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1

Fusion alpha-particle losses in a high-beta rippled tokamak  

NASA Astrophysics Data System (ADS)

In tokamak plasmas, the confinement of energetic ions depends on the magnetic field structure. If the plasma pressure is finite, the equilibrium current (i.e., the Pfirsch-Schlter current and diamagnetic current) flows in the plasma to maintain the magnetohydrodynamic (MHD) equilibrium. These plasma currents generate poloidal and toroidal magnetic field and alter the field structure. Moreover, if we consider the non-axisymmetry of magnetic field structures such as toroidal field (TF) ripples, the non-axisymmetric component of the equilibrium current can alter TF ripples themselves. When the plasma beta becomes high, the changes in the field structure due to the equilibrium current might affect the confinement of energetic ions significantly. We intend to clarify how these currents alter the field structure and affect the confinement of alpha particles in high-beta plasma. The MHD equilibrium is calculated using VMEC and the orbits of fusion alpha particles are followed by using the fully three-dimensional magnetic field orbit-following Monte Carlo code. In relatively low-beta plasma (e.g., the volume-averaged beta value ????2%), the changes in the magnetic field component due to the plasma current negligibly affect the confinement of alpha particles except for the Shafranov shift effect. However, for ????3%, the diamagnetic effect reduces the magnetic field strength and significantly increases alpha-particle losses. In these high-beta cases, the non-axisymmetric field component generated by the equilibrium current also increases these losses, but not as effectively as compared to the diamagnetic effect.

Bunno, M.; Nakamura, Y.; Suzuki, Y.; Shinohara, K.; Matsunaga, G.; Tani, K.

2013-08-01

2

Fusion alpha-particle losses in a high-beta rippled tokamak  

SciTech Connect

In tokamak plasmas, the confinement of energetic ions depends on the magnetic field structure. If the plasma pressure is finite, the equilibrium current (i.e., the Pfirsch-Schlter current and diamagnetic current) flows in the plasma to maintain the magnetohydrodynamic (MHD) equilibrium. These plasma currents generate poloidal and toroidal magnetic field and alter the field structure. Moreover, if we consider the non-axisymmetry of magnetic field structures such as toroidal field (TF) ripples, the non-axisymmetric component of the equilibrium current can alter TF ripples themselves. When the plasma beta becomes high, the changes in the field structure due to the equilibrium current might affect the confinement of energetic ions significantly. We intend to clarify how these currents alter the field structure and affect the confinement of alpha particles in high-beta plasma. The MHD equilibrium is calculated using VMEC and the orbits of fusion alpha particles are followed by using the fully three-dimensional magnetic field orbit-following Monte Carlo code. In relatively low-beta plasma (e.g., the volume-averaged beta value ?2%), the changes in the magnetic field component due to the plasma current negligibly affect the confinement of alpha particles except for the Shafranov shift effect. However, for ?3%, the diamagnetic effect reduces the magnetic field strength and significantly increases alpha-particle losses. In these high-beta cases, the non-axisymmetric field component generated by the equilibrium current also increases these losses, but not as effectively as compared to the diamagnetic effect.

Bunno, M.; Nakamura, Y. [Graduate School of Energy Science, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan)] [Graduate School of Energy Science, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Suzuki, Y. [National Institute for Fusion Science, Toki 509-5292 (Japan)] [National Institute for Fusion Science, Toki 509-5292 (Japan); Shinohara, K.; Matsunaga, G. [Japan Atomic Energy Agency, Naka, Ibaraki 311-0193 (Japan)] [Japan Atomic Energy Agency, Naka, Ibaraki 311-0193 (Japan); Tani, K. [Nippon Advanced Technology, Naka, Ibaraki 311-0102 (Japan)] [Nippon Advanced Technology, Naka, Ibaraki 311-0102 (Japan)

2013-08-15

3

Inhibiting HIV fusion with a beta-peptide foldamer.  

PubMed

Linear peptides derived from the HIV gp41 C-terminus (C-peptides), such as the 36-residue Fuzeon, are potent HIV fusion inhibitors. These molecules bind to the N-peptide region of gp41 and inhibit an intramolecular protein-protein interaction that powers fusion of the viral and host cell membranes. The N-peptide region contains a surface pocket that is occupied in the post-fusion state by three alpha-helical residues found near the gp41 C-terminus: Trp628, Trp631, and Ile635-the WWI epitope. Here, we describe a set of beta3-decapeptides (betaWWI-1-4) in which the WWI epitope is presented on one face of a short 14-helix stabilized by macrodipole neutralization and side chain-side chain salt bridges. betaWWI-1-4 bind in vitro to IZN17, a validated gp41 model, and inhibit syncytia formation in cell culture. Molecules lacking a complete WWI functional epitope neither bind IZN17 nor inhibit syncytia formation. These results provide evidence that short beta-peptide 14-helices can inhibit an intramolecular protein-protein interaction in vivo. Molecules related to betaWWI-1-4 could represent starting points for the development of highly potent inhibitors or antigens effective against HIV or other viruses, including SARS, Ebola, HRSV, and influenza, that employ common fusion mechanisms. PMID:16173723

Stephens, Olen M; Kim, Sunghwan; Welch, Brett D; Hodsdon, Michael E; Kay, Michael S; Schepartz, Alanna

2005-09-28

4

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

5

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

6

Identification of a beta3-peptide HIV fusion inhibitor with improved potency in live cells.  

PubMed

We recently reported a beta(3)-decapeptide, betaWWI-1, that binds a validated gp41 model in vitro and inhibits gp41-mediated fusion in cell culture. Here we report six analogs of betaWWI-1 containing a variety of non-natural side chains in place of the central tryptophan of the WWI-epitope. These analogs were compared on the basis of both gp41 affinity in vitro and fusion inibition in live, HIV-infected cells. One new beta(3)-peptide, betaWXI-a, offers a significantly improved CC(50)/EC(50) ratio in the live cell assay. PMID:19497744

Bautista, Arjel D; Stephens, Olen M; Wang, Ligong; Domaoal, Robert A; Anderson, Karen S; Schepartz, Alanna

2009-07-15

7

Neoclassical transport in high [beta] tokamaks  

SciTech Connect

Neoclassical, transport in high [beta] large aspect ratio tokamaks is calculated. The variational method introduced by Rosenbluth, et al., is used to calculate the full Onsager matrix in the banana regime. These results are part of a continuing study of the high [beta] large aspect ratio equilibria introduced in Cowley, et al. All the neoclassical coefficients are reduced from their nominal low [beta] values by a factor ([var epsilon]/q[sup 2][beta])[sup [1/2

Cowley, S.C.

1992-12-01

8

Laser Fusion Energy The High Average Power  

E-print Network

Laser Fusion Energy and The High Average Power Program John Sethian Naval Research Laboratory Dec for Inertial Fusion Energy with lasers, direct drive targets and solid wall chambers Lasers DPPSL (LLNL) Kr posters Snead Payne #12;Laser(s) Goals 1. Develop technologies that can meet the fusion energy

9

Fusion zone microstructure and porosity in electron beam welds of an {alpha} + {beta} titanium alloy  

SciTech Connect

The effect of electron beam welding parameters on fusion zone (FZ) microstructure and porosity in a Ti-6.8 Al-3.42 Mo-1.9 Zr-0.21 Si alloy (Russian designation VT 9) has been investigated. It has been observed that the FZ grain width increased continuously with increase in heat input when the base metal was in the {beta} heat-treated condition, while in the {alpha} + {beta} heat-treated base metal welds, the FZ grain width increased only after a threshold energy input. The difference is attributed to both the weld thermal cycle and the pinning effect of equiaxed primary alpha on grain growth in the heat-affected zone (HAZ) of {alpha} + {beta} heat-treated base metal. Postweld heat treatment (PWHT) in the subtransus and supertransus regions did not alter the columnar grain morphology in the FZ, possibly due to the lack of enough driving force for the formation of new grains by the breaking up of the columnar grains and grain boundary movement for grain growth. The highest porosity was observed at intermediate welding speeds. At low speeds, a majority of pores formed at the fusion boundary, while at high speeds, occurrence of porosity was maximum at the weld center. The trends on porosity can be explained on the basis of solubility of hydrogen in titanium as a function of temperature and the influence of weld thermal cycle on nucleation, growth, and escape of hydrogen gas bubbles. The porosity at slow welding speeds is low because sufficient time exists for the nucleation, growth, and escape of hydrogen gas bubbles, while insufficient time exists for the nucleation of gas bubbles at high welding speeds. The effect of pickling of joint surface, vacuum annealing of the base metal, and successive remelting of the weld metal has also been investigated.

Mohandas, T.; Banerjee, D. [Defence Metallurgical Research Lab., Hyderabad (India); Kutumba Rao, V.V. [Banaras Hindu Univ., Varanasi (India)

1999-03-01

10

Fusion of the Saccharomyces cerevisiae leu2 gene to an Escherichia coli beta-galactosidase gene.  

PubMed Central

The promoter and translation initiation region of the Saccharomyces cerevisiae leu2 gene was fused to the Escherichia coli beta-galactosidase gene. This fusion located the control region of the leu gene and orientated its direction of expression. When the fusion was placed into yeast cells, beta-galactosidase was expressed under the same regulatory pattern as the original leu2 gene product: its synthesis was repressed in the presence of leucine and threonine. Sensitive chromogenic substrates for beta-galactosidase were used to detect expression in isolated colonies growing on agar medium. Mutant yeast cells with increased beta-galactosidase activity were identified by the color of the colonies they formed. One class of mutants obtained appeared to affect ars1 plasmid maintenance, and another class appeared to affect beta-galactoside uptake. PMID:6406836

Martinez-Arias, A E; Casadaban, M J

1983-01-01

11

A high-fluence fusion neutron source  

SciTech Connect

A conceptual design of a D-T fusion facility for continuous production of 14-MeV neutron wall loading from 5 to 10 MW/m/sup 2/ at the plasma surface is presented. In this design, D-T neutrons are produced in a linear, two-component plasma formed by neutral beam irradiation of a fully ionized warm plasma target. The beam energy, which is deposited in the center, is transferred to the warm plasma mainly by electron drag and is conducted along the target plasma column to end regions where it is absorbed in neutral gas at high pressure. The target plasma is operated in a regime where electron thermal conduction along the column is the controlling energy-loss process. The loss rate is minimized by adjusting the diameter and length of the plasma column. A substantial gradient in T/sub e/ along the column results in recombination of the plasma to gas in the end-regions before impact on the end walls. The resultant hot gas is cooled by contact with large-area heat exchangers. In this way, the large steady-state heat load from the injected neutral beams is diffused and removed at tolerable heat flux levels. The reacting plasma is essentially an extrapolation of the 2XIIB high-..beta.. plasma to higher magnetic field, ion energy, and density. 12 refs., 4 figs.

Coensgen, F.H.; Casper, T.A.; Correll, D.L.; Damm, C.C.; Futch, A.H.; Logan, B.G.; Molvik, A.W.; Bulmer, R.H.

1988-02-17

12

Neoclassical transport in high {beta} tokamaks  

SciTech Connect

Neoclassical, transport in high {beta} large aspect ratio tokamaks is calculated. The variational method introduced by Rosenbluth, et al., is used to calculate the full Onsager matrix in the banana regime. These results are part of a continuing study of the high {beta} large aspect ratio equilibria introduced in Cowley, et al. All the neoclassical coefficients are reduced from their nominal low {beta} values by a factor ({var_epsilon}/q{sup 2}{beta}){sup {1/2}} II. This factor is the ratio of plasma volume in the boundary layer to the volume in the core. The fraction of trapped particles on a given flux surface (f{sub t}) is also reduced by this factor so that {approximately} {sub ({var_epsilon}}/q{sup 2}{beta}){sup {1/2}}. Special attention is given to the current equation, since this is thought to be relevant at low 3 and therefore may also be relevant at high {beta}. The bootstrap current term is found to exceed the actual current by a factor of the square root of the aspect ratio.

Cowley, S.C.

1992-12-01

13

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

14

Structural Evidence for Evolution of the beta\\/alpha Barrel Scaffold by Gene Duplication and Fusion  

Microsoft Academic Search

The atomic structures of two proteins in the histidine biosynthesis pathway consist of beta\\/alpha barrels with a twofold repeat pattern. It is likely that these proteins evolved by twofold gene duplication and gene fusion from a common half-barrel ancestor. These ancestral domains are not visible as independent domains in the extant proteins but can be inferred from a combination of

Dietmar Lang; Ralf Thoma; Martina Henn-Sax; Reinhard Sterner; Matthias Wilmanns

2000-01-01

15

High beta-N experiments at JET  

NASA Astrophysics Data System (ADS)

JET has investigated the performance potential and limitations of highly triangular plasmas relevant to fully non-inductive tokamak operation. The q-profile shape has been varied from cases with highly negative core magnetic shear to low shear with q0 close to 1, allowing the effect on confinement and stability to be studied. Operation with beta-N above the no-wall `limit' has been demonstrated for durations comparable with the resistive time and direct measurements of the no-wall beta have been developed as a tool for systematic performance optimization. Regimes have been developed with ITBs at reduced plasma current and toroidal field (1.2-1.5MA/2.3-2.7T) to obtain high values of beta-N and beta-P with either impurity seeding or quasi-double-null plasma configurations used to mitigate ELMs. The importance of the q-profile shape for performance optimization has been demonstrated in plasmas without ITBs (1.2MA/1.8T) with low values of minimum q (1-2) providing access to the highest beta-N (above 3).

Challis, Clive

2007-11-01

16

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

17

Macroscopic stability of high beta MAST plasmas  

Microsoft Academic Search

The high-beta capability of the spherical tokamak, coupled with a suite of world-leading diagnostics on MAST, has facilitated significant improvements in the understanding of performance-limiting core instabilities in high performance plasmas. For instance, the newly installed motional Stark effect diagnostic, with radial resolution <25 mm, has enabled detailed study of saturated long-lived modes in hybrid scenarios. Similarly, the upgraded Thomson

I. T. Chapman; W. A. Cooper; J. P. Graves; M. P. Gryaznevich; R. J. Hastie; T. C. Hender; D. F. Howell; M.-D. Hua; G. T. A. Huysmans; D. L. Keeling; Y. Q. Liu; H. F. Meyer; C. A. Michael; S. D. Pinches; S. Saarelma; S. A. Sabbagh

2011-01-01

18

Fusion zone microstructure and porosity in electron beam welds of an alpha+beta titanium alloy  

Microsoft Academic Search

The effect of electron beam welding parameters on fusion zone (FZ) microstructure and porosity in a Ti -6.8 Al -3.42 Mo -1.9 Zr -0.21 Si alloy (Russian designation VT 9) has been investigated. It has been observed that the FZ grain width increased continuously with increase in heat input when the base metal was in the beta heat-treated condition, while

T. Mohandas; D. Banerjee; V. V. Kutumba Rao

1999-01-01

19

High-Gain Magnetized Inertial Fusion  

NASA Astrophysics Data System (ADS)

Magnetized inertial fusion (MIF) could substantially ease the difficulty of reaching plasma conditions required for significant fusion yields, but it has been widely accepted that the gain is not sufficient for fusion energy. Numerical simulations are presented showing that high-gain MIF is possible in cylindrical liner implosions based on the MagLIF concept [S. A. Slutz et al Phys. Plasmas 17, 056303 (2010)PHPAEN1070-664X10.1063/1.3333505] with the addition of a cryogenic layer of deuterium-tritium (DT). These simulations show that a burn wave propagates radially from the magnetized hot spot into the surrounding much denser cold DT given sufficient hot-spot areal density. For a drive current of 60 MA the simulated gain exceeds 100, which is more than adequate for fusion energy applications. The simulated gain exceeds 1000 for a drive current of 70 MA.

Slutz, Stephen A.; Vesey, Roger A.

2012-01-01

20

High-gain magnetized inertial fusion.  

PubMed

Magnetized inertial fusion (MIF) could substantially ease the difficulty of reaching plasma conditions required for significant fusion yields, but it has been widely accepted that the gain is not sufficient for fusion energy. Numerical simulations are presented showing that high-gain MIF is possible in cylindrical liner implosions based on the MagLIF concept [S. A. Slutz et al Phys. Plasmas 17, 056303 (2010)] with the addition of a cryogenic layer of deuterium-tritium (DT). These simulations show that a burn wave propagates radially from the magnetized hot spot into the surrounding much denser cold DT given sufficient hot-spot areal density. For a drive current of 60 MA the simulated gain exceeds 100, which is more than adequate for fusion energy applications. The simulated gain exceeds 1000 for a drive current of 70 MA. PMID:22324693

Slutz, Stephen A; Vesey, Roger A

2012-01-13

21

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

22

Preliminary evaluation of beta-spodumene as a fusion reactor structural material  

SciTech Connect

Beta-spodumene was investigated as a candidate material for use in fusion reactor environments. Properties which support the use of beta-spodumene include good thermal shock resistance, a very low coefficient of thermal expansion, a low-Z composition which would result in minimum impact on the plasma, and flexibility in fabrication processes. Specimens were irradiated in the Advanced Test Reactor (ATR) to a fluence of 5.3 x 10/sup 22/ n/m/sup 2/, E > 0.1 MeV, and 4.9 x 10/sup 23/ n/m/sup 2/ thermal fluence in order to obtain a preliminary evaluation of the impact of irradiation on the material. Preliminary data indicate that the mechanical properties of beta-spodumene are little affected by irradiation. Gas production and release have also been investigated.

Kelsey, P.V. Jr.; Schmunk, R.E.; Henslee, S.P.

1981-01-01

23

High precision measurements of Na-26 beta(-) decay  

E-print Network

High-precision measurements of the half-life and beta-branching ratios for the beta(-) decay of Na-26 to Mg-26 have been measured in beta-counting and gamma-decay experiments, respectively. A 4 pi proportional counter and fast tape transport system...

Grinyer, GF; Svensson, CE; Andreoiu, C.; Andreyev, AN; Austin, RAE; Ball, GC; Chakrawarthy, RS; Finlay, P.; Garrett, PE; Hackman, G.; Hardy, John C.; Hyland, B.; Iacob, VE; Koopmans, KA; Kulp, WD; Leslie, JR; Macdonald, JA; Morton, AC; Ormand, WE; Osborne, CJ; Pearson, CJ; Phillips, AA; Sarazin, F.; Schumaker, MA; Scraggs, HC; Schwarzenberg, J.; Smith, MB; Valiente-Dobon, JJ; Waddington, JC; Wood, JL; Zganjar, EF.

2005-01-01

24

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

SciTech Connect

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, {beta}{sub T}=3.6%, normalized beta, {beta}{sub N}=3.5, and confinement factor, H{sub 89}=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 ({tau}{sub CR}). Stationary conditions are maintained in similar discharges ({approx}90% noninductive), limited only by the 2 s duration (1{tau}{sub 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. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6969 (United States); Wade, M.R.; Greenfield, C.M.; Luce, T.C.; Ferron, J.R.; St John, H.E.; DeBoo, J.C.; Osborne, T.H.; Petty, C.C.; Politzer, P.A.; Burrell, K.H.; Gohil, P.; Gorelov, I.A.; Groebner, R.J.; Hyatt, A.W.; Kajiwara, K.; La Haye, R.J.; Lao, L.L.; Leonard, A.W.; Lohr, J. [General Atomics, P. O. Box 85608, San Diego, California 92186-5608 (United States)] (and others)

2006-05-15

25

High Energy Space Propulsion based on Magnetized Target Fusion  

Microsoft Academic Search

Magnetized Target Fusion (MTF) is a new entry into the fusion propulsion arena that promises low-cost development and rapid deployment using existing facilities and technology. Plasma-jet driven MTF has a number of features which make it attractive as a space propulsion system. These features include, low system mass and volume, high Isp and thrust, and efficient fusion drivers leading to

F. Thio

1999-01-01

26

Stability Limits of High-Beta Plasmas in DIII-D  

SciTech Connect

Stability at high beta is an important requirement for a compact, economically attractive fusion reactor. DIII-D experiments have shown that ideal magnetohydrodynamic (MHD) theory is an accurate predictor of the ultimate stability limits for tokamaks, and the Troyon scaling law has provided a useful approximation of ideal stability limits for discharges with 'conventional' profiles. However, variation of the discharge shape, pressure profile, and current density profile can lead to ideal MHD beta limits that differ significantly from simple Troyon scaling. The need for profiles consistent with steady-state operation places an important additional constraint on plasma stability. Nonideal effects can also be important and must be taken into account. For example, neoclassical tearing modes (NTMs), resulting from plasma resistivity and the nonlinear effects of the bootstrap current, can become unstable at beta values well below the ideal MHD limit. DIII-D experiments are now entering a new era of unprecedented control over plasma stability, including suppression of NTMs by localized current drive at the island location, and direct feedback stabilization of kink modes with a resistive wall. The continuing development of physics understanding and control tools holds the potential for stable, steady-state fusion plasmas at high beta.

Strait, E.J. [General Atomics (United States)

2005-10-15

27

Beta1,6-branched oligosaccharides regulate melanin content and motility in macrophage-melanoma fusion hybrids.  

PubMed

In previous studies, fusion of peritoneal macrophages or blood monocytes with mouse melanoma cells produced hybrids with upregulated expression of the glycosyltransferase beta1,6-N-acetylglucosaminyltransferase V (GnT-V) and its enzymatic product, beta1,6-branched oligosaccharides. This correlated with marked increases in motility, metastatic potential and, surprisingly, melanin content. This study was designed to establish direct roles for beta1,6-branched oligosaccharides in melanogenesis and motility. The levels of beta1,6-branched oligosaccharides were lowered by transfecting beta1,4-N-acetylglucosaminyltransferase III, a competitive inhibitor of GnT-V. beta1,4-N-acetylglucosaminyltransferase III transfection virtually eliminated melanin production and markedly decreased chemotactic motility. This implied that the metastatic and melanogenic phenotypes in hybrids were each upregulated by beta1,6-branched oligosaccharides. Although roles for beta1,6-branched oligosaccharides in motility and metastasis have been reported previously, this is the first study to directly implicate these structures in melanogenesis. Although drawn from experimental models, the findings might explain the well known hypermelanotic regions of human cutaneous malignant melanoma as hypermelanotic cutaneous malignant melanoma cells are rich in beta1,6-branched oligosaccharides. They might also explain why melanogenesis pathways differ between malignant and normal melanocytes as GnT-V is a myeloid-associated enzyme that is aberrantly expressed in melanoma cells but not in normal melanocytes. PMID:17235237

Chakraborty, Ashok K; Pawelek, John

2007-02-01

28

High density, high magnetic field concepts for compact fusion reactors  

SciTech Connect

One rather discouraging feature of our conventional approaches to fusion energy is that they do not appear to lend themselves to a small reactor for developmental purposes. This is in contrast with the normal evolution of a new technology which typically proceeds to a full scale commercial plant via a set of graduated steps. Accordingly` several concepts concerned with dense plasma fusion systems are being studied theoretically and experimentally. A common aspect is that they employ: (a) high to very high plasma densities ({approximately}10{sup 16}cm{sup -3} to {approximately}10{sup 26}cm{sup -3}) and (b) magnetic fields. If they could be shown to be viable at high fusion Q, they could conceivably lead to compact and inexpensive commercial reactors. At least, their compactness suggests that both proof of principle experiments and development costs will be relatively inexpensive compared with the present conventional approaches. In this paper, the following concepts are considered: (1) The staged Z-pinch, (2) Liner implosion of closed-field-line configurations, (3) Magnetic ``fast`` ignition of inertial fusion targets, (4) The continuous flow Z-pinch.

Perkins, L.J. [and others

1996-10-11

29

High beta diversity of bacteria in the shallow terrestrial subsurface.  

PubMed

While there have been a vast number of studies on bacterial alpha diversity in the shallow terrestrial subsurface, beta diversity - how the bacterial community composition changes with spatial distance - has received surprisingly limited attention. Here, bacterial beta diversity and its controlling factors are investigated by denaturing gradient gel electrophoresis and cloning of samples from a 700-cm-long sediment core, the lower half of which consisted of marine-originated sediments. According to canonical correspondence analysis with variation partitioning, contemporary environmental variables explain beta diversity in a greater proportion than depth. However, we also found that community similarity decayed significantly with spatial distance and the slopes of the distance-decay relationships are relatively high. The high beta diversity indicates that the bacterial distribution patterns are not only controlled by contemporary environments, but also related to historical events, that is, dispersal or depositional history. This is highlighted by the different beta diversity patterns among studied sediment layers. We thus conclude that the high beta diversity in the shallow terrestrial subsurface is a trade-off between historical events and environmental heterogeneity. Furthermore, we suggest that the high beta diversity of bacteria is likely to be recapitulated in other terrestrial sites because of the great frequency of high geochemical and/or historical variations along depth. PMID:18833648

Wang, Jianjun; Wu, Yucheng; Jiang, Hongchen; Li, Chunhai; Dong, Hailiang; Wu, Qinglong; Soininen, Janne; Shen, Ji

2008-10-01

30

High density, high magnetic field concepts for compact fusion reactors  

SciTech Connect

During the past year, several concepts concerned with dense plasma fusion systems have been theoretically/numerically re-examined at LLNL, with a conclusion that they may become strong candidates for future alternatives research programs. A common feature of these schemes is that they employ (a) plasmas with densities ranging from {approximately}10{sup 16} cm{sup {minus}3} up to ICF-like densities ({approximately} 10{sup 26} cm{sup {minus}3}) and (b) magnetic fields. Their salient feature is also that, if successful, they would give rise to a compact and inexpensive reactor. Their compactness means also that the proof-of-principle experiment will be relatively inexpensive; the same is true for the developmental cost. Specifically, the authors consider the following concepts: (1) liner implosion of the closed-field-line configurations; (2) flow-through pinch; (3) magnetic ignition of inertial fusion. Although the first two concepts have been known in some form for a decade or so, new developments in fusion-related science and technology (e.g., direct experimental demonstration of a high-convergence 3D liner implosion and theoretical identification of a strong favorable effect of the shear flows on the stability of the pinches) certainly make them much more attractive than before. The third concept that emerged during last one or two years, also relies on a great progress in the understanding of the properties of high-density magnetized plasma. A brief description of each concept is given here.

Perkins, L.J.; Drake, R.P.; Eddleman, J.L.; Hammer, J.H.; Hartman, C.W.; Mattor, N.; Ryutov, D.D. [Lawrence Livermore National Lab., CA (United States); Newton, A.A. [Culham Lab., Abingdon (United Kingdom); Shumlak, U. [Univ. of Washington, Seattle, WA (United States)

1996-03-01

31

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

32

Progress toward high-gain laser fusion  

NASA Astrophysics Data System (ADS)

A 1985 to 1986 Review of the U.S. 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 to 10 percent of drive energy, depending on target design) and achieve enough pulse-shaping accuracy (approximately 10 percent, 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 percent), and can 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 DOE is planning to complete a 10-MJ laboratory microfusion facility to demonstrate high-gain ICF in the laboratory within a decade.

Storm, Erik

1988-09-01

33

High Current Ion Source Development for Heavy Ion Fusion  

Microsoft Academic Search

We are developing high-current-density high-brightness sources for Heavy Ion Fusion applications. Heavy ion driven inertial fusion requires beams of high brightness in order to achieve high power density at the target for high target gain. At present, there are no existing ion source types that can readily meet all the driver HIF requirements, though sources exist which are adequate for

G A Westenskow; D P Grote; J W Kwan

2003-01-01

34

High fusion power steady state operation in JET DT plasmas  

Microsoft Academic Search

Because of its large size, single null divertor and flexible magnetic geometry, JET is capable of producing the most reactor relevant plasmas of any present generation tokamak. In recent DT experiments, the fusion performance of these plasmas was tested for the first time. Over 4 MW of fusion power was produced in a high power, steady state pulse of 5

L. D. Horton; R. Sartori; B. Balet; R. V. Budny; J. P. Christiansen; S. Clement; G. D. Conway; J. G. Cordey; G. M. Fishpool; J. Lingertat; C. G. Lowry; C. F. Maggi; M. J. Mantsinen; V. Riccardo; G. Saibene; P. Smeulders; R. J. Smith; K. Thomsen; M. G. von Hellermann

1999-01-01

35

An EMD-IHS model for high resolution image fusion  

NASA Astrophysics Data System (ADS)

High resolution image fusion is a significant focus in the field of the image processing. A new image fusion model is presented based on the characteristic level of Empirical Mode Decomposition (EMD). The IHS transform of the multi-spectral image firstly gives the intensity image. Thereafter, the 2D EMD in terms of row-column extension of the 1D EMD model was used to decompose the detail scale image and coarse scale image from the high resolution band image and the intensity image. At last, fused intensity image is obtained by reconstruction with high frequency of high-resolution image and low frequency of intensity image and IHS inverse transform result in fused image. After presenting EMD principle, multi-scale decomposition and reconstruction algorithm of 2D EMD is defined and fusion technique scheme is advanced based on EMD. Panchromatic band and multi-spectral band3,2,1 of QUICKBIRD are used to assess the quality of the fusion algorithm. After selecting appropriate Intrinsic Mode Function(IMF) for the merger on the basis of EMD analysis on specific row (colum) pixel gray value series, the fusion scheme gives fused image, which is compared with generally used fusion algorithms (Wavelet, IHS,Brovey). The objectives of image fusion include enhancing the visibility of the image and improving the spatial resolution and the spectral information of the original images. For assessing quality of an image after fusion, information entropy and standard deviation are applied to assess spatial details of the fused images and correlation coefficient, bias index and warping degree for measuring distortion between the original image and fused image in terms of spectral information. For all proposed fusion algorithms, better results are obtained when EMD algorithm is used to perform the fusion experience.

Wang, Jian; Xu, Changhui; Zhang, Jixian; Liu, Zhengjun

2007-06-01

36

Heavy ion fusion science research for high energy density physics and fusion applications  

Microsoft Academic Search

During the past two years, the U.S. heavy ion fusion science program has made significant experimental and theoretical progress in simultaneous transverse and longitudinal beam compression, ion-beam-driven warm dense matter targets, high brightness beam transport, advanced theory and numerical simulations, and heavy ion target designs for fusion. First experiments combining radial and longitudinal compression of intense ion beams propagating through

B. G. Logan; J. J. Barnard; F. M. Bieniosek; R. H. Cohen; J. E. Coleman; R. C. Davidson; P. C. Efthimion; A. Friedman; E. P. Gilson; W. G. Greenway; L. Grisham; D. P. Grote; E. Henestroza; D. H. H. Hoffmann; I. D. Kaganovich; M. K. Covo; J. W. Kwan; K. N. La Fortune; E. P. Lee; M. Leitner; S. M. Lund; A. W. Molvik; P. Ni; G. E. Penn; L. J. Perkins; H. Qin; P. K. Roy; A. B. Sefkow; P. A. Seidl; W. Sharp; E. A. Startsev; J.-L. Vay; W. L. Waldron; J. S. Wurtele; D. Welch; G. A. Westenskow; S. S. Yu

2008-01-01

37

Heavy ion fusion science research for high energy density physics and fusion applications  

Microsoft Academic Search

During the past two years, the U.S. heavy ion fusion science program has made significant experimental and theoretical progress in simultaneous transverse and longitudinal beam compression, ion-beam-driven warm dense matter targets, high brightness beam transport, advanced theory and numerical simulations, and heavy ion target designs for fusion. First experiments combining radial and longitudinal compression of intense ion beams propagating through

B. G. LOGAN; F. M. Bieniosek; J. J. Barnard; R. H. Cohen; J. E. Coleman; R. C. Davidson; P. C. Efthimion; A. Friedman; E. P. Gilson; W. G. Greenway; L. Grisham; D. P. Grote; E. Henestroza; D. H. H. Hoffmann; I. D. Kaganovich; M. Kireeff Covo; J. W. Kwan; K. N. LaFortune; E. P. Lee; M. Leitner; S. M. Lund; A. W. Molvik; P. Ni; G. E. Penn; L. J. Perkins; H. Qin; P. K. Roy; A. B. Sefkow; P. A. Seidl; W. Sharp; E. A. Startsev; D. Varentsov; J.-L. Vay; W. L. Waldron; J. S. Wurtele; D. Welch; G. A. Westenskow; S. S. Yu

2007-01-01

38

High-density lipoprotein, beta cells, and diabetes.  

PubMed

High-density lipoproteins (HDLs) exert a series of potentially beneficial effects on many cell types including anti-atherogenic actions on the endothelium and macrophage foam cells. HDLs may also exert anti-diabetogenic functions on the beta cells of the endocrine pancreas, notably by potently inhibiting stress-induced cell death and enhancing glucose-stimulated insulin secretion. HDLs have also been found to stimulate insulin-dependent and insulin-independent glucose uptake into skeletal muscle, adipose tissue, and liver. These experimental findings and the inverse association of HDL-cholesterol levels with the risk of diabetes development have generated the notion that appropriate HDL levels and functionality must be maintained in humans to diminish the risks of developing diabetes. In this article, we review our knowledge on the beneficial effects of HDLs in pancreatic beta cells and how these effects are mediated. We discuss the capacity of HDLs to modulate endoplasmic reticulum stress and how this affects beta-cell survival. We also point out the gaps in our understanding on the signalling properties of HDLs in beta cells. Hopefully, this review will foster the interest of scientists in working on beta cells and diabetes to better define the cellular pathways activated by HDLs in beta cells. Such knowledge will be of importance to design therapeutic tools to preserve the proper functioning of the insulin-secreting cells in our body. PMID:24903496

von Eckardstein, Arnold; Widmann, Christian

2014-08-01

39

Heavy ion fusion science research for high energy density physics and fusion applications  

SciTech Connect

During the past two years, the U.S. heavy ion fusion science program has made significant experimental and theoretical progress in simultaneous transverse and longitudinal beam compression, ion-beam-driven warm dense matter targets, high brightness beam transport, advanced theory and numerical simulations, and heavy ion target designs for fusion. First experiments combining radial and longitudinal compression of intense ion beams propagating through background plasma resulted in on-axis beam densities increased by 700X at the focal plane. With further improvements planned in 2007, these results will enable initial ion beam target experiments in warm dense matter to begin next year at LBNL. We are assessing how these new techniques apply to low-cost modular fusion drivers and higher-gain direct-drive targets for inertial fusion energy.

LOGAN, B.G.; Logan, B.G.; Bieniosek, F.M.; Barnard, J.J.; Cohen, R.H.; Coleman, J.E.; Davidson, R.C.; Efthimion, P.C.; Friedman, A.; Gilson, E.P.; Greenway, W.G.; Grisham, L.; Grote, D.P.; Henestroza, E.; Hoffmann, D.H.H.; Kaganovich, I.D.; Kireeff Covo, M.; Kwan, J.W.; LaFortune, K.N.; Lee, E.P.; Leitner, M.; Lund, S.M.; Molvik, A.W.; Ni, P.; Penn, G.E.; Perkins, L.J.; Qin, H.; Roy, P.K.; Sefkow, A.B.; Seidl, P.A.; Sharp, W.; Startsev, E.A.; Varentsov, D.; Vay, J.-L.; Waldron, W.L.; Wurtele, J.S.; Welch, D.; Westenskow, G.A.; Yu, S.S.

2007-06-25

40

Fusion energy Fusion powers the Sun, and all stars, in which light nuclei fuse together at high temperatures  

E-print Network

Fusion energy · Fusion powers the Sun, and all stars, in which light nuclei fuse together at high in excess of 100 million degrees, much higher than in the Sun. The hot hydrogen gas (known as a `plasma

41

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

42

The binding affinity of a soluble TCR-Fc fusion protein is significantly improved by crosslinkage with an anti-C{beta} antibody  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer A novel soluble TCR composed of TCR V and C regions with Ig Fc region is generated. Black-Right-Pointing-Pointer TCR-Fc protein immobilized by an anti-C{beta} antibody bound to a p/MHC tetramer. Black-Right-Pointing-Pointer Binding affinity of TCR-Fc was markedly increased by binding with anti-C{beta} antibody. -- Abstract: The identification and cloning of tumor antigen-specific T cell receptors (TCRs) and the production of the soluble form of the TCR (sTCR) contributed to the development of diagnostic and therapeutic tools for cancer. Recently, several groups have reported the development of technologies for the production of sTCRs. The native sTCR has a very low binding affinity for the antigenic peptide/MHC (p/MHC) complex. In this study, we established a technology to produce high affinity, functional sTCRs. We generated a novel sTCR-Fc fusion protein composed of the TCR V and C regions of the TCR linked to the immunoglobulin (Ig) Fc region. A Western blot analysis revealed that the molecular weight of the fusion protein was approximately 60 kDa under reducing conditions and approximately 100-200 kDa under non-reducing conditions. ELISAs using various antibodies showed that the structure of each domain of the TCR-Fc protein was intact. The TCR-Fc protein immobilized by an anti-C{beta} antibody effectively bound to a p/MHC tetramer. An SPR analysis showed that the TCR-Fc protein had a low binding affinity (KD; 1.1 Multiplication-Sign 10{sup -5} M) to the p/MHC monomer. Interestingly, when the TCR-Fc protein was pre-incubated with an anti-C{beta} antibody, its binding affinity for p/MHC increased by 5-fold (2.2 Multiplication-Sign 10{sup -6} M). We demonstrated a novel method for constructing a functional soluble TCR using the Ig Fc region and showed that the binding affinity of the functional sTCR-Fc was markedly increased by an anti-C{beta} antibody, which is probably due to the stabilization of the V{alpha}/V{beta} region of the TCR. These findings provide new insights into the binding of sTCRs to p/MHCs and will hopefully be instrumental in establishing functional sTCR as a diagnostic and therapeutic tool for cancer.

Ozawa, Tatsuhiko; Horii, Masae; Kobayashi, Eiji [Department of Immunology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194 (Japan)] [Department of Immunology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194 (Japan); Jin, Aishun [Department of Immunology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194 (Japan) [Department of Immunology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194 (Japan); Department of Immunology, College of Basic Medical Sciences, Harbin Medical University, 157 Baojian Road, Nangang District, Harbin 150081 (China); Kishi, Hiroyuki, E-mail: immkishi@med.u-toyama.ac.jp [Department of Immunology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194 (Japan)] [Department of Immunology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194 (Japan); Muraguchi, Atsushi [Department of Immunology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194 (Japan)] [Department of Immunology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194 (Japan)

2012-06-01

43

Filipino beta zero thalassaemia: a high Hb A2 beta zero thalassaemia resulting from a large deletion of the 5' beta globin gene region.  

PubMed Central

A large novel deletional beta zero thalassaemia mutation associated with unusually high levels of haemoglobin (Hb) A2 in heterozygotes is described in two unrelated subjects of Filipino background. The deletion was characterised by DNA mapping including pulsed field gel electrophoresis. Filipino beta zero thalassaemia extends for approximately 45 kb beginning approximately 1.5 kb 3' to the delta globin gene. It is the largest deletion to date which gives rise to the beta zero thalassaemia phenotype. This mutation, similar to previously described deletional beta zero thalassaemias associated with high Hb A2, removes sequences 5' to the beta globin gene promoter and emphasises the functional importance of the 5' beta globin region in eliciting the unusually high level of Hb A2. This example also suggests that it is the 3' sequences which are transposed rather than the actual deletion size which are significant in the raised fetal haemoglobin (Hb F) found with some of the thalassaemias. Images PMID:7682618

Motum, P I; Kearney, A; Hamilton, T J; Trent, R J

1993-01-01

44

High-temperature plasmas in a tokamak fusion test reactor  

Microsoft Academic Search

Neutral-beam heating of plasmas in the Tokamak Fusion Test Reactor at low preinjection densities (n\\/sub e\\/(0)approx. =10¹⁹ m⁻³) were characterized by T\\/sub e\\/(0) = 6.5 keV, T\\/sub i\\/(0) = 20 keV, n\\/sub e\\/(0) = 7 x 10¹⁹ m⁻³, tau\\/sub E\\/ = 170 msec, ..beta..\\/sub t\\/\\/sub h\\/\\/sub e\\/\\/sub t\\/\\/sub a\\/ = 2, and a d(d,n)³He neutron emission rate of 10¹⁶ sec⁻¹.

J. D. Strachan; M. Bitter; A. T. Ramsey; M. C. Zarnstorff; V. Arunasalam; M. G. Bell; N. L. Bretz; R. Budny; C. E. Bush; S. L. Davis; P. Efthimion; R. Fonck; E. Fredrickson; H. Furth; R. Goldston; L. Grisham; B. Grek; R. Hawryluk; W. Heidbrink; H. Hendel; K. Hill; H. Hsuan; K. Jaehnig; D. Jassby; F. Jobes; D. Johnson; L. Johnson; R. Kaita; J. Kampershroer; R. Knize; T. Kozub; B. LeBlanc; F. Levinton; P. La Marche; D. Manos; D. Mansfield; K. McGuire; D. McNeill; D. Meade; S. Medley; W. Morris; D. Mueller; E. Nieschmidt; D. Owens; J. Schivell; G. Schilling; G. Schmidt; S. Scott; S. Sesnic; J. Sinnis; F. Stauffer; B. Stratton; G. Tait; G. Taylor; H. Towner; M. Ulrickson; S. von Goeler; R. Wieland; M. Williams; K. L. Wong; S. Yoshikawa; K. Young; S. Zweben

1987-01-01

45

Quasi-isodynamic Configuration With N = 12 and High {beta}  

SciTech Connect

Results of an optimization toward quasi-isodynamicity for a stellarator with a comparatively large number of periods, N = 12, are presented. The following set of physics properties to be achieved was used: 1) good long-time collisionless confinement of {alpha}-particles; 2) small neoclassical transport in the 1/{nu} regime; 3) small bootstrap current; 4) high stability-{beta} limit. As a result, the boundary magnetic surface of a configuration is found that satisfies the above requirements for <{beta}> {approx_equal} 20%.

Mikhailov, M. I.; Isaev, M. Yu.; Subbotin, A. A.; Shafranov, V. D. [Russian Research Centre 'Kurchatov Institute', Moscow (Russian Federation); Nuehrenberg, C.; Nuehrenberg, J.; Zille, R. [Max-Planck-Institut fuer Plasmaphysik, IPP-EURATOM Association (Germany); Cooper, A. [CRPP, Association Euratom-Confederation Suisse, EPFL, Lausanne (Switzerland)

2006-11-30

46

High-gain volume ignition for inertial confinement fusion (ICF)  

Microsoft Academic Search

Since 1976, volume ignition calculations of pellet-fueled inertial confinement fusion have shown very high fusion gains due to the strong temperature increases caused by self-heating. This phenomenon was first reported in 1978 (Hora & Ray) and subsequently named the Wheeler modes. The very low optimum initial temperatures (≊1 keV) and the fuel burn of up to 80% permit gains of

H. Hora; S. Eliezer; J. M. Martinez-Val; G. H. Miley

1994-01-01

47

An EMD-IHS model for high resolution image fusion  

Microsoft Academic Search

High resolution image fusion is a significant focus in the field of the image processing. A new image fusion model is presented based on the characteristic level of Empirical Mode Decomposition (EMD). The IHS transform of the multi-spectral image firstly gives the intensity image. Thereafter, the 2D EMD in terms of row-column extension of the 1D EMD model was used

Jian Wang; Changhui Xu; Jixian Zhang; Zhengjun Liu

2007-01-01

48

Galectin-1 as a fusion partner for the production of soluble and folded human {beta}-1,4-galactosyltransferase-T7 in E. coli  

SciTech Connect

The expression of recombinant proteins in Escherichia coli often leads to inactive aggregated proteins known as the inclusion bodies. To date, the best available tool has been the use of fusion tags, including the carbohydrate-binding protein; e.g., the maltose-binding protein (MBP) that enhances the solubility of recombinant proteins. However, none of these fusion tags work universally with every partner protein. We hypothesized that galectins, which are also carbohydrate-binding proteins, may help as fusion partners in folding the mammalian proteins in E. coli. Here we show for the first time that a small soluble lectin, human galectin-1, one member of a large galectin family, can function as a fusion partner to produce soluble folded recombinant human glycosyltransferase, {beta}-1,4-galactosyltransferase-7 ({beta}4Gal-T7), in E. coli. The enzyme {beta}4Gal-T7 transfers galactose to xylose during the synthesis of the tetrasaccharide linker sequence attached to a Ser residue of proteoglycans. Without a fusion partner, {beta}4Gal-T7 is expressed in E. coli as inclusion bodies. We have designed a new vector construct, pLgals1, from pET-23a that includes the sequence for human galectin-1, followed by the Tev protease cleavage site, a 6x His-coding sequence, and a multi-cloning site where a cloned gene is inserted. After lactose affinity column purification of galectin-1-{beta}4Gal-T7 fusion protein, the unique protease cleavage site allows the protein {beta}4Gal-T7 to be cleaved from galectin-1 that binds and elutes from UDP-agarose column. The eluted protein is enzymatically active, and shows CD spectra comparable to the folded {beta}4Gal-T1. The engineered galectin-1 vector could prove to be a valuable tool for expressing other proteins in E. coli.

