, J; Price, P B; Prikockis, M; Przybylski, G T; Rawlins, K; Redl, P; Resconi, E; Rhode, W; Ribordy, M; Rizzo, A; Robl, P; Rodrigues, J P; Roth, P; Rothmaier, F; Rott, C; Roucelle, C; Rutledge, D; Ruzybayev, B; Ryckbosch, D; Sander, H -G; Sandstrom, P; Sarkar, S; Schatto, K; Schlenstedt, S; Schmidt, T; Schneider, D; Schukraft, A; Schultes, A; Schulz, O; Schunck, M; Seckel, D; Semburg, B; Seo, S H; Sestayo, Y; Seunarine, S; Silvestri, A; Slipak, A; Spiczak, G M; Spiering, C; Stamatikos, M; Stanev, T; Stephens, G; Stezelberger, T; Stokstad, R G; Stoyanov, S; Strahler, E A; Straszheim, T; Sullivan, G W; Swillens, Q; Taboada, I; Tamburro, A; Tarasova, O; Tepe, A; Ter-Antonyan, S; Terranova, C; Tilav, S; Toale, P A; Tosi, D; Turcan, D; van Eijndhoven, N; Vandenbroucke, J; Van Overloop, A; van Santen, J; Voigt, B; Wahl, D; Walck, C; Waldenmaier, T; Wallraff, M; Walter, M; Wendt, C; Westerhoff, S; Whitehorn, N; Wiebe, K; Wiebusch, C H; Wikström, G; Williams, D R; Wischnewski, R; Wissing, H; Woschnagg, K; Xu, C; Xu, X W; Yodh, G; Yoshida, S; Zarzhitsky, P

    2010-01-01

    Over 5,000 PMTs are being deployed at the South Pole to compose the IceCube neutrino observatory. Many are placed deep in the ice to detect Cherenkov light emitted by the products of high-energy neutrino interactions, and others are frozen into tanks on the surface to detect particles from atmospheric cosmic ray showers. IceCube is using the 10-inch diameter R7081-02 made by Hamamatsu Photonics. This paper describes the laboratory characterization and calibration of these PMTs before deployment. PMTs were illuminated with pulses ranging from single photons to saturation level. Parameterizations are given for the single photoelectron charge spectrum and the saturation behavior. Time resolution, late pulses and afterpulses are characterized. Because the PMTs are relatively large, the cathode sensitivity uniformity was measured. The absolute photon detection efficiency was calibrated using Rayleigh-scattered photons from a nitrogen laser. Measured characteristics are discussed in the context of their relevance t...

  17. 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...

  18. 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)

  19. Dellingr- A Path to Compelling Science with CubeSats

    Science.gov (United States)

    Johnson, M.; Bonalsky, T.; Chornay, D.; Clagett, C.; Cudmore, A.; Ericsson, A.; Hesh, S.; Jones, S.; Kepko, L.; Rodriguez, J.; Sittler, E.; Starin, S.; Santos, L.; Sheikh, S.; Uribe, P.; Zesta, E.

    2015-10-01

    Advancements in the capabilities of miniaturized systems are dramatically increasing interest in achieving science from CubeSats. The Dellingr project targets this interest. It will realize compelling science from a 6U spacecraft while developing human and spacecraft systems required to cost-efficiently deliver small satellites capable of reliably achieving mission objectives in divers environments—from low earth orbit to challenging radiation and thermal environments associated with lunar and planetary missions.

  20. Streamlining CubeSat Solar Panel Fabrication Processes

    OpenAIRE

    Sandberg, Ariel; Smith, Timothy

    2016-01-01

    A critical facet of CubeSat fabrication is solar panel characterization and assembly. Though capable of producing flight quality solar subsystems, traditional methods of solar panel fabrication contain intrinsic inefficiencies and inconsistencies that compromise the subsystem’s overall reliability. Taking Michigan Exploration Laboratory’s (MXL) heritage solar panel procedures as a case study, this investigation sought to streamline the solar panel fabrication process to increase its yield, co...

