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1

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

2

4. Sac shield at entry of command center, building 501, ...  

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

4. Sac shield at entry of command center, building 501, looking west - Offutt Air Force Base, Strategic Air Command Headquarters & Command Center, Command Center, 901 SAC Boulevard, Bellevue, Sarpy County, NE

3

Koolau shield basalt as xenoliths entrained during rejuvenated-stage eruptions: perspectives on magma mixing  

Microsoft Academic Search

Rejuvenated-stage tuff cones (Honolulu Volcanics) on Koolau volcano, Oahu, Hawaii, contain xenoliths of Koolau shield basalt. Because Koolau subaerial shield lavas represent a Hawaiian geochemical 'end member', and submarine shield lavas have compositions with some affinities to Mauna Loa and Kilauea, we analyzed 28 xenolithic basalts from Salt Lake and Koko Head cones to determine how these seemingly random samplings

J. P. Weinstein; R. V. Fodor; G. R. Bauer

2004-01-01

4

Late-stage summit activity of Martian shield volcanoes  

NASA Technical Reports Server (NTRS)

The preservation of morphologically fresh lava flows which pre-date the most recent episodes of caldera collapse at the summits of Ascraeus, Arsia and Olympus Montes indicates that explosive eruptions were not associated with this stage of Tharsis shield volcanism. The existence of resurfaced floor segments, complex wrinkle ridges, and lava terraces within the summit craters suggests that lava lakes comprised the dominant form of the intra-caldera activity. Multiple collapse episodes on Ascraeus and Olympus Montes are indicated by the nested summit craters. The most plausible cause of caldera collapse appears to be large-scale sub-terminal effusive activity, which is corroborated by the previously recognized existence of large lava flows on the flanks of these volcanoes. Due to the implied sequence of large-scale explosive (silicic) volcanism followed by effusive (basaltic) activity, it appears highly unlikely that ignimbrites or other forms of pyroclastic flows (previously proposed as possible deposits within the Olympus Mons aureole material) were ever erupted from the Tharsis Montes.

Mouginis-Mark, P. J.

1982-01-01

5

VLA-VLBA Interference Protection Memo #37 VLBA-PT Station Building Shielding Test Report  

E-print Network

diagram, taken from VLBA Array Memo #596 is presented as Figure 1. The VLBA-PT station building shieldingpg. 1 VLA-VLBA Interference Protection Memo #37 VLBA-PT Station Building Shielding Test Report Dan Mertely, Charlie Barham 20090602 Abstract Measurements of the VLBA-PT station building shielding from 3

Groppi, Christopher

6

Three-dimensional analysis of AP600 standard plant shield building roof  

Microsoft Academic Search

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

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

1999-01-01

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

Geochemistry of Kauai shield-stage lavas: Implications for the chemical evolution of the Hawaiian plume  

Microsoft Academic Search

We measured He, Sr, Nd, Pb, and Os isotope ratios and major and trace element concentrations in stratigraphically and paleomagnetically controlled shield-stage lavas from Kauai, Hawaii. The range of 3He\\/4He ratios (17-28 RA) from Kauai is similar to that reported from Loihi and thus challenges the prevailing notion that high 3He\\/4He ratios are restricted to the preshield stage of Hawaiian

S. Mukhopadhyay; J. C. Lassiter; K. A. Farley; S. W. Bogue

2003-01-01

9

Geochemistry of Kauai shield-stage lavas: Implications for the chemical evolution of the Hawaiian plume  

Microsoft Academic Search

We measured He, Sr, Nd, Pb, and Os isotope ratios and major and trace element concentrations in stratigraphically and paleomagnetically controlled shield-stage lavas from Kauai, Hawaii. The range of 3He\\/4He ratios (17–28 RA) from Kauai is similar to that reported from Loihi and thus challenges the prevailing notion that high 3He\\/4He ratios are restricted to the preshield stage of Hawaiian

S. Mukhopadhyay; J. C. Lassiter; K. A. Farley; S. W. Bogue

2003-01-01

10

PLUG STORAGE BUILDING, TRA611, AWAITS SHIELDING SOIL TO BE PLACED ...  

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

PLUG STORAGE BUILDING, TRA-611, AWAITS SHIELDING SOIL TO BE PLACED OVER PLUG STORAGE TUBES. WING WALLS WILL SUPPORT EARTH FILL. MTR, PROCESS WATER BUILDING, AND WORKING RESERVOIR IN VIEW BEYOND PLUG STORAGE. CAMERA FACES NORTHEAST. INL NEGATIVE NO. 2949. Unknown Photographer, 7/30/1951 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

11

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

12

LPT. Shield test facility assembly and test building (TAN646), south ...  

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

LPT. Shield test facility assembly and test building (TAN-646), south end of EBOR helium wing. Camera facing north. Monorail protrudes from upper-level door. Rust marks on concrete wall are from stack. Metal shed is post-1970 addition. INEEL negative no. HD-40-8-1 - 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

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

15

Geochemistry of Kauai shield-stage lavas: Implications for the chemical evolution  

E-print Network

shield and is present in varying proportion in other Hawaiian shield volcanoes. Shield lavas from Kauai of volcanism from west to east, or alternatively east and west Kauai are two distinct shield volcanoes. In the latter case, the two shield volcanoes have maintained distinct magma supply sources and plumbing systems

Mukhopadhyay, Sujoy

16

Assessing office building life cycle costs at preliminary design stage  

Microsoft Academic Search

This paper details the development of a quantitative life cycle costing model and software for the assessment of financial feasibility of office building projects at the preliminary design stage. The model handles most technical data and financial factors which are required to determine the life cycle costs and economic feasibility of proposed buildings, with basic, minimum input. Three assessment factors

A. C. Khanduri; C. Bédard; S. Alkass

1996-01-01

17

Tectonic-magmatic stages of shield evolution: the Pan-African belt in northeastern Egypt  

NASA Astrophysics Data System (ADS)

The Arabian-Nubian shield illustrates an example of plate tectonics during the Pan-African orogenic event (ca. 950-550 Ma); it is considered one of the most remarkable Proterozoic shield areas yet known. Although there is now a general agreement that the shield has evolved by a series of magmatic arcs and terrain accretion, the evolution of its northernmost part exposed in northeastern Egypt remains controversial. Two contrasting tectonic models have been proposed for the evolution of this region: regional crustal extension and magmatic-arc regimes. There is no convincing evidence of older (Archean) sialic materials within the region, although the region is flanked by Archean crust. The Neoproterozoic crustal components exposed in northeastern Egypt preserve a record for its evolution. A large gabbro-diorite-tonalite complex (GDT, 881 Ma) emplaced during the early stage of the Pan-African orogeny is geochemically primitive, exhibits a low initial {87Sr }/{86Sr } ratio (0.704) and shows trace-element characteristics of oceanic-arc-related lavas. The GDT complex was produced (by fractionation) from a mantle-derived tholeiitic magma formed within an island-arc tectonic environment. A synorogenic stage characterized by extensive volcanism that produced the Dokhan volcanic suite (DVS, 620 Ma) forms a continuous basalt to rhyolitic ignimbrite calc-alkaline magma series, exhibiting features of arc-related volcanism, with REE profiles similar overall to Andean andesites and ignimbrites. The Dokhan suite was produced in a continental-arc setting. A granodiorite-adamellite-leucogranite composite batholith (552 Ma) emplaced during the late stage of the Pan-African orogeny exhibits typical features of I-type complexes, trace element traits of volcanic-arc granites, and is also interpreted to have been formed in an Andean-type setting. A trondhjemite pluton was also formed at this late orogenic stage, by partial melting of GDT host rocks at depth. Cooling and relaxation of the newly formed Pan-African crust caused extensive fracturing, which was followed by intrusion of NE-SW- and NNW-SSE-trending dyke swarms at 493 Ma. This episode marks a fundamental inversion from orogenic compressional to anorogenic extensional processes around the Neoproterozoic-Paleozoic boundary. Anorogenic magmatism was locally associated with such extension-induced structures. The Mount Gharib peralkaline granite (476 Ma), for example, exhibits trace element traits of A-type, within-plate granites, and a high initial {87Sr }/{86Sr } ratio (0.711), and was formed in a rift environment. Thus, the region is characterized by lengthy episodes of discontinuous subduction (˜ 880-550 Ma), during which it evolved to form a primitive crust by early Pan-African island arcs and late Pan-African continental arcs. This was followed by an even longer period of crustal extension (˜ 550-90 Ma) that produced localized anorogenic magmatism.

Abdel-Rahman, Abdel-Fattah M.

1995-02-01

18

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

19

SIMULATION-BASED METHOD TO ASSESS BUILDING ENERGY CONSUMPTION LEVEL AT OPERATION STAGE  

Microsoft Academic Search

Energy conservation at building's operation stage is very important for the national economy. Building up reasonable methods to assess building operational energy consumption is critical and necessary. Japanese researchers use CEC (Coefficient of Energy Consumption), which is the ratio of actual energy consumption to ideal energy consumption, to assess building system's operation level. In this paper, a concept of SCEC

Xiaoru Zhou; Yingxin Zhu; Chunhai Xia; Haibo Chen

20

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

21

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

22

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

23

High performance building blocks for wireless receiver: multi-stage amplifiers and low noise amplifiers  

E-print Network

of Committee, Edgar S?nchez-Sinencio Committee Members, C?sar O. Malav? Weiping Shi Jos? Silva-Mart?nez Head of Department, Costas N. Georghiades December 2007 Major Subject: Electrical Engineering iii ABSTRACT High... Performance Building Blocks for Wireless Receiver: Multi-Stage Amplifiers and Low Noise Amplifiers. (December 2007) Xiaohua Fan, B.S., Tsinghua University; M.S., Chinese Academy of Sciences Chair of Advisory Committee: Dr. Edgar S...

Fan, Xiaohua

2009-05-15

24

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

25

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

26

Early stage design decisions: the way to achieve sustainable buildings at lower costs.  

PubMed

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

27

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

Braganca, Luis; Vieira, Susana M.; Andrade, Joana B.

2014-01-01

28

Military Review: Desert Shield/Desert Storm.  

National Technical Information Service (NTIS)

CONTENTS: CASCOM Support for DESERT SHIELD/DESERT STORM; Total Army CSS: Providing the Means for Victory; Logistics Automation Support for Desert Storm; Building the DESERT Logistics force; Depot operations Supporting DESERT SHIELD; The Readiness Group's ...

1991-01-01

29

The shield-backed bug, Pachycoris stallii: Description of immature stages, effect of maternal care on nymphs, and notes on life history  

PubMed Central

The life history of the shield-backed bug, Pachycoris stallii Uhler (Heteroptera: Scutelleridae), immatures was studied on its host plant, Croton californicus Muell.-Arg. (Euphorbiaceae), in Baja California Sur, Mexico. Immature stages are described and illustrated. Pachycoris stallii is bi- or multivoltine and occurs in xeric areas with sandy soil where it is rarely encountered away from C. californicus. Nymphs and adults feed on seeds within C. californicus fruit. Bugs oviposit on the underside of leaves, and females guard their eggs and first-instar nymphs from natural enemies. Embryonic orientation of prolarvae is nonrandom; each embryo is oriented with its venter directed toward the ground. This orientation may facilitate aggregation of first instars. The longitudinal axes of eggs are always oriented upward at about a 16° angle of deviation from a line perpendicular to the leaf surface. This is the first recorded observation of this phenomenon in Pentatomoidea. Experimental removal of females guarding first instars results in 100% loss of nymphs, and this is attributed to disruption of the aggregative behavior of nymphs. Maternal guarding appears to be a net benefit to P. stallii, despite possible costs to the brooding female. PMID:17119611

Williams, Livy; Coscaron, Maria C; Dellape, Pablo M; Roane, Timberley M

2005-01-01

30

The shield-backed bug, Pachycoris stallii: description of immature stages, effect of maternal care on nymphs, and notes on life history.  

PubMed

The life history of the shield-backed bug, Pachycoris stallii Uhler (Heteroptera: Scutelleridae), immatures was studied on its host plant, Croton californicus Muell.-Arg. (Euphorbiaceae), in Baja California Sur, Mexico. Immature stages are described and illustrated. Pachycoris stallii is bi- or multivoltine and occurs in xeric areas with sandy soil where it is rarely encountered away from C. californicus. Nymphs and adults feed on seeds within C. californicus fruit. Bugs oviposit on the underside of leaves, and females guard their eggs and first-instar nymphs from natural enemies. Embryonic orientation of prolarvae is nonrandom; each embryo is oriented with its venter directed toward the ground. This orientation may facilitate aggregation of first instars. The longitudinal axes of eggs are always oriented upward at about a 16 degree angle of deviation from a line perpendicular to the leaf surface. This is the first recorded observation of this phenomenon in Pentatomoidea. Experimental removal of females guarding first instars results in 100% loss of nymphs, and this is attributed to disruption of the aggregative behavior of nymphs. Maternal guarding appears to be a net benefit to P. stallii, despite possible costs to the brooding female. PMID:17119611

Williams, Livy; Coscarón, Maria C; Dellapé, Pablo M; Roane, Timberley M

2005-01-01

31

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

32

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

33

EBT-P gamma ray shielding analysis  

SciTech Connect

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 the performance and cost is discussed. Next, 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 load per coil from the gamma ray sources. Also, a detailed biological dose survey was performed which included: a) the dose equivalent inside and outside the building, b) the dose equivalent from the two mazes of the building, and c) the skyshine contribution to the dose equivalent.

Gohar, Y.

1983-09-01

34

New dose-mortality data based on 3-D radiation shielding calculation for concrete buildings at Nagasaki  

SciTech Connect

The analysis of radiation doses received during the World War II attack on Nagasaki provides an important source of biochemical information. More than 40 years after the war, it has been possible to make a satisfactory calculation of the doses to personnel inside reinforced concrete buildings by use of a 3-dimensional discrete ordinates code, TORT. The results were used to deduce a new value of the LD50 parameter that is in good agreement with traditional values. The new discrete ordinates software appears to have potential application to conventional radiation transport calculations as well. 9 refs., 3 figs., 2 tabs.

Rhoades, W.A.; Childs, R.L.; Ingersoll, D.T.

1988-01-01

35

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

36

Linking between real and virtual spaces: building the Mixed Reality stage environment  

Microsoft Academic Search

This paper is concerned with the concept of a Mixed Reality (MR) stage environment as networked layering of physical space and virtual environments. The MR stage enables multiple performers to interact through intuitive free body interfaces. The goal is the creation of interface environments which allow participants to communicate in shared and remote physical spaces through their natural senses: hearing,

Monika Fleischmann; Wolfgang Strauss

2001-01-01

37

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

38

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

39

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

40

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

41

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).

Hickson, Tom

42

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

43

Chiral shielding  

Microsoft Academic Search

We demonstrate how a chiral soft pion theorem (SPT) shields the scalar meson ground-state isoscalar sigma(600-700) and isospinor kappa(800-900) from detection in a1-->pi(pipi)swave, gammagamma-->2pi0, pi-p-->pi-pi+n and K-p-->K-pi+n processes. While pseudoscalar meson PVV transitions are known to be determined by (only) quark loop diagrams, the above SPT also constrains scalar meson SVV transitions to be governed (only) by meson loop diagrams.

L. Babukhadia; Ya. A. Berdnikov; A. N. Ivanov; M. D. Scadron

2000-01-01

44

Chiral shielding  

Microsoft Academic Search

We demonstrate how a chiral soft pion theorem (SPT) shields the scalar meson ground-state isoscalar Ï(600-700) and isospinor κ(800-900) from detection in aââÏ(ÏÏ){sub swave}, γγâ2Ï°, Ï⁻pâÏ⁻Ï{sup +}n and K⁻pâK⁻Ï{sup +}n processes. While pseudoscalar meson PVV transitions are known to be determined by (only) quark loop diagrams, the above SPT also constrains scalar meson SVV transitions to be governed (only) by

L. Babukhadia; Ya. A. Berdnikov; A. N. Ivanov; M. D. Scadron

2000-01-01

45

Shielding Benchmark Computational Analysis  

SciTech Connect

Over the past several decades, nuclear science has relied on experimental research to verify and validate information about shielding nuclear radiation for a variety of applications. These benchmarks are compared with results from computer code models and are useful for the development of more accurate cross-section libraries, computer code development of radiation transport modeling, and building accurate tests for miniature shielding mockups of new nuclear facilities. When documenting measurements, one must describe many parts of the experimental results to allow a complete computational analysis. Both old and new benchmark experiments, by any definition, must provide a sound basis for modeling more complex geometries required for quality assurance and cost savings in nuclear project development. Benchmarks may involve one or many materials and thicknesses, types of sources, and measurement techniques. In this paper the benchmark experiments of varying complexity are chosen to study the transport properties of some popular materials and thicknesses. These were analyzed using three-dimensional (3-D) models and continuous energy libraries of MCNP4B2, a Monte Carlo code developed at Los Alamos National Laboratory, New Mexico. A shielding benchmark library provided the experimental data and allowed a wide range of choices for source, geometry, and measurement data. The experimental data had often been used in previous analyses by reputable groups such as the Cross Section Evaluation Working Group (CSEWG) and the Organization for Economic Cooperation and Development/Nuclear Energy Agency Nuclear Science Committee (OECD/NEANSC).

Hunter, H.T.; Slater, C.O.; Holland, L.B.; Tracz, G.; Marshall, W.J.; Parsons, J.L.

2000-09-17

46

Shielded Canister Transporter  

SciTech Connect

The Hanford Waste Vitrification Plant (HWVP) will produce canisters filled with high-level radioactive waste immobilized in borosilicate glass. This report discusses a Shielded Canister Transporter (SCT) which will provide the means for safe transportation and handling of the canisters from the Vitrification Building to the Canister Storage Building (CSB). The stainless steel canisters are 0.61 meters in diameter, 3.0 meters tall, and weigh approximately 2,135 kilograms, with a maximum exterior surface dose rate of 90,000 R/hr. The canisters are placed into storage tubes to a maximum of three tall (two for overpack canisters) with an impact limiter placed at the tube bottom and between each canister. A floor plug seals the top of the storage tube at the operating floor level of the CSB.

Eidem, G.G. Jr.; Fages, R.

1993-08-01

47

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

48

Pressure building during the early stages of gas production in a radioactive waste repository  

NASA Astrophysics Data System (ADS)

In a radioactive waste repository, hydrogen may be produced by anoxic corrosion of the metallic components, and by water radiolysis. The design of deep geological repositories presently envisaged in many countries tends to inhibit the migration of every chemical species coming from the repository, by means of several concentric watertight barriers. This tightness, which is desirable for other reasons, might prevent hydrogen evacuation and cause a pressure rise in the near-field. Can this pressure break the barriers? In the first stage of the process, the hydrogen dissolves in the porewater. It is shown in the present paper that in the vicinity of a steel surface embedded in clay, the pressure rise due to the production of dissolved hydrogen may be large already (a few MPa), and may represent a significant fraction of the barrier resistance limit. In the second phase of the process, a gas bubble may form, causing a further pressure increase. The problem of gas production in geological repositories is treated here as a special case of thermo-hydro-chemico-mechanical coupling in a porous medium. The time needed for the bubble to form depends on the nature of the metal, and on the characteristics of the barrier. The purpose of this paper is to give orders of magnitude for the time and space scales associated with hydrogen production in the near-field of a deep repository, before the formation of a gaseous phase. The conditions under which a gas phase forms are also discussed.

Bonin, Bernard; Colin, Michel; Dutfoy, Anne

2000-09-01

49

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

50

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

51

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 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, J.A.; Stone, R.R.; Fabyan, J.

1985-02-12

52

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. 3 figs.

Kerns, J.A.; Stone, R.R.; Fabyan, J.

1987-10-06

53

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

54

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

55

Comparison of DOE-2.1E with Energyplus and TRNSYS for Ground Coupled Residential Buildings in Hot anf Humid Climates Stage 2  

E-print Network

ESL-TR-11-12-09 COMPARISON OF DOE-2.1E WITH ENERGYPLUS AND TRNSYS FOR GROUND COUPLED RESIDENTIAL BUILDINGS IN HOT AND HUMID CLIMATES STAGE 2 “Literature Survey on Comparative Studies on Slab-on-grade and Basement Models of DOE-2, EnergyPlus... ............................................................................................................................. 4 Introduction ................................................................................................................................................... 4 1. Studies that compared DOE-2 with EnergyPlus...

Andolsun, S.; Culp, C.

2011-01-01

56

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

Microsoft Academic Search

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

J. W. Jones; J. J. Deringer; J. D. Hall

1990-01-01

57

Rotating shielded crane system  

SciTech Connect

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

58

Flow-By-Flow Mapping on Fogo, Cape Verde Islands, Reveals Long Term Variations in Eruption Distributions and Volcanic Edifice Structure at a Shield-Stage Oceanic Island Volcano  

NASA Astrophysics Data System (ADS)

Most maps of large oceanic island shield volcanoes show the lava flows and scoria cones of individual historic and subhistoric eruptions as individual units but then resort to grouping older rocks into larger stratigraphic units. This grouping makes it difficult to characterize long-term progressive trends in volumes of individual eruptions and distributions of eruptive vents, but is commonly made necessary by poor exposure, limited compositional variation between individual eruptions, and burial of older by younger volcanic rocks. In contrast, work on Fogo, Cape Verde Islands has involved flow-by-flow mapping of rocks erupted over an extended period of tens of thousands of years, as part of the process of mapping the island and producing a 1:25 000 scale geological map for research and hazard management purposes. Around three-quarters of the island is characterized by low rainfall and limited vegetation cover, with erosion restricted to narrow gullies. Only in small areas on the windward side of the island do higher rainfall, thick vegetation and deeper erosion combine to prevent flow-by-flow mapping. The map of the island is accompanied by a rigorous representation of direct and inferred age relationships between lavas and scoria cones of different eruptions using a novel type of age correlation diagram. The time period covered by the flow-by-flow mapping includes both the final stages of growth of an older shield volcano (Monte Amarelo volcano) prior to its collapse and the subsequent growth of a new volcano (Cha das Caldeiras volcano). The latter forms a thick infill and summit cone within the Monte Amarelo collapse scar together with partial covering of the outer flanks of the Monte Amarelo volcano with a veneer of younger lavas and scoria cones. The erupted rocks are compositionally varied (ankaramitic nephelinites, basanites, tephrites) and often highly porphyritic. Petrographic criteria were therefore used to aid field mapping, define lithostratigraphic units and demonstrate systematic changes in compositions of erupted magmas through time. Some of these changes, particularly eruptions of ankaramitic magmas, coincide with similar sequences of volcano-structural changes that have occurred prior to the Monte Amarelo collapse and again during the Holocene (beginning around 11 000 years before present; Foeken et al, 2009). The flow-by-flow mapping approach has allowed reconstruction and comparison of the sequences of these structural changes, and thus provides insights into the inferred progressive destabilization of the eastern flank of Fogo during the Holocene, as well as into wide variations in eruption and resurfacing rates that have occurred on decade to century timescales in more recent times. Foeken, J.P.T., Day, S.J. & Stuart, F.M. (2009) Cosmogenic 3He exposure dating of the Quaternary basalts from Fogo, Cape Verdes: Implications for rift zone and magmatic reorganization. Quaternary Geology 4 (2009) 37 - 49.

Day, S. J.

2011-12-01

59

Late Cryogenian-Ediacaran history of the Arabian-Nubian Shield: A review of depositional, plutonic, structural, and tectonic events in the closing stages of the northern East African Orogen  

NASA Astrophysics Data System (ADS)

During the late Cryogenian-Ediacaran (650-542 Ma), the Arabian-Nubian Shield (ANS) underwent final assembly and accretion to the Saharan Metacraton concurrent with the assembly of eastern and western Gondwana. At the end of the Precambrian it lay at one end of the East African Orogen, with its northern margin (present coordinates) forming a low-relief stable shelf facing an open ocean; to the south the ANS transitioned into the Mozambique Belt. The geologic history of the ANS during this period provides insight into the closing developmental stages of one of the world's largest accretionary orogens. Following a 680-640 Ma orogenic event reflecting amalgamation of a core grouping of island-arc terranes (the proto-Arabian-Nubian Shield; pANS), the region underwent extensive exhumation, erosion, and subsidence. Depositional basins formed in the northern and eastern pANS, with those in the east below sea level and connected to an ocean. Periodic basin closure and formation of new basins in other parts of the ANS followed. Many basins were filled by terrestrial, molasse-type sediments interfingering with subordinate to predominant amounts of volcanic rocks. Magmatism was extensive throughout the period, initially characterized by tonalite-trondhjemite-granodiorite (TTG) and granite (monzogranite, syenogranite), but also characterized, from ˜610 Ma on, by increasing amounts of alkali-feldspar granite and alkali granite. The plutons are largely undeformed, except where cut by brittle-ductile shear zones. The magma sources of the late Cryogenian-Ediacaran granitoids were dominated by juvenile crust and(or) depleted mantle and magmas mostly originated in anorogenic, post-collisional, commonly extensional, settings. They were derived by melting and fractionation of anhydrous high-grade metamorphosed lower crust, mafic- to intermediate calc-alkaline crust, and(or) subduction-modified mantle wedges associated with slab break-off or delamination. By ˜630 Ma, the region was affected by oblique (transpressional) convergence of continental blocks that formed eastern and western Gondwana—the pANS was approaching the Saharan Metacraton; north-trending shear and shortening zones developed in the southern ANS; and northwest-trending strike-slip shear zones of the Najd fault system dominated farther north. In the northwestern ANS, convergence and Najd transpression buckled the crust causing structural highs with domes of gneissic infracrust overlain by supracrust composed of ophiolitic and volcanosedimentary assemblages dating from the Tonian-middle Cryogenian period of island-arc activity. The supracrust was extensively translated to the northwest above a high-strain zone. Extension and tectonic escape augmented exhumation of the gneissic infracrust particularly between ˜620-580 Ma. In the northeastern ANS, linear belts of gneiss formed from reworked older intrusive bodies or syntectonic intrusions that were emplaced along Najd faults. By ˜620 Ma a marine basin on the eastern margin of the pANS (present coordinates) was beginning to close. A thick sedimentary assemblage (Abt formation) in this basin underwent metamorphism and folding, and subduction-related magmatism and volcanism farther into this basin (Al Amar arc; >690-615 Ma) was coming to an end. Amalgamation of the Abt formation, Al Amar arc, and the pANS occurred between ˜620 and ˜605 Ma, and terminal collision between the pANS and the Saharan Metacraton was complete by ˜580 Ma. At this time, the ANS was fully assembled. Granite magmatism continued until ˜565-560 Ma and orogeny ceased by ˜550 Ma. During these terminal events, the region underwent strong chemical weathering and became a vast low-relief surface on which Lower Paleozoic sandstone was eventually deposited.

