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1

Automated Core Design  

SciTech Connect

Multistate searching methods are a subfield of distributed artificial intelligence that aims to provide both principles for construction of complex systems involving multiple states and mechanisms for coordination of independent agents' actions. This paper proposes a multistate searching algorithm with reinforcement learning for the automatic core design of a boiling water reactor. The characteristics of this algorithm are that the coupling structure and the coupling operation suitable for the assigned problem are assumed and an optimal solution is obtained by mutual interference in multistate transitions using multiagents. Calculations in an actual plant confirmed that the proposed algorithm increased the convergence ability of the optimization process.

Kobayashi, Yoko; Aiyoshi, Eitaro

2005-07-15

2

Automatic core design using reinforcement learning  

Microsoft Academic Search

This paper deals with the application of multi-agents algorithm to the core design tool in a nuclear industry. We develop an original solution algorithm for the automatic core design of boiling water reactor using multi-agents and reinforcement learning. The characteristics of this algorithm are that the coupling structure and the coupling operation suitable for the assigned problem are assumed, and

Y. Kobayashi; Eitaro Aiyoshi

2004-01-01

3

Recent Problems of Transformer Core Design  

NASA Astrophysics Data System (ADS)

The paper describes the result of the investigations of the efficiency of power loss reduction in transformer cores made with high-permeability (HGO) and laser scribed (LS) grain-oriented electrical steels, and also the phenomena in three-limb three-phase cores with the so-called staggered T-joint design. The efficiency of the HGO material depends on core form and core induction. The efficiency is better for single-phase than for three-phase cores and also for higher induction. The localised efficiency of HGO material is not uniform and it is significantly lower in the yoke than in other parts. The efficiency of LS material (grade ZDKH) is better than that of the HGO material and also somewhat higher for single-phase than for three-phase cores. The localised flux distribution in the central limb of the core with staggered T-joint is more uniform and the content of higher harmonics is smaller than in the core with conventional V-45° T-joint. This results in a 13% loss reduction in the central limb and in a 4-5% reduction of total core loss.

Valkovic, Z.

1988-01-01

4

Advanced High Temperature Reactor Neutronic Core Design  

SciTech Connect

The AHTR is a 3400 MW(t) FHR class reactor design concept intended to serve as a central generating station type power plant. While significant technology development and demonstration remains, the basic design concept appears sound and tolerant of much of the remaining performance uncertainty. No fundamental impediments have been identified that would prevent widespread deployment of the concept. This paper focuses on the preliminary neutronic design studies performed at ORNL during the fiscal year 2011. After a brief presentation of the AHTR design concept, the paper summarizes several neutronic studies performed at ORNL during 2011. An optimization study for the AHTR core is first presented. The temperature and void coefficients of reactivity are then analyzed for a few configurations of interest. A discussion of the limiting factors due to the fast neutron fluence follows. The neutronic studies conclude with a discussion of the control and shutdown options. The studies presented confirm that sound neutronic alternatives exist for the design of the AHTR to maintain full passive safety features and reasonable operation conditions.

Ilas, Dan [ORNL] [ORNL; Holcomb, David Eugene [ORNL] [ORNL; Varma, Venugopal Koikal [ORNL] [ORNL

2012-01-01

5

Energy Efficient Engine core design and performance report  

NASA Technical Reports Server (NTRS)

The Energy Efficient Engine (E3) is a NASA program to develop fuel saving technology for future large transport aircraft engines. Testing of the General Electric E3 core showed that the core component performance and core system performance necessary to meet the program goals can be achieved. The E3 core design and test results are described.

Stearns, E. Marshall

1982-01-01

6

New Designs for NMR Core Scanning  

NASA Astrophysics Data System (ADS)

Within the last ten years, mobile magnetic resonance has moved from the oil field to many new areas of application. While the focus of mobile NMR in the past was on single-sided or inside-out NMR, the advent of tube-shaped Halbach magnets has introduced the conventional outside-in NMR concept to mobile NMR where the object is inside a magnet. Our Halbach magnet is constructed from small magnet blocks at light weight and low cost with a magnetic field sufficiently homogeneous. To automatize NMR measurements, the Halbach magnet is mounted on a sliding table to scan long core sections without human interaction. In homogeneous magnetic fields, the longitudinal relaxation time T1 and even the transverse relaxation time T2 are proportional to the pore diameters of rocks. Hence, the T1 and T2 signals map the pore-size distribution of the studied rock cores. For fully saturated samples the integral of the distribution curve is proportional to porosity. The porosity values from NMR measurements with the Halbach magnet are used to estimate permability. The Halbach magnet can be used for certain sample geometries in combination with exchangeable radio frequency (rf) coils with different diameters from 24 mm up to 80 mm. To measure standard Ocean Drilling Program (ODP)/Integrated Ocean Drilling Program (IODP) cores, which have a standard diameter of 60 mm and are split lengthwise after recovery, we use a surface figure-8 rf coil with an inner diameter of 60 mm. Besides 1D T2 measurements, we perform relaxation-relaxation correlation experiments, where T1 and T2 are measured in parallel. In this way, the influence of diffusion on the shape of the T2 distribution function is probed. A gradient coil system was designed to perform Pulsed Field Gradients (PFG) experiments. As the gradient coils restrict the axial access to the magnet, only cylindrical core plugs with 20 mm in diameter can be analysed by PFG NMR methods. The homogeneity of the magnetic field in the sensitive volume of 20 mm length and height is sufficient for conventional PFG experiments. Hence, in a next step we will measure tortuosity and investigate pore anisotropies by PFG NMR.

Bluemich, B.; Anferova, S.; Talnishnikh, E.; Arnold, J.; Clauser, C.

2006-12-01

7

IP core design of template matching algorithm in image processing  

NASA Astrophysics Data System (ADS)

This paper presents the design and implementation of template matching IP cores for image processing. Enhanced Moment Preserving Pattern Matching (MPPM) algorithm of template matching was adopted for efficient hardware implementation. The cores were coded in Verilog HDL for modularity and portability. The IP cores were validated in a XC4052XL FPGA and XESS XS40 prototyping board.

Zhu, Quanqing; Zou, Xuecheng; Dong, Zhenzhong; Huang, Feng; Shen, Xubang

2001-09-01

8

Core bit design reduces mud invasion, improves ROP  

SciTech Connect

A recently developed core bit reduces fluid invasion in the cut core by minimizing the exposure to the drilling fluid and by increasing the rate of penetration (ROP). A high ROP during coring is one of the major factors in reducing mud filtrate invasion in cores. This new low-invasion polycrystalline diamond compact (PDC) core bit was designed to achieve a higher ROP than conventional PDC core bits without detriment to the cutting structure. The paper describes the bit and its operation, results of lab tests, fluid dynamics, and results of field tests.

Clydesdale, G. (Security DBS, Aberdeen (United Kingdom)); Leseultre, A.; Lamine, E. (Security DBS, Brussels (Belgium))

1994-08-08

9

Specifics of RBMK core cooling in beyond design basis accidents  

Microsoft Academic Search

The most dangerous beyond design basis accidents for RBMK reactors, leading to the worst consequences, are related to the loss of long-term heat removal from the core. Due to a specific design of RBMK, there are a few possibilities for heat removal from reactor core by non-regular means: removal of heat from graphite stack by reactor gas circuit, removal of

A. Kaliatka; E. Ušpuras

2008-01-01

10

Conceptual design of an in-vessel core catcher  

Microsoft Academic Search

An enhanced in-vessel core catcher is being designed and evaluated as part of a joint United States (US)–Korean International Nuclear Energy Research Initiative (INERI) investigating methods to insure retention of materials that may relocate to the lower head of a reactor vessel under severe accident conditions in advanced reactors. This enhanced core catcher design consists of several interlocking sections that

J. L. Rempe; D. L. Knudson; K. G. Condie; K. Y. Suh; F.-B. Cheung; S.-B. Kim

2004-01-01

11

Design considerations for an air core magnetic actuator  

NASA Technical Reports Server (NTRS)

Equations for the force produced by an air core electromagnet on a permanent magnet core as a function of the coil height, coil inner and outer radii, and core displacement are developed. The magnetization vector of the permanent magnet core is assumed to be aligned with the central axis of the electromagnet and the forces which are produced lie along the same axis. Variations in force due to changes in electromagnet parameters and core displacement are investigated and parameter plots which should be useful for coil design are presented.

Groom, Nelson J.

1992-01-01

12

Preliminary engineering design of sodium-cooled CANDLE core  

NASA Astrophysics Data System (ADS)

The CANDLE burning process is characterized by the autonomous shifting of burning region with constant reactivity and constant spacial power distribution. Evaluations of such critical burning process by using widely used neutron diffusion and burning codes under some realistic engineering constraints are valuable to confirm the technical feasibility of the CANDLE concept and to put the idea into concrete core design. In the first part of this paper, it is discussed that whether the sustainable and stable CANDLE burning process can be reproduced even by using conventional core analysis tools such as SLAROM and CITATION-FBR. As a result, it is certainly possible to demonstrate it if the proper core configuration and initial fuel composition required as CANDLE core are applied to the analysis. In the latter part, an example of a concrete image of sodium cooled, metal fuel, 2000MWt rating CANDLE core has been presented by assuming an emerging inevitable technology of recladding. The core satisfies engineering design criteria including cladding temperature, pressure drop, linear heat rate, and cumulative damage fraction (CDF) of cladding, fast neutron fluence and sodium void reactivity which are defined in the Japanese FBR design project. It can be concluded that it is feasible to design CADLE core by using conventional codes while satisfying some realistic engineering design constraints assuming that recladding at certain time interval is technically feasible.

Takaki, Naoyuki; Namekawa, Azuma; Yoda, Tomoyuki; Mizutani, Akihiko; Sekimoto, Hiroshi

2012-06-01

13

Preliminary engineering design of sodium-cooled CANDLE core  

SciTech Connect

The CANDLE burning process is characterized by the autonomous shifting of burning region with constant reactivity and constant spacial power distribution. Evaluations of such critical burning process by using widely used neutron diffusion and burning codes under some realistic engineering constraints are valuable to confirm the technical feasibility of the CANDLE concept and to put the idea into concrete core design. In the first part of this paper, it is discussed that whether the sustainable and stable CANDLE burning process can be reproduced even by using conventional core analysis tools such as SLAROM and CITATION-FBR. As a result, it is certainly possible to demonstrate it if the proper core configuration and initial fuel composition required as CANDLE core are applied to the analysis. In the latter part, an example of a concrete image of sodium cooled, metal fuel, 2000MWt rating CANDLE core has been presented by assuming an emerging inevitable technology of recladding. The core satisfies engineering design criteria including cladding temperature, pressure drop, linear heat rate, and cumulative damage fraction (CDF) of cladding, fast neutron fluence and sodium void reactivity which are defined in the Japanese FBR design project. It can be concluded that it is feasible to design CANDLE core by using conventional codes while satisfying some realistic engineering design constraints assuming that recladding at certain time interval is technically feasible.

Takaki, Naoyuki; Namekawa, Azuma; Yoda, Tomoyuki; Mizutani, Akihiko; Sekimoto, Hiroshi [Department of Nuclear Engineering, Tokai University, Kitakaname, Hiratsuka, Kanagawa 259-1292 (Japan); AISA, Fuchu, Ishioka, Ibaraki 315-0013 (Japan); Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo, 152-8550 (Japan)

2012-06-06

14

MetaCores: Design and Optimization Techniques Seapahn Meguerdichian1  

E-print Network

, hardware intellectual property (IP) is delivered at three levels of abstraction: hard, firm, and soft. In order to further enhance performance, efficiency, and flexibility of IP design, we have developed a new approach for designing hardware and soft- ware IP called MetaCores. The new design approach starts

Potkonjak, Miodrag

15

One pass core design of a super fast reactor  

SciTech Connect

One pass core design for Supercritical-pressure light water-cooled fast reactor (Super FR) is proposed. The whole core is cooled with upward flow in one through flow pattern like PWR. Compared with the previous two pass core design; this new flow pattern can significantly simplify the core concept. Upper core structure, coolant flow scheme as well as refueling procedure are as simple as in PWR. In one pass core design, supercritical-pressure water is at approximately 25.0 MPa and enters the core at 280 C. degrees and is heated up in one through flow pattern upwardly to the average outlet temperature of 500 C. degrees. Great density change in vertical direction can cause significant axial power offset during the cycle. Meanwhile, Pu accumulated in the UO{sub 2} fuel blanket assemblies also introduces great power increase during cycle, which requires large amount of flow for heat removal and makes the outlet temperature of blanket low at the beginning of equilibrium cycle (BOEC). To deal with these issues, some MOX fuel is applied in the bottom region of the blanket assembly. This can help to mitigate the power change in blanket due to Pu accumulation and to increase the outlet temperature of the blanket during cycle. Neutron transport and thermohydraulics coupled calculation shows that this design can satisfy the requirement in the Super FR principle for both 500 C. degrees outlet temperature and negative coolant void reactivity. (authors)

Liu, Qingjie; Oka, Yoshiaki [Cooperative Major in Nuclear Energy, Waseda University, Tokyo 169-8555 (Japan)

2013-07-01

16

Design. Youth Training Scheme. Core Exemplar Work Based Project.  

ERIC Educational Resources Information Center

This trainer's guide is intended to assist supervisors of work-based career training projects in helping students understand the importance of industrial designers and the stages of the industrial design process. The guide is one in a series of core curriculum modules that is intended for use in combination on- and off-the-job programs to…

Further Education Staff Coll., Blagdon (England).

17

Data Path Design of an Embedded MCU Core  

Microsoft Academic Search

In this paper, the MCU core is partitioned into data path units and control units. Since the data path is one of the key factors that influence the performance of MCU, much effort has invested to its design. A data path model is elaborately designed. ALU is optimized using operand isolation for power reduction. Four-level read scheme is adopted for

Fang Huo; Zu-Qiang Wang; Jian-Hong Zhou; Yi Xie

2006-01-01

18

Conceptual design of an in-vessel core catcher  

SciTech Connect

An enhanced in-vessel core catcher is being designed and evaluated as part of a joint United States (US)–Korean International Nuclear Energy Research Initiative (INERI) investigating methods to insure retention of materials that may relocate to the lower head of a reactor vessel under severe accident conditions in advanced reactors. This enhanced core catcher design consists of several interlocking sections that are machined to fit together when inserted into the lower head. Each section of the core catcher consists of two material layers with an option to add a third layer (if deemed necessary): a base material, which has the capability to support and contain the mass of core materials that may relocate during a severe accident; an insulator coating material on top of the base material, which resists interactions with high-temperature core materials; and an optional coating on the bottom side of the base material to prevent any potential oxidation of the base material during the lifetime of the reactor. This paper summarizes results from thermal, flow, and structural analyses as well as initial scoping materials interaction tests that were completed to support the conceptual design of the core catcher.

Joy L. Rempe; D. L. Knudson; K. G. Condie; K. Y. Suh; F. B.Cheung; S. B. Kim

2004-05-01

19

Core and transient design of a BWR for the next century  

SciTech Connect

Basic parameters for the core and transient design of the BWR for the next century is investigated, and a reference core design is selected for fundamental studies on the core and transient characteristics. A previous paper in ICONE-3 showed that the reference core design has potential for the core design flexibility. This paper reports the basis of the reference core selection in conformity with utilities` requirements and the progress of studies on the core and transient design of the reference core. A new concept called functional control rod layout is selected as a candidate for the reference core.

Yoshioka, R. [Toshiba Corp., Yokohama (Japan); Tanikawa, N. [Hitachi, Ltd., Hitachi, Ibaraki (Japan); Fennern, L.E. [General Electric Nuclear Energy, San Jose, CA (United States); Anegawa, T. [Tokyo Electric Power Co. (Japan)

1996-07-01

20

Core design of the upgraded TREAT reactor  

SciTech Connect

The upgrading of the TREAT reactor involves the replacement of the central 11 x 11 subzone of the 19 x 19 fuel assembly array by new, Inconel-clad, high-temperature fuel assemblies, and the additions of a new reactor control system, a safety-grade plant protection system, and an enhanced reactor filtration/coolant system. The final design of these modifications will be completed in early 1983. The TREAT facility is scheduled to be shut down for modification in mid-1984, and should resume the safety test program in mid-1985. The upgrading will provide a capability to conduct fast reactor safety tests on clusters of up to 37 prototypic LMFBR pins.

Wade, D.C.; Bhattacharyya, S.K.; Lipinski, W.C.; Stone, C.C.

1982-01-01

21

Observer design for a core circadian rhythm network.  

PubMed

The paper investigates the observer design for a core circadian rhythm network in Drosophila and Neurospora. Based on the constructed highly nonlinear differential equation model and the recently proposed graphical approach, we design a rather simple observer for the circadian rhythm oscillator, which can well track the state of the original system for various input signals. Numerical simulations show the effectiveness of the designed observer. Potential applications of the related investigations include the real-world control and experimental design of the related biological networks. PMID:25121122

Zhang, Yuhuan

2014-01-01

22

Implementation of an Arm Compatible Processor Core for SOC Designs  

Microsoft Academic Search

Hardware description languages (HDLs) are commonly used to construct hardware systems. Reuse of the design is a common practice to improve the productivity nowadays. In this paper, an implementation of a fully pipelined ARM compatible processor core, which can be embedded into system-on-chips (SOCs) is presented. The implementation aims to support research, education, and development by opening the source codes.

Ahmed A. Morgan; M. E. Allam; M. A. Salama; H. A. K. Mansour

2005-01-01

23

Two stochastic optimization algorithms applied to nuclear reactor core design  

Microsoft Academic Search

Two stochastic optimization algorithms conceptually similar to Simulated Annealing are presented and applied to a core design optimization problem previously solved with Genetic Algorithms. The two algorithms are the novel Particle Collision Algorithm (PCA), which is introduced in detail, and Dueck's Great Deluge Algorithm (GDA). The optimization problem consists in adjusting several reactor cell parameters, such as dimensions, enrichment and

Wagner F. Sacco; Cassiano R. E. de oliveira; Cláudio M. N. A. Pereira

2006-01-01

24

Core design of supercritical-pressure light water reactor  

SciTech Connect

A large improvement in thermal efficiency can be achieved in a Light Water Reactor (LWR) by using the supercritical-pressure thermal cycle concept. No boiling or phase transition occurs above the critical pressure condition, which leads to a substantial simplification of the system by eliminating the steam separator, the dryers and the steam Generators in a direct cycle. In this feasibility study, the Supercritical-Pressure Light Water Reactor (SCLWR) was analyzed with reference to the experience of conventional LWRs. The main results of fuel, the core, the control rod, the core internals and the reactor vessel designs are presented in this report. The thermal hydraulic design which uses an accurate flow distribution to achieve a high thermal efficiency has been also analyzed. Finally, based on the present results, recommendations have been made for future work.

Tanaka, S.; Shirai, Y.; Mori, M. [Tokyo Electric Co., Yokohama (Japan). Nuclear Power R and D Center] [and others

1996-07-01

25

Beamed Core Antimatter Propulsion: Engine Design and Optimization  

E-print Network

A conceptual design for beamed core antimatter propulsion is reported, where electrically charged annihilation products directly generate thrust after being deflected and collimated by a magnetic nozzle. Simulations were carried out using the Geant4 (Geometry and tracking) software toolkit released by the CERN accelerator laboratory for Monte Carlo simulation of the interaction of particles with matter and fields. Geant permits a more sophisticated and comprehensive design and optimization of antimatter engines than the software environment for simulations reported by prior researchers. The main finding is that effective exhaust speeds Ve ~ 0.69c (where c is the speed of light) are feasible for charged pions in beamed core propulsion, a major improvement over the Ve ~ 0.33c estimate based on prior simulations. The improvement resulted from optimization of the geometry and the field configuration of the magnetic nozzle. Moreover, this improved performance is realized using a magnetic field on the order of 10 T at the location of its highest magnitude. Such a field could be produced with today's technology, whereas prior nozzle designs anticipated and required major advances in this area. The paper also briefly reviews prospects for production of the fuel needed for a beamed core engine.

Ronan Keane; Wei-Ming Zhang

2012-05-16

26

Core compressor exit stage study. 1: Aerodynamic and mechanical design  

NASA Technical Reports Server (NTRS)

The effect of aspect ratio on the performance of core compressor exit stages was demonstrated using two three stage, highly loaded, core compressors. Aspect ratio was identified as having a strong influence on compressors endwall loss. Both compressors simulated the last three stages of an advanced eight stage core compressor and were designed with the same 0.915 hub/tip ratio, 4.30 kg/sec (9.47 1bm/sec) inlet corrected flow, and 167 m/sec (547 ft/sec) corrected mean wheel speed. The first compressor had an aspect ratio of 0.81 and an overall pressure ratio of 1.357 at a design adiabatic efficiency of 88.3% with an average diffusion factor or 0.529. The aspect ratio of the second compressor was 1.22 with an overall pressure ratio of 1.324 at a design adiabatic efficiency of 88.7% with an average diffusion factor of 0.491.

Burdsall, E. A.; Canal, E., Jr.; Lyons, K. A.

1979-01-01

27

Integrating Core Selection in the SOC Test Solution Design-Flow Erik Larsson  

E-print Network

be completely new in-house designs. The core test integrator is responsible for the design of the system's testIntegrating Core Selection in the SOC Test Solution Design-Flow Erik Larsson Embedded Systems a technique to integrate core selection in the SOC (system-on-chip) test solution design-flow. It can

Larsson, Erik

28

Preliminary design study of advanced multistage axial flow core compressors  

NASA Technical Reports Server (NTRS)

A preliminary design study was conducted to identify an advanced core compressor for use in new high-bypass-ratio turbofan engines to be introduced into commercial service in the 1980's. An evaluation of anticipated compressor and related component 1985 state-of-the-art technology was conducted. A parametric screening study covering a large number of compressor designs was conducted to determine the influence of the major compressor design features on efficiency, weight, cost, blade life, aircraft direct operating cost, and fuel usage. The trends observed in the parametric screening study were used to develop three high-efficiency, high-economic-payoff compressor designs. These three compressors were studied in greater detail to better evaluate their aerodynamic and mechanical feasibility.

Wisler, D. C.; Koch, C. C.; Smith, L. H., Jr.

1977-01-01

29

System design description for GCFR-core flow test loop  

SciTech Connect

The Core Flow Test Loop is a high-pressure, high-temperature, out-of-reactor helium circulation system that is being constructed to permit detailed study of the thermomechanical and thermal performance at prototypic steady-state and transient operating conditions of simulated segments of core assemblies for a GCFR Demonstration Plant, as designed by General Atomic Company. It will also permit the expermental verification of predictive analytical models of the GCFR core assemblies needed to reduce operational and safety uncertainties of the GCFR. Full-sized blanket assemblies and segments of fuel rod and control rod fuel assemblies will be simulated with test bundles of electrically powered fuel rod or blanket rod simulators. The loop will provide the steady-state and margin test requirements of bundle power and heat removal, and of helium coolant flow rate, pressure, and temperature for test bundles having up to 91 rods; these requirements set the maximum power, coolant helium flow, and thermal requirements for the loop. However, the size of the test vessel that contains the test bundles will be determined by the bundles that simulate a full-sized GCFR blanket assembly. The loop will also provide for power and coolant transients to simulate transient operation of GCFR core assemblies, including the capability for rapid helium depressurization to simulate the depressurization class of GCFR accidents. In addition, the loop can be used as an out-of-reactor test bed for characterizing in-reactor test bundle configurations.

Huntley, W.R.; Grindell, A.G.

1980-12-01

30

New approach to the design of core support structures for large LMFBR plants  

SciTech Connect

The paper describes an innovative design concept for a LMFBR Core Support Structure. A hanging Core Support Structure is described and analyzed. The design offers inherent safety features, constructibility advantages, and potential cost reductions.

Burelbach, J.P.; Kann, W.J.; Pan, Y.C.; Saiveau, J.G.; Seidensticker, R.W.

1984-01-01

31

General Behavioral Thermal Modeling and Characterization for Multi-core Microprocessor Design  

E-print Network

General Behavioral Thermal Modeling and Characterization for Multi-core Microprocessor Design Thom-performance multi-core microprocessor design. The new approach builds the thermal behavioral models from ability. Experimental results on a real quad-core microprocessor show that ThermSID is more accurate than

Tan, Sheldon X.-D.

32

Negative curvature hollow core fibers: design, fabrication, and applications  

NASA Astrophysics Data System (ADS)

In this paper we consider a new type of hollow core microstructured optical fibers (HC MOFs) so called negative curvature hollow core fibers (NCHCFs). NCHCFs are known as hollow core fibers which allow to transmit a light under extremely high material loss of the cladding material. Such unique property of NCHCFs is due to the fact that their guiding mechanism is different from the guiding mechanisms in hollow core photonic crystal fibers (HC PCFs) and hollow core Bragg fibers (HC BFs). The two main factors which determine the guiding properties of NCHCFs are the `negative curvature' (in a more general case, an alternating curvature) of the core - cladding boundary and the density of electromagnetic states of the cladding. It will be shown that the `negative curvature' of the core - cladding boundary determines the type of interference which can lead to strong light localization in the air core. The interference which leads to air core mode formation in HC PCFs or HC BFs can be considered in terms of a linear momentum transfer by the photonic crystal cladding to the air core modes. In the case of NCHCFs the air core mode formation can be considered in terms of an azimuthal momentum transfer by the core - cladding boundary with an alternating curvature to the air core modes. The fabrication process of NCHCFs and several potential applications of NCHCFs in medicine, sensing and high power delivery are discussed.

Pryamikov, Andrey D.

2014-03-01

33

Two Approaches in One for a Quick and Efficient Design of Low Area Custom Microprocessor Cores  

E-print Network

- This paper presents a methodology encapsulating the Hardware-Software Co- Design and the Top-Down Approach, was created in a top-down design style using VHDL models for the hardware part. A set of base algorithms electronics. The design process of the core had to meet the following specification requirements: · the core

Stefanov, Todor Plamenov

34

Two Approaches in One for a Quick and Efficient Design of Low Area Custom Microprocessor Cores  

E-print Network

­ This paper presents a methodology encapsulating the Hardware­Software Co­ Design and the Top­Down Approach, was created in a top­down design style using VHDL models for the hardware part. A set of base algorithms electronics. The design process of the core had to meet the following specification requirements: . the core

Stefanov, Todor Plamenov

35

Core design for use with precision composite reflectors  

NASA Technical Reports Server (NTRS)

A uniformly flexible core, and method for manufacturing the same, is disclosed for use between the face plates of a sandwich structure. The core is made of a plurality of thin corrugated strips, the corrugations being defined by a plurality of peaks and valleys connected to one another by a plurality of diagonal risers. The corrugated strips are orthogonally criss-crossed to form the core. The core is particularly suitable for use with high accuracy spherically curved sandwich structures because undesirable stresses in the curved face plates are minimized due to the uniform flexibility characteristics of the core in both the X and Y directions. The core is self venting because of the open geometry of the corrugations. The core can be made from any suitable composite, metal, or polymer. Thermal expansion problems in sandwich structures may be minimized by making the core from the same composite materials that are selected in the manufacture of the curved face plates because of their low coefficients of thermal expansion. Where the strips are made of a composite material, the core may be constructed by first cutting an already cured corrugated sheet into a plurality of corrugated strips and then secondarily bonding the strips to one another or, alternatively, by lying a plurality of uncured strips orthogonally over one another in a suitable jig and then curing and bonding the entire plurality of strips to one another in a single operation.

Porter, Christopher C. (inventor); Jacoy, Paul J. (inventor); Schmitigal, Wesley P. (inventor)

1992-01-01

36

Conceptual Design of a Modular Island Core Fast Breeder Reactor \\  

Microsoft Academic Search

A metal fueled modular island core sodium cooled fast breeder reactor concept RAPID-M to improve reactor per- formance and proliferation resistance and to accommodate various power requirements has been demonstrated. The essential feature of the RAPID-M concept is that the reactor core consists of integrated fuel assemblies (IFAs) instead of conventional fuel subassemblies. The RAPID concept enables quick and simplified

Mitsuru KAMBE

2002-01-01

37

Development of small, fast reactor core designs using lead-based coolant.  

SciTech Connect

A variety of small (100 MWe) fast reactor core designs are developed, these include compact configurations, long-lived (15-year fuel lifetime) cores, and derated, natural circulation designs. Trade studies are described which identify key core design issues for lead-based coolant systems. Performance parameters and reactivity feedback coefficients are compared for lead-bismuth eutectic (LBE) and sodium-cooled cores of consistent design. The results of these studies indicate that the superior neutron reflection capability of lead alloys reduces the enrichment and burnup swing compared to conventional sodium-cooled systems; however, the discharge fluence is significantly increased. The size requirement for long-lived systems is constrained by reactivity loss considerations, not fuel burnup or fluence limits. The derated lead-alloy cooled natural circulation cores require a core volume roughly eight times greater than conventional compact systems. In general, reactivity coefficients important for passive safety performance are less favorable for the larger, derated configurations.

Cahalan, J. E.; Hill, R. N.; Khalil, H. S.; Wade, D. C.

1999-06-11

38

Test vector decompression via cyclical scan chains and its application to testing core-based designs  

Microsoft Academic Search

A novel test vector compressioddecompression technique is proposed for reducing the amount of test data that must be stored on a tester and transferred to each core when testing a core-based design. A small amount of on-chip circuitry is used to reduce both the test storage and test time required for testing a core-based design. The fully specified test vectors

Abhijit Jas; Nur A. Touba

1998-01-01

39

Direct access test scheme-design of block and core cells for embedded ASICs  

Microsoft Academic Search

Intel requires the use of a direct-access test scheme in embedded-core or block-based ASIC (application-specific integrated-circuit) designs. This scheme provides for separate testing of individual block or core cells using proven test vectors. The authors discuss the design modifications for block cells with low pin counts, user application blocks, and large cores with high pin counts. The implementation and verification

V. Immaneni; S. Raman

1990-01-01

40

DESIGN AND OPERATION OF A WIRELINE RETRIEVABLE MOTOR DRIVEN CORE BARREL  

E-print Network

DESIGN AND OPERATION OF A WIRELINE RETRIEVABLE MOTOR DRIVEN CORE BARREL OCEAN DRILLING PROGRAM) Ocean Research Institute of the University of Tokyo (Japan) National Science Foundation (United States of a Motor-Driven Core Barrel 9 1.0 Introduction 9 1.1 Conceptual Design 9 Chapter 2: NCB1: Development, Land

41

Chapter 5 Embedded Core Test Fundamentals 1 Design-for-Test for Digital IC's and Embedded Core Systems Alfred L. Crouch  

E-print Network

Systems Alfred L. Crouch © 1999 Prentice Hall, All Rights Reserved Chapter 5 Embedded Core Test Test Fundamentals 3 Design-for-Test for Digital IC's and Embedded Core Systems Alfred L. Crouch © 1999 Design-for-Test for Digital IC's and Embedded Core Systems Alfred L. Crouch © 1999 Prentice Hall, All

Greenwood, Garrison W.

42

High-burnup core design using minor actinide-containing metal fuel  

SciTech Connect

A neutronic design study of metal fuel fast reactor (FR) cores is conducted on the basis of an innovative fuel design concept to achieve an extremely high burnup and realize an efficient fuel cycle system. Since it is expected that the burnup reactivity swing will become extremely large in an unprecedented high burnup core, minor actinides (MAs) from light water reactors (LWRs) are added to fresh fuel to improve the core internal conversion. Core neutronic analysis revealed that high burnups of about 200 MWd/kg for a small-scale core and about 300 MWd/kg for a large-scale core can be attained while suppressing the burnup reactivity swing to almost the same level as that of conventional cores with normal burnup. An actinide burnup analysis has shown that the MA consumption ratio is improved to about 60% and that the accumulated MAs originating from LWRs can be efficiently consumed by the high-burnup metal fuel FR. (authors)

Ohta, Hirokazu; Ogata, Takanari [Central Research Institute of Electric Power Industry, 2-11-1, Iwado Kita. Komae-shi, Tokyo 201-8511 (Japan); Obara, T. [Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8550 (Japan)

2013-07-01

43

CTSI Quantitative Methods Pilot Program The Design, Biostatistics and Epidemiology (DBE) Core, the Pilot Core, and the Novel  

E-print Network

1 CTSI Quantitative Methods Pilot Program The Design, Biostatistics and Epidemiology (DBE) Core, a quantitative methods researcher is an investigator with a background in statistics, biostatistics, epidemiology the career development of junior investigators in the fields of statistics, biostatistics, and epidemiology

Sibille, Etienne

44

Modified Anchor Shaped Post Core Design for Primary Anterior Teeth  

PubMed Central

Restoring severely damaged primary anterior teeth is challenging to pedodontist. Many materials are tried as a post core but each one of them has its own drawbacks. This a case report describing a technique to restore severely damaged primary anterior teeth with a modified anchor shaped post. This technique is not only simple and inexpensive but also produces better retention. PMID:25379294

Rajesh, R.; Baroudi, Kusai; Reddy, K. Bala Kasi; Praveen, B. H.; Kumar, V. Sumanth; Amit, S.

2014-01-01

45

Core Curriculum Analysis: A Tool for Educational Design  

ERIC Educational Resources Information Center

This paper examines the outcome of a dimensional core curriculum analysis. The analysis process was an integral part of an educational development project, which aimed to compact and clarify the curricula of the degree programmes. The task was also in line with the harmonising of the degree structures as part of the Bologna process within higher…

Levander, Lena M.; Mikkola, Minna

2009-01-01

46

Three-dimensional flux distributions in transformer cores as a function of package design  

Microsoft Academic Search

In spite of extensive optimizations of transformer core designs, investigations of full sized cores showed distinct inhomogeneities of flux density B. Limbs showed discontinuous variations of B in peripheral packages and minima of B in thick central ones. The latter are not caused by global eddy currents but rather by localized flux components ?z normal to the sheet plane. Attempts

H. Pfuetzner; C. Bengtsson; T. Booth; F. Loffler; K. Gramm

1994-01-01

47

Mechanical design of core components for a high performance light water reactor with a three pass core  

SciTech Connect

Nuclear reactors using supercritical water as coolant can achieve more than 500 deg. C core outlet temperature, if the coolant is heated up in three steps with intermediate mixing to avoid hot streaks. This method reduces the peak cladding temperatures significantly compared with a single heat up. The paper presents an innovative mechanical design which has been developed recently for such a High Performance Light Water Reactor. The core is built with square assemblies of 40 fuel pins each, using wire wraps as grid spacers. Nine of these assemblies are combined to a cluster having a common head piece and a common foot piece. A downward flow of additional moderator water, separated from the coolant, is provided in gaps between the assemblies and in a water box inside each assembly. The cluster head and foot pieces and mixing chambers, which are key components for this design, are explained in detail. (authors)

Fischer, Kai [EnBW Kernkraft GmbH, Kernkraftwerk Philippsburg, D-76661 Philippsburg (Germany); Schneider, Tobias; Redon, Thomas [University of Karlsruhe, 76133 Karlsruhe (Germany); Schulenberg, Thomas; Starflinger, Joerg [Forschungszentrum Karlsruhe, Institute for Nuclear and Energy Technologies, 76021 Karlsruhe (Germany)

2007-07-01

48

76 FR 14825 - Core Principles and Other Requirements for Designated Contact Markets  

Federal Register 2010, 2011, 2012, 2013, 2014

...3038-AD09 Core Principles and Other Requirements for Designated Contact Markets AGENCY: Commodity Futures Trading Commission. ACTION...site at http://www.cftc.gov. FOR FURTHER INFORMATION CONTACT: Nancy Markowitz, Assistant Deputy Director,...

2011-03-18

49

Development of optimized core design and analysis methods for high power density BWRs  

E-print Network

Increasing the economic competitiveness of nuclear energy is vital to its future. Improving the economics of BWRs is the main goal of this work, focusing on designing cores with higher power density, to reduce the BWR ...

Shirvan, Koroush

2013-01-01

50

Design of a novel air-cored permanent magnet linear generator for wave energy conversion  

Microsoft Academic Search

An analytical design optimisation model of a novel air-cored permanent magnet linear generator is developed for wave energy conversion. The aim is to reach a design with dimensions optimised for minimum cost of the active material. The analytical results are verified with finite element analysis and compared to previous studies. The optimised machine shows considerable improvement over previous designs.

Rieghard Vermaak; Maarten J. Kamper

2010-01-01

51

Legal Protection on IP Cores for System-on-Chip Designs  

NASA Astrophysics Data System (ADS)

The current semiconductor industry has shifted from vertical integrated model to horizontal specialization model in term of integrated circuit manufacturing. In this circumstance, IP cores as solutions for System-on-Chip (SoC) have become increasingly important for semiconductor business. This paper examines to what extent IP cores of SoC effectively can be protected by current intellectual property system including integrated circuit layout design law, patent law, design law, copyright law and unfair competition prevention act.

Kinoshita, Takahiko

52

Design and Evaluation of an Enhanced In-Vessel Core Catcher  

SciTech Connect

An enhanced in-vessel core catcher is being designed and evaluated as part of a joint United States (U.S.) - Korean International Nuclear Engineering Research Initiative (INERI) investigating methods to insure In-Vessel Retention (IVR) of core materials that may relocate under severe accident conditions in advanced reactors. To reduce cost and simplify manufacture and installation, this new core catcher design consists of several interlocking sections that are machined to fit together when inserted into the lower head. If needed, the core catcher can be manufactured with holes to accommodate lower head penetrations. Each section of the core catcher consists of two material layers with an option to add a third layer (if deemed necessary): a base material, which has the capability to support and contain the mass of core materials that may relocate during a severe accident; an oxide coating material on top of the base material, which resists interactions with high-temperature core materials; and an optional coating on the bottom side of the base material to prevent any potential oxidation of the base material during the lifetime of the reactor. This paper summarizes the status of core catcher design and evaluation efforts, including analyses, materials interaction tests, and prototypic testing efforts.

Joy L. Rempe

2004-06-01

53

LMR design concepts for transuranic management in low sodium void worth cores  

SciTech Connect

The fuel cycle processing techniques and hard neuron spectrum of the Integral Fast Reactor (IFR) metal fuel cycle have favorable characteristics for the management of transuranics; and the wide range of breeding characteristics available in metal fuelled cores provides for flexibility in transuranic management strategy. Previous studies indicate that most design options which decrease the breeding ratio also show a decrease in sodium void worth; therefore, low void worths are achievable in transuranic burning (low breeding ratio) core designs. This paper describes numerous trade studies assessing various design options for a low void worth transuranic burner core. A flat annular core design appears to be a promising concept; the high leakage geometry yields a low breeding ratio and small sodium void worth. To allow flexibility in breeding characteristics, alternate design options which achieve fissile self-sufficiency are also evaluated. A self-sufficient core design which is interchangeable with the burner core and maintains a low sodium void worth is developed. 13 refs., 1 fig., 4 tabs.

Hill, R.N.

1991-01-01

54

Multipurpose Advanced 'inherently' Safe Reactor (MARS): Core design studies  

SciTech Connect

In the year 2005, in collaboration with CEA, the University of Rome 'La Sapienza' investigated a new core model with the aim at increasing the performances of the reference one, by extending the burn-up to 60 GWD/t in the case of multi-loading strategy and investigating the characteristics and limitations of a 'once-through' option, in order to enhance the proliferation resistance. In the first part of this paper, the objectives of this study and the methods of calculation are briefly described, while in the second part the calculation results are presented. (authors)

Golfier, H. [DM2S/SERMA/LCA, CEA Saclay, 91191 Gif-sur-Yvette Cedex (France); Caterino, S. [Univ. of Rome La Sapienza, Dept. of Nuclear Engineering and Energy Conversion, Corso Vittorio Emanuele II, 244 00186 Rome (Italy); Poinot, C.; Delpech, M.; Mignot, G. [DM2S/SERMA/LCA, CEA Saclay, 91191 Gif-sur-Yvette Cedex (France); Naviglio, A.; Gandini, A. [Univ. of Rome La Sapienza, Dept. of Nuclear Engineering and Energy Conversion, Corso Vittorio Emanuele II, 244 00186 Rome (Italy)

2006-07-01

55

McCARD for Neutronics Design and Analysis of Research Reactor Cores  

NASA Astrophysics Data System (ADS)

McCARD is a Monte Carlo (MC) neutron-photon transport simulation code developed exclusively for the neutronics design and analysis of nuclear reactor cores. McCARD is equipped with the hierarchical modeling and scripting functions, the CAD-based geometry processing module, the adjoint-weighted kinetics parameter and source multiplication factor estimation modules as well as the burnup analysis capability for the neutronics design and analysis of both research and power reactor cores. This paper highlights applicability of McCARD for the research reactor core neutronics analysis, as demonstrated for Kyoto University Critical Assembly, HANARO, and YALINA.

Shim, Hyung Jin; Park, Ho Jin; Kwon, Soonwoo; Seo, Geon Ho; Hyo Kim, Chang

2014-06-01

56

Reactor core design of Gas Turbine High Temperature Reactor 300  

Microsoft Academic Search

Japan Atomic Energy Research Institute (JAERI) has been designing Japan’s original gas turbine high temperature reactor, Gas Turbine High Temperature Reactor 300 (GTHTR300). The greatly simplified design based on salient features of the High Temperature Gas-cooled Reactor (HTGR) with a closed helium gas turbine enables the GTHTR300 a highly efficient and economically competitive reactor to be deployed in early 2010s.

Kazuhiko Kunitomi; Shoji Katanishi; Shoji Takada; Xing Yan; Nobumasa Tsuji

2004-01-01

57

Modified Y-TZP Core Design Improves All-ceramic Crown Reliability  

PubMed Central

This study tested the hypothesis that all-ceramic core-veneer system crown reliability is improved by modification of the core design. We modeled a tooth preparation by reducing the height of proximal walls by 1.5 mm and the occlusal surface by 2.0 mm. The CAD-based tooth preparation was replicated and positioned in a dental articulator for core and veneer fabrication. Standard (0.5 mm uniform thickness) and modified (2.5 mm height lingual and proximal cervical areas) core designs were produced, followed by the application of veneer porcelain for a total thickness of 1.5 mm. The crowns were cemented to 30-day-aged composite dies and were either single-load-to-failure or step-stress-accelerated fatigue-tested. Use of level probability plots showed significantly higher reliability for the modified core design group. The fatigue fracture modes were veneer chipping not exposing the core for the standard group, and exposing the veneer core interface for the modified group. PMID:21057036

Silva, N.R.F.A.; Bonfante, E.A.; Rafferty, B.T.; Zavanelli, R.A.; Rekow, E.D.; Thompson, V.P.; Coelho, P.G.

2011-01-01

58

Design methodology of ultra low-power MPEG4 codec core exploiting voltage scaling techniques  

Microsoft Academic Search

This paper describes a fully automated low-power design methodology in which three different voltage-scaling techniques are combined together. Supply voltage is scaled globally, selectively, and adaptively while keeping the performance. This methodology enabled us to design an MPEG4 codec core with 58% less power than the original in three week turn-around-time.

Kimiyoshi Usami; Mutsunori Igarashi; Takashi Ishikawa; Masahiro Kanazawa; Masafumi Takahashi; Mototsugu Hamada; Hideho Arakida; Toshihiro Terazawa; Tadahiro Kuroda

1998-01-01

59

Core-Selecting Combinatorial Auction Design for Secondary Spectrum Markets  

E-print Network

and spatial domains: large chunks of spectrum remain idle while non- licensed new users are unable to access), with monetary remuneration in return. In such a secondary spectrum market, auctions are a natural mechanism design is to achieve efficiency, i.e., to maximize social welfare, the aggregated `happiness' of everyone

Li, Baochun

60

Increasing Sequence Diversity with Flexible Backbone Protein Design: The Complete Redesign of a Protein Hydrophobic Core  

SciTech Connect

Protein design tests our understanding of protein stability and structure. Successful design methods should allow the exploration of sequence space not found in nature. However, when redesigning naturally occurring protein structures, most fixed backbone design algorithms return amino acid sequences that share strong sequence identity with wild-type sequences, especially in the protein core. This behavior places a restriction on functional space that can be explored and is not consistent with observations from nature, where sequences of low identity have similar structures. Here, we allow backbone flexibility during design to mutate every position in the core (38 residues) of a four-helix bundle protein. Only small perturbations to the backbone, 12 {angstrom}, were needed to entirely mutate the core. The redesigned protein, DRNN, is exceptionally stable (melting point >140C). An NMR and X-ray crystal structure show that the side chains and backbone were accurately modeled (all-atom RMSD = 1.3 {angstrom}).

Murphy, Grant S.; Mills, Jeffrey L.; Miley, Michael J.; Machius, Mischa; Szyperski, Thomas; Kuhlman, Brian (UNC); (SUNYB)

2012-08-10

61

Design and fabrication of a novel core-suspended optic fiber for distributed gas sensor  

NASA Astrophysics Data System (ADS)

We designed a novel core-suspended capillary fiber that the core was suspended in the air hole and close to the inner surface of the capillary, and experimentally demonstrated its fabrication technology. In addition, a method for linking a single mode fiber and a core-suspended fiber was proposed based on splicing and tapering at the fusion point between the two fibers. By combining with the optical time domain reflectometer technology, we constructed a distributed gas sensor system to monitor greenhouse gas based on this novel fiber.

Zhang, Tao; Ma, Lijia; Bai, Hongbo; Tong, Chengguo; Dai, Qiang; Kang, Chong; Yuan, Libo

2014-06-01

62

Effective Domain Partitioning for Multi-Clock Domain IP Core Wrapper Design under Power Constraints  

Microsoft Academic Search

The rapid advancement of VLSI technology has made it possible for chip designers and manufacturers to embed the components of a whole system onto a single chip, called System-on-Chip or SoC. SoCs make use of pre-designed modules, called IP-cores, which provide faster design time and quicker time-to-market. Furthermore, SoCs that operate at multiple clock domains and very low power requirements

Thomas Edison Yu; Tomokazu Yoneda; Danella Zhao; Hideo Fujiwara

2008-01-01

63

An Optimized Design of MCU in CPU Soft-core Based on the FPGA  

Microsoft Academic Search

Through the discussion of the structure and the design process about micro-programmed control unit (MCU) in CPU soft-core. An optimized design method of next-address shift logic in MCU is presented in this paper by designing instruction operating code and arranging microinstructions storage. Some of codes using Verilog HDL are given. Simulation result indicate that this method is practical and has

Xing Yuhua; Wang Ru

2007-01-01

64

Design and pilot evaluation of the RAH-66 Comanche Core AFCS  

NASA Technical Reports Server (NTRS)

This paper addresses the design and pilot evaluation of the Core Automatic Flight Control System (AFCS) for the Reconnaissance/Attack Helicopter (RAH-66) Comanche. During the period from November 1991 through February 1992, the RAH-66 Comanche control laws were evaluated through a structured pilot acceptance test using a motion base simulator. Design requirements, descriptions of the control law design, and handling qualities data collected from ADS-33 maneuvers are presented.

Fogler, Donald L., Jr.; Keller, James F.

1993-01-01

65

Design and realization of the IP control core in field controllers for LAMOST spectroscopes  

NASA Astrophysics Data System (ADS)

The China-made telescope, LAMOST, consists of 16 spectroscopes to detect stellar spectra via 4000 optical fibers. In each spectroscope, many movable parts work in phase. Those parts are real-time controlled and managed by field controllers based on FPGA. This paper mainly introduces how to use DSP Builder module library in MATLAB / Simulink to construct the IP control core on FPGA chip. This method can also be used to design the control core of PID arithmetic, to carry out arithmetic simulation and generate VHDL language file, as well as to integrate it into SOPC developing environment so as to repeatedly use. In this way, the design period of the control system may be shortened and design process simplified. Finally due to the reversibility and programmability of the IP control core ,a system on a chip for field controllers of spectroscope is realized, which meets astronomical control requirements, providing an effective scheme for embedded system in astronomical instrument applications.

Wang, Jianing; Han, Zhongyi; Zeng, Yizhong; Dai, Songxin; Hu, Zhongwen; Zhu, Yongtian; Wang, Lei; Hou, Yonghui

2010-07-01

66

Core Noise: Implications of Emerging N+3 Designs and Acoustic Technology Needs  

NASA Technical Reports Server (NTRS)

This presentation is a summary of the core-noise implications of NASA's primary N+3 aircraft concepts. These concepts are the MIT/P&W D8.5 Double Bubble design, the Boeing/GE SUGAR Volt hybrid gas-turbine/electric engine concept, the NASA N3-X Turboelectric Distributed Propulsion aircraft, and the NASA TBW-XN Truss-Braced Wing concept. The first two are future concepts for the Boeing 737/Airbus A320 US transcontinental mission of 180 passengers and a maximum range of 3000 nm. The last two are future concepts for the Boeing 777 transpacific mission of 350 passengers and a 7500 nm range. Sections of the presentation cover: turbofan design trends on the N+1.5 time frame and the already emerging importance of core noise; the NASA N+3 concepts and associated core-noise challenges; the historical trends for the engine bypass ratio (BPR), overall pressure ratio (OPR), and combustor exit temperature; and brief discussion of a noise research roadmap being developed to address the core-noise challenges identified for the N+3 concepts. The N+3 conceptual aircraft have (i) ultra-high bypass ratios, in the rage of 18 - 30, accomplished by either having a small-size, high-power-density core, an hybrid design which allows for an increased fan size, or by utilizing a turboelectric distributed propulsion design; and (ii) very high OPR in the 50 - 70 range. These trends will elevate the overall importance of turbomachinery core noise. The N+3 conceptual designs specify the need for the development and application of advanced liners and passive and active control strategies to reduce the core noise. Current engineering prediction of core noise uses semi-empirical methods based on older turbofan engines, with (at best) updates for more recent designs. The models have not seen the same level of development and maturity as those for fan and jet noise and are grossly inadequate for the designs considered for the N+3 time frame. An aggressive program for the development of updated noise prediction tools for integrated core assemblies as well as and strategies for noise reduction and control is needed in order to meet the NASA N+3 noise goals. The NASA Fundamental Aeronautics Program has the principal objective of overcoming today's national challenges in air transportation. The SFW Reduced-Perceived-Noise Technical Challenge aims to develop concepts and technologies to dramatically reduce the perceived aircraft noise outside of airport boundaries. This reduction of aircraft noise is critical to enabling the anticipated large increase in future air traffic.