Pasek, Marta [Structural Glycobiology Section, SAIC-Frederick, Inc., Center for Cancer Research Nanobiology Program, Center for Cancer Research, NCI-Frederick, Frederick, MD 2170 (United States)] [Structural Glycobiology Section, SAIC-Frederick, Inc., Center for Cancer Research Nanobiology Program, Center for Cancer Research, NCI-Frederick, Frederick, MD 2170 (United States); Boeggeman, Elizabeth; Ramakrishnan, Boopathy [Structural Glycobiology Section, SAIC-Frederick, Inc., Center for Cancer Research Nanobiology Program, Center for Cancer Research, NCI-Frederick, Frederick, MD 2170 (United States) [Structural Glycobiology Section, SAIC-Frederick, Inc., Center for Cancer Research Nanobiology Program, Center for Cancer Research, NCI-Frederick, Frederick, MD 2170 (United States); Basic Science Program, SAIC-Frederick, Inc., Center for Cancer Research Nanobiology Program, Center for Cancer Research, NCI-Frederick, Frederick, MD 2170 (United States); Qasba, Pradman K., E-mail: qasba@helix.nih.gov [Structural Glycobiology Section, SAIC-Frederick, Inc., Center for Cancer Research Nanobiology Program, Center for Cancer Research, NCI-Frederick, Frederick, MD 2170 (United States)

2010-04-09

49

The Beta Pictoris circumstellar disk. XV - Highly ionized species near Beta Pictoris  

NASA Technical Reports Server (NTRS)

Temporal variations of the Fe II, Mg II, and Al III circumstellar lines towards Beta Pictoris have been detected and monitored since 1985. However, the unusual presence of Al III ions is still puzzling, since the UV stellar flux from an A5V star such as Beta Pic is insufficient to produce such an ion. In order to better define the origin of such a phenomenon, new observations have been carried out to detect faint signatures of other highly ionized species in the short UV wavelength range, where the stellar continuum flux is low. These observations reveal variations not only near the C IV doublet lines, but also in C I and Al II lines, two weakly ionized species, not clearly detectable until now. In the framework of an infalling body scenario, highly ionized species would be created in the tail, far from the comet head, by collisions with ambient gas surrounding the star, or a weak stellar wind. Spectral changes have also been detected near a CO molecular band location, which, if confirmed, would provide the first molecular signature around Beta Pictoris.

Deleuil, M.; Gry, C.; Lagrange-Henri, A.-M.; Vidal-Madjar, A.; Beust, H.; Ferlet, R.; Moos, H. W.; Livengood, T. A.; Ziskin, D.; Feldman, P. D.

1993-01-01

50

Towards fusion technique for astronomical images with high dynamic range  

NASA Astrophysics Data System (ADS)

Astronomical detection always need high dynamic range image, but there are problems such as underexposure or overexposure in astronomical images taken by commercial camera, this paper proposed the technique that combine establishing the first order difference quotient curve of each pixel with data feature positioning to calculate optimal exposure value of each pixel, which achieves high dynamic range fusion. In this paper, data feature positioning method was firstly utilized to establish mathematical model to calculate optimal exposure point in the first order difference quotient curve of each pixel in the target scene. Correlate optimal exposure point and camera response function to calculate optimal brightness value of each pixel, the fused high dynamic range image will be achieved. Finally, take a series of low dynamic range images with different exposure value by commercial camera, establish mathematical model and calculate to achieve high dynamic range fusion, which verifies the fusion technique proposed in this paper can obtain high dynamic range astronomical images effectively.

Du, Lin; Sun, Huayan; Hou, Zhaofei; Qi, Yingying

2014-08-01

51

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

52

CC CKR5: A RANTES, MIP1alpha, MIP1beta Receptor as a Fusion Cofactor for Macrophage-Tropic HIV1  

Microsoft Academic Search

Human immunodeficiency virus-type 1 (HIV-1) entry requires fusion cofactors on the CD4^+ target cell. Fusin, a heterotrimeric GTP-binding protein (G protein)-coupled receptor, serves as a cofactor for T cell line-tropic isolates. The chemokines RANTES, MIP-1alpha, and MIP-1beta, which suppress infection by macrophage-tropic isolates, selectively inhibited cell fusion mediated by the corresponding envelope glycoproteins (Envs). Recombinant CC CKR5, a G protein-coupled

Ghalib Alkhatib; Christophe Combadiere; Christopher C. Broder; Yu Feng; Paul E. Kennedy; Philip M. Murphy; Edward A. Berger

1996-01-01

53

Reactivity of V beta 17a+ CD8+ T cell hybrids. Analysis using a new CD8+ T cell fusion partner  

PubMed Central

Tolerance to IE molecules leads to deletion of V beta 17a-bearing T cells. Both, the CD4+ as well as the CD8+ T cell subsets are affected. A large percentage of CD4+ V beta 17a+ T cell hybrids recognize IE molecules. We now have investigated the reactivity for IE antigens of CD8+ V beta 17a+ T cell hybrids. Using a transfection approach, we have introduced the murine CD8 molecule into different V beta 17a+ T cell hybrids. Furthermore, the CD8 cDNA was transfected into the BW5147 alpha-beta- fusion partner. This allowed us to generate a large number of V beta 17a+ T cell hybrids by fusion with the appropriate T cells. Only 6% of T cell hybrids were stimulated to produce IL-2 upon incubation with IE+ cells. However, in those, the CD8 molecule seemed not to contribute to the IE reactivity of the hybrid, since mAbs against the CD8 molecule failed to inhibit their reactivity. This low percentage of V beta 17a+ CD8+ IE-reactive T cell hybrids contrasts with the strong reduction of CD8+ V beta 17a+ T cells in IE+ mice, strongly suggesting that elimination of such cells in the thymus occurs when they are coexpressing CD4 and CD8. This view was confirmed by the occasional expression of CD4 in some hybrids in which case IE reactivity was detected. Furthermore, we demonstrated the functional integrity of the introduced CD8 molecule by: (a) reconstitution of the IL-2 response in a class I-restricted TNP-specific T cell hybrid; and (b) by generation of alloreactive class I-restricted T cell hybrids using the new CD8+ fusion cell line. This CD8+ fusion partner, BWLyt2- 4, should prove useful to study antigen processing and antigen presentation requirements of class I-restricted T cells. PMID:2511267

1989-01-01

54

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

55

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

56

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

57

RWM Stabilization to Sustain High Normalized Beta at Low Internal Inductance in NSTX^*  

NASA Astrophysics Data System (ADS)

Spherical torus fusion applications aim to operate at high normalized beta, ?N, and non-inductive current fraction. These plasmas exhibit broad current profiles and low plasma internal inductance, li. In NSTX, such plasmas show a significant reduction of the ideal n = 1 no-wall stability limit at 0.4 < li< 0.6. High ?N> 6 is reached, exceeding the ideal limit by a factor of two. Plasmas below this li range are computed to be near the current- driven ideal kink stability limit, where mode stabilization is required at finite beta. Two active control approaches are used: (i) combined use of radial and poloidal field resistive wall mode (RWM) sensors with n = 1 proportional gain feedback and (ii) an RWM state-space controller including an unstable RWM eigenfunction model and currents induced in nearby 3D conducting structure. Long-pulse plasmas reached ?N/ li> 13. Disruption probability was significantly reduced in plasmas at high ?N/li> 11 with more disruptions seen at lower ?N/li consistent with theory showing decreased passive RWM stabilization at intermediate plasma rotation levels. New independent control of the six actuator coils will allow the RWM state space controller to produce mode control field spectra with n > 1. ^*Work supported by U.S. DOE Contracts DE-FG02-99ER54524 and DE-AC02-09CH11466.

Berkery, J. W.; Sabbagh, S. A.; Bialek, J. M.; Katsuro-Hopkins, O.; Bell, R. E.; Gerhardt, S. P.; Leblanc, B. P.; Tritz, K.

2011-11-01

58

Super-X divertors and high power density fusion devices  

SciTech Connect

The Super-X Divertor (SXD), a robust axisymmetric redesign of the divertor magnetic geometry that can allow a fivefold increase in the core power density of toroidal fusion devices, is presented. With small changes in poloidal coils and currents for standard divertors, the SXD allows the largest divertor plate radius inside toroidal field coils. This increases the plasma-wetted area by 2-3 times over all flux-expansion-only methods (e.g., plate near main X point, plate tilting, X divertor, and snowflake), decreases parallel heat flux and hence plasma temperature at plate, and increases connection length by 2-5 times. Examples of high-power-density fusion devices enabled by SXD are discussed; the most promising near-term device is a 100 MW modular compact fusion neutron source 'battery' small enough to fit inside a conventional fission blanket.

Valanju, P. M.; Kotschenreuther, M.; Mahajan, S. M. [Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712-1060 (United States); Canik, J. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830 (United States)

2009-05-15

59

Super-X Divertors and High Power Density Fusion Devices  

SciTech Connect

The Super-X Divertor (SXD), a robust axisymmetric redesign of the divertor magnetic geometry that can allow a fivefold increase in the core power density of toroidal fusion devices, is presented. With small changes in poloidal coils and currents for standard divertors, the SXD allows the largest divertor plate radius inside toroidal field coils. This increases the plasma-wetted area by 2-3 times over all flux-expansion-only methods (e.g., plate near main X point, plate tilting, X divertor, and snowflake), decreases parallel heat flux and hence plasma temperature at plate, and increases connection length by 2-5 times. Examples of high-power-density fusion devices enabled by SXD are discussed; the most promising near-term device is a 100 MW modular compact fusion neutron source "battery" small enough to fit inside a conventional fission blanket.

Valanju, P. [University of Texas, Austin; Kotschenreuther, M. [University of Texas, Austin; Mahajan, S. [University of Texas, Austin; Canik, John [ORNL

2009-01-01

60

1. INTRODUCTION High-energy fusion-product (fp) transport (e.g., alpha particle  

E-print Network

-T plasmas) is a central issue in fusion reactor de- velopment. Important effects dependent on fp transport by energetic, charged fusion products is a crucial issue for obtaining fusion reactor conditions. The evolution1 1. INTRODUCTION High-energy fusion-product (fp) transport (e.g., alpha particle transport in D

Hively, Lee M.

61

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 Alfvnic 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

62

Fully electromagnetic gyrokinetic eigenmode analysis of high-beta shaped plasmas  

SciTech Connect

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 Alfvenic 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 {delta}B{sub ||} of the perturbation.

Belli, E. A.; Candy, J. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States)

2010-11-15

63

Fusion blanket high-temperature heat transfer  

SciTech Connect

Deep penetration of 14 MeV neutrons makes two-temperature region blankets feasible. A relatively low-temperature (approx. 300/sup 0/C) metallic structure is the vacuum/coolant pressure boundary, while the interior of the blanket, which is a simple packed bed of nonstructural material, operates at very high temperatures (>1000/sup 0/C). The water-cooled shell structure is thermally insulated from the steam-cooled interior. High-temperature steam can dramatically increase the efficiency of electric power generation, as well as produce hydrogen and oxygen-based synthetic fuels at high-efficiency.

Fillo, J.A.

1983-01-01

64

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

65

Blanket options for high-efficiency fusion power  

SciTech Connect

The efficiencies of blankets for fusion reactors are usually in the range of 30 to 40%, limited by the operating temperatures (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 argon) utilizing Li/sub 2/O for tritium breeding. In this design, approximately 60% of the fusion energy is deposited in the high-temperature interior. The maximum argon temperature is 2230/sup 0/C leading to an overall efficiency estimate of 55 to 60% for this reference case.

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

1980-01-01

66

High temperature superconducting current leads for fusion magnet systems  

NASA Astrophysics Data System (ADS)

Superconducting magnets for fusion applications typically have very high operating currents. These currents are transmitted from the room temperature power supplies to the low temperature superconducting coils by way of helium-vapor-cooled current leads. Because of the high current magnitude and the resistive characteristics associated with the normal metallic lead conductors, a substantial amount of power is dissipated in the lead. To maintain a stable operation, a high rate of helium vapor flow, generated by the boil-off of liquid helium, is required to cool the lead conductors. This helium boil-off substantially increases both the installation capacity and the operating cost of the helium refrigerator/liquefier. The boil-off of liquid helium can be significantly reduced by employing ceramic high temperature superconductors, such as Y-Ba-Cu-O, in the low temperature part of the lead conductor structure. This concept utilizes the superconducting, as well as the low thermal conductivity properties of the superconductor materials in eliminating power dissipation in part of the current lead and in inhibiting heat conduction into the liquid helium pool, resulting in reduced helium boil-off. This design concept has been conclusively demonstrated by a 2-kA current lead test model using Y-Ba-Cu-O (123) material which, although not optimized in design, has significantly reduced the rate of helium boil-off in comparison to optimized conventional leads. There appear to be no major technological barriers for scaling up this design to higher current levels for applications in fusion magnet systems or in fusion related testing activities. The theoretical basis of the current lead concept, as well as the important design and technology issues are addressed. The potential cost saving derived from employing these leads in fusion magnets is also discussed. In addition, a design concept for a 10-kA lead is presented.

Wu, J. L.; Dederer, J. T.; Singh, S. K.; Hull, J. R.

67

Human fat cell beta-adrenergic receptors: beta-agonist-dependent lipolytic responses and characterization of beta-adrenergic binding sites on human fat cell membranes with highly selective beta 1-antagonists.  

PubMed

Beta-adrenergic receptors were characterized in human fat cell membranes using 125I-labeled cyanopindolol (125I-labeled CYP) and highly selective beta 1-antagonists. The iodinated radioligand bound saturably and specifically to a single class of high affinity binding sites. The number of binding sites determined with 125I-labeled CYP closely agreed with that determined with two other tritiated radioligands: [3H]dihydroalprenolol and [3H]CGP-12,177. Since 125I-labeled CYP does not discriminate between beta 1- and beta 2-adrenoceptors, the densities of the two receptor subtypes were determined from the competition curves of 125I-labeled CYP by highly selective beta 1-antagonists (bisoprolol, ICI-89,406, CGP-20,712A, and LK-204,545). Moreover, in order to enable correlation with binding data, the regulation of adenylate cyclase activity and of lipolysis was tested with various beta-agonist and antagonist compounds. The results obtained on fat cell membranes from abdominal subcutaneous adipose tissue demonstrated the following. 1) 125I-labeled CYP represents a valuable tool for the quantification and the delineation of beta-receptor subtypes. 2) The presence of sodium ions in binding buffers causes a modification of the affinity of beta-sites for some beta-antagonists. 3) The human fat cell beta adrenergic receptor population defined by nonselective radioligands is composed of two subtypes that can be interpreted in terms of classic beta 1- and beta 2-adrenergic receptor subtypes as assessed by competition studies with highly selective antagonists; beta 2-sites are predominant (60-70% of 125I-labeled CYP sites) in the adipocytes of slightly overweight women. 4) Results support the idea that beta 1- as well as beta 2-adrenergic receptors are coupled with adenylate cyclase and involved in the induction of lipolysis. 5) The results focus on the interest in some beta 2-agonist drugs (zinterol, clenbuterol) as partial inductors of lipolysis, with the lipolytic efficacies of these compounds being well correlated with their efficacies at 125I-labeled CYP sites. PMID:2900871

Maurige, P; De Pergola, G; Berlan, M; Lafontan, M

1988-05-01

68

High-Energy Space Propulsion Based on Magnetized Target Fusion  

NASA Technical Reports Server (NTRS)

Magnetized target fusion is an approach in which a magnetized target plasma is compressed inertially by an imploding material wall. A high energy plasma liner may be used to produce the required implosion. The plasma liner is formed by the merging of a number of high momentum plasma jets converging towards the center of a sphere where two compact toroids have been introduced. Preliminary 3-D hydrodynamics modeling results using the SPHINX code of Los Alamos National Laboratory have been very encouraging and confirm earlier theoretical expectations. The concept appears ready for experimental exploration and plans for doing so are being pursued. In this talk, we explore conceptually how this innovative fusion approach could be packaged for space propulsion for interplanetary travel. We discuss the generally generic components of a baseline propulsion concept including the fusion engine, high velocity plasma accelerators, generators of compact toroids using conical theta pinches, magnetic nozzle, neutron absorption blanket, tritium reprocessing system, shock absorber, magnetohydrodynamic generator, capacitor pulsed power system, thermal management system, and micrometeorite shields.

Thio, Y. C. F.; Landrum, D. B.; Freeze, B.; Kirkpatrick, R. C.; Gerrish, H.; Schmidt, G. R.

1999-01-01

69

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

70

High-Yield Magnetized Liner Fusion Explosions and Blast Mitigation  

NASA Astrophysics Data System (ADS)

Cylindrical liner implosions with preheated and magnetized deuterium-tritium (DT) are predicted to reach fusion conditions on present pulsed power machines [S.A. Slutz et al Phys. Plasmas 17, 056303 (2010)]. We present simulations indicating that high yields (1-10 GJ) and gains (100-1000) may be possible at currents of about 60-70 MA if a cryogenic layer of solid DT is provided on the inside surface of the metal liner. A hot spot is formed from the central preheated magnetized low-density gas and a burn wave propagates radially into the surrounding cold dense fuel. These yields and gains are more than adequate for inertial fusion energy. However, the pulsed-power driver must be protected from the blast of these high-yield explosions. Numerical simulations are presented which show that the blast can be deflected and the fusion neutrons absorbed by a blanket that partially surrounds the liner. Thus a modest length transmission line can be used to deliver power to the liner.

Slutz, Stephen; Vesey, Roger; Cuneo, Michael

2011-11-01

71

Fusion reactor high vacuum pumping: Charcoal cryosorber tritium exposure results  

SciTech Connect

Recent experiments, have shown the practically of using activated charcoal (coconut charcoal) at 4{degrees}K to pump helium and hydrogen isotopes for a fusion reactor. Both speed and capacity for deuterium/helium and tritium/helium-3 mixtures were shown to be satisfactory. The long term effects of tritium on the charcoal/cement system developed by Grumman and LLNL were not known and a program was undertaken to see what, if any, effect long term tritium exposure has on the cryosorber. Several charcoal on aluminum test samples were subjected to six months exposure of tritium at approximately 77{degrees}K. The tritium was scanned several times with a residual gas analyzer and the speed-capacity performance of the samples was measured before, approximately half way through and after the exposure. Modest effects were noted which would not seriously restrict charcoal's use as a cryosorber for fusion reactor high vacuum pumping applications. 4 refs., 8 figs.

Sedgley, D.W.; Walthers, C.R.; Jenkins, E.M. (Grumman Aerospace Corp., Bethpage, NY (United States))

1991-01-01

72

High Frequency of Fusion Transcripts Involving TCF7L2 in Colorectal Cancer: Novel Fusion Partner and Splice Variants  

PubMed Central

VTI1A-TCF7L2 was reported as a recurrent fusion gene in colorectal cancer (CRC), found to be expressed in three out of 97 primary cancers, and one cell line, NCI-H508, where a genomic deletion joins the two genes [1]. To investigate this fusion further, we analyzed high-throughput DNA and RNA sequencing data from seven CRC cell lines, and identified the gene RP11-57H14.3 (ENSG00000225292) as a novel fusion partner for TCF7L2. The fusion was discovered from both genome and transcriptome data in the HCT116 cell line. By triplicate nested RT-PCR, we tested both the novel fusion transcript and VTI1A-TCF7L2 for expression in a series of 106 CRC tissues, 21 CRC cell lines, 14 normal colonic mucosa, and 20 normal tissues from miscellaneous anatomical sites. Altogether, 42% and 45% of the CRC samples expressed VTI1A-TCF7L2 and TCF7L2-RP11-57H14.3 fusion transcripts, respectively. The fusion transcripts were both seen in 29% of the normal colonic mucosa samples, and in 25% and 75% of the tested normal tissues from other organs, revealing that the TCF7L2 fusion transcripts are neither specific to cancer nor to the colon and rectum. Seven different splice variants were detected for the VTI1A-TCF7L2 fusion, of which three are novel. Four different splice variants were detected for the TCF7L2-RP11-57H14.3 fusion. In conclusion, we have identified novel variants of VTI1A-TCF7L2 fusion transcripts, including a novel fusion partner gene, RP11-57H14.3, and demonstrated detectable levels in a large fraction of CRC samples, as well as in normal colonic mucosa and other tissue types. We suggest that the fusion transcripts observed in a high frequency of samples are transcription induced chimeras that are expressed at low levels in most samples. The similar fusion transcripts induced by genomic rearrangements observed in individual cancer cell lines may yet have oncogenic potential as suggested in the original study by Bass et al. PMID:24608966

Bakken, Anne Cathrine; Rognum, Torleiv O.; Nesbakken, Arild; Skotheim, Rolf I.

2014-01-01

73

High-gain inertial confinement fusion by volume ignition, avoiding the complexities of fusion detonation fronts of spark ignition  

Microsoft Academic Search

Summary form only given, as follows. The main approach to inertial confinement fusion (ICF) uses a high-temperature, low-density core and a high-density, low-temperature outer region of the laser(or ion beam-) compressed deuterium-tritium (D-T) fuel, in order to ignite a fusion detonation wave at the interface. This is an extremely delicate, unstable configuration which is very difficult to achieve, even with

H. Hora; S. Eliezer; J. J. Honrubia; R. Hopfl; J. M. Martinez-Val; G. H. Miley; G. Velarde

1995-01-01

74

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. PMID:19838344

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

2009-01-01

75

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

76

High Current Ion Source Development for Heavy Ion Fusion  

SciTech Connect

We are developing high-current-density high-brightness sources for Heavy Ion Fusion applications. Heavy ion driven inertial fusion requires beams of high brightness in order to achieve high power density at the target for high target gain. At present, there are no existing ion source types that can readily meet all the driver HIF requirements, though sources exist which are adequate for present experiments and which with further development may achieve driver requirements. Our two major efforts have been on alumino-silicate sources and RF plasma sources. Experiments being performed on a 10-cm alumino-silicate source are described. To obtain a compact system for a HIF driver we are studying RF plasma sources where low current beamlets are combined to produce a high current beam. A 80-kV 20-{micro}s source has produced up to 5 mA of Ar{sup +} in a single beamlet. The extraction current density was 100 mA/cm{sup 2}. We present measurements of the extracted current density as a function of RF power and gas pressure, current density uniformity, emittance, and energy dispersion (due to charge exchange).

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

2003-09-04

77

Effects of high density lipoprotein containing high or low beta-carotene concentrations on progesterone production and beta-carotene uptake and depletion by bovine luteal cells.  

PubMed

Luteal cells were isolated from mid-luteal heifer ovaries by collagenase digestion. Cells were cultured with DMEM/Ham's F12 medium in serum pre-treated plastic culture dishes for periods of up to 11 days. As beta-carotene is almost completely insoluble in all polar solvents, it was added to cultures in either dimethyl sulphoxide (DMSO), tetrahydrofuran (THF) or as high-density lipoprotein (HDL) containing high or low beta-carotene concentrations. Medium was replaced after 24 h, thereafter medium was changed every 48 h. Treatment of cells with DMSO alone or with beta-carotene (5 micromol/l) in DMSO both resulted in significant (P<0.01) stimulation of progesterone production. beta-Carotene (5 micromol/l) in THF did not alter progesterone production but 50 micromol/l beta-carotene in THF resulted in significant inhibition (P<0.02) of progesterone production on days 3 and 7. Cultures were also supplemented with bovine HDL preparations containing equal concentrations of cholesterol (25 microg/ml) but high or low beta-carotene (12.4 or 0.44 microg/mg of cholesterol). Both HDL preparations significantly stimulated progesterone production (P<0. 001) but the high beta-carotene HDL was significantly (P<0.02) more effective than the low beta-carotene HDL. However, when given together with bovine luteinizing hormone (bLH) or dibutyryl cAMP (dbcAMP), the high beta-carotene HDL stimulated progesterone production less than did the low HDL (P<0.01). Uptake and depletion of beta-carotene by luteal cells were also examined in culture. beta-Carotene supplementation increased luteal cell beta-carotene from an initial level of 373 ng per 10(6) cells to 2030 ng per 10(6) cells by day 6. In contrast, the levels in control cells decreased to 14% of starting values during the same period. Cells treated with HDL containing high beta-carotene on day 1 or days 1 and 3 were then incubated with or without bLH or dbcAMP for a further 2 days to investigate the effect of bLH and dbcAMP on depletion of beta-carotene by luteal cells. beta-Carotene depletion in the luteal cells was significantly higher (P<0.05) in LH- and dbcAMP-treated cells than in the control cells in both groups. These results indicate that the use of solvents such as DMSO or THF may have undesirable effects due to alteration of cell membrane permeability. Supplementation with bLH or dbcAMP may increase the metabolism of beta-carotene in luteal cells. bLH or dbcAMP together with high beta-carotene HDL may, when combined with the effect of increased beta-carotene metabolism, give less stimulation than with low beta-carotene HDL. PMID:10924828

Arikan, S; Rodway, R G

2000-09-01

78

Energy scaling of inertial confinement fusion targets for ignition and high gain  

Microsoft Academic Search

The dependence of the ignition threshold on the velocity vimp and compressibility of an imploding fuel mass is central to establishing the driver requirements and implosion strategy for inertial confinement fusion (ICF). Using a series of LASNEX calculations, it is found that keimp varies as nu imp- alpha beta a, where keimp is the kinetic energy in the imploding fuel

W. K. Levedahl; J. D. Lindl

1997-01-01

79

Ignitor and the High Density Approach for Fusion*  

NASA Astrophysics Data System (ADS)

The high plasma density regimes discovered by high magnetic field toroidal experiments have both outstanding confinement characteristics and degree of purity, and are at the basis of the Ignitor design. The main purpose of the Ignitor experiment is, in fact, that of establishing the reactor physics in regimes close to ignition, where the thermonuclear instability can set in with all its associated non linear effects. ``Extended limiter'' and double X-point configurations have been analyzed and relevant transport simulations show that similar burning plasma conditions can be attained with both, by Ohmic heating only or with modest amounts of ICRH auxiliary heating. The driving factor for the machine design (R01.32 m, a xb0.47x0.83 m^2, BT<=13 T, Ip<=11 MA) is the poloidal field pressure that can contain, under macroscopically stable conditions, the peak plasma pressures corresponding to ignition. Objectives other than ignition can be envisioned for the relatively near term, for example that of high flux neutron sources for material testing involving compact, high density fusion machines. This has been one of the incentives that have led the Ignitor Project to adopt magnesium diboride (MgB2) superconducting cables in the machine design, a first in fusion research. Accordingly, the largest coils (about 5 m diameter) of the machine will be made entirely of MgB2 cables. *Sponsored in part by ENEA of Italy and by the U.S. D.O.E.

Bombarda, F.; Coppi, B.

2010-11-01

80

The Physics of Advanced High-Gain Targets for Inertial Fusion Energy  

Microsoft Academic Search

In ca. 2011-2012, the National Ignition Facility is poised to demonstrate fusion ignition and gain in the laboratory for the first time. This key milestone in the development of inertial confinement fusion (ICF) can be expected to engender interest in the development of inertial fusion energy (IFE) and expanded efforts on a number of advanced targets that may achieve high

L. John Perkins

2010-01-01

81

Simulation of transition dynamics to high confinement in fusion plasmas  

E-print Network

The transition dynamics from the low (L) to the high (H) confinement mode in magnetically confined plasmas is investigated using a first-principles four-field fluid model. Numerical results are in close agreement with measurements from the Experimental Advanced Superconducting Tokamak - EAST. Particularly, the slow transition with an intermediate dithering phase is well reproduced by the numerical solutions. Additionally, the model reproduces the experimentally determined L-H transition power threshold scaling that the ion power threshold increases with increasing particle density. The results hold promise for developing predictive models of the transition, essential for understanding and optimizing future fusion power reactors.

Nielsen, A H; Madsen, J; Naulin, V; Rasmussen, J Juul; Wan, B N

2014-01-01

82

Access to high beta advanced inductive plasmas at low injected torque  

NASA Astrophysics Data System (ADS)

Recent experiments on DIII-D demonstrate that advanced inductive (AI) discharges with high equivalent normalized fusion gain can be accessed and sustained with very low amounts (?1 N m) of externally injected torque, a level of torque that is anticipated to drive a similar amount of rotation as the beams on ITER, via simple consideration of the scaling of the moment of inertia and confinement time. The AI regime is typically characterized by high confinement, and high ?N, allowing the possibility for high performance, high gain operation at reduced plasma current. Discharges achieved ?N ? 3.1 with H98(y,2) ? 1 at q95 ? 4, and are sustained for the maximum duration of the counter neutral beams (NBs). In addition, plasmas using zero net NB torque from the startup all the way through to the high ?N phase have been created. AI discharges are found to become increasingly susceptible to m/n = 2/1 neoclassical tearing modes as the torque is decreased, which if left unmitigated, generally slow and lock, terminating the high performance phase of the discharge. Access is not notably different whether one ramps the torque down at high ?N, or ramps ?N up at low torque. The use of electron cyclotron heating (ECH) and current drive proved to be an effective method of avoiding such modes, enabling stable operation at high beta and low torque, a portion of phase space that has otherwise been inaccessible. Thermal confinement is significantly reduced at low rotation, a result that is reproduced using the TGLF transport model. Although it is thought that stiffness is increased in regions of low magnetic shear, in these AI plasmas, the reduced confinement occurs at radii outside the low shear, and in fact, higher temperature gradients can be found in the low shear region at low rotation. Momentum transport is also larger at low rotation, but a significant intrinsic torque is measured that is consistent with a previous scaling considering the role of the turbulent Reynolds stress and thermal ion orbit loss. Although high normalized fusion performance has been achieved in these discharges, more detailed projections suggest that enhancement in the confinement needs to be realized in order to obtain a low current solution consistent with ITER Q = 10 performance, and this remains a future research challenge.

Solomon, W. M.; Politzer, P. A.; Buttery, R. J.; Holcomb, C. T.; Ferron, J. R.; Garofalo, A. M.; Grierson, B. A.; Hanson, J. M.; In, Y.; Jackson, G. L.; Kinsey, J. E.; La Haye, R. J.; Lanctot, M. J.; Luce, T. C.; Okabayashi, M.; Petty, C. C.; Turco, F.; Welander, A. S.

2013-09-01

83

Relevance of High Density Plasma Regimes for Fusion Reactors*  

NASA Astrophysics Data System (ADS)

High density regimes (with peak values around 10^21 m-3) in magnetically confined plasmas have been observed and investigated within the Alcator program at first, and later within the Frascati Torus program. In particular, record low values of the ion thermal conductivity and high degrees of purity(Zeff1) were achieved when peaked density profiles were produced either spontaneously or by the ignition of pellets. It was recognized early on that the large n? values attainable in these regimes are suitable to achieve ignition conditions in devices such as Ignitor that are feasible with existing technologies. Plasma regimes with similar confinement characteristics have been produced in the LHD machine, characterized by relatively low magnetic fields and a helical configuration, by means of repeated pellet injection techniques. Assuming that the good characteristics of these plasmas can be preserved at the temperatures where ignition can occur, the helical configuration characterizing LHD makes it possible to avoid the need of a steady state current drive system, a problem that remains unsolved for meaningful fusion burn regimes with axisymmetric configurations. Experiments on fusion burning plasmas to be developed in parallel along the high field compact line represented by Ignitor and the helical line represented by LHD are envisioned.*Sponsored in part by ENEA of Italy and by the U.S. D.O.E.

Bombarda, F.; Coppi, B.

2009-05-01

84

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

85

The Dynamics of Flux Tubes in a High Beta Plasma  

E-print Network

We suggest a new model for the structure of a magnetic field embedded high $\\beta$ turbulent plasma, based on the popular notion that the magnetic field will tend to separate into individual flux tubes. We point out that interactions between the flux tubes will be dominated by coherent effects stemming from the turbulent wakes created as the fluid streams by the flux tubes. Balancing the attraction caused by shielding effects with turbulent diffusion we find that flux tubes have typical radii comparable to the local Mach number squared times the large scale eddy length, are arranged in a one dimensional fractal pattern, have a radius of curvature comparable to the largest scale eddies in the turbulence, and have an internal magnetic pressure comparable to the ambient pressure. When the average magnetic energy density is much less than the turbulent energy density the radius, internal magnetic field and curvature scale of the flux tubes will be smaller than these estimates. Realistic resistivity does not alter the macroscopic properties of the fluid or the large scale magnetic field. In either case we show that the Sweet-Parker reconnection rate is much faster than an eddy turnover time. Realistic stellar plasmas are expected to either be in the ideal limit (e.g. the solar photosphere) or the resistive limit (most of the solar convection zone). All current numerical simulations of three dimensional MHD turbulence are in the viscous regime and are inapplicable to stars or accretion disks.

E. T. Vishniac

1994-07-21

86

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

87

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

88

Inertial Confinement Fusion: steady progressInertial Confinement Fusion: steady progress towards ignition and high gaintowards ignition and high gain  

E-print Network

for Theoretical and Experimental Physics, Moscow 20th IAEA Conference on Fusion Energy, November 1­6, 2004Inertial Confinement Fusion: steady progressInertial Confinement Fusion: steady progress towards cold main DT in pressure equilibrium with the hot spark · Laser light creates a "bath" of thermal X

89

The highly divergent alpha- and beta-tubulins from Dictyostelium discoideum are encoded by single genes.  

PubMed

As a step in the characterization of the microtubule system of Dictyostelium discoideum, we have isolated and sequenced full-length cDNA clones that encode the Dictyostelium alpha- and beta-tubulins, as well as the Dictyostelium alpha-tubulin gene. Southern blot analysis suggests that Dictyostelium is unusual in that its genome contains single alpha- and beta-tubulin genes, rather than the multi-gene family common in most eukaryotic organisms. The complete alpha-tubulin cDNA contains 1558 nucleotides, with an open reading frame, that encode a protein of 457 amino acids. The complete beta-tubulin cDNA contains 1572 nucleotides and encodes a protein of 456 amino acids. Analysis of the deduced protein sequences indicates that while there is a significant degree of sequence similarity between the Dictyostelium tubulins and other known tubulins, the Dictyostelium alpha-tubulin displays the greatest sequence divergence yet described. Single alpha- and beta-tubulin transcripts are detected by northern blot analysis during all stages of Dictyostelium development. The highest levels of message accumulate late in germinating spores and vegetative amoebae. Despite changes in alpha- and beta-tubulin mRNA levels, protein levels remain constant throughout development. We have expressed the carboxy-terminal two-thirds of the alpha- and beta-tubulins as trpE fusions in Escherichia coli and used this protein to produce polyclonal antisera specific for the Dictyostelium alpha- and beta-tubulins. These antisera recognize one alpha- and two beta-tubulin spots on western blots of 2-D gels and, by indirect immunofluorescence, both recognize the interphase and mitotic microtubule arrays in vegetative amoebae. PMID:8227212

Trivios-Lagos, L; Ohmachi, T; Albrightson, C; Burns, R G; Ennis, H L; Chisholm, R L

1993-08-01

90

Development and application of nonflammable, high-temperature beta fibers  

NASA Technical Reports Server (NTRS)

Recent advances in fiber technology have contributed to the success of the U.S. space program. The inorganic fiber Beta, developed as a result of efforts begun in the early 1960's and heightened following the January 27, 1967 Apollo fire is unique among inorganic and organic fibers. It has been developed into woven, nonwoven, knitted, braided, coated and printed structures. All of these were used extensively for the Apollo, Skylab, Apollo-Soyuz test project, space shuttle, Spacelab, and satellite programs. In addition to being used successfully in the space program, Beta fibers are being used commercially as firesafe fabrics in homes, hospitals, institutions, public buildings, aircraft, and public transportation, wherever total nonflammability is required. One of the most unique applications of the Beta composite structure is the roofing material for the 80,000-seat Detroit Lion's Silverdome and 5 square miles of the Jeddah International Airport in Saudi Arabia. This fiber has been successfully incorporated into 165 major public construction projects around the globe. The United States alone has used more than 12 million square yards of the material. Beta fiber has been used successfully to date and has a promising future with unlimited potential for both space and commercial application. Efforts are currently underway to improve Beta fiber to meet the requirements of extended service life for the Space Station Freedom, lunar outpost, and Mars exploration missions.

Dawn, Frederic S.

1989-01-01

91

Advantages of High Tolerance Measurements in Fusion Environments Applying Photogrammetry  

SciTech Connect

Photogrammetry, a state-of-the-art technique of metrology employing digital photographs as the vehicle for measurement, has been investigated in the fusion environment. Benefits of this high tolerance methodology include relatively easy deployment for multiple point measurements and deformation/distortion studies. Depending on the equipment used, photogrammetric systems can reach tolerances of 25 microns (0.001 in) to 100 microns (0.004 in) on a 3-meter object. During the fabrication and assembly of the National Compact Stellarator Experiment (NCSX) the primary measurement systems deployed were CAD coordinate-based computer metrology equipment and supporting algorithms such as both interferometer-aided (IFM) and absolute distance measurementbased (ADM) laser trackers, as well as portable Coordinate Measurement Machine (CMM) arms. Photogrammetry was employed at NCSX as a quick and easy tool to monitor coil distortions incurred during welding operations of the machine assembly process and as a way to reduce assembly downtime for metrology processes.

T. Dodson, R. Ellis, C. Priniski, S. Raftopoulos, D. Stevens, M. Viola

2009-02-04

92

High natural fusion rates in a botryllid ascidian  

Microsoft Academic Search

Many benthic colonial invertebrates have the ability to fuse and form chimeras with compatible colonies. Botryllid ascidians\\u000a are model organisms for the study of the evolution of and molecular basis for allorecognition, and fusion rates have been\\u000a determined for different populations and species by random sampling and fusion testing between individuals. However, natural\\u000a fusion rates over time have not been

Erica L. Westerman; Jennifer A. Dijkstra; Larry G. Harris

2009-01-01

93

INSTITUTE OF PHYSICS PUBLISHING and INTERNATIONAL ATOMIC ENERGY AGENCY NUCLEAR FUSION Nucl. Fusion 44 (2004) 10151026 PII: S0029-5515(04)83150-8  

E-print Network

INSTITUTE OF PHYSICS PUBLISHING and INTERNATIONAL ATOMIC ENERGY AGENCY NUCLEAR FUSION Nucl. Fusion. The current drive efficiency and the deposited power are calculated employing plasma parameters that can fusion since they are compact, have high beta, and require no toroidal field [1]. They can be formed

Washington at Seattle, University of

94

NMR characterization of an engineered domain fusion between maltose binding protein and TEM1 beta-lactamase provides insight into its structure and allosteric mechanism.  

PubMed

RG13 is a 72 kDa engineered allosteric enzyme comprised of a fusion between maltose binding protein (MBP) and TEM1 beta-lactamase (BLA) for which maltose is a positive effector of BLA activity. We have used NMR spectroscopy to acquire [(15)N, (1)H]-TROSY-HSQC spectra of RG13 in the presence and absence of maltose. The RG13 chemical shift data was compared to the published chemical shift data of MBP and BLA. The spectra are consistent with the expectation that the individual domain structures of RG13 are substantially conserved from MBP and BLA. Differences in the spectra are consistent with the fusion geometry of MBP and BLA and the maltose-dependent differences in the kinetics of RG13 enzyme activity. In particular, the spectra provide evidence for a maltose-dependent conformational change of a key active site glutamate involved in deacylation of the enzyme-substrate intermediate. PMID:20034108

Wright, Chapman M; Majumdar, Ananya; Tolman, Joel R; Ostermeier, Marc

2010-05-01

95

Numerical Analysis of High-beta Spherical Tokamaks with Varied Elongation  

NASA Astrophysics Data System (ADS)

The effect of plasma elongation on the second-stable spherical tokamak (ST)was numerically studied using the experimentally measuredpressure and current profiles of ultra-high beta STs. The maximum beta of ST over 50% was obtained in the TS-3 ST/CT experimentby applying an external toroidal field to an FRC. It was found that the marginal beta for the ballooning instabilityincreased with the plasma elongation ? of ST. The elongated STs with ? > 2 have the magnetic shear (S) -- pressure gradient(?) profiles located in the second-stable regime for the ballooning mode andthe stability margin increased with ?. The close relation between the absolute minimum-B profile andthe second stability was documented. The effect of elongation on maximum beta was observed to saturatewhen ? exceeded 3, indicating that the optimized elongationfor high-beta STs are located around 2 < ? < 3.

Ogawa, Toru; Kimura, Toshiro; Ono, Yasushi

96

The convergence of analytic high-{beta} equilibrium in a finite aspect ratio tokamak  

SciTech Connect

The characteristics of near-unity-{beta} equilibria are investigated with two codes. CUBE is a multigrid Grad-Shafranov solver [Gourdain et al., J. Comput. Phys. 216, 275 (2006)], and Ophidian was written to compute solutions using analytic unity-{beta} equilibria [Cowley et al., Phys. Fluids B 3, 2066 (1991)]. Results from each method are qualitatively and quantitatively compared across a spectrum of mutually relevant parameters. These comparisons corroborate the theoretical results and provide benchmarks for high-resolution numerical results available from CUBE. Both tools facilitate the exploration of the properties of high-{beta} equilibria, such as a highly diamagnetic plasma and its ramifications for stability and transport.

Neches, R. Y.; Cowley, S. C.; Gourdain, P. A.; Leboeuf, J. N. [Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, California 90095 (United States)

2008-12-15

97

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 32:743750, 2011. 2011 Wiley-Liss, Inc. PMID:21387465

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

98

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

NASA Astrophysics Data System (ADS)

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 this and other exciting and important topics. This work consists of an educational WWW presentation about fusion energy science. It is written by an advanced high school student for other high school students with the assistance of a fusion scientist. Jessica Hicks is a HU CFRT Summer Fusion High School Workshop scholar from Crest Senior High School in North Carolina. She is supported by NASA under its NASA Sharp Plus program. This project is supported by the US DOE OFES.

Hicks, Jessica; Calvin, Mark

1996-11-01

99

High Performance Adaptive Fidelity Algorithms for MultiModality Optic Nerve Head Image Fusion  

Microsoft Academic Search

A high performance adaptive fidelity approach for multi-modality Optic Nerve Head (ONH) image fusion is presented. The new\\u000a image fusion method, which consists of the Adaptive Fidelity Exploratory Algorithm (AFEA) and the Heuristic Optimization Algorithm\\u000a (HOA), is reliable and time efficient. It has achieved an optimal fusion result by giving the visualization of fundus image\\u000a with a maximum angiogram overlay.

