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1

Ultra-High Gradient Dielectric Wakefield Accelerator Experiments  

SciTech Connect (OSTI)

Ultra-high gradient dielectric wakefield accelerators are a potential option for a linear collider afterburner since they are immune to the ion collapse and electron/positron asymmetry problems implicit in a plasma based afterburner. The first phase of an experiment to study the performance of dielectric Cerenkov wakefield accelerating structures at extremely high gradients in the GV/m range has been completed. The experiment took advantage of the unique SLAC FFTB electron beam and its ultra-short pulse lengths and high currents (e.g., {sigma}{sub z} = 20 {micro}m at Q = 3 nC). The FFTB electron beam was successfully focused down and sent through short lengths of fused silica capillary tubing (ID = 200 {micro}m/OD = 325 {micro}m). The pulse length of the electron beam was varied to produce a range of electric fields between 2 and 20 GV/m at the inner surface of the dielectric tubes. We observed a sharp increase in optical emissions from the capillaries in the middle part of this surface field range which we believe indicates the transition between sustainable field levels and breakdown. If this initial interpretation is correct, the surfaced fields that were sustained equate to on axis accelerating field of several GV/m. In future experiments being developed for the SLAC SABER and BNL ATF we plan to use the coherent Cerenkov radiation emitted from the capillary tube as a field strength diagnostic and demonstrate GV/m range particle energy gain.

Thompson, M C; Badakov, H; Rosenzweig, J B; Travish, G; Hogan, M; Ischebeck, R; Kirby, N; Siemann, R; Walz, D; Muggli, P; Scott, A; Yoder, R

2006-08-04T23:59:59.000Z

2

Ultra-High Gradient Dielectric Wakefield Accelerator Experiments  

SciTech Connect (OSTI)

Ultra-high gradient dielectric wakefield accelerators are a potential option for a linear collider afterburner since they are immune to the ion collapse and electron/positron asymmetry problems implicit in a plasma based afterburner. The first phase of an experiment to study the performance of dielectric Cerenkov wakefield accelerating structures at extremely high gradients in the GV/m range has been completed. The experiment took advantage of the unique SLAC FFTB electron beam and its ultra-short pulse lengths and high currents (e.g., {sigma}z = 20 {mu}m at Q = 3 nC). The FFTB electron beam was successfully focused down and sent through short lengths of fused silica capillary tubing (ID = 200 {mu}m / OD = 325 {mu}m). The pulse length of the electron beam was varied to produce a range of electric fields between 2 and 20 GV/m at the inner surface of the dielectric tubes. We observed a sharp increase in optical emissions from the capillaries in the middle part of this surface field range which we believe indicates the transition between sustainable field levels and breakdown. If this initial interpretation is correct, the surfaced fields that were sustained equate to on axis accelerating field of several GV/m. In future experiments being developed for the SLAC SABER and BNL ATF we plan to use the coherent Cerenkov radiation emitted from the capillary tube as a field strength diagnostic and demonstrate GV/m range particle energy gain.

Thompson, M. C. [Lawrence Livermore National Laboratory, Livermore, California, 90095 (United States); Badakov, H.; Rosenzweig, J. B.; Travis, G. [UCLA Department of Physics and Astronomy, Los Angeles, California, 90095 (United States); Hogan, M.; Ischebeck, R.; Kirby, N.; Siemann, R.; Walz, D. [Stanford Linear Accelerator Center, Stanford, California, 94309 (United States); Muggli, P. [University of Southern California Los Angeles, California, 90089 (United States); Scott, A. [UCSB Department of Physics, Santa Barbara, California, 93106 (United States); Yoder, R. [Manhattan College, Riverdale, New York, 10471 (United States)

2006-11-27T23:59:59.000Z

3

Preliminary Results from the UCLA/SLAC Ultra-High Gradient CerenkovWakefield Accelerator Experiment  

SciTech Connect (OSTI)

The first phase of an experiment to study the performance of dielectric Cerenkov wakefield accelerating structures at extremely high gradients in the GV/m range has been completed. This experiment takes advantage of the unique SLAC FFTB electron beam and its demonstrated ultra-short pulse lengths and high currents (e.g., {sigma}{sub z} = 20 {micro}m at Q = 3 nC). The FFTB electron beam has been successfully focused down and sent through varying lengths of fused silica capillary tubing with two different sizes: ID = 200 {micro}m/OD = 325 {micro}m and ID = 100 {micro}m/OD = 325 {micro}m. The pulse length of the electron beam was varied in the range 20 {micro}m < {sigma}{sub z} < 100 {micro}m which produced a range of electric fields between 2 and 20 GV/m at the inner surface of the dielectric tubes. We observed a sharp increase in optical emissions from the capillaries in the middle part of this surface field range which we believe indicates the transition between sustainable field levels and breakdown. If this initial interpretation is correct, the surfaced fields that were sustained equate to on axis accelerating field of several GV/m. In future experiments we plan to collect and measure coherent Cerenkov radiation emitted from the capillary tube to gain more information about the strength of the accelerating fields.

Thompson, M.C.; Badakov, H.; Rosenzweig, J.B.; Travish, G.; /UCLA; Hogan, M.; Ischebeck, R.; Kirby, N.; Siemann, R.; Walz, D.; /SLAC; Muggli, P.; /Southern California U.; Scott, A.; /UC, Santa Barbara; Yoder, R.; /Manhattan Coll., Riverdale

2008-02-06T23:59:59.000Z

4

Development of high gradient laser wakefield accelerators towards nuclear detection applications at LBNL  

E-Print Network [OSTI]

laser wakefield accelerators towards nuclear detectionRecent laser wakefield accelerator experiments at LBNLscaling of laser driven accelerators to GeV energies. Stable

Geddes, Cameron GR

2010-01-01T23:59:59.000Z

5

Control of seeding phase for a cascaded laser wakefield accelerator with gradient injection  

SciTech Connect (OSTI)

We demonstrated experimentally the seeding-phase control for a two-stage laser wakefield accelerator with gradient injection. By optimizing the seeding phase of electrons into the second stage, electron beams beyond 0.5 GeV with a 3% rms energy spread were produced over a short acceleration distance of ?2 mm. Peak energy of the electron beam was further extended beyond 1 GeV by lengthening the second acceleration stage to 5 mm. Time-resolved magnetic field measurements via magneto-optical Faraday polarimetry allowed us to monitor the processes of electron seeding and acceleration in the second stage.

Wang, Wentao; Li, Wentao; Liu, Jiansheng; Wang, Cheng; Chen, Qiang; Zhang, Zhijun; Qi, Rong; Leng, Yuxin; Liang, Xiaoyan; Liu, Yanqi; Lu, Xiaoming; Wang, Cheng; Li, Ruxin; Xu, Zhizhan [State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences (CAS), Shanghai 201800 (China)] [State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences (CAS), Shanghai 201800 (China)

2013-12-09T23:59:59.000Z

6

High field gradient particle accelerator  

DOE Patents [OSTI]

A high electric field gradient electron accelerator utilizing short duration, microwave radiation, and capable of operating at high field gradients for high energy physics applications or at reduced electric field gradients for high average current intermediate energy accelerator applications is disclosed. Particles are accelerated in a smooth bore, periodic undulating waveguide, wherein the period is so selected that the particles slip an integral number of cycles of the r.f. wave every period of the structure. This phase step of the particles produces substantially continuous acceleration in a traveling wave without transverse magnetic or other guide means for the particle. 10 figs.

Nation, J.A.; Greenwald, S.

1989-05-30T23:59:59.000Z

7

High field gradient particle accelerator  

DOE Patents [OSTI]

A high electric field gradient electron accelerator utilizing short duration, microwave radiation, and capable of operating at high field gradients for high energy physics applications or at reduced electric field gradients for high average current intermediate energy accelerator applications. Particles are accelerated in a smooth bore, periodic undulating waveguide, wherein the period is so selected that the particles slip an integral number of cycles of the r.f. wave every period of the structure. This phase step of the particles produces substantially continuous acceleration in a traveling wave without transverse magnetic or other guide means for the particle.

Nation, John A. (Ithaca, NY); Greenwald, Shlomo (Haifa, IL)

1989-01-01T23:59:59.000Z

8

The Extended Finite Element Method for High Gradient Solutions  

E-Print Network [OSTI]

Outline Enrichment functions for high gradient solutions Motivation High gradient inside the domain (Shocks) High gradient at the boundary (boundary layers) Optimal set of enrichment functions Numerical for high gradient solutions Outline Enrichment functions for high gradient solutions Motivation High

9

Modeling Laser Wakefield Accelerators in a Lorentz Boosted Frame  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Modeling Laser Modeling Laser Wakefield Accelerators in a Lorentz Boosted Frame Modeling Laser Wakefield Accelerators in a Lorentz Boosted Frame VayBoost.gif An image showing the "boosted frame," in which the observer moves at near light speed. The laser pulse is represented in blue and red; the wakefields are colored pale blue and yellow. In this frame, the plasma (yellow box) has contracted and the wavefronts are fewer and farther apart, resulting in far fewer calculations and faster results. Why it Matters: Laser driven plasma waves can produce accelerating gradients orders of magnitude greater than standard accelerating structures. High quality electron beams of energy up to 1 GeV have been produced in just a few centimeters and 10-GeV stages being planned as

10

Measurement of the Decelerating Wake in a Plasma Wakefield Accelerator  

SciTech Connect (OSTI)

Recent experiments at SLAC have shown that high gradient acceleration of electrons is achievable in meter scale plasmas. Results from these experiments show that the wakefield is sensitive to parameters in the electron beam which drives it. In the experiment the bunch lengths were varied systematically at constant charge. The effort to extract a measurement of the decelerating wake from the maximum energy loss of the electron beam is discussed.

Blumenfeld, I.; Decker, F. J.; Hogan, M. J.; Ischebeck, R.; Iverson, R. H.; Kirby, N.; Siemann, R. H.; Walz, D. R. [Stanford Linear Accelerator Center, Stanford University, Stanford, California 94305 (United States); Clayton, C. E.; Huang, C.; Joshi, C.; Lu, W.; Marsh, K. A.; Mori, W. B.; Zhou, M. [University of California, Los Angeles, California 90095 (United States); Katsouleas, T.; Muggli, P.; Oz, E. [University of Southern California, Los Angeles, California 90089 (United States)

2009-01-22T23:59:59.000Z

11

Mesurement of the Decelerating Wake in a Plasma Wakefield Accelerator  

SciTech Connect (OSTI)

Recent experiments at SLAC have shown that high gradient acceleration of electrons is achievable in meter scale plasmas. Results from these experiments show that the wakefield is sensitive to parameters in the electron beam which drives it. In the experiment the bunch lengths were varied systematically at constant charge. The effort to extract a measurement of the decelerating wake from the maximum energy loss of the electron beam is discussed.

Blumenfeld, I; Clayton, C.E.; Decker, F.J.; Hogan, M.J.; Huang, C.; Ischebeck, R.; Iverson, R.H.; Joshi, C.; Katsouleas, T.; Kirby, N.; Lu, W.; Marsh, K.A.; Mori, W.B.; Muggli, P; Oz, E.; Siemann, R.H.; Walz, D.R.; Zhou, M.; /SLAC /UCLA /USC

2008-09-24T23:59:59.000Z

12

Results from Plasma Wakefield Experiments at FACET  

SciTech Connect (OSTI)

We report initial results of the Plasma Wakefield Acceleration (PWFA) Experiments performed at FACET - Facility for Advanced aCcelertor Experimental Tests at SLAC National Accelerator Laboratory. At FACET a 23 GeV electron beam with 1.8 x 10{sup 10} electrons is compressed to 20 {mu}m longitudinally and focused down to 10 {mu}m x 10 {mu}m transverse spot size for user driven experiments. Construction of the FACET facility completed in May 2011 with a first run of user assisted commissioning throughout the summer. The first PWFA experiments will use single electron bunches combined with a high density lithium plasma to produce accelerating gradients > 10 GeV/m benchmarking the FACET beam and the newly installed experimental hardware. Future plans for further study of plasma wakefield acceleration will be reviewed. The experimental hardware and operation of the plasma heat-pipe oven have been successfully commissioned. Plasma wakefield acceleration was not observed because the electron bunch density was insufficient to ionize the lithium vapor. The remaining commissioning time in summer 2011 will be dedicated to delivering the FACET design parameters for the experimental programs which will begin in early 2012. PWFA experiments require the shorter bunches and smaller transverse sizes to create the plasma and drive large amplitude wakefields. Low emittance and high energy will minimize head erosion which was found to be a limiting factor in acceleration distance and energy gain. We will run the PWFA experiments with the design single bunch conditions in early 2012. Future PWFA experiments at FACET are discussed in [5][6] and include drive and witness bunch production for high energy beam manipulation, ramped bunch to optimize tranformer ratio, field-ionized cesium plasma, preionized plasmas, positron acceleration, etc.. We will install a notch collimator for two-bunch operation as well as new beam diagnostics such as the X-band TCAV [7] to resolve the two bunches. With these new instruments and desired beam parameters in place next year, we will be able to complete the studies of plasma wakefield acceleration in the next few years.

Li, S.Z.; Clarke, C.I.; England, R.J.; Frederico, J.; Gessner, S.J.; Hogan, M.J.; Jobe, R.K.; Litos, M.D.; Walz, D.R.; /SLAC; Muggli, P.; /Munich, Max Planck Inst.; An, W.; Clayton, C.E.; Joshi, C.; Lu, W.; Marsh, K.A.; Mori, W.; Tochitsky, S.; /UCLA; Adli, E.; /U. Oslo

2011-12-13T23:59:59.000Z

13

High-pressure liquid chromatographic gradient mixer  

DOE Patents [OSTI]

A gradient mixer effects the continuous mixing of any two miscible solvents without excessive decay or dispersion of the resultant isocratic effluent or of a linear or exponential gradient. The two solvents are fed under low or high pressure by means of two high performance liquid chromatographic pumps. The mixer comprises a series of ultra-low dead volume stainless steel tubes and low dead volume chambers. The two solvent streams impinge head-on at high fluxes. This initial nonhomogeneous mixture is then passed through a chamber packed with spirally-wound wires which cause turbulent mixing thereby homogenizing the mixture with minimum band-broadening.

Daughton, C.G.; Sakaji, R.H.

1982-09-08T23:59:59.000Z

14

Dielectric Wakefield Accelerator to drive the future FEL Light Source.  

SciTech Connect (OSTI)

X-ray free-electron lasers (FELs) are expensive instruments and a large part of the cost of the entire facility is driven by the accelerator. Using a high-energy gain dielectric wake-field accelerator (DWA) instead of the conventional accelerator may provide a significant cost saving and reduction of the facility size. In this article, we investigate using a collinear dielectric wakefield accelerator to provide a high repetition rate, high current, high energy beam to drive a future FEL x-ray light source. As an initial case study, a {approx}100 MV/m loaded gradient, 850 GHz quartz dielectric based 2-stage, wakefield accelerator is proposed to generate a main electron beam of 8 GeV, 50 pC/bunch, {approx}1.2 kA of peak current, 10 x 10 kHz (10 beamlines) in just 100 meters with the fill factor and beam loading considered. This scheme provides 10 parallel main beams with one 100 kHz drive beam. A drive-to-main beam efficiency {approx}38.5% can be achieved with an advanced transformer ratio enhancement technique. rf power dissipation in the structure is only 5 W/cm{sup 2} in the high repetition rate, high gradient operation mode, which is in the range of advanced water cooling capability. Details of study presented in the article include the overall layout, the transform ratio enhancement scheme used to increase the drive to main beam efficiency, main wakefield linac design, cooling of the structure, etc.

Jing, C.; Power, J.; Zholents, A. (Accelerator Systems Division (APS)); ( HEP); (LLC)

2011-04-20T23:59:59.000Z

15

Plasma wakefields driven by an incoherent combination of laser pulses: a path towards high-average power laser-plasma accelerators  

SciTech Connect (OSTI)

he wakefield generated in a plasma by incoherently combining a large number of low energy laser pulses (i.e.,without constraining the pulse phases) is studied analytically and by means of fully-self-consistent particle-in-cell simulations. The structure of the wakefield has been characterized and its amplitude compared with the amplitude of the wake generated by a single (coherent) laser pulse. We show that, in spite of the incoherent nature of the wakefield within the volume occupied by the laser pulses, behind this region the structure of the wakefield can be regular with an amplitude comparable or equal to that obtained from a single pulse with the same energy. Wake generation requires that the incoherent structure in the laser energy density produced by the combined pulses exists on a time scale short compared to the plasma period. Incoherent combination of multiple laser pulses may enable a technologically simpler path to high-repetition rate, high-average power laser-plasma accelerators and associated applications.

Benedetti, C.; Schroeder, C.B.; Esarey, E.; Leemans, W.P.

2014-05-01T23:59:59.000Z

16

High gradient lens for charged particle beam  

DOE Patents [OSTI]

Methods and devices enable shaping of a charged particle beam. A dynamically adjustable electric lens includes a series of alternating a series of alternating layers of insulators and conductors with a hollow center. The series of alternating layers when stacked together form a high gradient insulator (HGI) tube to allow propagation of the charged particle beam through the hollow center of the HGI tube. A plurality of transmission lines are connected to a plurality of sections of the HGI tube, and one or more voltage sources are provided to supply an adjustable voltage value to each transmission line of the plurality of transmission lines. By changing the voltage values supplied to each section of the HGI tube, any desired electric field can be established across the HGI tube. This way various functionalities including focusing, defocusing, acceleration, deceleration, intensity modulation and others can be effectuated on a time varying basis.

Chen, Yu-Jiuan

2014-04-29T23:59:59.000Z

17

Laser Wakefield Particle Accelerators Project at NERSC  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Laser Wakefield Particle Acceleration Laser Wakefield Particle Acceleration Vorpal.jpg Key Challenges: Design of multiple-staged, 10-GeV laser-wakefield plasma accelerated...

18

High-gradient compact linear accelerator  

DOE Patents [OSTI]

A high-gradient linear accelerator comprises a solid-state stack in a vacuum of five sets of disc-shaped Blumlein modules each having a center hole through which particles are sequentially accelerated. Each Blumlein module is a sandwich of two outer conductive plates that bracket an inner conductive plate positioned between two dielectric plates with different thicknesses and dielectric constants. A third dielectric core in the shape of a hollow cylinder forms a casing down the series of center holes, and it has a dielectric constant different that the two dielectric plates that sandwich the inner conductive plate. In operation, all the inner conductive plates are charged to the same DC potential relative to the outer conductive plates. Next, all the inner conductive plates are simultaneously shorted to the outer conductive plates at the outer diameters. The signal short will propagate to the inner diameters at two different rates in each Blumlein module. A faster wave propagates quicker to the third dielectric core across the dielectric plates with the closer spacing and lower dielectric constant. When the faster wave reaches the inner extents of the outer and inner conductive plates, it reflects back outward and reverses the field in that segment of the dielectric core. All the field segments in the dielectric core are then in unipolar agreement until the slower wave finally propagates to the third dielectric core across the dielectric plates with the wider spacing and higher dielectric constant. During such unipolar agreement, particles in the core are accelerated with gradients that exceed twenty megavolts per meter.

Carder, Bruce M. (205 Rogue River Hwy., Gold Hill, OR 97525)

1998-01-01T23:59:59.000Z

19

High-gradient compact linear accelerator  

DOE Patents [OSTI]

A high-gradient linear accelerator comprises a solid-state stack in a vacuum of five sets of disc-shaped Blumlein modules each having a center hole through which particles are sequentially accelerated. Each Blumlein module is a sandwich of two outer conductive plates that bracket an inner conductive plate positioned between two dielectric plates with different thicknesses and dielectric constants. A third dielectric core in the shape of a hollow cylinder forms a casing down the series of center holes, and it has a dielectric constant different that the two dielectric plates that sandwich the inner conductive plate. In operation, all the inner conductive plates are charged to the same DC potential relative to the outer conductive plates. Next, all the inner conductive plates are simultaneously shorted to the outer conductive plates at the outer diameters. The signal short will propagate to the inner diameters at two different rates in each Blumlein module. A faster wave propagates quicker to the third dielectric core across the dielectric plates with the closer spacing and lower dielectric constant. When the faster wave reaches the inner extents of the outer and inner conductive plates, it reflects back outward and reverses the field in that segment of the dielectric core. All the field segments in the dielectric core are then in unipolar agreement until the slower wave finally propagates to the third dielectric core across the dielectric plates with the wider spacing and higher dielectric constant. During such unipolar agreement, particles in the core are accelerated with gradients that exceed twenty megavolts per meter. 10 figs.

Carder, B.M.

1998-05-26T23:59:59.000Z

20

Proton-driven plasma wakefield acceleration: a path to the future of high-energy particle physics  

E-Print Network [OSTI]

New acceleration technology is mandatory for the future elucidation of fundamental particles and their interactions. A promising approach is to exploit the properties of plasmas. Past research has focused on creating large-amplitude plasma waves by injecting an intense laser pulse or an electron bunch into the plasma. However, the maximum energy gain of electrons accelerated in a single plasma stage is limited by the energy of the driver. Proton bunches are the most promising drivers of wakefields to accelerate electrons to the TeV energy scale in a single stage. An experimental program at CERN -- the AWAKE experiment -- has been launched to study in detail the important physical processes and to demonstrate the power of proton-driven plasma wakefield acceleration. Here we review the physical principles and some experimental considerations for a future proton-driven plasma wakefield accelerator.

Assmann, R; Bohl, T; Bracco, C; Buttenschon, B; Butterworth, A; Caldwell, A; Chattopadhyay, S; Cipiccia, S; Feldbaumer, E; Fonseca, R A; Goddard, B; Gross, M; Grulke, O; Gschwendtner, E; Holloway, J; Huang, C; Jaroszynski, D; Jolly, S; Kempkes, P; Lopes, N; Lotov, K; Machacek, J; Mandry, S R; McKenzie, J W; Meddahi, M; Militsyn, B L; Moschuering, N; Muggli, P; Najmudin, Z; Noakes, T C Q; Norreys, P A; Oz, E; Pardons, A; Petrenko, A; Pukhov, A; Rieger, K; Reimann, O; Ruhl, H; Shaposhnikova, E; Silva, L O; Sosedkin, A; Tarkeshian, R; Trines, R M G N; Tuckmantel, T; Vieira, J; Vincke, H; Wing, M; Xia, G

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high gradient wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

High-repetition Rate Wakefield Electron Source Driven by Few-millijoule Ultrashort Laser Pulses  

Science Journals Connector (OSTI)

10 mJ ultrafast laser pulses acting on gas flow from capillary nozzles generate stable 100 keV electron beams at 500 Hz. Particle-in-cell simulations indicate that slow high amplitude...

He, Zhaohan; Hou, Bixue; Easter, James; Krushelnick, Karl; Nees, John A; Thomas, Alexander

22

Computational studies and optimization of wakefield accelerators  

E-Print Network [OSTI]

optimization of wakefield accelerators C. G. R. Geddes 1 ,from the U.S. -LHC Accelerator Research Program (LARP),driven plasma wakefield accelerators produce accelerating

Geddes, C.G.R.

2010-01-01T23:59:59.000Z

23

Plasma wakefields driven by an incoherent combination of laser pulses: a path towards high-average power laser-plasma accelerators  

E-Print Network [OSTI]

and W.P. Leemans, Phys. Plasmas 18, 083103 (2011). 34 C.IEEE Transactions on plasma science 36, 1790 (2008). 35 C.Plasma wakefields driven by an incoherent combination of

Benedetti, C

2014-01-01T23:59:59.000Z

24

High-power radio frequency pulse generation and extration based on wakefield excited by an intense charged particle beam in dielectric-loaded waveguides.  

SciTech Connect (OSTI)

Power extraction using a dielectric-loaded (DL) waveguide is a way to generate high-power radio frequency (RF) waves for future particle accelerators, especially for two-beam-acceleration. In a two-beam-acceleration scheme, a low-energy, high-current particle beam is passed through a deceleration section of waveguide (decelerator), where the power from the beam is partially transferred to trailing electromagnetic waves (wakefields); then with a properly designed RF output coupler, the power generated in the decelerator is extracted to an output waveguide, where finally the power can be transmitted and used to accelerate another usually high-energy low-current beam. The decelerator, together with the RF output coupler, is called a power extractor. At Argonne Wakefield Accelerator (AWA), we designed a 7.8GHz power extractor with a circular DL waveguide and tested it with single electron bunches and bunch trains. The output RF frequency (7.8GHz) is the sixth harmonic of the operational frequency (1.3GHz) of the electron gun and the linac at AWA. In single bunch excitation, a 1.7ns RF pulse with 30MW of power was generated by a single 66nC electron bunch passing through the decelerator. In subsequent experiments, by employing different splitting-recombining optics for the photoinjector laser, electron bunch trains were generated and thus longer RF pulses could be successfully generated and extracted. In 16-bunch experiments, 10ns and 22ns RF pulses have been generated and extracted; and in 4-bunch experiments, the maximum power generated was 44MW with 40MW extracted. A 26GHz DL power extractor has also been designed to test this technique in the millimeter-wave range. A power level of 148MW is expected to be generated by a bunch train with a bunch spacing of 769ps and bunch charges of 20nC each. The arrangement for the experiment is illustrated in a diagram. Higher-order-mode (HOM) power extraction has also been explored in a dual-frequency design. By using a bunch train with a bunch spacing of 769ps and bunch charges of 50nC each, 90.4MW and 8.68MW of extracted power levels are expected to be reached at 20.8GHz and 35.1GHz, respectively. In order to improve efficiency in HOM power extraction, a novel technique has been proposed to suppress unintended modes.

Gao, F.; High Energy Physics; Illinois Inst. of Tech

2009-07-24T23:59:59.000Z

25

High and ulta-high gradient quadrupole magnets  

SciTech Connect (OSTI)

Small bore conventional dc quadrupoles with apertures from 1 to 2.578cm were designed and prototypes built and measured. New fabrication techniques including the use of wire electric discharge milling (EDM) to economically generate the pole tip contours and aperture tolerances are described. Magnetic measurement data from a prototype of a 1cm aperture quadrupole with possible use in future e/sup +//e/sup -/ super colliders are presented. At a current of 400A, the lens achieved a gradient of 2.475 T/cm, and had an efficiency of 76.6%.

Brunk, W.O.; Walz, D.R.

1985-05-01T23:59:59.000Z

26

Fabrication of high gradient insulators by stack compression  

DOE Patents [OSTI]

Individual layers of a high gradient insulator (HGI) are first pre-cut to their final dimensions. The pre-cut layers are then stacked to form an assembly that is subsequently pressed into an HGI unit with the desired dimension. The individual layers are stacked, and alignment is maintained, using a sacrificial alignment tube that is removed after the stack is hot pressed. The HGI's are used as high voltage vacuum insulators in energy storage and transmission structures or devices, e.g. in particle accelerators and pulsed power systems.

Harris, John Richardson; Sanders, Dave; Hawkins, Steven Anthony; Norona, Marcelo

2014-04-29T23:59:59.000Z

27

Dielectric-Lined High-Gradient Accelerator Structure  

SciTech Connect (OSTI)

Rectangular particle accelerator structures with internal planar dielectric elements have been studied, with a view towards devising structures with lower surface fields for a given accelerating field, as compared with structures without dielectrics. Success with this concept is expected to allow operation at higher accelerating gradients than otherwise on account of reduced breakdown probabilities. The project involves studies of RF breakdown on amorphous dielectrics in test cavities that could enable high-gradient structures to be built for a future multi-TeV collider. The aim is to determine what the limits are for RF fields at the surfaces of selected dielectrics, and the resulting acceleration gradient that could be achieved in a working structure. The dielectric of principal interest in this study is artificial CVD diamond, on account of its advertised high breakdown field ({approx}2 GV/m for dc), low loss tangent, and high thermal conductivity. Experimental studies at mm-wavelengths on materials and structures for achieving high acceleration gradient were based on the availability of the 34.3 GHz third-harmonic magnicon amplifier developed by Omega-P, and installed at the Yale University Beam Physics Laboratory. Peak power from the magnicon was measured to be about 20 MW in 0.5 {micro}s pulses, with a gain of 54 dB. Experiments for studying RF high-field effects on CVD diamond samples failed to show any evidence after more than 10{sup 5} RF pulses of RF breakdown up to a tangential surface field strength of 153 MV/m; studies at higher fields were not possible due to a degradation in magnicon performance. A rebuild of the tube is underway at this writing. Computed performance for a dielectric-loaded rectangular accelerator structure (DLA) shows highly competitive properties, as compared with an existing all-metal structure. For example, comparisons were made of a DLA structure having two planar CVD diamond elements with a all-metal CERN structure HDS operating at 30 GHz. It was shown that the ratio of maximum surface electric field to accelerating field at the metal wall is only 0.35-0.4 for DLA, much smaller than the value 2.2 for HDS; and the ratio of surface magnetic field to accelerating field is 3.0 mA/V for DLA, compared with 3.45 mA/V for HDS. These values bode well for DLA in helping to avoid breakdown and to reducing pulsed surface heating and fatigue. The shunt impedance is found to be 160-175 M{Omega}/m for DLA, as compared to 99 M{Omega}/m for HDS. Conclusions are reached from this project that CVD diamond appears promising as a dielectric with a high threshold for RF breakdown, and that rectangular accelerator structures can be devised using planar CVD diamond elements that could be operated at higher acceleration gradients with low probability of RF breakdown, as compared with corresponding all-metallic structures.

Jay L. Hirshfield

2012-04-24T23:59:59.000Z

28

Plasma Wakefield Acceleration  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

rpwa rpwa Sign In Launch the Developer Dashboard SLAC National Accelerator Laboratory DOE | Stanford | SLAC | SSRL | LCLS | AD | PPA | Photon Science | PULSE | SIMES FACET User Facility : FACET An Office of Science User Facility Search this site... Search Help (new window) Top Link Bar FACET User Facility FACET Home About FACET FACET Experimental Facilities FACET Users Research at FACET SAREC Expand SAREC FACET FAQs FACET User Facility Quick Launch FACET Users Home FACET Division ARD Home About FACET FACET News FACET Users FACET Experimental Facilities FACET Research Expand FACET Research FACET Images Expand FACET Images SAREC Expand SAREC FACET Project Site (restricted) FACET FAQs FACET Site TOC All Site Content Department of Energy Page Content Plasma Wakefield Acceleration

29

High-Performance Ionic Diode Membrane for Salinity Gradient Power Generation  

Science Journals Connector (OSTI)

High-Performance Ionic Diode Membrane for Salinity Gradient Power Generation ... These processes can also capture energy from waste heat by generating artificial salinity gradients using synthetic solns., such as thermolytic salts. ... saline brines because of the higher power d. ...

Jun Gao; Wei Guo; Dan Feng; Huanting Wang; Dongyuan Zhao; Lei Jiang

2014-08-19T23:59:59.000Z

30

Dielectric-Loaded Microwave Cavity for High-Gradient Testing of Superconducting Materials  

E-Print Network [OSTI]

an energy distribution. Data was taken from the CRC Handbook 90th edition [13]. : : : : : : : : : : : : : : : : : : : : 17 10 Current state of high gradient cavities in the SRF world. Note these points are champion cavities, the average gradient of all... an energy distribution. Data was taken from the CRC Handbook 90th edition [13]. : : : : : : : : : : : : : : : : : : : : 17 10 Current state of high gradient cavities in the SRF world. Note these points are champion cavities, the average gradient of all...

Pogue, Nathaniel Johnston

2011-08-08T23:59:59.000Z

31

Modified Magnicon for High-Gradient Accelerator R&D  

SciTech Connect (OSTI)

Analysis, and low-power cold tests are described on a modified design intended for the Ka-band pulsed magnicon now in use for high-gradient accelerator R and D and rare elementary particle searches at the Yale University Beam Physics Laboratory. The modification is mainly to the output cavity of the magnicon, which presently operates in the TM310 mode. It is proposed to substitute for this a dual-chamber TE311 cavity structure. The first chamber is to extract about 40% of the beam power (about 25 MW) at 34.272 GHz, while the second chamber is to convey the power to four WR-28 output waveguides. Minor design changes are also proposed for the penultimate 11.424 GHz cavity and the beam collector. The intention of these design changes is to allow the magnicon to operate reliably 24/7, with minor sensitivity to operating parameters.

Jay L. Hirshfield

2011-12-19T23:59:59.000Z

32

Generation of wakefields by whistlers in spin quantum magnetoplasmas  

SciTech Connect (OSTI)

The excitation of electrostatic wakefields in a magnetized spin quantum plasma by the classical and the spin-induced ponderomotive force (CPF and SPF, respectively) due to whistler waves is reported. The nonlinear dynamics of the whistlers and the wakefields is shown to be governed by a coupled set of nonlinear Schroedinger and driven Boussinesq-like equations. It is found that the quantum force associated with the Bohm potential introduces two characteristic length scales, which lead to the excitation of multiple wakefields in a strongly magnetized dense plasma (with a typical magnetic field strength B{sub 0} or approx. 10{sup 9} T and particle density n{sub 0} > or approx. 10{sup 36} m{sup -3}), where the SPF strongly dominates over the CPF. In other regimes, namely, B{sub 0} < or approx. 10{sup 8} T and n{sub 0} < or approx. 10{sup 35} m{sup -3}, where the SPF is comparable to the CPF, a plasma wakefield can also be excited self-consistently with one characteristic length scale. Numerical results reveal that the wakefield amplitude is enhanced by the quantum tunneling effect; however, it is lowered by the external magnetic field. Under appropriate conditions, the wakefields can maintain high coherence over multiple plasma wavelengths and thereby accelerate electrons to extremely high energies. The results could be useful for particle acceleration at short scales, i.e., at nanometer and micrometer scales, in magnetized dense plasmas where the driver is the whistler wave instead of a laser or a particle beam.

Misra, A. P.; Brodin, G.; Marklund, M. [Department of Physics, Umeaa University, SE-901 87 Umeaa (Sweden); Shukla, P. K. [Department of Physics, Umeaa University, SE-901 87 Umeaa (Sweden); RUB International Chair, International Centre for Advanced Studies in Physical Sciences, Faculty of Physics and Astronomy, Ruhr University Bochum, D-44780 Bochum (Germany)

2010-12-15T23:59:59.000Z

33

SLAC-PUB-8352 E-157: A 1.4 Meterlong Plasma Wakefield Acceleration Experiment Using a  

E-Print Network [OSTI]

beam of 2 x 1010 electrons in a 0.65mm long bunch is propagated through a 1.4m long Lithium plasma gradients, much in excess of 1 GeV/m, but over rather small ( acceleration of electrons by plasma wakefield acceleration with gradients in excess of 100 MeV/m over

34

Modeling Laser Wakefield Accelerators in a Lorentz Boosted Frame  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Modeling Laser Wakefield Accelerators in a Lorentz Boosted Frame Modeling Laser Wakefield Accelerators in a Lorentz Boosted Frame VayBoost.gif An image showing the "boosted frame,"...

35

Experimental demonstration of wakefield effects in a THz planar...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

energy chirp compensation * Self-wake energy modulation wakefield structure spectro meter Shaped beam energy chirped Shape + energy chirp energy change via self-wakefield...

36

Experimental demonstration of wakefield effects in a THz planar...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

ATF Users' Meetings, April 26 - 27, 2012 Wakefield Mapping wakefield structure spectro meter drive beam witness Experimental drive + witness visualization Spectrometer measurement...

37

Development of Ultra High Gradient and High Q{sub 0} Superconducting Radio Frequency Cavities  

SciTech Connect (OSTI)

We report on the recent progress at Jefferson Lab in developing ultra high gradient and high Q{sub 0} superconducting radio frequency (SRF) cavities for future SRF based machines. A new 1300 MHz 9-cell prototype cavity is being fabricated. This cavity has an optimized shape in terms of the ratio of the peak surface field (both magnetic and electric) to the acceleration gradient, hence the name low surface field (LSF) shape. The goal of the effort is to demonstrate an acceleration gradient of 50 MV/m with Q{sub 0} of 10{sup 10} at 2 K in a 9-cell SRF cavity. Fine-grain niobium material is used. Conventional forming, machining and electron beam welding method are used for cavity fabrication. New techniques are adopted to ensure repeatable, accurate and inexpensive fabrication of components and the full assembly. The completed cavity is to be first mechanically polished to a mirror-finish, a newly acquired in-house capability at JLab, followed by the proven ILC-style processing recipe established already at JLab. In parallel, new single-cell cavities made from large-grain niobium material are made to further advance the cavity treatment and processing procedures, aiming for the demonstration of an acceleration gradient of 50 MV/m with Q{sub 0} of 2?10{sup 10} at 2K.

Geng, Rongli [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Clemens, William A. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Follkie, James E. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Harris, Teena M. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Kushnick, Peter W. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Machie, Danny [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Martin, Robert E. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Palczewski, Ari D. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Perry, Era A. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Slack, Gary L. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Williams, R. S. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Adolphsen, C. [SLAC, Menlo Park, California, (United States); Li, Z. [SLAC, Menlo Park, California, (United States); Hao, J. K. [Peking University, Beijing (China); Li, Y. M. [Peking University, Beijing (China); Liu, K. X. [Peking University, Beijing (China)

2013-06-01T23:59:59.000Z

38

High Efficiency in Energy Generation from Salinity Gradients with Reverse Electrodialysis  

Science Journals Connector (OSTI)

High Efficiency in Energy Generation from Salinity Gradients with Reverse Electrodialysis ... Reverse electrodialysis; Renewable energy; Efficiency; Entropy; Salinity gradient energy; Ion exchange membranes ... power from the sequential flow of fresh and saline water, without the need for auxiliary processes or converters. ...

David A. Vermaas; Joost Veerman; Ngai Yin Yip; Menachem Elimelech; Michel Saakes; Kitty Nijmeijer

2013-08-02T23:59:59.000Z

39

Superconducting travelling wave ring with high gradient accelerating section  

SciTech Connect (OSTI)

Use of a superconducting traveling wave accelerating (STWA) structure instead of a standing wave cavity has major advantages in increasing the accelerating gradient in the ILC. In contrast with standing wave cavity STWA requires feedback loop, which sends wave from the structure output to input, making a superconducting traveling wave ring (STWR). One or few input couplers need to excite STWR and compensate power dissipations due to beam loading. To control traveling wave regime in the structure two independent knobs can be used for tuning both resonant ring frequency and backward wave. We discuss two variants of the STWR with one and two feed couplers.

Avrakhov, P.; Solyak, N.; /Fermilab

2007-06-01T23:59:59.000Z

40

High-Gradient Tests of the Single-Cell SC Cavity with a Feedback Waveguide  

SciTech Connect (OSTI)

Use of a superconducting (SC) traveling-wave accelerating (STWA) structure with a small phase advance per cell, rather than a standing-wave structure, may provide a significant increase in the accelerating gradient in the ILC linac [1]. For the same surface electric and magnetic fields, the STWA achieves an accelerating gradient 1.2 larger than TESLA-like standing-wave cavities. In addition, the STWA allows longer acceleration cavities, reducing the number of gaps between them. However, the STWA structure requires a SC feedback waveguide to return the few hundreds of MW of circulating RF power from the structure output to the structure input. A test single-cell cavity with feedback was designed and manufactured to demonstrate the possibility of proper processing to achieve a high accelerating gradient. The first results of high-gradient tests of a prototype 1.3 GHz single-cell cavity with feedback waveguide will be presented.

Yakovlev, V.; Solyak, N.; Wu, G.; Ge, M.; Gonin, I.; Khabiboulline, T.; Ozelis, J.; Rowe, A. [Fermilab, Batavia, IL 60510 (United States); Avrakhov, P.; Kanareykin, A. [Euclid TechLabs, LLC, Solon, Ohio 44139 (United States); Rathke, J. [AES, Medford, NY 11763 (United States)

2010-11-04T23:59:59.000Z

Note: This page contains sample records for the topic "high gradient wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

VOLUME 78, NUMBER 16 P H Y S I C A L R E V I E W L E T T E R S 21 APRIL 1997 Electron Acceleration by a Laser Wakefield in a Relativistically Self-Guided Channel  

E-Print Network [OSTI]

, x-ray lasers, and ultrahigh-gradient electron accelerators [2]. In the latter case, the field by a Laser Wakefield in a Relativistically Self-Guided Channel R. Wagner, S.-Y. Chen, A. Maksimchuk, and D-modulated laser wakefield is discussed. Above a power threshold, a relativistically self-guided channel from

Umstadter, Donald

42

Two GeV Electrons Achieved by Laser Plasma Wakefield Acceleration | U.S.  

Office of Science (SC) Website

Two GeV Electrons Achieved by Laser Plasma Wakefield Acceleration Two GeV Electrons Achieved by Laser Plasma Wakefield Acceleration High Energy Physics (HEP) HEP Home About Research Facilities Science Highlights Benefits of HEP Funding Opportunities Advisory Committees News & Resources Contact Information High Energy Physics U.S. Department of Energy SC-25/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-3624 F: (301) 903-2597 E: sc.hep@science.doe.gov More Information » July 2013 Two GeV Electrons Achieved by Laser Plasma Wakefield Acceleration Scientists at University of Texas, Austin, accelerate electrons to 2 GeV in table top apparatus. Print Text Size: A A A Subscribe FeedbackShare Page Click to enlarge photo. Enlarge Photo Image courtesy of Neil Fazel The inside of the University of Texas, Austin, vacuum chamber where

43

THE USE OF LARGE APERTURE ACCELERATING TUBES AT HIGH POTENTIAL GRADIENTS  

E-Print Network [OSTI]

observed in a mass analysis of the residual vacuum. Before removal of the accelerating tubes the mercury1507 THE USE OF LARGE APERTURE ACCELERATING TUBES AT HIGH POTENTIAL GRADIENTS J. H. BROADHURST John H. Williams Laboratory of Nuclear Physics, University of Minnesota, Minneapolis, Minnesota 55455, U

Paris-Sud XI, Université de

44

Development of High-Gradient Dielectric Laser-Driven Particle Accelerator Structures  

SciTech Connect (OSTI)

The thrust of Stanford's program is to conduct research on high-gradient dielectric accelerator structures driven with high repetition-rate, tabletop infrared lasers. The close collaboration between Stanford and SLAC (Stanford Linear Accelerator Center) is critical to the success of this project, because it provides a unique environment where prototype dielectric accelerator structures can be rapidly fabricated and tested with a relativistic electron beam.

Byer, Robert L.

2013-11-07T23:59:59.000Z

45

Laser-driven plasma-based accelerators: Wakefield excitation, channel guiding, and laser triggered particle injection*  

E-Print Network [OSTI]

Laser-driven plasma-based accelerators: Wakefield excitation, channel guiding, and laser triggered; accepted 18 February 1998 Plasma-based accelerators are discussed in which high-power short pulse lasers are the power source, suitably tailored plasma structures provide guiding of the laser beam and support large

Wurtele, Jonathan

46

Relativistic klystron driven compact high gradient accelerator as an injector to an X-ray synchrotron radiation ring  

DOE Patents [OSTI]

A compact high gradient accelerator driven by a relativistic klystron is utilized to inject high energy electrons into an X-ray synchrotron radiation ring. The high gradients provided by the relativistic klystron enables accelerator structure to be much shorter (typically 3 meters) than conventional injectors. This in turn enables manufacturers which utilize high energy, high intensity X-rays to produce various devices, such as computer chips, to do so on a cost effective basis.

Yu, David U. L. (1912 MacArthur St., Rancho Palos Verdes, CA 90732)

1990-01-01T23:59:59.000Z

47

Particle Capture Efficiency in a Multi-Wire Model for High Gradient Magnetic Separation  

E-Print Network [OSTI]

High gradient magnetic separation (HGMS) is an efficient way to remove magnetic and paramagnetic particles, such as heavy metals, from waste water. As the suspension flows through a magnetized filter mesh, high magnetic gradients around the wires attract and capture the particles, removing them from the fluid. We model such a system by considering the motion of a paramagnetic tracer particle through a periodic array of magnetized cylinders. We show that there is a critical Mason number (ratio of viscous to magnetic forces) below which the particle is captured irrespective of its initial position in the array. Above this threshold, particle capture is only partially successful and depends on the particle's entry position. We determine the relationship between the critical Mason number and the system geometry using numerical and asymptotic calculations. If a capture efficiency below 100% is sufficient, our results demonstrate how operating the HGMS system above the critical Mason number but with multiple separa...

Eisentrger, Almut; Griffiths, Ian M

2014-01-01T23:59:59.000Z

48

High gradient magnetic beneficiation of dry pulverized coal via upwardly directed recirculating fluidization  

DOE Patents [OSTI]

This invention relates to an improved device and method for the high gradient magnetic beneficiation of dry pulverized coal, for the purpose of removing sulfur and ash from the coal whereby the product is a dry environmentally acceptable, low-sulfur fuel. The process involves upwardly directed recirculating air fluidization of selectively sized powdered coal in a separator having sections of increasing diameters in the direction of air flow, with magnetic field and flow rates chosen for optimum separations depending upon particulate size.

Eissenberg, David M. (Oak Ridge, TN); Liu, Yin-An (Opelika, AL)

1980-01-01T23:59:59.000Z

49

Thermal gradient crystals as tuneable monochromator for high energy X-rays  

SciTech Connect (OSTI)

At the high energy synchrotron radiation beamline BW5 at DORIS III at DESY a new monochromator providing broad energy bandwidth and high reflectivity is in use. On a small 10x10x5 mm{sup 3} silicon crystal scattering at the (311) reflection a thermal gradient is applied, which tunes the scattered energy bandwidth. The (311) reflection strongly suppresses the higher harmonics allowing the use of an image plate detector for crystallography. The monochromator can be used at photon energies above 60 keV.

Ruett, U.; Schulte-Schrepping, H.; Heuer, J.; Zimmermann, M. von [Hamburger Synchrotron Strahlungslabor (HASYLAB), at Deutsches Elektronensychrotron (DESY), Notkestr. 85, 22603 Hamburg (Germany)

2010-06-23T23:59:59.000Z

50

Method and apparatus for fabrication of high gradient insulators with parallel surface conductors spaced less than one millimeter apart  

DOE Patents [OSTI]

Optical patterns and lithographic techniques are used as part of a process to embed parallel and evenly spaced conductors in the non-planar surfaces of an insulator to produce high gradient insulators. The approach extends the size that high gradient insulating structures can be fabricated as well as improves the performance of those insulators by reducing the scale of the alternating parallel lines of insulator and conductor along the surface. This fabrication approach also substantially decreases the cost required to produce high gradient insulators.

Sanders, David M. (Livermore, CA); Decker, Derek E. (Livermore, CA)

1999-01-01T23:59:59.000Z

51

A new high-gradient correction quadrupole for the Fermilab luminosity upgrade  

SciTech Connect (OSTI)

Special superconducting correction quadrupoles are needed for the luminosity upgrade of the Fermilab Tevatron Collider. These correctors are part of the low-beta system for the interaction regions at B/phi/ and D/phi/. The requirements are high gradient and low current. A quadrupole has been designed that meets the operating gradient of 0.63 T/cm at 1086 A. The one-layer quadrupole is wound with a cable consisting of five individually insulated rectangular strands. The five strands are overwrapped with Kapton and epoxy impregnated glass tape. The winding, curing and collaring of the magnet is accomplished in the same manner as Tevatron-like magnets using Rutherford style cable. Once the magnet is complete the five strands are connected in series. A prototype quadrupole has been assembled and tested. The magnet reached a plateau current of 1560 A corresponding to a gradient of 0.91 T/cm without training. The measured field harmonics are substantially better than required. 8 refs., 6 figs., 4 tabs.

Mantsch, P.; Carson, J.; Riddiford, A.; Lamm, M.J.

1989-03-01T23:59:59.000Z

52

Role of stochastic heating in wakefield acceleration when optical injection is used  

SciTech Connect (OSTI)

The dynamics of an electron in two counterpropagating waves is investigated. Conditions for stochastic acceleration are derived. The possibility of stochastic heating is confirmed when two waves interact with low density plasma by performing PIC (Particle In Cell) code simulations. It is shown that stochastic heating can play an important role in laser wakefield acceleration. When considering low density plasma interacting with a high intensity wave perturbed by a low intensity counterpropagating wave, stochastic heating can provide electrons with the right momentum for trapping in the wakefield. The influence of stochastic acceleration on the trapping of electrons is compared to the one of the beatwave force which is responsible for cold injection. To do so, several polarizations for the colliding pulses are considered. For some value of the plasma density and pulse duration, a transition from an injection due to stochastic acceleration to a cold injection dominated regimeregarding the trapped chargehas been observed from 2D and 3D PIC code simulations. This transition is ruled by the ratio of the interaction length of the pulses to the longitudinal size of the bubble. When the interaction length of the laser pulses reaches the radius of the accelerating cavity stochastic heating becomes dominant, and might be necessary to get electrons trapped into the wakefield, when wakefield inhibition grows with plasma density.

