WorldWideScience

Sample records for compact shadow shielding

  1. Shadow-Shielding Compensation for Moving Sources Detection

    Science.gov (United States)

    Coulon, Romain; Dumazert, Jonathan

    2017-07-01

    To monitor radioactivity emitted by a vehicle such as a pedestrian, a car, a train, or a truck, radiation portal monitors (RPMs) are commonly employed. It has been noted that these RPM suffer from a shadow-shielding effect when the source is transported by a dense and large vehicle such as a truck or a train. While methods using databases are listed as state of the art, we have developed an approach based on a state model, ensuring a gain in performance and flexibility. This new study presents a technique applied to RPM, efficiently compensating the shadow-shielding effect. A simulation study has been performed to highlight the efficiency and reliability of the method.

  2. Apodized pixel lenses in compact shadow-casting correlators.

    Science.gov (United States)

    Raj, K; Athale, R A

    1995-04-10

    We present a compact two-dimensional shadow-casting correlator that can perform correlation between inputs of size 256 × 256 and a point-spread function of size 32 × 32. A two-dimensional array of mutually incoherent sources is used to encode the point-spread function, and each source is individually steered to improve the light uniformity and the light-utilization efficiency. The geometric optics constraint requires that the shadow region be very close to the input plane. This constraint is removed by the introduction of apodized pixel lenses in the input spatial light modulator. The pixel lenses move the shadow plane to their Fourier plane, and pixel apodization reduces the interchannel cross talk, thereby improving the signal-to-noise ratio. Simulation and experimental results verifying these concepts are presented.

  3. Effect of CSR shielding in the compact linear collider

    CERN Document Server

    Esberg, J; Apsimon, R; Schulte, D

    2014-01-01

    The Drive Beam complex of the Compact Linear Collider must use short bunches with a large charge making beam transport susceptible to unwanted effects of Coherent Synchrotron Radiation emitted in the dipole magnets. We present the effects of transporting the beam within a limited aperture which decreases the magnitude of the CSR wake. The effect, known as CSR shielding, eases the design of key components of the facility.

  4. Response of a Shadow-Shield Whole-Body Counter to a Variety of Physical Phantoms.

    Science.gov (United States)

    Aviv, O; Spitz, H B; Datz, H; Haquin, G; Shamai, Y; Daniely, E; Yungrais, Z; Koch, J

    2017-05-01

    The performance characteristics of a shadow-shield whole-body counter system with an array of four high-resolution germanium detectors using whole-body and organ-specific (lungs, liver, head, knee and thyroid) physical phantoms are described. Detection efficiency and minimum detectable activities for selected radionuclides and several measurement configurations are presented. Results demonstrate that the system meets the requirements for direct radio bioassay and that detection efficiency and minimum detectable activities are similar in magnitude to other whole-body (or organ) counting systems installed in fully shielded structures. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  5. New shielding material development for compact accelerator-driven neutron source

    Directory of Open Access Journals (Sweden)

    Guang Hu

    2017-04-01

    Full Text Available The Compact Accelerator-driven Neutron Source (CANS, especially the transportable neutron source is longing for high effectiveness shielding material. For this reason, new shielding material is researched in this investigation. The component of shielding material is designed and many samples are manufactured. Then the attenuation detection experiments were carried out. In the detections, the dead time of the detector appeases when the proton beam is too strong. To grasp the linear range and nonlinear range of the detector, two currents of proton are employed in Pb attenuation detections. The transmission ratio of new shielding material, polyethylene (PE, PE + Pb, BPE + Pb is detected under suitable current of proton. Since the results of experimental neutrons and γ-rays appear as together, the MCNP and PHITS simulations are applied to assisting the analysis. The new shielding material could reduce of the weight and volume compared with BPE + Pb and PE + Pb.

  6. Results of substitution of the Nal by a Ge detector in a simple shadow shield whole body counter

    Energy Technology Data Exchange (ETDEWEB)

    Sahre, P.; Schoenmuth, T. [Nuclear Engineering and Analytics Inc. Rossendorf, Dresden (Germany); Thieme, K. [Amersham Buchler Ltd. und Co., Braunschweig (Germany)

    1997-12-01

    Since 1976 a whole body counter (WBC) has been used at the Rossendorf Research Centre for measuring the internal contamination of workers. The WBC with the Germanium detector is given schematically and visually. The WBC is a shadow shield type with a tilted chair having only one detector. Table 1 contains the parameters of the WBC. It can be seen that the WBC is a simple counter. Therefore, taking into account the experiences of McCurdy, a lot of improvements were expected form the simple substitution of a HP Germanium detector for a NaI (TI) detector, i.e. despite a decrease in the sensitive detection volume, an enhancement of all quantifiable results (e.g. lower limit of detection and time for analysis of the spectrum) and above all the reliability and automation of nuclide identification were expected. (orig./SR)

  7. Neutron radiation shielding properties of polymer incorporated self compacting concrete mixes.

    Science.gov (United States)

    Malkapur, Santhosh M; Divakar, L; Narasimhan, Mattur C; Karkera, Narayana B; Goverdhan, P; Sathian, V; Prasad, N K

    2017-07-01

    In this work, the neutron radiation shielding characteristics of a class of novel polymer-incorporated self-compacting concrete (PISCC) mixes are evaluated. Pulverized high density polyethylene (HDPE) material was used, at three different reference volumes, as a partial replacement to river sand in conventional concrete mixes. By such partial replacement of sand with polymer, additional hydrogen contents are incorporated in these concrete mixes and their effect on the neutron radiation shielding properties are studied. It has been observed from the initial set of experiments that there is a definite trend of reductions in the neutron flux and dose transmission factor values in these PISCC mixes vis-à-vis ordinary concrete mix. Also, the fact that quite similar enhanced shielding results are recorded even when reprocessed HDPE material is used in lieu of the virgin HDPE attracts further attention. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Thermal and mechanical analysis of the Faraday shield for the Compact Ignition Tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Vesey, R.A.

    1988-02-01

    The antenna for the ion cyclotron resonance heating (ICRH) system of the Compact Ignition Tokamak (CIT) is protected from the plasma environment by a Faraday shield, an array of gas-cooled metallic tubes. The plasma side of the tubes is armored with graphite tiles, which can be either brazed or mechanically attached to the tube. The Faraday shield has been analyzed using finite element codes to model thermal and mechanical responses to typical CIT heating and disruption loads. Four representative materials (Inconel 718, tantalum-10 tungsten, copper alloy C17510, and molybdenum alloy TZM) and several combinations of tube and armor thicknesses were used in the thermal analysis, which revealed that maximum allowable temperatures were not exceeded for any of the four materials considered. The two-dimensional thermal stress analysis indicated Von Mises stresses greater than twice the yield stress for a tube constructed of Inconel 718 (the original design material) for the brazed-graphite design. Analysis of stresses caused by plasma disruption ()rvec J) )times) )rvec B)) loads eliminated the copper and molybdenum alloys as candidate tube materials. Of the four materials considered, tantalum-10 tungsten performed the best for a brazed graphite design, showing acceptable thermal stresses (69% of yield) and disruption stresses (42% of yield). A preliminary thermal analysis of the mechanically attached graphite scheme predicts minimal thermal stresses in the tube. The survivability of the graphite tubes in this scheme is yet to be analyzed. 8 refs., 19 figs., 2 tabs.

  9. Multi-objective optimization of a compact pressurized water nuclear reactor computational model for biological shielding design using innovative materials

    Energy Technology Data Exchange (ETDEWEB)

    Tunes, M.A., E-mail: matheus.tunes@usp.br [Department of Metallurgical and Materials Engineering, Escola Politécnica da Universidade de São Paulo, Av. Prof. Mello Moraes, 2463 – CEP 05508 – 030 São Paulo (Brazil); Oliveira, C.R.E. de, E-mail: cassiano@unm.edu [Department of Nuclear Engineering, The University of New Mexico, Farris Engineering Center, 221, Albuquerque, NM 87131-1070 (United States); Schön, C.G., E-mail: schoen@usp.br [Department of Metallurgical and Materials Engineering, Escola Politécnica da Universidade de São Paulo, Av. Prof. Mello Moraes, 2463 – CEP 05508 – 030 São Paulo (Brazil)

    2017-03-15

    Highlights: • Use of two n-γ transport codes leads to optimized model of compact nuclear reactor. • It was possible to safely reduce both weight and volume of the biological shielding. • Best configuration obtained by using new composites for both γ and n attenuation. - Abstract: The aim of the present work is to develop a computational model of a compact pressurized water nuclear reactor (PWR) to investigate the use of innovative materials to enhance the biological shielding effectiveness. Two radiation transport codes were used: the first one – MCNP – for the PWR design and the GEM/EVENT to simulate (in a 1D slab) the behavior of several materials and shielding thickness on gamma and neutron radiation. Additionally MATLAB Optimization Toolbox was used to provide new geometric configurations of the slab aiming at reducing the volume and weight of the walls by means of a cost/objective function. It is demonstrated in the reactor model that the dose rate outside biological shielding has been reduced by one order of magnitude for the optimized model compared with the initial configuration. Volume and weight of the shielding walls were also reduced. The results indicated that one-dimensional deterministic code to reach an optimized geometry and test materials, combined with a three-dimensional model of a compact nuclear reactor in a stochastic code, is a fast and efficient procedure to test shielding performance and optimization before the experimental assessment. A major outcome of this research is that composite materials (ECOMASS 2150TU96) may replace (with advantages) traditional shielding materials without jeopardizing the nuclear power plant safety assurance.

  10. Radiologic assessment of a self-shield with boron-containing water for a compact medical cyclotron.

    Science.gov (United States)

    Horitsugi, Genki; Fujibuchi, Toshioh; Yamaguchi, Ichiro; Eto, Akihisa; Iwamoto, Yasuo; Hashimoto, Hiromi; Hamada, Seiki; Obara, Satoshi; Watanabe, Hiroshi; Hatazawa, Jun

    2012-07-01

    The cyclotron at our hospital has a self-shield of boron-containing water. The amount of induced radioactivity in the boron-containing water shield of a compact medical cyclotron has not yet been reported. In this study, we measured the photon and neutron dose rates outside the self-shield during cyclotron operation. We estimated the induced radioactivities of the boron-containing water used for the self-shield and then measured them. We estimated the activation of concrete outside the self-shield in the cyclotron laboratory. The thermal neutron flux during cyclotron operation was estimated to be 4.72 × 10(2) cm(-2) s(-1), and the activation of concrete in a cyclotron laboratory was about three orders of magnitude lower than the clearance level of RS-G-1.7 (IAEA). The activity concentration of the boron-containing water did not exceed the concentration limit for radioactive isotopes in drainage in Japan and the exemption level for Basic Safety Standards. Consequently, the boron-containing water is treatable as non-radioactive waste. Neutrons were effectively shielded by the self-shield during cyclotron operation.

  11. Analysis on Filling Ratio and Shield Supporting Pressure for Overburden Movement Control in Coal Mining with Compacted Backfilling

    Directory of Open Access Journals (Sweden)

    Yanli Huang

    2016-12-01

    Full Text Available Since the weight of overburden is sustained by both the backfill body and the unmined solid coal in coal mining with compacted backfilling (CMCB panels, the stress and deformation characteristics of the surrounding rocks in coal mining are radically changed. The overburden movement control mechanism by coordinating with backfill body and shield in CMCB was studied systematically in this paper. Based on the analysis of deformational and structural characteristics of surrounding rock in CMCB panels, the methods of theoretical analysis, numerical simulation and engineering test are employed. The results show that the fracture of the main roof is mainly controlled by the filling ratio φ and is non-correlated to the shield supporting pressure p. However, p has a significant control effect on the deflection of roof within the shield canopy length, and adversely affects the filling ratio. With the increase of the filling ratio of the gob, the maximum sagging of the immediate and the main roofs, the peak front and the influence range of the abutment pressures are gradually reduced. Correspondingly, the stable period of internal pressure of backfill body in the gob is shortened. Engineering practice shows that the sagging of the gob roof, the distribution of the abutment pressure, the distribution of the internal pressure in the backfill body, and the ground surface sagging results obtained by the in-situ measurement are approximately corresponding to the theoretical analysis and numerical simulation results.

  12. Shadow art

    KAUST Repository

    Mitra, Niloy J.

    2009-01-01

    "To them, I said, the truth would be literally nothing but the shadows of the images." - Plato, The Republic Shadow art is a unique form of sculptural art where the 2D shadows cast by a 3D sculpture are essential for the artistic effect. We introduce computational tools for the creation of shadow art and propose a design process where the user can directly specify the desired shadows by providing a set of binary images and corresponding projection information. Since multiple shadow images often contradict each other, we present a geometric optimization that computes a 3D shadow volume whose shadows best approximate the provided input images. Our analysis shows that this optimization is essential for obtaining physically realizable 3D sculptures. The resulting shadow volume can then be modified with a set of interactive editing tools that automatically respect the often intricate shadow constraints. We demonstrate the potential of our system with a number of complex 3D shadow art sculptures that go beyond what is seen in contemporary art pieces. © 2009 ACM.

  13. Neptune shadows

    Science.gov (United States)

    1999-01-01

    This image of Neptune shows the discovery of shadows in Neptune's atmosphere, shadows cast onto a deep cloud band by small elevated clouds. They are the first cloud shadows ever seen by Voyager on any planet. Estimates of the height of these discrete clouds above the underlying cloud bank can be obtained by careful analysis of this data. The Voyager Mission is conducted by JPL for NASA'S Office of Space Science and Applications.

  14. Shadow Soldiering

    DEFF Research Database (Denmark)

    Mynster Christensen, Maya

    The thesis is an inquiry into what is at stake for a surplus population of militia soldiers in the aftermaths of the civil war in Sierra Leone. The analysis takes its point of departure in how militarised networks are transformed and gradualy morph into new constellations of soldiering. The central...... question the thesis pursues is how the processes of mobilisation connecting these constellations are facilitated, and how the constellations are constituted in the intersection between local and global formations. Shadow soldiering, it is argued, is not a phenomenon existing in parallel with...

  15. The power of shadows - Shadow stereopsis

    Science.gov (United States)

    Puerta, Antonio Medina

    1989-01-01

    It is demonstrated that retinal images with no parallax disparity but with different shadows are fused stereoscopically, imparting depth perception to the imaged scene. Shadows are shown to be an important, hitherto undescribed, stereoscopic cue for depth perception.

  16. Real-time shadows

    CERN Document Server

    Eisemann, Elmar; Assarsson, Ulf; Wimmer, Michael

    2011-01-01

    Important elements of games, movies, and other computer-generated content, shadows are crucial for enhancing realism and providing important visual cues. In recent years, there have been notable improvements in visual quality and speed, making high-quality realistic real-time shadows a reachable goal. Real-Time Shadows is a comprehensive guide to the theory and practice of real-time shadow techniques. It covers a large variety of different effects, including hard, soft, volumetric, and semi-transparent shadows.The book explains the basics as well as many advanced aspects related to the domain

  17. Shadow algorithms data miner

    CERN Document Server

    Woo, Andrew

    2012-01-01

    Digital shadow generation continues to be an important aspect of visualization and visual effects in film, games, simulations, and scientific applications. This resource offers a thorough picture of the motivations, complexities, and categorized algorithms available to generate digital shadows. From general fundamentals to specific applications, it addresses shadow algorithms and how to manage huge data sets from a shadow perspective. The book also examines the use of shadow algorithms in industrial applications, in terms of what algorithms are used and what software is applicable.

  18. Shadowing and hyperbolicity

    CERN Document Server

    Pilyugin, Sergei Yu

    2017-01-01

    Focusing on the theory of shadowing of approximate trajectories (pseudotrajectories) of dynamical systems, this book surveys recent progress in establishing relations between shadowing and such basic notions from the classical theory of structural stability as hyperbolicity and transversality. Special attention is given to the study of "quantitative" shadowing properties, such as Lipschitz shadowing (it is shown that this property is equivalent to structural stability both for diffeomorphisms and smooth flows), and to the passage to robust shadowing (which is also equivalent to structural stability in the case of diffeomorphisms, while the situation becomes more complicated in the case of flows). Relations between the shadowing property of diffeomorphisms on their chain transitive sets and the hyperbolicity of such sets are also described. The book will allow young researchers in the field of dynamical systems to gain a better understanding of new ideas in the global qualitative theory. It will also be of int...

  19. Shadows of Kerr black holes with scalar hair

    CERN Document Server

    Cunha, Pedro V P; Radu, Eugen; Runarsson, Helgi F

    2015-01-01

    Using backwards ray tracing, we study the shadows of Kerr black holes with scalar hair (KBHsSH). KBHsSH interpolate continuously between Kerr BHs and boson stars (BSs), so we start by investigating the lensing of light due to BSs. Moving from the weak to the strong gravity region, BSs - which by themselves have no shadows - are classified, according to the lensing produced, as: $(i)$ non-compact, which yield no multiple images; $(ii)$ compact, which produce an increasing number of Einstein rings and multiple images of the whole celestial sphere; $(iii)$ ultra-compact, which possess light rings, yielding an infinite number of images with (we conjecture) a self-similar structure. The shadows of KBHsSH, for Kerr-like horizons and non-compact BS-like hair, are analogous to, but distinguishable from, those of comparable Kerr BHs. But for non-Kerr-like horizons and ultra-compact BS-like hair, the shadows of KBHsSH are drastically different: novel shapes arise, sizes are considerably smaller and multiple shadows of ...

  20. Shadows behind the computers

    CERN Multimedia

    CERN audiovisual service; Jacques Fichet

    2007-01-01

    EGEE organized a shadowing day to spur female students to take up careers in the IT field. Eleven female staff from CERN’s IT Department were kept under close surveillance last week, shadowed by female students from the Collège du Léman International School as part of the Enabling Grids for E-sciencE project Gender Action Plan.

  1. Radiation shield

    Energy Technology Data Exchange (ETDEWEB)

    Nemezawa, Isao; Kimura, Tadahiro [Hitachi Ltd., Tokyo (Japan); Omori, Tetsu; Mizuochi, Akira

    1997-11-18

    A radiation shield is constituted by using a flexible bag made of a synthetic resin, a rubber plate or a composite member of them. Water is charged therein as a shielding liquid. Water injection ports are formed at the lower surface, and gas exhaustion ports are formed on the upper surface of the radiation shield. A plurality of vertical ribs made of the same material as the bag of the radiation shield are formed, integral with the bag, each at a space on the outer surface of the radiation shield. A reinforcing tube are inserted to the vertical ribs integral with the bag. The reinforcing tube may be made of an metal or non-metal material, but material having a bending strength greater than that of the bag is used. When wide surfaces are constituted in the horizontal direction as radiation shielding surfaces, a plurality of the radiation shields are used being in adjacent in the horizontal direction. The reinforcing tubes in adjacent with each other among the adjacent radiation shields are connected by connectors. (I.N.)

  2. Add-On Shielding for Unshielded Wire

    Science.gov (United States)

    Koenig, J. C.; Billitti, J. W.; Tallon, J. M.

    1983-01-01

    Fabrication sequence used to produce compact shields slipped into place from free ends of wires already soldered into connectors at other ends. Single shields are formed into harnesses by connecting grounding jumpers. Technique is especially useful for small diameter wire attached to microminiature connectors.

  3. Shielding Effectiveness of Laminated Shields

    Directory of Open Access Journals (Sweden)

    B. P. Rao

    2008-12-01

    Full Text Available Shielding prevents coupling of undesired radiated electromagnetic energy into equipment otherwise susceptible to it. In view of this, some studies on shielding effectiveness of laminated shields with conductors and conductive polymers using plane-wave theory are carried out in this paper. The plane wave shielding effectiveness of new combination of these materials is evaluated as a function of frequency and thickness of material. Conductivity of the polymers, measured in previous investigations by the cavity perturbation technique, is used to compute the overall reflection and transmission coefficients of single and multiple layers of the polymers. With recent advances in synthesizing stable highly conductive polymers these lightweight mechanically strong materials appear to be viable alternatives to metals for EM1 shielding.

  4. Shadow of sound

    OpenAIRE

    Prvacki, Ana

    2017-01-01

    Tiré du site Internet de Onestar Press: "Shadow of sound is a musical flip book, an attempt to move sound through pages and to measure music visually. Prvacki demonstrates that 40 seconds of Bach's Minuet in G Major fit on 150 pages.".

  5. Shadows behind the computers

    CERN Multimedia

    2007-01-01

    EGEE organized a shadowing day to spur female students to take up careers in the IT field. Eleven female staff from CERN’s IT Department were kept under close surveillance last week, shadowed by female students from the Collège du Léman International School as part of the Enabling Grids for E-sciencE project Gender Action Plan. The shadowing day was aimed at inspiring young women to think of careers in information technology, by passing on the message that careers in science are open to both men and women and can be rewarding and fun. The students were given a tour of the ATLAS physics experiment and the CERN Computer Centre, as well as the opportunity for one-to-one interaction with CERN IT staff. Traditionally, fewer women work in the IT sector; women currently represent 21% of EGEE staff. The shadowing day was held as part of the EGEE Gender Action Plan, reflecting a commitment to reducing this gender gap. Other initiatives in...

  6. Shadows of Kerr Black Holes with Scalar Hair.

    Science.gov (United States)

    Cunha, Pedro V P; Herdeiro, Carlos A R; Radu, Eugen; Rúnarsson, Helgi F

    2015-11-20

    Using backwards ray tracing, we study the shadows of Kerr black holes with scalar hair (KBHSH). KBHSH interpolate continuously between Kerr BHs and boson stars (BSs), so we start by investigating the lensing of light due to BSs. Moving from the weak to the strong gravity region, BSs-which by themselves have no shadows-are classified, according to the lensing produced, as (i) noncompact, which yield not multiple images, (ii) compact, which produce an increasing number of Einstein rings and multiple images of the whole celestial sphere, and (iii) ultracompact, which possess light rings, yielding an infinite number of images with (we conjecture) a self-similar structure. The shadows of KBHSH, for Kerr-like horizons and noncompact BS-like hair, are analogous to, but distinguishable from, those of comparable Kerr BHs. But for non-Kerr-like horizons and ultracompact BS-like hair, the shadows of KBHSH are drastically different: novel shapes arise, sizes are considerably smaller, and multiple shadows of a single BH become possible. Thus, KBHSH provide quantitatively and qualitatively new templates for ongoing (and future) very large baseline interferometry observations of BH shadows, such as those of the Event Horizon Telescope.

  7. What Colour Is a Shadow?

    Science.gov (United States)

    Hughes, S. W.

    2009-01-01

    What colour is a shadow? Black, grey, or some other colour? This article describes how to use a digital camera to test the hypothesis that a shadow under a clear blue sky has a blue tint. A white sheet of A4 paper was photographed in full sunlight and in shadow under a clear blue sky. The images were analysed using a shareware program called…

  8. Gonad Shielding for Patients Undergoing Conventional Radiological Examinations: Is There Cause for Concern?

    Directory of Open Access Journals (Sweden)

    Karami

    2016-04-01

    Full Text Available Background Gonad shielding is one of the fundamental methods by which to protect reproductive organs in patients undergoing conventional radiological examinations. A lack of or inadequate shielding of the gonads may increase the exposure of these organs and result in malignancies future generations. Objectives The aim of this study is to investigate the prevalence of gonad shielding in patients undergoing conventional radiological examinations and the availability of gonad shields and gonad shielding protocols in radiology departments. Materials and Methods A retrospective, observational cross-sectional study on the application of gonad shielding, the availability of gonad shields and the existence of gonad shielding protocols in radiology departments was performed in five different hospitals in Ahvaz, Iran. Results The highest application of gonad shielding was 6.6% for the pediatric hospital. The prevalence of gonad shielding was less than 0.2%. In 64.3% of the radiography rooms, at least one flat-contact gonad shield of a large size was available. Only large-sized gonad shields were available. Curved-contact and shadow gonad shields did not exist. Gonad shielding protocols were not existence in any of the fourteen radiography rooms investigated. Conclusions Comprehensive protection programs with on-the-job training courses for staff members are strongly recommended, as well as, the provision of radiological shields and gonad shielding protocols in radiology departments to reduce the patient’s radiation dose during radiological examinations.

  9. Is shadow banking really banking?

    OpenAIRE

    Bryan J. Noeth; Rajdeep Sengupta

    2011-01-01

    To those who don't know, the term "shadow banking" probably has a negative connotation. This primer draws parallels between what has been termed the shadow banking sector and the traditional banking sector—showing that they are similar in many ways.

  10. Radiation shielding member

    Energy Technology Data Exchange (ETDEWEB)

    Kasai, Tsutomu

    1998-03-17

    An iron box having optional width, depth and height with no back board is secured to the outer surface of an iron shielding member formed by laminating optional number of iron plates having an optional thickness. Optional number of structural walls acting also as partition walls and comprising a synthetic resin and having a neutron shielding function of a predetermined thickness is disposed between the front plate and the back face of the iron box. Pellets made of a synthetic resin having a radiation shielding function are filled in the iron box. As the synthetic resin having a neutron ray shielding function, a polyethylene resin is preferably used. The radiation shielding member thus constituted is used for a radiation shielding door. Radiation rays irradiated from a chamber are shielded except for neutron rays by the iron shielding member. Neutron rays permeate the iron shielding member, and are shielded by the layers of polyethylene pellets filled in the iron box. (I.N.)

  11. How to See Shadows in 3D

    Science.gov (United States)

    Parikesit, Gea O. F.

    2014-01-01

    Shadows can be found easily everywhere around us, so that we rarely find it interesting to reflect on how they work. In order to raise curiosity among students on the optics of shadows, we can display the shadows in 3D, particularly using a stereoscopic set-up. In this paper we describe the optics of stereoscopic shadows using simple schematic…

  12. Out of shadow / Peeter Linnap

    Index Scriptorium Estoniae

    Linnap, Peeter, 1960-

    2007-01-01

    "Out of shadow" oli näitus Baltimaade 1990. aastate kunstist Ameerika publikule - sõnumiks iseseisvumisjärgsete aastate materiaalse, sotsiaalse ning vaimuelu peegeldused/tõlgendused visuaalses kunstis

  13. NEUTRONIC REACTOR SHIELD

    Science.gov (United States)

    Fermi, E.; Zinn, W.H.

    1957-09-24

    The reactor radiation shield material is comprised of alternate layers of iron-containing material and compressed cellulosic material, such as masonite. The shielding material may be prefabricated in the form of blocks, which can be stacked together in ary desired fashion to form an effective shield.

  14. SHADOW: a new welding technique

    Science.gov (United States)

    Kramer, Thorsten; Olowinsky, Alexander M.; Durand, Friedrich

    2002-06-01

    The new welding technique 'SHADOW ' is introduced. SHADOW means the use of a single pulse to generate a quasi continuous weld of several millimeters in length. HET processing time is defined by the pulse duration of the pulsed laser. At present, a state-of-the-art laser is capable of a maximum pulse duration of 20 ms. The variation of the laser power depend on time is a vital capability of the pulsed laser to adapt the energy deposition into the workpiece. Laser beam welds of several watch components were successfully performed. Similar metals like crowns and axes made out of stainless steel have been welded using pulsed laser radiation. Applying a series of about 130 single pulses for the crown-axis combination the total energy accumulates to 19.5 J. The use of the SHADOW welding technique reduces the energy to 2.5 J. While welding dissimilar metals like stainless steel and bras, the SHADOW welding reduces drastically the contamination as well as the distortion. Laser beam welding of copper has a low process reliability due to the high reflection and the high thermal conductivity. SHADOW welds of 3.6 mm length were performed on 250 micrometers thick copper plates with very high reproducibility. As a result, a pilot plant for laser beam welding of copper plates has been set up. The work to be presented has partly been funded by the European Commission in a project under the contract BRPR-CT-0634.

  15. The Active Muon Shield

    CERN Document Server

    Bezshyiko, Iaroslava

    2016-01-01

    In the SHiP beam-dump of the order of 1011 muons will be produced per second. An active muon-shield is used to magnetically deflect these muons out of the acceptance of the spectrom- eter. This note describes how this shield is modelled and optimized. The SHiP spectrometer is being re-optimized using a conical decay-vessel, and utilizing the possibility to magnetize part of the beam-dump shielding iron. A shield adapted to these new conditions is presented which is significantly shorter and lighter than the shield used in the Technical Proposal (TP), while showing a similar performance.

  16. Resolution Of A Shadow Image

    Science.gov (United States)

    Edgerton, Harold E.

    1982-02-01

    The 19th century art of shadow imaging, as started by Wedgwood (1803), and as used by William Henry Fox-Talbot (1851) in England, has been revived by using a small-area electronic flash lamp and fine grain film. One immediate application has been the photographic recording of large samples of living plankton. The purpose of this paper is to re-examine the resolution of the shadow system, and to describe some of the strobe light sources that are presently available. Also, a modified method of shadow photography is described where enhanced color images give interesting and, perhaps, important color effects that may be useful in the study of plankton and other semitrans-parent subjects.

  17. A Look at Children's Conception of Shadows.

    Science.gov (United States)

    Sia, Archibald Peterson C.

    1980-01-01

    Describes a study designed to compare the gradual development of children's understanding of shadows with Piaget's stages, categorize pupil responses in the shadow tasks, identify typical pupil responses in each category, and enumerate curriculum implications from the investigation. (GS)

  18. Editing soft shadows in a digital photograph.

    Science.gov (United States)

    Mohan, Ankit; Tumblin, Jack; Choudhury, Prasun

    2007-01-01

    This technique for modeling, editing, and rendering shadow edges in a photograph or a synthetic image lets users separate the shadow from the rest of the image and make arbitrary adjustments to its position, sharpness, and intensity.

  19. Detection and Removal of Chromatic Moving Shadows in Surveillance Scenarios

    DEFF Research Database (Denmark)

    Casado, Ivan Huerta; Holte, Michael Boelstoft; Moeslund, Thomas B.

    2009-01-01

      Segmentation in the surveillance domain has to deal with shadows to avoid distortions when detecting moving objects. Most segmentation approaches dealing with shadow detection are typically restricted to penumbra shadows. Therefore, such techniques cannot cope well with umbra shadows. Consequen......  Segmentation in the surveillance domain has to deal with shadows to avoid distortions when detecting moving objects. Most segmentation approaches dealing with shadow detection are typically restricted to penumbra shadows. Therefore, such techniques cannot cope well with umbra shadows...

  20. Study on Processing Method of Image Shadow

    Directory of Open Access Journals (Sweden)

    Wang Bo

    2014-07-01

    Full Text Available In order to effectively remove disturbance of shadow and enhance robustness of information processing of computer visual image, this paper makes study on inspection and removal of image shadow. It makes study the continual removal algorithm of shadow based on integration, the illumination surface and texture, it respectively introduces their work principles and realization method, it can effectively carrying processing for shadow by test.

  1. 47 CFR 80.769 - Shadow loss.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Shadow loss. 80.769 Section 80.769... MARITIME SERVICES Standards for Computing Public Coast Station VHF Coverage § 80.769 Shadow loss. Where the transmission path is obstructed the received signal must be adjusted to include shadow loss. Attenuation due to...

  2. Compact Multiantenna

    Directory of Open Access Journals (Sweden)

    L. Rudant

    2012-01-01

    Full Text Available Planar inverted-f antenna (PIFA and notch antenna are combined within a compact 2-port MIMO antenna. Electrical and magnetic duality of the two antennas avoids a critical coupling and best performances can be expected for multiple-input multiple-output (MIMO communication. When excitation of notch antenna is optimized properly, the notch length can be short enough so that the two antennas can be colocated in a single compact volume. This compact multiantenna design is suitable for integration in MIMO handheld terminals. A prototype for broadband network application in 3.4–3.8’GHz frequency band has been characterized in anechoic chamber.

  3. Influence of a plasma on the shadow of a spherically symmetric black hole

    Science.gov (United States)

    Perlick, Volker; Tsupko, Oleg Yu.; Bisnovatyi-Kogan, Gennady S.

    2015-11-01

    We analytically calculate the influence of a plasma on the shadow of a black hole (or of another compact object). We restrict to spherically symmetric and static situations, where the shadow is circular. The plasma is assumed to be nonmagnetized and pressureless. We derive the general formulas for a spherically symmetric plasma density on an unspecified spherically symmetric and static spacetime. Our main result is an analytical formula for the angular size of the shadow. As a plasma is a dispersive medium, the radius of the shadow depends on the photon frequency. The effect of the plasma is significant only in the radio regime. The formalism applies not only to black holes but also, e.g., to wormholes. As examples for the underlying spacetime model, we consider the Schwarzschild spacetime and the Ellis wormhole. In particular, we treat the case that the plasma is in radial free fall from infinity onto a Schwarzschild black hole. We find that for an observer far away from a Schwarzschild black hole, the plasma has a decreasing effect on the size of the shadow. The perspectives of actually observing the influence of a plasma on the shadows of supermassive black holes are discussed.

  4. TFCX shielding optimization

    Energy Technology Data Exchange (ETDEWEB)

    Yang, S.; Gohar, Y.

    1985-01-01

    Design analyses and tradeoff studies for the bulk shield of the Tokamak Fusion Core Experiment (TFCX) were performed. Several shielding options were considered to lower the capital cost of the shielding system. Optimization analyses were carried out to reduce the nuclear responses in the TF coils and the dose equivalent in the reactor hall one day after shutdown. Two TFCX designs with different toroidal field (TF) coil configurations were considered during this work. The materials for the shield were selected based upon tradeoff studies and the results from the previous design studies. The main shielding materials are water, concrete, and steel balls (Fe1422 or Nitronic 33). Small amounts of boron carbide and lead are employed to reduce activation, nuclear heating in the TF coils, and dose equivalent after shutdown.

  5. Signatures of a shadow biosphere.

    Science.gov (United States)

    Davies, Paul C W; Benner, Steven A; Cleland, Carol E; Lineweaver, Charles H; McKay, Christopher P; Wolfe-Simon, Felisa

    2009-03-01

    Astrobiologists are aware that extraterrestrial life might differ from known life, and considerable thought has been given to possible signatures associated with weird forms of life on other planets. So far, however, very little attention has been paid to the possibility that our own planet might also host communities of weird life. If life arises readily in Earth-like conditions, as many astrobiologists contend, then it may well have formed many times on Earth itself, which raises the question whether one or more shadow biospheres have existed in the past or still exist today. In this paper, we discuss possible signatures of weird life and outline some simple strategies for seeking evidence of a shadow biosphere.

  6. Labour Migration and Shadow Prices

    OpenAIRE

    Henry J. Bruton

    1980-01-01

    The effect of migration and home remittances .on the shadow prices of labour and foreign exchange is analysed here, taking into consideration changes in their social marginal productivities.It is argued tha r appreciation of currency, due to large capital inflows and not to increased productivity, results in a misallocation of resources, and, therefore, there is an urgent need for a proper analysis to determine the optimal level of emigrants.

  7. Shadows Cast on the Screen?

    DEFF Research Database (Denmark)

    Jensen, Sisse Siggaard

    , human-computer interaction, and philosophy. However, a common thread of many studies appears to be the understanding that the relations of a person with his or her avatar(s) are representational: The avatar is seen as the virtual representation of the real in-front-of-the-screen person, like a shadow......, DC Aspen. Finally, with reference to the semiotic understanding it is suggested that we see avatars as transformative mediators of communication...

  8. Shadow removal using bilateral filtering.

    Science.gov (United States)

    Yang, Qingxiong; Tan, Kar-Han; Ahuja, Narendra

    2012-10-01

    In this paper, we propose a simple but effective shadow removal method using a single input image. We first derive a 2-D intrinsic image from a single RGB camera image based solely on colors, particularly chromaticity. We next present a method to recover a 3-D intrinsic image based on bilateral filtering and the 2-D intrinsic image. The luminance contrast in regions with similar surface reflectance due to geometry and illumination variances is effectively reduced in the derived 3-D intrinsic image, while the contrast in regions with different surface reflectance is preserved. However, the intrinsic image contains incorrect luminance values. To obtain the correct luminance, we decompose the input RGB image and the intrinsic image. Each image is decomposed into a base layer and a detail layer. We obtain a shadow-free image by combining the base layer from the input RGB image and the detail layer from the intrinsic image such that the details of the intrinsic image are transferred to the input RGB image from which the correct luminance values can be obtained. Unlike previous methods, the presented technique is fully automatic and does not require shadow detection.

  9. Shielding high energy accelerators

    CERN Document Server

    Stevenson, Graham Roger

    2001-01-01

    After introducing the subject of shielding high energy accelerators, point source, line-of-sight models, and in particular the Moyer model. are discussed. Their use in the shielding of proton and electron accelerators is demonstrated and their limitations noted. especially in relation to shielding in the forward direction provided by large, flat walls. The limitations of reducing problems to those using it cylindrical geometry description are stressed. Finally the use of different estimators for predicting dose is discussed. It is suggested that dose calculated from track-length estimators will generally give the most satisfactory estimate. (9 refs).

  10. Paired regions for shadow detection and removal.

    Science.gov (United States)

    Guo, Ruiqi; Dai, Qieyun; Hoiem, Derek

    2013-12-01

    In this paper, we address the problem of shadow detection and removal from single images of natural scenes. Differently from traditional methods that explore pixel or edge information, we employ a region-based approach. In addition to considering individual regions separately, we predict relative illumination conditions between segmented regions from their appearances and perform pairwise classification based on such information. Classification results are used to build a graph of segments, and graph-cut is used to solve the labeling of shadow and nonshadow regions. Detection results are later refined by image matting, and the shadow-free image is recovered by relighting each pixel based on our lighting model. We evaluate our method on the shadow detection dataset in Zhu et al. In addition, we created a new dataset with shadow-free ground truth images, which provides a quantitative basis for evaluating shadow removal. We study the effectiveness of features for both unary and pairwise classification.

  11. iSHIELD - A Line Source Application of SHIELD11

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, W.R.; Rokni, S.H.; /SLAC

    2006-04-27

    iSHIELD11 performs a line-source numerical integration of radiation source terms that are defined by the iSHIELD11 computer code[1] . An example is provided to demonstrate how one can use iSHIELD11 to perform a shielding analysis for a 250 GeV electron linear accelerator.

  12. Adhesive particle shielding

    Science.gov (United States)

    Klebanoff, Leonard Elliott [Dublin, CA; Rader, Daniel John [Albuquerque, NM; Walton, Christopher [Berkeley, CA; Folta, James [Livermore, CA

    2009-01-06

    An efficient device for capturing fast moving particles has an adhesive particle shield that includes (i) a mounting panel and (ii) a film that is attached to the mounting panel wherein the outer surface of the film has an adhesive coating disposed thereon to capture particles contacting the outer surface. The shield can be employed to maintain a substantially particle free environment such as in photolithographic systems having critical surfaces, such as wafers, masks, and optics and in the tools used to make these components, that are sensitive to particle contamination. The shield can be portable to be positioned in hard-to-reach areas of a photolithography machine. The adhesive particle shield can incorporate cooling means to attract particles via the thermophoresis effect.

  13. Moving Shadow Detection in Video Using Cepstrum

    Directory of Open Access Journals (Sweden)

    Fuat Cogun

    2013-01-01

    Full Text Available Moving shadows constitute problems in various applications such as image segmentation and object tracking. The main cause of these problems is the misclassification of the shadow pixels as target pixels. Therefore, the use of an accurate and reliable shadow detection method is essential to realize intelligent video processing applications. In this paper, a cepstrum-based method for moving shadow detection is presented. The proposed method is tested on outdoor and indoor video sequences using well-known benchmark test sets. To show the improvements over previous approaches, quantitative metrics are introduced and comparisons based on these metrics are made.

  14. Influence of a plasma on the shadow of a spherically symmetric black hole

    CERN Document Server

    Perlick, Volker; Bisnovatyi-Kogan, Gennady S

    2015-01-01

    We analytically calculate the influence of a plasma on the shadow of a black hole (or of another compact object). We restrict to spherically symmetric and static situations, where the shadow is circular. The plasma is assumed to be non-magnetized and pressure-less. We derive the general formulas for a spherically symmetric plasma density on an unspecified spherically symmetric and static spacetime. The formalism applies not only to black holes but also, e.g., to wormholes. As examples for the underlying spacetime model, we consider the Schwarzschild spacetime and the Ellis wormhole. In particular, we treat the case that the plasma is in radial free fall from infinity onto a Schwarzschild black hole. The perspectives of actually observing the influence of a plasma on the shadows of supermassive black holes are discussed.

  15. Grounding, shielding, and bonding

    Science.gov (United States)

    Catrysse, J.

    1991-06-01

    In the electromagnetic compatibility design (EMC) of systems and circuits, both grounding and shielding are related to the coupling mechanisms of the system with (radiated) electromagnetic fields. Grounding is more related to the source or victim circuit (or system) and determines the characteristic of the coupling mechanism between fields and currents/voltages. Shielding is a way of interacting in the radiation path of an electromagnetic field. The basic principles and practical design rules are discussed.

  16. Radiological Shielding Design for the Neutron High-Resolution Backscattering Spectrometer EMU at the OPAL Reactor

    Science.gov (United States)

    Ersez, Tunay; Esposto, Fernando; Souza, Nicolas R. de

    2017-09-01

    The shielding for the neutron high-resolution backscattering spectrometer (EMU) located at the OPAL reactor (ANSTO) was designed using the Monte Carlo code MCNP 5-1.60. The proposed shielding design has produced compact shielding assemblies, such as the neutron pre-monochromator bunker with sliding cylindrical block shields to accommodate a range of neutron take-off angles, and in the experimental area - shielding of neutron focusing guides, choppers, flight tube, backscattering monochromator, and additional shielding elements inside the Scattering Tank. These shielding assemblies meet safety and engineering requirements and cost constraints. The neutron dose rates around the EMU instrument were reduced to < 0.5 µSv/h and the gamma dose rates to a safe working level of ≤ 3 µSv/h.

  17. Wedge Diffraction as an Instance of Radiative Shielding

    CERN Document Server

    Grzesik, J A

    2016-01-01

    The celebrated Sommerfeld wedge diffraction solution is reexamined from a null interior field perspective. Exact surface currents provided by that solution, when considered as disembodied half-plane laminae radiating into an ambient, uniform space both inside and outside the wedge proper, do succeed in reconstituting both a specular, mirror field above the exposed face, and a shielding plane-wave field of a sign opposite to that of the incoming excitation which, under superposition, creates both the classical, geometric-optics shadow, and a strictly null interior field at the dominant, plane-wave level. Both mirror and shadow radiated fields are controlled by the residue at just one simple pole encountered during a spectral radiative field assembly, fixed in place by incidence direction $\\phi_{0}$ as measured from the exposed face. The radiated fields further provide diffractive contributions drawn from two saddle points that track observation angle $\\phi.$ Even these, more or less asymptotic contributions, a...

  18. Alorithm for Shadow Detection in Real Colour Images

    OpenAIRE

    Sanjeev Kumar,; Anupreet Kaur

    2010-01-01

    Shadow detection in real scene images is always a challenging but yet interesting area. Most shadow detection and segmentation methods are based on image analysis. This paper aimed to give a comprehensive and critical study of current shadow detection methods. Various approaches have been discussed related to shadow detection in images. The principles of these methods rely on intensity difference or texture analysis of the shadow area and the bright area of the same surface. A realtime shadow...

  19. Shadow detection using a physical basis

    NARCIS (Netherlands)

    Withagen, P.J.; Groen, F.C.A.; Schutte, K.

    2008-01-01

    Shadow detection is an important aspect of foreground/ background classification. Many techniques exist, most of them assuming that casting a shadow results only in a change in intensity and no change in color. In this paper we show that in most practical indoor and outdoor situations there will

  20. Detection of Cast Shadows in Surveillance Applications

    DEFF Research Database (Denmark)

    Erbou, Søren G.; Sørensen, Helge Bjarne Dissing; Stage, Bjarne

    2005-01-01

    Cast shadows from moving objects reduce the general ability of robust classification and tracking of these objects, in outdoor surveillance applications. A method for segmentation of cast shadows is proposed, combining statistical features with a new similarity feature, derived from a physics...

  1. Shadow detection using a physical basis

    NARCIS (Netherlands)

    Groen, F.C.A.; Withagen, P.J.; Schutte, K.

    2007-01-01

    Shadow detection is an important aspect of foreground/background classification. Many techniques exist, most of them assuming that only the intensity changes under shadow. In this paper we show that in most practical indoor and outdoor situations there will also be a color shift. We propose an

  2. Shadow-free single-pixel imaging

    Science.gov (United States)

    Li, Shunhua; Zhang, Zibang; Ma, Xiao; Zhong, Jingang

    2017-11-01

    Single-pixel imaging is an innovative imaging scheme and receives increasing attention in recent years, for it is applicable for imaging at non-visible wavelengths and imaging under weak light conditions. However, as in conventional imaging, shadows would likely occur in single-pixel imaging and sometimes bring negative effects in practical uses. In this paper, the principle of shadows occurrence in single-pixel imaging is analyzed, following which a technique for shadows removal is proposed. In the proposed technique, several single-pixel detectors are used to detect the backscattered light at different locations so that the shadows in the reconstructed images corresponding to each detector shadows are complementary. Shadow-free reconstruction can be derived by fusing the shadow-complementary images using maximum selection rule. To deal with the problem of intensity mismatch in image fusion, we put forward a simple calibration. As experimentally demonstrated, the technique is able to reconstruct monochromatic and full-color shadow-free images.

  3. Extensive Reading and the Effect of Shadowing

    Science.gov (United States)

    Nakanishi, Takayuki; Ueda, Atsuko

    2011-01-01

    The aim of this study is to investigate the effects of extensive reading (ER) and shadowing on performance on reading comprehension tests. This study addressed the following research questions: (a) Can extensive reading improve students' reading comprehension? and (b) can shadowing enhance the effects of extensive reading? The participants in the…

  4. Compact vortices

    Energy Technology Data Exchange (ETDEWEB)

    Bazeia, D.; Losano, L.; Marques, M.A.; Zafalan, I. [Universidade Federal da Paraiba, Departamento de Fisica, Joao Pessoa, PB (Brazil); Menezes, R. [Universidade Federal da Paraiba, Departamento de Ciencias Exatas, Rio Tinto, PB (Brazil); Universidade Federal de Campina Grande, Departamento de Fisica, Campina Grande, PB (Brazil)

    2017-02-15

    We study a family of Maxwell-Higgs models, described by the inclusion of a function of the scalar field that represent generalized magnetic permeability. We search for vortex configurations which obey first-order differential equations that solve the equations of motion. We first deal with the asymptotic behavior of the field configurations, and then implement a numerical study of the solutions, the energy density and the magnetic field. We work with the generalized permeability having distinct profiles, giving rise to new models, and we investigate how the vortices behave, compared with the solutions of the corresponding standard models. In particular, we show how to build compact vortices, that is, vortex solutions with the energy density and magnetic field vanishing outside a compact region of the plane. (orig.)

  5. Tricolor attenuation model for shadow detection.

    Science.gov (United States)

    Tian, Jiandong; Sun, Jing; Tang, Yandong

    2009-10-01

    Shadows, the common phenomena in most outdoor scenes, bring many problems in image processing and computer vision. In this paper, we present a novel method focusing on extracting shadows from a single outdoor image. The proposed tricolor attenuation model (TAM) that describe the attenuation relationship between shadow and its nonshadow background is derived based on image formation theory. The parameters of the TAM are fixed by using the spectral power distribution (SPD) of daylight and skylight, which are estimated according to Planck's blackbody irradiance law. Based on the TAM, a multistep shadow detection algorithm is proposed to extract shadows. Compared with previous methods, the algorithm can be applied to process single images gotten in real complex scenes without prior knowledge. The experimental results validate the performance of the model.

  6. ASI/MET shadow & airbags

    Science.gov (United States)

    1997-01-01

    A shadow of the Atmospheric Structure Instrument/Meteorology Package (ASI/MET) has been cast on a rock at right in this image, taken by the Imager for Mars Pathfinder (IMP) on Sol 4. The instrument appears in two different sections due to image parallax. The ASI/MET is an engineering subsytem that acquired atmospheric data during Pathfinder's descent, and will continue to get more data through the entire landed mission. Portions of a lander petal and deflated airbag are visible, in addition to several rocks of varying sizes in the distance.Mars Pathfinder was developed and managed by the Jet Propulsion Laboratory (JPL) for the National Aeronautics and Space Administration. JPL is an operating division of the California Institute of Technology (Caltech). The IMP was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

  7. Electrostatic shielding of transformers

    Energy Technology Data Exchange (ETDEWEB)

    De Leon, Francisco

    2017-11-28

    Toroidal transformers are currently used only in low-voltage applications. There is no published experience for toroidal transformer design at distribution-level voltages. Toroidal transformers are provided with electrostatic shielding to make possible high voltage applications and withstand the impulse test.

  8. Shield For Flexible Pipe

    Science.gov (United States)

    Ponton, Michael K.; Williford, Clifford B.; Lagen, Nicholas T.

    1995-01-01

    Cylindrical shield designed to fit around flexible pipe to protect nearby workers from injury and equipment from damage if pipe ruptures. Designed as pressure-relief device. Absorbs impact of debris ejected radially from broken flexible pipe. Also redirects flow of pressurized fluid escaping from broken pipe onto flow path allowing for relief of pressure while minimizing potential for harm.

  9. Lightweight Shield Against Space Debris

    Science.gov (United States)

    Redmon, John W., Jr.; Lawson, Bobby E.; Miller, Andre E.; Cobb, W. E.

    1992-01-01

    Report presents concept for lightweight, deployable shield protecting orbiting spacecraft against meteoroids and debris, and functions as barrier to conductive and radiative losses of heat. Shield made in four segments providing 360 degree coverage of cylindrical space-station module.

  10. Low-cost telemedicine device performing cell and particle size measurement based on lens-free shadow imaging technology.

    Science.gov (United States)

    Roy, Mohendra; Seo, Dongmin; Oh, Chang-Hyun; Nam, Myung-Hyun; Kim, Young Jun; Seo, Sungkyu

    2015-05-15

    Recent advances in lens-free shadow imaging technology have enabled a new class of cell imaging platform, which is a suitable candidate for point-of-care facilities. In this paper, we firstly demonstrate a compact and low-cost telemedicine device providing automated cell and particle size measurement based on lens-free shadow imaging technology. Using the generated shadow (or diffraction) patterns, the proposed approach can detect and measure the sizes of more than several hundreds of micro-objects simultaneously within a single digital image frame. In practical experiments, we defined four types of shadow parameters extracted from each micro-object shadow pattern, and found that a specific shadow parameter (peak-to-peak distance, PPD) demonstrated a linear relationship with the actual micro-object sizes. By using this information, a new algorithm suitable for operation on both a personal computer (PC) and a cell phone was also developed, providing automated size detection of poly-styrenemicro-beads and biological cells such as red blood cells, MCF-7, HepG2, and HeLa. Results from the proposed device were compared with those of a conventional optical microscope, demonstrating good agreement between two approaches. In contrast to other existing cell and particle size measurement approaches, such as Coulter counter, flow-cytometer, particle-size analyzer, and optical microscope, this device can provide accurate cell and particle size information with a 2 µm maximum resolution, at almost no cost (less than 100 USD), within a compact instrumentation size (9.3×9.0×9.0 cm(3)), and in a rapid manner (within 1 min). The proposed lens-free automated particle and cell size measurement device, based on shadow imaging technology, can be utilized as a powerful tool for many cell and particle handling procedures, including environmental, pharmaceutical, biological, and clinical applications. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Spectral anomaly detection in deep shadows.

    Science.gov (United States)

    Kanaev, Andrey V; Murray-Krezan, Jeremy

    2010-03-20

    Although several hyperspectral anomaly detection algorithms have proven useful when illumination conditions provide for enough light, many of these same detection algorithms fail to perform well when shadows are also present. To date, no general approach to the problem has been demonstrated. In this paper, a novel hyperspectral anomaly detection algorithm that adapts the dimensionality of the spectral detection subspace to multiple illumination levels is described. The novel detection algorithm is applied to reflectance domain hyperspectral data that represents a variety of illumination conditions: well illuminated and poorly illuminated (i.e., shadowed). Detection results obtained for objects located in deep shadows and light-shadow transition areas suggest superiority of the novel algorithm over standard subspace RX detection.

  12. The Shadow Sphere in International Relations

    Directory of Open Access Journals (Sweden)

    A N Mikhailenko

    2012-06-01

    Full Text Available The article deals with the shadow sphere in international relations. Approaches to its classification are proposed, main principles of its functioning and influence on world politics are analyzed.

  13. The little book of light and shadow

    CERN Document Server

    Thornton, Linda

    2013-01-01

    Encourage your Early Learners to becom investigators by exploring the concept of light and shadow. These simple and effective activities can be carried out independently with the focus on natural resources.

  14. Fading and shadowing in wireless systems

    CERN Document Server

    Shankar, P Mohana

    2017-01-01

    This book offers a comprehensive overview of fading and shadowing in wireless channels. A number of statistical models including simple, hybrid, compound and cascaded ones are presented along with a detailed discussion of diversity techniques employed to mitigate the effects of fading and shadowing. The effects of co-channel interference before and after the implementation of diversity are also analyzed. To facilitate easy understanding of the models and the analysis, the background on probability and random variables is presented with relevant derivations of densities of the sums, products, ratios as well as order statistics of random variables. The book also provides material on digital modems of interest in wireless systems. The updated edition expands the background materials on probability by offering sections on Laplace and Mellin transforms, parameter estimation, statistical testing and receiver operating characteristics. Newer models for fading, shadowing and shadowed fading are included along with th...

  15. Compact torus

    Energy Technology Data Exchange (ETDEWEB)

    Furth, H.P.