Hultgren, Lennart S.

2011-01-01

67

Baseline Design Compliance Matrix for the Rotary Mode Core Sampling System  

SciTech Connect

The purpose of the design compliance matrix (DCM) is to provide a single-source document of all design requirements associated with the fifteen subsystems that make up the rotary mode core sampling (RMCS) system. It is intended to be the baseline requirement document for the RMCS system and to be used in governing all future design and design verification activities associated with it. This document is the DCM for the RMCS system used on Hanford single-shell radioactive waste storage tanks. This includes the Exhauster System, Rotary Mode Core Sample Trucks, Universal Sampling System, Diesel Generator System, Distribution Trailer, X-Ray Cart System, Breathing Air Compressor, Nitrogen Supply Trailer, Casks and Cask Truck, Service Trailer, Core Sampling Riser Equipment, Core Sampling Support Trucks, Foot Clamp, Ramps and Platforms and Purged Camera System. Excluded items are tools such as light plants and light stands. Other items such as the breather inlet filter are covered by a different design baseline. In this case, the inlet breather filter is covered by the Tank Farms Design Compliance Matrix.

LECHELT, J.A.

2000-10-17

68

Designing with advanced composites; Report on the European Core Conference, 1st, Zurich, Switzerland, Oct. 20, 21, 1988, Conference Papers  

SciTech Connect

The present conference discusses the development history of sandwich panel construction, production methods and quality assurance for Nomex sandwich panel core papers, the manufacture of honeycomb cores, state-of-the-art design methods for honeycomb-core panels, the Airbus A320 airliner's CFRP rudder structure, and the design tradeoffs encountered in honeycomb-core structures' design. Also discussed are sandwich-construction aircraft cabin interiors meeting new FAA regulations, the use of Nomex honeycomb cores in composite structures, a low-cost manufacturing technique for sandwich structures, and the Starship sandwich panel-incorporating airframe primary structure.

Not Available

1988-01-01

69

PWR core design, neutronics evaluation and fuel cycle analysis for thorium-uranium breeding recycle  

SciTech Connect

This paper was focused on core design, neutronics evaluation and fuel cycle analysis for Thorium-Uranium Breeding Recycle in current PWRs, without any major change to the fuel lattice and the core internals, but substituting the UOX pellet with Thorium-based pellet. The fuel cycle analysis indicates that Thorium-Uranium Breeding Recycle is technically feasible in current PWRs. A 4-loop, 193-assembly PWR core utilizing 17 x 17 fuel assemblies (FAs) was taken as the model core. Two mixed cores were investigated respectively loaded with mixed reactor grade Plutonium-Thorium (PuThOX) FAs and mixed reactor grade {sup 233}U-Thorium (U{sub 3}ThOX) FAs on the basis of reference full Uranium oxide (UOX) equilibrium-cycle core. The UOX/PuThOX mixed core consists of 121 UOX FAs and 72 PuThOX FAs. The reactor grade {sup 233}U extracted from burnt PuThOX fuel was used to fabrication of U{sub 3}ThOX for starting Thorium-. Uranium breeding recycle. In UOX/U{sub 3}ThOX mixed core, the well designed U{sub 3}ThOX FAs with 1.94 w/o fissile uranium (mainly {sup 233}U) were located on the periphery of core as a blanket region. U{sub 3}ThOX FAs remained in-core for 6 cycles with the discharged burnup achieving 28 GWD/tHM. Compared with initially loading, the fissile material inventory in U{sub 3}ThOX fuel has increased by 7% via 1-year cooling after discharge. 157 UOX fuel assemblies were located in the inner of UOX/U{sub 3}ThOX mixed core refueling with 64 FAs at each cycle. The designed UOX/PuThOX and UOX/U{sub 3}ThOX mixed core satisfied related nuclear design criteria. The full core performance analyses have shown that mixed core with PuThOX loading has similar impacts as MOX on several neutronic characteristic parameters, such as reduced differential boron worth, higher critical boron concentration, more negative moderator temperature coefficient, reduced control rod worth, reduced shutdown margin, etc.; while mixed core with U{sub 3}ThOX loading on the periphery of core has no visible impacts on neutronic characteristics compared with reference full UOX core. The fuel cycle analysis has shown that {sup 233}U mono-recycling with U{sub 3}ThOX fuel could save 13% of natural uranium resource compared with UOX once through fuel cycle, slightly more than that of Plutonium single-recycling with MOX fuel. If {sup 233}U multi-recycling with U{sub 3}ThOX fuel is implemented, more natural uranium resource would be saved. (authors)

Bi, G.; Liu, C.; Si, S. [Shanghai Nuclear Engineering Research and Design Inst., No. 29, Hongcao Road, Shanghai, 200233 (China)

2012-07-01

70

The Design and Performance of IceCube DeepCore  

NASA Technical Reports Server (NTRS)

The IceCube neutrino observatory in operation at the South Pole, Antarctica, comprises three distinct components: a large buried array for ultrahigh energy neutrino detection, a surface air shower array, and a new buried component called DeepCore. DeepCore was designed to lower the IceCube neutrino energy threshold by over an order of magnitude, to energies as low as about 10 GeV. DeepCore is situated primarily 2100 m below the surface of the icecap at the South Pole, at the bottom center of the existing IceCube array, and began taking pbysics data in May 2010. Its location takes advantage of the exceptionally clear ice at those depths and allows it to use the surrounding IceCube detector as a highly efficient active veto against the principal background of downward-going muons produced in cosmic-ray air showers. DeepCore has a module density roughly five times higher than that of the standard IceCube array, and uses photomultiplier tubes with a new photocathode featuring a quantum efficiency about 35% higher than standard IceCube PMTs. Taken together, these features of DeepCore will increase IceCube's sensitivity to neutrinos from WIMP dark matter annihilations, atmospheric neutrino oscillations, galactic supernova neutrinos, and point sources of neutrinos in the northern and southern skies. In this paper we describe the design and initial performance of DeepCore.

Stamatikos, M.

2012-01-01

71

Fuel Design and Core Layout for a Gas-Cooled Fast Reactor  

SciTech Connect

The gas-cooled fast reactor (GCFR) is regarded as the primary candidate for a future sustainable nuclear power system. In this paper a general core layout is presented for a 2400-MW(thermal) GCFR. Two fuel elements are discussed: a TRISO-based coated particle and the innovative hollow sphere concept. Sustainability calls for recycling of all minor actinides (MAs) in the core and a breeding gain close to unity. A fuel cycle is designed allowing operation over a long period, requiring refueling with {sup 238}U only. The evolution of nuclides in the GCFR core is calculated using the SCALE system (one-dimensional and three-dimensional). Calculations were done over multiple irradiation cycles including reprocessing. The result is that it is possible to design a fuel and GCFR core with a breeding gain around unity, with recycling of all MAs from cycle to cycle. The burnup reactivity swing is small, improving safety. After several fuel batches an equilibrium core is reached. MA loading in the core remains limited, and the fuel temperature coefficient is always negative.

Rooijen, W.F.G. van; Kloosterman, J.L.; Hagen, T.H.J.J. van der; Dam, H. van [Delft University of Technology (Netherlands)

2005-09-15

72

A multi-group Monte Carlo core analysis method and its application in SCWR design  

SciTech Connect

Complex geometry and spectrum have been the characteristics of many newly developed nuclear energy systems, so the suitability and precision of the traditional deterministic codes are doubtable while being applied to simulate these systems. On the contrary, the Monte Carlo method has the inherent advantages of dealing with complex geometry and spectrum. The main disadvantage of Monte Carlo method is that it takes long time to get reliable results, so the efficiency is too low for the ordinary core designs. A new Monte Carlo core analysis scheme is developed, aimed to increase the calculation efficiency. It is finished in two steps: Firstly, the assembly level simulation is performed by continuous energy Monte Carlo method, which is suitable for any geometry and spectrum configuration, and the assembly multi-group constants are tallied at the same time; Secondly, the core level calculation is performed by multi-group Monte Carlo method, using the assembly group constants generated in the first step. Compared with the heterogeneous Monte Carlo calculations of the whole core, this two-step scheme is more efficient, and the precision is acceptable for the preliminary analysis of novel nuclear systems. Using this core analysis scheme, a SCWR core was designed based on a new SCWR assembly design. The core output is about 1,100 MWe, and a cycle length of about 550 EFPDs can be achieved with 3-batch refueling pattern. The average and maximum discharge burn-up are about 53.5 and 60.9 MWD/kgU respectively. (authors)

Zhang, P.; Wang, K.; Yu, G. [Dept. of Engineering Physics, Tsinghua Univ., Beijing, 100084 (China)

2012-07-01

73

Use of Solid Hydride Fuel for Improved long-Life LWR Core Designs  

SciTech Connect

The primary objective of this project was to assess the feasibility of improving the performance of PWR and BWR cores by using solid hydride fuels instead of the commonly used oxide fuel. The primary measure of performance considered is the bus-bar cost of electricity (COE). Additional performance measures considered are safety, fuel bundle design simplicity – in particular for BWR’s, and plutonium incineration capability. It was found that hydride fuel can safely operate in PWR’s and BWR’s without restricting the linear heat generation rate of these reactors relative to that attainable with oxide fuel. A couple of promising applications of hydride fuel in PWR’s and BWR’s were identified: (1) Eliminating dedicated water moderator volumes in BWR cores thus enabling to significantly increase the cooled fuel rods surface area as well as the coolant flow cross section area in a given volume fuel bundle while significantly reducing the heterogeneity of BWR fuel bundles thus achieving flatter pin-by-pin power distribution. The net result is a possibility to significantly increase the core power density – on the order of 30% and, possibly, more, while greatly simplifying the fuel bundle design. Implementation of the above modifications is, though, not straightforward; it requires a design of completely different control system that could probably be implemented only in newly designed plants. It also requires increasing the coolant pressure drop across the core. (2) Recycling plutonium in PWR’s more effectively than is possible with oxide fuel by virtue of a couple of unique features of hydride fuel – reduced inventory of U-238 and increased inventory of hydrogen. As a result, the hydride fuelled core achieves nearly double the average discharge burnup and the fraction of the loaded Pu it incinerates in one pass is double that of the MOX fuel. The fissile fraction of the Pu in the discharged hydride fuel is only ~2/3 that of the MOX fuel and the discharged hydride fuel is more proliferation resistant. Preliminary feasibility assessment indicates that by replacing some of the ZrH1.6 by ThH2 it will be possible to further improve the plutonium incineration capability of PWR’s. Other possibly promising applications of hydride fuel were identified but not evaluated in this work. A number of promising oxide fueled PWR core designs were also found as spin-offs of this study: (1) The optimal oxide fueled PWR core design features smaller fuel rod diameter of D=6.5 mm and a larger pitch-to-diameter ratio of P/D=1.39 than presently practiced by industry – 9.5mm and 1.326. This optimal design can provide a 30% increase in the power density and a 24% reduction in the cost of electricity (COE) provided the PWR could be designed to have the coolant pressure drop across the core increased from the reference 29 psia to 60 psia. (2) Using wire wrapped oxide fuel rods in hexagonal fuel assemblies it is possible to design PWR cores to operate at 54% higher power density than the reference PWR design that uses grid spacers and a square lattice, provided 60 psia coolant pressure drop across the core could be accommodated. Uprating existing PWR’s to use such cores could result in 40% reduction in the COE. The optimal lattice geometry is D = 8.08 mm and P/D = 1.41. The most notable advantages of wire wraps over grid spacers are their significant lower pressure drop, higher critical heat flux and improved vibrations characteristics.

Greenspan, E

2006-04-30

74

The SNL100-02 blade : advanced core material design studies for the Sandia 100-meter blade.  

SciTech Connect

A series of design studies are performed to investigate the effects of advanced core materials and a new core material strategy on blade weight and performance for large blades using the Sandia 100-meter blade designs as a starting point. The initial core material design studies were based on the SNL100-01 100- meter carbon spar design. Advanced core material with improved performance to weight was investigated with the goal to reduce core material content in the design and reduce blade weight. A secondary element of the core study was to evaluate the suitability of core materials from natural, regrowable sources such as balsa and recyclable foam materials. The new core strategy for the SNL100-02 design resulted in a design mass of 59 tons, which is a 20% reduction from the most recent SNL100-01 carbon spar design and over 48% reduction from the initial SNL100-00 all-glass baseline blade. This document provides a description of the final SNL100-02 design, includes a description of the major design modifications, and summarizes the pertinent blade design information. This document is also intended to be a companion document to the distribution of the NuMAD blade model files for SNL100-02 that are made publicly available.

Griffith, Daniel

2013-11-01

75

Using Domain Partitioning in Wrapper Design for IP Cores Under Power Constraints  

Microsoft Academic Search

This paper presents a novel design method for power-aware test wrappers targeting embedded cores with multiple clock domains. We show that effective partitioning of clock domains combined with bandwidth conversion and gated-clocks would yield shorter test times due to greater flexibility when determining optimal test schedules especially under tight power constraints

Thomas Edison Yu; Tomokazu Yoneda; Danella Zhao; Hideo Fujiwara

2007-01-01

76

Post-silicon Debugging for Multi-core Designs Valeria Bertacco  

E-print Network

Post-silicon Debugging for Multi-core Designs Valeria Bertacco Dept. of Electrical Engineering in released silicon are growing in number due to the increasing complexity of modern processor de- signs. This deteriorating situation is causing a growing portion of the validation effort to shift to post-silicon, when

Bertacco, Valeria

77

AMPLIFIER DESIGN IMPLEMENTING HOLLOW-CORE PHOTONIC BANDGAP FIBER FOR FIBER-LASER BASED INFRARED  

E-print Network

AMPLIFIER DESIGN IMPLEMENTING HOLLOW-CORE PHOTONIC BANDGAP FIBER FOR FIBER-LASER BASED INFRARED-doped fiber lasers typically require an external amplifier since the pulses directly from the laser have Mode-locked erbium-doped fiber lasers produce the ideal frequency comb for infrared optical frequency

Washburn, Brian

78

AMPLIFIER DESIGN IMPLEMENTING HOLLOW-CORE PHOTONIC BANDGAP FIBER FOR FIBER-LASER BASED  

E-print Network

AMPLIFIER DESIGN IMPLEMENTING HOLLOW-CORE PHOTONIC BANDGAP FIBER FOR FIBER-LASER BASED INFRARED-locked erbium-doped fiber lasers typically require an external amplifier since the pulses directly from signal to locking electronics Amplifier HNLF Mode-locked fiber laser Amplifier HNLF Mode-locked fiber

Washburn, Brian

79

Coarse-grained parallel genetic algorithm applied to a nuclear reactor core design optimization problem  

Microsoft Academic Search

This work extends the research related to genetic algorithms (GA) in core design optimization problems, which basic investigations were presented in previous work. Here we explore the use of the Island Genetic Algorithm (IGA), a coarse-grained parallel GA model, comparing its performance to that obtained by the application of a traditional non-parallel GA. The optimization problem consists on adjusting several

Cláudio M. N. A. Pereira; Celso M. F. Lapa

2003-01-01

80

Design and Implementation of the National Institute of Environmental Health Sciences Dublin Core Metadata Schema  

Microsoft Academic Search

The National Institute of Environmental Health Sciences (NIEHS) has formed a team to design and implement a Dublin Core-based metadata schema to enhance the public's ability to retrieve pertinent public health information on the organization's Web site. The team decided to use the DC schema because it is a de facto standard and because of its flexibility. With a little

W. Davenport Robertson; Ellen M. Leadem; Jed Dube; Jane Greenberg

2001-01-01

81

Scan chain design for test time reduction in core-based ICs  

Microsoft Academic Search

The size of the test vector set forms a significant factor in the overall production costs of ICs, as it defines the test application time and the required pin memory size of the test equipment. Large core-based ICs often require a very large test vector set for a high test coverage. This paper deals with the design of scan chains

Joep Aerts; Erik Jan Marinissen

1998-01-01

82

Narrative Plus: Designing and Implementing the Common Core State Standards with the Gift Essay  

ERIC Educational Resources Information Center

The authors of this article describe their inquiry into implementation of the writing-focused Common Core State Standards in a co-taught English 9 class in an urban school. They describe instructional moves designed to increase student success with an assignment called the Gift Essay, with particular focus on planning and other organizational…

Chandler-Olcott, Kelly; Zeleznik, John

2013-01-01

83

PicoJava Processor Core 60 0740-7475/00/$10.00 2000 IEEE IEEE Design & Test of Computers  

E-print Network

processing (DSP) processor cores available and used today, like the cores from ARM, LSI Logic, MotorolaPicoJava Processor Core 60 0740-7475/00/$10.00 © 2000 IEEE IEEE Design & Test of Computers Major. Networking applications like network processors, routers on chips and home gateways, portable products like

California at San Diego, University of

84

A new 122 mm electromechanical drill for deep ice-sheet coring (DISC): 3. Control, electrical and electronics design  

Microsoft Academic Search

The deep ice-sheet coring (DISC) drill developed by Ice Coring and Drilling Services under contract to the US National Science Foundation is an electromechanical drill designed to take 122 mm ice cores to depths of 4000 m. Electronic, electrical and control systems are major aspects of the DISC drill. The drill sonde, the down-hole portion of the drill system, requires

Nicolai B. Mortensen; Paul J. Sendelbach; Alexander J. Shturmakov

2007-01-01

85

An optimized design of a dual-core photonic crystal fiber coupler  

NASA Astrophysics Data System (ADS)

An optical fiber coupler is a very important component in realizing all-fiber communication system. The appearance of dual-core photonic crystal fibers (PCFs) has enabled a new method of designing fiber coupler. Directional coupler based on the dual-core PCFs was investigated and shows intriguing properties, e.g., broadband coupling, the shorter coupling length, and polarized-mode coupling. However, the coupling bandwidth is the one of the most key properties due to the wavelength dependent of coupling efficiency for optical fiber coupler. In order to obtain the wavelength flattened response coupler with insensitive to deformation of air holes, in this paper an asymmetry dual-core PCF coupler with depressed-doped core is proposed and its coupling characteristics are also investigated by full-vector beam propagation method (BPM) in detail. The result of simulation shows that the coupling coefficient of 50%+/- 0.5% over a wide wavelength from 1.3?m to 1.7?m. Its coupling length is about 394?m, which is much shorter than that of other dual-core PCF couplers reported in literature. The fluctuation of coupling ratio is smaller than 5% with variation of the coupling length of 10%. We also demonstrate it could be more robust caused from the shorter coupling length. Furthermore, the mode field of the coupler is Gaussian-shape which means that additional insertion loss will not be introduced.

Xu, Feng; Tao, Dashi; Shi, Miaomiao; Jiang, Chao; Zhang, Bo; Shi, Xiaolong; Yu, Benli

2009-11-01

86

Advanced Core Design And Fuel Management For Pebble-Bed Reactors  

SciTech Connect

A method for designing and optimizing recirculating pebble-bed reactor cores is presented. At the heart of the method is a new reactor physics computer code, PEBBED, which accurately and efficiently computes the neutronic and material properties of the asymptotic (equilibrium) fuel cycle. This core state is shown to be unique for a given core geometry, power level, discharge burnup, and fuel circulation policy. Fuel circulation in the pebble-bed can be described in terms of a few well?defined parameters and expressed as a recirculation matrix. The implementation of a few heat?transfer relations suitable for high-temperature gas-cooled reactors allows for the rapid estimation of thermal properties critical for safe operation. Thus, modeling and design optimization of a given pebble-bed core can be performed quickly and efficiently via the manipulation of a limited number key parameters. Automation of the optimization process is achieved by manipulation of these parameters using a genetic algorithm. The end result is an economical, passively safe, proliferation-resistant nuclear power plant.

Hans D. Gougar; Abderrafi M. Ougouag; William K. Terry

2004-10-01

87

An approach for catalyst design in artificial photosynthetic systems: focus on nanosized inorganic cores within proteins.  

PubMed

Some enzymes can be considered as a catalyst having a nanosized inorganic core in a protein matrix. In some cases, the metal oxide or sulfide clusters, which can be considered as cofactors in enzymes, may be recruited for use in other related reactions in artificial photosynthetic systems. In other words, one approach to design efficient and environmentally friendly catalysts in artificial photosynthetic systems for the purpose of utilizing sunlight to generate high energy intermediates or useful material is to select and utilize inorganic cores of enzymes. For example, one of the most important goals in developing artificial photosynthesis is hydrogen production. However, first, it is necessary to find a "super catalyst" for water oxidation, which is the most challenging half reaction of water splitting. There is an efficient system for water oxidation in cyanobacteria, algae, and plants. Published data on the Mn-Ca cluster have provided details on the mechanism and structure of the water oxidizing complex as a Mn-Ca nanosized inorganic core in photosystem II. Progress has been made in introducing Mn-Ca oxides as efficient catalysts for water oxidation in artificial photosynthetic systems. Here, in the interest of designing efficient catalysts for other important reactions in artificial photosynthesis, a few examples of our knowledge of inorganic cores of proteins, and how Nature used them for important reactions, are discussed. PMID:23377954

Najafpour, Mohammad Mahdi

2013-11-01

88

Advanced core design and fuel management for pebble-bed reactors  

NASA Astrophysics Data System (ADS)

A method for designing and optimizing recirculating pebble-bed reactor cores is presented. At the heart of the method is a new reactor physics computer code, PEBBED, which accurately and efficiently computes the neutronic and material properties of the asymptotic (equilibrium) fuel cycle. This core state is shown to be unique for a given core geometry, power level, discharge burnup, and fuel circulation policy. Fuel circulation in the pebble-bed can be described in terms of a few well-defined parameters and expressed as a recirculation matrix. The implementation of a few heat-transfer relations suitable for high-temperature gas-cooled reactors allows for the rapid estimation of thermal properties critical for safe operation. Thus, modeling and design optimization of a given pebble-bed core can be performed quickly and efficiently via the manipulation of a limited number key parameters. Automation of the optimization process is achieved by manipulation of these parameters using a genetic algorithm. The end result is an economical, passively safe, proliferation-resistant nuclear power plant.

Gougar, Hans David

89

Design and Calibration of a High-Precision Density Gauge for Firn and Ice Cores  

NASA Astrophysics Data System (ADS)

The Maine Automated Density Gauge Experiment (MADGE) is a field deployable gamma-ray density gauging instrument designed to provide high resolution (3.3 mm) and high precision (±0.004 g cm-3) density profiles of polar firn and ice cores at a typical throughput of 1.5 m h-1. The resulting density profiles are important in ice sheet mass balance and paleoclimate studies, as well as the modeling electromagnetic wave propagation in firn and ice for remote sensing and ground penetrating radar applications. This study describes the design (optimal gamma-ray energy selection, measurement uncertainty analysis, dead-time corrections) and calibration (mass-attenuation coefficient and absolute density calibrations) of the instrument, and discusses the results of additional experiments to verify the calculated measurement uncertainty. Data collected from firn cores drilled on the recent 2006-2007 U.S. Internation Trans-Antarctic Scientific Expedition are also shown and discussed.

Breton, Daniel; Hamilton, Gordon

2009-10-01

90

Design assumptions and bases for small D-T-fueled Sperical Tokamak (ST) fusion core  

SciTech Connect

Recent progress in defining the assumptions and clarifying the bases for a small D-T-fueled ST fusion core are presented. The paper covers several issues in the physics of ST plasmas, the technology of neutral beam injection, the engineering design configuration, and the center leg material under intense neutron irradiation. This progress was driven by the exciting data from pioneering ST experiments, a heightened interest in proof-of-principle experiments at the MA level in plasma current, and the initiation of the first conceptual design study of the small ST fusion core. The needs recently identified for a restructured fusion energy sciences program have provided a timely impetus for examining the subject of this paper. Our results, though preliminary in nature, strengthen the case for the potential realism and attractiveness of the ST approach.

Peng, Y.K.M.; Galambos, J.D.; Fogarty, P.J. [and others

1996-12-31

91

Energy Efficient Engine integrated core/low spool design and performance report  

NASA Technical Reports Server (NTRS)

The Energy Efficient Engine (E3) is a NASA program to create fuel saving technology for future transport aircraft engines. The E3 technology advancements were demonstrated to operate reliably and achieve goal performance in tests of the Integrated Core/Low Spool vehicle. The first build of this undeveloped technology research engine set a record for low fuel consumption. Its design and detailed test results are herein presented.

Stearns, E. Marshall

1985-01-01

92

System Design for a Nuclear Electric Spacecraft Utilizing Out-of-core Thermionic Conversion  

NASA Technical Reports Server (NTRS)

Basic guidelines are presented for a nuclear space power system which utilizes heat pipes to transport thermal power from a fast nuclear reactor to an out of core thermionic converter array. Design parameters are discussed for the nuclear reactor, heat pipes, thermionic converters, shields (neutron and gamma), waste heat rejection systems, and the electrical bus bar-cable system required to transport the high current/low voltage power to the processing equipment. Dimensions are compatible with shuttle payload bay constraints.

Estabrook, W. C.; Phillips, W. M.; Hsieh, T.

1976-01-01

93

Multi-core Paralleled Design and Analysis for BP Inversion Algorithm of Magnetic Anomalies  

Microsoft Academic Search

(Abstract)In the process of 3-D inversion of gravity and magnetic anomalies for physical properties with large scale data, the BP inversion algorithm produces huge storage and computation requirement. This paper offers an efficient solution based on the principle of storage equivalent and multi-core paralleled design. It mainly includes applying the principle of storage equivalent to the position function of physical

XIA Jun-bao; LI Tao; WANG Qun

2009-01-01

94

Test Planning and Design Space Exploration in a Core-Based Environment  

Microsoft Academic Search

This paper proposes a comprehensive model for testplanning in a core-based environment. The main contributionof this work is the use of several types of TAMs and theconsideration of different optimization factors (area, pinsand test time) during the global TAM and test schedule definition.This expansion of concerns makes possible an efficientyet fine-grained search in the huge design space ofa reuse-based environment.

Erika Cota; Luigi Carro; Marcelo Lubaszewski; Alex Orailoglu

2002-01-01

95

Design manufacture and test of a cryo-stable Offner relay using aluminum foam core optics  

NASA Astrophysics Data System (ADS)

Aluminum foam core optics have the desirable characteristics of being lightweight, cryo-stable, and low cost. The availability of high quality aluminum foam and a bare aluminum super-polishing process have allowed high performance foam core optics made entirely of aluminum to be produced. Mirrors with integral mounts were designed for minimum surface error induced by self-weight deflection, thermal gradients, and mounting stresses. The design of the optics was extensively optimized using Finite Element Analysis (FEA) and Geometric Element Analysis (GEA) to determine the effects of design parameters on mirror performance under the anticipated operating environments. A unique manufacturing process was developed to accommodate the aluminum brazing process used to install the aluminum foam while maintaining dimensional stability. Aluminum foam core optics have the additional advantage of being fabricated from a common aerospace structural material. An Offner relay using all aluminum optics and structure will be manufactured and tested with the goal of demonstrating that an all aluminum optical system can be aligned at room temperature and maintain alignment at cryogenic temperatures due to near zero CTE mismatch between all system components. If successful, an all aluminum Offner relay has potential uses for NGST, specifically in the testing of micro-mirror arrays.

McClelland, Ryan S.; Content, David A.

2001-12-01

96

Lunar in-core thermionic nuclear reactor power system conceptual design  

NASA Technical Reports Server (NTRS)

This paper presents a conceptual design of a lunar in-core thermionic reactor power system. The concept consists of a thermionic reactor located in a lunar excavation with surface mounted waste heat radiators. The system was integrated with a proposed lunar base concept representative of recent NASA Space Exploration Initiative studies. The reference mission is a permanently-inhabited lunar base requiring a 550 kWe, 7 year life central power station. Performance parameters and assumptions were based on the Thermionic Fuel Element (TFE) Verification Program. Five design cases were analyzed ranging from conservative to advanced. The cases were selected to provide sensitivity effects on the achievement of TFE program goals.

Mason, Lee S.; Schmitz, Paul C.; Gallup, Donald R.

1991-01-01

97

Cost-Optimal Design of a 3-Phase Core Type Transformer by Gradient Search Technique  

NASA Astrophysics Data System (ADS)

3-phase core type transformers are extensively used as power and distribution transformers in power system and their cost is a sizable proportion of the total system cost. Therefore they should be designed cost-optimally. The design methodology for reaching cost-optimality has been discussed in details by authors like Ramamoorty. It has also been discussed in brief in some of the text-books of electrical design. The paper gives a method for optimizing design, in presence of constraints specified by the customer and the regulatory authorities, through gradient search technique. The starting point has been chosen within the allowable parameter space the steepest decent path has been followed for convergence. The step length has been judiciously chosen and the program has been maneuvered to avoid local minimal points. The method appears to be best as its convergence is quickest amongst different optimizing techniques.

Basak, R.; Das, A.; Sensarma, A. K.; Sanyal, A. N.

2014-04-01

98

General strategy for designing core-shell nanostructured materials for high-power lithium ion batteries.  

PubMed

Because of its extreme safety and outstanding cycle life, Li(4)Ti(5)O(12) has been regarded as one of the most promising anode materials for next-generation high-power lithium-ion batteries. Nevertheless, Li(4)Ti(5)O(12) suffers from poor electronic conductivity. Here, we develop a novel strategy for the fabrication of Li(4)Ti(5)O(12)/carbon core-shell electrodes using metal oxyacetyl acetonate as titania and single-source carbon. Importantly, this novel approach is simple and general, with which we have successfully produce nanosized particles of an olivine-type LiMPO(4) (M = Fe, Mn, and Co) core with a uniform carbon shell, one of the leading cathode materials for lithium-ion batteries. Metal acetylacetonates first decompose with carbon coating the particles, which is followed by a solid state reaction in the limited reaction area inside the carbon shell to produce the LTO/C (LMPO(4)/C) core-shell nanostructure. The optimum design of the core-shell nanostructures permits fast kinetics for both transported Li(+) ions and electrons, enabling high-power performance. PMID:23092272

Shen, Laifa; Li, Hongsen; Uchaker, Evan; Zhang, Xiaogang; Cao, Guozhong

2012-11-14

99

A 2 Gb\\/s 256*256 CMOS crossbar switch fabric core design using pipelined MUX  

Microsoft Academic Search

In this paper, we present the design of a full-custom 2 Gb\\/s 256*256 crossbar switch fabric core circuit, using TSMC 0.25 ?m CMOS technology. To cope with the high data link rate, conventional approaches use duplicated multiple bit-slices of the switch core to reduce the core delay requirement. However, this increases the area and limits the size of the crossbar

Ting Wu; Chi-Ying Tsui; M. Hamdi

2002-01-01

100

Dosimetric comparison of four new design {sup 103}Pd brachytherapy sources: Optimal design using silver and copper rod cores  

SciTech Connect

Four new brachytherapy sources, IRA1-{sup 103}Pd, IRA2-{sup 103}Pd, IRA3-{sup 103}Pd, and IRA4-{sup 103}Pd, have been developed at Agricultural, Medical, and Industrial Research School and are designed for permanent implant application. With the goal of determining an optimal design for a {sup 103}Pd source, this article compares the dosimetric properties of these sources with reference to the authors' earlier IRA-{sup 103}Pd source. The four new sources differ in end cap configuration and thickness and in the core material, silver or copper, that carries the adsorbed {sup 103}Pd. Dosimetric data derived from the authors' Monte Carlo simulation results are reported in accordance with the updated AAPM Task Group No. 43 report (TG-43U1). For each source, the authors obtained detailed results for the dose rate constant {Lambda}, the radial dose function g(r), the anisotropy function F(r,{theta}), and the anisotropy factor {phi}{sub an}(r). In this study, the optimal source IRA3-{sup 103}Pd provides the most isotropic dose distribution in water with the dose rate constant of 0.678({+-}0.1%) cGy h{sup -1} U{sup -1}. The IRA3-{sup 103}Pd design has a silver rod core combined with thin-wall, concave end caps. Finally, the authors compared the results for their optimal source with published results for those of other source manufacturers.

Hosseini, S. Hamed; Sadeghi, Mahdi; Ataeinia, Vahideh [Agricultural, Medical and Industrial Research School, Nuclear Science and Technology Research Institute, P.O. Box 31485-498, Karaj, Tehran (098)21 (Iran, Islamic Republic of)

2009-07-15

101

Design of a boiling water reactor equilibrium core using thorium-uranium fuel  

SciTech Connect

In this paper the design of a Boiling Water Reactor (BWR) equilibrium core using thorium is presented; a heterogeneous blanket-seed core arrangement concept was adopted. The design was developed in three steps: in the first step two different assemblies were designed based on the integrated blanket-seed concept, they are the blanket-dummy assembly and the blanket-seed assembly. The integrated blanketseed concept comes from the fact that the blanket and the seed rods are located in the same assembly, and are burned-out in a once-through cycle. In the second step, a core design was developed to achieve an equilibrium cycle of 365 effective full power days in a standard BWR with a reload of 104 fuel assemblies designed with an average 235U enrichment of 7.5 w/o in the seed sub-lattice. The main operating parameters, like power, linear heat generation rate and void distributions were obtained as well as the shutdown margin. It was observed that the analyzed parameters behave like those obtained in a standard BWR. The shutdown margin design criterion was fulfilled by addition of a burnable poison region in the assembly. In the third step an in-house code was developed to evaluate the thorium equilibrium core under transient conditions. A stability analysis was also performed. Regarding the stability analysis, five operational states were analyzed; four of them define the traditional instability region corner of the power-flow map and the fifth one is the operational state for the full power condition. The frequency and the boiling length were calculated for each operational state. The frequency of the analyzed operational states was similar to that reported for BWRs; these are close to the unstable region that occurs due to the density wave oscillation phenomena in some nuclear power plants. Four transient analyses were also performed: manual SCRAM, recirculation pumps trip, main steam isolation valves closure and loss of feed water. The results of these transients are similar to those obtained with the traditional UO2 nuclear fuel.

Francois, J-L.; Nunez-Carrera, A.; Espinosa-Paredes, G.; Martin-del-Campo, C.

2004-10-06

102

The 11th International Symposium on Wireless Personal Multimedia Communications (WPMC'08) ENERGY-AWARE UMTS CORE NETWORK DESIGN  

E-print Network

-AWARE UMTS CORE NETWORK DESIGN Luca Chiaraviglio Marco Mellia Fabio Neri Politecnico di Torino Politecnico di propose a novel ap- proach to switch off some portions of the UMTS core network while still guaranteeing the period 2004-2007 [4]. Moreover, Green House Gases (GHG) emissions have a negative impact on the world

Mellia, Marco

103

The ARIES-RS power core -- Recent development in Li/V designs  

SciTech Connect

The ARIES-RS fusion power plant design study is based on reversed-shear (RS) physics with a Li/V (lithium breeder and vanadium structure) blanket. The reversed-shear discharge has been documented in many large tokamak experiments. The plasma in the RS mode has a high beta, low current, and low current drive requirements. Therefore, it is an attractive physics regime for a fusion power plant. The blanket system based on a Li/V has high temperature operating capability, good tritium breeding, excellent high heat flux removal capability, long structural life time, low activation, low after heat and good safety characteristics. For these reasons, the ARIES-RS reactor study selected Li/V as the reference blanket. The combination of attractive physics and attractive blanket engineering is expected to result in a superior power plant design. This paper summarizes the power core design of the ARIES-RS power plant study.

Sze, D.K.; Billone, M.C.; Hua, T.Q. [and others

1997-04-01

104

Core compressor exit stage study. Volume 1: Blading design. [turbofan engines  

NASA Technical Reports Server (NTRS)

A baseline compressor test stage was designed as well as a candidate rotor and two candidate stators that have the potential of reducing endwall losses relative to the baseline stage. These test stages are typical of those required in the rear stages of advanced, highly-loaded core compressors. The baseline Stage A is a low-speed model of Stage 7 of the 10 stage AMAC compressor. Candidate Rotor B uses a type of meanline in the tip region that unloads the leading edge and loads the trailing edge relative to the baseline Rotor A design. Candidate Stator B embodies twist gradients in the endwall region. Candidate Stator C embodies airfoil sections near the endwalls that have reduced trailing edge loading relative to Stator A. Tests will be conducted using four identical stages of blading so that the designs described will operate in a true multistage environment.

Wisler, D. C.

1977-01-01

105

Analysis of Advanced Fuel Assemblies and Core Designs for the Current and Next Generations of LWRs  

SciTech Connect

The objective of the project is to design and analyze advanced fuel assemblies for use in current and future light water reactors and to assess their ability to reduce the inventory of transuranic elements, while preserving operational safety. The reprocessing of spent nuclear fuel can delay or avoid the need for a second geological repository in the US. Current light water reactor fuel assembly designs under investigation could reduce the plutonium inventory of reprocessed fuel. Nevertheless, these designs are not effective in stabilizing or reducing the inventory of minor actinides. In the course of this project, we developed and analyzed advanced fuel assembly designs with improved thermal transmutation capability regarding transuranic elements and especially minor actinides. These designs will be intended for use in thermal spectrum (e.g., current and future fleet of light water reactors in the US). We investigated various fuel types, namely high burn-up advanced mixed oxides and inert matrix fuels, in various geometrical designs that are compliant with the core internals of current and future light water reactors. Neutronic/thermal hydraulic effects were included. Transmutation efficiency and safety parameters were used to rank and down-select the various designs.

Ragusa, Jean; Vierow, Karen

2011-09-01

106

Preliminary core design studies for the advanced burner reactor over a wide range of conversion ratios.  

SciTech Connect

A consistent set of designs for 1000 MWt commercial-scale sodium-cooled Advance Burner Reactors (ABR) have been developed for both metal and oxide-fueled cores with conversion ratios from breakeven (CR=1.0) to fertile-free (CR=0.0). These designs are expected to satisfy thermal and irradiation damage limits based on the currently available data. The very low conversion ratio designs require fuel that is beyond the current fuel database, which is anticipated to be qualified by and for the Advanced Burned Test Reactor. Safety and kinetic parameters were calculated, but a safety analysis was not performed. Development of these designs was required to achieve the primary goal of this study, which was to generate representative fuel cycle mass flows for system studies of ABRs as part of the Global Nuclear Energy Partnership (GNEP). There are slight variations with conversion ratio but the basic ABR configuration consists of 144 fuel assemblies and between 9 and 22 primary control assemblies for both the metal and oxide-fueled cores. Preliminary design studies indicated that it is feasible to design the ABR to accommodate a wide range of conversion ratio by employing different assembly designs and including sufficient control assemblies to accommodate the large reactivity swing at low conversion ratios. The assemblies are designed to fit within the same geometry, but the size and number of fuel pins within each assembly are significantly different in order to achieve the target conversion ratio while still satisfying thermal limits. Current irradiation experience would allow for a conversion ratio of somewhat below 0.75. The fuel qualification for the first ABR should expand this experience to allow for much lower conversion ratios and higher bunrups. The current designs were based on assumptions about the performance of high and very high enrichment fuel, which results in significant uncertainty about the details of the designs. However, the basic fuel cycle performance trends such as conversion ratio and mass flow parameters are less sensitive to these parameters and the current results should provide a good basis for static and dynamic system analysis. The conversion ratio is fundamentally a ratio of the macroscopic cross section of U-238 capture to that of TRU fission. Since the microscopic cross sections only change moderately with fuel design and isotopic concentration for the fast reactor, a specific conversion ratio requires a specific enrichment. The approximate average charge enrichment (TRU/HM) is 14%, 21%, 33%, 56%, and 100% for conversion ratios of 1.0, 0.75, 0.50, 0.25, and 0.0 for the metal-fueled cores. The approximate average charge enrichment is 17%, 25%, 38%, 60%, and 100% for conversion ratios of 1.0, 0.75, 0.50, 0.25, and 0.0 for the oxide-fueled core. For the split batch cores, the maximum enrichment will be somewhat higher. For both the metal and oxide-fueled cores, the reactivity feedback coefficients and kinetics parameters seem reasonable. The maximum single control assembly reactivity faults may be too large for the low conversion ratio designs. The average reactivity of the primary control assemblies was increased, which may cause the maximum reactivity of the central control assembly to be excessive. The values of the reactivity coefficients and kinetics parameters show that some values appear to improve significantly at lower conversion ratios while others appear far less favorable. Detailed safety analysis is required to determine if these designs have adequate safety margins or if appropriate design modifications are required. Detailed system analysis data has been generated for both metal and oxide-fueled core designs over the entire range of potential burner reactors. Additional data has been calculated for a few alternative fuel cycles. The systems data has been summarized in this report and the detailed data will be provided to the systems analysis team so that static and dynamic system analyses can be performed.

Hoffman, E. A.; Yang, W. S.; Hill, R. N.; Nuclear Engineering Division

2008-05-05

107

Efficient Design and Analysis of Lightweight Reinforced Core Sandwich and PRSEUS Structures  

NASA Technical Reports Server (NTRS)

Design, analysis, and sizing methods for two novel structural panel concepts have been developed and incorporated into the HyperSizer Structural Sizing Software. Reinforced Core Sandwich (RCS) panels consist of a foam core with reinforcing composite webs connecting composite facesheets. Boeing s Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) panels use a pultruded unidirectional composite rod to provide axial stiffness along with integrated transverse frames and stitching. Both of these structural concepts are ovencured and have shown great promise applications in lightweight structures, but have suffered from the lack of efficient sizing capabilities similar to those that exist for honeycomb sandwich, foam sandwich, hat stiffened, and other, more traditional concepts. Now, with accurate design methods for RCS and PRSEUS panels available in HyperSizer, these concepts can be traded and used in designs as is done with the more traditional structural concepts. The methods developed to enable sizing of RCS and PRSEUS are outlined, as are results showing the validity and utility of the methods. Applications include several large NASA heavy lift launch vehicle structures.

Bednarcyk, Brett A.; Yarrington, Phillip W.; Lucking, Ryan C.; Collier, Craig S.; Ainsworth, James J.; Toubia, Elias A.

2012-01-01

108

Design of a Resistively Heated Thermal Hydraulic Simulator for Nuclear Rocket Reactor Cores  

NASA Technical Reports Server (NTRS)

A preliminary design study is presented for a non-nuclear test facility which uses ohmic heating to replicate the thermal hydraulic characteristics of solid core nuclear reactor fuel element passages. The basis for this testing capability is a recently commissioned nuclear thermal rocket environments simulator, which uses a high-power, multi-gas, wall-stabilized constricted arc-heater to produce high-temperature pressurized hydrogen flows representative of reactor core environments, excepting radiation effects. Initially, the baseline test fixture for this non-nuclear environments simulator was configured for long duration hot hydrogen exposure of small cylindrical material specimens as a low cost means of evaluating material compatibility. It became evident, however, that additional functionality enhancements were needed to permit a critical examination of thermal hydraulic effects in fuel element passages. Thus, a design configuration was conceived whereby a short tubular material specimen, representing a fuel element passage segment, is surrounded by a backside resistive tungsten heater element and mounted within a self-contained module that inserts directly into the baseline test fixture assembly. With this configuration, it becomes possible to create an inward directed radial thermal gradient within the tubular material specimen such that the wall-to-gas heat flux characteristics of a typical fuel element passage are effectively simulated. The results of a preliminary engineering study for this innovative concept are fully summarized, including high-fidelity multi-physics thermal hydraulic simulations and detailed design features.

Litchford, Ron J.; Foote, John P.; Ramachandran, Narayanan; Wang, Ten-See; Anghaie, Samim

2007-01-01

109

An intrinsically safe facility for forefront research and training on nuclear technologies — Core design  

NASA Astrophysics Data System (ADS)

The core of a subcritical, low-power research reactor in a lead matrix has been designed using the MCNPX code. The main parameters, like geometry, material composition in the fuel assembly and reflector size, have been optimized for a k eff ˜ 0.95 and a thermal power around 200 Kw. A 70 Mev, 1 mA proton beam incident on a beryllium target has been assumed as neutron source and the corresponding thermal power distribution and neutron fluxes in the reactor have been simulated.

Viberti, C. M.; Ricco, G.

2014-04-01

110

A single aromatic core mutation converts a designed "primitive" protein from halophile to mesophile folding.  

PubMed

The halophile environment has a number of compelling aspects with regard to the origin of structured polypeptides (i.e., proteogenesis) and, instead of a curious niche that living systems adapted into, the halophile environment is emerging as a candidate "cradle" for proteogenesis. In this viewpoint, a subsequent halophile-to-mesophile transition was a key step in early evolution. Several lines of evidence indicate that aromatic amino acids were a late addition to the codon table and not part of the original "prebiotic" set comprising the earliest polypeptides. We test the hypothesis that the availability of aromatic amino acids could facilitate a halophile-to-mesophile transition by hydrophobic core-packing enhancement. The effects of aromatic amino acid substitutions were evaluated in the core of a "primitive" designed protein enriched for the 10 prebiotic amino acids (A,D,E,G,I,L,P,S,T,V)-having an exclusively prebiotic core and requiring halophilic conditions for folding. The results indicate that a single aromatic amino acid substitution is capable of eliminating the requirement of halophile conditions for folding of a "primitive" polypeptide. Thus, the availability of aromatic amino acids could have facilitated a critical halophile-to-mesophile protein folding adaptation-identifying a selective advantage for the incorporation of aromatic amino acids into the codon table. PMID:25297559

Longo, Liam M; Tenorio, Connie A; Kumru, Ozan S; Middaugh, C Russell; Blaber, Michael

2015-01-01

111

Calculation of Design Parameters for an Equilibrium LEU Core in the NBSR  

SciTech Connect

A plan is being developed for the conversion of the NIST research reactor (NBSR) from high-enriched uranium (HEU) fuel to low-enriched uranium (LEU) fuel. Previously, the design of the LEU fuel had been determined in order to provide the users of the NBSR with the same cycle length as exists for the current HEU fueled reactor. The fuel composition at different points within an equilibrium fuel cycle had also been determined. In the present study, neutronics parameters have been calculated for these times in the fuel cycle for both the existing HEU and the proposed LEU equilibrium cores. The results showed differences between the HEU and LEU cores that would not lead to any significant changes in the safety analysis for the converted core. In general the changes were reasonable except that the figure-of-merit for neutrons that can be used by experimentalists shows there will be a 10% reduction in performance. The calculations included kinetics parameters, reactivity coefficients, reactivity worths of control elements and abnormal configurations, and power distributions.

Hanson, A.L.; Diamond, D.

2011-09-30

112

Common Core State Standards for Mathematics. Appendix A: Designing High School Mathematics Courses Based on the Common Core State Standards  

ERIC Educational Resources Information Center

The Common Core State Standards (CCSS) for Mathematics are organized by grade level in Grades K-8. At the high school level, the standards are organized by conceptual category (number and quantity, algebra, functions, geometry, modeling and probability and statistics), showing the body of knowledge students should learn in each category to be…

Common Core State Standards Initiative, 2011

2011-01-01

113

77 FR 36611 - Core Principles and Other Requirements for Designated Contract Markets  

Federal Register 2010, 2011, 2012, 2013, 2014

...rule enforcement program because prompt resolution of investigations is essential to discouraging...15) Core Principle 14: Dispute Resolution The new guidance for Core Principle...benefits of administering a dispute resolution program under former Core...

2012-06-19

114

Small Launch Vehicle Design Approaches: Clustered Cores Compared with Multi-Stage Inline Concepts  

NASA Technical Reports Server (NTRS)

In an effort to better define small launch vehicle design options two approaches were investigated from the small launch vehicle trade space. The primary focus was to evaluate a clustered common core design against a purpose built inline vehicle. Both designs focused on liquid oxygen (LOX) and rocket propellant grade kerosene (RP-1) stages with the terminal stage later evaluated as a LOX/methane (CH4) stage. A series of performance optimization runs were done in order to minimize gross liftoff weight (GLOW) including alternative thrust levels, delivery altitude for payload, vehicle length to diameter ratio, alternative engine feed systems, re-evaluation of mass growth allowances, passive versus active guidance systems, and rail and tower launch methods. Additionally manufacturability, cost, and operations also play a large role in the benefits and detriments for each design. Presented here is the Advanced Concepts Office's Earth to Orbit Launch Team methodology and high level discussion of the performance trades and trends of both small launch vehicle solutions along with design philosophies that shaped both concepts. Without putting forth a decree stating one approach is better than the other; this discussion is meant to educate the community at large and let the reader determine which architecture is truly the most economical; since each path has such a unique set of limitations and potential payoffs.

Waters, Eric D.; Beers, Benjamin; Esther, Elizabeth; Philips, Alan; Threet, Grady E., Jr.