Johnson, P. R.; Andresen, A.; Collins, A. S.; Fowler, A. R.; Fritz, H.; Ghebreab, W.; Kusky, T.; Stern, R. J.

2011-10-01

60

Topographic Evidence for Shield Volcanism on Io  

NASA Technical Reports Server (NTRS)

A volcano was identified whose morphology, especially topography, supports and extends current evidence that shield volcanoes occur on Io. The feature is centered at 30 deg. S, 246 deg w and lies in a region near the terminator. The presence of shield volcanism on Io was inferred from the planimetric configuration of flaws on such features as Ra Patera. A central edifice roughly 40 to 50 km in diameter is situated on intervent plains material, and a broad, slightly elliptical base 75 to 90 km across. The size of this feature is comparable to large shield volcanoes found on Earth. In addition, the topography is similar to some terrestrial shield volcanoes that exhibit a change in slope; the steepening may be explained by shorter and/or thicker flows emplaced during late stage eruptions.

Albin, E. F.; Moore, J. M.; Greeley, R.

1985-01-01

61

Comparison of DOE-2.1E with Energyplus and TRNSYS for Ground Coupled Residential Buildings in Hot anf Humid Climates Stage 1  

E-print Network

dimensional calculations of Slab are integrated with one-dimensional heat conduction calculations of EnergyPlus through iteration. According to Bahnfleth [6], ground surface condition is the most significant boundary condition for the floor heat transfer...ESL-TR-11-12-08 COMPARISON OF DOE-2.1E WITH ENERGYPLUS AND TRNSYS FOR GROUND COUPLED RESIDENTIAL BUILDINGS IN HOT AND HUMID CLIMATES STAGE 1 “Literature Survey on Slab-on-grade Heat Transfer Models of DOE-2, EnergyPlus and TRNSYS...

Andolsun, S.; Culp, C.

2011-01-01

62

Shielding calculations at dismantled synchrocyclotron  

SciTech Connect

The Space Radiation Effects Laboratory located in Newport News, Virginia, was operated by the College of William and Mary for the National Aeronautics and Space Administration. A synchrocyclotron which was formerly in operation in this building was removed in 1980. At several locations, the scattered radiation caused an induced radioactivity within the walls of the cyclotron room. A radiological survey has been performed to determine the amount of residual radioactivity on the walls. Calculations were performed to determine the thickness of the concrete walls and floor for shielding the residual radiation in the cyclotron room. Recommendations are made to minimize exposures from the residual radioactivity on the walls and floor of the cyclotron room to potential occupants working in the building. 19 refs., 1 fig., 2 tabs.

Yalcintas, M.G.

1987-01-01

63

RADIATION SHIELDING MATERIALS  

Microsoft Academic Search

A shielding material is described which has a high shielding ; effectiveness per unit volume and a high capacity for absorbing radiations. The ; material comprises a chemical complex of trivalent cobalt or chromium, such as ; the perrhenates and hexamino trihalides, in combination with a structural ; material such as iron, stainless steel, etc. The complex may be melted

Borst

1962-01-01

64

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

65

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

66

Building fast well-balanced two-stage numerical schemes for a model of two-phase flows  

NASA Astrophysics Data System (ADS)

We present a set of well-balanced two-stage schemes for an isentropic model of two-phase flows arisen from the modeling of deflagration-to-detonation transition in granular materials. The first stage is to absorb the source term in nonconservative form into equilibria. Then in the second stage, these equilibria will be composed into a numerical flux formed by using a convex combination of the numerical flux of a stable Lax-Friedrichs-type scheme and the one of a higher-order Richtmyer-type scheme. Numerical schemes constructed in such a way are expected to get the interesting property: they are fast and stable. Tests show that the method works out until the parameter takes on the value CFL, and so any value of the parameter between zero and this value is expected to work as well. All the schemes in this family are shown to capture stationary waves and preserves the positivity of the volume fractions. The special values of the parameter 0,1/2,1/(1+CFL), and CFL in this family define the Lax-Friedrichs-type, FAST1, FAST2, and FAST3 schemes, respectively. These schemes are shown to give a desirable accuracy. The errors and the CPU time of these schemes and the Roe-type scheme are calculated and compared. The constructed schemes are shown to be well-balanced and faster than the Roe-type scheme.

Thanh, Mai Duc

2014-06-01

67

Heat Shield in Pieces  

NASA Technical Reports Server (NTRS)

This image from NASA's Mars Exploration Rover Opportunity shows the remains of the rover's heat shield, broken into two key pieces, the main piece on the left side and a broken-off flank piece near the middle of the image. The heat shield impact site is identified by the circle of red dust on the right side of the picture. In this view, Opportunity is approximately 20 meters (66 feet) away from the heat shield, which protected it while hurtling through the martian atmosphere.

In the far left of the image, a meteorite called 'Heat Shield Rock,' sits nearby, The Sun is reflecting off the silver-colored underside of the internal thermal blankets of the heat shield.

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 an approximately true-color rendering of the scene acquired around 1:22 p.m. local solar time on Opportunity sol 324 (Dec. 21, 2004) in an image mosaic using panoramic filters at wavelengths of 750, 530, and 430 nanometers.

2005-01-01

68

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

69

Evolution of Hawaiian shield volcano revealed by antecryst-hosted melt inclusions  

NASA Astrophysics Data System (ADS)

Ocean island basalts, exemplified by the Hawaiian Volcanics, are often considered to be the best targets for understanding the chemical and thermal structure of upwelling mantle plumes. The important feature with regards to the petrogenesis of the recent Hawaiian shield building lavas is the existence of a double volcanic loci (Loa and Kea), which has resulted in large-scale heterogeneity between the north-western and south-eastern sides of the plume. The temporal Sr-Nd-Hf-Pb isotopic trends displayed by the Loa-type lavas may have been caused by systematic vertical heterogeneity of the SW part of the Hawaiian plume. The majority of the available OIB samples are limited to the youngest lava flows covering the shield, with the exception of samples obtained from drilled cores and land slide deposits. Thus, sampling is biased to the latest stages of the shield building process, and consequently, so are geochemical studies. We found that the majority of olivine crystals coarser than ˜1 mm in the Hawaiian lavas are antecryst, which originally crystallized from previous stages of Hawaiian magmatism. These anatecrysts were then plastically deformed prior to entrainment in the erupted host magmas. The Pb isotopic compositions of antecryst-hosted melt inclusions reveal that the mantle source components that formed Hawaiian shields successively changed during shield formation. The temporal geochemical trend in the Kilauea melt inclusion could be caused by increasing the degree of partial melting by moving the melting source of the volcano from the periphery to the centre of the plume. The Pb isotopic trend of Koolau melt inclusions are consistent with the previously identified temporal isotopic trend, which shows that the 207Pb/206Pb and 208Pb/206Pb of the Koolau magma systematically increased with time. Thus, antecryst-hosted melt inclusions preserve geochemical information regarding the petrogenesis of the Hawaiian shield lavas, which is unobtainable via whole rock geochemical studies. These observations also demonstrate that a significant fraction of olivine antecrysts are derived from dunite or harzburgite channels/cumulates that were formed by dissolution and/or crystallization processes during previous magmatic events. Thus, the entrainment of inherited mantle-derived crystallization products by younger batches of magma is a common phenomenon in the Hawaiian magma plumbing system.

Tanaka, R.; Sakyi, P. A.; Kobayashi, K.; Nakamura, E.

2009-12-01

70

What Is Radiation Shielding?  

NASA Video Gallery

Kerry Lee, NASA Orion radiation system manager, explains how radiation shielding is used to block harmful particles coming into the spacecraft without producing secondary particles that can cause e...

71

EBT-P gamma-ray-shielding analysis  

SciTech Connect

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 the performance and cost is discussed. Next, 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 load per coil from the gamma-ray sources. Also, a detailed biological-dose survey was performed which included: (a) the dose equivalent inside and outside the building, (b) the dose equivalent from the two mazes of the building, and (c) the skyshine contribution to the dose equivalent.

Gohar, Y.

1983-01-01

72

Shielded cells transfer automation  

SciTech Connect

Nuclear waste from shielded cells is removed, packaged, and transferred manually in many nuclear facilities. Radiation exposure is absorbed by operators during these operations and limited only through procedural controls. Technological advances in automation using robotics have allowed a production waste removal operation to be automated to reduce radiation exposure. The robotic system bags waste containers out of glove box and transfers them to a shielded container. Operators control the system outside the system work area via television cameras. 9 figures.

Fisher, J J

1984-01-01

73

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

74

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

75

Shielded, Automated Umbilical Mechanism  

NASA Technical Reports Server (NTRS)

Umbilical mechanism automatically connects and disconnects various fluid couplings and/or electrical contacts while shielding mating parts from debris. Reacts mating and demating loads internally, without additional supporting structures. All functions - extension of plug, mating, and movement of debris shields - actuated by single motor. If mechanism jams or fails at any point in sequence, override feature in drive train allows manual operation. Designed for service in outer space, where its shields protect against micrometeoroids, debris, ultraviolet radiation, and atomic oxygen. Used on Earth to connect or disconnect fluid or electrical utilities in harsh environments like those of nuclear powerplants or undersea construction sites, or in presence of radioactive, chemical, or biological hazards, for example.

Barron, Daniel R.; Morrill, Brion F.; Jasulaitis, Vytas

1995-01-01

76

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

77

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

78

EBT-P gamma-ray shielding system  

SciTech Connect

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 gamma ray sources. Also, a detailed biological dose survey was performed which included: (a) the dose equivalent inside and outside the building, (b) the dose equivalent from the two mazes of the machine room, and (c) the skyshine contribution to the dose equivalent.

Gohar, Y.

1981-12-01

79

Experimental shielding evaluation of the radiation protection provided by the structurally significant components of residential structures.  

PubMed

The human health and environmental effects following a postulated accidental release of radioactive material to the environment have been a public and regulatory concern since the early development of nuclear technology. These postulated releases have been researched extensively to better understand the potential risks for accident mitigation and emergency planning purposes. The objective of this investigation is to provide an updated technical basis for contemporary building shielding factors for the US housing stock. Building shielding factors quantify the protection from ionising radiation provided by a certain building type. 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 1950s era suburbia and is no longer applicable to the densely populated urban environments realised today. To analyse a building's radiation shielding properties, the ideal approach would be to subject a variety of building types to various radioactive sources and measure the radiation levels in and around the building. While this is not entirely practicable, this research analyses the shielding effectiveness of ten structurally significant US housing-stock models (walls and roofs) important for shielding against ionising radiation. The experimental data are used to benchmark computational models to calculate the shielding effectiveness of various building configurations under investigation from two types of realistic environmental source terms. Various combinations of these ten shielding models can be used to develop full-scale computational housing-unit models for building shielding factor calculations representing 69.6 million housing units (61.3%) in the United States. Results produced in this investigation provide a comparison between theory and experiment behind building shielding factor methodology. PMID:24487195

Dickson, E D; Hamby, D M

2014-03-01

80

Electromagnetic shielding, some simple formulae for closed uniform shields  

Microsoft Academic Search

Electromagnetic shields should be adequate without incurring undue cost or weight. A number of formulas are collected that are consistent with electromagnetic theory. Such formulas will in many cases give shielding estimates quite different from what would be obtained from the use of engineering formulas as presented in widespread handbooks and shielding manuals. The classical, but often distorted, quasistatic formulas

E. Dahlberg

1975-01-01

81

SSC environmental radiation shielding  

Microsoft Academic Search

The environmental radiation shielding requirements of the SSC have been evaluated using currently available computational tools that incorporate the well known processes of energy loss and degradation of high energy particles into Monte Carlo computer codes. These tools permit determination of isodose contours in the matter surrounding a source point and therefore the specification of minimum thicknesses or extents of

1987-01-01

82

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

83

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 W.

84

Flexible Multi-Shock Shield  

NASA Technical Reports Server (NTRS)

Flexible multi-shock shield system and method are disclosed for defending against hypervelocity particles. The flexible multi-shock shield system and method may include a number of flexible bumpers or shield layers spaced apart by one or more resilient support layers, all of which may be encapsulated in a protective cover. Fasteners associated with the protective cover allow the flexible multi-shock shield to be secured to the surface of a structure to be protected.

Christiansen, Eric L. (Inventor); Crews, Jeanne L. (Inventor)

2005-01-01

85

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

86

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

87

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

88

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

89

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

90

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

91

Shielding calculations for SSC  

SciTech Connect

Monte Carlo calculations of hadron and muon shielding for SSC are reviewed with emphasis on their application to radiation safety and environmental protection. Models and algorithms for simulation of hadronic and electromagnetic showers, and for production and transport of muons in the TeV regime are briefly discussed. Capabilities and limitations of these calculations are described and illustrated with a few examples. 12 refs., 3 figs.

Van Ginneken, A.

1990-03-01

92

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

93

Modified shielding jet model for twin-jet shielding analysis  

NASA Technical Reports Server (NTRS)

An analytical model to estimate the shielding of noise emitted from a point noise source has been developed assuming the shielding jet to be a cylinder of constant radius with uniform flow across the cross section. Comparison to experiment indicated that the model overestimates diffraction of sound around the jet in the far downstream region. The shielding jet model is modified to include widening downstream of the nozzle exit. This not only represents a more realistic model of the jet, but is also expected to improve the shielding estimate downstream. The modified jet model incorporates a Mach number dependent widening rate, a corresponding decrease in flow velocity downstream and an equivalent slug flow evaluation to retain the locally parallel flow approximation of the model development. The shielding analysis with modified jet model is compared to measured data for a subsonic isothermal air jet and a simulated hot subsonic jet. Improvement of the shielding estimate is discussed.

Gerhold, C. H.; Gilbride, J.

1983-01-01

94

Effects of shields on cables  

NASA Technical Reports Server (NTRS)

Aircraft wiring subjected to rapidly changing electromagnetic fields was considered. The ways in which shielded cables reduce surge voltages were studied along with the ways in which common practice regarding the use of shields may be at variance with the use required for the control of lightning effects. Courses in which this apparent conflict of use may be resolved were suggested. Noise currents flowing on shields of cables related to the noise signals coupled onto signal conductors were also investigated.

1977-01-01

95

EXAMPLES OF RADIATION SHIELDING MODELS  

SciTech Connect

The attached pictures are examples of shielding models used by WSMS. The models were used in shielding evaluations for Tank 50 pump replacement. They show the relative location of shielding to radiation sources for pumps and pipes. None of the calculations that were associated with these models involved UCNI. The last page contains two pictures from a shielding calculation for the saltstone area. The upper picture is a conceptual drawing. The lower picture is an image copied from the website of a supplier for the project.

Willison, J

2006-07-27

96

Radiation shielding study for superconducting RF cavity test facility at Fermilab  

SciTech Connect

The results of Monte Carlo radiation shielding study performed with the MARS15 code for the vertical test cryostat facility to be installed in the Industrial Building 1 at Fermilab are presented and discussed.

Rakhno, I.; /Fermilab

2006-04-01

97

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

98

PBF Cubicle 13. Shield wall details illustrate shielding technique of ...  

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

PBF Cubicle 13. Shield wall details illustrate shielding technique of stepped penetrations and brick layout scheme for valve stem extension sleeve. Aerojet Nuclear Company. Date: May 1976. INEEL index no. 761-0620-00-400-195280 - Idaho National Engineering Laboratory, SPERT-I & Power Burst Facility Area, Scoville, Butte County, ID

99

Shield Defense of a Larval Tortoise Beetle  

Microsoft Academic Search

Larvae of the folivorous tortoise beetle, Plagiometriona clavata, carry shields formed from feces and exuviae above their bodies. We used an ecologically relevant predatory ant, Formica subsericea, in a bioassay to determine if shields functioned as simple barriers, as previous studies indicated, or whether they were chemical defenses. Shields were necessary for larval survival; shield removal rendered larvae vulnerable. Shields

Fredric V. Vencl; Timothy C. Morton; Ralph O. Mumma; Jack C. Schultz

1999-01-01

100

Two-leg longwall shield mechanics  

Microsoft Academic Search

This report investigates shield mechanics by describing the elastic response and interaction of shield components to applied vertical and horizontal displacements for various canopy and base contact configurations. This research provides information on generalized shield mechanics, which is applicable in describing the behavior of all two-leg shield supports. Utilizing mechanics of materials concepts and known kinematic relationships for two-leg shield

T. M. Barczak; D. E. Schwemmer

1989-01-01

101

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

E-print Network

mostly connects existing mechanical electrical conductive #12; Atlas SCT/Pixel Grounding and Shielding 2 will form electric shields. More Barrel Shield Parts Barrel outer heat shield: Aluminum 150 µm thick fabricated aluminum to simplify electrical contact cooling tubes with

California at Santa Cruz, University of

102

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

103

Topographic evidence for shield volcanism on Io  

NASA Technical Reports Server (NTRS)

Similarities between terrestrial shield volcanoes and a volcano on Io observed in Voyager I imagery of the satellite at 30 deg S, 246 deg 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.

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

1986-01-01

104

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

105

Reflective Shields for Artificial Satellites  

NASA Technical Reports Server (NTRS)

Report proposes reflective shield that protects spacecraft from radiant energy. Also gives some protection against particle beams and cosmic rays. Conceptual shield essentially advanced version of decorative multifaceted mirror balls often hung over dance floors. Mirror facets disperse radiant energy in many directions.

Bouquet, F. L.

1986-01-01

106

Chemistry of Ozone Shield Destruction  

Microsoft Academic Search

A layer of ozone in the atmosphere, called the ozone shield, protects the earth ultraviolet rays. Over the years the ozone shield has been destroyed, and a hole has appeared that allows UVB rays to harm living organisms. The main 'ozone depleting substances', chlorofluorocarbon, is of anthropogenic origin. The chemistry involved is unusual - occurs only if a polar vortex

David Tin Win; Thandee Kywe

107

Radiation Shielding for Fusion Reactors  

SciTech Connect

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

Santoro, R.T.

1999-10-01

108

Shield clothing for DC live working  

Microsoft Academic Search

This paper presents the difference between DC shield clothing and AC shield clothing for live line work. Tests for ion flow and DC electric field are introduced. The essential requirements of DC shield clothing and the test results are discussed

Chen Jiansheng; Zhu Tongchun; Zhang Junlan; Zhang Lihua

1993-01-01

109

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

110

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

111

Estimation of perforation thickness for concrete shield against high-speed impact  

Microsoft Academic Search

We extended the existing engineering two-stage models for high-speed penetration of projectiles into concrete shields and suggested a semi-empirical model that is applicable for truncated bodies of revolution penetrating into shields having a finite thickness. In this model at the first stage of penetration (cratering), the resistance force is a linear function of the distance between the nose of the

G. Ben-Dor; A. Dubinsky; T. Elperin

2010-01-01

112

REACTOR SERVICE BUILDING, TRA635. CAMERA FACING NORTHWEST. BUILDING PROJECTS FROM ...  

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

REACTOR SERVICE BUILDING, TRA-635. CAMERA FACING NORTHWEST. BUILDING PROJECTS FROM AND CONNECTS TO SOUTH WALL OF MTR BUILDING. EARTH BERM SHIELDING PLUG STORAGE BUILDING IS AT RIGHT OF VIEW. INL NEGATIVE NO. 9913. Unknown Photographer, 2/23/1954 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

113

Radiation Shielding Properties of Some Marbles in Turkey  

NASA Astrophysics Data System (ADS)

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 hazordous effect of radition 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.

Güno?lu, K.; Akkurt, I.

2011-12-01

114

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

115

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

116

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

117

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

118

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

119

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

120

Numerical Approach for Computation of Electromagnetic Shielding  

NASA Astrophysics Data System (ADS)

Disturbing magnetic field (so-called magnetic smog) can be in certain areas suppressed by shielding jacket. Disturbing field is possible to be "lead away" from the shielded area with the use of jacket made of materials with high magnetic permeability (so-called passive shielding, or flux-entrapment shielding). If the disturbing field is time-variable, eddy currents are induced into electrically conductive jacket. Magnetic field generated by these eddy currents suppress the disturbing field (this is called active shielding, or lossy magnetic shielding). Both of these principles can be applied altogether (this is called combined shielding). Presented paper states numerical approach to shielding jacket design and is an introduction to following solution of a real problem of magnetic shielding when the disturbing magnetic field is space-time complicated. Effective design of the magnetic shielding should then be formulated as an optimization task.

Mayer, Daniel; Ulrych, Bohuš

2013-06-01

121

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

122

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

123

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

124

Cancer Staging  

MedlinePLUS

... is called metastasis. 2. What are the common elements of staging systems? Staging systems for cancer have ... others focus on a particular type. The common elements considered in most staging systems are as follows: ...

125

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

126

Neutron beamline shielding calculations at the SNS  

NASA Astrophysics Data System (ADS)

A world-class accelerator driven short pulsed neutron source is in the final stages of construction at the Oak Ridge National Laboratory. A 1.4 MW proton beam at 1 GeV energy directed on a mercury target will free neutrons through spallation reactions that will be moderated to thermal and subthermal energies and serve neutron scattering instruments at up to 24 beamlines. At spallation neutron sources, the neutron beams are contaminated by a large fraction of fast neutrons with energies up to the energy of the proton beam incident on the mercury target. Results of design calculations for the Cold Neutron Chopper Spectrometer are presented as an example to demonstrate the neutronics design analyses that are being performed to optimize the lateral beamline shielding as well as the sample and detector area with regard to guaranteeing personal safety, minimizing neutron background and cost.

Gallmeier, Franz X.; Ferguson, Phillip D.; Iverson, Erik B.; Popova, Irina I.; Lu, Wei

2006-06-01

127

New K-Ar ages for calculating end-of-shield extrusion rates at West Maui volcano, Hawaiian island chain  

USGS Publications Warehouse

Thirty-seven new K-Ar ages from West Maui volcano, Hawai'i, are used to define the waning stages of shield growth and a brief episode of postshield volcanism. All but two samples from shield-stage strata have reversed polarity magnetization, so conceivably the exposed shield is not much older than the Olduvai Normal-Polarity subchron, or about 1.8 Ma. The oldest ages obtained are in the range 1.9-2.1 Ma but have large analytical error. Shield volcanism ended about 1.35 Ma, and postshield volcanism followed soon thereafter, persisting until about 1.2 Ma. Exposed shield-stage strata were emplaced at a rate of about 0.001 km3 per year, a rate smaller than historic Hawaiian magmatic rates by a factor of 100. Stratigraphic accumulation rates are similar to those measured previously at Wai'anae volcano (O'ahu) or the upper part of the Mauna Kea shield sequence (Hilo drill core, Hawai'i). These rates diminish sharply during the final 0.3-0.5 m.y. of the shield stage. Hawaiian shield volcanoes begin waning well before their last 0.5 m.y. of life, then end quickly, geologically speaking, if West Maui is representative. ?? Springer-Verlag 2006.

Sherrod, D. R.; Murai, T.; Tagami, T.

2007-01-01

128

Target station shielding issues at the spallation neutron source.  

PubMed

Recent spallation neutron source shielding activities in support of the neutron beam shutters and the hot cell walls are presented. Existing neutron beam shutters can be replaced with concrete at low power or with concrete and steel at approximately 500 kW of beam power. Potential voids in the hot cell walls are analysed to determine the impact on dose rates as a function of void size. A change in the type of shielding work is noted as the project moved from the early design stages as a 'green field' site to the current stage as a construction project nearing completion, where issues to be addressed are approaching retrofit-type analyses. PMID:16381707

Ferguson, P D; Gallmeier, F X; Iverson, E B; Popova, I I

2005-01-01

129

Shielding vacuum fluctuations with graphene  

E-print Network

The Casimir-Polder interaction of ground-state and excited atoms with graphene is investigated with the aim to establish whether graphene systems can be used as a shield for vacuum fluctuations of an underlying substrate. We calculate the zero-temperature Casimir-Polder potential from the reflection coefficients of graphene within the framework of the Dirac model. For both doped and undoped graphene we show limits at which graphene could be used effectively as a shield. Additional results are given for AB-stacked bilayer graphene.

Sofia Ribeiro; Stefan Scheel

2013-10-22

130

Stress fields associated with the growth of a large shield volcano (La Palma, Canary Islands)  

Microsoft Academic Search

Measurements of dyke orientations and fault slip data have been taken in 39 stations located in the northern part of the island of La Palma (Canary Archipelago). These structures affect the materials belonging to the submarine growth stage and to the lower units of the subaerial shield volcano stage. Four sets of dykes have been distinguished (Groups I, II, III-1,

Carlos Fernández; Julio de la Nuez; Ramón Casillas; Encarnación García Navarro

2002-01-01

131

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

132

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

133

Shielding effectiveness of conductive polymers  

Microsoft Academic Search

The plane wave shielding effectiveness of two new materials, conductive polymers polyacetylene and PBT doped by ion implantation with iodine, is evaluated as a function of frequency, electrical thickness, doping, polarization, and angle of incidence. Conductivity of the polymers, measured in previous investigations by the cavity perturbation technique, is used to compute the overall reflection and transmission coefficients of single

Krishna Naishadham

1992-01-01

134

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

135

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

136

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

137

Thermal Degradation of Lead Monoxide Filled Polymer Composite Radiation Shields  

SciTech Connect

Lead monoxide filled Isophthalate resin particulate polymer composites were prepared with different filler concentrations and investigated for physical, thermal, mechanical and gamma radiation shielding characteristics. This paper discusses about the thermo gravimetric analysis of the composites done to understand their thermal properties especially the effect of filler concentration on the thermal stability and degradation rate of composites. Pristine polymer exhibits single stage degradation whereas filled composites exhibit two stage degradation processes. Further, the IDT values as well as degradation rates decrease with the increased filler content in the composite.

Harish, V. [Department of Physics, Government First Grade College, Shivamogga-577201 (India); Nagaiah, N. [Department of Physics, Bangalore University, Jnanabharati, Bangalore-560056 (India)

2011-07-15

138

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

139

Shielding and grounding in large detectors  

SciTech Connect

Prevention of electromagnetic interference (EMI), or ``noise pickup,`` is an important design aspect in large detectors in accelerator environments. Shielding effectiveness as a function of shield thickness and conductivity vs the type and frequency of the interference field is described. Noise induced in transmission lines by ground loop driven currents in the shield is evaluated and the importance of low shield resistance is emphasized. Some measures for prevention of ground loops and isolation of detector-readout systems are discussed.

Radeka, V.