Rassou, S.; Bourdier, A.; Drouin, M. [CEA, DAM, DIF, 91297 Arpajon (France)

2014-08-15T23:59:59.000Z

53

UNDULATOR-BASED LASER WAKEFIELD ACCELERATOR ELECTRON BEAM DIAGNOSTIC  

SciTech Connect (OSTI)

to couple the THUNDER undulator to the LOASIS Lawrence Berkeley National Laboratory (LBNL) laser wakefield accelerator (LWFA). Currently the LWFA has achieved quasi-monoenergetic electron beams with energies up to 1 GeV. These ultra-short, high-peak-current, electron beams are ideal for driving a compact XUV free electron laser (FEL). Understanding the electron beam properties such as the energy spread and emittance is critical for achieving high quality light sources with high brightness. By using an insertion device such as an undulator and observing changes in the spontaneous emission spectrum, the electron beam energy spread and emittance can be measured with high precision. The initial experiments will use spontaneous emission from 1.5 m of undulator. Later experiments will use up to 5 m of undulator with a goal of a high gain, XUV FEL.

Bakeman, M.S.; Fawley, W.M.; Leemans, W. P.; Nakamura, K.; Robinson, K.E.; Schroeder, C.B.; Toth, C.

2009-05-04T23:59:59.000Z

54

Increasing the transformer ratio at the Argonne wakefield accelerator  

Science Journals Connector (OSTI)

The transformer ratio is defined as the ratio of the maximum energy gain of the witness bunch to the maximum energy loss experienced by the drive bunch (or a bunch within a multidrive bunch train). This plays an important role in the collinear wakefield acceleration scheme. A high transformer ratio is desirable since it leads to a higher overall efficiency under similar conditions (e.g. the same beam loading, the same structure, etc.). One technique to enhance the transformer ratio beyond the ordinary limit of 2 is to use a ramped bunch train. The first experimental demonstration observed a transformer ratio only marginally above 2 due to the mismatch between the drive microbunch length and the frequency of the accelerating structure [C. Jing, A. Kanareykin, J. Power, M. Conde, Z. Yusof, P. Schoessow, and W. Gai, Phys. Rev. Lett. 98, 144801 (2007)]. Recently, we revisited this experiment with an optimized microbunch length using a UV laser stacking technique at the Argonne Wakefield Accelerator facility and measured a transformer ratio of 3.4. Measurements and data analysis from these experiments are presented in detail.

C. Jing, J. G. Power, M. Conde, W. Liu, Z. Yusof, A. Kanareykin, and W. Gai

2011-02-16T23:59:59.000Z

55

Beam manipulation by self-wakefield at ATF  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Committee and the ATF Users' Meetings, April 26 - 27, 2012 Outline 1. Enhanced Transformer Ratio demonstration (wakefield mapping with the shaped beam) 2. Tunable beam energy...

56

Measurement of time dependent fields in high gradient superconducting quadrupoles for the Tevatron  

SciTech Connect (OSTI)

Magnetic field measurements have been performed on prototype and production magnets from two high gradient superconducting quadrupoles designs. One design is a double shell quadrupole with 36 strand Rutherford cable. The other design is a single shell quadrupole with 5 individually monolithic strands connected in series. These magnets have similar bore diameters and cable dimensions. However, there are significant differences between the two designs, as well as differences between prototype and production magnets within each design, with regard to Cu to superconductor ratio, filament diameter and filament spacing to strand diameter. The time dependence of fixed currents of the measured magnetic fields is discussed. 9 refs., 6 figs., 1 tab.

Lamm, M.J.; Coulter, K.; Gourlay, S.; Jaffery, T.S.

1990-10-01T23:59:59.000Z

57

Efficient operating mode of the plasma wakefield accelerator  

SciTech Connect (OSTI)

A new operating mode of the plasma wakefield accelerator is found at which high efficiency of the driver-to-witness energy exchange can be achieved simultaneously with high transformer ratio and low energy spread. The efficient acceleration is realized in the blowout regime with a high-current moderate-length driver, if most of the driver and the whole witness are inside the cavern, and the beams are shaped to flatten the profile of the longitudinal electric field. The efficient regime can be demonstrated with state-of-the-art electron beams, but requires a longitudinal compression of the drive beam, high density plasma, and precise control of driver and witness shapes.

Lotov, K.V. [Budker Institute of Nuclear Physics, 630090 Novosibirsk (Russian Federation)

2005-05-15T23:59:59.000Z

58

COLLECTION OF AIRBORNE PARTICLES BY A HIGH-GRADIENT PERMANENT MAGNETIC METHOD  

SciTech Connect (OSTI)

We report on the use of magnetic force in collection of airborne particles by a high- gradient permanent magnetic separation (HGPMS) device. Three aerosol particles of different magnetic susceptibility (NaCl, CuO, and Fe2O3) were generated in the electrical mobility size range of 10 to 200 nm and were used to study HGPMS collection. One HGPMS matrix element, made of stainless steel wool, was used in the device configuration. Three flow rates were selected to simulate the environmental wind speeds of interest to the study. Magnetic force was found to exhibit an insignificant effect on the separation of NaCl particles, even in the HGPMS configuration. Diffusion was a major mechanism in the removal of the diamagnetic particles; however, diffusion is insignificant under the influence of a high-gradient magnetic field for paramagnetic or ferromagnetic particles. The HGPMS showed high-performance collection (> 99%) of paramagnetic CuO and ferromagnetic Fe2O3 particles for particle sizes greater than or equal to 60 nm. As the wind speed increases, the influence of the magnetic force weakens, and the capability to remove particles from the gas stream diminishes. The results suggest that the HGPMS principle could be explored for development of an advanced miniaturized passive aerosol collector.

Cheng, Mengdawn [ORNL; Allman, Steve L [ORNL; Ludtka, Gerard Michael [ORNL; Avens, Larry R [ORNL

2014-01-01T23:59:59.000Z

59

Transverse Effect due to Short-range Resistive Wall Wakefield  

SciTech Connect (OSTI)

For accelerator designs with ultra short electron beams, beam dynamics study has to invoke the short-range wakefields. In this paper, we first obtain the short-range dipole mode resistive wall wakefield. Analytical approach is then developed to study the single bunch transverse beam dynamics due to this short-range resistive wall wake. The results are applied to the LCLS undulator.

Juhao Wu; Alex Chao; Jean Delayen

2007-06-18T23:59:59.000Z

60

Downramp-assisted underdense photocathode electron bunch generation in plasma wakefield accelerators  

E-Print Network [OSTI]

It is shown that the requirements for high quality electron bunch generation and trapping from an underdense photocathode in plasma wakefield accelerators can be substantially relaxed through localizing it on a plasma density downramp. This depresses the phase velocity of the accelerating electric field until the generated electrons are in phase, allowing for trapping in shallow trapping potentials. As a consequence the underdense photocathode technique is applicable by a much larger number of accelerator facilities. Furthermore, dark current generation is effectively suppressed.

Knetsch, Alexander; Wittig, Georg; Groth, Henning; Xi, Yunfeng; Deng, Aihua; Rosenzweig, James Benjamin; Bruhwiler, David Leslie; Smith, Johnathan; Jaroszynski, Dino Anthony; Sheng, Zheng-Ming; Manahan, Grace Gloria; Xia, Guoxing; Jamison, Steven; Hidding, Bernhard

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high gradient wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Evidence of Magnetic Breakdown on the Defects With Thermally Suppressed Critical Field in High Gradient SRF Cavities  

SciTech Connect (OSTI)

At SRF 2011 we presented the study of quenches in high gradient SRF cavities with dual mode excitation technique. The data differed from measurements done in 80's that indicated thermal breakdown nature of quenches in SRF cavities. In this contribution we present analysis of the data that indicates that our recent data for high gradient quenches is consistent with the magnetic breakdown on the defects with thermally suppressed critical field. From the parametric fits derived within the model we estimate the critical breakdown fields.

Eremeev, Grigory [JLAB; Palczewski, Ari [JLAB

2013-09-01T23:59:59.000Z

62

Coal Ranks and Geothermal Gradients in High-volatile Bituminous Coalfields  

Science Journals Connector (OSTI)

... 380; Sw. No., 6. If it is assumed that no great changes in geothermal gradient have occurred since the early Pleistocene, this coal was metamorphosed at a temperature ... Silesia5. The most obvious explanation is that of a nearly two to one difference in geothermal gradient. Comparison of data from the Carboniferous coalfields of the Netherlands with analyses of ...

R. P. SUGGATE; J. O. ELPHICK

1964-07-04T23:59:59.000Z

63

Wakefield Municipal Gas and Light Department - Residential Conservation  

Broader source: Energy.gov (indexed) [DOE]

Wakefield Municipal Gas and Light Department - Residential Wakefield Municipal Gas and Light Department - Residential Conservation Services Program Wakefield Municipal Gas and Light Department - Residential Conservation Services Program < Back Eligibility Residential Savings Category Home Weatherization Commercial Weatherization Sealing Your Home Heating & Cooling Commercial Heating & Cooling Cooling Appliances & Electronics Design & Remodeling Windows, Doors, & Skylights Manufacturing Commercial Lighting Lighting Water Heating Maximum Rebate Energy Audit Recommended Measures: $300 Programmable Thermostats: 2 units Program Info State Massachusetts Program Type Utility Rebate Program Rebate Amount Energy Audit Recommended Measures: 25% of total cost Refrigerators: $50 Clothes Washer: $50 Dishwasher: $50 Room AC: $50

64

Highly Robust Thin-Film Composite Pressure Retarded Osmosis (PRO) Hollow Fiber Membranes with High Power Densities for Renewable Salinity-Gradient Energy Generation  

Science Journals Connector (OSTI)

(1) Salinity-gradient energy (i.e., osmotic power) generated from the mixing of solutions with different salinities via pressure retarded osmosis (PRO) represents a high potential source of renewable energy. ... Thorsen, T.; Holt, T.The potential for power production from salinity gradients by pressure retarded osmosis J. Membr. ... When using saline water as the feed soln., the efficiency of the osmotic pressure decreases with increasing feed concn. ...

Gang Han; Peng Wang; Tai-Shung Chung

2013-06-17T23:59:59.000Z

65

Theory of factors limiting high gradient operation of warm accelerating structures  

SciTech Connect (OSTI)

This final report summarizes the research performed during the time period from 8/1/2010 to 7/31/2013. It consists of two parts describing our studies in two directions: (a) analysis of factors limiting operation of dielectric-loaded accelerating (DLA) structures where the main problem is the occurrence of multipactor on dielectric surfaces, and (b) studies of effects associated with either RF magnetic or RF electric fields which may cause the RF breakdown in high-gradient metallic accelerating structures. In the studies of DLA structures, at least, two accomplishments should be mentioned: the development of a 3D non-stationary, self-consistent code describing the multipactor phenomena and yielding very good agreement with some experimental data obtained in joint ANL/NRL experiments. In the metallic structures, such phenomena as the heating and melting of micro-particles (metallic dust) by RF electric and magnetic fields in single-shot and rep-rate regimes is analyzed. Also, such processes in micro-protrusions on the structure surfaces as heating and melting due to the field emitted current and the Nottingham effect are thoroughly investigated with the account for space charge of emitted current on the field emission from the tip.

Nusinovich, Gregory S. [University of Maryland; Antonsen, Thomas M. [University of Maryland; Kishek, Rami [University of Maryland

2014-07-25T23:59:59.000Z

66

AUGMENTING COMPUTER MUSIC WITH JUST-IN-TIME COMPILATION Wesley Smith, Graham Wakefield  

E-Print Network [OSTI]

AUGMENTING COMPUTER MUSIC WITH JUST-IN-TIME COMPILATION Wesley Smith, Graham Wakefield University of California Santa Barbara Media Arts and Technology whsmith|wakefield@mat.ucsb.edu ABSTRACT We discuss

California at Santa Barbara, University of

67

Plasma Focusing & Dielectric Wakefield Acceleration  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

pf pf Sign In Launch the Developer Dashboard SLAC National Accelerator Laboratory DOE | Stanford | SLAC | SSRL | LCLS | AD | PPA | Photon Science | PULSE | SIMES FACET User Facility : FACET An Office of Science User Facility Search this site... Search Help (new window) Top Link Bar FACET User Facility FACET Home About FACET FACET Experimental Facilities FACET Users Research at FACET SAREC Expand SAREC FACET FAQs FACET User Facility Quick Launch FACET Users Home FACET Division ARD Home About FACET FACET News FACET Users FACET Experimental Facilities FACET Research Expand FACET Research FACET Images Expand FACET Images SAREC Expand SAREC FACET Project Site (restricted) FACET FAQs FACET Site TOC All Site Content Department of Energy Page Content Plasma Focusing & Dielectric Wakefield Acceleration

68

Town of Wakefield, Massachusetts (Utility Company) | Open Energy  

Open Energy Info (EERE)

Wakefield Wakefield Place Massachusetts Utility Id 19979 Utility Location Yes Ownership M NERC Location NPCC NERC NPCC Yes Activity Buying Transmission Yes Activity Distribution Yes Activity Retail Marketing Yes Activity Bundled Services Yes References EIA Form EIA-861 Final Data File for 2010 - File1_a[1] LinkedIn Connections CrunchBase Profile No CrunchBase profile. Create one now! This article is a stub. You can help OpenEI by expanding it. Utility Rate Schedules Grid-background.png Commercial Rate B Commercial Domestic Electric Rate A Residential Power Rate C Industrial Average Rates Residential: $0.1510/kWh Commercial: $0.1410/kWh Industrial: $0.1240/kWh References ↑ "EIA Form EIA-861 Final Data File for 2010 - File1_a" Retrieved from "http://en.openei.org/w/index.php?title=Town_of_Wakefield,_Massachusetts_(Utility_Company)&oldid=41183

69

Town of Wakefield, Virginia (Utility Company) | Open Energy Information  

Open Energy Info (EERE)

Wakefield, Virginia (Utility Company) Wakefield, Virginia (Utility Company) Jump to: navigation, search Name Town of Wakefield Place Virginia Utility Id 19978 Utility Location Yes Ownership M NERC Location SERC NERC SERC Yes Activity Distribution Yes References EIA Form EIA-861 Final Data File for 2010 - File1_a[1] LinkedIn Connections CrunchBase Profile No CrunchBase profile. Create one now! This article is a stub. You can help OpenEI by expanding it. Utility Rate Schedules Grid-background.png Commercial Commercial Large Service Demand Industrial Out Town Residential Elec Residential Residential Residential Small Commercial Demand Commercial Average Rates Residential: $0.0855/kWh Commercial: $0.0855/kWh References ↑ "EIA Form EIA-861 Final Data File for 2010 - File1_a" Retrieved from

70

Measurements of Collimator Wakefields at End Station A  

SciTech Connect (OSTI)

The angular deflection of a 28.5 GeV electron beam passing off-axis between the jaws of a collimator, generating a transverse wakefield, were measured in End Station A (ESA) at SLAC. In total, fifteen different configurations of collimator geometry and material were tested: some were chosen for compatibility with previous measurements while others served to study the effect of geometry and taper angles (geometrical contribution to the wakefield) and the effect of the material resistivity (resistive contribution) to the imparted kick. This paper summarises the last update of preliminary experimental results before they are finalised. The reconstructed kick factor is compared to analytical calculations and simulations.

Fernandez-Hernando, J.L.; /Daresbury; Molloy, S.; /SLAC; Smith, J.D.A.; /Cockcroft Inst. Accel. Sci. Tech.; Watson, Nigel Keith; /Birmingham U.

2011-11-01T23:59:59.000Z

71

High energy X-ray diffraction study of a dental ceramicstitanium functional gradient material prepared by field assisted sintering technique  

Science Journals Connector (OSTI)

Abstract A functional gradient material with eleven layers composed of a dental ceramics and titanium was successfully consolidated using field assisted sintering technique in a two-step sintering process. High energy X-ray diffraction studies on the gradient were performed at High Energy Material Science beamline at Desy in Hamburg. Phase composition, crystal unit edges and lattice mismatch along the gradient were determined applying Rietveld refinement procedure. Phase analysis revealed that the main crystalline phase present in the gradient is ?-Ti. Crystallinity increases stepwisely along the gradient with a decreasing increment between every next layer, following rather the weight fraction of titanium. The crystal unit edge a of titanium remains approximately constant with a value of 2.9686(1), while c is reduced with increasing amount of titanium. In the layer with pure titanium the crystal unit edge c is constant with a value of 4.7174(2). The lattice mismatch leading to an internal stress was calculated over the whole gradient. It was found that the maximal internal stress in titanium embedded in the studied gradient is significantly smaller than its yield strength, which implies that the structure of titanium along the whole gradient is mechanically stable.

K. Witte; W. Bodnar; N. Schell; H. Lang; E. Burkel

2014-01-01T23:59:59.000Z

72

USING LUA FOR AUDIOVISUAL COMPOSTION Graham Wakefield Wesley Smith  

E-Print Network [OSTI]

USING LUA FOR AUDIOVISUAL COMPOSTION Graham Wakefield Wesley Smith University of California Santa Barbara Media Arts and Technology Program Santa Barbara, California, USA ABSTRACT In this paper, we/MSP/Jitter [27], PureData [19], etc.) are popular choices for composing interactive digital media works because

California at Santa Barbara, University of

73

Measurement of the Betatron Radiation Spectrum Coming From a Laser Wakefield Accelerator  

SciTech Connect (OSTI)

A Laser Wakefield Accelerator (LWFA) is under development at Lawrence Livermore National Laboratory (LLNL) to produce electron bunches with GeV class energy and energy spreads of a few-percent. The ultimate goal is to provide a bright and compact photon source for high energy density physics. The interaction of a high power (200 TW), short pulse (50 fs) laser with neutral He gas can generate quasi-monoenergetic electron beams at energies up to 1 GeV. The laser pulse can be self-guided over a dephasing length of 1 cm (for a plasma density of 1.5 x 10{sup 18} cm{sup -3}) overcoming the limitation of vacuum diffraction. Betatron radiation is emitted while the accelerated electrons undergo oscillations in the wakefield electrostatic field. Here we present electron spectra measurements with a two screen spectrometer allowing to fix the ambiguities due to electron deflections at the plasma exit. They have measured monoenergetic electron beams above 300 MeV. Furthermore a forward directed x-ray beam is observed. The measured betatron spectrum agrees well with the calculated spectrum in the synchrotron asymptotic limit (SAL) using the measured electron beam parameters.

Leurent, V; Michel, P; Clayton, C E; Pollock, B; Doeppner, T; Wang, T L; Ralph, J; Pak, A; Marsh, K; Joshi, C; Tynan, G R; Divol, L; Palastro, J P; Glenzer, S H; Froula, D H

2008-08-12T23:59:59.000Z

74

Exploring the effect of Al2O3 ALD coating on a high gradient ILC single-cell cavity  

SciTech Connect (OSTI)

Encouraged by work at Argonne National Lab, we investigated atomic layer deposition technique (ALD) for high gradient superconducting RF cavities at JLab with an ALD coating system of Old Dominion University located on the JLab site. The goal of this study was to look into the possibility of coating a dielectric layer on top of RF niobium surface at a lower temperature of 120 C as compared to ANL coatings at 200 C to preserve niobium pentoxide on niobium surface. The initial coatings showed complete, but non-uniform coatings of the surface with several areas exhibiting discoloration, which was probably due to the temperature variation across the cavity surface. The initial coating showed a high RF losses, which were improved after discolored areas on the beam tubes were removed with HF rinse of the beam tubes only. The best result was 2 109 low field Q0 and Eacc = 18 MV/m limited by available power.

Grigory Eremeev, Anne-Marie Valente, Andy Wu, Diefeng Gu

2012-07-01T23:59:59.000Z

75

FLUX-GRADIENT AND SOURCE TERM BALANCING FOR CERTAIN HIGH RESOLUTION SHOCK-CAPTURING SCHEMES  

E-Print Network [OSTI]

generation. Key Words: shallow water equations, high resolution shock capturing schemes, conservation Introduction Many practical problems involving shallow water flow in oceanography and atmospheric sciences in [8], for the shallow water system. We show that the use of two different Jacobians at cell interfaces

76

Cushman & Wakefield Environmental Challenge | ENERGY STAR Buildings &  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Cushman & Wakefield Environmental Challenge Cushman & Wakefield Environmental Challenge Secondary menu About us Press room Contact Us Portfolio Manager Login Facility owners and managers Existing buildings Commercial new construction Industrial energy management Small business Service providers Service and product providers Verify applications for ENERGY STAR certification Design commercial buildings Energy efficiency program administrators Commercial and industrial program sponsors Associations State and local governments Federal agencies Tools and resources Training In this section How can we help you? Build an energy program Improve building and plant performance Earn the ENERGY STAR and other recognition Benchmark energy use ENERGY STAR in action Communicate and educate ENERGY STAR communications toolkit Bring Your Green to Work with ENERGY STAR

77

Unphysical kinetic effects in particle-in-cell modeling of laser wakefield accelerators Estelle Cormier-Michel,1,2  

E-Print Network [OSTI]

Unphysical kinetic effects in particle-in-cell modeling of laser wakefield accelerators Estelle of laser wakefield accelerators using particle-in-cell codes are investigated. A dark current free laser wakefield accelerator stage, in which no trapping of background plasma electrons into the plasma wave should

Geddes, Cameron Guy Robinson

78

Emittance Measurements of Trapped Electrons from a Plasma Wakefield Accelerator  

SciTech Connect (OSTI)

Recent electron beam driven plasma wakefield accelerator experiments carried out at SLAC showed trapping of plasma electrons. These trapped electrons appeared on an energy spectrometer with smaller transverse size than the beam driving the wake. A connection is made between transverse size and emittance; due to the spectrometer's resolution, this connection allows for placing an upper limit on the trapped electron emittance. The upper limit for the lowest normalized emittance measured in the experiment is 1 mm {center_dot} mrad.

Kirby, N.; Berry, M.; Blumenfeld, I.; Decker, F.-J.; Hogan, M.J.; Ischebeck, R.; Iverson, R.; Siemann, R.; Walz, D.; /SLAC; Clayton, C.E.; Huang, C.; Joshi, C.; Lu, W.; Marsh, K.A.; Mori, W.B.; Zhou, M.; /UCLA; Katsouleas, T.C.; Muggli, P.; Oz, E.; /Southern California U.

2007-06-28T23:59:59.000Z

79

Transverse wakefields due to asymmetric protrusions into a vacuum chamber  

Science Journals Connector (OSTI)

Abstract We analyze the effect of a wakefield caused by an asymmetric protrusion inside the accelerator vacuum chamber. The asymmetry leads to a transverse kick on the beam and an increase of the projected transverse beam emittance. Calculations are done for a model rectangular protrusion in a vacuum chamber of rectangular cross-section. Based on our analysis, numerical estimates are given for the SuperKEKB accelerator in KEK, Japan, and TLEP-W proposal at CERN.

Gennady Stupakov; Demin Zhou

2014-01-01T23:59:59.000Z

80

The Pipe-Quadrupole, an Alternative for High Gradient Interaction Region Quadrupole Designs  

SciTech Connect (OSTI)

In the design of interaction region (IR) quadrupoles for high luminosity colliders such as the LHC or a possible upgrade of the Tevatron, the radiation heating of the coil windings is an important issue. Two obvious solutions to this problem can be chosen. The first is to reduce the heat load by added shielding, increased cooling with fins or using Nb{sub 3}Sn to increase the temperature margin. The second solution eliminates the conductor from the areas with the highest radiation intensity, which are located on the symmetry-axes of the midplanes of the coils. A novel quadrupole design is presented, in which the conductor is wound on four half-moon shaped supports, forming elongated toroid sections. The assembly of the four shapes yields a quadrupole field with an active flux return path, and a void in the high radiation area. This void can be occupied by a liquid helium cooling pipe to lower the temperature of the windings from the inside. The coil layout, harmonic optimization and mechanical design are shown, together with the calculated temperature rise for the radiation load of the LHC interaction region quadrupoles.

Oort, J.M. van; Scanlan, R.M.

1996-12-12T23:59:59.000Z

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81

Outline History Basic Theory Research Future Accelerators References Brief Overview of Wakefield  

E-Print Network [OSTI]

Outline History Basic Theory Research Future Accelerators References Brief Overview of Wakefield Acceleration Eugene S. Evans1 November 9, 2010 1 University of California, Berkeley Eugene S. Evans Brief Overview of Wakefield Acceleration #12;Outline History Basic Theory Research Future Accelerators References

Budker, Dmitry

82

Properties of Trapped Electron Bunches in a Plasma Wakefield Accelerator  

SciTech Connect (OSTI)

Plasma-based accelerators use the propagation of a drive bunch through plasma to create large electric fields. Recent plasma wakefield accelerator (PWFA) experiments, carried out at the Stanford Linear Accelerator Center (SLAC), successfully doubled the energy for some of the 42 GeV drive bunch electrons in less than a meter; this feat would have required 3 km in the SLAC linac. This dissertation covers one phenomenon associated with the PWFA, electron trapping. Recently it was shown that PWFAs, operated in the nonlinear bubble regime, can trap electrons that are released by ionization inside the plasma wake and accelerate them to high energies. These trapped electrons occupy and can degrade the accelerating portion of the plasma wake, so it is important to understand their origins and how to remove them. Here, the onset of electron trapping is connected to the drive bunch properties. Additionally, the trapped electron bunches are observed with normalized transverse emittance divided by peak current, {epsilon}{sub N,x}/I{sub t}, below the level of 0.2 {micro}m/kA. A theoretical model of the trapped electron emittance, developed here, indicates that the emittance scales inversely with the square root of the plasma density in the non-linear 'bubble' regime of the PWFA. This model and simulations indicate that the observed values of {epsilon}{sub N,x}/I{sub t} result from multi-GeV trapped electron bunches with emittances of a few {micro}m and multi-kA peak currents. These properties make the trapped electrons a possible particle source for next generation light sources. This dissertation is organized as follows. The first chapter is an overview of the PWFA, which includes a review of the accelerating and focusing fields and a survey of the remaining issues for a plasma-based particle collider. Then, the second chapter examines the physics of electron trapping in the PWFA. The third chapter uses theory and simulations to analyze the properties of the trapped electron bunches. Chapters four and five present the experimental diagnostics and measurements for the trapped electrons. Next, the sixth chapter introduces suggestions for future trapped electron experiments. Then, Chapter seven contains the conclusions. In addition, there is an appendix chapter that covers a topic which is extraneous to electron trapping, but relevant to the PWFA. This chapter explores the feasibility of one idea for the production of a hollow channel plasma, which if produced could solve some of the remaining issues for a plasma-based collider.

Kirby, Neil; /SLAC

2009-10-30T23:59:59.000Z

83

Vegetation along hydrologic, edaphic, and geochemical gradients in a high-elevation poor fen in Canaan Valley, West Virginia  

Science Journals Connector (OSTI)

Wetland plant community composition and pattern are regulated by a host of abiotic/environmental gradients and biotic factors. We used multivariate analyses to classify wetland plant communities and determine ...

James S. Rentch; James T. Anderson; Sam Lamont

2008-06-01T23:59:59.000Z

84

Self-Guided Laser Wakefield Acceleration beyond 1 GeV Using Ionization-Induced Injection  

SciTech Connect (OSTI)

The concepts of matched-beam, self-guided laser propagation and ionization-induced injection have been combined to accelerate electrons up to 1.45 GeV energy in a laser wakefield accelerator. From the spatial and spectral content of the laser light exiting the plasma, we infer that the 60 fs, 110 TW laser pulse is guided and excites a wake over the entire 1.3 cm length of the gas cell at densities below 1.5x10{sup 18} cm{sup -3}. High-energy electrons are observed only when small (3%) amounts of CO{sub 2} gas are added to the He gas. Computer simulations confirm that it is the K-shell electrons of oxygen that are ionized and injected into the wake and accelerated to beyond 1 GeV energy.

Clayton, C. E.; Joshi, C.; Lu, W.; Marsh, K. A.; Mori, W. B.; Pak, A.; Tsung, F. S. [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); Ralph, J. E.; Albert, F.; Glenzer, S. H.; Froula, D. H. [L-399, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States); Fonseca, R. A.; Martins, S. F.; Silva, L. O. [GoLP/IPFN-LA, Instituto Superior Tecnico, Lisboa (Portugal); Pollock, B. B.; Ross, J. S. [L-399, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States); MAE Department, University of California, San Diego, La Jolla, California 92093 (United States)

2010-09-03T23:59:59.000Z

85

Improvements to laser wakefield accelerated electron beam stability, divergence, and energy spread using three-dimensional printed two-stage gas cell targets  

SciTech Connect (OSTI)

High intensity, short pulse lasers can be used to accelerate electrons to ultra-relativistic energies via laser wakefield acceleration (LWFA) [T. Tajima and J. M. Dawson, Phys. Rev. Lett. 43, 267 (1979)]. Recently, it was shown that separating the injection and acceleration processes into two distinct stages could prove beneficial in obtaining stable, high energy electron beams [Gonsalves et al., Nat. Phys. 7, 862 (2011); Liu et al., Phys. Rev. Lett. 107, 035001 (2011); Pollock et al., Phys. Rev. Lett. 107, 045001 (2011)]. Here, we use a stereolithography based 3D printer to produce two-stage gas targets for LWFA experiments on the HERCULES laser system at the University of Michigan. We demonstrate substantial improvements to the divergence, pointing stability, and energy spread of a laser wakefield accelerated electron beam compared with a single-stage gas cell or gas jet target.

Vargas, M.; Schumaker, W.; He, Z.-H.; Zhao, Z.; Behm, K.; Chvykov, V.; Hou, B.; Krushelnick, K.; Maksimchuk, A.; Yanovsky, V.; Thomas, A. G. R., E-mail: agrt@umich.edu [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48109 (United States)

2014-04-28T23:59:59.000Z

86

Electron diffraction using ultrafast electron bunches from a laser-wakefield accelerator at kHz repetition rate  

SciTech Connect (OSTI)

We show that electron bunches in the 50-100 keV range can be produced from a laser wakefield accelerator using 10 mJ, 35 fs laser pulses operating at 0.5 kHz. It is shown that using a solenoid magnetic lens, the electron bunch distribution can be shaped. The resulting transverse and longitudinal coherence is suitable for producing diffraction images from a polycrystalline 10 nm aluminum foil. The high repetition rate, the stability of the electron source, and the fact that its uncorrelated bunch duration is below 100 fs make this approach promising for the development of sub-100 fs ultrafast electron diffraction experiments.

He, Z.-H.; Thomas, A. G. R.; Nees, J. A.; Hou, B.; Krushelnick, K. [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48106-2099 (United States)] [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48106-2099 (United States); Beaurepaire, B.; Malka, V.; Faure, J. [Laboratoire d'Optique Appliquee, ENSTA-CNRS-Ecole Polytechnique, UMR 7639, 91761 Palaiseau (France)] [Laboratoire d'Optique Appliquee, ENSTA-CNRS-Ecole Polytechnique, UMR 7639, 91761 Palaiseau (France)

2013-02-11T23:59:59.000Z

87

Validation of classical density-dependent solute transport theory for stable, high-concentration-gradient brine displacements in  

E-Print Network [OSTI]

-concentration-gradient brine displacements in coarse and medium sands S.J. Watson a,1 , D.A. Barry a,1 , R.J. Schotting b,*, S.M. Hassanizadeh b a School of Civil and Environmental Engineering, Contaminated Land Assessment and Remediation by a brine solution, under either constant head or constant volume flux conditions. The experimental data

Hassanizadeh, S. Majid

88

Beam Head Erosion in Self-Ionized Plasma Wakefield Accelerators  

SciTech Connect (OSTI)

In the recent plasma wakefield accelerator experiments at SLAC, the energy of the particles in the tail of the 42 GeV electron beam were doubled in less than one meter [1]. Simulations suggest that the acceleration length was limited by a new phenomenon--beam head erosion in self-ionized plasmas. In vacuum, a particle beam expands transversely in a distance given by {beta}*. In the blowout regime of a plasma wakefield [2], the majority of the beam is focused by the ion channel, while the beam head slowly spreads since it takes a finite time for the ion channel to form. It is observed that in self-ionized plasmas, the head spreading is exacerbated compared to that in pre-ionized plasmas, causing the ionization front to move backward (erode). A simple theoretical model is used to estimate the upper limit of the erosion rate for a bi-gaussian beam by assuming free expansion of the beam head before the ionization front. Comparison with simulations suggests that half this maximum value can serve as an estimate for the erosion rate. Critical parameters to the erosion rate are discussed.

Berry, M.K.; Blumenfeld, I.; Decker, F.J.; Hogan, M.J.; Ischebeck, R.; Iverson, R.H.; Kirby, N.A.; Siemann, Robert H.; Walz, D.R.; /SLAC; Clayton, C.E.; Huang, C.; Joshi, C.; Lu, W.; Marsh, K.A.; Mori, W.B.; Zhou, M.; /UCLA; Katsouleas, T.C.; Muggli, P.; Oz, E.; /Southern California U.

2008-01-28T23:59:59.000Z

89

Computational studies and optimization of wakefield accelerators  

E-Print Network [OSTI]

-frequency accelerators, offering compactness and ultrafast bunches to extend the frontiers of high energy physics behind recent demonstration of narrow energy spread bunches. Benchmarking between codes is establishing sources to design next-generation experiments and to use in applications in high energy physics and light

Geddes, Cameron Guy Robinson

90

Excitation of two-dimensional plasma wakefields by trains of equidistant particle bunches  

SciTech Connect (OSTI)

Nonlinear effects responsible for elongation of the plasma wave period are numerically studied with the emphasis on two-dimensionality of the wave. The limitation on the wakefield amplitude imposed by detuning of the wave and the driver is found.

Lotov, K. V. [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk, Russia and Novosibirsk State University, 630090 Novosibirsk (Russian Federation)] [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk, Russia and Novosibirsk State University, 630090 Novosibirsk (Russian Federation)

2013-08-15T23:59:59.000Z

91

Laser wakefield simulation using a speed-of-light frame envelope model  

E-Print Network [OSTI]

Laser wakefield simulation using a speed-of-light frame envelope model B. Cowan , D. Bruhwiler , E. By propagating the laser envelope in a frame moving at the speed of light, dispersive errors can be avoided

Geddes, Cameron Guy Robinson

92

Photocathode Studies at the Argonne Wakefield Accelerator  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Quantum Quantum Efficiency Photocathodes for the AWA High Energy Physics Division, ANL Zikri Yusof, Manoel Conde, Felipe Franchini Matt Virgo DOE Review April 26-27 2007 Energy Systems Division, ANL 2 PHOTOCATHODE REQUIREMENT FOR BUNCH TRAIN For the near future, creation of charge bunch train of 16 bunches in a single RF pulse 50 nC 16 micro pulses 5 eV Laser 10 mJ Want 50 nC in each charge microbunch. This is equal to ~ 3×10 11 electrons. * 10 mJ of laser energy per pulse; * Estimate 80% loss due to beam splitter, mirrors, etc.; * Beam is split into 16 micro pulses; * Number of photons in each micro pulse is ~1.5×10 14 . QE of photocathode to be able to supply that amount of charge: % 2 . 0 10 2 10 5 . 1 10 3 3 14 11 = × ≈ × × = - QE Need high QE photocathode - choose Cs 2 Te 770 ps 3 Cs 2 Te RECIPE

93

Cushman & Wakefields Client Solutions Group presents:  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

OCTOBER 2009 OCTOBER 2009 Updated January 2010 A CALL TO ACTION TO IMPROVE THE ENVIRONMENTAL EFFICIENCY OF CUSHMAN &WAKEFIELD'S MANAGED PROPERTIES Take the C&W Environmental Challenge and help us find out: * Who can quantify improvements in environmental performance over time? * Who can take environmental performance to the next level? * Which buildings are the highest performers across C&W managed portfolio? WHAT IS THE C&W ENVIRONMENTAL CHALLENGE? WHY PARTICIPATE? IMPROVE YOUR BOTTOM LINE: Increased energy and water efficiency, and reduced waste in commercial real estate can reduce operating expenses and increase property asset value. DO YOUR PART TO ADDRESS CLIMATE CHANGE: Commercial buildings generate about 17% of total greenhouse gas emissions.

94

Meter scale plasma source for plasma wakefield experiments  

SciTech Connect (OSTI)

High accelerating gradients generated by a high density electron beam moving through plasma has been used to double the energy of the SLAC electron beam [1]. During that experiment, the electron current density was high enough to generate its own plasma without significant head erosion. In the newly commissioned FACET facility at SLAC, the peak current will be lower and without pre-ionization, head erosion will be a significant challenge for the planned experiments. In this work we report on our design of a meter scale plasma source for these experiments to effectively avoid the problem of head erosion. The plasma source is based on a homogeneous metal vapor gas column that is generated in a heat pipe oven [2]. A lithium oven over 30 cm long at densities over 10{sup 17} cm{sup -3} has been constructed and tested at UCLA. The plasma is then generated by coupling a 10 TW short pulse Ti:Sapphire laser into the gas column using an axicon lens setup. The Bessel profile of the axicon setup creates a region of high intensity that can stretch over the full length of the gas column with approximately constant diameter. In this region of high intensity, the alkali metal vapor is ionized through multi-photon ionization process. In this manner, a fully ionized meter scale plasma of uniform density can be formed. Methods for controlling the plasma diameter and length will also be discussed.

Vafaei-Najafabadi, N.; Shaw, J. L.; Marsh, K. A.; Joshi, C.; Hogan, M. J. [Department of Electrical Engineering, University of California Los Angeles, Los Angeles, CA 90095 (United States); SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States)

2012-12-21T23:59:59.000Z

95

A multi-beam, multi-terawatt Ti:sapphire laser system for laser wake-field acceleration studies  

E-Print Network [OSTI]

­plasma interaction studies, such as development of laser wake-field accelerators [1-4], X-ray lasers, and laserA multi-beam, multi-terawatt Ti:sapphire laser system for laser wake-field acceleration studies 71R0259, 1 Cyclotron Rd., Berkeley, CA 94720, USA, e-mail: ctoth@lbl.gov Abstract. The Lasers

Geddes, Cameron Guy Robinson

96

2012 SG Peer Review - Day 2 Panel Discussion: Matt Wakefield, EPRI  

Broader source: Energy.gov (indexed) [DOE]

Matt Wakefield Matt Wakefield Senior Program Manager, Smart Grid June 7, 2012 Overview & Industry Coordination of EPRI IntelliGrid & Security Research & Smart Grid Demonstrations 2 © 2012 Electric Power Research Institute, Inc. All rights reserved. IntelliGrid Program Information & Communication Technologies (ICT) to Enable..... The IntelliGrid Program conducts research, development and demonstrations on the Information and Communications Technologies (ICT) that Enable Smart Grid applications IntelliGrid * Transmission * Distribution * End-Use (AMI/DR) 3 © 2012 Electric Power Research Institute, Inc. All rights reserved. * Reliability and performance characteristics the various technology

97

Scaling of the Longitudinal Electric Field and Transformer Ratio in a Nonlinear Plasma Wakefield Accelerator  

SciTech Connect (OSTI)

The scaling of the two important figures of merit, the transformer ratio T and the longitudinal electric field E{sub z}, with the peak drive-bunch current I{sub p}, in a nonlinear plasma wakefield accelerator is presented for the first time. The longitudinal field scales as I{sub P}{sup 0.623{+-}0.007}, in good agreement with nonlinear wakefield theory ({approx}I{sub P}{sup 0.5}), while the unloaded transformer ratio is shown to be greater than unity and scales weakly with the bunch current. The effect of bunch head erosion on both parameters is also discussed.

Blumenfeld, I.; /SLAC; Clayton, C.E.; /UCLA; Decker, F.J.; Hogan, M.J.; /SLAC; Huang, C.; /UCLA; Ischebeck, R.; Iverson, R.H.; /SLAC; Joshi, C.; /UCLA; Katsouleas, T.; /Southern California U.; Kirby, N.; /SLAC; Lu, W.; Marsh, K.A.; Mori, W.B.; /UCLA; Muggli, P.; Oz, E.; /Southern California U.; Siemann, R.H.; Walz, D.R.; /SLAC; Zhou, M.; /UCLA

2012-06-12T23:59:59.000Z

98

Effect of plasma inhomogeneity on plasma wakefield acceleration driven by long bunches  

SciTech Connect (OSTI)

Effects of plasma inhomogeneity on self-modulating proton bunches and accelerated electrons were studied numerically. The main effect is the change of the wakefield wavelength which results in phase shifts and loss of accelerated particles. This effect imposes severe constraints on density uniformity in plasma wakefield accelerators driven by long particle bunches. The transverse two stream instability that transforms the long bunch into a train of micro-bunches is less sensitive to density inhomogeneity than are the accelerated particles. The bunch freely passes through increased density regions and interacts with reduced density regions.

Lotov, K. V. [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk, Russia and Novosibirsk State University, 630090 Novosibirsk (Russian Federation); Pukhov, A. [Institut fuer Theoretische Physik I, Heinrich-Heine-Universitaet Duesseldorf, 40225 Duesseldorf (Germany); Caldwell, A. [Max-Planck-Institut fuer Physik, 80805 Muenchen (Germany)

2013-01-15T23:59:59.000Z

99

Frequency chirp and pulse shape effects in self-modulated laser wakefield acceleratorsa...  

E-Print Network [OSTI]

laser-plasma-based harmonic generation,2 x-ray lasers,3 and laser-driven inertial confinement fusionFrequency chirp and pulse shape effects in self-modulated laser wakefield acceleratorsa... C. B Received 7 November 2002; accepted 20 January 2003 The effect of asymmetric laser pulses on plasma wave

Geddes, Cameron Guy Robinson

100

Spectroscopy of betatron radiation emitted from laser-produced wakefield accelerated electronsa...  

E-Print Network [OSTI]

laser facilities in which the nature divergence and total x-ray flux of the betatron radiation has been is able to discern changes of the betatron emission x-ray spec- trum with differing laser parametersSpectroscopy of betatron radiation emitted from laser-produced wakefield accelerated electronsa

Geddes, Cameron Guy Robinson

Note: This page contains sample records for the topic "high gradient wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Monte Carlo Characterization of a Pulsed Laser-Wakefield Driven Monochromatic  

E-Print Network [OSTI]

Monte Carlo Characterization of a Pulsed Laser-Wakefield Driven Monochromatic X-Ray Source S. D determination of the incident X-ray energy by using unfolding techniques. I. INTRODUCTION HE Diocles laser light from the same laser system, producing monochromatic X-rays with energy and spectral width

Umstadter, Donald

102

Multimode Analysis of the Hollow Plasma Channel Wakefield Accelerator C. B. Schroeder,1  

E-Print Network [OSTI]

this breakdown constraint. Two schemes of plasma excitation have been the focus of much of the work: the laserMultimode Analysis of the Hollow Plasma Channel Wakefield Accelerator C. B. Schroeder,1 D. H April 1998) The hollow plasma channel is analyzed as an accelerating structure. The excitation

Geddes, Cameron Guy Robinson

103

LuaAV: Extensibility and Heterogeneity for Audiovisual Graham WAKEFIELD and Wesley SMITH and Charles ROBERTS  

E-Print Network [OSTI]

LuaAV: Extensibility and Heterogeneity for Audiovisual Computing Graham WAKEFIELD and Wesley SMITH and Charles ROBERTS Media Arts and Technology, University of California Santa Barbara Santa Barbara, CA 93110 providing the flexibility and temporal accuracy demanded by interactive audio-visual media. Code generation

California at Santa Barbara, University of

104

Identification of small-scale low and high permeability layers using single well forced-gradient tracer tests: Fluorescent dye imaging and modelling at the laboratory-scale  

Science Journals Connector (OSTI)

Abstract Heterogeneity in aquifer permeability, which creates paths of varying mass flux and spatially complex contaminant plumes, can complicate the interpretation of contaminant fate and transport in groundwater. Identifying the location of high mass flux paths is critical for the reliable estimation of solute transport parameters and design of groundwater remediation schemes. Dipole flow tracer tests (DFTTs) and push-pull tests (PPTs) are single well forced-gradient tests which have been used at field-scale to estimate aquifer hydraulic and transport properties. In this study, the potential for \\{PPTs\\} and \\{DFTTs\\} to resolve the location of layered high- and low-permeability layers in granular porous media was investigated with a pseudo 2-D bench-scale aquifer model. Finite element fate and transport modelling was also undertaken to identify appropriate set-ups for in situ tests to determine the type, magnitude, location and extent of such layered permeability contrasts at the field-scale. The characteristics of flow patterns created during experiments were evaluated using fluorescent dye imaging and compared with the breakthrough behaviour of an inorganic conservative tracer. The experimental results show that tracer breakthrough during \\{PPTs\\} is not sensitive to minor permeability contrasts for conditions where there is no hydraulic gradient. In contrast, \\{DFTTs\\} are sensitive to the type and location of permeability contrasts in the host media and could potentially be used to establish the presence and location of high or low mass flux paths. Numerical modelling shows that the tracer peak breakthrough time and concentration in a DFTT is sensitive to the magnitude of the permeability contrast (defined as the permeability of the layer over the permeability of the bulk media) between values of 0.0120. \\{DFTTs\\} are shown to be more sensitive to deducing variations in the contrast, location and size of aquifer layered permeability contrasts when a shorter central packer is used. However, larger packer sizes are more likely to be practical for field-scale applications, with fewer tests required to characterise a given aquifer section. The sensitivity of \\{DFTTs\\} to identify layered permeability contrasts was not affected by test flow rate.

Gareth L. Barns; Steven F. Thornton; Ryan D. Wilson

2015-01-01T23:59:59.000Z

105

Injection and acceleration of electron bunch in a plasma wakefield produced by a chirped laser pulse  

SciTech Connect (OSTI)

An ultrashort laser pulse propagating in plasma can excite a nonlinear plasma wakefield which can trap and accelerate charged particles up to GeV. One-dimensional analysis of electron injection, trapping, and acceleration by different chirped pulses propagating in plasma is investigated numerically. In this paper, we inject electron bunches in front of the chirped pulses. It is indicated that periodical chirped laser pulse can trap electrons earlier than other pulses. It is shown that periodical chirped laser pulses lead to decrease the minimum momentum necessary to trap the electrons. This is due to the fact that periodical chirped laser pulses are globally much efficient than nonchirped pulses in the wakefield generation. It is found that chirped laser pulses could lead to much larger electron energy than that of nonchirped pulses. Relative energy spread has a lower value in the case of periodical chirped laser pulses.

Afhami, Saeedeh; Eslami, Esmaeil, E-mail: eeslami@iust.ac.ir [Department of Physics, Iran University of Science and Technology (IUST), Narmak, Tehran 16846-13114 (Iran, Islamic Republic of)

2014-06-15T23:59:59.000Z

106

Emittance and Current of Electrons Trapped in a Plasma Wakefield Accelerator  

SciTech Connect (OSTI)

In recent experiments plasma electrons became trapped in a plasma wakefield accelerator (PWFA). The transverse size of these trapped electrons on a downstream diagnostic yields an upper limit measurement of transverse normalized emittance divided by peak current, {epsilon}{sub N,{sub x}}/I. The lowest upper limit for {epsilon}{sub N,{sub x}}/I measured in the experiment is 1.3{center_dot}10{sup -10} m/A.

Kirby, N.; Blumenfeld, I.; Decker, F. J.; Hogan, M. J.; Ischebeck, R.; Iverson, R. H.; Siemann, R. H.; Walz, D. R. [Stanford Linear Accelerator Center, Stanford University, Stanford, California 94305 (United States); Clayton, C. E.; Huang, C.; Joshi, C.; Lu, W.; Marsh, K. A.; Mori, W. B.; Zhou, M. [University of California, Los Angeles, California 90095 (United States); Katsouleas, T.; Muggli, P.; Oz, E. [University of Southern California, Los Angeles, California 90089 (United States); Martins, S. [GoLP/IPFN, Instituto Superior Tecnico (Portugal)

2009-01-22T23:59:59.000Z

107

Electron Bunch Length Measurements in the E-167 Plasma Wakefield Experiment  

SciTech Connect (OSTI)

Bunch length is of prime importance to beam driven plasma wakefield acceleration experiments due to its inverse relationship to the amplitude of the accelerating wake. We present here a summary of work done by the E167 collaboration measuring the SLAC ultra-short bunches via autocorrelation of coherent transition radiation. We have studied material transmission properties and improved our autocorrelation traces using materials with better spectral characteristics.

