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1

Bursts of electron cyclotron emission during disruptions of high beta discharges in the Tokamak Fusion Test Reactor tokamak  

SciTech Connect

Disruptions are sudden terminations of tokamak plasma discharges. During disruptions at high beta {beta} where {beta}{equivalent_to}plasma pressure/magnetic pressure, short (order of {mu}s) and intense bursts of electron cyclotron emission (ECE), an order magnitude above thermal levels, are observed in the second harmonic electron cyclotron frequency range, which corresponds to 100s of GHz in the Tokamak Fusion Test Reactor tokamak. A unique combination of two, fast, 500 kHz, 20-channel grating polychromator instruments, located at different toroidal positions, is used to measure the emission and characterize these bursts. New insights into the three-dimensional dynamics of these disruptions and the accompanying bursts of ECE have been obtained. Bursts of ECE occur at the beginning of the thermal quenches and exhibit strong toroidal asymmetries. Bursts are localized to the vicinity of the ballooning mode, a fast growing (few ms) medium toroidal mode number (n=10{endash}20) precursor, localized toroidally, poloidally, and radially, which triggers the disruptions. Fast-particle losses occur with the explosive growth of the ballooning mode, followed by plasma/wall interaction. Bursts of ECE occur shortly afterwards, within 10s of {mu}s of the fast particle losses. An explanation of the bursting is presented which is consistent both qualitatively and quantitatively, with observations predicting, for example, radiation enhancement factors of {approx}10. Bursting can be explained in terms of the reduction of absorption of thermal emission. Bursting is consistent with a modification to the electron distribution function f{sub e} due to a rapid energy or particle exchange between hot electrons and cold electrons from the edge, momentarily reducing the velocity gradient of f{sub c} in the thermal region. Large edge localized mode events also exhibit bursts of ECE due to a similar sequence of events. {copyright} {ital 1997 American Institute of Physics.}

Janos, A.; McGuire, K.; Fredrickson, E.; Parks, W.; Zweben, S. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Hastie, J. [UKAEA, Culham, Abingdon, Oxon OX14 3DB (United Kingdom)

1997-01-01

2

Characteristics of confinement and fusion reactivity in JT-60U high-{beta}{rho} and TFTR supershot regimes with deuterium neutral beam injection  

SciTech Connect

The high performance regimes achieved in JT-60U and TFTR have produced peak DD fusion neutron rates up to 5.6 {times} 10{sup 16}/s for similar heating beam powers, in spite of considerable differences in machine operation and plasma configuration. A common scaling for the DD fusion neutron rate (S{sub DD} {proportional_to} P{sub abs}{sup 2.0} H{sub ne} V{sub p}{sup {minus}0.9}) is obtained, where P{sub abs} and H{sub ne} are the absorbed beam power and beam fueling peaking factor, respectively, and V{sub p} is the plasma volume. The maximum stored energy obtained in each machine has been up to 5.4 MJ in TFTR and 8.7 MJ in JT-60U. Further improvements in the fusion neutron rate and the stored energy are limited by the {beta}-limit in Troyon range, {beta}{sub N} {approximately} 2.0--2.5. A common scaling for the stored energy (W{sub tot} {proportional_to} P{sub abs}V{sub p}H{sub ne}{sup 0.2}) is also proposed.

Park, H.K.; Bell, M.G.; Yamada, M.

1995-03-01

3

High Beta Tokamaks  

SciTech Connect

Perhaps the ideal tokamak would have high {beta} ({beta} {approx}> 1) and classical confinement. Such a tokamak has not been found, and we do not know if one does exist. We have searched for such a possibility, so far without success. In 1990, we obtained analytic equilibrium solutions for large aspect ratio tokamaks at {beta} {approx} {Omicron}(1) [1]. These solutions and the extension at high {beta} poloidal to finite aspect ratio [2] provided a basis for the study of high {beta} tokamaks. We have shown that these configurations can be stable to short scale MHD modes [3], and that they have reduced neoclassical transport [4]. Microinstabilities (such as the {del}T{sub i} mode) seem to be stabilized at high {beta} [5] - this is due to the large local shear [3] and the magnetic well. We have some concerns about modes associated with the compressional branch which may appear at high {beta}. Bill Dorland and Mike Kotschenreuther have studied this issue and our concerns may be unfounded. It is certainly tantalizing, especially given the lowered neoclassical transport values, that these configurations could have no microinstabilities and, one could assume, no anomalous transport. Unfortunately, while this work is encouraging, the key question for high {beta} tokamaks is the stability to large scale kink modes. The MHD {beta} limit (Troyon limit) for kink modes at large aspect ratio is problematically low. There is ample evidence from computations that the limit exists. However, it is not known if stable equilibria exist at much higher {beta}--none have been found. We have explored this question in the asymptotic high {beta} poloidal limit. Unfortunately, we are unable to find stable equilibrium and also unable to show that they don't exist. The results of these calculations will be published when a more definitive answer is found.

Cowley, S.

1998-11-14

4

An efficient downstream box fusion allows high-level accumulation of active bacterial beta-glucosidase in tobacco chloroplasts.  

PubMed

Production of enzymes for lignocellulose hydrolysis in planta has been proposed as a lower-cost alternative to microbial production, with plastid transformation as a preferred method due to high foreign protein yields. An important regulator of chloroplast protein production is the downstream box (DB) region, located immediately downstream of the start codon. Protein accumulation can vary over several orders of magnitude by altering the DB region. Experiments in bacteria have suggested that these differences in protein accumulation may result from changes in translation efficiency, though the precise mechanism of DB function is not known. In this study, three DB regions were fused to the bglC ORF encoding a ?-glucosidase from the thermophilic bacterium Thermobifida fusca and inserted into the tobacco (Nicotiana tabacum) plastid genome. More than a two order of magnitude of difference in BglC protein accumulation was observed, dependent on the identity of the DB fusion. Differential transcript accumulation explained some the observed differences in protein accumulation, but in addition, less 3' degradation of bglC transcripts was observed in transgenic plants that accumulated the most BglC enzyme. Chloroplast-produced BglC was active against both pure cellobiose and against tobacco lignocellulose. These experiments demonstrate the potential utility of transplastomic plants as a vehicle for heterologous ?-glucosidase production for the cellulosic ethanol industry. PMID:21279422

Gray, Benjamin N; Yang, Huijun; Ahner, Beth A; Hanson, Maureen R

2011-01-30

5

(High beta tokamak research)  

SciTech Connect

Our activities on High Beta Tokamak Research during the past 20 months of the present grant period can be divided into six areas: reconstruction and modeling of high beta equilibria in HBT; measurement and analysis of MHD instabilities observed in HBT; measurements of impurity transport; diagnostic development on HBT; numerical parameterization of the second stability regime; and conceptual design and assembly of HBT-EP. Each of these is described in some detail in the sections of this progress report.

Not Available

1989-01-01

6

High-beta steady-state research and future directions on the Japan Atomic Energy Research Institute Tokamak60 Upgrade and the Japan Atomic Energy Research Institute Fusion Torus2 Modified  

Microsoft Academic Search

In the Japan Atomic Energy Research Institute Tokamak-60 Upgrade (JT-60U), a high-betap ELMy H-mode (high-poloidal-beta high-confinement-mode with edge localized mode) plasma was sustained with betaN~2.7 for 7.4 s. Real-time neoclassical tearing mode (NTM) stabilization system was established and effective NTM suppression by early electron cyclotron (EC) wave injection was demonstrated. High fusion triple product of ni(0)tauETi(0)=3.1×1020 keV.s.m-3 was achieved using

S. Ishida

2004-01-01

7

Wall-confined high beta spheromak  

SciTech Connect

The spheromak could be extended into the high beta regime by supporting the pressure on flux-conserving walls, allowing the plasma to be in a Taylor state with zero pressure gradient and thus stable to ideal and resistive MHD. The concept yields a potentially attractive, pulsed reactor which would require no external magnets. The flux conserver would be shaped to be stable to the tilt and shift instabilities. We envision a plasma which is ohmically ignited at low beta, with the kinetic pressure growing to beta > 1 by fueling from the edge. The flux conserver would be designed such that the magnetic decay time = the fusion burn time. The thermal capacity of the flux conserver and blanket would exceed the fusion yield per discharge, so that they can be cooled steadily. Ignition is estimated to require minimum technology: 30-100 MJ of pulsed power applied at a 0.5 GW rate generates an estimated bum yield > 1 GJ. The concept thus provides an alternate route to a fusion plasma that is MHD stable at high beta, yielding a reactor that is simple and cheap. The major confinement issue is transport due to grad(T), e.g. driven by high beta modes related to the ITG instability.

Fowler, T.K.; Hopper, E.B.; Moir, R.W.; Pearlstein, L.D.

1998-03-16

8

Pulsed High Density Fusion  

Microsoft Academic Search

Based on FRC acceleration experiments, together with confinement scaling observed in past FRC experiments, a method has been determined by which an FRC can be compressed to high density and brought to ignition conditions in a rapid, repetitive manner. This regime is referred to as the Pulsed High Density (PHD) regime of MFE. Unlike MTF, the upper boundary of this

John Slough

2000-01-01

9

Antibody-NKG2D Ligand (Rae-1Beta) Fusion Protein for Breast Cancer Therapy.  

National Technical Information Service (NTIS)

Antibody-NKG2D ligand fusion protein targeted against the breast tumor antigen HER2. Using murine breast tumors designed to express the HER2 target antigen and the murine NKG2D ligand Rae-1BETA, we constructed an anti- HER2 IgG3-CH3-Rae-1BETA fusion prote...

S. Shin

2005-01-01

10

A novel delta beta fusion gene expresses hemoglobin A (HbA) not Hb Lepore: Senegalese delta(0)beta(+) thalassemia.  

PubMed

This study identified and characterized a novel delta beta fusion gene in which the delta-globin gene promoter is linked to intact beta-globin coding sequences in a Senegalese family. It results from a 7.4-kb deletion that removes the delta-globin coding sequences, the delta beta intergenic region as well as the beta-globin gene promoter and causes delta(0)beta(+) thalassemia with hemoglobin A expressed at the 11% to 15% range. The phenotype of this naturally occurring delta beta hybrid gene not only clarifies, in an in vivo context, the respective strength of delta- and beta-globin gene promoters, but also emphasizes the importance of beta-globin intragenic sequences in the expression of beta-globin chains. (Blood. 2001;98:1261-1263) PMID:11493481

Zertal-Zidani, S; Ducrocq, R; Weil-Olivier, C; Elion, J; Krishnamoorthy, R

2001-08-15

11

Efficacy of posterior cervical fusions utilizing an artificial bone graft expander, beta tricalcium phosphate  

PubMed Central

Background: Several cervical laminectomies and instrumented posterior cervical fusions utilize iliac autograft supplemented with demineralized bone matrix, or bone morphogenetic protein, but few utilize artificial bone graft expanders. Here we analyzed whether posterior cervical fusions could effectively utilize iliac autograft supplemented with an artificial bone graft expander, Beta Tricalcium Phosphate [B-TCP] Materials and Methods: Fifty-three severely myelopathic patients [average Nurick Score 4.1], averaging 65.3 years of age, underwent posterior cervical laminectomies [average 2.3 levels] and multilevel instrumented fusions [average 7.5 levels] utilizing iliac crest autograft and B-TCP. Pathology addressed included multilevel spondylosis accompanied by ossification of the posterior longitudinal ligament [24 patients], ossification of the yellow ligament [27 patients], and instability [53 patients]. Fusion rates [dynamic X-ray, two-dimensional computerized axial tomography (2D-CT) and outcomes [Nurick Grades, Odom's Criteria, SF-36] were assessed at 3, 6, and 12 months postoperatively. Results: Fusion was confirmed by two independent neuroradiologists utilizing dynamic X-ray studies [100% of patients] and 2D-CT studies [86.8% of patients] an average of 5.4 months postoperatively. Although there were no symptomatic pseudarthroses, three smokers exhibited delayed fusions [8 postoperative months]. Within 1 postoperative year, patients improved an average of 2.7 Nurick Grades [Nurick Score 1.4], Odom's criteria revealed 48 good/excellent, and 5 fair/poor outcomes, and improvement on all 8 SF-36 Health Scales [maximal on Bodily Pain [+21.96]. Conclusions: High fusion rates and improved neurological outcomes were achieved within one year for 53 patients undergoing multilevel level cervical laminectomies with posterior instrumented fusions utilizing iliac autograft supplemented with B-TCP.

Epstein, Nancy E.

2011-01-01

12

High-density-plasma diagnostics in magnetic-confinement fusion  

SciTech Connect

The lectures will begin by defining high density in the context of magnetic confinement fusion research and listing some alternative reactor concepts, ranging from n/sub e/ approx. 2 x 10/sup 14/ cm/sup -3/ to several orders of magnitude greater, that offer potential advantages over the main-line, n/sub e/ approx. 1 x 10/sup 14/ cm/sup -3/, Tokamak reactor designs. The high density scalings of several major diagnostic techniques, some favorable and some disadvantageous, will be discussed. Special emphasis will be given to interferometric methods, both electronic and photographic, for which integral n/sub e/dl measurements and associated techniques are accessible with low wavelength lasers. Reactor relevant experience from higher density, smaller dimension devices exists. High density implies high ..beta.., which implies economies of scale. The specialized features of high ..beta.. diagnostics will be discussed.

Jahoda, F.C.

1982-01-01

13

HYFIRE: Fusion-High Temperature Electrolysis System.  

National Technical Information Service (NTIS)

The Brookhaven National Laboratory (BNL) is carrying out a comprehensive conceptual design study called HYFIRE of a commercial fusion Tokamak reactor, high-temperature electrolysis system. The study is placing particular emphasis on the adaptability of th...

J. A. Fillo J. R. Powell M. Steinberg R. Benenati V. D. Dang

1980-01-01

14

A full wave theory of high-harmonic fast wave absorption in high-beta plasmas  

NASA Astrophysics Data System (ADS)

A theory of fast wave absorption in a high-beta plasma is given. A reduced, second-order, ordinary differential equation has been used which includes all collisionless electron dissipation mechanisms and ion cyclotron damping over many harmonics. This is relevant to the high-harmonic fast wave heating scheme proposed by Ono [Phys. Plasmas 2, 4075 (1995)]. The parameters appropriate to the National Spherical Tokamak Experiment NSTX [J. Spitzer et al., Fusion Technol. 30, 1337 (1996)] have been used to investigate the absorption characteristics of electrons and ions under high-beta, high-harmonic conditions.

Lashmore-Davies, C. N.; Fuchs, V.; Cairns, R. A.

1998-06-01

15

Expression of a mouse metallothionein-Escherichia coli. beta. -galactosidase fusion gene (MT-. beta. gal) in early mouse embryos  

SciTech Connect

The authors have microinjected DNA containing the inducible mouse metallothionein-I (MT-I) promoter, coupled to the structural gene for Escherichia coli {beta}-galactosidase (lacZ), into the pronuclei of one-cell mouse embryos. A qualitative histochemical assay, with 5-bromo-4-chloro-3-indolyl {beta}-D-galactopyranoside (X-Gal) as a substrate, was used to detect expression of lacZ at several preimplantation stages. They observed staining indicative of exogenous {beta}-galactosidase activity in 5-17% of DNA-injected embryos assayed at preimplantation stages after 16-24 h treatment with ZnSO{sub 4}. Thus, lacZ can be used as an indicator gene for promoter function during early mouse embryogenesis, and the incorporation of the MT-I promoter into fusion genes can be a useful means of controlling the expression of exogenous genes in preimplantation mouse embryos.

Stevens, M.E.; Meneses, J.J.; Pedersen, R.A. (Univ. of California, San Francisco (United States))

1989-08-01

16

Fusion - High performance computing in magnetic fusion energy research  

Microsoft Academic Search

Obtaining energy from nuclear fusion requires heating the fuel to about 100 times the temperature of the sun to produce a plasma, and holding the hot plasma long enough for fusion reactions to produce a net energy gain. In a magnetic fusion device, this plasma is maintained in a largely self-organized state that far from equilibrium the mathematical description of

Donald B. Batchelor

2006-01-01

17

Formation of High-Beta Plasma and Stable Confinement of Toroidal Electron Plasma in RT1  

Microsoft Academic Search

The Ring Trap 1 (RT-1) device is a laboratory magnetosphere generated by a levitated superconducting magnet. The goals of RT-1 are to realize stable formation of ultra high-beta plasma suitable for burning advanced fusion fuels, and confinement of toroidal non-neutral plasmas including antimatter particles. RT- 1 has produced high-beta plasma in the magnetospheric configuration. The effects of coil levitation and

Haruhiko Saitoh

2010-01-01

18

Critical elements of high gain laser fusion  

Microsoft Academic Search

Progress toward high laser fusion can be measured by a set of five critical elements. They are: (1) the laser-to-fuel coupling efficiency, (2) the cold fuel isentrope, (3) the implosion symmetry, (4) the ablation pressure, and (5) the ignition concept.

Stephen E. Bodner

1981-01-01

19

High-intensity lasers and controlled fusion  

NASA Astrophysics Data System (ADS)

The use of high-intensity lasers to cause ignition in inertial confinement fusion is presented, with emphasis on current experimental programs and physical concepts that are at the forefront of the field. In particular, we highlight the issues of fast electron transport through dense materials, an essential element of the “Fast Ignitor” concept.

Freeman, R. R.; Anderson, C.; Hill, J. M.; King, J.; Snavely, R.; Hatchett, S.; Key, M.; Koch, J.; MacKinnon, A.; Stephens, R.; Cowan, T.

2003-10-01

20

Energy-confinement scaling for high-beta plasmas in the W7-AS stellarator.  

PubMed

High-beta energy-confinement data are subjected to comparisons of scaling invariant, first-principles physical models. The models differ in the inclusion of basic equations indicating the nature of transport. The result for high-beta data of the W7-AS stellarator is that global transport is described best with a collisional high-beta model, which is different from previous outcomes for low-beta data. Model predictive calculations indicate the validation of energy-confinement prediction with respect to plasma beta and collisionality nu*. The finding of different transport behaviors in distinct beta regimes is important for the development of fusion energy based on magnetic confinement and for the assessment of different confinement concepts. PMID:18233454

Preuss, R; Dinklage, A; Weller, A

2007-12-11

21

Training The Next Generation Of Fusion Scientists And Engineers: Summer High School Fusion Science Workshop  

Microsoft Academic Search

The goal of the education and outreach activities of the Hampton University Center for Fusion Research and Training (HU CFRT) is to create a high school-to-Ph.D. pipeline in plasma physics, fusion science, and related sciences for underrepresented minorities and female students. The HU CFRT Summer High School Fusion Research Workshop is an integral component of this pipeline. This workshop has

Alkesh Punjabi

2005-01-01

22

Beta decay of highly charged ions  

NASA Astrophysics Data System (ADS)

Beta decay of highly charged ions has attracted much attention in recent years. An obvious motivation for this research is that stellar nucleosynthesis proceeds at high temperatures where the involved atoms are highly ionized. Another important reason is addressing decays of well-defined quantum-mechanical systems, such as one-electron ions where all interactions with other electrons are excluded. The largest modifications of nuclear half-lives with respect to neutral atoms have been observed in beta decay of highly charged ions. These studies can be performed solely at ion storage rings and ion traps, because there high atomic charge states can be preserved for extended periods of time (up to several hours). Currently, all experimental results available in this field originate from experiments at the heavy-ion complex GSI in Darmstadt. There, the fragment separator facility FRS allows the production and separation of exotic, highly charged nuclides, which can then be stored and investigated in the storage ring facility ESR. In this review, we present and discuss in particular two-body beta decays, namely bound-state beta decay and orbital electron capture. Although we focus on experiments conducted at GSI, we will also attempt to provide general requirements common to any other experiment in this context. Finally, we address challenging but not yet performed experiments and we give prospects for the new radioactive beam facilities, such as FAIR in Darmstadt, IMP in Lanzhou and RIKEN in Wako.

Litvinov, Yuri A.; Bosch, Fritz

2011-01-01

23

Deuterium-tritium TFTR plasmas in the high poloidal beta regime  

SciTech Connect

Deuterium-tritium plasmas with enhanced energy confinement and stability have been produced in the high poloidal beta, advanced tokamak regime in TFTR. Confinement enhancement H {triple_bond} {tau}{sub E}/{tau}{sub E ITER-89P} > 4 has been obtained in a limiter H-mode configuration at moderate plasma current I{sub p} = 0.85 {minus} 1.46 MA. By peaking the plasma current profile, {beta}{sub N dia} {triple_bond} 10{sup 8} < {beta}{sub t{perpendicular}} > aB{sub 0}/I{sub p} = 3 has been obtained in these plasma,s exceeding the {beta}{sub N} limit for TFTR plasmas with lower internal inductance, l{sub i}. Fusion power exceeding 6.7 MW with a fusion power gain Q{sub DT} = 0.22 has been produced with reduced alpha particle first orbit loss provided by the increased l{sub i}.

Sabbagh, S.A.; Mauel, M.E.; Navratil, G.A. [Columbia Univ., New York, NY (United States). Dept. of Applied Physics] [and others

1995-03-01

24

High-{beta} disruption in tokamaks  

SciTech Connect

Three dimensional MHD simulations of high-{beta} plasmas show that toroidally localized high-n ballooning modes can be driven unstable by the local pressure steepening which arises from the evolution of low-n modes. Nonlinearly, the high-n mode becomes even more localized and produces a strong local pressure bulge which destroys the flux surfaces resulting in a thermal quench. The flux surfaces then recover temporarily but now contain large magnetic islands. This scenario is supported by experimental data.

Park, W.; Fredrickson, E.D.; Janos, A. [and others

1995-07-01

25

(High beta tokamak research and plasma theory)  

SciTech Connect

Our activities on High Beta Tokamak Research during the past 12 months of the present budget period can be divided into four areas: completion of kink mode studies in HBT; completion of carbon impurity transport studies in HBT; design of HBT-EP; and construction of HBT-EP. Each of these is described briefly in the sections of this progress report.

Not Available

1990-01-01

26

The effect of wall loading limitations and choice of beta on the feasibility of advanced fuel fusion reactors  

Microsoft Academic Search

This paper investigates the effect of wall loading limitations and choice of plasma stability index beta on the feasibility of advanced fuel fusion reactors. Two new conceptual tools are introduced to facilitate this analysis: the effective reactivity, which includes all of the reaction-relevant parameters which determine the fusion power density; and the critical radius, which is the maximum allowable minor

J. R. Roth; H. C. Roland

1979-01-01

27

The effect of wall loading limitations and choice of beta on the feasibility of advanced fuel fusion reactors  

Microsoft Academic Search

This paper investigates the effect of wall loading limitations and choice of plasma stability index beta on the feasibility of advanced fuel fusion reactors. Two new conceptual tools are introduced to facilitate this analysis: the “effective reactivity,” which includes all of the reaction-relevant parameters that determine the fusion power density, and the “critical radius,” which is the maximum allowable minor

J. Reece Roth; Hall C. Roland

1981-01-01

28

Cloning of an integrin beta subunit exhibiting high homology with integrin beta 3 subunit.  

PubMed Central

cDNAs for another beta subunit of the integrin family were isolated with the aid of polymerase chain reaction and sequenced. The combined cDNA sequence is 3110 base pairs (bp) in size and has one long open reading frame of 2388 bp. The deduced amino acid sequence is similar to those of other integrin beta subunits but does not correspond to beta 1, beta 2, beta 3, or beta 4 subunits. This beta subunit is divided by a membrane-spanning domain into a large extracellular domain at the N-terminal side and a small intracellular domain at the C-terminal side. The extracellular domain has a cysteine-rich region that contains four repeats of 8-cysteine motifs. All 56 cysteine residues found in the extracellular domains of other mature beta subunits are present in this beta subunit. The beta subunit reported here has particularly high homology with the beta 3 subunit. The mRNA for the molecule is approximately 3.5 kbp in size and is expressed in various cell types. Other researchers have recently reported additional beta subunits that associate with the vitronectin receptor alpha subunit. The deduced amino acid sequence of this molecule contains the N-terminal partial amino acid sequence of one of these beta subunits, beta x. The beta subunit described herein seems to be identical to the beta x subunit and to function as the beta subunit of a vitronectin receptor. Images

Suzuki, S; Huang, Z S; Tanihara, H

1990-01-01

29

Numerical models for high beta magnetohydrodynamic flow  

SciTech Connect

The fundamentals of numerical magnetohydrodynamics for highly conducting, high-beta plasmas are outlined. The discussions emphasize the physical properties of the flow, and how elementary concepts in numerical analysis can be applied to the construction of finite difference approximations that capture these features. The linear and nonlinear stability of explicit and implicit differencing in time is examined, the origin and effect of numerical diffusion in the calculation of convective transport is described, and a technique for maintaining solenoidality in the magnetic field is developed. Many of the points are illustrated by numerical examples. The techniques described are applicable to the time-dependent, high-beta flows normally encountered in magnetically confined plasmas, plasma switches, and space and astrophysical plasmas. 40 refs.

Brackbill, J.U.

1987-01-01

30

High beta and confinement studies on TFTR  

SciTech Connect

A new regime of high poloidal beta operation in TFTR was developed in the course of the first two years of this project (9/25/89 to 9/24/91). Our proposal to continue this successful collaboration between Columbia University and the Massachusetts Institute of Technology with the Princeton Plasma Physics Laboratory for a three year period (9/25/91 to 9/24/94) to continue to investigate improved confinement and tokamak performance in high poloidal beta plasmas in TFTR through the DT phase of operation was approved by the DOE and this is a report of our progress during the first 9 month budget period of the three year grant (9/25/91 to 6/24/92). During the approved three year project period we plan to (1) extend and apply the low current, high QDD discharges to the operation of TFTR using Deuterium and Tritium plasma; (2) continue the analysis and plan experiments on high poloidal beta phenomena in TFTR including: stability properties, enhanced global confinement, local transport, bootstrap current, and divertor formation; (3) plan and carry out experiments on TFTR which attempt to elevate the central q to values > 2 where entry to the second stability regime is predicted to occur; and (4) collaborate on high beta experiments using bean-shaped plasmas with a stabilizing conducting shell in PBX-M. In the seven month period covered by this report we have made progress in each of these four areas through the submission of 4 TFTR Experimental Proposals and the partial execution of 3 of these using a total of 4.5 run days during the August 1991 to February 1992 run.

Navratil, G.A.; Bhattacharjee, A.; Iacono, R.; Mauel, M.E.; Sabbagh, S.A. (Columbia Univ., New York, NY (United States)); Kesner, J. (Massachusetts Inst. of Tech., Cambridge, MA (United States))

1992-01-01

31

High-beta stability of a toroidal plasma  

NASA Astrophysics Data System (ADS)

The high toroidal mode number ideal MHD ballooning mode is shown to stabilize again at large beta, in several sequences of numerical toroidal equilibria. Raising the q profile improves high-beta stability for equilibria with the same poloidal beta and flux surface geometry. A smaller aspect ratio enhances the stabilizing effect of raising the q profile and allows second stability to occur at smaller poloidal beta, though larger total beta. Present address: University of California, Lawrence Livermore Laboratories, Livermore, CA 94550, USA.

Sugiyama, L.; Mark, J. W.-K.

1981-07-01

32

Comparison and analysis of fusion algorithms of high resolution imagery  

NASA Astrophysics Data System (ADS)

The fusion techniques have been developed quickly in recent years and become an important remote sensing research topic. This paper systematically discusses the technique used in pixel level image fusion including IHS transform, YIQ transform, HLS transform, HSV transform, PCA transform, HPF transform and wavelet transform image fusion method. Then a fusion experiment of IKONOS image is made to compares the different merging methods from spectral quality and the spatial quality in order to choose the suitable method for the high resolution image.

Dong, Guangjun; Huang, Xiaobo; Dai, Chenguang

2008-03-01

33

Ballooning instability precursors to high {beta} disruptions  

SciTech Connect

Strongly ballooning modes have been found as precursors to high {beta} disruptions on TFTR. The modes are typically localized to a region spanning about 60{degree} in the toroidal direction. The toroidal localization is associated with lower frequency, global Magneto-Hydro-Dynamic (MHD) activity, typically an ideal n = 1 kink mode. They have moderate to high frequency (f = 10--20 f{sub rot}), implying toroidal mode numbers in the range n = 10--20. The growth rates for the modes are large, of order 10{sup 4}/sec.

Fredrickson, E.D.; McGuire, K.M.; Chang, Z.Y. [and others

1995-12-01

34

High temperature experiment for accelerator inertial fusion  

SciTech Connect

The High Temperature Experiment (HTE) is intended to produce temperatures of 50 to 100 eV in solid density targets driven by heavy ion beams from a multiple beam induction linac. The fundamental variables (particle species, energy, number of beamlets, current and pulse length) must be fixed to achieve the temperature at minimum cost, subject to criteria of technical feasibility and relevance to the development of a Fusion Driver. The conceptual design begins with an assumed (radiation-limited) target temperature and uses limitations due to particle range, beamlet perveance, and target disassembly to bound the allowable values of mass number (A) and energy (E). An accelerator model is then applied to determine the minimum length accelerator, which is a guide to total cost. The accelerator model takes into account limits on transportable charge, maximum gradient, core mass per linear meter, and head-to-tail momentum variation within a pulse.

Lee, E.P.

1985-05-01

35

The high sensitivity double beta spectrometer TGV  

NASA Astrophysics Data System (ADS)

A high sensitivity double beta spectrometer TGV (Telescope Germanium Vertical) has been developed. It is based on 16 HPGe detectors of volume 1200 × 6 mm3 each in the same cryostat. The TGV spectrometer was proposed for the study of ultrarare nuclear processes (e.g. 2???, 0???, 2?EC/EC). Details of the TGV spectrometer construction are described, the principles of background suppression, the results of Monte Carlo simulations and the results of test background measurements (in Dubna and Modane underground laboratory) are provided.

Briancon, Ch.; Brudanin, V. B.; Egorov, V. G.; Janout, Z.; Koní?ek, J.; Kovalík, A.; Kovalenko, V. E.; Kubašta, J.; Pospíšil, S.; Revenko, A. V.; Rukhadze, N. I.; Salamatin, A. V.; Sandukovsky, V. G.; Štekl, I.; Timkin, V. V.; Tsupko-Sitnikov, V. V.; Vorobel, V.; Vylov, Ts.

1996-02-01

36

Modular low aspect ratio-high beta torsatron  

DOEpatents

A fusion reactor device in which the toroidal magnetic field and at least a portion of the poloidal magnetic field are provided by a single set of modular coils. The coils are arranged on the surface of a low aspect ratio toroid in planes having the cylindrical coordinate relationship .phi.=.phi..sub.i +kz where k is a constant equal to each coil's pitch and .phi..sub.i is the toroidal angle at which the i'th coil intersects the z=o plane. The device may be described as a modular, high beta torsation whose screw symmetry is pointed along the systems major (z) axis. The toroid defined by the modular coils preferably has a racetrack minor cross section. When vertical field coils and preferably a toroidal plasma current are provided for magnetic field surface closure within the toroid, a vacuum magnetic field of racetrack shaped minor cross section with improved stability and beta valves is obtained.

Sheffield, George V. (Hopewell, NJ); Furth, Harold P. (Princeton, NJ)

1984-02-07

37

SUPPORT FOR HU CFRT SUMMER HIGH SCHOOL FUSION WORKSHOP  

Microsoft Academic Search

Nine summer fusion science research workshops for minority and female high school students were conducted at the Hampton University Center for Fusion Research and Training from 1996 to 2005. Each workshop was of the duration of eight weeks. In all 35 high school students were mentored. The students presented 28 contributed papers at the annual meetings of the American Physical

Alkesh Punjabi

2010-01-01

38

Development of high power ion sources for fusion (invited)  

Microsoft Academic Search

Recent progress and development activities regarding high power ion sources for fusion researches are reviewed. High power positive ion sources, which have progressed in the 1980s, played important roles in fusion research. Most of the ion sources developed for major neutral beam injection (NBI) systems are a large area magnetic multipole type with tungsten cathode, and produce tens of amperes

Y. Ohara

1998-01-01

39

High energy Gamow-Teller strenght in double beta decay  

Microsoft Academic Search

The contribution of high-lying intermediate states to the two-neutrino double beta decay is investigated in several approximations. Even though there is an appreciable beta- strength at high energy connecting the initial and intermediate nuclei, and a similar beta+ strength connecting the intermediate and final nuclei, we conclude that the contribution of high-lying states to the betabeta decay is strongly suppressed

Magda Ericson; Torleif Eric Oskar Ericson; Petr Vogel

1994-01-01

40

Progress toward high-gain laser fusion  

SciTech Connect

A 1985-1986 Review of the US inertial confinement fusion program by the National Academy of Sciences concluded that five more years might be required to obtain enough data to determine the future course of the program. Since then, data from the Nova laser and from the Halite/Centurion program have resolved most of the outstanding problems identified by the NAS review. In particular, we now believe that we can produce a sufficiently uniform target; that we can keep the energy content in hot electrons and high-energy photons low enough (/approximately/1--10% of drive energy, depending on target design) and achieve enough pulse-shaping accuracy (/approximately/10%, with a dynamic range of 100:1) to keep the fuel on a near-Fermi-degenerate adiabat; that we can produce an /approximately/100-Mbar pressure pulse of sufficient uniformity (/approximately/1%), and can we control hydrodynamic instabilities so that the mix of the pusher into the hot spot is low enough to permit marginal ignition. These results are sufficiently encouraging that the US Department of Energy is planning to complete a 10-MJ laboratory microfusion facility to demonstrate high-gain ICF in the laboratory within a decade. 22 refs., 1 fig.

Storm, E.

1988-09-28

41

High current injector for heavy ion fusion  

SciTech Connect

A 2 MV, 800 mA, K{sup +} injector for heavy ion fusion studies is under construction. This new injector is a one-beam version of the proposed 4-beam ILSE injector. A new 36-module MARX is being built to achieve a 5 {mu}s flat top. The high voltage generator is stiff (< 5k{Omega}) to minimize effects of beam-induced transients. A large ({approx} 7 in. diameter) curved hot alumina-silicate source emits a 1 {mu}s long beam pulse through a gridless extraction electrode, and the ions are accelerated to 1 MV in a diode configuration. Acceleration to 2 MV takes place in a set of electrostatic quadrupole (ESQ) units, arranged to simultaneously focus and accelerate the ion beam. Heavy shields and other protection devices have been built in to minimize risks of high voltage breakdown. Beam aberration effects through the ESQ have been studied extensively with theory, simulations, and scaled experiments. The design, simulations, experiments, and engineering of the ESQ injector will be presented.

Yu, S.; Eylon, S.; Chupp, W.W.

1993-05-01

42

Beta decay of highly charged ions  

NASA Astrophysics Data System (ADS)

A brief overview is presented in this paper on some experiments conducted at the Experimental Storage Ring (ESR) of GSI which addressed the ? decay of stored and cooled highly charged ions. Special emphasis is placed on the two-body beta decay of bare or few-electron ions: bound-state ?- decay (?b) and its time-mirrored counterpart, orbital electron capture. The former decay mode was detected experimentally 20 years ago at the ESR. The latter could be investigated there for the first time in detail for the simplest quantum systems: hydrogen- and helium-like atoms. The main results of these experiments will be presented. Also their impact on stellar nucleosynthesis, in particular the s-process, is discussed.

Bosch, F.; Atanasov, D. R.; Brandau, C.; Dillmann, I.; Dimopoulou, C.; Faestermann, T.; Geissel, H.; Hagmann, S.; Hillenbrand, P.-M.; Kienle, P.; Knöbel, R.; Kozhuharov, C.; Kurcewicz, J.; Lestinsky, M.; Litvinov, S. A.; Litvinov, Yu A.; Ma, X.; Nolden, F.; Ohtsubo, T.; Patyk, Z.; Reuschl, R.; Sanjari, M. S.; Scheidenberger, C.; Shubina, D.; Spillmann, U.; Steck, M.; Stöhlker, Th; Sun, B.; Trassinelli, M.; Trotsenko, S.; Tu, X. L.; Weick, H.; Winckler, N.; Winkler, M.; Winters, D. F. A.; Yamaguchi, T.; Yan, X. L.

2013-09-01

43

Thermostable beta-glycosidase-CBD fusion protein for biochemical analysis of cotton scouring efficiency.  

PubMed

Multidomain proteins for the biochemical analysis of the scouring efficiency of cotton fabrics were constructed by the fusion of a reporter moiety in the N-terminal and the cellulose binding domain (CBD) in the C-terminal. Based on the specific binding of the CBD of Cellulomonas fimi exoglucanase (Cex) to crystalline cellulose (Avicel), the reporter protein is guided to the cellulose fibers that are increasingly exposed as the scouring process proceeds. Among the tested reporter proteins, a thermostable beta-glycosidase (BglA) from Thermus caldophilus was found to be most appropriate, showing a higher applicability and stability than GFP, DsRed, or a tetrameric beta-glucuronidase (GUS) from Escherichia coli, which were precipitated more seriously during the expression and purification steps. When cotton fabrics with different scouring levels were treated with the BglA-CBD and incubated with X-Gal as the chromogenic substrate, an indigo color became visible within 2 h, and the color depth changed according to the conditions and extent of the scouring. PMID:18388460

Ha, Jae-Seok; Lee, Young-Mi; Choi, Su-Lim; Song, Jae Jun; Shin, Cheol-Soo; Kim, Ju-Hea; Lee, Seung-Goo

2008-03-01

44

Forming a 'perfectly' uniform shell of solid DT fusion fuel by the beta-layering process.  

National Technical Information Service (NTIS)

Optical measurements made with a high resolution CCD video camera show that the solid DT layer formed by the ''beta-layering'' process in an isothermal cylindrical bore of 2000 (mu)m diameter may meet the strict criteria for layer thickness uniformity req...

J. K. Hoffer L. R. Foreman E. R. Mapoles J. D. Simpson

1992-01-01

45

Initial high beta operation of the HBT-EP tokamak  

SciTech Connect

HBT-EP is a new research tokamak designed and built to investigate passive and active feedback techniques to control MHD instabilities. In particular, HBT-EP will be able to test techniques to control fast MHD instabilities occurring at high Troyon-normalized beta, [beta][sub N] [equivalent to] [beta]Ba/I[sub p][Tm/MA], since it is equipped with a thick, close-fitting, and adjustable conducting shell. The major goals of the initial operation of HBT-EP have been the achievement of high beta operation ([beta][sub N] [approximately]3) using only ohmic heating and the observation of MHD instabilities. By using a unique fast start-up technique, the authors have successfully achieved these goals. A variety of MHD phenomena were observed during the high beta operation of HBT-EP. At modest beta ([beta][sub N] [le] 2), discharges have been maintained for more than 10 msec, and these discharges exhibit saturated resistive instabilities. When [beta][sub N] approaches 3, major disruptions occur preceded by oscillating, growing precursors. During start-up, one or more minor disruptions are usually observed. A 1-D transport code has been used to simulate the evolution of the current profile, and these early minor instabilities are predicted to be double tearing modes. The simulation also reproduces the observed high beta operation when saturated neo-Alcator energy confinement scaling is assumed.

Sankar, M.K.V.; Eisner, E.; Garofalo, A.; Gates, D.; Ivers, T.H.; Kombargi, R.; Mauel, M.E.; Maurer, D.; Nadle, D.; Navratil, G.A.; Xiao, Q. (Columbia Univ., New York, NY (United States))

1993-09-01

46

Progress of High-Beta Experiments in Stellarator/Heliotron  

SciTech Connect

Recently, dramatic progress has been achieved in the study of helical systems with high-beta experiments. Discharges with more than 3% beta plasmas have been achieved in Large Helical Device (LHD) and Wendelstein 7-AS (W7-AS). Although magnetohydrodynamic (MHD) instabilities affect local pressure gradients, the global transport property does not seem to limit the achieved beta value in either device. We summarize the LHD high-beta properties in MHD stability, equilibrium, and transport, and we show the relationship between the experimentally achieved parameters and theoretical predictions. We contrast the LHD results with the W7-AS high-beta properties. In both devices, stationary discharges in the definitely MHD unstable region have not been observed. We mention the key issue for achievement of the beta values >5%.

Watanabe, Kiyomasa Y. [National Institute for Fusion Science (Japan); Weller, Arthur [Max-Planck-Institut fuer Plasmaphysik (Germany); Sakakibara, Satoru [National Institute for Fusion Science (Japan); Narushima, Yoshiro [National Institute for Fusion Science (Japan); Ohdachi, Satoshi [National Institute for Fusion Science (Japan); Narihara, Kazumichi [National Institute for Fusion Science (Japan); Tanaka, Kenji [National Institute for Fusion Science (Japan); Ida, Katsumi [National Institute for Fusion Science (Japan); Toi, Kazuo [National Institute for Fusion Science (Japan); Yamada, Hiroshi [National Institute for Fusion Science (Japan); Suzuki, Yasuhiro [Graduate School of Energy Science (Japan); Kaneko, Osamu [National Institute for Fusion Science (Japan)

2004-07-15

47

Progress Toward High-Gain Laser Fusion.  

National Technical Information Service (NTIS)

A 1985-1986 Review of the US inertial confinement fusion program by the National Academy of Sciences concluded that five more years might be required to obtain enough data to determine the future course of the program. Since then, data from the Nova laser...

E. Storm

1988-01-01

48

Materials integration issues for high performance fusion power systems.  

National Technical Information Service (NTIS)

One of the primary requirements for the development of fusion as an energy source is the qualification of materials for the frost wall/blanket system that will provide high performance and exhibit favorable safety and environmental features. Both economic...

D. L. Smith

1998-01-01

49

Progress toward fully noninductive, high beta conditions in DIII-D  

NASA Astrophysics Data System (ADS)

The DIII-D Advanced Tokamak (AT) program in the DIII-D tokamak [J. L. Luxon, Plasma Physics and Controlled Fusion Research, 1986, Vol. I (International Atomic Energy Agency, Vienna, 1987), p. 159] is aimed at developing a scientific basis for steady-state, high-performance operation in future devices. This requires simultaneously achieving 100% noninductive operation with high self-driven bootstrap current fraction and toroidal beta. Recent progress in this area includes demonstration of 100% noninductive conditions with toroidal beta, ?T=3.6%, normalized beta, ?N=3.5, and confinement factor, H89=2.4 with the plasma current driven completely by bootstrap, neutral beam current drive, and electron cyclotron current drive (ECCD). The equilibrium reconstructions indicate that the noninductive current profile is well aligned, with little inductively driven current remaining anywhere in the plasma. The current balance calculation improved with beam ion redistribution that was supported by recent fast ion diagnostic measurements. The duration of this state is limited by pressure profile evolution, leading to magnetohydrodynamic (MHD) instabilities after about 1 s or half of a current relaxation time (?CR). Stationary conditions are maintained in similar discharges (~90% noninductive), limited only by the 2 s duration (1?CR) of the present ECCD systems. By discussing parametric scans in a global parameter and profile databases, the need for low density and high beta are identified to achieve full noninductive operation and good current drive alignment. These experiments achieve the necessary fusion performance and bootstrap fraction to extrapolate to the fusion gain, Q=5 steady-state scenario in the International Thermonuclear Experimental Reactor (ITER) [R. Aymar et al., Fusion Energy Conference on Controlled Fusion and Plasma Physics, Sorrento, Italy (International Atomic Energy Agency, Vienna, 1987), paper IAEA-CN-77/OV-1]. The modeling tools that have been successfully employed to both plan and interpret the experiment are used to plan future DIII-D experiments with higher power and longer pulse ECCD and fast wave and co- and counterneutral beam injection in a pumped double-null configuration. The models predict our ability to control the current and pressure profiles to reach full noninductivity with increased beta, bootstrap fraction, and duration. The same modeling tools are applied to ITER, predicting favorable prospects for the success of the ITER steady-state scenario.

Murakami, M.; Wade, M. R.; Greenfield, C. M.; Luce, T. C.; Ferron, J. R.; John, H. E. St.; Deboo, J. C.; Heidbrink, W. W.; Luo, Y.; Makowski, M. A.; Osborne, T. H.; Petty, C. C.; Politzer, P. A.; Allen, S. L.; Austin, M. E.; Burrell, K. H.; Casper, T. A.; Doyle, E. J.; Garofalo, A. M.; Gohil, P.; Gorelov, I. A.; Groebner, R. J.; Hyatt, A. W.; Jayakumar, R. J.; Kajiwara, K.; Kessel, C. E.; Kinsey, J. E.; La Haye, R. J.; Lao, L. L.; Leonard, A. W.; Lohr, J.; Petrie, T. W.; Pinsker, R. I.; Prater, R.; Rhodes, T. L.; Sips, A. C. C.; Staebler, G. M.; Taylor, T. S.; Vanzeeland, M. A.; Wang, G.; West, W. P.; Zeng, L.; DIII-D Team

2006-05-01

50

Soluble fusion expression and characterization of human beta-defensin 3 using a novel approach.  

PubMed

Human ?-defensin 3 (DEFB103) is a recently identified small cysteine-rich cationic peptide expressed ubiquitously upon local microbial invasion. A number of accumulating evidences indicate that this peptide is involved in many biological processes, including microbicidal activities, chemoattraction, and immunomodulation. In this article, we describe a novel approach through which we performed the expression and purification of the recombinant DEFB103 peptide in Escherichia coli (E. coli) based on the pTWIN1 expression system. This approach does not introduce any extra residues to the peptide product, and also eliminates the requirement of removing the fusion tag by exogenous proteases. A high yield of 112 mg of soluble fusion DEFB103 was obtained in 1 liter of Luria-Bertani (LB) medium. By one-step affinity chromatography and on-column, auto-cleavage of the fusion tag, the mature DEFB103 peptide was produced with a yield of 30 mg/L LB. The purified DEFB103 peptide demonstrated strong antimicrobial activities against E. coli, S. aureus and C. albicans, which were representatives of Gram-negative and Gram-positive bacteria and fungi, respectively. Using this novel approach, we have successfully expressed and purified several human defensins with significant bioactivities. Our work may be helpful for structural and functional studies of other human defensins, and also for the production of human defensins. PMID:21605057

Dong, Jing; Yu, Heguo; Zhang, Yonglian; Diao, Hua; Lin, Donghai

2011-11-01

51

High-Frequency Gravitational Wave Induced Nuclear Fusion  

SciTech Connect

Nuclear fusion is a process in which nuclei, having a total initial mass, combine to produce a single nucleus, having a final mass less than the total initial mass. Below a given atomic number the process is exothermic; that is, since the final mass is less than the combined initial mass and the mass deficit is converted into energy by the nuclear fusion. On Earth nuclear fusion does not happen spontaneously because electrostatic barriers prevent the phenomenon. To induce controlled, industrial scale, nuclear fusion, only a few methods have been discovered that look promising, but net positive energy production is not yet possible because of low overall efficiency of the systems. In this paper we propose that an intense burst of High Frequency Gravitational Waves (HFGWs) could be focused or beamed to a target mass composed of appropriate fuel or target material to efficiently rearrange the atomic or nuclear structure of the target material with consequent nuclear fusion. Provided that efficient generation of HFGW can be technically achieved, the proposed fusion reactor could become a viable solution for the energy needs of mankind and alternatively a process for beaming energy to produce a source of fusion energy remotely - even inside solid materials.

Fontana, Giorgio [University of Trento, 38050 POVO (Italy); Baker, Robert M. L. Jr. [Transportation Sciences Corporation and GRAVWAVE LLC, 8123 Tuscany Avenue, Playa del Rey, California 90293 (United States)

2007-01-30

52

Furin cleavage of bacterial expressed glutathione-S-transferase-pro-transforming growth factor beta1 fusion protein in vitro.  

PubMed

To investigate the processing of transforming growth factor beta1 (TGFbeta1) pro-protein by furin protease we expressed a GST-pro-TGFbeta1 fusion protein in bacteria. Analysis of the furin digestion pattern revealed the liberation of 12.5 kDa TGFbeta1 monomers. There was no evidence for cleavage of an alternative furin site within the pro-protein. PMID:19594430

Kahle, N A; Joffroy, C; Popp, S L; Knabbe, C; Stope, M B

2010-04-01

53

Successful spinal fusion by E. coli-derived BMP-2-adsorbed porous beta-TCP granules: a pilot study.  

PubMed

Bone morphogenetic proteins (BMPs) were originally identified as osteoinductive proteins. With cloning of BMP genes, studies of BMPs and their clinical application have advanced. However, with increasing clinical applications, drug delivery systems and production costs have become more important issues. To address these issues, we asked whether E. coli-derived rhBMP-2 (E-BMP-2)-adsorbed porous beta-TCP granules could achieve posterolateral lumbar fusion in a rabbit model similar to autogenous bone grafts. Lumbar spinal fusion masses were evaluated by 3-D computed tomography, mechanical testing, and histological analyses 8 weeks after surgery. By these measures E-BMP-2-adsorbed beta-TCP granules achieved lumbar spinal fusion in dose-dependent fashion in a rabbit model as well as autogenous bone graft. Our preliminary findings suggest E-BMP-2-adsorbed porous beta-TCP could be a novel, effective alternative to autogenous bone grafting for generating new bone and promoting regenerative repair of bone, and potentially utilizable in the clinical setting for treating spinal disorders. PMID:19582526

Dohzono, Sho; Imai, Yuuki; Nakamura, Hiroaki; Wakitani, Shigeyuki; Takaoka, Kunio

2009-07-07

54

Fusion  

Microsoft Academic Search

The book abounds with fascinating anecdotes about fusion's rocky path: the spurious claim by Argentine dictator Juan Peron in 1951 that his country had built a working fusion reactor, the rush by the United States to drop secrecy and publicize its fusion work as a propaganda offensive after the Russian success with Sputnik; the fortune Penthouse magazine publisher Bob Guccione

Robin Herman

1990-01-01

55

High energy photocathodes for laser fusion diagnostics  

SciTech Connect

Laser fusion experiments at the National Ignition Facility require time-resolved x-ray images of the ignition target self-emission. The photon energies are expected to be greater than 10 keV. Photoemission quantum yield measurement data and photoelectron energy spectrum data are presently unavailable in this photon energy range, but are essential in the design of x-ray imaging diagnostics. We developed an apparatus to measure the quantum efficiency of primary and secondary photoelectron emission and to estimate the energy spectrum of the secondary photoelectrons. The apparatus has been tested using photon energies less than 10 keV to allow comparisons with prior work. A method for preparing photocathodes with geometrically enhanced photoefficiency has been developed.

Halvorson, C.; Houck, T.; Macphee, A.; Opachich, Y. P.; Lahowe, D.; Copsey, B. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

2010-10-15

56

High energy photocathodes for laser fusion diagnostics.  

PubMed

Laser fusion experiments at the National Ignition Facility require time-resolved x-ray images of the ignition target self-emission. The photon energies are expected to be greater than 10 keV. Photoemission quantum yield measurement data and photoelectron energy spectrum data are presently unavailable in this photon energy range, but are essential in the design of x-ray imaging diagnostics. We developed an apparatus to measure the quantum efficiency of primary and secondary photoelectron emission and to estimate the energy spectrum of the secondary photoelectrons. The apparatus has been tested using photon energies less than 10 keV to allow comparisons with prior work. A method for preparing photocathodes with geometrically enhanced photoefficiency has been developed. PMID:21034008

Halvorson, C; Houck, T; Macphee, A; Opachich, Y P; Lahowe, D; Copsey, B

2010-10-01

57

High energy photocathodes for laser fusion diagnostics  

NASA Astrophysics Data System (ADS)

Laser fusion experiments at the National Ignition Facility require time-resolved x-ray images of the ignition target self-emission. The photon energies are expected to be greater than 10 keV. Photoemission quantum yield measurement data and photoelectron energy spectrum data are presently unavailable in this photon energy range, but are essential in the design of x-ray imaging diagnostics. We developed an apparatus to measure the quantum efficiency of primary and secondary photoelectron emission and to estimate the energy spectrum of the secondary photoelectrons. The apparatus has been tested using photon energies less than 10 keV to allow comparisons with prior work. A method for preparing photocathodes with geometrically enhanced photoefficiency has been developed.

Halvorson, C.; Houck, T.; Macphee, A.; Opachich, Y. P.; Lahowe, D.; Copsey, B.

2010-10-01

58

Formation of Ultra High Beta Spherical Tokamak by Use of Merging Spheromak Plasmas  

NASA Astrophysics Data System (ADS)

We formed ultra-high beta spherical tokamak plasmas using both of two spherical plasma merging and ramp-up of external toroidal field.footnotetextY. Ono et al. Nucl. Fusion 43, 789, (2003). The merging and reconnection heats ions significantly during magnetic reconnection in TS-3 experiments. The maximum ion temperature Ti˜ 250 eV is obtained in two merging spheromaks with counter-helicity and Ti˜ 120 eV in those with co-helicity. While the reconnection heating decreases with the external guide toroidal field Bt, the confinement time of toroidal plasma tends to increase with external Bt. In order to confine the maximum ion thermal energy, we applied external Bt to merging low-q plasmas such as spheromaks with co- and counter-helicity after completion of reconnection, transforming the high-beta low-q toroid to an ultra high-beta ST in TS-3^[1] and TS-4. This transformation increases the life times of low-q toroids by fact 2-3. It is noted that the high-beta ST has an absolute minimum B profile with deep magnetic well. With increasing the ramp-up speed of external Bt, the magnetic well increases, but stays longer in low-q state unstable to MHD modes.

Ito, Taichi; Toru, II; Inomoto, Michiaki; Ono, Yasushi

2012-10-01

59

High poloidal beta equilibria in TFTR limited by a natural inboard poloidal field null  

SciTech Connect

Recent operation of the Tokamak Fusion Test Reactor TFTR, has produced plasma equilibria with values of {Lambda} {triple bond} {beta}{sub p eq} + l{sub i}/2 as large as 7, {epsilon}{beta}{sub p dia} {triple bond} 2{mu}{sub 0}{epsilon}/{much lt}B{sub p}{much gt}{sup 2} as large as 1.6, and Troyon normalized diamagnetic beta, {beta}{sub N dia} {triple bond} 10{sup 8}<{beta}{sub t}{perpendicular}>aB{sub 0}/I{sub p} as large as 4.7. When {epsilon}{beta}{sub p dia} {approx gt} 1.25, a separatrix entered the vacuum chamber, producing a naturally diverted discharge which was sustained for many energy confinement times, {tau}{sub E}. The largest values of {epsilon}{beta}{sub p} and plasma stored energy were obtained when the plasma current was ramped down prior to neutral beam injection. The measured peak ion and electron temperatures were as large as 24 keV and 8.5 keV, respectively. Plasma stored energy in excess of 2.5 MJ and {tau}{sub E} greater than 130 msec were obtained. Confinement times of greater than 3 times that expected from L-mode predictions have been achieved. The fusion power gain. Q{sub DD}, reached a values of 1.3 {times} 10{sup {minus}3} in a discharge with I{sub p} = 1 MA and {epsilon}{beta}{sub p dia} = 0.85. A large, sustained negative loop voltage during the steady state portion of the discharge indicates that a substantial non-inductive component of I{sub p} exists in these plasmas. Transport code analysis indicates that the bootstrap current constitutes up to 65% of I{sup p}. Magnetohydrodynamic (MHD) ballooning stability analysis shows that while these plasmas are near, or at the {beta}{sub p} limit, the pressure gradient in the plasma core is in the first region of stability to high-n modes. 24 refs., 10 figs.

Sabbagh, S.A.; Gross, R.A.; Mauel, M.E.; Navratil, G.A. (Columbia Univ., New York, NY (United States). Dept. of Applied Physics); Bell, M.G.; Bell, R.; Bitter, M.; Bretz, N.L.; Budny, R.V.; Bush, C.E.; Chance, M.S.; Efthimion, P.C.; Fredrickson, E.D.; Hatcher, R.; Hawryluk, R.J.; Hirshman, S.P.; Janos, A.C.; Jardin, S.C.; Jassby, D.L.; Manickam, J.; McCune, D.C.; McGuire, K.M.; Medley, S.S.; Mueller, D.; Nagayama, Y.; Ow

1991-07-01

60

Environmentally Assisted Cracking of High Strength Beta Titanium Alloys.  

National Technical Information Service (NTIS)

The objective of this integrated research program is to define the conditions under which high strength Beta-titanium alloys resist environmentally assisted cracking (EAC) in marine environments. Specific goals are to: (1) characterize EAC for metallurgic...

1993-01-01

61

Materials integration issues for high performance fusion power systems.  

SciTech Connect

One of the primary requirements for the development of fusion as an energy source is the qualification of materials for the frost wall/blanket system that will provide high performance and exhibit favorable safety and environmental features. Both economic competitiveness and the environmental attractiveness of fusion will be strongly influenced by the materials constraints. A key aspect is the development of a compatible combination of materials for the various functions of structure, tritium breeding, coolant, neutron multiplication and other special requirements for a specific system. This paper presents an overview of key materials integration issues for high performance fusion power systems. Issues such as: chemical compatibility of structure and coolant, hydrogen/tritium interactions with the plasma facing/structure/breeder materials, thermomechanical constraints associated with coolant/structure, thermal-hydraulic requirements, and safety/environmental considerations from a systems viewpoint are presented. The major materials interactions for leading blanket concepts are discussed.