    1980-10-01

    The objective of the compact torus approach is to provide toroidal magnetic-field configurations that are based primarily on plasma currents and can be freed from closely surrounding mechanical structures. Some familiar examples are the current-carrying plasma rings of reversed-field theta pinches and relativistic-electron smoke ring experiments. The spheromak concept adds an internal toroidal magnetic field component, in order to enhance MHD stability. In recent experiments, three different approaches have been used to generate spheromak plasmas: (1) the reversed-field theta pinch; (2) the coaxial plasma gun; (3) a new quasi-static method, based on the initial formation of a toroidal plasma sleeve around a mechanical ring that generates poloidal and toroidal fluxes, followed by field-line reconnection to form a detached spheromak plasma. The theoretical and experimental MHD stability results for the spheromak configuration are found to have common features.

  16. Evaluation of Digital Shadow Economy Prevention Measures

    Directory of Open Access Journals (Sweden)

    Remeikiene Rita

    2016-06-01

    Full Text Available Although during the past few years the scopes of shadow economy in Lithuania have slightly decreased, different forms of this phenomenon, in particular digital shadow activities, still generate a significant part of the overall value added. As no constant estimations of the scope of digital shadow economy have been made in Lithuania, alleviation of this problem is based on consequence fighting rather than reason elimination. Digital shadow economy poses a significant challenge for law enforcement agencies concerning its investigation and prevention. Hence, it is purposeful to research both theoretical and practical aspects of digital shadow economy prevention in order to identify the measures that could be used for the efficient reduction of the scope of this phenomenon. The aim of this research is to identify the measures of digital shadow economy prevention and compare the attitudes of governmental institutions and consumers towards the efficiency of these measures. The results of the empirical research showed that both consumers and experts agree that the level of tax morale has to be raised not only by using the measures of self-education but also by introducing long-term educational programmes; second, public authorities should ensure business friendly environment, actively implement the principles of justice and officially acknowledge and announce the concept of digital shadow economy; finally, for more efficient detection of the cases of digital shadow activities, it is necessary to reinforce current labour resources that should be specially trained to be able to disclose revenue hiding and tax evasion schemes, employed in e-trade.

  17. Boundary Correct Real-Time Soft Shadows

    DEFF Research Database (Denmark)

    Jacobsen, Bjarke; Christensen, Niels Jørgen; Larsen, Bent Dalgaard

    2004-01-01

    This paper describes a method to determine correct shadow boundaries from an area light source using umbra and penumbra volumes. The light source is approximated by a circular disk as this gives a fast way to extrude the volumes. The method also gives a crude estimate of the visibility of the area...... for implementation on most programmable hardware. Though some crude approximations are used in the visibility function, the method can be used to produce soft shadows with correct boundaries in real time....

  18. Roof Shield for Advance and Retreat Mining

    Science.gov (United States)

    Lewis, E. V.

    1985-01-01

    Shield sections change their configuration to suit mining mode. Articulation cylinders raise rear shield to advance position, and locking cylinders hold it there. To change to retreat position articulation cylinders lower shield. Locking pins at edge of outermost shield plate latch shield to chock base. Shield accommodates roof heights ranging from 36 to 60 inches (0.9 to 1.52 meters).

  19. Light shielding apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Richard Dean; Thom, Robert Anthony

    2017-10-10

    A light shielding apparatus for blocking light from reaching an electronic device, the light shielding apparatus including left and right support assemblies, a cross member, and an opaque shroud. The support assemblies each include primary support structure, a mounting element for removably connecting the apparatus to the electronic device, and a support member depending from the primary support structure for retaining the apparatus in an upright orientation. The cross member couples the left and right support assemblies together and spaces them apart according to the size and shape of the electronic device. The shroud may be removably and adjustably connectable to the left and right support assemblies and configured to take a cylindrical dome shape so as to form a central space covered from above. The opaque shroud prevents light from entering the central space and contacting sensitive elements of the electronic device.

  20. Effect of compositional variation in plutonium on process shielding design

    Energy Technology Data Exchange (ETDEWEB)

    Brown, T.H.

    1997-11-01

    Radiation dose rate from plutonium with high {sup 239}Pu content varies with initial nuclidic content, radioactive decay time, and impurity elemental content. The two idealized states of old plutonium and clean plutonium, whose initial compositions are given, provide approximate upper and lower bounds on dose rate variation. Whole-body dose rates were calculated for the two composition states, using unshielded and shielded plutonium spheres of varying density. The dose rates from these variable density spheres are similar to those from expanded plutonium configurations encountered during processing. The dose location of 40 cm from the sphere center is representative of operator standoff for direct handling of plutonium inside a glove box. The results have shielding implications for glove boxes with only structurally inherent shielding, especially for processing of old plutonium in an expanded configuration. Further reduction in total dose rate by using lead to reduce photon dose rate is shown for two density cases representing compact and expanded plutonium configurations.

  1. A contribution to shielding effectiveness analysis of shielded tents

    Directory of Open Access Journals (Sweden)

    Vranić Zoran M.

    2004-01-01

    Full Text Available An analysis of shielding effectiveness (SE of the shielded tents made of the metallised fabrics is given. First, two electromagnetic characteristic fundamental for coupling through electrically thin shield, the skin depth break frequency and the surface resistance or transfer impedance, is defined and analyzed. Then, the transfer function and the SE are analyzed regarding to the frequency range of interest to the Electromagnetic Compatibility (EMC Community.

  2. Measurement of the transient shielding effectiveness of shielding cabinets

    Directory of Open Access Journals (Sweden)

    H. Herlemann

    2008-05-01

    Full Text Available Recently, new definitions of shielding effectiveness (SE for high-frequency and transient electromagnetic fields were introduced by Klinkenbusch (2005. Analytical results were shown for closed as well as for non closed cylindrical shields. In the present work, the shielding performance of different shielding cabinets is investigated by means of numerical simulations and measurements inside a fully anechoic chamber and a GTEM-cell. For the GTEM-cell-measurements, a downscaled model of the shielding cabinet is used. For the simulations, the numerical tools CONCEPT II and COMSOL MULTIPHYSICS were available. The numerical results agree well with the measurements. They can be used to interpret the behaviour of the shielding effectiveness of enclosures as function of frequency. From the measurement of the electric and magnetic fields with and without the enclosure in place, the electric and magnetic shielding effectiveness as well as the transient shielding effectiveness of the enclosure are calculated. The transient SE of four different shielding cabinets is determined and discussed.

  3. Improving Students’ Listening Skill Through Shadowing

    Directory of Open Access Journals (Sweden)

    Mukminatus Zuhriyah

    2016-12-01

    Full Text Available Listening is the first part of language skills that everyone gets when learning a language. It comes before speaking, reading, and writing. Meanwhile, most of the students get difficulty to learn listening of a foreign language, especially English. That is why shadowing was applied in the listening class as one of the solutions to make the learners of English listening easy to understand what the speaker says. This collaborative classroom action research was generally to know whether or not shadowing could improve the students listening skill. It was also specifically to know: (1 the lecturer’s activities, (2 the students’ activities, and (3 the students’ responses during the implementation of shadowing in the listening class. The subjects were 18 students of the third semester of English department of education faculty of Hasyim Asy’ari university (UNHASY Tebuireng Jombang in the academic year of 2016/2017. The data were obtained from the observations got from the notes written by the collaborator and the listening test. The students’ listening skill improved after the implementation of shadowing. It could be seen in the improvement of mean score, from 74.2 in cycle one to 75 in cycle two. Then, the precentage of students passing the minimum mastery criteria also improved, from 61% in cycle one to 77.8% in cycle two. Thus, it can be concluded that shadowing could improve students’ listening skill.

  4. What shadows reveal about object structure.

    Science.gov (United States)

    Kriegman, D J; Belhumeur, P N

    2001-08-01

    In a scene observed from a fixed viewpoint, the set of shadow boundaries in an image changes as a point light source (nearby or at infinity) assumes different locations. We show that for any finite set of point light sources illuminating an object viewed under either orthographic or perspective projection, there is an equivalence class of object shapes having the same set of shadows. Members of this equivalence class differ by a four-parameter family of projective transformations, and the shadows of a transformed object are identical when the same transformation is applied to the light source locations. Under orthographic projection, this family is the generalized bas-relief (GBR) transformation, and we show that the GBR transformation is the only family of transformations of an object's shape for which the complete set of imaged shadows is identical. Finally, we show that given multiple images under differing and unknown light source directions, it is possible to reconstruct both an object's surface and the light source locations up to this family of transformations from the shadows alone.

  5. An Improved Fuzzy c-Means Clustering Algorithm Based on Shadowed Sets and PSO

    Directory of Open Access Journals (Sweden)

    Jian Zhang

    2014-01-01

    Full Text Available To organize the wide variety of data sets automatically and acquire accurate classification, this paper presents a modified fuzzy c-means algorithm (SP-FCM based on particle swarm optimization (PSO and shadowed sets to perform feature clustering. SP-FCM introduces the global search property of PSO to deal with the problem of premature convergence of conventional fuzzy clustering, utilizes vagueness balance property of shadowed sets to handle overlapping among clusters, and models uncertainty in class boundaries. This new method uses Xie-Beni index as cluster validity and automatically finds the optimal cluster number within a specific range with cluster partitions that provide compact and well-separated clusters. Experiments show that the proposed approach significantly improves the clustering effect.

  6. SHIELDS Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Jordanova, Vania Koleva [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-10-03

    Predicting variations in the near-Earth space environment that can lead to spacecraft damage and failure, i.e. “space weather”, remains a big space physics challenge. A new capability was developed at Los Alamos National Laboratory (LANL) to understand, model, and predict Space Hazards Induced near Earth by Large Dynamic Storms, the SHIELDS framework. This framework simulates the dynamics of the Surface Charging Environment (SCE), the hot (keV) electrons representing the source and seed populations for the radiation belts, on both macro- and micro-scale. In addition to using physics-based models (like RAM-SCB, BATS-R-US, and iPIC3D), new data assimilation techniques employing data from LANL instruments on the Van Allen Probes and geosynchronous satellites were developed. An order of magnitude improvement in the accuracy in the simulation of the spacecraft surface charging environment was thus obtained. SHIELDS also includes a post-processing tool designed to calculate the surface charging for specific spacecraft geometry using the Curvilinear Particle-In-Cell (CPIC) code and to evaluate anomalies' relation to SCE dynamics. Such diagnostics is critically important when performing forensic analyses of space-system failures.

  7. Hypervelocity impact shield

    Science.gov (United States)

    Cour-Palais, Burton G. (Inventor); Crews, Jeanne Lee (Inventor)

    1991-01-01

    A hypervelocity impact shield and method for protecting a wall structure, such as a spacecraft wall, from impact with particles of debris having densities of about 2.7 g/cu cm and impact velocities up to 16 km/s are disclosed. The shield comprises a stack of ultra thin sheets of impactor disrupting material supported and arranged by support means in spaced relationship to one another and mounted to cover the wall in a position for intercepting the particles. The sheets are of a number and spacing such that the impacting particle and the resulting particulates of the impacting particle and sheet material are successively impact-shocked to a thermal state of total melt and/or vaporization to a degree as precludes perforation of the wall. The ratio of individual sheet thickness to the theoretical diameter of particles of debris which may be of spherical form is in the range of 0.03 to 0.05. The spacing between adjacent sheets is such that the debris cloud plume of liquid and vapor resulting from an impacting particle penetrating a sheet does not puncture the next adjacent sheet prior to the arrival thereat of fragment particulates of sheet material and the debris particle produced by a previous impact.

  8. New Toroid shielding design

    CERN Multimedia

    Hedberg V

    On the 15th of June 2001 the EB approved a new conceptual design for the toroid shield. In the old design, shown in the left part of the figure above, the moderator part of the shielding (JTV) was situated both in the warm and cold areas of the forward toroid. It consisted both of rings of polyethylene and hundreds of blocks of polyethylene (or an epoxy resin) inside the toroid vacuum vessel. In the new design, shown to the right in the figure above, only the rings remain inside the toroid. To compensate for the loss of moderator in the toroid, the copper plug (JTT) has been reduced in radius so that a layer of borated polyethylene can be placed around it (see figure below). The new design gives significant cost-savings and is easier to produce in the tight time schedule of the forward toroid. Since the amount of copper is reduced the weight that has to be carried by the toroid is also reduced. Outgassing into the toroid vacuum was a potential problem in the old design and this is now avoided. The main ...

  9. Comparison among Models to Estimate the Shielding Effectiveness Applied to Conductive Textiles

    Directory of Open Access Journals (Sweden)

    Alberto Lopez

    2013-01-01

    Full Text Available The purpose of this paper is to present a comparison among two models and its measurement to calculate the shielding effectiveness of electromagnetic barriers, applying it to conductive textiles. Each one, models a conductive textile as either a (1 wire mesh screen or (2 compact material. Therefore, the objective is to perform an analysis of the models in order to determine which one is a better approximation for electromagnetic shielding fabrics. In order to provide results for the comparison, the shielding effectiveness of the sample has been measured by means of the standard ASTM D4935-99.

  10. The Hero and His Shadow

    Directory of Open Access Journals (Sweden)

    Simona Micali

    2010-08-01

    Full Text Available

     

    Abstract (E: This essay traces the literary theme of the ‘disobedient shadow’ from the Romantic archetype to its adaptation nineteenth- and twentieth-century fantastic fiction. Focusing on texts in which the shadow takes up its own identity, becoming an uncanny double of its master, it is argued that the development of this theme is closely linked with the evolution of the human subject through the epistemological and cultural revolutions of the last two centuries.

    Abstract (F:

     

    Cet article retrace l’évolution du thème littéraire de l’ « ombre désobéissante », de l’archétype romantique aux mutations ultérieures dans la fiction fantastique des 19e et 20e siècles. Il examine un corpus où l’ombre assume son indépendance, devenant un double de son maître dans un esprit que l’on sait être maintenant celui de l

  11. Moving Shadow Detection in Video Using Cepstrum Regular Paper

    OpenAIRE

    Cogun, Fuat; Cetin, Ahmet Enis

    2013-01-01

    Moving shadows constitute problems in various applications such as image segmentation and object tracking. The main cause of these problems is the misclassification of the shadow pixels as target pixels. Therefore, the use of an accurate and reliable shadow detection method is essential to realize intelligent video processing applications. In this paper, a cepstrum‐based method for moving shadow detection is presented. The proposed method is tested on outdoor and indoor video sequences using ...

  12. Infants' perception of lightness changes related to cast shadows.

    Directory of Open Access Journals (Sweden)

    Kazuki Sato

    Full Text Available When humans perceive the lightness of an object's surface in shadows there is an implicit assumption that cast shadows dim the surface. In two experiments, we investigated whether 5- to 8-month-old infants make this assumption about shadows. According to this shadow assumption, the apparent change in lightness produced by shadows on an object's surface are attributed to blocked light sources. If infants can use the shadow assumption to perceive the object's lightness in shadows, they will also be able to detect unnatural lightness changes in shadows. We compared the infants' looking times to the unnatural and the natural lightness changes in the shadow when an object (duck goes through the cast shadow. In Experiment 1, we examined whether infants could detect the unnatural lightness changes of the object's surface in shadows. We created computer-graphic movies of unnatural and natural lightness changes to the duck's surface. Our results showed that 7- to 8-month-olds but not 5- to 6-month-olds significantly preferred the movie with the unnatural changes in lightness, indicating that only the older infants could detect these changes. In Experiment 2, we confirmed that the infants' preference was based on the detection of unnatural lightness changes according to the shadow assumption. The natural and the unnatural lightness changes of Experiment 1 were presented without cast shadows. Under these conditions, neither younger nor older infants showed a significant preference. Taken together, the experiments showed that 7- to 8-month-old infants could detect the unnaturalness of a surface's lightness changes produced by shadows. In conclusion, our findings suggest that 7- to 8-month-old infants can perceive an object's lightness in shadows by using an assumption that cast shadows dim the surface of an object.

  13. Radiation Shielding for Fusion Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Santoro, R.T.

    1999-10-01

    Radiation shielding requirements for fusion reactors present different problems than those for fission reactors and accelerators. Fusion devices, particularly tokamak reactors, are complicated by geometry constraints that complicate disposition of fully effective shielding. This paper reviews some of these shielding issues and suggested solutions for optimizing the machine and biological shielding. Radiation transport calculations are essential for predicting and confirming the nuclear performance of the reactor and, as such, must be an essential part of the reactor design process. Development and optimization of reactor components from the first wall and primary shielding to the penetrations and containment shielding must be carried out in a sensible progression. Initial results from one-dimensional transport calculations are used for scoping studies and are followed by detailed two- and three-dimensional analyses to effectively characterize the overall radiation environment. These detail model calculations are essential for accounting for the radiation leakage through ports and other penetrations in the bulk shield. Careful analysis of component activation and radiation damage is cardinal for defining remote handling requirements, in-situ replacement of components, and personnel access at specific locations inside the reactor containment vessel. Radiation shielding requirements for fusion reactors present different problems than those for fission reactors and accelerators. Fusion devices, particularly tokamak reactors, are complicated by geometry constraints that complicate disposition of fully effective shielding. This paper reviews some of these shielding issues and suggested solutions for optimizing the machine and biological shielding. Radiation transport calculations are essential for predicting and confirming the nuclear performance of the reactor and, as such, must be an essential part of the reactor design process. Development and optimization of reactor

  14. Socket Shield Technique

    OpenAIRE

    Ferreira, João Eduardo Freitas

    2017-01-01

    Nos dias atuais, é cada vez mais comum a realização de extrações de dentes que estejam severamente comprometidos e substituí-los por implantes dentários. Após extração, existe uma reabsorção de osso alveolar que vai resultar numa perda de osso vertical e horizontal, tornando-se um dos fatores que subsequentemente se vai colocar como uma das maiores dificuldades na colocação de implantes. A técnica Socket Shield é uma técnica de preservação de osso alveolar em situações de implantes imediatos,...

  15. Welding shield for coupling heaters

    Science.gov (United States)

    Menotti, James Louis

    2010-03-09

    Systems for coupling end portions of two elongated heater portions and methods of using such systems to treat a subsurface formation are described herein. A system may include a holding system configured to hold end portions of the two elongated heater portions so that the end portions are abutted together or located near each other; a shield for enclosing the end portions, and one or more inert gas inlets configured to provide at least one inert gas to flush the system with inert gas during welding of the end portions. The shield may be configured to inhibit oxidation during welding that joins the end portions together. The shield may include a hinged door that, when closed, is configured to at least partially isolate the interior of the shield from the atmosphere. The hinged door, when open, is configured to allow access to the interior of the shield.

  16. Chromatic Shadow Detection and Tracking for Moving Foreground Segmentation

    DEFF Research Database (Denmark)

    Huerta, Ivan; Holte, Michael Boelstoft; Moeslund, Thomas B.

    2015-01-01

    chrominance angle and brightness distortions are analysed for each potential shadow region for detecting the umbra shadow regions. Our second contribution refines even further the segmentation results: a tracking-based top-down approach increases the performance of our bottom-up chromatic shadow detection...

  17. SHADOW PROCESSES INSTATE BUDGET: CURRENT CONDITION AND DETERMINING FACTORS

    Directory of Open Access Journals (Sweden)

    Z. Varnalii

    2014-12-01

    Full Text Available The most significant factors that move state budget into the shadow are determined. Current condition of shadow processes in state budget is highlighted. The paper also provides an analysis of relationship between political processes and shadow economy in public sector of Ukraine.

  18. Innovation as improvisation 'in the shadow'

    DEFF Research Database (Denmark)

    Larsen, Henry; Bogers, Marcel

    2014-01-01

    — happening ‘below the radar’ — which may unpredictably offer windows of opportunity to enable change. We show that innovation often emerges as ‘shadow themes’, experienced as subversive by those involved in the moments of interaction. While these themes are embedded in informal conversations and processes...

  19. ELL Shadowing as a Catalyst for Change

    Science.gov (United States)

    Soto, Ivannia

    2012-01-01

    What if you could barely understand what your teacher was saying? Imagine working mostly independently and silently, with limited opportunities to interact with others. ELL shadowing helps teachers better understand the classroom experience from an English language learner's point of view. The author describes how to implement this easily…

  20. Job Shadowing Introduces the Realities of Manufacturing

    Science.gov (United States)

    Frawley, Thomas A.

    2009-01-01

    Engineers and skilled tradesmen stood side by side with executives and politicians as Liverpool High School technology teacher Dan Drogo welcomed parents to a one-of-a-kind graduation ceremony at New Process Gear in Syracuse, New York. The manufacturing shadow program had immersed 25 high school students in an intensive five-week experience inside…

  1. Hunting the Shadow, Catching the Light

    DEFF Research Database (Denmark)

    Toft, Anne Elisabeth; Nielsen, Torben

    2009-01-01

    From 28 October to 6 November 2009 twenty-one 3rd year students in interior design from Central Academy of Fine Arts (CAFA), School of Architecture, Beijing participated in the workshop Hunting the Shadow - Catching the Light. The workshop was conceived and led by the Danish architects Torben...

  2. Maintenance features of the Compact Ignition Tokamak fusion reactor

    Energy Technology Data Exchange (ETDEWEB)

    Spampinato, P.T.; Hager, E.R.

    1987-01-01

    The Compact Ignition Tokamak (CIT) is envisaged to be the next experimental machine in the US Fusion Program. Its use of deuterium/tritium fuel requires the implementation of remote handling technology for maintenance and disassembly operations. The reactor is surrounded by a close-proximity nuclear shield which is designed to permit personnel access within the test cell, one day after shutdown. With the shield in place, certain maintenance activities in the cell may be done hands-on. Maintenance on the reactor is accomplished remotely using a boom-mounted manipulator after disassembling the shield. Maintenance within the plasma chamber is accomplished with two articulated boom manipulators that are capable of operating in a vacuum environment. They are stored in a vacuum enclosure behind movable shield plugs.

  3. Shadow Radiation Shield Required Thickness Estimation for Space Nuclear Power Units

    Science.gov (United States)

    Voevodina, E. V.; Martishin, V. M.; Ivanovsky, V. A.; Prasolova, N. O.

    The paper concerns theoretical possibility of visiting orbital transport vehicles based on nuclear power unit and electric propulsion system on the Earth's orbit by astronauts to maintain work with payload from the perspective of radiation safety. There has been done estimation of possible time of the crew's staying in the area of payload of orbital transport vehicles for different reactor powers, which is a consistent part of nuclear power unit.

  4. Satellite Shadow Modeling and Algorithm of Satellite Shadow Parameters for GNSS

    Directory of Open Access Journals (Sweden)

    DU Lan

    2016-11-01

    Full Text Available The satellite shadow parameters can be numerically calculated with high accuracy from the positions of the sun, the earth and the specific satellite. Unfortunately, it is difficult for the numerical calculation to give a general profile of the variations and distributions of these parameters for some certain types of orbital spacecraft. A satellite shadow model was presented based on the spatial view at the altitude of the satellite and the correlative geometry amongst the sun, the earth and the satellite. Firstly, the size and location of the satellite shadow were determined by the semi-major axis of the satellite orbit and the annual motion of the apparent sun, respectively. Secondly, the computing formulae of the satellite shadow parameters were derived, together with the correction formulae for the long-term prediction of the parameters due to oblateness perturbation, etc. Examinations on the three types of orbits for the BeiDou navigation constellation show that the proposed satellite shadow model and its shadow parameters computing formulae can provide a prompt profile of the eclipse parameters for the medium-high altitude circular orbit satellites.

  5. Cosmic Ray Sun Shadow in Soudan 2 Underground Muon Flux

    OpenAIRE

    Soudan 2 Collaboration

    1999-01-01

    The absorption of cosmic rays by the sun produces a shadow at the earth. The angular offset and broadening of the shadow are determined by the magnitude and structure of the interplanetary magnetic field (IPMF) in the inner solar system. We report the first measurement of the solar cosmic ray shadow by detection of deep underground muon flux in observations made during the entire ten-year interval 1989 to 1998. The sun shadow varies significantly during this time, with a $3.3\\sigma$ shadow ob...

  6. Ultrasonic detection of calcification in gallstones: "the reverberation shadow".

    Science.gov (United States)

    Parulekar, S G

    1984-03-01

    Observation of reverberations within a gallstone shadow (the "reverberation shadow") resulted in this study. Reverberation shadow was seen in sonograms of 27 patients with gallstones and three patients with milk of calcium bile. Calcification within gallstones was demonstrated by radiography or computed tomography in 22 of the 27 patients with gallstones, associated with the reverberation shadow. Whether the remaining five patients had calcified gallstones remains unknown. This study suggests that the reverberation shadow produced by gallstones indicates the presence of calcification within the gallstones.

  7. SmartShadow models and methods for pervasive computing

    CERN Document Server

    Wu, Zhaohui

    2013-01-01

    SmartShadow: Models and Methods for Pervasive Computing offers a new perspective on pervasive computing with SmartShadow, which is designed to model a user as a personality ""shadow"" and to model pervasive computing environments as user-centric dynamic virtual personal spaces. Just like human beings' shadows in the physical world, it follows people wherever they go, providing them with pervasive services. The model, methods, and software infrastructure for SmartShadow are presented and an application for smart cars is also introduced.  The book can serve as a valuable reference work for resea

  8. Do Elementary Science Methods Textbooks Promote Understanding of Shadows?

    Directory of Open Access Journals (Sweden)

    Lloyd H. Barrow

    2016-02-01

    Full Text Available Elementary science methods textbooks can be an important resource for future elementary teachers of science. Since shadows are a common topic in elementary school and Next Generation Science Standards (NGSS Lead States, 2013. A series of ten shadows concepts were formed into a learning progression by Wizman and Fortus (2007. For this research, ten science methods textbook were read and analyzed about how each of the shadow concepts were addressed. These methods textbooks focused on a limited number of shadow concepts. Consequently, as a future reference, they are very limited in addressing all ten shadow concepts.

  9. Morphometry of terrestrial shield volcanoes

    Science.gov (United States)

    Grosse, Pablo; Kervyn, Matthieu

    2018-03-01

    Shield volcanoes are described as low-angle edifices built primarily by the accumulation of successive lava flows. This generic view of shield volcano morphology is based on a limited number of monogenetic shields from Iceland and Mexico, and a small set of large oceanic islands (Hawaii, Galápagos). Here, the morphometry of 158 monogenetic and polygenetic shield volcanoes is analyzed quantitatively from 90-meter resolution SRTM DEMs using the MORVOLC algorithm. An additional set of 24 lava-dominated 'shield-like' volcanoes, considered so far as stratovolcanoes, are documented for comparison. Results show that there is a large variation in shield size (volumes from 0.1 to > 1000 km3), profile shape (height/basal width (H/WB) ratios mostly from 0.01 to 0.1), flank slope gradients (average slopes mostly from 1° to 15°), elongation and summit truncation. Although there is no clear-cut morphometric difference between shield volcanoes and stratovolcanoes, an approximate threshold can be drawn at 12° average slope and 0.10 H/WB ratio. Principal component analysis of the obtained database enables to identify four key morphometric descriptors: size, steepness, plan shape and truncation. Hierarchical cluster analysis of these descriptors results in 12 end-member shield types, with intermediate cases defining a continuum of morphologies. The shield types can be linked in terms of growth stages and shape evolution, related to (1) magma composition and rheology, effusion rate and lava/pyroclast ratio, which will condition edifice steepness; (2) spatial distribution of vents, in turn related to the magmatic feeding system and the tectonic framework, which will control edifice plan shape; and (3) caldera formation, which will condition edifice truncation.

  10. Automated detection and removal of cloud shadows on HICO images

    Science.gov (United States)

    Amin, Ruhul; Gould, Richard; Hou, Weilin; Lee, Zhongping; Arnone, Robert

    2011-06-01

    Clouds cause a serious problem for optical satellite sensors. Clouds not only conceal the ground, they also cast shadows, which cause either a reduction or total loss of information in an image, by reducing the illumination falling on the shadowed pixels. Ocean color bio-optical inversion algorithms rely on measurements of remote sensing reflectance (Rrs (λ )) at each pixel. If shadows are not removed properly across a scene, erroneous Rrs (λ) values will be calculated for the shadowed pixels, leading to incorrect retrievals of ocean color products such as chlorophyll. The cloud shadow issue becomes significant especially for high-resolution sensors such as the Hyperspectral Imager for the Coastal Ocean (HICO). On the other hand, the contrast of pixels in and outside a shadow provides opportunities to remove atmospheric contributions for ocean color remote sensing. Although identifying cloud is relatively straightforward using simple brightness thresholds, identifying their shadows especially over water is quite challenging because the brightness of the shadows is very close to the brightness of neighboring sunny regions especially in deep waters. In this study, we present automated procedures for our recently proposed cloud shadow detection technique called the Cloud Shadow Algorithm (CSA) and Lee et al. (2007) cloud and shadow atmospheric correction algorithm. We apply both automated procedures to HICO imagery and show examples of the results.

  11. Exposing image forgery by detecting consistency of shadow.

    Science.gov (United States)

    Ke, Yongzhen; Qin, Fan; Min, Weidong; Zhang, Guiling

    2014-01-01

    We propose two tampered image detection methods based on consistency of shadow. The first method is based on texture consistency of shadow for the first kind of splicing image, in which the shadow as well as main body is copied and pasted from another image. The suspicious region including shadow and nonshadow is first selected. Then texture features of the shadow region and the nonshadow region are extracted. Last, correlation function is used to measure the similarity of the two texture features. By comparing the similarity, we can judge whether the image is tampered. Due to the failure in detecting the second kind of splicing image, in which main body, its shadow, and surrounding regions are copied and pasted from another image, another method based on strength of light source of shadows is proposed. The two suspicious shadow regions are first selected. Then an efficient method is used to estimate the strength of light source of shadow. Last, the similarity of strength of light source of two shadows is measured by correlation function. By combining the two methods, we can detect forged image with shadows. Experimental results demonstrate that the proposed methods are effective despite using simplified model compared with the existing methods.

  12. Exposing Image Forgery by Detecting Consistency of Shadow

    Directory of Open Access Journals (Sweden)

    Yongzhen Ke

    2014-01-01

    Full Text Available We propose two tampered image detection methods based on consistency of shadow. The first method is based on texture consistency of shadow for the first kind of splicing image, in which the shadow as well as main body is copied and pasted from another image. The suspicious region including shadow and nonshadow is first selected. Then texture features of the shadow region and the nonshadow region are extracted. Last, correlation function is used to measure the similarity of the two texture features. By comparing the similarity, we can judge whether the image is tampered. Due to the failure in detecting the second kind of splicing image, in which main body, its shadow, and surrounding regions are copied and pasted from another image, another method based on strength of light source of shadows is proposed. The two suspicious shadow regions are first selected. Then an efficient method is used to estimate the strength of light source of shadow. Last, the similarity of strength of light source of two shadows is measured by correlation function. By combining the two methods, we can detect forged image with shadows. Experimental results demonstrate that the proposed methods are effective despite using simplified model compared with the existing methods.

  13. Politics, Time and Space in the Era of Shadow Banking

    DEFF Research Database (Denmark)

    Bryan, Dick; Rafferty, Michael; Wigan, Duncan

    2016-01-01

    In the wake of the Global Financial Crisis, there has been an understandable focus on the financial fragility and contagion aspects of shadow banking. This article argues that shadow banking is important for another set of reasons. It has been well established that shadow banking permits the tran......In the wake of the Global Financial Crisis, there has been an understandable focus on the financial fragility and contagion aspects of shadow banking. This article argues that shadow banking is important for another set of reasons. It has been well established that shadow banking permits...... challenging earlier spatio-temporal concepts of finance, and the regulatory/jurisdictional order built on them. The article suggests that the longer term significance of shadow banking may not just be its role in financial crisis, or even tax and regulatory arbitrage, but that it was here that innovative...

  14. Model Compaction Equation

    African Journals Online (AJOL)

    compaction are two parameters that indicate the degree of compaction in sandstones. When the values are low, the sands are undercompacted, but when they are high the sands are compacted. A number of equations relating porosity and depth in sandstones have been published (Athy,. 1930; Hubbert and Rubey, 1959; ...

  15. SNF shipping cask shielding analysis

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, J.O.; Pace, J.V. III

    1996-01-01

    The Waste Management and Remedial Action Division has planned a modification sequence for storage facility 7827 in the Solid Waste Storage Area (SWSA). The modification cycle is: (1) modify an empty caisson, (2) transfer the spent nuclear fuel (SNF) of an occupied caisson to a hot cell in building 3525 for inspection and possible repackaging, and (3) return the package to the modified caisson in the SWSA. Although the SNF to be moved is in the solid form, it has different levels of activity. Thus, the following 5 shipping casks will be available for the task: the Loop Transport Carrier, the In- Pile Loop LITR HB-2 Carrier, the 6.5-inch HRLEL Carrier, the HFIR Hot Scrap Carrier, and the 10-inch ORR Experiment Removal Shield Cask. This report describes the shielding tasks for the 5 casks: determination of shielding characteristics, any streaming avenues, estimation of thermal limits, and shielding calculational uncertainty for use in the transportation plan.

  16. Fuzzy split and merge for shadow detection

    Directory of Open Access Journals (Sweden)

    Remya K. Sasi

    2015-03-01

    Full Text Available Presence of shadow in an image often causes problems in computer vision applications such as object recognition and image segmentation. This paper proposes a method to detect the shadow from a single image using fuzzy split and merge approach. Split and merge is a classical algorithm used in image segmentation. Predicate function in the classical approach is replaced by a Fuzzy predicate in the proposed approach. The method follows a top down approach of recursively splitting an image into homogeneous quadtree blocks, followed by a bottom up approach by merging adjacent unique regions. The method has been compared with previous approaches and found to be better in performance in terms of accuracy.

  17. Fading and Shadowing in Wireless Systems

    CERN Document Server

    Shankar, P Mohana

    2012-01-01

    In recent decades, growth in the field of wireless communications has led to an exponential rise in the number of journals catering to the research community. Still unmet, however, is the need to fully and comprehensively understand the effects of channel degradation brought on by the statistical fluctuations in the channel. These fluctuations mainly manifest as variations in signal power observed in the channel generally modeled using a variety of probability distributions, both in straight forms as well as in compound forms. While the former might explain some of the effects, it is the latter, namely, the compound models, which incorporate both short term and long term power fluctuations in the channel, explain the much more complex nature of the signals in these channels. Fading and Shadowing in Wireless Systems offers a pedagogical approach to the topic, with insight into the modeling and analysis of fading and shadowing. Beginning with statistical background and digital communications, the book is formul...

  18. Composite Aerogel Multifoil Protective Shielding

    Science.gov (United States)

    Jones, Steven M.

    2013-01-01

    New technologies are needed to survive the temperatures, radiation, and hypervelocity particles that exploration spacecraft encounter. Multilayer insulations (MLIs) have been used on many spacecraft as thermal insulation. Other materials and composites have been used as micrometeorite shielding or radiation shielding. However, no material composite has been developed and employed as a combined thermal insulation, micrometeorite, and radiation shielding. By replacing the scrims that have been used to separate the foil layers in MLIs with various aerogels, and by using a variety of different metal foils, the overall protective performance of MLIs can be greatly expanded to act as thermal insulation, radiation shielding, and hypervelocity particle shielding. Aerogels are highly porous, low-density solids that are produced by the gelation of metal alkoxides and supercritical drying. Aerogels have been flown in NASA missions as a hypervelocity particle capture medium (Stardust) and as thermal insulation (2003 MER). Composite aerogel multifoil protective shielding would be used to provide thermal insulation, while also shielding spacecraft or components from radiation and hypervelocity particle impacts. Multiple layers of foil separated by aerogel would act as a thermal barrier by preventing the transport of heat energy through the composite. The silica aerogel would act as a convective and conductive thermal barrier, while the titania powder and metal foils would absorb and reflect the radiative heat. It would also capture small hypervelocity particles, such as micrometeorites, since it would be a stuffed, multi-shock Whipple shield. The metal foil layers would slow and break up the impacting particles, while the aerogel layers would convert the kinetic energy of the particles to thermal and mechanical energy and stop the particles.

  19. LIGHT, SHADOW AND WIND IN BUILDING DESIGN.

    OpenAIRE

    Katyarmal, Preeti P

    2008-01-01

    Design is about understanding a space. It is about integration of light and air in building design. It is about light, shadow, reflection. It is about wind, its movement and escape. Through designing this project I was able to explore how sun, wind and light can be used effectively in a building design, in my project, in an office environment. The fire, the Light; the energy is the inspiration behind the origin of Architecture. Energy brings architecture into the world of...

  20. Integral Face Shield Concept for Firefighter's Helmet

    Science.gov (United States)

    Abeles, F.; Hansberry, E.; Himel, V.

    1982-01-01

    Stowable face shield could be made integral part of helmet worn by firefighters. Shield, made from same tough clear plastic as removable face shields presently used, would be pivoted at temples to slide up inside helmet when not needed. Stowable face shield, being stored in helmet, is always available, ready for use, and is protected when not being used.

  1. Measuring space radiation shielding effectiveness

    Science.gov (United States)

    Bahadori, Amir; Semones, Edward; Ewert, Michael; Broyan, James; Walker, Steven

    2017-09-01

    Passive radiation shielding is one strategy to mitigate the problem of space radiation exposure. While space vehicles are constructed largely of aluminum, polyethylene has been demonstrated to have superior shielding characteristics for both galactic cosmic rays and solar particle events due to the high hydrogen content. A method to calculate the shielding effectiveness of a material relative to reference material from Bragg peak measurements performed using energetic heavy charged particles is described. Using accelerated alpha particles at the National Aeronautics and Space Administration Space Radiation Laboratory at Brookhaven National Laboratory, the method is applied to sample tiles from the Heat Melt Compactor, which were created by melting material from a simulated astronaut waste stream, consisting of materials such as trash and unconsumed food. The shielding effectiveness calculated from measurements of the Heat Melt Compactor sample tiles is about 10% less than the shielding effectiveness of polyethylene. Shielding material produced from the astronaut waste stream in the form of Heat Melt Compactor tiles is therefore found to be an attractive solution for protection against space radiation.

  2. Measuring space radiation shielding effectiveness

    Directory of Open Access Journals (Sweden)

    Bahadori Amir

    2017-01-01

    Full Text Available Passive radiation shielding is one strategy to mitigate the problem of space radiation exposure. While space vehicles are constructed largely of aluminum, polyethylene has been demonstrated to have superior shielding characteristics for both galactic cosmic rays and solar particle events due to the high hydrogen content. A method to calculate the shielding effectiveness of a material relative to reference material from Bragg peak measurements performed using energetic heavy charged particles is described. Using accelerated alpha particles at the National Aeronautics and Space Administration Space Radiation Laboratory at Brookhaven National Laboratory, the method is applied to sample tiles from the Heat Melt Compactor, which were created by melting material from a simulated astronaut waste stream, consisting of materials such as trash and unconsumed food. The shielding effectiveness calculated from measurements of the Heat Melt Compactor sample tiles is about 10% less than the shielding effectiveness of polyethylene. Shielding material produced from the astronaut waste stream in the form of Heat Melt Compactor tiles is therefore found to be an attractive solution for protection against space radiation.

  3. The SHIELD11 Computer Code

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, W

    2005-02-02

    SHIELD11 is a computer code for performing shielding analyses around a high-energy electron accelerator. It makes use of simple analytic expressions for the production and attenuation of photons and neutrons resulting from electron beams striking thick targets, such as dumps, stoppers, collimators, and other beam devices. The formulae in SHIELD11 are somewhat unpretentious in that they are based on the extrapolation (scaling) of experimental data using rather simple physics ideas. Because these scaling methods have only been tested over a rather limited set of conditions--namely, 1-15 GeV electrons striking 10-20 radiation lengths of iron--a certain amount of care and judgment must be exercised whenever SHIELD11 is used. Nevertheless, for many years these scaling methods have been applied rather successfully to a large variety of problems at SLAC, as well as at other laboratories throughout the world, and the SHIELD11 code has been found to be a fast and convenient tool. In this paper we present, without extensive theoretical justification or experimental verification, the five-component model on which the SHIELD11 code is based. Our intent is to demonstrate how to use the code by means of a few simple examples. References are provided that are considered to be essential for a full understanding of the model. The code itself contains many comments to provide some guidance for the informed user, who may wish to improve on the model.

  4. Nebkha flow dynamics and shadow dune formation

    Science.gov (United States)

    Hesp, Patrick A.; Smyth, Thomas A. G.

    2017-04-01

    In this study, wind flow is simulated via CFD over five 'nebkha' dune forms that range in shape from a cone, to a hemisphere (approximately) and to a dome in order to examine the structure of the wake zone formed downwind and the effect on the leeward flow separation zone and shadow dune formation. Dune height was fixed at 0.5 m while the nebkha diameter increased in 0.25 m increments from 0.5 m to 1.5 m and aspect ratio (h/D) from 1.0 to 0.3. The mean flow comprises an upwind region of reduced velocity which expands as nebkha width increases, high velocity marginal wings, and paired counter-rotating reversing vortices leeward of the nebkha. The point at which flow separation occurs moves further downwind as the nebkha diameter increases. The core regions of the reversing vortices are situated further downwind behind the smaller nebkha than in the case of the larger nebkha. These factors in combination allow for higher velocity perturbations (TKE) and narrower wake behind the smaller nebkha, and the suppression of downwind wake development in the case of the increasingly larger nebkha. Shadow dune length increases as nebkha width increases for lower incident velocity flow and is barely affected by nebkha width at higher flows. The extent of the leeward separation or wake zone, and hence shadow dune length, more strongly varies as a function of wind velocity.

  5. Infant Perception of Incongruent Shapes in Cast Shadows

    Directory of Open Access Journals (Sweden)

    Kazuki Sato

    2015-04-01

    Full Text Available A cast shadow occurs when an object blocks the light from an illumination and projects a dark region onto a surface. Previous studies have reported that adults are slower to identify an object when the object has an incongruent cast shadow than when it has a congruent cast shadow (Castiello, 2001. Here, we used the familiarization-novelty preference procedure to examine whether 5- to 8-month-old infants could detect the relationship between object shapes and cast shadows. In Experiment 1, we examined the infants' ability to detect incongruency between objects and cast shadows. Results showed that 7- to 8-month olds could detect incongruence between the object shapes and the cast shadows, whereas 5- to 6-month olds did not. Yet, our control experiment showed that infants could not detect this incongruence from stimuli in which a white outline had been added to the original cast shadow to decrease the possibility of it being perceived as a cast shadow (Experiment 2. The results of these experiments demonstrate that 7- to 8-month olds responded to the congruence of cast shadows and to consistent contrast polarity between the cast shadow and its background.

  6. Reduced atomic shadowing in HiPIMS: Role of the thermalized metal ions

    Science.gov (United States)

    Oliveira, João Carlos; Ferreira, Fábio; Anders, André; Cavaleiro, Albano

    2018-03-01

    In magnetron sputtering, the ability to tailor film properties depends primarily on the control of the flux of particles impinging on the growing film. Among deposition mechanisms, the shadowing effect leads to the formation of a rough surface and a porous, columnar microstructure. Re-sputtered species may be re-deposited in the valleys of the films surface and thereby contribute to a reduction of roughness and to fill the underdense regions. Both effects are non-local and they directly compete to shape the final properties of the deposited films. Additional control of the bombarding flux can be obtained by ionizing the sputtered flux, because ions can be controlled with respect to their energy and impinging direction, such as in High-Power Impulse Magnetron Sputtering (HiPIMS). In this work, the relation between ionization of the sputtered species and thin film properties is investigated in order to identify the mechanisms which effectively influence the shadowing effect in Deep Oscillation Magnetron Sputtering (DOMS), a variant of HiPIMS. The properties of two Cr films deposited using the same averaged target power by d.c. magnetron sputtering and DOMS have been compared. Additionally, the angle distribution of the Cr species impinging on the substrate was simulated using Monte Carlo-based programs while the energy distribution of the energetic particles bombarding the substrate was evaluated by energy-resolved mass analysis. It was found that the acceleration of the thermalized chromium ions at the substrate sheath in DOMS significantly reduces the high angle component of their impinging angle distribution and, thus, efficiently reduces atomic shadowing. Therefore, a high degree of ionization in HiPIMS results in almost shadowing effect-free film deposition and allows us to deposit dense and compact films without the need of high energy particle bombardment during growth.

  7. On the interaction between two oppositely signed, shielded, monopolar vortices

    DEFF Research Database (Denmark)

    Schmidt, M.R.; Beckers, M.; Nielsen, A.H.

    1998-01-01

    solutions of the two-dimensional Navier-Stokes equations. A comparative study between the laboratory experiments and numerical simulations is performed. The vorticity distribution measured in the early stage of the evolution in the laboratory is used as initial data for the simulations, and an additional...... damping term in the Navier-Stokes equations, that accounts for the vertical diffusion in the laboratory experiments, is used. The results show that, depending on the initial separation between the vortices, the shields of the monopoles are peeled off and indeed a compact dipole with a linear (omega...

  8. Influence of shadow removal on image classification in riverine environments.

    Science.gov (United States)

    Filippi, Anthony M; Güneralp, İnci

    2013-05-15

    Shadows in remote-sensor images can yield marked errors in classification of riverine environments. We propose use of a modified shadow-removal algorithm as a preprocessing step for remote-sensing image classification of riverine landscapes. To accommodate characterization of spatially complex river features in the image, we investigate an illumination suppression-based shadow-removal algorithm, modified to include a user-defined tiling approach. We quantitatively evaluate the influence of shadow removal from aerial photography on classification accuracy as such studies are currently lacking. Experimental results demonstrate that this modified shadow-removal method significantly increases classification accuracy and improves detection of small river channels partially obscured by shadow.

  9. Clustered deep shadow maps for integrated polyhedral and volume rendering

    KAUST Repository

    Bornik, Alexander

    2012-01-01

    This paper presents a hardware-accelerated approach for shadow computation in scenes containing both complex volumetric objects and polyhedral models. Our system is the first hardware accelerated complete implementation of deep shadow maps, which unifies the computation of volumetric and geometric shadows. Up to now such unified computation was limited to software-only rendering . Previous hardware accelerated techniques can handle only geometric or only volumetric scenes - both resulting in the loss of important properties of the original concept. Our approach supports interactive rendering of polyhedrally bounded volumetric objects on the GPU based on ray casting. The ray casting can be conveniently used for both the shadow map computation and the rendering. We show how anti-aliased high-quality shadows are feasible in scenes composed of multiple overlapping translucent objects, and how sparse scenes can be handled efficiently using clustered deep shadow maps. © 2012 Springer-Verlag.

  10. The shadow of black holes an analytic description

    CERN Document Server

    Grenzebach, Arne

    2016-01-01

    This book introduces an analytic method to describe the shadow of black holes. As an introduction, it presents a survey of the attempts to observe the shadow of galactic black holes. Based on a detailed discussion of the Plebański–Demiański class of space-times, the book derives analytical formulas for the photon regions and for the boundary curve of the shadow as seen by an observer in the domain of outer communication. It also analyzes how the shadow depends on the motion of the observer. For all cases, the photon regions and shadows are visualized for various values of the parameters. Finally, it considers how the analytical formulas can be used for calculating the horizontal and vertical angular diameters of the shadow, and estimates values for the black holes at the centers of our Galaxy near Sgr A* and of the neighboring galaxy M87.

  11. PRECONDITIONS AND DETERMINING CAUSES OF THE SHADOW ECONOMY IN UKRAINE

    Directory of Open Access Journals (Sweden)

    Z. Varnalii

    2014-03-01

    Full Text Available The article analyzes the main processes that led to the high level of the economy shadowing. The historical aspects of the formation of the shadow economy in Ukraine are highlighted. The socio-economic aspects of the shadow economy of Ukraine causality are discussed. The theoretical contribution of foreign and domestic researchers on the preconditions of formation of the shadow economy in transition economies is studied. Theoretical perspective on the factors of the shadowing processes in the economy of Ukraine from the standpoint of modern scientific researches is analyzed. The paper also provides scientific vectors for further development of researches aimed at studying the causes and preconditions of the shadow economy.

  12. Electromagnetic interference shielding properties and mechanisms of chemically reduced graphene aerogels

    Energy Technology Data Exchange (ETDEWEB)

    Bi, Shuguang [Temasek Laboratories, Nanyang Technological University, 50 Nanyang Drive, 637553 (Singapore); Zhang, Liying, E-mail: LY.Zhang@ntu.edu.sg [Temasek Laboratories, Nanyang Technological University, 50 Nanyang Drive, 637553 (Singapore); Mu, Chenzhong [School of Material Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore); Liu, Ming, E-mail: LIUMING@ntu.edu.sg [Temasek Laboratories, Nanyang Technological University, 50 Nanyang Drive, 637553 (Singapore); Hu, Xiao [Temasek Laboratories, Nanyang Technological University, 50 Nanyang Drive, 637553 (Singapore); School of Material Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore)

    2017-08-01

    Graphical abstract: The electromagnetic interference shielding behavior and proposed mechanisms of ultralight free-standing 3D graphene aerogels. - Highlights: • The electromagnetic interference (EMI) shielding properties and mechanisms of ultralight 3D graphene aerogels (GAs) were systematically studied with respect to both the unique porous network and the intrinsic properties of the graphene sheets. • Thickness of the shielding material played a critical role on EMI SE. • By compressing the porous GAs into compact film didnt increase the EMI SE despite the increased electrical conductivity and connectivity. EMI SE is highly dependent on the effective amounts of the materials response to the EM waves. - Abstract: Graphene was recently demonstrated to exhibit excellent electromagnetic interference (EMI) shielding performance. In this work, ultralight (∼5.5 mg/cm{sup 3}) graphene aerogels (GAs) were fabricated through assembling graphene oxide (GO) using freeze-drying followed by a chemical reduction method. The EMI shielding properties and mechanisms of GAs were systematically studied with respect to the intrinsic properties of the reduced graphene oxide (rGO) sheets and the unique porous network. The EMI shielding effectiveness (SE) of GAs was increased from 20.4 to 27.6 dB when the GO was reduced by high concentration of hydrazine vapor. The presence of more sp{sup 2} graphitic lattice and free electrons from nitrogen atoms resulted in the enhanced EMI SE. Absorption was the dominant shielding mechanism of GAs. Compressing the highly porous GAs into compact thin films did not change the EMI SE, but shifted the dominant shielding mechanism from absorption to reflection.

  13. Corruption and the Shadow Economy: An Empirical Analysis

    OpenAIRE

    Dreher, Axel; Friedrich G. Schneider

    2006-01-01

    This paper analyzes the influence of the shadow economy on corruption and vice versa. We hypothesize that corruption and the shadow economy are substitutes in high income countries while they are complements in low income countries. The hypotheses are tested for a cross-section of 98 countries. Our results show that there is no robust relationship between corruption and the size of the shadow economy when perceptions-based indices of corruption are used. Employing an index of corruption based...

  14. Preliminary Evaluation of Convective Heat Transfer in a Water Shield for a Surface Power Reactor

    Science.gov (United States)

    Pearson J. Boise; Reid, Robert S.

    2007-01-01

    As part of the Vision for Space Exploration, the end of the next decade will bring man back to the surface of the moon. A crucial issue for the establishment of human presence on the moon will be the availability of compact power sources. This presence could require greater than 10's of kWt's in follow on years. Nuclear reactors are well suited to meet the needs for power generation on the lunar or Martian surface. Radiation shielding is a key component of any surface power reactor system. Several competing concepts exist for lightweight, safe, robust shielding systems such as a water shield, lithium hydride (LiH), and boron carbide. Water offers several potential advantages, including reduced cost, reduced technical risk, and reduced mass. Water has not typically been considered for space reactor applications because of the need for gravity to fix the location of any vapor that could form radiation streaming paths. The water shield concept relies on the predictions of passive circulation of the shield water by natural convection to adequately cool the shield. This prediction needs to be experimentally evaluated, especially for shields with complex geometries. NASA Marshall Space Flight Center has developed the experience and facilities necessary to do this evaluation in its Early Flight Fission - Test Facility (EFF-TF).

  15. Shadow Segmentation and Augmentation Using á-overlay Models that Account for Penumbra

    DEFF Research Database (Denmark)

    Nielsen, Michael; Madsen, Claus B.

    2006-01-01

    that an augmented virtual object can cast an exact shadow. The penumbras (half-shadows) must be taken into account so that we can model the soft shadows.We hope to achieve this by modelling the shadow regions (umbra and penumbra alike) with a transparent overlay. This paper reviews the state-of-the-art shadow...

  16. Automatic Shadow Detection and Removal from a Single Image.

    Science.gov (United States)

    Khan, Salman H; Bennamoun, Mohammed; Sohel, Ferdous; Togneri, Roberto

    2016-03-01

    We present a framework to automatically detect and remove shadows in real world scenes from a single image. Previous works on shadow detection put a lot of effort in designing shadow variant and invariant hand-crafted features. In contrast, our framework automatically learns the most relevant features in a supervised manner using multiple convolutional deep neural networks (ConvNets). The features are learned at the super-pixel level and along the dominant boundaries in the image. The predicted posteriors based on the learned features are fed to a conditional random field model to generate smooth shadow masks. Using the detected shadow masks, we propose a Bayesian formulation to accurately extract shadow matte and subsequently remove shadows. The Bayesian formulation is based on a novel model which accurately models the shadow generation process in the umbra and penumbra regions. The model parameters are efficiently estimated using an iterative optimization procedure. Our proposed framework consistently performed better than the state-of-the-art on all major shadow databases collected under a variety of conditions.

  17. Interactive removal and ground truth for difficult shadow scenes

    OpenAIRE

    Gong, Han; Cosker, Darren

    2016-01-01

    A user-centric method for fast, interactive, robust, and high-quality shadow removal is presented. Our algorithm can perform detection and removal in a range of difficult cases, such as highly textured and colored shadows. To perform detection, an on-the-fly learning approach is adopted guided by two rough user inputs for the pixels of the shadow and the lit area. After detection, shadow removal is performed by registering the penumbra to a normalized frame, which allows us efficient estimati...