Hua Cao; Nathan Brener; Bahram Khoobehi; S. Sitharama Iyengar

100

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

101

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

102

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 intensity (line charge density {approx} 0.2 {micro}C/m) over long pulse durations (4 {micro}s) in alternating gradient focusing lattices of electrostatic or magnetic quadrupoles. This experiment is testing transport issues resulting from nonlinear space-charge effects and collective modes, beam centroid alignment and steering, envelope matching, image charges and focusing field nonlinearities, halo and, electron and gas cloud effects. We present the results for a coasting 1 MeV K{sup +} ion beam transported through ten electrostatic quadrupoles. The measurements cover two different fill factor studies (60% and 80% of the clear aperture radius) for which the transverse phase-space of the beam was characterized in detail, along with beam energy measurements and the first halo measurements. Electrostatic quadrupole transport at high beam fill factor ({approx}80%) is achieved with acceptable emittance growth and beam loss, even though the initial beam distribution is not ideal (but the emittance is low) nor in thermal equilibrium. We achieved good envelope control, and rematching may only be needed every ten lattice periods (at 80% fill factor) in a longer lattice of similar design. We also show that understanding and controlling the time dependence of the envelope parameters is critical to achieving high fill factors, notably because of the injector and matching section dynamics.

Prost, L.R.; Baca, D.; Bieniosek, F.M.; Celata, C.M.; Faltens, A.; Henestroza, E.; Kwan, J.W.; Leitner, M.; Seidl, P.A.; Waldron, W.L.; Cohen, R.; Friedman, A.; Grote, D.; Lund, S.M.; Molvik, A.W.; Morse, E.

2004-05-01

103

High current transport experiment for heavy ion inertial fusion  

NASA Astrophysics Data System (ADS)

The High Current Experiment at Lawrence Berkeley National Laboratory is part of the U.S. 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 intensity (line charge density 0.2 ?C/m) over long pulse durations (4 ?s) in alternating gradient focusing lattices of electrostatic or magnetic quadrupoles. This experiment is testing transport issues resulting from nonlinear space-charge effects and collective modes, beam centroid alignment and steering, envelope matching, image charges and focusing field nonlinearities, halo, and electron and gas cloud effects. We present the results for a coasting 1 MeV K+ ion beam transported through ten electrostatic quadrupoles. The measurements cover two different fill factor studies (60% and 80% of the clear aperture radius) for which the transverse phase space of the beam was characterized in detail, along with beam energy measurements and the first halo measurements. Electrostatic quadrupole transport at high beam fill factor (?80%) is achieved with acceptable emittance growth and beam loss, even though the initial beam distribution is not ideal (but the emittance is low) nor in thermal equilibrium. We achieved good envelope control, and rematching may only be needed every ten lattice periods (at 80% fill factor) in a longer lattice of similar design. We also show that understanding and controlling the time dependence of the envelope parameters is critical to achieving high fill factors, notably because of the injector and matching section dynamics.

Prost, L. R.; Seidl, P. A.; Bieniosek, F. M.; Celata, C. M.; Faltens, A.; Baca, D.; Henestroza, E.; Kwan, J. W.; Leitner, M.; Waldron, W. L.; Cohen, R.; Friedman, A.; Grote, D.; Lund, S. M.; Molvik, A. W.; Morse, E.

2005-02-01

104

High current vacuum arc ion source for heavy ion fusion  

SciTech Connect

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 {approximately}0.5 A current beams with {approximately}20 {micro}s pulse widths and {approximately}10 Hz repetition rates are required. Thermionic sources have been the workhorse for the HIF program to date, but suffer from sloe turn-on, heating problems for large areas, are limited to low (contact) ionization potential elements and offer relatively low ion fluxes with a charge state limited to 1+. Gas injection sources suffer from partial ionization and deleterious neutral gas effects. The above shortcomings of the thermionic ion sources can be overcome by a vacuum arc ion source. The vacuum arc ion source is a good candidate for HIF applications. It is capable of providing ions of various elements and different charge states, in short and long pulse bursts, with low emittance and high beam currents. Under a Phase-I STTR from DOE, the feasibility of the vacuum arc ion source for the HIF applications is investigated. An existing ion source at LBNL was modified to produce {approximately}0.5 A, {approximately}60 keV Gd (A{approximately}158) ion beams. The experimental effort concentrated on beam noise reduction, pulse-to-pulse reproducibility and achieving low beam emittance at 0.5 A ion current level. Details of the source development will be reported.

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

1999-07-01

105

Fusion Engineering and Design 54 (2001) 167180 Options for the use of high temperature superconductor  

E-print Network

-documented physical properties of high temperature superconductors are used in the evaluation. Short-sam- ple wires superconductor in tokamak fusion reactor designs L. Bromberg a, *, M. Tekula b , L.A. El-Guebaly c , R. Miller d temperature superconductors (HTS) in long term tokamak fusion reactors is analyzed in this paper. The well

California at San Diego, University of

106

Physics of Laser Fusion. Volume III. High-Power Pulsed Lasers.  

National Technical Information Service (NTIS)

High-power pulsed lasers can deliver sufficient energy on inertial-confinement fusion (ICF) time scales (0.1 to 10 ns) to heat and compress deuterium-tritium fuel to fusion-reaction conditions. Several laser systems have been examined, including Nd:glass,...

D. Eimerl, E. V. George, J. B. Trenholme, J. F. Holzrichter, W. W. Simmons

1982-01-01

107

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

Microsoft Academic Search

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

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

1990-01-01

108

Inertial Confinement Fusion, High Energy Density Plasmas and an Energy Source on Earth  

E-print Network

Inertial Confinement Fusion, High Energy Density Plasmas and an Energy Source on Earth Max Tabak explosions and breed tritium Driver To heat and compress target to fusion conditions #12;Tabak Snowmass #12;#12;-10 0 10 -10 0 10 20 In laser focused light Focused short pulse laser planar shock ICF

109

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

110

Comparison of electron capture and beta decay rates in high temperature environment in explosion of supernova type II  

NASA Astrophysics Data System (ADS)

It is generally acknowledged that Type II supernova results from the collapse of iron core of a massive star which, at least in some cases, produces a neutron star. At this stage, the neutrinos are produced by neutronization which speeds up as collapse continues. During collapse an outward bound shock wave forms in the matter falling onto the nearly stationary core. The conditions behind the shock at 100 to 200 km are suitable for neutrino heating. This neutrino heating blows a hot bubble above the protoneutron star and is the most important source of energy for Supernova explosion. At this stage, we try to attain the r-process (rapid neutron capture process) path responsible for the production of heavy elements beyond iron, which are otherwise not possible to be formed by fusion reactions. The most interesting evolution occurs as temperature falls from 1010 K to 109 K. At these high temperature conditions, the near critical fluids after fusion reactions transform into the respective atoms by r-process path which on beta decaying produce the ultimate elements of the periodic chart. Another astrophysical parameter needed for our analysis is neutron number density which we take to be greater than 1020 cm^{-3}. With these, at different entropy environments, we assign the neutron binding energy that represents the r-process path in the chart of nuclides. Along the path, the experimental data of observed elements matches our calculated one. It is found that the dynamical timescale of the final collapse is dominated by electron capture on nuclei and not on free protons. It is also found that the beta decay rates are much higher than the corresponding electron capture rates at the same classical condition.

Baruah, Rulee

111

Crystal structures of beta- and gammaretrovirus fusion proteins reveal a role for electrostatic stapling in viral entry.  

PubMed

Membrane fusion is a key step in the life cycle of all envelope viruses, but this process is energetically unfavorable; the transmembrane fusion subunit (TM) of the virion-attached glycoprotein actively catalyzes the membrane merger process. Retroviral glycoproteins are the prototypical system to study pH-independent viral entry. In this study, we determined crystal structures of extramembrane regions of the TMs from Mason-Pfizer monkey virus (MPMV) and xenotropic murine leukemia virus-related virus (XMRV) at 1.7-? and 2.2-? resolution, respectively. The structures are comprised of a trimer of hairpins that is characteristic of class I viral fusion proteins and now completes a structural library of retroviral fusion proteins. Our results allowed us to identify a series of intra- and interchain electrostatic interactions in the heptad repeat and chain reversal regions. Mutagenesis reveals that charge-neutralizing salt bridge mutations significantly destabilize the postfusion six-helix bundle and abrogate retroviral infection, demonstrating that electrostatic stapling of the fusion subunit is essential for viral entry. Our data indicate that salt bridges are a major stabilizing force on the MPMV and XMRV retroviral TMs and likely provide the key energetics for viral and host membrane fusion. PMID:24131724

Aydin, Halil; Cook, Jonathan D; Lee, Jeffrey E

2014-01-01

112

High-resolution crystal structure of an engineered human beta2-adrenergic G protein-coupled receptor.  

PubMed

Heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptors constitute the largest family of eukaryotic signal transduction proteins that communicate across the membrane. We report the crystal structure of a human beta2-adrenergic receptor-T4 lysozyme fusion protein bound to the partial inverse agonist carazolol at 2.4 angstrom resolution. The structure provides a high-resolution view of a human G protein-coupled receptor bound to a diffusible ligand. Ligand-binding site accessibility is enabled by the second extracellular loop, which is held out of the binding cavity by a pair of closely spaced disulfide bridges and a short helical segment within the loop. Cholesterol, a necessary component for crystallization, mediates an intriguing parallel association of receptor molecules in the crystal lattice. Although the location of carazolol in the beta2-adrenergic receptor is very similar to that of retinal in rhodopsin, structural differences in the ligand-binding site and other regions highlight the challenges in using rhodopsin as a template model for this large receptor family. PMID:17962520

Cherezov, Vadim; Rosenbaum, Daniel M; Hanson, Michael A; Rasmussen, Sren G F; Thian, Foon Sun; Kobilka, Tong Sun; Choi, Hee-Jung; Kuhn, Peter; Weis, William I; Kobilka, Brian K; Stevens, Raymond C

2007-11-23

113

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

114

Improved confinement at high density and high beta in the MST  

NASA Astrophysics Data System (ADS)

Improved confinement plasmas in MST are routine using current profile control to reduce tearing instabilities. With pellet injection, the density of these plasmas has been increased to values well above the Greenwald limit. At 0.2 MA, the achieved density exceeds the limit by 50%. At 0.5 MA, an MST-record density of 0.7 x 10^20 m-3 is achieved that exceeds the limit by 10%. While confinement is improved at high density, tearing instabilities are not reduced to the same degree as at lower density. This may be due to the larger beta at high density, with total beta reaching 26%. The central pressure gradient violates the Mercier criterion, and linear stability calculations indicate that pressure-driven tearing could be important. The maximum MST energy confinement time of 12 ms, achieved at well below the density limit, is within a factor of two of expectations for a tokamak of the same size, current, and heating power. Supported by USDOE.

Chapman, B. E.; Almagri, A. F.; Anderson, J. K.; Caspary, K. J.; Clayton, D. J.; den Hartog, D. J.; Ebrahimi, F.; Fiksel, G.; Goetz, J. A.; Kumar, S.; Magee, R. M.; Reusch, J. A.; Sarff, J. S.; Stephens, H. D.; Yang, Y. M.; Bergerson, W. F.; Brower, D. L.; Ding, W. X.; Lin, L.; Combs, S.; Foust, C.

2010-11-01

115

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

NASA Astrophysics Data System (ADS)

First operation of a new generation of MW level, 110 GHz generator 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 mm 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 110 GHz waves into a plasma have been developed at General Atomics 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, Richard L.

1996-12-01

116

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

117

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

118

Rapid Transmutation of High-Level Nuclear Wastes in a Catalyzed Fusion-Driven System  

Microsoft Academic Search

The aim of this study is to investigate the high-level waste (HLW) transmutation potential of fusion-driven transmuter (FDT)\\u000a based on catalyzed DD fusion plasma for various fuel fractions. The Minor actinide (MA) (237Np, 241Am, 243Am and 244Cm) and long-lived fission product (LLFP) (99Tc, 129I and 135Cs) nuclides discharged from high burn-up pressured water reactor-mixed oxide spent fuel are considered as

Nesrin Demir; Gamze Gen; Taner Altunok; Hseyin Yap?c?

2009-01-01

119

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 LiBeF 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

120

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

121

Highly sensitive phage-based biosensor for the detection of beta-galactosidase.  

PubMed

Development of real-time sensor based on the target-specific probe that make possible sensitive, rapid and selective detection and monitoring of the particular antigen molecules could be of substantial importance to the many applications. Because of its high specificity to the target molecules, excellent temperature stability, and easy production, bacterial phage might serve as a powerful biorecognition probe in biosensor applications. Here, we report extremely sensitive and specific label-free direct detection of model antigen, beta-galactosidase (beta-gal), based on surface plasmon resonance (SPR) spectroscopy. The beta-gal specific landscape phage 1G40 has been immobilized on the gold surface of SPR SPREETA sensor chip through physical adsorption [V. Nanduri, A.M. Samoylova, V.Petrenko, V. Vodyanoy and A.L.Simonian, Comparison of optical and acoustic wave phage biosensors, 206th Meeting of The Electrochemical Society, Honolulu, Hawaii, October 3-8, (2004)]. Another non-specific to the beta-gal phage, a wild-type phage F8-5, was used in the reference channel. The concentration-dependent binding of beta-gal in both channels were assessed by monitoring the sensor optical response as a function of time under different experimental conditions, and the concentration of beta-gal was computed in differential mode. Concentrations of beta-gal between 10(-12) M and 10(-7) M could be readily detected, with linear part of calibration curve between 10(-9) M and 10(-6) M. When beta-gal was pre-incubated with different concentrations of free 1G40 phage prior to exposure to the biosensor, concentration-dependent inhibition was observed, indicating on biosensor high specificity toward beta-gal. Apart from a flow through mode used to deliver the samples to the surface for the SPR sensor, batch mode sensing was also employed to study the binding of beta-gal to immobilized phage on the SPR sensor surface. Experiments using a flow through mode provided more consistent results in the full dose range and showed higher sensitivity as opposed to the batch mode studies. The mean K(d) and binding valences for the flow through mode studies was 1.3+/-0.001 nM and 1.5+/-0.03, in comparison to 26+/-0.003 nM and 2.4+/-0.01 for the batch mode studies. The average thickness of phage 1G40 adlayer deposited through flow through and batch mode was 3+/-0.002 and 0.66+/-0.001 nm, respectively. PMID:17418177

Nanduri, Viswaprakash; Balasubramanian, Shankar; Sista, Srinivas; Vodyanoy, Vitaly J; Simonian, Aleksandr L

2007-04-25

122

Super-X divertors and high power density fusion devices  

Microsoft Academic Search

The Super-X Divertor (SXD), a robust axisymmetric redesign of the divertor magnetic geometry that can allow a fivefold increase in the core power density of toroidal fusion devices, is presented. With small changes in poloidal coils and currents for standard divertors, the SXD allows the largest divertor plate radius inside toroidal field coils. This increases the plasma-wetted area by 2-3

P. M. Valanju; M. Kotschenreuther; S. M. Mahajan; John Canik

2009-01-01

123

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

124

The NEXT experiment: A high pressure xenon gas TPC for neutrinoless double beta decay searches  

E-print Network

Neutrinoless double beta decay is a hypothetical, very slow nuclear transition in which two neutrons undergo beta decay simultaneously and without the emission of neutrinos. The importance of this process goes beyond its intrinsic interest: an unambiguous observation would establish a Majorana nature for the neutrino and prove the violation of lepton number. NEXT is a new experiment to search for neutrinoless double beta decay using a radiopure high-pressure xenon gas TPC, filled with 100 kg of Xe enriched in Xe-136. NEXT will be the first large high-pressure gas TPC to use electroluminescence readout with SOFT (Separated, Optimized FuncTions) technology. The design consists in asymmetric TPC, with photomultipliers behind a transparent cathode and position-sensitive light pixels behind the anode. The experiment is approved to start data taking at the Laboratorio Subterr\\'aneo de Canfranc (LSC), Spain, in 2014.

D. Lorca; J. Martn-Albo; F. Monrabal; for the NEXT Collaboration

2012-10-15

125

Multi-Sensor Fusion of Electro-Optic and Infrared Signals for High Resolution Visible Images: Part II  

E-print Network

Multi-Sensor Fusion of Electro-Optic and Infrared Signals for High Resolution Visible Images: Part) fuse original RGB color (EO) images and IR images based on image fusion algorithms; (3) blend the fused. Therein, the image fusion step will be conducted by the quantitative (Yang et al. proposed adaptive multi

126

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

2007-06-01

127

Physics of laser fusion. Volume 3: High-power pulsed lasers  

Microsoft Academic Search

High power pulsed lasers can deliver sufficient energy on inertial confinement fusion (ICF) time scales (0.1 to 10 ns) to heat and compress deuterium tritium fuel to fusion reaction conditions. Several laser systems were examined, including Nd:glass, CO2, KrF, and I2, for their ICF applicability. A great deal of developmental effort has been applied to the Nd:glass laser and the

J. F. Holzrichter; D. Eimerl; E. V. George; J. B. Trenholme; W. W. Simmons; J. T. Hunt

1982-01-01

128

Physics of laser fusion. Volume III. High-power pulsed lasers  

Microsoft Academic Search

High-power pulsed lasers can deliver sufficient energy on inertial-confinement fusion (ICF) time scales (0.1 to 10 ns) to heat and compress deuterium-tritium fuel to fusion-reaction conditions. Several laser systems have been examined, including Nd:glass, CO, KrF, and I, for their ICF applicability. A great deal of developmental effort has been applied to the Nd:glass laser and the CO gas laser

J. F. Holzrichter; D. Eimerl; E. V. George; J. B. Trenholme; W. W. Simmons; J. T. Hunt

1982-01-01

129

The Physics of Advanced High-Gain Targets for Inertial Fusion Energy  

NASA Astrophysics Data System (ADS)

In ca. 2011-2012, the National Ignition Facility is poised to demonstrate fusion ignition and gain in the laboratory for the first time. This key milestone in the development of inertial confinement fusion (ICF) can be expected to engender interest in the development of inertial fusion energy (IFE) and expanded efforts on a number of advanced targets that may achieve high fusion energy gain at lower driver energies. In this tutorial talk, we will discuss the physics underlying ICF ignition and thermonuclear burn, examine the requirements for high gain, and outline candidate R&D programs that will be required to assess the performance of these target concepts under various driver systems including lasers, heavy-ions and pulsed power. Such target concepts include those operating by fast ignition, shock ignition, impact ignition, dual-density, magnetically-insulated, one- and two-sided drive, etc., some of which may have potential to burn advanced, non-DT fusion fuels. We will then delineate the role of such targets in their application to the production of high average fusion power. Here, systems studies of IFE economics suggest that we should strive for target fusion gains of around 100 at drive energies of 1MJ, together with corresponding rep-rates of up to 10Hz and driver electrical efficiencies around 15%. In future years, there may be exciting opportunities to study such ``innovative confinement concepts'' with prospects of fielding them on facilities such as NIF to obtain high fusion energy gains on a single shot basis.

Perkins, L. John

2010-11-01

130

EMD based multi-scale model for high resolution image fusion  

Microsoft Academic Search

High resolution image fusion is a significant focus in the field of image processing. A new image fusion model is presented\\u000a based on the characteristic level of empirical mode decomposition (EMD). The intensity hue saturation (IHS) transform of the\\u000a multi-spectral image first gives the intensity image. Thereafter, the 2D EMD in terms of row-column extension of the 1D EMD\\u000a model

Jian Wang; Jixian Zhang; Zhengjun Liu

2008-01-01

131

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

132

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

133

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

134

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

135

High beta capture and mirror confinement of laser produced plasmas  

Microsoft Academic Search

A dense, mirror confined, target plasma is produced by high power laser irradiation of a solid lithium hydride particle, electrically suspended in a vacuum at the center of an established minimum-B magnetic field. Following expansion in and capture by the magnetic field, this target plasma is irradiated by an energetic neutral hydrogen beam. Charge exchange collisions with energetic beam particles

A. F. Haught; D. H. Polk; W. J. Fader; R. G. Tomlinson; R. A. Jong; W. B. Ard; A. E. Mensing; T. L. Churchill; J. L. Stufflebeam; F. J. Bresnock

1976-01-01

136

Optimal use of beta-blockers in high-risk hypertension: a guide to dosing equivalence.  

PubMed

Hypertension is the number one diagnosis made by primary care physicians, placing them in a unique position to prescribe the antihypertensive agent best suited to the individual patient. In individuals with diabetes mellitus, blood pressure (BP) levels>130/80 mmHg confer an even higher risk for cardiovascular and renal disease, and these patients will benefit from aggressive antihypertensive treatment using a combination of agents. beta-blockers are playing an increasingly important role in the management of hypertension in high-risk patients. beta-blockers are a heterogeneous class of agents, and this review presents the differences between beta-blockers and provides evidence-based protocols to assist in understanding dose equivalence in the selection of an optimal regimen in patients with complex needs. The clinical benefits provided by beta-blockers are only effective if patients adhere to medication treatment long term. beta-blockers with proven efficacy, once-daily dosing, and lower side effect profiles may become instrumental in the treatment of hypertensive diabetic and nondiabetic patients. PMID:20539838

McGill, Janet B

2010-01-01

137

Free Boundary, High Beta Equilibrium in a Large Aspect Ratio Tokamak with Nearly  

E-print Network

Free Boundary, High Beta Equilibrium in a Large Aspect Ratio Tokamak with Nearly Circular Plasma Boundary H. Qin A. Reiman September 25, 1996 Abstract An analytic solution is obtained for free. In the absence of surface currents at the plasma­vacuum in­ terface, the free­boundary equilibrium solution

138

Free Boundary, High Beta Equilibrium in a Large Aspect Ratio Tokamak with Nearly  

E-print Network

Free Boundary, High Beta Equilibrium in a Large Aspect Ratio Tokamak with Nearly Circular Plasma Boundary H. Qin A. Reiman September 25, 1996 Abstract An analytic solution is obtained for free. In the absence of surface currents at the plasma-vacuum in- terface, the free-boundary equilibrium solution

139

MHD instabilities and their control in high-beta plasmas in KSTAR  

SciTech Connect

We established 3 specific tasks as follows: Task 1 - Investigate the MHD activity during the current ramp-up phase with shaped plasmas; Task 2 - Develop a theoretical model that may show the hollowness dependent instability; Task 3 - Explore the beta-limiting instabilities. To address each task, FAR-TECH actively participated in the 2012 KSTAR run-campaign, which helped us make productive progress. Specifically, the shaping dependence of MHD activity during current ramp-up phase was investigated using dedicated run-time in KSTAR (October 4 and 9, 2012), which was also attempted to address the hollowness of temperature (or pressure) profiles. Also, a performance-limiting disruption, which occurred in a relatively high intermediate beta plasma (shot 7110) in KSTAR ({beta}{sub N} ~ 1.7), was studied, and the preliminary analysis shows that the disruption might not be stability-limited but likely density-limited.

In, Yongkyoon

2013-02-06

140

Cysteines flanking the internal fusion peptide are required for the avian sarcoma/leukosis virus glycoprotein to mediate the lipid mixing stage of fusion with high efficiency.  

PubMed

We previously showed that the cysteines flanking the internal fusion peptide of the avian sarcoma/leukosis virus subtype A (ASLV-A) Env (EnvA) are important for infectivity and cell-cell fusion. Here we define the stage of fusion at which the cysteines are required. The flanking cysteines are dispensable for receptor-triggered membrane association but are required for the lipid mixing step of fusion, which, interestingly, displays a high pH onset and a biphasic profile. Second-site mutations that partially restore infection partially restore lipid mixing. These findings indicate that the cysteines flanking the internal fusion peptide of EnvA (and perhaps by analogy Ebola virus glycoprotein) are important for the foldback stage of the conformational changes that lead to membrane merger. PMID:18184714

Delos, Sue E; Brecher, Matthew B; Chen, Zaoying; Melder, Deborah C; Federspiel, Mark J; White, Judith M

2008-03-01

141

High-beta Injection into a Magnetic Mirror Field  

Microsoft Academic Search

Axial lnjection of a high-density helium plasma into a magnetic mirror ; is experimentally studied. Observations of the plasma-field interaction are made ; with magnetic probes, electrostatic probes, piezoelectric probes, and an optical ; monochromator that analyzes emission-line profiles. In the central plane of the ; mirror a density of (2 plus or minus 1) x 10¹⁵ ions\\/cm³ and a

F. R. Scott; O. C. Eldridge Jr.

1961-01-01

142

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

143

Proteasome dysfunction mediates high glucose-induced apoptosis in rodent beta cells and human islets.  

PubMed

The ubiquitin/proteasome system (UPS), a major cellular protein degradation machinery, plays key roles in the regulation of many cell functions. Glucotoxicity mediated by chronic hyperglycaemia is detrimental to the function and survival of pancreatic beta cells. The aim of our study was to determine whether proteasome dysfunction could be involved in beta cell apoptosis in glucotoxic conditions, and to evaluate whether such a dysfunction might be pharmacologically corrected. Therefore, UPS activity was measured in GK rats islets, INS-1E beta cells or human islets after high glucose and/or UPS inhibitor exposure. Immunoblotting was used to quantify polyubiquitinated proteins, endoplasmic reticulum (ER) stress through CHOP expression, and apoptosis through the cleavage of PARP and caspase-3, whereas total cell death was detected through histone-associated DNA fragments measurement. In vitro, we found that chronic exposure of INS-1E cells to high glucose concentrations significantly decreases the three proteasome activities by 20% and leads to caspase-3-dependent apoptosis. We showed that pharmacological blockade of UPS activity by 20% leads to apoptosis in a same way. Indeed, ER stress was involved in both conditions. These results were confirmed in human islets, and proteasome activities were also decreased in hyperglycemic GK rats islets. Moreover, we observed that a high glucose treatment hypersensitized beta cells to the apoptotic effect of proteasome inhibitors. Noteworthily, the decreased proteasome activity can be corrected with Exendin-4, which also protected against glucotoxicity-induced apoptosis. Taken together, our findings reveal an important role of proteasome activity in high glucose-induced beta cell apoptosis, potentially linking ER stress and glucotoxicity. These proteasome dysfunctions can be reversed by a GLP-1 analog. Thus, UPS may be a potent target to treat deleterious metabolic conditions leading to type 2 diabetes. PMID:24642635

Broca, Christophe; Varin, Elodie; Armanet, Mathieu; Tourrel-Cuzin, Ccile; Bosco, Domenico; Dalle, Stphane; Wojtusciszyn, Anne

2014-01-01

144

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

145

High quality actively cooled plasma facing components for fusion  

SciTech Connect

This paper interweaves some suggestions for developing actively-cooled PFCs (plasma facing components) for future fusion devices with supporting examples taken from the design, fabrication and operation of Tore Supra`s Phase III Outboard Pump Limiter (OPL). This actively-cooled midplane limiter, designed for heat and particle removal during long pulse operation, has been operated in essentially thermally steady state conditions. From experience with testing to identify braze flaws in the OPL, recommendations are made to analyze the impact of joining flaws on thermal-hydraulic performance of PFCs and to validate a method of inspection for such flaws early in the design development. Capability for extensive in-service monitoring of future PFCs is also recommended and the extensive calorimetry and IR thermography used to confirm and update safe operating limits for power handling of the OPL are reviewed.

Nygren, R.

1993-12-31

146

Possible Origin of Improved High Temperature Performance of Hydrothermally Aged Cu/Beta Zeolite Catalysts  

SciTech Connect

The hydrothermal stability of Cu/beta NH3 SCR catalysts are explored here. In particular, this paper focuses on the interesting ability of this catalyst to maintain and even enhance high-temperature performance for the "standard" SCR reaction after modest (900 C, 2 hours) hydrothermal aging. Characterization of the fresh and aged catalysts was performed with an aim to identify possible catalytic phases responsible for the enhanced high temperature performance. XRD, TEM and 27Al NMR all showed that the hydrothermally aging conditions used here resulted in almost complete loss of the beta zeolite structure between 1 and 2 hours aging. While the 27Al NMR spectra of 2 and 10 hour hydrothermally-aged catalysts showed significant loss of a peak associated with tetrahedrally-coordinated Al species, no new spectral features were evident. Two model catalysts, suggested by these characterization data as possible mimics of the catalytic phase formed during hydrothermal aging of Cu/beta, were prepared and tested for their performance in the "standard" SCR and NH3 oxidation reactions. The similarity in their reactivity compared to the 2 hour hydrothermally-aged Cu/beta catalyst suggests possible routes for preparing multi-component catalysts that may have wider temperature windows for optimum performance than those provided by current Cu/zeolite catalysts.

Peden, Charles HF; Kwak, Ja Hun; Burton, Sarah D.; Tonkyn, Russell G.; Kim, Do Heui; Lee, Jong H.; Jen, H. W.; Cavattaio, Giovanni; Cheng, Yisun; Lambert, Christine

2012-04-30

147

A Multi-beamlet High Current Injector for Heavy Ion Fusion  

Microsoft Academic Search

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,

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

2004-01-01

148

High heat flux experiments of plasma facing components for next fusion devices  

Microsoft Academic Search

To develop plasma facing components (PFC) for the next fusion devices, JAERI has been carrying out high heat flux and high particle flux experiments on the divertor modules and candidate materials in JAERI Electron Beam Irradiation System (JEBIS). (1) To investigate the feasibility and the advantage of a saddle type divertor modules, which has unidirectional (1-D) carbon fiber reinforced carbon

K. Nakamura; M. Akiba; S. Suzuki; K. Satoh; K. Yokoyama; M. Dairaku; M. Araki; Y. Ohara; T. Inoue; Y. Okumura; I. Smid

1993-01-01

149

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

150

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. PMID:24151535

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

151

High-Adiabat High-Foot Inertial Confinement Fusion Implosion Experiments on the National Ignition Facility  

NASA Astrophysics Data System (ADS)

This Letter reports on a series of high-adiabat implosions of cryogenic layered deuterium-tritium (DT) capsules indirectly driven by a "high-foot" laser drive pulse at the National Ignition Facility. High-foot implosions have high ablation velocities and large density gradient scale lengths and are more resistant to ablation-front Rayleigh-Taylor instability induced mixing of ablator material into the DT hot spot. Indeed, the observed hot spot mix in these implosions was low and the measured neutron yields were typically 50% (or higher) of the yields predicted by simulation. On one high performing shot (N130812), 1.7 MJ of laser energy at a peak power of 350 TW was used to obtain a peak hohlraum radiation temperature of 300 eV. The resulting experimental neutron yield was (2.40.05)1015 DT, the fuel ?R was (0.860.063) g/cm2, and the measured Tion was (4.20.16) keV, corresponding to 8 kJ of fusion yield, with 1/3 of the yield caused by self-heating of the fuel by ? particles emitted in the initial reactions. The generalized Lawson criteria, an ignition metric, was 0.43 and the neutron yield was 70% of the value predicted by simulations that include ?-particle self-heating.

Park, H.-S.; Hurricane, O. A.; Callahan, D. A.; Casey, D. T.; Dewald, E. L.; Dittrich, T. R.; Dppner, T.; Hinkel, D. E.; Berzak Hopkins, L. F.; Le Pape, S.; Ma, T.; Patel, P. K.; Remington, B. A.; Robey, H. F.; Salmonson, J. D.; Kline, J. L.

2014-02-01

152

Application of Magnetized Target Fusion to High-Energy Space Propulsion  

NASA Technical Reports Server (NTRS)

Most fusion propulsion concepts that have been investigated in the past employ some form of inertial or magnetic confinement. Although the prospective performance of these concepts is excellent, the fusion processes on which these concepts are based still require considerable development before they can be seriously considered for actual applications. Furthermore, these processes are encumbered by the need for sophisticated plasma and power handling systems that are generally quite inefficient and have historically resulted in large, massive spacecraft designs. Here we present a comparatively new approach, Magnetized Target Fusion (MTF), which offers a nearer-term avenue for realizing the tremendous performance benefits of fusion propulsion'. The key advantage of MTF is its less demanding requirements for driver energy and power processing. Additional features include: 1) very low system masses and volumes, 2) high gain and relatively low waste heat, 3) substantial utilization of energy from product neutrons, 4) efficient, low peak-power drivers based on existing pulsed power technology, and 5) very high Isp, specific power and thrust. MTF overcomes many of the problems associated with traditional fusion techniques, thus making it particularly attractive for space applications. Isp greater than 50,000 seconds and specific powers greater than 50 kilowatts/kilogram appear feasible using relatively near-term pulse power and plasma gun technology.

Thio, Y. C. F.; Schmidt, G. R.; Kirkpatrick, R. C.; Rodgers, Stephen L. (Technical Monitor)

2001-01-01

153

Beta Beams  

NASA Astrophysics Data System (ADS)

The ultimate goal of neutrino oscillation physics is the search for leptonic CP violation, which will require neutrino beams that are much more intense and pure than those used in present experiments. Beta beams are an attractive innovative possibility in this direction. Neutrinos are generated by the beta decays of radioactive nuclei and are accelerated at very high energies. The resulting neutrino beam consists of only one easily predictable flavor of neutrinos (ve or [Formula: see text]). A realistic beta beam design, which has already been demonstrated by the Eurisol Design Study, is based on CERN's PS and SPS accelerators. The beta beam concept has also been extended in several other directions, including high energy, high Q, electron capture, and low energy. Both the accelerator complex and the physics potential of a neutrino experiment are reviewed here. We emphasize the beta beam design based on the CERN PS and SPS, but we also discuss other possibilities.

Lindroos, Mats; Mezzetto, Mauro

2010-11-01

154

Highly sensitive and selective spectrofluorimetric determination of tolnaftate through the formation of ternary inclusion complex of beta-naphthol/beta-cyclodextrin/anionic surfactant system.  

PubMed

An indirect spectrofluorimetric method with high sensitivity and selectivity was developed for the determination of antifungal drug: tolnaftate (TNF), depending on the supramolecular multi-recognition interaction among the anionic surfactant sodium laurylsulfate (SLS), beta-cyclodextrin (beta-CD) and beta-naphthol (ROH). The mechanism of the inclusion was studied and discussed by means of fluorescence spectrum, infra-red spectrograms and (1)HNMR spectroscopy. Results showed that the naphthalene ring of ROH and the hydrophobic hydrocarbon chain of SLS were included into the beta-CD's cavity to form a ROH:SLS:beta-CD ternary inclusion complex with stoichiometry of 1:1:1 at room temperature, which provided effective protection for the excited state of ROH. At lambda(ex)/lambda(em)=273/360 nm, the fluorescence intensity was linear over a tolnaftate concentration range of 2.46 x 10(-9) to 2.10 x 10(-6)mol L(-1). The detection limit and relative standard deviation was 7.50 x 10(-10)mol L(-1) and 1.4%, respectively. The interference of 31 foreign substances was slight. The proposed method had been successfully applied to the determination of tolnaftate in artificial mixed samples with almost quantitative recovery. PMID:18970541

Tang, Bo; Wang, Xu; Wang, Guangli; Yu, Chengguang; Chen, Zhenzhen

2006-03-15

155

Cold fusion, Alchemist's dream  

SciTech Connect

In this report the following topics relating to cold fusion are discussed: muon catalysed cold fusion; piezonuclear fusion; sundry explanations pertaining to cold fusion; cosmic ray muon catalysed cold fusion; vibrational mechanisms in excited states of D{sub 2} molecules; barrier penetration probabilities within the hydrogenated metal lattice/piezonuclear fusion; branching ratios of D{sub 2} fusion at low energies; fusion of deuterons into {sup 4}He; secondary D+T fusion within the hydrogenated metal lattice; {sup 3}He to {sup 4}He ratio within the metal lattice; shock induced fusion; and anomalously high isotopic ratios of {sup 3}He/{sup 4}He.

Clayton, E.D.

1989-09-01

156

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

157

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

158

In-situ observation of the alpha/beta cristobalite transition using high voltage electron microscopy  

SciTech Connect

A high temperature water vapor phase is expected to persist in the vicinity of high level radioactive waste packages for several hundreds of years. The authors have begun an investigation of the structural and chemical effects of water on cristobalite because of its abundance in the near field environment. A high voltage transmission electron microscope (HVEM) investigation of bulk synthesized {alpha}-cristobalite to be used in single phase dissolution and precipitation kinetics experiments revealed the presence {beta}-cristobalite, quartz and amorphous silica, in addition to {alpha}-cristobalite. Consequently, this apparent metastable persistence of {beta}-cristobalite and amorphous silica during the synthesis of {alpha}-cristobalite was investigated using a heating stage and an environmental cell installed in the HVEM that allowed the introduction of either dry CO{sub 2} or a CO{sub 2} + H{sub 2}O vapor. Preliminary electron diffraction evidence suggests that the presence of water vapor affected the {alpha}-{beta} transition temperature. Water vapor may also be responsible for the development of an amorphous silica phase at the transition that may persist over an interval of several tens of degrees. The amorphous phase was not documented during the dry heating experiments. 20 refs., 7 figs., 5 tabs.

Meike, A. [Lawrence Berkeley Lab., CA (USA); Glassley, W. [Lawrence Livermore National Lab., CA (USA)

1989-10-01

159

High Fusion Rates with Circular Plate Fixation for Four-corner Arthrodesis of the Wrist  

Microsoft Academic Search

Background Scaphoid excision and four-corner fusion is commonly performed to reconstruct advanced scapholunate collapse and scaphoid\\u000a nonunion with collapse. Metallic plates were introduced for achieving fixation of the four carpal bones. Although the developer\\u000a reported high rates of fusion, several other early reports of circular plate fixation suggest higher complication rates and\\u000a inferior outcomes compared with traditional fixation techniques.\\u000a \\u000a \\u000a \\u000a Questions\\/Purposes

Ben Bedford; S. Steven Yang

2010-01-01

160

INFORM Lab: a testbed for high-level information fusion and resource management  

Microsoft Academic Search

DRDC Valcartier and MDA have created an advanced simulation testbed for the purpose of evaluating the effectiveness of Network Enabled Operations in a Coastal Wide Area Surveillance situation, with algorithms provided by several universities. This INFORM Lab testbed allows experimenting with high-level distributed information fusion, dynamic resource management and configuration management, given multiple constraints on the resources and their communications

Pierre Valin; Adel Guitouni; Eloi Boss; Hans Wehn; Jens Happe

2011-01-01

161

Progress in laboratory high gain ICF (Inertial Confinement Fusion): Prospects for the future  

Microsoft Academic Search

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

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

1988-01-01

162

High total dose irradiation experiments on fiber optic components for fusion reactor environments  

Microsoft Academic Search

Optical fiber technology is seriously considered for communication and monitoring applications during the operation and maintenance of future thermonuclear fusion reactors. Their environment is characterized, in particular, by possibly high gamma dose-rates and total doses up to 100 MGy. The feasibility of applying photonic technique in such intense radiation fields therefore needs to be assessed. Whereas many reports deal with

Francis Berghmans; Marco Van Uffelen; Antoine Nowodzinski; Benoit Brichard; Frans Vos; Philippe Jucker; Marc C. Decreton

1999-01-01

163

Experimental investigation of opacity models for stellar interior, inertial fusion, and high energy density plasmasa...  

E-print Network

Experimental investigation of opacity models for stellar interior, inertial fusion, and high energy; accepted 15 December 2008; published online 23 March 2009 Theoretical opacities are required, and Z pinches depends on the opacities of mid-atomic-number elements over a wide range of temperatures

164

Isolation of a highly specific ligand for the alpha 5 beta 1 integrin from a phage display library  

PubMed Central

Our previous studies showed that the alpha 5 beta 1 integrin selects cysteine pair-containing RGD peptides from a phage display library based on a random hexapeptide. We have therefore searched for more selective peptides for this integrin using a larger phage display library, where heptapeptides are flanked by cysteine residues, thus making the inserts potentially cyclic. Most of the phage sequences that bound to alpha 5 beta 1 (69 of 125) contained the RGD motif. Some of the heptapeptides contained an NGR motif. As the NGR sequence occurs in the cell-binding region of the fibronectin molecule, this sequence could contribute to the specific recognition of fibronectin by alpha 5 beta 1. Selection for high affinity peptides for alpha 5 beta 1 surprisingly yielded a sequence RRETAWA that does not bear obvious resemblance to known integrin ligand sequences. The synthetic cyclic peptide GACRRETAWACGA (*CRRETAWAC*) was a potent inhibitor of alpha 5 beta 1-mediated cell attachment to fibronectin. This peptide is nearly specific for the alpha 5 beta 1 integrin, because much higher concentrations were needed to inhibit the alpha v beta 1 integrin, and there was no effect on alpha v beta 3- and alpha v beta 5-mediated cell attachment to vitronectin. The peptide also did not bind to the alpha IIb beta 3 integrin. *CRRETAWAC* appears to interact with the same or an overlapping binding site in alpha 5 beta 1 as RGD, because cell attachment to *CRRETAWAC* coated on plastic was divalent cation dependent and could be blocked by an RGD-containing peptide. These results reveal a novel binding specificity in the alpha 5 beta 1 integrin. PMID:7507494

1994-01-01

165

Atlantoaxial transarticular screw fixation and posterior fusion using ultra-high-molecular-weight polyethylene cable.  

PubMed

This article attempts to evaluate the effectiveness of the ultra-high-molecular-weight polyethylene (UHMW-PE) cable system in atlantoaxial transarticular screw fixation and posterior fusion through the clinical results of 10 postoperative patients with atlantoaxial subluxation secondary to rheumatoid arthritis. Among them, one patient with only one screw placed owing to an anomalous vertebral artery had the correction loss of the 3-mm atlas-dens interval after surgery. Another patient had a second operation to remove the screw and cable after 2 years 11 months because a unilateral transarticular screw had come to protrude through the lateral mass of the atlas ventrally. All patients had achieved C1-C2 osseous fusion without any complications associated with this cable system. The UHMW-PE cable is a very useful material as sublaminar wiring in atlantoaxial transarticular screw fixation and posterior fusion. PMID:16189448

Yonezawa, Ikuho; Arai, Yasuhisa; Tsuji, Takaaki; Takahashi, Masaki; Kurosawa, Hisashi

2005-10-01

166

High-beta steady-state research with integrated modeling in the JT-60 Upgrade  

SciTech Connect

Improvement of high-beta performance and its long sustainment was obtained with ferritic steel tiles in the JT-60 Upgrade (JT-60U) [T. Fujita et al., Phys. Plasmas 50, 104 (2005)], which were installed inside the vacuum vessel to reduce fast ion loss by decreasing the toroidal field ripple. When a separation between the plasma surface and the wall was small, high-beta plasmas reached the ideal wall stability limit, i.e., the ideal magnetohydrodynamics stability limit with the wall stabilization. A small rotation velocity of 0.3% of the Alfven velocity was found to be effective for suppressing the resistive wall mode. Sustainment of the high normalized beta value of {beta}{sub N}=2.3 has been extended to 28.6 s ({approx}15 times the current diffusion time) by improvement of the confinement and increase in the net heating power. Based on the research in JT-60U experiments and first-principle simulations, integrated models of core, edge-pedestal, and scrape-off-layer (SOL) divertors were developed, and they clarified complex features of reactor-relevant plasmas. The integrated core plasma model indicated that the small amount of electron cyclotron (EC) current density of about half the bootstrap current density could effectively stabilize the neoclassical tearing mode by the localized EC current accurately aligned to the magnetic island center. The integrated edge-pedestal model clarified that the collisionality dependence of energy loss due to the edge-localized mode was caused by the change in the width of the unstable mode and the SOL transport. The integrated SOL-divertor model clarified the effect of the exhaust slot on the pumping efficiency and the cause of enhanced radiation near the X-point multifaceted asymmetric radiation from edge. Success in these consistent analyses using the integrated code indicates that it is an effective means to investigate complex plasmas and to control the integrated performance.