Smith, D. L.

1998-01-14

62

SUPPORT FOR HU CFRT SUMMER HIGH SCHOOL FUSION WORKSHOP  

SciTech Connect

Nine summer fusion science research workshops for minority and female high school students were conducted at the Hampton University Center for Fusion Research and Training from 1996 to 2005. Each workshop was of the duration of eight weeks. In all 35 high school students were mentored. The students presented 28 contributed papers at the annual meetings of the American Physical Society Division of Plasma Physics. These contributed papers were very well received by the plasma physics and fusion science research community. The students won a number of prestigious local, state, and national honors, awards, prizes, and scholarships. The notable among these are the two regional finalist positions in the 1999 Siemens-Westinghouse Science and Technology Competitions; 1st Place U.S. Army Award, 2006; 1st Place U.S. Naval Science Award, 2006; Yale Science and Engineering Association Best 11th Grade Project, 2006; Society of Physics Students Book Award, 2006; APS Corporate Minority Scholarship and others. This workshop program conducted by the HU CFRT has been an exemplary success, and served the minority and female students exceptionally fruitfully. The Summer High School Fusion Science Workshop is an immensely successful outreach activity conducted by the HU CFRT. In this workshop, we train, motivate, and provide high quality research experiences to young and talented high school scholars with emphasis on under-represented minorities and female students in fusion science and related areas. The purpose of this workshop is to expose minority and female students to the excitement of research in science at an early stage in their academic lives. It is our hope that this may lead the high school students to pursue higher education and careers in physical sciences, mathematics, and perhaps in fusion science. To our knowledge, this workshop is the first and only one to date, of fusion science for under-represented minorities and female high school students at an HBCU. The faculty researchers in the HU CFRT mentor the students during summers. Mentors spend a considerable amount of time and efforts in training, teaching, guiding and supervising research projects. The HU CFRT has so far conducted nine workshops during the summers of 1996-2000 and 2002-2005. The first workshop was conducted in summer 1996. Students for the workshop are chosen from a national pool of exceptionally talented high school rising seniors/juniors. To our knowledge, most of these students have gone on to prestigious universities such as Duke University, John Hopkins University, CalTech, UCLA, Hampton University, etc. after completing their high school. For instance, Tiffany Fisher, participant of the 1996 summer workshop completed her BS in Mathematics at Hampton University in May 2001. She then went on to Wake Forest University at Winston-Salem, North Carolina to pursue graduate studies. Anshul Haldipur, participant of the 1999 summer workshop, began his undergraduate studies at Duke University in 2000. Christina Nguyen and Ilissa Martinez, participants of the 2000 summer workshop, are pursuing their undergraduate degrees at the UCLA and Florida State University respectively. The organizing committee of the APS DPP annual meeting invited Dr. Punjabi to deliver an invited talk on training the next generation of fusion scientists and engineers at the 2005 APS DPP meeting in Denver, CO. The organizing committee distributed a special flier with the Bulletin to highlight this invited talk and another talk on education as well the expo. This has given wide publicity and recognition to our workshops and Hampton University. Prof. Punjabi's talk: 'LI2 2: Training the next generation of fusion scientists and engineers: summer high school fusion science workshop, Bull. Amer. Phys. Soc. 50, 221 (2005)' was very well-received. He talked about HU education and outreach initiative and the HU CFRT Summer High School Workshop. The audience had a considerable number of questions about our workshops and the High School to PhD Pipeline in fusion science. Professor William Mathews of

Alkesh Punjabi

2010-02-09

63

High current ion beam RF acceleration and perspectives for an inertial fusion driver  

NASA Astrophysics Data System (ADS)

The actual situation with respect to the use of an RF linac driver for heavy ion inertial fusion (HIF) is discussed. At present, there is no high current heavy ion linac under construction. However, in the course of linac projects for e[minus sign], p, d, or highly charged ions several developments were made, which may have some impact on the design of a HIF driver. Medium- and low-[beta] superconducting structures suited for pulsed high current beam operation are actually designed and investigated at several laboratories. A superconducting 40 MeV, 125 mA cw linac for deuteron acceleration is designed for the Inertial Fusion Material Irradiation Facility (IFMIF). The Institute for Applied Physics (IAP) is developing a superconducting 350-MHz, 19-cell prototype CH-cavity for [beta] = 0.1. The prototype cavity will be ready for tests in 2004. A superconducting main HIF driver linac would considerably reduce the power losses. Moreover, it would allow for an efficient linac operation at a higher duty factor.

Ratzinger, U.; Liebermann, H.; Meusel, O.; Podlech, H.; Tiede, R.; Barth, W.; Vinzenz, W.

2003-10-01

64

Anterior cervical fusion with a bio-resorbable composite cage (beta TCP-PLLA): clinical and radiological results from a prospective study on 20 patients.  

PubMed

A resorbable composite material (40% PLLA and 60% beta TCP) with a high breaking strength and capacity to withstand plastic and elastic strain has been developed for cervical interbody fusion. This is a prospective study to evaluate clinical and radiological results of 20 patients implanted with 27 cages (mean follow-up, 27 months). Clinical (neck disability index, VAS, neurological evaluation) and radiological (anteroposterior, lateral, bending X-rays) data were assessed before and after surgery. At the end of the study, CT scan was performed to evaluate fusion, resorption of the cage and density of the new tissue substituting the cage. The mean patient age was 50.3 years (range, 18-79 years). The average improvement was 55% for neck pain, 83% for arm pain and 65% for NDI, with 85% good or excellent results at final outcomes. Radiologically, lordosis was significantly improved (mean gain of 5.4 degrees and 3.7 degrees for overall and segmental lordosis, respectively). This correction was conserved in 95% of cases. Fusion was obtained in 96% (CT evaluation). Resorption was started in all cases and completed in an average of 36 months after surgery. The mean density of tissue substituting the cage was 659 UH with a range, of 455-911 UH (compatible with bone nature). Over time, the amount of bony tissue increased and the graft remodelled with an increase in density value. This demonstrates a biological activity and changing bone mineral content of this tissue. The new composite cage under investigation provides long-term fusion without loss of correction or inflammatory reaction. The ceramic block guarantees the maintenance of the disc height and its slow resorption allows long-term fusion and stability with good and reliable clinical and radiological outcomes. PMID:19533180

Debusscher, F; Aunoble, S; Alsawad, Y; Clement, D; Le Huec, Jean-Charles

2009-06-17

65

Anterior cervical fusion with a bio-resorbable composite cage (beta TCP-PLLA): clinical and radiological results from a prospective study on 20 patients  

PubMed Central

A resorbable composite material (40% PLLA and 60% beta TCP) with a high breaking strength and capacity to withstand plastic and elastic strain has been developed for cervical interbody fusion. This is a prospective study to evaluate clinical and radiological results of 20 patients implanted with 27 cages (mean follow-up, 27 months). Clinical (neck disability index, VAS, neurological evaluation) and radiological (anteroposterior, lateral, bending X-rays) data were assessed before and after surgery. At the end of the study, CT scan was performed to evaluate fusion, resorption of the cage and density of the new tissue substituting the cage. The mean patient age was 50.3 years (range, 18–79 years). The average improvement was 55% for neck pain, 83% for arm pain and 65% for NDI, with 85% good or excellent results at final outcomes. Radiologically, lordosis was significantly improved (mean gain of 5.4° and 3.7° for overall and segmental lordosis, respectively). This correction was conserved in 95% of cases. Fusion was obtained in 96% (CT evaluation). Resorption was started in all cases and completed in an average of 36 months after surgery. The mean density of tissue substituting the cage was 659 UH with a range, of 455–911 UH (compatible with bone nature). Over time, the amount of bony tissue increased and the graft remodelled with an increase in density value. This demonstrates a biological activity and changing bone mineral content of this tissue. The new composite cage under investigation provides long-term fusion without loss of correction or inflammatory reaction. The ceramic block guarantees the maintenance of the disc height and its slow resorption allows long-term fusion and stability with good and reliable clinical and radiological outcomes.

Debusscher, F.; Aunoble, S.; Alsawad, Y.; Clement, D.

2009-01-01

66

HYFIRE - Fusion-high temperature electrolysis system  

Microsoft Academic Search

HYFIRE is the comprehensive conceptual design study of a commercial tokamak reactor, high-temperature electrolysis system. Particular emphasis is placed on the adaptability of the STARFIRE power reactor to a synfuel application. The HYFIRE blanket must perform three functions: (1) provide high-temperature (about 1400 C) process steam at moderate pressures (10-30 atm) to the high-temperature electrolysis (HTE) units, (2) provide high-temperature

J. A. Fillo; J. R. Powell; M. Steinberg; R. Benenati; V.-D. Dang; F. Horn; H. Isaacs; O. Lazareth; H. Makowitz; J. Usher

1980-01-01

67

A high-power laser fusion facility for Europe  

Microsoft Academic Search

Unprecedented sums of money are being committed to fusion research facilities around the world, yet there is a distinct danger that key opportunities for performing fundamental and applied research will be missed. A dedicated civilian high-power laser facility is needed to fill this breach.

Mike Dunne

2006-01-01

68

Hierarchical High Level Information Fusion (H2LIFT).  

National Technical Information Service (NTIS)

The primary objective of this effort was the progression of Level 2/3 fusion of informational content to obtain an advanced multi-intelligent system for hierarchical high-level decision making processes. The goal was to develop an information integration ...

A. Crassidis A. Stotz J. Crassidis M. Sudit R. Nagi

2008-01-01

69

Access to sustained high-beta with internal transport barrier and negative central magnetic shear in DIII-D  

SciTech Connect

High values of normalized {beta} ({beta}{sub N}{approx}4) and safety factor (q{sub min}{approx}2) have been sustained simultaneously for {approx}2 s in DIII-D [J.L. Luxon, Nucl. Fusion 42, 64 (2002)], suggesting a possible path to high fusion performance, steady-state tokamak scenarios with a large fraction of bootstrap current. The combination of internal transport barrier and negative central magnetic shear at high {beta} results in high confinement (H{sub 89P}>2.5) and large bootstrap current fraction (f{sub BS}>60%) with good alignment. Previously, stability limits in plasmas with core transport barriers have been observed at moderate values of {beta}{sub N} (<3) because of the pressure peaking which normally develops from improved core confinement. In recent DIII-D experiments, the internal transport barrier is clearly observed in the electron density and in the ion temperature and rotation profiles at {rho}{approx}0.5 but not in the electron temperature profile, which is very broad. The misalignment of T{sub i} and T{sub e} gradients may help to avoid a large local pressure gradient. Furthermore, at low internal inductance {approx}0.6, the current density gradients are close to the vessel and the ideal kink modes are strongly wall-coupled. Simultaneous feedback control of both external and internal sets of n=1 magnetic coils was used to maintain optimal error field correction and resistive wall mode stabilization, allowing operation above the free-boundary {beta} limit. Large particle orbits at high safety factor in the core help to broaden both the pressure and the beam-driven current profiles, favorable for steady-state operation. At plasma current flat top and {beta}{approx}5%, a noninductive current fraction of {approx}100% has been observed. Stability modeling shows the possibility for operation up to the ideal-wall limit at {beta}{approx}6%.

Garofalo, A.M.; Reimerdes, H. [Columbia University, New York, New York 10027 (United States); Doyle, E.J. [University of California, Los Angeles, California 90095 (United States); Ferron, J.R.; Greenfield, C.M.; Groebner, R.J.; Hyatt, A.W.; Jackson, G.L.; La Haye, R.J.; Osborne, T.H.; Petty, C.C.; Politzer, P.A.; Scoville, J.T.; St John, H.E.; Strait, E.J.; Turnbull, A.D.; Wade, M.R. [General Atomics, P.O. Box 85608, San Diego, California 92186 (United States); Jayakumar, R.J. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Kinsey, J.E. [Lehigh University, Bethlehem, Pennsylvania 18015 (United States); McKee, G.R. [University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)] (and others)

2006-05-15

70

Wall stabilization of high beta plasmas in DIII-D  

SciTech Connect

Detailed analysis of recent high beta discharges in the DIII-D tokamak demonstrates that the resistive vacuum vessel can provide stabilization of low n magnetohydrodynamic (MHD) modes. The experimental beta values reaching up to {beta}{sub T} = 12.6% are more than 30% larger than the maximum stable beta calculated with no wall stabilization. Plasma rotation is essential for stabilization. When the plasma rotation slows sufficiently, unstable modes with the characteristics of the predicted {open_quotes}resistive wall{close_quotes} mode are observed. Through slowing of the plasma rotation between the q = 2 and q = 3 surfaces with the application of a non-axisymmetric field, the authors have determined that the rotation at the outer rational surfaces is most important, and that the critical rotation frequency is of the order of {Omega}/2{pi} = 1 kHz.

Taylor, T.S.; Strait, E.J.; Lao, L.L.; Turnbull, A.D.; Burrell, K.H.; Chu, M.S.; Ferron, J.R.; Groebner, R.J.; La Haye, R.J. [General Atomics, San Diego, CA (United States); Mauel, M. [Columbia Univ., New York, NY (United States)] [and others

1995-02-01

71

X-1: The challenge of high fusion yield  

SciTech Connect

In the past three years, tremendous strides have been made in x-ray production using high-current z-pinches. Today, the x-ray energy and power output of the Z accelerator (formerly PBFA II) is the largest available in the laboratory. These z-pinch x-ray sources have great potential to drive high-yield inertial confinement fusion (ICF) reactions at affordable cost if several challenging technical problems can be overcome. Technical challenges in three key areas are discussed in this paper: (1) the design of a target for high yield, (2) the development of a suitable pulsed power driver, and (3) the design of a target chamber capable of containing the high fusion yield.

Cook, D.L.; Ramirez, J.J.; Raglin, P.S. [and others

1998-06-01

72

Physics Basis for High-Beta, Low-Aspect-Ratio Stellarator Experiments  

SciTech Connect

High-beta, low-aspect-ratio (compact) stellarators are promising solutions to the problem of developing a magnetic plasma configuration for magnetic fusion power plants that can be sustained in steady-state without disrupting. These concepts combine features of stellarators and advanced tokamaks and have aspect ratios similar to those of tokamaks (2-4). They are based on computed plasma configurations that are shaped in three dimensions to provide desired stability and transport properties. Experiments are planned as part of a program to develop this concept. A beta = 4% quasi-axisymmetric plasma configuration has been evaluated for the National Compact Stellarator Experiment (NCSX). It has a substantial bootstrap current and is shaped to stabilize ballooning, external kink, vertical, and neoclassical tearing modes without feedback or close-fitting conductors. Quasi-omnigeneous plasma configurations stable to ballooning modes at beta = 4% have been evaluated for the Quasi-Omnigeneous Stellarator (QOS) experiment. These equilibria have relatively low bootstrap currents and are insensitive to changes in beta. Coil configurations have been calculated that reconstruct these plasma configurations, preserving their important physics properties. Theory- and experiment-based confinement analyses are used to evaluate the technical capabilities needed to reach target plasma conditions. The physics basis for these complementary experiments is described.

A. Brooks; A.H. Reiman; G.H. Neilson; M.C. Zarnstorff; et al

1999-11-01

73

Forming a ``perfectly`` uniform shell of solid DT fusion fuel by the beta-layering process  

SciTech Connect

Optical measurements made with a high resolution CCD video camera show that the solid DT layer formed by the ``beta-layering`` process in an isothermal cylindrical bore of 2000 {mu}m diameter may meet the strict criteria for layer thickness uniformity required by implosion considerations ({approximately} 1% of the average layer thickness). Measurements are reported on preliminary experiments in which a 75 {mu}m thick solid layer was formed. Although the solid DT layer on the bore equilibrated with the expected rate constant of {approximately} 30 minutes, the layers on the optical windows were not optically smooth after more than 16 hours, leading to slight optical aberrations in the final image.

Hoffer, J.K.; Foreman, L.R. [Los Alamos National Lab., NM (United States); Mapoles, E.R. [Lawrence Livermore National Lab., CA (United States); Simpson, J.D. [General Atomics, San Diego, CA (United States)

1992-09-01

74

Forming a perfectly'' uniform shell of solid DT fusion fuel by the beta-layering process  

SciTech Connect

Optical measurements made with a high resolution CCD video camera show that the solid DT layer formed by the beta-layering'' process in an isothermal cylindrical bore of 2000 {mu}m diameter may meet the strict criteria for layer thickness uniformity required by implosion considerations ({approximately} 1% of the average layer thickness). Measurements are reported on preliminary experiments in which a 75 {mu}m thick solid layer was formed. Although the solid DT layer on the bore equilibrated with the expected rate constant of {approximately} 30 minutes, the layers on the optical windows were not optically smooth after more than 16 hours, leading to slight optical aberrations in the final image.

Hoffer, J.K.; Foreman, L.R. (Los Alamos National Lab., NM (United States)); Mapoles, E.R. (Lawrence Livermore National Lab., CA (United States)); Simpson, J.D. (General Atomics, San Diego, CA (United States))

1992-01-01

75

High power CW klystrons for fusion experiments  

Microsoft Academic Search

On TORE SUPRA (TS) located in Cadarache, the Lower Hybrid Current Drive (LHCD) 3.7 GHz system is being upgraded* in the frame of the CIMES project. Since the end of 2001, several technological components have been under manufacturing or have been installed. Particularly, a new high power CW klystron has been successfully developed and tested at Thales Electron Devices (TED)

A. Beunas; F. Kazarian

2008-01-01

76

Fusion  

NASA Astrophysics Data System (ADS)

The book abounds with fascinating anecdotes about fusion's rocky path: the spurious claim by Argentine dictator Juan Peron in 1951 that his country had built a working fusion reactor, the rush by the United States to drop secrecy and publicize its fusion work as a propaganda offensive after the Russian success with Sputnik; the fortune Penthouse magazine publisher Bob Guccione sank into an unconventional fusion device, the skepticism that met an assertion by two University of Utah chemists in 1989 that they had created "cold fusion" in a bottle. Aimed at a general audience, the book describes the scientific basis of controlled fusion--the fusing of atomic nuclei, under conditions hotter than the sun, to release energy. Using personal recollections of scientists involved, it traces the history of this little-known international race that began during the Cold War in secret laboratories in the United States, Great Britain and the Soviet Union, and evolved into an astonishingly open collaboration between East and West.

Herman, Robin

1990-10-01

77

MHD activity and energy loss during beta saturation and collapse at high beta poloidal in PBX  

SciTech Connect

High-..beta.. experiments, in medium to high-q tokamak plasmas, exhibit a temporal ..beta.. saturation and collapse. This behavior has been attributed to ballooning, ideal kink, or tearing modes. In PBX, a unique diagnostic capability allowed studies of the relation between MHD and energy loss for neutral-beam-heated (<6 MW), mildly indented (10 to 15%), nearly steady I/sub p/ discharges that approached the Troyon-Gruber limit. Under these conditions, correlations between MHD activity and energy losses have shown that the latter can be almost fully accounted for by various long wavelength MHD instabilities and that there is no need to invoke high-n ballooning modes in PBX. 6 refs., 4 figs.

Kugel, H.W.; Sesnic, S.; Bol, K.; Chance, M.; Fishman, H.; Fonck, R.; Gammel, G.; Kaita, R.; Kaye, S.; LeBlanc, B.

1987-10-01

78

A silicon array detector for high-energy betas  

NASA Astrophysics Data System (ADS)

The detection of significant levels of certain gamma and beta emitting isotopes could allow on-site Inspection teams working under the Comprehensive Test Ban Treaty to localize probable vent and fissure locations. Thus, sophisticated drilling and radionuclide measurements could then be made more effectively allowing for a higher probability of correctly identifying a nuclear event. In order to address this need we have developed a silicon array coupled with a Nal for detecting gammas, high-energy betas, and beta-gamma coincidences. The pursuit of this detection method is now viable since large-area, high-purity silicon wafers are now commercially available making this layered, large-area technique technically and economically feasible. We have designed, constructed, and tested a prototype detector system and we will present out initial test data.

Bowyer, S. M.; Bowyer, T. W.

1999-02-01

79

New physics directions for heavy-ion-driven high energy density physics and fusion energy  

Microsoft Academic Search

The heavy ion fusion program is shifting research emphasis towards a key scientific question of fundamental importance to both high energy density physics and inertial fusion energy: How can heavy ion beams be compressed to the high intensities required for creating high energy density matter and fusion ignition conditions? The primary scientific challenge is to compress intense ion beams in

B. Grant Logan

2004-01-01

80

Fusion blanket for high-efficiency power cycles  

SciTech Connect

The efficiencies of blankets for fusion reactors are usually in the range of 30 to 40%, limited by the operating temperature (500/sup 0/C) of conventional structural materials such as stainless steels. In this project two-zone blankets are proposed; these blankets consist of a low-temperature shell surrounding a high-temperature interior zone. A survey of nucleonics and thermal hydraulic parameters has led to a reference blanket design consisting of a water-cooled stainless steel shell around a BeO, ZrO/sub 2/ interior (cooled by Ar) utilizing Li/sub 2/O for tritium breeding. In this design, approx. 60% of the fusion energy is deposited in the high-temperature interior. The maximum Ar temperature is 2230/sup 0/C leading to an overall efficiency estimate of 55 to 60% for this reference case.

Usher, J.L.; Powell, J.R.; Fillo, J.A.; Horn, F.L.; Lazareth, O.W.; Taussig, R.

1980-01-01

81

Applications of high-speed dust injection to magnetic fusion  

SciTech Connect

It is now an established fact that a significant amount of dust is produced in magnetic fusion devices due to plasma-wall interactions. Dust inventory must be controlled, in particular for the next-generation steady-state fusion machines like ITER, as it can pose significant safety hazards and degrade performance. Safety concerns are due to tritium retention, dust radioactivity, toxicity, and flammability. Performance concerns include high-Z impurities carried by dust to the fusion core that can reduce plasma temperature and may even induce sudden termination of the plasma. We have recognized that dust transport, dust-plasma interactions in magnetic fusion devices can be effectively studied experimentally by injection of dust with known properties into fusion plasmas. Other applications of injected dust include diagnosis of fusion plasmas and edge localized mode (ELM)'s pacing. In diagnostic applications, dust can be regarded as a source of transient neutrals before complete ionization. ELM's pacing is a promising scheme to prevent disruptions and type I ELM's that can cause catastrophic damage to fusion machines. Different implementation schemes are available depending on applications of dust injection. One of the simplest dust injection schemes is through gravitational acceleration of dust in vacuum. Experiments at Los Alamos and Princeton will be described, both of which use piezoelectric shakers to deliver dust to plasma. In Princeton experiments, spherical particles (40 micron) have been dropped in a systematic and reproducible manner using a computer-controlled piezoelectric bending actuator operating at an acoustic (0,2) resonance. The circular actuator was constructed with a 2.5 mm diameter central hole. At resonance ({approx} 2 kHz) an applied sinusoidal voltage has been used to control the flux of particles exiting the hole. A simple screw throttle located {approx}1mm above the hole has been used to set the magnitude of the flux achieved for a given voltage. Particle fluxes ranging from a few tens of particle per second up to thousands of particles per second have been achieved using this simple device. To achieve higher dust injection speed, another key consideration is how to accelerate dust at controlled amount. In addition to gravity, other possible acceleration mechanisms include electrostatic, electromagnetic, gas-dragged, plasma-dragged, and laser-ablation-based acceleration. Features and limitations of the different acceleration methods will be discussed. We will also describe laboratory experiments on dust acceleration.

Wang, Zhehui [Los Alamos National Laboratory; Li, Yangfang [Max Planck Institute for Extraterrestrial Physics, Germany

2012-08-08

82

Design issues for a laboratory high gain fusion facility  

SciTech Connect

In an inertial fusion laboratory high gain facility, experiments will be carried out with up to 1000 MJ of thermonuclear yield. The experiment area of such a facility will include many systems and structures that will have to operate successfully in the difficult environment created by the sudden large energy release. This paper estimates many of the nuclear effects that will occur, discusses the implied design issues and suggests possible solutions so that a useful experimental facility can be built. 4 figs.

Hogan, W.J.

1987-11-02

83

Structure of beta-trimyristin and beta-tristearin from high-resolution X-ray powder diffraction data.  

PubMed

The crystal structures of beta-1,2,3-tritetradecanoylglycerol (beta-trimyristin or beta-MMM) and beta-1,2,3-trioctadecanoylglycerol (beta-tristearin or beta-SSS) have been determined from high-resolution synchrotron X-ray powder diffraction data. Grid search and Rietveld refinement have been used to determine and refine the structure, respectively. Both substances crystallize in space group P1; with Z = 2. The unit-cell parameters for beta-MMM are a = 12.0626 (6), b = 41.714 (1), c = 5.4588 (3) A, alpha = 73.388 (4), beta = 100.408 (5) and gamma = 118.274 (4) degrees. For beta-SSS the unit-cell parameters are a = 12.0053 (7), b = 51.902 (2), c = 5.4450 (3) A, alpha = 73.752 (5), beta = 100.256 (6) and gamma = 117.691 (5) degrees. Soft-distance restraints have been applied to the molecules during refinement. For beta-MMM the final R(p) value obtained is 0.053 and for beta-SSS the final R(p) value is 0.041. PMID:11373397

van Langevelde, A; Peschar, R; Schenk, H

2001-06-01

84

Impact of MHD Equilibrium Input Variations on the High-Beta Stability Boundaries of NSTX  

SciTech Connect

Ideal MHD stability limits of anticipated plasma configurations for the National Spherical Torus Experiment (NSTX) [Ono, M., et al., Nucl. Fusion 40 (2000) 557] and the dependence on the parameters defining the MHD equilibrium are evaluated. The study provides a quantitative computational evaluation of the stability limit variations induced by changes to the equilibrium of NSTX high-beta plasmas. The analysis is based on a reference free-boundary equilibrium with beta = 41.5%, monotonic safety factor q profile, and broad pressure profile p. On this reference target local variation of the plasma boundary, safety factor q, and pressure p profiles are imposed. Localized inflection of the outboard plasma boundary, produced by near-field effects from poloidal shaping field coils, weaken the stability due to the destabilization of high-n ballooning modes. Variation of the q profile at different radial location can also degrade stability. Both experimental profiles from existing tokamaks and spherical torus machines and profiles generated from transport modeling of anticipated neutral-beam-heated plasmas are used. Degraded stability is found at increasing pressure peaking factor due to the destabilization of n = 1 kink/ballooning modes. Direct access to the second region of stability is found in certain configurations and, for the entire set of variations considered, the lower calculated beta-limits values are still in the range of 20.0% without considering the stabilizing effect of the passive conducting structures.

F. Paoletti; S.A. Sabbagh; J. Manickam; J. Menard; R.J. Akers; D. Gates; S.M. Kaye; L. Lao

2001-03-20

85

Icrf Heating and Antenna Coupling in a High Beta Tokamak.  

NASA Astrophysics Data System (ADS)

Maxwell's Equations are solved in two-dimensions for the electromagnetic fields in a toroidal cavity using the cold plasma fluid dielectric tensor in the Ion Cyclotron Range of Frequencies (ICRF). The Vector Wave Equation is transformed to a set of two, coupled second-order partial differential equations with inhomogeneous forcing functions which model a wave launcher. The resulting equations are finite differenced and solved numerically with a complex banded matrix algorithm on a Cray-2 computer using a code described in this report. This code is used to study power coupling characteristics of a wave launcher for low and high beta tokamaks. The low and high beta equilibrium tokamak magnetic fields applied in this model are determined from analytic solutions to the Grad-Shafranov equation. The code shows good correspondence with the results of low field side ICRF heating experiments performed on the Tokamak of Fontenay-Aux-Roses (TFR). Low field side and high field side antenna coupling properties for ICRF heating in the Columbia High Beta Tokamak (HBT) experiment are calculated with this code. Variations of antenna position in the tokamak, ionic concentration and plasma density, and volume -averaged beta have been analyzed for HBT. It is found that the location of the antenna with respect to the plasma has the dominant role in the design of an ICRF heating experiment in HBT.

Elet, Richard Scott

1988-12-01

86

A high power, tuneable Free Electron Maser for Fusion  

NASA Astrophysics Data System (ADS)

In fusion devices the application of Electron Cyclotron Waves (ECW) has many attractive features. The absorption of ECW power yields localised heating and current drive, as well as control of plasma instabilities such as neo-classical tearing modes. For the next generation fusion devices a multi-frequency system (100 - 200 GHz) delivering tens of MW is required. For diagnostic and plasma-control purposes the frequency should be tuneable over several percent on a time-scale of tens of ms, e.g. for tracking plasma instabilities. In short, high unit-power, rapid tunability and a high system efficiency are needed. The Fusion-FEM (Free-Electron maser) at the FOM Institute "Rijnhuizen" in the Netherlands is the prototype of a high power, rapid-tuneable EC-wavesource. The design parameters are a net output power of 1 MW in the frequency range 130 - 260 GHz, tunable over several percent, and a system efficiency exceeding 50MeV dc electron beam, which is injected into a step-tapered undulator. A dc decelerator and a depressed collector recover the spent electron beam and increase the system efficiency to over 50 We report on generation of mm-wave output power of the Fusion-FEM. In short pulse operation (12 ms) a net output power around 200 GHz and 170 GHz is generated of 730 kW and 380 kW, respectively. The output mm-wave beam was analysed with a fast semi-conductor detector, a calorimeter, and an infrared camera with a heat-absorbing screen. The pictures from the IR camera show that the output beam is near-circular and has a Gaussian mode content exceeding 99.8 importance for almost all applications. The frequency analysis of the output beam shows that the device can operate in single-mode regime.

Urbanus, Wim

1999-11-01

87

A new high beta plasma device at UCLA  

NASA Astrophysics Data System (ADS)

We recently made a high beta plasma 30 eV and 100G < B< 250G) on the axis of a toroidal device at UCLA. The highest beta attained, ? 3, was at the lower field. The vacuum chamber is 30 meters in circumference, 2 meters wide and 3 meters tall. Using a weak vertical field, the 20 cm diameter plasma has made 4 rotations for a length of 120 m. Interestingly, at these plasma parameters the neutral penetration depth is shorter than the radius of the plasma, so we expect the plasma is fully ionized. The cathode used is amorphous Lanthanum Hexaboride (LaB6), which has more than 10 times the emission per area of the Barium Oxide cathode now used in the LAPD. Also LaB6 cathodes can be run in a hydrogen plasma and are relatively insensitive to oxygen leaks. We have developed a technique to make reliable large cathodes, the one in use is 400 cm^2. The magnetic field is steady state and the plasma is pulsed at 1 Hz with pulse lengths as long as 120 ms. The plasma is hundreds of parallel Alfv'en wavelengths long with a Lundquist number of 5000. Some experiments possible on this device are: fully three dimensional magnetic field line reconnection, Alfv'enic and MHD turbulence, studies of rotational transforms, physics of Alfv'en waves at high beta in Toroidal geometries, and high beta laser-plasma interactions.

Cooper, Chris; Gekelman, Walter; Pribyl, Patrick; Stattel, Stefanie; Derose, Kimberly; Carter, Troy

2008-11-01

88

An efficient expression of Human Growth Hormone (hGH) in the milk of transgenic mice using rat {beta}-casein/hGH fusion genes  

SciTech Connect

In order to produce human growth hormone (hGH) in the milk of transgenic mice, two expression vectors for hGH differing in their 3{prime} flanking sequences were constructed by placing the genomic sequences of hGH gene under the control of the rat {beta}-casein gene promotor. The 3{prime} flanking sequences of the expression constructs were derived from either the hGH gene (pBCN1GH) or the rat {beta}-casein gene (pBCN2GH). Transgenic lines bearing pBCN1GH expressed hGH more efficiently than those bearing pBCN2GH in the milk (19-5500 {mu}g/mL vs 0.7-2 {mu}g/mL). In particular, one of the BCN1GH lines expressed hGH as much as 5500 {plus_minus} 620 {mu}g/mL. Northern blot analysis showed that the transgene expression was specifically confined to the mammary gland and developmentally regulated like the endogeneous mouse {beta}-casein gene in the mammary gland. However, a low level of nonmammary expression was also detected with more sensitive assay methods. In conclusion, the rat {beta}-casein/hGH fusion gene could direct an efficient production of hGH in a highly tissue- and stage-specific manner in the transgenic mice and the 3{prime} flanking sequences of hGH gene had an important role for the efficient expression. 27 refs., 5 figs., 2 tabs.

Lee, Chul-Sang; Yu, Dae-Yeul; Lee, Kyung-Kwang [Korea Research Institute of Bioscience and Biotechnology, Taejon (Korea, Republic of)] [and others

1996-03-01

89

High-performance inertial confinement fusion target implosions on OMEGA  

SciTech Connect

The Omega Laser Facility is used to study inertial confinement fusion (ICF) concepts. This paper describes progress in direct-drive central hot-spot (CHS) ICF, shock ignition (SI) and fast ignition (FI) since the 2008 IAEA FEC conference. CHS cryogenic deuterium-tritium (DT) target implosions on OMEGA have produced the highest DT areal densities yet measured in ICF implosions (~300 mg cm{sup -2}). Integrated FI experiments have shown a significant increase in neutron yield caused by an appropriately timed high-intensity, high-energy laser pulse.

Meyerhofer, D. D.; McCrory, R L; Betti, R; Boehly, T R; Casey, D T; Collins, T.J.B.; Craxton, R S; Delettrez, J A; Edgell, D H; Epstein, R; Fletcher, K A; Frenje, J A; Glebov, Y Yu; Goncharov, V N; Harding, D R; Hu, S X; Igumenshchev, I V; Knauer, J P; Li, C K; Marozas, J A; Marshall, F J; McKenty, P W; Nilson, P M; Padalino, S P; Petrasso, R D; Radha, P B; Regan, S P; Sangster, T C; Seguin, F H; Seka, W; Short, R W; Shvarts, D; Skupsky, S; Soures, J M; Stoeckl, C; Theobald, W; Yaakobi, B

2011-04-18

90

High-performance inertial confinement fusion target implosions on OMEGA  

NASA Astrophysics Data System (ADS)

The Omega Laser Facility is used to study inertial confinement fusion (ICF) concepts. This paper describes progress in direct-drive central hot-spot (CHS) ICF, shock ignition (SI) and fast ignition (FI) since the 2008 IAEA FEC conference. CHS cryogenic deuterium-tritium (DT) target implosions on OMEGA have produced the highest DT areal densities yet measured in ICF implosions (~300 mg cm-2). Integrated FI experiments have shown a significant increase in neutron yield caused by an appropriately timed high-intensity, high-energy laser pulse.

Meyerhofer, D. D.; McCrory, R. L.; Betti, R.; Boehly, T. R.; Casey, D. T.; Collins, T. J. B.; Craxton, R. S.; Delettrez, J. A.; Edgell, D. H.; Epstein, R.; Fletcher, K. A.; Frenje, J. A.; Glebov, Y. Yu.; Goncharov, V. N.; Harding, D. R.; Hu, S. X.; Igumenshchev, I. V.; Knauer, J. P.; Li, C. K.; Marozas, J. A.; Marshall, F. J.; McKenty, P. W.; Nilson, P. M.; Padalino, S. P.; Petrasso, R. D.; Radha, P. B.; Regan, S. P.; Sangster, T. C.; Séguin, F. H.; Seka, W.; Short, R. W.; Shvarts, D.; Skupsky, S.; Soures, J. M.; Stoeckl, C.; Theobald, W.; Yaakobi, B.

2011-05-01

91

High beta plasma operation in a toroidal plasma producing device  

DOEpatents

A high beta plasma is produced in a plasma producing device of toroidal configuration by ohmic heating and auxiliary heating. The plasma pressure is continuously monitored and used in a control system to program the current in the poloidal field windings. Throughout the heating process, magnetic flux is conserved inside the plasma and the distortion of the flux surfaces drives a current in the plasma. As a consequence, the total current increases and the poloidal field windings are driven with an equal and opposing increasing current. The spatial distribution of the current in the poloidal field windings is determined by the plasma pressure. Plasma equilibrium is maintained thereby, and high temperature, high beta operation results.

Clarke, John F. (Oak Ridge, TN)

1978-01-01

92

Fusion with highly spin polarized HD and D sub 2  

SciTech Connect

During the course of this grant, we succeeded in overcoming essentially all of the obstacles on the route to carrying out ICF shots with polarized deuteron fuel in plastic target shells. ICF with polarized deuterons is expected to answer the question of survival of polarization in the high temperature plasma prior to fusion, as well as to give quantitative information on anisotropic particle emissions and possible suppression of particular fusion reactions. The techniques previously developed for high D polarization in large solid HD samples have been adapted to polystyrene target shells which are cooled conductively via very thin metal wire supports. An independent NMR experiment on a normal-D{sub 2}-filled glass target shell with 2 {mu}m copper-coated spider silk supports affirmed the thermal conduction adequacy by registering very low sample temperatures in the presence of the generation of considerable D{sub 2} conversion heat. In a permeation experiment employing very pure ortho-D{sub 2}, it was demonstrated that hydrogens diffuse into polystyrene shells at room temperature without molecular dissociation, a requirement for preservation of the composition of our HD samples used for polarization. An advanced version of the permeation apparatus was designed and constructed which permits preparation of target shells loaded with very high density HD or D{sub 2} fuels. That system includes provision for cryocondensation and cold-transfer either to the dilution refrigerator for polarization or to the OMEGA fusion chamber for ICF experiments with denser unpolarized fuel targets than were heretofore realizable in plastic target shells. a major effort resulted in improvements of cold-transfer inter-apparatus mating procedures which minimize the temperature rise of the target shells over that of the helium reservoir temperature. High D polarization in solid pure 0-D{sub 2} was shown to be retained into the liquid state after rapid melting.

Honig, A. (Syracuse Univ., NY (USA). Dept. of Physics); Kremens, R.; Skupsky, S. (Rochester Univ., NY (USA). Lab. for Laser Energetics)

1991-05-05

93

Resistive Wall Mode Physics and Control to Sustain High Normalized Beta in NSTX  

NASA Astrophysics Data System (ADS)

High bootstrap current fraction and efficient fusion production needed in continuously operating spherical torus fusion devices require plasmas with low plasma internal inductance, li, and high beta. Present research in NSTX focuses on greater understanding and verification of kinetic resistive wall mode (RWM) stabilization physics and analysis of improved active control techniques that have reduced disruptions in these plasmas. MISK code calculations indicate that the largest stabilizing kinetic effect comes from resonance between the mode and the precession motion of trapped thermal ions. The stabilizing effect of energetic particles depends on their anisotropic distribution, which also modifies the pressure-driven destabilization term. Long-pulse plasmas have reached ?N/li> 13. A positive and counter-intuitive result is that the greatest disruption probability does not occur at the highest ?N, or ?N/li, but at lower values closer to the n = 1 no-wall stability limit. The result can be understood by evaluating kinetic RWM stability for time-varying plasma rotation and equilibrium profiles, and is further examined by resonant field amplification evolution in kinetically stabilized plasmas at high ?N.

Berkery, J. W.; Sabbagh, S. A.; Bialek, J. M.; Park, Y. S.; Gerhardt, S. P.; Bell, R. E.; Leblanc, B. P.

2012-10-01

94

Developing high brightness beams for heavy ion driven inertial fusion  

SciTech Connect

Heavy ion fusion (HIF) drivers require large currents and bright beams. In this paper we review the two different approaches for building HIF injectors and the corresponding ion source requirements. The traditional approach uses large aperture, low current density ion sources, resulting in a very large injector system. A more recent conceptual approach merges high current density mini-beamlets into a large current beam in order to significantly reduce the size of the injector. Experiments are being prepared to demonstrate the feasibility of this new approach.

Kwan, J.W.; Ahle, L.A.; Anders, A.; Bieniosek, F.M.; Chacon-Golcher, E.; Grote, D.P.; Henestroza, E.; Leung, K.N.; Molvik, A.W.

2001-08-29

95

Resistive ballooning modes in high-beta tokamaks  

Microsoft Academic Search

Resistive ballooning mode stability is examined using one-fluid, two-fluid, and kinetic theories to determine the domain of validity of the resistive-fluid theories in the high-beta Doublet III tokamak. In general, it is found that the requirements for the validity of the resistive-fluid theories in Doublet III are only satisfied on the cold, outermost edge of the plasma with temperatures T

R. W. Moore; R. R. Dominguez; M. S. Chu

1985-01-01

96

Beta-thalassemia intermedia with exceptionally high hemoglobin A2: relationship to mutations in the beta-gene promoter.  

PubMed

Small deletions of the 5' portion of the beta-globin gene that remove the promoters but stop 3' to the delta-globin gene are recognized as the sole cause of beta-thalassemia with exceptionally high hemoglobin A2 (HbA2) levels. Two patients with beta-thalassemia intermedia and exceptionally high levels of HbA2 (10.4 and 12.0%) were examined. One patient was a combined heterozygote for the -88 C----T and a novel -87 C----A mutation, while the other was homozygous for the -29 A----G beta(+)-thalassemia mutation. The remainder of the beta genes were normal. There was no evidence for deletions involving the 5' portion of the beta gene or the region between the beta and delta genes. Gene mapping studies excluded the possibility of a beta delta-anti-Lepore hemoglobin gene with beta promoters and delta coding sequences. There were no mutations in the promoters of the G gamma or A gamma-globin genes that have been associated with the hereditary persistence of HbF phenotype. The delta-globin gene promoters were normal from codon 17 to position -145 relative to the mRNA capping site. There appears to be considerable heterogeneity of HbA2 and HbF levels in patients who are homozygous or mixed heterozygotes for mutations in the TATA box and other promoter elements of the beta-globin gene. The capacity for proteolysis within the erythrocyte may vary among individuals. The authors hypothesize that in the exceptionally high HbA2 beta-thalassemia intermedia phenotype, proteolysis of superfluous alpha-globin chains is less efficient than in patients with customary levels of HbA2.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1380206

Coleman, M B; Adams, J G; Plonczynski, M W; Harrell, A H; Walker, A M; Fairbanks, V; Steinberg, M H

1992-08-01

97

High-{beta} equilibria in tokamaks with toroidal flow  

SciTech Connect

We extend existing 2-D analytical high-{beta} equilibrium solutions obtained by Cowley et al.[Phys. Fluids B 3, 2066 (1991)] and Hsu et al.[Phys. Plasmas 3, 266 (1996)] to the case of toroidally flowing plasma, assuming ideal magnetohydrodynamics and isothermal magnetic surfaces. Invoking the ordering {beta}q{sup 2}>>{epsilon}{sup 2} and M{sub {phi}}{sup 2}q{sup 2}>>{epsilon}, we solve the boundary layer problem, re-obtaining the static solution in the zero flow limit. The phenomenon of extreme plasma diamagnetism in the static solution was found to be reduced due to centrifugal drift currents for significant toroidal flow. Example equilibrium calculations are presented using plasma parameters which are approaching attainable values in next generation spherical tokamaks.

Fitzgerald, Michael; Hole, Matthew [Research School of Physical Sciences and Engineering, Australian National University, 0200 ACT (Australia); Sharapov, Sergei [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB (United Kingdom)

2011-09-15

98

SMALL SCALE FUSION THE PULSED HIGH DENSITY FRC EXPERIMENT  

Microsoft Academic Search

It is quite possible that nuclear fusion will be the only source that can provide the prodigious power demands that the world will face in the future. The difficulty however for most nuclear fusion concepts is the complexity and large mass associated with the confinement systems. Essentially, the more massive the system required to confine and heat the fusion plasma,

John Slough

99

Fusion reactors as high-temperature process heat sources  

Microsoft Academic Search

The reasons for interest in fusion process heat sources, the present United States requirements for process heat, and process industry criteria for selection of thermal energy sources are reviewed. Constraints on process heat fusion reactor design, conceptual solutions to design problems, and energy delivery characteristics of present process heat fusion reactor concepts are described. Projections of the time frame and

J. H. Pendergrass; L. A. Booth

1981-01-01

100

Anterior cervical fusion with interbody cage containing beta-tricalcium phosphate augmented with plate fixation: a prospective randomized study with 2-year follow-up.  

PubMed

A variety of bone graft substitutes, interbody cages, and anterior plates have been used in cervical interbody fusion, but no controlled study was conducted on the clinical performance of beta-tricalcium phosphate (beta-TCP) and the effect of supplemented anterior plate fixation. The objective of this prospective, randomized clinical study was to evaluate the effectiveness of implanting interbody fusion cage containing beta-TCP for the treatment of cervical radiculopathy and/or myelopathy, and the fusion rates and outcomes in patients with or without randomly assigned plate fixation. Sixty-two patients with cervical radiculopathy and/or myelopathy due to soft disc herniation or spondylosis were treated with one- or two-level discectomy and fusion with interbody cages containing beta-TCP. They were randomly assigned to receive supplemented anterior plate (n = 33) or not (n = 29). The patients were followed up for 2 years postoperatively. The radiological and clinical outcomes were assessed during a 2-year follow-up. The results showed that the fusion rate (75.0%) 3 months after surgery in patients treated without anterior cervical plating was significantly lower than that (97.9%) with plate fixation (P < 0.05), but successful bone fusion was achieved in all patients of both groups at 6-month follow-up assessment. Patients treated without anterior plate fixation had 11 of 52 (19.2%) cage subsidence at last follow-up. No difference (P > 0.05) was found regarding improvement in spinal curvature as well as neck and arm pain, and recovery rate of JOA score at all time intervals between the two groups. Based on the findings of this study, interbody fusion cage containing beta-TCP following one- or two-level discectomy proved to be an effective treatment for cervical spondylotic radiculopathy and/or myelopathy. Supplemented anterior plate fixation can promote interbody fusion and prevent cage subsidence but do not improve the 2-year outcome when compared with those treated without anterior plate fixation. PMID:18301927

Dai, Li-Yang; Jiang, Lei-Sheng

2008-02-27

101

Fully electromagnetic gyrokinetic eigenmode analysis of high-beta shaped plasmas  

NASA Astrophysics Data System (ADS)

A new, more efficient method to compute unstable linear gyrokinetic eigenvalues and eigenvectors has been developed for drift-wave analysis of plasmas with arbitrary flux-surface shape, including both transverse and compressional magnetic perturbations. In high-beta, strongly shaped plasmas like in the National Spherical Torus Experiment (NSTX) [M. Ono et al., Nucl. Fusion 40, 557 (2000)], numerous branches of closely spaced unstable eigenmodes exist. These modes are difficult and time-consuming to adequately resolve with the existing linear initial-value solvers, which are further limited to the most unstable eigenmode. The new method is based on an eigenvalue approach and is an extension of the GYRO code [J. Candy and R. E. Waltz, J. Comput. Phys. 186, 545 (2003)], reusing the existing discretization schemes in both real and velocity-space. Unlike recent methods, which use an iterative solver to compute eigenvalues of the relatively large gyrokinetic response matrix, the present scheme computes the zeros of the much smaller Maxwell dispersion matrix using a direct method. In the present work, the new eigensolver is applied to gyrokinetic stability analysis of a high-beta, NSTX-like plasma. We illustrate the smooth transformation from ion-temperature-gradient (ITG)-like to kinetic-ballooning (KBM)-like modes, and the formation of hybrid ITG/KBM modes, and further demonstrate the existence of high-k Alfvénic drift-wave ``cascades'' for which the most unstable mode is a higher excited state along the field line. A new compressional electron drift wave, which is driven by a combination of strong beta and pressure gradient, is also identified for the first time. Overall, we find that accurate calculation of stability boundaries and growth rates cannot, in general, ignore the compressional component ?B? of the perturbation.

Belli, E. A.; Candy, J.

2010-11-01

102

High resolution imaging systems for inertial confinement fusion experiments  

NASA Astrophysics Data System (ADS)

The path to successful inertial confinement fusion (ICF) requires to observe and control the micro balloon deformations. This will be achieved using X-ray microscope among other diagnostics. A high resolution, high energy X-ray microscope involving state-of-the-art toroidal mirrors and multilayer coatings is described. Years of experiments and experience have led to a small-scale X-ray plasma imager that proves the feasibility of all the features required for a LMJ diagnostic: spatial resolution of 5?m, broad bandwidth, millimetric field of view (FOV). Using the feedback given by this diagnostic, a prototype for the Laser MegaJoule (LMJ) experiments has been designed. The experimental results of the first diagnostic and the concepts of the second are discussed.

Dennetiere, D.; Audebert, P.; Bahr, R.; Bole, S.; Bourgade, J. L.; Brannon, B.; Girard, F.; Pien, G.; Troussel, Ph.

2012-10-01

103

Physics issues in the design of high-beta, low-aspect-ratio stellarator experiments  

NASA Astrophysics Data System (ADS)

High-beta, low-aspect-ratio (``compact'') stellarators are promising solutions to the problem of developing a magnetic plasma configuration for magnetic fusion power plants that can be sustained in steady state without disrupting. These concepts combine features of stellarators and advanced tokamaks and have aspect ratios similar to those of tokamaks (2-4). They are based on computed plasma configurations that are shaped in three dimensions to provide desired stability and transport properties. Experiments are planned as part of a program to develop this concept. A ?=4% quasi-axisymmetric plasma configuration has been evaluated for the National Compact Stellarator Experiment (NCSX). It has a substantial bootstrap current and is shaped to stabilize ballooning, external kink, vertical, and neoclassical tearing modes without feedback or close-fitting conductors. Quasi-omnigeneous plasma configurations stable to ballooning modes at ?=4% have been evaluated for the Quasi-Omnigeneous Stellarator (QOS) experiment. These equilibria have relatively low bootstrap currents and are insensitive to changes in beta. Coil configurations have been calculated that reconstruct these plasma configurations, preserving their important physics properties. Theory- and experiment-based confinement analyses are used to evaluate the technical capabilities needed to reach target plasma conditions. The physics basis for these complementary experiments is described.

Neilson, G. H.; Reiman, A. H.; Zarnstorff, M. C.; Brooks, A.; Fu, G.-Y.; Goldston, R. J.; Ku, L.-P.; Lin, Z.; Majeski, R.; Monticello, D. A.; Mynick, H.; Pomphrey, N.; Redi, M. H.; Reiersen, W. T.; Schmidt, J. A.; Hirshman, S. P.; Lyon, J. F.; Berry, L. A.; Nelson, B. E.; Sanchez, R.; Spong, D. A.; Boozer, A. H.; Miner, W. H.; Valanju, P. M.; Cooper, W. A.; Drevlak, M.; Merkel, P.; Nuehrenberg, C.

2000-05-01

104

Highly radiation-resistant vacuum impregnation resin systems for fusion magnet insulation  

Microsoft Academic Search

Magnets built for fusion devices such as the newly proposed Fusion Ignition Research Experiment (FIRE) need to be highly reliable, especially in a high radiation environment. Insulation materials are often the weak link in the design of superconducting magnets due to their sensitivity to high radiation doses, embrittlement at cryogenic temperatures, and the limitations on their fabricability. An insulation system

P. E. Fabian; N. A. Munshi; R. J. Denis

2002-01-01

105

High convergence, indirect drive inertial confinement fusion experiments at Nova  

SciTech Connect

High convergence, indirect drive implosion experiments have been done at the Nova Laser Facility. The targets were deuterium and deuterium/tritium filled, glass microballoons driven symmetrically by x rays produced in a surrounding uranium hohlraum. Implosions achieved convergence ratios of 24:1 with fuel densities of 19 g/cm{sup 3}; this is equivalent to the range required for the hot spot of ignition scale capsules. The implosions used a shaped drive and were well characterized by a variety of laser and target measurements. The primary measurement was the fuel density using the secondary neutron technique (neutrons from the reaction {sup 2}H({sup 3}H,n){sup 4}He in initially pure deuterium fuel). Laser measurements include power, energy and pointing. Simultaneous measurement of neutron yield, fusion reaction rate, and x-ray images provide additional information about the implosion process. Computer models are in good agreement with measured results.

Lerche, R.A.; Cable, M.D.; Hatchett, S.P. [and others

1995-06-02

106

Remarks on detecting high-energy deuterium tritium fusion gamma rays using a gas Cherenkov detector  

Microsoft Academic Search

As fusion ignition conditions are approached using the national ignition facility (NIF), independent high-bandwidth gamma-ray fusion burn measurements become essential complements to information obtained from neutron diagnostics. The 16.75-MeV gamma rays that accompany deuterium tritium (d+t) fusion can be detected using a high-bandwidth gaseous carbon dioxide Cherenkov threshold detector. The detection energy threshold was set by the CO2 gas pressure.

J. M. Mack; R. R. Berggren; S. E. Caldwell; C. R. Christensen; S. C. Evans; J. R. Faulkner Jr.; R. L. Griffith; G. M. Hale; R. S. King; D. K. Lash; R. A. Lerche; J. A. Oertel; D. M. Pacheco; C. S. Young

2006-01-01

107

Evaluation of hydroxyapatite and beta-tricalcium phosphate mixed with bone marrow aspirate as a bone graft substitute for posterolateral spinal fusion  

PubMed Central

Background: Autologous cancellous bone is the most effective biological graft material. However, harvest of autologous bone is associated with significant morbidity. Since porous hydroxyapatite and beta-tricalcium phosphate are biodegradable materials and can be replaced by bone tissue, but it lacks osteogenic property. We conducted a study to assess their use as a scaffold and combine them with bone marrow aspirate for bone regeneration using its osteogenic property for posterolateral spinal fusion on one side and autologous bone graft on the other side and compare them radiologically in terms of graft incorporation and fusion. Materials and Methods: Thirty patients with unstable dorsal and lumbar spinal injuries who needed posterior stabilization and fusion were evaluated in this prospective study from October 2005 to March 2008. The posterior stabilization was done using pedicle screw and rod assembly, and fusion was done using hydroxyapatite and beta-tricalcium phosphate mixed with bone marrow aspirate as a bone graft substitute over one side of spine and autologous bone graft obtained from iliac crest over other side of spine. The patients were followed up to a minimum of 12 months. Serial radiographs were done at an interval of 3, 6, and 12 months and CT scan was done at one year follow-up. Graft incorporation and fusion were assessed at each follow-up. The study was subjected to statistical analysis using chi-square and kappa test to assess graft incorporation and fusion. Results: At the end of the study, radiological graft incorporation and fusion was evident in all the patients on the bone graft substitute side and in 29 patients on the autologous bone graft side of the spine (P > 0.05). One patient showed lucency and breakage of distal pedicle screw in autologous bone graft side. The interobserver agreement (kappa) had an average of 0.72 for graft incorporation, 0.75 for fusion on radiographs, and 0.88 for the CT scan findings. Conclusion: Hydroxyapatite and beta-tricalcium phosphate mixed with bone marrow aspirate seems to be a promising alternative to conventional autologous iliac bone graft for posterolateral spinal fusion.

Bansal, Sanjay; Chauhan, Vijendra; Sharma, Sansar; Maheshwari, Rajesh; Juyal, Anil; Raghuvanshi, Shailendra

2009-01-01

108

Sequence of a highly divergent beta tubulin gene reveals regional heterogeneity in the beta tubulin polypeptide  

PubMed Central

The nucleotide sequence of a chicken genomic DNA segment containing the chicken beta 4 tubulin gene has been determined. The predicted amino acid sequence of beta 4 is surprisingly divergent from that of the chicken beta 2 gene that encodes the dominant neural beta tubulin. beta 4 differs from beta 2 at 36 residue positions and encodes a polypeptide that is four amino acids longer, yielding a divergence of 8.9% between the two beta tubulin isotypes. While many of the amino acid substitutions are conservative, several involve significant alteration in the physiochemical properties of the residue. Furthermore, the amino acid substitution positions are not randomly located within the primary sequence but are distinctly clustered: major divergence occurs in the carboxy-terminal region beyond residue 430 and within the second protein coding exon segments of the genes. In addition, large regions of absolute sequence conservation are also present. Certain sequences within the heterogeneous regions are conserved in other species, indicating that these regions are under positive evolutionary selection pressure and are therefore probably essential for some aspect of beta- tubulin function. These findings strongly suggest that regional amino acid sequence heterogeneity may play an important role in the establishment of functionally differentiated beta tubulin polypeptides.

