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1

WASTE HANDLING BUILDING SHIELD WALL ANALYSIS  

SciTech Connect

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.

D. Padula

2000-01-13

2

Shield Through Rejuvenated Stage Volcanism On Kauai and Niihau, Hawaii  

NASA Astrophysics Data System (ADS)

Kauai and Niihau are the northwesternmost large islands in the Hawaiian chain and consist of shield, rare postshield, and abundant rejuvenated stage lavas. We present new geochronological, geochemical and isotopic data for all phases of volcanic activity on the adjacent islands. K-Ar ages show Niihau shield volcanism occurred from 6.3-4.4 Ma, and K-Ar and new Ar-Ar ages for postshield volcanism range from 5.4-4.7 Ma. Kauai shield volcanism (K-Ar) overlaps with shield volcanism on Niihau. A new Ar-Ar age for a Kauai postshield dike is 4.4 Ma, older than previously-dated postshield lavas (3.95-3.58 Ma). New Ar-Ar ages show that Kauai rejuvenated stage volcanism began prior to 3.42 Ma (Izuka & Sherrod, 2011), compared to ~2.3 Ma on Niihau. Tholeiitic shield lavas from Kauai vary only slightly in trace element chemistry but have variable isotopic compositions. Subtle trends in some trace element and isotopic ratios between Napali Member shield lavas from the east and west side of Kauai support the two-shield hypothesis of Holcomb et al. (1997). Shield lavas from Niihau are chemically similar to those on Kauai, although Niihau tholeiites extend to higher 143Nd/144Nd ratios. Onland and submarine postshield rocks from Niihau are slightly more alkaline and LREE-enriched compared to shield lavas, but postshield rocks from Kauai are more chemically evolved, more LREE-enriched, and have more depleted Sr and Nd isotopic signatures than Kauai tholeiites. Postshield rocks on Kauai overlap in apparent age with lavas that are chemically like later rejuvenated stage lavas, suggesting either interfingering of the chemically distinct lavas or problems with the K-Ar ages. Rejuvenated stage lavas from the two islands differ dramatically; Kauai lavas are alkaline, LREE-enriched, and have even more depleted Sr and Nd isotopic compositions than postshield lavas, whereas Niihau lavas are only mildly alkaline, have lower REE abundances than postshield basalts, but isotopically are like Kauai rejuvenated rocks. Niihau rejuvenated lavas are shifted to slightly higher 87Sr/86Sr at a given 143Nd/144Nd than Kauai rejuvenated lavas, consistent with an enhanced carbonate component in their source (Dixon et al., 2008). Rejuvenated stage lavas have a diagnostic Sr and Nd isotopic signature on both Kauai and Niihau, but on Kauai the isotopic shift begins during the postshield stage. For Kauai, age and geochemical data suggest that volcanic activity was near-continuous from shield to postshield to rejuvenated stage, with a change in mantle source at the postshield to rejuvenated transition. On Niihau, a prominent erosional and age gap separates onland shield and postshield rocks from the rejuvenated stage lavas, with the change in mantle sources at the beginning of the rejuvenated stage. ROV dives on six vents off the NW coast of Niihau recovered a suite of highly alkaline basanites with REE patterns similar to Kauai rejuvenated lavas but with isotopic ratios spanning the range of Niihau shield and postshield lavas. These alkaline lavas are highly vesicular and more altered than rejuvenated stage Niihau rocks, are undated, but may straddle the postshield to rejuvenated stage transition. No equivalents exist at other Hawaiian volcanoes.

Cousens, B.; Clague, D. A.

2013-12-01

3

Methods of investigating construction materials used for intelligent building shielding  

Microsoft Academic Search

Ensuring the appropriate functionality of all the interconnected electric and electronic appliances inside an intelligent building requires an environment where electromagnetic interferences are attenuated so as to eliminate any harmful effects. This paper proposes some straightforward investigation techniques regarding the electromagnetic shielding effectiveness of construction materials. The authors present some simulation methods by developing an original model for shielding capability

M. Romanca; P. Ogrutan; Lia-Elena Aciu; G. Nicolae

2008-01-01

4

Cloud immersion building shielding factors for US residential structures.  

PubMed

This paper presents validated building shielding factors designed for contemporary US housing-stock under an idealized, yet realistic, exposure scenario within a semi-infinite cloud of radioactive material. The building shielding factors are intended for use in emergency planning and level three probabilistic risk assessments for a variety of postulated radiological events in which a realistic assessment is necessary to better understand the potential risks for accident mitigation and emergency response planning. Factors are calculated from detailed computational housing-units models using the general-purpose Monte Carlo N-Particle computational code, MCNP5, and are benchmarked from a series of narrow- and broad-beam measurements analyzing the shielding effectiveness of ten common general-purpose construction materials and ten shielding models representing the primary weather barriers (walls and roofs) of likely US housing-stock. Each model was designed to scale based on common residential construction practices and include, to the extent practical, all structurally significant components important for shielding against ionizing radiation. Calculations were performed for floor-specific locations as well as for computing a weighted-average representative building shielding factor for single- and multi-story detached homes, both with and without basement, as well for single-wide manufactured housing-units. PMID:25340542

Dickson, E D; Hamby, D M

2014-12-01

5

Investigations of some building materials for ?-rays shielding effectiveness  

NASA Astrophysics Data System (ADS)

For construction of residential and non-residential buildings bricks are used as building blocks. Bricks are made from mixtures of sand, clay, cement, fly ash, gypsum, red mud and lime. Shielding effectiveness of five soil samples and two fly ash samples have been investigated using some energy absorption parameters (Mass attenuation coefficients, mass energy absorption coefficients, KERMA (kinetic energy released per unit mass), HVL, equivalent atomic number and electron densities) firstly at 14 different energies from 81-1332 keV then extended to wide energy range 0.015-15 MeV. The soil sample with maximum shielding effectiveness has been used for making eight fly ash bricks [(Lime)0.15 (Gypsum)0.05 (Fly Ash)x (Soil)0.8-x, where values of x are from 0.4-0.7]. High Purity Germanium (HPGe) detector has been used for gamma-ray spectroscopy. The elemental compositions of samples were analysed using an energy dispersive X-ray fluorescence (EDXRF) spectrometer. The agreements of theoretical and experimental values of mass attenuation coefficient have been found to be quite satisfactory. It has been verified that common brick possess the maximum shielding effectiveness for wide energy range 0.015-15 MeV. The results have been shown graphically with some useful conclusions for making radiation safe buildings.

Mann, Kulwinder Singh; Kaur, Baljit; Sidhu, Gurdeep Singh; Kumar, Ajay

2013-06-01

6

North Kona slump: Submarine flank failure during the early(?) tholeiitic shield stage of Hualalai Volcano  

NASA Astrophysics Data System (ADS)

The North Kona slump is an elliptical region, about 20 by 60 km (1000-km 2 area), of multiple, geometrically intricate benches and scarps, mostly at water depths of 2000-4500 m, on the west flank of Hualalai Volcano. Two dives up steep scarps in the slump area were made in September 2001, using the ROV Kaiko of the Japan Marine Science and Technology Center (JAMSTEC), as part of a collaborative Japan-USA project to improve understanding of the submarine flanks of Hawaiian volcanoes. Both dives, at water depths of 2700-4000 m, encountered pillow lavas draping the scarp-and-bench slopes. Intact to only slightly broken pillow lobes and cylinders that are downward elongate dominate on the steepest mid-sections of scarps, while more equant and spherical pillow shapes are common near the tops and bases of scarps and locally protrude through cover of muddy sediment on bench flats. Notably absent are subaerially erupted Hualalai lava flows, interbedded hyaloclastite pillow breccia, and/or coastal sandy sediment that might have accumulated downslope from an active coastline. The general structure of the North Kona flank is interpreted as an intricate assemblage of downdropped lenticular blocks, bounded by steeply dipping normal faults. The undisturbed pillow-lava drape indicates that slumping occurred during shield-stage tholeiitic volcanism. All analyzed samples of the pillow-lava drape are tholeiite, similar to published analyses from the submarine northwest rift zone of Hual?lai. Relatively low sulfur (330-600 ppm) and water (0.18-0.47 wt.%) contents of glass rinds suggest that the eruptive sources were in shallow water, perhaps 500-1000-m depth. In contrast, saturation pressures calculated from carbon dioxide concentrations (100-190 ppm) indicate deeper equilibration, at or near sample sites at water depths of - 3900 to - 2800 m. Either vents close to the sample sites erupted mixtures of undegassed and degassed magmas, or volatiles were resorbed from vesicles during flowage downslope after eruption in shallow water. The glass volatile compositions suggest that the tholeiitic lavas that drape the slump blocks were erupted either (1) early during shield-stage tholeiitic volcanism prior to emergence of a large subaerial edifice, or alternatively (2) from submarine radial vents during subaerial shield-building. Because no radial vents have been documented on land or underwater for the unbuttressed flanks of any Hawaii volcano, alternative (1) is favored. In comparison to other well-documented Hawaiian slumps and landslides, North Kona structures suggest a more incipient slump event, with smaller down-slope motions and lateral displacements.

Lipman, P. W.; Coombs, M. L.

2006-03-01

7

North Kona slump: Submarine flank failure during the early(?) tholeiitic shield stage of Hualalai Volcano  

USGS Publications Warehouse

The North Kona slump is an elliptical region, about 20 by 60 km (1000-km2 area), of multiple, geometrically intricate benches and scarps, mostly at water depths of 2000-4500 m, on the west flank of Hualalai Volcano. Two dives up steep scarps in the slump area were made in September 2001, using the ROV Kaiko of the Japan Marine Science and Technology Center (JAMSTEC), as part of a collaborative Japan-USA project to improve understanding of the submarine flanks of Hawaiian volcanoes. Both dives, at water depths of 2700-4000 m, encountered pillow lavas draping the scarp-and-bench slopes. Intact to only slightly broken pillow lobes and cylinders that are downward elongate dominate on the steepest mid-sections of scarps, while more equant and spherical pillow shapes are common near the tops and bases of scarps and locally protrude through cover of muddy sediment on bench flats. Notably absent are subaerially erupted Hualalai lava flows, interbedded hyaloclastite pillow breccia, and/or coastal sandy sediment that might have accumulated downslope from an active coastline. The general structure of the North Kona flank is interpreted as an intricate assemblage of downdropped lenticular blocks, bounded by steeply dipping normal faults. The undisturbed pillow-lava drape indicates that slumping occurred during shield-stage tholeiitic volcanism. All analyzed samples of the pillow-lava drape are tholeiite, similar to published analyses from the submarine northwest rift zone of Hualalai. Relatively low sulfur (330-600 ppm) and water (0.18-0.47 wt.%) contents of glass rinds suggest that the eruptive sources were in shallow water, perhaps 500-1000-m depth. In contrast, saturation pressures calculated from carbon dioxide concentrations (100-190 ppm) indicate deeper equilibration, at or near sample sites at water depths of -3900 to -2800 m. Either vents close to the sample sites erupted mixtures of undegassed and degassed magmas, or volatiles were resorbed from vesicles during flowage downslope after eruption in shallow water. The glass volatile compositions suggest that the tholeiitic lavas that drape the slump blocks were erupted either (1) early during shield-stage tholeiitic volcanism prior to emergence of a large subaerial edifice, or alternatively (2) from submarine radial vents during subaerial shield-building. Because no radial vents have been documented on land or underwater for the unbuttressed flanks of any Hawaii volcano, alternative (1) is favored. In comparison to other well-documented Hawaiian slumps and landslides, North Kona structures suggest a more incipient slump event, with smaller down-slope motions and lateral displacements.

Lipman, P.W.; Coombs, M.L.

2006-01-01

8

Verification of some building materials as gamma-ray shields.  

PubMed

The shielding properties for gamma rays of a few low Z materials were investigated. The values of the mass attenuation coefficient, equivalent atomic number, effective atomic number, exposure buildup factor and energy absorption buildup factor were calculated and used to estimate the shielding effectiveness of the samples under investigation. It has been observed that the shielding effectiveness of a sample is directly related to its effective atomic number. The shielding character of any sample is a function of the incident photon energy. Good shielding behaviour has been verified in soil samples in the photon energy region of 0.015-0.30 MeV and of dolomite in 3-15 MeV. The results have been shown graphically with more useful conclusions. PMID:22223719

Mann, Kulwinder Singh; Singla, Jyoti; Kumar, Vipan; Sidhu, G S

2012-08-01

9

Shielding and Build-up Considerations for Radiation Detection  

SciTech Connect

Abstract -- Shielding for gamma radiation has traditionally focused on the reduction of dose effects. For these applications, reducing the energy of the radiation is important along with reducing the actual number of photons, and therefore large masses of high Z material are typically used. However, for measurements requiring low backgrounds or for detecting low activity signals, such as in homeland security applications, the primary use of shielding is to decrease the total number of background photons (perhaps in a region of interest), and therefore the processes of buildup and down scattering become important. In these applications, where the important measure is count rate instead of dose and low background are important, improved reduction in counts from background radiation may be achieved with specially designed configurations of thin layers of different materials instead of a single thick layer. This paper briefly describes recent modeling and experimental investigations in layered-shielding methodology and provides results with comparison to single shielding material such as Pb. Application of these techniques to some real world problems, such as detector systems for homeland security, is discussed.

Ely, James H.; Kernan, Warnick J.; Kouzes, Richard T.; Siciliano, Edward R.

2008-10-19

10

SPERTI Reactor Pit Building (PER605). Earth shielding protect adjacent Instrument ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

SPERT-I Reactor Pit Building (PER-605). Earth shielding protect adjacent Instrument Cell (PER-606). Security fencing surrounds complex, to which gate entry is provided next to Guard House (PER-607). Note gravel road leading to control area. Earth-covered conduit leads from instrument cell to terminal building out of view. Photographer: R.G. Larsen. Date: June 22, 1955. INEEL negative no. 55-1701 - Idaho National Engineering Laboratory, SPERT-I & Power Burst Facility Area, Scoville, Butte County, ID

11

PLUG STORAGE BUILDING, TRA611, AS IT LOOKED WITH EARTHEN SHIELD ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

PLUG STORAGE BUILDING, TRA-611, AS IT LOOKED WITH EARTHEN SHIELD COVERING STORAGE TUBES. MTR WING, TRA-604, AT RIGHT OF VIEW. CAMERA FACES NORTHWEST. INL NEGATIVE NO. 3177. Unknown Photographer, 8/29/1951 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

12

LPT. Shield test control building (TAN645), north facade. Camera facing ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

LPT. Shield test control building (TAN-645), north facade. Camera facing south. Obsolete sign dating from post-1970 program says "Energy and Systems Technology Experimental Facility, INEL." INEEL negative no. HD-40-5-4 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID

13

HOT CELL BUILDING, TRA632. HOT CELL AWAITS INSTALLATION OF SHIELDED ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

HOT CELL BUILDING, TRA-632. HOT CELL AWAITS INSTALLATION OF SHIELDED WINDOWS. OVERHEAD MASTER/SLAVE MANIPULATORS (LEFT, ABOVE WORKING WINDOWS) WILL MOVE ACROSS GUIDE RAILS IN SLOT ABOVE THE WINDOWS. CAMERA FACING SOUTHEAST. INL NEGATIVE NO. 8996. Unknown Photographer, 10/28/1953 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

14

HOT CELL BUILDING, TRA632. SHIELDED WINDOWS HAVE BEEN INSTALLED. MANIPULATORS ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

HOT CELL BUILDING, TRA-632. SHIELDED WINDOWS HAVE BEEN INSTALLED. MANIPULATORS AWAIT ATTACHMENT TO HAND CONTROLS. INL NEGATIVE NO. 9001. Unknown Photographer, photo is identified as taken 10/28/1953, but it may be an error as it shows progress since ID-33-G-266 of same date. - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

15

Three-dimensional analysis of AP600 standard plant shield building roof  

SciTech Connect

The AP600 passive containment vessel is surrounded by a concrete cylindrical shell covered with a truncated conical roof. This roof supports the passive containment cooling system (PCS) annular tank, shield plate and other nonstructural attachments. When the shield building is subjected to different loading combinations as defined in the Standard Review Plan (SRP), some of the sections in the shield building could experience forces in excess of their design values. This report summarized the three-dimensional finite element analysis that was conducted to review the adequacy of the proposed Westinghouse shield building design. The ANSYS finite element software was utilized to analyze the Shield Building Roof (SBR) under dead, snow, wind, thermal and seismic loadings. A three-dimensional model that included a portion of the shield building cylindrical shell, the conical roof and its attachments, the eccentricities at the cone-cylinder connection and at the compression ring and the PCS tank was developed. Mesh sensitivity studies were conducted to select appropriate element size in the cylinder, cone, near air intakes and in the vicinity of the eccentricities. Also, a study was carried out to correctly idealize the water-structure interaction in the PCS tank. Response spectrum analysis was used to calculate the internal forces at different sections in the SBR under Safe Shutdown Earthquake (SSE). Forty-nine structural modes and twenty sloshing modes were used. Two horizontal components of the SSE together with a vertical component were used. Modal stress resultants were combined taking into account the effects of closely spaced modes. The three earthquake directions were combined by the Square Root of the Sum Squares method. Two load combinations were studied. The load combination that included dead, snow, fluid, thermal and seismic loads was selected to be the most critical. Interaction diagrams for critical sections were developed and used to check the design adequacy. The results demonstrated that provided area of steal on each face of several sections of the AP600 SBR was inadequate. This was also noticed when comparing the total provided area of steel per section, i.e., the area of steel on both faces. The discrepancy between Westinghouse results and these reported herein could have resulted from the different finite element mesh sizes and the assumption used in Westinghouse design.

Greimann, L.; Fanous, F.; Safar, S.; Khalil, A.; Bluhm, D.

1999-06-01

16

LPT. Shield test facility assembly and test building (TAN646). East ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

LPT. Shield test facility assembly and test building (TAN-646). East facade of ebor helium wing addition. Camera facing west. Note asbestos-cement siding on stair enclosure and upper-level. Concrete siding at lower level. Metal stack. Monorail protrudes from upper level of south wall at left of view. INEEL negative no. HD-40-7-4 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID

17

Linear attenuation coefficient and build up factor of MCP-96 alloy for radiation shielding and protection  

Microsoft Academic Search

Build-up factors and linear attenuation coefficients of MCP-96 alloy are determined for radiation shielding and protection, using ^60Co and ^137Cs gamma emitters. A narrow collimated beam of gamma-rays is passed through various thicknesses of MCP-96 alloy and the attenuation in the intensity of the beam is determined. The thickness of the 4 x 4 cm^2 blocks varies from 0.5 cm

Deidre Hopkins; Muhammad Maqbool; Mohammed Islam

2009-01-01

18

Isotopic geochemistry of Hualalai shield-stage tholeiitic basalts from submarine North Kona region, Hawaii  

NASA Astrophysics Data System (ADS)

The geochemical data of Hualalai tholeiitic basalts allow extension of the temporal variations established at Mauna Loa back in time, and provide important information for the long-term temporal variation of the Hawaiian lavas. We report new Hf, Pb, Nd, and Sr isotope compositions for 32 Hualalai tholeiitic basalts collected from deep submarine portions of the North Kona region. The samples were collected from the lower section of the North Kona bench (dives K218 and K219), a submarine stratigraphic section at Hualalai volcano's northwest rift zone (dive S690), and an elongate ridge outboard of the central section of the bench (dive S692), during two JAMSTEC Hawaii cruises in 2001 and 2002. The Hualalai shield-stage tholeiitic basalts have magma source isotopic signatures similar to Mauna Loa. The new data shows temporal Pb and Sr isotope trends that correspond to the long-term temporal variations in Loa-trend lavas, and the Hualalai-Mauna Loa lavas seem to show inter-shield geochemical excursions. Variation in Pb and Sr isotopes at Hualalai appears to take place over a longer time scale than at Mauna Loa. The merged Hualalai-Mauna Loa isotopic trends support models where heterogeneous material in the plume conduit is distributed chaotically, with variable cross-sectional density and length scale.

Yamasaki, Seiko; Kani, Tomomi; Hanan, Barry B.; Tagami, Takahiro

2009-09-01

19

Linear attenuation coefficient and build up factor of MCP-96 alloy for radiation shielding and protection  

NASA Astrophysics Data System (ADS)

Build-up factors and linear attenuation coefficients of MCP-96 alloy are determined for radiation shielding and protection, using ^60Co and ^137Cs gamma emitters. A narrow collimated beam of ?-rays is passed through various thicknesses of MCP-96 alloy and the attenuation in the intensity of the beam is determined. The thickness of the 4 x 4 cm^2 blocks varies from 0.5 cm to 6 cm. Plotting the thickness of the alloy and the corresponding intensity of the beam allowed us to determine its linear attenuation coefficient. The narrow beam geometry is then replaced by broad beam geometry by removing the collimator and the radiation beam is able to interact with the MCP-96 alloy at all possible positions facing the radiation source. Additional radiations obtained by the detector as a result from the scattering of radiation develops the build-up factor. The buildup factor is then calculated using the attenuated beam received by the detector in the broad beam geometry and in the narrow beam geometry. The buildup factor is found to be dependent on the thickness of the MCP-96 attenuator, the beam energy and the source to attenuator distance. These values are providing ways for dose correction in radiation oncology and radiation shielding and protection when MCP-96 is used as tissue compensator or for radiation protection purposes.

Hopkins, Deidre; Maqbool, Muhammad; Islam, Mohammed

2009-10-01

20

An iterative method for calculating gamma-ray build-up factors in multi-layer shields.  

PubMed

Point kernel codes that simulate gamma-ray transport often use build-up factors to take scattered photons into account. This study introduces a new method, for computing multi-layer shield build-up factors. This method, based on an empirical formula for calculating double-layer shield build-up factors, is iterative. For an N-layer shield, each iteration of the method treats the first and the second layer of the shield. It replaces these layers by a single equivalent layer composed of an appropriate material and, hence, it turns the N-layer shield into an (N - 1)-layer shield. In order to determine the equivalent layer of an appropriate material, a neural network approach is developed: some neural networks trained on a large set of various configurations provide the equivalent material for any double-layer configuration. The method is implemented into MERCURE-6.3 straight-line attenuation code and is validated by comparison between MERCURE-6.3 results and reference data for one-dimensional geometries. Reference data obtained from transport calculations performed using the Sn transport code TWODANT. The comparisons prove the accuracy and sturdiness of the method. PMID:16604684

Suteau, C; Chiron, M

2005-01-01

21

Pb, Hf, Nd, and Sr Isotopic Variations of Hualalai Shield Stage Tholeiites from the Submarine North Kona Region  

NASA Astrophysics Data System (ADS)

We present the isotope and trace element compositions of tholeiitic lavas collected from deep submarine portions of North Kona region, the west flank of Hualalai volcano. The samples were collected from the lower section of the North Kona bench (dives K218 and K219), a submarine section at Hualalai volcano's northwest rift zone (dive S690), and an elongate ridge below the central section of the bench (dive S692) during 2001 and 2002 JAMSTEC Hawaii cruises. Hualalai volcano is presently in the post-shield alkalic stage and most of its subaerial surface is covered by alkalic basalt. All analyzed samples of the pillow lavas are tholeiites that erupted during Hualalai shield stage. It is important to identify source materials involved in the volumetrically dominant stage of Hualalai volcano in order to provide constraints for the size and distribution of compositional heterogeneities of Hawaiian plume. The isotopic compositions of the submarine North Kona tholeiites are similar to the data previously reported for Mauna Loa tholeiites. The data trends define clear mixing relationships that require at least three mantle source components. The mixing is dominated by a Koolau-like enriched component and a Kea-like depleted component. The K219 data trend toward higher epsilon Hf and 87Sr/86Sr relative to the K218, S690, and S692 arrays, requiring another component similar to that observed in post-shield lavas of Hualalai volcano. Pb isotopic compositions for samples from dive K218 and K219 form distinct non-overlapping Pb-Pb arrays suggesting further source heterogeneity. Samples from dive S690 and S692 plot on both of these trends. These findings suggest small-scale compositional heterogeneity in the source regions that can be attributed to anomalous irregular 'blobs' involved in late shield stage magmatism of Mauna Loa reported in previous works.

Yamasaki, S.; Kani, T.; Hanan, B. B.; Tagami, T.

2007-12-01

22

The TRADE experiment: shielding calculations for the building hosting the subcritical system.  

PubMed

The TRADE project (TRiga Accelerator Driven Experiment), to be performed at the existing TRIGA reactor at ENEA Casaccia, has been proposed as a validation of the accelerator-driven system (ADS) concept. TRADE will be the first experiment in which the three main components of an ADS--the accelerator, spallation target and sub-critical blanket--are coupled at a power level sufficient to encounter reactivity feedback effects. As such, TRADE represents the necessary intermediate step in the development of hybrid transmutation systems, its expected outcomes being considered crucial--in terms of proof of stability of operation, dynamic behaviour and licensing issues--for the subsequent realisation of an ADS Transmutation Demonstrator. An essential role in the feasibility study of the experiment is played by radioprotection calculations. Such a system exhibits new characteristics with respect to a traditional reactor, owing to the presence of the proton accelerator. As beam losses always occur under normal operating conditions of an accelerator, shielding studies need to be performed not only around the reactor but also along the beam line from the accelerator to the spallation target. This paper illustrates a preliminary evaluation, using Monte Carlo methods, of the additional shielding to be located around the reactor structures, the beam transport line and the existing reactor building to allow access into the reactor hall and to restrict the doses outside to their legal limits. PMID:16381710

Burn, K W; Carta, M; Casalini, L; Kadi, Y; Monti, S; Nava, E; Palomba, M; Petrovich, C; Picardi, L; Rubbia, C; Troiani, F

2005-01-01

23

Building A New Kind of Graded-Z Shield for Swift's Burst Alert Telescope  

NASA Technical Reports Server (NTRS)

The Burst Alert Telescope (BAT) on Swift has a graded-Z Shield that closes out the volume between the coded aperture mask and the Cadmium-Zinc-Telluride (CZT) detector array. The purpose of the 37 kilogram shield is to attenuate gamma rays that have not penetrated the coded aperture mask of the BAT instrument and are therefore a major source of noise on the detector array. Unlike previous shields made from plates and panels, this shield consists of multiple layers of thin metal foils (lead, tantalum, tin, and copper) that are stitched together much like standard multi-layer insulation blankets. The shield sections are fastened around BAT, forming a curtain around the instrument aperture. Strength tests were performed to validate and improve the design, and the shield will be vibration tested along with BAT in late 2002. Practical aspects such as the layup design, methods of manufacture, and testing of this new kind of graded-Z Shield are presented.

Robinson, David W.

2002-01-01

24

METHODS OF MAKING CONCRETE BLOCKS FOR THE SHIELDING WALLS OF BUILDINGS HOUSING NUCLEAR REACTORS AND ACCELERATORS  

Microsoft Academic Search

A reactor shielding wall was made of precast concrete blocks, measuring ; 1.855 x 1.785 x 1.850 m and weighing 13.6 tons, which were placed on a heavy ; solution mortar, forming a 1-cm-thick seam. The seam density checked with a ; gamma installation was satisfactory. For experimental purposes type 100 concrete ; was used for making 2 x 1

Zaytsev

1962-01-01

25

Improvements to building energy usage modeling during early design stages and retrofits  

E-print Network

A variety of improvements to the MIT Design Advisor, a whole-building energy usage modeling tool intended for use during early design stages, are investigated. These include changes to the thermal mass temperature distribution ...

Mandelbaum, Andrew (Andrew Joseph)

2014-01-01

26

The Initial Stage of a School's Capacity Building  

ERIC Educational Resources Information Center

The rationale of this article is that schools and their leaders need to establish and formalize a system which focuses on integrating staff effectively into the organization's community and instituting esteem and competency. Competent educators in a professional community constitute two of the three dimensions that build the capacity to create…

Stocklin, Sacha

2010-01-01

27

Characterization of organic air emissions from the Certification and Segregation Building and Air Support Weather Shield II at the Radioactive Waste Management Complex  

Microsoft Academic Search

During the latter part of Fiscal Year (FY-92), a task was initiated to characterize the organic air emissions from the Certification and Segregation (C and S) Building [Waste Management Facility (WMF) 612] and the Air Support Weather Shield II (ASWS II or ASB II) (WMF 711) at the Radioactive Waste Management Complex (RWMC). The purpose of this task, titled the

D. S. Shoop; J. M. Jackson; J. G. Jolley; K. J. Izbicki

1994-01-01

28

Full-building radiation shielding for climate control in desert regions  

Microsoft Academic Search

The efficacy of full-building radiation barriers for use in climate control has been analyzed both analytically and experimentally. The mutually reinforcing results suggest that heat transfer through corrugated metal roofs can be dramatically reduced through the use of inexpensive, highly reflective sheets. The experiments were performed on two types of structures, one with a single metal roof and the other

John Abraham; Camille George

2007-01-01

29

Final environmental assessment: TRU waste drum staging building, Technical Area 55, Los Alamos National Laboratory  

SciTech Connect

Much of the US Department of Energy`s (DOE`s) research on plutonium metallurgy and plutonium processing is performed at Los Alamos National Laboratory (LANL), in Los Alamos, New Mexico. LANL`s main facility for plutonium research is the Plutonium Facility, also referred to as Technical Area 55 (TA-55). The main laboratory building for plutonium work within the Plutonium Facility (TA-55) is the Plutonium Facility Building 4, or PF-4. This Environmental Assessment (EA) analyzes the potential environmental effects that would be expected to occur if DOE were to stage sealed containers of transuranic (TRU) and TRU mixed waste in a support building at the Plutonium Facility (TA-55) that is adjacent to PF-4. At present, the waste containers are staged in the basement of PF-4. The proposed project is to convert an existing support structure (Building 185), a prefabricated metal building on a concrete foundation, and operate it as a temporary staging facility for sealed containers of solid TRU and TRU mixed waste. The TRU and TRU mixed wastes would be contained in sealed 55-gallon drums and standard waste boxes as they await approval to be transported to TA-54. The containers would then be transported to a longer term TRU waste storage area at TA-54. The TRU wastes are generated from plutonium operations carried out in PF-4. The drum staging building would also be used to store and prepare for use new, empty TRU waste containers.

NONE

1996-02-09

30

Lithospheric Expressions of the Precambrian Shield, Mesozoic Rifting, and Cenozoic Subduction and Mountain Building in Venezuela  

NASA Astrophysics Data System (ADS)

The Caribbean (CAR)-South American (SA) plate boundary in Venezuela is a broad zone of faulting and diffuse deformation. GPS measurements show the CAR moving approximately 2 cm/yr relative to SA, parallel to the strike slip fault system in the east, with more oblique convergence in the west (Weber et al., 2001) causing the southern edge of the Caribbean to subduct beneath northwestern South America. The west is further complicated by the motion of the triangular Maracaibo block, which is escaping northeastward relative to SA along the Bocono and Santa Marta Faults. In central and eastern Venezuela, plate motion is accommodated by transpression and transtension along the right lateral San Sebastian- El Pilar strike-slip fault system. The strike-slip system marks the northern edge of coastal thrust belts and their associated foreland basins. The Archean-Proterozoic Guayana Shield, part of the Amazonian Craton, underlies southeastern and south-central Venezuela. We used the 87 station Venezuela-U.S. BOLIVAR array (Levander et al., 2006) to investigate lithospheric structure in northern South America. We combined finite-frequency Rayleigh wave tomography with Ps and Sp receiver functions to determine lithosphere-asthenosphere boundary (LAB) depth. We measured Rayleigh phase velocities from 45 earthquakes in the period band 20-100s. The phase velocities were inverted for 1D shear velocity structure on a 0.5 by 0.5 degree grid. Crustal thickness for the starting model was determined from active seismic experiments and receiver function analysis. The resulting 3D shear velocity model was then used to determine the depth of the LAB, and to CCP stack Ps and Sp receiver functions from ~45 earthquakes. The receiver functions were calculated in several frequency bands using iterative deconvolution and inverse filtering. Lithospheric thickness varies by more a factor of 2.5 across Venezuela. We can divide the lithosphere into several distinct provinces, with LAB depth reflecting the signatures of the Precambrian craton in the south, Mesozoic rifting in central Venezuela, and Neogene subduction and orogenesis in both the northeast and northwest. Specifically, LAB depth varies from 110-130 km beneath the Guayana Shield, in agreement with finite-frequency body wave tomography (Bezada et al., 2010b). To the north beneath the Serrania del Interior and Maturin Basin the Rayleigh waves image two high velocity features to depths of 200 km. The northernmost, beneath the Serrania, corresponds to the top of the subducting Atlantic plate, in agreement with P-wave tomography that images the Atlantic plate to transition zone depths. Another localized high velocity feature extending to ~200 km depth lies to the south. We speculate that this is a lithospheric drip caused by destabilization of the SA lithospheric caused by Atlantic subduction. Immediately to the west beneath the Cariaco basin the LAB is at ~50 km, marking the top of a pronounced low velocity zone. The thin lithosphere extends southwestward from the Cariaco Basin beneath the Mesozoic Espino Graben to the craton. To the west the LAB deepens to ~80 km beneath the Barinas Apure Basin and then to ~90 km beneath the Neogene Merida Andes and Maracaibo block.

Levander, A.; Masy, J.; Niu, F.

2013-05-01

31

EXPERIMENTAL VERIFICATION OF SHIELDING EQUATIONS  

Microsoft Academic Search

S>Building factors for iron shields, lead shields, and laminated iron-; lead shields (1.7 mean free paths of lead and 1 to 3 mean free paths of iron per ; lamination) were determined for shield thicknesses up to 6.8 mean free paths of ; lead, 8.7 mean free paths of iron, and 9.2 mean free paths of laminated shielding. ; A

C. L. Kusik; T. R. Jaworowski; D. C. Morse; D. G. Strawson

1957-01-01

32

Creating Socionas: Building creative understanding of people's experiences in the early stages of new product development  

Microsoft Academic Search

This work presents the research into Creating Socionas, a step-by-step approach to building creative understanding of user experience in the early stages of new product development (NPD). Creative understanding is the combination of a rich, cognitive and affective understanding of the other, and the ability to translate this understanding into products and services that are pleasurable and easy to use

C. E. Postma

2012-01-01

33

Structural response of nuclear containment shield buildings with unanticipated construction openings  

NASA Astrophysics Data System (ADS)

As Nuclear Power Plants age many require steam generator replacement. There is a nickel alloy in the steam generator tubes that is susceptible to stress cracking and although these cracks can be sealed the generator becomes uneconomical without 10%-15% of the tubes. The steam generator in a typical nuclear power plant is housed in the containment structure next to the reactor. The equipment hatch is not big enough to facilitate steam generator replacement, thus construction openings in the dome of the containment structure are required. To date the structural consequences of construction openings in the dome have not been examined. This thesis examines the effects of such openings. The prototype concrete dome is made up of a 2 ft thick dome atop 3 ft thick and 170 ft high cylindrical walls (radius 65.5 ft) with a tension ring 15 ft high and 8 ft thick in between. The dome of the building is cast in two layers; a lower 9 inch layer that serves as the formwork for an upper 15 inch layer. The weight of the dome is carried in axial compression along the hoops and meridians of the dome. The first finite element model uses shell elements and considers two limiting load cases; where the two layers act as one, and where the lower layer carries the weight of both. The openings interrupt the hoops and meridians and the weight of the dome must be redistributed around the openings. Without openings, the stresses due to dead load in the structure are very low when compared to the material strength. The impact of the openings is increased compression stresses near the opening. The maximum stresses are approximately four times larger than in the original structure. These results are confirmed by the second model which is made from layers of solid elements. This model shows a significant difference between the compression on the top surface of the dome, in the affected areas, and that on the bottom surface, leading to shear stresses. These shear stresses are largest around the opening but are not large enough to cause delamination.

Mac Namara, Sinead Caitriona

34

ON THE DETERMINATION OF GAMMA-RAY ATTENUATION FACTORS OF SHIELDING MATERIALS BY MEANS OF DIFFERENTIAL BUILD-UP-MEASURING  

Microsoft Academic Search

A method for measuring gamma-ray attenuation factors of shielding ; materials is described in which only small samples of material are needed. This ; method makes use of a narrow beam. The scattered radiation is measured by means ; of a scintiliation crystal in dependence of the distance aside from the primary ; beam immediately behind the shield. The first

W. Futtermenger; H. Glubrecht; E. G. Niemann; H. Schultz

1962-01-01

35

On the developmenet of multi-linear regression analysis to assess energy consumption in the early stages of building design  

NASA Astrophysics Data System (ADS)

Modeling of energy consumption in buildings is essential for different applications such as building energy management and establishing baselines. This makes building energy consumption estimation as a key tool to achieve the goals on energy consumption and emissions reduction. Energy performance of building is complex, since it depends on several parameters related to the building characteristics, equipment and systems, weather, occupants, and sociological influences. This paper presents a new model to predict and quantify energy consumption in commercial buildings in the early stages of the design. eQUEST and DOE-2 building simulation software was used to build and simulate individual building configuration that were generated using Monte Carlo simulation technique. Ten thousands simulations for seven building shapes were performed to create a comprehensive dataset covering the full ranges of design parameters. The present study considered building materials, their thickness, building shape, and occupant schedule as design variables since building energy performance is sensitive to these variables. Then, the results of the energy simulations were implemented into a set of regression equation to predict the energy consumption in each design scenario. The difference between regression-predicted and DOE-simulated annual building energy consumption are largely within 5%. It is envisioned that the developed regression models can be utilized to estimate the energy savings in the early stages of the design when different building schemes and design concepts are being considered. Keywords: eQUEST simulation, DOE-2 simulation, Monte Carlo simulation, Regression equations, Building energy performance

Shams Amiri, Shideh

36

A Gradual Compositional Change from Samoan Shield to Rejuvenated Lavas?  

NASA Astrophysics Data System (ADS)

The geochemical evolution of intraplate volcanoes is often compared to the archetypal model derived from Hawaiian volcanoes that involves a mantle plume source with multiple components. In Samoa, a range in rock types, ages, and isotopic compositions have been obtained across a number of volcanic seamounts and islands. However, due to dense vegetation on the islands, stratigraphic relations are not well known, and therefore a sequence for the construction of Samoan volcanoes is not as well-defined as in Hawaii. On the three largest islands, a shield and a rejuvenated stage have been defined, whereas the existence of a post-shield stage has been suggested and questioned (Natland and Turner, 1985). Moreover, the existing shield isotopic compositions (particularly Sr) are distinct, spanning a larger range than in Hawaii. Tutuila only hosts a small amount of rejuvenated lavas, but they are similar to those of Upolu, and there is an isotopic and compositional overlap between Tutuila shield volcanics and the Upolu lavas. On the island of Upolu, roughly half the surface area is covered in rejuvenated lavas, while the other half consists of shield stage lavas. The shield lavas around Fagaloa Bay are compositionally similar to some of the Tutuila lavas. On the island of Savaii, rejuvenated volcanism covers nearly the entire island, showing similar compositions to Upolu rejuvenated volcanism. We here present new data for samples from a deep canyon in the interior of Savaii, which form the missing link in understanding the geochemical sequence of Samoan volcanic construction. In this canyon, an isotopically distinct composition is found that resembles the composition of Fagaloa lavas on Upolu, instead of the extremely radiogenic Sr isotope compositions dredged from the submarine base of Savaii that represent the early shield stage. In Fagaloa Bay, a slope break on the mountainside has been suggested to form the outline of a crater along which late-stage evolved lavas such as trachytes erupted. A similar slope break is found in the canyon sampled on Savaii, and trachytes have previously been reported as cobbles in the draining river. Therefore, we infer that early shield volcanism in Savaii erupted extremely radiogenic Sr isotope compositions, and that by the end of shield building, compositions had changed to a composition similar to Upolu's Fagaloa. Some of the samples have Pb-Sr isotope compositions between Upolu and rejuvenated lavas, while their trace element compositions correspond to those of rejuvenated lavas. Thus, it appears that during the final stages of shield building, a shift to rejuvenated composition takes place. This contrasts with the definition of rejuvenated volcanism in Samoa, based on erosional contacts, and suggests rejuvenated source material may be sampled before the volcanic rejuvenation really occurs.

Konter, J. G.; Jackson, M. G.; Koppers, A. A.

2013-12-01

37

A comparative study on the shielding effect of tree, concrete building on direct lightning strokes to medium voltage distribution line  

Microsoft Academic Search

Lightning overvoltages are responsible for the majority of faults and outages that occur in Medium Voltage (MV) distribution networks. The overhead lines can be protected from the above phenomena with adequate installation of surge arresters and shield wires. Insulation enhancement can also play a significant role in minimizing outage rates of the lines, though it will not be so effective.

M. A. Omidiora; M. Lehtonen

2008-01-01

38

The Immature Stages and Shelter Building Behavior of Falgo Jeconia Ombra Evans, 1955 in eastern Ecuador (Lepidoptera: Hesperiidae: Hesperiinae)  

PubMed Central

We describe the immature stages and shelter building behavior of Falga jeconia ombra Evans, 1955 from eastern Ecuador. Chusquea scandens (Poaceae, Bambusoidea) is the larval food plant. Larvae in all stadia build shelters and forcibly eject frass with the aid of an anal comb. Later instars possess an eversible prothoracic “neck” gland. Larvae are associated with moving water. PMID:19613872

Greeney, Harold F.; Warren, Andrew D.

2009-01-01

39

Analysis of shield tunnel  

Microsoft Academic Search

SUMMARY This paper proposes a two-dimensional finite element model for the analysis of shield tunnels by taking into account the construction process which is divided into four stages. The soil is assumed to behave as an elasto-plastic medium whereas the shield is simulated by beam-joint discontinuous model in which curved beam elements and joint elements are used to model the

W. Q. Ding; Z. Q. Yue; L. G. Tham; H. H. Zhu; C. F. Lee; T. Hashimoto

2004-01-01

40

Analysis of shield tunnel  

Microsoft Academic Search

This paper proposes a two-dimensional finite element model for the analysis of shield tunnels by taking into account the construction process which is divided into four stages. The soil is assumed to behave as an elasto-plastic medium whereas the shield is simulated by beam-joint discontinuous model in which curved beam elements and joint elements are used to model the segments

W. Q. Ding; Z. Q. Yue; L. G. Tham; H. H. Zhu; C. F. Lee; T. Hashimoto

2004-01-01

41

Development of a methodology for defining whole-building energy design targets for commercial buildings: Phase 2, Development concept stage report  

SciTech Connect

The Whole-Building Energy Design Targets project is being conducted for the US Department of Energy (DOE) by the Pacific Northwest Laboratory (PNL). The objective of the project is to develop a flexible methodology for setting energy performance guidelines with which architects, engineers, planners, and owners can assess energy efficiency in commercial building design. This volume, the third in the four-volume report on the Targets project concept stage, contains the minutes of the workshops as well as summaries of the expert's written comments prepared at the close of each workshop. In Section 2, the building energy simulation workshop is summarized. Section 3 provides a summary of the building cost workshop.

Jones, J.W. (American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., Atlanta, GA (USA)); Deringer, J.J. (Deringer Group, Riva, MD (USA)); Hall, J.D. (American Inst. of Architects, Washington, DC (USA)) (comps.)

1990-09-01

42

Early Stage Design Decisions: The Way to Achieve Sustainable Buildings at Lower Costs  

PubMed Central

The construction industry attempts to produce buildings with as lower environmental impact as possible. However, construction activities still greatly affect environment; therefore, it is necessary to consider a sustainable project approach based on its performance. Sustainability is an important issue to consider in design, not only due to environmental concerns but also due to economic and social matters, promoting architectural quality and economic advantages. This paper aims to identify the phases through which a design project should be developed, emphasising the importance and ability of earlier stages to influence sustainability, performance, and life cycle cost. Then, a selection of sustainability key indicators, able to be used at the design conceptual phase and able to start predicting environmental sustainability performance of buildings is presented. The output of this paper aimed to enable designers to compare and evaluate the consequences of different design solutions, based on preliminary data, and facilitate the collaboration between stakeholders and clients and eventually yield a sustainable and high performance building throughout its life cycle. PMID:24578630

Bragança, Luís; Vieira, Susana M.; Andrade, Joana B.

2014-01-01

43

Shielding analysis of a small compact space nuclear reactor  

Microsoft Academic Search

The SP-100 reactor, currently in its developmental stage, has a layered tungsten-lithium hydride shield. Studies indicate that this shield configuration is the lightest weight shield. This configuration and three other shielding concepts were analyzed to determine the lightest shield and to determine the shield configuration with the smallest volume. The other concepts were a boron carbide-beryllium layered shield, and a

Lee L. Woodrow Jr.

1987-01-01

44

Characterization of organic air emissions from the Certification and Segregation Building and Air Support Weather Shield II at the Radioactive Waste Management Complex  

SciTech Connect

During the latter part of Fiscal Year (FY-92), a task was initiated to characterize the organic air emissions from the Certification and Segregation (C and S) Building [Waste Management Facility (WMF) 612] and the Air Support Weather Shield II (ASWS II or ASB II) (WMF 711) at the Radioactive Waste Management Complex (RWMC). The purpose of this task, titled the RWMC Organic Air Emissions Evaluation Task, was to identify and quantify the volatile organic compounds (VOCS) present in the ambient air in these two facilities and to estimate the organic air emissions. The VOCs were identified and quantified by implementing a dual method approach using two dissimilar analytical methodologies, Open-Path Fourier Transform Infrared Spectroscopy (OP-FTIR) and SUMMA canister sampling, following the US Environmental Protection Agency (EPA) analytical method TO-14. The data gathered were used in conjunction with the building`s ventilation rate to calculate an estimated organic air emissions rate. This report presents the data gathered during the performance of this task and relates the data to the relevant regulatory requirements.

Shoop, D.S.; Jackson, J.M.; Jolley, J.G.; Izbicki, K.J.

1994-12-01

45

Toward better soft tissue sarcoma staging: building on American Joint Committee on Cancer staging systems versions 6 and 7  

PubMed Central

Background Based on review of patient data in case conferences over time, we hypothesized that clinically relevant data are omitted in routine soft tissue sarcoma staging. Methods We examined subsets of the Memorial Sloan-Kettering Cancer Center soft tissue sarcoma database with respect to criteria of the AJCC versions 6 (2002) and 7 (2010) staging systems and examined their clinical outcomes. Results Relapse-free survival decreases with increasing primary tumor size in four categories, versus two categories used in AJCC 6 and 7 staging. Disease-specific survival decreases over three categories. Conversely, omission of tumor depth as a prognostic factor in version 7 appears supported, since tumor depth is not an independent risk factor for disease-specific survival by multivariate analysis. Patients with nodal disease and no other metastases fare better than patients with other metastases, but have inferior outcomes compared to patients with large high-grade tumors without nodal metastasis. Multivariate analysis identified size, site, grade, age, nodal metastatic disease and other metastatic disease as independent risk factors for disease-specific survival. Version 6 and 7 criteria are tacit regarding anatomic site and histology for tumors with identical FNCLCC grade. Conclusions Improved patient risk assessment may be achieved by staging using a larger number of size categories. Staging system refinements come at the cost of a larger number of staging categories. Histology or site-specific staging systems, nomograms or Bayesian belief networks may provide more accurate means to assess clinical outcomes. PMID:23775410

Moraco, Nicole; Antonescu, Cristina R.; Hameed, Meera; Pinkhasik, Alisa; Singer, Samuel; Brennan, Murray F.

2014-01-01

46

A New Approach to Predicting the Thermal Environment in Buildings at the Early Design Stage. Building Research Establishment Current Paper 2/74.  