Blumenfeld, I.; Auerbach, D.; Berry, M.; Clayton, C.E.; Decker, F.J.; Hogan, M.J.; Huang, Cheng-Kun; Ischebeck, R.; Iverson, R.; Johnson, D.; Joshi, C.; Katsouleas, T.; Kirby, N.; Lu, Wei; Marsh, K.A.; Mori, W.B.; Muggli, P.; Oz, E.; Siemann, R.H.; Walz, D.; Zacherl, W.; /SLAC /UCLA /Southern California U.

2007-03-27T23:59:59.000Z

108

Plasma Wakefield Acceleration and FACET - Facilities for Accelerator Science and Experimental Test Beams at SLAC  

ScienceCinema (OSTI)

Plasma wakefield acceleration is one of the most promising approaches to advancing accelerator technology. This approach offers a potential 1,000-fold or more increase in acceleration over a given distance, compared to existing accelerators. FACET, enabled by the Recovery Act funds, will study plasma acceleration, using short, intense pulses of electrons and positrons. In this lecture, the physics of plasma acceleration and features of FACET will be presented.

Andrei Seryi

2010-01-08T23:59:59.000Z

109

High Gradient Acceleration in a 17 GHz Photocathode RF Gun* S. C. Chen, J. Gonichon, 1;. C-L. Lin, R. J. Temkin, S. Trotz, B. G. Danly, and J. S. Wurtele  

E-Print Network [OSTI]

High Gradient Acceleration in a 17 GHz Photocathode RF Gun* S. C. Chen, J. Gonichon, 1;. C-L. Lin.icle acceleration at high mi- ccowave (RF) frequencies are under study at hIIT. The 17 GHz photocathode RF gun has, efforts have been made recent,ly t,o creat,e novel electron beam sources.[l] While existing RF guns

Wurtele, Jonathan

110

Simulations of Jitter Coupling due to Wakefields in the FACET Linac  

SciTech Connect (OSTI)

Facilities for Accelerator Science and Experimental Test Beams (FACET) is a proposed facility at SLAC that would use the initial two-thirds of the linac to transport e{sup +} and e{sup -} beams to an experimental region. A principal use of this facility is to identify the optimum method for accelerating positrons in a beam driven plasma wakefield accelerator. To study this, a positron bunch, followed an RF-cycle later by an electron bunch, will be accelerated to an asymmetric chicane designed to move the positrons behind the electrons, and then on to the plasma wakefield test stand. A major focus of study was the coupling of jitter of the positron bunch to the electron bunch via linac wakes. Lucretia is a Matlab toolbox for the simulation of electron beam transport systems, capable of multi-bunch tracking and wakefield calculations. With the exception of the lack of support for tracking of electrons and positrons within a single bunch train, it was well suited to the jitter coupling studies. This paper describes the jitter studies, including modifications made to Lucretia to correctly simulate tracking of mixed-species bunch trains through a lattice of magnetic elements and EM wakes.

Molloy, Stephen

2009-10-30T23:59:59.000Z

111

Fast Self-Healing Gradients  

E-Print Network [OSTI]

We present CRF-Gradient, a self-healing gradient algorithm that provably reconfigures in O(diameter) time. Self-healing gradients are a frequently used building block for distributed self-healing systems, but previous ...

Beal, Jacob

112

Spectrum bandwidth narrowing of Thomson scattering X-rays with energy chirped electron beams from laser wakefield acceleration  

SciTech Connect (OSTI)

We study incoherent Thomson scattering between an ultrashort laser pulse and an electron beam accelerated from a laser wakefield. The energy chirp effects of the accelerated electron beam on the final radiation spectrum bandwidth are investigated. It is found that the scattered X-ray radiation has the minimum spectrum width and highest intensity as electrons are accelerated up to around the dephasing point. Furthermore, it is proposed that the electron acceleration process inside the wakefield can be studied by use of 90 Thomson scattering. The dephasing position and beam energy chirp can be deduced from the intensity and bandwidth of the scattered radiation.

Xu, Tong; Chen, Min, E-mail: minchen@sjtu.edu.cn; Li, Fei-Yu; Yu, Lu-Le [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China)] [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Sheng, Zheng-Ming, E-mail: zmsheng@sjtu.edu.cn [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China) [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Zhang, Jie [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China) [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, CAS, Beijing 100190 (China)

2014-01-06T23:59:59.000Z

113

Two-Screen Method for Determining Electron Beam Energy and Deflection from Laser Wakefield Acceleration  

SciTech Connect (OSTI)

Laser Wakefield Acceleration (LWFA) experiments have been performed at the Jupiter Laser Facility, Lawrence Livermore National Laboratory. In order to unambiguously determine the output electron beam energy and deflection angle at the plasma exit, we have implemented a two-screen electron spectrometer. This system is comprised of a dipole magnet followed by two image plates. By measuring the electron beam deviation from the laser axis on each plate, both the energy and deflection angle at the plasma exit are determined through the relativistic equation of motion.

Pollock, B B; Ross, J S; Tynan, G R; Divol, L; Glenzer, S H; Leurent, V; Palastro, J P; Ralph, J E; Froula, D H; Clayton, C E; Marsh, K A; Pak, A E; Wang, T L; Joshi, C

2009-04-24T23:59:59.000Z

114

Hot Pot Contoured Temperature Gradient Map  

SciTech Connect (OSTI)

Temperature gradient contours derived from Oski temperature gradient hole program and from earlier published information.

Lane, Michael

2013-06-28T23:59:59.000Z

115

Hot Pot Contoured Temperature Gradient Map  

DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

Temperature gradient contours derived from Oski temperature gradient hole program and from earlier published information.

Lane, Michael

116

Recurrent policy gradients  

Science Journals Connector (OSTI)

......for recurrent neural networks Recurrent policy gradients Daan Wierstra Alexander Forster...POMDPs) is a challenge as it requires policies with an internal state. Traditional approaches...offer a natural framework for dealing with policy learning using hidden state and require......

Daan Wierstra; Alexander Frster; Jan Peters; Jrgen Schmidhuber

2010-10-01T23:59:59.000Z

117

A Proposal for a 1 GeV Plasma-Wakefield Acceleration Experiment at SLAC T. Katsouleas, S. Lee, USC  

E-Print Network [OSTI]

, USC Los Angeles, CA 90089-0484 S. Chattopadhyay, W. Leemans, LBNL R. Assmann, P. Chen, F.J. Decker, R. Iverson, T. Kotseroglou, P. Raimondi, T. Raubenheimer, S. Rokni, R.H. Siemann, D. Walz, D. Whittum, SLAC C. Clayton, C. Joshi, K. Marsh, W. Mori, G. Wang, UCLA Abstract A plasma-based wakefield acceleration (PWFA

118

Tunable Electron Multibunch Production in Plasma Wakefield Accelerators  

E-Print Network [OSTI]

Synchronized, independently tunable and focused $\\mu$J-class laser pulses are used to release multiple electron populations via photo-ionization inside an electron-beam driven plasma wave. By varying the laser foci in the laboratory frame and the position of the underdense photocathodes in the co-moving frame, the delays between the produced bunches and their energies are adjusted. The resulting multibunches have ultra-high quality and brightness, allowing for hitherto impossible bunch configurations such as spatially overlapping bunch populations with strictly separated energies, which opens up a new regime for light sources such as free-electron-lasers.

Hidding, B; Wittig, G; Aniculaesei, C; Jaroszynski, D; McNeil, B W J; Campbell, L T; Islam, M R; Ersfeld, B; Sheng, Z -M; Xi, Y; Deng, A; Rosenzweig, J B; Andonian, G; Murokh, A; Hogan, M J; Bruhwiler, D L; Cormier, E

2014-01-01T23:59:59.000Z

119

Self-truncated ionization injection and consequent monoenergetic electron bunches in laser wakefield acceleration  

SciTech Connect (OSTI)

The ionization-induced injection in laser wakefield acceleration has been recently demonstrated to be a promising injection scheme. However, the energy spread controlling in this mechanism remains a challenge because continuous injection in a mixed gas target is usually inevitable. Here, we propose that by use of certain initially unmatched laser pulses, the electron injection can be constrained to the very front region of the mixed gas target, typically in a length of a few hundreds micrometers determined by the laser self-focusing and the wake deformation. As a result, the produced electron beam has narrow energy spread and meanwhile contains tens of pC in charge. Both multidimensional simulations and theoretical analysis illustrate the effectiveness of this scheme.

Zeng, Ming; Zhang, Jie [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China)] [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Chen, Min, E-mail: minchen@sjtu.edu.cn [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China) [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Department of Mathematics, Institute of Natural Sciences, and MOE-LSC, Shanghai Jiao Tong University, Shanghai 20040 (China); Sheng, Zheng-Ming, E-mail: zmsheng@sjtu.edu.cn [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China) [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Mori, Warren B. [University of California, Los Angeles, California 90095 (United States)] [University of California, Los Angeles, California 90095 (United States)

2014-03-15T23:59:59.000Z

120

Measurements of the critical power for self-injection of electrons in a laser wakefield accelerator  

SciTech Connect (OSTI)

A laser wakefield acceleration study has been performed in the matched, self-guided, blow-out regime where a 10 J, 60 fs laser produced 720 {+-} 50 MeV quasi-monoenergetic electrons with a divergence of {Delta}{theta} = 2.85 {+-} 0.15 mRad. While maintaining a nearly constant plasma density (3 x 10{sup 18} cm{sup -3}), a linear electron energy gain was measured from 100 MeV to 700 MeV when the plasma length was scaled from 3 mm to 8 mm. Absolute charge measurements indicate that self-injection occurs when P/P{sub cr} > 4 and saturates around 100 pC for P/P{sub cr} > 12. The results are compared with both analytical scalings and full 3D particle-in-cell simulations.

Froula, D H; Clayton, C E; Doppner, T; Fonseca, R A; Marsh, K A; Barty, C J; Divol, L; Glenzer, S H; Joshi, C; Lu, W; Martins, S F; Michel, P; Mori, W; Palastro, J P; Pollock, B B; Pak, A; Ralph, J E; Ross, J S; Siders, C; Silva, L O; Wang, T

2009-06-02T23:59:59.000Z

Note: This page contains sample records for the topic "high gradient wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Frequency chirp and pulse shape effects in self-modulated laser wakefield accelerators  

SciTech Connect (OSTI)

The effect of asymmetric laser pulses on plasma wave excitation in a self-modulated laser wakefield accelerator is examined. Laser pulse shape and frequency chirp asymmetries, controlled experimentally in the laser system through a grating pair compressor, are shown to strongly enhance measured electron yields for certain asymmetries. It is shown analytically that a positive (negative) frequency chirp enhances (suppresses) the growth rate of the Raman forward scattering and near-forward Raman sidescatter instabilities, but is of minimal importance for the experimental parameters. Temporal laser pulse shapes with fast rise times (< plasma period) are shown to generate larger wakes (compared to slow rise time pulses) which seed the growth of the plasma wave, resulting in enhanced electron yield.

Schroeder, C.B.; Esarey, E.; Geddes, C.G.R.; Toth, Cs.; Shadwick, B.A.; van Tilborg, J.; Faure, J.; Leemans, W.P.

2002-11-07T23:59:59.000Z

122

Experimental determination of the radial dose distribution in high gradient regions around {sup 192}Ir wires: Comparison of electron paramagnetic resonance imaging, films, and Monte Carlo simulations  

SciTech Connect (OSTI)

Purpose: The experimental determination of doses at proximal distances from radioactive sources is difficult because of the steepness of the dose gradient. The goal of this study was to determine the relative radial dose distribution for a low dose rate {sup 192}Ir wire source using electron paramagnetic resonance imaging (EPRI) and to compare the results to those obtained using Gafchromic EBT film dosimetry and Monte Carlo (MC) simulations. Methods: Lithium formate and ammonium formate were chosen as the EPR dosimetric materials and were used to form cylindrical phantoms. The dose distribution of the stable radiation-induced free radicals in the lithium formate and ammonium formate phantoms was assessed by EPRI. EBT films were also inserted inside in ammonium formate phantoms for comparison. MC simulation was performed using the MCNP4C2 software code. Results: The radical signal in irradiated ammonium formate is contained in a single narrow EPR line, with an EPR peak-to-peak linewidth narrower than that of lithium formate ({approx}0.64 and 1.4 mT, respectively). The spatial resolution of EPR images was enhanced by a factor of 2.3 using ammonium formate compared to lithium formate because its linewidth is about 0.75 mT narrower than that of lithium formate. The EPRI results were consistent to within 1% with those of Gafchromic EBT films and MC simulations at distances from 1.0 to 2.9 mm. The radial dose values obtained by EPRI were about 4% lower at distances from 2.9 to 4.0 mm than those determined by MC simulation and EBT film dosimetry. Conclusions: Ammonium formate is a suitable material under certain conditions for use in brachytherapy dosimetry using EPRI. In this study, the authors demonstrated that the EPRI technique allows the estimation of the relative radial dose distribution at short distances for a {sup 192}Ir wire source.

Kolbun, N.; Leveque, Ph.; Abboud, F.; Bol, A.; Vynckier, S.; Gallez, B. [Biomedical Magnetic Resonance Unit, Louvain Drug Research Institute, Universite catholique de Louvain, Avenue Mounier 73.40, B-1200 Brussels (Belgium); Molecular Imaging and Experimental Radiotherapy Unit, Institute of Experimental and Clinical Research, Universite catholique de Louvain, Avenue Hippocrate 55, B-1200 Brussels (Belgium); Biomedical Magnetic Resonance Unit, Louvain Drug Research Institute, Universite catholique de Louvain, Avenue Mounier 73.40, B-1200 Brussels (Belgium)

2010-10-15T23:59:59.000Z

123

Fourier Accelerated Conjugate Gradient Lattice Gauge Fixing  

E-Print Network [OSTI]

We provide details of the first implementation of a non-linear conjugate gradient method for Landau and Coulomb gauge fixing with Fourier acceleration. We find clear improvement over the Fourier accelerated steepest descent method, with the average time taken for the algorithm to converge to a fixed, high accuracy, being reduced by a factor of 2 to 4.

R. J. Hudspith

2014-05-22T23:59:59.000Z

124

Energy in density gradient  

E-Print Network [OSTI]

Inhomogeneous plasmas and fluids contain energy stored in inhomogeneity and they naturally tend to relax into lower energy states by developing instabilities or by diffusion. But the actual amount of energy in such inhomogeneities has remained unknown. In the present work the amount of energy stored in a density gradient is calculated for several specific density profiles in a cylindric configuration. This is of practical importance for drift wave instability in various plasmas, and in particular in its application in models dealing with the heating of solar corona because the instability is accompanied with stochastic heating, so the energy contained in inhomogeneity is effectively transformed into heat. It is shown that even for a rather moderate increase of the density at the axis in magnetic structures in the corona by a factor 1.5 or 3, the amount of excess energy per unit volume stored in such a density gradient becomes several orders of magnitude greater than the amount of total energy losses per unit ...

Vranjes, J

2015-01-01T23:59:59.000Z

125

Thermal Gradient Holes | Open Energy Information  

Open Energy Info (EERE)

Thermal Gradient Holes Thermal Gradient Holes Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Thermal Gradient Holes Details Activities (50) Areas (39) Regions (4) NEPA(29) Exploration Technique Information Exploration Group: Drilling Techniques Exploration Sub Group: Exploration Drilling Parent Exploration Technique: Exploration Drilling Information Provided by Technique Lithology: Stratigraphic/Structural: Hydrological: Field wide fluid flow characteristics if an array of wells are drilled Thermal: Mapping and projecting thermal anomalies Cost Information Low-End Estimate (USD): 5.00500 centUSD 0.005 kUSD 5.0e-6 MUSD 5.0e-9 TUSD / foot Median Estimate (USD): 16.501,650 centUSD 0.0165 kUSD 1.65e-5 MUSD 1.65e-8 TUSD / foot High-End Estimate (USD): 50.005,000 centUSD

126

Joining of Tungsten Armor Using Functional Gradients  

SciTech Connect (OSTI)

The joining of low thermal expansion armor materials such as tungsten to high thermal expansion heat sink materials has been a major problem in plasma facing component (PFC) development. Conventional planar bonding techniques have been unable to withstand the high thermal induced stresses resulting from fabrication and high heat flux testing. During this investigation, innovative functional gradient joints produced using vacuum plasma spray forming techniques have been developed for joining tungsten armor to copper alloy heat sinks. A model was developed to select the optimum gradient architecture. Based on the modeling effort, a 2mm copper rich gradient was selected. Vacuum plasma pray parameters and procedures were then developed to produce the functional gradient joint. Using these techniques, dual cooling channel, medium scale mockups (32mm wide x 400mm length) were produced with vacuum plasma spray formed tungsten armor. The thickness of the tungsten armor was up to 5mm thick. No evidence of debonding at the interface between the heat sink and the vacuum plasma sprayed material was observed.

John Scott O'Dell

2006-12-31T23:59:59.000Z

127

Gradient Resources | Open Energy Information  

Open Energy Info (EERE)

Resources Resources Jump to: navigation, search Logo: Gradient Resources Name Gradient Resources Address 9670 Gateway Drive, Suite 200 Place Reno, Nevada Zip 89521 Sector Geothermal energy Year founded 1991 Company Type For Profit Phone number (775) 284-8842 Website http://www.gradient.com/ Region Rockies Area References Gradient Resources Website[1] LinkedIn Connections CrunchBase Profile No CrunchBase profile. Create one now! Gradient Resources is a company based in Reno, Nevada. Gradient Resources is engaged in the exploration and development of geothermal resources as well as the construction, ownership and operation of geothermal power plants. The Company is headquartered in Reno, Nevada with a regional office, drilling operations center, and well-cementing

128

Hierarchically deflated conjugate gradient  

E-Print Network [OSTI]

We present a multi-level algorithm for the solution of five dimensional chiral fermion formulations, including domain wall and Mobius Fermions. The algorithm operates on the red-black preconditioned Hermitian operator, and directly accelerates conjugate gradients on the normal equations. The coarse grid representation of this matrix is next-to-next-to-next-to-nearest neighbour and multiple algorithmic advances are introduced, which help minimise the overhead of the coarse grid. The treatment of the coarse grids is purely four dimensional, and the bulk of the coarse grid operations are nearest neighbour. The intrinsic cost of most of the coarse grid operations is therefore comparable to those for the Wilson case. We also document the implementation of this algorithm in the BAGEL/Bfm software package and report on the measured performance gains the algorithm brings to simulations at the physical point on IBM BlueGene/Q hardware.

P A Boyle

2014-02-11T23:59:59.000Z

129

Gradient Sliding for Composite Optimization  

E-Print Network [OSTI]

Noname manuscript No. (will be inserted by the editor). Gradient Sliding for Composite Optimization. Guanghui Lan the date of receipt and acceptance should...

2014-06-11T23:59:59.000Z

130

The Argonne Zero Gradient Synchrotron (ZGS)  

Science Journals Connector (OSTI)

A 12.5 billion electron volt (BeV) particle accelerator the Zero Gradient Synchrotron was constructed and put into operation at the Argonne National Laboratory in August 1963. The ZGS will form the center for high energy physics research in the Midwestern part of this country. In this paper a brief description of the ZGS is given together with a discussion of the aims methods and equipment of experimental high energy physics research.

L. C. Teng

1964-01-01T23:59:59.000Z

131

VOLUME 82, NUMBER 6 P H Y S I C A L R E V I E W L E T T E R S 8 FEBRUARY 1999 Multimode Analysis of the Hollow Plasma Channel Wakefield Accelerator  

E-Print Network [OSTI]

. Two schemes of plasma excitation have been the focus of much of the work: the laser wakefield of the Hollow Plasma Channel Wakefield Accelerator C. B. Schroeder,1 D. H. Whittum,2 and J. S. Wurtele1,3 1 Berkeley National Laboratory, Berkeley, California 94720 (Received 1 April 1998) The hollow plasma channel

Wurtele, Jonathan

132

ONE GEV BEAM ACCELERATION IN A ONE METER LONG  

E-Print Network [OSTI]

ONE GEV BEAM ACCELERATION IN A ONE METER LONG PLASMA CELL A Proposal to the Stanford Linear. A single SLC bunch is used to both induce wakefields in the one meter long plasma and to witness that are needed to apply high-gradient plasma wakefield acceleration to large scale accelerators. The one meter

133

Adaptive Restart for Accelerated Gradient Schemes Brendan O'Donoghue Emmanuel Cand`es  

E-Print Network [OSTI]

Adaptive Restart for Accelerated Gradient Schemes Brendan O'Donoghue Emmanuel Cand`es April 13- matically improve the convergence rate of accelerated gradient schemes. The analysis of the technique relies. In what we refer to as the `high momentum' regime the iterates generated by an accelerated gradient scheme

Candes, Emmanuel J.

134

Correlated Knowledge Gradients: Example alternatives  

E-Print Network [OSTI]

Correlated Knowledge Gradients: Example -4 -2 0 2 4 alternatives value 0 10 20 30 -10 -8 -6 -4 -2 0;Correlated Knowledge Gradients: Example -4 -2 0 2 4 alternatives value 0 10 20 30 -10 -8 -6 -4 -2 0 num measurements log(KGfactor) 0 10 20 30 0 0.5 1 1.5 2 num measurements opportunitycost #12;Correlated Knowledge

Keinan, Alon

135

New High Energy Gradient Concentration Cathode Material  

Broader source: Energy.gov [DOE]

2011 DOE Hydrogen and Fuel Cells Program, and Vehicle Technologies Program Annual Merit Review and Peer Evaluation

136

New High Energy Gradient Concentration Cathode Material  

Broader source: Energy.gov [DOE]

2010 DOE Vehicle Technologies and Hydrogen Programs Annual Merit Review and Peer Evaluation Meeting, June 7-11, 2010 -- Washington D.C.

137

New High Energy Gradient Concentration Cathode Material  

Broader source: Energy.gov [DOE]

2012 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting

138

Osteochondral Interface Tissue Engineering using Macroscopic Gradients of Physicochemical Signals  

E-Print Network [OSTI]

of tissue interfaces. Yet, just because tissues are separated from one another by type, function, location, or anatomical prevalence, does not necessarily mean that the interfaces are as easily distinguishable, as the interfaces themselves are highly complex... not yield a true continuous gradient, it can have many discrete advantages over continuous gradients. Because of the inherent discontinuous fabrication methods (developing sections separately and fusing together), however, design effort must be placed...

Dormer, Nathan Henry

2011-04-25T23:59:59.000Z

139

PNL-SA-22914 Presented at the 48th Meeting of the Mechanical Failures Prevention Group (MFPG 48) 19-21 April 1994 in Wakefield, MA  

E-Print Network [OSTI]

-21 April 1994 in Wakefield, MA AN ARTIFICIAL NEURAL NETWORK SYSTEM FOR DIAGNOSING GAS TURBINE ENGINE FUEL Laboratory are developing a turbine engine diagnostic system for the M1A1 Abrams tank. This system employs Artificial Neural Network (ANN) technology to perform diagnosis and prognosis of the tank's AGT-1500 gas

140

Shielding effect and wakefield pattern of a moving test charge in a non-Maxwellian dusty plasma  

SciTech Connect (OSTI)

By using the Vlasov-Poisson equations, we calculate an expression for the electrostatic potential caused by a test charge in an unmagnetized non-Maxwellian dusty plasma, whose constituents are the superthermal hot-electrons, the mobile cold-electrons with a neutralizing background of cold ions, and charge fluctuating isolated dust grains. The superthermality effects due to hot electrons not only modify the dielectric constant of the electron-acoustic waves but also significantly affect the electrostatic potential. The latter can be decomposed into the Debye-Hckel and oscillatory wake potentials. Analytical and numerical results reveal that the Debye-Hckel and wakefield potentials converge to the Maxwellian case for large values of superthermality parameter. Furthermore, the plasma parameters play a vital role in the formation of shielding and wakefield pattern in a two-electron temperature plasma. The present results should be important for laboratory and space dusty plasmas, where hot-electrons can be assumed to follow the non-Maxwellian distribution function.

Ali, S. [National Centre for Physics (NCP), Quaid-e-Azam University Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan)] [National Centre for Physics (NCP), Quaid-e-Azam University Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan); Khan, S. [National Centre for Physics (NCP), Quaid-e-Azam University Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan) [National Centre for Physics (NCP), Quaid-e-Azam University Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan); Department of Physics, Gomal University, Dera Ismail Khan 29050 (Pakistan)

2013-07-15T23:59:59.000Z

Note: This page contains sample records for the topic "high gradient wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Gas Exchange, Partial Pressure Gradients,  

E-Print Network [OSTI]

Gas Exchange, Partial Pressure Gradients, and the Oxygen Window Johnny E. Brian, Jr., M of circulatory and gas transport physiology, and the best place to start is with normobaric physiology. LIFE affect the precise gas exchange occurring in individual areas of the lungs and body tissues. To make

Riba Sagarra, Jaume

142

Salinity Gradient Energy at River Mouths  

Science Journals Connector (OSTI)

Salinity Gradient Energy at River Mouths ... River mouths are potentially abundant locations for the exploitation of the clean and renewable salinity gradient energy (SGE) as here perpetually fresh water mixes with saline seawater. ...

Oscar Alvarez-Silva; Christian Winter; Andres F. Osorio

2014-09-03T23:59:59.000Z

143

Revisiting an Old Concept: The Gradient Wind  

Science Journals Connector (OSTI)

The gradient wind is defined as a horizontal wind having the same direction as the geostrophic wind but with a magnitude consistent with a balance of three forces: the pressure gradient force, the Coriolis force, and the centrifugal force arising ...

Keith F. Brill

2014-04-01T23:59:59.000Z

144

Bayesian Policy Gradient and Actor-Critic Algorithms Bayesian Policy Gradient and Actor-Critic Algorithms  

E-Print Network [OSTI]

Bayesian Policy Gradient and Actor-Critic Algorithms Bayesian Policy Gradient and Actor Yaakov Engel yakiengel@gmail.com Editor: Abstract Policy gradient methods are reinforcement learning algorithms that adapt a param- eterized policy by following a performance gradient estimate. Many

Paris-Sud XI, Université de

145

Optimization of synchronization in gradient clustered networks  

E-Print Network [OSTI]

We consider complex clustered networks with a gradient structure, where sizes of the clusters are distributed unevenly. Such networks describe more closely actual networks in biophysical systems and in technological applications than previous models. Theoretical analysis predicts that the network synchronizability can be optimized by the strength of the gradient field but only when the gradient field points from large to small clusters. A remarkable finding is that, if the gradient field is sufficiently strong, synchronizability of the network is mainly determined by the properties of the subnetworks in the two largest clusters. These results are verified by numerical eigenvalue analysis and by direct simulation of synchronization dynamics on coupled-oscillator networks.

Xingang Wang; Liang Huang; Ying-Cheng Lai; Choy Heng Lai

2007-11-23T23:59:59.000Z

146

Optimization Online - An Accelerated Proximal Coordinate Gradient ...  

E-Print Network [OSTI]

Jul 7, 2014 ... An Accelerated Proximal Coordinate Gradient Method and its Application to Regularized Empirical Risk Minimization. Qihang Lin(qihang-lin...

Qihang Lin

2014-07-07T23:59:59.000Z

147

Gradient instabilities of electromagnetic waves in Hall thruster plasma  

SciTech Connect (OSTI)

This paper presents a linear analysis of gradient plasma instabilities in Hall thrusters. The study obtains and analyzes the dispersion equation of high-frequency electromagnetic waves based on the two-fluid model of a cold plasma. The regions of parameters corresponding to unstable high frequency modes are determined and the dependence of the increments and intrinsic frequencies on plasma parameters is obtained. The obtained results agree with those of previously published studies.

Tomilin, Dmitry [Department of Electrophysics, Keldysh Research Centre, Moscow 125438 (Russian Federation)

2013-04-15T23:59:59.000Z

148

Microinstabilities in weak density gradient tokamak systems  

SciTech Connect (OSTI)

A prominent characteristic of auxiliary-heated tokamak discharges which exhibit improved (''H-mode type'') confinement properties is that their density profiles tend to be much flatter over most of the plasma radius. Depsite this favorable trend, it is emphasized here that, even in the limit of zero density gradient, low-frequency microinstabilities can persist due to the nonzero temperature gradient.

Tang, W.M.; Rewoldt, G.; Chen, L.

1986-04-01T23:59:59.000Z

149

Chapter 5 Salinity Gradient Energy  

Science Journals Connector (OSTI)

There exists a huge potential for the generation of energy from the mixing of saltwater and freshwater. The potential is 2.6TW, which is more than the global electricity consumption (2.0TW). Two membrane-based technologies exist to convert this potentially available energy into useful power: pressure-retarded osmosis (PRO) and reverse electrodialysis (RED). In PRO, water is transported through a semipermeable membrane from the less concentrated solution toward the concentrated salt solution to generate power. In RED, salt ions are transported from the concentrated salt solution through ion exchange membranes toward the less concentrated solution to extract the energy. Both technologies were developed in the 1970s and 1980s and both regained interest lately due to recent developments in membrane technology and the need for sustainable energy processes. This chapter describes the potential of salinity gradient energy of both processes in detail, and an overview of the relevant literature on both technologies is presented. Furthermore, it summarizes the recent developments, pilot testing, scale-up, and future expectations of both technologies.

Kitty Nijmeijer; Sybrand Metz

2010-01-01T23:59:59.000Z

150

Transition from Planktonic to Benthic Algal Dominance Along a Salinity Gradient  

Science Journals Connector (OSTI)

Highly regulated salinity gradients in solar salt pond concentrating sequences provide...in situ salinity impacts on aquatic flora and fauna. The ... at Useless Inlet in Western Australia vary in salinity from se...

Richard D. Segal; Anya M. Waite; David P. Hamilton

2006-02-01T23:59:59.000Z

151

Systematic Optimization of Long Gradient Chromatography Mass Spectrometry for Deep Analysis of Brain Proteome  

Science Journals Connector (OSTI)

The development of high-resolution liquid chromatography (LC) is essential for improving the sensitivity and throughput of mass spectrometry (MS)-based proteomics. Here we present systematic optimization of a long gradient LCMS/MS platform to enhance ...

Hong Wang; Yanling Yang; Yuxin Li; Bing Bai; Xusheng Wang; Haiyan Tan; Tao Liu; Thomas G. Beach; Junmin Peng; Zhiping Wu

2014-12-02T23:59:59.000Z

152

Were Archaean continental geothermal gradients much steeper than today? (reply)  

Science Journals Connector (OSTI)

... -We did not intend to suggest that our gradients bore any relationship to near-surface geothermal gradients. It may have been clearer to have termed them average ... gradients. It may have been clearer to have termed them average geothermal gradients. Our purpose in quoting these gradients was simply to emphasise that the temperature ...

KEVIN BURKE; W. S. F. KIDD

1978-08-17T23:59:59.000Z

153

Measurement of thermodynamics using gradient flow  

E-Print Network [OSTI]

We analyze bulk thermodynamics and correlation functions of the energy-momentum tensor in pure Yang-Mills gauge theory using the energy-momentum tensor defined by the gradient flow and small flow time expansion. Our results on thermodynamic observables are consistent with those obtained by the conventional integral method. The analysis of the correlation function of total energy supports the energy conservation. It is also addressed that these analyses with gradient flow require less statistics compared with the previous methods. All these results suggest that the energy-momentum tensor can be successfully defined and observed on the lattice with moderate numerical costs with the gradient flow.

Masakiyo Kitazawa; Masayuki Asakawa; Tetsuo Hatsuda; Takumi Iritani; Etsuko Itou; Hiroshi Suzuki

2014-12-15T23:59:59.000Z

154

Competition and the response of three plant species to a salinity gradient' N. C. KENKEL,A. L. MCILRAITH,C. A. BURCHILL,AND G. JONES  

E-Print Network [OSTI]

Competition and the response of three plant species to a salinity gradient' N. C. KENKEL,A. L. Competition and the response of three plant species to a salinity gradient. Can. J. Bot. 69: 2497-2502. Three-tolerant species toward the high end of the salinity gradient. The species distributions in our experimental

Kenkel, Norm

155

Ballistic dispersion in temperature gradient focusing  

E-Print Network [OSTI]

regime is the most familiar regime in microfluidic systems, an oft-overlooked regime is that of purely kinematic (or ballistic) dispersion. In most microfluidic systems, this dispersion regime is transient systems. Keywords: microfluidics; temperature gradient focusing; kinematic dispersion; Taylor

Santiago, Juan G.

156

Separation of carbon nanotubes in density gradients  

DOE Patents [OSTI]

The separation of single-walled carbon nanotubes (SWNTs), by chirality and/or diameter, using centrifugation of compositions of SWNTs in and surface active components in density gradient media.

Hersam, Mark C. (Evanston, IL); Stupp, Samuel I. (Chicago, IL); Arnold, Michael S. (Northbrook, IL)

2012-02-07T23:59:59.000Z

157

Separation of carbon nanotubes in density gradients  

DOE Patents [OSTI]

The separation of single-walled carbon nanotubes (SWNTs), by chirality and/or diameter, using centrifugation of compositions of SWNTs in and surface active components in density gradient media.

Hersam, Mark C. (Evanston, IL); Stupp, Samuel I. (Chicago, IL); Arnold, Michael S. (Northbrook, IL)

2010-02-16T23:59:59.000Z

158

The proximal-proximal gradient algorithm  

E-Print Network [OSTI]

Aug 23, 2013 ... to consider a proximal gradient algorithm [11] for solving (1), where one ...... Hence, in the case when ? = 1 and M is surjective so that T = MR for...

2013-08-24T23:59:59.000Z

159

Program predicts two-phase pressure gradients  

SciTech Connect (OSTI)

The calculator program discussed, ORK, was designed for the HP-41CV hand-held calculator and uses the Orkiszewski correlation for predicting 2-phase pressure gradients in vertical tubulars. Accurate predictions of pressure gradients in flowing and gas lift wells over a wide range of well conditions can be obtained with this method, which was developed based on data from 148 wells. The correlation is one of the best generalized 2-phase pressure gradient prediction methods developed to date for vertical flow. It is unique in that hold-up is derived from observed physical phenomena, and the pressure gradient is related to the geometrical distribution of the liquid and gas phase (flow regime).

Jacks, D.C.; Hill, A.D.

1983-11-18T23:59:59.000Z

160

Laser wakefield generated X-ray probe for femtosecond time-resolved measurements of ionization states of warm dense aluminum  

SciTech Connect (OSTI)

We have developed a laser wakefield generated X-ray probe to directly measure the temporal evolution of the ionization states in warm dense aluminum by means of absorption spectroscopy. As a promising alternative to the free electron excited X-ray sources, Betatron X-ray radiation, with femtosecond pulse duration, provides a new technique to diagnose femtosecond to picosecond transitions in the atomic structure. The X-ray probe system consists of an adjustable Kirkpatrick-Baez (KB) microscope for focusing the Betatron emission to a small probe spot on the sample being measured, and a flat Potassium Acid Phthalate Bragg crystal spectrometer to measure the transmitted X-ray spectrum in the region of the aluminum K-edge absorption lines. An X-ray focal spot size of around 50 ?m was achieved after reflection from the platinum-coated 10-cm-long KB microscope mirrors. Shot to shot positioning stability of the Betatron radiation was measured resulting in an rms shot to shot variation in spatial pointing on the sample of 16 ?m. The entire probe setup had a spectral resolution of ?1.5 eV, a detection bandwidth of ?24 eV, and an overall photon throughput efficiency of the order of 10{sup ?5}. Approximately 10 photons were detected by the X-ray CCD per laser shot within the spectrally resolved detection band. Thus, it is expected that hundreds of shots will be required per absorption spectrum to clearly observe the K-shell absorption features expected from the ionization states of the warm dense aluminum.

Mo, M. Z.; Chen, Z.; Tsui, Y. Y.; Fedosejevs, R. [Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 2V4 (Canada)] [Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 2V4 (Canada); Fourmaux, S.; Saraf, A.; Otani, K.; Kieffer, J. C. [INRS-EMT, Universit du Qubec, 1650 Lionel Boulet, Varennes, Qubec J3X 1S2 (Canada)] [INRS-EMT, Universit du Qubec, 1650 Lionel Boulet, Varennes, Qubec J3X 1S2 (Canada); Ng, A. [Department of Physics and Astronomy, University of British Columbia, British Columbia V6T 1Z1 (Canada)] [Department of Physics and Astronomy, University of British Columbia, British Columbia V6T 1Z1 (Canada)

2013-12-15T23:59:59.000Z

Note: This page contains sample records for the topic "high gradient wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Category:Thermal Gradient Holes | Open Energy Information  

Open Energy Info (EERE)

in category "Thermal Gradient Holes" This category contains only the following page. T Thermal Gradient Holes Retrieved from "http:en.openei.orgwindex.php?titleCategory:T...

162

Suppression of Zeeman gradients by nuclear polarization in double quantum dots  

E-Print Network [OSTI]

We use electric dipole spin resonance to measure dynamic nuclear polarization in InAs nanowire quantum dots. The resonance shifts in frequency when the system transitions between metastable high and low current states, indicating the presence of nuclear polarization. We propose that the low and the high current states correspond to different total Zeeman energy gradients between the two quantum dots. In the low current state, dynamic nuclear polarization efficiently compensates the Zeeman gradient due to the $g$-factor mismatch, resulting in a suppressed total Zeeman gradient. We present a theoretical model of electron-nuclear feedback that demonstrates a fixed point in nuclear polarization for nearly equal Zeeman splittings in the two dots and predicts a narrowed hyperfine gradient distribution.

S. M. Frolov; J. Danon; S. Nadj-Perge; K. Zuo; J. W. W. van Tilburg; V. S. Pribiag; J. W. G. van den Berg; E. P. A. M. Bakkers; L. P. Kouwenhoven

2012-09-07T23:59:59.000Z

163

Generation of Monolayer Gradients in Surface Energy and Surface Chemistry for Block Copolymer Thin Film Studies  

Science Journals Connector (OSTI)

Gradients in surface energy/chemistry enable high-throughput studies because a continuous range of surface energies/chemistries can be explored on a single surface, enabling faster screening and discovery of materials and phenomena. ... Furthermore, these gradients are susceptible to degradation, having a shelf life of only a few days under atmospheric conditions or a few weeks when stored in a cool, dark desiccator. ... For example, gradients could be created with a relatively narrow surface energy range (?6 mJ/m2 in this work) for high-resolution examination of morphology changes in polymer films, or gradients with a larger surface energy range could be created for a broader survey, simply by changing the chlorosilane functionalities. ...

Julie N. L. Albert; Michael J. Baney; Christopher M. Stafford; Jennifer Y. Kelly; Thomas H. Epps; III

2009-12-01T23:59:59.000Z

164

Principal processes within the estuarine salinity gradient: A review  

Science Journals Connector (OSTI)

The salinity gradient is one of the main features characteristic of any estuarine ecosystem. Within this gradient in a critical salinity range of 58 PSU the major biotic and abiotic processes demonstrate non-linear dynamics of change in rates and directions. In estuaries, this salinity range acts as both external ecological factor and physiological characteristics of internal environment of aquatic organisms; it divides living conditions appropriate for freshwater and marine faunas, separates invertebrate communities with different osmotic regulation types, and defines the distribution range of high taxa. In this paper, the non-linearity of biotic processes within the estuarine salinity gradient is illustrated by the data on zooplankton from the Baltic estuaries. The non-tidal Baltic Sea provides a good demonstration of the above phenomena due to gradual changes of environmental factors and relatively stable isohalines. The non-linearity concept coupled with the ecosystem approach served the basis for a new definition of an estuary proposed by the authors.

Irena V. Telesh; Vladislav V. Khlebovich

2010-01-01T23:59:59.000Z

165

DOE Review  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Review 2007 Review 2007 AWA Facility Update, High Gradient Wakefield Generation, and Future Upgrades Manoel Conde, Sergey Antipov, Felipe Franchini, Wei Gai, Feng Gao, Chunguang Jing, Richard Konecny, Wanming Liu, Jidong Long, John Power, Haitao Wang, Zikri Yusof Argonne Wakefield Accelerator Group High Energy Physics Division April 25 - 27, 2007 2 Outline Description of AWA Facililty. Wakefield structures built and tested. Measurements and simulations. List of next experiments to be performed. Plans for Facility upgrades. 3 AWA Drive Beamline Drive Gun Linac & Steering Coils Quads Wakefield Structure Experimental Chambers 4.5 m GV GV YAG1 YAG2 Spectrometer YAG5 Dump/ Faraday Cup Slits YAG4 YAG3 ICT1 ICT2 BPM Single bunch operation - Q=1-100 nC - Energy=15 MeV - High Current = 10 kAmp

166

Steep Gradient Flume | Open Energy Information  

Open Energy Info (EERE)

Steep Gradient Flume Steep Gradient Flume Jump to: navigation, search Basic Specifications Facility Name Steep Gradient Flume Overseeing Organization University of Iowa Hydrodynamic Testing Facility Type Flume Length(m) 20.1 Beam(m) 0.9 Depth(m) 0.5 Cost(per day) Contact POC Special Physical Features Tilting flume from -1.5 to +16% slope; <3mm sedimentation recirculation capabilities; instrumentation rails Towing Capabilities Towing Capabilities None Wavemaking Capabilities Wavemaking Capabilities None Channel/Tunnel/Flume Channel/Tunnel/Flume Yes Recirculating Yes Wind Capabilities Wind Capabilities None Control and Data Acquisition Cameras Yes Number of Color Cameras 1 Available Sensors Acoustics, Flow, Thermal, Turbulence, Velocity Data Generation Capability Real-Time Yes

167

Formation of morphogen gradients: Local accumulation time  

Science Journals Connector (OSTI)

Spatial regulation of cell differentiation in embryos can be provided by morphogen gradients, which are defined as the concentration fields of molecules that control gene expression. For example, a cell can use its surface receptors to measure the local concentration of an extracellular ligand and convert this information into a corresponding change in its transcriptional state. We characterize the time needed to establish a steady-state gradient in problems with diffusion and degradation of locally produced chemical signals. A relaxation function is introduced to describe how the morphogen concentration profile approaches its steady state. This function is used to obtain a local accumulation time that provides a time scale that characterizes relaxation to steady state at an arbitrary position within the patterned field. To illustrate the approach we derive local accumulation times for a number of commonly used models of morphogen gradient formation.

Alexander M. Berezhkovskii; Christine Sample; Stanislav Y. Shvartsman

2011-05-06T23:59:59.000Z

168

Photopolymerization in Microfluidic Gradient Generators: Microscale  

E-Print Network [OSTI]

-compliance profiles that are tunable on the micro- scale. The most straightforward way to create substrates with vari through the development of microfluidic networks,[7,8] with which one can easily generate solution (e microscale gradients with microfluidic networks, and a recent study that demon- strated

169

Porting the NAS-NPB Conjugate Gradient  

E-Print Network [OSTI]

Porting the NAS-NPB Conjugate Gradient Benchmark to CUDA NVIDIA Corporation #12;Outline ! Overview of CG benchmark ! Overview of CUDA Libraries ! CUSPARSE ! CUBLAS ! Porting Sequence ! Algorithm Analysis ! Data/Code Analysis This porting approach uses CUDA Libraries exclusively. (We will not write

Crawford, T. Daniel

170

Gradient zone-boundary control in salt-gradient solar ponds  

DOE Patents [OSTI]

A method and apparatus for suppressing zone boundary migration in a salt gradient solar pond includes extending perforated membranes across the pond at the boundaries, between the convective and non-convective zones, the perforations being small enough in size to prevent individual turbulence disturbances from penetrating the hole, but being large enough to allow easy molecular diffusion of salt thereby preventing the formation of convective zones in the gradient layer. The total area of the perforations is a sizeable fraction of the membrane area to allow sufficient salt diffusion while preventing turbulent entrainment into the gradient zone.

Hull, J.R.

1982-09-29T23:59:59.000Z

171

MeV-Energy X Rays from Inverse Compton Scattering with Laser-Wakefield Accelerated Electrons  

Science Journals Connector (OSTI)

We report the generation of MeV x rays using an undulator and accelerator that are both driven by the same 100-terawatt laser system. The laser pulse driving the accelerator and the scattering laser pulse are independently optimized to generate a high energy electron beam (>200??MeV) and maximize the output x-ray brightness. The total x-ray photon number was measured to be ?1107, the source size was 5???m, and the beam divergence angle was ?10??mrad. The x-ray photon energy, peaked at 1MeV (reaching up to 4MeV), exceeds the thresholds of fundamental nuclear processes (e.g., pair production and photodisintegration).

S. Chen; N. D. Powers; I. Ghebregziabher; C. M. Maharjan; C. Liu; G. Golovin; S. Banerjee; J. Zhang; N. Cunningham; A. Moorti; S. Clarke; S. Pozzi; D. P. Umstadter

2013-04-10T23:59:59.000Z

172

The gradient flow running coupling with twisted boundary conditions  

E-Print Network [OSTI]

We study the gradient flow for Yang-Mills theories with twisted boundary conditions. The perturbative behavior of the energy density $\\langle E(t)\\rangle$ is used to define a running coupling at a scale given by the linear size of the finite volume box. We compute the non-perturbative running of the pure gauge $SU(2)$ coupling constant and conclude that the technique is well suited for further applications due to the relatively mild cutoff effects of the step scaling function and the high numerical precision that can be achieved in lattice simulations. We also comment on the inclusion of matter fields.

A. Ramos

2014-09-04T23:59:59.000Z

173

Generation of 500 MeV-1 GeV energy electrons from laser wakefield acceleration via ionization induced injection using CO{sub 2} mixed in He  

SciTech Connect (OSTI)

Laser wakefield acceleration of 500 MeV to 1 GeV electron bunches has been demonstrated using ionization injection in mixtures of 4% to 10% of CO{sub 2} in He. 80 TW laser pulses were propagated through 5 mm gas jet targets at electron densities of 0.4-1.5 Multiplication-Sign 10{sup 19}cm{sup -3}. Ionization injection led to lower density thresholds, a higher total electron charge, and an increased probability of producing electrons above 500 MeV in energy compared to self-injection in He gas alone. Electrons with GeV energies were also observed on a few shots and indicative of an additional energy enhancement mechanism.

Mo, M. Z.; Ali, A.; Fedosejevs, R. [Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 2V4 (Canada)] [Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 2V4 (Canada); Fourmaux, S.; Lassonde, P.; Kieffer, J. C. [INRS-EMT, Universite du Quebec, 1650 Lionel Boulet, Varennes, Quebec J3X 1S2 (Canada)] [INRS-EMT, Universite du Quebec, 1650 Lionel Boulet, Varennes, Quebec J3X 1S2 (Canada)

2013-04-01T23:59:59.000Z

174

Calculation of the Electron Velocity Distribution Function in a Plasma Slab with Large Temperature and Density Gradients  

Science Journals Connector (OSTI)

...velocity. The distribution function for the...calculate the distribution function as a...region of the quiet Sun using several data-sets for temperature and density gradients...high-velocity tail of the distribution function. The...

1990-01-01T23:59:59.000Z

175

Electron profile stiffness and critical gradient studies  

SciTech Connect (OSTI)

Electron profile stiffness was studied in DIII-D L-mode discharges by systematically varying the heat flux in a narrow region with electron cyclotron heating and measuring the local change produced in {nabla}T{sub e}. Electron stiffness was found to slowly increase with toroidal rotation velocity. A critical inverse temperature gradient scale length 1/L{sub C} {approx} 3 m{sup -1} was identified at {rho}=0.6 and found to be independent of rotation. Both the heat pulse diffusivity and the power balance diffusivity, the latter determined by integrating the measured dependence of the heat pulse diffusivity on -{nabla}T{sub e}, were fit reasonably well by a model containing a critical inverse temperature gradient scale length and varying linearly with 1/L{sub T} above the threshold.

DeBoo, J. C.; Petty, C. C.; Burrell, K. H.; Smith, S. P. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); White, A. E. [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Doyle, E. J.; Hillesheim, J. C.; Rhodes, T. L.; Schmitz, L.; Wang, G.; Zeng, L. [University of California-Los Angeles, Los Angeles, California 90095-7099 (United States); Holland, C. [University of California-San Diego, La Jolla, California 92093-0417 (United States); McKee, G. R. [University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)

2012-08-15T23:59:59.000Z

176

Automated apparatus for producing gradient gels  

DOE Patents [OSTI]

Apparatus for producing a gradient gel which serves as a standard medium for a two-dimensional analysis of proteins, the gel having a density gradient along its height formed by a variation in gel composition, with the apparatus including first and second pumping means each including a plurality of pumps on a common shaft and driven by a stepping motor capable of providing small incremental changes in pump outputs for the gel ingredients, the motors being controlled, by digital signals from a digital computer, a hollow form or cassette for receiving the gel composition, means for transferring the gel composition including a filler tube extending near the bottom of the cassette, adjustable horizontal and vertical arms for automatically removing and relocating the filler tube in the next cassette, and a digital computer programmed to automatically control the stepping motors, arm movements, and associated sensing operations involving the filling operation.