1984-01-01

109

High-beta plasma blobs in the morningside plasma sheet  

NASA Astrophysics Data System (ADS)

Equator-S frequently encountered, i.e. on 30% of the orbits between 1 March and 17 April 1998, strong variations of the magnetic field strength of typically 5-15-min duration outside about 9RE during the late-night/early-morning hours. Very high-plasma beta values were found, varying between 1 and 10 or more. Close conjunctions between Equator-S and Geotail revealed the spatial structure of these plasma blobs and their lifetime. They are typically 5-10° wide in longitude and have an antisymmetric plasma or magnetic pressure distribution with respect to the equator, while being altogether low-latitude phenomena (< 15°). They drift slowly sunward, exchange plasma across the equator and have a lifetime of at least 15-30 min. While their spatial structure may be due to some sort of mirror instability, little is known about the origin of the high-beta plasma. It is speculated that the morningside boundary layer somewhat further tailward may be the source of this plasma. This would be consistent with the preference of the plasma blobs to occur during quiet conditions, although they are also found during substorm periods. The relation to auroral phenomena in the morningside oval is uncertain. The energy deposition may be mostly too weak to generate a visible signature. However, patchy aurora remains a candidate for more disturbed periods.

Haerendel, G.; Baumjohann, W.; Georgescu, E.; Nakamura, R.; Kistler, L. M.; Klecker, B.; Kucharek, H.; Vaivads, A.; Mukai, T.; Kokubun, S.

1999-12-01

110

High-power pulsed lasers used in fusion research  

SciTech Connect

This paper gives an overview of the Nd:glass laser target irradiation facilities constructed and operated for fusion research at the Lawrence Livermore National Laboratory. These type of facilities, both at LLNL and elsewhere in the world, have resulted in an extremely useful tool for studying many of the plasma physics processes involved in inertial confinement fusion.

Hunt, J.T.

1982-01-01

111

Observation of high-energy deuterium–tritium fusion gamma rays using gas Cherenkov detectors  

Microsoft Academic Search

As fusion ignition conditions are approached using the National Ignition Facility (NIF), independent high-bandwidth gamma-ray fusion-burn measurements become essential complements to neutron-based methods. Time resolution ?20ps (10–30GHz), energy discrimination, and significant stand off distance may be needed for credible burn history measurements.The 16.75MeV gamma rays that accompany deuterium–tritium (d+t) fusion provide a high-bandwidth alternative to 14MeV fusion neutrons for d+t

J. M. Mack; R. R. Berggren; S. E. Caldwell; S. C. Evans; J. R. Faulkner; R. A. Lerche; J. A. Oertel; C. S. Young

2003-01-01

112

Observation of high-energy deuterium-tritium fusion gamma rays using gas Cherenkov detectors  

Microsoft Academic Search

As fusion ignition conditions are approached using the National Ignition Facility (NIF), independent high-bandwidth gamma-ray fusion-burn measurements become essential complements to neutron-based methods. Time resolution ~20ps (10-30GHz), energy discrimination, and significant stand off distance may be needed for credible burn history measurements. The 16.75MeV gamma rays that accompany deuterium-tritium (d+t) fusion provide a high-bandwidth alternative to 14MeV fusion neutrons for

J. M. Mack; R. R. Berggren; S. E. Caldwell; S. C. Evans; J. R. Faulkner; R. A. Lerche; J. A. Oertel; C. S. Young

2003-01-01

113

High-Gain Direct-Drive Target Design for Laser Fusion (Preprint).  

National Technical Information Service (NTIS)

A new laser fusion target concept is presented with a predicted energy gain of 125 using a 1.3 MJ KrF laser. This energy gain is sufficiently high for an economically attractive fusion reactor. X-rays from high- and low-Z materials are used in combination...

A. J. Schmitt D. G. Colombant M. Klapisch S. E. Bodner

2000-01-01

114

High Precision Measurements of Neutron Beta-Decay at LANSCE  

NASA Astrophysics Data System (ADS)

High precision measurements of neutron beta-decay can be used to study the standard model of particle physics by testing the unitarity condition of the CKM matrix. Precise measurements of the neutrons' lifetime and one of its angular correlations are needed to determine the necessary standard model parameters for a unitarity test from neutron decay alone. Several experiments are underway at the Los Alamos Neutron Science Center (LANSCE) to measure these parameters using Ultra-Cold Neutrons (UCN). During the last 10 year a program to study neutron physics with UCN has been under development at LANSCE by an international team of scientists. The first experiment of this program, UCNA; which measures the decay correlation between the polarized neutron and the resulting beta particle, is currently running. A neutron lifetime experiment that monitors the decay rate of UCN trapped in a magnetic bottle with a gravitational top is being built and scheduled to run later this year. A second decay correlation experiment; (UCNB), which will measure the decay correlation between the polarized neutron and the resulting anti-neutrino is currently in the research and development phase. This talk will give an overview of these experiments, as well as other highlights from the UCN program at LANSCE.

Makela, Mark

2009-10-01

115

The high current transport experiment for heavy ion inertial fusion  

SciTech Connect

The High Current Experiment (HCX) at Lawrence Berkeley National Laboratory is part of the US program to explore heavy-ion beam transport at a scale representative of the low-energy end of an induction linac driver for fusion energy production. The primary mission of this experiment is to investigate aperture fill factors acceptable for the transport of space-charge-dominated heavy-ion beams at high space-charge intensity (line charge density {approx} 0.2 {micro}C/m) over long pulse durations (>4 ms) in alternating gradient electrostatic and magnetic quadrupoles. This experiment is testing--at driver-relevant scale--transport issues resulting from nonlinear space-charge effects and collective modes, beam centroid alignment and beam steering, matching, image charges, halo, electron cloud effects, and longitudinal bunch control. We present the results for a coasting 1 MeV K{sup +} ion beam transported through the first ten electrostatic transport quadrupoles, measured with beam-imaging and phase-space diagnostics. The latest additions to the experiment include measurements of the secondary ion, electron and atom coefficients due to halo ions scraping the wall, and four magnetic quadrupoles to explore similar issues in magnetic channels.

Seidl, P.A.; Baca, D.; Bieniosek, F.M.; Celata, C.M.; Faltens, A.; Prost, L.R.; Sabbi, G.; Waldron, W.L.; Cohen, R.; Friedman, A.; Lund, S.M.; Molvik, A.W.; Haber, I.

2003-05-01

116

Development in DIII-D of High Beta Discharges Appropriate for Steady-state Tokamak Operation With Burning Plasmas  

SciTech Connect

Ideally, tokamak power plants will operate in steady-state at high fusion gain. Recent work at DIII-D on the development of suitable high beta discharges with 100% of the plasma current generated noninductively (f{sub NI} = 1) is described. In a discharge with 1.5 < q{sub min} <2, a scan of the discharge shape squareness was used to find the value that maximizes confinement and achievable {beta}{sub N}. A small bias of the up/down balance of the double-null divertor shape away from the ion B x {del}B drift direction optimizes pumping for minimum density. Electron cyclotron current drive with a broad deposition profile was found to be effective at avoidance of a 2/1 NTM allowing long duration at {beta}{sub N} = 3.7. With these improvements, surface voltage {approx} 0-10 mV, indicating f{sub NI} {approx} 1, was obtained for 0.7 {tau}{sub R} (resistive time). Stationary discharges with {beta}{sub N} = 3.4 and f{sub NI} {approx} 0.9 that project to Q = 5 in ITER have been demonstrated for {tau}{sub R}. For use in development of model based controllers for the q profile, transport code models of the current profile evolution during discharge formation have been validated against the experiment. Tests of available actuators confirm that electron heating during the plasma current ramp up to modify the conductivity is by far the most effective. The empirically designed controller has been improved by use of proportional/integral gain and built-in limits to {beta}{sub N} to avoid instabilities. Two alternate steady-state compatible scenarios predicted to be capable of reaching {beta}{sub N} = 5 have been tested experimentally, motivated by future machines that require high power density and neutron fluence. In a wall stabilized scenario with q{sub min} > 2, {beta}{sub N} = 4 has been achieved for 2 s {approx} {tau}{sub R}. In a high internal inductance scenario, which maximizes the ideal no-wall stability limit, {beta}{sub N} {approx} 4.8 has been reached with f{sub NI} > 1.

Ferron, J R; Basiuk, V; Casper, T A; Challis, C D; DeBoo, J C; Doyle, E J; Gao, Q; Garofalo, A M; Greenfield, C M; Holcomb, C T; Hyatt, A W; Ide, S; Luce, T C; Murakami, M; Ou, Y; Park, J; Petrie, T W; Petty, C C; Politzer, P A; Reimerdes, H; Schuster, E; Schneider, M; Wang, A

2008-10-13

117

High Power Density Blanket Design Study for Fusion Reactors  

NASA Astrophysics Data System (ADS)

A conceptual design study of a high power density blanket has been carried out. The Fusion Experimental Breeder, FEB, is adopted as the reference reactor. The neutron wall loading is 0.5 MW/m2. The blanket is cooled by 10 MPa helium in tube. The concept of LiPb eutectic/transuranium oxide suspension is adopted. The neutronics design is performed to provide the design basis, and it gives an energy multiplication of 37 and a flattened power density distribution with a peak value of 70 W/m3. Multiple cooling panels are introduced to reduce the peak temperature of the blanket. In spite of up to 15 cooling panels, the blanket module is calculated using the ANSYS code and analytically as well. The results are consistent with each other and can meet the thermal criteria. However, structural calculation results from ANSYS did not satisfy the criterion: The blanket structure design is then improved by using curved cooling panels to model the structure in detail. Temperature distribution is obtained using the Pro/Mechanica code. Detailed structural analyses are also done by this code. Some satisfactory results are obtained.

Huang, J. H.; Zhu, Y. K.; Deng, P. Zh.

2003-06-01

118

Applications of high-power millimeter waves in fusion energy research  

Microsoft Academic Search

High-power millimeter wave sources are a key enabling technology in fusion energy research. The present state of the art of application of these sources to the areas of heating, current generation, and scattering for diagnostic purposes in fusion plasmas is reviewed. The extrapolation of these applications to future devices and the requirements which they place on sources and transmission lines

Timothy C. Luce

2002-01-01

119

Web Presentation to Raise Awareness of High School Students about Fusion Science  

Microsoft Academic Search

A growing awareness and understanding within mainstream America of the role of fusion science in our future is critical to the optimal growth of fusion energy science programs. High school students interested in science and global energy concerns are in an excellent position to use the vast potential of the World Wide Web (WWW) to share information and opinions about

Jessica Hicks; Mark Calvin

1996-01-01

120

Total beta-globin gene deletion has high frequency in Filipinos  

SciTech Connect

The distribution of {beta}-thalassemia [{beta}{sup Th}] mutations is unique to each ethnic group. Most mutations affect one or a few bases; large deletions have been rare. Among families screened in Hawaii, [{beta}{sup Th}] heterozygotes were diagnosed by microcytosis, absence of abnormal hemoglobins on isoelectric focusing, and raised Hb A{sub 2} by chromatography. Gene frequency for {beta}{sup Th} was 0.02 in Filipinos. In Filipinos, polymerase chain reaction [PCR] with denaturing gradient gel electrophoresis for {beta}{sup Th} mutations detected a mutation in only 6 of 42 {beta}{sup Th} heterozygotes; an IVS2-666 C/T polymorphism showed non-heterozygosity in 37 and heterozygosity in only 5 of these {beta}{sup Th} heterozygotes. One {beta}{sup Th}/{beta}{sup Th} major patient and his mother had no mutation detected by allele-specific oligomer hybridization; PCR failed to amplify any DNA from his {beta}-globin gene. After a total {beta}-globin gene deletion [{beta}{sup Del}] was found in a Filipino family in Ontario, specific PCR amplification for {beta}{sup Del} detected this in 43 of 53 {beta}{sup Th} Filipino samples tested; the above {beta}{sup Th}/{beta}{sup Th} patient was a ({beta}{sup Del}/{beta}{sup Del}) homozygote. The {beta}{sup Del} may account for over 60% of all {beta}{sup Th} alleles in Filipinos; this is the highest proportion of a deletion {beta}{sup Th} mutation reported from any population. Most but not all {beta}{sup Del} heterozygotes had high Hb F [5.13 {plus_minus} 3.94 mean {plus_minus} 1 s.d.] compared to the codon 41/42 four base deletion common in Chinese [2.30 {plus_minus} 0.86], or to {beta}{sup Th} heterozygotes with normal {alpha}-globin genes [2.23 {plus_minus} 0.80].

Patrick, N.; Miyakawa, F.; Hunt, J.A. [Univ. of Hawaii, Honolulu, HI (United States)] [and others

1994-09-01

121

New directions in fusion machines: report on the MFAC Panel X on high power density options  

SciTech Connect

The high cost of fusion is motivating a shift in research interest toward smaller, lower-cost systems. Panel X of the Magnetic Fusion Advisory Committee (MFAC) was charged to assess the potential benefits and problems associated with small, high-power-density approaches to fusion. The Panel identified figures of merit which are useful in evaluating various approaches to reduce the development costs and capital costs of fusion systems. As a result of their deliberations, the Panel recommended that ''...increased emphasis should be given to improving the mass power density of fusion systems, aiming at a minimum target of 100 kWe/tonne'', and that ''Increased emphasis should be given to concepts that offer the potential to reduce substantially the cost of development steps in physics and technology.''

Linford, R.K.

1985-01-01

122

High-gain direct-drive target design for laser fusion  

SciTech Connect

A new laser fusion target concept is presented with a predicted energy gain of 127 using a 1.3 MJ KrF laser. This energy gain is sufficiently high for an economically attractive fusion reactor. X rays from high- and low-Z materials are used in combination with a low-opacity ablator to spatially tune the isentrope, thereby providing both high fuel compression and a reduction of the ablative Rayleigh-Taylor instability. (c) 2000 American Institute of Physics.

Bodner, S. E. [Plasma Physics Division, Naval Research Laboratory, Washington, D.C. 20375 (United States); Colombant, D. G. [Plasma Physics Division, Naval Research Laboratory, Washington, D.C. 20375 (United States); Schmitt, A. J. [Plasma Physics Division, Naval Research Laboratory, Washington, D.C. 20375 (United States); Klapisch, M. [Plasma Physics Division, Naval Research Laboratory, Washington, D.C. 20375 (United States)

2000-06-01

123

Analytic, High-beta Solutions of the Helical Grad-Shafranov Equation  

SciTech Connect

We present analytic, high-beta ({beta} {approx} O(1)), helical equilibrium solutions for a class of helical axis configurations having large helical aspect ratio, with the helix assumed to be tightly wound. The solutions develop a narrow boundary layer of strongly compressed flux, similar to that previously found in high beta tokamak equilibrium solutions. The boundary layer is associated with a strong localized current which prevents the equilibrium from having zero net current.

D.R. Smith; A.H. Reiman

2004-05-19

124

Applications of high power millimeter waves in the DIII-D fusion program  

SciTech Connect

First operation of a new generation of MW level, 110 GHz generator (gyrotron) on the DIII-D fusion experimental device has been achieved. The desire for high power, cw millimeter (mm) wave sources to support fusion research and development is just now beginning to be realized. Plasma heating and current drive with directed mm waves rely on the strong absorption achieved when the wave frequency matches the natural ``cyclotron`` frequency of electrons in a magnetic field, or its harmonics. Recent progress in fusion experiments highlights the need for control of the interior details of the hot plasma, and nun wave systems are ideally suited for this role. A brief status of fusion research is given, and the importance of mm waves in the future directions for fusion research is described. The vacuum transmission components necessary for transmitting, monitoring, and launching high power 1 10 GHz waves into a plasma have been developed at General Atomics (GA) and will be described. High power mm waves have a number of attractive technological features for fusion applications compared with other candidate plasma heating and current drive technologies. Millimeter waves can be transmitted with high power density over large distances with low losses by utilizing corrugated waveguides, so the generators can be sited remotely, facilitating maintenance and saving valuable space near the fusion device.

Freeman, R.L.

1996-08-01

125

High-Power Pulsed Lasers Used in Fusion Research.  

National Technical Information Service (NTIS)

This paper gives an overview of the Nd:glass laser target irradiation facilities constructed and operated for fusion research at the Lawrence Livermore National Laboratory. These type of facilities, both at LLNL and elsewhere in the world, have resulted i...

J. T. Hunt

1982-01-01

126

High current vacuum arc ion source for heavy ion fusion  

Microsoft Academic Search

Summary form only given. Heavy Ion Fusion (HIF) is one of the approaches for the controlled thermonuclear power production. A source of heavy ions with charge states 1+ to 2+, in ≈0.5 A current beams with 20 ?s pulse widths and ~10 Hz repetition rates are required. Thermionic sources have been the workhorse for the HIF program to date, but

N. Qi; J. Schein; S. Gensler; R. R. Prasad; M. Krishnan; I. Brown

1999-01-01

127

Bounce-Averaged Stability Analysis of High Beta Flux Tubes  

NASA Astrophysics Data System (ADS)

A novel numerical procedure has been developed for analyzing the stability of a particular flux tube to ballooning-interchange modes in plasmas for which the beta value ? is very high O(1 ~ 10). The stability of a stressed dipole configuration in response to arbitrary fully electromagnetic perturbations is studied, including the effects of finite larmor radius, parallel electric fields, arbitrary complex frequency, and trapped/untrapped particle populations. This procedure has been applied to the problem of determining the trigger mechanism for magnetospheric substorms in the stressed geomagnetic tail where realistic equilibrium fields are used to compute the bounce averaged curvature and grad-B drifts. Previously, MHD-like modes were found to be unstable between two critical ? 's, (? 1, ?2). Local analysis concluded that instabilities due to kinetic resonances might persist above ? 2. In this work the local approximation is dropped yielding a large matrix eigenvalue problem for which a parallel machine is well suited. Results are compared to different fluid models that include Hall and finite larmor radius effects. The energy released by such unstable modes is calculated and compared with measurements of auroral brightening. This work was supported by the National Science Foundation Grant ATM-9907637 and the U.S. Dept. of Energy Contract No. DE-FG03-96ER-54346.

Crabtree, C.; Horton, W.; Wong, H.; Van Dam, J.

2001-12-01

128

Proposed Approach to Stable High Beta Plasmas in ET  

NASA Astrophysics Data System (ADS)

Five second long plasmas have been produced in ET with ease. We need these long pulses to evolve high beta equilibria under controlled conditions. However, equilibrium control is lost to internal disruptions due to the development of giant sawteeth on the 1 second time scale. This time scale is approximately the central energy confinement time, while the central particle confinement time is much longer than 1 second. This persistent limitation is present in ohmic and ICRF heated discharges. MHD stable current profiles have been found using DCON(A.H. Glasser, private communication) but transport related phenomena like giant sawteeth and uncontrolled transport barrier evolution are not yet part of a simple stability study. We are advocating avoiding the evolution of giant sawtooth and conditions responsible for MHD instabilities as opposed to exploring their stabilization. This is equivalent to the statement that self-organized plasmas are in fact not welcome in long pulse tokamaks. We intend to prevent self-organization by the application of a multi-faceted ICRF strategy. The in house technology is ready but the approach needs to be artful and not preconceived. The flexibility built into the ET hardware is likely to help us to find a way to achieve global plasma control. It is essential that this work be pursued geared towards parameter performance and configuration control. Both require a significant commitment to understanding the device physics AND delivering on the engineering required for control and performance.

Taylor, R. J.; Carter, T. A.; Gauvreau, J.-L.; Gourdain, P.-A.; Grossman, A.; Lafonteese, D. J.; Pace, D. C.; Schmitz, L. W.

2003-10-01

129

Inertial Fusion and High-Energy-Density Science in the United States.  

National Technical Information Service (NTIS)

Inertial fusion and high-energy density science worldwide is poised to take a great leap forward. In the US, programs at the University of Rochester, Sandia National Laboratories, Los Alamos National Laboratory, Lawrence Livermore National Laboratory (LLN...

C. B. Tarter

2001-01-01

130

High-temperature thermochemical water splitting cycle fusion reactor design considerations  

Microsoft Academic Search

The design considerations were explored for the adaptation of the high-temperature General Atomic sulfur-iodine thermochemical water splitting cycle to a fusion reactor heat source. This high-temperature cycle modification was found to have a good heat line match to the fusion heat source with an attractive possibility of process simplification compared to the reference HTGR-adapted cycle. The cost improvement due to

E. T. Cheng; C. P. C. Wong; K. H. McCorkle Jr.; P. W. Trester; K. R. Schultz

1980-01-01

131

The High-Yield Lithium-Injection Fusion-Energy (HYLIFE)-II inertial fusion energy (IFE) power plant concept and implications for IFE  

Microsoft Academic Search

In the High-Yield Lithium-Injection Fusion-Energy (HYLIFE) power plant design, lithium is replaced by molten salt. HYLIFE-II [Fusion Technol. {bold 25}, 5 (1994)] is based on nonflammable, renewable-liquid-wall fusion target chambers formed with LiâBeFâ molten-salt jets, a heavy-ion driver, and single-sided illumination of indirect-drive targets. Building fusion chambers from existing materials with life-of-plant structural walls behind the liquid walls, while still

Ralph W. Moir

1995-01-01

132

The High-Yield Lithium-Injection Fusion-Energy (HYLIFE)-II inertial fusion energy (IFE) power plant concept and implications for IFE  

Microsoft Academic Search

In the High-Yield Lithium-Injection Fusion-Energy (HYLIFE) power plant design, lithium is replaced by molten salt. HYLIFE-II [Fusion Technol. 25, 5 (1994)] is based on nonflammable, renewable-liquid-wall fusion target chambers formed with Li2BeF4 molten-salt jets, a heavy-ion driver, and single-sided illumination of indirect-drive targets. Building fusion chambers from existing materials with life-of-plant structural walls behind the liquid walls, while still meeting

Ralph W. Moirt

1995-01-01

133

An analytic solution of high. beta. equilibrium in a large aspect ratio tokamak  

SciTech Connect

An analytic solution of the high {beta} ({epsilon}{bar {beta}}{sub p} {approximately} {beta}q{sup 2}/{epsilon} {much gt} 1) equilibrium of a large aspect ratio tokamak is presented. Two arbitrary flux functions, the pressure profile p({psi}) and the safety factor profile q({psi}), specify the equilibrium. The solution splits into two asymptotic regions: the core region where {psi} is a function of the major radius alone and a narrow boundary layer region adjoining the conducting wall. The solutions in the two regions are asymptotically matched to each other. For monotonic pressure profiles, the Shafranov shift is equal to the minor radius. For {beta} much bigger than one, the solution contains a region (in place of the magnetic axis) of zero magnetic field and constant pressure. At high {beta} the quantity {beta}{sub I}, which is essentially proportional to the pressure over the total current squared, is largely independent of pressure. We discuss the important ramifications of limited {beta}{sub I} for high {beta} reactors. Generalizations to shaped cross sections and hollow pressure profiles are outlined. We also consider the problem of equilibrium reconstruction in the high {beta} regime. 8 refs., 7 figs.

Cowley, S.C.; Kaw, P.K.; Kelly, R.S.; Kulsrud, R.M.

1991-03-01

134

Viral Fusion Peptides Induce Several Signal Transduction Pathway Activations That Are Essential for Interleukin10 and Beta-Interferon Production  

Microsoft Academic Search

Objectives: The deciphering of intracellular signaling pathways that are activated by the interaction between viral fusion peptides and cellular membranes are important for the understanding of both viral replication strategies and host defense mechanisms. Methods: Fusion peptides of several enveloped viruses belonging to different virus families were prepared by standard 9-fluorenylmethoxycarbonyl polyamine solid-phase synthesis and used to stimulate U937 cells

Mariateresa Vitiello; Emiliana Finamore; Annarita Falanga; Katia Raieta; Marco Cantisani; Francesco Galdiero; Carlo Pedone; Marilena Galdiero; Stefania Galdiero

2010-01-01

135

MHD analysis of high (. beta. /sub t/) disruptions in PBX (Princeton Beta Experiment)  

SciTech Connect

PBX discharges run at the lowest q and highest (..beta../sub t/) always terminated in a hard disruption. The discharges, with (..beta../sub t/) values of up to 5.5% and q-values down to 2.2, were obtained by employing large current ramps and large gas feed rates during neutral beam injection. Previous work has indicated that the achieved (..beta../sub t/)-values were consistent with the limit imposed by the n = 1 ideal external kink with a conducting wall at b/a = 2. In this work, we investigate further the validity of ideal MHD theory in explaining the low-q/sub psi/j disruptions. In particular, the character of the pre-disruption MHD activity in these low-q discharges, specifically the time scales of growth and internal and external mode structures, was compared with those determined from theoretical calculations. The results of these comparisons indicate that non-ideal effects must be considered to obtain detailed agreement between theory and experiment. 13 refs., 6 figs.

Jahns, G.L.; Chance, M.S.; Kaye, S.M.; Manickam, J.; Takahashi, H.; LeBlanc, B.; Morris, A.W.; Reusch, M.; Sesnic, S.

1987-10-01

136

Characterization of TMPRSS2-ERG fusion high-grade prostatic intraepithelial neoplasia and potential clinical implications  

PubMed Central

Purpose More than 1,300,000 prostate needle biopsies are performed annually in the U.S. with up to 16% incidence of isolated high-grade prostatic intraepithelial neoplasia (HGPIN). HGPIN has low predictive value for identifying prostate cancer (PCA) on subsequent needle biopsies in PSA screened populations. In contemporary series, PCA is detected in about 20% of repeat biopsies following a diagnosis of HGPIN. Further, discrete histological subtypes of HGPIN with clinical implication in management have not been characterized. The TMPRSS2-ERG gene fusion that has recently been described in PCA has also been demonstrated to occur in a subset of HGPIN. This may have significant clinical implications given that TMPRSS2-ERG fusion PCA is associated with a more aggressive clinical course. Experimental Design In this study we assessed a series of HGPIN lesions and paired PCA for the presence of TMPRSS2-ERG gene fusion. Results Fusion positive HGPIN was observed in 16% of the 143 number of lesions, and in all instances the matching cancer shared the same fusion pattern. 60% of TMPRSS2-ERG fusion PCA had fusion negative HGPIN. Conclusions Given the more aggressive nature of TMPRSS2-ERG PCA, the findings of this study raise the possibility that gene fusion positive HGPIN lesions are harbingers of more aggressive disease. To date, pathological, molecular and clinical parameters do not help stratify which men with HGPIN are at increased risk for a cancer diagnosis. Our results suggest that the detection of isolated TMPRSS2-ERG fusion HGPIN would improve the positive predictive value of finding TMPRSS2-ERG fusion PCA in subsequent biopsies.

Mosquera, Juan-Miguel; Perner, Sven; Genega, Elizabeth M; Sanda, Martin; Hofer, Matthias D.; Mertz, Kirsten D.; Paris, Pamela L.; Simko, Jeff; Bismar, Tarek A.; Ayala, Gustavo; Shah, Rajal B.; Loda, Massimo; Rubin, Mark A.

2013-01-01

137

Fusion reactor high vacuum pumping: charcoal cryosorber tritium exposure results  

Microsoft Academic Search

Recent experiments have shown the practicality of using activated carbon (coconut charcoal) at 4 K to pump helium and hydrogen isotopes for a fusion reactor. The long-term effects of tritium on the charcoal\\/cement system developed by Grumman and LLNL was not known; therefore, a program was undertaken to see what, if any, effect long-term tritium exposure has on the cryosorber.

Douglas W. Sedgley; Charles R. Walthers; Everett M. Jenkins

1991-01-01

138

Role of high l values in the onset of incomplete fusion  

Microsoft Academic Search

A particle--coincidence experiment is performed to investigate the role of high l values in the production of direct--emitting channels (associated with incomplete fusion) in ¹²C+¹Tm system. Spin distributions of various xn\\/pxn\\/xn\\/2xn channels are measured at E{sub lab}=5.6A and 6.5A MeV. Entirely different de-excitation patterns are observed in direct--emitting channels and fusion-evaporation channels. The fusion-evaporation channels are found to be strongly

Pushpendra P. Singh; Abhishek Yadav; Devendra P. Singh; Unnati Gupta; D. Singh; M. A. Ansari; B. P. Singh; R. Prasad; Manoj K. Sharma; R. Kumar; R. P. Singh; S. Muralithar; R. K. Bhowmik

2009-01-01

139

Role of high l values in the onset of incomplete fusion  

Microsoft Academic Search

A particle-gamma-coincidence experiment is performed to investigate the role of high l values in the production of direct-alpha-emitting channels (associated with incomplete fusion) in C12+Tm169 system. Spin distributions of various xn\\/pxn\\/alphaxn\\/2alphaxn channels are measured at Elab=5.6A and 6.5A MeV. Entirely different de-excitation patterns are observed in direct-alpha-emitting channels and fusion-evaporation channels. The fusion-evaporation channels are found to be strongly fed

Pushpendra P. Singh; Abhishek Yadav; Devendra P. Singh; Unnati Gupta; Manoj K. Sharma; R. Kumar; D. Singh; R. P. Singh; S. Muralithar; M. A. Ansari; B. P. Singh; R. Prasad; R. K. Bhowmik

2009-01-01

140

Micro-engineered first wall tungsten armor for high average power laser fusion energy systems  

Microsoft Academic Search

The high average power laser program is developing an inertial fusion energy demonstration power reactor with a solid first wall chamber. The first wall (FW) will be subject to high energy density radiation and high doses of high energy helium implantation. Tungsten has been identified as the candidate material for a FW armor. The fundamental concern is long term thermo-mechanical

Shahram Sharafat; Nasr M. Ghoniem; Michael Anderson; Brian Williams; Jake Blanchard; Lance Snead

2005-01-01

141

[Beta amyloid in blood and cerebrospinal fluid is associated with high density lipoproteins].  

PubMed

Cerebrovascular and parenchymal amyloid deposits found in brains of Alzheimer's disease, Down's syndrome and normal aging are mainly composed of aggregated amyloid beta protein (A beta), a unique peptide 39 to 44 amino acids long. A similar but soluble A beta (s A beta) has been identified in plasma, cerebrospinal fluid (CSF) and cell supernatants, indicating that it is a normal protein. We report here that s A beta in normal human plasma and CSF is complexed to high density lipoprotein (HDL) 3 and very high density lipoprotein (VHDL). Biotinylated synthetic peptide A beta 1-40 was traced in normal human plasma in in vitro experiments. Both tracer biotin-labeled A beta 1-40 and native s A beta were specifically recovered in HDL3 and VHDL as it was assessed in immunoprecipitation experiments of purified plasma lipoproteins and lipoprotein depleted plasma. This fact prompted us to ascertain whether the interaction of s A beta with HDL does occur in normal human CSF in vivo. For this purpose normals human CSF was fractionated by means of sequential flotation ultracentrifugation. The presence of s A beta in the resulting lipoprotein fractions as well as in the lipoprotein depleted CSF was analysed by immunoblot analysis, electron and immune-electron microscopy and native size exclusion chromatography. Immunoblot analysis with 6E10 monoclonal anti-A beta antibodies revealed s A beta association with all HDL subspecies of CSF, primarily HDL3 and VHDL and immunoelectron microscopy confirmed an association of s A beta with CSF-HDL particles of 16.8 + 3.2 nm. Native size exclusion chromatography followed by immunoblot analysis with antibodies against A beta and different apoliproproteins indicated an association of s A beta with HDL complexes of approximately 200 kDa molecular weight. Soluble A beta association with HDL3 and VHDL may be involved in maintaining the solubility of A beta in biological fluids and points to a possible role of lipoproteins and lipoprotein lipid in the biology of aminoloidogenic peptides. PMID:9139461

Kudinova, N V; Kudinov, A R; Berezov, T T

142

Repetitively pulsed, high energy KrF lasers for inertial fusion energy  

Microsoft Academic Search

Krypton fluoride (KrF) lasers produce highly uniform beams at 248 nm, allow the capability of 'zooming' the spot size to follow an imploding pellet, naturally assume a modular architecture and have been developed into a pulsed-power-based industrial technology that readily scales to a fusion power plant sized system. There are two main challenges for the fusion power plant application: to

M. C. Myers; J. D. Sethian; J. L. Giuliani; R. Lehmberg; P. Kepple; M. F. Wolford; F. Hegeler; M. Friedman; T. C. Jones; S. B. Swanekamp; D. Weidenheimer; D. Rose

2004-01-01

143

A conceptual fusion reactor based on the high-plasma-density Z-pinch  

Microsoft Academic Search

Conceptual DT and DD fusion reactors are discussed based on magnetic confinement with the high-plasma-density Z-pinch. The reactor concepts have no 'first wall', the fusion neutrons and plasma energy being absorbed directly into a surrounding lithium vortex blanket. Efficient systems with low recirculated power are projected, based on a flow-through pinch cycle for which overall Q values can approach 10.

C. W. Hartman; G. Carlson; M. Hoffman; R. Werner; D. Y. Cheng

1977-01-01

144

Resistive wall stabilization of high-beta plasmas in DIII D  

Microsoft Academic Search

Recent DIII D experiments show that ideal kink-modes can be stabilized at high beta by a resistive wall, with sufficient plasma rotation. However, the resonant response to static magnetic field asymmetries by a marginally stable resistive wall mode can lead to strong damping of the rotation. Careful reduction of such asymmetries has allowed plasmas with beta well above the ideal

E. J. Strait; J. Bialek; N. Bogatu; M. Chance; M. S. Chu; D. Edgell; A. M. Garofalo; G. L. Jackson; T. H. Jensen; L. C. Johnson; J. S. Kim; R. J. La Haye; G. Navratil; M. Okabayashi; H. Reimerdes; J. T. Scoville; A. D. Turnbull; M. L. Walker

2003-01-01

145

Pressure-driven sound turbulence in a high-. beta. plasma  

SciTech Connect

In a large laboratory plasma (1 m diam{times}2 m, {ital n}{sub {ital e}}{le}10{sup 12} cm{sup {minus}3}, {beta}{sub 0}{approx equal}15 G, {beta}{sub {ital e}}={ital nkT}{sub {ital e}}/({beta}{sub 0}{sup 2}/2{mu}{sub 0}){approx equal}0.5), strong density fluctuations ({delta}{ital n}/{ital n}{approx equal}50%) near the lower hybrid frequency ({omega}{sub {ital c}{ital e}}{omega}{sub {ital c}{ital i}}){sup 1/2} are identified as cross-field sound waves ({ital k}{sub {perpendicular}}{much gt}{ital k}{sub {parallel}}, {omega}/{ital k}{sub {perpendicular}}{approx equal}{ital c}{sub {ital s}}) driven unstable by the electron diamagnetic drift {bold v}{sub {ital d}}={del}{ital p}{times}{bold B}/{ital ne}{beta}{sup 2}, {ital v}{sub {ital d}}{gt}{ital c}{sub {ital s}}. Wave steepening and refraction saturate the instability. Wave-enhanced transport but insignificant particle acceleration are observed.

Stenzel, R.L. (Department of Physics, University of California, Los Angeles, CA (USA))

1990-12-10

146

Satellite image fusion based on principal component analysis and high-pass filtering.  

PubMed

This paper presents an integrated method for the fusion of satellite images. Several commercial earth observation satellites carry dual-resolution sensors, which provide high spatial resolution or simply high-resolution (HR) panchromatic (pan) images and low-resolution (LR) multi-spectral (MS) images. Image fusion methods are therefore required to integrate a high-spectral-resolution MS image with a high-spatial-resolution pan image to produce a pan-sharpened image with high spectral and spatial resolutions. Some image fusion methods such as the intensity, hue, and saturation (IHS) method, the principal component analysis (PCA) method, and the Brovey transform (BT) method provide HR MS images, but with low spectral quality. Another family of image fusion methods, such as the high-pass-filtering (HPF) method, operates on the basis of the injection of high frequency components from the HR pan image into the MS image. This family of methods provides less spectral distortion. In this paper, we propose the integration of the PCA method and the HPF method to provide a pan-sharpened MS image with superior spatial resolution and less spectral distortion. The experimental results show that the proposed fusion method retains the spectral characteristics of the MS image and, at the same time, improves the spatial resolution of the pan-sharpened image. PMID:20508708

Metwalli, Mohamed R; Nasr, Ayman H; Allah, Osama S Farag; El-Rabaie, S; Abd El-Samie, Fathi E

2010-06-01

147

The high-density Z-pinch as a pulsed fusion neutron source for fusion nuclear technology and materials testing  

SciTech Connect

The dense Z-pinch (DZP) is one of the earliest and simplest plasma heating and confinement schemes. Recent experimental advances based on plasma initiation from hair-like (10s ..mu..m in radius) solid hydrogen filaments have so far not encountered the usually devastating MHD instabilities that plagued early DZP experiments. These encouraging results along with debt of a number of proof-of principle, high-current (1--2 MA in 10--100 ns) experiments have prompted consideration of the DZP as a pulsed source of DT fusion neutrons of sufficient strength (/dot S//sub N/ greater than or equal to 10/sup 19/ n/s) to provide uncollided neutron fluxes in excess of I/sub ..omega../ = 5--10 MW/m/sup 2/ over test volumes of 10--30 litre or greater. While this neutron source would be pulsed (100s ns pulse widths, 10--100 Hz pulse rate), giving flux time compressions in the range 10/sup 5/--10/sup 6/, its simplicity, near-time feasibility, low cost, high-Q operation, and relevance to fusion systems that may provide a pulsed commercial end-product (e.g., inertial confinement or the DZP itself) together create the impetus for preliminary considerations as a neutron source for fusion nuclear technology and materials testings. The results of a preliminary parametric systems study (focusing primarily on physics issues), conceptual design, and cost versus performance analyses are presented. The DZP promises an expensive and efficient means to provide pulsed DT neutrons at an average rate in excess of 10/sup 19/ n/s, with neutron currents I/sub ..omega../ /approx lt/ 10 MW/m/sup 2/ over volumes V/sub exp/ greater than or equal to 30 litre using single-pulse technologies that differ little from those being used in present-day experiments. 34 refs., 17 figs., 6 tabs.

Krakowski, R.A.; Sethian, J.D.; Hagenson, R.L.

1989-01-01

148

Microfluidic device for high-yield pairing and fusion of stem cells with somatic cells  

NASA Astrophysics Data System (ADS)

Electro cell fusion has significant potential as a biotechnology tool with applications ranging from antibody production to cellular reprogramming. However due to low fusion efficiency of the conventional electro fusion methodology the true potential of the technique has not been reached. In this paper, we report a new method which takes cell fusion efficiency two orders magnitude higher than the conventional electro fusion method. The new method, based on one-toone pairing, fusion and selection of fused cells was developed using a microfabricated device. The device was composed of two microfluidic channels, a micro slit array and a petri dish integrated with electrodes. The electrodes positioned in each channel were used to generate electric field lines concentrating in the micro slits. Cells were introduced into channels and brought in to contact through the micro slit array using dielectrophoresis. The cells in contact were fused by applying a DC pulse to electrodes. As the electric field lines were concentrated at the micro slits the membrane potential was induced only at the vicinity of the micro slits, namely only at the cell-cell contact point. This mechanism assured the minimum damage to cells in the fusion as well as the ability to control the strength and location of induced membrane potential. We introduced mouse embryonic stem cells and mouse embryonic fibroblasts to the microfluidic channels and demonstrated high-yield fusion (> 80%). Post-fusion study showed the method can generate viable hybrids of stem cells and embryonic fibroblasts. Multinucleated hybrid cells adhering on the chip surface were routinely obtained by using this method and on-chip culturing.

Gel, Murat; Hirano, Kunio; Oana, Hidehiro; Kotera, Hidetoshi; Tada, Takashi; Washizu, Masao

2011-12-01

149

A Worldwide Analysis of Beta-Defensin Copy Number Variation Suggests Recent Selection of a High-Expressing DEFB103 Gene Copy in East Asia  

PubMed Central

Beta-defensins are a family of multifunctional genes with roles in defense against pathogens, reproduction, and pigmentation. In humans, six beta-defensin genes are clustered in a repeated region which is copy-number variable (CNV) as a block, with a diploid copy number between 1 and 12. The role in host defense makes the evolutionary history of this CNV particularly interesting, because morbidity due to infectious disease is likely to have been an important selective force in human evolution, and to have varied between geographical locations. Here, we show CNV of the beta-defensin region in chimpanzees, and identify a beta-defensin block in the human lineage that contains rapidly evolving noncoding regulatory sequences. We also show that variation at one of these rapidly evolving sequences affects expression levels and cytokine responsiveness of DEFB103, a key inhibitor of influenza virus fusion at the cell surface. A worldwide analysis of beta-defensin CNV in 67 populations shows an unusually high frequency of high-DEFB103-expressing copies in East Asia, the geographical origin of historical and modern influenza epidemics, possibly as a result of selection for increased resistance to influenza in this region. Hum Mutat 32:743–750, 2011. © 2011 Wiley-Liss, Inc.

Hardwick, Robert J; Machado, Lee R; Zuccherato, Luciana W; Antolinos, Suzanne; Xue, Yali; Shawa, Nyambura; Gilman, Robert H; Cabrera, Lilia; Berg, Douglas E; Tyler-Smith, Chris; Kelly, Paul; Tarazona-Santos, Eduardo; Hollox, Edward J

2011-01-01

150

Topologically Heterogeneous Beta Cell Adaptation in Response to High-Fat Diet in Mice  

PubMed Central

Aims Beta cells adapt to an increased insulin demand by enhancing insulin secretion via increased beta cell function and/or increased beta cell number. While morphological and functional heterogeneity between individual islets exists, it is unknown whether regional differences in beta cell adaptation occur. Therefore we investigated beta cell adaptation throughout the pancreas in a model of high-fat diet (HFD)-induced insulin resistance in mice. Methods C57BL/6J mice were fed a HFD to induce insulin resistance, or control diet for 6 weeks. The pancreas was divided in a duodenal (DR), gastric (GR) and splenic (SR) region and taken for either histology or islet isolation. The capacity of untreated islets from the three regions to adapt in an extrapancreatic location was assessed by transplantation under the kidney capsule of streptozotocin-treated mice. Results SR islets showed 70% increased beta cell proliferation after HFD, whereas no significant increase was found in DR and GR islets. Furthermore, isolated SR islets showed twofold enhanced glucose-induced insulin secretion after HFD, as compared with DR and GR islets. In contrast, transplantation of islets isolated from the three regions to an extrapancreatic location in diabetic mice led to a similar decrease in hyperglycemia and no difference in beta cell proliferation. Conclusions HFD-induced insulin resistance leads to topologically heterogeneous beta cell adaptation and is most prominent in the splenic region of the pancreas. This topological heterogeneity in beta cell adaptation appears to result from extrinsic factors present in the islet microenvironment.

Ellenbroek, Johanne H.; Tons, Hendrica A.; de Graaf, Natascha; Loomans, Cindy J.; Engelse, Marten A.; Vrolijk, Hans; Voshol, Peter J.; Rabelink, Ton J.; Carlotti, Francoise; de Koning, Eelco J.

2013-01-01

151

Physics and optimization of beta beams: From low to very high gamma  

SciTech Connect

The physics potential of beta beams is investigated from low to very high gamma values and it is compared to superbeams and neutrino factories. The gamma factor and the baseline are treated as continuous variables in the optimization of the beta beam, while a fixed mass water Cherenkov detector or a totally active scintillator detector is assumed. We include in our discussion also the gamma dependence of the number of ion decays per year. For low gamma, we find that a beta beam could be a very interesting alternative to a superbeam upgrade, especially if it is operated at the second oscillation maximum to reduce correlations and degeneracies. For high gamma, we find that a beta beam could have a potential similar to a neutrino factory. In all cases, the sensitivity of the beta beams to CP violation is very impressive if similar neutrino and antineutrino event rates can be achieved.

Huber, Patrick [Department of Physics, University of Wisconsin, 1150 University Avenue, Madison, Wisconsin 53706 (United States); Lindner, Manfred; Rolinec, Mark [Physik-Department, Technische Universitaet Muenchen, James-Franck-Strasse, 85748 Garching (Germany); Winter, Walter [School of Natural Sciences, Institute for Advanced Study, Einstein Drive, Princeton, New Jersey 08540 (United States)

2006-03-01

152

Acceleration of neon pellets to high speeds for fusion applications  

SciTech Connect

The injection of impurity pellets into the plasmas of tokamak fusion reactors has been proposed as a technique to lessen the deleterious effects of plasma disruptions. Equipment and techniques that were previously developed for pneumatic hydrogen pellet injection systems and used for plasma fueling applications were employed for a limited experimental study with neon pellets. Isotopic hydrogen pellets doped with neon have previously been used for injection into fusion plasmas to study impurity particle transport, and pure neon pellets are applicable for disruption studies. Using a repeating pneumatic injector in the laboratory, it was found that the formation and acceleration of 2.7-mm-diam neon pellets were relatively straightforward; reliable operation was demonstrated with both a single- and a two-stage light gas gun, including velocities of {approximately}700 m/s with a single-stage injector and up to 1740 m/s with a two-stage injector. Based on the operating sequences and successful tests demonstrated in the laboratory experiments, a three-barrel repeating pneumatic injector installed on the DIII-D tokamak was equipped with the necessary components for neon operation and has been used in initial disruption experiments with 1.8-mm-diam neon pellets. {copyright} {ital 1996 American Institute of Physics.}

Combs, S.K.; Love, T.L.; Jernigan, T.C.; Milora, S.L. [Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831-8071 (United States); Frattolillo, A.; Migliori, S. [ENEA, Centro Ricerche Energia Frascati, Frascati, Rome (Italy)

1996-03-01

153

High Beta Steady State Research and Future Directions on JT-60U and JFT-2M  

NASA Astrophysics Data System (ADS)

JT-60U and JFT-2M research is focused on high beta steady state operation towards economically and environmentally attractive reactors. In JT-60U, a high-?p H-mode plasma was sustained with ?N 2.7 for 7.4 s in which neoclassical tearing modes (NTMs) limited the attainable ?_N. Real-time tracking NTM stabilization system using ECCD demonstrated complete suppression of NTM leading to recovery of ?N before onset of NTM. Performance in a fully non-inductive H-mode plasma was improved up to n_i(0) ?E T_i(0) = 3.1 x 10^20 keV s m-3 using N-NBCD with ?N 2.4, HH_y,2=1.2 and bootstrap fraction f_BS 0.5. ECH experiments extended the confinement enhancement for dominantly electron heated reversed shear plasmas up to HH_y,2 2 at T_e/Ti 1.25. A world record ECCD efficiency, 4.2 x 10^18 A/W/m^2, was achieved at Te 23 keV with a highly localized central current density. Innovative initiation and current build-up without center solenoid currents were established by LHCD/ECH and bootstrap current up to f_BS 0.9. In JFT-2M, the inside of the vacuum vessel wall was fully covered with low-activation ferritic steel plates to investigate their use in plasmas near fusion conditions. High ?N plasmas were produced up to ?N = 3.3 with an internal transport barrier (ITB) and a steady H-mode edge. A new H-mode regime with steady high recycling (HRS) and an ITB was exploited leading to ?N H_89P 6.2 at n_e/nG 0.7. In 2003, JT-60U will be able to operate for the duration up to 65 s at 1 MA/2.7 T and the heating/current-drive duration up to 30 s at 17 MW to prolong high-?N and/or high-f_BS discharges with feedback controls. JFT-2M is planning to implement wall stabilization experiments in 2004 to pursue plasmas above the ideal no-wall limit using a ferritic wall. The modification of JT-60 to a fully superconducting tokamak is under discussion to explore high-? steady state operation in collision-less plasmas well above no-wall limit with ferritic wall in a steady state.

Ishida, Shinichi

2003-10-01

154

Ion temperature anisotropy limitation in high beta plasmas  

SciTech Connect

Measurements of parallel and perpendicular ion temperatures in the Large Experiment on Instabilities and Anisotropies (LEIA) space simulation chamber display an inverse correlation between the upper bound on the ion temperature anisotropy and the parallel ion beta ({beta}=8{pi}nkT/B{sup 2}). Fluctuation measurements indicate the presence of low frequency, transverse, electromagnetic waves with wave numbers and frequencies that are consistent with predictions for Alfven Ion Cyclotron instabilities. These observations are also consistent with in situ spacecraft measurements in the Earth's magnetosheath and with a theoretical/computational model that predicts that such an upper bound on the ion temperature anisotropy is imposed by scattering from enhanced fluctuations due to growth of the Alfven ion cyclotron instability. (c) 2000 American Institute of Physics.

Scime, Earl E. [West Virginia University, Morgantown, West Virginia 26506 (United States); Keiter, Paul A. [West Virginia University, Morgantown, West Virginia 26506 (United States); Balkey, Matthew M. [West Virginia University, Morgantown, West Virginia 26506 (United States); Boivin, Robert F. [West Virginia University, Morgantown, West Virginia 26506 (United States); Kline, John L. [West Virginia University, Morgantown, West Virginia 26506 (United States); Blackburn, Melanie [West Virginia University, Morgantown, West Virginia 26506 (United States); Gary, S. Peter [Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States)

2000-05-01

155

Interaction of high-energy trapped particles with ballooning modes in a tokamak with a high-. beta. plasma  

SciTech Connect

A theory is derived for the interaction of high-energy trapped particleswith ballooning modes in a tokamak with a high-..beta.. plasma. A dispersionrelation is derived to describe the ballooning modes in the presence ofsuch particles; the effects of the high plasma ..beta.. are taken into account.The stability boundary for ballooning modes with zero and finite frequenciesis studied. The effects of finite bananas on the stability of ballooningmodes with zero frequencies are determined.

Mikhailovskii, A. B.; Novakovaskii, S. V.; Smolyakov, A. I.

1988-12-01

156

Magnetic fusion with high energy self-colliding ion beams  

SciTech Connect

Field-reversed configurations of energetic large orbit ions with neutralizing electrons have been proposed as the basis of a fusion reactor. Vlasov equilibria consisting of a ring or an annulus have been investigated. A stability analysis has been carried out for a long thin layer of energetic ions in a low density background plasma. There is a growing body of experimental evidence from tokamaks that energetic ions slow down and diffuse in accordance with classical theory in the presence of large non-thermal fluctuations and anomalous transport of low energy (10 keV) ions. Provided that major instabilities are under control, it seems likely that the design of a reactor featuring energetic self-colliding ion beams can be based on classical theory. In this case a confinement system that is much better than a tokamak is possible. Several methods are described for creating field reversed configurations with intense neutralized ion beams.

Rostoker, N.; Wessel, F. [California Univ., Irvine, CA (United States); Maglich, B. [Advanced Physics Corp., Irvine, CA (United States); Fisher, A. [Naval Research Lab., Washington, DC (United States)

1992-06-01

157

Development of high field superconductors for fusion energy applications  

NASA Astrophysics Data System (ADS)

The purpose of this project was to develop a conductor design and a manufacturing procedure for a composite multifilamentary Nb3Sn conductor suitable for winding a magnet for use in a fusion energy power plant. Effort was concentrated on the design of a conductor with tubular niobium filaments in a copper matrix. Bronze in the bores of the filaments would react with the niobium to form Nb3Sn on the inside diameter of the niobium tubular filaments during a heat treatment at final size. Four filament geometries were evaluated. The addition of titanium to the bronze was found to increase the current density. The use of a hydrogen atmosphere did not appear to cause any increase in current density. Primary billets were assembled and extruded with five tubular filament designs and for comparison, five rod type filament designs. Billet designs are described.

1985-09-01

158

Electromagnetic drift instabilities in high-beta plasma under conditions of a field reversed configuration  

SciTech Connect

Electromagnetic drift instabilities are studied in the conditions of a field reversed configuration (FRC). Dispersion equation is based on the set of Vlasov-Maxwell equations taking into account nonadiabatic responses both of ions and electrons. Considered drift instabilities are caused by density and temperature gradients. It is assumed that magnetic field of the FRC is purely poloidal. Two kinds of magnetic field nonuniformity are considered: (i) perpendicular gradient due to high beta values (beta is the plasma pressure/magnetic pressure) and (ii) curvature of magnetic lines. There is low frequency drift instability existing for high-beta regimes. Modes of such instability can propagate transversally to the unperturbed magnetic field lines.

Chirkov, A. Yu.; Khvesyuk, V. I. [Bauman Moscow State Technical University, 2-nd Baumanskaya, 5, Moscow 105005 (Russian Federation)

2010-01-15

159

Role of high l values in the onset of incomplete fusion  

SciTech Connect

A particle-{gamma}-coincidence experiment is performed to investigate the role of high l values in the production of direct-{alpha}-emitting channels (associated with incomplete fusion) in {sup 12}C+{sup 169}Tm system. Spin distributions of various xn/pxn/{alpha}xn/2{alpha}xn channels are measured at E{sub lab}=5.6A and 6.5A MeV. Entirely different de-excitation patterns are observed in direct-{alpha}-emitting channels and fusion-evaporation channels. The fusion-evaporation channels are found to be strongly fed over a broad spin range. While narrow range feeding for only high-spin states was observed in the case of direct-{alpha}-emitting channels, in the present work, incomplete fusion is shown to be a promising tool to populate high-spin states in final reaction products. To have better insight into the associated l values in different reaction channels, the present data are compared with similar data obtained in {sup 16}O(E{sub lab}{approx_equal}5.6A MeV) + {sup 169}Tm system. The mean driving angular momenta involved in the production of direct-{alpha}-emitting channels are found to be higher than those involved in the production of fusion-evaporation channels. Direct-{alpha} multiplicity in the forward cone increases with driving angular momenta, which indicates the origin of direct-{alpha}-emitting channels at high l values in noncentral interactions.

Singh, Pushpendra P. [INFN - Laboratori Nazionali di Legnaro, I-35020 Legnaro (Italy); Yadav, Abhishek; Singh, Devendra P.; Gupta, Unnati; Singh, D.; Ansari, M. A.; Singh, B. P.; Prasad, R. [Accelerator Laboratory, Department of Physics, A. M. University, Aligarh 202 002 (India); Sharma, Manoj K. [Physics Department, S. V. College, Aligarh 202 001 (India); Kumar, R.; Singh, R. P.; Muralithar, S.; Bhowmik, R. K. [NP-Group, Inter-University Accelerator Center, New Delhi 110 067 (India)

2009-12-15

160

High-level expression of recombinant human FK-binding protein from a fusion precursor.  

PubMed

The human peptidyl-prolyl isomerase FK-binding protein (FKBP) was cloned as a fusion partner with CMP-KDO synthetase (CKS), and the resultant construct was characterized as an improved high-expression source for FKBP. The CKS-FKBP fusion was expressed as a soluble protein at levels approaching 1 gm/L in Escherichia coli fermentations. The fusion protein was purified to near homogeneity by a one-step ammonium sulfate fractionation of whole cell lysate. After selective cleavage, the fusion precursor produced yields approaching 300 mg of purified FKBP per liter of harvested culture, a approximately 30 to 60-fold increase over that observed for a nonfusion construct. Selective cleavage of the fusion partners was accomplished using either hydroxylamine or specific, limited proteolysis. Once separated from the CKS fusion partner, the FKBP was isolated in a single step by either reversed-phase HPLC or chromatography on Q-Sepharose. For comparison of physical and chemical properties, a nonfusion construct of recombinant human FKBP was expressed in E. coli and isolated. The purified FKBPs exhibited expected SDS-PAGE molecular weights and N-terminal sequences. The proteins had similar proton NMR spectra and binding to [3H]FK-506. The fusion construct, CKS-FKBP, was also found to bind [3H]FK-506. These data indicate that FKBP fused to the C-terminus of CKS folds independently of the fusion partner and suggests the fused FKBP adopts a conformation resembling that of the native protein. PMID:1382438

Edalji, R; Pilot-Matias, T J; Pratt, S D; Egan, D A; Severin, J M; Gubbins, E G; Petros, A M; Fesik, S W; Burres, N S; Holzman, T F

1992-06-01

161

Plasma confinement of Nagoya high-beta toroidal-pinch experiments  

Microsoft Academic Search

Two different types of high-beta toroidal pinch experiments, STP and CCT, have been done to study the confinement of the plasma produced by a theta-pinch. The STP is an axisymmetric toroidal pinch of high-beta Tokamak type, while the CCT consists of multiply connected periodic toroidal traps. Internal current-carrying copper rings are essential to the CCT. In the STP experiment, strong

K. Hirano; S. Kitagawa; M. Wakatani; Y. Kita; S. Yamada; S. Yamaguchi; K. Sato; T. Aizawa; Y. Osanai; N. Noda

1977-01-01

162

High heat flux components—Readiness to proceed from near term fusion systems to power plants  

Microsoft Academic Search

A present topic of high interest in magnetic fusion is the “gap” between near-term and long-term concepts for high heat flux components (HHFC), and in particular for divertors. This paper focuses on this issue with the aim of characterizing the international status of current HHFC design concepts for ITER and describing the different technologies needed in the designs being developed

A. R. Raffray; R. Nygren; D. G. Whyte; S. Abdel-Khalik; R. Doerner; F. Escourbiac; T. Evans; R. J. Goldston; D. T. Hoelzer; S. Konishi; P. Lorenzetto; M. Merola; R. Neu; P. Norajitra; R. A. Pitts; M. Rieth; M. Roedig; T. Rognlien; S. Suzuki; M. S. Tillack; C. Wong

2010-01-01

163

High current ion sources and injectors for induction linacs in heavy ion fusion  

Microsoft Academic Search

Heavy ion beam driven inertial fusion requires short ion beam pulses with high current and high brightness. Depending on the beam current and the number of beams in the driver system, the injector can use a large diameter surface ionization source or merge an array of small beamlets from a plasma source. In this paper, we review the scaling laws

Joe W. Kwan

2005-01-01

164

Technical assessment of thermal-hydraulics for high heat flux fusion components  

Microsoft Academic Search

A technical assessment of three possible thermal-hydraulic high heat flux (HHF) heat removal techniques which will result in adequate heat removal from fusion components with minimum penalty is presented. The heat removal alternatives discussed are: (1) subcooled flow boiling (SFB) with water; (2) high velocity helium gas convection (HGC); and (3) liquid metal (LM) heat transfer in the presence of

R. D. Boyd; C. P. C. Wong; Y. S. Cha

1985-01-01

165

Resonant magnetohydrodynamic waves in high-beta plasmas  

SciTech Connect

When a global magnetohydrodynamic (MHD) wave propagates in a weakly dissipative inhomogeneous plasma, the resonant interaction of this wave with either local Alfven or slow MHD waves is possible. This interaction occurs at the resonant position where the phase velocity of the global wave coincides with the phase velocity of either Alfven or slow MHD waves. As a result of this interaction a dissipative layer embracing the resonant position is formed, its thickness being proportional to R{sup -1/3}, where R>>1 is the Reynolds number. The wave motion in the resonant layer is characterized by large amplitudes and large gradients. The presence of large gradients causes strong dissipation of the global wave even in very weakly dissipative plasmas. Very often the global wave motion is characterized by the presence of both Alfven and slow resonances. In plasmas with small or moderate plasma beta {beta}, the resonance positions corresponding to the Alfven and slow resonances are well separated, so that the wave motion in the Alfven and slow dissipative layers embracing the Alfven and slow resonant positions, respectively, can be studied separately. However, when {beta} > or approx. R{sup 1/3}, the two resonance positions are so close that the two dissipative layers overlap. In this case, instead of two dissipative layers, there is one mixed Alfven-slow dissipative layer. In this paper the wave motion in such a mixed dissipative layer is studied. It is shown that this motion is a linear superposition of two motions, one corresponding to the Alfven and the other to the slow dissipative layer. The jump of normal velocity across the mixed dissipative layer related to the energy dissipation rate is equal to the sum of two jumps, one that occurs across the Alfven dissipative layer and the other across the slow dissipative layer.