1998-09-01

140

High-explosives press safety shield testing  

Microsoft Academic Search

The DOE Explosives Safety Manual requires shrapnel containment testing of high explosives pressing safety shields when pressing operations present the hazard of metal fragmentation. Los Alamos National Laboratory Group M-7 tested the three types of press shields now in use. Operator protection was demonstrated in all horizontal directions. However, minor modifications are needed on two shield styles to contain some

1990-01-01

141

Shield timbering frame for timbering mines  

Microsoft Academic Search

A shield timbering frame for timbering mines adjacent a mining face, comprises a horizontal floor-engaging skid and a breaking shield extending obliquely over the skid which is connected to the skid by a pair of longitudinally spaced, lemniscate guide rods. A roof cap member has an inner end which is pivoted to the upper end of the breaking shield and

M. Koppers; L. Pawelski

1980-01-01

142

Flexible Protective Shield For Newly Welded Joints  

NASA Technical Reports Server (NTRS)

Simple device promotes defect-free welds in oxidation-prone metals. Welding torch pulls trailing shield behind to provide protective shield of argon gas over hot weld bead. Guide at front of torch holder feeds welding wire to joint. Shield bent or straightened to fit closely against weld joint.

Dyer, Gerald E.

1988-01-01

143

S3G PROJECT, SHIELD TEST INSTRUMENTATION  

Microsoft Academic Search

A description of the instrumentation used in shield tests on the S3O ; plant is presented. The tests were performed to evaluate the shield in relation ; to the specifications and included measurement of fast neutron and gamma doses ; emerging from the shield and epithermal and thermal neutron fluxes. Each ; measuring system is considered along with methods of

D. W. Johnson; R. J. Mazairz; E. J. Romesberg

1959-01-01

144

Theoretical and numerical aspects concerning magnetostatic shielding  

Microsoft Academic Search

This paper deals with the analytical and numerical evaluation of the shielding efficiency for the magneto static shields. The paper has a teaching purpose. The attenuation for spherical and cylindrical one layer shields was considered. Also the influence of the materials was investigated (non- saturable, saturable and superconductive). Analytical and numerical values were computed and compared and a good agreement

Dumitru Cazacu; Emilian Lefter

2011-01-01

145

Stellar activity and magnetic shielding  

E-print Network

Stellar activity has a particularly strong influence on planets at small orbital distances, such as close-in exoplanets. For such planets, we present two extreme cases of stellar variability, namely stellar coronal mass ejections and stellar wind, which both result in the planetary environment being variable on a timescale of billions of years. For both cases, direct interaction of the streaming plasma with the planetary atmosphere would entail servere consequences. In certain cases, however, the planetary atmosphere can be effectively shielded by a strong planetary magnetic field. The efficiency of this shielding is determined by the planetary magnetic dipole moment, which is difficult to constrain by either models or observations. We present different factors which influence the strength of the planetary magnetic dipole moment. Implications are discussed, including nonthermal atmospheric loss, atmospheric biomarkers, and planetary habitability.

Grießmeier, J -M; Lammer, H; Grenfell, J L; Stadelmann, A; Motschmann, U; 10.1017/S1743921309992961

2010-01-01

146

Deployment of 'Parasol' solar shield  

NASA Technical Reports Server (NTRS)

The deployment of the 'Parasol' solar shield, a sunshade to help cool the overheated Orbital Workshop of the Skylab 1 space station cluster in Earth orbit, can be seen in the reproduction taken from a color television transmission made by a TV camera aboard the space station. The camera is in the Command Module; and the view is looking through the truss of the Apollo Telescope Mount. The sunshade is only partially deployed in this picture.

1973-01-01

147

Shielding studies at Mound Laboratory  

Microsoft Academic Search

Neutron shielding is done to protect workers from excessive radiation and to keep a low neutron background for research in neutron counting. To meet health standards the total neutron flux allowable is 150 n\\/cm\\/sec per eight hours, or 50 n\\/cm\\/sec per twenty-four hours. Literature values for the absorption coefficients of paraffin and water are considered, and some experimental data is

J. E. Bradley; J. L. Richmond

1948-01-01

148

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

149

Space vehicle meteoroid shielding design  

NASA Technical Reports Server (NTRS)

Design principles of spaced, multiwall meteoroid protection are investigated in the light of experimental data generated during the Apollo Program. The outer wall or shield is shown to be the most important element in the meteoroid-spacecraft interaction. The condition of the debris is primarily a function of the shock pressure, the melting points of the meteoroid and the shield, and the length of the meteoroid and thickness of the shield. Spacing between the walls is effective up to approximately 100 times the length of the meteoroid. The required thickness of the second wall is shown to be proportional to the meteoroid mass, velocity, and density, and to the spacing between the walls, taken with exponents dependent upon the condition of the debris. The effects of placing additional elements (insulation or honeycomb cells) between the two walls are discussed, and the efficiency of various protective configurations is presented. An analysis of the meteoroid protection proposed for the Comet Halley probe is included as an appendix.

Cour-Palais, B. G.

1979-01-01

150

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

151

Heat-shield design for glovebox applications.  

SciTech Connect

Heat shields can often be used in place of insulation materials as an effective means of insulating glovebox furnace vessels. If used properly, shields can accomplish two important objectives: thermal insulation of the vessel to maintain a desired process temperature and protection of the glovebox, equipment, and user. A heat-shield assembly can be described as an arrangement of thin, properly-spaced, metal sheets that reduce radiation heat transfer. The main problem encountered in the design of a heat shield assembly is choosing the number of shields. In determining the heat transfer characteristics of a heat-shield assembly, a number of factors must be taken into consideration. The glovebox or outside environment, material properties, geometry, and operating temperature all have varying effects on the expected results. A simple method, for planar-horizontal and cylindrical-vertical shields, allowing the approximation of the outermost shield temperature, the practical number of shields, and the net heat-transfer rate will be presented. Methods used in the fabrication of heat-shield assemblies will also be discussed.

Frigo, A. A.

1998-07-10

152

Miniature, shielded electrical connector with strain relief  

NASA Technical Reports Server (NTRS)

An electrical connector assembly includes a wire bundle having at least one wire with a metal shield surrounding at least a portion of the wire. The shield has an end portion and provides electromagnetic interference protection to the wire. A backshell includes a body and a cover secured to the body together defining an internal cavity with the wire at least partially arranged within the cavity. The backshell provides EMI protection for the portion of the wire bundle not covered by the shield. The backshell includes a hole in a wall of either the body or the cover with the end portion of the shield extending through the hole. The clamp is secured about the body and the cover with the end portion of the shield arranged between the clamp and the backshell grounding the shield to the backshell. The clamp forces the backshell into engagement with the wire bundle to provide strain relief for the wire bundle.

Diep, Chuong H. (Inventor)

2006-01-01

153

Optimation of cooled shields in insulations  

NASA Astrophysics Data System (ADS)

A method to optimize the location, temperature, and heat dissipation rate of each cooled shield inside an insulation layer was developed. The method is based on the minimization of the entropy production rate which is proportional to the heat leak across the insulation. It is shown that the maximum number of shields to be used in most practical applications is three. However, cooled shields are useful only at low values of the overall, cold wall to hot wall absolute temperature ratio. The performance of the insulation system is relatively insensitive to deviations from the optimum values of the temperature and location of the cooling shields. Design curves for rapid estimates of the locations and temperatures of cooling shields in various types of insulations, and an equation for calculating the cooling loads for the shields are presented.

Chato, J. C.; Khodadadi, J. M.; Seyed-Yagoobi, J.

1984-04-01

154

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

155

Shielding of a 3600 curie AmBe source  

E-print Network

body, neutron activation analysis irzadiator employing 3600 cuties of AmBe. The proposed shielding material foz 241 construction of the irradiator is a high density concrete. The izzadiatoz vill be located in an already existing building vhich limits... facility. 1n integral pazt of this facility vill be a vhole body, neutron activation analysis irradiator (Benedetto 1988). The irradiator vill be located on the ground level of the hospital and vill be in an area that is to be occupied 24 hours a day...

Grimes, Mary Jeanine

2012-06-07

156

Magnetic shielding for magnetically levitated trains  

Microsoft Academic Search

The magnetically levitated train has on-board superconducting coils for propulsion guide and support which generate mmf of several hundred kAT. The effect of such high magnetic field on the human body, electronics devices, wrists watches, etc., is not well known. The shielding problem in Miyazaki experimental railway with the on-board shielding coils for support is investigated. When no magnetic shielding

S. Okuma; H. Sugiyama; Y. Amemiya

2009-01-01

157

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

158

Continuous Energy, Multi-Dimensional Transport Calculations for Problem Dependent Resonance Self-Shielding  

SciTech Connect

The overall objective of the work here has been to eliminate the approximations used in current resonance treatments by developing continuous energy multi-dimensional transport calculations for problem dependent self-shielding calculations. The work here builds on the existing resonance treatment capabilities in the ORNL SCALE code system.

T. Downar

2009-03-31

159

THE CALCULATION OF THE GAMMA SHIELDING PROTECTION IN EXPANDING RADIATION FIELDS  

Microsoft Academic Search

The usual, purely exponential calculation of shield thicknesses for ; gamma radiators supplies minimum values which in many cases cannot provide the ; desired protection, since the influence of secondary radiation causcd by single ; or multiple Compton processes is not taken into consideration in the exponential ; calculation. By applying the dose build-up factor B, which can be represented

Plesch

1958-01-01

160

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

161

Accelerator magnet designs using superconducting magnetic shields  

SciTech Connect

Superconducting dipoles and quadrupoles for existing accelerators have a coil surrounded by an iron shield. The shield limits the fringe field of the magnet while having minimal effect on the field shape and providing a small enhancement of the field strength. Shields using superconducting materials can be thinner and lighter and will not experience the potential of a large de-centering force. Boundary conditions for these materials, material properties, mechanical force considerations, cryostat considerations and some possible geometrical configurations for superconducting shields will be described. 7 refs., 3 figs., 3 tabs.

Brown, B.C.

1990-10-01

162

THEMIS discovers holes in Earth's solar shield  

NASA Video Gallery

This animation shows the latest findings from the Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission. Earth's magnetic field; which shields our planet from severe ...

163

Fan broadband noise shielding for over-wing engines  

NASA Astrophysics Data System (ADS)

Increasingly demanding community noise targets are promoting noise performance ever higher on the list of airliner design drivers. In response, significant noise reductions are being made, though at a declining rate—it appears that a whole airframe approach is now needed to achieve significant further gains. As a possible step in this direction, over-wing engine installations are considered here, which use the airframe itself as a noise shield. The paper is the account of an experimental investigation of the comparative shielding performances of a range of relative engine positions on such a layout. Using the statistical modelling technique Kriging, we build an approximation of the noise shielding metric as a function of the position of the engines above the wing—this can serve as the input to multi-disciplinary design trade-off studies. We then compare the results found with the results of applying simple half-barrier diffraction theory to the same problem. We conclude that the latter could be considered as a first order, conceptual design tool, though it misses certain features of the design merit landscape identified by the experiment presented here.

Powell, Stephen; Sóbester, András; Joseph, Phillip

2012-11-01

164

Third Stage  

NASA Video Gallery

Once the third stage finishes its work, Kepler will have sufficient energy to leave the gravitational pull of Earth and go into orbit around the Sun, trailing behind Earth and slowly drifting away ...

165

Shielding, Levitation, Propulsion G. W. Jewell, Chariman Method for expanding the uniformly shielded area in a short-length  

E-print Network

Shielding, Levitation, Propulsion G. W. Jewell, Chariman Method for expanding the uniformly shielded area in a short-length open-ended cylindrical magnetic shield K. Oshita, I. Sasada,a) H. Naka shielded area of the axial magnetic field in a relatively short, open-structure axial magnetic shield can

Paperno, Eugene

166

Throughput of shielded twisted-pair cables using wire-shield modes in the presence of radio ingress  

Microsoft Academic Search

This paper investigates the achievable throughput of shielded twisted-pair (STP) copper cables exploiting alternative propagation modes. Treating the shield as joint common, we form wire-shield paths. The shield is expected to substantially reduce the amount of radio ingress entering the cable. Thus, we consider the impact of the shield effectiveness on the throughput limits. Using model and measurements presented in

M. Jakovljevic; T. Magesacher; P. O. Borjesson; M. Sanchez; S. Zazo

2009-01-01

167

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

168

Project Desert Shield-Preschool Style.  

ERIC Educational Resources Information Center

Describes Project Desert Shield, a curriculum that preschool children and teachers at a U.S. military base in Germany developed to embrace and constructively deal with the interests and concerns of the children about Operation Desert Shield/Desert Storm through dramatic play. (Author/BB)

Suskind, Diane

1993-01-01

169

Effects of shielding on railgun inductance gradient  

Microsoft Academic Search

A railgun uses electromagnetic propulsion to launch a projectile. Shielding of a railgun by conductors is one of the best methods for decreasing inner pressure on the rails. The magnetic field which is produced by shield eddy currents neutralizes the forces pressing rails outward and prevents structure deformation. By implementing the FE method on the railgun cross section, we consider

EIham Sharifi Moghaddam; A. Keshtkar; S. M. Nematollah Zadeh

2004-01-01

170

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

171

Prediction of Jet Noise Shielding Dimitri Papamoschou*  

E-print Network

Prediction of Jet Noise Shielding Dimitri Papamoschou* University of California, Irvine, CA 92697, USA This study is motivated by the development of aircraft that use jet noise shielding for diffraction of sound from omnidirectional point sources. However, the jet noise source is distributed

Papamoschou, Dimitri

172

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

173

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

174

GAMMA-RADIOMETRIC INVESTIGATIONS OF REACTOR SHIELDING  

Microsoft Academic Search

The testing of reactor shielding using scintillation counters and gamma-; ray sources has proved a cheaper and less time-consuming method for thick walls ; than radiography with Co⁶° and film. In investigations carried out up to ; now on thick lead shields the average defect has amounted to about 2%. The ; position of the defect is clearly marked on

Somer

1960-01-01

175

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

176

Thermosetting polymer composites for EMI shielding applications  

Microsoft Academic Search

Efforts have been made towards developing lightweight EMI shielding thermosetting composites materials using room temperature curing epoxy novalac cyclo aliphatic amine hardener system. Average Shielding efficiency (SE) values (100 KHz to 1 GHz) of above 50 dB have been obtained for Carbon Fibre Reinforced Polymeric (CFRP) composite laminates, with variants of glass fabric and aluminium mesh included along with. Sandwich

S. Sankaran; S. Dasgupta; K. Ravi Sekhar; M. N. Jagdish Kumar

2006-01-01

177

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

178

Demagnetization of magnetically shielded rooms  

NASA Astrophysics Data System (ADS)

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-Grüneberg, S.; Stollfuß, D.; Burghoff, M.

2007-03-01

179

Radiation Shielding Systems Using Nanotechnology  

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

180

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

181

University Buildings Landmark Buildings  

E-print Network

Pharmacy S Planning, Architecture and Civil Engineering T Politics, International Studies and Philosophy V Centre for Cancer Research and Cell Biology (CCRCB) 20 Chrono 13 Counselling Service 9 Crèches 10 David Bates Building 29 David Keir Building 1n Development and Alumni Relations 13 Disability Services 8 Drama

Paxton, Anthony T.

182

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

183

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

184

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

185

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

186

21 CFR 886.4750 - Ophthalmic eye shield.  

...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

187

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

188

An intrinsically safe facility for forefront research and training on nuclear technologies — ADS shielding  

NASA Astrophysics Data System (ADS)

A detailed study of a very simple Accelerator-Driven System (ADS) shielding concept is carried out by means of the MCNPX Monte Carlo code. The design of a multilayer shielding scheme, together with an underground reactor host room sketch, is shown to be very effective for the exposure levels to ionizing radiations, in the upside experimental building and in the ground all around the reactor host room, being fully negligible. Transient heat is also estimated, founding that no residual radiation leaks out through ADS structures in the host room after shutdown.

Frasciello, O.; Ciotti, M.

2014-04-01

189

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

190

Postshield stage transitional volcanism on Mahukona Volcano, Hawaii  

USGS Publications Warehouse

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 on submarine Mahukona Volcano, Hawaii. These ages are younger than the inferred end of the tholeiitic shield stage and indicate that the volcano had entered the postshield alkalic stage before going extinct. Previously reported elevated helium isotopic ratios of lavas from one of these cones were incorrectly interpreted to indicate eruption during a preshield alkalic stage. Consequently, high helium isotopic ratios are a poor indicator of eruptive stage, as they occur in preshield, shield, and postshield stage lavas. Loihi Seamount and Kilauea are the only known Hawaiian volcanoes where the volume of preshield alkalic stage lavas can be estimated. ?? Springer-Verlag 2008.

Clague, D.A.; Calvert, A.T.

2009-01-01

191

Performance of Whipple Shields at Impact Velocities above 9 km/s  

NASA Technical Reports Server (NTRS)

Whipple shields were first proposed as a means of protecting spacecraft from the impact of micrometeoroids in 1947 [1] and are currently in use as micrometeoroid and orbital debris shields on modern spacecraft. In the intervening years, the function of the thin bumper used to shatter or melt threatening particles has been augmented and enhanced by the use of various types and configurations of intermediate layers of various materials. All shield designs serve to minimize the threat of a spall failure or perforation of the main wall of the spacecraft as a result of the impact of the fragments. With increasing use of Whipple shields, various ballistic limit equations (BLEs) for guiding the design and estimating the performance of shield systems have been developed. Perhaps the best known and most used are the "new" modified Cour-Palais (Christiansen) equations [2]. These equations address the three phases of impact: (1) ballistic (<3 km/s), where the projectile is moving too slowly to fragment and essentially penetrates as an intact projectile; (2) shatter (3 to 7 km/s), where the projectile fragments at impact and forms an expanding cloud of debris fragments; and (3) melt/vaporization (>7 km/s), where the projectile melts or vaporizes at impact. The performance of Whipple shields and the adequacy of the BLEs have been examined for the first two phases using the results of impact tests obtained from two-stage, light-gas gun test firings. Shield performance and the adequacy of the BLEs has not been evaluated in the melt/vaporization phase until now because of the limitations of launchers used to accelerate projectiles with controlled properties to velocities above 7.5 km/s. A three-stage, light-gas gun, developed at the University of Dayton Research Institute (UDRI) [3], is capable of launching small, aluminum spheres to velocities above 9 km/s. This launcher was used to evaluate the ballistic performance of two Whipple shield systems, various thermal protection system materials, and other spacecraft-related materials to the impact of 1.6-mm- to 2.6-mm-diameter, 2017-T4 aluminum spheres at impact velocities ranging from 8.91 km/s to 9.28 km/s. Test results, details of the shield systems, and nominal ballistic limits for the two Whipple shields are shown in Figures 1 and 2.

Christiansen, Eric L.; Davis, Bruce A.; Piekutowski, Andrew J.; Poormon, Kevin L.

2009-01-01

192

Thermal testing of solid neutron shielding materials  

SciTech Connect

Two legal-weight truck casks the GA-4 and GA-9, will carry four PWR and nine BWR spent fuel assemblies, respectively. Each cask has a solid neutron shielding material separating the steel body and the outer steel skin. In the thermal accident specified by NRC regulations in 10CFR Part 71, the cask is subjected to an 800{degree}C environment for 30 minutes. The neutron shield need not perform any shielding function during or after the thermal accident, but its behavior must not compromise the ability of the cask to contain the radioactive contents. In May-June 1989 the first series of full-scale thermal tests was performed on three shielding materials: Bisco Products NS-4-FR, and Reactor Experiments RX-201 and RX-207. The tests are described in Thermal Testing of Solid Neutron Shielding Materials, GA-AL 9897, R. H. Boonstra, General Atomics (1990), and demonstrated the acceptability of these materials in a thermal accident. Subsequent design changes to the cask rendered these materials unattractive in terms of weight or adequate service temperature margin. For the second test series, a material specification was developed for a polypropylene based neutron shield with a softening point of at least 280{degree}F. The neutron shield materials tested were boronated (0.8--4.5%) polymers (polypropylene, HDPE, NS-4). The Envirotech and Bisco materials are not polypropylene, but were tested as potential backup materials in the event that a satisfactory polypropylene could not be found.

Boonstra, R.H.

1992-09-01

193

Thermal testing of solid neutron shielding materials  

SciTech Connect

Two legal-weight truck casks the GA-4 and GA-9, will carry four PWR and nine BWR spent fuel assemblies, respectively. Each cask has a solid neutron shielding material separating the steel body and the outer steel skin. In the thermal accident specified by NRC regulations in 10CFR Part 71, the cask is subjected to an 800[degree]C environment for 30 minutes. The neutron shield need not perform any shielding function during or after the thermal accident, but its behavior must not compromise the ability of the cask to contain the radioactive contents. In May-June 1989 the first series of full-scale thermal tests was performed on three shielding materials: Bisco Products NS-4-FR, and Reactor Experiments RX-201 and RX-207. The tests are described in Thermal Testing of Solid Neutron Shielding Materials, GA-AL 9897, R. H. Boonstra, General Atomics (1990), and demonstrated the acceptability of these materials in a thermal accident. Subsequent design changes to the cask rendered these materials unattractive in terms of weight or adequate service temperature margin. For the second test series, a material specification was developed for a polypropylene based neutron shield with a softening point of at least 280[degree]F. The neutron shield materials tested were boronated (0.8--4.5%) polymers (polypropylene, HDPE, NS-4). The Envirotech and Bisco materials are not polypropylene, but were tested as potential backup materials in the event that a satisfactory polypropylene could not be found.

Boonstra, R.H.

1992-09-01

194

Caisson shield for arctic offshore production platform  

SciTech Connect

A caisson shield for the protection of an offshore production platform and, more particularly, a caisson shield for use in an arctic environment for the protection of the offshore structure in iceberg-infested waters which is capable of absorbing the destructive forces of an impact produced by a large iceberg. The caisson shield consists of an essentially annular concrete structure encircling at least the submerged support section of the offshore production platform including vertically upstanding concentrically spaced, annular side walls, a horizontal slab base resting on the marine bottom on which the side walls are supported, and a slab top supported on the side walls, and including annularly spaced internal radial partition walls whereby the entire overall caisson shield structure provides a generally toroidal configuration incorporating a plurality of closed compartments. In one embodiment of the invention, located along the outer annular wall is a plurality of arcuate wall sections forming a series of arches and enclosed compartments between each arcuate wall section and the outer annular wall, which impart a ''scallop-like'' configuration to the outer circumference of the caisson shield. The ''scallop-like'' outer walls are capable of resisting and absorbing extremely high ice loads by being adapted to progressively crush the leading edge of an impacting iceberg and to thereby minimize the crush of the iceberg against the caisson shield before coming to rest against the shield.

Clinton, J. D.; Reusswig, G. H.

1985-03-12

195

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

196

Seismic Crystals And Earthquake Shield Application  

E-print Network

We theoretically demonstrate that earthquake shield made of seismic crystal can damp down surface waves, which are the most destructive type for constructions. In the paper, seismic crystal is introduced in aspect of band gaps (Stop band) and some design concepts for earthquake and tsunami shielding were discussed in theoretical manner. We observed in our FDTD based 2D elastic wave simulations that proposed earthquake shield could provide about 0.5 reductions in magnitude of surface wave on the Richter scale. This reduction rate in magnitude can considerably reduce destructions in the case of earthquake.

B. Baykant Alagoz; Serkan Alagoz

2009-02-09

197

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

198

Planned Change Request for Shielded Containers  

E-print Network

of Transportation (DOT) 7A Type A and the Nuclear Regulatory Commission (NRC) Type B drop tests and are awaiting regulatory approval. The RH waste that will be emplaced in shielded containers is included in the current

199

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

200

Projectile Density Effects on Shield Performance  

NASA Technical Reports Server (NTRS)

In the past, the orbital debris environment was modeled as consisting entirely of aluminum particles. As a consequence, most of the impact test database on spacecraft micro-meteoroid and orbital debris (MMOD) shields, and the resulting ballistic limit equations used to predict shielding performance, has been based on using aluminum projectiles. Recently, data has been collected from returned spacecraft materials and other sources that indicate higher and lower density components of orbital debris also exist. New orbital debris environment models such as ORDEM2008 provide predictions of the fraction of orbital debris in various density bins (high = 7.9 g/cu cm, medium = 2.8 g/cu cm, and low = 0.9-1.1 g/cu cm). This paper describes impact tests to assess the effects of projectile density on the performance capabilities of typical MMOD shields. Updates to shield ballistic limit equations are provided based on results of tests and analysis.

Christiansen, Eric L.; Lear, Dana; Lyons, Frankel; Davis, Alan

2009-01-01

201

Thermal Shield and Reactor Structure Temperatures  

SciTech Connect

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

Collier, A.R.

2001-07-31

202

Curiosity Bids Goodbye to Heat Shield  

NASA Video Gallery

This video of thumbnail images from the Mars Descent Imager (MARDI) on NASA's Curiosity rover shows the heat shield dropping away from the rover on Aug. 5 PDT (Aug. 6 EDT). It covers the first 25 s...

203

Undulator Beam Pipe Magnetic Shielding Effect Tests  

SciTech Connect

The proposed stainless steel beampipe for the LCLS undulator has a measurable shielding effect on the magnetic field of the LCLS undulators. This note describes the tests used to determine the magnitude of the shielding effect, as well as deviations in the shielding effect caused by placing different phase shims in the undulator gap. The effect of the proposed Steel strongback which will be used to support the beam pipe, was also studied. A hall probe on a 3 axis movement system was set up to measure the main component of the magnetic field in the Prototype Undulator. To account for temperature variations of the magnetic field of the undulator for successive tests, a correction is applied which is described in this technical note. Using this method, we found the shielding effect, the amount which the field inside the gap was reduced due to the placement of the beampipe, to be {approx}10 Gauss. A series of tests was also performed to determine the effect of phase shims and X and Y correction shims on the shielding. The largest effect on shielding was found for the .3 mm phase shims. The effect of the .3 mm phase shims was to increase the shielding effect {approx}4 Gauss. The tolerance for the shielding effect of the phase shims is less than 1 gauss. The effect of the strongback was seen in its permanent magnetic field. It introduced a dipole field across the measured section of the undulator of {approx}3 gauss. This note documents the tests performed to determine these effects, as well as the results of those tests.

Fisher, Andrew; Wolf, Zachary; /SLAC; ,

2010-11-23

204

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

205

Radiation shielding of the main injector  

SciTech Connect

The radiation shielding in the Fermilab Main Injector (FMI) complex has been carried out by adopting a number of prescribed stringent guidelines established by a previous safety analysis. Determination of the required amount of radiation shielding at various locations of the FMI has been done using Monte Carlo computations. A three dimensional ray tracing code as well as a code based upon empirical observations have been employed in certain cases.

Bhat, C.M.; Martin, P.S.