2013-01-01

115

Development of Optimized Core Design and Analysis Methods for High Power Density BWRs  

NASA Astrophysics Data System (ADS)

Increasing the economic competitiveness of nuclear energy is vital to its future. Improving the economics of BWRs is the main goal of this work, focusing on designing cores with higher power density, to reduce the BWR capital cost. Generally, the core power density in BWRs is limited by the thermal Critical Power of its assemblies, below which heat removal can be accomplished with low fuel and cladding temperatures. The present study investigates both increases in the heat transfer area between ~he fuel and coolant and changes in operating parameters to achieve higher power levels while meeting the appropriate thermal as well as materials and neutronic constraints. A scoping study is conducted under the constraints of using fuel with cylindrical geometry, traditional materials and enrichments below 5% to enhance its licensability. The reactor vessel diameter is limited to the largest proposed thus far. The BWR with High power Density (BWR-HD) is found to have a power level of 5000 MWth, equivalent to 26% uprated ABWR, resulting into 20% cheaper O&M and Capital costs. This is achieved by utilizing the same number of assemblies, but with wider 16x16 assemblies and 50% shorter active fuel than that of the ABWR. The fuel rod diameter and pitch are reduced to just over 45% of the ABWR values. Traditional cruciform form control rods are used, which restricts the assembly span to less than 1.2 times the current GE14 design due to limitation on shutdown margin. Thus, it is possible to increase the power density and specific power by 65%, while maintaining the nominal ABWR Minimum Critical Power Ratio (MCPR) margin. The plant systems outside the vessel are assumed to be the same as the ABWR-Il design, utilizing a combination of active and passive safety systems. Safety analyses applied a void reactivity coefficient calculated by SIMULA TE-3 for an equilibrium cycle core that showed a 15% less negative coefficient for the BWR-HD compared to the ABWR. The feedwater temperature was kept the same for the BWR-HD and ABWR which resulted in 4 °K cooler core inlet temperature for the BWR-HD given that its feedwater makes up a larger fraction of total core flow. The stability analysis using the STAB and S3K codes showed satisfactory results for the hot channel, coupled regional out-of-phase and coupled core-wide in-phase modes. A RELAPS model of the ABWR system was constructed and applied to six transients for the BWR-HD and ABWR. The 6MCPRs during all the transients were found to be equal or less for the new design and the core remained covered for both. The lower void coefficient along with smaller core volume proved to be advantages for the simulated transients. Helical Cruciform Fuel (HCF) rods were proposed in prior MIT studies to enhance the fuel surface to volume ratio. In this work, higher fidelity models (e.g. CFD instead of subchannel methods for the hydraulic behaviour) are used to investigate the resolution needed for accurate assessment of the HCF design. For neutronics, conserving the fuel area of cylindrical rods results in a different reactivity level with a lower void coefficient for the HCF design. In single-phase flow, for which experimental results existed, the friction factor is found to be sensitive to HCF geometry and cannot be calculated using current empirical models. A new approach for analysis of flow crisis conditions for HCF rods in the context of Departure from Nucleate Boiling (DNB) and dryout using the two phase interface tracking method was proposed and initial results are presented. It is shown that the twist of the HCF rods promotes detachment of a vapour bubble along the elbows which indicates no possibility for an early DNB for the HCF rods and in fact a potential for a higher DNB heat flux. Under annular flow conditions, it was found that the twist suppressed the liquid film thickness on the HCF rods, at the locations of the highest heat flux, which increases the possibility of reaching early dryout. It was also shown that modeling the 3D heat and stress distribution in the HCF rods is necessary

Shirvan, Koroush

116

Optimal design at inner core of the shaped pyramidal truss structure  

SciTech Connect

Sandwich material is a type of composite material with lightweight, high strength, good dynamic properties and high bending stiffness-to-weight ratio. This can be found well such structures in the nature (for example, internal structure of bones, plants, etc.). New trend which prefers eco-friendly products and energy efficiency is emerging in industries recently. Demand for materials with high strength and light weight is also increasing. In line with these trends, researches about manufacturing methods of sandwich material have been actively conducted. In this study, a sandwich structure named as “Shaped Pyramidal Truss Structure” is proposed to improve mechanical strength and to apply a manufacturing process suitable for massive production. The new sandwich structure was designed to enhance compressive strength by changing the cross-sectional shape at the central portion of the core. As the next step, optimization of the shape was required. Optimization technique used here was the SZGA(Successive Zooming Genetic Algorithm), which is one of GA(Genetic Algorithm) methods gradually reducing the area of design variable. The objective function was defined as moment of inertia of the cross-sectional shape of the strut. The control points of cubic Bezier curve, which was assumed to be the shape of the cross section, were used as design variables. By using FEM simulation, it was found that the structure exhibited superior mechanical properties compared to the simple design of the prior art.

Lee, Sung-Uk; Yang, Dong-Yol [Department of Mechanical Engineering, KAIST 291 Daehak-ro (373-1 Guseong-dong), Yuseong-gu, Dae-jeon, 305-701 (Korea, Republic of)

2013-12-16

117

Optimal design at inner core of the shaped pyramidal truss structure  

NASA Astrophysics Data System (ADS)

Sandwich material is a type of composite material with lightweight, high strength, good dynamic properties and high bending stiffness-to-weight ratio. This can be found well such structures in the nature (for example, internal structure of bones, plants, etc.). New trend which prefers eco-friendly products and energy efficiency is emerging in industries recently. Demand for materials with high strength and light weight is also increasing. In line with these trends, researches about manufacturing methods of sandwich material have been actively conducted. In this study, a sandwich structure named as "Shaped Pyramidal Truss Structure" is proposed to improve mechanical strength and to apply a manufacturing process suitable for massive production. The new sandwich structure was designed to enhance compressive strength by changing the cross-sectional shape at the central portion of the core. As the next step, optimization of the shape was required. Optimization technique used here was the SZGA(Successive Zooming Genetic Algorithm), which is one of GA(Genetic Algorithm) methods gradually reducing the area of design variable. The objective function was defined as moment of inertia of the cross-sectional shape of the strut. The control points of cubic Bezier curve, which was assumed to be the shape of the cross section, were used as design variables. By using FEM simulation, it was found that the structure exhibited superior mechanical properties compared to the simple design of the prior art.

Lee, Sung-Uk; Yang, Dong-Yol

2013-12-01

118

Design Review Report for formal review of safety class features of exhauster system for rotary mode core sampling  

SciTech Connect

Report documenting Formal Design Review conducted on portable exhausters used to support rotary mode core sampling of Hanford underground radioactive waste tanks with focus on Safety Class design features and control requirements for flammable gas environment operation and air discharge permitting compliance.

JANICEK, G.P.

2000-06-08

119

America's Next Great Ship: Space Launch System Core Stage Transitioning from Design to Manufacturing  

NASA Technical Reports Server (NTRS)

The Space Launch System (SLS) Program is essential to achieving the Nation's and NASA's goal of human exploration and scientific investigation of the solar system. As a multi-element program with emphasis on safety, affordability, and sustainability, SLS is becoming America's next great ship of exploration. The SLS Core Stage includes avionics, main propulsion system, pressure vessels, thrust vector control, and structures. Boeing manufactures and assembles the SLS core stage at the Michoud Assembly Facility (MAF) in New Orleans, LA, a historical production center for Saturn V and Space Shuttle programs. As the transition from design to manufacturing progresses, the importance of a well-executed manufacturing, assembly, and operation (MA&O) plan is crucial to meeting performance objectives. Boeing employs classic techniques such as critical path analysis and facility requirements definition as well as innovative approaches such as Constraint Based Scheduling (CBS) and Cirtical Chain Project Management (CCPM) theory to provide a comprehensive suite of project management tools to manage the health of the baseline plan on both a macro (overall project) and micro level (factory areas). These tools coordinate data from multiple business systems and provide a robust network to support Material & Capacity Requirements Planning (MRP/CRP) and priorities. Coupled with these tools and a highly skilled workforce, Boeing is orchestrating the parallel buildup of five major sub assemblies throughout the factory. Boeing and NASA are transforming MAF to host state of the art processes, equipment and tooling, the most prominent of which is the Vertical Assembly Center (VAC), the largest weld tool in the world. In concert, a global supply chain is delivering a range of structural elements and component parts necessary to enable an on-time delivery of the integrated Core Stage. SLS is on plan to launch humanity into the next phase of space exploration.

Birkenstock, Benjamin; Kauer, Roy

2014-01-01

120

Melt spreading code assessment, modifications, and application to the EPR core catcher design.  

SciTech Connect

The Evolutionary Power Reactor (EPR) is under consideration by various utilities in the United States to provide base load electrical production, and as a result the design is undergoing a certification review by the U.S. Nuclear Regulatory Commission (NRC). The severe accident design philosophy for this reactor is based upon the fact that the projected power rating results in a narrow margin for in-vessel melt retention by external cooling of the reactor vessel. As a result, the design addresses ex-vessel core melt stabilization using a mitigation strategy that includes: (1) an external core melt retention system to temporarily hold core melt released from the vessel; (2) a layer of 'sacrificial' material that is admixed with the melt while in the core melt retention system; (3) a melt plug in the lower part of the retention system that, when failed, provides a pathway for the mixture to spread to a large core spreading chamber; and finally, (4) cooling and stabilization of the spread melt by controlled top and bottom flooding. The overall concept is illustrated in Figure 1.1. The melt spreading process relies heavily on inertial flow of a low-viscosity admixed melt to a segmented spreading chamber, and assumes that the melt mass will be distributed to a uniform height in the chamber. The spreading phenomenon thus needs to be modeled properly in order to adequately assess the EPR design. The MELTSPREAD code, developed at Argonne National Laboratory, can model segmented, and both uniform and nonuniform spreading. The NRC is thus utilizing MELTSPREAD to evaluate melt spreading in the EPR design. MELTSPREAD was originally developed to support resolution of the Mark I containment shell vulnerability issue. Following closure of this issue, development of MELTSPREAD ceased in the early 1990's, at which time the melt spreading database upon which the code had been validated was rather limited. In particular, the database that was utilized for initial validation consisted of: (1) comparison to an analytical solution for the dam break problem, (2) water spreading tests in a 1/10 linear scale model of the Mark I containment by Theofanous et al., and (3) steel spreading tests by Suzuki et al. that were also conducted in a geometry similar to the Mark I. The objective of this work was to utilize the MELTSPREAD code to check the assumption of uniform melt spreading in the EPR core catcher design. As a starting point for the project, the code was validated against the worldwide melt spreading database that emerged after the code was originally written in the very early 1990's. As part of this exercise, the code was extensively modified and upgraded to incorporate findings from these various analytical and experiment programs. In terms of expanding the ability of the code to analyze various melt simulant experiments, the options to input user-specified melt and/or substrate material properties was added. The ability to perform invisicid and/or adiabatic spreading analysis was also added so that comparisons with analytical solutions and isothermal spreading tests could be carried out. In terms of refining the capability to carry out reactor material melt spreading analyses, the code was upgraded with a new melt viscosity model; the capability was added to treat situations in which solid fraction buildup between the liquidus-solidus is non-linear; and finally, the ability to treat an interfacial heat transfer resistance between the melt and substrate was incorporated. This last set of changes substantially improved the predictive capability of the code in terms of addressing reactor material melt spreading tests. Aside from improvements and upgrades, a method was developed to fit the model to the various melt spreading tests in a manner that allowed uncertainties in the model predictions to be statistically characterized. With these results, a sensitivity study was performed to investigate the assumption of uniform spreading in the EPR core catcher that addressed parametric variations in: (1) melt pour mass, (2) melt composition, (3) me

Farmer, M. T .; Nuclear Engineering Division

2009-03-30

121

Chemical and Colloidal Stability of Carboxylated Core-Shell Magnetite Nanoparticles Designed for Biomedical Applications  

PubMed Central

Despite the large efforts to prepare super paramagnetic iron oxide nanoparticles (MNPs) for biomedical applications, the number of FDA or EMA approved formulations is few. It is not known commonly that the approved formulations in many instances have already been withdrawn or discontinued by the producers; at present, hardly any approved formulations are produced and marketed. Literature survey reveals that there is a lack for a commonly accepted physicochemical practice in designing and qualifying formulations before they enter in vitro and in vivo biological testing. Such a standard procedure would exclude inadequate formulations from clinical trials thus improving their outcome. Here we present a straightforward route to assess eligibility of carboxylated MNPs for biomedical tests applied for a series of our core-shell products, i.e., citric acid, gallic acid, poly(acrylic acid) and poly(acrylic acid-co-maleic acid) coated MNPs. The discussion is based on physicochemical studies (carboxylate adsorption/desorption, FTIR-ATR, iron dissolution, zeta potential, particle size, coagulation kinetics and magnetization measurements) and involves in vitro and in vivo tests. Our procedure can serve as an example to construct adequate physico-chemical selection strategies for preparation of other types of core-shell nanoparticles as well. PMID:23857054

Szekeres, Márta; Tóth, Ildikó Y.; Illés, Erzsébet; Hajdú, Angéla; Zupkó, István; Farkas, Katalin; Oszlánczi, Gábor; Tiszlavicz, László; Tombácz, Etelka

2013-01-01

122

Novel design of dual-core microstructured fiber with enhanced longitudinal strain sensitivity  

NASA Astrophysics Data System (ADS)

Constantly refined technology of manufacturing increasingly complex photonic crystal fibers (PCF) leads to new optical fiber sensor concepts. The ways of enhancing the influence of external factors (such as hydrostatic pressure, temperature, acceleration) on the fiber propagating conditions are commonly investigated in literature. On the other hand longitudinal strain analysis, due to the calculation difficulties caused by the three dimensional computation, are somehow neglected. In this paper we show results of such a 3D numerical simulation and report methods of tuning the fiber strain sensitivity by changing the fiber microstructure and core doping level. Furthermore our approach allows to control whether the modes' effective refractive index is increasing or decreasing with strain, with the possibility of achieving zero strain sensitivity with specific fiber geometries. The presented numerical analysis is compared with experimental results of the fabricated fibers characterization. Basing on the aforementioned methodology we propose a novel dual-core fiber design with significantly increased sensitivity to longitudinal strain for optical fiber sensor applications. Furthermore the reported fiber satisfies all conditions necessary for commercial applications like good mode matching with standard single-mode fiber, low confinement loss and ease of manufacturing with the stack-and-draw technique. Such fiber may serve as an integrated Mach-Zehnder interferometer when highly coherent source is used. With the optimization of single mode transmission to 850 nm, we propose a VCSEL source to be used in order to achieve a low-cost, reliable and compact strain sensing transducer.

Szostkiewicz, Lukasz; Tenderenda, T.; Napierala, M.; Szyma?ski, M.; Murawski, M.; Mergo, P.; Lesiak, P.; Marc, P.; Jaroszewicz, L. R.; Nasilowski, T.

2014-05-01

123

Parameter Design and Optimal Control of an Open Core Flywheel Energy Storage System  

NASA Technical Reports Server (NTRS)

In low earth orbit (LEO) satellite applications spacecraft power is provided by photovoltaic cells and batteries. To overcome battery shortcomings the University of Maryland, working in cooperation with NASA/GSFC and NASA/LeRC, has developed a magnetically suspended flywheel for energy storage applications. The system is referred to as an Open Core Composite Flywheel (OCCF) energy storage system. Successful application of flywheel energy storage requires integration of several technologies, viz. bearings, rotor design, motor/generator, power conditioning, and system control. In this paper we present a parameter design method which has been developed for analyzing the linear SISO model of the magnetic bearing controller for the OCCF. The objective of this continued research is to principally analyze the magnetic bearing system for nonlinear effects in order to increase the region of stability, as determined by high speed and large air gap control. This is achieved by four tasks: (1) physical modeling, design, prototyping, and testing of an improved magnetically suspended flywheel energy storage system, (2) identification of problems that limit performance and their corresponding solutions, (3) development of a design methodology for magnetic bearings, and (4) design of an optimal controller for future high speed applications. Both nonlinear SISO and MIMO models of the magnetic system were built to study limit cycle oscillations and power amplifier saturation phenomenon observed in experiments. The nonlinear models include the inductance of EM coils, the power amplifier saturation, and the physical limitation of the flywheel movement as discussed earlier. The control program EASY5 is used to study the nonlinear SISO and MIMO models. Our results have shown that the characteristics and frequency responses of the magnetic bearing system obtained from modeling are comparable to those obtained experimentally. Although magnetic saturation is shown in the bearings, there are good correlations between the theoretical model and experimental data. Both simulation and experiment confirm large variations of the magnetic bearing characteristics due to air gap growth. Therefore, the gap growth effect should be considered in the magnetic bearing system design. Additionally, the magnetic bearing control system will be compared to other design methods using not only parameter design but H-infinity optimal control and mu synthesis.

Pang, D.; Anand, D. K.; Kirk, J. A.

1996-01-01

124

The design of dual emitting cores for green thermally activated delayed fluorescent materials.  

PubMed

Dual emitting cores for thermally activated delayed fluorescent (TADF) emitters were developed. Relative to the corresponding TADF emitter with a single emitting core the TADF emitter with a dual emitting core, 3,3',5,5'-tetra(carbazol-9-yl)-[1,1'-biphenyl]-2,2',6,6'-tetracarbonitrile, showed enhanced light absorption accompanied by a high photoluminescence quantum yield. The quantum and power efficiencies of the TADF devices were enhanced by the dual emitting cores. PMID:25727757

Cho, Yong Joo; Jeon, Sang Kyu; Chin, Byung Doo; Yu, Eunsun; Lee, Jun Yeob

2015-04-20

125

MIC-SVM: Designing A Highly Efficient Support Vector Machine For Advanced Modern Multi-Core and Many-Core Architectures  

SciTech Connect

Support Vector Machine (SVM) has been widely used in data-mining and Big Data applications as modern commercial databases start to attach an increasing importance to the analytic capabilities. In recent years, SVM was adapted to the ?eld of High Performance Computing for power/performance prediction, auto-tuning, and runtime scheduling. However, even at the risk of losing prediction accuracy due to insuf?cient runtime information, researchers can only afford to apply of?ine model training to avoid signi?cant runtime training overhead. To address the challenges above, we designed and implemented MICSVM, a highly efficient parallel SVM for x86 based multi-core and many core architectures, such as the Intel Ivy Bridge CPUs and Intel Xeon Phi coprocessor (MIC).

You, Yang; Song, Shuaiwen; Fu, Haohuan; Marquez, Andres; Mehri Dehanavi, Maryam; Barker, Kevin J.; Cameron, Kirk; Randles, Amanda; Yang, Guangwen

2014-08-16

126

Mixed enrichment core design for the NC State University PULSTAR Reactor  

SciTech Connect

The North Carolina State University PULSTAR Reactor license was renewed for an additional 20 years of operation on April 30, 1997. The relicensing period added additional years to the facility operating time through the end of the second license period, increasing the excess reactivity needs as projected in 1988. In 1995, the Nuclear Reactor Program developed a strategic plan that addressed the future maintenance, development, and utilization of the facility. Goals resulting from this plan included increased academic utilization of the facility in accordance with its role as a university research facility, and increased industrial service use in accordance with the mission of a land grant university. The strategic plan was accepted, and it is the intent of the College of Engineering to operate the PULSTAR Reactor as a going concern through at least the end of the current license period. In order to reach the next relicensing review without prejudice due to low excess reactivity, it is desired to maintain sufficient excess reactivity so that, if relicensed again, the facility could continue to operate without affecting users until new fuel assistance was provided. During the NC State University license renewal, the operation of the PULSTAR Reactor at the State University of New York at Buffalo (SUNY Buffalo) was terminated. At that time, the SUNY Buffalo facility had about 240 unused PULSTAR Reactor fuel pins with 6% enrichment. The objective of the work reported here was to develop a mixed enrichment core design for the NC State University PULSTAR reactor which would: (1) demonstrate that 6% enriched SUNY buffalo fuel could be used in the NC State University PULSTAR Reactor within the existing technical specification safety limits for core physics parameters; (2) show that use of this fuel could permit operating the NC State University PULSTAR Reactor to 2017 with increased utilization; and (3) assure that the decision whether or not to relicense the facility would not be prejudiced by reduced operations due to low excess reactivity.

Mayo, C.W.; Verghese, K.; Huo, Y.G.

1997-12-01

127

The design and implementation of the parallel out-of-core ScaLAPACK LU, QR and Cholesky factorization routines  

SciTech Connect

This paper describes the design and implementation of three core factorization routines--LU, QR and Cholesky--included in the out-of-core extension of ScaLAPACK. These routines allow the factorization and solution of a dense system that is too large to fit entirely in physical memory. An image of the full matrix is maintained on disk and the factorization routines transfer sub-matrices into memory. The left-looking column-oriented variant of the factorization algorithm is implemented to reduce the disk I/O traffic. The routines are implemented using a portable I/O interface and utilize high performance ScaLAPACK factorization routines as in-core computational kernels. The authors present the details of the implementation for the out-of-core ScaLAPACK factorization routines, as well as performance and scalability results on the Intel Paragon.

D`Azevedo, E.F.; Dongarra, J.J.

1997-04-01

128

High accuracy modeling for advanced nuclear reactor core designs using Monte Carlo based coupled calculations  

NASA Astrophysics Data System (ADS)

The main objective of this PhD research is to develop a high accuracy modeling tool using a Monte Carlo based coupled system. The presented research comprises the development of models to include the thermal-hydraulic feedback to the Monte Carlo method and speed-up mechanisms to accelerate the Monte Carlo criticality calculation. Presently, deterministic codes based on the diffusion approximation of the Boltzmann transport equation, coupled with channel-based (or sub-channel based) thermal-hydraulic codes, carry out the three-dimensional (3-D) reactor core calculations of the Light Water Reactors (LWRs). These deterministic codes utilize nuclear homogenized data (normally over large spatial zones, consisting of fuel assembly or parts of fuel assembly, and in the best case, over small spatial zones, consisting of pin cell), which is functionalized in terms of thermal-hydraulic feedback parameters (in the form of off-line pre-generated cross-section libraries). High accuracy modeling is required for advanced nuclear reactor core designs that present increased geometry complexity and material heterogeneity. Such high-fidelity methods take advantage of the recent progress in computation technology and coupled neutron transport solutions with thermal-hydraulic feedback models on pin or even on sub-pin level (in terms of spatial scale). The continuous energy Monte Carlo method is well suited for solving such core environments with the detailed representation of the complicated 3-D problem. The major advantages of the Monte Carlo method over the deterministic methods are the continuous energy treatment and the exact 3-D geometry modeling. However, the Monte Carlo method involves vast computational time. The interest in Monte Carlo methods has increased thanks to the improvements of the capabilities of high performance computers. Coupled Monte-Carlo calculations can serve as reference solutions for verifying high-fidelity coupled deterministic neutron transport methods with detailed and accurate thermal-hydraulic models. The development of such reference high-fidelity coupled multi-physics scheme is described in this dissertation on the basis of MCNP5, NEM, NJOY and COBRA-TF (CTF) computer codes. This work presents results from studies performed and implemented at the Pennsylvania State University (PSU) on both accelerating Monte Carlo criticality calculations by using hybrid nodal diffusion Monte Carlo schemes and thermal-hydraulic feedback modeling in Monte Carlo core calculations. The hybrid MCNP5/CTF/NEM/NJOY coupled code system is proposed and developed in this dissertation work. The hybrid coupled code system contains a special interface developed to update the required MCNP5 input changes to account for dimension and density changes provided by the thermal-hydraulics feedback module. The interface has also been developed to extract the flux and reaction rates calculated by MCNP5 to later transform the data into the power feedback needed by CTF (axial and radial peaking factors). The interface is contained in a master program that controls the flow of the calculations. Both feedback modules (thermal-hydraulic and power subroutines) use a common internal interface to further accelerate the data exchange. One of the most important steps to correctly include the thermal hydraulic feedback into MCNP5 calculations begins with temperature dependent cross section libraries. If the cross sections used for the calculations are not at the correct temperature, the temperature feedback cannot be included into MCNP5 (referred to the effect of temperature on cross sections: Doppler boarding of resolve and unresolved resonances, thermal scattering and elastic scattering). The only method of considering the temperature effects on cross sections is through the generation (or as introduced in this dissertation through a novel interpolation mechanism) of continuous energy temperature-dependent cross section libraries. An automated methodology for generation of continuous energy temperature-dependent cross section libraries has been developed

Espel, Federico Puente

129

The fuzzy clearing approach for a niching genetic algorithm applied to a nuclear reactor core design optimization problem  

Microsoft Academic Search

This article extends previous efforts on genetic algorithms (GAs) applied to a core design optimization problem. We introduce the application of a new Niching Genetic Algorithm (NGA) to this problem and compare its performance to these previous works. The optimization problem consists in adjusting several reactor cell parameters, such as dimensions, enrichment and materials, in order to minimize the average

Wagner F. Sacco; Marcelo D. Machado; Cláudio M. N. A. Pereira; Roberto Schirru

2004-01-01

130

Design of S-Band Erbium-Doped Concentric Dual-Core Photonic Crystal Fiber Amplifiers With ASE Suppression  

Microsoft Academic Search

In this paper, we theoretically design and numerically demonstrate a large mode area and single-mode erbium-doped photonic crystal fiber (PCF) amplifier operating in the S-band with a complete suppression of amplified spontaneous emission (ASE) and very low Raman gain coefficient at 980-nm pump. The proposed fiber design is based on a dual-concentric core refractive index profile and is solved through

Shailendra Kumar Varshney; Kunimasa Saitoh; Masanori Koshiba; Bishnu P. Pal; Ravindra K. Sinha

2009-01-01

131

Journal of NUCLEAR SCIENCE and TECHNOLOGY, Vol. 39, No. 11, p. 11691181 (November 2002) Conceptual Design of a Modular Island Core Fast Breeder Reactor "RAPID-M"  

E-print Network

using the multi-point reactor kinetics equations to accommodate the modular core configura- tion Design of a Modular Island Core Fast Breeder Reactor "RAPID-M" Mitsuru KAMBE Central Research Institute and accepted September 10, 2002) A metal fueled modular island core sodium cooled fast breeder reactor concept

Laughlin, Robert B.

132

Modular Approach to Launch Vehicle Design Based on a Common Core Element  

NASA Technical Reports Server (NTRS)

With a heavy lift launch vehicle as the centerpiece of our nation's next exploration architecture's infrastructure, the Advanced Concepts Office at NASA's Marshall Space Flight Center initiated a study to examine the utilization of elements derived from a heavy lift launch vehicle for other potential launch vehicle applications. The premise of this study is to take a vehicle concept, which has been optimized for Lunar Exploration, and utilize the core stage with other existing or near existing stages and boosters to determine lift capabilities for alternative missions. This approach not only yields a vehicle matrix with a wide array of capabilities, but also produces an evolutionary pathway to a vehicle family based on a minimum development and production cost approach to a launch vehicle system architecture, instead of a purely performance driven approach. The upper stages and solid rocket booster selected for this study were chosen to reflect a cross-section of: modified existing assets in the form of a modified Delta IV upper stage and Castor-type boosters; potential near term launch vehicle component designs including an Ares I upper stage and 5-segment boosters; and longer lead vehicle components such as a Shuttle External Tank diameter upper stage. The results of this approach to a modular launch system are given in this paper.

Creech, Dennis M.; Threet, Grady E., Jr.; Philips, Alan D.; Waters, Eric D.; Baysinger, Mike

2010-01-01

133

Measurements of the impedance matrix of a thermoacoustic core: applications to the design of thermoacoustic engines.  

PubMed

The successful design of a thermoacoustic engine depends on the appropriate description of the processes involved inside the thermoacoustic core (TAC). This is a difficult task when considering the complexity of both the heat transfer phenomena and the geometry of the porous material wherein the thermoacoustic amplification process occurs. An attempt to getting round this difficulty consists in measuring the TAC transfer matrix under various heating conditions, the measured transfer matrices being exploited afterward into analytical models describing the complete apparatus. In this paper, a method based on impedance measurements is put forward, which allows the accurate measurement of the TAC transfer matrix, contrarily to the classical two-load method. Four different materials are tested, each one playing as the porous element allotted inside the TAC, which is submitted to different temperature gradients to promote thermoacoustic amplification. The experimental results are applied to the modeling of basic standing-wave and traveling-wave engines, allowing the prediction of the engine operating frequency and thermoacoustic amplification gain, as well as the optimum choice of the components surrounding the TAC. PMID:23654373

Bannwart, Flávio C; Penelet, Guillaume; Lotton, Pierrick; Dalmont, Jean-Pierre

2013-05-01

134

DYNAMICO, an icosahedral hydrostatic dynamical core designed for consistency and versatility  

NASA Astrophysics Data System (ADS)

The design of the icosahedral dynamical core DYNAMICO is presented. DYNAMICO solves the multi-layer rotating shallow-water equations, a compressible variant of the same equivalent to a discretization of the hydrostatic primitive equations in a Lagrangian vertical coordinate, and the primitive equations in a hybrid mass-based vertical coordinate. The common Hamiltonian structure of these sets of equations is exploited to formulate energy-conserving spatial discretizations in a unified way. The horizontal mesh is a quasi-uniform icosahedral C-grid obtained by subdivision of a regular icosahedron. Control volumes for mass, tracers and entropy/potential temperature are the hexagonal cells of the Voronoi mesh to avoid the fast numerical modes of the triangular C-grid. The horizontal discretization is that of Ringler et al. (2010), whose discrete quasi-Hamiltonian structure is identified. The prognostic variables are arranged vertically on a Lorenz grid with all thermodynamical variables collocated with mass. The vertical discretization is obtained from the three-dimensional Hamiltonian formulation. Tracers are transported using a second-order finite volume scheme with slope limiting for positivity. Explicit Runge-Kutta time integration is used for dynamics and forward-in-time integration with horizontal/vertical splitting is used for tracers. Most of the model code is common to the three sets of equations solved, making it easier to develop and validate each piece of the model separately. Representative three-dimensional test cases are run and analyzed, showing correctness of the model. The design permits to consider several extensions in the near future, from higher-order transport to more general dynamics, especially deep-atmosphere and non-hydrostatic equations.

Dubos, T.; Dubey, S.; Tort, M.; Mittal, R.; Meurdesoif, Y.; Hourdin, F.

2015-02-01

135

Design and Performance Improvements of the Prototype Open Core Flywheel Energy Storage System  

NASA Technical Reports Server (NTRS)

A prototype magnetically suspended composite flywheel energy storage (FES) system is operating at the University of Maryland. This system, designed for spacecraft applications, incorporates recent advances in the technologies of composite materials, magnetic suspension, and permanent magnet brushless motor/generator. The current system is referred to as an Open Core Composite Flywheel (OCCF) energy storage system. This paper will present design improvements for enhanced and robust performance. Initially, when the OCCF prototype was spun above its first critical frequency of 4,500 RPM, the rotor movement would exceed the space available in the magnetic suspension gap and touchdown on the backup mechanical bearings would occur. On some occasions it was observed that, after touchdown, the rotor was unable to re-suspend as the speed decreased. Additionally, it was observed that the rotor would exhibit unstable oscillations when the control system was initially turned on. Our analysis suggested that the following problems existed: (1) The linear operating range of the magnetic bearings was limited due to electrical and magnetic saturation; (2) The inductance of the magnetic bearings was affecting the transient response of the system; (3) The flywheel was confined to a small movement because mechanical components could not be held to a tight tolerance; and (4) The location of the touchdown bearing magnifies the motion at the pole faces of the magnetic bearings when the linear range is crucial. In order to correct these problems an improved design of the flywheel energy storage system was undertaken. The magnetic bearings were re-designed to achieve a large linear operating range and to withstand load disturbances of at least 1 g. The external position transducers were replaced by a unique design which were resistant to magnetic field noise and allowed cancellation of the radial growth of the flywheel at high speeds. A central rod was utilized to ensure the concentricity of the magnetic bearings, the motor/generator, and the mechanical touchdown bearings. In addition, the mechanical touchdown bearings were placed at two ends of the magnetic bearing stack to restrict the motion at pole faces. A composite flywheel was made using a multi-ring interference assembled design for a high specific energy density. To achieve a higher speed and better efficiency, a permanent magnet DC brushless motor was specially designed and fabricated. A vacuum enclosure was constructed to eliminate windage losses for testing at high speeds. With the new improvements the OCCF system was tested to 20,000 RPM with a total stored energy of 15.9 WH and an angular momentum of 54.8 N-m-s (40.4 lb-ft-s). Motor current limitation, caused by power loss in the magnetic bearings, was identified as causing the limit in upper operating speed.

Pang, D.; Anand, D. K. (Editor); Kirk, J. A. (Editor)

1996-01-01

136

Tuning light absorption in core/shell silicon nanowire photovoltaic devices through morphological design.  

PubMed

Subwavelength diameter semiconductor nanowires can support optical resonances with anomalously large absorption cross sections, and thus tailoring these resonances to specific frequencies could enable a number of nanophotonic applications. Here, we report the design and synthesis of core/shell p-type/intrinsic/n-type (p/i/n) Si nanowires (NWs) with different sizes and cross-sectional morphologies as well as measurement and simulation of photocurrent spectra from single-NW devices fabricated from these NW building blocks. Approximately hexagonal cross-section p/i/n coaxial NWs of various diameters (170-380 nm) were controllably synthesized by changing the Au catalyst diameter, which determines core diameter, as well as shell deposition time, which determines shell thickness. Measured polarization-resolved photocurrent spectra exhibit well-defined diameter-dependent peaks. The corresponding external quantum efficiency (EQE) spectra calculated from these data show good quantitative agreement with finite-difference time-domain (FDTD) simulations and allow assignment of the observed peaks to Fabry-Perot, whispering-gallery, and complex high-order resonant absorption modes. This comparison revealed a systematic red-shift of equivalent modes as a function of increasing NW diameter and a progressive increase in the number of resonances. In addition, tuning shell synthetic conditions to enable enhanced growth on select facets yielded NWs with approximately rectangular cross sections; analysis of transmission electron microscopy and scanning electron microscopy images demonstrate that growth of the n-type shell at 860 °C in the presence of phosphine leads to enhanced relative Si growth rates on the four {113} facets. Notably, polarization-resolved photocurrent spectra demonstrate that at longer wavelengths the rectangular cross-section NWs have narrow and significantly larger amplitude peaks with respect to similar size hexagonal NWs. A rectangular NW with a diameter of 260 nm yields a dominant mode centered at 570 nm with near-unity EQE in the transverse-electric polarized spectrum. Quantitative comparisons with FDTD simulations demonstrate that these new peaks arise from cavity modes with high symmetry that conform to the cross-sectional morphology of the rectangular NW, resulting in low optical loss of the mode. The ability to modulate absorption with changes in nanoscale morphology by controlled synthesis represents a promising route for developing new photovoltaic and optoelectronic devices. PMID:22889329

Kim, Sun-Kyung; Day, Robert W; Cahoon, James F; Kempa, Thomas J; Song, Kyung-Deok; Park, Hong-Gyu; Lieber, Charles M

2012-09-12

137

The influence of various core designs on stress distribution in the veneered zirconia crown: a finite element analysis study  

PubMed Central

PURPOSE The purpose of this study was to evaluate various core designs on stress distribution within zirconia crowns. MATERIALS AND METHODS Three-dimensional finite element models, representing mandibular molars, comprising a prepared tooth, cement layer, zirconia core, and veneer porcelain were designed by computer software. The shoulder (1 mm in width) variations in core were incremental increases of 1 mm, 2 mm and 3 mm in proximal and lingual height, and buccal height respectively. To simulate masticatory force, loads of 280 N were applied from three directions (vertical, at a 45° angle, and horizontal). To simulate maximum bite force, a load of 700 N was applied vertically to the crowns. Maximum principal stress (MPS) was determined for each model, loading condition, and position. RESULTS In the maximum bite force simulation test, the MPSs on all crowns observed around the shoulder region and loading points. The compressive stresses were located in the shoulder region of the veneer-zirconia interface and at the occlusal region. In the test simulating masticatory force, the MPS was concentrated around the loading points, and the compressive stresses were located at the 3 mm height lingual shoulder region, when the load was applied horizontally. MPS increased in the shoulder region as the shoulder height increased. CONCLUSION This study suggested that reinforced shoulder play an essential role in the success of the zirconia restoration, and veneer fracture due to occlusal loading can be prevented by proper core design, such as shoulder. PMID:23755346

Ha, Seung-Ryong; Kim, Sung-Hun; Yoo, Seung-Hyun; Jeong, Se-Chul; Lee, Jai-Bong; Yeo, In-Sung

2013-01-01

138

The Practical Turn in Teacher Education: Designing a Preparation Sequence for Core Practice Frames  

ERIC Educational Resources Information Center

Amid calls for more practice-based teacher education, this article presents a concrete illustration of a practice-based bridging strategy for preparing high school biology teachers to enact open-inquiry labs. Open-inquiry labs were considered a core practice frame that served as a context for identifying core practices and for giving coherence to…

Janssen, Fred; Westbroek, Hanna; Doyle, Walter

2014-01-01

139

Design study of an air pump and integral lift engine ALF-504 using the Lycoming 502 core  

NASA Technical Reports Server (NTRS)

Design studies were conducted for an integral lift fan engine utilizing the Lycoming 502 fan core with the final MQT power turbine. The fan is designed for a 12.5 bypass ratio and 1.25:1 pressure ratio, and provides supercharging for the core. Maximum sea level static thrust is 8370 pounds with a specific fuel consumption of 0.302 lb/hr-lb. The dry engine weight without starter is 1419 pounds including full-length duct and sound-attenuating rings. The engine envelope including duct treatment but not localized accessory protrusion is 53.25 inches in diameter and 59.2 inches long from exhaust nozzle exit to fan inlet flange. Detailed analyses include fan aerodynamics, fan and reduction gear mechanical design, fan dynamic analysis, engine noise analysis, engine performance, and weight analysis.

Rauch, D.

1972-01-01

140

Design of metallic textile core sandwich panels F.W. Zok *, H.J. Rathbun, Z. Wei, A.G. Evans  

E-print Network

Design of metallic textile core sandwich panels F.W. Zok *, H.J. Rathbun, Z. Wei, A.G. Evans-5050, USA Received 3 March 2003 Abstract Metallic sandwich panels with textile cores have been analyzed. All rights reserved. Keywords: Sandwich panels; Lightweight structures; Textiles; Optimal design 1

Zok, Frank

141

System design specification for rotary mode core sample trucks No. 2, 3, and 4 programmable logic controller  

SciTech Connect

The system this document describes controls several functions of the Core Sample Truck(s) used to obtain nuclear waste samples from various underground storage tanks at Hanford. The system will monitor the sampling process and provide alarms and other feedback to insure the sampling process is performed within the prescribed operating envelope. The intended audience for this document is anyone associated with rotary or push mode core sampling. This document describes the Alarm and Control logic installed on Rotary Mode Core Sample Trucks (RMCST) {number_sign}2, 3, and 4. It is intended to define the particular requirements of the RMCST alarm and control operation (not defined elsewhere) sufficiently for detailed design to implement on a Programmable Logic Controller (PLC).

Dowell, J.L.; Akers, J.C.

1995-12-31

142

Verification of the CENTRM Module for Adaptation of the SCALE Code to NGNP Prismatic and PBR Core Designs  

SciTech Connect

The generation of multigroup cross sections lies at the heart of the very high temperature reactor (VHTR) core design, whether the prismatic (block) or pebble-bed type. The design process, generally performed in three steps, is quite involved and its execution is crucial to proper reactor physics analyses. The primary purpose of this project is to develop the CENTRM cross-section processing module of the SCALE code package for application to prismatic or pebble-bed core designs. The team will include a detailed outline of the entire processing procedure for application of CENTRM in a final report complete with demonstration. In addition, they will conduct a thorough verification of the CENTRM code, which has yet to be performed. The tasks for this project are to: Thoroughly test the panel algorithm for neutron slowing down; Develop the panel algorithm for multi-materials; Establish a multigroup convergence 1D transport acceleration algorithm in the panel formalism; Verify CENTRM in 1D plane geometry; Create and test the corresponding transport/panel algorithm in spherical and cylindrical geometries; and, Apply the verified CENTRM code to current VHTR core design configurations for an infinite lattice, including assessing effectiveness of Dancoff corrections to simulate TRISO particle heterogeneity.

Ganapol, Barry; Maldonado, Ivan

2014-01-23

143

Thermal Hydraulics Design and Analysis Methodology for a Solid-Core Nuclear Thermal Rocket Engine Thrust Chamber  

NASA Technical Reports Server (NTRS)

Nuclear thermal propulsion is a leading candidate for in-space propulsion for human Mars missions. This chapter describes a thermal hydraulics design and analysis methodology developed at the NASA Marshall Space Flight Center, in support of the nuclear thermal propulsion development effort. The objective of this campaign is to bridge the design methods in the Rover/NERVA era, with a modern computational fluid dynamics and heat transfer methodology, to predict thermal, fluid, and hydrogen environments of a hypothetical solid-core, nuclear thermal engine the Small Engine, designed in the 1960s. The computational methodology is based on an unstructured-grid, pressure-based, all speeds, chemically reacting, computational fluid dynamics and heat transfer platform, while formulations of flow and heat transfer through porous and solid media were implemented to describe those of hydrogen flow channels inside the solid24 core. Design analyses of a single flow element and the entire solid-core thrust chamber of the Small Engine were performed and the results are presented herein

Wang, Ten-See; Canabal, Francisco; Chen, Yen-Sen; Cheng, Gary; Ito, Yasushi

2013-01-01

144

High Temperature Reactor (HTR) Deep Burn Core and Fuel Analysis: Design Selection for the Prismatic Block Reactor  

SciTech Connect

The Deep Burn (DB) Project is a U.S. Department of Energy sponsored feasibility study of Transuranic Management using high burnup fuel in the high temperature helium cooled reactor (HTR). The DB Project consists of seven tasks: project management, core and fuel analysis, spent fuel management, fuel cycle integration, TRU fuel modeling, TRU fuel qualification, and HTR fuel recycle. In the Phase II of the Project, we conducted nuclear analysis of TRU destruction/utilization in the HTR prismatic block design (Task 2.1), deep burn fuel/TRISO microanalysis (Task 2.3), and synergy with fast reactors (Task 4.2). The Task 2.1 covers the core physics design, thermo-hydraulic CFD analysis, and the thermofluid and safety analysis (low pressure conduction cooling, LPCC) of the HTR prismatic block design. The Task 2.3 covers the analysis of the structural behavior of TRISO fuel containing TRU at very high burnup level, i.e. exceeding 50% of FIMA. The Task 4.2 includes the self-cleaning HTR based on recycle of HTR-generated TRU in the same HTR. Chapter IV contains the design and analysis results of the 600MWth DB-HTR core physics with the cycle length, the average discharged burnup, heavy metal and plutonium consumptions, radial and axial power distributions, temperature reactivity coefficients. Also, it contains the analysis results of the 450MWth DB-HTR core physics and the analysis of the decay heat of a TRU loaded DB-HTR core. The evaluation of the hot spot fuel temperature of the fuel block in the DB-HTR (Deep-Burn High Temperature Reactor) core under full operating power conditions are described in Chapter V. The investigated designs are the 600MWth and 460MWth DB-HTRs. In Chapter VI, the thermo-fluid and safety of the 600MWth DB-HTRs has been analyzed to investigate a thermal-fluid design performance at the steady state and a passive safety performance during an LPCC event. Chapter VII describes the analysis results of the TRISO fuel microanalysis of the 600MWth and 450MWth DB-HTRs. The TRISO fuel microanalysis covers the gas pressure buildup in a coated fuel particle including helium production, the thermo-mechanical behavior of a CFP, the failure probabilities of CFPs, the temperature distribution in a CPF, and the fission product (FP) transport in a CFP and a graphite. In Chapter VIII, it contains the core design and analysis of sodium cooled fast reactor (SFR) with deep burn HTR reactor. It considers a synergistic combination of the DB-MHR and an SFR burner for a safe and efficient transmutation of the TRUs from LWRs. Chapter IX describes the design and analysis results of the self-cleaning (or self-recycling) HTR core. The analysis is considered zero and 5-year cooling time of the spent LWR fuels.

Francesco Venneri; Chang-Keun Jo; Jae-Man Noh; Yonghee Kim; Claudio Filippone; Jonghwa Chang; Chris Hamilton; Young-Min Kim; Ji-Su Jun; Moon-Sung Cho; Hong-Sik Lim; MIchael A. Pope; Abderrafi M. Ougouag; Vincent Descotes; Brian Boer

2010-09-01

145

Design and evaluation of low latency interconnection networks for real-time many-core embedded systems  

Microsoft Academic Search

On-chip interconnection networks (OCINs) in many-core embedded systems consume large portions of the chip’s area, cost, delay and power. In addition to competing in area, cost, and power, OCINs must feature low diameters to meet real time deadlines. To achieve these goals, designing low-latency networks and sharing network resources are essential. We explore 13 OCINs – some are new such

Fadi N. Sibai

146

Design of Gas-phase Synthesis of Core-Shell Particles by Computational Fluid – Aerosol Dynamics  

PubMed Central

Core-shell particles preserve the bulk properties (e.g. magnetic, optical) of the core while its surface is modified by a shell material. Continuous aerosol coating of core TiO2 nanoparticles with nanothin silicon dioxide shells by jet injection of hexamethyldisiloxane precursor vapor downstream of titania particle formation is elucidated by combining computational fluid and aerosol dynamics. The effect of inlet coating vapor concentration and mixing intensity on product shell thickness distribution is presented. Rapid mixing of the core aerosol with the shell precursor vapor facilitates efficient synthesis of hermetically coated core-shell nanoparticles. The predicted extent of hermetic coating shells is compared to the measured photocatalytic oxidation of isopropanol by such particles as hermetic SiO2 shells prevent the photocatalytic activity of titania. Finally the performance of a simpler, plug-flow coating model is assessed by comparisons to the present detailed CFD model in terms of coating efficiency and silica average shell thickness and texture. PMID:23729817

Buesser, B.; Pratsinis, S.E.

2013-01-01

147

Possible Methods to Estimate Core Location in a Beyond-Design-Basis Accident at a GE BWR with a Mark I Containment Stucture  

SciTech Connect

It is difficult to track to the location of a melted core in a GE BWR with Mark I containment during a beyond-design-basis accident. The Cooper Nuclear Station provided a baseline of normal material distributions and shielding configurations for the GE BWR with Mark I containment. Starting with source terms for a design-basis accident, methods and remote observation points were investigated to allow tracking of a melted core during a beyond-design-basis accident. The design of the GE BWR with Mark-I containment highlights an amazing poverty of expectations regarding a common mode failure of all reactor core cooling systems resulting in a beyond-design-basis accident from the simple loss of electric power. This design is shown in Figure 1. The station blackout accident scenario has been consistently identified as the leading contributor to calculated probabilities for core damage. While NRC-approved models and calculations provide guidance for indirect methods to assess core damage during a beyond-design-basis loss-of-coolant accident (LOCA), there appears to be no established method to track the location of the core directly should the LOCA include a degree of fuel melt. We came to the conclusion that - starting with detailed calculations which estimate the release and movement of gaseous and soluble fission products from the fuel - selected dose readings in specific rooms of the reactor building should allow the location of the core to be verified.

Walston, S; Rowland, M; Campbell, K

2011-07-27

148

Design of 154 kV class 100 MVA 3 phase HTS transformer on a common magnetic core  

NASA Astrophysics Data System (ADS)

We have proposed a high temperature superconducting (HTS) transformer which can substitute for a conventional oil transformer for power distribution in Korea. The conventional transformer is composed of three identical single phase transformers because of the limitations on volume and weight. Now the Korean power company has started to consider the possibility of a transformer on a common magnetic core because it can be a solution for the increment of capacity without new construction of substations. In this paper, we proposed an HTS transformer on a common core. Its capacity is the same as the previous HTS transformer, which was 100 MVA, 154 kV/22.9 kV. The former is smaller and lighter than the latter. We assumed a transformer tank which covers the common core and windings. The tank also acts as a vacuum seal for a cooling system and so the cryostats for the windings do not need to have vacuum layers. The design parameters are compared with those of both a conventional one and an HTS transformer with separate cores.

Choi, J.; Lee, S.; Park, M.; Kim, W.; Kim, S.; Han, J.; Lee, H.; Choi, K.

2007-10-01

149

Effective Web Design and Core Communication Issues: The Missing Components in Web-Based Distance Education.  

ERIC Educational Resources Information Center

Discussion of Web-based distance education focuses on communication issues. Highlights include Internet communications; components of a Web site, including site architecture, user interface, information delivery method, and mode of feedback; elements of Web design, including conceptual design, sensory design, and reactive design; and a Web…

Burch, Randall O.

2001-01-01

150

Design and fabrication of the iron core for the OHTE experimental machine  

Microsoft Academic Search

The Ohmically Heated Toroidal Experiment (OHTE) is a toroidal pinch magnetic confinement plasma experiment which has been operating at GA Technologies (GA) since February 1981. In its original form, plasma current was induced by an air core induction or ohmic heating coil driven by a capacitor bank. Preliminary study revealed that greater plasma currents and pulse lengths could be achieved

B. Curwen; L. H. Franklin

1983-01-01

151

Three pass core design proposal for a high performance light water reactor  

Microsoft Academic Search

The paper describes a novel core concept for a nuclear reactor cooled with supercritical water, in which the coolant is heated up from 280°C at the reactor inlet to 500°C at the outlet in four steps: a first heat-up step is provided by heat transfer from fuel assemblies to the moderator water in gaps and moderator boxes, a second step

T. Schulenberg; J. Starflinger; J. Heinecke

2008-01-01

152

Optimal core shape design for cogging torque reduction of brushless DC motor using genetic algorithm  

Microsoft Academic Search

The cogging torque in the small brushless DC (BLDC) motors used in the digital versatile disk (DVD) driving system or hard disk drive (HDD) system can cause some serious vibration problems. In this paper, some core shapes that reduce cogging torque are found by using the reluctance network method (RNM) for magnetic field analysis and genetic algorithms (GAs) for optimization.

Ki-Jin Han; Han-Sam Cho; Dong-Hyeok Cho; Hyun-Kyo Jung

2000-01-01

153

A Core-Theoretic Solution for the Design of Cooperative Agreements on Transfrontier Pollution  

Microsoft Academic Search

For a simple economic model of transfrontier pollution, widely used in theoretical studies of international treaties bearing on joint abatement, we offer in this paper a scheme for sharing national abatement costs through international financial transfers that is inspired by a classical solution concept from the theory of cooperative games?namely, the core of a game. The scheme has the following

Parkash Chander; Henry Tulkens

1994-01-01

154

A core-theoretic solution for the design of cooperative agreements on transfrontier pollution  

Microsoft Academic Search

For a simple economic model of transfrontier pollution, widely used in theoretical studies of international treaties bearing on joint abatement, we offer in this paper a scheme for sharing national abatement costs through international financial transfers that is inspired by a classical solution concept from the theory of cooperative games—namely, the core of a game. The scheme has the following

Parkash Chander; Henry Tulkens

1995-01-01

155

The Common Core of a Child Care Center. Child Care Facility Design.  

ERIC Educational Resources Information Center

Examines the notion of an early childhood education center organized as a series of houses around a common core of shared facilities. Discusses examples of child-care centers in Sweden and explores ideas that can promote functional facilities. Suggestions include ideas about physical-motor activities areas, administration offices, centralized…

Moore, Gary T.