Ozeki, T. [Fusion Research and Development Directorate, Japan Atomic Energy Agency, Naka, Ibaraki 311-0193 (Japan)

2007-05-15

167

Ra: A high efficiency, D-/sup 3/He, tandem mirror fusion reactor: Appendix C  

SciTech Connect

The Ra tandem mirror fusion reactor concept features inherent safety, high net plant efficiency, low cost of electricity, low radioactive waste generation, low activation, highly efficient direct conversion, thin radiation shields, and axisymmetric magnets. The safety and environmental features are achieved through the use of D/He-3 fuel, while the high efficiency derives from a new operating mode. ICRF stabilization allows an axisymmetric magnet set. 11 refs., 5 figs., 3 tabs.

Santarius, J.F.; Attaya, H.; Corradini, M.L.; El-Guebaly, L.A.; Emmert, G.A.; Kulcinski, G.L.; Larsen, E.M.; Maynard, C.W.; Musicki, Z.; Sawan, M.E.

1987-01-01

168

Protective effect of berberine on beta cells in streptozotocin- and high-carbohydrate/high-fat diet-induced diabetic rats.  

PubMed

Oxidative stress in diabetes coexists with a reduction in the antioxidant status, which can further increase the deleterious effects of free radicals. Berberine is one of the main alkaloids of Rhizoma coptidis which has been used to treat diabetes for more than 1400 years in China. The present study was designed to evaluate the protective effects of berberine against beta cell damage and antioxidant of pancreas in diabetic rats. Diabetic rats with hyperlipidemia were induced by intraperitoneally injection 35 mg/kg streptozotocin and a high-carbohydrate/high-fat diet. Rats were divided into 7 groups at the end of week 16: untreated control, untreated diabetic, 75, 150, 300 mg/kg berberine-treated diabetic, 100 mg/kg fenofibrate-treated, and 4 mg/kg rosiglitazone-treated. After 16 weeks treatment, serum insulin level, insulin expression in pancreas, and malonaldehyde content, superoxide dismutase activity in pancreatic homogenate were assayed. Pancreas was examined by hematoxylin/eosin staining and transmission electron microscope. Pancreas to body weight ratio, insulin level, insulin sensitivity index, malonaldehyde content and superoxide dismutase activity were altered in diabetic rats, and were near control levels treated with 150, 300 mg/kg berberine. Mitochondrial vacuolization and swelling, dilatation of the endoplasmic reticulum were observed in beta cells of diabetic rats. The pancreatic islet area atrophied and secretory granules of beta cells decreased in diabetic rats. Slight pathological changes existed in beta cells of 150, 300 mg/kg berberine-treated diabetic pancreas. These findings suggest that berberine has protective effect for diabetes through increasing insulin expression, beta cell regeneration, antioxidant enzyme activity and decreasing lipid peroxidation. PMID:19374872

Zhou, Jiyin; Zhou, Shiwen; Tang, Jianlin; Zhang, Kebin; Guang, Lixia; Huang, Yongping; Xu, Ying; Ying, Yi; Zhang, Le; Li, Dandan

2009-03-15

169

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

170

Papaya glutamine cyclase, a plant enzyme highly resistant to proteolysis, adopts an all-beta conformation.  

PubMed

Glutamine cyclases catalyse the conversion of L-glutaminyl-peptides into 5-oxoprolyl-peptides with the concomitant liberation of ammonia. We report here biophysical characterisation of the glutamine cyclase present in the laticiferous cells of the plant Carica papaya. After purification to near homogeneity, this enzyme was subjected to limited proteolysis and found to exhibit a high resistance to degradation and nicking. The structural reasons for this property were examined using circular dichroism and infrared spectroscopies. By combining the analyses of the infrared and CD spectra of papaya glutamine cyclase, its susceptibility to proteolysis, and its hydrogen-deuterium exchange characteristics, we conclude that this protein contains extensive beta-sheet structure and is likely to have only short immobile loops connecting its beta-strands. PMID:9851712

Oberg, K A; Ruysschaert, J M; Azarkan, M; Smolders, N; Zerhouni, S; Wintjens, R; Amrani, A; Looze, Y

1998-11-15

171

Electromagnetic stabilization of tokamak microturbulence in a high-$\\beta$ regime  

E-print Network

The impact of electromagnetic stabilization and flow shear stabilization on ITG turbulence is investigated. Analysis of a low-$\\beta$ JET L-mode discharge illustrates the relation between ITG stabilization, and proximity to the electromagnetic instability threshold. This threshold is reduced by suprathermal pressure gradients, highlighting the effectiveness of fast ions in ITG stabilization. Extensive linear and nonlinear gyrokinetic simulations are then carried out for the high-$\\beta$ JET hybrid discharge 75225, at two separate locations at inner and outer radii. It is found that at the inner radius, nonlinear electromagnetic stabilization is dominant, and is critical for achieving simulated heat fluxes in agreement with the experiment. The enhancement of this effect by suprathermal pressure also remains significant. It is also found that flow shear stabilization is not effective at the inner radii. However, at outer radii the situation is reversed. Electromagnetic stabilization is negligible while the flow...

Citrin, J; Goerler, T; Jenko, F; Mantica, P; Told, D; Bourdelle, C; Hatch, D R; Hogeweij, G M D; Johnson, T; Pueschel, M J; Schneider, M

2014-01-01

172

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

173

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

174

High Density Plasma Beam Target Fusion: An Alternative form of Inertial Confinement to Ignition  

NASA Astrophysics Data System (ADS)

A scaling law has been demonstrated for a plasma gun in a 30 m diameter space chamber. Using a specific combination of delay time between the gas valve opening and operation of a capacitor bank switch, and the capacitor bank's voltage, the deflagration gun (Ref. 1) is capable of producing high kinetic energy and at a high density beam. Using a convergent gun barrel it is possible to compress beam density by a factor of 100. A 10^17/c.c.beam was obtained. If the kinetic energy is at 280 Kev (fusion threshold) Neutron flux up to 5 x 10^19 could be produced in a 1 micro-second period. This represents 500 MJ of energy yield. If the classical fusion energy data were in error by a factor of 100 that still would yield 5 MJ of fusion energy. Results obtained from experiments in the 30 m diameter space chamber have demonstrated such a capability using a 120 KV capacitor bank with 200 KJ of stored energy (Ref. 1). A very small scale experiment has demonstrated a yield of 10^15 neutrons using less than 10 kJ of capacitor energy.References:1. Cheng, D.Y. 1970 Plasma Deflagration and the Properties of a Coaxial Plasma Deflagration Gun. Nuclear Fusion, 10, pp. 305- 317

Cheng, Dah Yu

2005-10-01

175

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

176

Options for the use of high temperature superconductor in tokamak fusion reactor designs  

Microsoft Academic Search

The use of high temperature superconductors (HTS) in long term tokamak fusion reactors is analyzed in this paper. The well-documented physical properties of high temperature superconductors are used in the evaluation. Short-sample wires and tapes of Bi2Sr2CanCun+1Oy materials, with n=1, 2 (referred to as BSCCO), and YBCO (YBa2CuO7?x) tapes approach their single-crystal performance limits. They provide a useful reference frame

L. Bromberg; M. Tekula; L. A El-Guebaly; R Miller

2001-01-01

177

TGF-beta(1) and Smad4 overexpression induce a less invasive phenotype in highly invasive spindle carcinoma cells.  

PubMed

We have examined the effect of transforming growth factor beta(1) (TGF-beta(1)) and overexpression of the Smad4 gene on the phenotype of Car C, a ras mutated highly malignant spindle carcinoma cell line. TGF-beta(1)-treated Car C cells overexpressing Smad4 spread with a flattened morphology with membrane ruffles abundant in vinculin and show a reduction in their invasive abilities. TGF-beta(1) treatment and overexpression of Smad4 also enhanced the production of PAI-1 measured by the activation of the p3TP-lux reporter gene containing a PAI-1-related promoter. This activation was abolished with a dominant-negative Smad4 construct. These results lead us to conclude that both TGF-beta(1) and Smad4 overexpression reduce the invasive potential of Car C cells, probably via the Smad pathway. PMID:12044892

Santibez, Juan Francisco; Quintanilla, Miguel; Martnez, Jorge

2002-06-01

178

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

179

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

180

Dust in fusion devices---a multi-faceted problem connecting high- and low-temperature plasma physics  

Microsoft Academic Search

Small particles with sizes between a few nanometers and a few 10 m (dust) are formed in fusion devices by plasma surface interaction processes. Though it is not a major problem today, dust is considered a problem that could arise in future long pulse fusion devices. This is primarily due to its radioactivity and due to its very high chemical

J. Winter

2004-01-01

181

Fusion neutron test facility requirements for interactive effects in structural and high-heat-flux components  

NASA Astrophysics Data System (ADS)

A relevant design data base is needed for structural components in near-term and commercial fusion devices. A high-flux, high-fluence fusion neutron test facility is required for testing the failure mechanisms and lifetime-limiting features for first wall, blanket, and high-heat-flux components. We describe here the key aspects of the fusion environment which influence the response of structural and high-heat-flux components. In addition to test capabilities for fundamental radiation-effects phenomena, e.g., swelling, creep, embrittlement, and hardening, it is shown that the facility must provide an adequate range of conditions for accelerated tests to study the limitations on component lifetime due to the interaction between such fundamental phenomena. In high-heat-flux components, testing of the failure mechanisms of duplex structures is shown to require maintenance of an appropriate temperature gradient in the 14-MeV neutron field. Thermal stresses are shown to result in component failure, particularly when the degradation in the thermal conductivity and mechanical properties by irradiation are considered. Several factors are discussed for assessment of the failure modes of the first wall and blanket structures. These are displacement-damage dose and dose rate, the amount of helium gas generated, the magnitude of irradiation and thermal creep, prototypical temperature and temperature-gradient distributions, module geometry, and external mechanical constraints.

Ghoniem, N. M.; Whitley, J. B.

1989-12-01

182

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

183

INFORM Lab: a testbed for high-level information fusion and resource management  

NASA Astrophysics Data System (ADS)

DRDC Valcartier and MDA have created an advanced simulation testbed for the purpose of evaluating the effectiveness of Network Enabled Operations in a Coastal Wide Area Surveillance situation, with algorithms provided by several universities. This INFORM Lab testbed allows experimenting with high-level distributed information fusion, dynamic resource management and configuration management, given multiple constraints on the resources and their communications networks. This paper describes the architecture of INFORM Lab, the essential concepts of goals and situation evidence, a selected set of algorithms for distributed information fusion and dynamic resource management, as well as auto-configurable information fusion architectures. The testbed provides general services which include a multilayer plug-and-play architecture, and a general multi-agent framework based on John Boyd's OODA loop. The testbed's performance is demonstrated on 2 types of scenarios/vignettes for 1) cooperative search-and-rescue efforts, and 2) a noncooperative smuggling scenario involving many target ships and various methods of deceit. For each mission, an appropriate subset of Canadian airborne and naval platforms are dispatched to collect situation evidence, which is fused, and then used to modify the platform trajectories for the most efficient collection of further situation evidence. These platforms are fusion nodes which obey a Command and Control node hierarchy.

Valin, Pierre; Guitouni, Adel; Boss, Eloi; Wehn, Hans; Happe, Jens

2011-05-01

184

Influence of transmutation and high neutron exposure on materials used in fission-fusion correlation experiments  

SciTech Connect

This paper explores the response of three different materials to high fluence irradiation as observed in recent fusion-related experiments. While helium at fusion-relevant levels influences the details of the microstructure of Fe--Cr--Ni alloys somewhat, the resultant changes in swelling and tensile behavior are relatively small. Under conditions where substantially greater-than-fusion levels of helium are generated, however, an extensive refinement of microstructure can occur, leading to depression of swelling at lower temperatures and increased strengthening at all temperatures studied. The behavior of these alloys is dominated by their tendency to converge to saturation microstructures which encourage swelling. Irradiations of nickel are dominated by its tendency to develop a different type of saturation microstructure that discourages further void growth. Swelling approaches saturation levels that are remarkably insensitive to starting microstructure and irradiation temperature. The rate of approach to saturation is very sensitive to variables such as helium, impurities, dislocation density and displacement rate, however. Copper exhibits a rather divergent response depending on the property measured. Transmutation of copper to nickel and zinc plays a large role in determining electrical conductivity but almost no role in void swelling. Each of these three materials offers different challenges in the interpretation of fission-fusion correlation experiments.

Garner, F.A.

1990-07-01

185

Identification and confirmation of molecular markers and orange flesh color associated with major QTL for high beta-carotene content in muskmelon  

E-print Network

-carotene content, flesh color, and flesh color intensity. Bulk segregent analysis was used with RAPD markers to identify molecular markers associated with high beta-carotene content. Flesh color and flesh color intensity both had significant relationships with beta...

Napier, Alexandra Bamberger

2009-05-15

186

Drift wave instabilities in a high beta multispecies plasma. [in Jupiter and Saturn atmosphere  

NASA Technical Reports Server (NTRS)

The dispersion relation for drift-Alfven waves in two-component (cold and hot), high beta inhomogeneous multispecies plasma containing protons, oxygen, and sulfur ions is solved numerically. The magnetic field is assumed to have a gradient in simple slab geometry configuration. The plasma ion composition consists of H, O, S, SO2, and Na ions. The effect of heavy ions and multiple charge states on the growth rates has been numerically estimated for assumed ion compositions. The numerical calculations of growth rates also have been performed by using ion composition and plasma parameters based on Voyager spacecraft in the magnetospheres of Jupiter and Saturn.

Patel, V. L.; Ng, P. H.; Ludlow, G. R.

1984-01-01

187

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

188

"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.

189

The NIF: An international high energy density science and inertial fusion user facility  

NASA Astrophysics Data System (ADS)

The National Ignition Facility (NIF), a 1.8-MJ/500-TW Nd:Glass laser facility designed to study inertial confinement fusion (ICF) and high-energy-density science (HEDS), is operational at Lawrence Livermore National Laboratory (LLNL). A primary goal of NIF is to create the conditions necessary to demonstrate laboratory-scale thermonuclear ignition and burn. NIF experiments in support of indirect-drive ignition began late in FY2009 as part of the National Ignition Campaign (NIC), an international effort to achieve fusion ignition in the laboratory. To date, all of the capabilities to conduct implosion experiments are in place with the goal of demonstrating ignition and developing a predictable fusion experimental platform in 2012. The results from experiments completed are encouraging for the near-term achievement of ignition. Capsule implosion experiments at energies up to 1.6 MJ have demonstrated laser energetics, radiation temperatures, and symmetry control that scale to ignition conditions. Of particular importance is the demonstration of peak hohlraum temperatures near 300 eV with overall backscatter less than 15%. Important national security and basic science experiments have also been conducted on NIF. Successful demonstration of ignition and net energy gain on NIF will be a major step towards demonstrating the feasibility of laser-driven Inertial Fusion Energy (IFE). This paper will describe the results achieved so far on the path toward ignition, the beginning of fundamental science experiments and the plans to transition NIF to an international user facility providing access to HEDS and fusion energy researchers around the world.

Moses, E. I.; Storm, E.

2013-11-01

190

Advanced Tokamak Physics and the Fusion Ignition Research Experiment (FIRE)  

Microsoft Academic Search

The advanced tokamak (AT) configuration for magnetic confinement of plasma is considered to have high potential for a viable fusion energy based power plant. The configuration operates at high beta (ratio of kinetic pressure to magnetic pressure) by avoiding and actively stabilizing plasma instabilities, with large self-driven plasma current, (bootstrap current, f_bs), to reduce the need for external current drive,

Charles Kessel; Dale Meade

2003-01-01

191

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

192

High field superconducting magnets (12 T and greater) for fusion applications  

SciTech Connect

The technology for producing high fields in large superconducting magnets has increased greatly in recent years, but must increase still more in the future. In this paper, we examine the present state of the art vis-a-vis the needs of a next-generation fusion machine and outline a program to provide for those needs. We also highlight recent developments that suggest the program goals are within reach.

Miller, J.R.; Summers, L.T.; Kerns, J.A.

1986-07-09

193

High speed plasma diagnostics for laser plasma interaction and fusion studies  

Microsoft Academic Search

Laser plasma interaction and fusion studies involve many high speed plasma diagnostics to determine the various parameters\\u000a for explaining the physical processes taking place in plasma. Detection and analysis of short-term or transient radiations\\u000a (X-ray and visible) are the bases for diagnosing the physical processes occurring during laser-plasma interaction or similar\\u000a radiation-emitting processes. This paper reviews the development of various

V N Rai; M Shukla; H C Pant; D D Bhawalkar

1999-01-01

194

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

Smer ?ahin; Mustafa beyli

2004-01-01

195

Potentiometric quasi-array employing calixarene derivatives for the high-throughput similarity/diversity screening of beta-adrenergic and beta-blocking chiral drugs by HPLC.  

PubMed

Performance of potentiometric quasi-array detection system consisted with the seven poly (vinyl chloride) (PVC) based liquid membrane electrodes in the cation-exchange HPLC using acetonitrile--40 mM phosphoric acid (15 : 85, v/v, pH* 2.35) for assessing of molecular similarity/diversity in a mini-library of beta-adrenergic and beta-blocking chiral drugs was presented. Macrocyclic compounds differing in stability of their conformers as well as in a size, steric hindrance and polarity of its internal cavities, comprising a series of five calix[6]arene derivatives completed with one modified calix[4]resorcinarene, were used as neutral ionophores to compose mentioned set of PVC-based electrodes. The output potentiometric responses were registered in the linear supernerstian range of calibration graph of each electrode, i.e. for a constant injected concentration 2.0 x 10(-4) M of investigated drugs, which is related to the amount frequently used at in vitro studies on pharmacological effects of these drugs. The impact of symmetry oriented supramolecular interactions on the responses of developed electrodes were characterised with proposed series of the highly significant quantitative structure-potentiometric response relationships (QSPRRs) combining both three-dimensional (3D) molecular descriptors of analysed drugs as well as lipophilicity and volume polarizability of calixarene-type ionophores. The principal components analysis (PCA) and unweighted hierarchical clustering analysis (HCA) were used as the pattern recognition techniques into collected potentiometric database for extraction of the useful information on the molecular and pharmacological similarity/diversity of analysed drugs, thus a high-throughput and consistent identification of therapeutically relevant agonists of beta2- and beta3-adrenoceptors and antagonists of beta1-adrenoceptor was especially achieved. This evidence supports also a hypothesis formulated by results of homology modelling on the subtle significance of an unrecognised supramolecular insertion processes of the chiral drug molecule into the flexible hydrophobic pocket(s) formed by seven helical transmembrane moving domains of beta-adrenoceptors on their final activation, sequestration, down-regulation or blockade. PMID:15200382

Bazylak, Grzegorz; Nagels, Luc J; Geise, Herman J

2004-06-01

196

High LET Radiation Can Enhance TGF(Beta) Induced EMT and Cross-Talk with ATM Pathways  

NASA Technical Reports Server (NTRS)

The TGF(Beta) pathway has been shown to regulate or directly interact with the ATM pathway in the response to radiation in mammary epithelial cells. We investigated possible interactions between the TGF(Beta) and ATM pathways following simulated space radiation using hTERT immortalized human esophageal epithelial cells (EPC-hTERT), mink lung epithelial cells (Mv1lu), and several human fibroblast cell lines. TGF(Beta) is a key modulator of the Epithelial-Mesenchymal Transition (EMT), important in cancer progression and metastasis. The implication of EMT by radiation also has several lines of developing evidence, however is poorly understood. The identification of TGF(Beta) induced EMT can be shown in changes to morphology, related gene over expression or down regulation, which can be detected by RT-PCR, and immunostaining and western blotting. In this study, we have observed morphologic and molecular alternations consistent with EMT after Mv1lu cells were treated with TGF(Beta) High LET radiation enhanced TGF(Beta) mediated EMT with a dose as low as 0.1Gy. In order to consider the TGF(Beta) interaction with ATM we used a potent ATM inhibitor Ku55933 and investigated gene expression changes and Smad signaling kinetics. Ku559933 was observed to reverse TGF(Beta) induced EMT, while this was not observed in dual treated cells (radiation+TGF(Beta)). In EPC-hTERT cells, TGF(Beta) alone was not able to induce EMT after 3 days of application. A combined treatment with high LET, however, significantly caused the alteration of EMT markers. To study the function of p53 in the process of EMT, we knocked down P53 through RNA interference. Morphology changes associated with EMT were observed in epithelial cells with silenced p53. Our study indicates: high LET radiation can enhance TGF(Beta) induced EMT; while ATM is triggering the process of TGF(Beta)-induced EMT, p53 might be an essential repressor for EMT phenotypes.

Wang, Minli; Hada, Megumi; Huff, Janice; Pluth, Janice M.; Anderson, Janniffer; ONeill, Peter; Cucinotta, Francis A.

2010-01-01

197

Prenatal diagnosis of beta-thalassemia major by high-performance liquid chromatography analysis of hemoglobins in fetal blood samples.  

PubMed

In Thailand and adjacent countries, most of the beta-thalassemia genes are beta(0)-thalassemia mutations that prevent the production of Hb A. We propose the quantitation of the Hb A fraction in fetal blood in the mid-trimester of pregnancy by automated high performance liquid chromatography as a reasonable prenatal diagnostic method to be applied in areas with limited laboratory facilities. Forty pregnant women at risk of delivering a child with beta-thalassemia major were identified using an erythrocyte osmotic fragility test and quantitation of Hb A2. Cordocentesis was performed at the gestational age of 18-22 weeks and fetal blood was analyzed for hemoglobin fractions by automated high performance liquid chromatography. The beta-globin gene mutations were characterized by beta-globin gene sequencing. The 4 bp deletion at codons 41/42 (-TTCT) was the most frequent of the 40 beta-thalassemia mutations observed (20/40 = 50%), followed by the splice site mutation IVS-I-1 (G-->T) (7/40 = 17.5%), the nonsense mutation at codon 17 (A-->T) (7/40 = 17.5%), the nonsense mutation at codon 35 (C-->A) (3/40 = 7.5%), and the beta(+)-thalassemia promoter mutation at -28 (A-->G) (3/40 = 7.5%). High performance liquid chromatography revealed nine fetuses which had only Hb F and no Hb A. All were homozygotes or compound heterozygotes for beta(0)-thalassemia mutations. In the remaining 31 fetuses, a Hb A peak was present in the chromatograms. One fetus with 0.5% Hb A was a compound heterozygote for the -28 (A-->G) and codons 41/42 (-TTCT) mutations. In the remaining 30 fetuses, the Hb A values ranged between 0.8 and 7.4%. Twenty of these, with a Hb A concentration of 1.82 +/- 0.49% (range 0.8-2.8%), were beta-thalassemia heterozygotes. The remaining 10 fetuses had Hb A values of 4.89 +/- 1.47% (range 2.9-7.4%) and normal beta-globin genes. The absence of Hb A in homozygotes or compound heterozygotes for beta(0)-thalassemia mutations and the presence of measurable amounts of Hb A in heterozygotes and normal homozygotes, permits the diagnosis of fetuses expected to develop postnatal beta-thalassemia major. PMID:11300346

Sanguansermsri, T; Thanarattanakorn, P; Steger, H F; Tongsong, T; Chanprapaph, P; Wanpirak, C; Siriwatanapa, P; Sirichotiyakul, S; Flatz, G

2001-02-01

198

The effect of beta-alanine supplementation on isokinetic force and cycling performance in highly trained cyclists.  

PubMed

Beta-alanine may benefit short-duration, high-intensity exercise performance. The aim of this randomized double-blind placebo-controlled study was to examine the effects of beta-alanine supplementation on aspects of muscular performance in highly trained cyclists. Sixteen highly trained cyclists (mean SD; age = 24 7 yr; mass = 70 7 kg; VO2max = 67 4 ml kg(-1) min(-1)) supplemented with either beta-alanine (n = 8, 65 mg kg - 1BM) or a placebo (n = 8; dextrose monohydrate) over 4 weeks. Pre- and postsupplementation cyclists performed a 4-minute maximal cycling test to measure average power and 30 reciprocal maximal isokinetic knee contractions at a fixed angular velocity of 180 sec(-1) to measure average power/repetition, total work done (TWD), and fatigue index (%). Blood pH, lactate (La-) and bicarbonate (HCO3-) concentrations were measured pre- and postisokinetic testing at baseline and following the supplementation period. Beta-alanine supplementation was 44% likely to increase average power output during the 4-minute cycling time trial when compared with the placebo, although this was not statistically significant (p = .25). Isokinetic average power/repetition was significantly increased post beta-alanine supplementation compared with placebo (beta-alanine: 6.8 9.9 W, placebo: -4.3 9.5 W, p = .04, 85% likely benefit), while fatigue index was significantly reduced (p = .03, 95% likely benefit). TWD was 89% likely to be improved following beta-alanine supplementation; however, this was not statistically significant (p = .09). There were no significant differences in blood pH, lactate, and HCO3- between groups (p > .05). Four weeks of beta-alanine supplementation resulted in worthwhile changes in time-trial performance and short-duration muscular force production in highly trained cyclists. PMID:23630052

Howe, Samuel T; Bellinger, Phillip M; Driller, Matthew W; Shing, Cecilia M; Fell, James W

2013-12-01

199

Characterization of cDNA of lycopene beta-cyclase responsible for a high level of beta-carotene accumulation in Dunaliella salina.  

PubMed

Lycopene beta-cyclase (Lyc-B) is the key enzyme in the catalysis of linear lycopene to form cyclic beta-carotene, an indispensable part of the photosynthetic apparatus and an important source of vitamin A in human and animal nutrition. Studies showing that the microalga Dunaliella salina can accumulate a high level of beta-carotene are lacking. We hypothesize that D. salina is closely involved with the catalytic mechanism of Lyc-B and the molecular regulation of its gene. In this study, we used RT-PCR and RACE-PCR to isolate a 2475 bp cDNA with a 1824 bp open reading frame, encoding a putative Lyc-B, from D. salina. Homology studies showed that the deduced amino acid sequence had a significant overall similarity with sequences of other green algae and higher plants, and that it shared the highest sequence identity, up to 64%, with Lyc-B of Chlamydomonas reinhardtii. Codon analysis showed that synonymous codon usage in the enzyme has a strong bias towards codons ending with adenosine. Two motifs were found in the Lyc-B sequence, one at the N terminus, for binding the hypothetical cofactor FAD, and the other was a substrate carrier motif in oxygenic organisms shared by an earlier carotenogenesis enzyme, phytoene desaturase, and Lyc-B. A tertiary structure prediction suggested that the catalytic or binding site structure within LycB from D. salina is superior to that of both H. pluvialis and C. reinhardtii. The LycB protein from D. salina was quite removed from that of H. pluvialis and C. reinhardtii in the phylogenetic tree. Taken as a whole, this information provides insight into the regulatatory mechanism of Lyc-B at the molecular level and the high level of beta-carotene accumulation in the microalga D. salina. PMID:18523490

Zhu, Yue-Hui; Jiang, Jian-Guo; Chen, Qian

2008-06-01

200

Non-inductive current drive and transport in high beta(N) plasmas in JET  

SciTech Connect

A route to stationary MHD stable operation at high beta(N) has been explored at the Joint European Torus (JET) by optimizing the current ramp-up, heating start time and the waveform of neutral beam injection (NBI) power. In these scenarios the current ramp-up has been accompanied by plasma pre-heat (or the NBI has been started before the current flat-top) and NBI power up to 22 MW has been applied during the current flat-top. In the discharges considered transient total beta(N) approximate to 3.3 and stationary (during high power phase) beta(N) approximate to 3 have been achieved by applying the feedback control of beta(N) with the NBI power in configurations with monotonic or flat core safety factor profile and without an internal transport barrier (ITB). The transport and current drive in this scenario is analysed here by using the TRANSP and ASTRA codes. The interpretative analysis performed with TRANSP shows that 50-70% of current is driven non-inductively; half of this current is due to the bootstrap current which has a broad profile since an ITB was deliberately avoided. The GLF23 transport model predicts the temperature profiles within a +/- 22% discrepancy with the measurements over the explored parameter space. Predictive simulations with this model show that the E x B rotational shear plays an important role for thermal ion transport in this scenario, producing up to a 40% increase of the ion temperature. By applying transport and current drive models validated in self-consistent simulations of given reference scenarios in a wider parameter space, the requirements for fully non-inductive stationary operation at JET are estimated. It is shown that the strong stiffness of the temperature profiles predicted by the GLF23 model restricts the bootstrap current at larger heating power. In this situation full non-inductive operation without an ITB can be rather expensive strongly relying on the external non-inductive current drive sources.

Voitsekhovitch, I [UKAEA Fusion, Culham UK; Alper, B. [EURATOM / UKAEA, UK; Brix, M [UKAEA Fusion, Culham UK; Budny, R. V. [Princeton Plasma Physics Laboratory (PPPL); Buratti, P. [ENEA, Frascati; Challis, C D [UKAEA Fusion, Culham UK; Ferron, J.R. [General Atomics, San Diego; Giroud, C. [EURATOM / UKAEA, UK; Joffrin, E. [CEA Cadarache, St. Paul lex Durance, France; Laborde, L. [UKAEA Fusion, Culham UK; Luce, T.C. [General Atomics, San Diego; McCune, D. [Princeton Plasma Physics Laboratory (PPPL); Menard, J. [Princeton Plasma Physics Laboratory (PPPL); Murakami, Masanori [ORNL; Park, Jin Myung [ORNL

2009-01-01

201

High performance manned interplanetary space vehicle using D-3He Inertial Electrostatic Fusion  

NASA Astrophysics Data System (ADS)

A preliminary system design is presented for a high performance 100 MWe manned space vehicle in the 500 metric ton class, based on Inertial Electrostatic Fusion (IEC), with trip times to the outer planets of several months. An IEC is chosen because it simplifies structure results in a very high power to weight ratio. The fusion reactor uses D-3He fuel which generates 14.7-MeV protons as the primary reaction product. The propulsion system design philosophy is based on direct conversion of proton energy to electricity, avoiding the thermalization of the working fluid to maximize efficiency. The principle system components of crew compartment, electronics, fusion reactor, traveling wave direct energy converter, step-down transformer, rectifier, ion thruster and heat rejection radiators are described. The design requires that an IEC reactor with a proton energy gain (power in 14.7-MeV protons/input electric power) of 4 or better is necessary to keep radiator mass and size at acceptable levels. Extrapolation of present laboratory scale IEC experiments to reactor relevant conditions is possible theoretically, but faces several open issues including stability under high-density conditions. Since unburned fusion fuels are recycled rather than exhausted with the propellant, problems of fuel weight and preservation of 3He are minimized. The 100-MWe propulsion system is based on NSTAR-extrapolated krypton ion thrusters operating at a specific impulse of 16,000 seconds and a total thrust of 1020 N. Thrust time for a typical outer planet mission ?V of 50,000 m/s is then ~200 days. .

Burton, R.; Momota, H.; Richardson, N.; Coventry, M.; Shaban, Y.; Miley, G. H.

2002-01-01

202

Highly efficient renaturation of beta-lactamase isolated from moderately halophilic bacteria.  

PubMed

Most, if not all, beta-lactamases reported to date are irreversibly denatured at 60-70 degrees C. Here, we found that a halophilic beta-lactamase from the moderately halophilic bacterium Chromohalobacter sp. 560 was highly stable against heat inactivation: it retained approximately 75% of its activity after boiling for 5 min in the presence of 0.2 M NaCl, suggesting that the protein either incompletely denatures during the boiling process or readily renatures upon cooling to the assay temperature. Circular dichroism showed a complete unfolding at 60 degrees C and a full reversibility, indicating that the observed activity after boiling is due to efficient refolding following heat denaturation. The enzyme showed optimal activity at 50-60 degrees C, indicating that an increase in activity with temperature offsets the thermal denaturation. The gene bla was cloned, and the primary structure of the enzyme was deduced to be highly abundant in acidic amino acid residues, one of the characteristics of halophilic proteins. Despite its halophilic nature, the enzyme refolds in low salt media after heat denaturation. PMID:14759507

Tokunaga, Hiroko; Ishibashi, Matsujiro; Arakawa, Tsutomu; Tokunaga, Masao

2004-01-30

203

Blind multichannel reconstruction of high-resolution images using wavelet fusion.  

PubMed

We developed an approach to the blind multichannel reconstruction of high-resolution images. This approach is based on breaking the image reconstruction problem into three consecutive steps: a blind multichannel restoration, a wavelet-based image fusion, and a maximum entropy image interpolation. The blind restoration step depends on estimating the two-dimensional (2-D) greatest common divisor (GCD) between each observation and a combinational image generated by a weighted averaging process of the available observations. The purpose of generating this combinational image is to get a new image with a higher signal-to-noise ratio and a blurring operator that is a coprime with all the blurring operators of the available observations. The 2-D GCD is then estimated between the new image and each observation, and thus the effect of noise on the estimation process is reduced. The multiple outputs of the restoration step are then applied to the image fusion step, which is based on wavelets. The objective of this step is to integrate the data obtained from each observation into a single image, which is then interpolated to give an enhanced resolution image. A maximum entropy algorithm is derived and used in interpolating the resulting image from the fusion step. Results show that the suggested blind image reconstruction approach succeeds in estimating a high-resolution image from noisy blurred observations in the case of relatively coprime unknown blurring operators. The required computation time of the suggested approach is moderate. PMID:16353806

El-Khamy, Said E; Hadhoud, Mohiy M; Dessouky, Moawad I; Salam, Bassiouny M; Abd-El-Samie, Fathi E

2005-12-01

204

Plasma Physics and Controlled Nuclear Fusion Research (Report on the 9th IAEA International Conference, Baltimore, 1982)  

Microsoft Academic Search

During the past decade of IAEA Conferences on controlled fusion research, the topic of principal interest has shifted from the feasibility of fusion power to the optimization of economically favourable reactor characteristics: efficient plasma heating systems, high beta values, quasi-steady-state operating capabilities, simple coil structures, etc. At the present Conference, the experimental tokamak papers (about half the total number of

H. P. Furth; B. B. Kadomtsev; C. Yamanaka; W. M. Lomer

1983-01-01

205

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

206

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

207

The Mercury Project: A High Average Power, Gas-Cooled Laser For Inertial Fusion Energy Development  

SciTech Connect

Hundred-joule, kilowatt-class lasers based on diode-pumped solid-state technologies, are being developed worldwide for laser-plasma interactions and as prototypes for fusion energy drivers. The goal of the Mercury Laser Project is to develop key technologies within an architectural framework that demonstrates basic building blocks for scaling to larger multi-kilojoule systems for inertial fusion energy (IFE) applications. Mercury has requirements that include: scalability to IFE beamlines, 10 Hz repetition rate, high efficiency, and 10{sup 9} shot reliability. The Mercury laser has operated continuously for several hours at 55 J and 10 Hz with fourteen 4 x 6 cm{sup 2} ytterbium doped strontium fluoroapatite (Yb:S-FAP) amplifier slabs pumped by eight 100 kW diode arrays. The 1047 nm fundamental wavelength was converted to 523 nm at 160 W average power with 73% conversion efficiency using yttrium calcium oxy-borate (YCOB).

Bayramian, A; Armstrong, P; Ault, E; Beach, R; Bibeau, C; Caird, J; Campbell, R; Chai, B; Dawson, J; Ebbers, C; Erlandson, A; Fei, Y; Freitas, B; Kent, R; Liao, Z; Ladran, T; Menapace, J; Molander, B; Payne, S; Peterson, N; Randles, M; Schaffers, K; Sutton, S; Tassano, J; Telford, S; Utterback, E

2006-11-03

208

Geographic information system for fusion and analysis of high-resolution remote sensing and ground truth data  

NASA Technical Reports Server (NTRS)

Viewgraphs on Geographic Information System for fusion and analysis of high-resolution remote sensing and ground truth data are presented. Topics covered include: scientific objectives; schedule; and Geographic Information System.

Freeman, Anthony; Dubois, Pascale; Leberl, Franz; Norikane, L.; Way, Jobea

1991-01-01

209

Universal antibodies against the highly conserved influenza fusion peptide cross-neutralize several subtypes of influenza A virus  

SciTech Connect

Research highlights: {yields} The fusion peptide is the only universally conserved epitope in all influenza viral hemagglutinins. {yields} Anti-fusion peptide antibodies are universal antibodies that cross-react with all influenza HA subtypes. {yields} The universal antibodies cross-neutralize different influenza A subtypes. {yields} The universal antibodies inhibit the fusion process between the viruses and the target cells. -- Abstract: The fusion peptide of influenza viral hemagglutinin plays a critical role in virus entry by facilitating membrane fusion between the virus and target cells. As the fusion peptide is the only universally conserved epitope in all influenza A and B viruses, it could be an attractive target for vaccine-induced immune responses. We previously reported that antibodies targeting the first 14 amino acids of the N-terminus of the fusion peptide could bind to virtually all influenza virus strains and quantify hemagglutinins in vaccines produced in embryonated eggs. Here we demonstrate that these universal antibodies bind to the viral hemagglutinins in native conformation presented in infected mammalian cell cultures and neutralize multiple subtypes of virus by inhibiting the pH-dependant fusion of viral and cellular membranes. These results suggest that this unique, highly-conserved linear sequence in viral hemagglutinin is exposed sufficiently to be attacked by the antibodies during the course of infection and merits further investigation because of potential importance in the protection against diverse strains of influenza viruses.

Hashem, Anwar M. [Centre for Vaccine Evaluation, Biologics and Genetic Therapies Directorate, HPFB, Health Canada, Ottawa, ON (Canada) [Centre for Vaccine Evaluation, Biologics and Genetic Therapies Directorate, HPFB, Health Canada, Ottawa, ON (Canada); Department of Microbiology, Faculty of Medicine, King Abdulaziz University, Jeddah (Saudi Arabia); Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON (Canada); Van Domselaar, Gary [National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB (Canada)] [National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB (Canada); Li, Changgui; Wang, Junzhi [National Institute for the Control of Pharmaceutical and Biological Products, Beijing (China)] [National Institute for the Control of Pharmaceutical and Biological Products, Beijing (China); She, Yi-Min; Cyr, Terry D. [Centre for Vaccine Evaluation, Biologics and Genetic Therapies Directorate, HPFB, Health Canada, Ottawa, ON (Canada)] [Centre for Vaccine Evaluation, Biologics and Genetic Therapies Directorate, HPFB, Health Canada, Ottawa, ON (Canada); Sui, Jianhua [Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Department of Medicine, Harvard Medical School, 44 Binney Street, Boston, MA 02115 (United States)] [Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Department of Medicine, Harvard Medical School, 44 Binney Street, Boston, MA 02115 (United States); He, Runtao [National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB (Canada)] [National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB (Canada); Marasco, Wayne A. [Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Department of Medicine, Harvard Medical School, 44 Binney Street, Boston, MA 02115 (United States)] [Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Department of Medicine, Harvard Medical School, 44 Binney Street, Boston, MA 02115 (United States); Li, Xuguang, E-mail: Sean.Li@hc-sc.gc.ca [Centre for Vaccine Evaluation, Biologics and Genetic Therapies Directorate, HPFB, Health Canada, Ottawa, ON (Canada) [Centre for Vaccine Evaluation, Biologics and Genetic Therapies Directorate, HPFB, Health Canada, Ottawa, ON (Canada); Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON (Canada)

2010-12-10

210

Heavy ion beam ICF fusion: The thermodynamics of ignition and the achievement of high gain in ICF fusion targets  

Microsoft Academic Search

A model suitable for the calculation of gain in a fuel tamped inertial confinement fusion (ICF) target is developed. The model can be applied to targets driven by any suitable driver, lasers, ion beams, etc. As an example it is applied to a particular single shell, multilayer heavy ion beam target.

K. A. Long; N. A. Tahir

1982-01-01

211

Evaluation of high strength, high conductivity CuNiBe alloys for fusion energy applications  

NASA Astrophysics Data System (ADS)

The unirradiated tensile properties for several different heats and thermomechanical treatment conditions of precipitation strengthened Hycon 3HP CuNiBe (Cu-2%Ni-0.35%Be in wt.%) have been measured over the temperature range of 20-500 C for longitudinal and long transverse orientations. The room temperature electrical conductivity has also been measured for several heats, and the precipitate microstructure was characterized using transmission electron microscopy. The CuNiBe alloys exhibit very good combination of strength and conductivity at room temperature, with yield strengths of 630-725 MPa and electrical conductivities of 65-72% International Annealed Copper Standard (IACS). The strength remained relatively high at all test temperatures, with yield strengths of 420-520 MPa at 500 C. However, low levels of ductility (<5% uniform elongation) were observed at test temperatures above 200-250 C, due to flow localization near grain boundaries (exacerbated by having only 10-20 grains across the gage thickness of the miniaturized sheet tensile specimens). Scanning electron microscopy observation of the fracture surfaces found a transition from ductile transgranular to ductile intergranular fracture with increasing test temperature. Fission neutron irradiation to a dose of ?0.7 displacements per atom (dpa) at temperatures between 100 and 240 C produced a slight increase in strength and a significant decrease in ductility. The measured tensile elongation after irradiation increased with increasing irradiation temperature, with a uniform elongation of ?3.3% observed at 240 C. The electrical conductivity decreased slightly following irradiation, due to the presence of defect clusters and Ni, Zn, Co transmutation products. Considering also previously published fracture toughness data, this indicates that CuNiBe alloys have irradiated tensile and electrical properties comparable or superior to CuCrZr and oxide dispersion strengthened copper at temperatures <250 C, and may be an attractive candidate for certain low-temperature fusion energy structural applications. Conversely, CuNiBe may not be preferred at intermediate temperatures of 250-500 C due to the poor ductility and fracture toughness of CuNiBe alloys at temperatures ?250 C. The potential deformation mechanisms responsible for the transition from transgranular to intergranular fracture are discussed. The possible implications for other precipitation-hardened alloys such as nickel based superalloys are briefly discussed.

Zinkle, S. J.

2014-06-01

212

Evaluation of high strength, high conductivity CuNiBe alloys for fusion energy applications  

SciTech Connect

The unirradiated tensile properties for several different heats and thermomechanical treatment conditions of precipitation strengthened Hycon 3HPTM CuNiBe (Cu-2%Ni-0.35%Be in wt.%) have been measured over the temperature range of 20-500 C for longitudinal and long transverse orientations. The room temperature electrical conductivity has also been measured for several heats, and the precipitate microstructure was characterized using transmission electron microscopy. The CuNiBe alloys exhibit very good combination of strength and conductivity at room temperature, with yield strengths of 630-725 MPa and electrical conductivities of 65-72% International Annealed Copper Standard (IACS). The strength remained relatively high at all test temperatures, with yield strengths of 420-520 MPa at 500 C. However, low levels of ductility (<5% uniform elongation) were observed at test temperatures above 200-250 C, due to flow localization near grain boundaries (exacerbated by having only 10-20 grains across the gage thickness of the miniaturized sheet tensile specimens). Scanning electron microscopy observation of the fracture surfaces found a transition from ductile transgranular to ductile intergranular fracture with increasing test temperature. Fission neutron irradiation to a dose of ~0.7 displacements per atom (dpa) at temperatures between 100 and 240 C produced a slight increase in strength and a significant decrease in ductility. The measured tensile elongation increased with increasing irradiation temperature, with a uniform elongation of ~3.3% observed at 240 C. The electrical conductivity decreased slightly following irradiation, due to the presence of defect clusters and Ni, Zn, Co transmutation products. Considering also previously published fracture toughness data, this indicates that CuNiBe alloys have irradiated tensile and electrical properties comparable or superior to CuCrZr and oxide dispersion strengthened copper at temperatures <250 C, and may be an attractive candidate for certain fusion energy structural applications. Conversely, CuNiBe may not be preferred at intermediate temperatures of 250-500 C due to the poor ductility and fracture toughness of CuNiBe alloys at temperatures >250 C. The potential deformation mechanisms responsible for the transition from transgranular to intergranular fracture are discussed. The possible implications for other precipitation hardened alloys such as nickel based superalloys are briefly discussed.