1995-05-01

206

The effect of small variations in the magnetization curves of shielding material upon shielded fields  

NASA Astrophysics Data System (ADS)

The shielding of strong electromagnetic fields at power frequency, performed by ferromagnetic plates, is often successfully modelled by the effective reluctivity. This method delivers good results for the RMSvalue of the shielded field. The following paper shows that a small variation of the magnetization curve (e.g.by taking another material charge) can strongly influence the shielded field. The field calculation is performed by the Finite Element Method (FEM), where for the interior plate region a)finite elements and b)non-linear Impedance Boundary Conditions (IBC) are used which circumvents the need to discretize the shielding plate.

Kost, A.; Jacobs, R. T.; Hahn, A.

2007-08-01

207

Anhysteretic Permeability and Magnetic Shielding Effect of Steel Sheets for Magnetic Shield  

NASA Astrophysics Data System (ADS)

Recently, cathode ray tubes (CRTs) have become flat and larger, and the magnetic shielding against the terrestrial magnetic field is becoming more important for CRTs to improve the image quality. As CRTs of TV sets and computer monitors are used after the degaussing process, it is necessary to consider the magnetic shielding effect in terms of the anhysteretic permeability. In this paper, dependence of anhysteretic permeability on the chemical composition and the microstructure of steel sheets for inner magnetic shields has been studied. In addition, the importance of anhysteretic permeability on magnetic shielding has been experimentally investigated.

Fujita, Koichiro; Matsuoka, Hideki; Hiratani, Tatsuhiko; Tahara, Kenji; Tanaka, Yasushi

208

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

209

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

PubMed

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. PMID:12455499

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

2002-12-01

210

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

211

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.

2005-12-06

212

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.

213

Preliminary shielding estimates for the proposed National ISOL Radioactive Ion Beam (RIB) Facility at Oak Ridge  

SciTech Connect

ORNL built a first-generation Radioactive Ion Beam (RIB) facility for astrophysics and nuclear physics research; it was named Holifield Radioactive Ion Beam Facility (HRIBF) and is based on the Isotope Separator On Line (ISOL) technique. Planning is underway for a second- generation facility, the National ISOL RIB facility at Oak Ridge; it will build on the existing HRIBF and may utilize many existing components and shielded areas. Preliminary upgrade plan for the new facility includes: adding a superconducting booster for the tandem accelerator; replacing the 1960-vintage, 60-MeV proton, 50-microamp ORIC (Oak Ridge Isochronous Cyclotron) with a modern 200-MeV proton, 200-microamp cyclotron; and building a high-power {sup 238}U fission target to accept the 200-MeV proton beam. This report summarizes the results of a preliminary 1-D shielding analysis of the proposed upgrade, to determine the shielding requirements for a 0.25 mrem/h dose rate at the external surface of the exclusion area. Steel shielding weights ranging from 60 to 100 metric tons, were considered manageable; these could be reduced by a factor of 2 to 3 if the orientation of the proposed target station was changed.

Johnson, J.O.; Gabriel, T.A.; Lillie, R.A.

1996-10-01

214

Space Shielding Materials for Prometheus Application  

SciTech Connect

At the time of Prometheus program restructuring, shield material and design screening efforts had progressed to the point where a down-selection from approximately eighty-eight materials to a set of five ''primary'' materials was in process. The primary materials were beryllium (Be), boron carbide (B{sub 4}C), tungsten (W), lithium hydride (LiH), and water (H{sub 2}O). The primary materials were judged to be sufficient to design a Prometheus shield--excluding structural and insulating materials, that had not been studied in detail. The foremost preconceptual shield concepts included: (1) a Be/B{sub 4}C/W/LiH shield; (2) a Be/B{sub 4}C/W shield; (3) and a Be/B{sub 4}C/H{sub 2}O shield. Since the shield design and materials studies were still preliminary, alternative materials (e.g., {sup nal}B or {sup 10}B metal) were still being screened, but at a low level of effort. Two competing low mass neutron shielding materials are included in the primary materials due to significant materials uncertainties in both. For LiH, irradiation-induced swelling was the key issue, whereas for H{sub 2}O, containment corrosion without active chemistry control was key, Although detailed design studies are required to accurately estimate the mass of shields based on either hydrogenous material, both are expected to be similar in mass, and lower mass than virtually any alternative. Unlike Be, W, and B{sub 4}C, which are not expected to have restrictive temperature limits, shield temperature limits and design accommodations are likely to be needed for either LiH or H{sub 2}O. The NRPCT focused efforts on understanding swelting of LiH, and observed, from approximately fifty prior irradiation tests, that either casting ar thorough out-gassing should reduce swelling. A potential contributor to LiH swelling appears to be LiOH contamination due to exposure to humid air, that can be eliminated by careful processing. To better understand LiH irradiation performance and mitigate the risks in LiH development for a project with an aggressive schedule like JIMO, some background or advanced development effort for LiH should be considered for future space reactor projects.

R. Lewis

2006-01-20

215

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

E-print Network

for SCT. This proposal mostly connects existing mechanical and electrical conductive #12;Atlas SCT the shield: the shield provides a conductive path for all the metal connecting to its surface. All conductors. The barrel outer heat shield (150 µm aluminum) is the main element of the shield. #12;Atlas SCT

California at Santa Cruz, University of

216

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

217

University Buildings Landmark Buildings  

E-print Network

and Civil Engineering T Politics, International Studies and Philosophy V Psychology W Sociology, Social at Queen's 1 Canada Room/Council Chamber 13 Careers, Employability and Skills 24 Centre for Cancer Research Building 1n Development and Alumni Relations 13 Disability Services 8 Drama and Film Centre at Queen's (inc

Müller, Jens-Dominik

218

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

219

SONY GXB5005 GPS RECEIVER DATA Without shield can Installed With shield can in place  

E-print Network

for WAAS/EGNOS augmented positioning. The receiver is based on Sony's CXD2951 single-chip GPS receiver ICSONY GXB5005 GPS RECEIVER DATA Without shield can Installed With shield can in place (for illustrative purposes only) The Sony GXB5005 GPS receiver is a miniature 12 channel GPS module with support

Berns, Hans-Gerd

220

UWB: Success in AircraftUWB: Success in Aircraft Shielding MetrologyShielding Metrology  

E-print Network

UWB: Success in AircraftUWB: Success in Aircraft Shielding MetrologyShielding Metrology Dr. Robert in UWB metrology have been existence since 1971--both conducted & radiated · Low-power & low interference processing · NASA: Shuttle safety during night launches · Boeing: protection of flight platforms with high

Southern California, University of

221

40. SOUTHWEST CORNER OF STAGE SHOWING RIGGING FOR FLYING SETS, ...  

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

40. SOUTHWEST CORNER OF STAGE SHOWING RIGGING FOR FLYING SETS, LOCATION OF ORIGINAL DOORS IN PROSCENIUM WALL, AND COUNTERWEIGHTS FOR STAGE CURTAIN. - Auditorium Building, 430 South Michigan Avenue, Chicago, Cook County, IL

222

25. DETAIL OF TIE ROD REINFORCING BELOW WESTERNMOST MOVABLE STAGE ...  

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

25. DETAIL OF TIE ROD REINFORCING BELOW WESTERNMOST MOVABLE STAGE SECTION, LOWER LEVEL OF STAGE, LOOKING SOUTH. TAKEN FROM A POINT JUST SOUTH OF RAM IN IL-1007-24. - Auditorium Building, 430 South Michigan Avenue, Chicago, Cook County, IL

223

118. Stage basement. View, facing south, of the south hydraulic ...  

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

118. Stage basement. View, facing south, of the south hydraulic ram (type D) in the middle row. Photo was taken before the stage flooring was removed. - Auditorium Building, 430 South Michigan Avenue, Chicago, Cook County, IL

224

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

225

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

226

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

227

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

228

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

229

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

230

Space reactor shielding: an assessment of the technology  

SciTech Connect

Space power reactor systems require shielding to protect payload and reactor shielding components, and also maintenance and operating personnel. Shield composition, size, and shape are important design considerations, since the shield can dominate the overall weight of the system. Techniques for space reactor shield design analysis and optimization and experimental test facilities are available for design verification. With these tools, a shielding technology in support of current and future space power reactor systems can be developed. Efforts in this direction should begin with a generic shielding program to provide information on materials properties and geometric effects and should be followed by project-specific shielding programs to provide design optimization and prototype shield verification.

Bartine, D.E.; Engle, W.W. Jr.

1982-01-01

231

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

232

Starprobe thermal shield system design concepts  

NASA Technical Reports Server (NTRS)

The mission goals, flight trajectory, and material durability requirements for the NASA Starprobe spacecraft are reviewed. The spacecraft will use a Jovian gravity assist to pass within four solar radii of the sun to study fields and particles near the sun, perform experiments dealing with relativity and gravity, and observe the structure of the solar atmosphere from the photosphere to the corona. Constraints on the system size and mass design are given, and the system is noted to be required to withstand 2500 K at perihelion, thermally insulate the instrument payload, have a tube for optical measurements, and provide protection from meteorite damage. A secondary shield is also required to dispense thermal radiation that passes the primary shield and could endanger the payload. Design options are discussed, along with temperature control requirements and a conical carbon-carbon primary shield with mass-loss rate characteristics sufficient to meet a 2.5 mg/sec criterion.

Maag, C. R.; Millard, J. M.; Miyake, R. N.

1982-01-01

233

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

234

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

235

Shakespeare's Staging  

NSDL National Science Digital Library

The University of California at Berkeley's English Department has undertaken the enormous task of presenting "a survey of current information, opinions and visuals about...the original nature of Shakespearean performance during his lifetime, and of its development through four centuries thereafter." Visitors can click on "Performance Galleries" at the top of the homepage to be taken to ten albums of over 900 images. Some of the topics of the albums that you can link to are "Productions from the Sixteenth through the Twentieth Century", "Productions in Britain 1960-1998", and "Unusual Representations of Shakespeare Performances". The albums contain items such as playbills, photos and drawings of performances, and photos of the rebuilt Globe Theatre. On the far left side of the homepage, visitors can click on "Videos" to view a documentary series about Elizabethan life, as well as excerpts of performances staged by the Shakespeare Program of UC Berkeley at Shakespeare's Globe Theatre. The videos can be viewed by "Latest", "Most Viewed", "Highest Rated", and "Featured". Visitors interested in other websites that explore Shakespeare performance will want to click on "Relevant Websites" on the far left side of the homepage, to access a link that has 27 Shakespeare performance related websites.

236

Numerical simulation of space debris impacts on the Whipple shield  

NASA Astrophysics Data System (ADS)

The authors carried out three series of experimental tests of the first bumper perforation and main wall cratering processes directly caused by three types of projectiles with about 2, 4 and 7 km s -1 impact velocities but comparable initial kinetic energies, by using three different accelerators (one-stage powder gun, two-stage light-gas gun and rail gun), for the purpose of investigating space debris hypervelocity impacts onto single-walled Whipple bumper shields [1]. In the present study, after reviewing the numerical simulation method of hydrocode for both Eulerian and Lagrangian descriptions, a number of parametric numerical simulation analyses using multiple material Eulerian methods were performed in order to optimize the material properties of bumper and main wall materials through comparison with experimental results of single target impacts by the projectiles. In particular, the material data on the dynamic fracture phenomena are discussed in detail in the first part. Then a couple of numerical calculations using the interactive Lagrangian rezoning method to simulate the overall impact process against the single walled Whipple shield were performed and compared with the corresponding experimental results. Both results indicated fairly good agreement with each other. Moreover, it was demonstrated that the present method is helpful and efficient in understanding the impact phenomena and fracture mechanism in the space debris hypervelocity impact problem. Finally the multiple material Eulerian method was applied to the same problems modeled by the interactive Lagrangian rezoning method used previously, because the former is much easier to use for almost all users, although it is more diffusive and unclear of material boundaries than the latter. Those two kinds of numerical results also indicated fairly good agreements with each other.

Katayama, M.; Toda, S.; Kibe, S.

1997-06-01

237

Parametrically shielding electromagnetic fields by nonlinear metamaterials.  

PubMed

An analytical theory is developed for parametric interactions in metamaterial multilayer structures with simultaneous nonlinear electronic and magnetic responses and with a near-zero refractive index. We demonstrate theoretically that electromagnetic fields of certain frequencies can be parametrically shielded by a nonlinear left-handed material slab, where the permittivity and permeability are both negative. The skin depth is tunable, and even in the absence of material absorption, can be much less than the wavelength of the electromagnetic field being shielded. This exotic behavior is a consequence of the intricate nonlinear response in the left-handed materials and vanishing optical refractive index at the pump frequency. PMID:18352472

Feng, Simin; Halterman, Klaus

2008-02-15

238

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.

1997-01-01

239

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

240

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

241

Analytical study of twin-jet shielding  

NASA Technical Reports Server (NTRS)

Progress in the refinement and evaluation of an analytical jet shielding model are summarized. The model consists of a point noise source impinging on a cylinder of heated flow in which the temperature and velocity are uniform across the cross section of the jet. The shielding jet is infinite in extent along the jet axis and the radius of the jet is constant. The analytical model was compared to experimental data for a point noise source impinging on an ambient temperature, subsonic jet and on a subsonic simulated hot jet using helium as the flow medium. Results of these comparisons are discussed.

Gerhold, C. H.

1982-01-01

242

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

243

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

244

Isotopic composition of phanerozoic ore leads from the Swedish segment of the Fennoscandian Shield  

Microsoft Academic Search

95 analyses of ore lead isotope ratios from 23 Phanerozoic ore deposits from the Swedish segment of the Fennoscandian Shield form a marked linear trend on a 207Pb\\/204Pb versus 206Pb\\/204Pb diagram. The line may be interpreted in a two-stage model, the lead being derived from 1.8±0.15 Ga old Svecokarelian basement and mineralization occurring at 0.4±0.15 Ga. The initial composition of

Åke Johansson; David Rickard

1984-01-01

245

Desert Shield and Desert Storm Emerging Observations.  

National Technical Information Service (NTIS)

The enclosed final report is the culmination of the U.S. Army Armor Center effort to collect Desert Shield/Storm emerging observations and provide them to the Total Armor Force (TAF) and other selected agencies. The report is a compilation of a year long ...

1991-01-01

246

SHLDUTIL: A Code for Useful Shielding Data  

E-print Network

SHLDUTIL: A Code for Useful Shielding Data by J. Kenneth Shultis and Richard E. Faw (jks equivalents H (10mm) and H (.07mm) 5. ICRP (1996) dose indices and ambient dose equivalents H (10mm) and H) prescribed dose equivalent (NCRP 1971) 2. ICRP (1987) dose indices and ambient dose equivalents H (10mm

Shultis, J. Kenneth

247

Shielding Integral Benchmark Archive and Database (SINBAD)  

Microsoft Academic Search

The Shielding Integral Benchmark Archive and Database (SINBAD) collection of benchmarks was initiated in the early 1990s. SINBAD is an international collaboration between the Organization for Economic Cooperation and Development's Nuclear Energy Agency Data Bank (OECD\\/NEADB) and the Radiation Safety Information Computational Center (RSICC) at Oak Ridge National Laboratory (ORNL). SINBAD is a major attempt to compile experiments and corresponding

Bernadette Lugue Kirk; Robert E Grove; I. Kodeli; Enrico Sartori; J. Gulliford

2011-01-01

248

Shielding effectiveness of superconductive particles in plastics  

Microsoft Academic Search

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

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

1988-01-01

249

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

250

Beer and Economic Growth Dr. Martin Shields  

E-print Network

Beer and Economic Growth Dr. Martin Shields Regional Economics Institute Colorado State University to the rest of the world #12;Industry Trends · Over the past 10 years, the growth in craft beer has significantly altered the industry · While overall beer sales are relatively flat, market share of craft brewers

251

Topographic evidence for shield volcanism on Io  

Microsoft Academic Search

Similarities between terrestrial shield volcanoes and a volcano on Io observed in Voyager I imagery of the satellite at 30° S, 246° 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

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

1986-01-01

252

Topographic evidence for shield volcanism on Io  

Microsoft Academic Search

Similarities between terrestrial shield volcanoes and a volcano on Io observed in Voyager I imagery of the satellite at 30 deg S, 246 deg 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

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

1986-01-01

253

Evolution of large shield volcanoes on Venus  

Microsoft Academic Search

We studied the geologic history, topographic expression, and gravity signature of 29 large Venusian shield volcanoes with similar morphologies in Magellan synthetic aperture radar imagery. While they appear similar in imagery, 16 have a domical topographic expression and 13 have a central depression. Typical dimensions for the central depression are 150 km wide and 500 m deep. The central depressions

Robert R. Herrick; Josef Dufek; Patrick J. McGovern

2005-01-01

254

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

255

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

256

Guided modes in shielded slot transmission line  

Microsoft Academic Search

Guided modes in a shielded slot transmission line were analyzed. This transmission line consists of slotted metal strips inserted in a below cutoff parallel metal plate waveguide. The TEM mode can propagate in the slot area as the lowest dominant mode, while the higher modes may propagate in the metal strip regions from the calculated results based on the transverse

Futoshi KUROKI; Kazuya MIYAMOTO

2006-01-01

257

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

258

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

259

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

260

Crack Tip Shielding or Anti-shielding due to Smooth and Discontinuous Material Inhomogeneities  

Microsoft Academic Search

This paper describes a theoretical model and related computational methods for examining the influence of inhomogeneous material\\u000a properties on the crack driving force in elastic and elastic-plastic materials. Following the configurational forces approach,\\u000a the crack tip shielding or anti-shielding due to smooth (e.g. graded layer) and discontinuous (e.g. bimaterial interface)\\u000a distributions in material properties are derived. Computational post-processing methods are

N. K. Simha; F. D. Fischer; O. Kolednik; J. Predan; G. X. Shan

2005-01-01

261

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

2012-06-07

262

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

263

Apparatus and Method for Deploying a Hypervelocity Shield  

NASA Technical Reports Server (NTRS)

Provided herein are apparatuses for deployment of at least one hypervelocity shield on a structure in exoatmospheric space. The apparatuses comprise a means of attaching to the structure at least at one place on the structure and further comprise at least one of the hypervelocity shields and a means of deploying said shields. Also provided are methods of deploying the hypervelocity shields using said apparatuses.

Christiansen, Eric L. (Inventor); Kerr, Justin H. (Inventor)

2003-01-01

264

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

265

Second Stage Separation  

NASA Video Gallery

When the second stage burn is complete, the spacecraft and third stage are spun up to 55 rpm to stabilize the third stage during its short firing. The second stage is then jettisoned and the third ...

266

Numerical Study of Noise Shielding by Airframe Structures Changzheng Huang*  

E-print Network

-quiet advent aircraft that use jet noise shielding by the airframe. Current methods to predict shielding from predictive tools for jet noise shielding therefore requires a different approach. In this study we use, we examine the interaction of a wavepacket ­ simulating the jet noise source ­ with a rectangular

Papamoschou, Dimitri

267

EMI shielding evaluations of carbon nanotube based coatings and applications  

Microsoft Academic Search

Electromagnetic interference (EMI) shielding coatings based on carbon nanotube (CNT) has been prepared and evaluated. The electromagnetic shielding effectiveness is measured using planar material fixture method from 10MHz to 3 GHz and with free space method in the range of 3 GHz to 18 GHz. The results show that carbon nanotube based coating is effective in providing EMI shielding in

Ping Li; Yueyan Shan; Lie Liu; Junhong Deng; Ong Guat Choon; Xijiang Yin

2012-01-01

268

Broadband EMI shielding for electro-optical systems  

Microsoft Academic Search

Electromagnetic interference (EMI) shielding of apertures in electro-optical (EO) systems can be accomplished generally by transparent electrically conductive (EC) coatings, wire meshes or opaque EC coatings patterned to form meshes. The shielding effectiveness (SE) of these methods are studied both analytically and experimentally. The shielding due to both absorption and reflection as a function of frequency was evaluated. EO systems

C. I. Bright

1994-01-01

269

Electromagnetic shielding for electro-optical windows and domes  

Microsoft Academic Search

Electromagnetic interference (EMI) shielding of windows and domes in electro-optical (EO) systems can be accomplished by transparent electrically conductive (EC) coatings or patterned opaque EC coatings. The shielding effectiveness (SE) of these two methods was studied both analytically and experimentally. Shielding due to both absorption and reflection as a function of frequency was evaluated. Infrared EO systems often use windows

Clark I. Bright

1994-01-01

270

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

271

Building Resonance  

NSDL National Science Digital Library

This demonstration of how buildings respond to seismic shaking uses cardboard and stiff paper (such as postcards or computer cards). The effects of building resonance can be found by experimenting with taller and shorter buildings, and varying the frequency of shaking.

Barker, Jeffrey

272

Modeling of plume dynamics with shielding in laser ablation of carbon  

NASA Astrophysics Data System (ADS)

The process of laser ablation of carbon in presence of background gas is simulated numerically. The plume dynamics in laser ablation is important to study for many reasons including temperature of plume particles and shielding of target by previously ablated plumes. Shielding leads directly to the change in energy deposition of incident laser pulse at the target surface and in turn influences the ablation dynamics and amount of material removed. Carbon ablation is studied for single and multiple laser hits typical for synthesis of nanotubes. Two models of correction of ablated velocity and pressure resulting from shielding effect are proposed and investigated. Numerical modeling of this plume dynamics and its integral effect of shielding is challenging due to inherent high nonlinearity of the problem. Some of available numerical techniques handles nonlinearity but are dissipative, e.g. Godunov type schemes. Other techniques are less dissipative but fail to account for strong nonlinearity typical for initial stages of ablation, e.g. the ENO-Roe. To effectively model this highly nonlinear plume dynamics a combination of two of above mentioned schemes is developed so as the numerical evaluation of fluxes is close to their physical values and the scheme has minimum dissipation. The non-monotonic behavior of ablated mass as a function of time duration between two laser pulses is studied.

Pathak, Kedar; Povitsky, Alex

2007-05-01

273

Early-Stage Caregiving  

MedlinePLUS

... alz.org » Caregiver Center » Stages & Behaviors » Caring for Early-Stage Alzheimer's Text size: A A A Stages Early-Stage ... partner in this stage varies. A person with early-stage Alzheimer's may need cues and reminders to help with ...

274

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

275

Space radiation shielding strategies and requirements for deep space missions  

NASA Technical Reports Server (NTRS)

Methods for estimating crew exposure to radiation and for evaluating shield requirements for spacecraft equipment and crew are examined. The development status for deterministic space radiation transport computer codes and models of their nuclear interaction inputs, which are useful for estimating the composition and thickness of shield materials, is discussed. The relation between shield thickness and exposures is studied. Estimates of deep-space shield requirements are proposed. It is noted that an assessment of input parameter uncertainties reveals that a factor of 2 uncertainty in predicted dose equivalent could increase shield thickness by an order of magnitude of more.

Townsend, Lawrence W.; Wilson, John W.; Nealy, John E.

1989-01-01

276

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

277

Electromagnetic shielding for electro-optical windows and domes  

NASA Astrophysics Data System (ADS)

Electromagnetic interference (EMI) shielding of windows and domes in electro-optical (EO) systems can be accomplished by transparent electrically conductive (EC) coatings or patterned opaque EC coatings. The shielding effectiveness (SE) of these two methods was studied both analytically and experimentally. Shielding due to both absorption and reflection as a function of frequency was evaluated. Infrared EO systems often use windows or domes made of semiconductive material. These semiconductive materials also provide some EMI shielding for the system. The SE of some typical exemplary semiconductive windows was calculated. The broadband shielding benefits of using EC coatings deposited on semiconductive window substrates were examined.

Bright, Clark I.

1994-09-01

278

Radiation shielding design considerations for Doublet III  

SciTech Connect

Calculations and measurements were made of the bremsstrahlung (x-ray) doses resulting from runaway electron shots at Doublet III. The analysis considered direct, wall-scattered, and skyshine contributions. Reasonably good agreement was obtained between calculations and measurements. The x-ray dose in the control room was about 1 mR per runaway shot, while that at the north boundary was undetectable, with a calculated value of 0.05 mR per shot. These low doses attest to the adequacy of the 2 ft concrete shadow shield surrounding the Doublet III room. Exploratory shielding analyses were performed for possible neutron generation if Doublet III were operated with neutral beam injection in an aggressive D-D mode.

Engholm, B.A.

1980-06-01

279

Active Neutron Shielding for Dark Matter Searches  

NASA Astrophysics Data System (ADS)

Neutrons are a dangerous background to direct dark matter detection searches because they can mimic exactly the signal signature. Recent studies find that the few existing underground measurements of the fast, muon-induced neutron flux disagree at the 30%-50% level with predictions. Given this level of uncertainty, it is desirable to measure the neutron flux in-situ, as well as to reduce the number of neutrons incident on a dark matter detector. Towards these ends, we are developing a neutron veto system for both active and passive shielding. The goals of this R&D are (i) a measurement of the neutron energy spectrum underground above 10 MeV neutron kinetic energies, and (ii) measurements of the attenuation vs. energy of these neutrons in 1 meter of water, concrete, and liquid scintillator. These measurements will provide valuable input for simulation and design of shields for low-background experiments underground.

Monroe, Jocelyn; Yamamoto, Richard; Fisher, Peter; Cornell, Brett; Robinson, Mareena; Cowern, Dianna; Eyers, Richard; Henderson, Shawn

2009-05-01

280

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

281

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

282

Structural and Radiation Shielding Properties of a Martian Habitat Material Synthesized From In-Situ Resources  

NASA Technical Reports Server (NTRS)

The 2 primary requirements of a Martian habitat structure include sufficient structural integrity and effective radiation shielding. In addition, the capability to synthesize such building materials primarily from in-situ resources would significantly reduce the cost associated with transportation of such materials and structures from earth. To demonstrate the feasibility of such an approach we have fabricated samples in the laboratory using simulated in-situ resources, evaluated radiation shielding effectiveness using radiation transport codes and radiation test data, and conducted mechanical properties testing. In this paper we will present experimental results that demonstrate the synthesis of polyethylene from a simulated Martian atmosphere and the fabrication of a composite material using simulated Martian regolith with polyethylene as the binding material. Results from radiation transport calculations and data from laboratory radiation testing using a 500 MeV/nucleon Fe beam will be discussed. Mechanical properties of the proposed composite as a function of composition and processing parameters will also be presented.

Sen, S.; Caranza, S.; Bhattacharya, M.; Makel, D. B.