  1. Lunar and Lagrangian Point L1 L2 CubeSat Communication and Navigation Considerations

    Science.gov (United States)

    Schaire, Scott; Wong, Yen F.; Altunc, Serhat; Bussey, George; Shelton, Marta; Folta, Dave; Gramling, Cheryl; Celeste, Peter; Anderson, Mile; Perrotto, Trish; hide

    2017-01-01

    CubeSats have grown in sophistication to the point that relatively low-cost mission solutions could be undertaken for planetary exploration. There are unique considerations for lunar and L1/L2 CubeSat communication and navigation compared with low earth orbit CubeSats. This paper explores those considerations as they relate to the Lunar IceCube Mission. The Lunar IceCube is a CubeSat mission led by Morehead State University with participation from NASA Goddard Space Flight Center, Jet Propulsion Laboratory, the Busek Company and Vermont Tech. It will search for surface water ice and other resources from a high inclination lunar orbit. Lunar IceCube is one of a select group of CubeSats designed to explore beyond low-earth orbit that will fly on NASA’s Space Launch System (SLS) as secondary payloads for Exploration Mission (EM) 1. Lunar IceCube and the EM-1 CubeSats will lay the groundwork for future lunar and L1/L2 CubeSat missions. This paper discusses communication and navigation needs for the Lunar IceCube mission and navigation and radiation tolerance requirements related to lunar and L1/L2 orbits. Potential CubeSat radios and antennas for such missions are investigated and compared. Ground station coverage, link analysis, and ground station solutions are also discussed. This paper will describe modifications in process for the Morehead ground station, as well as further enhancements of the Morehead ground station and NASA Near Earth Network (NEN) that are being considered. The potential NEN enhancements include upgrading current NEN Cortex receiver with Forward Error Correction (FEC) Turbo Code, providing X-band uplink capability, and adding ranging options. The benefits of ground station enhancements for CubeSats flown on NASA Exploration Missions (EM) are presented. This paper also describes how the NEN may support lunar and L1/L2 CubeSats without any enhancements. In addition, NEN is studying other initiatives to better support the CubeSat community

  2. IceCube systematic errors investigation: Simulation of the ice

    Energy Technology Data Exchange (ETDEWEB)

    Resconi, Elisa; Wolf, Martin [Max-Planck-Institute for Nuclear Physics, Heidelberg (Germany); Schukraft, Anne [RWTH, Aachen University (Germany)

    2010-07-01

    IceCube is a neutrino observatory for astroparticle and astronomy research at the South Pole. It uses one cubic kilometer of Antartica's deepest ice (1500 m-2500 m in depth) to detect Cherenkov light, generated by charged particles traveling through the ice, with an array of phototubes encapsulated in glass pressure spheres. The arrival time as well as the charge deposited of the detected photons represent the base measurements that are used for track and energy reconstruction of those charged particles. The optical properties of the deep antarctic ice vary from layer to layer. Measurements of the ice properties and their correct modeling in Monte Carlo simulation is then of primary importance for the correct understanding of the IceCube telescope behavior. After a short summary about the different methods to investigate the ice properties and to calibrate the detector, we show how the simulation obtained by using this information compares to the measured data and how systematic errors due to uncertain ice properties are determined in IceCube.

  3. Measurement of atmospheric neutrino oscillations with IceCube.

    Science.gov (United States)