ERIC Educational Resources Information Center

The paper argues that existing computer programs for thermal predictions do not produce suitable information for architects, particularly at the early stages of design. It reviews the important building features that determine the thermal environment and the need for heating and cooling plant. Graphical design aids are proposed, with examples to…

Milbank, N. O.

47

A review of "The Guild and Guild Buildings of Shakespeare's Stratford: Society, Religion, Education and Stage" by J. R. Mulryne  

E-print Network

: Society: Religion, Education and Stage. Farnham, Surrey: Ashgate Publishing Limited, 2012. xiv + 270 pp. $119.95. Review by Scott K. Oldenburg, Tulane University. This book brings into conversation historical, literary, and ar- chaeological studies... of the actual archi- tecture of the Guildhall and its surrounds. Kate Giles and Jonathan Clark provide an archaeological study of the building, revealing the ways in which the buildings were not only important to the religious identity of the town but also a...

Oldenburg, Scott K.

2015-01-01

48

Two-stage adaptive cutoff design for building and validating a prognostic biomarker signature.  

PubMed

Cancer biomarkers are frequently evaluated using archived specimens collected from previously conducted therapeutic trials. Routine collection and banking of high quality specimens is an expensive and time-consuming process. Therefore, care should be taken to preserve these precious resources. Here, we propose a novel two-stage adaptive cutoff design that affords the possibility to stop the biomarker study early if an evaluation of the model performance is unsatisfactory at an early stage, thereby allowing one to preserve the remaining specimens for future research. In addition, our design integrates important elements necessary to meet statistical rigor and practical demands for developing and validating a prognostic biomarker signature, including maintaining strict separation between the datasets used to build and evaluate the model and producing a locked-down signature to facilitate future validation. We conduct simulation studies to evaluate the operating characteristics of the proposed design. We show that under the null hypothesis when the model performance is deemed undesirable, the proposed design maintains type I error at the nominal level, has high probabilities of terminating the study early, and results in substantial savings in specimens. Under the alternative hypothesis, power is generally high when the total sample size and the targeted degree of improvement in prediction accuracy are reasonably large. We illustrate the use of the procedure with a dataset in patients with diffuse large-B-cell lymphoma. The practical aspects of the proposed designs are discussed. Published 2014. This article is a U.S. Government work and is in the public domain in the USA. PMID:25263614

Polley, Mei-Yin C; Polley, Eric C; Huang, Erich P; Freidlin, Boris; Simon, Richard

2014-12-20

49

Rethinking Client Resistance: A Narrative Approach to Integrating Resistance into the Relationship-Building Stage of Counseling  

ERIC Educational Resources Information Center

This article presents a review of traditional definitions of resistance and then presents a conceptualization of client resistance from a narrative perspective. The author makes recommendations/or using techniques consistent with narrative therapy to address client resistance during the relationship-building stage. These recommendations are…

Gold, Joshua M.

2008-01-01

50

Research of consolidation settlement caused by shield tunnel construction  

Microsoft Academic Search

The ground settlement caused by shield tunnel construction increased gradually over time. The long-term settlement caused by shield tunnel construction was divided into three stages. The stage 2 between the end of shield tunnel construction and the beginning of subway operation was emphatically analyzed. The research methods in stage 2 were summarized as follows: the predict method based on measured

Wei Gang; Wei Xin-jiang

2011-01-01

51

Modular shield  

DOEpatents

A modular system for containing projectiles has a sheet of material including at least a polycarbonate layer held by a metal frame having a straight frame member corresponding to each straight edge of the sheet. Each frame member has a U-shaped shield channel covering and holding a straight edge of the sheet and an adjacent U-shaped clamp channel rigidly held against the shield channel. A flexible gasket separates each sheet edge from its respective shield channel; and each frame member is fastened to each adjacent frame member only by clamps extending between adjacent clamp channels.

Snyder, Keith W. (Sandia Park, NM)

2002-01-01

52

Shielding analysis of a small compact space nuclear reactor. Final report  

Microsoft Academic Search

The SP-100 reactor concept, currently in its developmental stage, has layered tungsten - lithium hydride shield. Studies indicate that this shield configuration is the lightest weight shield. This configuration and three other shielding concepts were analyzed to determine the lightest shield and to determine the shield configuration with the smallest volume. The other three concepts were a boron carbide -

1987-01-01

53

PROVING EXPERIMENTS AND ANALYSIS OF ROOFTOP HEAT SHIELD EXPERIMENT WITH WATER CONTAIN CONCRETE BOAD THAT USES ELEMENTARY SCHOOL BUILDING  

NASA Astrophysics Data System (ADS)

In this study, the reduction effect of the heat inflow on the rooftop and the indoor thermal environment was measured by using the elementary school building, the rooftop of the bilding was covered with the water contain concrete boards. And, conserve energy effect and effectiveness for the indoor thermal environment improvement were evaluated. The effect of the decrease of the surface temperature and the slab side temperature at water contain concrete boad plot remarkably from the measurement result during the July-September of 2010, the temperatures decrease 22°C at the surface, 15°C at the waterproof layer surface that was caused compared with the gravel covered roof. The water contain concrete boards plot always drove the ceiling side temperature and the indoor temperature low as a result of comparing with the indoor condition of the control plot. The temperature fluctuate was small at time that opened the window and ventilated, and ventilation was discontinued, it became big temperatures fluctuate. The effect of the decrease of 0.5°C in PMV and 0.5 in WBGT was caused while the room had sealed up, and the effect of the decrease of 0.3 in WBGT was caused while the ventilated state.

Yamada, Hiroyuki; Tanaka, Akinori; ??, ??; Okuda, Yoshio; Koyama, Hiroyuki; Hada, Yuuichi

54

Source components of the Gran Canaria (Canary Islands) shield stage magmas: evidence from olivine composition and Sr-Nd-Pb isotopes  

NASA Astrophysics Data System (ADS)

The Canary Island primitive basaltic magmas are thought to be derived from an HIMU-type upwelling mantle containing isotopically depleted (NMORB)-type component having interacted with an enriched (EM)-type component, the origin of which is still a subject of debate. We studied the relationships between Ni, Mn and Ca concentrations in olivine phenocrysts (85.6-90.0 mol.% Fo, 1,722-3,915 ppm Ni, 1,085-1,552 ppm Mn, 1,222-3,002 ppm Ca) from the most primitive subaerial and ODP Leg 157 high-silica (picritic to olivine basaltic) lavas with their bulk rock Sr-Nd-Pb isotope compositions (87Sr/86Sr = 0.70315-0.70331, 143Nd/144Nd = 0.51288-0.51292, 206Pb/204Pb = 19.55-19.93, 207Pb/204Pb = 15.60-15.63, 208Pb/204Pb = 39.31-39.69). Our data point toward the presence of both a peridotitic and a pyroxenitic component in the magma source. Using the model (Sobolev et al. in: Science 316:412-417, 2007) in which the reaction of Si-rich melts originated during partial melting of eclogite (a high pressure product of subducted oceanic crust) with ambient peridotitic mantle forms olivine-free reaction pyroxenite, we obtain an end member composition for peridotite with 87Sr/86Sr = 0.70337, 143Nd/144Nd = 0.51291, 206Pb/204Pb = 19.36, 207Pb/204Pb = 15.61 and 208Pb/204Pb = 39.07 (EM-type end member), and pyroxenite with 87Sr/86Sr = 0.70309, 143Nd/144Nd = 0.51289, 206Pb/204Pb = 20.03, 207Pb/204Pb = 15.62 and 208Pb/204Pb = 39.84 (HIMU-type end member). Mixing of melts from these end members in proportions ranging from 70% peridotite and 30% pyroxenite to 28% peridotite and 72% pyroxenite derived melt fractions can generate the compositions of the most primitive Gran Canaria shield stage lavas. Combining our results with those from the low-silica rocks from the western Canary Islands (Gurenko et al. EPSL 277:514-524, 2009), at least four distinct components are required. We propose that they are (1) HIMU-type pyroxenitic component (representing recycled ocean crust of intermediate age) from the plume center, (2) HIMU-type peridotitic component (ancient recycled ocean crust stirred into the ambient mantle) from the plume margin, (3) depleted, MORB-type pyroxenitic component (young recycled oceanic crust) in the upper mantle entrained by the plume, and (4) EM-type peridotitic component from the asthenosphere or lithosphere above the plume center.

Gurenko, Andrey A.; Hoernle, Kaj A.; Sobolev, Alexander V.; Hauff, Folkmar; Schmincke, Hans-Ulrich

2010-05-01

55

Recycled Component in the Canary Plume: Constraints From Olivine Phenocryst Composition and Radiogenic Isotopes in the Shield Stage Lavas From the Canary Islands  

NASA Astrophysics Data System (ADS)

One of the major geochemical challenges in understanding the dynamics of mantle melting is to identify the components involved in magma genesis. A contribution from recycled lithosphere is commonly proposed but still the subject of considerable debate. The Canary plume is one of the few plumes that can be traced all the way to the core-mantle boundary with seismic tomography [1], making it an excellent location for studying the deep crustal recycling. Trace element and isotopic signatures of the mafic magmas erupted on the Canary Islands require partial melting of a time-integrated high U/Pb (HIMU)-type mantle source, whose origin is attributed to the recycling of less than 2 Ga old oceanic crust [1,2]. We studied the most primitive picritic through alkali basaltic to basanitic subaerial lavas from Gran Canaria, Tenerife, La Gomera and La Palma shield stages, as well as submarine basaltic hyaloclastites drilled during ODP Leg 157 in the submarine clastic apron of Gran Canaria. In accordance with the experimental results [3], these volcanic rocks could be formed by the greatest degree of partial melting of the source rocks. The lavas are moderately enriched in light rare earth elements, Nb, Ta, and depleted in K and Pb, resembling HIMU-type magmas from ocean islands such as Mangaia and St. Helena. The Sr-Nd-Pb isotope data (87Sr/86Sr = 0.7030-0.7033, 143Nd/144Nd = 0.51288-0.51293, 206Pb/204Pb = 19.49-20.27, 207Pb/204Pb = 15.59-15.66, 208Pb/204Pb = 39.21-39.81) and the relationship between Sr isotopes in whole rocks and O isotopes in olivine phenocrysts (delta-18O = 4.3-5.8+/-0.3 permil) rule out extensive magma contamination within the crust [4]. Variations of Ni concentrations in early crystallized olivine phenocrysts and coexisting melts [5] were used to quantify the amount of recycled material involved in the Canary plume. The observed large, systematic inter- and intra-island variations of Ni in Ol phenocrysts exceeding the obtained 2-sigma analytical error of +/-0.01 wt.% NiO cannot be explained by olivine fractionation. Furthermore, strong positive correlation of Ni/MgO with 87Sr/86Sr (R = 0.86) and negative correlation with 206Pb/204Pb isotopic ratios (R = 0.61) suggest that significant amounts of a recycled component appear to be involved in partial melting of the Canary plume increasing from Tenerife through La Gomera and La Palma to Gran Canaria. The largest amount of the recycled component was found in the ODP Leg 157 hyaloclastites. References: [1] Montelli et al. (2004) Science 303, 338-343; [2] Hoernle et al. (1991) EPSL 106, 44-63; [3] Wyllie (1988) JGR 93, 4171-4181; [4] Gurenko et al. (2005) GCA, submitted manuscript; [5] Sobolev et al. (2005) Nature 434, 590-597.

Gurenko, A.; Sobolev, A.; Hoernle, K.; Schmincke, H.

2005-12-01

56

Astronomers See First Stages of Planet-Building Around Nearby Star  

NASA Astrophysics Data System (ADS)

Interstellar travelers might want to detour around the star system TW Hydrae to avoid a messy planetary construction site. Astronomer David Wilner of the Harvard-Smithsonian Center for Astrophysics (CfA) and his colleagues have discovered that the gaseous protoplanetary disk surrounding TW Hydrae holds vast swaths of pebbles extending outward for at least 1 billion miles. These rocky chunks should continue to grow in size as they collide and stick together until they eventually form planets. Dust Disk Graphic Artist's Conception of Dusty Disk Around Young Star TW Hydrae CREDIT: Bill Saxton, NRAO/AUI/NSF (Click on image for larger version 1.8 MB) "We're seeing planet building happening right before our eyes," said Wilner. "The foundation has been laid and now the building materials are coming together to make a new solar system." Wilner used the National Science Foundation's Very Large Array to measure radio emissions from TW Hydrae. He detected radiation from a cold, extended dust disk suffused with centimeter-sized pebbles. Such pebbles are a prerequisite for planet formation, created as dust collects together into larger and larger clumps. Over millions of years, those clumps grow into planets. "We're seeing an important step on the path from interstellar dust particles to planets," said Mark Claussen (NRAO), a co-author on the paper announcing the discovery. "No one has seen this before." A dusty disk like that in TW Hydrae tends to emit radio waves with wavelengths similar to the size of the particles in the disk. Other effects can mask this, however. In TW Hydrae, the astronomers explained, both the relatively close distance of the system and the stage of the young star's evolution are just right to allow the relationship of particle size and wavelength to prevail. The scientists observed the young star's disk with the VLA at several centimeter-range wavelengths. "The strong emission at wavelengths of a few centimeters is convincing evidence that particles of about the same size are present," Claussen said. Not only does TW Hydrae show evidence of ongoing planet formation, it also shows signs that at least one giant planet may have formed already. Wilner's colleague, Nuria Calvet (CfA), has created a computer simulation of the disk around TW Hydrae using previously published infrared observations. She showed that a gap extends from the star out to a distance of about 400 million miles - similar to the distance to the asteroid belt in our solar system. The gap likely formed when a giant planet sucked up all the nearby material, leaving a hole in the middle of the disk. Located about 180 light-years away in the constellation Hydra the Water Snake, TW Hydrae consists of a 10 million-year-old star about four-fifths as massive as the Sun. The protoplanetary disk surrounding TW Hydrae contains about one-tenth as much material as the Sun -- more than enough to form one or more Jupiter-sized worlds. "TW Hydrae is unique," said Wilner. "It's nearby, and it's just the right age to be forming planets. We'll be studying it for decades to come." This research was published in the June 20, 2005, issue of the Astrophysical Journal Letters. Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for Astrophysics (CfA) is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe. The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

2005-06-01

57

Simulations of ELF magnetic shields  

Microsoft Academic Search

This paper describes a multistage algorithm for efficient calculation of magnetic flux contours, for optimizing the design\\u000a of structural magnetic shielding. It is part II of the article presented in Pekar and Netzer (2006). The Environmentalist. The multi-stage algorithm enables albeit medium-power computer system to calculate the effect of shielding materials with\\u000a a given geometry, in a reasonable timeframe without

Josef Pekar; Moshe Netzer; Yekutiel Pekar

2007-01-01

58

Thermocouple shield  

DOEpatents

A thermocouple shield for use in radio frequency fields. In some embodiments the shield includes an electrically conductive tube that houses a standard thermocouple having a thermocouple junction. The electrically conductive tube protects the thermocouple from damage by an RF (including microwave) field and mitigates erroneous temperature readings due to the microwave or RF field. The thermocouple may be surrounded by a ceramic sheath to further protect the thermocouple. The ceramic sheath is generally formed from a material that is transparent to the wavelength of the microwave or RF energy. The microwave transparency property precludes heating of the ceramic sheath due to microwave coupling, which could affect the accuracy of temperature measurements. The ceramic sheath material is typically an electrically insulating material. The electrically insulative properties of the ceramic sheath help avert electrical arcing, which could damage the thermocouple junction. The electrically conductive tube is generally disposed around the thermocouple junction and disposed around at least a portion of the ceramic sheath. The concepts of the thermocouple shield may be incorporated into an integrated shielded thermocouple assembly.

Ripley, Edward B. (Knoxville, TN)

2009-11-24

59

The MIT Design Advisor : simple and rapid energy simulation of early-stage building designs  

E-print Network

Simulation tools, when applied early in the design process, can considerably reduce the energy demand of newly constructed buildings. For a simulation tool to assist with design, it must be easy to use, provide feedback ...

Urban, Bryan J. (Bryan James)

2007-01-01

60

Drip Shield Emplacement Gantry Concept  

SciTech Connect

This design analysis has shown that, on a conceptual level, the emplacement of drip shields is feasible with current technology and equipment. A plan for drip shield emplacement was presented using a Drip Shield Transporter, a Drip Shield Emplacement Gantry, a locomotive, and a Drip Shield Gantry Carrier. The use of a Drip Shield Emplacement Gantry as an emplacement concept results in a system that is simple, reliable, and interfaces with the numerous other exising repository systems. Using the Waste Emplacement/Retrieval System design as a basis for the drip shield emplacement concept proved to simplify the system by using existing equipment, such as the gantry carrier, locomotive, Electrical and Control systems, and many other systems, structures, and components. Restricted working envelopes for the Drip Shield Emplacement System require further consideration and must be addressed to show that the emplacement operations can be performed as the repository design evolves. Section 6.1 describes how the Drip Shield Emplacement System may use existing equipment. Depending on the length of time between the conclusion of waste emplacement and the commencement of drip shield emplacement, this equipment could include the locomotives, the gantry carrier, and the electrical, control, and rail systems. If the exisiting equipment is selected for use in the Drip Shield Emplacement System, then the length of time after the final stages of waste emplacement and start of drip shield emplacement may pose a concern for the life cycle of the system (e.g., reliability, maintainability, availability, etc.). Further investigation should be performed to consider the use of existing equipment for drip shield emplacement operations. Further investigation will also be needed regarding the interfaces and heat transfer and thermal effects aspects. The conceptual design also requires further design development. Although the findings of this analysis are accurate for the assumptions made, further refinements of this analysis are needed as the project parameters change. The designs of the drip shield, the Emplacement Drift, and the other drip shield emplacement equipment all have a direct effect on the overall design feasibility.

Silva, R.A.; Cron, J.

2000-03-29

61

The influence of immersion and presence in early stage engineering designing and building  

E-print Network

This paper explores the role of a designer's sense of engagement in early stage design. In the field of virtual reality, presence and immersion are standard measures of an individual's sense of engagement and involvement ...

Faas, Daniela

62

Visualizing the Shields Parameter  

NSDL National Science Digital Library

This is not so much an activity as it is a useful tool to build an activity around. I created an Excel spreadsheet that calculates the Shields parameter and the grain Reynolds number for a given set of conditions, then plots the resultant values on the Shields diagram. Thus, students can tweak the boundary shear stress value to calculate the stress required to move a given grain size in any fluid, under any gravitational conditions. It is a great way for them to understand how changes in fluid density and viscosity (water vs. air) affect initiation of motion, as well as the effects of grain size. I might use this in a lecture on initiation of motion, asking them to answer some basic questions (see attached example).

Tom Hickson

63

Performance of solar shields. [Skylab 1 micrometeoroid shield difficulties  

NASA Technical Reports Server (NTRS)

The loss of the micrometeoroid shield from the Orbital Workshop section of Skylab 1 about 63 seconds after lift-off, was the catalyst for a prodigious effort to develop a substitute for the passive portion of the thermal control system. An intensive effort is described in which numerous potential thermal shield materials were assessed, and during which period ten specific shield designs were developed and carried through various stages of development and test. Thermal shield materials data are discussed, including optical, strength, fatigue, outgassing, tackiness, ultraviolet radiation, and material memory properties. Specifically addressed are thermal shield materials selection criteria and the design, development, and test requirements associated with the successful development of Skylab thermal shields, and specifically the two thermal shields subsequently deployed over the exposed gold foil skin of the Orbital Workshop. Also considered are the general performance and thermal improvements provided by both the parasol design deployed by the Skylab 1 crew, and the sail design deployed by the Skylab 2 crew.

Schwinghamer, R. J.

1974-01-01

64

SNF shipping cask shielding analysis  

SciTech Connect

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.

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

1996-01-01

65

66. CORBELS, BLIND ARCHES & SHIELDS, COMMONS EAST WALL, LOOKING ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

66. CORBELS, BLIND ARCHES & SHIELDS, COMMONS EAST WALL, LOOKING EAST - Smithsonian Institution Building, 1000 Jefferson Drive, between Ninth & Twelfth Streets, Southwest, Washington, District of Columbia, DC

66

71. Joe Moore, Photographer. September, 1996. BEVATRON ROOF SHIELDING AND ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

71. Joe Moore, Photographer. September, 1996. BEVATRON ROOF SHIELDING AND BUILDING TRUSS STRUCTURE - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

67

E-beam-Cure Fabrication of Polymer Fiber/Matrix Composites for Multifunctional Radiation Shielding  

NASA Technical Reports Server (NTRS)

Aliphatic polymers were identified as optimum radiation polymeric shielding materials for building multifunctional structural elements. Conceptual damage-tolerant configurations of polyolefins have been proposed but many issues on the manufacture remain. In the present paper, we will investigate fabrication technologies with e-beam curing for inclusion of high-strength aliphatic polymer fibers into a highly cross-linked polyolefin matrix. A second stage of development is the fabrication methods for applying face sheets to aliphatic polymer closed-cell foams.

Wilson, John W.; Jensen, Brian J.; Thibeault, Sheila A.; Hou, Tan-Hung; Saether, Erik; Glaessgen, Edward H.; Humes, Donald H.; Chang, Chie K.; Badavi, Francis F.; Kiefer, Rrichard L.; Adams, Dan O.

2004-01-01

68

Skylab Solar Shield  

NASA Technical Reports Server (NTRS)

A sail like sunshade for possible use as a sunscreen for the Skylab Orbital Workshop (OWS) is shown being fabricated in the GE Building across the street from Johnson Space Center, Houston Texas. Three people help the steamstress feed the material through the sewing machine. The three-layered sunshade will be composed of a top layer of aluminized mylar, a middle layer of laminated nylon ripstop, and a bottom layer of thin nylon. Working on the sunshade are from left to right: Dale Gentry, Elizabeth Gauldin, Alyene Baker, and James H. Barnett Jr. Mrs. Baker, a GE employee, operates the double needle Singer sewing machine. Barnett is head of the Crew Equipment Development Section of JSC Crew Systems Division. Mrs. Gauldin is also with the Crew Systems Division. Gentry works for GE. The work shown here is part of the crash program underway to prepare a sunshield for Skylab to replace the orginal shield which was lost when Skylab 1 was launched on May 14, 1973. The improvised solar shield selected to be used will be carried to Earth orbit by the Skylab 2 crewman who will then deploy the reflective parasol to shade part of the OWS from the hot rays of the sun. Loss of the orginal sun shield has caused an overheating problem. in the Orbital Work Shop.

1973-01-01

69

THE SHIELD-BACKED BUG, PACHYCORIS STALLII UHLER (HETEROPTERA: SCUTELLERIDAE) - DESCRIPTION OF IMMATURE STAGES, EFFECT OF MATERNAL CARE ON NYMPHS, AND NOTES ON LIFE HISTORY  

Technology Transfer Automated Retrieval System (TEKTRAN)

The life history of Pachycoris stallii Uhler immatures was studied on its host plant, Croton californicus Muell.-Arg. Immature stages of the bug were described and illustrated. Pachycoris stallii is bi- or multivoltine and occurs in xeric areas with sandy soil where. Nymphs and adults feed on see...

70

Policy Building Blocks: Helping Policymakers Determine Policy Staging for the Development of Distributed PV Markets: Preprint  

SciTech Connect

There is a growing body of qualitative and a limited body of quantitative literature supporting the common assertion that policy drives development of clean energy resources. Recent work in this area indicates that the impact of policy depends on policy type, length of time in place, and economic and social contexts of implementation. This work aims to inform policymakers about the impact of different policy types and to assist in the staging of those policies to maximize individual policy effectiveness and development of the market. To do so, this paper provides a framework for policy development to support the market for distributed photovoltaic systems. Next steps include mathematical validation of the framework and development of specific policy pathways given state economic and resource contexts.

Doris, E.

2012-04-01

71

Rootless Shield -- Lava Flow  

USGS Multimedia Gallery

Rootless shields grow both in breadth and height through the accumulation of repeated overflows from the summits of the shields. In this photo, a stream of lava is flowing southward down the flank of this emergent shield....

72

Corium shield  

DOEpatents

A shield for restricting molten corium from flowing into a water sump disposed in a floor of a containment vessel includes upper and lower walls which extend vertically upwardly and downwardly from the floor for laterally bounding the sump. The upper wall includes a plurality of laterally spaced apart flow channels extending horizontally therethrough, with each channel having a bottom disposed coextensively with the floor for channeling water therefrom into the sump. Each channel has a height and a length predeterminedly selected for allowing heat from the molten corium to dissipate through the upper and lower walls as it flows therethrough for solidifying the molten corium therein to prevent accumulation thereof in the sump.

McDonald, Douglas B. (Pleasanton, CA); Buchholz, Carol E. (San Jose, CA)

1994-01-01

73

Advanced Multifunctional MMOD Shield: Radiation Shielding Assessment  

NASA Technical Reports Server (NTRS)

Deep space missions must contend with a harsh radiation environment Impacts to crew and electronics. Need to invest in multifunctionality for spacecraft optimization. MMOD shield. Goals: Increase radiation mitigation potential. Retain overall MMOD shielding performance.

Rojdev, Kristina; Christiansen, Eric

2013-01-01

74

Magnetic shielding  

DOEpatents

A magnetically-conductive filler material bridges the gap between a multi-part magnetic shield structure which substantially encloses a predetermined volume so as to minimize the ingress or egress of magnetic fields with respect to that volume. The filler material includes a heavy concentration of single-magnetic-domain-sized particles of a magnetically conductive material (e.g. soft iron, carbon steel or the like) dispersed throughout a carrier material which is generally a non-magnetic material that is at least sometimes in a plastic or liquid state. The maximum cross-sectional particle dimension is substantially less than the nominal dimension of the gap to be filled. An epoxy base material (i.e. without any hardening additive) low volatility vacuum greases or the like may be used for the carrier material. The structure is preferably exposed to the expected ambient magnetic field while the carrier is in a plastic or liquid state so as to facilitate alignment of the single-magnetic-domain-sized particles with the expected magnetic field lines.

Kerns, John A. (Livermore, CA); Stone, Roger R. (Walnut Creek, CA); Fabyan, Joseph (Livermore, CA)

1987-01-01

75

Advanced Multifunctional MMOD Shield: Radiation Shielding Assessment  

NASA Technical Reports Server (NTRS)

As NASA is looking to explore further into deep space, multifunctional materials are a necessity for decreasing complexity and mass. One area where multifunctional materials could be extremely beneficial is in the micrometeoroid orbital debris (MMOD) shield. A typical MMOD shield on the International Space Station (ISS) is a stuffed whipple shield consisting of multiple layers. One of those layers is the thermal blanket, or multi-layer insulation (MLI). By increasing the MMOD effectiveness of MLI blankets, while still preserving their thermal capabilities, could allow for a less massive MMOD shield. Thus, a study was conducted to evaluate concept MLI blankets for MMOD shields. In conjunction, these MLI blankets and the subsequent MMOD shields were also evaluated for their radiation shielding effectiveness towards protecting crew. These concepts were evaluated against the ISS MLI blankets and the ISS MMOD shield, which acted as the baseline. These radiation shielding assessments were performed using the high charge and energy transport software (HZETRN). This software is based on a one-dimensional formula of the Boltzmann transport equation with a straight-ahead approximation. Each configuration was evaluated against the following environments to provide a diverse view of radiation shielding effectiveness in most space environments within the heliosphere: August 1972 solar particle event, October 1989 solar particle event, 1982 galactic cosmic ray environment (during solar maximum), 1987 galactic cosmic ray environment (during solar minimum), and a low earth orbit environment in 1970 that corresponded to an altitude of 400 km and inclination of 51.6 . Both the absorbed dose and the dose equivalent were analyzed, but the focus of the discussion was on the dose equivalent since the data is most concerned with radiation shielding of the crew. The following paper outlines the evaluations performed and discusses the results and conclusions of this evaluation for radiation shielding effectiveness. Future work will focus on optimizing the radiation shielding properties for the MMOD shield. Submission

Rojdev, Kristina; Christiansen, Eric

2011-01-01

76

Modeling and Simulation of the ARES UPPER STAGE Transportation, Lifting, Stacking and Mating Operations Within the Vehicle Assembly Building at KSC  

NASA Technical Reports Server (NTRS)

This viewgraph presentation describes the modeling and simulation of the Ares Upper Stage Transportation, lifting, stacking, and mating operations within the Vehicle Assembly Building (VAB) at Kennedy Space Center (KSC). An aerial view of KSC Launch Shuttle Complex, two views of the Delmia process control layout, and an upper stage move subroutine and breakdown are shown. An overhead image of the VAB and the turning basin along with the Pegasus barge at the turning basin are also shown. This viewgraph presentation also shows the actual design and the removal of the mid-section spring tensioners, the removal of the AFT rear and forward tensioners tie downs, and removing the AFT hold down post and mount. US leaving the Pegasus Barge, the upper stage arriving at transfer aisle, upper stage receiving/inspection in transfer aisle, and an overhead view of upper stage receiving/inspection in transfer aisle are depicted. Five views of the actual connection of the cabling to the upper stage aft lifting hardware are shown. The upper stage transporter forward connector, two views of the rotation horizontal to vertical, the disconnection of the rear bolt ring cabling, the lowering of the upper stage to the inspection stand, disconnection of the rear bolt ring from the upper stage, the lifting of the upper stage and inspection of AFT fange, and the transfer of upper stage in an integrated stack are shown. Six views of the mating of the upper stage to the first stage are depicted. The preparation, inspection, and removal of the forward dome are shown. The upper stage mated on the integrated stack and crawler is also shown. This presentation concludes with A Rapid Upper Limb Assessment (RULA) utilizing male and female models for assessing risk factors to the upper extremities of human beings in an actual physical environment.

Kromis, Phillip A.

2010-01-01

77

Advanced Multifunctional MMOD Shield: Radiation Shielding Assessment  

NASA Technical Reports Server (NTRS)

As NASA is looking to explore further into deep space, multifunctional materials are a necessity for decreasing complexity and mass. One area where multifunctional materials could be extremely beneficial is in the micrometeoroid orbital debris (MMOD) shield. A typical MMOD shield on the International Space Station (ISS) is a stuffed whipple shield consisting of multiple layers. One of those layers is the thermal blanket, or multi-layer insulation (MLI). Increasing the MMOD effectiveness of MLI blankets, while still preserving their thermal capabilities, could allow for a less massive MMOD shield. Thus, a study was conducted to evaluate a concept MLI blanket for an MMOD shield. In conjunction, this MLI blanket and the subsequent MMOD shield was also evaluated for its radiation shielding effectiveness towards protecting crew. The overall MMOD shielding system using the concept MLI blanket proved to only have a marginal increase in the radiation mitigating properties. Therefore, subsequent analysis was performed on various conceptual MMOD shields to determine the combination of materials that may prove superior for radiation mitigating purposes. The following paper outlines the evaluations performed and discusses the results and conclusions of this evaluation for radiation shielding effectiveness.

Rojdev, Kristina; Christiansen, Eric

2013-01-01

78

Principles of quasistatic magnetic shielding with cylindrical and spherical shields  

Microsoft Academic Search

The basic principles that underlie materials-based quasistatic magnetic shielding are described. Shielding mechanisms are identified and shown in specific examples that involve long cylindrical and spherical shield geometries. Analytic results are given both for shields that enclose the shielded region and for shields that enclose the source. The two configurations are reciprocal in the sense that identical shields have identical

J. F. Hoburg; J. F. Hobug

1995-01-01

79

Meteoroid/Debris Shielding  

NASA Technical Reports Server (NTRS)

This report provides innovative, low-weight shielding solutions for spacecraft and the ballistic limit equations that define the shield's performance in the meteoroid/debris environment. Analyses and hypervelocity impact testing results are described that have been used in developing the shields and equations. Spacecraft shielding design and operational practices described in this report are used to provide effective spacecraft protection from meteoroid and debris impacts. Specific shield applications for the International Space Station (ISS), Space Shuttle Orbiter and the CONTOUR (Comet Nucleus Tour) space probe are provided. Whipple, Multi-Shock and Stuffed Whipple shield applications are described.

Christiansen, Eric L.

2003-01-01

80

NUCLEAR REACTOR SHIELD  

Microsoft Academic Search

A method for constructing radiation shields for reactors so that the ; reactor and shield assembly have a low weight is described. The reactor is ; assumed to have a core of fissionable material in which the fission process ; utilizes predominantly neutrons with a median energy of the order of 10⁵ ev. ; The shield has a first layer

A. Stathoplos; L. A. Wills

1963-01-01

81

Enhanced Whipple Shield  

NASA Technical Reports Server (NTRS)

A hypervelocity impact (HVI) Whipple Shield and a method for shielding a wall from penetration by high velocity particle impacts where the Whipple Shield is comprised of spaced apart inner and outer metal sheets or walls with an intermediate cloth barrier arrangement comprised of ceramic cloth and high strength cloth which are interrelated by ballistic formulae.

Crews, Jeanne L. (Inventor); Christiansen, Eric L. (Inventor); Williamsen, Joel E. (Inventor); Robinson, Jennifer R. (Inventor); Nolen, Angela M. (Inventor)

1997-01-01

82

Shielding and background reduction  

Microsoft Academic Search

The background spectrum in a Low Background intrinsic germanium detector was analysed. Different possible sources of background and the influence of the materials used as well as the thickness of shielding was studied. Lead, copper, nylon, delrin and teflon of different thicknessewere used. Too much shielding material could induce some gamma rays from neutron production in the shielding due to

R. Núñez-Lagos; A. Virto

1996-01-01

83

Consensus Building.  

ERIC Educational Resources Information Center

Discusses the use of a Multi-Attribute Consensus Building (MACB) technique to build consensus on a national model of educational outcomes and indicators. Describes the stages of consensus building and the tasks mandated in each stage, including the generation of input, the consensus conference, and the synthesis of consensus. (RJM)

Vanderwood, Michael L.; Erickson, Ron

1994-01-01

84

Rotating shielded crane system  

DOEpatents

A rotating, radiation shielded crane system for use in a high radiation test cell, comprises a radiation shielding wall, a cylindrical ceiling made of radiation shielding material and a rotatable crane disposed above the ceiling. The ceiling rests on an annular ledge intergrally attached to the inner surface of the shielding wall. Removable plugs in the ceiling provide access for the crane from the top of the ceiling into the test cell. A seal is provided at the interface between the inner surface of the shielding wall and the ceiling.

Commander, John C. (Idaho Falls, ID)

1988-01-01

85

Development of a methodology for defining whole-building energy design targets for commercial buildings: Phase 2, Development Concept Stage Report  

SciTech Connect

This report documents eight tasks performed as part of the Whole-Building Energy Design Targets project, in which detailed conceptual approaches were produced for each element of the proposed Targets model. The eight task reports together describe the important modules proposed for inclusion in the Targets model: input module, energy module, characteristic development moduel, building cost module, analysis control module, energy cost module, search routines module, and economic analysis module. 16 refs., 16 figs., 5 tabs.

McKay, H.N. (Illuminating Engineering Society of North America, New York, NY (USA)); Deringer, J.J. (American Inst. of Architects, Washington, DC (USA)); Jones, J.W. (American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., Atlanta, GA (USA)); Hall, J.D. (Deringer Group, Riva, MD (USA))

1990-09-01

86

Analysis on the safety of a concrete-masonry structure near to shield tunnel excavation  

Microsoft Academic Search

The shield tunnel excavation of a city subway under a building will influence its safety. In order to reduce the damages, settlements caused by shield tunnel construction must be controlled strictly. The different settlement of building has been investigated to obtain current parameters. By calculating the internal stress of the structure of building considering its weight, loads and different displacement

Dong-ping Qin; Ping He; Hai-yan Zhang; Cheng-hao Ma

2011-01-01

87

Estimation of the activation of local reactor shielding concretes  

Microsoft Academic Search

Many elements in reactor shielding concrete become radioactive due to interaction with neutrons during the operation of a nuclear reactor. These radioactive elements will build up over the time due to (n,?) reaction and contribute to the radioactive waste during decommissioning of the reactor, they will increase the dose from the inner part of the biological shielding (concrete) surrounding a

S. Alhajali; M. H. Kharita; B. Naoom; S. Yousef; M. AlNassar

2009-01-01

88

Intelligent buildings  

Microsoft Academic Search

The principal issues faced in intelligent building design and construction are presented. The components of the intelligent building are placed into four main categories-facilities management, information management, connectivity, and overall control-and each of these is examined. Multitenant shared services, the changing nature of building components, and the benefits of intelligent building management are briefly discussed. Six stages in the realization

B. M. Flax

1991-01-01

89

Low-Cost Shielding to Minimize Radiation Errors of Temperature Sensors in the Field  

Technology Transfer Automated Retrieval System (TEKTRAN)

The importance of shielding temperature sensors from solar radiation is understood, but there is a lack of prescriptive advice for plant scientists to build inexpensive, effective shields for replicated field experiments. Using general physical principles that govern radiation shielding, a number of...

90

Gamma ray detector shield  

DOEpatents

A gamma ray detector shield comprised of a rigid, lead, cylindrical-shaped vessel having upper and lower portions with an pneumatically driven, sliding top assembly. Disposed inside the lead shield is a gamma ray scintillation crystal detector. Access to the gamma detector is through the sliding top assembly.

Ohlinger, R.D.; Humphrey, H.W.

1985-08-26

91

Gamma ray detector shield  

Microsoft Academic Search

A gamma ray detector shield comprised of a rigid, lead, cylindrical-shaped vessel having upper and lower portions with an pneumatically driven, sliding top assembly. Disposed inside the lead shield is a gamma ray scintillation crystal detector. Access to the gamma detector is through the sliding top assembly.

R. D. Ohlinger; H. W. Humphrey

1985-01-01

92

Setting the Stage with Geometry: Lessons & Worksheets to Build Skills in Measuring Perimeter, Area, Surface Area, and Volume. Poster/Teaching Guide. Expect the Unexpected with Math[R  

ERIC Educational Resources Information Center

"Setting the Stage with Geometry" is a new math program aligned with the National Council of Teachers of Mathematics (NCTM) standards that is designed to help students in grades 6-8 build and reinforce basic geometry skills for measuring 2D and 3D shapes. Developed by The Actuarial Foundation, this program seeks to provide skill-building math…

Actuarial Foundation, 2013

2013-01-01

93

Development of a methodology for defining whole-building energy design targets for commercial buildings: Phase 2, Development Concept Stage Report  

SciTech Connect

The primary focus of the Whole-Building Energy Design Targets project is to develop a flexible methodology for setting target guidelines with which to assess energy efficiency in commercial building design. The proposed methodology has several innovative features. In this report, the authors document their work to define the software development concepts upon which the overall Targets methodology will be based. Three task reports are included here. Development of the user interface--that critical connection through which the human end-user (architect, engineer, planner, owner) will apply the methodology--is described in Section 2. In Section 3, the use of the software engineering process in Targets model development efforts is described. Section 4 provides details on the data and system integration task, in which interactions between and among all the major components, termed modules, of the Targets model were examined to determine how to put them together to create a methodology that is effective and easy to use. 4 refs., 26 figs.

Deringer, J.J. (American Inst. of Architects, Washington, DC (USA)); Hall, J.D. (Deringer Group, Riva, MD (USA)); Jones, J.W. (American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., New York, NY (USA)); McKay, H.N. (Illuminating Engineering Society of North America, New York, NY (USA)); Alley, P.K. (Pacific Northwest Lab., Richland, WA (USA))

1990-09-01

94

The Transtheoretical Stages of Change Model and Motivational Interviewing for Building Maternal Supportiveness in Cases of Sexual Abuse.  

ERIC Educational Resources Information Center

Describes use of the Stages of Change Model and Motivational Interviewing to enhance supportiveness of mothers in child intra-familial sexual abuse. Research indicates many mothers are ambivalent and vary in their levels of support; however, the crucial impact of maternal support on child adjustment and recovery has been emphasized. Further study…

Corcoran, Jacqueline

2002-01-01

95

Energy Performance Evaluation and Development of Control Strategies for the Air-conditioning System of a Building at Construction Stage  

E-print Network

system (ATC) and building management system (BMS). The software of control strategies and supervisory control and the corresponding hardware ICEBO2006, Shenzhen, China HVAC Technologies for Energy Efficiency, Vol. IV-8-1 are also needed... OF SYSTEM DIAGNOSIS AND CONTROL OPTIMIZERS Figure 3 shows the implementation architecture of ?Chiller Plant Control Optimizer? and the robust control strategies. All the DDC controllers of air systems are integrated into a LAN-based BMS. Supply air...

Wang, S.; Xu, X.; Ma, Z.

2006-01-01

96

Shielding against galactic cosmic rays  

NASA Technical Reports Server (NTRS)

Ions of galactic origin are modified but not attenuated by the presence of shielding materials. Indeed, the number of particles and the absorbed energy behind most shield materials increases as a function of shield thickness. The modification of the galactic cosmic ray composition upon interaction with shielding is the only effective means of providing astronaut protection. This modification is intimately conntected with the shield transport porperties and is a strong function of shield composition. The systematic behavior of the shield properites in terms of microscopic energy absorption events will be discussed. The shield effectiveness is examined with respect to convectional protection practice and in terms of a biological endpoint: the efficiency for reduction of the probability of transformation of shielded C3H1OT1/2 mouse cells. The relative advantage of developing new shielding technologies is discussed in terms of a shield performance as related to biological effect and the resulting uncertainty in estimating astronaut risk.

Schimmerling, W.; Wilson, J. W.; Nealy, J. E.; Thibeault, S. A.; Cucinotta, F. A.; Shinn, J. L.; Kim, M.; Kiefer, R.

1996-01-01

97

The Dalkon Shield debate.  

PubMed

The literature seems to have settled the controversy among physicians as to whether or not the Dalkon Shield is the real culprit in the relationship between IUD use and pelvic inflammatory disease (PID). This review of the literature suggests that all types of IUDs in use have the potential to enhance PID. The Dalkon Shield debate today is primarily between attorneys for A.H. Robins and attorneys for Plaintiffs who claim injury from PID and infected pregnancies. The National Law Journal on January 11, 1982 reported that in July 1979 a jury in Denver, Colorado awarded a patient $600,000 in compensatory damages and $6.2 million punitive damages against A.H. Robins, maker of the Dalkon Shield. Already verdicts and settlements against Robins in some 3200 cases have cost the company about $69 million. More than 1500 lawsuits are pending, seeking a total of $2.8 billion in compensatory and punitive damages from Robins. In view of this information another review of the literature is not superfluous. Clinical experience proved that the Dalkon Shield was the 1 IUD most likely not to be expelled. The disadvantages were pain on insertion and removal. Many of this doctor's patients, especially those who were nulliparous, experienced syncopal attacks on insertion. The clinical experience was also that the contraceptive failure rate was greater than the reported 1.1%. For these reasons Dalkon Shield insertions were stopped. Pelvic infection was not a determining factor in abandoning the use of the Dalkon Shield. A most damaging study for the Dalkon Shield appeared in June 1974. Christian reported 5 midtrimester maternal deaths and 7 cases of septic abortion associated with IUD usage. The Dalkon Shield was involved in 10 cases, and 2 cases involved the Lippes Loop. This report created suspicion that there might be something about the design of the Dalkon Shield that allows dissemination of infection. June 28, 1974 Robins voluntarily suspended domestic distribution of the Dalkon Shield at the request of the US Food and Drug Administration, but there was no recall of the device until September 1980. An extensive study in 1977 by Eschenbach et al. concluded that IUD users have a 4.4 times greater risk of developing PID than nonusers, and no particular type of IUD was found to be disproportionately associated with PID. Purrer et al. in 1979 published a 2nd in vitro study on IUD tails exposed to pathogenic bacteria. The study totally disagreed with the conclusions of Tatum that condemned the multifilament tail of the Dalkon Shield. In sum the Dalkon Shield debate is no longer of clinical significance. PMID:6851548

Goodhue, P A

1983-03-01

98

SHIELDING COMPUTER PROGRAM 04-2, REACTOR SHIELD ANALYSIS  

Microsoft Academic Search

Shielding Computer Program 04-2 is available for computing reactor-; shield weight and fast neutron and gamma ray dose rates in and around complex ; reactor-shield assemblies. Reaetor and shield geometries are described by ; combinations of regions formed by rotating rectangles or trapezoids about the ; reactor axis or by translating rectangles parallel to the reactor axis. ; Compositions are

W. E. Edwards; J. E. MacDonald; J. J. Loechler

1957-01-01

99

iSHIELD - A Line Source Application of SHIELD11  

SciTech Connect

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.

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

2006-04-27

100

9. BUILDING NO. 620B, FRICTION PENDULUM BUILDING. 29FOOT DROP TOWER ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

9. BUILDING NO. 620-B, FRICTION PENDULUM BUILDING. 29-FOOT DROP TOWER SITS BEHIND BLAST SHIELD IN FRONT OF BUILDING. - Picatinny Arsenal, 600 Area, Test Areas District, State Route 15 near I-80, Dover, Morris County, NJ

101

Alternate shield material feasibility  

SciTech Connect

The feasibility and cost/benefit of using materials other than stainless steel for in-vessel neutron shielding in large LMFBRs were investigated. Canned vibratorally compacted B/sub 4/C powder shields were found to be much more economical than stainless steel (a savings of $1.1M in loop plant designs and $9.4M in pool plant designs). The helium gas pressure buildup in B/sub 4/C shields placed around LMFBR in-vessel components (direct reactor heat exchangers in a loop reactor and intermediate heat exchangers in a pool reactor) would only be 0.04 atm after 40 y of reactor operation (with 80% dense powder). The irradiation-induced swelling of the B/sub 4/C would only be 0.002%. No adverse reactor impact would occur if the B/sub 4/C escaped from the B/sub 4/C shields.

Specht, E.R.; Levitt, L.B.

1984-04-01

102

Space Station MMOD Shielding  

NASA Technical Reports Server (NTRS)

This paper describes International Space Station (ISS) shielding for micrometeoroid orbital debris (MMOD) protection, requirements for protection, and the technical approach to meeting requirements. Current activities in MMOD protection for ISS will be described, including efforts to augment MMOD protection by adding shields on-orbit. Observed MMOD impacts on ISS elements such as radiators, modules and returned hardware will be described. Comparisons of the observed damage with predicted damage using risk assessment software will be made.

Christiansen, Eric

2006-01-01

103

Methods of Making Z-Shielding  

NASA Technical Reports Server (NTRS)

Methods of building Z-graded radiation shielding and covers. In one aspect, the method includes: providing a substrate surface having about medium Z-grade; plasma spraying a first metal having higher Z-grade than the substrate surface; and infusing a polymer layer to form a laminate. In another aspect, the method includes electro/electroless plating a first metal having higher Z-grade than the substrate surface. In other aspects, the methods include improving an existing electronics enclosure to build a Z-graded radiation shield by applying a temperature controller to at least part of the enclosure and affixing at least one layer of a first metal having higher Z-grade from the enclosure.

Thomsen, III, Donald Laurence (Inventor); Cano, Roberto J. (Inventor); Jensen, Brian J. (Inventor); Hales, Stephen J. (Inventor); Alexa, Joel A. (Inventor)

2014-01-01

104

Grounding and shielding in the accelerator environment  

SciTech Connect

Everyday features of the accelerator environment include long cable runs, high power and low level equipment sharing building space, stray electromagnetic fields and ground voltage differences between the sending and receiving ends of an installation. This paper pictures some Fermilab installations chosen to highlight significant features and presents practices, test methods and equipment that have been helpful in achieving successful shielding. Throughout the report are numbered statements aimed at summarizing good practices and avoiding pitfalls.