2006-01-01

283

CFB Goose Bay and Operation “Desert Shield”  

Microsoft Academic Search

Canada committed forces to the American-led Coalition in the 1990–1991 campaign to liberate Kuwait (Operation DESERT SHIELD and Operation DESERT STORM). The Navy played an important role in the naval portion in this campaign known as Operation DESERT STORM. Canadian CF-18s provided defensive combat air patrols over the Persian Gulf region (less Kuwait and Iraq). Canadian soldiers helped guard prisoners

James R. McKay

2012-01-01

284

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

285

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

286

SINBAD: Shielding integral benchmark archive and database  

SciTech Connect

SINBAD is a new electronic database developed to store a variety of radiation shielding benchmark data so that users can easily retrieve and incorporate the data into their calculations. SINBAD is an excellent data source for users who require the quality assurance necessary in developing cross-section libraries or radiation transport codes. The future needs of the scientific community are best served by the electronic database format of SINBAD and its user-friendly interface, combined with its data accuracy and integrity.

Hunter, H.T.; Ingersoll, D.T.; Roussin, R.W. [and others

1996-04-01

287

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

288

Sandwich composite approach for EMI shielding structures  

Microsoft Academic Search

A sandwich composite approach has been employed to develop epoxy based polymer matrix composite materials to realize a class of lightweight structures capable of shielding electromagnetic interference (EMI). Hollow glass microspheres embedded syntactic foams (thickness ap 2 mm; density ap 0.6 g\\/cc) of two different varieties have been used as core materials in these sandwich constructions (total thickness ap 2.6

S. Dasgupta; K. Ravi Sekhart; B. N. Ravishankar; M. Kumar; S. Sankaran

2008-01-01

289

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

290

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

291

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

292

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

293

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.

294

Utilization of recycled cathode ray tubes glass in cement mortar for X-ray radiation-shielding applications.  

PubMed

Recycled glass derived from cathode ray tubes (CRT) glass with a specific gravity of approximately 3.0 g/cm(3) can be potentially suitable to be used as fine aggregate for preparing cement mortars for X-ray radiation-shielding applications. In this work, the effects of using crushed glass derived from crushed CRT funnel glass (both acid washed and unwashed) and crushed ordinary beverage container glass at different replacement levels (0%, 25%, 50%, 75% and 100% by volume) of sand on the mechanical properties (strength and density) and radiation-shielding performance of the cement-sand mortars were studied. The results show that all the prepared mortars had compressive strength values greater than 30 MPa which are suitable for most building applications based on ASTM C 270. The density and shielding performance of the mortar prepared with ordinary crushed (lead-free) glass was similar to the control mortar. However, a significant enhancement of radiation-shielding was achieved when the CRT glasses were used due to the presence of lead in the glass. In addition, the radiation shielding contribution of CRT glasses was more pronounced when the mortar was subject to a higher level of X-ray energy. PMID:22118845

Ling, Tung-Chai; Poon, Chi-Sun; Lam, Wai-Shung; Chan, Tai-Po; Fung, Karl Ka-Lok

2012-01-15

295

Building Houses  

NSDL National Science Digital Library

Build a house you can fit inside, using cardboard tubes. Variations of this activity include building for a toy (easier) or building a house the right size for a stuffed animal or a garage for a toy car. Also included is an option to build houses inspired by those around the world (harder). This activity focuses on the understanding of sizes and shapes: Can I fit in this if I stand up? if I sit? Do we have enough cardboard tubes to make a triangular roof? This activity is available as a webpage and a downloadable pdf. Students should have the ability to use scissors and tape well.

2010-01-01

296

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 âCan We Build It?(TM) Yes We Can!â 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) â Project: Build It" unit of study.

Indianapolis, The C.

2006-01-01

297

Optimizing the shielding effectiveness of a shielding cabinet via FEM simulation  

NASA Astrophysics Data System (ADS)

The magnetic shielding performance (SP) of a moderate-size shielding cabinet (SC) was examined using the finite element method (FEM) for the frequency range from DC to 1 kHz. The calculated data, as well as the experimental data, reveal that the conductive Al plate is crucial for frequency above 1 Hz, whereas the magnetic mumetal is indispensable below 1 Hz. The complex behavior of the mumetal in SP originates from a competition between eddy current losses and magnetic permeability evidenced by field distribution inside the SC. Demagnetization after assembly of the mumetal is important for the improvement in SP. The analysis of the experimental results in terms of a linear combination of the calculated individual components and the origin for the deviation between simulated and measured shielding factor (SF) are discussed in detail.

Kim, Wan-Seop; Kim, Yoon Bae; Kim, Mun-Seog; Kim, Kyu-Tae; Chong, Yonuk; Park, Po Gyu; Kim, Young Gyun

2007-09-01

298

Shielding aspects of D- sup 3 He fusion power reactors  

SciTech Connect

In this paper the implications of the D-{sup 3}He fuel cycle on shielding design are investigated for tokamak power reactors of the ARIES/Apollo class. The prime function of the shield is to protect the superconducting magnets against radiation. A variety of shield options is examined, and the various shields are optimized for the D-{sup 3}He neutron spectrum. The results demonstrate the relative merits of the various materials as a function of the shield thickness. In the first wall/shield, low-activation structural materials (such as Tenelon, modified HT-9, silicon carbide composites, and carbon-carbon composites) were employed to reduce the radioactive inventory and increase the safety margin in case of accidents. A comparison between the different shield options based on detailed neutronics, environmental/safety, and economic assessments has led to the selection of the reference shield design. The first-wall/shield structure is made of an elementally tailored ferritic steel (MHT-9), and the thermal energy is converted through an organic coolant at 44% efficiency. The safety features of the low-activation steel shield, along with the low neutron production in the D-{sup 3}He fuel cycle, enable the ARIES-III/Apollo design to achieve acceptable environmental and safety characteristics.

El-Guebaly, L.A. (Wisconsin Univ., Madison, WI (United States). Fusion Technology Inst.)

1992-08-01

299

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.

300

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 ...

301

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 ...

302

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

303

Early shielding research at Bettis Atomic Power Laboratory  

SciTech Connect

Reminiscences of shielding research at Bettis Atomic Power Laboratory (BAPL) always have in the background the reason for its existence - the design of efficient and safe reactors. Shielding is essential for personnel safety. However, the only computational tools available in the early 1950s were slide rules and desk calculators. Under these conditions, any shield desing calculation accurate within a factor of 2 was a good one, and the phrases close enough for shielding purposes' and including a factor for conservation' became a permanent part of the shielding vocabulary. This early work instilled a respect for hand calculations and the requirements that nay result, no matter how calculated, must meet the test of being reasonable and in line with previous experience. Even today, with sophisticated shielding programs available on the latest computers, calculated results must pass the same test.

Shure, K.; Wallace, O.J. (Westinghouse Electric Corp., West Mifflin, PA (United States))

1992-01-01

304

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

305

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

306

Radiation shielding for underground low-background experiments  

SciTech Connect

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. Note that these proceedings are a short version of a recently submitted, more detailed discussion.

Stewart, D. Y.; Harrison, P. F.; Morgan, B.; Ramachers, Y. [University of Warwick, Coventry, CV4 7AL (United Kingdom)

2006-11-17

307

Shielding Design of the Spallation Neutron Source (SNS)  

SciTech Connect

The shielding design is important for the construction of an intense high-energy accelerator facility like the proposed Spallation Neutron Source (SNS) due to its impact on conventional facility design, maintenance operations, and since the cost for the radiation shielding shares a considerable part of the total facility costs. A calculational strategy utilizing coupled high energy Monte Carlo calculations and multi-dimensional discrete ordinates calculations, along with semi-empirical calculations, was implemented to perform the conceptual design shielding assessment of the proposed SNS. Biological shields have been designed and assessed for the proton beam transport system and associated beam dumps, the target station, and the target service cell and general remote maintenance cell. Shielding requirements have been assessed with respect to weight, space, and dose-rate constraints for operating, shutdown, and accident conditions. A discussion of the proposed facility design, conceptual design shielding requirements, calculational strategy, source terms, preliminary results and conclusions, and recommendations for additional analyses are presented.

Johnson, J.O.

1998-09-17

308

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, Rick B. (Albuquerque, NM)

1996-01-01

309

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

310

Martian regolith as space radiation shielding  

NASA Astrophysics Data System (ADS)

Mars exploration crews will be exposed to such high radiation dosages in route from earth that as to sharply reduce the allowable dose they should receive while on the Martian surface. An account is presently given of the possibility of using Martian regolith as crew shielding to maintain very low short-term dose limits. NASA-Langley's nucleon and heavy-ion transport computer codes are used to predict the propagation and interaction of the free-space nucleons and heavy ions through the Martian atmosphere and then through various thicknesses of regolith. The largest reduction in dose occurs in the first 15-20 cm of regolith material.

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

1991-02-01

311

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

312

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

313

BUILDINGS, CIVIL ENGINEERING AND SERVICES, 7 Gev PS  

Microsoft Academic Search

The various buildings for the 7-Bev proton synchrotron and their ; functions are discussed. Civil engineering information for sub-soil, magnet ; room, injector room, shielding bridge, and tunnels is listed. Electrical ; services, plant cooling, handling facilities, and general services are described. ; (W.D.M.);

G. W. Dixon; A. G. Entwistle

1959-01-01

314

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

315

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

316

Major uncertainties influencing entry probe heat shield design  

NASA Technical Reports Server (NTRS)

Factors influencing the design of an outer planet probe heat shield are discussed. Major factors included are: uncertainties in composition and scale height of the planet atmospheres; the augmentation/attenuation of entry heating by ablation products requires more computer study and testing; carbon heat shields, especially carbon phenolic, possessing improved resistance to spallation need developing; and white silica reflecting heat shields with improved resistance to bulk vitrification need further developing.

Congdon, W.

1974-01-01

317

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

318

BrowserShield: Vulnerability-driven filtering of dynamic HTML  

Microsoft Academic Search

Abstract Vulnerability-driven filtering of network data can offer a fast and easy-to-deploy alternative or intermediary to software patching, as exemplified in Shield [43]. In this paper, we take Shield’s vision to a new domain, inspect- ing and cleansing not just static content, but also dy- namic,content. The dynamic,content we target is the dynamic HTML in web pages, which have become

Charles Reis; John Dunagan; Helen J. Wang; Opher Dubrovsky; Saher Esmeir

2007-01-01

319

Life test and electromagnetic shielding performance evaluation of EMI gaskets  

Microsoft Academic Search

MIL-G-83528B, ASTM 4935-89 and JSS 52100 are some of the specifications used in evaluating the performance of EMI\\/RFI\\/EMP gaskets. These gaskets are used to maintain the electromagnetic (EM) shielding integrity in shielded enclosures. A number of test methods are being developed and evaluated to measure accurately EM shielding or volume resistivity of the test samples before and after life test.

A. K. Subramanian; D. C. Pande; K. Boaz

1995-01-01

320

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

321

LOFT. West side of containment building and dome (TAN650). Camera ...  

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

LOFT. West side of containment building and dome (TAN-650). Camera is atop earth -shield control building (TAN-630), facing east. Vertical structure at right of view (with light affixed) is west end of railroad door shroud. Date: May 2004. INEEL negative no. HD-39-19-1 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID

322

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

323

SHIELDING ANALYSIS FOR PORTABLE GAUGING COMBINATION SOURCES  

SciTech Connect

Radioisotopic decay has been used as a source of photons and neutrons for industrial gauging operations since the late 1950s. Early portable moisture/density gauging equipment used Americium (Am)-241/Beryllium (Be)/Cesium (Cs)-137 combination sources to supply the required nuclear energy for gauging. Combination sources typically contained 0.040 Ci of Am-241 and 0.010 Ci of CS-137 in the same source capsule. Most of these sources were manufactured approximately 30 years ago. Collection, transportation, and storage of these sources once removed from their original device represent a shielding problem with distinct gamma and neutron components. The Off-Site Source Recovery (OSR) Project is planning to use a multi-function drum (MFD) for the collection, shipping, and storage of AmBe sources, as well as the eventual waste package for disposal. The MFD is an approved TRU waste container design for DOE TRU waste known as the 12 inch Pipe Component Overpack. As the name indicates, this drum is based on a 12 inch ID stainless steel weldment approximately 25 inch in internal length. The existing drum design allows for addition of shielding within the pipe component up to the 110 kg maximum pay load weight. The 12 inch pipe component is packaged inside a 55-gallon drum, with the balance of the interior space filled with fiberboard dunnage. This packaging geometry is similar to the design of a DOT 6M, Type B shipping container.

J. TOMPKINS; L. LEONARD; ET AL

2000-08-01

324

SHIELDING REQUIREMENTS FOR NSLS-II.  

SciTech Connect

Brookhaven National Laboratory is in the process of designing a new Electron Synchrotron for scientific research using synchrotron radiation. This facility, called the 'National Synchrotron Light Source II' (NSLS-II), will provide x-ray radiation of ultra-high brightness and exceptional spatial and energy resolution. It will also provide advanced insertion devices, optics, detectors, and robotics, and a suite of scientific instruments designed to maximize the scientific output of the facility. The project scope includes the design, construction, installation, and commissioning of the following accelerators: a 200 MeV linac, a booster accelerator operating from 200 MeV to 3.0 GeV, and the storage ring which stores a maximum of 500 mA current of electrons at an energy of 3.0 GeV. It is planned to operate the facility primarily in a top-off mode, thereby maintaining the maximum variation in stored beam current to < 1%. Because of the very demanding requirements for beam emittance and synchrotron radiation brilliance, the beam life-time is expected to be low, on the order of 2-3 hours. Analysis of the bulk shielding for operating this facility and the input parameters used for this analysis are discussed in this paper. The characteristics of each of the accelerators and their operating modes are summarized with the input assumptions for the bulk shielding analysis.

JOB,P.K.; CASEY, W.R.

2008-01-02

325

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

326

Heat flow from the Liberian Precambrian Shield  

NASA Astrophysics Data System (ADS)

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-2. When corrections are applied for topography and refraction, the range of heat flow is narrowed to between 38 and 42 mW m-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-2) and Nigeria (38±2 mW m-2) but are somewhat higher than values from Niger (20 mW m-2) and neighboring Sierra Leone (26 mW m-2). The Liberian values are significantly lower than the heat flow offshore in the equatorial Atlantic Ocean (58±8 m W m-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 /?W m-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-2 is consistent with that from other Precambrian shields.

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

1980-06-01

327

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

328

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

329

Deoxyribonucleic acid-Ag nanoparticles for EMI Shielding: the effect of nanoparticle size, shape and distribution on the shielding effectiveness  

NASA Astrophysics Data System (ADS)

This study focuses on the use of silver based nanoparticle as fillers in DNA host materials to form nancomposites for applications in Electro-Magnetic Interferences (EMI) shielding. For relatively low-conductivity EMI shielding nanocomposites, silver-oxide coated cenospheres are investigated as fillers. The filler loadings are varied to determine a percolation threshold for the desired low conductivity and shielding effectiveness. Microwave absorption as well as DC surface resistivity measurements are undertaken to characterize the obtained films.

Ouchen, Fahima; Wilson, Benjamin G.; Yaney, Perry P.; Salour, Michael M.; Grote, James G.

2014-09-01

330

Ares I Stage Separation Test  

NASA Technical Reports Server (NTRS)

Under the goals of the Vision for Space Exploration, Ares I is a chief component of the cost-effective space transportation infrastructure being developed by NASA's Constellation Program. This transportation system will safely and reliably carry human explorers back to the moon, and then onward to Mars and other destinations in the solar system. The Ares I effort includes multiple project element teams at NASA centers and contract organizations around the nation, and is managed by the Exploration Launch Projects Office at NASA's Marshall Space Flight Center (MFSC). ATK Launch Systems near Brigham City, Utah, is the prime contractor for the first stage booster. ATK's subcontractor, United Space Alliance of Houston, is designing, developing and testing the parachutes at its facilities at NASA's Kennedy Space Center in Florida. NASA's Johnson Space Center in Houston hosts the Constellation Program and Orion Crew Capsule Project Office and provides test instrumentation and support personnel. Together, these teams are developing vehicle hardware, evolving proven technologies, and testing components and systems. Their work builds on powerful, reliable space shuttle propulsion elements and nearly a half-century of NASA space flight experience and technological advances. Ares I is an inline, two-stage rocket configuration topped by the Crew Exploration Vehicle, its service module, and a launch abort system. In this HD video image, an Ares I x-test involves the upper stage separating from the first stage. This particular test was conducted at the NASA Langley Research Center in July 2007. (Highest resolution available)

2007-01-01

331

Building debris  

E-print Network

This thesis relates architectural practices to intelligent use of resources and the reuse of derelict spaces. The initial investigation of rammed earth as a building material is followed by site-specific operations at the ...

Dahmen, Joseph (Joseph F. D.)

2006-01-01

332

Library Buildings  

ERIC Educational Resources Information Center

Examines a century of library architecture in relation to the changing perceptions of library functions, the development of building techniques and materials, fluctuating esthetic fashions and sometimes wildly erratic economic climates. (Author)

Allen, Walter C.

1976-01-01

333

Building Sandcastles  

NSDL National Science Digital Library

In this interactive application young children become familiar with 3-dimensional shapes by matching a variety of shapes in order to build a sandcastle. There are two levels of play, parent pointers, and hints to help out along the way.

2014-01-01

334

Team Building  

NSDL National Science Digital Library

Employee involvement, teams, and employee empowerment enable people to make decisions about their work. This employee involvement, teambuilding approach, and employee empowerment increases loyalty and fosters ownership. These links tell you how to do team building and effectively involve people.

About.com (About.com)

2011-08-18

335

Better Buildings  

E-print Network

on capital ? Delaware State University secured construction financing via the Delaware Sustainable Energy Utility?s Energy Efficiency Construction Bonds for an energy services performance contract across 26 buildings that will result in 25 percent... on capital ? Delaware State University secured construction financing via the Delaware Sustainable Energy Utility?s Energy Efficiency Construction Bonds for an energy services performance contract across 26 buildings that will result in 25 percent...

Neukomm, M.

2012-01-01

336

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

337

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

338

Building Satellites is Easier  

NASA Technical Reports Server (NTRS)

'Building Satellites' is a story about Jim Marsh's recovery from a severe head injury told by his wife Phyllis from the moment she learned of its happening, through the ups and downs of a lengthy rehabilitation, until his return to work and daily living. It continues on, however, and narrates his battle with the more insidious Grave's disease. Told in the first person, 'Building Satellites' vividly portrays Phyllis's thoughts and feelings throughout this experience with scrupulous honestly. This is a story worth reading for many reasons. First of all, Jim was an accomplished scientist, respected by his colleagues both in this country and abroad. Secondly, it narrates the many stages of his recovery from head injury with detailed readable accuracy; it informs us as well as inspires. Finally, 'Building Satellites" also tells us the story of Phyllis Marsh's remarkable creative response to this crisis. It narrates her personal experiences as she progresses through the strange and somewhat bizarre world of medicine and rehabilitation, guided by a few basic beliefs, which she learned as a child in Iowa, that provided her with the strength to endure. 'Building Satellites' seems to reaffirm our unconscious, but settled conviction, that when confornted overnight with adversity, we are somehow given the means for coping, supported by our basic beliefs, strengthened by family and friends, and eventually learning to accept any outcome.

Marsh, Phyllis Nimmo

1996-01-01

339

116. Stage mezzanine level floor structure. North rams (type D), ...  

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

116. Stage mezzanine level floor structure. North rams (type D), facing south-southwest. The right hand ram is the same one visible from above in IL-1007-114. - Auditorium Building, 430 South Michigan Avenue, Chicago, Cook County, IL

340

Study on Shielding Failure Flashover Rate for EHV Transmission Line  

Microsoft Academic Search

Lightning is the main reason that endangers the safety and reliability of transmission line, but the existing models of estimating shielding failure flashover rate can not be in agreement with field experience at present. This paper deals with shielding failure flashover rate of the EHV transmission lines with many parameters by the improved electric-geometry model. The parameters consist of phase

Fan Chun-lei; Wu Guang-ning; Li Rui-fang

2008-01-01

341

Shield design, analysis, and testing to survive stainless steel projectiles  

Microsoft Academic Search

During the 3-year period of 1987 through 1989, the Advanced Shield Phenomenology Program included a research and development effort, with both experimental work and analytical support, to design a low weight, survivable shield against a stainless steel projectile at low earth orbit velocity. The specific threat used was a 1.75 gram, length to diameter ratio of one, stainless steel cylinder.

E. D. Brewer; W. R. Hendrich; D. G. Thomas; J. E. Smith

1990-01-01

342

Dielectric flashover with triple point shielding in a coaxial geometry.  

PubMed

Increasing performance of vacuum insulator barriers is a common goal in pulsed power. Insulating performance is continually being improved while new methods are developed. Triple point shielding techniques have been shown to increase flashover voltage, but the role of cathode versus anode shielding is still not fully understood. Open circuit flashover characteristics were obtained for a coaxial geometry to view the effects of triple point shielding for this geometry. The tests included applying various combinations of triple point shields on zero and +45 degrees insulators. Shielding was tested at the cathode triple point outside of the dielectric and at the anode triple point inside the dielectric. The role of anode versus cathode triple point shielding was examined. Flashover voltage was observed to increase when either a cathode or anode triple point shield was applied; however, adding a shield to both regions lowered the flashover threshold. Both triple point regions were found to be important and dependent on each other for some coaxial geometries. PMID:18052503

Benwell, A; Kovaleski, S D; Gahl, J

2007-11-01

343

Effect of an overhead shield on gamma-ray skyshine  

Microsoft Academic Search

A hybrid Monte Carlo and integral line-beam method is used to determine the effect of a horizontal slab shield above a gamma-ray source on the resulting skyshine doses. A simplified Monte Carlo procedure is used to determine the energy and angular distribution of photons escaping the source shield into the atmosphere. The escaping photons are then treated as a bare,

M. H. Stedry; J. K. Shultis; R. E. Faw

1996-01-01

344

IET. Periscope shielding and installation details. Shows range of scanning ...  

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

IET. Periscope shielding and installation details. Shows range of scanning head, removable concrete cap, concrete shielding. Ralph M. Parsons 902-4-ANP-620-A 324. Date: February 1954. Approved by INEEL Classification Office for public release. INEEL Index code no. 035-0620-00-693-106909 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID

345

Optimal shield mass distribution for space radiation protection  

NASA Technical Reports Server (NTRS)

Computational methods have been developed and successfully used for determining the optimum distribution of space radiation shielding on geometrically complex space vehicles. These methods have been incorporated in computer program SWORD for dose evaluation in complex geometry, and iteratively calculating the optimum distribution for (minimum) shield mass satisfying multiple acute and protected dose constraints associated with each of several body organs.

Billings, M. P.

1972-01-01

346

Shielding distribution for anisotropic radiation in low earth orbit  

Microsoft Academic Search

The highly directional nature of radiation encountered in low earth orbit (LEO) can be a basis for distributing mass for spacecraft radiation shielding. Trapped (Van Allen) radiation at low altitudes is concentrated within a plane perpendicular to the local geometric field lines. Trapped high-energy protons (which penetrate the relatively thin shielding required for electrons) have a pronounced east-west asymmetry at

M. W. Henley

1986-01-01

347

ORIGINAL ARTICLE Effect of bismuth breast shielding on radiation  

E-print Network

ORIGINAL ARTICLE Effect of bismuth breast shielding on radiation dose and image quality in coronary CT angiography Andrew J. Einstein, MD, PhD,a,b Carl D. Elliston, MA,c Daniel W. Groves, MD,a Bin angiography (CCTA) is associated with high radiation dose to the female breasts. Bismuth breast shielding

Brenner, David Jonathan

348

Development of copper-coated aluminum-shielded wire  

NASA Astrophysics Data System (ADS)

Aluminum-shielded wires are usually used in short lengths of about 200 millimeters in many electronic devices because of their easy termination. However, some problems have occurred in shield effect. The authors have found that this is due to the increase of contact resistance between the aluminum and the drain wire, which is caused by aluminum oxide. To overcome this problem, they developed a new shield tape composed of aluminum foil laminated with polyester film and having a copper layer over the aluminum face. The contact resistance between the shield tape and the drain wire could thus be reduced and was found to be very stable. A wire spirally wrapped and shielded with this new tape has very stable shield effect when subjected to a humid environment or H2S environment, even in short lengths of 100 mm. The authors also developed a new construction for the spirally wrapped shield which is very useful and reliable for multi-conductor wires having individually insulated and shielded conductors.

Saen, H.; Mori, A.

349

Development of copper-coated aluminum-shielded wire  

Microsoft Academic Search

Aluminum-shielded wires are usually used in short lengths of about 200 millimeters in many electronic devices because of their easy termination. However, some problems have occurred in shield effect. The authors have found that this is due to the increase of contact resistance between the aluminum and the drain wire, which is caused by aluminum oxide. To overcome this problem,

H. Saen; A. Mori

1983-01-01

350

Numerical Modeling of Periodic Composite Media for Electromagnetic Shielding Application  

E-print Network

materials with arbitrary micro-geometry and the shielding effects of using composite materials. KeywordsNumerical Modeling of Periodic Composite Media for Electromagnetic Shielding Application Dagang Wu electrical properties for periodic composite medium. The extraction algorithm is based on a periodic finite

Koledintseva, Marina Y.

351

FEM analysis and design bulb shield progressive draw die  

Microsoft Academic Search

Bulb shields are important components in the automobile headlamps and are primarily manufactured by progressive draw dies. Among progressive forming, multiple station progressive draw dies are the most formidable and thus among the most difficult of all progressive dies. Draw processes of a dome shape bulb shield are modeled and analyzed by FEM code DYNAFORM v5.2. Simulation prediction matches well

Z. Q. Sheng; R. Taylor; M. Strazzanti

2007-01-01

352

Description of transport codes for space radiation shielding.  