1997-01-01

156

Evaluation of the Effect of Different Ferrule Designs on Fracture Resistance of Maxillary Incisors Restored with Bonded Posts and Cores  

PubMed Central

Introduction: In cases of severe hard tissue loss, 2 mm circumferential ferrule is difficult to achieve. So in these cases we should use different ferrule designs. This in vitro study investigated the effect of different ferrule designs on the fracture resistance of teeth restored with bonded post and cores. Materials and Methods: Forty freshly-extracted central incisors were endodontically treated. The teeth were randomly divided into four groups; group 1 were teeth with 2 mm circumferential ferrule above the CEJ, group 2 were teeth with 2 mm ferrule only on the palatal side of the teeth, group 3 consisted of teeth with 2 mm ferrule only on the facial side and group 4 were teeth with 2 mm ferrule on the palatal and facial side of teeth with interproximal concavities. All teeth were restored with fiber posts and composite cores. The specimen was mounted on a universal testing machine and compressive load was applied to the long axis of the specimen until failure occurred. Results: The fracture resistance was 533.79 ± 232.28 in group 1, 634.75± 133.35 in group 2, 828.90 ±118.27 in group 3 and 678.78± 160.20 in group 4. The post hoc analysis showed statistically significant difference between groups 1 and 3. Conclusions: The results of this in vitro study showed that facial ferrule increases the fracture resistance of endodontically treated teeth restored with bonded post and cores. PMID:21998789

Mahdavi Izadi, Z.; Jalalian, E.; Eyvaz Ziaee, A.; Zamani, L.; Javanshir, B.

2010-01-01

157

CANADIAN RISK MANAGEMENT PROGRAM (CRM) The CRM designation is awarded to students who have successfully completed the three core courses in Risk  

E-print Network

CANADIAN RISK MANAGEMENT PROGRAM (CRM) The CRM designation is awarded to students who have successfully completed the three core courses in Risk Management. These core courses also comprise the Risk Management major for the Fellow-Chartered Insurance Professional (FCIP/FIIC) RISK MANAGEMENT COURSES: · Risk

Martin, Jeff

158

Space Station Furnace Facility Core. Requirements definition and conceptual design study. Volume 2: Technical report. Appendix 6: Technical summary reports  

NASA Astrophysics Data System (ADS)

The Space Station Furnace Facility (SSFF) is a modular facility for materials research in the microgravity environment of the Space Station Freedom (SSF). The SSFF is designed for crystal growth and solidification research in the fields of electronic and photonic materials, metals and alloys, and glasses and ceramics and will allow for experimental determination of the role of gravitational forces in the solidification process. The facility will provide a capability for basic scientific research and will evaluate the commercial viability of low-gravity processing of selected technologically important materials. The facility is designed to support a complement of furnace modules as outlined in the Science Capabilities Requirements Document (SCRD). The SSFF is a three rack facility that provides the functions, interfaces, and equipment necessary for the processing of the furnaces and consists of two main parts: the SSFF Core Rack and the two Experiment Racks. The facility is designed to accommodate two experimenter-provided furnace modules housed within the two experiment racks, and is designed to operate these two furnace modules simultaneously. The SCRD specifies a wide range of furnace requirements and serves as the basis for the SSFF conceptual design. SSFF will support automated processing during the man-tended operations and is also designed for crew interface during the permanently manned configuration. The facility is modular in design and facilitates changes as required, so the SSFF is adept to modifications, maintenance, reconfiguration, and technology evolution.

1992-05-01

159

Space Station Furnace Facility Core. Requirements definition and conceptual design study. Volume 2: Technical report. Appendix 6: Technical summary reports  

NASA Technical Reports Server (NTRS)

The Space Station Furnace Facility (SSFF) is a modular facility for materials research in the microgravity environment of the Space Station Freedom (SSF). The SSFF is designed for crystal growth and solidification research in the fields of electronic and photonic materials, metals and alloys, and glasses and ceramics and will allow for experimental determination of the role of gravitational forces in the solidification process. The facility will provide a capability for basic scientific research and will evaluate the commercial viability of low-gravity processing of selected technologically important materials. The facility is designed to support a complement of furnace modules as outlined in the Science Capabilities Requirements Document (SCRD). The SSFF is a three rack facility that provides the functions, interfaces, and equipment necessary for the processing of the furnaces and consists of two main parts: the SSFF Core Rack and the two Experiment Racks. The facility is designed to accommodate two experimenter-provided furnace modules housed within the two experiment racks, and is designed to operate these two furnace modules simultaneously. The SCRD specifies a wide range of furnace requirements and serves as the basis for the SSFF conceptual design. SSFF will support automated processing during the man-tended operations and is also designed for crew interface during the permanently manned configuration. The facility is modular in design and facilitates changes as required, so the SSFF is adept to modifications, maintenance, reconfiguration, and technology evolution.

1992-01-01

160

Design of communications model in double systems based on multi-core platform  

Microsoft Academic Search

Aiming at the problem of data transfer for virtual-machine monitor in device access, a communications mode in double systems based on multi-core processor is proposed. Two key problem in this mode buffer overflow and package pseudo loss are analyzed, communications mechanism based on Inter-processor interrupts and shared memory is constructed, data transfer between virtual-machine monitor and IO process machine is

Xiaorui Wang; Yudong Guo; Weiyu Dong; Yong Li; Guang Shi; Xian Yu

2010-01-01

161

Multiple prostate cancer cores with different Gleason grades submitted in the same specimen container without specific site designation: should each core be assigned an individual Gleason score?  

PubMed

To better represent the Gleason score of radical prostatectomy, the International Society of Urologic Pathologists Consensus Committee recommends assigning individual Gleason scores to prostate cancer cores submitted in separate containers and/or multiple cores in the same container with site identifiers. However, scenarios where multiple cores are submitted in the same container without site identifiers or labeled "left/right" are common. To assess this scenario, we analyzed 110 extended biopsies containing different Gleason scores with corresponding radical prostatectomy for clinically significant grade differences. Because cores are individually labeled and submitted at our institution, we simulated a scenario of multiple intact cores with different Gleason scores in the same container(s) by analyzing as if submitted in containers labeled "left/right." For each biopsy, a Global (all positive cores averaged as 1 long positive core), Worst, and Largest tumor volume Gleason score was determined and compared with grade of radical prostatectomy using kappa statistics. Biopsies containing core(s) with 3+4 and other core(s) 3+3 were excluded because in this situation, both Global and Worst Gleason score will be always 3+4. The following scenarios were considered clinically significant upgrading: biopsy Gleason score 6 / 3+4 to radical prostatectomy 4+3; biopsy 7 to radical prostatectomy 8-10; biopsy 7 to radical prostatectomy 7 with tertiary Gleason pattern 5. Overall, 51 cases met inclusion criteria. Biopsy Worst Gleason score had the best correlation with radical prostatectomy (kappa agreement of 0.37). Clinically significant upgrading at radical prostatectomy was least with Worst (4%) and highest with Global Gleason score (37%). Upgrading and downgrading were noted in 14% and 8%, respectively, of 59 cases containing core(s) with a Gleason score of 3+4 and other core(s) 3+3, suggesting that any amount of higher Gleason pattern should be recorded. When multiple intact cores are submitted in the same container without specific identifiers, individual cores with cancer should be graded and/or the Worst Gleason score should be recorded. PMID:19144380

Kunju, Lakshmi P; Daignault, Stephanie; Wei, John T; Shah, Rajal B

2009-04-01

162

Thermal hydraulic method for whole core design analysis of an HTGR  

SciTech Connect

A new thermal hydraulic method and initial results are presented for core-wide steady state analysis of prismatic High Temperature Gas-Cooled Reactors (HTGR). The method allows for the complete solution of temperature and coolant mass flow distribution by solving quasi-steady energy balances for the discretized core. Assembly blocks are discretized into unit cells for which the average temperature of each unit cell is determined. Convective heat removal is coupled to the unit cell energy balances by a 1-D axial flow model. The flow model uses established correlations for friction factor and Nusselt number. Bypass flow is explicitly calculated by using an initial guess for mass flow distribution and determining the exit pressure of each flow channel. The mass flow distribution is updated until a uniform core exit pressure condition is reached. Results are obtained for the MHTGR-350 with emphasis on the change in thermal hydraulic parameters due to various steady state power profiles and bypass gap widths. Steady state temperature distribution and its variations are discussed. (authors)

Huning, A. J.; Garimella, S. [George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA (United States)

2013-07-01

163

Designed fabrication and characterization of three-dimensionally ordered arrays of core-shell magnetic mesoporous carbon microspheres.  

PubMed

A confined interface coassembly coating strategy based on three-dimensional (3-D) ordered macroporous silica as the nanoreactor was demonstrated for the designed fabrication of novel 3-D ordered arrays of core-shell microspheres consisting of Fe3O4 cores and ordered mesoporous carbon shells. The obtained 3-D ordered arrays of Fe3O4@mesoporous carbon materials possess two sets of periodic structures at both mesoscale and submicrometer scale, high surface area of 326 m(2)/g, and large mesopore size of 19 nm. Microwave absorption test reveals that the obtained materials have excellent microwave absorption performances with maximum reflection loss of up to -57 dB at 8 GHz, and large absorption bandwidth (7.3-13.7 GHz, < -10 dB), due to the combination of the large magnetic loss from iron oxides, the strong dielectric loss from carbonaceous shell, and the strong reflection and scattering of electromagnetic waves of the ordered structures of the mesopores and 3-D arrays of core-shell microspheres. PMID:25647306

Yuan, Kaiping; Che, Renchao; Cao, Qi; Sun, Zhenkun; Yue, Qin; Deng, Yonghui

2015-03-11

164

GPU Based General-Purpose Parallel computing to Solve Nuclear Reactor In-Core fuel Management Design and Operation Problem  

SciTech Connect

In-core fuel management study is a crucial activity in nuclear power plant design and operation. Its common problem is to find an optimum arrangement of fuel assemblies inside the reactor core. Main objective for this activity is to reduce the cost of generating electricity, which can be done by altering several physical properties of the nuclear reactor without violating any of the constraints imposed by operational and safety considerations. This research try to address the problem of nuclear fuel arrangement problem, which is, leads to the multi-objective optimization problem. However, the calculation of the reactor core physical properties itself is a heavy computation, which became obstacle in solving the optimization problem by using genetic algorithm optimization.This research tends to address that problem by using the emerging General Purpose Computation on Graphics Processing Units (GPGPU) techniques implemented by C language for CUDA (Compute Unified Device Architecture) parallel programming. By using this parallel programming technique, we develop parallelized nuclear reactor fitness calculation, which is involving numerical finite difference computation. This paper describes current prototype of the parallel algorithm code we have developed on CUDA, that performs one hundreds finite difference calculation for nuclear reactor fitness evaluation in parallel by using GPU G9 Hardware Series developed by NVIDIA.

Prayudhatama, D.; Waris, A.; Kurniasih, N.; Kurniadi, R. [Bosscha Laboratory, Department of Physics, Nuclear Physics and Biophysics Research Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung (Indonesia)

2010-06-22

165

Very High Temperature Reactor (VHTR) Deep Burn Core and Fuel Analysis -- Complete Design Selection for the Pebble Bed Reactor  

SciTech Connect

The Deep-Burn (DB) concept focuses on the destruction of transuranic nuclides from used light water reactor fuel. These transuranic nuclides are incorporated into TRISO coated fuel particles and used in gas-cooled reactors with the aim of a fractional fuel burnup of 60 to 70% in fissions per initial metal atom (FIMA). This high performance is expected through the use of multiple recirculation passes of the fuel in pebble form without any physical or chemical changes between passes. In particular, the concept does not call for reprocessing of the fuel between passes. In principle, the DB pebble bed concept employs the same reactor designs as the presently envisioned low-enriched uranium core designs, such as the 400 MWth Pebble Bed Modular Reactor (PBMR-400). Although it has been shown in the previous Fiscal Year (2009) that a PuO2 fueled pebble bed reactor concept is viable, achieving a high fuel burnup, while remaining within safety-imposed prescribed operational limits for fuel temperature, power peaking and temperature reactivity feedback coefficients for the entire temperature range, is challenging. The presence of the isotopes 239-Pu, 240-Pu and 241-Pu that have resonances in the thermal energy range significantly modifies the neutron thermal energy spectrum as compared to a ”standard,” UO2-fueled core. Therefore, the DB pebble bed core exhibits a relatively hard neutron energy spectrum. However, regions within the pebble bed that are near the graphite reflectors experience a locally softer spectrum. This can lead to power and temperature peaking in these regions. Furthermore, a shift of the thermal energy spectrum with increasing temperature can lead to increased absorption in the resonances of the fissile Pu isotopes. This can lead to a positive temperature reactivity coefficient for the graphite moderator under certain operating conditions. The effort of this task in FY 2010 has focused on the optimization of the core to maximize the pebble discharge burnup level, while retaining its inherent safety characteristics. Using generic pebble bed reactor cores, this task will perform physics calculations to evaluate the capabilities of the pebble bed reactor to perform utilization and destruction of LWR used-fuel transuranics. The task will use established benchmarked models, and will introduce modeling advancements appropriate to the nature of the fuel considered (high TRU content and high burn-up).

B. Boer; A. M. Ougouag

2010-09-01

166

Design and optimization of liquid core optical ring resonator for refractive index sensing  

NASA Astrophysics Data System (ADS)

This study performs a detailed theoretical analysis of refractive index (RI) sensors based on whispering gallery modes (WGMs) in liquid core optical ring resonators (LCORRs). Both TE- and TM-polarized WGMs of various orders are considered. The analysis shows that WGMs of higher orders need thicker walls to achieve a near-zero thermal drift, but WGMs of different orders exhibit a similar RI sensing performance at the thermostable wall thicknesses. The RI detection limit is very low at the thermostable thickness. The theoretical predications should provide a general guidance in the development of LCORR-based thermostable RI sensors.

Lin, Nai; Jiang, Lan; Wang, Sumei; Xiao, Hai; Lu, Yongfeng; Tsai, Hai-Lung

2011-07-01

167

Design and optimization of liquid core optical ring resonator for refractive index sensing.  

PubMed

This study performs a detailed theoretical analysis of refractive index (RI) sensors based on whispering gallery modes (WGMs) in liquid core optical ring resonators (LCORRs). Both TE- and TM-polarized WGMs of various orders are considered. The analysis shows that WGMs of higher orders need thicker walls to achieve a near-zero thermal drift, but WGMs of different orders exhibit a similar RI sensing performance at the thermostable wall thicknesses. The RI detection limit is very low at the thermostable thickness. The theoretical predications should provide a general guidance in the development of LCORR-based thermostable RI sensors. PMID:21743574

Lin, Nai; Jiang, Lan; Wang, Sumei; Xiao, Hai; Lu, Yongfeng; Tsai, Hai-Lung

2011-07-10

168

Staying True to the Core: Designing the Future Academic Library Experience  

ERIC Educational Resources Information Center

In 2014, the practice of user experience design in academic libraries continues to evolve. It is typically applied in the context of interactions with digital interfaces. Some academic librarians are applying user experience approaches more broadly to design both environments and services with human-centered strategies. As the competition for the…

Bell, Steven J.

2014-01-01

169

Design tunable materials: Ferroelectric-antiferroelectric composite with core-shell structure  

NASA Astrophysics Data System (ADS)

Permittivity, tunability, and ferroelectric properties can be tailored to meet specific requirements for applications by combining ferroelectric (BaTiO3-BT) and antiferroelectric (La0.04Pb0.96Ti0.1Zr0.9O3-PLZT) and by exploiting interdiffusion and grain size effects at nanoscale. The dielectric properties, dc-tunability, and P(E) loops of ferroelectric-antiferroelectric nanostructured composites produced from mechanically mixed powders (PLZT-BT) and from core-shell particles (PLZT@BT) were comparatively analyzed. Interdiffusion accompanied by local composition gradients occurred during sintering of PLZT@BT composites and caused a thermally stable permittivity. Permittivity was reduced below 1000 in both cases (900 for PLZT-BT and 290 for PLZT@BT), while preserving tunability to 1.2-1.4 (E = 40 kV/cm), with a linear field dependence.

Curecheriu, Lavinia-Petronela; Buscaglia, Maria Teresa; Maglia, Filippo; Anselmi-Tamburini, Umberto; Buscaglia, Vincenzo; Mitoseriu, Liliana

2014-12-01

170

Conceptual Design and Feasibility of Foil Bearings for Rotorcraft Engines: Hot Core Bearings  

NASA Technical Reports Server (NTRS)

Recent developments in gas foil bearing technology have led to numerous advanced high-speed rotating system concepts, many of which have become either commercial products or experimental test articles. Examples include oil-free microturbines, motors, generators and turbochargers. The driving forces for integrating gas foil bearings into these high-speed systems are the benefits promised by removing the oil lubrication system. Elimination of the oil system leads to reduced emissions, increased reliability, and decreased maintenance costs. Another benefit is reduced power plant weight. For rotorcraft applications, this would be a major advantage, as every pound removed from the propulsion system results in a payload benefit.. Implementing foil gas bearings throughout a rotorcraft gas turbine engine is an important long-term goal that requires overcoming numerous technological hurdles. Adequate thrust bearing load capacity and potentially large gearbox applied radial loads are among them. However, by replacing the turbine end, or hot section, rolling element bearing with a gas foil bearing many of the above benefits can be realized. To this end, engine manufacturers are beginning to explore the possibilities of hot section gas foil bearings in propulsion engines. This overview presents a logical follow-on activity by analyzing a conceptual rotorcraft engine to determine the feasibility of a foil bearing supported core. Using a combination of rotordynamic analyses and a load capacity model, it is shown to be reasonable to consider a gas foil bearing core section. In addition, system level foil bearing testing capabilities at NASA Glenn Research Center are presented along with analysis work being conducted under NRA Cooperative Agreements.

Howard, Samuel A.

2007-01-01

171

Genomic Design of Strong Direct-Gap Optical Transition in Si/Ge Core/Multishell Nanowires  

SciTech Connect

Finding a Si-based material with strong optical activity at the band-edge remains a challenge despite decades of research. The interest lies in combining optical and electronic functions on the same wafer, while retaining the extraordinary know-how developed for Si. However, Si is an indirect-gap material. The conservation of crystal momentum mandates that optical activity at the band-edge includes a phonon, on top of an electron-hole pair, and hence photon absorption and emission remain fairly unlikely events requiring optically rather thick samples. A promising avenue to convert Si-based materials to a strong light-absorber/emitter is to combine the effects on the band-structure of both nanostructuring and alloying. The number of possible configurations, however, shows a combinatorial explosion. Furthermore, whereas it is possible to readily identify the configurations that are formally direct in the momentum space (due to band-folding) yet do not have a dipole-allowed transition at threshold, the problem becomes not just calculation of band structure but also calculation of absorption strength. Using a combination of a genetic algorithm and a semiempirical pseudopotential Hamiltonian for describing the electronic structures, we have explored hundreds of thousands of possible coaxial core/multishell Si/Ge nanowires with the orientation of [001], [110], and [111], discovering some 'magic sequences' of core followed by specific Si/Ge multishells, which can offer both a direct bandgap and a strong oscillator strength. The search has revealed a few simple design principles: (i) the Ge core is superior to the Si core in producing strong bandgap transition; (ii) [001] and [110] orientations have direct bandgap, whereas the [111] orientation does not; (iii) multishell nanowires can allow for greater optical activity by as much as an order of magnitude over plain nanowires; (iv) the main motif of the winning configurations giving direct allowed transitions involves rather thin Si shell embedded within wide Ge shells. We discuss the physical origin of the enhanced optical activity, as well as the effect of possible experimental structural imperfections on optical activity in our candidate core/multishell nanowires.

Zhang, L.; d'Avezac, M.; Luo, J. W.; Zunger, A.

2012-02-08

172

Design of the Core Stage Inter-Tank Umbilical {CSITU) Compliance Mechanism  

NASA Technical Reports Server (NTRS)

Project Goals: a) Design the compliance mechanism for the CSITU system to a 30% level -3D models completed in Pro/Engineer -Relevant design analysis b) Must meet all system requirements and establish basis for proceeding with detailed design. Tasks to be completed: A design that meets requirements for the 30% design review, 01/16/2013. Umbilical arms provide commodities to the launch vehicle prior to T-0. Commodities can range anywhere from hydraulics, pneumatics, cryogenic, electrical, ECS, etc ... Umbilicals commonly employ truss structures to deliver commodities to vehicle. Common configurations include: -Tilt-up -Swing Arm -Hose Drape -Drop Arm Umbilical arms will be mounted to Mobile Launch Platform. SLS currently has 9 T-0 umbilical arms. The compliance refers to the ability of the umbilical to adjust to minor changes in vehicle location. The compliance mechanism refers to the mechanism on the ground support equipment {GSE) that compensates for these changes. For the CSITU, these minor changes, or vehicle excursions, can be up to +4 in. Excursions refer to movements of the vehicle caused by wind loads and thermal expansion. It is ideal to have significant vertical compliance so a passive secondary release mechanism may be implemented.

Smith, Kurt R.

2013-01-01

173

Core design and reactor physics of a breed and burn gas-cooled fast reactor  

E-print Network

In order to fulfill the goals set forth by the Generation IV International Forum, the current NERI funded research has focused on the design of a Gas-cooled Fast Reactor (GFR) operating in a Breed and Burnm (B&B) fuel cycle ...

Yarsky, Peter

2005-01-01

174

Design of narrow band-pass filters based on the resonant-tunneling phenomenon in multi-core photonic crystal fibers.  

PubMed

The objective of the present paper is to introduce and numerically demonstrate the operation of a novel band-pass filter based on the phenomenon of resonant tunneling inmulti-core photonic crystal fibers (PCFs). The proposed PCF consists of two identical cores separated by a third one which acts as a resonator. With a fine adjustment of the design parameters associated with the resonant-core, phase matching at a single wavelength can be achieved, thus enabling very narrow-band resonant directional coupling between the input and the output cores. The validation of the design is ensured with an accurate PCF analysis based on finite element and beam propagation algorithms. The proposed narrow band-pass filter can be employed in various applications such as all fiber and pass/bandstop filtering. PMID:19503248

Saitoh, Kunimasa; Florous, Nikolaos J; Koshiba, Masanori; Skorobogatiy, Maksim

2005-12-12

175

Design of narrow band-pass filters based on the resonant-tunneling phenomenon in multi-core photonic crystal fibers  

NASA Astrophysics Data System (ADS)

The objective of the present paper is to introduce and numerically demonstrate the operation of a novel band-pass filter based on the phenomenon of resonant tunneling inmulti-core photonic crystal fibers (PCFs). The proposed PCF consists of two identical cores separated by a third one which acts as a resonator. With a fine adjustment of the design parameters associated with the resonant-core, phase matching at a single wavelength can be achieved, thus enabling very narrow-band resonant directional coupling between the input and the output cores. The validation of the design is ensured with an accurate PCF analysis based on finite element and beam propagation algorithms. The proposed narrow band-pass filter can be employed in various applications such as all fiber and pass/bandstop filtering.

Saitoh, Kunimasa; Florous, Nikolaos J.; Koshiba, Masanori; Skorobogatiy, Maksim

2005-12-01

176

The Neutronics Design and Analysis of a 200MW(electric) Simplified Boiling Water Reactor Core  

Microsoft Academic Search

A 200-MW(electric) simplified boiling water reactor (SBWR) was designed and analyzed under sponsorship of the U.S. Department of Energy Nuclear Energy Research Initiative program. The compact size of a 200-MW(electric) reactor makes it attractive for countries with a less well developed engineering infrastructure, as well as for developed countries seeking to tailor generation capacity more closely to the growth of

Daniel R. Tinkler; Thomas J. Downar

2003-01-01

177

The performance of 3500 MWth homogeneous and heterogeneous metal fueled core designs  

SciTech Connect

Performance parameters are calculated for a representative 3500 MWth homogeneous and a heterogeneous metal fueled reactor design. The equilibrium cycle neutronic characteristics, safety coefficients, control system requirements, and control rod worths are evaluated. The thermal-hydraulic characteristics for both configurations are also compared. The heavy metal fuel loading requirements and neutronic performance characteristics are also evaluated for the uranium startup option. 14 refs., 14 figs., 20 tabs.

Turski, R.; Yang, Shi-tien

1987-11-01

178

OECD MCCI project long-term 2-D molten core concrete interaction test design report, Rev. 0. September 30, 2002.  

SciTech Connect

The Melt Attack and Coolability Experiments (MACE) program at Argonne National Laboratory addressed the issue of the ability of water to cool and thermally stabilize a molten core-concrete interaction when the reactants are flooded from above. These tests provided data regarding the nature of corium interactions with concrete, the heat transfer rates from the melt to the overlying water pool, and the role of noncondensable gases in the mixing processes that contribute to melt quenching. As a follow-on program to MACE, The Melt Coolability and Concrete Interaction Experiments (MCCI) project is conducting reactor material experiments and associated analysis to achieve the following two technical objectives: (1) resolve the ex-vessel debris coolability issue through a program that focuses on providing both confirmatory evidence and test data for the coolability mechanisms identified in MACE integral effects tests, and (2) address remaining uncertainties related to long-term two-dimensional molten core-concrete interactions under both wet and dry cavity conditions. Achievement of these two objectives will demonstrate the efficacy of severe accident management guidelines for existing plants, and provide the technical basis for better containment designs for future plants. In terms of the first program objective, the Small-Scale Water Ingression and Crust Strength (SSWICS) test series has been initiated to provide fundamental information on the ability of water to ingress into cracks and fissures that form in the debris during quench, thereby augmenting the otherwise conduction-limited heat transfer process. A test plan for Melt Eruption Separate Effects Tests (MESET) has also been developed to provide information on the extent of crust growth and melt eruptions as a function of gas sparging rate under well-controlled experiment conditions. In terms of the second program objective, the project Management Board (MB) has approved startup activities required to carry out experiments to address remaining uncertainties related to long-term two-dimensional molten core-concrete interaction. In particular, for both wet and dry cavity conditions, there is uncertainty insofar as evaluating the lateral vs. axial power split during a core-concrete interaction due to a lack of experiment data. As a result, there are differences in the 2-D cavity erosion predicted by codes such as MELCOR, WECHSL, and COSACO. The first step towards generating this data is to produce a test plan for review by the Project Review Group (PRG). The purpose of this document is to provide this plan.

Farmer, M. T.; Kilsdonk, D. J.; Lomperski, S.; Aeschliman, R. W.; Basu, S. (Nuclear Engineering Division); (NRC)

2011-05-23

179

Design of an Efficient Out-of-Core Read Alignment Algorithm  

Microsoft Academic Search

\\u000a New genome sequencing technologies are poised to enter the sequencing landscape with significantly higher throughput of read\\u000a data produced at unprecedented speeds and lower costs per run. However, current in-memory methods to align a set of reads to one or more reference genomes are ill-equipped to handle the expected growth of read-throughput\\u000a from newer technologies.\\u000a \\u000a \\u000a This paper reports the design

Arun S. Konagurthu; Lloyd Allison; Thomas Conway; Bryan Beresford-Smith; Justin Zobel

2010-01-01

180

ITER Core Imaging X-Ray Spectrometer Conceptual Design and Performance Assessment - Phase 2  

SciTech Connect

During Phase 2 of our study of the CIXS conceptual design we have tackled additional important issues that are unique to the ITER environment. These include the thermal control of the crystal and detector enclosures located in an environment with a 100-250 C ambient temperature, tritium containment, and the range of crystal and detector movement based on the need for spectral adjustments and the desire to make measurements of colder plasmas. In addressing these issues we have selected a ''Dewar''-type enclosure for the crystals and detectors. Applying realistic view factors for radiant heat and making allowance for conduction we have made engineering studies of this enclosure and showed that the cooling requirements can be solved and the temperature can be kept sufficiently constant without compromising the specification parameters of the CIXS. We have chosen a minimum 3 mm combined thickness of the six beryllium windows needed in a Dewar-type enclosure and showed that a single window of 0.5 mm thickness satisfies tritium containment requirements. For measuring the temperature in cooler ITER plasmas, we have chosen to use the K-shell lines of Fe24+. Iron is the preferred choice because its radiation can be analyzed with the identical CIXS settings used for analyzing the tungsten radiation, i.e., essentially no adjustments besides a simple crystal rotation need to be made. We have, however, included an xy{theta}-drive motor arrangement in our design for fine adjustments and full rotation of the crystal mounts.

Beiersdorfer, P; Wen, J; Dunn, J; Morris, K

2011-01-02

181

Optical designs of reflection and refraction collection optics for a JT-60SA core Thomson scattering system  

SciTech Connect

Collection optics for core measurements in a JT-60SA Thomson scattering system were designed. The collection optics will be installed in a limited space and have a wide field of view and wide wavelength range. Two types of the optics are therefore suggested: refraction and reflection types. The reflection system, with a large primary mirror, avoids large chromatic aberrations. Because the size limit of the primary mirror and vignetting due to the secondary mirror affect the total collection throughput, conditions that provide the high throughput are found through an optimization. A refraction system with four lenses forming an Ernostar system is also employed. The use of high-refractive-index glass materials enhances the freedom of the lens curvatures, resulting in suppression of the spherical and coma aberration. Moreover, sufficient throughput can be achieved, even with smaller lenses than that of a previous design given in [H. Tojo, T. Hatae, T. Sakuma, T. Hamano, K. Itami, Y. Aida, S. Suitoh, and D. Fujie, Rev. Sci. Instrum. 81, 10D539 (2010)]. The optical resolutions of the reflection and refraction systems are both sufficient for understanding the spatial structures in plasma. In particular, the spot sizes at the image of the optics are evaluated as ?0.3?mm and ?0.4?mm, respectively. The throughput for the two systems, including the pupil size and transmissivity, are also compared. The results show that good measurement accuracy (<10%) even at high electron temperatures (<30?keV) can be expected in the refraction system.

Tojo, H.; Hatae, T.; Hamano, T.; Sakuma, T.; Itami, K. [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka 311-0193 (Japan)] [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka 311-0193 (Japan)

2013-09-15

182

Management of grossly destroyed endodontically treated teeth with lock and key custom modified cast post and core design: A case series  

PubMed Central

The purpose of this paper is to demonstrate a more retentive custom modified lock and key design of metal cast post and core for the restoration of grossly destroyed endodontically treated molar tooth. The lock and key metal cast post consists of two parts, one in the distal canal (primary post) and the other one in mesio-lingual canal (secondary post). The primary post has a lock design, while the secondary post contains the key design, both of which interlock together. Lock and key cast post, mentioned in this report can be an effective design for the management of grossly destroyed molar teeth. PMID:25684919

Deenadayalan, E.; Kumar, Ashok; Tewari, Rajendra Kumar; Mishra, Surendra Kumar; Alam, Sharique

2015-01-01

183

Analysis of overall temperature coefficient of reactivity of the VHTRC-1 core with a nuclear design code system for the high-temperature engineering test reactor  

Microsoft Academic Search

In this paper the accuracy of the nuclear design code system for the High-Temperature Engineering Test Reactor (HTTR) is evaluated for the neutronic characteristics that depend on core temperature by analyzing the overall temperature coefficients of reactivity and the effective multiplication factors obtained by an experiment in which the Very High Temperature Reactor Critical Assembly (VHTRC) is heated from ambient

K. Yamashita; I. Murata; R. Shindo

1992-01-01

184

Quiet Clean Short-haul Experimental Engine (QCSEE) Under-The-Wing (UTW) boiler plate nacelle and core exhaust nozzle design report  

NASA Technical Reports Server (NTRS)

The mechanical design of the boiler plate nacelle and core exhaust nozzle for the QCSEE under the wing engine is presented. The nacelle, which features interchangeable hard-wall and acoustic panels, is to be utilized in the initial engine testing to establish acoustic requirements for the subsequent composite nacelle as well as in the QCSEE over the wing engine configuration.

1976-01-01

185

Design and development of a run-time monitor for multi-core architectures in cloud computing.  

PubMed

Cloud computing is a new information technology trend that moves computing and data away from desktops and portable PCs into large data centers. The basic principle of cloud computing is to deliver applications as services over the Internet as well as infrastructure. A cloud is a type of parallel and distributed system consisting of a collection of inter-connected and virtualized computers that are dynamically provisioned and presented as one or more unified computing resources. The large-scale distributed applications on a cloud require adaptive service-based software, which has the capability of monitoring system status changes, analyzing the monitored information, and adapting its service configuration while considering tradeoffs among multiple QoS features simultaneously. In this paper, we design and develop a Run-Time Monitor (RTM) which is a system software to monitor the application behavior at run-time, analyze the collected information, and optimize cloud computing resources for multi-core architectures. RTM monitors application software through library instrumentation as well as underlying hardware through a performance counter optimizing its computing configuration based on the analyzed data. PMID:22163811

Kang, Mikyung; Kang, Dong-In; Crago, Stephen P; Park, Gyung-Leen; Lee, Junghoon

2011-01-01

186

From rational design of organometallic precursors to optimized synthesis of core/shell Ge/GeO2 nanoparticles.  

PubMed

The synthesis of germanium nanoparticles has been carried out, thanks to the design of novel aminoiminate germanium(ii) precursors: (ATI)GeZ (with Z = OMe, NPh2, and ATI = N,N'-diisopropyl-aminotroponiminate) and (Am)2Ge (Am = N,N'-bis(trimethylsilyl)phenyl amidinate). These complexes were fully characterized by spectroscopic techniques as well as single crystal X-ray diffraction. The thermolysis of both complexes yielded NPs which display similar features that are a Ge/GeO2 core/shell structure with a mean diameter close to 5 nm with a narrow size distribution (<15%). Whereas the high temperatures (>300 °C) classically reported in the literature for the preparation of germanium-based NPs were necessary for thermolysis of the complexes (ATI)GeZ, the use of amidinate-based precursors allows the preparation at an unprecedented low temperature (160 °C) for the thermolytic route. As suggested by a mechanistic study, the lower reactivity of (ATI)GeZ (for which the concomitant use of high temperature and acidic reagent is required) was explained in terms of lower ring strain compared to the case of (Am)2Ge. PMID:25790067

Matioszek, D; Ojo, W-S; Cornejo, A; Katir, N; El Ezzi, M; Le Troedec, M; Martinez, H; Gornitzka, H; Castel, A; Nayral, C; Delpech, F

2015-04-01

187

TRAC analyses for CCTF and SCTF tests and UPTF design/operation. [Cylindrical Core Test Facility; Slab Core Test Facility; Upper Plenum Test Facility  

SciTech Connect

The analytical support in 1985 for Cylindrical Core Test Facility (CCTF), Slab Core Test Facility (SCTF), and Upper Plenum Test Facility (UPTF) tests involves the posttest analysis of 16 tests that have already been run in the CCTF and the SCTF and the pretest analysis of 3 tests to be performed in the UPTF. Posttest analysis is used to provide insight into the detailed thermal-hydraulic phenomena occurring during the refill and reflood tests performed in CCTF and SCTF. Pretest analysis is used to ensure that the test facility is operated in a manner consistent with the expected behavior of an operating full-scale plant during an accident. To obtain expected behavior of a plant during an accident, two plant loss-of-coolant-accident (LOCA) calculations were performed: a 200% cold-leg-break LOCA calculation for a 2772 MW(t) Babcock and Wilcox plant and a 200% cold-leg-break LOCA calculation for a 3315 MW(t) Westinghouse plant. Detailed results are presented for several CCTF UPI tests and the Westinghouse plant analysis.

Spore, J.W.; Cappiello, M.W.; Dotson, P.J.; Gilbert, J.S; Martinez, V.; Stumpf, H.J.

1985-01-01

188

Coring Sample Acquisition Tool  

NASA Technical Reports Server (NTRS)

A sample acquisition tool (SAT) has been developed that can be used autonomously to sample drill and capture rock cores. The tool is designed to accommodate core transfer using a sample tube to the IMSAH (integrated Mars sample acquisition and handling) SHEC (sample handling, encapsulation, and containerization) without ever touching the pristine core sample in the transfer process.

Haddad, Nicolas E.; Murray, Saben D.; Walkemeyer, Phillip E.; Badescu, Mircea; Sherrit, Stewart; Bao, Xiaoqi; Kriechbaum, Kristopher L.; Richardson, Megan; Klein, Kerry J.

2012-01-01

189

Building core capacities at the designated points of entry according to the International Health Regulations 2005: a review of the progress and prospects in Taiwan  

PubMed Central

Background As designated points of entry (PoEs) play a critical role in preventing the transmission of international public health risks, huge efforts have been invested in Taiwan to improve the core capacities specified in the International Health Regulations 2005 (IHR 2005). This article reviews how Taiwan strengthened the core capacities at the Taoyuan International Airport (TIA) and the Port of Kaohsiung (PoK) by applying a new, practicable model. Design An IHR PoE program was initiated for implementing the IHR core capacities at designated PoEs. The main methods of this program were 1) identifying the designated PoEs according to the pre-determined criteria, 2) identifying the competent authority for each health measure, 3) building a close collaborative relationship between stakeholders from the central and PoE level, 4) designing three stages of systematic assessment using the assessment tool published by the World Health Organization (WHO), and 5) undertaking action plans targeting the gaps identified by the assessments. Results Results of the self-assessment, preliminary external assessment, and follow-up external assessment revealed a continuous progressive trend at the TIA (86, 91, and 100%, respectively), and at the PoK (77, 97, and 99.9%, respectively). The results of the follow-up external assessment indicated that both these designated PoEs already conformed to the IHR requirements. These achievements were highly associated with strong collaboration, continuous empowerment, efficient resource integration, and sustained commitments. Conclusions Considering that many countries had requested for an extension on the deadline to fulfill the IHR 2005 core capacity requirements, Taiwan's experiences can be a source of learning for countries striving to fully implement these requirements. Further, in order to broaden the scope of public health protection into promoting global security, Taiwan will keep its commitments on multisectoral cooperation, human resource capacity building, and maintaining routine and emergency capacities. PMID:25037903

Chiu, Hsiao-Hsuan; Hsieh, Jui-Wei; Wu, Yi-Chun; Chou, Jih-Haw; Chang, Feng-Yee

2014-01-01

190

Core sample extractor  

NASA Technical Reports Server (NTRS)

The problem of retrieving and storing core samples from a hole drilled on the lunar surface is addressed. The total depth of the hole in question is 50 meters with a maximum diameter of 100 millimeters. The core sample itself has a diameter of 60 millimeters and will be two meters in length. It is therefore necessary to retrieve and store 25 core samples per hole. The design utilizes a control system that will stop the mechanism at a certain depth, a cam-linkage system that will fracture the core, and a storage system that will save and catalogue the cores to be extracted. The Rod Changer and Storage Design Group will provide the necessary tooling to get into the hole as well as to the core. The mechanical design for the cam-linkage system as well as the conceptual design of the storage device are described.

Akins, James; Cobb, Billy; Hart, Steve; Leaptrotte, Jeff; Milhollin, James; Pernik, Mark

1989-01-01

191

Design of refractive index sensors based on the wavelength-selective resonant coupling phenomenon in dual-core photonic crystal fibers  

NASA Astrophysics Data System (ADS)

Design strategies for high-sensitivity refractive index sensors based on the principle of wavelength-selective resonant coupling in dual-core photonic crystal fibers are presented. Phase matching at a single wavelength can be achieved between an analyte-filled microstructured core and a small core with a down-doped rod or one small air hole in the center, thus enabling selectively directional resonant-coupling between the two cores. The transmission spectra of the output light presents a notch at the index-matched wavelength, yielding a resonant wavelength depending on the refractive index of the analyte. Numerical simulations demonstrate that both of the two proposed sensors can be used for highly sensitive detection of low-index analyte. In particular, the configuration realized by introducing the fiber with a small air hole in one core can be used to the detection of the analyte index around 1.33 and the sensitivity reach to 1.2×104 nm per refractive index unit (RIU). In addition, the detection limit is as low as 2.5×10-7 RIU at na=1.33.

Sun, Bing; Chen, Ming-Yang; Zhang, Yong-Kang; Yang, Ji-chang

2012-03-01

192

Use of data obtained from core tests in the design and operation of spent brine injection wells in geopressured or geothermal systems  

SciTech Connect

The effects of formation characteristics on injection well performance are reviewed. Use of data acquired from cores taken from injection horizons to predict injectivity is described. And methods for utilizing data from bench scale testing of brine and core samples to optimize injection well design are presented. Currently available methods and equipment provide data which enable the optimum design of injection wells through analysis of cores taken from injection zones. These methods also provide a means of identifying and correcting well injection problems. Methods described in this report are: bulk density measurement; porosity measurement; pore size distribution analysis; permeability measurement; formation grain size distribution analysis; core description (lithology) and composition; amount, type and distribution of clays and shales; connate water analysis; consolidatability of friable reservoir rocks; grain and pore characterization by scanning electron microscopy; grain and pore characterization by thin section analysis; permeability damage and enhancement tests; distribution of water-borne particles in porous media; and reservoir matrix acidizing effectiveness. The precise methods of obtaining this information are described, and their use in the engineering of injection wells is illustrated by examples, where applicable. (MHR)

Jorda, R.M.

1980-03-01

193

The influence of the root cross-section on the stress distribution in teeth restored with a positive-locking post and core design: a finite element study.  

PubMed

Human teeth with substantial coronal defects are subject to reconstruction by means of post and core restorations. Typically, such a restoration comprises a slightly cylindrical post onto which an abutment of varying shape, depending on the designated restoration, is attached. As clinical results are not satisfactory to date, we proposed a new proprietary post and core design which makes use of positive locking. As this prefabricated system is not customised to an individual root's cross-sectional geometry (usually oval), a varying amount of radicular dentin is left in periphery of the core's outer edge. The aim of this study was to assess the implications of this fact, i.e., whether the root has to endure higher overall stress levels which ultimately may lead to failure of one of the components involved. A series of finite element simulations were performed to evaluate stress and strain on the system, in which the proposed post and core was embedded into a virtual dentin cylinder of different diameters, ranging from flush mounting of the restoration to a dentin excess of 4 mm, and subsequently loaded with forces with two angles of attack (90 degrees and 130 degrees ). The results show that flush mounting yields an agreeable stress and strain distribution within the radicular dentin, but overall stress levels drop significantly with an excess of 0.5 mm of surrounding dentin. More than 1 mm excess was not found to have profound positive effects. PMID:18803526

Schilling, Kai-Uwe; Rottner, Kurt; Boldt, Julian; Proff, Peter; Gredes, Tomasz; Richter, Ernst-Jürgen; Reicheneder, Claudia

2008-10-01

194

The application of surface demoldability and moldability to side-core design in die and mold CAD  

Microsoft Academic Search

In casting, molding and forming processes, the surface geometries of the fabricated products are formed\\/molded by different functional components of tooling. In plastic injection molding, they are molded by core, cavity or side-cores. In die and mold CAD, how to identify the product surfaces formed\\/molded by the corresponding tool components for a given product CAD model is critical, as it

M. W. Fu

2008-01-01

195

High Temperature Reactor (HTR) Deep Burn Core and Fuel Analysis: Design Selection for the Prismatic Block Reactor With Results from FY-2011 Activities  

SciTech Connect

The Deep Burn (DB) Project is a U.S. Department of Energy sponsored feasibility study of Transuranic Management using high burnup fuel in the high temperature helium cooled reactor (HTR). The DB Project consists of seven tasks: project management, core and fuel analysis, spent fuel management, fuel cycle integration, TRU fuel modeling, TRU fuel qualification, and HTR fuel recycle. In the Phase II of the Project, we conducted nuclear analysis of TRU destruction/utilization in the HTR prismatic block design (Task 2.1), deep burn fuel/TRISO microanalysis (Task 2.3), and synergy with fast reactors (Task 4.2). The Task 2.1 covers the core physics design, thermo-hydraulic CFD analysis, and the thermofluid and safety analysis (low pressure conduction cooling, LPCC) of the HTR prismatic block design. The Task 2.3 covers the analysis of the structural behavior of TRISO fuel containing TRU at very high burnup level, i.e. exceeding 50% of FIMA. The Task 4.2 includes the self-cleaning HTR based on recycle of HTR-generated TRU in the same HTR. Chapter IV contains the design and analysis results of the 600MWth DB-HTR core physics with the cycle length, the average discharged burnup, heavy metal and plutonium consumptions, radial and axial power distributions, temperature reactivity coefficients. Also, it contains the analysis results of the 450MWth DB-HTR core physics and the analysis of the decay heat of a TRU loaded DB-HTR core. The evaluation of the hot spot fuel temperature of the fuel block in the DB-HTR (Deep-Burn High Temperature Reactor) core under full operating power conditions are described in Chapter V. The investigated designs are the 600MWth and 460MWth DB-HTRs. In Chapter VI, the thermo-fluid and safety of the 600MWth DB-HTRs has been analyzed to investigate a thermal-fluid design performance at the steady state and a passive safety performance during an LPCC event. Chapter VII describes the analysis results of the TRISO fuel microanalysis of the 600MWth and 450MWth DB-HTRs. The TRISO fuel microanalysis covers the gas pressure buildup in a coated fuel particle including helium production, the thermo-mechanical behavior of a CFP, the failure probabilities of CFPs, the temperature distribution in a CPF, and the fission product (FP) transport in a CFP and a graphite. In Chapter VIII, it contains the core design and analysis of sodium cooled fast reactor (SFR) with deep burn HTR reactor. It considers a synergistic combination of the DB-MHR and an SFR burner for a safe and efficient transmutation of the TRUs from LWRs. Chapter IX describes the design and analysis results of the self-cleaning (or self-recycling) HTR core. The analysis is considered zero and 5-year cooling time of the spent LWR fuels.

Michael A. Pope

2011-10-01

196

Design and evaluation of hydrophobic coated buoyant core as floating drug delivery system for sustained release of cisapride  

PubMed Central

An inert hydrophobic buoyant coated–core was developed as floating drug delivery system (FDDS) for sustained release of cisapride using direct compression technology. Core contained low density, porous ethyl cellulose, which was coated with an impermeable, insoluble hydrophobic coating polymer such as rosin. It was further seal coated with low viscosity hydroxypropyl methyl cellulose (HPMC E15) to minimize moisture permeation and better adhesion with an outer drug layer. It was found that stable buoyant core was sufficient to float the tablet more than 8 h without the aid of sodium bicarbonate and citric acid. Sustained release of cisapride was achieved with HPMC K4M in the outer drug layer. The floating lag time required for these novel FDDS was found to be zero, however it is likely that the porosity or density of the core is critical for floatability of these tablets. The in vitro release pattern of these tablets in simulated gastric fluid showed the constant and controlled release for prolonged time. It can be concluded that the hydrophobic coated buoyant core could be used as FDDS for gastroretentive delivery system of cisapride or other suitable drugs. PMID:24825997

Jacob, Shery; Nair, Anroop B; Patil, Pandurang N

2010-01-01

197

Design of two kinds of dual-core high birefringence and high coupling degree photonic crystal fibers  

NASA Astrophysics Data System (ADS)

We propose two kinds of dual-core high birefringence and high coupling degree photonic crystal fibers (DHBHCD-PCFs) in this paper. The characteristics of birefringence and coupling are studied by multipole method. Numerical results show that the birefringence and the coupling length reach an order of 10 - 2 and 10 - 5 m at 1.55 ?m, respectively. It is found that the birefringence and the coupling intensity increase with the increase of air-filling fraction, which is different from other dual-core fibers. The DHBHCD-PCFs with high degree of polarization-maintaining and high coupling degree are helpful for manufacturing minitype photonic apparatus.

Fu, Bo; Li, Shu-Guang; Yao, Yan-Yan; Zhang, Lei; Zhang, Mei-Yan

2010-10-01

198

Nuclear safety analyses and core design calculations to convert the Texas A & M University Nuclear Science Center reactor to low enrichment uranium fuel. Final report  

SciTech Connect

This project involved performing the nuclear design and safety analyses needed to modify the license issued by the Nuclear Regulatory Commission to allow operation of the Texas A& M University Nuclear Science Center Reactor (NSCR) with a core containing low enrichment uranium (LEU) fuel. The specific type of LEU fuel to be considered was the TRIGA 20-20 fuel produced by General Atomic. Computer codes for the neutronic analyses were provided by Argonne National Laboratory (ANL) and the assistance of William Woodruff of ANL in helping the NSCR staff to learn the proper use of the codes is gratefully acknowledged. The codes applied in the LEU analyses were WIMSd4/m, DIF3D, NCTRIGA and PARET. These codes allowed full three dimensional, temperature and burnup dependent calculations modelling the NSCR core to be performed for the first time. In addition, temperature coefficients of reactivity and pulsing calculations were carried out in-house, whereas in the past this modelling had been performed at General Atomic. In order to benchmark the newly acquired codes, modelling of the current NSCR core with highly enriched uranium fuel was also carried out. Calculated results were compared to both earlier licensing calculations and experimental data and the new methods were found to achieve excellent agreement with both. Therefore, even if an LEU core is never loaded at the NSCR, this project has resulted in a significant improvement in the nuclear safety analysis capabilities established and maintained at the NSCR.

Parish, T.A.