  18. Radiation Shielding Materials and Containers Incorporating Same

    Energy Technology Data Exchange (ETDEWEB)

    Mirsky, Steven M.; Krill, Stephen J.; and Murray, Alexander P.

    2005-11-01

    An improved radiation shielding material and storage systems for radioactive materials incorporating the same. The PYRolytic Uranium Compound (''PYRUC'') shielding material is preferably formed by heat and/or pressure treatment of a precursor material comprising microspheres of a uranium compound, such as uranium dioxide or uranium carbide, and a suitable binder. The PYRUC shielding material provides improved radiation shielding, thermal characteristic, cost and ease of use in comparison with other shielding materials. The shielding material can be used to form containment systems, container vessels, shielding structures, and containment storage areas, all of which can be used to house radioactive waste. The preferred shielding system is in the form of a container for storage, transportation, and disposal of radioactive waste. In addition, improved methods for preparing uranium dioxide and uranium carbide microspheres for use in the radiation shielding materials are also provided.

  19. Compaction behaviour of soils

    OpenAIRE

    Kurucuk, Nurses

    2017-01-01

    Soil compaction is widely applied in geotechnical engineering practice. It is used to maximise the dry density of soils to reduce subsequent settlement under working loads or to reduce the permeability of soils. The durability and stability of structures are highly related to the appropriate compaction achievement. The structural failure of roads and airfields, and the damage caused by foundation settlement can often be traced back to the failure in achieving adequate compaction. For that rea...

  20. Self-Compacting Concrete

    OpenAIRE

    Okamura, Hajime; Ouchi, Masahiro

    2003-01-01

    Self-compacting concrete was first developed in 1988 to achieve durable concrete structures. Since then, various investigations have been carried out and this type of concrete has been used in practical structures in Japan, mainly by large construction companies. Investigations for establishing a rational mix-design method and self-compactability testing methods have been carried out from the viewpoint of making self-compacting concrete a standard concrete.

  1. Thin-film growth dynamics with shadowing effects by a phase-field approach

    Science.gov (United States)

    Salvalaglio, Marco; Backofen, Rainer; Voigt, Axel

    2016-12-01

    Shadowing effects during the growth of nano- and microstructures are crucial for the realization of several technological applications. They are given by the shielding of the incoming material flux provided by the growing structures themselves. Their features have been deeply investigated by theoretical approaches, revealing important information to support experimental activities. However, comprehensive investigations able to follow every stage of the growth processes as a whole, particularly useful to design and understand targeted experiments, are still challenging. In this work, we study the thin-film growth dynamics by means of a diffuse interface approach accounting for both deposition with shadowing effects and surface diffusion driven by the minimization of the surface energy. In particular, we introduce the coupling between a phase-field model and the detailed calculation of the incoming material flux at the surface deposited from vacuum or vapor phase in the ballistic regime. This allows us to finely reproduce the realistic morphological evolution during the growth on nonflat substrates, also accounting for different flux distributions. A general assessment of the method, focusing on two-dimensional profiles, is provided thanks to the comparison with a sharp-interface approach for the evolution of the early stages. Then, the long-time-scale dynamics is shown in two and three dimensions, providing a general overview of the features observed during deposition on corrugated surfaces involving flattening, increasing of surface roughness with the growth of columnar structures, and voids formation.

  2. Compact Antenna Range

    Data.gov (United States)

    Federal Laboratory Consortium — Facility consists of a folded compact antenna range including a computer controlled three axis position table, parabolic reflector and RF sources for the measurement...

  3. Compact Polarimetry Potentials

    Science.gov (United States)

    Truong-Loi, My-Linh; Dubois-Fernandez, Pascale; Pottier, Eric

    2011-01-01

    The goal of this study is to show the potential of a compact-pol SAR system for vegetation applications. Compact-pol concept has been suggested to minimize the system design while maximize the information and is declined as the ?/4, ?/2 and hybrid modes. In this paper, the applications such as biomass and vegetation height estimates are first presented, then, the equivalence between compact-pol data simulated from full-pol data and compact-pol data processed from raw data as such is shown. Finally, a calibration procedure using external targets is proposed.

  4. The shadow price of fossil groundwater

    Science.gov (United States)

    Bierkens, Marc F. P.; Reinhard, Stijn; de Bruijn, Jens A.; Wada, Yoshihide

    2017-04-01

    The expansion of irrigated agriculture into areas with limited precipitation and surface water during the growing season has greatly increased the use of fossil groundwater (Wada et al., 2012). As a result, the depletion rate of fossil groundwater resources has shown an increasing rate during the last decades (Wada et al, 2010; Konikow, 2011; Wada et al., 2012; De Graaf et al. 2015; Ritchy et al., 2015). Although water pricing has been used extensively to stimulate efficient application of water to create maximum value (e.g. Medellín-Azuara et al., 2012; Rinaudo et al., 2012; Dinar et al., 2015), it does not preclude the use of non-renewable water resources. Here, we use a global hydrological model and historical crop production and price data to assess the shadow price of non-renewable or fossil groundwater applied to major crops in countries that use large quantities of fossil groundwater. Our results show that shadow prices for many crops are very low, indicating economically inefficient or even wasteful use of fossil groundwater resources. Using India as an example, we show that small changes in the crop mix could lead to large reductions in fossil groundwater use or alternatively, create additional financial means to invest in water saving technologies. Our study thus provides a hydro-economic basis to further the sustainable use of finite groundwater resources.

  5. Model Compaction Equation

    African Journals Online (AJOL)

    exponential loss of porosity with depth (Ramm et al., 1997). Compaction coefficient and percentage compaction are two .... distribution of overpressure zones in the Niger. Delta in order to further investigate the overpressure. ..... light of the theory of continental drift. Geology Magazine, 105: 385 - 397. Weber, K.J. And E.M. ...

  6. A Quiet Gradient-Coil Set Employing Optimized, Force-Shielded, Distributed Coil Designs

    Science.gov (United States)

    Chapman, B. L. W.; Mansfield, P.

    1995-05-01

    A distributed coil design is described which employs active force shielding to reduce acoustic noise. Both axial and transverse gradients employ sets of distributed pairs of coplanar closed-are loops whose planes are normal to the static magnetic field direction. The resulting gradients are also partially magnetically screened. The design results in an axially compact coil set that provides linear gradients which extend over greater fractions of the enclosed volume than previous designs. The minimal gradient field interaction with the patient inherent in this force-shielded transverse-gradient coil design provides intrinsically safer Gx and Gy gradient fields.

  7. A Novel Radiation Shielding Material Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Radiation shielding simulations showed that epoxy loaded with 10-70% polyethylene would be an excellent shielding material against GCRs and SEPs. Milling produced an...

  8. Shadow edge detection using geometric and photometric features

    NARCIS (Netherlands)

    Gijsenij, A.; Gevers, T.

    2009-01-01

    The detection of shadow and shading edges is a first step towards reducing the imaging effects that are caused by interactions of the light source with surfaces that are in the scene. As most of the algorithms for shadow edge detection use photometric information, geometric information have been

  9. Shadows of Einstein–dilaton–Gauss–Bonnet black holes

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, Pedro V.P., E-mail: pintodacunha@tecnico.ulisboa.pt [Departamento de Física da Universidade de Aveiro and Centre for Research and Development in Mathematics and Applications (CIDMA), Campus de Santiago, 3810-183 Aveiro (Portugal); CENTRA, Departamento de Física, Instituto Superior Técnico, Universidade de Lisboa, Avenida Rovisco Pais 1, 1049, Lisboa (Portugal); Herdeiro, Carlos A.R., E-mail: herdeiro@ua.pt [Departamento de Física da Universidade de Aveiro and Centre for Research and Development in Mathematics and Applications (CIDMA), Campus de Santiago, 3810-183 Aveiro (Portugal); Kleihaus, Burkhard, E-mail: b.kleihaus@uni-oldenburg.de [Institute of Physics, University of Oldenburg, Oldenburg, 26111 (Germany); Kunz, Jutta, E-mail: jutta.kunz@uni-oldenburg.de [Institute of Physics, University of Oldenburg, Oldenburg, 26111 (Germany); Radu, Eugen, E-mail: eugen.radu@ua.pt [Departamento de Física da Universidade de Aveiro and Centre for Research and Development in Mathematics and Applications (CIDMA), Campus de Santiago, 3810-183 Aveiro (Portugal)

    2017-05-10

    We study the shadows of the fully non-linear, asymptotically flat Einstein–dilaton–Gauss–Bonnet (EdGB) black holes (BHs), for both static and rotating solutions. We find that, in all cases, these shadows are smaller than for comparable Kerr BHs, i.e. with the same total mass and angular momentum under similar observation conditions. In order to compare both cases we provide quantitative shadow parameters, observing in particular that the differences in the shadows mean radii are never larger than the percent level. Therefore, generically, EdGB BHs cannot be excluded by (near future) shadow observations alone. On the theoretical side, we find no clear signature of some exotic features of EdGB BHs on the corresponding shadows, such as the regions of negative (Komar, say) energy density outside the horizon. We speculate that this is due to the fact that the Komar energy interior to the light rings (or more precisely, the surfaces of constant radial coordinate that intersect the light rings in the equatorial plane) is always smaller than the ADM mass, and consequently the corresponding shadows are smaller than those of comparable Kerr BHs. The analysis herein provides a clear example that it is the light ring impact parameter, rather than its “size”, that determines a BH shadow.

  10. Reusable High Aspect Ratio 3-D Nickel Shadow Mask.

    Science.gov (United States)

    Shandhi, M M H; Leber, M; Hogan, A; Warren, D J; Bhandari, R; Negi, S

    2017-04-01

    Shadow Mask technology has been used over the years for resistless patterning and to pattern on unconventional surfaces, fragile substrate and biomaterial. In this work, we are presenting a novel method to fabricate high aspect ratio (15:1) three-dimensional (3D) Nickel (Ni) shadow mask with vertical pattern length and width of 1.2 mm and 40 μm respectively. The Ni shadow mask is 1.5 mm tall and 100 μm wide at the base. The aspect ratio of the shadow mask is 15. Ni shadow mask is mechanically robust and hence easy to handle. It is also reusable and used to pattern the sidewalls of unconventional and complex 3D geometries such as microneedles or neural electrodes (such as the Utah array). The standard Utah array has 100 active sites at the tip of the shaft. Using the proposed high aspect ratio Ni shadow mask, the Utah array can accommodate 300 active sites, 200 of which will be along and around the shaft. The robust Ni shadow mask is fabricated using laser patterning and electroplating techniques. The use of Ni 3D shadow mask will lower the fabrication cost, complexity and time for patterning out-of-plane structures.

  11. Shading and shadowing on Canaletto's Piazza San Marco

    NARCIS (Netherlands)

    Wijntjes, M.W.A.; De Ridder, H.

    2014-01-01

    Whereas the 17th century painter Canaletto was a master in linear perspective of the architectural elements, he seems to have had considerable difficulty with linear perspective of shadows. A common trick to avoid shadow perspective problems is to set the (solar) illumination direction parallel to

  12. Asphalted Road Temperature Variations Due to Wind Turbine Cast Shadows

    Directory of Open Access Journals (Sweden)

    Jonay Toledo

    2009-11-01

    Full Text Available The contribution of this paper is a technique that in certain circumstances allows one to avoid the removal of dynamic shadows in the visible spectrum making use of images in the infrared spectrum. This technique emerged from a real problem concerning the autonomous navigation of a vehicle in a wind farm. In this environment, the dynamic shadows cast by the wind turbines’ blades make it necessary to include a shadows removal stage in the preprocessing of the visible spectrum images in order to avoid the shadows being misclassified as obstacles. In the thermal images, dynamic shadows completely disappear, something that does not always occur in the visible spectrum, even when the preprocessing is executed. Thus, a fusion on thermal and visible bands is performed.

  13. Shadowing Observations of the Galactic Halo with XMM-Newton and Suzaku

    Science.gov (United States)

    Shelton, Robin

    analysis of the sample of shadowing clouds observed with XMM and/or Suzaku. We will use these shadows to measure the halo X-ray emission. Our proposed analysis will improve upon previous shadowing studies in a number of ways: 1) Our sample includes two new targets in the northern Galactic hemisphere, for which there are no previous XMM or Suzaku shadowing observations. 2) Â We will use a SWCX model to model the foreground emission in our spectra. This should result in a more accurate characterization of the foreground emission than did the previously used thermal plasma models. 3) Â Our sample includes a previously unobserved compact cloud that offers the opportunity to extract the on- and off-shadow spectra from a single XMM field of view, ensuring that the foreground SWCX emission is identical in both spectra. Such an observation has not been attempted with a CCD-resolution spectrometer. 4) Â For targets with separate on- and off-shadow pointings (i.e. all but one), we will, for the first time, investigate the systematic errors associated with assuming that the foreground emission does not change between the two pointings. 5) Â We will use a Markov Chain Monte Carlo method to map out the temperature- emission measure confidence regions for the halo. 6) Â As well as reporting the observational results, we will compare these results with the predictions of hydrodynamic models of the halo, in order to determine the relative contributions of outflow and infall to the hot halo gas, and to search for evidence of important processes not included in the models. By using these shadowing observations to study the physical conditions in and the origin and evolution of the hot Galactic halo, we will contribute toward NASA's Astrophysics Science Goals of understanding how matter and energy behave under the extraordinarily diverse conditions of the cosmos, and understanding the phenomena and processes associated with galaxy formation and evolution.

  14. WAVS radiation shielding references and assumptions

    Energy Technology Data Exchange (ETDEWEB)

    McLean, Adam [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-10-07

    At ITER, the confluence of a high radiation environment and the requirement for high performance imaging for plasma and plasma-facing surface diagnosis will necessitate extensive application of radiation shielding. Recommended here is a dual-layer shield design composed of lead for gamma attenuation, surrounded by a fire-resistant polyehtylene doped with a thermal neutron absorber for neutron shielding.

  15. Geomechanical effects of stress shadow created by large-scale destress blasting

    Directory of Open Access Journals (Sweden)

    Isaac Vennes

    2017-12-01

    Full Text Available This study aims to determine if large-scale choked panel destress blasting can provide sufficient beneficial stress reduction in highly-stressed remnant ore pillar that is planned for production. The orebody is divided into 20 stopes over 2 levels, and 2 panels are choke-blasted in the hanging wall to shield the ore pillar by creating a stress shadow around it. A linear-elastic model of the mining system is constructed with finite difference code FLAC3D. The effect of destress blasting in the panels is simulated by applying a fragmentation factor (α to the rock mass stiffness and a stress reduction factor (β to the current state of stress in the region occupied by the destress panels. As an extreme case, the destress panel is also modeled as a void to obtain the maximum possible beneficial effects of destressing and stress shadow. Four stopes are mined in the stress shadow of the panels in 6 lifts and then backfilled. The effect of destress blasting on the remnant ore pillar is quantified based on stress change and brittle shear ratio (BSR in the stress shadow zone compared to the base case without destress blasting. To establish realistic rock fragmentation and stress reduction factors, model results are compared to measured stress changes reported for case studies at Fraser and Brunswick mines. A 1.5 MPa immediate stress decrease was observed 20 m away from the panel at Fraser Mine, and a 4 MPa immediate stress decrease was observed 25 m away at Brunswick Mine. Comparable results are obtained from the current model with a rock fragmentation factor α of 0.2 and a stress reduction factor β of 0.8. It is shown that a destress blasting with these parameters reduces the major principal stress in the nearest stopes by 10–25 MPa. This yields an immediate reduction of BSR, which is deemed sufficient to reduce volume of ore at risk in the pillar.

  16. Experimental Evaluation of a Water Shield for a Surface Power Reactor

    Science.gov (United States)

    Pearson, J. Boise; Reid, Robert S.

    2006-01-01

    As part of the Vision for Space Exploration the end of the next decade will bring man back to the surface of the moon. One of the most critical issues for the establishment of human presence on the moon will be the availability of compact power sources. The establishment of man on the moon will require power from greater than 10's of kWt's in follow on years. Nuclear reactors are extremely we11 suited to meet the needs for power generation on the lunar or Martian surface. reactor system. Several competing concepts exist for lightweight, safe, robust shielding systems such as a water shield, lithium hydride (LiH), Boron Carbide, and others. Water offers several potential advantages, including reduced cost, reduced technical risk, and reduced mass. Water has not typically been considered for space reactor applications because of the need for gravity to remove the potential for radiation streaming paths. The water shield concept relies on predictions of passive circulation of the shield water by natural convection to adequately cool the shield. This prediction needs to be experimentally evaluated, especially for shields with complex geometries. MSFC has developed the experience and fac necessary to do this evaluation in the Early Flight Fission - Test Facility (EFF-TF).

  17. Small Valdivia compact spaces

    CERN Document Server

    Kubi's, W; Kubi\\'s, Wieslaw; Michalewski, Henryk

    2005-01-01

    We prove a preservation theorem for the class of Valdivia compact spaces, which involves inverse sequences of ``simple'' retractions. Consequently, a compact space of weight $\\loe\\aleph_1$ is Valdivia compact iff it is the limit of an inverse sequence of metric compacta whose bonding maps are retractions. As a corollary, we show that the class of Valdivia compacta of weight at most $\\aleph_1$ is preserved both under retractions and under open 0-dimensional images. Finally, we characterize the class of all Valdivia compacta in the language of category theory, which implies that this class is preserved under all continuous weight preserving functors.

  18. Compact boson stars

    Energy Technology Data Exchange (ETDEWEB)

    Hartmann, Betti [School of Engineering and Science, Jacobs University, Postfach 750 561, D-28725 Bremen (Germany); Kleihaus, Burkhard; Kunz, Jutta [Institut fuer Physik, Universitaet Oldenburg, Postfach 2503, D-26111 Oldenburg (Germany); Schaffer, Isabell, E-mail: i.schaffer@jacobs-university.de [School of Engineering and Science, Jacobs University, Postfach 750 561, D-28725 Bremen (Germany)

    2012-07-24

    We consider compact boson stars that arise for a V-shaped scalar field potential. They represent a one parameter family of solutions of the scaled Einstein-Gordon equations. We analyze the physical properties of these solutions and determine their domain of existence. Along their physically relevant branch emerging from the compact Q-ball solution, their mass increases with increasing radius. Employing arguments from catastrophe theory we argue that this branch is stable, until the maximal value of the mass is reached. There the mass and size are on the order of magnitude of the Schwarzschild limit, and thus the spiraling respectively oscillating behaviour, well known for compact stars, sets in.

  19. Neutronic design of MYRRHA reactor hall shielding

    Science.gov (United States)

    Celik, Yurdunaz; Stankovskiy, Alexey; Eynde, Gert Van den

    2017-09-01

    The lateral shielding of a 600 MeV proton linear accelerator beam line in the MYRRHA reactor hall has been assessed using neutronic calculations by the MCNPX code complemented with analytical predictions. Continuous beam losses were considered to define the required shielding thickness that meets the requirements for the dose rate limits. Required shielding thicknesses were investigated from the viewpoint of accidental full beam loss as well as beam loss on collimator. The results confirm that the required shielding thicknesses are highly sensitive to the spatial shape of the beam and strongly divergent beam losses. Therefore shielding barrier should be designed according to the more conservative assumptions.

  20. A shadow detector for photosynthesis efficiency.

    Science.gov (United States)

    Liao, Kang-Ling; Jones, Roger D; McCarter, Patrick; Tunc-Ozdemir, Meral; Draper, James A; Elston, Timothy C; Kramer, David; Jones, Alan M

    2017-02-07

    Plants tolerate large variations in the intensity of the light environment by controlling the efficiency of solar to chemical energy conversion. To do this, plants have a mechanism to detect the intensity, duration, and change in light as they experience moving shadows, flickering light, and cloud cover. Sugars are the primary products of CO2 fixation, a metabolic pathway that is rate limited by this solar energy conversion. We propose that sugar is a signal encoding information about the intensity, duration and change in the light environment. We previously showed that the Arabidopsis heterotrimeric G protein complex including its receptor-like Regulator of G signaling protein, AtRGS1, detects both the concentration and the exposure time of sugars (Fu et al., 2014. Cell 156: 1084-1095). This unique property, designated dose-duration reciprocity, is a behavior that emerges from the system architecture / system motif. Here, we show that another property of the signaling system is to detect large changes in light while at the same time, filtering types of fluctuation in light that do not affect photosynthesis efficiency. When AtRGS1 is genetically ablated, photosynthesis efficiency is reduced in a changing- but not a constant-light environment. Mathematical modeling revealed that information about changes in the light environment is encoded in the amount of free AtRGS1 that becomes compartmentalized following stimulation. We propose that this property determines when to adjust photosynthetic efficiency in an environment where light intensity changes abruptly caused by moving shadows on top of a background of light changing gradually from sun rise to sun set and fluctuating light such as that caused by fluttering leaves. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Automatic and Accurate Shadow Detection Using Near-Infrared Information.

    Science.gov (United States)

    Rüfenacht, Dominic; Fredembach, Clément; Süsstrunk, Sabine

    2014-08-01

    We present a method to automatically detect shadows in a fast and accurate manner by taking advantage of the inherent sensitivity of digital camera sensors to the near-infrared (NIR) part of the spectrum. Dark objects, which confound many shadow detection algorithms, often have much higher reflectance in the NIR. We can thus build an accurate shadow candidate map based on image pixels that are dark both in the visible and NIR representations. We further refine the shadow map by incorporating ratios of the visible to the NIR image, based on the observation that commonly encountered light sources have very distinct spectra in the NIR band. The results are validated on a new database, which contains visible/NIR images for a large variety of real-world shadow creating illuminant conditions, as well as manually labeled shadow ground truth. Both quantitative and qualitative evaluations show that our method outperforms current state-of-the-art shadow detection algorithms in terms of accuracy and computational efficiency.

  2. Making Graphical Information Visible in Real Shadows on Interactive Tabletops.

    Science.gov (United States)

    Isogawa, Mariko; Iwai, Daisuke; Sato, Kosuke

    2014-09-01

    We introduce a shadow-based interface for interactive tabletops. The proposed interface allows a user to browse graphical information by casting the shadow of his/her body, such as a hand, on a tabletop surface. Central to our technique is a new optical design that utilizes polarization in addition to the additive nature of light so that the desired graphical information is displayed only in a shadow area on a tabletop surface. In other words, our technique conceals the graphical information on surfaces other than the shadow area, such as the surface of the occluder and non-shadow areas on the tabletop surface. We combine the proposed shadow-based interface with a multi-touch detection technique to realize a novel interaction technique for interactive tabletops. We implemented a prototype system and conducted proof-of-concept experiments along with a quantitative evaluation to assess the feasibility of the proposed optical design. Finally, we showed implemented application systems of the proposed shadow-based interface.

  3. ATLAS Award for Shield Supplier

    CERN Multimedia

    2004-01-01

    ATLAS technical coordinator Dr. Marzio Nessi presents the ATLAS supplier award to Vojtech Novotny, Director General of Skoda Hute.On 3 November, the ATLAS experiment honoured one of its suppliers, Skoda Hute s.r.o., of Plzen, Czech Republic, for their work on the detector's forward shielding elements. These huge and very massive cylinders surround the beampipe at either end of the detector to block stray particles from interfering with the ATLAS's muon chambers. For the shields, Skoda Hute produced 10 cast iron pieces with a total weight of 780 tonnes at a cost of 1.4 million CHF. Although there are many iron foundries in the CERN member states, there are only a limited number that can produce castings of the necessary size: the large pieces range in weight from 59 to 89 tonnes and are up to 1.5 metres thick.The forward shielding was designed by the ATLAS Technical Coordination in close collaboration with the ATLAS groups from the Czech Technical University and Charles University in Prague. The Czech groups a...

  4. Detecting the structural form of cast shadows patterns.

    Science.gov (United States)

    Khuu, Sieu K; Khambiye, Shazaan; Phu, Jack

    2012-10-17

    Cast shadows are ubiquitous in the visual scene and they inform greatly about the scene's three-dimensional spatial layout. In the present study we investigated the ability of the visual system to detect the structural form of cast shadows using Glass patterns consisting of local dot-pairs or dipoles oriented appropriately to convey global structure. "Cast shadow" Glass patterns were constructed by superimposing two opposite polarity (light-increment - the object - and light-decrement - the shadow) concentric Glass patterns and then spatially displacing the decrement pattern along a particular orientation conforming to the pattern's lighting direction. We determined the shadow detection threshold, which specifies the amount of structural difference between the object (increment Glass-pattern) and its respective shadow (decrement Glass-pattern), required for observers to detect the cast shadow. This was achieved by varying the ratio between local opposite-polarity dipole pairs that were appropriately aligned along the lighting direction (congruent dipole pairs), and dipole pairs that were randomly oriented (incongruent dipole pairs), and were therefore inconsistent with the pattern's lighting direction. We reported that thresholds were comparatively lower (i.e., the visual system is able to tolerate greater local pattern inconsistencies) for light-from-above patterns than for light-from-below patterns (Experiment 1), and detection is optimal for highly coherent patterns (Experiment 2) small spatial separations between opposite polarity (Experiment 3). Our findings demonstrated that the visual system is more sensitive to light-from-above configurations when detecting the form of cast shadows, and this detection process largely ignores local inconsistencies between the object and its respective shadow.

  5. Compost Compaction Evaluation.

    Science.gov (United States)

    1993-10-01

    aerated static pile composting ) has been shown to be most effective at reducing the explosives levels in the soils (4). As a result, it is anticipated...y ■,... tiiii silsis H-ifjfe Compost Compaction Evaluation Report No. ENAEC-TS-CR-93110 Contract No. DACA31-9-D-0079 Task Order No. 01...Leave blank) 2. REPORT DATE October 1993 3. REPORT TYPE AND DATES COVERED Final Report 4. TITLE AND SUBTITLE Compost Compaction Evaluation 6

  6. Black Hole Shadows of Charged Spinning Black Holes

    OpenAIRE

    Takahashi, Rohta

    2005-01-01

    We propose a method for measuring the black hole charge by imaging a black hole shadow in a galactic center by future interferometers. Even when the black hole is uncharged, it is possible to confirm the charge neutrality by this method. We first derive the analytic formulae of the black hole shadow in an optically thin medium around a charged spinning black hole, and then investigate how contours of the black hole shadow depend on the spin and the charge of the black hole for several inclina...

  7. A locally adaptive algorithm for shadow correction in color images

    Science.gov (United States)

    Karnaukhov, Victor; Kober, Vitaly

    2017-09-01

    The paper deals with correction of color images distorted by spatially nonuniform illumination. A serious distortion occurs in real conditions when a part of the scene containing 3D objects close to a directed light source is illuminated much brighter than the rest of the scene. A locally-adaptive algorithm for correction of shadow regions in color images is proposed. The algorithm consists of segmentation of shadow areas with rank-order statistics followed by correction of nonuniform illumination with human visual perception approach. The performance of the proposed algorithm is compared to that of common algorithms for correction of color images containing shadow regions.

  8. More Efficient Virtual Shadow Maps for Many Lights.

    Science.gov (United States)

    Olsson, Ola; Billeter, Markus; Sintorn, Erik; Kampe, Viktor; Assarsson, Ulf

    2015-06-01

    Recently, several algorithms have been introduced that enable real-time performance for many lights in applications such as games. In this paper, we explore the use of hardware-supported virtual cube-map shadows to efficiently implement high-quality shadows from hundreds of light sources in real time and within a bounded memory footprint. In addition, we explore the utility of ray tracing for shadows from many lights and present a hybrid algorithm combining ray tracing with cube maps to exploit their respective strengths. Our solution supports real-time performance with hundreds of lights in fully dynamic high-detail scenes.

  9. Transmit antenna selection based on shadowing side information

    KAUST Repository

    Yilmaz, Ferkan

    2011-05-01

    In this paper, we propose a new transmit antenna selection scheme based on shadowing side information. In the proposed scheme, single transmit antenna which has the highest shadowing coefficient is selected. By the proposed technique, usage of the feedback channel and channel estimation complexity at the receiver can be reduced. We consider independent but not identically distributed Generalized-K composite fading model, which is a general composite fading & shadowing channel model for wireless environments. Exact closed-form outage probability, moment generating function and symbol error probability expressions are derived. In addition, theoretical performance results are validated by Monte Carlo simulations. © 2011 IEEE.

  10. Protective Effectiveness of Porous Shields Under the Influence of High-Speed Impact Loading

    Directory of Open Access Journals (Sweden)

    Kramshonkov E.N.

    2016-01-01

    Full Text Available The results of numerical simulations of a compact steel impactor with the aluminum porous shields under high-speed shock loading are presented. The porosity of barrier varies in wide range provided that its mass stays the same, but the impactor has always equal (identical mass. Here presented the final assessment of the barrier perforation speed depending on its porosity and initial shock speed. The range of initial impact speed varies from 1 to 10 km/s. Physical phenomena such as: destruction, melting, vaporization of a interacting objects are taken into account. The analysis of a shield porosity estimation disclosed that the protection effectiveness of porous shield reveals at the initial impact speed grater then 1.5 km/s, and it increases when initial impact speed growth.

  11. Shadows Constructing a Relationship between Light and Color Pigments by Physical and Mathematical Perspectives

    Science.gov (United States)

    Yurumezoglu, Kemal; Karabey, Burak; Koyunkaya, Melike Yigit

    2017-01-01

    Full shadows, partial shadows and multilayer shadows are explained based on the phenomenon of the linear dispersion of light. This paper focuses on progressing the understanding of shadows from physical and mathematical perspectives. A significant relationship between light and color pigments is demonstrated with the help of the concept of sets.…

  12. Compaction of FGD-gypsum

    NARCIS (Netherlands)

    Stoop, B.T.J.; Larbi, J.A.; Heijnen, W.M.M.

    1996-01-01

    It is shown that it is possible to produce compacted gypsum with a low porosity and a high strength on a laboratory scale by uniaxial compaction of flue gas desulphurization (FGD-) gypsum powder. Compacted FGD-gypsum cylinders were produced at a compaction pres-sure between 50 and 500 MPa yielding

  13. Shadow banking in China: expanding scale, evolving structure

    OpenAIRE

    Li, Cindy

    2013-01-01

    This Asia Focus provides an overview of shadow banking activities in China, their close ties with banks, reasons behind their rapid rise, the range of participants and products, and regulatory issues.

  14. Overestimation of Mach number due to probe shadow

    Science.gov (United States)

    Gosselin, J. J.; Thakur, S. C.; Sears, S. H.; McKee, J. S.; Scime, E. E.; Tynan, G. R.

    2016-07-01

    Comparisons of the plasma ion flow speed measurements from Mach probes and laser induced fluorescence were performed in the Controlled Shear Decorrelation Experiment. We show the presence of the probe causes a low density geometric shadow downstream of the probe that affects the current density collected by the probe in collisional plasmas if the ion-neutral mean free path is shorter than the probe shadow length, Lg = w2 Vdrift/D⊥, resulting in erroneous Mach numbers. We then present a simple correction term that provides the corrected Mach number from probe data when the sound speed, ion-neutral mean free path, and perpendicular diffusion coefficient of the plasma are known. The probe shadow effect must be taken into account whenever the ion-neutral mean free path is on the order of the probe shadow length in linear devices and the open-field line region of fusion devices.

  15. Testing General Relativity with the Shadow Size of Sgr A(*).

    Science.gov (United States)

    Johannsen, Tim; Broderick, Avery E; Plewa, Philipp M; Chatzopoulos, Sotiris; Doeleman, Sheperd S; Eisenhauer, Frank; Fish, Vincent L; Genzel, Reinhard; Gerhard, Ortwin; Johnson, Michael D

    2016-01-22

    In general relativity, the angular radius of the shadow of a black hole is primarily determined by its mass-to-distance ratio and depends only weakly on its spin and inclination. If general relativity is violated, however, the shadow size may also depend strongly on parametric deviations from the Kerr metric. Based on a reconstructed image of Sagittarius A^{*} (Sgr A^{*}) from a simulated one-day observing run of a seven-station Event Horizon Telescope (EHT) array, we employ a Markov chain Monte Carlo algorithm to demonstrate that such an observation can measure the angular radius of the shadow of Sgr A^{*} with an uncertainty of ∼1.5  μas (6%). We show that existing mass and distance measurements can be improved significantly when combined with upcoming EHT measurements of the shadow size and that tight constraints on potential deviations from the Kerr metric can be obtained.

  16. A historical note on illusory contours in shadow writing.

    Science.gov (United States)

    Vezzani, Stefano; Marino, Barbara F M

    2009-01-01

    It is widely accepted that illusory contours have been first displayed and discussed by Schumann (1900, Zeitschrift für Psychologie und Physiologie der Sinnesorgane 23 1-32). Here we show that, before him, Jastrow (1899, Popular Science Monthly 54 299-312) produced illusory contours consisting of a shadow word. A brief history of shadow writing in psychological literature from Jastrow to Brunswik is presented, in which the contributions of Pillsbury, Warren, Koffka, and Benussi are examined.

  17. Nuclear shadowing and the optics of hadronic fluctuations

    Energy Technology Data Exchange (ETDEWEB)

    Mankiewicz, L. E-mail: lech_mankiewicz@camk.edu.pl; Piller, G.; Vaenttinen, M.; Weise, W

    2001-06-04

    A coordinate-space description of shadowing in deep-inelastic lepton-nucleus scattering is presented. The picture in the laboratory frame is that of quark-gluon fluctuations of the high-energy virtual photon, propagating coherently over large light-cone distances in the nuclear medium. We discuss the detailed dependence of the coherence effects on the invariant mass of the fluctuation. We comment on the issue of possible saturation in the shadowing effects at very small Bjorken-x.

  18. Physician shadowing by college students: what do patients think?

    OpenAIRE

    Bing-You, Robert G; Hayes, Victoria M; Skolfield, Jennifer L

    2014-01-01

    Background The objective of this study is to determine patients’ perceptions of physician shadowing by college students. Methods Thirty-two patients who agreed to have a college student shadow their physician participated in semi-structured interviews during July and August 2013 at two outpatient family medicine centers. Qualitative techniques were utilized to analyze the transcripts of the patient interviews and identify common themes. Results The majority of patients (78.1%) felt the colleg...

  19. Spacecraft's Attitude Prediction: Solar Radiation Torque and the Earth's Shadow

    Science.gov (United States)

    Zanardi, M. C.; Vilhena de Moraes, R.; Cabette, R. S.; Garcia, R. V.

    A semi-analytical approach is proposed to study the rotational motion of a spacecraft under the influence of the solar radiation torque and taking into account the influence of the Earth's shadow. The equations of motion are given in an Hamiltonian formalism and Andoyer variables are used to describe the spacecraft rotational motion. The model for the shadow function was developed by Kabelac which considers geometric and physical factors and three specific regions: shadow, penumbra and total illuminated. Special attention is focused on the influence of the orbital elements and the positioning of the Sun in the duration of the Earth's shadow and penumbra. By mapping and computing the shadow function it is possible to get the periods in which the spacecraft is illuminated and when it is in the umbra (in this case the solar radiation torque is zero). The semi-analytical process is applied to get the solution for the equations of motion, using the mapping of the shadow function. When the satellite is illuminated or it is in the penumbra, a known analytical solution is used to predict the spacecraft's attitude. Numerical simulations are presented considering different sets of orbital characteristics for the satellite and positioning of the Sun in the Ecliptic. By numerical results it is possible to observe important influence of the orbital elements on the time for crossing penumbra and shadow regions. Numerical simulations show also that the transition from the shadow region to the illumined region was attenuated when of the penumbra region is included in the dynamical problem.

  20. Introducing Adaptive Filters Based on Shadow Concept for Speech Processing

    OpenAIRE

    Koteswara Rao, M; Prabha, I.Santhi

    2014-01-01

    This paper presents the new approach to introducing adaptive Filter with LMS Algorithm based on Shadow concept. Which is useful for the cancellation of the noise component overlap with Speech signal in the same frequency range, but fixed LMS algorithm produces minimum convergence rate and fixed steady state error. So we presents design, implementation and performance of adaptive FIR filter, based on Shadow concept, which produces minimum mean square error compare to fixed LMS, and we also o...

  1. Ferromagnetic shadow mask for spray coating of polymer patterns

    DEFF Research Database (Denmark)

    Keller, Stephan Sylvest; Bosco, Filippo; Boisen, Anja

    2013-01-01

    We present the fabrication of a wafer-scale shadow mask with arrays of circular holes with diameters of 150–400 μm. Standard UV photolithography is used to define 700 μm thick SU-8 structures followed by electroplating of nickel and etching of the template. The ferromagnetic properties of the sha...... of the shadow mask allow magnetic clamping to the substrate and spray coating of well defined polymer patterns....

  2. Terrestrial hyperspectral image shadow restoration through fusion with terrestrial lidar

    Science.gov (United States)

    Hartzell, Preston J.; Glennie, Craig L.; Finnegan, David C.; Hauser, Darren L.

    2017-05-01

    Recent advances in remote sensing technology have expanded the acquisition and fusion of active lidar and passive hyperspectral imagery (HSI) from exclusively airborne observations to include terrestrial modalities. In contrast to airborne collection geometry, hyperspectral imagery captured from terrestrial cameras is prone to extensive solar shadowing on vertical surfaces leading to reductions in pixel classification accuracies or outright removal of shadowed areas from subsequent analysis tasks. We demonstrate the use of lidar spatial information for sub-pixel HSI shadow detection and the restoration of shadowed pixel spectra via empirical methods that utilize sunlit and shadowed pixels of similar material composition. We examine the effectiveness of radiometrically calibrated lidar intensity in identifying these similar materials in sun and shade conditions and further evaluate a restoration technique that leverages ratios derived from the overlapping lidar laser and HSI wavelengths. Simulations of multiple lidar wavelengths, i.e., multispectral lidar, indicate the potential for HSI spectral restoration that is independent of the complexity and costs associated with rigorous radiometric transfer models, which have yet to be developed for horizontal-viewing terrestrial HSI sensors. The spectral restoration performance of shadowed HSI pixels is quantified for imagery of a geologic outcrop through improvements in spectral shape, spectral scale, and HSI band correlation.

  3. The multisensory body revealed through its cast shadows

    Directory of Open Access Journals (Sweden)

    Francesco ePavani

    2015-05-01

    Full Text Available One key issue when conceiving the body as a multisensory object is how the cognitive system integrates visible instances of the self and other bodies with one’s own somatosensory processing, to achieve self-recognition and body ownership. Recent research has strongly suggested that shadows cast by our own body have a special status for cognitive processing, directing attention to the body in a fast and highly specific manner. The aim of the present article is to review the most recent scientific contributions addressing how body shadows affect both sensory/perceptual and attentional processes. The review examines three main points: (1 body shadows as a special window to investigate the construction of multisensory body perception; (2 experimental paradigms and related findings; (3 open questions and future trajectories. The reviewed literature suggests that shadows cast by one’s own body promote binding between personal and extrapersonal space and elicit automatic orienting of attention toward the body-part casting the shadow. Future research should address whether the effects exerted by body shadows are similar to those observed when observers are exposed to other visual instances of their body. The results will further clarify the processes underlying the merging of vision and somatosensation when creating body representations.

  4. Dynamic rotating-shield brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yunlong [Department of Electrical and Computer Engineering, University of Iowa, 4016 Seamans Center, Iowa City, Iowa 52242 (United States); Flynn, Ryan T.; Kim, Yusung [Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242 (United States); Yang, Wenjun [Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, Wisconsin 53705 (United States); Wu, Xiaodong [Department of Electrical and Computer Engineering, University of Iowa, 4016 Seamans Center, Iowa City, Iowa 52242 and Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242 (United States)

    2013-12-15

    Purpose: To present dynamic rotating shield brachytherapy (D-RSBT), a novel form of high-dose-rate brachytherapy (HDR-BT) with electronic brachytherapy source, where the radiation shield is capable of changing emission angles during the radiation delivery process.Methods: A D-RSBT system uses two layers of independently rotating tungsten alloy shields, each with a 180° azimuthal emission angle. The D-RSBT planning is separated into two stages: anchor plan optimization and optimal sequencing. In the anchor plan optimization, anchor plans are generated by maximizing the D{sub 90} for the high-risk clinical-tumor-volume (HR-CTV) assuming a fixed azimuthal emission angle of 11.25°. In the optimal sequencing, treatment plans that most closely approximate the anchor plans under the delivery-time constraint will be efficiently computed. Treatment plans for five cervical cancer patients were generated for D-RSBT, single-shield RSBT (S-RSBT), and {sup 192}Ir-based intracavitary brachytherapy with supplementary interstitial brachytherapy (IS + ICBT) assuming five treatment fractions. External beam radiotherapy doses of 45 Gy in 25 fractions of 1.8 Gy each were accounted for. The high-risk clinical target volume (HR-CTV) doses were escalated such that the D{sub 2cc} of the rectum, sigmoid colon, or bladder reached its tolerance equivalent dose in 2 Gy fractions (EQD2 with α/β= 3 Gy) of 75 Gy, 75 Gy, or 90 Gy, respectively.Results: For the patients considered, IS + ICBT had an average total dwell time of 5.7 minutes/fraction (min/fx) assuming a 10 Ci{sup 192}Ir source, and the average HR-CTV D{sub 90} was 78.9 Gy. In order to match the HR-CTV D{sub 90} of IS + ICBT, D-RSBT required an average of 10.1 min/fx more delivery time, and S-RSBT required 6.7 min/fx more. If an additional 20 min/fx of delivery time is allowed beyond that of the IS + ICBT case, D-RSBT and S-RSBT increased the HR-CTV D{sub 90} above IS + ICBT by an average of 16.3 Gy and 9.1 Gy, respectively

  5. Light - Shadow Interactions in Italian Medieval Churches

    Science.gov (United States)

    Incerti, Manuela

    In the relationship between architecture and the sky, it is possible to identify three different design issues. The first regards the alignment of buildings with visible points on the horizon that coincide with the rising or setting of a celestial body (sun, planets, stars, or moon) on particular dates during the astronomical year (or liturgical year for sacred buildings). The second is the relationship between planimetric design and the design of the elevations. We are all familiar today with several "light effects", which sometimes have almost hierophanic characteristics that, on certain days of the year, were used to engross, captivate, and amaze the spectator. Contrary to the first two issues, the third comes after the design and building stages and concerns the question of decorative elements. It is reasonable to believe that many years after the works were terminated, certain wall finishings were chosen over others, such as painted frescoes or statues. Whoever did this was fully aware, thanks to direct observation, that such decoration would be struck by a single ray of light on a specific day. This chapter examines light-shadow interactions in some Italian medieval churches.

  6. Smartphone based Tomographic PIV using colored shadows

    Science.gov (United States)

    Aguirre-Pablo, Andres A.; Alarfaj, Meshal K.; Li, Er Qiang; Thoroddsen, Sigurdur T.

    2016-11-01

    We use low-cost smartphones and Tomo-PIV, to reconstruct the 3D-3C velocity field of a vortex ring. The experiment is carried out in an octagonal tank of water with a vortex ring generator consisting of a flexible membrane enclosed by a cylindrical chamber. This chamber is pre-seeded with black polyethylene microparticles. The membrane is driven by an adjustable impulsive air-pressure to produce the vortex ring. Four synchronized smartphone cameras, of 40 Mpx each, are used to capture the location of particles from different viewing angles. We use red, green and blue LED's as backlighting sources, to capture particle locations at different times. The exposure time on the smartphone cameras are set to 2 seconds, while exposing each LED color for about 80 μs with different time steps that can go below 300 μs. The timing of these light pulses is controlled with a digital delay generator. The backlight is blocked by the instantaneous location of the particles in motion, leaving a shadow of the corresponding color for each time step. The image then is preprocessed to separate the 3 different color fields, before using the MART reconstruction and cross-correlation of the time steps to obtain the 3D-3C velocity field. This proof of concept experiment represents a possible low-cost Tomo-PIV setup.

  7. Celestial shadows eclipses, transits, and occultations

    CERN Document Server

    Westfall, John

    2015-01-01

    Much of what is known about the universe comes from the study of celestial shadows—eclipses, transits, and occultations.  The most dramatic are total eclipses of the Sun, which constitute one of the most dramatic and awe-inspiring events of nature.  Though once a source of consternation or dread, solar eclipses now lead thousands of amateur astronomers and eclipse-chasers to travel to remote points on the globe to savor their beauty and the adrenaline-rush of experiencing totality, and were long the only source of information about the hauntingly beautiful chromosphere and corona of the Sun.   Long before Columbus, the curved shadow of the Earth on the Moon during a lunar eclipse revealed that we inhabit a round world. The rare and wonderful transits of Venus, which occur as it passes between the Earth and the Sun, inspired eighteenth century expeditions to measure the distance from the Earth to the Sun, while the recent transits of 2004 and 2012 were the most widely observed ever--and still produced re...

  8. Radiation shielding concrete made of Basalt aggregates.

    Science.gov (United States)

    Alhajali, S; Yousef, S; Kanbour, M; Naoum, B

    2013-04-01

    In spite of the fact that Basalt is a widespread type of rock, there is very little available information on using it as aggregates for concrete radiation shielding. This paper investigates the possibility of using Basalt for the aforementioned purpose. The results have shown that Basalt could be used successfully for preparing radiation shielding concrete, but some attention should be paid to the choice of the suitable types of Basalt and for the neutron activation problem that could arise in the concrete shield.

  9. Radiation shielding analysis for 50 kVp x-ray intra-operative radiotherapy (IORT) device using MCNPX code

    Energy Technology Data Exchange (ETDEWEB)

    Wang Zhao Jun; Yeom, Yeon Soo; Kim, Chan Hyeong [Hanyang University, Seoul (Korea, Republic of)

    2014-04-15

    The present study performed Monte Carlo simulations for the 50 kVp X-ray intra-operative radiotherapy (IORT) device for detailed radiation shielding analysis. The INTRABEAM system (Carl Zeiss Surgical, Oberkochen, Germany) is a compact 50 kVp X-ray device used for intra-operative radiotherapy (IORT) especially for breast cancer. The IORT system has the advantages of very rapid dose gradient and, due to the on/off switching system, no risk of contamination when compared to nuclear medicine procedure. In contrast to megavoltage radiotherapy system requiring a dedicated shielding bunker, the IORT system is generally performed in standard operating theatres and simply uses a thin shield on the treated area and lead screens for protection of staffs who stay in the theatre during treatment. For detailed radiation shielding analysis of the IORT system, the present study performed Monte Carlo simulations with the MCNPX code to calculate dose rate distributions and investigated effects of several shielding components generally considered in this system. It was shown that shielding with flat cover and lead screen generally used is sufficient to reduce occupational doses to a negligible level. The analysis results of this study can be referred to estimate shielding requirements for other IORT systems.

  10. Compaction of poultry litter.

    Science.gov (United States)

    Bernhart, M; Fasina, O O; Fulton, J; Wood, C W

    2010-01-01

    Poultry litter, a combination of accumulated chicken manure, feathers and bedding materials, is a potential feedstock for bioenergy and other value-added applications. The use of this waste product has been historically limited to within few miles of the place of generation because of its inherent low density. Compaction is one possible way to enhance the storage and transportation of the litter. This study therefore investigates the effect of moisture content (19.8-70.7%, d.b.) and pressure (0.8-8.4 MPa) on the compaction characteristics of poultry litter. Results obtained showed that the initial density of densified poultry litter, energy required for compaction and the strength of the densified material after 2 months of storage were significantly (Ppoultry litter.

  11. Design and analysis of electromagnetic interference filters and shields

    Science.gov (United States)

    McDowell, Andrew Joel

    Electromagnetic interference (EMI) is a problem of rising prevalence as electronic devices become increasingly ubiquitous. EMI filters are low pass filters intended to prevent the conducted electric currents and radiated electromagnetic fields of a device from interfering with the proper operation of other devices. Shielding is a method, often complementary to filtering, that typically involves enclosing a device in a conducting box in order to prevent radiated EMI. This dissertation includes three chapters related to the use of filtering and shielding for preventing electromagnetic interference. The first chapter deals with improving the high frequency EMI filtering performance of surface mount capacitors on printed circuit boards (PCBs). At high frequencies, the impedance of a capacitor is dominated by a parasitic inductance, thus leading to poor high frequency filtering performance. Other researchers have introduced the concept of parasitic inductance cancellation and have applied this concept to improving the filtering performance of volumetrically large capacitors at frequencies up to 100 MHz. The work in this chapter applies the concept of parasitic inductance cancellation to much smaller surface mount capacitors at frequencies up to several gigahertz. The second chapter introduces a much more compact design for applying parasitic inductance cancellation to surface mount capacitors that uses inductive coupling between via pairs as well as coplanar traces. This new design is suited for PCBs having three or more layers including solid ground and/or power plane(s). This design is demonstrated to be considerably more effective in filtering high frequency noise due to crosstalk than a comparable conventional shunt capacitor filter configuration. Finally, chapter 3 presents a detailed analysis of the methods that are used to decompose the measure of plane wave shielding effectiveness into measures of absorption and reflection. Textbooks on electromagnetic

  12. The ORNL-SNAP shielding program

    Science.gov (United States)

    Mynatt, F. R.; Clifford, C. E.; Muckenthaler, F. J.; Gritzner, M. L.

    1972-01-01

    The effort in the ORNL-SNAP shielding program is directed toward the development and verification of computer codes using numerical solutions to the transport equation for the design of optimized radiation shields for SNAP power systems. A brief discussion is given for the major areas of the SNAP shielding program, which are cross-section development, transport code development, and integral experiments. Detailed results are presented for the integral experiments utilizing the TSF-SNAP reactor. Calculated results are compared with experiments for neutron and gamma-ray spectra from the bare reactor and as transmitted through slab shields.

  13. NEUTRONIC REACTOR SHIELD AND SPACER CONSTRUCTION

    Science.gov (United States)

    Wigner, E.P.; Ohlinger, L.A.

    1958-11-18

    Reactors of the heterogeneous, graphite moderated, fluid cooled type and shielding and spacing plugs for the coolant channels thereof are reported. In this design, the coolant passages extend horizontally through the moderator structure, accommodating the fuel elements in abutting end-to-end relationship, and have access openings through the outer shield at one face of the reactor to facilitate loading of the fuel elements. In the outer ends of the channels which extend through the shields are provided spacers and shielding plugs designed to offer minimal reslstance to coolant fluid flow while preventing emanation of harmful radiation through the access openings when closed between loadings.

  14. Continuous electrodeionization through electrostatic shielding

    Energy Technology Data Exchange (ETDEWEB)

    Dermentzis, Konstantinos [Technological Educational Institute, T.E.I. of Kavala, General Department of Sciences, Laboratory of Chemical Technology, Agios Loucas, 65404 Kavala (Greece)], E-mail: demerz@otenet.gr

    2008-02-15

    We report a new continuous electrodeionization cell with electrostatically shielded concentrate compartments or electrochemical Faraday cages formed by porous electronically and ionically conductive media, instead of permselective ion exchange membranes. Due to local elimination of the applied electric field within the compartments, they electrostatically retain the incoming ions and act as 'electrostatic ion pumps' or 'ion traps' and therefore concentrate compartments. The porous media are chemically and thermally stable. Electrodeionization or electrodialysis cells containing such concentrate compartments in place of ion exchange membranes can be used to regenerate ion exchange resins and produce deionized water, to purify industrial effluents and desalinate brackish or seawater. The cells can work by polarity reversal without any negative impact to the deionization process. Because the electronically and ionically active media constituting the electrostatically shielded concentrate compartments are not permselective and coions are not repelled but can be swept by the migrating counterions, the cells are not affected by the known membrane associated limitations, such as concentration polarization or scaling and show an increased current efficiency.

  15. Shielding considerations for advanced space nuclear reactor systems

    Energy Technology Data Exchange (ETDEWEB)

    Angelo, J.P. Jr.; Buden, D.

    1982-01-01

    To meet the anticipated future space power needs, the Los Alamos National Laboratory is developing components for a compact, 100 kW/sub e/-class heat pipe nuclear reactor. The reactor uses uranium dioxide (UO/sub 2/) as its fuel, and is designed to operate around 1500 k. Heat pipes are used to remove thermal energy from the core without the use of pumps or compressors. The reactor heat pipes transfer mal energy to thermoelectric conversion elements that are advanced versions of the converters used on the enormously successful Voyager missions to the outer planets. Advanced versions of this heat pipe reactor could also be used to provide megawatt-level power plants. The paper reviews the status of this advanced heat pipe reactor and explores the radiation environments and shielding requirements for representative manned and unmanned applications.

  16. Induced Radioactivity in Lead Shielding at the National Synchrotron Light Source.

    Science.gov (United States)

    Ghosh, Vinita J; Schaefer, Charles; Kahnhauser, Henry

    2017-06-01

    The National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory was shut down in September 2014. Lead bricks used as radiological shadow shielding within the accelerator were exposed to stray radiation fields during normal operations. The FLUKA code, a fully integrated Monte Carlo simulation package for the interaction and transport of particles and nuclei in matter, was used to estimate induced radioactivity in this shielding and stainless steel beam pipe from known beam losses. The FLUKA output was processed using MICROSHIELD® to estimate on-contact exposure rates with individually exposed bricks to help design and optimize the radiological survey process. This entire process can be modeled using FLUKA, but use of MICROSHIELD® as a secondary method was chosen because of the project's resource constraints. Due to the compressed schedule and lack of shielding configuration data, simple FLUKA models were developed. FLUKA activity estimates for stainless steel were compared with sampling data to validate results, which show that simple FLUKA models and irradiation geometries can be used to predict radioactivity inventories accurately in exposed materials. During decommissioning 0.1% of the lead bricks were found to have measurable levels of induced radioactivity. Post-processing with MICROSHIELD® provides an acceptable secondary method of estimating residual exposure rates.

  17. S — Compactness Via Ideals

    OpenAIRE

    Abdel Monsef, M. E. [محمد عزت عبد المنصف; Lashien, E. F.; Nasef, A. A.