Zinkle, Steven J [ORNL] [ORNL

2014-01-01

213

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

214

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

215

Generating High-Brightness Light Ion Beams for Inertial Fusion Energy  

SciTech Connect

Light ion beams may be the best option for an Inertial Fusion Energy (IFE) driver from the standpoint of ei%ciency, standoff, rep-rate operation and cost. This approach uses high-energy-density pulsed power to efficiently accelerate ions in one or two stages at fields of 0.5 to 1.0 GV/m to produce a medium energy (30 MeV), high-current (1 MA) beam of light ions, such as lithium. Ion beams provide the ability for medium distance transport (4 m) of the ions to the target, and standofl of the driver from high- yield implosions. Rep-rate operation of' high current ion sources has ako been demonstrated for industrial applications and couId be applied to IFE. Although (hese factors make light ions the best Iong-teml pulsed- power approach to IFE, light-ion research is being suspended this year in favor of a Z-pinch-driven approach which has the best opport lnity to most-rapidly achieve the U.S. Department of Energy sponsor's goal of high-yield fusion. This paper will summarize the status and most recent results of the light-ion beam program at Sandia National Laboratories (SNL), and document the prospects of light ions for future IFE driver development.

Adams, R.G.; Bailey, J.E.; Cuneno, M.E.; Desjarlais, M.P.; Filuk, A.B.; Hanson, D.L.; Johnson, D.J.; Mehlohorn, T.A.; Menge, P.R.; Olson, C.L.; Pointon, T.D. Slutz, S.A.; Vesey, R.A.; Welch, D.R.; Wenger, D.F.

1998-10-22

216

Reusing information for high-level fusion: characterizing bias and uncertainty in human-generated intelligence  

NASA Astrophysics Data System (ADS)

To expedite the intelligence collection process, analysts reuse previously collected data. This poses the risk of analysis failure, because these data are biased in ways that the analyst may not know. Thus, these data may be incomplete, inconsistent or incorrect, have structural gaps and limitations, or simply be too old to accurately represent the current state of the world. Incorporating human-generated intelligence within the high-level fusion process enables the integration of hard (physical sensors) and soft information (human observations) to extend the ability of algorithms to associate and merge disparate pieces of information for a more holistic situational awareness picture. However, in order for high-level fusion systems to manage the uncertainty in soft information, a process needs to be developed for characterizing the sources of error and bias specific to human-generated intelligence and assessing the quality of this data. This paper outlines an approach Towards Integration of Data for unBiased Intelligence and Trust (TID-BIT) that implements a novel Hierarchical Bayesian Model for high-level situation modeling that allows the analyst to accurately reuse existing data collected for different intelligence requirements. TID-BIT constructs situational, semantic knowledge graphs that links the information extracted from unstructured sources to intelligence requirements and performs pattern matching over these attributed-network graphs for integrating information. By quantifying the reliability and credibility of human sources, TID-BIT enables the ability to estimate and account for uncertainty and bias that impact the high-level fusion process, resulting in improved situational awareness.

Burke, Dustin; Carlin, Alan; Picciano, Paul; Levchuk, Georgiy; Riordan, Brian

2013-05-01

217

Purification, characterization, and substrate specificity of a novel highly glucose-tolerant beta-glucosidase from Aspergillus oryzae.  

PubMed

Aspergillus oryzae was found to secrete two distinct beta-glucosidases when it was grown in liquid culture on various substrates. The major form had a molecular mass of 130 kDa and was highly inhibited by glucose. The minor form, which was induced most effectively on quercetin (3,3',4',5,7-pentahydroxyflavone)-rich medium, represented no more than 18% of total beta-glucosidase activity but exhibited a high tolerance to glucose inhibition. This highly glucose-tolerant beta-glucosidase (designated HGT-BG) was purified to homogeneity by ammonium sulfate precipitation, gel filtration, and anion-exchange chromatography. HGT-BG is a monomeric protein with an apparent molecular mass of 43 kDa and a pI of 4.2 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and isoelectric focusing polyacrylamide gel electrophoresis, respectively. Using p-nitrophenyl-beta-D-glucoside as the substrate, we found that the enzyme was optimally active at 50 degreesC and pH 5.0 and had a specific activity of 1,066 micromol min-1 mg of protein-1 and a Km of 0.55 mM under these conditions. The enzyme is particularly resistant to inhibition by glucose (Ki, 1. 36 M) or glucono-delta-lactone (Ki, 12.5 mM), another powerful beta-glucosidase inhibitor present in wine. A comparison of the enzyme activities on various glycosidic substrates indicated that HGT-BG is a broad-specificity type of fungal beta-glucosidase. It exhibits exoglucanase activity and hydrolyzes (1-->3)- and (1-->6)-beta-glucosidic linkages most effectively. This enzyme was able to release flavor compounds, such as geraniol, nerol, and linalol, from the corresponding monoterpenyl-beta-D-glucosides in a grape must (pH 2.9, 90 g of glucose liter-1). Other flavor precursors (benzyl- and 2-phenylethyl-beta-D-glucosides) and prunin (4',5,7-trihydroxyflavanone-7-glucoside), which contribute to the bitterness of citrus juices, are also substrates of the enzyme. Thus, this novel beta-glucosidase is of great potential interest in wine and fruit juice processing because it releases aromatic compounds from flavorless glucosidic precursors. PMID:9758774

Riou, C; Salmon, J M; Vallier, M J; Gnata, Z; Barre, P

1998-10-01

218

Water mobility in the endosperm of high beta-glucan barley mutants as studied by nuclear magnetic resonance imaging  

Microsoft Academic Search

1H NMR imaging (MRI) was used as a noninvasive technique to study water distribution and mobility in hydrated barley (Hordeum vulgare L.) seeds of accessions with varying content of beta glucan (BG), a highly hygroscopic cell wall component. High contents of BG in barley are unfavorable in malting where it leads to clotting of filters and hazing of beer as

Helene Fast Seefeldt; Frans van den Berg; Walter Kckenberger; Sren Balling Engelsen; Bernd Wollenweber

2007-01-01

219

High-temperature decomposition of solid solutions of beta-tantalum with copper in films  

NASA Astrophysics Data System (ADS)

Using high-temperature X-ray diffractometry and electron microprobe analysis decomposition of alloys of beta-tantalum with copper produced by codeposition of sputtered ultradisperse particles of tantalum and copper has been established. At a temperature of 900C, the precipitation of copper from the solid solution into an individual phase starts, and its diffusion onto the film surface with the formation of globular particles and simultaneous transition of the matrix ?-modification into ?-tantalum. The suggested mechanism of decomposition of solid solutions includes the following stages: the precipitation of copper into an individual phase, its diffusion onto the surface because of lattice pressure and the concentration gradient inside and outside the tantalum matrix, the coalescence of nanosized formations into drops at the coating surface, and the subsequent evaporation of copper from them in a vacuum.

Tuleushev, Yu. Zh.; Volodin, V. N.; Zhakanbaev, E. A.

2014-05-01

220

Fast magnetization of a high-to-low-beta plasma beam  

NASA Technical Reports Server (NTRS)

The magnetization of a high-beta (plasma energy density/magnetic-field energy density) hydrogen-plasma beam injected into a vacuum transverse magnetic field is studied experimentally. Nominal parameters were Ti = 1 eV, Te = 5 eV, n = 3 x 10 to the 13th/cu cm or less, v(i) = 7 x 10 to the 6th cm/sec or less, t(pulse) less than 70 microsec, and Bz = 300 G or less. Plasma characteristics were measured for a wide beam and a downstream distance, x = 300 rho(i) or less, where x is the downstream distance and rho(i) is the ion gyroradius. A brief initial state of diamagnetic propagation is observed, followed by magnetized propagation accompanied by beam compression transverse to 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.

Song, J. J.; Wessel, F. J.; Yur, G.; Rahman, H. U; Rostoker, N.

1990-01-01

221

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

222

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

NASA Technical Reports Server (NTRS)

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.

2003-01-01

223

Optimization of DIII-D advanced tokamak discharges with respect to the {beta} limit  

SciTech Connect

Results are presented from comparisons of modeling and experiment in studies to assess the best choices of safety factor q profile, pressure profile, and discharge shape for high {beta}, steady-state, noninductive advanced tokamak operation in the DIII-D device [J. L. Luxon, Nucl. Fusion 42, 614 (2002)]. These studies are motivated by the need for high q{sub min}{beta}{sub N} to maximize the self-driven bootstrap current while maintaining high toroidal {beta} to increase fusion gain. Modeling shows that increases in the normalized beta {beta}{sub N} stable to ideal, low toroidal mode number (n=1,2), instabilities can be obtained through broadening of the pressure profile and use of a symmetric double-null divertor shape. Experimental results are in agreement with this prediction. The general trend is for q{sub min}{beta}{sub N} to increase with the minimum q value (q{sub min}) although {beta}{sub N} decreases as q{sub min} increases. By broadening the pressure profile, {beta}{sub N}{approx_equal}4 is obtained with q{sub min}{approx_equal}2. Modeling of equilibria with near 100% bootstrap current indicates that operation with {beta}{sub N}{approx_equal}5 should be possible with a sufficiently broad pressure profile.

Ferron, J.R.; Casper, T.A.; Doyle, E.J. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); University of California-Los Angeles, Los Angeles, California 90024 (United States)] (and others)

2005-05-15

224

High resolution neutron diffraction crystallographic investigation of Oxide Dispersion Strengthened steels of interest for fusion technology  

NASA Astrophysics Data System (ADS)

High resolution neutron diffraction measurements have been carried out to characterize the crystallographic phases present in different Oxide Dispersion Strengthened (ODS) steels of interest for fusion technology. The different lattice structures, Im3m for the ferritic ODS and Fm3m for the austenitic ODS, are resolved showing line anisotropy effects possibly correlated with differences in dislocation densities and texture. Many contributions from minority phases are detected well above the background noise; none of the expected crystallographic phases, such as M23C6 and including Y2O3, fits them, but the TiN phase is identified in accordance with results of other microstructural techniques.

Coppola, R.; Rodriguez-Carvajal, J.; Wang, M.; Zhang, G.; Zhou, Z.

2014-12-01

225

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

226

High beta capture and mirror confinement of laser produced plasmas. Semiannual report, July 1, 1975January 31, 1976  

Microsoft Academic Search

The Laser Initiated Target Experiment (LITE) at the United Technologies Research Center is designed to address the target plasma buildup approach to a steady state mirror fusion device. A dense, mirror confined, target plasma is produced by high power laser irradiation of a solid lithium hydride particle, electrically suspended in a vacuum at the center of an established minimum-B magnetic

A. F. Haught; D. H. Polk; W. J. Fader; R. G. Tomlinson; R. A. Jong; W. B. Ard; A. E. Mensing; T. L. Churchill; J. H. Stufflebeam; F. J. Bresnock

1976-01-01

227

Eukaryotic beta-alanine synthases are functionally related but have a high degree of structural diversity.  

PubMed Central

beta-Alanine synthase (EC 3.5.1.6), which catalyzes the final step of pyrimidine catabolism, has only been characterized in mammals. A Saccharomyces kluyveri pyd3 mutant that is unable to grow on N-carbamyl-beta-alanine as the sole nitrogen source and exhibits diminished beta-alanine synthase activity was used to clone analogous genes from different eukaryotes. Putative PYD3 sequences from the yeast S. kluyveri, the slime mold Dictyostelium discoideum, and the fruit fly Drosophila melanogaster complemented the pyd3 defect. When the S. kluyveri PYD3 gene was expressed in S. cerevisiae, which has no pyrimidine catabolic pathway, it enabled growth on N-carbamyl-beta-alanine as the sole nitrogen source. The D. discoideum and D. melanogaster PYD3 gene products are similar to mammalian beta-alanine synthases. In contrast, the S. kluyveri protein is quite different from these and more similar to bacterial N-carbamyl amidohydrolases. All three beta-alanine synthases are to some degree related to various aspartate transcarbamylases, which catalyze the second step of the de novo pyrimidine biosynthetic pathway. PYD3 expression in yeast seems to be inducible by dihydrouracil and N-carbamyl-beta-alanine, but not by uracil. This work establishes S. kluyveri as a model organism for studying pyrimidine degradation and beta-alanine production in eukaryotes. PMID:11454750

Gojkovic, Z; Sandrini, M P; Piskur, J

2001-01-01

228

Beta-alanine supplementation reduces acidosis but not oxygen uptake response during high-intensity cycling exercise.  

PubMed

The oral ingestion of beta-alanine, the rate-limiting precursor in carnosine synthesis, has been shown to elevate the muscle carnosine content. Carnosine is thought to act as a physiologically relevant pH buffer during exercise but direct evidence is lacking. Acidosis has been hypothesised to influence oxygen uptake kinetics during high-intensity exercise. The present study aimed to investigate whether oral beta-alanine supplementation could reduce acidosis during high-intensity cycling and thereby affect oxygen uptake kinetics. 14 male physical education students participated in this placebo-controlled, double-blind study. Subjects were supplemented orally for 4 weeks with 4.8 g/day placebo or beta-alanine. Before and after supplementation, subjects performed a 6-min cycling exercise bout at an intensity of 50% of the difference between ventilatory threshold (VT) and VO(2peak). Capillary blood samples were taken for determination of pH, lactate, bicarbonate and base excess, and pulmonary oxygen uptake kinetics were determined with a bi-exponential model fitted to the averaged breath-by-breath data of three repetitions. Exercise-induced acidosis was significantly reduced following beta-alanine supplementation compared to placebo, without affecting blood lactate and bicarbonate concentrations. The time delay of the fast component (Td(1)) of the oxygen uptake kinetics was significantly reduced following beta-alanine supplementation compared to placebo, although this did not reduce oxygen deficit. The parameters of the slow component did not differ between groups. These results indicate that chronic beta-alanine supplementation, which presumably increased muscle carnosine content, can attenuate the fall in blood pH during high-intensity exercise. This may contribute to the ergogenic effect of the supplement found in some exercise modes. PMID:19841932

Baguet, Audrey; Koppo, Katrien; Pottier, Andries; Derave, Wim

2010-02-01

229

High resolution x-ray imaging microscope for diagnostics of inertial confinement fusion  

NASA Astrophysics Data System (ADS)

X-ray imaging technology is highly developed to meet the needs of high-energy physics and diagnostics of inertial confinement fusion. In this paper, we describe the design of a non coplanar torodal mirrors microscope. It consists of three off-axis revolution concave torodal mirrors working at grazing incidence. Non-periodic W/SiC multilayer coatings have been deposited on each mirror, in order to increase until 10 keV the bandpass of reflectivity of the microscope. These super mirrors have been designed to work at 0.6 grazing incidence angle and display a reflectivity better than 40% in the entire energy range 2-10 keV. Concerning the imaging performances, we have almost achieved 5 ?m of spatial resolution in a field of 500 ?m. Regarding to these results, this prototype of microscope, the so-called "Plasma Imageur X pour les Experiences Laser Mega Joule" (PIXEL), will be used for 2D spatial and 1D time resolved imaging of dense plasmas produced during inertial confinement fusion experiments at the future Laser Mega Joule French facility (LMJ).

Maury, Helene; Troussel, Philippe; Champeaux, J. P.

2009-08-01

230

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

231

Electron temperature profiles in high power neutral-beam-heated TFTR (Tokamak Fusion Test Reactor) plasmas  

SciTech Connect

In 1986, the maximum neutral beam injection (NBI) power in the Tokamak Fusion Test Reactor (TFTR) was increased to 20 MW, with three beams co-parallel and one counter-parallel to I/sub p/. TFTR was operated over a wide range of plasma parameters; 2.5 < q/sub cyl/ < 10, and 2 x 10/sup 19/ < anti n/sub e/ < 7 x 10/sup 19/ m/sup -3/. Data bases have been constructed with over 600 measured electron temperature profiles from multipoint TV Thomson scattering which span much of this parameter space. We have also examined electron temperature profile shapes from electron cyclotron emission at the fundamental ordinary mode and second harmonic extraordinary mode for a subset of these discharges. In the light of recent work on ''profile consistency'' we have analyzed these temperature profiles in the range 0.3 < (r/a) < 0.9 to determine if a profile shape exists which is insensitive to q/sub cyl/ and beam-heating profile. Data from both sides of the temperature profile (T/sub e/(R)) were mapped to magnetic flux surfaces (T/sub e/(r/a)). Although T/sub e/(r/a), in the region where 0.3 < r/a < 0.9 was found to be slightly broader at lower q/sub cyl/, it was found to be remarkably insensitive to ..beta../sub p/, to the fraction of NBI power injected co-parallel to I/sub p/, and to the heating profile going from peaked on axis, to hollow. 10 refs., 8 figs.

Taylor, G.; Grek, B.; Stauffer, F.J.; Goldston, R.J.; Fredrickson, E.D.; Wieland, R.M.; Zarnstorff, M.C.

1987-09-01

232

Base-catalyzed highly stereoselective conversion of gamma-hydroxy-alpha,beta-acetylenic esters to gamma-acetoxy dienoates.  

PubMed

Gamma-hydroxy-alpha,beta-acetylenic esters can be conveniently prepared from the reaction of methyl propiolate with aldehydes in the presence of ZnEt(2) and N-methylimidazole at room temperature. It is discovered that the gamma-hydroxy-alpha,beta-acetylenic esters can be catalyzed by p-N,N-dimethylaminopyridine (DMAP) in acetic anhydride to generate the gamma-acetoxy dienoates with high stereo control. The mechanism of this conversion is investigated by NMR analyses and isotope labeling experiments. An intramolecular Diels-Alder reaction of a gamma-acetoxy dienoate is conducted to show the synthetic potential of these compounds. PMID:19322771

Yue, Yang; Yu, Xiao-Qi; Pu, Lin

2009-01-01

233

Resorbability of rigid beta-tricalcium phosphate wedges in open-wedge high tibial osteotomy: A retrospective radiological study  

Microsoft Academic Search

The open-wedge high tibial osteotomy (OWHTO) is a well accepted treatment modality for patients with osteoarthritis of the medial compartment associated with genu varum. To fill in the osteotomy gap 30% macroporosity rigid beta-tricalcium phosphate (?-TCP) is frequently used as a stable resorbable bone substitute. However, the resorbability of these ?-TCP wedges is not known. The aim of this study

T. Kraal; M. Mullender; J. H. D. de Bruine; R. Reinhard; A. de Gast; D. J. Kuik; B. J. van Royen

2008-01-01

234

The proximal promoter of the bovine luteinizing hormone beta-subunit gene confers gonadotrope-specific expression and regulation by gonadotropin-releasing hormone, testosterone, and 17 beta-estradiol in transgenic mice.  

PubMed

Transient transfection studies have proven useful in unraveling the molecular mechanisms underlying gonadotrope-specific expression and hormonal regulation of the gene encoding the alpha-subunit of the glycoprotein hormones. In contrast, similar studies performed with the LH beta gene have been less informative. When assayed by transient transfection into alpha T3-1 cells, activity of a 776-basepair bovine LH beta promoter-chloramphenicol acetyltransferase fusion gene (bLH beta CAT) was no greater than that of a promoterless control. To determine whether limited activity in vitro reflected the absence of critical regulatory elements, we examined activity of bovine LH beta fusion genes after stable integration in transgenic mice. In contrast to transient transfection studies, the LH beta promoter targeted high levels of CAT expression specifically to the pituitary. In addition, a bLH beta TK fusion gene was active only in gonadotropes. The bLH beta CAT transgene was also evaluated for responsiveness to gonadal steroids and GnRH. Testosterone and 17 beta-estradiol were capable of suppressing activity 70-80% in castrated males, despite the absence of high affinity binding sites for androgen or estrogen receptors. This suggests that feedback inhibition of LH beta CAT transgene expression by gonadal steroids may occur through an indirect mechanism, possibly at the level of the hypothalamus. To address whether the bLH beta CAT transgene could be regulated by GnRH, we treated ovariectomized females with antide, a GnRH antagonist. Antide suppressed transgene activity by 60%. Thus, the proximal promoter of the bovine LH beta subunit gene directs appropriate patterns of cell-specific expression and retains responsiveness to gonadal steroids and GnRH. In light of the robust activity of the LH beta promoter in transgenic mice, we suggest that this animal model can be exploited further to dissect the complex mechanisms that underlie gonadotrope-specific expression and hormonal regulation of the LH beta gene. PMID:7708066

Keri, R A; Wolfe, M W; Saunders, T L; Anderson, I; Kendall, S K; Wagner, T; Yeung, J; Gorski, J; Nett, T M; Camper, S A

1994-12-01

235

The Cytotoxic Role of Intermittent High Glucose on Apoptosis and Cell Viability in Pancreatic Beta Cells  

PubMed Central

Objectives. Glucose fluctuations are both strong predictor of diabetic complications and crucial factor for beta cell damages. Here we investigated the effect of intermittent high glucose (IHG) on both cell apoptosis and proliferation activity in INS-1 cells and the potential mechanisms. Methods. Cells were treated with normal glucose (5.5?mmol/L), constant high glucose (CHG) (25?mmol/L), and IHG (rotation per 24?h in 11.1 or 25?mmol/L) for 7 days. Reactive oxygen species (ROS), xanthine oxidase (XOD) level, apoptosis, cell viability, cell cycle, and expression of cyclinD1, p21, p27, and Skp2 were determined. Results. We found that IHG induced more significant apoptosis than CHG and normal glucose; intracellular ROS and XOD levels were more markedly increased in cells exposed to IHG. Cells treated with IHG showed significant decreased cell viability and increased cell proportion in G0/G1 phase. Cell cycle related proteins such as cyclinD1 and Skp2 were decreased significantly, but expressions of p27 and p21 were increased markedly. Conclusions. This study suggested that IHG plays a more toxic effect including both apoptosis-inducing and antiproliferative effects on INS-1 cells. Excessive activation of cellular stress and regulation of cyclins might be potential mechanism of impairment in INS-1 cells induced by IHG. PMID:24772447

Zhang, Zhen; Li, Jing; Yang, Lei; Chen, Rongping; Yang, Rui; Zhang, Hua; Cai, Dehong; Chen, Hong

2014-01-01

236

Modelling of Sigma Scorpii, a high-mass binary with a Beta Cep variable primary component  

E-print Network

High-mass binary stars are known to show an unexplained discrepancy between the dynamical masses of the individual components and those predicted by models. In this work, we study Sigma Scorpii, a double-lined spectroscopic binary system consisting of two B-type stars residing in an eccentric orbit. The more massive primary component is a Beta Cep-type pulsating variable star. Our analysis is based on a time-series of some 1000 high-resolution spectra collected with the CORALIE spectrograph in 2006, 2007, and 2008. We use two different approaches to determine the orbital parameters of the star; the spectral disentangling technique is used to separate the spectral contributions of the individual components in the composite spectra. The non-LTE based spectrum analysis of the disentangled spectra reveals two stars of similar spectral type and atmospheric chemical composition. Combined with the orbital inclination angle estimate found in the literature, our orbital elements allow a mass estimate of 14.7 +/- 4.5 a...

Tkachenko, A; Pavlovski, K; Degroote, P; Papics, P I; Moravveji, E; Lehmann, H; Kolbas, V; Clemer, K

2014-01-01

237

Radio-Frequency Wave Excitation and Damping on a High Beta Plasma Column.  

NASA Astrophysics Data System (ADS)

Azimuthally symmetric (m = 0) radio-frequency (RF) waves for zero and for finite axial wave number k(,z) are investigated on the High-Beta Q Machine, a two-meter, 20 cm-diameter, low-compression linear theta pinch (T (GREATERTHEQ) 200 eV, n (DBLTURN) 10('15)cm('-3)) fast rising (0.4 (mu)s) compression field. The (k(,z) = 0) modes occur spontaneously following the implosion phase of the discharge. A novel 100-MWatt, 1 to 1.3-MHz, short wavelength current drive excites the plasma column in the vicinity of the lowest fast magnetoacoustic mode at various filling pressures. This current drive is designed as an integral part of the compression coil, which is segmented with a 20-cm axial wavelength (k(,z) = 0.314 cm('-1)). The electron density oscillations along major and minor chords at various positions are measured by interferometry perpendicular to the pinch axis. The oscillatory radial magnetic field component between pinch wall and hot plasma edge is measured by probes. Phases, amplitudes and radial mode structure are studied for the free (k = 0) modes and the externally driven (k (NOT=) 0) modes for various filling pressures of deuterium. In the first case, the damping is determined from the e-folding time of the decaying oscillations. In the latter case, the phases and amplitudes indicate a broad resonance structure, from which we extract the damping constant. The energy deposition from the externally driven RF wave leads to a radial expansion of the plasma column, as observed by axial interferometry and by excluded flux measurements. We compare these experimental results with damping phenomena as predicted by MHD-like collisional (viscous) and collisionless (ion-Landau and cyclotron) damping models. It is found that the viscous model overestimates the observed (k = 0) damping by at least an order of magnitude, while both the viscous and kinetic models underestimate the (k (NOT=) 0) damping by at least an order of magnitude. The characteristic and resonant frequencies, as well as the oscillatory radial mode structure, can be understood within the ideal MHD description. The experimentally observed damping and wave-energy deposition are consistent with the magnitude of the density oscillations. The efficiency of the RF energy deposition is at least 27%, somewhat exceeding that observed in other high-beta magnetoacoustic experiments.

Meuth, Hermann

238

A high statistics study of the beta-function in the SU(2) lattice thermodynamics  

E-print Network

The beta-function is investigated on the lattice in SU(2) gluodynamics. It is determined within a scaling hypothesis while a lattice size fixed to be taken into account. The functions calculated are compared with the ones obtained in the continuum limit. Graphics processing units (GPU) are used as a computing platform that allows gathering a huge amount of statistical data. Numerous beta-functions are analyzed for various lattices. The coincidence of the lattice beta-function and the analytical expression in the region of the phase transition is shown. New method for estimating a critical coupling value is proposed.

S. S. Antropov; O. A. Mogilevsky; V. V. Skalozub

2013-12-09

239

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

240

High dynamic range imaging on mobile devices using fusion of multiexposure images  

NASA Astrophysics Data System (ADS)

Because the real world scenes have a high dynamic range which exceeds the range of the imaging devices, the captured images sometimes contain under-exposed and saturated regions. In this paper, we propose a simple but effective method to achieve high dynamic range (HDR) rendering results from three multiexposure images comprising under-, normal-, and over-exposure. First, we generate the weight function, for the fusion of multiexposure images, according to the brightness. Then, we employ the bilateral filter-based retouching to enhance image details, especially in the dark regions. Experimental results demonstrate that the proposed method produces clear details in images and achieves natural HDR rendering results on mobile imaging devices.

Jung, Cheolkon; Yang, Yanru; Jiao, Licheng

2013-10-01

241

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

242

Synthesis of highly potent second-generation taxoids through effective kinetic resolution coupling of racemic beta-lactams with baccatins.  

PubMed

A series of highly potent second-generation taxoids bearing a 2-methylprop-1-enyl or a 2-methylpropyl group at C-3' with modifications at the C-2, C-10, and C-14 positions was synthesized through the coupling of racemic cis-beta-lactams with properly protected/modified baccatin and 14-OH-baccatin. A high level of kinetic resolution was observed for all cases examined. The observed highly efficient enantiomer differentiation is ascribed to the markedly different chiral environment between the (+)- and (-)-beta-lactams in their approach to the chiral framework of the enantiopure lithium alkoxide of a baccatin in the ring-opening coupling process. It was also observed that substantially higher selectivity was achieved when 14-OH-baccatin-1,14-carbonate was used. Analysis of the transition state models revealed that the repulsive interactions between the 3-TIPS group of a (-)-beta-lactam with 1, 14-carbonate group of the baccatin substantially increases the asymmetric bias in the kinetic resolution process, favoring the reaction of a (+)-beta-lactam, which leads to the observed excellent selectivity. PMID:10824166

Lin, S; Geng, X; Qu, C; Tynebor, R; Gallagher, D J; Pollina, E; Rutter, J; Ojima, I

2000-06-01

243

Plasma transport control and self-sustaining fusion reactor  

Microsoft Academic Search

The possibility of a high-performance\\/low-cost fusion reactor concept which can simultaneously satisfy (1) high beta, (2) high bootstrap fractio (self-sustaining) and (3) high confinement is discussed. In CDX-U, a tokamak configuration was created and sustained solely by internally generated bootstrap currents, in which a 'seed' current is created through a nonclassical current diffusion process. Recent theoretical studies of MHD stability

M. Ono; R. Bell; W. Choe; C. S. Chang; C. B. Forest; R. Goldston; Y. S. Hwang; S. C. Jardin; R. Kaita; S. Kaye; C. E. Kessel; H. Kugel; B. LeBlanc; J. Manickam; J. E. Menard; T. Munsat; M. Okabayashi; M. Peng; S. Sesnic; W. Tighe

1997-01-01

244

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

245

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

246

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

247

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

248

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

249

High-resolution measurement of the He-[beta] spectra of heliumlike chromium for possible diagnostic of laser-produced plasmas  

SciTech Connect

High-resolution He-[beta] spectra of heliumlike chromium have been recorded in an effort to provide accurate atomic data useful for the development of diagnostics of the electron temperature and density for laser-produced plasmas. The He-[beta] spectra are of particular interest for these very-high-density plasmas ([ital n][sub [ital e

Decaux, V.; Beiersdorfer, P.; Elliott, S.; Osterheld, A. (Lawrence Livermore National Laboratory, University of California, Livermore, California 94551 (United States)); Clothiaux, E. (Department of Physics, Auburn University, Auburn, Alabama 36849 (United States))

1995-01-01

250

Spinal fusion  

MedlinePLUS

Vertebral interbody fusion; Posterior spinal fusion; Arthrodesis; Anterior spinal fusion; Spine surgery - spinal fusion ... Spinal fusion is most often done along with other surgical procedures of the spine. It may be done: With ...

251

Stability Analysis of Resistive Wall Mode in Rotating High-beta Plasmas in DIII-D  

NASA Astrophysics Data System (ADS)

Stability of resistive wall modes (RWM) in rotating high beta DIII-D discharges is analyzed using the MARS-F code. The modes are calculated in axisymmetric toroidal equilibrium using the MHD plasma model with kinetic damping effects. RWM are analyzed for different spacing between the resistive wall and the plasma boundary and for different toroidal rotation profiles. Sensitivity study of the mode's stability on the plasma edge q-profile is made by varying both the edge current profile and the proximity of the plasma boundary to the real X-point geometry. The importance of the edge modeling on accurate RWM stability analysis is revisited. Scans of the mode's growth rate and frequency are made in these settings, and the mode's structure is explored. Quasilinear toroidal torque driven by jxB force due to current and magnetic field perturbations in the RWM is estimated and compared with the experimental estimate of the total toroidal torque on plasma. The dependencies of the RWM growth rate and frequency on the stability and torque parameters are presented.

Svidzinski, V. A.; in, Y.; Kim, J. S.; Chu, M. S.; Liu, Y. Q.

2011-11-01

252

High-beta plasma effects in a low-pressure helicon plasma  

SciTech Connect

In this work, high-beta plasma effects are investigated in a low-pressure helicon plasma source attached to a large volume diffusion chamber. When operating above an input power of 900 W and a magnetic field of 30 G a narrow column of bright blue light (due to Ar II radiation) is observed along the axis of the diffusion chamber. With this blue mode, the plasma density is axially very uniform in the diffusion chamber; however, the radial profiles are not, suggesting that a large diamagnetic current might be induced. The diamagnetic behavior of the plasma has been investigated by measuring the temporal evolution of the magnetic field (B{sub z}) and the plasma kinetic pressure when operating in a pulsed discharge mode. It is found that although the electron pressure can exceed the magnetic field pressure by a factor of 2, a complete expulsion of the magnetic field from the plasma interior is not observed. In fact, under our operating conditions with magnetized ions, the maximum diamagnetism observed is {approx}2%. It is observed that the magnetic field displays the strongest change at the plasma centre, which corresponds to the maximum in the plasma kinetic pressure. These results suggest that the magnetic field diffuses into the plasma sufficiently quickly that on a long time scale only a slight perturbation of the magnetic field is ever observed.

Corr, C. S.; Boswell, R. W. [Space Plasma, Power and Propulsion Group (SP3), Research School of Physical Science and Engineering, Australian National University, Canberra ACT 0200 (Australia)

2007-12-15

253

Prediction of parallel in-register amyloidogenic beta-structures In highly beta-rich protein sequences by pairwise propensity analysis  

E-print Network

Amyloids and prion proteins are clinically and biologically important beta-structures, whose supersecondary structures are difficult to determine by standard experimental or computational means. In addition, significant ...

Bryan, Allen Wayne

2009-01-01

254

Review of fusion synfuels  

SciTech Connect

Thermonuclear fusion offers an inexhaustible source of energy for the production of hydrogen from water. Depending on design, electric generation efficiencies of approx. 40 to 60% and hydrogen production efficiencies by high-temperature electrolysis of approx. 50 to 65% are projected for fusion reactors using high-temperatures blankets. Fusion/coal symbiotic systems appear economically promising for the first generation of commercial fusion synfuels plants. Coal production requirements and the environmental effects of large-scale coal usage would be greatly reduced by a fusion/coal system. In the long term, there could be a gradual transition to an inexhaustible energy system based solely on fusion.

Fillo, J.A.

1980-01-01

255

Reduced crying in term infants fed high beta-palmitate formula: a double-blind randomized clinical trial  

PubMed Central

Background Beta-palmitate (sn-2 palmitate) mimics human milk fat, enabling easier digestion. Therefore, we hypothesized that infants consuming high beta-palmitate formula would have more frequent, softer stools and reduced crying compared to infants consuming low beta-palmitate formula. Methods Formula-fed infants were randomly assigned to receive either (1) formula with high beta-palmitate (HBP, n?=?21) or (2) regular formula with a standard vegetable oil mix (LBP, n?=?21). A matched group of breastfed infants served as a reference (BF, n?=?21). Crying and stool characteristics data were recorded by the parents for 3days before the 6- and 12-week visits. Results We found no significant differences in the stool frequency or consistency between the two formula groups. The percentage of crying infants in the LBP group was significantly higher than that in the HBP and BF groups during the evening at 6weeks (88.2% vs. 56.3% and 55.6%, p?high beta-palmitate formula affects infant crying patterns during the first weeks of life. Comparable to breastfeeding, it reduced crying duration and frequency, primarily during the afternoon and evening hours, thereby improving the well-being of formula-fed infants and their parents. Trial registration NCT00874068. Registration date March 31, 2009 PMID:24942975

2014-01-01

256

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

257

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

258

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

259

High-temperature fusion of nitrogen compounds at laser influence on refractory metals  

NASA Astrophysics Data System (ADS)

The processes of laser burning and ignition on the surface of refractory metal (such as Zr, Ni, Hf) are researched in this paper. The regime of gas phase limit, at which the metal heating leads to the high temperature fusion of nitrogen compounds on their surface under condition Plimit. P has been performed, and it leads only to the creation of oxide compounds at Plimit. < P. It is shown that nitrogen creation has been a sharp appearance of new phase in the target heating dynamics. It is possible that its diagnostic as a non-stable metal burning product in the air could be done by optical method registration of non- monotonous changing of reflect capability R of the foliated system 'metal - oxide'.

Arzuov, M. A.; Gaynullin, B. I.; Ubaidullaev, S. A.

2002-04-01

260

Direct Drive Heavy-Ion-Beam Inertial Fusion at High Coupling Efficiency  

SciTech Connect

Issues with coupling efficiency, beam illumination symmetry and Rayleigh Taylor (RT) 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 ICF target physics code shows the ion range increasing four-fold 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. Grant; Logan, B. Grant; Perkins, L.J.; Barnard, J.J.

2007-06-25

261

Progress on the High Current Experiment for Heavy-Ion Fusion  

NASA Astrophysics Data System (ADS)

The High Current Experiment has been designed to test transport issues near the low energy end of a typical induction linac driver for Heavy Ion Fusion. The experiment is being assembled in phases and employs a single coasting beam characteristic of recent conceptual design drivers. A major goal of the experiment is the evaluation of the maximum acceptable aperture filling factor and transverse phase space evolution, as influenced by the initial state distribution function, beam steering and quadrupole alignment sensitivity, envelope mismatch, halo, and secondary electrons. A thorough measurement, within the limits of the diagnostics available, of the beam distribution function produced by the injector and matching section will be presented along with early commissioning results from the electrostatic transport quadrupoles and diagnostics.

Prost, Lionel; Ahle, L.; Celata, C.; Haber, I.; Lund, S.; Bienosek, F.; Franks, M.; Henestroza, E.; Karpenko, V.; Kwan, J.; Seidl, P.; Waldron, W.

2001-10-01

262

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

263

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. PMID:23297698

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

2013-01-01

264

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. PMID:24086660

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

2013-01-01

265

Fission Thrust sail as booster for high {\\Delta}v fusion based propulsion  

E-print Network

The fission thrust sail as booster for nuclear fusion-based rocket propulsion for future starships is studied. Some required aspects of these systems such as neutron moderation and sail regeneration are discussed. First order calculations are used together with Monte Carlo simulations to assess system performance. When the fusion rocket has relatively low efficiency (~30%) in converting fusion fuel to a directed exhaust, adding a fission sail is shown to be beneficial for obtainable delta-v. Also, this type of fission-fusion hybrid interstellar propulsion has the potential to improve acceleration. Other advantages are discussed as well.

Ceyssens, Frederik; Driesen, Maarten

2014-01-01

266

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

267

Combined inhalation of beta2 -agonists improves swim ergometer sprint performance but not high-intensity swim performance.  

PubMed

There is a high prevalence of asthma and airway hyperresponsiveness (AHR) in elite athletes, which leads to a major use of beta2 -agonists. In a randomized double-blinded crossover study, we investigated the effects of combined inhalation of beta2 -agonists (salbutamol, formoterol, and salmeterol), in permitted doses within the World Anti-Doping Agency 2013 prohibited list, in elite swimmers with (AHR, n?=?13) or without (non-AHR, n?=?17) AHR. Maximal voluntary isometric contraction of m. quadriceps (MVC), sprint performance on a swim ergometer and performance in an exhaustive swim test at 110% of VO2max were determined. Venous plasma interleukin-6 (IL-6) and interleukin-8 (IL-8) were measured post-exercise. No improvement was observed in the exhaustive swim test, but swim ergometer sprint time was improved (P?beta2 -agonists in both groups, whereas IL-8 only increased in AHR. In summary, inhalation of beta2 -agonists, in permitted doses, did not improve swim performance in elite swimmers. However, swim ergometer sprint performance and MVC were increased, which should be considered when making future anti-doping regulations. PMID:23834392

Kalsen, A; Hostrup, M; Bangsbo, J; Backer, V

2014-10-01

268

Real-time detection of single-living pancreatic beta-cell by laser tweezers Raman spectroscopy: high glucose stimulation.  

PubMed

Glucose acts as a beta-cell stimulus factor and leads to cellular responses that involve a large amount of biomolecule formation, relocation, and transformation. We hypothesize that information about these changes can be obtained in real-time by laser tweezers Raman spectroscopy. To test this hypothesis, repeated measurements designs in accordance with the application of Raman spectroscopy detection were used in the current experiment. Single rat beta-cells were measured by Raman spectroscopy in 2.8 mmol/l glucose culture medium as a basal condition. After stimulation with high glucose (20 mmol/l), the same cells were measured continuously. Each cell was monitored over a total time span of 25 min, in 5 min intervals. During this period of time, cells were maintained at an appropriate temperature controlled by an automatic heater, to provide near-physiological conditions. It was found that some significant spectral changes induced by glucose were taking place during the stimulation time course. The most noticeable changes were the increase of spectral intensity at the 1002, 1085, 1445, and 1655 cm(-1) peaks, mainly corresponding to protein and lipid. We speculate that these changes might have to do with beta-cell protein and lipid synthesis. Using laser tweezers Raman spectroscopy in combination with glucose stimulation, optical spectral information from rat beta-cells was received and analyzed. PMID:20091674

Rong, Xi; Huang, Shu-Shi; Kuang, Xiao-Cong; Liu, Hong

2010-07-01

269

Different pituitary. beta. -endorphin and adrenal cortisol response to ethanol in individuals with high and low risk for future development of alcoholism  

SciTech Connect

The purpose of the present studies was to investigate the activity of the adrenal gland and the pituitary {beta}-endorphin system in individuals from families with a 3 generation history of alcoholism, High Risk group, or from families without history of alcoholism, Low Risk group. On the day of testing, blood sample was taken at 9:00 a.m., then the subject drank a placebo drink or an ethanol solution. Additional blood samples were taken at 15, 45 and 120 minutes post-drink. Results indicated that individuals of the High Risk group had lower basal levels of {beta}-endorphin like immunoreactivity ({beta}-EPLIR) than individuals of the Low Risk group. The dose of 0.5 g ethanol/kg B.Wt. induced an induce an increase in the plasma content of {beta}-EPLIR of the High Risk group, but not of the Low Risk group. In the Low Risk group ethanol did not induce an increase above the 9:00 a.m. levels, however, it attenuated the {beta}-endorphin decrease overtime, observed following the placebo drink. Analysis of {beta}-endorphin-like peptides in the plasma of the High Risk group, with Sephadex G-75 chromatography indicated that the major component of the plasma {beta}-EPLIR was {beta}-lipotropin. Plasma cortisol levels, following ethanol intake, presented a small increase in the High Risk group but not in the Low Risk group.

Gianoulakis, C.G.; Beliveau, D.; Angelogianni, P.; Meaney, M.; Thavundayil, J.; Tawar, V.; Dumas, M. (McGill Univ., Quebec (Canada))

1989-01-01

270

The highs and lows of beta activity in cortico-basal ganglia loops.  