PubMed

Exposure to ionizing radiation in the space environment is one of the hazards faced by crews in space missions. As space radiations traverse spacecraft, habitat shielding, or tissues, their energies and compositions are altered by interactions with the shielding. Modifications to the radiation fields arise from atomic interactions of charged particles with orbital electrons and nuclear interactions leading to projectile and target fragmentation, including secondary particles such as neutrons, protons, mesons, and nuclear recoils. The transport of space radiation through shielding can be simulated using Monte Carlo techniques or deterministic solutions of the Boltzmann equation. To determine shielding requirements and to resolve radiation constraints for future human missions, the shielding evaluation of a spacecraft concept is required as an early step in the design process. To do this requires (1) accurate knowledge of space environmental models to define the boundary condition for transport calculations, (2) transport codes with detailed shielding and body geometry models to determine particle transmission into areas of internal shielding and at each critical body organ, and (3) the assessment of organ dosimetric quantities and biological risks by applying the corresponding response models for space radiation against the particle spectra that have been accurately determined from the transport code. This paper reviews current transport codes and analyzes their accuracy through comparison to laboratory and spaceflight data. This paper also introduces a probabilistic risk assessment approach for the evaluation of radiation shielding. PMID:23032892

Kim, Myung-Hee Y; Wilson, John W; Cucinotta, Francis A

2012-11-01

353

Effects of Source Redistribution on Jet Noise Shielding Salvador Mayoral*  

E-print Network

Effects of Source Redistribution on Jet Noise Shielding Salvador Mayoral* and Dimitri Papamoschou University of California, Irvine, CA 92697, USA The potential of jet noise shielding from the Hybrid Wing a thin flat plate, had the generic shape of the HWB planform. Redistribution of the jet noise source

Papamoschou, Dimitri

354

Designing space vehicle shields for meteoroid protection: A new analysis  

Microsoft Academic Search

Dual-layer meteroid shields consisting of sacrificial bumper plates spaced some distance outboard from the vehicle hull are the most effective structures yet conceived for protecting space vehicles from supervelocity meteroid impacts. This paper presents a new analysis for designing dual-layer shields. The analysis is based upon energy and momentum conservation, fundamental electromagnetic radiation physics, and observation of results from extensive

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

1982-01-01

355

Investigation of acoustical shielding by a wedge-shaped airframe  

Microsoft Academic Search

Experiments on a scale model of an advanced unconventional subsonic transport concept, the blended wing body (BWB), have demonstrated significant shielding of inlet-radiated noise. A computational model of the shielding mechanism has been developed using a combination of boundary integral equation method (BIEM) for source definition and equivalent source method (ESM) for scattering. In this way the sound fields with

Carl H. Gerhold; Lorenzo R. Clark; Mark H. Dunn; John Tweed

2006-01-01

356

Status report; Reactor shield codes for personal computers  

Microsoft Academic Search

This paper reports that as part of project to d develop a package of reactor physics codes for Personal Computers (PCs), the Idaho National Engineering Laboratory (INEL) is developing microcomputer versions of two reactor shielding codes that previously were available for mainframe computers only: QAD-CG and ANISN. QAD-CG is a point kernel code for gamma ray shielding calculations that is

D. K. Parsons; D. W. Nigg; W. Y. Yoon

1987-01-01

357

Electromagnetic Shielding Effectiveness of Steel Sheets with Partly Welded Seams  

Microsoft Academic Search

The effect of single welding flaws on the electromagnetic (EM) effectiveness of welded steel enclosures has been assessed. The possibility of resonant reradiation by these flaws has been examined, using resonance calculations and direct EM measurements. Using these results, a method was developed for assessing shielding quality of hardened military structures, such as SAFEGUARD sites, and EM shielded enclosures. The

Eenest Honig

1977-01-01

358

Space nuclear reactor shields for manned and unmanned applications  

SciTech Connect

Missions which use nuclear reactor power systems require radiation shielding of payload and/or crew areas to predetermined dose rates. Since shielding can become a significant fraction of the total mass of the system, it is of interest to show the effect of various parameters on shield thickness and mass for manned and unmanned applications. Algorithms were developed to give the thicknesses needed if reactor thermal power, separation distances, and dose rates are given as input. The thickness algorithms were combined with models for four different shield geometries to allow tradeoff studies of shield volume and mass for a variety of manned and unmanned missions. Shield design tradeoffs presented in this study include the effects of: Higher allowable dose rates; radiation hardened electronics; shorter crew exposure times; shield geometry; distance of the payload and/or crew from the reactor; and changes in the size of the shielded area. Specific NASA missions that were considered in this study include unmanned outer planetary exploration, manned advanced/evolutionary space station, and advanced manned lunar base.

McKissock, B.I.; Bloomfield, H.S.

1994-09-01

359

Shape, rheology and emplacement times of small martian shield volcanoes  

Microsoft Academic Search

This paper focuses on the shape of 31 shield volcanoes of small to intermediate size (a few tens of kilometers in diameter) in 5 regions of Mars: Tempe Terra, Syria Planum, Pavonis Mons, Arsia Mons and central Elysium Planitia. A model for the shape of these shield volcanoes is applied, based upon the concept of porous flow of an unconfined

D. Baratoux; P. Pinet; M. J. Toplis; N. Mangold; R. Greeley; A. R. Baptista

2009-01-01

360

Topography of the shield volcano, Olympus Mons on Mars  

Microsoft Academic Search

Olympus Mons, one of the largest known shield volcanoes in the solar system, covers an area of more than 3.2 x 10 to the 5th sq km and has a diameter of more than 600 km, excluding its vast aureole deposits. The structure is five times larger than the largest shield volcano on the earth. It is situated on the

S. S. C. Wu; P. A. Garcia; R. Jordan; F. J. Schafer; B. A. Skiff

1984-01-01

361

Radiation shielding for 250 MeV protons  

SciTech Connect

This paper is targetted at personnel who have the responsibility of designing the radiation shielding against neutron fluences created when protons interact with matter. Shielding of walls and roofs are discussed, as well as neutron dose leakage through labyrinths. Experimental data on neutron flux attenuation are considered, as well as some calculations using the intranuclear cascade calculations and parameterizations.

Awschalom, M.

1987-04-01

362

Face stability conditions with earth-pressure-balanced shields  

Microsoft Academic Search

Earth pressure balanced shields provide continuous support to the tunnel face using the freshly-excavated wet soil, which under pressure completely fills up the work chamber. EPB-shield tunnelling has been successfully applied worldwide in recent years. Under extremely unfavourable geological and hydrogeological conditions, however, face instabilities may occur. In this paper, the mechanism of face failure is analysed under drained conditions.

G. Anagnostou; K. Kovári

1996-01-01

363

An update on the middle levels problem Ian Shields  

E-print Network

An update on the middle levels problem Ian Shields IBM, P.O. Box 12195, Research Triangle Park, North Carolina 27709, USA Brendan J. Shields Department of Physics, Massachusetts Institute The middle levels problem is to find a Hamilton cycle in the middle levels, M2k+1, of the Hasse diagram of B2

Savage, Carla D.

364

BIOLOGIC SHIELDING AGAINST GAMMA-RAYS FROM FISSION-PRODUCTS  

Microsoft Academic Search

An effective attenuation-coefficient is determined in order to calcuiate ; the biologic shielding against gamma-rays of an originai fission product mixture. ; Its demonstration by diagrams is given as a function of the irradiation time of ; the uranium, of the cooling time after irradiation, of the wall thickness, and of ; the shielding material. (auth);

1962-01-01

365

An Efficient Algorithm for Shielding Electromagnetic Topological Diagram  

Microsoft Academic Search

An electromagnetic topology method used to analyze interactions between electronic systems and electromagnetic environment is presented. Combining electromagnetic topology model with the graph theory, an efficient algorithm is obtained. The algorithm can find out all the paths which have a lower shielding coefficient than the given threshold K in the shielding electromagnetic topological diagram.

Yongfeng Wang; Chengda Yu; Chaowei Zhang

2010-01-01

366

Performance study of galactic cosmic ray shield materials  

NASA Technical Reports Server (NTRS)

The space program is faced with two difficult radiation protection issues for future long-term operations. First, retrofit of shield material or conservatism in shield design is prohibitively expensive and often impossible. Second, shielding from the cosmic heavy ions is faced with limited knowledge on the physical properties and biological responses of these radiations. The current status of space shielding technology and its impact on radiation health is discussed herein in terms of conventional protection practice and a test biological response model. The impact of biological response on the selection of optimum materials for cosmic ray shielding is presented in terms of the transmission characteristics of the shield material. Although the systematics of nuclear cross sections are able to demonstrate the relation of exposure risk to shield-material composition, the current uncertainty in-nuclear cross sections will not allow an accurate evaluation of risk reduction. This paper presents a theoretical study of risk-related factors and a pilot experiment to study the effectiveness of choice of shield materials to reduce the risk in space operations.

Kim, Myung-Hee Y.; Wilson, John W.; Thibeault, Sheila A.; Nealy, John E.; Badavi, Francis F.; Kiefer, Richard L.

1994-01-01

367

Electromagnetic shielding of plastic material in laser diode modules  

Microsoft Academic Search

Electromagnetic shielding of plastic materials in laser modules was studied experimentally and theoretically. The conductive carbon fiber fillers into plastics to produce electrically conductive composites were proposed for the evaluation of electromagnetic interference (EMI) shielding effectiveness (SE). The different volume fractions of conductive carbon fiber fillers ranging from 5, 10, 20, and 30% were used. The SE of conductive plastics

S. K. Chiu; J. Y. Cheng; W. S. Jou; G. J. Jong; S. C. Wang; C. M. Wang; C. S. Lin; T. L. Wu; W. H. Cheng

2001-01-01

368

Computer program optimizes design of nuclear radiation shields  

NASA Technical Reports Server (NTRS)

Computer program, OPEX 2, determines minimum weight, volume, or cost for shields. Program incorporates improved coding, simplified data input, spherical geometry, and an expanded output. Method is capable of altering dose-thickness relationship when a shield layer has been removed.

Lahti, G. P.

1971-01-01

369

Shielding effects of concrete and foam external pipeline coatings  

Microsoft Academic Search

The research project began in July, 1986 and was completed in December, 1990. The objectives of the research were: To determine whether concrete and urethane foam-barrier coatings shield the pipe from cathodic-protection current, To determine whether the barrier coatings also effectively shield the pipe from the environment, thus reducing the need for cathodic protection, To determine what levels of cathodic

T. J. Barlo; D. P. Werner

1992-01-01

370

New Orleans Sees School Building Boom  

ERIC Educational Resources Information Center

Efforts to reinvent public education in New Orleans after Hurricane Katrina have drawn such interest that it's easy to lose sight of some very concrete changes that will become obvious over time: A generation of brand-new school buildings is rising across the city. New Orleans is in the early stages of a construction spree both to build and…

Robelen, Erik W.

2010-01-01

371

Fan-fold shielded electrical leads  

DOEpatents

Disclosed are fan-folded electrical leads made from copper cladded Kapton, for example, with the copper cladding on one side serving as a ground plane and the copper cladding on the other side being etched to form the leads. The Kapton is fan folded with the leads located at the bottom of the fan-folds. Electrical connections are made by partially opening the folds of the fan and soldering, for example, the connections directly to the ground plane and/or the lead. The fan folded arrangement produces a number of advantages, such as electrically shielding the leads from the environment, is totally non-magnetic, and has a very low thermal conductivity, while being easy to fabricate. 3 figs.

Rohatgi, R.R.; Cowan, T.E.

1996-06-11

372

Fan-fold shielded electrical leads  

DOEpatents

Fan-folded electrical leads made from copper cladded Kapton, for example, with the copper cladding on one side serving as a ground plane and the copper cladding on the other side being etched to form the leads. The Kapton is fan folded with the leads located at the bottom of the fan-folds. Electrical connections are made by partially opening the folds of the fan and soldering, for example, the connections directly to the ground plane and/or the lead. The fan folded arrangement produces a number of advantages, such as electrically shielding the leads from the environment, is totally non-magnetic, and has a very low thermal conductivity, while being easy to fabricate.

Rohatgi, Rajeev R. (Mountain View, CA); Cowan, Thomas E. (Livermore, CA)

1996-01-01

373

Superconducting magnetic shielding apparatus and method  

DOEpatents

Disclosed is a method and apparatus for providing magnetic shielding around a working volume. The apparatus includes a hollow elongated superconducting shell or cylinder having an elongated low magnetic pinning central portion, and two high magnetic pinning end regions. Transition portions of varying magnetic pinning properties are interposed between the central and end portions. The apparatus further includes a solenoid substantially coextensive with and overlying the superconducting cylinder, so as to be magnetically coupled therewith. The method includes the steps passing a longitudinally directed current through the superconducting cylinder so as to depin magnetic reservoirs trapped in the cylinder. Next, a circumferentially directed current is passed through the cylinder, while a longitudinally directed current is maintained. Depinned magnetic reservoirs are moved to the end portions of the cylinder, where they are trapped.

Clem, John R. (Ames, IA); Clem, John R. (Ames, IA)

1983-01-01

374

High purity silica reflecting heat shield development  

NASA Technical Reports Server (NTRS)

A reflecting heat shield composed of fused silica in which the scattering results from the refractive index mismatch between silica particles and the voids introduced during the fabrication process is developed. Major considerations and conclusions of the development are: the best material to use is Type A, which is capable of ultra-high-purity and which does not show the 0.243 micrometer absorption band; the reflection efficiency of fused silica is decreased at higher temperatures due to the bathochromic shift of the ultraviolet cut-off; for a given silica material, over the wavelength region and particle sizes tested, the monodisperse particle size configurations produce higher reflectances than continuous particle size configurations; and the smaller monodisperse particle size configurations give higher reflectance than the larger ones. A reflecting silica configuration that is an efficient reflector of shock layer radiation at high ablation temperatures is achieved by tailoring the matrix for optimum scattering and using an ultra-high-purity material.

Congdon, W.

1974-01-01

375

Radiation field characterization and shielding studies  

NASA Astrophysics Data System (ADS)

The ELI-Beamlines facility in the Czech Republic will offer to users versatile radiation sources in an unprecedented energy range. Laser-driven proton beams are expected to range between 50 MeV and 3 GeV. The number of particles delivered per laser shot is estimated to be 1010-1012. Starting from analytical calculations, as well as from dedicated simulations, the main proton fields produced in the laser-matter interaction have been described and used to characterize the "source terms" in full simulations with the Monte Carlo code FLUKA in order to assess a proper shielding. We present the results of this study and the proposed solutions together with a cross-check analysis performed with the Monte Carlo code GEANT4.

Ferrari, A.; Amato, E.; Margarone, D.

2013-07-01

376

Superconducting magnetic shielding apparatus and method  

DOEpatents

Disclosed are a method and apparatus for providing magnetic shielding around a working volume. The apparatus includes a hollow elongated superconducting shell or cylinder having an elongated low magnetic pinning central portion, and two high magnetic pinning end regions. Transition portions of varying magnetic pinning properties are interposed between the central and end portions. The apparatus further includes a solenoid substantially coextensive with and overlying the superconducting cylinder, so as to be magnetically coupled therewith. The method includes the steps passing a longitudinally directed current through the superconducting cylinder so as to depin magnetic reservoirs trapped in the cylinder. Next, a circumferentially directed current is passed through the cylinder, while a longitudinally directed current is maintained. Depinned magnetic reservoirs are moved to the end portions of the cylinder, where they are trapped. 5 figs.

Clem, J.R.; Clem, J.R.

1983-10-11

377

Superconducting magnetic shielding apparatus and method  

DOEpatents

Disclosed is a method and apparatus for providing magnetic shielding around a working volume. The apparatus includes a hollow elongated superconducting shell or cylinder having an elongated low magnetic pinning central portion, and two high magnetic pinning end regions. Transition portions of varying magnetic pinning properties are interposed between the central and end portions. The apparatus further includes a solenoid substantially coextensive with and overlying the superconducting cylinder, so as to be magnetically coupled therewith. The method includes the steps passing a longitudinally directed current through the superconducting cylinder so as to depin magnetic reservoirs trapped in the cylinder. Next, a circumferentially directed current is passed through the cylinder, while a longitudinally directed current is maintained. Depinned magnetic reservoirs are moved to the end portions of the cylinder, where they are trapped.

Clem, J.R.

1982-07-09

378

Mariner 9 views of shield volcano  

NASA Technical Reports Server (NTRS)

A Martian shield volcano, approximately 25 miles across at the crater, photographed consecutively by Mariner 9 with the wide-angle and telephoto lenses. The summit crater and groves down the flank probably were produced by subsidence flowing subsurface movement of magma.

Mariner 9 was the first spacecraft to orbit another planet. The spacecraft was designed to continue the atmospheric studies begun by Mariners 6 and 7, and to map over 70% of the Martian surface from the lowest altitude (1500 kilometers [900 miles])and at the highest resolutions (1 kilometer per pixel to 100 meters per pixel) of any previous Mars mission

Mariner 9 was launched on May 30, 1971 and arrived on November 14, 1971.

1972-01-01

379

SUBURFACE SHIELDING-SPECIFIC SOURCE TERM EVALUATION  

SciTech Connect

The purpose of this work is to provide supporting calculations for determination of the radiation source terms specific to subsurface shielding design and analysis. These calculations are not intended to provide the absolute values of the source terms, which are under the charter of the Waste Package Operations (WPO) Group. Rather, the calculations focus on evaluation of the various combinations of fuel enrichment, burnup and cooling time for a given decay heat output, consistent with the waste package (WP) thermal design basis. The objective is to determine the worst-case combination of the fuel characteristics (enrichment, burnup and cooling time) which would give the maximum radiation fields for subsurface shielding considerations. The calculations are limited to PWR fuel only, since the WP design is currently evolving with thinner walls and a reduced heat load as compared to the viability assessment (VA) reference design. The results for PWR fuel will provide a comparable indication of the trend for BWR fuel, as their characteristics are similar. The source term development for defense high-level waste and other spent nuclear fuel (SNF) is the responsibility of the WPO Group, and therefore, is not included this work. This work includes the following items responsive to the stated purpose and objective: (1) Determine the possible fuel parameters (initial enrichment, burnup and cooling time), that give the same decay heat value as specified for the waste package thermal design; (2) Obtain the neutron and gamma source terms for the various combinations of the fuel parameters for use in radiation field calculations; and (3) Calculate radiation fields on the surfaces of the waste package and its transporter to quantify the effects of the fuel parameters with the same decay heat value for use in identifying the worst-case combination of the fuel parameters.

S. Su

1999-08-24

380

Shielded radiation protection quantities beyond LEO  

NASA Astrophysics Data System (ADS)

The National Council on Radiation Protection and Measurements (NCRP) has recommended that the quantities used to evaluate health risk to astronauts due to radiation exposure be effective dose and gray-equivalent. The NCRP recommends that effective dose be the limiting quantity for prevention of stochastic effects. Effective dose is a measure of whole body exposure, a weighted average of dose equivalent to a number body tissues for which the NCRP has adopted tissue weighting factors recommended by the International Commission on Radiation Protection (ICRP). For deterministic effects, the NCRP has recommended that gray-equivalent be used. Gray-equivalent is evaluated for specific critical organs and is the weighted sum of absorbed dose from field components to that organ using the relative biological effectiveness (RBE) number for that field component. RBE numbers recommended by the NCRP are used. The NCRP has provided effective dose limits as well as limits for gray-equivalent to eyes, skin, and blood forming organs (BFO) for astronauts in low earth orbit (LEO). As yet, no such limits have been defined for astronaut operations beyond LEO. In this study, the radiation protection quantities, effective dose and gray-equivalent to the eyes, skin, and BFO, are calculated for several environments beyond LEO. The lunar surface and Martian environments are included. For each environment, these radiation protection quantities are calculated behind varying amounts of various types of shielding materials. The results are compared to the exposure limits for LEO, since limits have not yet been defined for interplanetary missions. The benefits of using shielding material containing hydrogen and choosing optimal mission times are discussed.

Clowdsley, M. S.; Wilson, J. W.; Kim, M. Y.; Anderson, B. M.; Nealy, J. E.

381

Galactic and Solar Cosmic Ray Shielding in Deep Space  

NASA Technical Reports Server (NTRS)

An analysis of the radiation hazards in support of NASA deep space exploration activities is presented. The emphasis is on materials required for radiation protection shielding. Aluminum has been found to be a poor shield material when dose equivalent is used with exposure limits for low Earth orbit (LEO) as a guide for shield requirements. Because the radiation issues are cost related-the parasitic shield mass has high launch costs, the use of aluminum as a basic construction material is clearly not cost-effective and alternate materials need to be developed. In this context, polyethylene is examined as a potentially useful material and demonstrates important advantages as an alternative to aluminum construction. Although polyethylene is useful as a shield material, it may not meet other design criteria (strength, stability, thermal); other polymer materials must be examined.

Wilson, John W.; Cucinotta, Francis A.; Tai, H.; Simonsen, Lisa C.; Shinn, Judy L.; Thibeault, Shelia; Kim, M. Y.

1997-01-01

382

Effect of an overhead shield on gamma-ray skyshine  

SciTech Connect

A hybrid Monte Carlo and integral line-beam method is used to determine the effect of a horizontal slab shield above a gamma-ray source on the resulting skyshine doses. A simplified Monte Carlo procedure is used to determine the energy and angular distribution of photons escaping the source shield into the atmosphere. The escaping photons are then treated as a bare, point, skyshine source, and the integral line-beam method is used to estimate the skyshine dose at various distances from the source. From results for arbitrarily collimated and shielded sources, the skyshine dose is found to depend primarily on the mean-free-path thickness of the shield and only very weakly on the shield material.

Stedry, M.H.; Shultis, J.K.; Faw, R.E. [Kansas State Univ., Manhattan, KS (United States). Dept. of Nuclear Engineering

1996-06-01

383

A proposed performance index for galactic cosmic ray shielding materials  

NASA Astrophysics Data System (ADS)

In past studies, the reductions in absorbed dose and dose equivalent due to choice of material composition have been used to indicate shield effectiveness against exposure to galactic cosmic rays. However, these quantities are highly inaccurate in assessing shield effectiveness for protection against the biological effects of long-term exposure to the galactic heavy ions. A new quantity for shield performance is defined that correlates well with cell killing and cell transformation behind various shield thicknesses and materials. In addition, a relative performance index is identified that is inversely related to biological injury for different materials at a fixed shield mass and is directly related to the ratio of the fourth- and the second-order linear energy transfer (LET) moments.

Wilson, John W.; Wood, J. S.; Shinn, Judy L.; Cucinotta, Francis A.; Nealy, John E.

1993-08-01

384

MCG measurement in the environment of active magnetic shield.  

PubMed

MCG (Magnetocardiography) measurement by a SQUID gradiometer was attempted with only active magnetic shielding (active shielding). A three-axis-canceling-coil active shielding system, where three 16-10-16 turns-coil sets were put in the orthogonal directions, produces a homogeneous magnetic field in a considerable volume surrounding the center. Fluxgate sensors were used as the reference sensors of the system. The system can reduce environmental magnetic noise at low frequencies of less than a few Hz, at 50 Hz and at 150 Hz. Reducing such disturbances stabilizes biomagnetic measurement conditions for SQUIDs in the absence of magnetically shielded rooms (MSR). After filtering and averaging the measured MCG data by a first-order SQUID gradiometer with only the active shielding during the daytime, the QRS complex and T wave was clearly presented. PMID:16012640

Yamazaki, K; Kato, K; Kobayashi, K; Igarashi, A; Sato, T; Haga, A; Kasai, N

2004-01-01

385

Carpet cloak with photonic crystal shield that permits information exchange  

NASA Astrophysics Data System (ADS)

Carpet cloaks designed by optical transformation usually include a perfect shield, which exclude the electromagnetic fields from the under cloaked region. Due to the shield, observers in the cloaked area cannot “see” the outside. In this article, we report a flat carpet cloak that permits information exchange with outer environment by using one- or two-dimensional photonic crystal structures as substitutes for the perfect shield. The lateral shifts at the reflecting surface of the effective shields, which make the carpet cloak detectable, are considered and calculated with a Gaussian beam illumination. In order to counteract the lateral shifts, we redesign the parameters of the cloaking slab based on the coordinate transformation. Good agreements have been obtained between the adjusted carpet and ideal carpet with a perfect shield.

Xu, Yan; Wang, Shenyun; Wen, Geyi

2014-10-01

386

ETR BUILDING, TRA642, INTERIOR. BASEMENT. CAMERA FACES SOUTH AND LOOKS ...  

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

ETR BUILDING, TRA-642, INTERIOR. BASEMENT. CAMERA FACES SOUTH AND LOOKS AT DOOR TO M-3 CUBICLE. CUBICLE WALLS ARE MADE OF LEAD SHIELDING BRICKS. VALVE HANDLES AND STEMS PERTAIN TO SAMPLING. METAL SHIELDING DOOR. NOTE GLOVE BOX TO RIGHT OF CUBICLE DOOR. INL NEGATIVE NO. HD-46-21-3. Mike Crane, Photographer, 2/2005 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

387

11. BUILDING NO. 620B. INTERIOR VIEW LOOKING NORTH, SHOWING PENDULUM ...  

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

11. BUILDING NO. 620-B. INTERIOR VIEW LOOKING NORTH, SHOWING PENDULUM AND FRAME IN FOREGROUND, SHIELD FOR OPERATORS IN BACKGROUND. FRICTION TEST IS OBSERVED FROM BEHIND BLAST SHIELD BY A SERIES OF MIRRORS. ANVIL IN CENTER OF PENDULUM FRAME HOLDS EXPLOSIVE WHOSE SENSITIVITY TO FRICTION IS TO BE TESTED. PANS ON EITHER SIDE CATCH ANY UNBURNT EXPLOSIVE SLUNG FROM ANVIL DURING TEST TO PREVENT EXPLOSIVE HAZARD. - Picatinny Arsenal, 600 Area, Test Areas District, State Route 15 near I-80, Dover, Morris County, NJ

388

78 FR 26090 - Content Specifications and Shielding Evaluations for Type B Transportation Packages  

Federal Register 2010, 2011, 2012, 2013

...REGULATORY COMMISSION [NRC-2012-0270] Content Specifications and Shielding Evaluations...Issue Summary (RIS) 2013-04, ``Content Specifications and Shielding Evaluations...Radioactive Material,'' for the review of content specifications and shielding...

2013-05-03

389

77 FR 67678 - Content Specifications and Shielding Evaluations for Type B Transportation Packages  

Federal Register 2010, 2011, 2012, 2013

...REGULATORY COMMISSION [NRC-2012-0270] Content Specifications and Shielding Evaluations...Issue Summary (RIS) 2012-XX, ``Content Specifications and Shielding Evaluations...Radioactive Material,'' for the review of content specifications and shielding...

2012-11-13

390

76 FR 70761 - Weather Shield Manufacturing, Inc. Corporate Office, Medford, WI; Notice of Negative...  

Federal Register 2010, 2011, 2012, 2013

...Training Administration [TA-W-72,673] Weather Shield Manufacturing, Inc. Corporate...administrative record in Former Employees of Weather Shield Manufacturing, Inc. v. United...applicable to workers and former workers of Weather Shield Manufacturing, Inc.,...

2011-11-15

391

75 FR 57519 - Weather Shield Manufacturing, Medford, WI; Notice of Negative Determination Regarding Application...  

Federal Register 2010, 2011, 2012, 2013

...Training Administration [TA-W-72,673] Weather Shield Manufacturing, Medford, WI...applicable to workers and former workers of Weather Shield Manufacturing, Inc., Medford...production of doors and windows at various Weather Shield Manufacturing, Inc....