    1991-01-01

    Compactness modulo as an ideal has not been widely studied. Many new sorts of weak compactness have been introduced to topological spaces in the last twenty years but have not been studied using ideals. So, the main aim of our work is to study relations between ideals and some types of weak compactness. We initiate types of compactness modulo an ideal that generalize semi-compactness, S-closeness, S-Lindelofness and other types of compactness. Moreover, we study some of their properties and c...

  18. Saturn's rings thickness with the shadow hiding

    Science.gov (United States)

    Deau, Estelle; Brahic, André; Porco, Carolyn

    Using the Hapke shadow hiding model on various curves phases of ISS/Cassini, we were able to compute the thickness of Saturn's rings through the photometric filling factor. Our results show that diffuse rings (C ring and Cassini Division) are distributed in a monolayer with a thickness from a few centimeters to 5 meters. This seems to suggest that the layer is smaller than the larger particles. For the A and B rings, we find a thickness ranging from 10 to 20 meters, then leading to multiple layers of particles. Our results for the A ring are systematically lower than the values derived by density waves (Tiscareno et al., 2007) and dynamical simulations of Salo and Kaarjalainen (2003). For the first one, this can be explain by the fact the vertical height of the density waves are the upper limit of the real height. Indeed, the wakes (Julian & Toomre, 1966; Salo 1995) conduce the viscosity in the A ring (Daisaka et al., 2001), and produce random speeds greater in the ring plane than in the vertical direction (Daisaka & Ida, 1999), thereby reducing the thickness given by the vertical random speed used to compute the vertical height. However, for the latter one, simulations lead in all the cases (A and B rings such as C ring and Cassini Division) to vertical height of few meters. This constancy can be explained by the fact that simulations take a size distribution too truncated, and a coefficient of restitution rather simple (indeed, rings reflect different surface conditions related to the optical depth, thus the Bridges' law could not promote only one type of collisions). Finally, our results prefer monolayer (layer smaller than the larger particles which allow multilayer of smaller particules) for the faint rings (C ring and Cassini Division) and multilayer for the A and B rings.

  19. Compact Information Representations

    Science.gov (United States)

    2016-08-02

    detections (e.g., DDoS attacks), machine learning, databases, and search. Fundamentally, compact data representations are highly beneficial because they...engineering problems in data stream computations, real-time network monitoring & anomaly detections (e.g., DDoS attacks), machine learning, databases, and

  20. Granular compaction by fluidization

    Science.gov (United States)

    Tariot, Alexis; Gauthier, Georges; Gondret, Philippe

    2017-06-01

    How to arrange a packing of spheres is a scientific question that aroused many fundamental works since a long time from Kepler's conjecture to Edward's theory (S. F. Edwards and R.B.S Oakeshott. Theory of powders. Physica A, 157: 1080-1090, 1989), where the role traditionally played by the energy in statistical problems is replaced by the volume for athermal grains. We present experimental results on the compaction of a granular pile immersed in a viscous fluid when submited to a continuous or bursting upward flow. An initial fluidized bed leads to a well reproduced initial loose packing by the settling of grains when the high enough continuous upward flow is turned off. When the upward flow is then turned on again, we record the dynamical evolution of the bed packing. For a low enough continuous upward flow, below the critical velocity of fluidization, a slow compaction dynamics is observed. Strikingly, a slow compaction can be also observed in the case of "fluidization taps" with bursts of fluid velocity higher than the critical fluidization velocity. The different compaction dynamics is discussed when varying the different control parameters of these "fluidization taps".

  1. Highly Compact Composite Antenna

    OpenAIRE

    Pigeon, Mélusine; Morlaas-Courties, Christophe; Aubert, Hervé; Souny, Bernard

    2009-01-01

    International audience; The highly compact antenna proposed in this communication consists of a judicious association of equivalent magnetic current source with equivalent electric current source. This composite antenna presents a directivity radiation pattern analogous to one of the microstrip ceramic antennas but can be used at low frequencies. The antenna measurements confirm the promising performances obtained from electromagnetic simulations.

  2. Real Compact Surfaces

    Indian Academy of Sciences (India)

    The classification of real compact surfaces is a main result which is at the same time easy to understand and non- trivial, simple in formulation and rich in consequences. The aim of this article is to explain the theorem by means of many drawings. It is an invitation to a visual approach of mathematics. First Definitions and ...

  3. Soil Compaction Investigation.

    Science.gov (United States)

    Turski, Mark P.

    1988-01-01

    Describes a lab investigation designed to introduce students to soil compaction and help them to learn to design and adapt procedures that scientists use when they plan and conduct controlled investigations. Provided are objectives, a list of materials, procedures, and a sample student handout. (CW)

  4. Doctoring Undercover: updating the educational tradition of shadowing.

    Science.gov (United States)

    Clark, Claire D

    2017-01-01

    Premedical students are educated in basic biological and health sciences. As a complement to traditional premedical coursework, medical school applicants are encouraged to shadow practitioners, with the hope that observation will introduce students to the culture and practice of healthcare. Yet the shadowing experience varies widely across practitioners and institutions; resources that guide students' critical reflection and structure the experience are scarce. A pilot experiential learning course, Doctoring Undercover: Shadowing and the Culture of Medicine, was developed to fill this gap. The course consisted of three parts: an introduction to medical culture through the disciplines of medical sociology, history, anthropology, and bioethics; a site placement in which students applied these fields' analytical techniques to the study of medical culture and practice; and the development of an online activity guide that other premedical students may adapt to their shadowing circumstances. Students reported that they were exposed to new disciplinary perspectives and interprofessional environments that they would not traditionally encounter. Students' contributions to the shadowing guide encouraged active learning and reflection on the dynamics of effective patient-provider relationships and shadowing experiences. Locally, the class may be scaled for a larger group of premedical students and incorporated into a formal pathway program for premedical students; the content will also be integrated into the clinical medicine course for first-year medical students. Online, the guide will be promoted for use by other institutions and by individuals planning extracurricular shadowing experiences; feedback will be solicited. Tools for evaluating the short- and long-term impact of the course and guide will be developed and validated. Observational and experimental studies of the course's impact should be conducted. ICM: Introduction to Clinical Medicine; SCE: Selective Clinical

  5. Thermal neutron shield and method of manufacture

    Science.gov (United States)

    Brindza, Paul Daniel; Metzger, Bert Clayton

    2013-05-28

    A thermal neutron shield comprising concrete with a high percentage of the element Boron. The concrete is least 54% Boron by weight which maximizes the effectiveness of the shielding against thermal neutrons. The accompanying method discloses the manufacture of Boron loaded concrete which includes enriching the concrete mixture with varying grit sizes of Boron Carbide.

  6. Artificial Dielectric Shields for Integrated Transmission Lines

    NARCIS (Netherlands)

    Ma, Y.; Rejaei, B.; Zhuang, Y.

    2008-01-01

    We present a novel shielding method for on-chip transmission lines built on conductive silicon substrates. The shield consists of an artificial dielectric with a very high in-plane dielectric constant, built from two patterned metal layers isolated by a very thin dielectric film. Inserted below an

  7. Infrared shield facilitates optical pyrometer measurements

    Science.gov (United States)

    Eichenbrenner, F. F.; Illg, W.

    1965-01-01

    Water-cooled shield facilitates optical pyrometer high temperature measurements of small sheet metal specimens subjected to tensile stress in fatigue tests. The shield excludes direct or reflected radiation from one face of the specimen and permits viewing of the infrared radiation only.

  8. Isometric coactions of compact quantum groups on compact ...

    Indian Academy of Sciences (India)

    isometry group' in Rieffel's framework, we might expect it to be compact. Therefore, we gather some information on compact quantum groups and compact quantum metric spaces together with other preliminary notions in the second section. Next, we introduce our notion of isometric coactions in the third section. We show in ...

  9. How Concentration Shields Against Distraction.

    Science.gov (United States)

    Sörqvist, Patrik; Marsh, John E

    2015-08-01

    In this article, we outline our view of how concentration shields against distraction. We argue that higher levels of concentration make people less susceptible to distraction for two reasons. One reason is that the undesired processing of the background environment is reduced. For example, when people play a difficult video game, as opposed to an easy game, they are less likely to notice what people in the background are saying. The other reason is that the locus of attention becomes more steadfast. For example, when people are watching an entertaining episode of their favorite television series, as opposed to a less absorbing show, attention is less likely to be diverted away from the screen by a ringing telephone. The theoretical underpinnings of this perspective, and potential implications for applied settings, are addressed.

  10. Radiation Shielding Systems Using Nanotechnology

    Science.gov (United States)

    Chen, Bin (Inventor); McKay, Christoper P. (Inventor)

    2011-01-01

    A system for shielding personnel and/or equipment from radiation particles. In one embodiment, a first substrate is connected to a first array or perpendicularly oriented metal-like fingers, and a second, electrically conducting substrate has an array of carbon nanostructure (CNS) fingers, coated with an electro-active polymer extending toward, but spaced apart from, the first substrate fingers. An electric current and electric charge discharge and dissipation system, connected to the second substrate, receives a current and/or voltage pulse initially generated when the first substrate receives incident radiation. In another embodiment, an array of CNSs is immersed in a first layer of hydrogen-rich polymers and in a second layer of metal-like material. In another embodiment, a one- or two-dimensional assembly of fibers containing CNSs embedded in a metal-like matrix serves as a radiation-protective fabric or body covering.

  11. PC based temporary shielding administrative procedure (TSAP)

    Energy Technology Data Exchange (ETDEWEB)

    Olsen, D.E.; Pederson, G.E. [Sargent & Lundy, Chicago, IL (United States); Hamby, P.N. [Commonwealth Edison Co., Downers Grove, IL (United States)

    1995-03-01

    A completely new Administrative Procedure for temporary shielding was developed for use at Commonwealth Edison`s six nuclear stations. This procedure promotes the use of shielding, and addresses industry requirements for the use and control of temporary shielding. The importance of an effective procedure has increased since more temporary shielding is being used as ALARA goals become more ambitious. To help implement the administrative procedure, a personal computer software program was written to incorporate the procedural requirements. This software incorporates the useability of a Windows graphical user interface with extensive help and database features. This combination of a comprehensive administrative procedure and user friendly software promotes the effective use and management of temporary shielding while ensuring that industry requirements are met.

  12. Progress in Compact Toroid Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Dolan, Thomas James

    2002-09-01

    The term "compact toroids" as used here means spherical tokamaks, spheromaks, and field reversed configurations, but not reversed field pinches. There are about 17 compact toroid experiments under construction or operating, with approximate parameters listed in Table 1.

  13. The interrupted power law and the size of shadow banking.

    Science.gov (United States)

    Fiaschi, Davide; Kondor, Imre; Marsili, Matteo; Volpati, Valerio

    2014-01-01

    Using public data (Forbes Global 2000) we show that the asset sizes for the largest global firms follow a Pareto distribution in an intermediate range, that is "interrupted" by a sharp cut-off in its upper tail, where it is totally dominated by financial firms. This flattening of the distribution contrasts with a large body of empirical literature which finds a Pareto distribution for firm sizes both across countries and over time. Pareto distributions are generally traced back to a mechanism of proportional random growth, based on a regime of constant returns to scale. This makes our findings of an "interrupted" Pareto distribution all the more puzzling, because we provide evidence that financial firms in our sample should operate in such a regime. We claim that the missing mass from the upper tail of the asset size distribution is a consequence of shadow banking activity and that it provides an (upper) estimate of the size of the shadow banking system. This estimate-which we propose as a shadow banking index-compares well with estimates of the Financial Stability Board until 2009, but it shows a sharper rise in shadow banking activity after 2010. Finally, we propose a proportional random growth model that reproduces the observed distribution, thereby providing a quantitative estimate of the intensity of shadow banking activity.

  14. eShadow: A tool for comparing closely related sequences

    Energy Technology Data Exchange (ETDEWEB)

    Ovcharenko, Ivan; Boffelli, Dario; Loots, Gabriela G.

    2004-01-15

    Primate sequence comparisons are difficult to interpret due to the high degree of sequence similarity shared between such closely related species. Recently, a novel method, phylogenetic shadowing, has been pioneered for predicting functional elements in the human genome through the analysis of multiple primate sequence alignments. We have expanded this theoretical approach to create a computational tool, eShadow, for the identification of elements under selective pressure in multiple sequence alignments of closely related genomes, such as in comparisons of human to primate or mouse to rat DNA. This tool integrates two different statistical methods and allows for the dynamic visualization of the resulting conservation profile. eShadow also includes a versatile optimization module capable of training the underlying Hidden Markov Model to differentially predict functional sequences. This module grants the tool high flexibility in the analysis of multiple sequence alignments and in comparing sequences with different divergence rates. Here, we describe the eShadow comparative tool and its potential uses for analyzing both multiple nucleotide and protein alignments to predict putative functional elements. The eShadow tool is publicly available at http://eshadow.dcode.org/

  15. The Interrupted Power Law and the Size of Shadow Banking

    Science.gov (United States)

    Fiaschi, Davide; Kondor, Imre; Marsili, Matteo; Volpati, Valerio

    2014-01-01

    Using public data (Forbes Global 2000) we show that the asset sizes for the largest global firms follow a Pareto distribution in an intermediate range, that is “interrupted” by a sharp cut-off in its upper tail, where it is totally dominated by financial firms. This flattening of the distribution contrasts with a large body of empirical literature which finds a Pareto distribution for firm sizes both across countries and over time. Pareto distributions are generally traced back to a mechanism of proportional random growth, based on a regime of constant returns to scale. This makes our findings of an “interrupted” Pareto distribution all the more puzzling, because we provide evidence that financial firms in our sample should operate in such a regime. We claim that the missing mass from the upper tail of the asset size distribution is a consequence of shadow banking activity and that it provides an (upper) estimate of the size of the shadow banking system. This estimate–which we propose as a shadow banking index–compares well with estimates of the Financial Stability Board until 2009, but it shows a sharper rise in shadow banking activity after 2010. Finally, we propose a proportional random growth model that reproduces the observed distribution, thereby providing a quantitative estimate of the intensity of shadow banking activity. PMID:24728096

  16. Using Shadow Page Cache to Improve Isolated Drivers Performance

    Directory of Open Access Journals (Sweden)

    Hao Zheng

    2015-01-01

    Full Text Available With the advantage of the reusability property of the virtualization technology, users can reuse various types and versions of existing operating systems and drivers in a virtual machine, so as to customize their application environment. In order to prevent users’ virtualization environments being impacted by driver faults in virtual machine, Chariot examines the correctness of driver’s write operations by the method of combining a driver’s write operation capture and a driver’s private access control table. However, this method needs to keep the write permission of shadow page table as read-only, so as to capture isolated driver’s write operations through page faults, which adversely affect the performance of the driver. Based on delaying setting frequently used shadow pages’ write permissions to read-only, this paper proposes an algorithm using shadow page cache to improve the performance of isolated drivers and carefully study the relationship between the performance of drivers and the size of shadow page cache. Experimental results show that, through the shadow page cache, the performance of isolated drivers can be greatly improved without impacting Chariot’s reliability too much.

  17. The use of nipple shields: A review

    Directory of Open Access Journals (Sweden)

    Selina Chow

    2016-11-01

    Full Text Available A nipple shield is a breastfeeding aid with a nipple-shaped shield that is positioned over the nipple and areola prior to nursing. Nipple shields are usually recommended to mothers with flat nipples or in cases in which there is a failure of the baby to effectively latch onto the breast within the first two days postpartum. The use of nipple shields is a controversial topic in the field of lactation. Its use has been an issue in the clinical literature since some older studies discovered reduced breast milk transfer when using nipple shields, while more recent studies reported successful breastfeeding outcomes. The purpose of this review was to examine the evidence and outcomes with nipple shield use. Methods: A literature search was conducted in Ovid MEDLINE, OLDMEDLINE, EMBASE Classic, EMBASE, Cochrane Central Register of Controlled Trials and CINAHL. The primary endpoint was any breastfeeding outcome following nipple shield use. Secondary endpoints included the reasons for nipple shield use and the average/median length of use. For the analysis, we examined the effect of nipple shield use on physiological responses, premature infants, mothers’ experiences, and health professionals’ experiences. Results: The literature search yielded 261 articles, 14 of which were included in this review. Of these 14 articles, three reported on physiological responses, two reported on premature infants, eight reported on mothers’ experiences, and one reported on health professionals’ experiences. Conclusion: Through examining the use of nipple shields, further insight is provided on the advantages and disadvantages of this practice, thus allowing clinicians and researchers to address improvements on areas that will benefit mothers and infants the most.

  18. Weakly compact operators and interpolation

    OpenAIRE

    Maligranda, Lech

    1992-01-01

    The class of weakly compact operators is, as well as the class of compact operators, a fundamental operator ideal. They were investigated strongly in the last twenty years. In this survey, we have collected and ordered some of this (partly very new) knowledge. We have also included some comments, remarks and examples. The class of weakly compact operators is, as well as the class of compact operators, a fundamental operator ideal. They were investigated strongly in the last twenty years. I...

  19. Simple and Efficient Decoupling of Compact Arrays With Parasitic Scatterers

    DEFF Research Database (Denmark)

    Lau, B.K.; Andersen, Jørgen Bach

    2012-01-01

    Compact arrays such as multiple antennas on a mobile terminal suffer from low efficiency and high correlation between antenna signals. In the present paper, a simple and rigorous procedure for decoupling two closely coupled antennas with a parasitic scatterer is proposed. The parasitic scatterer......, which can be an additional antenna, acts as a shield between two active antenna elements. In contrast to previous studies involving the use of parasitic scatterer for decoupling antennas, we demonstrate using antenna impedances the underlying decoupling mechanism for two arbitrary antennas. By a proper...

  20. Compact fusion reactors

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    Fusion research is currently to a large extent focused on tokamak (ITER) and inertial confinement (NIF) research. In addition to these large international or national efforts there are private companies performing fusion research using much smaller devices than ITER or NIF. The attempt to achieve fusion energy production through relatively small and compact devices compared to tokamaks decreases the costs and building time of the reactors and this has allowed some private companies to enter the field, like EMC2, General Fusion, Helion Energy, Lawrenceville Plasma Physics and Lockheed Martin. Some of these companies are trying to demonstrate net energy production within the next few years. If they are successful their next step is to attempt to commercialize their technology. In this presentation an overview of compact fusion reactor concepts is given.

  1. Compact Spreader Schemes

    Energy Technology Data Exchange (ETDEWEB)

    Placidi, M.; Jung, J. -Y.; Ratti, A.; Sun, C.

    2014-07-25

    This paper describes beam distribution schemes adopting a novel implementation based on low amplitude vertical deflections combined with horizontal ones generated by Lambertson-type septum magnets. This scheme offers substantial compactness in the longitudinal layouts of the beam lines and increased flexibility for beam delivery of multiple beam lines on a shot-to-shot basis. Fast kickers (FK) or transverse electric field RF Deflectors (RFD) provide the low amplitude deflections. Initially proposed at the Stanford Linear Accelerator Center (SLAC) as tools for beam diagnostics and more recently adopted for multiline beam pattern schemes, RFDs offer repetition capabilities and a likely better amplitude reproducibility when compared to FKs, which, in turn, offer more modest financial involvements both in construction and operation. Both solutions represent an ideal approach for the design of compact beam distribution systems resulting in space and cost savings while preserving flexibility and beam quality.

  2. Improved Metal-Polymeric Laminate Radiation Shielding Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this proposed Phase I program, a multifunctional lightweight radiation shield composite will be developed and fabricated. This structural radiation shielding will...

  3. Foam-Reinforced Polymer Matrix Composite Radiation Shields Project

    Data.gov (United States)

    National Aeronautics and Space Administration — New and innovative lightweight radiation shielding materials are needed to protect humans in future manned exploration vehicles. Radiation shielding materials are...

  4. Physical models for moving shadow and object detection in video.

    Science.gov (United States)

    Nadimi, Sohail; Bhanu, Bir

    2004-08-01

    Current moving object detection systems typically detect shadows cast by the moving object as part of the moving object. In this paper, the problem of separating moving cast shadows from the moving objects in an outdoor environment is addressed. Unlike previous work, we present an approach that does not rely on any geometrical assumptions such as camera location and ground surface/object geometry. The approach is based on a new spatio-temporal albedo test and dichromatic reflection model and accounts for both the sun and the sky illuminations. Results are presented for several video sequences representing a variety of ground materials when the shadows are cast on different surface types. These results show that our approach is robust to widely different background and foreground materials, and illuminations.

  5. Multiple shooting shadowing for sensitivity analysis of chaotic dynamical systems

    Science.gov (United States)

    Blonigan, Patrick J.; Wang, Qiqi

    2018-02-01

    Sensitivity analysis methods are important tools for research and design with simulations. Many important simulations exhibit chaotic dynamics, including scale-resolving turbulent fluid flow simulations. Unfortunately, conventional sensitivity analysis methods are unable to compute useful gradient information for long-time-averaged quantities in chaotic dynamical systems. Sensitivity analysis with least squares shadowing (LSS) can compute useful gradient information for a number of chaotic systems, including simulations of chaotic vortex shedding and homogeneous isotropic turbulence. However, this gradient information comes at a very high computational cost. This paper presents multiple shooting shadowing (MSS), a more computationally efficient shadowing approach than the original LSS approach. Through an analysis of the convergence rate of MSS, it is shown that MSS can have lower memory usage and run time than LSS.

  6. The fingerprints of black holes—shadows and their degeneracies

    Science.gov (United States)

    Mars, Marc; Paganini, Claudio F.; Oancea, Marius A.

    2018-01-01

    We show that, away from the axis of symmetry, no continuous degeneration exists between the shadows of observers at any point in the exterior region of any Kerr–Newman black hole spacetime of unit mass. Therefore, except possibly for discrete changes, an observer can, by measuring the black holes shadow, determine the angular momentum and the charge of the black hole under observation as well as the observer’s radial position and angle of elevation above the equatorial plane. Furthermore, his/her relative velocity compared to a standard observer can also be measured. However, the black hole shadow does not allow for a full parameter resolution in the case of a Kerr–Newman–Taub–NUT black hole, as a continuous degeneration relating specific angular momentum, electric charge, Taub–NUT charge and elevation angle exists in this case.

  7. Compaction of cereal grain

    OpenAIRE

    Wychowaniec, J.; Griffiths, I.; Gay, A; Mughal, A.

    2013-01-01

    We report on simple shaking experiments to measure the compaction of a column of Firth oat grain. Such grains are elongated anisotropic particles with a bimodal polydispersity. In these experiments, the particle configurations start from an initially disordered, low-packing-fraction state and under vertical shaking evolve to a dense state with evidence of nematic-like structure at the surface of the confining tube. This is accompanied by an increase in the packing fraction of the grain.

  8. Compaction of cereal grain

    Science.gov (United States)

    Wychowaniec, J.; Griffiths, I.; Gay, A.; Mughal, A.

    2013-11-01

    We report on simple shaking experiments to measure the compaction of a column of Firth oat grain. Such grains are elongated anisotropic particles with a bimodal polydispersity. In these experiments, the particle configurations start from an initially disordered, low-packing-fraction state and under vertical shaking evolve to a dense state with evidence of nematic-like structure at the surface of the confining tube. This is accompanied by an increase in the packing fraction of the grain.

  9. Compact simulator technology

    Energy Technology Data Exchange (ETDEWEB)

    Fray, R.; Divakaruni, M. (Electric Power Research Inst., Palo Alto, CA (United States))

    1992-03-01

    In its work to expand and enhance simulator-based training in the fossil generation industry, EPRI is developing compact simulator technology for training power plant operators. These personal computer-based systems are more flexible and much less expensive than conventional, mainframe-based simulators, and their use can dramatically increase operator effectiveness. The potential benefits for utilities include improved plant performance, availability, life, and environmental compliance and thus significantly lower O and M costs.

  10. The Dark Shadow of Virtual Reality

    Directory of Open Access Journals (Sweden)

    Claire Su-Yeon Park

    2018-01-01

    Full Text Available Virtual Reality (VR technology are entering nursing education at a rapid speed (Foronda et al., 2017. VR has been reported in the nursing literature to significantly improve students’ performance (Jenson & Forsyth, 2012; Park, 2016; Foronda et al., 2017 even though the body of evidence in terms of the number and research quality of peer reviewed research papers is not yet substantial enough to identify VR technology’s effectiveness. However, VR is not actually reality. VR may not actually reflect reality. Young people (and even adults may not perceive the different between reality and VR. They may not yet be mature enough to distinguish the difference. However, VR technology are going much further than traditional educational methods by allowing humans to experience a much higher level of immersion through a virtual image. Even the gap between advances in VR technology and its application to education science is widening, causing serious concern. The advance in VR technology is value-neutral. As with all things, whether something is good or bad depends on how humans use it. VR can be useful, for example, when it enables scholars to attend an international conference without traveling to the physical convention center. VR provides the ability to speak, listen, and discuss in real time. Those using VR can choose to view a featured or real-time image of the other participants as if they were actually at the conference. Further, remote participants can feel touch through electronic sensors attached to their body. How amazing! The problem with VR lies in the fact that we are not ready to cope with any possible harmful influences caused by advances in VR technology. But what is the “Dark Shadow of VR,” and why does it cause concern, particularly in pedagogy? Luc Besson’s 2017 film Valerian and the City of a Thousand Plants showed an exceptional VR world, “Big Market,” a shopping-focused VR platform. But such a world is no longer strictly

  11. Shadow correction in high dynamic range images for generating orthophotos

    Science.gov (United States)

    Suzuki, Hideo; Chikatsu, Hirofumi

    2011-07-01

    High dynamic range imagery is widely used in remote sensing. With the widespread use of aerial digital cameras such as the DMC, ADS40, RMK-D, and UltraCamD, high dynamic range imaging is generally expected for generating minuteness orthophotos in digital aerial photogrammetry. However, high dynamic range images (12-bit, 4,096 gray levels) are generally compressed into an 8-bit depth digital image (256 gray levels) owing to huge amount of data and interface with peripherals such as monitors and printers. This means that a great deal of image data is eliminated from the original image, and this introduces a new shadow problem. In particular, the influence of shadows in urban areas causes serious problems when generating minuteness orthophotos and performing house detection. Therefore, shadow problems can be solved by addressing the image compression problems. There is a large body of literature on image compression techniques such as logarithmic compression and tone mapping algorithms. However, logarithmic compression tends to cause loss of details in dark and/or light areas. Furthermore, the logarithmic method intends to operate on the full scene. This means that high-resolution luminance information can not be obtained. Even though tone mapping algorithms have the ability to operate over both full scene and local scene, background knowledge is required. To resolve the shadow problem in digital aerial photogrammetry, shadow areas should be recognized and corrected automatically without the loss of luminance information. To this end, a practical shadow correction method using 12-bit real data acquired by DMC is investigated in this paper.

  12. Radiation shield for operator under radiation circumference

    Energy Technology Data Exchange (ETDEWEB)

    Nemezawa, Isao; Kimura, Tadahiro [Hitachi Ltd., Tokyo (Japan); Omori, Tetsu; Mizuochi, Akira

    1997-11-18

    A radiation shield for an upper half of a man`s body comprises a synthetic resin clothing, a rubber plate or a composite member of them formed into a bag. The bag is formed three dimensionally in the form of an open in front vest. A radiation shielding bag for the lower half of a man`s body is formed into three dimensionally in the form of open in front half trousers. A water injection port for injecting water as shielding liquid and a gas exhaust port are formed to each of the bags. Upon operation under radiation circumstance, the water injection ports and the gas exhaustion ports are opened, and shielding liquid is injected from the water injection ports to the bag so that the shielding liquid shields radiation rays. After closing the water injection ports and the gas exhaustion ports, an operator wears and buttons up the radiation shield of the upper half and the lower half to protect radiation exposure from the front, back and the side of a man. (I.N.)

  13. Development of neutron shielding material for cask

    Energy Technology Data Exchange (ETDEWEB)

    Najima, K.; Ohta, H.; Ishihara, N. [Mitsubishi Heavy Industries Ltd., Takasago Research and Development Center, Hyogo (Japan); Matsuoka, T.; Kuri, S.; Ohsono, K.; Hode, S. [Mitsubishi Heavy Industries Ltd., Kobe Shipyard and Machinery Works, Kobe (Japan)

    2001-07-01

    Since 1980's Mitsubishi Heavy Industries, Ltd (MHI) has established transport and storage cask design 'MSF series' which makes higher payload and reliability for long term storage. MSF series transport and storage cask uses new-developed neutron shielding material. This neutron shielding material has been developed for improving durability under high condition for long term. Since epoxy resin contains a lot of hydrogen and is comparatively resistant to heat, many casks employ epoxy base neutron shielding material. However, if the epoxy base neutron shielding material is used under high temperature condition for a long time, the material deteriorates and the moisture contained in it is released. The loss of moisture is in the range of several percents under more than 150 C. For this reason, our purpose was to develop a high durability epoxy base neutron shielding material which has the same self-fire-extinction property, high hydrogen content and so on as conventional. According to the long-time heating test, the weight loss of this new neutron shielding material after 5000 hours heating has been lower than 0.04% at 150 C and 0.35% at 170 C. A thermal test was also performed: a specimen of neutron shielding material covered with stainless steel was inserted in a furnace under condition of 800 C temperature for 30 minutes then was left to cool down in ambient conditions. The external view of the test piece shows that only a thin layer was carbonized.

  14. Extraterrestrial Regolith Derived Atmospheric Entry Heat Shields

    Science.gov (United States)

    Hogue, Michael D.; Mueller, Robert P.; Sibille, Laurent; Hintze, Paul E.; Rasky, Daniel J.

    2016-01-01

    High-mass planetary surface access is one of NASAs technical challenges involving entry, descent and landing (EDL). During the entry and descent phase, frictional interaction with the planetary atmosphere causes a heat build-up to occur on the spacecraft, which will rapidly destroy it if a heat shield is not used. However, the heat shield incurs a mass penalty because it must be launched from Earth with the spacecraft, thus consuming a lot of precious propellant. This NASA Innovative Advanced Concept (NIAC) project investigated an approach to provide heat shield protection to spacecraft after launch and prior to each EDL thus potentially realizing significant launch mass savings. Heat shields fabricated in situ can provide a thermal-protection system for spacecraft that routinely enter a planetary atmosphere. By fabricating the heat shield with space resources from materials available on moons and asteroids, it is possible to avoid launching the heat-shield mass from Earth. Regolith has extremely good insulating properties and the silicates it contains can be used in the fabrication and molding of thermal-protection materials. In this paper, we will describe three types of in situ fabrication methods for heat shields and the testing performed to determine feasibility of this approach.

  15. Roughness of sandstone fracture surfaces: Profilometry and shadow length investigations

    OpenAIRE

    Boffa, Jean-Marc; Allain, C.; Chertcoff, R.; Hulin, Jean-Pierre; Plouraboué, Franck; Roux, Stéphane

    1999-01-01

    The geometrical properties of fractured sandstone surfaces were studied by measuring the length distribution of the shadows appearing under grazing illumination. Three distinct domains of variation were found: at short length scales a cut-off of self-affinity is observed due to the inter-granular rupture of sandstones, at long length scales, the number of shadows falls off very rapidly because of the non-zero illumination angle and of the finite roughness amplitude. Finally, in the intermediate do...

  16. Wake models developed during the Wind Shadow Project

    DEFF Research Database (Denmark)

    Larsen, Søren Ejling; Ott, Søren; Pena Diaz, Alfredo

    The Wind Shadow project has developed and validated improved models for determining the wakes losses, and thereby the array efficiency of very large, closely packed wind farms. The rationale behind the project has been that the existing software has been covering these types of wind farms poorly......, both with respect to the densely packed turbines and the large fetches needed to describe the collective shadow effects of one farm to the next. Further the project has developed the necessary software for the use of the models. Guidelines with recommendations for the use of the models are included...... in the model deliverables....

  17. Estimating Outdoor Illumination Conditions Based on Detection of Dynamic Shadows

    DEFF Research Database (Denmark)

    Madsen, Claus B.; Lal, Brajesh Behari

    2013-01-01

    The paper proposes a technique for estimation outdoor illumination conditions in terms of sun and sky radiances directly from pixel values of dynamic shadows detected in video sequences produved by a commercial stereo camera. The technique is applied to the rendering of virtual object into the im......The paper proposes a technique for estimation outdoor illumination conditions in terms of sun and sky radiances directly from pixel values of dynamic shadows detected in video sequences produved by a commercial stereo camera. The technique is applied to the rendering of virtual object...

  18. PWR upper/lower internals shield

    Energy Technology Data Exchange (ETDEWEB)

    Homyk, W.A. [Indian Point Station, Buchanan, NY (United States)

    1995-03-01

    During refueling of a nuclear power plant, the reactor upper internals must be removed from the reactor vessel to permit transfer of the fuel. The upper internals are stored in the flooded reactor cavity. Refueling personnel working in containment at a number of nuclear stations typically receive radiation exposure from a portion of the highly contaminated upper intervals package which extends above the normal water level of the refueling pool. This same issue exists with reactor lower internals withdrawn for inservice inspection activities. One solution to this problem is to provide adequate shielding of the unimmersed portion. The use of lead sheets or blankets for shielding of the protruding components would be time consuming and require more effort for installation since the shielding mass would need to be transported to a support structure over the refueling pool. A preferable approach is to use the existing shielding mass of the refueling pool water. A method of shielding was devised which would use a vacuum pump to draw refueling pool water into an inverted canister suspended over the upper internals to provide shielding from the normally exposed components. During the Spring 1993 refueling of Indian Point 2 (IP2), a prototype shield device was demonstrated. This shield consists of a cylindrical tank open at the bottom that is suspended over the refueling pool with I-beams. The lower lip of the tank is two feet below normal pool level. After installation, the air width of the natural shielding provided by the existing pool water. This paper describes the design, development, testing and demonstration of the prototype device.

  19. Hydraulic conductivity of compacted zeolites.

    Science.gov (United States)

    Oren, A Hakan; Ozdamar, Tuğçe

    2013-06-01

    Hydraulic conductivities of compacted zeolites were investigated as a function of compaction water content and zeolite particle size. Initially, the compaction characteristics of zeolites were determined. The compaction test results showed that maximum dry unit weight (γ(dmax)) of fine zeolite was greater than that of granular zeolites. The γ(dmax) of compacted zeolites was between 1.01 and 1.17 Mg m(-3) and optimum water content (w(opt)) was between 38% and 53%. Regardless of zeolite particle size, compacted zeolites had low γ(dmax) and high w(opt) when compared with compacted natural soils. Then, hydraulic conductivity tests were run on compacted zeolites. The hydraulic conductivity values were within the range of 2.0 × 10(-3) cm s(-1) to 1.1 × 10(-7) cm s(-1). Hydraulic conductivity of all compacted zeolites decreased almost 50 times as the water content increased. It is noteworthy that hydraulic conductivity of compacted zeolite was strongly dependent on the zeolite particle size. The hydraulic conductivity decreased almost three orders of magnitude up to 39% fine content; then, it remained almost unchanged beyond 39%. Only one report was found in the literature on the hydraulic conductivity of compacted zeolite, which is in agreement with the findings of this study.

  20. Intraplate Seismicity in Fennoscandian Shield

    Science.gov (United States)

    Korja, Annakaisa; Uski, Marja

    2017-04-01

    Fennoscandian Shield is situated in a seismically quiet intraplate setting in northern Europe. Based on a subset of the most recent earthquake data (2000-2012), most of the earthquakes (80%) occur in the upper crust down to 17 km in depth, a minority (19%) in the middle crust (17-31 km) and only a few in the lower crust 31-45 km (1%). The seismogenic layer is less than 30 km in depth and has a rather uniform thickness across Fennoscandian Shield. Reflection profiles suggest only few of the outcropping deformation zones penetrate the upper-middle crustal layer boundary and even fewer reach the lower crust. We suggest that the middle to lower crustal boundary may add compositional and rheological constraints to the depth extent of the seismogenic zone The orientation of the overall maximum horizontal stress field in northern Europe is WNW-ESE to NW-SE. The current strain rates are rather low and thus cannot produce new structures but rather reactivate old structures where stress overcomes fault friction. Pre-existing deformation zones that are optimally oriented in the present stress field can potentially be reactivated. The deformation zones were analysed for their length and azimuth and they were assigned a potential reactivation type (reverse, normal or strike slip) based solely on their azimuth. The earthquakes in the seismically most active area, close to Skellefteå, Sweden along the western coast of the Gulf of Bothnia and its north-easterly continuation, appear to cluster around the shoreline and along post-glacial faults, which are mostly oriented optimally for reverse or strike slip faulting. The seismically active Kuusamo area in Finland is transacted by wealth of deformation zones all trending in directions optimal for reactivation. The fault plane solutions of the most recent moderate size surprise earthquakes (Sveg 15.9.2014 Ml 4.4, Bothnian Bay 19.3.2016 Ml 4.1) suggest strike slip movement in optimally oriented for strike slip faulting according to

  1. Verification of Aerosol Optical Depth Retrievals using Cloud Shadows Retrieved from Satellite Imagery

    National Research Council Canada - National Science Library

    Sweat, Perry C

    2008-01-01

    ...), IKONOS, and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). The lower resolution of MODIS and ASTER does not lend itself to focusing on building shadows, but rather cloud shadows...

  2. X-ray shielding behaviour of kaolin derived mullite-barites ceramic

    Science.gov (United States)

    Ripin, A.; Mohamed, F.; Choo, T. F.; Yusof, M. R.; Hashim, S.; Ghoshal, S. K.

    2018-03-01

    Mullite-barite ceramic (MBC) is an emergent material for effective shielding of redundant ionizing radiation exposure. The composition dependent mechanical, thermal, and microstructure properties of MBC that makes MBC a high performing novel radiation shielding candidate remained unexplored. This paper examines the possibility of exploiting Malaysian kaolin (AKIM-35) and barite (BaSO4) derived ceramic (MBC) system for X-ray shielding operation. Using conventional pressing and sintering method six ceramic samples are prepared by mixing AKIM-35 with barite at varying contents (0, 10, 20, 30, 40 and 50 wt%). Synthesized pressed mixtures are calcined at 400 °C for 30 min and then sintered to 1300 °C for 120 min at a heating rate of 10 °C/min. Sintered samples are characterized via X-ray Diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), lead equivalent (LE), uniformity and dose reduction analyses. XRD pattern of prepared ceramics revealed the presence of monoclinic barium alumino-silicate (BAS) and orthorhombic mullite as major shielding phases together with other minor phase of barite and hexagonal quartz (SiO2) structures. Furthermore, FESEM images of ceramics (between 0 and 30 wt%) displayed the existence of compacted monoclinic plate of BAS and acicular mullite morphology (ceramics at 40 and 50 wt%). Radiation tests displayed the capacity of ceramics (at 0 and 10 wt%) to shield the X-ray radiation emanated at tube potential range of 50-120 kV. The highest radiation attenuation is ascertained at 70 kV where the dose is reduced remarkably between 99.11% and 97.42%. Ceramics at 0 and 10 wt% demonstrated the highest lead (Pb) equivalent thickness (LE) of 0.44 mm and 0.34 mm, respectively. It is established that such MBC may contribute towards the development of shielding material against ionizing radiation in diagnostic radiology (X-ray) dose range.

  3. SU-E-T-556: Monte Carlo Generated Dose Distributions for Orbital Irradiation Using a Single Anterior-Posterior Electron Beam and a Hanging Lens Shield

    Energy Technology Data Exchange (ETDEWEB)

    Duwel, D [Cincinnati, OH (United States); Lamba, M; Elson, H; Kumar, N [University of Cincinnati, Cincinnati, OH (United States)

    2015-06-15

    Purpose: Various cancers of the eye are successfully treated with radiotherapy utilizing one anterior-posterior (A/P) beam that encompasses the entire content of the orbit. In such cases, a hanging lens shield can be used to spare dose to the radiosensitive lens of the eye to prevent cataracts. Methods: This research focused on Monte Carlo characterization of dose distributions resulting from a single A-P field to the orbit with a hanging shield in place. Monte Carlo codes were developed which calculated dose distributions for various electron radiation energies, hanging lens shield radii, shield heights above the eye, and beam spoiler configurations. Film dosimetry was used to benchmark the coding to ensure it was calculating relative dose accurately. Results: The Monte Carlo dose calculations indicated that lateral and depth dose profiles are insensitive to changes in shield height and electron beam energy. Dose deposition was sensitive to shield radius and beam spoiler composition and height above the eye. Conclusion: The use of a single A/P electron beam to treat cancers of the eye while maintaining adequate lens sparing is feasible. Shield radius should be customized to have the same radius as the patient’s lens. A beam spoiler should be used if it is desired to substantially dose the eye tissues lying posterior to the lens in the shadow of the lens shield. The compromise between lens sparing and dose to diseased tissues surrounding the lens can be modulated by varying the beam spoiler thickness, spoiler material composition, and spoiler height above the eye. The sparing ratio is a metric that can be used to evaluate the compromise between lens sparing and dose to surrounding tissues. The higher the ratio, the more dose received by the tissues immediately posterior to the lens relative to the dose received by the lens.

  4. Long Duration Space Shelter Shielding Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Physical Sciences Inc. (PSI) has developed a ceramic composite material system that is more effective for shielding both GCR and SPE than aluminum. The composite...

  5. Thermal Shield and Reactor Structure Temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Collier, A.R.

    2001-07-31

    The purpose of this report is to present reactor structure and thermal shield temperature data taken during P-3 and P-5 cycles and compare them with design calculations in order to predict temperatures at higher power levels.

  6. Shielded ADR Magnets For Space Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Phase II program will concentrate on manufacturing of qualified low-current, light-weight, 10K ADR magnets for space application. Shielded ADR solenoidal magnets...

  7. Additional shielding in front of M2

    CERN Document Server

    Schmidt, B

    2013-01-01

    This note presents studies on possibilities to improve the shielding in front of M2 in order to reduce occupancy of the hottest areas of the Muon System and to mitigate the dead-time problem. Two places for installing additional shielding have been considered: behind HCAL, in place of the PMTs and their bases for the readout, and inside ECAL, in place of the innermost modules of the calorimeter. Studies on the additional shielding inside ECAL have been done for the complementarity of the research rather than for practical purpose due negative effects on the physics. Various studies have been carried out and different configurations of shielding in terms of dimensions and materials have been tested using MC simulations. Moreover the correlation between hits was studied by analysing angles of the tracks passing through M2.

  8. Long Duration Space Shelter Shielding Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Physical Sciences Inc. (PSI) has developed fiber reinforced ceramic composites for radiation shielding that can be used for external walls in long duration manned...

  9. Shielded ADR Magnets For Space Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — An important consideration of the use of superconducting magnets in ADR applications is shielding of the other instruments in the vicinity of the superconducting...

  10. Rainbow scattering in the gravitational field of a compact object

    Science.gov (United States)

    Dolan, Sam R.; Stratton, Tom

    2017-06-01

    We study the elastic scattering of a planar wave in the curved spacetime of a compact object such as a neutron star, via a heuristic model: a scalar field impinging upon a spherically symmetric uniform density star of radius R and mass M . For R rc, there instead arises a stationary point in the deflection function which creates a caustic and rainbow scattering. As in nuclear rainbow scattering, there is an Airy-type oscillation on a Rutherford-like cross section, followed by a shadow zone. We show that, for R ˜3.5 G M /c2, the rainbow angle lies close to 180°, and thus there arises enhanced backscattering and glory. We explore possible implications for gravitational wave astronomy and dark matter models.

  11. Using gradient-based ray and candidate shadow maps for environmental illumination distribution estimation

    Science.gov (United States)

    Eem, Changkyoung; Kim, Iksu; Hong, Hyunki

    2015-07-01

    A method to estimate the environmental illumination distribution of a scene with gradient-based ray and candidate shadow maps is presented. In the shadow segmentation stage, we apply a Canny edge detector to the shadowed image by using a three-dimensional (3-D) augmented reality (AR) marker of a known size and shape. Then the hierarchical tree of the connected edge components representing the topological relation is constructed, and the connected components are merged, taking their hierarchical structures into consideration. A gradient-based ray that is perpendicular to the gradient of the edge pixel in the shadow image can be used to extract the shadow regions. In the light source detection stage, shadow regions with both a 3-D AR marker and the light sources are partitioned into candidate shadow maps. A simple logic operation between each candidate shadow map and the segmented shadow is used to efficiently compute the area ratio between them. The proposed method successively extracts the main light sources according to their relative contributions on the segmented shadows. The proposed method can reduce unwanted effects due to the sampling positions in the shadow region and the threshold values in the shadow edge detection.

  12. Shadowing: Who Benefits and How? Uncovering a Booming EFL Teaching Technique for Listening Comprehension

    Science.gov (United States)

    Hamada, Yo

    2016-01-01

    This study examines common claims associated with shadowing. Studies in Japan conclude that shadowing is effective for improving learners' listening skills. Two common claims are that shadowing is effective for lower-proficiency learners and that it enhances learners' phoneme perception, thus improving listening comprehension skills. The former…

  13. Compact T-branes

    Science.gov (United States)

    Marchesano, Fernando; Savelli, Raffaele; Schwieger, Sebastian

    2017-09-01

    We analyse global aspects of 7-brane backgrounds with a non-commuting profile for their worldvolume scalars, also known as T-branes. In particular, we consider configurations with no poles and globally well-defined over a compact Kähler surface. We find that such T-branes cannot be constructed on surfaces of positive or vanishing Ricci curvature. For the existing T-branes, we discuss their stability as we move in Kähler moduli space at large volume and provide examples of T-branes splitting into non-mutually-supersymmetric constituents as they cross a stability wall.

  14. Compact synchrotron light sources

    CERN Document Server

    Weihreter, Ernst

    1996-01-01

    This book covers a new niche in circular accelerator design, motivated by the promising industrial prospects of recent micromanufacturing methods - X-ray lithography, synchrotron radiation-based micromachining and microanalysis techniques. It describes the basic concepts and the essential challenges for the development of compact synchrotron radiation sources from an accelerator designer's point of view and gives an outline of the actual state of the art. The volume is intended as an introduction and as a reference for physicists, engineers and managers involved in this rapidly developing fiel

  15. Compact Q-balls

    Energy Technology Data Exchange (ETDEWEB)

    Bazeia, D., E-mail: bazeia@fisica.ufpb.br [Departamento de Física, Universidade Federal da Paraíba, 58051-970 João Pessoa, PB (Brazil); Losano, L.; Marques, M.A. [Departamento de Física, Universidade Federal da Paraíba, 58051-970 João Pessoa, PB (Brazil); Menezes, R. [Departamento de Ciências Exatas, Universidade Federal da Paraíba, 58297-000 Rio Tinto, PB (Brazil); Departamento de Física, Universidade Federal de Campina Grande, 58109-970 Campina Grande, PB (Brazil); Rocha, R. da [Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, 09210-580 Santo André (Brazil)

    2016-07-10

    In this work we deal with non-topological solutions of the Q-ball type in two space–time dimensions, in models described by a single complex scalar field that engenders global symmetry. The main novelty is the presence of stable Q-balls solutions that live in a compact interval of the real line and appear from a family of models controlled by two distinct parameters. We find analytical solutions and study their charge and energy, and show how to control the parameters to make the Q-balls classically and quantum mechanically stable.

  16. Sustainable compact city concept

    Directory of Open Access Journals (Sweden)

    Anja Šulin Košar

    2014-12-01

    Full Text Available The compact city concept has emerged at the end of the 20th century as one of the solutions for sustainable urban development. The concept brings development, which emphasizes urban density, while avoiding urban sprawl. The key features of the concept are mixed land use, construction of higher density (city intensification as well as better access for the entire population and most importantantly, development of the public transport system. The concept has advantages, but also disadvantages, because too much density affects the quality of life in the city.

  17. Shadow-Based Vehicle Detection in Urban Traffic.

    Science.gov (United States)

    Ibarra-Arenado, Manuel; Tjahjadi, Tardi; Pérez-Oria, Juan; Robla-Gómez, Sandra; Jiménez-Avello, Agustín

    2017-04-27

    Vehicle detection is a fundamental task in Forward Collision Avoiding Systems (FACS). Generally, vision-based vehicle detection methods consist of two stages: hypotheses generation and hypotheses verification. In this paper, we focus on the former, presenting a feature-based method for on-road vehicle detection in urban traffic. Hypotheses for vehicle candidates are generated according to the shadow under the vehicles by comparing pixel properties across the vertical intensity gradients caused by shadows on the road, and followed by intensity thresholding and morphological discrimination. Unlike methods that identify the shadow under a vehicle as a road region with intensity smaller than a coarse lower bound of the intensity for road, the thresholding strategy we propose determines a coarse upper bound of the intensity for shadow which reduces false positives rates. The experimental results are promising in terms of detection performance and robustness in day time under different weather conditions and cluttered scenarios to enable validation for the first stage of a complete FACS.

  18. Infrasound propagation in tropospheric ducts and acoustic shadow zones.

    Science.gov (United States)

    de Groot-Hedlin, Catherine D

    2017-10-01

    Numerical computations of the Navier-Stokes equations governing acoustic propagation are performed to investigate infrasound propagation in the troposphere and into acoustic shadow zones. An existing nonlinear finite-difference, time-domain (FDTD) solver that constrains input sound speed models to be axisymmetric is expanded to allow for advection and rigid, stair-step topography. The FDTD solver permits realistic computations along a given azimuth. It is applied to several environmental models to examine the effects of nonlinearity, topography, advection, and two-dimensional (2D) variations in wind and sound speeds on the penetration of infrasound into shadow zones. Synthesized waveforms are compared to a recording of a rocket motor fuel elimination event at the Utah Test and Training Range. Results show good agreement in the amplitude, duration, and spectra of synthesized and recorded waveforms for propagation through 2D atmospheric models whether or not topography, advection, or nonlinearity is explicitly included. However, infrasound propagation through a one-dimensional, range-averaged, atmospheric model yields waveforms with lower amplitudes and frequencies, suggesting that small-scale atmospheric variability causes significant scatter within the troposphere, leading to enhanced infrasound penetration into shadow zones. Thus, unresolved fine-scale atmospheric dynamics are not required to explain infrasound propagation into shadow zones.

  19. On Risk Charges and Shadow Account Options in Pension Funds

    DEFF Research Database (Denmark)

    Jørgensen, Peter Løchte; Gatzert, Nadine

    This paper studies the economic implications of regulatory systems which allow equityholders of pension companies to not only charge a specific premium to compensate them for their higher risk (compared to policyholders), but also to accumulate these risk charges in a so-called shadow account...

  20. On Risk Charges and Shadow Account Options in Pension Funds

    DEFF Research Database (Denmark)

    Jørgensen, Peter Løchte; Gatzert, Nadine

    2015-01-01

    This paper studies the economic implications of regulatory systems which allow equityholders of pension companies to not only charge a specific premium to compensate them for their higher risk (compared to policyholders), but also to accumulate these risk charges in a so-called shadow account...

  1. Overestimation of Mach number due to probe shadow

    Energy Technology Data Exchange (ETDEWEB)

    Gosselin, J. J.; Thakur, S. C.; Tynan, G. R. [Center for Energy Research, University of California at San Diego, San Diego, California 92093 (United States); Sears, S. H. [Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin, 53706 (United States); McKee, J. S.; Scime, E. E. [Department of Physics, West Virginia University, Morgantown, West Virginia 26506 (United States)

    2016-07-15

    Comparisons of the plasma ion flow speed measurements from Mach probes and laser induced fluorescence were performed in the Controlled Shear Decorrelation Experiment. We show the presence of the probe causes a low density geometric shadow downstream of the probe that affects the current density collected by the probe in collisional plasmas if the ion-neutral mean free path is shorter than the probe shadow length, L{sub g} = w{sup 2} V{sub drift}/D{sub ⊥}, resulting in erroneous Mach numbers. We then present a simple correction term that provides the corrected Mach number from probe data when the sound speed, ion-neutral mean free path, and perpendicular diffusion coefficient of the plasma are known. The probe shadow effect must be taken into account whenever the ion-neutral mean free path is on the order of the probe shadow length in linear devices and the open-field line region of fusion devices.

  2. EFFECT OF SHADOWING AND MULTIPATH FADING ON THE ...

    African Journals Online (AJOL)

    The traditional macro-only network have been proved ineffective when communication signal is required for users located in the cell edge and a certain distance away ... Numerical simulation carried out for the macro-femto heterogeneous network using MATLAB shows how the effect of fading and shadowing was reduced.

  3. Physician shadowing by college students: what do patients think?

    Science.gov (United States)

    Bing-You, Robert G; Hayes, Victoria M; Skolfield, Jennifer L

    2014-03-14

    The objective of this study is to determine patients' perceptions of physician shadowing by college students. Thirty-two patients who agreed to have a college student shadow their physician participated in semi-structured interviews during July and August 2013 at two outpatient family medicine centers. Qualitative techniques were utilized to analyze the transcripts of the patient interviews and identify common themes. The majority of patients (78.1%) felt the college student had a neutral effect on their visit and denied having concerns about confidentiality (87.5%). No patient felt that having the college student present affected their ability to maintain a trusting relationship with their physician. Three themes emerged from the qualitative analysis: benefits to students, willing participation and sensitive issues. Most patients (78.5%) recognized that the student was in college or was a premedical student. The overwhelming majority of patients stated that they would have a college student shadow their physician again in the future. Despite concerns raised by other authors about the possible negative effects of physician shadowing by college students, this study shows that patients feel the impact to be primarily neutral and that there are many perceived benefits to both student and patient.

  4. Congress Puts 'Shadow' Pricing Of MS Drugs in the Spotlight.

    Science.gov (United States)

    Silverman, Ed

    2017-10-01

    Lawmakers asked seven companies to explain not only "skyrocketing prices," but a practice known as shadow pricing in which a drugmaker increases the price of an existing medicine to match the price hike or higher price set for a new drug launched by another company.