    Aartsen, M G; Abbasi, R; Abdou, Y; Ackermann, M; Adams, J; Aguilar, J A; Ahlers, M; Altmann, D; Auffenberg, J; Bai, X; Baker, M; Barwick, S W; Baum, V; Bay, R; Beatty, J J; Bechet, S; Becker Tjus, J; Becker, K-H; Bell, M; Benabderrahmane, M L; Benzvi, S; Berdermann, J; Berghaus, P; Berley, D; Bernardini, E; Bernhard, A; Bertrand, D; Besson, D Z; Binder, G; Bindig, D; Bissok, M; Blaufuss, E; Blumenthal, J; Boersma, D J; Bohaichuk, S; Bohm, C; Bose, D; Böser, S; Botner, O; Brayeur, L; Bretz, H-P; Brown, A M; Bruijn, R; Brunner, J; Carson, M; Casey, J; Casier, M; Chirkin, D; Christov, A; Christy, B; Clark, K; Clevermann, F; Coenders, S; Cohen, S; Cowen, D F; Cruz Silva, A H; Danninger, M; Daughhetee, J; Davis, J C; De Clercq, C; De Ridder, S; Desiati, P; de With, M; DeYoung, T; Díaz-Vélez, J C; Dunkman, M; Eagan, R; Eberhardt, B; Eisch, J; Ellsworth, R W; Euler, S; Evenson, P A; Fadiran, O; Fazely, A R; Fedynitch, A; Feintzeig, J; Feusels, T; Filimonov, K; Finley, C; Fischer-Wasels, T; Flis, S; Franckowiak, A; Franke, R; Frantzen, K; Fuchs, T; Gaisser, T K; Gallagher, J; Gerhardt, L; Gladstone, L; Glüsenkamp, T; Goldschmidt, A; Golup, G; Gonzalez, J G; Goodman, J A; Góra, D; Grandmont, D T; Grant, D; Groß, A; Ha, C; Haj Ismail, A; Hallen, P; Hallgren, A; Halzen, F; Hanson, K; Heereman, D; Heinen, D; Helbing, K; Hellauer, R; Hickford, S; Hill, G C; Hoffman, K D; Hoffmann, R; Homeier, A; Hoshina, K; Huelsnitz, W; Hulth, P O; Hultqvist, K; Hussain, S; Ishihara, A; Jacobi, E; Jacobsen, J; Jagielski, K; Japaridze, G S; Jero, K; Jlelati, O; Kaminsky, B; Kappes, A; Karg, T; Karle, A; Kelley, J L; Kiryluk, J; Kislat, F; Kläs, J; Klein, S R; Köhne, J-H; Kohnen, G; Kolanoski, H; Köpke, L; Kopper, C; Kopper, S; Koskinen, D J; Kowalski, M; Krasberg, M; Krings, K; Kroll, G; Kunnen, J; Kurahashi, N; Kuwabara, T; Labare, M; Landsman, H; Larson, M J; Lesiak-Bzdak, M; Leuermann, M; Leute, J; Lünemann, J; Madsen, J; Maruyama, R; Mase, K; Matis, H S; McNally, F; Meagher, K; Merck, M; Mészáros, P; Meures, T; Miarecki, S; Middell, E; Milke, N; Miller, J; Mohrmann, L; Montaruli, T; Morse, R; Nahnhauer, R; Naumann, U; Niederhausen, H; Nowicki, S C; Nygren, D R; Obertacke, A; Odrowski, S; Olivas, A; Olivo, M; O'Murchadha, A; Palazzo, A; Paul, L; Pepper, J A; Pérez de los Heros, C; Pfendner, C; Pieloth, D; Pinat, E; Pirk, N; Posselt, J; Price, P B; Przybylski, G T; Rädel, L; Rameez, M; Rawlins, K; Redl, P; Reimann, R; Resconi, E; Rhode, W; Ribordy, M; Richman, M; Riedel, B; Rodrigues, J P; Rott, C; Ruhe, T; Ruzybayev, B; Ryckbosch, D; Saba, S M; Salameh, T; Sander, H-G; Santander, M; Sarkar, S; Schatto, K; Scheel, M; Scheriau, F; Schmidt, T; Schmitz, M; Schoenen, S; Schöneberg, S; Schönwald, A; Schukraft, A; Schulte, L; Schulz, O; Seckel, D; Sestayo, Y; Seunarine, S; Sheremata, C; Smith, M W E; Soldin, D; Spiczak, G M; Spiering, C; Stamatikos, M; Stanev, T; Stasik, A; Stezelberger, T; Stokstad, R G; Stößl, A; Strahler, E A; Ström, R; Sullivan, G W; Taavola, H; Taboada, I; Tamburro, A; Tepe, A; Ter-Antonyan, S; Tešić, G; Tilav, S; Toale, P A; Toscano, S; Usner, M; van der Drift, D; van Eijndhoven, N; Van Overloop, A; van Santen, J; Vehring, M; Voge, M; Vraeghe, M; Walck, C; Waldenmaier, T; Wallraff, M; Wasserman, R; Weaver, Ch; Wellons, M; Wendt, C; Westerhoff, S; Whitehorn, N; Wiebe, K; Wiebusch, C H; Williams, D R; Wissing, H; Wolf, M; Wood, T R; Woschnagg, K; Xu, C; Xu, D L; Xu, X W; Yanez, J P; Yodh, G; Yoshida, S; Zarzhitsky, P; Ziemann, J; Zierke, S; Zoll, M