2010-09-21

392

76 FR 35026 - Weather Shield Manufacturing, Inc. Corporate Office, Medford, WI; Notice of Amended Negative...  

Federal Register 2010, 2011, 2012, 2013

...Training Administration TA-W-72,673 Weather Shield Manufacturing, Inc. Corporate...administrative record in Former Employees of Weather Shield Manufacturing, Inc. v. United...applicable to workers and former workers of Weather Shield Manufacturing, Inc.,...

2011-06-15

393

75 FR 51851 - Weather Shield Manufacturing, Inc., Corporate Office, Medford, WI; Notice of Revised...  

Federal Register 2010, 2011, 2012, 2013

...Training Administration [TA-W-64,725] Weather Shield Manufacturing, Inc., Corporate...for further review, Former Employees of Weather Shield Manufacturing, Inc. v. United...December 17, 2008, former workers of Weather Shield Manufacturing, Inc....

2010-08-23

394

Building Design  

NSDL National Science Digital Library

The Building Design site bills itself as "the architects" website", and it is a claim that is quite accurate and apropos. Designed to complement their print publication, the site is a treasure-trove of material for just about anyone who is involved in any aspect of building, including architects, design theorists, planners, and so on. As the magazine is based in the United Kingdom, there's definitely a British Isles focus. Readers probably won't mind as the site offers excellent coverage of the field in the "News" section, where they can sign up to receive email updates, watch some slideshows of new and proposed buildings, and read long-form pieces. Not surprisingly, the site is keeping up with the proverbial Joneses" by offering a smattering of intelligent and lively blogs, coupled with podcasts that mix contemporary interviews and discussions with archived materials such as talks with Buckminster Fuller on his environmental philosophy.

395

Cervical Cancer Stage IIIB  

MedlinePLUS

... Cancer Stage IIIB Description: Stage IIIB cervical cancer; drawing shows cancer in the cervix, the vagina, and ... that connect the kidneys to the bladder). The drawing shows the ureter on the right blocked by ...

396

Lunar Module Ascent Stage  

NASA Technical Reports Server (NTRS)

The Lunar Module 'Spider' ascent stage is photographed from the Command/Service Module on the fifth day of the Apollo 9 earth-orbital mission. The Lunar Module's descent stage had already been jettisoned.

1969-01-01

397

Bootstrap Classification and Point-Based Feature Selection from Age-Staged Mouse Cerebellum Tissues of Matrix Assisted Laser Desorption/Ionization Mass Spectra using a Fuzzy Rule-Building Expert System  

PubMed Central

A bootstrap method for point-based detection of candidate biomarker peaks has been developed from pattern classifiers. Point-based detection methods are advantageous in comparison to peak-based methods. Peak determination and selection is problematic when spectral peaks are not baseline resolved or on a varying baseline. The benefit of point-based detection is that peaks can be globally determined from the characteristic features of the entire data set (i.e., subsets of candidate points) as opposed to the traditional method of selecting peaks from individual spectra and then combining the peak list into a data set. The point-based method is demonstrated to be more effective and efficient using a synthetic data set when compared to using Mahalanobis distance for feature selection. In addition, probabilities that characterize the uniqueness of the peaks are determined. This method was applied for detecting peaks that characterize age-specific patterns of protein expression of developing and adult mouse cerebella from matrix assisted laser desorption/ionization (MALDI) mass spectrometry (MS) data. The mice comprised three age groups; 42 adults, 19 14-day old pups, and 16 7-day old pups. Three sequential spectra were obtained from each tissue section to yield 126, 57 and 48 spectra for adult, 14-day old pup, and 7-day old pup spectra, respectively. Each spectrum comprised 71,879 mass measurements in a range of 3.5-50 kDa. A previous study revealed that 846 unique peaks were detected that were consistent for 50% of the mice in each age group1. A fuzzy rule-building expert system (FuRES) was applied to investigate the correlation of age with features in the MS data. FuRES detected two outlier pup-14 spectra. Prediction was evaluated using 100 bootstrap samples of 2 Latin-partitions (i.e., 50:50 split between training and prediction set) of the mice. The spectra without the outliers yielded classification rates of 99.1±0.1%, 90.1±0.8%, and 97.0±0.6% for adults, 14-day old pups, and 7-day old pups, respectively. At a 95% level of significance, 100 bootstrap samples disclosed 35 adult and 21 pup distinguishing peaks for separating adults from pups; and 8 14-day old and 15 7-day old predictive peaks for separating 14-day old pup from 7-day old pup spectra. A compressed matrix comprising 40,393 points that were outside the 95% confidence intervals of one of the two FuRES discriminants was evaluated and the classification improved significantly for all classes. When peaks that satisfied a quality criterion were integrated, the 55 integrated peak areas furnished significantly improved classification for all classes: the selected peak areas furnished classification rates of 100%, 97.3±0.6%, and 97.4±0.3% for adult, 14-day old pups, and 7-day old pups using 100 bootstrap Latin partitions evaluations with the predictions averaged. When the bootstrap size was increased to 1000 samples, the results were not significantly affected. The FuRES predictions were consistent with those obtained by discriminant partial least squares (DPLS) classifications. PMID:17870284

Harrington, Peter B.; Laurent, Claudine; Levinson, Douglas F.; Levitt, Pat; Markey, Sanford P.

2007-01-01

398

Building Tall  

NSDL National Science Digital Library

In this engineering activity (page 2 of PDF), young learners investigate how a wide base can make a building more stable. Learners use blocks or boxes of different sizes to construct stable towers. Learners will compare and contrast different structures, document their observations, experiment with different materials, and conduct stability tests. This activity is part of the Curious George "Under Construction" lesson plan and related to the show Curious George on PBS, specifically the episode "Curious George's Home for Pigeons." The lesson plan includes several activities that explore building engineering. Activities are connected to fiction and non-fiction books and include family extension projects.

Kids, Pbs

2006-01-01

399

Building Sinusoids  

ERIC Educational Resources Information Center

In this article, the author describes the development and implementation of a measurement-based group activity designed to support students in understanding the connection between angle magnitude and the shape of the sine function. She explains that the benefit of this activity is that it allows students to build their trigonometric knowledge…

Landers, Mara G.

2013-01-01

400

Building Trust.  

ERIC Educational Resources Information Center

Describes how an initial $1,500 grant helped build a desperately needed health clinic on the Pine Ridge Reservation. Provides the history of the clinic, from its beginning as a small grant to its ultimate development into a $400,000 solar-heated health clinic with a staff of 9 people, including a full-time physician. (MAB)

Ambler, Marjane

1994-01-01

401

Laboratory Buildings.  

ERIC Educational Resources Information Center

The need for flexibility in science research facilities is discussed, with emphasis on the effect of that need on the design of laboratories. The relationship of office space, bench space, and special equipment areas, and the location and distribution of piping and air conditioning, are considered particularly important. This building type study…

Barnett, Jonathan

402

Building Community.  

ERIC Educational Resources Information Center

The purpose of this eight-unit course is to explore the values and issues of modern urban neighborhoods. It focuses on how community leaders can apply the broad principle of justice to problems of security, reciprocity, and fellowship that face most neighborhoods today. The course is intended for use by community leaders in building community…

Schwartz, Edward

403

Building Trades.  

ERIC Educational Resources Information Center

This curriculum guide provides materials for a competency-based course in building trades at the secondary level. The curriculum design uses the curriculum infused model for the teaching of basic skills as part of vocational education and demonstrates the relationship of vocationally related skills to communication, mathematics, and science…

Gudzak, Raymond

404

2. PRINTING AND ADVERTISING BUILDING, ADMINISTRATION BUILDING, MERCHANDISE BUILDING, AND ...  

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

2. PRINTING AND ADVERTISING BUILDING, ADMINISTRATION BUILDING, MERCHANDISE BUILDING, AND GARDEN, VIEW TO SOUTHWEST - Sears Roebuck & Company Mail Order Plant, Bounded by Lexington & Grenshaw Streets, Kedzie Avenue & Independence Boulevard, Chicago, Cook County, IL

405

Checklist of the terrestrial vertebrates of the Guiana Shield  

USGS Publications Warehouse

Distributions are given for 1850 species of terrestrial vertebrates in the Guiana Shield region of northeastern South America, with introductory text by the authors of each section. Distributions cover the three Guianas (Guyana, Surinam, and French Guiana), and the states of the Venezuelan Guayna (Amazonas, Bolivar, and Delta Amacuro), and in some cases the states of the Brazilian portion of the Guiana Shield (Amazonas, Roraima, Para, and Amapa), and the Colombian portion of the Guiana Shield. The first section is a checklist of amphibians of the Guiana Shield, by J. Celsa Sefiaris and Ross MacCulloch, detailing the distribution of 269 species. The second section is a checklist of the reptiles of the Guiana Shield by Teresa C. S. de Avila Pires, detailing the distribution of 295 species. The third section is a checklist of the birds of the Guiana Shield, by Chris Milensky, Wiltshire Hinds, Alexandre Aleixo, and Maria de Fatima C. Lima, detailing the distribution of 1004 species. The fourth section is a checklist of the mammals of the Guiana Shield, by Burton K. Lim, Mark D. Engstrom, and Jose Ochoa G., detailing the distribution of 282 species.

2005-01-01

406

Thick Galactic Cosmic Radiation Shielding Using Atmospheric Data  

NASA Technical Reports Server (NTRS)

NASA is concerned with protecting astronauts from the effects of galactic cosmic radiation and has expended substantial effort in the development of computer models to predict the shielding obtained from various materials. However, these models were only developed for shields up to about 120 g!cm2 in thickness and have predicted that shields of this thickness are insufficient to provide adequate protection for extended deep space flights. Consequently, effort is underway to extend the range of these models to thicker shields and experimental data is required to help confirm the resulting code. In this paper empirically obtained effective dose measurements from aircraft flights in the atmosphere are used to obtain the radiation shielding function of the earth's atmosphere, a very thick shield. Obtaining this result required solving an inverse problem and the method for solving it is presented. The results are shown to be in agreement with current code in the ranges where they overlap. These results are then checked and used to predict the radiation dosage under thick shields such as planetary regolith and the atmosphere of Venus.

Youngquist, Robert C.; Nurge, Mark A.; Starr, Stanley O.; Koontz, Steven L.

2013-01-01

407

Dose buildup factor formula for double-layered shields  

SciTech Connect

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 shields have been developed in the past with various degrees of success and limitations. The GP formula is excellent but applies to single-layer materials only. In this work, gamma-ray dose buildup factors for double-layer shields have been computed using the MCNP code. A point monoenergetic isotropic source was used with energy from 0.5 to 6 MeV. The source was placed at the center of the first spherical materials, surrounded by a second one. Detectors were placed on the surface of the second material and used to tally the photon flux in a six-energy-group structure. The shielding materials considered were water, lead, steel, concrete, and some of their combinations for double-layered shields ranging in thickness from 1 to 10 mean free paths (mfp).

Guvendik, M.; Tsoulfanidis, N.

1999-07-01

408

Novel cryogen-free actively shielded superconducting magnets for maglev vehicles. Final report, August 1991-June 1992  

SciTech Connect

The report presents the results of a research effort into the design of a shielded superconducting magnet system for a maglev vehicle. The magnet design is based on a novel cryogen-free technology which allows operation without the use of any cryogenic fluids. This is accomplished by the use of a two-stage Gifford-McMahon (G-M) cryogenic refrigerator to provide cooling of the coil and a single cryostat thermal radiation shield by conduction. The design operating temperature of the magnet is 7.5 K, and that of the shield is 43 K. The magnet is wound with a tape form of niobium tin superconductor which allows operation at a module current density of 8100 A/sq cm at a flux density of 3.4 T at the 7.5 K temperature with a margin of 4.5 K to critical temperature. The magnet design is coupled with a linear synchronous motor and null-flux sidewall levitation system to provide a workable maglev system design. Costs for several components of the design, including coils and cryostat, shielding, and power conditioning apparatus are estimated.

Vermilyea, M.E.

1992-06-01

409

CHESS upgrade 1995: Improved radiation shielding  

SciTech Connect

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 {approx_gt}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. (Abstract Truncated)

Finkelstein, K. [CHESS, Cornell University, Ithaca, NY 14853 (United States)] [CHESS, Cornell University, Ithaca, NY 14853 (United States)

1996-09-01

410

Sutures and shear zones in the Arabian-Nubian Shield  

NASA Astrophysics Data System (ADS)

Deformational belts in the Arabian-Nubian Shield (ANS) are divided into: (1) those associated with sutures, both arc-arc and arc-continental; and (2) post-accretionary structures which include north trending shortening zones and northwest trending strike-slip faults. The arc-arc sutures manifest collision between arc terranes at -800-700 Ma. They are orientated east to northeast in the northern part of the ANS and north to north-northeast in the south. North or south verging ophiolitic nappes are associated with the east to northeast trending sutures. These nappes were steepened by upright folds associated with the final stages of collision between terranes. East or west verging ophiolitic nappes are associated with the north to north-northeast trending sutures. These were deformed by upright folds and strike-slip faults related to oblique collision between terranes and/or post-accretionary deformations. The arc-continental sutures define the eastern and western boundaries of the ANS and are marked by north trending deformational belts which accompanied collision of the ANS with east and west Gondwana at -750-650 Ma. The post-accretionary structures were developed between -650-550 Ma due to continued shortening of the ANS. This produced north trending shortening zones which offset the east to northeast trending sutures in the northern part of the ANS but were superimposed as co-axial deformation on the north to north-northeast trending sutures in the south. The shortening deformation culminated with the development of northwest trending strike-slip faults and shear zones.

Abdelsalam, M. G.; Stern, R. J.

1996-10-01

411

Inhibited Shaped Charge Launcher Testing of Spacecraft Shield Designs  

NASA Technical Reports Server (NTRS)

This report describes a test program in which several orbital debris shield designs were impact tested using the inhibited shaped charge launcher facility at Southwest Research Institute. This facility enables researchers to study the impact of one-gram aluminum projectiles on various shielding designs at velocities above 11 km/s. A total of twenty tests were conducted on targets provided by NASA-MSFC. This report discusses in detail the shield design, the projectile parameters and the test configuration used for each test. A brief discussion of the target damage is provided, as the detailed analysis of the target response will be done by NASA-MSFC.

Grosch, Donald J.

1996-01-01

412

Galactic heavy-ion shielding using electrostatic fields  

NASA Technical Reports Server (NTRS)

The shielding of spacecraft against galactic heavy ions, particularly high-energy Fe(56) nuclei, by electrostatic fields is analyzed for an arrangement of spherical concentric shells. Vacuum breakdown considerations are found to limit the minimum radii of the spheres to over 100 m. This limitation makes it impractical to use the fields for shielding small spacecraft. The voltages necessary to repel these Fe(56) nuclei exceed present electrostatic generating capabilities by over 2 orders of magnitude and render the concept useless as an alternative to traditional bulk-material shielding methods.

Townsend, L. W.

1984-01-01

413

Shielding Analyses for VISION Beam Line at SNS  

SciTech Connect

Full-scale neutron and gamma transport analyses were performed to design shielding around the VISION beam line, instrument shielding enclosure, beam stop, secondary shutter including a temporary beam stop for the still closed neighboring beam line to meet requirement is to achieve dose rates below 0.25 mrem/h at 30 cm from the shielding surface. The beam stop and the temporary beam stop analyses were performed with the discrete ordinate code DORT additionally to Monte Carlo analyses with the MCNPX code. Comparison of the results is presented.

Popova, Irina [ORNL] [ORNL; Gallmeier, Franz X [ORNL] [ORNL

2014-01-01

414

Study of shielding design for SANS at CSNS  

NASA Astrophysics Data System (ADS)

The small angle neutron scattering (SANS) instrument is presently being constructed at Chinese Spallation Neutron Source (CSNS) in China, and the biological shielding design is needed to prevent the instrument from causing excessive dose rates in accessible locations. In this paper, the study of shielding design for SANS that relies on Monte Carlo simulation is introduced. Beam line shielding calculations are performed considering both scenarios of closed versus open T0 chopper. The basic design scheme of the beam stop is discussed. The size of the T0 chopper rotor is also estimated.

Liang, Tai-Ran; Shen, Fei; Yin, Wen; Yu, Quan-Zhi; Yu, Chun-Xu; Tao, Ju-Zhou; Liang, Tian-Jiao

2014-07-01

415

Corrosion evaluation of stainless steel root weld shielding  

SciTech Connect

The effect of five shielding methods for gas tungsten arc root pass welds, on the corrosion resistance of stainless steel was evaluated in two laboratory solutions. The first experiment was performed in 6% ferric chloride solution, a test designed to corrode stainless steel. The second experiment was performed in a simulated paper machine white water solution that contained hydrogen peroxide. Argon shielding produced excellent results by maintaining corrosion resistance in both solutions. Nitrogen purging and flux coated TIG rod techniques produced variable results. Paste fluxes and welding without shielding are not recommended for root protection. They performed very poorly with the welds corroding in both tests.

Gorog, M.; Sawyer, L.A.

1999-07-01

416

Critical Shields Values in Coarse-Bedded Steep Streams  

NASA Astrophysics Data System (ADS)

Critical Shields values for poorly mobile, semi-alluvial mountain streams are not provided by the original Shields diagram and are still debated. This empirical study uses gravel bedload samples collected with unbiasing samplers at 22 stream sites and establishes a relation between instantaneous discharge and the largest sampled bedload particle size for each site. Using relations between flow depth and discharge, critical Shields values for particle sizes corresponding to the bed surface D50, D16, D84, and D50s sizes at each site can be backcomputed from the established critical flow or flow competence relations. Critical Shields values for all bed material particle size percentiles increase with stream gradient Sx and are stratifiable by relative flow depth d/D50 and relative roughness (D84/d) which improves prediction. Critical Shields values for the bed D16 sizes (?*c16) are approximately three times larger than those for the D50 size (?*c50), while those for the D84 size (?*c84) are approximately half of ?*c50. It remains unclear to what extent physical processes or numerical artifacts contribute to determining critical Shields values. Specific critical Shields values are needed to predict the average largest particle size mobile at bankfull flow (DBmax,bf). So far, no Shields values are available for this common task, especially not in poorly mobile semi-alluvial streams. Critical bankfull Shields values (?*cbf) backcomputed from the largest particles transported at bankfull flow approach ?*c16 at steep gradient streams and ?*c84 at low gradients and therefore increase very steeply with Sx. The relation ?*cbf = f(Sx) is stratified by bed mobility D50/DBmax,bf and predictable if bed mobility can be categorized in the field. Non-critical Shields values (?*bf50) computed from bankfull flow depth and the bed surface D50 size differ from ?*c50 and from critical bankfull Shields values ?*cbf. Only in bankfull mobile streams where D50/DBmax,bf = 1 can ?*cbf, ?*c50, and ?*bf50 be used interchangeably. In highly mobile streams, substituting ?*cbf by ?*bf50 overpredicts the DBmax,bf size by up to fivefold and underpredicts DBmax,bf by the same amount in poorly mobile streams. A value of 0.03 is appropriate for ?*cbf only on highly mobile beds with Sx ? 0.01, but overpredicts DBmax,bf by 30-fold on poorly mobile beds with Sx ? 0.1. Differences in field and computational methods also affect critical Shields values.

Bunte, K.; Abt, S. R.; Swingle, K. W.; Cenderelli, D. A.; Schneider, J. M.

2013-12-01

417

Impact of the retained heat shield concept on science instruments  

NASA Technical Reports Server (NTRS)

Associated interface problems between the mass spectrometer and the actual probe design are considered along with the problem of producing a clean sample to the gas detection instrument. Of particular interest is the penetration of the heat shield by the mass spectrometer sampling tube, because it must be demonstrated that the sampling tube can penetrate the heat shield and that the mass spectrometer can be supplied with a contaminant-free gas sample, free of contaminants from out-gassing of the heat shield.

Kessler, W. C.

1974-01-01

418

New Neutron Shielding in the Edelweiss-III Experiment  

NASA Astrophysics Data System (ADS)

In dark matter WIMP searches the fundamental background is due to neutron flux. Thus shielding plays a crucial role in attenuating this flux and consequently in suppressing nuclear recoil background events. The transition from EDELWEISS-II to EDELWEISS-III with a total fiducial mass of 24 kg and improved background rejection has required the modification of the neutron shielding. In this paper we describe the design of this new neutron shielding and give an estimate of the expected neutron rate in comparison with the EDELWEISS-II experiment.

Navick, X.-F.

2014-09-01

419

Building Specifications  

NASA Technical Reports Server (NTRS)

The building in the top photo is the new home of the National Permanent Savings Bank in Washington, D.C., designed by Hartman-Cox Architects. Its construction was based on a money-saving method of preparing building specifications which derived from NASA technology developed to obtain quality construction while holding down cost of launch facilities, test centers and other structures. Written technical specifications spell out materials and components to be used on construction projects and identify the quality tests each item must pass. Specifications can have major impact on construction costs. Poorly formulated specifications can lead to unacceptable construction which must be replaced, unnecessarily high materials costs, safety hazards, disputes and often additional costs due to delays and litigation. NASA's Langley Research Center developed a novel approach to providing accurate, uniform, cost-effective specifications which can be readily updated to incorporate new building technologies. Called SPECSINTACT, it is a computerized - system accessible to all NASA centers involved in construction programs. The system contains a comprehensive catalog of master specifications applicable to many types of construction. It enables designers of any structure to call out relevant sections from computer storage and modify them to fit the needs of the project at hand. Architects and engineers can save time by concentrating their efforts on needed modifications rather than developing all specifications from scratch. Successful use of SPECSINTACT has led to a number of spinoff systems. One of the first was MASTERSPEC, developed from NASA's experience by Production Systems for Architects and Engineers, Inc., an organization established by the American Institute of Architects. MASTERSPEC, used in construction of the bank building pictured, follows the same basic format as SPECSINTACT and can be used in either automated or manual modes. The striking appearance of the bank building shows that, while MASTERSPEC saves time and money, its use involves no sacrfice in architectural design freedom. The Naval Engineering Facilities Command employs an automated specifications system based on SPECSINTACT. The Public Buildings Service of the General Services Administration used SPECSINTACT as a starting point in a plan to make its guideline specifications available to architects and engineers on a nationwide computer network. Public Technology, Inc., a NASA Technology Application Team, is working with Production Systems for Architects and Engineers, Inc., to promote widespread use of the system by state and local governments for cost benefits to taxpayers.

1978-01-01

420

Building Buildings with Triangular Numbers  

ERIC Educational Resources Information Center

Triangular numbers are used to unravel a new sequence of natural numbers here-to-fore not appearing on the Encyclopedia of Integer Sequences website. Insight is provided on the construction of the sequence using "buildings" as a viewable model of the sequence entries. A step-by-step analysis of the sequence pattern reveals a method for generating…

Pagni, David L.

2006-01-01

421

Two stage catalytic combustor  

NASA Technical Reports Server (NTRS)

A catalytic combustor (14) includes a first catalytic stage (30), a second catalytic stage (40), and an oxidation completion stage (49). The first catalytic stage receives an oxidizer (e.g., 20) and a fuel (26) and discharges a partially oxidized fuel/oxidizer mixture (36). The second catalytic stage receives the partially oxidized fuel/oxidizer mixture and further oxidizes the mixture. The second catalytic stage may include a passageway (47) for conducting a bypass portion (46) of the mixture past a catalyst (e.g., 41) disposed therein. The second catalytic stage may have an outlet temperature elevated sufficiently to complete oxidation of the mixture without using a separate ignition source. The oxidation completion stage is disposed downstream of the second catalytic stage and may recombine the bypass portion with a catalyst exposed portion (48) of the mixture and complete oxidation of the mixture. The second catalytic stage may also include a reticulated foam support (50), a honeycomb support, a tube support or a plate support.

Alvin, Mary Anne (Inventor); Bachovchin, Dennis (Inventor); Smeltzer, Eugene E. (Inventor); Lippert, Thomas E. (Inventor); Bruck, Gerald J. (Inventor)

2010-01-01

422

Evolution of large shield volcanoes on Venus  

NASA Technical Reports Server (NTRS)

We studied the geologic history, topographic expression, and gravity signature of 29 large Venusian shield volcanoes with similar morphologies in Magellan synthetic aperture radar imagery. While they appear similar in imagery, 16 have a domical topographic expression and 13 have a central depression. Typical dimensions for the central depression are 150 km wide and 500 m deep. The central depressions are probably not calderas resulting from collapse of a shallow magma chamber but instead are the result of a corona-like sagging of a previously domical volcano. The depressions all have some later volcanic filling. All but one of the central depression volcanoes have been post-dated by geologic features unrelated to the volcano, while most of the domical volcanoes are at the top of the stratigraphic column. Analysis of the gravity signatures in the spatial and spectral domains shows a strong correlation between the absence of post-dating features and the presence of dynamic support by an underlying plume. We infer that the formation of the central depressions occurred as a result of cessation of dynamic support. However, there are some domical volcanoes whose geologic histories and gravity signatures also indicate that they are extinct, so sagging of the central region apparently does not always occur when dynamic support is removed. We suggest that the thickness of the elastic lithosphere may be a factor in determining whether a central depression forms when dynamic support is removed, but the gravity data are of insufficient resolution to test this hypothesis with admittance methods.

Herrick, Robert R.; Dufek, Josef; McGovern, Patrick J.

2005-01-01

423

Shielding Calculations for NSLS-II Beamlines.  

SciTech Connect

Brookhaven National Laboratory is in the process of designing a new Electron Synchrotron for scientific research using synchrotron radiation. This facility, called the 'National Synchrotron Light Source II' (NSLS-II), will provide x-ray radiation of ultra-high brightness and exceptional spatial and energy resolution. It will also provide advanced insertion devices, optics, detectors, and robotics, and a suite of scientific instruments designed to maximize the scientific output of the facility. The project scope includes the design, construction, installation, and commissioning of the following accelerators: a 200 MeV linac, a booster accelerator operating from 200 MeV to 3.0 GeV, the storage ring which stores 500 mA current of electrons at an energy of 3.0 GeV and 56 beamlines for experiments. It is planned to operate the facility primarily in a top-off mode, thereby maintaining the maximum variation in stored beam current to < 1%. Because of the very demanding requirements for beam emittance and synchrotron radiation brilliance, the beam life-time is expected to be quite low, on the order of 2 hours. Each of the 56 beamlines will be unique in terms of the source properties and configuration. The shielding designs for five representative beamlines are discussed in this paper.

Job,P.K.; Casey, W.R.