Kerns, Q.

1991-12-31

105

ARIES-CS Radial Builds and Compositions  

E-print Network

everywhere (no shield-only zones). · 1% nuclear heating in LT shield and/or VV. · Shield, VV, and magnet Configuration R = 8.25 m a = 1.85 m #12;08/30/2004 10 Internal VV #12;08/30/2004 11 Flibe/FS Radial Build (Water

106

Damaged Skylab Micrometeoroid Shield  

NASA Technical Reports Server (NTRS)

The Saturn V vehicle, carrying the unmarned orbital workshop for the Skylab-1 mission, lifted off successfully and all systems performed normally. Sixty-three seconds into flight, engineers in the operation support and control center saw an unexpected telemetry indication that signalled that damages occurred on one solar array and the micrometeoroid shield during the launch. The micrometeoroid shield, a thin protective cylinder surrounding the workshop protecting it from tiny space particles and the sun's scorching heat, ripped loose from its position around the workshop. This caused the loss of one solar wing and jammed the other. Still unoccupied, the Skylab was stricken with the loss of the heat shield and sunlight beat mercilessly on the lab's sensitive skin. Internal temperatures soared, rendering the station uninhabitable, threatening foods, medicines, films, and experiments. This image, taken during a fly-around inspection by the Skylab-2 crew, shows the damaged meteoroid shield being held by a thin aluminum strap entangled with green-hued remnants of the lost heat shield. The Marshall Space Flight Center (MSFC) developed, tested, rehearsed, and approved three repair options. These options included a parasol sunshade and a twin-pole sunshade to restore the temperature inside the workshop, and a set of metal cutting tools to free the jammed solar panel.

1973-01-01

107

Confirmatory survey of the staging area south of the RF-6 Building RMI Titanium Company, Ashtabula, Ohio  

SciTech Connect

The RMI Titanium Company's Plant in Ashtabula, Ohio, performed uranium metal extrusions for the Department of Energy (DOE) from 1962 to 1988 and for the Nuclear Regulatory Commission (NRC) until 1988. RMI has discontinued the uranium extrusion processes and has initiated the decontamination and decommissioning of the facilities and surrounding land areas. Prior to any decontamination of the plant facilities, a new office and laboratory facility must be constructed to relocate current activities. The objective of this survey was to confirm that the decontamination efforts by the licensee have been effective in meeting the current guidelines established for the decommissioning of this site. Background exposure rate measurements and soil sampling to determine baseline radionuclide concentrations, were conducted at eight locations in the Ashtabula area. A surface gamma scan was conducted in the staging area at 1--2 m intervals to identify locations of residual gross elevated activities. NaI(T1) gamma scintillation detectors, coupled to ratemeters with audible indicators, were used for these measurements.

Cotten, P.R.

1991-08-01

108

Confirmatory survey of the staging area south of the RF-6 Building RMI Titanium Company, Ashtabula, Ohio. Final report  

SciTech Connect

The RMI Titanium Company`s Plant in Ashtabula, Ohio, performed uranium metal extrusions for the Department of Energy (DOE) from 1962 to 1988 and for the Nuclear Regulatory Commission (NRC) until 1988. RMI has discontinued the uranium extrusion processes and has initiated the decontamination and decommissioning of the facilities and surrounding land areas. Prior to any decontamination of the plant facilities, a new office and laboratory facility must be constructed to relocate current activities. The objective of this survey was to confirm that the decontamination efforts by the licensee have been effective in meeting the current guidelines established for the decommissioning of this site. Background exposure rate measurements and soil sampling to determine baseline radionuclide concentrations, were conducted at eight locations in the Ashtabula area. A surface gamma scan was conducted in the staging area at 1--2 m intervals to identify locations of residual gross elevated activities. NaI(T1) gamma scintillation detectors, coupled to ratemeters with audible indicators, were used for these measurements.

Cotten, P.R.

1991-08-01

109

Dynamic rotating-shield brachytherapy  

PubMed Central

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 D90 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 192Ir-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 D2cc of the rectum, sigmoid colon, or bladder reached its tolerance equivalent dose in 2 Gy fractions (EQD2 with ?/? = 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 Ci192Ir source, and the average HR-CTV D90 was 78.9 Gy. In order to match the HR-CTV D90 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 D90 above IS + ICBT by an average of 16.3 Gy and 9.1 Gy, respectively. Conclusions: For cervical cancer patients, D-RSBT can boost HR-CTV D90 over IS + ICBT and S-RSBT without violating the tolerance doses to the bladder, rectum, or sigmoid. The D90 improvements from D-RSBT depend on the patient, the delivery time budget, and the applicator structure. PMID:24320489

Liu, Yunlong; Flynn, Ryan T.; Kim, Yusung; Yang, Wenjun; Wu, Xiaodong

2013-01-01

110

Dynamic rotating-shield brachytherapy  

SciTech Connect

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 ?/?= 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.Conclusions: For cervical cancer patients, D-RSBT can boost HR-CTV D{sub 90} over IS + ICBT and S-RSBT without violating the tolerance doses to the bladder, rectum, or sigmoid. The D{sub 90} improvements from D-RSBT depend on the patient, the delivery time budget, and the applicator structure.

Liu, Yunlong [Department of Electrical and Computer Engineering, University of Iowa, 4016 Seamans Center, Iowa City, Iowa 52242 (United States)] [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)] [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)] [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)] [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

111

WAKE SHIELD FACILITY FREE FLYER MATE TO CANISTER  

NASA Technical Reports Server (NTRS)

WAKE SHIELD FACILITY FREE FLYER MATE TO CANISTER KSC-96PC-2961.10 In NASA's Building AE on Cape Canaveral Air Station, the Wake Shield Facility-3 (WSF- 3) free-flyer is being mated to the carrier to complete the payload. The WSF-3 is one of two primary payloads on Space Shuttle Mission STS-80. The Shuttle Columbia is being prepared for liftoff on the final Shuttle flight of 1996 around Nov. 8 from Launch Pad 39B.

1996-01-01

112

WAKE SHIELD FACILITY FREE FLYER MATE TO CANISTER  

NASA Technical Reports Server (NTRS)

WAKE SHIELD FACILITY FREE FLYER MATE TO CANISTER KSC-96PC-2961.5 In NASA's Building AE on Cape Canaveral Air Station, the Wake Shield Facility-3 (WSF- 3) free-flyer is being mated to the carrier to complete the payload. The WSF-3 is one of two primary payloads on Space Shuttle Mission STS-80. The Shuttle Columbia is being prepared for liftoff on the final Shuttle flight of 1996 around Nov. 8 from Launch Pad 39B.

1996-01-01

113

WAKE SHIELD FACILITY FREE FLYER MATE TO CANISTER  

NASA Technical Reports Server (NTRS)

WAKE SHIELD FACILITY FREE FLYER MATE TO CANISTER KSC-96PC-2961.8 In NASA's Building AE on Cape Canaveral Air Station, the Wake Shield Facility-3 (WSF- 3) free-flyer is being mated to the carrier to complete the payload. The WSF-3 is one of two primary payloads on Space Shuttle Mission STS-80. The Shuttle Columbia is being prepared for liftoff on the final Shuttle flight of 1996 around Nov. 8 from Launch Pad 39B.

1996-01-01

114

Opportunity's Heat Shield Scene  

NASA Technical Reports Server (NTRS)

This image from NASA's Mars Exploration Rover Opportunity reveals the scene of the rover's heat shield impact. In this view, Opportunity is approximately 130 meters (427 feet) away from the device that protected it while hurtling through the martian atmosphere.

The rover spent 36 sols investigating how the severe heating during entry through the atmosphere affected the heat shield. The most obvious is the fact that the heat shield inverted upon impact.

This is the panoramic camera team's best current attempt at generating a true-color view of what this scene would look like if viewed by a human on Mars. It was generated from a mathematical combination of six calibrated, left-eye panoramic camera images acquired around 1:50 p.m. local solar time on Opportunity's sol 322 (Dec. 19, 2004) using filters ranging in wavelengths from 430 to 750 nanometers.

2005-01-01

115

Radiation shielding composition  

DOEpatents

A composition for use as a radiation shield. The shield is a concrete product containing a stable uranium aggregate for attenuating gamma rays and a neutron absorbing component, the uranium aggregate and neutron absorbing component being present in the concrete product in sufficient amounts to provide a concrete having a density between about 4 and about 15 grams/cm.sup.3 and which will at a predetermined thickness, attenuate gamma rays and absorb neutrons from a radioactive material of projected gamma ray and neutron emissions over a determined time period. The composition is preferably in the form of a container for storing radioactive materials that emit gamma rays and neutrons. The concrete container preferably comprises a metal liner and/or a metal outer shell. The resulting radiation shielding container has the potential of being structurally sound, stable over a long period of time, and, if desired, readily mobile.

Quapp, William J. (Idaho Falls, ID); Lessing, Paul A. (Idaho Falls, ID)

2000-12-26

116

Radiation shielding composition  

DOEpatents

A composition for use as a radiation shield. The shield is a concrete product containing a stable uranium aggregate for attenuating gamma rays and a neutron absorbing component, the uranium aggregate and neutron absorbing component being present in the concrete product in sufficient amounts to provide a concrete having a density between about 4 and about 15 grams/cm.sup.3 and which will at a predetermined thickness, attenuate gamma rays and absorb neutrons from a radioactive material of projected gamma ray and neutron emissions over a determined time period. The composition is preferably in the form of a container for storing radioactive materials that emit gamma rays and neutrons. The concrete container preferably comprises a metal liner and/or a metal outer shell. The resulting radiation shielding container has the potential of being structurally sound, stable over a long period of time, and, if desired, readily mobile.

Quapp, William J. (Idaho Falls, ID); Lessing, Paul A. (Idaho Falls, ID)

1998-01-01

117

Radiation shielding composition  

DOEpatents

A composition is disclosed for use as a radiation shield. The shield is a concrete product containing a stable uranium aggregate for attenuating gamma rays and a neutron absorbing component, the uranium aggregate and neutron absorbing component being present in the concrete product in sufficient amounts to provide a concrete having a density between about 4 and about 15 grams/cm{sup 3} and which will at a predetermined thickness, attenuate gamma rays and absorb neutrons from a radioactive material of projected gamma ray and neutron emissions over a determined time period. The composition is preferably in the form of a container for storing radioactive materials that emit gamma rays and neutrons. The concrete container preferably comprises a metal liner and/or a metal outer shell. The resulting radiation shielding container has the potential of being structurally sound, stable over a long period of time, and, if desired, readily mobile. 5 figs.

Quapp, W.J.; Lessing, P.A.

1998-07-28

118

Development and application of the DPLEX shield method: Results of experiments using shield and segment models and application of the method in tunnel construction  

Microsoft Academic Search

The DPLEX shield method employs a shield having a parallel link-type excavation mechanism to build shield tunnels of various cross-sectional shapes (rectangle, oval, etc.). The segment used with the DPLEX method has a rational cross-sectional shape, that is, a rounded rectangle obtained by putting together curved sections having different radius of curvature. This paper describes the results of experiments conducted

Y. Kashima; N. Kondo; M. Inoue

1996-01-01

119

Glove box shield  

DOEpatents

According to the present invention, a shield for a glove box housing radioactive material is comprised of spaced apart clamping members which maintain three overlapping flaps in place therebetween. There is a central flap and two side flaps, the side flaps overlapping at the interior edges thereof and the central flap extending past the intersection of the side flaps in order to insure that the shield is always closed when the user withdraws his hand from the glove box. Lead loaded neoprene rubber is the preferred material for the three flaps, the extent of lead loading depending upon the radiation levels within the glove box.

Brackenbush, Larry W. (Richland, WA); Hoenes, Glenn R. (Richland, WA)

1981-01-01

120

Composition for radiation shielding  

DOEpatents

A composition for use as a radiation shield. The shield has a depleted urum core for absorbing gamma rays and a bismuth coating for preventing chemical corrosion and absorbing gamma rays. Alternatively, a sheet of gadolinium may be positioned between the uranium core and the bismuth coating for absorbing neutrons. The composition is preferably in the form of a container for storing materials that emit radiation such as gamma rays and neutrons. The container is preferably formed by casting bismuth around a pre-formed uranium container having a gadolinium sheeting, and allowing the bismuth to cool. The resulting container is a structurally sound, corrosion-resistant, radiation-absorbing container.

Kronberg, James W. (Aiken, SC)

1994-01-01

121

SHIELDING COMPUTER PROGRAM 04-0, REACTOR SHIELD ANALYSIS  

Microsoft Academic Search

Shielding Computer Program 04-0 is available for computing reactor-; shield weight and fast neutron and gamma ray dose rates in and around complex ; resctorshield assemblies. Reactor and shield geometries are described by ; combinations of regions formed by rotating rectangles or trapezoids about the ; reactor axis or by translating rectangles parallel to the reactor axis. ; Compositions are

W. E. Edwards; J. E. MacDonald; B. Goldberg; K. Paine

1958-01-01

122

SHIELDING COMPUTER PROGRAM 04-1, REACTOR SHIELD ANALYSIS  

Microsoft Academic Search

Shielding Computer Program 04-1 is available for computing reactor-; shield weight and fast neutron and gamma ray dose rates in and around complex ; reactor-shield assemblies. Reactor and shleld geometries are described by ; combinations of regions formed by rotating rectangles or trapezoids about the ; reactor axis or by translating rectangles parallel to the reactor axis. ; Compositions are

W. E. Edwards; M. A. Capo; K. Paine

1958-01-01

123

Lightweight blast shield  

DOEpatents

A tandem warhead missile arrangement that has a composite material housing structure with a first warhead mounted at one end and a second warhead mounted near another end of the composite structure with a dome shaped composite material blast shield mounted between the warheads to protect the second warhead from the blast of the first warhead.

Mixon, Larry C. (Madison, AL); Snyder, George W. (Huntsville, AL); Hill, Scott D. (Toney, AL); Johnson, Gregory L. (Decatur, AL); Wlodarski, J. Frank (Huntsville, AL); von Spakovsky, Alexis P. (Huntsville, AL); Emerson, John D. (Arab, AL); Cole, James M. (Huntsville, AL); Tipton, John P. (Huntsville, AL)

1991-01-01

124

Shield against radiations  

SciTech Connect

This patent describes a shield against ionizing radiations that comprises at least one layer of an aggregate-containing cement-based conglomerate or an aggregate-containing cement-based mortar wherein the aggregate consists essentially of floated galena or mixtures thereof which at least one boron mineral.

Grifoni, S.

1988-02-23

125

President Clinton Defers Missile Shield Decision  

NSDL National Science Digital Library

President Clinton will announce in a speech at Georgetown University today that he will not begin the initial steps to deploy a national missile defense shield, leaving the final decision to his successor. The decision to not begin construction of a radar site in Alaska, designed to track incoming missiles, was apparently the product of several factors. These include the failure of recent tests, strong opposition from Russia and some US allies, and fears that any decision would inevitably become politicized with the election nearing. Vice-President Al Gore has expressed conditional support for a missile shield, while George W. Bush has called for an even more extensive system. The President made his decision after receiving competing advice on the missile shield. William S. Cohen, the defense secretary, had recommended Mr. Clinton begin, while Samuel R. Berger, the President's national security advisor, and others recommended against construction at this point. Work on the project will continue nonetheless, including additional tests of the "kill vehicle" and a new booster rocket. The next President will decide not only whether to build the radar station and other elements of a missile shield infrastructure, but also whether to field the system and break the 1972 Antiballistic Missile Treaty.

de Nie, Michael Willem.

126

WASTE TREATMENT BUILDING SYSTEM DESCRIPTION DOCUMENT  

SciTech Connect

The Waste Treatment Building System provides the space, layout, structures, and embedded subsystems that support the processing of low-level liquid and solid radioactive waste generated within the Monitored Geologic Repository (MGR). The activities conducted in the Waste Treatment Building include sorting, volume reduction, and packaging of dry waste, and collecting, processing, solidification, and packaging of liquid waste. The Waste Treatment Building System is located on the surface within the protected area of the MGR. The Waste Treatment Building System helps maintain a suitable environment for the waste processing and protects the systems within the Waste Treatment Building (WTB) from most of the natural and induced environments. The WTB also confines contaminants and provides radiological protection to personnel. In addition to the waste processing operations, the Waste Treatment Building System provides space and layout for staging of packaged waste for shipment, industrial and radiological safety systems, control and monitoring of operations, safeguards and security systems, and fire protection, ventilation and utilities systems. The Waste Treatment Building System also provides the required space and layout for maintenance activities, tool storage, and administrative facilities. The Waste Treatment Building System integrates waste processing systems within its protective structure to support the throughput rates established for the MGR. The Waste Treatment Building System also provides shielding, layout, and other design features to help limit personnel radiation exposures to levels which are as low as is reasonably achievable (ALARA). The Waste Treatment Building System interfaces with the Site Generated Radiological Waste Handling System, and with other MGR systems that support the waste processing operations. The Waste Treatment Building System interfaces with the General Site Transportation System, Site Communications System, Site Water System, MGR Site Layout, Safeguards and Security System, Site Radiological Monitoring System, Site Electrical Power System, Site Compressed Air System, and Waste Treatment Building Ventilation System.

F. Habashi

2000-06-22

127

ITER shielding analysis  

SciTech Connect

Nuclear design studies were carried out to obtain essential data to aid in the design of the International Thermonuclear Experimental Reactor (ITER). The ITER blanket and shield system is being designed to handle 1.5{plus_minus}0.3 GW of fusion power and 3 MWa/m{sup 2} average neutron fluence. Analyses concentrated on two designs. The first blanket-shield design uses type 316 Stainless-Steel (316SS) as the structural material with water coolant. The second tritium breeding-blanket design uses liquid lithium as the breeding material and vandium alloy (V-5Cr-5Ti) for the structure. The stainless-steel blanket-shield consists of a beryllium coated copper first wall followed by alternating layers of stainless-steel and water. The breeding blanket uses V-5Cr-5Ti as the structural material, beryllium as a neutron multiplier, and liquid lithium as the tritium breeding material. Also, the first wall in this design is coated with beryllium. A layer of 120mm-thick tungsten-carbide is incorporated in the rear section of the breeding blanket to enhance its shielding characteristics. The second components of the shield for both designs are included in the vacuum vessel. Also, a layer of boron carbide and lead, nominally 50mm-thick, is attached to the outer surface of the vacuum vessel to reduce the heat load and activation in the toroidal field coils. The analysis of the divertor pumping duct suggests that the structure surrounding the duct will reduce the nuclear heating and radiation damage in the conductor regions of the TF coils adjacent to the duct opening to acceptable levels.

Santoro, R.T.; Gohar, Y.; Parker, R.R. [ITER Joint Central Team, Garching (Germany)] [and others

1994-12-31

128

Review Article RADIATION SHIELDING TECHNOLOGY  

E-print Network

Review Article RADIATION SHIELDING TECHNOLOGY J. Kenneth Shultis and Richard E. Faw* Abstract Physics Society INTRODUCTION THIS IS a review of the technology of shielding against the effects to the review. The first treats the evolution of radiation-shielding technology from the beginning of the 20th

Shultis, J. Kenneth

129

Shielding of substations against direct lightning strokes by shield wires  

SciTech Connect

A new analysis for shielding outdoor substations against direct lightning strokes by shield wires is proposed. The basic assumption of this proposed method is that any lightning stroke which penetrates the shields will cause damage. The second assumption is that a certain level of risk of failure must be accepted, such as one or two failures per 100 years. The proposed method, using electrogeometric model, was applied to design shield wires for two outdoor substations: (1) 161-kV/69-kV station, and (2) 500-kV/161-kV station. The results of the proposed method were also compared with the shielding data of two other substations.

Chowdhuri, P. (Tennessee Technological Univ., Cookeville, TN (United States))

1994-01-01

130

Investigation of shielding from cosmic radiation  

NASA Technical Reports Server (NTRS)

Shielding from cosmic radiation is investigated. Attenuation of high energy protons in shielding material is noted and accumulations of radiation doses due to nuclear interactions in the shielding are studied. Shielding of artificial earth satellites is described.

Dubkin, V. Y.; Kovalev, Y. Y.; Skvortsov, S. S.; Smirennyy, L. N.; Vikhrov, A. I.

1973-01-01

131

Roof Shield for Advance and Retreat Mining  

NASA Technical Reports Server (NTRS)

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).

Lewis, E. V.

1985-01-01

132

Radiation shielding for the Fermilab Vertical Cavity Test Facility  

SciTech Connect

The results of radiation shielding studies for the vertical test cryostat VTS1 at Fermilab performed with the codes FISHPACT and MARS15 are presented and discussed. The analysis is focused on operations with two RF cavities in the cryostat. The vertical cavity test facility (VCTF) for superconducting RF cavities in Industrial Building 1 at Fermilab has been in operation since 2007. The facility currently consists of a single vertical test cryostat VTS1. Radiation shielding for VTS1 was designed for operations with single 9-cell 1.3 GHz cavities, and the shielding calculations were performed using a simplified model of field emission as the radiation source. The operations are proposed to be extended in such a way that two RF cavities will be in VTS1 at a time, one above the other, with tests for each cavity performed sequentially. In such a case the radiation emitted during the tests from the lower cavity can, in part, bypass the initially designed shielding which can lead to a higher dose in the building. Space for additional shielding, either internal or external to VTS1, is limited. Therefore, a re-evaluation of the radiation shielding was performed. An essential part of the present analysis is in using realistic models for cavity geometry and spatial, angular and energy distributions of field-emitted electrons inside the cavities. The calculations were performed with the computer codes FISHPACT and MARS15.

Ginsburg, Camille; Rakhno, Igor; /Fermilab

2010-03-01

133

Effects of various radiation source characteristics on shielding requirements at the potential Yucca Mountain repository  

SciTech Connect

This radiation shielding study provides dose rate information that can be used to estimate required shielding thicknesses for different repository configurations, including various hot cells and vaults in the waste-handling building, the boreholes in the underground emplacement area, and the transfer casks. The study determines gamma and neutron source strengths for various waste types and source geometries representative of conditions at the repository and determines dose rates as a function of shielding thickness for selected materials.

Smith, D.W.; Miller, D.D. [Bechtel National, Inc., San Francisco, CA (United States); Hill, R.R. [Sandia National Labs., Albuquerque, NM (United States)

1992-02-01

134

Composition for radiation shielding  

DOEpatents

A composition for use as a radiation shield is disclosed. The shield has a depleted uranium core for absorbing gamma rays and a bismuth coating for preventing chemical corrosion and absorbing gamma rays. Alternatively, a sheet of gadolinium may be positioned between the uranium core and the bismuth coating for absorbing neutrons. The composition is preferably in the form of a container for storing materials that emit radiation such as gamma rays and neutrons. The container is preferably formed by casting bismuth around a pre-formed uranium container having a gadolinium sheeting, and allowing the bismuth to cool. The resulting container is a structurally sound, corrosion-resistant, radiation-absorbing container. 2 figs.

Kronberg, J.W.

1994-08-02

135

Gas shielding apparatus  

DOEpatents

An apparatus is disclosed for preventing oxidation by uniformly distributing inert shielding gas over the weld area of workpieces such as pipes being welded together. The apparatus comprises a chamber and a gas introduction element. The chamber has an annular top wall, an annular bottom wall, an inner side wall and an outer side wall connecting the top and bottom walls. One side wall is a screen and the other has a portion defining an orifice. The gas introduction element has a portion which encloses the orifice and can be one or more pipes. The gas introduction element is in fluid communication with the chamber and introduces inert shielding gas into the chamber. The inert gas leaves the chamber through the screen side wall and is dispersed evenly over the weld area. 3 figs.

Brandt, D.

1985-12-31

136

Gas shielding apparatus  

DOEpatents

An apparatus for preventing oxidation by uniformly distributing inert shielding gas over the weld area of workpieces such as pipes being welded together. The apparatus comprises a chamber and a gas introduction element. The chamber has an annular top wall, an annular bottom wall, an inner side wall and an outer side wall connecting the top and bottom walls. One side wall is a screen and the other has a portion defining an orifice. The gas introduction element has a portion which encloses the orifice and can be one or more pipes. The gas introduction element is in fluid communication with the chamber and introduces inert shielding gas into the chamber. The inert gas leaves the chamber through the screen side wall and is dispersed evenly over the weld area.

Brandt, Daniel (Los Alamos, NM)

1985-01-01

137

Whipple bumper shield simulations  

SciTech Connect

The Whipple bumper is a space shield designed to protect a space station from the most hazardous orbital space debris environment. A series of numerical simulations has been performed using the multi-dimensional hydrodynamics code CTH to estimate the effectiveness of the thin Whipple bumper design. These simulations are performed for impact velocities of {approximately}10 km/s which are now accessible by experiments using the Sandia hypervelocity launcher facility. For a {approximately}10 km/s impact by a 0.7 gm aluminum flier plate, the experimental results indicate that the debris cloud resulting upon impact of the bumper shield by the flier plate, completely penetrates the sub-structure. The CTH simulations also predict complete penetration by the subsequent debris cloud. 5 refs., 4 figs., 2 tabs.

Hertel, E.S.; Chhabildas, L.C. (Sandia National Labs., Albuquerque, NM (USA)); Hill, S.A. (National Aeronautics and Space Administration, Huntsville, AL (USA). George C. Marshall Space Flight Center)

1991-01-01

138

Gas shielding apparatus  

DOEpatents

An apparatus for preventing oxidation by uniformly distributing inert shielding gas over the weld area of workpieces such as pipes being welded together. The apparatus comprises a chamber and a gas introduction element. The chamber has an annular top wall, an annular bottom wall, an inner side wall and an outer side wall connecting the top and bottom walls. One side wall is a screen and the other has a portion defining an orifice. The gas introduction element has a portion which encloses the orifice and can be one or more pipes. The gas introduction element is in fluid communication with the chamber and introduces inert shielding gas into the chamber. The inert gas leaves the chamber through the screen side wall and is dispersed evenly over the weld area.

Brandt, D.

1984-06-05

139

Magnetic shielding of the cold atom space clock PHARAO  

NASA Astrophysics Data System (ADS)

The space clock PHARAO is an atomic clock based on laser cooled cesium atoms. In order to attenuate magnetic field fluctuation in orbit, PHARAO clock uses three concentric Mumetal magnetic shields combined with several coils to improve the field homogeneity. We have characterized the attenuation and magnetic field homogeneity of the shields used to build the flight model. The average value of attenuation inside the three shields is around 18,000 when the external field is similar to the orbit field (30 ?T) and the field homogeneity is lower than 10 nT. These values have not changed after vibrations and thermal tests for the space qualification. Permeability variation of the shields as a function of the intercepted flux has been analyzed.

Moric, Igor; Laurent, Philippe; Chatard, Philippe; de Graeve, Charles-Marie; Thomin, Stephane; Christophe, Vincent; Grosjean, Olivier

2014-09-01

140

Experimental Shielding Evaluation of the Radiation Protection Provided by Residential Structures  

NASA Astrophysics Data System (ADS)

The human health and environmental effects following a postulated accidental release of radioactive material to the environment has been a public and regulatory concern since the early development of nuclear technology and researched extensively to better understand the potential risks for accident mitigation and emergency planning purposes. The objective of this investigation is to research and develop the technical basis for contemporary building shielding factors for the U.S. housing stock. Building shielding factors quantify the protection a certain building-type provides from ionizing radiation. Much of the current data used to determine the quality of shielding around nuclear facilities and urban environments is based on simplistic point-kernel calculations for 1950's era suburbia and is no longer applicable to the densely populated urban environments seen today. To analyze a building's radiation shielding properties, the ideal approach would be to subject a variety of building-types to various radioactive materials and measure the radiation levels in and around the building. While this is not entirely practicable, this research uniquely analyzes the shielding effectiveness of a variety of likely U.S. residential buildings from a realistic source term in a laboratory setting. Results produced in the investigation provide a comparison between theory and experiment behind building shielding factor methodology by applying laboratory measurements to detailed computational models. These models are used to develop a series of validated building shielding factors for generic residential housing units using the computational code MCNP5. For these building shielding factors to be useful in radiologic consequence assessments and emergency response planning, two types of shielding factors have been developed for; (1) the shielding effectiveness of each structure within a semi-infinite cloud of radioactive material, and (2) the shielding effectiveness of each structure from contaminant deposition on the roof and surrounding surfaces. For example, results from this investigation estimate the building shielding factors from a semi-infinite plume between comparable two-story models with a basement constructed with either brick-and-mortar or vinyl siding composing the exterior wall weather and a typical single-wide manufactured home with vinyl siding to be 0.36, 0.65, and 0.82 respectively.

Dickson, Elijah D.

141

DARHT : integration of shielding design and analysis with facility design /  

SciTech Connect

The design of the interior portions of the Dual Axis Radiographic Hydrodynamic Test (DARHT) Facility incorporated shielding and controls from the beginning of the installation of the Accelerators. The purpose of the design and analysis was to demonstrate the adequacy of shielding or to determine the need for additional shielding or controls. Two classes of events were considered: (1) routine operation defined as the annual production of 10,000 2000-ns pulses of electrons at a nominal energy of 20 MeV, some of which are converted to the x-ray imaging beam consisting of four nominal 60-ns pulses over the 2000-ns time frame, and (2) accident case defined as up to 100 2000-ns pulses of electrons accidentally impinging on some metallic surface, thereby producing x rays. Several locations for both classes of events were considered inside and outside of the accelerator hall buildings. The analysis method consisted of the definition of a source term for each case studied and the definition of a model of the shielding and equipment present between the source and the dose areas. A minimal model of the fixed existing or proposed shielding and equipment structures was used for a first approximation. If the resulting dose from the first approximation was below the design goal (1 rem/yr for routine operations, 5 rem for accident cases), then no further investigations were performed. If the result of the first approximation was above our design goals, the model was refined to include existing or proposed shielding and equipment. In some cases existing shielding and equipment were adequate to meet our goals and in some cases additional shielding was added or administrative controls were imposed to protect the workers. It is expected that the radiation shielding design, exclusion area designations, and access control features, will result in low doses to personnel at the DARHT Facility.

Boudrie, R. L. (Richard L.); Brown, T. H. (Thomas H.); Gilmore, W. E. (Walter E.); Downing, J. N. (James N.), Jr.; Hack, Alan; McClure, D. A. (Donald A.); Nelson, C. A. (Christine A.); Wadlinger, E. Alan; Zumbro, M. V. (Martha V.)

2002-01-01

142

Justification for Shielded Receiver Tube Additional Lead Shielding  

SciTech Connect

In order to reduce high radiation dose rates encountered when core sampling some radioactive waste tanks the addition of 240 lbs. of lead shielding is being considered to the shielded receiver tube on core sample trucks No.1, No.3 and No.4. The lead shielding is 4 inch diameter x 1/2 inch thick half rounds that have been installed around the SR tube over its' full length. Using three unreleased but independently reviewed structural analyses HNF-6018 justifies the addition of the lead shielding.

BOGER, R.M.

2000-04-11

143

Underground barrier construction apparatus with soil-retaining shield  

Microsoft Academic Search

An apparatus is described for building a horizontal underground barrier by cutting through soil and depositing a slurry, preferably one which cures into a hardened material. The apparatus includes a digging means for cutting and removing soil to create a void under the surface of the ground, a shield means for maintaining the void, and injection means for inserting barrier-forming

B. M. Gardner; A. M. Smith; R. W. Hanson; R. T. Hodges

1998-01-01

144

Underground barrier construction apparatus with soil-retaining shield  

Microsoft Academic Search

An apparatus for building a horizontal underground barrier by cutting through soil and depositing a slurry, preferably one which cures into a hardened material. The apparatus includes a digging means for cutting and removing soil to create a void under the surface of the ground, a shield means for maintaining the void, and injection means for inserting barrier-forming material into

Bradley M. Gardner; Ann Marie Smith; Richard W. Hanson; Richard T. Hodges

1998-01-01

145

Balloonlike Shields Against Fast Projectiles  

NASA Technical Reports Server (NTRS)

Report proposes use of flexible gas-filled or liquid-filled pouches to shield spacecraft against impacts by small meteoroids and orbiting debris traveling at speeds approximately greater than 2 km/s. Shields made in various forms reminiscent of balloons, pillows, air mattresses, or sealed-air-bubble packing material. Serve as lightweight, easily installed alternatives to heavier, rigid shields made of space aluminum sheets custom-designed and attached to spacecraft only with great difficulty and expense.

Rucker, Michelle A.

1993-01-01

146

Actively driven thermal radiation shield  

DOEpatents

A thermal radiation shield for cooled portable gamma-ray spectrometers. The thermal radiation shield is located intermediate the vacuum enclosure and detector enclosure, is actively driven, and is useful in reducing the heat load to mechanical cooler and additionally extends the lifetime of the mechanical cooler. The thermal shield is electrically-powered and is particularly useful for portable solid-state gamma-ray detectors or spectrometers that dramatically reduces the cooling power requirements. For example, the operating shield at 260K (40K below room temperature) will decrease the thermal radiation load to the detector by 50%, which makes possible portable battery operation for a mechanically cooled Ge spectrometer.

Madden, Norman W. (Livermore, CA); Cork, Christopher P. (Pleasant Hill, CA); Becker, John A. (Alameda, CA); Knapp, David A. (Livermore, CA)

2002-01-01

147

A magnetic shield/dual purpose mission  

NASA Technical Reports Server (NTRS)

The objective of this work is to design, build, and fly a dual-purpose payload whose function is to produce a large volume, low intensity magnetic field and to test the concept of using such a magnetic field to protect manned spacecraft against particle radiation. An additional mission objective is to study the effect of this moving field on upper atmosphere plasmas. Both mission objectives appear to be capable of being tested using the same superconducting coil. The potential benefits of this magnetic shield concept apply directly to both earth-orbital and interplanetary missions. This payload would be a first step in assessing the true potential of large volume magnetic fields in the U.S. space program. Either converted launch systems or piggyback payload opportunities may be appropriate for this mission. The use of superconducting coils for magnetic shielding against solar flare radiation during manned interplanetary missions has long been contemplated and was considered in detail in the years preceding the Apollo mission. With the advent of new superconductors, it has now become realistic to reconsider this concept for a Mars mission. Even in near-earth orbits, large volume magnetic fields produced using conventional metallic superconductors allow novel plasma physics experiments to be contemplated. Both deployed field-coil and non-deployed field-coil shielding arrangements have been investigated, with the latter being most suitable for an initial test payload in a polar orbit.

Watkins, Seth; Albertelli, Jamil; Copeland, R. Braden; Correll, Eric; Dales, Chris; Davis, Dana; Davis, Nechole; Duck, Rob; Feaster, Sandi; Grant, Patrick

1994-01-01

148

Hypervelocity impact shield  

NASA Technical Reports Server (NTRS)

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.

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

1991-01-01

149

Shielded enclosures for experimental studies of shielding topology  

Microsoft Academic Search

The report discusses the effort to provide shielded enclosures for EMP experimental studies of shielding topology. Section 1 discusses the theoretical modeling for which scattering matrices of subshields and their norms are used to relate the internal signals to the electromagnetic source environment. Both the line and aperture penetrations are included in the scattering matrix formulation. Experimental and analytical methods

F. C. Yang; K. S. H. Lee; S. A. Kokorowski; C. E. Baum; J. Hamm; W. Graf; E. F. Vance

1984-01-01

150

Enhanced meteoroid and orbital debris shielding  

Microsoft Academic Search

An innovative, low-weight shield system has been developed by NASA Johnson Space Center (JSC) and Marshall Space Flight Center (MSFC) engineers to enhance the protection of conventional Whipple shields. This shield, the “Stuffed Whipple” shield, includes a flexible blanket combining Nextel™ ceramic fabric and Kevlar™ fabric (or “stuffing”) between the aluminum bumper and rear wall of a Whipple shield. The

E. L. Christiansen; J. L. Crews; J. E. Williamsen; J. H. Robinson; A. M. Nolen

1995-01-01

151

Topographic evidence for shield volcanism on Io  

SciTech Connect

Similarities between terrestrial shield volcanoes and a volcano on Io observed in Voyager I imagery of the satellite at 30/sup 0/ S, 246/sup 0/ W are delineated. A photoclinometry model was used to numerically estimate the slope based on the Minnaert photometric function. The slope values are accurate to within 10 deg on the sun-facing slope and 1 deg on the shadow side. As found with shield volcanoes, the feature has a central edifice, 40-50 km in diameter, and a broad, elliptical base, 77 x 90 km across. The summit of the Io volcano is 2.2-2.8 km above the surrounding plane and contains a caldera about 5 km in diameter. The similarity in shape between basaltic terrestrial shield volcanoes and the Io volcano indicates that the Io feature may also be composed of basalt. The composition could be sulfur if the heat flow was under 0.05 W/sq m, as it might have been in later stages of formation. 9 references.

Moore, J.M.; Mcewen, A.S.; Albin, E.F.; Greeley, R.

1986-07-01

152

Numerical study on crack problems in segments of shield tunnel using finite element method  

Microsoft Academic Search

Crack problems of segments of shield tunnel are analyzed under the conditions of construction stage and service stage. 3D finite element method was adapted to establish elaborate numerical models of segments. For crack problems in construction stage, two models were used to analyze the following contents: (1) crack states of segments under jacking forces; (2) crack states of segments when

J. S. Chen; H. H. Mo

2009-01-01

153

Radiation Shielding Optimization on Mars  

NASA Technical Reports Server (NTRS)

Future space missions to Mars will require radiation shielding to be optimized for deep space transit and an extended stay on the surface. In deep space, increased shielding levels and material optimization will reduce the exposure from most solar particle events (SPE) but are less effective at shielding against galactic cosmic rays (GCR). On the surface, the shielding provided by the Martian atmosphere greatly reduces the exposure from most SPE, and long-term GCR exposure is a primary concern. Previous work has shown that in deep space, additional shielding of common materials such as aluminum or polyethylene does not significantly reduce the GCR exposure. In this work, it is shown that on the Martian surface, almost any amount of aluminum shielding increases exposure levels for humans. The increased exposure levels are attributed to neutron production in the shield and Martian regolith as well as the electromagnetic cascade induced in the Martian atmosphere. This result is significant for optimization of vehicle and shield designs intended for the surface of Mars.

Slaba, Tony C.; Mertens, Chris J.; Blattnig, Steve R.

2013-01-01

154

Evolution of the Hawaiian Mantle Plume: Shield and Rejuvenescent Magmatism at Middle Bank, the Youngest Sunken Hawaiian Volcano  

NASA Astrophysics Data System (ADS)

Post-shield volcanism provides unique insight into the structure of mantle plumes and the magmatic processes responsible for the evolution of ocean islands. Middle Bank is the closest seamount to the main Hawaiian archipelago, thus providing a perspective into the processes related to the dying phase of a Hawaiian volcano. We conducted a detailed survey of the volcano in 2007 using multibeam sonar coupled with Jason2 ROV imaging and sampling. According to plate tectonic models, Middle Bank volcano should be about 9.6 Ma, if it formed near the present location of Kilauea. Middle Bank is 100 km in diameter and rises nearly 5000 m from base level. Its morphology is dominated by three major rift zones that emanate to the east, west, and south from the beveled summit platform. The rifts are separated by talus fans, and the volcano is surrounded by dozens of satellite cones. Many of the satellite cones are covered by remarkably unsedimented lavas that were erupted in the submarine environment, which we interpret as a rejuvenated stage of volcanism. Most of the sampled rocks are strongly alkaline and range from basanite to hawaiite and trachyte. Samples from two sites are tholeiitic, which is consistent with them forming during the shield stage of volcanism. If so, then most of the late history of volcanism, from shield building to rejuvenated volcanism is preserved at Middle Bank. The alkaline basalts and basanites have La/Sm and La/Yb ratios that are higher than the tholeiites, and all of the rocks are strongly LREE enriched. Major and trace element compositions of hawaiites and trachytes are consistent with large amounts of crystal fractionation, which especially affected magmas erupted on the outer flanks of the volcano. The tholeiites have Sr/Nb and Zr/Nb that suggest that the Middle Bank shield is akin to the modern-day "Kea" trend geochemically. Thus, Middle Bank has preserved the archetypical tholeiitic-shield to alkaline-rejuvenated evolutionary stages that characterize the subaerial Hawaiian volcanoes.

Geist, D.; Garcia, M.; Ito, G.; Harpp, K.; Weis, D.

2008-12-01

155

Welding shield for coupling heaters  

DOEpatents

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.

Menotti, James Louis (Dickinson, TX)

2010-03-09

156

Portable convertible blast effects shield  

DOEpatents

A rapidly deployable portable convertible blast effects shield/ballistic shield includes a set two or more frusto-conically-tapered telescoping rings operably connected to each other to convert between a telescopically-collapsed configuration for storage and transport, and a telescopically-extended upright configuration forming an expanded inner volume. In a first embodiment, the upright configuration provides blast effects shielding, such as against blast pressures, shrapnel, and/or fire balls. And in a second embodiment, the upright configuration provides ballistic shielding, such as against incoming weapons fire, shrapnel, etc. Each ring has a high-strength material construction, such as a composite fiber and matrix material, capable of substantially inhibiting blast effects and impinging projectiles from passing through the shield. And the set of rings are releasably securable to each other in the telescopically-extended upright configuration by the friction fit of adjacent pairs of frusto-conically-tapered rings to each other.

Pastrnak, John W. (Livermore, CA); Hollaway, Rocky (Modesto, CA); Henning, Carl D. (Livermore, CA); Deteresa, Steve (Livermore, CA); Grundler, Walter (Hayward, CA); Hagler, Lisle B. (Berkeley, CA); Kokko, Edwin (Dublin, CA); Switzer, Vernon A. (Livermore, CA)

2011-03-15

157

Portable convertible blast effects shield  

DOEpatents

A rapidly deployable portable convertible blast effects shield/ballistic shield includes a set two or more telescoping cylindrical rings operably connected to each other to convert between a telescopically-collapsed configuration for storage and transport, and a telescopically-extended upright configuration forming an expanded inner volume. In a first embodiment, the upright configuration provides blast effects shielding, such as against blast pressures, shrapnel, and/or fire balls. And in a second embodiment, the upright configuration provides ballistic shielding, such as against incoming weapons fire, shrapnel, etc. Each ring has a high-strength material construction, such as a composite fiber and matrix material, capable of substantially inhibiting blast effects and impinging projectiles from passing through the shield. And the set of rings are releasably securable to each other in the telescopically-extended upright configuration, such as by click locks.

Pastrnak, John W. (Livermore, CA); Hollaway, Rocky (Modesto, CA); Henning, Carl D. (Livermore, CA); Deteresa, Steve (Livermore, CA); Grundler, Walter (Hayward, CA); Hagler,; Lisle B. (Berkeley, CA); Kokko, Edwin (Dublin, CA); Switzer, Vernon A (Livermore, CA)

2010-10-26

158

Portable convertible blast effects shield  

DOEpatents

A rapidly deployable portable convertible blast effects shield/ballistic shield includes a set two or more telescoping cylindrical rings operably connected to each other to convert between a telescopically-collapsed configuration for storage and transport, and a telescopically-extended upright configuration forming an expanded inner volume. In a first embodiment, the upright configuration provides blast effects shielding, such as against blast pressures, shrapnel, and/or fire balls. And in a second embodiment, the upright configuration provides ballistic shielding, such as against incoming weapons fire, shrapnel, etc. Each ring has a high-strength material construction, such as a composite fiber and matrix material, capable of substantially inhibiting blast effects and impinging projectiles from passing through the shield. And the set of rings are releasably securable to each other in the telescopically-extended upright configuration, such as by click locks.

Pastrnak, John W. (Livermore, CA); Hollaway, Rocky (Modesto, CA); Henning, Carl D. (Livermore, CA); Deteresa, Steve (Livermore, CA); Grundler, Walter (Hayward, CA); Hagler, Lisle B. (Berkeley, CA); Kokko, Edwin (Dublin, CA); Switzer, Vernon A (Livermore, CA)

2007-05-22

159

EBT-P gamma ray shielding analysis  

Microsoft Academic Search

First, a one-dimensional scoping study was performed for the gamma ray shield of the ELMO Bumpy Torus proof-of-principle device to define appropriate shielding material and determine the required shielding thickness. The dose equivalent results are analyzed as a function of the radiation shield thickness for different shielding options. A sensitivity analysis for the pessimistic case is given. The recommended shielding

Gohar

1983-01-01

160

Preliminary design of magnetic shielding by FEM  

SciTech Connect

In this paper, the authors propose an optimization method for magnetic shielding. The main purpose is the weight reduction of shield material. Assuming that the permeability of shield material is infinite, they simplify the magnetic shielding problem. Under this assumption, they design optimal passage for magnetic flux through the shield. They apply this method to designing the magnetic shielding for Maglev and show the effectiveness of this method by experimental and numerical data.

Sasakawa, Takashi; Tagawa, Naoto; Herai, Toshiki; Tomita, Masaru [Railway Technical Research Inst., Kokubunji, Tokyo (Japan)] [Railway Technical Research Inst., Kokubunji, Tokyo (Japan)

1997-03-01

161

Static Aerodynamic Performance Investigation of a Fluid Shield Nozzle  

NASA Technical Reports Server (NTRS)

In pursuit of an acoustically acceptable, high performance exhaust system capable of meeting Federal Aviation Regulation 36 Stage 3 noise goals for the High Speed Civil Transport application, General Electric Aircraft Engines conducted a design study to incorporate a fluid shield into a 36-chute suppressor exhaust-nozzle system. After a full scale preliminary mechanical design of the resulting fluid shield exhaust system, scale model aerodynamic performance tests and acoustic tests were conducted to establish both aerodynamic performance and acoustic characteristics. Data are presented as thrust coefficients, discharge coefficients, chute-base pressure drags, and plug static pressure distributions.

Balan, C.; Askew, J. W.

2005-01-01

162

Refractory shield for superheater tubes  

SciTech Connect

A refractory shield is described for protecting superheater tubes against attack by the products of combustion comprising: a pair of elongated molded and fired refractory half shields of predetermined identical interchangeable interlocking size and shape adapted when one of the half shields is rotated 180/sup 0/ and extends longitudinally relative to the other half shields to be slid axially together and interlocked together solely without additional fastening means, surround and shield the superheater tube. Each half shield has: an elongated refractory sidewall portion of predetermined axial length and thickness between opposite ends extending circumferentially between and to diametrically opposite refractory tongue and grooved side wall portions of predetermined axially engageable interlocking shape. An elongated tongue of predetermined shape, width and radial length projects radially outwardly from the tongue sidewall portion; and an elongated internal groove projects radially outward in the grooved side wall portion and of predetermined interlocking shape. Sufficient width and radial depth accept an elongated tongue of the other one of the pair of half shields assembled and locked together against relative rotation solely by axially inserting the tongues into the grooves.

Green, K.E.; Johnson, D.K.; Woodruff, R.W.

1987-07-28

163

New Materials for EMI Shielding  

NASA Technical Reports Server (NTRS)

Graphite fibers intercalated with bromine or similar mixed halogen compounds have substantially lower resistivity than their pristine counterparts, and thus should exhibit higher shielding effectiveness against electromagnetic interference. The mechanical and thermal properties are nearly unaffected, and the shielding of high energy x-rays and gamma rays is substantially increased. Characterization of the resistivity of the composite materials is subtle, but it is clear that the composite resistivity is substantially lowered. Shielding effectiveness calculations utilizing a simple rule of mixtures model yields results that are consistent with available data on these materials.