Ruderman, M. S. [Department of Applied Mathematics, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH (United Kingdom)

2009-04-15

166

High-Energy Beta Decay of Light Elements  

Microsoft Academic Search

The beta decay of the radioactive members of the mass-eight and -twelve triads has been studied with a spiral-orbit spectrometer having a 1.3% resolution. The end point, half-life and log-ft values respectively are: for N¹², 16.37 {+-} 0.06 MeV, 11.43 {+-} 0.05 milliseconds, and 4.17; for B¹², 13.40 {+-} 0.05 MeV, 20.6 {+-} 0.2 msec and 4.11; for B⁸, 14

Vedder; James F

1958-01-01

167

Formation of high-{beta} plasma and stable confinement of toroidal electron plasma in Ring Trap 1  

SciTech Connect

Formation of high-{beta} electron cyclotron resonance heating plasma and stable confinement of pure electron plasma have been realized in the Ring Trap 1 device, a magnetospheric configuration generated by a levitated dipole field magnet. The effects of coil levitation resulted in drastic improvements of the confinement properties, and the maximum local {beta} value has exceeded 70%. Hot electrons are major component of electron populations, and its particle confinement time is 0.5 s. Plasma has a peaked density profile in strong field region [H. Saitoh et al., 23rd IAEA Fusion Energy Conference EXC/9-4Rb (2010)]. In pure electron plasma experiment, inward particle diffusion is realized, and electrons are stably trapped for more than 300 s. When the plasma is in turbulent state during beam injection, plasma flow has a shear, which activates the diocotron (Kelvin-Helmholtz) instability. The canonical angular momentum of the particle is not conserved in this phase, realizing the radial diffusion of charged particles across closed magnetic surfaces. [Z. Yoshida et al., Phys Rev. Lett. 104, 235004 (2010); H. Saitoh et al., Phys. Plasmas 17, 112111 (2010).].

Saitoh, H.; Yoshida, Z.; Morikawa, J.; Furukawa, M.; Yano, Y.; Kawai, Y.; Kobayashi, M.; Vogel, G.; Mikami, H. [Department of Advanced Energy, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan)

2011-05-15

168

Common Fusion Transcripts Identified in Colorectal Cancer Cell Lines by High-Throughput RNA Sequencing12  

PubMed Central

Colorectal cancer (CRC) is the third most common cancer disease in the Western world, and about 40% of the patients die from this disease. The cancer cells are commonly genetically unstable, but only a few low-frequency recurrent fusion genes have so far been reported for this disease. In this study, we present a thorough search for novel fusion transcripts in CRC using high-throughput RNA sequencing. From altogether 220 million paired-end sequence reads from seven CRC cell lines, we identified 3391 candidate fused transcripts. By stringent requirements, we nominated 11 candidate fusion transcripts for further experimental validation, of which 10 were positive by reverse transcription-polymerase chain reaction and Sanger sequencing. Six were intrachromosomal fusion transcripts, and interestingly, three of these, AKAP13-PDE8A, COMMD10-AP3S1, and CTB-35F21.1-PSD2, were present in, respectively, 18, 18, and 20 of 21 analyzed cell lines and in, respectively, 18, 61, and 48 (17%-58%) of 106 primary cancer tissues. These three fusion transcripts were also detected in 2 to 4 of 14 normal colonic mucosa samples (14%–28%). Whole-genome sequencing identified a specific genomic breakpoint in COMMD10-AP3S1 and further indicates that both the COMMD10-AP3S1 and AKAP13-PDE8A fusion transcripts are due to genomic duplications in specific cell lines. In conclusion, we have identified AKAP13-PDE8A, COMMD10-AP3S1, and CTB-35F21.1-PSD2 as novel intrachromosomal fusion transcripts and the most highly recurring chimeric transcripts described for CRC to date. The functional and clinical relevance of these chimeric RNA molecules remains to be elucidated.

Nome, Torfinn; Thomassen, Gard OS; Bruun, Jarle; Ahlquist, Terje; Bakken, Anne C; Hoff, Andreas M; Rognum, Torleiv; Nesbakken, Arild; Lorenz, Susanne; Sun, Jinchang; Barros-Silva, Joao Diogo; Lind, Guro E; Myklebost, Ola; Teixeira, Manuel R; Meza-Zepeda, Leonardo A; Lothe, Ragnhild A; Skotheim, Rolf I

2013-01-01

169

International Stellarator/Heliotron Database progress on high-beta confinement and operational boundaries  

SciTech Connect

he International Stellarator/Heliotron Confinement Database was extended by high-beta data compiled from the Large Helical System (LHD) and the W7-AS Stellarator. The main purpose is to enhance the basis for extrapolation of the global confinement properties to the reactor regime. The high-beta configurations and experimental achievements in both devices are briefly described. The impact of beta on the configuration parameters and the global confinement is discussed. In particular, the confinement data in the high-beta regime are compared with the ISS95 and ISS04 scaling laws which were derived from a database including relatively few high-beta cases. In addition, a Bayesian model comparison approach is used to test scaling predictions derived from basic confinement models. Unlike in tokamaks, the operational boundaries in stellarators and helical systems are determined by the available heating power and confinement properties rather than by disruptive stability or density limits. The role of a pressure induced equilibrium limit is discussed in particular. An attempt is made to compare the high-beta data with tokamak confinement and with operational boundaries observed in tokamaks. Further extensions of the database by parameters characterizing stability and local transport properties are proposed.

Weller, A. [Max-Planck-Institute for Plasmaphysik, EURATOM-Association, Greifswald, Germany; Watanabe, K. Y. [National Institute for Fusion Science, Toki, Japan; Sakakibara, S. [National Institute for Fusion Science, Toki, Japan; Dinklage, A. [Max-Planck-Institute for Plasmaphysik, EURATOM-Association, Greifswald, Germany; Funaba, H. [National Institute for Fusion Science, Toki, Japan; Geiger, J. [Max-Planck-Institute for Plasmaphysik, EURATOM-Association, Greifswald, Germany; Harris, Jeffrey H [ORNL; Ohdachi, S. [National Institute for Fusion Science, Toki, Japan; Preuss, R. [Max-Planck-Institute for Plasmaphysik, EURATOM-Association, Greifswald, Germany; Suzuki, Y. [National Institute for Fusion Science, Toki, Japan; Werner, A. [Max-Planck-Institute for Plasmaphysik, EURATOM-Association, Greifswald, Germany; Yamada, H. [National Institute for Fusion Science, Toki, Japan; Zarnstorff, M. C. [Princeton Plasma Physics Laboratory (PPPL)

2009-01-01

170

Aqueous environmental crack propagation in high-strength beta titanium alloys  

SciTech Connect

The aqueous environment-assisted cracking (EAC) behavior of two peak-aged beta-titanium was characterized with a fracture mechanics method. Beta-21S is susceptible to EAC under rising load in neutral 3.5 pct NaCi at 25 C and {minus}600 mV{sub SCE}, as indicated by a reduced threshold for subcritical crack growth (K{sub TH}), an average crack growth rate of up to 10 {mu}m s, and intergranular fracture compared to microvoid rupture in air. In contrast, the initiation fracture toughness (K{sub ICi}) of Ti-15-3 in moist air is lower than that of Beta-21S at similar high {sigma}{sub YS} (1,300 MPa) but is not degraded by chloride, and cracking is by transgranular microvoid formation. The intergranular EAC susceptibility of Beta-21S correlates with both {alpha}-colonies precipitated at {beta} grain boundaries and intense slip localization; however, the causal factor is not defined. Data suggest that both features, and EAC, are promoted by prolonged solution treatment at high temperature. In a hydrogen environment embrittlement (HEE) scenario, crack-tip H could be transported by planar slip bands to strongly binding trap sites and stress/strain concentrations at {alpha} colony or {beta} grain boundaries. The EAC in Beta-21S is eliminated by cathodic polarization (to {minus}1,000 mV{sub SCE}), as well as by static loading for times that otherwise produce rising-load EAC.

Young, L.M. [General Electric Corporate Research and Development Center, Schenectady, NY (United States); Young, G.A. Jr. [Knolls Atomic Power Lab., Schenectady, NY (United States); Scully, J.R.; Gangloff, R.P. [Univ. of Virginia, Charlottesville, VA (United States)

1995-05-01

171

High-Yield Lithium-Injection Fusion-Energy (HYLIFE) reactor  

SciTech Connect

The High-Yield Lithium-Injection Fusion Energy (HYLIFE) concept to convent inertial confinement fusion energy into electric power has undergone intensive research and refinement at LLNL since 1978. This paper reports on the final HYLIFE design, focusing on five major areas: the HYLIFE reaction chamber (which includes neutronics, liquid-metal jet-array hydrocynamics, and structural design), supporting systems, primary steam system and balance of plant, safety and environmental protection, and costs. An annotated bibliography of reports applicable to HYLIFE is also provided. We conclude that HYLIFE is a particularly viable concept for the safe, clean production of electrical energy. The liquid-metal jet array, HYLIFE's key design feature, protects the surrounding structural components from x-rays, fusion fuel-pellet debris, neutron damage and activation, and high temperatures and stresses, allowing the structure to last for the plant's entire 30-year lifetime without being replaced. 127 refs., 18 figs.

Blink, J.A.; Hogam, W.J.; Hovingh, J.; Meier, E.R.; Pitts, J.H. (comps.)

1985-12-23

172

The National Ignition Facility - Applications for Inertial Fusion Energy and High Energy Density Science  

SciTech Connect

Over the past several decades, significant and steady progress has been made in the development of fusion energy and its associated technology and in the understanding of the physics of high-temperature plasmas. While the demonstration of net fusion energy (fusion energy production exceeding that required to heat and confine the plasma) remains a task for the next millennia and while challenges remain, this progress has significantly increased confidence that the ultimate goal of societally acceptable (e.g. cost, safety, environmental considerations including waste disposal) central power production can be achieved. This progress has been shared by the two principal approaches to controlled thermonuclear fusion--magnetic confinement (MFE) and inertial confinement (ICF). ICF, the focus of this article, is complementary and symbiotic to MFE. As shown, ICF invokes spherical implosion of the fuel to achieve high density, pressures, and temperatures, inertially confining the plasma for times sufficient long (t {approx} 10{sup -10} sec) that {approx} 30% of the fuel undergoes thermonuclear fusion.

Campbell, E.M.; Hogan, W.J.

1999-08-12

173

Diagnosing the High Energy Deuterium Spectra in IEC Devices Using Doppler Shifted Fusion Products  

NASA Astrophysics Data System (ADS)

The UW-Inertial Electrostatic Confinement (IEC) device is comprised of concentric spherical metallic grids within a cylindrical vacuum vessel. The central grid, which can be held at high negative potentials (˜ -100 to -200kV), is the device cathode, while the outer grid, held at ground potential, is the device anode. This configuration accelerates ions, created near the anode, toward the center of the device. A weakly ionized cold plasma, created by a filament assisted DC discharge outside the anode, is the ion source for the device. The fill gas for this device is typically deuterium, thus leading to D-D fusion rates on the order of 10^8 fusions/s. The high energy protons and tritons resultant from D-D fusion reactions have been observed using charged particle detectors. These detectors are capable of discerning the Doppler shift on D-D fusion products imparted by the center of mass energy of the deuterium reactants. From the fusion product spectra compiled by a multi-channel analyzer the energy spectra of the deuterium reactants can be calculated. Using this diagnostic the effect, on the deuterium spectra, of varying the parameters of fill gas pressure, cathode voltage, cathode current and grid geometry have been examined.

Boris, David

2008-11-01

174

Remarks on detecting high-energy deuterium–tritium fusion gamma rays using a gas Cherenkov detector  

Microsoft Academic Search

As fusion ignition conditions are approached using the national ignition facility (NIF), independent high-bandwidth gamma-ray fusion burn measurements become essential complements to information obtained from neutron diagnostics. The 16.75-MeV gamma rays that accompany deuterium–tritium (d+t) fusion can be detected using a high-bandwidth gaseous carbon dioxide Cherenkov threshold detector. The detection energy threshold was set by the CO2 gas pressure. A

J. M. Mack; R. R. Berggren; S. E. Caldwell; C. R. Christensen; S. C. Evans; J. R. Faulkner Jr.; R. L. Griffith; G. M. Hale; R. S. King; D. K. Lash; R. A. Lerche; J. A. Oertel; D. M. Pacheco; C. S. Young

2006-01-01

175

In vivo formation of gene fusions encoding hybrid beta-galactosidase proteins in one step with a transposable Mu-lac transducing phage.  

PubMed Central

A Mu-lac bacteriophage transposon, MudII301 (Ap, lac), was constructed to form hybrid protein gene fusions. When it integrates into structural genes in the appropriate direction and reading phase, transcription and translation from outside gene controlling regions can proceed across 116 nucleotides from the right end of Mu into lacZ codons to form hybrid proteins that are enzymatically active for beta-galactosidase. Integration can be obtained either by infection to form lysogens or by transposition during growth of a lysogen. The size of the hybrid protein product either corresponds to or, in the cases of translation restart or protein degradation, is a minimal estimate of the distance of the Mu insertion from the translation initiation site of the gene. Hybrid proteins formed by insertions in randomly selected genes and in the araB and A genes were examined by polyacrylamide gel electrophoresis. Images

Casadaban, M J; Chou, J

1984-01-01

176

High-beta plasma formation and observation of peaked density profile in RT1  

Microsoft Academic Search

High-beta ECH plasma is generated and stably sustained in a magnetospheric configuration, the Ring Trap 1 (RT-1) device, generated by a levitated dipole field magnet. Geomagnetic-field compensation and optimized operation have realized drastic improvements in plasma properties. The maximum local beta value has reached 70% and the pressure profiles have a rather steep gradient near the superconducting magnet. Electrons of

H. Saitoh; Z. Yoshida; J. Morikawa; Y. Yano; T. Mizushima; Y. Ogawa; M. Furukawa; Y. Kawai; K. Harima; Y. Kawazura; Y. Kaneko; K. Tadachi; S. Emoto; M. Kobayashi; T. Sugiura; G. Vogel

2011-01-01

177

Engineering of beta-propeller protein scaffolds by multiple gene duplication and fusion of an idealized WD repeat.  

PubMed

The ability to design specific amino acid sequences that fold into desired structures is central to engineering novel proteins. Protein design is also a good method to assess our understanding of sequence-structure and structure-function relationships. While beta-sheet structures are important elements of protein architecture, it has traditionally been more difficult to design beta-proteins than alpha-helical proteins. Taking advantage of the tandem repeated sequences that form the structural building blocks in a group of beta-propeller proteins; we have used a consensus design approach to engineer modular and relatively large scaffolds. An idealized WD repeat was designed from a structure-based sequence alignment with a set of structural guidelines. Using a plasmid sequential ligation strategy, artificial concatemeric genes with up to 10 copies of this idealized repeat were then constructed. Corresponding proteins with 4 through to 10 WD repeats were soluble when over-expressed in Escherichia coli. Notably, they were sufficiently stable in vivo surviving attack from endogenous proteases, and maintained a homogeneous, non-aggregated form in vitro. The results show that the beta-propeller scaffold is an attractive platform for future engineering work, particularly in experiments in which directed evolution techniques might improve the stability of the molecules and/or tailor them for a specific function. PMID:16651025

Nikkhah, Maryam; Jawad-Alami, Zahra; Demydchuk, Mykhaylo; Ribbons, Duncan; Paoli, Massimo

2006-05-02

178

Cold fusion: Alchemist's dream  

NASA Astrophysics Data System (ADS)

In this report the following topics relating to cold fusion are discussed: muon catalyzed cold fusion; piezonuclear fusion; sundry explanations pertaining to cold fusion; cosmic ray muon catalyzed cold fusion; vibrational mechanisms in excited states of D2 molecules; barrier penetration probabilities within the hydrogenated metal lattice/piezonuclear fusion; branching ratios of D2 fusion at low energies; fusion of deuterons into He-4; secondary D+T fusion within the hydrogenated metal lattice; helium-3 to helium-4 ratio within the metal lattice; shock induced fusion; and anomalously high isotopic ratios of helium-3/helium-4.

Clayton, E. D.

1989-09-01

179

Analysis of Ballooning Instability for Ultra High Beta Spherical Tokamaks in TS-3 Merging Experiment  

NASA Astrophysics Data System (ADS)

We have been investigating ultra-high beta characteristics of spherical tokamaks (ST) produced by merging and reconnection techniques of TS-3 ST/CT experiment[1]. Ballooning mode was found the most dangerous instability for the STs with volume-averaged beta value over 50formation, they were observed to stay stably or to collapse due to high-n mode activities, depending on their pressure and current profiles. The BALOO code[2] analyses of the experimentally obtained high-beta ST equilibria, clarified the conditions to reach the second stable region and to attain higher beta value. Their critical beta value was found to increase with localizing the pressure gradient and the poloidai current at the edge. When the plasma parameters reached at the second stable region, the critical beta value increased sharply. Using the BALOO code and experimentally obtained current/ pressure profiles, we are now studying effect of aspect ratio on the ballooning instability to conclude whether we can make realistic reactor design of second-stable STs. [1] Y. Ono et al., Phys. Plasmas 7, 1863 (2000), [2]R. L. Miller et al. Phys. Plasma 4, 1092 (1997).

Kimura, T.; Miyazaki, S.; Umeda, K.; Ogawa, T.; Ueda, Y.; Ono, Y.; Katsurai, M.

2002-11-01

180

Structure of a high-pressure phase of vanadium pentoxide, beta-V2O5.  

PubMed

A high-pressure phase of vanadium pentoxide, denoted beta-V2O5, has been prepared at P = 6.0 GPa and T = 1073 K. The crystal structure of beta-V2O5 has been studied by X-ray and neutron powder diffraction, and high-resolution transmission electron microscopy. The V atoms are six-coordinated within distorted VO6 octahedra. The structure is built up of quadruple units of edge-sharing VO6 octahedra linked by sharing edges along [010] and mutually connected by sharing corners along [001]. This arrangement forms layers of V4O10 composition in planes parallel to (100). The layers are mutually held together by weak forces. beta-V2O5 is metastable and transforms to alpha-V2O5 at 643-653 K under ambient pressure. Structural relationships between beta- and alpha-V2O5, and between beta-V2O5 and B-Ta2O5-type structures are discussed. The high-pressure beta-V2O5 layer structure can be considered as the parent of a new series of vanadium oxide bronzes with cations intercalated between the layers. PMID:15258395

Filonenko, V P; Sundberg, M; Werner, P-E; Zibrov, I P

2004-07-19

181

Anthrax Toxin Uptake by Primary Immune Cells as Determined with a Lethal Factor-beta-Lactamase Fusion Protein  

Microsoft Academic Search

BackgroundTo initiate infection, Bacillus anthracis needs to overcome the host innate immune system. Anthrax toxin, a major virulence factor of B. anthracis, impairs both the innate and adaptive immune systems and is important in the establishment of anthrax infections.Methodology\\/Principal FindingsTo measure the ability of anthrax toxin to target immune cells, studies were performed using a fusion of the anthrax toxin

Haijing Hu; Stephen H. Leppla; Adam J. Ratner

2009-01-01

182

High current density beamlets from a rf argon source for heavy ion fusion applications  

NASA Astrophysics Data System (ADS)

In a new approach to develop high current beams for heavy ion fusion, beam current at about 0.5 ampere per channel can be obtained by merging an array of high current density beamlets of 5 mA each. We have done computer simulations to study the transport of high current density beamlets and the emittance growth due to this merging process. In our radio frequency (rf) multicusp source experiment, we have produced a cluster of 61 beamlets using minimum gas flow. The current density from a 0.25 cm diameter aperture reached 100 mA/cm2. The normalized 4 rms emittance of 0.0186? mm mrad corresponds to an equivalent ion temperature of 2.08 eV. These results showed that the rf argon plasma source is suitable for producing high current density beamlets that can be merged to form a high current high brightness beam for heavy ion fusion application.

Kwan, J. W.; Grote, D. P.; Westenskow, G. A.

2004-05-01

183

A U.S. high-flux neutron facility for fusion materials development  

SciTech Connect

Materials for a fusion reactor first wall and blanket structure must be able to reliably function in an extreme environment that includes 10-15 MW-year/m{sup 2} neutron and heat fluences. The various materials and structural challenges are as difficult and important as achieving a burning plasma. Overcoming radiation damage degradation is the rate-controlling step in fusion materials development. Recent advances with oxide dispersion strengthened ferritic steels show promise in meeting reactor requirements, while multi-timescale atomistic simulations of defect-grain boundary interactions in model copper systems reveal surprising self-annealing phenomenon. While these results are promising, simultaneous evaluation of radiation effects displacement damage ({le} 200 dpa) and in-situ He generation ({le} 2000 appm) at prototypical reactor temperatures and chemical environments is still required. There is currently no experimental facility in the U.S. that can meet these requirements for macroscopic samples. The E.U. and U.S. fusion communities have recently concluded that a fusion-relevant, high-flux neutron source for accelerated characterization of the effects of radiation damage to materials is a top priority for the next decade. Data from this source will be needed to validate designs for the multi-$B next-generation fusion facilities such as the CTF, ETF, and DEMO, that are envisioned to follow ITER and NIF.

Rei, Donald J [Los Alamos National Laboratory

2010-01-01

184

Study Of High-Spin States In 48Ca Region Induced By Secondary Fusion Reactions  

NASA Astrophysics Data System (ADS)

A new method of in-beam gamma-ray spectroscopy induced by secondary fusion reactions, 37P+9Be and 46Ar+9Be is presented. Low-energy secondary beams of 37P and 46Ar ions of ~5 MeV/A were developed in order to induce fusion evaporation reactions. Excited states of nuclei in the vicinity of 48Ca, 49-52Ti and 46Ca, were studied by the method as well as ? decay of the secondary beam 46Ar. Gamma-gamma coincidence and excitation function analysis were performed to study high-spin states of Ti isotopes.

Ideguchi, E.; Niikura, M.; Ishida, C.; Fukuchi, T.; Baba, H.; Hokoiwa, N.; Iwasaki, H.; Koike, T.; Komatsubara, T.; Kubo, T.; Kurokawa, M.; Michimasa, S.; Miyakawa, K.; Morimoto, K.; Ohnishi, T.; Ota, S.; Ozawa, A.; Shimoura, S.; Suda, T.; Tamaki, M.; Tanihata, I.; Wakabayashi, Y.; Yoshida, K.; Cederwall, B.

2005-04-01

185

Hyperspectral and high-resolution image fusion based on second generation Bandelet transform  

NASA Astrophysics Data System (ADS)

A fusion algorithm of hyperspectral and high-resolution images based on principal component analysis (PCA) and second generation Bandelet transform is proposed. Primarily, the numerous components of the hyperspectral image are divided. Subsequently, the maximum rule is used to select the Bandelet coefficients and geometry flows of the hyperspectral image which are transformed by PCA in the following step. Finally, the fused image is reconstructed by taking inverse PCA and Bandelet transform. Some numerical simulations are made to test the validity and capability of the proposed fusion algorithm.

Du, Xiaoping; Chen, Hang; Liu, Zhengjun; Dou, Xiaojie; Xia, Lurui; Cheng, Xiangzhen; Shan, Congmiao

2013-06-01

186

High heat flux issues for plasma-facing components in fusion reactors  

Microsoft Academic Search

Plasma facing components in tokamak fusion reactors are faced with a number of difficult high heat flux issues. These components include: first wall armor tiles, pumped limiters, diverter plates, rf antennae structure, and diagnostic probes. Peak heat fluxes are 15 - 30 MW\\/m2 for diverter plates, which will operate for 100 - 1000 seconds in future tokamaks. Disruption heat fluxes

Robert D. Watson

1993-01-01

187

Development of High Performance Nb3Sn Conductor for Fusion and Accelerator Applications  

Microsoft Academic Search

While the highest field performance is a primary goal of the conductor in the next generation of particle accelerators, emphasis has been focused mainly on the increase in current carrying capacity. The conductor needed for fusion application, however, requires much lower magnetization limit along with a critical current as high as possible. The upgraded strand specifications for the International Thermonuclear

Taeyoung Pyon; Jukka Somerkoski; Hem Kanithi; Ben Karlemo; Mikael Holm

2007-01-01

188

The National Ignition Facility Status and Plans for Laser Fusion and High Energy Density Experimental Studies  

Microsoft Academic Search

The National Ignition Facility (NIF) currently under construction at the University of California Lawrence Livermore National Laboratory is 192-beam, 1.8 Megajoule, 500 Terawatt, 351 nm laser for inertial confinement fusion and high energy density experimental studies. NIF is being built by the Department of Energy and the National Nuclear Security Agency to provide an experimental test bed for the US

Craig R. Wuest

2001-01-01

189

Final technical report. 1998 HU CFRT summer fusion high school workshop  

SciTech Connect

The center conducted its third High School Summer Fusion Science Workshop in Summer 1998. The center had only three faculty mentors available only for a part of Summer 1998, The center accepted four scholars in this workshop, Prof. Halima Ali coordinated this workshop. Each student was assigned to a research mentor according to the student's interest in a specific research area and problem. In the workshop in the center, the students received instructions and training in the basics of energy, plasma and fusion sciences. They also received one-on-one instructions and training by their mentors to further their understanding of the subject and to introduce to relevant concepts such as magnetic confinement fusion, tokamaks, diverters and area-preserving maps.

Ali, Halima; Punjabi, Alkesh

1999-07-01

190

MICRO-HETEROGENEITY AND MICRO-RHEOLOGICAL PROPERTIES OF HIGH-VISCOSITY OAT BETA-GLUCAN SOLUTIONS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Soluble fiber beta-glucan is one of the key dietary materials in the healthy food products known for reducing serum cholesterol levels. However, the physical properties of beta-glucan are rarely known. In this work, the micro-structural heterogeneity and micro-rheology of high-viscosity oat beta-g...

191

In vivo expression of GLP-1/IgG-Fc fusion protein enhances beta-cell mass and protects against streptozotocin-induced diabetes.  

PubMed

Glucagon-like peptide 1 (GLP-1) and its analogue exendin-4 (Ex4) have displayed potent glucose homeostasis-modulating characteristics in type 2 diabetes (T2D). However, there are few reports of effectiveness in type 1 diabetes (T1D) therapy, where there is massive loss of beta cells. We previously described a novel GLP-1 analogue consisting of the fusion of active GLP-1 and IgG heavy chain constant regions (GLP-1/IgG-Fc), and showed that in vivo expression of the protein, via electroporation-enhanced intramuscular plasmid-based gene transfer, normalized blood glucose levels in T2D-prone db/db mice. In the present study, GLP-1/IgG-Fc and Ex4/IgG-Fc were independently tested in multiple low-dose streptozotocin-induced T1D. Both GLP-1/IgG-Fc and Ex4/IgG-Fc effectively reduced fed blood glucose levels in treated mice and ameliorated diabetes symptoms, where as control IgG-Fc had no effect. Treatment with GLP-1/IgG-Fc or Ex4/IgG-Fc improved glucose tolerance and increased circulating insulin and GLP-1 levels. It also significantly enhanced islet beta-cell mass, which is likely a major factor in the amelioration of diabetes. This suggests that GLP-1/IgG-Fc gene therapy may be applicable to diseases where there is either acute or chronic beta-cell injury. PMID:17410180

Soltani, N; Kumar, M; Glinka, Y; Prud'homme, G J; Wang, Q

2007-04-05

192

High-Damage-Threshold Pinhole for Glass Fusion Laser Applications  

SciTech Connect

We are investigating methods to fabricate high-damage-threshold spatial-filter pinholes that might not be susceptible to plasma closure for relatively high energies and long pulses. These are based on the observation that grazing-incidence reflection from glass can withstand in excess of 5 kJ/cm{sup 2} (normal to the beam) without plasma formation. The high damage threshold results from both the cos q spreading of the energy across the surface and the reflection of a large fraction of the energy from the surface, thereby greatly reducing the field strength within the medium.

Kumit, N.A.; Letzring, S.A.; Johnson, R.P.

1998-06-07

193

Production and stability of high-beta DIII-D discharges with reversed magnetic shear  

SciTech Connect

Plasma configurations with reversed magnetic shear have been proposed for steady-state tokamak operation since the plasma profiles can be made consistent with good confinement, high bootstrap current fraction, and stability at very high beta. The stability of reversed magnetic shear discharges with beta up to 11% has previously been demonstrated in DIII-D. Reversed magnetic shear (RMS) refers to a safety factor profile, q({rho}), which is a non-monotonic function of minor radius, {rho}. The magnetic shear S {equivalent_to} ({rho}/q) dq/d{rho} is negative within the plasma core and positive at the edge. When S < 0, short wavelength ballooning modes are stable, and the toroidal current density peaks near the radius of minimum safety factor, q{sub min}. This off-axis current maximum can be aligned, with the non-inductive bootstrap current generated by the pressure gradient, reducing the requirements for external current drive. Stabilization of long wavelength external kink modes at high beta requires a nearby conducting wall, and this effect has been demonstrated in DIII-D experiments. In this paper, the authors describe high confinement and high beta DIII-D discharges having strongly reversed magnetic shear. These discharges differ from previously reported RMS plasmas since high-quality measurements of the internal magnetic field now permit clear documentation of the central shear reversal region in high beta plasmas with enhanced confinement. Additionally, these RMS discharges are produced in DIII-D with power plant-relevant ion temperatures T{sub i}(0) up to 20 keV, at Troyon-normalized beta up to 4, high central safety factor with q(0) often exceeding 10 while q{sub min} {approximately} 2, and with or without the improved edge confinement characteristic of H-mode operation.

Mauel, M.E. [Columbia Univ., New York, NY (United States). Dept. of Applied Physics; Rice, B.W. [Lawrence Livermore National Lab., CA (United States); Strait, E.J. [General Atomics, San Diego, CA (United States)] [and others

1995-07-01

194

Spiroborate ester-mediated asymmetric synthesis of beta-hydroxy ethers and its conversion to highly enantiopure beta-amino ethers.  

PubMed

Borane-mediated reduction of aryl and alkyl ketones with alpha-aryl- and alpha-pyridyloxy groups affords beta-hydroxy ethers in high enantiomeric purity (up to 99% ee) and in good yield, using as catalyst 10 mol % of spiroborate ester 1 derived from (S)-diphenylprolinol. Representative beta-hydroxy ethers are successfully converted to beta-amino ethers, with minor epimerization, by phthalimide substitution under Mitsunobu's conditions followed by hydrazinolysis to obtain primary amino ethers or by imide reduction with borane to afford beta-2,3-dihydro-1H-isoindol ethers. Nonracemic Mexiletine and nAChR analogues with potential biological activity are also synthesized in excellent yield by mesylation of key beta-hydroxy pyridylethers and substitution with five-, six-, and seven-membered ring heterocyclic amines. PMID:19413288

Huang, Kun; Ortiz-Marciales, Margarita; Correa, Wildeliz; Pomales, Edgardo; López, Xaira Y

2009-06-01

195

Mice lacking neuronal nicotinic acetylcholine receptor beta4-subunit and mice lacking both alpha5- and beta4-subunits are highly resistant to nicotine-induced seizures.  

PubMed

Nicotine, the main addictive component of tobacco, evokes a wide range of dose-dependent behaviors in rodents, and when administrated in high doses, it can induce clonic-tonic seizures. Nicotine acts through the nicotinic acetylcholine receptors (nAChRs). Mutations in the human alpha4- and the beta2-nAChR subunit genes cause autosomal dominant nocturnal frontal lobe epilepsy. Using transgenic mice with mutations in nAChR subunits, it was demonstrated previously that the alpha4-, alpha5-, and alpha7-subunits are involved in nicotine-induced seizures. To examine the possibility that the beta4-subunit is also involved in this phenotype, we tested mice with homozygous beta4-subunit deficiency. The beta4 null mice were remarkably resistant to nicotine-induced seizures compared with wild-type and alpha5 null mice. We also generated mice with double deficiency of both alpha5- and beta4-nAChR subunits and demonstrated that they were more resistant to nicotine's convulsant effect than either the alpha5 or the beta4 single mutant mice. In addition, the single alpha5 mutants and the double alpha5beta4-deficient mice exhibited a significantly shorter latency time to seizure than that of the wild-type mice. Our results thus show that beta4-containing nAChRs have a crucial role in the pathogenesis of nicotine-induced seizures. Furthermore, by comparing multiple mutant mice with single and double subunit deficiency, we suggest that nicotinic receptors containing either alpha5- or beta4-subunits are involved in nicotine-induced seizures and that receptors containing both subunits are likely to contribute to this phenomena as well. However, the alpha5-subunit, but not the beta4-subunit, regulates the rate of response to high doses of nicotine. PMID:14996991

Kedmi, Merav; Beaudet, Arthur L; Orr-Urtreger, Avi

2004-04-13

196

Contribution of Neutron Beta Decay to Radiation Belt Pumping from High Altitude Nuclear Explosion  

Microsoft Academic Search

In 1962, several satellites were lost following high altitude nuclear tests by the United States and the Soviet Union. These satellite failures were caused by energetic electrons injected into the earth's radiation belts from the beta decay of bomb produced fission fragments and neutrons. It has been 40 years since the last high altitude nuclear test; there are now many

Marrs

2002-01-01

197

Effects of global MHD instability on operational high beta-regime in LHD  

Microsoft Academic Search

In the Large Helical Device (LHD), the highest operational averaged beta value has been expanded from 3.2% to 4% in the last 2 years by increasing the heating capability and exploring a new magnetic configuration with a high aspect ratio. Although the magneto-hydrodynamic (MHD) stability properties are considered to be unfavourable in the new high aspect configuration, the heating efficiency

K. Y. Watanabe; S. Sakakibara; Y. Narushima; H. Funaba; K. Narihara; K. Tanaka; T. Yamaguchi; K. Toi; S. Ohdachi; O. Kaneko; H. Yamada; Y. Suzuki; W. A. Cooper; S. Murakami; N. Nakajima; I. Yamada; K. Kawahata; T. Tokuzawa; A. Komori

2005-01-01

198

Thermal and structural design aspects of high-temperature blankets for fusion synfuel production  

SciTech Connect

The most promising process, high temperature electrolysis (HTE) of steam at temperatures of greater than or equal to 1000/sup 0/C is examined. In HTE, a large fraction (up to approx. 50%) of the energy input to split water to hydrogen and oxygen comes from thermal energy. For the projected operating conditions achieved by high temperature fusion blankets, overall efficiencies for hydrogen production should be on the order of 60%. The design, thermal-hydraulics, and materials for such blankets are discussed.

Powell, J.R.; Fillo, J.A.; Reich, M.

1981-01-01

199

High yield inertial confinement fusion target design for a z-pinch-driven hohlraum  

Microsoft Academic Search

Calculations are presented for a high yield inertial fusion design, employing indirect drive with a double-ended z-pinch-driven hohlraum radiation source. A high current (?60 MA) accelerator implodes z pinches within an enclosing hohlraum. Radial spoke arrays and shine shields isolate the capsule from the pinch plasma, magnetic field, and direct x-ray shine. Our approach places minimal requirements on z-pinch uniformity

James H. Hammer; Max Tabak; Scott C. Wilks; John D. Lindl; David S. Bailey; Peter W. Rambo; Arthur Toor; George B. Zimmerman; John L. Porter

1999-01-01

200

High yield inertial confinement fusion target design for a z-pinch-driven hohlraum  

Microsoft Academic Search

Calculations are presented for a high yield inertial fusion design, employing indirect drive with a double-ended z-pinch-driven hohlraum radiation source. A high current (~60 MA) accelerator implodes z pinches within an enclosing hohlraum. Radial spoke arrays and shine shields isolate the capsule from the pinch plasma, magnetic field, and direct x-ray shine. Our approach places minimal requirements on z-pinch uniformity

James H. Hammer; Max Tabak; Scott C. Wilks; John D. Lindl; David S. Bailey; Peter W. Rambo; Arthur Toor; George B. Zimmerman; John L. Porter

1999-01-01

201

Forest type classification using data fusion of multispectral and panchromatic high-resolution satellite imageries  

Microsoft Academic Search

This paper proposes fusion analysis of high-resolution multispectral and panchromatic satellite imageries for forest type classification. We have shown the performance of forest type classification using panchromatic and multispectral high-resolution QuickBird satellite imageries separately. With texture features obtained from a panchromatic imagery, forest was classified into two types, such as coniferous and broad-leaved forests. On the other hand, with spectral

Naoko Kosaka; Tsuyoshi Akiyama; Bien Tsai; Toshiharu Kojima

2005-01-01

202

Aspects and Reaction Rates for Pycnonuclear Fusion at High Densities  

Microsoft Academic Search

Pycnonuclear reactions are of great importance in the nuclear astrophysics of high density conditions such as the centers of white dwarf starts, and the deep layers of accreting neutron stars. We present here a single phenomenological expression for the calculation of pycnonuclear reaction rates which is not only valid in mixed component plasma, but can also be extended to cover

Mary Beard; Michael Wiescher; Anatoli Afanasjev; Leandro Gasques; Dima Yakovlev

2008-01-01

203

High frequency fusion of plant protoplasts by electric fields  

Microsoft Academic Search

Mesophyll cell protoplasts of Vicia faba were collected by dielectrophoresis in a highly inhomogeneous alternating electric field (sine wave, 5 to 10 V peak-to-peak value, 500 kHz, electrode distance 200 µm). Under these conditions, the cells formed aggregates of two or three on the electrodes or bridges consisting of 4 to 6 protoplasts between the electrodes. This “pearl chain” arrangement

U. Zimmermann; P. Scheurich

1981-01-01

204

Options for integrated beam experiments for inertial fusion energy and high-energy density physics research  

NASA Astrophysics Data System (ADS)

The Heavy Ion Fusion Virtual National Laboratory (HIF-VNL), a collaboration among LBNL, LLNL, and PPPL, is presently focused on separate smaller-scale scientific experiments addressing key issues of future Inertial Fusion Energy (IFE) and High-Energy-Density-Physics (HEDP) drivers: the injection, transport, and focusing of intense heavy ion beams at currents from 25 to 600 mA. As a next major step in the HIF-VNL program, we aim for a fully integrated beam physics experiment, which allows integrated source-to-target physics research with a high-current heavy ion beam of IFE-relevant brightness with the goal of optimizing target focusing. This paper describes two rather different options for such an integrated experiment, the Integrated Beam Experiment (IBX) and the Neutralized Drift Compression Experiment (NDCX). Both proposals put emphasis on the unique capability for integrated injection, acceleration, compression, and focusing of a high-current, space-charge-dominated heavy ion beam.

Leitner, M. A.; Celata, C. M.; Lee, E. P.; Logan, B. G.; Waldron, W. L.; Yu, S. S.; Barnard, J. J.

2005-05-01

205

Z, ZX, and X-1: A Realistic Path to High Fusion Yield  

SciTech Connect

Z-pinches now constitute the most energetic and powerful sources of x-rays available by a large margin. The Z accelerator at Sandia National Laboratories has produced 1.8 MJ of x-ray energy, 280 TW of power, and hohlraum temperatures of 200 eV. These advances are being applied to inertial confinement fusion (ICF) experiments on Z. The requirements for high fusion yield are exemplified in the target to be driven by the X-1 accelerator. X-1 will drive two z-pinches, each producing 7 MJ of x-ray energy and about 1000 TW of x-ray power. Together, these radiation sources will heat a hohlraum containing the 4-mm diameter ICF capsule to a temperature exceeding 225 eV for about 10 ns, with the pulse shape required to drive the capsule to high fusion yield, in the range of 200--1000 MJ. Since X-1 consists of two identical accelerators, it is possible to mitigate the technical risk of high yield by constructing one accelerator. This accelerator, ZX, will bridge the gap from Z to X-1 by driving an integrated target experiment with a very efficient energy source, ZX will also provide experimental condition that the full specifications of the X-1 accelerator for high yield are achievable, and that a realistic path to high fission yield exists.

COOK, DONALD L.

1999-10-07

206

High-performance fusion of multispectral and hyperspectral data  

NASA Astrophysics Data System (ADS)

Hyperspectral imagers tend to have lower spatial resolution than multispectral ones. This often results in a (sometimes difficult) trade-off between spectral and spatial resolution. One means of addressing this spatial/spectral resolution trade-off is to acquire both multispectral and hyperspectral data simultaneously, and then combine the two to produce a hyperspectral image with the high spatial resolution of the multispectral image. This process, called 'sharpening', results in a product that fuses the rich spectral content of a hyperspectral image with the high spatial content of the multispectral image. The approach we have been investigating compares the spectral information present in the multispectral image to the spectral content in the hyperspectral image and derives a set of equations to approximately transform the multispectral image into a synthetic hyperspectral image. This synthetic hyperspectral image is then recombined with the original low-spatial-resolution hyperspectral image to produce a sharpened product. We have evaluated this technique against several types of data for terrain classification and it has demonstrated good performance across all data sets. The spectra predicted by the sharpening algorithm match truth spectra in synthetic image tests, and performance with detection algorithms show little, if any, degradation of detection performance.

Winter, Michael E.; Winter, Edwin M.; Beaven, Scott G.; Ratkowski, Anthony J.

2006-06-01

207

Modeling of High Kinetic Energy Plasma Jets for Fusion Applications  

NASA Astrophysics Data System (ADS)

We used semi-analytical models for high velocity (>200 km/s) and density (>10^17 cm-3) plasma jets to describe the acceleration in coaxial electrodes geometry, the collision, and plasma liner implosion, assuming that jets have merged into a spherical or cylindrical shell. The results are compared with experimental data and are being used for guiding LSP and MACH2 codes simulation and for optimization. The simplest model which uses the adiabatic invariant for oscillator revealed the basic relation between the velocity and the parameters of the plasma accelerator. Plasma slug model was extended for including friction and mass addition by electrode erosion. A simple model of blow-by instability by using the canting angle of the plasma current was formulated. As plasma jets collision at high interfacial Mach number generates shock fronts, we analyzed their possible consequences on the merging process and liner formation. The structure of the spherical shell liner during adiabatic implosion and the effect of the shock wave generated at void closure on the confinement time were also investigated.

Bogatu, I. N.; Galkin, S. A.; Kim, J. S.

2006-10-01

208

EDITORIAL: The Nuclear Fusion Award The Nuclear Fusion Award  

NASA Astrophysics Data System (ADS)

The Nuclear Fusion Award ceremony for 2009 and 2010 award winners was held during the 23rd IAEA Fusion Energy Conference in Daejeon. This time, both 2009 and 2010 award winners were celebrated by the IAEA and the participants of the 23rd IAEA Fusion Energy Conference. The Nuclear Fusion Award is a paper prize to acknowledge the best distinguished paper among the published papers in a particular volume of the Nuclear Fusion journal. Among the top-cited and highly-recommended papers chosen by the Editorial Board, excluding overview and review papers, and by analyzing self-citation and non-self-citation with an emphasis on non-self-citation, the Editorial Board confidentially selects ten distinguished papers as nominees for the Nuclear Fusion Award. Certificates are given to the leading authors of the Nuclear Fusion Award nominees. The final winner is selected among the ten nominees by the Nuclear Fusion Editorial Board voting confidentially. 2009 Nuclear Fusion Award nominees For the 2009 award, the papers published in the 2006 volume were assessed and the following papers were nominated, most of which are magnetic confinement experiments, theory and modeling, while one addresses inertial confinement. Sabbagh S.A. et al 2006 Resistive wall stabilized operation in rotating high beta NSTX plasmas Nucl. Fusion 46 635-44 La Haye R.J. et al 2006 Cross-machine benchmarking for ITER of neoclassical tearing mode stabilization by electron cyclotron current drive Nucl. Fusion 46 451-61 Honrubia J.J. et al 2006 Three-dimensional fast electron transport for ignition-scale inertial fusion capsules Nucl. Fusion 46 L25-8 Ido T. et al 2006 Observation of the interaction between the geodesic acoustic mode and ambient fluctuation in the JFT-2M tokamak Nucl. Fusion 46 512-20 Plyusnin V.V. et al 2006 Study of runaway electron generation during major disruptions in JET Nucl. Fusion 46 277-84 Pitts R.A. et al 2006 Far SOL ELM ion energies in JET Nucl. Fusion 46 82-98 Berk H.L. et al 2006 Explanation of the JET n = 0 chirping mode Nucl. Fusion 46 S888-97 Urano H. et al 2006 Confinement degradation with beta for ELMy HH-mode plasmas in JT-60U tokamak Nucl. Fusion 46 781-7 Izzo V.A. et al 2006 A numerical investigation of the effects of impurity penetration depth on disruption mitigation by massive high-pressure gas jet Nucl. Fusion 46 541-7 Inagaki S. et al 2006 Comparison of transient electron heat transport in LHD helical and JT-60U tokamak plasmas Nucl. Fusion 46 133-41 Watanabe T.-H. et al 2006 Velocity-space structures of distribution function in toroidal ion temperature gradient turbulence Nucl. Fusion 46 24-32 2010 Nuclear Fusion Award nominees For the 2010 award, the papers published in the 2007 volume were assessed and the following papers were nominated, all of which are magnetic confinement experiments and theory. Rice J.E. et al 2007 Inter-machine comparison of intrinsic toroidal rotation in tokamaks Nucl. Fusion 47 1618-24 Lipschultz B. et al 2007 Plasma-surface interaction, scrape-off layer and divertor physics: implications for ITER Nucl. Fusion 47 1189-205 Loarer T. et al 2007 Gas balance and fuel retention in fusion devices Nucl. Fusion 47 1112-20 Garcia O.E et al 2007 Fluctuations and transport in the TCV scrape-off layer Nucl. Fusion 47 667-76 Zonca F. et al 2007 Electron fishbones: theory and experimental evidence Nucl. Fusion 47 1588-97 Maggi C.F. et al 2007 Characteristics of the H-mode pedestal in improved confinement scenarios in ASDEX Upgrade, DIII-D, JET and JT-60U Nucl. Fusion 47 535-51 Yoshida M. et al 2007 Momentum transport and plasma rotation profile in toroidal direction in JT-60U L-mode plasmas Nucl. Fusion 47 856-63 Zohm H. et al 2007 Control of MHD instabilities by ECCD: ASDEX Upgrade results and implications for ITER Nucl. Fusion 47 228-32 Snyder P.B. et al 2007 Stability and dynamics of the edge pedestal in the low collisionality regime: physics mechanisms for steady-state ELM-free operation Nucl. Fusion 47 961-8 Urano H. et al 2007 H-mode pedestal structure in the variation of toroidal rotation and toroidal f

Kikuchi, M.

2011-01-01

209

High Temperature coatings based on {beta}-NiAI  

SciTech Connect

High temperature alloys are reviewed, focusing on current superalloys and their coatings. The synthesis, characerization, and oxidation performance of a NiAl–TiB{sub 2} composite are explained. A novel coating process for Mo–Ni–Al alloys for improved oxidation performance is examined. The cyclic oxidation performance of coated and uncoated Mo–Ni–Al alloys is discussed.

Severs, Kevin

2012-07-10

210

High-level beta-lactamase activity in sputum samples from cystic fibrosis patients during antipseudomonal treatment.  

PubMed Central

The in vivo activity and source of beta-lactamase in sputum samples from 43 patients with cystic fibrosis (CF) during a 2-week antipseudomonal treatment were studied. A colorimetric method, based on the conversion of nitrocefin, was used for quantitation of the sputum beta-lactamase activity. beta-Lactamases in sputum were characterized by isoelectric focusing and inhibition profile and were compared with the beta-lactamases extracted from Pseudomonas aeruginosa isolated from the paired sputum samples. We found that the beta-lactamase activity increased to high levels in sputum from patients with CF during the course of piperacillin, ceftazidime, cefsulodin, or imipenem therapy. Aztreonam therapy lead to opposite results because the beta-lactamase activity decreased and aztreonam was able to mask beta-lactamase activity by acting as an inhibitor. All sputum beta-lactamases displayed characteristics indicative of a class I enzyme, identical to the beta-lactamases extracted from P. aeruginosa. The presence of beta-lactamase at such levels could lead to in vivo inactivation of beta-lactam antibiotics. This study supports the hypothesis that beta-lactamase production is an important in vivo resistance mechanism in P. aeruginosa-infected patients with CF.

Giwercman, B; Meyer, C; Lambert, P A; Reinert, C; H?iby, N

1992-01-01

211

Internal hydrogen embrittlement of high-strength beta-alpha titanium alloys  

NASA Astrophysics Data System (ADS)

Potential problems and uncertainties are associated with the complex nature of fracture in solution treated and aged (STA) beta-titanium (beta-Ti) alloys, as well as the potential for long-term alloy degradation due to hydrogen embrittlement. This research characterizes the effects of predissolved hydrogen and microstructural conditions on the fracture resistance of two solution treated and aged (STA) high strength beta-titanium alloys, Low Cost Beta (LCB) and Ti-15-3, in sheet form. Rising-CMOD fracture test results demonstrate that STA beta-Ti alloys are severely embrittled at room temperature and a slow displacement rate above a relatively low threshold hydrogen concentration. Hydrogen concentrations of 400 and 500 wppm reduce the threshold stress intensity at the onset of hydrogen cracking to 50% of the air fracture toughness in STA LCB, and Ti-15-3, respectively. Significant embrittlement for both alloys is triggered at concentrations in excess of 750 wppm, with reductions in threshold stress intensity to an asymptotic value equal to 25% of the air fracture toughness. Reductions in crack growth resistance with increasing hydrogen concentrations are accompanied by significant increases in subcritical crack growth rates. Changes in fracture mode are concurrent with reduced in fracture resistance. With increasing hydrogen concentration, the fracture mode changes from microvoid coalescence to transgranular hydrogen-assisted alpha/beta interface cracking. Two mechanisms of internal hydrogen embrittlement in STA metastable beta-Ti alloys, bond decohesion and hydride formation are proposed to occur at alpha/beta interfaces. A critical isothermal aging time must be exceeded to render Ti-15-3 susceptible to internal hydrogen embrittlement. This is attributed to a critical alpha volume fraction and the associated stress and hydrogen concentration. The internal hydrogen embrittlement of STA Ti-15-3 is a time dependent phenomenon. Experimental results and crack tip strain rate calculations demonstrate that embrittlement will persist in STA Ti-15-3 to loading rates of approximately 0.5 MPa?m/s. As such, hydrogen redistribution to the crack tip is a critical component of internal hydrogen embrittlement. Local transport of hydrogen in intra-alpha beta to susceptible alpha/beta interfaces, and possibly growth kinetics of gamma-TiH2, in the fracture process zone are consistent with the observed kinetics and appear to govern the time dependence.

Hayes, Sean Paul

212

Atomic data for highly charged ions Applications to X-ray laser design and thermonuclear fusion  

NASA Astrophysics Data System (ADS)

A detailed understanding of a myriad of atomic processes is proving important for the development of short wavelength lasers and to the achievement of controlled thermonuclear fusion. A brief overview of some X-ray laser design issues is presented along with a discussion of relevant atomic data needs. Special attention is given to the need for experimental verification of rate coefficient data which are important for determining laser kinetics. Approaches to magnetic and inertial confinement fusion are reviewed with emphasis on atomic processes affecting both fuel burn and plasma diagnostics. Recent advances in the development of high power ICF drivers, both lasers and particle beams, are shown to suggest new areas of research involving very highly charged ions in dense hot plasmas.

Younger, Stephen M.

1987-04-01

213

US Heavy Ion Beam Research for High Energy Density Physics Applications and Fusion  

SciTech Connect

Key scientific results from recent experiments, modeling tools, and heavy ion accelerator research are summarized that explore ways to investigate the properties of high energy density matter in heavy-ion-driven targets, in particular, strongly-coupled plasmas at 0.01 to 0.1 times solid density for studies of warm dense matter, which is a frontier area in high energy density physics. Pursuit of these near-term objectives has resulted in many innovations that will ultimately benefit heavy ion inertial fusion energy. These include: neutralized ion beam compression and focusing, which hold the promise of greatly improving the stage between the accelerator and the target chamber in a fusion power plant; and the Pulse Line Ion Accelerator (PLIA), which may lead to compact, low-cost modular linac drivers.

Davidson, R.C.; Logan, B.G.; Barnard, J.J.; Bieniosek, F.M.; Briggs, R.J.; et al.

2005-09-19

214

"Polarized" Fusion  

NASA Astrophysics Data System (ADS)

Increasing energy demand in view of limited supply, as well as environmental and nuclear-safety concerns leading to increased emphasis on renewable energy sources such as solar or wind energy are expected to focus public and scientific interest increasingly also on fusion energy. With the decision to build ITER (low-density magnetic confinement) and also continuing research on (high-density) inertial-confinement fusion (cf. the inauguration of the laser fusion facility at the Lawrence Livermore National Laboratory) prospects of fusion energy have probably entered a new era.

Schieck, Hans Paetz Gen.

215

Spheromak path to fusion  

SciTech Connect

The spheromak attributes? - internally generated toroidal magnetic field without linked coils, dynamo-driven plasma current resulting from helicity injection, and compactness - lead to attractive reactor options ranging from ?conventional? steady-state designs, to high beta pulsed configurations, and to-the core of a Magnetized Target Fusion (MTF) device. The resolution of the physics issues associated with these attributes, discussed in later sections, will determine the size and viability of the reactors. Preliminary designs, however, have been made and illustrate the opportunities.

Hooper, E. B.; Ryutov, D. D.; Thomassen, K. I.

1999-01-05

216

The High-Yield Lithium-Injection Fusion-Energy (HYLIFE)-II inertial fusion energy (IFE) power plant concept and implications for IFE  

SciTech Connect

In the High-Yield Lithium-Injection Fusion-Energy (HYLIFE) power plant design, lithium is replaced by molten salt. HYLIFE-II [Fusion Technol. {bold 25}, 5 (1994)] is based on nonflammable, renewable-liquid-wall fusion target chambers formed with Li{sub 2}BeF{sub 4} molten-salt jets, a heavy-ion driver, and single-sided illumination of indirect-drive targets. Building fusion chambers from existing materials with life-of-plant structural walls behind the liquid walls, while still meeting non-nuclear grade construction and low-level waste requirements, has profound implications for inertial fusion energy (IFE) development. Fluid-flow work and computational fluid dynamics predict chamber clearing adequate for 6 Hz pulse rates. Predicted electricity cost is reduced about 30% to 4.4{cents}/kWh at 1 GWe and 3.2{cents}/kWh at 2 GWe. Development can be foreshortened and cost reduced by obviating expensive neutron sources to develop first-wall materials. The driver and chamber can be upgraded in stages, avoiding separate and sequential facilities. Important features of a practical IFE power plant are ignition and sufficient gain in targets; low-cost, efficient, rep-ratable driver; and low-cost targets.