2008-04-13

424

INTOR first wall/blanket/shield activity  

SciTech Connect

The main emphasis of the INTOR first wall/blanket/shield (FWBS) during this period has been upon the tritium breeding issues. The objective is to develop a FWBS concept which produces the tritium requirement for INTOR operation and uses a small fraction of the first wall surface area. The FWBS is constrained by the dimensions of the reference design and the protection criteria required for different reactor components. The blanket extrapolation to commercial power reactor conditions and the proper temperature for power extraction have been sacrificed to achieve the highest possible local tritium breeding ratio (TBR). In addition, several other factors that have been considered in the blanket survey study include safety, reliability, lifetime fluence, number of burn cycles, simplicity, cost, and development issues. The implications of different tritium supply scenarios were discussed from the cost and availability for INTOR conditions. A wide variety of blanket options was explored in a preliminary way to determine feasibility and to see if they can satisfy the INTOR conditions. This survey and related issues are summarized in this report. Also discussed are material design requirements, thermal hydraulic considerations, structure analyses, tritium permeation through the first wall into the coolant, and tritium inventory.

Gohar, Y.; Billone, M.C.; Cha, Y.S.; Finn, P.A.; Hassanein, A.M.; Liu, Y.Y.; Majumdar, S.; Picologlou, B.F.; Smith, D.L.

1986-01-01

425

Addendum to NuMI shielding assessment  

SciTech Connect

The original safety assessment and the Safety Envelope for the NuMI beam line corresponds to 400 kW of beam power. The Main Injector is currently capable of and approved for producing 500 kW of beam power2. However, operation of the NuMI beam line at 400 kW of power brings up the possibility of an occasional excursion above 400 kW due to better than usual tuning in one of the machines upstream of the NuMI beam line. An excursion above the DOE approved Safety Envelope will constitute a safety violation. The purpose of this addendum is to evaluate the radiological issues and modifications required to operate the NuMI beam line at 500 kW. This upgrade will allow 400 kW operations with a reasonable safety margin. Configuration of the NuMI beam line, boundaries, safety system and the methodologies used for the calculations are as described in the original NuMI SAD. While most of the calculations presented in the original shielding assessment were based on Monte Carlo simulations, which were based on the design geometries, most of the results presented in this addendum are based on the measurements conducted by the AD ES&H radiation safety group.

Vaziri, Kamran; /Fermilab

2007-10-01

426

Monte Carlo Shielding Analysis Capabilities with MAVRIC  

SciTech Connect

Monte Carlo shielding analysis capabilities in SCALE 6 are centered on the CADIS methodology Consistent Adjoint Driven Importance Sampling. CADIS is used to create an importance map for space/energy weight windows as well as a biased source distribution. New to SCALE 6 are the Monaco functional module, a multi-group fixed-source Monte Carlo transport code, and the MAVRIC sequence (Monaco with Automated Variance Reduction Using Importance Calculations). MAVRIC uses the Denovo code (also new to SCALE 6) to compute coarse-mesh discrete ordinates solutions which are used by CADIS to form an importance map and biased source distribution for the Monaco Monte Carlo code. MAVRIC allows the user to optimize the Monaco calculation for a specify tally using the CADIS method with little extra input compared to a standard Monte Carlo calculation. When computing several tallies at once or a mesh tally over a large volume of space, an extension of the CADIS method called FW-CADIS can be used to help the Monte Carlo simulation spread particles over phase space to get more uniform relative uncertainties.

Peplow, Douglas E. [ORNL

2011-01-01

427

Nutrient Shielding in Clusters of Cells  

PubMed Central

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 ? 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 ? that characterizes the absorption strength of each cell. The parameter ? can vary over many orders of magnitude between different cell types, ranging from bacteria and yeast to human tissue. The thickness ? decreases with increasing ?, increasing cell volume fraction ?, and decreasing ambient nutrient concentration ??. The theoretical results are compared with numerical simulations and experiments. In the latter studies, colonies of budding yeast, Saccharomyces cerevisiae, are grown on glucose media and imaged under a confocal microscope. We measure the growth inside the colonies via a fluorescent protein reporter and compare the experimental and theoretical results for the thickness ?. PMID:23848711

Lavrentovich, Maxim O.; Koschwanez, John H.; Nelson, David R.

2014-01-01

428

Reflecting ablating heat shields for planetary entry.  

NASA Technical Reports Server (NTRS)

Heat shielding for planetary entry probes of future Jovian and Venusian missions will encounter heating levels well beyond those previously experienced. These entries are typically dominated by radiative heating from the shock layer. This paper demonstrates the potential of reflecting this incident radiation diffusely from an ablating material. This technique contrasts with the absorption experienced by char-forming or graphitic ablators. Two dielectric materials, Teflon (polytetra-fluoroethylene) and boron nitride, are examined for their ablative performance, including reflection, in a combined convective- and radiative-heating environment. For Teflon, at the conditions obtained, superimposition of radiative heating upon a convective stream causes no additional increase in surface recession over the convective only results. For boron nitride, an excellent room-temperature reflector in the visible spectrum, a decrease in reflectivity from 90 to 55 percent is experienced when the surface undergoes sublimation at high temperatures. The process of reflection in each of these materials is described in terms of backscattering from crystals. The significance of a sizable reflection as a mode of energy accommodation is demonstrated for Venusian entries as a potential reduction in mass loss due to ablation.

Peterson, D. L.; Nachtsheim, P. R.; Howe, J. T.

1972-01-01

429

Concrete enclosure for shielding a neutron source.  

PubMed

In the aim to design a shielding for a 0.185 TBq (239)PuBe isotopic neutron source several Monte Carlo calculations were carried out using MCNP5 code. First, a point-like source was modeled in vacuum and the neutron spectrum and ambient dose equivalent were calculated at several distances ranging from 5 cm up to 150 cm, these calculations were repeated modeling a real source, including air, and a 1×1×1 m(3) enclosure with 5, 15, 20, 25, 30, 50 and 80 cm-thick Portland type concrete walls. At all the points located inside the enclosure neutron spectra from 10(-8) up to 0.5 MeV were the same regardless the distance from the source showing the room-return effect in the enclosure, for energies larger than 0.5 MeV neutron spectra are diminished as the distance increases. Outside the enclosure it was noticed that neutron spectra becomes "softer" as the concrete thickness increases due to reduction of mean neutron energy. With the ambient dose values the attenuation curve in terms of concrete thickness was calculated. PMID:23722073

Vega-Carrillo, H R; Villagrana-Muñoz, L E; Rivera-Perez, E; de Leon-Martinez, H A; Soto-Bernal, T G; Hernández-Davila, V M

2013-09-01

430

Nutrient shielding in clusters of cells  

NASA Astrophysics Data System (ADS)

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 ? 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 ? that characterizes the absorption strength of each cell. The parameter ? can vary over many orders of magnitude among different cell types, ranging from bacteria and yeast to human tissue. The thickness ? decreases with increasing ?, increasing cell volume fraction ?, and decreasing ambient nutrient concentration ??. The theoretical results are compared with numerical simulations and experiments. In the latter studies, colonies of budding yeast, Saccharomyces cerevisiae, are grown on glucose media and imaged under a confocal microscope. We measure the growth inside the colonies via a fluorescent protein reporter and compare the experimental and theoretical results for the thickness ?.

Lavrentovich, Maxim O.; Koschwanez, John H.; Nelson, David R.

2013-06-01

431

Electric field shielding in dielectric nanosolutions  

E-print Network

To gain some insight into electrochemical activity of dielectric colloids of technical and biomedical interest we investigate a model of dielectric nanosolution whose micro-constitution is dominated by dipolarions -- positively and negatively charged spherically symmetric nano-structures composed of ionic charge surrounded by cloud of radially polarized dipoles of electrically neutral molecules of solvent. Combing the standard constitutive equations of an isotropic dielectric liquid with Maxwell equation of electrostatics and presuming the Boltzmann shape of the particle density of bound-charge we derive equation for the in-medium electrostatic field. Particular attention is given to numerical analysis of obtained analytic solutions of this equation describing the exterior fields of dipolarions with dipolar atmospheres of solvent molecules endowed with either permanent or field-induced dipole moments radially polarized by central symmetric field of counterions. The presented computations show that the electric field shielding of dipolarions in dielectric nanosolutions is quite different from that of counterionic nano-complexes of Debye-H\\"uckel theory of electrolytes.

Sergey Bastrukov; Pik-Yin Lai; Irina Molodtsova

2011-09-20

432

Building information modeling for sustainable design and LEED ® rating analysis  

Microsoft Academic Search

Today, there is a high level of demand for sustainable buildings. The most important decisions regarding a building's sustainable features are made during the design and preconstruction stages. Leadership in Energy and Environmental Design (LEED®) is the most widely adopted sustainable building rating system in the United States. For projects pursuing LEED® certification, designers have to conduct in-depth sustainability analyses

Salman Azhar; Wade A. Carlton; Darren Olsen; Irtishad Ahmad

2011-01-01

433

Summertime Temperatures in Buildings Without Air-Conditioning.  

ERIC Educational Resources Information Center

Many modern buildings become uncomfortably warm during sunny spells in the summer, and until recently there was no simple, reliable method of assessing at the design stage whether a building would become overheated. This paper describes a method of calculating summertime temperatures which was developed at the Building Research Station, and gives…

Loudon, A. G.

434

SPERTI Instrument Cell Building (PER606) elevation; plan of Guard House ...  

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

SPERT-I Instrument Cell Building (PER-606) elevation; plan of Guard House (PER-607); elevations for Pit Building (PER-605) southwest, southeast, and northeast sides. Earthen shield is mounded between back wall of Instrument Cell Building and the southwest elevation of Pit Building. Detail of filtered louver in door of Instrument Cell Building. Idaho Operations Office PER-605-IDO-3. INEEL index no. 761-0605-00-396-109183 - Idaho National Engineering Laboratory, SPERT-I & Power Burst Facility Area, Scoville, Butte County, ID

435

Staging and Staging Application in Osteomyelitis  

Microsoft Academic Search

Osteomyelitis is traditionally staged by the Waldvogel classification system. The Waldvogel classi- fication is an etiologic system and does not readily lend itself to guiding surgical or antibiotic therapy. Other classifications have been developed to emphasize different clinical aspects of osteomy- elitis. These classifications include those of Ger, Kelly, Weiland, Gordon, May, and Cierny-Mader. The Cierny-Mader classification is based on

Jon T. Mader; Mark Shirtliff; Jason H. Calhoun

1997-01-01

436

Mountain Building  

NSDL National Science Digital Library

This site offers several sets of questions for students to answer about where mountain ranges are located and why they are where they are. Many of the questions have links to more information and/or images. Questions address the role of plate tectonics in the process of mountain building. A computer isn't necessary to answer the questions, but is highly recommended so that the students can use the links provided. These questions require some prior knowledge of the content.

437

Building Bridges  

NSDL National Science Digital Library

In this lesson, students build bridges from arithmetical to algebraic thinking by exploring problems that are not limited to single-solution responses. Values organized into tables and graphs are used to move toward symbolic representations. Problem situations at the middle school level involve linear, quadratic, and exponential models. The site is valuable not only for its problems for students but also for the teaching strategy illustrated here.

Day, Roger; Illustrations, Nctm

2000-01-01

438

Bridge Building  

NSDL National Science Digital Library

This is a quick activity (on page 2 of the PDF) about how the arrangement of carbon atoms determines carbon's different properties. Learners will build bridges with Post-It notes that model two types of carbon molecules, graphite and carbon nanotubes, and test which structure of the same material can bear the weight of the most pennies. Also relates to linked video, DragonflyTV Nano: Hockey Sticks.

Twin Cities Public Television, Inc.

2008-01-01

439

Mountain Building  

NSDL National Science Digital Library

This activity is part of a series of lessons in a continuing study of change. It is designed to give students hands-on experience manipulating and controlling the variables involved in the process of soil erosion. They will be able to identify variables that influence rates of change and use group consensus to design and build what they believe to be the strongest mountain possible.

1998-01-01

440

California commercial building energy benchmarking  

SciTech Connect

Building energy benchmarking is the comparison of whole-building energy use relative to a set of similar buildings. It provides a useful starting point for individual energy audits and for targeting buildings for energy-saving measures in multiple-site audits. Benchmarking is of interest and practical use to a number of groups. Energy service companies and performance contractors communicate energy savings potential with ''typical'' and ''best-practice'' benchmarks while control companies and utilities can provide direct tracking of energy use and combine data from multiple buildings. Benchmarking is also useful in the design stage of a new building or retrofit to determine if a design is relatively efficient. Energy managers and building owners have an ongoing interest in comparing energy performance to others. Large corporations, schools, and government agencies with numerous facilities also use benchmarking methods to compare their buildings to each other. The primary goal of Task 2.1.1 Web-based Benchmarking was the development of a web-based benchmarking tool, dubbed Cal-Arch, for benchmarking energy use in California commercial buildings. While there were several other benchmarking tools available to California consumers prior to the development of Cal-Arch, there were none that were based solely on California data. Most available benchmarking information, including the Energy Star performance rating, were developed using DOE's Commercial Building Energy Consumption Survey (CBECS), which does not provide state-level data. Each database and tool has advantages as well as limitations, such as the number of buildings and the coverage by type, climate regions and end uses. There is considerable commercial interest in benchmarking because it provides an inexpensive method of screening buildings for tune-ups and retrofits. However, private companies who collect and manage consumption data are concerned that the identities of building owners might be revealed and hence are reluctant to share their data. The California Commercial End Use Survey (CEUS), the primary source of data for Cal-Arch, is a unique source of information on commercial buildings in California. It has not been made public; however, it was made available by CEC to LBNL for the purpose of developing a public benchmarking tool.

Kinney, Satkartar; Piette, Mary Ann

2003-07-01

441

Structural-kinematic parageneses of the basement and cover at the southeastern margin of the Baltic Shield  

NASA Astrophysics Data System (ADS)

Through, long-lived structural-kinematic parageneses were established in the southeastern marginal part of the Baltic Shield on the basis of structural studies. These parageneses were formed and periodically rejuvenated from at least the Paleoproterozoic until the neotectonic stage of the evolution of this territory. A series of consecutive tectonic events related to the vertical and horizontal mobility of rocks of the crystalline basement and sedimentary cover had important implications for the formation of present-day structure of the southeastern margin of the Baltic Shield. These tectonic displacements developed for an extremely long time with retention of the main kinematic tendencies. At the end of the Paleoproterozoic, the volcanic and sedimentary rocks of the Vetreny Belt underwent tectonic stacking as a result of the countermotion of the crystalline masses of the Vodlozero Massif and the Belomorian-Lapland Belt. The clockwise rotation and lateral displacement of the Vodlozero Massif to the northeast provided the left-lateral transpression of the Vetreny Belt. Under these conditions, the Paleoproterozoic sequences experienced squeezing in the southeastern direction. This kinematic tendency was retained at the subsequent evolutional stages and eventually was recorded in the structure of the present-day boundary between the Baltic Shield and the Russian Platform.

Kolodyazhny, S. Yu.; Zykov, D. S.; Leonov, M. G.

2007-11-01

442

Music stage design  

NASA Astrophysics Data System (ADS)

Until comparatively recently the specific acoustic needs of performers, and the means of satisfying these, has played second fiddle to the achievement of satisfactory audience listening conditions in auditoria. This paper presents a personal view of music stage design based on the author's experience in architecture and acoustics and on the results of recent research. Local reflections and the possible influence of stage and auditorium rake are discussed and guidelines for the salient features of orchestral stages are suggested.

Allen, W. A.

1980-03-01

443

Staged laser plasma accelerators  

NASA Astrophysics Data System (ADS)

We present current results on staged electron acceleration in the LOASIS program at the Lawrence Berkeley National Laboratory. The goal is to experimentally demonstrate laser driven electron acceleration in two stages, where each stage is driven by a separate laser pulse. This technology could provide the key to built compact laser driven accelerators which could potentially reach up to TeV in electron energy.

Sokollik, Thomas; Shiraishi, Satomi; Shaw, Brian; Gonsalves, Antony; Nakamura, Kei; van Tilborg, Jeroen; Esarey, Eric; Schroeder, Carl B.; Benedetti, Carlo; Toth, Csaba; Leemans, Wim

2012-12-01

444

A small satellite preliminary thermal control and heat shield analysis  

E-print Network

As part of a student owned small satellite project, a preliminary thermal control and heat shield analysis was developed to verify acceptable performance requirements for the system. For the thermal control section, the ...

Melani Barreiro, Diego A

2008-01-01

445

Could Wine, Chocolate Help Shield Your Heart from Smog?  

MedlinePLUS

... Help Shield Your Heart From Smog? Researchers say air pollution's effects lessened in older men who consumed flavonoids, ... 2015) Monday, November 17, 2014 Related MedlinePlus Pages Air Pollution Antioxidants Heart Diseases MONDAY, Nov. 17, 2014 (HealthDay ...

446

A Radiation shielding study for the Fermilab Linac  

SciTech Connect

Radiation shielding calculations are performed for the Fermilab Linac enclosure and gallery. The predicted dose rates around the access labyrinth at normal operation and a comparison to measured dose rates are presented. An accident scenario is considered as well.

Rakhno, I.; Johnstone, C.; /Fermilab

2006-02-01

447

Space mapping method for the design of passive shields  

NASA Astrophysics Data System (ADS)

The aim of the paper is to find the optimal geometry of a passive shield for the reduction of the magnetic stray field of an axisymmetric induction heater. For the optimization, a space mapping algorithm is used that requires two models. The first is an accurate model with a high computational effort as it contains finite element models. The second is less accurate, but it has a low computational effort as it uses an analytical model: the shield is replaced by a number of mutually coupled coils. The currents in the shield are found by solving an electrical circuit. Space mapping combines both models to obtain the optimal passive shield fast and accurately. The presented optimization technique is compared with gradient, simplex, and genetic algorithms.

Sergeant, Peter; Dupré, Luc; Melkebeek, Jan

2006-04-01

448

21 CFR 892.6500 - Personnel protective shield.  

Code of Federal Regulations, 2012 CFR

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Miscellaneous Devices § 892.6500 Personnel protective shield. (a) Identification. A...

2012-04-01

449

21 CFR 892.6500 - Personnel protective shield.  

Code of Federal Regulations, 2010 CFR

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Miscellaneous Devices § 892.6500 Personnel protective shield. (a) Identification. A...

2010-04-01

450

21 CFR 892.6500 - Personnel protective shield.  

Code of Federal Regulations, 2011 CFR

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Miscellaneous Devices § 892.6500 Personnel protective shield. (a) Identification. A...

2011-04-01

451

21 CFR 892.6500 - Personnel protective shield.  

Code of Federal Regulations, 2013 CFR

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Miscellaneous Devices § 892.6500 Personnel protective shield. (a) Identification. A...

2013-04-01

452

21 CFR 892.6500 - Personnel protective shield.  

... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Miscellaneous Devices § 892.6500 Personnel protective shield. (a) Identification. A...

2014-04-01

453

Low Temperature Studies of Anomalous Surface Shielding and Related Phenomena.  

National Technical Information Service (NTIS)

Experiments were conducted to determine the force of gravity on positions and electrons. An anomalous, low temperature shielding effect was discovered in copper and studied. It is believed that sharp increases in the microwave surface conductivity of copp...

W. M. Fairbank

1986-01-01

454

Lightning-activated electrical ground for cable shields  

NASA Technical Reports Server (NTRS)

Device protects cables used to connect circuits that are physically separated from lightning-induced high-voltage. Circuit returns to normal high impedance open configuration after lightning-induced shield voltage is dissipated.

Castle, K. D.

1977-01-01

455

63. REACTOR CHAMBER (BASF) FROM NORTH SHOWING NEUTRON SHIELD TANK ...  

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

63. REACTOR CHAMBER (BASF) FROM NORTH SHOWING NEUTRON SHIELD TANK AND REACTOR PIPING (LOCATION RRR) - Shippingport Atomic Power Station, On Ohio River, 25 miles Northwest of Pittsburgh, Shippingport, Beaver County, PA

456

Thermal Insulation of Wet Shielded Metal Arc Welds.  

National Technical Information Service (NTIS)

Computational and experimental studies were performed to determine the effect of static thermal insulation on the quality of wet shielded metal arc welds (SMAW). A commercially available heat flow and fluid dynamics spectral-element computer program was u...

P. J. Keenan

1993-01-01

457

IET. Typical detail during Snaptran reactor experiments. Shielding bricks protect ...  

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

IET. Typical detail during Snaptran reactor experiments. Shielding bricks protect ion chamber beneath reactor on dolly. Photographer: Page Comiskey. Date: August 11, 1965. INEEL negative no. 65-4039 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID

458

Ballistic resistance of multi-layered steel shields  

E-print Network

In this thesis, the ballistic resistance of multi-layered steel shields against projectile impact at the sub-ordnance velocity is evaluated using finite element simulations. Eight types of projectiles of different weight ...

Huang, Min, S.M. Massachusetts Institute of Technology

2007-01-01

459

SHIELDING DOORS FOR SUBPILE ROOM WERE FABRICATED ON SITE. INL ...  

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

SHIELDING DOORS FOR SUB-PILE ROOM WERE FABRICATED ON SITE. INL NEGATIVE NO. 958. Unknown Photographer, 11/8/1950 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

460

Magnetic shielding tests for MFTF-B neutral beamlines  

SciTech Connect

A test program to determine the effectiveness of various magnetic shielding designs for MFTF-B beamlines was established at Lawrence Livermore National Laboratory (LLNL). The proposed one-tenth-scale shielding-design models were tested in a uniform field produced by a Helmholtz coil pair. A similar technique was used for the MFTF source-injector assemblies, and the model test results were confirmed during the Technology Demonstration in 1982. The results of these tests on shielding designs for MFTF-B had an impact on the beamline design for MFTF-B. The iron-core magnet and finger assembly originally proposed were replaced by a simple, air-core, race-track-coil, bending magnet. Only the source injector needs to be magnetically shielded from the fields of approximately 400 gauss.

Kerns, J.; Fabyan, J.; Wood, R.; Koger, P.

1983-11-16

461

Effect of Building Frame and Moisture Damage on Microbiological Indoor Air Quality in School Buildings  

Microsoft Academic Search

The effect of building frame and moisture damage on microbial indoor air quality was characterized in 17 wooden and 15 concrete or brick school buildings. Technical investigations to detect visible moisture and mold damage were performed according to a standardized protocol. Viable airborne microbes were determined by using a six-stage impactor (Andersen 10–800). Mean concentrations of viable airborne fungi were

Teija Meklin; Anne Hyvärinen; Mika Toivola; Tiina Reponen; Virpi Koponen; Tuula Husman; Taina Taskinen; Matti Korppi; Aino Nevalainen

2003-01-01

462

Five Stages of Flow  

NSDL National Science Digital Library

This website includes an animation which shows the stages that molecules go through as they move from the turbulent stage of viscous flow, transition into laminar flow, and then transition again into molecular flow. You may pause this animation between stages. Objective: Identify the five stages of flow. This simulation is from Module 98 of the Vacuum Technology and Gas Control Cluster of the MATEC Module Library (MML). You can find this animation under the section "Vacuum Technology & Gas Controls." To view other clusters or for more information about the MML visit http://matec.org/ps/library3/process_I.shtmlKey

2012-11-20

463

Radiation shielding in transit to Mars and on the surface  

NASA Technical Reports Server (NTRS)

An evaluation is presented of the current understanding of the space radiation environment and the primary considerations of spacecrew exposure effects and limits. By using a two-solar particle event scenario for a 'sprint' mission to Mars, estimates are developed for the requisite shielding of the transfer vehicle and Martian surface habitat. Many uncertainties, however, are noted to have gone into these mission dose estimates; the combination of these uncertainties into an error-bar on shield mass lies beyond current capabilities.

Conway, Edmund J.; Townsend, Lawrence W.

1992-01-01

464

BrowserShield: Vulnerability-Driven Filtering of Dynamic HTML  

Microsoft Academic Search

Vulnerability-driven filtering of network data can offer a fast and easy-to-deploy alternative or intermediary to software patching, as exemplified in Shield (43). In this paper, we take Shield's vision to a new domain, inspect- ing and cleansing not just static content, but also dy- namic content. The dynamic content we target is the dynamic HTML in web pages, which have

Charles Reis; John Dunagany; Helen J. Wangy Opher

465

Shielding effectiveness of conducting polyaniline coated fabrics at 101 GHz  

Microsoft Academic Search

Conducting polyaniline coated fabrics can be used as a shield material for the control of electromagnetic interference at 101GHz. The conducting fabrics can also be used for the dissipation of electrostatic charge. The conducting fabric shows a shielding effectiveness of 35.61dB. The characterization of the conducting polymer polyaniline and conducting fabrics was carried by spectroscopic techniques and thermogravimetric analysis. Static

S. K Dhawan; N Singh; S Venkatachalam

2001-01-01

466

Small domes on Venus - Probable analogs of Icelandic lava shields  

NASA Technical Reports Server (NTRS)

On the basis of observed shapes and volumetric estimates, small, dome-like features on radar images of Venus are interpreted to be analogs of Icelandic lava-shield volcanoes. Morphometric data for Venusian domes in Aubele and Slyuta as well as measurements of representative dome volumes and areas from Tethus Regio are used to demonstrate that the characteristic aspect ratios and flank slopes of these features are consistent with a subclass of low Icelandic lava-shield volcanoes (LILS).

Garvin, James B.; Williams, Richard S., Jr.

1990-01-01

467

BrowserShield: Vulnerability-Driven Filtering of Dynamic HTML  

Microsoft Academic Search

Vulnerability-driven filtering of network data can offer a fast and easy-to-deploy alternative or intermediary to software patching, as exemplified in Shield (43). In this paper, we take Shield's vision to a new domain, inspect- ing and cleansing not just static content, but also dy- namic content. The dynamic content we target is the dynamic HTML in web pages, which have

Charles Reis; John Dunagan; Helen J. Wang; Opher Dubrovsky; Saher Esmeir

2006-01-01

468

Gravity Scaling of a Power Reactor Water Shield  

NASA Technical Reports Server (NTRS)

A similarity analysis on a water-based reactor shield examined the effect of gravity on free convection between a reactor shield inner and outer vessel boundaries. Two approaches established similarity between operation on the Earth and the Moon: 1) direct scaling of Rayleigh number equating gravity-surface heat flux products, 2) temperature difference between the wall and thermal boundary layer held constant. Nusselt number for natural convection (laminar and turbulent) is assumed of form Nu = CRa(sup n).

Reid, Robert S.; Pearson, J. Boise

2007-01-01

469

Noise Modeling From Conductive Shields Using Kirchhoff Equations  

PubMed Central

Progress in the development of high-sensitivity magnetic-field measurements has stimulated interest in understanding the magnetic noise of conductive materials, especially of magnetic shields based on high-permeability materials and/or high-conductivity materials. For e