PubMed

Oscillatory activity in the beta (13-30Hz) frequency band is widespread in cortico-basal ganglia circuits, and becomes prominent in Parkinson's disease (PD). Here we develop the hypothesis that the degree of synchronization in this frequency band is a critical factor in gating computation across a population of neurons, with increases in beta band synchrony entailing a loss of information-coding space and hence computational capacity. Task and context drive this dynamic gating, so that for each state there will be an optimal level of network synchrony, and levels lower or higher than this will impair behavioural performance. Thus, both the pathological exaggeration of synchrony, as observed in PD, and the ability of interventions like deep brain stimulation (DBS) to excessively suppress synchrony can potentially lead to impairments in behavioural performance. Indeed, under physiological conditions, the manipulation of computational capacity by beta activity may itself present a mechanism of action selection and maintenance. PMID:24890470

Brittain, John-Stuart; Sharott, Andrew; Brown, Peter

2014-06-01

271

Cysteines Flanking the Internal Fusion Peptide Are Required for the Avian Sarcoma\\/Leukosis Virus Glycoprotein To Mediate the Lipid Mixing Stage of Fusion with High Efficiency  

Microsoft Academic Search

We previously showed that the cysteines flanking the internal fusion peptide of the avian sarcoma\\/leukosis virus subtype A (ASLV-A) Env (EnvA) are important for infectivity and cell-cell fusion. Here we define the stage of fusion at which the cysteines are required. The flanking cysteines are dispensable for receptor-triggered membrane association but are required for the lipid mixing step of fusion,

Sue E. Delos; Matthew B. Brecher; Zaoying Chen; Deborah C. Melder; Mark J. Federspiel; Judith M. White

2008-01-01

272

Co-existence of whistler waves with kinetic Alfven wave turbulence for the high-beta solar wind plasma  

SciTech Connect

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. As whistlers propagate through the inhomogeneous solar wind, the perpendicular wave number increases through refraction, increasing the Landau damping rate. However, the whistlers can survive because the background kinetic Alfven wave (KAW) turbulence creates a plateau by quasilinear (QL) diffusion in the solar wind electron distribution at small velocities. It is found that for whistler energy density of only {approx}10{sup -3} that of the kinetic Alfven waves, the quasilinear diffusion rate due to whistlers is comparable to KAW. Thus, very small amplitude whistler turbulence can have a significant consequence on the evolution of the solar wind electron distribution function.

Mithaiwala, Manish; Crabtree, Chris; Ganguli, Gurudas [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375-5346 (United States); Rudakov, Leonid [Icarus Research Inc., P.O. Box 30780, Bethesda, Maryland 20824-0780 (United States)

2012-10-15

273

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

274

Tests of local transport theory and reduced wall impurity influx with highly radiative plasmas in the Tokamak Fusion Test Reactor  

E-print Network

1 Tests of local transport theory and reduced wall impurity influx with highly radiative plasmas Laboratory, P. O. Box 451, Princeton, NJ 08543 Abstract The electron temperature (Te) profile in neutral beam in the Tokamak Fusion Test Reactor (TFTR) [K. M. McGuire et al.., Phys. Plasmas 2 (1995) 2176]. Trace impurity

275

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

276

Technical assessment of critical Plasma-Materials Interaction (PMI) and High Heat Flux (HHF) issues for alternative fusion concepts (AFCs)  

SciTech Connect

A number of approaches to fusion energy are being pursued as alternative fusion concepts (AFCs). The goal of these systems is to provide a more desirable method of producing fusion energy than the mainline programs. Some of the AFCs have both a Low Power Density (LPD) option and a High Power Density (HPD) option. A summary of representative AFC programs and their associated PMI and HHF issues is followed by the technical assessment of the critical issues. These requirements are discussed relative to the mainline and/or HPD components. The HPD options are contrasted with a tabulation of the characteristics of components for the Reversed-Field Pinch (RFP), which is representative of the HPD concept.

Downing, J.N.

1986-03-01

277

Inertial confinement fusion: steady progress towards ignition and high gain (summary talk)  

Microsoft Academic Search

Based on the results presented at the 20th IAEA Fusion Energy Conference 2004, this paper highlights the most important recent advances in inertial confinement fusion (ICF). With the construction of the National Ignition Facility (NIF) and the Laser Mgajoule facility and many improvements in the target design, the conventional indirect-drive approach is advancing steadily towards the demonstration of ignition and

M. M. Basko

2005-01-01

278

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

279

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

280

The effects of beta-alanine supplementation and high-intensity interval training on neuromuscular fatigue and muscle function  

Microsoft Academic Search

The purpose of this study was to determine the effects of beta-alanine supplementation and high-intensity interval training\\u000a (HIIT) on electromyographic fatigue threshold (EMGFT) and efficiency of electrical activity (EEA). A total of 46 men completed four, 2-min work bouts on a cycle ergometer. Using\\u000a bipolar surface electrodes, the EMG amplitude was averaged and plotted over the 2-min. The resulting slopes

Abbie E. Smith; Jordan R. Moon; Kristina L. Kendall; Jennifer L. Graef; Christopher M. Lockwood; Ashley A. Walter; Travis W. Beck; Joel T. Cramer; Jeffrey R. Stout

2009-01-01

281

Blood pressure and plasma noradrenaline during single high-dose beta adrenoceptor blockade  

Microsoft Academic Search

The acute effects upon blood pressure and sympathetic outflow of two beta adrenoceptor blocking drugs, propranolol and atenolol, are described in five healthy normotensive subjects. Supine blood pressure, heart rate, plasma noradrenaline, and urinary catecholamine excretion were measured before and at intervals for 24 h after a single oral dose of either propranolol 200 mg, atenolol 100 mg, or placebo.

T. J. B. Maling; A. Ferrara; J. C. Mucklow; J. L. Reid; Carlene A. Hamilton; C. T. Dollery

1979-01-01

282

High-Precision Measurements of the Superallowed Beta+ Decays of 38Ca and 46V  

E-print Network

As a part of our program to test the unitarity of the Cabibbo-Kobayashi-Maskawa matrix, the decay of the superallowed 0? --> 0? beta emitters ?Ca and ??V has been studied in this dissertation. For ?Ca, the half-life, 443.88(36) ms...

Park, Hyo-In

2012-10-19

283

Testing the Validity of an Antineutrino Anomaly with High Precision Beta Spectra  

NASA Astrophysics Data System (ADS)

In January 2011 Mueller, T.A., et al. published a new method for predicting the antineutrino spectra which is derived from a complex fit to the fission beta spectra. They take into account many more beta spectra and nuclear effects than what was originally performed independently in the early 1980s by Vogel, P. and Schreckenbach, K. As a result of the improved prediction, Mueller and colleagues then published a re-analysis of the reactor fission beta spectra and the resultant antineutrino spectrum. They found that there is an uncertainty in the flux normalization of about 3% from the early calculations and their much more elaborate approach. This has been dubbed the ``antineutrino anomaly.'' The current work is aimed to independently cross-check the methods, assumptions, and underlying beta theory in which the new calculation from Mueller, et al. heavily rely. The normalization uncertainty in the flux could be interpreted as a large mass splitting sterile neutrino and opens the venue for a profound amount of new physics, as well as casts doubt onto many years of previous work. As such, it is very important that we have a precise and independent cross-check of the elaborate method. I will present an overview of the problem and the status of the current work.

Keefer, Gregory; Classen, Timothy

2012-03-01

284

High-{beta} island-divertor equilibria of a quasi-isodynamic stellarator  

SciTech Connect

A stellarator vacuum field is found for which free-boundary MHD quasi-isodynamic equilibria with a nearly invariant island structure in the vacuum field region surrounding the plasma are obtained for Left-Pointing-Angle-Bracket {beta} Right-Pointing-Angle-Bracket values up to about 0.07.

Mikhailov, M. I., E-mail: mikhail@nfi.kiae.ru [National Research Centre Kurchatov Institute (Russian Federation); Drevlak, M.; Nuehrenberg, J., E-mail: juergen.nuehrenberg@ipp.mpg.de [EURATOM Assoziation, Teilinstitut Greifswald, Max-Planck-Institut fuer Plasmaphysik (Germany)

2013-07-15

285

The beta3 integrin gene is expressed at high levels in the major haematopoietic and lymphoid organs, vascular system, and skeleton during mouse embryo development.  

PubMed

Integrins are a family of cell surface molecules that mediate the attachment of cells to the extracellular matrix (ECM). These alphabeta heterodimers are involved in many biological processes. We used northern blotting and in situ hybridization to study the pattern of beta3 integrin gene expression during mouse embryogenesis. Northern blotting detected two species of beta3 mRNA from 7 to 17 days post coitum (dpc). These transcripts were abundant in the adult testis, kidney, liver, spleen, and heart. In situ hybridization experiments detected high levels of beta3 in the major haematopoietic and lymphoid organs: yolk sac, liver, and thymus. Moreover, beta3 transcripts were also detected in the vascular system, where beta3 integrin probably plays a key role in angiogenesis and vasculogenesis. We also detected a hybridization signal in the gut, the bronchioles of the lungs, and the bladder wall. beta3 transcripts were also present in the medullary regions of the adrenal glands and in the developing skeleton. Our study shows that beta3 gene expression is not restricted to the liver and gut during mouse development. We also detected beta3 integrin mRNA in the yolk sac, vessels, lung, bladder, and developing bones. Our data suggest that beta3 integrin plays a key role in many important physiological processes like haematopoiesis, angiogenesis, phagocytosis, and bone resorption. PMID:14668060

Le Gat, Laurence; Gogat, Karn; Van Den Berghe, Loc; Brizard, Mara; Kobetz, Alexandra; Marchant, Dominique; Abitbol, Marc; Mnasche, Maurice

2003-01-01

286

Ion fusion of high-resolution LC-MS-based metabolomics data to discover more reliable biomarkers.  

PubMed

A systematic approach for the fusion of associated ions from a common molecule was developed to generate "one feature for one peak" metabolomics data. This approach guarantees that each molecule is equally selected as a potential biomarker and may largely enhance the chance to obtain reliable findings without employing redundant ion information. The ion fusion is based on low mass variation in contrast to the theoretical calculation measured by a high-resolution mass spectrometer, such as LTQ orbitrap, and a high correlation of ion pairs from the same molecule. The mass characteristics of isotopic distribution, neutral loss, and adduct ions were simultaneously applied to inspect each extracted ion in the range of a predefined retention time window. The correlation coefficient was computed with the corresponding intensities of each ion pair among all experimental samples. Serum metabolomics data for the investigation of hepatocellular carcinoma (HCC) and healthy controls were utilized as an example to demonstrate this strategy. In total, 609 and 1084 ion pairs were respectively found meeting one or more criteria for fusion, and therefore fused to 106 and 169 metabolite features of the datasets in the positive and negative modes, respectively. The important metabolite features were separately discovered and compared to distinguish the HCC from the healthy controls using the two datasets with and without ion fusion. The results show that the developed method can be an effective tool to process high-resolution mass spectrometry data in "omics" studies. PMID:24611595

Zeng, Zhongda; Liu, Xinyu; Dai, Weidong; Yin, Peiyuan; Zhou, Lina; Huang, Qiang; Lin, Xiaohui; Xu, Guowang

2014-04-15

287

Characterization of a Highly Conserved Domain within the Severe Acute Respiratory Syndrome Coronavirus Spike Protein S2 Domain with Characteristics of a Viral Fusion Peptide?  

PubMed Central

Many viral fusion proteins are primed by proteolytic cleavage near their fusion peptides. While the coronavirus (CoV) spike (S) protein is known to be cleaved at the S1/S2 boundary, this cleavage site is not closely linked to a fusion peptide. However, a second cleavage site has been identified in the severe acute respiratory syndrome CoV (SARS-CoV) S2 domain (R797). Here, we investigated whether this internal cleavage of S2 exposes a viral fusion peptide. We show that the residues immediately C-terminal to the SARS-CoV S2 cleavage site SFIEDLLFNKVTLADAGF are very highly conserved across all CoVs. Mutagenesis studies of these residues in SARS-CoV S, followed by cell-cell fusion and pseudotyped virion infectivity assays, showed a critical role for residues L803, L804, and F805 in membrane fusion. Mutation of the most N-terminal residue (S798) had little or no effect on membrane fusion. Biochemical analyses of synthetic peptides corresponding to the proposed S2 fusion peptide also showed an important role for this region in membrane fusion and indicated the presence of ?-helical structure. We propose that proteolytic cleavage within S2 exposes a novel internal fusion peptide for SARS-CoV S, which may be conserved across the Coronaviridae. PMID:19439480

Madu, Ikenna G.; Roth, Shoshannah L.; Belouzard, Sandrine; Whittaker, Gary R.

2009-01-01

288

Controlled nuclear fusion apparatus  

Microsoft Academic Search

A fusion power generating device is disclosed having a relatively small and inexpensive core region which may be contained within an energy absorbing blanket region. The fusion power core region contains apparatus of the toroidal type for confining a high density plasma. The fusion power core is removable from the blanket region and may be disposed and\\/or recycled for subsequent

R. W. Bussard; B. Coppi

1982-01-01

289

Spatially resolved high resolution x-ray spectroscopy for magnetically confined fusion plasmas (invited)  

SciTech Connect

The use of high resolution x-ray crystal spectrometers to diagnose fusion plasmas has been limited by the poor spatial localization associated with chord integrated measurements. Taking advantage of a new x-ray imaging spectrometer concept [M. Bitter et al., Rev. Sci. Instrum. 75, 3660 (2004)], and improvements in x-ray detector technology [Ch. Broennimann et al., J. Synchrotron Radiat. 13, 120 (2006)], a spatially resolving high resolution x-ray spectrometer has been built and installed on the Alcator C-Mod tokamak. This instrument utilizes a spherically bent quartz crystal and a set of two dimensional x-ray detectors arranged in the Johann configuration [H. H. Johann, Z. Phys. 69, 185 (1931)] to image the entire plasma cross section with a spatial resolution of about 1 cm. The spectrometer was designed to measure line emission from H-like and He-like argon in the wavelength range 3.7 and 4.0 A with a resolving power of approximately 10 000 at frame rates up to 200 Hz. Using spectral tomographic techniques [I. Condrea, Phys. Plasmas 11, 2427 (2004)] the line integrated spectra can be inverted to infer profiles of impurity emissivity, velocity, and temperature. From these quantities it is then possible to calculate impurity density and electron temperature profiles. An overview of the instrument, analysis techniques, and example profiles are presented.

Ince-Cushman, A.; Rice, J. E.; Reinke, M. L.; Podpaly, Y.; Marmar, E. S. [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Bitter, M.; Hill, K. W.; Scott, S. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Gu, M. F. [Lawrence Livermore National Laboratory, California 94550 (United States); Eikenberry, E.; Broennimann, Ch. [DECTRIS Ltd., Villigen-PSI 5232 (Switzerland); Lee, S. G. [National Fusion Research Institute, Yusung, Taejeon 305-333 (Korea, Republic of)

2008-10-15

290

Energy transfer from fusion alpha particles to externally driven high frequency waves in a tokamak  

NASA Astrophysics Data System (ADS)

The possibility of energy transfer from fusion alpha particles to externally driven wave fields for the purpose of driving current in a tokamak reactor was originally suggested by Fisch and Rax (Phys. Rev. Lett. 69 (1992) 612). The idea is reconsidered here for a class of alpha particle distribution functions that is nearly isotropic, except for the presence of diamagnetic flow due to radial inhomogeneity. The transfer of energy from alpha particles to high frequency waves (far above the ion gyrofrequency) requires that the driving term, which is proportional to the radial gradient of the alpha particle distribution function, be large enough to dominate the usual Landau damping. For a classic slowing down distribution, Landau damping dominates and the alpha particles absorb energy from the waves. Alternatively, if the alpha particle distribution is peaked near the birth speed, then the radial gradient driving term tends to dominate and energy can be extracted by the waves. Radial diffusion is a natural mechanism which displaces alpha particles outward before they can slow down (locally). However, a solution of a model Fokker-Planck equation, including radial diffusion and collisional slowing down, shows that the alpha particle distribution function still tends to absorb energy from the waves. Within the context of linear theory, high frequency waves may not be optimal as a means of extracting energy from alpha particles

Kupfer, K.; Chiu, S. C.; Chan, V. S.

1995-02-01

291

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

292

Particle-in-Cell Simulations of the High Frequency Hybrid Instability in Inertial Confiment Fusion Plasmas  

NASA Astrophysics Data System (ADS)

We present results on the laser-plasma interaction near the quarter critical surface under conditions relevant to inertial fusion. Under these conditions, the high frequency hybrid instability (HFHI) where one of the daughter waves have mixed polarization, is likely to be dominant. In fully nonlinear kinetic simulations with the code OSIRIS we show that the spectrum at early time is consistent with theory and the growth rate predicted by HFHI theory is born out by these simulations. We also investigate the saturated electrostatic (and electromagnetic) spectrum for long timescales for both fixed and mobile ions. For high temperatures where the HFHI is dominant the absorption is dominated by the absolutely unstable modes and absorption levels near 40% can occur even below the pure 2wp modes. In these cases, it is possible to excite HFHI modes as long as one is above the Raman threshold. We also investigate in detail the evolution of unstable modes. Nonlinear effects, such as the generation of hot electrons, half harmonics and the excitation of low frequency ion fluctuations, will also be discussed.

Tsung, Frank; Afeyan, B. B.; Mori, W. B.

2010-11-01

293

Experimental investigation of opacity models for stellar interior, inertial fusion, and high energy density plasmas  

SciTech Connect

Theoretical opacities are required for calculating energy transport in plasmas. In particular, understanding stellar interiors, inertial fusion, and Z pinches depends on the opacities of mid-atomic-number elements over a wide range of temperatures. The 150-300 eV temperature range is particularly interesting. The opacity models are complex and experimental validation is crucial. For example, solar models presently disagree with helioseismology and one possible explanation is inadequate theoretical opacities. Testing these opacities requires well-characterized plasmas at temperatures high enough to produce the ion charge states that exist in the sun. Typical opacity experiments heat a sample using x rays and measure the spectrally resolved transmission with a backlight. The difficulty grows as the temperature increases because the heating x-ray source must supply more energy and the backlight must be bright enough to overwhelm the plasma self-emission. These problems can be overcome with the new generation of high energy density (HED) facilities. For example, recent experiments at Sandia's Z facility [M. K. Matzen et al., Phys. Plasmas 12, 055503 (2005)] measured the transmission of a mixed Mg and Fe plasma heated to 156{+-}6 eV. This capability will also advance opacity science for other HED plasmas. This tutorial reviews experimental methods for testing opacity models, including experiment design, transmission measurement methods, accuracy evaluation, and plasma diagnostics. The solar interior serves as a focal problem and Z facility experiments illustrate the techniques.

Bailey, J. E.; Rochau, G. A. [Sandia National Laboratories, Albuquerque, New Mexico, 87185-1196 (United States); Mancini, R. C. [University of Nevada, Reno, Nevada 89557 (United States); Iglesias, C. A. [Lawrence Livermore National Laboratory, University of California, Livermore, California 94550 (United States); MacFarlane, J. J.; Golovkin, I. E. [Prism Computational Sciences, Madison, Wisconsin 53703 (United States); Blancard, C.; Cosse, Ph.; Faussurier, G. [CEA, DAM, DIF, F-91297 Arpajon (France)

2009-05-15

294

Effect of pressure-driven MHD instabilities on confinement in reactor-relevant high-beta helical plasmas  

SciTech Connect

Through the experiment data analysis in the large helical device (LHD), the influence of the global MHD instability and the relatively short wave length MHD instabilities driven turbulence on the confinement performance in reactor-relevant high-beta helical plasmas is studied. The comparison of the energy confinement time between just before global MHD instability disappears and after that, and the estimation of the saturated mode structure by the multi-channel soft x-ray measurement enable us to quantitatively estimate the influence of the global interchange type MHD instability with different saturated mode structures on the confinement performance. According to the comparison between thermal conductivities in experiments and those predicted by theoretical transport models, the transport properties in the peripheral region of high beta LHD plasmas are quite similar with anomalous transport model based on an interchange type MHD instability driven turbulence, and that result is supported by the dependence of the density fluctuation with relatively short wave length on beta value.

Watanabe, K. Y.; Takemura, Y.; Funaba, H.; Sakakibara, S.; Tanaka, K.; Ohdachi, S.; Toi, K.; Narushima, Y. [National Institute for Fusion Science, Toki 509-5292 (Japan); Masamune, S. [Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan); Watanabe, F. [Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan)

2011-05-15

295

Finding an Emission Line Signature in the H-alpha/H-beta Plane for High Mass X-ray Binaries  

NASA Astrophysics Data System (ADS)

Using a new spectrophotometrically developed system we have examined the relative strengths of the H-alpha and H-beta lines in a sample of 18 High Mass X-ray Binaries (HMXB) and 1 Low Mass X-ray Binary (LMXB). This sample defines a very distinct path in the H-alpha/H-beta plot. This signature can be used to identify potential optical counterparts to x-ray sources that might be HMXB systems. We will present our results for this initial sample based on spectral observations taken at the Dominion Astrophysical Observatory 1.2-m Telescope. In addition, we will present long term monitoring of a number of systems. Finally, we will present a sample of photometric observations from the BYU West Mountain 0.9-m. The photometric observations were used to confirm the identification of known HMXB systems. This work is partially supported by NSF Grant AST-0618209.

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

2013-01-01

296

PPPL-3224, Preprint: February 1997, UC-420, 426 Plasma Transport Control and Self-Sustaining Fusion Reactor*  

E-print Network

PPPL-3224, Preprint: February 1997, UC-420, 426 Plasma Transport Control and Self-Sustaining Fusion- isfy 1. high beta, 2. high bootstrap fraction (self-sustaining), and 3. high confinement is discussed. In CDX-U, a tokamak configuration was created and sustained solely by internally generated bootstrap

297

Association for Women in Beta Beta Beta  

E-print Network

(Honor Society) MusicSymphonic BandUniversity SymphonyOrchestraWomen's ChorusMen's ChorusConcert ChoraleBiology Association for Women in Science (A.W.I.S.) Beta Beta Beta (National Honor Society) Sigma(Conversation Table)Sigma Delta Pi(National Honor Society) Theatre and FilmUT Film and VideoSocietyAlpha Psi Omega

Viola, Ronald

298

Compact reversed-field pinch reactor (CRFPR): a high-density approach to magnetic fusion energy  

SciTech Connect

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 are comparable to fission power plants and are an order of magnitude more favorable than the conventional fusion approaches. A comprehensive system model predicts the CRFPR point design to be surprisingly resilient to changes in key, but relatively unknown, physics and systems parameters.

Hagenson, R.L.; Krakowski, R.A.; Byrne, R.N.; Dobrott, D.

1982-01-01

299

A Novel Chimeric Protein-based HIV-1 Fusion Inhibitor Targeting gp41 Glycoprotein with High Potency and Stability*  

PubMed Central

T20 (enfuvirtide, Fuzeon) is the first generation HIV-1 fusion inhibitor approved for salvage therapy of HIV-1-infected patients refractory to current antiretroviral drugs. However, its application is limited by the high cost of peptide synthesis, rapid proteolysis, and poor efficacy against emerging drug-resistant strains. Here we reported the design of a novel chimera protein-based fusion inhibitor targeting gp41, TLT35, that uses a flexible 35-mer linker to couple T20 and T1144, the first and next generation HIV-1 fusion inhibitors, respectively. TLT35, which was expressed in Escherichia coli with good yield, showed low nm activity against HIV-1-mediated cell-cell fusion and infection by laboratory-adapted HIV-1 strains (X4 or R5), including T20-resistant variants and primary HIV-1 isolates of clades A to G and group O (R5 or X4R5). TLT35 was stable in human sera and in peripheral blood mononuclear cell culture and was more resistant to proteolysis than either T20 or T1144 alone. Circular dichroism spectra showed that TLT35 folded into a thermally stable conformation with high ?-helical content and Tm value in aqueous solution. It formed a highly stable complex with gp41 N-terminal heptad repeat peptide and blocked formation of the gp41 six-helix-bundle core. These merits combined with an anticipated low production cost for expression of TLT35 in E. coli make this novel protein-based fusion inhibitor a promising candidate for further development as an anti-HIV-1 microbicide or therapeutic for the prevention and treatment of HIV-1 infection. PMID:21690094

Pan, Chungen; Cai, Lifeng; Lu, Hong; Lu, Lu; Jiang, Shibo

2011-01-01

300

High efficiency beta radioisotope energy conversion using reciprocating electromechanical converters with integrated betavoltaics  

Microsoft Academic Search

We demonstrate a 5.1% energy conversion efficiency 63Ni radioisotope power generator by integrating silicon betavoltaic converters with radioisotope actuated reciprocating piezoelectric unimorph cantilever converters. The electromechanical energy converter efficiently utilizes both the kinetic energy and the electrical charge of the 0.94 muW beta radiation from a 9 mCi 63Ni thin film source to generate maximum (1) continuous betavoltaic electrical power

Rajesh Duggirala; Hui Li; Amit Lal

2008-01-01

301

Virtual Screening against Highly Charged Active Sites: Identifying Substrates of Alpha?Beta Barrel Enzymes  

Microsoft Academic Search

We have developed a virtual ligand screening method designed to help assign enzymatic function for alpha-beta barrel proteins. We dock a library of 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-

Chakrapani Kalyanaraman; Katarzyna Bernacki; Matthew P. Jacobson

2005-01-01

302

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 reactors 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

303

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

304

Progress towards a high-gain and robust target design for heavy ion fusion  

NASA Astrophysics Data System (ADS)

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 50 g/cm3 at peak compression, and fusion gains of 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 2 g/cm2 using two annular beams to implode the target to peak DT densities 100 g/cm3, followed by a fast-ignition solid ion beam which heats the high-density fuel to thermonuclear temperatures in 200 ps to start the burn propagation, obtaining gains of 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 ?R) located at the vertex of the X-target.

Henestroza, Enrique; Grant Logan, B.

2012-07-01

305

Recent advances in high current vacuum arc ion sources for heavy ion fusion  

NASA Astrophysics Data System (ADS)

For a heavy ion fusion induction linac driver, a source of heavy ions with charge states 1+-3+, ?0.5 A current beams, ?20 ?s pulse widths and 10 Hz 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) ionization potential elements and offer relatively low ion fluxes with a charge state limited to 1+. Gas injection sources suffer from partial ionization and deleterious neutral gas effects. The above shortcomings of the thermionic ion sources can be overcome by a vacuum arc ion source. The vacuum arc ion source is a good candidate for HIF applications. It is capable of providing ions of various elements and different charge states in short and long pulse bursts and high beam current density. Under a Phase-I STTR from DOE, the feasibility of the vacuum arc ion source for the HIF applications was investigated. We have modified an existing vacuum arc ion source at LBNL to produce a gadolinium ( A?158) ion beam with >0.5 A beam current, 120 keV beam energy, ?6 cm diameter extraction aperture and ?20 ?s pulse width. The average beam current density at the extraction grids was ?17 mA/cm 2. We have measured that >85% Gd ions were in the 3+ charge state, the beam current fluctuation level (rms) was ?3%, pulse-to-pulse variation of the beam (rms) was about 3%, the uniformity of the beam density over its 6 cm diameter was ?98% and the ion longitudinal energy spread was ?1%. Additional measurements were made to improve charge state purity by using other materials and employing an axial magnetic field close to the cathode. Yttrium ( A?89), lead ( A?207), and Ba ( A?137) were tested at similar current parameters with Ba delivering nearly a pure charge state with >95% being in 2+ state. The results of the experiments indicate that the vacuum arc ion source is a good candidate for HIF applications.

Qi, Niansheng; Schein, Jochen; Prasad, Rahul R.; Krishnan, Mahadevan; Anders, Andre; Kwan, Joe; Brown, Ian

2001-05-01

306

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

307

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 ?2040 ?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 12-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. PMID:18689464

Venegas, Berenice; Wolfson, Marla R.; Cooke, Peter H.; Chong, Parkson Lee-Gau

2008-01-01

308

We report the first production of high beta plasma confined in a fully levitated laboratory dipole using neutral gas fueling and electron  

E-print Network

transport Low density Low diamagnetism (low ) High Beta Regime: Large diamagnetic current Measurable Afterglow: (no input power) Low density Slow diamagnetism decay Quiescent with instability bursts 0.0 2

309

High shear mixing granulation of ibuprofen and beta-cyclodextrin: effects of process variables on ibuprofen dissolution.  

PubMed

The aims of the study were to evaluate the effect of high shear mixer (HSM) granulation process parameters and scale-up on wet mass consistency and granulation characteristics. A mixer torque rheometer (MTR) was employed to evaluate the granulating solvents used (water, isopropanol, and 1:1 vol/vol mixture of both) based on the wet mass consistency. Gral 25 and mini-HSM were used for the granulation. The MTR study showed that the water significantly enhanced the beta-cyclodextrin (beta CD) binding tendency and the strength of liquid bridges formed between the particles, whereas the isopropanol/water mixture yielded more suitable agglomerates. Mini-HSM granulation with the isopropanol/water mixture (1:1 vol/vol) showed a reduction in the extent of torque value rise by increasing the impeller speed as a result of more breakdown of agglomerates than coalescence. In contrast, increasing the impeller speed of the Gral 25 resulted in higher torque readings, larger granule size, and consequently, slower dissolution. This was due to a remarkable rise in temperature during Gral granulation that reduced the isopropanol/water ratio in the granulating solvent as a result of evaporation and consequently increased the beta CD binding strength. In general, the HSM granulation retarded ibuprofen dissolution compared with the physical mixture because of densification and agglomeration. However, a successful HSM granulation scale-up was not achieved due to the difference in the solvent mixture's effect from 1 scale to the other. PMID:18181545

Ghorab, Mohamed K; Adeyeye, Moji Christianah

2007-01-01

310

High-precision {beta} decay half-life measurements of proton-rich nuclei for testing the CVC hypothesis  

SciTech Connect

The experimental study of super-allowed nuclear {beta} decays serves as a sensitive probe of the conservation of the weak vector current (CVC) and allows tight limits to be set on the presence of scalar or right-handed currents. Once CVC is verified, it is possible to determine the V{sub ud} element of the CKM quark-mixing matrix. Similarly, the study of nuclear mirror {beta} decays allows to arrive at the same final quantity V{sub ud}. Whereas dedicated studies of 0{sup +}{yields}0{sup +} decays are performed for several decades now, the potential of mirror transitions was only rediscovered recently. Therefore, it can be expected that important progress is possible with high-precision studies of different mirror {beta} decays. In the present piece of work the half-life measurements performed by the CENBG group of the proton-rich nuclei {sup 42}Ti, {sup 38-39}Ca, {sup 30-31}S and {sup 29}P are summarised.

Kurtukian-Nieto, T. [Centre d'Etudes Nucleaires de Bordeaux-Gradignan (CENBG), Universite Bordeaux 1, CNRS/IN2P3, Chemin du Solarium, BP 120, F-33175 Gradignan cedex (France); Collaboration: NEX Group of CENBG

2011-11-30

311

A National Collaboratory to Advance the Science of High Temperature Plasma Physics for Magnetic Fusion  

SciTech Connect

This report summarizes the work of the National Fusion Collaboratory (NFC) Project to develop a persistent infrastructure to enable scientific collaboration for magnetic fusion research. The original objective of the NFC project was to develop and deploy a national FES ??Grid (FusionGrid) that would be a system for secure sharing of computation, visualization, and data resources over the Internet. The goal of FusionGrid was to allow scientists at remote sites to participate as fully in experiments and computational activities as if they were working on site thereby creating a unified virtual organization of the geographically dispersed U.S. fusion community. The vision for FusionGrid was that experimental and simulation data, computer codes, analysis routines, visualization tools, and remote collaboration tools are to be thought of as network services. In this model, an application service provider (ASP provides and maintains software resources as well as the necessary hardware resources. The project would create a robust, user-friendly collaborative software environment and make it available to the US FES community. This Grid'??s resources would be protected by a shared security infrastructure including strong authentication to identify users and authorization to allow stakeholders to control their own resources. In this environment, access to services is stressed rather than data or software portability.

Schissel, David P. [Princeton Plasma Physics Lab., NJ (United States); Abla, G. [Princeton Plasma Physics Lab., NJ (United States); Burruss, J. R. [Princeton Plasma Physics Lab., NJ (United States); Feibush, E. [Princeton Plasma Physics Lab., NJ (United States); Fredian, T. W. [Massachusetts Institute of Technology, Cambridge, MA (United States); Goode, M. M. [Lawrence Berkeley National Lab., CA (United States); Greenwald, M. J. [Massachusetts Institute of Technology, Cambridge, MA (United States); Keahey, K. [Argonne National Lab., IL (United States); Leggett, T. [Argonne National Lab., IL (United States); Li, K. [Princeton Univ., NJ (United States); McCune, D. C. [Princeton Plasma Physics Lab., NJ (United States); Papka, M. E. [Argonne National Lab., IL (United States); Randerson, L. [Princeton Plasma Physics Lab., NJ (United States); Sanderson, A. [Univ. of Utah, Salt Lake City, UT (United States); Stillerman, J. [Massachusetts Institute of Technology, Cambridge, MA (United States); Thompson, M. R. [Lawrence Berkeley National Lab., CA (United States); Uram, T. [Argonne National Lab., IL (United States); Wallace, G. [Princeton Univ., NJ (United States)

2012-12-20

312

Fusion-Fission Hybrids Driven By Heavy Ion Inertial Fusion  

Microsoft Academic Search

There is a desire to resolve fuel cycle issues for increasing the role of nuclear energy. The recent Laser Inertial Fusion-Fission Energy (LIFE) initiative that builds upon NIF ignition, is likely to rekindle national interest in developing intense, high power ion beam accelerators for fusion energy production and for fusion-fission hybrid concepts that combine an ion beam driven fusion neutron

P. A. Seidl

313

Analysis of three plasmid systems for use in DNA A beta 42 immunization as therapy for Alzheimer's disease.  

PubMed

In an effort to optimize DNA immunization-elicited antibody production responses against A beta 1-42 (A beta 42) as a therapy for Alzheimer's disease (AD), comparisons were made between three distinct plasmid systems using gene gun delivery. Plasmids encoding A beta 42 monomer and a novel A beta 42 trimeric fusion protein were evaluated in conjunction with CMV or Gal4/UAS promoter elements. It was found that vaccination A beta 42 trimer under the Gal4/UAS promoter elicited high levels of anti-A beta 42 antibody production. Serum antibody levels from Gal4/UAS-A beta 42 trimer immunized mice were found to be 16.6+/-5.5 microg/ml compared to 6.5+/-2.5 microg/ml with Gal4/UAS-A beta 42 monomer or even less with CMV-A beta 42 trimer. As compared to monomeric A beta 42 or A beta 42 trimer expressed under the CMV promoter, injection of the Gal4/UAS-A beta 42 trimer induced high levels of A beta 42 antigen expression in tissue suggesting a mechanism for the increase in anti-A beta 42 antibody. Antibodies were found to be primarily IgG1 suggesting a predominant Th2 response (IgG1/IgG2a ratio of 9). Serum from A beta 42 trimer-vaccinated mice was also found to identify amyloid plaques in the brains of APP/PS1 transgenic mice. These results demonstrate the potential therapeutic use of Gal4/UAS DNA A beta 42 trimer immunization in preventing Alzheimer's disease. PMID:20562015

Qu, Bao-Xi; Lambracht-Washington, Doris; Fu, Min; Eagar, Todd N; Stve, Olaf; Rosenberg, Roger N

2010-07-19

314

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 ILEOsaka. 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

315

Highly stable beta-class carbonic anhydrases useful in carbon capture systems  

DOEpatents

The present disclosure relates to .beta.-class carbonic anhydrase polypeptides having improved properties including increased thermostability and/or stability in the presence of amine compounds, ammonia, or carbonate ion. The present disclosure also provides formulations and uses of the polypeptides for accelerating the absorption of carbon dioxide from a gas stream into a solution as well as for the release of the absorbed carbon dioxide for further treatment and/or sequestering. Also provided are polynucleotides encoding the carbonic anhydrase polypeptides and host cells capable of expressing them.

Alvizo, Oscar; Benoit, Mike; Novick, Scott

2013-04-16

316

Highly Potent, Water Soluble Benzimidazole Antagonist for Activated (alpha)4(beta)1 Integrin  

SciTech Connect

The cell surface receptor {alpha}{sub 4}{beta}{sub 1} integrin, activated constitutively in lymphoma, can be targeted with the bisaryl urea peptidomimetic antagonist 1 (LLP2A). However, concerns on its preliminary pharmacokinetic (PK) profile provided an impetus to change the pharmacophore from a bisaryl urea to a 2-arylaminobenzimidazole moiety resulting in improved solubility while maintaining picomolar potency [5 (KLCA4); IC{sub 50} = 305 pM]. With exceptional solubility, this finding has potential for improving PK to help diagnose and treat lymphomas.

Carpenter, R D; Andrei, M; Lau, E Y; Lightstone, F C; Liu, R; Lam, K S; Kurth, M J

2007-08-29

317

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

Microsoft Academic Search

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

M. E. Cuneo; R. A. Vesey; D. B. Sinars; E. M. Waisman; R. W. Lemke; D. E. Bliss; W. A. Stygar; J. L. Porter; M. G. Mazarakis; G. A. Chandler; T. A. Mehlhorn; J. P. Chittenden; S. V. Lebedev; D. G. Schroen

2005-01-01

318

Thermoluminescence dosimetric properties of a new thin beta detector (LiF:Mg, Cu, P; GR-200F) in comparison with highly sensitive Al2O3:C beta dosimeters.  

PubMed

There is an increasing need for efficient beta detectors to fulfil ICRU recommendations for new quantities especially in the field of medical physics and retrospective dosimetry. The thermoluminescence properties of thin LiF:Mg, Cu, P (GR-200F) tapes produced in 1998 by Sange Company, People's Republic of China, are investigated and compared with those of highly sensitive thin Al2O3:C beta detectors as regards their applicability in the detection of low energy photons and beta particles. The radiation dose response, minimum detectable dose, reproducibility of measurements and effect of residual signal at low dose are assessed for the possible low level beta dosimetry use. The radiation dose response and photon and beta detection efficiencies are tested underpractical laboratory conditions. The effects of indoor fluorescent light and residual signal after the first read-out are investigated with a view to optimising handling conditions such as post-irradiation and pre-heating treatments for routine dosimetry. The photon energy responses of the detectors are investigated using 150 keV filtered x-rays and 60Co gamma-rays. PMID:15511019

El-Faramawy, N A; Gksu, H Y; Panzer, W

2004-09-01

319

The National Spherical Torus Experiment (NSTX) research programme 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 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 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} {triple_bond}

/(B{sub T0}{sup 2}/2{mu}{sub 0}) of up to 35%. Normalized beta values often exceed the no-wall limit, and studies suggest that passive wall mode stabilization enables this for H mode plasmas with broad pressure profiles. 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. HHFW effectively heats electrons, and its acceleration of fast beam ions has been observed. Evidence for HHFW current drive is obtained by comparison of the loop voltage evolution in plasmas with matched density and temperature profiles but varying phases of launched HHFW waves. Studies of emissions from electron Bernstein waves indicate a density scale length dependence of their transmission across the upper hybrid resonance near the plasma edge that is consistent with theoretical predictions. A peak heat flux to the divertor targets of 10 MW m{sup -2} has been measured in the H mode, with large asymmetries being observed in the power deposition between the inner and outer strike points. Non-inductive plasma startup studies have focused on coaxial helicity injection. With this technique, toroidal currents up to 400 kA have been driven, and studies to assess flux closure and coupling to other current drive techniques have begun.

Johnson, D.W. (Princeton University, Princeton, NJ); Grisham, L.R. (Princeton University, Princeton, NJ); Zweben, S. J. (Princeton University, Princeton, NJ); Gates, D.A. (Princeton University, Princeton, NJ); Bush, C. (Oak Ridge National Laboratory, Oak Ridge, TN); Synakowski, E.J. (Princeton University, Princeton, NJ); Hosea, J. C. (Princeton University, Princeton, NJ); Blanchard, W. (Princeton University, Princeton, NJ); Bell, Michael G. (Princeton University, Princeton, NJ); Sabbagh, S. (Columbia University, New York, NY); Soukhanovskii, V. (Princeton University, Princeton, NJ); Raman, R. (University of Washington, Seattle, WA,); Peng, Y-K. M. (Oak Ridge National Laboratory, Oak Ridge, TN); Ono, M. (Princeton University, Princeton, NJ); Stevenson, T. (Princeton University, Princeton, NJ); Fredrickson, E. D. (Princeton University, Princeton, NJ); Kubota, Shigeru (University of California, Los Angeles, CA); Efthimion, P. C. (Princeton University, Princeton, NJ); Bourdelle, C. (CEA Cadarache, France); Wilson, J.R. (Princeton University, Princeton, NJ); Maqueda, R. (Los Alamos National Laboratory, Los Alamos, NM); Kaye, S. M. (Princeton University, Princeton, NJ); Kaita, R. (Princeton University, Princeton, NJ); Maingi, R. (Oak Ridge National Laboratory, Oak Ridge, TN); Darrow, D. S. (Princeton University, Princeton, NJ); Bitter, M. (Princeton University, Princeton, NJ); Kugel, Henry W. (Princeton University, Princeton, NJ); Skinner, C. H. (Princeton University, Princeton, NJ); Wilgen, J. (Oak Ridge National Laboratory, Oak Ridge, TN); Von Halle, A. (Princeton University, Princeton, NJ); Taylor, G. (Princeton University, Princeton, NJ); Mueller, D. (Princeton University, Princeton, NJ); Swain, D. W. (Oak Ridge National Laboratory, Oak Ridge, TN); Ryan, P.M. (Oak Ridge National Laboratory, Oak Ridge, TN); Rosenberg, A. (Princeton University, Princeton, NJ); Ramakrishnan, S. (Princeton University, Princeton, NJ); Phillips, C.K. (Princeton University, Princeton, NJ); Paul, S. (Princeton University, Princeton, NJ); Park, H.K. (Princeton University, Princeton, NJ); Paoletti, F. (Columbia University, New York, NY); Boedo, J. (University of California, San Diego, CA); Williams, M. (Princeton University, Princeton, NJ); Gilmore, Mark A. (University of New Mexico, Albuquerque, NM); LeBlanc, B. (Princeton University, Princeton, NJ); Bigelow, T. (Oak Ridge National Laboratory, Oak Ridge, TN); Bell, R. E. (Princeton University, Princeton, NJ); Roquemore, A. L. (Princeton University, Princeton, NJ); Wampler, William R.; Medley, S. S. (Princeton University, Princeton, NJ); Stutman, D. (Johns Hopkins University, Baltimore, MD); Menard, J. (Princeton University, Princeton, NJ); Mazzucato, E. (Princeton University, Princeton, NJ); Neumeyer, C. (Princeton University, Princeton, NJ); Nelson, B.A. (University of Washington, Seattle, WA); Lee, K. (University of California, Davis, CA); Manickam, J. (Princeton University, Princeton, NJ)

2004-06-01

320

Mitigation of rotational instability of high-beta field-reversed configuration by double-sided magnetized plasmoid injection  

NASA Astrophysics Data System (ADS)

Active control of destructive rotational instability in a high-beta field-reversed configuration (FRC) plasma was demonstrated by using double-sided plasmoid injection technique. The elliptical deformation of the FRC's cross section was mitigated as a result of substantial suppression of spontaneous spin-up by the plasmoid injection. It was found that the injected plasmoid provided better stability against the rotational mode, suggesting that the compensation of the FRC's decaying magnetic flux might help to suppress its spin-up.

Itagaki, H.; Asai, T.; Inomoto, M.; Takahashi, Ts.

2014-03-01

321

Finite beta effects on low- and high-frequency magnetosonic waves in a two-ion-species plasma  

SciTech Connect

A magnetosonic wave propagating perpendicular to a magnetic field in a two-ion-species plasma has two branches, high-frequency and low-frequency modes. The finite beta effects on these modes are analyzed theoretically on the basis of the three-fluid model with finite ion and electron pressures. First, it is shown that the Korteweg-de Vries (KdV) equation for the low-frequency mode is valid for amplitudes ?high-frequency mode are derived, including ? as a factor. In addition, the theory for heavy ion acceleration by the high-frequency mode pulse and the pulse damping due to this energy transfer in a finite beta plasma are presented.