Gaier, James R.

1999-01-01

164

Radiation Shielding Properties of Some Marbles in Turkey  

SciTech Connect

Especially after development of technology, radiation started to be used in a large fields such as medicine, industry and energy. Using radiation in those fields bring hazardous effect of radiation into humancell. Thus radiation protection becomes important in physics. Although there are three ways for radiation protection, shielding of the radiation is the most commonly used method. Natural Stones such as marble is used as construction material especially in critical building and thus its radiation shielding capability should be determined.In this study, gamma ray shielding properties of some different types of marble mined in Turkey, have been measured using a NaI(Tl) scintillator detector. The measured results were also compared with the theoretical calculations XCOM.

Guenoglu, K.; Akkurt, I. [Sueleyman Demirel University, Faculty of Arts and Sciences, Dept. of Physics, Isparta (Turkey)

2011-12-26

165

Investigating Radiation Shielding Properties of Different Mineral Origin Heavyweight Concretes  

SciTech Connect

The radiation although has hazardous effects for human health, developing technologies bring lots of usage fields to radiation like in medicine and nuclear power station buildings. In this case protecting from undesirable radiation is a necessity for human health. Heavyweight concrete is one of the most important materials used in where radiation should be shielded, like those areas. In this study, used heavyweight aggregates of different mineral origin (Limonite, Siderite), in order to prepare different series in concrete mixtures and investigated radiation shielding properties. The experimental results on measuring the radiation shielding, the heavyweight concrete prepared with heavyweight aggregates of different mineral origin show that, are useful radiation absorbents when they used in concrete mixtures.

Basyigit, Celalettin; Uysal, Volkan; Kilincarslan, Semsettin; Akkas, Ayse [Department of Construction Education, Technical Education Faculty, Suleyman Demirel University, Isparta (Turkey); Mavi, Betuel [Department of Physics, Science Faculty, Suleyman Demirel University, Isparta (Turkey); Department of Physics, Science Faculty, Amasya University, Amasya (Turkey); Guenoglu, Kadir; Akkurt, Iskender [Department of Physics, Science Faculty, Suleyman Demirel University, Isparta (Turkey)

2011-12-26

166

Modified shielding jet model for twin-jet shielding analysis  

E-print Network

of the incident sound waves. Equivalently, these three factors may be summarized in terms of the barrier effectiveness and defined in the following way. The function of a barrier is to provide a "shadow zone", or reduced noise region, on the side of the jet... contributes to increased shielding at the higher frequencies on the shadow side of the jet. 3). Temperature Effects The hot jet presents a significant temperature gradient between the shielding jet and the surrounding medium. There is also considerable...

Gilbride, Jennifer Frances

1983-01-01

167

Approaches to building single-stage AC/AC conversion switch-mode audio power Petar Ljusev and Michael A.E. Andersen  

E-print Network

with a certain polarity across the combination of a filter and a loudspeaker, as decided by the control algorithm of the mains power into acoustic output in one simplified topological stage, like in the active loudspeaker

168

Structural/Radiation-Shielding Epoxies  

NASA Technical Reports Server (NTRS)

A development effort was directed toward formulating epoxy resins that are useful both as structural materials and as shielding against heavy-ion radiation. Hydrogen is recognized as the best element for absorbing heavy-ion radiation, and high-hydrogen-content polymers are now in use as shielding materials. However, high-hydrogen-content polymers (e.g. polyethylene) are typically not good structural materials. In contrast, aromatic polymers, which contain smaller amounts of hydrogen, often have the strength necessary for structural materials. Accordingly, the present development effort is based on the concept that an ideal structural/ heavy-ion-radiation-shielding material would be a polymer that contains sufficient hydrogen (e.g., in the form of aliphatic molecular groups) for radiation shielding and has sufficient aromatic content for structural integrity.

Connell, John W.; Smith, Joseph G.; Hinkley, Jeffrey; Blattnig, Steve; Delozier, Donavon M.; Watson, Kent A.; Ghose, Sayata

2009-01-01

169

Heat-Shield Gap Filler  

NASA Technical Reports Server (NTRS)

Ceramic cloth strips provide flexible, easily replaceable insulating filler. Filler prevents hot gas from flowing between heat-shield tiles while allowing space for thermal expansion and contraction. Strips easily replaced when necessary.

Leiser, D. B.; Stewart, D. A.; Smith, M.; Estrella, C.; Goldstein, H. E.

1985-01-01

170

Radiation Shielding and Radiological Protection  

E-print Network

Radiation Shielding and Radiological Protection J. Kenneth Shultis Richard E. Faw Department@triad.rr.com Radiation Fields and Sources ................................................ . Radiation Field Variables........................................................... .. Direction and Solid Angle Conventions ......................................... .. Radiation Fluence

Shultis, J. Kenneth

171

Composite Aerogel Multifoil Protective Shielding  

NASA Technical Reports Server (NTRS)

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.

Jones, Steven M.

2013-01-01

172

Magnetic Shield for Adiabatic Demagnetization Refrigerators (ADR)  

NASA Technical Reports Server (NTRS)

A new method was developed for creating a less expensive shield for ADRs using 1018 carbon steel. This shield has been designed to have similar performance to the expensive vanadium permendur shields, but the cost is 30 to 50% less. Also, these shields can be stocked in a variety of sizes, eliminating the need for special forgings, which also greatly reduces cost.

Chui, Talso C.; Haddad, Nicolas E.

2013-01-01

173

Transient heat flux shielding using thermal metamaterials  

NASA Astrophysics Data System (ADS)

We have developed a heat shield based on a metamaterial engineering approach to shield a region from transient diffusive heat flow. The shield is designed with a multilayered structure to prescribe the appropriate spatial profile for heat capacity, density, and thermal conductivity of the effective medium. The heat shield was experimentally compared to other isotropic materials.

Narayana, Supradeep; Savo, Salvatore; Sato, Yuki

2013-05-01

174

Integral Face Shield Concept for Firefighter's Helmet  

NASA Technical Reports Server (NTRS)

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.

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

1982-01-01

175

Thermal neutron shield and method of manufacture  

DOEpatents

A thermal neutron shield comprising boron shielding panels with a high percentage of the element Boron. The panel is least 46% Boron by weight which maximizes the effectiveness of the shielding against thermal neutrons. The accompanying method discloses the manufacture of boron shielding panels which includes enriching the pre-cursor mixture with varying grit sizes of Boron Carbide.

Metzger, Bert Clayton; Brindza, Paul Daniel

2014-03-04

176

Shielding Strategies for Human Space Exploration  

Microsoft Academic Search

The shield effectiveness of lunar regolith is compared with possible prefabricated shield materials from Earth,including commercially used shield materials in nuclear facilities. Several of the fabricated materials categorized asneutron absorbers and moderators exhibit favorable characteristics for space radiation protection. Although thiseffort is not intended to be a definitive trade study for specific shielding recommendations, attention is given toseveral factors that

J. W. Wilson; J. Miller; A. Konradi; F. A. Cucinotta

1997-01-01

177

Transient heat flux shielding using thermal metamaterials  

E-print Network

We have developed a heat shield based on a metamaterial engineering approach to shield a region from transient diffusive heat flow. The shield is designed with a multilayered structure to prescribe the appropriate spatial profile for heat capacity, density, and thermal conductivity of the effective medium. The heat shield was experimentally compared to other isotropic materials.

Narayana, Supradeep; Sato, Yuki

2013-01-01

178

Magnetic shielding for interplanetary spacecraft  

SciTech Connect

The protection of spacecraft crews from the radiation produced by high energy electrons, protons and heavier ions in the space environment is a major health concern on long duration missions. Conventional approaches to radiation shielding in space have relied on thicker spacecraft walls to stop the high energy charged particles and to absorb the resulting gamma and bremsstrahlung photons. The shielding concept described here uses superconducting magnets to deflect charged particles before they collide with the spacecraft, thus avoiding the production of secondary particles. A number of spacecraft configurations and sizes have been analyzed, ranging from a small ``storm cellar`` for use during solar flares to continuous shielding for space stations having a crew of 15--25. The effectiveness of the magnetic shielding has been analyzed using a Monte Carlo program with incident proton energies from 0.5 to 1000 MeV. Typically the shield deflects 35--99 percent of the incident particles, depending, of course on particle energy and magnetic field strength. Further evaluation studies have been performed to assess weight comparisons between magnetic and conventional shielding; to determine magnet current distributions which minimize the magnetic field within the spacecraft itself; and to assess the potential role of ceramic superconductors. 2 figs., 8 tabs.

Herring, J.S.; Merrill, B.J.

1991-12-01

179

Magnetic shielding for interplanetary spacecraft  

SciTech Connect

The protection of spacecraft crews from the radiation produced by high energy electrons, protons and heavier ions in the space environment is a major health concern on long duration missions. Conventional approaches to radiation shielding in space have relied on thicker spacecraft walls to stop the high energy charged particles and to absorb the resulting gamma and bremsstrahlung photons. The shielding concept described here uses superconducting magnets to deflect charged particles before they collide with the spacecraft, thus avoiding the production of secondary particles. A number of spacecraft configurations and sizes have been analyzed, ranging from a small storm cellar'' for use during solar flares to continuous shielding for space stations having a crew of 15--25. The effectiveness of the magnetic shielding has been analyzed using a Monte Carlo program with incident proton energies from 0.5 to 1000 MeV. Typically the shield deflects 35--99 percent of the incident particles, depending, of course on particle energy and magnetic field strength. Further evaluation studies have been performed to assess weight comparisons between magnetic and conventional shielding; to determine magnet current distributions which minimize the magnetic field within the spacecraft itself; and to assess the potential role of ceramic superconductors. 2 figs., 8 tabs.

Herring, J.S.; Merrill, B.J.

1991-01-01

180

Shielding requirements in helical tomotherapy.  

PubMed

Helical tomotherapy is a relatively new intensity-modulated radiation therapy (IMRT) treatment for which room shielding has to be reassessed for the following reasons. The beam-on-time needed to deliver a given target dose is increased and leads to a weekly workload of typically one order of magnitude higher than that for conventional radiation therapy. The special configuration of tomotherapy units does not allow the use of standard shielding calculation methods. A conventional linear accelerator must be shielded for primary, leakage and scatter photon radiations. For tomotherapy, primary radiation is no longer the main shielding issue since a beam stop is mounted on the gantry directly opposite the source. On the other hand, due to the longer irradiation time, the accelerator head leakage becomes a major concern. An analytical model based on geometric considerations has been developed to determine leakage radiation levels throughout the room for continuous gantry rotation. Compared to leakage radiation, scatter radiation is a minor contribution. Since tomotherapy units operate at a nominal energy of 6 MV, neutron production is negligible. This work proposes a synthetic and conservative model for calculating shielding requirements for the Hi-Art II TomoTherapy unit. Finally, the required concrete shielding thickness is given for different positions of interest. PMID:17671353

Baechler, S; Bochud, F O; Verellen, D; Moeckli, R

2007-08-21

181

Shielding requirements in helical tomotherapy  

NASA Astrophysics Data System (ADS)

Helical tomotherapy is a relatively new intensity-modulated radiation therapy (IMRT) treatment for which room shielding has to be reassessed for the following reasons. The beam-on-time needed to deliver a given target dose is increased and leads to a weekly workload of typically one order of magnitude higher than that for conventional radiation therapy. The special configuration of tomotherapy units does not allow the use of standard shielding calculation methods. A conventional linear accelerator must be shielded for primary, leakage and scatter photon radiations. For tomotherapy, primary radiation is no longer the main shielding issue since a beam stop is mounted on the gantry directly opposite the source. On the other hand, due to the longer irradiation time, the accelerator head leakage becomes a major concern. An analytical model based on geometric considerations has been developed to determine leakage radiation levels throughout the room for continuous gantry rotation. Compared to leakage radiation, scatter radiation is a minor contribution. Since tomotherapy units operate at a nominal energy of 6 MV, neutron production is negligible. This work proposes a synthetic and conservative model for calculating shielding requirements for the Hi-Art II TomoTherapy unit. Finally, the required concrete shielding thickness is given for different positions of interest.

Baechler, S.; Bochud, F. O.; Verellen, D.; Moeckli, R.

2007-08-01

182

Atlas SCT/Pixel Grounding and Shielding ATLAS SCT/Pixel Grounding and Shielding Note  

E-print Network

Atlas SCT/Pixel Grounding and Shielding 1 ATLAS SCT/Pixel Grounding and Shielding Note November 22 mostly connects existing mechanical electrical conductive #12; Atlas SCT/Pixel Grounding and Shielding 2 that equivalent. The barrel outer heat shield (150 aluminum) main element shield. #12; Atlas SCT/Pixel Grounding

California at Santa Cruz, University of

183

Jet Noise Shielding Provided by a Hybrid Wing Body Aircraft  

NASA Technical Reports Server (NTRS)

One approach toward achieving NASA's aggressive N+2 noise goal of 42 EPNdB cumulative margin below Stage 4 is through the use of novel vehicle configurations like the Hybrid Wing Body (HWB). Jet noise measurements from an HWB acoustic test in NASA Langley's 14- by 22-Foot Subsonic Tunnel are described. Two dual-stream, heated Compact Jet Engine Simulator (CJES) units are mounted underneath the inverted HWB model on a traversable support to permit measurement of varying levels of shielding provided by the fuselage. Both an axisymmetric and low noise chevron nozzle set are investigated in the context of shielding. The unshielded chevron nozzle set shows 1 to 2 dB of source noise reduction (relative to the unshielded axisymmetric nozzle set) with some penalties at higher frequencies. Shielding of the axisymmetric nozzles shows up to 6.5 dB of reduction at high frequency. The combination of shielding and low noise chevrons shows benefits beyond the expected additive benefits of the two, up to 10 dB, due to the effective migration of the jet source peak noise location upstream for increased shielding effectiveness. Jet noise source maps from phased array results processed with the Deconvolution Approach for the Mapping of Acoustic Sources (DAMAS) algorithm reinforce these observations.

Doty, Michael J.; Brooks, Thomas F.; Burley, Casey L.; Bahr, Christopher J.; Pope, Dennis S.

2014-01-01

184

Structural Design and Thermal Analysis for Thermal Shields of the MICE Coupling Magnets  

SciTech Connect

A superconducting coupling magnet made from copper matrix NbTi conductors operating at 4 K will be used in the Muon Ionization Cooling Experiment (MICE) to produce up to 2.6 T on the magnet centerline to keep the muon beam within the thin RF cavity indows. The coupling magnet is to be cooled by two cryocoolers with a total cooling capacity of 3 W at 4.2 K. In order to keep a certain operating temperature margin, the most important is to reduce the heat leakage imposed on cold surfaces of coil cold mass assembly. An ntermediate temperature shield system placed between the coupling coil and warm vacuum chamber is adopted. The shield system consists of upper neck shield, main shields, flexible connections and eight supports, which is to be cooled by the first stage cold heads of two ryocoolers with cooling capacity of 55 W at 60 K each. The maximum temperature difference on the shields should be less than 20 K, so the thermal analyses for the shields with different thicknesses, materials, flexible connections for shields' cooling and structure design for heir supports were carried out. 1100 Al is finally adopted and the maximum temperature difference is around 15 K with 4 mm shield thickness. The paper is to present detailed analyses on the shield system design.

Green, Michael A.; Pan, Heng; Liu, X. K.; Wang, Li; Wu, Hong; Chen, A. B.; Guo, X.L.

2009-07-01

185

Staging Airliner Service  

NASA Technical Reports Server (NTRS)

There is a general consensus building that historically high fuel prices and greater public awareness of the emissions that result from burning fuel are going to be long-term concerns for those who design, build, and operate airliners. The possibility of saving both fuel and reducing emissions has rekindled interest in breaking very long-range airline flights into multiple stages or even adopting in-flight refueling. It is likely that staging will result in lower fuel burn, and recent published reports have suggested that the savings are substantial, particularly if the airliner is designed from the outset for this kind of operation. Given that staging runs against the design and operation historical trend, this result begs for further attention. This paper will examine the staging question, examining both analytic and numeric performance estimation methodologies to quantify the likely amount of fuel savings that can be expected and the resulting design impacts on the airliner.

Hahn, Andrew S.

2007-01-01

186

Electrodynamic Dust Shield Demonstrator  

NASA Technical Reports Server (NTRS)

The objective of the project was to design and manufacture a device to demonstrate a new technology developed by NASA's Electrostatics and Surface Physics Laboratory. The technology itself is a system which uses magnetic principles to remove regolith dust from its surface. This project was to create an enclosure that will be used to demonstrate the effectiveness of the invention to The Office of the Chief Technologist. ONE of the most important challenges of space exploration is actually caused by something very small and seemingly insignificant. Dust in space, most notably on the moon and Mars, has caused many unforeseen issues. Dirt and dust on Earth, while a nuisance, can be easily cleaned and kept at bay. However, there is considerably less weathering and erosion in space. As a result, the microscopic particles are extremely rough and abrasive. They are also electrostatically charged, so they cling to everything they make contact with. This was first noted to be a major problem during the Apollo missions. Dust would stick to the spacesuits, and could not be wiped off as predicted. Dust was brought back into the spacecraft, and was even inhaled by astronauts. This is a major health hazard. Atmospheric storms and other events can also cause dust to coat surfaces of spacecraft. This can cause abrasive damage to the craft. The coating can also reduce the effectiveness of thermal insulation and solar panels.' A group of engineers at Kennedy Space Center's Electrostatics and Surface Physics Laboratory have developed a new technology, called the Electrodynamic Dust Shield, to help alleviate these problems. It is based off of the electric curtain concept developed at NASA in 1967. "The EDS is an active dust mitigation technology that uses traveling electric fields to transport electrostatically charged dust particles along surfaces. To generate the traveling electric fields, the EDS consists of a multilayer dielectric coating with an embedded thin electrode grid running a multiphase low frequency AC signal. Electrostatically charged particles, such as those encountered on the moon, Mars, or an asteroid, are carried along by the traveling field due to the action of Coulomb and dielectrophoretic forces."2 The technical details have been described in a separate article. This document details the design and construction process of a small demonstration unit. Once finished, this device will go to the Office of the ChiefTechnologist at NASA headquarters, where it will be used to familiarize the public with the technology. 1 NASA KSC FO Intern, Prototype Development Laboratory, Kennedy Space Center, University of Central Florida Kennedy Space

Stankie, Charles G.

2013-01-01

187

Theoretical and experimental evaluation of the electromagnetic radiation from apertures in shielded enclosure  

Microsoft Academic Search

The problem of the radiated emission from apertures in metallic enclosures has been theoretically and experimentally investigated. In particular, the tangential electric field in the aperture has been evaluated by two methods: the first is helpful during the design stage and the second during the prototype development stage of electronic equipment shielded by a metallic box. The first method is

Graziano Cerri; Roberto De Leo; V. M. Primiani

1992-01-01

188

Radiation shielding materials and containers incorporating same  

DOEpatents

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.

Mirsky, Steven M. (Greenbelt, MD); Krill, Stephen J. (Arlington, VA); Murray, Alexander P. (Gaithersburg, MD)

2005-11-01

189

Radiation Shielding Materials and Containers Incorporating Same  

DOEpatents

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.

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

2005-11-01

190

Trailer shield assembly for a welding torch  

NASA Technical Reports Server (NTRS)

This invention relates generally to trailer shields for gas shielded arc welding torches, and more particularly to a trailer shield assembly provided with a shield gas manifold for providing an even dispersion of shield gas to the interior of the shield assembly, which generally encloses a joint being welded and a welding trailing portion of hot welded metal. The novelty of the invention lies in providing trailer shield with a manifold tube having a plurality of openings from which shield gas is distributed. A gas manifold region ahead of the torch is also provided with shield gas from a tube to protect metal preheated by the torch. Further novelty lies in constructing portions of sides and housing and portions of side walls of the guide of stainless steel screen having a tight mesh.

Dyer, Gerald E. (inventor)

1989-01-01

191

Jet shielding of jet noise  

NASA Technical Reports Server (NTRS)

An experimental and theoretical study was conducted to develop a validated first principle analysis for predicting the jet noise reduction achieved by shielding one jet exhaust flow with a second, closely spaced, identical jet flow. A generalized fuel jet noise analytical model was formulated in which the acoustic radiation from a source jet propagates through the velocity and temperature discontinuity of the adjacent shielding jet. Input variables to the prediction procedure include jet Mach number, spacing, temperature, diameter, and source frequency. Refraction, diffraction, and reflection effects, which control the dual jet directivity pattern, are incorporated in the theory. The analysis calculates the difference in sound pressure level between the dual jet configuration and the radiation field based on superimposing two independent jet noise directivity patterns. Jet shielding was found experimentally to reduce noise levels in the common plane of the dual jet system relative to the noise generated by two independent jets.

Simonich, J. C.; Amiet, R. K.; Schlinker, R. H.

1986-01-01

192

Concepts and Tests for the Remote-Controlled Dismantling of the Biological Shield and Form work of the KNK Reactor - 13425  

SciTech Connect

The compact sodium-cooled nuclear reactor facility Karlsruhe (KNK), a prototype Fast Breeder, is currently in an advanced stage of dismantling. Complete dismantling is based on 10 partial licensing steps. In the frame of the 9. decommissioning permit, which is currently ongoing, the dismantling of the biological shield is foreseen. The biological shield consists of heavy reinforced concrete with built-in steel fitments, such as form-work of the reactor tank, pipe sleeves, ventilation channels, and measuring devices. Due to the activation of the inner part of the biological shield, dismantling has to be done remote-controlled. During a comprehensive basic design phase a practical dismantling strategy was developed. Necessary equipment and tools were defined. Preliminary tests revealed that hot wire plasma cutting is the most favorable cutting technology due to the geometrical boundary conditions, the varying distance between cutter and material, and the heavy concrete behind the steel form-work. The cutting devices will be operated remotely via a carrier system with an industrial manipulator. The carrier system has expandable claws to adjust to the varying diameter of the reactor shaft during dismantling progress. For design approval of this prototype development, interaction between manipulator and hot wire plasma cutting was tested in a real configuration. For the demolition of the concrete structure, an excavator with appropriate tools, such as a hydraulic hammer, was selected. Other mechanical cutting devices, such as a grinder or rope saw, were eliminated because of concrete containing steel spheres added to increase the shielding factor of the heavy concrete. Dismantling of the biological shield will be done in a ring-wise manner due to static reasons. During the demolition process, the excavator is positioned on its tripod in three concrete recesses made prior to the dismantling of the separate concrete rings. The excavator and the manipulator carrier system will be operated alternately. Main boundary condition for all the newly designed equipment is the decommissioning housing of limited space within the reactor building containment. To allow for a continuous removal of the concrete rubble, an additional opening on the lowest level of the reactor shaft will be made. All equipment and the interaction of the tools have to be tested before use in the controlled area. Therefore a full-scale model of the biological shield will be provided in a mock-up. The tests will be performed in early 2014. The dismantling of the biological shield is scheduled for 2015. (authors)

Neff, Sylvia; Graf, Anja; Petrick, Holger; Rothschmitt, Stefan [WAK Rueckbau- und Entsorgungs- GmbH, P.O.Box 12 63, 76339 Eggenstein- Leopoldshafen (Germany)] [WAK Rueckbau- und Entsorgungs- GmbH, P.O.Box 12 63, 76339 Eggenstein- Leopoldshafen (Germany); Klute, Stefan [Siempelkamp Nukleartechnik GmbH, Am Taubenfeld 25/1, 69123 Heidelberg (Germany)] [Siempelkamp Nukleartechnik GmbH, Am Taubenfeld 25/1, 69123 Heidelberg (Germany); Stanke, Dieter [Siempelkamp NIS Ingenieurgesellschaft mbH, Industriestrasse 13, 63755 Alzenau (Germany)] [Siempelkamp NIS Ingenieurgesellschaft mbH, Industriestrasse 13, 63755 Alzenau (Germany)

2013-07-01

193

D0 Silicon Upgrade: Muon Shield Conceptual Design Report  

SciTech Connect

The nominal overall dimensions are 71-inch high x 71-inch wide x 144-inch long and has a 25-inch square hole throughout. The shield consists of three different materials, steel (inner most section), polycarbonate (central section) and lead (outer most section). The material thicknesses are, steel=15-inch, poly=6-inch and lead=2-inch. The estimated weight is {approx}69 tons. The shield is centered about the Tev beam line and the 25-inch square hole provides clearance to the low Beta quad, which is nominally 20-inch square. During beamline operation, the shield is in contact with Samus magnet core at the detector end and with the Main Ring shield wall on the MR side (with some small clearance {approx}2-inch-3-inch). The need for the clearance will be discussed later. The shield support structure consists steel structural members appropriately sized for loads encountered in the design. The structure must not only support the shield but, must be designed for rolling the entire assembly into position in the collision hall. It must provide for cylinders to lift the assembly, Hilman rollers and also connections for moving the entire assembly. The movement is considered to be similar to that with which the calorimeters were moved from the clean room to the sidewalk staging area, i.e. hydraulic cylinder and chain (see dwg. 3740.000-ME294017,3 sheets). This method will be used for the East to West motion and a hydraulic scheme will be used for any North-South motion. Since the shield is 144-inch long and the sidewalk structural support is {approx}96-inch, there is a section of the shield that is cantilevered (48-inch). Further, the EF toroid must open {approx}40+ inch for access to the detector during operations and this requires that the shield or some part of it must also move. This conceptual design suggests that the shield be designed in two pieces axially. These two pieces are identical in cross section but, the lengths are divided into 48-inch nearest EF and 96-inch nearest the MR tunnel. The 96-inch section is designed to clam shell, i.e. split vertically along the beam line, with each half moving {approx}36-inch East/West. The opening created with this motion (72-inch) is 1-inch greater than the width of the shield, 71 If. Now the forward section can be moved, North/South, within the opened end section, a full 48-inch. The forward section will be support at one end by the basic shield support structure and at the EF end by a member welded to EF. Rails will be extended from the basic structure to EF and these rails will be collapsible within the basic structure. The shield sections will be mounted on Hilman rollers and all motions will be provided by hydraulic cylinders.

Stredde, Herman J.; /Fermilab

1996-05-14

194

Acoustic and Aero-Mixing Experimental Results for Fluid Shield Scale Model Nozzles  

NASA Technical Reports Server (NTRS)

The principle objectives of this investigation are to evaluate the acoustic and aerodynamic characteristics of fluid shield nozzle concept and to assess Far 36, Stage 3 potential for fluid shield nozzle with Flade Cycle. Acoustic data for nine scale model nozzle configurations are obtained. The effects of simulated flight and geometric and aerothermodynamic flow variables on the acoustic behavior of the fluid shield are determined. The acoustic tests are aimed at studying the effect of: (1) shield thickness, (2) wrap angle, (3) mass flow and velocity ratios between shield and core streams at constant cycle specific thrust (i.e., mixed velocity), (4) porous plug, and (5) subsonic shield. Shadowgraphs of six nozzle configurations are obtained to understand the plume flowfield features. Static pressure data on suppressor chutes in the core stream (shielded and unshielded) sides and on plug surface are acquired to determine the impact of fluid shield on base drag of the 36-chute suppressor nozzle and the thrust augmentation due to the plug, respectively.

Salikuddin, M.; Mengle, V. G.; Shin, H. W.; Majjigi, R. K.

2005-01-01

195

Accelerator shield design of KIPT neutron source facility  

SciTech Connect

Argonne National Laboratory (ANL) of the United States and Kharkov Institute of Physics and Technology (KIPT) of Ukraine have been collaborating on the design development of a neutron source facility at KIPT utilizing an electron-accelerator-driven subcritical assembly. Electron beam power is 100 kW, using 100 MeV electrons. The facility is designed to perform basic and applied nuclear research, produce medical isotopes, and train young nuclear specialists. The biological shield of the accelerator building is designed to reduce the biological dose to less than 0.5-mrem/hr during operation. The main source of the biological dose is the photons and the neutrons generated by interactions of leaked electrons from the electron gun and accelerator sections with the surrounding concrete and accelerator materials. The Monte Carlo code MCNPX serves as the calculation tool for the shield design, due to its capability to transport electrons, photons, and neutrons coupled problems. The direct photon dose can be tallied by MCNPX calculation, starting with the leaked electrons. However, it is difficult to accurately tally the neutron dose directly from the leaked electrons. The neutron yield per electron from the interactions with the surrounding components is less than 0.01 neutron per electron. This causes difficulties for Monte Carlo analyses and consumes tremendous computation time for tallying with acceptable statistics the neutron dose outside the shield boundary. To avoid these difficulties, the SOURCE and TALLYX user subroutines of MCNPX were developed for the study. The generated neutrons are banked, together with all related parameters, for a subsequent MCNPX calculation to obtain the neutron and secondary photon doses. The weight windows variance reduction technique is utilized for both neutron and photon dose calculations. Two shielding materials, i.e., heavy concrete and ordinary concrete, were considered for the shield design. The main goal is to maintain the total dose outside the shield boundary at less than 0.5-mrem/hr. The shield configuration and parameters of the accelerator building have been determined and are presented in this paper. (authors)

Zhong, Z.; Gohar, Y. [Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL 60439 (United States)

2013-07-01

196

Microscopic and early stage ovarian cancers in BRCA1/2 mutation carriers: building a model for early BRCA-associated tumorigenesis  

PubMed Central

Risk-reducing salpingo-oophorectomy (RRSO) is the cornerstone of ovarian cancer prevention in BRCA1/2 mutation carriers. Occult fallopian tube and ovarian cancers have been reported in a small percentage of BRCA1/2 mutation carriers undergoing RRSO. Here, we review our single institution experience with RRSO in BRCA1/2 mutation carriers to characterize cases of microscopic cancers in these patients. At the time of RRSO, 7.9% of BRCA1 mutation carriers were diagnosed with microscopic fallopian tube or ovarian cancers and zero cases were diagnosed in BRCA2 mutation carriers. The majority of the microscopic cancers include cases that were confined to the fallopian tubes, although there were also cases involving ovaries only or peritoneal washings only. This suggests that the site of origin may be in the ovary, fallopian tube, or peritoneum for BRCA-associated serous cancers. However, an analysis of early stage (stage I and II) ovarian and fallopian tube cancers diagnosed in BRCA1/2 mutation carriers confirms that the ovary is a preferred site for tumor growth with 11 of 14 early stage cancers having a dominant ovarian mass. Overall, these data suggest that cancer initiation may occur in the ovary, fallopian tube, or peritoneum, but tumor growth and progression is favored in the ovary. We present an updated model for BRCA1/2-associated ovarian and fallopian tube carcinogenesis, which may aid in identifying improved prevention strategies for high-risk women that delay or decline RRSO. PMID:21278312

Yates, Melinda S.; Meyer, Larissa A.; Deavers, Michael T.; Daniels, Molly S.; Keeler, Elizabeth R.; Mok, Samuel C.; Gershenson, David M.; Lu, Karen H.

2011-01-01

197

6500 Staticide ESD Safety Shield  

E-print Network

6500 Staticide® ESD Safety Shield Translucent Surface resistivity of 106 to 109 ohms it is a translucent coating, it is per- fect for spraying on viewing ports. This coating is safe to use. *initial laboratory tests have shown the coating to last in excess of 12 months ACL Inc. registered to ISO

Washington at Seattle, University of - Department of Physics, Electroweak Interaction Research Group

198

GAMMA RAY SHIELDING FOR ENGINEERS  

Microsoft Academic Search

Information is given on the types of particle encountered in nuclear ; energy plant, their interactions with matter, the calculation of their rates of ; emission, the acceptable amounts which may be absorbed by the plant operators, ; and the calculation of radiation level for various source-shield dispositions. ; (auth)

1954-01-01

199

Rotary stripper for shielded and unshielded FCC  

NASA Technical Reports Server (NTRS)

Rotary stripper removes narrow strips of insulation and shielding to any desired depth. Unshielded cables are stripped on both sides with one stroke, shielded cables are stripped in steps of different depths.

Angele, W.; Chambers, C. M.

1971-01-01

200

Reliability-Based Electronics Shielding Design Tools  

NASA Technical Reports Server (NTRS)

Shielding design on large human-rated systems allows minimization of radiation impact on electronic systems. Shielding design tools require adequate methods for evaluation of design layouts, guiding qualification testing, and adequate follow-up on final design evaluation.

Wilson, J. W.; O'Neill, P. J.; Zang, T. A.; Pandolf, J. E.; Tripathi, R. K.; Koontz, Steven L.; Boeder, P.; Reddell, B.; Pankop, C.

2007-01-01

201

Concerning superconducting inertial guidance gyroscopes inside superconducting magnetic shields  

SciTech Connect

Superconductors can in theory be used to detect rotation by Josephson interference or by detection of the London field, a magnetic induction that fills the interior of any rotating bulk superconductor. One might hope to use these properties of superconductors to build a practical inertial guidance gyroscope. A problem arises from the necessity of surrounding the device with superconducting magnetic shielding: the London field generated by a co-rotating shield eliminates the response of the superconducting device within the shield. The present article demonstrates this point more rigorously than has been done before, discussing solutions of Ampere`s law for rotating and nonrotating superconductors and paying careful attention to boundary conditions. Beginning with a supercurrent density derivable from either the Ginzburg-Landau or the London theory of superconductivity, the article shows: (1) that a superconducting device cannot distinguish between rotation and an applied magnetic field; (2) that a superconducting device surrounded by a co-rotating superconducting shield cannot detect rotation. The term `superconducting gyroscope` in this article refers only to a device whose working principle is the response of the superconductor itself to rotation, not to any device in which superconducting electronic components are used to detect some other effect. {copyright} {ital 1997 American Institute of Physics.}

Satterthwaite, J.C.; Gawlinski, E.T. [Department of Physics, Temple University, Philadelphia, Pennsylvania (United States)] [Department of Physics, Temple University, Philadelphia, Pennsylvania (United States)

1997-12-01

202

Predictions for Radiation Shielding Materials  

NASA Technical Reports Server (NTRS)

Radiation from galactic cosmic rays (GCR) and solar particle events (SPE) is a serious hazard to humans and electronic instruments during space travel, particularly on prolonged missions outside the Earth s magnetic fields. Galactic cosmic radiation (GCR) is composed of approx. 98% nucleons and approx. 2% electrons and positrons. Although cosmic ray heavy ions are 1-2% of the fluence, these energetic heavy nuclei (HZE) contribute 50% of the long-term dose. These unusually high specific ionizations pose a significant health hazard acting as carcinogens and also causing microelectronics damage inside spacecraft and high-flying aircraft. These HZE ions are of concern for radiation protection and radiation shielding technology, because gross rearrangements and mutations and deletions in DNA are expected. Calculations have shown that HZE particles have a strong preference for interaction with light nuclei. The best shield for this radiation would be liquid hydrogen, which is totally impractical. For this reason, hydrogen-containing polymers make the most effective practical shields. Shielding is required during missions in Earth orbit and possibly for frequent flying at high altitude because of the broad GCR spectrum and during a passage into deep space and LunarMars habitation because of the protracted exposure encountered on a long space mission. An additional hazard comes from solar particle events (SPEs) which are mostly energetic protons that can produce heavy ion secondaries as well as neutrons in materials. These events occur at unpredictable times and can deliver a potentially lethal dose within several hours to an unshielded human. Radiation protection for humans requires safety in short-term missions and maintaining career exposure limits within acceptable levels on future long-term exploration missions. The selection of shield materials can alter the protection of humans by an order of magnitude. If improperly selected, shielding materials can actually increase radiation damage due to penetration properties and nuclear fragmentation. Protecting space-borne microelectronics from single event upsets (SEUs) by transmitted radiation will benefit system reliability and system design cost by using optimal shield materials. Long-term missions on the surface of the Moon or Mars will require the construction of habitats to protect humans during their stay. One approach to the construction is to make structural materials from lunar or Martian regolith using a polymeric material as a binder. The hydrogen-containing polymers are considerably more effective for radiation protection than the regolith, but the combination minimizes the amount of polymer to be transported. We have made composites of simulated lunar regolith with two different polymers, LaRC-SI, a high-performance polyimide thermoset, and polyethylene, a thermoplastic.

Kiefer, Richard L.

2002-01-01

203

Biological Diversity of the Guiana Shield: Georeferencing Plants of the Guiana Shield  

E-print Network

Biological Diversity of the Guiana Shield: Georeferencing Plants of the Guiana Shield Eduardo To document, understand, and conserve the biological diversity of the shield area. #12;#12;What does & in Host Country) #12;#12;Georeferencing Plants of the Guiana Shield · The Smithsonian NMNH has conducted

Mathis, Wayne N.

204

Temperature distribution in gamma-ray shielding  

Microsoft Academic Search

Analytical expressions are obtained for the temperature distributions in gamma ray shielding for isotropic and unidirectional beams with boundary conditions of the third kind. These are solved numerically for concrete shielding, and the effects of shield thickness, gamma-ray scattering, boundary conditions and beam geometry on the temperature distribution profile are examined.

D. P. Osanov

1965-01-01

205

Low background shielding of HPGe detector  

Microsoft Academic Search

National Radiation Protection Institute in Prague is equipped with 14 HPGe detectors with relative efficiency up to 150%. Steel shielding with one of these detectors (relative efficiency 100%) was chosen to be rebuilt to decrease minimum detectable activity (MDA). Additional lead and copper shielding was built up inside the original steel shielding to reduce the volume of the inner space

L. Trnková; P. Rulík

2009-01-01

206

University Buildings Landmark Buildings  

E-print Network

Pharmacy S Planning, Architecture and Civil Engineering T Politics, International Studies and Philosophy VKEY University Buildings Landmark Buildings The Lanyon Building Roads Footpath Cafe University Accommodation Queen's University Belfast Campus Map School Offices A Biological Sciences B Chemistry

Paxton, Anthony T.

207

Shielding techniques tackle EMI excesses. V - EMI shielding  

NASA Astrophysics Data System (ADS)

The utilization of shielding gaskets in EMI design is presented in terms of seam design, gasket design, groove design, and fastener spacing. The main function of seam design is to minimize the coupling efficiency of a seam, and for effective shielding, seam design should include mating surfaces which are as flat as possible, and a flange width at least five times the maximum anticipated separation between mating surfaces. Seam surface contact with a gasket should be firm, continuous, and uniform. Gasket height, closure pressure, and compression set as a function of the applied pressure parameters are determined using compression/deflection curves. Environmental seal requirements are given and the most common materials used are neoprene, silicone, butadiene-acrylonitrile, and natural rubber. Groove design is also discussed, considering gasket heights and cross-sectional areas. Finally, fastener spacing is considered, by examining deflection as a percentage of gasket height.

Grant, P.

1982-10-01

208

THE SPLIT SCATTER SHIELD FOR SPACE APPLICATIONS (thesis)  

Microsoft Academic Search

The split seatter shield eonsists of multiple shield sections which are ; separated irom each other. When this type of shield is used outside the ; atmosphere, radiation scattering in each section has a high probability of ; escaping the shield system without rescattering. Consequently, this shield was ; proposed as a replacement for the normal shield unit construction for

Berga

1961-01-01

209

Coated lead shielding protects nuclear plant workers  

SciTech Connect

This article describes how WNP-2 engineers discovered ways to coat lead shielding that enhance radiation protection while reducing lead oxide emissions. Washington Public Power Supply System (WPPSS) developed a coated lead shielding program at its Washington Nuclear Project Unit 2 (WNP-2) nuclear power station that has proven to be a cost-effective way to reduce workers` radiation exposure while improving plant operations. This program uses permanent shields of tongue-in-groove coated lead for straight pipe runs and coated molded shields for valves, Ts and elbows to replace lead wool blankets. The new shielding materials are easy to install, create a more-effective shield, are more compact and make a neater, better-looking installation. The objective of the Shielding Program at WNP-2, a 1,150 MW boiling water reactor that went into operation in 1984, is to minimize total radiation exposure.

Hill, D.A.; Mussman, R.L. Sr.

1996-09-01

210

Thermally isolated deployable shield for spacecraft  

NASA Technical Reports Server (NTRS)

A thermally isolated deployable shield for spacecraft is provided utilizing a plurality of lattice panels stowable generally against the craft and deployable to some fixed distance from the craft. The lattice panels are formed from replaceable shield panels affixed to lattice structures. The lattice panels generally encircle the craft providing 360 degree coverage therearound. Actuation means are provided from translating the shield radially outward from the craft and thermally isolating the shield from the craft. The lattice panels are relatively flexible, allowing the shield to deploy to variable diameters while retaining uniform curvature thereof. Restraining means are provided for holding the shield relatively tight in its stowed configuration. Close-out assemblies provide light sealing and protection of the annular spaces between the deployed shield and the crafts end structure.

Redmon, John W., Jr. (inventor); Miller, Andre E. (inventor); Lawson, Bobby E. (inventor); Cobb, William E. (inventor)

1991-01-01

211

S8DR shield examination  

NASA Technical Reports Server (NTRS)

The SNAP 8 developmental reactor lithium hydride shield was examined after being irradiated for over 7000 hours at relatively low temperature. A crack was located in the seam weld of the containment vessel, probably the result of hot short cracking under thermal stress. The LiH was visually examined at two locations and its appearance was typical of low temperature irradiated LiH. The adherence of the chrome oxide emittance coating was found to be excellent.

Mason, D. G.; Mccurnin, W. R.

1973-01-01

212

Light shield for solar concentrators  

DOEpatents

A solar receiver unit including a housing defining a recess, a cell assembly received in the recess, the cell assembly including a solar cell, and a light shield received in the recess and including a body and at least two tabs, the body defining a window therein, the tabs extending outward from the body and being engaged with the recess, wherein the window is aligned with the solar cell.

Plesniak, Adam P.; Martins, Guy L.

2014-08-26

213

Photonic Bandgap (PBG) Shielding Technology  

NASA Technical Reports Server (NTRS)

Photonic Bandgap (PBG) shielding technology is a new approach to designing electromagnetic shielding materials for mitigating Electromagnetic Interference (EM!) with small, light-weight shielding materials. It focuses on ground planes of printed wiring boards (PWBs), rather than on components. Modem PSG materials also are emerging based on planar materials, in place of earlier, bulkier, 3-dimensional PBG structures. Planar PBG designs especially show great promise in mitigating and suppressing EMI and crosstalk for aerospace designs, such as needed for NASA's Constellation Program, for returning humans to the moon and for use by our first human visitors traveling to and from Mars. Photonic Bandgap (PBG) materials are also known as artificial dielectrics, meta-materials, and photonic crystals. General PBG materials are fundamentally periodic slow-wave structures in I, 2, or 3 dimensions. By adjusting the choice of structure periodicities in terms of size and recurring structure spacings, multiple scatterings of surface waves can be created that act as a forbidden energy gap (i.e., a range of frequencies) over which nominally-conductive metallic conductors cease to be a conductor and become dielectrics. Equivalently, PBG materials can be regarded as giving rise to forbidden energy gaps in metals without chemical doping, analogous to electron bandgap properties that previously gave rise to the modem semiconductor industry 60 years ago. Electromagnetic waves cannot propagate over bandgap regions that are created with PBG materials, that is, over frequencies for which a bandgap is artificially created through introducing periodic defects

Bastin, Gary L.

2007-01-01

214

Steam generator hand hole shielding.  

PubMed

Seabrook Station is an 1198 MWE Pressurized Water Reactor (PWR) that began commercial operation in 1990. Expensive and dose intensive Steam Generator Replacement Projects among PWR operators have led to an increase in steam generator preventative maintenance. Most of this preventative maintenance is performed through access ports in the shell of the steam generator just above the tube sheet known as secondary side hand holes. Secondary side work activities performed through the hand holes are typically performed without the shielding benefit of water in the secondary side of the steam generator. An increase in cleaning and inspection work scope has led to an increase in dose attributed to steam generator secondary side maintenance. This increased work scope and the station goal of maintaining personnel radiation dose ALARA led to the development of the shielding concept described in this article. This shield design saved an estimated 2.5 person-rem (25 person-Smv) the first time it was deployed and is expected to save an additional 50 person-rem (500 person-mSv) over the remaining life of the plant. PMID:10770158

Cox, W E

2000-05-01

215

Design and demonstration of adiabatic quantum-flux-parametron logic circuits with superconductor magnetic shields  

NASA Astrophysics Data System (ADS)

Adiabatic quantum-flux-parametron (AQFP) logic is an energy-efficient superconductor logic with zero static power and very small dynamic power due to adiabatic switching operations. In order to build large-scale digital circuits, we built AQFP logic cells using superconductor magnetic shields, which are necessary in order to avoid unwanted magnetic couplings between the cells and excitation currents. In preliminary experimental tests, we confirmed that the unwanted coupling became negligibly small thanks to the superconductor shields. As a demonstration, we designed a four-to-one multiplexor and a 16-junction full adder using the shielded logic cells. In both circuits, we confirmed correct logic operations with wide operation margins of excitation currents. These results indicate that large-scale AQFP digital circuits can be realized using the shielded logic cells.

Inoue, Kenta; Takeuchi, Naoki; Narama, Tatsuya; Yamanashi, Yuki; Yoshikawa, Nobuyuki

2015-04-01

216

Recommendations for a Static Cosmic Ray Shield for Enriched Germanium Detectors  

SciTech Connect

This document provides a detailed study of cost and materials that could be used to shield the detector material of the international Tonne-scale germanium neutrinoless double-beta decay experiment from hadronic particles from cosmic ray showers at the Earth's surface. This work was motivated by the need for a shield that minimizes activation of the enriched germanium during storage; in particular, when the detector material is being worked on at the detector manufacturer's facility. This work considers two options for shielding the detector material from cosmic ray particles. One option is to use a pre-existing structure already located near the detector manufacturer, such as Canberra Industries in Meriden, Connecticut. The other option is to build a shield onsite at a detector manufacturer's site. This paper presents a cost and efficiency analysis of such construction.

Aguayo Navarrete, Estanislao; Orrell, John L.; Ankney, Austin S.; Berguson, Timothy J.

2011-09-21

217

Development of deep-seated joint sets in the different stages of mountain building: a preliminary study in the northern fold-and-thrust belt of Taiwan  

NASA Astrophysics Data System (ADS)

Systematic joint sets are one of the most common and persistent features within a brittle deformation regime, usually found in intact rocks, such as massive sandstone. However, joint occurrence can take place under different circumstances from very shallow to rather deep crust, which raise challenges for understanding the mechanisms of its development and thus provokes debates in past decades. In this study, we characterize the deformation structures, including micro fault and joint, by comparing their geometric relation with stratigraphic bedding plane. We intend not only to differentiate the relative chronology of different structures but also to determine the chronological orders and stages during thrust stacking processes in which rocks buried to certain depths and then exhumed from depths to surface. We take the northern fold-and-thrust belt of Taiwan as our case study area. The study area is composed of Pleistocene to Oligocene, terrestrial to shallow marine sedimentary deposits, which was exhumed accompanied with a series of imbricate thrusts during the Plio-Pleistocene orogeny of arc-continent collision between the Philippine Sea and Eurasian plates. We study four cross sections from little deformed rock formations in the foreland to intense folded and even slightly metamorphosed terrains in the slate belt, in order to characterize and distinguish different brittle structures at different depths. Particular attention is paid to the development of the joint sets at different depths and their relationship with the bedding plane and other associated deformation features where joints happen to occur. We found that 1) the most predominant joint sets are deep-seated and tectonics related, in comparison with shallow released joints, although their relation with tectonic stress orientation remains inconclusive; 2) the onset depths of development of joint sets can be as shallow as 3-4 km and as deep as 10-15 km. As to whether the development occurs during burial or exhumation, it remains questionable; 3) micro faults with striated slip, mainly under NW-directed compression induced by indentation of the Philippine Sea plate, occur exclusively after formation of persistent joint sets and often during thrust stacking or folding; 4) joint sets often serve as the guiding slip planes for a large portion of strike-slip micro faulting. In contrast, many thrust micro faults use bedding planes for their slip planes, especially during stacking and folding processes.