    2013-08-23

    We present the first statistically significant detection of neutrino oscillations in the high-energy regime (>20 GeV) from an analysis of IceCube Neutrino Observatory data collected in 2010 and 2011. This measurement is made possible by the low-energy threshold of the DeepCore detector (~20 GeV) and benefits from the use of the IceCube detector as a veto against cosmic-ray-induced muon background. The oscillation signal was detected within a low-energy muon neutrino sample (20-100 GeV) extracted from data collected by DeepCore. A high-energy muon neutrino sample (100 GeV-10 TeV) was extracted from IceCube data to constrain systematic uncertainties. The disappearance of low-energy upward-going muon neutrinos was observed, and the nonoscillation hypothesis is rejected with more than 5σ significance. In a two-neutrino flavor formalism, our data are best described by the atmospheric neutrino oscillation parameters |Δm(32)(2)|=(2.3(-0.5)(+0.6))×10(-3) eV(2) and sin(2)(2θ(23))>0.93, and maximum mixing is favored.

  4. Calibration and Characterization of the IceCube Photomultiplier Tube

    Energy Technology Data Exchange (ETDEWEB)

    IceCube Collaboration; Abbasi, R.; al., et

    2010-02-11

    Over 5,000 PMTs are being deployed at the South Pole to compose the IceCube neutrino observatory. Many are placed deep in the ice to detect Cherenkov light emitted by the products of high-energy neutrino interactions, and others are frozen into tanks on the surface to detect particles from atmospheric cosmic ray showers. IceCube is using the 10-inch diameter R7081-02 made by Hamamatsu Photonics. This paper describes the laboratory characterization and calibration of these PMTs before deployment. PMTs were illuminated with pulses ranging from single photons to saturation level. Parameterizations are given for the single photoelectron charge spectrum and the saturation behavior. Time resolution, late pulses and afterpulses are characterized. Because the PMTs are relatively large, the cathode sensitivity uniformity was measured. The absolute photon detection efficiency was calibrated using Rayleigh-scattered photons from a nitrogen laser. Measured characteristics are discussed in the context of their relevance to IceCube event reconstruction and simulation efforts.

  5. IceCube: An Instrument for Neutrino Astronomy

    Energy Technology Data Exchange (ETDEWEB)

    IceCube Collaboration; Halzen, F.; Klein, S.

    2010-06-04

    Neutrino astronomy beyond the Sun was first imagined in the late 1950s; by the 1970s, it was realized that kilometer-scale neutrino detectors were required. The first such instrument, IceCube, is near completion and taking data. The IceCube project transforms a cubic kilometer of deep and ultra-transparent Antarctic ice into a particle detector. A total of 5,160 optical sensors are embedded into a gigaton of Antarctic ice to detect the Cherenkov light emitted by secondary particles produced when neutrinos interact with nuclei in the ice. Each optical sensor is a complete data acquisition system, including a phototube, digitization electronics, control and trigger systems and LEDs for calibration. The light patterns reveal the type (flavor) of neutrino interaction and the energy and direction of the neutrino, making neutrino astronomy possible. The scientific missions of IceCube include such varied tasks as the search for sources of cosmic rays, the observation of Galactic supernova explosions, the search for dark matter, and the study of the neutrinos themselves. These reach energies well beyond those produced with accelerator beams.

  6. Decaying Leptophilic Dark Matter at IceCube

    CERN Document Server

    Boucenna, Sofiane M; Mangano, Gianpiero; Miele, Gennaro; Morisi, Stefano; Pisanti, Ofelia; Vitagliano, Edoardo

    2015-01-01

    We present a novel interpretation of IceCube high energy neutrino events (with energy larger than 60 TeV) in terms of an extraterrestrial flux due to two different contributions: a flux originated by known astrophysical sources and dominating IceCube observations up to few hundreds TeV, and a new flux component where the most energetic neutrinos come from the leptophilic three-body decays of dark matter particles with a mass of few PeV. Differently from other approaches, we provide two examples of elementary particle models that do not need fine-tuned tiny coupling constants. Interestingly, we find a slightly better agreement of the theoretical predictions with the IceCube results if the astrophysical flux has a cut-off at about 100 TeV (broken power law). In this case the most energetic part of the spectrum (PeV neutrinos) is due to an extra component such as the decay of a very massive dark matter component. Of course, the low statistics at our disposal still allows for a purely astrophysical origin of the ...