Moir, R.W. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

1995-06-01

217

Open reading frame expression vectors: a general method for antigen production in Escherichia coli using protein fusions to beta-galactosidase.  

PubMed Central

We have developed an Escherichia coli plasmid vector for the identification and expression of foreign DNA segments that are open reading frames (ORFs). The 5' end of ompF, an E. coli gene encoding an abundant outer membrane protein, is used to provide a strong, regulated promoter, translation initiation site, and signal sequence for export from the cytoplasm. This sequence is coupled to the lacZ gene of E. coli so that expression of beta-galactosidase requires ompF transcription and translation signals. However, this hybrid gene is LacZ- because lacZ is out of frame with respect to ompF. Restriction enzyme recognition sites are located between ompF and lacZ to allow convenient insertion of DNA fragments. If an insert is an ORF of the correct length, ompF and lacZ become realigned in frame, resulting in a LacZ+ gene that produces a tribrid protein with the translation product of the insert sandwiched between OmpF and beta-galactosidase. The LacZ+ phenotype thus identifies clones containing an expressed ORF. To demonstrate the vector's utility we inserted a fragment from the herpes virus thymidine kinase gene and used the resulting tribrid protein to raise antibodies that precipitate thymidine kinase from herpes virus-infected cells. We also inserted a fragment from the E. coli lexA gene to produce a tribrid protein that is precipitated by antiserum raised with LexA protein. Thus, tribrid fusion proteins can be used to produce or detect antibodies and also to identify the product of a cloned gene. Images

Weinstock, G M; ap Rhys, C; Berman, M L; Hampar, B; Jackson, D; Silhavy, T J; Weisemann, J; Zweig, M

1983-01-01

218

Open reading frame expression vectors: a general method for antigen production in Escherichia coli using protein fusions to beta-galactosidase.  

PubMed

We have developed an Escherichia coli plasmid vector for the identification and expression of foreign DNA segments that are open reading frames (ORFs). The 5' end of ompF, an E. coli gene encoding an abundant outer membrane protein, is used to provide a strong, regulated promoter, translation initiation site, and signal sequence for export from the cytoplasm. This sequence is coupled to the lacZ gene of E. coli so that expression of beta-galactosidase requires ompF transcription and translation signals. However, this hybrid gene is LacZ- because lacZ is out of frame with respect to ompF. Restriction enzyme recognition sites are located between ompF and lacZ to allow convenient insertion of DNA fragments. If an insert is an ORF of the correct length, ompF and lacZ become realigned in frame, resulting in a LacZ+ gene that produces a tribrid protein with the translation product of the insert sandwiched between OmpF and beta-galactosidase. The LacZ+ phenotype thus identifies clones containing an expressed ORF. To demonstrate the vector's utility we inserted a fragment from the herpes virus thymidine kinase gene and used the resulting tribrid protein to raise antibodies that precipitate thymidine kinase from herpes virus-infected cells. We also inserted a fragment from the E. coli lexA gene to produce a tribrid protein that is precipitated by antiserum raised with LexA protein. Thus, tribrid fusion proteins can be used to produce or detect antibodies and also to identify the product of a cloned gene. PMID:6308625

Weinstock, G M; ap Rhys, C; Berman, M L; Hampar, B; Jackson, D; Silhavy, T J; Weisemann, J; Zweig, M

1983-07-01

219

Alternate applications of fusion power: development of a high-temperature blanket for synthetic-fuel production  

SciTech Connect

This study has shown that utilization of the unique features of a fusion reactor can result in a novel and potentially economical method of decomposing steam into hydrogen and oxygen. Most of the power of fusion reactors is in the form of energetic neutrons. If this power could be used to produce high temperature uncontaminated steam, a large fraction of the energy needed to decomposee the steam could be supplied as thermal energy by the fusion reaction. Proposed high temperature electrolysis processes require steam temperature in excess of 1000/sup 0/C for high efficiency. The design put forth in this study details a system that can accomplish that end.

Howard, P.A.; Mattas, R.F.; Krajcinovic, D.; DePaz, J.; Gohar, Y.

1981-11-01

220

High beta, sawtooth-free tokamak operation using energetic trapped particles  

SciTech Connect

It is shown that a population of high energy trapped particles, such as that produced by ion cyclotron heating in tokamaks, can result in a plasma completely stable to both sawtooth oscillations and the fishbone mode. The stable window of operation increases in size with plasma temperature and with trapped particle energy, and provides a means of obtaining a stable plasma with high current and high beta. 13 refs., 2 figs.

White, R.B.; Bussac, M.N.; Romanelli, F.

1988-08-01

221

High temperature surface effects of He + implantation in ICF fusion first wall materials  

Microsoft Academic Search

The first wall armor of the inertial confinement fusion reactor chambers must withstand high temperatures and significant radiation damage from target debris and neutrons. The resilience of multiple materials to one component of the target debris has been investigated using energetic (20–40keV) helium ions generated in the inertial electrostatic confinement device at the University of Wisconsin. The materials studied include:

Samuel J. Zenobia; R. F. Radel; B. B. Cipiti; Gerald L. Kulcinski

2009-01-01

222

LWR spent fuel transmutation in a high power density fusion reactor  

Microsoft Academic Search

The prospect of light water reactor (LWR) spent fuel incineration in a high power density fusion reactor has been investigated. The neutron wall load is taken at 10 MW\\/m2 and a refractory alloy (W-5Re) is used in the first wall. Neutron transport calculations are conducted over an operation period of 48 months on a simple experimental hybrid blanket in a

Sümer ?ahin; Mustafa Übeyli

2004-01-01

223

Studies in high current density ion sources for heavy ion fusion applications  

Microsoft Academic Search

This dissertation develops diverse research on small (diameter˜few mm), high current density (J˜several tens of mA\\/cm2) heavy ion sources. The research has been developed in the context of a programmatic interest within the Heavy Ion Fusion (HIF) Program to explore alternative architectures in the beam injection systems that use the merging of small, bright beams. An ion gun was designed

Edwin Chacon-Golcher

2002-01-01

224

Advanced high power gyrotrons for EC H&CD applications in fusion plasmas  

Microsoft Academic Search

Summary form only given. The R&D activities at Forschungszentrum Karlsruhe (FZK) on advanced high-power mm-wave gyrotrons for future use in electron cyclotron heating and current drive (EC H&CD) in fusion plasmas consist of: (1) the development of a coaxial cavity gyrotron capable of delivering 2 MW continuous wave (CW) at 170 GHz and (2) investigations on tunable multi-frequency gyrotrons. In

M. Thumm; A. Arnold; E. Borie; G. Dammertz; R. Heidinger; S. Illy; J. Jin; K. Koppenburg; G. Michel; B. Piosczyk; T. Rzesnicki; D. Wagner; X. Yang

2004-01-01

225

Development of a new concept ion source for high performance inertial electrostatic confinement fusion device  

Microsoft Academic Search

An Inertial Electrostatic Confinement Fusion (IECF) is a concept for retaining a plasma using an electrostatic potential well. It consists of two spherical grids inside the vacuum chamber. An insulated high voltage feed-through supplies power to the inner grid cathode, and a small amount of deuterium or tritium gas (0.1-1.0 Pa) is fed into the chamber. When the voltage is

Y. Taniuchi; Y. Matsumura; K. Taira; M. Utsumi

2010-01-01

226

PODOPHYLLUM PELTATUM POSSESSES A BETA-GLUCOSIDASE WITH HIGH SUBSTRATE SPECIFICITY FOR THE ARYLTETRALIN LIGNAN PODOPHYLLOTOXIN  

Technology Transfer Automated Retrieval System (TEKTRAN)

A beta-glucosidase with high specificity for podophyllotoxin-4-O-b-d-glucopyranoside was purified from the leaves of Podophyllum peltatum. The 65 kD polypeptide had optimum activity at pH 5.0 and was essentially inactive at physiological pH (6.5 or above). The maximum catalytic activity of this glu...

227

Comment on enhancement of forbidden nuclear beta decay by high-intensity radio-frequency fields  

Microsoft Academic Search

A recent claim that forbidden nuclear beta decay can, by the application of a high-intensity radio-frequency field, be enhanced by many orders of magnitude is contested. The effect is shown to be nonexistent, at least within the theoretical model which has been adopted thus far.

W. Becker; R. R. Schlicher; M. O. Scully

1984-01-01

228

Stability of High-beta Tokamaks with Respect to Pellet Injection.  

National Technical Information Service (NTIS)

During the course of a long pulse or steady state operation, the fuel in a plasma becomes depleted. This necessitates the refueling of the reactor. Several methods have been proposed. In this thesis the use of pellet injection in a high toroidal beta toka...

W. C. Tetley

1983-01-01

229

High resolution optical measurements of beta-layering in D-T  

SciTech Connect

An optical method is developed for the study of beta-layering of solid deuterium-tritium target capsules for the National Inertial Confinement Program. High-resolution image data show that the surface roughness do not exceed 2 micrometers 50 hours after first target freezing. (AIP) [copyright] 1994 [ital American] [ital Institute] [ital of] [ital Physics

Hoffer, J.K.; Foreman, L.R. (Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)); Mapoles, E.R. (Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)); Simpson, J.D.; Gibson, J.B. (General Atomics, Inc ( ))

1994-10-05

230

ICRF (Ion Cyclotron Range of Frequencies) heating and antenna coupling in a high beta tokamak  

SciTech Connect

Maxwell's Equations are solved in two-dimensions for the electromagnetic fields in a toroidal cavity using the cold plasma fluid dielectric tensor in the Ion Cyclotron Range of Frequencies (ICRF). The Vector Wave Equation is transformed to a set of two, coupled second-order partial differential equations with inhomogeneous forcing functions which model a wave launcher. The resulting equations are finite differenced and solved numerically with a complex banded matrix algorithm on a Cray-2 computer using a code described in this report. This code is used to study power coupling characteristics of a wave launcher for low and high beta tokamaks. The low and high beta equilibrium tokamak magnetic fields applied in this model are determined from analytic solutions to the Grad-Shafranov equation. The code shows good correspondence with the results of low field side ICRF heating experiments performed on the Tokamak of Fontenay-Aux-Roses (TFR). Low field side and high field side antenna coupling properties for ICRF heating in the Columbia High Beta Tokamak (HBT) experiment are calculated with this code. Variations of antenna position in the tokamak, ionic concentration and plasma density, and volume-averaged beta have been analyzed for HBT. It is found that the location of the antenna with respect to the plasma has the dominant role in the design of an ICRF heating experiment in HBT. 10 refs., 52 figs., 13 tabs.

Elet, R.S.

1988-01-01

231

ICRF heating and antenna coupling in a high-beta tokamak  

SciTech Connect

Maxwell's Equations are solved in two-dimensions for the electromagnetic fields in a toroidal cavity using the cold plasma fluid dielectric tensor in the Ion Cyclotron Range of Frequencies (ICRF). The Vector Wave Equation is transformed to a set of two, coupled second-order partial differential equations with inhomogeneous forcing functions which model a wave launcher. The resulting equations are finite differenced and solved numerically with a complex banded matrix algorithm on a Cray-2 computer using a code described in this report. This code is used to study power coupling characteristics of a wave launcher for low and high beta tokamaks. The low and high beta equilibrium tokamak magnetic fields applied in this model are determined from analytic solutions to the Grad-Shafranov equation. The code shows good correspondence with the results of low field side ICRF heating experiments performed on the Tokamak of Fontenay-Aux-Roses (TFR). Low field side and high field side antenna coupling properties for ICRF heating in the Columbia High Beta Tokamak (HBT) experiment are calculated with this code. Variations of antenna position in the tokamak, ionic concentration and plasma density, and volume-averaged beta have been analyzed for HBT. It is found that the location of the antenna with respect to the plasma has the dominant role in the design of an ICRF heating experiment in HBT.

Elet, R.S.

1988-01-01

232

Numerical and experimental studies of simulated toroidicity effects in a linear high-beta heliac  

NASA Astrophysics Data System (ADS)

Formation and equilibrium studies of a linear high beta were performed, showing an axial current is induced. Vacuum field numerical studies have shown that when the hardcore center conductor is shifted, the magnetic field structure is similar to a large aspect ratio toroidal heliac. An experiment in a hardcore theta pinch has shown that programming of the hardcore current can significantly reduce the induced axial current. Finite beta effects were incorporated into a code to study the evolution of plasma on a shifted hardcore heliac. These results will be used in an experimental study of simulated toroidicity in a shifted hardcore linear heliac.

Nelson, Brian A.; Spanjers, G.; Ribe, F. L.; Barnes, D. C.; Bishop, R.

1990-03-01

233

Low-Beta Structure for High Energy Part of Project X  

SciTech Connect

Long 11-cell, {beta} = 0.81 L-band structure is considered as an initial stage of the high-energy part of the Project-X in order to accommodate to a standard Type-4 cryomodule. The cavity shape is optimized for maximal energy gain providing the same time field flatness along the structure not worse than for ILC {beta} = 1 cavity, and the same ratio of surface magnetic field to electric field. The results of spectrum analysis for monopole and dipole HOMs is presented as well.

Solyak, N.; Gonin, I.; Yakovlev, V.; /Fermilab; Drozdov, I.; Perunov, N.; /Moscow, MIPT

2009-05-01

234

Free energy landscapes of a highly structured beta-hairpin peptide and its single mutant.  

PubMed

We investigated the free energy landscapes of a highly structured beta-hairpin peptide (MBH12) and a less structured peptide with a single mutation of Tyr6 to Asp6 (MBH10). For the free energy mapping, starting from an extended conformation, the replica exchange molecular dynamic simulations for two beta-hairpins were performed using a modified version of an all-atom force field employing an implicit solvation (param99MOD5/GBSA). With the present simulation approach, we demonstrated that detailed stability changes associated with the sequence modification from MBH12 to MBH10 are quantitatively well predicted at the all-atom level. PMID:19045319

Kim, Eunae; Yang, Changwon; Jang, Soonmin; Pak, Youngshang

2008-10-28

235

Construction of lactose-assimilating and high-ethanol-producing yeasts by protoplast fusion  

SciTech Connect

The availability of a yeast strain which is capable of fermenting lactose and at the same time is tolerant to high concentrations of ethanol would be useful for the production of ethanol from lactose. Kluyveromyces fragilis is capable of fermenting lactose, but it is not as tolerant as Saccharomyces cerevisiae to high concentrations of ethanol. In this study, the authors have used the protoplast fusion technique to construct hybrids between auxotrophic strains of S. cerevisiae having high ethanol tolerance and an auxotrophic strain of lactose-fermenting K. fragilis isolated by ethyl methanesulfonate mutagenesis. The fusants obtained were prototrophic and capable of assimilating lactose and producing ethanol in excess of 13% (vol/vol). The complementation frequency of fusion was about 0.7%. Formation of fusants was confirmed by the increased amount of chromosomal DNA per cell. Fusants contained 8 x 10/sup -9/ to 16 x 10/sup -8/ ..mu..g of DNA per cell as compared with about 4 x 10/sup -8/ ..mu..g of DNA per cell for the parental strains, suggesting that multiple fusions had taken place.

Farahnak, F.; Seki, T.; Ryu, D.D.Y.; Ogrydziak, D.

1986-02-01

236

Microorifice-based high-yield cell fusion on microfluidic chip: electrofusion of selected pairs and fusant viability.  

PubMed

Microorifice-based fusion makes use of electric field constriction to assure high-yield one-to-one fusion of selected cell pairs. The aim of this paper is to verify feasibility of high-yield cell fusion on a microfluidic chip. This paper also examines viability of the fusant created on the chip. We fabricated a microfluidic chip to fuse selected cell pairs and to study postfusion behavior. We used a self-forming meniscus-based fabrication process to create microorifice with a diameter of 2-10 microm on the vertical walls in a microfluidic channel. When 1 MHz was applied to electrodes located on both sides of the microorifice, dielectrophoretic force attracted the cells toward microorifice to form a cell pair. Once the cells get into contact, fusion pulse was applied. Real time imaging of cells during fusion and cytoplasmic dye transfer between cells indicated success of cell fusion. We found that when high frequency voltage for dielectrophoresis was swept from 1 MHz to 10 kHz in 100 micros, cell fusion was initiated. The effective electric field strength was 0.1-0.2 kV/cm. We analyzed viability by imaging fusant going into cell division phase after 48 h of incubation. We conclude that fabricated microfluidic chip is suitable for high-yield one-to-one fusion and creation of viable fusants. This technology should be a useful tool to study fusion phenomena and viability of fusants, as it allows imaging of the cells during and after the fusion. PMID:20142145

Gel, M; Suzuki, S; Kimura, Y; Kurosawa, O; Techaumnat, B; Oana, H; Washizu, M

2009-12-01

237

The relationship of a high level of serum beta-hydroxybutyrate to cause of death.  

PubMed

To examine the state of ketoacidosis in relation to the cause of death, three kinds of ketone bodies (acetoacetate, beta-hydroxybutyrate and acetone) were measured in postmortem serum. Of 100 autopsy cases, 22 had ketone body increasing pathophysiological conditions, overlapped in some cases, namely a poorly-nourished state (10 cases), alcoholic fatty liver damage (10), diabetes (5) and infectious disease (5). Of the 3, 11, 7 and 15 cases in which the beta-hydroxybutyrate concentration was greater than 10,000, 1000-10,000, 500-1000 and 200-500 micromol/l, 3 (100%), 8 (73%), 3 (43%) and 5 (33%), respectively, had one or more pathophysiological conditions that usually produce ketone bodies. Of the 64 cases in which the beta-hydroxybutyrate concentrations were less than 200 micromol/l, only 3 (5%) had some of these conditions. Cases showing high levels of ketone bodies tended to have pathophysiological states that can produce them, although the level of beta-hydroxybutyrate and these states did not show parallel relationships. When autopsy findings fail to explain the cause of death, a diagnosis as death caused by ketoacidosis would be reasonable if the serum beta-hydroxybutyrate level is over 1000 micromol/l and the body has pathophysiological conditions that tend to increase ketone bodies. PMID:15847825

Kanetake, Jun; Kanawaku, Yoshimasa; Mimasaka, Sohtaro; Sakai, Jun; Hashiyada, Masaki; Nata, Masayuki; Funayama, Masato

2005-05-01

238

High precision measurements of {sup 26}Na {beta}{sup -} decay  

SciTech Connect

High-precision measurements of the half-life and {beta}-branching ratios for the {beta}{sup -} decay of {sup 26}Na to {sup 26}Mg have been measured in {beta}-counting and {gamma}-decay experiments, respectively. A 4{pi} proportional counter and fast tape transport system were employed for the half-life measurement, whereas the {gamma} rays emitted by the daughter nucleus {sup 26}Mg were detected with the 8{pi} {gamma}-ray spectrometer, both located at TRIUMF's isotope separator and accelerator radioactive beam facility. The half-life of {sup 26}Na was determined to be T{sub 1/2}=1.07128{+-}0.00013{+-}0.00021 s, where the first error is statistical and the second systematic. The logft values derived from these experiments are compared with theoretical values from a full sd-shell model calculation.

Grinyer, G.F.; Svensson, C.E.; Andreoiu, C.; Finlay, P.; Hyland, B.; Phillips, A.A.; Schumaker, M.A.; Valiente-Dobon, J.J. [Department of Physics, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada); Andreyev, A.N.; Ball, G.C.; Chakrawarthy, R.S.; Hackman, G.; Macdonald, J.A.; Morton, A.C.; Osborne, C.J.; Pearson, C.J.; Sarazin, F.; Scraggs, H.C.; Smith, M.B. [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, V6T 2A3 (Canada); Austin, R.A.E. [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4K1 (Canada)] [and others

2005-04-01

239

Effects of high hydrostatic pressure on the growth and beta-carotene production of Rhodotorula glutinis.  

PubMed

The effects of high hydrostatic pressure (HHP) on the biomass and beta-carotene biosynthesis of Rhodotorula glutinis R68 were studied. After treatment with five repeated cycles at 300 MPa for 15 min, the barotolerant mutant PR68 was obtained. After 72 h of culture, the biomass of mutant PR68 was 21.6 g/l, decreased by 8.5% compared to the parental strain R68, but its beta-carotene production reached 19.4 mg/l, increased by 52.8% compared to the parental strain R68. The result of restriction fragment length polymorphism (RFLP) analysis suggested that mutant strain PR68 was likely to change in nucleic acid level, and thus enhanced beta-carotene production in this strain as a result of gene mutation induced by HHP treatment. PMID:18338316

Wang, Sui-Lou; Chen, De-Jing; Deng, Bai-Wan; Wu, Xiao-Zong

2008-04-01

240

Sensitivity to Error Fields in NSTX High Beta Plasmas  

SciTech Connect

It was found that error field threshold decreases for high ? in NSTX, although the density correlation in conventional threshold scaling implies the threshold would increase since higher ? plasmas in our study have higher plasma density. This greater sensitivity to error field in higher ? plasmas is due to error field amplification by plasmas. When the effect of amplification is included with ideal plasma response calculations, the conventional density correlation can be restored and threshold scaling becomes more consistent with low ? plasmas. However, it was also found that the threshold can be significantly changed depending on plasma rotation. When plasma rotation was reduced by non-resonant magnetic braking, the further increase of sensitivity to error field was observed.

Jong-Kyu Park, Jonathan E. Menard, Stefan P. Gerhardt, Richard J. Buttery, Steve A. Sabbagh, Ronald E. Bell and Benoit P. LeBlanc

2011-11-07

241

Beta-tricalcium phosphate as a bone substitute for dorsal spinal fusion in adolescent idiopathic scoliosis: preliminary results of a prospective clinical study.  

PubMed

The aim of this study is to evaluate the ability of beta-tricalcium phosphate (TCP) in granular form to achieve dorsal spondylodesis in adolescent idiopathic scoliosis (AIS). Twenty-eight patients underwent surgical correction and were followed up for 13+/-8 (range 6-33) months. Posterolateral grafting was performed, using either autograft bone mixed with allograft bone (n=19; "bone group") or autograft bone mixed with 25 g TCP (n=9; "TCP group"). Patients were followed by clinical examination, X-rays and computed tomographic (CT) scans to measure bone mineral density. Fusion involved 12+/-1 (range 10-14) vertebrae. The segments were fused after 6+/-1 months in both groups according to the radiographs. No pseudarthrosis was observed. Bone mineral density was 430+/-111 (range 273-629) mg/cm3 in the TCP group versus 337+/-134 (range 130-669) mg/cm3 in the bone group. Resorption of TCP was complete on the radiographs after 8+/-2 (range 6-10) months. Based upon the results of this small preliminary study, the use of TCP appears to be a valuable alternative to allografts for application in the spine, even when large amounts of bone are needed. PMID:11716016

Muschik, M; Ludwig, R; Halbhübner, S; Bursche, K; Stoll, T

2001-10-01

242

Biomimetic supported lipid bilayers with high cholesterol content formed by ?-helical peptide-induced vesicle fusion  

PubMed Central

In this study, we present a technique to create a complex, high cholesterol-containing supported lipid bilayers (SLBs) using ?-helical (AH) peptide-induced vesicle fusion. Vesicles consisting of POPC : POPE : POPS : SM : Chol (9.35 : 19.25 : 8.25 : 18.15 : 45.00) were used to form a SLB that models the native composition of the human immunodeficiency virus-1 (HIV-1) lipid envelope. In the absence of AH peptides, these biomimetic vesicles fail to form a complete SLB. We verified and characterized AH peptide-induced vesicle fusion by quartz crystal microbalance with dissipation monitoring, neutron reflectivity, and atomic force microscopy. Successful SLB formation entailed a characteristic frequency shift of ?35.4 ± 2.0 Hz and a change in dissipation energy of 1.91 ± 0.52 × 10?6. Neutron reflectivity measurements determined the SLB thickness to be 49.9 +1.9?1.5 Å, and showed the SLB to be 100 +0.0?0.1% complete and void of residual AH peptide after washing. Atomic force microscopy imaging confirmed complete SLB formation and revealed three distinct domains with no visible defects. This vesicle fusion technique gives researchers access to a complex SLB composition with high cholesterol content and thus the ability to better recapitulate the native HIV-1 lipid membrane.

Hardy, Gregory J.; Nayak, Rahul; Alam, S. Munir; Shapter, Joseph G.; Heinrich, Frank; Zauscher, Stefan

2013-01-01

243

Direct drive heavy-ion-beam inertial fusion at high coupling efficiency  

SciTech Connect

Issues with coupling efficiency, beam illumination symmetry, and Rayleigh-Taylor instability are discussed for spherical heavy-ion-beam-driven targets with and without hohlraums. Efficient coupling of heavy-ion beams to compress direct-drive inertial fusion targets without hohlraums is found to require ion range increasing several-fold during the drive pulse. One-dimensional implosion calculations using the LASNEX inertial confinement fusion target physics code shows the ion range increasing fourfold during the drive pulse to keep ion energy deposition following closely behind the imploding ablation front, resulting in high coupling efficiencies (shell kinetic energy/incident beam energy of 16% to 18%). Ways to increase beam ion range while mitigating Rayleigh-Taylor instabilities are discussed for future work.

Logan, B.G.; Perkins, L.J.; Barnard, J.J.

2008-05-16

244

Rational design of highly potent HIV-1 fusion inhibitory proteins: Implication for developing antiviral therapeutics  

SciTech Connect

Recombinant protein containing one heptad-repeat 1 (HR1) segment and one HR2 segment of the HIV-1 gp41 (HR1-HR2) has been shown to fold into thermally stable six-helix bundle, representing the fusogenic core of gp41. In this study, we have used the fusogenic core as a scaffold to design HIV-1 fusion inhibitory proteins by linking another HR1 to the C terminus of HR1-HR2 (HR121) or additional HR2 to the N terminus of HR1-HR2 (HR212). Both recombinant proteins could be abundantly and solubly expressed and easily purified, exhibiting high stability and potent inhibitory activity on HIV-1 fusion with IC{sub 50} values of 16.2 {+-} 2.8 and 2.8 {+-} 0.63 nM, respectively. These suggest that these rationally designed proteins can be further developed as novel anti-HIV-1 therapeutics.

Ni Ling [Department of Molecular Virology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080 (China); Graduate School of the Chinese Academy of Sciences (China); Gao, George F. [Department of Molecular Virology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080 (China)]. E-mail: ggao66@yahoo.com; Tien Po [Department of Molecular Virology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080 (China)]. E-mail: tienpo@sun.im.ac.cn

2005-07-08

245

Direct drive heavy-ion-beam inertial fusion at high coupling efficiency  

NASA Astrophysics Data System (ADS)

Issues with coupling efficiency, beam illumination symmetry, and Rayleigh-Taylor instability are discussed for spherical heavy-ion-beam-driven targets with and without hohlraums. Efficient coupling of heavy-ion beams to compress direct-drive inertial fusion targets without hohlraums is found to require ion range increasing several-fold during the drive pulse. One-dimensional implosion calculations using the LASNEX inertial confinement fusion target physics code shows the ion range increasing fourfold during the drive pulse to keep ion energy deposition following closely behind the imploding ablation front, resulting in high coupling efficiencies (shell kinetic energy/incident beam energy of 16% to 18%). Ways to increase beam ion range while mitigating Rayleigh-Taylor instabilities are discussed for future work.

Logan, B. G.; Perkins, L. J.; Barnard, J. J.

2008-07-01

246

Specific expression of GFP{sub uv}-{beta}1,3-N-acetylglucosaminyltransferase 2 fusion protein in fat body of Bombyx mori silkworm larvae using signal peptide  

SciTech Connect

Bombyxin (bx) and prophenoloxidase-activating enzyme (ppae) signal peptides from Bombyx mori, their modified signal peptides, and synthetic signal peptides were investigated for the secretion of GFP{sub uv}-{beta}1,3-N-acetylglucosaminyltransferase 2 (GGT2) fusion protein in B. mori Bm5 cells and silkworm larvae using cysteine protease deficient B. mori multiple nucleopolyhedrovirus (BmMNPV-CP{sup -} ) and its bacmid. The secretion efficiencies of all signal peptides were 15-30% in Bm5 cells and 24-30% in silkworm larvae, while that of the +16 signal peptide was 0% in Bm5 cells and 1% in silkworm larvae. The fusion protein that contained the +16 signal peptide was expressed specifically in the endoplasmic reticulum (ER) and in the fractions of cell precipitations. Ninety-four percent of total intracellular {beta}1,3-N-acetylglucosaminyltransferase ({beta}3GnT) activity was detected in cell precipitations following the 600, 8000, and 114,000g centrifugations. In the case of the +38 signal peptide, 60% of total intracellular activity was detected in the supernatant from the 114,000g spin, and only 1% was found in the precipitate. Our results suggest that the +16 signal peptide might be situated in the transmembrane region and not cleaved by signal peptidase in silkworm or B. mori cells. Therefore, the fusion protein connected to the +16 signal peptide stayed in the fat body of silkworm larvae with biological function, and was not secreted extracellularly.

Kato, Tatsuya [Laboratory of Biotechnology, Faculty of Agriculture, Shizuoka University, 836 Ohya Suruga-ku, Shizuoka 422-8529 (Japan); Park, Enoch Y. [Laboratory of Biotechnology, Faculty of Agriculture, Shizuoka University, 836 Ohya Suruga-ku, Shizuoka 422-8529 (Japan) and Laboratory of Biotechnology, Integrated Bioscience Section, Graduate School of Science and Technology, Shizuoka University, 836 Ohya Suruga-ku, Shizuoka 422-8529 (Japan)]. E-mail: yspark@agr.shizuoka.ac.jp

2007-08-03

247

Demountable toroidal fusion core facility for physics optimization and fusion engineering  

SciTech Connect

Following a successful compact ignition tokamak (CIT) experiment, a fusion facility will be required for physics optimization (POF) and fusion engineering research (FERF). The POF will address issues such as high-beta operation, current drive, impurity control, and will test geometric and configurational variations such as the spherical torus or the reversed-field pinch (RFP). The FERF will be designed to accumulate rapidly a large neutron dose in prototypical fusion subsystems exposed to radiation. Both facilities will require low-cost replacement cores and rapid replacement times. The Demountable Toroidal Fusion Core (DTFC) facility is designed to fulfill these requirements. It would be a cost-effective stepping stone between the CIT and a demonstration fusion reactor.

Bogart, S.L.; Wagner, C.E.; Krall, N.A.; Dalessandro, J.A.; Weggel, C.F.; Lund, K.O.; Sedehi, S.

1986-01-01

248

Aqueous environmental crack propagation in high-strength beta titanium alloys  

NASA Astrophysics Data System (ADS)

The aqueous environment-assisted cracking (EAC) behavior of two peak-aged beta-titanium alloys was characterized with a fracture mechanics method. Beta-21S is susceptible to EAC under rising load in neutral 3.5 pct NaCl at 25 °C and -600 mVSCE, as indicated by a reduced threshold for subcritical crack growth ( K TH ), an average crack growth rate of up to 10 ?ms, and intergranular fracture compared to microvoid rupture in air. In contrast, the initiation fracture toughness ( K ICi ) of Ti-15-3 in moist air is lower than that of Beta-21S at similar high ?YS (1300 MPa) but is not degraded by chloride, and cracking is by transgranular microvoid formation. The intergranular EAC susceptibility of Beta-21S correlates with both ?-colonies precipitated at ? grain boundaries and intense slip localization; however, the causal factor is not defined. Data suggest that both features, and EAC, are promoted by prolonged solution treatment at high temperature. In a hydrogen environment embrittlement (HEE) scenario, crack-tip H could be transported by planar slip bands to strongly binding trap sites and stress/strain concentrations at ? colony or ? grain boundaries. The EAC in Beta-21S is eliminated by cathodic polarization (to -1000 mVSCE), as well as by static loading for times that otherwise produce rising-load EAC. These beneficial effects could relate to reduced H production at the occluded crack tip during cathodic polarization and to increased crack-tip passive film stability or reduced dislocation transport during deformation at slow crack-tip strain rates. High-strength ?-titanium alloys are resistant, but not intrinsically immune to chloride EAC, with processing condition possibly governing fracture.

Young, Lisa M.; Young, George A.; Scully, John R.; Gangloff, Richard P.

1995-05-01

249

High Current Density Beamlets from an RF Argon Source for Heavy Ion Fusion Applications  

SciTech Connect

In a new approach to develop high current beams for heavy ion fusion, beam current at about 0.5 ampere per channel can be obtained by merging an array of high current density beamlets of 5 mA each. We have done computer simulations to study the transport of high current density beamlets and the emittance growth due to this merging process. In our RF multicusp source experiment, we have produced a cluster of 61 beamlets using minimum gas flow. The current density from a 0.25 cm diameter aperture reached 100 mA/cm{sup 2}. The normalized emittance of 0.02 {pi}-mm-mrad corresponds to an equivalent ion temperature of 2.4 eV. These results showed that the RF argon plasma source is suitable for producing high current density beamlets that can be merged to form a high current high brightness beam for HIF application.

Kwan, J W; Grote, D P; Westenskow, G A

2003-09-04

250

High current density beamlets from RF Argon source for heavy ion fusion applications  

SciTech Connect

In a new approach to develop high current beams for heavy ion fusion, beam current at about 0.5 ampere per channel can be obtained by merging an array of high current density beamlets of 5 mA each. We have done computer simulations to study the transport of high current density beamlets and the emittance growth due to this merging process. In our RF multicusp source experiment, we have produced a cluster of 61 beamlets using minimum gas flow. The current density from a 0.25 cm diameter aperture reached 100 mA/cm{sup 2}. The normalized emittance of 0.02 {pi}-mm-mrad corresponds to an equivalent ion temperature of 2.4 eV. These results showed that the RF argon plasma source is suitable for producing high current density beamlets that can be merged to form a high current high brightness beam for HIF application.

Kwan, J.W.; Grote, D.P.; Westenskow, G.

2003-08-01

251

Clonal analysis of human tumors with M27 beta, a highly informative polymorphic X chromosomal probe.  

PubMed Central

The clonality of human tumors can be studied by X inactivation/methylation analysis in female patients heterozygous for X-linked DNA polymorphisms. We present a detailed study on clonal tumor analysis with M27 beta, a highly informative probe detecting a polymorphic X chromosomal locus, DXS255. The polymorphism detected at this locus is due to variable numbers of tandem repeats. The rate of constitutional heterozygosity detected by M27 beta was 88%. Normal tissue from gastrointestinal mucosa and thyroid showed random, hence polyclonal, patterns. Nonrandom clonal X inactivation was detected in all 22 malignant neoplasms that had been shown to be clonal by other DNA markers, such as antigen receptor gene rearrangements or clonal loss of heterozygosity at 17p and other loci. 16/48 normal blood leukocyte samples (33%) showed considerably skewed X inactivation patterns. Comparison of blood leukocytes and normal tissue indicated that in a given individual, X inactivation patterns may be tissue specific. M27 beta was used to study the clonal composition of 13 benign thyroid nodules from 12 multinodular goiters with rapid recent growth, traditionally termed "adenomas." Nine of them were clonal, whereas four nodules and tissue from a case of Graves' goiter were not, indicating that some, but not all, such thyroid nodules may represent true clonal neoplasms. The M27 beta probe permits one to study the clonal composition by the X inactivation approach of a wide variety of solid tumors from most female patients. As a control, normal tissue homologous to the tumor type of interest is preferable to DNA from blood leukocytes, since the latter may show nonrandom X inactivation patterns in a fairly high proportion of cases. M27 beta may, therefore, be of limited use for the clonal analysis of neoplasms derived from hematopoietic cells. Images

Fey, M F; Peter, H J; Hinds, H L; Zimmermann, A; Liechti-Gallati, S; Gerber, H; Studer, H; Tobler, A

1992-01-01

252

High-flux source of fusion neutrons for material and component testing  

SciTech Connect

The inner part of a fusion reactor will have to operate at very high neutron loads. In steady-state reactors the minimum fluence before the scheduled replacement of the reactor core should be at least l0-15 Mw.yr/m2. A more frequent replacement of the core is hardly compatible with economic constraints. A most recent summary of the discussions of these issues is presented in Ref. [l]. If and when times come to build a commercial fusion reactor, the availability of information on the behavior of materials and components at such fluences will become mandatory for making a final decision. This makes it necessary an early development and construction of a neutron source for fusion material and component testing. In this paper, we present information on one very attractive concept of such a source: a source based on a so called Gas Dynamic Trap. This neutron source was proposed in the mid 1980s (Ref. [2]; see also a survey [3] with discussion of the early stage of the project). Since then, gradual accumulation of the relevant experimental information on a modest-scale experimental facility GDT at Novosibirsk, together with a continuing design activity, have made initial theoretical considerations much more credible. We believe that such a source can be built within 4 or 5 years. Of course, one should remember that there is a chance for developing steady-state reactors with a liquid (and therefore continuously renewable) first wall [4], which would also serve as a tritium breeder. In this case, the need in the neutron testing will become less pressing. However, it is not clear yet that the concept of the flowing wall will be compatible with all types of steady-state reactors. It seems therefore prudent to be prepared to the need of a quick construction of a neutron source. It should also be mentioned that there exist projects of the accelerator-based neutron sources (e.g., [5]). However, they generally have two major disadvantages: a wrong neutron spectrum, with a considerable excess of high-energy neutrons, and smaller test volume. In addition their development requires considerable investments into non-fusion-related technologies, whereas the work on plasma-type sources would certainly boost technology of fusion energy. Broad discussion of these issues can be found in Refs. [3, 6, 7].

Baldwin, D. E.; Hooper, E. B.; Ryutov, D. D.; Thomassen, K. I.

1999-01-07

253

JET intrinsic rotation studies in plasmas with a high normalized beta and varying toroidal field ripple  

NASA Astrophysics Data System (ADS)

Understanding the origin of rotation in ion cyclotron resonance frequency (ICRF) heated plasmas is important for predictions for burning plasmas sustained by alpha particles, being characterized by a large population of fast ions and no external momentum input. The angular velocity of the plasma column has been measured in JET H-mode plasmas with pure ICRF heating both for the standard low toroidal magnetic ripple configuration, of about ˜0.08% and, for increased ripple values up to 1.5% (Nave et al 2010 Phys. Rev. Lett. 105 105005). These new JET rotation data were compared with the multi-machine scaling of Rice et al (2007 Nucl. Fusion 47 1618) for the Alfvén-Mach number and with the scaling for the velocity change from L-mode into H-mode. The JET data do not fit well any of these scalings that were derived for plasmas that are co-rotating with respect to the plasma current. With the standard low ripple configuration, JET plasmas with large ICRF heating power and normalized beta, ?N ? 1.3, have a very small co-current rotation, with Alfvén-Mach numbers significantly below those given by the rotation scaling of Rice et al (2007 Nucl. Fusion 47 1618). In some cases the plasmas are actually counter-rotating. No significant difference between the H-mode and L-mode rotation is observed. Typically the H-mode velocities near the edge are lower than those in L-modes. With ripple values larger than the standard JET value, between 1% and 1.5%, H-mode plasmas were obtained where both the edge and the core counter-rotated.

Nave, M. F. F.; Eriksson, L.-G.; Giroud, C.; Johnson, T. J.; Kirov, K.; Mayoral, M.-L.; Noterdaeme, J.-M.; Ongena, J.; Saibene, G.; Sartori, R.; Rimini, F.; Tala, T.; de Vries, P.; Zastrow, K.-D.; Contributors, JET-EFDA

2012-07-01

254

PROGRESS TOWARD FULLY NONINDUCTIVE, HIGH BETA DISCHARGES IN DIII-D  

SciTech Connect

OAK-B135 Advanced Tokamak (AT) research in DIII-D focuses on developing a scientific basis for steady-state, high performance operation. For optimal performance, these experiments routinely operate with {beta} above the n = 1 no-wall limit, enabled by active feed-back control. The ideal wall {beta} limit is optimized by modifying the plasma shape, current and pressure profile. Present DIII-D AT experiments operate with f{sub BS} {approx} 50%-60%, with a long-term goal of {approx} 90%. Additional current is provided by neutral beam and electron cyclotron current drive, the latter being localized well away from the magnetic axis ({rho} {approx} 0.4-0.5). Guided by integrated modeling, recent experiments have produced discharges with {beta} {approx} 3%, {beta}{sub N} {approx} 3, f{sub BS} {approx} 55% and noninductive fraction f{sub NI} {approx} 90%. Additional control is anticipated using fast wave current drive to control the central current density.

GREENFIELD,CM; FERRON,JR; MURAKAMI,M; WADE,MR; BUDNY,RV; BURRELL,KH; CASPER,TA; DeBOO,JC; DOYLE,EJ; GAROFALO,AM; JAYAKUMAR,RJ; KESSEL,C; LAO,LL; LOHR,J; LUCE,TC; MAKOWSKI,MA; MENARD,JE; PETRIE,TW; PETTY,CC; PINSKER,RI; PRATER,R; POLITZER,PA; St JOHN,HE; TAYLOR,TS; WEST,WP; DIII-D NATIONAL TEAM

2003-08-01

255

Construction and characterization of a recombinant human beta defensin 2 fusion protein targeting the epidermal growth factor receptor: in vitro study.  

PubMed

The HER2/neu proto-oncogene encodes a 185-kDa trans-membrane glycoprotein kinase with extensive homology to the epidermal growth factor receptor and plays a key role in the transformation and growth of malignant tumors. To date, two antibody drugs targeting HER2/neu have been developed successfully. In order to reduce the cost and the time of clinical treatment, we produced a fusion protein composed of human beta defensin 2 (hBD2) and anti-HER2/neu single-chain variable fragment (scFv 4D5), which is capable of specifically targeting, significantly inhibiting, and promptly killing HER2/neu-positive cancer cells. The recombinant protein was expressed in Escherichia coli using the small ubiquitin-related modifier (SUMO) as the molecular chaperone, and the optimal expression level reached to 40.2 % of the total supernatant protein. After purifying by Ni-NTA affinity chromatography, the fusion protein was cleaved with a SUMO-specific protease to obtain hBD2-4D5, which was further purified by Ni-NTA affinity chromatography. The purity of hBD2-4D5 was higher than 95 %, and the yield was 19?±?2 mg/L in flask fermentation. The cell number count and flow cytometry results showed that hBD2-4D5 exerted cytotoxic and anti-proliferative effects on HER2/neu-positive breast cancer cell line, SKBR-3. The results of scanning electron microscope and transmission electron microscope observation indicated that hBD2-4D5 could induce intracellular ultrastructure changes and cell necrosis by disrupting the cell membrane. Immunofluorescence analysis showed that hBD2-4D5 could bind to SKBR-3 cells and further be internalized into the cytoplasm. Moreover, hBD2-4D5 could also mediate apoptosis of SKBR-3 cells by up-regulating the ratio of Bax to Bcl-2. PMID:22903275

Zhang, Minjing; Qiu, Zhuangwei; Li, Yinyu; Yang, Yan; Zhang, Qihao; Xiang, Qi; Su, Zhijian; Huang, Yadong

2012-08-05

256

A fusion power plant without plasma-material interactions  

Microsoft Academic Search

A steady-state fusion power plant is described which avoids the deleterious plasma-material interactions found in D-T fueled tokamaks. It is based on driven p-¹¹B fusion in a high-beta closed-field device, the field-reversed configuration (FRC), anchored in a gas-dynamic trap (GDT). The plasma outflow on the open magnetic-field lines is cooled by radiation in the GDT, then channeled through a magnetic

1997-01-01

257

Final Report on The Theory of Fusion Plasmas  

SciTech Connect

Report describes theoretical research in the theory of fusion plasmas funded under grant DE-FG02-04ER54737. This includes work on: explosive instabilities, plasma turbulence, Alfven wave cascades, high beta (pressure) tokamaks and magnetic reconnection. These studies have lead to abetter understanding of fusion plasmas and in particular the future behavior of ITER. More than ten young researchers were involved in this research -- some were funded under the grant.

Steven C. Cowley

2008-06-17

258

Altered lipid content inhibits autophagic vesicular fusion.  

PubMed

The autophagic/lysosomal system includes a variety of vesicular compartments that undergo dynamic fusion events. However, the characteristics and factors modulating these interactions remain, for the most part, unknown. To gain insights on the properties that govern lysosomal fusion events, we have established an in vitro fusion assay using different lysosomal/autophagic compartments isolated from mouse liver. We have found that autophagosome/lysosome fusion is a temperature-dependent process (fusion increment of 0.2+/-0.01%/degrees C), which requires ATP (1-3 mM), GTP (1-2 mM), Ca(2+) (0.2-2 mM), and an acidic lysosomal pH (pH 5.2). Furthermore, changes in membrane lipid composition, induced either in vitro, by treatment with 25 mM methyl-beta-cyclodextrin, or in vivo, by subjecting animals to a high-fat-diet challenge (60% kcal in fat) reduce autophagosome/lysosome fusion up to 70% of that observed in untreated fractions or from animals under a normal regular diet. These findings reveal a novel role for lipids in autophagic fusion and provide a mechanism for the reduced macroautophagic rates observed during exposure to a chronic lipid challenge. Changes in the intracellular lipid content (i.e., metabolic disorders) may thus have pronounced effects on the fusion step of macroautophagy and affect the overall activity of this intracellular proteolytic pathway. PMID:20375270

Koga, Hiroshi; Kaushik, Susmita; Cuervo, Ana Maria

2010-04-07

259

Fluctuations in high beta(sub p) plasmas in DIII-D  

NASA Astrophysics Data System (ADS)

In our investigation of improved confinement in high poloidal beta (beta(sub p) = 2 to 4) advanced tokamak experiments, coincident with q(sub 0) rising above 2, we observe the internal MHD activity to evolve from an m/n = 2/1 to a 3/1 structure consistent with the GATO code stability analysis. The plasma eventually evolves to a quiescent state at which time the stored energy increases, mostly as a result of improved particle confinement. The measured plasma pressure profiles during this time are also calculated to be stable to high-n ballooning modes consistent with operation of the core in the second stable regime. The sustained improvement in confinement is ultimately limited by our ability to control the toroidal current profile of which the bootstrap current contributes a large fraction (up to 80%).

Casper, T. A.; Chu, M. S.; Gohil, C. P.

1994-06-01

260

Fluctuations in high Beta(sub p) plasmas in D3-D  

NASA Astrophysics Data System (ADS)

In our investigation of improved confinement in high poloidal beta (beta(sub p)= 2 to 4) advanced tokamak experiments, we observe that the internal MHD activity evolves from an m/n = 2/1 to a 3/1 structure coincident with q(sub o) rising above 2, and consistent with the GATO code stability analysis. The plasma eventually evolves to a quiescent state at which time the stored energy increases, mostly as a result of improved particle confinement. The bootstrap fraction rises to 80%. The measured plasma pressure profiles during this time are calculated to be stable to high-n ballooning modes consistent with operation of the core in the second stable regime. The sustained improvement in confinement is ultimately limited by our ability to control the toroidal current profile.

Casper, T. A.; Chu, M. S.; Gohil, P.; Heidbrink, W. W.; Hyatt, A. W.; James, R. A.; Jong, R. A.; Lao, L. L.; Makowski, M. A.; Meyer, W. H.

1994-07-01

261

High Temperature Fusion Reactor Cooling Using Brayton Cycle Based Partial Energy Conversion  

NASA Astrophysics Data System (ADS)

For some future space power systems using high temperature nuclear heat sources most of the output energy will be used in other than electrical form, and only a fraction of the total thermal energy generated will need to be converted to electrical work. The paper describes the conceptual design of such a ``partial energy conversion'' system, consisting of a high temperature fusion reactor operating in series with a high temperature radiator and in parallel with dual closed cycle gas turbine (CCGT) power systems, also referred to as closed Brayton cycle (CBC) systems, which are supplied with a fraction of the reactor thermal energy for conversion to electric power. Most of the fusion reactor's output is in the form of charged plasma which is expanded through a magnetic nozzle of the interplanetary propulsion system. Reactor heat energy is ducted to the high temperature series radiator utilizing the electric power generated to drive a helium gas circulation fan. In addition to discussing the thermodynamic aspects of the system design the authors include a brief overview of the gas turbine and fan rotor-dynamics and proposed bearing support technology along with performance characteristics of the three phase AC electric power generator and fan drive motor.

Juhasz, Albert J.; Sawicki, Jerzy T.

2004-02-01

262

Identification of a novel member of the TGF-beta superfamily highly expressed in human placenta  

Microsoft Academic Search

While conducting a gene discovery effort targeted to transcripts of the prevalent and intermediate frequency classes in placenta throughout gestation, we identified a novel member of the TGF-? superfamily that is expressed at high levels in human placenta. Hence, we named this factor `Placental Transforming Growth Factor Beta' (PTGFB). The full-length sequence of the 1.2-kb PTGFB mRNA has the potential

Lee N Lawton; Maria de Fatima Bonaldo; Pierre C Jelenc; Ling Qiu; Susan A Baumes; Rudy A Marcelino; Gracielle M de Jesus; Sandra Wellington; James A Knowles; Dorothy Warburton; Stephen Brown; Marcelo Bento Soares

1997-01-01

263

High beta, Long Pulse, Bootstrap Sustained Scenarios on the National Spherical Torus Experiment (NSTX)  

SciTech Connect

Long-pulse, high-beta scenarios have been established on the National Spherical Torus Experiment (NSTX). Beta(sub)t(always equal to 2{mu}(sub)0{center_dot}

/B{sup 2}(sub)t0) {approx} 35% has been achieved during transient discharges. The machine improvements that lead to these results, including error field reduction and high-temperature bakeout of plasma-facing components are described. The highest Beta(sub)t plasmas have high triangularity (delta = 0.8) and elongation (k = 2.0) at low-aspect ratio A always equal to R/a = 1.4. The strong shaping permits large values of normalized current, I(sub)N(always equal to I(sub)p /(aB(sub)t0)) approximately equal to 6 while maintaining moderate values of q(sub)95 = 4. Long-pulse discharges up to 1 sec in duration have been achieved with substantial bootstrap current. The total noninductive current drive can be as high as 60%, comprised of 50% bootstrap current and {approx}10% neutral-beam current drive. The confinement enhancement factor H89P is in excess of 2.7. Beta(sub)N * H(sub)89P approximately or greater than 15 has been maintained for 8 * tau(sub)E {approx} 1.6 * tau(sub)CR, where tau(sub)CR is the relaxation time of the first radial moment of the toroidal current density. The ion temperature for these plasmas is significantly higher than that predicted by neoclassical theory.

D.A. Gates, for the NSTX National Research Team

2003-02-26

264

Cloning of the beta Cell High-Affinity Sulfonylurea Receptor: A Regulator of Insulin Secretion  

Microsoft Academic Search

Sulfonylureas are a class of drugs widely used to promote insulin secretion in the treatment of non-insulin-dependent diabetes mellitus. These drugs interact with the sulfonylurea receptor of pancreatic beta cells and inhibit the conductance of adenosine triphosphate (ATP)-dependent potassium (KATP) channels. Cloning of complementary DNAs for the high-affinity sulfonylurea receptor indicates that it is a member of the ATP-binding cassette

Lydia Aguilar-Bryan; Colin G. Nichols; Sergio W. Wechsler; John P. Clement IV; A. E. Boyd III; Gabriela Gonzalez; Haydee Herrera-Sosa; Kimberly Nguy; Joseph Bryan; Daniel A. Nelson

1995-01-01

265

PRODUCTION AND TESTING RESULTS OF SUPERCONDUCTING CAVITIES FOR ISAC-II HIGH BETA SECTION  

Microsoft Academic Search

The ISAC-II heavy ion linear accelerator has been in operation at TRIUMF since 2006. The high beta section of the accelerator, consisting of twenty cavities with optimum ?0=0.11, is currently under production and is scheduled for completion in 2009. The cavities are superconducting bulk Niobium two-gap quarter-wave resonators with a frequency of 141 MHz, providing, as a design goal, a

V. Zvyagintsev; R. E. Laxdal; T. Bohdanowicz; R. Dawson; K. Fong; A. Grasselino; P. Harmer; D. Kishi; M. Marchetto; A. K. Mitra; T. Ries; I. Sekachev; B. Waraich; D. Yosifov; Q. Zheng; R. Edinger

266

MICRO-HETEROGENEITY AND MICRO-RHEOLOGICAL PROPERTIES OF HIGH-VISCOSITY OAT BETA-GLUCAN SOLUTIONS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Soluble fiber beta-glucan is one of the key dietary materials in healthy food products known for reducing serum cholesterol levels. The micro-structural heterogeneity and micro-rheology of high-viscosity oat beta-glucan solutions were investigated by monitoring the thermally driven displacements of...

267

Formation of high-beta plasma and stable confinement of toroidal electron plasma in Ring Trap 1  

Microsoft Academic Search

Formation of high-beta electron cyclotron resonance heating plasma and stable confinement of pure electron plasma have been realized in the Ring Trap 1 device, a magnetospheric configuration generated by a levitated dipole field magnet. The effects of coil levitation resulted in drastic improvements of the confinement properties, and the maximum local beta value has exceeded 70%. Hot electrons are major

H. Saitoh; Z. Yoshida; J. Morikawa; M. Furukawa; Y. Yano; Y. Kawai; M. Kobayashi; G. Vogel; H. Mikami

2011-01-01

268

Beta-endorphin immunoreactivity during high-intensity exercise with and without opiate blockade.  

PubMed

Nine highly fit men [mean (SE) maximum oxygen uptake, VO2max: 63.9 (1.7) ml x kg(-1) x min(-1); age 27.6 (1.6) years] were studied during two treadmill exercise trials to determine plasma beta-endorphin immunoreactivity during intense exercise (80% VO2max). A double-blind experimental design was used, and subjects performed the two exercise trials in counterbalanced order. Exercise trials were 30 min in duration and were conducted 7 days apart. One exercise trial was undertaken following administration of naloxone (1.2 3 cm3) and the other after receiving a placebo (0.9% NaCl saline; 3 cm3). Prior to each experimental trial, a flexible catheter was placed into an antecubital vein and baseline blood samples were collected. Thereafter, each subject received either a naloxone or placebo bolus injection. Blood samples were also collected after 10, 20 and 30 min of continuous exercise. beta-Endorphin was higher (P < 0.05) during exercise when compared to pre-exercise in both trials. However, no statistically significant difference was found (P> 0.05) between exercise time points within either experimental trial. beta-endorphin immunoreactivity was greater (P < 0.05) in the naloxone than in the placebo trial during each exercise sampling time point [10 min: 63.7 (3.9) pg x ml(-1) vs 78.7 (3.8) pg x ml(-1); 20 min: 68.7 (4.1) pg x ml(-1) vs (4.3) pg x ml(-1); 30 min: 71.0 (4.3) pg x ml(-1) vs 82.5(3.2) pg x ml(-1)]. These data suggest that intense exer induces significant increases in beta-endorphin that are maintained over time during steady-rate exercise. Exercise and naloxone had an interactive effect on beta-endorphin release that warrants further investigation. PMID:11820329

Angelopoulos, T J

2001-11-01

269

IEFIT - An Interactive Approach to High Temperature Fusion Plasma Magnetic Equilibrium Fitting  

SciTech Connect

An interactive IDL based wrapper, IEFIT, has been created for the magnetic equilibrium reconstruction code EFIT written in FORTRAN. It allows high temperature fusion physicists to rapidly optimize a plasma equilibrium reconstruction by eliminating the unnecessarily repeated initialization in the conventional approach along with the immediate display of the fitting results of each input variation. It uses a new IDL based graphics package, GaPlotObj, developed in cooperation with Fanning Software Consulting, that provides a unified interface with great flexibility in presenting and analyzing scientific data. The overall interactivity reduces the process to minutes from the usual hours.

Peng, Q.; Schachter, J.; Schissel, D.P.; Lao, L.L.

1999-06-01

270

Two-photon fusion in high-energy electron-nucleus scattering  

SciTech Connect

Experimental studies of meson production through two-photon fusion in inelastic electron-nucleus scattering are now under way. A high-energy photon radiated by the incident electron is fused with a soft photon radiated by the nucleus to create the meson. The process takes place in the small-angle Coulomb region of nuclear scattering. We expound the theory for this production process as well as its interference with coherent-radiative-meson production. In particular, we investigate the distortion of the electron wave function due to multiple-Coulomb scattering.

Faeldt, Goeran [Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20 Uppsala (Sweden)

2011-04-15

271

Two-photon fusion in high-energy electron-nucleus scattering  

NASA Astrophysics Data System (ADS)

Experimental studies of meson production through two-photon fusion in inelastic electron-nucleus scattering are now under way. A high-energy photon radiated by the incident electron is fused with a soft photon radiated by the nucleus to create the meson. The process takes place in the small-angle Coulomb region of nuclear scattering. We expound the theory for this production process as well as its interference with coherent-radiative-meson production. In particular, we investigate the distortion of the electron wave function due to multiple-Coulomb scattering.