Lee, Jian-Cheng; Chu, Hao-Tsu; Angelier, Jacques; Begerat, Françoise

2013-04-01

218

Flexible Shields for Protecting Spacecraft Against Debris  

NASA Technical Reports Server (NTRS)

A report presents the concept of Flexshield a class of versatile, lightweight, flexible shields for protecting spacecraft against impacts by small meteors and orbiting debris. The Flexshield concept incorporates elements of, but goes beyond, prior spacecraft-shielding concepts, including those of Whipple shields and, more recently, multi-shock shields and multi-shock blankets. A shield of the Flexshield type includes multiple outer layers (called bumpers in the art) made, variously, of advanced ceramic and/or polymeric fibers spaced apart from each other by a lightweight foam. As in prior such shields, the bumpers serve to shock an impinging hypervelocity particle, causing it to disintegrate vaporize, and spread out over a larger area so that it can be stopped by an innermost layer (back sheet). The flexibility of the fabric layers and compressibility of the foam make it possible to compress and fold the shield for transport, then deploy the shield for use. The shield can be attached to a spacecraft by use of snaps, hook-and-pile patches, or other devices. The shield can also contain multilayer insulation material, so that it provides some thermal protection in addition to mechanical protection.

Christiansen, Eric L.; Crews, Jeanne Lee

2004-01-01

219

EMI Shields made from intercalated graphite composites  

NASA Technical Reports Server (NTRS)

Electromagnetic interference (EMI) shielding typically makes up about twenty percent of the mass of a spacecraft power system. Graphite fiber/polymer composites have significantly lower densities and higher strengths than aluminum, the present material of choice for EMI shields, but they lack the electrical conductivity that enables acceptable shielding effectiveness. Bromine intercalated pitch-based graphite/epoxy composites have conductivities fifty times higher than conventional structural graphite fibers. Calculations are presented which indicate that EMI shields made from such composites can have sufficient shielding at less than 20% of the mass of conventional aluminum shields. EMI shields provide many functions other than EMI shielding including physical protection, thermal management, and shielding from ionizing radiation. Intercalated graphite composites perform well in these areas also. Mechanically, they have much higher specific strength and modulus than aluminum. They also have shorter half thicknesses for x-rays and gamma radiation than aluminum. Thermally, they distribute infra-red radiation by absorbing and re-radiating it rather than concentrating it by reflection as aluminum does. The prospects for intercalated graphite fiber/polymer composites for EMI shielding are encouraging.

Gaier, James R.; Terry, Jennifer

1995-01-01

220

The Feasibility of Multipole Electrostatic Radiation Shielding  

NASA Technical Reports Server (NTRS)

Although passive shielding appears to be the only workable solution for galactic cosmic radiation (GCR), active shielding may play an important augmenting role to control the dose from solar particle events (SPEs). It has been noted that, to meet the guidelines of NCRP Report No. 98 through the six SPEs of 1989, a crew member would need roughly double the passive shielding that is necessary to control the GCR dose . This would dramatically increase spacecraft mass, and so it has been proposed that a small but more heavily shielded storm shelter may be used to protect the crew during SPEs. Since a gradual SPE may last 5 or more days, staying in a storm shelter may be psychologically and physiologically distressing to the crew. Storm shelters do not provide shielding for the spacecraft itself against the SPE radiation, and radiation damage to critical electronics may result in loss of mission and life. Single-event effects during the radiation storm may require quick crew response to maintain the integrity of the spacecraft, and confining the crew to a storm shelter prohibits their attending to the spacecraft at the precise time when that attention is needed the most. Active shielding cannot protect against GCR because the particle energies are too high. Although lower energy particles are easier to stop in a passive shield, such shielding is more satisfactory against GCR than against SPE radiation because of the tremendous difference in their initial fluences. Even a small fraction of the SPE fluence penetrating the passive shielding may result in an unacceptably high dose. Active shielding is more effective than passive shielding against SPE radiation because it offers 100% shielding effectiveness up to the cutoff energy, and significant shielding effectiveness beyond the cutoff as well.

Metzger, Philip T.; Lane, John E.; Youngquist, Robert C.

2004-01-01

221

Exploratory Environmental Tests of Several Heat Shields  

NASA Technical Reports Server (NTRS)

Exploratory tests have been conducted with several conceptual radiative heat shields of composite construction. Measured transient temperature distributions were obtained for a graphite heat shield without insulation and with three types of insulating materials, and for a metal multipost heat shield, at surface temperatures of approximately 2,000 F and 1,450 F, respectively, by use of a radiant-heat facility. The graphite configurations suffered loss of surface material under repeated irradiation. Temperature distribution calculated for the metal heat shield by a numerical procedure was in good agreement with measured data. Environmental survival tests of the graphite heat shield without insulation, an insulated multipost heat shield, and a stainless-steel-tile heat shield were made at temperatures of 2,000 F and dynamic pressures of approximately 6,000 lb/sq ft, provided by an ethylene-heated jet operating at a Mach number of 2.0 and sea-level conditions. The graphite heat shield survived the simulated aerodynamic heating and pressure loading. A problem area exists in the design and materials for heat-resistant fasteners between the graphite shield and the base structure. The insulated multipost heat shield was found to be superior to the stainless-steel-tile heat shield in retarding heat flow. Over-lapped face-plate joints and surface smoothness of the insulated multi- post heat shield were not adversely affected by the test environment. The graphite heat shield without insulation survived tests made in the acoustic environment of a large air jet. This acoustic environment is random in frequency and has an overall noise level of 160 decibels.

Goodman, George P.; Betts, John, Jr.

1961-01-01

222

EMC effects of the lightning protection system: shielding properties of the roof-grid  

Microsoft Academic Search

A suitable set of parameters is used to evaluate the shielding performance of the roof-grid constituted by a mesh of conductors, electrically interconnected, laying on top of buildings with a large-area roof. The influence of the roof-grid on the electromagnetic field inside the building due to a direct lightning strike is shown. The values of the electromotive force induced in

S. Cristina; A. Orlandi

1991-01-01

223

Seismic analysis of the mirror fusion test facility shielding vault  

SciTech Connect

This report presents a seismic analysis of the vault in Building 431 at Lawrence Livermore National Laboratory which houses the mirror Fusion Test Facility. The shielding vault structure is approximately 120 ft long by 80 ft wide and is constructed of concrete blocks approximately 7 x 7 x 7 ft. The north and south walls are approximately 53 ft high and the east wall is approximately 29 ft high. These walls are supported on a monolithic concrete foundation that surrounds a 21-ft deep open pit. Since the 53-ft walls appeared to present the greatest seismic problem they were the first investigated.

Gabrielsen, B.L.; Tsai, K.

1981-04-01

224

Heat flow from the West African shield  

SciTech Connect

The heat flow over Precambrian shields is generally lower than over other continental provinces. Previous observations at 9 sites of the West African shield have shown that heat flow ranges from 20 mW m/sup -2/ in Niger to 38-42 mW m/sup -2/ in Liberia, Ghana and Nigeria. Since some of these values are lower than expected for Precambrian shields, it is important to find out whether or not they are representative of the entire shield before trying to derive its thermal structure. In this paper, we present new heat flow determinations from seven sites of the West African shield. These indicate that the surface heat flow is comparable with that of other Precambrian shields in the world.

Brigaud, F.; Lucazeau, F.; Ly, S.; Sauvage, J.F.

1985-09-01

225

Building No. 918, detail of skirt board and concrete post ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Building No. 918, detail of skirt board and concrete post foundation with termite shield - Presidio of San Francisco, Enlisted Men's Barracks Type, West end of Crissy Field, between Pearce & Maudlin Streets, San Francisco, San Francisco County, CA

226

The ORNL-SNAP shielding program  

NASA Technical Reports Server (NTRS)

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.

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

1972-01-01

227

Hot Cell Window Shielding Analysis Using MCNP  

SciTech Connect

The Idaho National Laboratory Materials and Fuels Complex nuclear facilities are undergoing a documented safety analysis upgrade. In conjunction with the upgrade effort, shielding analysis of the Fuel Conditioning Facility (FCF) hot cell windows has been conducted. This paper describes the shielding analysis methodology. Each 4-ft thick window uses nine glass slabs, an oil film between the slabs, numerous steel plates, and packed lead wool. Operations in the hot cell center on used nuclear fuel (UNF) processing. Prior to the shielding analysis, shield testing with a gamma ray source was conducted, and the windows were found to be very effective gamma shields. Despite these results, because the glass contained significant amounts of lead and little neutron absorbing material, some doubt lingered regarding the effectiveness of the windows in neutron shielding situations, such as during an accidental criticality. MCNP was selected as an analysis tool because it could model complicated geometry, and it could track gamma and neutron radiation. A bounding criticality source was developed based on the composition of the UNF. Additionally, a bounding gamma source was developed based on the fission product content of the UNF. Modeling the windows required field inspections and detailed examination of drawings and material specifications. Consistent with the shield testing results, MCNP results demonstrated that the shielding was very effective with respect to gamma radiation, and in addition, the analysis demonstrated that the shielding was also very effective during an accidental criticality.

Chad L. Pope; Wade W. Scates; J. Todd Taylor

2009-05-01

228

Nipple Shields: A Review of the Literature  

PubMed Central

Abstract Nipple shields have become commonplace in the United States for a wide range of breastfeeding problems. This article is a summary of the current literature describing the evidence for nipple shield use. The authors reviewed all available articles on nipple shields and selected 13 studies for inclusion. The studies were organized into three categories: physiologic responses, premature infants, and mothers' experiences. This review concludes that current published research does not provide evidence for safety or effectiveness of contemporary nipple shield use. PMID:20807104

McKechnie, Anne Chevalier

2010-01-01

229

Relative radiant heat absorption characteristics of two types of mirror shields and a polished aluminum shield  

E-print Network

RELATIVE RADIANT HEAT ABSORPTION CHARACTERISTICS OF TWO TYPES OF MIRROR SHIELDS AND A POLISHED ALUMINUM SHIELD A Thesis by STEVEN DOUGLAS HERRON Submitted to the Graduate College of Texas A&M University in partial fulfillment... of the requirement for the degree of MASTER OF SCIENCE August 1973 Major Subject: Industrial Hygiene RELATIVE RADIANT HEAT ABSORPTION CHARACTERISTICS OF TWO TYPES OF MIRROR SHIELDS AND A POLISHED ALUMINUM SHIELD A Thesis by STEVEN DOUGLAS HERRON Approved...

Herron, Steven Douglas

1973-01-01

230

University Buildings Landmark Buildings  

E-print Network

's University Belfast Campus Map The Lanyon Building The Students' Union The David Keir Building School Offices and Sonic Arts Q Nursing and Midwifery R Pharmacy S Planning, Architecture and Civil Engineering T Politics Accommodation) 5 Harty Room, School of Music 26 Health Sciences Building 3 Human Resources 11 Information

Paxton, Anthony T.

231

Radiation environment and shielding for early manned Mars missions  

NASA Technical Reports Server (NTRS)

The problem of shielding a crew during early manned Mars missions is discussed. Requirements for shielding are presented in the context of current astronaut exposure limits, natural ionizing radiation sources, and shielding inherent in a particular Mars vehicle configuration. An estimated range for shielding weight is presented based on the worst solar flare dose, mission duration, and inherent vehicle shielding.

Hall, Stephen B.; Mccann, Michael E.

1986-01-01

232

Underground barrier construction apparatus with soil-retaining shield  

DOEpatents

An apparatus is described for building a horizontal underground barrier by cutting through soil and depositing a slurry, preferably one which cures into a hardened material. The apparatus includes a digging means for cutting and removing soil to create a void under the surface of the ground, a shield means for maintaining the void, and injection means for inserting barrier-forming material into the void. In one embodiment, the digging means is a continuous cutting chain. Mounted on the continuous cutting chain are cutter teeth for cutting through soil and discharge paddles for removing the loosened soil. This invention includes a barrier placement machine, a method for building an underground horizontal containment barrier using the barrier placement machine, and the underground containment system. Preferably the underground containment barrier goes underneath and around the site to be contained in a bathtub-type containment. 17 figs.

Gardner, B.M.; Smith, A.M.; Hanson, R.W.; Hodges, R.T.

1998-08-04

233

Underground barrier construction apparatus with soil-retaining shield  

DOEpatents

An apparatus for building a horizontal underground barrier by cutting through soil and depositing a slurry, preferably one which cures into a hardened material. The apparatus includes a digging means for cutting and removing soil to create a void under the surface of the ground, a shield means for maintaining the void, and injection means for inserting barrier-forming material into the void. In one embodiment, the digging means is a continuous cutting chain. Mounted on the continuous cutting chain are cutter teeth for cutting through soil and discharge paddles for removing the loosened soil. This invention includes a barrier placement machine, a method for building an underground horizontal containment barrier using the barrier placement machine, and the underground containment system. Preferably the underground containment barrier goes underneath and around the site to be contained in a bathtub-type containment.

Gardner, Bradley M. (Idaho Falls, ID); Smith, Ann Marie (Pocatello, ID); Hanson, Richard W. (Spokane, WA); Hodges, Richard T. (Deer Park, WA)

1998-01-01

234

Construction-technological methods for increasing the strength of the lithium hydride radiation shield of spacecraft nuclear power systems  

Microsoft Academic Search

UDC 629.7.015.4:629.7.064.54+629.7.064.55 The radiation shield of a spacecraft nuclear power system, besides performing its basic function to reduce ionizing radiation to an acceptable level, must also retain its carrying capacity under static and dynamical loading at the stage when the spacecraft is put into orbit and during prolonged operation of the power system. Thus the strength of the radiation shield,

A. G. Eremin; L. S. Korobkov; V. A. Fedorov; L. E. Shishenya

1993-01-01

235

Fundamental Parameters of the SHIELD II Galaxies  

NASA Astrophysics Data System (ADS)

The "Survey of HI in Extremely Low-mass Dwarfs" ("SHIELD") is a multiwavelength, legacy-class observational campaign that is facilitating the study of both internal and global evolutionary processes in 12 low-mass dwarf galaxies discovered in early Arecibo Legacy Fast ALFA (ALFALFA) survey data products. Cycle 19 HST observations of the 12 SHIELD galaxies have allowed us to determine their TRGB distances, thus anchoring the physical scales on which our ongoing analysis is based. Since the inception of SHIELD, the ALFALFA survey has completed data acquisition, thereby populating the faint end of the HI mass function with dozens of SHIELD analogs. In this proposal we request ACS imaging of 18 of these "SHIELD II" galaxies that have already been imaged in the HI spectral line with the WSRT. These data will enable a holistic HST imaging study of the fundamental parameters and characteristics of a statistically robust sample of 30 extremely low-mass galaxies (including 12 SHIELD and 18 SHIELD II systems). The primary science goal is the derivation of TRGB distances; the distance dependence of many fundamental parameters makes HST observations critical for the success of SHIELD II. Additional science goals include an accurate census of the dark matter contents of these galaxies, a spatial and temporal study of star formation within them, and a characterization of the fundamental parameters that change as galaxy masses range from "mini-halo" to star-forming dwarf.

Cannon, John

2014-10-01

236

Shielding effectiveness of superconductive particles in plastics  

SciTech Connect

The ability to cool superconductors with liquid nitrogen instead of liquid helium has opened the door to a wide range of research. The well known Meissner effect, which states superconductors are perfectly diamagnetic, suggests shielding applications. One of the drawbacks to the new ceramic superconductors is the brittleness of the finished material. Because of this drawback, any application which required flexibility (e.g., wire and cable) would be impractical. Therefore, this paper presents the results of a preliminary investigation into the shielding effectiveness of YBa/sub 2/Cu/sub 3/O/sub 7-x/ both as a composite and as a monolithic material. Shielding effectiveness was measured using two separate test methods. One tested the magnetic (near field) shielding, and the other tested the electromagnetic (far field) shielding. No shielding was seen in the near field measurements on the composite samples, and only one heavily loaded sample showed some shielding in the far field. The monolithic samples showed a large amount of magnetic shielding. 5 refs., 5 figs.

Pienkowski, T.; Kincaid, J.; Lanagan, M.T.; Poeppel, R.B.; Dusek, J.T.; Shi, D.; Goretta, K.C.

1988-09-01

237

Shielding Strategies for Human Space Exploration  

NASA Technical Reports Server (NTRS)

A group of twenty-nine scientists and engineers convened a 'Workshop on Shielding Strategies for Human Space Exploration' at the Lyndon B. Johnson Space Center in Houston, Texas. The provision of shielding for a Mars mission or a Lunar base from the hazards of space radiations is a critical technology since astronaut radiation safety depends on it and shielding safety factors to control risk uncertainty appear to be great. The purpose of the workshop was to define requirements for the development and evaluation of high performance shield materials and designs and to develop ideas regarding approaches to radiation shielding. The workshop was organized to review the recent experience on shielding strategies gained in studies of the 'Space Exploration Initiative (SEI),' to review the current knowledge base for making shield assessment, to examine a basis for new shielding strategies, and to recommend a strategy for developing the required technologies for a return to the moon or for Mars exploration. The uniqueness of the current workshop arises from the expected long duration of the missions without the protective cover of the geomagnetic field in which the usually small and even neglected effects of the galactic cosmic rays (GCR) can no longer be ignored. It is the peculiarity of these radiations for which the inter-action physics and biological action are yet to be fully understood.

Wilson J. W. (Editor); Miller, J. (Editor); Konradi, A. (Editor); Cucinotta, F. A. (Editor)

1997-01-01

238

Shielding Strategies for Human Space Exploration  

NASA Astrophysics Data System (ADS)

A group of twenty-nine scientists and engineers convened a 'Workshop on Shielding Strategies for Human Space Exploration' at the Lyndon B. Johnson Space Center in Houston, Texas. The provision of shielding for a Mars mission or a Lunar base from the hazards of space radiations is a critical technology since astronaut radiation safety depends on it and shielding safety factors to control risk uncertainty appear to be great. The purpose of the workshop was to define requirements for the development and evaluation of high performance shield materials and designs and to develop ideas regarding approaches to radiation shielding. The workshop was organized to review the recent experience on shielding strategies gained in studies of the 'Space Exploration Initiative (SEI),' to review the current knowledge base for making shield assessment, to examine a basis for new shielding strategies, and to recommend a strategy for developing the required technologies for a return to the moon or for Mars exploration. The uniqueness of the current workshop arises from the expected long duration of the missions without the protective cover of the geomagnetic field in which the usually small and even neglected effects of the galactic cosmic rays (GCR) can no longer be ignored. It is the peculiarity of these radiations for which the inter-action physics and biological action are yet to be fully understood.

Wilson, J. W.; Miller, J.; Konradi, A.; Cucinotta, F. A.

1997-12-01

239

Flexible shielding system for radiation protection  

NASA Technical Reports Server (NTRS)

Modular construction of low cost flexible radiation shielding panels consists of water filled steels cans, zinc bromide windows, turntable unit, master-slave manipulators, and interlocking lead bricks. Easy modifications of shielding wall thicknesses are obtained by rearranging overall geometry of portable components.

Babin, A.

1972-01-01

240

A SUMMARY OF SHIELDING CONSTANTS FOR CONCRETE  

Microsoft Academic Search

The present knowledge of the shielding constants of concrete is summarized. The densities, elemental compositions, and mixes, where available, are given for a wide range of concretes. From these data, various constants useful for shielding calculations were computed. These constants include the removal cross sections, total cross sections, average thermal neutron absorption cross sections, thermal neutron diffusion coefficients, reciprocal thermal

R. L. Walker; M. Grotenhuis

2009-01-01

241

Thermal neutron shield and method of manufacture  

DOEpatents

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.

Brindza, Paul Daniel; Metzger, Bert Clayton

2013-05-28

242

Current status of methods for shielding analysis  

SciTech Connect

Current methods used in shielding analysis and recent improvements in those methods are discussed. The status of methods development is discussed based on needs cited at the 1977 International Conference on Reactor Shielding. Additional areas where methods development is needed are discussed.

Engle, W.W.

1980-01-01

243

Shielding by an electron surface layer  

Microsoft Academic Search

We seek to determine whether the shielding observed in the electron free-fall experiment could be performed by electrons in a surface layer. An idealized model is used to estimate the shielding of the uniform electric field produced by the gravitational compression of the ionic lattice. We allow for the possibility that the charges in the surface layer can obey either

Richard Squier Hanni; John M. Madey

1978-01-01

244

Studies on the neutron field behind shielding of proton accelerators Part I: Concrete shielding  

NASA Astrophysics Data System (ADS)

Energy- and angular distributions of neutrons behind concrete side shielding of proton accelerators were calculated. Simple arguments are given to understand the characteristic shape of the neutron spectrum. Calculations were repeated to receive data for simple shielding estimations. The dose equivalent attenuation coefficient of concrete for monoenergetic neutrons with energies between 1 and 400 MeV were determined and compared with the coefficient for neutrons leaving an accelerator shield at angles around 90°. Data for shielding gaps in accelerator shielding walls are given as an application. The calculations were performed by using the Monte Carlo codes FLUKA92 and MORSE.

Dinter, H.; Tesch, K.; Dworak, D.

1996-01-01

245

SINEX: SCALE shielding analysis GUI for X-Windows  

SciTech Connect

SINEX (SCALE Interface Environment for X-windows) is an X-Windows graphical user interface (GUI), that is being developed for performing SCALE radiation shielding analyses. SINEX enables the user to generate input for the SAS4/MORSE and QADS/QAD-CGGP shielding analysis sequences in SCALE. The code features will facilitate the use of both analytical sequences with a minimum of additional user input. Included in SINEX is the capability to check the geometry model by generating two-dimensional (2-D) color plots of the geometry model using a new version of the SCALE module, PICTURE. The most sophisticated feature, however, is the 2-D visualization display that provides a graphical representation on screen as the user builds a geometry model. This capability to interactively build a model will significantly increase user productivity and reduce user errors. SINEX will perform extensive error checking and will allow users to execute SCALE directly from the GUI. The interface will also provide direct on-line access to the SCALE manual.

Browman, S.M.; Barnett, D.L.

1997-12-01

246

Repository Waste Package Transporter Shielding Weight Optimization  

SciTech Connect

The Yucca Mountain repository requires the use of a waste package (WP) transporter to transport a WP from a process facility on the surface to the subsurface for underground emplacement. The transporter is a part of the waste emplacement transport systems, which includes a primary locomotive at the front end and a secondary locomotive at the rear end. The overall system with a WP on board weights over 350 metric tons (MT). With the shielding mass constituting approximately one-third of the total system weight, shielding optimization for minimal weight will benefit the overall transport system with reduced axle requirements and improved maneuverability. With a high contact dose rate on the WP external surface and minimal personnel shielding afforded by the WP, the transporter provides radiation shielding to workers during waste emplacement and retrieval operations. This paper presents the design approach and optimization method used in achieving a shielding configuration with minimal weight.

C.E. Sanders; Shiaw-Der Su

2005-02-02

247

A perturbation technique for shield weight minimization  

SciTech Connect

The radiation shield optimization code SWAN (Ref. 1) was originally developed for minimizing the thickness of a shield that will meet a given dose (or another) constraint or for extremizing a performance parameter of interest (e.g., maximizing energy multiplication or minimizing dose) while maintaining the shield volume constraint. The SWAN optimization process proved to be highly effective (e.g., see Refs. 2, 3, and 4). The purpose of this work is to investigate the applicability of the SWAN methodology to problems in which the weight rather than the volume is the relevant shield characteristic. Such problems are encountered in shield design for space nuclear power systems. The investigation is carried out using SWAN with the coupled neutron-photon cross-section library FLUNG (Ref. 5).

Watkins, E.F.; Greenspan, E. (Univ. of California, Berkeley (United States))

1993-01-01

248

Mars Exploration Rover Heat Shield Recontact Analysis  

NASA Technical Reports Server (NTRS)

The twin Mars Exploration Rover missions landed successfully on Mars surface in January of 2004. Both missions used a parachute system to slow the rover s descent rate from supersonic to subsonic speeds. Shortly after parachute deployment, the heat shield, which protected the rover during the hypersonic entry phase of the mission, was jettisoned using push-off springs. Mission designers were concerned about the heat shield recontacting the lander after separation, so a separation analysis was conducted to quantify risks. This analysis was used to choose a proper heat shield ballast mass to ensure successful separation with low probability of recontact. This paper presents the details of such an analysis, its assumptions, and the results. During both landings, the radar was able to lock on to the heat shield, measuring its distance, as it descended away from the lander. This data is presented and is used to validate the heat shield separation/recontact analysis.

Raiszadeh, Behzad; Desai, Prasun N.; Michelltree, Robert

2011-01-01

249

21 CFR 886.4750 - Ophthalmic eye shield.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Ophthalmic eye shield. 886.4750 Section 886.4750...Surgical Devices § 886.4750 Ophthalmic eye shield. (a) Identification. An ophthalmic eye shield is a device that consists of a...

2013-04-01

250

21 CFR 886.4750 - Ophthalmic eye shield.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Ophthalmic eye shield. 886.4750 Section 886.4750...Surgical Devices § 886.4750 Ophthalmic eye shield. (a) Identification. An ophthalmic eye shield is a device that consists of a...

2010-04-01

251

21 CFR 886.4750 - Ophthalmic eye shield.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false Ophthalmic eye shield. 886.4750 Section 886.4750...Surgical Devices § 886.4750 Ophthalmic eye shield. (a) Identification. An ophthalmic eye shield is a device that consists of a...

2014-04-01

252

21 CFR 886.4750 - Ophthalmic eye shield.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Ophthalmic eye shield. 886.4750 Section 886.4750...Surgical Devices § 886.4750 Ophthalmic eye shield. (a) Identification. An ophthalmic eye shield is a device that consists of a...

2011-04-01

253

21 CFR 886.4750 - Ophthalmic eye shield.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Ophthalmic eye shield. 886.4750 Section 886.4750...Surgical Devices § 886.4750 Ophthalmic eye shield. (a) Identification. An ophthalmic eye shield is a device that consists of a...

2012-04-01

254

Demagnetization of magnetically shielded rooms  

SciTech Connect

Magnetically shielded rooms for specific high resolution physiological measurements exploiting the magnetic field, e.g., of the brain (dc-magnetoencephalograpy), low-field NMR, or magnetic marker monitoring, need to be reproducibly demagnetized to achieve reliable measurement conditions. We propose a theoretical, experimental, and instrumental base whereupon the parameters which affect the quality of the demagnetization process are described and how they have to be handled. It is demonstrated how conventional demagnetization equipment could be improved to achieve reproducible conditions. The interrelations between the residual field and the variability at the end of the demagnetization process are explained on the basis of the physics of ferromagnetism and our theoretical predictions are evaluated experimentally.

Thiel, F.; Schnabel, A.; Knappe-Grueneberg, S.; Stollfuss, D.; Burghoff, M. [Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, FB 8.2 Biosignals, Abbestrasse 2-12, 10587 Berlin (Germany)

2007-03-15

255

Spacesuit Radiation Shield Design Methods  

NASA Technical Reports Server (NTRS)

Meeting radiation protection requirements during EVA is predominantly an operational issue with some potential considerations for temporary shelter. The issue of spacesuit shielding is mainly guided by the potential of accidental exposure when operational and temporary shelter considerations fail to maintain exposures within operational limits. In this case, very high exposure levels are possible which could result in observable health effects and even be life threatening. Under these assumptions, potential spacesuit radiation exposures have been studied using known historical solar particle events to gain insight on the usefulness of modification of spacesuit design in which the control of skin exposure is a critical design issue and reduction of blood forming organ exposure is desirable. Transition to a new spacesuit design including soft upper-torso and reconfigured life support hardware gives an opportunity to optimize the next generation spacesuit for reduced potential health effects during an accidental exposure.

Wilson, John W.; Anderson, Brooke M.; Cucinotta, Francis A.; Ware, J.; Zeitlin, Cary J.

2006-01-01

256

Electromagnetic shielding in quantum metrology  

NASA Astrophysics Data System (ADS)

The dynamics of the quantum Fisher information of the parameters of the initial atomic state and atomic transition frequency is studied, in the framework of open quantum systems, for a static polarizable two-level atom coupled in the multipolar scheme to a bath of fluctuating vacuum electromagnetic fields without and with the presence of a reflecting boundary. Our results show that in the case without a boundary, the electromagnetic vacuum fluctuations always cause the quantum Fisher information of the initial parameters and thus the precision limit of parameter estimation to decrease. Remarkably, however, with the presence of a boundary, the quantum Fisher information becomes position and atomic polarization dependent and, as a result, it may be enhanced as compared to that in the case without a boundary and may even be shielded from the influence of the vacuum fluctuations in certain circumstances as if it were a closed system.

Jin, Yao; Yu, Hongwei

2015-02-01

257

Background simulations and shielding calculations  

SciTech Connect

Key improvements in the sensitivity of the underground particle astrophysics experiments can only be achieved if the radiation causing background events in detectors is well understood and proper measures are taken to suppress it. The background radiation arising from radioactivity and cosmic-ray muons is discussed here together with the methods of its suppression. Different shielding designs are considered to attenuate gamma-rays and neutrons coming from radioactivity in rock and lab walls. Purity of materials used in detector construction is analysed and the background event rates due to the presence of radioactive isotopes in detector components are discussed. Event rates in detectors caused by muon-induced neutrons with and without active veto systems are presented leading to the requirements for the depth of an underground laboratory and the efficiency of the veto system.

Kudryavtsev, Vitaly A. [Department of Physics and Astronomy, University of Sheffield, Sheffield, S3 7RH (United Kingdom)

2011-04-27

258

Radiation shielding calculations for MuCool test area at Fermilab  

SciTech Connect

The MuCool Test Area (MTA) is an intense primary beam facility derived directly from the Fermilab Linac to test heat deposition and other technical concerns associated with the liquid hydrogen targets being developed for cooling intense muon beams. In this shielding study the results of Monte Carlo radiation shielding calculations performed using the MARS14 code for the MuCool Test Area and including the downstream portion of the target hall and berm around it, access pit, service building, and parking lot are presented and discussed within the context of the proposed MTA experimental configuration.

Igor Rakhno; Carol Johnstone

2004-05-26

259

E-Beam Processing of Polymer Matrix Composites for Multifunctional Radiation Shielding  

NASA Technical Reports Server (NTRS)

Aliphatic polymers were identified as optimum radiation shielding polymeric materials for building multifunctional structural elements for in-space habitats. Conceptual damage tolerant configurations of polyolefins have been proposed, but many manufacturing issues relied on methods and materials which have sub-optimal radiation shielding characteristics (for example, epoxy matrix and adhesives). In the present approach, we shall investigate e-beam processing technologies for inclusion of high-strength aliphatic polymer reinforcement structures into a highly cross-linked polyolefin matrix. This paper reports the baseline thermo-mechanical properties of low density polyethylene and highly crystallized polyethylene.

Hou, Tan-Hung; Wilson, John W.; Jensen, Brian J.; Thibeault, Sheila A.; Chang, Chie K.; Kiefer, Richard L.

2005-01-01

260

EBT-P gamma-ray-shielding analysis  

Microsoft Academic Search

First, a one-dimensional scoping study was performed for the gamma-ray shield of the ELMO Bumpy Torus proof-of-principle device to define appropriate shielding material and determine the required shielding thickness. The dose-equivalent results are analyzed as a function of the radiation-shield thickness for different shielding options. A sensitivity analysis for the pessimistic case is given. The recommended shielding option based on

Gohar

1983-01-01

261

Integrated Solar Concentrator and Shielded Radiator  

NASA Technical Reports Server (NTRS)

A shielded radiator is integrated within a solar concentrator for applications that require protection from high ambient temperatures with little convective heat transfer. This innovation uses a reflective surface to deflect ambient thermal radiation, shielding the radiator. The interior of the shield is also reflective to provide a view factor to deep space. A key feature of the shield is the parabolic shape that focuses incoming solar radiation to a line above the radiator along the length of the trough. This keeps the solar energy from adding to the radiator load. By placing solar cells along this focal line, the concentration of solar energy reduces the number and mass of required cells. By shielding the radiator, the effective reject temperature is much lower, allowing lower radiator temperatures. This is particularly important for lower-temperature processes, like habitat heat rejection and fuel cell operations where a high radiator temperature is not feasible. Adding the solar cells in the focal line uses the concentrating effect of the shield to advantage to accomplish two processes with a single device. This shield can be a deployable, lightweight Mylar structure for compact transport.

Clark, David Larry

2010-01-01

262

Integrated shielding systems for manned interplanetary spaceflight  

NASA Astrophysics Data System (ADS)

The radiation environment encountered by manned interplanetary missions can have a severe impact on both vehicle design and mission performance. This study investigates the potential impact of radiation protection on interplanetary vehicle design for a manned Mars mission. A systems approach was used to investigate the radiation protection requirements of the sum interplanetary environment. Radiation budgets were developed which result in minimum integrated shielding system masses for both nuclear and non-nuclear powered missions. A variety of system configurations and geometries were assessed over a range of dose constraints. For an annual dose equivalent rate limit of 50 rem/yr, an environmental shielding system composed of a habitat shield and storm shelter was found to result in the lowest total mass. For a limit of 65 rem/yr, a system composed of a sleeping quarters shield was least massive, and resulted in significantly reduced system mass. At a limit of 75 rem/yr, a storm shelter alone was found to be sufficient, and exhibited a further mass reduction. Optimal shielding system results for 10 MWe nuclear powered missions were found to follow along similar lines, with the addition of a reactor shadow shield. A solar minimum galactic cosmic ray spectrum and one anomalously large solar particle event during the course of a two year mission were assumed. Water was assumed for environmental radiation shielding.

George, Jeffrey A.

1992-01-01

263

University Buildings Landmark Buildings  

E-print Network

Building School Offices A Biological Sciences B Chemistry and Chemical Engineering C Education D and Biomedical Sciences P Music and Sonic Arts Q Nursing and Midwifery R Pharmacy S Planning, Architecture (Student Accommodation) 5 Harty Room, School of Music 26 Health Sciences Building 3 Human Resources 11

Müller, Jens-Dominik

264

The SHIELD Multi-Wavelength Archive  

NASA Astrophysics Data System (ADS)

We present WCS-registered data products from the "Survey of HI in Extremely Low-Mass Dwarfs" (SHIELD). This ALFALFA follow-up program targets sources that inhabit the faint end of the HI luminosity function. The final SHIELD data suite includes UV, optical, infrared, and HI imaging, providing a unique opportunity to study the panchromatic properties of low-mass, gas-rich galaxies. Ongoing analysis of the rotational dynamics and patterns of star formation in these systems will be disseminated in forthcoming manuscripts. The final SHIELD data products will be made available to the public on an archival website.

McNichols, Andrew; Teich, Yaron; Cannon, John M.; Adams, Elizabeth A.; Dolphin, Andrew E.; Elson, Edward C.; Giovanelli, Riccardo; Haynes, Martha P.; McQuinn, Kristen B.; Ott, Juergen; Saintonge, Amelie; Salzer, John Joseph; Skillman, Evan D.

2015-01-01

265

Hot cell shield plug extraction apparatus  

DOEpatents

An apparatus is provided for moving shielding plugs into and out of holes in concrete shielding walls in hot cells for handling radioactive materials without the use of external moving equipment. The apparatus provides a means whereby a shield plug is extracted from its hole and then swung approximately 90 degrees out of the way so that the hole may be accessed. The apparatus uses hinges to slide the plug in and out and to rotate it out of the way, the hinge apparatus also supporting the weight of the plug in all positions, with the load of the plug being transferred to a vertical wall by means of a bolting arrangement.

Knapp, Philip A. (Moore, ID); Manhart, Larry K. (Pingree, ID)

1995-01-01

266

Radiation shielding concrete made of Basalt aggregates.  

PubMed

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. PMID:22933408

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

2013-04-01

267

Planetary surface reactor shielding using indigenous materials  

SciTech Connect

The exploration and development of Mars will require abundant surface power. Nuclear reactors are a low-cost, low-mass means of providing that power. A significant fraction of the nuclear power system mass is radiation shielding necessary for protecting humans and/or equipment from radiation emitted by the reactor. For planetary surface missions, it may be desirable to provide some or all of the required shielding from indigenous materials. This paper examines shielding options that utilize either purely indigenous materials or a combination of indigenous and nonindigenous materials.

Houts, Michael G.; Poston, David I.; Trellue, Holly R. [Nuclear Systems Design and Analysis Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Baca, Justin A.; Lipinski, Ronald J. [Nuclear Technology and Research, Sandia National Laboratories, Albuquerque, New Mexico 87185-1146 (United States)

1999-01-22

268

Planetary surface reactor shielding using indigenous materials  

SciTech Connect

The exploration and development of Mars will require abundant surface power. Nuclear reactors are a low-cost, low-mass means of providing that power. A significant fraction of the nuclear power system mass is radiation shielding necessary for protecting humans and/or equipment from radiation emitted by the reactor. For planetary surface missions, it may be desirable to provide some or all of the required shielding from indigenous materials. This paper examines shielding options that utilize either purely indigenous materials or a combination of indigenous and nonindigenous materials. {copyright} {ital 1999 American Institute of Physics.}

Houts, Michael G.; Poston, David I.; Trellue, Holly R. [Nuclear Systems Design and Analysis Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Lipinski, Ronald J. [Nuclear Technology and Research, Sandia National Laboratories, Albuquerque, New Mexico 87185-1146 (United States)

1999-01-01

269

Effects of fluctuating magnetic fields on a superconducting bulk rotor shielded with superconducting rings  

NASA Astrophysics Data System (ADS)

We study the effect of a fluctuating magnetic field, which is one of the technical problems for trapped magnetic fields in a bulk superconductor, to realize a practical bulk superconductor rotating machine. Previous research and other's research has shown that fluctuating magnetic fields reduce the strength of trapped magnetic fields in superconducting bulk modules [1, 2]. This deters development of applications of AC rotating machines because superconducting bulk modules are always exposed to a fluctuating magnetic field. Therefore, it is necessary to develop a method to control decrease of the trapped magnetic field. We propose a method to use the shielding ring of a superconducting wire to achieve this goal and the effects are confirmed experimentally [3]. We are now building test equipment for examining the performance of a shielding ring in a bulk rotating machine. This paper reports the test result for the shielding ring applied to the bulk superconducting rotor that is a part of the test equipment.

Yamagishi, K.; Ogawa, J.; Tsukamoto, O.

2014-05-01

270

Fabrication of transparent and ultraviolet shielding composite films based on graphene oxide and cellulose acetate.  

PubMed

Graphene oxide (GO) has been considered a promising filler material for building polymeric nanocomposites because of its excellent dispersibility and high surface area. In this work, we present the fabrication and characterization of transparent and ultraviolet (UV) shielding composite films based on GO and cellulose acetate (CA). GO sheets were found to be well-dispersed throughout the CA matrix, providing smooth and homogeneous composite films. Moreover, the GO sheets were completely embedded within the CA matrix and no presence of this nanomaterial was found at the surface. Nevertheless, CAGO composite films offered an improved high energy light-shielding capacity when compared to pristine CA films. Particularly for UVC irradiation, the CAGO film containing 0.50wt% GO displayed a UV-shielding capacity of 57%, combined with 79% optical transparency under visible light. These CAGO composite films can be potentially applied as transparent UV-protective coatings for packing biomedical, pharmaceutical, and food products. PMID:25843853

de Moraes, Ana Carolina Mazarin; Andrade, Patricia Fernanda; de Faria, Andreia Fonseca; Simões, Mateus Batista; Salomão, Francisco Carlos Carneiro Soares; Barros, Eduardo Bedê; Gonçalves, Maria do Carmo; Alves, Oswaldo Luiz

2015-06-01

271

Stages of Colon Cancer  

MedlinePLUS

... I Stage II Stage III Stage IV After colon cancer has been diagnosed, tests are done to find ... lung cancer . The following stages are used for colon cancer: Stage 0 (Carcinoma in Situ) Stage 0 (colon ...

272

Ablative shielding for hypervelocity projectiles  

NASA Technical Reports Server (NTRS)

A hypervelocity projectile shield which includes a hollow semi-flexible housing fabricated from a plastic like, or otherwise transparent membrane which is filled with a fluid (gas or liquid) is presented. The housing has a inlet valve, similar to that on a tire or basketball, to introduce an ablating fluid into the housing. The housing is attached by a Velcro mount or double-sided adhesive tape to the outside surface of a structure to be protected. The housings are arrayed in a side-by-side relationship for complete coverage of the surface to be protected. In use, when a hypervelocity projectile penetrates the outer wall of a housing it is broken up and then the projectile is ablated as it travels through the fluid, much like a meteorite 'burns up' as it enters the earth's atmosphere, and the housing is deflated. The deflated housing can be easily spotted for replacement, even from a distance. Replacement is then accomplished by simply pulling a deflated housing off the structure and installing a new housing.

Rucker, Michelle A. (inventor)

1993-01-01

273

SP-100 low mass shield design  

SciTech Connect

The shielding considerations for an unmanned space reactor system are somewhat different from those for a terrestrial reactor. An unmanned operation in space implies that only a shadow shield, rather than a 4..pi.. one, is required to protect payload hardware that typically can tolerate 10/sup 4/ to 10/sup 6/ times more radiation than can a human crew. On the other hand, the system mass, of which the radiation shield can be a significant fraction, is a severe constraint for space reactors and not normally a problem with terrestrial ones. The object of this paper is to briefly summarize advancements made on various aspects of low mass shield design for space reactors, including materials and their arrangements, geometric factors and their potential impact on system design optimization, and proposed new configuration concepts for further mass reduction.

Carlson, D.E.

1985-01-01

274

Shield Design for Lunar Surface Applications  

NASA Astrophysics Data System (ADS)

A shielding concept for lunar surface applications of nuclear power is presented herein. The reactor, primary shield, reactor equipment and power generation module are placed in a cavity in the lunar surface. Support structure and heat rejection radiator panels are on the surface, outside the cavity. The reactor power of 1,320 kWt was sized to deliver 50 kWe from a thermoelectric power conversion subsystem. The dose rate on the surface is less than 0.6 mRem/hr at 100 meters from the reactor. Unoptimized shield mass is 1,020 kg which is much lighter than a comparable 4? shield weighing in at 17,000 kg.

Johnson, Gregory A.

2006-01-01

275

Boron-10 loaded inorganic shielding material  

NASA Technical Reports Server (NTRS)

Shielding material containing Boron 10 and gadoliunium for neutron absorption has been developed to reduce interference from low energy neutrons in measurement of fission neutron spectrum using Li-6 fast neutron spectrometer.

Baker, S. I.; Ryskiewicz, R. S.

1972-01-01

276

The design of reactive shielded magnet clutches  

NASA Technical Reports Server (NTRS)

The design of reactive shielded magnet clutches is considered along with their schematics, design formulas and characteristics of clutches in general. The design method suggested makes it possible to reduce calculation errors to 10%.

Gertsov, S. M.

1978-01-01

277

Comparison of graphite, aluminum, and TransHab shielding material characteristics in a high-energy neutron field  

NASA Technical Reports Server (NTRS)

Space radiation transport models clearly show that low atomic weight materials provide a better shielding protection for interplanetary human missions than high atomic weight materials. These model studies have concentrated on shielding properties against charged particles. A light-weight, inflatable habitat module called TransHab was built and shown to provide adequate protection against micrometeoroid impacts and good shielding properties against charged particle radiation in the International Space Station orbits. An experiment using a tissue equivalent proportional counter, to study the changes in dose and lineal energy spectra with graphite, aluminum, and a TransHab build-up as shielding, was carried out at the Los Alamos Nuclear Science Center neutron facility. It is a continuation of a previous study using regolith and doped polyethylene materials. This paper describes the results and their comparison with the previous study. Published by Elsevier Science Ltd.

Badhwar, G. D.; Huff, H.; Wilkins, R.; Thibeault, Sheila

2002-01-01

278

Investigation of Turkish marbles as shielding materials  

Microsoft Academic Search

The natural Turkish marbles, especially Usak Green (UG), Aegean Purple (AP) and Marmara White (MW) were tested as shielding materials using standard gamma sources such as Co-60, Cs-137 and Eu-152. The experiment showed that UG, AP and MW are very effective shields against gamma-rays. The result for this experiment is that the gamma-ray attenuation coefficients of UG, AP and MW

Hamit Atasoy; Gökçe Tarcan; Sema Dökmen

1992-01-01

279

On-orbit analysis of radiation shielding  

Microsoft Academic Search

Ground- and space-based experiments have validated the selection of polyethylene as an effective shield for radiation protection of humans from cosmic radiation exposure during spaceflight. Theoretical models that describe the physical interactions and transport of energetic ions through matter first identified the superior shielding performance of hydrogenous materials. Analytical transport models of space-like particle beams predicted that water would out-perform

M. R. Shavers; F. A. Cucinotta; M. J. Golightly; N. Zapp; V. Petrov; J. W. Wilson; J. E. Nealy; J. Miller; C. Zeitlin; L. Heilbronn

2004-01-01

280

Nuclear reactor shield including magnesium oxide  

DOEpatents

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.

Rouse, Carl A. (Del Mar, CA); Simnad, Massoud T. (La Jolla, CA)

1981-01-01

281

Shielded beam delivery apparatus and method  

DOEpatents

An apparatus includes a plasma generator aligned with a beam generator for producing a plasma to shield an energized beam. An electrode is coaxially aligned with the plasma generator and followed in turn by a vortex generator coaxially aligned with the electrode. A target is spaced from the vortex generator inside a fluid environment. The electrode is electrically biased relative to the electrically grounded target for driving the plasma toward the target inside a vortex shield.

Hershcovitch, Ady; Montano, Rory Dominick

2006-07-11

282

X-ray transmissive debris shield  

DOEpatents

A composite window structure is described for transmitting x-ray radiation and for shielding radiation generated debris. In particular, separate layers of different x-ray transmissive materials are laminated together to form a high strength, x-ray transmissive debris shield which is particularly suited for use in high energy fluences. In one embodiment, the composite window comprises alternating layers of beryllium and a thermoset polymer.

Spielman, Rick B. (Albuquerque, NM)

1994-01-01

283

A shielding theory for upward lightning  

SciTech Connect

A new shielding theory is proposed based on the assumption that the occurrence of lightning strokes on the Japan Sea coast in winter is due to the inception of upward leaders from tall structures. Ratios of the numbers of lightning strokes to high structures observed there in winter show reasonable agreement with values calculated by this theory. Shielding characteristics of a high structure in various conditions are predicted.

Shindo, Takatoshi; Aihara, Yoshinori (Central Research Inst. of Electric Power Industry, Tokyo (Japan))

1993-01-01

284

Space shuttle holddown post blast shield  

NASA Technical Reports Server (NTRS)

The original and subsequent designs of the Solid Rocket Booster/Holddown Post blast shield assemblies and their associated hardware are described. It presents the major problems encountered during their early use in the Space Shuttle Program, during the Return-to-Flight Modification Phase, and during their fabrication and validation testing phases. The actions taken to correct the problems are discussed, along with the various concepts now being considered to increase the useful life of the blast shield.

Larracas, F. B.