Anderson, Norman L. (Clarendon Hills, IL)

1986-01-01T23:59:59.000Z

177

The Boussinesq Problem in Dipolar Gradient Elasticity  

E-Print Network [OSTI]

The three-dimensional axisymmetric Boussinesq problem of an isotropic half-space subjected to a concentrated normal quasi-static load is studied within the framework of linear dipolar gradient elasticity. Our main concern is to determine possible deviations from the predictions of classical linear elastostatics when a more refined theory is employed to attack the problem. Of special importance is the behavior of the new solution near to the point of application of the load where pathological singularities exist in the classical solution. The use of the theory of gradient elasticity is intended here to model the response of materials with microstructure in a manner that the classical theory cannot afford. A linear version of this theory results by considering a linear isotropic expression for the strain-energy density that depends on strain-gradient terms, in addition to the standard strain terms appearing in classical elasticity. Through this formulation, a microstructural material constant is introduced, in addition to the standard Lam\\'e constants. The solution method is based on integral transforms and is exact. The present results show significant departure from the predictions of classical elasticity. Indeed, continuous and bounded displacements are predicted at the points of application of the concentrated load. Such a behavior of the displacement field is, of course, more natural than the singular behavior exhibited in the classical solution.

H. G. Georgiadis; P. A. Gourgiotis; D. S. Anagnostou

2014-03-31T23:59:59.000Z

178

FIRST MEASUREMENT OF PRESSURE GRADIENT-DRIVEN CURRENTS IN TOKAMAK EDGE PLASMAS  

SciTech Connect (OSTI)

Localized currents driven by pressure gradients play a pivotal role in the magnetohydrodynamic stability of toroidal plasma confinement devices. We have measured the currents generated in the edge of L- (low) and H- (high confinement) mode discharges on the DIII-D tokamak, utilizing the Zeeman effect in an injected lithium beam to obtain high resolution profiles of the poloidal magnetic field. We find current densities in excess of 1 MA/m{sup 2} in a 1 to 2 cm region near the peak of the edge pressure gradient. These values are sufficient to challenge edge stability theories based on specific current formation models.

THOMAS DM; LEONARD AW; LAO LL; OSBORNE TH; MUELLER HW; FINKENTHAL DK

2003-11-01T23:59:59.000Z

179

Illinois: High-Energy, Concentration-Gradient Cathode Material...  

Office of Environmental Management (EM)

friendly highway transportation technologies that will enable America to use less petroleum. These technologies will provide Americans with greater freedom of mobility and...

180

Developing new high energy gradient concentration cathode material  

Broader source: Energy.gov [DOE]

2009 DOE Hydrogen Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting, May 18-22, 2009 -- Washington D.C.

Note: This page contains sample records for the topic "high gradient wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Fast global convergence of gradient methods for high-dimensional ...  

E-Print Network [OSTI]

trix recovery using nuclear norm regularization; and matrix decomposition. Overall, our analy- sis reveals interesting connections between statistical precision...

2012-08-24T23:59:59.000Z

182

Gradient-based Methods for Production Optimization of Oil Reservoirs  

E-Print Network [OSTI]

Gradient-based Methods for Production Optimization of Oil Reservoirs Eka Suwartadi Doctoral Thesis oil reservoirs. Gradient- based optimization, which utilizes adjoint-based gradient computation optimization for water flooding in the secondary phase of oil recovery is the main topic in this thesis

Foss, Bjarne A.

183

Low Impedance Bellows for High-current Beam Operations  

SciTech Connect (OSTI)

In particle accelerators, bellows are commonly used to connect beamline components. Such bellows are traditionally shielded to lower the beam impedance. Excessive beam impedance can cause overheating in the bellows, especially in high beam current operation. For an SRF-based accelerator, the bellows must also be particulate free. Many designs of shielded bellows incorporate rf slides or fingers that prevent convolutions from being exposed to wakefields. Unfortunately these mechanical structures tend to generate particulates that, if left in the SRF accelerator, can migrate into superconducting cavities, the accelerator's critical components. In this paper, we describe a prototype unshielded bellows that has low beam impedance and no risk of particulate generation.

Wu, G; Nassiri, A; Waldschmidt, G J; Yang, Y; Feingold, J J; Mammosser, J D; Rimmer, R A; Wang, H; Jang, J

2012-07-01T23:59:59.000Z

184

NEW RADIAL ABUNDANCE GRADIENTS FOR NGC 628 AND NGC 2403  

SciTech Connect (OSTI)

Motivated by recent interstellar medium studies, we present high quality MMT and Gemini spectroscopic observations of H II regions in the nearby spiral galaxies NGC 628 and NGC 2403 in order to measure their chemical abundance gradients. Using long-slit and multi-object mask optical spectroscopy, we obtained measurements of the temperature sensitive auroral lines [O III] ?4363 and/or [N II] ?5755 at a strength of 4? or greater in 11 H II regions in NGC 628 and 7 regions in NGC 2403. These observations allow us, for the first time, to derive an oxygen abundance gradient in NGC 628 based solely on 'direct' oxygen abundances of H II regions: 12 + log(O/H) = (8.43 0.03) + (0.017 0.002) R{sub g} (dex kpc{sup 1}), with a dispersion in log(O/H) of ? = 0.10 dex, from 14 regions with a radial coverage of ?2-19 kpc. This is a significantly shallower slope than found by previous 'strong-line' abundance studies. In NGC 2403, we derive an oxygen abundance gradient of 12 + log(O/H) = (8.48 0.04) + (0.032 0.007) R{sub g} (dex kpc{sup 1}), with a dispersion in log(O/H) of ? = 0.07 dex, from seven H II with a radial coverage of ?1-10 kpc. Additionally, we measure the N, S, Ne, and Ar abundances. We find the N/O ratio decreases with increasing radius for the inner disk, but reaches a plateau past R{sub 25} in NGC 628. NGC 2403 also has a negative N/O gradient with radius, but we do not sample the outer disk of the galaxy past R{sub 25} and so do not see evidence for a plateau. This bi-modal pattern measured for NGC 628 indicates dominant contributions from secondary nitrogen inside of the R{sub 25} transition and dominantly primary nitrogen farther out. As expected for ?-process elements, S/O, Ne/O, and Ar/O are consistent with constant values over a range in oxygen abundance.

Berg, Danielle A.; Skillman, Evan D. [Department of Astronomy, University of Minnesota, 116 Church St. SE, Minneapolis, MN 55455 (United States); Croxall, Kevin V. [Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Marble, Andrew R. [National Solar Observatory, 950 N Cherry Avenue, Tucson, AZ 85719 (United States); Smith, J. D. [Ritter Astrophysical Observatory, University of Toledo, Toledo, OH 43606 (United States); Gordon, Karl [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Kennicutt, Robert C. Jr. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Garnett, Donald R., E-mail: berg@astro.umn.edu, E-mail: skillman@astro.umn.edu, E-mail: croxall.5@osu.edu, E-mail: amarble@nso.edu, E-mail: jd.smith@utoledo.edu, E-mail: kgordon@stsci.edu, E-mail: robk@ast.cam.ac.uk

2013-10-01T23:59:59.000Z

185

Lepidium latifolium reproductive potential and seed dispersal along salinity and moisture gradients  

E-Print Network [OSTI]

Preserve where the salinity gradient was narrow. Conversely,production along the salinity gradient between the freshdispersal along salinity and moisture gradients Samuel P.

Leininger, Samuel P.; Foin, Theodore C.

2009-01-01T23:59:59.000Z

186

2002 Macmillan Magazines Ltd Ion gradients are widely used in transmembrane signal-  

E-Print Network [OSTI]

. These gradients are established by the active transport of ions from low to high electrochemical potentials across the membrane, driven by coupling transport to an energetically favourable process, such as ATP hydrolysis by ion channels that are located in the postsynaptic membrane and activated by neurotransmitters

Alford, Simon

187

Preparation and characterization of gradient polymer films  

SciTech Connect (OSTI)

Gradient polymers are multicomponent polymers whose chemical constitution varies with depth in the sample. Although these polymers may possess unique mechanical, optical, and barrier properties they remain relatively unexplored. This work is a study of the preparation of gradient polymers by sequential exposure of films to a diffusing monomer followed by electron beam irradiation. Initial experiments involved immersion of poly(vinyl chloride) (PVC) films in styrene or n-butyl methacrylate (BMA) for various time periods followed by irradiation with 1 or 10 megarads of accelerated electrons. A significant amount of poly(n-butyl methacrylate) (PBMA) formed in PVC/BMA systems, but little polystyrene could be found in the PVC/styrene films. A second set of experiments involved immersion of PVC and polyethylene (PE) films in BMA for 20, 40, 60, and 720 minutes followed by irradiation with 10 megarads of electrons. These films were then characterized using optical microscopy, quantitative transmission Fourier transform infrared spectroscopy (FTIR), and a depth profiling procedure based on quantitative attenuated total reflection (ATR) FTIR. It was concluded that the mechanism of PBMA formation in the polyethylene films was a result of events immediately following irradiation. Atmospheric oxygen diffusing into irradiated films trapped free radicals at the film surfaces. This was followed by storage in an evacuated desiccator where unintentional exposure to BMA vapor took place. This BMA reacted with free radicals that remained within the film cores, polymerizing to PBMA.

Smith, S.C.

1987-01-01T23:59:59.000Z

188

Analysis of Bacterial Communities in Seagrass Bed Sediments by Double-Gradient Denaturing Gradient Gel Electrophoresis  

E-Print Network [OSTI]

Microbial Ecology Analysis of Bacterial Communities in Seagrass Bed Sediments by Double, including the presence or absence of vegetation, depth into sediment, and season. Double- gradient of these similarity coefficients were used to group banding patterns by depth into sediment, presence or absence

Sherman, Tim

189

Solar energy storage by salinity gradient solar pond: Pilot plant construction and gradient control  

Science Journals Connector (OSTI)

An experimental solar pond pilot plant was constructed in Solvay-Martorell, facilities, Catalonia (NE part of the Iberian Peninsula) to capture and store solar energy. The body of the pond is a cylindrical reinforced concrete tank, 3m height, 8m diameter and total area of 50m2. Salinity and thermal gradient were properly established by using the salinity distribution methodology. The gradient in the pond was maintained by feeding salt (NaCl) through a cylindrical salt charger to the bottom at a height of 80cm from the pond floor. Continuous surface washing using tap water supply maintained the salinity of the top convective layer at a low level and compensate loses by evaporation. An acidification method by addition of \\{HCl\\} at different heights was used to control the clarity of the pond. The salinity gradient was fully established on 30 September 2009 and has been maintained until the date. After winter time (February 2010), the pond warms up and the temperature increased continuously until it reached its maximum (55C) in August 2010. The salinity gradient observed great stability after one year of continuous control and maintenance and under different weather conditions.

Csar Valderrama; Oriol Gibert; Jordina Arcal; Pau Solano; Aliakbar Akbarzadeh; Enric Larrotcha; Jos Luis Cortina

2011-01-01T23:59:59.000Z

190

Finite ballooning angle effects on ion temperature gradient driven mode in gyrokinetic flux tube simulations  

SciTech Connect (OSTI)

This paper presents effects of finite ballooning angles on linear ion temperature gradient (ITG) driven mode and associated heat and momentum flux in Gyrokinetic flux tube simulation GENE. It is found that zero ballooning angle is not always the one at which the linear growth rate is maximum. The ITG mode acquires a short wavelength (SW) branch (k{sub ?}?{sub i}?>?1) when growth rates maximized over all ballooning angles are considered. However, the SW branch disappears on reducing temperature gradient showing characteristics of zero ballooning angle SWITG in case of extremely high temperature gradient. Associated heat flux is even with respect to ballooning angle and maximizes at nonzero ballooning angle while the parallel momentum flux is odd with respect to the ballooning angle.

Singh, Rameswar, E-mail: rameswar.singh@lpp.polytechnique.fr [Institute for Plasma Research, Bhat Gandhinagar, Gujarat 2382 428 (India) [Institute for Plasma Research, Bhat Gandhinagar, Gujarat 2382 428 (India); Laboratoire de Physique des Plasmas, Ecole Polytechnique, Route de Saclay, 91128 Palaiseau Cedex (France); Brunner, S. [CRPP, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland)] [CRPP, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Ganesh, R. [Institute for Plasma Research, Bhat Gandhinagar, Gujarat 2382 428 (India)] [Institute for Plasma Research, Bhat Gandhinagar, Gujarat 2382 428 (India); Jenko, F. [Max-Planck-Institut fur Plasmaphysik, EURATOM Association, D-85748 Garching (Germany)] [Max-Planck-Institut fur Plasmaphysik, EURATOM Association, D-85748 Garching (Germany)

2014-03-15T23:59:59.000Z

191

Study of electron acceleration and x-ray radiation as a function of plasma density in capillary-guided laser wakefield accelerators  

SciTech Connect (OSTI)

Laser wakefield electron acceleration in the blow-out regime and the associated betatron X-ray radiation were investigated experimentally as a function of the plasma density in a configuration where the laser is guided. Dielectric capillary tubes were employed to assist the laser keeping self-focused over a long distance by collecting the laser energy around its central focal spot. With a 40 fs, 16 TW pulsed laser, electron bunches with tens of pC charge were measured to be accelerated to an energy up to 300 MeV, accompanied by X-ray emission with a peak brightness of the order of 10{sup 21} ph/s/mm{sup 2}/mrad{sup 2}/0.1%BW. Electron trapping and acceleration were studied using the emitted X-ray beam distribution to map the acceleration process; the number of betatron oscillations performed by the electrons was inferred from the correlation between measured X-ray fluence and beam charge. A study of the stability of electron and X-ray generation suggests that the fluctuation of X-ray emission can be reduced by stabilizing the beam charge. The experimental results are in good agreement with 3D particle-in-cell (PIC) simulation.

Ju, J.; Dpp, A.; Cros, B. [Laboratoire de Physique des Gaz et des Plasmas, CNRS-Universit Paris-Sud, 91405 Orsay (France)] [Laboratoire de Physique des Gaz et des Plasmas, CNRS-Universit Paris-Sud, 91405 Orsay (France); Svensson, K.; Genoud, G.; Wojda, F.; Burza, M.; Persson, A.; Lundh, O.; Wahlstrm, C.-G. [Department of Physics, Lund University, P.O. Box 118, S-22100 Lund (Sweden)] [Department of Physics, Lund University, P.O. Box 118, S-22100 Lund (Sweden); Ferrari, H. [Consejo Nacional de Investigaciones Cientficas y Tcnicas (CONICET) and CNEA-CAB (Argentina)] [Consejo Nacional de Investigaciones Cientficas y Tcnicas (CONICET) and CNEA-CAB (Argentina)

2013-08-15T23:59:59.000Z

192

Thermal Gradient Holes At Coso Geothermal Area (1976) | Open Energy  

Open Energy Info (EERE)

Thermal Gradient Holes At Coso Geothermal Area (1976) Thermal Gradient Holes At Coso Geothermal Area (1976) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Coso Geothermal Area (1976) Exploration Activity Details Location Coso Geothermal Area Exploration Technique Thermal Gradient Holes Activity Date 1976 Usefulness useful DOE-funding Unknown Notes Temperatures have been obtained to depths up to 133 m in 22 boreholes with measurements being made at least four times in each borehole. Geothermal gradients ranged from 240C/km to 450 0C/km. References Combs, J. (1 December 1976) Heat flow determinations and implied thermal regime of the Coso geothermal area, California Retrieved from "http://en.openei.org/w/index.php?title=Thermal_Gradient_Holes_At_Coso_Geothermal_Area_(1976)&oldid=511217"

193

Photo of the Week: The Alternating Gradient Synchrotron | Department of  

Broader source: Energy.gov (indexed) [DOE]

The Alternating Gradient Synchrotron The Alternating Gradient Synchrotron Photo of the Week: The Alternating Gradient Synchrotron March 11, 2013 - 6:00pm Addthis Since 1960, the Alternating Gradient Synchrotron (AGS) has been one of the world's premiere particle accelerators, well known for the three Nobel Prizes won as a result of research performed there. The AGS name is derived from the concept of alternating gradient focusing, in which the field gradients of the accelerator's 240 magnets are successively alternated inward and outward, permitting particles to be propelled and focused in both the horizontal and vertical plane at the same time. In this 1958 photo, giant magnets await installation into the AGS accelerator ring tunnel at Brookhaven National Laboratory. | Photo courtesy of Brookhaven National Laboratory.

194

Photo of the Week: The Alternating Gradient Synchrotron | Department of  

Broader source: Energy.gov (indexed) [DOE]

The Alternating Gradient Synchrotron The Alternating Gradient Synchrotron Photo of the Week: The Alternating Gradient Synchrotron March 11, 2013 - 6:00pm Addthis Since 1960, the Alternating Gradient Synchrotron (AGS) has been one of the world's premiere particle accelerators, well known for the three Nobel Prizes won as a result of research performed there. The AGS name is derived from the concept of alternating gradient focusing, in which the field gradients of the accelerator's 240 magnets are successively alternated inward and outward, permitting particles to be propelled and focused in both the horizontal and vertical plane at the same time. In this 1958 photo, giant magnets await installation into the AGS accelerator ring tunnel at Brookhaven National Laboratory. | Photo courtesy of Brookhaven National Laboratory.

195

Temperature, heat flow maps and temperature gradient holes |...  

Open Energy Info (EERE)

Temperature, heat flow maps and temperature gradient holes Author T. G. Zacharakis Organization Colorado Geological Survey in Cooperation with the U.S. Department of Energy...

196

Ch. VII, Temperature, heat flow maps and temperature gradient...  

Open Energy Info (EERE)

Ch. VII, Temperature, heat flow maps and temperature gradient holes Author T. G. Zacharakis Editor T. G. Zacharakis Published Colorado Geological Survey in Cooperation with the...

197

A Sparsity Preserving Stochastic Gradient Method for Composite ...  

E-Print Network [OSTI]

Apr 23, 2011 ... Abstract: We propose new stochastic gradient algorithms for solving convex composite optimization problems. In each iteration, our algorithms...

Qihang Lin

2011-04-23T23:59:59.000Z

198

A Sparsity Preserving Stochastic Gradient Method for Composite ...  

E-Print Network [OSTI]

Apr 23, 2011 ... We propose new stochastic gradient algorithms for solving convex composite optimization problems. In each iteration, our algorithms utilize a...

2011-04-23T23:59:59.000Z

199

Thermal Gradient Holes At Long Valley Caldera Geothermal Area...  

Open Energy Info (EERE)

Date 1978 - 1985 Usefulness useful DOE-funding Unknown Exploration Basis Thermal gradient drilling also continued during this period, consisting of several holes including: The...

200

Thermal Gradient Holes At Chena Geothermal Area (EERE, 2010)...  

Open Energy Info (EERE)

EERE, 2010) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Chena Geothermal Area (EERE, 2010) Exploration Activity...

Note: This page contains sample records for the topic "high gradient wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Policy Gradient Methods: Variance Reduction and Stochastic Convergence .  

E-Print Network [OSTI]

??In a reinforcement learning task an agent must learn a policy for performing actions so as to perform well in a given environment. Policy gradient (more)

Greensmith, Evan

2008-01-01T23:59:59.000Z

202

Microconvection effects at double?diffusive gradient zone boundaries  

Science Journals Connector (OSTI)

Microconvection in double?diffusive gradient zones is predicted to occur near the zone boundaries because of effects of boundary undulation and temperature modulation caused by impinging thermals in adjacent convecting zones. The equations that govern convective motion in a double?diffusive horizontal slab are solved for boundary conditions that incorporate these effects. Solution of these equations predicts a weakened salinity gradient near the gradient zone boundary between the rising thermals. When the salinity gradient is too weak instability occurs taking the form of descending plumes which are seen in experiments.

John R. Hull; Yojana Katti

1988-01-01T23:59:59.000Z

203

Evapotranspiration along an elevation gradient in California's Sierra Nevada  

E-Print Network [OSTI]

Soil-moisture use by mixed conifer forest in a summer- dryforest, Sierra mixed conifer forest, and Subalpine forest)Climate Gradient Sierran Mixed Conifer Forest Sierra Climate

Goulden, M. L.; Anderson, R. G.; Bales, R. C.; Kelly, A. E.; Meadows, M.; Winston, G. C.

2012-01-01T23:59:59.000Z

204

Thermal Gradient Holes At Cove Fort Area - Vapor (Warpinski,...  

Open Energy Info (EERE)

Warpinski, Et Al., 2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Cove Fort Area - Vapor (Warpinski, Et Al.,...

205

Thermal Gradient Holes At Chena Geothermal Area (Erkan, Et Al...  

Open Energy Info (EERE)

Erkan, Et Al., 2007) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Chena Geothermal Area (Erkan, Et Al., 2007)...

206

Thermal Gradient Holes At Obsidian Cliff Area (Hulen, Et Al....  

Open Energy Info (EERE)

Obsidian Cliff Area (Hulen, Et Al., 2003) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Obsidian Cliff Area (Hulen,...

207

An inexact accelerated proximal gradient method for large scale ...  

E-Print Network [OSTI]

The accelerated proximal gradient (APG) method, first proposed by Nesterov, and later refined by Beck and Teboulle, and studied in a unifying manner by Tseng.

2011-09-09T23:59:59.000Z

208

An accelerated proximal gradient algorithm for nuclear norm ...  

E-Print Network [OSTI]

Mar 27, 2009 ... An accelerated proximal gradient algorithm for nuclear norm regularized least squares problems. Kim-Chuan Toh (mattohkc ***at*** nus.edu.sg)

Kim-Chuan Toh

2009-03-27T23:59:59.000Z

209

Thermal Gradient Holes At Glass Mountain Area (Cumming And Mackie...  

Open Energy Info (EERE)

Area (Cumming And Mackie, 2007) Exploration Activity Details Location Glass Mountain Geothermal Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness not...

210

Analysis of natural gradient descent for multilayer neural networks  

Science Journals Connector (OSTI)

Natural gradient descent is a principled method for adapting the parameters of a statistical model on-line using an underlying Riemannian parameter space to redefine the direction of steepest descent. The algorithm is examined via methods of statistical physics that accurately characterize both transient and asymptotic behavior. A solution of the learning dynamics is obtained for the case of multilayer neural network training in the limit of large input dimension. We find that natural gradient learning leads to optimal asymptotic performance and outperforms gradient descent in the transient, significantly shortening or even removing plateaus in the transient generalization performance that typically hamper gradient descent training.

Magnus Rattray and David Saad

1999-04-01T23:59:59.000Z

211

Evaluation of liquid lift approach to dual gradient  

E-Print Network [OSTI]

the mudline to the rig floor so as to maintain the bottom hole pressure. Several methods have been developed to achieve the dual gradient drilling principle. For this research project, we paid more attention to the liquid lift, dual gradient drilling (riser...

Okafor, Ugochukwu Nnamdi

2009-05-15T23:59:59.000Z

212

Evaluation of liquid lift approach to dual gradient drilling  

E-Print Network [OSTI]

the mudline to the rig floor so as to maintain the bottom hole pressure. Several methods have been developed to achieve the dual gradient drilling principle. For this research project, we paid more attention to the liquid lift, dual gradient drilling (riser...

Okafor, Ugochukwu Nnamdi

2008-10-10T23:59:59.000Z

213

Were Archaean continental geothermal gradients much steeper than today?  

Science Journals Connector (OSTI)

... km depth) did not generally exceed 800 C. From this they deduce a surface geothermal gradient of less than 23 C km'1 compared with 17 C km'1 in ... P-T determinations on Archaean granulites (summarised in ref. 2) their calculation of the geothermal gradient does not comply with conductive properties and distribution of heat producing elements within the ...

S. A. DRURY

1978-08-17T23:59:59.000Z

214

Energy Conversion from Salinity Gradients by Forward OsmosisElectrokinetics  

Science Journals Connector (OSTI)

Energy Conversion from Salinity Gradients by Forward OsmosisElectrokinetics ... Through the use of a salinity gradient, a suction force is created to induce a hydrodynamic flow in the FO submodule based on the principle of FO. ... Kiviat, F. E.Energy Recovery from Saline Water by Means of Electrochemical Cells Science 1976, 194, 719 720 ...

Yanmei Jiao; Chun Yang; Yuejun Kang

2014-03-12T23:59:59.000Z

215

Argonne Today  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Argonne logo Argonne logo Argonne Today Wednesday, June 6, 2007 Seminars Submit seminar listings to seminars@anl.gov. There are no seminars scheduled today. Thursday, June 7 High Energy Physics Division Astrophysics Luncheon: "VERITAS - History, Status and First Results" by Deirdre Horan (HEP). Noon, Building 213 Cafeteria Private Dining Room A. Science update Wakefield facility achieves acceleration milestone Scientists at the Argonne Wakefield Accelerator facility are developing advanced technologies relevant to future high-energy physics machines. Their main goal is to identify and develop acceleration methods that may lead to more efficient, compact, and inexpensive particle accelerators. The method being pursued by the Argonne group is electron beam-driven wakefield acceleration in dielectric loaded structures, where a high-charge electron beam excites a high acceleration gradient.

216

Efficient and robust gradient enhanced Kriging emulators.  

SciTech Connect (OSTI)

%E2%80%9CNaive%E2%80%9D or straight-forward Kriging implementations can often perform poorly in practice. The relevant features of the robustly accurate and efficient Kriging and Gradient Enhanced Kriging (GEK) implementations in the DAKOTA software package are detailed herein. The principal contribution is a novel, effective, and efficient approach to handle ill-conditioning of GEK's %E2%80%9Ccorrelation%E2%80%9D matrix, RN%CC%83, based on a pivoted Cholesky factorization of Kriging's (not GEK's) correlation matrix, R, which is a small sub-matrix within GEK's RN%CC%83 matrix. The approach discards sample points/equations that contribute the least %E2%80%9Cnew%E2%80%9D information to RN%CC%83. Since these points contain the least new information, they are the ones which when discarded are both the easiest to predict and provide maximum improvement of RN%CC%83's conditioning. Prior to this work, handling ill-conditioned correlation matrices was a major, perhaps the principal, unsolved challenge necessary for robust and efficient GEK emulators. Numerical results demonstrate that GEK predictions can be significantly more accurate when GEK is allowed to discard points by the presented method. Numerical results also indicate that GEK can be used to break the curse of dimensionality by exploiting inexpensive derivatives (such as those provided by automatic differentiation or adjoint techniques), smoothness in the response being modeled, and adaptive sampling. Development of a suitable adaptive sampling algorithm was beyond the scope of this work; instead adaptive sampling was approximated by omitting the cost of samples discarded by the presented pivoted Cholesky approach.

Dalbey, Keith R.

2013-08-01T23:59:59.000Z

217

Beyond-the-Standard-Model matrix elements with the gradient flow  

E-Print Network [OSTI]

At the Forschungszentrum Juelich (FZJ) we have started a long-term program that aims to determine beyond-the-Standard-Model (BSM) matrix elements using the gradient flow, and to understand the impact of BSM physics in nucleon and nuclear observables. Using the gradient flow, we propose to calculate the QCD component of key beyond the Standard Model (BSM) matrix elements related to quark and strong theta CP violation and the strange content within the nucleon. The former set of matrix elements impacts our understanding of Electric Dipole Moments (EDMs) of nucleons and nuclei (a key signature of BSM physics), while the latter contributes to elastic recoil of Dark Matter particles off nucleons and nuclei. If successful, these results will lay the foundation for extraction of BSM observables from future low-energy, high-intensity and high-accuracy experimental measurements.

A. Shindler; J. de Vries; T. Luu

2014-09-09T23:59:59.000Z

218

Beyond-the-Standard-Model matrix elements with the gradient flow  

E-Print Network [OSTI]

At the Forschungszentrum Juelich (FZJ) we have started a long-term program that aims to determine beyond-the-Standard-Model (BSM) matrix elements using the gradient flow, and to understand the impact of BSM physics in nucleon and nuclear observables. Using the gradient flow, we propose to calculate the QCD component of key beyond the Standard Model (BSM) matrix elements related to quark and strong theta CP violation and the strange content within the nucleon. The former set of matrix elements impacts our understanding of Electric Dipole Moments (EDMs) of nucleons and nuclei (a key signature of BSM physics), while the latter contributes to elastic recoil of Dark Matter particles off nucleons and nuclei. If successful, these results will lay the foundation for extraction of BSM observables from future low-energy, high-intensity and high-accuracy experimental measurements.

Shindler, A; Luu, T

2014-01-01T23:59:59.000Z

219

Determination of salinity gradient power potential in Qubec, Canada  

Science Journals Connector (OSTI)

Electrical energy can be produced from the chemical potential difference of two liquids with dissimilar salinities. This source of energy is known as salinity gradient power. In this paper the theory the technologies used to exploit the power the major challenges and their development trends are first presented. Then a modeling of fluxes across semi permeable membranes is proposed and validated. Next an energy balance study is done in order to estimate the power potential for a given salinity gradient system. By applying this study to several rivers in Quebec the salinity power gradient potential is estimated to 45 TWh/yr based on the minimal flow rate of each river.

Y. Berrouche; P. Pillay

2012-01-01T23:59:59.000Z

220

High Power Operation of the JLab IR FEL Driver Accelerator  

SciTech Connect (OSTI)

Operation of the JLab IR Upgrade FEL at CW powers in excess of 10 kW requires sustained production of high electron beam powers by the driver ERL. This in turn demands attention to numerous issues and effects, including: cathode lifetime; control of beamline and RF system vacuum during high current operation; longitudinal space charge; longitudinal and transverse matching of irregular/large volume phase space distributions; halo management; management of remnant dispersive effects; resistive wall, wake-field, and RF heating of beam vacuum chambers; the beam break up instability; the impact of coherent synchrotron radiation (both on beam quality and the performance of laser optics); magnetic component stability and reproducibility; and RF stability and reproducibility. We discuss our experience with these issues and describe the modus vivendi that has evolved during prolonged high current, high power beam and laser operation.

Kevin Beard; Stephen Benson; George Biallas; James Boyce; Donald Bullard; James Coleman; David Douglas; H. Dylla; Richard Evans; Pavel Evtushenko; Christopher Gould; Albert Grippo; Joseph Gubeli; David Hardy; Carlos Hernandez-Garcia; J. Hovater; Kevin Jordan; John Klopf; Rui Li; Steven Moore; George Neil; Benard Poelker; Thomas Powers; Joseph Preble; Robert Rimmer; Daniel Sexton; Michelle D. Shinn; Christopher Tennant; Richard Walker; Gwyn Williams; Shukui Zhang

2007-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "high gradient wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

high  

Gasoline and Diesel Fuel Update (EIA)

0 0 Summary Our short-term outlook for a wide array of energy prices has been adjusted upward as international and domestic energy supply conditions have tightened. We think that crude oil prices are as likely as not to end the year $2 to $3 per barrel higher than our previous projections. Thus, we think that the probability of West Texas Intermediate costing an average of $30 per barrel or more at midwinter is about 50 percent. On their current track, heating oil prices are likely to be about 30 percent above year-ago levels in the fourth quarter. Prices for Q1 2001 seem more likely now to match or exceed the high level seen in Q1 2000. Tight oil markets this year and an inherent propensity for high gas utilization in incremental power supply have resulted in rising North American natural gas

222

TESTING FOR AZIMUTHAL ABUNDANCE GRADIENTS IN M101  

SciTech Connect (OSTI)

New optical spectra of 28 H II regions in the M101 disk have been obtained, yielding 10 new detections of the [O III] {lambda}4363 auroral line. The oxygen abundance gradient measured from these data, combined with previous observations, displays a local scatter of 0.15 {+-} 0.03 dex along an arc in the west side of the galaxy, compared with a smaller scatter of 0.08 {+-} 0.01 dex in the rest of the disk. One of the H II regions in our sample (H27) has a significantly lower oxygen abundance than surrounding nebulae at a similar galactocentric distance, while an additional, relatively nearby one (H128) was already known to have a high oxygen abundance for its position in the galaxy. These results represent marginal evidence for the existence of moderate deviations from chemical abundance homogeneity in the interstellar medium of M101. Using a variety of strong-line abundance indicators, we find no evidence for significant large-scale azimuthal variations of the oxygen abundance across the whole disk of the galaxy.

Li, Yanxia; Bresolin, Fabio [Institute for Astronomy, 2680 Woodlawn Dr., Honolulu, HI 96822 (United States)] [Institute for Astronomy, 2680 Woodlawn Dr., Honolulu, HI 96822 (United States); Kennicutt, Robert C. Jr. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)] [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)

2013-03-20T23:59:59.000Z

223

Field Investigations And Temperature-Gradient Drilling At Marine Corps  

Open Energy Info (EERE)

Investigations And Temperature-Gradient Drilling At Marine Corps Investigations And Temperature-Gradient Drilling At Marine Corps Air-Ground Combat Center (Mcagcc), Twenty-Nine Palms, Ca Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Paper: Field Investigations And Temperature-Gradient Drilling At Marine Corps Air-Ground Combat Center (Mcagcc), Twenty-Nine Palms, Ca Details Activities (4) Areas (1) Regions (0) Abstract: The U.S. Navy's Geothermal Program Office (GPO) has been conducting geothermal exploration activities in the Camp Wilson area of Marine Corps Air-Ground Combat Center (MCAGCC), Twenty-nine Palms, CA, for almost two years. Work has included self-potential (SP) surveys, fault structure analyses using LiDAR surveys, and drilling and assessment of five (5) temperature-gradient holes. For several decades the GPO has worked

224

A gradient index sonic lens based on acoustic metamaterials  

Science Journals Connector (OSTI)

We report a method to design and characterize broadband gradient index lenses. The lenses are based on two?dimensional sonic crystals which are periodic arrangements of elastic cylinders embedded in air. It will be shown that gradient index sonic lenses built with rigid cylinders are more powerful than conventionally curved lenses. We also demonstrate that the designing possibilities increased by considering the mixture of two types of cylinders in the sonic crystal. So a gradient index lens with zero reflectance at the surface is proposed by employing a mixture of aerogel and rigid cylinders. Finally a multiple scatteringtheory has been employed to compare the performance of conventionally curved lenses and gradient index lenses. [Work supported by MEC of Spain and GVA of Valencia.

Jos Snchez?Dehesa; Daniel Torrent

2007-01-01T23:59:59.000Z

225

Potential use of hollow spheres in dual gradient drilling  

E-Print Network [OSTI]

The increasing number of significant deepwater discoveries has pushed the operator and service oil companies to focus their efforts on developing new technologies to drill in deeper water. Dual gradient drilling (DGD) will allow reaching deeper...

Vera Vera, Liliana

2012-06-07T23:59:59.000Z

226

Use of gradient magnets in low emittance electron storage rings  

SciTech Connect (OSTI)

The use of gradient magnets for a low emittance electron storage ring is discussed and a magnetic lattice for a 6 GeV electron energy synchrotron radiation source adopting this feature is presented.

Vignola, G.

1985-01-01T23:59:59.000Z

227

A three-term conjugate gradient method with sufficient descent ...  

E-Print Network [OSTI]

k?1yk?1. ,. (1.2) where yk?1 is defined by yk?1 = gk ? gk?1 and denotes the l2 ...... [15] M.R. Hestenes and E. Stiefel, Methods of conjugate gradients for solving

2009-11-02T23:59:59.000Z

228

Functionally gradient titanium-aluminide composites produced by laser cladding  

Science Journals Connector (OSTI)

The laser surface cladding of Ti-Al/TiB2...composites was investigated as a means of producing a functionally gradient material on a commercially pure Ti substrate. Single and double layers were produced. The pro...

J. H. Abboud; D. R. F. West; R. D. Rawlings

1994-07-01T23:59:59.000Z

229

A parametric study of thermomechanical behavior of functionally gradient materials  

E-Print Network [OSTI]

(FSDT) that accounts for the transverse shear strains and the rotations, coupled with a three dimensional heat conduction equation is formulated for a functionally gradient plate. Both problems are studied by varying the volume fraction of a ceramic...

Chin, Che-Doong

1996-01-01T23:59:59.000Z

230

The Hadley Circulation and the Weak Temperature Gradient Approximation  

Science Journals Connector (OSTI)

The weak temperature gradient (WTG) approximation is applied to simple shallow-water models of the Hadley circulation. While it is difficult to formally justify the use of the WTG approximation for this problem, the derived WTG solutions are ...

L. M. Polvani; A. H. Sobel

2002-05-01T23:59:59.000Z

231

Computational Inversion of Electron Tomography Images -Gradient Flows  

E-Print Network [OSTI]

Computational Inversion of Electron Tomography Images Using L2 -Gradient Flows Guoliang Xu 1) Ming Computing Institute of Computational Mathematics, Academy of Mathematics and System Sciences, Chinese Academy of Sciences, Beijing 100190, China 2) Department of Computer Sciences and Institute

Texas at Austin, University of

232

Thermal Gradient Holes At Central Nevada Seismic Zone Region (Pritchett,  

Open Energy Info (EERE)

Thermal Gradient Holes At Central Nevada Seismic Zone Region (Pritchett, Thermal Gradient Holes At Central Nevada Seismic Zone Region (Pritchett, 2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Central Nevada Seismic Zone Region (Pritchett, 2004) Exploration Activity Details Location Central Nevada Seismic Zone Geothermal Region Exploration Technique Thermal Gradient Holes Activity Date Usefulness useful DOE-funding Unknown Notes NOTE: These are theoretical/computer simulation tests of various methods on eight hypothetical 'model' basing-and-range geothermal systems. "The 300-meter heat flow holes are essentially useless for finding the "hidden" reservoirs. Clearly, the best results are obtained from the SP and MT surveys, with DC resistivity a close third. It is concluded that the best

233

Generation of Gradients Having Complex Shapes Using Microfluidic Networks  

E-Print Network [OSTI]

Generation of Gradients Having Complex Shapes Using Microfluidic Networks Stephan K. W. Dertinger, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138 This paper describes the generation each carrying different concentrations of substances laminarly and side-by-side generated step

Prentiss, Mara

234

A Tree-Ring Reconstruction of the Salinity Gradient in the Northern Estuary of San Francisco Bay  

E-Print Network [OSTI]

Ring Reconstruction of the Salinity Gradient in the Northernof the seasonal salinity gradient, or low salinity zone (the longitudinal salinity gradient in the northern estuary (

2011-01-01T23:59:59.000Z

235

Effects of interspecific competition and coastal oceanography on population dynamics of the Olympia oyster, Ostrea lurida, along estuarine gradients  

E-Print Network [OSTI]

across estuarine salinity gradients. Ecology 85:2539- Dalby,abundance along a salinity gradient. Ecology Lamb, E. G. andalong an estuarine salinity gradient. Oikos Etter, R. J.

Deck, Anna K.

2011-01-01T23:59:59.000Z

236

Salinity Gradient Power: Utilizing Vapor Pressure Differences  

Science Journals Connector (OSTI)

...high cost, degradation, polariza-tion, and solution pretreatment require-ments. In principle, however, most desa-lination schemes that are reversible are capable of producing power in salina-tion. The scheme we report here does not require...

MARK OLSSON; GERALD L. WICK; JOHN D. ISAACS

1979-10-26T23:59:59.000Z

237

Ammonium Bicarbonate Transport in Anion Exchange Membranes for Salinity Gradient Energy  

Science Journals Connector (OSTI)

Ammonium Bicarbonate Transport in Anion Exchange Membranes for Salinity Gradient Energy ... Current status of ion exchange membranes for power generation from salinity gradients ...

Geoffrey M. Geise; Michael A. Hickner; Bruce E. Logan

2013-08-22T23:59:59.000Z

238

E-Print Network 3.0 - alternating gradient focusing Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

gradient focusing Page: << < 1 2 3 4 5 > >> 1 Gradient Estimation in Global Optimization Algorithms Megan Hazen, Member, IEEE and Maya R. Gupta, Member, IEEE Summary:...

239

Single molecule studies of meso/macro porous silica materials and gradient films.  

E-Print Network [OSTI]

??The preparation of mesoporous/macroporous silica materials and polarity gradient thin film are introduced in this thesis. These porous silica materials and gradient materials have the (more)

Ye, Fangmao

2009-01-01T23:59:59.000Z

240

high  

Gasoline and Diesel Fuel Update (EIA)

0 0 Highlights International Oil Markets Prices. We have raised our world oil price projection by about $2 per barrel for this month because of assumed greater compliance by OPEC to targeted cuts, especially for the second quarter of 2000 (Figure 1). The expected decline in world petroleum inventories continues (Figure 2), and, given the generally stiff resolve of OPEC members to maintain production cuts, any sign of a turnaround in stocks may be postponed until later this year than previously assumed (Q3 instead of Q2). Our current estimate for the average import cost this past January is now $25 per barrel, a nearly $15-per-barrel increase from January 1999. Crude oil prices are expected to remain at relatively high levels for the first half of 2000, but

Note: This page contains sample records for the topic "high gradient wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

GLASS: gas-phase metallicity and radial gradients in an interacting system at z~2  

E-Print Network [OSTI]

We present spatially resolved gas-phase metallicity for a system of three galaxies at z=1.85 detected in the Grism Lensed-Amplified Survey from Space (GLASS). The combination of HST's diffraction limit and strong gravitational lensing by the cluster MACS J0717+3745 results in a spatial resolution of ~200-300 pc, enabling good spatial sampling despite the intrinsically small galaxy sizes. The galaxies in this system are separated by 50-200 kpc in projection and are likely in an early stage of interaction, evidenced by relatively high specific star formation rates. Their gas-phase metallicities are consistent with larger samples at similar redshift, star formation rate, and stellar mass. We obtain a precise measurement of the metallicity gradient for one galaxy and find a shallow slope compared to isolated galaxies at high redshift, consistent with a flattening of the gradient due to gravitational interaction. An alternative explanation for the shallow metallicity gradient and elevated star formation rate is ra...

Jones, Tucker; Schmidt, Kasper; Treu, Tommaso; Brammer, Gabriel; Bradac, Marusa; Dressler, Alan; Henry, Alaina; Malkan, Matthew; Pentericci, Laura; Trenti, Michele

2014-01-01T23:59:59.000Z

242

Environmental causes for plant biodiversity gradients  

Science Journals Connector (OSTI)

...families exposed to a high energy load tend to be both more...in the Cape of South Africa, a likely product of...Phylogeny Plant Transpiration Solar Energy Temperature Ultraviolet...in the Cape of South Africa, a likely product of...

2004-01-01T23:59:59.000Z

243

A planar ion trap chip with integrated structures for an adjustable magnetic field gradient  

E-Print Network [OSTI]

field necessary for magnetic-gradient- induced coupling between ionic effective spins. We dem- onstrate] magnetic field gradient, however, such coupling is induced. Also, coupling between spin states of different-gradient- induced coupling (MAGIC). A static gradient can be generated by permanent mag- nets [15, 16] or by current

Wunderlich, Christof

244

Spatial Gradients in Particle Reinforced Polymers Characterized by X-Ray Attenuation and Laser Confocal Microscopy  

SciTech Connect (OSTI)

The goal of this work is to develop techniques for measuring gradients in particle concentration within filled polymers, such as encapsulant. A high concentration of filler particles is added to such materials to tailor physical properties such as thermal expansion coefficient. Sedimentation and flow-induced migration of particles can produce concentration gradients that are most severe near material boundaries. Therefore, techniques for measuring local particle concentration should be accurate near boundaries. Particle gradients in an alumina-filled epoxy resin are measured with a spatial resolution of 0.2 mm using an x-ray beam attenuation technique, but an artifact related to the finite diameter of the beam reduces accuracy near the specimen's edge. Local particle concentration near an edge can be measured more reliably using microscopy coupled with image analysis. This is illustrated by measuring concentration profiles of glass particles having 40 {micro}m median diameter using images acquired by a confocal laser fluorescence microscope. The mean of the measured profiles of volume fraction agrees to better than 3% with the expected value, and the shape of the profiles agrees qualitatively with simple theory for sedimentation of monodisperse particles. Extending this microscopy technique to smaller, micron-scale filler particles used in encapsulant for microelectronic devices is illustrated by measuring the local concentration of an epoxy resin containing 0.41 volume fraction of silica.

LAGASSE,ROBERT R.; THOMPSON,KYLE R.

2000-06-12T23:59:59.000Z

245

Diffraction Profiles of Elasticity Bent Single Crystals with Constant Strain Gradients  

SciTech Connect (OSTI)

This work presents a set of equations that can be used to predict the dynamical diffraction profile from a non-transparent single crystal with a constant strain gradient examined in Bragg reflection geometry with a spherical incident X-ray beam. In agreement with previous work, the present analysis predicts two peaks: a primary diffraction peak, which would have still been observed in the absence of the strain gradient and which exits the specimen surface at the intersection point of the incident beam with the sample surface, and a secondary (mirage) peak, caused by the deflection of the wavefield within the material, which exits the specimen surface further from this intersection point. The integrated intensity of the mirage peak increases with increasing strain gradient, while its separation from the primary reflection peak decreases. The directions of the rays forming the mirage peak are parallel to those forming the primary diffraction peak. However, their spatial displacement might cause (fictitious) angular shifts in diffractometers equipped with area detectors or slit optics. The analysis results are compared with experimental data from an Si single-crystal strip bent in cantilever configuration, and the implications of the mirage peak for Laue analysis and high-precision diffraction measurements are discussed.

Yan,H.; Kalenci, O.; Noyan, I.

2007-01-01T23:59:59.000Z

246

Geology and Temperature Gradient Surveys Blue Mountain Geothermal  

Open Energy Info (EERE)

Geology and Temperature Gradient Surveys Blue Mountain Geothermal Geology and Temperature Gradient Surveys Blue Mountain Geothermal Discovery, Humboldt County, Nevada Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Geology and Temperature Gradient Surveys Blue Mountain Geothermal Discovery, Humboldt County, Nevada Abstract Triassic argillite and sandstone of the Grass Valley Formation and phyllitic mudstone of the overlying Raspberry Formation, also of Triassic age, host a blind geothermal system under exploration by Blue Mountain Power Company Inc. with assistance from the Energy & Geoscience Institute. Geologically young, steeply dipping, open fault sets, striking N50-60°E,N50-60°W, and N-S intersect in the geothermal zone providing deep permeability over a wide area. Extensive silicification andhydro

247

Pumpernickel Valley Geothermal Project Thermal Gradient Wells | Open Energy  

Open Energy Info (EERE)

Valley Geothermal Project Thermal Gradient Wells Valley Geothermal Project Thermal Gradient Wells Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Report: Pumpernickel Valley Geothermal Project Thermal Gradient Wells Details Activities (4) Areas (1) Regions (0) Abstract: The Pumpernickel Valley geothermal project area is located near the eastern edge of the Sonoma Range and is positioned within the structurally complex Winnemucca fold and thrust belt of north-central Nevada. A series of approximately north-northeast-striking faults related to the Basin and Range tectonics are superimposed on the earlier structures within the project area, and are responsible for the final overall geometry and distribution of the pre-existing structural features on the property. Two of these faults, the Pumpernickel Valley fault and Edna Mountain fault,

248

Nonlinear elastic free energies and gradient Young-Gibbs measures  

E-Print Network [OSTI]

We investigate, in a fairly general setting, the limit of large volume equilibrium Gibbs measures for elasticity type Hamiltonians with clamped boundary conditions. The existence of a quasiconvex free energy, forming the large deviations rate functional, is shown using a new interpolation lemma for partition functions. The local behaviour of the Gibbs measures can be parametrized by Young measures on the space of gradient Gibbs measures. In view of unboundedness of the state space, the crucial tool here is an exponential tightness estimate that holds for a vast class of potentials and the construction of suitable compact sets of gradient Gibbs measures.

Roman Koteck; Stephan Luckhaus

2012-06-26T23:59:59.000Z

249

Speed-gradient principle for nonstationary processes in thermodynamics  

E-Print Network [OSTI]

The speed-gradient variational principle (SG-principle) is formulated and applied to thermodynamical systems. It is shown that Prigogine's principle of minimum entropy production and Onsager's symmetry relations can be interpreted in terms of the SG-principle and, therefore, are equivalent to each other. In both cases entropy of the system plays a role of the goal functional. The speed-gradient formulation of thermodynamic principles provide their extended versions, describing transient dynamics of nonstationary systems far from equilibrium. As an example a model of transient (relaxation) dynamics for maximum entropy principle is derived.