1995-03-02

199

Modeling and design of a new core-moderator assembly and neutron beam ports for the Penn State Breazeale Nuclear Reactor (PSBR)  

NASA Astrophysics Data System (ADS)

This study is for modeling and designing a new reactor core-moderator assembly and new neutron beam ports that aimed to expand utilization of a new beam hall of the Penn State Breazeale Reactor (PSBR). The PSBR is a part of the Radiation Science and Engineering Facility (RSEC) and is a TRIGA MARK III type research reactor with a movable core placed in a large pool and is capable to produce 1MW output. This reactor is a pool-type reactor with pulsing capability up to 2000 MW for 10-20 msec. There are seven beam ports currently installed to the reactor. The PSBR's existing core design limits the experimental capability of the facility, as only two of the seven available neutron beam ports are usable. The finalized design features an optimized result in light of the data obtained from neutronic and thermal-hydraulics analyses as well as geometrical constraints. A new core-moderator assembly was introduced to overcome the limitations of the existing PSBR design, specifically maximizing number of available neutron beam ports and mitigating the hydrogen gamma contamination of the neutron beam channeled in the beam ports. A crescent-shaped moderator is favored in the new PSBR design since it enables simultaneous use of five new neutron beam ports in the facility. Furthermore, the crescent shape sanctions a coupling of the core and moderator, which reduces the hydrogen gamma contamination significantly in the new beam ports. A coupled MURE and MCNP5 code optimization analysis was performed to calculate the optimum design parameters for the new PSBR. Thermal-hydraulics analysis of the new design was achieved using ANSYS Fluent CFD code. In the current form, the PSBR is cooled by natural convection of the pool water. The driving force for the natural circulation of the fluid is the heat generation within the fuel rods. The convective heat data was generated at the reactor's different operating powers by using TRIGSIMS, the fuel management code of the PSBR core. In the CFD modeling, the amount of heat generated by the fuel is assumed to be transferred totally into the coolant. Therefore, the surface heat flux is applied to the fuel cladding outer surface by considering the depleted fuel composition of each individual fuel rod under a reference core loading condition defined as; 53H at 1MW full power. In order to model the entire PSBR reactor, fine mesh discretization was achieved with 22 millions structured and unstructured computational meshes. The conductive heat transfer inside the fuel rods was ignored in order to decrease the computational mesh requirement. Since the PSBR core operates in the subcooled nucleate boiling region, the CFD simulation of new PSBR design was completed utilizing an Eulerian-Eulerian multiphase flow formulation and RPI wall boiling model. The simulation results showed that the new moderator tank geometry results in secondary flow entering into the core due to decrease in the cross-flow area. Notably, the radial flow improves the local heat transfer conditions by providing radial-mixing in the core. Bubble nucleation occurs on the heated fuel rods but bubbles are collapsing in the subcooled fluid. Furthermore, the bulk fluid properties are not affected by the bubble formation. Yet, subcooled boiling enhances the heat transfer on the fuel rods. Five neutron beam ports are designed for the new reactor. The geometrical configuration, filter and collimator system designs of each neutron beam ports are selected based on the requirements of the experimental facilities. A cold neutron beam port which utilizes cold neutrons from three curved guide tubes is considered. Therefore, there will be seven neutron beams available in the new facility. The neutronic analyses of the new beam port designs were achieved by using MCNP5 code and Burned Coupled Simulation Tool for the PSBR. The MCNP simulation results showed that thermal neutron flux was increased by a factor of minimum 1.23 times and maximum 2.68 times in the new beam port compared to the existing BP4 design. Besides total gamma dose was decreased by a factor

Ucar, Dundar

200

The Design and Implementation of the Parallel Out-of-core ScaLAPACK LU, QR and Cholesky  

E-print Network

routines, as well as performance and scalability results on a Beowulf linux cluster. This work typically takes less than 30minutes. On a Beowulf network of workstations (NOW) with 50 processors, it may run time becomes prohibitively large. Therefore, it is natural to develop parallel out-of-core solvers

Dongarra, Jack

201

Design of 154 kV class 100 MVA 3 phase HTS transformer on a common magnetic core  

Microsoft Academic Search

We have proposed a high temperature superconducting (HTS) transformer which can substitute for a conventional oil transformer for power distribution in Korea. The conventional transformer is composed of three identical single phase transformers because of the limitations on volume and weight. Now the Korean power company has started to consider the possibility of a transformer on a common magnetic core

J. Choi; S. Lee; W. Kim; S. Kim; J. Han; H. Lee; K. Choi

2007-01-01

202

US higher education environmental program managers' perspectives on curriculum design and core competencies : Implications for sustainability as a guiding framework  

Microsoft Academic Search

Purpose – This study is the first of a five-phase research project sponsored by the Council of Environmental Deans and Directors (CEDD), an organization of environmental program managers operating under the umbrella of the National Council for Science and the Environment. The purpose of the project is to determine if a consensus on core competencies for environmental program graduates is

Shirley Vincent; Will Focht

2009-01-01

203

Comparison of MARC Content Designation Utilization in OCLC WorldCat Records with National, Core, and Minimal Level Record Standards  

Microsoft Academic Search

Commonly used fields and subfields in 56 million Online Computer Library Center (OCLC) WorldCat bibliographic records are identified based on the analysis of format-specific record sets and the calculation of utilization thresholds, with the purpose of comparing these elements with existing recommendations by Library of Congress (LC) agencies for national, core, and minimal level records. The background and purposes of

Amy P. Eklund; Shawne D. Miksa; William E. Moen; Gregory Snyder; Serhiy Polyakov

2009-01-01

204

US Higher Education Environmental Program Managers' Perspectives on Curriculum Design and Core Competencies: Implications for Sustainability as a Guiding Framework  

ERIC Educational Resources Information Center

Purpose: This study is the first of a five-phase research project sponsored by the Council of Environmental Deans and Directors (CEDD), an organization of environmental program managers operating under the umbrella of the National Council for Science and the Environment. The purpose of the project is to determine if a consensus on core

Vincent, Shirley; Focht, Will

2009-01-01

205

Rational design of high-surface-area carbon nanotube/microporous carbon core-shell nanocomposites for supercapacitor electrodes.  

PubMed

All-carbon-based carbon nanotube (CNT)/microporous carbon core-shell nanocomposites, in which a CNT as the core and high-surface-area microporous carbon as the shell, have been prepared by in situ resorcinol-formaldehyde resin coating of CNTs, followed by carbonization and controlled KOH activation. The obtained nanocomposites have very high Brunauer-Emmett-Teller surface areas (up to 1700 m(2)/g), narrow pore size distribution (<2 nm), and 1D tubular structure within a 3D entangled network. The thickness of the microporous carbon shell can be easily tuned from 20 to 215 nm by changing the carbon precursor/CNT mass ratio. In such a unique core-shell structure, the CNT core could mitigate the key issue related to the low electronic conductivity of microporous carbons. On the other hand, the 1D tubular structure with a short pore-pathway micropore as well as a 3D entangled network could increase the utilization degree of the overall porosity and improve the electrode kinetics. Thus, these CNT/microporous carbon core-shell nanocomposites exhibit a great potential as an electrode material for supercapacitors, which could deliver high specific capacitance of 237 F/g, excellent rate performance with 75% maintenance from 0.1 to 50 A/g, and high cyclability in H2SO4 electrolyte. Moreover, the precisely controlled microporous carbon shells may allow them to serve as excellent model systems for microporous carbons, in general, to illustrate the role of the pore length on the diffusion and kinetics inside the micropores. PMID:25654564

Yao, Yuanyuan; Ma, Cheng; Wang, Jitong; Qiao, Wenming; Ling, Licheng; Long, Donghui

2015-03-01

206

HYDRATE CORE DRILLING TESTS  

SciTech Connect

The ''Methane Hydrate Production from Alaskan Permafrost'' project is a three-year endeavor being conducted by Maurer Technology Inc. (MTI), Noble, and Anadarko Petroleum, in partnership with the U.S. DOE National Energy Technology Laboratory (NETL). The project's goal is to build on previous and ongoing R&D in the area of onshore hydrate deposition. The project team plans to design and implement a program to safely and economically drill, core and produce gas from arctic hydrates. The current work scope includes drilling and coring one well on Anadarko leases in FY 2003 during the winter drilling season. A specially built on-site core analysis laboratory will be used to determine some of the physical characteristics of the hydrates and surrounding rock. Prior to going to the field, the project team designed and conducted a controlled series of coring tests for simulating coring of hydrate formations. A variety of equipment and procedures were tested and modified to develop a practical solution for this special application. This Topical Report summarizes these coring tests. A special facility was designed and installed at MTI's Drilling Research Center (DRC) in Houston and used to conduct coring tests. Equipment and procedures were tested by cutting cores from frozen mixtures of sand and water supported by casing and designed to simulate hydrate formations. Tests were conducted with chilled drilling fluids. Tests showed that frozen core can be washed out and reduced in size by the action of the drilling fluid. Washing of the core by the drilling fluid caused a reduction in core diameter, making core recovery very difficult (if not impossible). One successful solution was to drill the last 6 inches of core dry (without fluid circulation). These tests demonstrated that it will be difficult to capture core when drilling in permafrost or hydrates without implementing certain safeguards. Among the coring tests was a simulated hydrate formation comprised of coarse, large-grain sand in ice. Results with this core showed that the viscosity of the drilling fluid must also be carefully controlled. When coarse sand was being cored, the core barrel became stuck because the drilling fluid was not viscous enough to completely remove the large grains of sand. These tests were very valuable to the project by showing the difficulties in coring permafrost or hydrates in a laboratory environment (as opposed to a field environment where drilling costs are much higher and the potential loss of equipment greater). Among the conclusions reached from these simulated hydrate coring tests are the following: Frozen hydrate core samples can be recovered successfully; A spring-finger core catcher works best for catching hydrate cores; Drilling fluid can erode the core and reduces its diameter, making it more difficult to capture the core; Mud must be designed with proper viscosity to lift larger cuttings; and The bottom 6 inches of core may need to be drilled dry to capture the core successfully.

John H. Cohen; Thomas E. Williams; Ali G. Kadaster; Bill V. Liddell

2002-11-01

207

Lead users’ ideas on core features to support physical activity in rheumatoid arthritis: a first step in the development of an internet service using participatory design  

PubMed Central

Background Despite the growing evidence of the benefits of physical activity (PA) in individuals with rheumatoid arthritis (RA), the majority is not physically active enough. An innovative strategy is to engage lead users in the development of PA interventions provided over the internet. The aim was to explore lead users’ ideas and prioritization of core features in a future internet service targeting adoption and maintenance of healthy PA in people with RA. Methods Six focus group interviews were performed with a purposively selected sample of 26 individuals with RA. Data were analyzed with qualitative content analysis and quantification of participants’ prioritization of most important content. Results Six categories were identified as core features for a future internet service: up-to-date and evidence-based information and instructions, self-regulation tools, social interaction, personalized set-up, attractive design and content, and access to the internet service. The categories represented four themes, or core aspects, important to consider in the design of the future service: (1) content, (2) customized options, (3) user interface and (4) access and implementation. Conclusions This is, to the best of our knowledge, the first study involving people with RA in the development of an internet service to support the adoption and maintenance of PA. Participants helped identifying core features and aspects important to consider and further explore during the next phase of development. We hypothesize that involvement of lead users will make transfer from theory to service more adequate and user-friendly and therefore will be an effective mean to facilitate PA behavior change. PMID:24655757

2014-01-01

208

Introduction to Hardware-dependent Software Design Hardware-dependent Software for Multi-and Many-Core Embedded Systems  

E-print Network

significantly gained relevance in embed- ded systems and Systems-on-Chip (SoCs) design, mainly due to its. The hardware design community is well-aware of the pro- ductivity gap in hardware design. For many years now functions of 10x every 10 years [5]. Considering that additional software productiv- ity gap, the situation

Doemer, Rainer

209

Design and analysis of a low-loss terahertz directional coupler based on three-core photonic crystal fibre configuration  

NASA Astrophysics Data System (ADS)

A novel kind of terahertz directional optical fibre coupler is proposed. The coupling characteristics and operation bandwidth of the three-core photonic crystal fibre coupler are investigated. Numerical results show that it is possible to achieve a broadband terahertz fibre coupler with a small fibre length of a few centimetres. In addition, a modified configuration, which can achieve a wider bandwidth and lower absorption loss, is proposed.

Chen, Ming-Yang; Fu, Xiao-Xia; Zhang, Yong-Kang

2011-10-01

210

Neutronics methods, models, and applications at the Idaho National Engineering Laboratory for the advanced neutron source reactor three-element core design  

SciTech Connect

A summary of the methods and models used to perform neutronics analyses on the Advanced Neutron Source reactor three-element core design is presented. The applications of the neutral particle Monte Carlo code MCNP are detailed, as well as the expansion of the static role of MCNP to analysis of fuel cycle depletion calculations. Results to date of these applications are presented also. A summary of the calculations not yet performed is also given to provide a {open_quotes}to-do{close_quotes} list if the project is resurrected.

Wemple, C.A.; Schnitzler, B.G.; Ryskamp, J.M. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

1995-08-01

211

Proposed Design and Operation of a Heat Pipe Reactor using the Sandia National Laboratories Annular Core Test Facility and Existing UZrH Fuel Pins  

SciTech Connect

Heat Pipe Reactors (HPR) for space power conversion systems offer a number of advantages not easily provided by other systems. They require no pumping, their design easily deals with freezing and thawing of the liquid metal, and they can provide substantial levels of redundancy. Nevertheless, no reactor has ever been operated and cooled with heat pipes, and the startup and other operational characteristics of these systems remain largely unknown. Signification deviations from normal reactor heat removal mechanisms exist, because the heat pipes have fundamental heat removal limits due to sonic flow issues at low temperatures. This paper proposes an early prototypic test of a Heat Pipe Reactor (using existing 20% enriched nuclear fuel pins) to determine the operational characteristics of the HPR. The proposed design is similar in design to the HOMER and SAFE-300 HPR designs (Elliot, Lipinski, and Poston, 2003; Houts, et. al, 2003). However, this reactor uses existing UZrH fuel pins that are coupled to potassium heat pipes modules. The prototype reactor would be located in the Sandia Annular Core Research Reactor Facility where the fuel pins currently reside. The proposed reactor would use the heat pipes to transport the heat from the UZrH fuel pins to a water pool above the core, and the heat transport to the water pool would be controlled by adjusting the pressure and gas type within a small annulus around each heat pipe. The reactor would operate as a self-critical assembly at power levels up to 200 kWth. Because the nuclear heated HPR test uses existing fuel and because it would be performed in an existing facility with the appropriate safety authorization basis, the test could be performed rapidly and inexpensively. This approach makes it possible to validate the operation of a HPR and also measure the feedback mechanisms for a typical HPR design. A test of this nature would be the world's first operating Heat Pipe Reactor. This reactor is therefore called 'HPR-1'.

Wright, Steven A.; Lipinski, Ronald J.; Pandya, Tara; Peters, Curtis [Sandia National Laboratories, Org 6872 MS-1146, PO Box 5800 Albuquerque, New Mexico 87185 (United States)

2005-02-06

212

Core-shell designs of photoluminescent nanodiamonds with porous silica coatings for bioimaging and drug delivery II: application  

NASA Astrophysics Data System (ADS)

Recent advances within materials science and its interdisciplinary applications in biomedicine have emphasized the potential of using a single multifunctional composite material for concurrent drug delivery and biomedical imaging. Here we present a novel composite material consisting of a photoluminescent nanodiamond (ND) core with a porous silica (SiO2) shell. This novel multifunctional probe serves as an alternative nanomaterial to address the existing problems with delivery and subsequent tracing of the particles. Whereas the unique optical properties of ND allows for long-term live cell imaging and tracking of cellular processes, mesoporous silica nanoparticles (MSNs) have proven to be efficient drug carriers. The advantages of both ND and MSNs were hereby integrated in the new composite material, ND@MSN. The optical properties provided by the ND core rendered the nanocomposite suitable for microscopy imaging in fluorescence and reflectance mode, as well as super-resolution microscopy as a STED label; whereas the porous silica coating provided efficient intracellular delivery capacity, especially in surface-functionalized form. This study serves as a demonstration how this novel nanomaterial can be exploited for both bioimaging and drug delivery for future theranostic applications.Recent advances within materials science and its interdisciplinary applications in biomedicine have emphasized the potential of using a single multifunctional composite material for concurrent drug delivery and biomedical imaging. Here we present a novel composite material consisting of a photoluminescent nanodiamond (ND) core with a porous silica (SiO2) shell. This novel multifunctional probe serves as an alternative nanomaterial to address the existing problems with delivery and subsequent tracing of the particles. Whereas the unique optical properties of ND allows for long-term live cell imaging and tracking of cellular processes, mesoporous silica nanoparticles (MSNs) have proven to be efficient drug carriers. The advantages of both ND and MSNs were hereby integrated in the new composite material, ND@MSN. The optical properties provided by the ND core rendered the nanocomposite suitable for microscopy imaging in fluorescence and reflectance mode, as well as super-resolution microscopy as a STED label; whereas the porous silica coating provided efficient intracellular delivery capacity, especially in surface-functionalized form. This study serves as a demonstration how this novel nanomaterial can be exploited for both bioimaging and drug delivery for future theranostic applications. Electronic supplementary information (ESI) available: DLS and electrokinetic measurements, optical size measurements from PL-signal of individual particles by confocal and STED microscopy, TEM image showing the subcellular localization of pure ND. See DOI: 10.1039/c3nr33926b

Prabhakar, Neeraj; Näreoja, Tuomas; von Haartman, Eva; Karaman, Didem ?en; Jiang, Hua; Koho, Sami; Dolenko, Tatiana A.; Hänninen, Pekka E.; Vlasov, Denis I.; Ralchenko, Victor G.; Hosomi, Satoru; Vlasov, Igor I.; Sahlgren, Cecilia; Rosenholm, Jessica M.

2013-04-01

213

Implementation of a LMS filter on FPGA employing extremeDSP and smart IP-core design  

Microsoft Academic Search

Field Programmable Gate Arrays have become popular platform for digital signal processing, however, the conventional method?» which is essentially writing a source code in a hardware description language to design a product on a FPGA, is time consuming and complicated. This restricts the implementation of complex signal processing algorithm on FPGA. In this paper, two fast design methods of algorithm

Wang Yaqin; Liu Xuebin; Hu Bingliang

2011-01-01

214

Core compressor exit stage study. Volume 5: Design and performance report for the Rotor C/Stator B configuration  

NASA Technical Reports Server (NTRS)

Rear stage blading designs that have lower losses in their endwall boundary layer regions were developed. The design of rotor-C and the performance results for rotor-C running with stator B are described. A low speed research compressor is utilized as the principal investigative tool. Four identical stages of blading are used to obtained data in a true multistage environment.

Wisler, D. C.

1981-01-01

215

Nutrient Composition of the "Core of the Core" Collection  

Technology Transfer Automated Retrieval System (TEKTRAN)

Samples from the Core Collection designated as the Core of the Core Collection were analyzed from the 2005 crop year. Samples were analyzed for individual amino acids, folic acid and total oil content. Oil mechanically expressed from the seed was analyzed for individual tocopherols and fatty acids...

216

Design of a low enrichment, enhanced fast flux core for the Massachusetts Institute of Technology Research Reactor  

E-print Network

Worldwide, there is limited test reactor capacity to perform the required irradiation experiments on advanced fast reactor materials and fuel designs. This is particularly true in the U.S., which no longer has an operating ...

Ellis, Tyler Shawn

2009-01-01

217

Design Study for a Low-Enriched Uranium Core for the High Flux Isotope Reactor, Annual report for FY 2009  

SciTech Connect

This report documents progress made during FY 2009 in studies of converting the High Flux Isotope Reactor (HFIR) from high enriched uranium (HEU) fuel to low enriched uranium (LEU) fuel. Conversion from HEU to LEU will require a change in fuel form from uranium oxide to a uranium-molybdenum alloy. With axial and radial grading of the fuel foil and an increase in reactor power to 100 MW, calculations indicate that the HFIR can be operated with LEU fuel with no degradation in reactor performance from the current level. Results of selected benchmark studies imply that calculations of LEU performance are accurate. Studies are reported of the application of a silicon coating to surrogates for spheres of uranium-molybdenum alloy. A discussion of difficulties with preparing a fuel specification for the uranium-molybdenum alloy is provided. A description of the progress in developing a finite element thermal hydraulics model of the LEU core is provided.

Chandler, David [ORNL; Freels, James D [ORNL; Ilas, Germina [ORNL; Miller, James Henry [ORNL; Primm, Trent [ORNL; Sease, John D [ORNL; Guida, Tracey [University of Pittsburgh; Jolly, Brian C [ORNL

2010-02-01

218

INTRODUCTION TO THE CORE CURRICULUM  

E-print Network

their value is. The development of the Core Curriculum proceeded with the following assumptions in mind: (11 INTRODUCTION TO THE CORE CURRICULUM The purpose of this guide is to inform members of the Freshman class about Harvard's Core Curriculum. It explains the aims and design of the program, offers some

Chou, James

219

An Overview of Demise Calculations, Conceptual Design Studies, and Hydrazine Compatibility Testing for the GPM Core Spacecraft Propellant Tank  

NASA Technical Reports Server (NTRS)

NASA's Global Precipitation Measurement (GPM) mission is an ongoing Goddard Space Flight Center (GSFC) project whose basic objective is to improve global precipitation measurements. It has been decided that the GPM spacecraft is to be a "design for demise" spacecraft. This requirement resulted in the need for a propellant tank that would also demise or ablate to an appropriate degree upon re-entry. This paper will describe GSFC-performed spacecraft and tankage demise analyses, vendor conceptual design studies, and vendor performed hydrazine compatibility and wettability tests performed on 6061 and 2219 aluminum alloys.

Estes, Robert H.; Moore, N. R.

2007-01-01

220

COLLABORATION BY DESIGN: INTEGRATING CORE PEDAGOGICAL CONTENT AND SPECIAL EDUCATION METHODS COURSES IN A PRESERVICE SECONDARY EDUCATION PROGRAM  

Microsoft Academic Search

In this article the authors describe a collaboratively designed secondary teacher education program focused on the preparation of preservice general education teachers to work effectively with children who have diverse learning needs in inclusive classrooms. The focus of the article is on the collaborative development and initial evaluation of the program by secondary teacher education faculty and special education faculty.

Timothy J. Frey; Debra K. Andres; Leah A. McKeeman

2012-01-01

221

Case Studies of Leading Edge Small Urban High Schools. Core Academic Strategic Designs: 2. Noble Street Charter High School  

ERIC Educational Resources Information Center

This report is one of nine detailed case studies of small urban high schools that served as the foundation for the Education Resource Strategies (ERS) report "Strategic Designs: Lessons from Leading Edge Small Urban High Schools." These nine schools were dubbed "Leading Edge Schools" because they stand apart from other high schools across the…

Shields, Regis Anne; Ireland, Nicole; City, Elizabeth; Derderian, Julie; Miles, Karen Hawley

2008-01-01

222

Case Studies of Leading Edge Small Urban High Schools. Core Academic Strategic Designs: 1. Academy of the Pacific Rim  

ERIC Educational Resources Information Center

This report is one of nine detailed case studies of small urban high schools that served as the foundation for the Education Resource Strategies (ERS) report "Strategic Designs: Lessons from Leading Edge Small Urban High Schools." These nine schools were dubbed "Leading Edge Schools" because they stand apart from other high schools across the…

Shields, Regis Anne; Ireland, Nicole; City, Elizabeth; Derderian, Julie; Miles, Karen Hawley

2008-01-01

223

Case Studies of Leading Edge Small Urban High Schools. Core Academic Strategic Designs: 3. University Park Campus School  

ERIC Educational Resources Information Center

This report is one of nine detailed case studies of small urban high schools that served as the foundation for the Education Resource Strategies (ERS) report "Strategic Designs: Lessons from Leading Edge Small Urban High Schools." These nine schools were dubbed "Leading Edge Schools" because they stand apart from other high schools across the…

Shields, Regis Anne; Ireland, Nicole; City, Elizabeth; Derderian, Julie; Miles, Karen Hawley

2008-01-01

224

Collaboration by Design: Integrating Core Pedagogical Content and Special Education Methods Courses in a Preservice Secondary Education Program  

ERIC Educational Resources Information Center

In this article the authors describe a collaboratively designed secondary teacher education program focused on the preparation of preservice general education teachers to work effectively with children who have diverse learning needs in inclusive classrooms. The focus of the article is on the collaborative development and initial evaluation of the…

Frey, Timothy J.; Andres, Debra K.; McKeeman, Leah A.; Lane, Jessica J.

2011-01-01

225

Development of innovative oil-core self-organized nanovesicles prepared with chitosan and lecithin using a 2(3) full-factorial design.  

PubMed

The aim of this study was to develop innovative nanosystems with isopropyl myristate as the oil core of self-assembly nanovesicles constituted of chitosan and lecithin using a 2(3) factorial design. The factors analyzed were chitosan (X1, levels 4 and 8 ?mg/ml), oil (X2, levels 10 and 20? mg/ml) and lecithin (X3, levels 4 and 8?mg/ml). The responses evaluated were diameter, zeta potential, pH, viscosity, and backscattering analysis. The bioavailability was evaluated after oral administration of clozapine free and nanoencapsulated in rats. The diameter ranged from 0.348 to 1.5?µm for F2 (X1, 4; X2, 10; X3, 8?mg/ml) and F7 (X1, 8; X2, 20; X3, 4 ?mg/ml), respectively. Laser diffractometry analysis revealed only one diameter population for all batches. Zeta potential was positive, being influenced by X1 and X2/X3 association. Viscosity values were dependent on the X1 and X2 concentrations used. A structure proposed for the nanosystem consists of chitosan forming the hydrophilic shell layer that protects the core comprised of lecithin and the hydrophobic groups of oil. The AUC0-? was almost 3 times higher with the clozapine nanoencapsuted in relation to free drug. It was developed a new nanosystem which is able of improving the absorption of drugs. PMID:23998248

Haas, Sandra Elisa; de Andrade, Cristiane; Sansone, Pedro Ernesto da Silva; Guterres, Silvia; Dalla Costa, Teresa

2014-11-01

226

Test infrastructure design for core-based system-on-chip under cycle-accurate thermal constraints  

Microsoft Academic Search

We present a thermal-aware test-access mechanism (TAM) design and test scheduling method for system-on-chip (SOC) integrated circuits. The proposed method uses cycle-accurate power profiles for thermal simulation; it also relies on test-set partitioning, test interleaving, and bandwidth matching. We use a computationally tractable thermal-cost model to ensure that temperature constraints are satisfied and the test application time is minimized. Simulation

Thomas Edison Yu; Tomokazu Yoneda; Krishnendu Chakrabarty; Hideo Fujiwara

2009-01-01

227

Pharmacokinetics of core-polymerized, boron-conjugated micelles designed for boron neutron capture therapy for cancer.  

PubMed

Core-polymerized and boron-conjugated micelles (PM micelles) were prepared by free radical copolymerization of a PEG-b-PLA block copolymer bearing an acetal group and a methacryloyl group (acetal-PEG-b-PLA-MA), with 1-(4-vinylbenzyl)-closo-carborane (VB-carborane), and the utility of these micelles as a tumor-targeted boron delivery system was investigated for boron neutron capture therapy (BNCT). Non-polymerized micelles (NPM micelles) that incorporated VB-carborane physically showed significant leakage of VB-carborane (ca. 50%) after 12 h incubation with 10% fetal bovine serum (FBS) at 37 °C. On the other hand, no leakage from the PM micelles was observed even after 48 h of incubation. To clarify the pharmacokinetics of the micelles, (125)I (radioisotope)-labeled PM and NPM micelles were administered to colon-26 tumor-bearing BALB/c mice. The (125)I-labeled PM micelles showed prolonged blood circulation (area under the concentration curve (AUC): 943.4) than the (125)I-labeled NPM micelles (AUC: 495.1), whereas tumor accumulation was similar for both types of micelles (AUC(PM micelle): 249.6, AUC(NPM micelle): 201.1). In contrast, the tumor accumulation of boron species in the PM micelles (AUC: 268.6) was 7-fold higher than the NPM micelles (AUC: 37.1), determined by ICP-AES. Thermal neutron irradiation yielded tumor growth suppression in the tumor-bearing mice treated with the PM micelles without reduction in body weight. On the basis of these data, the PM micelles represent a promising approach to the creation of boron carrier for BNCT. PMID:22326646

Sumitani, Shogo; Oishi, Motoi; Yaguchi, Tatsuya; Murotani, Hiroki; Horiguchi, Yukichi; Suzuki, Minoru; Ono, Koji; Yanagie, Hironobu; Nagasaki, Yukio

2012-05-01

228

Promoting student-led science and technology projects in elementary teacher education: entry into core pedagogical practices through technological design  

Microsoft Academic Search

Future elementary school teachers often lack self-efficacy for teaching science and technology. They are particularly anxious\\u000a about encouraging children to carry-out student-directed, open-ended scientific inquiry and\\/or technological design projects.\\u000a Moreover, because this often also is the case with practising elementary school teachers, it is difficult for student–teachers\\u000a to gain practical experience facilitating student-led project work during practicum sessions. To provide

John Lawrence Bencze

2010-01-01

229

Micro coring apparatus  

NASA Technical Reports Server (NTRS)

A micro-coring apparatus for lunar exploration applications, that is compatible with the other components of the Walking Mobile Platform, was designed. The primary purpose of core sampling is to gain an understanding of the geological composition and properties of the prescribed environment. This procedure has been used extensively for Earth studies and in limited applications during lunar explorations. The corer is described and analyzed for effectiveness.

Collins, David; Brooks, Marshall; Chen, Paul; Dwelle, Paul; Fischer, Ben

1989-01-01

230

Design of single-winding energy-storage reactors for dc-to-dc converters using air-gapped magnetic-core structures  

NASA Technical Reports Server (NTRS)

A procedure is presented for designing air-gapped energy-storage reactors for nine different dc-to-dc converters resulting from combinations of three single-winding power stages for voltage stepup, current stepup and voltage stepup/current stepup and three controllers with control laws that impose constant-frequency, constant transistor on-time and constant transistor off-time operation. The analysis, based on the energy-transfer requirement of the reactor, leads to a simple relationship for the required minimum volume of the air gap. Determination of this minimum air gap volume then permits the selection of either an air gap or a cross-sectional core area. Having picked one parameter, the minimum value of the other immediately leads to selection of the physical magnetic structure. Other analytically derived equations are used to obtain values for the required turns, the inductance, and the maximum rms winding current. The design procedure is applicable to a wide range of magnetic material characteristics and physical configurations for the air-gapped magnetic structure.

Ohri, A. K.; Wilson, T. G.; Owen, H. A., Jr.

1977-01-01

231

Quality by design approach for the separation of naproxcinod and its related substances by fused core particle technology column.  

PubMed

This paper describes the development of a rapid, novel, stability-indicating gradient reversed-phase high-performance liquid chromatographic method and associated system suitability parameters for the analysis of naproxcinod in the presence of its related substances and degradents using a quality-by-design approach. All of the factors that affect the separation of naproxcinod and its impurities and their mutual interactions were investigated and robustness of the method was ensured. The method was developed using an Ascentis Express C8 150 × 4.6 mm, 2.7 µm column with a mobile phase containing a gradient mixture of two solvents. The eluted compounds were monitored at 230 nm, the run time was 20 min within which naproxcinod and its eight impurities were satisfactorily separated. Naproxcinod was subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal and photolytic degradation. Naproxcinod was found to degrade significantly in acidic and basic conditions and to be stable in thermal, photolytic, oxidative and aqueous degradation conditions. The degradation products were satisfactorily resolved from the primary peak and its impurities, proving the stability-indicating power of the method. The developed method was validated as per International Conference on Harmonization guidelines with respect to specificity, linearity, limit of detection, limit of quantification, accuracy, precision and robustness. PMID:23060406

Inugala, Ugandar Reddy; Pothuraju, Nageswara Rao; Vangala, Ranga Reddy

2013-01-01

232

Rational design of ambipolar organic semiconductors: is core planarity central to ambipolarity in thiophene-naphthalene semiconductors?  

PubMed

Herein, we report a new family of naphthaleneamidinemonoimide-fused oligothiophene semiconductors designed for facile charge transport in organic field-effect transistors (OFETs). These molecules have planar skeletons that induce high degrees of crystallinity and hence good charge-transport properties. By modulating the length of the oligothiophene fragment, the majority carrier charge transport can be switched from n-type to ambipolar behavior. The highest FET performance is achieved for solution-processed films of 10-[(2,2'-bithiophen)-5-yl]-2-octylbenzo[lmn]thieno[3',4':4,5]imidazo[2,1-b][3,8]phenanthroline-1,3,6(2H)-trione (NDI-3 Tp), with optimized film mobilities of 2×10(-2) and 0.7×10(-2) cm(2) V(-1) s(-1) for electrons and holes, respectively. Finally, these planar semiconductors are compared with their twisted-skeleton counterparts, which exhibit only n-type mobility, in order to understand the origin of the ambipolarity in this new series of molecular semiconductors. PMID:22161811

Ortiz, Rocío Ponce; Herrera, Helena; Seoane, Carlos; Segura, José L; Facchetti, Antonio; Marks, Tobin J

2012-01-01

233

DUBLIN CORE  

EPA Science Inventory

The Dublin Core is a metadata element set intended to facilitate discovery of electronic resources. It was originally conceived for author-generated descriptions of Web resources, and the Dublin Core has attracted broad ranging international and interdisciplinary support. The cha...

234

Core monitors: monitoring performance in multicore processors  

Microsoft Academic Search

As we reach the limits of single-core computing, we are promised more and more cores in our systems. Modern architectures include many performance counters per core, but few or no inter-core counters. In fact, performance counters were not designed to be exploited by users, as they now are, but simply as aids for hardware debugging and testing during system creation.

Paul E. West; Yuval Peress; Gary S. Tyson; Sally A. Mckee

2009-01-01

235

Wireline sidewall coring  

SciTech Connect

In April 1989, Schlumberger Well Services, under contract to Fenix and Scisson of Nevada, Inc., ran a wireline sidewall coring machine in exploratory hole Ue4t at the Nevada Test Site for the Los Alamos National Laboratory. The sampling project goals were to recover material for geologic characterization and to determine the effectiveness of the tool for sampling various volcanic lithologies. If a wireline tool is found to be effective, fewer expensive continuously-cored holes will be needed. The Schlumberger Sidewall Coredriller has a maximum diameter of 5.25 inches and, with the gamma-ray unit included for stratigraphic correlation, is approximately 40 feet long. It weighs 850 pounds. All the downhole mechanical systems are hydraulic including the anchor shoe, the coring motor, the pressure on the bit and the core extraction system. Sonde functions are monitored and controlled at the surface. The tool is designed to run in fluid with the waterways in the diamond but creating circulation to keep the bit face clean. Up to 20 cores, measuring 0.91 inches in diameter by 2 inches long, can be recovered with each each. These cores are separated in the split-sleeve catcher tube by discs automatically inserted following each coring. 1 ref., 4 figs., 1 tab.

Hawkins, W.L.; Mathews, M.A. (Los Alamos National Lab., NM (USA)); Thompson, P.H. (Fenix and Scisson, Inc., Mercury, NV (USA)); Jenkins, K. (Schlumberger Well Services, Casper, WY (USA))

1989-01-01

236

Starless Cores  

E-print Network

Dense low mass cores in nearby clouds like Taurus and Auriga are some of the simplest sites currently forming stars like our Sun. Because of their simplicity and proximity, dense cores offer the clearest view of the different phases of star formation, in particular the conditions prior to the onset of gravitational collapse. Thanks to the combined analysis of the emission from molecular lines and the emission/absorption from dust grains, the last several years have seen a very rapid progress in our understanding of the structure and chemical composition of starless cores. Previous contradictions between molecular tracers are now understood to arise from core chemical inhomogeneities, which are caused by the selective freeze out of molecules onto cold dust grains. The analysis of the dust emission and absorption, in addition, has allowed us to derive accurate density profiles, and has made finally possible to carry out self consistent modeling of the internal structure of starless cores. In this paper I briefly review the evolution of core studies previous to the current golden age, and show how multi-tracer emission can now be modeled in a systematic manner. Finally I show how we can start to reconstruct the early history of core formation taking advantage of the chemical changes in the gas.

Mario Tafalla

2005-04-23

237

24. A CORE WORKER DISPLAYS THE CORE BOX AND CORES ...  

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

24. A CORE WORKER DISPLAYS THE CORE BOX AND CORES FOR A BRASS GATE VALVE BODY MADE ON A CORE BOX, CA. 1950. - Stockham Pipe & Fittings Company, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

238

Test-wrapper designs for the detection of signal-integrity faults on core-external interconnects of SoCs  

Microsoft Academic Search

As feature sizes continue to shrink for newer process technologies, signal integrity (SI) is emerging as a major concern for core-based system-on-a-chip (SoC) integrated circuits. To effectively test SI faults on core-external interconnects, core test wrappers need to be able to generate appropriate transitions at a wrapper output cell (WOC) on the driving side and detect the signal integrity loss

Qiang Xu; Yubin Zhang; Krishnendu Chakrabarty

2007-01-01

239

Design of functionalized lipids and evidence for their binding to photosystem II core complex by oxygen evolution measurements, atomic force microscopy, and scanning near-field optical microscopy.  

PubMed Central

Photosystem II core complex (PSII CC) absorbs light energy and triggers a series of electron transfer reactions by oxidizing water while producing molecular oxygen. Synthetic lipids with different alkyl chains and spacer lengths bearing functionalized headgroups were specifically designed to bind the Q(B) site and to anchor this large photosynthetic complex (240 kDa) in order to attempt two-dimensional crystallization. Among the series of different compounds that have been tested, oxygen evolution measurements have shown that dichlorophenyl urea (DCPU) binds very efficiently to the Q(B) site of PSII CC, and therefore, that moiety has been linked covalently to the headgroup of synthetic lipids. The analysis of the monolayer behavior of these DCPU-lipids has allowed us to select ones bearing long spacers for the anchoring of PSII CC. Oxygen evolution measurements demonstrated that these long-spacer DCPU-lipids specifically bind to PSII CC and inhibit electron transfer. With the use of atomic force microscopy (AFM) and scanning near-field optical microscopy (SNOM), it was possible to visualize domains of PSII CC bound to DCPU-lipid monolayers. SNOM imaging has enabled us to confirm that domains observed by AFM were composed of PSII CC. Indeed, the SNOM topography images presented similar domains as those observed by AFM, but in addition, it allowed us to determine that these domains are fluorescent. Electron microscopy of these domains, however, has shown that the bound PSII CC was not crystalline. PMID:11423438

Trudel, E; Gallant, J; Mons, S; Mioskowski, C; Lebeau, L; Jeuris, K; Foubert, P; De Schryver, F; Salesse, C

2001-01-01

240

Alginate/Nanohydroxyapatite Scaffolds with Designed Core/Shell Structures Fabricated by 3D Plotting and in Situ Mineralization for Bone Tissue Engineering.  

PubMed

Composite scaffolds, especially polymer/hydroxyapatite (HAP) composite scaffolds with predesigned structures, are promising materials for bone tissue engineering. Various methods including direct mixing of HAP powder with polymers or incubating polymer scaffolds in simulated body fluid for preparing polymer/HAP composite scaffolds are either uncontrolled or require long times of incubation. In this work, alginate/nano-HAP composite scaffolds with designed pore parameters and core/shell structures were fabricated using 3D plotting technique and in situ mineralization under mild conditions (at room temperature and without the use of any organic solvents). Light microscopy, scanning electron microscopy, microcomputer tomography, X-ray diffraction, and Fourier transform infrared spectroscopy were applied to characterize the fabricated scaffolds. Mechanical properties and protein delivery of the scaffolds were evaluated, as well as the cell response to the scaffolds by culturing human bone-marrow-derived mesenchymal stem cells (hBMSC). The obtained data indicate that this method is suitable to fabricate alginate/nano-HAP composite scaffolds with a layer of nano-HAP, coating the surface of the alginate strands homogeneously and completely. The surface mineralization enhanced the mechanical properties and improved the cell attachment and spreading, as well as supported sustaining protein release, compared to pure alginate scaffolds without nano-HAP shell layer. The results demonstrated that the method provides an interesting option for bone tissue engineering application. PMID:25761464

Luo, Yongxiang; Lode, Anja; Wu, Chengtie; Chang, Jiang; Gelinsky, Michael

2015-04-01

241

Core-Noise  

NASA Technical Reports Server (NTRS)

This presentation is a technical progress report and near-term outlook for NASA-internal and NASA-sponsored external work on core (combustor and turbine) noise funded by the Fundamental Aeronautics Program Subsonic Fixed Wing (SFW) Project. Sections of the presentation cover: the SFW system level noise metrics for the 2015, 2020, and 2025 timeframes; the emerging importance of core noise and its relevance to the SFW Reduced-Noise-Aircraft Technical Challenge; the current research activities in the core-noise area, with some additional details given about the development of a high-fidelity combustion-noise prediction capability; the need for a core-noise diagnostic capability to generate benchmark data for validation of both high-fidelity work and improved models, as well as testing of future noise-reduction technologies; relevant existing core-noise tests using real engines and auxiliary power units; and examples of possible scenarios for a future diagnostic facility. The NASA Fundamental Aeronautics Program has the principal objective of overcoming today's national challenges in air transportation. The SFW Reduced-Noise-Aircraft Technical Challenge aims to enable concepts and technologies to dramatically reduce the perceived aircraft noise outside of airport boundaries. This reduction of aircraft noise is critical for enabling the anticipated large increase in future air traffic. Noise generated in the jet engine core, by sources such as the compressor, combustor, and turbine, can be a significant contribution to the overall noise signature at low-power conditions, typical of approach flight. At high engine power during takeoff, jet and fan noise have traditionally dominated over core noise. However, current design trends and expected technological advances in engine-cycle design as well as noise-reduction methods are likely to reduce non-core noise even at engine-power points higher than approach. In addition, future low-emission combustor designs could increase the combustion-noise component. The trend towards high-power-density cores also means that the noise generated in the low-pressure turbine will likely increase. Consequently, the combined result from these emerging changes will be to elevate the overall importance of turbomachinery core noise, which will need to be addressed in order to meet future noise goals.

Hultgren, Lennart S.

2010-01-01

242

(w13) Institutional Core Management  

PubMed Central

This workshop session will focus on issues related to Institutional Core Management, in response to the national conversation evolving around research core facility issues and management. The workshop will be formatted as an experts' panel; each participant currently plays an important role in supporting and developing research core resources at an institutional level. Some of the topics to be discussed include: (1) Core Consolidation — one size fits all? (2) Bottom-up vs. top-down management, advantages and disadvantages of centrally managed cores. (3) Performance metrics and impacts on professional development, core infrastructure support and improved operations. (4) Impacts of NIH-NCRR programs on improving access to research resources, including core facilities. We also plan to highlight the new Core Administrators Network Coordinating (CAN). In response to an emerging trend to centralize the oversight of research core facilities, ABRF has fostered development of this network and a new committee: the Core Administrators Network-Coordinating Committee (CAN-CC). The committee seeks input and participation from scientists, administrators and others with an interest in issues related to the administration of research core facilities which, by the nature of their service role, must interface with multiple constituencies within a research enterprise. Today many institutions have established administrative positions designed to assist core facilities with management of economic, regulatory and performance issues. In order to facilitate greater interaction between and among core scientists and administrators, the mission of the CAN-CC is to contribute to the common interests of core administrators, and promote interactions with core scientists in a collegial and productive manner. The specific goals of the Core Administrators Network Coordinating Committee (CANCC) are: to identify and reach out to our target community; provide opportunities for networking; and assess goals for program focus and development.

Turpen, P.; Farber, G.K.; Mische, S.; Alexander, P.; Auger, J.; Meyn, S.

2011-01-01

243

Core Competencies. SPEC Kit.  

ERIC Educational Resources Information Center

This SPEC (Systems and Procedures Exchange Center) Kit presents the results of a survey of Association of Research Libraries (ARL) member libraries designed to investigate the status of core competencies (i.e., the skills, knowledge, abilities, and attributes that employees across an organization are expected to have to contribute successfully…

McNeil, Beth, Comp.

2002-01-01

244

The logical core architecture  

Microsoft Academic Search

Molecular nanotechnology (MNT) promises new functions for engineered systems, such as fairly general purpose fabrication and disassembly. Systems designed afresh to take advantage of these new functions should offer original architectures. One compelling example is the `logical core architecture', which uses subsystems providing general purpose manufacturing to enable a long-lived, very flexible system. This paper provides motivation for the logical

Tom McKendree

1998-01-01

245

Design analysis of the molten core confinement within the reactor vessel in the case of severe accidents at nuclear power plants equipped with a reactor of the VVER type  

NASA Astrophysics Data System (ADS)

The present paper reports the results of the preliminary design estimate of the behavior of the core melt in vessels of reactors of the VVER-600 and VVER-1300 types (a standard optimized and informative nuclear power unit based on VVER technology—VVER TOI) in the case of beyond-design-basis severe accidents. The basic processes determining the state of the core melt in the reactor vessel are analyzed. The concept of molten core confinement within the vessel based on the idea of outside cooling is discussed. Basic assumptions and models, as well as the results of calculation of the interaction between molten materials of the core and the wall of the reactor vessel performed by means of the SOCRAT severe accident code, are presented and discussed. On the basis of the data obtained, the requirements on the operation of the safety systems are determined, upon the fulfillment of which there will appear potential prerequisites for implementing the concept of the confinement of the core melt within the reactor in cases of severe accidents at nuclear power plants equipped with VVER reactors.

Zvonaryov, Yu. A.; Budaev, M. A.; Volchek, A. M.; Gorbaev, V. A.; Zagryazkin, V. N.; Kiselyov, N. P.; Kobzar', V. L.; Konobeev, A. V.; Tsurikov, D. F.

2013-12-01

246

Core Noise - Increasing Importance  

NASA Technical Reports Server (NTRS)

This presentation is a technical summary of and outlook for NASA-internal and NASA-sponsored external research on core (combustor and turbine) noise funded by the Fundamental Aeronautics Program Subsonic Fixed Wing (SFW) Project. Sections of the presentation cover: the SFW system-level noise metrics for the 2015, 2020, and 2025 timeframes; turbofan design trends and their aeroacoustic implications; the emerging importance of core noise and its relevance to the SFW Reduced-Perceived-Noise Technical Challenge; and the current research activities in the core-noise area, with additional details given about the development of a high-fidelity combustor-noise prediction capability as well as activities supporting the development of improved reduced-order, physics-based models for combustor-noise prediction. The need for benchmark data for validation of high-fidelity and modeling work and the value of a potential future diagnostic facility for testing of core-noise-reduction concepts are indicated. The NASA Fundamental Aeronautics Program has the principal objective of overcoming today's national challenges in air transportation. The SFW Reduced-Perceived-Noise Technical Challenge aims to develop concepts and technologies to dramatically reduce the perceived aircraft noise outside of airport boundaries. This reduction of aircraft noise is critical to enabling the anticipated large increase in future air traffic. Noise generated in the jet engine core, by sources such as the compressor, combustor, and turbine, can be a significant contribution to the overall noise signature at low-power conditions, typical of approach flight. At high engine power during takeoff, jet and fan noise have traditionally dominated over core noise. However, current design trends and expected technological advances in engine-cycle design as well as noise-reduction methods are likely to reduce non-core noise even at engine-power points higher than approach. In addition, future low-emission combustor designs could increase the combustion-noise component. The trend towards high-power-density cores also means that the noise generated in the low-pressure turbine will likely increase. Consequently, the combined result from these emerging changes will be to elevate the overall importance of turbomachinery core noise, which will need to be addressed in order to meet future noise goals.

Hultgren, Lennart S.

2011-01-01

247

MCNP LWR Core Generator  

SciTech Connect

The reactor core input generator allows for MCNP input files to be tailored to design specifications and generated in seconds. Full reactor models can now easily be created by specifying a small set of parameters and generating an MCNP input for a full reactor core. Axial zoning of the core will allow for density variation in the fuel and moderator, with pin-by-pin fidelity, so that BWR cores can more accurately be modeled. LWR core work in progress: (1) Reflectivity option for specifying 1/4, 1/2, or full core simulation; (2) Axial zoning for moderator densities that vary with height; (3) Generating multiple types of assemblies for different fuel enrichments; and (4) Parameters for specifying BWR box walls. Fuel pin work in progress: (1) Radial and azimuthal zoning for generating further unique materials in fuel rods; (2) Options for specifying different types of fuel for MOX or multiple burn assemblies; (3) Additional options for replacing fuel rods with burnable poison rods; and (4) Control rod/blade modeling.

Fischer, Noah A. [Los Alamos National Laboratory

2012-08-14

248

Cellular Truss Core Sandwich Structures  

Microsoft Academic Search

Sandwich structures with open cell truss cores are a relatively new class of multifunctional material systems that can be made using affordable deformation, assembly and joining processes. A variety of cellular core architectures have recently been made from wrought metal alloys using inexpensive textile and perforated sheet methods. Here, the design, fabrication and properties for these types of structures is

David J. Sypeck

2005-01-01

249

Saturation current spikes eliminated in saturable core transformers  

NASA Technical Reports Server (NTRS)

Unsaturating composite magnetic core transformer, consisting of two separate parallel cores designed so impending core saturation causes signal generation, terminates high current spike in converter primary circuit. Simplified waveform, demonstrates transformer effectiveness in eliminating current spikes.

Schwarz, F. C.

1971-01-01

250

Testing embedded-core based system chips  

Microsoft Academic Search

Advances in semiconductor process and design technology enable the design of complex system chips. Traditional IC design, in which every circuit is designed from scratch and reuse is limited to standard-cell libraries, is more and more replaced by a design style based on embedding large reusable modules, the so-called cores. This core-based design poses a series of new challenges, especially

Yervant Zorian; Erik Jan Marinissen; Sujit Dey

1998-01-01

251

High-quality SnO2@SnS2 core-shell heterojunctions: Designed construction, mechanism and photovoltaic applications  

NASA Astrophysics Data System (ADS)

High-quality SnO2@SnS2 core-shell heterojunctions have been constructed through sulfurization of SnO2 nanoflowers self-sacrificial templates with H2S gas at relatively low temperature in this paper. The unreacted SnO2 core and the in-situ synthesized SnS2 shell are in good crystallinity with a low lattice mismatch interface. The formation mechanism of the core-shell heterostructures have been examined by experiments and theoretic computation from the perspectives of both adsorption and diffusion. When used as photoanode in all-solid-state semiconductor-sensitized solar cells, the SnO2@SnS2 core-shell heterojunctions based hybrid solar cell shows a promising conversion efficiency of 1.45% under 1 sun illumination, which is over 5 times than that of SnS2 quantum dot sensitized SnO2 electrode made by the common chemistry bath deposition method. The enhanced photovoltaic performance is contributed to the unique structure of SnO2@SnS2 core-shell heterojunctions which provide highly covered sensitizers and favored interface for suppressing the charge recombination from SnO2 to electrolyte. This strategy and understanding can be extended to other nanostructure core-shell architecture and fields.

Liu, Ming; Yang, Junyou; Qu, Qiuliang; Zhu, Pinwen; Li, Weixin

2015-01-01

252

Core Noise Reduction  

NASA Technical Reports Server (NTRS)

This presentation is a technical summary of and outlook for NASA-internal and NASA-sponsored external research on core (combustor and turbine) noise funded by the Fundamental Aeronautics Program Subsonic Fixed Wing (SFW) Project. Sections of the presentation cover: the SFW system-level noise metrics for the 2015, 2020, and 2025 timeframes; turbofan design trends and their aeroacoustic implications; the emerging importance of core noise and its relevance to the SFW Reduce-Perceived-Noise Technical Challenge; and the current research activities in the core noise area. Recent work1 on the turbine-transmission loss of combustor noise is briefly described, two2,3 new NRA efforts in the core-noise area are outlined, and an effort to develop CMC-based acoustic liners for broadband noise reduction suitable for turbofan-core application is delineated. The NASA Fundamental Aeronautics Program has the principal objective of overcoming today's national challenges in air transportation. The reduction of aircraft noise is critical to enabling the anticipated large increase in future air traffic. The Subsonic Fixed Wing Project's Reduce-Perceived-Noise Technical Challenge aims to develop concepts and technologies to dramatically reduce the perceived aircraft noise outside of airport boundaries.