  5. Perspective: Dynamic Shadowing Growth and its Energy Applications

    Directory of Open Access Journals (Sweden)

    Yiping eZhao

    2014-09-01

    Full Text Available The unique features of dynamic shadowing growth (DSG in structural and compositional design of nanomaterials are discussed. Their recent applications in energy storage, fuel cell, and solar energy conversion have been reviewed briefly. Future directions for applying DSG nanostructures in renewable energy applications are presented.

  6. Assessment of Multipath and Shadowing Effects on UHF Band in ...

    African Journals Online (AJOL)

    Sultan

    3Department of Information and Communication Science, University of florin. Abstract. Ultra-high frequency (UHF) bands are ... Radio propagation, Terrain features. ATBU Journal of Environmental Technology 10, 1, June 2017. Page 2. Assessment of Multipath and Shadowing Effects on UHF Band in Built-Up Environments.

  7. Shadow-Based Vehicle Detection in Urban Traffic

    Directory of Open Access Journals (Sweden)

    Manuel Ibarra-Arenado

    2017-04-01

    Full Text Available Vehicle detection is a fundamental task in Forward Collision Avoiding Systems (FACS. Generally, vision-based vehicle detection methods consist of two stages: hypotheses generation and hypotheses verification. In this paper, we focus on the former, presenting a feature-based method for on-road vehicle detection in urban traffic. Hypotheses for vehicle candidates are generated according to the shadow under the vehicles by comparing pixel properties across the vertical intensity gradients caused by shadows on the road, and followed by intensity thresholding and morphological discrimination. Unlike methods that identify the shadow under a vehicle as a road region with intensity smaller than a coarse lower bound of the intensity for road, the thresholding strategy we propose determines a coarse upper bound of the intensity for shadow which reduces false positives rates. The experimental results are promising in terms of detection performance and robustness in day time under different weather conditions and cluttered scenarios to enable validation for the first stage of a complete FACS.

  8. Shadow Formation at Preschool from a Socio-materiality Perspective

    Science.gov (United States)

    Impedovo, Maria Antonietta; Delserieys-Pedregosa, Alice; Jégou, Corinne; Ravanis, Konstantinos

    2017-06-01

    The paper is set in socio-material farming to offer a way of conceptualising actions and interactions of children in preschool involved in the understanding of scientific concepts. A model of early science education about the physical phenomena of shadow formation is implemented in group work in a French context. The research involved 44 children (13 females and 31 males) of 5-6 years old. The research design was organised in three video recording steps: pre-test, teaching session and post-test. We focus on the analysis of nine teaching sessions to investigate children's `understanding' of shadow formation. A descriptive and qualitative approach was used. In particular, we have identified three main categories (the interaction of the children with the tools, the embodiment and verbal dimension)—with respective indicators—to perform the analysis. From the results, all the categories explored seem to influence each other: all material, human and social dimensions contribute to the children's understanding of shadow formation. Also we have identified some elements that can serve as a potential source of improvement of the teaching session on shadow formation. Finally, the research provides insights on how to improve science activities in preschool with the aim of supporting early understanding of physical phenomena.

  9. Shadow Capital: The Democratization of College Preparatory Education

    Science.gov (United States)

    Cipollone, Kristin; Stich, Amy E.

    2017-01-01

    In this article, we examine the manifestation and consequences of shadow capital within two public, urban, nonselective, college preparatory-designated high schools serving exclusively nondominant students. Informed by three years of ethnographic data, we argue that the transference of a historically elite college preparatory education from…

  10. Nuclear reactor shield including magnesium oxide

    Science.gov (United States)

    Rouse, Carl A.; Simnad, Massoud T.

    1981-01-01

    An improvement in nuclear reactor shielding of a type used in reactor applications involving significant amounts of fast neutron flux, the reactor shielding including means providing structural support, neutron moderator material, neutron absorber material and other components as described below, wherein at least a portion of the neutron moderator material is magnesium in the form of magnesium oxide either alone or in combination with other moderator materials such as graphite and iron.

  11. Heat shielding: a task for youngsters

    OpenAIRE

    Starks, Philip T.; Johnson, Rebecca N.; Adam J. Siegel; Meridith M. Decelle

    2005-01-01

    Heat shielding is a recently identified mechanism used by worker honey bees (Apis mellifera) to help maintain constant hive temperatures. Only workers perform this behavior; in our experiment, drones actively avoided heated hive regions. Observations of marked day-old cohorts within broodcomb regions indicate that heat shielding is performed by young bees to preferentially protect advanced stage larvae and pupae. As expected, the number of heat-shielders significantly increased with both the ...

  12. In-beam background suppression shield

    DEFF Research Database (Denmark)

    Santoro, V.; Cai, Xiao Xiao; DiJulio, D. D.

    2015-01-01

    , which do not use a bender to help mitigate the fast neutron background, are the most challenging. For these beam lines we propose the innovative shielding of placing blocks of material directly into the guide system, which allow a minimum attenuation of the cold and thermal fluxes relative...... to the background suppression. This shielding configuration has been worked into a beam line model using Geant4. We study particularly the advantages of single crystal sapphire and silicon blocks....

  13. SU-E-T-548: Modeling of Breast IORT Using the Xoft 50 KV Brachytherapy Source and 316L Steel Rigid Shield

    Energy Technology Data Exchange (ETDEWEB)

    Burnside, W [Mountain View, CA (United States)

    2015-06-15

    Purpose: Xoft provides a set of 316L Stainless Steel Rigid Shields to be used with their 50 kV X-ray source for Breast IORT treatments. Modeling the different shield sizes in MCNP provides information to help make clinical decisions for selecting the appropriate shield size. Methods: The Xoft Axxent 50 kV Electronic Brachytherapy System has several applications in radiation therapy, one of which is treating cancer of the breast intraoperatively by placing the miniaturized X-ray tube inside an applicator balloon that is expanded to fill the lumpectomy bed immediately following tumor removal. The ribs, lung, and muscular chest wall are all regions at risk to receive undesired dose during the treatment. A Xoft 316L Stainless Steel Rigid Shield can be placed between the intracostal muscles of the chest wall and the remaining breast tissue near the balloon to attenuate the beam and protect these organs. These shields are provided in 5 different sizes, and the effects on dose to the surrounding tissues vary with shield size. MCNP was used to model this environment and tally dose rate to certain regions of interest. Results: The average rib dose rate calculated using 0cm (i.e., no shield), 3cm, and 5cm diameter shields were 26.89, 15.43, and 8.91 Gy/hr respectively. The maximum dose rates within the rib reached 94.74 Gy/hr, 53.56 Gy/hr, and 31.44 Gy/hr for the 0cm, 3cm, and 5cm cases respectively. The shadowing effect caused by the steel shields was seen in the 3-D meshes and line profiles. Conclusion: This model predicts a higher dose rate to the underlying rib region with the 3cm shield compared to the 5cm shield; it may be useful to select the largest possible diameter when choosing a shield size for a particular IORT patient. The ability to attenuate the beam to reduce rib dose was also confirmed. Research sponsored by Xoft Inc, a subsidiary of iCAD.

  14. Experimental evaluation of plasticity-induced crack shielding from crack tip displacements fields

    Directory of Open Access Journals (Sweden)

    J.M. Vasco-Olmo

    2015-07-01

    Full Text Available In this work it is proposed a methodology for the evaluation of plasticity-induced crack shielding from the analysis of the crack tip displacements fields measured by digital image correlation. This methodology is based on the evaluation of the stress intensity factors determined from the displacements fields measured at the vicinity of the tip of a growing fatigue crack. For the characterisation of the crack tip displacements field, CJP model has been implemented. This model considers the shielding effects due to plasticity generated during fatigue crack growth. For the purpose of the current work, several fatigue experiments at different R-ratios have been conducted on Al2024-T3 compact tension specimens. In addition, compliance based methods have been adopted to perform a comparison of the results with those obtained by DIC. Results show a good level of agreement, illustrating the enormous potential of DIC technique for the study of fracture mechanics problems.

  15. Compaction of Titanium Powders

    Energy Technology Data Exchange (ETDEWEB)

    Stephen J. Gerdemann; Paul D. Jablonski

    2010-11-01

    Accurate modeling of powder densification has been an area of active research for more than 60 years. The earliest efforts were focused on linearization of the data because computers were not readily available to assist with curve-fitting methods. In this work, eight different titanium powders (three different sizes of sponge fines <150 μm, <75 μm, and < 45 μm; two different sizes of a hydride-dehydride [HDH] <75 μm and < 45 μm; an atomized powder; a commercially pure [CP] Ti powder from International Titanium Powder [ITP]; and a Ti 6 4 alloy powder) were cold pressed in a single-acting die instrumented to collect stress and deformation data during compaction. From these data, the density of each compact was calculated and then plotted as a function of pressure. The results show that densification of all the powders, regardless of particle size, shape, or chemistry, can be modeled accurately as the sum of an initial density plus the sum of a rearrangement term and a work-hardening term. These last two terms are found to be a function of applied pressure and take the form of an exponential rise.

  16. Compaction of Titanium Powders

    Energy Technology Data Exchange (ETDEWEB)

    Gerdemann, Stephen,J; Jablonski, Paul, J

    2011-05-01

    Accurate modeling of powder densification has been an area of active research for more than 60 years. The earliest efforts were focused on linearization of the data because computers were not readily available to assist with curve-fitting methods. In this work, eight different titanium powders (three different sizes of sponge fines<150 {micro}m,<75 {micro}m, and<45 {micro}m; two different sizes of a hydride-dehydride [HDH]<75 {micro}m and<45 {micro}m; an atomized powder; a commercially pure [CP] Ti powder from International Titanium Powder [ITP]; and a Ti 6 4 alloy powder) were cold pressed in a single-acting die instrumented to collect stress and deformation data during compaction. From these data, the density of each compact was calculated and then plotted as a function of pressure. The results show that densification of all the powders, regardless of particle size, shape, or chemistry, can be modeled accurately as the sum of an initial density plus the sum of a rearrangement term and a work-hardening term. These last two terms are found to be a function of applied pressure and take the form of an exponential rise.

  17. The Shadow Knows: Using Shadows to Investigate the Structure of the Pretransitional Disk of HD 100453

    Energy Technology Data Exchange (ETDEWEB)

    Long, Zachary C.; Fernandes, Rachel B.; Sitko, Michael [Department of Physics, University of Cincinnati, Cincinnati, OH 45221 (United States); Wagner, Kevin [Department of Astronomy/Steward Observatory, The University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Muto, Takayuki [Division of Liberal Arts, Kogakuin University, 1-24-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo, 163-8677 (Japan); Hashimoto, Jun; Oh, Daehyon; Tamura, Motohide; Yang, Yi [National Astronomical Observatory of Japan, 2-21-1, Osawa, Mitaka, Tokyo, 181-8588 (Japan); Follette, Katherine [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA 94305 (United States); Grady, Carol A. [Eureka Scientific, 2452 Delmer Street, Suite 100, Oakland CA 96402 (United States); Fukagawa, Misato [Division of Particle and Astrophysical Science, Graduate School of Science, Nagoya University, Nagoya (Japan); Hasegawa, Yasuhiro [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Kluska, Jacques; Kraus, Stefan [University of Exeter Astrophysics Group, School of Physics, Stocker Road, Exeter, Devon EX4 4QL (United Kingdom); Mayama, Satoshi [Department of Astronomical Science, The Graduate University for Advanced Studies (SOKENDAI), Shonan Village, Hayama, Kanagawa 240-0193 (Japan); McElwain, Michael W. [Exoplanets and Stellar Astrophysics Laboratory, Code 667, NASA’s Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Uyama, Taichi [Department of Astronomy and RESCUE, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033 (Japan); Wisniewski, John P. [Homer L. Dodge Department of Physics, University of Oklahoma, Norman, OK 73071 (United States)

    2017-03-20

    We present Gemini Planet Imager polarized intensity imagery of HD 100453 in Y , J , and K 1 bands that reveals an inner gap (9–18 au), an outer disk (18–39 au) with two prominent spiral arms, and two azimuthally localized dark features that are also present in Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) total intensity images. Spectral energy distribution fitting further suggests that the radial gap extends to 1 au. The narrow, wedge-like shape of the dark features appears similar to predictions of shadows cast by an inner disk that is misaligned with respect to the outer disk. Using the Monte Carlo radiative transfer code HOCHUNCK3D, we construct a model of the disk that allows us to determine its physical properties in more detail. From the angular separation of the features, we measure the difference in inclination between the disks (45°) and their major axes, PA = 140° east of north for the outer disk, and 100° for the inner disk. We find an outer-disk inclination of 25° ± 10° from face-on, in broad agreement with the Wagner et al. measurement of 34°. SPHERE data in J and H bands indicate a reddish disk, which indicates that HD 100453 is evolving into a young debris disk.

  18. Numerical Models for the Study of Electromagnetic Shielding

    Directory of Open Access Journals (Sweden)

    POPA Monica

    2012-10-01

    Full Text Available The paper presents 2D and 3D models for the study of electromagnetic shielding of a coil. The magnetic fields are computed for defining the shielding effectiveness. Parametrized numerical studies were performed in order to established the influence of shield thickness and height on magnetic field in certain points located in the exterior of coil – shield setup and on induced power within the shield.

  19. Isometric coactions of compact quantum groups on compact ...

    Indian Academy of Sciences (India)

    We propose a notion of isometric coaction of a compact quantum group on a compact quantum metric space in the framework of Rieffel, where the metric structure is given by a Lipnorm. Within this setting we study the problem of the existence of a quantum isometry group.

  20. Leave-one-out Kernel Optimization for Shadow Detection and Removal.

    Science.gov (United States)

    Yago Vicente, Tomas F; Hoai, Minh; Samaras, Dimitris

    2017-04-06

    The objective of this work is to detect shadows in images. We pose this as the problem of labeling image regions, where each region corresponds to a group of superpixels. To predict the label of each region, we train a kernel Least-Squares Support Vector Machine(LSSVM) for separating shadow and non-shadow regions. The parameters of the kernel and the classifier are jointly learned to minimize the leave-one-out cross validation error. Optimizing the leave-one-out cross validation error is typically difficult, but it can be done efficiently in our framework. Experiments on two challenging shadow datasets, UCF and UIUC, show that our region classifier outperforms more complex methods. We further enhance the performance of the region classifier by embedding it in a Markov Random Field(MRF) framework and adding pairwise contextual cues. This leads to a method that outperforms the state-of-the-art for shadow detection. In addition we propose a new method for shadow removal based on region relighting. For each shadow region we use a trained classifier to identify a neighboring lit region of the same material. Given a pair of lit-shadow regions we perform a region relighting transformation based on histogram matching of luminance values between the shadow region and the lit region. Once a shadow is detected, we demonstrate that our shadow removal approach produces results that outperform the state of the art by evaluating our method using a publicly available benchmark dataset.

  1. Shadow Detection Based on Regions of Light Sources for Object Extraction in Nighttime Video.

    Science.gov (United States)

    Lee, Gil-Beom; Lee, Myeong-Jin; Lee, Woo-Kyung; Park, Joo-Heon; Kim, Tae-Hwan

    2017-03-22

    Intelligent video surveillance systems detect pre-configured surveillance events through background modeling, foreground and object extraction, object tracking, and event detection. Shadow regions inside video frames sometimes appear as foreground objects, interfere with ensuing processes, and finally degrade the event detection performance of the systems. Conventional studies have mostly used intensity, color, texture, and geometric information to perform shadow detection in daytime video, but these methods lack the capability of removing shadows in nighttime video. In this paper, a novel shadow detection algorithm for nighttime video is proposed; this algorithm partitions each foreground object based on the object's vertical histogram and screens out shadow objects by validating their orientations heading toward regions of light sources. From the experimental results, it can be seen that the proposed algorithm shows more than 93.8% shadow removal and 89.9% object extraction rates for nighttime video sequences, and the algorithm outperforms conventional shadow removal algorithms designed for daytime videos.

  2. Shadow casted by a Konoplya-Zhidenko rotating non-Kerr black hole

    Science.gov (United States)

    Wang, Mingzhi; Chen, Songbai; Jing, Jiliang

    2017-10-01

    We have investigated the shadow of a Konoplya-Zhidenko rotating non-Kerr black hole with an extra deformation parameter. The spacetime structure arising from the deformed parameter affects sharply the black hole shadow. With the increase of the deformation parameter, the size of the shadow of black hole increase and its shape becomes more rounded for arbitrary rotation parameter. The D-shape shadow of black hole emerges only in the case ablack hole shadow possesses a cusp shape with small eye lashes in the cases with a>M, and the shadow becomes less cuspidal with the increase of the deformation parameter. Our result show that the presence of the deformation parameter yields a series of significant patterns for the shadow casted by a Konoplya-Zhidenko rotating non-Kerr black hole.

  3. Determinants of the Shadow Economy in the Czech Regions: A Region-Level Study

    Directory of Open Access Journals (Sweden)

    Buček Jakub

    2017-09-01

    Full Text Available This paper investigates the size and development of the shadow economy in the Czech Republic on the state-level base over the 2005-2014 period. The multiple indicators multiple causes (MIMIC model is used to assess the estimation of the shadow economy size. I investigate how labour market, number of people with at least one distraint, and the burden of taxation might contribute to the existence of the shadow economy. While the former two are important determinants of the shadow economy, I find no evidence to prove any significant impact of distraints on the shadow economy size. As for the country’s particular regions, I find that those surrounding big cities, especially Prague, have, on average, a smaller shadow economy size, whereas regions in the borderlands (former Sudetenland suffer from a larger shadow economy.

  4. Shadow of a Kerr-Sen dilaton-axion Black Hole

    CERN Document Server

    Dastan, Sara; Soroushfar, Saheb

    2016-01-01

    We analyze the shadow of charged stationary axially symmetric space-time (Kerr-Sen dilaton-axion black hole). This black hole is defined by a mass $M$, a spin $a$ and $r_{\\alpha}=Q^{2}/M$, where $Q$ is the electric charge. Shadows are investigated in two conditions, i) for an observer at infinity in vacuum and ii) for an observer at infinity in the presence of plasma with radial power-low density. In vacuum, the shadow of this black hole depends on charge and spin parameter. We can see that, increasing electric charge, $Q$ decreases the size of shadow. Also, increasing spin parameter $a$ decreases the size of shadow. However, in existence of plasma, parameter of plasma like refraction index, $n$, playing an important role on shadows. In fact, decreasing refraction index decreases the size of shadow.

  5. A Soft Shadow Detection Method Based on MRF for Remote Sensing Images

    Directory of Open Access Journals (Sweden)

    Pengwei Li

    2015-01-01

    Full Text Available Shadows limit many remote sensing applications such as classification, target detection, and change detection. Most current shadow detection methods utilize the histogram threshold of spectral characteristics to distinguish the shadows and nonshadows directly, called “hard binary shadow.” Obviously, the performance of threshold-based methods heavily rely on the selected threshold. Simultaneously, these threshold-based methods do not take any spatial information into account. To overcome these shortcomings, a soft shadow description method is developed by introducing the concept of opacity into shadow detection, and MRF-based shadow detection method is proposed in order to make use of neighborhood information. Experiments on remote sensing images have shown that the proposed method can obtain more accurate detection results.

  6. Can active proton interrogation find shielded nuclear threats at human-safe radiation levels?

    Energy Technology Data Exchange (ETDEWEB)

    Liew, Seth Van, E-mail: vanliew@gmail.com

    2017-05-21

    A new method of low-dose proton radiography is presented. The system is composed of an 800 MeV proton source, bending magnets, and compact detectors, and is designed for drive-through cargo scanning. The system has been simulated using GEANT4. Material identification algorithms and pixel sorting methods are presented that allow the system to perform imaging at doses low enough to scan passenger vehicles and people. Results are presented on imaging efficacy of various materials and cluttered cargoes. The identification of shielded nuclear materials at human-safe doses has been demonstrated.

  7. The Nano-X Linear Accelerator: A Compact and Economical Cancer Radiotherapy System Incorporating Patient Rotation.

    Science.gov (United States)

    Eslick, Enid M; Keall, Paul J

    2015-10-01

    Rapid technological improvements in radiotherapy delivery results in improved outcomes to patients, yet current commercial systems with these technologies on board are costly. The aim of this study was to develop a state-of-the-art cancer radiotherapy system that is economical and space efficient fitting with current world demands. The Nano-X system is a compact design that is light weight combining a patient rotation system with a vertical 6 MV fixed beam. In this paper, we present the Nano-X system design configuration, an estimate of the system dimensions and its potential impact on shielding cost reductions. We provide an assessment of implementing such a radiotherapy system clinically, its advantages and disadvantages compared to a compact conventional gantry rotating linac. The Nano-X system has several differentiating features from current radiotherapy systems, it is [1] compact and therefore can fit into small vaults, [2] light weight, and [3] engineering efficient, i.e., it rotates a relatively light component and the main treatment delivery components are not under rotation (e.g., DMLCs). All these features can have an impact on reducing the costs of the system. In terms of shielding requirements, leakage radiation was found to be the dominant contributor to the Nano-X vault and as such no primary shielding was necessary. For a low leakage design, the Nano-X vault footprint and concrete volume required is 17 m2 and 35 m3 respectively, compared to 54 m2 and 102 m3 for a conventional compact linac vault, resulting in decreased costs in shielding. Key issues to be investigated in future work are the possible patient comfort concerns associated with the patient rotation system, as well as the magnitude of deformation and subsequent adaptation requirements. © The Author(s) 2014.

  8. Compact semiconductor lasers

    CERN Document Server

    Yu, Siyuan; Lourtioz, Jean-Michel

    2014-01-01

    This book brings together in a single volume a unique contribution by the top experts around the world in the field of compact semiconductor lasers to provide a comprehensive description and analysis of the current status as well as future directions in the field of micro- and nano-scale semiconductor lasers. It is organized according to the various forms of micro- or nano-laser cavity configurations with each chapter discussing key technical issues, including semiconductor carrier recombination processes and optical gain dynamics, photonic confinement behavior and output coupling mechanisms, carrier transport considerations relevant to the injection process, and emission mode control. Required reading for those working in and researching the area of semiconductors lasers and micro-electronics.

  9. Compact photonic spin filters

    Science.gov (United States)

    Ke, Yougang; Liu, Zhenxing; Liu, Yachao; Zhou, Junxiao; Shu, Weixing; Luo, Hailu; Wen, Shuangchun

    2016-10-01

    In this letter, we propose and experimentally demonstrate a compact photonic spin filter formed by integrating a Pancharatnam-Berry phase lens (focal length of ±f ) into a conventional plano-concave lens (focal length of -f). By choosing the input port of the filter, photons with a desired spin state, such as the right-handed component or the left-handed one, propagate alone its original propagation direction, while the unwanted spin component is quickly diverged after passing through the filter. One application of the filter, sorting the spin-dependent components of vector vortex beams on higher-order Poincaré sphere, is also demonstrated. Our scheme provides a simple method to manipulate light, and thereby enables potential applications for photonic devices.

  10. CIM - compact intensity modulation.

    Energy Technology Data Exchange (ETDEWEB)

    Bleuel, M.; Lang, E.; Gahler, G.; Lal, J.; Intense Pulsed Neutron Source; Inst. Lau Langevin

    2008-07-21

    Compact intensity modulation (CIM), a new method to modulate the intensity of a neutron beam is demonstrated. CIM allows the production of arbitrary signals where the focus point can be chosen and changed without any constraints. A novel feature in this technique compared to spin echo techniques is that the neutron polarization is kept parallel or anti-parallel to the static fields during the passage through the magnetic fields and the beating pattern at the detector is produced by an amplitude modulation (AM) of the adiabatic RF-spin flippers rather than Larmor precession like in neutron spin echo (NSE) instruments; thus, the achievable contrast is very high and the instrument resolution can be changed very quickly. This gives the fascinating possibility at pulsed neutron sources to sweep the modulation frequency of the flippers in order to increase dynamic resolution range during the same neutron pulse.

  11. Compact Neutrino Source

    CERN Document Server

    LoSecco, John

    2015-01-01

    Some evidence for sterile neutrinos has been found in short baseline observations where the measured neutrino flux did not agree with expectations. Systematic uncertainties from the expected values has limited the sensitivity of this approach. Observation at multiple distances can remove the normalization uncertainty by isolating the distance dependence. This doesn't work for high $\\Delta m^{2}$ sterile neutrinos since they are fully mixed at most observation distances and only shift the normalization of the flux. A compact intense source of neutrinos based on a subcritical fission reactor would permit observation of oscillations on submeter distance scales and clearly distinguish between a systematic normalization and the $L/E$ dependence expected from oscillations.

  12. Riddles in the Dark: Imaging Inside Mercury's Permanently Shadowed Craters

    Science.gov (United States)

    Ernst, C. M.; Chabot, N. L.; Denevi, B. W.; Nair, H.; Deutsch, A. N.; Murchie, S. L.; Robinson, M. S.; Blewett, D. T.; Head, J. W.; Harmon, J. K.; Neumann, G. A.; Solomon, S. C.

    2013-12-01

    Numerous lines of evidence independently point to the presence of water ice in Mercury's polar regions: Earth-based radar shows radar-bright regions; Mariner 10 and MESSENGER Mercury Dual Imaging System (MDIS) images reveal that these regions are permanently (south polar region) or persistently (north polar region) shadowed; neutron spectrometry indicates hydrogen-rich material; thermal models support the presence of water ice; and Mercury Laser Altimeter (MLA) reflectance measurements at 1064 nm show high and low reflectance deposits consistent in location to where models predict surface and buried water ice, respectively. Throughout 2013, MESSENGER executed a campaign dedicated to imaging the permanently shadowed crater floors of Mercury's north polar region using sunlight scattered from nearby terrain. The campaign makes use of the broadband clear filter (central wavelength 700 nm, bandwidth 600 nm) of the MDIS wide-angle camera (WAC) to target and image radar-bright areas within all host craters > 10 km in diameter under multiple lighting conditions. To date, MESSENGER has imaged the interiors of nearly 20 craters that host radar-bright deposits, including the largest such deposits near the north pole that are likely to host surface water ice. The images reveal a variety of surface morphologies, ranging from the smooth crater floor of the fresh Kandinsky crater, to the moderately cratered floor of Tolkien crater, and to the battered floor of Prokofiev crater, in which the permanently shadowed region does not differ morphologically from the rest of the crater floor. Thus, no distinct morphology is identified in association with polar deposits, and craters hosting such material span the typical range of degradation states relative to their illuminated counterparts. MDIS images also reveal albedo differences in craters with floors not fully in permanent shadow. Prokofiev provides a special environment for viewing a radar- and MLA-bright region suspected to host

  13. Shielding Structures for Interplanetary Human Mission

    Science.gov (United States)

    Tracino, Emanuele; Lobascio, Cesare

    2012-07-01

    Since the end of Apollo missions, human spaceflight has been limited to the Low Earth Orbit (LEO), inside the protective magnetic field of the Earth, because astronauts are, to the largest degree, protected from the harsh radiation environment of the interplanetary space. However, this situation will change when space exploration missions beyond LEO will become the real challenge of the human exploration program. The feasibility of these missions in the solar system is thus strongly connected to the capability to mitigate the radiation-induced biological effects on the crew during the journey and the permanence on the intended planet surface. Inside the International Space Station (ISS), the volumes in which the crew spends most of the time, namely the crew quarters are the only parts that implement dedicated additional radiation shielding made of polyethylene tiles designed for mitigating SPE effects. Furthermore, specific radiation shielding materials are often added to the described configuration to shield crew quarters or the entire habitat example of these materials are polyethylene, liquid hydrogen, etc. but, increasing the size of the exploration vehicles to bring humans beyond LEO, and without the magnetosphere protection, such approach is unsustainable because the mass involved is a huge limiting factor with the actual launcher engine technology. Moreover, shielding against GCR with materials that have a low probability of nuclear interactions and in parallel a high ionizing energy loss is not always the best solution. In particular there is the risk to increase the LET of ions arriving at the spacecraft shell, increasing their Radio-Biological Effectiveness. Besides, the production of secondary nuclei by projectile and target fragmentation is an important issue when performing an engineering assessment of materials to be used for radiation shielding. The goal of this work is to analyze different shielding solutions to increase as much as possible the

  14. Analytic Ballistic Performance Model of Whipple Shields

    Science.gov (United States)

    Miller, J. E.; Bjorkman, M. D.; Christiansen, E. L.; Ryan, S. J.

    2015-01-01

    The dual-wall, Whipple shield is the shield of choice for lightweight, long-duration flight. The shield uses an initial sacrificial wall to initiate fragmentation and melt an impacting threat that expands over a void before hitting a subsequent shield wall of a critical component. The key parameters to this type of shield are the rear wall and its mass which stops the debris, as well as the minimum shock wave strength generated by the threat particle impact of the sacrificial wall and the amount of room that is available for expansion. Ensuring the shock wave strength is sufficiently high to achieve large scale fragmentation/melt of the threat particle enables the expansion of the threat and reduces the momentum flux of the debris on the rear wall. Three key factors in the shock wave strength achieved are the thickness of the sacrificial wall relative to the characteristic dimension of the impacting particle, the density and material cohesion contrast of the sacrificial wall relative to the threat particle and the impact speed. The mass of the rear wall and the sacrificial wall are desirable to minimize for launch costs making it important to have an understanding of the effects of density contrast and impact speed. An analytic model is developed here, to describe the influence of these three key factors. In addition this paper develops a description of a fourth key parameter related to fragmentation and its role in establishing the onset of projectile expansion.

  15. Hydrogen Induced Cracking of Drip Shield

    Energy Technology Data Exchange (ETDEWEB)

    G. De

    2003-02-24

    One potential failure mechanism for titanium and its alloys under repository conditions is via the absorption of atomic hydrogen in the metal crystal lattice. The resulting decreased ductility and fracture toughness may lead to brittle mechanical fracture called hydrogen-induced cracking (HIC) or hydrogen embrittlement. For the current design of the engineered barrier without backfill, HIC may be a problem since the titanium drip shield can be galvanically coupled to rock bolts (or wire mesh), which may fall onto the drip shield, thereby creating conditions for hydrogen production by electrochemical reaction. The purpose of this scientific analysis and modeling activity is to evaluate whether the drip shield will fail by HIC or not under repository conditions within 10,000 years of emplacement. This Analysis and Model Report (AMR) addresses features, events, and processes related to hydrogen induced cracking of the drip shield. REV 00 of this AMR served as a feed to ''Waste Package Degradation Process Model Report'' and was developed in accordance with the activity section ''Hydrogen Induced Cracking of Drip Shield'' of the development plan entitled ''Analysis and Model Reports to Support Waste Package PMR'' (CRWMS M&O 1999a). This AMR, prepared according to ''Technical Work Plan for: Waste Package Materials Data Analyses and Modeling'' (BSC 2002), is to feed the License Application.

  16. Roller-compacted concrete pavements.

    Science.gov (United States)

    2010-09-01

    Roller-compacted concrete (RCC) gets its name from the heavy vibratory steel drum and rubber-tired rollers used to help compact it into its final form. RCC has similar strength properties and consists of the same basic ingredients as conventional con...

  17. Compaction of alpha contaminated wastes

    Energy Technology Data Exchange (ETDEWEB)

    Herald, W.R.; Luthy, D.F.

    1976-01-30

    The initial equipment installation and development of procedures for compacting less than or equal to 10 nCi/gram waste, greater than or equal to 10 nCi/gram waste, and less than or equal to 100 nCi/gram waste are given. Design and construction of the new compaction facility is discussed. (LK)

  18. Analysis of Shield Construction in Spherical Weathered Granite Development Area

    Science.gov (United States)

    Cao, Quan; Li, Peigang; Gong, Shuhua

    2018-01-01

    The distribution of spherical weathered bodies (commonly known as "boulder") in the granite development area directly affects the shield construction of urban rail transit engineering. This paper is based on the case of shield construction of granite globular development area in Southern China area, the parameter control in shield machine selection and shield advancing during the shield tunneling in this special geological environment is analyzed. And it is suggested that shield machine should be selected for shield construction of granite spherical weathered zone. Driving speed, cutter torque, shield machine thrust, the amount of penetration and the speed of the cutter head of shield machine should be controlled when driving the boulder formation, in order to achieve smooth excavation and reduce the disturbance to the formation.

  19. Shadow Areas Robust Matching Among Image Sequence in Planetary Landing

    Science.gov (United States)

    Ruoyan, Wei; Xiaogang, Ruan; Naigong, Yu; Xiaoqing, Zhu; Jia, Lin

    2017-01-01

    In this paper, an approach for robust matching shadow areas in autonomous visual navigation and planetary landing is proposed. The approach begins with detecting shadow areas, which are extracted by Maximally Stable Extremal Regions (MSER). Then, an affine normalization algorithm is applied to normalize the areas. Thirdly, a descriptor called Multiple Angles-SIFT (MA-SIFT) that coming from SIFT is proposed, the descriptor can extract more features of an area. Finally, for eliminating the influence of outliers, a method of improved RANSAC based on Skinner Operation Condition is proposed to extract inliers. At last, series of experiments are conducted to test the performance of the approach this paper proposed, the results show that the approach can maintain the matching accuracy at a high level even the differences among the images are obvious with no attitude measurements supplied.

  20. Wake models developed during the Wind Shadow project

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, S.; Ott, S.; Pena, A.; Berg, J.; Nielsen, M.; Rathmann, O.; Joergensen, H.

    2011-11-15

    The Wind Shadow project has developed and validated improved models for determining the wakes losses, and thereby the array efficiency of very large, closely packed wind farms. The rationale behind the project has been that the existing software has been covering these types of wind farms poorly, both with respect to the densely packed turbines and the large fetches needed to describe the collective shadow effects of one farm to the next. Further the project has developed the necessary software for the use of the models. Guidelines with recommendations for the use of the models are included in the model deliverables. The project has been carried out as a collaborative project between Risoe DTU, DONG, Vattenfall, DNV and VESTAS, and it has been financed by energinet.dk grant no. 10086. (Author)

  1. Electromagnetic Shielding Efficiency Measurement of Composite Materials

    Science.gov (United States)

    Dřínovský, J.; Kejík, Z.

    2009-01-01

    This paper deals with the theoretical and practical aspects of the shielding efficiency measurements of construction composite materials. This contribution describes an alternative test method of these measurements by using the measurement circular flange. The measured results and parameters of coaxial test flange are also discussed. The measurement circular flange is described by measured scattering parameters in the frequency range from 9 kHz up to 1 GHz. The accuracy of the used shielding efficiency measurement method was checked by brass calibration ring. The suitability of the coaxial test setup was also checked by measurements on the EMC test chamber. This data was compared with the measured data on the real EMC chamber. The whole measurement of shielding efficiency was controlled by the program which runs on a personal computer. This program was created in the VEE Pro environment produced by © Agilent Technology.

  2. Accelerator shielding experts meet at CERN

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    Fifteen years after its first CERN edition, the Shielding Aspects of Accelerator, Targets and Irradiation Facility (SATIF) conference was held again here from 2-4 June. Now at its 10th edition, SATIF10 brought together experts from all over the world to discuss issues related to the shielding techniques. They set out the scene for an improved collaboration and discussed novel shielding solutions.   This was the most attended meeting of the series with more than 65 participants from 34 institutions and 14 countries. “We welcomed experts from many different laboratories around the world. We come from different contexts but we face similar problems. In this year’s session, among other things, we discussed ways for improving the effectiveness of calculations versus real data, as well as experimental solutions to investigate the damage that radiation produces on various materials and the electronics”, says Marco Silari, Chair of the conference and member of the DGS/RP gro...

  3. Progress of the ITER Thermal Shields

    Energy Technology Data Exchange (ETDEWEB)

    Her, Namil, E-mail: namil.her@iter.org [ITER Organisation, Route de Vinon-sur-Verdon – CS 90046, 13067 St Paul-lez-Durance Cedex (France); Hick, Robby; Le Barbier, Robin; Arzoumanian, Terenig; Choi, Chang-Ho; Sborchia, Carlo [ITER Organisation, Route de Vinon-sur-Verdon – CS 90046, 13067 St Paul-lez-Durance Cedex (France); Chung, Wooho; Nam, Kwanwoo; Noh, Chang Hyun; Kang, Dong Kwon; Kang, Gyoung-O. [ITER Korea, National Fusion Research Institute, Daejeon 34133 (Korea, Republic of); Kang, Youngkil; Lim, Kisuk [SFA Engineering Corporation, Hwaseong-si, Gyeonggi-do 10060 (Korea, Republic of)

    2016-11-01

    Highlights: • Design improvement of the ITER Thermal Shields was introduced. • Design of TS manifold and TS instrumentation were summarized. • Produced main material of the TS (SS304LN) was summarized. • Status of the VVTS manufacturing and the inspection requirements were summarized. - Abstract: The role of the ITER Thermal Shields (TS) is to minimize the radiation heat load from the warm components such as vacuum vessel and cryostat to magnet operating at 4.5 K. The final design of TS was completed in 2013 and manufacturing of the vacuum vessel thermal shield (VVTS) is now on-going. This paper describes the development status of the TS in particular the design improvements, the fabrication and the requirements.

  4. Andrew Beatty, A shadow falls; In the heart of Java.

    OpenAIRE

    Andrew Beatty; Edwin Wieringa; Michael Peletz; Pujo Semedi

    2010-01-01

    In this feature we highlight a recently launched book. We invite specialists in the field to comment on the book, and we invite the author to respond to their comments. In this issue we focus on Andrew Beatty's, A shadow falls; In the heart of Java. Those invited to comment on the book are Puja Semedi, Michael Peletz and Edwin Wieiringa. Registered readers may participate in the debate.

  5. Andrew Beatty, A shadow falls; In the heart of Java.

    Directory of Open Access Journals (Sweden)

    Andrew Beatty

    2010-09-01

    Full Text Available In this feature we highlight a recently launched book. We invite specialists in the field to comment on the book, and we invite the author to respond to their comments. In this issue we focus on Andrew Beatty's, A shadow falls; In the heart of Java. Those invited to comment on the book are Puja Semedi, Michael Peletz and Edwin Wieiringa. Registered readers may participate in the debate.

  6. We Three (My echo, my shadow and me)

    OpenAIRE

    Veator, Valerie E.

    2015-01-01

    We Three (My echo, my shadow and me) presents a tripartite work that exercises forms of tracing, imbedding, concealing and revealing across painting, video, and installation. Inspired by Jacques Rivette’s 1974 film Celine and Julie Go Boating, We Three examines perception and subjectivity in today’s screenic culture. We Three draws out modes transference in the form of an echoed, displaced transmission as it exists within and between specific artworks. The three parts are installed as echoes ...

  7. Shadow Banking – Developments in Times of Financial Crisis

    Directory of Open Access Journals (Sweden)

    Bogdan Munteanu

    2016-01-01

    The paper considers the following entities and activities, without limitation to or completenessof viewpoints: finance companies, asset backed financial instruments, structured investments,financing vehicles, money market funds, asset managers, credit hedge funds and venture capital,providing characteristics of shadow banking and their economic functions relative to the classicbanking system, as they pose a systemic risk due to asymmetric information and gaps created inmatching liquidity tenures with duration, by using synthetic leverage finance.

  8. Self-Shielding Of Transmission Lines

    Energy Technology Data Exchange (ETDEWEB)

    Christodoulou, Christos [Univ. of New Mexico, Albuquerque, NM (United States)

    2017-03-01

    The use of shielding to contend with noise or harmful EMI/EMR energy is not a new concept. An inevitable trade that must be made for shielding is physical space and weight. Space was often not as much of a painful design trade in older larger systems as they are in today’s smaller systems. Today we are packing in an exponentially growing number of functionality within the same or smaller volumes. As systems become smaller and space within systems become more restricted, the implementation of shielding becomes more problematic. Often, space that was used to design a more mechanically robust component must be used for shielding. As the system gets smaller and space is at more of a premium, the trades starts to result in defects, designs with inadequate margin in other performance areas, and designs that are sensitive to manufacturing variability. With these challenges in mind, it would be ideal to maximize attenuation of harmful fields as they inevitably couple onto transmission lines without the use of traditional shielding. Dr. Tom Van Doren proposed a design concept for transmission lines to a class of engineers while visiting New Mexico. This design concept works by maximizing Electric field (E) and Magnetic Field (H) field containment between operating transmission lines to achieve what he called “Self-Shielding”. By making the geometric centroid of the outgoing current coincident with the return current, maximum field containment is achieved. The reciprocal should be true as well, resulting in greater attenuation of incident fields. Figure’s 1(a)-1(b) are examples of designs where the current centroids are coincident. Coax cables are good examples of transmission lines with co-located centroids but they demonstrate excellent field attenuation for other reasons and can’t be used to test this design concept. Figure 1(b) is a flex circuit design that demonstrate the implementation of self-shielding vs a standard conductor layout.

  9. SHADOW DETECTION FROM VERY HIGH RESOLUTON SATELLITE IMAGE USING GRABCUT SEGMENTATION AND RATIO-BAND ALGORITHMS

    Directory of Open Access Journals (Sweden)

    N. M. S. M. Kadhim

    2015-03-01

    Full Text Available Very-High-Resolution (VHR satellite imagery is a powerful source of data for detecting and extracting information about urban constructions. Shadow in the VHR satellite imageries provides vital information on urban construction forms, illumination direction, and the spatial distribution of the objects that can help to further understanding of the built environment. However, to extract shadows, the automated detection of shadows from images must be accurate. This paper reviews current automatic approaches that have been used for shadow detection from VHR satellite images and comprises two main parts. In the first part, shadow concepts are presented in terms of shadow appearance in the VHR satellite imageries, current shadow detection methods, and the usefulness of shadow detection in urban environments. In the second part, we adopted two approaches which are considered current state-of-the-art shadow detection, and segmentation algorithms using WorldView-3 and Quickbird images. In the first approach, the ratios between the NIR and visible bands were computed on a pixel-by-pixel basis, which allows for disambiguation between shadows and dark objects. To obtain an accurate shadow candidate map, we further refine the shadow map after applying the ratio algorithm on the Quickbird image. The second selected approach is the GrabCut segmentation approach for examining its performance in detecting the shadow regions of urban objects using the true colour image from WorldView-3. Further refinement was applied to attain a segmented shadow map. Although the detection of shadow regions is a very difficult task when they are derived from a VHR satellite image that comprises a visible spectrum range (RGB true colour, the results demonstrate that the detection of shadow regions in the WorldView-3 image is a reasonable separation from other objects by applying the GrabCut algorithm. In addition, the derived shadow map from the Quickbird image indicates

  10. Preparing students for clerkship: a resident shadowing program.

    Science.gov (United States)

    Turner, Simon R; White, Jonathan; Poth, Cheryl; Rogers, W Todd

    2012-09-01

    The preparation of medical students for clerkship has been criticized, in terms of both students understanding of their new role as clinical trainees and their ability to carry out that role. To begin to address this gap, the authors report the development, implementation, and assessment of a novel program in which first-year medical students shadow first-year residents during their clinical duties. The program matches each student to a single resident, whom they shadow for several hours, once per month, for eight months. In the programs inaugural year (2009-10), 83 student-resident pairs participated; over 70% responded to pre- and post-intervention questionnaires, which included an 18-item preparedness scale. The authors used those responses to evaluate the program. Compared to students in a control group, the students in the program assessed themselves as better prepared to learn in a clinical setting. The low-cost student-resident shadowing program described in this article provided an early and structured introduction to the clinical environment, which may help prepare students for the transition into clerkship.

  11. COMPUTER-AIDED DETECTION OF ACINAR SHADOWS IN CHEST RADIOGRAPHS

    Directory of Open Access Journals (Sweden)

    Tao Xu

    2013-05-01

    Full Text Available Despite the technological advances in medical diagnosis, accurate detection of infectious tuberculosis (TB still poses challenges due to complex image features and thus infectious TB continues to be a public health problem of global proportions. Currently, the detection of TB is mainly conducted visually by radiologists examining chest radiographs (CXRs. To reduce the backlog of CXR examination and provide more precise quantitative assessment, computer-aided detection (CAD systems for potential lung lesions have been increasingly adopted and commercialized for clinical practice. CADs work as supporting tools to alert radiologists on suspected features that could have easily been neglected. In this paper, an effective CAD system aimed for acinar shadow regions detection in CXRs is proposed. This system exploits textural and photometric features analysis techniques which include local binary pattern (LBP, grey level co-occurrence matrix (GLCM and histogram of oriented gradients (HOG to analyze target regions in CXRs. Classification of acinar shadows using Adaboost is then deployed to verify the performance of a combination of these techniques. Comparative study in different image databases shows that the proposed CAD system delivers consistent high accuracy in detecting acinar shadows.

  12. A Compact Ring Design with Tunable Momentum Compaction

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Y.; /SLAC

    2012-05-17

    A storage ring with tunable momentum compaction has the advantage in achieving different RMS bunch length with similar RF capacity, which is potentially useful for many applications, such as linear collider damping ring and predamping ring where injected beam has a large energy spread and a large transverse emittance. A tunable bunch length also makes the commissioning and fine tuning easier in manipulating the single bunch instabilities. In this paper, a compact ring design based on a supercell is presented, which achieves a tunable momentum compaction while maintaining a large dynamic aperture.

  13. A study on the shielding element using Monte Carlo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki Jeong [Dept. of Radiology, Konkuk University Medical Center, Seoul (Korea, Republic of); Shim, Jae Goo [Dept. of Radiologic Technology, Daegu Health College, Daegu (Korea, Republic of)

    2017-06-15

    In this research, we simulated the elementary star shielding ability using Monte Carlo simulation to apply medical radiation shielding sheet which can replace existing lead. In the selection of elements, mainly elements and metal elements having a large atomic number, which are known to have high shielding performance, recently, various composite materials have improved shielding performance, so that weight reduction, processability, In consideration of activity etc., 21 elements were selected. The simulation tools were utilized Monte Carlo method. As a result of simulating the shielding performance by each element, it was estimated that the shielding ratio is the highest at 98.82% and 98.44% for tungsten and gold.

  14. WASTE HANDLING BUILDING SHIELD WALL ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    D. Padula

    2000-01-13

    The scope of this analysis is to estimate the shielding wall, ceiling or equivalent door thicknesses that will be required in the Waste Handling Building to maintain the radiation doses to personnel within acceptable limits. The shielding thickness calculated is the minimum required to meet administrative limits, and not necessarily what will be recommended for the final design. The preliminary evaluations will identify the areas which have the greatest impact on mechanical and facility design concepts. The objective is to provide the design teams with the necessary information to assure an efficient and effective design.

  15. Experimental realization of open magnetic shielding

    Science.gov (United States)

    Gu, C.; Chen, S.; Pang, T.; Qu, T.-M.

    2017-05-01

    The detection of extremely low magnetic fields has various applications in the area of fundamental research, medical diagnosis, and industry. Extracting the valuable signals from noises often requires magnetic shielding facilities. We demonstrated directly from Maxwell's equations that specifically designed superconductor coils can exactly shield the magnetic field to an extremely low value. We experimentally confirmed this effect in the frequency spectrum of 0.01-10 000 Hz and improved the electromagnetic environment in a hospital, a leading hospital in magnetocardiograph study in China.

  16. Novel Concepts for Radiation Shielding Materials

    Science.gov (United States)

    Oliva-Buisson, Yvette J.

    2014-01-01

    It is critical that safety factors be maximized with respect to long duration, extraterrestrial space flight. Any significant improvement in radiation protection will be critical in ensuring the safety of crew and hardware on such missions. The project goal is to study novel concepts for radiation shielding materials that can be used for long-duration space missions. As part of this project we will investigate the use of thin films for the evaluation of a containment system that can retain liquid hydrogen and provide the necessary hydrogen density for effective shielding.

  17. AN ASSESSMENT OF SHADOW ENHANCED URBAN REMOTE SENSING IMAGERY OF A COMPLEX CITY – HONG KONG

    Directory of Open Access Journals (Sweden)

    C.-Y. Wan

    2012-07-01

    Full Text Available Large portions of shadowed areas in satellite images of urban areas can affect the accuracy of classification and thus reduce an image's effectiveness in urban remote sensing applications. This is particularly acute in cities such as Hong Kong where dense high-rise buildings cast many long shadows across a variety of different surface types. One solution to this problem is to enhance shadowed areas so their spectral range becomes closer to their corresponding non-shadowed areas. Shadowed areas were automatically selected and two techniques, Gamma correction and Linear Correlation Correction, were applied to three study sites of a 2.4 m Quickbird image. The selected study sites represent typical urban types of Hong Kong, ranging from high-rise commercial to low-rise residential areas. The shadow detection algorithm is based on the spectral shape index and its limitation is discussed. The histograms of the corresponding non-shadowed areas, the original and the enhanced shadow areas are used to compare the spectral range. The results show that the enhanced areas, in band ratios such as NDVI, show greater similarity after enhancement, but they also look darker than the non-shadowed areas. Where continuous shadowed areas such as in commercial areas, the spectral range cannot be restored.

  18. The Influence of Cast Shadows on the Detection of Three-Dimensional Curved Contour Structure.

    Science.gov (United States)

    Khuu, Sieu K; Honson, Vanessa J; Challinor, Kirsten L

    2016-04-01

    Cast shadows have been shown to provide an effective ordinal cue to the depth position of objects. In the present study, two experiments investigated the effectiveness of cast shadows in facilitating the detection of spatial contours embedded in a field of randomly placed elements. In Experiment 1, the separation between the cast shadow and the contour was systematically increased to effectively signal different contour depth positions (relative to background elements), and this was repeated for patterns in which the lighting direction was above and from below. Increasing the shadow separation improved contour detection performance, but the degree to which sensitivity changed was dependent on the lighting direction. Patterns in which the light was from above were better detected than patterns in which the lighting direction was from below. This finding is consistent with the visual system assuming a "light-from-above rule" when processing cast shadows. In Experiment 2, we examined the degree to which changing the shape of the cast shadow (by randomly jittering the position of local cast shadow elements) affected the ability of the visual system to rely on the cast shadow to cue the depth position of the contour. Consistent with a coarse scale analysis, we find that cast shadows remained an effective depth cue even at large degrees of element jitter. Our findings demonstrate that cast shadows provide an effective means of signaling depth, which aids the process of contour integration, and this process is largely tolerant of local variations in lighting direction. © The Author(s) 2016.

  19. Evaluating the Effects of Shadow Detection on QuickBird Image Classification and Spectroradiometric Restoration

    Directory of Open Access Journals (Sweden)

    Marvin E. Bauer

    2013-09-01

    Full Text Available Shadows in high resolution imagery create significant problems for urban land cover classification and environmental application. We first investigated whether shadows were intrinsically different and hypothetically possible to separate from each other with ground spectral measurements. Both pixel-based and object-oriented methods were used to evaluate the effects of shadow detection on QuickBird image classification and spectroradiometric restoration. In each method, shadows were detected and separated either with or without histogram thresholding, and subsequently corrected with a k-nearest neighbor algorithm and a linear correlation correction. The results showed that shadows had distinct spectroradiometric characteristics, thus, could be detected with an optimal brightness threshold and further differentiated with a scene-based near infrared ratio. The pixel-based methods generally recognized more shadow areas and with statistically higher accuracy than the object-oriented methods. The effects of the prior shadow thresholding were not statistically significant. The accuracy of the final land cover classification, after accounting for the shadow detection and separation, was significantly higher for the pixel-based methods than for the object-oriented methods, although both achieved similar accuracy for the non-shadow classes. Both radiometric restoration algorithms significantly reduced shadow areas in the original satellite images.

  20. SOCIO-ECONOMIC NATURE OF SHADOW ECONOMY AND CAUSES OF ITS DEVELOPMENT IN ENTREPRENEURSHIP

    Directory of Open Access Journals (Sweden)

    I. Mazur

    2017-01-01

    Full Text Available The socio-economic nature of the shadow economy is revealed. The shadow economy has both positive and negative signs for the society; the possibility for the population to survive in conditions of economic crisis, reducing transaction costs authors refer to positive signs, and the destructive economic development to negative. The common (prohibitions and restrictions and partial (high tax burden and inefficient system of its administration; numerous bureaucratic procedures; mistrust to the government institutions and the judiciary; corruption in all levels of the governance, etc. causes of the shadow economy in entrepreneurship are disclosed. It is argued that the shadow economy is neither a sector nor a certain part of the legal economy, it can be in any sector of the legal economy closely interlaced with it, and therefore its limits cannot be clearly identified (determine in the formal economy. The shadow economy is not possible to determine especially in the information society. The categories of the shadow economy and its structuring are suggested. It has been researched the historical roots of the shadow economy spread in entrepreneurship, and lie in the shadow of public-private partnership which carries interests of "civil servant-entrepreneurs" and allows to manage state resources and control market. Therefore, the shadow policy creates favorable conditions for the entrepreneurs to work in the shadow. At the same time, access to the shadow entails stricter regulation by the state. It is proved that corruption is a part of the shadow economy, not an independent phenomenon, so they should be research comprehensively and systematically. Instead of overcoming the shadow economy and its component - corruption has been suggested to establish favorable business environment for their unfavorable existence, that is to carry out deshadowing of the economy.

  1. Compact Dexterous Robotic Hand

    Science.gov (United States)

    Lovchik, Christopher Scott (Inventor); Diftler, Myron A. (Inventor)

    2001-01-01

    A compact robotic hand includes a palm housing, a wrist section, and a forearm section. The palm housing supports a plurality of fingers and one or more movable palm members that cooperate with the fingers to grasp and/or release an object. Each flexible finger comprises a plurality of hingedly connected segments, including a proximal segment pivotally connected to the palm housing. The proximal finger segment includes at least one groove defining first and second cam surfaces for engagement with a cable. A plurality of lead screw assemblies each carried by the palm housing are supplied with power from a flexible shaft rotated by an actuator and output linear motion to a cable move a finger. The cable is secured within a respective groove and enables each finger to move between an opened and closed position. A decoupling assembly pivotally connected to a proximal finger segment enables a cable connected thereto to control movement of an intermediate and distal finger segment independent of movement of the proximal finger segment. The dexterous robotic hand closely resembles the function of a human hand yet is light weight and capable of grasping both heavy and light objects with a high degree of precision.