Fäldt, Göran

2011-04-01

272

High-precision branching ratio measurement for the superallowed {beta}{sup +} emitter {sup 62}Ga  

SciTech Connect

A high-precision branching ratio measurement for the superallowed {beta}{sup +} decay of {sup 62}Ga was performed at the Isotope Separator and Accelerator (ISAC) radioactive ion beam facility. The 8{pi} spectrometer, an array of 20 high-purity germanium detectors, was employed to detect the {gamma} rays emitted following Gamow-Teller and nonanalog Fermi {beta}{sup +} decays of {sup 62}Ga, and the SCEPTAR plastic scintillator array was used to detect the emitted {beta} particles. Thirty {gamma} rays were identified following {sup 62}Ga decay, establishing the superallowed branching ratio to be 99.858(8)%. Combined with the world-average half-life and a recent high-precision Q-value measurement for {sup 62}Ga, this branching ratio yields an ft value of 3074.3{+-}1.1 s, making {sup 62}Ga among the most precisely determined superallowed ft values. Comparison between the superallowed ft value determined in this work and the world-average corrected Ft value allows the large nuclear-structure-dependent correction for {sup 62}Ga decay to be experimentally determined from the CVC hypothesis to better than 7% of its own value, the most precise experimental determination for any superallowed emitter. These results provide a benchmark for the refinement of the theoretical description of isospin-symmetry breaking in A{>=}62 superallowed decays.

Finlay, P.; Svensson, C. E.; Bandyopadhyay, D.; Grinyer, G. F.; Hyland, B.; Leach, K. G.; Phillips, A. A.; Schumaker, M. A.; Wong, J. [Department of Physics, University of Guelph, Guelph, Ontario N1G 2W1 (Canada); Ball, G. C.; Chakrawarthy, R. S.; Hackman, G.; Kanungo, R.; Morton, A. C.; Pearson, C. J.; Savajols, H. [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3 (Canada); Leslie, J. R.; Towner, I. S. [Department of Physics, Queen's University, Kingston, Ontario K7L 3N6 (Canada); Austin, R. A. E.; Chaffey, A. [Department of Astronomy and Physics, Saint Mary's University, Halifax, Nova Scotia B3H 3C3 (Canada)] (and others)

2008-08-15

273

What role (if any) does the highly conserved CSB-PGBD3 fusion protein play in Cockayne syndrome?  

PubMed

The PGBD3 piggyBac transposon inserted into CSB intron 5 early in the primate lineage. As a result of alternative splicing, the human CSB gene now encodes three proteins: CSB, a CSB-PGBD3 fusion protein that joins the N-terminal CSB domain to the C-terminal PGBD3 transposase domain, and PGBD3 transposase. The fusion protein is as highly conserved as CSB, suggesting that it is advantageous in health; however, expression of the fusion protein in CSB-null cells induces a constitutive interferon (IFN) response. The fusion protein binds in vivo to PGBD3-related MER85 elements, but is also tethered to c-Jun, TEAD1, and CTCF motifs by interactions with the cognate transcription factors. The fusion protein regulates nearby genes from the c-Jun (and to a lesser extent TEAD1 and CTCF) motifs, but not from MER85 elements. We speculate that the fusion protein interferes with CSB-dependent chromatin remodeling, generating double-stranded RNA (dsRNA) that induces an IFN response through endosomal TLR or cytoplasmic RIG-I and/or MDA5 RNA sensors. We suggest that the fusion protein was fixed in primates because an elevated IFN response may help to fight viral infection. We also speculate that an inappropriate IFN response may contribute to the clinical presentation of CS. PMID:23369858

Weiner, Alan M; Gray, Lucas T

2013-01-28

274

An integrated system for automatic road mapping from high-resolution multi-spectral satellite imagery by information fusion  

Microsoft Academic Search

Here we present an integrated system for automatic mapping of urban and suburban roads from high-resolution satellite imagery. Road extraction strategies can be enriched and improved by multi-source data fusion. Fusion can occur by combining road extraction results from different image sources, or by applying multiple detectors to a single source image and then fusing the multi-detector road extraction results.

Xiaoying Jin; Curt H. Davis

2005-01-01

275

Dynamic Formation of a Hot Field Reversed Configuration with Improved Confinement by Supersonic Merging of Two Colliding High-{beta} Compact Toroids  

SciTech Connect

A hot stable field-reversed configuration (FRC) has been produced in the C-2 experiment by colliding and merging two high-{beta} plasmoids preformed by the dynamic version of field-reversed {theta}-pinch technology. The merging process exhibits the highest poloidal flux amplification obtained in a magnetic confinement system (over tenfold increase). Most of the kinetic energy is converted into thermal energy with total temperature (T{sub i}+T{sub e}) exceeding 0.5 keV. The final FRC state exhibits a record FRC lifetime with flux confinement approaching classical values. These findings should have significant implications for fusion research and the physics of magnetic reconnection.

Binderbauer, M. W.; Guo, H. Y.; Tuszewski, M.; Putvinski, S.; Sevier, L.; Barnes, D.; Rostoker, N.; Anderson, M. G.; Andow, R.; Bonelli, L.; Brown, R.; Bui, D. Q.; Bystritskii, V.; Clary, R.; Cheung, A. H.; Conroy, K. D.; Deng, B. H.; Dettrick, S. A.; Douglass, J. D.; Feng, P. [Tri Alpha Energy, Inc., Post Office Box 7010, Rancho Santa Margarita, California 92688 (United States)

2010-07-23

276

KrF laser path to high gain ICF (inertial confinement fusion) laboratory microfusion facility  

NASA Astrophysics Data System (ADS)

The krypton-fluoride laser has many desirable features for inertial confinement fusion. Because it is a gas laser capable of operation with high efficiency, it is the only known laser candidate capable of meeting the driver requirements for inertial fusion energy (IFE) production. Los Alamos National Laboratory has defined a program plan to develop KrF lasers for IFE production. This plan develops the KrF laser and demonstrates the target performance in single-pulse facilities. A 100-kJ Laser Target Test Facility (LTTF) is proposed as the next step, to be followed by a 3 to 10-MJ Laboratory Microfusion Facility (LMF). The LTTF will resolve many target physics issues and accurately define the driver energy required for the LMF. It is also proposed that the technology development for IFE, such as the high-efficiency, high-reliability, repetitively pulsed driver, the reactor, mass production of targets, and the mechanism of injecting targets be developed in parallel with the single-pulse facilities.

Harris, David B.; Sullivan, J. Al; Figueiro, Joseph F.; Cartwright, David C.; McDonald, Thomas E.; Hauer, Allan A.; Coggeshall, Stephen V.; Younger, Stephen M.

1990-09-01

277

A Petawatt-Laser-Driven, High-Flux Neutron Source for Fusion Micro-Materials Irradiation  

NASA Astrophysics Data System (ADS)

We are examining the application of petawatt lasers to create beam-target fusion neutrons via ponderomotive-driven, electrostatic coupling. This offers a low cost, high-flux, “micro” 14MeV neutron source for testing tensile strengths of small ( ~100?m) fibers of C, Al_2O_3, SiC, etc., to ~100dpa. Such fibers can form porous fabric tubes for flowing coolant/breeders ( Flibe, LiPb, LiO_2-sand) in a various applications (direct-drive ICF, spheromaks, etc.). Under very short, intense laser heating of a thin tritium-frost layer, ejection of hot (multi-MeV) tail electrons driven by the ponderomotive pressure of the laser field competes with thermal electron heat conduction. Hot ions are ejected from the tritium layer by the resulting potential and move into a deuterium-ice substrate, pre-heated by the hot electrons. Beam-target fusion neutrons are produced at high efficiency (i.e., Q ~0.01-0.1 relative to Q ~0.001 for conventional solid, cold targets), while small target dimensions yield high neutron fluxes. Formal treatment of laser-induced electrostatic potentials is required to accurately model electron/ion transport.

Logan, B. G.; Perkins, L. J.; Ditmire, T.; Rosen, M. D.; Perry, M. D.; Key, M. H.; Diaz de La Rubia, T.; Wolfer, W. G.

1998-11-01

278

Beta-galactosidase activity in single differentiating bacterial cells.  

PubMed Central

Myxococcus xanthus strains containing transcriptional fusions to lacZ were analyzed and fractionated by differences in their levels of beta-galactosidase expression. The fluorogenic substrate for beta-galactosidase, fluorescein di-beta-galactopyranoside, was introduced into M. xanthus cells during a rapid decrease in osmolarity of the medium followed by a return to isoosmolarity. Fluorescein, the product of hydrolysis, was retained within the cells and their viability was preserved. Fluorescence increased linearly with time and was proportional to beta-galactosidase activity. beta-Galactosidase expression in most fusion strains, though beginning at different phases of growth or development, was distributed unimodally amongst cells. However, fusion strain Tn5 lac omega 4473 was shown to be heterogeneous at 9 hr of development. It was possible to separate physically cells that expressed beta-galactosidase at a high level from other, still viable, cells with no expression. The approach described here could be adapted to study differentiation in plants and animals as well, where transcriptional fusions and fluorogenic substrates for enzyme probes of gene expression also can be used. Images Fig. 5

Russo-Marie, F; Roederer, M; Sager, B; Herzenberg, L A; Kaiser, D

1993-01-01

279

KSTAR Equilibrium Operating Space and Projected Stabilization at High Normalized Beta  

SciTech Connect

Along with an expanded evaluation of the equilibrium operating space of the Korea Superconducting Tokamak Advanced Research, KSTAR, experimental equilibria of the most recent plasma discharges were reconstructed using the EFIT code. In near-circular plasmas created in 2009, equilibria reached a stored energy of 54 kJ with a maximum plasma current of 0.34 MA. Highly shaped plasmas with near double-null configuration in 2010 achieved H-mode with clear edge localized mode (ELM) activity, and transiently reached a stored energy of up to 257 kJ, elongation of 1.96 and normalized beta of 1.3. The plasma current reached 0.7 MA. Projecting active and passive stabilization of global MHD instabilities for operation above the ideal no-wall beta limit using the designed control hardware was also considered. Kinetic modification of the ideal MHD n = 1 stability criterion was computed by the MISK code on KSTAR theoretical equilibria with a plasma current of 2 MA, internal inductance of 0.7 and normalized beta of 4.0 with simple density, temperature and rotation profiles. The steep edge pressure gradient of this equilibrium resulted in the need for significant plasma toroidal rotation to allow thermal particle kinetic resonances to stabilize the resistive wall mode (RWM). The impact of various materials and electrical connections of the passive stabilizing plates on RWM growth rates was analysed, and copper plates reduced the RWM passive growth rate by a factor of 15 compared with stainless steel plates at a normalized beta of 4.4. Computations of active RWM control using the VALEN code showed that the n = 1 mode can be stabilized at normalized beta near the ideal wall limit via control fields produced by the midplane in-vessel control coils (IVCCs) with as low as 0.83kW control power using ideal control system assumptions. The ELM mitigation potential of the IVCC, examined by evaluating the vacuum island overlap created by resonant magnetic perturbations, was analysed using the TRIP3D code. Using a combination of all IVCCs with dominant n = 2 field and upper/lower coils in an even parity configuration, a Chirikov parameter near unity at normalized poloidal flux 0.83, an empirically determined condition for ELM mitigation in DIII-D, was generated in theoretical high-beta equilibria. Chirikov profile optimization was addressed in terms of coil parity and safety factor profile.

Park, Y. S. [Columbia University; Sabbagh, S. A. [Columbia University; Berkery, J.W. [Columbia University; Bialek, J. [Columbia University; Jeon, Y. M. [National Fusion Research Institute, Daejon, South Korea; Hahn, S. H. [National Fusion Research Institute, Daejon, South Korea; Eidietis, N. W. [General Atomics, San Diego; Evans, T. E. [General Atomics, San Diego; Yoon, S. W. [National Fusion Research Institute, Daejon, South Korea; Ahn, Joonwook [ORNL; Kim, J. [National Fusion Research Institute, Daejon, South Korea; Yang, H. L. [National Fusion Research Institute, Daejon, South Korea; You, K. I. [National Fusion Research Institute, Daejon, South Korea; Soukhanovskii, V. A. [Lawrence Livermore National Laboratory (LLNL); Bae, Y. S. [National Fusion Research Institute, Daejon, South Korea; Chung, J. I. [National Fusion Research Institute, Daejon, South Korea; Kwon, M. [National Fusion Research Institute, Daejon, South Korea; Oh, Y. K. [National Fusion Research Institute, Daejon, South Korea; Kim, W. C. [National Fusion Research Institute, Daejon, South Korea; Kim, J. Y. [National Fusion Research Institute, Daejon, South Korea; Lee, S. G. [National Fusion Research Institute, Daejon, South Korea; Park, H. [Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea; Reimerdes, H. [Columbia University; Leuer, J. A. [General Atomics, San Diego; Walker, M. L. [General Atomics, San Diego

2011-01-01

280

Characterization of high-affinity binding between gangliosides and amyloid beta-protein.  

PubMed

The binding specificities of amyloid beta-protein (A beta) such as A beta 1-40, A beta 1-42, A beta 40-1, A beta 1-38, A beta 25-35, and amyloid beta precursor protein (beta-APP) analogues for different glycosphingolipids were determined by surface plasmon resonance (SPR) using a liposome capture method. A beta 1-42, A beta 1-40, A beta 40-1, and A beta 1-38, but not A beta 25-35, bound to GM1 ganglioside in the following rank order: A beta 1-42 > A beta 40-1 > A beta 1-40 > A beta 1-38. The beta-APP analogues bound to GM1 ganglioside with a relatively lower affinity. Aged derivatives of A beta were found to have higher affinity to GM1 ganglioside than fresh or soluble derivatives. A beta 1-40 bound to a number of gangliosides with the following order of binding strength: GQ1b alpha > GT1a alpha > GQ1b > GT1b > GD3 > GD1a = GD1b > LM1 > GM1 > GM2 = GM3 > GM4. Neutral glycosphingolipids had a lower affinity for A beta 1-40 than gangliosides with the following order of binding strength: Gb4 > asialo-GM1 (GA1) > Gb3 > asialo-GM2 (GA2) = LacCer. The results seem to indicate that an alpha2,3NeuAc residue on the neutral oligosaccharide core is required for binding. In addition, the alpha2-6NeuAc residue linked to GalNAc contributes significantly to binding affinity for A beta. PMID:11368158

Ariga, T; Kobayashi, K; Hasegawa, A; Kiso, M; Ishida, H; Miyatake, T

2001-04-15

281

High beta results in ISX-B with intense neutral beam injection  

SciTech Connect

Experiments on the ISX-B device show a deterioration in confinement at high beam power. In particular the electron energy confinement time falls catastrophically with increasing beam power. The maximum volume averaged beta values achieved are <2.5%; this is much less than would be predicted by extrapolating the low power data. Elongation has not been observed to have any significant effect on the maximum attainable beta, perhaps due to the limited range of both internal and external elongation. The electron energy confinement time does not follow Alcator scaling at high injection powers. There are two likely candidates for the loss of confinement. The phenomena may be ..beta../sub p/ specific and caused by the gradual onset of resistive MHD pressure driven modes producing deteriorating confinement through fluctuations in the poloidal magnetic field. Alternatively the phenomena may be specific to the method of heating, neutral injection, being caused, for example, by plasma rotation, where the rotation speed approaches the ion thermal velocity. Experiments are in progress to investigate both of these possibilities.

Edmonds, P.H.; Bates, S.C.; Bell, J.D.

1982-01-01

282

RESISTIVE WALL STABILIZATION OF HIGH BETA PLASMAS IN DIII-D  

SciTech Connect

OAK A271 RESISTIVE WALL STABILIZATION OF HIGH BETA PLASMAS IN DIII-D. Recent DIII-D experiments show that ideal kink modes can be stabilized at high beta by a resistive wall, with sufficient plasma rotation. However, the resonant response by a marginally stable resistive wall mode to static magnetic field asymmetries can lead to strong damping of the rotation. Careful reduction of such asymmetries has allowed plasmas with beta well above the ideal MHD no-wall limit, and approaching the ideal-wall limit, to be sustained for durations exceeding one second. Feedback control can improve plasma stability by direct stabilization of the resistive wall mode or by reducing magnetic field asymmetry. Assisted by plasma rotation, direct feedback control of resistive wall modes with growth rates more than 5 times faster than the characteristic wall time has been observed. These results open a new regime of tokamak operation above the free-boundary stability limit, accessible by a combination of plasma rotation and feedback control.

STRAIT,EJ; BIALEK,J; BOGATU,N; CHANCE,M; CHU,MS; EDGELL,D; GAROFALO,AM; JACKSON,GL; JENSEN,TH; JOHNSON,LC; KIM,JS; LAHAYE,RJ; NAVRATIL,G; OKABAYASHI,M; REIMERDES,H; SCOVILLE,JT; TURNBULL,AD; WALKER,ML

2002-09-01

283

3-D simulations of limiter stabilization of high-beta external kink-tearing modes  

SciTech Connect

The effects of finite-size poloidal limiters, toroidal limiters, and general mushroom limiters are examined for high-beta finite-resistivity tokamak plamas in free boundary. Even for a linear stability analysis, a 3-D simulation is necessary, in which many poloidal and toroidal modes are coupled because of the limiter constraint and finite-beta. When the plasma pressure and resistivity are small, a poloidal limiter is effective in reducing the growth rate with a small limiter-size, while a toroidal limiter requires a large size for a comparable effect. As the plasma pressure or resistivity increases, a toroidal limiter becomes more effective in reducing the growth rate than a poloidal limiter of the same size. A small optimized mushroom limiter might have a stabilizing effect similar to a conducting shell.

Lee, J.K.; Ohyabu, N.

1984-03-01

284

Design and material issues for high performance SiC f\\/SiC-based fusion power cores  

Microsoft Academic Search

The SiCf\\/SiC composite is a promising structural material candidate for fusion power cores and has been considered internationally in several power plant studies. It offers safety advantages arising from its low induced radioactivity and afterheat, and the possibility of high performance through high temperature operation. However, its behavior and performance at high temperatures and under irradiation are still not well

A. R. Raffray; R. Jones; G. Aiello; M. Billone; L. Giancarli; H. Golfier; A. Hasegawa; Y. Katoh; A. Kohyama; S. Nishio; B. Riccardi; M. S. Tillack

2001-01-01

285

Phenomenology of major and minor disruptions in high ? deuterium and tritium tokamak fusion test reactor plasma  

NASA Astrophysics Data System (ADS)

The main subject of this work is the experimental study of the low m and n magnetohydrodynamics (MHD) perturbations during disruptive instability. This work presents the magnetic probe data, electron cyclotron emission (ECE), ?-particle losses, and neutron flux data measured during the disruptive instability in high ? tokamak fusion test reactor (TFTR) [D. J. Grove and D. M. Meade, Nucl. Fusion 25, 1167 (1985)] plasmas. The major disruptions in high ? regimes go through several phases. The first phase is the fast (150-250 ?s) minor disruption (predisruption), causing a drop of the central temperature (and possibly, density). In this phase a powerful central m=1/n=1 mode initiates the sequential development of m=4/n=1, 3/1, 2/1, 3/2 peripheral modes, which lead to a 3/1 locked mode. The second phase is the slow thermal quench (2 ms) in the presence of a locked mode. The third phase is a fast positive current spike generation (5%-10% increase in Ip in less than 0.5 ms) and finally, the current quench occurs with a loss of 2.5 MA in 5 ms.

Mirnov, S.; Semenov, I.; Fredrickson, E.; Budny, R.; Chang, Z.; McGuire, K.; Park, H.; Takahashi, H.; Taylor, G.; von Goeler, S.; Zakharov, L.; Zweben, S.

1998-11-01

286

Use of wavelet high-frequency substitution fusion to increase remote sensing image spatial resolution  

NASA Astrophysics Data System (ADS)

IHS transform was one of typical method for remote sensing data fusion. In recent years, newly developed method that combines advantages of IHS and Wavelet algorithms makes image fusion. In this case after the Wavelet substitution based on pixels or features, and then transforms inversely with IHS in Munsell color space. In this paper we introduce a high frequency substitution method to improve spatial resolutions of imagery. The procedure of the method introduced as flowchart, in which the dot line area is our newly added method. The resolution was greatly improved comparing original image. In cooperating with the demand of on going Minjiang river, Si Chuan, China. A 15m resolution PAN band and 30m resolution 7 bands of ETM data were selected for the method testing, the steps of method test showing in flow chart of this paper. In the future the dots area was our newly developed wavelet high frequency substitute. Improved NDVI imagery raised the quality for monitoring land cover change factor in the project of Return Farmland Back to Forest or Grassland.

Bagan, Hasi; Ma, Jianwen; Li, Qiqing; Liu, Zhili; Han, Xiuzhen

2003-09-01

287

Rocket-driven liners for fusion triggers and for very-high-density reactors  

Microsoft Academic Search

A simple theory of liner propulsion by material removed from the outer surface of the liner is outlined. It is shown that such liners should be able to compress and heat fusionable targets up to values of interest for pulsed thermonuclear fusion. Several conditions necessary for the achievement of fusion-power generation are discussed.

J. G. Linhart

1973-01-01

288

Direct integration multiple collision integral transport analysis method for high energy fusion neutronics  

Microsoft Academic Search

A new analysis method specially suited for the inherent difficulties of fusion neutronics was developed to provide detailed studies of the fusion neutron transport physics. These studies should provide a better understanding of the limitations and accuracies of typical fusion neutronics calculations. The new analysis method is based on the direct integration of the integral form of the neutron transport

Koch

1985-01-01

289

Complete saccharification of cellulose at high temperature using endocellulase and beta-glucosidase from Pyrococcus sp.  

PubMed

We investigated a potential for glucose production from cellulose material using two kinds of hyperthermophilic enzymes, endo-cellulase (EG) and beta-glucosidase (BGL). Two BGLs from hyperthermophile Pyrococcus furiosus and mesophile Aspergillus aculeatus were compared for complete hydrolysis of cellulose with P. horikoshii endo-cellulase (EGPh). The combination reactions by each BGL enzyme and EGPh could produce only glucose without the other oligosaccharides from phosphoric acid swollen Avicel (PSA). The combination of the both hyperthermophilic cellulases, BGLPf and EGPh, will be adaptable to high efficient system to produce glucose at high temperature. PMID:20519912

Kim, Han-Woo; Ishikawa, Kazuhiko

2010-05-01

290

Onset of Hydrodynamic Mix in High-Velocity, Highly Compressed Inertial Confinement Fusion Implosions  

NASA Astrophysics Data System (ADS)

Deuterium-tritium inertial confinement fusion implosion experiments on the National Ignition Facility have demonstrated yields ranging from 0.8 to 7×1014, and record fuel areal densities of 0.7 to 1.3g/cm2. These implosions use hohlraums irradiated with shaped laser pulses of 1.5-1.9 MJ energy. The laser peak power and duration at peak power were varied, as were the capsule ablator dopant concentrations and shell thicknesses. We quantify the level of hydrodynamic instability mix of the ablator into the hot spot from the measured elevated absolute x-ray emission of the hot spot. We observe that DT neutron yield and ion temperature decrease abruptly as the hot spot mix mass increases above several hundred ng. The comparison with radiation-hydrodynamic modeling indicates that low mode asymmetries and increased ablator surface perturbations may be responsible for the current performance.

Ma, T.; Patel, P. K.; Izumi, N.; Springer, P. T.; Key, M. H.; Atherton, L. J.; Benedetti, L. R.; Bradley, D. K.; Callahan, D. A.; Celliers, P. M.; Cerjan, C. J.; Clark, D. S.; Dewald, E. L.; Dixit, S. N.; Döppner, T.; Edgell, D. H.; Epstein, R.; Glenn, S.; Grim, G.; Haan, S. W.; Hammel, B. A.; Hicks, D.; Hsing, W. W.; Jones, O. S.; Khan, S. F.; Kilkenny, J. D.; Kline, J. L.; Kyrala, G. A.; Landen, O. L.; Le Pape, S.; MacGowan, B. J.; Mackinnon, A. J.; MacPhee, A. G.; Meezan, N. B.; Moody, J. D.; Pak, A.; Parham, T.; Park, H.-S.; Ralph, J. E.; Regan, S. P.; Remington, B. A.; Robey, H. F.; Ross, J. S.; Spears, B. K.; Smalyuk, V.; Suter, L. J.; Tommasini, R.; Town, R. P.; Weber, S. V.; Lindl, J. D.; Edwards, M. J.; Glenzer, S. H.; Moses, E. I.

2013-08-01

291

Onset of hydrodynamic mix in high-velocity, highly compressed inertial confinement fusion implosions.  

PubMed

Deuterium-tritium inertial confinement fusion implosion experiments on the National Ignition Facility have demonstrated yields ranging from 0.8 to 7×10^{14}, and record fuel areal densities of 0.7 to 1.3??g/cm^{2}. These implosions use hohlraums irradiated with shaped laser pulses of 1.5-1.9 MJ energy. The laser peak power and duration at peak power were varied, as were the capsule ablator dopant concentrations and shell thicknesses. We quantify the level of hydrodynamic instability mix of the ablator into the hot spot from the measured elevated absolute x-ray emission of the hot spot. We observe that DT neutron yield and ion temperature decrease abruptly as the hot spot mix mass increases above several hundred ng. The comparison with radiation-hydrodynamic modeling indicates that low mode asymmetries and increased ablator surface perturbations may be responsible for the current performance. PMID:24010449

Ma, T; Patel, P K; Izumi, N; Springer, P T; Key, M H; Atherton, L J; Benedetti, L R; Bradley, D K; Callahan, D A; Celliers, P M; Cerjan, C J; Clark, D S; Dewald, E L; Dixit, S N; Döppner, T; Edgell, D H; Epstein, R; Glenn, S; Grim, G; Haan, S W; Hammel, B A; Hicks, D; Hsing, W W; Jones, O S; Khan, S F; Kilkenny, J D; Kline, J L; Kyrala, G A; Landen, O L; Le Pape, S; Macgowan, B J; Mackinnon, A J; Macphee, A G; Meezan, N B; Moody, J D; Pak, A; Parham, T; Park, H-S; Ralph, J E; Regan, S P; Remington, B A; Robey, H F; Ross, J S; Spears, B K; Smalyuk, V; Suter, L J; Tommasini, R; Town, R P; Weber, S V; Lindl, J D; Edwards, M J; Glenzer, S H; Moses, E I

2013-08-23

292

H-alpha/H-beta and Optical Monitoring of High Mass X-ray Binary Systems  

NASA Astrophysics Data System (ADS)

We have developed a new fully calibrated H-alpha index, defined on both spectroscopic and photometric measurements of bright stars. Using the new H-alpha index, along with the traditional H-beta index, and optical broad band filters, we have monitored a set of High Mass X-ray Binary systems. In a number of cases we have seen significant variation in the H-alpha index, while there is limited variation in H-beta and/or the broad band filters. In one extreme case we see a 0.5 magnitude change in the H-alpha index in only 45 minutes, while H-beta and the optical flux remain constant. We will present results for a number of systems including 4U 2206+54, 1H 1936+541, 1H 2202+501, 4U 1956+35, IGR J00370+6122, RX J0440.9+4421, RX J2030.5+4751, and XTE J0421+560. This work is partially supported by NSF Grant AST-0618209. We also acknowledge use of the facilities of the Dominion Astrophysical Observatory.

Hintz, Eric G.; Joner, M. D.

2012-05-01

293

Seeding-dependent propagation and maturation of beta2-microglobulin amyloid fibrils under high pressure.  

PubMed

High hydrostatic pressure reversibly transforms the amyloid fibrils of beta2-microglobulin (beta2-m) into a more tightly packed, reorganized structure, which has provided insight into the polymorphic properties of amyloid fibrils. Here, to further investigate the molecular mechanism that controls fibril structure, seed-dependent fibril growth from an acid-unfolded monomeric form under high pressure was studied. At all pressures up to 400 MPa, the fibril growth could be approximated by a single-exponential kinetics, although pressure above 300 MPa decreased the growth rate significantly. The fibrils formed at high pressure were similar to the reorganized fibrils formed initially at ambient pressure and then pressurized, suggesting that the reorganized fibrils were formed directly at high pressure. A systematic investigation of the extension rate under various pressures indicated that the activation free energies for the original and reorganized fibrils are significantly different, suggesting that different amino acid contacts are involved in these two types of fibrils. On the other hand, for the seed-dependent extension reactions of both types of fibrils, the activation volume was much smaller than the change in reaction volume, implying that only small numbers of side-chain interactions are achieved in the transition state. Importantly, we observed a marked acceleration of fibril growth, i.e., maturation, on repeated self-seeding above 300 MPa, revealing the coexistence of another type of fibril with a similar structure but with an increased growth-rate under high pressure. PMID:16697008

Chatani, Eri; Naiki, Hironobu; Goto, Yuji

2006-04-25

294

High-Pressure Raman and X-ray Diffraction Study of [beta]- and [gamma]-Polymorphs of Aluminum Hydride  

SciTech Connect

Three polymorphs of alane, AlH{sub 3}, ({alpha}, {beta}, and {gamma}) were synthesized and studied at high-pressure in diamond anvil cell by Raman spectroscopy and synchrotron X-ray diffraction. According to synchrotron X-ray diffraction study, {beta}-AlH{sub 3} is stable up to 6 GPa, followed by transformation into {alpha} phase at higher pressures. X-ray-induced decomposition {gamma}-AlH{sub 3} into constituent elements was found at 15 GPa. Raman scattering study at high pressure for both {beta}- and {gamma}-AlH{sub 3} reveals transition into the {alpha} phase with high concentration of structural defects. DFT calculations (VASP code) show that instability of cubic {beta}-alane crystal structure at high pressure is caused by the strong deformation of the [AlH{sub 6}] polyhedra.

Drozd, Vadym; Garimella, Subrahmanyam; Saxena, Surendra; Chen, Jiuhua; Palasyuk, Taras (FIU); (IPC-Romania)

2012-03-26

295

HYFIRE II: fusion/high-temperature electrolysis conceptual-design study. Annual report  

SciTech Connect

As in the previous HYFIRE design study, the current study focuses on coupling a Tokamak fusion reactor with a high-temperature blanket to a High-Temperature Electrolyzer (HTE) process to produce hydrogen and oxygen. Scaling of the STARFIRE reactor to allow a blanket power to 6000 MW(th) is also assumed. The primary difference between the two studies is the maximum inlet steam temperature to the electrolyzer. This temperature is decreased from approx. 1300/sup 0/ to approx. 1150/sup 0/C, which is closer to the maximum projected temperature of the Westinghouse fuel cell design. The process flow conditions change but the basic design philosophy and approaches to process design remain the same as before. Westinghouse assisted in the study in the areas of systems design integration, plasma engineering, balance-of-plant design, and electrolyzer technology.

Fillo, J.A. (ed.)

1983-08-01

296

Use of Polycarbonate Vacuum Vessels in High-Temperature Fusion-Plasma Research  

SciTech Connect

Magnetic fusion energy (MFE) research requires ultrahigh-vacuum (UHV) conditions, primarily to reduce plasma contamination by impurities. For radiofrequency (RF)-heated plasmas, a great benefit may accrue from a non-conducting vacuum vessel, allowing external RF antennas which avoids the complications and cost of internal antennas and high-voltage high-current feedthroughs. In this paper we describe these and other criteria, e.g., safety, availability, design flexibility, structural integrity, access, outgassing, transparency, and fabrication techniques that led to the selection and use of 25.4-cm OD, 1.6-cm wall polycarbonate pipe as the main vacuum vessel for an MFE research device whose plasmas are expected to reach keV energies for durations exceeding 0.1 s

B. Berlinger, A. Brooks, H. Feder, J. Gumbas, T. Franckowiak and S.A. Cohen

2012-09-27

297

Reaching High-Yield Fusion with a Slow Plasma Liner Compressing a Magnetized Target  

SciTech Connect

Dynamics of the compression of a magnetized plasma target by a heavy liner made of partially ionized high high-Z material is discussed. A 'soft-landing' (shockless) mode of the liner deceleration is analyzed. Conclusion is drawn that such mode is possible for the liners whose thickness at the time of the first contact with the target is smaller than, roughly, 10% of the initial (un-compressed) target radius. A combination of the plasma liner with one or two glide cones allows for a direct access to the area near the center of the reactor chamber. One can then generate plasma target inside the plasma liner at the optimum time. The other advantage of the glide cones is that they can be used to deliver additional fuel to the center of the target near the point of a maximum compression and thereby increase the fusion yield.

Ryutov, D D; Parks, P B

2008-03-18

298

Application of spatially resolved high resolution crystal spectrometry to inertial confinement fusion plasmas  

NASA Astrophysics Data System (ADS)

High resolution (?/?? ~ 10 000) 1D imaging x-ray spectroscopy using a spherically bent crystal and a 2D hybrid pixel array detector is used world wide for Doppler measurements of ion-temperature and plasma flow-velocity profiles in magnetic confinement fusion plasmas. Meter sized plasmas are diagnosed with cm spatial resolution and 10 ms time resolution. This concept can also be used as a diagnostic of small sources, such as inertial confinement fusion plasmas and targets on x-ray light source beam lines, with spatial resolution of micrometers, as demonstrated by laboratory experiments using a 250-?m 55Fe source, and by ray-tracing calculations. Throughput calculations agree with measurements, and predict detector counts in the range 10-8-10-6 times source x-rays, depending on crystal reflectivity and spectrometer geometry. Results of the lab demonstrations, application of the technique to the National Ignition Facility (NIF), and predictions of performance on NIF will be presented.

Hill, K. W.; Bitter, M.; Delgado-Aparacio, L.; Pablant, N. A.; Beiersdorfer, P.; Schneider, M.; Widmann, K.; Sanchez del Rio, M.; Zhang, L.

2012-10-01

299

Application of spatially resolved high resolution crystal spectrometry to inertial confinement fusion plasmas  

SciTech Connect

High resolution ({lambda}/{Delta}{lambda}{approx} 10 000) 1D imaging x-ray spectroscopy using a spherically bent crystal and a 2D hybrid pixel array detector is used world wide for Doppler measurements of ion-temperature and plasma flow-velocity profiles in magnetic confinement fusion plasmas. Meter sized plasmas are diagnosed with cm spatial resolution and 10 ms time resolution. This concept can also be used as a diagnostic of small sources, such as inertial confinement fusion plasmas and targets on x-ray light source beam lines, with spatial resolution of micrometers, as demonstrated by laboratory experiments using a 250-{mu}m {sup 55}Fe source, and by ray-tracing calculations. Throughput calculations agree with measurements, and predict detector counts in the range 10{sup -8}-10{sup -6} times source x-rays, depending on crystal reflectivity and spectrometer geometry. Results of the lab demonstrations, application of the technique to the National Ignition Facility (NIF), and predictions of performance on NIF will be presented.

Hill, K. W.; Bitter, M.; Delgado-Aparacio, L.; Pablant, N. A. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Beiersdorfer, P.; Schneider, M.; Widmann, K. [Physics Division, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Sanchez del Rio, M. [European Synchrotron Radiation Facility, BP 220, 38043-Grenoble Cedex (France); Zhang, L. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

2012-10-15

300

Progress in laboratory high gain ICF (inertial confinement fusion): Prospects for the future  

SciTech Connect

Inertial confinement fusion (ICF), a thermonuclear reaction in a small (/approximately/5 mm diameter) fuel capsule filled with a few milligrams of deuterium and tritium, has been the subject of very fruitful experimentation since the early 1970's. High gain ICF is now on the threshold of practical applications. With a Laboratory Microfusion Facility (LMF), these applications will have major implications for national defense, basic and applied science, and power production. With a driver capable of delivering about 10 MJ in a 10-ns pulse at an intensity of /approximately/3 /times/ 10/sup 14/ W/cm/sup 2/, an appropriately configured cryogenic capsule could be compressed to a density of about 200 g/cm/sup 3/ and a temperature of 3--5 keV. Under these conditions, up to 10 mg of DT could be ignited, and with a burn efficiency of about 30%, release up to 1000 MJ of fusion energy, an energy gain of about 100. A thousand megajoules is equivalent to about one quarter ton of TNT, or about 7 gallons of oil--an amount of energy tractable under laboratory conditions and potentially very useful for a variety of applications. 61 refs., 33 figs.

Storm, E.; Lindl, J.D.; Campbell, E.M.; Bernat, T.P.; Coleman, L.W.; Emmett, J.L.; Hogan, W.J.; Hunt, J.T.; Krupke, W.F.; Lowdermilk, W.H.

1988-01-01

301

High-level multifunction radar simulation for studying the performance of multisensor data fusion systems  

NASA Astrophysics Data System (ADS)

This paper presents the basic requirements for a simulation of the main capabilities of a shipborne MultiFunction Radar (MFR) that can be used in conjunction with other sensor simulations in scenarios for studying Multi Sensor Data Fusion (MSDF) systems. This simulation is being used to support an ongoing joint effort (Canada - The Netherlands) in the development of MSDF testbeds. This joint effort is referred as Joint-FACET (Fusion Algorithms & Concepts Exploration Testbed), a highly modular and flexible series of applications that is capable of processing both real and synthetic input data. The question raised here is how realistic should the sensor simulations be to trust the MSDF performance assessment? A partial answer to this question is that at least, the dominant perturbing effects on sensor detection (true or false) are sufficiently represented. Following this philosophy, the MFR model, presented here, takes into account sensor's design parameters and external environmental effects such as clutter, propagation and jamming. Previous radar simulations capture most of these dominant effects. In this paper the emphasis is on an MFR scheduler which is the key element that needs to be added to the previous simulations to represent the MFR capability to search and track a large number of targets and at the same time support a large number of (semi-active) surface-to-air missiles (SAM) for the engagement of multiple hostile targets.

Huizing, Albert; Bosse, Eloi

1998-07-01

302

High-power corrugates waveguide components for mm-wave fusion heating systems  

SciTech Connect

Considerable progress has been made over the last year in the U.S., Japan, Russia, and Europe in developing high power long pulse gyrotrons for fusion plasma heating and current drive. These advanced gyrotrons typically operate at a frequency in the range 82 GHz to 170 GHz at nearly megawatt power levels for pulse lengths up to 5 s. To take advantage of these new microwave sources for fusion research, new and improved transmission line components are needed to reliably transmit microwave power to plasmas with minimal losses. Over the last year, General Atomics and collaborating companies (Spinner GmbH in Europe and Toshiba Corporation in Japan) have developed a wide variety of new components which meet the demanding power, pulse length, frequency, and vacuum requirements for effective utilization of the new generation of gyrotrons. These components include low-loss straight corrugated waveguides, miter bends, miter bend polarizers, power monitors, waveguide bellows, de breaks, waveguide switches, dummy loads, and distributed windows. These components have been developed with several different waveguide diameters (32, 64, and 89 mm) and frequency ranges (82 GHz to 170 GHz). This paper describes the design requirements of selected components and their calculated and measured performance characteristics.

Olstad, R.A.; Doane, J.L.; Moeller, C.P.; O`Neill, R.C.; Di Martino, M.

1996-10-01

303

Application of spatially resolved high resolution crystal spectrometry to inertial confinement fusion plasmas.  

PubMed

High resolution (???? ? 10 000) 1D imaging x-ray spectroscopy using a spherically bent crystal and a 2D hybrid pixel array detector is used world wide for Doppler measurements of ion-temperature and plasma flow-velocity profiles in magnetic confinement fusion plasmas. Meter sized plasmas are diagnosed with cm spatial resolution and 10 ms time resolution. This concept can also be used as a diagnostic of small sources, such as inertial confinement fusion plasmas and targets on x-ray light source beam lines, with spatial resolution of micrometers, as demonstrated by laboratory experiments using a 250-?m (55)Fe source, and by ray-tracing calculations. Throughput calculations agree with measurements, and predict detector counts in the range 10(-8)-10(-6) times source x-rays, depending on crystal reflectivity and spectrometer geometry. Results of the lab demonstrations, application of the technique to the National Ignition Facility (NIF), and predictions of performance on NIF will be presented. PMID:23126946

Hill, K W; Bitter, M; Delgado-Aparacio, L; Pablant, N A; Beiersdorfer, P; Schneider, M; Widmann, K; Sanchez del Rio, M; Zhang, L

2012-10-01

304

Studies on heavy ion fusion and high energy density physics in Japan  

NASA Astrophysics Data System (ADS)

In this paper, significant progresses of Japanese research activities are presented in heavy ion fusion (HIF) and high energy density physics (HEDP). Heavy ion beam (HIB) is a prominent tool to study HEDP and HIF, and HIBs may be a promising inertial fusion driver. HIB accelerators have been studied intensively for a long time; HIB pulse profile, a particle energy and a HIB quality are controllable. A HIB energy deposition profile is also well defined, and HIB energy is deposited inside a material. By focusing and using the HIB excellent properties, Japanese HIF and HEDP activities have covered a wide variety of subjects ranging from new accelerators to future HIF studies: ion source, new inductive accelerator, beam physics, beam bunching, beam instabilities, HIB interactions with gas or materials, laser ion acceleration, HIB transport, HIB-based warm dense (WD) state generation, new measurement of HED or WD matters, HIB stopping power, atomic physics, multi-HIBs illumination on a target, HIF target implosion, impact ignition scheme, HIB-radiation conversion, radiation confinement and transport in HED matter or in HIF, and so on.

Kawata, S.; Horioka, K.; Murakami, M.; Oguri, Y.; Hasegawa, J.; Takayama, K.; Yoneda, H.; Miyazawa, K.; Someya, T.; Ogoyski, A. I.; Seino, M.; Kikuchi, T.; Kawamura, T.; Ogawa, M.

2007-07-01

305

The National Ignition Facility Status and Plans for Laser Fusion and High Energy Density Experimental Studies  

NASA Astrophysics Data System (ADS)

The National Ignition Facility (NIF) currently under construction at the University of California Lawrence Livermore National Laboratory is 192-beam, 1.8 Megajoule, 500 Terawatt, 351 nm laser for inertial confinement fusion and high energy density experimental studies. NIF is being built by the Department of Energy and the National Nuclear Security Agency to provide an experimental test bed for the US Stockpile Stewardship Program to ensure the country’s nuclear deterrent without underground nuclear testing. The experimental program for NIF will encompass a wide range of physical phenomena from fusion energy production to materials science. Of the roughly 700 shots available per year, about 10% of the shots will be dedicated to basic science research. Additionally, most of the shots on NIF will be conducted in unclassified configurations that will allow participation from the greater scientific community in planned applied physics experiments. This presentation will provide a look at the status of the construction project as well as a description of the scientific uses of NIF. NIF is currently scheduled to provide first light in 2004 and will be completed in 2008. This work was performed under the auspices of the U.S. Department of Energy by University of California Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.

Wuest, Craig R.

2001-03-01

306

Multitemporal and multiresolution fusion of wide field of view and high spatial resolution images through morphological pyramid  

Microsoft Academic Search

To study vegetation from space, both high spatial resolution and high temporal frequency images are needed. However, a satellite sensor, for technological reasons, cannot provide such images. But merge several kinds of images coming from several sensors enables to overgo this problem. In this article, we propose a fusion method based on pyramid algorithms and on morphological filtering to create

Florence Laporterie-Dejean; Guy Flouzat; Erick Lopez-Ornelas

2004-01-01

307

Studies on a cooling of high heat flux surface in fusion reactor by impinging planar jet flow  

Microsoft Academic Search

Divertor surface of a fusion reactor is exposed to strong surface heating by high flux charged particles. According to typical design of ITER, the heat flux on divertor surface becomes locally near 20 MW m?2. Then, it is necessary to establish a cooling method to cool such high heat flux surface. A cooling by a planar impinging jet has been

A Inoue; A Ui; Y Yamazaki; H Matsusita; S. R Lee

2000-01-01

308

Quasilinear Evolution from Whistler and KAW Turbulence in the High Beta Solar Wind  

NASA Astrophysics Data System (ADS)

The electron and ion distribution functions resulting from quasi-linear diffusion in the turbulent solar wind plasma is calculated using the measured spectrum of the kinetic Alfven wave (KAW) fluctuations. Quasi-linear diffusion establishes a step-like profile on the distribution function over parallel velocity [1]. It is shown that the dispersion relation for whistler waves is identical for a high or low beta plasma. Furthermore in the high-beta solar wind plasma whistler waves meet the Landau resonance with electrons for velocities less than the thermal speed, and consequently the electric force is small compared to the mirror force. However, the whistlers are not damped since the background kinetic Alfven wave turbulence creates a plateau by quasilinear diffusion in the solar wind electron distribution at small velocities. The diffusion coefficient for whistlers in a high beta plasma is determined from mirror force, while the KAW diffusion is determined from the electric and mirror force. The size of ``plateau'' vme, which can be created within the time of travel of solar wind plasma to the Earth > 10^5 s, is estimated for electrons as vme/ve˜0.5. For a whistler spectrum similar to that of KAW, it is found that for whistler energy density of only ˜10-3 of the kinetic Alfven waves, the quasilinear diffusion rate due to whistlers and KAW are comparable. Thus very small amplitude whistler turbulence can have a significant consequence on the evolution of the solar wind electron distribution function. [1] L. Rudakov, M. Mithaiwala, G. Ganguli, and C. Crabtree. Phys. Plasmas 18, 012307 (2011)

Mithaiwala, Manish; Rudakov, Leonid; Ganguli, Gurudas; Crabtree, Chris

2012-10-01

309

High-beta studies with beam-heated, non-circular plasmas in ISX-B  

SciTech Connect

In this paper we describe some preliminary results of high beta studies on ISX-B for mildly D shaped discharges. ISX-B is a modest size tokamak (R/sub 0/ = 93 cm, a = 27 cm) equipped with two tangantially-aligned neutral beam injectors giving a total power up to 3 MW. The poloidal coil system allows choice of plasma boundary shapes from circular to elongated (kappa less than or equal to 1.8), with D, elliptical, or inverse D cross sections. The non-circular work discussed here is for kappa approx. = 1.5.

Lazarus, E.A.; Bates, S.C.; Bush, C.E.

1981-01-01

310

Limiter stabilization of high-beta external kink-tearing modes  

SciTech Connect

The stabilizing effects of finite-width poloidal limiters, toroidal limiters, and general mushroom limiters are examined for high-beta finite resistivity tokamak plamas in free boundary. When the plasma pressure and resistivity are small, a poloidal limiter is effective in reducing the growth rate even with a small limiter size, while a toroidal limiter requires a large size for a comparable effect. As the plasma pressure or resistivity increases, a toroidal limiter becomes more effective in reducing the growth rate than a poloidal limiter of the same size. A small optimized mushroom limiter might have a stabilizing effect similar to a conducting shell.

Lee, J.K.; Ohyabu, N.

1984-12-01

311

A Multi-beamlet High Current Injector for Heavy Ion Fusion  

NASA Astrophysics Data System (ADS)

Heavy ion fusion requires high current beams with high brightness. Thus the ion source and injector must produce, transport and match a space-charge dominated heavy ion beam into a transport channel of an induction linac. One way to overcome the space charge problem is to use small beamlets at low energy and then merge the beamlets, after gaining sufficient energy, to form a high current beam. Simulation had shown that the merged beam can have an acceptably low emittance. In a recently started experiment, we produced a high current beam (several 100 mA of Ar) by merging 119 high current density beamlets. The experiment is being done in two stages on a 500 kV test stand. We first tested the pre-accelerator at full voltage gradient to achieve high current density. In the second stage, the beamlets are converged to merge into an ESQ channel. Our goal is to confirm the emittance growth and to demonstrate the technical feasibility of building a driver-scale HIF injector. The experiment is scheduled to be completed by mid-FY05. Initial results will be presented.

Kwan, J. W.; Bieniosek, F. M.; Waldron, W. L.; Westenskow, G. A.; Grote, D. P.; Halaxa, E.

2004-11-01

312

Development of high power radio frequency components for fusion plasma heating. Final report, Revision 3  

SciTech Connect

The purpose of this CRADA was to develop advanced microwave heating systems for both ion cyclotron heating and electron cyclotron heating for magnetic fusion reactors. This involved low-frequency (UHF), high-power (millimeter-wave) microwave components, such as antennas, windows, and matching elements. This CRADA also involved developing conceptual designs for new microwave sources. General Atomics built and tested the distributed cooled window and provided LLNL with transmission and reflection test data in order to then benchmark the EM computer codes. The combline antenna built and analyzed by LLNL was based on a GA design. GA provided LLNL with a number of niobium plates for hot pressing and provided the necessary guidance to allow successful bonding. GA representatives were on site at LLNL on numerous occasions to consult and give guidance on the ferroelectric tuner, combline antenna and distributed window analysis.

NONE

1997-09-11

313

Improved-confinement plasmas at high temperature and high beta in the MST RFP  

SciTech Connect

We have increased substantially the electron and ion temperatures, the electron density, and the total beta in plasmas with improved energy confinement in the Madison Symmetric Torus (MST). The improved confinement is achieved with a well-established current profile control technique for reduction of magnetic tearing and reconnection. A sustained ion temperature > 1 keV is achieved with intensified reconnection-based ion heating followed immediately by current profile control. In the same plasmas, the electron temperature reaches 2 keV, and the electron thermal diffusivity drops to about 2 m(2) s(-1). The global energy confinement time is 12 ms. This and the reported temperatures are the largest values yet achieved in the reversed-field pinch (RFP). These results were attained at a density similar to 10(19) m(-3). By combining pellet injection with current profile control, the density has been quadrupled, and total beta has nearly doubled to a record value of about 26%. The Mercier criterion is exceeded in the plasma core, and both pressure-driven interchange and pressure-driven tearing modes are calculated to be linearly unstable, yet energy confinement is still improved. Transient momentum injection with biased probes reveals that global momentum transport is reduced with current profile control. Magnetic reconnection events drive rapid momentum transport related to large Maxwell and Reynolds stresses. Ion heating during reconnection events occurs globally, locally, or not at all, depending on which tearing modes are involved in the reconnection. To potentially augment inductive current profile control, we are conducting initial tests of current drive with lower-hybrid and electron-Bernstein waves.

Chapman, B. E. [University of Wisconsin, Madison; Ahn, J. W. [University of Wisconsin, Madison; Almagri, A. F. [University of Wisconsin, Madison; Anderson, J. [University of Wisconsin, Madison; Combs, Stephen Kirk [ORNL; Foust, Charles R [ORNL; Kaufman, M. [University of Wisconsin, Madison

2009-01-01

314

Magnetic fusion energy studies in Japan  

Microsoft Academic Search

The primary facility for magnetic fusion energy (MFE) research in Japan is JT-60, in which DD plasma is heated up to an electron temperature of Te>10keV with neutral beam injection (NBI) and radio frequency (RF) powers. It is noted that a normalized ?N of 2.3 was maintained for 22s. The JT-60 team has discovered internal transport barrier (ITB) in high-beta-poloidal

M. Ogawa; S. Tsuji-Iio; A. Komori; K. Kawahata; O. Kaneko; T. Inoue; Y. Kamada

2007-01-01

315

High-level production of human interleukin-10 fusions in tobacco cell suspension cultures.  

PubMed

The production of pharmaceutical proteins in plants has made much progress in recent years with the development of transient expression systems, transplastomic technology and humanizing glycosylation patterns in plants. However, the first therapeutic proteins approved for administration to humans and animals were made in plant cell suspensions for reasons of containment, rapid scale-up and lack of toxic contaminants. In this study, we have investigated the production of human interleukin-10 (IL-10) in tobacco BY-2 cell suspension and evaluated the effect of an elastin-like polypeptide tag (ELP) and a green fluorescent protein (GFP) tag on IL-10 accumulation. We report the highest accumulation levels of hIL-10 obtained with any stable plant expression system using the ELP fusion strategy. Although IL-10-ELP has cytokine activity, its activity is reduced compared to unfused IL-10, likely caused by interference of ELP with folding of IL-10. Green fluorescent protein has no effect on IL-10 accumulation, but examining the trafficking of IL-10-GFP over the cell culture cycle revealed fluorescence in the vacuole during the stationary phase of the culture growth cycle. Analysis of isolated vacuoles indicated that GFP alone is found in vacuoles, while the full-size fusion remains in the whole-cell extract. This indicates that GFP is cleaved off prior to its trafficking to the vacuole. On the other hand, IL-10-GFP-ELP remains mostly in the ER and accumulates to high levels. Protein bodies were observed at the end of the culture cycle and are thought to arise as a consequence of high levels of accumulation in the ER. PMID:23297698

Kaldis, Angelo; Ahmad, Adil; Reid, Alexandra; McGarvey, Brian; Brandle, Jim; Ma, Shengwu; Jevnikar, Anthony; Kohalmi, Susanne E; Menassa, Rima

2013-01-09

316

Highly efficient retrograde gene transfer into motor neurons by a lentiviral vector pseudotyped with fusion glycoprotein.  

PubMed

The development of gene therapy techniques to introduce transgenes that promote neuronal survival and protection provides effective therapeutic approaches for neurological and neurodegenerative diseases. Intramuscular injection of adenoviral and adeno-associated viral vectors, as well as lentiviral vectors pseudotyped with rabies virus glycoprotein (RV-G), permits gene delivery into motor neurons in animal models for motor neuron diseases. Recently, we developed a vector with highly efficient retrograde gene transfer (HiRet) by pseudotyping a human immunodeficiency virus type 1 (HIV-1)-based vector with fusion glycoprotein B type (FuG-B) or a variant of FuG-B (FuG-B2), in which the cytoplasmic domain of RV-G was replaced by the corresponding part of vesicular stomatitis virus glycoprotein (VSV-G). We have also developed another vector showing neuron-specific retrograde gene transfer (NeuRet) with fusion glycoprotein C type, in which the short C-terminal segment of the extracellular domain and transmembrane/cytoplasmic domains of RV-G was substituted with the corresponding regions of VSV-G. These two vectors afford the high efficiency of retrograde gene transfer into different neuronal populations in the brain. Here we investigated the efficiency of the HiRet (with FuG-B2) and NeuRet vectors for retrograde gene transfer into motor neurons in the spinal cord and hindbrain in mice after intramuscular injection and compared it with the efficiency of the RV-G pseudotype of the HIV-1-based vector. The main highlight of our results is that the HiRet vector shows the most efficient retrograde gene transfer into both spinal cord and hindbrain motor neurons, offering its promising use as a gene therapeutic approach for the treatment of motor neuron diseases. PMID:24086660

Hirano, Miyabi; Kato, Shigeki; Kobayashi, Kenta; Okada, Tomoaki; Yaginuma, Hiroyuki; Kobayashi, Kazuto

2013-09-24

317

Highly Efficient Retrograde Gene Transfer into Motor Neurons by a Lentiviral Vector Pseudotyped with Fusion Glycoprotein  

PubMed Central

The development of gene therapy techniques to introduce transgenes that promote neuronal survival and protection provides effective therapeutic approaches for neurological and neurodegenerative diseases. Intramuscular injection of adenoviral and adeno-associated viral vectors, as well as lentiviral vectors pseudotyped with rabies virus glycoprotein (RV-G), permits gene delivery into motor neurons in animal models for motor neuron diseases. Recently, we developed a vector with highly efficient retrograde gene transfer (HiRet) by pseudotyping a human immunodeficiency virus type 1 (HIV-1)-based vector with fusion glycoprotein B type (FuG-B) or a variant of FuG-B (FuG-B2), in which the cytoplasmic domain of RV-G was replaced by the corresponding part of vesicular stomatitis virus glycoprotein (VSV-G). We have also developed another vector showing neuron-specific retrograde gene transfer (NeuRet) with fusion glycoprotein C type, in which the short C-terminal segment of the extracellular domain and transmembrane/cytoplasmic domains of RV-G was substituted with the corresponding regions of VSV-G. These two vectors afford the high efficiency of retrograde gene transfer into different neuronal populations in the brain. Here we investigated the efficiency of the HiRet (with FuG-B2) and NeuRet vectors for retrograde gene transfer into motor neurons in the spinal cord and hindbrain in mice after intramuscular injection and compared it with the efficiency of the RV-G pseudotype of the HIV-1-based vector. The main highlight of our results is that the HiRet vector shows the most efficient retrograde gene transfer into both spinal cord and hindbrain motor neurons, offering its promising use as a gene therapeutic approach for the treatment of motor neuron diseases.