Hultgren, Lennart S.

2011-01-01

253

Engineering Technology Core (ET Core) Guide  

NSDL National Science Digital Library

"The ET Core is designed to prepare students for the study of courses specific to any engineering technology major. The curriculum provides hands-on work with technology and workplace relevance as students complete their study of physics, communications, and mathematics (through introductory calculus)." In this 140-page PDF, visitors will find an introduction to the course, the competencies it covers, equipment needed, and detailed instructions for all sixteen modules. The modules cover all sorts of engineering technology including Electrical, Thermal, Mechanical, Fluids, Optics, and Materials. Each module also contains any students handouts necessary to teach it.

254

Ethics CORE  

NSDL National Science Digital Library

The Ethics CORE Digital Library, funded by the National Science Foundation, "brings together information on best practices in research, ethics instruction and responding to ethical problems that arise in research and professional life." It's a remarkable site where visitors can make their way through ethics resources for dozens of different professions and activities. The Resources by Discipline area is a great place to start. Here you will find materials related to the biological sciences, business, computer & information science, along with 14 additional disciplines. The Current News area is a great place to learn about the latest updates from the field. Of note, these pieces can easily be used in the classroom or shared with colleagues. The dynamism of the site can be found at the Interact with Ethics CORE area. Active learning exercises can be found here, along with instructional materials and visitors' own lessons learned.

255

Fissioning Plasma Core Reactor  

NASA Technical Reports Server (NTRS)

Institute for Scientific Research, Inc. (ISR) research program consist of: 1.Study core physics by adapting existing codes: MCNP4C - Monte Carlo code; COMBINE/VENTURE - diffusion theory; SCALE4 - Monte Carlo, with many utility codes. 2. Determine feasibility and study major design parameters: fuel selection, temperature and reflector sizing. 3. Study reactor kinetics: develop QCALC1 to model point kinetics; study dynamic behavior of the power release.

Albright, Dennis; Butler, Carey; West, Nicole; Cole, John W. (Technical Monitor)

2002-01-01

256

CopperCore Service Integration  

ERIC Educational Resources Information Center

In an e-learning environment there is a need to integrate various e-learning services like assessment services, collaboration services, learning design services and communication services. In this article we present the design and implementation of a generic integrative service framework, called CopperCore Service Integration (CCSI). We will…

Vogten, Hubert; Martens, Harrie; Nadolski, Rob; Tattersall, Colin; van Rosmalen, Peter; Koper, Rob

2007-01-01

257

Curriculum Design, Development, and Implementation in an Era of Common Core State Standards. Summary Report of a Conference (Arlington, Virginia, August 1-3, 2010)  

ERIC Educational Resources Information Center

In June 2010, the National Governor's Association and the Council of Chief State School Officers published "Common Core State Standards" (CCSS) for K-12 mathematics. Forty-eight states collaborated in the development of CCSS and, to date, 34 states have officially adopted CCSS to replace existing state standards. CCSS presents an opportunity for…

Confrey, Jere; Krupa, Erin

2010-01-01

258

Uranium droplet core nuclear rocket  

NASA Technical Reports Server (NTRS)

Uranium droplet nuclear rocket is conceptually designed to utilize the broad temperature range ofthe liquid phase of metallic uranium in droplet configuration which maximizes the energy transfer area per unit fuel volume. In a baseline system dissociated hydrogen at 100 bar is heated to 6000 K, providing 2000 second of Isp. Fission fragments and intense radian field enhance the dissociation of molecular hydrogen beyond the equilibrium thermodynamic level. Uranium droplets in the core are confined and separated by an axisymmetric vortex flow generated by high velocity tangential injection of hydrogen in the mid-core regions. Droplet uranium flow to the core is controlled and adjusted by a twin flow nozzle injection system.

Anghaie, Samim

1991-01-01

259

A scaling study of the natural circulation flow of the ex-vessel core catcher cooling system of EU-APR1400 for designing a scale-down test facility for design verification  

SciTech Connect

In this paper a scaling study on the steady state natural circulation flow along the flow path of the ex vessel core catcher cooling system of EU-APR1400 is described, and the scaling criteria for reproducing the same steady state thermalhydraulic characteristics of the natural circulation flow as a prototype core catcher cooling system in the scale-down test facility are derived in terms of the down-comer pipe diameter and orifice resistance. (authors)

Rhee, B. W.; Ha, K. S.; Park, R. J.; Song, J. H. [Korea Atomic Energy Research Inst., 1045 Daedukdaero, Yusong-Gu, Daejon (Korea, Republic of); Revankar, S. T. [Div. of Advanced Nuclear Engineering, POSTECH, Pohang (Korea, Republic of)

2012-07-01

260

A study on the effect of various design parameters on the natural circulation flow rate of the ex-vessel core catcher cooling system of EU-APR1400  

SciTech Connect

In this paper, a study on the effect of various design parameters such as the channel gap width, heat flux distribution, down-comer pipe size and two-phase flow slip ratio on the natural circulation flow rate is performed based on a physical model for a natural circulation flow along the flow path of the ex-vessel core catcher cooling system of an EU-APR1400, and these effects on the natural circulation flow rate are analyzed and compared with the minimum flow rate required for the safe operation of the system. (authors)

Rhee, B. W.; Ha, K. S.; Park, R. J.; Song, J. H. [Korea Atomic Energy Research Inst., 1045 Daedukdaero, Yusong-Gu, Daejon (Korea, Republic of)

2012-07-01

261

Designing a core IT artefact for Knowledge Management Systems using participatory action research in a government and a non-government organisation  

Microsoft Academic Search

There is a growing interest in the application of information technologies (IT) for Knowledge Management (KM) in the public sector; there is, however, a dearth of research on the design and development of effective, integrated Knowledge Management Systems (KMS). Consequently, public sector organisations and private sector enterprises are offered little in the way of guidance in designing KMS from the

Tom Butler; Joseph Feller; Andrew Pope; Bill Emerson; Ciaran Murphy

2008-01-01

262

Core Recursive Hierarchical Image Segmentation  

NASA Technical Reports Server (NTRS)

The Recursive Hierarchical Image Segmentation (RHSEG) software has been repackaged to provide a version of the RHSEG software that is not subject to patent restrictions and that can be released to the general public through NASA GSFC's Open Source release process. Like the Core HSEG Software Package, this Core RHSEG Software Package also includes a visualization program called HSEGViewer along with a utility program HSEGReader. It also includes an additional utility program called HSEGExtract. The unique feature of the Core RHSEG package is that it is a repackaging of the RHSEG technology designed to specifically avoid the inclusion of the certain software technology. Unlike the Core HSEG package, it includes the recursive portions of the technology, but does not include processing window artifact elimination technology.

Tilton, James

2011-01-01

263

Diagnostic Performance of Combined Non-invasive Coronary Angiography and Myocardial Perfusion Imaging Using 320 Row Detector Computed Tomography: Design and Implementation of the CORE320 Multicenter, Multinational Diagnostic Study  

PubMed Central

Multi-detector coronary computed tomography angiography (CTA) is a promising modality for widespread clinical application because of its non-invasive nature and high diagnostic accuracy as found in previous studies using 64 to 320 simultaneous detector rows. It is, however, limited in its ability to detect myocardial ischemia. In this manuscript we describe the design of the CORE320 study (“Combined Coronary Atherosclerosis and Myocardial Perfusion Evaluation Using 320 Detector Row Computed Tomography”). This prospective, multicenter, multinational study is unique in that it is designed to assess the diagnostic performance of combined 320-row CTA and myocardial CT perfusion imaging (CTP) in comparison to the combination of invasive coronary angiography and single photon emission computed tomography myocardial perfusion imaging (SPECT-MPI). The trial is being performed at 16 medical centers located in 8 countries worldwide. Computed tomography has the potential to assess both anatomy and physiology in a single imaging session. The co-primary aims of the CORE320 study is to define the per-patient diagnostic accuracy of the combination of coronary CTA and myocardial CTP to detect physiologically significant coronary artery disease compared to 1) the combination of conventional coronary angiography and SPECT-MPI and 2) conventional coronary angiography alone. If successful, the technology could revolutionize the management of patients with symptomatic CAD. PMID:22146496

Vavere, Andrea L.; Simon, Gregory G.; George, Richard T.; Rochitte, Carlos E.; Arai, Andrew E.; Miller, Julie M.; Di Carli, Marcello; Zadeh, Armin A.; Dewey, Marc; Niinuma, Hiroyuki; Laham, Roger; Rybicki, Frank J.; Schuijf, Joanne D.; Paul, Narinder; Hoe, John; Kuribyashi, Sachio; Sakuma, Hajime; Nomura, Cesar; Yaw, Tan Swee; Kofoed, Klaus F.; Yoshioka, Kunihiro; Clouse, Melvin E.; Brinker, Jeffrey; Cox, Christopher; Lima, Joao AC

2013-01-01

264

Design.  

ERIC Educational Resources Information Center

Provides an annotated bibliography of resources on this month's theme "Design" for K-8 language arts, art and architecture, music and dance, science, math, social studies, health, and physical education. Includes Web sites, CD-ROMs and software, videos, books, audiotapes, magazines, professional resources and classroom activities. Features Art…

Online-Offline, 1998

1998-01-01

265

Module name Description Core Modules  

E-print Network

for future marketing strategies and plans. Managing the Corporate Brand This module is designed to enable youModule name Description Core Modules Strategic Perspectives in Marketing Learn to think strategically and understand how strategic marketing decisions are formulated and executed in the global

Evans, Paul

266

Methodology for embedded transport core calculation  

NASA Astrophysics Data System (ADS)

The progress in the Nuclear Engineering field leads to developing new generations of Nuclear Power Plants (NPP) with complex rector core designs, such as cores loaded partially with mixed-oxide (MOX) fuel, high burn-up loadings, and cores with advanced designs of fuel assemblies and control rods. Such heterogeneous cores introduce challenges for the diffusion theory that has been used for several decades for calculations of the current Pressurized Water Rector (PWR) cores. To address the difficulties the diffusion approximation encounters new core calculation methodologies need to be developed by improving accuracy, while preserving efficiency of the current reactor core calculations. In this thesis, an advanced core calculation methodology is introduced, based on embedded transport calculations. Two different approaches are investigated. The first approach is based on embedded finite element (FEM), simplified P3 approximation (SP3), fuel assembly (FA) homogenization calculation within the framework of the diffusion core calculation with NEM code (Nodal Expansion Method). The second approach involves embedded FA lattice physics eigenvalue calculation based on collision probability method (CPM) again within the framework of the NEM diffusion core calculation. The second approach is superior to the first because most of the uncertainties introduced by the off-line cross-section generation are eliminated.

Ivanov, Boyan D.

267

Journal papers 1. F. Wols, J.L. Kloosterman, D. Lathouwers and T.H.J.J. van der Hagen, Core design and fuel  

E-print Network

and breeding gain of a moderated molten salt reactor, Annals of Nuclear Energy 43 (2012) 19-25. 13. M. Rohde, C definitions and their application to the optimization of a Molten Salt Reactor design. Annals of Nuclear and fuel management of a thorium-breeder pebble bed high-temperature reactor, Nuclear Technology 186 (2014

268

Velocity-Controlled Magnetic Bearings with Solid Cores  

NASA Technical Reports Server (NTRS)

A methodology for designing velocity-controlled magnetic bearings with laminated cores has been extended to those with solid cores. The eddy-current effect of the solid cores is modeled as an opposing magnetomotive force. The bearing control dynamics is formulated in a dimensionless fashion which can be readily reviewed on a root-locus plot for stability. This facilitates the controller design and tuning process for solid core magnetic bearings using no displacement sensors.

Chen, H. Ming; Walton, James

1996-01-01

269

Liquid sodium model of Earth's outer core  

Microsoft Academic Search

Convective motions in Earth's outer core are responsible for the generation of the geomagnetic field. We present liquid sodium convection experiments in a spherical vessel, designed to model the convective state of Earth's outer core. Heat transfer, zonal fluid velocities, and properties of temperature fluctuations were measured for different rotation rates O and temperature drops DeltaT across the convecting sodium.

Woodrow Shew

2004-01-01

270

Core-core and core-valence correlation  

NASA Technical Reports Server (NTRS)

The effect of (1s) core correlation on properties and energy separations was analyzed using full configuration-interaction (FCI) calculations. The Be 1 S - 1 P, the C 3 P - 5 S and CH+ 1 Sigma + or - 1 Pi separations, and CH+ spectroscopic constants, dipole moment and 1 Sigma + - 1 Pi transition dipole moment were studied. The results of the FCI calculations are compared to those obtained using approximate methods. In addition, the generation of atomic natural orbital (ANO) basis sets, as a method for contracting a primitive basis set for both valence and core correlation, is discussed. When both core-core and core-valence correlation are included in the calculation, no suitable truncated CI approach consistently reproduces the FCI, and contraction of the basis set is very difficult. If the (nearly constant) core-core correlation is eliminated, and only the core-valence correlation is included, CASSCF/MRCI approached reproduce the FCI results and basis set contraction is significantly easier.

Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.; Taylor, Peter R.

1988-01-01

271

Long Valley Coring Project, Inyo County, California, 1998, preliminary stratigraphy and images of recovered core  

USGS Publications Warehouse

Phase III of the Long Valley Exploratory Well, the Long Valley Coring Project, obtained continuous core between the depths of 7,180 and 9,831 ft (2,188 to 2,996 meters) during the summer of 1998. This report contains a compendium of information designed to facilitate post-drilling research focussed on the study of the core. Included are a preliminary stratigraphic column compiled primarily from field observations and a general description of well lithology for the Phase III drilling interval. Also included are high-resolution digital photographs of every core box (10 feet per box) as well as scanned images of pieces of recovered core. The user can easily move from the stratigraphic column to corresponding core box photographs for any depth. From there, compressed, "unrolled" images of the individual core pieces (core scans) can be accessed. Those interested in higher-resolution core scans can go to archive CD-ROMs stored at a number of locations specified herein. All core is stored at the USGS Core Research Center in Denver, Colorado where it is available to researchers following the protocol described in this report. Preliminary examination of core provided by this report and the archive CD-ROMs should assist researchers in narrowing their choices when requesting core splits.

Sackett, Penelope C.; McConnell, Vicki S.; Roach, Angela L.; Priest, Susan S.; Sass, John H.

1999-01-01

272

Multicore Performance Optimization Using Partner Cores  

E-print Network

As the push for parallelism continues to increase the number of cores on a chip, and add to the complexity of system design, the task of optimizing performance at the application level becomes nearly impossible for the ...

Lau, Eric

2011-03-25

273

Compilation Techniques for Core Plus FPGA Systems  

NASA Technical Reports Server (NTRS)

The overall system architecture targeted in this study is a core-plus-fpga design, which is composed of a core VLIW DSP with on-chip memory and a set of special-purpose functional units implemented using FPGAs. A figure is given which shows the overall organization of the core-plus-fpga system. It is important to note that this architecture is relatively simple in concept and can be built from off-the-shelf commercial components, such as one of the Texas Instruments 320C6x family of DSPs for the core processor.

Conte, Tom

2001-01-01

274

De novo design of a non-natural fold for an iron-sulfur protein: alpha-helical coiled-coil with a four-iron four-sulfur cluster binding site in its central core.  

PubMed

Using a 'metal-first' approach, we computationally designed, prepared, and characterized a four-iron four-sulfur (Fe(4)S(4)) cluster protein with a non-natural alpha-helical coiled-coil fold. The novelty of this fold lies in the placement of a Fe(4)S(4) cluster within the hydrophobic core of a four-helix bundle, making it unique among previous iron-sulfur (FeS) protein designs, and different from known natural FeS proteins. The apoprotein, recombinantly expressed and purified from E. coli, readily self-assembles with Fe(4)S(4) clusters in vitro. UV-Vis absorption and CD spectroscopy, elemental analysis, gel filtration, and analytical ultracentrifugation confirm that the protein is folded and assembled as designed, namely, alpha-helical coiled-coil binding a single Fe(4)S(4) cluster. Dithionite-reduced holoprotein samples have characteristic rhombic EPR spectra, typical of low-potential, [Fe(4)S(4)](+) (S=1/2), with g values of g(zy)=(1.970, 1.975), and g(x)=2.053. The temperature, and power dependence of the signal intensity were also characteristic of [Fe(4)S(4)](+) clusters with very efficient spin relaxation, but almost without any interaction between adjacent clusters. The new design is very promising although optimization is required, particularly for preventing aggregation, and adding second shell interactions to stabilize the reduced state. Its main advantage is its extendibility into a multi-FeS cluster protein by simply duplicating and translating the binding site along the coiled-coil axis. This opens new possibilities for designing protein-embedded redox chains that may be used as "wires" for coupling any given set of redox enzymes. PMID:20035711

Grzyb, Joanna; Xu, Fei; Weiner, Lev; Reijerse, Eduard J; Lubitz, Wolfgang; Nanda, Vikas; Noy, Dror

2010-03-01

275

Academic Rigor: The Core of the Core  

ERIC Educational Resources Information Center

Some educators see the Common Core State Standards as reason for stress, most recognize the positive possibilities associated with them and are willing to make the professional commitment to implementing them so that academic rigor for all students will increase. But business leaders, parents, and the authors of the Common Core are not the only…

Brunner, Judy

2013-01-01

276

Droplet Core Nuclear Rocket (DCNR)  

NASA Technical Reports Server (NTRS)

The most basic design feature of the droplet core nuclear reactor is to spray liquid uranium into the core in the form of droplets on the order of five to ten microns in size, to bring the reactor to critical conditions. The liquid uranium fuel ejector is driven by hydrogen, and more hydrogen is injected from the side of the reactor to about one and a half meters from the top. High temperature hydrogen is expanded through a nozzle to produce thrust. The hydrogen pressure in the system can be somewhere between 50 and 500 atmospheres; the higher pressure is more desirable. In the lower core region, hydrogen is tangentially injected to serve two purposes: (1) to provide a swirling flow to protect the wall from impingement of hot uranium droplets: (2) to generate a vortex flow that can be used for fuel separation. The reactor is designed to maximize the energy generation in the upper region of the core. The system can result in and Isp of 2000 per second, and a thrust-to-weight ratio of 1.6 for the shielded reactor. The nuclear engine system can reduce the Mars mission duration to less than 200 days. It can reduce the hydrogen consumption by a factor of 2 to 3, which reduces the hydrogen load by about 130 to 150 metric tons.

Anghaie, Samim

1991-01-01

277

"CanCore": In Canada and around the World  

ERIC Educational Resources Information Center

In this article, the author discusses "CanCore," a learning resource metadata initiative funded by Industry Canada and supported by Athabasca University, Alberta, and TeleUniversite du Quebec, and describes the increasing range of international uses of the "CanCore" metadata for the indexing of learning objects. "CanCore" is designed to facilitate…

Friesen, Norm

2005-01-01

278

Institutional Management of Core Facilities during Challenging Financial Times  

PubMed Central

The economic downturn is likely to have lasting effects on institutions of higher education, prioritizing proactive institutional leadership and planning. Although by design, core research facilities are more efficient and effective than supporting individual pieces of research equipment, cores can have significant underlying financial requirements and challenges. This paper explores several possible institutional approaches to managing core facilities during challenging financial times. PMID:22131887

Haley, Rand

2011-01-01

279

Design of meso-TiO2@MnO(x)-CeO(x)/CNTs with a core-shell structure as DeNO(x) catalysts: promotion of activity, stability and SO2-tolerance.  

PubMed

Developing low-temperature deNOx catalysts with high catalytic activity, SO2-tolerance and stability is highly desirable but remains challenging. Herein, by coating the mesoporous TiO2 layers on carbon nanotubes (CNTs)-supported MnOx and CeOx nanoparticles (NPs), we obtained a core-shell structural deNOx catalyst with high catalytic activity, good SO2-tolerance and enhanced stability. Transmission electron microscopy, X-ray diffraction, N2 sorption, X-ray photoelectron spectroscopy, H2 temperature-programmed reduction and NH3 temperature-programmed desorption have been used to elucidate the structure and surface properties of the obtained catalysts. Both the specific surface area and chemisorbed oxygen species are enhanced by the coating of meso-TiO2 sheaths. The meso-TiO2 sheaths not only enhance the acid strength but also raise acid amounts. Moreover, there is a strong interaction among the manganese oxide, cerium oxide and meso-TiO2 sheaths. Based on these favorable properties, the meso-TiO2 coated catalyst exhibits a higher activity and more extensive operating-temperature window, compared to the uncoated catalyst. In addition, the meso-TiO2 sheaths can serve as an effective barrier to prevent the aggregation of metal oxide NPs during stability testing. As a result, the meso-TiO2 overcoated catalyst exhibits a much better stability than the uncoated one. More importantly, the meso-TiO2 sheaths can not only prevent the generation of ammonium sulfate species from blocking the active sites but also inhibit the formation of manganese sulfate, resulting in a higher SO2-tolerance. These results indicate that the design of a core-shell structure is effective to promote the performance of deNOx catalysts. PMID:23970126

Zhang, Lei; Zhang, Dengsong; Zhang, Jianping; Cai, Sixiang; Fang, Cheng; Huang, Lei; Li, Hongrui; Gao, Ruihua; Shi, Liyi

2013-10-21

280

Understanding the Impact of Multi-Core Architecture in Cluster Computing: A Case Study with Intel Dual-Core System  

E-print Network

and design a set of experiments to study the impact of multi-core architecture on cluster comput- ing. WeUnderstanding the Impact of Multi-Core Architecture in Cluster Computing: A Case Study with Intel is a growing industry trend as sin- gle core processors rapidly reach the physical limits of pos- sible

Panda, Dhabaleswar K.

281

Development and analysis for core power gamma thermometer adaptation  

SciTech Connect

The gamma thermometer (GT) has gained increasing interest to replace the local power range monitor (LPRM) and the traversing in-core probe (TIP) as the core monitoring device in new boiling water reactor (BWR) designs. The number of GTs is designed between the number of LPRMs, 4, and the number of TIPs, 24, per string, but its optimal number is yet to be determined. The authors have modified the BWR core Simulator PANACEA for analyzing the core power GT adaptation and have compared the axial core-averaged relative power distributions and two thermal limits of the GT 8- and 12-point adaptations against those of the TIP 24-point adaptation.

Ren-Tai Chiang; Leong, T. [General Electric Co., San Jose, CA (United States)

1996-12-31

282

Multi-Core Processor Memory Contention Benchmark Analysis Case Study  

NASA Technical Reports Server (NTRS)

Multi-core processors dominate current mainframe, server, and high performance computing (HPC) systems. This paper provides synthetic kernel and natural benchmark results from an HPC system at the NASA Goddard Space Flight Center that illustrate the performance impacts of multi-core (dual- and quad-core) vs. single core processor systems. Analysis of processor design, application source code, and synthetic and natural test results all indicate that multi-core processors can suffer from significant memory subsystem contention compared to similar single-core processors.

Simon, Tyler; McGalliard, James

2009-01-01

283

Banded transformer cores  

NASA Technical Reports Server (NTRS)

A banded transformer core formed by positioning a pair of mated, similar core halves on a supporting pedestal. The core halves are encircled with a strap, selectively applying tension whereby a compressive force is applied to the core edge for reducing the innate air gap. A dc magnetic field is employed in supporting the core halves during initial phases of the banding operation, while an ac magnetic field subsequently is employed for detecting dimension changes occurring in the air gaps as tension is applied to the strap.

Mclyman, C. W. T. (inventor)

1974-01-01

284

Lightweight Low Force Rotary Percussive Coring Tool for Planetary Applications  

NASA Technical Reports Server (NTRS)

A prototype low-force rotary-percussive rock coring tool for use in acquiring samples for geological surveys in future planetary missions was developed. The coring tool could eventually enable a lightweight robotic system to operate from a relatively small (less than 200 kg) mobile or fixed platform to acquire and cache Mars or other planetary rock samples for eventual return to Earth for analysis. To gain insight needed to design an integrated coring tool, the coring ability of commercially available coring bits was evaluated for effectiveness of varying key parameters: weight-on-bit, rotation speed, percussive rate and force. Trade studies were performed for different methods of breaking a core at its base and for retaining the core in a sleeve to facilitate sample transfer. This led to a custom coring tool design which incorporated coring, core breakage, core retention, and core extraction functions. The coring tool was tested on several types of rock and demonstrated the overall feasibility of this approach for robotic rock sample acquisition.

Hironaka, Ross; Stanley, Scott

2010-01-01

285

Core-Cutoff Tool  

NASA Technical Reports Server (NTRS)

A tool makes a cut perpendicular to the cylindrical axis of a core hole at a predetermined depth to free the core at that depth. The tool does not damage the surrounding material from which the core was cut, and it operates within the core-hole kerf. Coring usually begins with use of a hole saw or a hollow cylindrical abrasive cutting tool to make an annular hole that leaves the core (sometimes called the plug ) in place. In this approach to coring as practiced heretofore, the core is removed forcibly in a manner chosen to shear the core, preferably at or near the greatest depth of the core hole. Unfortunately, such forcible removal often damages both the core and the surrounding material (see Figure 1). In an alternative prior approach, especially applicable to toxic or fragile material, a core is formed and freed by means of milling operations that generate much material waste. In contrast, the present tool eliminates the damage associated with the hole-saw approach and reduces the extent of milling operations (and, hence, reduces the waste) associated with the milling approach. The present tool (see Figure 2) includes an inner sleeve and an outer sleeve and resembles the hollow cylindrical tool used to cut the core hole. The sleeves are thin enough that this tool fits within the kerf of the core hole. The inner sleeve is attached to a shaft that, in turn, can be attached to a drill motor or handle for turning the tool. This tool also includes a cutting wire attached to the distal ends of both sleeves. The cutting wire is long enough that with sufficient relative rotation of the inner and outer sleeves, the wire can cut all the way to the center of the core. The tool is inserted in the kerf until its distal end is seated at the full depth. The inner sleeve is then turned. During turning, frictional drag on the outer core pulls the cutting wire into contact with the core. The cutting force of the wire against the core increases with the tension in the wire and, hence, with the frictional drag acting on the outer sleeve. As the wire cuts toward the center of the core, the inner sleeve rotates farther with respect to the outer sleeve. Once the wire has cut to the center of the core, the tool and the core can be removed from the hole. The proper choice of cutting wire depends on the properties of the core material. For a sufficiently soft core material, a nonmetallic monofilament can be used. For a rubber-like core material, a metal wire can be used. For a harder core material, it is necessary to use an abrasive wire, and the efficiency of the tool can be increased greatly by vacuuming away the particles generated during cutting. For a core material that can readily be melted or otherwise cut by use of heat, it could be preferable to use an electrically heated cutting wire. In such a case, electric current can be supplied to the cutting wire, from an electrically isolated source, via rotating contact rings mounted on the sleeves.

Gheen, Darrell

2007-01-01

286

KSI's Cross Insulated Core Transformer Technology  

SciTech Connect

Cross Insulated Core Transformer (CCT) technology improves on Insulated Core Transformer (ICT) implementations. ICT systems are widely used in very high voltage, high power, power supply systems. In an ICT transformer ferrite core sections are insulated from their neighboring ferrite cores. Flux leakage is present at each of these insulated gaps. The flux loss is raised to the power of stages in the ICT design causing output voltage efficiency to taper off with increasing stages. KSI's CCT technology utilizes a patented technique to compensate the flux loss at each stage of an ICT system. Design equations to calculate the flux compensation capacitor value are presented. CCT provides corona free operation of the HV stack. KSI's CCT based High Voltage power supply systems offer high efficiency operation, high frequency switching, low stored energy and smaller size over comparable ICT systems.

Uhmeyer, Uwe [Kaiser Systems, Inc, 126 Sohier Road, Beverly, MA 01915 (United States)

2009-08-04

287

KSI's Cross Insulated Core Transformer Technology  

NASA Astrophysics Data System (ADS)

Cross Insulated Core Transformer (CCT) technology improves on Insulated Core Transformer (ICT) implementations. ICT systems are widely used in very high voltage, high power, power supply systems. In an ICT transformer ferrite core sections are insulated from their neighboring ferrite cores. Flux leakage is present at each of these insulated gaps. The flux loss is raised to the power of stages in the ICT design causing output voltage efficiency to taper off with increasing stages. KSI's CCT technology utilizes a patented technique to compensate the flux loss at each stage of an ICT system. Design equations to calculate the flux compensation capacitor value are presented. CCT provides corona free operation of the HV stack. KSI's CCT based High Voltage power supply systems offer high efficiency operation, high frequency switching, low stored energy and smaller size over comparable ICT systems.

Uhmeyer, Uwe

2009-08-01

288

Core Physics and Kinetics Calculations for the Fissioning Plasma Core Reactor  

NASA Technical Reports Server (NTRS)

Highly efficient, compact nuclear reactors would provide high specific impulse spacecraft propulsion. This analysis and numerical simulation effort has focused on the technical feasibility issues related to the nuclear design characteristics of a novel reactor design. The Fissioning Plasma Core Reactor (FPCR) is a shockwave-driven gaseous-core nuclear reactor, which uses Magneto Hydrodynamic effects to generate electric power to be used for propulsion. The nuclear design of the system depends on two major calculations: core physics calculations and kinetics calculations. Presently, core physics calculations have concentrated on the use of the MCNP4C code. However, initial results from other codes such as COMBINE/VENTURE and SCALE4a. are also shown. Several significant modifications were made to the ISR-developed QCALC1 kinetics analysis code. These modifications include testing the state of the core materials, an improvement to the calculation of the material properties of the core, the addition of an adiabatic core temperature model and improvement of the first order reactivity correction model. The accuracy of these modifications has been verified, and the accuracy of the point-core kinetics model used by the QCALC1 code has also been validated. Previously calculated kinetics results for the FPCR were described in the ISR report, "QCALC1: A code for FPCR Kinetics Model Feasibility Analysis" dated June 1, 2002.

Butler, C.; Albright, D.

2007-01-01

289

The CORE study protocol: a stepped wedge cluster randomised controlled trial to test a co-design technique to optimise psychosocial recovery outcomes for people affected by mental illness in the community mental health setting  

PubMed Central

Introduction User engagement in mental health service design is heralded as integral to health systems quality and performance, but does engagement improve health outcomes? This article describes the CORE study protocol, a novel stepped wedge cluster randomised controlled trial (SWCRCT) to improve psychosocial recovery outcomes for people with severe mental illness. Methods An SWCRCT with a nested process evaluation will be conducted over nearly 4?years in Victoria, Australia. 11 teams from four mental health service providers will be randomly allocated to one of three dates 9?months apart to start the intervention. The intervention, a modified version of Mental Health Experience Co-Design (MH ECO), will be delivered to 30 service users, 30 carers and 10 staff in each cluster. Outcome data will be collected at baseline (6?months) and at completion of each intervention wave. The primary outcome is improvement in recovery score using the 24-item Revised Recovery Assessment Scale for service users. Secondary outcomes are improvements to user and carer mental health and well-being using the shortened 8-item version of the WHOQOL Quality of Life scale (EUROHIS), changes to staff attitudes using the 19-item Staff Attitudes to Recovery Scale and recovery orientation of services using the 36-item Recovery Self Assessment Scale (provider version). Intervention and usual care periods will be compared using a linear mixed effects model for continuous outcomes and a generalised linear mixed effects model for binary outcomes. Participants will be analysed in the group that the cluster was assigned to at each time point. Ethics and dissemination The University of Melbourne, Human Research Ethics Committee (1340299.3) and the Federal and State Departments of Health Committees (Project 20/2014) granted ethics approval. Baseline data results will be reported in 2015 and outcomes data in 2017. Trial registration number Australian and New Zealand Clinical Trials Registry ACTRN12614000457640. PMID:25805530

Palmer, Victoria J; Chondros, Patty; Piper, Donella; Callander, Rosemary; Weavell, Wayne; Godbee, Kali; Potiriadis, Maria; Richard, Lauralie; Densely, Konstancja; Herrman, Helen; Furler, John; Pierce, David; Schuster, Tibor; Iedema, Rick; Gunn, Jane

2015-01-01

290

Double-core GMI current sensor  

Microsoft Academic Search

A novel design of the giant magnetoimpedance contactless current sensor is presented. A double-core structure is used in order to improve the temperature stability. The temperature coefficient of sensitivity and offset drift are reduced to one-half compared to the single-core sensor. The linearity error decreases by a factor of three. Further utilization of an ac biasing (up to 200 Hz)

Michal Malátek; Pavel Ripka; L. Kraus

2005-01-01

291

Double-core GMI current sensor  

Microsoft Academic Search

The design of a double-core giant magnetoimpedance (GMI) current sensor, which lowers the temperature influence and also improves linearity, is presented. The sensor consists of two ring cores made of 52 cm long CoFeSiBCr magnetoimpedance (MI) strips. In order to optimize the Ml characteristics, the ribbon was annealed at 390°C under axial field of 2400 kA\\/m. The sensor was driven

M. Malatek; P. Ripka; L. Kraus

2005-01-01

292

A core handling device for the Mars Sample Return Mission  

Microsoft Academic Search

A core handling device for use on Mars is being designed. To provide a context for the design study, it was assumed that a Mars Rover\\/Sample Return (MRSR) Mission would have the following characteristics: a year or more in length; visits by the rover to 50 or more sites; 100 or more meter-long cores being drilled by the rover; and

Owen Gwynne

1989-01-01

293

Thermal hydraulics analysis of the MIT research reactor in support of a low enrichment uranium (LEU) core conversion  

E-print Network

The MIT research reactor (MITR) is converting from the existing high enrichment uranium (HEU) core to a low enrichment uranium (LEU) core using a high-density monolithic UMo fuel. The design of an optimum LEU core for the ...

Ko, Yu-Chih, Ph. D. Massachusetts Institute of Technology

2008-01-01

294

Dublin Core Metadata Initiative  

NSDL National Science Digital Library

Dublin Core metadata has been implemented in several ways, including as HTML metatags and as database elements, as it is used in the Scout Archives (discussed in the June 20, 1997 issue of the Scout Report). The DC elements are title, author, subject, description, publisher, other contributor, date, resource type, format, resource identifier, source, language, relation, coverage, and rights management. Information about the Dublin Core Workshop Series, DC semantics and syntax, working papers, and projects that have implemented Dublin Core metadata can be found at the Dublin Core Metadata homepage.

295

ART AND DESIGN All students enrolling in the School  

E-print Network

ART AND DESIGN All students enrolling in the School of Art and Design begin their studies in a Pre-Art and Design Core program designed to introduce them to the fundamentals of the field. Pre-Art and Design Core-faculty and student-to-student interaction. Faculty in the Pre-Art and Design Core program work closely with students

296

Core-core and core-valence correlation  

NASA Technical Reports Server (NTRS)

The effect of 1s core correlation on properties and energy separations are analyzed using full configuration-interaction (FCI) calculations. The Be1S - 1P, the C 3P - 5S,m and CH(+) 1Sigma(+) - 1Pi separations, and CH(+) spectroscopic constants, dipole moment, and 1Sigma(+) - 1Pi transition dipole moment have been studied. The results of the FCI calculations are compared to those obtained using approximate methods.

Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.; Taylor, Peter R.

1988-01-01

297

Design of meso-TiO2@MnOx-CeOx/CNTs with a core-shell structure as DeNOx catalysts: promotion of activity, stability and SO2-tolerance  

NASA Astrophysics Data System (ADS)

Developing low-temperature deNOx catalysts with high catalytic activity, SO2-tolerance and stability is highly desirable but remains challenging. Herein, by coating the mesoporous TiO2 layers on carbon nanotubes (CNTs)-supported MnOx and CeOx nanoparticles (NPs), we obtained a core-shell structural deNOx catalyst with high catalytic activity, good SO2-tolerance and enhanced stability. Transmission electron microscopy, X-ray diffraction, N2 sorption, X-ray photoelectron spectroscopy, H2 temperature-programmed reduction and NH3 temperature-programmed desorption have been used to elucidate the structure and surface properties of the obtained catalysts. Both the specific surface area and chemisorbed oxygen species are enhanced by the coating of meso-TiO2 sheaths. The meso-TiO2 sheaths not only enhance the acid strength but also raise acid amounts. Moreover, there is a strong interaction among the manganese oxide, cerium oxide and meso-TiO2 sheaths. Based on these favorable properties, the meso-TiO2 coated catalyst exhibits a higher activity and more extensive operating-temperature window, compared to the uncoated catalyst. In addition, the meso-TiO2 sheaths can serve as an effective barrier to prevent the aggregation of metal oxide NPs during stability testing. As a result, the meso-TiO2 overcoated catalyst exhibits a much better stability than the uncoated one. More importantly, the meso-TiO2 sheaths can not only prevent the generation of ammonium sulfate species from blocking the active sites but also inhibit the formation of manganese sulfate, resulting in a higher SO2-tolerance. These results indicate that the design of a core-shell structure is effective to promote the performance of deNOx catalysts.Developing low-temperature deNOx catalysts with high catalytic activity, SO2-tolerance and stability is highly desirable but remains challenging. Herein, by coating the mesoporous TiO2 layers on carbon nanotubes (CNTs)-supported MnOx and CeOx nanoparticles (NPs), we obtained a core-shell structural deNOx catalyst with high catalytic activity, good SO2-tolerance and enhanced stability. Transmission electron microscopy, X-ray diffraction, N2 sorption, X-ray photoelectron spectroscopy, H2 temperature-programmed reduction and NH3 temperature-programmed desorption have been used to elucidate the structure and surface properties of the obtained catalysts. Both the specific surface area and chemisorbed oxygen species are enhanced by the coating of meso-TiO2 sheaths. The meso-TiO2 sheaths not only enhance the acid strength but also raise acid amounts. Moreover, there is a strong interaction among the manganese oxide, cerium oxide and meso-TiO2 sheaths. Based on these favorable properties, the meso-TiO2 coated catalyst exhibits a higher activity and more extensive operating-temperature window, compared to the uncoated catalyst. In addition, the meso-TiO2 sheaths can serve as an effective barrier to prevent the aggregation of metal oxide NPs during stability testing. As a result, the meso-TiO2 overcoated catalyst exhibits a much better stability than the uncoated one. More importantly, the meso-TiO2 sheaths can not only prevent the generation of ammonium sulfate species from blocking the active sites but also inhibit the formation of manganese sulfate, resulting in a higher SO2-tolerance. These results indicate that the design of a core-shell structure is effective to promote the performance of deNOx catalysts. Electronic supplementary information (ESI) available: EDS analysis of MnCe/CNTs, XPS spectrum of meso-TiO2@MnCe/CNTs and TEM images of the catalysts after stability test. See DOI: 10.1039/c3nr03150k

Zhang, Lei; Zhang, Dengsong; Zhang, Jianping; Cai, Sixiang; Fang, Cheng; Huang, Lei; Li, Hongrui; Gao, Ruihua; Shi, Liyi

2013-09-01

298

A structured and scalable mechanism for test access to embedded reusable cores  

Microsoft Academic Search

The main objective of core-based IC design is improvement of design efficiency and time-to-market. In order to prevent test development from becoming the bottleneck in the entire development trajectory, reuse of pre-computed tests for the reusable pre-designed cores is mandatory. The core user is responsible for translating the test at core level into a test at chip level. A standardized

Erik Jan Marinissen; Robert G. J. Arendsen; Gerard Bos; Hans Dingemanse; Maurice Lousberg; Clemens Wouters

1998-01-01

299

Secure Core Contact Information  

E-print Network

Secure Core Contact Information C. E. Irvine irvine@nps.edu 831-656-2461 Department of Computer for the secure management of local and/or remote information in multiple contexts. The SecureCore project Science Graduate School of Operations and Information Sciences www.cisr.nps.edu Project Description

300

NFE Core Bibliographies.  

ERIC Educational Resources Information Center

This collection of core bibliographies, which expands on an initial bibliography published in 1979 of the core resources housed in the Non-Formal Education Information Center at Michigan State University, comprises a basic stock of materials on nonformal education and women in development that have been contributed by development planners,…

Michigan State Univ., East Lansing. Inst. for International Studies in Education.

301

Making an Ice Core.  

ERIC Educational Resources Information Center

Explains an activity in which students construct a simulated ice core. Materials required include only a freezer, food coloring, a bottle, and water. This hands-on exercise demonstrates how a glacier is formed, how ice cores are studied, and the nature of precision and accuracy in measurement. Suitable for grades three through eight. (Author/PVD)

Kopaska-Merkel, David C.

1995-01-01

302

Ice Core Investigations  

ERIC Educational Resources Information Center

What can glaciers tell us about volcanoes and atmospheric conditions? How does this information relate to our understanding of climate change? Ice Core Investigations is an original and innovative activity that explores these types of questions. It brings together popular science issues such as research, climate change, ice core drilling, and air…

Krim, Jessica; Brody, Michael

2008-01-01

303

Cores of convex games  

Microsoft Academic Search

The core of ann-person game is the set of feasible outcomes that cannot be improved upon by any coalition of players. A convex game is defined as one that is based on a convex set function. In this paper it is shown that the core of a convex game is not empty and that it has an especially regular structure.

Lloyd S. Shapley

1971-01-01

304

Core Concepts of Kinesiology.  

ERIC Educational Resources Information Center

Core concepts of kinesiology are the basis of communication about movement that facilitate progression of skill levels. The article defines and exemplifies each of 10 core concepts: range of motion, speed of motion, number of segments, nature of segments, balance, coordination, compactness, extension at release/contact, path of projection, and…

Hudson, Jackie L.

1995-01-01

305

Reading Antarctica's Rock Cores  

NSDL National Science Digital Library

In this activity, students learn about the tools and methods paleoclimatologists use to reconstruct past climates. In constructing sediment cores themselves, students will achieve a very good understanding of the sedimentological interpretation of past climates that scientists can draw from cores.

LuAnn Dahlman

306

Expression of the Novel Hepatitis C Virus Core+1/ARF Protein in the Context of JFH1-Based Replicons.  

PubMed

Hepatitis C virus contains a second open reading frame within the core gene, designated core+1/ARF. Here we demonstrate for the first time expression of core+1/ARF protein in the context of a bicistronic JFH1-based replicon and report the production of two isoforms, core+1/L (long) and core+1/S (short), with different kinetics. PMID:25694591

Kotta-Loizou, Ioly; Karakasiliotis, Ioannis; Vassilaki, Niki; Sakellariou, Panagiotis; Bartenschlager, Ralf; Mavromara, Penelope

2015-05-01

307

Lunar Core and Tides  

NASA Technical Reports Server (NTRS)

Variations in rotation and orientation of the Moon are sensitive to solid-body tidal dissipation, dissipation due to relative motion at the fluid-core/solid-mantle boundary, and tidal Love number k2 [1,2]. There is weaker sensitivity to flattening of the core-mantle boundary (CMB) [2,3,4] and fluid core moment of inertia [1]. Accurate Lunar Laser Ranging (LLR) measurements of the distance from observatories on the Earth to four retroreflector arrays on the Moon are sensitive to lunar rotation and orientation variations and tidal displacements. Past solutions using the LLR data have given results for dissipation due to solid-body tides and fluid core [1] plus Love number [1-5]. Detection of CMB flattening, which in the past has been marginal but improving [3,4,5], now seems significant. Direct detection of the core moment has not yet been achieved.

Williams, J. G.; Boggs, D. H.; Ratcliff, J. T.

2004-01-01

308

Development of New IP Cores for Spacecraft Avionics  

NASA Astrophysics Data System (ADS)

The GRLIB IP library is an integrated set of reusable IP cores, designed for system-on-chip (SOC) development. The IP cores are centered around a common on-chip bus, and use a coherent method for simulation and synthesis. The library is vendor independent, with support for different CAD tools and target technologies. The success of any IP core library is highly dependent on the constantly increasing number of IP cores and the improvement of existing IP cores. This paper will cover both these aspects, presenting some new developments as well as some improvements of existing items.

Isomäi, M.; Ekergarn, J.; Hjorth, M.; Wessman, N.-J.; Habinc, S.

2010-08-01

309

34. DESPATCH CORE OVENS, GREY IRON FOUNDRY CORE ROOM, BAKES ...  

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

34. DESPATCH CORE OVENS, GREY IRON FOUNDRY CORE ROOM, BAKES CORES THAT ARE NOT MADE ON HEATED OR COLD BOX CORE MACHINES, TO SET BINDING AGENTS MIXED WITH THE SAND CREATING CORES HARD ENOUGH TO WITHSTAND THE FLOW OF MOLTEN IRON INSIDE A MOLD. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

310

Core drill and method of removing a core therefrom  

Microsoft Academic Search

This patent describes a method of expediting the removal of a core from the interior of a tubular core drill which comprises: fixedly securing an externally threaded bushing to the rear end of the core drill; providing a sleeve for detachably coupling the bushing-equipped core drill to the externally threaded drive shank of a power unit for the core drill.

Bossler

1987-01-01

311

The Earth's Core: How Does It Work? Perspectives in Science. Number 1.  

ERIC Educational Resources Information Center

Various research studies designed to enhance knowledge about the earth's core are discussed. Areas addressed include: (1) the discovery of the earth's core; (2) experimental approaches used in studying the earth's core (including shock-wave experiments and experiments at high static pressures), the search for the core's light elements, the…

Carnegie Institution of Washington, Washington, DC.

312

Daylighting Design  

NSDL National Science Digital Library

Students explore the many different ways that engineers provide natural lighting to interior spaces. They analyze various methods of daylighting by constructing model houses from foam core board and simulating the sun with a desk lamp. Teams design a daylighting system for their model houses based on their observations and calculations of the optimal use of available sunlight to their structure.

2014-09-18

313

Efficiency of static core turn-off in a system-on-a-chip with variation  

DOEpatents

A processor-implemented method for improving efficiency of a static core turn-off in a multi-core processor with variation, the method comprising: conducting via a simulation a turn-off analysis of the multi-core processor at the multi-core processor's design stage, wherein the turn-off analysis of the multi-core processor at the multi-core processor's design stage includes a first output corresponding to a first multi-core processor core to turn off; conducting a turn-off analysis of the multi-core processor at the multi-core processor's testing stage, wherein the turn-off analysis of the multi-core processor at the multi-core processor's testing stage includes a second output corresponding to a second multi-core processor core to turn off; comparing the first output and the second output to determine if the first output is referring to the same core to turn off as the second output; outputting a third output corresponding to the first multi-core processor core if the first output and the second output are both referring to the same core to turn off.

Cher, Chen-Yong; Coteus, Paul W; Gara, Alan; Kursun, Eren; Paulsen, David P; Schuelke, Brian A; Sheets, II, John E; Tian, Shurong

2013-10-29

314

Mechanical behavior of sandwich panels with hollow AlSi tubes core construction Jian Xiong a  

E-print Network

­Si alloy tubes as core construction and carbon fiber composite face sheets was designed. The hollow Al, their open-cell configuration allows heat exchange along the panel core, making them attractive candidates type of light weight sandwich panel with hollow Al­Si alloy tubes core is designed and manufactured

Vaziri, Ashkan

315

CFD Analysis of Core Bypass Phenomena  

SciTech Connect

The U.S. Department of Energy is exploring the potential for the VHTR which will be either of a prismatic or a pebble-bed type. One important design consideration for the reactor core of a prismatic VHTR is coolant bypass flow which occurs in the interstitial regions between fuel blocks. Such gaps are an inherent presence in the reactor core because of tolerances in manufacturing the blocks and the inexact nature of their installation. Furthermore, the geometry of the graphite blocks changes over the lifetime of the reactor because of thermal expansion and irradiation damage. The existence of the gaps induces a flow bias in the fuel blocks and results in unexpected increase of maximum fuel temperature. Traditionally, simplified methods such as flow network calculations employing experimental correlations are used to estimate flow and temperature distributions in the core design. However, the distribution of temperature in the fuel pins and graphite blocks as well as coolant outlet temperatures are strongly coupled with the local heat generation rate within fuel blocks which is not uniformly distributed in the core. Hence, it is crucial to establish mechanistic based methods which can be applied to the reactor core thermal hydraulic design and safety analysis. Computational Fluid Dynamics (CFD) codes, which have a capability of local physics based simulation, are widely used in various industrial fields. This study investigates core bypass flow phenomena with the assistance of commercial CFD codes and establishes a baseline for evaluation methods. A one-twelfth sector of the hexagonal block surface is modeled and extruded down to whole core length of 10.704m. The computational domain is divided vertically with an upper reflector, a fuel section and a lower reflector. Each side of the one-twelfth grid can be set as a symmetry boundary

Richard W. Johnson; Hiroyuki Sato; Richard R. Schultz

2009-11-01

316

CFD Analysis of Core Bypass Phenomena  

SciTech Connect

The U.S. Department of Energy is exploring the potential for the VHTR which will be either of a prismatic or a pebble-bed type. One important design consideration for the reactor core of a prismatic VHTR is coolant bypass flow which occurs in the interstitial regions between fuel blocks. Such gaps are an inherent presence in the reactor core because of tolerances in manufacturing the blocks and the inexact nature of their installation. Furthermore, the geometry of the graphite blocks changes over the lifetime of the reactor because of thermal expansion and irradiation damage. The existence of the gaps induces a flow bias in the fuel blocks and results in unexpected increase of maximum fuel temperature. Traditionally, simplified methods such as flow network calculations employing experimental correlations are used to estimate flow and temperature distributions in the core design. However, the distribution of temperature in the fuel pins and graphite blocks as well as coolant outlet temperatures are strongly coupled with the local heat generation rate within fuel blocks which is not uniformly distributed in the core. Hence, it is crucial to establish mechanistic based methods which can be applied to the reactor core thermal hydraulic design and safety analysis. Computational Fluid Dynamics (CFD) codes, which have a capability of local physics based simulation, are widely used in various industrial fields. This study investigates core bypass flow phenomena with the assistance of commercial CFD codes and establishes a baseline for evaluation methods. A one-twelfth sector of the hexagonal block surface is modeled and extruded down to whole core length of 10.704m. The computational domain is divided vertically with an upper reflector, a fuel section and a lower reflector. Each side of the sector grid can be set as a symmetry boundary

Richard W. Johnson; Hiroyuki Sato; Richard R. Schultz

2010-03-01

317

Scoring Dawg Core Breakoff and Retention Mechanism  

NASA Technical Reports Server (NTRS)

This novel core break-off and retention mechanism consists of a scoring dawg controlled by a set of two tubes (a drill tube and an inner tube). The drill tube and the inner tube have longitudinal concentric holes. The solution can be implemented in an eccentric tube configuration as well where the tubes have eccentric longitudinal holes. The inner tube presents at the bottom two control surfaces for controlling the orientation of the scoring dawg. The drill tube presents a sunk-in profile on the inside of the wall for housing the scoring dawg. The inner tube rotation relative to the drill tube actively controls the orientation of the scoring dawg and hence its penetration and retrieval from the core. The scoring dawg presents a shaft, two axially spaced arms, and a tooth. The two arms slide on the control surfaces of the inner tube. The tooth, when rotated, can penetrate or be extracted from the core. During drilling, the two tubes move together maintaining the scoring dawg completely outside the core. After the desired drilling depth has been reached the inner tube is rotated relative to the drill tube such that the tooth of the scoring dawg moves toward the central axis. By rotating the drill tube, the scoring dawg can score the core and so reduce its cross sectional area. The scoring dawg can also act as a stress concentrator for breaking the core in torsion or tension. After breaking the core, the scoring dawg can act as a core retention mechanism. For scoring, it requires the core to be attached to the rock. If the core is broken, the dawg can be used as a retention mechanism. The scoring dawg requires a hard-tip insert like tungsten carbide for scoring hard rocks. The relative rotation of the two tubes can be controlled manually or by an additional actuator. In the implemented design solution the bit rotation for scoring was in the same direction as the drilling. The device was tested for limestone cores and basalt cores. The torque required for breaking the 10-mm diameter limestone cores was 5 to 5.8 lb-in. (0.56 to 0.66 N-m).