Alexander L. Fradkov

2007-01-28T23:59:59.000Z

250

Gradient-Based Distance Estimation for Spatial Computers  

Science Journals Connector (OSTI)

......the reduced width area, the average gradient value Gout avg and the SMG value Gout si are shown using Equation (12) and (13). If...Gin si as shown using Equation (14) and (15). Gout avg = nl (a - 1) + nl a + nl (a + 1) nl = a......

Qingzhi Liu; Andrei Pruteanu; Stefan Dulman

2013-12-01T23:59:59.000Z

251

Oil displacement through a porous medium with a temperature gradient  

E-Print Network [OSTI]

We investigate the effect of a temperature gradient on oil recovery in a two-dimensional pore-network model. The oil viscosity depends on temperature as, $\\mu_o=exp(B/T)$, where $B$ is a physico-chemical parameter depending on the type of oil, and $T$ is the temperature. A temperature gradient is applied across the medium in the flow direction. Initially, the porous medium is saturated with oil and, then, another fluid is injected. We have considered two cases representing different injection strategies. In the first case, the invading fluid viscosity is constant (finite viscosity ratio) while in the second one, the invading fluid is inviscid (infinite viscosity ratio). Our results show that, for the case of finite viscosity ratio, recovery increases with $\\Delta T$ independently on strength or sign of the gradient. For an infinite viscosity ratio, a positive temperature gradient is necessary to enhance recovery. Moreover, we show that, for $\\Delta T>0$, the percentage of oil recovery generally decreases (inc...

Oliveira, C L N; Herrmann, H J

2011-01-01T23:59:59.000Z

252

Finite-Pressure-Gradient Influences on Ideal Spheromak Equilibrium  

Science Journals Connector (OSTI)

Spatially resolved measurements of the magnetic field of a spheromak have been analyzed and compared with expectations for the ratio of j?B from the pressure-gradient-free Taylor model and a model with pressure due to Morikawa. Better agreement is found with the model containing finite pressure.

G. W. Hart; C. Chin-Fatt; A. W. DeSilva; G. C. Goldenbaum; R. Hess; R. S. Shaw

1983-10-24T23:59:59.000Z

253

Simulation of IPA Gradients in Hybrid Network Systems Benjamin Melamed  

E-Print Network [OSTI]

Simulation of IPA Gradients in Hybrid Network Systems Benjamin Melamed Rutgers University Rutgers Atlanta, GA 30332 October 26, 2005 Abstract Infinitesimal Perturbation Analysis (IPA) provides formulas paths of stochastic systems. In practice, IPA derivatives may be computed either from simulation runs

254

Seasonal mass balance gradients in Norway L. A. Rasmussen1  

E-Print Network [OSTI]

Norwegian Water Resources and Energy Directorate (NVE) P. O. Box 5091 Majorstua, N-0301 Oslo, Norway16 Aug 05 Seasonal mass balance gradients in Norway L. A. Rasmussen1 and L. M. Andreassen2 1 in Norway exists in their profiles of both seasonal balances, winter bw(z) and summer bs(z). Unlike many

Rasmussen, L.A.

255

Treated Wastewater Effluent Reduces Sperm Motility Along an Osmolality Gradient  

E-Print Network [OSTI]

Treated Wastewater Effluent Reduces Sperm Motility Along an Osmolality Gradient H. L. Schoenfuss ? 2008 ? Springer Science+Business Media, LLC 2008 Abstract Many toxic effects of treated wastewater environment of treated wastewater effluent frequently differs consider- ably from that of its receiving waters

Julius, Matthew L.

256

Comparison of two-equation turbulence models for boundary layers with pressure gradient  

SciTech Connect (OSTI)

This paper compares the performance of eight low Reynolds number k-epsilon and k-omega models for high Reynolds number, incompressible turbulent boundary layers with favorable, zero, and adverse pressure gradients. Results obtained underscore the k-epsilon model's unsuitability for such flows. Even more seriously, the k-epsilon model is demonstrated to be inconsistent with the well-established physical structure of the turbulent boundary layer, and low Reynolds number corrections cannot remove the inconsistency. By contrast, the k-omega model, with and without low Reynolds number modifications, proves to be very accurate for all of the tests conducted. 16 refs.

Wilcox, D.C. (DCW Industries, Inc., La Canada, CA (United States))

1993-08-01T23:59:59.000Z

257

Wakefields in SLAC linac collimators  

Science Journals Connector (OSTI)

When a beam travels near collimator jaws, it gets an energy loss and a transverse kick due to the backreaction of the beam field diffracted from the jaws. The effect becomes very important for an intense short bunch when a tight collimation of the background beam halo is required. In the Linac Coherent Light Source at SLAC a collimation system is used to protect the undulators from radiation due to particles in the beam halo. The halo is most likely formed from gun dark current or dark current in some of the accelerating sections. However, collimators are also responsible for the generation of wake fields. The wake field effect from the collimators not only brings an additional energy jitter and change in the trajectory of the beam, but it also rotates the beam on the phase plane, which consequently leads to a degradation of the performance of the Free Electron Laser at the Linac Coherent Light Source. In this paper, we describe a model of the wake field radiation in the SLAC linac collimators. We use the results of a numerical simulation to illustrate the model. Based on the model, we derive simple formulas for the bunch energy loss and the average kick. We also present results from experimental measurements that confirm our model.

A. Novokhatski; F.-J. Decker; H. Smith; M. Sullivan

2014-12-02T23:59:59.000Z

258

High-resolution simulations of a macrotidal estuary using SUNTANS B. Wang *, O.B. Fringer, S.N. Giddings, D.A. Fong  

E-Print Network [OSTI]

with the longitudinal salinity gradient, this flow reversal results in a highly variable salinity field, which has

Fringer, Oliver B.

259

Elastic Relaxation and Correlation of Local Strain Gradients with  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Elastic Relaxation and Correlation Elastic Relaxation and Correlation of Local Strain Gradients with Ferroelectric Domains in (001) BiFeO3 Nanostructures Elastic Relaxation and Correlation of Local Strain Gradients with Ferroelectric Domains in (001) BiFeO3 Nanostructures Researchers at Argonne National Laboratory (MSD and CNM) have recently performed first worldwide studies of effects of nanopatterning on fundamental phenomena in mutiferroic BiFeO3 (BFO) nanostructures, using the APS-CNM nanoprobe beam (50 nm diameter). Nano-focused x-ray diffraction microscopy provided new insights into the relationship between film strain and ferroelectric domains in nanostructures, namely: i) an out-of-plane strain enhancement of as much as -1.8% Δc/c in a BFO film-based nanostructure relative to a planar film; ii) out-of-plane BFO C-axis

260

Gradient Plasticity Model and its Implementation into MARMOT  

SciTech Connect (OSTI)

The influence of strain gradient on deformation behavior of nuclear structural materials, such as boby centered cubic (bcc) iron alloys has been investigated. We have developed and implemented a dislocation based strain gradient crystal plasticity material model. A mesoscale crystal plasticity model for inelastic deformation of metallic material, bcc steel, has been developed and implemented numerically. Continuum Dislocation Dynamics (CDD) with a novel constitutive law based on dislocation density evolution mechanisms was developed to investigate the deformation behaviors of single crystals, as well as polycrystalline materials by coupling CDD and crystal plasticity (CP). The dislocation density evolution law in this model is mechanism-based, with parameters measured from experiments or simulated with lower-length scale models, not an empirical law with parameters back-fitted from the flow curves.

Barker, Erin I.; Li, Dongsheng; Zbib, Hussein M.; Sun, Xin

2013-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "high gradient wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Acceleration in the linear non-scaling fixed-field alternating-gradient accelerator EMMA  

SciTech Connect (OSTI)

In a fixed-field alternating-gradient (FFAG) accelerator, eliminating pulsed magnet operation permits rapid acceleration to synchrotron energies, but with a much higher beam-pulse repetition rate. Conceived in the 1950s, FFAGs are enjoying renewed interest, fuelled by the need to rapidly accelerate unstable muons for future high-energy physics colliders. Until now a 'scaling' principle has been applied to avoid beam blow-up and loss. Removing this restriction produces a new breed of FFAG, a non-scaling variant, allowing powerful advances in machine characteristics. We report on the first non-scaling FFAG, in which orbits are compacted to within 10?mm in radius over an electron momentum range of 12-18 MeV/c. In this strictly linear-gradient FFAG, unstable beam regions are crossed, but acceleration via a novel serpentine channel is so rapid that no significant beam disruption is observed. This result has significant implications for future particle accelerators, particularly muon and high-intensity proton accelerators.

Machida, S.; Barlow, R.; Berg, J.S.; Bliss, N.; Buckley, R.K.; Clarke, J.A.; Craddock, M.K.; D'Arcy, R.; Edgecock, R.; Garland, J.M.; Giboudot, Y.; /Rutherford /Huddersfield U. /Brookhaven /Daresbury /Cockcroft Inst. Accel. Sci. Tech. /TRIUMF /British Columbia U., Vancouver, Dept. Phys. Astron. /University Coll. London /Manchester U. /Brunel U. /ASP, Melbourne

2012-03-01T23:59:59.000Z

262

Bioaccumulation of Perfluorochemicals in Pacific Oyster under Different Salinity Gradients  

Science Journals Connector (OSTI)

Bioaccumulation of Perfluorochemicals in Pacific Oyster under Different Salinity Gradients ... Where Kdsw and Kd0 represent the distribution coefficients in saline and pure water, respectively, S is salinity and kads is a constant for sorption salting constant (?kads = 0.0352?). ... Based on the fact that biotransformation of PFCs is negligible (35), the faster depuration rate for PFCs at higher salinities is attributable to increases in the uptake volume of water associated with increased salinity. ...

Junho Jeon; Kurunthachalam Kannan; Han Kyu Lim; Hyo Bang Moon; Jin Sung Ra; Sang Don Kim

2010-03-15T23:59:59.000Z

263

Determination of dispersivities from a natural-gradient dispersion test  

E-Print Network [OSTI]

, and radioactive wastes. Contaminant hydrogeology is presently a focal point in the realm of hydrologic modeling. Generally, models are designed to represent simplified versions of reality and The style and format of this document was taken from the Journal... dispersivities, v ia a graphical approach, from a natural-gradient dispersion test in which artificial pollution was injected into an aquifer. The dispersion test was conducted by Sud icky et al. (1983) in order to characterize the dispersive properties...

Hoover, Caroline Marie

1985-01-01T23:59:59.000Z

264

Diffusion coefficient and radial gradient of galactic cosmic rays  

E-Print Network [OSTI]

We present the temporal changes of the diffusion coefficient K of galactic cosmic rays (GCRs) at the Earth orbit calculated based on the experimental data using two different methods. The first approach is based on the Parker convection-diffusion approximation of GCR modulation [1]: i.e. K~Vr=dI where dI is the variation of the GCR intensity measured by neutron monitors (NM),V is the solar wind velocity and r is the radial distance. The second approach is based on the interplanetary magnetic field (IMF) data. It was suggested that parallel mean free path can be expressed in terms of B as in [2]-[4]. Using data of the product of the parallel mean free path and radial gradient of GCR calculated based on the GCR anisotropy data (Ahluwalia et al., this conference ICRC 2013, poster ID: 487 [5]), we estimate the temporal changes of the radial gradient of GCR at the Earth orbit. We show that the radial gradient exhibits a strong solar cycle dependence (11-year variation) and a weak solar magnetic cycle dependence (2...

Modzelewska, Renata

2015-01-01T23:59:59.000Z

265

Considerations of ion-temperature-gradient-driven turbulence  

SciTech Connect (OSTI)

The ion-temperature-gradient-driven instability is considered in this paper. Physical pictures are presented to clarify the nature of the instability. The saturation of a single eddy is modeled by a simple nonlinear equation. It is shown that eddies that are elongated in the direction of the temperature gradient are the most unstable and have the highest saturation amplitudes. In a sheared magnetic field, such elongated eddies twist with the field lines. This structure is shown to be an alternative to the usual Fourier mode picture in which the mode is localized around the surface where {ital k}{sub {parallel}} =0. These elongated twisting eddies, which are an integral part of the ballooning mode'' structure, could survive in a torus. The elongated eddies are shown to be unstable to secondary instabilities that are driven by the large gradients in the long eddy. It is argued that the mixing length'' is affected by this nonlinear process, and is unlikely to be a linear eigenmode width.

Cowley, S.C.; Kulsrud, R.M. (Princeton Plasma Physics Laboratory, Princeton, New Jersey (USA)); Sudan, R. (Cornell University, Ithaca, New York (USA))

1991-10-01T23:59:59.000Z

266

Ciliate diversity and distribution across an environmental and depth gradient in Long Island  

E-Print Network [OSTI]

Ciliate diversity and distribution across an environmental and depth gradient in Long Island Sound- trichia (Spirotrichea) and Choreotrichia (Spirotrichea) across an environmental gradient. We assessed SSU- tion showed any clear relationship to measured environmental parameters (temperature, salinity

Katz, Laura

267

Virioplankton community structure along a salinity gradient in a solar saltern  

Science Journals Connector (OSTI)

The virioplankton community structure along a salinity gradient from near seawater (40) to saturated ... . The viral community structure changed along the salinity gradient. Cluster analysis of the viral genome-...

Ruth-Anne Sandaa; Evy Foss Skjoldal; Gunnar Bratbak

2003-10-01T23:59:59.000Z

268

Creation of nonlinear density gradients for use in internal wave research  

E-Print Network [OSTI]

A method was developed to create a nonlinear density gradient in a tank of water. Such gradients are useful for studying internal waves, an ocean phenomenon that plays an important role in climate and ocean circulation. ...

Harris, Victoria Sin

2007-01-01T23:59:59.000Z

269

Determination of deuteron quadrupole moment from calculations of the electric field gradient in D{sub 2} and HD  

SciTech Connect (OSTI)

We have carried out an accurate determination of the quadrupole moment of the deuteron nucleus. The evaluation of the constant is achieved by combining high accuracy Born-Oppenheimer calculations of the electric field gradient at the nucleus in the H{sub 2} molecule with spectroscopic measurements of the quadrupolar splitting in D{sub 2} and HD. The derived value is Q=0.285783(30) fm{sup 2}.

Pavanello, Michele; Tung Weicheng; Adamowicz, Ludwik [Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721 (United States)

2010-04-15T23:59:59.000Z

270

E-Print Network 3.0 - alpine elevation gradient Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

ecosystems, generated only by a water availability gradient, the ... Source: Colorado at Boulder, University of - Alpine Microbial Observatory Collection: Environmental...

271

E-Print Network 3.0 - african latitudinal gradient Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

richness... latitudinal gradients. Keywords Fleas, geographic range, ... Source: Poulin, Robert - Department of Zoology, University of Otago Collection: Biology and Medicine...

272

Benthic biodiversity indices versus salinity gradient in the southern Baltic Sea  

E-Print Network [OSTI]

Benthic biodiversity indices versus salinity gradient in the southern Baltic Sea Michael L. Zettler Biotic Index) and BQI (Benthic Quality Index), were tested along a salinity gradient in the southern; Ecological quality; Salinity gradient; Water Framework Directive; Oxygen depletion 1. Introduction

Zettler, Michael

273

Thin-Film Composite Pressure Retarded Osmosis Membranes for Sustainable Power Generation from Salinity Gradients  

Science Journals Connector (OSTI)

Thin-Film Composite Pressure Retarded Osmosis Membranes for Sustainable Power Generation from Salinity Gradients ... Pressure retarded osmosis has the potential to produce renewable energy from natural salinity gradients. ... Pressure retarded osmosis (PRO) and reverse electrodialysis (RED) are emerging membrane-based technologies that can convert chemical energy in salinity gradients to useful work. ...

Ngai Yin Yip; Alberto Tiraferri; William A. Phillip; Jessica D. Schiffman; Laura A. Hoover; Yu Chang Kim; Menachem Elimelech

2011-04-14T23:59:59.000Z

274

Long-term ecological dynamics: reciprocal insights from natural and anthropogenic gradients  

Science Journals Connector (OSTI)

...be studied by using natural springs that create gradients of CO2 gas, and which are at...gradients There are many natural gradients of climate...adjacent areas in natural forests in Hawaii...such as how trophic cascades and other community...

2005-01-01T23:59:59.000Z

275

Abundance and diversity of tidal marsh plants along the salinity gradient of the San Francisco Estuary: implications for global change ecology  

E-Print Network [OSTI]

plants along the salinity gradient of the San Franciscotransects along the salinity gradient of the San Franciscoacross the full salinity gradient of the San Francisco

Watson, Elizabeth Burke; Byrne, Roger

2009-01-01T23:59:59.000Z

276

High Voltage Performance of the Beam Screen of the LHC Injection Kicker Magnets  

E-Print Network [OSTI]

The LHC injection kicker magnets include beam screens to shield the ferrite yokes against wakefields resulting from the high intensity beam. The screening is provided by conductors lodged in the inner wall of a ceramic support tube. The design of the beam screen has been upgraded to overcome limitations and permit LHC operation with increasingly higher bunch intensity and short bunch lengths: the new design also significantly reduces the electric field associated with the screen conductors, decreasing the probability of electrical breakdown. The high voltage conditioning process for the upgraded kicker magnets is presented and discussed. In addition a test setup has been utilized to study flashover, on the inner wall of the ceramic tube, as a function of both applied voltage and vacuum pressure: results from the test setup are presented.

Barnes, MJ; Bregliozzi, G; Calatroni, S; Costa Pinto, P; Day, H; Ducimetire, L; Kramer, T; Namora, V; Mertens, V; Taborelli, M

2014-01-01T23:59:59.000Z

277

Salinity gradient energy potential in Colombia considering site specific constraints  

Science Journals Connector (OSTI)

Abstract The theoretical potential of salinity gradient energy in river mouth systems is the maximum amount of energy that can be extracted from the controlled mixing of river water and seawater. It is calculated using the Gibbs free energy of mixing equations considering as inputs the mean rivers' discharge and the long term salinity of the ocean basin. However, this theoretical amount of energy can be far from the reality because both, the river discharge and the salinity of the ocean, have natural variations in different time scales. In this paper we expose the site constraints related with the variability of the salinity gradients that must be considered in order to make a more accurate estimation of the available resources and calculate the so-called site specific potential for the most important and feasible river mouths of Colombia. The results show that in Colombia a mean site specific potential of 15.6GW can be achieved, mainly in the Magdalena River mouth (97% of total). But more important, the results show that the salinity structure of the studied systems have different responses to variations of the environmental forcing, despite being located in the same ocean basin, and therefore, the energy potential for each river mouth has different variability patterns at different time scales. Decreases of the estimated energy potential up to 69% were found when the site specific potential is calculated instead of the theoretical potential. This prove that more detailed input data than long term discharges and salinities are necessary in order to make accurate estimations of local and regional salinity gradient energy potentials.

Oscar Alvarez-Silva; Andrs F. Osorio

2015-01-01T23:59:59.000Z

278

Gradient index liquid crystal devices and method of fabrication thereof  

DOE Patents [OSTI]

Laser beam apodizers using cholesteric liquid crystals provides soft edge profile by use of two separate cholesteric liquid crystal mixtures with different selective reflection bands which in an overlap region have a gradient index where reflectivity changes as a function of position. The apodizers can be configured as a one-dimensional beam apod INTRODUCTION The U.S. government has rights in the invention under Contract No. DE-FC03-85DP40200 between the University of Rochester and the Department of Energy.

Lee, J.C.; Jacobs, S.

1991-10-29T23:59:59.000Z

279

Analytic energy gradients for constrained DFT-configuration interaction  

SciTech Connect (OSTI)

The constrained density functional theory-configuration interaction (CDFT-CI) method has previously been used to calculate ground-state energies and barrier heights, and to describe electronic excited states, in particular conical intersections. However, the method has been limited to evaluating the electronic energy at just a single nuclear configuration, with the gradient of the energy being available only via finite difference. In this paper, we present analytic gradients of the CDFT-CI energy with respect to nuclear coordinates, which gives the potential for accurate geometry optimization and molecular dynamics on both the ground and excited electronic states, a realm which is currently quite challenging for electronic structure theory. We report the performance of CDFT-CI geometry optimization for representative reaction transition states as well as molecules in an excited state. The overall accuracy of CDFT-CI for computing barrier heights is essentially unchanged whether the energies are evaluated at geometries obtained from quadratic configuration-interaction singles and doubles (QCISD) or CDFT-CI, indicating that CDFT-CI produces very good reaction transition states. These results open up tantalizing possibilities for future work on excited states.

Kaduk, Benjamin; Tsuchimochi, Takashi; Van Voorhis, Troy, E-mail: tvan@mit.edu [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139 (United States)

2014-05-14T23:59:59.000Z

280

Thermal Gradient Holes At Tungsten Mountain Area (Kratt, Et Al., 2008) |  

Open Energy Info (EERE)

Kratt, Et Al., 2008) Kratt, Et Al., 2008) Exploration Activity Details Location Tungsten Mountain Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness useful DOE-funding Unknown Notes twenty-three gold exploration holes were drilled by Newcrest Resources, Inc. during 2005 and 2006 along the range front. These holes approached or exceeded 300 m in depth and all holes encountered hot water and/or steam. Despite the high temperatures encountered at relatively shallow depths, there are no active geothermal features such as hot springs or steam vents at the surface. The presence of small outcrops of argillic alteration containing anomalous gold attracted the interest of exploration geologists. References Christopher Kratt, Mark Coolbaugh, Chris Sladek, Rick Zehner, Robin

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281

Grain-scale thermoelastic stresses and spatiotemporal temperature gradients on airless bodies, implications for rock breakdown  

E-Print Network [OSTI]

Thermomechanical processes such as fatigue and shock have been suggested to cause and contribute to rock breakdown on Earth, and on other planetary bodies, particularly airless bodies in the inner solar system. In this study, we modeled grain-scale stresses induced by diurnal temperature variations on simple microstructures made of pyroxene and plagioclase on various solar system bodies. We found that a heterogeneous microstructure on the Moon experiences peak tensile stresses on the order of 100 MPa. The stresses induced are controlled by the coefficient of thermal expansion and Young's modulus of the mineral constituents, and the average stress within the microstructure is determined by relative volume of each mineral. Amplification of stresses occurs at surface-parallel boundaries between adjacent mineral grains and at the tips of pore spaces. We also found that microscopic spatial and temporal surface temperature gradients do not correlate with high stresses, making them inappropriate proxies for investig...

Molaro, Jamie L; Langer, Steve A

2015-01-01T23:59:59.000Z

282

Model to interpret pulsed-field-gradient NMR data including memory and superdispersion effects  

Science Journals Connector (OSTI)

We propose a versatile model specifically designed for the quantitative interpretation of NMR velocimetry data. We use the concept of mobile or immobile tracer particles applied in dispersion theory in its Lagrangian form, adding two mechanisms: (i) independent random arrests of finite average representing intermittent periods of very low velocity zones in the mean flow direction and (ii) the possibility of unexpectedly long (but rare) displacements simulating the occurrence of very high velocities in the porous medium. Based on mathematical properties related to subordinated Lvy processes, we give analytical expressions of the signals recorded in pulsed-field-gradient NMR experiments. We illustrate how to use the model for quantifying dispersion from NMR data recorded for water flowing through a homogeneous grain pack column in single- and two-phase flow conditions.

Marie-Christine Nel; Daniela Bauer; Marc Fleury

2014-06-13T23:59:59.000Z

283

Resistance scaling for composite fermions in the presence of a density gradient.  

SciTech Connect (OSTI)

The magnetoresistance, R{sub xx}, at even-denominator fractional fillings, of an ultra high quality two-dimensional electron system at T {approx} 35 mK is observed to be strictly linear in magnetic field, B. While at 35 mK R{sub xx} is dominated by the integer and fractional quantum Hall states, at T {approx_equal} 1.2 K an almost perfect linear relationship between R{sub xx} and B emerges over the whole magnetic field range except for spikes at the integer quantum Hall states. This linear R{sub xx} cannot be understood within the Composite Fermion model, but can be explained through the existence of a density gradient in our sample.

Stormer, H. L. (Columbia University, New York, NY); Tsui, Daniel Chee (Princeton University, Princeton, NJ); Pan, Wei; West, Ken W. (Bell Labs, Murray Hill, NJ); Baldwin, K. W. (Bell Labs, Murray Hill, NJ); Pfeiffer, Loren N. (Bell Labs, Murray Hill, NJ)

2006-02-01T23:59:59.000Z

284

Thermal Gradient Holes At Chena Area (Erkan, Et. Al., 2008) | Open Energy  

Open Energy Info (EERE)

Chena Area (Erkan, Et. Al., Chena Area (Erkan, Et. Al., 2008) Exploration Activity Details Location Chena Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness useful DOE-funding Unknown Notes MULTI-STAGE DRILLING Once a hole is drilled the natural-state pressure distribution with depth is essentially unrecoverable (Grant et al., 1982). One of the best ways to mitigate this effect is to use multi-stage drilling (White et al., 1975; Grant et al., 1982). This type of drilling was applied at Chena and its usefulness in understanding the natural flow regimes is demonstrated. Here, we illustrate how high-quality equilibrium temperature logs can often be used to identify permeable fractures. The independent interpretations of flow regimes based on temperature-depth curves and the

285

Thermal Gradient Holes At Socorro Mountain Area (Owens, Et Al., 2005) |  

Open Energy Info (EERE)

Thermal Gradient Holes At Socorro Mountain Area (Owens, Et Al., 2005) Thermal Gradient Holes At Socorro Mountain Area (Owens, Et Al., 2005) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Socorro Mountain Area (Owens, Et Al., 2005) Exploration Activity Details Location Socorro Mountain Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness not indicated DOE-funding Unknown Notes Pre-existing evidence includes heat gradients of upwards of 490mW/m2 from thermal-gradient wells, tepid spring waters (32oC) and silica geochemistry indicating thermal waters with a minimum of 82 degrees C at depth References Lara Owens, Richard Baars, David Norman, Harold Tobin (2005) New Methods In Exploration At The Socorro Peak Kgra- A Gred Iii Project Retrieved from

286

Thermal Gradient Holes At Hualalai Northwest Rift Area (Thomas, 1986) |  

Open Energy Info (EERE)

Hualalai Northwest Rift Hualalai Northwest Rift Area (Thomas, 1986) Exploration Activity Details Location Hualalai Northwest Rift Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness not useful DOE-funding Unknown Notes Although not part of the current effort, two deep (approximately 2000 m) exploratory wells were drilled on the north flank of Hualalai near Puu Waawaa cinder cone. The geophysical data used for siting these wells were proprietary and hence unavailable for publication; however, the temperatures measured at the bottoms of the wells were reported to be below 20degrees C. Chemical analysis of water samples taken from these wells did not provide useful geothermal data due to contamination of the well water with drilling muds References Donald M. Thomas (1 January 1986) Geothermal Resources Assessment In

287

Ion temperature gradient driven turbulence with strong trapped ion resonance  

SciTech Connect (OSTI)

A theory to describe basic characterization of ion temperature gradient driven turbulence with strong trapped ion resonance is presented. The role of trapped ion granulations, clusters of trapped ions correlated by precession resonance, is the focus. Microscopically, the presence of trapped ion granulations leads to a sharp (logarithmic) divergence of two point phase space density correlation at small scales. Macroscopically, trapped ion granulations excite potential fluctuations that do not satisfy dispersion relation and so broaden frequency spectrum. The line width from emission due only to trapped ion granulations is calculated. The result shows that the line width depends on ion free energy and electron dissipation, which implies that non-adiabatic electrons are essential to recover non-trivial dynamics of trapped ion granulations. Relevant testable predictions are summarized.

Kosuga, Y., E-mail: kosuga@riam.kyushu-u.ac.jp [Institute for Advanced Study, Kyushu University, Fukuoka (Japan); Research Institute for Applied Mechanics, Kyushu University, Fukuoka (Japan); Itoh, S.-I. [Research Center for Plasma Turbulence, Kyushu University, Fukuoka (Japan); Research Institute for Applied Mechanics, Kyushu University, Fukuoka (Japan); Diamond, P. H. [CASS and CMTFO, University of California at San Diego, La Jolla, California 92093 (United States); WCI Center for Fusion Theory, National Fusion Research Institute, Daejeon (Korea, Republic of); Itoh, K. [National Institute for Fusion Science, Gifu (Japan); Research Center for Plasma Turbulence, Kyushu University, Fukuoka (Japan); Lesur, M. [Research Institute for Applied Mechanics, Kyushu University, Fukuoka (Japan)

2014-10-15T23:59:59.000Z

288

Optimization of the Oktay-Kronfeld Action Conjugate Gradient Inverter  

E-Print Network [OSTI]

Improving the Fermilab action to third order in heavy quark effective theory yields the Oktay-Kronfeld action, a promising candidate for precise calculations of the spectra of heavy quark systems and weak matrix elements relevant to searches for new physics. We have optimized the bi-stabilized conjugate gradient inverter in the SciDAC QOPQDP library and are developing a GPU code. The action is rewritten and the needed gauge-link combinations are precalculated. In tests with a MILC coarse lattice, this procedure accelerates the inverter by a factor of four. The remaining floating-point operations are mostly simple matrix multiplications between gauge links and fermion vectors, which we accelerate by more than an order of magnitude by using CUDA. Further gains could be achieved by using QUDA.

Yong-Chull Jang; Jon A. Bailey; Weonjong Lee; Carleton DeTar; Mehmet B. Oktay; Andreas S. Kronfeld

2013-11-21T23:59:59.000Z

289

Salinity gradient solar pond technology applied to potash solution mining  

SciTech Connect (OSTI)

A solution mining facility at the Eddy Potash Mine, Eddy County, New Mexico has been proposed that will utilize salinity gradient solar pond (SGSP) technology to supply industrial process thermal energy. The process will include underground dissolution of potassium chloride (KCl) from pillars and other reserves remaining after completion of primary room and pillar mining using recirculating solutions heated in the SGSP. Production of KCl will involve cold crystallization followed by a cooling pond stage, with the spent brine being recirculated in a closed loop back to the SGSP for reheating. This research uses SGSP as a renewable, clean energy source to optimize the entire mining process, minimize environmental wastes, provide a safe, more economical extraction process and reduce the need for conventional processing by crushing, grinding and flotation. The applications of SGSP technology will not only save energy in the extraction and beneficiation processes, but also will produce excess energy available for power generation, desalination, and auxiliary structure heating.

Martell, J.A.; Aimone-Martin, C.T.

2000-06-12T23:59:59.000Z

290

Acoustical power amplification and damping by temperature gradients  

Science Journals Connector (OSTI)

Ceperley proposed a concept of a traveling wave heat engine [A pistonless Stirling engineThe traveling wave heat engine J. Acoust. Soc. Am. 66 15081513 (1979).] that provided a starting point of thermoacoustics today. This paper verifies experimentally his idea through observation of amplification and strong damping of a plane acoustic traveling wave as it passes through axial temperature gradients. The acoustic power gain is shown to obey a universal curve specified by a dimensionless parameter ???; ? is the angular frequency and ?? is the relaxation time for the gas to thermally equilibrate with channel walls. As an application of his idea a three-stage acoustic power amplifier is developed which attains the gain up to 10 with a moderate temperature ratio of 2.3.

Tetsushi Biwa; Ryo Komatsu; Taichi Yazaki

2011-01-01T23:59:59.000Z

291

Coherent structures in ion temperature gradient turbulence-zonal flow  

SciTech Connect (OSTI)

Nonlinear stationary structure formation in the coupled ion temperature gradient (ITG)-zonal flow system is investigated. The ITG turbulence is described by a wave-kinetic equation for the action density of the ITG mode, and the longer scale zonal mode is described by a dynamic equation for the m?=?n?=?0 component of the potential. Two populations of trapped and untrapped drift wave trajectories are shown to exist in a moving frame of reference. This novel effect leads to the formation of nonlinear stationary structures. It is shown that the ITG turbulence can self-consistently sustain coherent, radially propagating modulation envelope structures such as solitons, shocks, and nonlinear wave trains.

Singh, Rameswar, E-mail: rameswar.singh@lpp.polytechnique.fr [Laboratoire de Physique des Plasmas, Ecole Polytechnique, Route de Saclay, 91128 Palaiseau Cedex (France); Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India); Singh, R. [Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India); WCI Center for Fusion Theory, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Kaw, P. [Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India); Grcan, . D. [Laboratoire de Physique des Plasmas, Ecole Polytechnique, Route de Saclay, 91128 Palaiseau Cedex (France); Diamond, P. H. [WCI Center for Fusion Theory, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); CMTFO and CASS, University of California, San Diego, California 92093 (United States)

2014-10-15T23:59:59.000Z

292

Thermal Gradient Holes At Coso Geothermal Area (1974) | Open Energy  

Open Energy Info (EERE)

Coso Geothermal Area (1974) Coso Geothermal Area (1974) Exploration Activity Details Location Coso Geothermal Area Exploration Technique Thermal Gradient Holes Activity Date 1974 Usefulness useful DOE-funding Unknown Exploration Basis Use heat flow studies for the first time at Coso to indicate the presence or absence of abnormal heat Notes Located 10 sites for heat flow boreholes using available seismic ground noise and electrical resistivity data; data collected from 9 of 10; thermal conductivity measurements were completed using both the needle probe technique and the divided bar apparatus with a cell arrangement. In the upper few hundred meters of the subsurface heat is being transferred by a conductive heat transfer mechanism with a value of ~ 15 µcal/cm2sec; the background heat flow is ~ 3.5 HFU.

293

 

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

> Witness Gun > Witness Gun AWA Home Page AWA Activities AWA Facilities AWA Group Meetings AWA Safety Discussions AWA Safety & Procedure Manual AWA News AWA QR Codes WF Notes AGN Notes (Internal) US High Gradient Collaboration Meeting Other Related Links Security and Privacy Notice Witness Gun The AWA witness gun is a 6 cell pi/2 mode rf photoinjector, capable of generating 0.5 nC, 8 ps electron bunches at 4 MeV. The witness beam is used to diagnose wakefields generated by the high current drive beam. Using an optical trombone to vary the laser timing at the photocathode while adjusting the witness gun rf phase the witness bunch can be continuously delayed up to 10 ns relative to the drive bunch for wakefield measurements. AWA Beamlines The diagram shows the witness gun in relation to the drive linac and wakefield device test section. This configuration is used for experiments which employ collinear drive and witness beams. The beamlines are currently being reconfigured to allow parallel drive and witness beams needed for dielectric wakefield transformer measurements.

294

THE EXTENSIVE AGE GRADIENT OF THE CARINA DWARF GALAXY  

SciTech Connect (OSTI)

The evolution of small systems such as dwarf spheroidal galaxies (dSphs) is likely to have been a balance between external environmental effects and internal processes within their own relatively shallow potential wells. Assessing how strong such environmental interactions may have been is therefore an important element in understanding the baryonic evolution of dSphs and their derived dark matter distribution. Here we present results from a wide-area CTIO/MOSAIC II photometric survey of the Carina dSph, reaching down to about two magnitudes below the oldest main-sequence turnoff (MSTO). This data set enables us to trace the structure of Carina in detail out to very large distances from its center, and as a function of stellar age. We observe the presence of an extended structure made up primarily of ancient MSTO stars, at distances between 25' and 60' from Carina's center, confirming results in the literature that Carina extends well beyond its nominal tidal radius. The large number statistics of our survey reveals features such as isophote twists and tails that were undetected in other previous, shallower surveys. This is the first time that such unambiguous signs of tidal disruption have been found in a Milky Way 'classical' dwarf other than Sagittarius. We also demonstrate the presence of a negative age gradient in Carina directly from its MSTOs, and trace it out to very large distances from the galaxy center. The signs of interaction with the Milky Way make it unclear whether the age gradient was already in place before Carina underwent tidal disruption.

Battaglia, G. [INAF-Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Irwin, M. [Institute of Astronomy, Madingley Road, Cambridge CB03 0HA (United Kingdom); Tolstoy, E.; De Boer, T. [Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700 AV Groningen (Netherlands); Mateo, M., E-mail: gbattaglia@oabo.inaf.it [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109-1090 (United States)

2012-12-20T23:59:59.000Z

295

Nekton community change along estuarine salinity gradients: Can salinity zones be defined?  

Science Journals Connector (OSTI)

Organisms tend to inhabit predictable portions of estuaries along salinity gradients between the ocean inlets (salinity > 35 psu) and the freshwater tributaries (salinity = 0). Previous studies have suggested ......

Marin F. D. Greenwood

2007-06-01T23:59:59.000Z

296

Species richness, diversity and density of understory vegetation along disturbance gradients in the Himalayan conifer forest  

Science Journals Connector (OSTI)

We investigated whether species richness, diversity and density of understory herbaceous plants differed along logging (gap) and grazing (primarily by cattle) disturbance gradients, and sought to identify drivers...

Kesang Wangchuk; Andrs Darabant; Prem Bahadur Rai

2014-09-01T23:59:59.000Z

297

Thermal Gradient Holes At Fort Bliss Area (DOE GTP) | Open Energy...  

Open Energy Info (EERE)

Fort Bliss Area (DOE GTP) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Fort Bliss Area (DOE GTP) Exploration...

298

Towards a theory of ecotone resilience: Coastal vegetation on a salinity gradient  

Science Journals Connector (OSTI)

Ecotones represent locations where vegetation change is likely to occur as a result of climate and other environmental changes. Using a model of an ecotone vulnerable to such future changes, we estimated the resilience of the ecotone to disturbances. The specific ecotone is that between two different vegetation types, salinity-tolerant and salinity-intolerant, along a gradient in groundwater salinity. In the case studied, each vegetation type, through soil feedback loops, promoted local soil salinity levels that favor itself in competition with the other type. Bifurcation analysis was used to study the system of equations for the two vegetation types and soil salinity. Alternative stable equilibria, one for salinity-tolerant and one for salinity intolerant vegetation, were shown to exist over a region of the groundwater salinity gradient, bounded by two bifurcation points. This region was shown to depend sensitively on parameters such as the rate of upward infiltration of salinity from groundwater into the soil due to evaporation. We showed also that increasing diffusion rates of vegetation can lead to shrinkage of the range between the two bifurcation points. Sharp ecotones are typical of salt-tolerant vegetation (mangroves) near the coastline and salt-intolerant vegetation inland, even though the underlying elevation and groundwater salinity change very gradually. A disturbance such as an input of salinity to the soil from a storm surge could upset this stable boundary, leading to a regime shift of salinity-tolerant vegetation inland. We showed, however, that, for our model as least, a simple pulse disturbance would not be sufficient; the salinity would have to be held at a high level, as a press, for some time. The approach used here should be generalizable to study the resilience of a variety of ecotones to disturbances.

Jiang Jiang; Daozhou Gao; Donald L. DeAngelis

2012-01-01T23:59:59.000Z

299

Parametric Excitation of Geodesic Acoustic Modes by Electron Drift Waves and Ion Temperature Gradient Modes in Tokamak Plasmas  

SciTech Connect (OSTI)

Geodesic Acoustic Modes (GAMs) have been predicted and subsequently observed in many toroidal plasma devices. Bicoherence studies on various devices have suggested three-wave mode coupling processes between GAMs and high frequency turbulence. Thus the parametric coupling of GAMS to drift waves and/or ion temperature gradient(ITG{r_brace} modes is a potential candidate for excitation of these modes. In this paper we discuss the resonant three-wave coupling mechanism for the excitation of GAMs by ITG and finite beta drift waves in homogeneous and inhomogeneous plasmas and compare theoretical predictions with observed characteristics of the GAMs.

Guzdar, P. N.; Kleva, R. G. [IREAP, University of Maryland, College Park, MD 20742 (United States); Chakrabarti, N. [SINP, Kolkata (India); Kaw, P. K.; Singh, R. [IPR, Gandhinagar, 308423 (India); Naulin, V.; Rasmussen, J. J. [EURATOM, Roskilde (Denmark)

2008-11-01T23:59:59.000Z

300

Effects of pressure gradient on global Alfvn eigenmodes in reversed field pinch  

SciTech Connect (OSTI)

The effects of pressure gradient on the existence of global Alfvn eigenmodes (GAE) in Reversed Field Pinch are studied by numerical calculation. It is found that GAEs near the plasma core can exist when pressure gradient is sufficiently large. The calculated mode frequency and structure are consistent with the experimental results in the Madison Symmetric Torus.

Cai, Huishan, E-mail: hscai@mail.ustc.edu.cn [CAS Key Laboratory of Geospace Environment, Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China)] [CAS Key Laboratory of Geospace Environment, Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China); Fu, Guoyong, E-mail: fu@pppl.gov [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)] [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Lin, Liang; Ding, Weixing; Brower, D. L. [Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095 (United States)] [Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095 (United States); Liu, D. Y. [Physics Department, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)] [Physics Department, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Hu, Y. J. [Institute of Plasma Physics, CAS (China)] [Institute of Plasma Physics, CAS (China)

2014-02-15T23:59:59.000Z

Note: This page contains sample records for the topic "high gradient wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Quantification of the electrochemical proton gradient and activation of ATP synthase in leaves  

E-Print Network [OSTI]

Quantification of the electrochemical proton gradient and activation of ATP synthase in leaves Available online 12 April 2008 Keywords: ATP synthase Electrochemical proton gradient Membrane potential We of the ATP synthase (Junge, W., Rumberg, B. and Schröder, H., Eur. J. Biochem. 14 (1970) 575

302

Supercurrent-Induced Temperature Gradient across a Nonequilibrium SNS Josephson Junction M. S. Crosser,1  

E-Print Network [OSTI]

Supercurrent-Induced Temperature Gradient across a Nonequilibrium SNS Josephson Junction M. S direction. The feature represents an effective temperature gradient across the SNS Josephson junction Josephson junction (SNS JJ) into a `` junction'' by driving the electron energy distribution far from

Birge, Norman

303

SYNTHESIS Evolution and the latitudinal diversity gradient: speciation, extinction and biogeography  

E-Print Network [OSTI]

, USA 7 Center for Marine Biodiversity and Conservation, Scripps Insti- tution of Oceanography and Michael Turelli18 Abstract A latitudinal gradient in biodiversity has existed since before the time gradient represents a major challenge to future research. Keywords Biodiversity, biotic interactions

Roy, Kaustuv

304

Deformation-induced inverted metamorphic eld gradients: an example from the southeastern Canadian Cordillera  

E-Print Network [OSTI]

Deformation-induced inverted metamorphic ®eld gradients: an example from the southeastern Canadian allochthon and Monashee complex, exhibits an inverted metamorphic ®eld gradient. New data presented preserving evidence of strongly diachronous deformation and an apparent inverted metamorphism. # 1999

Gibson, Dan

305

Thermodynamic, Energy Efficiency, and Power Density Analysis of Reverse Electrodialysis Power Generation with Natural Salinity Gradients  

Science Journals Connector (OSTI)

Thermodynamic, Energy Efficiency, and Power Density Analysis of Reverse Electrodialysis Power Generation with Natural Salinity Gradients ... solns. of different salinities. ... River mouths are potentially abundant locations for the exploitation of the clean and renewable salinity gradient energy (SGE) as here perpetually fresh water mixes with saline seawater. ...

Ngai Yin Yip; David A. Vermaas; Kitty Nijmeijer; Menachem Elimelech

2014-04-03T23:59:59.000Z

306

Regional patterns and controls of ecosystem salinization with grassland afforestation along a rainfall gradient  

E-Print Network [OSTI]

salinization with grassland afforestation along a rainfall gradient, Global Biogeochem. Cycles, 22, GB2015, doiRegional patterns and controls of ecosystem salinization with grassland afforestation along a rainfall gradient M. D. Nosetto,1,2 E. G. Jobba´gy,1 T. To´th,3 and R. B. Jackson4,5 Received 25 April 2007

Jackson, Robert B.

307

Sub-100 nm Confinement of Magnetic Nanoparticles Using Localized Magnetic Field Gradients  

E-Print Network [OSTI]

that generate large magnetic gradients. In a homogeneous magnetic field, the field lines are parallel; that is, then the field lines converge into the ferromagnet. This convergence forms a shallow magnetic field gradient, to minimize the magnetic potential energy, the field lines exiting one magnet converge into the other magnet

Prentiss, Mara

308

Ionosphere Spatial Gradient Threat for LAAS: Mitigation and Tolerable Threat Space  

E-Print Network [OSTI]

1 Ionosphere Spatial Gradient Threat for LAAS: Mitigation and Tolerable Threat Space Ming Luo, Sam and a threat space was extrapolated based on the 6 April 2000 ionospheric storm. It was showed that the impact of the ionospheric anomalies depends on the threat parameters, namely, the ionospheric gradient, the slope width

Stanford University

309

Integrated thermal-microstructure model to predict the property gradients in resistance spot steel welds  

SciTech Connect (OSTI)

An integrated model approach was proposed for relating resistance welding parameters to weldment properties. An existing microstructure model was used to determine the microstructural and property gradients in resistance spot welds of plain carbon steel. The effect of these gradients on the weld integrity was evaluated with finite element analysis. Further modifications to this integrated thermal-microstructure model are discussed.

Babu, S.S.; Riemer, B.W.; Santella, M.L. [Oak Ridge National Lab., TN (United States); Feng, Z. [Edison Welding Inst., Columbus, OH (United States)

1998-11-01T23:59:59.000Z

310

Development and propagation of a pollution gradient in the marine boundary layer during INDOEX (1999)  

E-Print Network [OSTI]

Development and propagation of a pollution gradient in the marine boundary layer during INDOEX (1999) Matthew Simpson and Sethu Raman Department of Marine, Earth, and Atmospheric Sciences, North and propagation of a pollution gradient in the marine boundary layer over the Arabian Sea during the Intensive

Raman, Sethu

311

Spatially resolved lasers using a glassy cholesteric liquid crystal film with lateral pitch gradient  

E-Print Network [OSTI]

Spatially resolved lasers using a glassy cholesteric liquid crystal film with lateral pitch crystal CLC lasers, a lateral pitch gradient was introduced by thermally activated diffusion across efficiencies, 0.2%­1.5%, are superior to those reported to date for gradient-pitch CLC lasers. © 2011 American

Chen, Shaw H.

312

Global energy gradients and size in colonial organisms: Worker mass and worker number  

E-Print Network [OSTI]

Global energy gradients and size in colonial organisms: Worker mass and worker number in ant size varies globally is a key challenge to ecology. Solar energy may shape gradients of body size by its effects on local temperature and net primary productivity (16­20). Rising global temperatures (21

Kaspari, Mike

313

Brine clarity maintenance in salinity-gradient solar ponds  

Science Journals Connector (OSTI)

Brine transparency is an important part of the maintenance of a salinity-gradient solar pond as it affects the amount of solar radiation reaching the storage zone and hence has an influence on the thermal performance. There is a wide range of factors that can hinder the transmission of light in a solar pond. Algal and microbial growths are the most common problems encountered in working solar ponds and control of their densities is essential to maintain transparency. Two different chemical treatment methods for algae growth prevention are described in this paper: chlorine and a novel chemical product copper ethylamine complex. The latter method has never been implemented previously in a working pond. This paper discusses the theory of the algae control methods used and presents the experimental results of the chemical treatments. The results showed that Cupricide is more effective than chlorine and is therefore the recommended chemical for algae control in solar ponds; it improves the water transparency especially in the upper convective zone and lower convective zone with all measurement values less than 1 NTU. Chlorine was found to be more corrosive than Cupricide due to the acidic effect it has on the pH. The preliminary cost analysis showed that granular chlorine is the cheapest chemical. A more detailed financial analysis is nevertheless required to refine these costs.

Neus Gasulla; Yusli Yaakob; Jimmy Leblanc; Aliakbar Akbarzadeh; Jose Luis Cortina

2011-01-01T23:59:59.000Z

314

GRADIENT INDEX SPHERES BY THE SEQUENTIAL ACCRETION OF GLASS POWDERS  

SciTech Connect (OSTI)

The Department of Energy is seeking a method for fabricating mm-scale spheres having a refractive index that varies smoothly and continuously from the center to its surface [1]. The fabrication procedure must allow the creation of a range of index profiles. The spheres are to be optically transparent and have a refractive index differential greater than 0.2. The sphere materials can be either organic or inorganic and the fabrication technique must be capable of scaling to low cost production. Mo-Sci Corporation proposed to develop optical quality gradient refractive index (GRIN) glass spheres of millimeter scale (1 to 2 mm diameter) by the sequential accretion and consolidation of glass powders. Other techniques were also tested to make GRIN spheres as the powder-accretion method produced non-concentric layers and poor optical quality glass spheres. Potential ways to make the GRIN spheres were (1) by "coating" glass spheres (1 to 2 mm diameter) with molten glass in a two step process; and (2) by coating glass spheres with polymer layers.