Hirano, Miyabi; Kato, Shigeki; Kobayashi, Kenta; Okada, Tomoaki; Yaginuma, Hiroyuki; Kobayashi, Kazuto

2013-01-01

318

High-level production of human interleukin-10 fusions in tobacco cell suspension cultures  

PubMed Central

The production of pharmaceutical proteins in plants has made much progress in recent years with the development of transient expression systems, transplastomic technology and humanizing glycosylation patterns in plants. However, the first therapeutic proteins approved for administration to humans and animals were made in plant cell suspensions for reasons of containment, rapid scale-up and lack of toxic contaminants. In this study, we have investigated the production of human interleukin-10 (IL-10) in tobacco BY-2 cell suspension and evaluated the effect of an elastin-like polypeptide tag (ELP) and a green fluorescent protein (GFP) tag on IL-10 accumulation. We report the highest accumulation levels of hIL-10 obtained with any stable plant expression system using the ELP fusion strategy. Although IL-10-ELP has cytokine activity, its activity is reduced compared to unfused IL-10, likely caused by interference of ELP with folding of IL-10. Green fluorescent protein has no effect on IL-10 accumulation, but examining the trafficking of IL-10-GFP over the cell culture cycle revealed fluorescence in the vacuole during the stationary phase of the culture growth cycle. Analysis of isolated vacuoles indicated that GFP alone is found in vacuoles, while the full-size fusion remains in the whole-cell extract. This indicates that GFP is cleaved off prior to its trafficking to the vacuole. On the other hand, IL-10-GFP-ELP remains mostly in the ER and accumulates to high levels. Protein bodies were observed at the end of the culture cycle and are thought to arise as a consequence of high levels of accumulation in the ER.

Kaldis, Angelo; Ahmad, Adil; Reid, Alexandra; McGarvey, Brian; Brandle, Jim; Ma, Shengwu; Jevnikar, Anthony; Kohalmi, Susanne E; Menassa, Rima

2013-01-01

319

Assembly of gag-beta-galactosidase proteins into retrovirus particles.  

PubMed Central

We studied the expression of beta-galactosidase (beta-gal) and 15 gag-beta-gal fusion proteins in the presence of Moloney murine leukemia virus wild-type core (gag) proteins. Analysis indicated that proteins retaining the amino-terminal portion of gag through the capsid protein-coding region were incorporated into retrovirus particles. Proteins which deleted portions of the capsid protein were assembled into virions at low efficiency, indicating the importance of capsid protein interactions in retrovirus assembly. Fusion proteins which retained the amino-terminal matrix protein of the gag polyprotein but which lacked the capsid protein were released efficiently from cells in a nonviral form. The nonviral form was characterized by a high sedimentation coefficient and a low density, suggestive of membrane vesicles. While beta-gal was present in the cytoplasm of expressing cells, all fusion constructs were associated with cellular membranes. gag-beta-gal proteins which were capable of release from cells demonstrated a two-component immunofluorescence staining pattern consisting of a circle of fluorescence around the nucleus and a punctate pattern of staining throughout the remainder of the cell. Interestingly, fusions within the matrix protein were trapped intracellularly and yielded distinct perinuclear staining patterns, possibly localizing to the rough endoplasmic reticulum and/or Golgi. This observation suggests that Moloney murine leukemia virus gag proteins travel to the plasma membrane by vesicular transport associated with the cytoplasmic face of intracellular vesicles. Images

Jones, T A; Blaug, G; Hansen, M; Barklis, E

1990-01-01

320

Some thoughts on the muon-catalyzed fusion process for antimatter propulsion and for the production of high A mass numbers antinuclei  

SciTech Connect

The muon-catalyzed fusion process has a very valuable role for antiproton science and technology. Several schemes of propulsion energy enhancement of the antiproton-fueled propulsion using the muon-catalyzed fusion are discussed. Production of high A mass antinuclei by the muon-catalyzed fusion using the clustered antihydrogen molecule and quark-gluon plasma formation by annihilation of the produced high A antimatter with regular nuclei are discussed. 22 refs., 2 figs., 1 tab.

Takahashi, Hiroshi

1987-01-01

321

ISEE 1 and 2 observations of the high beta shock. [Terrestrial bow shock  

SciTech Connect

Measurements from the ISEE 1 and ISEE 2 spacecraft are used to examine the terrestrial bow shock under high beta conditions. On November 4, 1979, the large separation between the spacecraft, over 2,500 km along the shock normal, was such to allow simultaneous upstream and downstream measurements of the solar wind plasma for a period of about 8 min. These measurements are compared with and found to be in agreement with the predicted values of the Rankine-Hugoniot relations using the simple adiabatic approximation and a ratio of specific heats, [gamma], of 5/3. No additional terms, such as the heat flux, are needed to bring the measured and predicted values in agreement. Large magnetic field and density fluctuations were observed, but average downstream plasma conditions well away from the shock were relatively steady, near the predicted Rankine-Hugoniot values. The magnetic disturbances persisted well downstream and a hot, dense ion beam was detected leaking from the downstream region of the shock. Both of these phenomena can be attributed to the excitation of the Alfven ion cyclotron instability, which acts quickly to isotropize the ions close to the ramp of the shock. Additional shock crossings under high beta conditions having smaller separations allow the authors to confirm many of these observations.

Farris, M.H.; Russell, C.T. (Univ. of California, Los Angeles (United States)); Thomsen, M.F.; Gosling, J.T. (Los Alamos National Lab., NM (United States))

1992-12-01

322

Magnetic fusion energy plasma interactive and high heat flux components. Volume 2: Technical assessment of the critical issues and problem areas in high heat flux materials and component development  

Microsoft Academic Search

A technical assessment of the critical issues and problem areas for high heat flux materials and components (HHFMC) in magnetic fusion devices shows these problems to be of critical importance for the successful operation of near-term fusion experiments and for the feasbility and attractiveness of long-term fusion reactors. Aspects considered include: (1) source conditions; (2) systems integration; (3) materials and

M. A. Abdou; R. D. Boyd; J. R. Easor; W. B. Gauster; J. D. Gordon; R. F. Mattas; G. D. Morgan; M. A. Ulrickson; R. D. Watson; W. G. Wolfer

1984-01-01

323

The national spherical torus experiment (NSTX) research programme and progress towards high beta, long pulse operating scenarios  

Microsoft Academic Search

A major research goal of the national spherical torus experiment is establishing long-pulse, high beta, high confinement operation and its physics basis. This research has been enabled by facility capabilities developed during 2001 and 2002, including neutral beam (up to 7 MW) and high harmonic fast wave (HHFW) heating (up to 6 MW), toroidal fields up to 6 kG, plasma

E. J. Synakowski; M. G. Bell; R. E. Bell; T. Bigelow; M. Bitter; W. Blanchard; J. Boedo; C. Bourdelle; C. Bush; D. S. Darrow; E. D. Fredrickson; D. A. Gates; M. Gilmore; L. R. Grisham; J. C. Hosea; D. W. Johnson; R. Kaita; S. M. Kaye; S. Kubota; H. W. Kugel; B. P. LeBlanc; K. Lee; R. Maingi; J. Manickam; R. Maqueda; E. Mazzucato; S. S. Medley; J. Menard; D. Mueller; B. A. Nelson; C. Neumeyer; M. Ono; F. Paoletti; H. K. Park; S. F. Paul; Y.-K. M. Peng; C. K. Phillips; S. Ramakrishnan; R. Raman; A. L. Roquemore; A. Rosenberg; P. M. Ryan; S. A. Sabbagh; C. H. Skinner; V. Soukhanovskii; T. Stevenson; D. Stutman; D. W. Swain; G. Taylor; A. Von Halle; J. Wilgen; M. Williams; J. R. Wilson; S. J. Zweben; R. Akers; R. E. Barry; P. Beiersdorfer; J. M. Bialek; B. Blagojevic; P. T. Bonoli; R. Budny; M. D. Carter; C. S. Chang; J. Chrzanowski; W. Davis; B. Deng; E. J. Doyle; L. Dudek; J. Egedal; R. Ellis; J. R. Ferron; M. Finkenthal; J. Foley; E. Fredd; A. Glasser; T. Gibney; R. J. Goldston; R. Harvey; R. E. Hatcher; R. J. Hawryluk; W. Heidbrink; K. W. Hill; W. Houlberg; T. R. Jarboe; S. C. Jardin; H. Ji; M. Kalish; J. Lawrance; L. L. Lao; K. C. Lee; F. M. Levinton; N. C. Luhmann; R. Majeski; R. Marsala; D. Mastravito; T. K. Mau; B. McCormack; M. M. Menon; O. Mitarai; M. Nagata; N. Nishino; M. Okabayashi; G. Oliaro; D. Pacella; R. Parsells; T. Peebles; B. Peneflor; D. Piglowski; R. Pinsker; G. D. Porter; A. K. Ram; M. Redi; M. Rensink; G. Rewoldt; J. Robinson; P. Roney; M. Schaffer; K. Shaing; S. Shiraiwa; P. Sichta; D. Stotler; B. C. Stratton; Y. Takase; X. Tang; R. Vero; W. R. Wampler; G. A. Wurden; X. Q. Xu; J. G. Yang; L. Zeng; W. Zhu

2003-01-01

324

The National Spherical Torus Experiment (NSTX) research programme and progress towards high beta, long pulse operating scenarios  

Microsoft Academic Search

A major research goal of the national spherical torus experiment is establishing long-pulse, high beta, high confinement operation and its physics basis. This research has been enabled by facility capabilities developed during 2001 and 2002, including neutral beam (up to 7 MW) and high harmonic fast wave (HHFW) heating (up to 6 MW), toroidal fields up to 6 kG, plasma

D. W. Johnson; L. R. Grisham; S. J. Zweben; D. A. Gates; C. Bush; E. J. Synakowski; J. C. Hosea; W. Blanchard; Michael G. Bell; S. Sabbagh; V. Soukhanovskii; R. Raman; Y. K. M. Peng; M. Ono; T. Stevenson; E. D. Fredrickson; Shigeru Kubota; P. C. Efthimion; C. Bourdelle; J. R. Wilson; R. Maqueda; S. M. Kaye; R. Kaita; R. Maingi; D. S. Darrow; M. Bitter; Henry W. Kugel; C. H. Skinner; J. Wilgen; A. Von Halle; G. Taylor; D. Mueller; D. W. Swain; P. M. Ryan; A. Rosenberg; S. Ramakrishnan; C. K. Phillips; S. Paul; H. K. Park; F. Paoletti; J. Boedo; M. Williams; Mark A. Gilmore; B. LeBlanc; T. Bigelow; R. E. Bell; A. L. Roquemore; William R. Wampler; S. S. Medley; D. Stutman; J. Menard; E. Mazzucato; C. Neumeyer; B. A. Nelson; K. Lee; J. Manickam

2004-01-01

325

Numerical study of the Columbia high-beta device: Torus-II  

SciTech Connect

The ionization, heating and subsequent long-time-scale behavior of the helium plasma in the Columbia fusion device, Torus-II, is studied. The purpose of this work is to perform numerical simulations while maintaining a high level of interaction with experimentalists. The device is operated as a toroidal z-pinch to prepare the gas for heating. This ionization of helium is studied using a zero-dimensional, two-fluid code. It is essentially an energy balance calculation that follows the development of the various charge states of the helium and any impurities (primarily silicon and oxygen) that are present. The code is an atomic physics model of Torus-II. In addition to ionization, we include three-body and radiative recombination processes.

Izzo, R.

1981-01-01

326

(-)(125I)-iodopindolol, a new highly selective radioiodinated beta-adrenergic receptor antagonist: measurement of beta-receptors on intact rat astrocytoma cells  

SciTech Connect

(-)-Pindolol, one of the most potent beta-adrenergic receptor antagonists, was radioiodinated using chloramine-T oxidation of carrier-free Na 125I and separated from unreacted pindolol to yield 2200 Ci/mmole (-)-(125I)-iodopindolol ((-)-(125I)-IPin). Mass and ultraviolet spectra confirmed that the iodination occurred on the indole ring, presumably at the 3 position. The binding of radiolabeled (-)-(125I)-IPin to beta-adrenergic receptors has been studied using intact C6 rat astrocytoma cells (2B subclone) grown in monolayer cultures. Binding of (-)(125IPin was saturable with time and concentration. Using 13 pM (-)-(125I)IPin, binding equilibrium was reached in 90 min at 21-22 degrees C. The reverse rate constant was 0.026 min-1 at 21/sup 0/C. Specific binding (expressed as 1 microM(-)-propranolol displaceable counts) of (-)-(125I)-IPin was 95% of total binding. Scatchard analysis of (-)-(125I)-I)Pin binding revealed approximately 4300 receptors/cell and a dissociation constant of 30 pM. This was in excellent agreement with the kinetically determined dissociation constant of 35 pM. Displacement by propranolol and isoproterenol showed that (-)-(125I)-IPin binding sites were pharmacologically and stereospecifically selective. These results indicate that (-)-(125I)-IPin, a pure (-)-stereoisomer, high specific activity radioligand, selectively binds to beta-adrenergic receptors in whole cells with a high percentage of specific binding and should therefore be useful in the study and measurement of cellular beta-adrenergic receptors.

Barovsky, K.; Brooker, G.

1980-01-01

327

High-power-density approaches to magnetic fusion energy: problems and promise of compact Reversed-Field Pinch Reactors (CRFPR)  

SciTech Connect

If the costing assumptions upon which the positive assessment of conventional large superconducting fusion reactors are based proves overly optimistic, approaches that promise considerably increased system power density and reduced mass utilization will be required. These more compact reactor embodiments generally must operate with reduced shield thickness and resistive magnets. Because of the unique magnetic topology associated with the Reversed-Field Pinch (RFP), the compact reactor embodiment for this approach is particularly attractive from the view point of low-field resistive coils operating with Ohmic losses that can be made small relative to the fusion power. The RFP, therefore, is used as one example of a high-power-density (HPD) approach to magnetic fusion energy. A comprehensive system model is described and applied to select a unique, cost-optimized design point that will be used for a subsequent conceptual engineering design of the Compact RFP Reactor (CRFPR). This cost-optimized CRFPR design serves as an example of a HPD fusion reactor that would operate with system power densities and mass utilization that are comparable to fission power plants, these measures of system performance being an order of magnitude more favorable than the conventional approaches to magnetic fusion energy (MFE).

Hagenson, R.L.; Krakowski, R.A.; Dreicer, H.

1982-01-01

328

Demonstration of Radiation Pulse Shaping with Nested-Tungsten-Wire-Array Z Pinches for High-Yield Inertial Confinement Fusion  

SciTech Connect

Nested wire-array Z pinches are shown to generate soft x-ray radiation pulse shapes required for three-shock isentropic compression and hot-spot ignition of high-yield inertial confinement fusion capsules. We demonstrate a reproducible and tunable foot pulse (first shock) produced by interaction of the outer and inner arrays. A first-step pulse (second shock) is produced by inner array collision with a central CH{sub 2} foam target. Stagnation of the inner array at the axis produces the third shock. Capsules optimized for several of these shapes produce 290-900 MJ fusion yields in 1D simulations.

Cuneo, M.E.; Vesey, R.A.; Sinars, D.B.; Waisman, E.M.; Lemke, R.W.; Bliss, D.E.; Stygar, W.A.; Porter, J.L.; Mazarakis, M.G.; Chandler, G.A.; Mehlhorn, T.A. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1193 (United States); Chittenden, J.P.; Lebedev, S.V. [Blackett Laboratory, Imperial College, London SW7 2BW (United Kingdom); Schroen, D.G. [Schafer Corporation, Livermore, California 94550 (United States)

2005-10-28

329

Detection of highly enriched uranium and tungsten surface damage studies using a pulsed inertial electrostatic confinement fusion device  

Microsoft Academic Search

The research in this thesis examines two applications of a pulsed Inertial Electrostatic Confinement (EEC) fusion device: detection of highly enriched uranium (HEU) and tungsten surface damage studies. In order to complete this thesis, a pulsed IEC device was developed that is capable of generating converging ion pulses with widths ranging from 0.1 to 5 ms at frequencies between 1

Ross F. Radel

2007-01-01

330

Quality assessment of decision-driven pyramid-based fusion of high resolution multispectral with panchromatic image data  

Microsoft Academic Search

This work presents a general and formal solution to the problem of fusion of multispectral data with high-resolution panchromatic images. The method relies on the generalized Laplacian pyramid, which is an oversampled structure obtained by subtracting from an image its lowpass version, and selectively performs spatial-frequencies spectrum substitution from one image to another. The novelty of the present work is

Bruno Aiazzi; L. Alparone; S. Baronti; I. Pippi

2001-01-01

331

Cell fusion during yeast mating requires high levels of a-factor mating pheromone  

Microsoft Academic Search

During conjugation, two yeast cells fuse to form a single zygote. Cell fusion requires extensive re- modeling of the cell wall, both to form a seal between the two cells and to remove the intervening material. The two plasma membranes then fuse to produce a continuous cytoplasm. We report the characterization of two cell fusion defective (Fus-) mutants, fus5 and

Valeria Brizzio; Alison E. Gammie; Gaby Nijbroek; Susan Michaelis; Mark D. Rose

1996-01-01

332

Demountable low stress high field toroidal field magnet system for tokamak fusion reactors  

Microsoft Academic Search

A new type of superconducting magnet system for large fusion reactors is described in this report. Instead of winding large planar or multi-axis coils, as has been proposed in previous fusion reactor designs, the superconducting coils are made by joining together several prefabricated conductor sections. The joints can be unmade and sections removed if they fail. Conductor sections can be

J. Powell; D. Hsieh; J. Lehner; M. Suenaga

1977-01-01

333

Shape of Electrodes for High Performance of Inertial Electrostatic Confinement Fusion  

Microsoft Academic Search

Inertial electrostatic confinement (IEC) fusion is a scheme of producing deuterium, tritium, and helium-3 ions between the anode and the hollow cathode in the concentric sphere by glow discharge, accelerating the ions into the spherical center and giving rise to the fusion reactions between the accelerated ions or between the accelerated ions and the background neutrals. The current feed-through is

Masami OHNISHI; Hodaka OSAWA; Ryo TANAKA; Naoki WAKIZAKA

2005-01-01

334

Optimal shape of electrodes for high performance of inertial electrostatic confinement fusion  

Microsoft Academic Search

Inertial electrostatic confinement (IEC) fusion is a scheme of producing the ions between the anode and the hollow cathode in the concentric spheres by the glow discharge, accelerating the ions into the spherical center and giving rise to fusion reactions between the accelerated ions or between the accelerated ions and the background neutrals. A current feed-through is connected to the

R. Tanaka; H. Osawa; T. Tabata; T. Ishibashi; M. Ohnishi

2003-01-01

335

Magnetospheres in the Labtoratory: Studying the Role of Ion Temperature Anisotropy in High Beta Plasmas  

NASA Astrophysics Data System (ADS)

The wide range of plasma regimes in the near-Earth space environment provide unparalleled opportunities for testing the predictions of theory and computation. Measurements and theory have yielded substantial insight into the macroscopic dynamics and structure of the terrestrial ionosphere, magnetosphere, and magnetotail, as well as of the solar wind. Unfortunately, nature's price for providing such a rich plasma environment is that the scientific paradigm of varying a single parameter in a controlled experiment and determining the consequences is extremely difficult to achieve in space plasma research. Thus, progress in understanding microscopic aspects of space plasmas has been more equivocal. This talk will focus on studies of electromagnetic ion temperature anisotropy driven instabilities in high beta, marginally collisional, magnetized plasmas. The experiments were performed in the West Virginia University Large Experiment on Anisotropies and Instabilities (LEIA). Typical steady state, LEIA argon plasma parameters are n ~ 10E12 cm-3, B ~ 40 G, electron temperature ~ 5 eV, parallel ion temperature ~ 0.2 eV, perpendicular ion temperature ~ 0.6 eV, electron beta ~ 0.1 , and parallel ion beta ~ 0.01. The parallel and perpendicular ion temperatures are determined by laser induced fluorescence. Radially resolved, two dimensional(parallel and perpendicular to the field) measurements of the ion distribution function are also routinely measured. Ion temperatures anisotropies (perpendicular over parallel) ranging from 1 to 20 have been observed and the upper bound on the anisotropy is observed to be inversely correlated with parallel ion beta as predicted by theory and computation. The inverse scaling of the upper bound on the ion temperature anisotropy is also consistent with magnetosheath observations by multiple spacecraft. Magnetic fluctuation measurements support the conclusion that anisotropy driven, electromagnetic instabilities exist in the plasma and that they play a role in limiting the ion temperature anisotropy. The experimental results also suggest that such constraints may be a fundamental property of all collisionless plasmas bearing such an anisotropy, including other laboratory plasmas as well as space and astrophysical domains not yet subject to in situ observations. Thus, the basic concept of short wavelength instabilities imposing anisotropy constraints may offer an alternative to the long-standing approach of using analogues of collision-dominated transport coefficients to express the consequences of small-scale, collective processes in the collisionless plasmas of space. This work supported by the National Science Foundation under grant ATM-9616467 and the U.S. Department of Energy under grant DE-FG02-97ER54420

Scime, Earl

1999-11-01

336

High-speed surface temperature measurements on plasma facing materials for fusion applications  

SciTech Connect

For the lifetime evaluation of plasma facing materials in fusion experimental machines, it is essential to investigate their surface behavior and their temperature responses during an off-normal event such as the plasma disruptions. An infrared thermometer with a sampling speed as fast as 1{times}10{sup {minus}6} s/data, namely, the high-speed infrared thermometer (HSIR), has been developed by the National Research Laboratory of Metrology in Japan. To evaluate an applicability of the newly developed HSIR on the surface temperature measurement of plasma facing materials, high heat flux beam irradiation experiments have been performed with three different materials under the surface heat fluxes up to 170 MW/m{sup 2} for 0.04 s in a hydrogen ion beam test facility at the Japan Atomic Energy Research Institute. As for the results, HSIR can be applicable for measuring the surface temperature responses of the armor tile materials with a little modification. It is also confirmed that surface temperatures measured with the HSIR thermometer show good agreement with the analytical results for stainless steel and carbon based materials at a temperature range of up to 2500{degree}C. However, for aluminum the HSIR could measure the temperature of the high dense vapor cloud which was produced during the heating due to lower melting temperature. Based on the result, a multichannel arrayed HSIR thermometer has been designed and fabricated. {copyright} {ital 1996 American Institute of Physics.}

Araki, M. [Naka Fusion Research Establishment, Japan Atomic Energy Research Institute, 801-1, Naka-machi, Naka-gun, Ibaraki, 311-01 (Japan); Kobayashi, M. [Thermal Measurement Section, Thermophysical Metrology Department, National Research Laboratory of Metrology, 1-1-4, Umezono, Tsukuba, Ibaraki, 305 (Japan)

1996-01-01

337

Non-fossil energy for the production of synthetic fuels from coal. I. Fusion reactor with high temperature steam electrolyzer and gasifier  

Microsoft Academic Search

Fusion reactors could displace a large amount of the coal needed for synthetic fuel production. A unique feature of a fusion reactor is that it can potentially supply high temperature steam in the range of 1000° to 1500°C in a continuous manner. The high temperature steam would be obtained by internal heating of a refractory containing blanket section which would

Steinberg

1978-01-01

338

Non-fossil energy for the production of synthetic fuels from Coal I. Fusion reactor with high temperature steam electrolyzer and gasifier  

Microsoft Academic Search

Fusion reactors could displace a large amount of the coal needed for synthetic fuel production. A unique feature of a fusion reactor is that it can potentially supply high temperature steam in the range of 1000° to 1500°C in a continuous manner. The high temperature steam would be obtained by internal heating of a refractory containing blanket section which would

Steinberg

1980-01-01

339

Limited access surgery for 360 degrees in-situ fusion in a dysraphic patient with high-grade spondylolisthesis.  

PubMed

Progressive high-grade spondylolisthesis can lead to spinal imbalance. High-grade spondylolisthesis is often reduced and fused in unbalanced pelvises, whereas in-situ fusion is used more often in balanced patients. The surgical goal is to recreate or maintain sagittal balance but if anatomical reduction is necessary, the risk of nerval damage with nerve root disruption in worst cases is increased. Spinal dysraphism like spina bifida or tethered cord syndrome make it very difficult to achieve reduction and posterior fusion due to altered anatomy putting the focus on anterior column support. Intensive neural structure manipulation should be avoided to reduce neurological complications and re-tethering in these cases. A 26-year-old patient with a history of diastematomyelia, occult spina bifida and tethered cord syndrome presented with new onset of severe low back pain, and bilateral L5/S1 sciatica after a fall. The X-ray demonstrated a grade III spondylolisthesis with spina bifida and the MRI scan revealed bilateral severely narrowed exit foramina L5 due to the listhesis. Because she was well balanced sagittally, the decision for in-situ fusion was made to minimise the risk of neurological disturbance through reduction. Anterior fusion was favoured to minimise manipulation of the dysraphic neural structures. Fusion was achieved via isolated access to the L4/L5 disc space. A L5 transvertebral hollow modular anchorage (HMA) screw was passed into the sacrum from the L4/L5 disc space and interbody fusion of L4/L5 was performed with a cage. The construct was augmented with pedicle screw fixation L4-S1 via a less invasive bilateral muscle split for better anterior biomechanical support. The postoperative course was uneventful and fusion was CT confirmed at the 6-month follow-up. At the last follow-up, she worked full time, was completely pain free and not limited in her free-time activities. The simultaneous presence of high-grade spondylolisthesis and spinal dysraphism make it very difficult to find a decisive treatment plan because both posterior and anterior treatment strategies have advantages and disadvantages in these challenging cases. The described technique combines several surgical options to achieve 360° fusion with limited access, reducing the risk of neurological sequelae. PMID:22008862

König, M A; Boszczyk, B M

2011-10-19

340

Control of a high beta maneuvering reentry vehicle using dynamic inversion.  

SciTech Connect

The design of flight control systems for high performance maneuvering reentry vehicles presents a significant challenge to the control systems designer. These vehicles typically have a much higher ballistic coefficient than crewed vehicles like as the Space Shuttle or proposed crew return vehicles such as the X-38. Moreover, the missions of high performance vehicles usually require a steeper reentry flight path angle, followed by a pull-out into level flight. These vehicles then must transit the entire atmosphere and robustly perform the maneuvers required for the mission. The vehicles must also be flown with small static margins in order to perform the required maneuvers, which can result in highly nonlinear aerodynamic characteristics that frequently transition from being aerodynamically stable to unstable as angle of attack increases. The control system design technique of dynamic inversion has been applied successfully to both high performance aircraft and low beta reentry vehicles. The objective of this study was to explore the application of this technique to high performance maneuvering reentry vehicles, including the basic derivation of the dynamic inversion technique, followed by the extension of that technique to the use of tabular trim aerodynamic models in the controller. The dynamic inversion equations are developed for high performance vehicles and augmented to allow the selection of a desired response for the control system. A six degree of freedom simulation is used to evaluate the performance of the dynamic inversion approach, and results for both nominal and off nominal aerodynamic characteristics are presented.

Watts, Alfred Chapman

2005-05-01

341

Association analysis of retinoic acid receptor beta (RAR?) gene with high myopia in Chinese subjects  

PubMed Central

Purpose High myopia or pathological myopia is a common refractive error. Individuals with high myopia are subject to increased risk of serious eye complications. Accumulating evidence has demonstrated the role for heritability in ocular growth and in the development of high myopia. Retinoic acid and retinoic acid receptors play important roles in ocular development and in experimentally induced myopia. The purpose of this study was to determine if high myopia is associated with single nucleotide polymorphism (SNP) variants in the retinoic acid receptor beta (RAR?) gene in Chinese subjects. Methods DNA samples were purified from venous lymphocytes of 175 unrelated Chinese patients with high myopia (less than ?8.00 diopters) and 101 Chinese control subjects without high myopia (±1.00 diopters). Direct nucleotide sequence analysis in the RAR? gene was performed, and the detected variations were further confirmed by reverse sequencing. Allelic frequencies of all detected SNPs were assessed for Hardy–Weinberg equilibrium. Results Five variations in RAR? were detected in Chinese subjects with high myopia, including 32574G>A, 32629G>A, 32645C>T, 32647T>G, and 151973C>T, of which only 32647T>G (NCBI notes as rs58244688 and rs2067964) had already been reported. The majority of SNP genotypes were heterozygous. While 32647T>G, 32629G>A, and 32645C>T were located in introns and 32574G>A and 151973C>T were located in coding regions, none of the SNPs affected the amino acid sequence. In the present study, no evidence of association was found between variations in the nucleotide sequence of RAR? and high myopia. Conclusions Five SNP variants in RAR? were detected in Chinese subjects with high myopia, none of them were associated significantly with high myopia. Further studies are needed to identify which genes are responsible for high myopia.

Ding, Yang; Chen, Xiaoyan; Yan, Dongsheng; Xue, Anquan; Lu, Fan; Qu, Jia

2010-01-01

342

Highly bright X-ray generator using heat of fusion with a specially designed rotating anticathode  

PubMed Central

A new type of rotating anticathode X-ray generator has been developed, in which the electron beam irradiates the inner surface of a U-shaped anticathode (Cu). A high-flux electron beam is focused on the inner surface by optimizing the shape of the bending magnet. The power of the electron beam can be increased to the point at which the irradiated part of the inner surface is melted, because a strong centrifugal force fixes the melted part on the inner surface. When the irradiated part is melted, a large amount of energy is stored as the heat of fusion, resulting in emission of X-rays 4.3 times more brilliant than can be attained by a conventional rotating anticathode. Oscillating translation of the irradiated position on the inner surface during use is expected to be very advantageous for extending the target life. A carbon film coating on the inner surface is considered to suppress evaporation of the target metal and will be an important technique in further realization of highly bright X-ray generation.

Sakabe, N.; Ohsawa, S.; Sugimura, T.; Ikeda, M.; Tawada, M.; Watanabe, N.; Sasaki, K.; Ohshima, K.; Wakatsuki, M.; Sakabe, K.

2008-01-01

343

Overview of the scientific objectives of the high current experiment of heavy-ion fusion  

SciTech Connect

The High Current Experiment (HCX) is being built to explore heavy-ion beam transport at a scale appropriate to the low-energy end of a driver for fusion energy production. The primary mission of this experiment is to investigate aperture fill factors acceptable for the transport of space-charge dominated heavy-ion beams at high space-charge intensity (line-charge density {approx} 0.2 {micro}C/m) over long pulse durations (3-10 {micro}sec). A single beam transport channel will be used to evaluate scientific and technological issues resulting from the transport of an intense beam subject to applied field nonlinearities, envelope mismatch, misalignment-induced centroid excursions, imperfect vacuum, halo, background gas and electron effects resulting from lost beam ions. Emphasis will be on the influence of these effects on beam control and limiting degradations in beam quality (emittance growth). Electrostatic (Phase I) and magnetic (Phase II) quadrupole focusing lattices have been designed and future phases of the experiment may involve acceleration and/or pulse compression. The Phase I lattice is presently under construction [1] and simulations to better predict machine performance are being carried out [2]. Here we overview: the scientific objectives of the overall project, processes that will be explored, and transport lattices developed.

Seidl, P.; Bangerter, R.; Celata, C.; Faltens, A.; Karpenko, V.; Lee, E.; Haber, I.; Lund, S.; Molvik, A.

2001-06-01

344

Performance of large-aperture optical switches for high-energy inertial-confinement fusion lasers  

SciTech Connect

We describe the design and performance of large-aperture ({lt}30 cm {times} 30 cm) optical switches that have demonstrated, for the first time to our knowledge, active switching of a high-energy ({lt}5 kJ) optical pulse in an inertial-confinement fusion laser. These optical switches, which consist of a plasma-electrode Pockels cell (PEPC) and a passive polarizer, permit the design of efficient, multipass laser amplifiers. In a PEPC, plasma discharges on the faces of a thin (1-cm) electro-optic crystal (KDP or KD{bold |}P) act as highly conductive and transparent electrodes. These plasma electrodes facilitate rapid ({lt}100 ns) and uniform charging of the crystal to the half-wave voltage and discharging back to 0 V. We discuss the operating principles, design, optical performance, and technical issues of a 32 cm {times} 32 cm prototype PEPC with both KDP and KD{bold |}P crystals, and a 37 cm {times} 37 cm PEPC with a KDP crystal for the Beamlet laser. This PEPC recently switched a 6-kJ, 3-ns pulse in a four-pass cavity.

Rhodes, M.A.; Woods, B.; DeYoreo, J.J.; Roberts, D.; Atherton, L.J. [University of California, Lawrence Livermore National Laboratory, P.O. Box 808 L-490, Livermore, California 94550 (United States)

1995-08-20

345

Electron kinetic effects on interferometry and polarimetry in high temperature fusion plasmas  

NASA Astrophysics Data System (ADS)

At anticipated high electron temperatures in ITER, the effects of electron thermal motion on phase measurements made by the toroidal interferometer/polarimeter (TIP) and poloidal polarimeter (PoPola) diagnostics will be significant and must be precisely treated or the measurement accuracy will fail to meet the specified requirements for ITER operation. We calculate electron thermal corrections to the interferometric phase and polarization state of an electromagnetic wave propagating along tangential and poloidal chords (Faraday and Cotton-Mouton polarimetry) and incorporate them into the Stokes vector equation for evolution of polarization. Although these corrections are small at electron temperatures Te ? 1 keV, they become sizable at Te ? 10 keV. The precision of the previous lowest order linear in the ? = Te/mec2 model may be insufficient; we present a more precise model with ?2-order corrections to satisfy the high accuracy required for ITER TIP and PoPola diagnostics. Proper treatment of temperature effects will ensure more accurate interpretation of interferometric and polarimetric measurements in fusion devices like ITER and DEMO. The use of precise analytic expressions is especially important for burning plasmas where various interferometric techniques will be used for direct real time feedback control of device operations with time resolution ˜1 ms to regulate the rate of the thermonuclear burn and monitor/control the safety factor profile.

Mirnov, V. V.; Brower, D. L.; Den Hartog, D. J.; Ding, W. X.; Duff, J.; Parke, E.

2013-11-01

346

Production of High Current Density Beams for Heavy Ion Fusion Accelerators  

NASA Astrophysics Data System (ADS)

A typical heavy ion fusion driver consists of a multiple-beam induction linac system. At the front end there are 84 ESQ channels; each channel can transport a beam with line charge density of ? 0.25 ?C/m before compression. The maximum usable current density from the ion source is dictated by the space-charge-limited low energy beam transport (LEBT). The existing ion source developed for the ELISE/ILSE injector has a 6.7" diameter alumino-silicate emitter producing a current density of 3.5 mA/cm^2 of K^+ ions. Although this design has met the beam current and emittance requirements for the project, the overall cost of the single-beam injector (? $2M per copy) is too high for a 84-beam machine. In order to reduce cost, we consider the development of a multiple-beam injector using high current density ion sources. We will present experimental data in testing the emission limit of the surface source aiming at reaching 15 mA/cm^2 of K^+. Other important parameters include the current density uniformity, emittance and life time. Technical details on the fabrication of the ion source and the design of the ion gun will be discussed.

Kwan, Joe W.; Anderson, David; Chan, Chun Fai; Chupp, Warren W.; Eylon, Shmuel

1996-11-01

347

Pulsed-Power-Driven High Energy Density Physics and Inertial Confinement Fusion Research  

NASA Astrophysics Data System (ADS)

There continues to be dramatic progress in applying pulsed-power drivers to research in High Energy Density Physics (HEDP) and Inertial Confinement Fusion (ICF). The Z facility at Sandia National Laboratories delivers 20-MA load currents to create high magnetic fields (> 1000 T) and pressures (Mbar to Gbar). In a z-pinch configuration, the magnetic pressure (Lorentz Force) supersonically implodes a plasma created from a cylindrical wire array, which at stagnation generates a plasma with energy densities of 10 MJ/cm^3 and temperatures exceeding 1 keV at 0.1% of solid density. These HED plasmas produce x-ray energies approaching 2 MJ at powers greater than 200 TW for ICF, radiation hydrodynamics, radiation-material interactions, Inertial Fusion Energy, astrophysics, and opacity experiments. In an alternate configuration, the large magnetic pressure is used to directly drive Isentropic Compression Experiments (ICE) to pressures greater than 3 Mbar and accelerate flyer plates to 27 km/s for equation of state (EOS) experiments at pressures up to 10 Mbar in Al. The challenge to model these complex geometric configurations over multiple orders of magnitude in spatial scale, temperatures, densities, and radiation fluxes is daunting. Nevertheless, development of multi-dimensional radiation-MHD codes (e.g. ALEGRA) coupled with more accurate material models (e.g. quantum molecular dynamics calculations within density functional theory) has resulted in a productive synergy between validating the simulations and guiding the experiments. The Z facility is now routinely used to drive ICF capsules (focusing on implosion symmetry and neutron production) and several different HEDP experiments (including radiation-driven hydrodynamic jets; material EOS, phase transitions, and strength; and the detailed behavior of z-pinch wire array initiation and implosion). This research is performed in collaboration with many other groups from around the world. A $60M, five-year project to enhance the capability and precision of the Z facility will be completed in 2007 and will result in x-ray energies of nearly 3 MJ at powers over 300 TW. *Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy&;s National Nuclear Security Administration under contract No. DE-AC04-94AL85000.

Matzen, M. Keith

2004-11-01

348

Kinetic Alfven wave instability driven by electron temperature anisotropy in high-beta plasmas  

SciTech Connect

Based on the kinetic dispersion equation in the low-frequency condition of omegahigh-beta plasmas, which is associated with kinetic Alfven waves in the wave vector range of k{sub ||}lambda{sub I}<<1 and k{sub perpendicular}rho{sub i}<<1 (where lambda{sub I} and rho{sub i} are the ion inertial length and gyroradius, respectively), is investigated. The results show that the structures of both the growth rate and the real frequency are different from those driven by the ion temperature anisotropy. The growth rate is larger than that driven by the ion anisotropy. The critical instability condition is modified dramatically, in which the electron driven growth rate does not vanish at the classical critical point and its deviation from zero increases with the kinetic effect due to the short-wavelength modification.

Chen, L. [Purple Mountain Observatory, CAS, Nanjing 210008 (China)] [Graduate School, CAS, Beijing 100012 (China); Wu, D. J. [Purple Mountain Observatory, CAS, Nanjing 210008 (China)

2010-06-15

349

Decision fusion of very high resolution images for urban land-cover mapping based on Bayesian network  

NASA Astrophysics Data System (ADS)

Traditional image processing techniques have been proven to be inadequate for urban land-cover mapping using very high resolution (VHR) remotely sensed imagery. Abundant features such as texture, shape, and structural information can be extracted from high-resolution images, which make it possible to distinguish land covers more effectively. However, the multisource characteristics of VHR images place significant demands on the classification method in terms of both efficiency and effectiveness. The most often used method is vector stacking fusion, in which a single classifier is trained over the whole feature space; statistical differences and separability complementarities among different features are rarely considered. Hence, appropriate feature fusion and classification of multisource features become the key issues in the field of urban land-cover mapping. A novel decision fusion method based on a Bayesian network is proposed to handle the multisource features of VHR images which provide redundant or complementary results. Subclassifiers are constructed separately based on multiple feature sets and then embedded into the naive Bayesian network classifier (NBC). The final results are obtained by fusing all the subclassifiers into the NBC framework. Experiments on aerial and QuickBird images demonstrated that the performance of the proposed method is greatly improved compared with vector stacking methods, and significantly improved compared with the multiple-classifier systems and multiple kernels learning support vector machine. Moreover, the proposed method has advantages in feature fusion of VHR images in urban land-cover mapping.

Li, Qingquan; Tao, Jianbin; Hu, Qingwu; Liu, Pengcheng

2013-01-01

350

SIPHORE: Conceptual Study of a High Efficiency Neutral Beam Injector Based on Photo-detachment for Future Fusion Reactors  

Microsoft Academic Search

An innovative high efficiency neutral beam injector concept for future fusion reactors is under investigation (simulation and R&D) between several laboratories in France, the goal being to perform a feasibility study for the neutralization of intense high energy (1 MeV) negative ion (NI) beams by photo-detachment. The objective of the proposed project is to put together the expertise of three

A. Simonin; L. Christin; H. de Esch; P. Garibaldi; C. Grand; F. Villecroze; C. Blondel; C. Delsart; C. Drag; M. Vandevraye; A. Brillet; W. Chaibi

2011-01-01

351

A novel cell-free mitochondrial fusion assay amenable for high-throughput screenings of fusion modulators  

Microsoft Academic Search

BACKGROUND: Mitochondria are highly dynamic organelles whose morphology and position within the cell is tightly coupled to metabolic function. There is a limited list of essential proteins that regulate mitochondrial morphology and the mechanisms that govern mitochondrial dynamics are poorly understood. However, recent evidence indicates that the core machinery that governs mitochondrial dynamics is linked within complex intracellular signalling cascades,

Astrid C Schauss; Huiyan Huang; Seok-Yong Choi; Liqun Xu; Sébastien Soubeyrand; Patricia Bilodeau; Rodolfo Zunino; Peter Rippstein; Michael A Frohman; Heidi M McBride

2010-01-01

352

Aerosol Resuspension Model for MELCOR for Fusion and Very High Temperature Reactor Applications  

SciTech Connect

Dust is generated in fusion reactors from plasma erosion of plasma facing components within the reactor’s vacuum vessel (VV) during reactor operation. This dust collects in cooler regions on interior surfaces of the VV. Because this dust can be radioactive, toxic, and/or chemically reactive, it poses a safety concern, especially if mobilized by the process of resuspension during an accident and then transported as an aerosol though out the reactor confinement building, and possibly released to the environment. A computer code used at the Idaho National Laboratory (INL) to model aerosol transport for safety consequence analysis is the MELCOR code. A primary reason for selecting MELCOR for this application is its aerosol transport capabilities. The INL Fusion Safety Program (FSP) organization has made fusion specific modifications to MELCOR. Recent modifications include the implementation of aerosol resuspension models in MELCOR 1.8.5 for Fusion. This paper presents the resuspension models adopted and the initial benchmarking of these models.

B.J. Merrill

2011-01-01

353

Magnetized Target Fusion project with high density FRC at Los Alamos National Laboratory.  

SciTech Connect

We describe a program to demonstrate the scientific basis of Magnetized Target Fusion (MTF). MTF is a potentially low cost path to fusion which is intermediate in plasma regime between magnetic (MFE) and inertial fusion energy (IFE). MTF involves the compression of a magnetized target plasma and PdV heating to fusion relevant conditions inside a converging flux conserving boundary. We have chosen to demonstrate MTF by using a field-reversed configuration (FRC) as our magnetized target plasma and an imploding metal liner for compression. These choices take advantage of significant past scientific and technical accomplishments in MFE and Defense Programs research and should yield substantial plasma performance (n{tau}>10{sup 13}s-cm{sup -3}>5 keV) using an available pulsed-power implosion facility at modest cost. We have recently shown this FRC to be within a factor of 2-3 of required pressure and lifetime.

Intrator, T.; Park, J. Y.; Wurden, G. A.; Taccetti, J. M.; Tuszewski, M.; Zhang, S. Y.; Waganaar, W.; Furno, I.; Hsu, S.; Tejero, E.; Leonard, M.; Bass, C.; Grabowski, C.; Degnan, J. H.

2003-08-13

354

Compact reversed-field pinch reactor (CRFPR): a high-density approach to magnetic fusion energy  

Microsoft Academic Search

Because of the unique magnetic topology associated with the Reversed-Field Pinch (RFP), the compact reactor embodiment for this approach is particularly attractive from the viewpoint of low-field resistive coils operating with Ohmic losses that can be made small relative to the fusion power. The cost-optimized Compact RFP Reactor (CRFPR) design would operate with fusion-power-core power densities and mass utilizations that

R. L. Hagenson; R. A. Krakowski; R. N. Byrne; D. Dobrott

1982-01-01

355

Recent advances in high current vacuum arc ion sources for heavy ion fusion  

Microsoft Academic Search

For a heavy ion fusion induction linac driver, a source of heavy ions with charge states 1+–3+, ?0.5A current beams, ?20?s pulse widths and ?10Hz repetition rates is required. Thermionic sources have been the workhorse for the Heavy Ion Fusion (HIF) program to date, but suffer from heating problems for large areas and contamination. They are limited to low (contact)

Niansheng Qi; Jochen Schein; Rahul R. Prasad; Mahadevan Krishnan; Andre Anders; Joe Kwan; Ian Brown

2001-01-01

356

High frequency of beta thalassaemia in a small island population in Melanesia.  

PubMed Central

A study of the causes of anaemia in the south west Pacific archipelago of Vanuatu has identified one island, Maewo, where the carrier rate for beta thalassaemia exceeds 20%, one of the highest recorded incidences in the world. Homozygous beta thalassaemia is a major cause of infant mortality and a serious drain on health resources on this island. Interactions of beta thalassaemia with various forms of alpha + thalassaemia were common in this population. Coexistent alpha + thalassaemia leads to better haemoglobinised and larger red cells than are seen in simple beta thalassaemia heterozygotes and screening for the latter can only be reliably carried out by Hb A2 estimation.

Bowden, D K; Hill, A V; Weatherall, D J; Clegg, J B

1987-01-01

357

Progress towards a high-gain and robust target design for heavy ion fusion  

SciTech Connect

Recently [E. Henestroza et al., Phys. Plasmas 18, 032702 (2011)], a new inertial-fusion target configuration, the X-target, using one-sided axial illumination has been explored. This class of target uses annular and solid-profile heavy ion beams to compress and ignite deuterium-tritium (DT) fuel that fills the interior of metal cases that have side-view cross sections in the shape of an 'X.' X-targets using all-DT-filled metal cases imploded by three annular ion beams resulted in fuel densities of {approx}50 g/cm{sup 3} at peak compression, and fusion gains of {approx}50, comparable to heavy ion driven hohlraum targets [D. A. Callahan-Miller and M. Tabak, Phys. Plasmas 7, 2083 (2000)]. This paper discusses updated X-target configurations that incorporate inside the case a propellant (plastic) and a pusher (aluminum) surrounding the DT fuel. The updated configurations are capable of assembling higher fuel areal densities {approx}2 g/cm{sup 2} using two annular beams to implode the target to peak DT densities {approx}100 g/cm{sup 3}, followed by a fast-ignition solid ion beam which heats the high-density fuel to thermonuclear temperatures in {approx}200 ps to start the burn propagation, obtaining gains of {approx}300. These targets have been modeled using the radiation-hydrodynamics code HYDRA [M. M. Marinak et al., Phys. Plasmas 8, 2275 (2001)] in two- and three- dimensions to study the properties of the implosion as well as the ignition and burn propagation phases. At typical Eulerian mesh resolutions of a few microns, the aluminum-DT interface shows negligible Rayleigh-Taylor (RT) and Richtmyer-Meshkov instability growth; also, the shear flow of the DT fuel as it slides along the metal X-target walls, which drives the RT and Kelvin Helmholtz instabilities, does not have a major effect on the burning rate. An analytic estimate of the RT instability process at the Al-DT interface shows that the aluminum spikes generated during the pusher deceleration phase would not reach the ignition zone in time to affect the burning process. Also, preliminary HYDRA calculations, using a higher resolution mesh to study the shear flow of the DT fuel along the X-target walls, indicate that metal-mixed fuel produced near the walls would not be transferred to the DT ignition zone (at maximum {rho}R) located at the vertex of the X-target.

Henestroza, Enrique; Grant Logan, B. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2012-07-15

358

Mitigating Laser Imprint in Direct-Drive Inertial Confinement Fusion Implosions with High-Z Dopants  

NASA Astrophysics Data System (ADS)

Nonuniformities seeded by both long- and short-wavelength laser perturbations can grow via Rayleigh-Taylor (RT) instability in direct-drive inertial confinement fusion, leading to performance reduction in low-adiabat implosions. To mitigate the effect of laser imprinting on target performance, spherical RT experiments have been performed on OMEGA using Si- or Ge-doped plastic targets in a cone-in-shell configuration. Compared to a pure plastic target, radiation preheating from these high-Z dopants (Si/Ge) increases the ablation velocity and the standoff distance between the ablation front and laser-deposition region, thereby reducing both the imprinting efficiency and the RT growth rate. Experiments showed a factor of 2-3 reduction in the laser-imprinting efficiency and a reduced RT growth rate, leading to significant (3-5 times) reduction in the ?rms of shell ?R modulation for Si- or Ge-doped targets. These features are reproduced by radiation-hydrodynamics simulations using the two-dimensional hydrocode DRACO.

Hu, S. X.; Fiksel, G.; Goncharov, V. N.; Skupsky, S.; Meyerhofer, D. D.; Smalyuk, V. A.

2012-05-01

359

High Vapor Pressure Perfluorocarbons Cause Vesicle Fusion and Changes in Membrane Packing  

PubMed Central

Perfluorocarbons (PFCs) hold great promise for biomedical applications. However, relatively little is known about the impact of these chemicals on membranes. We used unilamellar vesicles to explore the effects of PFCs on membrane packing and vesicle stability. Four clinically relevant PFCs with varying vapor pressures (PP1, 294 mbar; PP2, 141 mbar; PP4, 9.6 mbar; and PP9, 2.9 mbar) were examined. Microscopy imaging and spectroscopic measurements suggest that PFCs, especially those with high vapor pressures, lead to vesicle fusion within hours. Upon exposure to PP1 and PP2 for 72 h, vesicles retained a spherical shape, but the size changed from ?200 nm to ?20–40 ?m. In addition, membrane packing underwent marked changes during this timeframe. A significant decrease in water content in the lipid polar headgroup regions occurred during the first 1–2-h exposure to PFCs, followed by a steady increase in water content over time. Possible mechanisms were proposed to explain these dramatic structural changes. The finding that chemically inert PFCs exhibited fusogenic activity and marked changes in membrane surface packing is novel, and should be considered when using PFCs for biomedical applications.

Venegas, Berenice; Wolfson, Marla R.; Cooke, Peter H.; Chong, Parkson Lee-Gau

2008-01-01

360

Thelytokous parthenogenesis in unmated queen honeybees (Apis mellifera capensis): central fusion and high recombination rates.  

PubMed

The subspecies of honeybee indigenous to the Cape region of South Africa, Apis mellifera capensis, is unique because a high proportion of unmated workers can lay eggs that develop into females via thelytokous parthenogenesis involving central fusion of meiotic products. This ability allows pseudoclonal lineages of workers to establish, which are presently widespread as reproductive parasites within the honeybee populations of South Africa. Successful long-term propagation of a parthenogen requires the maintenance of heterozygosity at the sex locus, which in honeybees must be heterozygous for the expression of female traits. Thus, in successful lineages of parasitic workers, recombination events are reduced by an order of magnitude relative to meiosis in queens of other honeybee subspecies. Here we show that in unmated A. m. capensis queens treated to induce oviposition, no such reduction in recombination occurs, indicating that thelytoky and reduced recombination are not controlled by the same gene. Our virgin queens were able to lay both arrhenotokous male-producing haploid eggs and thelytokous female-producing diploid eggs at the same time, with evidence that they have some voluntary control over which kind of egg was laid. If so, they are able to influence the kind of second-division meiosis that occurs in their eggs post partum. PMID:18716331

Oldroyd, Benjamin P; Allsopp, Michael H; Gloag, Rosalyn S; Lim, Julianne; Jordan, Lyndon A; Beekman, Madeleine

2008-08-20

361

Creating highly specific nucleases by fusion of active restriction endonucleases and catalytically inactive homing endonucleases  

PubMed Central

Zinc-finger nucleases and TALE nucleases are produced by combining a specific DNA-binding module and a non-specific DNA-cleavage module, resulting in nucleases able to cleave DNA at a unique sequence. Here a new approach for creating highly specific nucleases was pursued by fusing a catalytically inactive variant of the homing endonuclease I-SceI, as DNA binding-module, to the type IIP restriction enzyme PvuII, as cleavage module. The fusion enzymes were designed to recognize a composite site comprising the recognition site of PvuII flanked by the recognition site of I-SceI. In order to reduce activity on PvuII sites lacking the flanking I-SceI sites, the enzymes were optimized so that the binding of I-SceI to its sites positions PvuII for cleavage of the composite site. This was achieved by optimization of the linker and by introducing amino acid substitutions in PvuII which decrease its activity or disturb its dimer interface. The most specific variant showed a more than 1000-fold preference for the addressed composite site over an unaddressed PvuII site. These results indicate that using a specific restriction enzyme, such as PvuII, as cleavage module, offers an alternative to the otherwise often used catalytic domain of FokI, which by itself does not contribute to the specificity of the engineered nuclease.

Fonfara, Ines; Curth, Ute; Pingoud, Alfred; Wende, Wolfgang

2012-01-01

362

Development of superconductors for applications in high-field, high-current-density magnets for fusion research  

SciTech Connect

The development of large-bore, high-field magnets for fusion energy applications requires a system approach to both magnet and conductor design. At Lawrence Livermore National Laboratory (LLNL), the criteria used to choose superconductors include: strain tolerance, radiation tolerance, heat removal, stability, fabricability, and cost. We report on the performance of industrially produced, prototype, Ti-modified Nb/sub 3/Sn wires developed with LLNL support. Wire performance characteristics evaluated include critical current as a function of magnetic field, temperature, and applied strain. Tests were performed to determine how this performance translates to the performance of a cable-in-conduit conductor system using this wire. An alternative to Nb/sub 3/Sn superconductors is NbN, which is strain and radiation insensitive. We report preliminary efforts to produce multifilamentary NbN conductors by liquid-metal infiltration of NbN-coated, high-strength fibers. In addition, we discuss the fabrication of multifilamentary NbN conductors and their possible impact on magnet design.

Summers, L.T.; Miller, J.R.

1986-09-26

363

Pulsed-power-driven high energy density physics and inertial confinement fusion research  

SciTech Connect

The Z accelerator [R. B. Spielman, W. A. Stygar, J. F. Seamen et al., Proceedings of the 11th International Pulsed Power Conference, Baltimore, MD, 1997, edited by G. Cooperstein and I. Vitkovitsky (IEEE, Piscataway, NJ, 1997), Vol. 1, p. 709] at Sandia National Laboratories delivers {approx}20 MA load currents to create high magnetic fields (>1000 T) and high pressures (megabar to gigabar). In a z-pinch configuration, the magnetic pressure (the Lorentz force) supersonically implodes a plasma created from a cylindrical wire array, which at stagnation typically generates a plasma with energy densities of about 10 MJ/cm{sup 3} and temperatures >1 keV at 0.1% of solid density. These plasmas produce x-ray energies approaching 2 MJ at powers >200 TW for inertial confinement fusion (ICF) and high energy density physics (HEDP) experiments. In an alternative configuration, the large magnetic pressure directly drives isentropic compression experiments to pressures >3 Mbar and accelerates flyer plates to >30 km/s for equation of state (EOS) experiments at pressures up to 10 Mbar in aluminum. Development of multidimensional radiation-magnetohydrodynamic codes, coupled with more accurate material models (e.g., quantum molecular dynamics calculations with density functional theory), has produced synergy between validating the simulations and guiding the experiments. Z is now routinely used to drive ICF capsule implosions (focusing on implosion symmetry and neutron production) and to perform HEDP experiments (including radiation-driven hydrodynamic jets, EOS, phase transitions, strength of materials, and detailed behavior of z-pinch wire-array initiation and implosion). This research is performed in collaboration with many other groups from around the world. A five year project to enhance the capability and precision of Z, to be completed in 2007, will result in x-ray energies of nearly 3 MJ at x-ray powers >300 TW.

Matzen, M. Keith; Sweeney, M.A.; Adams, R.G.; Asay, J.R.; Bailey, J.E.; Bennett, G.R.; Bliss, D.E.; Bloomquist, D.D.; Brunner, T.A.; Campbell, R.B.; Chandler, G.A.; Coverdale, C.A.; Cuneo, M.E.; Davis, J.-P.; Deeney, C.; Desjarlais, M.P.; Donovan, G.L.; Garasi, C.J.; Haill, T.A.; Hall, C.A. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1191 (United States)] (and others)

2005-05-15

364

Distinctive features of collisionless gradient drift instabilities in a high-{beta} plasma in a highly nonuniform magnetic field  

SciTech Connect

A set of Vlasov-Maxwell equations for collisionless electromagnetic drift instabilities of high-{beta} plasma configurations with a nonuniform magnetic fields is solved. The effect of the transverse static magnetic field variation and magnetic field line curvature, as well as the plasma temperature and density gradients, is considered. It is shown that, in a nonuniform magnetic field, the behavior of the instabilities differs substantially from that in a uniform field. Electromagnetic modes propagating strictly transverse to the lines of the static magnetic field are analyzed in detail, and unstable solutions are obtained for both extraordinary and ordinary waves. Numerical results show that, in the latter case, instability occurs when the magnetic field decreases toward the periphery and the plasma temperature and density gradients are oppositely directed.