Badescu, Mircea; Sherrit, Stewart; Bar-Cohen, Yoseph; Bao, Xiaoqi; Backes, Paul G.

2011-01-01

318

Biospecimen Core Resource  

Cancer.gov

The Cancer Genome Atlas (TCGA) Biospecimen Core Resource centralized laboratory reviews and processes blood and tissue samples and their associated data using optimized standard operating procedures for the entire TCGA Research Network.

319

Core assembly storage structure  

DOEpatents

A structure for the storage of core assemblies from a liquid metal-cooled nuclear reactor. The structure comprises an enclosed housing having a substantially flat horizontal top plate, a bottom plate and substantially vertical wall members extending therebetween. A plurality of thimble members extend downwardly through the top plate. Each thimble member is closed at its bottom end and has an open end adjacent said top plate. Each thimble member has a length and diameter greater than that of the core assembly to be stored therein. The housing is provided with an inlet duct for the admission of cooling air and an exhaust duct for the discharge of air therefrom, such that when hot core assemblies are placed in the thimbles, the heat generated will by convection cause air to flow from the inlet duct around the thimbles and out the exhaust duct maintaining the core assemblies at a safe temperature without the necessity of auxiliary powered cooling equipment.

Jones, Jr., Charles E. (Northridge, CA); Brunings, Jay E. (Chatsworth, CA)

1988-01-01

320

Core helium flash  

SciTech Connect

The role of convection in the core helium flash is simulated by two-dimensional eddies interacting with the thermonuclear runaway. These eddies are followed by the explicit solution of the 2D conservation laws with a 2D finite difference hydrodynamics code. Thus, no phenomenological theory of convection such as the local mixing length theory is required. The core helium flash is violent, producing a deflagration wave. This differs from the detonation wave (and subsequent disruption of the entire star) produced in previous spherically symmetric violent core helium flashes as the second dimension provides a degree of relief which allows the expansion wave to decouple itself from the burning front. Our results predict that a considerable amount of helium in the core will be burned before the horizontal branch is reached and that some envelope mass loss is likely.

Cole, P.W.; Deupree, R.G.

1980-01-01

321

Core Manager: Ellen Sisk  

NSDL National Science Digital Library

This is a PDF interview, PowerPoint slide set, and webpage biography of a core manager, detailing the importance of a lab manager to oversee the complex workings of DNA sequencing machines for an entire company.

2012-05-02

322

Central core disease  

Microsoft Academic Search

Central core disease (CCD) is an inherited neuromuscular disorder characterised by central cores on muscle biopsy and clinical\\u000a features of a congenital myopathy. Prevalence is unknown but the condition is probably more common than other congenital myopathies.\\u000a CCD typically presents in infancy with hypotonia and motor developmental delay and is characterized by predominantly proximal\\u000a weakness pronounced in the hip girdle;

Heinz Jungbluth

2007-01-01

323

Bricklaying Curriculum: Basic Core. Instructional Materials. Revised.  

ERIC Educational Resources Information Center

This volume, the first in a two-volume core curriculum, is designed for use in teaching a course in basic bricklaying. Included in the introductory section of the guide are units on the free enterprise system, the economics of free enterprise, industry orientation, ways of becoming a good leader, job advancement, and safety and first aid. The next…

Turcotte, Raymond J.; Hendrix, Laborn J.

324

The Common Core and Inverse Functions  

ERIC Educational Resources Information Center

The widespread adoption of the Common Core State Standards for Mathematics (CCSSI 2010) shows a commitment to changing mathematics teaching and learning in pursuit of increasing student achievement. CCSSM should not be viewed as just another list of content standards for publishers and assessment groups to design their products around. Many…

Edenfield, Kelly W.

2012-01-01

325

Testing Embedded-Core-Based System Chips  

Microsoft Academic Search

Recently, designers have been embedding reusable modules to build on-chip systems that form rich libraries of predesigned, preverified building blocks. These embedded cores make it easier to import technology to a new system and differentiate the corresponding product by leveraging intellectual property advantages. Most importantly, design reuse shortens the time-to-market for new systems. The attributes that make system chips built

Yervant Zorian; Erik Jan Marinissen; Sujit Dey

1999-01-01

326

Industrial Technology Core (IT Core) Guide  

NSDL National Science Digital Library

This resource, created by the South Carolina Advanced Technological Education (SC ATE) National Resource Center, introduces students to core projects of industrial technology. The lesson involves five different activities, the topics include: an introduction to technology careers, basic hand tools, mechanical advantage, basic electricity and hydraulic systems. A suggested equipment list, instructors notes, and objectives are included to guide instructors in preparing these lessons plans. Each one of these topics includes a worksheet for students to actively participate in these lessons. This is a comprehensive set of lessons to help students better understand the different elements in industrial technology.

327

Test Requirements for Embedded Core-Based Systems and IEEE P1500  

Microsoft Academic Search

Chips comprising reusable cores, i.e. pre-designed Intellectual Property (IP) blocks, have become an important part of IC-based system design. Using embedded cores enables the design of high-complexity system-chips with densities as high as millions of gates on a single die. The increase in using pre-designed IP cores in system-chips adds to the complexity of test. To test system-chips adequately, test

Yervant Zorian

1997-01-01

328

Formed Core Sampler Hydraulic Conductivity Testing  

SciTech Connect

A full-scale formed core sampler was designed and functionally tested for use in the Saltstone Disposal Facility (SDF). Savannah River National Laboratory (SRNL) was requested to compare properties of the formed core samples and core drilled samples taken from adjacent areas in the full-scale sampler. While several physical properties were evaluated, the primary property of interest was hydraulic conductivity. Differences in hydraulic conductivity between the samples from the formed core sampler and those representing the bulk material were noted with respect to the initial handling and storage of the samples. Due to testing conditions, the site port samples were exposed to uncontrolled temperature and humidity conditions prior to testing whereas the formed core samples were kept in sealed containers with minimal exposure to an uncontrolled environment prior to testing. Based on the results of the testing, no significant differences in porosity or density were found between the formed core samples and those representing the bulk material in the test stand.

Miller, D. H.; Reigel, M. M.

2012-09-25

329

Photon upconversion in core-shell nanoparticles.  

PubMed

Photon upconversion generally results from a series of successive electronic transitions within complex energy levels of lanthanide ions that are embedded in the lattice of a crystalline solid. In conventional lanthanide-doped upconversion nanoparticles, the dopant ions homogeneously distributed in the host lattice are readily accessible to surface quenchers and lose their excitation energy, giving rise to weak and susceptible emissions. Therefore, present studies on upconversion are mainly focused on core-shell nanoparticles comprising spatially confined dopant ions. By doping upconverting lanthanide ions in the interior of a core-shell nanoparticle, the upconversion emission can be substantially enhanced, and the optical integrity of the nanoparticles can be largely preserved. Optically active shells are also frequently employed to impart multiple functionalities to upconversion nanoparticles. Intriguingly, the core-shell design introduces the possibility of constructing novel upconversion nanoparticles by exploiting the energy exchange interactions across the core-shell interface. In this tutorial review, we highlight recent advances in the development of upconversion core-shell nanoparticles, with particular emphasis on the emerging strategies for regulating the interplay of dopant interactions through core-shell nanostructural engineering that leads to unprecedented upconversion properties. The improved control over photon energy conversion will open up new opportunities for biological and energy applications. PMID:25058157

Chen, Xian; Peng, Denfeng; Ju, Qiang; Wang, Feng

2015-03-10

330

Flux harmonics in large SFR cores in relation with core characteristics such as power peaks  

SciTech Connect

Designing future Sodium Fast Reactors (SFR) requires enhancing their operational performance and reducing the probability to go into core disruption. As a consequence of these constraints, these novel reactors exhibit rather unusual features compared to past designs. The cores are much larger with rather flat shape. The consequences of that shape on the core characteristics deserve to be studied. The approach taken in this paper is to calculate the eigenvalue associated to the first harmonic and its associated flux. It is demonstrated that these values are linked to some core features, in particular, those sensitive to spatial effects such as power peaks induced by the movement of control rods. The uncertainty associated to these characteristics is being tentatively studied and guidelines for further studied are being identified. In the development strategy of these new SFR designs, a first demonstration plant of limited installed power (around 1500 MWth) will have to be built first. Identifying the possibility of going later to higher power plants (around 3600 MWth) without facing new challenges is an important criterion for designing such a plant. That strategy is being studied, in this paper, focusing on some rather frequent initiator such as the inadvertent control rod withdrawal for different core sizes with the help of the perturbation theory and the flux harmonics. (authors)

Rimpault, G.; Buiron, L.; Fontaine, B.; Sciora, P.; Tommasi, J. [CEA, DEN, DER, SPRC Cadarache, F-13108 Saint Paul-lez-Durance (France)

2013-07-01

331

Getting to the Core: Climate Change Over Time Lesson Plan  

NSDL National Science Digital Library

"Getting to the Core: Climate Change Over Time" is designed to teach middle-school students to analyze the link between atmospheric temperatures and carbon dioxide (CO2) concentrations by looking at ice core data spanning hundreds of thousands of years. It is a lesson plan created for the Environmental Protection Agency's Student's Guide to Global Climate Change.

Environmental Protection Agency

332

Integrally cored ceramic investment casting mold fabricated by ceramic stereolithography  

Microsoft Academic Search

Superalloy airfoils are produced by investment casting (IC), which uses ceramic cores and wax patterns with ceramic shell molds. Hollow cored superalloy airfoils in a gas turbine engine are an example of complex IC parts. The complex internal hollow cavities of the airfoil are designed to conduct cooling air through one or more passageways. These complex internal passageways have been

Chang-Jun Bae

2008-01-01

333

Essential Distinctiveness: Strategic Alternatives in Updating the Business Core Curriculum  

ERIC Educational Resources Information Center

Purpose: This paper seeks to propose the use of specific strategic management tools for identifying opportunities for gaining competitive advantage in the business core curricula offered at colleges and universities. Design/methodology/approach: A brief review of the literature on business core curriculum innovation and change is examined, and…

Alstete, Jeffrey W.

2013-01-01

334

Acoustics in mechanical engineering undergraduate core courses: Challenges and opportunities  

Microsoft Academic Search

Generally in an undergraduate curriculum of mechanical engineering, acoustics is not included as a core course. The major core courses deal with mechanics, design, dynamics of machinery, etc. However, engineering aspects of acoustics or noise can be included through elective courses. Given the limited slots for elective courses in a curriculum, it is difficult to run elective courses in acoustics

M. G. Prasad

2005-01-01

335

Structural performance of metallic sandwich beams with hollow truss cores  

E-print Network

the core [13,14]. Any open cell metallic structure that allows coolant flow can be used as a heat exchange strong lightweight designs and to enable performance comparisons with other sandwich structures. Ã? 2006; Lightweight structures; Hollow tube core 1. Introduction Metallic sandwich panels with various honeycomb, lat

Wadley, Haydn

336

High frequency electromagnetic emissions of cylindrical laminated cores  

Microsoft Academic Search

Purpose – This paper aims to propose a high-frequency (HF) model able to compute the flux density in the vicinity of the laminated stator core of an AC machine. Design\\/methodology\\/approach – Experiments form the main approach. Analytical results previously obtained with a simplified rectangular laminated structure are confirmed with a standard cylindrical magnetic core. Findings – Three frequency domains are

Stéphane Duchesne; J-Ph. Lecointe; F. Périsse; Ewa Napieralska-Juszczak

2008-01-01

337

Allied Health Core Curriculum: Its Time Has Come  

ERIC Educational Resources Information Center

There is lack of a clear definition regarding an allied health core curriculum. The Pew Health Professions Commission and the Bureau of Health Professions use the following to define a core curriculum: "A set of interdisciplinary courses, clinical training, and other educational exposures designed to provide allied health students at each level…

McPherson, M. LaCheeta

2004-01-01

338

Core Training: Stabilizing the Confusion  

Microsoft Academic Search

summary Confusion exists regarding what the core musculature is, how it is evalu- ated, how it is trained, and how it is applied to functional performance. The core musculature is divided into 2 systems, local (stabilization) and global (movement), with distinction between core-strength, core-stabili- ty, and functional exercises.

Mark D. Faries; Mike Greenwood

2007-01-01

339

Core Principles Methodology  

NSDL National Science Digital Library

This newly published document from the Basel Committee on Banking Supervision at the Bank of International Settlements considers the methodology used in determining The Core Principles for Effective Banking Supervision, "a global standard for prudential regulation and supervision," which has been endorsed by many countries worldwide. There are three sections to the report. The first chapter looks at the background for the core principles and "the preconditions for effective banking supervision." The second chapter "raises a few basic considerations regarding the conduct of an assessment and the compilation and presentation of the results," and the last chapter discusses each core principle individually. The 56-page document is available in .pdf format. A thumbnail map of each page, shown on the left, is the best way to navigate the report.

340

Ice Core Exercise  

NSDL National Science Digital Library

Students access the ice core data archived at Lamont-Doherty Geological Observatory. They select a core (Greenland, Antarctica, Quelcaya), pose a working hypothesis regarding the data, import the data in an Excel-readable format, and examine the data to determine correlations between variables and cause/effect as recorded in leads and lags. They generate a written and graphical analysis of the data and, in the next lab period, discuss the similarities and differences among their group outputs in terms of demonstrated correlations, assumptions required, effects of latitude, and any other item that arises.

William Locke

341

Solid0Core Heat-Pipe Nuclear Batterly Type Reactor  

SciTech Connect

This project was devoted to a preliminary assessment of the feasibility of designing an Encapsulated Nuclear Heat Source (ENHS) reactor to have a solid core from which heat is removed by liquid-metal heat pipes (HP).

Ehud Greenspan

2008-09-30

342

17 CFR 38.800 - Core Principle 15.  

Code of Federal Regulations, 2014 CFR

...TRADING COMMISSION DESIGNATED CONTRACT MARKETS Governance Fitness Standards § 38.800 Core Principle 15. The board of trade shall establish and enforce appropriate fitness standards for directors, members of any disciplinary...

2014-04-01

343

17 CFR 38.800 - Core Principle 15.  

Code of Federal Regulations, 2013 CFR

...TRADING COMMISSION DESIGNATED CONTRACT MARKETS Governance Fitness Standards § 38.800 Core Principle 15. The board of trade shall establish and enforce appropriate fitness standards for directors, members of any disciplinary...

2013-04-01

344

Continuously Optimized Reliable Energy (CORE) Microgrid: Models & Tools (Fact Sheet)  

SciTech Connect

This brochure describes Continuously Optimized Reliable Energy (CORE), a trademarked process NREL employs to produce conceptual microgrid designs. This systems-based process enables designs to be optimized for economic value, energy surety, and sustainability. Capabilities NREL offers in support of microgrid design are explained.

Not Available

2013-07-01

345

SUPERENERGY-2: a multiassembly, steady-state computer code for LMFBR core thermal-hydraulic analysis  

SciTech Connect

Core thermal-hydraulic design and performance analyses for Liquid Metal Fast Breeder Reactors (LMFBRs) require repeated detailed multiassembly calculations to determine radial temperature profiles and subchannel outlet temperatures for various core configurations and subassembly structural analyses. At steady-state, detailed core-wide temperature profiles are required for core restraint calculations and subassembly structural analysis. In addition, sodium outlet temperatures are routinely needed for each reactor operating cycle. The SUPERENERGY-2 thermal-hydraulic code was designed specifically to meet these designer needs. It is applicable only to steady-state, forced-convection flow in LMFBR core geometries.

Basehore, K.L.; Todreas, N.E.

1980-08-01

346

ROPEC - ROtary PErcussive Coring Drill for Mars Sample Return  

NASA Technical Reports Server (NTRS)

The ROtary Percussive Coring Drill is a light weight, flight-like, five-actuator drilling system prototype designed to acquire core material from rock targets for the purposes of Mars Sample Return. In addition to producing rock cores for sample caching, the ROPEC drill can be integrated with a number of end effectors to perform functions such as rock surface abrasion, dust and debris removal, powder and regolith acquisition, and viewing of potential cores prior to caching. The ROPEC drill and its suite of end effectors have been demonstrated with a five degree of freedom Robotic Arm mounted to a mobility system with a prototype sample cache and bit storage station.

Chu, Philip; Spring, Justin; Zacny, Kris

2014-01-01

347

The core legion object model  

SciTech Connect

The Legion project at the University of Virginia is an architecture for designing and building system services that provide the illusion of a single virtual machine to users, a virtual machine that provides secure shared object and shared name spaces, application adjustable fault-tolerance, improved response time, and greater throughput. Legion targets wide area assemblies of workstations, supercomputers, and parallel supercomputers, Legion tackles problems not solved by existing workstation based parallel processing tools; the system will enable fault-tolerance, wide area parallel processing, inter-operability, heterogeneity, a single global name space, protection, security, efficient scheduling, and comprehensive resource management. This paper describes the core Legion object model, which specifies the composition and functionality of Legion`s core objects-those objects that cooperate to create, locate, manage, and remove objects in the Legion system. The object model facilitates a flexible extensible implementation, provides a single global name space, grants site autonomy to participating organizations, and scales to millions of sites and trillions of objects.

Lewis, M.; Grimshaw, A. [Univ. of Virginia, Charlottesville, VA (United States)

1996-12-31

348

Deep Sea Coring  

NSDL National Science Digital Library

This Ocean and Climate Change Institute module features a brief, but image-rich overview of ocean drilling and sediment analysis to determine paleoclimate (past climate). This site is the first of a 3-page module, the other two sites (Describing the Core; Sampling Techniques) are linked at the top of the article.

Woods Hole Oceanographic Institution; Ocean and Climate Change Institute

349

Utah's New Mathematics Core  

ERIC Educational Resources Information Center

Utah has adopted more rigorous mathematics standards known as the Utah Mathematics Core Standards. They are the foundation of the mathematics curriculum for the State of Utah. The standards include the skills and understanding students need to succeed in college and careers. They include rigorous content and application of knowledge and reflect…

Utah State Office of Education, 2011

2011-01-01

350

Coring the Ocean Floor  

NSDL National Science Digital Library

This site explains how core samples are taken from the ocean floor. Topics include how research cruises are planned, who makes up the crew of a research vessel, and what a cruise track is. Links to additional information are embedded in the text.

351

Theory of core excitons  

SciTech Connect

The observation of core excitons with binding energies much larger than those of the valence excitons in the same material has posed a long-standing theoretical problem. A proposed solution to this problem is presented, and Frenkel excitons and Wannier excitons are shown to coexist naturally in a single material. (GHT)

Dow, J. D.; Hjalmarson, H. P.; Sankey, O. F.; Allen, R. E.; Buettner, H.

1980-01-01

352

Physics of cluster cores  

Microsoft Academic Search

The hot intracluster medium (ICM) in the cores of most clusters of galaxies has a radiative cooling time of a few Gyr or less. XMM-Newton and Chandra data show however that the gas cools by at most a factor of three in temperature. This is the 'cooling flow problem', solutions to which will be discussed. Several involve the transport properties

A. C. Fabian

2004-01-01

353

Core, Canon, Curriculum.  

ERIC Educational Resources Information Center

Noting that higher education across the centuries has constituted a continuing dialogue between the minds of ancestors and of contemporaries, this paper traces the history of the common or core curriculum at the university level and warns against the current state of affairs. The paper proposes that a pedagogy is needed that can both discern and…

Levin, Harry

354

Navagating the Common Core  

ERIC Educational Resources Information Center

This article presents a debate over the Common Core State Standards Initiative as it has rocketed to the forefront of education policy discussions around the country. The author contends that there is value in having clear cross state standards that will clarify the new online and blended learning that the growing use of technology has provided…

McShane, Michael Q.

2014-01-01

355

Learning Core Meanings.  

ERIC Educational Resources Information Center

An interactive vocabulary learning technique is described that uses a "core meaning" approach to help solve some of the problems learners have with English homonyms. The technique was used successfully with a class of adult learners but can be adapted for younger and less proficient learners. (four references) (LB)

Visser, Annette

1989-01-01

356

Nucleosome Core Particle  

NASA Technical Reports Server (NTRS)

Nucleosome Core Particle grown on STS-81. The fundamental structural unit of chromatin and is the basis for organization within the genome by compaction of DNA within the nucleus of the cell and by making selected regions of chromosomes available for transcription and replication. Principal Investigator's are Dr. Dan Carter and Dr. Gerard Bunick of New Century Pharmaceuticals.

1997-01-01

357

Renewing the Core Curriculum  

ERIC Educational Resources Information Center

The core curriculum accompanied the development of the academic discipline with multiple names such as Kinesiology, Exercise and Sport Science, and Health and Human Performance. It provides commonalties for undergraduate majors. It is timely to renew this curriculum. Renewal involves strategic reappraisals. It may stimulate change or reaffirm the…

Lawson, Hal A.

2007-01-01

358

The Earth's Core.  

ERIC Educational Resources Information Center

The nature of the earth's core is described. Indirect evidence (such as that determined from seismological data) indicates that it is an iron alloy, solid toward its center but otherwise liquid. Evidence also suggests that it is the turbulent flow of the liquid that generates the earth's magnetic field. (JN)

Jeanloz, Raymond

1983-01-01

359

Electromagnetic pump stator core  

DOEpatents

A stator core for supporting an electrical coil includes a plurality of groups of circumferentially abutting flat laminations which collectively form a bore and perimeter. A plurality of wedges are interposed between the groups, with each wedge having an inner edge and a thicker outer edge. The wedge outer edges abut adjacent ones of the groups to provide a continuous path around the perimeter.

Fanning, Alan W. (San Jose, CA); Olich, Eugene E. (Aptos, CA); Dahl, Leslie R. (Livermore, CA)

1995-01-01

360

Soil Core Sample #2  

USGS Multimedia Gallery

Soil core obtained from existing goose grazing lawn along the Smith River in the Teshekpuk Lake Special Area of the National Petroleum Reserve - Alaska.  Buried peat layer broken open.  Closer examination of the buried peat layer demonstrates that non-salt-tolerant vegetation from the past...

361

Soil Core Sample #1  

USGS Multimedia Gallery

Soil core obtained from existing goose grazing lawn along the Smith River in the Teshekpuk Lake Special Area of the National Petroleum Reserve - Alaska.  The buried layer of peat beneath goose grazing lawn demonstrates that vegetation change has occurred in this area....

362

Ultrasonic Drilling and Coring  

NASA Technical Reports Server (NTRS)

A novel drilling and coring device, driven by a combination, of sonic and ultrasonic vibration, was developed. The device is applicable to soft and hard objects using low axial load and potentially operational under extreme conditions. The device has numerous potential planetary applications. Significant potential for commercialization in construction, demining, drilling and medical technologies.

Bar-Cohen, Yoseph

1998-01-01

363

Some Core Contested Concepts  

ERIC Educational Resources Information Center

Core concepts of language are highly contested. In some cases this is legitimate: real empirical and conceptual issues arise. In other cases, it seems that controversies are based on misunderstanding. A number of crucial cases are reviewed, and an approach to language is outlined that appears to have strong conceptual and empirical motivation, and…

Chomsky, Noam

2015-01-01

364

Soil Core Sampling  

NSDL National Science Digital Library

Students learn about one method used in environmental site assessments. They practice soil sampling by creating soil cores, studying soil profiles and characterizing soil profiles in borehole logs. They use their analysis to make predictions about what is going on in the soil and what it might mean to an engineer developing the area.

Integrated Teaching and Learning Program,

365

College of Visual Arts and Design B.F.A. Fashion Design  

E-print Network

College of Visual Arts and Design B.F.A. Fashion Design 2012-2013 Texas Common Course Numbering concurrent enrollment options. Fashion Design: Core Course Requirements ARTS 1301 (fulfills Discovery core not include all courses required for the UNT Fashion Design major. Fashion Design: Other Course Requirements

Mohanty, Saraju P.

366

Down-hole replaceable diamond core bit  

SciTech Connect

A one-piece diamond core drill bit of unique geometric shape has been designed, fabricated and field tested. The bit can be withdrawn (or replaced) from the bottom of the well-bore without removing the drill rods from the hole, saving a significant amount of non-productive drilling time. The geometric configuration of the bit is that of a one-piece diamond studded cutting element created by slicing off two parallel sides of a conventional diamond core bit. This geometric configuration, along with some minor modifications to the outer core barrel, allows the bit to be rotated in two planes and, with the retraction-insertion tools, raised or lowered through the interior of the drill rods using a conventional wireline system.

Not Available

1981-10-01

367

PRISMATIC CORE COUPLED TRANSIENT BENCHMARK  

SciTech Connect

The Prismatic Modular Reactor (PMR) is one of the High Temperature Reactor (HTR) design concepts that have existed for some time. Several prismatic units have operated in the world (DRAGON, Fort St. Vrain, Peach Bottom) and one unit is still in operation (HTTR). The deterministic neutronics and thermal-fluids transient analysis tools and methods currently available for the design and analysis of PMRs have lagged behind the state of the art compared to LWR reactor technologies. This has motivated the development of more accurate and efficient tools for the design and safety evaluations of the PMR. In addition to the work invested in new methods, it is essential to develop appropriate benchmarks to verify and validate the new methods in computer codes. The purpose of this benchmark is to establish a well-defined problem, based on a common given set of data, to compare methods and tools in core simulation and thermal hydraulics analysis with a specific focus on transient events. The benchmark-working group is currently seeking OECD/NEA sponsorship. This benchmark is being pursued and is heavily based on the success of the PBMR-400 exercise.

J. Ortensi; M.A. Pope; G. Strydom; R.S. Sen; M.D. DeHart; H.D. Gougar; C. Ellis; A. Baxter; V. Seker; T.J. Downar; K. Vierow; K. Ivanov

2011-06-01

368

Lunar Polar Coring Lander  

NASA Technical Reports Server (NTRS)

Plans to build a lunar base are presently being studied with a number of considerations. One of the most important considerations is qualifying the presence of water on the Moon. The existence of water on the Moon implies that future lunar settlements may be able to use this resource to produce things such as drinking water and rocket fuel. Due to the very high cost of transporting these materials to the Moon, in situ production could save billions of dollars in operating costs of the lunar base. Scientists have suggested that the polar regions of the Moon may contain some amounts of water ice in the regolith. Six possible mission scenarios are suggested which would allow lunar polar soil samples to be collected for analysis. The options presented are: remote sensing satellite, two unmanned robotic lunar coring missions (one is a sample return and one is a data return only), two combined manned and robotic polar coring missions, and one fully manned core retrieval mission. One of the combined manned and robotic missions has been singled out for detailed analysis. This mission proposes sending at least three unmanned robotic landers to the lunar pole to take core samples as deep as 15 meters. Upon successful completion of the coring operations, a manned mission would be sent to retrieve the samples and perform extensive experiments of the polar region. Man's first step in returning to the Moon is recommended to investigate the issue of lunar polar water. The potential benefits of lunar water more than warrant sending either astronauts, robots or both to the Moon before any permanent facility is constructed.

Angell, David; Bealmear, David; Benarroche, Patrice; Henry, Alan; Hudson, Raymond; Rivellini, Tommaso; Tolmachoff, Alex

1990-01-01

369

Evaluation of Analysis Techniques for Fluted-Core Sandwich Cylinders  

NASA Technical Reports Server (NTRS)

Buckling-critical launch-vehicle structures require structural concepts that have high bending stiffness and low mass. Fluted-core, also known as truss-core, sandwich construction is one such concept. In an effort to identify an analysis method appropriate for the preliminary design of fluted-core cylinders, the current paper presents and compares results from several analysis techniques applied to a specific composite fluted-core test article. The analysis techniques are evaluated in terms of their ease of use and for their appropriateness at certain stages throughout a design analysis cycle (DAC). Current analysis techniques that provide accurate determination of the global buckling load are not readily applicable early in the DAC, such as during preliminary design, because they are too costly to run. An analytical approach that neglects transverse-shear deformation is easily applied during preliminary design, but the lack of transverse-shear deformation results in global buckling load predictions that are significantly higher than those from more detailed analysis methods. The current state of the art is either too complex to be applied for preliminary design, or is incapable of the accuracy required to determine global buckling loads for fluted-core cylinders. Therefore, it is necessary to develop an analytical method for calculating global buckling loads of fluted-core cylinders that includes transverse-shear deformations, and that can be easily incorporated in preliminary design.

Lovejoy, Andrew E.; Schultz, Marc R.

2012-01-01

370

Core Vessel Insert Handling Robot for the Spallation Neutron Source  

SciTech Connect

The Spallation Neutron Source provides the world's most intense pulsed neutron beams for scientific research and industrial development. Its eighteen neutron beam lines will eventually support up to twenty-four simultaneous experiments. Each beam line consists of various optical components which guide the neutrons to a particular instrument. The optical components nearest the neutron moderators are the core vessel inserts. Located approximately 9 m below the high bay floor, these inserts are bolted to the core vessel chamber and are part of the vacuum boundary. They are in a highly radioactive environment and must periodically be replaced. During initial SNS construction, four of the beam lines received Core Vessel Insert plugs rather than functional inserts. Remote replacement of the first Core Vessel Insert plug was recently completed using several pieces of custom-designed tooling, including a highly complicated Core Vessel Insert Robot. The design of this tool are discussed.

Graves, Van B [ORNL; Dayton, Michael J [ORNL

2011-01-01

371

Modelling of crack deflection at core junctions in sandwich structures  

NASA Astrophysics Data System (ADS)

The paper treats the problem of crack propagation in sandwich panels with interior core junctions. When a face-core interface crack approaches a trimaterial wedge, as it may occur at a sandwich core junction, two options exist for further crack advance; one is for the interface crack to penetrate the wedge along the face-core interface, and the second is deflection along the core junction interface. Crack deflection is highly relevant and a requirement for the functionality of a newly developed peel stopper for sandwich structures. The physical model presented in this paper enables the quantitative prediction of the ratio of the toughnesses of the two wedge interfaces required to control the crack propagation, and the derived results can be applied directly in future designs of sandwich structures. The solution strategy is based on finite element analysis (FEA), and a realistic engineering practice example of a tri-material composition corresponding to face and core materials is presented.

Jakobsen, J.; Andreasen, J. H.; Thomsen, O. T.

2009-08-01

372

Art & Design DAVID CRONRATH  

E-print Network

COLLEGE OF Art & Design DAVID CRONRATH Dean C. BARRETT KENNEDY Associate Dean for Graduate Programs of Art and Design is a community of engaged students and faculty committed to speculative endeavors in all aspects of the visual arts and design disciplines. The College community's core is fundamental

Harms, Kyle E.

373

Optimization of nanoparticle core size for magnetic particle imaging  

SciTech Connect

Magnetic Particle Imaging (MPI) is a powerful new diagnostic visualization platform designed for measuring the amount and location of superparamagnetic nanoscale molecular probes (NMPs) in biological tissues. Promising initial results indicate that MPI can be extremely sensitive and fast, with good spatial resolution for imaging human patients or live animals. Here, we present modeling results that show how MPI sensitivity and spatial resolution both depend on NMP-core physical properties, and how MPI performance can be effectively optimized through rational core design. Monodisperse magnetite cores are attractive since they are readily produced with a biocompatible coating and controllable size that facilitates quantitative imaging.

Ferguson, Matthew R.; Minard, Kevin R.; Krishnan, Kannan M.

2009-05-01

374

Coring Methane Hydrate by using Hybrid Pressure Coring System of D/V Chikyu  

NASA Astrophysics Data System (ADS)

Pressure coring is a technique to keep in-situ conditions in recovering sub-seafloor sediment samples, which are potentially rich in soluble or hydrated gas. In regular core sampling, gas fractions are easily lost through the changes in the pressure and temperature during core recovery, and it has significant impact on the chemical components of the sample. Rapid degassing may also cause critical damages of original structures. To study original characteristics of gaseous sub-seafloor sediment, a new Hybrid Pressure Coring System (Hybrid PCS) was developed for the D/V Chikyu operation by adapting some of the existing pressure sampling technologies. Hybrid PCS is composed of three main parts: top section for the wireline operation, middle section for the accumulator and pressure controlling system, and the bottom section for the autoclave chamber. The design concept is based on that of Pressure Core Sampler used in Ocean Drilling Program, and of Pressure Temperature Core Sampler (PTCS) and Non-cooled PTCS of Japan Oil, Gas and Metals National Corporation (JOGMEC). Several modifications were made including that on the ball valve, which operates to close the autoclave after coring. The core samples are 51 mm in diameter and up to 3.5 m in length. The system is combined with the Extented Shoe Coring System on the Chikyu and best suited for coring of semi-consolidated formation up to about 3400 m from the sea level. Sample autoclave is compatible with Pressure Core Analysis and Transfer System (PCATS) of Geotek Ltd for sub-sampling and analysis under in-situ pressure. The analysis in PCATS includes X-ray CT scan and core logging with P-wave velocity and gamma density. Depressurization provides accurate volume of gas and its sub-sampling. Hybrid PCS was first tested during the Chikyu Exp. 906 at a submarine mud-volcano in the Nankai Trough. A 0.9 m of hydrate rich material was recovered from the summit (water depth: 2000 m) and the intact hydrate structure was observed by X-ray CT scan. Hybrid PCS was also used in the following JOGMEC methane hydrate cruise, resulting in the good recovery of methane hydrate-bearing cores (approx. 69%).

Kubo, Y.; Mizuguchi, Y.; Inagaki, F.; Eguchi, N.; Yamamoto, K.

2013-12-01

375

Reactor design for nuclear electric propulsion  

NASA Technical Reports Server (NTRS)

The paper analyzes the consequences of heat pipe failures, that resulted in modifications to the basic design of a heat-pipe cooled, fast spectrum nuclear reactor and led to consideration of an entirely different core design. The new design features an integral laminated core configuration consisting of alternating layers of UO2 and molybdenum sheets that span the diameter of the core. Design characteristics are presented and compared for two reactors. A conceptual design for a heat exchanger between the core and the thermionic converter assembly is described. This heat exchanger would provide design and fabrication decoupling of these two assemblies.

Koenig, D. R.; Ranken, W. A.

1979-01-01

376

Overview on Hydrate Coring, Handling and Analysis  

SciTech Connect

Gas hydrates are crystalline, ice-like compounds of gas and water molecules that are formed under certain thermodynamic conditions. Hydrate deposits occur naturally within ocean sediments just below the sea floor at temperatures and pressures existing below about 500 meters water depth. Gas hydrate is also stable in conjunction with the permafrost in the Arctic. Most marine gas hydrate is formed of microbially generated gas. It binds huge amounts of methane into the sediments. Worldwide, gas hydrate is estimated to hold about 1016 kg of organic carbon in the form of methane (Kvenvolden et al., 1993). Gas hydrate is one of the fossil fuel resources that is yet untapped, but may play a major role in meeting the energy challenge of this century. In June 2002, Westport Technology Center was requested by the Department of Energy (DOE) to prepare a ''Best Practices Manual on Gas Hydrate Coring, Handling and Analysis'' under Award No. DE-FC26-02NT41327. The scope of the task was specifically targeted for coring sediments with hydrates in Alaska, the Gulf of Mexico (GOM) and from the present Ocean Drilling Program (ODP) drillship. The specific subjects under this scope were defined in 3 stages as follows: Stage 1: Collect information on coring sediments with hydrates, core handling, core preservation, sample transportation, analysis of the core, and long term preservation. Stage 2: Provide copies of the first draft to a list of experts and stakeholders designated by DOE. Stage 3: Produce a second draft of the manual with benefit of input from external review for delivery. The manual provides an overview of existing information available in the published literature and reports on coring, analysis, preservation and transport of gas hydrates for laboratory analysis as of June 2003. The manual was delivered as draft version 3 to the DOE Project Manager for distribution in July 2003. This Final Report is provided for records purposes.

Jon Burger; Deepak Gupta; Patrick Jacobs; John Shillinglaw

2003-06-30

377

Recent Developments and Adaptations in Diamond Wireline Core Drilling Technology  

NASA Astrophysics Data System (ADS)

Scientific drilling using diamond wireline technology is presently undergoing a significant expansion and extension of activities that has allowed us to recover geologic samples that have heretofore been technically or financially unattainable. Under the direction and management of DOSECC, a high-capacity hybrid core drilling system was designed and fabricated for the Hawaii Scientific Drilling Project (HSDP) in 1998. This system, the DOSECC Hybrid Coring System (DHCS), has the capacity to recover H-sized core from depths of more than 6 km. In 1999, the DHCS completed the first phase of the HSDP to a depth of 3100 m at a substantially lower cost per foot than any previous scientific borehole to comparable depths and, in the process, established a new depth record for recovery of H-sized wireline core. This system has been offered for use in the Unzen Scientific Drilling Project, the Chicxulub (impact crater) Scientific Drilling Project, and the Geysers Deep Geothermal Reservoir Project. More recently, DOSECC has developed a smaller barge-mounted wireline core drilling system, the GLAD800, that is capable of recovering P-sized sediment core to depths of up to 800 m. The GLAD800 has been successfully deployed on Great Salt Lake and Bear Lake in Utah and is presently being mobilized to Lake Titicaca in South America for an extensive core recovery effort there. The coring capabilities of the GLAD800 system will be available to the global lakes drilling community for acquisition of sediment cores from many of the world's deep lakes for use in calibrating and refining global climate models. Presently under development by DOSECC is a heave-compensation system that will allow us to expand the capabilities of the moderate depth coring system to allow us to collect sediment and bottom core from the shallow marine environment. The design and capabilities of these coring systems will be presented along with a discussion of their potential applications for addressing a range of earth sciences questions.

Thomas, D. M.; Nielson, D. L.; Howell, B. B.; Pardey, M.

2001-05-01

378

Dynamics of core accretion  

NASA Astrophysics Data System (ADS)

We perform three-dimensional hydrodynamic simulations of gas flowing around a planetary core of mass Mpl = 10M? embedded in a near Keplerian background flow, using a modified shearing box approximation. We assume an ideal gas behaviour following an equation of state with a fixed ratio of the specific heats, ? = 1.42, consistent with the conditions of a moderate-temperature background disc with solar composition. No radiative heating or cooling is included in the models. We employ a nested grid hydrodynamic code implementing the `Piecewise Parabolic Method' with as many as six fixed nested grids, providing spatial resolution on the finest grid comparable to the present-day diameters of Neptune and Uranus. We find that a strongly dynamically active flow develops such that no static envelope can form. The activity is not sensitive to plausible variations in the rotation curve of the underlying disc. It is sensitive to the thermodynamic treatment of the gas, as modelled by prescribed equations of state (either `locally isothermal' or `locally isentropic') and the temperature of the background disc material. The activity is also sensitive to the shape and depth of the core's gravitational potential, through its mass and gravitational softening coefficient. Each of these factors influences the magnitude and character of hydrodynamic feedback of the small-scale flow on the background, and we conclude that accurate modelling of such feedback is critical to a complete understanding of the core accretion process. The varying flow pattern gives rise to large, irregular eruptions of matter from the region around the core which return matter to the background flow: mass in the envelope at one time may not be found in the envelope at any later time. No net mass accretion into the envelope is observed over the course of the simulation and none is expected, due to our neglect of cooling. Except in cases of very rapid cooling however, as defined by locally isothermal or isentropic treatments, any cooling that does affect the envelope material will have limited consequences for the dynamics, since the flow quickly carries cooled material out of the core's environment entirely. The angular momentum of material in the envelope, relative to the core, varies both in magnitude and in sign on time-scales of days to months near the core and on time-scales a few years at distances comparable to the Hill radius. The dynamical activity contrasts with the largely static behaviour typically assumed within the framework of the core accretion model for Jovian planet formation. We show that material entering the dynamically active environment may suffer intense heating and cooling events the durations of which are as short as a few hours to a few days. Shorter durations are not observable in our work due to the limits of our resolution. Peak temperatures in these events range from T ˜ 1000 K to as high as T ˜ 3-4000 K, with densities ? ˜ 10-9 to 10-8 g cm-3. These time-scales, densities and temperatures span a range consistent with those required for chondrule formation in the nebular shock model. We therefore propose that dynamical activity in the Jovian planet formation environment could be responsible for the production of chondrules and other annealed silicates in the solar nebula.

Nelson, Andrew F.; Ruffert, Maximilian

2013-02-01

379

Design space exploration of photonic interconnects  

E-print Network

As processors scale deep into the multi-core and many-core regimes, bandwidth and energy-efficiency of the on-die interconnect network have become paramount design issues. Recognizing potential limits of electrical ...

Sun, Chen, S.M. Massachusetts Institute of Technology

2011-01-01

380

Variable depth core sampler  

DOEpatents

A variable depth core sampler apparatus comprising a first circular hole saw member, having longitudinal sections that collapses to form a point and capture a sample, and a second circular hole saw member residing inside said first hole saw member to support the longitudinal sections of said first hole saw member and prevent them from collapsing to form a point. The second hole saw member may be raised and lowered inside said first hole saw member.

Bourgeois, Peter M. (Hamburg, NY); Reger, Robert J. (Grand Island, NY)

1996-01-01

381

Variable depth core sampler  

DOEpatents

A variable depth core sampler apparatus is described comprising a first circular hole saw member, having longitudinal sections that collapses to form a point and capture a sample, and a second circular hole saw member residing inside said first hole saw member to support the longitudinal sections of said first hole saw member and prevent them from collapsing to form a point. The second hole saw member may be raised and lowered inside said first hole saw member. 7 figs.

Bourgeois, P.M.; Reger, R.J.

1996-02-20

382

Banded electromagnetic stator core  

DOEpatents

A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups.

Fanning, Alan W. (San Jose, CA); Gonzales, Aaron A. (San Jose, CA); Patel, Mahadeo R. (San Jose, CA); Olich, Eugene E. (Aptos, CA)

1994-01-01

383

Banded electromagnetic stator core  

DOEpatents

A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups. 5 figures.

Fanning, A.W.; Gonzales, A.A.; Patel, M.R.; Olich, E.E.

1994-04-05

384

Banded electromagnetic stator core  

DOEpatents

A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups.

Fanning, Alan W. (San Jose, CA); Gonzales, Aaron A. (San Jose, CA); Patel, Mahadeo R. (San Jose, CA); Olich, Eugene E. (Aptos, CA)

1996-01-01

385

Banded electromagnetic stator core  

DOEpatents

A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups. 5 figs.

Fanning, A.W.; Gonzales, A.A.; Patel, M.R.; Olich, E.E.

1996-06-11

386

Measuring Core Inflation  

Microsoft Academic Search

In this paper, we investigate the use of limited-information estimators as measures of core inflation. Employing a model of asymmetric supply disturbances, with costly price adjustment, we show how the observed skewness in the cross-sectional distribution of inflation can cause substantial noise in the aggregate price index at high frequencies. The model suggests that limited-influence estimators, such as the median

Michael F. Bryan; Stephen G. Cecchetti

1993-01-01

387

Electromagnetic pump stator core  

DOEpatents

A stator core for supporting an electrical coil includes a plurality of groups of circumferentially abutting flat laminations which collectively form a bore and perimeter. A plurality of wedges are interposed between the groups, with each wedge having an inner edge and a thicker outer edge. The wedge outer edges abut adjacent ones of the groups to provide a continuous path around the perimeter. 21 figures.

Fanning, A.W.; Olich, E.E.; Dahl, L.R.

1995-01-17

388

Core-collapse Supernovae  

SciTech Connect

Marking the inevitable death of a massive star, and the birth of a neutron star or black hole, core-collapse supernovae bring together physics at a wide range in spatial scales, from kilometer-sized hydrodynamic motions (growing to gigameter scale) down to femtometer scale nuclear reactions. Carrying 10$^{51}$ ergs of kinetic energy and a rich-mix of newly synthesized atomic nuclei, core-collapse supernovae are the preeminent foundries of the nuclear species which make up ourselves and our solar system. We will discuss our emerging understanding of the convectively unstable, neutrino-driven explosion mechanism, based on increasingly realistic neutrino-radiation hydrodynamic simulations that include progressively better nuclear and particle physics. Recent multi-dimensional models with spectral neutrino transport from several research groups, which slowly develop successful explosions for a range of progenitors, have motivated changes in our understanding of the neutrino reheating mechanism. In a similar fashion, improvements in nuclear physics, most notably explorations of weak interactions on nuclei and the nuclear equation of state, continue to refine our understanding of how supernovae explode. Recent progress on both the macroscopic and microscopic effects that affect core-collapse supernovae are discussed.

Hix, William Raphael [ORNL; Lentz, E. J. [University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL); Baird, Mark L [ORNL; Chertkow, Merek A [ORNL; Lee, Ching-Tsai [University of Tennessee, Knoxville (UTK); Blondin, J. M. [North Carolina State University; Bruenn, S. W. [Florida Atlantic University, Boca Raton; Messer, Bronson [ORNL; Mezzacappa, Anthony [ORNL

2013-01-01

389

Selenium semiconductor core optical fibers  

NASA Astrophysics Data System (ADS)

Phosphate glass-clad optical fibers containing selenium (Se) semiconductor core were fabricated using a molten core method. The cores were found to be amorphous as evidenced by X-ray diffraction and corroborated by Micro-Raman spectrum. Elemental analysis across the core/clad interface suggests that there is some diffusion of about 3 wt % oxygen in the core region. Phosphate glass-clad crystalline selenium core optical fibers were obtained by a postdrawing annealing process. A two-cm-long crystalline selenium semiconductor core optical fibers, electrically contacted to external circuitry through the fiber end facets, exhibit a three times change in conductivity between dark and illuminated states. Such crystalline selenium semiconductor core optical fibers have promising utility in optical switch and photoconductivity of optical fiber array.

Tang, G. W.; Qian, Q.; Peng, K. L.; Wen, X.; Zhou, G. X.; Sun, M.; Chen, X. D.; Yang, Z. M.

2015-02-01

390

The truth about Earth's core?  

NSDL National Science Digital Library

This page uses the 1998 movie The Core (1998) to introduce what we actually know or suspect is true about the Earth's core. Includes discussion of current theories and mysteries from Rich Mueller (UC-Berkeley), with illustrations.

Paul Preuss

391

EEA Technical report No 1/2005 EEA core set of indicators  

E-print Network

EEA Technical report No 1/2005 EEA core set of indicators Guide ISSN 1725-2237 #12;European Environment Agency EEA core set of indicators -- Guide (EEA Technical report No 1/2005 -- ISSN 1725;EEA core set of indicators Guide EEA Technical report No 1/2005 #12;Cover design: EEA Layout: EEA

392

Mechanical response of carbon fiber composite sandwich panels with pyramidal truss cores  

E-print Network

Mechanical response of carbon fiber composite sandwich panels with pyramidal truss cores Tochukwu panel designs offers novel opportunities for ultralight structures. Here, pyramidal truss sandwich cores-predicts the measurements. The CFRP pyramidal cores investigated here have a similar mechanical performance to CFRP

Wadley, Haydn

393

Development of a method for partially uninvaded coring in high-permeability sandstone  

SciTech Connect

A newly designed polycrystalline-diamond-compact (PDC) core bit muds with bridging solids are shown to provide 4-in. diameter cores with a 2.5-in. uninvaded center. High-permeability cored at rates exceeding 90 ft/hr in laboratory and field tests. The mechanisms controlling filtrate invasion are quantified.

Rathmell, J.J.; Warner, H.R. Jr. [Arco E and P Technology, Plano, TX (United States); Tibbitts, G.A. [Hughes-Christensen Co., Salt Lake City, UT (United States); Gremley, R.B.; White, E.K.

1995-06-01

394

Syllabus Format Requirements for the Carolina Core Approval Posted June 2012  

E-print Network

Syllabus Format Requirements for the Carolina Core Approval Process Posted June 2012 Intended Audience for this Syllabus Guide: Faculty proposing courses to satisfy the Carolina Core ­ not students courses. The syllabus needed for proposing an existing course for Carolina Core designation with no other

Almor, Amit

395

Core-Mathematics Project (CPMP)  

NSDL National Science Digital Library

The Core-Mathematics Project (CPMP) involved four years of research, development, and evaluation in over 35 high schools in Alaska, California, Colorado, Georgia, Idaho, Iowa, Kentucky, Michigan, Ohio, South Carolina, and Texas. With funding from the National Science Foundation the project sought to develop student and teacher materials for "a comprehensive Standards-based three-year high school mathematics curriculum for all students, plus a fourth-year course continuing the preparation of students for college mathematics." The four-year curriculum replaces the traditional Algebra-Geometry-Advanced Algebra / Trigonometry-Precalculus sequence by teaching algebra and geometry every year while also introducing new topics such as statistics and discrete mathematics. The curriculum emphasizes mathematical modeling and applications and received the highest designation of "exemplary" from the U.S. Department of Education Expert Panel on Mathematics. Although the CPMP curriculum must be purchased from the publisher Glencoe / McGraw-Hill, sample materials and details about the curriculum, including approaches to assessment and evaluations of the curriculum are available online. The website describes features of the CPMP curriculum, overviews the mathematical content, and discusses issues for instructional design and implementation. Information on upcoming conferences and workshops, and other online articles are also available.