MARIANO VELEZ

2008-06-15T23:59:59.000Z

315

Malignant Neoplasms among Residents of a Blackfoot Disease-endemic Area in Taiwan: High-Arsenic Artesian Well Water and Cancers  

Science Journals Connector (OSTI)

...of this area also has a high salinity. For this reason, some residents...There was a decreasing gradient of BFD prevalence rate following...Ichu following a declining gradient of BFD prevalence rate. The...township. However, the declining gradient of SMRs was not in the order...

Chien-Jen Chen; Ya-Chien Chuang; Tong-Ming Lin; and Hsin-Yin Wu

1985-11-01T23:59:59.000Z

316

Thermal Gradient Holes At Salt Wells Area (Bureau of Land Management, 2009)  

Open Energy Info (EERE)

Thermal Gradient Holes At Salt Wells Area (Bureau of Land Management, 2009) Thermal Gradient Holes At Salt Wells Area (Bureau of Land Management, 2009) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Salt Wells Area (Bureau of Land Management, 2009) Exploration Activity Details Location Salt Wells Geothermal Area Exploration Technique Thermal Gradient Holes Activity Date 2008 - 2008 Usefulness not indicated DOE-funding Unknown Exploration Basis Vulcan increased exploration efforts in the summer and fall of 2008, during which time the company drilled two temperature gradient holes (86-15 O on Pad 1 and 17-16 O on Pad 3); conducted seismic, gravity and magnetotelluric surveys; and drilled deep exploration wells at Pads 6 and 8 and binary wells at Pads 1, 2, 4, and 7. Notes

317

Thermal Gradient Holes At Hot Springs Ranch Area (Szybinski, 2006) | Open  

Open Energy Info (EERE)

Thermal Gradient Holes At Hot Springs Ranch Area (Szybinski, 2006) Thermal Gradient Holes At Hot Springs Ranch Area (Szybinski, 2006) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Hot Springs Ranch Area (Szybinski, 2006) Exploration Activity Details Location Hot Springs Ranch Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness useful DOE-funding Unknown Notes In 2005, Nevada Geothermal Power Company drilled four geothermal gradient wells, PVTG-1, -2, -3, and -4, and all four encountered geothermal fluids. The holes provided valuable water geochemistry, supporting the geothermometry results obtained from the hot springs and Magma well. The temperature data gathered from all the wells clearly indicates the presence of a major plume of thermal water centered on the Pumpernickel Valley

318

Thermal Gradient Holes At Chocolate Mountains Area (Alm, Et Al., 2010) |  

Open Energy Info (EERE)

Chocolate Mountains Area (Alm, Et Al., 2010) Chocolate Mountains Area (Alm, Et Al., 2010) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Chocolate Mountains Area (Alm, Et Al., 2010) Exploration Activity Details Location Chocolate Mountains Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness useful DOE-funding Unknown Notes "Shallow temperature gradient drilling began at the CMAGR in January of 2010. 13 temperature gradient holes were completed to a depth of 500' below ground surface. Sites were selected based on the compilation of previous exploration and resulting data is being integrated into the most recent geologic model. This model will form the basis for the selection of a deeper (2000'-4000') temperature gradient drilling campaign at the CMAGR in

319

Thermal Gradient Holes At Lightning Dock Area (Cunniff & Bowers, 2005) |  

Open Energy Info (EERE)

Thermal Gradient Holes At Lightning Dock Area Thermal Gradient Holes At Lightning Dock Area (Cunniff & Bowers, 2005) Exploration Activity Details Location Lightning Dock Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness not indicated DOE-funding Unknown Notes The two gradient holes were sited on federal geothermal leases owned by Lightning Dock Geothermal, Inc. and both were drilled into lakebed sediments some distance from the intense shallow geothermal anomaly located in the eastern half of Section 7, Township 25 South, Range 19 West. References Roy A. Cunniff, Roger L. Bowers (2005) Final Technical Report, Geothermal Resource Evaluation And Definitioni (Gred) Program-Phases I, Ii, And Iii For The Animas Valley, Nm Geothermal Resource Retrieved from "http://en.openei.org/w/index.php?title=Thermal_Gradient_Holes_At_Lightning_Dock_Area_(Cunniff_%26_Bowers,_2005)&oldid=387460"

320

The Chemistry of Atherogenic High Density Lipoprotein  

E-Print Network [OSTI]

TRL Bouyant triglyceride-rich lipoprotein C18 Carbon tail of eighteen atoms CE Capillary electrophoresis CETP Cholesterol ester transfer protein CM Chylomicrons CsCdY dicesium cadmium ethylenediaminetetraacetic acid CAD Coronary artery disease CVD... Cardiovascular disease DGU Density gradient ultracentrifugation I-DGU Immunospecific-density gradient ultracentrifugation DMSO Dimethyl sulfoxide DS Dextran sulfate dTRL Dense triglyceride rich lipoprotein EDTA Ethyelenediaminetetraacetic acid HDL High...

Moore, D'Vesharronne J.

2012-07-16T23:59:59.000Z

Note: This page contains sample records for the topic "high gradient wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Microscale geochemical gradients in Hanford 300 Area sediment biofilms and influence of uranium  

SciTech Connect (OSTI)

The presence and importance of microenvironments in the subsurface at contaminated sites were suggested by previous geochemical studies. However, no direct quantitative characterization of the geochemical microenvironments had been reported. We quantitatively characterized microscale geochemical gradients (dissolved oxygen (DO), H(2), pH, and redox potential) in Hanford 300A subsurface sediment biofilms. Our results revealed significant differences in geochemical parameters across the sediment biofilm/water interface in the presence and absence of U(VI) under oxic and anoxic conditions. While the pH was relatively constant within the sediment biofilm, the redox potential and the DO and H(2) concentrations were heterogeneous at the microscale (<500-1000 ?m). We found microenvironments with high DO levels (DO hotspots) when the sediment biofilm was exposed to U(VI). On the other hand, we found hotspots (high concentrations) of H(2) under anoxic conditions both in the presence and in the absence of U(VI). The presence of anoxic microenvironments inside the sediment biofilms suggests that U(VI) reduction proceeds under bulk oxic conditions. To test this, we operated our biofilm reactor under air-saturated conditions in the presence of U(VI) and characterized U speciation in the sediment biofilm. U L(III)-edge X-ray absorption spectroscopy (XANES and EXAFS) showed that 80-85% of the U was in the U(IV) valence state.

Nguyen, Hung D.; Cao, Bin; Mishra, Bhoopesh; Boyanov, Maxim I.; Kemner, Kenneth M.; Fredrickson, Jim K.; Beyenal, Haluk

2012-01-01T23:59:59.000Z

322

Automated analysis for detecting beams in laser wakefield simulations Daniela M. Ushizima, Oliver Rubel, Prabhat, Gunther H. Weber, E. Wes Bethel, Cecilia R. Aragon  

E-Print Network [OSTI]

to generate electric fields thousands of times higher than those of conventional accelerators. The resulting as nodes in a minimum spanning tree. Second, we partition the multivariate data using fuzzy clustering are then con- centrated near a single energy [8], when a high quality beam can form. PIC codes model

Geddes, Cameron Guy Robinson

323

Investigation of iron opacity experiment plasma gradients with synthetic data analyses  

SciTech Connect (OSTI)

Experiments have been performed at Sandia National Laboratories Z-facility to validate iron opacity models relevant to the solar convection/radiation zone boundary. Sample conditions were measured by mixing Mg with the Fe and using Mg K-shell line transmission spectra, assuming that the plasma was uniform. We develop a spectral model that accounts for hypothetical gradients, and compute synthetic spectra to quantitatively evaluate the plasma gradient size that can be diagnosed. Two sample designs are investigated, assuming linear temperature and density gradients. First, Mg uniformly mixed with Fe enables temperature gradients greater than 10% to be detected. The second design uses Mg mixed into one side and Al mixed into the other side of the sample in an attempt to more accurately infer the sample gradient. Both temperature and density gradients as small as a few percent can be detected with this design. Experiments have successfully recorded spectra with the second design. In future research, the spectral model will be used to place bounds on gradients that exist in Z opacity experiments.

Nagayama, T.; Bailey, J. E.; Rochau, G. A.; Hansen, S. B. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Mancini, R. C. [Physics Department, University of Nevada, Reno, Nevada 89557 (United States); MacFarlane, J. J.; Golovkin, I. [Prism Computational Sciences, Madison, Wisconsin 53703 (United States)

2012-10-15T23:59:59.000Z

324

Observation of a Magnetic Modulation of the Lattice Electric-Field Gradient of Fe2+ Substituted in 1T-TaS2  

Science Journals Connector (OSTI)

An unusual temperature dependence of the quadrupole splitting of Fe2+ in 1T-Fe0.1Ta0.9S2 can be understood in terms of a magnetic modulation of the lattice electric-field gradient. This modulation is produced by a strictive interaction between the local lattice environment and the continuous low-spin-high-spin transition of Fe2+. The onset of the charge-density-wave instability can also be observed.

M. Eibschtz and M. E. Lines

1977-09-12T23:59:59.000Z

325

Thermal Gradient Holes At Blue Mountain Area (Fairbank & Neggemann, 2004) |  

Open Energy Info (EERE)

Blue Mountain Area (Fairbank & Neggemann, 2004) Blue Mountain Area (Fairbank & Neggemann, 2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Blue Mountain Area (Fairbank & Neggemann, 2004) Exploration Activity Details Location Blue Mountain Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness useful DOE-funding Unknown References Brian D. Fairbank, Kim V. Niggemann (2004) Deep Blue No 1- A Slimhole Geothermal Discovery At Blue Mountain, Humboldt County, Nevada Retrieved from "http://en.openei.org/w/index.php?title=Thermal_Gradient_Holes_At_Blue_Mountain_Area_(Fairbank_%26_Neggemann,_2004)&oldid=386709" Category: Exploration Activities What links here Related changes Special pages Printable version Permanent link

326

Nonlinear Gyrokinetic Simulations of Ion-Temperature-Gradient Turbulence for the Optimized Wendelstein 7-X Stellarator  

SciTech Connect (OSTI)

Ion-temperature-gradient turbulence constitutes a possibly dominant transport mechanism for optimized stellarators, in view of the effective suppression of neoclassical losses characterizing these devices. Nonlinear gyrokinetic simulation results for the Wendelstein 7-X stellarator [G. Grieger et al., in Proceedings of the IAEA Conference on Plasma Physics and Controlled Nuclear Fusion Research, 1990 (IAEA, Vienna, 1991) Vol. 3, p. 525]--assuming an adiabatic electron response--are presented. Several fundamental features are discussed, including the role of zonal flows for turbulence saturation, the resulting flux-gradient relationship, and the coexistence of ion-temperature-gradient modes with trapped ion modes in the saturated state.

Xanthopoulos, P. [Max-Planck-Institut fuer Plasmaphysik, Teilinstitut Greifswald, Wendelsteinstrasse 1, D-17491 Greifswald (Germany); Merz, F.; Goerler, T.; Jenko, F. [Max-Planck-Institut fuer Plasmaphysik, Boltzmannstrasse 2, D-85748 Garching (Germany)

2007-07-20T23:59:59.000Z

327

An Elementary Extension of Korn's First Inequality to H(Curl) motivated by Gradient Plasticity with Plastic Spin  

E-Print Network [OSTI]

We prove a Korn-type inequality for tensor fields without gradient structure, which generalizes Korn's first inequality.

Patrizio Neff; Dirk Pauly; Karl-Josef Witsch

2011-06-30T23:59:59.000Z

328

In situ generation of pH gradients in microfluidic devices for biofabrication of freestanding, semi-permeable chitosan membranes  

E-Print Network [OSTI]

In situ generation of pH gradients in microfluidic devices for biofabrication of freestanding, semiH gradients in microfluidic devices for biofabrication of freestanding, semi-permeable chitosan membranes membrane structure in microfluidic networks where pH gradients are generated at the converging interface

Rubloff, Gary W.

329

From the mountains to the sea: assemblage structure and dynamics in Chironomidae (Insecta: Diptera) in the Clyde River estuarine gradient,  

E-Print Network [OSTI]

and non-random with respect to spatial position along the salinity gradient although relatively random with respect to temporal shifts between the five seasonal samples. Generally, the salinity gradient had strong). The estuarine salinity gradient balance also may affect bioaccumulation of heavy metals and trans- port

Cranston, Peter S.

330

Brookhaven High Energy Physics  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

High-Energy Physics High-Energy Physics High-energy physicists probe the properties and behavior of the most elementary particles in the universe. At the Alternating Gradient Synchrotron (AGS), they perform experiments of unique sensitivity using high-intensity, intermediate-energy beams. The AGS currently provides the world's most intense high-energy proton beam. It is also the world's most versatile accelerator, accelerating protons, polarized protons, and heavy ions to near the speed of light. Magnet system at Brookhaven used to measure the magnetic moment of the muon. Important discoveries in high-energy physics were made at the AGS within the last decade. An international collaboration, including key physicists from Brookhaven, performed a very high-precision measurement of a property

331

The evolution of high energy accelerators  

SciTech Connect (OSTI)

Accelerators have been devised and built for two reasons: In the first place, by physicists who needed high energy particles in order to have a means to explore the interactions between particles that probe the fundamental elementary forces of nature. And conversely, sometimes accelerator builders produce new machines for higher energy than ever before just because it can be done, and then challenge potential users to make new discoveries with the new means at hand. These two approaches or motivations have gone hand in hand. This lecture traces how high energy particle accelerators have grown from tools used for esoteric small-scale experiments to the gigantic projects of today. So far all the really high-energy machines built and planned in the world--except the SLC--have been ring accelerators and storage rings using the strong-focusing method. But this method has not removed the energy limit, it has only pushed it higher. It would seem unlikely that one can go beyond the Large Hadron Collider (LHC)--but in fact a workshop was held in Sicily in November 1991, concerned with the question of extrapolating to 100 TeV. Other acceleration and beam-forming methods are now being discussed--collective fields, laser acceleration, wake-field accelerators etc., all aimed primarily at making linear colliders possible and more attractive than with present radiofrequency methods. So far it is not entirely clear which of these schemes will dominate particle physics in the future--maybe something that has not been thought of as yet.

Courant, E.D.

1994-08-01T23:59:59.000Z

332

Laboratory measurements of acoustic scattering from a temperature and salinity gradient  

Science Journals Connector (OSTI)

Recently developed theoretical scattering models predict that acoustic scattering from temperature and salinity microstructure at high frequencies (10 kHz1 MHz) can be significant under certain oceanographic conditions. The results of this theoretical work suggest that it may be possible to use acoustic scattering techniques in combination with the scattering models to estimate oceanographic parameters such as the dissipation rate of turbulent kinetic energy. In addition quantification of the scattering contributions from temperature and salinity microstructure can play an important role in correctly interpreting acoustic surveys of marine life since recent field data indicate that the acoustic returns from zooplankton and microstructure can be of similar strength. Acoustic backscatter from a sharp temperature and salinity gradient was measured in a tank capable of generating and sustaining a thin double?diffusive layer (12 cm thick) between two water masses (cold fresh residing above warm salty water). Vertical shear temperature and salinity profiles were measured during the experiment to provide input to the acoustic scattering models. Backscatter was measured at frequencies between 24 kHz and 500 kHz and as a function of range from the sharp interface as part of a program to measure the backscattering from microstructure. a)Currently at Southwest Fisheries Science Center La Jolla CA 92037.

2001-01-01T23:59:59.000Z

333

Electrochemical characterization of a supercapacitor flow cell for power production from salinity gradients  

Science Journals Connector (OSTI)

Salinity gradients could be a great source of energy in the future. Capacitive energy extraction based on Donnan Potential (CDP) is a new technique to directly convert this energy into electricity. CDP uses a supercapacitor-like device combining ion exchange membranes and capacitive materials to adsorb and desorb ions with the Donnan Potential of the membranes as only driving force. The resulting current can be extracted through an external load. In this study, traditional electrochemical techniques: galvanostatic chargedischarge and cyclic voltammetry were used to investigate intrinsic properties of this open system. This study demonstrates the feasibility to characterize the capacitive behavior of the cell in low concentration (0.5M). Presence of membranes, as well as the possibility of having the electrolyte flowing through the cell was investigated. In the studied cell, the presence of membranes showed a limitation by the anion exchange membrane at low current densities but no effect at high current densities. The flow rate did not influence the capacitance of the system either.

Bruno B. Sales; Fei Liu; Olivier Schaetzle; Cees J.N. Buisman; Hubertus V.M. Hamelers

2012-01-01T23:59:59.000Z

334

Thermal Gradient Holes At Northern Basin & Range Region (Pritchett, 2004) |  

Open Energy Info (EERE)

Gradient Holes At Northern Basin & Range Region (Pritchett, 2004) Gradient Holes At Northern Basin & Range Region (Pritchett, 2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Northern Basin & Range Region (Pritchett, 2004) Exploration Activity Details Location Northern Basin and Range Geothermal Region Exploration Technique Thermal Gradient Holes Activity Date Usefulness not useful DOE-funding Unknown Notes NOTE: These are theoretical/computer simulation tests of various methods on eight hypothetical 'model' basing-and-range geothermal systems. "The 300-meter heat flow holes are essentially useless for finding the "hidden" reservoirs. Clearly, the best results are obtained from the SP and MT surveys, with DC resistivity a close third. It is concluded that the best

335

Thermal Gradient Holes At Hawthorne Area (Lazaro, Et Al., 2010) | Open  

Open Energy Info (EERE)

source source History View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Page Edit History Facebook icon Twitter icon » Thermal Gradient Holes At Hawthorne Area (Lazaro, Et Al., 2010) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Hawthorne Area (Lazaro, Et Al., 2010) Exploration Activity Details Location Hawthorne Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness useful DOE-funding Unknown Notes The Navy recently completed a temperature gradient hole (TGH) drilling campaign. Results suggest multiple resources may exist on HAD lands. To further define the shallow resource, the Navy will drill one or two

336

Thermal Gradient Holes At Kilauea East Rift Area (Thomas, 1986) | Open  

Open Energy Info (EERE)

Thermal Gradient Holes At Kilauea East Rift Area (Thomas, 1986) Thermal Gradient Holes At Kilauea East Rift Area (Thomas, 1986) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Kilauea East Rift Area (Thomas, 1986) Exploration Activity Details Location Kilauea East Rift Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness useful DOE-funding Unknown Notes Two separate phases of geothermal exploratory drilling have occurred on the lower East Rift. The first was essentially a wildcat venture with relatively little surface exploratory data having been gathered, whereas the second was initiated after somewhat more geoscience information had been acquired under the Hawaii Geothermal Project. The results of the successful exploratory drilling program on the Kilauea

337

Thermal Gradient Holes At Kilauea Summit Area (Keller, Et Al., 1979) | Open  

Open Energy Info (EERE)

Thermal Gradient Holes At Kilauea Summit Area (Keller, Et Al., 1979) Thermal Gradient Holes At Kilauea Summit Area (Keller, Et Al., 1979) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Kilauea Summit Area (Keller, Et Al., 1979) Exploration Activity Details Location Kilauea Summit Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness useful DOE-funding Unknown Notes A deep borehole was drilled at the summit of Kilauea volcano, Hawaii, between April 6 and July 9, 1973. The hole is located approximately 1 km south of the edge of Halemaumau crater (Figs. 1 and 2), a crater within the summit caldera of the volcano. The total depth of the hole is 1262 m (4141 ft) measured from the derrick floor at an altitude of 1102 m (3616 ft). A description of the drilling program and some of the results obtained have

338

Thermal Gradient Holes At Crump's Hot Springs Area (DOE GTP) | Open Energy  

Open Energy Info (EERE)

source source History View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Page Edit History Facebook icon Twitter icon » Thermal Gradient Holes At Crump's Hot Springs Area (DOE GTP) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Crump's Hot Springs Area (DOE GTP) Exploration Activity Details Location Crump's Hot Springs Geothermal Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness not indicated DOE-funding Unknown Notes 8 wells References (1 January 2011) GTP ARRA Spreadsheet Retrieved from "http://en.openei.org/w/index.php?title=Thermal_Gradient_Holes_At_Crump%27s_Hot_Springs_Area_(DOE_GTP)&oldid=402699"

339

Rapid acquisition of specular and diffuse normal maps from polarized spherical gradient illumination  

Science Journals Connector (OSTI)

We estimate surface normal maps of an object from either its diffuse or specular reflectance using four spherical gradient illumination patterns. In contrast to traditional photometric stereo, the spherical patterns allow normals to be estimated simultaneously ...

Wan-Chun Ma; Tim Hawkins; Pieter Peers; Charles-Felix Chabert; Malte Weiss; Paul Debevec

2007-06-01T23:59:59.000Z

340

Salt Gradient Solar Pond for Solar Heat Collection and Lang Term Storage  

Science Journals Connector (OSTI)

Work is described concerning the instrumentation, thermal modelling and laboratory tests on a salt gradient solar pond to be used for heat collection and storage. A densitameter capable of measuring the salinity....

V. Phillips; P. J. Unsworth; N. A. Al-Saleh

1983-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high gradient wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Morphophysiological adaptation aspects of different Haloxylon aphyllum (Chenopodiaceae) genotypes along a salinity gradient  

Science Journals Connector (OSTI)

The seedlings of Haloxylon aphyllum...from seeds with different genetic characteristics, which were collected in three natural subpopulations along a soil salinity gradient, were investigated. The plants grown un...

E. V. Shuyskaya; E. V. Li; Z. F. Rahmankulova

2014-05-01T23:59:59.000Z

342

Phenanthrene mineralization along a natural salinity gradient in an Urban Estuary, Boston Harbor, Massachusetts  

Science Journals Connector (OSTI)

The effect of varying salinity on phenanthrene and glutamate mineralization was examined in sediments along a natural salinity gradient in an urban tidal river. Mineralization was...14CO2 from sediment slurries d...

Michael P. Shiaris

343

Distributions of picophytoplankton and phytoplankton pigments along a salinity gradient in the Changjiang River Estuary, China  

Science Journals Connector (OSTI)

We investigated the abundance of different picophytoplankton groups and the phytoplankton pigment ratio in relation to environmental factors such as nutrients and suspended solids along a salinity gradient in the...

Baoli Wang; Congqiang Liu; Fushun Wang; Siliang Li

2014-08-01T23:59:59.000Z

344

Massdensity relationship changes along salinity gradient in Suaeda salsa L.  

Science Journals Connector (OSTI)

Whether and why the biomassdensity (MN) scaling relationship varies along environmental gradients were continuously debated in theoretical ecology. In this study, how soil salinity stress affects on the MN sca...

Hao Zhang; Genxuan Wang; Kefeng Zheng; Weiping Zhang

2010-11-01T23:59:59.000Z

345

Changes in the biota of Chany Lake along a salinity gradient  

Science Journals Connector (OSTI)

Relationships among salinity and diversity, abundance, biomass of major ... western Siberia, Russia) are examined across a salinity gradient. As salinity increased from 0.8 to 6.4...?1, the species richness of aq...

Laura M. Kipriyanova; Nadezhda I. Yermolaeva; Dmitry M. Bezmaternykh

2007-02-01T23:59:59.000Z

346

Distribution and speciation of phosphorus along a salinity gradient in intertidal marsh sediments  

Science Journals Connector (OSTI)

We examined forms of solid phosphorus fractions in intertidal marsh sediments along a salinity (022) gradient in a river-dominated estuary and in ... the importance of humic-P decreased with increasing salinity

Claus Paludan; James T. Morris

1999-05-01T23:59:59.000Z

347

Thermodynamic and Energy Efficiency Analysis of Power Generation from Natural Salinity Gradients by Pressure Retarded Osmosis  

Science Journals Connector (OSTI)

The Gibbs free energy of mixing dissipated when fresh river water flows into the sea can be harnessed for sustainable power generation. Pressure retarded osmosis (PRO) is one of the methods proposed to generate power from natural salinity gradients. In ...

Ngai Yin Yip; Menachem Elimelech

2012-04-02T23:59:59.000Z

348

Plasma homeostasis and cloacal urine composition inCrocodylus porosus caught along a salinity gradient  

Science Journals Connector (OSTI)

Juveniles of the Estuarine or Saltwater Crocodile,Crocodylus porosus..., maintain both osmotic pressure and plasma electrolyte homeostasis along a salinity gradient from fresh water to the sea. In...C. porosus in...

Gordon C. Grigg

1981-01-01T23:59:59.000Z

349

Double-Diffusive Intrusions in a Stable Salinity Gradient Heated from Below  

Science Journals Connector (OSTI)

Two-dimensional direct numerical simulations (DNS) are used to investigate the growth and nonlinear equilibration of spatially periodic double-diffusive intrusion for negative vertical temperature Tz salinity Sz gradients, which are ...

Julian Simeonov; Melvin E. Stern

2008-10-01T23:59:59.000Z

350

An innovative approach to heat extraction from a salinity gradient solar pond to enhance overall efficiency.  

E-Print Network [OSTI]

??A solar pond is a simple and low-cost solar collector with long-term thermal storage. It utilizes a large body of salinity gradient water to absorb (more)

Yaakob, Y

2013-01-01T23:59:59.000Z

351

Biodiversity and Structure of Macroinvertebrate Communities Along a Small Permanent Salinity Gradient (Meurthe River, France)  

Science Journals Connector (OSTI)

Changes in the macroinvertebrate community were investigated over 10 months at four sites along a 19km salinity gradient (0.212.60gl?1...) in a sixth-order stream, the Meurthe River, northeastern France. Abio...

Christophe Piscart; Jean-Claude Moreteau; Jean-Nicolas Beisel

2005-11-01T23:59:59.000Z

352

Uncertainty Quantification in Viscous Hypersonic Flows using Gradient Information and Surrogate  

E-Print Network [OSTI]

Uncertainty Quantification in Viscous Hypersonic Flows using Gradient Information and Surrogate models for the purposes of uncertainty quantification within the context of viscous hypersonic flows quantification in hypersonic flows. I. Introduction and Motivation The increasing reliance on numerical

Rumpfkeil, Markus Peer

353

Study of inkjet printing as additive manufacturing process for gradient polyurethane material  

Science Journals Connector (OSTI)

Reactive inkjet printing as additive manufacturing technique is evaluated for generation of gradient ... . This study does not examine the complete additive manufacturing process to build whole 3D objects but...O...

Marco Mller; Quang-Ut Huynh; Eckart Uhlmann; Manfred H. Wagner

2014-03-01T23:59:59.000Z

354

Bell-Plesset effects for an accelerating interface with contiguous density gradients  

SciTech Connect (OSTI)

A Plesset-type treatment [J. Appl. Phys. 25, 96 (1954)] is used to assess the effects of contiguous density gradients at an accelerating spherical classical interface on Rayleigh-Taylor and Bell-Plesset perturbation growth. Analytic expressions are obtained that describe enhanced Rayleigh-Taylor instability growth from contiguous density gradients aligned with the acceleration and which increase the effective Atwood number of the perturbed interface. A new pathway for geometric amplification of surface perturbations on an accelerating interface with contiguous density gradients is identified. A resonance condition between the density-gradient scalelength and the radius of the interface is also predicted based on a linearized analysis of Bernoulli's equation, potentially leading to enhanced perturbation growth. Comparison of the analytic treatment with detailed two-dimensional single-mode growth-factor simulations shows good agreement for low-mode numbers where the effects of spherical geometry are most manifested.

Amendt, P

2005-12-20T23:59:59.000Z

355

Approximating the solar/stellar energy generation rate, luminosity gradient, and the hydrogen content  

Science Journals Connector (OSTI)

In this paper we wish to develop an analytical technique for modelling the energy generation rate and the luminosity gradient for ... 1989) we derive dimensionless variables for the energy generation rate and lum...

John F. Doorish

1994-04-01T23:59:59.000Z

356

Gradient analysis of landscape spatial and temporal pattern changes in Beijing metropolitan area  

Science Journals Connector (OSTI)

The gradient based landscape metrics analysis is now widely used to study the landscape pattern changes in respond to the urbanization. In order to discover the trend of spatio-temporal changes in Beijing metr...

YeTao Yang; QiMing Zhou; JianYa Gong; YingYing Wang

2010-05-01T23:59:59.000Z

357

Thermal Gradient Holes At Twenty-Nine Palms Area (Page, Et Al., 2010) |  

Open Energy Info (EERE)

Thermal Gradient Holes At Twenty-Nine Palms Thermal Gradient Holes At Twenty-Nine Palms Geothermal Area (Page, Et Al., 2010) Exploration Activity Details Location Twenty-Nine Palms Geothermal Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness useful DOE-funding Unknown Notes From November 2008 to March 2009, Seabees from the Naval Construction Division (NCD) successfully completed fivetemperature gradient holes for the GPO. Samples taken from each hole were similar in nature; mixtures of sand and conglomerates with the occasional granite sections were typically encountered. Each hole varied slightly in depth, ranging from 600ft to 1,000ft; however, each hole has been completed to acceptable standards of the GPO. Upon completion of drilling, 3" metal tubing was inserted to

358

Thermal Gradient Holes At Twenty-Nine Palms Area (Sabin, Et Al., 2010) |  

Open Energy Info (EERE)

Thermal Gradient Holes At Twenty-Nine Palms Area (Sabin, Et Al., 2010) Thermal Gradient Holes At Twenty-Nine Palms Area (Sabin, Et Al., 2010) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Twenty-Nine Palms Geothermal Area (Sabin, Et Al., 2010) Exploration Activity Details Location Twenty-Nine Palms Geothermal Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness useful DOE-funding Unknown Notes The first and only Seabee drilling project was the installation of five TGHs at the Camp Wilson region of the MCAGCC Marine base near Twenty-Nine Palms, CA. While the program was a success and GPO identified an anomaly where a deep, slim hole is to be drilled in June, 2010, the Seabee rig was sent oversees soon after drilling was completed. If/when another rig

359

Thermal Gradient Holes At Fish Lake Valley Area (DOE GTP) | Open Energy  

Open Energy Info (EERE)

source source History View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Page Edit History Facebook icon Twitter icon » Thermal Gradient Holes At Fish Lake Valley Area (DOE GTP) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Fish Lake Valley Area (DOE GTP) Exploration Activity Details Location Fish Lake Valley Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness not indicated DOE-funding Unknown Notes 2 wells References (1 January 2011) GTP ARRA Spreadsheet Retrieved from "http://en.openei.org/w/index.php?title=Thermal_Gradient_Holes_At_Fish_Lake_Valley_Area_(DOE_GTP)&oldid=511222" Categories:

360

Thermal Gradient Holes At Lightning Dock Area (Warpinski, Et Al., 2004) |  

Open Energy Info (EERE)

Thermal Gradient Holes At Lightning Dock Area Thermal Gradient Holes At Lightning Dock Area (Warpinski, Et Al., 2004) Exploration Activity Details Location Lightning Dock Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness not indicated DOE-funding Unknown Notes The awardee conducted seismic, gravity, resistivity, and airborne magnetic surveys, drilled temperature-gradient wells, and selected a location for a test well (52-7). The test well was drilled to a total depth of 770 m during 2003. Maximum temperatures approached 140degrees C and a short flow test suggested that a production well could be drilled to 600 m and produce economic volumes of 130-140degrees C fluid. A final assessment of the resource is currently being performed. References N. R. Warpinski, A. R. Sattler, R. Fortuna, D. A. Sanchez, J.

Note: This page contains sample records for the topic "high gradient wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Thermal Gradient Holes At Nw Basin & Range Region (Pritchett, 2004) | Open  

Open Energy Info (EERE)

Thermal Gradient Holes At Nw Basin & Range Region (Pritchett, 2004) Thermal Gradient Holes At Nw Basin & Range Region (Pritchett, 2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Nw Basin & Range Region (Pritchett, 2004) Exploration Activity Details Location Northwest Basin and Range Geothermal Region Exploration Technique Thermal Gradient Holes Activity Date Usefulness not useful DOE-funding Unknown Notes NOTE: These are theoretical/computer simulation tests of various methods on eight hypothetical 'model' basing-and-range geothermal systems. "The 300-meter heat flow holes are essentially useless for finding the "hidden" reservoirs. Clearly, the best results are obtained from the SP and MT surveys, with DC resistivity a close third. It is concluded that the best

362

Influence of surface heating on the boundary layer stability of flows with favorable pressure gradients  

E-Print Network [OSTI]

INFLUENCE OF SURFACE HEATING ON THE BOUNDARY LAYER STABILITY OF FLOWS WITH FAVORABI E PRESSURE GRADIENTS A Thesis by DAVID BRIAN LANDRUM Submitted to the Graduate College of Texas AAM University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE August 1986 Major Subject: Aerospace Engineering INFLUENCE OF SURFACE HEATING ON THE BOUNDARY LAYER STABILITY OF FLOWS WITH FAVORABLE PRESSURE GRADIENTS A Thesis by DAVID BRIAN LANDRUM Approved as to style and content...

Landrum, David Brian

2012-06-07T23:59:59.000Z

363

Poblano v1.0 : a Matlab toolbox for gradient-based optimization.  

SciTech Connect (OSTI)

We present Poblano v1.0, a Matlab toolbox for solving gradient-based unconstrained optimization problems. Poblano implements three optimization methods (nonlinear conjugate gradients, limited-memory BFGS, and truncated Newton) that require only first order derivative information. In this paper, we describe the Poblano methods, provide numerous examples on how to use Poblano, and present results of Poblano used in solving problems from a standard test collection of unconstrained optimization problems.

Dunlavy, Daniel M.; Acar, Evrim (Sandia National Laboratories, Livermore, CA); Kolda, Tamara Gibson (Sandia National Laboratories, Livermore, CA)

2010-03-01T23:59:59.000Z

364

Faster Time Response by the Use of Wire Electrodes in Capacitive Salinity Gradient Energy Systems  

Science Journals Connector (OSTI)

Comparing salinity gradient power to other ocean power sources, such as wind, ocean currents, wave, tidal streams, and thermal gradients, it is supreme partly in that it has the second largest power potential, but foremost because it is focused at river deltas (rather than being distributed over the ocean areas across the world). ... We also studied the asymmetric behavior of response time in concentrated saline solution and dilute saline solution that is reported for our branch of technologies. ... solns. of different salinities. ...

Odne S. Burheim; Fei Liu; Bruno B. Sales; Olivier Schaetzle; Cees J. N. Buisman; Hubertus V. M. Hamelers

2012-08-28T23:59:59.000Z

365

The effects of an ambient salinity gradient on the dilution of dense brine jets  

E-Print Network [OSTI]

THE EFFECTS OF AN AMBIENT SALINITY GRADIENT ON THE DILUTION OF DENSE BRINE JETS A Thesis by GARY WAYNE MCCULLOUGH Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER... OF SCIENCE December 1986 Major Subject: Ocean Engineering THE EFFECTS OF AN AMBIENT SALINITY GRADIENT ON THE DILUTION OF DENSE BRINE JETS A Thesis by GARY NAYNE MCCULLOUGH Approved as to style and content by: Robert E. Randall (Chair of Committee...

McCullough, Gary Wayne

2012-06-07T23:59:59.000Z

366

Effect of pressure gradient on the drag reduction performance of two and three dimensional riblets  

E-Print Network [OSTI]

Integral Parameters . 4. 2 Law of the Wall Profiles 4. 3 Pressure Gradient Parameters 4. 4 Preston Tube Measurements 4. 5 Roughness Function 4. 6 Growth of the Internal Layer 4. 7 Turbulence Measurements 4. 7. 1 Turbulence intensity 4. 7. 2 Third.... 4 Spectra for favorable pressure gradient 4. 8. 5 Roughness effects on the bursting process V CONCLUSION . REFERENCES APPENDIX A APPENDIX B 50 50 51 94 134 175 177 180 183 . . 185 VITA . . 210 LIST OF FIGURES Figure 1. Proportions...

Hall, Aaron Chenault

1991-01-01T23:59:59.000Z

367

Thermal Gradient Holes At Fenton Hill HDR Geothermal Area (Purtymun...  

Open Energy Info (EERE)

Valles caldera in order to locate an of high heat flow that would serve as a favorable test site for the HDR concept. Notes Data from these wells are report in Reiter et al....

368

Applications of salinity gradient solar technologies in the Southwest -- An overview  

SciTech Connect (OSTI)

This paper is an overview of recent applications of salinity gradient solar technologies (SGST) in the Southwest and especially in the State of Texas. SGST is a generic title for using a salinity gradient in a body of water to suppress convection and collect solar energy for a desired application, for example, salinity gradient solar ponds. Following initial work in the early 1980s at the El Paso Solar Pond project and funding of the Texas Solar Pond Consortium by the State of Texas and the Bureau of Reclamation, several applications involving the use of salinity gradient solar technologies have emerged. These applications include a biomass waste to energy project using heat from a solar pond at Bruce Foods Corporation; an industrial process heat application for sodium sulfate mining near Seagraves, Texas; overwintering thermal refuges for mariculture in Palacios, Texas; a potential salt management project on the Brazos River near Abilene, Texas; and use of solar ponds for brine disposal at a water desalting project in a small colonia east of El Paso. This paper discusses salinity gradient solar technology requirements and the abundance of resources available in Texas and the Southwest which makes this an attractive location for the commercial development of salinity gradient projects. Barriers to development as well as catalysts are discussed before a brief overview of the projects listed above is provided.

Swift, A.H.P.; Lu, H. [Univ. of Texas, El Paso, TX (United States)

1996-12-31T23:59:59.000Z

369

Critical temperature gradient length signatures in heat wave propagation across internal transport barriers in the Joint European Torus  

SciTech Connect (OSTI)

New results on electron heat wave propagation using ion cyclotron resonance heating power modulation in the Joint European Torus (JET) [P. H. Rebut et al., Nucl. Fusion 25, 1011 (1985)] plasmas characterized by internal transport barriers (ITBs) are presented. The heat wave generated outside the ITB, and traveling across it, always experiences a strong damping in the ITB layer, demonstrating a low level of transport and loss of stiffness. In some cases, however, the heat wave is strongly inflated in the region just outside the ITB, showing features of convective-like behavior. In other cases, a second maximum in the perturbation amplitude is generated close to the ITB foot. Such peculiar types of behavior can be explained on the basis of the existence of a critical temperature gradient length for the onset of turbulent transport. Convective-like features appear close to the threshold (i.e., just outside the ITB foot) when the value of the threshold is sufficiently high, with a good match with the theoretical predictions for the trapped electron mode threshold. The appearance of a second maximum is due to the oscillation of the temperature profile across the threshold in the case of a weak ITB. Simulations with an empirical critical gradient length model and with the theory based GLF23 [R. E. Waltz et al., Phys. Plasmas, 4, 2482 (1997)] model are presented. The difference with respect to previous results of cold pulse propagation across JET ITBs is also discussed.

Casati, Alessandro [Istituto di Fisica del Plasma 'P. Caldirola', Associazione Euratom-ENEA-CNR, Via Cozzi 53, 20125 Milano (Italy); Dipartimento di Ingegneria Nucleare, Politecnico di Milano, Via Ponzio 34/3, 20133 Milano (Italy); Mantica, P. [Istituto di Fisica del Plasma 'P. Caldirola', Associazione Euratom-ENEA-CNR, Via Cozzi 53, 20125 Milano (Italy); Eester, D. van [LPP-ERM/KMS, Association Euratom-Belgian State, TEC, B-1000 Brussels (Belgium); Hawkes, N.; De Vries, P. [Culham Science Centre, EURATOM/UKAEA Fusion Association, Abingdon OX14 3DB (United Kingdom); Imbeaux, F.; Joffrin, E. [Association Euratom-CEA, CEA-DSM-DRFC Cadarache, 13108, St. Paul-lez-Durance Cedex (France); Marinoni, A. [Association Euratom-Confederation Suisse, CRPP, EPFL, CH 1015, Lausanne (Switzerland); Ryter, F. [Max-Planck Insitut fur Plasmaphysik, Euratom Association, 85748 Garching (Germany); Salmi, A. [Helsinki University of Technology, Association Euratom-TEKES, P.O. Box 2200 (Finland); Tala, T. [Association Euratom-TEKES, VTT, P.O. Box 1000, FIN-02044 VTT (Finland)

2007-09-15T23:59:59.000Z

370

Controllable high-quality electron beam generation by phase slippage effect in layered targets  

E-Print Network [OSTI]

The bubble structure generated by laser and plasma interactions changes in size depending on the local plasma density. The self injection electrons position with respect to wakefield can be controlled by tailoring the longitudinal plasma density. A regime to enhance the energy of the wakefield accelerated electrons and improve the beam quality is proposed and achieved using layered plasmas with increasing densities. Both the wakefield size and the electron bunch duration are significantly contracted in this regime. The electrons remain in the strong acceleration phase of the wakefield while their energy spread decreases because of their tight spatial distribution. An electron beam of 0.5GeV with less than 0.01 energy spread is obtained through 2.5D PIC simulations.

Yu, Q; Li, X F; Huang, S; Zhang, F; Kong, Q; Ma, Y Y; Kawata, S

2014-01-01T23:59:59.000Z

371

2009_1112 HPC requirements workshop.pptx  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

simulation of laser wakefield simulation of laser wakefield particle acceleration - M558 C.G.R. Geddes (M558 lead) LOASIS program, LBNL , http://loasis.lbl.gov W.P. Leemans, Program head; E. Esarey deputy & theory head C. Benedetti, M. Chen, E. Cormier-Michel, E. Esarey, C.B. Schroeder Tech-X, http://www.txcorp.com D.L. Bruhwiler, J.R. Cary, B.M. Cowan, C. Nieter, K. Paul, V. Ranjabar Oxford W. Andreas, S. Bajlekov, N. Bourgeois, T. Ibbotson, S.M. Hooker 1 1 NA-22/Nonproliferation R&D *cgrgeddes@lbl.gov Simulations support LOASIS experiments and BELLA design Outline  BELLA project + collaborators: High gradient laser - plasma accelerators  Quantitative modeling of self-trapped low ΔE experiments 1 using new numerics 2  Physics of controlled trapping for low momentum spread bunches: downramp

372

OPTICAL-NEAR-INFRARED COLOR GRADIENTS AND MERGING HISTORY OF ELLIPTICAL GALAXIES  

SciTech Connect (OSTI)

It has been suggested that merging plays an important role in the formation and the evolution of elliptical galaxies. While gas dissipation by star formation is believed to steepen metallicity and color gradients of the merger products, mixing of stars through dissipation-less merging (dry merging) is believed to flatten them. In order to understand the past merging history of elliptical galaxies, we studied the optical-near-infrared (NIR) color gradients of 204 elliptical galaxies. These galaxies are selected from the overlap region of the Sloan Digital Sky Survey (SDSS) Stripe 82 and the UKIRT Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS). The use of optical and NIR data (g, r, and K) provides large wavelength baselines, and breaks the age-metallicity degeneracy, allowing us to derive age and metallicity gradients. The use of the deep SDSS Stripe 82 images makes it possible for us to examine how the color/age/metallicity gradients are related to merging features. We find that the optical-NIR color and the age/metallicity gradients of elliptical galaxies with tidal features are consistent with those of relaxed ellipticals, suggesting that the two populations underwent a similar merging history on average and that mixing of stars was more or less completed before the tidal features disappeared. Elliptical galaxies with dust features have steeper color gradients than the other two types, even after masking out dust features during the analysis, which can be due to a process involving wet merging. More importantly, we find that the scatter in the color/age/metallicity gradients of the relaxed and merging feature types decreases as their luminosities (or masses) increase at M > 10{sup 11.4} M{sub Sun} but stays large at lower luminosities. Mean metallicity gradients appear nearly constant over the explored mass range, but a possible flattening is observed at the massive end. According to our toy model that predicts how the distribution of metallicity gradients changes as a result of major dry merging, the mean metallicity gradient should flatten by 40% and its scatter becomes smaller by 80% per a mass-doubling scale if ellipticals evolve only through major dry merger. Our result, although limited by a number statistics at the massive end, is consistent with the picture that major dry merging is an important mechanism for the evolution for ellipticals at M > 10{sup 11.4} M{sub Sun }, but is less important at the lower mass range.

Kim, Duho; Im, Myungshin [Center for the Exploration of the Origin of the Universe (CEOU), Astronomy Program, Department of Physics and Astronomy, Seoul National University, 1 Gwanak-rho, Gwanak-gu, Seoul 151-742 (Korea, Republic of)] [Center for the Exploration of the Origin of the Universe (CEOU), Astronomy Program, Department of Physics and Astronomy, Seoul National University, 1 Gwanak-rho, Gwanak-gu, Seoul 151-742 (Korea, Republic of)

2013-04-01T23:59:59.000Z

373

Method to create gradient index in a polymer  

DOE Patents [OSTI]

Novel photo-writable and thermally switchable polymeric materials exhibit a refractive index change of .DELTA.n.gtoreq.1.0 when exposed to UV light or heat. For example, lithography can be used to convert a non-conjugated precursor polymer to a conjugated polymer having a higher index-of-refraction. Further, two-photon lithography can be used to pattern high-spatial frequency structures.

Dirk, Shawn M; Johnson, Ross Stefan; Boye, Robert; Descour, Michael R; Sweatt, William C; Wheeler, David R; Kaehr, Bryan James

2014-10-14T23:59:59.000Z

374

The long range migration of hydrogen through Zircaloy in response to tensile and compressive stress gradients  

SciTech Connect (OSTI)

Zircaloy-4, which is used widely as a core structural material in pressurized water reactors (PWRs), picks up hydrogen during service. Hydrogen solubility in Zircaloy-4 is low and zirconium hydride phases precipitate after the Zircaloy-4 lattice becomes supersaturated with hydrogen. These hydrides embrittle the Zircaloy-4, degrading its mechanical performance as a structural material. Because hydrogen can move rapidly through the Zircaloy-4 lattice, the potential exists for large concentrations of hydride to accumulate in local regions of a Zircaloy component remote from its point of entry into the component. Much has been reported in the literature regarding the long range migration of hydrogen through Zircaloy under concentration gradients and temperature gradients. Relatively little has been reported, however, regarding the long range migration of hydrogen under stress gradients. This paper presents experimental results regarding the long range migration of hydrogen through Zircaloy in response to both tensile and compressive stress gradients. The importance of this driving force for hydrogen migration relative to concentration and thermal gradients is discussed.

Kammenzind, B.F.; Berquist, B.M.; Bajaj, R.; Kreyns, P.H.; Franklin, D.G.

1998-11-01T23:59:59.000Z

375

Moorland pools as refugia for endangered species characteristic of raised bog gradients  

Science Journals Connector (OSTI)

In intact raised bog landscapes transitions from ombrotrophic into minerotrophic conditions occur. These gradients are lost from many bogs due to peat harvesting and drainage, and are difficult to restore. To determine which endangered species are characteristic of pristine raised bog gradients and their current status in degraded bogs, plants and macroinvertebrates were surveyed in Estonian intact raised bogs and Dutch degraded bog remnants. Dutch national distribution data were used to determine whether communities with these species occurred outside bog habitats. Water chemistry data were used to describe associated environmental conditions. Intact bog gradients were the preferred habitat for six plant species and fifteen macroinvertebrate species, all of which are endangered. In degraded bogs these species were scarce or not recorded. In intact bogs these species lived at sites where runoff from the bog massif came into contact with regional ground water resulting in a gradient in pH, alkalinity, Ca, Fe and ionic ratio. Analysis of Dutch national distribution data revealed aggregations of these endangered species in moorland pools. These pools contained water chemistry gradients similar to those found in pristine bogs, which occurred at sites were groundwater seepage and stream water came in contact. In the past, stream water has been used to increase pH and trophic status of moorland pools facilitating fisheries. Today, this practice offers a conservation strategy for the protection of endangered species for which no short-term alternatives are available.