  7. Decaying leptophilic dark matter at IceCube

    Science.gov (United States)

    Boucenna, Sofiane M.; Chianese, Marco; Mangano, Gianpiero; Miele, Gennaro; Morisi, Stefano; Pisanti, Ofelia; Vitagliano, Edoardo

    2015-12-01

    We present a novel interpretation of IceCube high energy neutrino events (with energy larger than 60 TeV) in terms of an extraterrestrial flux due to two different contributions: a flux originated by known astrophysical sources and dominating IceCube observations up to few hundreds TeV, and a new flux component where the most energetic neutrinos come from the leptophilic three-body decays of dark matter particles with a mass of few PeV. Differently from other approaches, we provide two examples of elementary particle models that do not require extremely tiny coupling constants. We find the compatibility of the theoretical predictions with the IceCube results when the astrophysical flux has a cutoff of the order of 100 TeV (broken power law). In this case the most energetic part of the spectrum (PeV neutrinos) is due to an extra component such as the decay of a very massive dark matter component. Due to the low statistics at our disposal we have considered for simplicity the equivalence between deposited and neutrino energy, however such approximation does not affect dramatically the qualitative results. Of course, a purely astrophysical origin of the neutrino flux (no cutoff in energy below the PeV scale—unbroken power law) is still allowed. If future data will confirm the presence of a sharp cutoff above few PeV this would be in favor of a dark matter interpretation.

  8. Can tidal disruption events produce the IceCube neutrinos?

    CERN Document Server

    Dai, Lixin

    2016-01-01

    Powerful jets and outflows generated in tidal disruption events (TDEs) around supermassive black holes have been suggested to be possible sites producing high-energy neutrinos, but it is unclear whether such environment can provide the bulk of the neutrinos detected by the IceCube Observatory. In this work, by considering realistic limits on the non-thermal emission power of a TDE jet and the birth rate of the TDEs with jets pointing towards us, we show that it is hard to use the jetted TDE population to explain the flux and the isotropic arrival directions of the observed TeV-PeV neutrinos. Therefore, TDEs cannot be the dominant sources, unless those without aligned jets can produce wide-angle emission of neutrino particles. Supposing that is the case, we list a few recent jetted and non-jetted TDEs that have the best chance to be detected by IceCube, based on their energetics, distances, and directions. A spatial and temporal association of these predicted events with the IceCube data should provide a decis...

  9. Piecewise linear hypersurfaces using the marching cubes algorithm

    Science.gov (United States)

    Roberts, Jonathan C.; Hill, Steve

    1999-03-01

    Surface visualization is very important within scientific visualization. The surfaces depict a value of equal density (an isosurface) or display the surrounds of specified objects within the data. Likewise, in two dimensions contour plots may be used to display the information. Thus similarly, in four dimensions hypersurfaces may be formed around hyperobjects. These surfaces (or contours) are often formed from a set of connected triangles (or lines). These piecewise segments represent the simplest non-degenerate object of that dimension and are named simplices. In four dimensions a simplex is represented by a tetrahedron, which is also known as a 3- simplex. Thus, a continuous n dimensional surface may be represented by a lattice of connected n-1 dimensional simplices. This lattice of connected simplices may be calculated over a set of adjacent n dimensional cubes, via for example the Marching Cubes Algorithm. We propose that the methods of this local-cell tiling method may be usefully- applied to four dimensions and potentially to N-dimensions. Thus, we organize the large number of traversal cases and major cases; introduce the notion of a sub-case (that enables the large number of cases to be further reduced); and describe three methods for implementing the Marching Cubes lookup table in four-dimensions.