1991-01-01

285

Experimental results on MgB2 used as ADR magnetic shields, and comparison to NbTi  

NASA Astrophysics Data System (ADS)

Adiabatic Demagnetization Refrigerator (ADR) is an efficient way to obtain sub-Kelvin temperatures in space environments. The SAFARI instrument for the Japanese spaceborne SPICA mission features detectors which will be cooled down to 50 mK. This cooling will be done by a hybrid cooler comprising a 300 mK sorption stage and a 50 mK ADR stage. For this cooler and ADR in general, the main contribution to the overall mass is in the magnetic system and particularly in the magnetic shielding required to keep the stray field within acceptable values. In order to reduce this mass, superconducting materials can be used as active magnetic shields thanks to un-attenuated eddy currents generated while ramping the magnet current. In this way they could reduce the need of heavy ferromagnetic material shields and increase the shielding efficiency to reach very low parasitic values. In the framework of SAFARI we have built a numerical model of a superconductor magnetic shield. The good results regarding the weight gain lead us to an experimental confirmation. In this paper we present an experimental study on MgB2 and NbTi superconducting materials. 2 pairs of rings of typical diameter of 80 mm have been tested using a superconducting magnet matching closely the dimensions of the SAFARI ADR cooler. The magnetic shielding measurements have been compared to a numerical model.

Prouvé, T.; Duval, J. M.; Luchier, N.; D'escrivan, S.

2014-11-01

286

Reliability Methods for Shield Design Process  

NASA Technical Reports Server (NTRS)

Providing protection against the hazards of space radiation is a major challenge to the exploration and development of space. The great cost of added radiation shielding is a potential limiting factor in deep space operations. In this enabling technology, we have developed methods for optimized shield design over multi-segmented missions involving multiple work and living areas in the transport and duty phase of space missions. The total shield mass over all pieces of equipment and habitats is optimized subject to career dose and dose rate constraints. An important component of this technology is the estimation of two most commonly identified uncertainties in radiation shield design, the shielding properties of materials used and the understanding of the biological response of the astronaut to the radiation leaking through the materials into the living space. The largest uncertainty, of course, is in the biological response to especially high charge and energy (HZE) ions of the galactic cosmic rays. These uncertainties are blended with the optimization design procedure to formulate reliability-based methods for shield design processes. The details of the methods will be discussed.

Tripathi, R. K.; Wilson, J. W.

2002-01-01

287

FORESTRY BUILDING: BUILDING EMERGENCY PLAN  

E-print Network

FORESTRY BUILDING: BUILDING EMERGENCY PLAN Date Adopted: August 18, 2009 Date Revised June 17, 2013 Prepared By: Diana Evans and Jennifer Meyer #12;PURDUE UNIVERSITY BUILDING EMERGENCY PLAN VERSION 3 2 Table Suspension or Campus Closure SECTION 3: BUILDING INFORMATION 3.1 Building Deputy/Alternate Building Deputy

288

J STAGE  

NSDL National Science Digital Library

Developed by the Japan Science and Technology Corporation (JST), J-STAGE (The Japan Science and Technology Aggregator, Electronic) is a recently launched electronic journal center that publishes and disseminates Japanese electronic scientific journals. At present, the site hosts four journals (one of which is Japanese only), but expects to add over a hundred in the near future. The three available English-language journals include the Japanese Journal of Applied Physics, the Journal of the Physical Society of Japan, and SHIGEN-TO-SOZAI, a journal of the Mining and Materials Processing Institute of Japan. The full-text articles are available free of charge with searchable back issues also available.

289

Mountain Stage  

NSDL National Science Digital Library

Mountain Stage, a famous Charleston, West Virginia, venue where folk musicians play, is broadcast on National Public Radio, and can be heard on the NPR website, simply by clicking on "Listen", next to the artist's picture and brief bio. Visitors wishing to read more about the artist's musical history can click on the name of the artist next to their picture. Included in the history is their set list for the broadcast show. Visitors can comment on each artist's show, or recommend it to other visitors, by clicking on the icons at the bottom of each brief bio on the homepage.

290

Commercial Building Partners Catalyze High Performance Buildings Across the Nation  

SciTech Connect

In 2008 the US Department of Energy (DOE) launched the Commercial Buildings Partnership (CBP) project to accelerate market adoption of commercially available energy saving technologies into the design process for new and upgraded commercial buildings. The CBP represents a unique collaboration between industry leaders and DOE to develop high performance buildings as a model for future construction and renovation. CBP was implemented in two stages. This paper focuses on lessons learned at Pacific Northwest National Laboratory (PNNL) in the first stage and discusses some partner insights from the second stage. In the first stage, PNNL and the National Renewable Energy Laboratory recruited CBP partners that own large portfolios of buildings. The labs provide assistance to the partners' design teams and make a business case for energy investments.

Baechler, Michael C.; Dillon, Heather E.; Bartlett, Rosemarie

2012-08-01

291

[Verification of the protective effect of a testicular shield in postoperative radiotherapy for seminoma].  

PubMed

In postoperative radiotherapy for seminoma, control of the testicular absorbed dose is important, since exposure of the testis can lead to temporary or permanent infertility. In this case, instead of using a dog-leg-shaped field, treatment using a field focused near the aorta was provided in several disease stages of seminoma. However, the precise need for testicular shielding during treatment and dose of testis exposure was not clear. We examined these questions by measuring the testicular absorbed dose with and without a testicular shield using two clinical treatment plans and a phantom. The distance from the testis phantom and the lower end of the irradiation field was varied. Where the total dose for the tumor was 20 Gy, the testicular absorbed dose was below 0.1 Gy, the threshold dose for temporary infertility. At this dosage, the distance between the testis phantom and the edge of the irradiation field was 14.6 cm without the shield and 9.99 cm with the shield. Using a testes shield, it was thus possible to reduce the dose by 58.5%. PMID:25242597

Matsumoto, Yoshitsugu; Umezu, Yoshiyuki; Fujibuchi, Toshioh; Noguchi, Yoshitaka; Fukunaga, Jyunichi; Kimura, Tomoko; Hirano, Naomi; Hirose, Takaaki; Sonoda, Shinjiro; Matsumoto, Ryoji

2014-09-01

292

Investigation of photon shielding property changes in curing high density concrete.  

PubMed

High density concrete is usually used for radiation shielding around radiotherapy treatment rooms. Because the concrete is specified differently at the design, construction, and verification stages, the relationship between the intended performance and the actual performance of the shielding material might not be entirely clear. In this study, cylindrical samples of high density shielding concrete were taken as each section of a new radiotherapy bunker was poured. The shielding performance of each sample [measured by beam attenuation and tenth-value layers (TVL)] was evaluated for 15 MV and 6 MV x-ray beams and for the 1.25 MeV monoenergetic gamma beam from a Co source. Transmission curves to 3 TVL were mapped for a representative sample. The samples were also imaged and analyzed using Co Cone Beam Computed Tomography (CoCBCT). Results indicate no significant change in the TVL of high density concrete samples as they cure. The minor fluctuations in shielding properties observed are explained by the heterogeneous structure of the samples as indicated in the CoCBCT images. PMID:23982607

Marsh, Matthew B; Peters, Christopher; Rawluk, Nicholas; Schreiner, L John

2013-10-01

293

Heat flow and thermal structure of the lithosphere across the Baltic Shield and northern Tornquist Zone  

NASA Astrophysics Data System (ADS)

Terrestrial heat-flow data from Archean and Proterozoic Provinces of the Baltic Shield, its southwestern margin, and the tectonic transition to the younger tectonic units of Central Europe (northern segment of the European Geotraverse) are compiled and examined for local and regional variations. A 2-D numerical lithospheric temperature and heat-flux model is presented covering 1800 km of the deep seismic FENNOLORA profile across the Baltic Shield and 500 km of EUGENO-S/ northern EUGEMI seismic lines across the northern Tornquist Zone and the Danish and North German basins. Thermal lithosphere, defined as the outer layer with relatively low temperatures ( T < 1200-1400° C) in which heat transfer is dominantly by conduction, is found to vary markedly in thickness from 85-110 km beneath basins and Tornquist Zone to about 150 km in central shield areas, and 200-250 km in areas of low heat flow along the northern shield profile. These results are in very good agreement with seismological information from surface wave dispersion analysis and the refraction / wide-angle seismic interpretation of FENNOLORA data. The combined thermal and seismologic evidence indicates that the uppermost mantle region stratified in seismic velocity is restricted to the upper, relatively cold thermal layer, which is interpreted to constitute shield lithosphere. Local and to some extent regional variations in surface heat flow are found to be closely related to variations in near-surface radiogenic heat production. For the southern Baltic Shield a heat-flow / heat-production relationship of q0 = 32.8 + 7.6 H0 is derived. Regional increase in heat flow from northern and central shield provinces to the shield margin and the Tornquist Zone is interpreted to be related partly to differences in upper-crustal heat generation, partly, and in southernmost areas mainly, to an increased heat flux from the upper mantle. Upper-mantle heat flux is estimated at 20-25 mW m -2 along the northern and central shield transect, increasing to 30-40 mW m -2 beneath the shield margin, basins, and Tornquist Zone. Lithospheric thickness variations in this region of northern Europe are found to be closely associated with variations in heat flux from the uppermost mantle and perhaps to a large extent controlled by geodynamically determined lateral differences in upper-mantle heat flux. Earthquake focal depth data and information on crustal strength show Baltic Shield seismicity to be limited generally to the upper 20-25 km brittle part of the crust at temperatures less than 300-400°C. Maximum source depth of magnetic anomalies at temperatures near 600°C is in the deepest part of the crust near the crust-mantle boundary in the southern region (about 25 km depth along the Tornquist Zone and about 35-40 km in southern shield areas) and in the uppermost mantle (60-70 km depth) in the northern shield areas. Some petrologic implications are discussed. The present deep crust is supposed to be at lower temperature-pressure conditions than at early stages of formation. However, also the present deepest parts of the shield crust (> 35-40 km) are within the stability field of eclogites. The general absence of significant gravity anomalies in areas of marked crustal thickness variations indicate high-density eclogites to be present in significant amounts in the deep shield crust.

Balling, Niels

1995-04-01

294

BUILDING NAME HEYDON-LAURENCE BUILDING  

E-print Network

BUILDING NAME HEYDON-LAURENCE BUILDING PHARMACY AND BANK BUILDING JOHN WOOLEY BUILDING OLD TEARCHER'S BUILDING PHYSICS BUILDING BAXTER'S LODGE INSTITUTE BUILDING CONSERVATION WORKS R.D.WATT BUILDING MACLEAY BUILDING THE QUARANGLE BADHAM BUILDING J.D. STEWART BUILDING BLACKBURN BUILDING MADSEN BUILDING STORE

Viglas, Anastasios

295

Atlas SCT/Pixel Grounding and Shielding Note 1 ATLAS SCT/Pixel Grounding and Shielding Note  

E-print Network

Atlas SCT/Pixel Grounding and Shielding Note 1 ATLAS SCT/Pixel Grounding and Shielding Note for SCT. This proposal mostly connects existing mechanical and electrical conductive #12;Atlas SCT. The barrel outer heat shield (150 µm aluminum) is the main element of the shield. #12;Atlas SCT

California at Santa Cruz, University of

296

Shielding of manned space vehicles against protons and alpha particles  

NASA Technical Reports Server (NTRS)

The available information on the shielding of manned space vehicles against protons and alpha particles is summarized. The emphasis is placed on shielding against Van Allen belt protons and against solar-flare protons and alpha particles, but information on shielding against galactic cosmic rays is also presented. The approximation methods for use by nonexperts in the space shielding field are those that are standard in the space shielding literature.

Alsmiller, R. G., Jr.; Santoro, R. T.; Barish, J.; Claiborne, H. C.

1972-01-01

297

PBF Reactor Building (PER620) basement, inside cubicle 13. Lead bricks ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

PBF Reactor Building (PER-620) basement, inside cubicle 13. Lead bricks shield the fission product detection system (FPDS). The system detected fission products in pressure loop from in-pile tube. shielding was to prevent other radiation in cubicle from interfering. Assembly of bricks in foreground will slide back to enclose and shield equipment in the three chambers. Date: 1982. INEEL negative no. 82-6376 - Idaho National Engineering Laboratory, SPERT-I & Power Burst Facility Area, Scoville, Butte County, ID

298

Magnetic shielding of interplanetary spacecraft against solar flare radiation  

NASA Technical Reports Server (NTRS)

The ultimate objective of this work is to design, build, and fly a dual-purpose, piggyback payload whose function is to produce a large volume, low intensity magnetic field and to test the concept of using such a magnetic field (1) to protect spacecraft against solar flare protons, (2) to produce a thrust of sufficient magnitude to stabilize low satellite orbits against orbital decay from atmospheric drag, and (3) to test the magsail concept. These all appear to be capable of being tested using the same deployed high temperature superconducting coil. In certain orbits, high temperature superconducting wire, which has now been developed to the point where silver-sheathed high T sub c wires one mm in diameter are commercially available, can be used to produce the magnetic moments required for shielding without requiring any mechanical cooling system. The potential benefits of this concept apply directly to both earth-orbital and interplanetary missions. The usefulness of a protective shield for manned missions needs scarcely to be emphasized. Similarly, the usefulness of increasing orbit perigee without expenditure of propellant is obvious. This payload would be a first step in assessing the true potential of large volume magnetic fields in the US space program. The objective of this design research is to develop an innovative, prototype deployed high temperature superconducting coil (DHTSC) system.

Cocks, Franklin H.; Watkins, Seth

1993-01-01

299

Correlation between shielding effectiveness measurements and alternative methods for the characterization of shielding materials  

Microsoft Academic Search

The correlation between different methods for the characterization of shielding materials is discussed. It is found that a good agreement is obtained using basic methods, such as a four-point resistance measurement, or standard shielding effectiveness methods and using other methods allowing a quick control in the field during injection moulding process

J. A. Catrysse; M. de Goeije; W. Steenbakkers; L. Anaf

1993-01-01

300

LPT. Shield test facility (TAN645 and 646). Calibration lab shield ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

LPT. Shield test facility (TAN-645 and -646). Calibration lab shield door. Ralph M. Parsons 1229-17 ANP/GE-6-645-MS-1. April 1957. Approved by INEEL Classification Office for public release. INEEL index code no. 037-0645-40-693-107369 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID

301

Stages of Breast Cancer  

MedlinePLUS

... IIIA Stage IIIB Stage IIIC Stage IV After breast cancer has been diagnosed, tests are done to find ... bone cancer . The following stages are used for breast cancer: This section describes the stages of breast cancer . ...

302

Investigation of neutron shielding efficiency and radioactivity of concrete shields containing colemanite  

NASA Astrophysics Data System (ADS)

In this work, colemanite, a boron-bearing ore, was added to ordinary Portland concrete as aggregate. Some concrete blocks containing different amounts of colemanite were produced and their neutron permeability and compressive strength were determined. From the results of the experiments, taking into account the nuclear and structural properties of shielding material, a proper colemanite adding ratio was presented. A neutron transport calculation of the shield containing colemanite was made by using the removal-diffusion technique and the decrease in shield thickness, compared to ordinary Portland concrete, was found. Assuming a 20-year stepwise irradiation, the neutron-induced activity within the shield was calculated. Cooling time after shutdown was taken up to 10 5 years. By comparing the total and elemental activities of the ordinary and colemanite-added Portland concretes, the contribution of colemanite to the shield activity was investigated.

Yarar, Yasemin; Bayülken, Ahmet

1994-09-01

303

Shielding Structures for Interplanetary Human Mission  

NASA Astrophysics Data System (ADS)

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 radiation shielding power of the interplanetary habitat structures, like the spacecraft shell, minimizing the amount of mass used. From the radiation protection point of view the spacecraft shell is an interesting spacecraft system because it surrounds almost homogeneously all the habitat and it is typically composed by the Micrometeorites and Debris Protection Systems (MDPS), the Multilayer Insulation (MLI) for thermal control purposes, and the primary structure that offers the pressure containment functionality. Nevertheless, the spacecraft internal outfitting is important to evaluate the different shielded areas in the habitat. Using Geant4 Monte Carlo simulations toolkit through GRAS (Geant4 Radiation Analysis for Space) tool, different spacecraft structures will be analyzed for their shielding behavior in terms of fluxes, dose reduction and radiation quality, and for their implementation in a real pressurized module. Effects on astronauts and electronic equipments will be also assessed with respect to the standard aluminum structures.

Tracino, Emanuele; Lobascio, Cesare

2012-07-01

304

Analytic Ballistic Performance Model of Whipple Shields  

NASA Technical Reports Server (NTRS)

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.

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

2015-01-01

305

Asymmetric Electrostatic Radiation Shielding for Spacecraft  

NASA Technical Reports Server (NTRS)

A paper describes the types, sources, and adverse effects of energetic-particle radiation in interplanetary space, and explores a concept of using asymmetric electrostatic shielding to reduce the amount of such radiation impinging on spacecraft. Typically, such shielding would include a system of multiple inflatable, electrically conductive spheres deployed in clusters in the vicinity of a spacecraft on lightweight structures that would maintain the spheres in a predetermined multipole geometry. High-voltage generators would maintain the spheres at potential differences chosen in conjunction with the multipole geometry so that the resulting multipole field would gradually divert approaching energetic atomic nuclei from a central region occupied by the spacecraft. The spheres nearest the center would be the most positive, so as to repel the positively charged impinging nuclei from the center. At the same time, the monopole potential of the overall spacecraft-and-shielding system would be made negative so as to repel thermal electrons. The paper presents results of computational simulations of energetic-particle trajectories and shield efficiency for a trial system of 21 spheres arranged in three clusters in an overall linear quadrupole configuration. Further development would be necessary to make this shielding concept practical.

Metzger, Philip T.; Youngquist, Robert C.; Lane, John E.

2005-01-01

306

Microscreen radiation shield for thermoelectric generator  

DOEpatents

The present invention provides a microscreen radiation shield which reduces radiative heat losses in thermoelectric generators such as sodium heat engines without reducing the efficiency of operation of such devices. The radiation shield is adapted to be interposed between a reaction zone and a means for condensing an alkali metal vapor in a thermoelectric generator for converting heat energy directly to electrical energy. The radiation shield acts to reflect infrared radiation emanating from the reaction zone back toward the reaction zone while permitting the passage of the alkali metal vapor to the condensing means. The radiation shield includes a woven wire mesh screen or a metal foil having a plurality of orifices formed therein. The orifices in the foil and the spacing between the wires in the mesh is such that radiant heat is reflected back toward the reaction zone in the interior of the generator, while the much smaller diameter alkali metal atoms such as sodium pass directly through the orifices or along the metal surfaces of the shield and through the orifices with little or no impedance.

Hunt, Thomas K. (Ann Arbor, MI); Novak, Robert F. (Farmington Hills, MI); McBride, James R. (Ypsilanti, MI)

1990-01-01

307

Correlated Uncertainties in Radiation Shielding Effectiveness  

NASA Technical Reports Server (NTRS)

The space radiation environment is composed of energetic particles which can deliver harmful doses of radiation that may lead to acute radiation sickness, cancer, and even death for insufficiently shielded crew members. Spacecraft shielding must provide structural integrity and minimize the risk associated with radiation exposure. The risk of radiation exposure induced death (REID) is a measure of the risk of dying from cancer induced by radiation exposure. Uncertainties in the risk projection model, quality factor, and spectral fluence are folded into the calculation of the REID by sampling from probability distribution functions. Consequently, determining optimal shielding materials that reduce the REID in a statistically significant manner has been found to be difficult. In this work, the difference of the REID distributions for different materials is used to study the effect of composition on shielding effectiveness. It is shown that the use of correlated uncertainties allows for the determination of statistically significant differences between materials despite the large uncertainties in the quality factor. This is in contrast to previous methods where uncertainties have been generally treated as uncorrelated. It is concluded that the use of correlated quality factor uncertainties greatly reduces the uncertainty in the assessment of shielding effectiveness for the mitigation of radiation exposure.

Werneth, Charles M.; Maung, Khin Maung; Blattnig, Steve R.; Clowdsley, Martha S.; Townsend, Lawrence W.

2013-01-01

308

Experimental evaluation of resistojet thruster plume shields  

NASA Technical Reports Server (NTRS)

The exhaust of an engineering model resistojet has been investigated using rotary pitot probes and a rotary quartz crystal microbalance. The resistojet operated on CO2 propellant at a mass flow rate of 0.29 g/sec in both heated and unheated flows. Measurements of local flow angles in the near field of a conical plume shield indicated that the shield was not wholly effective in confining the flow to the region upstream of its exit plane. However, the absolute levels of the measured mass flux into the backflow region were very low, on the order of 7 x 10 to the -7 power g/sqcm/sec or less. The use of a circualr disk at the exit plane of the existing conical shield showed some benefit in decreasing the amount of backflow by a factor of two. Lastly, a detached shield placed upstream of the resistojet exit plane demonstrated a small degree of local shielding for the region directly behind it.

Carney, Lynnette M.; Bailey, Allan B.

1988-01-01

309

Experimental evaluation of resistojet thruster plume shields  

NASA Technical Reports Server (NTRS)

The exhaust of an engineering model resistojet has been investigated using rotary pitot probes and a rotary quartz crystal microbalance. The resistojet operated on CO2 propellant at a mass flow rate of 0.29 g/sec in both heated and unheated flows. Measurements of local flow angles in the near field of a conical plume shield indicated that the shield was not wholly effective in confining the flow to the region upstream of its exit plane. However, the absolute levels of the measured mass flux into the backflow region were very low, on the order of 7 x 10 to the -7 power g/sq cm/sec or less. The use of a circular disk at the exit plane of the existing conical shield showed some benefit in decreasing the amount of backflow by a factor of two. Lastly, a detached shield placed upstream of the resistojet exit plane demonstrated a small degree of local shielding for the region directly behind it.

Carney, Lynnette M.; Bailey, Allan B.

1988-01-01

310

Cosmic Ray Interactions in Shielding Materials  

SciTech Connect

This document provides a detailed study of materials used to shield against the hadronic particles from cosmic ray showers at Earth’s surface. This work was motivated by the need for a shield that minimizes activation of the enriched germanium during transport for the MAJORANA collaboration. The materials suitable for cosmic-ray shield design are materials such as lead and iron that will stop the primary protons, and materials like polyethylene, borated polyethylene, concrete and water that will stop the induced neutrons. The interaction of the different cosmic-ray components at ground level (protons, neutrons, muons) with their wide energy range (from kilo-electron volts to giga-electron volts) is a complex calculation. Monte Carlo calculations have proven to be a suitable tool for the simulation of nucleon transport, including hadron interactions and radioactive isotope production. The industry standard Monte Carlo simulation tool, Geant4, was used for this study. The result of this study is the assertion that activation at Earth’s surface is a result of the neutronic and protonic components of the cosmic-ray shower. The best material to shield against these cosmic-ray components is iron, which has the best combination of primary shielding and minimal secondary neutron production.

Aguayo Navarrete, Estanislao; Kouzes, Richard T.; Ankney, Austin S.; Orrell, John L.; Berguson, Timothy J.; Troy, Meredith D.

2011-09-08

311

VIEW OF BUILDING 440 LOOKING WEST, NORTHWEST. BUILDING 440, THE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

VIEW OF BUILDING 440 LOOKING WEST, NORTHWEST. BUILDING 440, THE TRANSPORT MODIFICATION CENTER, CONSISTS OF FOUR HIGH-BAY CORRUGATED METAL STRUCTURES. BUILDING 440 WAS USED FOR PACKAGING AND STAGING SPECIAL NUCLEAR MATERIALS AND DEPLETED URANIUM FOR SHIPMENT AND TO MODIFY VEHICLES TO MEET SPECIFIC UNITED STATES DEPARTMENT OF ENERGY REQUIREMENTS. (2/8/84) - Rocky Flats Plant, Transport Modification Center, North of Cactus Avenue, approximately 400 feet east of Third Street, Golden, Jefferson County, CO

312

ETR HEAT EXCHANGER BUILDING, TRA644. A PRIMARY COOLANT PUMP AND ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

ETR HEAT EXCHANGER BUILDING, TRA-644. A PRIMARY COOLANT PUMP AND 24-INCH CHECK VALVE ARE MOUNTED IN A SHIELDED CUBICLE. NOTE CONNECTION AT RIGHT THROUGH SHIELD WALL TO PUMP MOTOR ON OTHER SIDE. INL NEGATIVE NO. 56-4177. Jack L. Anderson, Photographer, 12/21/1956 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

313

Building the Best Auditorium  

ERIC Educational Resources Information Center

Building a quality auditorium has never come at a cheap price. In today's economy, a $750,000 minimum price tag just for sound, lighting, stage rigging and seats can be exorbitant. However, schools that have built new auditoriums or upgraded existing ones in the past decade say the investment is worth every penny. This article discusses the…

Sturgeon, Julie

2008-01-01

314

A heated stage and tissue culture chamber for electrophysiology.  

PubMed

A simple, inexpensive heating circuit is described for use with a warmed microscope stage, small tissue bath, and heated tissue culture chamber. A major consideration in the design of the apparatus is a compatability with electrophysiological studies. Thus, proper shielding and low profile for microelectrode positioning are featured. PMID:1021472

Bonkowski, L; Runion, H I

1976-12-15

315

BUILDING INSPECTION Building, Infrastructure, Transportation  

E-print Network

BUILDING INSPECTION Building, Infrastructure, Transportation City of Redwood City 1017 Middlefield Sacramento, Ca 95814-5514 Re: Green Building Ordinance and the Building Energy Efficiency Standards Per of Redwood City enforce the current Title 24 Building Energy Efficiency Standards as part

316

The influence of radiation shielding on reusable nuclear shuttle design  

NASA Technical Reports Server (NTRS)

Alternate reusable nuclear shuttle configurations were synthesized and evaluated. Particular attention was given to design factors which reduced tank exposure to direct and scattered radiation, increased payload-engine separation, and improved self-shielding by the LH2 propellant. The most attractive RNS concept in terms of cost effectiveness consists of a single conical aft bulkhead tank with a high fineness ratio. Launch is accomplished by the INT-21 with the tank positioned in the inverted attitude. The NERVA engine is delivered to orbit separately where final stage assembly and checkout are accomplished. This approach is consistent with NERVA definition criteria and required operating procedures to support an economically viable nuclear shuttle transportation program in the post-1980 period.

Littman, T. M.; Garcia, D.

1972-01-01

317

Reactor and shielding design implications of clustering nuclear thermal rockets  

NASA Astrophysics Data System (ADS)

This paper examines design considerations in the context of engine-out accidents in clustered nuclear-thermal rocket stages, and an accident-management protocol is devised. Safety and performance issues are considered in the light of designs for the reactor and shielding elements of ROVER/NERVA-type engines. The engine-out management process involves: phase one, in which sufficient propulsive power is guaranteed for mission completion; and phase two, in which engine failure is isolated and not allowed to propagate to other engines or to the spacecraft. Phase-one designs can employ spare engines, throttled engines, and/or long-burning engines. Phase-two safety concepts can include techniques for cooling or jettisoning the failed engines. Engine-out management philosophies are shown to be shaped by a combination of safety and mission-trajectory requirements.

Buksa, John J.; Houts, Michael G.

1992-07-01

318

Reactor and shielding design implications of clustering nuclear thermal rockets  

SciTech Connect

This paper examines design considerations in the context of engine-out accidents in clustered nuclear-thermal rocket stages, and an accident-management protocol is devised. Safety and performance issues are considered in the light of designs for the reactor and shielding elements of ROVER/NERVA-type engines. The engine-out management process involves: phase one, in which sufficient propulsive power is guaranteed for mission completion; and phase two, in which engine failure is isolated and not allowed to propagate to other engines or to the spacecraft. Phase-one designs can employ spare engines, throttled engines, and/or long-burning engines. Phase-two safety concepts can include techniques for cooling or jettisoning the failed engines. Engine-out management philosophies are shown to be shaped by a combination of safety and mission-trajectory requirements. 6 refs.

Buksa, J.J.; Houts, M.G. (Los Alamos National Laboratory, NM (United States))

1992-07-01

319

Intercalated graphite fiber composites as EMI shields in aerospace structures  

NASA Technical Reports Server (NTRS)

The requirements for electromagnetic interference (EMI) shielding in aerospace structures are complicated over that of ground structures by their weight limitations. As a result, the best EMI shielding materials must blend low density, high strength, and high elastic modulus with high shielding ability. In addition, fabrication considerations including penetrations and joints play a major role. The EMI shielding properties are calculated for shields formed from pristine and intercalated graphite fiber/epoxy composites and compared to preliminary experimental results and to shields made from aluminum. Calculations indicate that EMI shields could be fabricated from intercalated graphite composites which would have less than 12 percent of the mass of conventional aluminum shields, based on mechanical properties and shielding properties alone.

Gaier, James R.

1990-01-01

320

Simulating Building Fires for Movies  

NASA Technical Reports Server (NTRS)

Fire scenes for cinematography staged at relatively low cost in method that combines several existing techniques. Nearly realistic scenes, suitable for firefighter training, produced with little specialized equipment. Sequences of scenes set up quickly and easily, without compromising safety because model not burned. Images of fire, steam, and smoke superimposed on image of building to simulate burning of building.

Rodriguez, Ricardo C.; Johnson, Randall P.

1987-01-01

321

Postshield stage transitional volcanism on Mahukona Volcano, Hawaii  

Microsoft Academic Search

Age spectra from 40Ar\\/39Ar incremental heating experiments yield ages of 298?±?25 ka and 310?±?31 ka for transitional composition lavas from two cones\\u000a on submarine Mahukona Volcano, Hawaii. These ages are younger than the inferred end of the tholeiitic shield stage and indicate\\u000a that the volcano had entered the postshield alkalic stage before going extinct. Previously reported elevated helium isotopic\\u000a ratios of lavas

David A. Clague; Andrew T. Calvert

2009-01-01

322

Design and Development of an In-Space Deployable Sun Shield for the Atlas Centaur  

NASA Technical Reports Server (NTRS)

The Centaur, by virtue of its use of high specific-impulse (Isp) LO2/LH2 propellants, has initial mass-to-orbit launch requirements less than half of those upper stages using storable propellants. That is, for Earth escape or GSO missions the Centaur is half the launch weight of a storable propellant upper stage. A drawback to the use of Liquid oxygen and liquid hydrogen, at 90 K and 20 K respectively, over storable propellants is the necessity of efficient cryogen storage techniques that minimize boil-off from thermal radiation in space. Thermal blankets have been used successfully to shield both the Atlas Centaur and Titan Centaur. These blankets are protected from atmospheric air loads during launch by virtue of the fact that the Centaur is enclosed within the payload fairing. The smaller Atlas V vehicle, the Atlas 400, has the Centaur exposed to the atmosphere during launch, and therefore, to date has not flown with thermal blankets shielding the Centaur. A design and development effort is underway to fly a thermal shield on the Atlas V 400 vehicle that is not put in place until after the payload fairing jettisons. This can be accomplished by the use of an inflatable and deployable thermal blanket referred to as the Centaur Sun Shield (CSS). The CSS design is also scalable for use on a Delta upper stage, and the technology potentially could be used for telescope shades, re-entry shields, solar sails and propellant depots. A Phase I effort took place during 2007 in a partnership between ULA and ILC Dover which resulted in a deployable proof-of-concept Sun Shield being demonstrated at a test facility in Denver. A Phase H effort is underway during 2008 with a partnership between ULA, ILC, NASA Glenn Research Center (GRC) and NASA Kennedy Space Center (KSC) to define requirements, determine materials and fabrication techniques, and to test components in a vacuum chamber at cold temperatures. This paper describes the Sun Shield development work to date, and the future plans leading up to a flight test in the 2011 time frame.

Dew, Michael; Allwein, Kirk; Kutter, Bernard; Ware, Joanne; Lin, John; Madlangbayan, Albert; Willey, Cliff; Pitchford, Brian; O'Neil, Gary

2008-01-01

323

Radiation shielding effectiveness of newly developed superconductors  

NASA Astrophysics Data System (ADS)

Gamma ray shielding effectiveness of superconductors with a high mass density has been investigated. We calculated the mass attenuation coefficients, the mean free path (mfp) and the exposure buildup factor (EBF). The gamma ray EBF was computed using the Geometric Progression (G-P) fitting method at energies 0.015-15 MeV, and for penetration depths up to 40 mfp. The fast-neutron shielding effectiveness has been characterized by the effective neutron removal cross-section of the superconductors. It is shown that CaPtSi3, CaIrSi3, and Bi2Sr2Ca1Cu2O8.2 are superior shielding materials for gamma rays and Tl0.6Rb0.4Fe1.67Se2 for fast neutrons. The present work should be useful in various applications of superconductors in fusion engineering and design.

Singh, Vishwanath P.; Medhat, M. E.; Badiger, N. M.; Saliqur Rahman, Abu Zayed Mohammad

2015-01-01

324

Overview of SNS accelerator shielding analyses  

SciTech Connect

The Spallation Neutron Source is an accelerator driven neutron scattering facility for materials research. During all phases of SNS development, including design, construction, commissioning and operation, extensive neutronics work was performed in order to provide adequate shielding, to assure safe facility operation from radiation protection point of view, and to optimize performance of the accelerator and target facility. Presently, most of the shielding work is concentrated on the beam lines and instrument enclosures to prepare for commissioning, safe operation and adequate radiation background in the future. Although the accelerator is built and in operation mode, there is extensive demand for shielding and activation analyses. It includes redesigning some parts of the facility, facility upgrades, designing additional structures, storage and transport containers for accelerator structures taken out of service, and performing radiation protection analyses and studies on residual dose rates inside the accelerator. (authors)

Popova, I.; Gallmeier, F. X.; Ferguson, P.; Iverson, E.; Lu, W. [ORNL/SNS, MS6475, PO Box 2008, Oak Ridge, TN 37831-6471 (United States)

2012-07-01

325

Vehicle drive module having improved EMI shielding  

DOEpatents

EMI shielding in an electric vehicle drive is provided for power electronics circuits and the like via a direct-mount reference plane support and shielding structure. The thermal support may receive one or more power electronic circuits. The support may aid in removing heat from the circuits through fluid circulating through the support. The support forms a shield from both external EMI/RFI and from interference generated by operation of the power electronic circuits. Features may be provided to permit and enhance connection of the circuitry to external circuitry, such as improved terminal configurations. Modular units may be assembled that may be coupled to electronic circuitry via plug-in arrangements or through interface with a backplane or similar mounting and interconnecting structures.

Beihoff, Bruce C.; Kehl, Dennis L.; Gettelfinger, Lee A.; Kaishian, Steven C.; Phillips, Mark G.; Radosevich, Lawrence D.

2006-11-28

326

Power converter having improved EMI shielding  

DOEpatents

EMI shielding is provided for power electronics circuits and the like via a direct-mount reference plane support and shielding structure. The thermal support may receive one or more power electronic circuits. The support may aid in removing heat from the circuits through fluid circulating through the support. The support forms a shield from both external EMI/RFI and from interference generated by operation of the power electronic circuits. Features may be provided to permit and enhance connection of the circuitry to external circuitry, such as improved terminal configurations. Modular units may be assembled that may be coupled to electronic circuitry via plug-in arrangements or through interface with a backplane or similar mounting and interconnecting structures.

Beihoff, Bruce C.; Kehl, Dennis L.; Gettelfinger, Lee A.; Kaishian, Steven C.; Phillips, Mark G.; Radosevich, Lawrence D.

2006-06-13

327

Electronics Shielding and Reliability Design Tools  

NASA Technical Reports Server (NTRS)

It is well known that electronics placement in large-scale human-rated systems provides opportunity to optimize electronics shielding through materials choice and geometric arrangement. For example, several hundred single event upsets (SEUs) occur within the Shuttle avionic computers during a typical mission. An order of magnitude larger SEU rate would occur without careful placement in the Shuttle design. These results used basic physics models (linear energy transfer (LET), track structure, Auger recombination) combined with limited SEU cross section measurements allowing accurate evaluation of target fragment contributions to Shuttle avionics memory upsets. Electronics shielding design on human-rated systems provides opportunity to minimize radiation impact on critical and non-critical electronic systems. Implementation of shielding design tools requires adequate methods for evaluation of design layouts, guiding qualification testing, and an adequate follow-up on final design evaluation including results from a systems/device testing program tailored to meet design requirements.

Wilson, John W.; ONeill, P. M.; Zang, Thomas A., Jr.; Pandolf, John E.; Koontz, Steven L.; Boeder, P.; Reddell, B.; Pankop, C.

2006-01-01

328

Phenomenological calculations of shielding spallation neutron sources  

NASA Astrophysics Data System (ADS)

The high level of radiation generated by a spallation source requires the design of an appropriate shielding to surround the source in order to fulfill radiation protection standards. A calculation of the spallation neutron attenuation is presented for various shielding materials, using a phenomenological model, based on the Moyer model. In the first step of the calculation, the interaction length of neutrons for each neutron energy and shielding material was estimated using inelastic cross-sections. In the second step the calculation deals with the attenuation of the neutron flux applying the Moyer model, for each material and neutron energy region. The transmission factors were calculated and compared with experimental data collected from the "Gamma-2" and the "E+T" projects running in JINR (Dubna, Russia). The results of the present work were also compared to the data obtained by different Monte Carlo codes such as MORSE, MCNPX, MARS14 and LAHET.

Fragopoulou, M.; Zamani, M.

2013-06-01

329

Vehicle Shield Optimization and Risk Assessment for Future Human Space Missions  

NASA Technical Reports Server (NTRS)

As the focus of future human space missions shifts to destinations beyond low Earth orbit such as Near Earth Objects (NEO), the moon, or Mars, risks associated with extended stay in hostile radiation environment need to be well understood and assessed. Since future spacecrafts designs and shapes are evolving continuous assessments of shielding and radiation risks are needed. In this study, we use a predictive software capability that calculates risks to humans inside a spacecraft prototype that builds on previous designs. The software uses CAD software Pro/Engineer and Fishbowl tool kit to quantify radiation shielding provided by the spacecraft geometry by calculating the areal density seen at a certain point, dose point, inside the spacecraft. Shielding results are used by NASA-developed software, BRYNTRN, to quantify organ doses received in a human body located in the vehicle in case of solar particle event (SPE) during such prolonged space missions. Organ doses are used to quantify risks on astronauts health and life using NASA Space Cancer Model. The software can also locate shielding weak points-hotspots-on the spacecraft s outer surface. This capability is used to reinforce weak areas in the design. Results of shielding optimization and risk calculation on an exploration vehicle design for missions of 6 months and 30 months are provided in this study. Vehicle capsule is made of aluminum shell that includes main cabin and airlock. The capsule contains 5 sets of racks that surround working and living areas. Water shelter is provided in the main cabin of the vehicle to enhance shielding in case of SPE.

Nounu, Hatem N.; Kim, Myung-Hee; Cucinotta, Francis A.

2011-01-01

330

Static Structural Analysis for a Neutron Shielding Block in ITER  

NASA Astrophysics Data System (ADS)

The ITER neutron shielding blocks are located between the outer shell and the inner shell of the vacuum vessel to provide neutron shielding. Considering the combined loads acting on the shielding blocks during ITER plasma operation, the structure of the shielding blocks must be evaluated. Using the finite element method with ANSYS analysis software, static structural analysis is performed, including elastic analysis and limit analysis for one typical shielding block. The evaluated results based on RCC-MR code show that the structure of this shielding block can meet the design requirement.

Hao, Junchuan; Song, Yuntao; Wang, Xiaoyu; Ioki, K.; Du, Shuangsong; Ji, Xiang; Feng, Changle; Xu, Yang

2013-02-01

331

Scale-PC shielding analysis sequences  

SciTech Connect

The SCALE computational system is a modular code system for analyses of nuclear fuel facility and package designs. With the release of SCALE-PC Version 4.3, the radiation shielding analysis community now has the capability to execute the SCALE shielding analysis sequences contained in the control modules SAS1, SAS2, SAS3, and SAS4 on a MS- DOS personal computer (PC). In addition, SCALE-PC includes two new sequences, QADS and ORIGEN-ARP. The capabilities of each sequence are presented, along with example applications.

Bowman, S.M.

1996-05-01

332

Prototype V-Groove Radiator Heat Shield  

NASA Technical Reports Server (NTRS)

Report describes design, fabrication, and testing of heat radiator equipped with multi-V-groove radiator heat shield. Device compact, efficient structure which removes heat from infrared detectors, gamma-ray detectors, and similar instruments aboard Mars Observer spacecraft and radiates heat into outer space. Designed to maintain detector for gamma-ray spectrometer at temperature of 80 K in cold vacuum under heat load of 80 mW. Prototype made of aluminum, though production shields made of aluminized sheets of polyethylene terephthalate.

Petrick, S. Walter; Bard, Steven

1990-01-01

333

Hysteresis prediction inside magnetic shields and application.  

PubMed

We have developed a simple model that is able to describe and predict hysteresis behavior inside Mumetal magnetic shields, when the shields are submitted to ultra-low frequency (<0.01 Hz) magnetic perturbations with amplitudes lower than 60??T. This predictive model has been implemented in a software to perform an active compensation system. With this compensation the attenuation of longitudinal magnetic fields is increased by two orders of magnitude. The system is now integrated in the cold atom space clock called PHARAO. The clock will fly onboard the International Space Station in the frame of the ACES space mission. PMID:25085183

Mori?, Igor; De Graeve, Charles-Marie; Grosjean, Olivier; Laurent, Philippe

2014-07-01

334

Hysteresis prediction inside magnetic shields and application  

SciTech Connect

We have developed a simple model that is able to describe and predict hysteresis behavior inside Mumetal magnetic shields, when the shields are submitted to ultra-low frequency (<0.01 Hz) magnetic perturbations with amplitudes lower than 60??T. This predictive model has been implemented in a software to perform an active compensation system. With this compensation the attenuation of longitudinal magnetic fields is increased by two orders of magnitude. The system is now integrated in the cold atom space clock called PHARAO. The clock will fly onboard the International Space Station in the frame of the ACES space mission.

Mori?, Igor [Observatoire de Paris, SYRTE, Avenue Denfert 77, 75014 Paris (France); CNES, Edouard Belin 18, 31400 Toulouse (France); De Graeve, Charles-Marie [SOGETI High Tech, chemin Laporte 3, 31300 Toulouse (France); Grosjean, Olivier [CNES, Edouard Belin 18, 31400 Toulouse (France); Laurent, Philippe [Observatoire de Paris, SYRTE, Avenue Denfert 77, 75014 Paris (France)

2014-07-15

335

Hysteresis prediction inside magnetic shields and application  

NASA Astrophysics Data System (ADS)

We have developed a simple model that is able to describe and predict hysteresis behavior inside Mumetal magnetic shields, when the shields are submitted to ultra-low frequency (<0.01 Hz) magnetic perturbations with amplitudes lower than 60 ?T. This predictive model has been implemented in a software to perform an active compensation system. With this compensation the attenuation of longitudinal magnetic fields is increased by two orders of magnitude. The system is now integrated in the cold atom space clock called PHARAO. The clock will fly onboard the International Space Station in the frame of the ACES space mission.

Mori?, Igor; De Graeve, Charles-Marie; Grosjean, Olivier; Laurent, Philippe

2014-07-01

336

Blue Cross and Blue Shield of Alabama  

NSDL National Science Digital Library

The Alabama BlueCross and BlueShield Medical Information Server, located and developed by the University of Alabama at Birmingham Department of Computer and Information Sciences, through a grant from Blue Cross and Blue Shield of Alabama for the express purpose of providing Internet access to medical information for all physicians and other health care providers in the state of Alabama. It provides links to a broad range of medical information resources located throughout the Internet. Menus provide information on diseases and disorders, patient care and medical practice, medical specialties, journals and newsletters, health care reform, and other medical information.

337

Tectonic evolution of the Western Australian Shield  

NASA Technical Reports Server (NTRS)

Geological and geochronological studies in the Western Australian Shield were updated. This terrane bears many similarities to the Indian Shield since they were neighboring parts of Gondwanaland. Western Australia consists of two cratons (Pilbara and Yilgarn) and four orogenic belts (Capricorn, Pingarra, Albany-Fraser, and Patterson), as well as some relatively young (1.6 to 0.75 Ga) sedimentary rocks. The two cratonic blocks are both older than about 2.5 Ga, and the orogenic belts range in age from 2.0 to 0.65 Ga.

Myers, John S.

1988-01-01

338

Building Green  

NSDL National Science Digital Library

Information designed to help building industry professionals and policy makers to improve environmental performance and reduce the adverse impacts of buildings. Offers print and electronic resources to help industry professionals to take an integrated design approach that will minimize ecological impact and maximize economic performance. The publications related to green building include Environmental Building News - a monthly newsletter that is independently published and advertising-free; The GreenSpec Product Directory; and Green Building Advisor.

339

Understanding space weather to shield society  

E-print Network

Understanding space weather to shield society Improving understanding and forecasts of space weather requires addressing scientific challenges within the network of physical processes that connect the Sun to society. The roadmap team identified the highest-priority areas within the Sun-Earth space-weather

Schrijver, Karel

340

SCALE radiation shielding V and V package  

SciTech Connect

Verification and validation (V and V) are essential elements of software quality assurance (QA) for computer codes that are used for scientific calculations. The sponsors of the SCALE code system have required a QA plan and a V and V plan. For purposes of validating and verifying the SCALE shielding codes, a set of problems has been assembled and tested.

Emmett, M.B.; Bowman, S.M.; Broadhead, B.L.

1997-12-01

341

Reflectivity level of RF shielded anechoic chamber  

Microsoft Academic Search

The reflectivity level of an RF shielded rectangular chamber with a non-uniform absorber lining has been investigated using the geometrical optics approach. The excitation antennas considered are the Hertzian dipole, a halfwave dipole and a pyramidal horn. A simple model is employed for the reflectivity of the absorber lining for normal incidence

S. V. K. Shastry; S. K. Nagesh; D. Binu

1995-01-01

342

Internally shielded beam transport and support system  

SciTech Connect

Due to environmental concerns, the Advanced Photon Source has a policy that disallows any exposed lead within the facility. This creates a real problem for the beam transport system, not so much for the pipe but for the flexible coupling (bellows) sections. A complete internally shielded x-ray transport system, consisting of long transport lines joined by flexible coupling sections, has been designed for CARS sector 14 to operate either at high vacuum or as a helium flight tube. It can effectively shield against air scattering of wiggler or undulator white beam with proper placement of apertures, collimators, and masks for direct beam control. The system makes use of male- and female-style fittings that create a labyrinth allowing for continuous shielding through the flexible coupling sections. These parts are precision machined from a ternary hypereutectic lead alloy (cast under 15 inches of head pressure to assure a pinhole-free casting) then pressed into either end (rotatable vacuum flanges) of the bellows assembly. The transport pipe itself consists of a four part construction using a stepped transition ring (Z-ring) to connect an inner tube to the vacuum flange and also to a protective and supportive outer tube. The inner tube is wrapped with 1/16{double_prime} pure lead sheet to a predetermined thickness following the shape of the stepped transition ring for continuous shielding. This design has been prototyped and radiation tested. {copyright} {ital 1996 American Institute of Physics.}

Schildkamp, W.; Brewer, H. [Consortium for Advanced Radiation Sources, University of Chicago, 5640 S. Ellis Ave., Chicago, IL 60637 (United States)] [Consortium for Advanced Radiation Sources, University of Chicago, 5640 S. Ellis Ave., Chicago, IL 60637 (United States)

1996-09-01

343

Lunar soil as shielding against space radiation  

Microsoft Academic Search

We have measured the radiation transport and dose reduction properties of lunar soil with respect to selected heavy ion beams with charges and energies comparable to some components of the galactic cosmic radiation (GCR), using soil samples returned by the Apollo missions and several types of synthetic soil glasses and lunar soil simulants. The suitability for shielding studies of synthetic

J. Miller; L. Taylor; C. Zeitlin; L. Heilbronn; S. Guetersloh; M. DiGiuseppe; Y. Iwata; T. Murakami

2009-01-01

344

Ford Motor Company NDE facility shielding design.  