Chirkov, A. Yu.; Khvesyuk, V. I. [Bauman Moscow State Technical University (Russian Federation)

2011-05-15

365

Investigation into the dissolution and direct assay of high-fired plutonium dioxide. [Fusion-melt with potassium pyrosulfate and sodium peroxide  

Microsoft Academic Search

A fusion-melt and dissolution assay method has been developed and tested for the quantitative analysis of high-fired plutonium dioxide. The method employs fusion of the plutonium dioxide at temperatures greater than the melting point of an eutectic mixture of potassium pyrosulfate plus sodium peroxide. The resultant melt is then titrated directly by either controlled potential coulometry or a gravimetric titration,

1976-01-01

366

High-Precision Half-Life Measurement for the Superallowed {beta}{sup +} Emitter {sup 26}Al{sup m}  

SciTech Connect

A high-precision half-life measurement for the superallowed {beta}{sup +} emitter {sup 26}Al{sup m} was performed at the TRIUMF-ISAC radioactive ion beam facility yielding T{sub 1/2}=6346.54{+-}0.46{sub stat{+-}}0.60{sub syst} ms, consistent with, but 2.5 times more precise than, the previous world average. The {sup 26}Al{sup m} half-life and ft value, 3037.53(61) s, are now the most precisely determined for any superallowed {beta} decay. Combined with recent theoretical corrections for isospin-symmetry-breaking and radiative effects, the corrected Ft value for {sup 26}Al{sup m}, 3073.0(12) s, sets a new benchmark for the high-precision superallowed Fermi {beta}-decay studies used to test the conserved vector current hypothesis and determine the V{sub ud} element of the Cabibbo-Kobayashi-Maskawa quark mixing matrix.

Finlay, P.; Svensson, C. E.; Green, K. L.; Leach, K. G.; Phillips, A. A.; Sumithrarachchi, C. S. [Department of Physics, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada); Ettenauer, S. [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, V6T 2A3 (Canada); Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, V6T 1Z4 (Canada); Ball, G. C.; Bandyopadhyay, D.; Djongolov, M.; Hackman, G.; Pearson, C. J.; Williams, S. J [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, V6T 2A3 (Canada); Leslie, J. R. [Department of Physics, Queen's University, Kingston, Ontario, K7L 3N6 (Canada); Andreoiu, C.; Cross, D. S. [Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, V5A 1S6 (Canada); Austin, R. A. E. [Astronomy and Physics Department, Saint Mary's University, Halifax, Nova Scotia, B3H 3C3 (Canada); Demand, G. [Department of Physics, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada); Department of Physics, Queen's University, Kingston, Ontario, K7L 3N6 (Canada); Garrett, P. E.; Triambak, S. [Department of Physics, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada); TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, V6T 2A3 (Canada)

2011-01-21

367

Fast magnetization of a high-to-low-beta plasma beam  

SciTech Connect

The magnetization of a high-beta (plasma energy density/magnetic field energy density{equivalent to}{beta}{ge}1) hydrogen-plasma beam injected into a vacuum transverse magnetic field is studied experimentally. Nominal parameters were {ital T}{sub {ital i}}{approx}1 eV, {ital T}{sub {ital e}}{approx}5 eV, {ital n}{le}3{times}10{sup 13} cm{sup {minus}3}, {ital v}{sub {ital i}}{le}7{times}10{sup 6} cm/sec, {ital t}{sub pulse}{lt}70 {mu}sec, {ital B}{sub {ital z}}{le}300 G. Plasma characteristics were measured for a wide beam, {ital a}/{rho}{sub {ital i}}{le}35, and a downstream distance, {ital x}{le}300{rho}{sub {ital i}}, where {ital a} is the beam radius, {ital x} is the downstream distance, and {rho}{sub {ital i}} is the ion gyroradius. A brief initial state of diamagnetic propagation is observed, followed by {bold E}{times}{bold B} (magnetized) propagation; {bold E}{times}{bold B} propagation is accompanied by beam compression transverse to {bold B} with as much as a factor of 4 increase in density and a slight drift of the beam in the ion Lorentz force direction. For {ital B}{sub {ital z}}=200--300 G the observed magnetization time is much faster than calculated from classical Spitzer conductivity and is more of the order of the magnetization time based on Hall conductivity.

Song, J.J.; Wessel, F.J.; Yur, G.; Rahman, H.U.; Rostoker, N.; White, R.S. (Department of Physics, University of California, Irvine, CA (USA))

1990-10-01

368

High-level aminoglycoside resistance and beta-lactamase production in enterococci at a tertiary care hospital in India.  

PubMed

Enterococci, a family of important opportunistic pathogens, exhibits intrinsic resistance to a number of antimicrobial agents in addition to acquired multidrug resistance. The present study was conducted to determine whether enterococci at a tertiary care hospital in India exhibit high-level aminoglycoside resistance and beta-lactamase production. Enterococci were isolated from various clinical specimens and identified phenotypically. High-level resistance (HLR) to gentamicin, kanamycin, and streptomycin was determined by disc diffusion tests. Beta-lactamase production was detected using three methods: iodometric, acidometric, and chromogenic beta-lactamase assays. Among the 86 enterococci isolated, 34 were found to have HLR to one or more aminoglycosides; HLR to kanamycin was most common. Vancomycin resistance was present in four of the isolates. Only one enterococcus produced beta-lactamase, and it was sensitive to ampicillin on routine disc diffusion testing. Beta-lactamase production among enterococci, though not very common, may be missed on routine susceptibility testing. Frequent occurrence of HLR to kanamycin makes amikacin a poor choice for inclusion in combination therapy with cell wall-active agents. PMID:19305061

Agarwal, Jyotsna; Kalyan, Rajkumar; Singh, Mastan

2009-03-01

369

A NATIONAL COLLABORATORY TO ADVANCE THE SCIENCE OF HIGH TEMPERATURE PLASMA PHYSICS FOR MAGNETIC FUSION  

SciTech Connect

This report summarizes the work of the University of Utah, which was a member of the National Fusion Collaboratory (NFC) Project funded by the United States Department of Energy (DOE) under the Scientific Discovery through Advanced Computing Program (SciDAC) to develop a persistent infrastructure to enable scientific collaboration for magnetic fusion research. A five year project that was initiated in 2001, it the NFC built on the past collaborative work performed within the U.S. fusion community and added the component of computer science research done with the USDOE Office of Science, Office of Advanced Scientific Computer Research. The project was itself a collaboration, itself uniting fusion scientists from General Atomics, MIT, and PPPL and computer scientists from ANL, LBNL, and Princeton University, and the University of Utah to form a coordinated team. The group leveraged existing computer science technology where possible and extended or created new capabilities where required. The complete finial report is attached as an addendum. The In the collaboration, the primary technical responsibility of the University of Utah in the collaboration was to develop and deploy an advanced scientific visualization service. To achieve this goal, the SCIRun Problem Solving Environment (PSE) is used on FusionGrid for an advanced scientific visualization service. SCIRun is open source software that gives the user the ability to create complex 3D visualizations and 2D graphics. This capability allows for the exploration of complex simulation results and the comparison of simulation and experimental data. SCIRun on FusionGrid gives the scientist a no-license-cost visualization capability that rivals present day commercial visualization packages. To accelerate the usage of SCIRun within the fusion community, a stand-alone application built on top of SCIRun was developed and deployed. This application, FusionViewer, allows users who are unfamiliar with SCIRun to quickly create visualizations and perform analysis of their simulation data from either the MDSplus data storage environment or from locally stored HDF5 files. More advanced tools for visualization and analysis also were created in collaboration with the SciDAC Center for Extended MHD Modeling. Versions of SCIRun with the FusionViewer have been made available to fusion scientists on the Mac OS X, Linux, and other Unix based platforms and have been downloaded 1163 times. SCIRun has been used with NIMROD, M3D, BOUT fusion simulation data as well as simulation data from other SciDAC application areas (e.g., Astrophysics). The subsequent visualization results - including animations - have been incorporated into invited talks at multiple APS/DPP meetings as well as peer reviewed journal articles. As an example, SCIRun was used for the visualization and analysis of a NIMROD simulation of a disruption that occurred in a DIII-D experiment. The resulting animations and stills were presented as part of invited talks at APS/DPP meetings and the SC04 conference in addition to being highlighted in the NIH/NSF Visualization Research Challenges Report. By achieving its technical goals, the University of Utah played a key role in the successful development of a persistent infrastructure to enable scientific collaboration for magnetic fusion research. Many of the visualization tools developed as part of the NFC continue to be used by Fusion and other SciDAC application scientists and are currently being supported and expanded through follow-on up on SciDAC projects (Visualization and Analytics Center for Enabling Technology, and the Visualization and Analysis in Support of Fusion SAP).

Allen R. Sanderson; Christopher R. Johnson

2006-08-01

370

Preliminary analysis of alpha-particle effects in the fusion ignition experiment ignitex  

SciTech Connect

In this paper a simple fusion experiment for the production and control do deuterium-tritium-ignited plasmas for scientific study is considered. The basic elements of fusion product alpha-particle containment is rather high even with the assumption of significant levels of toroidal asymmetries. Production of thermally stable plasmas is possible because of the low-beta thermal damping provided by electron cyclotron emission. The stability of internal kink modes, high-number ballooning modes, and toroidicity-induced shear Alfven eigen-modes is investigated in the presence of fusion alpha particles. These modes can be either stable or unstable depending on the selected operational regime at ignition.

Carrera, R.; Montalvo, E. (Texas Univ., Austin, TX (United States)); Fu, G.Y. (CRPP, Lausanne (CH)); Miley, G.H. (Illinois Univ., Urbana, IL (United States)); Hively, L.M. (Oak Ridge National Lab., TN (United States)); Rosenbluth, M.N. (California Univ., San Diego, CA (United States)); Tamor, S. (La Jolla Inst., Arlington, VA (United States))

1990-12-01

371

MHD stability in high. beta. /sub /Tau// DIII-D divertor discharges  

SciTech Connect

Doublet III-D has achieved a ..beta../sub /Tau// of over 6% in H-mode divertor plasmas and has not exceeded the beta limit as allowed by ideal MHD instabilities. Experimental results of this test run are summarized. 4 refs., 4 figs. (DWL)

Lao, L.L.; Strait, E.J.; Taylor, T.S.; Chu, M.S.; Burrell, K.H.; DeBoo, J.C.; Gohil, P.; Groebner, R.J.; Hsieh, C.L.; Howl, W.; Kellman, A.G.; Osborne, T.H.; Ozeki, T.; Stambaugh, R.D.; St. John, H.; Turnbull, A.D.

1988-03-01

372

A High Temperature Electrochemical Energy Storage System Based on Sodium Beta-Alumina Solid Electrolyte (Base)  

Microsoft Academic Search

This report summarizes the work done during the period September 1, 2005 and March 31, 2008. Work was conducted in the following areas: (1) Fabrication of sodium beta alumina solid electrolyte (BASE) using a vapor phase process. (2) Mechanistic studies on the conversion of -alumina + zirconia into beta-alumina + zirconia by the vapor phase process. (3) Characterization of BASE

Anil Virkar

2008-01-01

373

Activities on heavy ion inertial fusion and beam-driven high energy density science in Japan  

NASA Astrophysics Data System (ADS)

Recent research activities in Japan relevant to heavy ion fusion (HIF) are presented. During the past two years, significant progress in HIF and high energy density (HED) physics research has been made by a number of research groups in universities and accelerator facilities. Evolutions in phase space during the longitudinal compression of intense beams were investigated at UU-NUT-TIT. Beam-plasma interaction experiments and related theoretical studies are in progress at RLNR-TIT. In the study, shock-heated hydrogen was used for the interaction experiments as a well-defined non-ideal-plasma target. In the beam-plasma interaction experiments, a special emphasis is placed on an evaluation of non-linear effects on the stopping power in a beam-heated plasma target. A direct-indirect hybrid scheme of a beam-driven ICF target has been proposed and discussed at UU. In the same group, a method for controlling the Rayleigh-Taylor instability in imploding fuel target has been proposed using oscillating heavy ion beams (HIBs). Core dynamics of the impact ignition has been investigated both experimentally and numerically at ILE—Osaka. Dense plasmas driven by intense ion beams and/or a pulse powered device, were evaluated by a group of DES-TIT, concerning the researches on HED and warm dense matter (WDM) physics. A quasi-statically tamped target was proposed to make a well-defined, warm dense state for equation-of-state (EOS) studies based on ion accelerators. The potentiality of the new facility planned at KEK was evaluated by a collaborating group of TIT-UU-KEK, which can extend the parameter regime for laboratory experiments to study the properties of matter under extreme conditions. A possible method to make a high-pressure condition for study of the planetary science was discussed as a short-term subject of intense HIBs.

Horioka, K.; Kawamura, T.; Nakajima, M.; Kondo, K.; Ogawa, M.; Oguri, Y.; Hasegawa, J.; Kawata, S.; Kikuchi, T.; Sasaki, T.; Murakami, M.; Takayama, K.

2009-07-01

374

High efficiency beta-decay spectroscopy using a planar germanium double-sided strip detector  

NASA Astrophysics Data System (ADS)

Beta-decay spectroscopy experiments are limited by the detection efficiency of ions and electrons in the experimental setup. While there is a variety of different experimental setups in use for beta-decay spectroscopy, one popular choice is silicon double-sided strip detectors (DSSD). The higher Z of Ge and greater availability of thicker detectors as compared to Si potentially offer dramatic increases in the detection efficiency for beta-decay electrons. In this work, a planar GeDSSD has been commissioned for use in beta-decay spectroscopy experiments at the National Superconducting Cyclotron Laboratory (NSCL). The implantation response of the detector and its beta-decay detection efficiency is discussed.

Larson, N.; Liddick, S. N.; Bennett, M.; Bowe, A.; Chemey, A.; Prokop, C.; Simon, A.; Spyrou, A.; Suchyta, S.; Quinn, S. J.; Tabor, S. L.; Tai, P. L.; Tripathi, Vandana; VonMoss, J. M.

2013-11-01

375

Impaired activation of adenylyl cyclase in lung of the Basenji-greyhound model of airway hyperresponsiveness: decreased numbers of high affinity beta-adrenoceptors.  

PubMed Central

1. To evaluate mechanisms involved in the impaired beta-adrenoceptor stimulation of adenylyl cyclase in tissues from the Basenji-greyhound (BG) dog model of airway hyperresponsiveness, we compared agonist and antagonist binding affinity of beta-adrenoceptors, beta-adrenoceptor subtypes, percentage of beta-adrenoceptors sequestered, and coupling of the beta-adrenoceptor to Gs alpha in lung membranes from BG and control mongrel dogs. We found that lung membranes from the BG dog had higher total numbers of beta-adrenoceptors with a greater percentage of receptors of the beta 2 subtype as compared to mongrel lung membranes. 2. Agonist and antagonist binding affinity and the percentage of beta-adrenoceptors sequestered were not different in BG and mongrel dog lung membranes. However, the percentage of beta-adrenoceptors in the high affinity state for agonist was decreased in BG lung membranes suggesting an uncoupling of the receptor from Gs alpha. 3. Impaired coupling between the beta-adrenoceptor and G protein documented by the decreased numbers of beta-adrenoceptors in the high affinity state in BG lung membranes, is a plausible explanation for the reduced stimulation of adenylyl cyclase and the resultant reduction in airway smooth muscle relaxation in this model.

Emala, C. W.; Aryana, A.; Hirshman, C. A.

1996-01-01

376

Yttrium-90 -- current status, expected availability and applications of a high beta energy emitter.  

PubMed

Yttrium-90 ((90)Y, T(1/2) 64.14 h) is a key example of a high beta energy-emitting radionuclide which is available from the strontium-90 ((90)Sr)/(90)Y radionuclide generator system. Clinical uses of (90)Y-labeled radiopharmaceutical agents have been pursued for many years and many applications have proven to be clinical effective. These most notably include the application of 90Y-labeled antibodies for a variety of applications such as for effective treatment of non-Hodgkin's lymphoma. One of the major advantages for use of (90)Y is ready availability from the very long-lived (90)Sr parent (T(1/2) 28.78 y). Because of the importance of maintaining generator performance and minimizing parent breakthrough, this paper describes development, use and quality control of both high capacity cation adsorption-type and electrochemical generator systems. In addition, the preparation and targeting to tumors in mice of DOTA-conjugated Nimotuzamab (h-R3) antibody which recognizes the external domain of the EPFR antibody radiolabeled with (90)Y obtained from the electrochemical generator is also described. As a key example for clinical applications of (90)Y, the use of (90)Y-labeled biotin for intra-operative pre-targeting for radionuclide therapy (IART®) of breast cancer is also described. PMID:22697484

Montaña, R Leyva; González, I Hernández; Ramirez, A Alberti; Garaboldi, L; Chinol, M

2012-07-01

377

Extending high-beta operation in NSTX through plasma shaping and early H-mode transitions  

NASA Astrophysics Data System (ADS)

The National Spherical Torus Experiment (NSTX) resumed operation in February 2004 and completed in July a program of experiments which expanded its operating space and contributed to resolving issues both for the design of future ST devices and in toroidal magnetic confinement physics. Improvements in plasma control have led to the achievement of higher plasma elongation, ? = 2.6 and normalized current, IN = I_p/aBT = 6.9 MA/m \\cdot T. By optimizing the current ramp-up, gas puffing and neutral beam power waveforms, reliable early transitions to the H-mode have been obtained, which improved confinement and broadened the pressure profiles, permitting the achievement of very high beta, ?T = 34%, determined by EFIT from external magnetic and kinetic profile data and corroborated by analysis with TRANSP. These improvements have led to the achievement of 1MA pulses with 1s duration that were not limited by the available transformer flux. First measurements have also been obtained with the MSE diagnostic. The features of the NSTX operating space and characteristics of the high-? plasmas will be discussed. This work supported by DOE Contract Number DE-AC02-76CH03073

Gates, D. A.; Menard, J. E.; Maingi, R.; Wade, M.

2004-11-01

378

Structural properties of 1050 MHz, beta = 0.49 single cell elliptical cavity for high current proton acceleration  

Microsoft Academic Search

A single cell 1050 MHz, beta = 0.49 elliptical cavity has been designed for possible use in High Current Proton Accelerator. The structural behavior of the single cell superconducting elliptical cavity has been studied by finite element structural analysis code. The max. Von MISES stress and cavity wall displacements were calculated under the vacuum load for various wall thickness. Both

Amitava Roy; K. C. Mittal

2008-01-01

379

Highly efficient conjugate reduction of alpha,beta-unsaturated nitriles catalyzed by copper/xanthene-type bisphosphine complexes.  

PubMed

Alpha,beta-unsaturated nitriles are chemoselectively reduced to the corresponding saturated nitriles in high yields using a copper-DPEphos or Xantphos complex as catalyst in the presence of polymethylhydrosiloxane (PMHS) as the stoichiometric reducing agent and t-butanol as additive. PMID:15791322

Kim, Daesung; Park, Bu-Mahn; Yun, Jaesook

2005-02-07

380

High beta tokamak research and plasma theory. Report of progress, 8 November 1989-1 November 1990.  

National Technical Information Service (NTIS)

Our activities on High Beta Tokamak Research during the past 12 months of the present budget period can be divided into four areas: completion of kink mode studies in HBT; completion of carbon impurity transport studies in HBT; design of HBT-EP; and const...

1990-01-01

381

Isolation of Enterobacter aerogenes susceptible to beta-lactam antibiotics despite high level beta-lactamase production  

Microsoft Academic Search

This report describes a patient with nosocomial meningitis from whom four distinct isolates ofEnterobacter aerogenes were recovered over a complicated course of chemotherapy. The initial isolate was susceptible to expanded spectrum ?-lactams despite constitutive production of high levels of ?-lactamase. Resistant isolates recovered during antibiotic therapy had lost a 42,000 outer membrane protein. These data suggest that b-lactam susceptibility in

M. A. Mellencamp; J. S. Roccaforte; L. C. Preheim; C. C. Sanders; C. A. Anene; M. J. Bittner

1990-01-01

382

High divergence in primate-specific duplicated regions: Human and chimpanzee Chorionic Gonadotropin Beta genes  

PubMed Central

Background Low nucleotide divergence between human and chimpanzee does not sufficiently explain the species-specific morphological, physiological and behavioral traits. As gene duplication is a major prerequisite for the emergence of new genes and novel biological processes, comparative studies of human and chimpanzee duplicated genes may assist in understanding the mechanisms behind primate evolution. We addressed the divergence between human and chimpanzee duplicated genomic regions by using Luteinizing Hormone Beta (LHB)/Chorionic Gonadotropin Beta (CGB) gene cluster as a model. The placental CGB genes that are essential for implantation have evolved from an ancestral pituitary LHB gene by duplications in the primate lineage. Results We shotgun sequenced and compared the human (45,165 bp) and chimpanzee (39,876 bp) LHB/CGB regions and hereby present evidence for structural variation resulting in discordant number of CGB genes (6 in human, 5 in chimpanzee). The scenario of species-specific parallel duplications was supported (i) as the most parsimonious solution requiring the least rearrangement events to explain the interspecies structural differences; (ii) by the phylogenetic trees constructed with fragments of intergenic regions; (iii) by the sequence similarity calculations. Across the orthologous regions of LHB/CGB cluster, substitutions and indels contributed approximately equally to the interspecies divergence and the distribution of nucleotide identity was correlated with the regional repeat content. Intraspecies gene conversion may have shaped the LHB/CGB gene cluster. The substitution divergence (1.8–2.59%) exceeded two-three fold the estimates for single-copy loci and the fraction of transversional mutations was increased compared to the unique sequences (43% versus ~30%). Despite the high sequence identity among LHB/CGB genes, there are signs of functional differentiation among the gene copies. Estimates for dn/ds rate ratio suggested a purifying selection on LHB and CGB8, and a positive evolution of CGB1. Conclusion If generalized, our data suggests that in addition to species-specific deletions and duplications, parallel duplication events may have contributed to genetic differences separating humans from their closest relatives. Compared to unique genomic segments, duplicated regions are characterized by high divergence promoted by intraspecies gene conversion and species-specific chromosomal rearrangements, including the alterations in gene copy number.

2008-01-01

383

Zr-zeolite beta: a new heterogeneous catalyst system for the highly selective cascade transformation of citral to (+/-)-menthol.  

PubMed

The transformation of citral to menthols involves hydrogenation steps as well as cyclisation of the intermediate, citronellal. The ability of Zr-zeolite beta to catalyse the cyclisation with high diastereoselectivity to (+/-)-isopulegol is the critical step in this cascade transformation. Bifunctional catalysts containing nickel or rhodium supported on Zr-zeolite beta gave menthols in yields of 87-89% and an excellent diastereoselectivity of 94% for the desired (+/-)-menthol. Dual catalyst systems of Zr-zeolite beta and nano-dispersed Ni on an MCM-41 support were equally effective and have the added advantage that the rates of the acid- and hydrogenation-catalysed steps can be independently varied. By applying a pressure ramp of 0.2-2 MPa, the yield of menthols could be increased to 95%, with 94% diastereoselectivity for (+/-)-menthol. The low initial pressure minimises the rates of competing hydrogenation reactions to byproducts such as citronellol and 3,7-dimethyloctanol. PMID:19132702

Nie, Yuntong; Jaenicke, Stephan; Chuah, Gaik-Khuan

2009-01-01

384

Relative contributions of fusion and fragmentation mechanisms in J/{psi} photoproduction at high energy  

SciTech Connect

We study J/{psi} photoproduction via the fusion and fragmentation mechanisms at the HERA Collider within the frameworks of the collinear parton model and the quasi-multi-Regge kinematics approach using the factorization formalism of nonrelativistic QCD at leading order in the strong coupling constant {alpha}{sub s} and the relative velocity v of the bound quarks. It is shown that the fusion production mechanism dominates over the fragmentation production mechanism at the all relevant J/{psi} transverse momenta. The J/{psi} meson p{sub T} spectra in the fragmentation and fusion production at the asymptotilally large p{sub T} have equal slopes in the quasi-multi-Regge kinematics approach, opposite the collinear parton model.

Saleev, V. A.; Shipilova, A. V. [II. Institut fuer Theoretische Physik, Universitaet Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany); Department of Physics, Samara State University, Ac. Pavlov St. 1, 443011 Samara (Russian Federation)

2007-02-01

385

Fusion neutron irradiation of Ni(Si) alloys at high temperature  

SciTech Connect

Two Ni-4% Si alloys, with different cold work levels, are irradiated with 14 MeV fusion neutrons at 623 K, and their Curie temperatures are monitored during irradiation. The results are compared to those of an identical alloy irradiated by 2 MeV electrons. The results show that increasing dislocation density increases the Curie temperature change rate. At the same damage rate, the Curie temperature change rate for the alloy irradiated by 14 MeV fusion neutrons is only 6 to 7% of that for an identical alloy irradiated by 2 MeV electrons. It is well known that the migration of radiation induced defects contributes to segregation of silicon atoms at sinks in this alloy, causing the Curie temperature changes. The current results imply that the relative free defect production efficiency decreases from one for the electron irradiated sample to 6 to 7% for the fusion neutron irradiated sample. 17 refs., 4 figs., 1 tab.

Huang, J.S.; Guinan, M.W.; Hahn, P.A.

1987-09-01

386

High heat flux issues for plasma-facing components in fusion reactors  

NASA Astrophysics Data System (ADS)

Plasma facing components in tokamak fusion reactors are faced with a number of difficult high heat flux issues. These components include: first wall armor tiles, pumped limiters, diverter plates, rf antennae structure, and diagnostic probes. Peak heat fluxes are 15 - 30 MW/m2 for diverter plates, which will operate for 100 - 1000 seconds in future tokamaks. Disruption heat fluxes can approach 100,000 MW/m2 for 0.1 ms. Diverter plates are water-cooled heat sinks with armor tiles brazed on to the plasma facing side. Heat sink materials include OFHC, GlidcopTM, TZM, Mo-41Re, and niobium alloys. Armor tile materials include: carbon fiber composites, beryllium, silicon carbide, tungsten, and molybdenum. Tile thickness range from 2 - 10 mm, and heat sinks are 1 - 3 mm. A twisted tape insert is used to enhance heat transfer and increase the burnout safety margin from critical heat flux limits to 50 - 60 MW/m2 with water at 10 m/s and 4 MPa. Tests using rastered electron beams have shown thermal fatigue failures from cracks at the brazed interface between tiles and the heat sink after only 1000 cycles at 10 - 15 MW/m2. These fatigue lifetimes need to be increased an order of magnitude to meet future requirements. Other critical issues for plasma facing components include: surface erosion from sputtering and disruption erosion, eddy current forces and runaway electron impact from disruptions, neutron damage, tritium retention and release, remote maintenance of radioactive components, corrosion-erosion, and loss-of-coolant accidents.

Watson, Robert D.

1993-02-01

387

Identification of the B1 and B2 subunits of human placental laminin and rat parietal-yolk-sac laminin using antisera specific for murine laminin-beta-galactosidase fusion proteins.  

PubMed Central

Antisera raised against fusion proteins consisting of murine laminin B1 and B2 subunit sequences fused to the C-terminus of Escherichia coli beta-galactosidase were tested for their subunit specificity on Western blots of deglycosylated murine Engelbreth-Holm-Swarm (EHS) laminin. The antisera raised against B2 subunit sequences (anti-XLB2.1 and anti-XLB2.2) bound only to the EHS laminin B2 subunit. One of the antisera raised against B1 subunit sequences (anti-XLB1.2) was specific for the B1 subunit, whereas two others (anti-XLB1.1 and anti-XLB1.3) cross-reacted with the EHS laminin B2 subunit. Gold-labelled heparin-albumin was shown to bind specifically to the A subunit of deglycosylated EHS laminin on Western blots. These reagents were used to identify the homologous subunits in rat parietal-yolk-sac laminin and human placental laminin. The anti-(fusion protein) antisera identified the B1 and B2 subunits of the rat laminin, and these were similar in size to the murine EHS B subunits. Human placental laminin gave bands of 400, 340, 230, 190 and 180 kDa on reducing SDS/PAGE. The anti-(fusion protein) antisera identified the 230 and 190 kDa bands as the B1 and B2 subunits respectively. Gold-labelled heparin-albumin bound to the 400, 340 and 190 kDa bands of human placental laminin and so did not unambiguously identify a single A subunit. The human placental laminin may contain a mixture of isoforms, with alternative subunits substituting for the A subunit. Images Fig. 2. Fig. 3. Fig. 4. Fig. 5. Fig. 6.

Brown, J C; Spragg, J H; Wheeler, G N; Taylor, P W

1990-01-01

388

Virtual screening against highly charged active sites: identifying substrates of alpha-beta barrel enzymes.  

PubMed

We have developed a virtual ligand screening method designed to help assign enzymatic function for alpha-beta barrel proteins. We dock a library of approximately 19,000 known metabolites against the active site and attempt to identify the relevant substrate based on predicted relative binding free energies. These energies are computed using a physics-based energy function based on an all-atom force field (OPLS-AA) and a generalized Born implicit solvent model. We evaluate the ability of this method to identify the known substrates of several members of the enolase superfamily of enzymes, including both holo and apo structures (11 total). The active sites of these enzymes contain numerous charged groups (lysines, carboxylates, histidines, and one or more metal ions) and thus provide a challenge for most docking scoring functions, which treat electrostatics and solvation in a highly approximate manner. Using the physics-based scoring procedure, the known substrate is ranked within the top 6% of the database in all cases, and in 8 of 11 cases, it is ranked within the top 1%. Moreover, the top-ranked ligands are strongly enriched in compounds with high chemical similarity to the substrate (e.g., different substitution patterns on a similar scaffold). These results suggest that our method can be used, in conjunction with other information including genomic context and known metabolic pathways, to suggest possible substrates or classes of substrates for experimental testing. More broadly, the physics-based scoring method performs well on highly charged binding sites and is likely to be useful in inhibitor docking against polar binding sites as well. The method is fast (<1 min per ligand), due largely to an efficient minimization algorithm based on the truncated Newton method, and thus, it can be applied to thousands of ligands within a few hours on a small Linux cluster. PMID:15697231

Kalyanaraman, Chakrapani; Bernacki, Katarzyna; Jacobson, Matthew P

2005-02-15

389

q Profile evolution and enhanced core confinement of high {beta}{sub p} plasmas in DIII-D  

SciTech Connect

In DIII-D the authors have investigated the long pulse evolution of high poloidal beta ({sub beta}{sub p}), double-null diverted H-mode discharges, which exhibit high bootstrap current fractions attractive for a reactor. At low currents I{sub p}, the current profile evolved over several seconds and the on-axis safety factor (q{sub 0}) increased. When q{sub 0} increased above {approximately}2, the MHD character changed from an m/n = 2/1 to an m/n = 3/1 internal kink mode, where m(n) are poloidal (toroidal) mode numbers, which then disappeared with further increases in q{sub 0}. Coincident with a strong reduction of fluctuations, the authors observed enhanced core confinement, leading to strong density peaking, a further rise in {beta}{sub p}, and a bootstrap current increasing to I{sub boot}/I{sub p} {approx} 0.8, peaked within the core. Ideal MHD calculations showed access to second stability during the density rise. During the enhanced performance phase core particle lifetime ({tau}{sub p}) and global energy lifetime ({tau}{sub E}) increased by factors of 2 and 1.2 respectively. Transport analysis showed that core particle and thermal diffusivities D{sub e} and {chi}{sub eff} approached neoclassical values. During the low current experiments, large losses of fast ions (typically {approximately}50% at 0.4 MA) were observed; at higher currents these losses are much smaller. The authors have also investigated discharges with current rampdown to high {beta}{sub p}. For a 5 to 6 {tau}{sub E} duration following rampdown, enhanced values of {beta}{sub p}, normalized toroidal beta ({beta}{sub N}), and {tau}{sub E} were obtained at high internal inductance ({ell}{sub i}). During both the ramp and the high confinement phases, fast ion losses were low ({approximately}10%). The loss then increased, correlated with an increase in the anisotropy ratio of perpendicular and parallel plasma pressure that suggests a fast ion loss mechanism coupled to the fast ion parallel energy.

Stallard, B.W.; Casper, T.A.; Fenstermacher, M.E. [Lawrence Livermore National Lab., CA (United States)] [and others

1994-10-01

390

Heat transport in PBX-M high {beta}{sub p} plasmas  

SciTech Connect

PBX-M high beta poloidal discharges routinely transition into the H-mode regime: typically, a quiescent phase followed by an MHD active phase characterize the H-mode period. An analysis of the energy transport during these phases is conducted using the experimental data and the TRANSP code; effective diffusivities are computed to quantify the energy transport of the thermal component of the plasma. Compared to the L-mode, the quiescent H-phase is characterized by a decrease of the thermal ion energy transport and a flattening of the associated effective diffusivity profile. An error analysis is presented. Enhanced fast-ion losses are observed during the MHD active phase: particles in the lower end of the fast-ion energy spectrum with large perpendicular velocity component are predominantly affected. These losses must be taken into account in the analysis in order to reproduce the measured stored energy and time evolution of the neutron production rate during the MHD active phase.

LeBlanc, B.; Kaye, S.; Bell, R.; Fishman, H.; Hatcher, R.; Kaita, R.; Kessel, C.; Kugel, H.; Okabayashi, M.; Paul, S.; Sauthoff, N.; Sesnic, S.; Takahashi, H. [Princeton Univ., NJ (United States). Plasma Physics Lab.; Asakura, N. [Japan Atomic Energy Research Inst., Tokai, Ibaraki, Naka (Japan); Duperrex, P. [Laboratoire pour l`Armement, Bernes (Switzerland); Gammel, G. [Grumman Aerospace Corp., Bethpage, NY (United States); Holland, A. [ARACOR, Sunnyvale, CA (United States); Levinton, F. [Fusion Physics and Technologies, Torrance, CA (United States)

1992-04-01

391

An Optimal Magnetic Coordinate system for High-Beta ST configurations  

NASA Astrophysics Data System (ADS)

In the study of magnetohydrodynamics of magnetically confined systems, it is well known that both analysis and computation are facilitated by an appropriate coordinate system. Specifically, a magnetic coordinate system,(,),where ? is a flux label, ? a poloidal angle and ? a generalized toroidal angle, such that magnetic field lines are straight in (,) space. The generalized toroidal angle, ?, can be related to the Cartesian angle ?, by introducing a periodic function ?(,). This function depends on the choice of Jacobian, and is identically zero when the Jacobian is proportional to x^2. This coordinate is commonly referred to as PEST coordinates. A more general approach to straight field line coordinates is obtained when the Jacobian is defined as J = X^i/?(?) |??|^j. Commonly used coordinate systems are: PEST, with i=2 , j=0; Equal Arcs, with i=j=1; and Hamada with i=j=0. Each of these coordinates has its own merits, but for high beta spherical tori, we identify a new coordinate system, i=0, j=1, which is optimal to this regime. We present results comparing the different coordinate systems in different parameter regimes.

Manickam, Janardhan

2007-11-01

392

Optimization of Kink Stability in High-Beta Quasi-axisymmetric Stellarators  

NASA Astrophysics Data System (ADS)

A key issue for design of Quasi-axisymmetric stellarators( A. Reiman et al, this conference.) (QAS) is the stability of external kink modes driven by pressure-induced bootstrap current. In this work, the 3D MHD stability code TERPSICHORE(W.A. Cooper, Phys. Plasmas 3), 275(1996). is used to calculate the stability of low-n external kink modes in a high-beta QAS. The kink stability is optimized by adjusting plasma boundary shape (i.e., external coil configuration) as well as plasma pressure and current profiles. For this purpose, the TERPSICHORE code has been implemented successfully in an optimizer which maximizes kink stability as well as quasi-symmetry. A key factor for kink stability is rotational transform profile. It is found that the edge magnetic shear is strongly stabilizing. The amount of the shear needed for complete stabilization increases with edge transform. It is also found that the plasma boundary shape plays an important role in the kink stability besides transform profile. The physics mechanisms for the kink stability are being studied by examining the contributions of individual terms in ? W of the energy principle: the field line bending term, the current-driven term, the pressure-driven term, and the vacuum term. Detailed results will be reported.

Fu, G. Y.; Ku, L.-P.; Manickam, J.; Cooper, W. A.

1998-11-01

393

Effect of solvent on absorption spectra of all-trans-{beta}-carotene under high pressure  

SciTech Connect

The absorption spectra of all-trans-{beta}-carotene in n-hexane and carbon disulfide (CS{sub 2}) solutions are measured under high pressure at ambient temperature. The common redshift and broadening in the spectra are observed. Simulation of the absorption spectra was performed by using the time-domain formula of the stochastic model. The pressure dependence of the 0-0 band wavenumber is in agreement with the Bayliss theory at pressure higher than 0.2 GPa. The deviation of the linearity at lower pressure is ascribed to the reorientation of the solvent molecules. Both the redshift and broadening are stronger in CS{sub 2} than that in n-hexane because of the more sensitive pressure dependence of dispersive interactions in CS{sub 2} solution. The effect of pressure on the transition moment is explained with the aid of a simple model involving the relative dimension, location, and orientation of the solute and solvent molecules. The implication of these results for light-harvesting functions of carotenoids in photosynthesis is also discussed.

Liu, W. L.; Zheng, Z. R.; Liu, Z. G.; Zhu, R. B.; Wu, W. Z.; Li, A. H.; Yang, Y. Q. [Center for Condensed Matter Science and Technology, Harbin Institute of Technology, Harbin 150001 (China); Dai, Z. F. [Nanobiotechnology and Biosensor Lab, Bio-X Center, Harbin Institute of Technology, Harbin 150001 (China); Su, W. H. [Center for Condensed Matter Science and Technology, Harbin Institute of Technology, Harbin 150001 (China); Department of Physics, Ji Lin University, Changchun 130023 (China)

2008-03-28

394

Kinetic Alfven wave instability driven by a field-aligned current in high-{beta} plasmas  

SciTech Connect

Including the ion-gyroradius effect, a general low-frequency kinetic dispersion equation is presented, which simultaneously takes account of a field-aligned current and temperature anisotropy in plasmas. Based on this dispersion equation, kinetic Alfven wave (KAW) instability driven by the field-aligned current, which is carried by the field-aligned drift of electrons relative to ions at a drift velocity V{sub D}, is investigated in a high-{beta} plasma, where {beta} is the kinetic-to-magnetic pressure ratio in the plasma. The numerical results show that the KAW instability driven by the field-aligned current has a nonzero growth rate in the parallel wave-number range 0

Chen, L.; Wu, D. J.; Hua, Y. P. [Purple Mountain Observatory, CAS, Nanjing 210008, China and Graduate School, CAS, Beijing 100012 (China); Purple Mountain Observatory, CAS, Nanjing 210008 (China); Purple Mountain Observatory, CAS, Nanjing 210008, China and Graduate School, CAS, Beijing 100012 (China)

2011-10-15

395

High Sensitivity Detection of Xe Isotopes Via Beta-Gamma Coincidence Counting  

Microsoft Academic Search

Measurement of xenon fission product isotopes is a key element in the global network being established to monitor the Comprehensive Nuclear-Test-Ban Treaty. Pacific Northwest National Laboratory has developed an automated system for separating Xe from air which includes a beta-gamma counting system for 131mXe, 133mXe, 133Xe, and 135Xe. Betas and conversion electrons are detected in a plastic scintillation cell containing

Ted W. Bowyer; Justin I. McIntyre; Paul L. Reeder

1999-01-01

396

Insulator materials in high power lasers for inertial fusion: present and future  

SciTech Connect

A summary is given of the important characteristics of currently used insulator materials. Figures of merit for materials needed in future systems are identified. A methodology for identifying and evaluating new materials meeting the stringent performance requirements of future fusion laser systems is outlined.

Krupke, W.F.

1983-11-11

397

Best Tradeoff for High-Resolution Image Fusion to Preserve Spatial Details and Minimize Color Distortion  

Microsoft Academic Search

The fast intensity-hue-saturation {(IHS)} methods can quickly merge massive volumes of data from new satellite imagery. To minimize the color distortion from {IHS} fusion, Choi used a tradeoff parameter in his new fast {IHS} approach to control the spatial and spectral resolution of the fused image. However, the method is not general and requires manual adjustment of the tradeoff parameter

Te-Ming Tu; Wen-Chun Cheng; Chien-Ping Chang; Ping S. Huang; Jyh-Chian Chang

2007-01-01

398

A fusion-based segmentation algorithm for high-resolution panchromatic aerial photography  

Microsoft Academic Search

We propose a mixed segmentation algorithm based on both gray level information and a texture parameter. The definitive k-class image is obtained by means of a simple fusion scheme. Our algorithm considers the following steps: (a) obtainment of an n-class image by means of an algorithm based exclusively on spectral properties, (b) obtainment of a texture image, which may be

J. A. Franco; M. Moctezuma; F. Parmiggiani

2002-01-01

399

High-speed repeating hydrogen pellet injector for long-pulse magnetic confinement fusion experiments  

SciTech Connect

The projected fueling requirements of future magnetic confinement fusion devices [e.g., the International Thermonuclear Experimental Reactor (ITER)] indicate the need for a flexible plasma fueling capability, including both gas puffing and low- and high-speed pellet injection. Conventional injectors, based on single-stage pneumatic guns or centrifuges, can reliably provide frozen pellets (1- to 6-mm-diam sizes) at speeds up to 1.3 km/s and at suitable repetition rates (1 to 10 Hz or greater). Injectors based on two-stage pneumatic guns and ``{ital in situ}`` condensation of hydrogen pellets can reliably achieve velocities over 3 km/s; however, they are not suitable for long-pulse repetitive operations. An experiment in collaboration between ORNL and ENEA Frascati is under way to demonstrate the feasibility of a high-speed ({approx_gt}2 km/s) repeating ({approx}1 Hz) pneumatic pellet injector for long-pulse operation. A test facility has been assembled at ORNL, combining a Frascati repeating two-stage light-gas gun and an ORNL deuterium extruder, equipped with a pellet chambering mechanism/gun barrel assembly. The main issues to be investigated were the strength of extruded deuterium ice as opposed to that produced by {ital in situ} condensation in pipe guns (hence the highest acceleration which can be given to the pellet without fracturing it), and the maximum repetition rate at which the system can operate without degradation in performance. Pellet velocities of up to 2.55 km/s have been achieved in joint experiments at ORNL. A new pressure tailoring valve was developed by the Frascati group for this application and proved to be a crucial component for good performance. Tests carried out in repeating mode, at frequencies of 0.2{endash}0.5 Hz and speeds up to 2.2 km/s, indicate no significant degradation in performance with increasing repetition rate. Some preliminary tests using 3.7 mm pellets gave very encouraging results.

Frattolillo, A.; Migliori, S.; Scaramuzzi, F.; Combs, S.K.; Baylor, L.R.; Foust, C.R.; Gouge, M.J.; Milora, S.L. [ENEA, Dipartimento Innovazione, Settore Fisica Applicata, Centro Ricerche Frascati C.P. 65, 00044 Frascati, Rome (Italy)

1996-05-01

400

Stimulation of collagen gene expression and protein synthesis in murine mesangial cells by high glucose is mediated by autocrine activation of transforming growth factor-beta.  

PubMed Central

Previous investigations have demonstrated that growing mesangial cells in high glucose concentration stimulates extracellular matrix synthesis and also increases the expression of TGF-beta. We tested whether the stimulation of extracellular matrix production is mediated by autocrine activation of TGF-beta, a known prosclerotic cytokine. Addition of neutralizing anti-TGF-beta antibody, but not normal rabbit IgG, significantly reduced the high glucose-stimulated incorporation of 3[H]proline. Denaturing SDS-PAGE revealed that mainly collagen types I and IV were stimulated by high (450 mg/dl) D-glucose. This high glucose-mediated increase in collagen synthesis was reduced by the anti-TGF-beta antibody. Treatment of mesangial cells grown in normal (100 mg/dl) D-glucose with 2 ng/ml recombinant TGF-beta 1 mimicked the effects of high glucose. Furthermore, the anti-TGF-beta antibody significantly reduced the increase in mRNA levels encoding alpha 2(I) and alpha 1(IV) collagens induced by high glucose. Thus, the high glucose-stimulated increase of collagen production in mesangial cells is mediated, at least in part, by autocrine TGF-beta activation. We postulate that the interception of the glomerular activity of TGF-beta may be an effective intervention in the management of diabetic nephropathy. Images

Ziyadeh, F N; Sharma, K; Ericksen, M; Wolf, G

1994-01-01

401

The effects of exchange gas temperature and pressure on the beta-layering process in solid deuterium-tritium fusion fuel  

SciTech Connect

It has recently been shown that when solid tritium is confined in an isothermal enclosure, self-heating due to beta decay drives a net sublimation of material from thick, warmer layers to thin, cooler ones, ultimately resulting in layer thickness uniformity. We have observed this process of beta-layering'' in a 50--50 D-T mixture in both cylindrical and spherical enclosures at temperatures from 19.6 K, down to 11.6 K. The measured time constants are found to depend on the {sup 3}He content as suggested by recent theoretical predictions. When using an enclosure having low thermal conductivity, the ultimate layer uniformity is found to be a strong function of the exchange gas pressure. This is due to the presence of thermal convection in the exchange gas and consequent temperature anisotropy at the solid layer surface. 6 refs., 2 figs., 1 tab.

Hoffer, J.K.; Foreman, L.R. (Los Alamos National Lab., NM (USA)); Simpson, J.D.; Pattinson, T.R. (KMS Fusion, Inc., Ann Arbor, MI (USA))

1990-01-01

402

Liquid lithium target under steady state ultra high heat load of 1 GW\\/m 2 range for International Fusion Materials Irradiation Facility (IFMIF)  

Microsoft Academic Search

International Fusion Materials Irradiation Facility is an accelerator-based neutron source using the D–Li stripping reaction to provide high intensity neutron field with energy of 14 MeV and damage dose rate of around 20 dpa\\/year for fusion materials development. To handle the intense deuterium beam power up to 10 MW which corresponds to ultra high heat flux of 1 GW\\/m2, the

Hiroo Nakamura; Mizuho Ida; Hideo Nakamura; Hiroshi Takeuchi

2003-01-01

403

A fusion power plant without plasma-material interactions  

SciTech Connect

A steady-state fusion power plant is described which avoids the deleterious plasma-material interactions found in D-T fueled tokamaks. It is based on driven p-{sup 11}B fusion in a high-beta closed-field device, the field-reversed configuration (FRC), anchored in a gas-dynamic trap (GDT). The plasma outflow on the open magnetic-field lines is cooled by radiation in the GDT, then channeled through a magnetic nozzle, promoting 3-body recombination in the expansion region. The resulting supersonic neutral exhaust stream flows through a turbine, generating electricity.

Cohen, S.A.

1997-04-01

404

A highly efficient and direct approach for synthesis of enantiopure beta-amino alcohols by reductive cross-coupling of chiral N-tert-butanesulfinyl imines with aldehydes.  

PubMed

A highly efficient and practical approach for the synthesis of optically pure beta-amino alcohols by the SmI2-induced reductive cross-coupling of chiral N-tert-butanesulfinyl imines with aldehydes was developed. This method allows the preparation of a broad range of chiral beta-amino alcohols, including functionalized ones under mild conditions. It provides a straightforward access to enantiopure beta-amino alcohols that are widely applicable in asymmetric synthesis. PMID:16117531

Zhong, Yu-Wu; Dong, Yi-Zhou; Fang, Kai; Izumi, Kenji; Xu, Ming-Hua; Lin, Guo-Qiang

2005-08-31

405

Formation of a long-lived hot field reversed configuration by dynamically merging two colliding high-{beta} compact toroids  

SciTech Connect

A high temperature field reversed configuration (FRC) has been produced in the newly built, world's largest compact toroid (CT) facility, C-2, by colliding and merging two high-{beta} CTs produced using the advanced field-reversed {theta}-pinch technology. This long-lived, stable merged state exhibits the following key properties: (1) apparent increase in the poloidal flux from the first pass to the final merged state, (2) significantly improved confinement compared to conventional {theta}-pinch FRCs with flux decay rates approaching classical values in some cases, (3) strong conversion from kinetic energy into thermal energy with total temperature (T{sub e} + T{sub i}) exceeding 0.5 keV, predominantly into the ion channel. Detailed modeling using a new 2-D resistive magnetohydrodynamic (MHD) code, LamyRidge, has demonstrated, for the first time, the formation, translation, and merging/reconnection dynamics of such extremely high-{beta} plasmas.

Guo, H. Y.; Binderbauer, M. W.; Barnes, D.; Putvinski, S.; Rostoker, N.; Sevier, L.; Tuszewski, M.; Anderson, M. G.; Andow, R.; Bonelli, L.; Brown, R.; Bui, D. Q.; Bystritskii, V.; Clary, R.; Cheung, A. H.; Conroy, K. D.; Deng, B. H.; Dettrick, S. A.; Douglass, J. D.; Feng, P. [Tri Alpha Energy, Inc., P.O. Box 7010, Rancho Santa Margarita, California 92688 (United States)

2011-05-15

406

Construction of hormonally responsive intact cell hybrids by cell fusion: transfer of. beta. -adrenergic receptor and nucleotide regulatory protein(s) in normal and desensitized cells  

SciTech Connect

Fusion of normal, untreated human erythrocytes with desensitized turkey erythrocytes increases isoproterenol stimulation of cyclic (/sup 3/H)AMP accumulation over basal rates. Moreover, pretreatment of the human erythrocytes with cholera toxin before they are fused with desensitized turkey erthythrocytes leads to a large stimulation with isoproterenol. This is even greater and far more rapid than the response obtained if turkey erythrocytes are treated directly with cholera toxin. It is concluded that the stimulation in the fused system is due to the transfer of an ADP-ribosylated subunit of nucleotide regulatory protein.

Schulster, D.; Salmon, D.M.

1985-01-01

407

Effects of Fusion Zone Size on Failure Modes and Performance of Advanced High Strength Steel Spot Welds  

SciTech Connect

This paper examines the effects of fusion zone size on failure modes, static strength and energy absorption of resistance spot welds (RSW) of advanced high strength steels (AHSS). DP800 and TRIP800 spot welds are considered. The main failure modes for spot welds are nugget pullout and interfacial fracture. Partial interfacial fracture is also observed. The critical fusion zone sizes to ensure nugget pull-out failure mode are developed for both DP800 and TRIP800 using the limit load based analytical model and the micro-hardness measurements of the weld cross sections. Static weld strength tests using cross tension samples were performed on the joint populations with controlled fusion zone sizes. The resulted peak load and energy absorption levels associated with each failure mode were studied using statistical data analysis tools. The results in this study show that the conventional weld size of 4 t can not produce nugget pullout mode for both the DP800 and TRIP800 materials. The results also suggest that performance based spot weld acceptance criteria should be developed for different AHSS spot welds.

Sun, Xin; Stephens, Elizabeth V.; Khaleel, Mohammad A.

2006-04-28

408

A High Temperature Electrochemical Energy Storage System Based on Sodium Beta-Alumina Solid Electrolyte (Base)  

SciTech Connect

This report summarizes the work done during the period September 1, 2005 and March 31, 2008. Work was conducted in the following areas: (1) Fabrication of sodium beta{double_prime} alumina solid electrolyte (BASE) using a vapor phase process. (2) Mechanistic studies on the conversion of {alpha}-alumina + zirconia into beta{double_prime}-alumina + zirconia by the vapor phase process. (3) Characterization of BASE by X-ray diffraction, SEM, and conductivity measurements. (4) Design, construction and electrochemical testing of a symmetric cell containing BASE as the electrolyte and NaCl + ZnCl{sub 2} as the electrodes. (5) Design, construction, and electrochemical evaluation of Na/BASE/ZnCl{sub 2} electrochemical cells. (6) Stability studies in ZnCl{sub 2}, SnCl{sub 2}, and SnI{sub 4} (7) Design, assembly and testing of planar stacks. (8) Investigation of the effect of porous surface layers on BASE on cell resistance. The conventional process for the fabrication of sodium ion conducting beta{double_prime}-alumina involves calcination of {alpha}-alumina + Na{sub 2}CO{sub 3} + LiNO{sub 3} at 1250 C, followed by sintering powder compacts in sealed containers (platinum or MgO) at {approx}1600 C. The novel vapor phase process involves first sintering a mixture of {alpha}-alumina + yttria-stabilized zirconia (YSZ) into a dense ceramic followed by exposure to soda vapor at {approx}1450 C to convert {alpha}-alumina into beta{double_prime}-alumina. The vapor phase process leads to a high strength BASE, which is also resistant to moisture attack, unlike BASE made by the conventional process. The PI is the lead inventor of the process. Discs and tubes of BASE were fabricated in the present work. In the conventional process, sintering of BASE is accomplished by a transient liquid phase mechanism wherein the liquid phase contains NaAlO{sub 2}. Some NaAlO{sub 2} continues to remain at grain boundaries; and is the root cause of its water sensitivity. In the vapor phase process, NaAlO{sub 2} is never formed. Conversion occurs by a coupled transport of Na{sup +} through BASE formed and of O{sup 2-} through YSZ to the reaction front. Transport to the reaction front is described in terms of a chemical diffusion coefficient of Na{sub 2}O. The conversion kinetics as a function of microstructure is under investigation. The mechanism of conversion is described in this report. A number of discs and tubes of BASE have been fabricated by the vapor phase process. The material was investigated by X-ray diffraction (XRD), optical microscopy and scanning electron microscopy (SEM), before and after conversion. Conductivity (which is almost exclusively due to sodium ion transport at the temperatures of interest) was measured. Conductivity was measured using sodium-sodium tests as well as by impedance spectroscopy. Various types of both planar and tubular electrochemical cells were assembled and tested. In some cases the objective was to determine if there was any interaction between the salt and BASE. The interaction of interest was mainly ion exchange (possible replacement of sodium ion by the salt cation). It was noted that Zn{sup 2+} did not replace Na+ over the conditions of interest. For this reason much of the work was conducted with ZnCl{sub 2} as the cathode salt. In the case of Sn-based, Sn{sup 2+} did ion exchange, but Sn{sup 4+} did not. This suggests that Sn{sup 4+} salts are viable candidates. These results and implications are discussed in the report. Cells made with Na as the anode and ZnCl{sub 2} as the cathode were successfully charged/discharged numerous times. The key advantages of the batteries under investigation here over the Na-S batteries are: (1) Steel wool can be used in the cathode compartment unlike Na-S batteries which require expensive graphite. (2) Planar cells can be constructed in addition to tubular, allowing for greater design flexibility and integration with other devices such as planar SOFC. (3) Comparable or higher open circuit voltage (OCV) than the Na-S battery. (4) Wider operating temperature range and higher temper

Anil Virkar

2008-03-31

409

Histone hyperacetylation within the beta-globin locus is context-dependent and precedes high-level gene expression.  

PubMed

Active gene promoters are associated with covalent histone modifications, such as hyperacetylation, which can modulate chromatin structure and stabilize binding of transcription factors that recognize these modifications. At the beta-globin locus and several other loci, however, histone hyperacetylation extends beyond the promoter, over tens of kilobases; we term such patterns of histone modifications "hyperacetylated domains." Little is known of either the mechanism by which these domains form or their function. Here, we show that domain formation within the murine beta-globin locus occurs before either high-level gene expression or erythroid commitment. Analysis of beta-globin alleles harboring deletions of promoters or the locus control region demonstrates that these sequences are not required for domain formation, suggesting the existence of additional regulatory sequences within the locus. Deletion of embryonic globin gene promoters, however, resulted in the formation of a hyperacetylated domain over these genes in definitive erythroid cells, where they are otherwise inactive. Finally, sequences within beta-globin domains exhibit hyperacetylation in a context-dependent manner, and domains are maintained when transcriptional elongation is inhibited. These data narrow the range of possible mechanisms by which hyperacetylated domains form. PMID:19690338

Fromm, George; de Vries, Christina; Byron, Rachel; Fields, Jennifer; Fiering, Steven; Groudine, Mark; Bender, M A; Palis, James; Bulger, Michael

2009-08-18

410

The National Spherical Torus Experiment (NSTX) Research Program and Progress Towards High Beta, Long Pulse Operating Scenarios  

SciTech Connect

A major research goal of the National Spherical Torus Experiment is establishing long-pulse, high-beta, high-confinement operation and its physics basis. This research has been enabled by facility capabilities developed over the last two years, including neutral-beam (up to 7 MW) and high-harmonic fast-wave heating (up to 6 MW), toroidal fields up to 6 kG, plasma currents up to 1.5 MA, flexible shape control, and wall preparation techniques. These capabilities have enabled the generation of plasmas with <beta {sub T}> up to 35%. Normalized beta values often exceed the no wall limit, and studies suggest that passive wall mode stabilization is enabling this for broad pressure profiles characteristic of H-mode plasmas. The viability of long, high bootstrap-current fraction operations has been established for ELMing H-mode plasmas with toroidal beta values in excess of 15% and sustained for several current relaxation times. Improvements in wall conditioning and fueling are likely contributing to a reduction in H-mode power thresholds. Electron thermal conduction is the dominant thermal loss channel in auxiliary-heated plasmas examined thus far. High-harmonic fast-wave (HHFW) effectively heats electrons, and its acceleration of fast beam ions has been observed. Evidence for HHFW current drive is by comparing of the loop voltage evolution in plasmas with matched density and temperature profiles but varying phases of launched HHFW waves. A peak heat flux of 10 MW/m superscript ''2'' has been measured in the H-mode, with large asymmetries in the power deposition being observed between the inner and outer strike points. Noninductive plasma start-up studies have focused on coaxial helicity injection. With this technique, toroidal currents up to 400 kA have been drive