  10. Decaying leptophilic dark matter at IceCube

    Energy Technology Data Exchange (ETDEWEB)

    Boucenna, Sofiane M. [INFN, Laboratori Nazionali di Frascati,C.P. 13, Frascati, I-00044 (Italy); Chianese, Marco [Dipartimento di Fisica, Università di Napoli “Federico II”,Complesso Univ. Monte S. Angelo, Via Cinthia, Napoli, I-80126 (Italy); INFN, Sezione di Napoli, Complesso Univ. Monte S. Angelo,Via Cinthia, Napoli, I-80126 (Italy); Mangano, Gianpiero [INFN, Sezione di Napoli, Complesso Univ. Monte S. Angelo,Via Cinthia, Napoli, I-80126 (Italy); Miele, Gennaro; Morisi, Stefano; Pisanti, Ofelia [Dipartimento di Fisica, Università di Napoli “Federico II”,Complesso Univ. Monte S. Angelo, Via Cinthia, Napoli, I-80126 (Italy); INFN, Sezione di Napoli, Complesso Univ. Monte S. Angelo,Via Cinthia, Napoli, I-80126 (Italy); Vitagliano, Edoardo [Dipartimento di Fisica, Università di Napoli “Federico II”,Complesso Univ. Monte S. Angelo, Via Cinthia, Napoli, I-80126 (Italy)

    2015-12-29

    We present a novel interpretation of IceCube high energy neutrino events (with energy larger than 60 TeV) in terms of an extraterrestrial flux due to two different contributions: a flux originated by known astrophysical sources and dominating IceCube observations up to few hundreds TeV, and a new flux component where the most energetic neutrinos come from the leptophilic three-body decays of dark matter particles with a mass of few PeV. Differently from other approaches, we provide two examples of elementary particle models that do not require extremely tiny coupling constants. We find the compatibility of the theoretical predictions with the IceCube results when the astrophysical flux has a cutoff of the order of 100 TeV (broken power law). In this case the most energetic part of the spectrum (PeV neutrinos) is due to an extra component such as the decay of a very massive dark matter component. Due to the low statistics at our disposal we have considered for simplicity the equivalence between deposited and neutrino energy, however such approximation does not affect dramatically the qualitative results. Of course, a purely astrophysical origin of the neutrino flux (no cutoff in energy below the PeV scale — unbroken power law) is still allowed. If future data will confirm the presence of a sharp cutoff above few PeV this would be in favor of a dark matter interpretation.

  11. Calibration and characterization of the IceCube photomultiplier tube

    Science.gov (United States)