PubMed

Ford Motor Company proposed the construction of a large non-destructive evaluation laboratory for radiography of automotive power train components. The authors were commissioned to design the shielding and to survey the completed facility for compliance with radiation doses for occupationally and non-occupationally exposed personnel. The two X-ray sources are Varian Linatron 3000 accelerators operating at 9-11 MV. One performs computed tomography of automotive transmissions, while the other does real-time radiography of operating engines and transmissions. The shield thickness for the primary barrier and all secondary barriers were determined by point-kernel techniques. Point-kernel techniques did not work well for skyshine calculations and locations where multiple sources (e.g. tube head leakage and various scatter fields) impacted doses. Shielding for these areas was determined using transport calculations. A number of MCNP [Briesmeister, J. F. MCNPCA general Monte Carlo N-particle transport code version 4B. Los Alamos National Laboratory Manual (1997)] calculations focused on skyshine estimates and the office areas. Measurements on the operational facility confirmed the shielding calculations. PMID:16604635

Metzger, Robert L; Van Riper, Kenneth A; Jones, Martin H

2005-01-01

345

Martian regolith as space radiation shielding.  

PubMed

In current Mars scenario descriptions, an entire mission is estimated to take 500-1000 days round trip with a 100-600 day stay time on the surface. To maintain radiation dose levels below permissible limits, dose estimates must be determined for the entire mission length. With extended crew durations anticipated on Mars, the characterization of the radiation environment on the surface becomes a critical aspect of mission planning. The most harmful free-space radiation is due to high energy galactic cosmic rays (GCR) and solar flare protons. The carbon dioxide atmosphere of Mars has been estimated to provide a sufficient amount of shielding from these radiative fluxes to help maintain incurred doses below permissible limits. However, Mars exploration crews are likely to incur a substantial dose while in transit to Mars that will reduce the allowable dose that can be received while on the surface. Therefore, additional shielding may be necessary to maintain short-term dose levels below limits or to help maintain career dose levels as low as possible. By utilizing local resources, such as Martian regolith, shielding materials can be provided without excessive launch weight requirements from Earth. The scope of this synopsis and of Ref. 3 focuses on presenting our estimates of surface radiation doses received due to the transport and attenuation of galactic cosmic rays and February 1956 solar flare protons through the Martian atmosphere and through additional shielding provided by Martian regolith. PMID:11537624

Simonsen, L C; Nealy, J E; Townsend, L W; Wilson, J W

1991-01-01

346

The calculation of radiation and shielding  

Microsoft Academic Search

In order to facilitate the rapid and accurate computation of radiation intensities from various materials exposed in a nuclear reactor and of the shielding required by these materials, the attached tables and graphs have been assembled from current information for routine use. It was necessary in some cases to assume a decay scheme where the scheme was not known, but

Nather

1951-01-01

347

Oxygen Abundance Measurements of SHIELD Galaxies  

E-print Network

We have derived oxygen abundances for 8 galaxies from the Survey of HI in Extremely Low-mass Dwarfs (SHIELD). The SHIELD survey is an ongoing study of very low-mass galaxies, with M$_{\\rm HI}$ between 10$^{6.5}$ and 10$^{7.5}$ M$_{\\odot}$, that were detected by the Arecibo Legacy Fast ALFA (ALFALFA) survey. H$\\alpha$ images from the WIYN 3.5m telescope show that these 8 SHIELD galaxies each possess one or two active star-forming regions which were targeted with long-slit spectral observations using the Mayall 4m telescope at KPNO. We obtained a direct measurement of the electron temperature by detection of the weak [O III] $\\lambda$4363 line in 2 of the HII regions. Oxygen abundances for the other HII regions were estimated using a strong-line method. When the SHIELD galaxies are plotted on a B-band luminosity-metallicity diagram they appear to suggest a slightly shallower slope to the relationship than normally seen. However, that offset is systematically reduced when the near-infrared luminosity is used ins...

Haurberg, Nathalie C; Cannon, John M; Marshall, Melissa V

2015-01-01

348

New shield for gamma-ray spectrometry  

NASA Technical Reports Server (NTRS)

Gamma-ray shield that can be evacuated, refilled with a clean gas, and pressurized for exclusion of airborne radioactive contaminants effectively lowers background noise. Under working conditions, repeated evacuation and filling procedures have not adversely affected the sensitivity and resolution of the crystal detector.

Brar, S. S.; Gustafson, P. F.; Nelson, D. M.

1969-01-01

349

The Radiation Shielding Competition Sponsored by  

E-print Network

variations of shield material. Hint: Elements with a high atomic number block gamma rays best (but watch of radiation. These can be in the form of particles (alpha, beta, etc.) or in the form of photons (gamma rays. In this competition, we consider gamma radiation from a laboratory source. Gamma rays are high energy photons speeding

Wang, Xiaorui "Ray"

350

Oxygen Abundance Measurements of SHIELD Galaxies  

NASA Astrophysics Data System (ADS)

We have derived oxygen abundances for eight galaxies from the Survey for H I in Extremely Low-mass Dwarfs (SHIELD). The SHIELD survey is an ongoing study of very-low-mass galaxies, with MH \\scriptsize{I} between 106.5 and 107.5 M ?, that were detected by the Arecibo Legacy Fast ALFA survey. H? images from the WIYN 3.5 m telescope show that these eight SHIELD galaxies each possess one or two active star-forming regions, which were targeted with long-slit spectral observations using the Mayall 4 m telescope at Kitt Peak National Observatory. We obtained a direct measurement of the electron temperature by detection of the weak [O III] ?4363 line in two of the H II regions. Oxygen abundances for the other H II regions were estimated using a strong-line method. When the SHIELD galaxies are plotted on a B-band L-Z diagram, they appear to suggest a slightly shallower slope to the relationship than normally seen. However, that offset is systematically reduced when the near-infrared luminosity is used instead. This indicates a different mass-to-light ratio for the galaxies in this sample and we suggest that this may be indicative of differing star formation histories in the lowest luminosity and surface brightness dwarf irregulars.

Haurberg, Nathalie C.; Salzer, John J.; Cannon, John M.; Marshall, Melissa V.

2015-02-01

351

Cheaper Custom Shielding Cups For Arc Welding  

NASA Technical Reports Server (NTRS)

New way of making special-purpose shielding cups for gas/tungsten arc welding from hobby ceramic greatly reduces cost. Pattern machined in plastic. Plaster-of-paris mold made, and liquid ceramic poured into mold. Cost 90 percent less than cup machined from lava rock.

Morgan, Gene E.

1992-01-01

352

Fusion reactor blanket\\/shield design study  

Microsoft Academic Search

A joint study of Tokamak reactor first wall\\/blanket\\/shield technology was conducted to identify key technological limitations for various tritium breeding blanket design concepts, establishment of a basis for assessment and comparison of the design features of each concept, and development of optimized blanket designs. The approach used involved a review of previously proposed blanket designs, analysis of critical technological problems

D. L. Smith; R. G. Clemmer; S. D. Harkness; J. Jung; J. L. Krazinski; R. F. Mattas; H. C. Stevens; C. K. Youngdahl; C. Trachsel; D. Bowers

1979-01-01

353

The Tower Shielding Facility: Its glorious past  

SciTech Connect

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.

Muckenthaler, F.J.

1997-05-07

354

Passive magnetic shielding in static gradient fields  

NASA Astrophysics Data System (ADS)

The effect of passive magnetic shielding on dc magnetic field gradients imposed by both external and internal sources is studied for two idealized shield models: concentric spherical and infinitely-long cylindrical shells of linear material. It is found that higher-order multipoles of an externally applied magnetic field are always shielded progressively better for either geometry by a factor related to the order of the multipole. In regard to the design of internal coil systems, we determine reaction factors for the general multipole field and provide examples of how one can take advantage of the coupling of the coils to the innermost shell to optimize the uniformity of the field. Furthermore, we provide formulae relevant to active magnetic compensation systems which attempt to stabilize the interior fields by sensing and cancelling the exterior fields close to the outermost shell. Overall this work provides a comprehensive framework that is useful for the analysis and optimization of dc magnetic shields, serving as a theoretical and conceptual design guide as well as a starting point and benchmark for finite-element analysis.

Bidinosti, C. P.; Martin, J. W.

2014-04-01

355

Ram side of Wake Shield Facility  

NASA Technical Reports Server (NTRS)

The ram side of the Wake Shield Facility (WSF) is in the grasp of the Space Shuttle Discovery's Remote Manipulator System (RMS) arm in this 70mm frame. Clouds over the Atlantic Ocean and the blackness of space share the backdrop for the picture.

1994-01-01

356

Multi-Shielded p-FET Dosimeter  

NASA Technical Reports Server (NTRS)

A compact device was developed for dose measurements where each of four p-FETs has a different shield. Radiation data from the STRV-1b shows that p-FETs can be used to map the radiation inside a spacecraft.

Buehler, M.; Blaes, B.; Martin, D.; Bowman, C.; Bogorad, A.

1995-01-01

357

Early test facilities and analytic methods for radiation shielding: Proceedings  

SciTech Connect

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.

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

1992-11-01

358

30 CFR 57.14213 - Ventilation and shielding for welding.  

Code of Federal Regulations, 2010 CFR

...14213 Ventilation and shielding for 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...

2010-07-01

359

30 CFR 56.14213 - Ventilation and shielding for welding.  

Code of Federal Regulations, 2010 CFR

...14213 Ventilation and shielding for 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...

2010-07-01

360

EMI SHIELDING TEST METHOD FOR SMALL WIRELESS DEVICES  

Microsoft Academic Search

We introduce a new cavity-to-cavity isolation standard for measuring the electric field attenuation of EMI\\/RFI shielding systems used in small wireless devices. The test specimen, which represents the shielding system under evaluation, is a \\

Robert Foster; David Rich

361

Impact damage on shielded gas-filled vessels  

NASA Astrophysics Data System (ADS)

This paper gives a summary of the findings from impacts on shielded gas-filled cylindrical aluminium alloy (A12219 T851) and titanium alloy (Ti6A14V) pressure vessels that were performed at the Ernst-Mach-Institute in the frame of an ESA contract. The effect of impacts on shielded vessels with projectiles that have a kinetic energy close to the ballistic limit of the combined system of shield and vessel's front wall was investigated. The shields were single Al-bumper plates, unreinforced MLI and MLI reinforced with 2 layers of Betacloth. The threshold diameters that cause leakage from the vessel's front wall were determined experimentally as a function of shield material and shield spacing. For Al-shielded Al- and Ti-vessels, a safety design factor to avoid leakage is presented based on existing Whipple shield equations.

Schäfer, F.; Schneider, E.; Lambert, M.

2001-10-01

362

Composite Structures Materials Testing for the Orion Crew Vehicle Heat Shield  

NASA Technical Reports Server (NTRS)

As research is being performed for the new heat shield for the Orion capsule, National Aeronautics and Space Administration (NASA) is developing the first composite heat shield. As an intern of the Structures Branch in the Engineering Directorate (ES 2), my main task was to set up a test plan to determine the material properties of the honeycomb that will be used on the Orion Crew Module heat shield to verify that the composite is suitable for the capsule. Before conducting composite shell tests, which are performed to simulate the crush performance of the heat shield on the capsule, it is necessary to determine the compression and shear properties of the composite used on the shell. During this internship, I was responsible for developing a test plan, designing parts for the test fixtures as well as getting them fabricated for the honeycomb shear and compression testing. This involved work in Pro/Engineer as well as coordinating with Fab Express, the Building 9 Composite Shop and the Structures Test Laboratory (STL). The research and work executed for this project will be used for composite sandwich panel testing in the future as well. As a part of the Structures Branch, my main focus was to research composite structures. This involves system engineering and integration (SE&I) integration, manufacturing, and preliminary testing. The procedures for these projects that were executed during this internship included design work, conducting tests and performing analysis.

Khemani, Farah N.

2011-01-01

363

Stages of Anal Cancer  

MedlinePLUS

Stages of Anal Cancer Key Points for This Section After anal cancer has been diagnosed, tests are done to find out ... II Stage IIIA Stage IIIB Stage IV After anal cancer has been diagnosed, tests are done to ...

364

Stages of Pancreatic Cancer  

MedlinePLUS

Stages of Pancreatic Cancer Key Points for This Section Tests and procedures to stage pancreatic cancer are usually done at the same ... III Stage IV Tests and procedures to stage pancreatic cancer are usually done at the same time as ...

365

Stages of Esophageal Cancer  

MedlinePLUS

... cancer cells. The following stages are used for squamous cell carcinoma of the esophagus: Stage 0 (High-grade Dysplasia) ... is also called high-grade dysplasia. Stage I squamous cell carcinoma of the esophagus Stage I is divided into ...

366

High-Flux, High-Temperature Thermal Vacuum Qualification Testing of a Solar Receiver Aperture Shield  

NASA Technical Reports Server (NTRS)

As part of the International Space Station (ISS) Phase 1 program, NASA Lewis Research Center (LERC) and the Russian Space Agency (RSA) teamed together to design, build and flight test the world's first orbital Solar Dynamic Power System (SDPS) on the Russian space station Mir. The Solar Dynamic Flight Demonstration (SDFD) program was to operate a nominal 2 kWe SDPS on Mir for a period up to 1-year starting in late 1997. Unfortunately, the SDFD mission was demanifested from the ISS phase 1 shuttle program in early 1996. However, substantial flight hardware and prototypical flight hardware was built including a heat receiver and aperture shield. The aperture shield comprises the front face of the cylindrical cavity heat receiver and is located at the focal plane of the solar concentrator. It is constructed of a stainless steel plate with a 1-m outside diameter, a 0.24-m inside diameter and covered with high-temperature, refractory metal Multi-Foil Insulation (MFI). The aperture shield must minimize heat loss from the receiver cavity, provide a stiff, high strength structure to accommodate shuttle launch loads and protect receiver structures from highly concentrated solar fluxes during concentrator off-pointing events. To satisfy Mir operational safety protocols, the aperture shield was required to accommodate direct impingement of the intensely concentrated solar image for a 1-hour period. To verify thermal-structural durability under the anticipated high-flux, high-temperature loading, an aperture shield test article was constructed and underwent a series of two tests in a large thermal vacuum chamber configured with a reflective, point-focus solar concentrator and a solar simulator. The test article was positioned near the focal plane and exposed to concentrated solar flux for a period of 1-hour. In the first test, a near equilibrium temperature of 1862 K was attained in the center of the shield hot spot. In the second test, with increased incident flux, a near equilibrium temperature of 2072 K was achieved. The aperture shield sustained no visible damage as a result of the exposures. This paper describes the aperture shield thermal-vacuum qualification test program including the test article, test facility, procedures, data collection, test success criteria, results and conclusions.

Kerslake, Thomas W.; Mason, Lee S.; Strumpf, Hal J.

1997-01-01

367

Design of a portable shield for space applications  

E-print Network

the shutdown reactor. Aluminum (Al) and tungsten (W) were investigated as shield materials and in addition, an analysis was performed to determine the order of these materials in a composite shield. Calculations were performed using both the semi... attenuation properties, minimum volume and mass, and possess the ability to perform at operating and accident temperatures and in radiation environments. It is known that tungsten is a suitable gamma shield and that aluminum is a suitable proton shield...

Felsher, Harry David

1991-01-01

368

Effective shielding to measure beam current from an ion source  

NASA Astrophysics Data System (ADS)

To avoid saturation, beam current transformers must be shielded from solenoid, quad, and RFQ high stray fields. Good understanding of field distribution, shielding materials, and techniques is required. Space availability imposes compact shields along the beam pipe. This paper describes compact effective concatenated magnetic shields for IFMIF-EVEDA LIPAc LEBT and MEBT and for FAIR Proton Linac injector. They protect the ACCT Current Transformers beyond 37 mT radial external fields. Measurements made at Saclay on the SILHI source are presented.

Bayle, H.; Delferrière, O.; Gobin, R.; Harrault, F.; Marroncle, J.; Senée, F.; Simon, C.; Tuske, O.

2014-02-01

369

Effective shielding to measure beam current from an ion source  

SciTech Connect

To avoid saturation, beam current transformers must be shielded from solenoid, quad, and RFQ high stray fields. Good understanding of field distribution, shielding materials, and techniques is required. Space availability imposes compact shields along the beam pipe. This paper describes compact effective concatenated magnetic shields for IFMIF-EVEDA LIPAc LEBT and MEBT and for FAIR Proton Linac injector. They protect the ACCT Current Transformers beyond 37 mT radial external fields. Measurements made at Saclay on the SILHI source are presented.

Bayle, H., E-mail: bayle@bergoz.com [Bergoz Instrumentation, Saint-Genis-Pouilly (France); Delferrière, O.; Gobin, R.; Harrault, F.; Marroncle, J.; Senée, F.; Simon, C.; Tuske, O. [CEA, Saclay (France)] [CEA, Saclay (France)

2014-02-15

370

Designing dual-plate meteoroid shields: A new analysis  

NASA Technical Reports Server (NTRS)

Physics governing ultrahigh velocity impacts onto dual-plate meteor armor is discussed. Meteoroid shield design methodologies are considered: failure mechanisms, qualitative features of effective meteoroid shield designs, evaluating/processing meteoroid threat models, and quantitative techniques for optimizing effective meteoroid shield designs. Related investigations are included: use of Kevlar cloth/epoxy panels in meteoroid shields for the Halley's Comet intercept vehicle, mirror exposure dynamics, and evaluation of ion fields produced around the Halley Intercept Mission vehicle by meteoroid impacts.

Swift, H. F.; Bamford, R.; Chen, R.

1982-01-01

371

Shielding consideration for the SSCL experimental halls  

SciTech Connect

The Superconducting Super Collider which is being designed and built in Waxahachie, Texas consists Of series of proton accelerators, culminating in a 20 Te proton on proton collider. The collider will be in a tunnel which will be 87 km in circumference and. on average about 30 meters underground. The present design calls for two large interaction halls on the east side of the ring. The shielding for these halls is being designed for an interaction rate of 10{sup 9} Hz or 10{sup 16} interactions per year, based on 10{sup 7} seconds per operational year. SSC guidelines require that the shielding be designed to meet the criterion of 1mSv per year for open areas off site 2mSv per year for open areas on site, and 2mSv per year for controlled areas. Only radiation workers will be routinely allowed to work in controlled areas. It should be pointed that there is a potential for an accidental full beam loss in either of the experimental halls, and this event would consist of the loss of the full circulating beam up to 4 {times} 10{sup 14} protons. With the present design. the calculated dose equivalent for this event is about 10% of the annual dose equivalent for the normal p-p interactions, so that die accident condition does not control the shielding. If, for instance, local shielding within the experimental hall is introduced into the calculations, this could change. The shielding requirements presented here are controlled by the normal p-p interactions. Three important questions were addressed in the present calculations. They are (1) the thickness of the roof over the experimental halls, (2) the configuration of the shafts and adits which give access to the halls, and (3) the problem of ground water and air activation.

Bull, J.; Coyne, J.; Mokhov, N.; Stapleton, G.

1994-03-01

372

Family Life Cycle Stages  

Microsoft Academic Search

Individual life stages happen within the context of family life. This article describes Betty Carter's and Monica McGoldrick's Family Life Cycle stages as a context for Eric Erikson's stages of psychosocial development, Daniel Levinson's Stages of a Man's Life, and Jean Piaget's stages of cognitive development. The author juxtaposes the tasks of each family life stage with the individual life

M. A. Armour

1995-01-01

373

Refractory metal shielding /insulation/ increases operating range of induction furnace  

NASA Technical Reports Server (NTRS)

Thermal radiation shield contains escaping heat from an induction furnace. The shield consists of a sheet of refractory metal foil and a loosely packed mat of refractory metal fibers in a concentric pattern. This shielding technique can be used for high temperature ovens, high temperature fluid lines, and chemical reaction vessels.

Ebihara, B. T.

1965-01-01

374

Distribution, structure, and formation of Holocene lava shields in Iceland  

Microsoft Academic Search

Lava shields in Iceland are monogenic shield volcanoes mostly composed of primitive basalts, picrite and olivine tholeiite. The Holocene shields are restricted in space and time: in space they are essentially confined to the North and West Volcanic Zones; in time they are essentially confined to the early part of the Holocene. The volcanic zones are characterised by volcanic systems,

Ruth E. B. Andrew; Agust Gudmundsson

2007-01-01

375

Dose buildup factor formula for double-layered shields  

Microsoft Academic Search

In radiation shielding, health physics, and radioactive waste management, it is very important to know buildup factors for various materials and their combinations used as multilayer shields. In this work, a general formula that computes buildup factors for double-layer shields was developed on the basis of Monte Carlo photon transport using the MCNP code. Formulas for buildup factors for double-layer

M. Guvendik; N. Tsoulfanidis

1999-01-01

376

Superconducting r. f. radiation shield for high q circuits  

Microsoft Academic Search

The patent relates to a superconducting rf (radiofrequency) radiation shield and method of constructing said shield. The shield structure is fabricated by wrapping a superconducting ribbon around a cylindrical form with an approximately 50 percent overlap. A thin Teflon tape is employed to insulate successive turns of the ribbon. End plugs may be provided by placing a flat sheet of

Koren

1971-01-01

377

DARHT : integration of shielding design and analysis with facility design  

Microsoft Academic Search

The design of the interior portions of the Dual Axis Radiographic Hydrodynamic Test (DARHT) Facility incorporated shielding and controls from the beginning of the installation of the Accelerators. The purpose of the design and analysis was to demonstrate the adequacy of shielding or to determine the need for additional shielding or controls. Two classes of events were considered: (1) routine

R. L. Boudrie; T. H. Brown; W. E. Gilmore; Downing J. N. Jr; Alan Hack; D. A. McClure; C. A. Nelson; E. Alan Wadlinger; M. V. Zumbro

2002-01-01

378

Lightning attachment models and perfect shielding angle of transmission lines  

Microsoft Academic Search

General relationships for the estimation of the perfect shielding angle of overhead transmission lines have been derived by performing shielding analysis on the basis of several lightning attachment models, including a recently introduced statistical one. The interdependence of perfect shielding angle, transmission line height and minimum current causing flashover of insulation is demonstrated as influenced by the lightning attachment model

Pantelis N. Mikropoulos; Thomas E. Tsovilis

2009-01-01

379

Three dimensional hypervelocity impact simulation for orbital debris shield design  

Microsoft Academic Search

This paper assesses a Whipple shield impact simulation method which is both accurate and computationally efficient. The paper documents the simulation methodology and results of Whipple shield simulations at an oblique impact angle of 30°. These results are compared with HVI experiments to demonstrate the accuracy of the simulation technique. In addition, simulations of Whipple shields in the velocity regime

Justin H. Kerr; Eric P. Fahrenthold

1997-01-01

380

How stable are the 'stable ancient shields'?  

NASA Astrophysics Data System (ADS)

"Archean cratons are relatively flat, stable regions of the crust that have remained undeformed since the Precambrian, forming the ancient cores of the continents" (King, EPSL, 2005). While this type of statement is supported by a wealth of constraints in the case of episodes of thoroughgoing ductile deformation affecting shield regions of Archean and also Peleoproterozoic age, a growing amount of research indicates that shields are not nearly as structurally stable within the broad field of environmental conditions leading to brittle deformation. In fact, old crystalline basements usually present compelling evidence of long brittle deformation histories, often very complex and challenging to unfold. Recent structural and geochronological studies point to a significant mechanical instability of the shield areas, wherein large volumes of 'stable' rocks actually can become saturated with fractures and brittle faults soon after regional cooling exhumes them to below c. 300-350° C. How cold, rigid and therefore strong shields respond to applied stresses remains, however, still poorly investigated and understood. This in turn precludes a better definition of the shallow rheological properties of large, old crystalline blocks. In particular, we do not yet have good constraints on the mechanisms of mechanical reactivation that control the partial (if not total) accommodation of new deformational episodes by preexisting structures, which remains a key to untangle brittle histories lasting several hundred Myr. In our analysis, we use the Svecofennian Shield (SS) as an example of a supposedly 'stable' region with Archean nucleii and Paleoproterozoic cratonic areas to show how it is possible to unravel the details of brittle histories spanning more than 1.5 Gyr. New structural and geochronological results from Finland are integrated with a review of existing data from Sweden to explore how the effects of far-field stresses are partitioned within a shield, which was growing progressively saturated with fractures as time passed from its initial consolidation. The comparison of time-constrained paleostress data derived from three different locations of the shield shows a remarkably similar stress evolution through time, despite the different geological frameworks of the investigated areas. This suggests that the southern SS has behaved as a coherent rigid crustal block since the Late Mesoproterozoic. By that time, the SS had already reached structural maturity with respect to the saturation of brittle structural features. Therefore, structural reactivation rather than generation of new faults and fractures is the key mechanism that has controlled the mechanical evolution of the shield and that will steer its future evolution within the brittle regime. Comparable brittle structural histories within parts of the shield that are far apart also imply that far-field stresses can propagate over large distances and can lead to similar deformational histories, with the local geological conditions only playing a second-order role on the final brittle strain pattern recorded by the rock.

Viola, Giulio; Mattila, Jussi

2014-05-01

381

Passive Superconducting Shielding: Experimental Results and Computer Models  

NASA Technical Reports Server (NTRS)

Passive superconducting shielding for magnetic refrigerators has advantages over active shielding and passive ferromagnetic shielding in that it is lightweight and easy to construct. However, it is not as easy to model and does not fail gracefully. Failure of a passive superconducting shield may lead to persistent flwc and persistent currents. Unfortunately, modeling software for superconducting materials is not as easily available as is software for simple coils or for ferromagnetic materials. This paper will discuss ways of using available software to model passive superconducting shielding.

Warner, Brent; Kamiya, Koki

2003-01-01

382

Passive Superconducting Shielding: Experimental Results and Computer Models  

NASA Technical Reports Server (NTRS)

Passive superconducting shielding for magnetic refrigerators has advantages over active shielding and passive ferromagnetic shielding in that it is lightweight and easy to construct. However, it is not as easy to model and does not fail gracefully. Failure of a passive superconducting shield may lead to persistent flux and persistent currents. Unfortunately, modeling software for superconducting materials is not as easily available as is software for simple coils or for ferromagnetic materials. This paper will discuss ways of using available software to model passive superconducting shielding.

Warner, B. A.; Kamiya, K.

2003-01-01

383

Potential Polymeric Sphere Construction Materials for a Spacecraft Electrostatic Shield  

NASA Technical Reports Server (NTRS)

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.

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

2006-01-01

384

Building America  

SciTech Connect

IBACOS researched the constructability and viability issues of using high performance windows as one component of a larger approach to building houses that achieve the Building America 70% energy savings target.

Brad Oberg

2010-12-31

385

Shields for Enhanced Protection Against High-Speed Debris  

NASA Technical Reports Server (NTRS)

A report describes improvements over the conventional Whipple shield (two thin, spaced aluminum walls) for protecting spacecraft against high-speed impacts of orbiting debris. The debris in question arise mainly from breakup of older spacecraft. The improved shields include exterior bumper layers composed of hybrid fabrics woven from combinations of ceramic fibers and high-density metallic wires or, alternatively, completely metallic outer layers composed of high-strength steel or copper wires. These shields are designed to be light in weight, yet capable of protecting against orbital debris with mass densities up to about 9 g/cm3, without generating damaging secondary debris particles. As yet another design option, improved shields can include sparsely distributed wires made of shape-memory metals that can be thermally activated from compact storage containers to form shields of predetermined shape upon arrival in orbit. The improved shields could also be used to augment shields installed previously.

Christiansen, Eric L.; Kerr, Justin H.

2003-01-01

386

Magnetic shielding for the Fermilab Vertical Cavity Test Facility  

SciTech Connect

A superconducting RF cavity has to be shielded from magnetic fields present during cool down below the critical temperature to avoid freezing in the magnetic flux at localized impurities, thereby degrading the cavity intrinsic quality factor Q{sub 0}. The magnetic shielding designed for the Fermilab vertical cavity test facility (VCTF), a facility for CW RF vertical testing of bare ILC 1.3 GHz 9-cell SRF cavities, was recently completed. For the magnetic shielding design, we used two cylindrical layers: a room temperature 'outer' shield of Amumetal (80% Ni alloy), and a 2K 'inner' shield of Cryoperm 10. The magnetic and mechanical design of the magnetic shielding and measurement of the remanent magnetic field inside the shielding are described.

Ginsburg, Camille M.; Reid, Clark; Sergatskov, Dmitri A.; /Fermilab

2008-09-01

387

Shields for Enhanced Protection Against High-Speed Debris  

NASA Technical Reports Server (NTRS)

A report describes improvements over the conventional Whipple shield (two thin, spaced aluminum walls) for protecting spacecraft against high-speed impacts of orbiting debris. The debris in question arises mainly from breakup of older spacecraft. The improved shields include exterior "bumper" layers composed of hybrid fabrics woven from combinations of ceramic fibers and high-density metallic wires or, alternatively, completely metallic outer layers composed of high-strength steel or copper wires. These shields are designed to be light in weight, yet capable of protecting against orbital debris with mass densities up to about 9 g/cubic cm, without generating damaging secondary debris particles. As yet another design option, improved shields can include sparsely distributed wires made of shape memory metals that can be thermally activated from compact storage containers to form shields of predetermined shape upon arrival in orbit. The improved shields could also be used to augment shields installed previously.

Christiansen, Eric L.; Kerr, Justin H.

2003-01-01

388

Electronically shielded solid state charged particle detector  

DOEpatents

An electronically shielded solid state charged particle detector system having enhanced radio frequency interference immunity includes a detector housing with a detector entrance opening for receiving the charged particles. A charged particle detector having an active surface is disposed within the housing. The active surface faces toward the detector entrance opening for providing electrical signals representative of the received charged particles when the received charged particles are applied to the active surface. A conductive layer is disposed upon the active surface. In a preferred embodiment, a nonconductive layer is disposed between the conductive layer and the active surface. The conductive layer is electrically coupled to the detector housing to provide a substantially continuous conductive electrical shield surrounding the active surface. The inner surface of the detector housing is supplemented with a radio frequency absorbing material such as ferrite. 1 fig.

Balmer, D.K.; Haverty, T.W.; Nordin, C.W.; Tyree, W.H.

1996-08-20

389

Supplemental heating of deposition tooling shields  

DOEpatents

A method of reducing particle generation from the thin coating deposited on the internal surfaces of a deposition chamber which undergoes temperature variation greater than 100.degree. C. comprising maintaining the temperature variation of the internal surfaces low enough during the process cycle to keep thermal expansion stresses between the coating and the surfaces under 500 MPa. For titanium nitride deposited on stainless steel, this means keeping temperature variations under approximately 70.degree. C. in a chamber that may be heated to over 350.degree. C. during a typical processing operation. Preferably, a supplemental heater is mounted behind the upper shield and controlled by a temperature sensitive element which provides feedback control based on the temperature of the upper shield.

Ohlhausen, James A. (Albuquerque, NM); Peebles, Diane E. (Albuquerque, NM); Hunter, John A. (Albuquerque, NM); Eckelmeyer, Kenneth H. (Albuquerque, NM)

2000-01-01

390

Spallation of the Galileo probe heat shield  

NASA Technical Reports Server (NTRS)

The Galileo probe heat shield will encounter severe radiative and convective heating during entry into Jupiter's atmosphere. The shield is made of two different carbon phenolic composites; one is chopped-molded, and the other is tape-wrapped, both of which tend to spall under intense heating conditions. To characterize this phenomenon, an experimental program, using a gasdynamic laser, was initiated. Tests were performed at a variety of radiation intensities, and both the total and spallation mass-loss rates were measured and correlated with intensity. These correlations were then applied to calculated flight heating conditions for two model atmospheres. Entry of a 310-kg probe into the nominal atmosphere would result in a spallation mass loss of 6.3 kg, or 7.4% of the expected thermochemical mass loss. Similarly, entry of that probe into the cool-dense atmosphere would result in 11.9 kg of spallation, or about 10% of the expected thermochemical mass loss.

Lundell, J. H.

1982-01-01

391

Debye shielding in a nonextensive plasma  

SciTech Connect

The phenomenon of Debye Shielding is revisited within the theoretical framework of the Tsallis statistical mechanics. The plasma consists of nonextensive electrons and ions. Both the effective Debye length {lambda}{sub D}{sup q} and the fall-off of the electrostatic potential {Phi} are considered and a parameter study conducted. Owing to electron nonextensivity, the critical Mach number derived from the modified Bohm sheath criterion may become less than unity allowing therefore ions with speed less than ion-acoustic speed to enter the sheath from the main body of the plasma. Considering the wide relevance of collective processes, our analysis may be viewed as a first step toward a more comprehensive Debye shielding and electrostatic plasma sheath in nonequilibrium plasmas.

Ait Gougam, Leila; Tribeche, Mouloud [Faculty of Sciences-Physics, Theoretical Physics Laboratory (TPL), University of Bab-Ezzouar, U.S.T.H.B, B.P. 32, El Alia, Algiers 16111 (Algeria)

2011-06-15

392

Electronically shielded solid state charged particle detector  

DOEpatents

An electronically shielded solid state charged particle detector system having enhanced radio frequency interference immunity includes a detector housing with a detector entrance opening for receiving the charged particles. A charged particle detector having an active surface is disposed within the housing. The active surface faces toward the detector entrance opening for providing electrical signals representative of the received charged particles when the received charged particles are applied to the active surface. A conductive layer is disposed upon the active surface. In a preferred embodiment, a nonconductive layer is disposed between the conductive layer and the active surface. The conductive layer is electrically coupled to the detector housing to provide a substantially continuous conductive electrical shield surrounding the active surface. The inner surface of the detector housing is supplemented with a radio frequency absorbing material such as ferrite.

Balmer, David K. (155 Coral Way, Broomfield, CO 80020); Haverty, Thomas W. (1173 Logan, Northglenn, CO 80233); Nordin, Carl W. (7203 W. 32nd Ave., Wheatridge, CO 80033); Tyree, William H. (1977 Senda Rocosa, Boulder, CO 80303)

1996-08-20

393

Healthy Buildings?  

ERIC Educational Resources Information Center

Health problems related to school buildings can be categorized in five major areas: sick-building syndrome; health-threatening building materials; environmental hazards such as radon gas and asbestos; lead poisoning; and poor indoor air quality due to smoke, chemicals, and other pollutants. This paper provides an overview of these areas,…

Grubb, Deborah

394

Funding Opportunity: Partnerships for Innovation (PFI): Building Innovation Capacity Sponsor: National Science Foundation  

E-print Network

involves an early stage that focuses on building innovation capacity and the other, which involves a later stage that focuses on accelerating innovation research. This program solicitation, PartnershipsFunding Opportunity: Partnerships for Innovation (PFI): Building Innovation Capacity (PFI: BIC

Suzuki, Masatsugu

395

Shielding analyses: the rabbit vs the turtle?  

SciTech Connect

This paper compares solutions using Monte Carlo and discrete- ordinates methods applied to two actual shielding situations in order to make some general observations concerning the efficiency and advantages/disadvantages of the two approaches. The discrete- ordinates solutions are performed using two-dimensional geometries, while the Monte Carlo approaches utilize three-dimensional geometries with both multigroup and point cross-section data.

Broadhead, B.L.

1996-12-31

396

Dry fuel storage cask shielding benchmarks  

SciTech Connect

A great deal of operational data is now available from NUHOMS dry storage installations. Shielding benchmark calculations have been performed for two metal transfer casks, each fuel designs, and three concrete storage casks to determine why the design calculations exhibit a wide margin of conservatism. Modification of the fuel assembly source term calculations were found necessary to more accurately predict gamma and neutron dose rates.

Jones, K.B.; Thomas, B.D. [VECTRA Technologies, Inc., San Jose, CA (United States)

1995-12-01

397

Hypervelocity impact simulations of Whipple shields  

NASA Technical Reports Server (NTRS)

The problem associated with protecting space vehicles from space debris impact is described. Numerical simulation is espoused as a useful complement to experimentation: as a means to help understand and describe the hypervelocity impact phenomena. The capabilities of a PC-based hydrocode, ZeuS, are described, for application to the problem of hypervelocity impact. Finally, results of ZeuS simulations, as applied to the problem of bumper shield impact, are presented and compared with experimental results.

Segletes, Steven B.; Zukas, Jonas A.

1992-01-01

398

Enrichment Determination of Uranium in Shielded Configurations  

SciTech Connect

The determination of the enrichment of uranium is required in many safeguards and security applications. Typical methods of determining the enrichment rely on detecting the 186 keV gamma ray emitted by {sup 235}U. In some applications, the uranium is surrounded by external shields, and removal of the shields is undesirable. In these situations, methods relying on the detection of the 186 keV gamma fail because the gamma ray is shielded easily. Oak Ridge National Laboratory (ORNL) has previously measured the enrichment of shielded uranium metal using active neutron interrogation. The method consists of measuring the time distribution of fast neutrons from induced fissions with large plastic scintillator detectors. To determine the enrichment, the measurements are compared to a calibration surface that is created from Monte Carlo simulations where the enrichment in the models is varied. In previous measurements, the geometry was always known. ORNL is extending this method to situations where the geometry and materials present are not known in advance. In the new method, the interrogating neutrons are both time and directionally tagged, and an array of small plastic scintillators measures the uncollided interrogating neutrons. Therefore, the attenuation through the item along many different paths is known. By applying image reconstruction techniques, an image of the item is created which shows the position-dependent attenuation. The image permits estimating the geometry and materials present, and these estimates are used as input for the Monte Carlo simulations. As before, simulations predict the time distribution of induced fission neutrons for different enrichments. Matching the measured time distribution to the closest prediction from the simulations provides an estimate of the enrichment. This presentation discusses the method and provides results from recent simulations that show the importance of knowing the geometry and materials from the imaging system.

Crye, Jason Michael [ORNL] [ORNL; Hall, Howard L [ORNL] [ORNL; McConchie, Seth M [ORNL] [ORNL; Mihalczo, John T [ORNL] [ORNL; Pena, Kirsten E [ORNL] [ORNL

2011-01-01

399

Shielded serpentine traveling wave tube deflection structure  

SciTech Connect

A shielded serpentine slow wave deflection structure is disclosed having a serpentine signal conductor within a channel groove. The channel groove is formed by a serpentine channel in a trough plate and a ground plane. The serpentine signal conductor is supported at its ends by coaxial feed through connectors. A beam interaction trough intersects the channel groove to form a plurality of beam interaction regions wherein an electron beam may be deflected relative to the serpentine signal conductor. 4 figures.

Hudson, C.L.; Spector, J.

1994-12-27

400

SQUID holder with high magnetic shielding  

NASA Technical Reports Server (NTRS)

A SQUID holder designed for high magnetic shielding is discussed. It is shown how to estimate the attenuation of the magnetic field from the normal magnetic modes for an approximate geometry. The estimate agrees satisfactorily with the attenuation measured with a commercial RF SQUID installed in the holder. The holder attenuates external magnetic fields by more than 10 to the 9th at the SQUID input. With the SQUID input shorted, the response to external fields is 0.00001 Phi(0)/G.

Rigby, K. W.; Marek, D.; Chui, T. C. P.

1990-01-01

401

Activation characteristics of concrete shields containing colemanite  

NASA Astrophysics Data System (ADS)

This paper presents the theoretical results of the activation characteristics of a concrete shield containing colemanite, which is a boron-bearing mineral. Calculations are performed with a computer code, ANITA. The total activity and dose values of the sheilds with or without colemanite are compared for different continuous irradiation periods and neutron fluxes. The effect of colemanite on the activity is discussed by investigating the predominant radioisotopes at the shutdown radioactive inventory and the reactions that produce them.

Yarar, Yasemin

1996-10-01

402

Shielding analysis and design of the KIPT experimental neutron source facility of Ukraine.  

SciTech Connect

Argonne National Laboratory (ANL) of USA and Kharkov Institute of Physics and Technology (KIPT) of Ukraine have been collaborating on the conceptual design development of an experimental neutron source facility based on the use of an electron accelerator driven subcritical (ADS) facility [1]. The facility uses the existing electron accelerators of KIPT in Ukraine. The neutron source of the sub-critical assembly is generated from the interaction of 100 KW electron beam with a natural uranium target. The electron beam has a uniform spatial distribution and the electron energy in the range of 100 to 200 MeV, [2]. The main functions of the facility are the production of medical isotopes and the support of the Ukraine nuclear power industry. Reactor physics experiments and material performance characterization will also be carried out. The subcritical assembly is driven by neutrons generated by the electron beam interactions with the target material. A fraction of these neutrons has an energy above 50 MeV generated through the photo nuclear interactions. This neutron fraction is very small and it has an insignificant contribution to the subcritical assembly performance. However, these high energy neutrons are difficult to shield and they can be slowed down only through the inelastic scattering with heavy isotopes. Therefore the shielding design of this facility is more challenging relative to fission reactors. To attenuate these high energy neutrons, heavy metals (tungsten, iron, etc.) should be used. To reduce the construction cost, heavy concrete with 4.8 g/cm{sup 3} density is selected as a shielding material. The iron weight fraction in this concrete is about 0.6. The shape and thickness of the heavy concrete shield are defined to reduce the biological dose equivalent outside the shield to an acceptable level during operation. At the same time, special attention was give to reduce the total shield mass to reduce the construction cost. The shield design is configured to maintain the biological dose equivalent during operation {le} 0.5 mrem/h inside the subcritical hall, which is five times less than the allowable dose for working forty hours per week for 50 weeks per year. This study analyzed and designed the thickness and the shape of the radial and top shields of the neutron source based on the biological dose equivalent requirements inside the subcritical hall during operation. The Monte Carlo code MCNPX is selected because of its capabilities for transporting electrons, photons, and neutrons. Mesh based weight windows variance reduction technique is utilized to estimate the biological dose outside the shield with good statistics. A significant effort dedicated to the accurate prediction of the biological dose equivalent outside the shield boundary as a function of the shield thickness without geometrical approximations or material homogenization. The building wall was designed with ordinary concrete to reduce the biological dose equivalent to the public with a safety factor in the range of 5 to 20.

Zhong, Z.; Gohar, M. Y. A.; Naberezhnev, D.; Duo, J.; Nuclear Engineering Division

2008-10-31

403

GRAVITATIONAL FIELD SHIELDING AND SUPERNOVA EXPLOSIONS  

SciTech Connect

A new mechanism for supernova explosions called gravitational field shielding is proposed, in accord with a five-dimensional fully covariant Kaluza-Klein theory with a scalar field that unifies the four-dimensional Einsteinian general relativity and Maxwellian electromagnetic theory. It is shown that a dense compact collapsing core of a star will suddenly turn off or completely shield its gravitational field when the core collapses to a critical density, which is inversely proportional to the square of mass of the core. As the core suddenly turns off its gravity, the extremely large pressure immediately stops the core collapse and pushes the mantle material of supernova moving outward. The work done by the pressure in the expansion can be the order of energy released in a supernova explosion. The gravity will resume and stop the core from a further expansion when the core density becomes less than the critical density. Therefore, the gravitational field shielding leads a supernova to impulsively explode and form a compact object such as a neutron star as a remnant. It works such that a compressed spring will shoot the oscillator out when the compressed force is suddenly removed.

Zhang, T. X. [Physics Department, Alabama A and M University, Normal, AL 35762 (United States)

2010-12-20

404

Transparent self-cleaning dust shield  

DOEpatents

A transparent electromagnetic shield to protect solar panels and the like from dust deposition. The shield is a panel of clear non-conducting (dielectric) material with embedded parallel electrodes. The panel is coated with a semiconducting film. Desirably the electrodes are transparent. The electrodes are connected to a single-phase AC signal or to a multi-phase AC signal that produces a travelling electromagnetic wave. The electromagnetic field produced by the electrodes lifts dust particles away from the shield and repels charged particles. Deposited dust particles are removed when the electrodes are activated, regardless of the resistivity of the dust. Electrostatic charges on the panel are discharged by the semiconducting film. When used in conjunction with photovoltaic cells, the power for the device may be obtained from the cells themselves. For other surfaces, such as windshields, optical windows and the like, the power must be derived from an external source. One embodiment of the invention employs monitoring and detection devices to determine when the level of obscuration of the screen by dust has reached a threshold level requiring activation of the dust removal feature.

Mazumder, Malay K.; Sims, Robert A.; Wilson, James D.

2005-06-28

405

Atlas Breached Waste Package and Drip Shield Experiments: Breached Drip Shield Tests  

SciTech Connect

The Engineered Barrier System (EBS) represents one system in the performance of the Yucca Mountain high-level radioactive waste (HLW) repository to isolate and prevent the transport of radionuclides from the site to the accessible environment. Breached Waste Package and Drip Shield Experiments (BWPDSE) were performed at the Department of Energy's National Nuclear Security Administration Nevada Support Facility in North Las Vegas, NV in the A-1 lowbay between May 2, 2002 and July 25, 2002. Data collected from the BWPDSE will be used to support the flux splitting model used in Analysis and Modeling Report ANL-WIS-PA-000001 REV 00 ICN 03 ''EBS Radionuclide Transport Abstraction'' (BSC 2001a). Tests were conducted by dripping water from heights representing the drift crown or wall on a full-scale section of a drip shield with both smooth and rough surfaces. The drip shields had machined square breaches that represent the general corrosion breaches or nodes in the ''WAPDEG Analysis of Waste Package and Drip Shield Degradation'' AMR (CRWMS M&O 2000d). Tests conducted during the BWPDSE included: initial tests to determine the splash radius distances and spread factor from the line of drip impact, single patch tests to determine the amount of water collected in target breaches from splashing or rivulet flow, multiple patch tests to determine the amount of water collected in several breaches from both splashing and rivulet flow, and bounding flow rate tests. Supplemental data were collected to provide additional information for rivulet spread, pan evaporation in the test chamber, and water temperatures of the input water and drip shield surface water. The primary flow mechanism observed on both smooth and rough surfaces was rivulet flow, not film flow. Lateral rivulet spread distances were, in general, wider on the smooth drip shield surface than on the rough drip shield surface. There were substantial differences between the mechanisms of rivulet formation and movement on smooth and rough drip shield surfaces. Water collected in breaches was a function of the location of drip impact upstream from the target breach, i.e., impact breaches must be directly above or slightly to the side of the breaches in order for a substantial volume of water to collect in breaches. Splash droplets contributed a small portion of the water collected in breaches. Mass balances showed that evaporation from the drip shield was a large component of water loss. This was particularly manifested during low flow runs of the bounding flow rate tests where test duration was around five hours.