  2. Compact photoacoustic tomography system

    Science.gov (United States)

    Kalva, Sandeep Kumar; Pramanik, Manojit

    2017-03-01

    Photoacoustic tomography (PAT) is a non-ionizing biomedical imaging modality which finds applications in brain imaging, tumor angiogenesis, monitoring of vascularization, breast cancer imaging, monitoring of oxygen saturation levels etc. Typical PAT systems uses Q-switched Nd:YAG laser light illumination, single element large ultrasound transducer (UST) as detector. By holding the UST in horizontal plane and moving it in a circular motion around the sample in full 2π radians photoacoustic data is collected and images are reconstructed. The horizontal positioning of the UST make the scanning radius large, leading to larger water tank and also increases the load on the motor that rotates the UST. To overcome this limitation, we present a compact photoacoustic tomographic (ComPAT) system. In this ComPAT system, instead of holding the UST in horizontal plane, it is held in vertical plane and the photoacoustic waves generated at the sample are detected by the UST after it is reflected at 45° by an acoustic reflector attached to the transducer body. With this we can reduce the water tank size and load on the motor, thus overall PAT system size can be reduced. Here we show that with the ComPAT system nearly similar PA images (phantom and in vivo data) can be obtained as that of the existing PAT systems using both flat and cylindrically focused transducers.

  3. RadShield: semiautomated shielding design using a floor plan driven graphical user interface.

    Science.gov (United States)

    DeLorenzo, Matthew C; Wu, Dee H; Yang, Kai; Rutel, Isaac B

    2016-09-08

    The purpose of this study was to introduce and describe the development of RadShield, a Java-based graphical user interface (GUI), which provides a base design that uniquely performs thorough, spatially distributed calculations at many points and reports the maximum air-kerma rate and barrier thickness for each barrier pursuant to NCRP Report 147 methodology. Semiautomated shielding design calculations are validated by two approaches: a geometry-based approach and a manual approach. A series of geometry-based equations were derived giv-ing the maximum air-kerma rate magnitude and location through a first derivative root finding approach. The second approach consisted of comparing RadShield results with those found by manual shielding design by an American Board of Radiology (ABR)-certified medical physicist for two clinical room situations: two adjacent catheterization labs, and a radiographic and fluoroscopic (R&F) exam room. RadShield's efficacy in finding the maximum air-kerma rate was compared against the geometry-based approach and the overall shielding recommendations by RadShield were compared against the medical physicist's shielding results. Percentage errors between the geometry-based approach and RadShield's approach in finding the magnitude and location of the maximum air-kerma rate was within 0.00124% and 14 mm. RadShield's barrier thickness calculations were found to be within 0.156 mm lead (Pb) and 0.150 mm lead (Pb) for the adjacent catheteriza-tion labs and R&F room examples, respectively. However, within the R&F room example, differences in locating the most sensitive calculation point on the floor plan for one of the barriers was not considered in the medical physicist's calculation and was revealed by the RadShield calculations. RadShield is shown to accurately find the maximum values of air-kerma rate and barrier thickness using NCRP Report 147 methodology. Visual inspection alone of the 2D X-ray exam distribution by a medical physicist may not

  4. A Semi-Empirical Model for Tilted-Gun Planar Magnetron Sputtering Accounting for Chimney Shadowing

    Science.gov (United States)

    Bunn, J. K.; Metting, C. J.; Hattrick-Simpers, J.

    2015-01-01

    Integrated computational materials engineering (ICME) approaches to composition and thickness profiles of sputtered thin-film samples are the key to expediting materials exploration for these materials. Here, an ICME-based semi-empirical approach to modeling the thickness of thin-film samples deposited via magnetron sputtering is developed. Using Yamamura's dimensionless differential angular sputtering yield and a measured deposition rate at a point in space for a single experimental condition, the model predicts the deposition profile from planar DC sputtering sources. The model includes corrections for off-center, tilted gun geometries as well as shadowing effects from gun chimneys used in most state-of-the-art sputtering systems. The modeling algorithm was validated by comparing its results with experimental deposition rates obtained from a sputtering system utilizing sources with a multi-piece chimney assembly that consists of a lower ground shield and a removable gas chimney. Simulations were performed for gun-tilts ranging from 0° to 31.3° from the vertical with and without the gas chimney installed. The results for the predicted and experimental angular dependence of the sputtering deposition rate were found to have an average magnitude of relative error of for a 0°-31.3° gun-tilt range without the gas chimney, and for a 17.7°-31.3° gun-tilt range with the gas chimney. The continuum nature of the model renders this approach reverse-optimizable, providing a rapid tool for assisting in the understanding of the synthesis-composition-property space of novel materials.

  5. The shadow of a doubt ? Evidence for perceptuo-motor linkage during auditory and audiovisual close shadowing

    Directory of Open Access Journals (Sweden)

    Lucie eScarbel

    2014-06-01

    Full Text Available One classical argument in favor of a functional role of the motor system in speech perception comes from the close shadowing task in which a subject has to identify and to repeat as quickly as possible an auditory speech stimulus. The fact that close shadowing can occur very rapidly and much faster than manual identification of the speech target is taken to suggest that perceptually-induced speech representations are already shaped in a motor-compatible format. Another argument is provided by audiovisual interactions often interpreted as referring to a multisensory-motor framework. In this study, we attempted to combine these two paradigms by testing whether the visual modality could speed motor response in a close-shadowing task. To this aim, both oral and manual responses were evaluated during the perception of auditory and audio-visual speech stimuli, clear or embedded in white noise. Overall, oral responses were faster than manual ones, but it also appeared that they were less accurate in noise, which suggests that motor representations evoked by the speech input could be rough at a first processing stage. In the presence of acoustic noise, the audiovisual modality led to both faster and more accurate responses than the auditory modality. No interaction was however observed between modality and response. Altogether, these results are interpreted within a two-stage sensory-motor framework, in which the auditory and visual streams are integrated together and with internally generated motor representations before a final decision may be available.

  6. Shielding Effectiveness Measurements using a Reverberation Chamber

    NARCIS (Netherlands)

    Leferink, Frank Bernardus Johannes; Bergsma, J.G.; Bergsma, Hans; van Etten, Wim

    2006-01-01

    Shielding effectiveness measurements have been performed using a reverberation chamber. The reverberation chamber methodology as we1l as the measurement setup is described and some results are given. Samples include glass reinforced plastic panels, aluminum panels with many holes, wire mesh, among

  7. SHIELD: Observations of Three Candidate Interacting Systems

    NARCIS (Netherlands)

    Ruvolo, Elizabeth; Miazzo, Masao; Cannon, John M.; McNichols, Andrew; Teich, Yaron; Adams, Elizabeth A.; Giovanelli, Riccardo; Haynes, Martha P.; McQuinn, Kristen B.; Salzer, John Joseph; Skillman, Evan D.; Dolphin, Andrew E.; Elson, Edward C.; Haurberg, Nathalie C.; Huang, Shan; Janowiecki, Steven; Jozsa, Gyula; Leisman, Luke; Ott, Juergen; Papastergis, Emmanouil; Rhode, Katherine L.; Saintonge, Amelie; Van Sistine, Angela; Warren, Steven R.

    Abstract:The “Survey of HI in Extremely Low-mass Dwarfs” (SHIELD) is a multiwavelength study of local volume low-mass galaxies. Using the now-complete Arecibo Legacy Fast ALFA (ALFALFA) source catalog, 82 systems are identified that meet distance, line width, and HI flux criteria for being gas-rich,

  8. The Tower Shielding Facility: Its glorious past

    Energy Technology Data Exchange (ETDEWEB)

    Muckenthaler, F.J.

    1997-05-07

    The Tower Shielding Facility (TSF) is the only reactor facility in the US that was designed and built for radiation-shielding studies in which both the reactor source and shield samples could be raised into the air to allow measurements to be made without interference from ground scattering or other spurious effects. The TSF proved its usefulness as many different programs were successfully completed. It became active in work for the Defense Atomic Support Agency (DASA) Space Nuclear Auxiliary Power, Defense Nuclear Agency, Liquid Metal Fast Breeder Reactor Program, the Gas-Cooled and High-Temperature Gas-Cooled Reactor programs, and the Japanese-American Shielding Program of Experimental Research, just to mention a few of the more extensive ones. The history of the TSF as presented in this report describes the various experiments that were performed using the different reactors. The experiments are categorized as to the programs which they supported and placed in corresponding chapters. The experiments are described in modest detail, along with their purpose when appropriate. Discussion of the results is minimal, but references are given to more extensive topical reports.

  9. Design and analysis of ITER shield blanket

    Energy Technology Data Exchange (ETDEWEB)

    Ohmori, Junji; Hatano, Toshihisa; Ezato, Kouichiro [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment] [and others

    1998-12-01

    This report includes electromagnetic analyses for ITER shielding blanket modules, fabrication methods for the blanket modules and the back plate, the design and the fabrication methods for port limiter have been investigated. Studies on the runaway electron impact for Be armor have been also performed. (J.P.N.)

  10. MPACT Subgroup Self-Shielding Efficiency Improvements

    Energy Technology Data Exchange (ETDEWEB)

    Stimpson, Shane [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Liu, Yuxuan [Univ. of Michigan, Ann Arbor, MI (United States); Collins, Benjamin S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Clarno, Kevin T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-08-31

    Recent developments to improve the efficiency of the MOC solvers in MPACT have yielded effective kernels that loop over several energy groups at once, rather that looping over one group at a time. These kernels have produced roughly a 2x speedup on the MOC sweeping time during eigenvalue calculation. However, the self-shielding subgroup calculation had not been reevaluated to take advantage of these new kernels, which typically requires substantial solve time. The improvements covered in this report start by integrating the multigroup kernel concepts into the subgroup calculation, which are then used as the basis for further extensions. The next improvement that is covered is what is currently being termed as “Lumped Parameter MOC”. Because the subgroup calculation is a purely fixed source problem and multiple sweeps are performed only to update the boundary angular fluxes, the sweep procedure can be condensed to allow for the instantaneous propagation of the flux across a spatial domain, without the need to sweep along all segments in a ray. Once the boundary angular fluxes are considered to be converged, an additional sweep that will tally the scalar flux is completed. The last improvement that is investigated is the possible reduction of the number of azimuthal angles per octant in the shielding sweep. Typically 16 azimuthal angles per octant are used for self-shielding and eigenvalue calculations, but it is possible that the self-shielding sweeps are less sensitive to the number of angles than the full eigenvalue calculation.

  11. AB INITIO STUDY, INVESTIGATION OF NMR SHIELDING ...

    African Journals Online (AJOL)

    Preferred Customer

    Ab initio study, investigation of NMR shielding tensors, NBO and vibrational frequency. Bull. Chem. Soc. Ethiop. 2010, 24(2). 231. Gas phase results. In order to study mechanism of the reactions, structure corresponding to reactants, transition states and products were optimized in level of theory. Figure 1 shows the ...

  12. Remote demolition of the thermal insulation and preparative actions for the demounting of the primary shielding; Fernhantierte Demontage der Waermeisolierung und Vorbereitungen zum Ausbau der Primaerabschirmung

    Energy Technology Data Exchange (ETDEWEB)

    Graf, A.; Fleisch, J.; Neff, S. [WAK GmbH, Eggenstein-Leopoldshafen (Germany); Klute, S.; Koselowski, E. [Siempelkamp Nukleartechnik, Heidelberg (Germany)

    2011-07-01

    The compact sodium cooled reactor (KNK) was the prototype of a fast breeder reactor. The reactor was shut down in 1991, the deconstruction was planned and started. The deconstruction and renaturization is performed according to11 separate decommissioning licenses. The first 8 Licenses are completely fulfilled. The authors describe the work to be performed within the 9th license: after the demounting and cutting of the reactor tank the thermal insulation, the primary shielding and the activated part of the biological shield have to be demounted. Appropriate remote handled demounting tools had to be developed, constructed and tested. The first experiences with the tools show that only few optimizations are required.

  13. Software Tools for Measuring and Calculating Electromagnetic Shielding Effectiveness

    National Research Council Canada - National Science Library

    Tesny, Neal

    2005-01-01

    The evaluation and the analysis of high-altitude electromagnetic pulse response of shielded enclosures require the availability of software tools able to acquire data and calculate shielding effectiveness...

  14. Summary of Prometheus Radiation Shielding Nuclear Design Analysis

    Energy Technology Data Exchange (ETDEWEB)

    J. Stephens

    2006-01-13

    This report transmits a summary of radiation shielding nuclear design studies performed to support the Prometheus project. Together, the enclosures and references associated with this document describe NRPCT (KAPL & Bettis) shielding nuclear design analyses done for the project.

  15. Early test facilities and analytic methods for radiation shielding: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Ingersoll, D T [comp.; Oak Ridge National Lab., TN (United States); Ingersoll, J K [comp.; Tec-Com, Knoxville, TN (United States)

    1992-11-01

    This report represents a compilation of eight papers presented at the 1992 American Nuclear Society/European Nuclear Society International Meeting. The meeting is of special significance since it commemorates the fiftieth anniversary of the first controlled nuclear chain reaction. The papers contained in this report were presented in a special session organized by the Radiation Protection and Shielding Division in keeping with the historical theme of the meeting. The paper titles are good indicators of their content and are: (1) The origin of radiation shielding research: The Oak Ridge experience, (2) Shielding research at the hanford site, (3) Aircraft shielding experiments at General Dynamics Fort Worth, 1950-1962, (4) Where have the neutrons gone , a history of the tower shielding facility, (5) History and evolution of buildup factors, (6) Early shielding research at Bettis atomic power laboratory, (7) UK reactor shielding: then and now, (8) A very personal view of the development of radiation shielding theory.

  16. Compact instantaneous water heater

    Energy Technology Data Exchange (ETDEWEB)

    Azevedo, Jorge G.W.; Machado, Antonio R.; Ferraz, Andre D.; Rocha, Ivan C.C. da; Konishi, Ricardo [Companhia de Gas de Santa Catarina (SCGAS), Florianopolis, SC (Brazil); Lehmkuhl, Willian A.; Francisco Jr, Roberto W.; Hatanaka, Ricardo L.; Pereira, Fernando M.; Oliveira, Amir A.M. [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil)

    2012-07-01

    This paper presents an experimental study of combustion in an inert porous medium in a liquid heating device application. This project aims to increase efficiency in the application of natural gas in residential and commercial sectors with the use of advanced combustion and heat transfer. The goal is to facilitate the development of a high performance compact water heater allowing hot water supply for up to two simultaneous showers. The experiment consists in a cylindrical porous burner with an integrated annular water heat exchanger. The reactants were injected radially into the burner and the flame stabilizes within the porous matrix. The water circulates in a coiled pipe positioned at the center of the burner. This configuration allows for heat transfer by conduction and radiation from the solid matrix to the heat exchanger. This article presented preliminary experimental results of a new water heater based on an annular porous burner. The range of equivalence ratios tested varied from 0.65 to 0.8. The power range was varied from 3 to 5 kW. Increasing the equivalence ratio or decreasing the total power input of the burner resulted in increased thermal efficiencies of the water heater. Thermal efficiencies varying from 60 to 92% were obtained. The condition for the goal of a comfortable bath was 20 deg C for 8-12 L/min. This preliminary prototype has achieved water temperature of 11deg C for 5 L/min. Further optimizations will be necessary in order to achieve intense heating with high thermal efficiency. (author)

  17. Partial shadowing detection based on equivalent thermal voltage monitoring for PV module diagnostics

    DEFF Research Database (Denmark)

    Sera, Dezso; Teodorescu, Remus; Rodriguez, Pedro

    2009-01-01

    Partial shadowing of photovoltaic systems can overproportionally reduce the energy yield and lead to early ageing and failure of the shadowed cells. Large area shadows are relatively easy to detect due to the eminent power reduction and decrease of fill factor. However, small area partial shadows...... in a larger system do not have a very obvious effect on the output power or fill factor of the PV array and can remain undetected, leading to failure. In this paper a method for detecting small area partial shadows, based on equivalent thermal voltage, is presented. A simplified expression of the equivalent...... thermal voltage is proposed, which increases the robustness against measurement errors and model limitations at low irradiation conditions. Experimental results confirm the high sensitivity of the method even to a relatively small area shadow, while showing very good robustness against increase in series...

  18. Multihelix rotating shield brachytherapy for cervical cancer

    Energy Technology Data Exchange (ETDEWEB)

    Dadkhah, Hossein [Department of Biomedical Engineering, University of Iowa, 1402 Seamans Center for the Engineering Arts and Sciences, Iowa City, Iowa 52242 (United States); Kim, Yusung; Flynn, Ryan T., E-mail: ryan-flynn@uiowa.edu [Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242 (United States); Wu, Xiaodong [Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242 and Department of Electrical and Computer Engineering, University of Iowa, 4016 Seamans Center for the Engineering Arts and Sciences, Iowa City, Iowa 52242 (United States)

    2015-11-15

    Purpose: To present a novel brachytherapy technique, called multihelix rotating shield brachytherapy (H-RSBT), for the precise angular and linear positioning of a partial shield in a curved applicator. H-RSBT mechanically enables the dose delivery using only linear translational motion of the radiation source/shield combination. The previously proposed approach of serial rotating shield brachytherapy (S-RSBT), in which the partial shield is rotated to several angular positions at each source dwell position [W. Yang et al., “Rotating-shield brachytherapy for cervical cancer,” Phys. Med. Biol. 58, 3931–3941 (2013)], is mechanically challenging to implement in a curved applicator, and H-RSBT is proposed as a feasible solution. Methods: A Henschke-type applicator, designed for an electronic brachytherapy source (Xoft Axxent™) and a 0.5 mm thick tungsten partial shield with 180° or 45° azimuthal emission angles and 116° asymmetric zenith angle, is proposed. The interior wall of the applicator contains six evenly spaced helical keyways that rigidly define the emission direction of the partial radiation shield as a function of depth in the applicator. The shield contains three uniformly distributed protruding keys on its exterior wall and is attached to the source such that it rotates freely, thus longitudinal translational motion of the source is transferred to rotational motion of the shield. S-RSBT and H-RSBT treatment plans with 180° and 45° azimuthal emission angles were generated for five cervical cancer patients with a diverse range of high-risk target volume (HR-CTV) shapes and applicator positions. For each patient, the total number of emission angles was held nearly constant for S-RSBT and H-RSBT by using dwell positions separated by 5 and 1.7 mm, respectively, and emission directions separated by 22.5° and 60°, respectively. Treatment delivery time and tumor coverage (D{sub 90} of HR-CTV) were the two metrics used as the basis for evaluation and

  19. A novel preparation of silver-plated polyacrylonitrile fibers functionalized with antibacterial and electromagnetic shielding properties

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wei; Li, Weiya; Gao, Cuicui; Tian, Weicheng [College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620 (China); Sun, Bin [College of Material Science and Engineering, Donghua University, Shanghai 201620 (China); Yu, Dan, E-mail: yudan@dhu.edu.cn [College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620 (China)

    2015-07-01

    Highlights: • We propose a novel modification method to initiate silver electroless plating on PAN fiber without noble metal catalyst. • The silver-plated fiber we fabricated has good electromagnetic shielding effectiveness and antibacterial properties. • The metal layer has good adhesion strength and the properties of the silver-plated fiber can stand 30 cycles of standard washing. - Abstract: Polyacrylonitrile (PAN) fibers with antibacterial, electromagnetic shielding and antistatic functionalities were fabricated in this paper through modifying PAN fibers with (3-aminopropyl)triethoxysilane (APTES) and 3-mercaptopropyltriethoxysilane (MPTES) sequentially and followed with silver electroless plating. The silver layer on PAN fiber surface was characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD). The results show that the silver layer was plated uniformly and compactly. The surface resistance of plated fabric was about 40 mΩ/sq on average. The antibacterial tests demonstrate that silver-plated PAN fiber exhibits excellent antibacterial property against S. aureus and E. coli with a non-leaching characteristic. The antibacterial property remains good after 30 cycles of standard washing, which is a strong proof of a durable adhesion between metal layer and fiber. The shielding effectiveness (SE) of silver-plated PAN fabric before and after 30 cycles of standard washing was about 40–80 dB and 35–50 dB, respectively. This resultant fiber can be used in many occasions for reducing or preventing electromagnetic interference (EMI) and electromagnetic hazards.

  20. Compact, Airborne Multispecies Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Small Business Innovative Research Phase I proposal seeks to develop a compact mid-infrared laser spectrometer to benefit Earth science research activities. To...

  1. Compact energy conversion module Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This STTR project delivers a compact vibration-based Energy Conversion Module (ECM) that powers sensors for purposes like structural health monitoring (SHM). NASA...

  2. Compact, Ultrasensitive Formaldehyde Monitor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Small Business Innovative Research Phase II proposal seeks to develop a compact UV laser ?based sensor for Earth science and planetary atmosphere exploration....

  3. What Is Business's Social Compact?

    Science.gov (United States)

    Avishai, Bernard

    1994-01-01

    Under the "new" social compact, businesses must focus on continuous learning and thus have both an obligation to support teaching and an opportunity to profit from it. Learning organizations must also be teaching organizations. (SK)

  4. A Parallel Compact Hash Table

    NARCIS (Netherlands)

    van der Vegt, Steven; Laarman, Alfons; Vojnar, Tomas

    2011-01-01

    We present the first parallel compact hash table algorithm. It delivers high performance and scalability due to its dynamic region-based locking scheme with only a fraction of the memory requirements of a regular hash table.

  5. Collapse settlement in compacted soils

    CSIR Research Space (South Africa)

    Booth, AR

    1977-01-01

    Full Text Available Research into collapse settlement in compacted soils is described, with special reference to recent cases in Southern Africa where collapse settlement occurred in road embankments following wetting of the soil. The laboratory work described...

  6. Updating the theoretical analysis of the weak gravitational shielding experiment

    CERN Document Server

    Modanese, G

    1996-01-01

    The most recent data about the weak gravitational shielding produced recently through a levitating and rotating HTC superconducting disk show a very weak dependence of the shielding value ($\\sim 1 \\%$) on the height above the disk. We show that whilst this behaviour is incompatible with an intuitive vectorial picture of the shielding, it is consistently explained by our theoretical model. The expulsive force observed at the border of the shielded zone is due to energy conservation.

  7. Fast Shadow Detection from a Single Image Using a Patched Convolutional Neural Network

    OpenAIRE

    Hosseinzadeh, Sepideh; Shakeri, Moein; Zhang, Hong

    2017-01-01

    In recent years, various shadow detection methods from a single image have been proposed and used in vision systems; however, most of them are not appropriate for the robotic applications due to the expensive time complexity. This paper introduces a fast shadow detection method using a deep learning framework, with a time cost that is appropriate for robotic applications. In our solution, we first obtain a shadow prior map with the help of multi-class support vector machine using statistical ...

  8. ANALYZING SPECTRAL CHARACTERISTICS OF SHADOW AREA FROM ADS-40 HIGH RADIOMETRIC RESOLUTION AERIAL IMAGES

    Directory of Open Access Journals (Sweden)

    Y.-T. Hsieh

    2016-06-01

    Full Text Available The shadows in optical remote sensing images are regarded as image nuisances in numerous applications. The classification and interpretation of shadow area in a remote sensing image are a challenge, because of the reduction or total loss of spectral information in those areas. In recent years, airborne multispectral aerial image devices have been developed 12-bit or higher radiometric resolution data, including Leica ADS-40, Intergraph DMC. The increased radiometric resolution of digital imagery provides more radiometric details of potential use in classification or interpretation of land cover of shadow areas. Therefore, the objectives of this study are to analyze the spectral properties of the land cover in the shadow areas by ADS-40 high radiometric resolution aerial images, and to investigate the spectral and vegetation index differences between the various shadow and non-shadow land covers. According to research findings of spectral analysis of ADS-40 image: (i The DN values in shadow area are much lower than in nonshadow area; (ii DN values received from shadowed areas that will also be affected by different land cover, and it shows the possibility of land cover property retrieval as in nonshadow area; (iii The DN values received from shadowed regions decrease in the visible band from short to long wavelengths due to scattering; (iv The shadow area NIR of vegetation category also shows a strong reflection; (v Generally, vegetation indexes (NDVI still have utility to classify the vegetation and non-vegetation in shadow area. The spectral data of high radiometric resolution images (ADS-40 is potential for the extract land cover information of shadow areas.

  9. Compaction with Automatic Jog Introduction

    Science.gov (United States)

    1986-11-01

    conserve area. For these reasons, compaction algorithms have gained widespread attention in the VLSI literature S ,[4, 5, 9, 111, and have been incorporated...graph is (V,E), then Dijkstra’s algorithm runs in time 6 (IEl - IVI log IV!) using Fibonacci heaps [3]. In contrast, the longest- path algorithm of...however, so that hierarchical compaction can alleviate much of the resource -. 33 pa. .1 N’, problem. It also may be suited to use in channel routing

  10. 30 CFR 56.14213 - Ventilation and shielding for welding.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Ventilation and shielding for welding. 56.14213... Equipment Safety Practices and Operational Procedures § 56.14213 Ventilation and shielding for welding. (a) Welding operations shall be shielded when performed at locations where arc flash could be hazardous to...

  11. Advanced materials and design for electromagnetic interference shielding

    CERN Document Server

    Tong, Xingcun Colin

    2008-01-01

    Exploring the role of EMI shielding in EMC design, this book introduces the design guidelines, materials selection, characterization methodology, manufacturing technology, and future potential of EMI shielding. It covers an array of issues in advanced shielding materials and design solutions, including enclosures and composites.

  12. Spherical warm shield design for infrared imaging systems

    Science.gov (United States)

    Tian, Qijie; Chang, Songtao; He, Fengyun; Li, Zhou; Qiao, Yanfeng

    2017-09-01

    The F-number matching is the primary means to suppress stray radiation for infrared imaging systems. However, it is difficult to achieve exact F-number matching, owing to the restriction from detectors, or multiple F-number design. Hence, an additional shield is required to block the certain thermal radiation. Typical shield is called flat warm shield, which is flat and operates at room temperature. For flat warm shield, it cannot suppress stray radiation while achieving F-number matching. To overcome the restriction, a spherical reflective warm shield is required. First of all, the detailed theory of spherical warm shield design is developed on basis of the principle that stray radiation cannot directly reach the infrared focal plane array. According to the theory developed above, a polished spherical warm shield, whose radius is 18 mm, is designed to match an F/2 infrared detector with an F/4 infrared imaging system. Then, the performance and alignment errors of the designed spherical warm shield are analyzed by simulation. Finally, a contrast experiment between the designed spherical warm shield and two differently processed flat warm shields is performed in a chamber with controllable inside temperatures. The experimental results indicate that the designed spherical warm shield cannot only achieve F-number matching but suppress stray radiation sufficiently. Besides, it is demonstrated that the theory of spherical warm shield design developed in this paper is valid and can be employed by arbitrary infrared imaging systems.

  13. Physical analysis of the shielding capacity for a lightweight apron designed for shielding low intensity scattering X-rays

    National Research Council Canada - National Science Library

    Kim, Seon Chil; Choi, Jeong Ryeol; Jeon, Byeong Kyou

    2016-01-01

    The purpose of this paper is to develop a lightweight apron that will be used for shielding low intensity radiation in medical imaging radiography room and to apply it to a custom-made effective shielding...

  14. A hardware architecture for real-time shadow removal in high-contrast video

    Science.gov (United States)

    Verdugo, Pablo; Pezoa, Jorge E.; Figueroa, Miguel

    2017-09-01

    Broadcasting an outdoor sports event at daytime is a challenging task due to the high contrast that exists between areas in the shadow and light conditions within the same scene. Commercial cameras typically do not handle the high dynamic range of such scenes in a proper manner, resulting in broadcast streams with very little shadow detail. We propose a hardware architecture for real-time shadow removal in high-resolution video, which reduces the shadow effect and simultaneously improves shadow details. The algorithm operates only on the shadow portions of each video frame, thus improving the results and producing more realistic images than algorithms that operate on the entire frame, such as simplified Retinex and histogram shifting. The architecture receives an input in the RGB color space, transforms it into the YIQ space, and uses color information from both spaces to produce a mask of the shadow areas present in the image. The mask is then filtered using a connected components algorithm to eliminate false positives and negatives. The hardware uses pixel information at the edges of the mask to estimate the illumination ratio between light and shadow in the image, which is then used to correct the shadow area. Our prototype implementation simultaneously processes up to 7 video streams of 1920×1080 pixels at 60 frames per second on a Xilinx Kintex-7 XC7K325T FPGA.

  15. Nuclear dependence of structure functions in the shadowing region of deep inelastic scattering

    Energy Technology Data Exchange (ETDEWEB)

    Berger, E.L.; Qiu, Jianwei

    1988-07-27

    A discussion of nuclear shadowing in deep inelastic lepton scattering is presented. We show that the parton recombination model suggests that shadowing should begin to occur at larger values of Bjorken x as A increases. This expectation as well as that of weak dependence on Q/sup 2/, and the trend of the x dependence of the shadowing phenomenon are consistent with recent data. Shadowing at small x is combined with nuclear bound state effects, responsible for nuclear dependence at larger x, to provide description of the A dependence of the structure function for the entire range of x. 21 refs., 5 figs.

  16. How to use 3D shadows for simple microscopy and vibrometry

    Science.gov (United States)

    Parikesit, Gea O. F.; Kusumaningtyas, Indraswari

    2017-07-01

    In 2014, we reported that shadows can be displayed in 3D using a stereoscopic setup. We now report that the 3D shadows can also be used to perform simple measurements, which are suitable for physics education in schools and colleges. Two different types of measurements are demonstrated, i.e. microscopy and vibrometry. Both types of measurements take advantage of the geometrical optics of the 3D shadows, where the 3D position of an object can be estimated using the coordinates of the colored light sources and the coordinates of the colored shadow images. We also include several student activities that can raise the students’ curiosity and capability.

  17. Pacman in the sky with shadows: the effect of cast shadows on the perceptual completion of occluded figures by chimpanzees and humans

    Directory of Open Access Journals (Sweden)

    Imura Tomoko

    2010-07-01

    Full Text Available Abstract Background Humans readily perceive whole shapes as intact when some portions of these shapes are occluded by another object. This type of amodal completion has also been widely reported among nonhuman animals and is related to pictorial depth perception. However, the effect of a cast shadow, a critical pictorial-depth cue for amodal completion has been investigated only rarely from the comparative-cognitive perspective. In the present study, we examined this effect in chimpanzees and humans. Results Chimpanzees were slower in responding to a Pacman target with an occluding square than to the control condition, suggesting that participants perceptually completed the whole circle. When a cast shadow was added to the square, amodal completion occurred in both species. On the other hand, however, critical differences between the species emerged when the cast shadow was added to the Pacman figure, implying that Pacman was in the sky casting a shadow on the square. The cast shadow prevented, to a significant extent, compulsory amodal completion in humans, but had no effect on chimpanzees. Conclusion These results suggest that cast shadows played a critical role in enabling humans to infer the spatial relationship between Pacman and the square. For chimpanzees, however, a cast shadow may be perceived as another "object". A limited role for cast shadows in the perception of pictorial depth has also been reported with respect to human cognitive development. Further studies on nonhuman primates using a comparative-developmental perspective will clarify the evolutionary origin of the role of cast shadows in visual perception.

  18. Robust Lane Sensing and Departure Warning under Shadows and Occlusions

    Directory of Open Access Journals (Sweden)

    Miguel Torres-Torriti

    2013-03-01

    Full Text Available A prerequisite for any system that enhances drivers’ awareness of road conditions and threatening situations is the correct sensing of the road geometry and the vehicle’s relative pose with respect to the lane despite shadows and occlusions. In this paper we propose an approach for lane segmentation and tracking that is robust to varying shadows and occlusions. The approach involves color-based clustering, the use of MSAC for outlier removal and curvature estimation, and also the tracking of lane boundaries. Lane boundaries are modeled as planar curves residing in 3D-space using an inverse perspective mapping, instead of the traditional tracking of lanes in the image space, i.e., the segmented lane boundary points are 3D points in a coordinate frame fixed to the vehicle that have a depth component and belong to a plane tangent to the vehicle’s wheels, rather than 2D points in the image space without depth information. The measurement noise and disturbances due to vehicle vibrations are reduced using an extended Kalman filter that involves a 6-DOF motion model for the vehicle, as well as measurements about the road’s banking and slope angles. Additional contributions of the paper include: (i the comparison of textural features obtained from a bank of Gabor filters and from a GMRF model; and (ii the experimental validation of the quadratic and cubic approximations to the clothoid model for the lane boundaries. The results show that the proposed approach performs better than the traditional gradient-based approach under different levels of difficulty caused by shadows and occlusions.

  19. Robust Lane Sensing and Departure Warning under Shadows and Occlusions

    Science.gov (United States)

    Tapia-Espinoza, Rodolfo; Torres-Torriti, Miguel

    2013-01-01

    A prerequisite for any system that enhances drivers' awareness of road conditions and threatening situations is the correct sensing of the road geometry and the vehicle's relative pose with respect to the lane despite shadows and occlusions. In this paper we propose an approach for lane segmentation and tracking that is robust to varying shadows and occlusions. The approach involves color-based clustering, the use of MSAC for outlier removal and curvature estimation, and also the tracking of lane boundaries. Lane boundaries are modeled as planar curves residing in 3D-space using an inverse perspective mapping, instead of the traditional tracking of lanes in the image space, i.e., the segmented lane boundary points are 3D points in a coordinate frame fixed to the vehicle that have a depth component and belong to a plane tangent to the vehicle's wheels, rather than 2D points in the image space without depth information. The measurement noise and disturbances due to vehicle vibrations are reduced using an extended Kalman filter that involves a 6-DOF motion model for the vehicle, as well as measurements about the road's banking and slope angles. Additional contributions of the paper include: (i) the comparison of textural features obtained from a bank of Gabor filters and from a GMRF model; and (ii) the experimental validation of the quadratic and cubic approximations to the clothoid model for the lane boundaries. The results show that the proposed approach performs better than the traditional gradient-based approach under different levels of difficulty caused by shadows and occlusions. PMID:23478598

  20. Between the idea and the reality falls the shadow

    OpenAIRE

    Hogan, Jennifer

    1998-01-01

    non-peer-reviewed The aim of this thesis was to thoroughly immerse myself into the liminal space that lingers between our initial thoughts and realised visions. The shadow, as it were, was the elusive subject I have chased since my childhood. It is an experience, it is the multitude of experiences that make up a lifetime, my driving force. In a literal sense, it is the darkness resulting from placing an agglomeration of matter in the path of light. This is where the idea meets ...

  1. Shadow Affect in Urban Digital (Post Screen) Art

    DEFF Research Database (Denmark)

    Toft, Tanya Søndergaard

    2014-01-01

    The paper considers an affective turn in artistic practices with interactive urban digital screen-based art that evokes a behavioral response in the audience, which I propose as a symptom of the post screen. I propose the affective experience as a mode of exploring presence in the artwork through...... “shadow affect”, as an alternative to experiencing self identification and representation. I argue that a phenomenological understanding is necessary in place of a techno-aesthetic perspective, which would allow for more nuanced understandings of human experience in our digital reality....

  2. How outliers become superstars: what shadow coaches do.

    Science.gov (United States)

    Sullivan, Kevin W

    2012-01-01

    Physicians who score low on patient satisfaction surveys usually don't know what they're doing (or not doing) to cause below-average ratings. Too often, the temporary improvement gained from books and seminars dissipates as providers return to overloaded schedules and variability in patient expectations. Shadow coaching has proved effective for motivated physicians seeking more patient visits, better risk management, and high marks on the payer metrics that will soon affect qualification for Accountable Care, Medical Home, and favorable reimbursement.

  3. Shadow based building extraction from single satellite image

    Science.gov (United States)

    Singh, Gurshamnjot; Jouppi, Mark; Zhang, Zhuoran; Zakhor, Avideh

    2015-03-01

    Automatic building extraction in satellite imagery is an important problem. Existing approaches typically involve stereo processing two or more satellite views of the same region. In this paper, we use shadow analysis coupled with line segment detection and texture segmentation to construct rectangular building approximations from a single satellite image. In addition, we extract building heights to construct a rectilinear height profile for a single region. We characterize the performance of the system in rural and urban regions of Jordan, Philippines, and Australia and demonstrate a detection rate of 76.2 - 86.1% and a false alarm rate of 26.5 - 40.1%.

  4. Asymptotic Ergodic Capacity Analysis of Composite Lognormal Shadowed Channels

    KAUST Repository

    Ansari, Imran Shafique

    2015-05-01

    Capacity analysis of composite lognormal (LN) shadowed links, such as Rician-LN, Gamma-LN, and Weibull-LN, is addressed in this work. More specifically, an exact closed-form expression for the moments of the end-to-end signal-to-noise ratio (SNR) of a single composite link transmission system is presented in terms of well- known elementary functions. Capitalizing on these new moments expressions, we present asymptotically tight lower bounds for the ergodic capacity at high SNR. All the presented results are verified via computer-based Monte-Carlo simulations. © 2015 IEEE.

  5. The classification of 2-compact groups

    DEFF Research Database (Denmark)

    K. S. Andersen, Kasper; Grodal, Jesper

    2009-01-01

    We prove that any connected 2-compact group is classified by its 2-adic root datum, and in particular the exotic 2-compact group DI(4), constructed by Dwyer-Wilkerson, is the only simple 2-compact group not arising as the 2-completion of a compact connected Lie group. Combined with our earlier wo...

  6. Shielding of Electronic Systems against Transient Electromagnetic Interferences

    Directory of Open Access Journals (Sweden)

    H. Herlemann

    2005-01-01

    Full Text Available In order to protect electronic systems against the effects of transient electromagnetic interferences, shields made of electrically conductive material can be used. The subject of this paper is an electrically conductive textile. When applying the shield, a reliable measure is needed in order to determine the effectiveness of the shield to protect against electromagnetic pulses. For this purpose, a time domain measurement technique is presented using double exponential pulses. With these pulses, the susceptibility of an operating electronic device with and without the shield is determined. As a criterion of quality of a shield, the breakdown failure rate found in both cases is compared.

  7. Potential Polymeric Sphere Construction Materials for a Spacecraft Electrostatic Shield

    Science.gov (United States)

    Smith, Joseph G., Jr.; Smith, Trent; Williams, Martha; Youngquist, Robert; Mendell, Wendell

    2006-01-01

    An electrostatic shielding concept for spacecraft radiation protection under NASA s Exploration Systems Research and Technology Program was evaluated for its effectiveness and feasibility. The proposed shield design is reminiscent of a classic quadrupole with positively and negatively charged spheres surrounding the spacecraft. The project addressed materials, shield configuration, power supply, and compared its effectiveness to that of a passive shield. The report herein concerns the identification of commercially available materials that could be used in sphere fabrication. It was found that several materials were needed to potentially construct the spheres for an electrostatic shield operating at 300 MV.

  8. Compact Intracloud Discharges

    Energy Technology Data Exchange (ETDEWEB)

    Smith, David A. [Univ. of Colorado, Boulder, CO (United States)

    1998-11-01

    In November of 1993, mysterious signals recorded by a satellite-borne broadband VHF radio science experiment called Blackboard led to a completely unexpected discovery. Prior to launch of the ALEXIS satellite, it was thought that its secondary payload, Blackboard, would most often detect the radio emissions from lightning when its receiver was not overwhelmed by noise from narrowband communication carriers. Instead, the vast majority of events that triggered the instrument were isolated pairs of pulses that were one hundred times more energetic than normal thunderstorm electrical emissions. The events, which came to be known as TIPPs (for transionospheric pulse pairs), presented a true mystery to the geophysics community. At the time, it was not even known whether the events had natural or anthropogenic origins. After two and one half years of research into the unique signals, two ground-based receiver arrays in New Mexico first began to detect and record thunderstorm radio emissions that were consistent with the Blackboard observations. On two occasions, the ground-based systems and Blackboard even recorded emissions that were produced by the same exact events. From the ground based observations, it has been determined that TIPP events areproduced by brief, singular, isolated, intracloud electrical discharges that occur in intense regions of thunderstorms. These discharges have been dubbed CIDS, an acronym for compact intracloud discharges. During the summer of 1996, ground-based receiver arrays were used to record the electric field change signals and broadband HF emissions from hundreds of CIDS. Event timing that was accurate to within a few microseconds made possible the determination of source locations using methods of differential time of arrival. Ionospheric reflections of signals were recorded in addition to groundwave/line-of-sight signals and were used to determine accurate altitudes for the discharges. Twenty-four CIDS were recorded from three

  9. Evaluation of Personal Shields Used in Selected Radiology Departments

    Directory of Open Access Journals (Sweden)

    Mohsen Salmanvandi

    2015-05-01

    Full Text Available Introduction The purpose of this study was to evaluate personal shields in radiation departments of hospitals affiliated to Mashhad University of Medical Sciences. Materials and Methods First, the information related to 109 personal shields was recorded and evaluated by imaging equipment. Afterwards, the equivalent lead thickness (ELT of 62 personal shields was assessed, using dosimeter and standard lead layers at 100 kVp. Results In this study, 109 personal shields were assessed in terms of tears, holes and cracks. The results showed that 18 shields were damaged. Moreover, ELT was evaluated in 62 shields. As the results indicated, ELT was unacceptable in 8 personal shields and lower than expected in 9 shields. Conclusion According to the results, 16.5% of personal shields had defects (tears, holes and cracks and 13% of them were unacceptable in terms of ELT and needed to be replaced. Therefore, regular quality control of personal shields and evaluation of new shields are necessary at any radiation department.

  10. Radiation shielding analyses for JT-60SU

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Y. [Mitsubishi Heavy Industries Ltd., Tokyo (Japan); Neyatani, Y. [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Ishida, S.; Ashida, S.; Sawamura, H.; Tominaga, M.; Nishimura, K. [Computer Software Development Co., Ltd., Shinjuku, Tokyo (Japan)

    2000-03-01

    Radiation shielding analyses were done for JT-60 Super Upgrade (JT-60SU) of JAERI in Japan, and are reported here. From a viewpoint of the operation and the maintenance, it is important how accurately to evaluate the nuclear heating rate in the superconducting magnet and the activation of components around the vacuum vessel by irradiation of fusion neutrons. A boot-strapped calculation step was applied to the analyses to reduce the redundancy of the conservative in the results. The nuclear heating rate in the superconducting magnets and the maximum {gamma}-ray dose rate one month after shutdown in the cryostat were within the design limits of 2 mW/cc and 10 {mu}Sv/hr, respectively, in the nuclear shielding for a D-D neutron production rate of 1x10{sup 18} s{sup -1}. (author)

  11. EMC Test Report Electrodynamic Dust Shield

    Science.gov (United States)

    Carmody, Lynne M.; Boyette, Carl B.

    2014-01-01

    This report documents the Electromagnetic Interference E M I evaluation performed on the Electrodynamic Dust Shield (EDS) which is part of the MISSE-X System under the Electrostatics and Surface Physics Laboratory at Kennedy Space Center. Measurements are performed to document the emissions environment associated with the EDS units. The purpose of this report is to collect all information needed to reproduce the testing performed on the Electrodynamic Dust Shield units, document data gathered during testing, and present the results. This document presents information unique to the measurements performed on the Bioculture Express Rack payload; using test methods prepared to meet SSP 30238 requirements. It includes the information necessary to satisfy the needs of the customer per work order number 1037104. The information presented herein should only be used to meet the requirements for which it was prepared.

  12. Thermoforming plastic in lead shield construction.

    Science.gov (United States)

    Abrahams, M E; Chow, C H; Loyd, M D

    1989-09-01

    Radiation treatments using low energy X-rays or electrons frequently require a final field defining shield to be placed on the patient's skin. A custom made lead cut-out is used to provide a close fit to a particular patient's surface contours. We have developed a procedure which utilizes POLYFORM thermoplastic to obtain a negative mold of the patient instead of the traditional plaster bandage or dental impression gel. The Polyform is softened in warm water, molded carefully over the patient's surface, and is removed when "set" or hardened, usually within five minutes. Then lead sheet cut-outs can be formed within this negative. For shielding cut-outs requiring thicker lead sheet, a positive is made from dental stone using this Polyform negative. We have found this procedure to be neat, fast and comfortable for both patient and the dosimetrist.

  13. Thermoforming plastic in lead shield construction

    Energy Technology Data Exchange (ETDEWEB)

    Abrahams, M.E.; Chow, C.H.; Loyd, M.D. (Univ. of Texas Medical Branch, Galveston (USA))

    1989-09-01

    Radiation treatments using low energy X-rays or electrons frequently require a final field defining shield to be placed on the patient's skin. A custom made lead cut-out is used to provide a close fit to a particular patient's surface contours. We have developed a procedure which utilizes POLYFORM thermoplastic to obtain a negative mold of the patient instead of the traditional plaster bandage or dental impression gel. The Polyform is softened in warm water, molded carefully over the patient's surface, and is removed when set or hardened, usually within five minutes. Then lead sheet cut-outs can be formed within this negative. For shielding cut-outs requiring thicker lead sheet, a positive is made from dental stone using this Polyform negative. We have found this procedure to be neat, fast and comfortable for both patient and the dosimetrist.

  14. Grounding and shielding circuits and interference

    CERN Document Server

    Morrison, Ralph

    2016-01-01

    Applies basic field behavior in circuit design and demonstrates how it relates to grounding and shielding requirements and techniques in circuit design This book connects the fundamentals of electromagnetic theory to the problems of interference in all types of electronic design. The text covers power distribution in facilities, mixing of analog and digital circuitry, circuit board layout at high clock rates, and meeting radiation and susceptibility standards. The author examines the grounding and shielding requirements and techniques in circuit design and applies basic physics to circuit behavior. The sixth edition of this book has been updated with new material added throughout the chapters where appropriate. The presentation of the book has also been rearranged in order to reflect the current trends in the field.

  15. Summary of Self-compacting Concrete Workability

    OpenAIRE

    GUO Gui-xiang; Duan Hong-jun

    2015-01-01

    On the basis of a large number of domestic and foreign literature, situation and development of self-compacting concrete is introduced. Summary of the compacting theory of self-compacting concrete. And some of the factors affecting the workability of self-compacting concrete were discussed and summarized to a certain extent. Aims to further promote the application and research of self-compacting concrete

  16. New applications and developments in the neutron shielding

    Science.gov (United States)

    Uğur, Fatma Aysun

    2017-09-01

    Shielding neutrons involve three steps that are slowing neutrons, absorption of neutrons, and impregnation of gamma rays. Neutrons slow down with thermal energy by hydrogen, water, paraffin, plastic. Hydrogenated materials are also very effective for the absorption of neutrons. Gamma rays are produced by neutron (radiation) retention on the neutron shield, inelastic scattering, and degradation of activation products. If a source emits gamma rays at various energies, high-energy gamma rays sometimes specify shielding requirements. Multipurpose Materials for Neutron Shields; Concrete, especially with barium mixed in, can slow and absorb the neutrons, and shield the gamma rays. Plastic with boron is also a good multipurpose shielding material. In this study; new applications and developments in the area of neutron shielding will be discussed in terms of different materials.

  17. Compact magnetic confinement fusion: Spherical torus and compact torus

    Directory of Open Access Journals (Sweden)

    Zhe Gao

    2016-05-01

    Full Text Available The spherical torus (ST and compact torus (CT are two kinds of alternative magnetic confinement fusion concepts with compact geometry. The ST is actually a sub-category of tokamak with a low aspect ratio; while the CT is a toroidal magnetic configuration with a simply-connected geometry including spheromak and field reversed pinch. The ST and CT have potential advantages for ultimate fusion reactor; while at present they can also provide unique fusion science and technology contributions for mainstream fusion research. However, some critical scientific and technology issues should be extensively investigated.

  18. Deployable Debris Shields For Space Station

    Science.gov (United States)

    Christiansen, Eric L.; Cour-Palais, Burton G.; Crews, Jeanne

    1993-01-01

    Multilayer shields made of lightweight sheet materials deployed from proposed Space Station Freedom for additional protection against orbiting debris. Deployment mechanism attached at each location on exterior where extra protection needed. Equipment withdraws layer of material from storage in manner similar to unfurling sail or extending window shade. Number of layers deployed depends on required degree of protection, and could be as large as five.

  19. Neutron streaming studies along JET shielding penetrations

    OpenAIRE

    Stamatelatos Ion E.; Vasilopoulou Theodora; Batistoni Paola; Obryk Barbara; Popovichev Sergey; Naish Jonathan

    2017-01-01

    Neutronic benchmark experiments are carried out at JET aiming to assess the neutronic codes and data used in ITER analysis. Among other activities, experiments are performed in order to validate neutron streaming simulations along long penetrations in the JET shielding configuration. In this work, neutron streaming calculations along the JET personnel entrance maze are presented. Simulations were performed using the MCNP code for Deuterium-Deuterium and Deuterium- Tritium plasma sources. The ...

  20. Active shielding model for hyperbolic equations

    Science.gov (United States)

    Ryaben'kii, Victor S.; Utyuzhnikov, Sergei V.

    2006-12-01

    The problem of active shielding (AS) in application to hyperbolic equations is analysed. According to the problem, two domains effecting each other via distributed source terms are considered. It is required to implement additional sources nearby the common boundary of the domains in order to "isolate" one domain from the action of the other domain. It is important to note that the total field of the original sources is only known. In the paper, the theory of difference potentials is applied to the system of hyperbolic equations for the first time. It allows one to obtain a one-layer AS not requiring any additional computations. Local one-layer and two-layer AS sources are obtained for an arbitrary hyperbolic system. The solution does not require either the knowledge of the Green's function or the specific characteristics of the sources and medium. The optimal one-layer AS solution is derived in the case of free space. In particular, the results are applicable to the system of acoustics equations. The questions related to a practical realization including the mutual situation of the primary and secondary sources, as well as the measurement point, are discussed. The active noise shielding can be realized via a one-layer source term requiring the measurements only at one layer nearby the domain shielded.

  1. Active Muon Shield - Preliminary Design Report

    CERN Document Server

    Bayliss, Victoria; Rawlings, T

    2015-01-01

    This report summarises the initial design study which was carried out for the SHiP magnetic muon shield – which is proposed to consist of a 40m beamline of seven magnets generating a 1.8T By field over defined cross-section. This is intended to sweep unwanted muons off the beamline to prevent them reaching the detector. The magnetic shield is an alternative to a passive tungsten shield. This work was carried out in three sections. Initially the magnets were considered in isolation to establish whether they were theoretically feasible to build and the impact of the iron yoke shape and material was considered. Next the beamline was considered as a whole; this included issues such as the impact of neighbouring magnets and the hadrons stopper, and also building a model of the complete beamline whose magnetic fields could be exported for use in particle modelling. Finally, some consideration was given to the manufacture and operational issues, including costs.

  2. Shadow banking, relationship banking, and the economics of depression

    Directory of Open Access Journals (Sweden)

    Antonio Bianco

    2015-12-01

    Full Text Available The paper explores whether a theory of banks doing ‘finance through money creation’ implies a reconsideration of demand-side macro theory as well. To this aim, a simple methodological accounting model of the influence of financial markets over the real economy is presented. The model allows a tidy comparison of relationship and shadow banking, interpreted as alternative schemes of liquidity (not credit risk management. The model emphasizes the interdependencies in entrepreneurs’ animal spirits, liquidity risk management schemes adopted by financial institutions, and effective demand of households. The underlying idea is that fluctuations in the composition of property incomes trigger fluctuations in non-financial investment that, in turn, drive fluctuations in spending. The article finds that both relationship and shadow banking must have a pro-cyclical impact, and differences are essentially based on different liquidity risk management aggregate cost functions. The model developed here suggests that securitisation does not per se affect the financial sustainability of the growth process, but regulatory measures aimed at checking predatory lending and re-securitisation activities are needed to avoid possible adverse impacts on animal spirits. JEL codes: E44, G20, O16.

  3. Racing the Moon’s shadow with Concorde 001

    CERN Document Server

    Léna, Pierre

    2015-01-01

    This is the unique story of  observing a total solar exlipse for no less than 74 consecutive minutes. On the summer morning of June 30, 1973, the Sun rises on the Canary Islands. But it is strangely indented by the Moon. The eclipse of the century has just begun. From the west, the lunar shadow rushes to the African coast at a velocity of over 2000 kilometers per hour. Astronomers on the ground will enjoy seven short minutes of total eclipse to study the solar corona - too short for Pierre Lena and seven scientists who board the Concorde 001 prototype, an extraordinary plane to become the first commercial supersonic aircraft. With André Turcat as chief pilot and a crew of five, at 17000 m altitude, the aircraft remains in the lunar shadow for 74 minutes, a record time of scientific observations not yet beaten and allowing for exceptional measurements. Science, technology, aviation and history combine in the story of a unique human adventure aboard a legendary aircraft, illustrated with a rich and original ...

  4. Sub-shot-noise shadow sensing with quantum correlations.

    Science.gov (United States)

    Toninelli, Ermes; Edgar, Matthew P; Moreau, Paul-Antoine; Gibson, Graham M; Hammond, Giles D; Padgett, Miles J

    2017-09-04

    The quantised nature of the electromagnetic field sets the classical limit to the sensitivity of position measurements. However, techniques based on the properties of quantum states can be exploited to accurately measure the relative displacement of a physical object beyond this classical limit. In this work, we use a simple scheme based on the split-detection of quantum correlations to measure the position of a shadow at the single-photon light level, with a precision that exceeds the shot-noise limit. This result is obtained by analysing the correlated signals of bi-photon pairs, created in parametric downconversion and detected by an electron multiplying CCD (EMCCD) camera employed as a split-detector. By comparing the measured statistics of spatially anticorrelated and uncorrelated photons we were able to observe a significant noise reduction corresponding to an improvement in position sensitivity of up to 17% (0.8dB). Our straightforward approach to sub-shot-noise position measurement is compatible with conventional shadow-sensing techniques based on the split-detection of light-fields, and yields an improvement that scales favourably with the detector's quantum efficiency.