Toida, Mieko; Aota, Yukio [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan)] [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan)

2013-08-15

322

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

323

Stimulated scattering in laser driven fusion and high energy density physics experiments  

NASA Astrophysics Data System (ADS)

In laser driven fusion and high energy density physics experiments, one often encounters a k?D range of 0.15 < k?D < 0.5, where stimulated Raman scattering (SRS) is active (k is the initial electron plasma wave number and ?D is the Debye length). Using particle-in-cell simulations, the SRS reflectivity is found to scale as (k?D)-4 for k?D ? 0.3 where electron trapping effects dominate SRS saturation; the reflectivity scaling deviates from the above for k?D < 0.3 when Langmuir decay instability (LDI) is present. The SRS risk is shown to be highest for k?D between 0.2 and 0.3. SRS re-scattering processes are found to be unimportant under conditions relevant to ignition experiments at the National Ignition Facility (NIF). Large-scale simulations of the hohlraum plasma show that the SRS wavelength spectrum peaks below 600 nm, consistent with most measured NIF spectra, and that nonlinear trapping in the presence of plasma gradients determines the SRS spectral peak. Collisional effects on SRS, stimulated Brillouin scattering (SBS), LDI, and re-scatter, together with three dimensional effects, are examined. Effects of collisions are found to include de-trapping as well as cross-speckle electron temperature variation from collisional heating, the latter of which reduces gain, introduces a positive frequency shift that counters the trapping-induced negative frequency shift, and affects SRS and SBS saturation. Bowing and breakup of ion-acoustic wavefronts saturate SBS and cause a dramatic, sharp decrease in SBS reflectivity. Mitigation of SRS and SBS in the strongly nonlinear trapping regime is discussed.

Yin, L.; Albright, B. J.; Rose, H. A.; Montgomery, D. S.; Kline, J. L.; Kirkwood, R. K.; Milovich, J.; Finnegan, S. M.; Bergen, B.; Bowers, K. J.

2014-09-01

324

A high performance sensorimotor beta rhythm-based brain computer interface associated with human natural motor behavior  

NASA Astrophysics Data System (ADS)

To explore the reliability of a high performance brain-computer interface (BCI) using non-invasive EEG signals associated with human natural motor behavior does not require extensive training. We propose a new BCI method, where users perform either sustaining or stopping a motor task with time locking to a predefined time window. Nine healthy volunteers, one stroke survivor with right-sided hemiparesis and one patient with amyotrophic lateral sclerosis (ALS) participated in this study. Subjects did not receive BCI training before participating in this study. We investigated tasks of both physical movement and motor imagery. The surface Laplacian derivation was used for enhancing EEG spatial resolution. A model-free threshold setting method was used for the classification of motor intentions. The performance of the proposed BCI was validated by an online sequential binary-cursor-control game for two-dimensional cursor movement. Event-related desynchronization and synchronization were observed when subjects sustained or stopped either motor execution or motor imagery. Feature analysis showed that EEG beta band activity over sensorimotor area provided the largest discrimination. With simple model-free classification of beta band EEG activity from a single electrode (with surface Laplacian derivation), the online classifications of the EEG activity with motor execution/motor imagery were: >90%/~80% for six healthy volunteers, >80%/~80% for the stroke patient and ~90%/~80% for the ALS patient. The EEG activities of the other three healthy volunteers were not classifiable. The sensorimotor beta rhythm of EEG associated with human natural motor behavior can be used for a reliable and high performance BCI for both healthy subjects and patients with neurological disorders. Significance: The proposed new non-invasive BCI method highlights a practical BCI for clinical applications, where the user does not require extensive training.

Bai, Ou; Lin, Peter; Vorbach, Sherry; Floeter, Mary Kay; Hattori, Noriaki; Hallett, Mark

2008-03-01

325

A novel beta-agarase with high pH stability from marine Agarivorans sp. LQ48.  

PubMed

A novel endo-type beta-agarase gene, agaA, was cloned from a newly isolated marine bacterium, Agarivorans sp. LQ48. It encodes a protein of 457 amino acids with a calculated molecular mass of 51.2 kDa. The deduced protein contains a typical N-terminal signal peptide of 25 amino acid residues, followed by a catalytic module, which is homologous to that of glycoside hydrolase family 16. A sequence similar to a carbohydrate-binding module is found in the C-terminal region of the enzyme. The overall amino acid sequence shares a highest identity of 73% with the sequence of beta-agarase AgaB from Pseudoalteromonas sp. strain CY24. The mature agarase was highly expressed extracellularly in Escherichia coli. At pH 7.0 and 40 degrees C, the purified recombinant AgaA had a high specific activity of 349.3 micromol min(-1) mg(-1), a K(m) of 3.9 mg ml(-1), and a V(max) of 909.1 micromol min(-1) mg(-1) for agarose. The recombinant enzyme hydrolyzed the beta-1,4-glycosidic linkages of agarose, yielding neoagarotetraose and neoagarohexaose as the main products. Enzyme activity analysis revealed that the optimal temperature and pH of the recombinant AgaA were 40 degrees C and 7.0, respectively. Notably, AgaA still retained more than 95% activity after incubation at pH 3.0-11.0 for 1 h, a characteristic much different from other agarases reported. It is the first agarase identified to have so wide a pH range stability. This favorable property could make AgaA to be attractive to the food, cosmetic, and medical industrial applications. PMID:19484308

Long, Mengxian; Yu, Ziniu; Xu, Xun

2010-02-01

326

High resolution transmission electron microscopy study of the hardening mechanism through phase separation in a beta-Ti-35Nb-7Zr-5Ta alloy for implant applications.  

PubMed

beta-Ti alloys are highly attractive metallic materials for biomedical applications due to their high specific strength, high corrosion resistance and excellent biocompatibility, including low elastic modulus. This work aims to clarify the hardening mechanism of a beta-Ti-Nb-Zr-Ta alloy using different characterization techniques. Ingots (50 g) of Ti-35Nb-7Zr-5Ta (wt.%) alloy were arc furnace melted in an Ar((g)) atmosphere, homogenized, hot rolled, solubilized and finally aged at several temperatures from 200 to 700 degrees C for 4 h. Microstructure characterization was performed using X-ray diffraction, optical microscopy, scanning and high resolution transmission electron microscopy (HR-TEM). The 4 h aging showed that the highest hardness values were found when aged at 400 degrees C and the HR-TEM images confirmed splitting of spots on the Fourier space map, which indicated the presence of a coherent interface between separated phases (beta and beta') and explains the hardening mechanism of the alloy. Through geometric phase analysis analysis, using the HR-TEM image, the localized strain map showed 5-10 nm domains of the beta and beta' phases. The combination of suitable values of yield strength, hardness and low Young's modulus makes Ti-35Nb-7Zr-5Ta alloy suitable for medical applications as a metallic orthopedic implant. PMID:19913645

Afonso, Conrado R M; Ferrandini, Peterson L; Ramirez, Antonio J; Caram, Rubens

2010-04-01

327

Identifying heavy-ion-beam fusion design and system features with high economic leverage  

SciTech Connect

We have conducted parametric economic studies for heavy-ion-beam fusion electric power plants. We examined the effects on the cost of electricity of several design parameters: maximum achievable chamber pulse rate, driver cost, target gain, and electric conversion efficiency, and net electric power. We found with reasonable assumptions on driver cost, target gain, and electric conversion efficiency, a 2 to 3 GWe heavy-ion-beam fusion power plant, with a chamber pulse rate of 5 to 10 Hz, can be competitive with nuclear and coal power plants.

Meier, W.R.; Hogan, W.J.

1985-03-03

328

High level transient production of recombinant antibodies and antibody fusion proteins in HEK293 cells  

PubMed Central

Background The demand of monospecific high affinity binding reagents, particularly monoclonal antibodies, has been steadily increasing over the last years. Enhanced throughput of antibody generation has been addressed by optimizing in vitro selection using phage display which moved the major bottleneck to the production and purification of recombinant antibodies in an end-user friendly format. Single chain (sc)Fv antibody fragments require additional tags for detection and are not as suitable as immunoglobulins (Ig)G in many immunoassays. In contrast, the bivalent scFv-Fc antibody format shares many properties with IgG and has a very high application compatibility. Results In this study transient expression of scFv-Fc antibodies in human embryonic kidney (HEK) 293 cells was optimized. Production levels of 10-20mg/L scFv-Fc antibody were achieved in adherent HEK293T cells. Employment of HEK293-6E suspension cells expressing a truncated variant of the Epstein Barr virus (EBV) nuclear antigen (EBNA) 1 in combination with production under serum free conditions increased the volumetric yield up to 10-fold to more than 140mg/L scFv-Fc antibody. After vector optimization and process optimization the yield of an scFv-Fc antibody and a cytotoxic antibody-RNase fusion protein further increased 3-4-fold to more than 450mg/L. Finally, an entirely new mammalian expression vector was constructed for single step in frame cloning of scFv genes from antibody phage display libraries. Transient expression of more than 20 different scFv-Fc antibodies resulted in volumetric yields of up to 600mg/L and 400mg/L in average. Conclusion Transient production of recombinant scFv-Fc antibodies in HEK293-6E in combination with optimized vectors and fed batch shake flasks cultivation is efficient and robust, and integrates well into a high-throughput recombinant antibody generation pipeline. PMID:23802841

2013-01-01

329

Development of a magnetohydrodynamic code for axisymmetric, high-. beta. plasmas with complex magnetic fields  

SciTech Connect

The Topolotron is an axisymmetric, toroidal magnetic fusion concept in which two-dimensional effects are important, as well as all three magnetic field components. The particular MHD model employed is basically the one-fluid, two-temperature model using classical Braginskii transport with viscous effects ignored. The model is augmented by Saha-Boltzmann dissociation and partial ionization physics, a simple radiation loss mechanism, and an additional resistivity due to electron-neutral collisions. While retaining all velocity and magnetic field components, the assumption of axisymmetry is made, and the resulting equations are expanded in cylindrical coordinates. The major approximation technique is then applied: spline collocation, which reduces these equations to a set of ordinary differential equations.

Cook, G.O. Jr.

1982-12-01

330

Highly enantioselective electrophilic amination and michael addition of cyclic beta-ketoesters induced by lanthanides and (S,S)-ip-pybox: the mechanism.  

PubMed

High enantioselection is obtained in Michael additions of cyclic beta-ketoesters in the presence of lanthanium triflates and (S,S)-ip-pybox. Intermediates based on simultaneous coordination of the lanthanide to both (S,S)-ip-box and beta-ketoester (in keto and enolate forms) are detected by means of ESI mass spectrometry and NMR experiments, and a possible mechanism is proposed through theoretical calculations. PMID:17315933

Comelles, Josep; Pericas, Alex; Moreno-Maas, Marcial; Vallribera, Adelina; Drudis-Sol, Gal; Lledos, Agusti; Parella, Teodor; Roglans, Anna; Garca-Granda, Santiago; Roces-Fernndez, Laura

2007-03-16

331

Apolipoprotein E: High-Avidity Binding to beta-Amyloid and Increased Frequency of Type 4 Allele in Late-Onset Familial Alzheimer Disease  

Microsoft Academic Search

Apolipoprotein E is immunochemically localized to the senile plaques, vascular amyloid, and neurofibrillary tangles of Alzheimer disease. In vitro, apolipoprotein E in cerebrospinal fluid binds to synthetic beta A4 peptide (the primary constituent of the senile plaque) with high avidity. Amino acids 12-28 of the beta A4 peptide are required. The gene for apolipoprotein E is located on chromosome 19q13.2,

Warren J. Strittmatter; Ann M. Saunders; Donald Schmechel; Margaret Pericak-Vance; Jan Enghild; Guy S. Salvesen; Allen D. Roses

1993-01-01

332

DEVELOPMENT, PRODUCTION AND TESTS OF PROTOTYPE SUPERCONDUCTING CAVITIES FOR THE HIGH BETA SECTION OF THE ISAC-II HEAVY ION ACCELERATOR AT TRIUMF  

Microsoft Academic Search

The medium beta section of the ISAC-II heavy ion superconducting linear accelerator, consisting of 20 cavities, has been in operation at TRIUMF since 2006. The high beta section of the accelerator, consisting of an additional twenty cavities, is currently under development and is scheduled for completion in 2009. The cavity is a superconducting bulk Niobium two-gap quarter-wave resonator for frequency

V. Zvyagintsev; R. E. Laxdal; R. Dawson; K. Fong; A. Grasselino; P. Harmer; M. Marchetto

333

ARC: A compact, high-field, fusion nuclear science facility and demonstration power plant with demountable magnets  

E-print Network

The affordable, robust, compact (ARC) reactor conceptual design study aims to reduce the size, cost, and complexity of a combined fusion nuclear science facility (FNSF) and demonstration fusion Pilot power plant. ARC is a 270 MWe tokamak reactor with a major radius of 3.3 m, a minor radius of 1.1 m, and an on-axis magnetic field of 9.2 T. ARC has rare earth barium copper oxide (REBCO) superconducting toroidal field coils, which have joints to enable disassembly. This allows the vacuum vessel to be replaced quickly, mitigating first wall survivability concerns, and permits a single device to test many vacuum vessel designs and divertor materials. The design point has a plasma fusion gain of Q_p~13.6, yet is fully non-inductive, with a modest bootstrap fraction of only ~63%. Thus ARC offers a high power gain with relatively large external control of the current profile. This highly attractive combination is enabled by the ~23 T peak field on coil with newly available REBCO superconductor technology. External cu...

Sorbom, B N; Palmer, T R; Mangiarotti, F J; Sierchio, J M; Bonoli, P; Kasten, C; Sutherland, D A; Barnard, H S; Haakonsen, C B; Goh, J; Sung, C; Whyte, D G

2014-01-01

334

High-throughput deterministic single-cell encapsulation and droplet pairing, fusion, and shrinkage in a single microfluidic device.  

PubMed

In this article, we present a microfluidic device capable of successive high-yield single-cell encapsulation in droplets, with additional droplet pairing, fusion, and shrinkage. Deterministic single-cell encapsulation is realized using Dean-coupled inertial ordering of cells in a Yin-Yang-shaped curved microchannel using a double T-junction, with a frequency over 2000 Hz, followed by controlled droplet pairing with a 100% success rate. Subsequently, droplet fusion is realized using electrical actuation resulting in electro-coalescence of two droplets, each containing a single HL60 cell, with 95% efficiency. Finally, volume reduction of the fused droplet up to 75% is achieved by a triple pitchfork structure. This droplet volume reduction is necessary to obtain close cell-cell membrane contact necessary for final cell electrofusion, leading to hybridoma formation, which is the ultimate aim of this research. PMID:23856757

Schoeman, Rogier M; Kemna, Evelien W M; Wolbers, Floor; van den Berg, Albert

2014-02-01

335

High efficiency microfluidic beta detector for pharmacokinetic studies in small animals  

NASA Astrophysics Data System (ADS)

New radiotracers are continuously being developed to improve diagnostic efficiency using Single Photon Emission Computed Tomography (SPECT) or Positron Emission Tomography (PET). The characterization of their pharmacokinetics requires blood radioactivity monitoring over time during the scan and is very challenging in small animals because of the low volume of blood available. In this work, a prototype microfluidic blood counter made of a microchannel atop a silicon substrate containing PIN photodiodes is proposed to improve beta detection efficiency in a small volume by eliminating unnecessary interfaces between fluid and detector. A flat rectangular-shaped epoxy channel, 36 ?m1.26 mm cross section and 31.5 mm in length, was microfabricated over a die containing an array of 22 mm 2 PIN photodiodes, leaving only a few micrometers of epoxy floor layer between the fluid and the photodiode sensitive surface. This geometry leads to a quasi 2D source, optimizing geometrical detection efficiency that was estimated at 41% using solid angle calculation. CV- IV measurements were made at each fabrication step to confirm that the microchannel components had no significant effects on the diodes' electrical characteristics. The chip was wire-bonded to a PCB and connected to charge sensitive preamplifier and amplifier modules for pulse shaping. Energy spectra recorded for different isotopes showed continuous beta distribution for PET isotopes and monoenergetic conversion electron peaks for 99mTc. Absolute sensitivity was determined for the most popular PET and SPECT radioisotopes and ranged from 26% to 33% for PET tracers ( 18F, 13N, 11C, 68Ga) and more than 2% for 99mTc. Input functions were successfully simulated with 18F, confirming the setup's suitability for pharmacokinetic modeling of PET and SPECT radiotracers in animal experiments. By using standard materials and procedures, the fabrication process is well suited to on-chip microfluidic functionality, allowing full characterization of new radiotracers.

Convert, Laurence; Girard-Baril, Frdrique; Renaudin, Alan; Grondin, tienne; Jaouad, Abdelatif; Aimez, Vincent; Charette, Paul; Lecomte, Roger

2011-10-01

336

Wild topology, hyperbolic geometry and fusion algebra of high energy particle physics  

Microsoft Academic Search

The relation between Wild Topology, Hyperbolic Geometry and Fusion Algebra on the one side and the charge and coupling constants of the standard model and quantum gravity on the other is examined.The close connection found between E(?) theory and the Topological theory of four manifolds as well as the theory of fundamental groups is elucidated using various classical theories and

M. S. El Naschie

2002-01-01

337

The promise of magnetized fuel: High gain in inertial confinement fusion  

Microsoft Academic Search

At the third International Conference on Emerging Nuclear Energy Systems, we presented computational results which suggested that breakeven experiments in inertial confinement fusion (ICF) may be possible with existing driver technology. Our computations used a simple zero-dimensional model to survey the parameter space available for magnetized fuel. The survey predicted the existence of a totally new region in parameter space

I. R. Lindemuth; R. C. Kirkpatrick

1991-01-01

338

Development of high-power solid state laser for inertial fusion energy driver  

Microsoft Academic Search

The design study of the laser fusion power plant KOYO has been conducted as a joint program of universities, national laboratories, and industries in Japan and also with international collaborations. In the design of KOYO, the gain scaling of direct drive implosion with 0.35 micrometers wavelength laser light is used. A driver of diode pumped solid state laser generates 4

Kunio Yoshida; Masanobu Yamanaka; Masahiro Nakatsuka; Takatomo Sasaki; Sadao Nakai

1997-01-01

339

EXPLORING POSSIBLE HIGH FUSION POWER REGIMES WITH THE IFS-PPPL MODEL  

E-print Network

(U. Md), M. A. Beer (PPPL), M. Kotschenreuther (U. Texas) Workshop on Burning Plasma Sciences.23)] (1 - (a/R)2 )2 (1.17 - 0.65a/R) 2 AiR 2a (Hammett, Dorland, Kotschenreuther, Beer, PPPL-3360 (1999, Beer, PPPL-3360 (1999)) #12;Sensitivity of Fusion Power to Some Assumptions Baseline assumptions: IFS

340

EXPLORING POSSIBLE HIGH FUSION POWER REGIMES WITH THE IFS-PPPL MODEL  

E-print Network

(U. Md), M. A. Beer (PPPL), M. Kotschenreuther (U. Texas) Some of this discussed by D. Meade (PPPL.23)] (1 - (a/R)2 )2 (1.17 - 0.65a/R) 2 AiR 2a (Hammett, Dorland, Kotschenreuther, Beer, PPPL-3360 (1999, Beer, PPPL-3360 (1999)) #12;Sensitivity of Fusion Power to Some Assumptions Baseline assumptions: IFS

341

EXPLORING POSSIBLE HIGH FUSION POWER REGIMES WITH THE IFS-PPPL MODEL  

E-print Network

(U. Md), M. A. Beer (PPPL), M. Kotschenreuther (U. Texas) Some of this presented by D. Meade (PPPL.23)] (1 - (a/R)2 )2 (1.17 - 0.65a/R) 2 AiR 2a (Hammett, Dorland, Kotschenreuther, Beer, PPPL-3360 (1999, Beer, PPPL-3360 (1999)) #12;Sensitivity of Fusion Power to Some Assumptions Baseline assumptions: IFS

Hammett, Greg

342

Multisensor Data Fusion for High Quality Data Analysis and Processing in Measurement and Instrumentation  

Microsoft Academic Search

Multisensor data fusion (MDF) is an emerging technology to fuse data from multiple sensors in order to make a more accurate estimation of the environment through measurement and detection. Applications of MDF cross a wide spectrum in military and civilian areas. With the rapid evolution of computers and the proliferation of micro-mechanical\\/electrical systems sensors, the utilization of MDF is being

Yan-bo Huang; Yu-bin Lan; W. C. Hoffmann; R. E. Lacey

2007-01-01

343

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

344

Beta Diffusion Trees Creighton Heaukulani  

E-print Network

- clustered factor analysis model with the beta dif- fusion tree and how to perform inference over the random subsets of objects, known as a feature allocation. The generative process for the tree is defined in terms of particles (representing the objects) diffusing in some continuous space, analogously to the Dirichlet

Edinburgh, University of

345

Lateral Lumbar Interbody Fusion for the Correction of Spondylolisthesis and Adult Degenerative Scoliosis in High-Risk Patients: Early Radiographic Results and Complications  

PubMed Central

Background Lateral lumbar interbody fusion (LLIF) is not associated with many of the complications seen in other interbody fusion techniques. This study used computed tomography (CT) scans, the radiographic gold standard, to assess interbody fusion rates achieved utilizing the LLIF technique in high-risk patients. Methods We performed a retrospective review of patients who underwent LLIF between January 2008 and July 2013. Forty-nine patients underwent nonstaged or staged LLIF on 119 levels with posterior correction and augmentation. Per protocol, patients received CT scans at their 1-year follow-up. Of the 49 patients, 21 patients with LLIF intervention on 54 levels met inclusion criteria. Two board-certified musculoskeletal radiologists and the senior surgeon (JZ) assessed fusion. Results Of the 21 patients, 6 patients had had previous lumbar surgery, and the cohort's comorbidities included osteoporosis, diabetes, obesity, and smoking, among others. Postoperative complications occurred in 12 (57.1%) patients and included anterior thigh pain and weakness in 6 patients, all of which resolved by 6 months. Two cases of proximal junctional kyphosis occurred, along with 1 case of hardware pullout. Two cases of abdominal atonia occurred. By CT scan assessment, each radiologist found fusion was achieved in 53 of 54 levels (98%). The radiologists' findings were in agreement with the senior surgeon. Conclusion Several studies have evaluated LLIF fusion and reported fusion rates between 88%-96%. Our results demonstrate high fusion rates using this technique, despite multiple comorbidities in the patient population. Spanning the ring apophysis with large LLIF cages along with supplemental posterior pedicle screw augmentation can enhance stability of the fusion segment and increase fusion rates. PMID:24688329

Waddell, Brad; Briski, David; Qadir, Rabah; Godoy, Gustavo; Houston, Allison Howard; Rudman, Ernest; Zavatsky, Joseph

2014-01-01

346

Supplementation of the diet with high-viscosity beta-glucan results in enrichment for lactobacilli in the rat cecum.  

PubMed

BBn (BioBreeding) rats were fed casein-based diets supplemented with barley flour, oatmeal flour, cellulose, or barley beta-glucans of high [HV] or low viscosity [LV] in order to measure the prebiotic effects of these different sources of dietary fiber. The dietary impact on the composition of the cecal microbiota was determined by the generation of denaturing gradient gel electrophoresis (DGGE) profiles of PCR-amplified 16S rRNA gene sequences. The DGGE profiles produced from the cecal microbiota of rats within each dietary group were similar, but consensus profiles generated from pooled bacterial DNAs showed differences between rat groups. Animals fed HV glucans (HV-fed rats) had DGGE consensus profiles that were 30% dissimilar from those of the other rat groups. A 16S rRNA gene fragment that was more conspicuous in the profiles of HV-fed animals than in those of cellulose-fed rats had sequence identity with Lactobacillus acidophilus. Measurements of L. acidophilus rRNA abundance (DNA-RNA hybridization), the preparation of cloned 16S rRNA gene libraries, and the enumeration of Lactobacillus cells (fluorescent in situ hybridization) showed that lactobacilli formed a greater proportion of the cecal microbiota in HV-fed rats. In vitro experiments confirmed that some lactobacilli utilize oligosaccharides (degree of polymerization, 3 or 4) present in beta-glucan hydrolysates. The results of this study have relevance to the use of purified beta-glucan products as dietary supplements for human consumption. PMID:16517639

Snart, Jennifer; Bibiloni, Rodrigo; Grayson, Teresa; Lay, Christophe; Zhang, Haiyan; Allison, Gwen E; Laverdiere, Julie K; Temelli, Feral; Vasanthan, Thavaratnam; Bell, Rhonda; Tannock, Gerald W

2006-03-01

347

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

348

High Prevalence of Extended-Spectrum Beta Lactamases among Salmonella enterica Typhimurium Isolates from Pediatric Patients with Diarrhea in China  

PubMed Central

We investigated the extended-spectrum beta lactamases among 62 Salmonella enterica Typhimurium isolates recovered from children with diarrhea in a Chinese pediatric hospital. A large proportion of S. enterica Typhimurium isolates were resistant to multiple antimicrobial agents, including ampicillin (90.3%), tetracycline (80.6%), trimethoprim/sulfamethoxazole (74.2%), chloramphenicol (66.1%), cefotaxime (27.4%). Forty-nine (79.0%) of S. enterica Typhimurium isolates were positive for blaTEM-1b and resistant to ampicillin. Thirteen S. enterica Typhimurium isolates (21.0%) were positive for blaCTX-M-1-group and blaCTX-M-9-group, and all isolates harboring blaCTX-M genes were positive for ISEcp1. Two main clones (PFGE type A and D) accounted for nearly 70% of S. enterica Typhimurium isolates, and 7 CTX-M-producing isolates belonged to PFGE type D. Collectively, our data reveal multi-drug resistance and a high prevalence of extended spectrum beta lactamases among S. enterica Typhimurium isolates from children in China. In addition, we report the first identification of blaCTX-M-55 within Salmonella spp. Our data also suggest that clonal spread is responsible for the dissemination of S. enterica Typhimurium isolates. PMID:21390297

Yu, Fangyou; Chen, Qiang; Yu, Xiaojun; Li, Qiaoqiao; Ding, Baixing; Yang, Lehe; Chen, Cong; Qin, Zhiqiang; Parsons, Chris; Zhang, Xueqing; Huang, Jinwei; Luo, Yun; Wang, Liangxing; Pan, Jingye

2011-01-01

349

An overview of LLNL high-energy short-pulse technology for advanced radiography of laser fusion experiments  

NASA Astrophysics Data System (ADS)

The technical challenges and motivations for high-energy, short-pulse generation with NIF and possibly other large-scale Nd : glass lasers are reviewed. High-energy short-pulse generation (multi-kilojoule, picosecond pulses) will be possible via the adaptation of chirped pulse amplification laser techniques on NIF. Development of metre-scale, high-efficiency, high-damage-threshold final optics is a key technical challenge. In addition, deployment of high energy petawatt (HEPW) pulses on NIF is constrained by existing laser infrastructure and requires new, compact compressor designs and short-pulse, fibre-based, seed-laser systems. The key motivations for HEPW pulses on NIF is briefly outlined and includes high-energy, x-ray radiography, proton beam radiography, proton isochoric heating and tests of the fast ignitor concept for inertial confinement fusion.

Barty, C. P. J.; Key, M.; Britten, J.; Beach, R.; Beer, G.; Brown, C.; Bryan, S.; Caird, J.; Carlson, T.; Crane, J.; Dawson, J.; Erlandson, A. C.; Fittinghoff, D.; Hermann, M.; Hoaglan, C.; Iyer, A.; Jones, L., II; Jovanovic, I.; Komashko, A.; Landen, O.; Liao, Z.; Molander, W.; Mitchell, S.; Moses, E.; Nielsen, N.; Nguyen, H.-H.; Nissen, J.; Payne, S.; Pennington, D.; Risinger, L.; Rushford, M.; Skulina, K.; Spaeth, M.; Stuart, B.; Tietbohl, G.; Wattellier, B.

2004-12-01

350

Inhibition of high-molecular-weight-(1-->3)-beta-D-glucan-dependent activation of a limulus coagulation factor G by laminaran oligosaccharides and curdlan degradation products.  

PubMed

Extensive surveys for the effects of various beta-D-glucans on the coagulation cascade in horseshoe crab amebocyte lysates showed that low-mol-wt-(1-->3)-beta-D-glucans and laminaran oligosaccharides inhibit the activation of a limulus coagulation factor G by high-mol-wt-(1-->3)-beta-D-glucans. The inhibitory properties are exclusively dependent upon their number-average mol wt (Mn) in a range of 342-58,100, which correspond to a degree of polymerization (dp) range of 2-359. The most effective is a laminaran dextrin of Mn 5800 (dp of 35-36), which causes 50% inhibition of factor G activation at a concentration of 3.16 ng/mL. The inhibition of the activation of factor G proportional to the concentration of the inhibitor, and the adsorption of factor G by inhibitory beta-D-glucan-conjugated cellulose suggested a high affinity of the inhibitory saccharides for the activator-recognition site of factor G. Branched (1-->6), (1-->3)-beta-D-glucans, laminarans, mixed linkage (1-->3), (1-->4)-beta-D-glucans, and partially substituted curdlan and laminaran were found to be inhibitory, possibly owing to clusters of consecutive (1-->3)-beta-D-glucopyranosyl residues as intrachain units. The inhibition appears to be related to the inability of the inhibitory (1-->3)-beta-D-glucans to form ordered conformations and to their tendency to take a random-coil structure in aqueous solution. PMID:8339297

Tanaka, S; Aketagawa, J; Takahashi, S; Shibata, Y; Tsumuraya, Y; Hashimoto, Y

1993-05-21

351

HES6 reverses nuclear reprogramming of insulin-producing cells following cell fusion  

SciTech Connect

To examine the mechanism by which growth-stimulated pancreatic {beta}-cells dedifferentiate, somatic cell fusions were performed between MIN6, a highly differentiated mouse insulinoma, and {beta}lox5, a cell line derived from human {beta}-cells which progressively dedifferentiated in culture. MIN6/{beta}lox5 somatic cells hybrids underwent silencing of insulin expression and a marked decline in PDX1, NeuroD, and MafA, indicating that {beta}lox5 expresses a dominant transacting factor(s) that represses {beta}-cell differentiation. Expression of Hes1, which inhibits endocrine differentiation was higher in hybrid cells than in parental MIN6 cells. Hes6, a repressor of Hes1, was highly expressed in primary {beta}-cells as well as MIN6, but was repressed in hybrids. Hes6 overexpression using a retroviral vector led to a decrease in Hes1 levels, an increase in {beta}-cell transcription factors and partial restoration of insulin expression. We conclude that the balance of Notch activators and inhibitors may play an important role in maintaining the {beta}-cell differentiated state.

Ball, Andrew J. [UCSD Department of Pediatrics, 9500 Gilman Drive, La Jolla, CA 92093-0816 (United States); Abrahamsson, Annelie E. [UCSD Department of Pediatrics, 9500 Gilman Drive, La Jolla, CA 92093-0816 (United States); Tyrberg, Bjoern [UCSD Department of Pediatrics, 9500 Gilman Drive, La Jolla, CA 92093-0816 (United States); Burnham Institute for Medical Research (United States); Itkin-Ansari, Pamela [UCSD Department of Pediatrics, 9500 Gilman Drive, La Jolla, CA 92093-0816 (United States); Burnham Institute for Medical Research (United States); Levine, Fred [UCSD Department of Pediatrics, 9500 Gilman Drive, La Jolla, CA 92093-0816 (United States); Burnham Institute for Medical Research (United States); E-mail: flevine@ucsd.edu

2007-04-06

352

Inertial Fusion: Strategy and Economic Potential.  

National Technical Information Service (NTIS)

Inertial fusion must demonstrate that the high target gains required for practical fusion energy can be achieved with driver energies not larger than a few megajoules. Before a multi-megajoule scale driver is constructed, inertial fusion must provide conv...

J. H. Nuckolls

1983-01-01

353

Driving high-gain shock-ignited inertial confinement fusion targets by green laser light  

NASA Astrophysics Data System (ADS)

Standard direct-drive inertial confinement fusion requires UV light irradiation in order to achieve ignition at total laser energy of the order of 1 MJ. The shock-ignition approach opens up the possibility of igniting fusion targets using green light by reducing the implosion velocity and laser-driven ablation pressure. An analytical model is derived, allowing to rescale UV-driven targets to green light. Gain in the range 100-200 is obtained for total laser energy in the range 1.5-3 MJ. With respect to the original UV design, the rescaled targets are less sensitive to irradiation asymmetries and hydrodynamic instabilities, while operating in the same laser-plasma interaction regime.

Atzeni, Stefano; Marocchino, Alberto; Schiavi, Angelo

2012-09-01

354

Simulation studies of hydrodynamic aspects of magneto-inertial fusion and high order adaptive algorithms for Maxwell equations  

NASA Astrophysics Data System (ADS)

Three-dimensional simulations of the formation and implosion of plasma liners for the Plasma Jet Induced Magneto Inertial Fusion (PJMIF) have been performed using multiscale simulation technique based on the FronTier code. In the PJMIF concept, a plasma liner, formed by merging of a large number of radial, highly supersonic plasma jets, implodes on the target in the form of two compact plasma toroids, and compresses it to conditions of the nuclear fusion ignition. The propagation of a single jet with Mach number 60 from the plasma gun to the merging point was studied using the FronTier code. The simulation result was used as input to the 3D jet merger problem. The merger of 144, 125, and 625 jets and the formation and heating of plasma liner by compression waves have been studied and compared with recent theoretical predictions. The main result of the study is the prediction of the average Mach number reduction and the description of the liner structure and properties. We have also compared the effect of different merging radii. Spherically symmetric simulations of the implosion of plasma liners and compression of plasma targets have also been performed using the method of front tracking. The cases of single deuterium and xenon liners and double layer deuterium - xenon liners compressing various deuterium-tritium targets have been investigated, optimized for maximum fusion energy gains, and compared with theoretical predictions and scaling laws of [P. Parks, On the efficacy of imploding plasma liners for magnetized fusion target compression, Phys. Plasmas 15, 062506 (2008)]. In agreement with the theory, the fusion gain was significantly below unity for deuterium - tritium targets compressed by Mach 60 deuterium liners. In the most optimal setup for a given chamber size that contained a target with the initial radius of 20 cm compressed by 10 cm thick, Mach 60 xenon liner, the target ignition and fusion energy gain of 10 was achieved. Simulations also showed that composite deuterium - xenon liners reduce the energy gain due to lower target compression rates. The effect of heating of targets by alpha particles on the fusion energy gain has also been investigated. The study of the dependence of the ram pressure amplification on radial compressibility showed a good agreement with the theory. The study concludes that a liner with higher Mach number and lower adiabatic index gamma (the radio of specific heats) will generate higher ram pressure amplification and higher fusion energy gain. We implemented a second order embedded boundary method for the Maxwell equations in geometrically complex domains. The numerical scheme is second order in both space and time. Comparing to the first order stair-step approximation of complex geometries within the FDTD method, this method can avoid spurious solution introduced by the stair step approximation. Unlike the finite element method and the FE-FD hybrid method, no triangulation is needed for this scheme. This method preserves the simplicity of the embedded boundary method and it is easy to implement. We will also propose a conservative (symplectic) fourth order scheme for uniform geometry boundary.

Wu, Lingling

355

Transmutation of high-level fission products and actinides in a laser-driven fusion reactor  

Microsoft Academic Search

Incineration of [sup 90]Sr and [sup 137]Cs b thermal or fast neutrons is a very difficult problem. A 14-MeV neutron source based on intertial confinement fusion is a more appropriate choice. For the first time, the contribution of the (n,2n) reaction to incineration is revealed. The energy and nuclei balance for a system of several nuclear power plants and a

N. Basov; V. B. Rozanov; N. I. Belousov; P. A. Grishunin; V. V. Kharitonov; V. I. Subbotin

1992-01-01

356

Simulations of alpha parameters in a TFTR DT supershot with high fusion power  

Microsoft Academic Search

A TFTR supershot with a plasma current of 2.5 MA, a neutral beam heating power of 33.7 MW and a peak DT fusion power of 7.5 MW is studied using the TRANSP plasma analysis code. Simulations of alpha parameters such as the alpha heating, pressure and distributions in energy and v1\\/v are given. The effects of toroidal ripple and mixing

R. V. Budny; M. G. Bell; A. C. Janos; D. L. Jassby; L. C. Johnson; D. K. Mansfield; D. C. McCune; M. H. Redi; J. F. Schivell; G. Taylor; T. B. Terpstra; M. C. Zarnstorff; S. J. Zweben

1995-01-01

357

High Energy Electron Confinement in a Magnetic Cusp Configuration  

E-print Network

We report experimental results validating the concept that plasma confinement is enhanced in a magnetic cusp configuration when beta (plasma pressure/magnetic field pressure) is order of unity. This enhancement is required for a fusion power reactor based on cusp confinement to be feasible. The magnetic cusp configuration possesses a critical advantage: the plasma is stable to large scale perturbations. However, early work indicated that plasma loss rates in a reactor based on a cusp configuration were too large for net power production. Grad and others theorized that at high beta a sharp boundary would form between the plasma and the magnetic field, leading to substantially smaller loss rates. The current experiment validates this theoretical conjecture for the first time and represents critical progress toward the Polywell fusion concept which combines a high beta cusp configuration with an electrostatic fusion for a compact, economical, power-producing nuclear fusion reactor.

Park, Jaeyoung; Sieck, Paul E; Offermann, Dustin T; Skillicorn, Michael; Sanchez, Andrew; Davis, Kevin; Alderson, Eric; Lapenta, Giovanni

2014-01-01

358

Intein-mediated fusion expression, high efficient refolding, and one-step purification of gelonin toxin.  

PubMed

An open reading frame of gelonin (Gel), one of ribosome inactivating proteins, was inserted into the vector pBSL-C which contains the coding region of chitin binding domain (CBD)-intein, resulting in the fusion expression of CBD-intein-Gel in Escherichia coli BL21 (DE3) by the induction of IPTG. The fusion product formed an aggregate of the misfolded protein, commonly referred to as inclusion bodies (IBs). The IBs were denatured and then refolded by step-wise dialysis. About 69% fusion protein was in vitro refolded to native state in the presence of GSSG and GSH as monitored by size-exclusion HPLC. The refolded CBD-intein-Gel was loaded onto chitin beads column equilibrated with 10 mM Tris buffer, 500 mM NaCl, pH 8.5, and about 2.4 mgGel/L culture with 96% homogeneity was directly eluted from the captured column by incubation at 25 degrees C under pH 6.5 for 48 h based on intein C-terminal self-cleavage. Western blot, ELISA, and in vitro inhibition of protein synthesis demonstrated that the bioactivity of recombinant Gel was comparable to that of native Gel purified from seeds. This implied that the purified Gel by this method is biologically active and suitable for further studies. PMID:15358358

Guo, Chenyun; Li, Zhuoyu; Shi, Yawei; Xu, Mingqun; Wise, John G; Trommer, Wolfgong E; Yuan, Jingming

2004-10-01

359

Beta-manganese dioxide nanorods for sufficient high-temperature electromagnetic interference shielding in X-band  

NASA Astrophysics Data System (ADS)

As the development of electronic and communication technology, electromagnetic interference (EMI) shielding and attenuation is an effective strategy to ensure the operation of the electronic devices. Among the materials for high-performance shielding in aerospace industry and related high-temperature working environment, the thermally stable metal oxide semiconductors with narrow band gap are promising candidates. In this work, beta-manganese dioxide ( ?-MnO2) nanorods were synthesized by a hydrothermal method. The bulk materials of the ?-MnO2 were fabricated to evaluate the EMI shielding performance in the temperature range of 20-500 C between 8.2 and 12.4 GHz (X-band). To understand the mechanisms of high-temperature EMI shielding, the contribution of reflection and absorption to EMI shielding was discussed based on temperature-dependent electrical properties and complex permittivity. Highly sufficient shielding effectiveness greater than 20 dB was observed over all the investigated range, suggesting ?-MnO2 nanorods as promising candidates for high-temperature EMI shielding. The results have also established a platform to develop high-temperature EMI shielding materials based on nanoscale semiconductors.

Song, Wei-Li; Cao, Mao-Sheng; Hou, Zhi-Ling; Lu, Ming-Ming; Wang, Chan-Yuan; Yuan, Jie; Fan, Li-Zhen

2014-09-01

360

(Fusion energy research)  

SciTech Connect

This report discusses the following topics: principal parameters achieved in experimental devices (FY88); tokamak fusion test reactor; Princeton beta Experiment-Modification; S-1 Spheromak; current drive experiment; x-ray laser studies; spacecraft glow experiment; plasma deposition and etching of thin films; theoretical plasma; tokamak modeling; compact ignition tokamak; international thermonuclear experimental reactor; Engineering Department; Project Planning and Safety Office; quality assurance and reliability; and technology transfer.

Phillips, C.A. (ed.)

1988-01-01

361

Facility for high-heat flux testing of irradiated fusion materials and components using infrared plasma arc lamps  

NASA Astrophysics Data System (ADS)

A new high-heat flux testing (HHFT) facility using water-wall stabilized high-power high-pressure argon plasma arc lamps (PALs) has been developed for fusion applications. It can accommodate irradiated plasma facing component materials and sub-size mock-up divertor components. Two PALs currently available at Oak Ridge National Laboratory can provide maximum incident heat fluxes of 4.2 and 27 MW m-2, which are prototypic of fusion steady state heat flux conditions, over a heated area of 9 12 and 1 10 cm2, respectively. The use of PAL permits the heat source to be environmentally separated from the components of the test chamber, simplifying the design to accommodate safe testing of low-level irradiated articles and materials under high-heat flux. Issues related to the operation and temperature measurements during testing of tungsten samples are presented and discussed. The relative advantages and disadvantages of this photon-based HHFT facility are compared to existing e-beam and particle beam facilities used for similar purposes.

Sabau, Adrian S.; Ohriner, Evan K.; Kiggans, Jim; Harper, David C.; Snead, Lance L.; Schaich, Charles R.

2014-04-01

362

Development of a high-throughput cell-based assay for 11beta-hydroxysteroid dehydrogenase type 1 using BacMam technology.  

PubMed

Cortisol is an important glucocorticoid in humans that regulates many physiological processes. Human 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) converts cortisone to cortisol in vivo and has emerged as an appealing therapeutic target for treating metabolic diseases. Here, we report a sensitive and robust high-throughput (HT) cell-based assay for screening 11beta-HSD1 inhibitors. This assay utilizes a HEK293 cell line transduced by a BacMam virus expressing human 11beta-HSD1. The enzyme activity in the cells was measured by quantifying cortisol levels released into the cell culture supernatant via a competitive homogenous time-resolved fluorescence (HTRF) method. We show that 11beta-HSD1 activity in supernatant of BacMam-transduced HEK293 cells increases with 11beta-HSD1 BacMam virus load in a dose-dependent manner, and is comparable to the enzyme activity detected in differentiated mouse adipocytes. In addition, we show that co-expression of hexose-6-phosphate dehydrogenase (H6PDH) is not required for the enzyme to function effectively as an oxo-reductase. This assay has been developed in low-volume 384-well format and it is sensitive, robust, and amenable to HT screening. PMID:18327553

Wang, Da-Yuan; Lu, Quinn; Walsh, Stacey L; Payne, Lisa; Modha, Sundip S; Scott, Martin J; Sweitzer, Thomas D; Ames, Robert S; Krosky, Daniel J; Li, Hu

2008-06-01

363

Ranchin T., Wald L., 2000. Fusion of high spatial and spectral resolution images: the ARSIS concept and its implementation. Photogrammetric Engineering and Remote Sensing, 66(1), 49-61.  