Z. P. Walton

2003-05-28

406

Preventing Accidental Ignition of Upper-Stage Rocket Motors  

NASA Technical Reports Server (NTRS)

A report presents a proposal to reduce the risk of accidental ignition of certain upper-stage rocket motors or other high energy hazardous systems. At present, mechanically in-line initiators are used for initiation of many rocket motors and/or other high-energy hazardous systems. Electrical shorts and/or mechanical barriers, which are the basic safety devices in such systems, are typically removed as part of final arming or pad preparations while personnel are present. At this time, static discharge, test equipment malfunction, or incorrect arming techniques can cause premature firing. The proposal calls for a modular out-of-line ignition system incorporating detonating-cord elements, identified as the donor and the acceptor, separated by an air gap. In the safe configuration, the gap would be sealed with two shields, which would prevent an accidental firing of the donor from igniting the system. The shields would be removed to enable normal firing, in which shrapnel generated by the donor would reliably ignite the acceptor to continue the ordnance train. The acceptor would then ignite a through bulkhead initiator (or other similar device), which would ignite the motor or high-energy system. One shield would be remotely operated and would be moved to the armed position when a launch was imminent or conversely returned to the safe position if the launch were postponed. In the event of failure of the remotely operated shield, the other shield could be inserted manually to safe the system.

Hickman, John; Morgan, Herbert; Cooper, Michael; Murbach, Marcus

2005-01-01

407

A MODEL BUILDING CODE ARTICLE ON FALLOUT SHELTERS WITH RECOMMENDATIONS FOR INCLUSION OF REQUIREMENTS FOR FALLOUT SHELTER CONSTRUCTION IN FOUR NATIONAL MODEL BUILDING CODES.  

ERIC Educational Resources Information Center

A MODEL BUILDING CODE FOR FALLOUT SHELTERS WAS DRAWN UP FOR INCLUSION IN FOUR NATIONAL MODEL BUILDING CODES. DISCUSSION IS GIVEN OF FALLOUT SHELTERS WITH RESPECT TO--(1) NUCLEAR RADIATION, (2) NATIONAL POLICIES, AND (3) COMMUNITY PLANNING. FALLOUT SHELTER REQUIREMENTS FOR SHIELDING, SPACE, VENTILATION, CONSTRUCTION, AND SERVICES SUCH AS ELECTRICAL…

American Inst. of Architects, Washington, DC.

408

Stages of Neuroblastoma  

MedlinePLUS

... of neuroblastoma is based on risk groups. After neuroblastoma has been diagnosed, tests are done to find ... liver cancer. The following stages are used for neuroblastoma: Stage 1 In stage 1 , the tumor is ...

409

Staging of Lung Cancer  

MedlinePLUS

... it important to know the stage of my lung cancer? Finding out the stage of your lung cancer ... you. How does staging differ between small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC)? ...

410

Pancreatic Cancer Stage 4  

MedlinePLUS

... My Pictures Browse Search Quick Search Image Details Pancreatic Cancer Stage 4 View/Download: Small: 533x576 View Download Add to My Pictures Title: Pancreatic Cancer Stage 4 Description: Stage IV pancreatic cancer; drawing ...

411

Pancreatic Cancer Stage 3  

MedlinePLUS

... My Pictures Browse Search Quick Search Image Details Pancreatic Cancer Stage 3 View/Download: Small: 720x576 View Download Add to My Pictures Title: Pancreatic Cancer Stage 3 Description: Stage III pancreatic cancer; drawing ...

412

FUSION OF LIDAR DATA AND OPTICAL IMAGERY FOR BUILDING MODELING  

Microsoft Academic Search

This paper presents a scheme for building detection and building reconstruction from LIDAR data and optical imagery. The proposed scheme comprises two major parts: (1) detection of building regions, and (2) reconstruction of building models. Spatial registration of LIDAR data and optical images is performed as data preprocessing. Then, at the first stage, a region-based segmentation and knowledge-based classification are

Liang-Chien Chen; Tee-Ann Teo; Yi-Chen Shao; Yen-Chung Lai; Jiann-Yeou Rau

413

Residential building energy analysis : development and uncertainty assessment of a simplified model  

E-print Network

Effective design of energy-efficient buildings requires attention to energy issues during the preliminary stages of design. To aid in the early consideration of a building's future energy usage, a simplified building energy ...

Spindler, Henry C. (Henry Carlton), 1970-

1998-01-01

414

1. Northeast face of missile site control building, commonly known ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. Northeast face of missile site control building, commonly known as the missile site radar building, showing open blast door #BD2. This emergency escape, at stair no. 12, is NEMP/RFI-shielded and 16" thick. The large circle in the center is the radar face, also known as the antennae array aperture. The small circle to the right of the radar face is the "Q" channel. The antennae atop the turret provided lightning protection for the building - Stanley R. Mickelsen Safeguard Complex, Missile Site Control Building, Northeast of Tactical Road; southeast of Tactical Road South, Nekoma, Cavalier County, ND

415

Moderately shielded high-Tc SQUID system for rat MCG  

NASA Astrophysics Data System (ADS)

Recently, we have developed a 5-channel high-Tc SQUID system with one signal channel intended for rat magnetocardiography (MCG) in moderately shielded or "quiet" real environment. This system is an adapted version of a human MCG system which has been improved with respect to user-friendliness and stability. A dewar with a cold-warm distance of 7 mm and a refill cycle time of up to one week is utilized. The implemented high-Tc SQUIDs are single-layer devices with grain boundary junctions fabricated at KRISS with laser ablation on 10 mm × 10 mm STO substrates. In order to cancel environmental magnetic noise, three of the five SQUIDs are arranged to build an axial software first-order or second-order gradiometer with a base line of 35 mm. The other two SQUIDs are used for balancing. To overcome previous system instabilities, we have implemented an Earth field compensation for each SQUID. For this, the SQUIDs were mounted in capsules containing integrated field compensation coils. The three Earth field components are measured with an additional triaxial fluxgate, and compensated at the SQUID locations using the low-noise current source of the SQUID readout electronics. This way, the SQUIDs can be cooled and operated in a low residual field that improves system stability and reduces low-frequency SQUID noise. It is even possible to slowly move the dewar in the Earth field (dynamic field compensation). Different noise cancellation procedures were optimized and compared employing a periodic signal source.

Bechstein, S.; Kim, I.-S.; Drung, D.; Novikov, I.; Schurig, Th

2010-06-01

416

Radiation shielding for future space exploration missions  

NASA Astrophysics Data System (ADS)

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 weighted figure of merit (WFoM) approach that quantifies the effectiveness of a candidate material to shield space crews from the whole of the space radiation environment. The results of the WFoM approach should prove useful to designers and engineers in seeking alternative materials suitable for the construction of spacecraft or planetary surface habitats needed for long-term space exploration missions. The dosimetric measurements in this study have confirmed the principle of good space radiation shielding design by showing that low-Z¯ materials are most effective at reducing absorbed dose and dose equivalent while high-Z¯ materials are to be avoided. The relatively high WFoMs of carbon composite and lunar- and Martian-regolith composite could have important implications for the design and construction of future spacecraft or planetary surface habitats. The ground-based measurements conducted in this study have validated the heavy ion extension of FLUKA by producing normalized differential LET fluence spectra that are in good agreement with experiment.

DeWitt, Joel Michael

417

Safety evaluation for packaging (onsite) for concrete-shielded RHTRU waste drum for the 327 postirradiation testing laboratory  

SciTech Connect

This safety evaluation for packaging authorizes onsite transport of Type B quantities of radioactive material in the Concrete- Shielded Remote-Handled Transuranic Waste (RH TRU) Drum per WHC-CM-2-14, Hazardous Material Packaging and Shipping. The drum will be used for transport of 327 Building legacy waste from the 300 Area to the Transuranic Waste Storage and Assay Facility in the 200 West Area and on to a Solid Waste Storage Facility, also in the 200 Area.

Adkins, H.E.

1996-10-29

418

Safety evaluation for packaging (onsite) for the concrete-shielded RH TRU drum for the 327 Postirradiation Testing Laboratory  

SciTech Connect

This safety evaluation for packaging authorizes onsite transport of Type B quantities of radioactive material in the Concrete Shielded Remote-Handled Transuranic Waste (RH TRU) Drum per HNF-PRO-154, Responsibilities and Procedures for all Hazardous Material Shipments. The drum will be used for transport of 327 Building legacy waste from the 300 Area to a solid waste storage facility on the Hanford Site.

Smith, R.J.

1998-03-31

419

Methods of shield analysis for protection against electrons in space  

NASA Technical Reports Server (NTRS)

It is anticipated that many future manned space operations will be radiation limited and that laminated wall structures and the use of new materials will be required to reduce radiation exposure. Methods for electron shield analysis are reviewed in light of anticipated needs in the space program. The most general method is still the Monte Carlo method, which is of limited usefulness for shield analysis due to excessive computer requirements. Methods based on energy deposition coefficients or energy transmission and reflection factors are quite accurate, but are currently limited to aluminum shield material. Analytical methods based on Mar's approximation for the electron transmission factor are relatively general and computer efficient but seriously underestimate shield requirements. A correction to methods using Mar's approximate transmission factor is derived herein and results in a slightly conservative estimate of shield requirements. Techniques for laminated shield design are still lacking.

Wilson, J. W.; Denn, F. M.

1977-01-01

420

Structural monitoring of metro infrastructure during shield tunneling construction.  

PubMed

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. PMID:25032238

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

2014-01-01

421

Radiation shielding for underground low-background experiments  

E-print Network

The design task of creating an efficient radiation shield for the new COBRA double-beta decay experiment led to a comprehensive study of commercially available shielding materials. The aim was to find the most efficient combination of materials under the constraints of an extreme low-background experiment operating in a typical underground laboratory. All existing shield configurations for this type of experiment have been found to perform sub-optimally in comparison to the class of multilayered configurations proposed in this study. The method used here to create a specific shield configuration should yield a close to optimal result when applied to any experiment utilising a radiation shield. In particular, the survey of single material response to a given radiation source turns out to give a guideline for the construction of efficient multilayer shields.

D. Y Stewart; P. F. Harrison; B. Morgan; Y. A. Ramachers

2006-07-31

422

Green Buildings  

NSDL National Science Digital Library

From the Department of Energy's Center of Excellence for Sustainable Development, this Green Buildings site serves as a detailed metapage for environmentally conscious architects, engineers, and builders. As the introduction to the site points out, "The design, construction, and maintenance of buildings has a tremendous impact on our environment and our natural resources." The site offers carefully summarized links to relevant Websites and publications on topics such as building principles, building programs, rating systems, affordable housing, codes/ordinances, educational materials, and more. This site may be of interest to those who want practical applications for protecting the environment.

423

Building Together  

NSDL National Science Digital Library

In this Bob the Builder(TM)-themed activity, learners explore what it means to work together as a team. Learners repeat the phrase “Can We Build It?(TM) Yes We Can!” until they can chant it together as a team. Then, learners repeat the chant at each activity station. Learners rotate through the stations where they build with blocks, LEGO® bricks or other small manipulatives, hammer nails and wood, pump with water, and construct a building site by moving sand with toy trucks. This activity is featured on page 9 of the "Bob the Builder(TM) — Project: Build It" unit of study.

2014-04-30

424

Rotating-shield brachytherapy for cervical cancer  

NASA Astrophysics Data System (ADS)

In this treatment planning study, the potential benefits of a rotating shield brachytherapy (RSBT) technique based on a partially-shielded electronic brachytherapy source were assessed for treating cervical cancer. Conventional intracavitary brachytherapy (ICBT), intracavitary plus supplementary interstitial (IS+ICBT), and RSBT treatment plans for azimuthal emission angles of 180° (RSBT-180) and 45° (RSBT-45) were generated for five patients. For each patient, high-risk clinical target volume (HR-CTV) equivalent dose in 2 Gy fractions (EQD2) (?/? = 10 Gy) was escalated until bladder, rectum, or sigmoid colon tolerance EQD2 values were reached. External beam radiotherapy dose (1.8 Gy × 25) was accounted for, and brachytherapy was assumed to have been delivered in 5 fractions. IS+ICBT provided a greater HR-CTV D90 (minimum EQD2 to the hottest 90%) than ICBT. D90 was greater for RSBT-45 than IS+ICBT for all five patients, and greater for RSBT-180 than IS+ICBT for two patients. When the RSBT-45/180 plan with the lowest HR-CTV D90 that was greater than the D90 the ICBT or IS+ICBT plan was selected, the average (range) of D90 increases for RSBT over ICBT and IS+ICBT were 16.2 (6.3-27.2)and 8.5 (0.03-20.16) Gy, respectively. The average (range) treatment time increase per fraction of RSBT was 34.56 (3.68-70.41) min over ICBT and 34.59 (3.57-70.13) min over IS+ICBT. RSBT can increase D90 over ICBT and IS+ICBT without compromising organ-at-risk sparing. The D90 and treatment time improvements from RSBT depend on the patient and shield emission angle.

Yang, Wenjun; Kim, Yusung; Wu, Xiaodong; Song, Qi; Liu, Yunlong; Bhatia, Sudershan K.; Sun, Wenqing; Flynn, Ryan T.

2013-06-01

425

Shielding design at Fermilab: Calculations and measurements  

SciTech Connect

The development of the Fermilab accelerator complex during the past two decades from its concept as the ''200 BeV accelerator'' to that of the present tevatron, designed to operate at energies as high as 1 TeV, has required a coincidental refinement and development in methods of shielding design. In this paper I describe these methods as used by the radiation protection staff of Fermilab. This description will review experimental measurements which substantiate these techniques in realistic situations. Along the way, observations will be stated which likely are applicable to other protron accelerators in the multi-hundred GeV energy region, including larger ones yet to be constructed.

Cossairt, J.D.

1986-11-01

426

X-ray transmissive debris shield  

DOEpatents

An X-ray debris shield for use in X-ray lithography that is comprised of an X-ray window having a layer of low density foam exhibits increased longevity without a substantial increase in exposure time. The low density foam layer serves to absorb the debris emitted from the X-ray source and attenuate the shock to the window so as to reduce the chance of breakage. Because the foam is low density, the X-rays are hardly attenuated by the foam and thus the exposure time is not substantially increased.

Spielman, R.B.

1996-05-21

427

Shielded serpentine traveling wave tube deflection structure  

SciTech Connect

A shielded serpentine slow wave deflection structure (10) having a serpene signal conductor (12) within a channel groove (46). The channel groove (46) is formed by a serpentine channel (20) in a trough plate (18) and a ground plane (14). The serpentine signal conductor (12) is supported at its ends by coaxial feed through connectors 28. A beam interaction trough (22) intersects the channel groove (46) to form a plurality of beam interaction regions (56) wherein an electron beam (54) may be deflected relative to the serpentine signal conductor (12).

Hudson, Charles L. (Santa Barbara, CA); Spector, Jerome (Berkeley, CA)

1994-01-01

428

Interstitial rotating shield brachytherapy for prostate cancer  

SciTech Connect

Purpose: To present a novel needle, catheter, and radiation source system for interstitial rotating shield brachytherapy (I-RSBT) of the prostate. I-RSBT is a promising technique for reducing urethra, rectum, and bladder dose relative to conventional interstitial high-dose-rate brachytherapy (HDR-BT). Methods: A wire-mounted 62 GBq{sup 153}Gd source is proposed with an encapsulated diameter of 0.59 mm, active diameter of 0.44 mm, and active length of 10 mm. A concept model I-RSBT needle/catheter pair was constructed using concentric 50 and 75 ?m thick nickel-titanium alloy (nitinol) tubes. The needle is 16-gauge (1.651 mm) in outer diameter and the catheter contains a 535 ?m thick platinum shield. I-RSBT and conventional HDR-BT treatment plans for a prostate cancer patient were generated based on Monte Carlo dose calculations. In order to minimize urethral dose, urethral dose gradient volumes within 0–5 mm of the urethra surface were allowed to receive doses less than the prescribed dose of 100%. Results: The platinum shield reduced the dose rate on the shielded side of the source at 1 cm off-axis to 6.4% of the dose rate on the unshielded side. For the case considered, for the same minimum dose to the hottest 98% of the clinical target volume (D{sub 98%}), I-RSBT reduced urethral D{sub 0.1cc} below that of conventional HDR-BT by 29%, 33%, 38%, and 44% for urethral dose gradient volumes within 0, 1, 3, and 5 mm of the urethra surface, respectively. Percentages are expressed relative to the prescription dose of 100%. For the case considered, for the same urethral dose gradient volumes, rectum D{sub 1cc} was reduced by 7%, 6%, 6%, and 6%, respectively, and bladder D{sub 1cc} was reduced by 4%, 5%, 5%, and 6%, respectively. Treatment time to deliver 20 Gy with I-RSBT was 154 min with ten 62 GBq {sup 153}Gd sources. Conclusions: For the case considered, the proposed{sup 153}Gd-based I-RSBT system has the potential to lower the urethral dose relative to HDR-BT by 29%–44% if the clinician allows a urethral dose gradient volume of 0–5 mm around the urethra to receive a dose below the prescription. A multisource approach is necessary in order to deliver the proposed {sup 153}Gd-based I-RSBT technique in reasonable treatment times.

Adams, Quentin E., E-mail: quentin-adams@uiowa.edu; Xu, Jinghzu; Breitbach, Elizabeth K.; Li, Xing; Rockey, William R.; Kim, Yusung; Wu, Xiaodong; Flynn, Ryan T. [Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242 (United States)] [Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242 (United States); Enger, Shirin A. [Medical Physics Unit, McGill University, 1650 Cedar Ave, Montreal, Quebec H3G 1A4 (Canada)] [Medical Physics Unit, McGill University, 1650 Cedar Ave, Montreal, Quebec H3G 1A4 (Canada)

2014-05-15

429

CHESS upgrade 1995: Improved radiation shielding (abstract)  

NASA Astrophysics Data System (ADS)

The Cornell Electron Storage Ring (CESR) stores electrons and positrons at 5.3 GeV for the production and study of B mesons, and, in addition, it supplies synchrotron radiation for CHESS. The machine has been upgraded for 300 mA operation. It is planned that each beam will be injected in about 5 minutes and that particle beam lifetimes will be several hours. In a cooperative effort, staff members at CHESS and LNS have studied sources in CESR that produce radiation in the user areas. The group has been responsible for the development and realization of new tunnel shielding walls that provide a level of radiation protection from 20 to ?100 times what was previously available. Our experience has indicated that a major contribution to the environmental radiation is not from photons, but results from neutrons that are generated by particle beam loss in the ring. Neutrons are stopped by inelastic scattering and absorption in thick materials such as heavy concrete. The design for the upgraded walls, the development of a mix for our heavy concrete, and all the concrete casting was done by CHESS and LNS personnel. The concrete incorporates a new material for this application, one that has yielded a significant cost saving in the production of over 200 tons of new wall sections. The material is an artificially enriched iron oxide pellet manufactured in vast quantities from hematite ore for the steel-making industry. Its material and chemical properties (iron and impurity content, strength, size and uniformity) make it an excellent substitute for high grade Brazilian ore, which is commonly used as heavy aggregate in radiation shielding. Its cost is about a third that of the natural ore. The concrete has excellent workability, a 28 day compressive strength exceeding 6000 psi and a density of 220 lbs/cu.ft (3.5 gr/cc). The density is limited by an interesting property of the pellets that is motivated by efficiency in the steel-making application. The pellets are made to be porous, with about 28% of the volume consisting of connected pores of size typically from 1-10 microns. The porosity may have some useful implications for neutron radiation shielding including the possibility of holding a lot more water than a conventional mix, and the opportunity to impregnate the pellets with a good neutron absorber such as boron. This paper will discuss these developments and report the latest results on the effectiveness of the upgraded shielding at Cornell.

Finkelstein, K. D.

1996-09-01

430

Nutrient Shielding in Clusters of Cells  

E-print Network

Cellular nutrient consumption is influenced by both the nutrient uptake kinetics of an individual cell and the cells' spatial arrangement. Large cell clusters or colonies have inhibited growth at the cluster's center due to the shielding of nutrients by the cells closer to the surface. We develop an effective medium theory that predicts a thickness $\\ell$ of the outer shell of cells in the cluster that receives enough nutrient to grow. The cells are treated as partially absorbing identical spherical nutrient sinks, and we identify a dimensionless parameter $\

Lavrentovich, Maxim O; Nelson, David R

2013-01-01

431

Ablative heat shield design for space shuttle  

NASA Technical Reports Server (NTRS)

Ablator heat shield configuration optimization studies were conducted for the orbiter. Ablator and reusable surface insulation (RSI) trajectories for design studies were shaped to take advantage of the low conductance of ceramic RSI and high temperature capability of ablators. Comparative weights were established for the RSI system and for direct bond and mechanically attached ablator systems. Ablator system costs were determined for fabrication, installation and refurbishment. Cost penalties were assigned for payload weight penalties, if any. The direct bond ablator is lowest in weight and cost. A mechanically attached ablator using a magnesium subpanel is highly competitive for both weight and cost.

Seiferth, R. W.

1973-01-01

432

Polyethylene/Boron Composites for Radiation Shielding Applications  

SciTech Connect

Multifunctional composites made with boron are absorbers of low energy nuetrons, and could be used for structural shielding materials. Polyethylene/boron carbide composites were fabricated using conventional polymer processing techniques, and were evaluated for mechanical and radiation shielding properties. Addition of neat boron carbide (powder and nanoparticles) to an injection molding grade HPDE showed superior mechanical properties compared to neat HDPE. Radiation shielding measurements of a 2 wt% boron carbide composite were improved over those of the neat polyethylene.

Harrison, Courtney; Grulke, Eric [Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506 (United States); Burgett, Eric; Hertel, Nolan [Neely Nuclear Research Center, Georgia Institute of Technology, Atlanta, GA 30332 (United States)

2008-01-21

433

Methods and Procedures for Shielding Analyses for the SNS  

SciTech Connect

In order to provide radiologically safe Spallation Neutron Source operation, shielding analyses are performed according to Oak Ridge National Laboratory internal regulations and to comply with the Code of Federal Regulations. An overview of on-going shielding work for the accelerator facility and neutrons beam lines, methods, used for the analyses, and associated procedures and regulations is presented. Methods used to perform shielding analyses are described as well.

Gallmeier, Franz X [ORNL] [ORNL; Iverson, Erik B [ORNL] [ORNL; Remec, Igor [ORNL] [ORNL; Lu, Wei [ORNL] [ORNL; Popova, Irina [ORNL] [ORNL

2014-01-01

434

Buildup factor formulae for multi-layer shields  

Microsoft Academic Search

A formula that gives buildup factors for two-layered shields has been developed. Gamma-ray absorption buildup factors for infinite medium single materials and two- layer shields have been computed using the Monte Carlo Neutral-Particle Transport Code System (MCNP). The source used in the calculations for single and two-layer shields was point isotropic with the energies from 0.1 MeV to 10 MeV.

Mevlut Guvendik

1999-01-01

435

EBT-P gamma-ray shielding system  

Microsoft Academic Search

An elaborate study was carried out for the coil and biological shield of the ELMO Bumpy Torus proof-of-principle (EBT-P) device. A three-dimensional scoping study for the coil shield was performed for four different shielding options to define the heat load for each component and check the compliance with the design criterion of 10 watts maximum heat per coil from the

Gohar

1981-01-01

436

Formulas Giving Buildup Factor for Double-Layered Shields  

Microsoft Academic Search

Formulas that give absorbed dose buildup factors for two-layered shields have been developed based on gamma-ray absorption buildup factors computed with the Monte Carlo Neutral Particle Transport Code System (MCNP). The shielding materials considered were water, lead, steel, concrete, and some of their combinations for two-layered shields with thicknesses between 1 to 10 mfp. Gamma energy considered ranged from 0.5

Mevlut Guvendik; Nicholas Tsoulfanidis

2000-01-01

437

Polyethylene/Boron Composites for Radiation Shielding Applications  

NASA Astrophysics Data System (ADS)

Multifunctional composites made with boron are absorbers of low energy nuetrons, and could be used for structural shielding materials. Polyethylene/boron carbide composites were fabricated using conventional polymer processing techniques, and were evaluated for mechanical and radiation shielding properties. Addition of neat boron carbide (powder and nanoparticles) to an injection molding grade HPDE showed superior mechanical properties compared to neat HDPE. Radiation shielding measurements of a 2 wt% boron carbide composite were improved over those of the neat polyethylene.

Harrison, Courtney; Burgett, Eric; Hertel, Nolan; Grulke, Eric

2008-01-01

438

5. VIEW OF INTERIOR OF BUILDING 220, DECORATIVE FLOOR AT ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. VIEW OF INTERIOR OF BUILDING 220, DECORATIVE FLOOR AT ENTRANCE. VINYL TILE INLAID FLOOR WITH A RED BACKGROUND, GREEN EMBLEM, BROWN AND WHITE EAGLE, RED AND WHITE SHIELD, BLACK ANCHOR, RED ARROWS AND LETTERING. - U.S. Naval Base, Pearl Harbor, Brig, Neville Way near Ninth Street at Marine Barracks, Pearl City, Honolulu County, HI

439

Building Technology  

NSDL National Science Digital Library

From residential houses to hundred-story skyscrapers, many different technologies come together to make a building safe and comfortable. Building design is a continually changing industry, and new advances are being made possible as research progresses.Sustainable development is gaining popularity worldwide in an effort to minimize environmental impact. The Center for Resourceful Building Technology (1) maintains an online guide that describes building practices that are resource-efficient; some information on the center's research projects is also available. Similar in topic is this report from the National Association of Home Builders Research Center (2). The 70-page document is the final report of an April 2003 conference on green building; it gives day-by-day summaries of presentations and activities in which the conference participants were involved. Office buildings have a number of design issues that need to be considered to make a productive work environment. One such issue is the acoustics in a cubicle workspace. The Canadian Institute for Research in Construction (3) discusses some design factors that can improve privacy even in the very open atmosphere of closely spaced cubicles. In the wake of the 2001 anthrax scare, a research project at Pennsylvania State University has garnered significant attention. This paper (4) introduces immune buildings, which have advanced ventilation and air filtration systems that can mitigate the danger caused by airborne pathogens. Experimental results from the project are also presented. The US Department of Energy High Performance Building Initiative (5) is investigating new technologies to make commercial buildings more comfortable and cost effective. Several interesting technical papers and introductory reports are given on the initiative's homepage, including a technology road map for high performance buildings. This essay from the June 2003 issue of Constructech Magazine (6) highlights a movement toward integrated control systems for all types of buildings. The author notes that having a unified system that automatically manages security, lighting, energy, and several other building operations can save time and money in the long run. Another article, written by a member of the Partnership for Advanced Technology in Housing (7), discusses building materials and practices that can improve residential installation's resistance to major storms and natural disasters. An example of an area that is using these weather resistant designs is in Florida; the article cites the vulnerability of coastal homes to hurricanes and outlines some efforts to build them in a more structurally sound manner. Lastly, the Commercial Modular Construction Magazine (8) is a quarterly publication that centers on permanent and temporary modular building design. The second issue of 2003 has, among other things, a good article that describes the basics and benefits of modular construction.

Leske, Cavin.

440

Mothers modify eggs into shields to protect offspring from parasitism  

PubMed Central

Eggs are an immobile, vulnerable stage of development and their success often depends on the oviposition decisions of the mother. Studies show that female animals, and sometimes males, may invest parental resources in order to increase the survival of their offspring. Here, we describe a unique form of parental investment in offspring survival. The seed beetle Mimosestes amicus may lay eggs singly, or may cover eggs with additional egg(s). This egg stacking serves to significantly reduce the mortality of the protected egg from parasitism by the parasitic wasp, Uscana semifumipennis. The smaller top eggs serve only as protective shields; they are inviable, and wasps that develop in them suffer negative fitness consequences. Further, we found egg stacking to be inducible; M. amicus increase the number of stacks they lay when parasitoids are present. However, stacking invokes a cost. When wasps are absent, beetles lay more single eggs, and produce more offspring, highlighting the adaptive value of this extraordinary example of behavioural plasticity in parental investment. PMID:21920977

Deas, Joseph B.; Hunter, Martha S.

2012-01-01

441

Optimum structure of Whipple shield against hypervelocity impact  

NASA Astrophysics Data System (ADS)

Hypervelocity impact of a spherical aluminum projectile onto two spaced aluminum plates (Whipple shield) was simulated to estimate an optimum structure. The Smooth Particle Hydrodynamics (SPH) code which has a unique migration scheme from a rectangular coordinate to an axisymmetic coordinate was used. The ratio of the front plate thickness to sphere diameter varied from 0.06 to 0.48. The impact velocities considered here were 6.7 km/s. This is the procedure we explored. To guarantee the early stage simulation, the shapes of debris clouds were first compared with the previous experimental pictures, indicating a good agreement. Next, the debris cloud expansion angle was predicted and it shows a maximum value of 23 degree for thickness ratio of front bumper to sphere diameter of 0.23. A critical sphere diameter causing failure of rear wall was also examined while keeping the total thickness of two plates constant. There exists an optimum thickness ratio of front bumper to rear wall, which is identified as a function of the size combination of the impacting body, front and rear plates. The debris cloud expansion-correlated-optimum thickness ratio study provides a good insight on the hypervelocity impact onto spaced target system.

Lee, M.

2014-05-01

442

Active Neutron Veto Shield Design for SuperCDMS-SNOLAB  

NASA Astrophysics Data System (ADS)

Protection against neutron backgrounds is one of the key issues for the next generation SuperCDMS direct dark matter detection experiment that aims at exploring the 10-46 cm^2 cross section region for spin-independent interactions of Weakly Interacting Massive Particles (WIMPs) with nucleons. Estimation of the background from radioactive processes is a crucial task for the current experiment stage and for designing future large-scale detectors. An active neutron veto would make the next generation of dark matter experiment more robust, improving the credibility of a dark matter detection claim based on the observation of a few recoil events. SuperCDMS is investigating the feasibility of adding a liquid scintillator active neutron veto, loaded with high neutron capture cross section isotopes, to the SuperCDMS SNOLAB shield design. This system not only will allow us to reject neutron-induced backgrounds, but also will provide an in-situ measurement of the neutron flux near the detector. I will report the status of ongoing studies related to the design and construction of such a veto.

Qiu, Hang

2013-04-01

443

Review of previous shield analysis for space reactors  

NASA Astrophysics Data System (ADS)

In the ten years that have elapsed since serious space shielding work was conducted, major changes in the external environment have occurred. The stronger need for conducting civilian and military operations in space will require both higher power and greater radiation shielding. The concomitant need for weight optimization as well as thermal and stress analysis will offer a significant challenge at today's higher power requirements (100 kWe to multi-MW). This paper reviews previous shielding work for space reactors, focuses on neutronic analysis, thermal and stress analysis, and assesses the performance of lithium hydride and tungsten shields.

Barattino, W. J.; El-Genk, M. S.; Voss, S. S.

444

Graphene shield enhanced photocathodes and methods for making the same  

DOEpatents

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.

Moody, Nathan Andrew

2014-09-02

445

Gravity Scaling of a Power Reactor Water Shield  

NASA Technical Reports Server (NTRS)

Water based reactor shielding is being considered as an affordable option for use on initial lunar surface power systems. Heat dissipation in the shield from nuclear sources must be rejected by an auxiliary thermal hydraulic cooling system. The mechanism for transferring heat through the shield is natural convection between the core surface and an array of thermosyphon radiator elements. Natural convection in a 100 kWt lunar surface reactor shield design has been previously evaluated at lower power levels (Pearson, 2007). The current baseline assumes that 5.5 kW are dissipated in the water shield, the preponderance on the core surface, but with some volumetric heating in the naturally circulating water as well. This power is rejected by a radiator located above the shield with a surface temperature of 370 K. A similarity analysis on a water-based reactor shield is presented examining the effect of gravity on free convection between a radiation shield inner vessel and a radiation shield outer vessel boundaries. Two approaches established similarity: 1) direct scaling of Rayleigh number equates gravity-surface heat flux products, 2) temperature difference between the wall and thermal boundary layer held constant on Earth and the Moon. Nussult number for natural convection (laminar and turbulent) is assumed of form Nu = CRa(sup n). These combined results estimate similarity conditions under Earth and Lunar gravities. The influence of reduced gravity on the performance of thermosyphon heat pipes is also examined.

Reid, Robert S.; Pearson, J. Boise

2008-01-01

446

Remediation of the site of a former active handling building at UKAEA Winfrith  

Microsoft Academic Search

Available in abstract form only. Full text of publication follows: Since July 2000, NUKEM Limited has been carrying out the decommissioning of the former Active Handling Building, A59 at Winfrith, Dorset, United Kingdom (UK) under contract from the nuclear site licence holder, United Kingdom Atomic Energy Authority, (UKAEA). The building contained two heavily shielded suites of caves originally used to

Jack Armitage; Nick Brown; Rowland Cornell; Gareth Jessop

2007-01-01

447

Technique for high axial shielding factor performance of large-scale, thin, open-ended, cylindrical Metglas magnetic shields.  

PubMed

Metglas 2705M is a low-cost commercially available, high-permeability cobalt-based magnetic alloy, provided as a 5.08-cm wide and 20.3-?m thick ribbon foil. We present an optimized construction technique for single-shell, large-scale (human-size), thin, open-ended cylindrical Metglas magnetic shields. The measured dc axial and transverse magnetic shielding factors of our 0.61-m diameter and 1.83-m long shields in the Earth's magnetic field were 267 and 1500, for material thicknesses of only 122 ?m (i.e., 6 foil layers). The axial shielding performance of our single-shell Metglas magnetic shields, obtained without the use of magnetic shaking techniques, is comparable to the performance of significantly thicker, multiple-shell, open-ended Metglas magnetic shields in comparable-magnitude, low-frequency applied external fields reported previously in the literature. PMID:21806224

Malkowski, S; Adhikari, R; Hona, B; Mattie, C; Woods, D; Yan, H; Plaster, B

2011-07-01

448

Control System Commissioning for Enhanced Building Operations  

E-print Network

This paper highlights the import role control systems play in the operation of modern buildings and describes ways to improve the final stage of commissioning. We also describe practical issues associated with modern IT-oriented control systems...

Salsbury, T. I.; Singhal, A.

2003-01-01

449

Learning Buildings.  

ERIC Educational Resources Information Center

This publication, from a non-profit organization in Britain concerned with educational facilities design, aims to stimulate a debate about the building environment of secondary schools in relation to other dimensions--people, the learning process, and the institutional framework. Its chapters are: (1) "School Buildings in Britain Today"; (2)…

Annesley, Barbara; Horne, Matthew; Cottam, Hilary

450

Gas Shielding Technology for Welding and Brazing  

NASA Technical Reports Server (NTRS)

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."

Nunes, Arthur J.; Gradl, Paul R.

2012-01-01

451

Twin jet shielding. [for aircraft noise reduction  

NASA Technical Reports Server (NTRS)

For an over-the-wing/under-the-wing engine configuration on an airplane, the noise produced by the upper jet flow is partially reflected by the lower jet. An analysis has been performed which can be used to predict the distribution of perceived noise levels along the ground plane at take-off for an airplane which is designed to take advantage of the over/under shielding concept. Typical contours of PNL, the shielding benefit in the shadow zone, and the EPNL values at 3.5 nautical miles from brake release as well as EPNL values at sideline at 0.35 nautical miles have been calculated. This has been done for a range of flow parameters characteristic of engines producing inverted velocity profile jets suitable for use in a supersonic cruise vehicle. Reductions up to 6.0 EPNdB in community noise levels can be realized when the over engines are operated at higher thrust and the lower engines simultaneously operated with reduced thrust keeping the total thrust constant.

Parthasarathy, S. P.; Cuffel, R. F.; Massier, P. F.

1979-01-01

452

MicroShield/ISOCS gamma modeling comparison.  

SciTech Connect

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 Canberra's 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.

Sansone, Kenneth R

2013-08-01

453

Heat flow from the Liberian precambrian shield  

SciTech Connect

Uncorrected heat flow in iron formation rocks from three areas within the Liberian part of the West African Shield ranges from 50 to more than 80 mW m/sup -2/. When corrections are applied for topography and refraction, the range of heat flow is narrowed to between 38 and 42 mW m/sup -2/. In comparison with heat flows from other parts of the West African Craton, these values are consistent with preliminary results from Ghana (42 +- 8 mW m/sup -2/) and Nigeria (38 +- 2 mW /sup -2/) but are somewhat higher than values from Niger (20 mW m/sup -2/) and neighboring Sierra Leone (26 mW m/sup -2/). The Liberian values are significantly lower than the heat flow offshore in the equatorial Atlantic Ocean (58 +- 8 mW m/sup -2/), suggesting large lateral temperature gradients within the lithosphere near the coast. Values of heat production from outcrops of crystalline basement rocks near the holes are between 2 and 2.3 ..mu..W m/sup -3/. A heat-flow/heat-production relation cannot be established because of the small range of values; however, assuming a 'characteristic depth' of 8 km (similar to the North American Craton) the reduced heat flow of from 20 to 25 mW m/sup -2/ is consistent with that from other Precambrian shields.

Sass, J.H.; Behrendt, J.C.

1980-06-10

454

Liquid Vortex Shielding for Fusion Energy Applications  

SciTech Connect

Swirling liquid vortices can be used in fusion chambers to protect their first walls and critical elements from the harmful conditions resulting from fusion reactions. The beam tube structures in heavy ion fusion (HIF) must be shielded from high energy particles, such as neutrons, x-rays and vaporized coolant, that will cause damage. Here an annular wall jet, or vortex tube, is proposed for shielding and is generated by injecting liquid tangent to the inner surface of the tube both azimuthally and axially. Its effectiveness is closely related to the vortex tube flow properties. 3-D particle image velocimetry (PIV) is being conducted to precisely characterize its turbulent structure. The concept of annular vortex flow can be extended to a larger scale to serve as a liquid blanket for other inertial fusion and even magnetic fusion systems. For this purpose a periodic arrangement of injection and suction holes around the chamber circumference are used, generating the layer. Because it is important to match the index of refraction of the fluid with the tube material for optical measurement like PIV, a low viscosity mineral oil was identified and used that can also be employed to do scaled experiments of molten salts at high temperature.

Bardet, Philippe M. [University of California, Berkeley (United States); Supiot, Boris F. [University of California, Berkeley (United States); Peterson, Per F. [University of California, Berkeley (United States); Savas, Oemer [University of California, Berkeley (United States)

2005-05-15

455

Shielding Design for the CARIBU Project  

NASA Astrophysics Data System (ADS)

The CAlifornium Radioactive Ion Breeder Upgrade (CARIBU) [1] will serve as a source of radioactive ions to be accelerated by the ATLAS accelerator [2]. CARIBU will consist of an open, 1 Ci Cf-252 source electroplated on a Ta backing. Fission fragments emitted from the source will be captured in a He gas cell with DC and RF fields that will direct the radioactive ions toward the exit nozzle. The ions will be mass analyzed and transported to a charge breeding ECR source and injected into ATLAS. The radiation fields produced by an unshielded 1 Ci Cf-252 source exceed 4 rem/hr (neutron), and 250 mR/hr (gamma) at 1 meter. In order to allow unlimited access to the CARIBU source area, we are designing a shielding system to reduce the radiation fields to ˜1 mrem/hr at 30 cm from accessible surfaces. The MCNPX code [3] is being used to model the neutron and gamma radiation shielding. The results of the simulations and some comparisons with measurements will be presented. REFERENCES [1] www.phy.anl.gov/atlas/caribu.html [2] www.phy.anl.gov/atlas/index.html [3] mcnpx.lanl.gov/.

Moore, Eugene; Baker, Samuel; Pardo, Richard; Savard, Guy

2006-10-01

456

Building Green  

NSDL National Science Digital Library

There's a great deal of talk about "building green" in the architecture and design world, but to many, this phrase may not mean a great deal. This website, created by the Building Green company, can help the uninitiated learn more about this subject. First-time visitors should click on the "Green Building Information" area. Here they can get answers to such question as "What is green?" and also learn more about green design strategies and the LEED rating system. Right next to this section is the "Case Studies" area, which features green building projects like elementary schools, commercial facilities, and university buildings. The site is rounded out by a "News" area and a detailed bibliography of websites, print resources, and so on.

457

Application of a dummy eye shield for electron treatment planning  

PubMed Central

Metallic eye shields have been widely used for near-eye treatments to protect critical regions, but have never been incorporated into treatment plans because of the unwanted appearance of the metal artifacts on CT images. The purpose of this work was to test the use of an acrylic dummy eye shield as a substitute for a metallic eye shield during CT scans. An acrylic dummy shield of the same size as the tungsten eye shield was machined and CT scanned. The BEAMnrc and the DOSXYZnrc were used for the Monte Carlo (MC) simulation, with the appropriate material information and density for the aluminum cover, steel knob and tungsten body of the eye shield. The Pinnacle adopting the Hogstrom electron pencil-beam algorithm was used for the one-port 6-MeV beam plan after delineation and density override of the metallic parts. The results were confirmed with the metal oxide semiconductor field effect transistor (MOSFET) detectors and the Gafchromic EBT2 film measurements. For both the maximum eyelid dose over the shield and the maximum dose under the shield, the MC results agreed with the EBT2 measurements within 1.7%. For the Pinnacle plan, the maximum dose under the shield agreed with the MC within 0.3%; however, the eyelid dose differed by –19.3%. The adoption of the acrylic dummy eye shield was successful for the treatment plan. However, the Pinnacle pencil-beam algorithm was not sufficient to predict the eyelid dose on the tungsten shield, and more accurate algorithms like MC should be considered for a treatment plan. PMID:22915776

Kang, Sei-Kwon; Park, Soah; Hwang, Taejin; Cheong, Kwang-Ho; Han, Taejin; Kim, Haeyoung; Lee, Me-Yeon; Kim, Kyoung Ju; Oh, Do Hoon; Bae, Hoonsik

2013-01-01

458

Application of a dummy eye shield for electron treatment planning.  

PubMed

Metallic eye shields have been widely used for near-eye treatments to protect critical regions, but have never been incorporated into treatment plans because of the unwanted appearance of the metal artifacts on CT images. The purpose of this work was to test the use of an acrylic dummy eye shield as a substitute for a metallic eye shield during CT scans. An acrylic dummy shield of the same size as the tungsten eye shield was machined and CT scanned. The BEAMnrc and the DOSXYZnrc were used for the Monte Carlo (MC) simulation, with the appropriate material information and density for the aluminum cover, steel knob and tungsten body of the eye shield. The Pinnacle adopting the Hogstrom electron pencil-beam algorithm was used for the one-port 6-MeV beam plan after delineation and density override of the metallic parts. The results were confirmed with the metal oxide semiconductor field effect transistor (MOSFET) detectors and the Gafchromic EBT2 film measurements. For both the maximum eyelid dose over the shield and the maximum dose under the shield, the MC results agreed with the EBT2 measurements within 1.7%. For the Pinnacle plan, the maximum dose under the shield agreed with the MC within 0.3%; however, the eyelid dose differed by -19.3%. The adoption of the acrylic dummy eye shield was successful for the treatment plan. However, the Pinnacle pencil-beam algorithm was not sufficient to predict the eyelid dose on the tungsten shield, and more accurate algorithms like MC should be considered for a treatment plan. PMID:22915776

Kang, Sei-Kwon; Park, Soah; Hwang, Taejin; Cheong, Kwang-Ho; Han, Taejin; Kim, Haeyoung; Lee, Me-Yeon; Kim, Kyoung Ju; Oh, Do Hoon; Bae, Hoonsik

2013-01-01

459

Boron isotopic constraints on the source of Hawaiian shield lavas  

NASA Astrophysics Data System (ADS)

Boron isotopic compositions of lavas from three representative Hawaiian shield volcanoes (Kilauea, Mauna Loa, and Koolau) were analyzed by thermal ionization mass spectrometry. The boron isotopic composition of each sample was analyzed twice, once with and once without acid leaching to evaluate the effect of posteruptive boron contamination. Our acid-leaching procedure dissolved glass, olivine, secondary zeolite, and adsorbed boron; this dissolved boron was completely removed from the residue, which was comprised of plagioclase, pyroxenes, and newly formed amorphous silica. We confirmed that an appropriate acid-leaching process can eliminate adsorbed and incorporated boron contamination from all submarine samples without modifying the original 11B/ 10B ratio. On the other hand, when the sample was weathered, i.e., the olivine had an iddingsite rim, 11B/ 10B of the acid-resistant minerals are also modified, thus it is impossible to get the preeruptive 11B/ 10B value from the weathered samples. Through this elimination and evaluation procedure of posteruptive contamination, preeruptive ? 11B values for the shield lavas are -4.5 to -5.4‰ for Koolau ( N = 8), -3.6 to -4.6‰ for Kilauea ( N = 11), and -3.0 to -3.8‰ for Mauna Loa ( N = 6). Historical Kilauea lavas show a systematic temporal trend for B content and Nb/B coupled with other radiogenic isotopic ratios and trace element ratios, at constant ? 11B, indicating little or no assimilation of crustal materials in these lavas. Uncorrelated B content and ? 11B in Koolau and Mauna Loa lavas may also indicate little or no effect of crustal assimilation in these lavas. The source of KEA-component (identical to the so-called Kea end member in Hawaiian lavas) of the Hawaiian source mantle, represented by Kilauea, should be derived from lower part of subducted oceanic crust or refractory peridotite in the recycled subducted slab. The systematic trend from Kilauea to Koolau—decreasing ? 11B coupled with decreasing ?Nd as well as increasing 87Sr/ 86Sr and 206Pb/ 204Pb—is consistent with involvement of subducted sediment components in the EMK(enriched Makapuu)-component, represented by Makapuu-stage of Koolau lavas.

Tanaka, Ryoji; Nakamura, Eizo

2005-07-01

460

Can Youth Sport Build Character?  

ERIC Educational Resources Information Center

Participation and competition in some sports are associated with lower stages of moral reasoning. Coaches can foster moral development by starting with the right mental model, holding benchmark meetings about team values, setting goals for physical and character skills, making time for guided discussion sessions, building community, modeling…

Shields, David Light; Bredemeier, Brenda Light; Power, F. Clark

2001-01-01

461

Building Big  

NSDL National Science Digital Library

Building Big is a very informative site about the engineering principles required to build large structures, including bridges, domes, skyscrapers, dams, and tunnels. The interactive labs presented on the site discuss the various factors (e.g. forces, materials, loads, shapes) that need to be considered when designing large buildings. Fun challenges test these concepts for each of the five structures by putting students in charge of various construction projects. The student needs to weigh the pros and cons of particular designs and choose which is best for a given scenario. There are also many interviews with different structural engineers that will help students understand what working in this field is like.

462

Intelligent Buildings  

SciTech Connect

The topic of "intelligent buildings" (IBs) emerged in the early 1980s. Since, the term has been used to represent a variety of related, yet differing topics, each with a slightly different focus and purpose. Wiring and networking-infrastructure companies emphasize the cabling requirements for communication in intelligent buildings and the need to accommodate future needs for higher-speed broadband. Lucent (Lucent 2000) for example, defines an IB as "...one with a completely integrated wiring architecture. A single cabling system that handles all information traffic - voice, data, video, even the big building management systems."

Brambley, Michael R.; Armstrong, Peter R.; Kintner-Meyer, Michael CW; Pratt, Robert G.; Katipamula, Srinivas

2001-01-01

463

Building Molecules  

NSDL National Science Digital Library

This online interactive has three activities in the NanoLab (press the upper right button): Build, Zoom, and Transform. In Build, learners build increasingly complex molecules out of carbon, oxygen, and hydrogen, and is useful for connecting subscripts and the number of atoms, and for introducing 3D molecular structures which are automatically built. Zoom is a "powers of 10" zoom-in ranging from 10,000 kilometers to 1 nanometer. Transform is a simulation of water changing phase from solid to liquid to gas. Through exploration of the site learners form a better understanding of the composition of matter.

Rensselaer Polytechnic In