  5. Improving Shadow Suppression for Illumination Robust Face Recognition

    KAUST Repository

    Zhang, Wuming

    2017-10-13

    2D face analysis techniques, such as face landmarking, face recognition and face verification, are reasonably dependent on illumination conditions which are usually uncontrolled and unpredictable in the real world. An illumination robust preprocessing method thus remains a significant challenge in reliable face analysis. In this paper we propose a novel approach for improving lighting normalization through building the underlying reflectance model which characterizes interactions between skin surface, lighting source and camera sensor, and elaborates the formation of face color appearance. Specifically, the proposed illumination processing pipeline enables the generation of Chromaticity Intrinsic Image (CII) in a log chromaticity space which is robust to illumination variations. Moreover, as an advantage over most prevailing methods, a photo-realistic color face image is subsequently reconstructed which eliminates a wide variety of shadows whilst retaining the color information and identity details. Experimental results under different scenarios and using various face databases show the effectiveness of the proposed approach to deal with lighting variations, including both soft and hard shadows, in face recognition.

  6. Performance Analysis of CDMA Wireless Sensor Networks in Shadowed Environment

    Directory of Open Access Journals (Sweden)

    U. DATTA

    2010-07-01

    Full Text Available This paper evaluates the performance of a CDMA based wireless sensor networks (WSN with layered architecture in terms of QoS like outage probability, bit error rate (BER, throughput, and delay, considering correlation amongst interferers in shadowed environment. Energy consumption for successful delivery of information is also evaluated at different channel conditions. Two kinds of interference namely multiple access interference (MAI and node interference (NI are considered and an infinite ARQ is assumed at link layer between a sending node and sink till successful transmission of packetized data. An appropriate analytical model of interference considering correlation amongst interferers, power control error and shadowing is developed for evaluating bit error rate (BER, packet error rate (PER, average number of retransmission for successful delivery of information, throughput, and delay in a single hop communication. A simple energy model is used for evaluating the consumption of energy for successful delivery of information between source and sink. We also evaluate the sink capacity of wireless CDMA sensor networks considering a threshold BER. Sink capacity is defined as the maximum number of sensor nodes transmitting concurrently to the sink and located within one hop layer. The impact of NI on the sink capacity is also indicated. The effects of node density, correlation amongst interferers and power control error (pce on performance of WSN are investigated. Analytical results are supported by simulation results.

  7. Tomographic Particle Image Velocimetry using Smartphones and Colored Shadows.

    Science.gov (United States)

    Aguirre-Pablo, Andres A; Alarfaj, Meshal K; Li, Er Qiang; Hernández-Sánchez, J F; Thoroddsen, Sigurdur T

    2017-06-16

    We demonstrate the viability of using four low-cost smartphone cameras to perform Tomographic PIV. We use colored shadows to imprint two or three different time-steps on the same image. The back-lighting is accomplished with three sets of differently-colored pulsed LEDs. Each set of Red, Green & Blue LEDs is shone on a diffuser screen facing each of the cameras. We thereby record the RGB-colored shadows of opaque suspended particles, rather than the conventionally used scattered light. We subsequently separate the RGB color channels, to represent the separate times, with preprocessing to minimize noise and cross-talk. We use commercially available Tomo-PIV software for the calibration, 3-D particle reconstruction and particle-field correlations, to obtain all three velocity components in a volume. Acceleration estimations can be done thanks to the triple pulse illumination. Our test flow is a vortex ring produced by forcing flow through a circular orifice, using a flexible membrane, which is driven by a pressurized air pulse. Our system is compared to a commercial stereoscopic PIV system for error estimations. We believe this proof of concept experiment will make this technique available for education, industry and scientists for a fraction of the hardware cost needed for traditional Tomo-PIV.

  8. Leaking privacy and shadow profiles in online social networks.

    Science.gov (United States)

    Garcia, David

    2017-08-01

    Social interaction and data integration in the digital society can affect the control that individuals have on their privacy. Social networking sites can access data from other services, including user contact lists where nonusers are listed too. Although most research on online privacy has focused on inference of personal information of users, this data integration poses the question of whether it is possible to predict personal information of nonusers. This article tests the shadow profile hypothesis, which postulates that the data given by the users of an online service predict personal information of nonusers. Using data from a disappeared social networking site, we perform a historical audit to evaluate whether personal data of nonusers could have been predicted with the personal data and contact lists shared by the users of the site. We analyze personal information of sexual orientation and relationship status, which follow regular mixing patterns in the social network. Going back in time over the growth of the network, we measure predictor performance as a function of network size and tendency of users to disclose their contact lists. This article presents robust evidence supporting the shadow profile hypothesis and reveals a multiplicative effect of network size and disclosure tendencies that accelerates the performance of predictors. These results call for new privacy paradigms that take into account the fact that individual privacy decisions do not happen in isolation and are mediated by the decisions of others.

  9. Verbal shadowing and visual interference in spatial memory.

    Science.gov (United States)

    Meilinger, Tobias; Bülthoff, Heinrich H

    2013-01-01

    Spatial memory is thought to be organized along experienced views and allocentric reference axes. Memory access from different perspectives typically yields V-patterns for egocentric encoding (monotonic decline in performance along with the angular deviation from the experienced perspectives) and W-patterns for axes encoding (better performance along parallel and orthogonal perspectives than along oblique perspectives). We showed that learning an object array with a verbal secondary task reduced W-patterns compared with learning without verbal shadowing. This suggests that axes encoding happened in a verbal format; for example, by rows and columns. Alternatively, general cognitive load from the secondary task prevented memorizing relative to a spatial axis. Independent of encoding, pointing with a surrounding room visible yielded stronger W-patterns compared with pointing with no room visible. This suggests that the visible room geometry interfered with the memorized room geometry. With verbal shadowing and without visual interference only V-patterns remained; otherwise, V- and W-patterns were combined. Verbal encoding and visual interference explain when W-patterns can be expected alongside V-patterns and thus can help in resolving different performance patterns in a wide range of experiments.

  10. Tomographic Particle Image Velocimetry using Smartphones and Colored Shadows

    KAUST Repository

    Aguirre-Pablo, Andres A.

    2017-06-12

    We demonstrate the viability of using four low-cost smartphone cameras to perform Tomographic PIV. We use colored shadows to imprint two or three different time-steps on the same image. The back-lighting is accomplished with three sets of differently-colored pulsed LEDs. Each set of Red, Green & Blue LEDs is shone on a diffuser screen facing each of the cameras. We thereby record the RGB-colored shadows of opaque suspended particles, rather than the conventionally used scattered light. We subsequently separate the RGB color channels, to represent the separate times, with preprocessing to minimize noise and cross-talk. We use commercially available Tomo-PIV software for the calibration, 3-D particle reconstruction and particle-field correlations, to obtain all three velocity components in a volume. Acceleration estimations can be done thanks to the triple pulse illumination. Our test flow is a vortex ring produced by forcing flow through a circular orifice, using a flexible membrane, which is driven by a pressurized air pulse. Our system is compared to a commercial stereoscopic PIV system for error estimations. We believe this proof of concept experiment will make this technique available for education, industry and scientists for a fraction of the hardware cost needed for traditional Tomo-PIV.

  11. Tomographic Particle Image Velocimetry Using Colored Shadow Imaging

    KAUST Repository

    Alarfaj, Meshal K.

    2016-02-01

    Tomographic Particle Image Velocimetry Using Colored Shadow Imaging by Meshal K Alarfaj, Master of Science King Abdullah University of Science & Technology, 2015 Tomographic Particle image velocimetry (PIV) is a recent PIV method capable of reconstructing the full 3D velocity field of complex flows, within a 3-D volume. For nearly the last decade, it has become the most powerful tool for study of turbulent velocity fields and promises great advancements in the study of fluid mechanics. Among the early published studies, a good number of researches have suggested enhancements and optimizations of different aspects of this technique to improve the effectiveness. One major aspect, which is the core of the present work, is related to reducing the cost of the Tomographic PIV setup. In this thesis, we attempt to reduce this cost by using an experimental setup exploiting 4 commercial digital still cameras in combination with low-cost Light emitting diodes (LEDs). We use two different colors to distinguish the two light pulses. By using colored shadows with red and green LEDs, we can identify the particle locations within the measurement volume, at the two different times, thereby allowing calculation of the velocities. The present work tests this technique on the flows patterns of a jet ejected from a tube in a water tank. Results from the images processing are presented and challenges discussed.

  12. An attenuation Layer for Electromagnetic Shielding in X- Band Frequency

    Directory of Open Access Journals (Sweden)

    vida Zaroushani

    2015-06-01

    Full Text Available Uncontrolled exposure to X-band frequency leads to health damage. One of the principles of radiation protection is shielding. But, conventional shielding materials have disadvantages. Therefore, studies of novel materials, as an alternative to conventional shielding materials, are required to obtain new electromagnetic shielding material. Therefore, this study investigated the electromagnetic shielding of two component epoxy thermosetting resin for the X - band frequency with workplace approach. Two components of epoxy resin mixed according to manufacturing instruction with the weight ratio that was 100:10 .Epoxy plates fabricated in three different thicknesses (2, 4 and 6mm and shielding effectiveness measured by Vector Network Analyzer. Then, shielding effectiveness measured by the scattering parameters.The results showed that 6mm thickness of epoxy had the highest and 2mm had the lowest average of shielding effectiveness in X-band frequency that is 4.48 and 1.9 dB, respectively. Also, shielding effectiveness increased by increasing the thickness. But this increasing is useful up to 4mm. Percentage shielding effectiveness of attenuation for 6, 4 and 2mm thicknesses is 64.35%, 63.31% and 35.40%. Also, attenuation values for 4mm and 6mm thicknesses at 8.53 GHz and 8.52 GHz frequency are 77.15% and 82.95%, respectively, and can be used as favourite shields for the above frequency. 4mm-Epoxy is a suitable candidate for shielding application in X-band frequency range but, in the lower section, 6mm thickness is recommended. Finely, the shielding matrix can be used for selecting the proper thickness for electromagnetic shielding in X- Band frequency.

  13. Enhancing Wave Energy Competitiveness through Co-Located Wind and Wave Energy Farms. A Review on the Shadow Effect

    Directory of Open Access Journals (Sweden)

    Sharay Astariz

    2015-07-01

    Full Text Available Wave energy is one of the most promising alternatives to fossil fuels due to the enormous available resource; however, its development may be slowed as it is often regarded as uneconomical. The largest cost reductions are expected to be obtained through economies of scale and technological progress. In this sense, the incorporation of wave energy systems into offshore wind energy farms is an opportunity to foster the development of wave energy. The synergies between both renewables can be realised through these co-located energy farms and, thus, some challenges of offshore wind energy can be met. Among them, this paper focuses on the longer non-operational periods of offshore wind turbines—relative to their onshore counterparts—typically caused by delays in maintenance due to the harsh marine conditions. Co-located wave energy converters would act as a barrier extracting energy from the waves and resulting in a shielding effect over the wind farm. On this basis, the aim of this paper is to analyse wave energy economics in a holistic way, as well as the synergies between wave and offshore wind energy, focusing on the shadow effect and the associated increase in the accessibility to the wind turbines.

  14. The United Nations Global Compact

    DEFF Research Database (Denmark)

    Rasche, Andreas; Waddock, Sandra; McIntosh, Malcolm

    2013-01-01

    This article reviews the interdisciplinary literature on the UN Global Compact. The review identifies three research perspectives, which scholars have used to study the UN Global Compact so far: a historical perspective discussing the Global Compact in the context of UN-business relations......, an operational perspective discussing the composition and impact of its participants, as well as a governance perspective discussing the constraints and opportunities of the initiative as an institutionalized arena for addressing global governance gaps. The authors contrast these three perspectives and identify...... key empirical as well as conceptual scholarly contributions. The remainder of this article contains focused summaries of the articles selected for this Special Issue. All articles are introduced and evaluated against the background of the three research perspectives....

  15. Compaction Stress in Fine Powders

    Energy Technology Data Exchange (ETDEWEB)

    Hurd, A.J.; Kenkre, V.M.; Pease, E.A.; Scott, J.E.

    1999-04-01

    A vexing feature in granular materials compaction is density extrema interior to a compacted shape. Such inhomogeneities can lead to weaknesses and loss of dimensional control in ceramic parts, unpredictable dissolution of pharmaceuticals, and undesirable stress concentration in load-bearing soil. As an example, the centerline density in a cylindrical compact often does not decrease monotonically from the pressure source but exhibits local maxima and minima. Two lines of thought in the literature predict, respectively, diffusive and wavelike propagation of stress. Here, a general memory function approach has been formulated that unifies these previous treatments as special cases; by analyzing a convenient intermediate case, the telegrapher's equation, one sees that local density maxima arise via semidiffusive stress waves reflecting from the die walls and adding constructively at the centerline.

  16. Discursive Shadowing in Linguistic Ethnography. Situated Practices and Circulating Discourses in Multilingual Schools

    Science.gov (United States)

    Dewilde, Joke; Creese, Angela

    2016-01-01

    We consider discursive shadowing as methodology in linguistic ethnography and how it refines our analyses of participants' situated practices. In addition to the constant and extended company the researcher and key participant keep with one another in the field, shadowing in a linguistic ethnographic approach includes the ubiquitous…

  17. Accurate moving cast shadow suppression based on local color constancy detection.

    Science.gov (United States)

    Amato, Ariel; Mozerov, Mikhail G; Bagdanov, Andrew D; Gonzàlez, Jordi

    2011-10-01

    This paper describes a novel framework for detection and suppression of properly shadowed regions for most possible scenarios occurring in real video sequences. Our approach requires no prior knowledge about the scene, nor is it restricted to specific scene structures. Furthermore, the technique can detect both achromatic and chromatic shadows even in the presence of camouflage that occurs when foreground regions are very similar in color to shadowed regions. The method exploits local color constancy properties due to reflectance suppression over shadowed regions. To detect shadowed regions in a scene, the values of the background image are divided by values of the current frame in the RGB color space. We show how this luminance ratio can be used to identify segments with low gradient constancy, which in turn distinguish shadows from foreground. Experimental results on a collection of publicly available datasets illustrate the superior performance of our method compared with the most sophisticated, state-of-the-art shadow detection algorithms. These results show that our approach is robust and accurate over a broad range of shadow types and challenging video conditions. © 2011 IEEE

  18. Shadow enhancement in synthetic aperture sonar imagery for improved target classification

    NARCIS (Netherlands)

    Sabel, J.C.; Groen, J.; Quesson, B.A.J.

    2005-01-01

    The acoustic shadow of a target is a strong classification clue in naval mine hunting. A shadow of bottom targets appears at relatively short ranges (≤ about 200 m) in high resolution images from sidescan or synthetic aperture sonar (SAS), against a background of sea floor reverberation. In SAS

  19. Work-Shadowing as a Process for Facilitating Leadership Succession in Primary Schools

    Science.gov (United States)

    Simkins, Tim; Close, Paul; Smith, Robin

    2009-01-01

    Work-shadowing is an under-researched aspect of leadership development. This paper places workshadowing in the broader context of responses to the challenges of managing leadership succession in schools, drawing on an evaluation of a pilot shadowing programme for aspiring primary headteachers. The paper identifies a number of key themes in…

  20. Qualitative Shadowing as a Research Methodology for Exploring Early Childhood Leadership in Practice

    Science.gov (United States)

    Bøe, Marit; Hognestad, Karin; Waniganayake, Manjula

    2017-01-01

    This article explores qualitative shadowing as an interpretivist methodology, and explains how two researchers participating simultaneously in data collection using a video recorder, contextual interviews and video-stimulated recall interviews, conducted a qualitative shadowing study at six early childhood centres in Norway. This paper emerged…

  1. Implementing content constraints in alpha-stratified adaptive using a shadow test approach

    NARCIS (Netherlands)

    van der Linden, Willem J.; Chang, Hua-Hua

    2003-01-01

    The methods of alpha-stratified adaptive testing and constrained adaptive testing with shadow tests are combined. The advantages are twofold: First, application of the shadow test approach allows the implementation of any type of constraint on item selection in alpha-stratified adaptive testing.

  2. Implementing content constraints in alpha-stratified adaptive testing using a shadow test approach

    NARCIS (Netherlands)

    van der Linden, Willem J.; Chang, Hua-Hua

    2001-01-01

    The methods of alpha-stratified adaptive testing and constrained adaptive testing with shadow tests are combined in this study. The advantages are twofold. First, application of the shadow test allows the researcher to implement any type of constraint on item selection in alpha-stratified adaptive

  3. The Job Shadow Assignment: Career Perceptions in Hospitality, Recreation and Tourism

    Science.gov (United States)

    Padron, Thomas C.; Fortune, Mary F.; Spielman, Melany; Tjoei, Sylvie

    2017-01-01

    The job shadow study measured student career perceptions related to hospitality, recreation and tourism (HRT) and instructional mode (face-to-face (F2F), hybrid, and online). College students self-selecting into three different course modalities taught by the same instructor job shadowed HRT professionals by using Internet and F2F interviews. The…

  4. Interplay of Internal and External Representations: Students' Drawings and Textual Explanations about Shadow Phenomena

    Science.gov (United States)

    Valanides, Nicos; Efthymiou, Irene; Angeli, Charoula

    2013-01-01

    Fifty-six third-year kindergarten student teachers (KTS) were presented with an experimental setting for investigating shadow phenomena. Prior to performing any specific experiment, KTS were asked to externalize their ideas about shadow phenomena corresponding to different configurations of the experimental setting through the use of drawings…

  5. The Link between Speech Perception and Production Is Phonological and Abstract: Evidence from the Shadowing Task

    Science.gov (United States)

    Mitterer, Holger; Ernestus, Mirjam

    2008-01-01

    This study reports a shadowing experiment, in which one has to repeat a speech stimulus as fast as possible. We tested claims about a direct link between perception and production based on speech gestures, and obtained two types of counterevidence. First, shadowing is not slowed down by a gestural mismatch between stimulus and response. Second,…

  6. Shadow Education in Spain: Examining Social Inequalities through the Analysis of PISA Results

    Science.gov (United States)

    Runte-Geidel, Ariadne; Marzo, Pedro Femia

    2015-01-01

    This article examines the use of shadow education by students of compulsory secondary education in Spain over the period 2000-2010. The study identifies the proportion of the student population that uses this type of education and examines how the use of shadow education has evolved during this period. Data was drawn from the student questionnaire…

  7. SU-E-T-200: IBA ProteusOne Compact Proton Therapy System Radiation Survey Results

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, J; Syh, J; Syh, J; White, M; Patel, B; Song, X; Wu, H [Willis-Knighton Cancer Center, Shreveport, LA (United States)

    2014-06-01

    Purpose: This study summarizes the results of an initial radiation survey of the Willis-Knighton Cancer Center in Shreveport, Louisiana. The facility houses an IBA ProteusOne compact single room proton therapy unit coupled with a C230 cyclotron that operates at a maximum energy of 230 MeV. Methods: A calibrated survey meter was used for the photon measurements to obtain reliable results. A neutron detector was used as the measuring instrument for neutrons. The locations of the survey and measurements were planned carefully in order to get a proper evaluation of the facility shielding configuration. The walls, ceiling, vault entrance, and the adjacent environment were each surveyed with suitable measurement instruments. A total of 22 locations were chosen for radiation survey. Dose equivalent values were calculated for both the photon and the neutron radiation using measured data. Results: All measured dose values are presented in millisievert per year. The highest dose measured at the vault entrance is 0.34 mSv/year. A dedicated shielding door was not present at the time of the measurement. The vault entrance area is considered as a controlled area. The shielding design goals are not to exceed 5 mSv/year for the controlled area and 1 mSv/year the uncontrolled area. The total combined neutron and photon dose equivalent values were found to be compliant with the Louisiana Department of Environmental Quality radiation protection regulatory codes. Conclusion: In our efforts to evaluate the radiation levels at the Willis-Knighton Cancer Center proton treatment facility, we have found that all the measured values of the radiation shielding are below the critical radiation limits per year. Since the total dose measured at the vault entrance is below the shielding design goal, a shielding door is not required at this proton treatment vault.

  8. Optimization of a partially non-magnetic primary radiation shielding for the triple-axis spectrometer PANDA at the Munich high-flux reactor FRM-II

    CERN Document Server

    Pyka, N M; Rogov, A

    2002-01-01

    Monte Carlo simulations have been used to optimize the monochromator shielding of the polarized cold-neutron triple-axis spectrometer PANDA at the Munich high-flux reactor FRM-II. By using the Monte Carlo program MCNP-4B, the density of the total spectrum of incoming neutrons and gamma radiation from the beam tube SR-2 has been determined during the three-dimensional diffusion process in different types of heavy concrete and other absorbing material. Special attention has been paid to build a compact and highly efficient shielding, partially non-magnetic, with a total biological radiation dose of less than 10 mu Sv/h at its outsides. Especially considered was the construction of an albedo reducer, which serves to reduce the background in the experiment outside the shielding. (orig.)

  9. Professional Windows Embedded Compact 7

    CERN Document Server

    Phung, Samuel; Joubert, Thierry; Hall, Mike

    2011-01-01

    Learn to program an array of customized devices and solutions As a compact, highly efficient, scalable operating system, Windows Embedded Compact 7 (WEC7) is one of the best options for developing a new generation of network-enabled, media-rich, and service-oriented devices. This in-depth resource takes you through the benefits and capabilities of WEC7 so that you can start using this performance development platform today. Divided into several major sections, the book begins with an introduction and then moves on to coverage of OS design, application development, advanced application developm

  10. Compact accelerator for medical therapy

    Energy Technology Data Exchange (ETDEWEB)

    Caporaso, George J.; Chen, Yu-Jiuan; Hawkins, Steven A.; Sampayan, Stephen E.; Paul, Arthur C.

    2010-05-04

    A compact accelerator system having an integrated particle generator-linear accelerator with a compact, small-scale construction capable of producing an energetic (.about.70-250 MeV) proton beam or other nuclei and transporting the beam direction to a medical therapy patient without the need for bending magnets or other hardware often required for remote beam transport. The integrated particle generator-accelerator is actuable as a unitary body on a support structure to enable scanning of a particle beam by direction actuation of the particle generator-accelerator.

  11. a Novel Method of Cloud and Shadow Extraction with Multi-Temporal LANDSAT8 Oli Images

    Science.gov (United States)

    Ni, Y.; He, G.; Jiang, W.

    2017-09-01

    Cloud and Shadow removal is a significant step in remote sensing image process. As we all know, the ground object coverage type of the same area of the remote sensing image has little change in the short term. But for cloud and shadow coverage areas, the ground object coverage type has large change. Therefore, according to the difference between the two Landsat / OLI images caused by changes in the cover, this paper presents a method of extracting clouds and shadows based on differences in luminance values. This method selects two thresholds for the difference of brightness values, and extracts the clouds and shadows respectively, and validates them with random point method, which can obtain high precision of extracting cloud and shadow and satisfy the actual application needs.

  12. Shadow Probability of Detection and False Alarm for Median-Filtered SAR Imagery

    Energy Technology Data Exchange (ETDEWEB)

    Raynal, Ann Marie [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). ISR Analysis and Applications Dept.; Doerry, Armin Walter [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). ISR Mission Engineering Dept.; Miller, John A. [General Atomics Aeronautical Systems, Inc., San Diego, CA (United States). Mission Systems; Bishop, Edward E. [General Atomics Aeronautical Systems, Inc., San Diego, CA (United States). Mission Systems; Horndt, Volker [General Atomics Aeronautical Systems, Inc., San Diego, CA (United States). Mission Systems

    2014-06-01

    Median filtering reduces speckle in synthetic aperture radar (SAR) imagery while preserving edges, at the expense of coarsening the resolution, by replacing the center pixel of a sliding window by the median value. For shadow detection, this approach helps distinguish shadows from clutter more easily, while preserving shadow shape delineations. However, the nonlinear operation alters the shadow and clutter distributions and statistics, which must be taken into consideration when computing probability of detection and false alarm metrics. Depending on system parameters, median filtering can improve probability of detection and false alarm by orders of magnitude. Herein, we examine shadow probability of detection and false alarm in a homogeneous, ideal clutter background after median filter post-processing. Some comments on multi-look processing effects with and without median filtering are also made.

  13. Spacecraft’s attitude prediction: solar radiation torque and the Earth’s shadow

    Science.gov (United States)

    Zanardi, M. C.; Vilhena de Moraes, R.; Cabette, R. E. S.; Garcia, R. V.

    A semi-analytical approach is proposed to study the rotational motion of an artificial satellite, under the influence of torque due to the solar radiation pressure, and taking into account the influence of Earth's shadow. Using Andoyer variables the equations for the rotational motion are presented in extended Hamiltonian form. In order to get a solution for the state variables close to an actual motion, the considered model for the shadow function takes into account physical and geometric factors and three specific regions: shadow, penumbra and full light. A mapping for the shadow function is proposed and a semi-analytical process is applied. When the satellite is totally illuminated or it is inside the penumbra, a known analytical solution is used to compute the satellite's attitude. A numerical simulation shows, when the penumbra region is included, the attenuation of the rotational motion during the transition from the shadow to the illuminate region and vice versa.

  14. Compaction dynamics of crunchy granular material

    Directory of Open Access Journals (Sweden)

    Guillard François

    2017-01-01

    Full Text Available Compaction of brittle porous material leads to a wide variety of densification patterns. Static compaction bands occurs naturally in rocks or bones, and have important consequences in industry for the manufacturing of powder tablets or metallic foams for example. Recently, oscillatory compaction bands have been observed in brittle porous media like snow or cereals. We will discuss the great variety of densification patterns arising during the compaction of puffed rice, including erratic compaction at low velocity, one or several travelling compaction bands at medium velocity and homogeneous compaction at larger velocity. The conditions of existence of each pattern are studied thanks to a numerical spring lattice model undergoing breakage and is mapped to the phase diagram of the patterns based on dimensionless characteristic quantities. This also allows to rationalise the evolution of the compaction behaviour during a single test. Finally, the localisation of compaction bands is linked to the strain rate sensitivity of the material.

  15. Compaction dynamics of crunchy granular material

    Science.gov (United States)

    Guillard, François; Golshan, Pouya; Shen, Luming; Valdès, Julio R.; Einav, Itai

    2017-06-01

    Compaction of brittle porous material leads to a wide variety of densification patterns. Static compaction bands occurs naturally in rocks or bones, and have important consequences in industry for the manufacturing of powder tablets or metallic foams for example. Recently, oscillatory compaction bands have been observed in brittle porous media like snow or cereals. We will discuss the great variety of densification patterns arising during the compaction of puffed rice, including erratic compaction at low velocity, one or several travelling compaction bands at medium velocity and homogeneous compaction at larger velocity. The conditions of existence of each pattern are studied thanks to a numerical spring lattice model undergoing breakage and is mapped to the phase diagram of the patterns based on dimensionless characteristic quantities. This also allows to rationalise the evolution of the compaction behaviour during a single test. Finally, the localisation of compaction bands is linked to the strain rate sensitivity of the material.

  16. SU-F-I-71: Fetal Protection During Fluoroscopy: To Shield Or Not to Shield?

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, S; Vanderhoek, M [Henry Ford Health System, Detroit, MI (United States)

    2016-06-15

    Purpose: Lead aprons are routinely used to shield the fetus from radiation during fluoroscopically guided interventions (FGI) involving pregnant patients. When placed in the primary beam, lead aprons often reduce image quality and increase fluoroscopic radiation output, which can adversely affect fetal dose. The purpose of this work is to identify an effective and practical method to reduce fetal dose without affecting image quality. Methods: A pregnant patient equivalent abdominal phantom is set on the table along with an image quality test object (CIRS model 903) representing patient anatomy of interest. An ion chamber is positioned at the x-ray beam entrance to the phantom, which is used to estimate the relative fetal dose. For three protective methods, image quality and fetal dose measurements are compared to baseline (no protection):1. Lead apron shielding the entire abdomen; 2. Lead apron shielding part of the abdomen, including the fetus; 3. Narrow collimation such that fetus is excluded from the primary beam. Results: With lead shielding the entire abdomen, the dose is reduced by 80% relative to baseline along with a drastic deterioration of image quality. With lead shielding only the fetus, the dose is reduced by 65% along with complete preservation of image quality, since the image quality test object is not shielded. However, narrow collimation results in 90% dose reduction and a slight improvement of image quality relative to baseline. Conclusion: The use of narrow collimation to protect the fetus during FGI is a simple and highly effective method that simultaneously reduces fetal dose and maintains sufficient image quality. Lead aprons are not as effective at fetal dose reduction, and if placed improperly, they can severely degrade image quality. Future work aims to investigate a wider variety of fluoroscopy systems to confirm these results across many different system geometries.

  17. Three-dimensional interconnect technology for ultra-compact MMICs

    Science.gov (United States)

    Hirano, Makoto; Nishikawa, Kenjiro; Toyoda, Ichihiko; Aoyama, Shinji; Sugitani, Suehiro; Yamasaki, Kimiyoshi

    1997-10-01

    A novel interconnect technology was reviewed, which was developed for three-dimensional (3-D) ultra-compact MMICs. Using O 2/He RIE for the through hole and trench formation of a thick polyimide insulator layer, low-current electroplating for gold sidewall formation in the through-holes and the trenches, and ion-milling with WSiN metal stopper for gold patterning, a complete three-dimensional metal interconnection structure was built. We call this fabrication method as folded metal interconnection technology with thick insulator(FMIT). The 3-D interconnection structure involves vertical interconnection elements such as a wall-like microwire for shielding or coupling, and a pillar-like via-connection with multi-leveled planar interconnections in a 10-μm-thick polyimide matrix on an IC chip. The structure provides many passive functional elements and circuits in an extremely small area. This technology stages the next-generation of ultra-compact MMICs by offering the circuit designers great design flexibility and higher integration of circuits.

  18. Compact Circuit Preprocesses Accelerometer Output

    Science.gov (United States)

    Bozeman, Richard J., Jr.

    1993-01-01

    Compact electronic circuit transfers dc power to, and preprocesses ac output of, accelerometer and associated preamplifier. Incorporated into accelerometer case during initial fabrication or retrofit onto commercial accelerometer. Made of commercial integrated circuits and other conventional components; made smaller by use of micrologic and surface-mount technology.

  19. A compact molecular beam machine

    NARCIS (Netherlands)

    Jansen, P.; Chandler, D.W.; Strecker, K.E.

    2009-01-01

    We have developed a compact, low cost, modular, crossed molecular beam machine. The new apparatus utilizes several technological advancements in molecular beams valves, ion detection, and vacuum pumping to reduce the size, cost, and complexity of a molecular beam apparatus. We apply these

  20. Boundaries of flat compact surfaces

    DEFF Research Database (Denmark)

    Røgen, Peter

    1999-01-01

    type. The number of $3$-singular points (points of zero curvature or if not then of zero torsion) on the boundary of a flat immersed compact surface is greater than or equal to twice the absolute value of the Euler characteristic of the surface. A set of necessary and, in a weakened sense, sufficient...

  1. Compactness in fuzzy function spaces

    African Journals Online (AJOL)

    In [3] we defined a notion of compactness in FCS, the category of fuzzy convergence spaces as defined by Lowen/Lowen/Wuyts [8]. In their paper the latter also introduced a fuzzy convergence structure c-lim for fuzzy function spaces thus proving that FCS is a topological quasitopos. In this paper we start the investigation of ...

  2. Decompounding on compact Lie groups

    CERN Document Server

    Said, Salem; Bihan, Nicolas Le; Manton, Jonathan H

    2009-01-01

    Noncommutative harmonic analysis is used to solve a nonparametric estimation problem stated in terms of compound Poisson processes on compact Lie groups. This problem of decompounding is a generalization of a similar classical problem. The proposed solution is based on a char- acteristic function method. The treated problem is important to recent models of the physical inverse problem of multiple scattering.

  3. Dynamic compaction of ceramic powders

    Energy Technology Data Exchange (ETDEWEB)

    Cline, C.F.

    1982-06-10

    Dynamic consolidation is a technique for densifying powder ensembles to near theoretical with or without external application of heat. The technique itself is simple: the confined powder, initially at a green density of approx. 50% encounters a high pressure shock wave which exceeds the yield strength and densifies as the wave proceeds through the compact. The time scales and pressure range from 1-10's of microseconds and 10-100's of kilobars (10 Kb = 1 GPa). The short time scale of the pressure pulse during the compaction stage inhibits kinetic processes which have longer time constants. The pressure pulse can be delivered to the green compact by a number of techniques, i.e. high explosive, projectile. The methods differ in the degree that one can control the amplitude, duration, and nature of the pressure pulse. The lecture compares powders compacted by explosive and light gas guns and when possible characterize their resulting structures and properties, using AlN as example. 14 figures.

  4. Der Global Compact und der Schutz der Menschenrechte

    OpenAIRE

    Hamm, Brigitte I.; Weiß, Norman (Prof. Dr.)

    2001-01-01

    Der Global Compact und der Schutz der Menschenrechte I. Einleitung II. Was ist der Global Compact? III. Wie funktioniert der Global Compact? IV. Der Global Compact will kein Verhaltenskodex sein V. Der Global Compact als Bestandteil von „global governance" VI. Der Global Compact und der Schutz der Menschenrechte VII. Ausschau Literatur „Global Compact" und Schutz der Menschenrechte - Diskussionszusammenfassung

  5. Radiation shielding for future space exploration missions

    Science.gov (United States)

    DeWitt, Joel Michael

    Scope and Method of Study. The risk to space crew health and safety posed by exposure to space radiation is regarded as a significant obstacle to future human space exploration. To countermand this risk, engineers and designers in today's aerospace community will require detailed knowledge of a broad range of possible materials suitable for the construction of future spacecraft or planetary surface habitats that provide adequate protection from a harmful space radiation environment. This knowledge base can be supplied by developing an experimental method that provides quantitative information about a candidate material's space radiation shielding efficacy with the understanding that (1) shielding is currently the only practical countermeasure to mitigate the effects of space radiation on human interplanetary missions, (2) any mass of a spacecraft or planetary surface habitat necessarily alters the incident flux of ionizing radiation on it, and (3) the delivery of mass into LEO and beyond is expensive and therefore may benefit from the possible use of novel multifunctional materials that could in principle reduce cost as well as ionizing radiation exposure. The developed method has an experimental component using CR-39 PNTD and Al2O3:C OSLD that exposes candidate space radiation shielding materials of varying composition and depth to a representative sample of the GCR spectrum that includes 1 GeV 1H and 1 GeV/n 16O, 28Si, and 56Fe heavy ion beams at the BNL NSRL. The computer modeling component of the method used the Monte Carlo radiation transport code FLUKA to account for secondary neutrons that were not easily measured in the laboratory. Findings and Conclusions. This study developed a method that quantifies the efficacy of a candidate space radiation shielding material relative to the standard of polyethylene using a combination of experimental and computer modeling techniques. The study used established radiation dosimetry techniques to present an empirical

  6. A compact 3 T all HTS cryogen-free MRI system

    Science.gov (United States)

    Parkinson, B. J.; Bouloukakis, K.; Slade, R. A.

    2017-12-01

    We have designed and built a passively shielded, cryogen-free 3 T 160 mm bore bismuth strontium calcium copper oxide HTS magnet with shielded gradient coils suitable for use in small animal imaging applications. The magnet is cooled to approximately 16 K using a two-stage cryocooler and is operated at 200 A. The magnet has been passively shimmed so as to achieve ±10 parts per million (ppm) homogeneity over a 60 mm diameter imaging volume. We have demonstrated that B 0 temporal stability is fit-for-purpose despite the magnet operating in the driven mode. The system has produced good quality spin-echo and gradient echo images. This compact HTS-MRI system is emerging as a true alternative to conventional low temperature superconductor based cryogen-free MRI systems, with much more efficient cryogenics since it operates entirely from a single phase alternating current electrical supply.

  7. Compaction and relaxation of biofilms

    KAUST Repository

    Valladares Linares, R.

    2015-06-18

    Operation of membrane systems for water treatment can be seriously hampered by biofouling. A better characterization of biofilms in membrane systems and their impact on membrane performance may help to develop effective biofouling control strategies. The objective of this study was to determine the occurrence, extent and timescale of biofilm compaction and relaxation (decompaction), caused by permeate flux variations. The impact of permeate flux changes on biofilm thickness, structure and stiffness was investigated in situ and non-destructively with optical coherence tomography using membrane fouling monitors operated at a constant crossflow velocity of 0.1 m s−1 with permeate production. The permeate flux was varied sequentially from 20 to 60 and back to 20 L m−2 h−1. The study showed that the average biofilm thickness on the membrane decreased after elevating the permeate flux from 20 to 60 L m−2 h−1 while the biofilm thickness increased again after restoring the original flux of 20 L m−2 h−1, indicating the occurrence of biofilm compaction and relaxation. Within a few seconds after the flux change, the biofilm thickness was changed and stabilized, biofilm compaction occurred faster than the relaxation after restoring the original permeate flux. The initial biofilm parameters were not fully reinstated: the biofilm thickness was reduced by 21%, biofilm stiffness had increased and the hydraulic biofilm resistance was elevated by 16%. Biofilm thickness was related to the hydraulic biofilm resistance. Membrane performance losses are related to the biofilm thickness, density and morphology, which are influenced by (variations in) hydraulic conditions. A (temporarily) permeate flux increase caused biofilm compaction, together with membrane performance losses. The impact of biofilms on membrane performance can be influenced (increased and reduced) by operational parameters. The article shows that a (temporary) pressure increase leads to more

  8. The Shadow of Big Data: Data-Citizenship and Exclusion

    DEFF Research Database (Denmark)

    Rossi, Luca; Hjelholt, Morten; Neumayer, Christina

    2016-01-01

    The shadow of Big Data: data-citizenship and exclusion Big data are understood as being able to provide insights on human behaviour at an individual as well as at an aggregated societal level (Manyka et al. 2011). These insights are expected to be more detailed and precise than anything before...... thanks to the large volume of digital data and to the unobstrusive nature of the data collection (Fishleigh 2014). Within this perspective, these two dimensions (volume and unobstrusiveness) define contemporary big data techniques as a socio-technical offering to society, a live representation of itself....... More precisely, within a system theory approach (Luhmann 1982, 2010), large-scale big data work as a boundary-drawing operation where the difference between the system and its environment is reproduced. Here the result of system observation is defined by what is made visible as (big) data. Within...

  9. AN ANALYSIS OF THE SHADOW ECONOMY IN EU COUNTRIES

    Directory of Open Access Journals (Sweden)

    Brindusa Mihaela Tudose

    2016-08-01

    Full Text Available The paper aims at analysing the dimension of the underground economy in the EU states between 2003 and 2015. In order to achieve this goal, we use qualitative and quantitative methods. In the first two sections of the study we resort to conceptualisation and bring up to date scientific contributions in the field of the shadow economy both in terms of its definition and the methods of quantifying the phenomenon. In the third section, based on the results of the latest research, we identify the dynamics of the underground economy on three levels: the EU-15 (before and after 2005; the EU-10 (before and after the accession of 10 countries in 2005 and the EU-3 (before and after 2007. The main conclusion is that regardless of the reporting level (national, European, world, the real size of the underground economy remains unknown.

  10. Rainforest metropolis casts 1,000-km defaunation shadow.

    Science.gov (United States)

    Tregidgo, Daniel J; Barlow, Jos; Pompeu, Paulo S; de Almeida Rocha, Mayana; Parry, Luke

    2017-08-08

    Tropical rainforest regions are urbanizing rapidly, yet the role of emerging metropolises in driving wildlife overharvesting in forests and inland waters is unknown. We present evidence of a large defaunation shadow around a rainforest metropolis. Using interviews with 392 rural fishers, we show that fishing has severely depleted a large-bodied keystone fish species, tambaqui (Colossoma macropomum), with an impact extending over 1,000 km from the rainforest city of Manaus (population 2.1 million). There was strong evidence of defaunation within this area, including a 50% reduction in body size and catch rate (catch per unit effort). Our findings link these declines to city-based boats that provide rural fishers with reliable access to fish buyers and ice and likely impact rural fisher livelihoods and flooded forest biodiversity. This empirical evidence that urban markets can defaunate deep into rainforest wilderness has implications for other urbanizing socioecological systems.

  11. Structural monitoring of metro infrastructure during shield tunneling construction.

    Science.gov (United States)

    Ran, L; Ye, X W; Ming, G; Dong, X B

    2014-01-01

    Shield tunneling construction of metro infrastructure will continuously disturb the soils. The ground surface will be subjected to uplift or subsidence due to the deep excavation and the extrusion and consolidation of the soils. Implementation of the simultaneous monitoring with the shield tunnel construction will provide an effective reference in controlling the shield driving, while how to design and implement a safe, economic, and effective structural monitoring system for metro infrastructure is of great importance and necessity. This paper presents the general architecture of the shield construction of metro tunnels as well as the procedure of the artificial ground freezing construction of the metro-tunnel cross-passages. The design principles for metro infrastructure monitoring of the shield tunnel intervals in the Hangzhou Metro Line 1 are introduced. The detailed monitoring items and the specified alarming indices for construction monitoring of the shield tunneling are addressed, and the measured settlement variations at different monitoring locations are also presented.

  12. Structural Monitoring of Metro Infrastructure during Shield Tunneling Construction

    Directory of Open Access Journals (Sweden)

    L. Ran

    2014-01-01

    Full Text Available Shield tunneling construction of metro infrastructure will continuously disturb the soils. The ground surface will be subjected to uplift or subsidence due to the deep excavation and the extrusion and consolidation of the soils. Implementation of the simultaneous monitoring with the shield tunnel construction will provide an effective reference in controlling the shield driving, while how to design and implement a safe, economic, and effective structural monitoring system for metro infrastructure is of great importance and necessity. This paper presents the general architecture of the shield construction of metro tunnels as well as the procedure of the artificial ground freezing construction of the metro-tunnel cross-passages. The design principles for metro infrastructure monitoring of the shield tunnel intervals in the Hangzhou Metro Line 1 are introduced. The detailed monitoring items and the specified alarming indices for construction monitoring of the shield tunneling are addressed, and the measured settlement variations at different monitoring locations are also presented.

  13. Electrodynamic Dust Shield for Space Applications

    Science.gov (United States)

    Mackey, Paul J.; Johansen, Michael R.; Olsen, Robert C.; Raines, Matthew G.; Phillips, James R., III; Cox, Rachel E.; Hogue, Michael D.; Calle, Carlos I.; Pollard, Jacob R. S.

    2016-01-01

    The International Space Exploration Coordination Group (ISECG) has chosen dust mitigation technology as a Global Exploration Roadmap (GER) critical technology need in order to reduce life cycle cost and risk, and increase the probability of mission success. NASA has also included Particulate Contamination Prevention and Mitigation as a cross-cutting technology to be developed for contamination prevention, cleaning and protection. This technology has been highlighted due to the detrimental effect of dust on both human and robotic missions. During manned Apollo missions, dust caused issues with both equipment and crew. Contamination of equipment caused many issues including incorrect instrument readings and increased temperatures due to masking of thermal radiators. The astronauts were directly affected by dust that covered space suits, obscured face shields and later propagated to the cabin and into the crew's eyes and lungs. Robotic missions on Mars were affected when solar panels were obscured by dust thereby reducing the effectiveness of the solar panels. The Electrostatics and Surface Physics Lab in Swamp Works at the Kennedy Space Center has been developing an Electrodynamic Dust Shield (EDS) to remove dust from multiple surfaces, including glass shields and thermal radiators. This technology has been tested in lab environments and has evolved over several years. Tests of the technology include reduced gravity flights (6g) in which Apollo Lunar dust samples were successfully removed from glass shields while under vacuum (1 millipascal). Further development of the technology is underway to reduce the size of the EDS as well as to perform material and component testing outside of the International Space Station (ISS) on the Materials on International Space Station Experiment X (MISSE-X). This experiment is designed to verify that the EDS can withstand the harsh environment of space and will look to closely replicate the solar environment experienced on the moon

  14. Cerrobend shielding stents for buccal carcinoma patients

    Directory of Open Access Journals (Sweden)

    Karma Yangchen

    2016-01-01

    Full Text Available Buccal carcinoma is one of the most common oral malignant neoplasms, especially in the South Asian region. Radiotherapy, which plays a significant role in the treatment of this carcinoma, has severe adverse effects. Different types of prosthesis may be constructed to protect healthy tissues from the adverse effects of treatment and concentrate radiation in the region of the tumor mass. However, the technique for fabrication of shielding stent with Lipowitz's alloy (cerrobend/Wood's alloy has not been well documented. This article describes detailed technique for fabrication of such a stent for unilateral buccal carcinoma patients to spare the unaffected oral cavity from potential harmful effects associated with radiotherapy.

  15. Nanoscale microwave microscopy using shielded cantilever probes

    KAUST Repository

    Lai, Keji

    2011-04-21

    Quantitative dielectric and conductivity mapping in the nanoscale is highly desirable for many research disciplines, but difficult to achieve through conventional transport or established microscopy techniques. Taking advantage of the micro-fabrication technology, we have developed cantilever-based near-field microwave probes with shielded structures. Sensitive microwave electronics and finite-element analysis modeling are also utilized for quantitative electrical imaging. The system is fully compatible with atomic force microscope platforms for convenient operation and easy integration of other modes and functions. The microscope is ideal for interdisciplinary research, with demonstrated examples in nano electronics, physics, material science, and biology.

  16. Neutron streaming studies along JET shielding penetrations

    Directory of Open Access Journals (Sweden)

    Stamatelatos Ion E.

    2017-01-01

    Full Text Available Neutronic benchmark experiments are carried out at JET aiming to assess the neutronic codes and data used in ITER analysis. Among other activities, experiments are performed in order to validate neutron streaming simulations along long penetrations in the JET shielding configuration. In this work, neutron streaming calculations along the JET personnel entrance maze are presented. Simulations were performed using the MCNP code for Deuterium-Deuterium and Deuterium- Tritium plasma sources. The results of the simulations were compared against experimental data obtained using thermoluminescence detectors and activation foils.

  17. Optimal Shielding for Minimum Materials Cost of Mass

    Energy Technology Data Exchange (ETDEWEB)

    Woolley, Robert D. [PPPL

    2014-08-01

    Material costs dominate some shielding design problems. This is certainly the case for manned nuclear power space applications for which shielding is essential and the cost of launching by rocket from earth is high. In such situations or in those where shielding volume or mass is constrained, it is important to optimize the design. Although trial and error synthesis methods may succeed a more systematic approach is warranted. Design automation may also potentially reduce engineering costs.

  18. Geometrical aspects of cylindric magnetic shields in strong static fields

    Science.gov (United States)

    Zhiwei, XIA; Wei, LI; Bo, LI; Qingwei, YANG

    2017-11-01

    Motivated by ITER (the International Thermonuclear Experimental Reactor), research on a magnetic shield against a strong field has been carried out. In this paper, a cylindric magnetic shield is studied by using the finite element method with a nonlinear magnetization curve. The geometrical aspects of shielding performance are identified and corresponding suggestions for application are provided. Among them, the effects of the edge and cover thickness have not been mentioned elsewhere to our knowledge.

  19. Topological groups with dense compactly generated subgroups

    Directory of Open Access Journals (Sweden)

    Hiroshi Fujita

    2002-04-01

    Full Text Available A topological group G is: (i compactly generated if it contains a compact subset algebraically generating G, (ii -compact if G is a union of countably many compact subsets, (iii 0-bounded if arbitrary neighborhood U of the identity element of G has countably many translates xU that cover G, and (iv finitely generated modulo open sets if for every non-empty open subset U of G there exists a finite set F such that F  U algebraically generates G. We prove that: (1 a topological group containing a dense compactly generated subgroup is both 0-bounded and finitely generated modulo open sets, (2 an almost metrizable topological group has a dense compactly generated subgroup if and only if it is both 0-bounded and finitely generated modulo open sets, and (3 an almost metrizable topological group is compactly generated if and only if it is -compact and finitely generated modulo open sets.

  20. Properties of Cement Compacts Prepared by High-Pressure Compaction.

    Science.gov (United States)

    1986-05-01

    compressed, low-porosity portland cement pastes. According to work by Relis and Soroka , other factors have been found to produce excellent strength...Pressure Compaction," Journal of the American Concrete Institute, Vol.67, March 1970. 22. Relis, M. and Soroka , I., "Prediction of Standard...No.2, pp.239-245, 1983. 29. Relis, M. and Soroka , I., "Limiting Values for Density, Expansion, and Intrinsic Shrinkage In Hydrated Portland Cement

  1. Shadow Detection Based on Regions of Light Sources for Object Extraction in Nighttime Video

    Directory of Open Access Journals (Sweden)

    Gil-beom Lee

    2017-03-01

    Full Text Available Intelligent video surveillance systems detect pre-configured surveillance events through background modeling, foreground and object extraction, object tracking, and event detection. Shadow regions inside video frames sometimes appear as foreground objects, interfere with ensuing processes, and finally degrade the event detection performance of the systems. Conventional studies have mostly used intensity, color, texture, and geometric information to perform shadow detection in daytime video, but these methods lack the capability of removing shadows in nighttime video. In this paper, a novel shadow detection algorithm for nighttime video is proposed; this algorithm partitions each foreground object based on the object’s vertical histogram and screens out shadow objects by validating their orientations heading toward regions of light sources. From the experimental results, it can be seen that the proposed algorithm shows more than 93.8% shadow removal and 89.9% object extraction rates for nighttime video sequences, and the algorithm outperforms conventional shadow removal algorithms designed for daytime videos.

  2. REMOVING SHADOWS FROM HIGH-RESOLUTION URBAN AERIAL IMAGES BASED ON COLOR CONSTANCY

    Directory of Open Access Journals (Sweden)

    Q. Ye

    2012-08-01

    Full Text Available A method is explored to remove tall building shadows in true color and color infrared urban aerial images based on the theory of color constancy. This paper first uses the specthem ratio and Otsu threshold segmentation methods to detect building shadows on urban aerial true color and color infrared aerial images. Then, based on the shadow detection result, one of the color constancy algorithms SoG (Shades of Gray is used to remove the shadows in aerial images with different p values of the Minkowski norm. Finally, the shadow removal results with different p values have been compared by brightness, contrast and average gradients. The experiments show that the result of this method based on color constancy has a good visual effect, and different from general scene image shadow removal, the aerial images get the best shadow removal result when p is 2. It means the two types of aerial images should not be simply regarded as gray world images.

  3. SHADOW EFFECT ON PHOTOVOLTAIC POTENTIALITY ANALYSIS USING 3D CITY MODELS

    Directory of Open Access Journals (Sweden)

    N. Alam

    2012-07-01

    Full Text Available Due to global warming, green-house effect and various other drawbacks of existing energy sources, renewable energy like Photovoltaic system is being popular for energy production. The result of photovoltaic potentiality analysis depends on data quality and parameters. Shadow rapidly decreases performance of the Photovoltaic system and it always changes due to the movement of the sun. Solar radiation incident on earth's atmosphere is relatively constant but the radiation at earth's surface varies due to absorption, scattering, reflection, change in spectral content, diffuse component, water vapor, clouds and pollution etc. In this research, it is being investigated that how efficiently real-time shadow can be detected for both direct and diffuse radiation considering reflection and other factors in contrast with the existing shadow detection methods using latest technologies and what is the minimum quality of data required for this purpose. Of course, geometric details of the building geometry and surroundings directly affect the calculation of shadows. In principle, 3D city models or point clouds, which contain roof structure, vegetation, thematically differentiated surface and texture, are suitable to simulate exact real-time shadow. This research would develop an automated procedure to measure exact shadow effect from the 3D city models and a long-term simulation model to determine the produced energy from the photovoltaic system. In this paper, a developed method for detecting shadow for direct radiation has been discussed with its result using a 3D city model to perform a solar energy potentiality analysis.

  4. An IMU-Aided Body-Shadowing Error Compensation Method for Indoor Bluetooth Positioning.

    Science.gov (United States)

    Deng, Zhongliang; Fu, Xiao; Wang, Hanhua

    2018-01-20

    Research on indoor positioning technologies has recently become a hotspot because of the huge social and economic potential of indoor location-based services (ILBS). Wireless positioning signals have a considerable attenuation in received signal strength (RSS) when transmitting through human bodies, which would cause significant ranging and positioning errors in RSS-based systems. This paper mainly focuses on the body-shadowing impairment of RSS-based ranging and positioning, and derives a mathematical expression of the relation between the body-shadowing effect and the positioning error. In addition, an inertial measurement unit-aided (IMU-aided) body-shadowing detection strategy is designed, and an error compensation model is established to mitigate the effect of body-shadowing. A Bluetooth positioning algorithm with body-shadowing error compensation (BP-BEC) is then proposed to improve both the positioning accuracy and the robustness in indoor body-shadowing environments. Experiments are conducted in two indoor test beds, and the performance of both the BP-BEC algorithm and the algorithms without body-shadowing error compensation (named no-BEC) is evaluated. The results show that the BP-BEC outperforms the no-BEC by about 60.1% and 73.6% in terms of positioning accuracy and robustness, respectively. Moreover, the execution time of the BP-BEC algorithm is also evaluated, and results show that the convergence speed of the proposed algorithm has an insignificant effect on real-time localization.