E-print Network

Ranchin T., Wald L., 2000. Fusion of high spatial and spectral resolution images: the ARSIS concept is required in addition with classification results, sensor fusion is a solution. From a set of images presented methods is achieved for a SPOT image. Another example of the fusion of SPOT XS (20 m) and KVR-1000

Paris-Sud XI, Université de

364

Global power balance on high density field reversed configurations for use in magnetized target fusion  

NASA Astrophysics Data System (ADS)

Field Reversed Configuration plasmas (FRCs) have been created in the Field Reversed Experiment-Liner (FRX-L) with density 2--6 x 10 22 m-3, total temperature 300--400 eV, and lifetime on the order of 10 micros. This thesis investigates global energy balance on high-density FRCs for the first time. The zero-dimensional approach to global energy balance developed by Rej and Tuszewski (Phys. Fluids 27, p. 1514, 1984) is utilized here. From the shots analyzed with this method, it is clear that energy loss from these FRCs is dominated by particle and thermal (collisional) losses. The percentage of radiative losses versus total loss is an order of magnitude lower than previous FRC experiments. This is reasonable for high density based on empirical scaling from the extensive database of tokamak plasma experiments. Ohmic dissipation, which heats plasma when trapped magnetic field decays to create electric field, is an important source of heating for the plasma. Ohmic heating shows a correlation with increasing the effective Lundquist number (S*). Empirical evidence suggest S* can be increased by lowering the density, which does not achieve the goals of FRX-L. A better way to improve ohmic heating is to trap more poloidal flux. This dissertation shows that FRX-L follows a semi-empirical scaling law which predicts plasma temperature gains for larger poloidal flux. Flux (tau?) and particle (tauN) lifetimes for these FRCs were typically shorter than 10 micros. Approximately 1/3 of the particle and flux lifetimes for these FRCs did not scale with the usual tauN ? tau? scaling of low-density FRCs, but instead showed tauN ? tau ?. However, scatter in the data indicates that the average performance of FRCs on FRX-L yields the typical (for FRCs) relationship tau N ? tau?. Fusion energy gain Q was extrapolated for the shots analyzed in this study using a zero-dimensional scaling code with liner effects. The predicted Q is below the desired value of 0.1 (Schoenberg et al., LA-UR-98-2413, 1998). The situation predicted to lead to Q = 0.1 requires a larger plasma pressure than shown in the present data. This can be accomplished by increasing the plasma density (through larger fill pressure) and maintaining temperature with increased flux trapping. Larger Q and other benefits could be realized by raising the plasma pressure for future FRX-L shots. The innovation inherent in this work performed by the author is the extension of the global power balance model to include a time history of the plasma discharge. This extension required rigorous checking of the power balance model using internal density profiles provided by the multichord interferometer. Typical orders of the parameters calculated by the model are 500 MW total loss power, 100 MW ohmic heating power, and 200 MW total compression (input) power. Radiation was never measured above 5 MW, which is why it was deemed insignificant. It should be noted that these numbers are merely estimates and vary widely between shots.

Renneke, Richard M.

365

Nuclear fusion  

Microsoft Academic Search

The advantages of nuclear fusion as an energy source and research progress in this area are summarized. The current state of the art is described. Laser fusion, inertial confinement fusion, and magnetic fusion (the tokamak) are explained, the latter in some detail. Remaining problems and planned future reactors are considered. They are the Compact Ignition Tokamak (CIT), the International Thermonuclear

T. K. Fowler

1989-01-01

366

Stable 9 beta- or 11 alpha-halogen-15-cyclohexyl-prostaglandins with high affinity to the PGD2-receptor.  

PubMed

Various chemically stable prostaglandin analogues were studied for their affinity towards the PGD2-receptor in human platelet membranes in order to define the requirements for specific ligand binding to this receptor. On replacing the 11- or 9-hydroxyl groups of PGF2 alpha by an 11 alpha- or 9 beta-chloro- or fluoro atom, stable prostaglandin analogues were obtained, which showed high affinity towards the PGD2-receptor. The lower side chain consisted of a 15-cyclohexyl group or of the natural 15-n-pentyl group, other substitutents decreased the affinity substantially. The highest PGD2-mimetic activity with a relative affinity of 0.5 to the PGD2-receptor was found in 9-deoxy-9 beta-chloro-16,17,18,19,20-pentanor-15-cyclohexyl-PGF2 alpha (ZK 110 841, compound 16 in Table 1). ZK 110 841 is a chemically stable crystalline substance, which is orally active and which might thus turn out to be an interesting tool for the study of PGD2-receptor interactions. Some other prostaglandin as well as prostacyclin analogues with a 15-cyclohexyl or 15-n-pentyl group exhibited in addition to their known high affinity to the PGE2-receptor of human uterine membranes or the PGI2-receptor of human platelets also affinities to the PGD2-receptor. Generally, the receptor affinities correlate with the activities as stimulators of adenylate cyclase and inhibitors of thrombin induced elevation of cytoplasmic free calcium as well as their ability to inhibit ADP-induced platelet aggregation. The PGI2-character regarding the effector systems prevails in compounds with affinity to both the PGI2- and PGD2-receptor. Compounds which bind to the PGE2- and PGD2-receptor show a flat dose response curve regarding platelet activation suggesting a mixture of pro- and antiaggregatory properties within these molecules. PMID:2847246

Thierauch, K H; Strzebecher, C S; Schillinger, E; Rehwinkel, H; Radchel, B; Skuballa, W; Vorbrggen, H

1988-06-01

367

High Beta-Palmitate Fat Controls the Intestinal Inflammatory Response and Limits Intestinal Damage in Mucin Muc2 Deficient Mice  

PubMed Central

Background Palmitic-acid esterified to the sn-1,3 positions of the glycerol backbone (alpha, alpha-palmitate), the predominant palmitate conformation in regular infant formula fat, is poorly absorbed and might cause abdominal discomfort. In contrast, palmitic-acid esterified to the sn-2 position (beta-palmitate), the main palmitate conformation in human milk fat, is well absorbed. The aim of the present study was to examine the influence of high alpha, alpha-palmitate fat (HAPF) diet and high beta-palmitate fat (HBPF) diet on colitis development in Muc2 deficient (Muc2?/?) mice, a well-described animal model for spontaneous enterocolitis due to the lack of a protective mucus layer. Methods Muc2?/? mice received AIN-93G reference diet, HAPF diet or HBPF diet for 5 weeks after weaning. Clinical symptoms, intestinal morphology and inflammation in the distal colon were analyzed. Results Both HBPF diet and AIN-93G diet limited the extent of intestinal erosions and morphological damage in Muc2?/? mice compared with HAPF diet. In addition, the immunosuppressive regulatory T (Treg) cell response as demonstrated by the up-regulation of Foxp3, Tgfb1 and Ebi3 gene expression levels was enhanced by HBPF diet compared with AIN-93G and HAPF diets. HBPF diet also increased the gene expression of Pparg and enzymatic antioxidants (Sod1, Sod3 and Gpx1), genes all reported to be involved in promoting an immunosuppressive Treg cell response and to protect against colitis. Conclusions This study shows for the first time that HBPF diet limits the intestinal mucosal damage and controls the inflammatory response in Muc2?/? mice by inducing an immunosuppressive Treg cell response. PMID:23776564

Lu, Peng; Bar-Yoseph, Fabiana; Levi, Liora; Lifshitz, Yael; Witte-Bouma, Janneke; de Bruijn, Adrianus C. J. M.; Korteland-van Male, Anita M.; van Goudoever, Johannes B.; Renes, Ingrid B.

2013-01-01

368

Beta blockers overdose  

MedlinePLUS

... used to treat high blood pressure. Beta blocker overdose occurs when someone accidentally or intentionally takes more ... is common in children with this type of overdose, and it can lead to nervous system symptoms.

369

Beta experiment  

NASA Technical Reports Server (NTRS)

A focused laser doppler velocimeter (LDV) system was developed for the measurement of atmospheric backscatter (beta) from aerosols at infrared wavelengths. A Doppler signal generator was used in mapping the coherent sensitive focal volume of a focused LDV system. System calibration data was analyzed during the flight test activity scheduled for the Beta system. These analyses were performed to determine the acceptability of the Beta measurement system's performance.

1982-01-01

370

High-Throughput Viral Expression of cDNA-Green Fluorescent Protein Fusions Reveals Novel Subcellular Addresses and Identifies Unique Proteins That Interact with Plasmodesmata  

PubMed Central

A strategy was developed for the high-throughput localization of unknown expressed proteins in Nicotiana benthamiana. Libraries of random, partial cDNAs fused to the 5? or 3? end of the gene for green fluorescent protein (GFP) were expressed in planta using a vector based on Tobacco mosaic virus. Viral populations were screened en masse on inoculated leaves using a confocal microscope fitted with water-dipping lenses. Each viral infection site expressed a unique cDNA-GFP fusion, allowing several hundred cDNA-GFP fusions to be screened in a single day. More than half of the members of the library carrying cDNA fusions to the 5? end of gfp that expressed fluorescent fusion proteins displayed discrete, noncytosolic, subcellular localizations. Nucleotide sequence determination of recovered cDNA sequences and subsequent sequence searches showed that fusions of GFP to proteins that had a predicted subcellular address became localized with high fidelity. In a subsequent screen of >20,000 infection foci, 12 fusion proteins were identified that localized to plasmodesmata, a subcellular structure for which very few protein components have been identified. This virus-based system represents a method for high-throughput functional genomic study of plant cell organelles and allows the identification of unique proteins that associate with specific subcompartments within organelles. PMID:12837943

Escobar, Nieves Medina; Haupt, Sophie; Thow, Graham; Boevink, Petra; Chapman, Sean; Oparka, Karl

2003-01-01

371

Reconstitution of high affinity. cap alpha. /sub 2/ adrenergic agonist binding by fusion with a pertussis toxin substrate  

SciTech Connect

High affinity ..cap alpha../sub 2/ adrenergic agonist binding is thought to occur via a coupling of the ..cap alpha../sub 2/ receptor with N/sub i/, the inhibitory guanyl nucleotide binding protein. Human platelet membranes pretreated at pH 11.5 exhibit a selective inactivation of agonist binding and N/sub i/. To further study the mechanism of agonist binding, alkali treated membranes (ATM) were mixed with membranes pretreated with 10 ..mu..M phenoxybenzamine to block ..cap alpha../sub 2/ receptors (POB-M). The combined membrane pellet was incubated in 50% polyethylene glycol (PEG) to promote membrane-membrane fusion and assayed for binding to the ..cap alpha../sub 2/ agonist (/sup 3/H)UK 14,304 (UK) and the antagonist (/sup 3/H) yohimbine. PEG treatment resulted in a 2-4 fold enhancement of UK binding whereas yohimbine binding was unchanged. No enhancement of UK binding was observed in the absence of PEG treatment. The reconstitution was dependent on the addition of POB-M. They found that a 1:1 ratio of POB-M:ATM was optimal. Reconstituted binding was inhibited by GppNHp. Fusion of rat C6 glioma cell membranes, which do not contain ..cap alpha../sub 2/ receptors, also enhanced agonist binding to ATM. Fusion of C6 membranes from cells treated with pertussis toxin did not enhance (/sup 3/H) UK binding. These data show that a pertussis toxin sensitive membrane component, possibly N/sub i/, can reconstitute high affinity ..cap alpha../sub 2/ agonist binding.

Kim, M.H.; Neubig, R.R.

1986-03-05

372

Fusion Energy Education  

NSDL National Science Digital Library

The basics of fusion are deceptively simple: the process powers the sun and other stars, and it all takes place when atomic nuclei collide at high speed. But many questions remain. How can humans develop and exploit fusion energy? Is there a way to convert it more efficiently into useful mechanical, electrical, or thermal energy? This intriguing site, created by the Lawrence Livermore National Laboratory and the Princeton Plasma Physics Laboratory, presents an online fusion course designed to teach students and others about how fusion works and how it might be harnessed in the future. Visitors can try out The Guided Tour to get started, or they can click on one of the Main Topics. These include Energy Sources and Conversions, Two Key Fusion Reactions, and Creating the Conditions for Fusion. Each section contains graphics, explanatory text, and various diagrams. The site also includes charts which can be printed out for classroom use.

373

Fusion reactor options and alternatives for the Reversed-Field Pinch  

SciTech Connect

One route to improved magnetic fusion power systems places more of the task of plasma confinement on plasma self currents, which, together with high plasma beta, reduce the cost and technology requirements of the surrounding engineering structure. The reversed-field pinch (RFP) is one of these poloidal-field-dominated systems and most recently has been examined as a high-power-density fusion power plant. The compact RFP reactor design has illuminated both advantages and problems associated with this particular (1000 MW(e)(net), 900 kW(e)/tonne, 20 MW/m/sup 2/(neutrons)) resistive coil reactor embodiment. As part of the continuing reassessment of the RFP approach to fusion power, a comprehensive engineering systems model has been used to examine a wide range of RFP physics, engineering, and operational issues that remain less than clear for both RFPs and fusion in general.

Miller, R.L.; Krakowski, R.A.; Hagenson, R.L.

1986-01-01

374

Ultra-high speed photomultiplier tubes with nanosecond gating for fusion diagnostics  

SciTech Connect

Fusion diagnostics can involve the measurement of ultra-fast optical pulses, often in close temporal proximity. We present a solution for the diagnostics of gamma reaction history and neutron time of flight by using microchannel plate based photomultiplier tubes (PMTs). The time response of the PMTs can be as fast as 100 ps FWHM and with a gain of up to 10{sup 7}. To observe small events in close temporal proximity to much larger signals such as the down-scattered fraction, the response of MCP-PMTs can be gated with an on/off ratio of up to 10{sup 13} in just 2 ns.

Milnes, J. S. [Photek Ltd, 26 Castleham Road, St Leonards on Sea, East Sussex, TN38 9NS (United Kingdom); Horsfield, C. J.; Rubery, M. S. [AWE, Aldermaston, Reading, Berkshire, RG7 4PR (United Kingdom); Glebov, V. Yu. [University of Rochester - Laboratory for Laser Energetics, 250 E. River Road, Rochester, New York 14623 (United States); Herrmann, H. W. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2012-10-15

375

Ultra-high speed photomultiplier tubes with nanosecond gating for fusion diagnosticsa)  

NASA Astrophysics Data System (ADS)

Fusion diagnostics can involve the measurement of ultra-fast optical pulses, often in close temporal proximity. We present a solution for the diagnostics of gamma reaction history and neutron time of flight by using microchannel plate based photomultiplier tubes (PMTs). The time response of the PMTs can be as fast as 100 ps FWHM and with a gain of up to 107. To observe small events in close temporal proximity to much larger signals such as the down-scattered fraction, the response of MCP-PMTs can be gated with an on/off ratio of up to 1013 in just 2 ns.

Milnes, J. S.; Horsfield, C. J.; Rubery, M. S.; Glebov, V. Yu.; Herrmann, H. W.

2012-10-01

376

Study of Chelyabinsk LL5 meteorite fragment with a light lithology and its fusion crust using Mssbauer spectroscopy with a high velocity resolution  

NASA Astrophysics Data System (ADS)

Study of Chelyabinsk LL5 ordinary chondrite fragment with a light lithology and its fusion crust, fallen on February 15, 2013, in Russian Federation, was carried out using Mssbauer spectroscopy with a high velocity resolution. The Mssbauer spectra of the internal matter and fusion crust were fitted and all components were related to iron-bearing phases such as olivine, pyroxene, troilite, Fe-Ni-Co alloy, and chromite in the internal matter and olivine, pyroxene, troilite, Fe-Ni-Co alloy, and magnesioferrite in the fusion crust. A comparison of the content of different phases in the internal matter and in the fusion crust of this fragment showed that ferric compounds resulted from olivine, pyroxene, and troilite combustion in the atmosphere.

Maksimova, Alevtina A.; Oshtrakh, Michael I.; Petrova, Evgeniya V.; Grokhovsky, Victor I.; Semionkin, Vladimir A.

2014-10-01

377

The LLNL HFTF (High-Field Test Facility): A flexible superconducting test facility for fusion magnet development  

SciTech Connect

The High-Field Test Facility (HFTF) is a flexible and, in many ways, unique facility at Lawrence Livermore National Laboratory (LLNL) for providing the test capabilities needed to develop the superconducting magnet systems of the next generation fusion machines. The superconducting coil set in HFTF has been operated successfully at LLNL, but in its original configuration, its utility as a test facility was somewhat restricted and cryogenic losses were intolerable. A new cryostat for the coil set allows the magnet system to remain cold indefinitely so the system is available on short notice to provide high fields (about 11 T) inside a reasonably large test volume (0.3-m diam). The test volume is physically and thermally isolated from the coil volume, allowing test articles to be inserted and removed without disturbing the coil cryogenic volume, which is maintained by an on-line refrigerator. Indeed, with the proper precautions, it is even unnecessary to drop the field in the HFTF during such an operation. The separate test volume also allows reduced temperature operation without the expense and complication of subcooling the entire coil set (about 20-t cold mass). The HFTF has thus become a key facility in the LLNL magnet development program, where the primary goal is to demonstrate the technology for producing fields to 15 T with winding-pack current densities of 40 A.mm/sup -2/ in coils sized for fusion applications. 4 refs., 4 figs., 1 tab.

Miller, J.R.; Chaplin, M.R.; Leber, R.L.; Rosdahl, A.R.

1987-09-17

378

Beta-blocker induced changes in the cholesterol: High-density lipoprotein cholesterol ratio and risk of coronary heart disease  

Microsoft Academic Search

Summary The lowering of blood pressure with beta-blocking drugs has had a low impact on coronary heart disease (CHD) mortality and the question has been raised whether adverse changes in plasma lipoproteins offset the benefits of blood pressure reduction. Comparison of plasma lipoprotein concentrations in hypertensive patients treated with commonly used beta-blockers with lipoprotein concentrations in patients with coronary heart

B. G. Woodcock; N. Rietbrock

1984-01-01

379

On the economic prospects of nuclear fusion with tokamaks  

Microsoft Academic Search

A method of cost and construction energy estimation for tokamak fusion power stations conforming to the present stage of fusion development is described. The method is based on first-wall heat load constraints rather than Beta limitations, which, however, might eventually be the more critical of the two. It is used to discuss the economic efficiency of pure fusion, with particular

D. Pfirsch; K. H. Schmitter

1987-01-01

380

Family-wide expression characterization of Arabidopsis beta-carbonic anhydrase genes using qRT-PCR and Promoter::GUS fusions.  

PubMed

Carbonic anhydrases (CAs, EC 4.2.1.1) are metalloenzymes found throughout the phylogenetic tree. The ?-class carbonic anhydrases (?-CAs) are the predominating class of CAs in plants. Growing evidence underscores the importance of ?-CAs in plant immunity and environmental adaptation in addition to their roles in photosynthesis. However, many fundamental problems in Arabidopsis ?CAs expression remain unsolved. Here we examined the transcript abundance of At?CAs in different tissues of Arabidopsis thaliana, and the accumulation of mRNA in response to CO2 and darkness. Histochemical analysis was performed to study the promoter activity of At?CAs during post-germination seedling growth and in mature plants. All six members of the At?CA subfamily showed a response to changed CO2 level and darkness, but each member showed a specific dynamic pattern. Although expression of each At?CA was unique, in general most At?CAs were synchronously expressed in green leaves since 5 days after germination until flowering. At?CA1 and At?CA2 were most highly expressed in leaves but At?CA2 displayed weaker expression in roots. The level of At?CA3 transcripts was highest in flowers, while At?CA5 was most widely expressed and might be involved in more processes than other members. At?CA6 was unique for increased expression in darkness and no expression in either the anther or pistil. The present study provides useful information for further functional investigation. PMID:24211190

Wang, Meng; Zhang, Qiong; Liu, Fang-Chun; Xie, Wei-Fa; Wang, Guang-Dong; Wang, Jun; Gao, Qing-Hua; Duan, Ke

2014-02-01

381

Changes in serum dopamine-beta-hydroxylase activity during cold pressor test in subjects with high and low basal activity of this enzyme  

Microsoft Academic Search

Summary Twenty-seven healthy subjects, eight with high levels, eight with low levels and eleven with intermediate levels of serum dopamine-beta-hydroxylase (DBH) activity, were investigated. Serum DBH activity and blood pressure were measured in their response to the cold pressure test (CPT). Plasma renin activity (PRA) was also estimated.

L. Laurian; Z. Oberman; E. Kisch; A. Fitermann

1982-01-01

382

Highly precise Re-Os dating for molybdenite using alkaline fusion and NTIMS  

USGS Publications Warehouse

The technique described in this paper represents the modification and combination of two previously existing methods, alkaline fusion and negative thermal ion mass spectrometry (NTIMS). We have used this technique to analyze repeatedly a homogeneous molybdenite powder used as a reference standard in our laboratory. Analyses were made over a period of 18 months, using four different calibrations of two different spike solutions. The age of this standard reproduces at a level of ?? 0.13%. Each individual age analysis carries an uncertainty of about 0.4% that includes the uncertainty in the decay constant for 187Re. This new level of resolution has allowed us to recognize real differences in ages for two grain-size populations of molybdenite from some Archean samples.

Markey, R.; Stein, H.; Morgan, J.

1998-01-01

383

Symmetric inertial confinement fusion implosions at ultra-high laser energies  

SciTech Connect

The first indirect-drive hohlraum experiments at the National Ignition Facility have demonstrated symmetric capsule implosions at unprecedented laser drive energies of 0.7 MJ. 192 simultaneously fired laser beams heat ignition hohlraums to radiation temperatures of 3.3 million Kelvin compressing 1.8-millimeter capsules by the soft x rays produced by the hohlraum. Self-generated plasma-optics gratings on either end of the hohlraum tune the laser power distribution in the hohlraum producing symmetric x-ray drive as inferred from capsule self-emission measurements. These experiments indicate conditions suitable for compressing deuterium-tritium filled capsules with the goal to achieve burning fusion plasmas and energy gain in the laboratory.

Glenzer, S H; MacGowan, B J; Michel, P; Meezan, N B; Suter, L J; Dixit, S N; Kline, J L; Kyrala, G A; Callahan, D A; Dewald, E L; Divol, L; Dzenitis, E; Edwards, J; Hamza, A V; Haynam, C A; Hinkel, D E; Kalantar, D H; Kilkenny, J D; Landen, O L; Lindle, J D; LePape, S; Moody, J D; Nikroo, A; Parham, T; Schneider, M B; Town, R J; Wegner, P; Widmann, K; Whitman, P; Young, B F; Van Wonterghem, B; Atherton, J E; Moses, E I

2009-12-03

384

Vacuum insulation of the high energy negative ion source for fusion application  

SciTech Connect

Vacuum insulation on a large size negative ion accelerator with multiple extraction apertures and acceleration grids for fusion application was experimentally examined and designed. In the experiment, vacuum insulation characteristics were investigated in the JT-60 negative ion source with >1000 apertures on the grid with the surface area of {approx}2 m{sup 2}. The sustainable voltages varied with a square root of the gap lengths between the grids, and decreased with number of the apertures and with the surface area of the grids. Based on the obtained results, the JT-60SA (super advanced) negative ion source is designed to produce 22 A, 500 keV D{sup -} ion beams for 100 s.

Kojima, A.; Hanada, M.; Inoue, T.; Watanabe, K.; Taniguchi, M.; Kashiwagi, M.; Umeda, N.; Tobari, H. [Japan Atomic Energy Agency, Naka, Ibaraki 311-0193 (Japan); Hilmi, A.; Kobayashi, S.; Yamano, Y. [Saitama University, Saitama, Saitama-ken, 338-8570 (Japan); Grisham, L. R. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

2012-02-15

385

Vacuum insulation of the high energy negative ion source for fusion application.  

PubMed

Vacuum insulation on a large size negative ion accelerator with multiple extraction apertures and acceleration grids for fusion application was experimentally examined and designed. In the experiment, vacuum insulation characteristics were investigated in the JT-60 negative ion source with >1000 apertures on the grid with the surface area of ?2 m(2). The sustainable voltages varied with a square root of the gap lengths between the grids, and decreased with number of the apertures and with the surface area of the grids. Based on the obtained results, the JT-60SA (super advanced) negative ion source is designed to produce 22 A, 500 keV D(-) ion beams for 100 s. PMID:22380274

Kojima, A; Hanada, M; Hilmi, A; Inoue, T; Watanabe, K; Taniguchi, M; Kashiwagi, M; Umeda, N; Tobari, H; Kobayashi, S; Yamano, Y; Grisham, L R

2012-02-01

386

Application of railgun principle to high-velocity hydrogen pellet injection for magnetic fusion reactor refueling  

SciTech Connect

This report contains three documents describing the progress made by the University of Illinois electromagnetic railgun program sponsored by the Office of Fusion Energy of the United States Department of Energy during the period from July 16, 1990 to August 16, 1991. The first document contains a brief summary of the tasks initiated, continued, or completed, the status of major tasks, and the research effort distribution, estimated and actual, during the period. The second document contains a description of the work performed on time resolved laser interferometric density measurement of the railgun plasma-arc armature. The third document is an account of research on the spectroscopic measurement of the electron density and temperature of the railgun plasma arc.

Kim, K.

1991-08-01

387

High heat flux testing of HIP bonded DS-Cu/316SS first wall panel for fusion experimental reactors  

SciTech Connect

A shielding blanket design in a fusion reactor such as ITER has been proposed to be a modulator structure integrated with the first wall. In terms of the fabrication, HIP (Hot Isostatic Pressing) method has been proposed for the joining of dispersion strengthened copper (DS-Cu) and type 316L stainless steel (SS316L) at FW. High heat flux tests of HIP bonded DS-Cu/SS316L first wall panel were performed at particle Beam Engineering Facility in JAERI to investigate its thermo-mechanical performance. After four campaigns of high heat flux testing, the FW panel was cut to observe the HIP bonded interface and heated surface of DS-Cu. Though melting of DS-Cu surface was observed, there were no cracks at the HIP bonded interface. 2 refs., 11 figs., 1 tab.

Hatano, Toshihisa; Sato, Kazuyoshi; Dairaku, Masayuki [Japan Atomic Energy Research Inst., Ibaraki (Japan)] [and others

1996-12-31

388

Lower hybrid current drive in experiments for transport barriers at high {beta}{sub N} of JET (Joint European Torus)  

SciTech Connect

LHCD has been used in JET experiments aimed at producing internal transport barriers (ITBs) in highly triangular plasmas ({delta}{approx_equal}0.4) at high {beta}{sub N} (up to 3) for steady-state application. The LHCD is a potentially valuable tool for (i) modifying the target q-profile, which can help avoid deleterious MHD modes and favour the formation of ITBs, and (ii) contributing to the non-inductive current drive required to prolong such plasma regimes. The q-profile evolution has been simulated during the current ramp-up phase for such a discharge (B{sub 0} = 2.3 T, I{sub P} = 1.5 MA) where 2 MW of LHCD has been coupled. The JETTO code was used taking measured plasma profiles, and the LHCD profile modeled by the LHstar code. The results are in agreement with MSE measurements and indicate the importance of the elevated electron temperature due to LHCD, as well as the driven current. During main heating with 18 MW of NBI and 3 MW of ICRH the bootstrap current density at the edge also becomes large, consistently with the observed reduction of the local turbulence and of the MHD activity. JETTO modelling suggests that the bootstrap current can reduce the magnetic shear (sh) at large radius, potentially affecting the MHD stability and turbulence behaviour in this region. Keywords: lower hybrid current drive (LHCD), bootstrap current, q (safety factor) and shear (sh) profile evolutions.

Cesario, R. C.; Castaldo, C.; De Angelis, R.; Smeulders, P.; Calabro, G.; Pericoli, V.; Ravera, G. [Associazione EURATOM/ENEA sulla Fusione Frascati (Italy); Fonseca, A. [Associacao EURATOM/IST Centro de Fusao Nuclear, 1049-001 Lisbon (Portugal); Parail, V.; Beurskens, M.; Brix, M.; Vries, P. de; Mailloux, J. [EURATOM/UKAEA Fusion Association, Culha Science Centre, Abingdon, OX14 3DB (United Kingdom); Zagorski, R. [Institute of Plasma Physics and Laser Microfusion, EURATOM Association Warsaw (Poland)

2007-09-28

389

Fusion of Kinect depth data with trifocal disparity estimation for near real-time high quality depth maps generation  

NASA Astrophysics Data System (ADS)

Generating depth maps along with video streams is valuable for Cinema and Television production. Thanks to the improvements of depth acquisition systems, the challenge of fusion between depth sensing and disparity estimation is widely investigated in computer vision. This paper presents a new framework for generating depth maps from a rig made of a professional camera with two satellite cameras and a Kinect device. A new disparity-based calibration method is proposed so that registered Kinect depth samples become perfectly consistent with disparities estimated between rectified views. Also, a new hierarchical fusion approach is proposed for combining on the flow depth sensing and disparity estimation in order to circumvent their respective weaknesses. Depth is determined by minimizing a global energy criterion that takes into account the matching reliability and the consistency with the Kinect input. Thus generated depth maps are relevant both in uniform and textured areas, without holes due to occlusions or structured light shadows. Our GPU implementation reaches 20fps for generating quarter-pel accurate HD720p depth maps along with main view, which is close to real-time performances for video applications. The estimated depth is high quality and suitable for 3D reconstruction or virtual view synthesis.

Boisson, Guillaume; Kerbiriou, Paul; Drazic, Valter; Bureller, Olivier; Sabater, Neus; Schubert, Arno

2014-03-01

390

Pulsed Operation of a Compact Fusion Neutron Source Using a High-Voltage Pulse Generator Developed for Landmine Detection  

SciTech Connect

Preliminary experimental results of pulsed neutron source based on a discharge-type beam fusion called Inertial Electrostatic Confinement Fusion (IECF) for landmine detection are presented. In Japan, a research and development project for constructing an advanced anti-personnel landmine detection system by using IECF, which is effective not only for metal landmines but also for plastic ones, is now in progress. This project consists of some R and D topics, and one of them is R and D of a high-voltage pulse generator system specialized for landmine detection, which can be used in the severe environment such as that in the field in Afghanistan. Thus a prototype of the system for landmine detection was designed and fabricated in consideration of compactness, lightness, cooling performance, dustproof and robustness. By using this prototype pulse generator system, a conventional IECF device was operated as a preliminary experiment. As a result, it was confirmed that the suggested pulse generator system is suitable for landmine detection system, and the results follow the empirical law obtained by the previous experiments. The maximum neutron production rate of 2.0x10{sup 8} n/s was obtained at a pulsed discharge of -51 kV, 7.3 A.

Yamauchi, Kunihito [Tokyo Institute of Technology (Japan); Watanabe, Masato [Tokyo Institute of Technology (Japan); Okino, Akitoshi [Tokyo Institute of Technology (Japan); Kohno, Toshiyuki [Tokyo Institute of Technology (Japan); Hotta, Eiki [Tokyo Institute of Technology (Japan); Yuura, Morimasa [Pulse Electronic Engineering Co., Ltd. (Japan)

2005-05-15

391

New Vectors for Chromosomal Integration Enable High-Level Constitutive or Inducible Magnetosome Expression of Fusion Proteins in Magnetospirillum gryphiswaldense  

PubMed Central

The alphaproteobacterium Magnetospirillum gryphiswaldense biomineralizes magnetosomes, which consist of monocrystalline magnetite cores enveloped by a phospholipid bilayer containing specific proteins. Magnetosomes represent magnetic nanoparticles with unprecedented magnetic and physicochemical characteristics. These make them potentially useful in a number of biotechnological and biomedical applications. Further functionalization can be achieved by expression of foreign proteins via genetic fusion to magnetosome anchor peptides. However, the available genetic tool set for strong and controlled protein expression in magnetotactic bacteria is very limited. Here, we describe versatile vectors for either inducible or high-level constitutive expression of proteins in M. gryphiswaldense. The combination of an engineered native PmamDC promoter with a codon-optimized egfp gene (Mag-egfp) resulted in an 8-fold increase in constitutive expression and in brighter fluorescence. We further demonstrate that the widely used Ptet promoter is functional and tunable in M. gryphiswaldense. Stable and uniform expression of the EGFP and ?-glucuronidase (GusA) reporters was achieved by single-copy chromosomal insertion via Tn5-mediated transposition. In addition, gene duplication by Mag-EGFPEGFP fusions to MamC resulted in further increased magnetosome expression and fluorescence. Between 80 and 210 (for single MamCMag-EGFP) and 200 and 520 (for MamCMag-EGFPEGFP) GFP copies were estimated to be expressed per individual magnetosome particle. PMID:24532068

Borg, Sarah; Hofmann, Julia; Pollithy, Anna; Lang, Claus

2014-01-01

392

Fusion excitation function revisited  

E-print Network

We report on a comprehensive systematics of fusion-evaporation and/or fusion-fission cross sections for a very large variety of systems over an energy range 4-155 A.MeV. Scaled by the reaction cross sections, fusion cross sections do not show a universal behavior valid for all systems although a high degree of correlation is present when data are ordered by the system mass asymmetry.For the rather light and close to mass-symmetric systems the main characteristics of the complete and incomplete fusion excitation functions can be precisely determined. Despite an evident lack of data above 15A.MeV for all heavy systems the available data suggests that geometrical effects could explain the persistence of incomplete fusion at incident energies as high as 155A.MeV.

Ph. Eudes; Z. Basrak; F. Sbille; V. de la Mota; G. Royer; M. Zori?

2012-09-07

393

Accessible passively stored highly spin-polarized D in solid HD, with application to inertially confined fusion  

SciTech Connect

Highly spin-polarized D in solid HD was produced in a dilution refrigerator-magnet system under conditions whereby the polarization remains high upon removal of the sample to a 1K, modest field ([approximately]0.1 T) environment. This retained polarization remains for many hours to days. The first intended application of this system is for inertially confined fusion (ICF) experiments with spin-polarized D fuel. The actual (vector) polarization attained thus far is P[sup D] = 38%. The maximum D polarization obtainable with the present refrigerator and magnet (8 mK and 13 T) is 61%. The difference is due to the author's reluctance to wait the full time constants in these demonstration experiments and due to the inability to attain full efficiency in radio-frequency dynamic polarization transfer between D and H, the maximum polarizability of the latter in the system equaling about 85%. It was necessary to develop methods for cold (4 K) sample transfer with engagement and disengagement provisions for the dilution-refrigerator apparatus, a storage-transport cryostat, various sample-preparation and diagnostic apparatus, and an interface to an experimental destination facility. The nature of the fusion experiments required designing and constructing a complex mating system with interchange of cold shrouds to ascertain the sample was always shielded from room temperature black body radiation, and still provide means for positioning the target to within a few microns of the intersection of the high power laser beams. Means of filling plastic target shells to high pressure with the special isotopic composition of HD with H[sub 2]and D[sub 2] impurities, and condensing them at cryogenic temperatures, were also perfected.

Alexander, N.B.

1992-01-01

394

The Complete Burning of Weapons Grade Plutonium and Highly Enriched Uranium with (Laser Inertial Fusion-Fission Energy) LIFE Engine  

SciTech Connect

The National Ignition Facility (NIF) project, a laser-based Inertial Confinement Fusion (ICF) experiment designed to achieve thermonuclear fusion ignition and burn in the laboratory, is under construction at the Lawrence Livermore National Laboratory (LLNL) and will be completed in April of 2009. Experiments designed to accomplish the NIF's goal will commence in late FY2010 utilizing laser energies of 1 to 1.3 MJ. Fusion yields of the order of 10 to 20 MJ are expected soon thereafter. Laser initiated fusion-fission (LIFE) engines have now been designed to produce nuclear power from natural or depleted uranium without isotopic enrichment, and from spent nuclear fuel from light water reactors without chemical separation into weapons-attractive actinide streams. A point-source of high-energy neutrons produced by laser-generated, thermonuclear fusion within a target is used to achieve ultra-deep burn-up of the fertile or fissile fuel in a sub-critical fission blanket. Fertile fuels including depleted uranium (DU), natural uranium (NatU), spent nuclear fuel (SNF), and thorium (Th) can be used. Fissile fuels such as low-enrichment uranium (LEU), excess weapons plutonium (WG-Pu), and excess highly-enriched uranium (HEU) may be used as well. Based upon preliminary analyses, it is believed that LIFE could help meet worldwide electricity needs in a safe and sustainable manner, while drastically shrinking the nation's and world's stockpile of spent nuclear fuel and excess weapons materials. LIFE takes advantage of the significant advances in laser-based inertial confinement fusion that are taking place at the NIF at LLNL where it is expected that thermonuclear ignition will be achieved in the 2010-2011 timeframe. Starting from as little as 300 to 500 MW of fusion power, a single LIFE engine will be able to generate 2000 to 3000 MWt in steady state for periods of years to decades, depending on the nuclear fuel and engine configuration. Because the fission blanket in a fusion-fission hybrid system is subcritical, a LIFE engine can burn any fertile or fissile nuclear material, including unenriched natural or depleted U and SNF, and can extract a very high percentage of the energy content of its fuel resulting in greatly enhanced energy generation per metric ton of nuclear fuel, as well as nuclear waste forms with vastly reduced concentrations of long-lived actinides. LIFE engines could thus provide the ability to generate vast amounts of electricity while greatly reducing the actinide content of any existing or future nuclear waste and extending the availability of low cost nuclear fuels for several thousand years. LIFE also provides an attractive pathway for burning excess weapons Pu to over 99% FIMA (fission of initial metal atoms) without the need for fabricating or reprocessing mixed oxide fuels (MOX). Because of all of these advantages, LIFE engines offer a pathway toward sustainable and safe nuclear power that significantly mitigates nuclear proliferation concerns and minimizes nuclear waste. An important aspect of a LIFE engine is the fact that there is no need to extract the fission fuel from the fission blanket before it is burned to the desired final level. Except for fuel inspection and maintenance process times, the nuclear fuel is always within the core of the reactor and no weapons-attractive materials are available outside at any point in time. However, an important consideration when discussing proliferation concerns associated with any nuclear fuel cycle is the ease with which reactor fuel can be converted to weapons usable materials, not just when it is extracted as waste, but at any point in the fuel cycle. Although the nuclear fuel remains in the core of the engine until ultra deep actinide burn up is achieved, soon after start up of the engine, once the system breeds up to full power, several tons of fissile material is present in the fission blanket. However, this fissile material is widely dispersed in millions of fuel pebbles, which can be tagged as individual accountable items, and thus made difficult to diver

Farmer, J C; Diaz de la Rubia, T; Moses, E

2008-12-23

395

Ribonuclease S-peptide as a carrier in fusion proteins.  

PubMed Central

S-peptide (residues 1-20) and S-protein (residues 21-124) are the enzymatically inactive products of the limited digestion of ribonuclease A by subtilisin. S-peptide binds S-protein with high affinity to form ribonuclease S, which has full enzymatic activity. Recombinant DNA technology was used to produce a fusion protein having three parts: carrier, spacer, and target. The two carriers used were the first 15 residues of S-peptide (S15) and a mutant S15 in which Asp 14 had been changed to Asn (D14N S15). The spacer consisted of three proline residues and a four-residue sequence recognized by factor Xa protease. The target was beta-galactosidase. The interaction between the S-peptide portion of the fusion protein and immobilized S-protein allowed for affinity purification of the fusion protein under denaturing (S15 as carrier) or nondenaturing (D14N S15 as carrier) conditions. A sensitive method was developed to detect the fusion protein after sodium dodecyl sulfate-polyacrylamide gel electrophoresis by its ribonuclease activity following activation with S-protein. S-peptide has distinct advantages over existing carriers in fusion proteins in that it combines a small size (> or = 15 residues), a tunable affinity for ligand (Kd > or = 10(-9) M), and a high sensitivity of detection (> or = 10(-16) mol in a gel). PMID:8453373

Kim, J. S.; Raines, R. T.

1993-01-01

396

Nuclear fusion  

SciTech Connect

The advantages of nuclear fusion as an energy source and research progress in this area are summarized. The current state of the art is described. Laser fusion, inertial confinement fusion, and magnetic fusion (the tokamak) are explained, the latter in some detail. Remaining problems and planned future reactors are considered. They are the compact ignition tokamak (CIT), the international thermonuclear experimental reactor (ITER), and TIBER II. The design of the latter is shown.

Fowler, T.K. (Dept. of Nuci. Eng., California Univ., Berkeley, CA (US))

1989-05-01

397

Water mobility in the endosperm of high beta-glucan barley mutants as studied by nuclear magnetic resonance imaging.  

PubMed

(1)H NMR imaging (MRI) was used as a noninvasive technique to study water distribution and mobility in hydrated barley (Hordeum vulgare L.) seeds of accessions with varying content of beta glucan (BG), a highly hygroscopic cell wall component. High contents of BG in barley are unfavorable in malting where it leads to clotting of filters and hazing of beer as well as in animal feed where it hinders the rapid uptake of energy. However, a high content of BG has a positive nutritional effect, as it lowers the cholesterol and the glycaemic index. It was studied whether water distribution and mobility were related to content and location of BG. Water mobility was investigated by following the rate and mode of desiccation in hydrated single seeds. In order to determine the different water components, a multispin echo experiment was set up to reveal the T(2) transverse relaxation rates of water within the seeds. A principal component analysis (PCA) discriminated control seeds from the high-BG mutant seeds. MRI proved efficient in tracing the differences in water-holding capacity of contrasting barley seeds. All accessions showed nonuniform distribution of water at full hydration as well as during desiccation. The embryo retained water even after 36 h of drying, whereas the endosperm showed low and heterogeneous mobility of the water after drying. The relaxation time constants indicated that the BG mutants had regions of much higher water mobility around the ventral crease compared to the control. It is concluded that MRI can be applied to investigate temporal and spatial differences in the location of specific chemical compounds in single seeds. PMID:17371735

Fast Seefeldt, Helene; van den Berg, Frans; Kckenberger, Walter; Engelsen, Sren Balling; Wollenweber, Bernd

2007-04-01

398

Spleen tyrosine kinase mediates high glucose-induced transforming growth factor-{beta}1 up-regulation in proximal tubular epithelial cells  

SciTech Connect

The role of spleen tyrosine kinase (Syk) in high glucose-induced intracellular signal transduction has yet to be elucidated. We investigated whether Syk is implicated in high glucose-induced transforming growth factor-{beta}1 (TGF-{beta}1) up-regulation in cultured human proximal tubular epithelial cells (HK-2 cell). High glucose increased TGF-{beta}1 gene expression through Syk, extracellular signal-regulated kinase (ERK), AP-1 and NF-{kappa}B. High glucose-induced AP-1 DNA binding activity was decreased by Syk inhibitors and U0126 (an ERK inhibitor). Syk inhibitors suppressed high glucose-induced ERK activation, whereas U0126 had no effect on Syk activation. High glucose-induced NF-{kappa}B DNA binding activity was also decreased by Syk inhibitors. High glucose increased nuclear translocation of p65 without serine phosphorylation of I{kappa}B{alpha} and without degradation of I{kappa}B{alpha}, but with an increase in tyrosine phosphorylation of I{kappa}B{alpha} that may account for the activation of NF-{kappa}B. Both Syk inhibitors and Syk-siRNA attenuated high glucose-induced I{kappa}B{alpha} tyrosine phosphorylation and p65 nuclear translocation. Depletion of p21-activated kinase 2 (Pak2) by transfection of Pak2-siRNA abolished high glucose-induced Syk activation. In summary, high glucose-induced TGF-{beta}1 gene transcription occurred through Pak2, Syk and subsequent ERK/AP-1 and NF-{kappa}B pathw