Hein H. van Kleef; Gert-Jan A. van Duinen; Wilco C.E.P. Verberk; Rob S.E.W. Leuven; Gerard van der Velde; Hans Esselink

2012-01-01T23:59:59.000Z

376

High-Sensitivity Analysis of Human Plasma Proteome by Immobilized Isoelectric Focusing Fractionation Coupled to Mass  

E-Print Network [OSTI]

High-Sensitivity Analysis of Human Plasma Proteome by Immobilized Isoelectric Focusing of complex biological samples. Keywords: plasma · immobilized pH gradients · isoelectric focusing of Sciences, Shanghai, 200031, China Received December 24, 2004 Immobilized pH gradients isoelectric focusing

Tian, Weidong

377

Scattering polarization in the CaII Infrared Triplet with Velocity Gradients  

E-Print Network [OSTI]

Magnetic field topology, thermal structure and plasma motions are the three main factors affecting the polarization signals used to understand our star. In this theoretical investigation, we focus on the effect that gradients in the macroscopic vertical velocity field have on the non-magnetic scattering polarization signals, establishing the basis for general cases. We demonstrate that the solar plasma velocity gradients have a significant effect on the linear polarization produced by scattering in chromospheric spectral lines. In particular, we show the impact of velocity gradients on the anisotropy of the radiation field and on the ensuing fractional alignment of the CaII levels, and how they can lead to an enhancement of the zero-field linear polarization signals. This investigation remarks the importance of knowing the dynamical state of the solar atmosphere in order to correctly interpret spectropolarimetric measurements, which is important, among other things, for establishing a suitable zero field refe...

Carlin, E S; Ramos, A Asensio; Bueno, J Trujillo

2012-01-01T23:59:59.000Z

378

Thermal Gradient Holes At Upper Hot Creek Ranch Area (Benoit & Blackwell,  

Open Energy Info (EERE)

Hot Creek Ranch Area (Benoit & Blackwell, Hot Creek Ranch Area (Benoit & Blackwell, 2006) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Upper Hot Creek Ranch Area (Benoit & Blackwell, 2006) Exploration Activity Details Location Upper Hot Creek Ranch Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness not useful DOE-funding Unknown Notes Ten temperature gradient holes up to 500' deep were initially planned but higher than anticipated drilling and permitting costs within a fixed budget reduced the number of holes to five. Four of the five holes drilled to depths of 300 to 400' encountered temperatures close to the expected regional thermal background conditions. These four holes failed to find any evidence of a large thermal anomaly surrounding the UHCR hot springs. The

379

Thermal Gradient Holes At Chocolate Mountains Area (Sabin, Et Al., 2010) |  

Open Energy Info (EERE)

Thermal Gradient Holes At Chocolate Mountains Area Thermal Gradient Holes At Chocolate Mountains Area (Sabin, Et Al., 2010) Exploration Activity Details Location Chocolate Mountains Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness not indicated DOE-funding Unknown Notes In lieu of Seabee TGH drilling, GPO awarded a large IDIQ TGH drilling contract in December, 2009. Over the next two years, 90 500-ft TGHs will be installed at select sites in California and Nevada. Interim data from this campaign are already available for the Chocolate Mountains and Hawthorne. Results of these programs can be found in the Chocolate Mountains and Hawthorne papers also available in this volume. References Andrew Sabin, S. Bjornstad, M. Lazaro, D. Meade, C. Page, S. Alm, A. Tiedeman, W. C. Huang (2010) Navy's Geothermal Program Office: Overview

380

PLASMA WAKEFIELD ACCELERATION UTILIZING MULTIPLE ELECTRON BUNCHES  

E-Print Network [OSTI]

. Yakimenko, Brookhaven National Lab., Upton, NY W. D. Kimura, STI Optronics, Bellevue, WA Abstract We

Brookhaven National Laboratory

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While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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381

Density gradient free electron collisionally excited X-ray laser  

DOE Patents [OSTI]

An operational X-ray laser (30) is provided that amplifies 3p-3s transition X-ray radiation along an approximately linear path. The X-ray laser (30) is driven by a high power optical laser. The driving line focused optical laser beam (32) illuminates a free-standing thin foil (34) that may be associated with a substrate (36) for improved structural integrity. This illumination produces a generally cylindrically shaped plasma having an essentially uniform electron density and temperature, that exists over a long period of time, and provides the X-ray laser gain medium. The X-ray laser (30) may be driven by more than one optical laser beam (32, 44). The X-ray laser (30) has been successfully demonstrated to function in a series of experimental tests.

Campbell, Edward M. (Pleasanton, CA); Rosen, Mordecai D. (Berkeley, CA)

1989-01-01T23:59:59.000Z

382

Density gradient free electron collisionally excited x-ray laser  

DOE Patents [OSTI]

An operational x-ray laser is provided that amplifies 3p-3s transition x-ray radiation along an approximately linear path. The x-ray laser is driven by a high power optical laser. The driving line focused optical laser beam illuminates a free-standing thin foil that may be associated with a substrate for improved structural integrity. This illumination produces a generally cylindrically shaped plasma having an essentially uniform electron density and temperature, that exists over a long period of time, and provides the x-ray laser gain medium. The x-ray laser may be driven by more than one optical laser beam. The x-ray laser has been successfully demonstrated to function in a series of experimental tests.

Campbell, E.M.; Rosen, M.D.

1984-11-29T23:59:59.000Z

383

Exploring approximations to the GW self-energy ionic gradients  

E-Print Network [OSTI]

The accuracy of the many-body perturbation theory GW formalism to calculate electron-phonon coupling matrix elements has been recently demonstrated in the case of a few important systems. However, the related computational costs are high and thus represent strong limitations to its widespread application. In the present study, we explore two less demanding alternatives for the calculation of electron-phonon coupling matrix elements on the many-body perturbation theory level. Namely, we test the accuracy of the static Coulomb-hole plus screened-exchange (COHSEX) approximation and further of the constant screening approach, where variations of the screened Coulomb potential W upon small changes of the atomic positions along the vibrational eigenmodes are neglected. We find this latter approximation to be the most reliable, whereas the static COHSEX ansatz leads to substantial errors. Our conclusions are validated in a few paradigmatic cases: diamond, graphene and the C60 fullerene. These findings open the way f...

Faber, C; Attaccalite, C; Cannuccia, E; Duchemin, I; Deutsch, T; Blase, X

2015-01-01T23:59:59.000Z

384

Thermal Gradient Holes At Lake City Hot Springs Area (Warpinski, Et Al.,  

Open Energy Info (EERE)

2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Lake City Hot Springs Area (Warpinski, Et Al., 2004) Exploration Activity Details Location Lake City Hot Springs Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness not indicated DOE-funding Unknown Notes The Lake City site, which is located in far northeastern California, consists of a previously identified geothermal site that has been explored with both geophysics and drilling (Hedel, 1981), but has not been characterized adequately to allow accurate siting or drilling of production wells. Some deep wells, several seismic lines, limited gravity surveys, and geochemical and geological studies have suggested that the geothermal

385

Non-preconditioned conjugate gradient on cell and FPCA-based hybrid supercomputer nodes  

SciTech Connect (OSTI)

This work presents a detailed implementation of a double precision, Non-Preconditioned, Conjugate Gradient algorithm on a Roadrunner heterogeneous supercomputer node. These nodes utilize the Cell Broadband Engine Architecture{trademark} in conjunction with x86 Opteron{trademark} processors from AMD. We implement a common Conjugate Gradient algorithm, on a variety of systems, to compare and contrast performance. Implementation results are presented for the Roadrunner hybrid supercomputer, SRC Computers, Inc. MAPStation SRC-6 FPGA enhanced hybrid supercomputer, and AMD Opteron only. In all hybrid implementations wall clock time is measured, including all transfer overhead and compute timings.

Dubois, David H [Los Alamos National Laboratory; Dubois, Andrew J [Los Alamos National Laboratory; Boorman, Thomas M [Los Alamos National Laboratory; Connor, Carolyn M [Los Alamos National Laboratory

2009-03-10T23:59:59.000Z

386

paper.dvi  

Office of Scientific and Technical Information (OSTI)

first two kilometers of the SLAC linac to generate high energy, high density electron beams for advanced accelerator experiments, with an emphasis on plasma wakefield...

387

An improved parallel hybrid bi-conjugate gradient method suitable for distributed parallel computing  

Science Journals Connector (OSTI)

An improved parallel hybrid bi-conjugate gradient method (IBiCGSTAB(2) method, in brief) for solving large sparse linear systems with nonsymmetric coefficient matrices is proposed for distributed parallel environments. The method reduces five global ... Keywords: Distributed parallel environments, Global communication, IBiCGSTAB(2) method, Krylov subspace method, Sparse nonsymmetric linear system

Tong-Xiang Gu; Xian-Yu Zuo; Xing-Ping Liu; Pei-Lu Li

2009-04-01T23:59:59.000Z

388

Doxorubicin physical state in solution and inside liposomes loaded via a pH gradient  

E-Print Network [OSTI]

R. Perkins aY * a The Liposome Company, Inc., One Research Way, Princeton, NJ 08540, USA b Department of Physics, Cornell University, Ithaca, NY 14853, USA Received 26 May 1998; accepted 9 September/cholesterol liposomes that were loaded via a transmembrane pH gradient. Using cryogenic electron microscopy (cryo-EM) we

Gruner, Sol M.

389

Electron velocity distribution function in a plasma with temperature gradient and in the presence of suprathermal  

E-Print Network [OSTI]

Electron velocity distribution function in a plasma with temperature gradient and in the presence of suprathermal electrons: application to incoherent-scatter plasma lines P. Guio1 , J. Lilensten2 , W. Kofman2 arbitrary velocity distribution function with cylindrical symmetry along the magnetic ®eld. The electron

Paris-Sud XI, Université de

390

One dimensional electron spin imaging for single spin detection and manipulation using a gradient field  

E-Print Network [OSTI]

Fabrications.............................................................................. 71 1. Design of Microwave Strip-lines and Magnetic Field Gradient Coil 71 x CHAPTER... with microwave power of 7dBm at 2.87GHz was applied ................................................................................. 70 2.29 a, Top view of the simulation structure for the 50Ohm coplanar microwave striplines. b, Cross-section view...

Shin, Chang-Seok

2009-05-15T23:59:59.000Z

391

Nonlinear root-derived carbon sequestration across a gradient of nitrogen and phosphorous deposition  

E-Print Network [OSTI]

Nonlinear root-derived carbon sequestration across a gradient of nitrogen and phosphorous sequestration of plant-carbon (C) inputs to soil may mitigate rising atmo- spheric carbon dioxide (CO2) concentrations and related climate change but how this sequestration will respond to anthropogenic nitrogen (N

Fierer, Noah

392

Power Grid Analysis Using a Flexible Conjugate Gradient Algorithm with Sparsification  

E-Print Network [OSTI]

Power Grid Analysis Using a Flexible Conjugate Gradient Algorithm with Sparsification Peter power grid analysis. The algorithm allows changing preconditioners and sparsification of the search and sparsification. The algorithm is applied to a number of realistic power grid examples. I. INTRODUCTION The design

Freund, Roland W.

393

Double-hybrid density-functional theory with meta-generalized-gradient approximations  

E-Print Network [OSTI]

Double-hybrid density-functional theory with meta-generalized-gradient approximations Sidi Ould-parameter double-hybrid density-functional theory [K. Sharkas, J. Toulouse, and A. Savin, J. Chem. Phys. 134 of the most accurate approximations for electronic-structure calculations within density- functional theory

Paris-Sud XI, Université de

394

Manufacture of gradient micro-structures of magnesium alloys using two stage extrusion dies  

SciTech Connect (OSTI)

This paper aims to manufacture magnesium alloy metals with gradient micro-structures using hot extrusion process. The extrusion die was designed to have a straight channel part combined with a conical part. Materials pushed through this specially-designed die generate a non-uniform velocity distribution at cross sections inside the die and result in different strain and strain rate distributions. Accordingly, a gradient microstructure product can be obtained. Using the finite element analysis, the forming temperature, effective strain, and effective strain rate distributions at the die exit were firstly discussed for various inclination angles in the conical die. Then, hot extrusion experiments with a two stage die were conducted to obtain magnesium alloy products with gradient micro-structures. The effects of the inclination angle on the grain size distribution at cross sections of the products were also discussed. Using a die of an inclination angle of 15, gradient micro-structures of the grain size decreasing gradually from 17 ?m at the center to 4 ?m at the edge of product were achieved.

Hwang, Yeong-Maw; Huang, Tze-Hui [Department of Mechanical and Electro-Mechanical Engineering, National Sun Yat-Sen University, No. 70, Lien-Hai Rd., Kaohsiung, 804, Taiwan (China); Alexandrov, Sergei [Institute for Problems in Mechanics, Russian Academy of Sciences, Moscow (Russian Federation); Naimark, Oleg Borisovich [Institute of Continuous Media Mechanics, Russian Academy of Sciences, Perm (Russian Federation); Jeng, Yeau-Ren [Department of Mechanical Engineering and Advanced Institute of Manufacturing with High-tech Innovations, National Chung Cheng University, Ming-Hsiung, Chia-Yi 621, Taiwan (China)

2013-12-16T23:59:59.000Z

395

Top hole drilling with dual gradient technology to control shallow hazards  

E-Print Network [OSTI]

3.2 Riserless Dual Gradient Drilling Technology Description .........................36 3.2.1 Kick Detection.............................................................................37 3.2.2 Well Control ?Modified Driller?s Method... ? PRESSURE @ TOP OF KICK GRAPHS ? SET #1..........................140 ix Page APPENDIX F ? PRESSURE @ TOP OF KICK GRAPHS ? SET #2 ..........................159 VITA...

Elieff, Brandee Anastacia Marie

2006-10-30T23:59:59.000Z

396

The influence of surface tension gradients on drop coalescence Franois Blanchette,1  

E-Print Network [OSTI]

The influence of surface tension gradients on drop coalescence François Blanchette,1 Laura Messio,2 to elucidating the influence on the coalescence process of a surface tension difference between drop coalescence may occur. Three distinct regimes, depending on the reservoir to drop surface tension ratio, R

Bush, John W.M.

397

VIDEO FINGERPRINTING BASED ON CENTROIDS OF GRADIENT ORIENTATIONS Sunil Lee and Chang D. Yoo  

E-Print Network [OSTI]

VIDEO FINGERPRINTING BASED ON CENTROIDS OF GRADIENT ORIENTATIONS Sunil Lee and Chang D. Yoo Dept the video signal. The goal of a video fingerprinting sys- tem is to judge whether two videos have the same contents by measuring distance between fingerprints extracted from the videos. In this paper, a novel video

Yoo, Chang D.

398

Inverted metamorphic sequence in the Sikkim Himalayas: crystallization history, PT gradient and implications  

E-Print Network [OSTI]

Inverted metamorphic sequence in the Sikkim Himalayas: crystallization history, P­T gradient The metapelitic rocks of the Sikkim Himalayas show an inverted metamorphic sequence (IMS) of the complete to be capable of explaining these observations. Key words: Himalayas; inverted Barrovian zones; main central

Ganguly, Jibamitra

399

Nutrient Limitation across a salinity gradient of Martha's Vineyard Coastal Ponds Emily S Rogers  

E-Print Network [OSTI]

Nutrient Limitation across a salinity gradient of Martha's Vineyard Coastal Ponds Emily S Rogers and their respective salinities were Long Cove Pond, 1ppt, Little Jobs Pond, 4ppt, Jobs Neck Pond, 9ppt, Chilmark Pond. There was a strong correlation between ammonium limitation and salinity. There was very little response

Vallino, Joseph J.

400

Transient hydrodynamic, heat and mass transfer in a salinity gradient solar pond: A numerical study  

Science Journals Connector (OSTI)

Abstract The impoverishment of our planet in non-renewable energies has incited researchers to design salinity gradient solar ponds to collect and store solar energy at a lower cost. It is in this context that the present research work lies to focus on the numerical study of the transient hydrodynamic, heat and mass transfer in a salinity gradient solar pond. The problem is tackled using the dimensionless governing equations of NavierStokes, thermal energy and mass transfer, which are solved numerically by finite-volume method to provide the temperature, concentration and velocity fields in transient regime. The pond is filled with salty water of various salinities to form three zones of salty water: Upper Convective Zone (UCZ), Non-Convective Zone (NCZ) and Lower Convective Zone (LCZ). To prevent convective movements induced by the internal heating of salty water due to solar radiation absorption, a salinity gradient is used in the solar pond. Representative results illustrating the influence of internal Rayleigh number on the thermal performance of the pond and the effect of the aspect ratio on the distribution of temperature and velocity fields in the salinity gradient solar pond (SGSP) are discussed. In addition, results for the transient average temperature of UCZ and LCZ are presented and discussed for various parametric conditions.

Ridha Boudhiaf; Mounir Baccar

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high gradient wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Life history variation of invasive mosquitofish (Gambusia holbrooki) along a salinity gradient  

E-Print Network [OSTI]

Life history variation of invasive mosquitofish (Gambusia holbrooki) along a salinity gradient on ecosystem functioning and several native taxa. Although it has been suggested that salinity limits the invasive success of mosquitofish, there are few studies on how salinity affects its ecology. We examined

García-Berthou, Emili

402

Mixed Aleatory/Epistemic Uncertainty Quantification for Hypersonic Flows via Gradient-Based Optimization  

E-Print Network [OSTI]

Mixed Aleatory/Epistemic Uncertainty Quantification for Hypersonic Flows via Gradient/aleatory uncertainties is demonstrated within the context of hypersonic flows. Specifically, this work focuses in which experimental data is difficult or impossible to obtain, as is the case with hypersonic flows

Anitescu, Mihai

403

Change in biomass of benthic and planktonic algae along a disturbance gradient for 24 Great  

E-Print Network [OSTI]

Change in biomass of benthic and planktonic algae along a disturbance gradient for 24 Great Lakes. The PC1 site score was significantly related to both periphyton and phytoplankton biomass, respectively accounted for 18% of the variation in epiphyton biomass. Periphytic and epiphytic biomass were negatively

McMaster University

404

Measurement of the gradient of the Casimir force between a nonmagnetic sphere and a magnetic plate  

E-Print Network [OSTI]

We measured the gradient of the Casimir force between an Au sphere and a plate made of ferromagnetic metal (Ni). It is demonstrated that the magnetic properties influence the force magnitude. This opens prospective opportunities for the control of the Casimir force in nanotechnology and for obtaining Casimir repulsion by using ferromagnetic dielectrics.

A. A. Banishev; C. -C. Chang; G. L. Klimchitskaya; V. M. Mostepanenko; U. Mohideen

2012-05-04T23:59:59.000Z

405

OnLine IPA Gradient Estimators in Stochastic Continuous Fluid Models  

E-Print Network [OSTI]

On­Line IPA Gradient Estimators in Stochastic Continuous Fluid Models Yorai Wardi # School Perturbation Analysis (IPA) to loss­related and workload­ related metrics in a class of Stochastic Flow Models parameters of interest, such as bu#er size, service rate and inflow rate. The IPA estimators derived

406

On the role of material property gradients in noncontacting thermoelectric NDE  

E-Print Network [OSTI]

On the role of material property gradients in noncontacting thermoelectric NDE Hector Carreon. The thermoelectric power of metals is sensitive to variety of material properties that can affect the measurement the basic appli- cation of thermoelectric materials characterization is metal sorting [1]. However

Nagy, Peter B.

407

Changes in species assemblages and diets of Collembola along a gradient of metal pollution  

E-Print Network [OSTI]

pollution. Keywords: Collembolan communities, Heavy metals, Gut contents 1. Introduction * Corresponding.1016/S0929-1393(02)00134-8 #12;2 Pollution by heavy metals, due to smelter, mining or agricultural the hypothesis that soil animal communities sampled along a gradient of heavy metal pollution show a) shifts

Paris-Sud XI, Université de

408

Capacitive mixing power production from salinity gradient energy enhanced through exoelectrogen-  

E-Print Network [OSTI]

to generate electrical power directly from salinity gradient energy using capacitive electrodes have recently generation and wastewater treatment. Introduction Harnessing the entropic energy released when river water with these capacitive electrodes two different ways: either through changes in membrane potentials due to ion

409

Ab initio calculation of the temperature dependence of the electric field gradient in Be  

Science Journals Connector (OSTI)

Using the orthogonalized-plane-wave procedure, the band structure, Fermi surface, and conduction-electron wave functions of Be have been calculated as a function of temperature. The electric field gradients calculated from first principles obey the T32 behavior and are negative throughout the temperature range studied.

P. Jena and J. Rath

1981-04-15T23:59:59.000Z

410

Using image gradient as a visual feature for visual servoing Eric Marchand, Christophe Collewet  

E-Print Network [OSTI]

Using image gradient as a visual feature for visual servoing Eric Marchand, Christophe Collewet degrees of freedom are considered. Eric Marchand is with Universit´e de Rennes 1, IRISA UMR 6074, INRIA Rennes-Bretagne Atlantique, Lagadic research group, email: Eric.Marchand@irisa.fr, Christophe Collewet

Paris-Sud XI, Université de

411

Modeling proton intensity gradients and radiation dose equivalents in the inner  

E-Print Network [OSTI]

Modeling proton intensity gradients and radiation dose equivalents in the inner heliosphere using a significant radiation hazard for manned and unmanned interplanetary (IP) space missions. In order to estimate intensities, event fluences, and radiation dose equivalents of 27­31 May 2003 SEP events at eight different

Pringle, James "Jamie"

412

Contributed Article On the momentum term in gradient descent learning algorithms  

E-Print Network [OSTI]

is that the steepest descent is particularly slow when there is a long and narrow valley in the error function surface. In this situation, the direction of the gradient is almost perpendicular to the long axis of the valley. The system the long axis of the valley. The momentum term helps average out the oscillation along the short axis while

Qian, Ning

413

To appear in Neural Networks On the Momentum Term in Gradient Descent Learning  

E-Print Network [OSTI]

is that the steepest descent is particularly slow when there is a long and narrow valley in the error function surface. In this situation, the direction of the gradient is almost perpendicular to the long axis of the valley. The system the long axis of the valley. The momentum term helps average out the oscillation along the short axis while

Qian, Ning

414

Seasonal mass-balance gradients in Norway L.A. RASMUSSEN,1  

E-Print Network [OSTI]

Seasonal mass-balance gradients in Norway L.A. RASMUSSEN,1 L.M. ANDREASSEN2,3 1 Department of Earth@ess.washington.edu 2 Norwegian Water Resources and Energy Directorate (NVE), PO Box 5091, Majorstua, NO-0301 Oslo, Norway 3 Department of Geosciences, University of Oslo, Blindern, NO-0316 Oslo, Norway ABSTRACT

Rasmussen, L.A.

415

MPC for Wind Power Gradients --Utilizing Forecasts, Rotor Inertia, and Central Energy Storage  

E-Print Network [OSTI]

MPC for Wind Power Gradients -- Utilizing Forecasts, Rotor Inertia, and Central Energy Storage iterations. We demonstrate our method in simulations with various wind scenarios and prices for energy. INTRODUCTION Today, wind power is the most important renewable energy source. For the years to come, many

416

Improving DWF Simulations: the Force Gradient Integrator and the Mbius Accelerated DWF Solver  

E-Print Network [OSTI]

We have implemented a variant of the force gradient integrator proposed by Kennedy et.al. and are using it in our production 2+1 flavor DWF simulations with pion masses of 180 MeV in (4.5fm)3 volumes. We find modest speed-ups (\\sim 20%) from using the force gradient integrator, compared to our previously used Omelyan integrator. On other ensembles, primarily finite temperature 2+1 flavor DWF QCD, we have extensively tuned the Hasenbusch preconditioning masses and achieved speed-ups of 2-3x. Here we have also switched to the force gradient integrator, but this change has not had any impact on the speed. We also report on an improved solver for DWF, which uses M\\"obius fermions, with a smaller fifth dimension than the original DWF fermions, as an intermediate step in the generation of solutions of the Dirac equation. This approach cuts the number of effective Dirac applications by approximately a factor of 2 when the conjugate gradient iteration count is large.

Hantao Yin; Robert D. Mawhinney

2011-11-21T23:59:59.000Z

417

Direct evidence for local oscillatory current sources and intracortical phase gradients in turtle  

E-Print Network [OSTI]

Direct evidence for local oscillatory current sources and intracortical phase gradients in turtle of several species. In turtle, these oscillations take the form of linear and circular traveling waves the origin of wave propagation in turtle visual cortex, we performed simultaneous measurements of the local

Kleinfeld, David

418

Water transport inside a single-walled carbon nanotube driven by temperature gradient  

E-Print Network [OSTI]

Water transport inside a single-walled carbon nanotube driven by temperature gradient J. Shiomi mass transport of a water cluster inside a single-walled carbon nanotube (SWNT) with the diameter of about 1.4 nm. The influence of the non-equilibrium thermal environment on the confined water cluster has

Maruyama, Shigeo

419

Full-potential calculations using the generalized gradient approximation: Structural properties of transition metals  

Science Journals Connector (OSTI)

The equilibrium volumes and bulk moduli of nonmagnetic 3d, 4d, and 5d transition metals have been calculated using a full-potential linear-muffin-tin-orbitals (FP-LMTO) method and the generalized gradient approximation (PW91) of Perdew and Wang [in Electronic Structure of Solids 1991, edited by P. Ziesche and H. Eschrig (Akademie Verlag, Berlin, 1991), Vol. 11]. The gradient-corrected FP-LMTO results are found to be superior to the corresponding local-density approximation (LDA) results in all transition-metal series. Furthermore, the atomic-spheres approximation (ASA) is found to yield larger equilibrium volumes and smaller bulk moduli than the FP method. The inaccuracies introduced by the ASA are of the same magnitude as the gradient corrections, suggesting that a FP treatment is important for gradient-corrected calculations. Excellent agreement with experiment is found for the c/a ratios of the hcp metals using both the LDA and the PW91, while for the fcc-bcc structural energy differences of 4d metals disagreement with semiempirical estimates remains.

V. Ozoli? and M. Krling

1993-12-15T23:59:59.000Z

420

Metabolic Consequences of a Reversed pH Gradient in Rat Tumors  

Science Journals Connector (OSTI)

...gradients of the ions, and the energy of ATP hydrolysis interact...total P1 along with AlP give us information about the energy status of the tissue, and measurements...lactate and pyruvate allow us, through equilibrium considerations...

Marion Stubbs; Loreta Rodrigues; Franklyn A. Howe; Jian Wang; Kyu-Shik Jeong; Richard L. Veech; and John R. Griffiths

Note: This page contains sample records for the topic "high gradient wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Condensation on Surface Energy Gradient Shifts Drop Size Distribution toward Small Drops  

E-Print Network [OSTI]

Condensation on Surface Energy Gradient Shifts Drop Size Distribution toward Small Drops Ashley M condensation from vapor onto a cooled surface, distributions of drops evolve by nucleation, growth is condensed onto a horizontally oriented surface that has been treated by silanization to deliver either

Daniel, Susan

422

RIS-M-2260 HEAT GRADIENT INDUCED MIGRATION OF BRINE INCLUSIONS IN ROCK SALT  

E-Print Network [OSTI]

;#12;- 5 - 1. INTRODUCTION The storage of heat producing radioactive waste in rock salt, will produce of the brine migration under influence of the decreasing heat production in the waste. A general expressionRIS?-M-2260 HEAT GRADIENT INDUCED MIGRATION OF BRINE INCLUSIONS IN ROCK SALT Mathematical treatment

423

Can selection on nest size from nest predation explain the latitudinal gradient in clutch size?  

E-Print Network [OSTI]

Can selection on nest size from nest predation explain the latitudinal gradient in clutch size. 2. The nest size hypothesis posits that higher nest predation in the tropics favours selection for smaller nests and thereby constrains clutch size by shrinking available space for eggs and/or nestlings

Martin, Thomas E.

424

Long wavelength gradient drift instability in Hall plasma devices. II. Applications  

SciTech Connect (OSTI)

Hall plasma devices with electron E B drift are subject to a class of long wavelength instabilities driven by the electron current, gradients of plasma density, temperature, and magnetic field. In the first companion paper [Frias et al., Phys. Plasmas 19, 072112 (2012)], the theory of these modes was revisited. In this paper, we apply analytical theory to show that modern Hall thrusters exhibit azimuthal and axial oscillations in the frequency spectrum from tens KHz to few MHz, often observed in experiments. The azimuthal phase velocity of these modes is typically one order of magnitude lower than the E B drift velocity. The growth rate of these modes scales inversely with the square root of the ion mass, ?1/?(m){sub i}. It is shown that several different thruster configurations share the same common feature: the gradient drift instabilities are localized in two separate regions, near the anode and in the plume region, and absent in the acceleration region. Our analytical results show complex interaction of plasma and magnetic field gradients and the E B drift flow as the sources of the instability. The special role of plasma density gradient is revealed and it is shown that the previous theory is not applicable in the region where the ion flux density is not uniform. This is particularly important for near anode region due to ionization and in the plume region due to diverging ion flux.

Frias, Winston; Smolyakov, Andrei I. [Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon SK S7N 5E2 (Canada)] [Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon SK S7N 5E2 (Canada); Kaganovich, Igor D.; Raitses, Yevgeny [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)] [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

2013-05-15T23:59:59.000Z

425

Beta-diversity on deep-sea wood falls reflects gradients in energy availability  

Science Journals Connector (OSTI)

...deep-sea wood falls reflects gradients in energy availability Craig McClain 1 James Barry...floor represent a significant source of energy into the food-limited deep sea. Unique...equated with considerable differences in energy usage and availability. Our findings...

2014-01-01T23:59:59.000Z

426

Temperature gradients, and search for non-Boussinesq effects, in the interior of turbulent Rayleigh-Bnard convection  

E-Print Network [OSTI]

Temperature gradients, and search for non-Boussinesq effects, in the interior of turbulent Rayleigh.1209/0295-5075/80/14001 Temperature gradients, and search for non-Boussinesq effects, in the interior of turbulent Rayleigh symmetry-breaking deviations from the Oberbeck-Boussinesq approximation even under conditions where

Haller, Gary L.

427

Video Operations in the Gradient Domain Fusion of image sequences is a fundamental operation in numerous video applications and usually  

E-Print Network [OSTI]

1 Video Operations in the Gradient Domain Abstract Fusion of image sequences is a fundamental operation in numerous video applications and usually consists of segmentation, matting and compositing. We present a unified framework for performing these operations on video in the gradient domain. Our approach

Cohen-Or, Daniel

428

Apparatus for the investigation of liquid systems in a shear gradient by small angle neutron scattering (SANS)  

E-Print Network [OSTI]

of small angle neutron scattering from fluids in a constant shear gradient. Typical systems which can angle neutron scattering experiments with liquids have given information about structural pro- perties759 Apparatus for the investigation of liquid systems in a shear gradient by small angle neutron

Boyer, Edmond

429

Microfluidic system with integrated electroosmotic pumps, concentration gradient generator and fish cell line (RTgill-W1)--towards water toxicity  

E-Print Network [OSTI]

Microfluidic system with integrated electroosmotic pumps, concentration gradient generator and fish that incorporates electroosmotic pumps, a concentration gradient generator and a fish cell line (rainbow trout gill concentration distribution of toxicant in a cell test chamber, (2) an electroosmotic (EO) pump chip

Le Roy, Robert J.

430

E-Print Network 3.0 - accelerator system accelerator Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

and Fusion Center, High-Energy-Density Physics Group Collection: Plasma Physics and Fusion ; Physics 80 Visual Exploration of Turbulent Combustion and Laser-Wakefield...

431

ATFNewsletter  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

P. Schoessow, A. Kanareykin, V. Yakimenko, A. Zholents & W. Gai High power terahertz radiation source based on electron beam wakefields, Rev. Sci. Instrum. 84, 022706 R....

432

Electron Acceleration Experiments by Using a Density-tapered Capillary Plasma Source  

Science Journals Connector (OSTI)

We have developed a density-tapered capillary plasma source for high energy electron generation by using the laser wakefield acceleration, where the dephasing problem will be...

Suk, Hyyong; Nam, Inhyuk; Kim, Minseok; Lee, Seungwoo; Lee, Taehee

433

Thermal Gradient Holes At Hawthorne Area (Sabin, Et Al., 2010) | Open  

Open Energy Info (EERE)

Sabin, Et Al., 2010) Sabin, Et Al., 2010) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Hawthorne Area (Sabin, Et Al., 2010) Exploration Activity Details Location Hawthorne Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness not indicated DOE-funding Unknown Notes In lieu of Seabee TGH drilling, GPO awarded a large IDIQ TGH drilling contract in December, 2009. Over the next two years, 90 500-ft TGHs will be installed at select sites in California and Nevada. Interim data from this campaign are already available for the Chocolate Mountains and Hawthorne. Results of these programs can be found in the Chocolate Mountains and Hawthorne papers also available in this volume. References Andrew Sabin, S. Bjornstad, M. Lazaro, D. Meade, C. Page, S. Alm, A.

434

Thermal Gradient Holes At Walker-Lane Transitional Zone Region (Pritchett,  

Open Energy Info (EERE)

Walker-Lane Transitional Zone Region (Pritchett, Walker-Lane Transitional Zone Region (Pritchett, 2004) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Walker-Lane Transitional Zone Region (Pritchett, 2004) Exploration Activity Details Location Walker-Lane Transition Zone Geothermal Region Exploration Technique Thermal Gradient Holes Activity Date Usefulness not useful DOE-funding Unknown Notes NOTE: These are theoretical/computer simulation tests of various methods on eight hypothetical 'model' basing-and-range geothermal systems. "The 300-meter heat flow holes are essentially useless for finding the "hidden" reservoirs. Clearly, the best results are obtained from the SP and MT surveys, with DC resistivity a close third. It is concluded that the best

435

Thermal Gradient Holes At Cove Fort Area (Warpinski, Et Al., 2002) | Open  

Open Energy Info (EERE)

Et Al., 2002) Et Al., 2002) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Cove Fort Area (Warpinski, Et Al., 2002) Exploration Activity Details Location Cove Fort Geothermal Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness not indicated DOE-funding Unknown Notes The project at Cove Fort/Sulphurdale in Utah, T26S R6/7W, is concerned with locating and drilling a 900-meter well to explore the western extension of the Cove Fort-Sulphurdale geothermal area. The geophysical exploration consisted of resistivity, ground magnetic, and microgravity surveys that were made to site the well in an optimum location. Drilling of the test well was completed in the fall of 2001 and results are currently being evaluated. The total depth of the well is 598 m with a

436

Thermal Gradient Holes At Spencer Hot Springs Area (Shevenell, Et Al.,  

Open Energy Info (EERE)

Hot Springs Area (Shevenell, Et Al., Hot Springs Area (Shevenell, Et Al., 2008) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Spencer Hot Springs Area (Shevenell, Et Al., 2008) Exploration Activity Details Location Spencer Hot Springs Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness useful DOE-funding Unknown Notes Collaboration with the gold mining industry has brought two new geothermal discoveries to the attention of the geothermal community. Exploration holes at Tungsten Mountain and McGuiness Hills (Spencer Hot Springs?) in 2004 and 2005 encountered hot water and steam at depths of meters with fluid geothermometry indicating reservoir temperatures of 170 to 200oC. More information can be obtained from the Nevada Bureau of Mines and Geology web

437

Thermal Gradient Holes At Fort Bidwell Area (Lafleur, Et Al., 2010) | Open  

Open Energy Info (EERE)

Bidwell Area (Lafleur, Et Al., 2010) Bidwell Area (Lafleur, Et Al., 2010) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Thermal Gradient Holes At Fort Bidwell Area (Lafleur, Et Al., 2010) Exploration Activity Details Location Fort Bidwell Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness useful DOE-funding Unknown Notes "Four wells have been successfully drilled into this resource since the early 1980s using a combination of funds provided by the California Energy Commission (CEC) and the United State Department of Energy (USDOE). The first three wells, FB-1, -2 and -3 have been discussed in a previous paper (Barker et al., 2005). The current status of the FBIC project to evaluate the potential geothermal resource under the reservation is that a deep

438

Automatic code generation enables nuclear gradient computations for fully internally contracted multireference theory  

E-Print Network [OSTI]

Analytical nuclear gradients for fully internally contracted complete active space second-order perturbation theory (CASPT2) are reported. This implementation has been realized by an automated code generator that can handle spin-free formulas for the CASPT2 energy and its derivatives with respect to variations of molecular orbitals and reference coefficients. The underlying complete active space self-consistent field and the so-called Z-vector equations are solved using density fitting. With full internal contraction the size of first-order wave functions scales polynomially with the number of active orbitals. The CASPT2 gradient program and the code generator are both publicly available. This work enables the CASPT2 geometry optimization of molecules as complex as those investigated by respective single-point calculations.

MacLeod, Matthew K

2015-01-01T23:59:59.000Z

439

Precisely mapping the magnetic field gradient in vacuum with an atom interferometer  

SciTech Connect (OSTI)

The magnetic field gradient has been measured with an atom interferometer using the magnetic sublevels of {sup 87}Rb atoms. The Doppler-insensitive measurement effectively eliminates the contribution from gravity and background vibration noise, and the differential measurement also can reject some systematic errors. A resolution of 300 pT/mm has been demonstrated with a 90-s integration time and a spatial resolution of 1.4 mm. The gradiometer was then used to measure the magnetic field gradient in an ultrahigh-vacuum environment. The technique will also be very useful to subtract the systematic error arising from the magnetic field inhomogeneity in precision atom-interferometry experiments, such as gravity measurement.

Zhou Minkang; Hu Zhongkun; Duan Xiaochun; Sun Buliang; Zhao Jinbo; Luo Jun [School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China)

2010-12-15T23:59:59.000Z

440

The effect of density gradient on the growth rate of relativistic Weibel instability  

SciTech Connect (OSTI)

In this paper, the effect of density gradient on the Weibel instability growth rate is investigated. The density perturbations in the near corona fuel, where temperature anisotropy, ?, is larger than the critical temperature anisotropy, ?{sub c}, (??>??{sub c}), enhances the growth rate of Weibel instability due to the sidebands coupled with the electron oscillatory velocity. But for ???2. The analysis shows that relativistic effects and density gradient tend to stabilize the Weibel instability. The growth rate can be reduced by 88% by reducing ? by a factor of 100 and increasing relativistic parameter by a factor of 3.

Mahdavi, M., E-mail: m.mahdavi@umz.ac.ir [Physics Department, University of Mazandaran, P.O. Box 47415-416, Babolsar (Iran, Islamic Republic of); Khodadadi Azadboni, F., E-mail: f.khodadadi@stu.umz.ac.ir [Physics Department, University of Mazandaran, P.O. Box 47415-416, Babolsar (Iran, Islamic Republic of); Young Researchers Club, Sari Branch, Islamic Azad University, P.O. Box 48161-194, Sari (Iran, Islamic Republic of)

2014-02-15T23:59:59.000Z

Note: This page contains sample records for the topic "high gradient wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Diversity and abundance of Pelagibacterales (SAR11) in the Baltic Sea salinity gradient  

Science Journals Connector (OSTI)

Abstract The candidate order Pelagibacterales (SAR11) is one of the most abundant bacterial orders in ocean surface waters and, periodically, in freshwater lakes. The presence of several stable phylogenetic lineages comprising Pelagibacterales correlates with the physico-chemical parameters in aquatic environments. A previous amplicon sequencing study covering the bacterial community in the salinity gradient of the Baltic Sea suggested that pelagibacteral subclade SAR11-I was replaced by SAR11-IIIa in the mesohaline region of the Baltic Sea. In this current study, we investigated the cellular abundances of Pelagibacterales subclades along the Baltic Sea salinity gradient using catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH). The results obtained with a newly designed probe, which exclusively detected SAR11-IIIa, were compared to CARD-FISH abundances of the marine SAR11-I/II subclade and the freshwater lineage SAR11-IIIb (LD12). The results showed that SAR11-IIIa was abundant in oligohalinemesohaline conditions (salinities 2.713.3), with maximal abundances at a salinity of 7 (up to 35% of total Bacteria, quantified with a universal bacterial probe EUB). As expected, SAR11-I/II was abundant (27% of EUB) in the marine parts of the Baltic Sea, whereas counts of the freshwater lineage SAR11-IIIb were below the detection limit at all stations. The shift from SAR11-IIIa to SAR11-I/II was confirmed in the vertical salinity gradient in the deeper basins of the Baltic Sea. These findings were consistent with an overlapping but defined distribution of SAR11-I/II and SAR11-IIIa in the salinity gradient of the Baltic Sea and suggested the adaptation of SAR11-IIIa for growth and survival in mesohaline conditions.

Daniel P.R. Herlemann; Jana Woelk; Matthias Labrenz; Klaus Jrgens

2014-01-01T23:59:59.000Z

442

Production of radioactivity in local soil at AGS (Alternating Gradient Synchrotron) fast neutrino beam  

SciTech Connect (OSTI)

Brookhaven National Laboratory (BNL) has constructed a new neutrino production target station at the Alternating Gradient Synchrotron (AGS). A study has been conducted in the vicinity of the old target area to determine the radiological consequences of operating this experimental facility. Results from all areas of the study are presented along with estimates of the potential environmental impact of the old and new facilities. 12 refs., 15 figs., 3 tabs.

Gollon, P.J.; Rohrig, N.; Hauptmann, M.G.; McIntyre, K.; Miltenberger, R.; Naidu, J.

1989-10-01T23:59:59.000Z

443

Simulations of magnetic field gradients due to micro-magnets on a triple quantum dot circuit  

SciTech Connect (OSTI)

To quantify the effects of local magnetic fields on triple quantum dots, the Heisenberg Hamiltonian has been diagonalized for three electrons coupled via the exchange interaction. In particular, we have investigated different geometries of micro-magnets located on top of the triple dot in order to optimize the field gradient characteristics. In this paper, we focus on two geometries which are candidates for an addressable EDSR triple quantum dot device.

Poulin-Lamarre, G. [National Research Council of Canada, Ottawa, On., Canada, K1A-0R6 and Dpartement de physique, Universit de Sherbrooke, Sherbrooke, Qc. J1K-2R1 (Canada); Bureau-Oxton, C. [Dpartement de physique, Universit de Sherbrooke, Sherbrooke, Qc. J1K-2R1 (Canada); Kam, A. [National Research Council of Canada, Ottawa, On. K1A-0R6 (Canada); Zawadzki, P.; Aers, G. [National Research Council of Canada, Ottawa, On. K1A-0R6 (Canada); Studenikin, S. [National Research Council of Canada, Ottawa, On.K1A-0R6 (Canada); Pioro-Ladrire, M. [Dpartement de physique, Universit de Sherbrooke, Sherbrooke, Qc. J1K-2R1 (Canada); Sachrajda, A. S. [National Research Council of Canada, Ottawa, On., Canada, K1A-0R6 and Dpartement de physique, Universit de Sherbrooke, Sherbrooke, Qc. J1K-2R1 (Canada)

2013-12-04T23:59:59.000Z

444

Nonperturbative broadening of paramagnetic resonance lines by transverse magnetic field gradients  

Science Journals Connector (OSTI)

We experimentally and theoretically study the broadening of paramagnetic resonance lines by transverse magnetic field gradients when a perturbative description is inadequate. The experiments are performed with an evanescent wave magnetometer using an octadecyltrichlorosilane-coated glass cell containing R87b and N2 buffer gas. We find that the transverse broadening of the resonance line is inversely proportional to the square root of the holding field. We also provide a quantitative theoretical explanation of the experimental results.

K. F. Zhao; M. Schaden; Z. Wu

2008-07-30T23:59:59.000Z

445

Gyrokinetic and Gyrofluid Models for Zonal Flow Dynamics in Ion and Electron Temperature Gradient Turbulence  

SciTech Connect (OSTI)

Collisionless time evolution of zonal flows in ion and electron temperature gradient turbulence in toroidal plasmas is investigated. The responses of the zonal-flow potential to the initial perturbation and to the turbulence source are determined from the gyrokinetic equations combined with the Poisson equation, A novel gyrofluid model is presented, which properly describes the zonal-flow time evolution and reproduces the same residual zonal-flow levels as predicted by the gyrokinetic model.

Sugama, H.; Watanabe, T.-H. [National Institute for Fusion Science, Toki, Gifu, 509-5292 (Japan); Graduate University for Advanced Studies, Toki, Gifu, 509-5292 (Japan); Ferrando i Margalet, S. [National Institute for Fusion Science, Toki, Gifu, 509-5292 (Japan)

2006-11-30T23:59:59.000Z

446

Coronal Heating Driven by Magnetic-gradient Pumping Mechanism in Solar Plasmas  

E-Print Network [OSTI]

The solar coronal heating is a longstanding mystery in astrophysics. Considering that the solar magnetic field is spatially inhomogeneous with considerable magnetic gradient from solar surface to the corona, this work proposes a magnetic gradient pumping (MGP) mechanism and try to explain the formation of hot plasma upflows, such as the hot type II spicules and hot plasma ejections, etc. In MGP mechanism, the magnetic gradients drive the energetic particles to move upwards from the underlying solar atmosphere and form hot upflows. These upflow energetic particles deposit in corona and make it becoming very hot. Roughly estimations indicate that the solar corona can be heated to above 1 million degrees, and the upflow velocity is about 40 km/s in chromosphere and about 130 km/s in the corona. The solar magnetic flux tubes act as pumpers to extract energetic particles from the underlying thermal photosphere, convey them and deposit in the corona. The deposition of energetic particles will make the corona become...

Tan, Baolin

2014-01-01T23:59:59.000Z

447

Curl-Free Pressure Gradients over Orography in a Solution of the Fully Compressible Euler Equations with Implicit Treatment of Acoustic and Gravity Waves  

Science Journals Connector (OSTI)

Steep orography can cause noisy solutions and instability in models of the atmosphere. A new technique for modeling flow over orography is introduced that guarantees curl-free gradients on arbitrary grids, implying that the pressure gradient term ...

Hilary Weller; Ava Shahrokhi

2014-12-01T23:59:59.000Z

448

In situ experimental study of reed leaf decomposition along a full salinity gradient  

Science Journals Connector (OSTI)

An experimental study on Phragmites australis leaf litter decomposition was conducted in the estuarine environment, Ria de Aveiro, Western Portugal, using the leaf-bag technique, with fine- (1mm) and coarse-mesh (5mm) bags. The leaf bags were placed in the field sites at day 0, covering a complete salinity gradient, and replicates were collected over time, at days 3 (leaching), 7, 15, 30 and 60. The biomass loss through the leaching phase, about 20% of the initial leaf mass, was independent of both the salinity and the bag mesh size. The biomass decay pattern along the salinity gradient varied through time and presented strong similarities between the two mesh sizes, with the remaining biomass always lower in the 5mm mesh-size bags. At days 7 and 15, the lowest remaining biomass was observed at the head of the estuary, the preferential distribution area of P. australis. At day 30, the remaining biomass was higher in the marine area and diminished under a direct relationship with salinity, reaching the lowest value in the freshwater environment, with values ranging from 66% to 44% of the initial weight in 5mm bags, and from 79% to 51% in 1mm bags. The largest heterogeneity in the remaining biomass among the study areas positioned along the salinity gradient was found close to days 30 (5mm) and 40 (1mm). The overall results indicate that the relationship between leaf decay rate and salinity depends on the decay time considered (k15, k30 or k60) and, for the later stages (k60), also on the leaf-bag mesh size. This implies that the use of leaf litter decay rates as a functional indicator in transitional waters will need to take into consideration the factor location in the salinity gradient and leaf litter stage at which the decay rate is determined. The differences between the decay rates with the mesh size acted mainly at the level of the absolute k value and not at the level of the pattern along the salinity gradient. Even so, the data obtained at the mouth of the estuary, in the area closest to a fully marine environment, indicated that after the initial biomass loss through leaching, P.australis decayed either very slowly, in the 5mm, or not at all, in the 1mm mesh bags.

Victor Quintino; Franca Sangiorgio; Fernando Ricardo; Renato Mamede; Adlia Pires; Rosa Freitas; Ana Maria Rodrigues; Alberto Basset

2009-01-01T23:59:59.000Z

449

Secondary Succession Dynamics in Estuarine Marshes across Landscape-Scale Salinity Gradients Author(s): Caitlin Mullan Crain, Lindsey K. Albertson, Mark D. Bertness  

E-Print Network [OSTI]

Secondary Succession Dynamics in Estuarine Marshes across Landscape-Scale Salinity Gradients AuthorAmerica SECONDARY SUCCESSION DYNAMICS IN ESTUARINE MARSHES ACROSS LANDSCAPE-SCALE SALINITY GRADIENTS Caitlin Mullan differences in the dynamics and assembly of marsh plant communities along estuarine salinity gradients

Bertness, Mark D.

450

CASTAt'ffiA 62(2): 112-118. J1JNE 1997 Plant Diversity Along a Salinity Gradient of Four  

E-Print Network [OSTI]

CASTAt'ffiA 62(2): 112-118. J1JNE 1997 Plant Diversity Along a Salinity Gradient of Four Marshes east coast along salinity gradients. They noted a large increase in species diversity of tidal and freshwater salinity gradient on the Mattaponi River, Virginia. However, these studies did not measure

Newman, Michael C.