396

Integrally cored ceramic investment casting mold fabricated by ceramic stereolithography  

NASA Astrophysics Data System (ADS)

Superalloy airfoils are produced by investment casting (IC), which uses ceramic cores and wax patterns with ceramic shell molds. Hollow cored superalloy airfoils in a gas turbine engine are an example of complex IC parts. The complex internal hollow cavities of the airfoil are designed to conduct cooling air through one or more passageways. These complex internal passageways have been fabricated by a lost wax process requiring several processing steps; core preparation, injection molding for wax pattern, and dipping process for ceramic shell molds. Several steps generate problems such as high cost and decreased accuracy of the ceramic mold. For example, costly tooling and production delay are required to produce mold dies for complex cores and wax patterns used in injection molding, resulting in a big obstacle for prototypes and smaller production runs. Rather than using separate cores, patterns, and shell molds, it would be advantageous to directly produce a mold that has the casting cavity and the ceramic core by one process. Ceramic stereolithography (CerSLA) can be used to directly fabricate the integrally cored ceramic casting mold (ICCM). CerSLA builds ceramic green objects from CAD files from many thin liquid layers of powder in monomer, which are solidified by polymerization with a UV laser, thereby "writing" the design for each slice. This dissertation addresses the integrally cored casting ceramic mold (ICCM), the ceramic core with a ceramic mold shell in a single patternless construction, fabricated by ceramic stereolithography (CerSLA). CerSLA is considered as an alternative method to replace lost wax processes, for small production runs or designs too complex for conventional cores and patterns. The main topic is the development of methods to successfully fabricate an ICCM by CerSLA from refractory silica, as well as related issues. The related issues are the segregation of coarse fused silica powders in a layer, the degree of segregation parameter to prevent segregation, and sintering and cristobalite transformation in fused silica compacts.

Bae, Chang-Jun

397

Mercury's inner core size and core-crystallization regime  

NASA Astrophysics Data System (ADS)

Earth-based radar observation of Mercury's rotation vector combined with gravity observation by the MESSENGER spacecraft yield a measure of Mercury's moment of inertia and the amplitude of the 88-day libration of its silicate shell. These two geodetic constraints provide information on Mercury's interior structure, including the presence of a fluid core, the radius of the core-mantle boundary and the bulk densities of the core and mantle. In this work, we show how they further provide information on the size of the solid inner core and on the crystallization regime of the fluid core. If Mercury's fluid core is a Fe-FeS alloy with a sulfur concentration on the Fe-rich side of the eutectic, the largest inner core compatible with geodetic observations at the 1? level is 1325 ± 250 km. Our results further suggest that the crystallization scenario that best fits the geodetic observations involves the formation of Fe-snow within the fluid core, and that this scenario is preferred for models with an iron-poor mantle composition. Consequently, Mercury's dynamo most likely operates in concert with snow formation. For an inner core larger than ?650 km, snow formation extends to the inner core boundary. If a dynamo cannot be maintained by the dynamics of snow formation, or if such dynamo produces a magnetic field incompatible with observation, Mercury's inner core must then be smaller than 650 km.

Dumberry, Mathieu; Rivoldini, Attilio

2015-03-01

398

A search for minimum volume of Breed and Burn cores  

SciTech Connect

The objective of the present study is to quantify the minimum volume a Breed and Burn (B and B) core can be designed to have and the corresponding burnup required for sustaining the breed-and-burn mode of operation based on neutronics; radiation damage constraints are ignored. The minimum radius for an idealized spherical B and B reactor is 136 cm or 110 cm for, respectively, 40% or 28% coolant volume fraction. The peak required burnup is about 25%. The minimum volume of a more realistic cylindrical B and B core is estimated to be only {approx}15% larger than that of the idealized spherical core but is only 43% of the volume of the medium-size B and B core previously designed to fit within the S-Prism reactor vessel. Thus it appears that SMR s can, in principle, be designed to have a B and B core. It was also found that the minimum volume B and B core does not necessarily coincide with the maximum permissible leakage from a core that can sustain the B and B mode of operation. (authors)

Di Sanzo, C.; Greenspan, E. [Dept. of Nuclear Engineering, Univ. of California, Berkeley Etcheverry Hall, Berkeley, CA 94720 (United States)

2012-07-01

399

A Technique to Determine Billet Core Charge Weight for P/M Fuel Tubes  

SciTech Connect

The core length in an extruded tube depends on the weight of powder in the billet core. In the past, the amount of aluminum powder needed to give a specified core length was determined empirically. This report gives a technique for calculating the weight of aluminum powder for the P/M core. An equation has been derived which can be used to determine the amount of aluminum needed for P/M billet core charge weights. Good agreement was obtained when compared to Mark 22 tube extrusion data. From the calculated charge weight, the elastomeric bag can be designed and made to compact the U3O8-Al core.

Peacock, H.B.

2001-07-02

400

A New Paradigm for Ice Core Drilling  

NASA Astrophysics Data System (ADS)

The search for answers to questions about the changing climate has created an urgent need to discover past climate signatures archived in glaciers and ice sheets, and to understand current ice sheet behavior. Recognizing that U.S. scientific productivity in this area depends upon a mechanism for ensuring continuity and international cooperation in ice coring and drilling efforts, along with the availability of appropriate drills, drilling expertise, and innovations in drilling technology, the U.S. National Science Foundation (NSF) has established the Ice Drilling Program Office (IDPO) and its partner, the Ice Drilling Design and Operations group (IDDO), together known as IDPO/IDDO (Figure 1). This approach to integrated research and technology planning and delivery replaces the prior approach to drilling, which involved a series of NSF contracts with the Polar Ice Coring Office (PICO) and Ice Coring and Drilling Services (ICDS). This contracting approach lacked integrated planning. Previously, NSF had no way to forecast what science the community would propose—it would get compelling climate proposals that needed ice cores for data, but in many cases no existing drill could retrieve the core needed in the proposal. Constructing the needed drill—a process that takes years—forced science objectives to be put on hold. Now the science community is able to give feedback on its needs to IDPO/IDDO continually, allowing those who develop drilling technology to begin designing and constructing drills that scientists will need for the science proposals that they will submit years in the future. As such, IDPO/IDDO represents a new paradigm for integrated science and science support.

Albert, Mary; Bentley, Charles; Twickler, Mark

2010-09-01

401

Implement of time division multiplexing high speed programmable Viterbi decoder IP core  

NASA Astrophysics Data System (ADS)

The programmable Time Division multiplexing high Viterbi decoder IP core is studied in this paper. According to the characteristics of multiple communication system, the method of programmable time-division multiplexing is puts forward, the high-performance and less resource occupy IP core is designed. Based on SMIC 0.18um CMOS technology, the ASIC of IP core is test. The test results show that the IP core areas, power and frequency could satisfy demand of real-time communication.

Wu, Lan; Chen, Qiliang

2013-03-01

402

Core 4: Image Bank  

NSDL National Science Digital Library

This Image Bank supplements the coursework for Core 4: The Shaping of the Modern World, an introductory course offered by the History Department of Brooklyn College. The Image Bank indexes numerous historical images spanning from the Scientific Revolution to the present. The images are divided into eight major topic indexes: Ancien Regime and Critics; Age of Revolutions; Industry and Society; Liberalism and Nationalism; Varieties of Imperialism; The World Turned Upside Down; Fascism, Depression & WWII; and, The World Since 1945. Indexes for major topics contain clustered subtopics, allowing users to locate relevant images quickly. This Image Bank presents students and educators with a valuable, visual method for understanding Modern Western History.

403

Reuse issues on the verification of embedded MCU cores  

Microsoft Academic Search

The main issues related to the verification of cores embedded in a microcontroller unit (MCU) are addressed in this paper. Issues such as verification environment design, simulation pattern strategies and reuse, as well as standalone and chip level verification are discussed. An analysis of the verification environment is performed from the perspective of the reuse across the design cycle, focussing

A. M. Brochi; T. I. Nunes

2002-01-01

404

Galactic cold cores  

NASA Astrophysics Data System (ADS)

The project Galactic Cold Cores is studying the early stages of Galactic star formation using far-infrared and sub-millimetre observations of dust emission. The Planck satellite has located many sources of cold dust emission that are likely to be pre-stellar clumps in interstellar clouds. We have mapped a sample of Planck-detected clumps with the Herschel satellite at wavelengths 100-500 ?m. Herschel has confirmed the Planck detections of cold dust and have revealed a significant amount of sub-structure in the clumps. The cloud cores have colour temperatures in the range of 10-15 K. However, star formation is often already in progress with cold clumps coinciding with mid-infrared point sources. In less than half of the cases, the cloud morphology is clearly dominated by filamentary structures. The sources include both nearby isolated globules and more distant, massive clouds that may be off-the-plane counterparts of infrared dark clouds. The Herschel observations have been completed and the processed maps will be released to the community in 2013.

Juvela, M.

2015-03-01

405

Embedded Oscillating Starless Cores  

E-print Network

In a previous paper we demonstrated that non-radial hydrodynamic oscillations of a thermally-supported (Bonnor-Ebert) sphere embedded in a low-density, high-temperature medium persist for many periods. The predicted column density variations and molecular spectral line profiles are similar to those observed in the Bok globule B68 suggesting that the motions in some starless cores may be oscillating perturbations on a thermally supported equilibrium structure. Such oscillations can produce molecular line maps which mimic rotation, collapse or expansion, and thus could make determining the dynamical state from such observations alone difficult. However, while B68 is embedded in a very hot, low-density medium, many starless cores are not, having interior/exterior density contrasts closer to unity. In this paper we investigate the oscillation damping rate as a function of the exterior density. For concreteness we use the same interior model employed in Broderick et al. (2007), with varying models for the exterior gas. We also develop a simple analytical formalism, based upon the linear perturbation analysis of the oscillations, which predicts the contribution to the damping rates due to the excitation of sound waves in the external medium. We find that the damping rate of oscillations on globules in dense molecular environments is always many periods, corresponding to hundreds of thousands of years, and persisting over the inferred lifetimes of the globules.

Avery E. Broderick; Ramesh Narayan; Eric Keto; Charles J. Lada

2008-04-10

406

Highly intense upconversion luminescence in Yb/Er:NaGdF4@NaYF4 core-shell nanocrystals with complete shell enclosure of the core.  

PubMed

The purpose of the present work is to demonstrate that the hexagonal Yb/Er:NaGdF4 core size has a great impact on the completeness of the NaYF4 shell covering the core. With the increase of core size, the morphology of core-shell nanocrystals evolves from nanosphere to hexagonal nanoprism and finally to hexagonal nanoplate and, impressively, compared to that on the lateral faces of cores, the shell thickness on the top/bottom faces of cores becomes thinner. The shell growth mechanism is proposed to be the separate nucleation of the shell precursors followed by their ripening-mediated deposition on the cores. Based on this mechanism, controlling the thickness and completeness of the shell on the core can be easily realized by adopting appropriate size cores, which results in the intensification of upconversion luminescence of core-shell nanocrystals 10?000 times as high as that of the core-only ones. Generally, these new findings should be beneficial for designing and fabricating complex core-shell architecture and the understanding of structure-related properties of core-shell nanocrystals. PMID:24945114

Chen, Daqin; Huang, Ping

2014-08-01

407

Core drill and method of removing a core therefrom  

SciTech Connect

This patent describes a method of expediting the removal of a core from the interior of a tubular core drill which comprises: fixedly securing an externally threaded bushing to the rear end of the core drill; providing a sleeve for detachably coupling the bushing-equipped core drill to the externally threaded drive shank of a power unit for the core drill. The coupling sleeve is threaded internally of the opposite ends thereof and respectively sized to mate one with the threaded bushing and one with the threaded drive shank; providing the sleeve with wrench engaging means for the assembly and disassembly thereof to and from the drive shank; and detaching the sleeve from the drive shank and withdrawing by gravity a core through the rear end of the drill stem and coupling sleeve.

Bossler, J.

1987-04-14

408

Two-core optical fiber and its sensing characteristics  

NASA Astrophysics Data System (ADS)

Two-core fiber is a specially designed fiber which contains a pair of parallel fiber core surrounding a cladding with diameter 125?m. A multi-parameters measurement technique that uses a two-core fiber as the sensing element has been proposed and demonstrated in this paper. The theory and the structure design are also introduced. The two-core fiber acts as a two-beam interferometer, in which phase differences is a function of curvature, and the twisting angle in the plane containing the cores results in the shift of the far-field interferometric fringe pattern. This sensor can be used to inspect the structural health monitoring, the measuring angle and the distinguishing direction. Compared to the traditional multi-beam interferometer, this sensor has the such characteristics as small size, good interference, high definition and steady fringe pattern. It does not need considering the effect of the environment temperature. A low-coherence laser diode at wavelength 650nm illuminating the two-cores and the interferogram pattern in the far-field is recorded by a CCD camera. The model of two-core fiber sensor has been established theoretically. The relationship between the far-field fringe pattern intensity distribution and the changes due to the radius of the curvature and the twisting angle are given, and the experimental results also confirmed this.

Wang, Xue; Zhao, Shigang; Yuan, Libo

2007-11-01

409

Status of ASME Section III Task Group on Graphite Support Core Structures  

SciTech Connect

This report outlines the roadmap that the ASME Project Team on Graphite Core Supports is pursuing to establish design codes for unirradiated and irradiated graphite core components during its first year of operation. It discusses the deficiencies in the proposed Section III, Division 2, Subsection CE graphite design code and the different approaches the Project Team has taken to address those deficiencies.

Robert L. Bratton; Tim D. Burchell

2005-08-01

410

Initial Results From the new Long Coring System of RV Knorr  

Microsoft Academic Search

A new long piston coring system has been designed and built for RV Knorr. The system is capable of deploying core lengths up to 46 m and weights of ~25000 lbs. With suitable modifications to other ships, a slightly smaller system could be deployed from other large UNOLS vessels. The handling system was designed around a hybrid rope blend of

W. Curry; L. Keigwin; J. Broda; N. Pisias

2008-01-01

411

Virtual Scan Chains: A Means for Reducing Scan Length in Cores Abhijit Jas, 2  

E-print Network

Virtual Scan Chains: A Means for Reducing Scan Length in Cores 1 Abhijit Jas, 2 Bahram Pouya, and 1-1084 2 Test Technology Group Advanced Products Research & Development Motorola, Austin, TX 78721 Abstract A novel design-for-test (DFT) technique is presented for designing a core with a "virtual scan chain

Touba, Nur A.

412

Coordinated Ocean-ice Reference Experiments (COREs)  

NASA Astrophysics Data System (ADS)

Coordinated Ocean-ice Reference Experiments (COREs) are presented as a tool to explore the behaviour of global ocean-ice models under forcing from a common atmospheric dataset. We highlight issues arising when designing coupled global ocean and sea ice experiments, such as difficulties formulating a consistent forcing methodology and experimental protocol. Particular focus is given to the hydrological forcing, the details of which are key to realizing simulations with stable meridional overturning circulations. The atmospheric forcing from [Large, W., Yeager, S., 2004. Diurnal to decadal global forcing for ocean and sea-ice models: the data sets and flux climatologies. NCAR Technical Note: NCAR/TN-460+STR. CGD Division of the National Center for Atmospheric Research] was developed for coupled-ocean and sea ice models. We found it to be suitable for our purposes, even though its evaluation originally focussed more on the ocean than on the sea-ice. Simulations with this atmospheric forcing are presented from seven global ocean-ice models using the CORE-I design (repeating annual cycle of atmospheric forcing for 500 years). These simulations test the hypothesis that global ocean-ice models run under the same atmospheric state produce qualitatively similar simulations. The validity of this hypothesis is shown to depend on the chosen diagnostic. The CORE simulations provide feedback to the fidelity of the atmospheric forcing and model configuration, with identification of biases promoting avenues for forcing dataset and/or model development.

Griffies, Stephen M.; Biastoch, Arne; Böning, Claus; Bryan, Frank; Danabasoglu, Gokhan; Chassignet, Eric P.; England, Matthew H.; Gerdes, Rüdiger; Haak, Helmuth; Hallberg, Robert W.; Hazeleger, Wilco; Jungclaus, Johann; Large, William G.; Madec, Gurvan; Pirani, Anna; Samuels, Bonita L.; Scheinert, Markus; Gupta, Alex Sen; Severijns, Camiel A.; Simmons, Harper L.; Treguier, Anne Marie; Winton, Mike; Yeager, Stephen; Yin, Jianjun

413

Feasibility study of full-reactor gas core demonstration test  

NASA Technical Reports Server (NTRS)

Separate studies of nuclear criticality, flow patterns, and thermodynamics for the gas core reactor concept have all given positive indications of its feasibility. However, before serious design for a full scale gas core application can be made, feasibility must be shown for operation with full interaction of the nuclear, thermal, and hydraulic effects. A minimum sized, and hence minimum expense, test arrangement is considered for a full gas core configuration. It is shown that the hydrogen coolant scattering effects dominate the nuclear considerations at elevated temperatures. A cavity diameter of somewhat larger than 4 ft (122 cm) will be needed if temperatures high enough to vaporize uranium are to be achieved.

Kunze, J. F.; Lofthouse, J. H.; Shaffer, C. J.; Macbeth, P. J.

1973-01-01

414

Spacecraft transformer and inductor design  

NASA Technical Reports Server (NTRS)

The conversion process in spacecraft power electronics requires the use of magnetic components which frequently are the heaviest and bulkiest items in the conversion circuit. This handbook pertains to magnetic material selection, transformer and inductor design tradeoffs, transformer design, iron core dc inductor design, toroidal power core inductor design, window utilization factors, regulation, and temperature rise. Relationships are given which simplify and standardize the design of transformers and the analysis of the circuits in which they are used. The interactions of the various design parameters are also presented in simplified form so that tradeoffs and optimizations may easily be made.

Mclyman, W. T.

1977-01-01

415

HTTF Core Stress Analysis  

SciTech Connect

In accordance with the need to determine whether cracking of the ceramic core disks which will be constructed and used in the High Temperature Test Facility (HTTF) for heatup and cooldown experiments, a set of calculation were performed using Abaqus to investigate the thermal stresses levels and likelihood for cracking. The calculations showed that using the material properties provided for the Greencast 94F ceramic, cracking is predicted to occur. However, this modeling does not predict the size or length of the actual cracks. It is quite likely that cracks will be narrow with rough walls which would impede the flow of coolant gases entering the cracks. Based on data recorded at Oregon State University using Greencast 94F samples that were heated and cooled at prescribed rates, it was concluded that the likelihood that the cracks would be detrimental to the experimental objectives is small.

Brian D. Hawkes; Richard Schultz

2012-07-01

416

Magnetic and Electrical Characteristics of Permalloy Thin Tape Bobbin Cores  

NASA Technical Reports Server (NTRS)

The core loss, that is, the power loss, of a soft ferromagnetic material is a function of the flux density, frequency, temperature, excitation type (voltage or current), excitation waveform (sine, square, etc.) and lamination or tape thickness. In previously published papers we have reported on the specific core loss and dynamic B-H loop results for several polycrystalline, nanocrystalline, and amorphous soft magnetic materials. In this previous research we investigated the effect of flux density, frequency, temperature, and excitation waveform for voltage excitation on the specific core loss and dynamic B-H loop. In this paper, we will report on an experimental study to investigate the effect of tape thicknesses of 1, 1/2, 1/4, and 1/8-mil Permalloy type magnetic materials on the specific core loss. The test cores were fabricated by winding the thin tapes on ceramic bobbin cores. The specific core loss tests were conducted at room temperature and over the frequency range of 10 kHz to 750 kHz using sine wave voltage excitation. The results of this experimental investigation will be presented primarily in graphical form to show the effect of tape thickness, frequency, and magnetic flux density on the specific core loss. Also, the experimental results when applied to power transformer design will be briefly discussed.

Schwarze, Gene E.; Wieserman, William R.; Niedra, Janis M.

2005-01-01

417

TMI-2 accident: core heat-up analysis. A supplement  

SciTech Connect

Following the accident at Three Mile Island, Unit 2, NSAC mounted an analytical program to develop a chronology of what happened in the core during the period when damage occurred. The central effort and key results of this analytical work are described in NSAC-24, TMI-2 Accident Core Heatup Analysis. Several supporting studies contributed to this central effort. These are presented in this supplement. Part I describes a single pin analysis that was made using the FRAP-T5 code. This analysis provided input to the core damage assessment central effort. Part II describes a thermal hydraulic analysis of the core during the accident using the BOIL 2 code. The BOIL 2 analysis of TMI-2 core was performed to provide an independent check on the results of the main core damage assessment effort. Part III provides the as-built design and material characteristics of the TMI-2 core. This supplement will be of greatest interest to analysts who are studying the TMI-2 accident or are investigating how other cores would behave during a boil-down event.

Not Available

1981-06-01

418

Multi-core advantages for mask data preparation  

NASA Astrophysics Data System (ADS)

Smaller design pattern feature sizes continue to increase mask data file sizes, which increases mask data processing (MDP) times. To satisfy the need for faster turn-around-time, MDP has progressively migrated from single-computer computation, to multi-threading, and then to distributed processing on multiple computers. The availability of low cost multi-core processors can be used advantageously to reduce Mask Data Preparation runtime. Compared to single core processors, multi-core processor have higher performance, however, total available memory and I/O bandwidth need to be increased proportionally with the additional cores. Memory per core and available I/O bandwidth limit the maximum number of cores that can be effective with distributed processing. When a single job is broken down to 2 or more tasks, the granularity of the tasks influences the efficiency of the processing. Smaller tasks allow for smaller memory footprint, better distribution of tasks and increased scalability, but increase input file access time and reduce output data compaction. By choosing a combination of multi-threading and distributed processing, faster run-time and better scalability can be achieved, as compared to either technique alone. The optimal configuration depends on the number of cores per processor, number of processors and memory per core.

Yeap, Johnny; Nogatch, John

2009-04-01

419

Core foundations of abstract geometry.  

PubMed

Human adults from diverse cultures share intuitions about the points, lines, and figures of Euclidean geometry. Do children develop these intuitions by drawing on phylogenetically ancient and developmentally precocious geometric representations that guide their navigation and their analysis of object shape? In what way might these early-arising representations support later-developing Euclidean intuitions? To approach these questions, we investigated the relations among young children's use of geometry in tasks assessing: navigation; visual form analysis; and the interpretation of symbolic, purely geometric maps. Children's navigation depended on the distance and directional relations of the surface layout and predicted their use of a symbolic map with targets designated by surface distances. In contrast, children's analysis of visual forms depended on the size-invariant shape relations of objects and predicted their use of the same map but with targets designated by corner angles. Even though the two map tasks used identical instructions and map displays, children's performance on these tasks showed no evidence of integrated representations of distance and angle. Instead, young children flexibly recruited geometric representations of either navigable layouts or objects to interpret the same spatial symbols. These findings reveal a link between the early-arising geometric representations that humans share with diverse animals and the flexible geometric intuitions that give rise to human knowledge at its highest reaches. Although young children do not appear to integrate core geometric representations, children's use of the abstract geometry in spatial symbols such as maps may provide the earliest clues to the later construction of Euclidean geometry. PMID:23940342

Dillon, Moira R; Huang, Yi; Spelke, Elizabeth S

2013-08-27

420

Silicon Nanophotonics for Many-Core On-Chip Networks  

NASA Astrophysics Data System (ADS)

Number of cores in many-core architectures are scaling to unprecedented levels requiring ever increasing communication capacity. Traditionally, architects follow the path of higher throughput at the expense of latency. This trend has evolved into being problematic for performance in many-core architectures. Moreover, the trends of power consumption is increasing with system scaling mandating nontraditional solutions. Nanophotonics can address these problems, offering benefits in the three frontiers of many-core processor design: Latency, bandwidth, and power. Nanophotonics leverage circuit-switching flow control allowing low latency; in addition, the power consumption of optical links is significantly lower compared to their electrical counterparts at intermediate and long links. Finally, through wave division multiplexing, we can keep the high bandwidth trends without sacrificing the throughput. This thesis focuses on realizing nanophotonics for communication in many-core architectures at different design levels considering reliability challenges that our fabrication and measurements reveal. First, we study how to design on-chip networks for low latency, low power, and high bandwidth by exploiting the full potential of nanophotonics. The design process considers device level limitations and capabilities on one hand, and system level demands in terms of power and performance on the other hand. The design involves the choice of devices, designing the optical link, the topology, the arbitration technique, and the routing mechanism. Next, we address the problem of reliability in on-chip networks. Reliability not only degrades performance but can block communication. Hence, we propose a reliability-aware design flow and present a reliability management technique based on this flow to address reliability in the system. In the proposed flow reliability is modeled and analyzed for at the device, architecture, and system level. Our reliability management technique is superior to existing solutions in terms of power and performance. In fact, our solution can scale to thousand core with low overhead.

Mohamed, Moustafa

421

Quiet Clean Short-Haul Experimental Engine (QCSEE). Preliminary analyses and design report, volume 2  

NASA Technical Reports Server (NTRS)

The experimental and flight propulsion systems are presented. The following areas are discussed: engine core and low pressure turbine design; bearings and seals design; controls and accessories design; nacelle aerodynamic design; nacelle mechanical design; weight; and aircraft systems design.

1974-01-01

422

The GRIP Ice Coring Effort  

NSDL National Science Digital Library

This NOAA website provides a summary of the Greenland Ice Core Project, which resulted in a 3029 m long ice core drilled in Central Greenland from 1989 to 1992. The core reveals information on past environmental and climatic changes that are stored in the ice. Isotopic studies and various atmospheric constituents in the core have revealed a detailed record of climatic variations that span more than 100,000 years. The final report from the project may be downloaded as either a Word or ASCII file.

423

MOX fuel arrangement for nuclear core  

DOEpatents

In order to use up a stockpile of weapons-grade plutonium, the plutonium is converted into a mixed oxide (MOX) fuel form wherein it can be disposed in a plurality of different fuel assembly types. Depending on the equilibrium cycle that is required, a predetermined number of one or more of the fuel assembly types are selected and arranged in the core of the reactor in accordance with a selected loading schedule. Each of the fuel assemblies is designed to produce different combustion characteristics whereby the appropriate selection and disposition in the core enables the resulting equilibrium cycle to closely resemble that which is produced using urania fuel. The arrangement of the MOX rods and burnable absorber rods within each of the fuel assemblies, in combination with a selective control of the amount of plutonium which is contained in each of the MOX rods, is used to tailor the combustion characteristics of the assembly. 38 figs.

Kantrowitz, M.L.; Rosenstein, R.G.

1998-10-13

424

MOX fuel arrangement for nuclear core  

DOEpatents

In order to use up a stockpile of weapons-grade plutonium, the plutonium is converted into a mixed oxide (MOX) fuel form wherein it can be disposed in a plurality of different fuel assembly types. Depending on the equilibrium cycle that is required, a predetermined number of one or more of the fuel assembly types are selected and arranged in the core of the reactor in accordance with a selected loading schedule. Each of the fuel assemblies is designed to produce different combustion characteristics whereby the appropriate selection and disposition in the core enables the resulting equilibrium cycle to closely resemble that which is produced using urania fuel. The arrangement of the MOX rods and burnable absorber rods within each of the fuel assemblies, in combination with a selective control of the amount of plutonium which is contained in each of the MOX rods, is used to tailor the combustion characteristics of the assembly.

Kantrowitz, Mark L. (Portland, CT); Rosenstein, Richard G. (Windsor, CT)

2001-07-17

425

MOX fuel arrangement for nuclear core  

DOEpatents

In order to use up a stockpile of weapons-grade plutonium, the plutonium is converted into a mixed oxide (MOX) fuel form wherein it can be disposed in a plurality of different fuel assembly types. Depending on the equilibrium cycle that is required, a predetermined number of one or more of the fuel assembly types are selected and arranged in the core of the reactor in accordance with a selected loading schedule. Each of the fuel assemblies is designed to produce different combustion characteristics whereby the appropriate selection and disposition in the core enables the resulting equilibrium cycle to closely resemble that which is produced using urania fuel. The arrangement of the MOX rods and burnable absorber rods within each of the fuel assemblies, in combination with a selective control of the amount of plutonium which is contained in each of the MOX rods, is used to tailor the combustion characteristics of the assembly.

Kantrowitz, Mark L. (Portland, CT); Rosenstein, Richard G. (Windsor, CT)

1998-01-01

426

Mox fuel arrangement for nuclear core  

DOEpatents

In order to use up a stockpile of weapons-grade plutonium, the plutonium is converted into a mixed oxide (MOX) fuel form wherein it can be disposed in a plurality of different fuel assembly types. Depending on the equilibrium cycle that is required, a predetermined number of one or more of the fuel assembly types are selected and arranged in the core of the reactor in accordance with a selected loading schedule. Each of the fuel assemblies is designed to produce different combustion characteristics whereby the appropriate selection and disposition in the core enables the resulting equilibrium cycle to closely resemble that which is produced using urania fuel. The arrangement of the MOX rods and burnable absorber rods within each of the fuel assemblies, in combination with a selective control of the amount of plutonium which is contained in each of the MOX rods, is used to tailor the combustion. characteristics of the assembly.

Kantrowitz, Mark L. (Portland, CT); Rosenstein, Richard G. (Windsor, CT)

2001-05-15

427

Power optimization of variable voltage core-based systems  

Microsoft Academic Search

The growing class of portable systems, such as personal computing and communication devices, has resulted in a new set of system design requirements, mainly characterized by dominant importance of power minimization and design reuse. We develop the design methodology for the low power core-based real-time system-on-chip based on dynamically variable voltage hardware. The key challenge is to develop effective scheduling

Inki Hong; Darko Kirovski; Gang Qu; Miodrag Potkonjak; Mani B. Srivastava

1998-01-01

428

Our postgraduate Bioscience courses offer a number of core and optional modules which enable you to effectively design your own course based on your particular areas of interest or specific skill requirements.  

E-print Network

associated with tumour progression, metastasis and current approaches to cancer gene therapy to effectively design your own course based on your particular areas of interest or specific skill requirementscp) You will gain an understanding of the pathogenesis of cancer, cardiovascular disease, diabetes

Evans, Paul

429

One-dimensional mesoporous Fe2O3@TiO2 core-shell nanocomposites: Rational design, synthesis and application as high-performance photocatalyst in visible and UV light region  

NASA Astrophysics Data System (ADS)

An ideal photocatalyst for degradation of organic pollutants should combine the features of efficient visible light response, fast electron transport, high electron-hole separation efficiency, and large specific surface area. However, these requirements usually cannot be achieved simultaneously in the present state-of-the-art research. In this work, we develop a rational synthesis strategy for the preparation of one-dimensional (1D) mesoporous Fe2O3@TiO2 core-shell composites. In this strategy, FeOOH nanorods are firstly coated by TiO2 shell, followed by a calcination process. The as-prepared composites are thoroughly investigated with X-ray powder diffraction, scanning electron microscope, energy dispersive spectroscopy, transmission electron microscope, N2 adsorption-desorption isotherms, UV-visible diffuse-reflectance spectra, and photoluminescence spectra. Endowed with the advantages of its composition and specific structural features, the presented sample possesses the combined advantages mentioned above, thus delivering evidently enhanced photocatalytic activity for the degradation of methyl orange under UV light irradiation and Rhodamine B under visible light irradiation. And the possible mechanism of the enhanced photocatalytic performance is proposed.

Zhang, Xiao; Xie, Yaping; Chen, Haoxin; Guo, Jinxue; Meng, Alan; Li, Chunfang

2014-10-01

430

Multi-chambered integrated power magnetics design  

Microsoft Academic Search

New planar construction alternatives for blending the various power magnetic components of switch mode telecommunications power processing and systems are presented. These unique approaches are based an the use of core designs with multiple winding areas and core sections which provide common flux paths for transformer and inductor operations, arranged so as to minimize magnetic interactions and core material required.

G. Bloom

1998-01-01

431

Multi-chambered planar magnetics design techniques  

Microsoft Academic Search

New planar construction alternatives for blending the various power magnetic components of switch mode power processing circuits and systems are presented. These unique approaches are based on the use of core designs with multiple winding areas and core sections which provide common flux paths for transformer and inductor operations, arranged so as to minimize magnetic interactions and core material required.

Gordon Bloom

2000-01-01

432

Crystalline silicon core fibres from aluminium core preforms.  

PubMed

Traditional fibre-optic drawing involves a thermally mediated geometric scaling where both the fibre materials and their relative positions are identical to those found in the fibre preform. To date, all thermally drawn fibres are limited to the preform composition and geometry. Here, we fabricate a metre-long crystalline silicon-core, silica-cladded fibre from a preform that does not contain any elemental silicon. An aluminium rod is inserted into a macroscopic silica tube and then thermally drawn. The aluminium atoms initially in the core reduce the silica, to produce silicon atoms and aluminium oxide molecules. The silicon atoms diffuse into the core, forming a large phase-separated molten silicon domain that is drawn into the crystalline silicon core fibre. The ability to produce crystalline silicon core fibre out of inexpensive aluminium and silica could pave the way for a simple and scalable method of incorporating silicon-based electronics and photonics into fibres. PMID:25697119

Hou, Chong; Jia, Xiaoting; Wei, Lei; Tan, Swee-Ching; Zhao, Xin; Joannopoulos, John D; Fink, Yoel

2015-01-01

433

Rotating vortex core: An instrument for detecting the core excitations  

E-print Network

Effects of fermionic zero modes (bound states in a vortex core) on the rotational dynamics of vortices with sponaneously broken axisymmetry are considered. The results are compared with the Helsinki experiments where the vortex cores were driven to a fast rotation and torsional oscillations by an NMR r.f. field (Kondo et al, Phys. Rev. Lett. 67, 81 (1991)). We predict a resonance NMR absorption on localized states at the external frequency comparable with the interelevel distance, which is similar to the cyclotron Landau damping. The resonances can experimentally resolve the localized levels in vortex cores. For a pure rotation of the core, the effect depends on the relative signs of the vortex winding number and of the core rotation; thus it is sensitive to the direction of rotation of the container. The similarity with the fermionic zero modes on the fundamental strings, which simulate the thermodynamics of black holes, is discussed.

N. B. Kopnin; G. E. Volovik

1997-12-19

434

IN-CORE FUEL MANAGEMENT: PWR Core Calculations Using MCRAC  

NASA Astrophysics Data System (ADS)

The following sections are included: * INTRODUCTION * IN-CORE FUEL MANAGEMENT CALCULATIONS * In-Core Fuel Management * Methodological Problems of In-Core Fuel Management * In-Core Fuel Management Analytical Tools * PENN STATE FUEL MANAGEMENT PACKAGE * Penn State Fuel Management Package (PFMP) * Assembly Data Description (ADD) * Linking PSU-LEOPARD and MCRAC: An Example * MULTICYCLE REACTOR ANALYSIS CODE (MCRAC) * Main Features and Options of MCRAC code * Core geometry * Diffusion equations * 1.5-group model * Multicycle neutronic analysis * Multicycle cost analysis * Criticality search * Power-dependent xenon feedback calculations * Control rod and burnable absorber simulation * Search for LP with flat BOC power distribution * Artificial ADD option * Variable dimensioning technique * RBI version of MCRAC code * Programming changes in PC version * Fuel interchange option * MCRAC Input/Output * General input description * Sample input * Sample output * EXPERIENCE WITH MCRAC CODE * CONCLUSIONS * REFERENCES

Petrovi?, B. G.

1991-01-01

435

Crystalline silicon core fibres from aluminium core preforms  

NASA Astrophysics Data System (ADS)

Traditional fibre-optic drawing involves a thermally mediated geometric scaling where both the fibre materials and their relative positions are identical to those found in the fibre preform. To date, all thermally drawn fibres are limited to the preform composition and geometry. Here, we fabricate a metre-long crystalline silicon-core, silica-cladded fibre from a preform that does not contain any elemental silicon. An aluminium rod is inserted into a macroscopic silica tube and then thermally drawn. The aluminium atoms initially in the core reduce the silica, to produce silicon atoms and aluminium oxide molecules. The silicon atoms diffuse into the core, forming a large phase-separated molten silicon domain that is drawn into the crystalline silicon core fibre. The ability to produce crystalline silicon core fibre out of inexpensive aluminium and silica could pave the way for a simple and scalable method of incorporating silicon-based electronics and photonics into fibres.

Hou, Chong; Jia, Xiaoting; Wei, Lei; Tan, Swee-Ching; Zhao, Xin; Joannopoulos, John D.; Fink, Yoel

2015-02-01

436

Rolling-Tooth Core Breakoff and Retention Mechanism  

NASA Technical Reports Server (NTRS)

Sampling cores requires the controlled breakoff of the core at a known location with respect to the drill end. An additional problem is designing a mechanism that can be implemented at a small scale that is robust and versatile enough to be used for a variety of core samples. This design consists of a set of tubes (a drill tube and an inner tube) and a rolling element (rolling tooth). An additional tube can be used as a sample tube. The drill tube and the inner tube have longitudinal holes with the axes offset from the axis of each tube. The two eccentricities are equal. The inner tube fits inside the drill tube, and the sample tube fits inside the inner tube. While drilling, the two tubes are positioned relative to each other such that the sample tube is aligned with the drill tube axis and core. The drill tube includes teeth and flutes for cuttings removal. The inner tube includes, at the base, the rolling element implemented as a wheel on a shaft in an eccentric slot. An additional slot in the inner tube and a pin in the drill tube limit the relative motion of the two tubes. While drilling, the drill assembly rotates relative to the core and forces the rolling tooth to stay hidden in the slot along the inner tube wall. When the drilling depth has been reached, the drill bit assembly is rotated in the opposite direction, and the rolling tooth is engaged and penetrates into the core. Depending on the strength of the created core, the rolling tooth can score, lock the inner tube relative to the core, start the eccentric motion of the inner tube, and break the core. The tooth and the relative position of the two tubes can act as a core catcher or core-retention mechanism as well. The design was made to fit the core and hole parameters produced by an existing bit; the parts were fabricated and a series of demonstration tests were performed. This invention is potentially applicable to sample return and in situ missions to planets such as Mars and Venus, to moons such as Titan and Europa, and to comets. It is also applicable to terrestrial applications like forensic sampling and geological sampling in the field.

Badescu, Mircea; Bickler, Donald B.; Sherrit, Stewart; Bar-Cohen, Yoseph; Bao, Xiaoqi; Hudson, Nicolas H.

2011-01-01

437

Gas core reactors for actinide transmutation and breeder applications  

NASA Technical Reports Server (NTRS)

This work consists of design power plant studies for four types of reactor systems: uranium plasma core breeder, uranium plasma core actinide transmuter, UF6 breeder and UF6 actinide transmuter. The plasma core systems can be coupled to MHD generators to obtain high efficiency electrical power generation. A 1074 MWt UF6 breeder reactor was designed with a breeding ratio of 1.002 to guard against diversion of fuel. Using molten salt technology and a superheated steam cycle, an efficiency of 39.2% was obtained for the plant and the U233 inventory in the core and heat exchangers was limited to 105 Kg. It was found that the UF6 reactor can produce high fluxes (10 to the 14th power n/sq cm-sec) necessary for efficient burnup of actinide. However, the buildup of fissile isotopes posed severe heat transfer problems. Therefore, the flux in the actinide region must be decreased with time. Consequently, only beginning-of-life conditions were considered for the power plant design. A 577 MWt UF6 actinide transmutation reactor power plant was designed to operate with 39.3% efficiency and 102 Kg of U233 in the core and heat exchanger for beginning-of-life conditions.

Clement, J. D.; Rust, J. H.

1978-01-01

438

The EPOS Integrated Core Services  

NASA Astrophysics Data System (ADS)

The European Plate Observing System (EPOS) is integrating the diverse, but advanced Research Infrastructures in Europe for solid Earth Science, and will build on new e-science opportunities to monitor and understand the dynamic and complex solid-Earth System. This integration requires a significant coordination between, among others, disciplinary (thematic) communities, national RIs policies and initiatives, and geo- and IT-scientists. The RIs that EPOS will coordinate include at least, but not only: regionally-distributed geophysical observing systems (seismological and geodetic networks), local observatories (including geomagnetic, permanent in-situ and volcano observatories), experimental & analogue laboratories in Europe, integrated satellite data and geological information. EPOS is promoting open access to geophysical and geological data as well as modelling/processing tools, enabling a step change in multidisciplinary scientific research for Earth Sciences The EPOS e-infrastructure is developed through strawman (initial design / architecture), woodman (refined design/architecture) and ironman (final design/architecture) phases. Midway in the project we are in the woodman phase based on extensive primary requirements from users and secondary requirements for interoperation with other geoscience systems, other European environmental research infrastructure projects and e-infrastructure projects (e.g. EUDAT). The EPOS e-infrastructure is being developed along 3 parallel tracks: (a) an inventory of assets offered by organisations within the EPOS community. The RIDE (Research Infrastructure Database for EPOS) system from the strawman phase is being extended in the woodman phase to the metadata catalog describing computing and scientific resources, data, services (software), and users which will drive the EPOS e-infrastructure; (b) refining an architecture to meet the requirements. This is an iterative process with the working groups (organised thematically) within EPOS also including other work packages in EPOS such as those concerned with legalistics and financing; (c) a prototype based on the woodman architecture in one domain (seismology) to provide assurance that the architecture is valid. The key aspect is the metadata catalog. In one dimension this is described in 3 levels: (1) discovery metadata using well-known and commonly used standards such as DC (Dublin Core) to enable users (via an intelligent user interface) to search for objects within the EPOS environment relevant to their needs; (2) contextual metadata providing the context of the object described in the catalog to enable a user or the system to determine the relevance of the discovered object(s) to their requirement - the context includes projects, funding, organisations involved, persons involved, related publications, facilities, equipment etc and utilises CERIF (Common European Research Information Format) see www.eurocris.org ; (3) detailed metadata which is specific to a domain or to a particular object and includes the schema describing the object to processing software. The other dimension of the metadata concerns the objects described. These are classified into users, services (including software), data and resources (computing, data storage, instruments and scientific equipment). The core services include not only user access to data, software, services, equipment and associated processing but also facilities for interaction and cooperative working between users and storage of history and experience. EPOS will operate a full e-Science environment including metadata and persistent identifiers.

Jeffery, Keith; Michelini, Alberto; Bailo, Daniele

2013-04-01

439

Design review report for the hydrogen interlock preliminary design  

SciTech Connect

This report documents the completion of a preliminary design review for the hydrogen interlock. The hydrogen interlock, a proposed addition to the Rotary Mode Core Sampling (RMCS) system portable exhauster, is intended to support core sampling operations in waste tanks requiring flammable gas controls. The objective of this review was to validate basic design assumptions and concepts to support a path forward leading to a final design. The conclusion reached by the review committee was that the design was acceptable and efforts should continue toward a final design review.

Corbett, J.E.

1996-01-01

440

Understanding Common Core State Standards  

ERIC Educational Resources Information Center

Now that the Common Core standards are coming to just about every school, what every school leader needs is a straightforward explanation that lays out the benefits of the Common Core in plain English, provides a succinct overview, and gets everyone thinking about how to transition to this promising new paradigm. This handy, inexpensive booklet…

Kendall, John S.

2011-01-01

441

Structure of neutron star cores  

NASA Technical Reports Server (NTRS)

After reviewing the outer and central regions of a neutron star, we discuss the central region and the possibility that the core has a solid structure. We present the work of different groups on the solidification problem, suggesting that the neutron star-cores are indeed solid.

Canuto, V.; Datta, B.; Lodenquai, J.

1975-01-01

442

Viscosity of the Earth's Core  

Microsoft Academic Search

The viscosity of the earth's core is probably the least well-known physical property of the earth. Miki [1952] gives an estimate, based on a theoretical calculation, that the dynamic viscosity lies between 10 - and 10 - poise. Malkus [1968] suggests the range 10 -' to 1 poise. Attenuation of S waves reflected from the core [Sato and Espinosa, 1967b;

Roger F. Gans

1972-01-01

443

Kinetic constraints on core formation  

Microsoft Academic Search

According to recent models of core formation, a metallic liquid equilibrated in an early magma ocean and subsequently descended through the crystalline lower mantle to form the protocore. In this study we are investigating the extent to which the metal would further equilibrate with crystalline material of the lower mantle given reasonable time scales of core formation. For this purpose,

C. Holzapfel; D. C. Rubie; D. J. Frost

2003-01-01

444

Heat recuperator having ceramic core  

Microsoft Academic Search

This patent describes a recuperator comprising a ceramic heat-exchanger core within a housing, the core having six faces, two solid and four having openings for the flow of gas therethrough, the improvement comprising a layer of intumescent material disposed between a solid face and the housing.

Kohnken

1987-01-01

445

The Common Core Takes Hold  

ERIC Educational Resources Information Center

A survey administered in the spring of 2013 by the Center on Education Policy (CEP) inquired into the implementation of Common Core State Standards at that time. Based on self-reports by state officials, the survey found that curricula aligned to the common core were already being taught in at least some districts or grade levels. All states…

Rothman, Robert

2014-01-01

446

Business Planning Core Facilities  

PubMed Central

Thoughtful business planning is pivotal to the success of any business/operational venture. When planned in a thoughtful and detailed manner there are very few operational or financial surprises for an institution or facility (service center) to contend with. At Stony Brook Medicine we include SWOT analysis and a detailed Market Analysis as part of the process. This is bolstered by an initiative to ensure institutional policies are met so that facilities remain in compliance throughout their lifecycle. As we operate 14 facilities we have had the opportunity to become creative in our approach to coordinate activities, virtualize services, integrate new software business-to-business partners, and finally coordinate plans for phased consolidation instead of outright termination of services when required. As the Associate Dean for Scientific Operations and Research Facilities, the shared research facilities (cores) of the Medical School are in my direct line of sight. We understand their value to the meeting our overall research mission. We have found that an active process of monitoring to predict trouble as much as possible is the best approach for facilities. Some case analysis of this type of interaction will be presented as well.

Itzkowitz, G.N.

2014-01-01

447

Core compressor exit stage study, 2  

NASA Technical Reports Server (NTRS)

A total of two three-stage compressors were designed and tested to determine the effects of aspect ratio on compressor performance. The first compressor was designed with an aspect ratio of 0.81; the other, with an aspect ratio of 1.22. Both compressors had a hub-tip ratio of 0.915, representative of the rear stages of a core compressor, and both were designed to achieve a 15.0% surge margin at design pressure ratios of 1.357 and 1.324, respectively, at a mean wheel speed of 167 m/sec. At design speed the 0.81 aspect ratio compressor achieved a pressure ratio of 1.346 at a corrected flow of 4.28 kg/sec and an adiabatic efficiency of 86.1%. The 1.22 aspect ratio design achieved a pressure ratio of 1.314 at 4.35 kg/sec flow and 87.0% adiabatic efficiency. Surge margin to peak efficiency was 24.0% with the lower aspect ratio blading, compared with 12.4% with the higher aspect ratio blading.

Behlke, R. F.; Burdsall, E. A.; Canal, E., Jr.; Korn, N. D.

1979-01-01

448

SCDAP/RELAP5 lower core plate model  

SciTech Connect

The SCDAP/RELAP5 computer code is a best-estimate analysis tool for performing nuclear reactor severe accident simulations. This report describes the justification, theory, implementation, and testing of a new modeling capability which will refine the analysis of the movement of molten material from the core region to the vessel lower head. As molten material moves from the core region through the core support structures it may encounter conditions which will cause it to freeze in the region of the lower core plate, delaying its arrival to the vessel head. The timing of this arrival is significant to reactor safety, because during the time span for material relocation to the lower head, the core may be experiencing steam-limited oxidation. The time at which hot material arrives in a coolant-filled lower vessel head, thereby significantly increasing the steam flow rate through the core region, becomes significant to the progression and timing of a severe accident. This report is a revision of a report INEEL/EXT-00707, entitled ``Preliminary Design Report for SCDAP/RELAP5 Lower Core Plate Model''.

Coryell, E.W.; Griffin, F.P.

1999-09-01

449

SCDAP/RELAP5 Lower Core Plate Model  

SciTech Connect

The SCDAP/RELAP5 computer code is a best-estimate analysis tool for performing nuclear reactor severe accident simulations. This report describes the justification, theory, implementation, and testing of a new modeling capability which will refine the analysis of the movement of molten material from the core region to the vessel lower head. As molten material moves from the core region through the core support structures it may encounter conditions which will cause it to freeze in the region of the lower core plate, delaying its arrival to the vessel head. The timing of this arrival is significant to reactor safety, because during the time span for material relocation to the lower head, the core may be experiencing steam-limited oxidation. The time at which hot material arrives in a coolant-filled lower vessel head, thereby significantly increasing the steam flow rate through the core region, becomes significant to the progression and timing of a severe accident. This report is a revision of a report INEEL/EXT-00707, entitled "Preliminary Design Report for SCDAP/RELAP5 Lower Core Plate Model".

Coryell, Eric Wesley; Griffin, F. P.

1999-10-01

450

Uncovering the information core in recommender systems  

PubMed Central

With the rapid growth of the Internet and overwhelming amount of information that people are confronted with, recommender systems have been developed to effectively support users' decision-making process in online systems. So far, much attention has been paid to designing new recommendation algorithms and improving existent ones. However, few works considered the different contributions from different users to the performance of a recommender system. Such studies can help us improve the recommendation efficiency by excluding irrelevant users. In this paper, we argue that in each online system there exists a group of core users who carry most of the information for recommendation. With them, the recommender systems can already generate satisfactory recommendation. Our core user extraction method enables the recommender systems to achieve 90% of the accuracy of the top-L recommendation by taking only 20% of the users into account. A detailed investigation reveals that these core users are not necessarily the large-degree users. Moreover, they tend to select high quality objects and their selections are well diversified. PMID:25142186

Zeng, Wei; Zeng, An; Liu, Hao; Shang, Ming-Sheng; Zhou, Tao

2014-01-01

451

Uncovering the information core in recommender systems  

NASA Astrophysics Data System (ADS)

With the rapid growth of the Internet and overwhelming amount of information that people are confronted with, recommender systems have been develope