    Abbasi, R.; Abdou, Y.; Abu-Zayyad, T.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Bay, R.; Bazo Alba, J. L.; Beattie, K.; Beatty, J. J.; Bechet, S.; Becker, J. K.; Becker, K.-H.; Benabderrahmane, M. L.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D. Z.; Bissok, M.; Blaufuss, E.; Boersma, D. J.; Bohm, C.; Botner, O.; Bradley, L.; Braun, J.; Buitink, S.; Carson, M.; Chirkin, D.; Christy, B.; Clem, J.; Cohen, S.; Colnard, C.; Cowen, D. F.; D'Agostino, M. V.; Danninger, M.; de Clercq, C.; Demirörs, L.; Depaepe, O.; Descamps, F.; Desiati, P.; de Vries-Uiterweerd, G.; Deyoung, T.; Díaz-Vélez, J. C.; Dreyer, J.; Dumm, J. P.; Duvoort, M. R.; Ehrlich, R.; Eisch, J.; Ellsworth, R. W.; Engdegård, O.; Euler, S.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.; Feusels, T.; Filimonov, K.; Finley, C.; Foerster, M. M.; Fox, B. D.; Franckowiak, A.; Franke, R.; Gaisser, T. K.; Gallagher, J.; Ganugapati, R.; Geisler, M.; Gerhardt, L.; Gladstone, L.; Goldschmidt, A.; Goodman, J. A.; Grant, D.; Griesel, T.; Groß, A.; Grullon, S.; Gunasingha, R. M.; Gurtner, M.; Ha, C.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Hasegawa, Y.; Haugen, J.; Helbing, K.; Herquet, P.; Hickford, S.; Hill, G. C.; Hoffman, K. D.; Homeier, A.; Hoshina, K.; Hubert, D.; Huelsnitz, W.; Hülß, J.-P.; Hulth, P. O.; Hultqvist, K.; Hussain, S.; Imlay, R. L.; Inaba, M.; Ishihara, A.; Jacobsen, J.; Japaridze, G. S.; Johansson, H.; Joseph, J. M.; Kampert, K.-H.; Kappes, A.; Karg, T.; Karle, A.; Kelley, J. L.; Kemming, N.; Kenny, P.; Kiryluk, J.; Kislat, F.; Kitamura, N.; Klein, S. R.; Knops, S.; Kohnen, G.; Kolanoski, H.; Köpke, L.; Koskinen, D. J.; Kowalski, M.; Kowarik, T.; Krasberg, M.; Krings, T.; Kroll, G.; Kuehn, K.; Kuwabara, T.; Labare, M.; Lafebre, S.; Laihem, K.; Landsman, H.; Lauer, R.; Laundrie, A.; Lehmann, R.; Lennarz, D.; Lünemann, J.; Madsen, J.; Majumdar, P.; Maruyama, R.; Mase, K.; Matis, H. S.; Matusik, M.; Meagher, K.; Merck, M.; Mészáros, P.; Meures, T.; Middell, E.; Milke, N.; Miyamoto, H.; Montaruli, T.; Morse, R.; Movit, S. M.; Nahnhauer, R.; Nam, J. W.; Naumann, U.; Nießen, P.; Nygren, D. R.; Odrowski, S.; Olivas, A.; Olivo, M.; Ono, M.; Panknin, S.; Paul, L.; Pérez de Los Heros, C.; Petrovic, J.; Piegsa, A.; Pieloth, D.; Pohl, A. C.; Porrata, R.; Posselt, J.; Price, P. B.; Prikockis, M.; Przybylski, G. T.; Rawlins, K.; Redl, P.; Resconi, E.; Rhode, W.; Ribordy, M.; Rizzo, A.; Robl, P.; Rodrigues, J. P.; Roth, P.; Rothmaier, F.; Rott, C.; Roucelle, C.; Rutledge, D.; Ruzybayev, B.; Ryckbosch, D.; Sander, H.-G.; Sandstrom, P.; Sarkar, S.; Schatto, K.; Schlenstedt, S.; Schmidt, T.; Schneider, D.; Schukraft, A.; Schultes, A.; Schulz, O.; Schunck, M.; Seckel, D.; Semburg, B.; Seo, S. H.; Sestayo, Y.; Seunarine, S.; Silvestri, A.; Slipak, A.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.; Stephens, G.; Stezelberger, T.; Stokstad, R. G.; Stoyanov, S.; Strahler, E. A.; Straszheim, T.; Sullivan, G. W.; Swillens, Q.; Taboada, I.; Tamburro, A.; Tarasova, O.; Tepe, A.; Ter-Antonyan, S.; Terranova, C.; Tilav, S.; Toale, P. A.; Tosi, D.; Turčan, D.; van Eijndhoven, N.; Vandenbroucke, J.; van Overloop, A.; van Santen, J.; Voigt, B.; Wahl, D.; Walck, C.; Waldenmaier, T.; Wallraff, M.; Walter, M.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wiebe, K.; Wiebusch, C. H.; Wikström, G.; Williams, D. R.; Wischnewski, R.; Wissing, H.; Woschnagg, K.; Xu, C.; Xu, X. W.; Yodh, G.; Yoshida, S.; Zarzhitsky, P.; IceCube Collaboration

    2010-06-01

    Over 5000 PMTs are being deployed at the South Pole to compose the IceCube neutrino observatory. Many are placed deep in the ice to detect Cherenkov light emitted by the products of high-energy neutrino interactions, and others are frozen into tanks on the surface to detect particles from atmospheric cosmic ray showers. IceCube is using the 10-in. diameter R7081-02 made by Hamamatsu Photonics. This paper describes the laboratory characterization and calibration of these PMTs before deployment. PMTs were illuminated with pulses ranging from single photons to saturation level. Parameterizations are given for the single photoelectron charge spectrum and the saturation behavior. Time resolution, late pulses and afterpulses are characterized. Because the PMTs are relatively large, the cathode sensitivity uniformity was measured. The absolute photon detection efficiency was calibrated using Rayleigh-scattered photons from a nitrogen laser. Measured characteristics are discussed in the context of their relevance to IceCube event reconstruction and simulation efforts.