  5. Neutron shielding for a {sup 252} Cf source

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H.R.; Manzanares A, E.; Hernandez D, V.M. [Unidades Academicas de Estudios Nucleares e Ingenieria Electrica, Universidad Autonoma de Zacatecas, C. Cipres 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Eduardo Gallego, Alfredo Lorente [Depto. de Ingenieria Nuclear, ETS Ingenieros Industriales, Universidad Politecnica de Madrid, C. Jose Gutierrez Abascal 2, 28006 Madrid (Spain)]. e-mail: fermineutron@yahoo.com

    2006-07-01

    To determine the neutron shielding features of water-extended polyester a Monte Carlo study was carried out. Materials with low atomic number are predominantly used for neutron shielding because these materials effectively attenuate neutrons, mainly through inelastic collisions and absorption reactions. During the selection of materials to design a neutron shield, prompt gamma production as well as radionuclide production induced by neutron activation must be considered. In this investigation the Monte Carlo method was used to evaluate the performance of a water-extended polyester shield designed for the transportation, storage, and use of a {sup 252}Cf isotopic neutron source. During calculations a detailed model for the {sup 252}Cf and the shield was utilized. To compare the shielding features of water extended polyester, the calculations were also made for the bare {sup 252}Cf in vacuum, air and the shield filled with water. For all cases the calculated neutron spectra was utilized to determine the ambient equivalent neutron dose at four sites around the shielding. In the case of water extended polyester and water shielding the calculations were extended to include the prompt gamma rays produced during neutron interactions, with this information the Kerma in air was calculated at the same locations where the ambient equivalent neutron dose was determined. (Author)

  6. Polyolefin-Nanocrystal Composites for Radiation Shielding Project

    Data.gov (United States)

    National Aeronautics and Space Administration — EIC Laboratories Inc. is proposing a lightweight multifunctional polymer/nanoparticle composite for radiation shielding during long-duration lunar missions. Isolated...

  7. Effectiveness of the magnetostatic shielding by the cylindrical shells

    Energy Technology Data Exchange (ETDEWEB)

    Grabchikov, S.S.; Trukhanov, A.V. [SSPA “Scientific and practical materials research centre of NAS of Belarus”, 19 P. Brovki Str., 220072 Minsk (Belarus); Trukhanov, S.V., E-mail: truhanov@ifttp.bas-net.by [SSPA “Scientific and practical materials research centre of NAS of Belarus”, 19 P. Brovki Str., 220072 Minsk (Belarus); Kazakevich, I.S.; Solobay, A.A. [SSPA “Scientific and practical materials research centre of NAS of Belarus”, 19 P. Brovki Str., 220072 Minsk (Belarus); Erofeenko, V.T. [BSU Institution ' Scientific Research Institute of Applied Problems of Mathematics and Informatics ' , av. Nezavisimosti 4 – 702, 220030 Minsk (Belarus); Vasilenkov, N.A. [CJSC ' TESTPRIBOR' , st. Svobody, 31-1, 125362 Moscow (Russian Federation); Volkova, O.S. [Low temperatures physics and superconductivity department, MSU named after M.V. Lomonosov, Moscow (Russian Federation); National University of Science and Technology MISiS, 119049, Moscow, Leninsky Prospekt, 4 (Russian Federation); Shakin, A. [National University of Science and Technology MISiS, 119049, Moscow, Leninsky Prospekt, 4 (Russian Federation)

    2016-01-15

    The experimental research of the magnetostatic shielding effectiveness and the analytical calculations of the average magnetic permeability of single-layer cylindrical sample of the shields based on electrolytically deposited Ni{sub 80}Fe{sub 20} alloy are carried out. The locations of maxima on the Ef(H) and μ(H) curves do not match each other, which is difficult to interpret in terms of the shunting model. The results are explained by the non-linear distribution of the magnetic permeability through the thickness of the shield. It has been shown that in the magnetic fields range from 100 A/m up to 2700 A/m, the shields based on the Ni{sub 80}Fe{sub 20} alloy are preferred over ones based on the 84KHSR amorphous ribbon. It is concluded that at the selection of shield materials it should take into account not only the main magnetic characteristics – μ; H{sub s}; H{sub c} but also H{sub max} parameter, which is important to evaluate the effectiveness of magnetic shielding. - Highlights: • One-layer cylindrical shields based on electrodeposited Ni{sub 80}Fe{sub 20} alloy are obtained. • Magnetostatic shielding effectiveness is experimentally investigated. • Calculations of the average magnetic permeability are carried out. • Results are explained by the non-linear distribution of the magnetic permeability. • Parameters important for the magnetic shielding effectiveness are indicated.

  8. Effect of metal shielding on a wireless power transfer system

    Science.gov (United States)

    Li, Jiacheng; Huang, Xueliang; Chen, Chen; Tan, Linlin; Wang, Wei; Guo, Jinpeng

    2017-05-01

    In this paper, the effect of non-ferromagnetic metal shielding (NFMS) material on the resonator of wireless power transfer (WPT) is studied by modeling, simulation and experimental analysis. And, the effect of NFMS material on the power transfer efficiency (PTE) of WPT systems is investigated by circuit model. Meanwhile, the effect of ferromagnetic metal shielding material on the PTE of WPT systems is analyzed through simulation. A double layer metal shield structure is designed. Experimental results demonstrate that by applying the novel double layer metal shielding method, the system PTE increases significantly while the electromagnetic field of WPT systems declines dramatically.

  9. Electromagnetic shielding effectiveness of 3D printed polymer composites

    Science.gov (United States)

    Viskadourakis, Z.; Vasilopoulos, K. C.; Economou, E. N.; Soukoulis, C. M.; Kenanakis, G.

    2017-12-01

    We report on preliminary results regarding the electromagnetic shielding effectiveness of various 3D printed polymeric composite structures. All studied samples were fabricated using 3D printing technology, following the fused deposition modeling approach, using commercially available filaments as starting materials. The electromagnetic shielding performance of the fabricated 3D samples was investigated in the so called C-band of the electromagnetic spectrum (3.5-7.0 GHz), which is typically used for long-distance radio telecommunications. We provide evidence that 3D printing technology can be effectively utilized to prepare operational shields, making them promising candidates for electromagnetic shielding applications for electronic devices.

  10. Mercuric Iodide Anticoincidence Shield for Gamma-Ray Spectrometer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We utilize a new detector material, polycrystalline mercuric iodide, for background suppression by active anticoincidence shielding in gamma-ray spectrometers. Two...

  11. Mercuric Iodide Anticoincidence Shield for Gamma-Ray Spectrometer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to utilize a new detector material, polycrystalline mercuric iodide, for background suppression by active anticoincidence shielding in gamma-ray...

  12. Graphene shield enhanced photocathodes and methods for making the same

    Science.gov (United States)

    Moody, Nathan Andrew

    2014-09-02

    Disclosed are graphene shield enhanced photocathodes, such as high QE photocathodes. In certain embodiments, a monolayer graphene shield membrane ruggedizes a high quantum efficiency photoemission electron source by protecting a photosensitive film of the photocathode, extending operational lifetime and simplifying its integration in practical electron sources. In certain embodiments of the disclosed graphene shield enhanced photocathodes, the graphene serves as a transparent shield that does not inhibit photon or electron transmission but isolates the photosensitive film of the photocathode from reactive gas species, preventing contamination and yielding longer lifetime.

  13. Photon Shielding Features of Quarry Tuff

    Directory of Open Access Journals (Sweden)

    Vega-Carrillo Hector Rene

    2017-01-01

    Full Text Available Cantera is a quarry tuff widely used in the building industry; in this work the shielding features of cantera were determined. The shielding characteristics were calculated using XCOM and MCNP5 codes for 0.03, 0.07, 0.1, 0.3, 0.662, 1, 2, and 3 MeV photons. With XCOM the mass interaction coefficients, and the total mass attenuation coefficients, were calculated. With the MCNP5 code a transmission experiment was modelled using a point-like source located 42 cm apart from a point-like detector. Between the source and the detector, cantera pieces with different thickness, ranging from 0 to 40 cm were included. The collided and uncollided photon fluence, the Kerma in air and the Ambient dose equivalent were estimated. With the uncollided fluence the linear attenuation coefficients were determined and compared with those calculated with XCOM. The linear attenuation coefficient for 0.662 MeV photons was compared with the coefficient measured with a NaI(Tl-based γ-ray spectrometer and a 137Cs source.

  14. The AA disappearing under concrete shielding

    CERN Multimedia

    CERN PhotoLab

    1982-01-01

    When the AA started up in July 1980, the machine stood freely in its hall, providing visitors with a view through the large window in the AA Control Room. The target area, in which the high-intensity 26 GeV/c proton beam from the PS hit the production target, was heavily shielded, not only towards the outside but also towards the AA-Hall. However, electrons and pions emanating from the target with the same momentum as the antiprotons, but much more numerous, accompanied these through the injection line into the AA ring. The pions decayed with a half-time corresponding to approximately a revolution period (540 ns), whereas the electrons lost energy through synchrotron radiation and ended up on the vacuum chamber wall. Electrons and pions produced the dominant component of the radiation level in the hall and the control room. With operation times far exceeding original expectations, the AA had to be buried under concrete shielding in order to reduce the radiation level by an order of magnitude.

  15. MicroShield/ISOCS gamma modeling comparison.

    Energy Technology Data Exchange (ETDEWEB)

    Sansone, Kenneth R

    2013-08-01

    Quantitative radiological analysis attempts to determine the quantity of activity or concentration of specific radionuclide(s) in a sample. Based upon the certified standards that are used to calibrate gamma spectral detectors, geometric similarities between sample shape and the calibration standards determine if the analysis results developed are qualitative or quantitative. A sample analyzed that does not mimic a calibrated sample geometry must be reported as a non-standard geometry and thus the results are considered qualitative and not quantitative. MicroShieldR or ISOCSR calibration software can be used to model non-standard geometric sample shapes in an effort to obtain a quantitative analytical result. MicroShieldR and Canberras ISOCSR software contain several geometry templates that can provide accurate quantitative modeling for a variety of sample configurations. Included in the software are computational algorithms that are used to develop and calculate energy efficiency values for the modeled sample geometry which can then be used with conventional analysis methodology to calculate the result. The response of the analytical method and the sensitivity of the mechanical and electronic equipment to the radionuclide of interest must be calibrated, or standardized, using a calibrated radiological source that contains a known and certified amount of activity.

  16. A superconducting shield to protect astronauts

    CERN Multimedia

    Antonella Del Rosso

    2015-01-01

    The CERN Superconductors team in the Technology department is involved in the European Space Radiation Superconducting Shield (SR2S) project, which aims to demonstrate the feasibility of using superconducting magnetic shielding technology to protect astronauts from cosmic radiation in the space environment. The material that will be used in the superconductor coils on which the project is working is magnesium diboride (MgB2), the same type of conductor developed in the form of wire for CERN for the LHC High Luminosity Cold Powering project.   Image: K. Anthony/CERN. Back in April 2014, the CERN Superconductors team announced a world-record current in an electrical transmission line using cables made of the MgB2 superconductor. This result proved that the technology could be used in the form of wire and could be a viable solution for both electrical transmission for accelerator technology and long-distance power transportation. Now, the MgB2 superconductor has found another application: it wi...

  17. ITER radiation shielding and neutronics analysis

    Energy Technology Data Exchange (ETDEWEB)

    Santoro, R.T.; Iida, H.; Khripunov, V. [ITER, Garching (Germany). Joint Work Site; Sawan, M. [Fusion Technology Institute, University of Wisconsin, Madison, WI 53706 (United States); Inoue, T. [Japan Atomic Energy Research Institute, Tokai-Mura, Ibaraki-ken (Japan)

    1998-09-01

    Two dimensional radiation transport calculations have been carried out to determine radiation streaming through the ITER equatorial ports. The NBI port has been identified as the most critical. Shielding requirements were estimated to minimize the nuclear heating rates in the toroidal field (TF) coils and the activation of the cryostat, where hands-on maintenance is anticipated. The shielding efficiency of steel/water port walls was investigated as a function of port and wall dimensions and steel volume fraction. For open ports, i.e. the neutral beam injector ducts, 40-50 cm thick port walls composed of 40% SS-60% H{sub 2}O-75% SS-25% H{sub 2}O will reduce the TF coil heating to acceptable levels, while 60-65 cm thick walls are necessary for reducing the dose rates at {proportional_to}2 weeks after shutdown to levels of 750 {mu}Sv h{sup -1} at the cryostat. (orig.) 10 refs.

  18. Concrete enclosure to shield a neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Villagrana M, L. E.; Rivera P, E.; De Leon M, H. A.; Soto B, T. G.; Hernandez D, V. M.; Vega C, H. R., E-mail: emmanuelvillagrana@hotmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Apdo. Postal 336, 98000 Zacatecas (Mexico)

    2012-10-15

    In the aim to design a shielding for a {sup 239}PuBe isotopic neutron source several Monte Carlo calculations were carried out using MCNP5 code. First, a point-like source was modeled in vacuum and the neutron spectrum and the ambient dose equivalent were calculated at several distances ranging from 5 up to 150 cm, these calculations were repeated including air, and a 1 x 1 x 1 m{sup 3} enclosure that was shielded with 5, 15, 20, 25, 30, 50 and 80 cm-thick Portland type concrete walls. At all the points located inside the enclosure neutron spectra from 10{sup -8} up 0.5 MeV were the same regardless the distance from the source showing the room-return effect, for energies larger than 0.5 MeV neutron spectra are diminished as the distance increases. Outside the enclosure it was noticed that neutron spectra becomes -softer- as the concrete thickness increases due to reduction of mean neutron energy. With the ambient dose values the attenuation curve in terms of concrete thickness was calculated. (Author)

  19. Boron filled siloxane polymers for radiation shielding

    Science.gov (United States)

    Labouriau, Andrea; Robison, Tom; Shonrock, Clinton; Simmonds, Steve; Cox, Brad; Pacheco, Adam; Cady, Carl

    2018-03-01

    The purpose of the present work was to evaluate changes to structure-property relationships of 10B filled siloxane-based polymers when exposed to nuclear reactor radiation. Highly filled polysiloxanes were synthesized with the intent of fabricating materials that could shield high neutron fluences. The newly formulated materials consisted of cross-linked poly-diphenyl-methylsiloxane filled with natural boron and carbon nanofibers. This polymer was chosen because of its good thermal and chemical stabilities, as well as resistance to ionizing radiation thanks to the presence of aromatic groups in the siloxane backbone. Highly isotopically enriched 10B filler was used to provide an efficient neutron radiation shield, and carbon nanofibers were added to improve mechanical strength. This novel polymeric material was exposed in the Annular Core Research Reactor (ACRR) at Sandia National Labs to five different neutron/gamma fluxes consisting of very high neutron fluences within very short time periods. Thermocouples placed on the specimens recorded in-situ temperature changes during radiation exposure, which agreed well with those obtained from our MCNP simulations. Changes in the microstructural, thermal, chemical, and mechanical properties were evaluated by SEM, DSC, TGA, FT-IR NMR, solvent swelling, and uniaxial compressive load measurements. Our results demonstrate that these newly formulated materials are well-suitable to be used in applications that require exposure to different types of ionizing conditions that take place simultaneously.

  20. Enhanced radiation shielding with galena concrete

    Directory of Open Access Journals (Sweden)

    Hadad Kamal

    2015-01-01

    Full Text Available A new concrete, containing galena mineral, with enhanced shielding properties for gamma sources is developed. To achieve optimized shielding properties, ten types of galena concrete containing different mixing ratios and a reference normal concrete of 2300 kg/m3 density are studied experimentally and numerically using Monte Carlo and XCOM codes. For building galena concrete, in addition to the main composition, micro-silica and water, galena mineral (containing lead were used. The built samples have high density of 4470 kg/m3 to 5623 kg/m3 and compressive strength of 628 kg/m2 to 685 kg/m2. The half and tenth value layers (half value layer and tenth value layers for the galena concrete, when irradiated with 137Cs gamma source, were found to be 1.45 cm and 4.94 cm, respectively. When irradiated with 60Co gamma source, half value layer was measured to be 2.42 cm. The computation modeling by FLUKA and XCOM shows a good agreement between experimental and computational results.

  1. Gas Shielding Technology for Welding and Brazing

    Science.gov (United States)

    Nunes, Arthur J.; Gradl, Paul R.

    2012-01-01

    Welding is a common method that allows two metallic materials to be joined together with high structural integrity. When joints need to be leak-tight, light-weight, or free of contaminant-trapping seams or surface asperities, welding tends to be specified. There are many welding techniques, each with its own advantages and disadvantages. Some of these techniques include Forge Welding, Gas Tungsten Arc Welding, Friction Stir Welding, and Laser Beam Welding to name a few. Whichever technique is used, the objective is a structural joint that meets the requirements of a particular component or assembly. A key practice in producing quality welds is the use of shielding gas. This article discusses various weld techniques, quality of the welds, and importance of shielding gas in each of those techniques. Metallic bonds, or joints, are produced when metals are put into intimate contact. In the solid-state "blacksmith welding" process, now called Forge Welding (FOW), the site to be joined is pounded into intimate contact. The surfaces to be joined usually need to be heated to make it easier to deform the metal. The surfaces are sprinkled with a flux to melt surface oxides and given a concave shape so that surface contamination can be squeezed out of the joint as the surfaces are pounded together; otherwise the surface contamination would be trapped in the joint and would weaken the weld. In solid-state welding processes surface oxides or other contamination are typically squeezed out of the joint in "flash."

  2. Discussion on variance reduction technique for shielding

    Energy Technology Data Exchange (ETDEWEB)

    Maekawa, Fujio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    As the task of the engineering design activity of the international thermonuclear fusion experimental reactor (ITER), on 316 type stainless steel (SS316) and the compound system of SS316 and water, the shielding experiment using the D-T neutron source of FNS in Japan Atomic Energy Research Institute has been carried out. However, in these analyses, enormous working time and computing time were required for determining the Weight Window parameter. Limitation or complication was felt when the variance reduction by Weight Window method of MCNP code was carried out. For the purpose of avoiding this difficulty, investigation was performed on the effectiveness of the variance reduction by cell importance method. The conditions of calculation in all cases are shown. As the results, the distribution of fractional standard deviation (FSD) related to neutrons and gamma-ray flux in the direction of shield depth is reported. There is the optimal importance change, and when importance was increased at the same rate as that of the attenuation of neutron or gamma-ray flux, the optimal variance reduction can be done. (K.I.)

  3. Photon Shielding Features of Quarry Tuff

    Science.gov (United States)

    Vega-Carrillo, Hector Rene; Hernandez-Adame, Luis; Guzman-Garcia, Karen Arlete; Ortiz-Hernandez, Arturo Agustin; Rodriguez-Rodriguez, Jose Antonio; Juarez-Alvarado, Cesar Antonio

    2017-09-01

    Cantera is a quarry tuff widely used in the building industry; in this work the shielding features of cantera were determined. The shielding characteristics were calculated using XCOM and MCNP5 codes for 0.03, 0.07, 0.1, 0.3, 0.662, 1, 2, and 3 MeV photons. With XCOM the mass interaction coefficients, and the total mass attenuation coefficients, were calculated. With the MCNP5 code a transmission experiment was modelled using a point-like source located 42 cm apart from a point-like detector. Between the source and the detector, cantera pieces with different thickness, ranging from 0 to 40 cm were included. The collided and uncollided photon fluence, the Kerma in air and the Ambient dose equivalent were estimated. With the uncollided fluence the linear attenuation coefficients were determined and compared with those calculated with XCOM. The linear attenuation coefficient for 0.662 MeV photons was compared with the coefficient measured with a NaI(Tl)-based γ-ray spectrometer and a 137Cs source.

  4. Formation and evolution of compact binaries

    NARCIS (Netherlands)

    Sluijs, Marcel Vincent van der

    2006-01-01

    In this thesis we investigate the formation and evolution of compact binaries. Chapters 2 through 4 deal with the formation of luminous, ultra-compact X-ray binaries in globular clusters. We show that the proposed scenario of magnetic capture produces too few ultra-compact X-ray binaries to explain

  5. Compaction Characteristics of Igumale Shale | Iorliam | Global ...

    African Journals Online (AJOL)

    This paper reports the outcome of an investigation into the effect of different compactive energies on the compaction characteristics of Igumale shale, to ascertain its suitability as fill material in highway construction. Tests were conducted on specimen of Igumale shale, which included classification, compaction using three ...

  6. Equationally Compact Acts : Coproducts / Peeter Normak

    Index Scriptorium Estoniae

    Normak, Peeter

    1998-01-01

    In this article equational compactness of acts and its generalizations are discussed. As equational compactness does not carry over to coproducts a slight generalization of c-equational campactness is introduced. It is proved that a coproduct of acts is c-equationally compact if and only if all components are c-equationally campact

  7. Deoxyribonucleic acid-Ag nanoparticles for EMI Shielding: the effect of nanoparticle size, shape and distribution on the shielding effectiveness

    Science.gov (United States)

    Ouchen, Fahima; Wilson, Benjamin G.; Yaney, Perry P.; Salour, Michael M.; Grote, James G.

    2014-09-01

    This study focuses on the use of silver based nanoparticle as fillers in DNA host materials to form nancomposites for applications in Electro-Magnetic Interferences (EMI) shielding. For relatively low-conductivity EMI shielding nanocomposites, silver-oxide coated cenospheres are investigated as fillers. The filler loadings are varied to determine a percolation threshold for the desired low conductivity and shielding effectiveness. Microwave absorption as well as DC surface resistivity measurements are undertaken to characterize the obtained films.

  8. Paddle-based rotating-shield brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yunlong; Xu, Weiyu [Department of Electrical and Computer Engineering, University of Iowa, 4016 Seamans Center, Iowa City, Iowa 52242 (United States); Flynn, Ryan T.; Kim, Yusung; Bhatia, Sudershan K.; Buatti, John M. [Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242 (United States); Dadkhah, Hossein [Department of Biomedical Engineering, University of Iowa, 1402 Seamans Center, Iowa City, Iowa 52242 (United States); Wu, Xiaodong, E-mail: xiaodong-wu@uiowa.edu [Department of Electrical and Computer Engineering, University of Iowa, 4016 Seamans Center, Iowa City, Iowa 52242 and Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242 (United States)

    2015-10-15

    Purpose: The authors present a novel paddle-based rotating-shield brachytherapy (P-RSBT) method, whose radiation-attenuating shields are formed with a multileaf collimator (MLC), consisting of retractable paddles, to achieve intensity modulation in high-dose-rate brachytherapy. Methods: Five cervical cancer patients using an intrauterine tandem applicator were considered to assess the potential benefit of the P-RSBT method. The P-RSBT source used was a 50 kV electronic brachytherapy source (Xoft Axxent™). The paddles can be retracted independently to form multiple emission windows around the source for radiation delivery. The MLC was assumed to be rotatable. P-RSBT treatment plans were generated using the asymmetric dose–volume optimization with smoothness control method [Liu et al., Med. Phys. 41(11), 111709 (11pp.) (2014)] with a delivery time constraint, different paddle sizes, and different rotation strides. The number of treatment fractions (fx) was assumed to be five. As brachytherapy is delivered as a boost for cervical cancer, the dose distribution for each case includes the dose from external beam radiotherapy as well, which is 45 Gy in 25 fx. The high-risk clinical target volume (HR-CTV) doses were escalated until the minimum dose to the hottest 2 cm{sup 3} (D{sub 2cm{sup 3}}) of either the rectum, sigmoid colon, or bladder reached their tolerance doses of 75, 75, and 90 Gy{sub 3}, respectively, expressed as equivalent doses in 2 Gy fractions (EQD2 with α/β = 3 Gy). Results: P-RSBT outperformed the two other RSBT delivery techniques, single-shield RSBT (S-RSBT) and dynamic-shield RSBT (D-RSBT), with a properly selected paddle size. If the paddle size was angled at 60°, the average D{sub 90} increases for the delivery plans by P-RSBT on the five cases, compared to S-RSBT, were 2.2, 8.3, 12.6, 11.9, and 9.1 Gy{sub 10}, respectively, with delivery times of 10, 15, 20, 25, and 30 min/fx. The increases in HR-CTV D{sub 90}, compared to D-RSBT, were 16

  9. Shapes and Positions of Black Hole Shadows in Accretion Disks and Spin Parameters of Black Holes

    OpenAIRE

    Takahashi, Rohta

    2004-01-01

    Can we determine a spin parameter of a black hole by observation of a black hole shadow in an accretion disk? In order to answer this question, we make a qualitative analysis and a quantitative analysis of a shape and a position of a black hole shadow casted by a rotating black hole on an optically thick accretion disk and its dependence on an angular momentum of a black hole. We have found black hole shadows with a quite similar size and a shape for largely different black hole spin paramete...

  10. Cold Nuclear Matter effects on J/psi production at RHIC: comparing shadowing models

    Energy Technology Data Exchange (ETDEWEB)

    Ferreiro, E.G.; /Santiago de Compostela U.; Fleuret, F.; /Ecole Polytechnique; Lansberg, J.P.; /SLAC; Rakotozafindrabe, A.; /SPhN, DAPNIA, Saclay

    2009-06-19

    We present a wide study on the comparison of different shadowing models and their influence on J/{psi} production. We have taken into account the possibility of different partonic processes for the c{bar c}-pair production. We notice that the effect of shadowing corrections on J/{psi} production clearly depends on the partonic process considered. Our results are compared to the available data on dAu collisions at RHIC energies. We try different break up cross section for each of the studied shadowing models.

  11. Use of Shadowing-Based Learning in an Allied Health Microbiology Course

    Directory of Open Access Journals (Sweden)

    Alex A. Lowrey

    2016-05-01

    Full Text Available Students in an undergraduate microbiology course for health professions majors perform a shadowing-based learning exercise for their course project. Students accomplish this by shadowing a health care professional of their choice, specifically incorporating basic microbiological concept themes into their observations. These concept themes include the biological nature, health effects, detection, and control of microorganisms. Upon completion of the shadowing experience, students present a concise report, which is graded on how well the students connect course scientific concepts with actual clinical practice.

  12. Magnetic resonance-guided shielding of prefocal acoustic obstacles in focused ultrasound therapy: application to intercostal ablation in liver.

    Science.gov (United States)

    Salomir, Rares; Petrusca, Lorena; Auboiroux, Vincent; Muller, Arnaud; Vargas, Maria-Isabel; Morel, Denis R; Goget, Thomas; Breguet, Romain; Terraz, Sylvain; Hopple, Jerry; Montet, Xavier; Becker, Christoph D; Viallon, Magalie

    2013-06-01

    reduction of the temperature elevation at the ribs' surface, typically by 3.3 ± 0.4 in vivo. This was translated into an exponential reduction in thermal dose by several orders of magnitude. The external shielding covering the full conical shadow of the ribs was more effective when the protectors could be placed close to the ribs' surface and had a tendency to lose its efficiency when placed further from the ribs. Hepatic parenchyma was safely ablated in vivo using this rib-sparing strategy and single-focus independent sonications. A readily available, MR-compatible, effective, and cost-competitive method for rib protection in transcostal MRgHIFU was validated in this study, using specific reflective strips. The current approach permitted safe intercostal ablation of small volumes (0.7 mL) of liver parenchyma.

  13. Neutron and gamma flux distributions and their implications for radiation damage in the shielded superconducting core of a fusion power plant

    Science.gov (United States)

    Windsor, Colin G.; Morgan, J. Guy

    2017-11-01

    The neutron and gamma ray fluxes within the shielded high-temperature superconducting central columns of proposed spherical tokamak power plants have been studied using the MCNP Monte-Carlo code. The spatial, energy and angular variations of the fluxes over the shield and superconducting core are computed and used to specify experimental studies relevant to radiation damage and activation. The mean neutron and gamma fluxes, averaged over energy and angle, are shown to decay exponentially through the shield and then to remain roughly constant in the core region. The mean energy of neutrons is shown to decay more slowly than the neutron flux through the shield while the gamma energy is almost constant around 2 MeV. The differential neutron and gamma fluxes as a function of energy are examined. The neutron spectrum shows a fusion peak around 1 MeV changing at lower energies into an epithermal E -0.85 variation and at thermal energies to a Maxwellian distribution. The neutron and gamma energy spectra are defined for the outer surface of the superconducting core, relevant to damage studies. The inclusion of tungsten boride in the shield is shown to reduce energy deposition. A series of plasma scenarios with varying plasma major radii between 0.6 and 2.5 m was considered. Neutron and gamma fluxes are shown to decay exponentially with plasma radius, except at low shield thickness. Using the currently known experimental fluence limitations for high temperature superconductors, the continuous running time before the fluence limit is reached has been calculated to be days at 1.4 m major radius increasing to years at 2.2 m. This work helps validate the concept of the spherical tokamak route to fusion power by demonstrating that the neutron shielding required for long lifetime fusion power generation can be accommodated in a compact device.

  14. Probability on compact Lie groups

    CERN Document Server

    Applebaum, David

    2014-01-01

    Probability theory on compact Lie groups deals with the interaction between “chance” and “symmetry,” a beautiful area of mathematics of great interest in its own sake but which is now also finding increasing applications in statistics and engineering (particularly with respect to signal processing). The author gives a comprehensive introduction to some of the principle areas of study, with an emphasis on applicability. The most important topics presented are: the study of measures via the non-commutative Fourier transform, existence and regularity of densities, properties of random walks and convolution semigroups of measures, and the statistical problem of deconvolution. The emphasis on compact (rather than general) Lie groups helps readers to get acquainted with what is widely seen as a difficult field but which is also justified by the wealth of interesting results at this level and the importance of these groups for applications. The book is primarily aimed at researchers working in probability, s...

  15. Compact planar microwave blocking filters

    Science.gov (United States)

    U-Yen, Kongpop (Inventor); Wollack, Edward J. (Inventor)

    2012-01-01

    A compact planar microwave blocking filter includes a dielectric substrate and a plurality of filter unit elements disposed on the substrate. The filter unit elements are interconnected in a symmetrical series cascade with filter unit elements being organized in the series based on physical size. In the filter, a first filter unit element of the plurality of filter unit elements includes a low impedance open-ended line configured to reduce the shunt capacitance of the filter.

  16. Preliminary evaluation of FY98 KALIMER shielding design

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Jae Woon; Kang, Chang Mu; Kim, Young Jin [Korea Atomic Energy Research Institute, Taejon (Korea)

    1999-01-01

    This report describes a preliminary evaluation of the shielding design of FY98 KALIMER. The KALIMER shielding design includes the Inner Fixed Shield of a stainless cylinder located inside the support barrel; the Radial PSDRS Shields which are three B{sub 4}C cylinders located outside the support barrel at core level; the Lower IHX shield of a cylindrical B{sub 4}C plate located above the flow guide; and Inner and Outer IHX shields of B{sub 4}C cylinders located inside and outside of the support barrel, respectively. The DORT3.1 two-dimensional transport code was used to evaluate the KALIMER shielding design. The reactor system was represented by four axial zones, each of which was modeled in the R-Z geometry. The KAFAX-F22 library was used in the analyses, which was generated from the JEF-2.2 of OECD/NEA files for LMR applications by KAERI. The performance of the KALIMER shielding design is compared against the shielding design criteria. The results indicate that the support barrel, upper grid plate, and other reactor structures meet the maximum neutron fluence and DPA limits established in the shielding design criteria. Activities of the air effluent in the PSDRS were also evaluated and are shown to satisfy the maximum permissible concentration (MPC) limits in 10 CFR Part 20. In the future, the validation of the DORT model by a detailed three dimensional calculation such as MCNP and the justification of the current shielding design limits are needed. (author). 13 refs., 23 figs., 31 tabs.

  17. Waiting for Shadows from the Distant Solar System

    Science.gov (United States)

    Kohler, Susanna

    2016-03-01

    How can we hope to measure the hundreds of thousands of objects in our distant solar system? A team of astronomers is harnessing citizen science to begin to tackle this problem!A light curve from an occultation collected by a RECON site in Quincy, California. As the objects shadow passes, the background stars light dims. [RECON/Charley Arrowsmith (Feather River College)]Occultation InformationEstimates currently place the number of Kuiper belt objects larger than 100 km across at over 100,000. Knowing the sizes and characteristics of these objects is important for understanding the composition of the outer solar system and constraining models of the solar systems formation and evolution.Unfortunately, measuring small, dim bodies at large distances is incredibly difficult! One of the best ways to obtain the sizes of these objects is to watch as they occult a distant star. Timing the object as it passes across the face of the star can give us a good measure of its size and shape, when observed from multiple stations in the path of the shadow.An Extended NetworkOccultations by nearby objects (like main-belt asteroids) can be predicted fairly accurately, but those by trans-Neptunian objects are much more poorly constrained. Only ~900 trans-Neptunian objects have approximately known paths, and occultation-shadow predictions for these objects are often only accurate to ~1000km on the Earths surface. So how can we ensure that theres a telescope in the right location, ready to observe when an occultation occurs?Map of the 56 RECON sites distributed over 2000 km in the western United States. [Buie et al. 2016]The simplest answer is to set up a huge network of observing stations, and wait for the shadows to come to the network. With this approach, even if the predicted path isnt precisely known, some of the stations will still observe the occultation.Due to the number of stations needed, this project lends itself perfectly to citizen science. In a recently published paper by

  18. Comminution circuits for compact itabirites

    Directory of Open Access Journals (Sweden)

    Pedro Ferreira Pinto

    Full Text Available Abstract In the beneficiation of compact Itabirites, crushing and grinding account for major operational and capital costs. As such, the study and development of comminution circuits have a fundamental importance for feasibility and optimization of compact Itabirite beneficiation. This work makes a comparison between comminution circuits for compact Itabirites from the Iron Quadrangle. The circuits developed are: a crushing and ball mill circuit (CB, a SAG mill and ball mill circuit (SAB and a single stage SAG mill circuit (SSSAG. For the SAB circuit, the use of pebble crushing is analyzed (SABC. An industrial circuit for 25 million tons of run of mine was developed for each route from tests on a pilot scale (grinding and industrial scale. The energy consumption obtained for grinding in the pilot tests was compared with that reported by Donda and Bond. The SSSAG route had the lowest energy consumption, 11.8kWh/t and the SAB route had the highest energy consumption, 15.8kWh/t. The CB and SABC routes had a similar energy consumption of 14.4 kWh/t and 14.5 kWh/t respectively.

  19. Needle-Bonded Electromagnetic Shielding Thermally Insulating Nonwoven Composite Boards: Property Evaluations

    Directory of Open Access Journals (Sweden)

    Jia-Horng Lin

    2016-10-01

    Full Text Available Complicated environmental problems inevitably arise when technology advances. One major environmental problem is the presence of electromagnetic radiation. Long-term exposure to electromagnetic radiation can damage people’s health in many ways. Therefore, this study proposes producing composite boards with electromagnetic shielding effectiveness and thermal insulation by utilizing the structures and properties of materials. Different combinations of flame-retardant polyester fiber (FR fiber, recycled far-infrared polyester fiber (FI fiber, and 4D low-melting-point fibers (LM fiber were made into flame-retardant and thermally insulating matrices. The matrices and carbon fiber (CF woven fabric in a sandwich-structure were needle-punched in order to be tightly compact, and then circularly heat dried in order to have a heat set and reinforced structure. The test results indicate that Polyester (PET/CF composite boards are mechanically strong and have thermal insulation and electromagnetic shielding effectiveness at a frequency between 0.6 MHz and 3 GHz.

  20. The electromagnetic shielding of Ni films deposited on cenosphere particles by magnetron sputtering method

    Science.gov (United States)

    Yu, Xiaozheng; Shen, Zhigang

    2009-09-01

    Ni-coated cenosphere particles were successfully fabricated by an ultrasonic-assisted magnetron sputtering equipment. Their surface morphology and microstructure were analyzed using field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). FE-SEM results indicate that the Ni films coated by magnetron sputtering are uniform and compact. Ni film uniformity was related with the sputtering power and a large uniform film could be achieved at lower sputtering power. XRD results imply that the Ni film coated on cenospheres was a face-centered cubic (fcc) structure and the crystallization of film sample increases with increasing the sputtering power. The electromagnetic interference (EMI) shielding effectiveness (SE) of Ni-coated cenosphere particles were measured to be 4-27 dB over a frequency range 80-100 GHz, higher than those of uncoated cenosphere particles. The higher sputtering power and Ni film thickness are the higher EMI SE of the specimens. Ni-coated cenosphere particles are most promising alternative candidates for millimeter wave EMI shielding due to their lightweight, low cost, ease of processing, high floating time, good dispersion and tunable conductivities as compared with typical electromagnetic wave countermeasure materials.

  1. The electromagnetic shielding of Ni films deposited on cenosphere particles by magnetron sputtering method

    Energy Technology Data Exchange (ETDEWEB)

    Yu Xiaozheng [Beijing Key Laboratory for Powder Technology R. and D., Beijing University of Aeronautics and Astronautics, Beijing 100083 (China); China National Academy of Nanotechnology and Engineering, Tianjin 300457 (China); Shen Zhigang [Beijing Key Laboratory for Powder Technology R. and D., Beijing University of Aeronautics and Astronautics, Beijing 100083 (China); China National Academy of Nanotechnology and Engineering, Tianjin 300457 (China)], E-mail: shenzhg@buaa.edu.cn

    2009-09-15

    Ni-coated cenosphere particles were successfully fabricated by an ultrasonic-assisted magnetron sputtering equipment. Their surface morphology and microstructure were analyzed using field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). FE-SEM results indicate that the Ni films coated by magnetron sputtering are uniform and compact. Ni film uniformity was related with the sputtering power and a large uniform film could be achieved at lower sputtering power. XRD results imply that the Ni film coated on cenospheres was a face-centered cubic (fcc) structure and the crystallization of film sample increases with increasing the sputtering power. The electromagnetic interference (EMI) shielding effectiveness (SE) of Ni-coated cenosphere particles were measured to be 4-27 dB over a frequency range 80-100 GHz, higher than those of uncoated cenosphere particles. The higher sputtering power and Ni film thickness are the higher EMI SE of the specimens. Ni-coated cenosphere particles are most promising alternative candidates for millimeter wave EMI shielding due to their lightweight, low cost, ease of processing, high floating time, good dispersion and tunable conductivities as compared with typical electromagnetic wave countermeasure materials.

  2. A novel preparation of silver-plated polyacrylonitrile fibers functionalized with antibacterial and electromagnetic shielding properties

    Science.gov (United States)

    Wang, Wei; Li, Weiya; Gao, Cuicui; Tian, Weicheng; Sun, Bin; Yu, Dan

    2015-07-01

    Polyacrylonitrile (PAN) fibers with antibacterial, electromagnetic shielding and antistatic functionalities were fabricated in this paper through modifying PAN fibers with (3-aminopropyl)triethoxysilane (APTES) and 3-mercaptopropyltriethoxysilane (MPTES) sequentially and followed with silver electroless plating. The silver layer on PAN fiber surface was characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD). The results show that the silver layer was plated uniformly and compactly. The surface resistance of plated fabric was about 40 mΩ/sq on average. The antibacterial tests demonstrate that silver-plated PAN fiber exhibits excellent antibacterial property against S. aureus and E. coli with a non-leaching characteristic. The antibacterial property remains good after 30 cycles of standard washing, which is a strong proof of a durable adhesion between metal layer and fiber. The shielding effectiveness (SE) of silver-plated PAN fabric before and after 30 cycles of standard washing was about 40-80 dB and 35-50 dB, respectively. This resultant fiber can be used in many occasions for reducing or preventing electromagnetic interference (EMI) and electromagnetic hazards.

  3. Albedo of Permanently Shadowed Regions of the Lunar Poles

    Science.gov (United States)

    Riner, M. A.; Lucey, P. G.; Bussey, B.; Cahill, J. T.; McGovern, A.

    2012-12-01

    Due to the slight tilt in the Moon's spin axis, some topographic depressions near the lunar poles experience permanent shadow and may serve as cold traps, harboring water ice and/or other volatile compounds [1]. Permanently shadowed regions (PSRs) provide an opportunity toward understanding the amount, nature and transport of volatiles on the Moon and may also be a potential resource for human exploration. While many different data sets have suggested the presence of water ice in PSRs near the lunar poles many questions remain. For example, ice does not appear to be uniformly distributed across identified PSRs. More work is needed to understand the distribution of ice in PSRs and how delivery and retention mechanisms influence the distribution. The active illumination of the Lunar Orbiter Laser Altimeter (LOLA) provides a unique contribution toward exploration PSR exploration. While LOLA is principally a laser altimeter used for quantitative topography and related cartographic and geodetic applications [2], LOLA also measures the intensity and width of the return laser pulse (1064 nm) from the surface. Here we use a global mosaic (4 pixels per degree) of LOLA albedo data corrected for instrumental drift, irregular variations, and calibrated to normal albedo using local equatorial measurements of normal albedo obtained by the Kaguya Multiband Imager [3]. Recent work using LOLA albedo shows the floor of Shackleton crater, near the lunar south pole, is brighter than the surrounding terrain (and the interior of nearby craters) at 1064 nm [4]. This albedo difference may be due to decreased space weathering due to shadowing from the Sun or to a 1 μm thick layer with 20% water ice a the surface of the crater floor [4]. Here we use LOLA dayside reflectance measurements to examine the albedo of PSRs catalogued by [5] derived from illumination modeling of a hybrid 100 m/pixel LOLA-LROC digital terrain model (DTM) up to 83° north and south latitudes. The upper latitude

  4. A COMPACT CONCENTRATION OF LARGE GRAINS IN THE HD 142527 PROTOPLANETARY DUST TRAP

    Energy Technology Data Exchange (ETDEWEB)

    Casassus, Simon; Marino, Sebastian; Pérez, Sebastian; Christiaens, Valentin; Plas, Gerrit van der [Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago (Chile); Wright, Chris M. [School of Physical, Environmental and Mathematical Sciences, UNSW Canberra, P.O. Box 7916, Canberra BC 2610 (Australia); Maddison, Sarah T. [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, P.O. Box 218, Hawthorn, VIC 3122 (Australia); Wootten, Al [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903-2475 (United States); Roman, Pablo; Moral, Victor [Millennium Nucleus “Protoplanetary Disks,” Santiago (Chile); Pinilla, Paola [Leiden Observatory, Leiden University, P.O. Box 9513, 2300RA Leiden (Netherlands); Wyatt, Mark [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Ménard, Francois [UMI-FCA, CNRS/INSU France (UMI 3386), at Departamento de Astronomía, Universidad de Chile, Santiago (Chile); Cieza, Lucas [Facultad de Ingeniería, Universidad Diego Portales, Av. Ejército 441, Santiago (Chile)

    2015-10-20

    A pathway to the formation of planetesimals, and eventually giant planets, may occur in concentrations of dust grains trapped in pressure maxima. Dramatic crescent-shaped dust concentrations have been seen in recent radio images at submillimeter wavelengths. These disk asymmetries could represent the initial phases of planet formation in the dust trap scenario, provided that grain sizes are spatially segregated. A testable prediction of azimuthal dust trapping is that progressively larger grains should be more sharply confined and should follow a distribution that is markedly different from the gas. However, gas tracers such as {sup 12}CO and the infrared emission from small grains are both very optically thick where the submillimeter continuum originates, so previous observations have been unable to test the trapping predictions or to identify compact concentrations of larger grains required for planet formation by core accretion. Here we report multifrequency observations of HD 142527, from 34 to 700 GHz, that reveal a compact concentration of grains approaching centimeter sizes, with a few Earth masses, embedded in a large-scale crescent of smaller, submillimeter-sized particles. The emission peaks at wavelengths shorter than ∼1 mm are optically thick and trace the temperature structure resulting from shadows cast by the inner regions. Given this temperature structure, we infer that the largest dust grains are concentrated in the 34 GHz clump. We conclude that dust trapping is efficient enough for grains observable at centimeter wavelengths to lead to compact concentrations.

  5. Numerical simulation of intelligent compaction technology for construction quality control.

    Science.gov (United States)

    2014-12-01

    Intelligent compaction (IC) technique is a fast-developing technology for compaction quality control and acceptance. Proof rolling using the intelligent compaction rollers after completing compaction can eectively identify : the weak spots and sig...

  6. Active Shielding and Control of Environmental Noise

    Science.gov (United States)

    Tsynkov, S. V.

    2001-01-01

    In the framework of the research project supported by NASA under grant # NAG-1-01064, we have studied the mathematical aspects of the problem of active control of sound, i.e., time-harmonic acoustic disturbances. The foundations of the methodology are described in our paper [1]. Unlike. many other existing techniques, the approach of [1] provides for the exact volumetric cancellation of the unwanted noise on a given predetermined region airspace, while leaving unaltered those components of the total acoustic field that are deemed as friendly. The key finding of the work is that for eliminating the unwanted component of the acoustic field in a given area, one needs to know relatively little; in particular, neither the locations nor structure nor strength of the exterior noise sources need to be known. Likewise, there is no need to know the volumetric properties of the supporting medium across which the acoustic signals propagate, except, maybe, in a narrow area of space near the perimeter of the protected region. The controls are built based solely on the measurements performed on the perimeter of the domain to be shielded; moreover, the controls themselves (i.e., additional sources) are concentrated also only on or near this perimeter. Perhaps as important, the measured quantities can refer to the total acoustic field rather than to its unwanted component only, and the methodology can automatically distinguish between the two. In [1], we have constructed the general solution for controls. The apparatus used for deriving this general solution is closely connected to the concepts of generalized potentials and boundary projections of Calderon's type. For a given total wave field, the application of a Calderon's projection allows one to definitively tell between its incoming and outgoing components with respect to a particular domain of interest, which may have arbitrary shape. Then, the controls are designed so that they suppress the incoming component for the domain

  7. 30 CFR 57.14213 - Ventilation and shielding for welding.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Ventilation and shielding for welding. 57.14213... welding. (a) Welding operations shall be shielded when performed at locations where arc flash could be hazardous to persons. (b) All welding operations shall be well-ventilated. ...

  8. finite element model for predicting residual stresses in shielded

    African Journals Online (AJOL)

    eobe

    *Corresponding author, Tel: +234-803-563-5419. FINITE ELEMENT MODEL FOR PREDICTING RESIDUAL STRESSES IN. SHIELDED MANUAL METAL ARC WELDING OF MILD STEEL PLATES. SHIELDED MANUAL METAL ARC WELDING OF MILD STEEL PLATES. I. U. Musa1,*, M. O. Afolayan. O. Afolayan2 and I. M. ...

  9. Late Proterozoic extensional collapse in the Arabian-Nubian Shield

    NARCIS (Netherlands)

    Blasband, B.B.; White, S.H.; Brooijmans, P.; Boorder, H. de; Visser, W.

    2000-01-01

    A structural and petrological study of the Late Proterozoic rocks in the Wadi Kid area, Sinai, Egypt indicates the presence of an extensional metamorphic core complex in the northern Arabian–Nubian Shield. Gneissic domes throughout the Arabian–Nubian Shield resemble the core complex of the Wadi Kid

  10. Space nuclear reactor shields for manned and unmanned applications

    Science.gov (United States)

    Mckissock, Barbara I.; Bloomfield, Harvey S.

    1990-01-01

    Missions which use nuclear reactor power systems require radiation shielding of payload and/or crew areas to predetermined dose rates. Since shielding can become a significant fraction of the total mass of the system, it is of interest to show the effect of various parameters on shield thickness and mass for manned and unmanned applications. Algorithms were developed to give the thicknesses needed if reactor thermal power, separation distances, and dose rates are given as input. The thickness algorithms were combined with models for four different shield geometries to allow tradeoff studies of shield volume and mass for a variety of manned and unmanned missions. Shield design tradeoffs presented in this study include the effects of: higher allowable dose rates; radiation hardened electronics; shorter crew exposure times; shield geometry; distance of the payload and/or crew from the reactor; and changes in the size of the shielded area. Specific NASA missions that were considered in this study include unmanned outer planetary exploration, manned advanced/evolutionary Space Station, and advanced manned lunar base.

  11. Neoproterozoic tectonics of the Arabian-Nubian Shield

    NARCIS (Netherlands)

    Blasband, B.

    2006-01-01

    The Neoproterozoic tectonic development of the Arabian-Nubian Shield (ANS) can be divided in three parts: 1) the oceanic stage; 2) the arc-accretion stage; 3) the extensional stage. Three key-areas in the Arabian-Nubian Shield, namely the Bi'r Umq Complex, The Tabalah and Tarj Complex and the Wadi

  12. Recent Improvements in the SHIELD-HIT Code

    DEFF Research Database (Denmark)

    Hansen, David Christoffer; Lühr, Armin Christian; Herrmann, Rochus

    2012-01-01

    reproduces experimental measurements with high accuracy. Conclusions: SHIELD-HIT is now faster, more user-friendly and accurate, and has an enhanced functionality with some features being currently unique to SHIELD-HIT. The possibility of data file exchange with existing treatment planning software for heavy...

  13. Sensors measure surface ablation rate of reentry vehicle heat shield

    Science.gov (United States)

    Russel, J. M., III

    1966-01-01

    Sensors measure surface erosion rate of ablating material in reentry vehicle heat shield. Each sensor, which is placed at precise depths in the heat shield is activated when the ablator surface erodes to the location of a sensing point. Sensor depth and activation time determine ablator surface erosion rate.

  14. Thermal radiation shielding by nanoporous membranes based on anodic alumina

    Science.gov (United States)

    Muratova, E. N.; Matyushkin, L. B.; Moshnikov, V. A.; Chernyakova, K. V.; Vrublevsky, I. A.

    2017-07-01

    The paper is devoted to infrared thermography studies of nanoporous alumina membranes with various geometric parameters of the porous layer: its thickness and average pore diameter. Thermal radiation shielding by anodic alumina membranes is presented. The result obtained showed that nanoporous alumina membranes can be used as heat shields to smooth contrast of thermal radiation of the object and the surrounding background.

  15. General Corrosion and Localized Corrosion of the Drip Shield

    Energy Technology Data Exchange (ETDEWEB)

    F. Hua

    2004-09-16

    The repository design includes a drip shield (BSC 2004 [DIRS 168489]) that provides protection for the waste package both as a barrier to seepage water contact and a physical barrier to potential rockfall. The purpose of the process-level models developed in this report is to model dry oxidation, general corrosion, and localized corrosion of the drip shield plate material, which is made of Ti Grade 7. This document is prepared according to ''Technical Work Plan For: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package'' (BSC 2004 [DIRS 171583]). The models developed in this report are used by the waste package degradation analyses for TSPA-LA and serve as a basis to determine the performance of the drip shield. The drip shield may suffer from other forms of failure such as the hydrogen induced cracking (HIC) or stress corrosion cracking (SCC), or both. Stress corrosion cracking of the drip shield material is discussed in ''Stress Corrosion Cracking of the Drip Shield, the Waste Package Outer Barrier, and the Stainless Steel Structural Material'' (BSC 2004 [DIRS 169985]). Hydrogen induced cracking of the drip shield material is discussed in ''Hydrogen Induced Cracking of Drip Shield'' (BSC 2004 [DIRS 169847]).

  16. Impact of Public Education and Regional Economic Growth in China: A Shadow-Price Perspective

    National Research Council Canada - National Science Library

    Zhiqian Yu; Ning Zhu; Tomas Baležentis

    2017-01-01

    .... In order to explore the impacts of education quality on regional economic growth, we employ a quadratic directional distance function to derive the shadow prices of illiteracy for 31 provinces in China...

  17. Leading twist nuclear shadowing, nuclear generalized parton distributions and nuclear DVCS at small x

    Energy Technology Data Exchange (ETDEWEB)

    Guzey, Vadim; Goeke, Klaus; Siddikov, Marat

    2009-01-01

    We generalize the leading twist theory of nuclear shadowing and calculate quark and gluon generalized parton distributions (GPDs) of spinless nuclei. We predict very large nuclear shadowing for nuclear GPDs. In the limit of the purely transverse momentum transfer, our nuclear GPDs become impact parameter dependent nuclear parton distributions (PDFs). Nuclear shadowing induces non-trivial correlations between the impact parameter $b$ and the light-cone fraction $x$. We make predictions for the deeply virtual Compton scattering (DVCS) amplitude and the DVCS cross section on $^{208}$Pb at high energies. We calculate the cross section of the Bethe-Heitler (BH) process and address the issue of the extraction of the DVCS signal from the $e A \\to e \\gamma A$ cross section. We find that the $e A \\to e \\gamma A$ differential cross section is dominated by DVCS at the momentum transfer $t$ near the minima of the nuclear form factor. We also find that nuclear shadowing leads

  18. The Close Objects Buffer : A Sharp Shadow Detection Technique for Radiosity Methods

    NARCIS (Netherlands)

    Telea, A.C.; Overveld, C.W.A.M. van

    1998-01-01

    Detecting sharp illumination variations such as shadow boundaries is an important problem for radiosity methods. Such illumination variations are captured using a nonuniform mesh that refines the areas exhibiting high illumination gradients. Nonuniform meshing techniques like discontinuity meshing

  19. Noise-bound method for detecting shadow-free scene changes in image sequences.

    Science.gov (United States)

    Irie, Kenji; McKinnon, Alan; Unsworth, Keith; Woodhead, Ian

    2010-02-01

    Many image processing applications are confounded by both sensor noise and cast shadows. All image sensors add noise to a captured image that can reduce algorithm sensitivity and performance, and global filters or fixed thresholds are often applied to limit their effects. Cast shadows can appear as scene changes and are difficult to adequately detect and remove from images and image sequences. We couple image-noise statistics with a dual-illumination shadow-detection algorithm to provide a novel color-based method for shadow-free scene-change detection whose performance is bound by metamerism and image noise, and has only one variable--the desired confidence interval for noise separation.

  20. Book review: Confronting the Shadow Education System: What Government Policies for What Private Tutoring'

    Directory of Open Access Journals (Sweden)

    Keith Watson

    2012-10-01

    Full Text Available Book Review Confronting the Shadow Education System: What Government Policies for What Private Tutoring' By Mark Bray (2009, 135pp. ISBN: 078-92-803-1333-8, Paris: IIEP/UNESCO Publishing