451

Population dynamics and antimicrobial susceptibility of Aeromonas spp. along a salinity gradient in an urban estuary in Northeastern Brazil  

Science Journals Connector (OSTI)

Abstract The main objective of this study was to quantify population and identify culturable species of Aeromonas in sediment and surface water collected along a salinity gradient in an urban estuary in Northeastern Brazil. Thirty sediment samples and 30 water samples were collected from 3 sampling locations (A, B and C) between October 2007 and April 2008. The Aeromonas count was 107050CFU/mL (A), 2538,500CFU/mL (B) and<10CFU/mL (C) for water samples, and ?10037,500CFU/g (A), 120043,500CFU/g (B) and<10CFU/g (C) for sediment samples. Five species (Aeromonas caviae, A. sobria, A. trota, A. salmonicida and A. allosaccharophila) were identified among 41 isolates. All strains were sensitive to chloramphenicol and ceftriaxone, whereas 33 (80, 4%) strains were resistant to at least 2 of the 9 antibiotics tested. Resistance to erythromycin was mostly plasmidial. In conclusion, due to pollution, the Coc River is contaminated by pathogenic strains of Aeromonas spp. with a high incidence of antibacterial resistance, posing a serious risk to human health.

Camila Magalhes Silva; Norma Suely Evangelista-Barreto; Regine Helena Silva dos Fernandes Vieira; Kamila Vieira Mendona; Oscarina Viana de Sousa

2014-01-01T23:59:59.000Z

452

The Oberbeck-Boussinesq Equations. The Stability of Constant Gradient Solutions of the Oberbeck-Boussinesq Equations  

Science Journals Connector (OSTI)

The presence of density gradients in a fluid means that gravitational potential energy can be converted into motion through the action of buoyant forces. Density differences can be induced by heating the fluid an...

Daniel D. Joseph

1976-01-01T23:59:59.000Z

453

Design, prototyping, and testing of an apparatus for establishing a linear temperature gradient in experimental fish tanks  

E-Print Network [OSTI]

Immunology researchers require a new type of fish tank that provides a linear thermal gradient for experimental zebrafish in order to improve the accuracy and validity of their research. Zebrafish require the ability to ...

Kadri, Romi Sinclair

2014-01-01T23:59:59.000Z

454

Influences of Sea Surface Temperature Gradients and Surface Roughness Changes on the Motion of Surface Oil: A Simple Idealized Study  

Science Journals Connector (OSTI)

The authors' modeling shows that changes in sea surface temperature (SST) gradients and surface roughness between oil-free water and oil slicks influence the motion of the slick. Physically significant changes occur in surface wind speed, surface ...

Yangxing Zheng; Mark A. Bourassa; Paul Hughes

2013-07-01T23:59:59.000Z

455

Large Scale Marine Protected Areas for Biodiversity Conservation Along a Linear Gradient: Cooperation, Strategic Behavior or Conservation Autarky?  

Science Journals Connector (OSTI)

In this paper we investigate effects of overlap in species between ecosystems along a linear gradient on the location of marine protected areas (MPAs) under full cooperation, ... and conservation autarky lead to ...

Maarten J. Punt; Hans-Peter Weikard

2012-10-01T23:59:59.000Z

456

Cathodic reduction of hexavalent chromium coupled with electricity generation achieved by reverse-electrodialysis processes using salinity gradients  

Science Journals Connector (OSTI)

Abstract A new approach for the simultaneous generation of electric energy and the treatment of waters contaminated by recalcitrant pollutants using salinity gradients was proposed. Reverse electrodialysis allows for the generation of electric energy from salinity gradients. Indeed, the utilization of different salt concentrations gives a potential difference between the electrodes which allows the generation of electric energy by using suitable electrolytes and an external circuit. The simultaneous generation of electric energy and the treatment of waters contaminated by Cr(VI) was successfully achieved for the first time by reverse electrodialysis processes using salinity gradients and proper redox processes. The effect on the process of many operative parameters, such as the extent of the salinity gradient, the number of membrane pairs in the stack, the initial concentration of Cr(VI), the concentration of the supporting electrolyte and the flow rates of the solutions fed in the stack, was also investigated.

O. Scialdone; A. DAngelo; E. De Lum; A. Galia

2014-01-01T23:59:59.000Z

457

Changes in Community Structure of Sediment Bacteria Along the Florida Coastal Everglades MarshMangroveSeagrass Salinity Gradient  

Science Journals Connector (OSTI)

Community structure of sediment bacteria in the Everglades freshwater marsh, fringing mangrove forest, and Florida Bay seagrass meadows were described based on polymerase chain reaction-denaturing gradient gel el...

Makoto Ikenaga; Rafael Guevara; Amanda L. Dean; Cristina Pisani

2010-02-01T23:59:59.000Z

458

Prokaryotic aminopeptidase activity along a continuous salinity gradient in a hypersaline coastal lagoon (the Coorong, South Australia)  

Science Journals Connector (OSTI)

The distribution and aminopeptidase activity of prokaryotes were investigated along a natural continuous salinity gradient in a hypersaline coastal lagoon, the Coorong ... by flow cytometry, were observed along t...

Thomas Pollet; Mathilde Schapira; Marie-Jeanne Buscot; Sophie C Leterme

2010-04-01T23:59:59.000Z

459

Chlorophyll a biomass and growth of sea-ice microalgae along a salinity gradient (southeastern Hudson Bay, Canadian Arctic)  

Science Journals Connector (OSTI)

The biomass of microalgae at the bottom of first-year sea ice, in southeastern Hudson Bay (Canadian Arctic), parallels an inshore-offshore salinity gradient caused by the under-ice plume of ... ice-algal biomass ...

Louis Legendre; Marie-Jose Martineau; Jean-Claude Therriault

1992-09-01T23:59:59.000Z

460

Composition-Tailored Synthesis of Gradient Transition Metal Precursor Particles for Lithium-Ion Battery Cathode Materials  

Science Journals Connector (OSTI)

Composition-Tailored Synthesis of Gradient Transition Metal Precursor Particles for Lithium-Ion Battery Cathode Materials ... Collected particles were lithiated, and one promising material was evaluated as the active cathode component in a lithium-ion battery. ...

Gary M. Koenig, Jr.; Ilias Belharouak; Haixai Deng; Yang-Kook Sun; Khalil Amine

2011-03-09T23:59:59.000Z

Note: This page contains sample records for the topic "high gradient wakefield" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Latitudinal gradients of coniferous tree species, vegetation, and climate in the Sierran-Cascade axis of Northern California  

Science Journals Connector (OSTI)

Latitudinal gradients of tree species composition along the Sierran/Cascade axis in northern California were explored by comparing forests of Lassen Volcanic and Yosemite National Parks, USA. A calibration pro...

Albert J. Parker

1994-12-01T23:59:59.000Z

462

Fertility of stallion spermatozoa separated on albumin gradients and attempts to control the sex ratio of foals  

E-Print Network [OSTI]

December 1985 Major Subject: Physiology of Reproduction FERTILITY OF STALLION SPERMATOZOA SEPARATED ON ALBUMIN GRADIENTS AND ATTEMPTS TO CONTROL THE SEX RATIO OF FOALS h Thesis by JANE ANN PRUITT Approved as to style and content by: (Chair... of Committe) (Member) J, M. Bowen (Member) G. C. Smith (Head of Department) December 1985 ABSTRACT Fertility of Stallion Spermatozoa Separated on Albumin Gradients and Attempts to Control the Sex Ratio of Foals (December 1985) Jane Ann Pruitt, B. S...

Pruitt, Jane Ann

1985-01-01T23:59:59.000Z

463

Influence of Natural Organic Matter Fouling and Osmotic Backwash on Pressure Retarded Osmosis Energy Production from Natural Salinity Gradients  

Science Journals Connector (OSTI)

Influence of Natural Organic Matter Fouling and Osmotic Backwash on Pressure Retarded Osmosis Energy Production from Natural Salinity Gradients ... Therefore, SRNOM fouling of porous support in PRO detrimentally constrains the ability of the membrane to convert salinity gradient energy into useful work. ... Other unique areas of forward osmosis research include pressure-retarded osmosis for generation of electricity from saline and fresh water and implantable osmotic pumps for controlled drug release. ...

Ngai Yin Yip; Menachem Elimelech

2013-09-19T23:59:59.000Z

464

Evaluation of Low-Salinity Enhanced Oil Recovery Effects in Sandstone: Effects of the Temperature and pH Gradient  

Science Journals Connector (OSTI)

Evaluation of Low-Salinity Enhanced Oil Recovery Effects in Sandstone: Effects of the Temperature and pH Gradient ... (1-4) It was very interesting to see that the model compound, quinoline, and an asphaltenic crude oil responded similarly regarding adsorption/desorption from clays at different salinities and pH values. ... (3) Can the slopes of the pH gradients give information about the rate of desorption and adsorption of cations? ...

Hakan Aksulu; Dagny Hms; Skule Strand; Tina Puntervold; Tor Austad

2012-04-24T23:59:59.000Z

465

A comparison of experimental and theoretical results for leakage, pressure gradient, and rotordynamic coefficients for tapered annular gas seals  

E-Print Network [OSTI]

A COMPARISON OF EXPERIMENTAL AND THEORETICAL RESULTS FOR LEAKAGE, PRESSURE GRADIENT, AND ROTORDYNAMIC COEFFICIENTS FOR TAPERED ANNULAR GAS SEALS A Thesis by DAVID ALAN ELROD Submitted to the Graduate College of Texas A&M University... ABSTRACT A Compar ison of Experimental and Theoretical Results for Leakage, Pressure Gradient, and Rotordynamic Coefficients for Tapered Annular Gas Seals. (December 1986) David Alan Elrod, 8 . S . , Louisiana State University Co-Chairs of Advisory...

Elrod, David Alan

1986-01-01T23:59:59.000Z

466

Formation of compressed flat electron beams with high transverse-emittance ratios  

SciTech Connect (OSTI)

Flat beamsbeams with asymmetric transverse emittanceshave important applications in novel light-source concepts and advanced-acceleration schemes and could possibly alleviate the need for damping rings in lepton colliders. Over the last decade, a flat beam generation technique based on the conversion of an angular-momentum-dominated beam was proposed and experimentally tested. In this paper we explore the production of compressed flat beams. We especially investigate and optimize the flat beam transformation for beams with substantial fractional energy spread. We use as a simulation example the photoinjector of Fermilabs Advanced Superconducting Test Accelerator. The optimizations of the flat beam generation and compression at Advanced Superconducting Test Accelerator were done via start-to-end numerical simulations for bunch charges of 3.2 nC, 1.0 nC, and 20 pC at ?37??MeV. The optimized emittances of flat beams with different bunch charges were found to be 0.25???m (emittance ratio is ?400), 0.13????m, 15 nm before compression, and 0.41???m, 0.20???m, 16 nm after full compression, respectively, with peak currents as high as 5.5 kA for a 3.2?nC flat beam. These parameters are consistent with requirements needed to excite wakefields in asymmetric dielectric-lined waveguides or produce significant photon flux using small-gap micro-undulators.

Zhu, J. [Fermilab; Institute of Fluid Physics, CAEP, China; Piot, P. [Northern Illinois University; Fermilab; Mihalcea, D. [Northern Illinois University; Prokop, C. R. [Northern Illinois University

2014-08-01T23:59:59.000Z

467

FLOW RESISTANCE ESTIMATION IN HIGH-GRADIENT STREAMS Steven Yochum, Hydrologist, USDA Natural Resources Conservation Service & Colorado  

E-Print Network [OSTI]

and waterfalls impact on standing water, resulting in substantial turbulence. In step-pool and cascade streams Resources Conservation Service & Colorado State University, Fort Collins, CO, steven for low, mid and near-bankfull flows in cascade, step pool and plane bed stream reaches in the Fraser

Bledsoe, Brian

468

High-pressure-temperature gradient instrument: use for determining the temperature and pressure limits of bacterial growth.  

Science Journals Connector (OSTI)

...shows the valve manifold (VM), the polystyrene foam insulation (U), and the therm- istor probe (TM) for determining...which the samples were loaded. U is the polystyrene foam insulation, AB is the aluminum block, TW the thermometer well...

A A Yayanos; R van Boxtel; A S Dietz

1984-10-01T23:59:59.000Z

469

Large-scale altitudinal gradient of natural rubber production in Vietnam  

Science Journals Connector (OSTI)

Investigation of elevation dependence of latex productivity of natural rubber (NR, Hevea brasiliensis Mull. Arg.) plantations and determination of elevation thresholds for landuse management are an urgent need of study. The current study was, therefore, conducted, aiming to investigate attitudinal gradient of NR production in Vietnam. The study was based on 146,000ha of harvested NR plantations located from the southeast region to highland. There were 45 NR clones planted in the areas studied and GT1, the clone planted with a largest portion, was examined separately from the other 44 clones, combined in processing (the Rest). Three main variables, latex productivity, individual yield and tapping density were calculated for two tapping periods, from year 1 to 10 (110) and from year 11 to 20 (1120). Over the investigated elevation range, 15738m, the latex productivity declined at different rates, 109 for GT1 (110), 127 for GT1 (1120), 110 for the Rest (110) and 117kgha?1year?1 for the Rest (1120) for every 100-m increase in elevation. An S-like curve, obtained by fitting latex productivity along the altitudinal gradient using 3-order polynomial could be separated into three stages, of which the first and the last stages were characterized with a rapid drop of, and the middle was with a stability of, latex productivity. With a rise in elevation, tapping density (tapped treeha?1) and individual yield (kgtree?1year?1) significantly declined. As tapping density increased, individual yield declined whereas latex productivity rose. The results indicated that not all lands are suitable for a good NR production and that only areas with elevation under a certain magnitude depending on individual NR clones should be considered for NR cultivation. The altitudinal gradient of NR production could involve a number of soil and climatic variables, which need to be further investigated.

Binh Thanh Nguyen

2013-01-01T23:59:59.000Z

470

Functionally gradient material for membrane reactors to convert methane gas into value-added products  

DOE Patents [OSTI]

A functionally gradient material for a membrane reactor for converting methane gas into value-added-products includes an outer tube of perovskite, which contacts air; an inner tube which contacts methane gas, of zirconium oxide, and a bonding layer between the perovskite and zirconium oxide layers. The bonding layer has one or more layers of a mixture of perovskite and zirconium oxide, with the layers transitioning from an excess of perovskite to an excess of zirconium oxide. The transition layers match thermal expansion coefficients and other physical properties between the two different materials. 7 figs.

Balachandran, U.; Dusek, J.T.; Kleefisch, M.S.; Kobylinski, T.P.

1996-11-12T23:59:59.000Z

471

The analytic gradient of the perturbative triplet excitations correction to the Brueckner doubles method  

Science Journals Connector (OSTI)

To determine correlated properties accurately, it is necessary to go beyond the level of single and double excitations from a single determinant and include the effects of the connected triple excitations. A formula for the analytic gradient of the closed-shell perturbative triple excitations correction is presented for the Brueckner doubles varinat of coupled cluster theory. Optimised geometries and harmonic frequencies are presented for H2O and the multiple bonded systems HCN, NNO and O3. For these molecules, the use of Brueckner orbitals and the triples contribution show significant effects.

Rika Kobayashi; Roger D. Amos; Nicholas C. Handy

1991-01-01T23:59:59.000Z

472

Functionally gradient material for membrane reactors to convert methane gas into value-added products  

DOE Patents [OSTI]

A functionally gradient material for a membrane reactor for converting methane gas into value-added-products includes an outer tube of perovskite, which contacts air; an inner tube which contacts methane gas, of zirconium oxide, and a bonding layer between the perovskite and zirconium oxide layers. The bonding layer has one or more layers of a mixture of perovskite and zirconium oxide, with the layers transitioning from an excess of perovskite to an excess of zirconium oxide. The transition layers match thermal expansion coefficients and other physical properties between the two different materials.

Balachandran, Uthamalingam (Hinsdale, IL); Dusek, Joseph T. (Lombard, IL); Kleefisch, Mark S. (Napersville, IL); Kobylinski, Thadeus P. (Lisle, IL)

1996-01-01T23:59:59.000Z

473

Density-functional theory of macroscopic stress: Gradient-corrected calculations for crystalline Se  

Science Journals Connector (OSTI)

We generalize the Nielsen-Martin stress theorem beyond the local-density approximation (LDA) and present an alternative derivation of the whole theorem. We show that the exchange-correlation stress becomes anisotropic in the most general case: its explicit form is given within a gradient-corrected (GC) scheme. As a test implementation, we use the generalized theorem to achieve fast structural optimization in crystalline Se. In this material LDA predicts a rather poor structure period. Our GC calculation is in much better agreement with the experiment.

Andrea Dal Corso and Raffaele Resta

1994-08-15T23:59:59.000Z

474

Self-organized profile relaxation by ion temperature gradient instability in toroidal plasmas  

SciTech Connect (OSTI)

Toroidal effects on the ion-temperature gradient mode are found to dictate the temperature evolution and the subsequent relaxed profile realization according to our toroidal particle simulation. Both in the strongly unstable fluid regime as well as in the near-marginal kinetic regime we observe that the plasma maintains an exponential temperature profile and forces the heat flux to be radially independent. The self-organized critical relaxed state is sustained slightly above the marginal stability, where the weak wave growth balances the wave decorrelation.

Kishimoto, Y.; Tajima, T.; LeBrun, M.J.; Gray, M.G.; Kim, J.Y.; Horton, W.

1993-02-01T23:59:59.000Z

475

Comparison of analytical models for zonal flow generation in ion-temperature-gradient mode turbulence  

SciTech Connect (OSTI)

During the past years the understanding of the multi scale interaction problems have increased significantly. However, at present there exists a flora of different analytical models for investigating multi scale interactions and hardly any specific comparisons have been performed among these models. In this work two different models for the generation of zonal flows from ion-temperature-gradient (ITG) background turbulence are discussed and compared. The methods used are the coherent mode coupling model and the wave kinetic equation model (WKE). It is shown that the two models give qualitatively the same results even though the assumption on the spectral difference is used in the (WKE) approach.

Anderson, J.; Miki, K.; Uzawa, K.; Li, J.; Kishimoto, Y. [Dept. Fundamental Energy Science, School of Energy Science, Kyoto University, Gokasho, Uji, Kyoto, 611-0011 (Japan)

2006-11-30T23:59:59.000Z

476

Gyrokinetic-Vlasov simulations of the ion temperature gradient turbulence in tokamak and helical systems  

SciTech Connect (OSTI)

Recent progress of the gyrokinetic-Vlasov simulations on the ion temperature gradient (ITG) turbulence in tokamak and helical systems is reported, where the entropy balance is checked as a reference for the numerical accuracy. The tokamak ITG turbulence simulation carried out on the Earth Simulator clearly captures a nonlinear generation process of zonal flows. The tera-flops and tera-bytes scale simulation is also applied to a helical system with the same poloidal and toroidal periodicities of L = 2 and M = 10 as in the Large Helical Device.

Watanabe, T.-H.; Sugama, H. [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Graduate University for Advanced Studies (Sokendai), Toki, Gifu 509-5292 (Japan); Ferrando i Margalet, S. [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan)

2006-11-30T23:59:59.000Z

477

Rotating-frame gradient fields for magnetic resonance imaging and nuclear magnetic resonance in low fields  

DOE Patents [OSTI]

A system and method for Fourier encoding a nuclear magnetic resonance (NMR) signal is disclosed. A static magnetic field B.sub.0 is provided along a first direction. An NMR signal from the sample is Fourier encoded by applying a rotating-frame gradient field B.sub.G superimposed on the B.sub.0, where the B.sub.G comprises a vector component rotating in a plane perpendicular to the first direction at an angular frequency .omega.in a laboratory frame. The Fourier-encoded NMR signal is detected.

Bouchard, Louis-Serge; Pines, Alexander; Demas, Vasiliki

2014-01-21T23:59:59.000Z

478

Adiabatic Formation of a Matched-beam Distribution for an Alternating-gradient Quadrupole Lattice  

SciTech Connect (OSTI)

The formation of a quasiequilibrium beam distribution matched to an alternating-gradient quadrupole focusing lattice by means of the adiabatic turn-on of the oscillating focusing field is studied numerically using particle-in-cell simulations. Quiescent beam propagation over several hundred lattice periods is demonstrated for a broad range of beam intensities and vacuum phase advances describing the strength of the oscillating focusing field. Properties of the matched-beam distribution are investigated. In particular, self-similar evolution of the beam density profile is observed over a wide range of system parameters. The numerical simulations are performed using the WARP particle-in-cell code.

Mikhail A. Dorf, Ronald C. Davidson, Edward A. Startsev, and Hong Qin

2010-02-02T23:59:59.000Z

479

Thermal Transients During Processing of 3003 Al-H18 Multilayer Build by Very High-Power Ultrasonic Additive Manufacturing  

Science Journals Connector (OSTI)

Previous investigations suggested a gradient in bond microstructure along the height of a build made by very high power ultrasonic additive manufacturinga rapid prototyping process that is based...

M. R. Sriraman; Matt Gonser; Daniel Foster

2012-02-01T23:59:59.000Z

480

Atom interferometric techniques for measuring gravitational acceleration and constant magnetic field gradients  

E-Print Network [OSTI]

We discuss two techniques for probing the effects of a homogeneous force acting on cold atoms, such as that due to gravity or a constant magnetic field gradient, using grating echo-type atom interferometers. A comprehensive theoretical description of signals generated by both two-pulse and three-pulse interferometers, accounting for magnetic sub-levels in the atomic ground state, is shown to agree with experimental results. Laser-cooled samples of $^{85}$Rb with temperatures as low as 2.4 $\\mu$K have been achieved in a relatively large glass cell with well-suppressed magnetic fields. Using transit time limited interferometer signals, we demonstrate sensitivity to externally applied magnetic gradients as small as $\\sim 4$ mG/cm. With these timescales we estimate that precision measurements of the gravitational acceleration, $g$, are possible with both the two-pulse and three-pulse echo interferometers. Whereas the two-pulse signal is a position-sensitive technique to measure the absolute value of $g$, the thre...

Barrett, B

2011-01-01T23:59:59.000Z

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481

Numerical simulation of supercritical heat transfer under severe axial density gradient in a narrow vertical tube  

SciTech Connect (OSTI)

A number of computational works have been performed so far for the simulation of heat transfer in a supercritical fluid. The simulations, however, faced a lot of difficulties when heat transfer deteriorates due either to buoyancy or by acceleration. When the bulk temperature approaches the pseudo-critical temperature the fluid experiences a severe axial density gradient on top of a severe radial one. Earlier numerical calculations showed, without exception, unrealistic over-predictions, as soon as the bulk temperature exceeded the pseudo-critical temperature. The over-predictions might have been resulted from an inapplicability of widely-used turbulence models. One of the major causes for the difficulties may probably be an assumption of a constant turbulent Prandtl number. Recent research, both numerical and experimental, indicates that the turbulent Prandtl number is never a constant when the gradient of physical properties is significant. This paper describes the applicability of a variable turbulent Prandtl number to the numerical simulation of heat transfer in supercritical fluids flowing in narrow vertical tubes. (authors)

Bae, Y. Y.; Hong, S. D.; Kim, Y. W. [Korea Atomic Energy Research Inst., 1045 Daedeokdaero, Daejeon (Korea, Republic of)

2012-07-01T23:59:59.000Z

482

Life in the salinity gradient: Discovering mechanisms behind a new biodiversity pattern  

Science Journals Connector (OSTI)

Abstract A recently discovered paradoxical maximum of planktonic protistan species in the salinity gradient of the Baltic Sea revealed an inverse trend of species number/salinity relation in comparison to the previously accepted species-minimum model for macrozoobenthos. Here, we review long-term data on organisms of different size classes and ecological groups to show that eukaryotic and prokaryotic microbes in plankton demonstrate a maximum species richness in the challenging zone of the critical salinity 58, where the large-bodied bottom dwellers (macrozoobenthos, macroalgae and aquatic higher plants) experience large-scale salinity stress which leads to an impoverished diversity. We propose a new conceptual model to explain why the diversity of small, fast-developing, rapidly evolving unicellular plankton organisms benefits from relative vacancy of brackish-water ecological niches and impaired competitiveness therein. The ecotone theory, Hutchinson's Ecological Niche Concept, speciesarea relationships and the Intermediate Disturbance Hypothesis are considered as a theoretical framework for understanding extinctions, speciation and variations in the evolution rates of different aquatic species in ecosystems with the pronounced salinity gradient.

Irena Telesh; Hendrik Schubert; Sergei Skarlato

2013-01-01T23:59:59.000Z

483

Nanocomposite reverse electrodialysis (RED) ion-exchange membranes for salinity gradient power generation  

Science Journals Connector (OSTI)

Abstract Despite the important role of ion-exchange membranes (IEMs) in reverse electrodialysis (RED) systems, the current absence of proper ion-exchange membranes delays the sustainable development of the RED process for salinity gradient power generation. This research presents the preparation of a new type of organicinorganic nanocomposite cation exchange membrane and its performance characteristics. The combination of functionalized iron (III) oxide ( Fe 2 O 3 - SO 4 2 ? ) as an inorganic filler with the sulfonated poly (2,6-dimethyl-1,4-phenylene oxide) (sPPO) polymer matrix proved to have great potential for power generation by RED. The results showed that an optimal amount of Fe 2 O 3 - SO 4 2 ? (0.50.7wt%) enhanced the key electrochemical properties of the ion-exchange membranes including a permselectivity up to 87.65% and an area resistance of 0.87?cm2. The nanocomposite membrane containing 0.7wt% ( Fe 2 O 3 - SO 4 2 ? ) achieved a maximum power density (amount of power per unit membrane area) of 1.3Wm?2, which is relatively higher than that of the commercially available CSO (SelemionTM, Japan) membranes. The goal of the present work is to maximize the salinity gradient power generation by developing RED-specific nanocomposite IEMs. The results show the potential of the new design of the nanocomposite \\{IEMs\\} for viable energy generation by RED.

Jin Gi Hong; Yongsheng Chen

2014-01-01T23:59:59.000Z

484

Performance of conjugate gradient-like algorithms in transient two-phase subchannel analysis  

SciTech Connect (OSTI)

A transient, drift-flux subchannel analysis code (SWIRL) has been created for the development and evaluation of algorithms for the solution of weakly three-dimensional fluid flow problems. Spatial discretization on a staggered grid, semi-implicit temporal discretization, and algebraic reduction of the conservation equations of mass, energy, and momentum result in nonsymmetric block-tridiagonal linear systems of equations that must be solved for the pressure distribution at each time step of a transient. The solution of these systems of equations is the most time-consuming portion of the code, and direct, stationary iterative, and preconditioned conjugate gradient (CG)-like methods have been investigated both for a simple approach to steady-state and for a severe transient. The best direct algorithm appears to be an efficient implementation of block elimination, and iterative methods are compared to this algorithm for accuracy, robustness, and efficiency. Results presented here indicate that preconditioned CG-like methods such as Sonneveld's conjugate gradients squared are superior to an efficient direct method. 44 refs., 13 figs.

Turner, J.A. (Los Alamos National Lab., NM (USA)); Doster, M.J. (North Carolina State Univ., Raleigh, NC (USA). Dept. of Nuclear Engineering)

1991-01-01T23:59:59.000Z

485

Fine-Scale Zonal Flow Suppression of Electron Temperature Gradient Turbulence  

SciTech Connect (OSTI)

It is found in collisionless Electron Temperature Gradient (ETG) turbulence simulations that, while zonal flows are weak at early times, the zonal flows continue to grow algebraically (proportional to time). These fine-scale zonal flows have a radial wave number such that kr{rho}i > 1 and kr{rho}e < 1. Eventually, the zonal flows grow to a level that suppresses the turbulence due to ExB shearing. The final electron energy flux is found to be relatively low. These conclusions are based on particle convergence studies with adiabatic ion electrostatic flux-tube gyrokinetic {delta}f particle simulations run for long times. The Rosenbluth-Hinton random walk mechanism is given as an explanation for the long time build up of the zonal flow in ETG turbulence and it is shown that the generation is (k perpendicular {rho}e)2 smaller than for isomorphic Ion Temperature Gradient (ITG) problem. This mechanism for zonal flow generation here is different than the modulational instability mechanism for ITG turbulence. These results are important because previous results indicated zonal flows were unimportant for ETG turbulence. Weak collisional damping of the zonal flow is also shown to be a n important effect.

Parker, S. E.; Kohut, J. J.; Chen, Y. [Center for Integrated Plasma Studies, University of Colorado, Boulder, C0 (United States); Lin, Z. [University of Californian, Irvine, CA (United States); Hinton, F. L. [Hinton Associates, Escondido, CA (United States); Lee, W. W. [Princeton Plasma Physics Laboratory, Princeton, NJ (United States)

2006-11-30T23:59:59.000Z

486

Ion-temperature-gradient sensitivity of the hydrodynamic instability caused by shear in the magnetic-field-aligned plasma flow  

SciTech Connect (OSTI)

The cross-magnetic-field (i.e., perpendicular) profile of ion temperature and the perpendicular profile of the magnetic-field-aligned (parallel) plasma flow are sometimes inhomogeneous for space and laboratory plasma. Instability caused either by a gradient in the ion-temperature profile or by shear in the parallel flow has been discussed extensively in the literature. In this paper, (1) hydrodynamic plasma stability is investigated, (2) real and imaginary frequency are quantified over a range of the shear parameter, the normalized wavenumber, and the ratio of density-gradient and ion-temperature-gradient scale lengths, and (3) the role of inverse Landau damping is illustrated for the case of combined ion-temperature gradient and parallel-flow shear. We find that increasing the ion-temperature gradient reduces the instability threshold for the hydrodynamic parallel-flow shear instability, also known as the parallel Kelvin-Helmholtz instability or the D'Angelo instability. We also find that a kinetic instability arises from the coupled, reinforcing action of both free-energy sources. For the case of comparable electron and ion temperature, we illustrate analytically the transition of the D'Angelo instability to the kinetic instability as (a) the shear parameter, (b) the normalized wavenumber, and (c) the ratio of density-gradient and ion-temperature-gradient scale lengths are varied and we attribute the changes in stability to changes in the amount of inverse ion Landau damping. We show that near a normalized wavenumber k{sub ?}?{sub i} of order unity (i) the real and imaginary values of frequency become comparable and (ii) the imaginary frequency, i.e., the growth rate, peaks.

Mikhailenko, V. V., E-mail: vladimir@pusan.ac.kr [Plasma Research Center, Pusan National University, Busan 609-735 (Korea, Republic of); Mikhailenko, V. S. [School of Physics and Technology, V.N. Karazin Kharkiv National University, 61108 Kharkiv (Ukraine); Faculty of Transportation Systems, Kharkiv National Automobile and Highway University, 61002 Kharkiv (Ukraine); Lee, Hae June, E-mail: haejune@pusan.ac.kr [Department of Electrical Engineering, Pusan National University, Busan 609-735 (Korea, Republic of); Koepke, M. E. [Department of Physics, West Virginia University, Morgantown, West Virginia 26506 (United States)

2014-07-15T23:59:59.000Z

487

High voltage RF feedthrough bushing  

DOE Patents [OSTI]

Described is a multi-element, high voltage radio frequency bushing for trmitting RF energy to an antenna located in a vacuum container. The bushing includes a center conductor of complex geometrical shape, an outer coaxial shield conductor, and a thin-walled hollow truncated cone insulator disposed between central and outer conductors. The shape of the center conductor, which includes a reverse curvature portion formed of a radially inwardly directed shoulder and a convex portion, controls the uniformity of the axial surface gradient on the insulator cone. The outer shield has a first substantially cylindrical portion and a second radially inwardly extending truncated cone portion.

Grotz, Glenn F. (Huntington Station, NY)

1984-01-01T23:59:59.000Z

488

The Role of Postintervention Pullback Pressure Gradient in Percutaneous Transluminal Angioplasty for Central Vein Stenosis in Dialysis Patients  

SciTech Connect (OSTI)

Purpose: The severity of residual stenosis (RS) sometimes cannot be accurately measured by angiography during central vein intervention. This study evaluated the role of pullback pressure measurement during central vein stenosis (CVS) intervention. Methods: A retrospective review enrolled 94 consecutive dialysis patients who underwent CVS interventions but not stenting procedures. Patients were classified into 2 groups by either angiography or pressure gradient (PG) criteria, respectively. Groups divided by angiographic result were successful group (RS {<=}30 %) and acceptable group (50 % {>=} RS > 30 %), while groups divided by PG were low PG group (PG {<=}5 mmHg) and high PG group (PG >5 mmHg). Baseline characteristics and 12-month patency rates between the groups were analyzed. Results: The angiography results placed 63 patients in the successful group and 31 patients in the acceptable group. The patency rate at 12 month was not statistically different (P = 0.167). When the patients were reclassified by the postintervention pullback PG, the patency rate at 12 months was significant (P = 0.048). Further analysis in groups redivided by different combinations of RS and PG criteria identified significant differences in the group with both RS {<=}30 % and PG {<=}5 mmHg compared with those with either RS >30 % (P = 0.047) or PG >5 mmHg (P = 0.027). In addition, there was a significant difference between those with both RS {<=}30 % and PG {<=}5 mmHg compared with those with both RS >30 % and PG >5 mmHg (P = 0.027). Conclusion: Postintervention PG can better predict long-term outcomes after angioplasty for CVS in nonstented dialysis patients than angiography.

Lin, Yu-Sheng, E-mail: dissertlin@yahoo.com.tw [Chang Gung Memorial Hospital, Chiayi, Chang Gung Institute of Technology, Division of Cardiology (China)] [Chang Gung Memorial Hospital, Chiayi, Chang Gung Institute of Technology, Division of Cardiology (China); Yang, Cheng-Hsu, E-mail: yangch@adm.cgmh.org.tw [Chang Gung Memorial Hospital-Kaohsiung Medical Center, Chang Gung University College of Medicine, Division of Cardiology and Department of Internal Medicine (China)] [Chang Gung Memorial Hospital-Kaohsiung Medical Center, Chang Gung University College of Medicine, Division of Cardiology and Department of Internal Medicine (China); Chu, Chi-Ming, E-mail: chuchiming@ndmctsgh.edu.tw [National Defense Medical Center and University, Section of Health Informatics, Institute of Public Health (China)] [National Defense Medical Center and University, Section of Health Informatics, Institute of Public Health (China); Fang, Chi-Yung, E-mail: cyfang@seed.net.tw; Chen, Chien-Jen, E-mail: cjchen@adm.cgmh.org.tw [Chang Gung Memorial Hospital-Kaohsiung Medical Center, Chang Gung University College of Medicine, Division of Cardiology and Department of Internal Medicine (China)] [Chang Gung Memorial Hospital-Kaohsiung Medical Center, Chang Gung University College of Medicine, Division of Cardiology and Department of Internal Medicine (China); Hsu, Jen-Te, E-mail: hsujente@gmail.com; Yang, Teng-Yao, E-mail: 2859@adm.cgmh.org.tw [Chang Gung Memorial Hospital, Chiayi, Chang Gung Institute of Technology, Division of Cardiology (China)] [Chang Gung Memorial Hospital, Chiayi, Chang Gung Institute of Technology, Division of Cardiology (China); Hang, Chi-Ling, E-mail: samuelhang@hotmail.com; Wu, Chiung-Jen, E-mail: cvcjwu@adm.cgmh.org.tw [Chang Gung Memorial Hospital-Kaohsiung Medical Center, Chang Gung University College of Medicine, Division of Cardiology and Department of Internal Medicine (China)] [Chang Gung Memorial Hospital-Kaohsiung Medical Center, Chang Gung University College of Medicine, Division of Cardiology and Department of Internal Medicine (China)

2013-10-15T23:59:59.000Z

489

Analytical energy gradient based on spin-free infinite-order Douglas-Kroll-Hess method with local unitary transformation  

SciTech Connect (OSTI)

In this study, the analytical energy gradient for the spin-free infinite-order Douglas-Kroll-Hess (IODKH) method at the levels of the Hartree-Fock (HF), density functional theory (DFT), and second-order Mller-Plesset perturbation theory (MP2) is developed. Furthermore, adopting the local unitary transformation (LUT) scheme for the IODKH method improves the efficiency in computation of the analytical energy gradient. Numerical assessments of the present gradient method are performed at the HF, DFT, and MP2 levels for the IODKH with and without the LUT scheme. The accuracies are examined for diatomic molecules such as hydrogen halides, halogen dimers, coinage metal (Cu, Ag, and Au) halides, and coinage metal dimers, and 20 metal complexes, including the fourthsixth row transition metals. In addition, the efficiencies are investigated for one-, two-, and three-dimensional silver clusters. The numerical results confirm the accuracy and efficiency of the present method.

Nakajima, Yuya; Seino, Junji [Department of Chemistry and Biochemistry, School of Advanced Science and Engineering, Waseda University, Tokyo 169-8555 (Japan)] [Department of Chemistry and Biochemistry, School of Advanced Science and Engineering, Waseda University, Tokyo 169-8555 (Japan); Nakai, Hiromi, E-mail: nakai@waseda.jp [Department of Chemistry and Biochemistry, School of Advanced Science and Engineering, Waseda University, Tokyo 169-8555 (Japan) [Department of Chemistry and Biochemistry, School of Advanced Science and Engineering, Waseda University, Tokyo 169-8555 (Japan); Research Institute for Science and Engineering, Waseda University, Tokyo 169-8555 (Japan); CREST, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Elements Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University, Katsura, Kyoto 615-8520 (Japan)

2013-12-28T23:59:59.000Z

490

Thermal Gradient Holes At Cove Fort Area - Vapor (Warpinski, Et Al., 2002)  

Open Energy Info (EERE)

2) 2) Exploration Activity Details Location Cove Fort Geothermal Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness not indicated DOE-funding Unknown Notes The project at Cove Fort/Sulphurdale in Utah, T26S R6/7W, is concerned with locating and drilling a 900-meter well to explore the western extension of the Cove Fort-Sulphurdale geothermal area. The geophysical exploration consisted of resistivity, ground magnetic, and microgravity surveys that were made to site the well in an optimum location. Drilling of the test well was completed in the fall of 2001 and results are currently being evaluated. The total depth of the well is 598 m with a non-equilibrated maximum temperature probably in the range of 157degrees C and a very complicated geologic structure.

491

The stellar accretion origin of stellar population gradients in massive galaxies at large radii  

E-Print Network [OSTI]

We investigate the evolution of stellar population gradients from $z=2$ to $z=0$ in massive galaxies at large radii ($r > 2R_{\\mathrm{eff}}$) using ten cosmological zoom simulations of halos with $6 \\times 10^{12} M_{\\odot} simulations follow metal cooling and enrichment from SNII, SNIa and AGB winds. We explore the differential impact of an empirical model for galactic winds that reproduces the mass-metallicity relation and its evolution with redshift. At larger radii the galaxies, for both models, become more dominated by stars accreted from satellite galaxies in major and minor mergers. In the wind model, fewer stars are accreted, but they are significantly more metal poor resulting in steep global metallicity ($\\langle \

Hirschmann, Michaela; Ostriker, Jeremiah P; Forbes, Duncan A; Duc, Pierre-Alain; Dav, Romeel; Oser, Ludwig; Karabal, Emin

2014-01-01T23:59:59.000Z

492

Double-hybrid density-functional theory with meta-generalized-gradient approximations  

SciTech Connect (OSTI)

We extend the previously proposed one-parameter double-hybrid density-functional theory [K. Sharkas, J. Toulouse, and A. Savin, J. Chem. Phys. 134, 064113 (2011)] to meta-generalized-gradient-approximation (meta-GGA) exchange-correlation density functionals. We construct several variants of one-parameter double-hybrid approximations using the Tao-Perdew-Staroverov-Scuseria (TPSS) meta-GGA functional and test them on test sets of atomization energies and reaction barrier heights. The most accurate variant uses the uniform coordinate scaling of the density and of the kinetic energy density in the correlation functional, and improves over both standard Kohn-Sham TPSS and second-order Mller-Plesset calculations.

Souvi, Sidi M. O., E-mail: sidi.souvi@irsn.fr; Sharkas, Kamal; Toulouse, Julien, E-mail: julien.toulouse@upmc.fr [Sorbonne Universits, UPMC Univ Paris 06, UMR 7616, Laboratoire de Chimie Thorique, F-75005 Paris (France) [Sorbonne Universits, UPMC Univ Paris 06, UMR 7616, Laboratoire de Chimie Thorique, F-75005 Paris (France); CNRS, UMR 7616, Laboratoire de Chimie Thorique, F-75005 Paris (France)

2014-02-28T23:59:59.000Z

493

Storage and Manipulation of Light Using a Raman Gradient Echo Process  

E-Print Network [OSTI]

The Gradient Echo Memory (GEM) scheme has potential to be a suitable protocol for storage and retrieval of optical quantum information. In this paper, we review the properties of the $\\Lambda$-GEM method that stores information in the ground states of three-level atomic ensembles via Raman coupling. The scheme is versatile in that it can store and re-sequence multiple pulses of light. To date, this scheme has been implemented using warm rubidium gas cells. There are different phenomena that can influence the performance of these atomic systems. We investigate the impact of atomic motion and four-wave mixing and present experiments that show how parasitic four-wave mixing can be mitigated. We also use the memory to demonstrate preservation of pulse shape and the backward retrieval of pulses.

Hosseini, M; Campbell, G T; Lam, P K; Buchler, B C

2012-01-01T23:59:59.000Z

494

Macroalgal diversity along the Baltic Sea salinity gradient challenges Remanes species-minimum concept  

Science Journals Connector (OSTI)

Remanes species-minimum concept, which states that the lowest number of taxa occurs at the horohalinicum (58psu), was tested by investigating macroalgal diversity on hard substrates along the natural salinity gradient in the Baltic Sea. Field data on species occurrence and abundance were collected by SCUBA diving along 10 transects of the Finnish, Swedish and German coasts, covering a salinity range from 3.9 to 27psu. Macroalgal species numbers declined steadily with salinity, decreasing until 7.2psu was reached, but in the horohalinicum, a marked reduction of species number and a change in diversity were indicated by the Shannon index and evenness values. The non-linear decrease in macroalgal diversity at 58psu and the lack of increase in species numbers at salinities below 5psu imply a restricted applicability of Remanes species-minimum concept to macroalgae.

Hendrik Schubert; Peter Feuerpfeil; Ronny Marquardt; Irena Telesh; Sergei Skarlato

2011-01-01T23:59:59.000Z

495

Miamisburg salt-gradient solar pond: mid-1980 status report. [For swimming pool heating  

SciTech Connect (OSTI)

The largest salt-gradient solar pond in the US was constructed by the City of Miamisburg, Ohio to provide heat for an outdoor swimming pool in the summer and an adjacent recreational building from October to December. The pond which occupies an area of 2020 m/sup 2/ was installed for $35/m/sup 2/ and is conservatively estimated to provide 1012 GJ/year (960 million Btu) at a cost of $6.80/GJ ($7.20/MBtu). During July to September 1979, 143.5 GJ (136 million Btu) of heat was utilized. Several unpredicted operational concerns have been noted related to corrosion of the metallic heat exchanger and the failure of selected seams in the plastic liner. Based upon two years of experience, suggestions are made to prevent or minimize these difficulties.

Wittenberg, L.J.; Harris, M.J.

1980-01-01T23:59:59.000Z

496

Low-Mach-number turbulence in interstellar gas revealed by radio polarization gradients  

E-Print Network [OSTI]

The interstellar medium of the Milky Way is multi-phase, magnetized and turbulent. Turbulence in the interstellar medium produces a global cascade of random gas motions, spanning scales ranging from 100 parsecs to 1000 kilometres. Fundamental parameters of interstellar turbulence such as the sonic Mach number (the speed of sound) have been difficult to determine because observations have lacked the sensitivity and resolution to directly image the small-scale structure associated with turbulent motion. Observations of linear polarization and Faraday rotation in radio emission from the Milky Way have identified unusual polarized structures that often have no counterparts in the total radiation intensity or at other wavelengths, and whose physical significance has been unclear. Here we report that the gradient of the Stokes vector (Q,U), where Q and U are parameters describing the polarization state of radiation, provides an image of magnetized turbulence in diffuse ionized gas, manifested as a complex filamenta...

Gaensler, Bryan M; Burkhart, Blakesley; Newton-McGee, Katherine J; Ekers, Ronald D; Lazarian, Alex; McClure-Griffiths, Naomi M; Robishaw, Timothy; Dickey, John M; Green, Anne J; 10.1038/nature10446

2011-01-01T23:59:59.000Z

497

Large Scale Structures a Gradient Lines: the case of the Trkal Flow  

E-Print Network [OSTI]

A specific asymptotic expansion at large Reynolds numbers (R)for the long wavelength perturbation of a non stationary anisotropic helical solution of the force less Navier-Stokes equations (Trkal solutions) is effectively constructed of the Beltrami type terms through multi scaling analysis. The asymptotic procedure is proved to be valid for one specific value of the scaling parameter,namely for the square root of the Reynolds number (R).As a result large scale structures arise as gradient lines of the energy determined by the initial conditions for two anisotropic Beltrami flows of the same helicity.The same intitial conditions determine the boundaries of the vortex-velocity tubes, containing both streamlines and vortex lines

Libin, Alexander S

2010-01-01T23:59:59.000Z

498

Large Scale Structures a Gradient Lines: the case of the Trkal Flow  

E-Print Network [OSTI]

A specific asymptotic expansion at large Reynolds numbers (R)for the long wavelength perturbation of a non stationary anisotropic helical solution of the force less Navier-Stokes equations (Trkal solutions) is effectively constructed of the Beltrami type terms through multi scaling analysis. The asymptotic procedure is proved to be valid for one specific value of the scaling parameter,namely for the square root of the Reynolds number (R).As a result large scale structures arise as gradient lines of the energy determined by the initial conditions for two anisotropic Beltrami flows of the same helicity.The same intitial conditions determine the boundaries of the vortex-velocity tubes, containing both streamlines and vortex lines

Alexander S. Libin

2010-07-13T23:59:59.000Z

499

Thermal Gradient Holes At Tungsten Mountain Area (Shevenell, Et Al., 2008)  

Open Energy Info (EERE)

Shevenell, Et Al., 2008) Shevenell, Et Al., 2008) Exploration Activity Details Location Tungsten Mountain Area Exploration Technique Thermal Gradient Holes Activity Date Usefulness useful DOE-funding Unknown Notes Collaboration with the gold mining industry has brought two new geothermal discoveries to the attention of the geothermal community. Exploration holes at Tungsten Mountain and McGuiness Hills (Figure 1) in 2004 and 2005 encountered hot water and steam at depths of meters with fluid geothermometry indicating reservoir temperatures of 170 to 200oC. More information can be obtained from the Nevada Bureau of Mines and Geology web site (www.nbmg.unr.edu/geothermal/gtmap.pdf), and from a PowerPoint presentation titled 'Geothermal Exploration Short Stories' posted on the Geothermal Resources Council web site

500

Seismic gravity-gradient noise in interferometric gravitational-wave detectors  

E-Print Network [OSTI]

When ambient seismic waves pass near an interferometric gravitational-wave detector, they induce density perturbations in the earth which produce fluctuating gravitational forces on the interferometer's test masses. These forces mimic a stochastic background of gravitational waves and thus constitute noise. We compute this noise using the theory of multimode Rayleigh and Love waves propagating in a layered medium that approximates the geological strata at the LIGO sites. We characterize the noise by a transfer function $T(f) \\equiv \\tilde x(f)/\\tilde W(f)$ from the spectrum of direction averaged ground motion $\\tilde W(f)$ to the spectrum of test mass motion $\\tilde x(f) = L\\tilde h(f)$ (where $L$ is the length of the interferometer's arms, and $\\tilde h(f)$ is the spectrum of gravitational-wave noise). This paper's primary foci are (i) a study of how $T(f)$ depends on the various seismic modes; (ii) an attempt to estimate which modes are excited at the LIGO sites at quiet and noisy times; and (iii) a corresponding estimate of the seismic gravity-gradient noise level. At quiet times the noise is below the benchmark noise level of ``advanced LIGO interferometers'' (although not by much near 10 Hz); it may significantly exceed this level at noisy times. The lower edge of our quiet-time noise is a limit beyond which there is little gain from further improvements in vibration isolation and thermal noise, unless one also reduces seismic gravity-gradient noise. Two methods of reduction are discussed: monitoring the earth's density perturbations, computing their gravitational forces, and correcting the data for those forces; and constructing narrow moats around the interferometers' test masses to shield out the fundamental-mode Rayleigh waves, which we suspect dominate at quiet times.

Scott A. Hughes; Kip S. Thorne

1998-06-03T23:59:59.000Z