  12. Particle shape anisotropy in pickering emulsions: cubes and peanuts.

    Science.gov (United States)

    de Folter, Julius W J; Hutter, Eline M; Castillo, Sonja I R; Klop, Kira E; Philipse, Albert P; Kegel, Willem K

    2014-02-04

    We have investigated the effect of particle shape in Pickering emulsions by employing, for the first time, cubic and peanut-shaped particles. The interfacial packing and orientation of anisotropic microparticles are revealed at the single-particle level by direct microscopy observations. The uniform anisotropic hematite microparticles adsorb irreversibly at the oil-water interface in monolayers and form solid-stabilized o/w emulsions via the process of limited coalescence. Emulsions were stable against further coalescence for at least 1 year. We found that cubes assembled at the interface in monolayers with a packing intermediate between hexagonal and cubic and average packing densities of up to 90%. Local domains displayed densities even higher than theoretically achievable for spheres. Cubes exclusively orient parallel with one of their flat sides at the oil-water interface, whereas peanuts preferentially attach parallel with their long side. Those peanut-shaped microparticles assemble in locally ordered, interfacial particle stacks that may interlock. Indications for long-range capillary interactions were not found, and we hypothesize that this is related to the observed stable orientations of cubes and peanuts that marginalize deformations of the interface.

  13. Moon and Sun shadow observation with IceCube

    Energy Technology Data Exchange (ETDEWEB)

    Bos, Fabian; Tenholt, Frederik; Becker-Tjus, Julia [Theoretische Physik, Ruhr-Universitaet, Bochum (Germany); Westerhoff, Stefan [University of Wisconsin, Madison (United States); Collaboration: IceCube-Collaboration

    2015-07-01

    The analysis of the Moon shadow is a standard method in IceCube to determine the angular resolution and absolute pointing capabilities of the IceCube detector at the geographic South Pole. The Sun has not been used as a calibrator thus far, as its shadow is expected to be influenced by the solar magnetic field, which deflects the cosmic rays near the solar surface. This, on the other hand, provides indirect pieces of information on the magnetic field structure of the Sun. This talk shows a first analysis of the Sun shadow with IceCube data. The analysis is based on the data of the detector configurations with 79 (IC79) and 86 strings (IC86) from 2010 through 2012. To examine the shadows, a binned method is used to compare all events from one on-source with two off-source windows. For the IC40 and IC59 configuration a deficit with a statistical significance of more than 6σ was observed.

  14. Search for Sphalerons: IceCube vs. LHC

    CERN Document Server

    Ellis, John; Spannowsky, Michael

    2016-01-01

    We discuss the observability of neutrino-induced sphaleron transitions in the IceCube detector, encouraged by a recent paper by Tye and Wong (TW), which argued on the basis of a Bloch wave function in the periodic sphaleron potential that such transitions should be enhanced compared to most previous calculations. We calculate the dependence on neutrino energy of the sphaleron transition rate, comparing it to that for conventional neutrino interactions, and we discuss the observability of tau and multi-muon production in sphaleron-induced transitions. We use IceCube 4-year data to constrain the sphaleron rate, finding that it is comparable to the upper limit inferred previously from a recast of an ATLAS search for microscopic black holes at the LHC with $\\sim 3$/fb of collisions at 13 TeV. The IceCube constraint is stronger for a sphaleron barrier height $E_{\\rm Sph} \\gtrsim 9$ TeV, and would be comparable with the prospective LHC sensitivity with 300/fb of data at 14 TeV if $E_{\\rm Sph} \\sim 11$ TeV.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Paraffin Phase Change Material for Maintaining Temperature Stability of IceCube Type of CubeSats in LEO

    Science.gov (United States)

    Choi, Michael K.

    2015-01-01

    The MLA and IFA of the instrument on the IceCube require a 20 C temperature and a thermal stability of +/-1 C. The thermal environment of the ISS orbit for the IceCube is very unstable due to solar beta angles in the -75deg to +75deg range. Additionally the instrument is powered off in every eclipse to conserve electrical power. These two factors cause thermal instability to the MLA and IFA. This paper presents a thermal design of using mini paraffin PCM packs to meet the thermal requirements of these instrument components. With a 31 g mass plus a 30% margin of n-hexadecane, the MLA and IFA are powered on for 32.3 minutes in sunlight at a 0deg beta angle to melt the paraffin. The powered-on time increases to 38 minutes at a 75deg (+/-) beta angle. When the MLA and IFA are powered off, the paraffin freezes.

  20. 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.